Progranulin, a Major Secreted Protein of Mouse Adipose-Derived Stem Cells, Inhibits Light-Induced Retinal Degeneration

PubMed Central

Tsuruma, Kazuhiro; Yamauchi, Mika; Sugitani, Sou; Otsuka, Tomohiro; Ohno, Yuta; Nagahara, Yuki; Ikegame, Yuka; Shimazawa, Masamitsu; Yoshimura, Shinichi; Iwama, Toru

2014-01-01

Adipose tissue stromal vascular fraction contains mesenchymal stem cells, which show protective effects when administered to damaged tissues, mainly through secreted trophic factors. We examined the protective effects of adipose-derived stem cells (ASCs) and ASC-conditioned medium (ASC-CM) against retinal damage and identified the neuroprotective factors in ASC-CM. ASCs and mature adipocytes were isolated from mouse subcutaneous tissue. ASCs were injected intravitreally in a mouse model of light-induced retinal damage, and ASC injection recovered retinal function as measured by electroretinogram and inhibited outer nuclear layer, thinning, without engraftment of ASCs. ASC-CM and mature adipocyte-conditioned medium were collected after 72 hours of culture. In vitro, H2O2- and light-induced cell death was reduced in a photoreceptor cell line with ASC-CM but not with mature adipocyte-conditioned medium. In vivo, light-induced photoreceptor damage was evaluated by measurement of outer nuclear layer thickness at 5 days after light exposure and by electroretinogram recording. ASC-CM significantly inhibited photoreceptor degeneration and retinal dysfunction after light exposure. Progranulin was identified as a major secreted protein of ASCs that showed protective effects against retinal damage in vitro and in vivo. Furthermore, progranulin phosphorylated extracellular signal-regulated kinase, cAMP response element binding protein, and hepatocyte growth factor receptor, and protein kinase C signaling pathways were involved in the protective effects of progranulin. These findings suggest that ASC-CM and progranulin have neuroprotective effects in the light-induced retinal-damage model. Progranulin may be a potential target for the treatment of the degenerative diseases of the retina. PMID:24233842

Progranulin, a major secreted protein of mouse adipose-derived stem cells, inhibits light-induced retinal degeneration.

PubMed

Tsuruma, Kazuhiro; Yamauchi, Mika; Sugitani, Sou; Otsuka, Tomohiro; Ohno, Yuta; Nagahara, Yuki; Ikegame, Yuka; Shimazawa, Masamitsu; Yoshimura, Shinichi; Iwama, Toru; Hara, Hideaki

2014-01-01

Adipose tissue stromal vascular fraction contains mesenchymal stem cells, which show protective effects when administered to damaged tissues, mainly through secreted trophic factors. We examined the protective effects of adipose-derived stem cells (ASCs) and ASC-conditioned medium (ASC-CM) against retinal damage and identified the neuroprotective factors in ASC-CM. ASCs and mature adipocytes were isolated from mouse subcutaneous tissue. ASCs were injected intravitreally in a mouse model of light-induced retinal damage, and ASC injection recovered retinal function as measured by electroretinogram and inhibited outer nuclear layer, thinning, without engraftment of ASCs. ASC-CM and mature adipocyte-conditioned medium were collected after 72 hours of culture. In vitro, H2O2- and light-induced cell death was reduced in a photoreceptor cell line with ASC-CM but not with mature adipocyte-conditioned medium. In vivo, light-induced photoreceptor damage was evaluated by measurement of outer nuclear layer thickness at 5 days after light exposure and by electroretinogram recording. ASC-CM significantly inhibited photoreceptor degeneration and retinal dysfunction after light exposure. Progranulin was identified as a major secreted protein of ASCs that showed protective effects against retinal damage in vitro and in vivo. Furthermore, progranulin phosphorylated extracellular signal-regulated kinase, cAMP response element binding protein, and hepatocyte growth factor receptor, and protein kinase C signaling pathways were involved in the protective effects of progranulin. These findings suggest that ASC-CM and progranulin have neuroprotective effects in the light-induced retinal-damage model. Progranulin may be a potential target for the treatment of the degenerative diseases of the retina.

An ex vivo gene therapy approach in X-linked retinoschisis.

PubMed

Bashar, Abu E; Metcalfe, Andrew L; Viringipurampeer, Ishaq A; Yanai, Anat; Gregory-Evans, Cheryl Y; Gregory-Evans, Kevin

2016-01-01

X-linked retinoschisis (XLRS) is juvenile-onset macular degeneration caused by haploinsufficiency of the extracellular cell adhesion protein retinoschisin (RS1). RS1 mutations can lead to either a non-functional protein or the absence of protein secretion, and it has been established that extracellular deficiency of RS1 is the underlying cause of the phenotype. Therefore, we hypothesized that an ex vivo gene therapy strategy could be used to deliver sufficient extracellular RS1 to reverse the phenotype seen in XLRS. Here, we used adipose-derived, syngeneic mesenchymal stem cells (MSCs) that were genetically modified to secrete human RS1 and then delivered these cells by intravitreal injection to the retina of the Rs1h knockout mouse model of XLRS. MSCs were electroporated with two transgene expression systems (cytomegalovirus (CMV)-controlled constitutive and doxycycline-induced Tet-On controlled inducible), both driving expression of human RS1 cDNA. The stably transfected cells, using either constitutive mesenchymal stem cell (MSC) or inducible MSC cassettes, were assayed for their RS1 secretion profile. For single injection studies, 100,000 genetically modified MSCs were injected into the vitreous cavity of the Rs1h knockout mouse eye at P21, and data were recorded at 2, 4, and 8 weeks post-injection. The control groups received either unmodified MSCs or vehicle injection. For the multiple injection studies, the mice received intravitreal MSC injections at P21, P60, and P90 with data collection at P120. For the single- and multiple-injection studies, the outcomes were measured with electroretinography, optokinetic tracking responses (OKT), histology, and immunohistochemistry. Two lines of genetically modified MSCs were established and found to secrete RS1 at a rate of 8 ng/million cells/day. Following intravitreal injection, RS1-expressing MSCs were found mainly in the inner retinal layers. Two weeks after a single injection of MSCs, the area of the schisis cavities was reduced by 65% with constitutive MSCs and by 83% with inducible MSCs, demonstrating improved inner nuclear layer architecture. This benefit was maintained up to 8 weeks post-injection and corresponded to a significant improvement in the electroretinogram (ERG) b-/a-wave ratio at 8 weeks (2.6 inducible MSCs; 1.4 untreated eyes, p<0.05). At 4 months after multiple injections, the schisis cavity areas were reduced by 78% for inducible MSCs and constitutive MSCs, more photoreceptor nuclei were present (700/µm constitutive MSC; 750/µm inducible MSC; 383/µm untreated), and the ERG b-wave was significantly improved (threefold higher with constitutive MSCs and twofold higher with inducible MSCs) compared to the untreated control group. These results establish that extracellular delivery of RS1 rescues the structural and functional deficits in the Rs1h knockout mouse model and that this ex vivo gene therapy approach can inhibit progression of disease. This proof-of-principle work suggests that other inherited retinal degenerations caused by a deficiency of extracellular matrix proteins could be targeted by this strategy.

microRNA-21a-5p/PDCD4 axis regulates mesenchymal stem cell-induced neuroprotection in acute glaucoma.

PubMed

Su, Wenru; Li, Zuohong; Jia, Y; Zhu, Yingting; Cai, Wenjia; Wan, Peixing; Zhang, Yingying; Zheng, Song Guo; Zhuo, Yehong

2017-08-01

Mesenchymal stem cells (MSCs) have been demonstrated to have promising therapeutic benefits for a variety of neurological diseases; however, the underlying mechanisms are poorly understood. Here, we showed that intravitreal infusion of MSCs promoted retinal ganglion cell (RGC) survival in a mouse model of acute glaucoma, with significant inhibition of microglial activation, production of TNF-α, IL-1β, and reactive oxygen species, as well as caspase-8 and caspase-3 activation. In vitro, MSCs inhibited both caspase-8-mediated RGC apoptosis and microglial activation, partly via the action of stanniocalcin 1 (STC1). Furthermore, we found that microRNA-21a-5p (miR-21) and its target, PDCD4, were essential for STC1 production and the neuroprotective property of MSCs in vitro and in vivo. Importantly, miR-21 overexpression or PDCD4 knockdown augmented MSC-mediated neuroprotective effects on acute glaucoma. These data highlight a previously unrecognized neuroprotective mechanism by which the miR-21/PDCD4 axis induces MSCs to secrete STC1 and other factors that exert neuroprotective effects. Therefore, modulating the miR-21/PDCD4 axis might be a promising strategy for clinical treatment of acute glaucoma and other neurological diseases. © The Author (2017). Published by Oxford University Press on behalf of Journal of Molecular Cell Biology, IBCB, SIBS, CAS. All rights reserved.

A Novel Method Combining Vitreous Aspiration and Intravitreal AAV2/8 Injection Results in Retina-Wide Transduction in Adult Mice.

PubMed

Da Costa, Romain; Röger, Carsten; Segelken, Jasmin; Barben, Maya; Grimm, Christian; Neidhardt, John

2016-10-01

Gene therapies to treat eye disorders have been extensively studied in the past 20 years. Frequently, adeno-associated viruses were applied to the subretinal or intravitreal space of the eye to transduce retinal cells with nucleotide sequences of therapeutic potential. In this study we describe a novel intravitreal injection procedure that leads to a reproducible adeno-associated virus (AAV)2/8-mediated transduction of more than 70% of the retina. Prior to a single intravitreal injection of a enhanced green fluorescent protien (GFP)-expressing viral suspension, we performed an aspiration of vitreous tissue from wild-type C57Bl/6J mice. One and one-half microliters of AAV2/8 suspension was injected. Funduscopy, optical coherence tomography (OCT), laser scanning microscopy of retinal flat mounts, cryosections of eye cups, and ERG recordings verified the efficacy and safety of the method. The combination of vitreous aspiration and intravitreal injection resulted in an almost complete transduction of the retina in approximately 60% of the eyes and showed transduced cells in all retinal layers. Photoreceptors and RPE cells were predominantly transduced. Eyes presented with well-preserved retinal morphology. Electroretinographic recordings suggested that the new combination of techniques did not cause significant alterations of the retinal physiology. We show a novel application technique of AAV2/8 to the vitreous of mice that leads to widespread transduction of the retina. The results of this study have implications for virus-based gene therapies and basic science; for example, they might provide an approach to apply gene replacement strategies or clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 in vivo. It may further help to develop similar techniques for larger animal models or humans.

Determination of a No-Observable Effect Level for Endotoxin Following a Single Intravitreal Administration to Dutch Belted Rabbits.

PubMed

Bantseev, Vladimir; Miller, Paul E; Bentley, Ellison; Schuetz, Chris; Streit, Tim M; Christian, Brian J; Farman, Cindy; Booler, Helen; Thackaberry, Evan A

2017-03-01

The purpose of this study was to characterize the inflammatory response and determine a no-observable effect level (NOEL) in rabbit eyes after endotoxin intravitreal (ITV) injection. Fifty-three naïve male Dutch Belted rabbits were treated with a single 50-μL ITV injection ranging from 0.01 to 0.75 endotoxin units/eye (EU/eye) and monitored for up to 42 days post treatment. Ophthalmic examination included slit-lamp biomicroscopy and indirect ophthalmoscopy. Laser flare photometry was performed in a subset of animals. On days 2, 8, 16, and 43, a subset of animals was necropsied and eyes processed for histopathological evaluation. Intravitreal injection of endotoxin at ≥0.05 EU/eye resulted in a dose-related anterior segment inflammation response. No aqueous flare or cell response was noted in the 0.01 EU/eye dose group. A more delayed posterior segment response characterized by vitreal cell response was observed beginning on day 5, peaking on day 9, and decreasing starting on day 16 that persisted at trace to a level of 1+ on day 43. Microscopy findings of infiltrates of minimal mixed inflammatory cells in the vitreous and subconjunctiva and proteinaceous fluid in the anterior chamber and/or vitreous were observed in eyes given ≥0.1 EU/eye. We defined the NOEL for ITV endotoxin to be 0.01 EU/eye, suggesting that the vitreal cavity is more sensitive to the effects of endotoxin than the anterior segment and aqueous chamber. These data highlight the importance of assessing endotoxin level in intravitreal formulations, as levels as low as 0.05 EU/eye may confound the safety evaluations of intravitreal therapeutics in rabbits.

Vitreous web after pars plana vitrectomy and bevacizumab with fluid-air exchange.

PubMed

Chiang, Allen; Reddy, Shantan; Tsui, Irena; Hubschman, Jean-Pierre

2011-01-01

Intravitreal bevacizumab may result in intraocular inflammation of infectious and non-infectious etiology. Appropriate recognition of a sterile process can circumvent unnecessary treatment for endophthalmitis. Observational case report. A marked web-like inflammatory response within the vitreous following intraoperative intravitreal bevacizumab is described in a patient with pre-proliferative diabetic retinopathy, macular edema, and epiretinal membrane who underwent pars plana vitrectomy, membrane peel, endolaser, and fluid-air exchange. Wide-field fundus photography captured the full extent of this reaction. On post-operative day one, the patient presented with vitreous opacities in the form of a web of multiple white strands inferior to an air bubble, with minimal anterior or vitreous cell. At one week, the inflammatory reaction had completely resolved. Existing reports of intraocular inflammation following intravitreal bevacizumab range from uveitis to infectious endophthalmitis. With wide-field fundus imaging, we report an acute, marked web-like inflammatory response following intraoperative intravitreal bevacizumab that resolved spontaneously.

Single-Cell Resolution Imaging of Retinal Ganglion Cell Apoptosis In Vivo Using a Cell-Penetrating Caspase-Activatable Peptide Probe

PubMed Central

Qiu, Xudong; Johnson, James R.; Wilson, Bradley S.; Gammon, Seth T.; Piwnica-Worms, David; Barnett, Edward M.

2014-01-01

Peptide probes for imaging retinal ganglion cell (RGC) apoptosis consist of a cell-penetrating peptide targeting moiety and a fluorophore-quencher pair flanking an effector caspase consensus sequence. Using ex vivo fluorescence imaging, we previously validated the capacity of these probes to identify apoptotic RGCs in cell culture and in an in vivo rat model of N-methyl- D-aspartate (NMDA)-induced neurotoxicity. Herein, using TcapQ488, a new probe designed and synthesized for compatibility with clinically-relevant imaging instruments, and real time imaging of a live rat RGC degeneration model, we fully characterized time- and dose-dependent probe activation, signal-to-noise ratios, and probe safety profiles in vivo. Adult rats received intravitreal injections of four NMDA concentrations followed by varying TcapQ488 doses. Fluorescence fundus imaging was performed sequentially in vivo using a confocal scanning laser ophthalmoscope and individual RGCs displaying activated probe were counted and analyzed. Rats also underwent electroretinography following intravitreal injection of probe. In vivo fluorescence fundus imaging revealed distinct single-cell probe activation as an indicator of RGC apoptosis induced by intravitreal NMDA injection that corresponded to the identical cells observed in retinal flat mounts of the same eye. Peak activation of probe in vivo was detected 12 hours post probe injection. Detectable fluorescent RGCs increased with increasing NMDA concentration; sensitivity of detection generally increased with increasing TcapQ488 dose until saturating at 0.387 nmol. Electroretinography following intravitreal injections of TcapQ488 showed no significant difference compared with control injections. We optimized the signal-to-noise ratio of a caspase-activatable cell penetrating peptide probe for quantitative non-invasive detection of RGC apoptosis in vivo. Full characterization of probe performance in this setting creates an important in vivo imaging standard for functional evaluation of future probe analogues and provides a basis for extending this strategy into glaucoma-specific animal models. PMID:24586415

Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes in the Treatment of Eye Diseases.

PubMed

Harrell, C Randall; Simovic Markovic, Bojana; Fellabaum, Crissy; Arsenijevic, Aleksandar; Djonov, Valentin; Arsenijevic, Nebojsa; Volarevic, Vladislav

2018-05-18

Mesenchymal stem cells (MSCs) were, due to their immunomodulatory and pro-angiogenic characteristics, extensively explored as new therapeutic agents in cell-based therapy of uveitis, glaucoma, retinal and ocular surface diseases.Since it was recently revealed that exosomes play an important role in biological functions of MSCs, herewith we summarized current knowledge about the morphology, structure, phenotype and functional characteristics of MSC-derived exosomes emphasizing their therapeutic potential in the treatment of eye diseases.MSC-derived exosomes were as efficient as transplanted MSCs in limiting the extent of eye injury and inflammation. Immediately after intravitreal injection, MSC-derived exosomes, due to nano-dimension, diffused rapidly throughout the retina and significantly attenuated retinal damage and inflammation. MSC-derived exosomes successfully delivered trophic and immunomodulatory factors to the inner retina and efficiently promoted survival and neuritogenesis of injured retinal ganglion cells. MSC-derived exosomes efficiently suppressed migration of inflammatory cells, attenuated detrimental Th1 and Th17 cell-driven immune response and ameliorated experimental autoimmune uveitis. MSC-derived exosomes were able to fuse with the lysosomes within corneal cells, enabling delivering of MSC-derived active β-glucuronidase and consequent catabolism of accumulated glycosaminoglycans, indicating their therapeutic potential in the treatment of Mucopolysaccharidosis VII (Sly Syndrome). Importantly, beneficent effects were noticed only in animals that received MSC-derived exosomes and were not seen after therapy with fibroblasts-derived exosomes confirming specific therapeutic potential of MSCs and their products in the treatment of eye diseases.In conclusion, MSC-derived exosomes represent potentially new therapeutic agents in the therapy of degenerative and inflammatory ocular diseases.

Effects of radiotherapy on uveal melanomas and adjacent tissues

PubMed Central

Groenewald, C; Konstantinidis, L; Damato, B

2013-01-01

Most uveal melanomas are treated with radiotherapy. An adequate understanding of the effects of radiation on the tumour and the healthy ocular tissues is necessary. Ionizing radiation damages cell membranes, organelles, and DNA. Irradiated cells are lysed or undergo apoptosis, necrosis, and senescence. These effects occur in tumour cells and vascular endothelial cells, resulting in tumour shrinkage, ischaemia, infarction, exudation, and fibrosis, which can cause exudative maculopathy, serous retinal detachment, rubeosis, and neovascular glaucoma (ie, ‘toxic tumour syndrome'). Such abnormalities must be distinguished from collateral damage to healthy ocular tissues that receive high doses of radiation, and these include radiation-induced retinopathy, optic neuropathy, choroidopathy, cataract, and scleral necrosis. Radiation retinopathy can be treated effectively with photodynamic therapy, anti-angiogenic agents, and intravitreal steroid injections. In some patients, optic neuropathy may improve with intravitreal steroids or anti-angiogenic agents. Neovascular glaucoma resolves with intra-cameral bevacizumab. Exudative retinal detachment can regress with intra-vitreal steroid injections. Cataract is treated in the usual manner. Scleral necrosis, if severe, may require grafting, possibly using a lamellar flap from the same eye. Depending on the bulk of the residual toxic tumour, treatment can consist of intra-vitreal steroids and/or anti-angiogenic agents, transpupillary thermotherapy or photodynamic therapy to the tumour, or surgical removal of the tumour by endo- or exo-resection. Measures aimed at preventing collateral damage include eccentric placement of ruthenium plaques or iodine seeds and delivery of a notched proton beam. The decision to treat a uveal melanoma with radiotherapy requires the ability to manage iatrogenic side effects and complications. PMID:23196647

Delayed Administration of Bone Marrow Mesenchymal Stem Cell Conditioned Medium Significantly Improves Outcome After Retinal Ischemia in Rats

PubMed Central

Dreixler, John C.; Poston, Jacqueline N.; Balyasnikova, Irina; Shaikh, Afzhal R.; Tupper, Kelsey Y.; Conway, Sineadh; Boddapati, Venkat; Marcet, Marcus M.; Lesniak, Maciej S.; Roth, Steven

2014-01-01

Purpose. Delayed treatment after ischemia is often unsatisfactory. We hypothesized that injection of bone marrow stem cell (BMSC) conditioned medium after ischemia could rescue ischemic retina, and in this study we characterized the functional and histological outcomes and mechanisms of this neuroprotection. Methods. Retinal ischemia was produced in adult Wistar rats by increasing intraocular pressure for 55 minutes. Conditioned medium (CM) from rat BMSCs or unconditioned medium (uCM) was injected into the vitreous 24 hours after the end of ischemia. Recovery was assessed 7 days after ischemia using electroretinography, at which time we euthanized the animals and then prepared 4-μm-thick paraffin-embedded retinal sections. TUNEL and Western blot were used to identify apoptotic cells and apoptosis-related gene expression 24 hours after injections; that is, 48 hours after ischemia. Protein content in CM versus uCM was studied using tandem mass spectrometry, and bioinformatics methods were used to model protein interactions. Results. Intravitreal injection of CM 24 hours after ischemia significantly improved retinal function and attenuated cell loss in the retinal ganglion cell layer. CM attenuated postischemic apoptosis and apoptosis-related gene expression. By spectral counting, 19 proteins that met stringent identification criteria were increased in the CM compared to uCM; the majority were extracellular matrix proteins that mapped into an interactional network together with other proteins involved in cell growth and adhesion. Conclusions. By restoring retinal function, attenuating apoptosis, and preventing retinal cell loss after ischemia, CM is a robust means of delayed postischemic intervention. We identified some potential candidate proteins for this effect. PMID:24699381

EFFECT OF INTRAVITREAL RANIBIZUMAB ON GANGLION CELL COMPLEX AND PERIPAPILLARY RETINAL NERVE FIBER LAYER IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY.

PubMed

Zucchiatti, Ilaria; Cicinelli, Maria V; Parodi, Maurizio Battaglia; Pierro, Luisa; Gagliardi, Marco; Accardo, Agostino; Bandello, Francesco

2017-07-01

To analyze the changes in ganglion cell complex and peripapillary retinal nerve fiber layer thickness, in central macular thickness and choroidal thickness on spectral domain optical coherence tomography in patients with neovascular age-related macular degeneration treated with intravitreal ranibizumab injections. All consecutive patients with untreated neovascular age-related macular degeneration received loading phase of three monthly intravitreal ranibizumab, followed by retreatments on a pro re nata protocol for 12 months. changes in ganglion cell complex and retinal nerve fiber layer at the end of follow-up. Secondary outcome: changes in best-corrected visual acuity, central macular thickness, and choroidal thickness at the end of follow-up. Choroidal thickness was measured at 500 μm, 1000 μm, and 1,500 μm intervals nasally, temporally, superiorly, and inferiorly to the fovea, respectively, on horizontal and vertical line scans centered on the fovea. Twenty-four eyes were included. Ganglion cell complex and peripapillary retinal nerve fiber layer thickness did not show statistically significant changes through 12 months (55.6 ± 18.5 and 81.9 ± 9.9 μm at baseline, 52.7 ± 19.3 and 84.6 ± 15.5 μm at month 12, P > 0.05). Central macular thickness showed progressive decrease from baseline to month 12, with maximum reduction at month 3 (P < 0.001). Statistically significant reduction in choroidal thickness was registered in the nasal 500, 1000, and 1,500 μm from the fovea, corresponding to the papillomacular region (from 169.6 ± 45.3 to 153.9 ± 46.9, P < 0.001). Intravitreal ranibizumab injections did not affect retinal nerve fiber layer and ganglion cell complex thickness in 1-year follow-up. Choroidal thickness in papillomacular area and central macular thickness was significantly reduced at the end of treatment. Further studies, with larger sample, longer follow-up, and greater number of injections, are warranted.

Transfection with CXCR4 potentiates homing of mesenchymal stem cells in vitro and therapy of diabetic retinopathy in vivo.

PubMed

Wang, Jian; Zhang, Wei; He, Guang-Hui; Wu, Bin; Chen, Song

2018-01-01

To investigate the effect of the overexpression of C-X-C chemokine receptor type 4 (CXCR4) on homing of mesenchymal stem cells (MSCs) in vitro and therapeutic effects of diabetic retinopathy (DR) in vivo . MSCs were infected by lentivirus constructed with CXCR4. The expression of CXCR4 was examined by immunofluorescence, Western blot, and quantitative polymerase chain reaction. CXCR4-overexpressing MSCs were cultured in vitro to evaluate their chemotaxis, migration, and apoptotic activities. CXCR4-overexpressing MSCs were intravitreally injected to observe and compare their effects in a mouse model of DR. The histological structure of DR in rats was inspected by hematoxylin and eosin staining. The expression of rhodopsin, neuron-specific enolase (NSE), and inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α was examined by Western blot and immunohistochemical analyses. The transduction of MSCs by lentivirus was effective, and the transduced MSCs had high expression levels of CXCR4 gene and protein. Improved migration activities were observed in CXCR4-overexpressing MSCs. Further, reduced retinal damage, upregulation of rhodopsin and NSE protein, and downregulation of inflammatory cytokines IL-6 and TNF-α were observed in CXCR4-overexpressing MSCs in vivo . The homing of MSCs can be enhanced by upregulating CXCR4 levels, possibly improving histological structures of DR. CXCR4-overexpressing MSCs can be a novel strategy for treating DR.

Retinal and optic nerve atrophy induced by intravitreous vincristine in the primate.

PubMed Central

Green, W R

1975-01-01

Vincristine is known to be toxic to neural tissue, where it is thought to react with microtubules and impair axonal transport. Intravitreous vincristing-induced changes of the retina have been reported to be reversible after 10 micrograms. In the present study, the effects of 0.01 to 100 micrograms of intravitreous vincristine in monkeys were studied ophthalmoscopically and by light microscopy and electron microscopy. Retinal degeneration and optic atrophy were evident ophthalmoscopically in two to three weeks. Morphological changes included swelling of retinal neurons, loss of organelles and microtubules and accumulation of fibrillar-granular material. Progression of effects, with plasma membrane rupture and cell death, was observed with all doses of 0.1 micrograms and higher. The retina and optic nerve of monkeys appear to be more sensitive to intravitreous vincristine than are the same structures in certain lower animals. Images FIGURE 10 FIGURE 18 FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 11 FIGURE 12 FIGURE 13 FIGURE 14 FIGURE 15 FIGURE 16 FIGURE 17 FIGURE 19 FIGURE 20 PMID:813350

NGF/anti-VEGF combined exposure protects RCS retinal cells and photoreceptors that underwent a local worsening of inflammation.

PubMed

Rocco, Maria Luisa; Balzamino, Bijorn Omar; Esposito, Graziana; Petrella, Carla; Aloe, Luigi; Micera, Alessandra

2017-03-01

Our previous study highlighted the potential nerve growth factor (NGF) effect on damaged photoreceptors from a rat model of spontaneous Retinitis Pigmentosa (RP). Herein, we tested the combined NGF/anti-vascular endothelial growth factor (αVEGF) effect on cultured retinal cells isolated from Royal College of Surgeons (RCS) rats receiving an intravitreal VEGF injection (iv-VEGF) to exacerbate retinal inflammation/neovascularization. RCS (n = 75) rats were equally grouped as untreated (n = 25), iv-saline (single saline intravitreal injection; n = 25) and iv-VEGF (single VEGF intravitreal injection; n = 25). Morphological and biochemical analysis or in vitro stimulations with the biomolecular investigation were carried out on explanted retinas. Isolated retinal cells were treated with NGF and αVEGF, either alone or in combination, for 6 days and cells were harvested for morphological and biomolecular analyses. Infiltrating inflammatory cells were detected in iv-VEGF exposed RCS retinas, indicative of exacerbated inflammation and neovascularization. In cell cultures, NGF/αVEGF significantly increased retinal cell survival as well as rhodopsin expression and neurite outgrowth in photoreceptors. Particularly, NGF/αVEGF upregulated Bcl-2 mRNA, downregulated Bax mRNA, upregulated trkA NGFR mRNA and finally upregulated both NGF mRNA and protein. These data confirm and extend our previous findings on NGF-photoreceptor crosstalk, highlighting that the NGF/αVEGF combination might be an interesting approach for improving neuroprotection of RCS retinal cells and likewise photoreceptors in the presence of neovascularization. Further studies are required to translate this in vitro approach into clinical practice.

Acute sterile endophthalmitis following intravitreal bevacizumab: case series

PubMed Central

Orozco-Hernández, Axel; Ortega-Larrocea, Ximena; Sánchez-Bermúdez, Gustavo; García-Aguirre, Gerardo; Cantón, Virgilio Morales; Velez-Montoya, Raul

2014-01-01

Background Since the ophthalmological community adopted the use of intravitreal bevacizumab as an accepted off-label treatment for neovascular diseases, the amount of knowledge regarding its effects and properties has been increasing continually. In the last few years, there have been an increasing number of reports about sterile intraocular inflammation and intraocular pressure elevations after intravitreal bevacizumab. In the following case series, we describe the clinical presentation and outcomes of ten consecutive cases of patients developing mild-to-severe sterile intraocular inflammation after intravitreal bevacizumab and their management. Methods This report presents a retrospective case series. We reviewed the medical records of ten consecutive patients from a group of 46, in whom repackaged bevacizumab in individual aliquots from two vials from the same batch were used. All surgical procedures were performed using standard sterile techniques in the operating room. At each follow-up visit, patients underwent a complete ophthalmological examination including visual acuity assessment, intraocular pressure, biomicroscopy, and posterior fundus examination. Results Ten patients presented sterile endophthalmitis with an onset time of 3.5±1.95 days. The clinical characteristics were mild pain, slight visual loss, conjunctival hyperemia, and various degrees of intraocular inflammation with microhypopyon. All cultures were negative. All patients were managed with topical steroids and antibiotics, except two, in whom, due to severe vitreous cells, intravitreal antibiotics were used. Three patients showed a transient elevation of intraocular pressure. Only 50% of the patients regained a visual acuity equal or better to the baseline visual acuity on file. Conclusion The increasing number of intravitreal injections of bevacizumab applied every day, due to its widespread acceptance, might be one reason why the number of cases of sterile endophthalmitis is rising. Fast recognition and accurate differential diagnosis is important to avoid unnecessary treatments and long-term complications. The low incidence of this event should not preclude the use of intravitreal injections in eyes that could benefit greatly from this therapy. PMID:25228797

Characterization of uveitis induced by use of a single intravitreal injection of bacterial lipopolysaccharide in cats.

PubMed

Del Sole, María J; Sande, Pablo H; Felipe, Antonio E; Fernandez, Diego C; Keller Sarmiento, María I; Aba, Marcelo A; Rosenstein, Ruth E

2008-11-01

To investigate the use of a single intravitreal injection of bacterial lipopolysaccharide (LPS) to experimentally induce uveitis in cats. 7 young male European shorthair cats that were considered physically and ophthalmologically healthy. In each cat, LPS was injected intravitreally into 1 eye; the contralateral eye was injected with the preparation vehicle. During a period of 45 days, both eyes were evaluated by means of clinical evaluation; assessment of the integrity of the blood-aqueous humor barrier (determined via measurement of protein concentration and cell content in samples of aqueous humor); functional analysis (via electroretinography); and following euthanasia, histologic examination of the retinas. In LPS-treated eyes, several clinical signs were observed until day 45 after injection. Compared with vehicle-treated eyes, intraocular pressure was significantly lower and protein concentration and the number of infiltrating cells were significantly higher in LPS-treated eyes. Mean amplitudes of scotopic electroretinographic a- and b-waves were significantly reduced in eyes injected with LPS, compared with findings in eyes injected with vehicle. At 45 days after injection, LPS-induced alterations in photoreceptors and the middle portion of the retina were detected histologically. Results indicated that a single intravitreal injection of LPS in eyes of cats induced clinical, biochemical, functional, and histologic changes that were consistent with the main features of naturally occurring uveitis. This technique may be a useful tool in the investigation of new treatment strategies for uveitis in cats.

Dendrimer-based targeted intravitreal therapy for sustained attenuation of neuroinflammation in retinal degeneration.

PubMed

Iezzi, Raymond; Guru, Bharath R; Glybina, Inna V; Mishra, Manoj K; Kennedy, Alexander; Kannan, Rangaramanujam M

2012-01-01

Retinal neuroinflammation, mediated by activated microglia, plays a key role in the pathogenesis of photoreceptor and retinal pigment epithelial cell loss in age-related macular degeneration and retinitis pigmentosa. Targeted drug therapy for attenuation of neuroinflammation in the retina was explored using hydroxyl-terminated polyamidoamine (PAMAM) dendrimer-drug conjugate nanodevices. We show that, upon intravitreal administration, PAMAM dendrimers selectively localize within activated outer retinal microglia in two rat models of retinal degeneration, but not in the retina of healthy controls. This pathology-dependent biodistribution was exploited for drug delivery, by covalently conjugating fluocinolone acetonide to the dendrimer. The conjugate released the drug in a sustained manner over 90 days. In vivo efficacy was assessed using the Royal College of Surgeons (RCS) rat retinal degeneration model over a four-week period when peak retinal degeneration occurs. One intravitreal injection of 1 μg of FA conjugated to 7 μg of the dendrimer was able to arrest retinal degeneration, preserve photoreceptor outer nuclear cell counts, and attenuate activated microglia, for an entire month. These studies suggest that PAMAM dendrimers (with no targeting ligands) have an intrinsic ability to selectively localize in activated microglia, and can deliver drugs inside these cells for a sustained period for the treatment of retinal neuroinflammation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Intravitreal silicon-based quantum dots as neuroprotective factors in a model of retinal photoreceptor degeneration.

PubMed

Olson, Jeffrey L; Velez-Montoya, Raul; Mandava, Naresh; Stoldt, Conrad R

2012-08-17

To study the intravitreal application of silicon quantum dots (QDs) and their capabilities to deliver electrical stimulation to the retinal cells and to assess the potential effect on retinal electrophysiology and anatomy. A Royal College of Surgeon rat model of retinal degeneration was used in this study. A total of 32 eyes were used, divided in four groups of 8 eyes each; the first group received the silicon-based QD, the second group received an inactive gold-based QD, the third group received a sham injection, and the fourth group was used as a control. An electroretinogram (ERG) was done at baseline and thereafter every week for 9 weeks. At the end of the follow-up, eyes were collected for further pathologic analysis and nuclei cell counts. Eyes within the silicon-based QD group showed a definite but transient increase in the waves of the ERG, especially in the rod response compared with the sham and control groups (P < 0.05). The pathologic examination demonstrated a higher nuclei count in the QD group, consistent with a higher cell survival rate than that in the sham and control groups in which cells degenerated as expected. Intravitreal injection of silicon-based QD seems to be safe and well tolerated, with no evident toxic reaction and demonstrates a beneficial effect by prolonging cell survival rate and improving ERG patterns in a well-established model of retinal degeneration. (ClinicalTrials.gov numbers NCT00407602, NCT01490827.).

Evaluation of polyesteramide (PEA) and polyester (PLGA) microspheres as intravitreal drug delivery systems in albino rats.

PubMed

Peters, Tobias; Kim, Seong-Woo; Castro, Vinicius; Stingl, Krunoslav; Strasser, Torsten; Bolz, Sylvia; Schraermeyer, Ulrich; Mihov, George; Zong, MengMeng; Andres-Guerrero, Vanessa; Herrero Vanrell, Rocio; Dias, Aylvin A; Cameron, Neil R; Zrenner, Eberhart

2017-04-01

To study the suitability of injectable microspheres based on poly(ester amide) (PEA) or poly lactic-co-glycolic acid (PLGA) as potential vehicles for intravitreal drug delivery in rat eyes. Dexamethasone-loaded PEA microspheres (PEA + DEX) were also evaluated. Forty male Sprague Dawley rats were divided into four groups that received different intravitreally injected microspheres: PEA group (n = 12); PLGA group (n = 12); PEA + DEX group (n = 8); and control group (no injection, n = 8). Electroretinography (ERG), fundus autofluorescence (FAF), and spectral domain optical coherence tomography (sdOCT) were performed at baseline, weeks 1 and 2, and months 1, 2, and 3 after intravitreal injection. Eyes were histologically examined using light microscopy and transmission electron microscopy at the end of the in vivo study. There were no statistically significant changes in ERG among the groups. Abnormal FAF pattern and abnormal deposits in OCT were observed after injection but almost completely disappeared between week 2 and month 3 in all injected groups. GFAP staining showed that Müller glia cell activation was most pronounced in PLGA-injected eyes. Increased cell death was not observed by TUNEL staining at month 1. In electron microscopy at month 3, the remnants of microparticles were found in the retinal cells of all injected groups, and loss of plasma membrane was seen in the PLGA group. Although morphological changes such as mild glial activation and material remnants were observed histologically 1 month and 3 months after injection in all injected groups, minor cell damage was noted only in the PLGA group at 3 months after injection. No evidence of functional abnormality relative to untreated eyes could be detected by ERG 3 months after injection in all groups. Changes observed in in vivo imaging such as OCT and FAF disappeared after 3 months in almost all cases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Glaucoma: Biological Trabecular and Neuroretinal Pathology with Perspectives of Therapy Innovation and Preventive Diagnosis

PubMed Central

Nuzzi, Raffaele; Tridico, Federico

2017-01-01

Glaucoma is a common degenerative disease affecting retinal ganglion cells (RGC) and optic nerve axons, with progressive and chronic course. It is one of the most important reasons of social blindness in industrialized countries. Glaucoma can lead to the development of irreversible visual field loss, if not treated. Diagnosis may be difficult due to lack of symptoms in early stages of disease. In many cases, when patients arrive at clinical evaluation, a severe neuronal damage may have already occurred. In recent years, newer perspective in glaucoma treatment have emerged. The current research is focusing on finding newer drugs and associations or better delivery systems in order to improve the pharmacological treatment and patient compliance. Moreover, the application of various stem cell types with restorative and neuroprotective intent may be found appealing (intravitreal autologous cellular therapy). Advances are made also in terms of parasurgical treatment, characterized by various laser types and techniques. Moreover, recent research has led to the development of central and peripheral retinal rehabilitation (featuring residing cells reactivation and replacement of defective elements), as well as innovations in diagnosis through more specific and refined methods and inexpensive tests. PMID:28928631

Safety and efficacy of intravitreal injection of recombinant erythropoietin for protection of photoreceptor cells in a rat model of retinal detachment

PubMed Central

Xie, Z; Chen, F; Wu, X; Zhuang, C; Zhu, J; Wang, J; Ji, H; Wang, Y; Hua, X

2012-01-01

Purpose To elucidate the safety and efficacy of exogenous erythropoietin (EPO) for the protection of photoreceptor cells in a rat model of retinal detachment (RD). Methods Recombinant rat EPO (400 ng) was injected into the vitreous cavity of normal rats to observe the eye manifestations. Retinal function was assessed by flash electroretinograms. Histopathological examination of retinal tissue was performed at 14 days and 2 months after injection, respectively. To investigate the inhibitory effect of EPO on photoreceptor cell apoptosis in RD rats, 100, 200, or 400 ng EPO was injected into the vitreous cavity immediately after RD model establishment. Apoptosis of photoreceptor cells was determined at 3 days after injection. Caspase-3 activation was measured by western blot analysis and immunofluorescence, respectively, and the level of Bcl-XL expression was analyzed by western blot. Results Intravitreal injection of EPO 400 ng into normal rats had no significant impact on retinal function, morphology, or structure. Apoptosis of retinal photoreceptor cells apparently increased after RD and was significantly reduced following EPO treatment. The thickness of the outer nuclear layer in the RD+400 ng group was significantly thicker than that in other experimental RD groups both at 14 days and at 2 months after RD (P<0.05). Western blot and immunofluorescence analyses showed decreased caspase-3 activation and increased Bcl-XL expression following EPO treatment. Conclusion Intravitreal injection of EPO 400 ng is safe, and EPO may suppress caspase-3 activation and enhance Bcl-XL expression, resulting in inhibition of apoptosis and protection of photoreceptor cells. PMID:22020175

Diabetic macular edema treated with ranibizumab following bevacizumab failure in Israel (DERBI study).

PubMed

Ehrlich, Rita; Pokroy, Russell; Segal, Ori; Goldstein, Michaella; Pollack, Ayala; Hanhart, Joel; Barak, Yoreh; Kehat, Rinat; Shulman, Shiri; Vidne, Orit; Abu Ahmad, Wiessam; Chowers, Itay

2018-06-01

To evaluate the outcome of second-line intravitreal ranibizumab treatment in eyes with diabetic macular edema having persistent edema following initial therapy with intravitreal bevacizumab. Diabetic macular edema treated with ranibizumab following bevacizumab failure in Israel was a retrospective, multi-center study. Consecutive eyes with persistent diabetic macular edema following at least three previous intravitreal bevacizumab injections prior to intravitreal ranibizumab, at least three-monthly intravitreal ranibizumab injections and at least 12 months of follow-up were included. Data collected included demographics, ocular findings, diabetes control, details of intravitreal bevacizumab and ranibizumab injections, and visual and anatomical measurements before and after intravitreal ranibizumab treatment. In total, 202 eyes of 162 patients treated at 11 medical centers across Israel were included. Patients received a mean (±standard deviation) of 8.8 ± 4.9 intravitreal bevacizumab injections prior to the switch to intravitreal ranibizumab. A mean of 7.0 ± 2.7 intravitreal ranibizumab injections were given during the 12 months following the switch to intravitreal ranibizumab. The median central subfield retinal thickness (±interquartile range) by spectral-domain optical coherence tomography decreased from 436 ± 162 µm at baseline to 319 ± 113 µm at month 12 (p < 0.001). Median logMAR visual acuity (±interquartile range) improved from 0.40 ± 0.48 at baseline to 0.38 ± 0.40 at month 12 (p = 0.001). Linear regression suggested that higher number of intravitreal ranibizumab injections and higher pre-switch central subfield retinal thickness were associated with favorable visual outcome. Higher number of intravitreal bevacizumab injections and the presence of intraretinal fluid before the switch lessened the odds of favorable outcome. Switching from bevacizumab to ranibizumab in persistent diabetic macular edema was associated with anatomical improvement in the majority of eyes and ⩾2 lines of vision improvement in 22% of eyes.

Intraocular Delivery of miR-146 Inhibits Diabetes-Induced Retinal Functional Defects in Diabetic Rat Model.

PubMed

Zhuang, Pei; Muraleedharan, Chithra K; Xu, Shunbin

2017-03-01

Previously, we showed that microRNA-146 (miR-146) is a pivotal negative feedback regulator of multiple nuclear factor kappa-B (NF-κB) activation pathways in retinal endothelial cells (RECs). We hypothesized that miR-146 plays an important role in diabetic retinopathy (DR) by inhibiting diabetes-induced inflammatory response in the retina. The purpose of the current study is to test this hypothesis in vivo. Lentiviruses expressing rno-miR-146a, lenti-miR-146a, and negative control oligonucleotide with scrambled sequence, lenti-miR-neg ctl, were produced. Young male Sprague-Dawley rats were injected with a single dose of streptozotocin ([STZ] 65 mg/kg) to induce diabetes. One week after diabetes, animals were injected with lentivirus intravitreally (4 μl, ∼106 CFU/mL). Three months after diabetes, retinal microvascular leakage was tested by Evans blue assay; retinal function by electroretinogram (ERG). Total RNA and protein lysate were isolated from the retina for quantitative (q)RT-PCR and Western blot analyses. Lenti-miR-146a robustly transduced human retinal endothelial cells (HRECs) and increased the expression of miR-146a in vitro. In vivo, intravitreal injection of lenti-miR-146a increased the expression of miR-146a in the retina, while its key downstream target genes, including CARD10, IRAK1, and TRAF6, were downregulated. Intravitreal delivery of miR-146 inhibited diabetes-induced upregulation of NF-κB downstream gene, Intercellular Adhesion Molecule 1 (ICAM1), as well as microvascular leakage and retinal functional defects. Intravitreal delivery of miR-146 inhibited diabetes-induced NF-κB activation and retinal microvascular and neuronal functional defects in a diabetic rat model.

Hyaluronic Acid Graft Copolymers with Cleavable Arms as Potential Intravitreal Drug Delivery Vehicles.

PubMed

Borke, Tina; Najberg, Mathie; Ilina, Polina; Bhattacharya, Madhushree; Urtti, Arto; Tenhu, Heikki; Hietala, Sami

2018-01-01

Treatment of retinal diseases currently demands frequent intravitreal injections due to rapid clearance of the therapeutics. The use of high molecular weight polymers can extend the residence time in the vitreous and prolong the injection intervals. This study reports a water soluble graft copolymer as a potential vehicle for sustained intravitreal drug delivery. The copolymer features a high molecular weight hyaluronic acid (HA) backbone and poly(glyceryl glycerol) (PGG) side chains attached via hydrolysable ester linkers. PGG, a polyether with 1,2-diol groups in every repeating unit available for conjugation, serves as a detachable carrier. The influence of synthesis conditions and incubation in physiological media on the molecular weight of HA is studied. The cleavage of the PGG grafts from the HA backbone is quantified and polymer-from-polymer release kinetics are determined. The biocompatibility of the materials is tested in different cell cultures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Intravitreal Injection of Proinsulin-Loaded Microspheres Delays Photoreceptor Cell Death and Vision Loss in the rd10 Mouse Model of Retinitis Pigmentosa.

PubMed

Isiegas, Carolina; Marinich-Madzarevich, Jorge A; Marchena, Miguel; Ruiz, José M; Cano, María J; de la Villa, Pedro; Hernández-Sánchez, Catalina; de la Rosa, Enrique J; de Pablo, Flora

2016-07-01

The induction of proinsulin expression by transgenesis or intramuscular gene therapy has been shown previously to retard retinal degeneration in mouse and rat models of retinitis pigmentosa (RP), a group of inherited conditions that result in visual impairment. We investigated whether intraocular treatment with biodegradable poly (lactic-co-glycolic) acid microspheres (PLGA-MS) loaded with proinsulin has cellular and functional neuroprotective effects in the retina. Experiments were performed using the Pde6brd10 mouse model of RP. Methionylated human recombinant proinsulin (hPI) was formulated in PLGA-MS, which were administered by intravitreal injection on postnatal days (P) 14 to 15. Retinal neuroprotection was assessed at P25 by electroretinography, and by evaluating outer nuclear layer (ONL) cellular preservation. The attenuation of photoreceptor cell death by hPI was determined by TUNEL assay in cultured P22 retinas, as well as Akt phosphorylation by immunoblotting. We successfully formulated hPI PLGA-MS to deliver the active molecule for several weeks in vitro. The amplitude of b-cone and mixed b-waves in electroretinographic recording was significantly higher in eyes injected with hPI-PLGA-MS compared to control eyes. Treatment with hPI-PLGA-MS attenuated photoreceptor cell loss, as revealed by comparing ONL thickness and the number of cell rows in this layer in treated versus untreated retinas. Finally, hPI prevented photoreceptor cell death and increased AktThr308 phosphorylation in organotypic cultured retinas. Retinal degeneration in the rd10 mouse was slowed by a single intravitreal injection of hPI-PLGA-MS. Human recombinant proinsulin elicited a rapid and effective neuroprotective effect when administered in biodegradable microspheres, which may constitute a future potentially feasible delivery method for proinsulin-based treatment of RP.

On the retinal toxicity of intraocular glucocorticoids.

PubMed

Torriglia, Alicia; Valamanesh, Fatemeh; Behar-Cohen, Francine

2010-12-15

Corticosteroids are hormones involved in many physiological responses such as stress, immune modulation, protein catabolism and water homeostasis. The subfamily of glucocorticoids is used systemically in the treatment of inflammatory diseases or allergic reactions. In the eye, glucocorticoides are used to treat macular edema, inflammation and neovascularization. The most commonly used glucocorticoid is triamcinolone acetonide (TA). The pharmaceutical formulation of TA is not adapted for intravitreal administration but has been selected by ophthalmologists because its very low intraocular solubility provides sustained effect. Visual benefits of intraocular TA do not clearly correlate with morpho-anatomical improvements, suggesting potential toxicity. We therefore studied, non-common, but deleterious effects of glucocorticoids on the retina. We found that the intravitreal administration of TA is beneficial in the treatment of neovascularization because it triggers cell death of endothelial cells of neovessels by a caspase-independent mechanism. However, this treatment is toxic for the retina because it induces a non-apoptotic, caspase-independent cell death related to paraptosis, mostly in the retinal pigmented epithelium cells and the Müller cells. Copyright © 2010 Elsevier Inc. All rights reserved.

Short-term efficacy of intravitreal dobesilate in central serous chorioretinopathy

PubMed Central

2012-01-01

Purpose To report the anatomic and functional outcome of intravitreal dobesilate to treat recurrent central serous chorioretinopathy (CSC). Methods This is an interventional case report in which dobesilate was intravitreally injected in a case of recurrent CSC. Main measures included fundoscopy, Snellen visual acuity (VA) testing, fluorescein angiography and optical coherence tomography (OCT). Results We present anatomical and functional evidences, obtained as early as eleven days after the treatment, of the efficacy of intravitreal dobesilate, in the treatment of chronic CSC condition. The effect after intravitreal dobesilate injection for CSC might be related to the normalization of retinal architecture. Conclusions Intravitreal dobesilate may be an effective treatment option for recurrent CSC. PMID:22788836

SDF-1 is both necessary and sufficient to promote proliferative retinopathy

PubMed Central

Butler, Jason M.; Guthrie, Steven M.; Koc, Mehmet; Afzal, Aqeela; Caballero, Sergio; Brooks, H. Logan; Mames, Robert N.; Segal, Mark S.; Grant, Maria B.; Scott, Edward W.

2005-01-01

Diabetic retinopathy is the leading cause of blindness in working-age adults. It is caused by oxygen starvation in the retina inducing aberrant formation of blood vessels that destroy retinal architecture. In humans, vitreal stromal cell–derived factor–1 (SDF-1) concentration increases as proliferative diabetic retinopathy progresses. Treatment of patients with triamcinolone decreases SDF-1 levels in the vitreous, with marked disease improvement. SDF-1 induces human retinal endothelial cells to increase expression of VCAM-1, a receptor for very late antigen–4 found on many hematopoietic progenitors, and reduce tight cellular junctions by reducing occludin expression. Both changes would serve to recruit hematopoietic and endothelial progenitor cells along an SDF-1 gradient. We have shown, using a murine model of proliferative adult retinopathy, that the majority of new vessels formed in response to oxygen starvation originate from hematopoietic stem cell–derived endothelial progenitor cells. We now show that the levels of SDF-1 found in patients with proliferative retinopathy induce retinopathy in our murine model. Intravitreal injection of blocking antibodies to SDF-1 prevented retinal neovascularization in our murine model, even in the presence of exogenous VEGF. Together, these data demonstrate that SDF-1 plays a major role in proliferative retinopathy and may be an ideal target for the prevention of proliferative retinopathy. PMID:15630447

Characterization of intravitreally delivered capsid mutant AAV2-Cre vector to induce tissue-specific mutations in murine retinal ganglion cells.

PubMed

Langouet-Astrie, Christophe J; Yang, Zhiyong; Polisetti, Sraavya M; Welsbie, Derek S; Hauswirth, William W; Zack, Donald J; Merbs, Shannath L; Enke, Raymond A

2016-10-01

Targeted expression of Cre recombinase in murine retinal ganglion cells (RGCs) by viral vector is an effective strategy for creating tissue-specific gene knockouts for investigation of genetic contribution to RGC degeneration associated with optic neuropathies. Here we characterize dosage, efficacy and toxicity for sufficient intravitreal delivery of a capsid mutant Adeno-associated virus 2 (AAV2) vector encoding Cre recombinase. Wild type and Rosa26 (R26) LacZ mice were intravitreally injected with capsid mutant AAV2 viral vectors. Murine eyes were harvested at intervals ranging from 2 weeks to 15 weeks post-injection and were assayed for viral transduction, transgene expression and RGC survival. 10(9) vector genomes (vg) were sufficient for effective in vivo targeting of murine ganglion cell layer (GCL) retinal neurons. Transgene expression was observed as early as 2 weeks post-injection of viral vectors and persisted to 11 weeks. Early expression of Cre had no significant effect on RGC survival, while significant RGC loss was detected beginning 5 weeks post-injection. Early expression of viral Cre recombinase was robust, well-tolerated and predominantly found in GCL neurons suggesting this strategy can be effective in short-term RGC-specific mutation studies in experimental glaucoma models such as optic nerve crush and transection experiments. RGC degeneration with Cre expression for more than 4 weeks suggests that Cre toxicity is a limiting factor for targeted mutation strategies in RGCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pharmacokinetics and efficacy of intraocular flurbiprofen.

PubMed

Blazaki, S; Tsika, C; Tzatzarakis, M; Naoumidi, E; Tsatsakis, A; Tsatsanis, C; Tsilimbaris, Miltiadis K

2017-12-01

Intravitreal delivery of non-steroidal anti-inflammatory drugs could be an effective way to treat macular edema caused by posterior segment inflammation. In this study, we evaluated the intravitreal bioavailability and anti-inflammatory efficacy of flurbiprofen in rabbit eyes. For pharmacokinetics, 0.1 ml of 7.66 mg/ml flurbiprofen solution was injected intravitreally and vitreous drug levels were analyzed at specific time points using LC-MS technique. For efficacy, 100 ng lipopolysaccharide of E.coli was injected intravitreally in rabbits to induce inflammation. The animals were separated in three groups and received intraocular flurbiprofen, dexamethasone and PBS to serve as control. Complete ocular examination and total cell count in aqueous fluid were determined to evaluate the extent of inflammation. Eyes were then enucleated for histopathology analysis. The efficacy in the uveitis model was determined by clinical signs of inflammation, total leukocyte count and histology findings. No adverse events were observed during pharmacokinetic assessment. No signs of inflammation, hemorrhage or retina detachment were detected. The recovery of flurbiprofen from vitreous samples was 92.6%. The half-life of flurbiprofen was estimated to be 1.92 h with an elimination constant rate (K) of 0.36. Treatment with intraocular injections of flurbiprofen and dexamethasone significantly reduced total leukocyte count in a manner comparable to dexamethasone [reduction of 96.84% (p < 0.05) and 97.44% (p < 0.05), respectively]. Histologic studies demonstrated significantly less signs of ocular inflammation after flurbiprofen injection compared to control eyes. Flurbiprofen is effective in suppressing inflammation in this experimental uveitis model. In our experimental setting, intravitreal flurbiprofen seem to have a therapeutic result comparable to dexamethasone. However, the half-life of the drug remains short, necessitating further research to prolong its presence in the vitreous cavity.

High ocular CMV copies and mismatched receipts may predict poor visual prognosis in CMV retinitis patients following allogeneic haematopoietic stem cell transplantation.

PubMed

Zhang, Yuehong; Ruan, Xiangcai; Yang, Weizhong; Li, Ling; Xian, Zhuanhua; Feng, Qiting; Mo, Wenjian

2017-11-29

To summarize the clinical characteristics and potential factors affecting the visual outcomes in patients with cytomegalovirus retinitis following allogeneic haematopoietic stem cell transplantation (HSCT). This retrospective study enrolled 12 patients (19 eyes) with cytomegalovirus retinitis after HSCT at Guangzhou First People's Hospital in China between January 2013 and December 2014. Demographic and clinical characteristics, ocular manifestations and visual outcomes were evaluated by reviewing medical records at the Departments of Hematology and Ophthalmology. All patients were followed up at least 6 months after stopping antiviral therapy. The visual outcome was defined as improvement, stabilization and deterioration. The subjects were composed of 7 human leucocyte antigen-matched and 5 mismatched receipts. All patients received combined systemic and intravitreous antiviral therapy. Eleven eyes gained improved or stabilized visual acuity, while 8 eyes suffered deterioration. Eyes with cytomegalovirus load less than 1 × 10 4 copies/ml in vitreous accounted for higher rate in eyes with good visual prognosis than those with cytomegalovirus copies above 1 × 10 4 copies/ml (52.63% vs 5.26%, P < 0.001). Human leucocyte antigen-matched receipts gained better visual prognosis than those mismatched ones (47.37% vs10.53%, P < 0.05). The virus types, cytomegalovirus peak in the blood, involved retinal zone and size had no influence on the visual outcomes (all P > 0.05). High ocular cytomegalovirus copies and mismatched receipts may be potential adverse factors affecting visual outcomes in cytomegalovirus retinitis patients following allogeneic HSCT.

Safety evaluation of poly(lactic-co-glycolic acid)/poly(lactic-acid) microspheres through intravitreal injection in rabbits.

PubMed

Rong, Xianfang; Yuan, Weien; Lu, Yi; Mo, Xiaofen

2014-01-01

Poly(lactic-co-glycolic acid) (PLGA) and/or poly(lactic-acid) (PLA) microspheres are important drug delivery systems. This study investigated eye biocompatibility and safety of PLGA/PLA microspheres through intravitreal injection in rabbits. Normal New Zealand rabbits were randomly selected and received intravitreal administration of different doses (low, medium, or high) of PLGA/PLA microspheres and erythropoietin-loaded PLGA/PLA microspheres. The animals were clinically examined and sacrificed at 1, 2, 4, 8, and 12 weeks postadministration, and retinal tissues were prepared for analysis. Retinal reactions to the microspheres were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end staining and glial fibrillary acidic protein immunohistochemistry. Retinal structure changes were assessed by hematoxylin and eosin staining and transmission electron microscopy. Finally, retinal function influences were explored by the electroretinography test. Terminal deoxynucleotidyl transferase-mediated dUTP nick end staining revealed no apoptotic cells in the injected retinas; immunohistochemistry did not detect any increased glial fibrillary acidic protein expression. Hematoxylin and eosin staining and transmission electron microscopy revealed no micro- or ultrastructure changes in the retinas at different time points postintravitreal injection. The electroretinography test showed no significant influence of scotopic or photopic amplitudes. The results demonstrated that PLGA/PLA microspheres did not cause retinal histological changes or functional damage and were biocompatible and safe enough for intravitreal injection in rabbits for controlled drug delivery.

Occurrence of intraocular air bubbles during intravitreal injections for retinopathy of prematurity.

PubMed

Sukgen, Emine Alyamac; Gunay, Murat; Kocluk, Yusuf

2017-02-01

This study aims to present five cases with retinopathy of prematurity (ROP) who were found to have intraocular air bubbles after intravitreal injection (IVI) treatment. The medical records of 148 infants who underwent IVI for ROP were retrospectively reviewed and the ones who demonstrated post-injection intraocular air bubble formation were recruited. Of the 148 patients (31 babies received ranibizumab, 20 babies received aflibercept, 97 babies received bevacizumab), five were found to have intraocular air bubbles right after the IVI. Two infants received intravitreal ranibizumab and three received intravitreal bevacizumab injections. Although intraocular pressure increased temporarily, no intraocular sterile or infective reactions were observed in the postoperative period. The air bubble was found to resorb spontaneously within 72 h. The occurrence rate of the intravitreal air bubbles in our series was 3.37 % despite previously not been reported in the literature. Due to the intravitreal air injection risk, it is important to be more careful while preparing the intravitreal medication before treatment in premature babies.

ACTINOMYCES NEUII ENDOPHTHALMITIS AFTER INTRAVITREAL ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR INJECTION.

PubMed

Sahni, Sakshi; Watson, Randee Miller; Sheth, Veeral S

2017-01-01

To describe a case of acute endophthalmitis caused by Actinomyces neuii after intravitreal anti-vascular endothelial growth factor injection. Observational case report, review of published literature. A 67-year-old white man with wet age-related macular degeneration developed endophthalmitis secondary to A. neuii on the 10th day after intravitreal anti-vascular endothelial growth factor injection. Both anterior chamber and vitreous cultures were positive for A. neuii. He was treated successfully with intravitreal injection of vancomycin and ceftazidime. This is the first published report of culture-positive endophthalmitis caused by A. neuii after intravitreal injection.

In vitro induction of protein complexes between bevacizumab, VEGF-A¹⁶⁵ and heparin: explanation for deposits observed on endothelial veins in monkey eyes.

PubMed

Julien, Sylvie; Biesemeier, Antje; Schraermeyer, Ulrich

2013-04-01

By investigating the effects of intravitreal bevacizumab on retinal vessels of monkeys, we found that bevacizumab accumulated locally at high concentration within individual blood vessels. It formed electron-dense fibrous deposits between endothelial cells and erythrocytes or granulocytes inducing retinal vein thrombosis. To better characterise the observed deposits, we investigated in vitro whether these deposits result from a complex between bevacizumab, vascular endothelial growth factor (VEGF)-A(165) and heparin. Cynomolgus monkeys were intravitreally injected with 1.25 mg bevacizumab. The eyes were enucleated between 1 and 14 days after injection and investigated by electron microscopy and immunohistochemistry. Human umbilical vein endothelial cells (HUVEC) were incubated with bevacizumab, VEGF-A(165) and heparin at different concentrations. Treatments with ranibizumab served as control. Bevacizumab and ranibizumab were detected immunohistochemically using Cy-3 or immunogold labelled antibodies. Treated animals showed bevacizumab locally at high concentration within retinal blood vessels. Electron-dense deposits inside retinal vessels and between erythrocytes were detected in three out of four treated monkeys. In vitro, many globular aggregates heavily stained with anti-human IgG were only observed with equimolar amounts (240 nM) of bevacizumab and VEGF-A(165) and 0.2 U/ml heparin and not after ranibizumab treatment. The immunogold labelling specifically localised ultrastructurally the complexes formed between bevacizumab, VEGF-A(165) and heparin at the surfaces of HUVEC cells. Heparin promotes bevacizumab immune complex deposition on to endothelial cells. Our in vitro results could explain the presence of deposits observed on endothelial veins in monkey eyes intravitreally injected with bevacizumab.

Integrated results from the COPERNICUS and GALILEO studies.

PubMed

Pielen, Amelie; Clark, W Lloyd; Boyer, David S; Ogura, Yuichiro; Holz, Frank G; Korobelnik, Jean-Francois; Stemper, Brigitte; Asmus, Friedrich; Rittenhouse, Kay D; Ahlers, Christiane; Vitti, Robert; Saroj, Namrata; Zeitz, Oliver; Haller, Julia A

2017-01-01

To report on the efficacy and safety of intravitreal aflibercept in patients with macular edema secondary to central retinal vein occlusion (CRVO) in an integrated analysis of COPERNICUS and GALILEO. Patients were randomized to receive intravitreal aflibercept 2 mg every 4 weeks or sham injections until week 24. From week 24 to week 52, all intravitreal aflibercept-treated patients in both studies and sham-treated patients in COPERNICUS were eligible to receive intravitreal aflibercept based on prespecified criteria. In GALILEO, sham-treated patients continued to receive sham treatment through week 52. At week 24, mean gain in best-corrected visual acuity and mean reduction in central retinal thickness were greater for intravitreal aflibercept-treated patients compared with sham, consistent with individual trial results. At week 52, after 6 months of intravitreal aflibercept as-needed treatment in COPERNICUS, patients originally randomized to sham group experienced visual and anatomic improvements but did not improve to the extent of those initially treated with intravitreal aflibercept, while the sham group in GALILEO did not improve over week 24 mean best-corrected visual acuity scores. Ocular serious adverse events occurred in <10% of patients. This analysis of integrated data from COPERNICUS and GALILEO confirmed that intravitreal aflibercept is an effective treatment for macular edema following CRVO.

Integrated results from the COPERNICUS and GALILEO studies

PubMed Central

Pielen, Amelie; Clark, W Lloyd; Boyer, David S; Ogura, Yuichiro; Holz, Frank G; Korobelnik, Jean-Francois; Stemper, Brigitte; Asmus, Friedrich; Rittenhouse, Kay D; Ahlers, Christiane; Vitti, Robert; Saroj, Namrata; Zeitz, Oliver; Haller, Julia A

2017-01-01

Objectives To report on the efficacy and safety of intravitreal aflibercept in patients with macular edema secondary to central retinal vein occlusion (CRVO) in an integrated analysis of COPERNICUS and GALILEO. Patients and methods Patients were randomized to receive intravitreal aflibercept 2 mg every 4 weeks or sham injections until week 24. From week 24 to week 52, all intravitreal aflibercept-treated patients in both studies and sham-treated patients in COPERNICUS were eligible to receive intravitreal aflibercept based on prespecified criteria. In GALILEO, sham-treated patients continued to receive sham treatment through week 52. Results At week 24, mean gain in best-corrected visual acuity and mean reduction in central retinal thickness were greater for intravitreal aflibercept-treated patients compared with sham, consistent with individual trial results. At week 52, after 6 months of intravitreal aflibercept as-needed treatment in COPERNICUS, patients originally randomized to sham group experienced visual and anatomic improvements but did not improve to the extent of those initially treated with intravitreal aflibercept, while the sham group in GALILEO did not improve over week 24 mean best-corrected visual acuity scores. Ocular serious adverse events occurred in <10% of patients. Conclusion This analysis of integrated data from COPERNICUS and GALILEO confirmed that intravitreal aflibercept is an effective treatment for macular edema following CRVO. PMID:28883712

Effect of an intravitreal cyclosporine implant on experimental uveitis in horses.

PubMed

Gilger, B C; Malok, E; Stewart, T; Horohov, D; Ashton, P; Smith, T; Jaffe, G J; Allen, J B

2000-10-31

The purpose of this study was to determine the effects of an intravitreal device releasing cyclosporine A (CsA) on recurrent inflammatory episodes in experimental uveitis. Nine normal horses were immunized peripherally with H37RA-mTB antigen twice, and then received 25 microg of H37RA-mTB antigen intravitreally in the right eye and an equal volume of balanced salt solution intravitreally in the left eye. Two weeks later, the animals randomly received either a CsA or a polymer implant (without CsA) in both eyes 1 week following implantation of the devices, 25 microg of H37RA-mTB antigen was reinjected into the right eye of each animal. Clinical signs of ophthalmic inflammation were graded following injections and implantation. The animals from each group were euthanized at 3, 14, and 28 days following the second injection. Aqueous and vitreous humor protein concentrations were measured. The presence, number, and type (CD4, 5 and 8) of infiltrating inflammatory cells and amount of tissue destruction were determined. Total RNA was isolated and quantitative reverse transcriptase-polymerase chain reaction was performed for equine specific interleukin (IL) 2 and 4, interferon-gamma (IFN gamma) and beta-actin. In addition, aqueous and vitreous humor and peripheral blood were collected at the termination of the experiments and analyzed for CsA concentration by HPLC. Within 4h of the first intravitreal H37RA-mTB antigen injection, each animal developed epiphora, blepharospasm, mild corneal edema, aqueous flare, myosis, and vitreous opacity. The severity of signs peaked 48 to 72 h after injection and subsequently decreased back to normal within 14 days. Following the second injection, clinical signs in the eyes with the CsA device were less severe and significantly shorter in duration than signs with the polymer only implant eyes. Aqueous and vitreous humor protein levels, infiltrating cell numbers, total number of T-lymphocytes, and levels of IL-2 and IFN gamma-mRNA were significantly less in eyes with the CsA implant compared to eyes with the polymer only. CsA implants did not completely eliminate the development of a second ('recurrent') experimental inflammatory episode in these horses. However, the duration and severity of inflammation, cellular infiltration, tissue destruction, and pro-inflammatory cytokines RNA transcript levels were significantly less in those eyes implanted with the CsA device.

Photoreceptor neuroprotection in RCS rats via low-dose intravitreal sustained-delivery of fluocinolone acetonide.

PubMed

Glybina, Inna V; Kennedy, Alexander; Ashton, Paul; Abrams, Gary W; Iezzi, Raymond

2009-10-01

To study the neuroprotective effects of intravitreal fluocinolone acetonide (FA) in Royal College of Surgeons (RCS) rats. Five-week-old RCS rats were divided into four groups: 0.5 microg/d FA-loaded intravitreal drug-delivery implant (IDDI); 0.2 microg/d FA-loaded IDDI; inactive IDDI; and nonsurgical control. Electroretinography (ERG) and intraocular pressure (IOP) measurements were performed before surgery and weekly thereafter. Thicknesses of the retinal outer (ONL) and inner (INL) nuclear layers were evaluated at 9 weeks of age. ED-1-labeled activated microglia were counted. Total microglial cell counts were made by using Iba-1 antibody labeling. At 9 weeks, control groups demonstrated an 80% reduction in ERG amplitudes (P < 0.001 for both groups). FA-treated groups demonstrated no statistically significant attenuation of ERG amplitudes at the end of the study, compared with the initial ERGs. Intraocular pressure (IOP) remained normal in all groups. ONL thickness in FA 0.2 microg/d-treated eyes was 2.1 +/- 0.5 times greater than in nonsurgical eyes (P < 0.001) and 3.4 +/- 0.7 times greater than in inactive IDDI-treated eyes (P < 0.0001). In FA 0.5 microg/d-treated eyes, ONL thickness was 1.5 +/- 0.1 times higher than in nonsurgical controls (P < 0.05) and 2.4 +/- 0.4 times higher than in inactive IDDI-treated eyes (P < 0.01). INL thickness was not different among groups. FA-treated eyes demonstrated significantly fewer activated microglia (P < 0.001) and overall number of microglia in the photoreceptor and outer debris zone layers (P < 0.001), compared with control groups. Chronic intravitreal infusion of FA is neuroprotective in RCS rats, preserves ONL morphology and ERG amplitudes and reduces retinal neuroinflammation. These findings may have a therapeutic role in human photoreceptor cell degenerations.

Blocking IL-17A Alleviates Diabetic Retinopathy in Rodents.

PubMed

Qiu, Ao-Wang; Liu, Qing-Huai; Wang, Jun-Ling

2017-01-01

Interleukin (IL)-17A, a proinflammatory cytokine, has been implicated in several autoimmune diseases. However, it is unclear whether IL-17A is involved in diabetic retinopathy (DR), one of the most serious complications of autoimmune diabetes. This study aimed to demonstrate that IL-17A exacerbates DR by affecting retinal Müller cell function. High glucose (HG)-treated rat Müller cell line (rMC-1) was exposed to IL-17A, anti-IL-17A-neutralizing monoclonal antibody (mAb) or/and anti-IL-17 receptor (R)A-neutralizing mAb for 24 h. For in vivo study, DR was induced by intraperitoneal injections of streptozotocin (STZ). DR model mice were treated with anti-IL-17A mAb or anti-IL-17RA mAb in the vitreous cavity. Mice that were prepared for retinal angiography were sacrificed two weeks after intravitreal injection, while the rest were sacrificed two days after intravitreal injection. IL-17A production and IL-17RA expression were increased in both HG-treated rMC-1 and DR retina. HG induced rMC-1 activation and dysfunction, as determined by the increased GFAP, VEGF and glutamate levels as well as the downregulated GS and EAAT1 expression. IL-17A exacerbated the HG-induced rMC-1 functional disorders, whereas either anti-IL-17A mAb or anti-IL-17RA mAb alleviated the HG-induced rMC-1 disorders. Intravitreal injections with anti-IL-17A mAb or anti-IL-17RA mAb in DR model mice reduced Müller cell dysfunction, vascular leukostasis, vascular leakage, tight junction protein downregulation and ganglion cell apoptosis in the retina. IL-17A aggravates DR-like pathology at least partly by impairing retinal Müller cell function. Blocking IL-17A is a potential therapeutic strategy for DR. © 2017 The Author(s)Published by S. Karger AG, Basel.

SCORE Study Report 7: incidence of intravitreal silicone oil droplets associated with staked-on vs luer cone syringe design.

PubMed

Scott, Ingrid U; Oden, Neal L; VanVeldhuisen, Paul C; Ip, Michael S; Blodi, Barbara A; Antoszyk, Andrew N

2009-11-01

To evaluate the incidence of intravitreal silicone oil (SO) droplets associated with intravitreal injections using a staked-on vs luer cone syringe design in the SCORE (Standard Care vs COrticosteroid in REtinal Vein Occlusion) Study. Prospective, randomized, phase III clinical trial. The incidence of intravitreal SO was compared among participants exposed to the staked-on syringe design, the luer cone syringe design, or both of the syringe designs in the SCORE Study, which evaluated intravitreal triamcinolone acetonide injection(s) for vision loss secondary to macular edema associated with central or branch retinal vein occlusion. Injections were given at baseline and 4-month intervals, based on treatment assignment and study-defined retreatment criteria. Because intravitreal SO was observed following injections in some participants, investigators were instructed, on September 22, 2006, to look for intravitreal SO at all study visits. On November 1, 2007, the luer cone syringe design replaced the staked-on syringe design. A total of 464 participants received a total of 1,205 injections between November 4, 2004 and February 28, 2009. Intravitreal SO was noted in 141 of 319 participants (44%) exposed only to staked-on syringes, 11 of 87 (13%) exposed to both syringe designs, and 0 of 58 exposed only to luer cone syringes (P < .0001). Among participants with first injections after September 22, 2006, intravitreal SO was noted in 65 of 114 (57%) injected only with staked-on syringes compared with 0 of 58 injected only with luer cone syringes. Differential follow-up is unlikely to explain these results. In the SCORE Study, luer cone syringe design is associated with a lower frequency of intravitreal SO droplet occurrence compared with the staked-on syringe design, likely attributable to increased residual space in the needle hub with the luer cone design.

Retinal Astrocytes and GABAergic Wide-Field Amacrine Cells Express PDGFRα: Connection to Retinal Ganglion Cell Neuroprotection by PDGF-AA.

PubMed

Takahama, Shokichi; Adetunji, Modupe O; Zhao, Tantai; Chen, Shan; Li, Wei; Tomarev, Stanislav I

2017-09-01

Our previous experiments demonstrated that intravitreal injection of platelet-derived growth factor-AA (PDGF-AA) provides retinal ganglion cell (RGC) neuroprotection in a rodent model of glaucoma. Here we used PDGFRα-enhanced green fluorescent protein (EGFP) mice to identify retinal cells that may be essential for RGC protection by PDGF-AA. PDGFRα-EGFP mice expressing nuclear-targeted EGFP under the control of the PDGFRα promoter were used. Localization of PDGFRα in the neural retina was investigated by confocal imaging of EGFP fluorescence and immunofluorescent labeling with a panel of antibodies recognizing different retinal cell types. Primary cultures of mouse RGCs were produced by immunopanning. Neurobiotin injection of amacrine cells in a flat-mounted retina was used for the identification of EGFP-positive amacrine cells in the inner nuclear layer. In the mouse neural retina, PDGFRα was preferentially localized in the ganglion cell and inner nuclear layers. Immunostaining of the retina demonstrated that astrocytes in the ganglion cell layer and a subpopulation of amacrine cells in the inner nuclear layer express PDGFRα, whereas RGCs (in vivo or in vitro) did not. PDGFRα-positive amacrine cells are likely to be Type 45 gamma-aminobutyric acidergic (GABAergic) wide-field amacrine cells. These data indicate that the neuroprotective effect of PDGF-AA in a rodent model of glaucoma could be mediated by astrocytes and/or a subpopulation of amacrine cells. We suggest that after intravitreal injection of PDGF-AA, these cells secrete factors protecting RGCs.

Rabbit as an animal model for intravitreal pharmacokinetics: Clinical predictability and quality of the published data.

PubMed

Del Amo, Eva M; Urtti, Arto

2015-08-01

Intravitreal administration is the method of choice in drug delivery to the retina and/or choroid. Rabbit is the most commonly used animal species in intravitreal pharmacokinetics, but it has been criticized as being a poor model of human eye. The critique is based on some anatomical differences, properties of the vitreous humor, and observed differences in drug concentrations in the anterior chamber after intravitreal injections. We have systematically analyzed all published information on intravitreal pharmacokinetics in the rabbit and human eye. The analysis revealed major problems in the design of the pharmacokinetic studies. In this review we provide advice for study design. Overall, the pharmacokinetic parameters (clearance, volume of distribution, half-life) in the human and rabbit eye have good correlation and comparable absolute values. Therefore, reliable rabbit-to-man translation of intravitreal pharmacokinetics should be feasible. The relevant anatomical and physiological parameters in rabbit and man show only small differences. Furthermore, the claimed discrepancy between drug concentrations in the human and rabbit aqueous humor is not supported by the data analysis. Based on the available and properly conducted pharmacokinetic studies, the differences in the vitreous structure in rabbits and human patients do not lead to significant pharmacokinetic differences. This review is the first step towards inter-species translation of intravitreal pharmacokinetics. More information is still needed to dissect the roles of drug delivery systems, disease states, age and ocular manipulation on the intravitreal pharmacokinetics in rabbit and man. Anyway, the published data and the derived pharmacokinetic parameters indicate that the rabbit is a useful animal model in intravitreal pharmacokinetics. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Management of diabetic macular edema with intravitreal dexamethasone implants: Expert recommendations using a Delphi-based approach.

PubMed

Giovannini, Alfonso; Parravano, Mariacristina; Ricci, Federico; Bandello, Francesco

2018-06-01

Despite being approved and effective, steroids, and especially dexamethasone intravitreal implants, still have a poorly-defined role in management of diabetic macular edema. In order to overcome some of the limitations in current recommendations, a group of experts met to define consensus on some of the most controversial issues on the use of dexamethasone intravitreal implants in daily management of diabetic macular edema. A Delphi-based approach was utilized to develop clinically relevant statements applicable to routine treatment settings. A Steering Committee composed of four experts formulated 30 relevant statements, which were voted upon by a panel of 40 ophthalmologists/retinal specialists from across Italy. Dexamethasone intravitreal implants were considered to be a valid first-line alternative to treatment with an anti-vascular endothelial growth factor agent and should be the first choice in pseudophakic and vitrectomized patients. A Pro Re Nata regimen was felt to be appropriate for retreatment with dexamethasone intravitreal implants while a 6-month waiting period was not considered suitable. Among steroid treatments, dexamethasone intravitreal implants were considered to have the best ocular tolerability. In patients with persistent macular edema after the loading-phase treatment with an anti-vascular endothelial growth factor, consensus was reached that clinicians should consider switching therapy to dexamethasone intravitreal implants. Moreover, dexamethasone intravitreal implants can reduce the treatment burden for individuals who are not able to cope with the more intensive treatment regimen required by anti-vascular endothelial growth factor therapy. While further studies are needed, this survey provides some key recommendations for clinicians treating diabetic macular edema that may be useful when choosing dexamethasone intravitreal implants in daily practice.

Management of a case of Candida albicans endogenous endophthalmitis with intravitreal caspofungin

PubMed Central

Yadav, Harshali Manish; Thomas, Boben; Thampy, Cherian; Panaknti, Tandava Krishnan

2017-01-01

We report a case of Candida albicans endogenous endophthalmitis treated with intravitreal caspofungin. The patient was a known case of acute lymphoblastic leukemia on chemotherapy and presented to us with features suggestive of endogenous endophthalmitis. He was treated initially with intravenous (IV) caspofungin and intravitreal amphotericin B. Patients condition worsened after IV caspofungin was replaced by amphotericin B necessitating a core vitrectomy. The patient was given the option of off-label caspofungin intravitreal injection for which the patient consented. There was a gradual improvement in the clinical picture. The situation worsened after the injections were stopped necessitating a revitrectomy. The study demonstrates the clinical efficacy of intravitreal caspofungin for the first time in human eyes. PMID:28643723

Aortoduodenal fistula in a patient on intravitreal bevacizumab injections: a case report.

PubMed

Pepper, Amber N; Valenzuela, Mauricio O; Oller, Kellee L

2015-01-01

An 88-year-old woman on long-term intravitreal bevacizumab presented with acute gastrointestinal hemorrhage. She was stabilized and underwent nonrevealing upper endoscopy. She continued to require intermittent blood transfusions, and resulting computed tomography of the abdomen revealed an aortoduodenal fistula. The patient was undergoing treatment for her macular degeneration with intravitreal bevacizumab, an angiogenesis inhibitor frequently used to treat solid organ malignancies. Systemic administration has been associated with serious adverse events, including gastrointestinal hemorrhage, perforation, and fistula formation. Intravitreal bevacizumab has been used off-label to treat macular degeneration, but data on the safety of this therapy are limited. Given her lack of other risk factors, the authors postulate a potential association between intravitreal bevacizumab and aortoduodenal fistula formation in this patient.

Assistive Device for Efficient Intravitreal Injections.

PubMed

Ullrich, Franziska; Michels, Stephan; Lehmann, Daniel; Pieters, Roel S; Becker, Matthias; Nelson, Bradley J

2016-08-01

Intravitreal therapy is the most common treatment for many chronic ophthalmic diseases, such as age-related macular degeneration. Due to the increasing worldwide demand for intravitreal injections, there exists a need to render this medical procedure more time- and cost-efficient while increasing patient safety. The authors propose a medical assistive device that injects medication intravitreally. Compared to the manual intravitreal injection procedure, an automated device has the potential to increase safety for patients, decrease procedure times, allow for integrated data storage and documentation, and reduce costs for medical staff and expensive operating rooms. This work demonstrates the development of an assistive injection system that is coarsely positioned over the patient's head by the human operator, followed by automatic fine positioning and intravitreal injection through the pars plana. Several safety features, such as continuous eye tracking and iris recognition, have been implemented. The functioning system is demonstrated through ex vivo experiments with porcine eyes. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:752-762.]. Copyright 2016, SLACK Incorporated.

A survey of UK practice patterns in the delivery of intravitreal injections.

PubMed

Samia-Aly, Emma; Cassels-Brown, Andrew; Morris, Daniel S; Stancliffe, Rachel; Somner, John E A

2015-07-01

To assess UK practice patterns related to the prescription of antibiotics before, during and after intravitreal injections, the location where injections are carried out and the qualifications of those administering the injections. Every ophthalmology unit featured in the Royal College of Ophthalmologists (UK) training directory was contacted. A healthcare professional involved in giving intravitreal injections at each institution completed a questionnaire regarding local practice patterns. A response rate of 85% (115/136) was achieved. Seventy four percent of hospitals (85/115) gave take home antibiotics post intravitreal injection. Twenty three percent (26/115) of hospitals employed non-medical healthcare professionals to administer injections and 83% (96/115) administered intravitreal injections in a dedicated clean room as opposed to an operating theatre. Practice patterns for intravitreal injection vary considerably. Guidelines alone do not appear to be effective in reducing practices which are considered wasteful and other approaches need to be developed. © 2015 The Authors Ophthalmic & Physiological Optics © 2015 The College of Optometrists.

Juvenile X-linked retinoschisis responsive to intravitreal corticosteroids.

PubMed

Ansari, Waseem H; Browne, Andrew W; Singh, Rishi P

2017-04-01

To report the case of an adult male with X-linked retinoschisis (XLRS) who presented with cystoid macular edema (CME) that responded consistently to treatment with intravitreal steroids. A 39 year old male with unilateral presentation of CME after repair of a retinal detachment secondary to XLRS responded initially to an injection of intravitreal triamcinolone acetonide (IVTA). Central subfield thickness on OCT was reduced. Three months later, the CME recurred and he was unresponsive to topical treatment so repeat IVTA was given, and the CME once again was reduced dramatically. After the next recurrence, intravitreal dexamethasone implant treatment was initiated and successful at treating recurrences in 3 month intervals for 5 additional injections. Finally, an intravitreal fluocinolone acetonide implant was surgically placed with control of CME. Corticosteroids have never been reported to be effective in CME related to XLRS. Here, we document a case of a man who successfully had decrease of intraretinal fluid and schisis with treatment of intravitreal corticosteroids as demonstrated by spectral domain optical coherence tomography.

The Relationship Between the Renin-Angiotensin-Aldosterone System and NMDA Receptor-Mediated Signal and the Prevention of Retinal Ganglion Cell Death.

PubMed

Kobayashi, Mamoru; Hirooka, Kazuyuki; Ono, Aoi; Nakano, Yuki; Nishiyama, Akira; Tsujikawa, Akitaka

2017-03-01

Excitotoxicity, which is due to glutamate-induced toxic effects on the retinal ganglion cell (RGC), is one of several mechanisms of RGC loss. The renin-angiotensin-aldosterone system (RAAS) has also been implicated in RGC death. Therefore, it is important to determine the exact relationship between the RAAS and N-methyl-d-aspartate (NMDA) receptor-mediated signal in order to prevent RGC death. N-methyl-d-aspartate or aldosterone was injected into the vitreous body. After intravitreal injection of NMDA or aldosterone, animals were treated with spironolactone or memantine. Retinal damage was evaluated by measuring the number of RGCs at 4 weeks after local administration of aldosterone or at 2 weeks after local administration of NMDA. Vitreous humor levels of aldosterone were measured using enzyme immunoassay kits. A significantly decreased number of RGCs were observed after intravitreal injection of NMDA. Although spironolactone did not show any neuroprotective effects, memantine significantly reduced NMDA-induced degeneration in the retina. Furthermore, a significant decrease in the number of RGCs was observed after an intravitreal injection of aldosterone. While memantine did not exhibit any neuroprotective effects, spironolactone caused a significant reduction in the aldosterone-induced degeneration in the retina. There was no change in the aldosterone concentration in the vitreous humor after an NMDA injection. Our findings indirectly show that there is no relationship between the RAAS and NMDA receptor-mediated signal with regard to RGC death.

Topical application of a G-Quartet aptamer targeting nucleolin attenuates choroidal neovascularization in a model of age-related macular degeneration.

PubMed

Leaderer, Derek; Cashman, Siobhan M; Kumar-Singh, Rajendra

2015-11-01

Choroidal neovascularization (CNV) associated with the 'wet' form of age related macular degeneration (AMD) is one of the most common causes of central vision loss among the elderly. The 'wet' form of AMD is currently treated by intravitreal delivery of anti-VEGF agents. However, intravitreal injections are associated with complications and long-term inhibition of VEGF leads to macular atrophy. Thus, there is currently an unmet need for the development of therapies for CNV that target molecules other than VEGF. Here, we describe nucleolin as a novel target for the 'wet' form of AMD. Nucleolin was found on the surface of endothelial cells that migrate from the choroid into the subretinal space in the laser-induced model of 'wet' AMD. AS1411 is a previously described G-quartet oligonucleotide that has been shown to bind nucleolin. We found that AS1411 inhibited the formation of tubes by human umbilical vein endothelial cells (HUVECs) by approximately 27.4% in vitro. AS1411 co-localized with the site of laser induced CNV in vivo. Intravitreally injected AS1411 inhibited laser-induced CNV by 37.6% and attenuated infiltration of macrophages by 40.3%. Finally, topical application of AS1411 led to a 43.4% reduction in CNV. Our observations have potential implications for the development of therapies for CNV and specifically for the 'wet' form of AMD. Copyright © 2015 Elsevier Ltd. All rights reserved.

MicroRNA-188-5p regulates contribution of bone marrow-derived cells to choroidal neovascularization development by targeting MMP-2/13.

PubMed

Hou, Huiyuan; Gao, Fan; Liang, Hongliang; Lv, Yang; Li, Manhong; Yao, Libo; Zhang, Jian; Dou, Guorui; Wang, Yusheng

2018-06-14

Our previous investigations have shown that bone marrow-derived cells (BMCs), including mesenchymal stem cells (MSCs), contribute to the development of choroidal neovascularization (CNV) as sources of cells and angiogenic factors. Two main steps for circulating BMCs to integrate into CNV lesions are extracellular matrix remodeling and consequential cell migration. MicroRNAs (miRNAs) were found to be involved in CNV development; however, little is known about whether miRNAs regulate the contribution of BMCs to CNV. In the present study, we found that the expression of miR-188-5p was decreased in cultured hypoxic MSCs and BMCs within laser-induced CNV in mice. Matrix metalloproteinase 2 (MMP-2) and MMP-13 were both discovered as targets of miR-188-5p by bioinformatics predictions and dual-luciferase reporter system. Accordingly, increased expression of MMP-2/13 was found in hypoxic MSCs and BMCs in CNV lesions. Furthermore, miR-188-5p mimic transfection caused downregulation of MMP-2/13 in hypoxic MSCs and decreased tube formation of co-cultured vascular endothelial cells. Intravitreal injections of a miR-188-5p agomir attenuated the severity of CNV and inhibited the migration of BMCs into CNV lesions in mice. Our study suggests that miR-188-5p regulates the contribution of BMCs to CNV development by targeting MMP-2/13-mediated extracellular matrix degeneration, and miR-188-5p serves as a therapeutic target to treat CNV-related diseases. Copyright © 2018. Published by Elsevier Ltd.

Intravitreal clindamycin and dexamethasone for toxoplasmic retinochoroiditis.

PubMed

Kishore, K; Conway, M D; Peyman, G A

2001-01-01

To present a new method for the management of toxoplasmic retinochoroiditis (TRC). The patients were females ranging in age from 10 to 61 years (average 26.5). Four eyes of 4 patients were treated with intravitreal injections of 1.0 mg clindamycin in 0.1 mL and 1.0 mg of dexamethasone in 0.1 mL. The injections were given under general or peribulbar anesthesia. Three patients continued one systemic drug. Follow-up ranged from 11 to 26 months (mean 17.5). A favorable response was noted in each eye within two weeks after the intravitreal injections. All patients required 2 to 4 intravitreal injections in the affected eye for the control of TRC. Visual acuity improved in each eye. The disc and macula were preserved in all eyes. Recurrence was noted in one case, which responded to a repeated intravitreal injection of clindamycin and dexamethasone. Intravitreal injections of clindamycin and dexamethasone are well tolerated and may offer an additional strategy to treat TRC in patients who are unable to afford or tolerate systemic therapy, or whose disease progresses despite systemic therapy.

Short-term outcome after intravitreal ranibizumab injections for the treatment of retinopathy of prematurity.

PubMed

Castellanos, María Ana Martínez; Schwartz, Shulamit; García-Aguirre, Gerardo; Quiroz-Mercado, Hugo

2013-07-01

To evaluate ocular outcome in premature infants treated with intravitreal ranibizumab injections for retinopathy of prematurity (ROP) over a period of 3 years. An interventional case series. Premature infants with high-risk prethreshold or threshold ROP with plus disease received an off label monotherapy with intravitreal injections of ranibizumab. The primary outcome was treatment success defined as regression of neovascularisation (NV) and absence of recurrence. The secondary outcomes were ocular and systemic adverse events and visual acuity. Six eyes were included in the study and treated with intravitreal injections of ranibizumab. All showed complete resolution of NV after a single injection. The anti-angiogenic intravitreal injections allowed for continued normal vessel growth into the peripheral retina, without any signs of disease recurrence or progression during the follow up period. No ocular or systemic adverse effects were observed. Three years of follow up in a small series suggest that intravitreal ranibizumab injections for ROP result in apparently preserved ocular outcome. Further large scale studies are needed to address the long-term safety and efficacy.

Intravitreal triamcinolone acetonide injections in the treatment of retinal vein occlusions.

PubMed

Roth, Daniel B; Cukras, Catherine; Radhakrishnan, Ravi; Feuer, William J; Yarian, David L; Green, Stuart N; Wheatley, Harold M; Prenner, Jonathan

2008-01-01

To report the visual acuity response after intravitreal triamcinolone injection in patients with macular edema due to retinal vein occlusions. Retrospective nonrandomized interventional series of 172 consecutive patients with macular edema due to retinal vein occlusions who were treated with intravitreal triamcinolone acetonide injection. Patients underwent Snellen visual acuity testing and ophthalmoscopic examination at baseline and 1, 3, 6, and 12 months after intravitreal triamcinolone acetonide injection. All subtypes of retinal vein occlusions showed significant improvements in mean visual acuity 1 month after injection. This improvement in visual acuity was maintained over the 12-month period for all but the central retinal vein occlusion group. Seventy-one (41.3%) of the 172 patients received more than one intravitreal triamcinolone injection for unresolved or recurrent macular edema. This study demonstrates a benefit associated with intravitreal triamcinolone acetonide injection for retinal vein occlusions that was maintained by patients with branch retinal vein occlusions and hemiretinal vein occlusions over a 12-month period. Visual acuity improvement was not maintained in patients with central retinal vein occlusions with this course of treatment.

Treatment of cytomegalovirus retinitis with intravitreal ganciclovir. Long-term results.

PubMed

Cantrill, H L; Henry, K; Melroe, N H; Knobloch, W H; Ramsay, R C; Balfour, H H

1989-03-01

Long-term management of cytomegalovirus (CMV) retinitis by intravitreal injection of ganciclovir was evaluated in ten patients with acquired immune deficiency syndrome (AIDS). Patients were unable to tolerate systemic ganciclovir because of severe neutropenia (8 cases), catheter-induced sepsis (1 case), or the need to continue therapy for human immunodeficiency virus (HIV) with zidovudine (ZDV) (1 case). All patients had a favorable response to initial treatment. Cytomegalovirus retinitis progressed in four fellow eyes in which treatment was deferred. Vision improved or remained stable in all but one eye. Patients were followed for a mean of 4 months and received an average of 16.6 intravitreal injections in each eye. Relapse occurred late in the course while on maintenance treatment in five eyes (33%). There was no evidence of toxicity from repeated intravitreal injections. Treatment was very well tolerated. The only severe complication in a total of 249 injections was a single case of Staphylococcus epidermidis endophthalmitis which responded to intravitreal antibiotic treatment. Intravitreal ganciclovir is an effective alternative to systemic ganciclovir in those patients with severe neutropenia and in those patients who desire to remain on systemic ZDV.

CMV retinitis screening and treatment in a resource-poor setting: three-year experience from a primary care HIV/AIDS programme in Myanmar

PubMed Central

2011-01-01

Background Cytomegalovirus retinitis is a neglected disease in resource-poor settings, in part because of the perceived complexity of care and because ophthalmologists are rarely accessible. In this paper, we describe a pilot programme of CMV retinitis management by non-ophthalmologists. The programme consists of systematic screening of all high-risk patients (CD4 <100 cells/mm3) by AIDS clinicians using indirect ophthalmoscopy, and treatment of all patients with active retinitis by intravitreal injection of ganciclovir. Prior to this programme, CMV retinitis was not routinely examined for, or treated, in Myanmar. Methods This is a retrospective descriptive study. Between November 2006 and July 2009, 17 primary care AIDS clinicians were trained in indirect ophthalmoscopy and diagnosis of CMV retinitis; eight were also trained in intravitreal injection. Evaluation of training by a variety of methods documented high clinical competence. Systematic screening of all high-risk patients (CD4 <100 cells/mm3) was carried out at five separate AIDS clinics throughout Myanmar. Results A total of 891 new patients (1782 eyes) were screened in the primary area (Yangon); the majority of patients were male (64.3%), median age was 32 years, and median CD4 cell count was 38 cells/mm3. CMV retinitis was diagnosed in 24% (211/891) of these patients. Bilateral disease was present in 36% of patients. Patients with active retinitis were treated with weekly intravitreal injection of ganciclovir, with patients typically receiving five to seven injections per eye. A total of 1296 injections were administered. Conclusions A strategy of management of CMV retinitis at the primary care level is feasible in resource-poor settings. With appropriate training and support, CMV retinitis can be diagnosed and treated by AIDS clinicians (non-ophthalmologists), just like other major opportunistic infections. PMID:21843351

Randomized trial of anesthetic methods for intravitreal injections.

PubMed

Blaha, Gregory R; Tilton, Elisha P; Barouch, Fina C; Marx, Jeffrey L

2011-03-01

To compare the effectiveness of four different anesthetic methods for intravitreal injection. Twenty-four patients each received four intravitreal injections using each of four types of anesthesia (proparacaine, tetracaine, lidocaine pledget, and subconjunctival injection of lidocaine) in a prospective, masked, randomized block design. Pain was graded by the patient on a 0 to 10 scale for both the anesthesia and the injection. The average combined pain scores for both the anesthesia and the intravitreal injection were 4.4 for the lidocaine pledget, 3.5 for topical proparacaine, 3.8 for the subconjunctival lidocaine injection, and 4.1 for topical tetracaine. The differences were not significant (P = 0.65). There were also no statistical differences in the individual anesthesia or injection pain scores. Subconjunctival lidocaine injection had the most side effects. Topical anesthesia is an effective method for limiting pain associated with intravitreal injections.

Intravitreal Aflibercept Injection in Eyes With Substantial Vision Loss After Laser Photocoagulation for Diabetic Macular Edema: Subanalysis of the VISTA and VIVID Randomized Clinical Trials.

PubMed

Wykoff, Charles C; Marcus, Dennis M; Midena, Edoardo; Korobelnik, Jean-François; Saroj, Namrata; Gibson, Andrea; Vitti, Robert; Berliner, Alyson J; Williams Liu, Zinaria; Zeitz, Oliver; Metzig, Carola; Schmelter, Thomas; Heier, Jeffrey S

2016-12-22

Information on the effect of anti-vascular endothelial growth factor therapy in eyes with diabetic macular edema (DME) with vision loss after macular laser photocoagulation is clinically valuable. To evaluate visual and anatomic outcomes in a subgroup of macular laser photocoagulation treatment control (hereafter laser control) eyes with substantial vision loss receiving treatment with intravitreal aflibercept injection. This investigation was a post hoc analysis of a subgroup of laser control eyes in 2 phase 3 trials-VISTA (Study of Intravitreal Aflibercept Injection in Patients With Diabetic Macular Edema) and VIVID (Intravitreal Aflibercept Injection in Vision Impairment Due to DME)-in a multicenter setting. One hundred nine laser control eyes with center-involving DME were included. Treatment with intravitreal aflibercept injection (2 mg) every 8 weeks after 5 monthly doses with sham injections on nontreatment visits starting at week 24 was initiated on meeting prespecified criteria of at least a 10-letter visual acuity loss at 2 consecutive visits or at least a 15-letter visual acuity loss from the best previous measurement at 1 visit and vision not better than at baseline. Visual and anatomic outcomes in a subgroup of laser control eyes receiving treatment with intravitreal aflibercept injection. Through week 100, a total of 63 of 154 eyes (40.9%) in VISTA and 46 of 133 eyes (34.6%) in VIVID initially randomized to laser control received treatment with intravitreal aflibercept injection. The median time from week 24 to the first intravitreal aflibercept injection treatment was 34.0 (VISTA) and 83.5 (VIVID) days. In this subgroup, the mean (SD) visual gain from baseline to week 100 was 2.2 (12.5) (VISTA) and 3.8 (10.1) (VIVID) letters. At the time of intravitreal aflibercept injection initiation, these eyes had a mean (SD) loss of 11.0 (10.1) (VISTA) and 10.0 (6.5) (VIVID) letters from baseline, and they subsequently gained a mean (SD) of 17.4 (9.7) (VISTA) and 13.6 (8.6) (VIVID) letters from the initiation of treatment with intravitreal aflibercept injection through week 100. There was a minimal mean change in central subfield thickness from baseline in these eyes at the time of intravitreal aflibercept injection initiation (an increase of 3.9 μm in VISTA and a decrease of 3.0 μm in VIVID), after which further mean (SD) reductions of 285.6 (202.6) μm (VISTA) and 313.4 (181.9) μm (VIVID) occurred through week 100. Intravitreal aflibercept injection improves visual and anatomic outcomes in eyes experiencing substantial vision loss after macular laser photocoagulation treatment for DME. clinicaltrials.gov Identifiers: NCT01363440 and NCT01331681.

Intravitreous Bevacizumab in the Treatment of Macuar Edema from Branch Retinal Vein Occlusion and Hemisphere Retinal Vein Occlusion (An AOS Thesis)

PubMed Central

Fish, Gary Edd

2008-01-01

Purpose To compare intravitreous bevacizumab to other current treatments of branch retinal vein occlusion (BRVO) and hemisphere retinal vein occlusion (HRVO) with consideration to visual outcome, cost, convenience, and risk of treatment. Methods This is a retrospective chart review from a large referral retina practice. The data comprise 56 patients with BRVO and HRVO treated by intravitreous bevacizumab, with and without intravitreous triamcinolone acetonide. Initial visual acuities at the time of first bevacizumab injection, best acuities through the follow-up time, final acuity at last visit before review, initial macular thickness, and final macular thickness were measured. Changes in vision and thickness were calculated, as were the percentage of eyes improving, stabilizing, and worsening. Results The data were compared to composite data derived from several current treatments of BRVO. The subgroup of 39 eyes that received only bevacizumab without triamcinolone acetonide had the most improvement in vision. The median change in visual acuity was 1.5 lines (P = .012) over a mean follow-up of 8.8 months. Twenty-three eyes (59%) improved visually, with 20 eyes (51%) improving 2 or more lines. These results are similar to those for eyes that received argon grid laser and chorioretinal anastomosis, but are worse than in eyes that received arteriovenous adventitial sheathotomy, macular decompression surgery, and intravitreous triamcinolone acetonide. Conclusions Visual benefit from intravitreous bevacizumab compares well against laser treatments for BRVO and HRVO but not as well opposed to surgical techniques and intravitreous triamcinolone acetonide. Intravitreous bevacizumab injection has a risk, cost, and convenience profile that is favorable. PMID:19277242

Effect of Intravitreal Anti-Vascular Endothelial Growth Factor Therapy on the Risk of Arterial Thromboembolic Events: A Meta-Analysis

PubMed Central

Lu, Guo-Cai; Wei, Rui-Li

2012-01-01

Background Intravitreal anti-vascular endothelial growth factor (VEGF) monoclonal antibodies are used in ocular neovascular diseases. A consensus has emerged that intravenous anti-VEGF can increase the risk of arterial thromboembolic events. However, the role of intravitreal anti-VEGF in arterial thromboembolism is controversial. Therefore, we did a systematic review and meta-analysis to investigate the effects of intravitreal anti-VEGF on the risk of arterial thromboembolic events. Methods Electronic databases were searched to identify relevant randomized clinical trials comparing intravitreal anti-VEGF with controls. Criteria for inclusion in our meta-analysis included a study duration of no less than 12 months, the use of a randomized control group not receiving any intravitreal active agent, and the availability of outcome data for arterial thromboembolic events, myocardial infarction, cerebrovascular accidents, and vascular death. The risk ratios and 95% CIs were calculated using a fixed-effects or random-effects model, depending on the heterogeneity of the included studies. Results A total of 4942 patients with a variety of ocular neovascular diseases from 13 randomized controlled trials were identified and included for analysis. There was no significant difference between intravitreal anti-VEGF and control in the risk of all events, with risk ratios of 0.87 (95% CI, 0.64 to 1.19) for arterial thromboembolic events, 0.96 (95% CI, 0.55–1.68) for cerebrovascular accidents, 0.69 (95% CI 0.40–1.21) for myocardial infarctions, and 0.68 (95% CI, 0.37–1.27) for vascular death. Conclusions The strength evidence suggests that the intravitreal use of anti-VEGF antibodies is not associated with an increased risk of arterial thromboembolic events. PMID:22829940

Intravitreal aflibercept for macular edema secondary to central retinal vein occlusion: 18-month results of the phase 3 GALILEO study.

PubMed

Ogura, Yuichiro; Roider, Johann; Korobelnik, Jean-François; Holz, Frank G; Simader, Christian; Schmidt-Erfurth, Ursula; Vitti, Robert; Berliner, Alyson J; Hiemeyer, Florian; Stemper, Brigitte; Zeitz, Oliver; Sandbrink, Rupert

2014-11-01

To evaluate intravitreal aflibercept for treatment of macular edema secondary to central retinal vein occlusion (CRVO). Randomized, double-masked, phase 3 study. A total of 177 patients with macular edema secondary to CRVO were randomized to receive 2 mg intravitreal aflibercept (n = 106) or sham (n = 71) every 4 weeks for 20 weeks. From weeks 24 to 48, patients were monitored every 4 weeks; the former group received intravitreal aflibercept as needed (PRN), and the sham group received sham. From weeks 52 to 76, patients were monitored every 8 weeks, and both groups received intravitreal aflibercept PRN. The primary endpoint (proportion of patients who gained ≥15 letters) was at week 24. This study reports exploratory outcomes at week 76. The proportion of patients who gained ≥15 letters in the intravitreal aflibercept and sham groups was 60.2% vs 22.1% at week 24 (patients discontinued before week 24 were considered nonresponders; P < .0001), 60.2% vs 32.4% at week 52 (last observation carried forward, P < .001), and 57.3% vs 29.4% at week 76 (last observation carried forward; P < .001). Mean μm change from baseline central retinal thickness was -448.6 vs -169.3 at week 24 (P < .0001), -423.5 vs -219.3 at week 52 (P < .0001), and -389.4 vs -306.4 at week 76 (P = .1122). Over 76 weeks, the most common ocular serious adverse event in the intravitreal aflibercept group was macular edema (3.8%). The visual and anatomic improvements seen after fixed, monthly dosing at week 24 were largely maintained when treatment intervals were extended. Patients with macular edema following CRVO benefited from early treatment with intravitreal aflibercept. Copyright © 2014 Elsevier Inc. All rights reserved.

Nurse-led ranibizumab intravitreal injections in wet age-related macular degeneration: a literature review.

PubMed

Gregg, Emma

2017-04-12

Aim The aim of this literature review was to explore the development of the role of specialist ophthalmic nurses in delivering ranibizumab intravitreal injections to patients with wet age-related macular degeneration (AMD), and to evaluate their contribution to reducing capacity pressures in medical retina services, while maintaining safe and effective standards of care. Method A systematic literature search was undertaken to identify relevant articles published between January 2000 and June 2015. A search of electronic databases was undertaken, and selected relevant journals were searched manually. A free text and subject heading search strategy was conducted, in which the abstracts of publications identified for review were assessed for relevance. Inclusion criteria were: nurses delivering ranibizumab intravitreal treatment; studies performed in the UK and other countries; and patients with AMD, diabetic macular oedema or central retinal vein occlusion receiving nurse-led ranibizumab (Lucentis) intravitreal treatment. Findings Five studies were identified from the literature search, which audited a total of 31,303 injections delivered by nurse practitioners between January 2007 and November 2013. The visual outcomes and the rate of complications from intravitreal injections delivered by trained ophthalmic nurse practitioners were comparable to intravitreal injections delivered by ophthalmologists. Four of the five studies reported increased patient satisfaction, patients consenting to nurse-delivered intravitreal injections, favourable pain experience, and absence of complaints. Conclusion Practice innovation is an example of a quality, innovation, productivity and prevention process. Role expansion, in which specialist ophthalmic nurses deliver intravitreal injections, has been shown to be economical, safe and effective. It enables timely delivery of the service, thereby preventing irreversible blindness for individuals with wet AMD.

Intravitreal Phacoemulsification Using Torsional Handpiece for Retained Lens Fragments.

PubMed

Kumar, Vinod; Takkar, Brijesh

2016-01-01

To evaluate the results of intravitreal phacoemulsification with torsional hand piece in eyes with posteriorly dislocated lens fragments. In this prospective, interventional case series, 15 eyes with retained lens fragments following phacoemulsification were included. All patients underwent standard three-port pars plana vitrectomy and intravitreal phacoemulsification using sleeveless, torsional hand piece (OZiL™, Alcon's Infiniti Vision System). Patients were followed up for a minimum of six months to evaluate the visual outcomes and complications. The preoperative best-corrected visual acuity (BCVA) ranged from light perception to 0.3. No complications such as thermal burns of the scleral wound, retinal damage due to flying lens fragments, or difficult lens aspiration occurred during intravitreal phacoemulsification. Mean post-operative BCVA at the final follow-up was 0.5. Two eyes developed cystoid macular edema, which was managed medically. No retinal detachment was noted. Intravitreal phacoemulsification using torsional hand piece is a safe and effective alternative to conventional longitudinal phacofragmentation.

Retinal degeneration is delayed by tissue factor pathway inhibitor-2 in RCS rats and a sodium-iodate-induced model in rabbits.

PubMed

Obata, R; Yanagi, Y; Tamaki, Y; Hozumi, K; Mutoh, M; Tanaka, Y

2005-04-01

To investigate the in vivo effects of tissue factor pathway inhibitor 2 (TFPI-2), which stimulates proliferation of retinal pigment epithelial cells, but not the proliferation of fibroblast and vascular endothelial cells in vitro, on retinal degeneration using a sodium-iodate (SI)-induced model in rabbits and Royal Collage of Surgeons (RCS) rats. 79 microg of recombinant TFPI-2 (rTFPI-2) or vehicle alone was injected intravitreously to 18 eyes of 12 pigmented rabbits a day after 20 mg/kg of SI was intravenously administered. Retinal function was assessed 4, 7, 14, and 21 days after the injection by analysing amplitudes of the c-wave of a bright flash electroretinogram. Additionally, 10 microg of rTFPI-2 or vehicle alone was injected intravitreously to 11 eyes of RCS rats at both 3 and 4 weeks old, then the retina was examined histologically at 5 weeks old. The rTFPI-2-treated eyes in rabbits showed a significantly less decrease in the relative amplitude of the c-wave than control eyes on days 4 and 7. The thickness of the outer nuclear layer was significantly thicker and the vacuole in the photoreceptor layer was less frequently observed in the rTFPI-2-treated RCS rats than the controls. Intravitreal injection of TFPI-2 rescues SI-induced retinal degeneration in rabbits and naturally occurring retinal degeneration in RCS rats at least partly. These results may suggest that this compound can be utilized in the treatment of retinal degeneration.

Comparative cyto-histological study of needle tip aspirates and entry sites after intravitreal injection using different needle types

PubMed Central

Lytvynchuk, Lyubomyr; Sergienko, Andrij; Savytska, Iryna; Albert, Réka; Glittenberg, Carl; Binder, Susanne; Petrovski, Goran

2017-01-01

A comparison of the cellular content of needle tip aspirates and entry sites after transconjunctival intravitreal injection (IVI) using different needle types was performed. White outbred rats and human cadaver eyes were used for IVI by hypodermic 27 gauge (G) and 30G needles, and spinal anesthesia Pencan 27G needles. Aspiration of vitreous for quantitative morphological and cell cultivation analysis, as well as cyto-histological analysis of aspirates and entry sites were carried out. The most common cells in the aspirates from all needle types were conjunctival epithelial-, ciliary body non-pigmented epithelial- and sclerocyte-like cells and granular proteins. Crystallized vitreous specimens were present in each aspirate. The entry sites of hypodermic needles showed marked trauma in all wall layers of rat and human eyes accompanied by cellular destruction and hemorrhages. Pencan 27G needle caused less tissue trauma with partial reposition of sclerocytes. Transconjunctival IVIs with hypodermic 27G and 30G, and Pencan 27G needles result in trauma of all layers of the eyeball. The possible consequences of cellular content being cut and injected into the eye, as well as the entry site wound shape deserve future consideration and improvements. PMID:28692684

Comparison of treatment regimens for cytomegalovirus retinitis in patients with AIDS in the era of highly active antiretroviral therapy

PubMed Central

Jabs, Douglas A.; Ahuja, Alka; Van Natta, Mark; Dunn, JP; Yeh, Steven

2012-01-01

Purpose To describe the outcomes of different treatment approaches for cytomegalovirus (CMV) retinitis in the era of highly active antiretroviral therapy (HAART). Design Prospective cohort study, the Longitudinal Study of the Ocular Complications of AIDS. Participants 250 patients with CMV retinitis and CD4+ T cells <100 cells/µL (n=221) at enrollment or incident retinitis (n=29) during cohort follow-up. Methods The effects of systemic therapy (vs. intraocular therapy only) on systemic outcomes and the effect of intraocular therapies (ganciclovir implants, intravitreal injections) on ocular outcomes were evaluated. Main Outcome Measures Mortality, CMV dissemination, retinitis progression, treatment side effects. Results Regimens containing systemic anti-CMV therapy were associated with a 50% reduction in mortality (adjusted hazard ratio [HR]=0.5; 95% confidence interval [CI] = 0.3, 0.7; P=0.006), 90% reduction in new visceral CMV disease (adjusted HR=0.1; 95% CI = 0.04, 0.4;P=0.004), and among those with unilateral CMV retinitis at presentation, an 80% reduction in second eye disease (adjusted HR=0.2; 95% CI= 0.1, 0.5; P=0.0005) when compared to those using only intraocular therapy (implants or injections). Compared to systemic treatment only, regimens containing intravitreal injections had greater rates of retinitis progression (adjusted HR=3.4, P=0.004) and greater visual field loss (for loss of ½ of the normal field, adjusted HR=5.5, P<0.01). Intravitreal implants were not significantly better than systemic therapy (adjusted HR for progression =0.5, P=0.26, and for loss ½ visual field =0.5, P=0.45), but the sample size was small. Hematologic and renal side effect rates were similar between those groups with and without systemic anti-CMV therapy. The rate of endophthalmitis among those treated with intravitreal injections was 0.017/EY (95% CI =0.006, 0.05) and among those treated with an implant 0.01/EY (95% CI =0.002, 0.04). Conclusions In the HAART era, systemic anti-CMV therapy, while there is immune compromise, appears to provide benefits in terms of longer survival and decreased CMV dissemination. PMID:23419804

Non-physician delivered intravitreal injection service is feasible and safe - a systematic review.

PubMed

Rasul, Asrin; Subhi, Yousif; Sørensen, Torben Lykke; Munch, Inger Christine

2016-05-01

Non-physicians such as nurses are trained to give injections into the vitreous body of the eye to meet the increasing demand for intravitreal therapy with vascular endothelial growth factor inhibitors against common eye diseases, e.g. age-related macular degeneration and diabetic retinopathy. We systematically reviewed the existing literature to provide an overview of the experiences in this transformational process. We searched for literature on 22 September 2015 using PubMed, Embase, the Cochrane Library, CINAHL and the Web of Science. Eligible studies had to address any outcome based on non-physician delivered intravitreal therapy regardless of the study design. Being non-physician was defined as the injecting personnel not being a physician, but no further restrictions were made. Five studies were included with a total of 31,303 injections having been performed by 16 nurses. The studies found that having nurses perform the intravitreal injections produced to a short-term capacity improvement and liberated physicians for other clinical work. Training was provided through courses and direct supervision. The rates of endophthalmitis were 0-0.40‰, which is comparable to reported rates when the intravitreal therapy is given by physicians. Non-physician delivered intravitreal therapy seems feasible and safe.

Peripheral retinal non-perfusion and treatment response in branch retinal vein occlusion.

PubMed

Abri Aghdam, Kaveh; Reznicek, Lukas; Soltan Sanjari, Mostafa; Framme, Carsten; Bajor, Anna; Klingenstein, Annemarie; Kernt, Marcus; Seidensticker, Florian

2016-01-01

To evaluate the association between the size of peripheral retinal non-perfusion and the number of intravitreal ranibizumab injections in patients with treatment-naive branch retinal vein occlusion (BRVO) and macular edema. A total of 53 patients with treatment-naive BRVO and macular edema were included. Each patient underwent a full ophthalmologic examination including optical coherence tomography (OCT) imaging and ultra wide-field fluorescein angiography (UWFA). Monthly intravitreal ranibizumab injections were applied according to the recommendations of the German Ophthalmological Society. Two independent, masked graders quantified the areas of peripheral retinal non-perfusion. Intravitreal injections improved best-corrected visual acuity (BCVA) significantly from 22.23±16.33 Early Treatment of Diabetic Retinopathy Study (ETDRS) letters to 36.23±15.19 letters (P<0.001), and mean central subfield thickness significantly reduced from 387±115 µm to 321±115 µm (P=0.01). Mean number of intravitreal ranibizumab injections was 3.61±1.56. The size of retinal non-perfusion correlated significantly with the number of intravitreal ranibizumab injections (R=0.724, P<0.001). Peripheral retinal non-perfusion in patients with BRVO associates significantly with intravitreal ranibizumab injections in patients with BRVO and macular edema.

Repeated intraocular crystallization of ganciclovir in one eye after bilateral intravitreal injections: a case report.

PubMed

Iu, Lawrence P L; Fan, Michelle C Y; Lam, Wai-Ching; Wong, Ian Y H

2018-02-09

Cytomegalovirus (CMV) retinitis is an opportunistic infection that primarily affects immunocompromised individuals. Intravitreal ganciclovir injection monotherapy or in combination with systemic anti-CMV therapy are effective treatments for CMV retinitis. Crystallization of ganciclovir after intravitreal injection is extremely rare. Only two cases had been reported in literature. Crystallization in only one eye after bilateral injections had not been reported before. We hereby report a case of intraocular ganciclovir crystallization in one eye after bilateral intravitreal injections, and repeated crystallization in the same eye after repeated injections. A 79-year-old patient had bilateral cytomegalovirus retinitis and received bilateral intravitreal ganciclovir injections of 2.5 mg in 0.05 ml sterile water. Fundus examination after injection showed formation of needle-shaped, golden-yellow crystals in the vitreous of right eye but not in left eye. The crystals dissolved spontaneously. Repeated bilateral intravitreal ganciclovir injections 4 days later resulted in repeated crystallization of ganciclovir in right eye but not in left eye. The crystals dissolved spontaneously and completely after 5 minutes. Visual acuity remained unchanged and intraocular pressure was normal. Intraocular ganciclovir crystallization could occur after intravitreal injections. It is important to perform fundus examination after injection. The crystals may dissolve rapidly and vitrectomy may not be necessary. Our case suggested intraocular ganciclovir crystallization is an idiosyncratic phenomenon, subjects to distinctive intraocular environment which could be different between two eyes of the same patient. The susceptible intraocular environment could be persistent leading to repeated crystallization.

Silencing of galectin-1 inhibits retinal neovascularization and ameliorates retinal hypoxia in a murine model of oxygen-induced ischemic retinopathy.

PubMed

Yang, Ning; Zhang, Wenxi; He, Tao; Xing, Yiqiao

2017-06-01

Aberrant neovascularization is a consequence of inappropriate angiogenic signaling and contributes to several diseases. Although many regulators of pathogenic angiogenesis have been identified, the understanding of this process remains incomplete. Galectin-1 (Gal-1), as a homodimeric protein with a single carbohydrate-recognition domain, is implicated in several pathologic processes, including angiogenesis; however, its involvement in retinal neovascularization (RNV) remains unknown. Here, we investigated the anti-angiogenic effect of silencing Gal-1 through intravitreal injection in a mouse model of oxygen-induced retinopathy (OIR). Our results revealed that Gal-1 was overexpressed and closely related to retinal neo-vessels in OIR retinas. After silencing Gal-1 via intravitreal injection of adenoviral-Gal-1-RNA interference (Ad-Gal-1-RNAi), RNV and retinal hypoxia were significantly attenuated, indicating the anti-angiogenic effect of Gal-1 inhibition. Western blot analysis and real-time polymerase chain reaction indicated that the expression of both neuropilin-1 (Nrp-1) and B cell lymphoma-2 (Bcl-2) decreased after intravitreal injection of Ad-Gal-1-RNAi, implying the possible involvement of Nrp-1 and Bcl-2 in Gal-1-related angiogenic processes. Additionally, whole-mount fluorescence and hematoxylin and eosin staining showed that intravitreal injection of Ad-Gal-1-RNAi did not significantly disrupt the retinal vasculature and neuronal structure of room air mice. Moreover, Ad-Gal-1-RNAi transfer promoted retinal vascular sprouting and increased retinal vascular perfusion, likely through decreased phosphorylation of myosin phosphatase target protein-1. Collectively, our results demonstrated that Gal-1 functions as an important regulator in RNV and offers a promising strategy for the treatment of RNV diseases, such as proliferative diabetic retinopathy and retinopathy of prematurity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Intravitreal injection of rapamycin-loaded polymeric micelles for inhibition of ocular inflammation in rat model.

PubMed

Wu, Wei; He, Zhifen; Zhang, Zhaoliang; Yu, Xinxin; Song, Zongming; Li, Xingyi

2016-11-20

The therapeutic efficacy of rapamycin conjugated monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles (rapamycin micelles) was evaluated in a rat experimental autoimmune uveitis (EAU) model. Rapamycin micelles exhibited spherical morphology and had a mean particle size of 40nm and a zeta-potential of -0.89mv. The water solubility of rapamycin improved by more than 1000-fold in a micellar formulation. Intravitreal injection of MPEG-PCL micelles did not result in vitreous hemorrhage or retinal detachment. Fluorescence microscopy demonstrated that labeled micelles localized to the retinal pigment epithelium for at least 14 days following injection and the drug concentration of rapamycin micelles in the retinal tissue was significantly higher than unconjugated rapamycin over this period. At the optimal concentration of rapamycin micelles (9μg/eye), clinical signs of EAU were abolished via the downregulation of the Th1 and Th17 response. There were no significant difference in T cell proliferation and delayed-type hypersensitivity between the treatment and control groups, suggesting that the therapeutic effect of rapamycin manifested locally in the eye and not systemically. These results indicate that intravitreal injection of rapamycin micelles is a promising therapy for controlling sterile intraocular inflammation. Copyright © 2016 Elsevier B.V. All rights reserved.

The relation between bevacizumab injection and the formation of subretinal fibrosis in diabetic patients with panretinal photocoagulation.

PubMed

Batman, Cosar; Ozdamar, Yasemin

2010-01-01

To report the development of subretinal fibrosis after the injection of intravitreal bevacizumab in eyes with proliferative diabetic retinopathy (PDR) refractory to panretinal laser photocoagulation (PRP). Twenty-one eyes of 15 patients treated with PRP and intravitreal injection of bevacizumab were included in this study. The clinical outcomes of 21 eyes having subretinal fibrosis after intravitreal bevacizumab injection were reviewed. There were 9 men and 6 women with a mean age of 51.3 +/- 8.9 years. All eyes had PDR refractory to panretinal photocoagulation and were treated with at least one intravitreal injection of 1.25 mg of bevacizumab (mean number of injections: 1.8). Before injection, there was subretinal fibrosis in 5 eyes and vitreoretinal traction in 19 eyes. After a mean follow-up period of 7 months, the development or progression of subretinal fibrosis was detected in all eyes. Intravitreal injection of bevacizumab may cause formation or progression of subretinal fibrosis in patients with PDR refractory to PRP. Copyright 2010, SLACK Incorporated.

Intravitreal Phacoemulsification Using Torsional Handpiece for Retained Lens Fragments

PubMed Central

Kumar, Vinod; Takkar, Brijesh

2016-01-01

Purpose: To evaluate the results of intravitreal phacoemulsification with torsional hand piece in eyes with posteriorly dislocated lens fragments. Methods: In this prospective, interventional case series, 15 eyes with retained lens fragments following phacoemulsification were included. All patients underwent standard three-port pars plana vitrectomy and intravitreal phacoemulsification using sleeveless, torsional hand piece (OZiL™, Alcon's Infiniti Vision System). Patients were followed up for a minimum of six months to evaluate the visual outcomes and complications. Results: The preoperative best-corrected visual acuity (BCVA) ranged from light perception to 0.3. No complications such as thermal burns of the scleral wound, retinal damage due to flying lens fragments, or difficult lens aspiration occurred during intravitreal phacoemulsification. Mean post-operative BCVA at the final follow-up was 0.5. Two eyes developed cystoid macular edema, which was managed medically. No retinal detachment was noted. Conclusion: Intravitreal phacoemulsification using torsional hand piece is a safe and effective alternative to conventional longitudinal phacofragmentation. PMID:27621783

Uneventful Anterior Migration of Intravitreal Ozurdex Implant in a Patient with Iris-Sutured Intraocular Lens and Descemet Stripping Automated Endothelial Keratoplasty.

PubMed

Zafar, Andleeb; Aslanides, Ioannis M; Selimis, Vasileios; Tsoulnaras, Konstantinos I; Tabibian, David; Kymionis, George D

2018-01-01

We report here the case of a patient with anterior segment migration of intravitreal dexamethasone implant as well as its management and outcome. The patient had the following sequence of events: complicated cataract surgery, iris-sutured intraocular lens implant, followed by cystoid macular edema treated with intravitreal Avastin, retinal vein occlusion treated with intravitreal dexamethasone implant, corneal decompensation treated with Descemet stripping automated endothelial keratoplasty (DSAEK), and finally recurrence of macular edema treated with repeated intravitreal dexamethasone implant. Dexamethasone implant had completely dissolved from the eye 12 weeks after insertion without any complication. A conservative approach with regular monitoring in the situation of a quiet anterior segment without any corneal decompensation can provide enough time for the implant to dissolve without causing any complication to the involved eye, avoiding any additional surgical intervention, as presented in this case report. Despite the fact that the implant was left for natural dissolution, there were no adverse effects related to the graft or the eye.

Toxic corneal epitheliopathy after intravitreal methotrexate and its treatment with oral folic acid.

PubMed

Gorovoy, Ian; Prechanond, Tidarat; Abia, Maravillas; Afshar, Armin R; Stewart, Jay M

2013-08-01

To determine whether oral folic acid can ameliorate an iatrogenic, visually significant corneal epitheliopathy, which commonly occurs with intravitreal injections of methotrexate for the treatment of intraocular lymphoma. We report 2 cases of visually significant corneal epitheliopathy occurring after intravitreal injections of methotrexate for intraocular lymphoma. The first patient did not receive any treatment for the corneal disease, and the second patient with bilateral intraocular lymphoma received 1 mg of oral folic acid daily, a commonly used dosage for patients on systemic methotrexate. In the first patient without treatment, there was a complete regression of the corneal epithelial disease only when the frequency of intravitreal methotrexate was reduced from weekly to monthly as per a commonly used dosage regimen for methotrexate. In the second patient, the corneal disease improved 80% within 1 week of initiating oral folic acid for her eye already experiencing severe epitheliopathy during her weekly dosing regimen of methotrexate and also had significantly decreased epithelial disease in her second eye that started weekly intravitreal methotrexate several weeks after beginning oral folic acid. Currently, oral folic acid supplements are recommended for patients using systemic methotrexate to minimize drug toxicity. We suggest a similar use in patients undergoing intravitreal methotrexate injections to decrease toxic effects on the corneal epithelium.

Peripheral retinal non-perfusion and treatment response in branch retinal vein occlusion

PubMed Central

Abri Aghdam, Kaveh; Reznicek, Lukas; Soltan Sanjari, Mostafa; Framme, Carsten; Bajor, Anna; Klingenstein, Annemarie; Kernt, Marcus; Seidensticker, Florian

2016-01-01

AIM To evaluate the association between the size of peripheral retinal non-perfusion and the number of intravitreal ranibizumab injections in patients with treatment-naive branch retinal vein occlusion (BRVO) and macular edema. METHODS A total of 53 patients with treatment-naive BRVO and macular edema were included. Each patient underwent a full ophthalmologic examination including optical coherence tomography (OCT) imaging and ultra wide-field fluorescein angiography (UWFA). Monthly intravitreal ranibizumab injections were applied according to the recommendations of the German Ophthalmological Society. Two independent, masked graders quantified the areas of peripheral retinal non-perfusion. RESULTS Intravitreal injections improved best-corrected visual acuity (BCVA) significantly from 22.23±16.33 Early Treatment of Diabetic Retinopathy Study (ETDRS) letters to 36.23±15.19 letters (P<0.001), and mean central subfield thickness significantly reduced from 387±115 µm to 321±115 µm (P=0.01). Mean number of intravitreal ranibizumab injections was 3.61±1.56. The size of retinal non-perfusion correlated significantly with the number of intravitreal ranibizumab injections (R=0.724, P<0.001). CONCLUSION Peripheral retinal non-perfusion in patients with BRVO associates significantly with intravitreal ranibizumab injections in patients with BRVO and macular edema. PMID:27366688

Effects of Intravitreal Ranibizumab in the Treatment of Retinopathy of Prematurity in Chinese Infants.

PubMed

Yi, Zuohuizi; Su, Yu; Zhou, Yunyun; Zheng, Hongmei; Ye, Meihong; Xu, Yonghong; Chen, Changzheng

2016-08-01

To evaluate the efficacy associated with intravitreal ranibizumab in the treatment of retinopathy of prematurity (ROP). A retrospective case series study. Infants diagnosed with Type 1 ROP, or aggressive posterior ROP (AP-ROP) were enrolled in the study. All infants in the study received intravitreal ranibizumab (0.25 mg/0.025 ml) as the initial treatment. Follow-up examinations were performed the day after treatment, then weekly for 1 month, bi-monthly for two additional months, then monthly until vascularization of zone III occurred. Additional treatments were initiated in cases of disease recurrence. Thirty-three premature infants (a total of 66 eyes) receiving intravitreal ranibizumab were included. The mean birth weight was 1291 ± 211 g (range: 650-1650 g) and the mean gestational age was 29.8 ± 1.6 weeks (range: 27.0-33.6 weeks). The mean gestational age at the time of the first injection was 35.8 ± 1.6 weeks (range: 32.7-38.4 weeks). The mean follow-up time was 12.9 ± 4.9 months (range: 6-22 months). Single injections were administered to 58 eyes (87.9%), whereas eight eyes (12.1%) received additional treatments. Recurrence was observed in eight eyes (12.1%), with a mean time to recurrence of 6.9 ± 1.8 weeks (range: 4-8 weeks). Intravitreal ranibizumab is effective for the treatment of retinopathy of prematurity, although a small amount of patients recurred. Compared with intravitreal bevacizumab, a higher incidence and shorter time to recurrence were observed after intravitreal ranibizumab treatment, thus longer and more frequent follow-ups are needed.

Cytomegalovirus retinitis after intravitreal bevacizumab injection in an immunocompetent patient.

PubMed

Bae, So Hyun; Kim, Tae Wan; Chung, Hum; Heo, Jang Won

2013-02-01

We report a case of cytomegalovirus (CMV) retinitis after intravitreal bevacizumab injection. A 61-year-old woman with diabetic macular edema developed dense vitritis and necrotizing retinitis 3 weeks after intravitreal bevacizumab injection. A diagnostic vitrectomy was performed. The undiluted vitreous sample acquired by vitrectomy was analyzed by polymerase chain reaction and culture. Polymerase chain reaction of the vitreous was positive for CMV DNA. Other laboratory results did not show evidence of other infectious retinitis and systemic immune dysfunction. Human immunodeficiency virus antibodies were also negative. After systemic administration of ganciclovir, retinitis has resolved and there has been no recurrence of retinitis during the follow-up period of 12 months. Ophthalmologists should be aware of potential risk for CMV retinitis after intravitreal bevacizumab injection.

Intravitreal injection of forskolin, homotaurine, and L-carnosine affords neuroprotection to retinal ganglion cells following retinal ischemic injury.

PubMed

Russo, Rossella; Adornetto, Annagrazia; Cavaliere, Federica; Varano, Giuseppe Pasquale; Rusciano, Dario; Morrone, Luigi Antonio; Corasaniti, Maria Tiziana; Bagetta, Giacinto; Nucci, Carlo

2015-01-01

Retinal ganglion cell (RGC) death is the final event leading to visual impairment in glaucoma; therefore, identification of neuroprotective strategies able to slow down or prevent the process is one of the main challenges for glaucoma research. The purpose of this study was to evaluate the neuroprotective potential of RGC death induced by the in vivo transient increase in intraocular pressure (IOP) of a combined treatment with forskolin, homotaurine, and L-carnosine. Forskolin (7beta-acetoxy-8, 13-epoxy-1a, 6β, 9a-trihydroxy-labd-14-en-11-one) is an activator of adenylate cyclase that decreases IOP by reducing aqueous humor production and functions as a neuroprotector due to its neurotrophin-stimulating activity. Homotaurine is a natural aminosulfonate compound endowed with neuromodulatory effects, while the dipeptide L-carnosine is known for its antioxidant properties. Retinal ischemia was induced in the right eye of adult male Wistar rats by acutely increasing the IOP. Forskolin, homotaurine, and L-carnosine were intravitreally injected and RGC survival evaluated following retrograde labeling with FluoroGold. Total and phosphorylated Akt and glycogen synthase kinase-3β (GSK-3β) protein levels, as well as calpain activity, were analyzed with western blot. Protein kinase A (PKA) was inhibited by intravitreal injection of H89. A synergic neuroprotective effect on RGC survival was observed following the combined treatment with forskolin, homotaurine, and L-carnosine compared to forskolin alone. The observed neuroprotection was associated with reduced calpain activity, upregulation of phosphoinositide 3-kinase (PI3K)/Akt pathway, and inhibition of GSK-3β but was independent from PKA activation and distinct from the hypotensive effects of forskolin. A multidrug/multitarget approach, by interfering with several pathways involved in RGC degeneration, may be promising to achieve glaucoma neuroprotection.

Retinoblastoma Vitreous Seed Clouds (Class 3): A Comparison of Treatment with Ophthalmic Artery Chemosurgery with or without Intravitreous and Periocular Chemotherapy.

PubMed

Francis, Jasmine H; Iyer, Saipriya; Gobin, Y Pierre; Brodie, Scott E; Abramson, David H

2017-10-01

To compare the efficacy and toxicity of treating class 3 retinoblastoma vitreous seeds with ophthalmic artery chemosurgery (OAC) alone versus OAC with intravitreous chemotherapy. Retrospective cohort study. Forty eyes containing clouds (class 3 vitreous seeds) of 40 retinoblastoma patients (19 treated with OAC alone and 21 treated with OAC plus intravitreous and periocular chemotherapy). Ocular survival, disease-free survival and time to regression of seeds were estimated with Kaplan-Meier estimates. Ocular toxicity was evaluated by clinical findings and electroretinography: 30-Hz flicker responses were compared at baseline and last follow-up visit. Continuous variables were compared with Student t test, and categorical variables were compared with the Fisher exact test. Ocular survival, disease-free survival, and time to regression of seeds. There were no disease- or treatment-related deaths and no patient demonstrated externalization of tumor or metastatic disease. There was no significant difference in the age, laterality, disease, or disease status (treatment naïve vs. previously treated) between the 2 groups. The time to regression of seeds was significantly shorter for eyes treated with OAC plus intravitreous chemotherapy (5.7 months) compared with eyes treated with OAC alone (14.6 months; P < 0.001). The 18-month Kaplan-Meier estimates of disease-free survival were significantly worse for the OAC alone group: 67.1% (95% confidence interval, 40.9%-83.6%) versus 94.1% (95% confidence interval, 65%-99.1%) for the OAC plus intravitreous chemotherapy group (P = 0.05). The 36-month Kaplan-Meier estimates of ocular survival were 83.3% (95% confidence interval, 56.7%-94.3%) for the OAC alone group and 100% for the OAC plus intravitreous chemotherapy group (P = 0.16). The mean change in electroretinography responses was not significantly different between groups, decreasing by 11 μV for the OAC alone group and 22 μV for the OAC plus intravitreous chemotherapy group (P = 0.4). Treating vitreous seed clouds with OAC and intravitreous and periocular chemotherapy, compared with OAC alone, resulted in a shorter time to regression and was associated with fewer recurrences requiring additional treatment and fewer enucleations. The toxicity to the retina does not seem to be significantly worse in the OAC plus intravitreous chemotherapy group. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Intravitreal aflibercept injection for macular edema secondary to central retinal vein occlusion: 1-year results from the phase 3 COPERNICUS study.

PubMed

Brown, David M; Heier, Jeffrey S; Clark, W Lloyd; Boyer, David S; Vitti, Robert; Berliner, Alyson J; Zeitz, Oliver; Sandbrink, Rupert; Zhu, Xiaoping; Haller, Julia A

2013-03-01

To evaluate intravitreal aflibercept injections (IAI; also called VEGF Trap-Eye) for patients with macular edema secondary to central retinal vein occlusion (CRVO). Randomized controlled trial. This multicenter study randomized 189 patients (1 eye/patient) with macular edema secondary to CRVO to receive 6 monthly injections of either 2 mg intravitreal aflibercept (IAI 2Q4) (n = 115) or sham (n = 74). From week 24 to week 52, all patients received 2 mg intravitreal aflibercept as needed (IAI 2Q4 + PRN and sham + IAI PRN) according to retreatment criteria. The primary endpoint was the proportion of patients who gained ≥15 ETDRS letters from baseline at week 24. Additional endpoints included visual, anatomic, and quality-of-life NEI VFQ-25 outcomes at weeks 24 and 52. At week 24, 56.1% of IAI 2Q4 patients gained ≥15 letters from baseline compared with 12.3% of sham patients (P < .001). At week 52, 55.3% of IAI 2Q4 + PRN patients gained ≥15 letters compared with 30.1% of sham + IAI PRN patients (P < .001). At week 52, IAI 2Q4 + PRN patients gained a mean of 16.2 letters of vision vs 3.8 letters for sham + IAI PRN (P < .001). The most common adverse events for both groups were conjunctival hemorrhage, eye pain, reduced visual acuity, and increased intraocular pressure. Monthly injections of 2 mg intravitreal aflibercept for patients with macular edema secondary to CRVO resulted in a statistically significant improvement in visual acuity at week 24, which was largely maintained through week 52 with intravitreal aflibercept PRN dosing. Intravitreal aflibercept injection was generally well tolerated. Copyright © 2013 Elsevier Inc. All rights reserved.

A pilot study on the combination treatment of reduced-fluence photodynamic therapy, intravitreal ranibizumab, intravitreal dexamethasone and oral minocycline for neovascular age-related macular degeneration.

PubMed

Sivaprasad, S; Patra, S; DaCosta, J; Adewoyin, T; Shona, O; Pearce, E; Chong, N V

2011-01-01

To assess the safety and efficacy of the combined treatment of reduced-fluence verteporfin photodynamic therapy (PDT), intravitreal ranibizumab, intravitreal dexamethasone and oral minocycline for choroidal neovascularisa- tion (CNV) secondary to age-related macular degeneration (AMD). Nineteen patients with subfoveal CNV secondary to AMD were recruited into the trial. All study eyes (n = 19) received a single cycle of reduced-fluence (25 mJ/cm(2)) PDT with verteporfin followed by an intravitreal injection of ranibizumab 0.3 mg/0.05 ml and dexamethasone 200 μg at baseline. Oral minocycline 100 mg daily was started the following day and continued for 3 months. Patients were followed up monthly for 12 months. Repeat intravitreal ranibizumab was given if best-corrected visual acuity (BCVA) deteriorated by >5 letters on the Early Treatment Diabetic Retinopathy Study (ETDRS) chart or central retinal thickness (CRT) on ocular coherence tomography increased >100 μm. Eighteen patients completed the 12-month study. Stable vision (loss of ≤15 ETDRS letters) was maintained in 89% eyes (16/18). The mean change in BCVA was -5.0 ± 10.5 ETDRS letters. The mean number of ranibizumab injections was 3.4 (range 2-6). The mean reduction in the CRT was 66.3 μm (±75). This open-label clinical trial has demonstrated the safety in terms of adverse effects and maintenance of stable vision of combination treatment with verteporfin, ranibizumab, dexamethasone and minocycline in exudative AMD. However, the outcomes with reduced-fluence PDT combination therapy does not differ significantly with outcomes of clinical trials on combination treatment with standard dose PDT and intravitreal ranibizumab in neovascular AMD. Copyright © 2011 S. Karger AG, Basel.

EFFICACY AND SAFETY OF INTRAVITREAL AFLIBERCEPT AND RANIBIZUMAB IN ASIAN PATIENTS WITH NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: Subgroup Analyses From the View Trials.

PubMed

Wong, Tien Yin; Cheung, Chui Ming Gemmy; Lai, Timothy Y Y; Chen, Shih-Jen; Lee, Won Ki; Yoon, Young Hee; Iida, Tomohiro; Tueckmantel, Claudia; Sowade, Olaf; Ogura, Yuichiro

2017-12-26

To assess the treatment effect of intravitreal aflibercept and ranibizumab in Asian patients with neovascular age-related macular degeneration. We evaluated data from VIEW 1 and VIEW 2, comparing functional and morphologic outcomes at Week 96 between intravitreal aflibercept 2 mg monthly (2q4) or 2 mg bimonthly after 3 initial monthly doses (2q8) versus ranibizumab 0.5 mg monthly among Asian patients (n = 269) and between Asian and white patients (n = 2044). In Asian patients, there were no significant differences between intravitreal aflibercept 2q4 and 2q8 compared with ranibizumab in mean gain in best-corrected visual acuity (10.23 and 8.35 vs. 8.51 letters). Reduction in central retinal thickness was greater for intravitreal aflibercept 2q4 (150.43 μm, P = 0.0075) and 2q8 (148.15 μm, P = 0.0126) than ranibizumab (119.46 μm). The proportion of dry retinas was greater for intravitreal aflibercept 2q4 (65.7%, P < 0.01) than ranibizumab (41.7%). There were no differences in outcomes between Asian and white patients. Serious treatment-emergent ocular adverse events occurred in <8% of treated eyes, evenly distributed across subgroups. In Asian patients with neovascular age-related macular degeneration, functional and morphologic outcomes were largely similar between intravitreal aflibercept and ranibizumab groups, and to results seen in white patients.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

High-dose methotrexate following intravitreal methotrexate administration in preventing central nervous system involvement of primary intraocular lymphoma.

PubMed

Akiyama, Hiroki; Takase, Hiroshi; Kubo, Fumito; Miki, Tohru; Yamamoto, Masahide; Tomita, Makoto; Mochizuki, Manabu; Miura, Osamu; Arai, Ayako

2016-10-01

In order to prevent central nervous system (CNS) involvement and improve the prognosis of primary intraocular lymphoma (PIOL), we prospectively evaluated the efficacy of combined therapy using intravitreal methotrexate (MTX) and systemic high-dose MTX on treatment-naïve PIOL. Patients with newly diagnosed PIOL whose lymphoma was limited to the eyes were enrolled. The patients were treated with weekly intravitreal MTX until the ocular lesions were resolved, followed by five cycles of systemic high-dose MTX (3.5 g/m 2 ) every other week. Ten patients were enrolled in this study and completed the treatment. All patients achieved complete response for their ocular lesions with rapid decrease of intravitreal interleukin-10 concentration. Adverse events of intravitreal and systemic high-dose MTX were mild and tolerable. With a median follow-up of 29.5 months, four patients (40%) experienced the CNS disease development and the mean CNS lymphoma-free survival (CLFS) time was 51.1 months. Two-year CLFS, which was the primary end-point of the study, was 58.3% (95% confidence interval, 23.0-82.1%). In contrast, eight patients were treated with intravitreal MTX alone in our institute, and their 2-year CLFS was 37.5% (95% confidence interval, 8.7-67.4%). In conclusion, systemic high-dose MTX following intravitreal MTX is feasible and might be effective in preventing CNS involvement of PIOL. Further arrangements are worth considering in order to improve the effects. This study was registered with UMIN Clinical Trials Registry (UMIN000003921). © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Intravitreal Adalimumab in Active Noninfectious Uveitis: A Pilot Study.

PubMed

Hamam, Rola N; Barikian, Anita W; Antonios, Rafic S; Abdulaal, Marwan R; Alameddine, Ramzi M; El Mollayess, Georges; Mansour, Ahmad M

2016-06-01

To evaluate the short-term efficacy of intravitreal adalimumab (IVA) for the treatment of eyes with active noninfectious uveitis. Consecutive eyes with active noninfectious uveitis were injected with IVA at 0, 2, then every 4 weeks for total of 26 weeks. Six out of 7 patients (12 of 13 eyes) completed 26 weeks of treatment. One patient (1 eye) failed treatment. Seven out of 12 eyes had improvement of ≥2 ETDRS lines. Three out of three eyes had resolution of anterior chamber cells. And 9 of 10 eyes with vitreous haze had zero haze at 26 weeks. Five out of 8 eyes with macular edema had complete resolution. Median fluorescein angiography score improved from 14 to 4 on last follow-up. IVA was effective in controlling the inflammation, decreasing the macular edema, and improving the best corrected visual acuity in the majority of eyes in this series.

A protocol for the retina surgeon's safe initial intravitreal injections.

PubMed

Frenkel, Ronald E P; Haji, Shamim A; La, Melvin; Frenkel, Max P C; Reyes, Angela

2010-11-10

To determine the safety of a surgeon's initial consecutive intravitreal injections using a specific protocol and to review the complications that may be attributed to the injection procedure. A retrospective chart review. Fifty-nine patients (30 females, 29 males) received intravitreal injections of pegaptanib, bevacizumab, or ranibizumab as part of their treatment for neovascular age-related macular degeneration. The average patient age was 80 years. Twenty-two patients were diagnosed with or suspected of having glaucoma. Each patient received an average of 5.8 injections. The charts of 59 patients who received a total of 345 intravitreal injections (104 pegaptanib, 74 bevacizumab, 167 ranibizumab) were reviewed. All injections were performed in an office-based setting. Povidone-iodine, topical antibiotics, and eye speculum were used as part of the pre injection procedure. Vision and intraocular pressure were evaluated immediately following each injection. Incidence of post injection complications, including but not limited to endophthalmitis, retinal detachment, traumatic cataract, and vitreous hemorrhage. There were no cases of endophthalmitis, toxic reactions, traumatic cataracts, retinal detachment, or vitreous hemorrhage. There was one case each of lid swelling, transient floaters, retinal pigment epithelial tear, corneal edema, and corneal abrasion. There were five cases of transient no light perception following pegaptanib injections. The incidence of serious complications was very low for the intravitreal injections given. A surgeon's initial intravitreal injections may be performed with a very high degree of safety using this protocol.

[Incidence of endophthalmitis after intravitreal injection: is antibioprophylaxis mandatory?].

PubMed

Ramel, J-C; Bron, A-M; Isaico, R; Meillon, C; Binquet, C; Creuzot-Garcher, C

2014-04-01

Endophthalmitis is the most dreaded complication after intravitreal injection. With the rise of antiangiogenics their rate is getting higher each year. The use of antibioprophylaxis is controversial. We tried to evaluate the impact of antibioprophylaxis on intravitreal injection endophthalmitis incidence. All patients who received intravitreal injections between January 2007 and October 2012 were included in this retrospective study. Until June 2012 all patients had antibiotics the days following the injection. From July 2012 the antibiotic was replaced by an antiseptic immediately after the injection. An overall number of 11,450 injections were performed. The overall rate of endophthalmitis was 6/11,450 (0.052%). The incidence of endophthalmitis in the group with antibiotics was 3/10,144 injections (0.03%), 2 were culture proven (0.02%). The incidence in the group without antibiotics was 3/1306 (0.23%). The difference was significant (P=0.024). The incidence of endophthalmitis post-intravitreal injections seems to be lower when using antibiotics. However, a prospective study is mandatory to draw more robust conclusions. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Uneventful Anterior Migration of Intravitreal Ozurdex Implant in a Patient with Iris-Sutured Intraocular Lens and Descemet Stripping Automated Endothelial Keratoplasty

PubMed Central

Zafar, Andleeb; Aslanides, Ioannis M.; Selimis, Vasileios; Tsoulnaras, Konstantinos I.; Tabibian, David; Kymionis, George D.

2018-01-01

Purpose We report here the case of a patient with anterior segment migration of intravitreal dexamethasone implant as well as its management and outcome. Methods The patient had the following sequence of events: complicated cataract surgery, iris-sutured intraocular lens implant, followed by cystoid macular edema treated with intravitreal Avastin, retinal vein occlusion treated with intravitreal dexamethasone implant, corneal decompensation treated with Descemet stripping automated endothelial keratoplasty (DSAEK), and finally recurrence of macular edema treated with repeated intravitreal dexamethasone implant. Results Dexamethasone implant had completely dissolved from the eye 12 weeks after insertion without any complication. Conclusion A conservative approach with regular monitoring in the situation of a quiet anterior segment without any corneal decompensation can provide enough time for the implant to dissolve without causing any complication to the involved eye, avoiding any additional surgical intervention, as presented in this case report. Despite the fact that the implant was left for natural dissolution, there were no adverse effects related to the graft or the eye. PMID:29643797

Chronic cystoid macular oedema treated with intravitreal dobesilate

PubMed Central

Cuevas, Pedro; Outeiriño, Luis A; Angulo, Javier; Giménez-Gallego, Guillermo

2012-01-01

Dobesilate is an anti-inflammatory and antipermeability agent. Intravitreal administration of this compound is a therapeutically beneficial agent in the treatment of chronic cystoid macular oedema. PMID:22778475

Intravitreal flomoxef sodium in rabbits.

PubMed

Mochizuki, K; Torisaki, M; Yamashita, Y; Komatsu, M; Tanahashi, T

1993-01-01

We studied the intraocular concentration of flomoxef sodium in nonvitrectomized and vitrectomized eyes of albino rabbits after intravenous administration of 100 mg/kg flomoxef sodium. The concentration of flomoxef sodium in the vitreous body was undetectable (< 0.1 micrograms/ml) in nonvitrectomized eyes. Retinal toxicity of flomoxef sodium was investigated with ophthalmoscopy, electroretinography (ERG) and light microscopy after intravitreal injection of 200, 500, 1,000 and 2,000 micrograms flomoxef sodium in albino and pigmented rabbits. No ERG changes were induced with 200 micrograms. Other higher doses caused transient ERG changes. After the 200-micrograms injection, the intravitreal concentration decreased exponentially, the half-life being 4.4 h. The antibacterial activity, broad coverage and low intravitreal toxicity of flomoxef sodium suggest that this compound may be used to treat bacterial endophthalmitis.

Norrin mediates neuroprotective effects on retinal ganglion cells via activation of the Wnt/beta-catenin signaling pathway and the induction of neuroprotective growth factors in Muller cells.

PubMed

Seitz, Roswitha; Hackl, Simon; Seibuchner, Thomas; Tamm, Ernst R; Ohlmann, Andreas

2010-04-28

Norrin is a secreted protein that binds to frizzled 4 and controls development of capillaries in retina and inner ear. We provide evidence that Norrin has distinct neuroprotective properties that are independent from its effects on vascular development. The function of Norrin was investigated in a mouse model of excitotoxic retinal ganglion cell (RGC) damage after intravitreal injection of NMDA, and in cultured Müller glia or immortalized RGC-5 cells. Intravitreal injection of Norrin significantly increased the number of surviving RGC axons in the optic nerve and decreased apoptotic death of retinal neurons following NMDA-mediated damage. This effect could be blocked by adding dickkopf (DKK)-1, an inhibitor of the Wnt/beta-catenin signaling pathway. Treatment of eyes with combined Norrin/NMDA activated Wnt/beta-catenin signaling and increased the retinal expression of leukemia inhibitory factor and endothelin-2, as well as that of neurotrophic growth factors such as fibroblast growth factor-2, brain-derived neurotrophic factor, lens epithelium-derived growth factor, and ciliary neurotrophic factor. A similar activation of Wnt/beta-catenin signaling and an increased expression of neurotrophic factors was observed in cultured Müller cells after treatment with Norrin, effects that again could be blocked by adding DKK-1. In addition, conditioned cell culture medium of Norrin-treated Müller cells increased survival of differentiated RGC-5 cells. We conclude that Norrin has pronounced neuroprotective properties on retinal neurons with the distinct potential to decrease the damaging effects of NMDA-induced RGC loss. The effects of Norrin involve activation of Wnt/beta-catenin signaling and subsequent induction of neurotrophic growth factors in Müller cells.

Comparison of treatment regimens for cytomegalovirus retinitis in patients with AIDS in the era of highly active antiretroviral therapy.

PubMed

Jabs, Douglas A; Ahuja, Alka; Van Natta, Mark; Dunn, J P; Yeh, Steven

2013-06-01

To describe the outcomes of different treatment approaches for cytomegalovirus (CMV) retinitis in the era of highly active antiretroviral therapy (HAART). Prospective cohort study, the Longitudinal Study of the Ocular Complications of AIDS. A total of 250 patients with CMV retinitis and a CD4+ T-cell count <100 cells/μl (n = 221) at enrollment or incident retinitis (n = 29) during cohort follow-up. The effects of systemic therapy (vs. intraocular therapy only) on systemic outcomes and the effect of intraocular therapies (ganciclovir implants, intravitreal injections) on ocular outcomes were evaluated. Mortality, CMV dissemination, retinitis progression, and treatment side effects. Regimens containing systemic anti-CMV therapy were associated with a 50% reduction in mortality (adjusted hazard ratio [HR], 0.5; 95% confidence interval [CI], 0.3-0.7; P = 0.006), a 90% reduction in new visceral CMV disease (adjusted HR, 0.1; 95% CI, 0.04-0.4; P = 0.004), and among those with unilateral CMV retinitis at presentation, an 80% reduction in second eye disease (adjusted HR, 0.2; 95% CI, 0.1-0.5; P = 0.0005) when compared with those using only intraocular therapy (implants or injections). Compared with systemic treatment only, regimens containing intravitreal injections had greater rates of retinitis progression (adjusted HR, 3.4; P = 0.004) and greater visual field loss (for loss of one half of the normal field, adjusted HR, 5.5; P < 0.01). Intravitreal implants were not significantly better than systemic therapy (adjusted HR for progression, 0.5; P = 0.26; adjusted HR for loss of one half of the visual field, 0.5; P = 0.45), but the sample size was small. Hematologic and renal side effect rates were similar between those groups with and without systemic anti-CMV therapy. The rate of endophthalmitis was 0.017 per eye-year (EY) (95% CI, 0.006-0.05) among those treated with intravitreal injections and 0.01 per EY (95% CI, 0.002-0.04) among those treated with an implant. In the HAART era, systemic anti-CMV therapy, while there is immune compromise, seems to provide benefits in terms of longer survival and decreased CMV dissemination. Proprietary or commercial disclosure may be found after the references. Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

GluA2 trafficking is involved in apoptosis of retinal ganglion cells induced by activation of EphB/EphrinB reverse signaling in a rat chronic ocular hypertension model.

PubMed

Dong, Ling-Dan; Gao, Feng; Wang, Xiao-Han; Miao, Yanying; Wang, Shu-Yue; Wu, Yi; Li, Fang; Wu, Jihong; Cheng, Xiang-Lin; Sun, Xing-Huai; Yang, Xiong-Li; Wang, Zhongfeng

2015-04-01

EphB1, expressed in Müller cells, and ephrinB2, expressed in both Müller cells and retinal ganglion cells (RGCs), constitute an EphB/ephrinB reverse signaling in RGCs. Whether and how this reverse signaling is involved in RGC apoptosis in a rat chronic ocular hypertension (COH) model was investigated. In the COH model, both EphB1 and ephrinB2 were significantly increased and the reverse signaling was activated, which was accompanied by increased protein levels of phosphorylated (p) src, GluA2, and p-GluA2. Intravitreal injection of EphB2-Fc, an activator of ephrinB2, induced an increase in TUNEL-positive signals in normal retinae. A coimmunoprecipitation assay demonstrated direct interactions among ephrinB2, p-src, and GluA2. Moreover, in COH rats the expression of GluA2 proteins on the surface of retinal cells was decreased. Such GluA2 endocytosis could be prevented by preoperational intravitreal injection of 4-amino-3-(4-chlorophenyl)-1-(t-butyl)-1H-pyrazolo [3,4-d] pyrimidine (PP2), an inhibitor of src family tyrosine kinases, and possibly involved the protein interacting with C kinase 1 and phosphorylation of GluA2. In normal rats, intravitreal injection of EphB2-Fc caused changes in these protein levels similar to those observed in COH rats, which all could be avoided by preinjection of PP2. Patch-clamp experiments further showed that the current-voltage relationship of AMPA receptor-mediated EPSCs of RGCs exhibited stronger inward rectification in EphB2-Fc-injected rats. Furthermore, preinjection of PP2 or N-[3-[[4-[(3-aminopropyl)amino]butyl]amino]propyl]-1-naphthaleneacetamide trihydrochloride) (Naspm), a Ca(2+)-permeable GluA2-lacking AMPA receptor inhibitor, remarkably inhibited RGC apoptosis in either EphB2-Fc-injected or COH rats. Together, elevated GluA2 trafficking induced by activated EphB2/ephrinB2 reverse signaling likely contributes to RGC apoptosis in COH rats. Copyright © 2015 the authors 0270-6474/15/355409-13$15.00/0.

Reversible bull's-eye maculopathy associated with intravitreal fomivirsen therapy for cytomegalovirus retinitis.

PubMed

Stone, T W; Jaffe, G J

2000-08-01

To report two cases in which a bull's eye maculopathy developed after intravitreal injection of fomivirsen. Case reports. A 50-year-old man with acquired immunodeficiency syndrome (AIDS) and refractory cytomegalovirus retinitis developed bull's-eye pigmentary changes in the macula of the right eye after initiating therapy with fomivirsen (Vitravene; CIBA Vision, Atlanta, Georgia) intravitreal injections. These pigmentary changes resolved upon cessation of treatment. A 36-year-old man with AIDS and refractory bilateral cytomegalovirus retinitis developed bull's-eye pigmentary changes in both eyes during bilateral intravitreal treatment with fomivirsen. Vision was not affected. These changes resolved after treatment with fomivirsen was stopped. Fomivirsen, a new medication for the treatment of refractory cytomegalovirus retinitis, may cause a bull's-eye maculopathy in some patients. The bull's-eye maculopathy is reversible and does not appear to affect vision.

INTRAVITREAL VERSUS SUBRETINAL ADMINISTRATION OF RECOMBINANT TISSUE PLASMINOGEN ACTIVATOR COMBINED WITH GAS FOR ACUTE SUBMACULAR HEMORRHAGES DUE TO AGE-RELATED MACULAR DEGENERATION: An Exploratory Prospective Study.

PubMed

de Jong, Jan H; van Zeeburg, Elsbeth J T; Cereda, Matteo G; van Velthoven, Mirjam E J; Faridpooya, Koorosh; Vermeer, Koenraad A; van Meurs, Jan C

2016-05-01

Current management of submacular hemorrhage (SMH) favors vitrectomy and gas with subretinal administration of recombinant tissue plasminogen activator (rtPA) over mere intravitreal rtPA injections and gas. In this study, we aimed to compare the effectiveness of both treatment modalities to displace submacular blood. Twenty-four patients with SMH secondary to age-related macular degeneration were included. The SMH had to exist ≤14 days at time of surgery and SMH thickness had to be between 250 μm and 1,250 μm. Patients were randomized to either intravitreal injections of rtPA, perfluoropropane (C3F8) gas, and bevacizumab (n = 12) or vitrectomy with subretinal rtPA administration, intravitreal C3F8 gas, and bevacizumab (n = 12). The SMH volume change was measured on spectral domain optical coherence tomography postoperatively within a 2.5-mm cylinder centered at the fovea. Median relative volume reduction of subretinal blood at 6 weeks postoperatively was 97% (95% confidence interval: 91-99%) in the intravitreal rtPA group and 100% (95-100%) in the subretinal rtPA group and did not differ significantly between groups (P = 0.56). Both treatment modalities effectively displaced SMH in this exploratory clinical trial. To more definitely study the noninferiority of intravitreal rtPA with gas to subretinal rtPA, vitrectomy with gas, a larger clinical trial would be necessary.

Combined application of BDNF to the eye and brain enhances ganglion cell survival and function in the cat after optic nerve injury.

PubMed

Weber, Arthur J; Viswanáthan, Suresh; Ramanathan, Chidambaram; Harman, Christine D

2010-01-01

To determine whether application of BDNF to the eye and brain provides a greater level of neuroprotection after optic nerve injury than treatment of the eye alone. Retinal ganglion cell survival and pattern electroretinographic responses were compared in normal cat eyes and in eyes that received (1) a mild nerve crush and no treatment, (2) a single intravitreal injection of BDNF at the time of the nerve injury, or (3) intravitreal treatment combined with 1 to 2 weeks of continuous delivery of BDNF to the visual cortex, bilaterally. Relative to no treatment, administration of BDNF to the eye alone resulted in a significant increase in ganglion cell survival at both 1 and 2 weeks after nerve crush (1 week, 79% vs. 55%; 2 weeks, 60% vs. 31%). Combined treatment of the eye and visual cortex resulted in a modest additional increase (17%) in ganglion cell survival in the 1-week eyes, a further significant increase (55%) in the 2-week eyes, and ganglion cell survival levels for both that were comparable to normal (92%-93% survival). Pattern ERG responses for all the treated eyes were comparable to normal at 1 week after injury; however, at 2 weeks, only the responses of eyes receiving the combined BDNF treatment remained so. Although treatment of the eye alone with BDNF has a significant impact on ganglion cell survival after optic nerve injury, combined treatment of the eye and brain may represent an even more effective approach and should be considered in the development of future optic neuropathy-related neuroprotection strategies.

Systemic and kidney toxicity of intraocular administration of vascular endothelial growth factor inhibitors.

PubMed

Pellé, Gaëlle; Shweke, Nasim; Duong Van Huyen, Jean-Paul; Tricot, Leïla; Hessaïne, Sadika; Frémeaux-Bacchi, Véronique; Hiesse, Christian; Delahousse, Michel

2011-05-01

Intravenous injection of angiogenesis-inhibitor drugs is used widely to treat cancers. Associated renal complications primarily involve proteinuria and hypertension, and thrombotic microangiopathies also have been described. Intravitreal anti-vascular endothelial growth factor (VEGF) therapy currently is used by ophthalmologists to treat neovascularization in age-related macular degeneration. However, there is some evidence that intravitreal anti-VEGF injections may result in systemic absorption, with the potential for injury in organs that are reliant on VEGF, such as the kidney. We report the first case to our knowledge of a patient who developed an acute decrease in kidney function, nonimmune microangiopathic hemolytic anemia with schistocytes, and thrombocytopenia after 4 intravitreal injections of ranibizumab. Light microscopy of a kidney biopsy specimen showed segmental duplications of glomerular basement membranes with endothelial swelling and several recanalized arteriolar thrombi. Because of the increasing use of intravitreal anti-VEGF agents, ophthalmologists and nephrologists should be aware of the associated risk of kidney disease. Early detection is crucial so that intravitreal injections can be stopped before severe kidney disease occurs. Copyright © 2011 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Therapeutic efficacy of intravitreal bevacizumab on posterior uveitis complicated by neovascularization

PubMed Central

Kurup, Shree; Lew, Julie; Byrnes, Gordon; Yeh, Steven; Nussenblatt, Robert; Levy-Clarke, Grace

2010-01-01

Purpose To evaluate the therapeutic effect of intravitreal bevacizumab in patients with uveitis-associated choroidal/retinal neovascularization. Methods Two female patients (40 years, 15 years) with posterior uveitis, (one presumed ocular sarcoidosis, one lupus) were evaluated for neovascularization of the posterior segment. Both patients were given a single dose of 1.25 mg intravitreal bevacizumab. Results Significant anatomical and functional recovery was evident in both patients within a few weeks. Conclusion In selected uveitic patients, bevacizumab may be an option for managing neovascularization. PMID:18513266

Ocular silicon distribution and clearance following intravitreal injection of porous silicon microparticles

PubMed Central

Nieto, Alejandra; Hou, Huiyuan; Sailor, Michael J.; Freeman, William R.; Cheng, Lingyun

2013-01-01

Porous silicon (pSi) microparticles have been investigated for intravitreal drug delivery and demonstrated good biocompatibility. With the appropriate surface chemistry, pSi can reside in vitreous for months or longer. However, ocular distribution and clearance pathway of its degradation product, silicic acid, are not well understood. In the current study, rabbit ocular tissue was collected at different time point following fresh pSi (day 1, 5, 9, 16, and 21) or oxidized pSi (day 3, 7, 14, 21, and 35) intravitreal injection. In addition, dual-probe simultaneous microdialysis of aqueous and vitreous humor was performed following a bolus intravitreal injection of 0.25 mL silicic acid (150 μg/mL) and six consecutive microdialysates were collected every 20 min. Silicon was quantified from the samples using inductively coupled plasma-optical emission spectroscopy. The study showed that following the intravitreal injection of oxidized pSi, free silicon was consistently higher in the aqueous than in the retina (8.1 ± 6.5 vs. 3.4 ± 3.9 μg/mL, p = 0.0031). The area under the concentration-time curve (AUC) of the retina was only about 24% that of the aqueous. The mean residence time was 16 days for aqueous, 13 days for vitreous, 6 days for retina, and 18 days for plasma. Similarly, following intravitreal fresh pSi, free silicon was also found higher in aqueous than in retina (7 ± 4.7 vs. 3.4 ± 4.1 μg/mL, p = 0.014). The AUC for the retina was about 50% of the AUC for the aqueous. The microdialysis revealed the terminal half-life of free silicon in the aqueous was 30 min and 92 min in the vitreous; the AUC for aqueous accounted for 38% of the AUC for vitreous. Our studies indicate that aqueous humor is a significant pathway for silicon egress from the eye following intravitreal injection of pSi crystals. PMID:24036388

Suspected bacterial endophthalmitis following sustained-release dexamethasone intravitreal implant: a case report.

PubMed

Arıkan Yorgun, Mücella; Mutlu, Melek; Toklu, Yasin; Cakmak, Hasan Basri; Cağıl, Nurullah

2014-06-01

A 58-year-old man admitted to our opthalmology department with the complaint of branch retinal vein occlusion. He was treated with intravitreal Ozurdex in the right eye. Two days after the injection, the patient presented with ocular pain and the visual acuity was hand movement. A diagnosis of endophthalmitis was made. We performed emergent pars plana vitrectomy (PPV) and the implant was removed from the vitreous cavity using a retinal forceps. A combination of vancomycin 1.0 mg and amikacin 0.4 mg was injected intravitreally. However, because of the blurring in the vitreus one week after the procedure, phacoemulsification and a repeat PPV was performed. Five days after the last procedure the signs and symptoms of endophthalmitis were resolved. Our case demonstrated that endophthalmitis could develop after intravitreal implantation of Ozurdex. Surgical removal of the implant and immediate vitrectomy seems to be a useful treatment option in these cases.

Intravitreal dexamethasone implants for the treatment of refractory scleritis combined with uveitis in adult-onset Still's disease: a case report.

PubMed

Ahn, Seong Joon; Hwang, Sun Jin; Lee, Byung Ro

2016-11-08

Adult-onset Still's disease is a systemic inflammatory disease which presents with uveitis and scleritis in the eye. Intravitreal dexamethasone implants are used for the treatment of refractory uveitis. A 19-year-old woman diagnosed to have adult-onset Still's disease for fevers, joint pain, and a salmon-colored bumpy rash presented with scleritis and uveitis in the left eye. Topical and systemic steroids with oral methotrexate failed to control the inflammation. We performed intravitreal injections of dexamethasone implants for side effects of steroid and refractory ocular inflammation. The therapy resulted in improvements in the patient's uveitis with reductions in scleral vessel engorgement and redness. There was no recurrence of uveitis or scleritis during 4 months following treatment. Intravitreal injections of dexamethasone implants may result in clinical improvements of refractory scleritis combined with uveitis.

Retinal hypoxia induces vascular endothelial growth factor through induction of estrogen-related receptor γ

DOE Office of Scientific and Technical Information (OSTI.GOV)

Do, Ji Yeon; Choi, Young Keun; Kook, Hyun

2015-05-01

Ischemic retinopathies causing overexpression of pro-angiogenic factors, including vascular endothelial growth factor (VEGF), are the most common cause of blindness. Thus, understanding the pathophysiology of targetable pathways that regulate retinal VEGF is of great interest. A conserved binding site for estrogen-related receptor γ (ERRγ) has been identified in the promoter of the Vegfa gene. ERRγ is a constitutively active orphan nuclear receptor and its expression is increased by hypoxic stimuli in metabolically active tissues. This study evaluated the role of ERRγ in the ischemic retina and the anti-VEGF potential of GSK5182, a selective inverse agonist of ERRγ. In an oxygen-inducedmore » retinopathy (OIR) mouse model, immunohistochemistry showed significantly increased ERRγ expression in the ganglion cell layer at postnatal day (P) 17. In a ganglion cell line (RGC-5), mRNA and protein levels of ERRγ were increased by desferrioxamine treatment and hypoxic conditions (1% O{sub 2}). Transient transfection of RGC-5 cells revealed that ERRγ regulated Vegfa expression and this was inhibited by GSK5182. Intravitreal injection of GSK5182 into the OIR model at P14 inhibited retinal Vegfa mRNA expression at P17. GSK5182 suppresses hypoxia-induced VEGF expression via ERRγ; therefore, ERRγ could be a treatment target for ischemic retinopathies. - Highlights: • OIR mice exhibited increased ERRγ expression in the ganglion cell layer. • Hypoxia-induced ERRγ expression was observed in retinal ganglion cells. • ERRγ overexpression increased VEGFA expression in retinal ganglion cells. • An ERRγ inverse agonist suppressed VEGFA expression in retinal ganglion cells. • Intravitreal injection of an ERRγ inverse agonist suppressed VEGFA in OIR mice.« less

Treatment of cytomegalovirus (CMV) retinitis with intravitreous ganciclovir in HIV-infected children.

PubMed

Surachatkumtonekul, Thammanoon; Chokephaibulkit, Kulkanya; Vanprapar, Nirun; Pamonvaechavan, Pittaya

2008-03-01

To evaluate the efficacy, visual outcomes, and complications of intravitreous ganciclovir treatment in cytomegalovirus (CMV) retinitis in HIV-infected children. The medical records of HIV-infected children who were screened for CMV retinitis from February 2002 to February 2005 were reviewed. The children with CD4+ < 15%, or with clinical category C would have complete ophthalmic examination every 3 months. Ganciclovir (4 mg/0.04 ml) was administered intravitreously to the eye with CMV retinitis every 2 weeks under general anaesthesia. After injection, fundi were examined immediately, 1 day, 14 days and every 2 weeks until the lesions were stable. Six (9 eyes) out of 45 children (13%) aged 2-12 years were found to have CMV retinitis. All CMV retinitis lesions were "cheese and ketchup like" (retinal hemorrhage and exudate) lesions and presented in the posterior pole. Bilateral CMV retinitis were found in 3 children. Intravitreous ganciclovir was injected in 4 children (5 eyes). The average number of intravitreous injections for each patient was 5.6 (3-7) times. All of the children received antiretroviral therapy and 3 children also received intravenous ganciclovir CMV retinitis lesions were improved in every eye. The visual acuity (VA) remained stable in 4 eyes, but endophthalmitis developed in one eye a few days after injection. The average duration of follow-up was 13.5 months (3-23 months). CMV retinitis was not uncommon. The authors found that intravitreous ganciclovir was effective but may cause complications. This treatment should be considered in a resource-limited setting.

Quantitative evaluation of hard exudates in diabetic macular edema after short-term intravitreal triamcinolone, dexamethasone implant or bevacizumab injections.

PubMed

Shin, Yong Un; Hong, Eun Hee; Lim, Han Woong; Kang, Min Ho; Seong, Mincheol; Cho, Heeyoon

2017-10-03

To quantitatively compare short-term hard exudates (HEs) alteration in patients with diabetic macular edema (DME) after intravitreal triamcinolone, dexamethasone implant or bevacizumab injections. This retrospective study enrolled DME eyes with HEs that underwent a single-dose intravitreal injection of triamcinolone (25 eyes), dexamethasone implant (20 eyes), or three monthly injections of bevacizumab (25 eyes) and completed at least three months of follow-up. All patients were examined before and after 1, 2 and 3 months of injections. Using color fundus photographs, the amount of HEs was quantified by two masked graders. The difference in HEs area between baseline and each follow-up visit was compared among the three groups. After three months, HEs area was reduced to 52.9 ± 4.21% (P < 0.001) in the triamcinolone group, 63.6 ± 6.08% (P = 0.002) in the dexamethasone implant group, and 85.2 ± 5.07% (P = 0.198) in the bevacizumab group. A significant reduction in HEs appeared at one month in the triamcinolone group (53.5 ± 4.91%, P < 0.001) and at two months in the dexamethasone implant group (70.1 ± 5.21%, P = 0.039). Our study suggests intravitreal steroids (triamcinolone, dexamethasone implants) significantly reduce HEs in DME patients on short-term follow-up, whereas intravitreal bevacizumab does not. Therefore, intravitreal steroids may be useful in DME with HEs in the fovea.

Accelerated ischemic vascular retinopathy after intravitreally injected bevacizumab for central retinal vein occlusion in elderly patients

PubMed Central

Isola, Vincenzo; Pece, Alfredo; Massironi, Claudio; Reposi, Simone; Dimastrogiovanni, Fabio

2013-01-01

Background: Ischemic changes in the retinal circulation are an uncommon but severe adverse vascular reaction to intravitreal bevacizumab (Avastin®, Genentech, San Francisco, CA, USA/Roche, Basel, Switzerland) for central retinal vein occlusion (CRVO). In the two cases reported here, ischemic changes in the retina vasculature following intravitreal bevacizumab for CRVO were observed with the aim of describing the clinical and angiographic features of these changes. Methods: Two elderly patients with recent-onset CRVO received one off-label intravitreal injection of bevacizumab 0.05 mL/1.25 mg. Results: In Case 1, the patient’s pre-treatment visual acuity was 20/400. At 3 weeks post injection, the patient could count fingers at a distance of 1 ft (30 cm) and fluorescein angiography showed reduction in intraretinal hemorrhages and areas of retinal non-perfusion. However, at 6 weeks these were markedly increased compared with those seen in the photograph taken 3 weeks after treatment. In Case 2, the patient’s pre-treatment visual acuity was 20/200. At 1 month post injection, vision had decreased to 20/400 and fluorescein angiography showed severe macular ischemia with a remarkable capillary dropout throughout the macula. Conclusion: Ischemic retinal injury may be an uncommon but severe adverse vascular reaction to intravitreal bevacizumab for CRVO. Although progression of retinal ischemia in CRVO could be observed shortly after intravitreal bevacizumab, whether this is a drug- or procedure-related effect or part of the natural history of the condition remains uncertain. PMID:23467497

Exploratory analysis of the effect of intravitreal ranibizumab or triamcinolone on worsening of diabetic retinopathy in a randomized clinical trial.

PubMed

Bressler, Susan B; Qin, Haijing; Melia, Michele; Bressler, Neil M; Beck, Roy W; Chan, Clement K; Grover, Sandeep; Miller, David G

2013-08-01

The standard care for proliferative diabetic retinopathy (PDR) usually is panretinal photocoagulation, an inherently destructive treatment that can cause iatrogenic vision loss. Therefore, evaluating the effects of therapies for diabetic macular edema on development or worsening of PDR might lead to new therapies for PDR. To evaluate the effects of intravitreal ranibizumab or triamcinolone acetonide, administered to treat diabetic macular edema, on worsening of diabetic retinopathy. Exploratory analysis was performed on worsening of retinopathy, defined as 1 or more of the following: (1) worsening from no PDR to PDR, (2) worsening of 2 or more severity levels on reading center assessment of fundus photographs in eyes without PDR at baseline, (3) having panretinal photocoagulation, (4) experiencing vitreous hemorrhage, or (5) undergoing vitrectomy for the treatment of PDR. Community- and university-based ophthalmology practices. Individuals with central-involved diabetic macular edema causing visual acuity impairment. Eyes were assigned randomly to sham with prompt focal/grid laser, 0.5 mg of intravitreal ranibizumab with prompt or deferred (≥24 weeks) laser, or 4 mg of intravitreal triamcinolone acetonide with prompt laser. Three-year cumulative probabilities for retinopathy worsening. For eyes without PDR at baseline, the 3-year cumulative probabilities for retinopathy worsening (P value comparison with sham with prompt laser) were 23% using sham with prompt laser, 18% with ranibizumab with prompt laser (P = .25), 7% with ranibizumab with deferred laser (P = .001), and 37% with triamcinolone with prompt laser (P = .10). For eyes with PDR at baseline, the 3-year cumulative probabilities for retinopathy worsening were 40%, 21% (P = .05), 18% (P = .02), and 12% (P < .001), respectively. CONCLUSIONS AND RELEVANCE Intravitreal ranibizumab appears to be associated with a reduced risk of diabetic retinopathy worsening in eyes with or without PDR. Intravitreal triamcinolone also appears to be associated with a reduced risk of PDR worsening. These findings suggest that use of these drugs to prevent worsening of diabetic retinopathy may be feasible. Given the exploratory nature of these analyses, the risk of endophthalmitis following intravitreal injections, and the fact that intravitreal triamcinolone can cause cataract or glaucoma, use of these treatments to reduce the rates of worsening of retinopathy, with or without PDR, does not seem warranted at this time.

Role of receptor-mediated endocytosis in the antiangiogenic effects of human T lymphoblastic cell-derived microparticles.

PubMed

Yang, Chun; Xiong, Wei; Qiu, Qian; Shao, Zhuo; Shao, Zuo; Hamel, David; Tahiri, Houda; Leclair, Grégoire; Lachapelle, Pierre; Chemtob, Sylvain; Hardy, Pierre

2012-04-15

Microparticles possess therapeutic potential regarding angiogenesis. We have demonstrated the contribution of apoptotic human CEM T lymphocyte-derived microparticles (LMPs) as inhibitors of angiogenic responses in animal models of inflammation and tumor growth. In the present study, we characterized the antivascular endothelial growth factor (VEGF) effects of LMPs on pathological angiogenesis in an animal model of oxygen-induced retinopathy and explored the role of receptor-mediated endocytosis in the effects of LMPs on human retinal endothelial cells (HRECs). LMPs dramatically inhibited cell growth of HRECs, suppressed VEGF-induced cell migration in vitro experiments, and attenuated VEGF-induced retinal vascular leakage in vivo. Intravitreal injections of fluorescently labeled LMPs revealed accumulation of LMPs in retinal tissue, with more than 60% reductions of the vascular density in retinas of rats with oxygen-induced neovascularization. LMP uptake experiments demonstrated that the interaction between LMPs and HRECs is dependent on temperature. In addition, endocytosis is partially dependent on extracellular calcium. RNAi-mediated knockdown of low-density lipoprotein receptor (LDLR) reduced the uptake of LMPs and attenuated the inhibitory effects of LMPs on VEGF-A protein expression and HRECs cell growth. Intravitreal injection of lentivirus-mediated RNA interference reduced LDLR protein expression in retina by 53% and significantly blocked the antiangiogenic effects of LMPs on pathological vascularization. In summary, the potent antiangiogenic LMPs lead to a significant reduction of pathological retinal angiogenesis through modulation of VEGF signaling, whereas LDLR-mediated endocytosis plays a partial, but pivotal, role in the uptake of LMPs in HRECs.

Intravitreal injection of exendin-4 analogue protects retinal cells in early diabetic rats.

PubMed

Zhang, Yu; Zhang, Jingfa; Wang, Qingping; Lei, Xia; Chu, Qing; Xu, Guo-Tong; Ye, Wen

2011-01-05

To evaluate the protective effect of intravitreal injection of exendin-4 analogue (E4a) in early diabetic retinopathy (DR) and to explore its possible mechanism. Forty Sprague-Dawley rats were divided into three groups: normal (N), diabetic (D), and E4a-treated diabetic rats (E4a). Diabetes was induced by streptozotocin. Rats in the E4a group were treated with E4a (0.1 μg/2μL/eye), whereas the N and D groups were treated with the equivalent volume of normal saline. Electroretinography was performed at 1 month and 3 months after diabetes onset. Thicknesses and cell counts in each layer of the retina were evaluated. The concentration of glutamate was measured by high-performance liquid chromatography (HPLC). Expressions of glucagon-like peptide-1 receptor (GLP-1R) and GLAST (excitatory amino acid transporter) were detected at mRNA and protein levels and verified by immunohistochemistry in vitro and in vivo. The rMc-1 cells were cultured under high-glucose medium (25 mM), which mimicked diabetic conditions. Effects of E4a (10 μg/mL) were also tested in the rMc-1 culture system. E4a prevented the reduction in b-wave amplitude and oscillatory potential amplitude caused by diabetes. It also prevented the cell loss of outer nuclear layer and inner nuclear layer; the thickness and cell count in the outer nuclear layer were decreased in 1-month diabetic rats. The concentration of glutamate in the retina was higher in diabetic rats and was significantly reduced in the E4a-treated group. Consistent with such changes, retinal GLP-1R and GLAST expression were reduced in the diabetic retina but upregulated in E4a-treated rats. No improvement was found in the retina in both functional and morphologic parameters 3 months after treatment. Intravitreal administration of E4a can prevent the retina, functionally and morphologically, from the insults of diabetes in rats. GLP-1R and GLAST were proved to exist in the rat retina, and their lowered expressions in the diabetic retina might be related to retinal damage by increasing the retinal glutamate. E4a might protect the retina by reducing the glutamate level through upregulating GLP-1R and GLAST, as observed in retinal Müller cells in this study, but this protective effect was transient. Thus, this could be a potential approach for the treatment of DR.

The efficacy of intravitreal interferon alpha-2b for the treatment of experimental endotoxin-induced uveitis.

PubMed

Afarid, Mehrdad; Lashkarizadeh, Hamid; Ashraf, Mohammad J; Nowroozzadeh, Mohammad Hossein; Shafiee, Sayed M

2016-05-01

To study the efficacy of intravitreal interferon alpha-2b for endotoxin-induced uveitis. A total of 36 rabbits were randomly allocated to one of the three groups: (1) received interferon plus balanced-salt solution; (2) received lipopolysaccharide (LPS) plus interferon; and (3) received LPS plus balanced-salt solution. Intraocular inflammation was evaluated by slit-lamp biomicroscopy (standardization of uveitis nomenclature grading), binocular indirect ophthalmoscopy (BIO) score, and histopathology. Group 2 showed significantly lower mean (±standard deviation) anterior chamber reaction than Group 3 (3.1 ± 0.9 vs. 3.8 ± 0.4) on day 1 postinjection, lower vitreous cells on days 1 through 7 (day 1: 3.1 ± 0.9 vs. 3.8 ± 0.4; day 3: 2.1 ± 1.6 vs. 3.8 ± 0.4; day 7: 1.9 ± 1.3 vs. 3.6 ± 0.7), and lower BIO score on days 1-7 (day 1: 3.3 ± 1.2 vs. 4.4 ± 0.7; day 3: 3.0 ± 1.4 vs. 4.3 ± 0.9; day 7: 2.4 ± 1.4 vs. 3.7 ± 1.2). The protein content of anterior and vitreous aspirates was lower in Group 2 than 3 (1618.5 ± 411.4 vs. 2567.3 ± 330.8 and 2157.0 ± 283.3 vs. 3204.6 ± 259.5, respectively). Intravitreal interferon alpha-2b was effective in controlling endotoxin-induced uveitis.

Nucleoside Reverse Transcriptase Inhibitors Suppress Laser-Induced Choroidal Neovascularization in Mice

PubMed Central

Mizutani, Takeshi; Fowler, Benjamin J.; Kim, Younghee; Yasuma, Reo; Krueger, Laura A.; Gelfand, Bradley D.; Ambati, Jayakrishna

2015-01-01

Purpose To evaluate the efficacy of nucleoside reverse transcriptase inhibitors (NRTIs) in the laser-induced mouse model of choroidal neovascularization (CNV). Methods We evaluated the NRTIs lamivudine (3TC), zidovudine (AZT), and abacavir (ABC) and the P2X7 antagonist A438079. Choroidal neovascularization was induced by laser injury in C57BL/6J wild-type, Nlrp3−/−, and P2rx7−/− mice, and CNV volume was measured after 7 days by confocal microscopy. Drugs were administered by intravitreous injection immediately after the laser injury. Vascular endothelial growth factor-A in RPE-choroid lysates was measured 3 days after laser injury by ELISA. HEK293 cells expressing human and mouse P2X7 were exposed to the selective P2X7 receptor agonist 2′, 3′-(benzoyl-4-benzoyl)-ATP (Bz-ATP) with or without 3TC, and VEGF-A levels in media were measured by ELISA. Results Intravitreous injection of 3TC, AZT, and ABC significantly suppressed laser-induced CNV in C57BL/6J wild-type and Nlrp3−/− mice (P < 0.05) but not in P2rx7−/− mice. Intravitreous injection of A438079 also suppressed the laser-induced CNV (P < 0.05). The NRTIs 3TC, AZT, and ABC blocked VEGF-A levels in the RPE/choroid after laser injury in wild-type (P < 0.05) but not P2rx7−/− mice. Moreover, there was no additive effect of 3TC on CNV inhibition when coadministered with a neutralizing VEGF-A antibody. Stimulation of human and mouse P2X7-expressing HEK293 cells with Bz-ATP increased VEGF secretion (P < 0.001), which was abrogated by 3TC (P < 0.001). Stimulation of primary human RPE cells with Bz-ATP increased VEGFA and IL6 mRNA levels, which were abrogated by 3TC. Conclusions Multiple clinically relevant NRTIs suppressed laser-induced CNV and downregulated VEGF-A, via P2X7. PMID:26529046

Involvement of P2X7 receptors in retinal ganglion cell apoptosis induced by activated Müller cells.

PubMed

Xue, Bo; Xie, Yuting; Xue, Ying; Hu, Nan; Zhang, Guowei; Guan, Huaijin; Ji, Min

2016-12-01

Müller cell reactivation (gliosis) is an early response in glaucomatous retina. Previous studies have demonstrated that activation of P2X 7 receptors results in retinal ganglion cell (RGC) apoptosis. Here, the issues of whether and how activated Müller cells may contribute to RGC apoptosis through P2X 7 receptors were investigated. Either intravitreal injection of (S)-3,5-dihydroxyphenylglycine (DHPG), a group I metabotropic glutamate receptor (mGluR I) agonist, in normal rat retinas, or DHPG treatment of purified cultured rat retinal Müller cells induced an increase in glial fibrillary acidic protein (GFAP) expression, indicative of Müller cell gliosis. In addition, an increase in adenosine triphosphate (ATP) release from purified cultured Müller cells was detected during DHPG treatment (for 10 min to 48 h), which was mediated by the intracellular mGluR5/Gq/PI-PLC/PKC signaling pathway. Intravitreal injection of DHPG mimicked the reduction in the number of fluorogold retrogradely labeled RGCs in chronic ocular hypertension (COH) rats. Treatment with the conditioned culture medium (CM) obtained from the DHPG-activated Müller cell medium induced an increase in the number of TUNEL-positive cells in cultured RGCs, which was mimicked by benzoylbenzoyl adenosine triphosphate (BzATP), a P2X 7 receptor agonist, but was partially blocked by brilliant blue G (BBG), a P2X 7 receptor antagonist. Moreover, the CM treatment of cultured RGCs significantly increased Bax protein level and decreased Bcl-2 protein level, which was also mimicked by BzATP and partially blocked by BBG, respectively. These results suggest that reactivated Müller cells may release excessive ATP, in turn leading to RGC apoptosis through activating P2X 7 receptors in these cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Endogenous Cryptococcus neoformans endophthalmitis with subretinal abscess in a HIV-infected man.

PubMed

Joseph, Joveeta; Sharma, Savitri; Narayanan, Raja

2018-07-01

To report a rare case of Cryptococcus neoformans endogenous endophthalmitis with subretinal abscess in a 36-year-old HIV-positive man, referred with progressive blurred vision in his right eye for the last 6 months. Vitreous biopsy followed by intravitreal ganciclovir did not result in significant improvement. Microbiology revealed the presence of C. neoformans, and intravitreal amphotericin B was then administered. The patient was treated aggressively with systemic and intravitreal antifungals but had a poor visual and anatomical outcome. A high degree of clinical suspicion combined with microbiological evaluation helped to arrive at an appropriate diagnosis.

Treatment of unilateral zone I cytomegalovirus retinitis in acute lymphoblastic leukemia with oral valganciclovir and intravitreal ganciclovir

PubMed Central

Tripathy, Koushik; Mittal, Kanhaiya; Venkatesh, Pradeep; Bakhshi, Sameer; Chawla, Rohan

2017-01-01

Cytomegalovirus retinitis (CMVR) is an opportunistic infection seen in immunocompromised patients, especially suffering from acquired immune deficiency syndrome. It is uncommonly seen in hematological malignancies and in patients on immunosuppressants. The authors present a 12-year-old girl with unilateral CMVR who was on maintenance phase therapy for mixed phenotype (B/myeloid) leukemia. Serology for human immunodeficiency virus was negative. The child was successfully treated with oral valganciclovir and repeated intravitreal ganciclovir injections. CMVR in pediatric population with leukemia can be successfully treated with oral valganciclovir and intravitreal ganciclovir injections. PMID:29118508

Ultrasound-mediated nanoparticle delivery across ex vivo bovine retina after intravitreal injection.

PubMed

Huang, Di; Chen, Ying-Shan; Thakur, Sachin S; Rupenthal, Ilva D

2017-10-01

Intravitreal injection is the most common administration route for the treatment of retinal diseases. However, the vitreous and some of the retinal layers themselves act as significant barriers to efficient delivery of drugs administered intravitreally. This study aimed to improve the diffusive mobility of nanoparticles (NPs) in the vitreous and enhance their permeation across the retina after intravitreal injection by application of ultrasound (US). Ex vivo posterior bovine eye cups were used and the vitreous was either left intact or removed gently from the neural retina. Hyaluronic acid coated human serum albumin NPs were administered into the eye cups and continuous US with a frequency of 1MHz, an intensity of 0.5W/cm 2 , and a duration of 30s was applied once or repeatedly via the transscleral route. After pre-determined time points, fluorescence intensities in the vitreous and the retina were analyzed. Short pulses of US significantly improved the diffusive mobility of NPs through the vitreous as well as their penetration across the neural retina into the retinal pigment epithelium and choroid without causing any detectable damage to the ocular tissues. Therefore, transscleral US could be a powerful and safe tool to enhance retinal delivery of intravitreally injected NPs. Copyright © 2017 Elsevier B.V. All rights reserved.

Intravitreally Injected Anti-VEGF Antibody Reduces Brown Fat in Neonatal Mice.

PubMed

Jo, Dong Hyun; Park, Sung Wook; Cho, Chang Sik; Powner, Michael B; Kim, Jin Hyoung; Fruttiger, Marcus; Kim, Jeong Hun

2015-01-01

Anti-vascular endothelial growth factor (VEGF) agents are the mainstay treatment for various angiogenesis-related retinal diseases. Currently, bevacizumab, a recombinant humanized anti-VEGF antibody, is trailed in retinopathy of prematurity, a vasoproliferative retinal disorder in premature infants. However, the risks of systemic complications after intravitreal injection of anti-VEGF antibody in infants are not well understood. In this study, we show that intravitreally injected anti-VEGF antibody is transported into the systemic circulation into the periphery where it reduces brown fat in neonatal C57BL/6 mice. A considerable amount of anti-VEGF antibody was detected in serum after intravitreal injection. Furthermore, in interscapular brown adipose tissue, we found lipid droplet accumulation, decreased VEGF levels, loss of vascular network, and decreased expression of mitochondria-related genes, Ppargc1a and Ucp1, all of which are characteristics of "whitening" of brown fat. With increasing age and body weight, brown fat restored its morphology and vascularity. Our results show that there is a transient, but significant impact of intravitreally administered anti-VEGF antibody on brown adipose tissue in neonatal mice. We suggest that more attention should be focused on the metabolic and developmental significance of brown adipose tissue in bevacizumab treated retinopathy of prematurity infants.

Intravitreally Injected Anti-VEGF Antibody Reduces Brown Fat in Neonatal Mice

PubMed Central

Powner, Michael B.; Kim, Jin Hyoung; Fruttiger, Marcus; Kim, Jeong Hun

2015-01-01

Anti-vascular endothelial growth factor (VEGF) agents are the mainstay treatment for various angiogenesis-related retinal diseases. Currently, bevacizumab, a recombinant humanized anti-VEGF antibody, is trailed in retinopathy of prematurity, a vasoproliferative retinal disorder in premature infants. However, the risks of systemic complications after intravitreal injection of anti-VEGF antibody in infants are not well understood. In this study, we show that intravitreally injected anti-VEGF antibody is transported into the systemic circulation into the periphery where it reduces brown fat in neonatal C57BL/6 mice. A considerable amount of anti-VEGF antibody was detected in serum after intravitreal injection. Furthermore, in interscapular brown adipose tissue, we found lipid droplet accumulation, decreased VEGF levels, loss of vascular network, and decreased expression of mitochondria-related genes, Ppargc1a and Ucp1, all of which are characteristics of “whitening” of brown fat. With increasing age and body weight, brown fat restored its morphology and vascularity. Our results show that there is a transient, but significant impact of intravitreally administered anti-VEGF antibody on brown adipose tissue in neonatal mice. We suggest that more attention should be focused on the metabolic and developmental significance of brown adipose tissue in bevacizumab treated retinopathy of prematurity infants. PMID:26226015

Neuroprotection of a Novel Cyclopeptide C*HSDGIC* from the Cyclization of PACAP (1–5) in Cellular and Rodent Models of Retinal Ganglion Cell Apoptosis

PubMed Central

Cheng, Huanhuan; Ding, Yong; Yu, Rongjie; Chen, Jiansu; Wu, Chunyun

2014-01-01

Purpose To investigate the protective effects of a novel cyclopeptide C*HSDGIC* (CHC) from the cyclization of Pituitary adenylate cyclase-activating polypeptide (PACAP) (1–5) in cellular and rodent models of retinal ganglion cell apoptosis. Methodology/Principal Findings Double-labeling immunohistochemistry was used to detect the expression of Thy-1 and PACAP receptor type 1 in a retinal ganglion cell line RGC-5. The apoptosis of RGC-5 cells was induced by 0.02 J/cm2 Ultraviolet B irradiation. MTT assay, flow cytometry, fluorescence microscopy were used to investigate the viability, the level of reactive oxygen species (ROS) and apoptosis of RGC-5 cells respectively. CHC attenuated apoptotic cell death induced by Ultraviolet B irradiation and inhibited the excessive generation of ROS. Moreover, CHC treatment resulted in decreased expression of Bax and concomitant increase of Bcl-2, as was revealed by western-blot analysis. The in vivo apoptosis of retinal ganglion cells was induced by injecting 50 mM N-methyl-D-aspartate (NMDA) (100 nmol in a 2 µL saline solution) intravitreally, and different dosages of CHC were administered. At day 7, rats in CHC+ NMDA-treated groups showed obvious aversion to light when compared to NMDA rats. Electroretinogram recordings revealed a marked decrease in the amplitudes of a-wave, b-wave, and photopic negative response due to NMDA damage. In retina receiving intravitreal NMDA and CHC co-treatment, these values were significantly increased. CHC treatment also resulted in less NMDA-induced cell loss and a decrease in the proportion of dUTP end-labeling-positive cells in ganglion cell line. Conclusions C*HSDGIC*, a novel cyclopeptide from PACAP (1–5) attenuates apoptosis in RGC-5 cells and inhibits NMDA-induced retinal neuronal death. The beneficial effects may occur via the mitochondria pathway. PACAP derivatives like CHC may serve as a promising candidate for neuroprotection in glaucoma. PMID:25286089

Platelet-Derived Growth Factor-BB Lessens Light-Induced Rod Photoreceptor Damage in Mice.

PubMed

Takahashi, Kei; Shimazawa, Masamitsu; Izawa, Hiroshi; Inoue, Yuki; Kuse, Yoshiki; Hara, Hideaki

2017-12-01

Platelet-derived growth factor (PDGF)-BB is known to have neuroprotective effects against various neurodegenerative disorders. The purpose of this study was to determine whether PDGF-BB can be neuroprotective against light-induced photoreceptor damage in mice. Mice were exposed to 8000-lux luminance for 3 hours to induce phototoxicity. Two hours before light exposure, the experimental mice were injected with PDGF-BB intravitreally, and the control mice were injected with phosphate-buffered saline. The light-exposed PDGF-BB-injected mice and saline-injected mice were evaluated electroretinographically and histologically. The site and expression levels of PDGFR-β and PDGF-BB were determined by immunostaining and Western blotting, respectively. The effect of PDGF-BB on light-induced cone and rod photoreceptor damage was also evaluated in vitro in 661W cells, a murine cone photoreceptor cell line, and in primary retinal cell cultures. An intravitreal injection of PDGF-BB significantly reduced the decrease in the amplitudes of the electroretinograms (ERGs) and the thinning of the outer nuclear layer (ONL) induced by the light exposure. It also reduced the number of TUNEL-positive cells in the ONL. PDGFR-β was expressed in the rod outer segments (OSs) but not the cone OSs. The levels of PDGF-BB and PDGFR-β were decreased after light irradiation. In addition, PDGF-BB had protective effects against light-induced damage to cells of rod photoreceptors but had no effect on the 661W cells in vitro. These findings indicate that PDGF-BB reduces the degree of light-induced retinal damage by activating PDGFR-β in rod photoreceptors. These findings suggest that PDGF-BB could play a role in the prevention of degeneration in eyes susceptible to phototoxicity.

Intravitreal injection of forskolin, homotaurine, and L-carnosine affords neuroprotection to retinal ganglion cells following retinal ischemic injury

PubMed Central

Adornetto, Annagrazia; Cavaliere, Federica; Varano, Giuseppe Pasquale; Rusciano, Dario; Morrone, Luigi Antonio; Corasaniti, Maria Tiziana; Bagetta, Giacinto; Nucci, Carlo

2015-01-01

Purpose Retinal ganglion cell (RGC) death is the final event leading to visual impairment in glaucoma; therefore, identification of neuroprotective strategies able to slow down or prevent the process is one of the main challenges for glaucoma research. The purpose of this study was to evaluate the neuroprotective potential of RGC death induced by the in vivo transient increase in intraocular pressure (IOP) of a combined treatment with forskolin, homotaurine, and L-carnosine. Forskolin (7beta-acetoxy-8, 13-epoxy-1a, 6β, 9a-trihydroxy-labd-14-en-11-one) is an activator of adenylate cyclase that decreases IOP by reducing aqueous humor production and functions as a neuroprotector due to its neurotrophin-stimulating activity. Homotaurine is a natural aminosulfonate compound endowed with neuromodulatory effects, while the dipeptide L-carnosine is known for its antioxidant properties. Methods Retinal ischemia was induced in the right eye of adult male Wistar rats by acutely increasing the IOP. Forskolin, homotaurine, and L-carnosine were intravitreally injected and RGC survival evaluated following retrograde labeling with FluoroGold. Total and phosphorylated Akt and glycogen synthase kinase-3β (GSK-3β) protein levels, as well as calpain activity, were analyzed with western blot. Protein kinase A (PKA) was inhibited by intravitreal injection of H89. Results A synergic neuroprotective effect on RGC survival was observed following the combined treatment with forskolin, homotaurine, and L-carnosine compared to forskolin alone. The observed neuroprotection was associated with reduced calpain activity, upregulation of phosphoinositide 3-kinase (PI3K)/Akt pathway, and inhibition of GSK-3β but was independent from PKA activation and distinct from the hypotensive effects of forskolin. Conclusions A multidrug/multitarget approach, by interfering with several pathways involved in RGC degeneration, may be promising to achieve glaucoma neuroprotection. PMID:26167113

Characteristics of patients with neovascular age-related macular degeneration who are non-responders to intravitreal aflibercept.

PubMed

Hara, Chikako; Wakabayashi, Taku; Toyama, Hiroshi; Fukushima, Yoko; Sayanagi, Kaori; Sato, Shigeru; Sakaguchi, Hirokazu; Nishida, Kohji

2018-06-15

To investigate the frequency and patient characteristics that influence anatomic response of intravitreal aflibercept in treatment-naïve neovascular age-related macular degeneration (AMD). Retrospective, interventional, consecutive case series. Three hundred and sixty-five eyes of 365 patients with AMD who underwent 3 monthly intravitreal aflibercept treatments with follow-up for at least 12 months were investigated. Treatment response was evaluated as follows. Responders were defined as those with complete resolution of exudation, including intraretinal oedema, subretinal fluid and pigment epithelial detachment, or more than a 100 µm decrease of central retinal thickness at 3 months compared with baseline. Non-responders were defined as patients exhibiting an increase in exudation or a decreased central retinal thickness of less than 100 µm. Nineteen (5.2%) of 365 eyes were identified as non-responders. The remaining were responders to intravitreal aflibercept. The non-responders group was significantly associated with choroidal vascular hyperpermeability on indocyanine green angiography and lower frequency of subretinal hyper-reflective materials on optical coherence tomography. The central choroidal thickness at baseline and after 3 monthly injections tended to be thicker in the non-responder group than the responder group, although the differences did not meet statistical significance (p=0.066 and p=0.051, respectively). Additional treatments with either intravitreal ranibizumab or PDT in combination with aflibercept were effective in 15 (79%) of 19 non-responders. Intravitreal aflibercept is effective for treating eye pathology in most naïve AMD cases. However, non-responsiveness may occur in small subgroup of patients with choroidal vascular hyperpermeability. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Effect of Intravitreal Bevacizumab on Vascular Endothelial Growth Factor Expression in Patients with Proliferative Diabetic Retinopathy

PubMed Central

Chung, Eun Jee; Kang, Shin Jeong; Koo, Ja Seung; Choi, Yoon Jung; Grossniklaus, Hans E.

2011-01-01

Purpose To investigate the effect of bevacizumab (Avastin; Genentech, San Francisco, CA, USA) on vascular endothelial growth factor (VEGF) expression and inflammation in fibrovascular membranes in patients with proliferative diabetic retinopathy (PDR). Materials and Methods Fibrovascular membranes from 19 eyes of 18 patients with PDR were studied using immunohistochemistry and analyzed in the following 3 groups; group 1: 4 inactive PDR eyes, group 2: 10 active PDR eyes treated preoperatively with adjunctive intravitreal bevacizumab, group 3: five active PDR eyes not treated preoperatively with bevacizumab. Immunohistochemical staining for VEGF, CD31 and CD68 were done. Results The immunoreactivity to VEGF and CD 31-positive blood vessels was significantly higher in membranes from group 3 than group 1 (p = 0.007 for VEGF, 0.013 for CD 31-positive vessels). Intravitreal bevacizumab caused a reduction in VEGF expression and vascular densities in 4 out of 10 (40%) excised membranes from eyes with PDR. However, six membranes (60%) in group 2 still demonstrated relatively strong VEGF expression and high vascular density. Infiltration of macrophages was observed in 16 out of the 19 membranes, and the density of macrophages was increased in group 2 compared with group 1 (p = 0.043). Conclusion Intravitreal bevacizumab injections caused some reduction in VEGF expression and vascular densities in a limited number of active PDR patients. A single intravitreal bevacizumab injection may not be enough to induce complete blockage of VEGF and pathologic neovascularization in active PDR patients. Repeated injections, panretinal photocoagulation and/or PPV may be necessary following intravitreal bevacizumab to reinforce the anti-VEGF effect of the drug. PMID:21155048

Types of Stem Cells

MedlinePlus

... Cell Glossary Search Toggle Nav Types of Stem Cells Stem cells are the foundation from which all ... About Stem Cells > Types of Stem Cells Stem cells Stem cells are the foundation for every organ ...

miRNA-regulated cancer stem cells: understanding the property and the role of miRNA in carcinogenesis.

PubMed

Chakraborty, Chiranjib; Chin, Kok-Yong; Das, Srijit

2016-10-01

Over the last few years, microRNAs (miRNA)-controlled cancer stem cells have drawn enormous attention. Cancer stem cells are a small population of tumor cells that possess the stem cell property of self-renewal. Recent data shows that miRNA regulates this small population of stem cells. In the present review, we explained different characteristics of cancer stem cells as well as miRNA regulation of self-renewal and differentiation in cancer stem cells. We also described the migration and tumor formation. Finally, we described the different miRNAs that regulate various types of cancer stem cells, such as prostate cancer stem cells, head and neck cancer stem cells, breast cancer stem cells, colorectal cancer stem cells, lung cancer stem cells, gastric cancer stem cells, pancreatic cancer stem cells, etc. Extensive research is needed in order to employ miRNA-based therapeutics to control cancer stem cell population in various cancers in the future.

What is a stem cell?

PubMed

Slack, Jonathan M W

2018-05-15

The historical roots of the stem cell concept are traced with respect to its usage in embryology and in hematology. The modern consensus definition of stem cells, comprising both pluripotent stem cells in culture and tissue-specific stem cells in vivo, is explained and explored. Methods for identifying stem cells are discussed with respect to cell surface markers, telomerase, label retention and transplantability, and properties of the stem cell niche are explored. The CreER method for identifying stem cells in vivo is explained, as is evidence in favor of a stochastic rather than an obligate asymmetric form of cell division. In conclusion, it is found that stem cells do not possess any unique and specific molecular markers; and stem cell behavior depends on the environment of the cell as well as the stem cell's intrinsic qualities. Furthermore, the stochastic mode of division implies that stem cell behavior is a property of a cell population not of an individual cell. In this sense, stem cells do not exist in isolation but only as a part of multicellular system. This article is categorized under: Adult Stem Cells, Tissue Renewal, and Regeneration > Tissue Stem Cells and Niches Adult Stem Cells, Tissue Renewal, and Regeneration > Methods and Principles Adult Stem Cells, Tissue Renewal, and Regeneration > Environmental Control of Stem Cells. © 2018 Wiley Periodicals, Inc.

Management of recurrent inflammatory choroidal neovascular membrane secondary to Vogt-Koyanagi-Harada syndrome, using combined intravitreal injection of bevacizumab and triamcinolone acetate.

PubMed

Pai, Sivakami A; Hebri, Sudhira P; Lootah, Afra M

2012-01-01

The purpose of this report is to evaluate the efficacy and safety of combined intravitreal injection of bevacizumab and intravitreal triamcinolone acetonide (IVTA) for recurrent inflammatory choroidal neovascular membrane (CNVM). It was a prospective interventional study of a young female, who was a known case of Vogt-Koyanagi-Harada syndrome. She presented with an inflammatory choroidal neovascualar membrane and signs of panuveitis in the right eye. She underwent a complete ophthalmic examination. She was given intravitreal injection of bevacizumab and IVTA at different sites. There was complete regression of CNVM and ocular inflammation within a week. After six months, she had recurrence of CNVM in the same eye, which was treated similarly. There was a complete resolution of CNVM and ocular inflammation after the combination therapy and systemic steroids, until one year of follow-up. No serious systemic or ocular adverse events were noted. Combination therapy appears to be an effective and safe method in the management of recurrent inflammatory CNVM.

Ranibizumab versus dexamethasone implant for central retinal vein occlusion: the RANIDEX study.

PubMed

Chatziralli, Irini; Theodossiadis, George; Kabanarou, Stamatina A; Parikakis, Efstratios; Xirou, Tina; Mitropoulos, Panagiotis; Theodossiadis, Panagiotis

2017-10-01

To compare intravitreal ranibizumab and dexamethasone implant in patients with macular edema (ME) secondary to central retinal vein occlusion (CRVO). Participants were 42 treatment naive patients with ME due to CRVO, who received either intravitreal 0.5 mg ranibizumab (n = 25) or intravitreal 0.7 mg dexamethasone implant (n = 17). The main outcomes included the mean change in best corrected visual acuity (BCVA) and central subfield thickness (CST) at month 12 compared to baseline in the two groups. At month 12, there was no statistically significant difference in BCVA and CST change between the two groups. However, there was recurrence in ME at month 5 in the dexamethasone group. Both ranibizumab and dexamethasone implant were found to be safe and effective at the 12-month follow-up in patients with ME secondary to CRVO. Since there was a recurrence in ME at month 5 in the dexamethasone group, we suggested that intravitreal injection of dexamethasone implant should be potentially administered sooner than 6 months.

[Systemic safety following intravitreal injections of anti-VEGF].

PubMed

Baillif, S; Levy, B; Girmens, J-F; Dumas, S; Tadayoni, R

2018-03-01

The goal of this manuscript is to assess data suggesting that intravitreal injection of anti-vascular endothelial growth factors (anti-VEGFs) could result in systemic adverse events (AEs). The class-specific systemic AEs should be similar to those encountered in cancer trials. The most frequent AE observed in oncology, hypertension and proteinuria, should thus be the most common expected in ophthalmology, but their severity should be lower because of the much lower doses of anti-VEGFs administered intravitreally. Such AEs have not been frequently reported in ophthalmology trials. In addition, pharmacokinetic and pharmacodynamic data describing systemic diffusion of anti-VEGFs should be interpreted with caution because of significant inconsistencies reported. Thus, safety data reported in ophthalmology trials and pharmacokinetic/pharmacodynamic data provide robust evidence that systemic events after intravitreal injection are very unlikely. Additional studies are needed to explore this issue further, as much remains to be understood about local and systemic side effects of anti-VEGFs. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Determination of the toxicity of intravitreal minocycline in rabbit eyes.

PubMed

Falavarjani, Khalil Ghasemi; Pourhabibi, Arash; Aghdam, Kaveh Abri; Hosseini, Seyed Bagher; Modarres, Mehdi; Pazouki, Abdolreza; Khanamiri, Hossein Nazari

2016-09-01

To evaluate the retinal toxicity of intravitreal minocycline in rabbit eyes. Intravitreal injection of minocycline with concentrations of 1000, 500, 250, 125 and 62.5 μg in 0.1 ml was performed in 10 New Zealand albino rabbits. Each concentration was injected into two rabbit eyes. For each dose, normal saline was injected in one contralateral eye and the other fellow eye remained non-injected. Electrophysiologic testing was performed before and 4 weeks after injections. The eyes were enucleated 4 weeks after injections and examined using light microscopy. The clinical examination was unremarkable after injections. Electroretinography recordings were significantly affected at all doses in at least one of the a- or b-waves of photopic or scotopic responses. Histopathologic examination revealed marked atrophy and loss of integrity in all retinal layers in all minocycline injected eyes. Contralateral eyes were normal. In our study, intravitreal minocycline was toxic to the retina in albino rabbits even at a concentration of 62.5 µg/0.1 ml.

Ocular biodistribution of bevasiranib following a single intravitreal injection to rabbit eyes

PubMed Central

Dejneka, Nadine S.; Wan, Shanhong; Bond, Ottrina S.; Kornbrust, Douglas J.

2008-01-01

Purpose The primary objective of these investigations was to determine the ocular biodistribution of bevasiranib, a small interfering RNA (siRNA) targeting vascular endothelial growth factor A (VEGF-A), following a single intravitreal injection to rabbit eyes. Methods A tissue distribution and pharmacokinetic study was conducted with 3H-bevasiranib prepared in balanced-salt solution (BSS). Single doses of either 0.5 mg/eye or 2.0 mg/eye of 3H-bevasiranib were given by intravitreal injection to Dutch-Belted rabbits (both eyes were treated). Subgroups of rabbits were serially-sacrificed at various times up to 7 days following dosing for collection of tissue samples. The right eye of each rabbit was collected whole, and the left eye was dissected to isolate five ocular tissues. All samples were analyzed by liquid scintillation counting to determine the concentrations of bevasiranib equivalents. An ocular disposition study was also performed with non-radiolabeled bevasiranib, which was administered to Dutch-Belted rabbit eyes via intravitreal injection at a dose of 2.0 mg/eye. Twenty-four hours post-dose, the eyes were enucleated and dissected into eight individual ocular structures that were analyzed for intact bevasiranib using a locked nuleic acid (LNA) noncompetitive hybridization-ligation enzyme-linked immunosorbent assay. Results Following intravitreal injection of 0.5 mg or 2.0 mg radiolabeled bevasiranib to Dutch-Belted rabbits, bevasiranib was detected in the vitreous, iris, retina, retinal pigment epithelium (RPE), and sclera (+choroid). As expected, the highest concentrations were found in the vitreous, and vitreous levels steadily decreased over time, while concentrations of radioactivity in the other ocular tissues increased to maximum values between 24 h and 72 h after dosing. Of these tissues, the highest concentration of radioactivity was detected in the retina. The LNA assay further confirmed the presence of intact bevasiranib in these tissues 24 h following intravitreal injection of non-radiolabeled bevasiranib (2 mg/eye). Conclusions These studies demonstrate distribution of bevasiranib throughout the eye following intravitreal injection, including extensive uptake into the retina. PMID:18523657

Ocular silicon distribution and clearance following intravitreal injection of porous silicon microparticles.

PubMed

Nieto, Alejandra; Hou, Huiyuan; Sailor, Michael J; Freeman, William R; Cheng, Lingyun

2013-11-01

Porous silicon (pSi) microparticles have been investigated for intravitreal drug delivery and demonstrated good biocompatibility. With the appropriate surface chemistry, pSi can reside in vitreous for months or longer. However, ocular distribution and clearance pathway of its degradation product, silicic acid, are not well understood. In the current study, rabbit ocular tissue was collected at different time point following fresh pSi (day 1, 5, 9, 16, and 21) or oxidized pSi (day 3, 7, 14, 21, and 35) intravitreal injection. In addition, dual-probe simultaneous microdialysis of aqueous and vitreous humor was performed following a bolus intravitreal injection of 0.25 mL silicic acid (150 μg/mL) and six consecutive microdialysates were collected every 20 min. Silicon was quantified from the samples using inductively coupled plasma-optical emission spectroscopy. The study showed that following the intravitreal injection of oxidized pSi, free silicon was consistently higher in the aqueous than in the retina (8.1 ± 6.5 vs. 3.4 ± 3.9 μg/mL, p = 0.0031). The area under the concentration-time curve (AUC) of the retina was only about 24% that of the aqueous. The mean residence time was 16 days for aqueous, 13 days for vitreous, 6 days for retina, and 18 days for plasma. Similarly, following intravitreal fresh pSi, free silicon was also found higher in aqueous than in retina (7 ± 4.7 vs. 3.4 ± 4.1 μg/mL, p = 0.014). The AUC for the retina was about 50% of the AUC for the aqueous. The microdialysis revealed the terminal half-life of free silicon in the aqueous was 30 min and 92 min in the vitreous; the AUC for aqueous accounted for 38% of the AUC for vitreous. Our studies indicate that aqueous humor is a significant pathway for silicon egress from the eye following intravitreal injection of pSi crystals. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Intravitreal bevacizumab for choroidal neovascularization associated with Best's disease].

PubMed

Velazquez-Villoria, D; Macià Badia, C; Rigo Quera, J; Velez-Escola, L; Arcos-Algaba, G; Martínez-Castillo, V; García-Arumí, J

2014-10-01

A 27-year old woman presented with loss of vision in the right eye (20/200). Ophthalmoscopic examination showed intrarretinal hemorrhage in the macular region with neurosensory detachment in the right eye, and viteliform deposit on the left eye. Fluorescein angiography and the electrooculogram confirmed the diagnosis of choroidal neovascularization associated with Best's disease. Four weeks after a single bevacizumab intravitreal injection, visual acuity was restored (20/25) and remained stable after a 12 month follow-up. Intravitreal bevacizumab appears to be an effective treatment for choroidal neovascularization associated to Best's disease. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

Outcome of cytomegalovirus retinitis in immunocompromised patients without Human Immunodeficiency Virus treated with intravitreal ganciclovir injection.

PubMed

Agarwal, Aniruddha; Kumari, Neha; Trehan, Amita; Khadwal, Alka; Dogra, Mangat R; Gupta, Vishali; Sharma, Aman; Gupta, Amod; Singh, Ramandeep

2014-09-01

To study the outcomes of treatment with intravitreal ganciclovir injection for cytomegalovirus (CMV) retinitis in patients without Human Immunodeficiency Virus (HIV) infection. In this retrospective cohort study, demographic and clinical characteristics of patients with CMV retinitis without HIV were noted. Patients received intravitreal ganciclovir injection (2 mg/0.1 ml) alone until quiescence. The outcome measures were time taken for the lesions to heal, number of injections, change in best-corrected visual acuity (BCVA), recurrence of retinitis, occurrence of immune recovery uveitis (IRU) or injection-related complications and retinal detachment (RD). 18 eyes of ten patients (six males) with mean age of 33.7 years from June 2004 to March 2013 were included. Thirteen eyes with active lesions (mean BCVA of 0.51 ± 0.41) received 5.54 ± 3.36 intravitreal ganciclovir injections with complete healing within 1.81 ± 1.25 months. The final BCVA was 0.43 ± 0.52. IRU was observed in six eyes (33.33%) and RD developed in one eye. One eye had recurrence 1 month after stopping ganciclovir injections. The rest of the patients had recurrence-free follow-up at 9.46 ± 12.42 months. Non-HIV patients with CMV retinitis can be successfully treated with intravitreal ganciclovir injection alone, avoiding the systemic side effects of systemic anti-CMV therapy.

Elimination of Topical Antibiotics for Intravitreous Injections and the Importance of Using Povidone-Iodine: Update From the Diabetic Retinopathy Clinical Research Network.

PubMed

Bhavsar, Abdhish R; Glassman, Adam R; Stockdale, Cynthia R; Jampol, Lee M

2016-10-01

This report provides updated endophthalmitis rates for eyes receiving intravitreous injections with and without povidone-iodine and rates with and without topical antibiotics from Diabetic Retinopathy Clinical Research Network clinical trials. Among 8 Diabetic Retinopathy Clinical Research Network clinical trials conducted from 2006 to 2015, 28 786 intravitreous injections were administered (3123 eyes), and 20 617 of those (2264 eyes) were administered between 2012 and 2015. Eleven cases of endophthalmitis occurred; 4 occurred between 2012 and 2015. Thirteen injections in 3 eyes from 2 participants were administered without povidone-iodine; both participants developed endophthalmitis in 1 eye. Of the remaining 28 773 injections (3120 eyes) performed with povidone-iodine, 9 cases of endophthalmitis occurred: 6 cases (0.05% of 11 565 injections) in eyes receiving topical antibiotics and 3 cases (0.02% of 17 208 injections) in eyes not receiving topical antibiotics (P = .17). While only a small number of eyes did not receive povidone-iodine just prior to an intravitreous injection, this report provides further evidence regarding the risk of endophthalmitis when povidone-iodine is not used before intravitreous injections. Exclusion of topical antibiotics was not associated with a higher risk of endophthalmitis. Continued use of povidone-iodine and consideration to eliminate topical antibiotics from injection procedures seems warranted.

Poly(ortho ester) nanoparticles targeted for chronic intraocular diseases: ocular safety and localization after intravitreal injection.

PubMed

Li, Huiling; Palamoor, Mallika; Jablonski, Monica M

2016-10-01

Treatment of posterior eye diseases is more challenging than the anterior segment ailments due to a series of anatomical barriers and physiological constraints confronted by drug delivery to the back of the eye. In recent years, concerted efforts in drug delivery have been made to prolong the residence time of drugs injected in the vitreous humor of the eye. Our previous studies demonstrated that poly(ortho ester) (POE) nanoparticles were biodegradable/biocompatible and were capable of long-term sustained release. The objective of the present study was to investigate the safety and localization of POE nanoparticles in New Zealand white rabbits and C57BL/6 mice after intravitreal administration for the treatment of chronic posterior ocular diseases. Two concentration levels of POE nanoparticles solution were chosen for intravitreal injection: 1.5 mg/ml and 10 mg/ml. Our results demonstrate that POE nanoparticles were distributed throughout the vitreous cavity by optical coherence tomography (OCT) examination 14 days post-intravitreal injection. Intraocular pressure was not changed from baseline. Inflammatory or adverse effects were undetectable by slit lamp biomicroscopy. Furthermore, we demonstrate that POE nanoparticles have negligible toxicity assessed at the cellular level evidenced by a lack of glia activation or apoptosis estimation after intravitreal injection. Collectively, POE nanoparticles are a novel and nontoxic as an ocular drug delivery system for the treatment of posterior ocular diseases.

Effects of Repeated Intravitreal Aflibercept Injection on the Corneal Endothelium in Patients With Age-Related Macular Degeneration: Outcomes From the RE-VIEW Study.

PubMed

Lass, Jonathan H; Benetz, Beth Ann; Menegay, Harry J; Tsipis, Constantinos P; Cook, Jane Caty; Boyer, David S; Singer, Michael; Erickson, Kristine; Saroj, Namrata; Vitti, Robert; Chu, Karen W; Moini, Hadi; Soo, Yuhwen; Cheng, Yenchieh

2018-05-01

The effects of repeated intravitreal aflibercept injection (IAI) on the corneal endothelium were studied in patients with unilateral neovascular age-related macular degeneration. RE-VIEW was a phase 4, open-label, single-arm, multicenter study. Patients received IAI every 8 weeks after 3 monthly doses. Slit-lamp biomicroscopy was performed at all study visits. The central corneal endothelial health was evaluated by specular microscopy in the treated versus untreated fellow eyes at baseline and weeks 24 and 52. No slit-lamp abnormalities were noted in 154 enrolled patients (eyes). Baseline versus 52-week mean (±SD) endothelial morphometric values (n = 118) for the treated versus untreated fellow eyes were respectively as follows: endothelial cell density was 2410 ± 364 versus 2388 ± 384 cells/mm at baseline and remained unchanged at 2401 ± 353 versus 2376 ± 364 cells/mm at 52 weeks (P = 0.87); the coefficient of variation was 33.5 ± 4.4% versus 34.0 ± 5.0% at baseline and remained unchanged at 34.2 ± 4.7% versus 34.1 ± 4.9% at 52 weeks (P = 0.18); the percentage of hexagonal cells was 59.5 ± 5.8% versus 59.6 ± 6.4% at baseline and remained unchanged at 59.5 ± 6.0% versus 59.5 ± 5.8% at 52 weeks (P = 0.96). Repeated IAI for 52 weeks had no apparent corneal endothelial toxicity noted on specular microscopy in patients treated for neovascular age-related macular degeneration.

Differential marker expression by cultures rich in mesenchymal stem cells

PubMed Central

2013-01-01

Background Mesenchymal stem cells have properties that make them amenable to therapeutic use. However, the acceptance of mesenchymal stem cells in clinical practice requires standardized techniques for their specific isolation. To date, there are no conclusive marker (s) for the exclusive isolation of mesenchymal stem cells. Our aim was to identify markers differentially expressed between mesenchymal stem cell and non-stem cell mesenchymal cell cultures. We compared and contrasted the phenotype of tissue cultures in which mesenchymal stem cells are rich and rare. By initially assessing mesenchymal stem cell differentiation, we established that bone marrow and breast adipose cultures are rich in mesenchymal stem cells while, in our hands, foreskin fibroblast and olfactory tissue cultures contain rare mesenchymal stem cells. In particular, olfactory tissue cells represent non-stem cell mesenchymal cells. Subsequently, the phenotype of the tissue cultures were thoroughly assessed using immuno-fluorescence, flow-cytometry, proteomics, antibody arrays and qPCR. Results Our analysis revealed that all tissue cultures, regardless of differentiation potential, demonstrated remarkably similar phenotypes. Importantly, it was also observed that common mesenchymal stem cell markers, and fibroblast-associated markers, do not discriminate between mesenchymal stem cell and non-stem cell mesenchymal cell cultures. Examination and comparison of the phenotypes of mesenchymal stem cell and non-stem cell mesenchymal cell cultures revealed three differentially expressed markers – CD24, CD108 and CD40. Conclusion We indicate the importance of establishing differential marker expression between mesenchymal stem cells and non-stem cell mesenchymal cells in order to determine stem cell specific markers. PMID:24304471

Learn About Stem Cells

MedlinePlus

... Handbook Stem Cell Glossary Search Toggle Nav Stem Cell Basics Stem cells are the foundation from which ... Home > Learn About Stem Cells > Stem Cell Basics Cells in the human body The human body comprises ...

Erythroid differentiation of human induced pluripotent stem cells is independent of donor cell type of origin.

PubMed

Dorn, Isabel; Klich, Katharina; Arauzo-Bravo, Marcos J; Radstaak, Martina; Santourlidis, Simeon; Ghanjati, Foued; Radke, Teja F; Psathaki, Olympia E; Hargus, Gunnar; Kramer, Jan; Einhaus, Martin; Kim, Jeong Beom; Kögler, Gesine; Wernet, Peter; Schöler, Hans R; Schlenke, Peter; Zaehres, Holm

2015-01-01

Epigenetic memory in induced pluripotent stem cells, which is related to the somatic cell type of origin of the stem cells, might lead to variations in the differentiation capacities of the pluripotent stem cells. In this context, induced pluripotent stem cells from human CD34(+) hematopoietic stem cells might be more suitable for hematopoietic differentiation than the commonly used fibroblast-derived induced pluripotent stem cells. To investigate the influence of an epigenetic memory on the ex vivo expansion of induced pluripotent stem cells into erythroid cells, we compared induced pluripotent stem cells from human neural stem cells and human cord blood-derived CD34(+) hematopoietic stem cells and evaluated their potential for differentiation into hematopoietic progenitor and mature red blood cells. Although genome-wide DNA methylation profiling at all promoter regions demonstrates that the epigenetic memory of induced pluripotent stem cells is influenced by the somatic cell type of origin of the stem cells, we found a similar hematopoietic induction potential and erythroid differentiation pattern of induced pluripotent stem cells of different somatic cell origin. All human induced pluripotent stem cell lines showed terminal maturation into normoblasts and enucleated reticulocytes, producing predominantly fetal hemoglobin. Differences were only observed in the growth rate of erythroid cells, which was slightly higher in the induced pluripotent stem cells derived from CD34(+) hematopoietic stem cells. More detailed methylation analysis of the hematopoietic and erythroid promoters identified similar CpG methylation levels in the induced pluripotent stem cell lines derived from CD34(+) cells and those derived from neural stem cells, which confirms their comparable erythroid differentiation potential. Copyright© Ferrata Storti Foundation.

[Progress in stem cells and regenerative medicine].

PubMed

Wang, Libin; Zhu, He; Hao, Jie; Zhou, Qi

2015-06-01

Stem cells have the ability to differentiate into all types of cells in the body and therefore have great application potential in regenerative medicine, in vitro disease modelling and drug screening. In recent years, stem cell technology has made great progress, and induced pluripotent stem cell technology revolutionizes the whole stem cell field. At the same time, stem cell research in our country has also achieved great progress and becomes an indispensable power in the worldwide stem cell research field. This review mainly focuses on the research progress in stem cells and regenerative medicine in our country since the advent of induced pluripotent stem cell technology, including induced pluripotent stem cells, transdifferentiation, haploid stem cells, and new gene editing tools.

Application of Graphene Based Nanotechnology in Stem Cells Research.

PubMed

Hu, Shanshan; Zeng, Yongxiang; Yang, Shuying; Qin, Han; Cai, He; Wang, Jian

2015-09-01

The past several years have witnessed significant advances in stem cell therapy, tissue engineering and regenerative medicine. Graphene, with its unique properties such as high electrical conductivity, elasticity and good molecule absorption, have potential for creating the next generation of biomaterials. This review summarizes the interrelationship between graphene and stem cells. The analysis of graphene when applied on mesenchymal stem cells, neural stem cells, induced pluripotent stem cells, embryonic stem cells, periodontal ligament stem cells, human adipose-derived stem cells and cancer stem cells, and how graphene influences cell behavior and differentiation are discussed in details.

A revisionist history of adult marrow stem cell biology or 'they forgot about the discard'.

PubMed

Quesenberry, P; Goldberg, L

2017-08-01

The adult marrow hematopoietic stem cell biology has largely been based on studies of highly purified stem cells. This is unfortunate because during the stem cell purification the great bulk of stem cells are discarded. These cells are actively proliferating. The final purified stem cell is dormant and not representative of the whole stem cell compartment. Thus, a large number of studies on the cellular characteristics, regulators and molecular details of stem cells have been carried on out of non-represented cells. Niche studies have largely pursued using these purified stem cells and these are largely un-interpretable. Other considerations include the distinction between baseline and transplant stem cells and the modulation of stem cell phenotype by extracellular vesicles, to cite a non-inclusive list. Work needs to proceed on characterizing the true stem cell population.

Anti-VEGF aptamer (pegaptanib) therapy for ocular vascular diseases.

PubMed

Ng, Eugene W M; Adamis, Anthony P

2006-10-01

Vascular endothelial growth factor (VEGF) is a central regulator of both physiological and pathological angiogenesis. Pegaptanib, a 28-nucleotide RNA aptamer specific for the VEGF(165) isoform, binds to it in the extracellular space, leaving other isoforms unaffected, and inhibits such key VEGF actions as promotion of endothelial cell proliferation and survival, and vascular permeability. Pegaptanib already has been examined as a treatment for two diseases associated with ocular neovascularization, age-related macular degeneration (AMD) and diabetic macular edema (DME). Preclinical studies have shown that VEGF(165) alone mediates pathological ocular neovascularization and that its inactivation by pegaptanib inhibits the choroidal neovascularization observed in patients with neovascular AMD. In contrast, physiological vascularization, which is supported by the VEGF(121) isoform, is unaffected by this inactivation of VEGF(165). In addition, animal model studies have shown that intravitreous injection of pegaptanib can inhibit the breakdown of the blood-retinal barrier characteristic of diabetes and even can reverse this damage to some degree. These preclinical findings formed the basis for randomized controlled trials examining the efficacy of pegaptanib as a therapy for AMD and DME. The VEGF Inhibition Study in Ocular Neovascularization (VISION) trial comprising two replicate, pivotal phase 3 studies, demonstrated that intravitreous injection of pegaptanib resulted in significant clinical benefit, compared with sham injection, for all prespecified clinical end points, irrespective of patient demographics or angiographic subtype, and led to pegaptanib's approval as a treatment for AMD. A phase 2 trial has provided support for the efficacy of intravitreous pegaptanib in the treatment of DME.

Apatinib, an Inhibitor of Vascular Endothelial Growth Factor Receptor 2, Suppresses Pathologic Ocular Neovascularization in Mice.

PubMed

Kim, Koung Li; Suh, Wonhee

2017-07-01

Vascular endothelial growth factor (VEGF) signaling via VEGF receptor 2 (VEGFR2) plays a crucial role in pathologic ocular neovascularization. In this study, we investigated the antiangiogenic effect of apatinib, a pharmacologic inhibitor of VEGFR2 tyrosine kinase, against oxygen-induced retinopathy (OIR) and laser-induced choroidal neovascularization (CNV) in mice. Western blotting and in vitro angiogenesis assays were performed using human retinal microvascular endothelial cells (HRMECs). OIR was induced in neonatal mice by exposure to 75% oxygen from postnatal day (P) 7 to P12 and to room air from P12 to P17. Experimental CNV was induced in mice using laser photocoagulation. Apatinib was intravitreally and orally administered to mice. Neovascularization and phosphorylation of VEGFR2 were evaluated by immunofluorescence staining. Apatinib inhibited VEGF-mediated activation of VEGFR2 signaling and substantially reduced VEGF-induced proliferation, migration, and cord formation in HRMECs. A single intravitreal injection of apatinib significantly attenuated retinal or choroidal neovascularization in mice with OIR or laser injury-induced CNV, respectively. Retinal or choroidal tissues of the eyes treated with apatinib exhibited substantially lower phosphorylation of VEGFR2 than those of controls injected with vehicle. Intravitreal injection of apatinib did not cause noticeable ocular toxicity. Moreover, oral administration of apatinib significantly reduced laser-induced CNV in mice. Our study demonstrates that apatinib inhibits pathologic ocular neovascularization in mice with OIR or laser-induced CNV. Apatinib may, therefore, be a promising drug for the prevention and treatment of ischemia-induced proliferative retinopathy and neovascular age-related macular degeneration.

Perspectives on stem cell therapy for cardiac regeneration. Advances and challenges.

PubMed

Choi, Sung Hyun; Jung, Seok Yun; Kwon, Sang-Mo; Baek, Sang Hong

2012-01-01

Ischemic heart disease (IHD) accelerates cardiomyocyte loss, but the developing stem cell research could be useful for regenerating a variety of tissue cells, including cardiomyocytes. Diverse sources of stem cells for IHD have been reported, including embryonic stem cells, induced pluripotent stem cells, skeletal myoblasts, bone marrow-derived stem cells, mesenchymal stem cells, and cardiac stem cells. However, stem cells have unique advantages and disadvantages for cardiac tissue regeneration, which are important considerations in determining the specific cells for improving cell survival and long-term engraftment after transplantation. Additionally, the dosage and administration method of stem cells need to be standardized to increase stability and efficacy for clinical applications. Accordingly, this review presents a summary of the stem cell therapies that have been studied for cardiac regeneration thus far, and discusses the direction of future cardiac regeneration research for stem cells.

Stem Cells

MedlinePlus

Stem cells are cells with the potential to develop into many different types of cells in the body. They serve as a repair ... body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

The Role of Integrin α6 (CD49f) in Stem Cells: More than a Conserved Biomarker.

PubMed

Krebsbach, Paul H; Villa-Diaz, Luis G

2017-08-01

Stem cells have the capacity for self-renewal and differentiation into specialized cells that form and repopulated all tissues and organs, from conception to adult life. Depending on their capacity for differentiation, stem cells are classified as totipotent (ie, zygote), pluripotent (ie, embryonic stem cells), multipotent (ie, neuronal stem cells, hematopoietic stem cells, epithelial stem cells, etc.), and unipotent (ie, spermatogonial stem cells). Adult or tissue-specific stem cells reside in specific niches located in, or nearby, their organ or tissue of origin. There, they have microenvironmental support to remain quiescent, to proliferate as undifferentiated cells (self-renewal), and to differentiate into progenitors or terminally differentiated cells that migrate from the niche to perform specialized functions. The presence of proteins at the cell surface is often used to identify, classify, and isolate stem cells. Among the diverse groups of cell surface proteins used for these purposes, integrin α6, also known as CD49f, may be the only biomarker commonly found in more than 30 different populations of stem cells, including some cancer stem cells. This broad expression among stem cell populations indicates that integrin α6 may play an important and conserved role in stem cell biology, which is reaffirmed by recent demonstrations of its role maintaining self-renewal of pluripotent stem cells and breast and glioblastoma cancer stem cells. Therefore, this review intends to highlight and synthesize new findings on the importance of integrin α6 in stem cell biology.

Immunogenicity testing of therapeutic antibodies in ocular fluids after intravitreal injection.

PubMed

Wessels, Uwe; Zadak, Markus; Reiser, Astrid; Brockhaus, Janis; Ritter, Mirko; Abdolzade-Bavil, Afsaneh; Heinrich, Julia; Stubenrauch, Kay

2018-04-11

High drug concentrations in ocular fluids after intravitreal administration preclude the use of drug-sensitive immunoassays. A drug-tolerant immunoassay is therefore desirable for immunogenicity testing in ophthalmology. Immune complex (IC) antidrug antibody (ADA) assays were established for two species. The assays were compared with the bridging assay in ocular and plasma samples from two preclinical studies. The IC assays showed high drug tolerance, which enabled a reliable ADA detection in ocular fluids after intravitreal administration. The IC assays were superior to the bridging assay in the analysis of ocular fluids with high drug concentrations. The IC assay allows a reliable ADA detection in matrices with high drug concentrations, such as ocular fluids.

Resolution of macular edema in Coats' disease with intravitreal bevacizumab

PubMed Central

Entezari, Morteza; Ramezani, Alireza; Safavizadeh, Ladan; Bassirnia, Nader

2010-01-01

A 13-year-old boy was referred because of visual deterioration in his right eye. The visual acuity was two meters of counting fingers. Indirect ophthalmoscopy and biomicroscopy revealed exudative macular edema as well as tumor-like telangiectatic vessels and exudation in temporal periphery. With diagnosis of Coats' disease (stage II) confirmed by fluorescein angiography, three intravitreal injections of bevacizumab were performed at 6-week intervals. One year after the last injection, there was a significant resolution of macular edema as well as visual acuity improvement to 20/20. This is the first case report in which a distinct improvement in macular edema was observed with intravitreal bevacizumab in Coats' disease. PMID:20029156

[Subretinal neovascular membrane in angioid streaks treated with intravitreal bevacizumab].

PubMed

García-López, A; González-Castaño, C

2014-05-01

Angioid streaks are breaks in Bruch's membrane that may be associated, among others, with pseudoxanthoma elasticum. Its most common complication is the development of subretinal neovascular membranes (SRNVM) and the decreased vision this entails. A 28 year old woman with angioid streaks and SRNVM in the left eye, who received 3 injections of intravitreal bevacizumab, with rapid improvement in vision and stability during 11 months follow up. The finding of angioid streaks led to the diagnosis of pseudoxanthoma elasticum. Intravitreal bevacizumab should be considered as an effective treatment option for choroidal neovascularization associated with angioid streaks. Copyright © 2012 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

Drosophila's contribution to stem cell research.

PubMed

Singh, Gyanesh

2015-01-01

The discovery of Drosophila stem cells with striking similarities to mammalian stem cells has brought new hope for stem cell research. Recent developments in Drosophila stem cell research is bringing wider opportunities for contemporary stem cell biologists. In this regard, Drosophila germ cells are becoming a popular model of stem cell research. In several cases, genes that controlled Drosophila stem cells were later discovered to have functional homologs in mammalian stem cells. Like mammals, Drosophila germline stem cells (GSCs) are controlled by both intrinsic as well as external signals. Inside the Drosophila testes, germline and somatic stem cells form a cluster of cells (the hub). Hub cells depend on JAK-STAT signaling, and, in absence of this signal, they do not self-renew. In Drosophila, significant changes occur within the stem cell niche that contributes to a decline in stem cell number over time. In case of aging Drosophila, somatic niche cells show reduced DE-cadherin and unpaired (Upd) proteins. Unpaired proteins are known to directly decrease stem cell number within the niches, and, overexpression of upd within niche cells restored GSCs in older males also . Stem cells in the midgut of Drosophila are also very promising. Reduced Notch signaling was found to increase the number of midgut progenitor cells. On the other hand, activation of the Notch pathway decreased proliferation of these cells. Further research in this area should lead to the discovery of additional factors that regulate stem and progenitor cells in Drosophila.

Drosophila's contribution to stem cell research

PubMed Central

Singh, Gyanesh

2016-01-01

The discovery of Drosophila stem cells with striking similarities to mammalian stem cells has brought new hope for stem cell research. Recent developments in Drosophila stem cell research is bringing wider opportunities for contemporary stem cell biologists. In this regard, Drosophila germ cells are becoming a popular model of stem cell research. In several cases, genes that controlled Drosophila stem cells were later discovered to have functional homologs in mammalian stem cells. Like mammals, Drosophila germline stem cells (GSCs) are controlled by both intrinsic as well as external signals. Inside the Drosophila testes, germline and somatic stem cells form a cluster of cells (the hub). Hub cells depend on JAK-STAT signaling, and, in absence of this signal, they do not self-renew. In Drosophila, significant changes occur within the stem cell niche that contributes to a decline in stem cell number over time. In case of aging Drosophila, somatic niche cells show reduced DE-cadherin and unpaired (Upd) proteins. Unpaired proteins are known to directly decrease stem cell number within the niches, and, overexpression of upd within niche cells restored GSCs in older males also . Stem cells in the midgut of Drosophila are also very promising. Reduced Notch signaling was found to increase the number of midgut progenitor cells. On the other hand, activation of the Notch pathway decreased proliferation of these cells. Further research in this area should lead to the discovery of additional factors that regulate stem and progenitor cells in Drosophila. PMID:26180635

Current overview on dental stem cells applications in regenerative dentistry.

PubMed

Bansal, Ramta; Jain, Aditya

2015-01-01

Teeth are the most natural, noninvasive source of stem cells. Dental stem cells, which are easy, convenient, and affordable to collect, hold promise for a range of very potential therapeutic applications. We have reviewed the ever-growing literature on dental stem cells archived in Medline using the following key words: Regenerative dentistry, dental stem cells, dental stem cells banking, and stem cells from human exfoliated deciduous teeth. Relevant articles covering topics related to dental stem cells were shortlisted and the facts are compiled. The objective of this review article is to discuss the history of stem cells, different stem cells relevant for dentistry, their isolation approaches, collection, and preservation of dental stem cells along with the current status of dental and medical applications.

The longest telomeres: a general signature of adult stem cell compartments

PubMed Central

Flores, Ignacio; Canela, Andres; Vera, Elsa; Tejera, Agueda; Cotsarelis, George; Blasco, María A.

2008-01-01

Identification of adult stem cells and their location (niches) is of great relevance for regenerative medicine. However, stem cell niches are still poorly defined in most adult tissues. Here, we show that the longest telomeres are a general feature of adult stem cell compartments. Using confocal telomere quantitative fluorescence in situ hybridization (telomapping), we find gradients of telomere length within tissues, with the longest telomeres mapping to the known stem cell compartments. In mouse hair follicles, we show that cells with the longest telomeres map to the known stem cell compartments, colocalize with stem cell markers, and behave as stem cells upon treatment with mitogenic stimuli. Using K15-EGFP reporter mice, which mark hair follicle stem cells, we show that GFP-positive cells have the longest telomeres. The stem cell compartments in small intestine, testis, cornea, and brain of the mouse are also enriched in cells with the longest telomeres. This constitutes the description of a novel general property of adult stem cell compartments. Finally, we make the novel finding that telomeres shorten with age in different mouse stem cell compartments, which parallels a decline in stem cell functionality, suggesting that telomere loss may contribute to stem cell dysfunction with age. PMID:18283121

[Managment of subretinal heamorrhages within the macular area using intravitreal injections of recombined tissue plasminogen activator, sulphur hexafluoride and ranihizumab--preliminary report].

PubMed

Miniewicz, Joanna; Kubicka-Trząska, Agnieszka; Karska-Basta, Izabella; Romanowska-Dixon, Boźena

2015-01-01

Submacular hemorrhages cause serious vision impairment. Patient observation, waiting for the spontaneous blood reabsorption and resolution of the haemorrhage leads to the severe damage to retinal tissue as a result of scar formation. The paper presents 7 cases of patients with submacular haemorrhages treated with intravitreal injections of recombined tissue plasminogen activator (rtPA) and sulphur hexafluoride (SFG). In 4 cases, the haemorrhage was secondary to AMD, in two cases to trauma, and it was idiopathic in one case. All patients were treated with intravitreal injections of rtPA and SF6 for thrombolysis and pneumatic displacement of haemorrhage outside macular structures. Ranibizumab was additionally administered to patients with age-related macular degeneration. Such treatment improved visual acuity in all patients, reducing the central retinal thickness as shown in follow-up optical coherence tomography. The presented treatment of submacular hemorrhages with intravitreal injections of rtPA and SF6 provided good results, but in order to develop a standard management algorithm for this disease, the analysis of larger patient sample is required.

Intravitreal steroids for the treatment of retinal diseases.

PubMed

Sarao, Valentina; Veritti, Daniele; Boscia, Francesco; Lanzetta, Paolo

2014-01-01

Diabetic macular edema (DME), pseudophakic cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO), and uveitis are ocular conditions related to severe visual impairment worldwide. Corticosteroids have been widely used in the treatment of these retinal diseases, due to their well-known antiangiogenic, antiedematous, and anti-inflammatory properties. Intravitreal steroids have emerged as novel and essential tools in the ophthalmologist's armamentarium, allowing for maximization of drug efficacy and limited risk of systemic side effects. Recent advances in ocular drug delivery methods led to the development of intraocular implants, which help to provide prolonged treatment with controlled drug release. Moreover, they may add some potential advantages over traditional intraocular injections by delivering certain rates of drug directly to the site of action, amplifying the drug's half-life, contributing in the minimization of peak plasma levels of the drug, and avoiding the side effects associated with repeated intravitreal injections. The purpose of this review is to provide an update on the use of intravitreal steroids as a treatment option for a variety of retinal diseases and to review the current literature considering their properties, safety, and adverse events.

Context clues: the importance of stem cell-material interactions

PubMed Central

Murphy, William L.

2014-01-01

Understanding the processes by which stem cells give rise to de novo tissues is an active focus of stem cell biology and bioengineering disciplines. Instructive morphogenic cues surrounding the stem cell during morphogenesis create what is referred to as the stem cell microenvironment. An emerging paradigm in stem cell bioengineering involves “biologically driven assembly,” in which stem cells are encouraged to largely define their own morphogenesis processes. However, even in the case of biologically driven assembly, stem cells do not act alone. The properties of the surrounding microenvironment can be critical regulators of cell fate. Stem cell-material interactions are among the most well-characterized microenvironmental effectors of stem cell fate, and they establish a signaling “context” that can define the mode of influence for morphogenic cues. Here we describe illustrative examples of cell-material interactions that occur during in vitro stem cell studies, with an emphasis on how cell-material interactions create instructive contexts for stem cell differentiation and morphogenesis. PMID:24369691

Cancer stem cells and differentiation therapy.

PubMed

Jin, Xiong; Jin, Xun; Kim, Hyunggee

2017-10-01

Cancer stem cells can generate tumors from only a small number of cells, whereas differentiated cancer cells cannot. The prominent feature of cancer stem cells is its ability to self-renew and differentiate into multiple types of cancer cells. Cancer stem cells have several distinct tumorigenic abilities, including stem cell signal transduction, tumorigenicity, metastasis, and resistance to anticancer drugs, which are regulated by genetic or epigenetic changes. Like normal adult stem cells involved in various developmental processes and tissue homeostasis, cancer stem cells maintain their self-renewal capacity by activating multiple stem cell signaling pathways and inhibiting differentiation signaling pathways during cancer initiation and progression. Recently, many studies have focused on targeting cancer stem cells to eradicate malignancies by regulating stem cell signaling pathways, and products of some of these strategies are in preclinical and clinical trials. In this review, we describe the crucial features of cancer stem cells related to tumor relapse and drug resistance, as well as the new therapeutic strategy to target cancer stem cells named "differentiation therapy."

Clinical trials for stem cell transplantation: when are they needed?

PubMed

Van Pham, Phuc

2016-04-27

In recent years, both stem cell research and the clinical application of these promising cells have increased rapidly. About 1000 clinical trials using stem cells have to date been performed globally. More importantly, more than 10 stem cell-based products have been approved in some countries. With the rapid growth of stem cell applications, some countries have used clinical trials as a tool to diminish the rate of clinical stem cell applications. However, the point at which stem cell clinical trials are essential remains unclear. This commentary discusses when stem cell clinical trials are essential for stem cell transplantation therapies.

Focal macular electroretinograms after intravitreal injections of bevacizumab for age-related macular degeneration.

PubMed

Iwata, Eiji; Ueno, Shinji; Ishikawa, Kohei; Ito, Yasuki; Uetani, Ruka; Piao, Chang-Hua; Kondo, Mineo; Terasaki, Hiroko

2012-06-28

To evaluate the changes in the best-corrected visual acuity (BCVA), macular thickness, and focal macular electroretinograms (FMERGs) after three intravitreal injections of bevacizumab for a choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD). The medical records of 18 eyes of 18 patients who had received three consecutive monthly intravitreal injections of bevacizumab were retrospectively studied. The BCVA, macular thickness determined by optical coherence tomography (OCT), and FMERGs were measured before the first injection, and 10 days after each of the intravitreal bevacizumab injections. The number of eyes with improvement in BCVA after the first injection was one (6%), after the second injection was four (22%), and after the third injection was five (28%). The number of eyes with reduction in macular thickness was 4 (33%), 8 (44%), and 10 (56%) after each of the three injections. The number of eyes with increase in b-wave amplitude of the FMERGs was 7 (38%), 6 (33%), and 10 (56%) after each of the three each injections. The mean macular thickness was significantly thinner after the first injection, and the mean BCVA was significantly improved after the second injection. The mean amplitude and implicit time of the b-wave of the FMERGs were significantly improved only after the third injection (P<0.05). All parameters improved but the best was after the third injection, indicating that three monthly intravitreous injections with bevacizumab may be an effective treatment regimen for AMD.

Transfer of single dose of intravitreal injection of ranibizumab and bevacizumab into milk of sheep

PubMed Central

Cakmak Argun, Tugba; Yalcin Tok, Ozlem; Tok, Levent; Yilmaz, Gulsen; Meric Yilmaz, Fatma; Gunes, Alime; Argun, Mehmet; Butuner, Osman

2017-01-01

AIM To investigate whether single-dose intravitreal injections of bevacizumab and ranibizumab transfer into milk. METHODS This study included lactating 12 sheep and a single 3-month old suckling lamb of each sheep. Two groups consisting of 6 sheep and their lambs were constituted; the ranibizumab group and the bevacizumab group before the administration of intravitreal injections, blood and milk samples were obtained from all sheep and, following the injections, blood and milk samples of all sheep and blood samples of all lambs were collected at regular time points. Serum and milk concentrations of bevacizumab and ranibizumab were measured using an enzyme-linked immunosorbent assay (ELISA) kit. The limit of determination was 0.9 ng/mL for bevacizumab and 0.62 ng/mL for ranibizumab. RESULTS At 6h after intravitreal injections, bevacizumab concentration was above the limit of determination in the blood of all sheep. At 3wk, when the study was terminated, bevacizumab concentrations were high in 4 sheep. Even though bevacizumab concentrations in milk showed fluctuations, the drug transferred into the milk of all sheep at detectable concentrations. Ranibizumab drug concentrations in the blood and milk of sheep and those in the blood of lambs were below the limit of determination by the ELISA kit. CONCLUSION This sheep model study demonstrate that intravitreal injection of ranibizumab, which did not transfer into the milk of sheep and suckling lambs, is safer than bevacizumab during lactation period. PMID:28730108

Incidence of Endophthalmitis after Intravitreal Bevacizumab using Aliquots Prepared On-site in 2 Operating Rooms in Kuwait

PubMed Central

Wani, Vivek B.; Al-Kandari, Jamal; Sabti, Khalid; Aljassar, Faisal; Qali, Hussain; Kumar, Niranjan; Uboweja, Anilkumar; Al-Sabah, Khalid; Diab, Fahad A.; Al-Rashidi, Saleh

2016-01-01

Purpose: To report the incidence of endophthalmitis after intravitreal injection of bevacizumab and the outcomes of treatment of endophthalmitis at two centers in Kuwait. Subjects and Methods: The aliquots of bevacizumab were prepared under aseptic precautions and administered in the operating theater on the same day at both centers. All patients received antibiotic drops after injection of bevacizumab. Data were collected on the number of cases that received intravitreal bevacizumab (IVB) and those that developed endophthalmitis were identified at the two centers. All cases of endophthalmitis received an intravitreal antibiotic injection and additional treatments as warranted. Data were collected on the outcomes of endophthalmitis treatment. Results: There were 5 cases of endophthalmitis among a total of 5429 injections (0.09%: Confidence interval: 0.084–0.1). The incidence was 3 cases among 4690 (0.06%) and 2 cases among 739 injections (0.027%) at each center, respectively (P = 0.08). Four cases of endophthalmitis were culture-positive and organisms isolated were, coagulase negative Staphylococcus in 2 cases, Staphylococcus lugdunensis and Streptococcus pneumoniae in 1 case each. The final visual acuity was better than pre-IVB in 3 cases, same as pre-IVB in 1 case and worse in 1 case with streptococcal infection. No eyes developed phthisis bulbi or required enucleation. Conclusions: The incidence of endophthalmitis after intravitreal injection of bevacizumab using aliquots prepared in the operating room is comparable to other studies. There were no clusters of endophthalmitis cases. PMID:26957841

Comparison between intravitreal bevacizumab and triamcinolone for macular edema secondary to branch retinal vein occlusion.

PubMed

Kim, Jin Young; Park, Sung Pyo

2009-12-01

To compare the effects of intravitreal bevacizumab to those of triamcinolone acetonide injection for the treatment of macular edema secondary to branch retinal vein occlusion. This retrospective study included 50 eyes of 50 patients who received a single injection of intravitreal bevacizumab (1.25 mg/0.05 mL, 22 eyes) or triamcinolone acetonide (4 mg/0.1 mL, 28 eyes) as the only treatment for macular edema secondary to branch retinal vein occlusion; all patients had a post-injection follow-up duration of >24 weeks. Best corrected visual acuity (BCVA), intraocular pressure (IOP), and central macular thickness (CMT) by optical coherence tomography were measured for up to 24 weeks after injection. BCVA was improved at 1, 4, 8,12 weeks post-injection in the bevacizumab group, and at 1, 4, 8 weeks post-injection in the triamcinolone group. No significant difference was found between the two groups except at 12 weeks. CMT decreased significantly within each group, and no significant difference between groups was found. In the bevacizumab group, no elevated IOP was observed, whereas IOP was significantly increased at 4, 8, and 12 weeks after triamcinolone injection; IOP was therefore significantly different between the two groups. Intravitreal bevacizumab is a comparatively simple treatment method that can effectively improve BCVA and reduce CMT without ocular and systemic complications. Consequently, intravitreal bevacizumab injections may be useful as both an alternative and primary treatment for macular edema secondary to branch retinal vein occlusion.

Survey of intravitreal injection techniques among retina specialists in Israel

PubMed Central

Segal, Ori; Segal-Trivitz, Yael; Nemet, Arie Y; Geffen, Noa; Nesher, Ronit; Mimouni, Michael

2016-01-01

Purpose The purpose of this study was to describe antivascular endothelial growth factor intravitreal injection techniques of retinal specialists in order to establish a cornerstone for future practice guidelines. Methods All members of the Israeli Retina Society were contacted by email to complete an anonymous, 19-question, Internet-based survey regarding their intravitreal injection techniques. Results Overall, 66% (52/79) completed the survey. Most (98%) do not instruct patients to discontinue anticoagulant therapy and 92% prescribe treatment for patients in the waiting room. Three quarters wear sterile gloves and prepare the patient in the supine position. A majority (71%) use sterile surgical draping. All respondents apply topical analgesics and a majority (69%) measure the distance from the limbus to the injection site. A minority (21%) displace the conjunctiva prior to injection. A majority of the survey participants use a 30-gauge needle and the most common quadrant for injection is superotemporal (33%). Less than half routinely assess postinjection optic nerve perfusion (44%). A majority (92%) apply prophylactic antibiotics immediately after the injection. Conclusion The majority of retina specialists perform intravitreal injections similarly. However, a relatively large minority performs this procedure differently. Due to the extremely low percentage of complications, it seems as though such differences do not increase the risk. However, more evidence-based medicine, a cornerstone for practice guidelines, is required in order to identify the intravitreal injection techniques that combine safety and efficacy while causing as little discomfort to the patients as possible. PMID:27366050

Stem cells - biological update and cell therapy progress

PubMed Central

GIRLOVANU, MIHAI; SUSMAN, SERGIU; SORITAU, OLGA; RUS-CIUCA, DAN; MELINCOVICI, CARMEN; CONSTANTIN, ANNE-MARIE; MIHU, CARMEN MIHAELA

2015-01-01

In recent years, the advances in stem cell research have suggested that the human body may have a higher plasticity than it was originally expected. Until now, four categories of stem cells were isolated and cultured in vivo: embryonic stem cells, fetal stem cells, adult stem cells and induced pluripotent stem cells (hiPSCs). Although multiple studies were published, several issues concerning the stem cells are still debated, such as: the molecular mechanisms of differentiation, the methods to prevent teratoma formation or the ethical and religious issues regarding especially the embryonic stem cell research. The direct differentiation of stem cells into specialized cells: cardiac myocytes, neural cells, pancreatic islets cells, may represent an option in treating incurable diseases such as: neurodegenerative diseases, type I diabetes, hematologic or cardiac diseases. Nevertheless, stem cell-based therapies, based on stem cell transplantation, remain mainly at the experimental stages and their major limitation is the development of teratoma and cancer after transplantation. The induced pluripotent stem cells (hiPSCs) represent a prime candidate for future cell therapy research because of their significant self-renewal and differentiation potential and the lack of ethical issues. This article presents an overview of the biological advances in the study of stem cells and the current progress made in the field of regenerative medicine. PMID:26609255

Diffuse chorioretinal atrophy after a single standard low- dose intravitreal melphalan injection in a child with retinoblastoma: a case report.

PubMed

Chao, An- Ning; Kao, Ling-Yuh; Liu, Laura; Wang, Nan-Kai

2016-03-15

Controlling retinoblastoma with seeding is challenging despite advances in treatment modalities. Intravitreal melphalan is an alternative to external beam radiation or enucleation for recurrent or refractory vitreous seeds. Significant ocular side effects following intravitreal melphalan injections are uncommon. Complications have been reported in eyes receiving higher concentrations of melphalan and repetitive injections. We report a case in which diffuse chorioretinal atrophy was developed at the injection site after a single, standard low-dose intravitreal melphalan injection. A 12-month-old female child without a family history of retinoblastoma presented with unilateral group C retinoblastoma in her right eye. A solitary tumour with retinal breaks on the tumour surface, and vitreous seeds overlying the tumour were observed at the 8 o'clock position of the retina. After two cycles of intra-arterial chemotherapy with melphalan, the main tumour displayed significant regression, but the vitreous seeds overlying the main tumour were still active. Because of the persistence of vitreous seeds and the inadequate response to intra-arterial melphalan treatment, intravitreal melphalan (8 μg in 0.05 mL) was injected using a 32-gauge needle 2.5 mm from the 5 o'clock position of the limbus, the meridian opposite to the vitreous seeds. After 1 month, the retina around the injection site demonstrated diffuse retinal pigment epithelium alterations with dense hard exudates. Although the main retinal mass, and vitreous seeds resolved, the hard exudates persisted for more than 2 years after the single low-dose melphalan injection. Intravitreal melphalan injections should be cautiously used for eyes with refractory seeds, particularly when multiple injections are required to control retinoblastoma seeds. Dose- related retinal toxicity could occur in pre-treated eyes even when a relatively low standard dose is used. Such patients should be followed up closely to monitor the treatment response and to assess potential delayed toxicity.

Short-term effects of intravitreal bevacizumab on cornea and anterior chamber.

PubMed

Güler, Mete; Capkın, Musa; Simşek, Ali; Bilak, Semsettin; Bilgin, Burak; Hakim Reyhan, Ali; Fırat, Müge

2014-10-01

To determine the short-term effects of single-dose intravitreal bevacizumab injection on central corneal thickness (CCT), simulated keratometry (Sim K), anterior chamber depth (ACD), iridocorneal angle (ICA) and intraocular pressure (IOP) measurements. Prospective, nonrandomized, interventional clinical trial. Forty-three eyes of 43 patients aged between 41 and 78 years (average 62 ± 13 years) received an intravitreal injection of 2.5 mg/0.1 mL bevacizumab. Patients who had not undergone additional intravitreal anti-vascular endothelial growth factor therapy within 6 months were included in the study. CCT, Sim K, ACD and ICA measurements were obtained with Sirius Topographer. IOP measurements were taken after topographic measurements with Goldmann applanation tonometer. The CCT, ACD, ICA and IOP measurements were taken before and after 3rd, 15th days and 1st month of intravitreal bevacizumab injection. Pre- and postinjection of 3rd, 15th days and 1st month CCT (p = 0.999), Sim K (p = 0.746), ACD (p = 0.996), ICA (p = 0.632) and IOP (p = 0.707) measurements were not statistically different. Mean CCT (p = 1.000), Sim K (0.972), ACD (p = 0.998), ICA (0.667) and IOP (0.951) values were similar before and after 3rd day of bevacizumab injection. Mean CCT (p = 0.999), Sim K (p = 0.994), ACD (p = 1.000), ICA (p = 0.999) and IOP (p = 1.000) measurements were also similar before and after 15th day of injection. Preinjection and 1st month of postinjection CCT (p = 0.999), Sim K (p = 0.932), ACD (p = 0.998), ICA (p = 1.000) and IOP (p = 0.741) measurements did not change significantly. Single-dose intravitreal bevacizumab injection does not affect CCT, Sim K, ACD, ICA and IOP in short-term period.

Impact of baseline Diabetic Retinopathy Severity Scale scores on visual outcomes in the VIVID-DME and VISTA-DME studies.

PubMed

Staurenghi, Giovanni; Feltgen, Nicolas; Arnold, Jennifer J; Katz, Todd A; Metzig, Carola; Lu, Chengxing; Holz, Frank G

2017-10-19

To evaluate intravitreal aflibercept versus laser in subgroups of patients with baseline Diabetic Retinopathy Severity Scale (DRSS) scores ≤43, 47, and ≥53 in VIVID-DME and VISTA-DME. Patients with diabetic macular oedema were randomised to receive intravitreal aflibercept 2 mg every 4 weeks (2q4), intravitreal aflibercept 2 mg every 8 weeks after five initial monthly doses (2q8), or macular laser photocoagulation at baseline with sham injections at every visit. These post hoc analyses evaluate outcomes based on baseline DRSS scores in patients in the integrated dataset. The 2q4 and 2q8 treatment groups were also pooled. 748 patients had a baseline DRSS score based on fundus photographs (≤43, n=301; 47, n=153; ≥53, n=294). At week 100, the least squares mean difference between treatment groups (effect of intravitreal aflibercept above that of laser, adjusting for baseline best-corrected visual acuity) was 8.9 (95% CI 5.99 to 11.81), 9.7 (95% CI 5.54 to 13.91), and 11.0 (95% CI 7.96 to 14.1) letters in those with baseline DRSS scores ≤43, 47, and ≥53, respectively. The proportions of patients with ≥2 step DRSS score improvement were greater in the intravitreal aflibercept group versus laser, respectively, for those with baseline DRSS scores of ≤43 (13% vs 5.9%), 47 (25.8% vs 4.5%), and ≥53 (64.5% vs 28.4%). Regardless of baseline DRSS score, functional outcomes were superior in intravitreal aflibercept-treated patients, demonstrating consistent treatment benefit across various baseline levels of retinopathy. NCT01331681 and NCT01363440, Post-results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Establishment of mouse expanded potential stem cells

PubMed Central

Gao, Xuefei; Antunes, Liliana; Yu, Yong; Zhu, Zhexin; Wang, Juexuan; Kolodziejczyk, Aleksandra A.; Campos, Lia S.; Wang, Cui; Yang, Fengtang; Zhong, Zhen; Fu, Beiyuan; Eckersley-Maslin, Melanie A.; Woods, Michael; Tanaka, Yosuke; Chen, Xi; Wilkinson, Adam C.; Bussell, James; White, Jacqui; Ramirez-Solis, Ramiro; Reik, Wolf; Göttgens, Berthold; Teichmann, Sarah A.; Tam, Patrick P. L.; Nakauchi, Hiromitsu; Zou, Xiangang; Lu, Liming; Liu, Pentao

2018-01-01

Mouse embryonic stem cells derived from the epiblast1 contribute to the somatic lineages and the germline but are excluded from the extra-embryonic tissues that are derived from the trophectoderm and the primitive endoderm2 upon reintroduction to the blastocyst. Here we report that cultures of expanded potential stem cells can be established from individual eight-cell blastomeres, and by direct conversion of mouse embryonic stem cells and induced pluripotent stem cells. Remarkably, a single expanded potential stem cell can contribute both to the embryo proper and to the trophectoderm lineages in a chimaera assay. Bona fide trophoblast stem cell lines and extra-embryonic endoderm stem cells can be directly derived from expanded potential stem cells in vitro. Molecular analyses of the epigenome and single-cell transcriptome reveal enrichment for blastomere-specific signature and a dynamic DNA methylome in expanded potential stem cells. The generation of mouse expanded potential stem cells highlights the feasibility of establishing expanded potential stem cells for other mammalian species. PMID:29019987

High Variation of Intravitreal Injection Rates and Medicare Anti-Vascular Endothelial Growth Factor Payments per Injection in the United States.

PubMed

Erie, Jay C; Barkmeier, Andrew J; Hodge, David O; Mahr, Michael A

2016-06-01

To estimate geographic variation of intravitreal injection rates and Medicare anti-vascular endothelial growth factor (VEGF) drug costs per injection in aging Americans. Observational cohort study using 2013 Medicare claims database. United States fee-for-service (FFS) Part B Medicare beneficiaries and their providers. Medicare Provider Utilization and Payment Data furnished by the Centers for Medicare and Medicaid Services was used to identify all intravitreal injection claims and anti-VEGF drug claims among FFS Medicare beneficiaries in all 50 states and the District of Columbia in 2013. The rate of FFS Medicare beneficiaries receiving intravitreal injections and the mean Medicare-allowed drug payment per anti-VEGF injection was calculated nationally and for each state. Geographic variations were evaluated by using extremal quotient, coefficient of variation, and systematic component of variance (SCV). Rate of FFS Medicare Part B beneficiaries receiving intravitreal injections (Current Procedural Terminology [CPT] code, 67028), nationally and by state; mean Medicare-allowed drug payment per anti-VEGF injection (CPT code, 67028; and treatment-specific J-codes, J0178, J2778, J9035, J3490, and J3590) nationally and by state. In 2013, the rate of FFS Medicare beneficiaries receiving intravitreal injections varied widely by 7-fold across states (range by state, 4 per 1000 [Wyoming]-28 per 1000 [Utah]), averaging 19 per 1000 beneficiaries. The mean SCV was 8.5, confirming high nonrandom geographic variation. There were more than 2.1 million anti-VEGF drug claims, totaling more than $2.3 billion in Medicare payments for anti-VEGF agents in 2013. The mean national Medicare drug payment per anti-VEGF injection varied widely by 6.2-fold across states (range by state, $242 [South Carolina]-$1509 [Maine]), averaging $1078 per injection. Nationally, 94% of injections were office based and 6% were facility based. High variation was observed in intravitreal injection rates and in Medicare drug payments per anti-VEGF injection across the United States in 2013. Identifying factors that contribute to high variation may help the ophthalmology community to optimize further the delivery and use of anti-VEGF agents. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Adult Stem Cell Therapy for Stroke: Challenges and Progress

PubMed Central

Bang, Oh Young; Kim, Eun Hee; Cha, Jae Min; Moon, Gyeong Joon

2016-01-01

Stroke is one of the leading causes of death and physical disability among adults. It has been 15 years since clinical trials of stem cell therapy in patients with stroke have been conducted using adult stem cells like mesenchymal stem cells and bone marrow mononuclear cells. Results of randomized controlled trials showed that adult stem cell therapy was safe but its efficacy was modest, underscoring the need for new stem cell therapy strategies. The primary limitations of current stem cell therapies include (a) the limited source of engraftable stem cells, (b) the presence of optimal time window for stem cell therapies, (c) inherited limitation of stem cells in terms of growth, trophic support, and differentiation potential, and (d) possible transplanted cell-mediated adverse effects, such as tumor formation. Here, we discuss recent advances that overcome these hurdles in adult stem cell therapy for stroke. PMID:27733032

Two sides of the same coin? Unraveling subtle differences between human embryonic and induced pluripotent stem cells by Raman spectroscopy.

PubMed

Parrotta, Elvira; De Angelis, Maria Teresa; Scalise, Stefania; Candeloro, Patrizio; Santamaria, Gianluca; Paonessa, Mariagrazia; Coluccio, Maria Laura; Perozziello, Gerardo; De Vitis, Stefania; Sgura, Antonella; Coluzzi, Elisa; Mollace, Vincenzo; Di Fabrizio, Enzo Mario; Cuda, Giovanni

2017-11-28

Human pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cells, hold enormous promise for many biomedical applications, such as regenerative medicine, drug testing, and disease modeling. Although induced pluripotent stem cells resemble embryonic stem cells both morphologically and functionally, the extent to which these cell lines are truly equivalent, from a molecular point of view, remains controversial. Principal component analysis and K-means cluster analysis of collected Raman spectroscopy data were used for a comparative study of the biochemical fingerprint of human induced pluripotent stem cells and human embryonic stem cells. The Raman spectra analysis results were further validated by conventional biological assays. Raman spectra analysis revealed that the major difference between human embryonic stem cells and induced pluripotent stem cells is due to the nucleic acid content, as shown by the strong positive peaks at 785, 1098, 1334, 1371, 1484, and 1575 cm -1 , which is enriched in human induced pluripotent stem cells. Here, we report a nonbiological approach to discriminate human induced pluripotent stem cells from their native embryonic stem cell counterparts.

A family business: stem cell progeny join the niche to regulate homeostasis.

PubMed

Hsu, Ya-Chieh; Fuchs, Elaine

2012-01-23

Stem cell niches, the discrete microenvironments in which the stem cells reside, play a dominant part in regulating stem cell activity and behaviours. Recent studies suggest that committed stem cell progeny become indispensable components of the niche in a wide range of stem cell systems. These unexpected niche inhabitants provide versatile feedback signals to their stem cell parents. Together with other heterologous cell types that constitute the niche, they contribute to the dynamics of the microenvironment. As progeny are often located in close proximity to stem cell niches, similar feedback regulations may be the underlying principles shared by different stem cell systems.

A family business: stem cell progeny join the niche to regulate homeostasis

PubMed Central

Hsu, Ya-Chieh; Fuchs, Elaine

2012-01-01

Stem cell niches, the discrete microenvironments in which the stem cells reside, play a dominant part in regulating stem cell activity and behaviours. Recent studies suggest that committed stem cell progeny become indispensable components of the niche in a wide range of stem cell systems. These unexpected niche inhabitants provide versatile feedback signals to their stem cell parents. Together with other heterologous cell types that constitute the niche, they contribute to the dynamics of the microenvironment. As progeny are often located in close proximity to stem cell niches, similar feedback regulations may be the underlying principles shared by different stem cell systems. PMID:22266760

Stem Cell Therapy for Erectile Dysfunction.

PubMed

Matz, Ethan L; Terlecki, Ryan; Zhang, Yuanyuan; Jackson, John; Atala, Anthony

2018-04-06

The prevalence of erectile dysfunction (ED) is substantial and continues to rise. Current therapeutics for ED consist of oral medications, intracavernosal injections, vacuum erection devices, and penile implants. While such options may manage the disease state, none of these modalities, however, restore function. Stem cell therapy has been evaluated for erectile restoration in animal models. These cells have been derived from multiple tissues, have varied potential, and may function via local engraftment or paracrine signaling. Bone marrow-derived stem cells (BMSC) and adipose-derived stem cells (ASC) have both been used in these models with noteworthy effects. Herein, we will review the pathophysiology of ED, animal models, current and novel stem-cell based therapeutics, clinical trials and areas for future research. The relevant literature and contemporary data using keywords, "stem cells and erectile dysfunction" was reviewed. Examination of evidence supporting the association between erectile dysfunction and adipose derived stem cells, bone marrow derived stem cells, placental stem cells, urine stem cells and stem cell therapy respectively. Placental-derived stem cells and urine-derived stem cells possess many similar properties as BMSC and ASC, but the methods of acquisition are favorable. Human clinical trials have already demonstrated successful use of stem cells for improvement of erectile function. The future of stem cell research is constantly being evaluated, although, the evidence suggests a place for stem cells in erectile dysfunction therapeutics. Matz EL, Terlecki R, Zhang Y, et al. Stem Cell Therapy for Erectile Dysfunction. Sex Med Rev 2018;XX:XXX-XXX. Copyright © 2018 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

A new prospect in cancer therapy: targeting cancer stem cells to eradicate cancer.

PubMed

Chen, Li-Sha; Wang, An-Xin; Dong, Bing; Pu, Ke-Feng; Yuan, Li-Hua; Zhu, Yi-Min

2012-12-01

According to the cancer stem cell theory, cancers can be initiated by cancer stem cells. This makes cancer stem cells prime targets for therapeutic intervention. Eradicating cancer stem cells by efficient targeting agents may have the potential to cure cancer. In this review, we summarize recent breakthroughs that have improved our understanding of cancer stem cells, and we discuss the therapeutic strategy of targeting cancer stem cells, a promising future direction for cancer stem cell research.

Adult bone marrow-derived stem cells for organ regeneration and repair.

PubMed

Tögel, Florian; Westenfelder, Christof

2007-12-01

Stem cells have been recognized as a potential tool for the development of innovative therapeutic strategies. There are in general two types of stem cells, embryonic and adult stem cells. While embryonic stem cell therapy has been riddled with problems of allogeneic rejection and ethical concerns, adult stem cells have long been used in the treatment of hematological malignancies. With the recognition of additional, potentially therapeutic characteristics, bone marrow-derived stem cells have become a tool in regenerative medicine. The bone marrow is an ideal source of stem cells because it is easily accessible and harbors two types of stem cells. Hematopoietic stem cells give rise to all blood cell types and have been shown to exhibit plasticity, while multipotent marrow stromal cells are the source of osteocytes, chondrocytes, and fat cells and have been shown to support and generate a large number of different cell types. This review describes the general characteristics of these stem cell populations and their current and potential future applications in regenerative medicine. 2007 Wiley-Liss, Inc

Stem cells.

PubMed

Behr, Björn; Ko, Sae Hee; Wong, Victor W; Gurtner, Geoffrey C; Longaker, Michael T

2010-10-01

Stem cells are self-renewing cells capable of differentiating into multiple cell lines and are classified according to their origin and their ability to differentiate. Enormous potential exists in use of stem cells for regenerative medicine. To produce effective stem cell-based treatments for a range of diseases, an improved understanding of stem cell biology and better control over stem cell fate are necessary. In addition, the barriers to clinical translation, such as potential oncologic properties of stem cells, need to be addressed. With renewed government support and continued refinement of current stem cell methodologies, the future of stem cell research is exciting and promises to provide novel reconstructive options for patients and surgeons limited by traditional paradigms.

Some Ethical Concerns About Human Induced Pluripotent Stem Cells.

PubMed

Zheng, Yue Liang

2016-10-01

Human induced pluripotent stem cells can be obtained from somatic cells, and their derivation does not require destruction of embryos, thus avoiding ethical problems arising from the destruction of human embryos. This type of stem cell may provide an important tool for stem cell therapy, but it also results in some ethical concerns. It is likely that abnormal reprogramming occurs in the induction of human induced pluripotent stem cells, and that the stem cells generate tumors in the process of stem cell therapy. Human induced pluripotent stem cells should not be used to clone human beings, to produce human germ cells, nor to make human embryos. Informed consent should be obtained from patients in stem cell therapy.

Laser biomodulation on stem cells

NASA Astrophysics Data System (ADS)

Liu, Timon C.; Duan, Rui; Li, Yan; Li, Xue-Feng; Tan, Li-Ling; Liu, Songhao

2001-08-01

Stem cells are views from the perspectives of their function, evolution, development, and cause. Counterintuitively, most stem cells may arise late in development, to act principally in tissue renewal, thus ensuring an organisms long-term survival. Surprisingly, recent reports suggest that tissue-specific adult stem cells have the potential to contribute to replenishment of multiple adult tissues. Stem cells are currently in the news for two reasons: the successful cultivation of human embryonic stem cell lines and reports that adult stem cells can differentiate into developmentally unrelated cell types, such as nerve cells into blood cells. The spotlight on stem cells has revealed gaps in our knowledge that must be filled if we are to take advantage of their full potential for treating devastating degenerative diseases such as Parkinsons's disease and muscular dystrophy. We need to know more about the intrinsic controls that keep stem cells as stem cells or direct them along particular differentiation pathways. Such intrinsic regulators are, in turn, sensitive to the influences of the microenvironment, or niche, where stem cells normally reside. Both intrinsic and extrinsic signals regular stem cell fate and some of these signals have now been identified. Vacek et al and Wang et al have studied the effect of low intensity laser on the haemopoietic stem cells in vitro. There experiments show there is indeed the effect of low intensity laser on the haemopoietic stem cells in vitro, and the present effect is the promotion of haemopoietic stem cells proliferation. In other words, low intensity laser irradiation can act as an extrinsic signal regulating stem cell fate. In this paper, we study how low intensity laser can be used to regulate stem cell fate from the viewpoint of collective phototransduction.

Potential antitumor therapeutic strategies of human amniotic membrane and amniotic fluid-derived stem cells.

PubMed

Kang, N-H; Hwang, K-A; Kim, S U; Kim, Y-B; Hyun, S-H; Jeung, E-B; Choi, K-C

2012-08-01

As stem cells are capable of self-renewal and can generate differentiated progenies for organ development, they are considered as potential source for regenerative medicine and tissue replacement after injury or disease. Along with this capacity, stem cells have the therapeutic potential for treating human diseases including cancers. According to the origins, stem cells are broadly classified into two types: embryonic stem cells (ESCs) and adult stem cells. In terms of differentiation potential, ESCs are pluripotent and adult stem cells are multipotent. Amnion, which is a membranous sac that contains the fetus and amniotic fluid and functions in protecting the developing embryo during gestation, is another stem cell source. Amnion-derived stem cells are classified as human amniotic membrane-derived epithelial stem cells, human amniotic membrane-derived mesenchymal stem cells and human amniotic fluid-derived stem cells. They are in an intermediate stage between pluripotent ESCs and lineage-restricted adult stem cells, non-tumorigenic, and contribute to low immunogenicity and anti-inflammation. Furthermore, they are easily available and do not cause any controversial issues in their recovery and applications. Not only are amnion-derived stem cells applicable in regenerative medicine, they have anticancer capacity. In non-engineered stem cells transplantation strategies, amnion-derived stem cells effectively target the tumor and suppressed the tumor growth by expressing cytotoxic cytokines. Additionally, they also have a potential as novel delivery vehicles transferring therapeutic genes to the cancer formation sites in gene-directed enzyme/prodrug combination therapy. Owing to their own advantageous properties, amnion-derived stem cells are emerging as a new candidate in anticancer therapy.

In vitro differentiation of primordial germ cells and oocyte-like cells from stem cells.

PubMed

Costa, José J N; Souza, Glaucinete B; Soares, Maria A A; Ribeiro, Regislane P; van den Hurk, Robert; Silva, José R V

2018-02-01

Infertility is the result of failure due to an organic disorder of the reproductive organs, especially their gametes. Recently, much progress has been made on generating germ cells, including oocytes, from various types of stem cells. This review focuses on advances in female germ cell differentiation from different kinds of stem cells, with emphasis on embryonic stem cells, adult stem cells, and induced pluripotent stem cells. The advantages and disadvantages of the derivation of female germ cells from several types of stem cells are also highlighted, as well as the ability of stem cells to generate mature and functional female gametes. This review shows that stem cell therapies have opened new frontiers in medicine, especially in the reproductive area, with the possibility of regenerating fertility.

Reduced hematopoietic stem cell frequency predicts outcome in acute myeloid leukemia.

PubMed

Wang, Wenwen; Stiehl, Thomas; Raffel, Simon; Hoang, Van T; Hoffmann, Isabel; Poisa-Beiro, Laura; Saeed, Borhan R; Blume, Rachel; Manta, Linda; Eckstein, Volker; Bochtler, Tilmann; Wuchter, Patrick; Essers, Marieke; Jauch, Anna; Trumpp, Andreas; Marciniak-Czochra, Anna; Ho, Anthony D; Lutz, Christoph

2017-09-01

In patients with acute myeloid leukemia and low percentages of aldehyde-dehydrogenase-positive cells, non-leukemic hematopoietic stem cells can be separated from leukemic cells. By relating hematopoietic stem cell frequencies to outcome we detected poor overall- and disease-free survival of patients with low hematopoietic stem cell frequencies. Serial analysis of matched diagnostic and follow-up samples further demonstrated that hematopoietic stem cells increased after chemotherapy in patients who achieved durable remissions. However, in patients who eventually relapsed, hematopoietic stem cell numbers decreased dramatically at the time of molecular relapse demonstrating that hematopoietic stem cell levels represent an indirect marker of minimal residual disease, which heralds leukemic relapse. Upon transplantation in immune-deficient mice cases with low percentages of hematopoietic stem cells of our cohort gave rise to leukemic or no engraftment, whereas cases with normal hematopoietic stem cell levels mostly resulted in multi-lineage engraftment. Based on our experimental data, we propose that leukemic stem cells have increased niche affinity in cases with low percentages of hematopoietic stem cells. To validate this hypothesis, we developed new mathematical models describing the dynamics of healthy and leukemic cells under different regulatory scenarios. These models suggest that the mechanism leading to decreases in hematopoietic stem cell frequencies before leukemic relapse must be based on expansion of leukemic stem cells with high niche affinity and the ability to dislodge hematopoietic stem cells. Thus, our data suggest that decreasing numbers of hematopoietic stem cells indicate leukemic stem cell persistence and the emergence of leukemic relapse. Copyright© 2017 Ferrata Storti Foundation.

Evaluation of the secretion and release of vascular endothelial growth factor from two-dimensional culture and three-dimensional cell spheroids formed with stem cells and osteoprecursor cells.

PubMed

Lee, Hyunjin; Lee, Sung-Il; Ko, Youngkyung; Park, Jun-Beom

2018-05-18

Co-culture has been applied in cell therapy, including stem cells, and has been reported to give enhanced functionality. In this study, stem-cell spheroids were formed in concave micromolds at different ratios of stem cells to osteoprecursor cells, and the amount of secretion of vascular endothelial growth factor (VEGF) was evaluated. Gingiva-derived stem cells and osteoprecursor cells in the amount of 6 × 105 were seeded on a 24-well culture plate or concave micromolds. The ratios of stem cells to osteoprecursor cells included: 0:4 (group 1), 1:3 (group 2), 2:2 (group 3), 3:1 (group 4), and 4:0 (group 5). The morphology of cells in a 2-dimensional culture (groups 1-5) showed a fibroblast-like appearance. The secretion of VEGF increased with the increase in stem cells, and a statistically significant increase was noted in groups 3, 4 and 5 when compared with the media-only group (p < 0.05). Osteoprecursor cells formed spheroids in concave microwells, and no noticeable change in the morphology was noted with the increase in stem cells. Spheroids containing stem cells were positive for the stem-cell markers SSEA-4. The secretion of VEGF from cell spheroids increased with the increase in stem cells. This study showed that cell spheroids formed with stem cells and osteoprecursor cells with different ratios, using microwells, had paracrine effects on the stem cells. The secretion of VEGF increased with the increase in stem cells. This stem-cell spheroid may be applied for tissue-engineering purposes.

Therapeutic potential of intravitreal pharmacotherapy in retinal vein occlusion

PubMed Central

Shahsuvaryan, Marianne L.

2012-01-01

Retinal vein occlusion (RVO) is the most common visually disabling disease affecting the retina after diabetic retinopathy. Although the disease entity has long been known, its management is still controversial. Macular edema is the main reason for decreased visual acuity (VA) in this retinal vascular disorder. Recently the vitreous cavity has increasingly been used as a reservoir of drugs for the direct treatment of macular edema through intravitreal injection route. The most widely injected drugs so far have been triamcinolone acetonide (TA) and bevacizumab. The objective of this review is to evaluate the evidence and discuss the rationale behind the recent suggestions that intravitreal pharmacotherapy by corticosteroids and anti-vascular endothelial growth factors may be useful in the treatment of retinal vein occlusion. PMID:23275914

The Role of Stem Cells in Aesthetic Surgery: Fact or Fiction?

PubMed Central

McArdle, Adrian; Senarath-Yapa, Kshemendra; Walmsley, Graham G.; Hu, Michael; Atashroo, David A.; Tevlin, Ruth; Zielins, Elizabeth; Gurtner, Geoffrey C.; Wan, Derrick C.; Longaker, Michael T.

2014-01-01

Stem cells are attractive candidates for the development of novel therapies, targeting indications that involve functional restoration of defective tissue. Although most stem cell therapies are new and highly experimental, there are clinics around the world that exploit vulnerable patients with the hope of offering supposed stem cell therapies, many of which operate without credible scientific merit, oversight, or other patient protection. We review the potential, as well as drawbacks, for incorporation of stem cells in cosmetic procedures. A review of FDA-approved indications and ongoing clinical trials with adipose stem cells is provided. Furthermore, a “snapshot” analysis of websites using the search terms “stem cell therapy” or “stem cell treatment” or “stem cell facelift” was performed. Despite the protective net cast by regulatory agencies such as the FDA and professional societies such as the American Society of Plastic Surgeons, we are witnessing worrying advertisements for procedures such as stem cell facelifts, stem cell breast augmentations, and even stem cell vaginal rejuvenation. The marketing and promotion of stem cell procedures in aesthetic surgery is not adequately supported by clinical evidence in the majority of cases. Stem cells offer tremendous potential, but the marketplace is saturated with unsubstantiated and sometimes fraudulent claims that may place patients at risk. With plastic surgeons at the forefront of stem cell-based regenerative medicine, it is critically important that we provide an example of a rigorous approach to research, data collection, and advertising of stem cell therapies. PMID:24732654

A WUSCHEL-Independent Stem Cell Specification Pathway Is Repressed by PHB, PHV and CNA in Arabidopsis.

PubMed

Lee, Chunghee; Clark, Steven E

2015-01-01

The homeostatic maintenance of stem cells that carry out continuous organogenesis at the shoot meristem is crucial for plant development. Key known factors act to signal between the stem cells and an underlying group of cells thought to act as the stem cell niche. In Arabidopsis thaliana the homeodomain transcription factor WUSCHEL (WUS) is essential for stem cell initiation and maintenance at shoot and flower meristems. Recent data suggest that the WUS protein may move from the niche cells directly into the stem cells to maintain stem cell identity. Here we provide evidence for a second, previously unknown, pathway for stem cell specification at shoot and flower meristems that bypasses the requirement for WUS. We demonstrate that this novel stem cell specification pathway is normally repressed by the activity of the HD-zip III transcription factors PHABULOSA (PHB), PHAVOLUTA (PHV) and CORONA (CNA). When de-repressed, this second stem cell pathway leads to an accumulation of stem cells and an enlargement of the stem cell niche. When de-repressed in a wus mutant background, this second stem cell pathway leads to functional meristems with largely normal cell layering and meristem morphology, activation of WUS cis regulatory elements, and extensive, but not indeterminate, organogenesis. Thus, WUS is largely dispensable for stem cell specification and meristem function, suggesting a set of key stem cell specification factors, competitively regulated by WUS and PHB/PHV/CNA, remain unidentified.

A WUSCHEL-Independent Stem Cell Specification Pathway Is Repressed by PHB, PHV and CNA in Arabidopsis

PubMed Central

Lee, Chunghee; Clark, Steven E.

2015-01-01

The homeostatic maintenance of stem cells that carry out continuous organogenesis at the shoot meristem is crucial for plant development. Key known factors act to signal between the stem cells and an underlying group of cells thought to act as the stem cell niche. In Arabidopsis thaliana the homeodomain transcription factor WUSCHEL (WUS) is essential for stem cell initiation and maintenance at shoot and flower meristems. Recent data suggest that the WUS protein may move from the niche cells directly into the stem cells to maintain stem cell identity. Here we provide evidence for a second, previously unknown, pathway for stem cell specification at shoot and flower meristems that bypasses the requirement for WUS. We demonstrate that this novel stem cell specification pathway is normally repressed by the activity of the HD-zip III transcription factors PHABULOSA (PHB), PHAVOLUTA (PHV) and CORONA (CNA). When de-repressed, this second stem cell pathway leads to an accumulation of stem cells and an enlargement of the stem cell niche. When de-repressed in a wus mutant background, this second stem cell pathway leads to functional meristems with largely normal cell layering and meristem morphology, activation of WUS cis regulatory elements, and extensive, but not indeterminate, organogenesis. Thus, WUS is largely dispensable for stem cell specification and meristem function, suggesting a set of key stem cell specification factors, competitively regulated by WUS and PHB/PHV/CNA, remain unidentified. PMID:26011610

Generation, characterization and potential therapeutic applications of mature and functional hepatocytes from stem cells.

PubMed

Zhang, Zhenzhen; Liu, Jianfang; Liu, Yang; Li, Zheng; Gao, Wei-Qiang; He, Zuping

2013-02-01

Liver cancer is the sixth most common tumor in the world and the majority of patients with this disease usually die within 1 year. The effective treatment for end-stage liver disease (also known as liver failure), including liver cancer or cirrhosis, is liver transplantation. However, there is a severe shortage of liver donors worldwide, which is the major handicap for the treatment of patients with liver failure. Scarcity of liver donors underscores the urgent need of using stem cell therapy to the end-stage liver disease. Notably, hepatocytes have recently been generated from hepatic and extra-hepatic stem cells. We have obtained mature and functional hepatocytes from rat hepatic stem cells. Here, we review the advancements on hepatic differentiation from various stem cells, including hepatic stem cells, embryonic stem cells, the induced pluripotent stem cells, hematopoietic stem cells, mesenchymal stem cells, and probably spermatogonial stem cells. The advantages, disadvantages, and concerns on differentiation of these stem cells into hepatic cells are highlighted. We further address the methodologies, phenotypes, and functional characterization on the differentiation of numerous stem cells into hepatic cells. Differentiation of stem cells into mature and functional hepatocytes, especially from an extra-hepatic stem cell source, would circumvent the scarcity of liver donors and human hepatocytes, and most importantly it would offer an ideal and promising source of hepatocytes for cell therapy and tissue engineering in treating liver disease. Copyright © 2012 Wiley Periodicals, Inc.

Stem cells in dentistry--part I: stem cell sources.

PubMed

Egusa, Hiroshi; Sonoyama, Wataru; Nishimura, Masahiro; Atsuta, Ikiru; Akiyama, Kentaro

2012-07-01

Stem cells can self-renew and produce different cell types, thus providing new strategies to regenerate missing tissues and treat diseases. In the field of dentistry, adult mesenchymal stem/stromal cells (MSCs) have been identified in several oral and maxillofacial tissues, which suggests that the oral tissues are a rich source of stem cells, and oral stem and mucosal cells are expected to provide an ideal source for genetically reprogrammed cells such as induced pluripotent stem (iPS) cells. Furthermore, oral tissues are expected to be not only a source but also a therapeutic target for stem cells, as stem cell and tissue engineering therapies in dentistry continue to attract increasing clinical interest. Part I of this review outlines various types of intra- and extra-oral tissue-derived stem cells with regard to clinical availability and applications in dentistry. Additionally, appropriate sources of stem cells for regenerative dentistry are discussed with regard to differentiation capacity, accessibility and possible immunomodulatory properties. Copyright © 2012 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Plant stem cell niches.

PubMed

Stahl, Yvonne; Simon, Rüdiger

2005-01-01

Stem cells are required to support the indeterminate growth style of plants. Meristems are a plants stem cell niches that foster stem cell survival and the production of descendants destined for differentiation. In shoot meristems, stem cell fate is decided at the populational level. The size of the stem cell domain at the meristem tip depends on signals that are exchanged with cells of the organizing centre underneath. In root meristems, individual stem cells are controlled by direct interaction with cells of the quiescent centre that lie in the immediate neighbourhood. Analysis of the interactions and signaling processes in the stem cell niches has delivered some insights into the molecules that are involved and revealed that the two major niches for plant stem cells are more similar than anticipated.

Intravitreal delivery of AAV-NDI1 provides functional benefit in a murine model of Leber hereditary optic neuropathy.

PubMed

Chadderton, Naomi; Palfi, Arpad; Millington-Ward, Sophia; Gobbo, Oliverio; Overlack, Nora; Carrigan, Matthew; O'Reilly, Mary; Campbell, Matthew; Ehrhardt, Carsten; Wolfrum, Uwe; Humphries, Peter; Kenna, Paul F; Farrar, G Jane

2013-01-01

Leber hereditary optic neuropathy (LHON) is a mitochondrially inherited form of visual dysfunction caused by mutations in several genes encoding subunits of the mitochondrial respiratory NADH-ubiquinone oxidoreductase complex (complex I). Development of gene therapies for LHON has been impeded by genetic heterogeneity and the need to deliver therapies to the mitochondria of retinal ganglion cells (RGCs), the cells primarily affected in LHON. The therapy under development entails intraocular injection of a nuclear yeast gene NADH-quinone oxidoreductase (NDI1) that encodes a single subunit complex I equivalent and as such is mutation independent. NDI1 is imported into mitochondria due to an endogenous mitochondrial localisation signal. Intravitreal injection represents a clinically relevant route of delivery to RGCs not previously used for NDI1. In this study, recombinant adenoassociated virus (AAV) serotype 2 expressing NDI1 (AAV-NDI1) was shown to protect RGCs in a rotenone-induced murine model of LHON. AAV-NDI1 significantly reduced RGC death by 1.5-fold and optic nerve atrophy by 1.4-fold. This led to a significant preservation of retinal function as assessed by manganese enhanced magnetic resonance imaging and optokinetic responses. Intraocular injection of AAV-NDI1 overcomes many barriers previously associated with developing therapies for LHON and holds great therapeutic promise for a mitochondrial disorder for which there are no effective therapies.

Experimental uveitis can be maintained in rabbits for a period of six weeks after a safe sensitization method.

PubMed

Eperon, S; Balaskas, K; Vaudaux, J; Guex-Crosier, Y

2013-03-01

New treatments against long-lasting uveitis need to be tested. Our aim was to develop a six-week model of uveitis in rabbits. Rabbits were presensitized with an s.c. injection of Mycobacterium tuberculosis H37RA emulsified with TiterMax Gold adjuvant. Uveitis was induced at day 28 and 50, by intravitreal challenges of antigen suspension. Ocular inflammation was assessed till euthanasia at day 71 after s.c. injection of M. tuberculosis H37RA by: (a) the number of inflammatory cells in aqueous humor (AH); (b) the protein concentration in AH; (c) the clinical score (mean of conjunctival hyperaemia, conjunctival chemosis, oedema and secretion); (d) the microscopical score (mean presence of fibrin and synechiae, aqueous cell density and aqueous flare grade, as scored by slit lamp). At the sites of presensitization injection, rabbits presented flat nodules which progressively vanished. The first challenge induced a significant increase in the four parameters (p < 0.05 the Wilcoxon/Kruskal-Wallis test). The AH contained 764 ± 82 cells/µl and 32 ± 0.77 mg protein/ml. During the following days, inflammatory parameters decreased slightly. The second intravitreal challenge increased inflammation (3564 ± 228 cells/µl AH and 31 ± 1 mg protein/ml), which remained at a high level for a longer period of time. We developed a model of long-term uveitis, which could be maintained in rabbits for at least six weeks. Such a model could be used to test the efficacy of either new drugs or various drug delivery systems intended to deliver active agents during a few months.

TPL2 (Therapeutic Targeting Tumor Progression Locus-2)/ATF4 (Activating Transcription Factor-4)/SDF1α (Chemokine Stromal Cell-Derived Factor-α) Axis Suppresses Diabetic Retinopathy.

PubMed

Lai, De-Wei; Lin, Keng-Hung; Sheu, Wayne Huey-Herng; Lee, Maw-Rong; Chen, Chung-Yu; Lee, Wen-Jane; Hung, Yi-Wen; Shen, Chin-Chang; Chung, Tsung-Ju; Liu, Shing-Hwa; Sheu, Meei-Ling

2017-09-01

Diabetic retinopathy is characterized by vasopermeability, vascular leakage, inflammation, blood-retinal barrier breakdown, capillary degeneration, and neovascularization. However, the mechanisms underlying the association between diabetes mellitus and progression retinopathy remain unclear. TPL2 (tumor progression locus 2), a serine-threonine protein kinase, exerts a pathological effect on vascular angiogenesis. This study investigated the role of N ε -(carboxymethyl)lysine, a major advanced glycation end products, and the involved TPL2-related molecular signals in diabetic retinopathy using models of in vitro and in vivo and human samples. Serum N ε -(carboxymethyl)lysine levels and TPL2 kinase activity were significantly increased in clinical patients and experimental animals with diabetic retinopathy. Intravitreal administration of pharmacological blocker or neutralizing antibody inhibited TPL2 and effectively suppressed the pathological characteristics of retinopathy in streptozotocin-induced diabetic animal models. Intravitreal VEGF (vascular endothelial growth factor) neutralization also suppressed the diabetic retinopathy in diabetic animal models. Mechanistic studies in primary human umbilical vein endothelial cells and primary retinal microvascular endothelial cells from streptozotocin-diabetic rats, db/db mice, and samples from patients with diabetic retinopathy revealed a positive parallel correlation between N ε -(carboxymethyl)lysine and the TPL2/chemokine SDF1α (stromal cell-derived factor-α) axis that is dependent on endoplasmic reticulum stress-related molecules, especially ATF4 (activating transcription factor-4). This study demonstrates that inhibiting the N ε -(carboxymethyl)lysine-induced TPL2/ATF4/SDF1α axis can effectively prevent diabetes mellitus-mediated retinal microvascular dysfunction. This signaling axis may include the therapeutic potential for other diseases involving pathological neovascularization or macular edema. © 2017 American Heart Association, Inc.

Decursin inhibits retinal neovascularization via suppression of VEGFR-2 activation.

PubMed

Kim, Jeong Hun; Kim, Jin Hyoung; Lee, You Mie; Ahn, Eun-Mi; Kim, Kyu-Won; Yu, Young Suk

2009-09-12

Pathologic angiogenesis in the retina leads to the catastrophic loss of vision. Retinopathy of prematurity (ROP), a vasoproliferative retinopathy, is a leading cause of blindness in children. We evaluated the inhibitory effect of decursin on retinal neovascularization. Anti-angiogenic activity of decursin was evaluated by vascular endothelial growth factor (VEGF)-induced proliferation, migration, and in vitro tube formation assay of human retinal microvascular endothelial cells (HRMECs). We also used western blot analysis to assess inhibition of vascular endothelial growth factor receptor-2 (VEGFR-2) phosphorylation by decursin. After intravitreal injection of decursin in a mouse model of ROP, retinal neovascularization was examined by fluorescence angiography and vessel counting in cross-sections. The toxicity of decursin was evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in HRMECs as well as histologic and immunohistochemistry examination for glial fibrillary acidic protein in the retina. Decursin significantly inhibited VEGF-induced proliferation, migration, and the formation of capillary-like networks of retinal endothelial cells in a dose-dependent manner. Decursin inhibited VEGF-induced phosphorylation of VEGFR-2, blocking the VEGFR-2 signaling pathway. When intravitreously injected, decursin dramatically suppressed retinal neovascularization in a mouse model of ROP. Even in a high concentration, decursin never induced any structural or inflammatory changes to cells in retinal or vitreous layers. Moreover, the upregulation of glial fibrillary acidic protein expression was not detected in Mueller cells. Our data suggest that decursin may be a potent anti-angiogenic agent targeting the VEGFR-2 signaling pathway, which significantly inhibits retinal neovascularization without retinal toxicity and may be applicable in various other vasoproliferative retinopathies as well.

Decursin inhibits retinal neovascularization via suppression of VEGFR-2 activation

PubMed Central

Kim, Jeong Hun; Kim, Jin Hyoung; Lee, You Mie; Ahn, Eun-Mi; Kim, Kyu-Won

2009-01-01

Purpose Pathologic angiogenesis in the retina leads to the catastrophic loss of vision. Retinopathy of prematurity (ROP), a vasoproliferative retinopathy, is a leading cause of blindness in children. We evaluated the inhibitory effect of decursin on retinal neovascularization. Methods Anti-angiogenic activity of decursin was evaluated by vascular endothelial growth factor (VEGF)-induced proliferation, migration, and in vitro tube formation assay of human retinal microvascular endothelial cells (HRMECs). We also used western blot analysis to assess inhibition of vascular endothelial growth factor receptor-2 (VEGFR-2) phosphorylation by decursin. After intravitreal injection of decursin in a mouse model of ROP, retinal neovascularization was examined by fluorescence angiography and vessel counting in cross-sections. The toxicity of decursin was evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in HRMECs as well as histologic and immunohistochemistry examination for glial fibrillary acidic protein in the retina. Results Decursin significantly inhibited VEGF-induced proliferation, migration, and the formation of capillary-like networks of retinal endothelial cells in a dose-dependent manner. Decursin inhibited VEGF-induced phosphorylation of VEGFR-2, blocking the VEGFR-2 signaling pathway. When intravitreously injected, decursin dramatically suppressed retinal neovascularization in a mouse model of ROP. Even in a high concentration, decursin never induced any structural or inflammatory changes to cells in retinal or vitreous layers. Moreover, the upregulation of glial fibrillary acidic protein expression was not detected in Mueller cells. Conclusions Our data suggest that decursin may be a potent anti-angiogenic agent targeting the VEGFR-2 signaling pathway, which significantly inhibits retinal neovascularization without retinal toxicity and may be applicable in various other vasoproliferative retinopathies as well. PMID:19756180

Stem cells in the Drosophila digestive system.

PubMed

Zeng, Xiankun; Chauhan, Chhavi; Hou, Steven X

2013-01-01

Adult stem cells maintain tissue homeostasis by continuously replenishing damaged, aged and dead cells in any organism. Five types of region and organ-specific multipotent adult stem cells have been identified in the Drosophila digestive system: intestinal stem cells (ISCs) in the posterior midgut; hindgut intestinal stem cells (HISCs) at the midgut/hindgut junction; renal and nephric stem cells (RNSCs) in the Malpighian Tubules; type I gastric stem cells (GaSCs) at foregut/midgut junction; and type II gastric stem cells (GSSCs) at the middle of the midgut. Despite the fact that each type of stem cell is unique to a particular organ, they share common molecular markers and some regulatory signaling pathways. Due to the simpler tissue structure, ease of performing genetic analysis, and availability of abundant mutants, Drosophila serves as an elegant and powerful model system to study complex stem cell biology. The recent discoveries, particularly in the Drosophila ISC system, have greatly advanced our understanding of stem cell self-renewal, differentiation, and the role of stem cells play in tissue homeostasis/regeneration and adaptive tissue growth.

Induced cancer stem cells generated by radiochemotherapy and their therapeutic implications.

PubMed

Chen, Xiewan; Liao, Rongxia; Li, Dezhi; Sun, Jianguo

2017-03-07

Local and distant recurrence of malignant tumors following radio- and/or chemotherapy correlates with poor prognosis of patients. Among the reasons for cancer recurrence, preexisting cancer stem cells (CSCs) are considered the most likely cause due to their properties of self-renewal, pluripotency, plasticity and tumorigenicity. It has been demonstrated that preexisting cancer stem cells derive from normal stem cells and differentiated somatic cells that undergo transformation and dedifferentiation respectively under certain conditions. However, recent studies have revealed that cancer stem cells can also be induced from non-stem cancer cells by radiochemotherapy, constituting the subpopulation of induced cancer stem cells (iCSCs). These findings suggest that radiochemotherapy has the side effect of directly transforming non-stem cancer cells into induced cancer stem cells, possibly contributing to tumor recurrence and metastasis. Therefore, drugs targeting cancer stem cells or preventing dedifferentiation of non-stem cancer cells can be combined with radiochemotherapy to improve its antitumor efficacy. The current review is to investigate the mechanisms by which induced cancer stem cells are generated by radiochemotherapy and hence provide new strategies for cancer treatment.

Stem cells in gastroenterology and hepatology

PubMed Central

Quante, Michael; Wang, Timothy C.

2010-01-01

Cellular and tissue regeneration in the gastrointestinal tract and liver depends on stem cells with properties of longevity, self-renewal and multipotency. Progress in stem cell research and the identification of potential esophageal, gastric, intestinal, colonic, hepatic and pancreatic stem cells provides hope for the use of stem cells in regenerative medicine and treatments for disease. Embryonic stem cells and induced pluripotent stem cells have the potential to give rise to any cell type in the human body, but their therapeutic application remains challenging. The use of adult or tissue-restricted stem cells is emerging as another possible approach for the treatment of gastrointestinal diseases. The same self-renewal properties that allow stem cells to remain immortal and generate any tissue can occasionally make their proliferation difficult to control and make them susceptible to malignant transformation. This Review provides an overview of the different types of stem cell, focusing on tissue-restricted adult stem cells in the fields of gastroenterology and hepatology and summarizing the potential benefits and risks of using stems cells to treat gastroenterological and liver disorders. PMID:19884893

Lower Oncogenic Potential of Human Mesenchymal Stem Cells Derived from Cord Blood Compared to Induced Pluripotent Stem Cells

PubMed Central

Foroutan, T.; Najmi, M.; Kazemi, N.; Hasanlou, M.; Pedram, A.

2015-01-01

Background: In regenerative medicine, use of each of the mesenchymal stem cells derived from bone marrow, cord blood, and adipose tissue, has several cons and pros. Mesenchymal stem cells derived from cord blood have been considered the best source for precursor transplantation. Direct reprogramming of a somatic cell into induced pluripotent stem cells by over-expression of 6 transcription factors Oct4, Sox2, Klf4, lin28, Nanog, and c-Myc has great potential for regenerative medicine, eliminating the ethical issues of embryonic stem cells and the rejection problems of using non-autologous cells. Objective: To compare reprogramming and pluripotent markers OCT4, Sox-2, c-Myc, Klf4, Nanog, and lin28 in mesenchymal stem cells derived from cord blood and induced pluripotent stem cells. Methods: We analyzed the expression level of OCT4, Sox-2, c-Myc, Klf4, Nanog and lin28 genes in human mesenchymal stem cells derived from cord blood and induced pluripotent stem cells by cell culture and RT-PCR. Results: The expression level of pluripotent genes OCT4 and Sox-2, Nanog and lin28 in mesenchymal stem cells derived from cord blood were significantly higher than those in induced pluripotent stem cells. In contrast to OCT-4A and Sox-2, Nanog and lin28, the expression level of oncogenic factors c-Myc and Klf4 were significantly higher in induced pluripotent stem cells than in mesenchymal stem cells derived from cord blood. Conclusion: It could be concluded that mesenchymal stem cells derived from human cord blood have lower oncogenic potential compared to induced pluripotent stem cells. PMID:26306155

Eckol suppresses maintenance of stemness and malignancies in glioma stem-like cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyun, Kyung-Hwan; Yoon, Chang-Hwan; Kim, Rae-Kwon

A subpopulation of cancer cells with stem cell properties is responsible for tumor maintenance and progression, and may contribute to resistance to anticancer treatments. Thus, compounds that target cancer stem-like cells could be usefully applied to destroy cancer. In this study, we investigated the effect of Eckol, a phlorotannin compound, on stemness and malignancies in glioma stem-like cells. To determine whether Eckol targets glioma stem-like cells, we examined whether Eckol treatment could change the expression levels of glioma stem-like cell markers and self-renewal-related proteins as well as the sphere forming ability, and the sensitivity to anticancer treatments. Alterations in themore » malignant properties of sphere-derived cells by Eckol were also investigated by soft-agar colony forming assay, by xenograft assay in nude mice, and by cell invasion assay. Treatment of sphere-forming glioma cells with Eckol effectively decreased the sphere formation as well as the CD133{sup +} cell population. Eckol treatment suppressed expression of the glioma stem-like cell markers and the self-renewal-related proteins without cell death. Moreover, treatment of glioma stem-like cells with Eckol significantly attenuated anchorage-independent growth on soft agar and tumor formation in xenograft mice. Importantly, Eckol treatment effectively reduced the resistance of glioma stem-like cells to ionizing radiation and temozolomide. Treatment of glioma stem-like cells with Eckol markedly blocked both phosphoinositide 3-kinase-Akt and Ras-Raf-1-Erk signaling pathways. These results indicate that the natural phlorotannin Eckol suppresses stemness and malignancies in glioma stem-like cells, and thereby makes glioma stem-like cells more sensitive to anticancer treatments, providing novel therapeutic strategies targeting specifically cancer stem-like cells.« less

Flagellin preconditioning enhances the efficacy of mesenchymal stem cells in an irradiation-induced proctitis model.

PubMed

Linard, Christine; Strup-Perrot, Carine; Lacave-Lapalun, Jean-Victor; Benderitter, Marc

2016-09-01

The success of mesenchymal stem cell transplantation for proctitis depends not only on cell donors but also on host microenvironmental factors, which play a major role in conditioning mesenchymal stem cell immunosuppressive action and repair. This study sought to determine if flagellin, a TLR5 ligand, can enhance the mesenchymal stem cell treatment efficacy in radiation-induced proctitis. With the use of a colorectal model of 27 Gy irradiation in rats, we investigated and compared the effects on immune capacity and remodeling at 28 d after irradiation of the following: 1) systemic mesenchymal stem cell (5 × 10(6)) administration at d 7 after irradiation, 2) administration of flagellin at d 3 and systemic mesenchymal stem cell administration at d 7, and 3) in vitro preconditioning of mesenchymal stem cells with flagellin, 24 h before their administration on d 7. The mucosal CD8(+) T cell population was normalized after treatment with flagellin-preconditioned mesenchymal stem cells or flagellin plus mesenchymal stem cells, whereas mesenchymal stem cells alone did not alter the radiation-induced elevation of CD8(+) T cell frequency. Mesenchymal stem cell treatment returned the irradiation-elevated frequency of CD25(+) cells in the mucosa-to-control levels, whereas both flagellin-preconditioned mesenchymal stem cell and flagellin-plus-mesenchymal stem cell treatment each significantly increased not only CD25(+) cell frequency but also forkhead box p3 and IL-2Rα expression. Specifically, IL-10 was overexpressed after flagellin-preconditioned mesenchymal stem cell treatment. Analysis of collagen expression showed that the collagen type 1/collagen type 3 ratio, an indicator of wound-healing maturation, was low in the irradiated and mesenchymal stem cell-treated groups and returned to the normal level only after the flagellin-preconditioned mesenchymal stem cell treatment. This was associated with a reduction in myofibroblast accumulation. In a proctitis model, flagellin-preconditioned mesenchymal stem cells improved colonic immune capacity and enhanced tissue remodeling. © Society for Leukocyte Biology.

Epidermal stem cells: location, potential and contribution to cancer.

PubMed

Ambler, C A; Määttä, A

2009-01-01

Epidermal stem cells have been classically characterized as slow-cycling, long-lived cells that reside in discrete niches in the skin. Gene expression studies of niche-resident cells have revealed a number of stem cell markers and regulators, including the Wnt/beta-catenin, Notch, p63, c-Myc and Hedgehog pathways. A new study challenges the traditional developmental paradigm of slow-cycling stem cells and rapid-cycling transit amplifying cells in some epidermal regions, and there is mounting evidence to suggest that multi-lineage epidermal progenitors can be isolated from highly proliferative, non-niche regions. Whether there is a unique microenvironment surrounding these progenitors remains to be determined. Interestingly, cancer stem cells derived from epidermal tumours exist independent of the classic skin stem cell niche, yet also have stem cell properties, including multi-lineage differentiation. This review summarizes recent studies identifying the location and regulators of mouse and human epidermal stem cells and highlights the strategies used to identify cancer stem cells, including expression of normal epidermal stem cell markers, expression of cancer stem cell markers identified in other epidermal tumours and characterization of side-population tumour cells.

MicroRNAs: key regulators of stem cells.

PubMed

Gangaraju, Vamsi K; Lin, Haifan

2009-02-01

The hallmark of a stem cell is its ability to self-renew and to produce numerous differentiated cells. This unique property is controlled by dynamic interplays between extrinsic signalling, epigenetic, transcriptional and post-transcriptional regulations. Recent research indicates that microRNAs (miRNAs) have an important role in regulating stem cell self-renewal and differentiation by repressing the translation of selected mRNAs in stem cells and differentiating daughter cells. Such a role has been shown in embryonic stem cells, germline stem cells and various somatic tissue stem cells. These findings reveal a new dimension of gene regulation in controlling stem cell fate and behaviour.

Primary central nervous system lymphoma.

PubMed

Ahluwalia, Manmeet S; Peereboom, David M

2010-07-01

Management goals for patients with primary central nervous system lymphoma (PCNSL) include long-term disease control, management of neurologic complications, and preservation of neurocognitive function. Various treatment options can achieve several of these goals. Chemotherapy as monotherapy or as combination therapy has emerged as the cornerstone of therapy for patients with newly diagnosed PCNSL. Outside of a clinical trial, patients with newly diagnosed PCNSL should receive high-dose intravenous methotrexate (MTX) as a single agent or as part of a combination regimen with radiation therapy reserved for relapse. The regimen should have an adequate MTX dose (>3 g/m(2)) to reach cytotoxic concentrations in the cerebrospinal fluid (CSF) to treat occult leptomeningeal disease (LMD). Alternative modes of chemotherapy delivery for selected patients, preferably in the context of a clinical trial, include high-dose chemotherapy with autologous stem cell rescue and intra-arterial chemotherapy with blood-brain barrier disruption. Whole brain radiation therapy (WBRT) in standard doses and fractionation carries an unacceptable rate of long-term neurocognitive toxicity. However, lower doses in daily divided fractions may offer the possibility of adding this modality with preservation of cognition but should be performed only in the context of a clinical trial. The long-term efficacy and toxicity of this approach is currently under investigation. Certain presentations of PCNSL require different strategies. Patients with ocular lymphoma at diagnosis should receive high-dose MTX as this drug can reach cytotoxic intravitreal concentrations. Recurrence in the eyes is managed with intravitreal chemotherapy including MTX or rituximab or with radiation therapy. The field of treatment (eyes vs whole brain) should be individualized. Intrathecal (IT) MTX should be included in the treatment regimen for those patients with a positive CSF cytology, or in regimens in which lower doses of MTX are delivered over longer periods of time. It is probably reasonable to withhold IT chemotherapy in those patients who have no detectable subarachnoid disease and who can receive higher doses of MTX (>3 g/m(2)) over shorter infusion periods (2-4 h). Patients who develop leptomeningeal involvement despite high- dose MTX can be managed with IT chemotherapy such as liposomal cytarabine or MTX or even rituximab. Areas of bulky or symptomatic LMD should probably be treated with radiation therapy as well. Because PCNSL is an uncommon disease, entry into clinical trials must be pursued to advance the state of the art.

[Progress in epidermal stem cells].

PubMed

Wang, Li-Juan; Wang, You-Liang; Yang, Xiao

2010-03-01

Mammalian skin epidermis contains different epidermal stem cell pools which contribute to the homeostasis and repair of skin epithelium. Epidermal stem cells possess two essential features common to all stem cells: self-renewal and differentiation. Disturbing the balance between self-renewal and differentiation of epidermal stem cell often causes tumors or other skin diseases. Epidermal stem cell niches provide a special microenvironment that maintains a balance of stem cell quiescence and activity. This review primarily concentrates on the following points of the epidermal stem cells: the existing evidences, the self-renewal and differentiation, the division pattern, the signal pathways regulating self-renewal and differentiation, and the microenvironment (niche) and macroenvironment maintaining the homeostasis of stem cells.

[Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

PubMed

Liang, Hang; Deng, Xiangyu; Shao, Zengwu

2017-10-01

To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

Amnion-derived stem cells: in quest of clinical applications

PubMed Central

2011-01-01

In the promising field of regenerative medicine, human perinatal stem cells are of great interest as potential stem cells with clinical applications. Perinatal stem cells could be isolated from normally discarded human placentae, which are an ideal cell source in terms of availability, the fewer number of ethical concerns, less DNA damage, and so on. Numerous studies have demonstrated that some of the placenta-derived cells possess stem cell characteristics like pluripotent differentiation ability, particularly in amniotic epithelial (AE) cells. Term human amniotic epithelium contains a relatively large number of stem cell marker-positive cells as an adult stem cell source. In this review, we introduce a model theory of why so many AE cells possess stem cell characteristics. We also describe previous work concerning the therapeutic applications and discuss the pluripotency of the AE cells and potential pitfalls for amnion-derived stem cell research. PMID:21596003

The role of stem cells in aesthetic surgery: fact or fiction?

PubMed

McArdle, Adrian; Senarath-Yapa, Kshemendra; Walmsley, Graham G; Hu, Michael; Atashroo, David A; Tevlin, Ruth; Zielins, Elizabeth; Gurtner, Geoffrey C; Wan, Derrick C; Longaker, Michael T

2014-08-01

Stem cells are attractive candidates for the development of novel therapies, targeting indications that involve functional restoration of defective tissue. Although most stem cell therapies are new and highly experimental, there are clinics around the world that exploit vulnerable patients with the hope of offering supposed stem cell therapies, many of which operate without credible scientific merit, oversight, or other patient protection. The authors review the potential and the drawbacks of incorporation of stem cells in cosmetic procedures. A review of U.S. Food and Drug Administration-approved indications and ongoing clinical trials with adipose stem cells is provided. Furthermore, a "snapshot" analysis of Web sites using the search terms "stem cell therapy" or "stem cell treatment" or "stem cell facelift" was performed. Despite the protective net cast by regulatory agencies such as the U.S. Food and Drug Administration and professional societies such as the American Society of Plastic Surgeons, the authors are witnessing worrying advertisements for procedures such as stem cell face lifts, stem cell breast augmentations, and even stem cell vaginal rejuvenation. The marketing and promotion of stem cell procedures in aesthetic surgery is not adequately supported by clinical evidence in the majority of cases. Stem cells offer tremendous potential, but the marketplace is saturated with unsubstantiated and sometimes fraudulent claims that may place patients at risk. With plastic surgeons at the forefront of stem cell-based regenerative medicine, it is critically important that they provide an example of a rigorous approach to research, data collection, and advertising of stem cell therapies.

Polymer microarray technology for stem cell engineering

PubMed Central

Coyle, Robert; Jia, Jia; Mei, Ying

2015-01-01

Stem cells hold remarkable promise for applications in tissue engineering and disease modeling. During the past decade, significant progress has been made in developing soluble factors (e.g., small molecules and growth factors) to direct stem cells into a desired phenotype. However, the current lack of suitable synthetic materials to regulate stem cell activity has limited the realization of the enormous potential of stem cells. This can be attributed to a large number of materials properties (e.g., chemical structures and physical properties of materials) that can affect stem cell fate. This makes it challenging to design biomaterials to direct stem cell behavior. To address this, polymer microarray technology has been developed to rapidly identify materials for a variety of stem cell applications. In this article, we summarize recent developments in polymer array technology and their applications in stem cell engineering. Statement of significance Stem cells hold remarkable promise for applications in tissue engineering and disease modeling. In the last decade, significant progress has been made in developing chemically defined media to direct stem cells into a desired phenotype. However, the current lack of the suitable synthetic materials to regulate stem cell activities has been limiting the realization of the potential of stem cells. This can be attributed to the number of variables in material properties (e.g., chemical structures and physical properties) that can affect stem cells. Polymer microarray technology has shown to be a powerful tool to rapidly identify materials for a variety of stem cell applications. Here we summarize recent developments in polymer array technology and their applications in stem cell engineering. PMID:26497624

Stem cells in kidney regeneration.

PubMed

Yokote, Shinya; Yokoo, Takashi

2012-01-01

Currently many efforts are being made to apply regenerative medicine to kidney diseases using several types of stem/progenitor cells, such as mesenchymal stem cells, renal stem/progenitor cells, embryonic stem cells and induced pluripotent stem cells. Stem cells have the ability to repair injured organs and ameliorate damaged function. The strategy for kidney tissue repair is the recruitment of stem cells and soluble reparative factors to the kidney to elicit tissue repair and the induction of dedifferentiation of resident renal cells. On the other hand, where renal structure is totally disrupted, absolute kidney organ regeneration is needed to rebuild a whole functional kidney. In this review, we describe current advances in stem cell research for kidney tissue repair and de novo organ regeneration.

Stem Cell Sciences plc.

PubMed

Daniels, Sebnem

2006-09-01

Stem Cell Sciences' core objective is to develop safe and effective stem cell-based therapies for currently incurable diseases. In order to achieve this goal, Stem Cell Sciences recognizes the need for multiple technologies and a globally integrated stem cell initiative. The key challenges for the successful application of stem cells in the clinic is the need for a reproducible supply of pure, fully characterized stem cells that have been grown in suitable conditions for use in the clinic.

Fusion with stem cell makes the hepatocellular carcinoma cells similar to liver tumor-initiating cells.

PubMed

Wang, Ran; Chen, Shuxun; Li, Changxian; Ng, Kevin Tak Pan; Kong, Chi-wing; Cheng, Jinping; Cheng, Shuk Han; Li, Ronald A; Lo, Chung Mau; Man, Kwan; Sun, Dong

2016-02-04

Cell fusion is a fast and highly efficient technique for cells to acquire new properties. The fusion of somatic cells with stem cells can reprogram somatic cells to a pluripotent state. Our research on the fusion of stem cells and cancer cells demonstrates that the fused cells can exhibit stemness and cancer cell-like characteristics. Thus, tumor-initiating cell-like cells are generated. We employed laser-induced single-cell fusion technique to fuse the hepatocellular carcinoma cells and human embryonic stem cells (hESC). Real-time RT-PCR, flow cytometry and in vivo tumorigenicity assay were adopted to identify the gene expression difference. We successfully produced a fused cell line that coalesces the gene expression information of hepatocellular carcinoma cells and stem cells. Experimental results showed that the fused cells expressed cancer and stemness markers as well as exhibited increased resistance to drug treatment and enhanced tumorigenesis. Fusion with stem cells transforms liver cancer cells into tumor initiating-like cells. Results indicate that fusion between cancer cell and stem cell may generate tumor initiating-like cells.

Stem cell-derived vascular endothelial cells and their potential application in regenerative medicine

USDA-ARS?s Scientific Manuscript database

Although a 'vascular stem cell' population has not been identified or generated, vascular endothelial and mural cells (smooth muscle cells and pericytes) can be derived from currently known pluripotent stem cell sources, including human embryonic stem cells and induced pluripotent stem cells. We rev...

Hematopoietic cell differentiation from embryonic and induced pluripotent stem cells

PubMed Central

2013-01-01

Pluripotent stem cells, both embryonic stem cells and induced pluripotent stem cells, are undifferentiated cells that can self-renew and potentially differentiate into all hematopoietic lineages, such as hematopoietic stem cells (HSCs), hematopoietic progenitor cells and mature hematopoietic cells in the presence of a suitable culture system. Establishment of pluripotent stem cells provides a comprehensive model to study early hematopoietic development and has emerged as a powerful research tool to explore regenerative medicine. Nowadays, HSC transplantation and hematopoietic cell transfusion have successfully cured some patients, especially in malignant hematological diseases. Owing to a shortage of donors and a limited number of the cells, hematopoietic cell induction from pluripotent stem cells has been regarded as an alternative source of HSCs and mature hematopoietic cells for intended therapeutic purposes. Pluripotent stem cells are therefore extensively utilized to facilitate better understanding in hematopoietic development by recapitulating embryonic development in vivo, in which efficient strategies can be easily designed and deployed for the generation of hematopoietic lineages in vitro. We hereby review the current progress of hematopoietic cell induction from embryonic stem/induced pluripotent stem cells. PMID:23796405

Solution formulation development of a VEGF inhibitor for intravitreal injection.

PubMed

Marra, Michelle T; Khamphavong, Penney; Wisniecki, Peter; Gukasyan, Hovhannes J; Sueda, Katsuhiko

2011-03-01

PF-00337210 is a potent, selective small molecule inhibitor of VEGFRs and has been under consideration for the treatment of age-related macular degeneration. An ophthalmic solution formulation intended for intravitreal injection was developed. This formulation was designed to maximize drug properties such that the formulation would precipitate upon injection into the vitreous for sustained delivery. As a parenteral formulation with additional constraints dictated by this specialized delivery route, multiple features were balanced in order to develop a successful formulation. Some of these considerations included low dosing volumes (≤0.1 mL), a limited repertoire of safe excipients for intravitreal injection, and the unique physical chemical properties of the drug. The aqueous solubility as a function of pH was characterized, buffer stressing studies to select the minimal amount of buffer were conducted, and both chemical and physical stability studies were executed. The selected formulation consisted of an isotonic solution comprised of PF-00337210 free base in a citrate-buffered vehicle containing NaCl for tonicity. The highest strength for regulatory toxicology studies was 60 mg/mL. The selected formulation exhibited sufficient chemical stability upon storage with no precipitation, and acceptable potency and recovery through an intravitreal dosing syringe. Formulation performance was simulated by precipitation experiments using extracted vitreous humor. In simulated injection experiments, PF-00337210 solutions reproducibly precipitated upon introduction to the vitreous so that a depot was formed. To our knowledge, this is the first time that a nonpolymeric in situ-forming depot formulation has been developed for intravitreal delivery, with the active ingredient as the precipitating agent. © 2011 American Association of Pharmaceutical Scientists

Humoral Immune Response After Intravitreal But Not After Subretinal AAV8 in Primates and Patients.

PubMed

Reichel, Felix F; Peters, Tobias; Wilhelm, Barbara; Biel, Martin; Ueffing, Marius; Wissinger, Bernd; Bartz-Schmidt, Karl U; Klein, Reinhild; Michalakis, Stylianos; Fischer, M Dominik

2018-04-01

To study longitudinal changes of anti-drug antibody (ADA) titers to recombinant adeno-associated virus serotype 8 (rAAV8) capsid epitopes in nonhuman primates (NHP) and patients. Three groups of six NHP each received subretinal injections (high dose: 1 × 1012 vector genomes [vg], low dose: 1 × 1011 vg, or vehicle only). Four additional animals received intravitreal injections of the high dose (1 × 1012 vg). Three patients received 1 × 1010 vg as subretinal injections. ELISA quantified ADA levels at baseline and 1, 2, 3, 7, 28, and 90 days after surgery in NHP and at baseline and 1, 3, and 6 months after surgery in patients. Two out of 22 animals lacked ADA titers at baseline and developed low ADA titers toward the end of the study. Titers in the low-dose group stayed constant, while two of six animals from the high-dose group developed titers that rose beyond the range of the assay. All animals from the intravitreal control group showed a rise in ADA titer by day 7 that peaked at day 28. Preliminary data from the clinical trial (NCT02610582) show no humoral immune response in patients following subretinal delivery of 1 × 1010 vg. No significant induction of ADA occurred in NHP when mimicking the clinical scenario of subretinal delivery with a clinical-grade rAAV8 and concomitant immunosuppression. Likewise, clinical data showed no humoral immune response in patients. In contrast, intravitreal delivery was associated with a substantial humoral immune response. Subretinal delivery might be superior to an intravitreal application regarding immunologic aspects.

Evolution of Choroidal Neovascular Membrane in Best Disease after Single Intravitreal Bevacizumab. Case Report.

PubMed

Celea, Christiana; Pop, Mihai; Avidis-Zamfiroiu, Nicoleta; Celea, Cristian

2015-03-01

Best's disease is a hereditary form of macular dystrophy that starts in childhood and progresses until visual symptoms occur. In evolution it can be complicated with choroidal neovascularization, condition very rare in children. We report an important visual improvement in a 8-year-old caucasian girl after successful treatment with one intravitreal bevacizumab injection. There are few cases reported in literature (1-7), and the patient presented here have important particularities: one of the youngest children ever-mentioned with this complication, the third-member of her family with this disease and the first patient who didn't receive a second intravitreal bevacizumab at six weeks after first treatment, even though BCVA was lower than expected. The girl accused decrease of vision in the RE for the past 3-4 months. BCVA at presentation was 1/10. After 6 weeks from the intravitreal treatment, BCVA improved, but not very satisfactory (5/10). Because fundus and OCT aspects were encouraging, we waited another 4 weeks before the second injection. BCVA doubled in this period (8/10). Visual acuity, fundus and OCT aspects stabilized for 18 months of follow-up. We note that choroidal neovascular membrane associated with Best's disease can appear at such young children, this fact being very important in the phase of diagnosis, when the clinician should also take in consideration this possibility. Another important idea underlined here is the long-term efficacy of a single intravitreal anti-VEGF injection and also the no-need for imminent, fast re-treatment when the fundus and OCT aspects are encouraging through the follow-up.

Ischemic index changes in diabetic retinopathy after intravitreal dexamethasone implant using ultra-widefield fluorescein angiography: a pilot study.

PubMed

Querques, Lea; Parravano, Mariacristina; Sacconi, Riccardo; Rabiolo, Alessandro; Bandello, Francesco; Querques, Giuseppe

2017-08-01

To investigate the effect of dexamethasone intravitreal implant on peripheral ischemia in patients affected by diabetic macular edema (DME). Patients with treatment-naïve diabetic retinopathy (DR) undergoing intravitreal dexamethasone implant for DME between October 2015 and March 2017 were enrolled. Patients underwent a comprehensive ocular examination at baseline (<2 weeks before treatment) and 10 ± 2 weeks after dexamethasone implant including best-corrected visual acuity (BCVA), intraocular pressure, optical coherence tomography, ultra-widefield (UWF) retinography and UWF fluorescein angiography (UWFA). Nine eyes of seven consecutive patients (five males; mean age 66.4 ± 6.7 years) were enrolled. Mean duration of DR was 12.3 ± 8.4 years. Mean interval between UWFA acquisitions was 12.1 ± 2.1 weeks, and the mean interval between intravitreal injection and UWFA acquisition was 11.0 ± 1.6 weeks. Mean pre- and post-injection BCVA was 0.30 ± 0.20 and 0.21 ± 0.14 logMAR (p = 0.06), respectively. Mean pre- and post-injection central macular thickness was 449.8 ± 92.5 and 356.3 ± 52.4 μm (p = 0.03), respectively. Mean pre- and post-injection ischemic index was 24.0 ± 25.0 and 9.8 ± 12.1% (p = 0.0427), respectively. Intravitreal dexamethasone implant reduces peripheral retina ischemia in patients with DR.

Safety of intravitreal quinupristin/dalfopristin in an animal model.

PubMed

Giordano, Veronica E; Hernandez-Da Mota, Sergio E; Adabache-Guel, Tania N; Castillejos-Chevez, Armando; Corredor-Casas, Sonia; Salinas-Longoria, Samantha M; Romero-Vera, Rafael; Jimenez-Sierra, Juan M; Guerrero-Naranjo, Jose L; Morales-Canton, Virgilio

2016-01-01

To determine whether different intravitreal doses of quinupristin/dalfopristin lead to electroretinographic or histological changes in the rabbit retina over one month period after injection. Eighteen New Zealand white rabbits were divided into three treatment groups (groups 1 to 3) and different intravitreal doses of quinupristin/dalfopristin were tested in each group. The right eye was injected with the drug and the left eye received intravitreal injection of 5% dextrose water and served as control eye. The doses delivered to each group were 0.1 mg/0.1 mL, 1 mg/0.1 mL and 10 mg/0.1 mL. Simultaneous, bilateral, dark-adapted electroretinography and clinical images of both eyes were obtained in all groups before injection (baseline) and after 7, 14, 21 and 28d, followed by enucleation for histological examination. Subjects in the group 1 showed no signs of toxicity in the electroretinogram when compared with groups 2 and 3 (Kruskall-Wallis test, P=0.000). By day 7, no electrical response to light stimuli was recorded in the treated eyes in groups 2 and 3, consistent with severe damage due to retinal toxicity. Light microscopy revealed no significant histopathological changes in the group 1, while rabbits in groups 2 and 3 had signs of granulomatous inflammation in most cases. Intravitreal 0.1 mg/0.1 mL doses of quinupristin/dalfopristin do not lead to electroretinographic or histological signs of retinal toxicity compared with 1 mg/0.1 mL and 10 mg/0.1 mL in this rabbit model.

Randomized trial evaluating short-term effects of intravitreal ranibizumab or triamcinolone acetonide on macular edema after focal/grid laser for diabetic macular edema in eyes also receiving panretinal photocoagulation.

PubMed

Googe, Joseph; Brucker, Alexander J; Bressler, Neil M; Qin, Haijing; Aiello, Lloyd P; Antoszyk, Andrew; Beck, Roy W; Bressler, Susan B; Ferris, Frederick L; Glassman, Adam R; Marcus, Dennis; Stockdale, Cynthia R

2011-06-01

To evaluate 14-week effects of intravitreal ranibizumab or triamcinolone in eyes receiving focal/grid laser for diabetic macular edema and panretinal photocoagulation. Three hundred and forty-five eyes with a visual acuity of 20/320 or better, center-involved diabetic macular edema receiving focal/grid laser, and diabetic retinopathy receiving prompt panretinal photocoagulation were randomly assigned to sham (n = 123), 0.5-mg ranibizumab (n = 113) at baseline and 4 weeks, and 4-mg triamcinolone at baseline and sham at 4 weeks (n = 109). Treatment was at investigator discretion from 14 weeks to 56 weeks. Mean changes (±SD) in visual acuity letter score from baseline were significantly better in the ranibizumab (+1 ± 11; P < 0.001) and triamcinolone (+2 ± 11; P < 0.001) groups compared with those in the sham group (-4 ± 14) at the 14-week visit, mirroring retinal thickening results. These differences were not maintained when study participants were followed for 56 weeks for safety outcomes. One eye (0.9%; 95% confidence interval, 0.02%-4.7%) developed endophthalmitis after receiving ranibizumab. Cerebrovascular/cardiovascular events occurred in 4%, 7%, and 3% of the sham, ranibizumab, and triamcinolone groups, respectively. The addition of 1 intravitreal triamcinolone injection or 2 intravitreal ranibizumab injections in eyes receiving focal/grid laser for diabetic macular edema and panretinal photocoagulation is associated with better visual acuity and decreased macular edema by 14 weeks. Whether continued long-term intravitreal treatment is beneficial cannot be determined from this study.

SHORT-TERM SAFETY PROFILE OF INTRAVITREAL ZIV-AFLIBERCEPT.

PubMed

Chhablani, Jay; Narayanan, Raja; Mathai, Annie; Yogi, Rohit; Stewart, Michael

2016-06-01

To evaluate the safety of intravitreal ziv-aflibercept (Zaltrap) in the treatment choroidal neovascularization secondary to age-related macular degeneration. Eligible eyes with choroidal neovascularization secondary to age-related macular degeneration each received a single intravitreal injection of ziv-aflibercept. Comprehensive ophthalmic examinations and detailed systemic evaluations were performed at baseline and Days 1, 7, and 30 after injection, and International Society for Clinical Electrophysiology of Vision standard electroretinography was performed at baseline and Day 30. Primary outcome measures were safety parameters that included signs of clinical and electroretinographic toxicity. Secondary outcome measures included changes in best-corrected visual acuity and central subfield thickness. Twelve eyes of 12 patients were treated. None of the patients complained of blurred vision, ocular pain, or bulbar injection at any of the follow-up visits, nor was intraocular inflammation noted. There were no significant differences in implicit times, "a" and "b" wave amplitudes, or b/a ratios at 1 month when compared with baseline (P = 0.4). None of the patients experienced serious ocular or systemic adverse events. Mean best-corrected visual acuity improved only slightly at 30 days (LogMAR 0.45 ± 0.31 [Snellen equivalent: 20/60]) compared with baseline (LogMAR 0.37 ± 0.24 [Snellen equivalent: 20/50]; P = 0.51). Single intravitreal injections of ziv-aflibercept into eyes with neovascular age-related macular degeneration appear to be safe through 1 month. Ziv-aflibercept could become a safe, low-cost therapy for macular diseases in developing countries and in those where intravitreal aflibercept (Eylea) is not available.

An Outbreak of Streptococcus Endophthalmitis after Intravitreal Injection of Bevacizumab

PubMed Central

Goldberg, Roger A.; Flynn, Harry W.; Isom, Ryan F.; Miller, Darlene; Gonzalez, Serafin

2011-01-01

Purpose To report a series of patients with Streptococcus endophthalmitis after injection with intravitreal bevacizumab prepared by the same compounding pharmacy. Design Non-comparative consecutive case series. Methods Medical records and microbiology results of patients who presented with endophthalmitis after injection with intravitreal bevacizumab between July 5 and July 8, 2011, were reviewed. Results Twelve patients were identified with endophthalmitis, presenting 1-6 days after receiving an intravitreal injection of bevacizumab. The injections occurred at four different locations in South Florida. All patients received bevacizumab prepared by the same compounding pharmacy. None of the infections originated at the Bascom Palmer Eye Institute, Miami, FL, although nine patients presented to its tertiary-care ophthalmic emergency room for treatment, and three additional patients were seen in consultation. All patients were treated initially with a vitreous tap and injection; eight patients subsequently received a vitrectomy. Microbiology cultures for ten patients were positive for Streptococcus mitis/oralis. Seven unused syringes of bevacizumab prepared by the compounding pharmacy at the same time as those prepared for the affected patients also were positive for S. mitis/oralis. After four months of follow-up, all but one patient had count-fingers or worse visual acuity, and three required evisceration or enucleation. Local, state and federal health department officials have been investigating the source of the contamination. Conclusions In this outbreak of endophthalmitis after intravitreal bevacizumab injection, Streptococcus mitis/oralis was cultured from the majority of patients and from all unused syringes. Visual outcomes were generally poor. The most likely cause of this outbreak was contamination during syringe preparation by the compounding pharmacy. PMID:22264943

A randomised controlled trial of ranibizumab with and without ketorolac eyedrops for exudative age-related macular degeneration.

PubMed

Russo, Andrea; Costagliola, Ciro; Delcassi, Luisa; Romano, Mario R; Semeraro, Francesco

2013-10-01

To evaluate whether ketorolac eyedrops and ranibizumab intravitreal injections would provide additional benefit over ranibizumab alone in the treatment of choroidal neovascularisation (CNV). This was a pilot study of eyes with new-onset CNV. A total of 56 patients were enrolled consecutively and randomised in a 1:1 ratio to receive combination treatment with intravitreal ranibizumab and topical ketorolac (group 1) or ranibizumab alone (group 2). All patients received monthly 0.5-mg ranibizumab intravitreal injections for 3 months, after which monthly injections were administered in accordance with the standard of care. Group 1 patients also self-administered one drop of ketorolac three times a day for 6 months. All patients were followed up for 6 months. At 6 months, both groups showed a significant improvement in best-corrected visual acuity (both, p<0.001). The two treatments did not show significant differences in terms of the number of ranibizumab injections required. However, the mean 6-month change in central macular thickness (CMT) in the combination group was -124 µm (-29.7%; p<0.001), while in the ranibizumab-only group, the change was -86.9 µm (-19.5%; p=0.001); thus, the combination treatment resulted in a greater reduction (p=0.003). The combination treatment had no adverse effects. This pilot study is the first to prospectively investigate the efficacy and safety of a combination of 0.45% ketorolac eyedrops three times a day and intravitreal ranibizumab injections in patients with CNV, and suggests that topical ketorolac supplements the activity of intravitreal ranibizumab in reducing CMT in CNV.

Early Retinal and Choroidal Coat Thickness Changes After Intravitreal Dexamethasone Implant Injection for Diabetic Macular Edema.

PubMed

Horozoğlu, Fatih; Sever, Özkan

2018-06-05

Intravitreal steroid injection is one of the treatment choices in diabetic macular edema (DME). Dexamethasone (Dx) implant is the most novel form of intravitreal steroid therapy. Macular thickness improvement is well known effect of Dx implant however; subfoveal choroidal coat thickness (SFCT) changes need to be investigated. To evaluate the early central macular thickness (CMT) and SFCT alterations after single dose dexamethasone implant injection in DME. Retrospective cross-sectional study. We identified 29 patients with DME (29 eyes) who underwent optical coherence tomography (OCT) and fundus fluoroscein angiography (FFA). All patients received a single dose intravitreal Dx implant and were followed for CMT and SFCT alterations for the post-injection first hour, first day, first week, first month and third month. The preoperative mean CMT and SFCT measurements were 592.3±122.3 (412-879) μm and 264.8±53.7 (165-397) μm, respectively. CMT measurements significantly decreased from the first hour (p<0.050) and kept decreasing till 3 month (p<0.001); while SFCT decrement was just significant at the first day (p<0.05). When we compared the decrease in SFCT and CMT, 1 hour was similar, however not significant, 1.5% SFCT and 5% CMT decrease was, respectively (p>0.050). CMT decrease rate was significantly higher than SFCT at 1 day, 1 week, 1 month and 3 month (p<0.001). Intravitreal Dx implant has got a meaningful effect on CMT in patients with DME while SFCT decreases significantly at first hour and first day.

Alternating Bi-Weekly Intravitreal Ranibizumab and Bevacizumab for Refractory Neovascular Age-Related Macular Degeneration with Pigment Epithelial Detachment.

PubMed

Witkin, Andre J; Rayess, Nadim; Garg, Sunir J; Maguire, Joseph I; Storey, Philip; Kaiser, Richard S; Hsu, Jason; Vander, James F; Ho, Allen C

2017-01-01

To describe visual and anatomical outcomes following bi-weekly intravitreal ranibizumab/bevacizumab injections in eyes with refractory neovascular age-related macular degeneration (AMD) and pigment epithelial detachment (PED). Retrospective, consecutive, interventional case series. Eighteen patients diagnosed with neovascular AMD that were refractory to anti-VEGF therapy and received alternating biweekly ranibizumab/bevacizumab injections were included. Patients with neovascular AMD and PED that were refractory to at least 11 monthly ranibizumab or bevacizumab injections were included in this study at a large, single retina practice. Following inclusion, patients received four bi-weekly alternating ranibizumab/bevacizumab intravitreal injections. After completing a course of four bi-weekly injections, patients were treated with variable regimens of intravitreal anti-vascular endothelial growth factor (VEGF) therapy. The primary outcomes of the study included change in visual acuity (VA) and central foveal thickness (CFT) at eight weeks follow-up. Study eyes had previously received a mean of 22 intravitreal anti-VEGF injections. At enrollment, mean VA was 20/95 and mean CFT was 455 µm. After four bi-weekly anti-VEGF injections, mean VA improved to 20/65 (p < 0.001), and mean CFT decreased to 387 µm (p = 0.029). In patients with PED, there was a mean 27.9% reduction in height (p = 0.046) at eight weeks' follow-up. Four injections of bi-weekly alternating ranibizumab/bevacizumab improved visual acuity and reduced macular thickness in a number of patients with refractory neovascular AMD and PED.

Estimated cases of blindness and visual impairment from neovascular age-related macular degeneration avoided in Australia by ranibizumab treatment.

PubMed

Mitchell, Paul; Bressler, Neil; Doan, Quan V; Dolan, Chantal; Ferreira, Alberto; Osborne, Aaron; Rochtchina, Elena; Danese, Mark; Colman, Shoshana; Wong, Tien Y

2014-01-01

Intravitreal injections of anti-vascular endothelial growth factor agents, such as ranibizumab, have significantly improved the management of neovascular age-related macular degeneration. This study used patient-level simulation modelling to estimate the number of individuals in Australia who would have been likely to avoid legal blindness or visual impairment due to neovascular age-related macular degeneration over a 2-year period as a result of intravitreal ranibizumab injections. The modelling approach used existing data for the incidence of neovascular age-related macular degeneration in Australia and outcomes from ranibizumab trials. Blindness and visual impairment were defined as visual acuity in the better-seeing eye of worse than 6/60 or 6/12, respectively. In 2010, 14,634 individuals in Australia were estimated to develop neovascular age-related macular degeneration who would be eligible for ranibizumab therapy. Without treatment, 2246 individuals would become legally blind over 2 years. Monthly 0.5 mg intravitreal ranibizumab would reduce incident blindness by 72% (95% simulation interval, 70-74%). Ranibizumab given as needed would reduce incident blindness by 68% (64-71%). Without treatment, 4846 individuals would become visually impaired over 2 years; this proportion would be reduced by 37% (34-39%) with monthly intravitreal ranibizumab, and by 28% (23-33%) with ranibizumab given as needed. These data suggest that intravitreal injections of ranibizumab, given either monthly or as needed, can substantially lower the number of cases of blindness and visual impairment over 2 years after the diagnosis of neovascular age-related macular degeneration.

Stem Cell Basics

MedlinePlus

... Tips Info Center Research Topics Federal Policy Glossary Stem Cell Information General Information Clinical Trials Funding Information Current ... Basics » Stem Cell Basics I. Back to top Stem Cell Basics I. Introduction: What are stem cells, and ...

TOPICAL REVIEW: Stem cells engineering for cell-based therapy

NASA Astrophysics Data System (ADS)

Taupin, Philippe

2007-09-01

Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

From Banking to International Governance: Fostering Innovation in Stem Cell Research

PubMed Central

Isasi, Rosario; Knoppers, Bartha M.

2011-01-01

Stem cell banks are increasingly recognized as an essential resource of biological materials for both basic and translational stem cell research. By providing transnational access to quality controlled and ethically sourced stem cell lines, stem cell banks seek to foster international collaboration and innovation. However, given that national stem cell banks operate under different policy, regulatory and commercial frameworks, the transnational sharing of stem cell materials and data can be complicating. This paper will provide an overview of the most pressing challenges regarding the governance of stem cell banks, and the difficulties in designing regulatory and commercial frameworks that foster stem cell research. Moreover, the paper will shed light on the numerous international initiatives that have arisen to help harmonize and standardize stem cell banking and research processes to overcome such challenges. PMID:21904557

Stem Cells Transplantation in the Treatment of Patients with Liver Failure.

PubMed

Tao, Ya-Chao; Wang, Meng-Lan; Chen, En-Qiang; Tang, Hong

2018-02-23

Liver failure is a life-threatening liver disease encompassing severe acute deterioration of liver function. Emergency liver transplantation is the only curative treatment for liver failure, but is restricted by the severe shortage of organ donors. Stem cell, including embroyonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, hematopoietic stem cells and hepatic progenitor cells, have capacity to proliferate and differentiate and could be used in a variety of liver diseases including hereditary liver diseases, cirrhosis and liver failure. We summarized the basic experimental and clinical advances of stem cell transplantation in liver failure treatment, and also discussed the advantages and disadvantage of different stem cells subtype in this field, aiming to provide a perspective on the stem cell-based therapy for liver failure. Stem cells, especially mesenchymal stem cells (mainly low immunogenicity and paracrine characteristics) and induced pluripotent stem cells (generation of desired cell type from somatic cell), are feasible candidates for cell therapy in the treatment of liver failure, but there are some drawbacks remaining to be resolved, such as low engraftment, cryotpreservation methods and tumorigenesis. Stem cell transplantation is a promising but challenging strategy and paves a new way for curing liver failure. But more efforts need to be made to overcome problems before this new strategy could be safely and effectively applied to humans. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Recent Progress in Stem Cell Modification for Cardiac Regeneration

PubMed Central

Voronina, Natalia; Steinhoff, Gustav

2018-01-01

During the past decades, stem cell-based therapy has acquired a promising role in regenerative medicine. The application of novel cell therapeutics for the treatment of cardiovascular diseases could potentially achieve the ambitious aim of effective cardiac regeneration. Despite the highly positive results from preclinical studies, data from phase I/II clinical trials are inconsistent and the improvement of cardiac remodeling and heart performance was found to be quite limited. The major issues which cardiac stem cell therapy is facing include inefficient cell delivery to the site of injury, accompanied by low cell retention and weak effectiveness of remaining stem cells in tissue regeneration. According to preclinical and clinical studies, various stem cells (adult stem cells, embryonic stem cells, and induced pluripotent stem cells) represent the most promising cell types so far. Beside the selection of the appropriate cell type, researchers have developed several strategies to produce “second-generation” stem cell products with improved regenerative capacity. Genetic and nongenetic modifications, chemical and physical preconditioning, and the application of biomaterials were found to significantly enhance the regenerative capacity of transplanted stem cells. In this review, we will give an overview of the recent developments in stem cell engineering with the goal to facilitate stem cell delivery and to promote their cardiac regenerative activity. PMID:29535769

Eat, breathe, ROS: controlling stem cell fate through metabolism.

PubMed

Kubli, Dieter A; Sussman, Mark A

2017-05-01

Research reveals cardiac regeneration exists at levels previously deemed unattainable. Clinical trials using stem cells demonstrate promising cardiomyogenic and regenerative potential but insufficient contractile recovery. Incomplete understanding of the biology of administered cells likely contributes to inconsistent patient outcomes. Metabolism is a core component of many well-characterized stem cell types, and metabolic changes fundamentally alter stem cell fate from self-renewal to lineage commitment, and vice versa. However, the metabolism of stem cells currently studied for cardiac regeneration remains incompletely understood. Areas covered: Key metabolic features of stem cells are reviewed and unique stem cell metabolic characteristics are discussed. Metabolic changes altering stem cell fate are considered from quiescence and self-renewal to lineage commitment. Key metabolic concepts are applied toward examining cardiac regeneration through stem cell-based approaches, and clinical implications of current cell therapies are evaluated to identify potential areas of improvement. Expert commentary: The metabolism and biology of stem cells used for cardiac therapy remain poorly characterized. A growing appreciation for the fundamental relationship between stem cell functionality and metabolic phenotype is developing. Future studies unraveling links between cardiac stem cell metabolism and regenerative potential may considerably improve treatment strategies and therapeutic outcomes.

Eat, breathe, ROS: controlling stem cell fate through metabolism

PubMed Central

Kubli, Dieter A.; Sussman, Mark A.

2017-01-01

Introduction Research reveals cardiac regeneration exists at levels previously deemed unattainable. Clinical trials using stem cells demonstrate promising cardiomyogenic and regenerative potential but insufficient contractile recovery. Incomplete understanding of the biology of administered cells likely contributes to inconsistent patient outcomes. Metabolism is a core component of many well-characterized stem cell types, and metabolic changes fundamentally alter stem cell fate from self-renewal to lineage commitment, and vice versa. However, the metabolism of stem cells currently studied for cardiac regeneration remains incompletely understood. Areas covered Key metabolic features of stem cells are reviewed and unique stem cell metabolic characteristics are discussed. Metabolic changes altering stem cell fate are considered from quiescence and self-renewal to lineage commitment. Key metabolic concepts are applied toward examining cardiac regeneration through stem cell-based approaches, and clinical implications of current cell therapies are evaluated to identify potential areas of improvement. Expert commentary The metabolism and biology of stem cells used for cardiac therapy remain poorly characterized. A growing appreciation for the fundamental relationship between stem cell functionality and metabolic phenotype is developing. Future studies unraveling links between cardiac stem cell metabolism and regenerative potential may considerably improve treatment strategies and therapeutic outcomes. PMID:28406333

Therapeutic strategies involving uterine stem cells in reproductive medicine.

PubMed

Simoni, Michael; Taylor, Hugh S

2018-06-01

The current review provides an update on recent advances in stem cell biology relevant to female reproduction. Stem cells are undifferentiated cells that often serve as a reservoir of cells to regenerate tissue in settings or injury or cell loss. The endometrium has progenitor stem cells that can replace all of the endometrium during each menstrual cycle. In addition, multipotent endometrial cells replace these progenitor cells when depleted. Recruitment of stem cells from outside of the uterus occurs in setting of increased demand such as ischemia or injury. Bone marrow-derived multipotent stem cells are recruited to the uterus by estrogen or injury-induced expression of the chemokine CXCL12. In the setting of overwhelming injury, especially in the setting of low estrogen levels, there may be insufficient stem cell recruitment to adequately repair the uterus resulting in conditions such as Asherman syndrome or other endometrial defects. In contrast, excessive recruitment of stem cells underlies endometriosis. Enhanced understanding of stem-cell mobilization, recruitment, and engraftment has created the possibility of improved therapy for endometrial defects and endometriosis through enhanced manipulation of stem-cell trafficking. Further, the normal endometrium is a rich source of multipotent stem cells that can be used for numerous applications in regenerative medicine beyond reproduction. A better understanding of reproductive stem-cell biology may allow improved treatment of endometrial disease such as Asherman syndrome and other endometrial receptivity defects. Inhibiting stem-cell mobilization may also be helpful in endometriosis therapy. Finally, endometrial derived multipotent stem cells may play a crucial role in cell therapy for regenerative medicine.

Gene screening of Wharton's jelly derived stem cells.

PubMed

Mechiche Alami, S; Velard, F; Draux, F; Siu Paredes, F; Josse, J; Lemaire, F; Gangloff, S C; Graesslin, O; Laurent-Maquin, D; Kerdjoudj, H

2014-01-01

Stem cells are the most powerful candidate for the treatment of various diseases. Suitable stem cell source should be harvested with minimal invasive procedure, found in great quantity, and transplanted with no risk of immune response and tumor formation. Fetal derived stem cells have been introduced as an excellent alternative to adult and embryonic stem cells use, but unfortunately, their degree of "stemness" and molecular characterization is still unclear. Several studies have been performed deciphering whether fetal stem cells meet the needs of regenerative medicine. We believe that a transcriptomic screening of Wharton's jelly stem cells will bring insights on cell population features.

Intravitreal Steroids for the Treatment of Retinal Diseases

PubMed Central

Veritti, Daniele; Boscia, Francesco

2014-01-01

Diabetic macular edema (DME), pseudophakic cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO), and uveitis are ocular conditions related to severe visual impairment worldwide. Corticosteroids have been widely used in the treatment of these retinal diseases, due to their well-known antiangiogenic, antiedematous, and anti-inflammatory properties. Intravitreal steroids have emerged as novel and essential tools in the ophthalmologist's armamentarium, allowing for maximization of drug efficacy and limited risk of systemic side effects. Recent advances in ocular drug delivery methods led to the development of intraocular implants, which help to provide prolonged treatment with controlled drug release. Moreover, they may add some potential advantages over traditional intraocular injections by delivering certain rates of drug directly to the site of action, amplifying the drug's half-life, contributing in the minimization of peak plasma levels of the drug, and avoiding the side effects associated with repeated intravitreal injections. The purpose of this review is to provide an update on the use of intravitreal steroids as a treatment option for a variety of retinal diseases and to review the current literature considering their properties, safety, and adverse events. PMID:24526927

INTRAOCULAR LENS POSITION IN COMBINED PHACOEMULSIFICATION AND VITREORETINAL SURGERY.

PubMed

Ozates, Serdar; Kiziltoprak, Hasan; Koc, Mustafa; Uzel, Mehmet Murat; Teke, Mehmet Yasin

2017-10-09

To assess the decentration and angle of tilt of the intraocular lens (IOL) according to the intravitreal tamponade types used in combined phacoemulsification and vitreoretinal surgery. This prospective and randomized clinical study involved 73 eyes of 69 patients who underwent combined vitreoretinal surgery. Eyes with intravitreal tamponades formed the study group and eyes without intravitreal tamponades formed the control group. The study group was further divided into silicone oil and gas tamponade subgroups. Cross-sectional IOL images were captured using a Pentacam HR (Oculus, Germany) and tilt and decentration were calculated with Adobe Photoshop software (Adobe, San Jose, CA). The mean angle of tilt and decentration at the vertical meridian were significantly higher in both tamponade groups than in the control group (P < 0.05 for all). No significant difference was observed among the groups regarding IOL position parameters at the horizontal meridian (P > 0.05). When comparing the silicone oil and gas tamponade subgroups, no significant differences were noted on the position of IOL at both meridians (P > 0.05 for all). Intravitreal tamponades have an important effect on the position of IOL in combined vitreoretinal surgery. Silicone oil and gas tamponades may induce postoperative tilt and decentration of one-piece acrylic IOLs.

Successful treatment of toxoplasmosis-associated choroidal neovascular lesions with bevacizumab and antiparasitic therapy.

PubMed

Lin, Chun-Ju; Chen, San-Ni; Hwang, Jiunn-Feng; Hu, Pei-Shin

2011-01-01

To report the effects of oral trimethoprim/sulfamethoxazole and intravitreal bevacizumab injection in the treatment of ocular toxoplasmosis-associated choroidal neovascular lesions (CNV). This was a noncomparative, nonrandomized, consecutive case series. All eyes with ocular toxoplasmosis-associated CNV received one intravitreal bevacizumab injection under the coverage of oral trimethoprim/sulfamethoxazole. The changes in best-corrected visual acuity were recorded. Serial fundus photography, fluorescein angiography, optical coherence tomography, and indocyanine green angiography were performed to measure the treatment efficacy. Three eyes of two patients with a history of ocular toxoplasmosis had active CNV demonstrated by fluorescein angiography and optical coherence tomography. Each was treated with oral trimethoprim/sulfamethoxazole and one intravitreal bevacizumab injection. Best-corrected visual acuity, fundus photographs, fluorescein angiography, optical coherence tomography, and indocyanine green angiography all showed favorable results. No ocular or systemic complications were noted. In all three eyes, the CNV subsided and vision improved. Oral trimethoprim/sulfamethoxazole is an effective and less expensive antibiotic against Toxoplasma gondii. Intravitreal bevacizumab injection appears to be a well-tolerated treatment for toxoplasmosis-associated CNV and has the potential as an adjuvant therapy to improve final vision. More cases and further studies are required.

Intravitreal Bevacizumab (Avastin) for Diabetic Retinopathy: The 2010 GLADAOF Lecture

PubMed Central

Arevalo, J. Fernando; Sanchez, Juan G.; Lasave, Andres F.; Wu, Lihteh; Maia, Mauricio; Bonafonte, Sergio; Brito, Miguel; Alezzandrini, Arturo A.; Restrepo, Natalia; Berrocal, Maria H.; Saravia, Mario; Farah, Michel Eid; Fromow-Guerra, Jans; Morales-Canton, Virgilio

2011-01-01

This paper demonstrates multiple benefits of intravitreal bevacizumab (IVB) on diabetic retinopathy (DR) including diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) at 24 months of followup. This is a retrospective multicenter interventional comparative case series of intravitreal injections of 1.25 or 2.5 mg of bevacizumab for DME, PDR without tractional retinal detachment (TRD), and patients who experienced the development or progression of TRD after an intravitreal injection of 1.25 or 2.5 mg of bevacizumab before vitrectomy for the management of PDR. The results indicate that IVB injections may have a beneficial effect on macular thickness and visual acuity (VA) in diffuse DME. Therefore, in the future this new therapy could complement focal/grid laser photocoagulation in DME. In PDR, this new option could be an adjuvant agent to panretina photocoagulation so that more selective therapy may be applied. Finally, TRD in PDR may occur or progress after IVB used as an adjuvant to vitrectomy. Surgery should be performed 4 days after IVB. Most patients had poorly controlled diabetes mellitus associated with elevated HbA1c, insulin administration, PDR refractory to panretinal photocoagulation, and longer time between IVB and vitrectomy. PMID:21584260

Progressive outer retinal necrosis in the era of highly active antiretroviral therapy: successful management with intravitreal injections and monitoring with quantitative PCR.

PubMed

Yin, Philip D; Kurup, Shree K; Fischer, Steven H; Rhee, Henry H; Byrnes, Gordon A; Levy-Clarke, Grace A; Buggage, Ronald R; Nussenblatt, Robert B; Mican, JoAnn M; Wright, Mary E

2007-03-01

Progressive outer retinal necrosis (PORN) is an ocular disease in individuals with AIDS and is associated with substantial morbidity. The optimal management of PORN and its clinical course in the HAART era is unclear. We report a case of successfully managed PORN that provides insight into the monitoring and treatment of this disease. Intravitreal injections and intravenous therapy targeted towards varicella zoster virus (VZV) were used to treat PORN. HAART was initiated for HIV-1 therapy. Serial PCR for VZV was performed on aqueous humor to monitor the clinical course. The presence of VZV DNA from aqueous humor correlated with clinical exacerbations of disease. Initiation of twice weekly intravitreal injections with dual antiviral drugs appeared to be an important therapeutic intervention that resulted in remission of PORN. Secondary prophylaxis against VZV was successfully withdrawn after HAART induced partial immune recovery. In addition to aggressive therapy with intravitreal injections, HAART and quantitative measurements of VZV DNA from aqueous humor have important roles in the management of PORN. A multidisciplinary approach involving specialists in infectious diseases, ophthalmology, and clinical microbiology will improve the chances for successful long-term outcomes.

Intravitreal bevacizumab injections for treatment of central retinal vein occlusion: six-month results of a prospective trial.

PubMed

Priglinger, Siegfried G; Wolf, Armin H; Kreutzer, Thomas C; Kook, Daniel; Hofer, Anja; Strauss, Rupert W; Alge, Claudia S; Kunze, Christian; Haritoglou, Christos; Kampik, Anselm

2007-10-01

To evaluate the effect of intravitreal bevacizumab (Avastin; Genentech, Inc., South San Francisco, CA) injections on visual acuity and foveal retinal thickness in patients with central retinal vein occlusion (CRVO). In this prospective, noncomparative, consecutive, interventional case series, 46 patients received repeated intravitreal injections (1.25 mg) of bevacizumab. Main outcome measures were visual acuity (Snellen and ETDRS charts) and optical coherence tomography measurements in a 6-month follow-up period. Mean visual acuity improved from 20/250 at baseline to 20/80 at the 6-month follow-up (P < 0.001). ETDRS chart findings revealed a mean letter gain +/-SD from baseline to 6 months of 13.9 +/- 14.4 letters. Mean central retinal thickness +/-SD decreased from 535 +/- 148 microm at baseline to 323 +/- 116 microm at the 6-month follow-up. Ischemic CRVO was associated with significantly lower visual acuity than nonischemic CRVO (P < 0.001). However, visual acuity gain was similar in both groups. Independent of duration of symptoms, CRVO was associated with a similar gain in visual acuity. Intravitreal injection of bevacizumab appears to be a new treatment option for patients with macular edema secondary to CRVO.

Preservative-free triamcinolone acetonide suspension developed for intravitreal injection.

PubMed

Bitter, Christoph; Suter, Katja; Figueiredo, Verena; Pruente, Christian; Hatz, Katja; Surber, Christian

2008-02-01

All commercially available triamcinolone acetonide (TACA) suspensions, used for intravitreal treatment, contain retinal toxic vehicles (e.g., benzyl alcohol, solubilizer). Our aim was to find a convenient and reproducible method to compound a completely preservative-free TACA suspension, adapted to the intraocular physiology, with consistent quality (i.e., proven sterility and stability, constant content and dose uniformity, defined particle size, and 1 year shelf life). We evaluated two published (Membrane-filter, Centrifugation) and a newly developed method (Direct Suspending) to compound TACA suspensions for intravitreal injection. Parameters as TACA content (HPLC), particle size (microscopy and laser spectrometry), sterility, and bacterial endotoxins were assessed. Stability testing (at room temperature and 40 degrees C) was performed: color and homogeneity (visually), particle size (microscopically), TACA content and dose uniformity (HPLC) were analyzed according to International Conference on Harmonisation guidelines. Contrary to the known methods, the direct suspending method is convenient, provides a TACA suspension, which fulfills all compendial requirements, and has a 2-year shelf life. We developed a simple, reproducible method to compound stable, completely preservative-free TACA suspensions with a reasonable shelf-life, which enables to study the effect of intravitreal TACA--not biased by varying doses and toxic compounds or their residues.

Intravitreal injection of ziv-aflibercept in the treatment of choroidal and retinal vascular diseases.

PubMed

HodjatJalali, Kamran; Mehravaran, Shiva; Faghihi, Hooshang; Hashemi, Hassan; Kazemi, Pegah; Rastad, Hadith

2017-09-01

To investigate the short-term outcomes after intravitreal injection of ziv-aflibercept in the treatment of choroidal and retinal vascular diseases. Thirty-four eyes of 29 patients with age-related macular degeneration (AMD), diabetic retinopathy, and retinal vein occlusion (RVO) received a single dose intravitreal injection of 0.05 ml ziv-aflibercept (1.25 mg). Visual acuity, spectral domain optical coherence tomography (SD-OCT) activity, and possible side effects were assessed before and at 1 week and 1 month after the intervention. At 1 month after treatment, mean central macular thickness (CMT) significantly decreased from 531.09 μm to 339.5 μm ( P  < 0.001), and no signs of side effects were observed in any subject. All patients responded to treatment in terms of reduction in CMT. The improvement in visual acuity was statistically non-significant. Our findings suggest that a single dose intravitreal injection of ziv-aflibercept may have acceptable relative safety and efficacy in the treatment of patients with intraocular vascular disease. The trial was registered in the Iranian Registry of Clinical Trials (IRCT2015081723651N1).

Quantitative evaluation of reduction of plaque-like hard exudates in diabetic macular edema after intravitreal triamcinolone injection.

PubMed

Cekiç, Osman; Bardak, Yavuz; Tiğ, U Sahin; Yildizoğlu, Uzeyir; Bardak, Handan

2008-04-01

To describe a new method of quantifying the amount of plaque-like hard exudates after intravitreal triamcinolone acetonide injection in diabetic macular edema. This study included 22 eyes of 14 patients (mean age, 63 years) with chronic diabetic macular edema and plaque-like hard exudates. The patients were injected with a single dose of 4 mg intravitreal triamcinolone acetonide. The optic disc size as relative size unit was taken to quantify the hard exudates: Total areas of exudates and the optic nerve head were computed from fundus pictures with a digital analysis program on magnified images. The former was divided by the latter, and the results were expressed as a percentage value. The ratio was used to track improvements in a given eye over 6 months. Average ratio of hard exudates to optic nerve head area reduced to 81% of its initial value at 1 month (P=0.007), to 54% at 3 months (P<0.001) and to 41% at 6 months (P<0.001). The new method allowed detection of a significant reduction of ratio of hard exudates to optic disc area of diabetic plaque-like hard exudates following 4 mg intravitreal triamcinolone.

Stem Cell Banking for Regenerative and Personalized Medicine

PubMed Central

Harris, David T.

2014-01-01

Regenerative medicine, tissue engineering and gene therapy offer the opportunity to treat and cure many of today’s intractable afflictions. These approaches to personalized medicine often utilize stem cells to accomplish these goals. However, stem cells can be negatively affected by donor variables such as age and health status at the time of collection, compromising their efficacy. Stem cell banking offers the opportunity to cryogenically preserve stem cells at their most potent state for later use in these applications. Practical stem cell sources include bone marrow, umbilical cord blood and tissue, and adipose tissue. Each of these sources contains stem cells that can be obtained from most individuals, without too much difficulty and in an economical fashion. This review will discuss the advantages and disadvantages of each stem cell source, factors to be considered when contemplating banking each stem cell source, the methodology required to bank each stem cell source, and finally, current and future clinical uses of each stem cell source. PMID:28548060

Nine Things to Know About Stem Cell Treatments

MedlinePlus

... Toggle Nav Nine Things To Know About Stem Cell Treatments Home > Stem Cells and Medicine > Nine Things ... About Stem Cell Treatments Many clinics offering stem cell treatments make claims that are not supported by ...

Cancer (stem) cell differentiation: An inherent or acquired property?

PubMed

Mohr, Marieke; Zänker, Kurt S; Dittmar, Thomas

2015-12-01

There is a growing list of data indicating that cancer (stem) cells could functionally adapt foreign tissue features, such as endothelial-like cells or neuroendocrine cells, express lineage markers or could differentiate into various lineages in response to appropriate differentiation criteria. The finding that cancer (stem) cells may possess some kind of differentiation capacity poses the question whether this might be an inherent or acquired property. Cancer stem cells share stem cell characteristics and may thus possess an inherent differentiation capacity enabling the cells to respond to various differentiation stimuli. Considering the plasticity of cancer (stem) cells, even non-tumorigenic (and putatively non-differentiable) tumor cells could give rise to tumorigenic tumor stem cells, exhibiting stem cell characteristics including an inherent differentiation capacity. On the contrary, cancer (stem) cells may have acquired differentiation capacity as a consequence of a previous cell fusion event with cell types exhibiting differentiation potential and being fusogenic, such as macrophages or stem cells. Of pivotal interest in a tumor context are macrophages, which chiefly foster the chronically inflamed tumor microenvironment. Because chronically inflamed tissue is a well-known trigger for cell fusion and both macrophages and stem cells are highly fusogenic we conclude that cell fusion events between these cell types and cancer (stem) cells should frequently occur, thereby giving rise to hybrid cells exhibiting not only novel properties, like an enhanced metastatogenic phenotype, but also parental characteristics, such as differentiation capacity. Conceivably, the combination of both properties might be advantageous for metastasizing cancer (stem) cells to adapt better and faster to a foreign organ tissue environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sox10+ adult stem cells contribute to biomaterial encapsulation and microvascularization

PubMed Central

Wang, Dong; Wang, Aijun; Wu, Fan; Qiu, Xuefeng; Li, Ye; Chu, Julia; Huang, Wen-Chin; Xu, Kang; Gong, Xiaohua; Li, Song

2017-01-01

Implanted biomaterials and biomedical devices generally induce foreign body reaction and end up with encapsulation by a dense avascular fibrous layer enriched in extracellular matrix. Fibroblasts/myofibroblasts are thought to be the major cell type involved in encapsulation, but it is unclear whether and how stem cells contribute to this process. Here we show, for the first time, that Sox10+ adult stem cells contribute to both encapsulation and microvessel formation. Sox10+ adult stem cells were found sparsely in the stroma of subcutaneous loose connective tissues. Upon subcutaneous biomaterial implantation, Sox10+ stem cells were activated and recruited to the biomaterial scaffold, and differentiated into fibroblasts and then myofibroblasts. This differentiation process from Sox10+ stem cells to myofibroblasts could be recapitulated in vitro. On the other hand, Sox10+ stem cells could differentiate into perivascular cells to stabilize newly formed microvessels. Sox10+ stem cells and endothelial cells in three-dimensional co-culture self-assembled into microvessels, and platelet-derived growth factor had chemotactic effect on Sox10+ stem cells. Transplanted Sox10+ stem cells differentiated into smooth muscle cells to stabilize functional microvessels. These findings demonstrate the critical role of adult stem cells in tissue remodeling and unravel the complexity of stem cell fate determination. PMID:28071739

Tumor suppressors Sav/Scrib and oncogene Ras regulate stem cell transformation in adult Drosophila Malpighian Tubules

PubMed Central

Zeng, Xiankun; Singh, Shree Ram; Hou, David; Hou, Steven X.

2012-01-01

An increasing body of evidence suggests that tumors might originate from a few transformed cells that share many properties with normal stem cells. However, it remains unclear how normal stem cells are transformed into cancer stem cells. Here, we demonstrated that mutations causing the loss of tumor suppressor Sav or Scrib or activation of the oncogene Ras transform normal stem cells into cancer stem cells through a multistep process in the adult Drosophila Malpighian Tubules (MTs). In wild-type MTs, each stem cell generates one self-renewing and one differentiating daughter cell. However, in flies with loss-of-function sav or scrib or gain-of-function Ras mutations, both daughter cells grew and behaved like stem cells, leading to the formation of tumors in MTs. Ras functioned downstream of Sav and Scrib in regulating the stem cell transformation. The Ras-transformed stem cells exhibited many of the hallmarks of cancer, such as increased proliferation, reduced cell death, and failure to differentiate. We further demonstrated that several signal transduction pathways (including MEK/MAPK, RhoA, PKA, and TOR) mediate Rasṕ function in the stem cell transformation. Therefore, we have identified a molecular mechanism that regulates stem cell transformation, and this finding may lead to strategies for preventing tumor formation in certain organs. PMID:20432470

The king is dead, long live the king: entering a new era of stem cell research and clinical development.

PubMed

Ichim, Thomas; Riordan, Neil H; Stroncek, David F

2011-12-20

In mid November the biopharma industry was shocked by the announcement from Geron that they were ending work on embryonic stem cell research and therapy. For more than 10 years the public image of all stem cell research has been equated with embryonic stem cells. Unfortunately, a fundamentally important medical and financial fact was being ignored: embryonic stem cell therapy is extremely immature. In parallel to efforts in embryonic stem cell research and development, scientists and physicians in the field of adult stem cells realized that the natural role of adult stem cells in the body is to promote healing and to act like endogenous "repair cells" and, as a result, numerous companies have entered the field of adult stem cell therapy with the goal of expanding numbers of adult stem cells for administration to patients with various conditions. In contrast to embryonic stem cells, which are extremely expensive and potentially dangerous, adult cell cells are inexpensive and have an excellent safety record when used in humans. Many studies are now showing that adult stem cells are practical, patient-applicable, therapeutics that are very close to being available for incorporation into the practice of medicine. These events signal the entrance of the field of stem cells into a new era: an era where hype and misinformation no longer triumph over economic and medical realities.

Control of stem cell fate by engineering their micro and nanoenvironment

PubMed Central

Griffin, Michelle F; Butler, Peter E; Seifalian, Alexander M; Kalaskar, Deepak M

2015-01-01

Stem cells are capable of long-term self-renewal and differentiation into specialised cell types, making them an ideal candidate for a cell source for regenerative medicine. The control of stem cell fate has become a major area of interest in the field of regenerative medicine and therapeutic intervention. Conventional methods of chemically inducing stem cells into specific lineages is being challenged by the advances in biomaterial technology, with evidence highlighting that material properties are capable of driving stem cell fate. Materials are being designed to mimic the clues stem cells receive in their in vivo stem cell niche including topographical and chemical instructions. Nanotopographical clues that mimic the extracellular matrix (ECM) in vivo have shown to regulate stem cell differentiation. The delivery of ECM components on biomaterials in the form of short peptides sequences has also proved successful in directing stem cell lineage. Growth factors responsible for controlling stem cell fate in vivo have also been delivered via biomaterials to provide clues to determine stem cell differentiation. An alternative approach to guide stem cells fate is to provide genetic clues including delivering DNA plasmids and small interfering RNAs via scaffolds. This review, aims to provide an overview of the topographical, chemical and molecular clues that biomaterials can provide to guide stem cell fate. The promising features and challenges of such approaches will be highlighted, to provide directions for future advancements in this exciting area of stem cell translation for regenerative medicine. PMID:25621104

The Neurovascular Properties of Dental Stem Cells and Their Importance in Dental Tissue Engineering

PubMed Central

Ratajczak, Jessica; Bronckaers, Annelies; Dillen, Yörg; Gervois, Pascal; Vangansewinkel, Tim; Driesen, Ronald B.; Wolfs, Esther; Lambrichts, Ivo

2016-01-01

Within the field of tissue engineering, natural tissues are reconstructed by combining growth factors, stem cells, and different biomaterials to serve as a scaffold for novel tissue growth. As adequate vascularization and innervation are essential components for the viability of regenerated tissues, there is a high need for easily accessible stem cells that are capable of supporting these functions. Within the human tooth and its surrounding tissues, different stem cell populations can be distinguished, such as dental pulp stem cells, stem cells from human deciduous teeth, stem cells from the apical papilla, dental follicle stem cells, and periodontal ligament stem cells. Given their straightforward and relatively easy isolation from extracted third molars, dental stem cells (DSCs) have become an attractive source of mesenchymal-like stem cells. Over the past decade, there have been numerous studies supporting the angiogenic, neuroprotective, and neurotrophic effects of the DSC secretome. Together with their ability to differentiate into endothelial cells and neural cell types, this makes DSCs suitable candidates for dental tissue engineering and nerve injury repair. PMID:27688777

Multipotent Stem Cell and Reproduction.

PubMed

Khanlarkhani, Neda; Baazm, Maryam; Mohammadzadeh, Farzaneh; Najafi, Atefeh; Mehdinejadiani, Shayesteh; Sobhani, Aligholi

Stem cells are self-renewing and undifferentiated cell types that can be differentiate into functional cells. Stem cells can be classified into two main types based on their source of origin: Embryonic and Adult stem cells. Stem cells also classified based on the range of differentiation potentials into Totipotent, Pluripotent, Multipotent, and Unipotent. Multipotent stem cells have the ability to differentiate into all cell types within one particular lineage. There are plentiful advantages and usages for multipotent stem cells. Multipotent Stem cells act as a significant key in procedure of development, tissue repair, and protection. The accessibility and adaptability of these amazing cells create them a great therapeutic choice for different part of medical approaches, and it becomes interesting topic in the scientific researches to found obvious method for the most advantageous use of MSC-based therapies. Recent studies in the field of stem cell biology have provided new perspectives and opportunities for the treatment of infertility disorders.

Strategies to improve homing of mesenchymal stem cells for greater efficacy in stem cell therapy.

PubMed

Naderi-Meshkin, Hojjat; Bahrami, Ahmad Reza; Bidkhori, Hamid Reza; Mirahmadi, Mahdi; Ahmadiankia, Naghmeh

2015-01-01

Stem/progenitor cell-based therapeutic approach in clinical practice has been an elusive dream in medical sciences, and improvement of stem cell homing is one of major challenges in cell therapy programs. Stem/progenitor cells have a homing response to injured tissues/organs, mediated by interactions of chemokine receptors expressed on the cells and chemokines secreted by the injured tissue. For improvement of directed homing of the cells, many techniques have been developed either to engineer stem/progenitor cells with higher amount of chemokine receptors (stem cell-based strategies) or to modulate the target tissues to release higher level of the corresponding chemokines (target tissue-based strategies). This review discusses both of these strategies involved in the improvement of stem cell homing focusing on mesenchymal stem cells as most frequent studied model in cellular therapies. © 2014 International Federation for Cell Biology.

College Students' Conceptions of Stem Cells, Stem Cell Research, and Cloning

ERIC Educational Resources Information Center

Concannon, James P.; Siegel, Marcelle A.; Halverson, Kristy; Freyermuth, Sharyn

2010-01-01

In this study, we examined 96 undergraduate non-science majors' conceptions of stem cells, stem cell research, and cloning. This study was performed at a large, Midwest, research extensive university. Participants in the study were asked to answer 23 questions relating to stem cells, stem cell research, and cloning in an on-line assessment before…

Stem cell biobanks.

PubMed

Bardelli, Silvana

2010-04-01

Stem cells contribute to innate healing and harbor a promising role for regenerative medicine. Stem cell banking through long-term storage of different stem cell platforms represents a fundamental source to preserve original features of stem cells for patient-specific clinical applications. Stem cell research and clinical translation constitute fundamental and indivisible modules catalyzed through biobanking activity, generating a return of investment.

Muscle Stem Cells: A Model System for Adult Stem Cell Biology.

PubMed

Cornelison, Ddw; Perdiguero, Eusebio

2017-01-01

Skeletal muscle stem cells, originally termed satellite cells for their position adjacent to differentiated muscle fibers, are absolutely required for the process of skeletal muscle repair and regeneration. In the last decade, satellite cells have become one of the most studied adult stem cell systems and have emerged as a standard model not only in the field of stem cell-driven tissue regeneration but also in stem cell dysfunction and aging. Here, we provide background in the field and discuss recent advances in our understanding of muscle stem cell function and dysfunction, particularly in the case of aging, and the potential involvement of muscle stem cells in genetic diseases such as the muscular dystrophies.

Redox regulation of plant stem cell fate.

PubMed

Zeng, Jian; Dong, Zhicheng; Wu, Haijun; Tian, Zhaoxia; Zhao, Zhong

2017-10-02

Despite the importance of stem cells in plant and animal development, the common mechanisms of stem cell maintenance in both systems have remained elusive. Recently, the importance of hydrogen peroxide (H 2 O 2 ) signaling in priming stem cell differentiation has been extensively studied in animals. Here, we show that different forms of reactive oxygen species (ROS) have antagonistic roles in plant stem cell regulation, which were established by distinct spatiotemporal patterns of ROS-metabolizing enzymes. The superoxide anion (O2·-) is markedly enriched in stem cells to activate WUSCHEL and maintain stemness, whereas H 2 O 2 is more abundant in the differentiating peripheral zone to promote stem cell differentiation. Moreover, H 2 O 2 negatively regulates O2·- biosynthesis in stem cells, and increasing H 2 O 2 levels or scavenging O2·- leads to the termination of stem cells. Our results provide a mechanistic framework for ROS-mediated control of plant stem cell fate and demonstrate that the balance between O2·- and H 2 O 2 is key to stem cell maintenance and differentiation. © 2017 The Authors.

Ocular Stem Cell Research from Basic Science to Clinical Application: A Report from Zhongshan Ophthalmic Center Ocular Stem Cell Symposium

PubMed Central

Ouyang, Hong; Goldberg, Jeffrey L.; Chen, Shuyi; Li, Wei; Xu, Guo-Tong; Li, Wei; Zhang, Kang; Nussenblatt, Robert B.; Liu, Yizhi; Xie, Ting; Chan, Chi-Chao; Zack, Donald J.

2016-01-01

Stem cells hold promise for treating a wide variety of diseases, including degenerative disorders of the eye. The eye is an ideal organ for stem cell therapy because of its relative immunological privilege, surgical accessibility, and its being a self-contained system. The eye also has many potential target diseases amenable to stem cell-based treatment, such as corneal limbal stem cell deficiency, glaucoma, age-related macular degeneration (AMD), and retinitis pigmentosa (RP). Among them, AMD and glaucoma are the two most common diseases, affecting over 200 million people worldwide. Recent results on the clinical trial of retinal pigment epithelial (RPE) cells from human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) in treating dry AMD and Stargardt’s disease in the US, Japan, England, and China have generated great excitement and hope. This marks the beginning of the ocular stem cell therapy era. The recent Zhongshan Ophthalmic Center Ocular Stem Cell Symposium discussed the potential applications of various stem cell types in stem cell-based therapies, drug discoveries and tissue engineering for treating ocular diseases. PMID:27102165

StemTextSearch: Stem cell gene database with evidence from abstracts.

PubMed

Chen, Chou-Cheng; Ho, Chung-Liang

2017-05-01

Previous studies have used many methods to find biomarkers in stem cells, including text mining, experimental data and image storage. However, no text-mining methods have yet been developed which can identify whether a gene plays a positive or negative role in stem cells. StemTextSearch identifies the role of a gene in stem cells by using a text-mining method to find combinations of gene regulation, stem-cell regulation and cell processes in the same sentences of biomedical abstracts. The dataset includes 5797 genes, with 1534 genes having positive roles in stem cells, 1335 genes having negative roles, 1654 genes with both positive and negative roles, and 1274 with an uncertain role. The precision of gene role in StemTextSearch is 0.66, and the recall is 0.78. StemTextSearch is a web-based engine with queries that specify (i) gene, (ii) category of stem cell, (iii) gene role, (iv) gene regulation, (v) cell process, (vi) stem-cell regulation, and (vii) species. StemTextSearch is available through http://bio.yungyun.com.tw/StemTextSearch.aspx. Copyright © 2017. Published by Elsevier Inc.

Application of Stem Cell Technology in Dental Regenerative Medicine.

PubMed

Feng, Ruoxue; Lengner, Chistopher

2013-07-01

In this review, we summarize the current literature regarding the isolation and characterization of dental tissue-derived stem cells and address the potential of these cell types for use in regenerative cell transplantation therapy. Looking forward, platforms for the delivery of stem cells via scaffolds and the use of growth factors and cytokines for enhancing dental stem cell self-renewal and differentiation are discussed. We aim to understand the developmental origins of dental tissues in an effort to elucidate the molecular pathways governing the genesis of somatic dental stem cells. The advantages and disadvantages of several dental stem cells are discussed, including the developmental stage and specific locations from which these cells can be purified. In particular, stem cells from human exfoliated deciduous teeth may act as a very practical and easily accessibly reservoir for autologous stem cells and hold the most value in stem cell therapy. Dental pulp stem cells and periodontal ligament stem cells should also be considered for their triple lineage differentiation ability and relative ease of isolation. Further, we address the potentials and limitations of induced pluripotent stem cells as a cell source in dental regenerative. From an economical and a practical standpoint, dental stem cell therapy would be most easily applied in the prevention of periodontal ligament detachment and bone atrophy, as well as in the regeneration of dentin-pulp complex. In contrast, cell-based tooth replacement due to decay or other oral pathology seems, at the current time, an untenable approach.

The UK Stem Cell Bank: a UK government-funded, international resource center for stem cell research.

PubMed

Stacey, Glyn; Hunt, Charles J

2006-01-01

The UK Stem Cell Bank is a UK Research Council-funded initiative that aims to provide ethically sourced and quality controlled stocks of cells for researchers and also establish seed stocks of cell lines for clinical trials. Whilst the Bank is prohibited from carrying out basic stem cell research (to avoid conflicts of interest) it is working to improve stem cell banking procedures including cryopreservation, characterization and quality control. The Bank also supports training activities and has provided the hub for the International Stem Cell Initiative, which includes 17 expert stem cell centers aiming to characterize a large number of human embryonic stem cell lines in a standardized way to improve our understanding of the characteristics of these cells.

Methods for Stem Cell Production and Therapy

NASA Technical Reports Server (NTRS)

Valluri, Jagan V. (Inventor); Claudio, Pier Paolo (Inventor)

2015-01-01

The present invention relates to methods for rapidly expanding a stem cell population with or without culture supplements in simulated microgravity conditions. The present invention relates to methods for rapidly increasing the life span of stem cell populations without culture supplements in simulated microgravity conditions. The present invention also relates to methods for increasing the sensitivity of cancer stem cells to chemotherapeutic agents by culturing the cancer stem cells under microgravity conditions and in the presence of omega-3 fatty acids. The methods of the present invention can also be used to proliferate cancer cells by culturing them in the presence of omega-3 fatty acids. The present invention also relates to methods for testing the sensitivity of cancer cells and cancer stem cells to chemotherapeutic agents by culturing the cancer cells and cancer stem cells under microgravity conditions. The methods of the present invention can also be used to produce tissue for use in transplantation by culturing stem cells or cancer stem cells under microgravity conditions. The methods of the present invention can also be used to produce cellular factors and growth factors by culturing stem cells or cancer stem cells under microgravity conditions. The methods of the present invention can also be used to produce cellular factors and growth factors to promote differentiation of cancer stem cells under microgravity conditions.

Dental pulp stem cells in regenerative dentistry.

PubMed

Casagrande, Luciano; Cordeiro, Mabel M; Nör, Silvia A; Nör, Jacques E

2011-01-01

Stem cells constitute the source of differentiated cells for the generation of tissues during development, and for regeneration of tissues that are diseased or injured postnatally. In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that span from Alzheimer's disease to cardiac ischemia to bone or tooth loss. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental pulp is considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that dental pulp stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. The dental pulp stem cells are highly proliferative. This characteristic facilitates ex vivo expansion and enhances the translational potential of these cells. Notably, the dental pulp is arguably the most accessible source of postnatal stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental pulp an attractive source of mesenchymal stem cells for tissue regeneration. This review discusses fundamental concepts of stem cell biology and tissue engineering within the context of regenerative dentistry.

Translating stem cell therapies: the role of companion animals in regenerative medicine

PubMed Central

Volk, Susan W.; Theoret, Christine

2013-01-01

Veterinarians and veterinary medicine have been integral to the development of stem cell therapies. The contributions of large animal experimental models to the development and refinement of modern hematopoietic stem cell transplantation were noted nearly five decades ago. More recent advances in adult stem cell/regenerative cell therapies continue to expand knowledge of the basic biology and clinical applications of stem cells. A relatively liberal legal and ethical regulation of stem cell research in veterinary medicine has facilitated the development and in some instances clinical translation of a variety of cell-based therapies involving hematopoietic (HSC) and mesenchymal stem cells (MSC) as well as other adult regenerative cells and recently embryonic stem cells (ESC) and induced pluripotent stem cells (iPSC). In fact, many of the pioneering developments in these fields of stem cell research have been achieved through collaborations of veterinary and human scientists. This review aims to provide an overview of the contribution of large animal veterinary models in advancing stem cell therapies for both human and clinical veterinary applications. Moreover, in the context of the “One Health Initiative”, the role veterinary patients may play in the future evolution of stem cell therapies for both human and animal patients will be explored. PMID:23627495

Wnt6 maintains anterior escort cells as an integral component of the germline stem cell niche

PubMed Central

2018-01-01

ABSTRACT Stem cells reside in a niche, a local environment whose cellular and molecular complexity is still being elucidated. In Drosophila ovaries, germline stem cells depend on cap cells for self-renewing signals and physical attachment. Germline stem cells also contact the anterior escort cells, and here we report that anterior escort cells are absolutely required for germline stem cell maintenance. When escort cells die from impaired Wnt signaling or hid expression, the loss of anterior escort cells causes loss of germline stem cells. Anterior escort cells function as an integral niche component by promoting DE-cadherin anchorage and by transiently expressing the Dpp ligand to promote full-strength BMP signaling in germline stem cells. Anterior escort cells are maintained by Wnt6 ligands produced by cap cells; without Wnt6 signaling, anterior escort cells die leaving vacancies in the niche, leading to loss of germline stem cells. Our data identify anterior escort cells as constituents of the germline stem cell niche, maintained by a cap cell-produced Wnt6 survival signal. PMID:29361569

Wnt6 maintains anterior escort cells as an integral component of the germline stem cell niche.

PubMed

Wang, Xiaoxi; Page-McCaw, Andrea

2018-02-07

Stem cells reside in a niche, a local environment whose cellular and molecular complexity is still being elucidated. In Drosophila ovaries, germline stem cells depend on cap cells for self-renewing signals and physical attachment. Germline stem cells also contact the anterior escort cells, and here we report that anterior escort cells are absolutely required for germline stem cell maintenance. When escort cells die from impaired Wnt signaling or hid expression, the loss of anterior escort cells causes loss of germline stem cells. Anterior escort cells function as an integral niche component by promoting DE-cadherin anchorage and by transiently expressing the Dpp ligand to promote full-strength BMP signaling in germline stem cells. Anterior escort cells are maintained by Wnt6 ligands produced by cap cells; without Wnt6 signaling, anterior escort cells die leaving vacancies in the niche, leading to loss of germline stem cells. Our data identify anterior escort cells as constituents of the germline stem cell niche, maintained by a cap cell-produced Wnt6 survival signal. © 2018. Published by The Company of Biologists Ltd.

21st Nantes Actualités Transplantation: "When Stem Cells Meet Immunology".

PubMed

Anegon, Ignacio; Nguyen, Tuan Huy

2017-01-01

"When Stem Cells Meet Immunology" has been the topic of the 21st annual "Nantes Actualités en Transplantation" meeting (June 9-10, 2016, Nantes, France). This meeting brought together pioneers and leading experts in the fields of stem cells, biomaterials and immunoregulation. Presentations covered multipotent (mesenchymal and hematopoietic) and pluripotent stem cells (embryonic and induced) for regenerative medicine of incurable diseases, immunotherapy and blood transfusions. An additional focus had been immune rejections and responses of allogeneic or autologous stem cells. Conversely, stem cells are also able to directly modulate the immune response through the production of immunoregulatory molecules. Moreover, stem cells may also provide an unlimited source of immune cells (DCs, NK cells, B cells, and T cells) that can operate as "super" immune cells, for example, through genetic engineering with chimeric antigen receptors.This meeting report puts presentations into an overall context highlighting new potential biomarkers for potency prediction of mesenchymal stem cell-derived and pluripotent stem cell-derived multicellular organoids. Finally, we propose future directions arising from the flourishing encounter of stem cell and immune biology.

Differential sensitivity of Glioma stem cells to Aurora kinase A inhibitors: implications for stem cell mitosis and centrosome dynamics.

PubMed

Mannino, Mariella; Gomez-Roman, Natividad; Hochegger, Helfrid; Chalmers, Anthony J

2014-07-01

Glioma stem-cell-like cells are considered to be responsible for treatment resistance and tumour recurrence following chemo-radiation in glioblastoma patients, but specific targets by which to kill the cancer stem cell population remain elusive. A characteristic feature of stem cells is their ability to undergo both symmetric and asymmetric cell divisions. In this study we have analysed specific features of glioma stem cell mitosis. We found that glioma stem cells appear to be highly prone to undergo aberrant cell division and polyploidization. Moreover, we discovered a pronounced change in the dynamic of mitotic centrosome maturation in these cells. Accordingly, glioma stem cell survival appeared to be strongly dependent on Aurora A activity. Unlike differentiated cells, glioma stem cells responded to moderate Aurora A inhibition with spindle defects, polyploidization and a dramatic increase in cellular senescence, and were selectively sensitive to Aurora A and Plk1 inhibitor treatment. Our study proposes inhibition of centrosomal kinases as a novel strategy to selectively target glioma stem cells. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Effect of aging on stem cells

PubMed Central

Ahmed, Abu Shufian Ishtiaq; Sheng, Matilda HC; Wasnik, Samiksha; Baylink, David J; Lau, Kin-Hing William

2017-01-01

Pluripotent stem cells have the remarkable self-renewal ability and are capable of differentiating into multiple diverse cells. There is increasing evidence that the aging process can have adverse effects on stem cells. As stem cells age, their renewal ability deteriorates and their ability to differentiate into the various cell types is altered. Accordingly, it is suggested aging-induced deterioration of stem cell functions may play a key role in the pathophysiology of the various aging-associated disorders. Understanding the role of the aging process in deterioration of stem cell function is crucial, not only in understanding the pathophysiology of aging-associated disorders, but also in future development of novel effective stem cell-based therapies to treat aging-associated diseases. This review article first focuses on the basis of the various aging disease-related stem cell dysfunction. It then addresses the several concepts on the potential mechanism that causes aging-related stem cell dysfunction. It also briefly discusses the current potential therapies under development for aging-associated stem cell defects. PMID:28261550

Engineering Stem Cells for Biomedical Applications

PubMed Central

Yin, Perry T.; Han, Edward

2018-01-01

Stem cells are characterized by a number of useful properties, including their ability to migrate, differentiate, and secrete a variety of therapeutic molecules such as immunomodulatory factors. As such, numerous pre-clinical and clinical studies have utilized stem cell-based therapies and demonstrated their tremendous potential for the treatment of various human diseases and disorders. Recently, efforts have focused on engineering stem cells in order to further enhance their innate abilities as well as to confer them with new functionalities, which can then be used in various biomedical applications. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle loading and delivery, and even small molecule drug delivery. The present Review gives an in-depth account of the current status of engineered stem cells, including potential cell sources, the most common methods used to engineer stem cells, and the utilization of engineered stem cells in various biomedical applications, with a particular focus on tissue regeneration, the treatment of immunodeficiency diseases, and cancer. PMID:25772134

Therapeutic potential of dental stem cells

PubMed Central

Chalisserry, Elna Paul; Nam, Seung Yun; Park, Sang Hyug; Anil, Sukumaran

2017-01-01

Stem cell biology has become an important field in regenerative medicine and tissue engineering therapy since the discovery and characterization of mesenchymal stem cells. Stem cell populations have also been isolated from human dental tissues, including dental pulp stem cells, stem cells from human exfoliated deciduous teeth, stem cells from apical papilla, dental follicle progenitor cells, and periodontal ligament stem cells. Dental stem cells are relatively easily obtainable and exhibit high plasticity and multipotential capabilities. The dental stem cells represent a gold standard for neural-crest-derived bone reconstruction in humans and can be used for the repair of body defects in low-risk autologous therapeutic strategies. The bioengineering technologies developed for tooth regeneration will make substantial contributions to understand the developmental process and will encourage future organ replacement by regenerative therapies in a wide variety of organs such as the liver, kidney, and heart. The concept of developing tooth banking and preservation of dental stem cells is promising. Further research in the area has the potential to herald a new dawn in effective treatment of notoriously difficult diseases which could prove highly beneficial to mankind in the long run. PMID:28616151

Single-cell sequencing in stem cell biology.

PubMed

Wen, Lu; Tang, Fuchou

2016-04-15

Cell-to-cell variation and heterogeneity are fundamental and intrinsic characteristics of stem cell populations, but these differences are masked when bulk cells are used for omic analysis. Single-cell sequencing technologies serve as powerful tools to dissect cellular heterogeneity comprehensively and to identify distinct phenotypic cell types, even within a 'homogeneous' stem cell population. These technologies, including single-cell genome, epigenome, and transcriptome sequencing technologies, have been developing rapidly in recent years. The application of these methods to different types of stem cells, including pluripotent stem cells and tissue-specific stem cells, has led to exciting new findings in the stem cell field. In this review, we discuss the recent progress as well as future perspectives in the methodologies and applications of single-cell omic sequencing technologies.

The Implications of the Cancer Stem Cell Hypothesis for Neuro-Oncology and Neurology.

PubMed

Rich, Jeremy N

2008-05-01

The cancer stem cell hypothesis posits that cancers contain a subset of neoplastic cells that propagate and maintain tumors through sustained self-renewal and potent tumorigenecity. Recent excitement has been generated by a number of reports that have demonstrated the existence of cancer stem cells in several types of brain tumors. Brain cancer stem cells - also called tumor initiating cells or tumor propagating cells - share features with normal neural stem cells but do not necessarily originate from stem cells. Although most cancers have only a small fraction of cancer stem cells, these tumor cells have been shown in laboratory studies to contribute to therapeutic resistance, formation of new blood vessels to supply the tumor, and tumor spread. As malignant brain tumors rank among the deadliest of all neurologic diseases, the identification of new cellular targets may have profound implications in neuro-oncology. Novel drugs that target stem cell pathways active in brain tumors have been efficacious against cancer stem cells suggesting that anti-cancer stem cell therapies may advance brain tumor therapy. The cancer stem cell hypothesis may have several implications for other neurologic diseases as caution must be exercised in activating stem cell maintenance pathways in cellular therapies for neurodegenerative diseases. The ability for a small fraction of cells to determine the overall course of a disease may also inform new paradigms of disease that may translate into improved patient outcomes.

Can bone marrow differentiate into renal cells?

PubMed

Imai, Enyu; Ito, Takahito

2002-10-01

A considerable plasticity of adult stem cells has been confirmed in a wide variety of tissues. In particular, the pluripotency of bone marrow-derived stem cells may influence the regeneration of injured tissues and may provide novel avenues in regenerative medicine. Bone marrow contains at least hematopoietic and mesenchymal stem cells, and both can differentiate into a wide range of differentiated cells. Side population (SP) cells, which are originally defined in bone marrow cells by high efflux of DNA-binding dye, seem to be a new class of multipotent stem cells. Irrespective of the approach used to obtain stem cells, the fates of marrow-derived cells following bone marrow transplantation can be traced by labeling donor cells with green fluorescence protein or by identifying donor Y chromosome in female recipients. So far, bone marrow-derived cells have been reported to differentiate into renal cells, including mesangial cells, endothelial cells, podocytes, and tubular cells in the kidney, although controversy exists. Further studies are required to address this issue. Cell therapy will be promising when we learn to control stem cells such as bone marrow-derived stem cells, embryonic stem cells, and resident stem cells in the kidney. Identification of factors that support stem cells or promote their differentiation should provide a relevant step towards cell therapy.

[The emerging technology of tissue engineering : Focus on stem cell niche].

PubMed

Schlötzer-Schrehardt, U; Freudenberg, U; Kruse, F E

2017-04-01

Limbal stem cells reside in a highly specialized complex microenvironment that is known as the stem cell niche, an anatomically protected region at the bottom of the Palisades of Vogt, where the stem cells are located and where their quiescence, proliferation and differentiation are maintained in balance. Besides the epithelial stem and progenitor cell clusters, the limbal niche comprises several types of supporting niche cells and a specific extracellular matrix mediating biochemical and biophysical signals. Stem cell-based tissue engineering aims to mimic the native stem cell niche and to present appropriate microenvironmental cues in a controlled and reproducible fashion in order to maintain stem cell function within the graft. Current therapeutic approaches for ex vivo expansion of limbal stem cells only take advantage of surrogate niches. However, new insights into the molecular composition of the limbal niche and innovative biosynthetic scaffolds have stimulated novel strategies for niche-driven stem cell cultivation. Promising experimental approaches include collagen-based organotypic coculture systems of limbal epithelial stem cells with their niche cells and biomimetic hydrogel platforms prefunctionalized with appropriate biomolecular and biophysical signals. Future translation of these novel regenerative strategies into clinical application is expected to improve long-term outcomes of limbal stem cell transplantation for ocular surface reconstruction.

Combination cell therapy with mesenchymal stem cells and neural stem cells for brain stroke in rats.

PubMed

Hosseini, Seyed Mojtaba; Farahmandnia, Mohammad; Razi, Zahra; Delavari, Somayeh; Shakibajahromi, Benafsheh; Sarvestani, Fatemeh Sabet; Kazemi, Sepehr; Semsar, Maryam

2015-05-01

Brain stroke is the second most important events that lead to disability and morbidity these days. Although, stroke is important, there is no treatment for curing this problem. Nowadays, cell therapy has opened a new window for treating central nervous system disease. In some previous studies the Mesenchymal stem cells and neural stem cells. In this study, we have designed an experiment to assess the combination cell therapy (Mesenchymal and Neural stem cells) effects on brain stroke. The Mesenchymal stem cells were isolated from adult rat bone marrow and the neural stem cells were isolated from ganglion eminence of rat embryo 14 days. The Mesenchymal stem cells were injected 1 day after middle cerebral artery occlusion (MCAO) and the neural stem cells transplanted 7 day after MCAO. After 28 days, the neurological outcomes and brain lesion volumes were evaluated. Also, the activity of Caspase 3 was assessed in different groups. The group which received combination cell therapy had better neurological examination and less brain lesion. Also the combination cell therapy group had the least Caspase 3 activity among the groups. The combination cell therapy is more effective than Mesenchymal stem cell therapy and neural stem cell therapy separately in treating the brain stroke in rats.

Application of Stem Cells in Oral Disease Therapy: Progresses and Perspectives

PubMed Central

Yang, Bo; Qiu, Yi; Zhou, Niu; Ouyang, Hong; Ding, Junjun; Cheng, Bin; Sun, Jianbo

2017-01-01

Stem cells are undifferentiated and pluripotent cells that can differentiate into specialized cells with a more specific function. Stem cell therapies become preferred methods for the treatment of multiple diseases. Oral and maxillofacial defect is one kind of the diseases that could be most possibly cured by stem cell therapies. Here we discussed oral diseases, oral adult stem cells, iPS cells, and the progresses/challenges/perspectives of application of stem cells for oral disease treatment. PMID:28421002

Cytomegalovirus retinitis diagnosed after completion of chemotherapy for acute lymphoblastic leukemia in an adolescent.

PubMed

Han, Seung Beom; Lee, Jin Hee; Lee, Jae Wook; Chung, Nack-Gyun; Cho, Bin; Kang, Jin Han; Kim, Hack-Ki; Lee, Jin Hae; Lee, Won Ki

2015-03-01

Although cytomegalovirus (CMV) retinitis is usually diagnosed in allogeneic hematopoietic cell transplantation recipients among patients with hematologic and oncologic disease, it can also occur in acute leukemia patients who have not received hematopoietic cell transplantation. However, CMV retinitis diagnosed after completion of chemotherapy for acute leukemia has not previously been reported. A 17-year-old boy was diagnosed with CMV retinitis 3 months after completion of chemotherapy for acute lymphoblastic leukemia, and his retinitis was assumed to be caused by a delayed immune reconstitution after chemotherapy. The patient was treated with intravenous and intravitreous ganciclovir therapy, and subsequently underwent surgery for retinal detachment.

Diploid, but not haploid, human embryonic stem cells can be derived from microsurgically repaired tripronuclear human zygotes

PubMed Central

Fan, Yong; Li, Rong; Huang, Jin; Yu, Yang; Qiao, Jie

2013-01-01

Human embryonic stem cells have shown tremendous potential in regenerative medicine, and the recent progress in haploid embryonic stem cells provides new insights for future applications of embryonic stem cells. Disruption of normal fertilized embryos remains controversial; thus, the development of a new source for human embryonic stem cells is important for their usefulness. Here, we investigated the feasibility of haploid and diploid embryo reconstruction and embryonic stem cell derivation using microsurgically repaired tripronuclear human zygotes. Diploid and haploid zygotes were successfully reconstructed, but a large proportion of them still had a tripolar spindle assembly. The reconstructed embryos developed to the blastocyst stage, although the loss of chromosomes was observed in these zygotes. Finally, triploid and diploid human embryonic stem cells were derived from tripronuclear and reconstructed zygotes (from which only one pronucleus was removed), but haploid human embryonic stem cells were not successfully derived from the reconstructed zygotes when two pronuclei were removed. Both triploid and diploid human embryonic stem cells showed the general characteristics of human embryonic stem cells. These results indicate that the lower embryo quality resulting from abnormal spindle assembly contributed to the failure of the haploid embryonic stem cell derivation. However, the successful derivation of diploid embryonic stem cells demonstrated that microsurgical tripronuclear zygotes are an alternative source of human embryonic stem cells. In the future, improving spindle assembly will facilitate the application of triploid zygotes to the field of haploid embryonic stem cells. PMID:23255130

Nano scaffolds and stem cell therapy in liver tissue engineering

NASA Astrophysics Data System (ADS)

Montaser, Laila M.; Fawzy, Sherin M.

2015-08-01

Tissue engineering and regenerative medicine have been constantly developing of late due to the major progress in cell and organ transplantation, as well as advances in materials science and engineering. Although stem cells hold great potential for the treatment of many injuries and degenerative diseases, several obstacles must be overcome before their therapeutic application can be realized. These include the development of advanced techniques to understand and control functions of micro environmental signals and novel methods to track and guide transplanted stem cells. A major complication encountered with stem cell therapies has been the failure of injected cells to engraft to target tissues. The application of nanotechnology to stem cell biology would be able to address those challenges. Combinations of stem cell therapy and nanotechnology in tissue engineering and regenerative medicine have achieved significant advances. These combinations allow nanotechnology to engineer scaffolds with various features to control stem cell fate decisions. Fabrication of Nano fiber cell scaffolds onto which stem cells can adhere and spread, forming a niche-like microenvironment which can guide stem cells to proceed to heal damaged tissues. In this paper, current and emergent approach based on stem cells in the field of liver tissue engineering is presented for specific application. The combination of stem cells and tissue engineering opens new perspectives in tissue regeneration for stem cell therapy because of the potential to control stem cell behavior with the physical and chemical characteristics of the engineered scaffold environment.

Stem-Cell-Based Tumorigenesis in Adult Drosophila.

PubMed

Hou, S X; Singh, S R

2017-01-01

Recent studies suggest that a small subset of cells within a tumor, the so-called cancer stem cells (CSCs), are responsible for tumor propagation, relapse, and the eventual death of most cancer patients. CSCs may derive from a few tumor-initiating cells, which are either transformed normal stem cells or reprogrammed differentiated cells after acquiring initial cancer-causing mutations. CSCs and normal stem cells share some properties, but CSCs differ from normal stem cells in their tumorigenic ability. Notably, CSCs are usually resistant to chemo- and radiation therapies. Despite the apparent roles of CSCs in human cancers, the biology underlying their behaviors remains poorly understood. Over the past few years, studies in Drosophila have significantly contributed to this new frontier of cancer research. Here, we first review how stem-cell tumors are initiated and propagated in Drosophila, through niche appropriation in the posterior midgut and through stem-cell competition for niche occupancy in the testis. We then discuss the differences between normal and tumorigenic stem cells, revealed by studying Ras V12 -transformed stem-cell tumors in the Drosophila kidney. Finally, we review the biology behind therapy resistance, which has been elucidated through studies of stem-cell resistance and sensitivity to death inducers using female germline stem cells and intestinal stem cells of the posterior midgut. We expect that screens using adult Drosophila neoplastic stem-cell tumor models will be valuable for identifying novel and effective compounds for treating human cancers. © 2017 Elsevier Inc. All rights reserved.

Stem cells with potential to generate insulin producing cells in man.

PubMed

Zulewski, Henryk

2006-10-14

Replacement of insulin-producing cells represents an almost ideal treatment for patients with diabetes mellitus type 1. Transplantation of pancreatic islets of Langerhans--although successful in experienced centres--is limited by the lack of donor organs. Generation of insulin-producing cells from stem cells represents an attractive alternative. Stem cells with the potential to differentiate into insulin-producing cells include embryonic stem cells (ESC) as well as adult stem cells from various tissues including the pancreas, liver, central nervous system, bone marrow and adipose tissue. The use of human ESC is hampered by ethical concerns and the inability to create patient specific ESC with therapeutic cloning. Among adult stem cells mesenchymal stem cells appear to have a particular developmental plasticity ex vivo that include their ability to adopt a pancreatic endocrine phenotype. The present review summarises the current knowledge on the development of insulin-producing cells from stem cells with special emphasis on human mesenchymal stem cells isolated from the pancreas and adipose tissue.

Stem cells with potential to generate insulin-producing cells in man.

PubMed

Zulewski, Henryk

2007-03-02

Replacement of insulin-producing cells represents an almost ideal treatment for patients with diabetes mellitus type 1. Transplantation of pancreatic islets of Langerhans--although successful in experienced centres--is limited by the lack of donor organs. Generation of insulin-producing cells from stem cells represents an attractive alternative. Stem cells with the potential to differentiate into insulin-producing cells include embryonic stem cells (ESC) as well as adult stem cells from various tissues including the pancreas, liver, central nervous system, bone marrow and adipose tissue. The use of human ESC is hampered by ethical concerns and the inability to create patient specific ESC with therapeutic cloning. Among adult stem cells mesenchymal stem cells appear to have a particular developmental plasticity ex vivo that include their ability to adopt a pancreatic endocrine phenotype. The present review summarises the current knowledge on the development of insulin-producing cells from stem cells with special emphasis on human mesenchymal stem cells isolated from the pancreas and adipose tissue.

Mechanical forces direct stem cell behaviour in development and regeneration

PubMed Central

Vining, Kyle H.; Mooney, David J.

2018-01-01

Stem cells and their local microenvironment, or niche, communicate through mechanical, cues to regulate cell fate and cell behaviour, and to guide developmental processes. During embryonic development, mechanical forces are involved in patterning and organogenesis. The physical environment of pluripotent stem cells regulates their differentiation and self-renewal. Mechanical and physical cues are also important in adult tissues, where adult stem cells require physical interactions with the extracellular matrix to maintain their potency. In vitro, synthetic models of the stem cell niche can be used to precisely control and manipulate the biophysical and biochemical properties of the stem cell microenvironment and examine how the mode and magnitude of mechanical cues, such as matrix stiffness or applied forces, direct stem cell differentiation and function. Fundamental insights on the mechanobiology of stem cells also inform the design of artificial niches to support stem cells for regenerative therapies. PMID:29115301

Recent Advances towards the Clinical Application of Stem Cells for Retinal Regeneration

PubMed Central

Becker, Silke; Jayaram, Hari; Limb, G. Astrid

2012-01-01

Retinal degenerative diseases constitute a major cause of irreversible blindness in the world. Stem cell-based therapies offer hope for these patients at risk of or suffering from blindness due to the deterioration of the neural retina. Various sources of stem cells are currently being investigated, ranging from human embryonic stem cells to adult-derived induced pluripotent stem cells as well as human Müller stem cells, with the first clinical trials to investigate the safety and tolerability of human embryonic stem cell-derived retinal pigment epithelium cells having recently commenced. This review aims to summarize the latest advances in the development of stem cell strategies for the replacement of retinal neurons and their supportive cells, the retinal pigment epithelium (RPE) affected by retinal degenerative conditions. Particular emphasis will be given to the advances in stem cell transplantation and the challenges associated with their translation into clinical practice. PMID:24710533

Stem-Cell Therapy Advances in China.

PubMed

Hu, Lei; Zhao, Bin; Wang, Songlin

2018-02-01

Stem-cell therapy is a promising method for treating patients with a wide range of diseases and injuries. Increasing government funding of scientific research has promoted rapid developments in stem-cell research in China, as evidenced by the substantial increase in the number and quality of publications in the past 5 years. Multiple high-quality studies have been performed in China that concern cell reprogramming, stem-cell homeostasis, gene modifications, and immunomodulation. The number of translation studies, including basic and preclinical investigations, has also increased. Around 100 stem-cell banks have been established in China, 10 stem-cell drugs are currently in the approval process, and >400 stem cell-based clinical trials are currently registered in China. With continued state funding, advanced biotechnical support, and the development of regulatory standards for the clinical application of stem cells, further innovations are expected that will lead to a boom in stem-cell therapies. This review highlights recent achievements in stem-cell research in China and discusses future prospects.

New insights into mechanisms of stem cell daughter fate determination in regenerative tissues.

PubMed

Sada, Aiko; Tumbar, Tudorita

2013-01-01

Stem cells can self-renew and differentiate over extended periods of time. Understanding how stem cells acquire their fates is a central question in stem cell biology. Early work in Drosophila germ line and neuroblast showed that fate choice is achieved by strict asymmetric divisions that can generate each time one stem and one differentiated cell. More recent work suggests that during homeostasis, some stem cells can divide symmetrically to generate two differentiated cells or two identical stem cells to compensate for stem cell loss that occurred by direct differentiation or apoptosis. The interplay of all these factors ensures constant tissue regeneration and the maintenance of stem cell pool size. This interplay can be modeled as a population-deterministic dynamics that, at least in some systems, may be described as stochastic behavior. Here, we overview recent progress made on the characterization of stem cell dynamics in regenerative tissues. Copyright © 2013 Elsevier Inc. All rights reserved.

Selection of Phage Display Peptides Targeting Human Pluripotent Stem Cell-Derived Progenitor Cell Lines.

PubMed

Bignone, Paola A; Krupa, Rachel A; West, Michael D; Larocca, David

2016-01-01

The ability of human pluripotent stem cells (hPS) to both self-renew and differentiate into virtually any cell type makes them a promising source of cells for cell-based regenerative therapies. However, stem cell identity, purity, and scalability remain formidable challenges that need to be overcome for translation of pluripotent stem cell research into clinical applications. Directed differentiation from hPS cells is inefficient and residual contamination with pluripotent cells that have the potential to form tumors remains problematic. The derivation of scalable (self-renewing) embryonic progenitor stem cell lines offers a solution because they are well defined and clonally pure. Clonally pure progenitor stem cell lines also provide a means for identifying cell surface targeting reagents that are useful for identification, tracking, and repeated derivation of the corresponding progenitor stem cell types from additional hPS cell sources. Such stem cell targeting reagents can then be applied to the manufacture of genetically diverse banks of human embryonic progenitor cell lines for drug screening, disease modeling, and cell therapy. Here we present methods to identify human embryonic progenitor stem cell targeting peptides by selection of phage display libraries on clonal embryonic progenitor cell lines and demonstrate their use for targeting quantum dots (Qdots) for stem cell labeling.

Extinction models for cancer stem cell therapy

PubMed Central

Sehl, Mary; Zhou, Hua; Sinsheimer, Janet S.; Lange, Kenneth L.

2012-01-01

Cells with stem cell-like properties are now viewed as initiating and sustaining many cancers. This suggests that cancer can be cured by driving these cancer stem cells to extinction. The problem with this strategy is that ordinary stem cells are apt to be killed in the process. This paper sets bounds on the killing differential (difference between death rates of cancer stem cells and normal stem cells) that must exist for the survival of an adequate number of normal stem cells. Our main tools are birth–death Markov chains in continuous time. In this framework, we investigate the extinction times of cancer stem cells and normal stem cells. Application of extreme value theory from mathematical statistics yields an accurate asymptotic distribution and corresponding moments for both extinction times. We compare these distributions for the two cell populations as a function of the killing rates. Perhaps a more telling comparison involves the number of normal stem cells NH at the extinction time of the cancer stem cells. Conditioning on the asymptotic time to extinction of the cancer stem cells allows us to calculate the asymptotic mean and variance of NH. The full distribution of NH can be retrieved by the finite Fourier transform and, in some parameter regimes, by an eigenfunction expansion. Finally, we discuss the impact of quiescence (the resting state) on stem cell dynamics. Quiescence can act as a sanctuary for cancer stem cells and imperils the proposed therapy. We approach the complication of quiescence via multitype branching process models and stochastic simulation. Improvements to the τ-leaping method of stochastic simulation make it a versatile tool in this context. We conclude that the proposed therapy must target quiescent cancer stem cells as well as actively dividing cancer stem cells. The current cancer models demonstrate the virtue of attacking the same quantitative questions from a variety of modeling, mathematical, and computational perspectives. PMID:22001354

Extinction models for cancer stem cell therapy.

PubMed

Sehl, Mary; Zhou, Hua; Sinsheimer, Janet S; Lange, Kenneth L

2011-12-01

Cells with stem cell-like properties are now viewed as initiating and sustaining many cancers. This suggests that cancer can be cured by driving these cancer stem cells to extinction. The problem with this strategy is that ordinary stem cells are apt to be killed in the process. This paper sets bounds on the killing differential (difference between death rates of cancer stem cells and normal stem cells) that must exist for the survival of an adequate number of normal stem cells. Our main tools are birth-death Markov chains in continuous time. In this framework, we investigate the extinction times of cancer stem cells and normal stem cells. Application of extreme value theory from mathematical statistics yields an accurate asymptotic distribution and corresponding moments for both extinction times. We compare these distributions for the two cell populations as a function of the killing rates. Perhaps a more telling comparison involves the number of normal stem cells NH at the extinction time of the cancer stem cells. Conditioning on the asymptotic time to extinction of the cancer stem cells allows us to calculate the asymptotic mean and variance of NH. The full distribution of NH can be retrieved by the finite Fourier transform and, in some parameter regimes, by an eigenfunction expansion. Finally, we discuss the impact of quiescence (the resting state) on stem cell dynamics. Quiescence can act as a sanctuary for cancer stem cells and imperils the proposed therapy. We approach the complication of quiescence via multitype branching process models and stochastic simulation. Improvements to the τ-leaping method of stochastic simulation make it a versatile tool in this context. We conclude that the proposed therapy must target quiescent cancer stem cells as well as actively dividing cancer stem cells. The current cancer models demonstrate the virtue of attacking the same quantitative questions from a variety of modeling, mathematical, and computational perspectives. Copyright © 2011 Elsevier Inc. All rights reserved.

Novel Combinatory Approaches to Repair Visual System after Optic Nerve Damage

DTIC Science & Technology

2014-09-01

Intravitreal Viral Treatment Outcome Measures PTEN/SOCS3f/f AAV-GFP (Control) RGC staining and axon tracing PTEN/SOCS3f/f AAV-Cre “ “ CHOP-/- AAV-XBP1...survival and axon regeneration using immunohistochemistry and axon tracing methods used in our previous studies. At 4 and 8 weeks after injury, retinas...the cell body. After peripheral nerve injury, phosphorylated (i.e., active) STAT3 is detected in the injured axons and later in the soma (Lee, Neitzel

Aging and stem cell therapy: AMPK as an applicable pharmacological target for rejuvenation of aged stem cells and achieving higher efficacy in stem cell therapy.

PubMed

Khorraminejad-Shirazi, Mohammadhossein; Farahmandnia, Mohammad; Kardeh, Bahareh; Estedlal, Alireza; Kardeh, Sina; Monabati, Ahmad

2017-10-19

In recent years, tissue regeneration has become a promising field for developing stem cell-based transplantation therapies for human patients. Adult stem cells are affected by the same aging mechanisms that involve somatic cells. One of the mechanisms involved in cellular aging is hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) and disruption of 5' adenosine monophosphate-activated protein kinase (AMPK). Aging of stem cells results in their impaired regenerative capacity and depletion of stem cell pools in adult tissue, which results in lower efficacy of stem cell therapy. By utilizing an effective therapeutic intervention for aged stem cells, stem cell therapy can become more promising for future application. mTORC1 inhibition is a practical approach to preserve the stem cell pool. In this article, we review the dynamic interaction between sirtuin (silent mating type information regulation 2 homolog) 1, AMPK, and mTORC1. We propose that using AMPK activators such as 5-aminoimidazole-4-carboxamide ribonucleotide, A769662, metformin, and oxidized nicotinamide adenine dinucleotide (NAD + ) are practical ways to be employed for achieving better optimized results in stem cell-based transplantation therapies. Copyright © 2017 King Faisal Specialist Hospital & Research Centre. Published by Elsevier B.V. All rights reserved.

Stemness of spermatogonial stem cells encapsulated in alginate hydrogel during cryopreservation.

PubMed

Pirnia, A; Parivar, K; Hemadi, M; Yaghmaei, P; Gholami, M

2017-06-01

This study investigated the effect of spermatogonial stem cell encapsulated in alginate hydrogel during cryopreservation, as cells were protected against damage during cryopreservation within the hydrogel. Spermatogonial stem cells were isolated from the testes of Balb/c mice pups (6 days old), purified in laminin-coated dishes and CD90.1 microbeads, encapsulated in alginate hydrogel and then cryopreserved. After thawing, cell viability and Spermatogonial stem cell (SSC) colony diameter were evaluated. After RNA was isolated and cDNA was synthesised, the expression of stemness genes was considered using RT real-time PCR. Finally, spermatogonial stem cells labelled with BrdU were transplanted to busulfan azoospermic mouse models. Lin28a and Sall4 genes were significantly upregulated after cryopreservation in alginate hydrogel. However, cell viability was significantly decreased. The diameter of colonies consisting of spermatogonial stem cells freeze-thawed in alginate microbeads showed no significant difference with fresh spermatogonial stem cells and the control group. The injection of freeze-thawed spermatogonial stem cells encapsulated in alginate hydrogel resulted in spermatogenesis recovery. Alginate mimics the extracellular matrices (ECM) for spermatogonial stem cells; therefore, it can support stemness potential during the cell cryopreservation process and restart spermatogenesis after transplantation. © 2016 Blackwell Verlag GmbH.

Normal and cancer mammary stem cells evade interferon-induced constraint through the miR-199a-LCOR Axis

PubMed Central

Celià-Terrassa, Toni; Liu, Daniel; Choudhury, Abrar; Hang, Xiang; Wei, Yong; Zamalloa, Jose; Alfaro-Aco, Raymundo; Chakrabarti, Rumela; Jiang, Yi-Zhou; Koh, Bong Ihn; Smith, Heath; DeCoste, Christina; Li, Jun-Jing; Shao, Zhi-Ming; Kang, Yibin

2017-01-01

Tumor-initiating cells (TICs), or cancer stem cells (CSC), possess stem cell-like properties observed in normal adult tissue stem cells. Normal and cancerous stem cells may therefore share regulatory mechanisms for maintaining self-renewing capacity and resisting differentiation elicited by cell-intrinsic or microenvironmental cues. Here, we show that miR-199a promotes stem cell properties in mammary stem cells (MaSCs) and breast CSCs by directly repressing nuclear receptor corepressor LCOR, which primes interferon (IFN) responses. Elevated miR-199a expression in stem cell-enriched populations protects normal and malignant stem-like cells from differentiation and senescence induced by IFNs that are produced by epithelial and immune cells in the mammary gland. Importantly, the miR-199a-LCOR-IFN axis is activated in poorly differentiated ER− breast tumors, functionally promotes tumor initiation and metastasis, and is associated with poor clinical outcome. Our study therefore reveals a common mechanism shared by normal and malignant stem cells to protect them from suppressive immune cytokine signaling. PMID:28530657

The Role of Epithelial-Mesenchymal Transition in the Formation of Normal and Neoplastic Mammary Epithelial Stem Cells

DTIC Science & Technology

2011-09-01

separating stem cell and non- stem cell populations of normal and breast cancer cells and identified EMT transcription factors most likely involved in... stem cell biology. Preliminary results directly demonstrate that transient induction of EMT increases the number of mammary epithelial stem cells...EMT and entrance into a stem - cell state. The outcome of these experiments holds important implications for the mechanisms controlling the formation of

Role of the Stem Cell Niche in Hormone-Induced Tumorigenesis in Fetal Mouse Mammary Epithelium

DTIC Science & Technology

2005-08-01

responsive, self renewing and pluripotent. A structure specialized to contain and regulate stem cell activity has been structurally and molecularly...described in Drosophila and some mammalian tissues. The structure, the stem cell niche, functions to 1) shield the stem cell from the burden of incoming...directing stem cell renewal and maturation, 3) prevent stem cells from wandering through the tissue and producing new cells inappropriately, 4) prevent

The Effect of Laser Irradiation on Adipose Derived Stem Cell Proliferation and Differentiation

NASA Astrophysics Data System (ADS)

Abrahamse, H.; de Villiers, J.; Mvula, B.

2009-06-01

There are two fundamental types of stem cells: Embryonic Stem cells and Adult Stem cells. Adult Stem cells have a more restricted potential and can usually differentiate into a few different cell types. In the body these cells facilitate the replacement or repair of damaged or diseased cells in organs. Low intensity laser irradiation was shown to increase stem cell migration and stimulate proliferation and it is thought that treatment of these cells with laser irradiation may increase the stem cell harvest and have a positive effect on the viability and proliferation. Our research is aimed at determining the effect of laser irradiation on differentiation of Adipose Derived Stem Cells (ADSCs) into different cell types using a diode laser with a wavelength of 636 nm and at 5 J/cm2. Confirmation of stem cell characteristics and well as subsequent differentiation were assessed using Western blot analysis and cellular morphology supported by fluorescent live cell imaging. Functionality of subsequent differentiated cells was confirmed by measuring adenosine triphosphate (ATP) production and cell viability.

Alpha-fetoprotein, stem cells and cancer: how study of the production of alpha-fetoprotein during chemical hepatocarcinogenesis led to reaffirmation of the stem cell theory of cancer.

PubMed

Sell, Stewart

2008-01-01

Identification of the cells in the liver that produce alpha-fetoprotein during development, in response to liver injury and during the early stages of chemical hepatocarcinogenesis led to the conclusion that maturation arrest of liver-determined tissue stem cells was the cellular process that gives rise to hepatocellular carcinomas. When the cellular changes in these processes were compared to that of the formation of teratocarcinomas, the hypothesis arose that all cancers arise from maturation arrest of tissue-determined stem cells. This was essentially a reinterpretation of the embryonal rest theory of cancer whereby tissue stem cells take the role of embryonal rests. A corollary of the stem cell theory of the origin of cancer is that cancers contain the same functional cell populations as normal tissues: stem cells, transit-amplifying cells and mature cells. Cancer stem cells retain the essential feature of normal stem cells: the ability to self-renew. Growth of cancers is due to continued proliferation of cancer transit-amplifying cells that do not differentiate to mature cells (maturation arrest). On the other hand, cancer stem cells generally divide very rarely and contribute little to tumor growth. However, the presence of cancer stem cells in tumors is believed to be responsible for the properties of immortalization, transplantability and resistance to therapy characteristic of cancers. Current therapies for cancer (chemotherapy, radiotherapy, antiangiogenesis and differentiation therapy) are directed against the cancer transit-amplifying cells. When these therapies are discontinued, the cancer reforms from the cancer stem cells. Therapy directed toward interruption of the cell signaling pathways that maintain cancer stem cells could lead to new modalities to the prevention of regrowth of the cancer. Copyright 2008 S. Karger AG, Basel.

ALPHA-FETOPROTEIN (AFP), STEM CELLS, AND CANCER: HOW STUDY OF THE PRODUCTION OF AFP DURING CHEMICAL HEPATOCARCINOGENESIS LED TO REAFFIRMATION OF THE STEM CELL THEORY OF CANCER

PubMed Central

Sell, Stewart

2008-01-01

Identification of the cells in the liver that produce alpha-fetoprotein (AFP) during development, in response to liver injury, and during the early stages of chemical hepatocarcinogenesis led to the conclusion that maturation arrest of liver-determined tissue stem cells was the cellular process that gives rise to hepatocellular carcinomas (HCC). When the cellular changes in these processes were compared that of the formation of teratocarcinomas, the hypothesis arose that all cancers arise from maturation arrest of tissue determined stem cells. This was essentially a reinterpretation of the embryonal rest theory of cancer whereby tissue stem cells take the role of embryonal rests. A corollary of the stem cell theory of the origin of cancer is that cancers contain the same functional cell populations as do normal tissues: stem cells, transit-amplifying cells, and mature cells. Cancer stem cells retain the essential feature of normal stem cells: the ability to self-renew. Growth of cancers is due to continued proliferation of cancer transit-amplifying cells that do not differentiate to mature cells (maturation arrest). On the other hand, cancer stem cells generally divide very rarely and contribute little to tumor growth. However, the presence of cancer stem cells in tumors is believed to be responsible for the properties of immortalization, transplantability and resistance to therapy characteristic of cancers. Current therapies for cancer (chemotherapy, radiotherapy, anti-angiogenesis and differentiation therapy) are directed against the cancer transit amplifying cells. When these therapies are discontinued, the cancer re-forms from the cancer stem cells. Therapy directed toward interruption of the cell-signaling pathways that maintain cancer stem cells could lead to new modalities to the prevention of re-growth of the cancer. PMID:18612221

A Comparative Transcriptomic Analysis Reveals Conserved Features of Stem Cell Pluripotency in Planarians and Mammals

PubMed Central

Labbé, Roselyne M.; Irimia, Manuel; Currie, Ko W.; Lin, Alexander; Zhu, Shu Jun; Brown, David D.R.; Ross, Eric J.; Voisin, Veronique; Bader, Gary D.; Blencowe, Benjamin J.; Pearson, Bret J.

2014-01-01

Many long-lived species of animals require the function of adult stem cells throughout their lives. However, the transcriptomes of stem cells in invertebrates and vertebrates have not been compared, and consequently, ancestral regulatory circuits that control stem cell populations remain poorly defined. In this study, we have used data from high-throughput RNA sequencing to compare the transcriptomes of pluripotent adult stem cells from planarians with the transcriptomes of human and mouse pluripotent embryonic stem cells. From a stringently defined set of 4,432 orthologs shared between planarians, mice and humans, we identified 123 conserved genes that are ≥5-fold differentially expressed in stem cells from all three species. Guided by this gene set, we used RNAi screening in adult planarians to discover novel stem cell regulators, which we found to affect the stem cell-associated functions of tissue homeostasis, regeneration, and stem cell maintenance. Examples of genes that disrupted these processes included the orthologs of TBL3, PSD12, TTC27, and RACK1. From these analyses, we concluded that by comparing stem cell transcriptomes from diverse species, it is possible to uncover conserved factors that function in stem cell biology. These results provide insights into which genes comprised the ancestral circuitry underlying the control of stem cell self-renewal and pluripotency. PMID:22696458

Investigating the mincing method for isolation of adipose-derived stem cells from pregnant women fat.

PubMed

Li, Yuan-Sheng; Chen, Pao-Jen; Wu, Li-Wei; Chou, Pei-Wen; Sun, Li-Yi; Chiou, Tzyy-Wen

2018-02-01

The success of stem cell application in regenerative medicine, usually require a stable source of stem or progenitor cells. Fat tissue represents a good source of stem cells because it is rich in stem cells and there are fewer ethical issues related to the use of such stem cells, unlike embryonic stem cells. Therefore, there has been increased interest in adipose-derived stem cells (ADSCs) for tissue engineering applications. Here, we aim to provide an easy processing method for isolating adult stem cells from human adipose tissue harvested from the subcutaneous fat of the abdominal wall during gynecologic surgery. We used a homogenizer to mince fat and compared the results with those obtained from the traditional cut method involving a sterile scalpel and forceps. Our results showed that our method provides another stable and quality source of stem cells that could be used in cases with a large quantity of fat. Furthermore, we found that pregnancy adipose-derived stem cells (P-ADSCs) could be maintained in vitro for extended periods with a stable population doubling and low senescence levels. P-ADSCs could also differentiate in vitro into adipogenic, osteogenic, chondrogenic, and insulin-producing cells in the presence of lineage-specific induction factors. In conclusion, like human lipoaspirates, adipose tissues obtained from pregnant women contain multipotent cells with better proliferation and showed great promise for use in both stem cell banking studies as well as in stem cell therapy.

Gremlin 1 Identifies a Skeletal Stem Cell with Bone, Cartilage, and Reticular Stromal Potential

PubMed Central

Worthley, Daniel L.; Churchill, Michael; Compton, Jocelyn T.; Tailor, Yagnesh; Rao, Meenakshi; Si, Yiling; Levin, Daniel; Schwartz, Matthew G.; Uygur, Aysu; Hayakawa, Yoku; Gross, Stefanie; Renz, Bernhard W.; Setlik, Wanda; Martinez, Ashley N.; Chen, Xiaowei; Nizami, Saqib; Lee, Heon Goo; Kang, H. Paco; Caldwell, Jon-Michael; Asfaha, Samuel; Westphalen, C. Benedikt; Graham, Trevor; Jin, Guangchun; Nagar, Karan; Wang, Hongshan; Kheirbek, Mazen A.; Kolhe, Alka; Carpenter, Jared; Glaire, Mark; Nair, Abhinav; Renders, Simon; Manieri, Nicholas; Muthupalani, Sureshkumar; Fox, James G.; Reichert, Maximilian; Giraud, Andrew S.; Schwabe, Robert F.; Pradere, Jean-Phillipe; Walton, Katherine; Prakash, Ajay; Gumucio, Deborah; Rustgi, Anil K.; Stappenbeck, Thaddeus S.; Friedman, Richard A.; Gershon, Michael D.; Sims, Peter; Grikscheit, Tracy; Lee, Francis Y.; Karsenty, Gerard; Mukherjee, Siddhartha; Wang, Timothy C.

2014-01-01

The stem cells that maintain and repair the postnatal skeleton remain undefined. One model suggests that perisinusoidal mesenchymal stem cells (MSCs) give rise to osteoblasts, chondrocytes, marrow stromal cells, and adipocytes, although the existence of these cells has not been proven through fate-mapping experiments. We demonstrate here that expression of the bone morphogenetic protein (BMP) antagonist gremlin 1 defines a population of osteochondroreticular (OCR) stem cells in the bone marrow. OCR stem cells self-renew and generate osteoblasts, chondrocytes, and reticular marrow stromal cells, but not adipocytes. OCR stem cells are concentrated within the metaphysis of long bones not in the perisinusoidal space and are needed for bone development, bone remodeling, and fracture repair. Grem1 expression also identifies intestinal reticular stem cells (iRSCs) that are cells of origin for the periepithelial intestinal mesenchymal sheath. Grem1 expression identifies distinct connective tissue stem cells in both the bone (OCR stem cells) and the intestine (iRSCs). PMID:25594183

Biochemistry of epidermal stem cells.

PubMed

Eckert, Richard L; Adhikary, Gautam; Balasubramanian, Sivaprakasam; Rorke, Ellen A; Vemuri, Mohan C; Boucher, Shayne E; Bickenbach, Jackie R; Kerr, Candace

2013-02-01

The epidermis is an important protective barrier that is essential for maintenance of life. Maintaining this barrier requires continuous cell proliferation and differentiation. Moreover, these processes must be balanced to produce a normal epidermis. The stem cells of the epidermis reside in specific locations in the basal epidermis, hair follicle and sebaceous glands and these cells are responsible for replenishment of this tissue. A great deal of effort has gone into identifying protein epitopes that mark stem cells, in identifying stem cell niche locations, and in understanding how stem cell populations are related. We discuss these studies as they apply to understanding normal epidermal homeostasis and skin cancer. An assortment of stem cell markers have been identified that permit assignment of stem cells to specific regions of the epidermis, and progress has been made in understanding the role of these cells in normal epidermal homeostasis and in conditions of tissue stress. A key finding is the multiple stem cell populations exist in epidermis that give rise to different structures, and that multiple stem cell types may contribute to repair in damaged epidermis. Understanding epidermal stem cell biology is likely to lead to important therapies for treating skin diseases and cancer, and will also contribute to our understanding of stem cells in other systems. This article is part of a Special Issue entitled Biochemistry of Stem Cells. Copyright © 2012 Elsevier B.V. All rights reserved.

Basics and applications of stem cells in the pancreas.

PubMed

Sekine, Keisuke; Taniguchi, Hideki

2012-11-01

Enormous efforts have been made to establish pancreatic stem/progenitor cells as a source for regenerative medicine for the treatment of diabetes mellitus. In recent years, it has been recognized that the self-renewal of beta cells is the dominant process involved in postnatal beta-cell regeneration and expansion. Nevertheless, several in-vitro studies have suggested that ductal or as yet unidentified cells are candidates for pancreatic stem/progenitor cells that can differentiate into multilineage cells, including insulin(+) cells. The question remains as to whether beta cells are generated postnatally from stem/progenitor cells other than pre-existing beta cells. Furthermore, mutated pancreatic stem cells are considered to be prospective candidates for cancer stem cells or tumor-initiating cells. This review highlights recent progress in pancreatic stem/progenitor cell research.

Ablation of proliferating neural stem cells during early life is sufficient to reduce adult hippocampal neurogenesis.

PubMed

Youssef, Mary; Krish, Varsha S; Kirshenbaum, Greer S; Atsak, Piray; Lass, Tamara J; Lieberman, Sophie R; Leonardo, E David; Dranovsky, Alex

2018-05-09

Environmental exposures during early life, but not during adolescence or adulthood, lead to persistent reductions in neurogenesis in the adult hippocampal dentate gyrus (DG). The mechanisms by which early life exposures lead to long-term deficits in neurogenesis remain unclear. Here, we investigated whether targeted ablation of dividing neural stem cells during early life is sufficient to produce long-term decreases in DG neurogenesis. Having previously found that the stem cell lineage is resistant to long-term effects of transient ablation of dividing stem cells during adolescence or adulthood (Kirshenbaum et al., 2014), we used a similar pharmacogenetic approach to target dividing neural stem cells for elimination during early life periods sensitive to environmental insults. We then assessed the Nestin stem cell lineage in adulthood. We found that the adult neural stem cell reservoir was depleted following ablation during the first postnatal week, when stem cells were highly proliferative, but not during the third postnatal week, when stem cells were more quiescent. Remarkably, ablating proliferating stem cells during either the first or third postnatal week led to reduced adult neurogenesis out of proportion to the changes in the stem cell pool, indicating a disruption of the stem cell function or niche following stem cell ablation in early life. These results highlight the first three postnatal weeks as a series of sensitive periods during which elimination of dividing stem cells leads to lasting alterations in adult DG neurogenesis and stem cell function. These findings contribute to our understanding of the relationship between DG development and adult neurogenesis, as well as suggest a possible mechanism by which early life experiences may lead to lasting deficits in adult hippocampal neurogenesis. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

State performance in pluripotent and adult stem cell research, 2009-2016.

PubMed

Surani, Sana H; Levine, Aaron D

2018-04-01

To examine how the geographic distribution of pluripotent and adult stem cell research publications within the USA differs from other areas of biomedical research. Publication count data for pluripotent stem cell research, adult stem cell research and a comparison group representative of biomedical research more broadly were collected and analyzed for each US state from 2009 to 2016. The distribution of pluripotent stem cell research differed from the other fields with overperformance in pluripotent stem cell research observed in California, as well as Wisconsin, Massachusetts, Maryland and Connecticut. Our analysis suggests that permissive state stem cell policy may be one of the several factors contributing to strong state performance in pluripotent stem cell research.

Stem cell clinics online: the direct-to-consumer portrayal of stem cell medicine.

PubMed

Lau, Darren; Ogbogu, Ubaka; Taylor, Benjamin; Stafinski, Tania; Menon, Devidas; Caulfield, Timothy

2008-12-04

Despite the immature state of stem cell medicine, patients are seeking and accessing putative stem cell therapies in an "early market" in which direct-to-consumer advertising via the internet likely plays an important role. We analyzed stem cell clinic websites and appraised the relevant published clinical evidence of stem cell therapies to address three questions about the direct-to-consumer portrayal of stem cell medicine in this early market: What sorts of therapies are being offered? How are they portrayed? Is there clinical evidence to support the use of these therapies? We found that the portrayal of stem cell medicine on provider websites is optimistic and unsubstantiated by peer-reviewed literature.

Effects of Telomerase and Telomere Length on Epidermal Stem Cell Behavior

NASA Astrophysics Data System (ADS)

Flores, Ignacio; Cayuela, María L.; Blasco, María A.

2005-08-01

A key process in organ homeostasis is the mobilization of stem cells out of their niches. We show through analysis of mouse models that telomere length, as well as the catalytic component of telomerase, Tert, are critical determinants in the mobilization of epidermal stem cells. Telomere shortening inhibited mobilization of stem cells out of their niche, impaired hair growth, and resulted in suppression of stem cell proliferative capacity in vitro. In contrast, Tert overexpression in the absence of changes in telomere length promoted stem cell mobilization, hair growth, and stem cell proliferation in vitro. The effects of telomeres and telomerase on stem cell biology anticipate their role in cancer and aging.

Comparison of antifungal efficacies of moxifloxacin, liposomal amphotericin B, and combination treatment in experimental Candida albicans endophthalmitis in rabbits.

PubMed

Deren, Yudum Tiftikcioğlu; Ozdek, Sengül; Kalkanci, Ayşe; Akyürek, Nalan; Hasanreisoğlu, Berati

2010-01-01

The goal of this study was to compare in vitro and in vivo efficacy of moxifloxacin and liposomal amphotericin B (Amp-B) monotherapies and combination treatment against Candida albicans in an exogenous endophthalmitis model in rabbit eyes. Microplate dilution tests and checkerboard analysis were performed to detect in vitro efficacies. Endophthalmitis was induced by intravitreal injection of C. albicans in 40 rabbit eyes with simultaneous intravitreal drug injection according to prophylactic treatment groups. Group 1 (control group) received 0.1 mL of balanced salt solution, group 2 (moxi group) 100 microg moxifloxacin/0.1 mL, group 3 (Amp-B group) 10 microg liposomal Amp-B/0.1 mL, and group 4 (combi group) both 100 microg moxifloxacin/0.1 mL [DOSAGE ERROR CORRECTED] and 10 microg liposomal Amp-B/0.05 mL intravitreally. Clinical examination, quantitative analysis of microorganisms, and histopathologic examination were performed as in vivo studies. The minimum inhibitory concentration of liposomal Amp-B against C. albicans was found to be 1 microg/mL. Moxifloxacin showed no inhibition of in vitro C. albicans growth. The minimum inhibitory concentration values of liposomal Amp-B for C. albicans were reduced two- to eightfold with increasing concentrations of moxifloxacin in vitro. In vivo, there was no C. albicans growth in the combi group (zero of eight eyes), whereas three eyes (37.5%) showed growth in the Amp-B group. Vitreous inflammation, retinal detachment, focal retinal necrosis, and outer nuclear layer loss were found to be lower in the moxi group compared with the control group. Ganglion cell and inner nuclear layer loss was observed in all eyes (100%) in both the moxi and combi groups, whereas only in 25% (two of eight eyes) in the Amp-B group. Moxifloxacin strongly augments the efficacy of liposomal Amp-B against C. albicans in vitro, although it has no in vitro antifungal activity when used alone. It is interesting that we found a synergistic effect for in vitro tests but failed to demonstrate it in vivo. When 100 microg moxifloxacin/0.1 mL is given intravitreally, it has some toxic effects that are limited to the inner retinal layers.

Prospects for neural stem cell-based therapies for neurological diseases.

PubMed

Imitola, Jaime

2007-10-01

Neural stem and progenitor cells have great potential for the treatment of neurological disorders. However, many obstacles remain to translate this field to the patient's bedside, including rationales for using neural stem cells in individual neurological disorders; the challenges of neural stem cell biology; and the caveats of current strategies of isolation and culturing neural precursors. Addressing these challenges is critical for the translation of neural stem cell biology to the clinic. Recent work using neural stem cells has yielded novel biologic concepts such as the importance of the reciprocal interaction between neural stem cells and the neurodegenerative environment. The prospect of using transplants of neural stem cells and progenitors to treat neurological diseases requires a better understanding of the molecular mechanisms of both neural stem cell behavior in experimental models and the intrinsic repair capacity of the injured brain.

Impact of genomic damage and ageing on stem cell function

PubMed Central

Behrens, Axel; van Deursen, Jan M.; Rudolph, K. Lenhard; Schumacher, Björn

2014-01-01

Impairment of stem cell function contributes to the progressive deterioration of tissue maintenance and repair with ageing. Evidence is mounting that age-dependent accumulation of DNA damage in both stem cells and cells that comprise the stem cell microenvironment are partly responsible for stem cell dysfunction with ageing. Here, we review the impact of the various types of DNA damage that accumulate with ageing on stem cell functionality, as well as the development of cancer. We discuss DNA-damage-induced cell intrinsic and extrinsic alterations that influence these processes, and review recent advances in understanding systemic adjustments to DNA damage and how they affect stem cells. PMID:24576896

Lgr proteins in epithelial stem cell biology.

PubMed

Barker, Nick; Tan, Shawna; Clevers, Hans

2013-06-01

The ultimate success of global efforts to exploit adult stem cells for regenerative medicine will depend heavily on the availability of robust, highly selective stem cell surface markers that facilitate the isolation of stem cells from human tissues. Any subsequent expansion or manipulation of isolated stem cells will also require an intimate knowledge of the mechanisms that regulate these cells, to ensure maintenance of their regenerative capacities and to minimize the risk of introducing undesirable growth traits that could pose health risks for patients. A subclass of leucine-rich repeat-containing G-protein-coupled receptor (Lgr) proteins has recently gained prominence as adult stem cell markers with crucial roles in maintaining stem cell functions. Here, we discuss the major impact that their discovery has had on our understanding of adult stem cell biology in various self-renewing tissues and in accelerating progress towards the development of effective stem cell therapies.

Nanotechnology in the regulation of stem cell behavior

NASA Astrophysics Data System (ADS)

Wu, King-Chuen; Tseng, Ching-Li; Wu, Chi-Chang; Kao, Feng-Chen; Tu, Yuan-Kun; So, Edmund C.; Wang, Yang-Kao

2013-10-01

Stem cells are known for their potential to repair damaged tissues. The adhesion, growth and differentiation of stem cells are likely controlled by the surrounding microenvironment which contains both chemical and physical cues. Physical cues in the microenvironment, for example, nanotopography, were shown to play important roles in stem cell fate decisions. Thus, controlling stem cell behavior by nanoscale topography has become an important issue in stem cell biology. Nanotechnology has emerged as a new exciting field and research from this field has greatly advanced. Nanotechnology allows the manipulation of sophisticated surfaces/scaffolds which can mimic the cellular environment for regulating cellular behaviors. Thus, we summarize recent studies on nanotechnology with applications to stem cell biology, including the regulation of stem cell adhesion, growth, differentiation, tracking and imaging. Understanding the interactions of nanomaterials with stem cells may provide the knowledge to apply to cell-scaffold combinations in tissue engineering and regenerative medicine.

Characterization of Amniotic Stem Cells

PubMed Central

Koike, Chika; Zhou, Kaixuan; Takeda, Yuji; Fathy, Moustafa; Okabe, Motonori; Yoshida, Toshiko; Nakamura, Yukio; Kato, Yukio

2014-01-01

Abstract The amnion membrane is developed from embryo-derived cells, and amniotic cells have been shown to exhibit multidifferentiation potential. These cells represent a desirable source for stem cells for a variety of reasons. However, to date very few molecular analyses of amnion-derived cells have been reported, and efficient markers for isolating the stem cells remain unclear. This paper assesses the characterization of amnion-derived cells as stem cells by examining stemness marker expressions for amnion-derived epithelial cells and mesenchymal cells by flow cytometry, immunocytochemistry, and quantitative PCR. Flow cytometry revealed that amnion epithelial cells expressed CD133, CD 271, and TRA-1-60, whereas mecenchymal cells expressed CD44, CD73, CD90, and CD105. Immunohistochemistry showed that both cells expressed the stemness markers Oct3/4, Sox2, Klf4, and SSEA4. Stemness genes' expression in amnion epithelial cells, mesenchymal cells, fibroblast, bone marrow–derived mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs) was compared by quantitative reverse-transcription polymerase chain reaction (RT-PCR). Amnion-derived epithelial cells and mesenchymal cells expressed Oct3/4, Nanog, and Klf4 more than bone marrow–derived MSCs. The sorted TRA1-60–positive cells expressed Oct3/4, Nanog, and Klf4 more than unsorted cells or TRA1-60–negative cells. TRA1-60 can be a marker for isolating amnion epithelial stem cells. PMID:25068631

Electroporation of the Testis

NASA Astrophysics Data System (ADS)

Yomogida, Kentaro

The mature mammalian testis is a marvelous organ that produces numerous sperm cells during its reproductive phase. This biologically significant process consists of three steps: stem cell self-renewal and differentiation, meiosis and genetic recombination, and haploid cell morphogenesis into sperm (Russell et al., 1990). The first step provides a good model for investigating the molecular mechanism of stem cell regulation. Currently, the mechanism underlying sperm cell production is a very exciting topic in regenerative medicine (Lensch et al. 2007; Okita et al., 2007). The spermatogonial stem cell system has several advantages, including the easy histological identification of stem cells (Russell et al., 1990), a clear relationship between stem cells and the supporting Sertoli cells, which provide a stem cell niche (Tadokoro et al., 2002; Yomogida et al., 2003), and a transplantation assay for stem cell activity (Oatley & Brinster, 2006). Although germline stem (GS) cells derived from the gonocytes in newborn testis constitute a suitable in vitro system for investigating the properties of spermatogonial stem cells (Kanatsu-Shinohara et al., 2003, 2004), studies using living mammalian testes continue to provide information regarding the roles of the stem cell niche. In vivo electroporation of the supporting cells in the testis will expand our ability to study it.

Current applications of human pluripotent stem cells: possibilities and challenges.

PubMed

Ho, Pai-Jiun; Yen, Men-Luh; Yet, Shaw-Fang; Yen, B Linju

2012-01-01

Stem cells are self-renewable cells with the differentiation capacity to develop into somatic cells with biological functions. This ability to sustain a renewable source of multi- and/or pluripotential differentiation has brought new hope to the field of regenerative medicine in terms of cell therapy and tissue engineering. Moreover, stem cells are invaluable tools as in vitro models for studying diverse fields, from basic scientific questions such as developmental processes and lineage commitment, to practical application including drug screening and testing. The stem cells with widest differentiation potential are pluripotent stem cells (PSCs), which are rare cells with the ability to generate somatic cells from all three germ layers. PSCs are considered the most optimal choice for therapeutic potential of stem cells, bringing new impetus to the field of regenerative medicine. In this article, we discuss the therapeutic potential of human PSCs (hPSCs) including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), reviewing the current preclinical and clinical data using these stem cells. We describe the classification of different sources of hPSCs, ongoing research, and currently encountered clinical obstacles of these novel and versatile human stem cells.

Monolayered mesenchymal stem cells repair scarred myocardium after myocardial infarction.

PubMed

Miyahara, Yoshinori; Nagaya, Noritoshi; Kataoka, Masaharu; Yanagawa, Bobby; Tanaka, Koichi; Hao, Hiroyuki; Ishino, Kozo; Ishida, Hideyuki; Shimizu, Tatsuya; Kangawa, Kenji; Sano, Shunji; Okano, Teruo; Kitamura, Soichiro; Mori, Hidezo

2006-04-01

Mesenchymal stem cells are multipotent cells that can differentiate into cardiomyocytes and vascular endothelial cells. Here we show, using cell sheet technology, that monolayered mesenchymal stem cells have multipotent and self-propagating properties after transplantation into infarcted rat hearts. We cultured adipose tissue-derived mesenchymal stem cells characterized by flow cytometry using temperature-responsive culture dishes. Four weeks after coronary ligation, we transplanted the monolayered mesenchymal stem cells onto the scarred myocardium. After transplantation, the engrafted sheet gradually grew to form a thick stratum that included newly formed vessels, undifferentiated cells and few cardiomyocytes. The mesenchymal stem cell sheet also acted through paracrine pathways to trigger angiogenesis. Unlike a fibroblast cell sheet, the monolayered mesenchymal stem cells reversed wall thinning in the scar area and improved cardiac function in rats with myocardial infarction. Thus, transplantation of monolayered mesenchymal stem cells may be a new therapeutic strategy for cardiac tissue regeneration.

Genetic and epigenetic instability of stem cells.

PubMed

Rajamani, Karthyayani; Li, Yuan-Sheng; Hsieh, Dean-Kuo; Lin, Shinn-Zong; Harn, Horng-Jyh; Chiou, Tzyy-Wen

2014-01-01

Recently, research on stem cells has been receiving an increasing amount of attention, both for its advantages and disadvantages. Genetic and epigenetic instabilities among stem cells have been a recurring obstacle to progress in regenerative medicine using stem cells. Various reports have stated that these instabilities can transform stem cells when transferred in vivo and thus have the potential to develop tumors. Previous research has shown that various extrinsic and intrinsic factors can contribute to the stability of stem cells. The extrinsic factors include growth supplements, growth factors, oxygen tension, passage technique, and cryopreservation. Controlling these factors based on previous reports may assist researchers in developing strategies for the production and clinical application of "safe" stem cells. On the other hand, the intrinsic factors can be unpredictable and uncontrollable; therefore, to ensure the successful use of stem cells in regenerative medicine, it is imperative to develop and implement appropriate strategies and technique for culturing stem cells and to confirm the genetic and epigenetic safety of these stem cells before employing them in clinical trials.

Dipeptide species regulate p38MAPK–Smad3 signalling to maintain chronic myelogenous leukaemia stem cells

PubMed Central

Naka, Kazuhito; Jomen, Yoshie; Ishihara, Kaori; Kim, Junil; Ishimoto, Takahiro; Bae, Eun-Jin; Mohney, Robert P.; Stirdivant, Steven M.; Oshima, Hiroko; Oshima, Masanobu; Kim, Dong-Wook; Nakauchi, Hiromitsu; Takihara, Yoshihiro; Kato, Yukio; Ooshima, Akira; Kim, Seong-Jin

2015-01-01

Understanding the specific survival of the rare chronic myelogenous leukaemia (CML) stem cell population could provide a target for therapeutics aimed at eradicating these cells. However, little is known about how survival signalling is regulated in CML stem cells. In this study, we survey global metabolic differences between murine normal haematopoietic stem cells (HSCs) and CML stem cells using metabolomics techniques. Strikingly, we show that CML stem cells accumulate significantly higher levels of certain dipeptide species than normal HSCs. Once internalized, these dipeptide species activate amino-acid signalling via a pathway involving p38MAPK and the stemness transcription factor Smad3, which promotes CML stem cell maintenance. Importantly, pharmacological inhibition of dipeptide uptake inhibits CML stem cell activity in vivo. Our results demonstrate that dipeptide species support CML stem cell maintenance by activating p38MAPK–Smad3 signalling in vivo, and thus point towards a potential therapeutic target for CML treatment. PMID:26289811

Engineering Stem Cells for Biomedical Applications.

PubMed

Yin, Perry T; Han, Edward; Lee, Ki-Bum

2016-01-07

Stem cells are characterized by a number of useful properties, including their ability to migrate, differentiate, and secrete a variety of therapeutic molecules such as immunomodulatory factors. As such, numerous pre-clinical and clinical studies have utilized stem cell-based therapies and demonstrated their tremendous potential for the treatment of various human diseases and disorders. Recently, efforts have focused on engineering stem cells in order to further enhance their innate abilities as well as to confer them with new functionalities, which can then be used in various biomedical applications. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle loading and delivery, and even small molecule drug delivery. The present Review gives an in-depth account of the current status of engineered stem cells, including potential cell sources, the most common methods used to engineer stem cells, and the utilization of engineered stem cells in various biomedical applications, with a particular focus on tissue regeneration, the treatment of immunodeficiency diseases, and cancer. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling TSC and LAM Using Patient Derived Induced Pluripotent Stem Cells

DTIC Science & Technology

2016-10-01

lentiviral knockdown, and CRISPR /Cas9 genome editing in embryonic stem cells (ESCs). We have characterized the iPSCs extensively and found that they display...induced pluripotent stem cells (iPSCs) embryonic stem cells (ESCs) reprogramming CRISPR /Cas9 genome editing neural stem cells (NSCs) neural crest... CRISPR /cas9 in two additional human pluripotent stem cell lines (WA07 (H7) – female cell line registry #0061; and a control male iPSC lines generated

Biochemistry of epidermal stem cells☆

PubMed Central

Eckert, Richard L.; Adhikary, Gautam; Balasubramanian, Sivaprakasam; Rorke, Ellen A.; Vemuri, Mohan C.; Boucher, Shayne E.; Bickenbach, Jackie R.; Kerr, Candace

2014-01-01

Background The epidermis is an important protective barrier that is essential for maintenance of life. Maintaining this barrier requires continuous cell proliferation and differentiation. Moreover, these processes must be balanced to produce a normal epidermis. The stem cells of the epidermis reside in specific locations in the basal epidermis, hair follicle and sebaceous glands and these cells are responsible for replenishment of this tissue. Scope of review A great deal of effort has gone into identifying protein epitopes that mark stem cells, in identifying stem cell niche locations, and in understanding how stem cell populations are related. We discuss these studies as they apply to understanding normal epidermal homeostasis and skin cancer. Major conclusions An assortment of stem cell markers have been identified that permit assignment of stem cells to specific regions of the epidermis, and progress has been made in understanding the role of these cells in normal epidermal homeostasis and in conditions of tissue stress. A key finding is the multiple stem cell populations exist in epidermis that give rise to different structures, and that multiple stem cell types may contribute to repair in damaged epidermis. General significance Understanding epidermal stem cell biology is likely to lead to important therapies for treating skin diseases and cancer, and will also contribute to our understanding of stem cells in other systems. This article is part of a Special Issue entitled Biochemistry of Stem Cells. PMID:22820019

Cryopreservation of Human Stem Cells for Clinical Application: A Review

PubMed Central

Hunt, Charles J.

2011-01-01

Summary Stem cells have been used in a clinical setting for many years. Haematopoietic stem cells have been used for the treatment of both haematological and non-haematological disease; while more recently mesenchymal stem cells derived from bone marrow have been the subject of both laboratory and early clinical studies. Whilst these cells show both multipotency and expansion potential, they nonetheless do not form stable cell lines in culture which is likely to limit the breadth of their application in the field of regenerative medicine. Human embryonic stem cells are pluripotent cells, capable of forming stable cell lines which retain the capacity to differentiate into cells from all three germ layers. This makes them of special significance in both regenerative medicine and toxicology. Induced pluripotent stem (iPS) cells may also provide a similar breadth of utility without some of the confounding ethical issues surrounding embryonic stem cells. An essential pre-requisite to the commercial and clinical application of stem cells are suitable cryopreservation protocols for long-term storage. Whilst effective methods for cryopreservation and storage have been developed for haematopoietic and mesenchymal stem cells, embryonic cells and iPS cells have proved more refractory. This paper reviews the current state of cryopreservation as it pertains to stem cells and in particular the embryonic and iPS cell. PMID:21566712

Cryopreservation of Human Stem Cells for Clinical Application: A Review.

PubMed

Hunt, Charles J

2011-01-01

SUMMARY: Stem cells have been used in a clinical setting for many years. Haematopoietic stem cells have been used for the treatment of both haematological and non-haematological disease; while more recently mesenchymal stem cells derived from bone marrow have been the subject of both laboratory and early clinical studies. Whilst these cells show both multipotency and expansion potential, they nonetheless do not form stable cell lines in culture which is likely to limit the breadth of their application in the field of regenerative medicine. Human embryonic stem cells are pluripotent cells, capable of forming stable cell lines which retain the capacity to differentiate into cells from all three germ layers. This makes them of special significance in both regenerative medicine and toxicology. Induced pluripotent stem (iPS) cells may also provide a similar breadth of utility without some of the confounding ethical issues surrounding embryonic stem cells. An essential pre-requisite to the commercial and clinical application of stem cells are suitable cryopreservation protocols for long-term storage. Whilst effective methods for cryopreservation and storage have been developed for haematopoietic and mesenchymal stem cells, embryonic cells and iPS cells have proved more refractory. This paper reviews the current state of cryopreservation as it pertains to stem cells and in particular the embryonic and iPS cell.

YAP/TAZ enhance mammalian embryonic neural stem cell characteristics in a Tead-dependent manner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Dasol; Byun, Sung-Hyun; Park, Soojeong

Mammalian brain development is regulated by multiple signaling pathways controlling cell proliferation, migration and differentiation. Here we show that YAP/TAZ enhance embryonic neural stem cell characteristics in a cell autonomous fashion using diverse experimental approaches. Introduction of retroviral vectors expressing YAP or TAZ into the mouse embryonic brain induced cell localization in the ventricular zone (VZ), which is the embryonic neural stem cell niche. This change in cell distribution in the cortical layer is due to the increased stemness of infected cells; YAP-expressing cells were colabeled with Sox2, a neural stem cell marker, and YAP/TAZ increased the frequency and sizemore » of neurospheres, indicating enhanced self-renewal- and proliferative ability of neural stem cells. These effects appear to be TEA domain family transcription factor (Tead)–dependent; a Tead binding-defective YAP mutant lost the ability to promote neural stem cell characteristics. Consistently, in utero gene transfer of a constitutively active form of Tead2 (Tead2-VP16) recapitulated all the features of YAP/TAZ overexpression, and dominant negative Tead2-EnR resulted in marked cell exit from the VZ toward outer cortical layers. Taken together, these results indicate that the Tead-dependent YAP/TAZ signaling pathway plays important roles in neural stem cell maintenance by enhancing stemness of neural stem cells during mammalian brain development. - Highlights: • Roles of YAP and Tead in vivo during mammalian brain development are clarified. • Expression of YAP promotes embryonic neural stem cell characteristics in vivo in a cell autonomous fashion. • Enhancement of neural stem cell characteristics by YAP depends on Tead. • Transcriptionally active form of Tead alone can recapitulate the effects of YAP. • Transcriptionally repressive form of Tead severely reduces stem cell characteristics.« less

Recent progress in stem cell differentiation directed by material and mechanical cues.

PubMed

Lin, Xunxun; Shi, Yuan; Cao, Yilin; Liu, Wei

2016-02-02

Stem cells play essential roles in tissue regeneration in vivo via specific lineage differentiation induced by environmental factors. In the past, biochemical signals were the focus of induced stem cell differentiation. As reported by Engler et al (2006 Cell 126 677-89), biophysical signal mediated stem cell differentiation could also serve as an important inducer. With the advancement of material science, it becomes a possible strategy to generate active biophysical signals for directing stem cell fate through specially designed material microstructures. In the past five years, significant progress has been made in this field, and these designed biophysical signals include material elasticity/rigidity, micropatterned structure, extracellular matrix (ECM) coated materials, material transmitted extracellular mechanical force etc. A large number of investigations involved material directed differentiation of mesenchymal stem cells, neural stem/progenitor cells, adipose derived stem cells, hematopoietic stem/progenitor cells, embryonic stem cells and other cells. Hydrogel based materials were commonly used to create varied mechanical properties via modifying the ratio of different components, crosslinking levels, matrix concentration and conjugation with other components. Among them, polyacrylamide (PAM) and polydimethylsiloxane (PDMS) hydrogels remained the major types of material. Specially designed micropatterning was not only able to create a unique topographical surface to control cell shape, alignment, cell-cell and cell-matrix contact for basic stem cell biology study, but also could be integrated with 3D bioprinting to generate micropattered 3D structure and thus to induce stem cell based tissue regeneration. ECM coating on a specific topographical structure was capable of inducing even more specific and potent stem cell differentiation along with soluble factors and mechanical force. The article overviews the progress of the past five years in this particular field.

Engineering Hydrogel Microenvironments to Recapitulate the Stem Cell Niche.

PubMed

Madl, Christopher M; Heilshorn, Sarah C

2018-06-04

Stem cells are a powerful resource for many applications including regenerative medicine, patient-specific disease modeling, and toxicology screening. However, eliciting the desired behavior from stem cells, such as expansion in a naïve state or differentiation into a particular mature lineage, remains challenging. Drawing inspiration from the native stem cell niche, hydrogel platforms have been developed to regulate stem cell fate by controlling microenvironmental parameters including matrix mechanics, degradability, cell-adhesive ligand presentation, local microstructure, and cell-cell interactions. We survey techniques for modulating hydrogel properties and review the effects of microenvironmental parameters on maintaining stemness and controlling differentiation for a variety of stem cell types. Looking forward, we envision future hydrogel designs spanning a spectrum of complexity, ranging from simple, fully defined materials for industrial expansion of stem cells to complex, biomimetic systems for organotypic cell culture models.

Incorporation of Biomaterials in Multicellular Aggregates Modulates Pluripotent Stem Cell Differentiation

PubMed Central

Bratt-Leal, Andrés M.; Carpenedo, Richard L.; Ungrin, Mark; Zandstra, Peter W.; McDevitt, Todd C.

2010-01-01

Biomaterials are increasingly being used to engineer the biochemical and biophysical properties of the extracellular stem cell microenvironment in order to tailor niche characteristics and direct cell phenotype. To date, stem cell-biomaterial interactions have largely been studied by introducing stem cells into artificial environments, such as 2D cell culture on biomaterial surfaces, encapsulation of cell suspensions within hydrogel materials, or cell seeding on 3D polymeric scaffolds. In this study, microparticles fabricated from different materials, such as agarose, PLGA and gelatin, were stably integrated, in a dose-dependent manner, within aggregates of pluripotent stem cells (PSCs) prior to differentiation as a means to directly examine stem cell-biomaterial interactions in 3D. Interestingly, the presence of the materials within the stem cell aggregates differentially modulated the gene and protein expression patterns of several differentiation markers without adversely affecting cell viability. Microparticle incorporation within 3D stem cell aggregates can control the spatial presentation of extracellular environmental cues (i.e. soluble factors, extracellular matrix and intercellular adhesion molecules) as a means to direct the differentiation of stem cells for tissue engineering and regenerative medicine applications. In addition, these results suggest that the physical presence of microparticles within stem cell aggregates does not compromise PSC differentiation, but in fact the choice of biomaterials can impact the propensity of stem cells to adopt particular differentiated cell phenotypes. PMID:20864164

Markers for the identification of tendon-derived stem cells in vitro and tendon stem cells in situ - update and future development.

PubMed

Lui, Pauline Po Yee

2015-06-02

The efficacy of tendon-derived stem cells (TDSCs) for the promotion of tendon and tendon-bone junction repair has been reported in animal studies. Modulation of the tendon stem cell niche in vivo has also been reported to influence tendon structure. There is a need to have specific and reliable markers that can define TDSCs in vitro and tendon stem cells in situ for several reasons: to understand the basic biology of TDSCs and their subpopulations in vitro; to understand the identity, niches and functions of tendon/progenitor stem cells in vivo; to meet the governmental regulatory requirements for quality of TDSCs when translating the exciting preclinical findings into clinical trial/practice; and to develop new treatment strategies for mobilizing endogenous stem/progenitor cells in tendon. TDSCs were reported to express the common mesenchymal stem cell (MSC) markers and some embryonic stem cell (ESC) markers, and there were attempts to use these markers to label tendon stem cells in situ. Are these stem cell markers useful for the identification of TDSCs in vitro and tracking of tendon stem cells in situ? This review aims to discuss the values of the panel of MSC, ESC and tendon-related markers for the identification of TDSCs in vitro. Important factors influencing marker expression by TDSCs are discussed. The usefulness and limitations of the panel of MSC, ESC and tendon-related markers for tracking stem cells in tendon, especially tendon stem cells, in situ are then reviewed. Future research directions are proposed.

Haematopoietic stem and progenitor cells from human pluripotent stem cells

PubMed Central

Sugimura, Ryohichi; Jha, Deepak Kumar; Han, Areum; Soria-Valles, Clara; da Rocha, Edroaldo Lummertz; Lu, Yi-Fen; Goettel, Jeremy A.; Serrao, Erik; Rowe, R. Grant; Malleshaiah, Mohan; Wong, Irene; Sousa, Patricia; Zhu, Ted N.; Ditadi, Andrea; Keller, Gordon; Engelman, Alan N.; Snapper, Scott B.; Doulatov, Sergei; Daley, George Q.

2018-01-01

A variety of tissue lineages can be differentiated from pluripotent stem cells by mimicking embryonic development through stepwise exposure to morphogens, or by conversion of one differentiated cell type into another by enforced expression of master transcription factors. Here, to yield functional human haematopoietic stem cells, we perform morphogen-directed differentiation of human pluripotent stem cells into haemogenic endothelium followed by screening of 26 candidate haematopoietic stem-cell-specifying transcription factors for their capacity to promote multi-lineage haematopoietic engraftment in mouse hosts. We recover seven transcription factors (ERG, HOXA5, HOXA9, HOXA10, LCOR, RUNX1 and SPI1) that are sufficient to convert haemogenic endothelium into haematopoietic stem and progenitor cells that engraft myeloid, B and T cells in primary and secondary mouse recipients. Our combined approach of morphogen-driven differentiation and transcription-factor-mediated cell fate conversion produces haematopoietic stem and progenitor cells from pluripotent stem cells and holds promise for modelling haematopoietic disease in humanized mice and for therapeutic strategies in genetic blood disorders. PMID:28514439

Stem Cells in the Trabecular Meshwork for Regulating Intraocular Pressure.

PubMed

Yun, Hongmin; Zhou, Yi; Wills, Andrew; Du, Yiqin

2016-06-01

Intraocular pressure (IOP) is still the main treatment target for glaucoma. Outflow resistance mainly exists at the trabecular meshwork (TM) outflow pathway, which is responsible for IOP regulation. Changes of TM cellularity and TM extracellular matrix turnover may play important roles in IOP regulation. In this article, we review basic anatomy and physiology of the outflow pathway and TM stem cell characteristics regarding the location, isolation, identification and function. TM stem cells are localized at the insert region of the TM and are label-retaining in vivo. They can be isolated by side-population cell sorting, cloning culture, or sphere culture. TM stem cells are multipotent with the ability to home to the TM region and differentiate into TM cells in vivo. Other stem cell types, such as adipose-derived stem cells, mesenchymal stem cells and induced pluripotent stem cells have been discovered for TM cell differentiation and TM regeneration. We also review glaucomatous animal models, which are suitable to study stem cell-based therapies for TM regeneration.

Stem Cells in the Trabecular Meshwork for Regulating Intraocular Pressure

PubMed Central

Yun, Hongmin; Zhou, Yi; Wills, Andrew

2016-01-01

Abstract Intraocular pressure (IOP) is still the main treatment target for glaucoma. Outflow resistance mainly exists at the trabecular meshwork (TM) outflow pathway, which is responsible for IOP regulation. Changes of TM cellularity and TM extracellular matrix turnover may play important roles in IOP regulation. In this article, we review basic anatomy and physiology of the outflow pathway and TM stem cell characteristics regarding the location, isolation, identification and function. TM stem cells are localized at the insert region of the TM and are label-retaining in vivo. They can be isolated by side-population cell sorting, cloning culture, or sphere culture. TM stem cells are multipotent with the ability to home to the TM region and differentiate into TM cells in vivo. Other stem cell types, such as adipose-derived stem cells, mesenchymal stem cells and induced pluripotent stem cells have been discovered for TM cell differentiation and TM regeneration. We also review glaucomatous animal models, which are suitable to study stem cell-based therapies for TM regeneration. PMID:27183473

Combined intravitreal bevacizumab and photodynamic therapy with vertiporfin for management of choroidal neovascularization secondary to age-related macular degeneration

PubMed Central

Kabeel, Mamdouh M; El-Batarny, Ashraf M; Tameesh, Mohamed K; Abou El Enein, Moustafa A

2008-01-01

Purpose To test the results for patients treated with combined photodynamic therapy (PDT) with vertiporfin (Visudyne, Novartis AG) and intravitreal bevacizumab for choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD). Patients and methods This is a prospective study including 18 eyes with subfoveal or juxtafoveal CNV secondary to AMD. Patients were treated with intravitreal bevacizumab 2.5 mg in the morning then PDT with vertiporfin in the evening of the same day. All patients were followed up for 6 months. The main outcome measures were stabilization (no change) or improvement of best corrected visual acuity (BCVA) with no leakage in fluorescein angiography (FLA) and reduction of central retinal thickness, and retreatment rate. Results At the end of 6 months follow up, all cases had either stabilization or improved BCVA. Fifteen eyes (80%) showed improved BCVA. The overall mean improvement in BCVA (n = 18) was 2.17 lines. Fifteen eyes (80%) required single combined treatment. Only 3 eyes (20%) required retreatment with the same protocol. No systemic or ocular complications were reported. Conclusion Combined intravitreal bevacizumab and PDT as a treatment of CNV secondary to AMD either for predominantly classic or occult subtypes has a positive therapeutic effect with stabilization or improvement of final BCVA and also might reduce the need for retreatment compared with literature retreatment rates of either modality alone. Summary Eighteen patients receiving combined therapy with PDT and intravitreal bevacizumab for CNV secondary to AMD, showed not only significant visual improvement but also reduction in the frequency of retreatment when compared to the results of monotherapy with each modality. PMID:19668400

Profiling safety of intravitreal injections for retinoblastoma using an anti-reflux procedure and sterilisation of the needle track.

PubMed

Munier, Francis L; Soliman, Sameh; Moulin, Alexandre P; Gaillard, Marie-Claire; Balmer, Aubin; Beck-Popovic, Maja

2012-08-01

The preservation of globe integrity has always been a major concern during the treatment of retinoblastoma for fear of extraocular or metastatic spread. Intravitreal chemotherapy has been attempted as a desperate salvage therapy only for eyes with refractory retinoblastoma. Published data on the safety and efficacy of this route are, however, limited. A modified technique of intravitreal injection in eyes with retinoblastoma is described. All children with retinoblastoma who received one or more intravitreal injections using this technique were retrospectively reviewed concerning ocular complications of the injection procedure as well as clinical or histopathological evidence of tumour spread. 30 eyes of 30 children with retinoblastoma received a total of 135 intravitreal injections, with a median follw-up duration of 13.5 months. No extraocular spread was seen on clinical follow-up in any patients and there was no tumour contamination of the retrieved entry sites histopathologically analysed among the five enucleated eyes. No significant ocular side effects were observed except transient localised vitreous haemorrhage (3/135). This technique is potentially safe and effective at a low cost and may play a promising role, especially in the treatment of recurrent and/or resistant vitreous disease in retinoblastoma, as an alternative to enucleation and/or external beam radiotherapy. However, this treatment should not replace the primary standard of care of retinoblastoma and should not be considered in group E eyes. Its application should be approved by an ophthalmological-oncological team and it should be performed by an experienced eye surgeon in a tertiary referral centre after careful selection of a tumour-free injection site.

Intravitreous injection of bevacizumab, tissue plasminogen activator, and gas in the treatment of submacular hemorrhage in age-related macular degeneration.

PubMed

Guthoff, Rainer; Guthoff, Tanja; Meigen, Thomas; Goebel, Winfried

2011-01-01

To investigate the benefit of adding bevacizumab to intravitreal recombinant tissue plasminogen activator (rTPA) and gas as initial therapy in subretinal hemorrhage and choroidal neovascularization because of age-related macular degeneration. Thirty-eight consecutive patients with recent (1-31 days) subretinal hemorrhage who were treated with intravitreal rTPA and gas (26 patients) or with intravitreal bevacizumab, rTPA, and gas (12 patients) were included in this retrospective analysis. In all patients, a standardized antivascular endothelial growth factor therapy was followed. Testing of best-corrected visual acuity, biomicroscopy, and fundus examination were performed at 4 weeks and 7 months. The mean pretreatment best-corrected visual acuity in the rTPA/gas group was 0.08 ± 0.09 and 0.12 ± 0.13 in the bevacizumab/rTPA/gas group. After 4 weeks, it was significantly higher in the bevacizumab/rTPA/gas group (0.25 ± 0.26) than in the rTPA/gas (0.08 ± 0.1) group (P < 0.05). Also, after 7 months, best-corrected visual acuity was significantly higher in the bevacizumab/rTPA/gas group (0.07 ± 0.07 vs. 0.24 ± 0.35; P < 0.05). Reading vision could be restored in 0% (rTPA/gas) versus 50% (bevacizumab/rTPA/gas). Stabilization (0 ± 2 lines) or improvement of best-corrected visual acuity was obtained in 62% (rTPA/gas) versus 84% (bevacizumab/rTPA/gas). From our retrospective pilot study, there is a strong indication that the addition of intravitreal bevacizumab is safe and superior to the displacement of submacular hemorrhages alone with rTPA and gas.

Efficacy of Intravitreal Bevacizumab for Stage 3+ Retinopathy of Prematurity

PubMed Central

Mintz-Hittner, Helen A.; Kennedy, Kathleen A.; Chuang, Alice Z.

2011-01-01

BACKGROUND Retinopathy of prematurity is a leading cause of childhood blindness worldwide. Peripheral retinal ablation with conventional (confluent) laser therapy is destructive, causes complications, and does not prevent all vision loss, especially in cases of retinopathy of prematurity affecting zone I of the eye. Case series in which patients were treated with vascular endothelial growth factor inhibitors suggest that these agents may be useful in treating retinopathy of prematurity. METHODS We conducted a prospective, controlled, randomized, stratified, multicenter trial to assess intravitreal bevacizumab monotherapy for zone I or zone II posterior stage 3+ (i.e., stage 3 with plus disease) retinopathy of prematurity. Infants were randomly assigned to receive intravitreal bevacizumab (0.625 mg in 0.025 ml of solution) or conventional laser therapy, bilaterally. The primary ocular outcome was recurrence of retinopathy of prematurity in one or both eyes requiring retreatment before 54 weeks’ postmenstrual age. RESULTS We enrolled 150 infants (total sample of 300 eyes); 143 infants survived to 54 weeks’ postmenstrual age, and the 7 infants who died were not included in the primary-outcome analyses. Retinopathy of prematurity recurred in 4 infants in the bevacizumab group (6 of 140 eyes [4%]) and 19 infants in the laser-therapy group (32 of 146 eyes [22%], P = 0.002). A significant treatment effect was found for zone I retinopathy of prematurity (P = 0.003) but not for zone II disease (P = 0.27). CONCLUSIONS Intravitreal bevacizumab monotherapy, as compared with conventional laser therapy, in infants with stage 3+ retinopathy of prematurity showed a significant benefit for zone I but not zone II disease. Development of peripheral retinal vessels continued after treatment with intravitreal bevacizumab, but conventional laser therapy led to permanent destruction of the peripheral retina. This trial was too small to assess safety. PMID:21323540

POOLED ESTIMATES OF INCIDENCE OF ENDOPHTHALMITIS AFTER INTRAVITREAL INJECTION OF ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR AGENTS WITH AND WITHOUT TOPICAL ANTIBIOTIC PROPHYLAXIS.

PubMed

Reibaldi, Michele; Pulvirenti, Alfredo; Avitabile, Teresio; Bonfiglio, Vincenza; Russo, Andrea; Mariotti, Cesare; Bucolo, Claudio; Mastropasqua, Rodolfo; Parisi, Guglielmo; Longo, Antonio

2018-01-01

To assess the effect of topical antibiotic prophylaxis on postoperative endophthalmitis after intravitreal injection of anti-vascular endothelial growth factor agents. A systematic literature search was performed from inception to March 2016 using PubMed, Medline, Web of Science, Embase, and the Cochrane Library, to identify articles that reported cases of endophthalmitis after intravitreal injection of anti-vascular endothelial growth factor agents. We used a pooled analysis to estimate the incidence of cases of endophthalmitis who developed after injections performed with and without topical antibiotic prophylaxis. We used regression analysis to explore the effects of study characteristics on heterogeneity. From our search of electronic databases, we identified and screened 4,561 unique records. We judged 60 articles to have reported findings for cohorts of patients who met our inclusion criteria, (12 arms of randomized clinical trials, 11 prospective cohort studies, and 37 retrospective cohort studies), which included 244 cases of endophthalmitis and 639,391 intravitreal injections of anti-vascular endothelial growth factor agents. The final pooled estimate endophthalmitis proportions were 9/10,000 (95% confidence interval, 7/10,000-12/10,000) in the antibiotic-treated group and 3/10,000 (95% confidence interval, 2/10,000-5/10,000) in the untreated group. The estimated incidence of endophthalmitis with topical antibiotic prophylaxis was approximated three times the incidence without prophylaxis. Random effects regression showed that none of the study characteristics significantly affected the effect size in either group. Topical antibiotic after intravitreal injection of anti-vascular endothelial growth factor agents is associated with a higher risk of endophthalmitis.

Minimizing the endophthalmitis rate following intravitreal injections using 0.25% povidone-iodine irrigation and surgical mask.

PubMed

Shimada, Hiroyuki; Hattori, Takayuki; Mori, Ryusaburo; Nakashizuka, Hiroyuki; Fujita, Kyoko; Yuzawa, Mitsuko

2013-08-01

To examine the efficacy of complying with an infection control manual for intravitreal injection of anti-vascular endothelial growth factor (VEGF) preparations in reducing the rate of endophthalmitis. We retrospectively reviewed intravitreal anti-VEGF injections conducted by vitreoretinal specialists at the outpatient injection room of a single university hospital between July 2009 and July 2012. The injections were conducted following an infection control manual established by our department. Doctors and nurses wore surgical masks, and disinfected the patient's eyelid skin with 10% povidone-iodine and then the conjunctiva with 0.25% povidone-iodine. After putting a drape on the patient's face, a lid speculum was placed. The conjunctival surface was again washed with 5 ml of 0.25% povidone-iodine. After waiting at least 30 seconds, intravitreal injection was performed through povidone-iodine. Following injection, the injection site was again washed with 5 ml of 0.25% povidone-iodine. Patients were treated with topical levofloxacin 4 times a day for 3 days before and after the injection. A total of 15,144 injections comprising 548 injections of pegaptanib sodium, 846 injections of bevacizumab, and 13,750 injections of ranibizumab were performed. During this period, no case of suspected or proven infectious endophthalmitis occurred. The endophthalmitis rate was 0 per 15,144 injections, (95% confidence interval, 0.0-0.0%). The results suggest that endophthalmitis can be reduced to a minimum by preventing normal flora of the conjunctiva and bacteria in the oral cavity from entering the vitreous. For this purpose, an infection control manual that requires nurses and doctors to wear surgical mask and drape the patient's face, irrigate the conjunctiva with 0.25% povidone-iodine and wait at least 30 seconds before performing intravitreal injection is useful.

Ocular side effects following intravitreal injection therapy for retinoblastoma: a systematic review.

PubMed

Smith, Stephen J; Smith, Brian D; Mohney, Brian G

2014-03-01

To describe the ocular side effects in patients receiving intravitreal injection therapy (IViT) for retinoblastoma. PubMed (1946-present), Scopus (all years), Science Citation Index (1900-present) and Conference Proceedings Citation Index-Science (1990-present) electronic databases were searched to identify all published reports of therapeutic intravitreal injections for retinoblastoma in humans. Ten studies with original IViT ocular side effect data were included in this systematic review. In these combined reports, a total of 1287 intravitreal injections were given to 306 eyes of 295 patients, with a mean follow-up of 74.1 months. Two hundred sixty-one (88.5%) patients received comparatively standard melphalan IViT doses (8-30 mcg). Ocular side effects occurred in 38 patients (17 significant, 21 minor). The proportion of patients experiencing potentially significant ocular side effects following standard melphalan IViT regimens was 0.031 (8/261; 95% CI 0.013 to 0.06). The side effects of these eight included iris atrophy in three, two each with chorioretinal atrophy and vitreous haemorrhage and one with retinal detachment. Of the other nine patients with significant complications, five experienced sight-threatening complications following dramatic dose escalations (four with melphalan, one with thiotepa), three experienced complications that are commonly associated with concurrent therapies given to these patients and one had a retinal detachment. Of the 61 patients receiving IViT via safety-enhancing injection techniques, all six significant side effects were either attributed to the therapeutic dose or confounded by concurrent treatments. Significant ocular complications following IViT for retinoblastoma are uncommon, and this risk may be reduced further by the use of careful injection technique and standard dosing regimens. Care must be taken in the dosing of intravitreal treatments to avoid potentially irreversible vision loss.

Intravitreal bevacizumab (Avastin) treatment of diffuse diabetic macular edema in an Indian population

PubMed Central

Sinha, Subijay

2007-01-01

Background: To report the anatomic and visual acuity response after intravitreal bevacizumab (Avastin) in patients with diffuse diabetic macular edema. Design: Prospective, interventional case series study. Materials and Methods: This study included 20 eyes of metabolically stable diabetes mellitus with diffuse diabetic macular edema with a mean age of 59 years who were treated with two intravitreal injections of bevacizumab 1.25 mg in 0.05 ml six weeks apart. Main outcome measures were 1) early treatment diabetic retinopathy study visual acuity, 2) central macular thickness by optical coherence tomography imaging. Each was evaluated at baseline and follow-up visits. Results: All the eyes had received some form of laser photocoagulation before (not less than six months ago), but all of these patients had persistent diffuse macular edema with no improvement in visual acuity. All the patients received two injections of bevacizumab at an interval of six weeks per eye. No adverse events were observed, including endophthalmitis, inflammation and increased intraocular pressure or thromboembolic events in any patient. The mean baseline acuity was 20/494 (log Mar=1.338±0.455) and the mean acuity at three months following the second intravitreal injection was 20/295 (log Mar=1.094±0.254), a difference that was highly significant ( P =0.008). The mean central macular thickness at baseline was 492 µm which decreased to 369 µm ( P =0.001) at the end of six months. Conclusions: Initial treatment results of patients with diffuse diabetic macular edema not responding to previous photocoagulation did not reveal any short-term safety concerns. Intravitreal bevacizumab resulted in a significant decrease in macular thickness and improvement in visual acuity at three months but the effect was somewhat blunted, though still statistically significant at the end of six months. PMID:17951903

The Effect of Different Dosing Schedules of Intravitreal Sirolimus, a Mammalian Target of Rapamycin (mTOR) Inhibitor, in the Treatment of Non-Infectious Uveitis (An American Ophthalmological Society Thesis).

PubMed

Nguyen, Quan Dong; Sadiq, Mohammad Ali; Soliman, Mohamed Kamel; Agarwal, Aniruddha; Do, Diana V; Sepah, Yasir J

2016-08-01

To determine if two different doses of intravitreal sirolimus, an mTOR inhibitor, can decrease inflammation and is safe in eyes with non-infectious posterior, intermediate, or panuveitis in the Sirolimus as a Therapeutic Approach UVEitis: Protocol-2 (SAVE-2) Study. SAVE-2 is a prospective randomized, phase II, open-label interventional clinical trial conducted at 4 clinical centers in the United States. Eligible subjects were randomized into one of two treatments. Group 1 received 440µg of intravitreal sirolimus in study eyes on days 0, 30, 60, 90, 120, and 150; group 2 received 880µg of intravitreal sirolimus on days 0, 60, and 120. Fellow eyes were also eligible to receive sirolimus (of opposite dose to that of study eye). Primary endpoint of the study was at month 6 (M6). 24 subjects have been randomized in SAVE-2 and are included in the analysis. Vitreous haze decreased by ≥2 steps in 63.6% and 50% of patients in groups 1 and 2, respectively at M6 (p=0.695). Mean change in best-corrected visual acuity for subjects was +3.66 and -2.91 ETDRS letters in group 1 and 2, respectively. Among subjects with macular edema at baseline (n=13), the mean change in foveal thickness was -89.42µm in group 1 and +81.5µm in group 2 at M6. Both low and high doses of intravitreal sirolimus were found to decrease vitreous haze in eyes with non-infectious uveitis. Low dose (440µg) sirolimus administered monthly may be more efficacious in reducing uveitic macular edema than high dose (880µg) administered every 2 months.

The Effect of Different Dosing Schedules of Intravitreal Sirolimus, a Mammalian Target of Rapamycin (mTOR) Inhibitor, in the Treatment of Non-Infectious Uveitis (An American Ophthalmological Society Thesis)

PubMed Central

Nguyen, Quan Dong; Sadiq, Mohammad Ali; Soliman, Mohamed Kamel; Agarwal, Aniruddha; Do, Diana V.; Sepah, Yasir J.

2016-01-01

Purpose: To determine if two different doses of intravitreal sirolimus, an mTOR inhibitor, can decrease inflammation and is safe in eyes with non-infectious posterior, intermediate, or panuveitis in the Sirolimus as a Therapeutic Approach UVEitis: Protocol-2 (SAVE-2) Study. Methods: SAVE-2 is a prospective randomized, phase II, open-label interventional clinical trial conducted at 4 clinical centers in the United States. Eligible subjects were randomized into one of two treatments. Group 1 received 440µg of intravitreal sirolimus in study eyes on days 0, 30, 60, 90, 120, and 150; group 2 received 880µg of intravitreal sirolimus on days 0, 60, and 120. Fellow eyes were also eligible to receive sirolimus (of opposite dose to that of study eye). Primary endpoint of the study was at month 6 (M6). Results: 24 subjects have been randomized in SAVE-2 and are included in the analysis. Vitreous haze decreased by ≥2 steps in 63.6% and 50% of patients in groups 1 and 2, respectively at M6 (p=0.695). Mean change in best-corrected visual acuity for subjects was +3.66 and −2.91 ETDRS letters in group 1 and 2, respectively. Among subjects with macular edema at baseline (n=13), the mean change in foveal thickness was −89.42µm in group 1 and +81.5µm in group 2 at M6. Conclusions: Both low and high doses of intravitreal sirolimus were found to decrease vitreous haze in eyes with non-infectious uveitis. Low dose (440µg) sirolimus administered monthly may be more efficacious in reducing uveitic macular edema than high dose (880µg) administered every 2 months. PMID:27630374

Intraocular methotrexate in the treatment of uveitis and uveitic cystoid macular edema.

PubMed

Taylor, Simon R J; Habot-Wilner, Zohar; Pacheco, Patricio; Lightman, Sue L

2009-04-01

A pilot study to evaluate the use of intravitreal methotrexate (MTX) for the treatment of uveitis and uveitic cystoid macular edema (CME). Prospective, consecutive, interventional case series. Fifteen eyes of 15 patients with a unilateral exacerbation of noninfectious intermediate, posterior uveitis, or panuveitis and/or CME such that visual acuity (VA) was 20/40 or worse, together with a history of increased intraocular pressure (IOP) in response to corticosteroid administration. Intravitreal injection of 400 microg in 0.1 ml MTX. The primary outcome measure was VA (using the Early Treatment Diabetic Retinopathy Study chart). Other outcome measures included ocular inflammation scores, time to relapse, levels of systemic corticosteroid and immunosuppressive therapy, and ocular coherence tomography. Potential complications of intravitreal MTX injection, including cataract progression, vitreous hemorrhage, retinal detachment, and corneal epitheliopathy, were assessed. VA improved at all time points and was statistically significant at the 3- and 6-month follow-up examinations. The mean visual improvement was 4 lines at 3 months and 4.5 lines at 6 months, with no statistical difference between the best VA obtained after MTX injection and after previous corticosteroid treatment, including intravitreal triamcinolone acetate injection. Five patients relapsed after a median of 4 months; a similar improvement was seen after re-injection. Ocular inflammation scores improved at all time points, and systemic immunosuppressive medication was reduced in 3 of 7 patients taking this at the start of the trial. In patients with uveitis and uveitic CME, intravitreal MTX can improve VA and reduce CME and, in some patients, allows the reduction of immunosuppressive therapy. Relapse occurs at a median of 4 months in some patients, but reinjection has similar efficacy.

Intraocular methotrexate can induce extended remission in some patients in noninfectious uveitis.

PubMed

Taylor, Simon R J; Banker, Alay; Schlaen, Ariel; Couto, Cristobal; Matthe, Egbert; Joshi, Lavnish; Menezo, Victor; Nguyen, Ethan; Tomkins-Netzer, Oren; Bar, Asaf; Morarji, Jiten; McCluskey, Peter; Lightman, Sue

2013-01-01

To assess the outcomes of the intravitreal administration of methotrexate in uveitis. Multicenter, retrospective interventional case series of patients with noninfectious uveitis. Thirty-eight eyes of 30 patients were enrolled, including a total of 54 intravitreal injections of methotrexate at a dose of 400 µg in 0.1 mL. The primary outcome measure was visual acuity. Secondary outcome measures included control of intraocular inflammation and cystoid macular edema, time to relapse, development of adverse events, and levels of systemic corticosteroid and immunosuppressive therapy. Methotrexate proved effective in controlling intraocular inflammation and improving vision in 30 of 38 eyes (79%). The side effect profile was good, with no reported serious ocular adverse events and only one patient having an intraocular pressure of >21 mmHg. Of the 30 eyes that responded to treatment, 8 relapsed, but 22 (73%) entered an extended period of remission, with the Kaplan-Meier estimate of median time to relapse for the whole group being 17 months. The eight eyes that relapsed were reinjected and all responded to treatment. One eye relapsed at 3 months, but 7 eyes again entered extended remission. Of the 14 patients on systemic therapy at the start of the study, 8 (57%) were able to significantly reduce this following intravitreal methotrexate injection. In patients with uveitis and uveitic cystoid macular edema, intravitreal MTX can effectively improve visual acuity and reduce cystoid macular edema and, in some patients, allows the reduction of immunosuppressive therapy. Some patients relapse at 3 to 4 months, but a large proportion (73%) enter an extended period of remission of up to 18 months. This larger study extends the results obtained from previous smaller studies suggesting the viability of intravitreal methotrexate as a treatment option in uveitis.

New perspectives in human stem cell therapeutic research.

PubMed

Trounson, Alan

2009-06-11

Human stem cells are in evaluation in clinical stem cell trials, primarily as autologous bone marrow studies, autologous and allogenic mesenchymal stem cell trials, and some allogenic neural stem cell transplantation projects. Safety and efficacy are being addressed for a number of disease state applications. There is considerable data supporting safety of bone marrow and mesenchymal stem cell transplants but the efficacy data are variable and of mixed benefit. Mechanisms of action of many of these cells are unknown and this raises the concern of unpredictable results in the future. Nevertheless there is considerable optimism that immune suppression and anti-inflammatory properties of mesenchymal stem cells will be of benefit for many conditions such as graft versus host disease, solid organ transplants and pulmonary fibrosis. Where bone marrow and mesenchymal stem cells are being studied for heart disease, stroke and other neurodegenerative disorders, again progress is mixed and mostly without significant benefit. However, correction of multiple sclerosis, at least in the short term is encouraging. Clinical trials on the use of embryonic stem cell derivatives for spinal injury and macular degeneration are beginning and a raft of other clinical trials can be expected soon, for example, the use of neural stem cells for killing inoperable glioma and embryonic stem cells for regenerating beta islet cells for diabetes. The change in attitude to embryonic stem cell research with the incoming Obama administration heralds a new co-operative environment for study and evaluation of stem cell therapies. The Californian stem cell initiative (California Institute for Regenerative Medicine) has engendered global collaboration for this new medicine that will now also be supported by the US Federal Government. The active participation of governments, academia, biotechnology, pharmaceutical companies, and private investment is a powerful consortium for advances in health.

Invincible, but not invisible: imaging approaches toward in vivo detection of cancer stem cells.

PubMed

Hart, Lori S; El-Deiry, Wafik S

2008-06-10

With evidence emerging in support of a cancer stem-cell model of carcinogenesis, it is of paramount importance to identify and image these elusive cells in their natural environment. The cancer stem-cell hypothesis has the potential to explain unresolved questions of tumorigenesis, tumor heterogeneity, chemotherapeutic and radiation resistance, and even the metastatic phenotype. Intravital imaging of cancer stem cells could be of great value for determining prognosis, as well as monitoring therapeutic efficacy and influencing therapeutic protocols. Cancer stem cells represent a rare population of cells, as low as 0.1% of cells within a human tumor, and the phenotype of isolated cancer stem cells is easily altered when placed under in vitro conditions. This represents a challenge in studying cancer stem cells without manipulation or extraction from their natural environment. Advanced imaging techniques allow for the in vivo observation of physiological events at cellular resolution. Cancer stem-cell studies must take advantage of such technology to promote a better understanding of the cancer stem-cell model in relation to tumor growth and metastasis, as well as to potentially improve on the principles by which cancers are treated. This review examines the opportunities for in vivo imaging of putative cancer stem cells with regard to currently accepted cancer stem-cell characteristics and advanced imaging technologies.

Neural stem cell-based treatment for neurodegenerative diseases.

PubMed

Kim, Seung U; Lee, Hong J; Kim, Yun B

2013-10-01

Human neurodegenerative diseases such as Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD) are caused by a loss of neurons and glia in the brain or spinal cord. Neurons and glial cells have successfully been generated from stem cells such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs) and neural stem cells (NSCs), and stem cell-based cell therapies for neurodegenerative diseases have been developed. A recent advance in generation of a new class of pluripotent stem cells, induced pluripotent stem cells (iPSCs), derived from patients' own skin fibroblasts, opens doors for a totally new field of personalized medicine. Transplantation of NSCs, neurons or glia generated from stem cells in animal models of neurodegenerative diseases, including PD, HD, ALS and AD, demonstrates clinical improvement and also life extension of these animals. Additional therapeutic benefits in these animals can be provided by stem cell-mediated gene transfer of therapeutic genes such as neurotrophic factors and enzymes. Although further research is still needed, cell and gene therapy based on stem cells, particularly using neurons and glia derived from iPSCs, ESCs or NSCs, will become a routine treatment for patients suffering from neurodegenerative diseases and also stroke and spinal cord injury. © 2013 Japanese Society of Neuropathology.

Constitutive Proteasomal Degradation of TWIST-1 in Epithelial Ovarian Cancer Stem Cells Impacts Differentiation and Metastatic Potential

PubMed Central

Yin, Gang; Alvero, Ayesha B.; Craveiro, Vinicius; Holmberg, Jennie C.; Fu, Han-Hsuan; Montagna, Michele K.; Yang, Yang; Chefetz-Menaker, Ilana; Nuti, Sudhakar; Rossi, Michael; Silasi, Dan-Arin; Rutherford, Thomas; Mor, Gil

2013-01-01

Epithelial-mesenchymal transition (EMT) is a critical process for embryogenesis but is abnormally activated during cancer metastasis and recurrence. This process enables epithelial cancer cells to acquire mobility and traits associated with stemness. It is unknown whether epithelial stem cells or epithelial cancer stem cells are able to undergo EMT, and what molecular mechanism regulates this process in these specific cell types. We found that Epithelial Ovarian Cancer Stem cells (EOC stem cells) are the source of metastatic progenitor cells through a differentiation process involving EMT and Mesenchymal-Epithelial Transition (MET). We demonstrate both in vivo and in vitro the differentiation of EOC stem cells into mesenchymal spheroid-forming cells (MSFCs) and their capacity to initiate an active carcinomatosis. Furthermore, we demonstrate that human EOC stem cells injected i.p in mice are able to form ovarian tumors, suggesting that the EOC stem cells have the ability to “home” to the ovaries and establish tumors. Most interestingly, we found that TWIST1 is constitutively degraded in EOC stem cells, and that the acquisition of TWIST1 requires additional signals that will trigger the differentiation process. These findings are relevant for understanding the differentiation and metastasis process in EOC stem cells. PMID:22349827

Hepatic differentiation of pluripotent stem cells.

PubMed

Loya, Komal; Eggenschwiler, Reto; Ko, Kinarm; Sgodda, Malte; André, Francoise; Bleidissel, Martina; Schöler, Hans R; Cantz, Tobias

2009-10-01

In regenerative medicine pluripotent stem cells are considered to be a valuable self-renewing source for therapeutic cell transplantations, given that a functional organ-specific phenotype can be acquired by in vitro differentiation protocols. Furthermore, derivatives of pluripotent stem cells that mimic fetal progenitor stages could serve as an important tool to analyze organ development with in vitro approaches. Because of ethical issues regarding the generation of human embryonic stem (ES) cells, other sources for pluripotent stem cells are intensively studied. Like in less developed vertebrates, pluripotent stem cells can be generated from the female germline even in mammals, via parthenogenetic activation of oocytes. Recently, testis-derived pluripotent stem cells were derived from the male germline. Therefore, we compared two different hepatic differentiation approaches and analyzed the generation of definitive endoderm progenitor cells and their further maturation into a hepatic phenotype using murine parthenogenetic ES cells, germline-derived pluripotent stem cells, and ES cells. Applying quantitative RT-PCR, both germline-derived pluripotent cell lines show similar differentiation capabilities as normal murine ES cells and can be considered an alternative source for pluripotent stem cells in regenerative medicine.

An overview on ethical considerations in stem cell research in Iran and ethical recommendations: A review.

PubMed

Farajkhoda, Tahmineh

2017-02-01

Conducting research on the stem cell lines might bring some worthy good to public. Human Stem Cells (hSCs) research has provided opportunities for scientific progresses and new therapies, but some complex ethical matters should be noticed to ensure that stem cell research is carried out in an ethically appropriate manner. The aim of this review article is to discuss the importance of stem cell research, code of ethics for stem cell research in Iran and ethical recommendation. Generation of stem cells for research from human embryo or adult stem cells, saving, maintenance and using of them are the main ethical, legal and jurisprudence concerns in Iran. Concerns regarding human reproduction or human cloning, breach of human dignity, genetic manipulation and probability of tumorogenisity are observed in adult/somatic stem cells. Destruction of embryo to generate stem cell is an important matter in Iran. In this regards, obtaining stem cell from donated frozen embryos through infertility treatment that would be discarded is an acceptable solution in Iran for generation of embryo for research. Ethical, legal, and jurisprudence strategies for using adult/somatic stem cells are determination of ownership of stem cells, trade prohibition of human body, supervision on bio banks and information of Oversight Committee on Stem Cell Research. Recommendations to handle ethical issues for conducting stem cell research are well-designed studies, compliance codes of ethics in biomedical research (specifically codes of ethics on stem cell research, codes of ethics on clinical trials studies and codes of ethics on animals studies), appropriate collaboration with ethics committees and respecting of rights of participants (including both of human and animal rights) in research. In addition, there is a necessity for extending global networks of bioethics for strengthening communications within organizations at both the regional and international level, strengthening legislation systems, designing and establishing convenient collaborative educational courses at different levels.

An overview on ethical considerations in stem cell research in Iran and ethical recommendations: A review

PubMed Central

Farajkhoda, Tahmineh

2017-01-01

Conducting research on the stem cell lines might bring some worthy good to public. Human Stem Cells (hSCs) research has provided opportunities for scientific progresses and new therapies, but some complex ethical matters should be noticed to ensure that stem cell research is carried out in an ethically appropriate manner. The aim of this review article is to discuss the importance of stem cell research, code of ethics for stem cell research in Iran and ethical recommendation. Generation of stem cells for research from human embryo or adult stem cells, saving, maintenance and using of them are the main ethical, legal and jurisprudence concerns in Iran. Concerns regarding human reproduction or human cloning, breach of human dignity, genetic manipulation and probability of tumorogenisity are observed in adult/somatic stem cells. Destruction of embryo to generate stem cell is an important matter in Iran. In this regards, obtaining stem cell from donated frozen embryos through infertility treatment that would be discarded is an acceptable solution in Iran for generation of embryo for research. Ethical, legal, and jurisprudence strategies for using adult/somatic stem cells are determination of ownership of stem cells, trade prohibition of human body, supervision on bio banks and information of Oversight Committee on Stem Cell Research. Recommendations to handle ethical issues for conducting stem cell research are well-designed studies, compliance codes of ethics in biomedical research (specifically codes of ethics on stem cell research, codes of ethics on clinical trials studies and codes of ethics on animals studies), appropriate collaboration with ethics committees and respecting of rights of participants (including both of human and animal rights) in research. In addition, there is a necessity for extending global networks of bioethics for strengthening communications within organizations at both the regional and international level, strengthening legislation systems, designing and establishing convenient collaborative educational courses at different levels. PMID:28462397

Effect of Dedifferentiation on Time to Mutation Acquisition in Stem Cell-Driven Cancers

PubMed Central

Jilkine, Alexandra; Gutenkunst, Ryan N.

2014-01-01

Accumulating evidence suggests that many tumors have a hierarchical organization, with the bulk of the tumor composed of relatively differentiated short-lived progenitor cells that are maintained by a small population of undifferentiated long-lived cancer stem cells. It is unclear, however, whether cancer stem cells originate from normal stem cells or from dedifferentiated progenitor cells. To address this, we mathematically modeled the effect of dedifferentiation on carcinogenesis. We considered a hybrid stochastic-deterministic model of mutation accumulation in both stem cells and progenitors, including dedifferentiation of progenitor cells to a stem cell-like state. We performed exact computer simulations of the emergence of tumor subpopulations with two mutations, and we derived semi-analytical estimates for the waiting time distribution to fixation. Our results suggest that dedifferentiation may play an important role in carcinogenesis, depending on how stem cell homeostasis is maintained. If the stem cell population size is held strictly constant (due to all divisions being asymmetric), we found that dedifferentiation acts like a positive selective force in the stem cell population and thus speeds carcinogenesis. If the stem cell population size is allowed to vary stochastically with density-dependent reproduction rates (allowing both symmetric and asymmetric divisions), we found that dedifferentiation beyond a critical threshold leads to exponential growth of the stem cell population. Thus, dedifferentiation may play a crucial role, the common modeling assumption of constant stem cell population size may not be adequate, and further progress in understanding carcinogenesis demands a more detailed mechanistic understanding of stem cell homeostasis. PMID:24603301

PGE2 /EP4 Signaling Controls the Transfer of the Mammary Stem Cell State by Lipid Rafts in Extracellular Vesicles.

PubMed

Lin, Meng-Chieh; Chen, Shih-Yin; Tsai, Ho-Min; He, Pei-Lin; Lin, Yen-Chun; Herschman, Harvey; Li, Hua-Jung

2017-02-01

Prostaglandin E 2 (PGE 2 )-initiated signaling contributes to stem cell homeostasis and regeneration. However, it is unclear how PGE 2 signaling controls cell stemness. This study identifies a previously unknown mechanism by which PGE 2 /prostaglandin E receptor 4 (EP 4 ) signaling regulates multiple signaling pathways (e.g., PI3K/Akt signaling, TGFβ signaling, Wnt signaling, EGFR signaling) which maintain the basal mammary stem cell phenotype. A shift of basal mammary epithelial stem cells (MaSCs) from a mesenchymal/stem cell state to a non-basal-MaSC state occurs in response to prostaglandin E receptor 4 (EP 4 ) antagonism. EP 4 antagonists elicit release of signaling components, by controlling their trafficking into extracellular vesicles/exosomes in a lipid raft/caveolae-dependent manner. Consequently, EP 4 antagonism indirectly inactivates, through induced extracellular vesicle/exosome release, pathways required for mammary epithelial stem cell homeostasis, e.g. canonical/noncanonical Wnt, TGFβ and PI3K/Akt pathways. EP 4 antagonism causes signaling receptors and signaling components to shift from non-lipid raft fractions to lipid raft fractions, and to then be released in EP 4 antagonist-induced extracellular vesicles/exosomes, resulting in the loss of the stem cell state by mammary epithelial stem cells. In contrast, luminal mammary epithelial cells can acquire basal stem cell properties following ingestion of EP 4 antagonist-induced stem cell extracellular vesicles/exosomes, and can then form mammary glands. These findings demonstrate that PGE 2 /EP 4 signaling controls homeostasis of mammary epithelial stem cells through regulating extracellular vesicle/exosome release. Reprogramming of mammary epithelial cells can result from EP 4 -mediated stem cell property transfer by extracellular vesicles/exosomes containing caveolae-associated proteins, between mammary basal and luminal epithelial cells. Stem Cells 2017;35:425-444. © 2016 The Authors STEM CELLS published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

The Drosophila ovarian and testis stem cell niches: similar somatic stem cells and signals.

PubMed

Decotto, Eva; Spradling, Allan C

2005-10-01

The stem cell niches at the apex of Drosophila ovaries and testes have been viewed as distinct in two major respects. While both contain germline stem cells, the testis niche also contains "cyst progenitor" stem cells, which divide to produce somatic cells that encase developing germ cells. Moreover, while both niches utilize BMP signaling, the testis niche requires a key JAK/STAT signal. We now show, by lineage marking, that the ovarian niche also contains a second type of stem cell. These "escort stem cells" morphologically resemble testis cyst progenitor cells and their daughters encase developing cysts before undergoing apoptosis at the time of follicle formation. In addition, we show that JAK/STAT signaling also plays a critical role in ovarian niche function, and acts within escort cells. These observations reveal striking similarities in the stem cell niches of male and female gonads, and suggest that they are largely governed by common mechanisms.

Placenta-an alternative source of stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matikainen, Tiina; Laine, Jarmo

2005-09-01

The two most promising practical applications of human stem cells are cellular replacement therapies in human disease and toxicological screening of candidate drug molecules. Both require a source of human stem cells that can be isolated, purified, expanded in number and differentiated into the cell type of choice in a controlled manner. Currently, uses of both embryonic and adult stem cells are investigated. While embryonic stem cells are pluripotent and can differentiate into any specialised cell type, their use requires establishment of embryonic stem cell lines using the inner cell mass of an early pre-implantation embryo. As the blastocyst ismore » destroyed during the process, ethical issues need to be carefully considered. The use of embryonic stem cells is also limited by the difficulties in growing large numbers of the cells without inducing spontaneous differentiation, and the problems in controlling directed differentiation of the cells. The use of adult stem cells, typically derived from bone marrow, but also from other tissues, is ethically non-controversial but their differentiation potential is more limited than that of the embryonic stem cells. Since human cord blood, umbilical cord, placenta and amnion are normally discarded at birth, they provide an easily accessible alternative source of stem cells. We review the potential and current status of the use of adult stem cells derived from the placenta or umbilical cord in therapeutic and toxicological applications.« less

Pluripotent stem cells and reprogrammed cells in farm animals.

PubMed

Nowak-Imialek, Monika; Kues, Wilfried; Carnwath, Joseph W; Niemann, Heiner

2011-08-01

Pluripotent cells are unique because of their ability to differentiate into the cell lineages forming the entire organism. True pluripotent stem cells with germ line contribution have been reported for mice and rats. Human pluripotent cells share numerous features of pluripotentiality, but confirmation of their in vivo capacity for germ line contribution is impossible due to ethical and legal restrictions. Progress toward derivation of embryonic stem cells from domestic species has been made, but the derived cells were not able to produce germ line chimeras and thus are termed embryonic stem-like cells. However, domestic animals, in particular the domestic pig (Sus scrofa), are excellent large animals models, in which the clinical potential of stem cell therapies can be studied. Reprogramming technologies for somatic cells, including somatic cell nuclear transfer, cell fusion, in vitro culture in the presence of cell extracts, in vitro conversion of adult unipotent spermatogonial stem cells into germ line derived pluripotent stem cells, and transduction with reprogramming factors have been developed with the goal of obtaining pluripotent, germ line competent stem cells from domestic animals. This review summarizes the present state of the art in the derivation and maintenance of pluripotent stem cells in domestic animals.

Information on Stem Cell Research

MedlinePlus

... of stem cells share similar properties there are differences as well. For example, ES cells and iPS cells are able to differentiate into any type of cell, whereas adult stem cells are more restricted in their potential. The promise of all stem cells for use ...

The Development of Stem Cell-Based Treatment for Liver Failure.

PubMed

Zhu, Tiantian; Li, Yuwen; Guo, Yusheng; Zhu, Chuanlong

2017-01-01

Liver failure is a devastating clinical syndrome with a persistently mortality rate despite advanced care. Orthotopic liver transplantation protected patients from hepatic failure. Yet, limitations including postoperative complications, high costs, and shortages of donor organs defect its application. The development of stem cell therapy complements the deficiencies of liver transplantation, due to the inherent ability of stem cells to proliferate and differentiate. Understand the source of stem cells, as well as the advantages and disadvantages of stem cell therapy. Based on published papers, we discussed the cell sources and therapeutic effect of stem cells. We also summarized the pros and cons, as well as optimization of stem cell-based treatment. Finally outlook future prospects of stem cell therapy. Stem cells may be harvested from a variety of human tissues, and then used to promote the convalescence of hepatocellular function. The emergence of the co-cultured system, tissueengineered technology and genetic modfication has further enhanced the functionality of stem cells. However, the tumorigenicity, the low survival rate and the scarcity of long-term treatment effect are obstacles for the further development of stem cell therapy. In this review, we highlight current research findings and present the future prospects in the area of stem cell-based treatment for liver failure. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

76 FR 11491 - Advisory Council on Blood Stem Cell Transplantation; Request for Nominations for Voting Members

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-02

... Council on Blood Stem Cell Transplantation; Request for Nominations for Voting Members AGENCY: Health... on Blood Stem Cell Transplantation. The Advisory Council on Blood Stem Cell Transplantation was...: Nominations should be submitted to the Executive Secretary, Advisory Council on Blood Stem Cell...

3 CFR - Guidelines for Human Stem Cell Research

Code of Federal Regulations, 2010 CFR

2010-01-01

... 3 The President 1 2010-01-01 2010-01-01 false Guidelines for Human Stem Cell Research Presidential Documents Other Presidential Documents Memorandum of July 30, 2009 Guidelines for Human Stem Cell Research..., scientifically worthy human stem cell research, including human embryonic stem cell research, to the extent...

Aging, metabolism and stem cells: Spotlight on muscle stem cells.

PubMed

García-Prat, Laura; Muñoz-Cánoves, Pura

2017-04-15

All tissues and organs undergo a progressive regenerative decline as they age. This decline has been mainly attributed to loss of stem cell number and/or function, and both stem cell-intrinsic changes and alterations in local niches and/or systemic environment over time are known to contribute to the stem cell aging phenotype. Advancing in the molecular understanding of the deterioration of stem cell cells with aging is key for targeting the specific causes of tissue regenerative dysfunction at advanced stages of life. Here, we revise exciting recent findings on why stem cells age and the consequences on tissue regeneration, with a special focus on regeneration of skeletal muscle. We also highlight newly identified common molecular pathways affecting diverse types of aging stem cells, such as altered proteostasis, metabolism, or senescence entry, and discuss the questions raised by these findings. Finally, we comment on emerging stem cell rejuvenation strategies, principally emanating from studies on muscle stem cells, which will surely burst tissue regeneration research for future benefit of the increasing human aging population. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

In vitro spatially organizing the differentiation in individual multicellular stem cell aggregates.

PubMed

Qi, Hao; Huang, Guoyou; Han, Yu Long; Lin, Wang; Li, Xiujun; Wang, Shuqi; Lu, Tian Jian; Xu, Feng

2016-01-01

With significant potential as a robust source to produce specific somatic cells for regenerative medicine, stem cells have attracted increasing attention from both academia and government. In vivo, stem cell differentiation is a process under complicated regulations to precisely build tissue with unique spatial structures. Since multicellular spheroidal aggregates of stem cells, commonly called as embryoid bodies (EBs), are considered to be capable of recapitulating the events in early stage of embryonic development, a variety of methods have been developed to form EBs in vitro for studying differentiation of embryonic stem cells. The regulation of stem cell differentiation is crucial in directing stem cells to build tissue with the correct spatial architecture for specific functions. However, stem cells within the three-dimensional multicellular aggregates undergo differentiation in a less unpredictable and spatially controlled manner in vitro than in vivo. Recently, various microengineering technologies have been developed to manipulate stem cells in vitro in a spatially controlled manner. Herein, we take the spotlight on these technologies and researches that bring us the new potential for manipulation of stem cells for specific purposes.

Stem cells in nephrology: present status and future.

PubMed

Watorek, Ewa; Klinger, Marian

2006-01-01

Stem cell biology is currently developing rapidly because of the potential therapeutic utility of stem cells. The ability to acquire any desired phenotype raises hope for regenerative therapies. Manipulation of these cells is a potentially valuable tool; however, the mechanisms of stem cell differentiation and plasticity are currently beyond our control. In the field of nephrology, the presence of adult kidney stem cells has been debated. Renal adult stem cells may be descendants of some early kidney progenitors, or may be derived from bone marrow. Evidence of a hematopoietic stem-cell contribution to renal repair encourages the possibility of bone marrow or stem cell transplantation as a means of treating autoimmune glomerulopathies. The transplantation of fetal kidney tissue containing renal progenitors, which then develop into functional nephrons, is a step towards renal regeneration. According to recent reports, the development of functional nephrons from human mesenchymal stem cells in rodent whole-embryo culture is possible. Establishing in vitro self organs from autologous stem cells would be a promising therapeutic solution in light of the shortage of allogenic organs and the unresolved problem of chronic allograft rejection.

Socializing with the neighbors: stem cells and their niche.

PubMed

Fuchs, Elaine; Tumbar, Tudorita; Guasch, Geraldine

2004-03-19

The potential of stem cells in regenerative medicine relies upon removing them from their natural habitat, propagating them in culture, and placing them into a foreign tissue environment. To do so, it is essential to understand how stem cells interact with their microenvironment, the so-called stem cell niche, to establish and maintain their properties. In this review, we examine adult stem cell niches and their impact on stem cell biology.

Stem Cells News Update: A Personal Perspective

PubMed Central

Wong, SC

2013-01-01

This article is a follow-up to a previous Commentary published in 2011. It updates some of the events mentioned in that Commentary and continues with more interesting and exciting news on stem cell research and the emerging field of Regenerative Medicine. Some of the news includes: 1) the 2012 Nobel Prize for Medicine awarded to John B. Gurdon and Shinya Yamanaka; 2) the cloning of human embryonic stem cells; 3) the continued search for truly pluripotent adult stem cells via in vitro and in vivo protocols; 4) the breakthrough in organ replacements; 5) the global stem cell race; 6) the global stem cell cryo-preservation business; 7) the worldwide stem cell donor registries, and 8) the issue of government regulation on stem cell therapy. PMID:24778557

Stem cells news update: a personal perspective.

PubMed

Wong, Sc

2013-12-01

This article is a follow-up to a previous Commentary published in 2011. It updates some of the events mentioned in that Commentary and continues with more interesting and exciting news on stem cell research and the emerging field of Regenerative Medicine. Some of the news includes: 1) the 2012 Nobel Prize for Medicine awarded to John B. Gurdon and Shinya Yamanaka; 2) the cloning of human embryonic stem cells; 3) the continued search for truly pluripotent adult stem cells via in vitro and in vivo protocols; 4) the breakthrough in organ replacements; 5) the global stem cell race; 6) the global stem cell cryo-preservation business; 7) the worldwide stem cell donor registries, and 8) the issue of government regulation on stem cell therapy.

Platelet-rich plasma derived growth factors contribute to stem cell differentiation in musculoskeletal regeneration

NASA Astrophysics Data System (ADS)

Qian, Yun; Han, Qixin; Chen, Wei; Song, Jialin; Zhao, Xiaotian; Ouyang, Yuanming; Yuan, Weien; Fan, Cunyi

2017-10-01

Stem cell treatment and platelet-rich plasma (PRP) therapy are two significant issues in regenerative medicine. Stem cells such as bone marrow mesenchymal stem cells, adipose-derived stem cells and periodontal ligament stem cells can be successfully applied in the field of tissue regeneration. PRP, a natural product isolated from whole blood, can secrete multiple growth factors (GFs) for regulating physiological activities. These GFs can stimulate proliferation and differentiation of different stem cells in injury models. Therefore, combination of both agents receives wide expectations in regenerative medicine, especially in bone, cartilage and tendon repair. In this review, we thoroughly discussed the interaction and underlying mechanisms of platelet-rich plasma derived growth factors with stem cells, and assessed their functions in cell differentiation for musculoskeletal regeneration.

Elements of the niche for adult stem cell expansion

PubMed Central

Redondo, Patricia A; Pavlou, Marina; Loizidou, Marilena; Cheema, Umber

2017-01-01

Adult stem cells are crucial for tissue homeostasis. These cells reside within exclusive locations in tissues, termed niches, which protect adult stem cell fidelity and regulate their many functions through biophysical-, biochemical- and cellular-mediated mechanisms. There is a growing understanding of how these mechanisms and their components contribute towards maintaining stem cell quiescence, self-renewal, expansion and differentiation patterns. In vitro expansion of adult stem cells is a powerful tool for understanding stem cell biology, and for tissue engineering and regenerative medicine applications. However, it is technically challenging, since adult stem cell removal from their native microenvironment has negative repercussions on their sustainability. In this review, we overview specific elements of the biomimetic niche and how recreating such elements can help in vitro propagation of adult stem cells. PMID:28890779

Platelet-Rich Plasma Derived Growth Factors Contribute to Stem Cell Differentiation in Musculoskeletal Regeneration.

PubMed

Qian, Yun; Han, Qixin; Chen, Wei; Song, Jialin; Zhao, Xiaotian; Ouyang, Yuanming; Yuan, Weien; Fan, Cunyi

2017-01-01

Stem cell treatment and platelet-rich plasma (PRP) therapy are two significant issues in regenerative medicine. Stem cells such as bone marrow mesenchymal stem cells, adipose-derived stem cells and periodontal ligament stem cells can be successfully applied in the field of tissue regeneration. PRP, a natural product isolated from whole blood, can secrete multiple growth factors (GFs) for regulating physiological activities. These GFs can stimulate proliferation and differentiation of different stem cells in injury models. Therefore, combination of both agents receives wide expectations in regenerative medicine, especially in bone, cartilage and tendon repair. In this review, we thoroughly discussed the interaction and underlying mechanisms of PRP derived GFs with stem cells, and assessed their functions in cell differentiation for musculoskeletal regeneration.

Elements of the niche for adult stem cell expansion.

PubMed

Redondo, Patricia A; Pavlou, Marina; Loizidou, Marilena; Cheema, Umber

2017-01-01

Adult stem cells are crucial for tissue homeostasis. These cells reside within exclusive locations in tissues, termed niches, which protect adult stem cell fidelity and regulate their many functions through biophysical-, biochemical- and cellular-mediated mechanisms. There is a growing understanding of how these mechanisms and their components contribute towards maintaining stem cell quiescence, self-renewal, expansion and differentiation patterns. In vitro expansion of adult stem cells is a powerful tool for understanding stem cell biology, and for tissue engineering and regenerative medicine applications. However, it is technically challenging, since adult stem cell removal from their native microenvironment has negative repercussions on their sustainability. In this review, we overview specific elements of the biomimetic niche and how recreating such elements can help in vitro propagation of adult stem cells.

Stem cell maintenance by manipulating signaling pathways: past, current and future

PubMed Central

Chen, Xi; Ye, Shoudong; Ying, Qi-Long

2015-01-01

Pluripotent stem cells only exist in a narrow window during early embryonic development, whereas multipotent stem cells are abundant throughout embryonic development and are retainedin various adult tissues and organs. While pluripotent stem cell lines have been established from several species, including mouse, rat, and human, it is still challenging to establish stable multipotent stem cell lines from embryonic or adult tissues. Based on current knowledge, we anticipate that by manipulating extrinsic and intrinsic signaling pathways, most if not all types of stem cells can be maintained in a long-term culture. In this article, we summarize current culture conditions established for the long-term maintenance of authentic pluripotent and multipotent stem cells and the signaling pathways involved. We also discuss the general principles of stem cell maintenance and propose several strategies on the establishment of novel stem cell lines through manipulation of signaling pathways. [BMB Reports 2015; 48(12): 668-676] PMID:26497581

Stem cells and female reproduction.

PubMed

Du, Hongling; Taylor, Hugh S

2009-02-01

Several recent findings in stem cell biology have resulted in new opportunities for the treatment of reproductive disease. Endometrial regeneration can be driven by bone marrow derived stem cells. This finding has potential implications for the treatment of uterine disorders. It also supports a new theory for the etiology of endometriosis. The ovaries have been shown to contain stem cells that form oocytes in adults and can be cultured in vitro to develop mature oocytes. Stem cells from the fetus have been demonstrated to lead to microchimerism in the mother and implicated in several maternal diseases. Additionally the placenta may be another source of hematopoietic stem cell. Finally endometrial derived stem cells have been demonstrated to differentiate into non-reproductive tissues. While we are just beginning to understand stem cells and many key questions remain, the potential advantages of stem cells in reproductive biology and medicine are apparent.

The potential of nanofibers in tissue engineering and stem cell therapy.

PubMed

Gholizadeh-Ghaleh Aziz, Shiva; Gholizadeh-Ghaleh Aziz, Sara; Akbarzadeh, Abolfazl

2016-08-01

Electrospinning is a technique in which materials in solution are shaped into continuous nano- and micro-sized fibers. Combining stem cells with biomaterial scaffolds and nanofibers affords a favorable approach for bone tissue engineering, stem cell growth and transfer, ocular surface reconstruction, and treatment of congenital corneal diseases. This review seeks to describe the current examples of the use of scaffolds in stem cell therapy. Stem cells are classified as adult or embryonic stem (ES) cells, and the advantages and drawbacks of each group are detailed. The nanofibers and scaffolds are further classified in Tables I and II , which describe specific examples from the literature. Finally, the current applications of biomaterial scaffolds containing stem cells for tissue engineering applications are presented. Overall, this review seeks to give an overview of the biomaterials available for use in combination with stem cells, and the application of nanofibers in stem cell therapy.

The stem cell patent landscape as relevant to cancer vaccines.

PubMed

Wang, Shyh-Jen

2011-10-01

Cancer vaccine targeting cancer stem cells is proposed to serve as a potent immunotherapy. Thus, it would be useful to examine the main trends in stem cell patenting activity as a guide for those seeking to develop such cancer vaccines. We found that a substantial number of stem cell patents were granted up to the end of 2010, including ~2000 issued in the US. Many of these have been filed since 2001, including 7,551 applications in the US. Stem cell development, as evidenced by the numbers of PubMed articles, has matured steadily in recent years. However, the other metrics, such as the number of patent applications, the technology-science linkage and the number of patent assignees, have been stagnant. Moreover, the ownership of stem cell patents is still quiet fragmented across multiple organizations, and the number of stem cell patent assignees from the business sector has not increased significantly. Academic and nonprofit institutions not only account for a large share of stem cell patents but also apply for patents continually. Based on this analysis, the strength of stem cell resources seems to remain stagnant in recent years due to the ban on government funding of embryonic stem cell research. Furthermore, the patent prosecution or technical barriers in the field of stem cells would be another main reason that the number of US-issued stem cell patents for each application have been in gradual decline since 2000. Therefore, we consider stem cell technology to still be under development.

Fraudsters operate and officialdom turns a blind eye: a proposal for controlling stem cell therapy in China.

PubMed

Jiang, Li; Dong, Bing He

2016-09-01

Stem cell tourism-the flow of patients from home countries to destination countries to obtain stem cell treatment-is a growing business in China. Many concerns have been raised regarding fraudsters that operate unsafe stem cell therapies and an officialdom that turns a blind eye to the questionable technology. The Chinese regulatory approach to stem cell research is based on Guidelines and Administrative Measures, rather than legislation, and may have no binding force on certain institutions, such as military hospitals. There is no liability and traceability system and no visible set of penalties for non-compliance in the stem cell legal framework. In addition to the lack of safety and efficacy systems in the regulations, no specific expert authority has been established to monitor stem cell therapy to date. Recognizing the global nature of stem cell tourism, this article argues that resolving stem cell tourism issues may require not only the Chinese government but also an international mechanism for transparency and ethical oversight. A stringent set of international regulations that govern stem cell therapies can encourage China to improve stem cell regulation and enforcement to fulfill its obligations. Through an international consensus, a minimum standard for clinical stem cell research and a central enforcement system will be provided. As a result, rogue clinics that conduct unauthorized stem cell therapies can be penalized, and countries that are reluctant to implement the reconciled regulations should be sanctioned.

Epigenetic Control of Stem Cell Potential During Homeostasis, Aging, and Disease

PubMed Central

Beerman, Isabel; Rossi, Derrick J.

2015-01-01

Stem cell decline is an important cellular driver of aging-associated pathophysiology in multiple tissues. Epigenetic regulation is central to establishing and maintaining stem cell function, and emerging evidence indicates that epigenetic dysregulation contributes to the altered potential of stem cells during aging. Unlike terminally differentiated cells, the impact of epigenetic dysregulation in stem cells is propagated beyond self; alterations can be heritably transmitted to differentiated progeny, in addition to being perpetuated and amplified within the stem cell pool through self-renewal divisions. This review focuses on recent studies examining epigenetic regulation of tissue-specific stem cells in homeostasis, aging, and aging-related disease. PMID:26046761

Attitude of A Sample of Iranian Researchers toward The Future of Stem Cell Research.

PubMed

Lotfipanah, Mahdi; Azadeh, Fereydoon; Totonchi, Mehdi; Omani-Samani, Reza

2018-10-01

Stem cells that have unlimited proliferation potential as well as differentiation potency are considered to be a promising future treatment method for incurable diseases. The aim of the present study is to evaluate the future trend of stem cell researches from researchers' viewpoints. This was a cross-sectional descriptive study on researchers involved in stem cell research at Royan Institute. We designed a questionnaire using a qualitative study based on expert opinion and a literature review. Content validity was performed using three rounds of the Delphi method with experts. Face validity was undertaken by a Persian literature expert and a graphics designer. The questionnaire was distributed among 150 researchers involved in stem cell studies in Royan Institute biology laboratories. We collected 138 completed questionnaires. The mean age of participants was 31.13 ± 5.8 years; most (60.9%) were females. Participants (76.1%) considered the budget to be the most important issue in stem cell research, 79.7% needed financial support from the government, and 77.5% felt that charities could contribute substantially to stem cell research. A total of 90.6% of participants stated that stem cells should lead to commercial usage which could support future researches (86.2%). The aim of stem cell research was stipulated as increasing health status of the society according to 92.8% of the participants. At present, among cell types, importance was attached to cord blood and adult stem cells. Researchers emphasized the importance of mesenchymal stem cells (MSCs) rather than hematopoietic stem cells (HSCs, 57.73%). The prime priorities were given to cancer so that stem cell research could be directed to sphere stem cell research whereas the least preference was given to skin research. Regenerative medicine is considered the future of stem cell research with emphasis on application of these cells, especially in cancer treatment. Copyright© by Royan Institute. All rights reserved.

Translating stem cell research: challenges at the research frontier.

PubMed

Magnus, David

2010-01-01

This paper will address the translation of basic stem cell research into clinical research. While "stem cell" trials are sometimes used to describe established practices of bone marrow transplantation or transplantation of primary cells derived from bone marrow, for the purposes of this paper, I am primarily focusing on stem cell trials which are far less established, including use of hESC derived stem cells. The central ethical challenges in stem cell clinical trials arise in frontier research, not in standard, well-established areas of research.

Murine hepatocellular carcinoma derived stem cells reveal epithelial-to-mesenchymal plasticity.

PubMed

Jayachandran, Aparna; Shrestha, Ritu; Dhungel, Bijay; Huang, I-Tao; Vasconcelos, Marianna Yumi Kawashima; Morrison, Brian J; Ramlogan-Steel, Charmaine A; Steel, Jason C

2017-09-26

To establish a model to enrich and characterize stem-like cells from murine normal liver and hepatocellular carcinoma (HCC) cell lines and to further investigate stem-like cell association with epithelial-to-mesenchymal transition (EMT). In this study, we utilized a stem cell conditioned serum-free medium to enrich stem-like cells from mouse HCC and normal liver cell lines, Hepa 1-6 and AML12, respectively. We isolated the 3-dimensional spheres and assessed their stemness characteristics by evaluating the RNA levels of stemness genes and a cell surface stem cell marker by quantitative reverse transcriptase-PCR (qRT-PCR). Next, we examined the relationship between stem cells and EMT using qRT-PCR. Three-dimensional spheres were enriched by culturing murine HCC and normal hepatocyte cell lines in stem cell conditioned serum-free medium supplemented with epidermal growth factor, basic fibroblast growth factor and heparin sulfate. The 3-dimensional spheres had enhanced stemness markers such as Klf4 and Bmi1 and hepatic cancer stem cell (CSC) marker Cd44 compared to parental cells grown as adherent cultures. We report that epithelial markers E-cadherin and ZO-1 were downregulated, while mesenchymal markers Vimentin and Fibronectin were upregulated in 3-dimensional spheres. The 3-dimensional spheres also exhibited changes in expression of Snai , Zeb and Twist family of EMT transcription factors. Our novel method successfully enriched stem-like cells which possessed an EMT phenotype. The isolation and characterization of murine hepatic CSCs could establish a precise target for the development of more effective therapies for HCC.

Wnt/β-Catenin Signaling Determines the Vasculogenic Fate of Postnatal Mesenchymal Stem Cells.

PubMed

Zhang, Zhaocheng; Nör, Felipe; Oh, Min; Cucco, Carolina; Shi, Songtao; Nör, Jacques E

2016-06-01

Vasculogenesis is the process of de novo blood vessel formation observed primarily during embryonic development. Emerging evidence suggest that postnatal mesenchymal stem cells are capable of recapitulating vasculogenesis when these cells are engaged in tissue regeneration. However, the mechanisms underlining the vasculogenic differentiation of mesenchymal stem cells remain unclear. Here, we used stem cells from human permanent teeth (dental pulp stem cells [DPSC]) or deciduous teeth (stem cells from human exfoliated deciduous teeth [SHED]) as models of postnatal primary human mesenchymal stem cells to understand mechanisms regulating their vasculogenic fate. GFP-tagged mesenchymal stem cells seeded in human tooth slice/scaffolds and transplanted into immunodeficient mice differentiate into human blood vessels that anastomize with the mouse vasculature. In vitro, vascular endothelial growth factor (VEGF) induced the vasculogenic differentiation of DPSC and SHED via potent activation of Wnt/β-catenin signaling. Further, activation of Wnt signaling is sufficient to induce the vasculogenic differentiation of postnatal mesenchymal stem cells, while Wnt inhibition blocked this process. Notably, β-catenin-silenced DPSC no longer differentiate into endothelial cells in vitro, and showed impaired vasculogenesis in vivo. Collectively, these data demonstrate that VEGF signaling through the canonical Wnt/β-catenin pathway defines the vasculogenic fate of postnatal mesenchymal stem cells. Stem Cells 2016;34:1576-1587. © 2016 AlphaMed Press.

MiR-7 inhibited peripheral nerve injury repair by affecting neural stem cells migration and proliferation through cdc42.

PubMed

Zhou, Nan; Hao, Shuang; Huang, Zongqiang; Wang, Weiwei; Yan, Penghui; Zhou, Wei; Zhu, Qihang; Liu, Xiaokang

2018-01-01

Objective Neural stem cells play an important role in the recovery and regeneration of peripheral nerve injury, and the microRNA-7 (miR-7) regulates differentiation of neural stem cells. This study aimed to explore the role of miR-7 in neural stem cells homing and proliferation and its influence on peripheral nerve injury repair. Methods The mice model of peripheral nerve injury was created by segmental sciatic nerve defect (sciatic nerve injury), and neural stem cells treatment was performed with a gelatin hydrogel conduit containing neural stem cells inserted into the sciatic nerve injury mice. The Sciatic Function Index was used to quantify sciatic nerve functional recovery in the mice. The messenger RNA and protein expression were detected by reverse transcription polymerase chain reaction and Western blot, respectively. Luciferase reporter assay was used to confirm the binding between miR-7 and the 3'UTR of cell division cycle protein 42 (cdc42). The neural stem cells migration and proliferation were analyzed by transwell assay and a Cell-LightTM EdU DNA Cell Proliferation kit, respectively. Results Neural stem cells treatment significantly promoted nerve repair in sciatic nerve injury mice. MiR-7 expression was decreased in sciatic nerve injury mice with neural stem cells treatment, and miR-7 mimic transfected into neural stem cells suppressed migration and proliferation, while miR-7 inhibitor promoted migration and proliferation. The expression level and effect of cdc42 on neural stem cells migration and proliferation were opposite to miR-7, and the luciferase reporter assay proved that cdc42 was a target of miR-7. Using co-transfection into neural stem cells, we found pcDNA3.1-cdc42 and si-cdc42 could reverse respectively the role of miR-7 mimic and miR-7 inhibitor on neural stem cells migration and proliferation. In addition, miR-7 mimic-transfected neural stem cells could abolish the protective role of neural stem cells on peripheral nerve injury. Conclusion MiR-7 inhibited peripheral nerve injury repair by affecting neural stem cells migration and proliferation through cdc42.

International Society for Stem Cell Research

MedlinePlus

... cell and regenerative medicine community. More stem cell research Take a closer look Recent Blogs View All ... nonprofit organization & the voice of the stem cell research community The International Society for Stem Cell Research ( ...

Stem cell regenerative potential combined with nanotechnology and tissue engineering for myocardial regeneration.

PubMed

Calin, Manuela; Stan, Daniela; Simion, Viorel

2013-07-01

The stem cell-based therapy for post-infarction myocardial regeneration has been introduced more than a decade ago, but the functional improvement obtained is limited due to the poor retention and short survival rate of transplanted cells into the damaged myocardium. More recently, the emerging nanotechnology concepts for advanced diagnostics and therapy provide promising opportunities of using stem cells for myocardial regeneration. In this paper will be provided an overview of the use of nanotechnology approaches in stem cell research for: 1) cell labeling to track the distribution of stem cells after transplantation, 2) nanoparticle-mediated gene delivery to stem cells to promote their homing, engraftment, survival and differentiation in the ischemic myocardium and 3) obtaining of bio-inspired materials to provide suitable myocardial scaffolds for delivery of stem cells or stem cell-derived factors.

Role of stem cell derived exosomes in tumor biology.

PubMed

Sharma, Aman

2018-03-15

Exosomes are nano-scale messengers loaded with bio-molecular cargo of RNA, DNA, and Proteins. As a master regulator of cellular signaling, stem cell (both normal, and cancer stem cells) secreted exosome orchestrate various autocrine and paracrine functions which alter tumor micro-environment, growth and progression. Exosomes secreted by one of the two important stem cell phenotypes in cancers a) Mesenchymal stem cells, and b) Cancer stem cells not only promote cancerous growth but also impart therapy resistance in cancer cells. In tumors, normal or mesenchymal stem cell (MSCs) derived exosomes (MSC-exo) modulate tumor hallmarks by delivering unique miRNA species to neighboring cells and help in tumor progression. Apart from regulating tumor cell fate, MSC-exo are also capable of inducing physiological processes, for example, angiogenesis, metastasis and so forth. Similarly, cancer stem cells (CSCs) derived exosomes (CSC-exo) contain stemness-specific proteins, self-renewal promoting regulatory miRNAs, and survival factors. CSC-exo specific cargo maintains tumor heterogeneity and alters tumor progression. In this review we critically discuss the importance of stem cell specific exosomes in tumor cell signaling pathways with their role in tumor biology. © 2017 UICC.

Stochasticity and Spatial Interaction Govern Stem Cell Differentiation Dynamics

NASA Astrophysics Data System (ADS)

Smith, Quinton; Stukalin, Evgeny; Kusuma, Sravanti; Gerecht, Sharon; Sun, Sean X.

2015-07-01

Stem cell differentiation underlies many fundamental processes such as development, tissue growth and regeneration, as well as disease progression. Understanding how stem cell differentiation is controlled in mixed cell populations is an important step in developing quantitative models of cell population dynamics. Here we focus on quantifying the role of cell-cell interactions in determining stem cell fate. Toward this, we monitor stem cell differentiation in adherent cultures on micropatterns and collect statistical cell fate data. Results show high cell fate variability and a bimodal probability distribution of stem cell fraction on small (80-140 μm diameter) micropatterns. On larger (225-500 μm diameter) micropatterns, the variability is also high but the distribution of the stem cell fraction becomes unimodal. Using a stochastic model, we analyze the differentiation dynamics and quantitatively determine the differentiation probability as a function of stem cell fraction. Results indicate that stem cells can interact and sense cellular composition in their immediate neighborhood and adjust their differentiation probability accordingly. Blocking epithelial cadherin (E-cadherin) can diminish this cell-cell contact mediated sensing. For larger micropatterns, cell motility adds a spatial dimension to the picture. Taken together, we find stochasticity and cell-cell interactions are important factors in determining cell fate in mixed cell populations.

NANOS2 acts downstream of glial cell line-derived neurotrophic factor signaling to suppress differentiation of spermatogonial stem cells.

PubMed

Sada, Aiko; Hasegawa, Kazuteru; Pin, Pui Han; Saga, Yumiko

2012-02-01

Stem cells are maintained by both stem cell-extrinsic niche signals and stem cell-intrinsic factors. During murine spermatogenesis, glial cell line-derived neurotrophic factor (GDNF) signal emanated from Sertoli cells and germ cell-intrinsic factor NANOS2 represent key regulators for the maintenance of spermatogonial stem cells. However, it remains unclear how these factors intersect in stem cells to control their cellular state. Here, we show that GDNF signaling is essential to maintain NANOS2 expression, and overexpression of Nanos2 can alleviate the stem cell loss phenotype caused by the depletion of Gfra1, a receptor for GDNF. By using an inducible Cre-loxP system, we show that NANOS2 expression is downregulated upon the conditional knockout (cKO) of Gfra1, while ectopic expression of Nanos2 in GFRA1-negative spermatogonia does not induce de novo GFRA1 expression. Furthermore, overexpression of Nanos2 in the Gfra1-cKO testes prevents precocious differentiation of the Gfra1-knockout stem cells and partially rescues the stem cell loss phenotypes of Gfra1-deficient mice, indicating that the stem cell differentiation can be suppressed by NANOS2 even in the absence of GDNF signaling. Taken together, we suggest that NANOS2 acts downstream of GDNF signaling to maintain undifferentiated state of spermatogonial stem cells. Copyright © 2011 AlphaMed Press.

Isolation and functional interrogation of adult human prostate epithelial stem cells at single cell resolution.

PubMed

Hu, Wen-Yang; Hu, Dan-Ping; Xie, Lishi; Li, Ye; Majumdar, Shyama; Nonn, Larisa; Hu, Hong; Shioda, Toshi; Prins, Gail S

2017-08-01

Using primary cultures of normal human prostate epithelial cells, we developed a novel prostasphere-based, label-retention assay that permits identification and isolation of stem cells at a single cell level. Their bona fide stem cell nature was corroborated using in vitro and in vivo regenerative assays and documentation of symmetric/asymmetric division. Robust WNT10B and KRT13 levels without E-cadherin or KRT14 staining distinguished individual stem cells from daughter progenitors in spheroids. Following FACS to isolate label-retaining stem cells from label-free progenitors, RNA-seq identified unique gene signatures for the separate populations which may serve as useful biomarkers. Knockdown of KRT13 or PRAC1 reduced sphere formation and symmetric self-renewal highlighting their role in stem cell maintenance. Pathways analysis identified ribosome biogenesis and membrane estrogen-receptor signaling enriched in stem cells with NF-ĸB signaling enriched in progenitors; activities that were biologically confirmed. Further, bioassays identified heightened autophagy flux and reduced metabolism in stem cells relative to progenitors. These approaches similarly identified stem-like cells from prostate cancer specimens and prostate, breast and colon cancer cell lines suggesting wide applicability. Together, the present studies isolate and identify unique characteristics of normal human prostate stem cells and uncover processes that maintain stem cell homeostasis in the prostate gland. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Materials as stem cell regulators

PubMed Central

Murphy, William L.; McDevitt, Todd C.; Engler, Adam J.

2014-01-01

The stem cell/material interface is a complex, dynamic microenvironment in which the cell and the material cooperatively dictate one another's fate: the cell by remodelling its surroundings, and the material through its inherent properties (such as adhesivity, stiffness, nanostructure or degradability). Stem cells in contact with materials are able to sense their properties, integrate cues via signal propagation and ultimately translate parallel signalling information into cell fate decisions. However, discovering the mechanisms by which stem cells respond to inherent material characteristics is challenging because of the highly complex, multicomponent signalling milieu present in the stem cell environment. In this Review, we discuss recent evidence that shows that inherent material properties may be engineered to dictate stem cell fate decisions, and overview a subset of the operative signal transduction mechanisms that have begun to emerge. Further developments in stem cell engineering and mechanotransduction are poised to have substantial implications for stem cell biology and regenerative medicine. PMID:24845994

Stem cells in genetically-engineered mouse models of prostate cancer

PubMed Central

Shibata, Maho; Shen, Michael M.

2015-01-01

The cancer stem cell model proposes that tumors have a hierarchical organization in which tumorigenic cells give rise to non-tumorigenic cells, with only a subset of stem-like cells able to propagate the tumor. In the case of prostate cancer, recent analyses of genetically engineered mouse (GEM) models have provided evidence supporting the existence of cancer stem cells in vivo. These studies suggest that cancer stem cells capable of tumor propagation exist at various stages of tumor progression from prostatic intraepithelial neoplasia (PIN) to advanced metastatic and castration-resistant disease. However, studies of stem cells in prostate cancer have been limited by available approaches for evaluating their functional properties in cell culture and transplantation assays. Given the role of the tumor microenvironment and the putative cancer stem cell niche, future studies using GEM models to analyze cancer stem cells in their native tissue microenvironment are likely to be highly informative. PMID:26341780

The evolution of chicken stem cell culture methods.

PubMed

Farzaneh, M; Attari, F; Mozdziak, P E; Khoshnam, S E

2017-12-01

1. The avian embryo is an excellent model for studying embryology and the production of pharmaceutical proteins in transgenic chickens. Furthermore, chicken stem cells have the potential for proliferation and differentiation and emerged as an attractive tool for various cell-based technologies. 2. The objective of these studies is the derivation and culture of these stem cells is the production of transgenic birds for recombinant biomaterials and vaccine manufacture, drug and cytotoxicity testing, as well as to gain insight into basic science, including cell tracking. 3. Despite similarities among the established chicken stem cell lines, fundamental differences have been reported between their culture conditions and applications. Recent conventional protocols used for expansion and culture of chicken stem cells mostly depend on feeder cells, serum-containing media and static culture. 4. Utilising chicken stem cells for generation of cell-based transgenic birds and a variety of vaccines requires large-scale cell production. However, scaling up the conventional adherent chicken stem cells is challenging and labour intensive. Development of a suspension cell culture process for chicken embryonic stem cells (cESCs), chicken primordial germ cells (PGCs) and chicken induced pluripotent stem cells (ciPSCs) will be an important advance for increasing the growth kinetics of these cells. 6. This review describes various approaches and suggestions to achieve optimal cell growth for defined chicken stem cells cultures and use in future manufacturing applications.

Development of hematopoietic stem and progenitor cells from human pluripotent stem cells.

PubMed

Chen, Tong; Wang, Fen; Wu, Mengyao; Wang, Zack Z

2015-07-01

Human pluripotent stem cells (hPSCs), including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), provide a new cell source for regenerative medicine, disease modeling, drug discovery, and preclinical toxicity screening. Understanding of the onset and the sequential process of hematopoietic cells from differentiated hPSCs will enable the achievement of personalized medicine and provide an in vitro platform for studying of human hematopoietic development and disease. During embryogenesis, hemogenic endothelial cells, a specified subset of endothelial cells in embryonic endothelium, are the primary source of multipotent hematopoietic stem cells. In this review, we discuss current status in the generation of multipotent hematopoietic stem and progenitor cells from hPSCs via hemogenic endothelial cells. We also review the achievements in direct reprogramming from non-hematopoietic cells to hematopoietic stem and progenitor cells. Further characterization of hematopoietic differentiation in hPSCs will improve our understanding of blood development and expedite the development of hPSC-derived blood products for therapeutic purpose. © 2015 Wiley Periodicals, Inc.

Therapeutic microparticles functionalized with biomimetic cardiac stem cell membranes and secretome

PubMed Central

Tang, Junnan; Shen, Deliang; Caranasos, Thomas George; Wang, Zegen; Vandergriff, Adam C.; Allen, Tyler A.; Hensley, Michael Taylor; Dinh, Phuong-Uyen; Cores, Jhon; Li, Tao-Sheng; Zhang, Jinying; Kan, Quancheng; Cheng, Ke

2017-01-01

Stem cell therapy represents a promising strategy in regenerative medicine. However, cells need to be carefully preserved and processed before usage. In addition, cell transplantation carries immunogenicity and/or tumourigenicity risks. Mounting lines of evidence indicate that stem cells exert their beneficial effects mainly through secretion (of regenerative factors) and membrane-based cell–cell interaction with the injured cells. Here, we fabricate a synthetic cell-mimicking microparticle (CMMP) that recapitulates stem cell functions in tissue repair. CMMPs carry similar secreted proteins and membranes as genuine cardiac stem cells do. In a mouse model of myocardial infarction, injection of CMMPs leads to the preservation of viable myocardium and augmentation of cardiac functions similar to cardiac stem cell therapy. CMMPs (derived from human cells) do not stimulate T-cell infiltration in immuno-competent mice. In conclusion, CMMPs act as ‘synthetic stem cells’ which mimic the paracrine and biointerfacing activities of natural stem cells in therapeutic cardiac regeneration. PMID:28045024

Stem cell plasticity enables hair regeneration following Lgr5+ cell loss.

PubMed

Hoeck, Joerg D; Biehs, Brian; Kurtova, Antonina V; Kljavin, Noelyn M; de Sousa E Melo, Felipe; Alicke, Bruno; Koeppen, Hartmut; Modrusan, Zora; Piskol, Robert; de Sauvage, Frederic J

2017-06-01

Under injury conditions, dedicated stem cell populations govern tissue regeneration. However, the molecular mechanisms that induce stem cell regeneration and enable plasticity are poorly understood. Here, we investigate stem cell recovery in the context of the hair follicle to understand how two molecularly distinct stem cell populations are integrated. Utilizing diphtheria-toxin-mediated cell ablation of Lgr5 + (leucine-rich repeat-containing G-protein-coupled receptor 5) stem cells, we show that killing of Lgr5 + cells in mice abrogates hair regeneration but this is reversible. During recovery, CD34 + (CD34 antigen) stem cells activate inflammatory response programs and start dividing. Pharmacological attenuation of inflammation inhibits CD34 + cell proliferation. Subsequently, the Wnt pathway controls the recovery of Lgr5 + cells and inhibition of Wnt signalling prevents Lgr5 + cell and hair germ recovery. Thus, our study uncovers a compensatory relationship between two stem cell populations and the underlying molecular mechanisms that enable hair follicle regeneration.

Incidence of Intraocular Pressure Elevation following Intravitreal Ranibizumab (Lucentis) for Age-related Macular Degeneration.

PubMed

Reis, Gustavo Msm; Grigg, John; Chua, Brian; Lee, Anne; Lim, Ridia; Higgins, Ralph; Martins, Alessandra; Goldberg, Ivan; Clement, Colin I

2017-01-01

The aim of this article is to evaluate the rate of patients developing sustained elevated intraocular pressure (IOP) after ranibizumab (Lucentis) intravitreal (IVT) injections. This is a retrospective study. Charts of 192 consecutive patients receiving Lucentis for age-related macular degeneration (AMD) were retrospectively reviewed. We enrolled patients with at least two IOP measurements between injections. Elevated IOP was defined as >21 mm Hg with an increase of at least 20% from baseline. Noninjected contralateral eyes of the same patient cohort were used as control. Primary outcome was defined as elevated IOP. Secondary outcomes were presence and type of glaucoma, number of injections, and time to IOP elevation. Elevated IOP occurred at a significantly higher rate in eyes receiving IVT ranibizumab (7.47%; n = 9) compared with control (0.93%; n = 1). Patients with preexisting glaucoma or ocular hypertension (OHT) were more likely to develop elevated IOP after IVT ranibizumab injection. Intravitreal ranibizumab injections are associated with sustained IOP elevation in some eyes. Reis GMSM, Grigg J, Chua B, Lee A, Lim R, Higgins R, Martins A, Goldberg I, Clement CI. The Incidence of Intraocular Pressure Elevation following Intravitreal Ranibizumab (Lucentis) for Age-related Macular Degeneration. J Curr Glaucoma Pract 2017;11(1):3-7.

CLINICAL EVALUATION OF THE RAPID ACCESS VITREAL INJECTION GUIDE: A Handheld Instrument for Assisting Intravitreal Injections.

PubMed

Han, Dennis P; McKenney, Kaitlin C; Kim, Judy E; Weinberg, David V; Musch, David C; Singh, Ravi S J

2017-04-01

The Rapid Access Vitreal Injection (RAVI) guide combines the function of an eyelid speculum and measuring caliper into a single instrument for assisting intravitreal injections. This study clinically evaluated the RAVI guide with respect to patient acceptance, complication rates, and operative goals. A prospective study was performed on 54 patients undergoing intravitreal injections using the RAVI guide (n = 32) or the speculum/caliper (n = 22). Device-related pain was assessed using the Wong-Baker scoring system, scaled from 0 (no pain) to 10 (agonizing pain). Mean device-related pain score did not differ significantly between the 2 groups, with scores of 0.6 and 0.7 for the RAVI guide and speculum groups, respectively. The rate of significant pain (score of ≥2) was twice as high in the speculum group (7 of 22, 32%) compared with the RAVI guide group (5 of 32, 16%), but this difference was not statistically significant (P = 0.19, Fisher's exact test). Operative goals of avoiding needle touch to lashes/lids and guiding needle insertion to the intended site were achieved in all patients. The RAVI guide appeared equivalent to the eyelid speculum in achieving operative goals, with similarly low pain scores. It has the potential for facilitating efficient, accurate, and safe intravitreal injections.

Mobile ultra-clean unidirectional airflow screen reduces air contamination in a simulated setting for intra-vitreal injection.

PubMed

Lapid-Gortzak, Ruth; Traversari, Roberto; van der Linden, Jan Willem; Lesnik Oberstein, Sarit Y; Lapid, Oren; Schlingemann, Reinier O

2017-02-01

The aim of this study is to determine whether the use of a mobile ultra-clean laminar airflow screen reduces the air-borne particle counts in the setting of a simulated procedure of an intra-vitreal injection. A mobile ultra-clean unidirectional airflow (UDF) screen was tested in a simulated procedure for intra-vitreal injections in a treatment room without mechanical ventilation. One UDF was passed over the instrument tray and the surgical area. The concentration of particles was measured in the background, over the instrument table, and next to the ocular area. The degree of protection was calculated at the instrument table and at the surgical site. Use of the UDF mobile screen reduced the mean particle concentration (particles > 0.3 microns) on the instrument table by a factor of at least 100.000 (p < 0.05), and over the patient's eye by at least a factor of 436 (p < 0.05), which in clinical practice translates into significantly reduced air contamination. Mobile UDF screen reduces the mean particle concentration substantially. The mobile UDF screen may therefore allow for a safer procedural environment for ambulatory care procedures such as intra-vitreal injections in treatment rooms.

Intravitreal injections: what do patients prefer? Analysis of patient's satisfaction and preferences about where to perform intravitreal injections.

PubMed

Rodríguez Ramírez, M; del Barrio Manso, M I; Martín Sánchez, M D

2014-12-01

To analyse satisfaction and patient preferences on the location where they receive an intravitreal injection. A survey was conducted with the intention of analysing these patients who attended the macula clinic and have been intervened using an intravitreal injection at least once in the day hospital or in the theatre setting, comparing both locations. The majority of the interviewed patients preferred the day hospital (50.0 versus 37.5%), mostly because of the comfort and the quick service. In patients with severe age-related macular degeneration (AMD) the option is reversed. The overall satisfaction level was positive in both cases (with 87.5% of patients satisfied or very satisfied in the day hospital and 91.1% in the theatre setting). Through the analysis of different aspects of clinical care the assessment was the same or superior for 75.0% of these patients, except in the waiting time. There were no cases of endophthalmitis. In general, patients prefer the clinical intervention in the consulting room than in the theatre setting because of the quicker service. There are several characteristics that can influence this choice and should be taken into account. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

Comparison of grid laser, intravitreal triamcinolone, and intravitreal bevacizumab in the treatment of diffuse diabetic macular edema.

PubMed

Sobaci, Güngör; Ozge, Gökhan; Erdurman, Cüneyt; Durukan, Hakan A; Bayraktar, Zeki M

2012-01-01

To compare the effects of grid laser (GL), intravitreal bevacizumab (IVB), and intravitreal triamcinolone acetonide (IVTA) in diffuse diabetic macular edema (DDME). One hundred and twenty-six patients (126 eyes) treated with GL (modified grid), IVTA (4 mg), and IVB (1.25 mg) injections, matched for best corrected visual acuity (BCVA) and OCT-based central macular thickness at presentation, were enrolled. Primary outcome measure was change in best corrected logMAR visual acuity at 1-year follow-up. Rates of visual stabilization (within ±0.2 logMAR of baseline BCVA) (71.4, 83.3, 78.6%, respectively) were not different between the groups (p = 0.41) at 12-month follow-up. Higher rates of anatomical and functional success, however, were evident in IVB and IVTA groups within 6 months of treatment (p < 0.05 for both). No severe adverse effects except higher intraocular pressure (10 mm Hg from baseline) in one third (14 eyes) of the IVTA cases, who required trabeculectomy in 2 (4.8%) eyes, were observed. Intraocular injections may give favorable results within the first 6 months, and after 6 months, GL results seem to be more favorable in the treatment of treatment-naïve, acute, nonischemic, and center-involving DDME. Copyright © 2011 S. Karger AG, Basel.

Intravitreal injection therapy in the treatment of noninfectious uveitis.

PubMed

Modorati, Giulio; Miserocchi, Elisabetta

2012-01-01

Uveitis is responsible for 5-20% of legal blindness in the United States and in Europe. In noninfectious uveitis, the most frequent uveitic complication that endangers sight is cystoid macular edema. Clinical characteristics, inflammation grading and visual acuity determine the choice of the correct therapy for each patient. We can utilize drugs either alone or in combination using different dosages and routes of administration. Intravitreal injection directly into the vitreous cavity leads to rapid therapeutic drug concentration in the retinal tissue and reduces systemic side effects. Intravitreally injected triamcinolone acetonide is the most powerful drug for the treatment of cystoid macular edema related to intraocular inflammation, but it also causes the most frequent and serious side effects. Due to the numerous side effects associated with the use of corticosteroids, there is a need to identify other anti-inflammatory agents with a better safety profile. Recent studies have demonstrated that intravitreal immunosuppressant injections of methotrexate or anti-VEGF agents may lead to fewer intraocular side effects, but also have a lower therapeutic activity for the reduction of macular edema. At present, intraocular anti-TNF-α drugs do not show promising results. As regards nonsteroidal anti-inflammatory drugs, further data are necessary to fully understand their efficacy and potential side effects. Copyright © 2012 S. Karger AG, Basel.

Submacular hemorrhage in neovascular age-related macular degeneration: A synthesis of the literature.

PubMed

Stanescu-Segall, Dinu; Balta, Florian; Jackson, Timothy L

2016-01-01

Large submacular hemorrhage, an uncommon manifestation of neovascular age-related macular degeneration, may also occur with idiopathic polypoidal choroidal vasculopathy. Submacular hemorrhage damages photoreceptors owing to iron toxicity, fibrin meshwork contraction, and reduced nutrient flux, with subsequent macular scarring. Clinical and experimental studies support prompt treatment, as tissue damage can occur within 24 hours. Without treatment the natural history is poor, with a mean final visual acuity (VA) of 20/1600. Reported treatments include retinal pigment epithelial patch, macular translocation, pneumatic displacement, intravitreal or subretinal tissue plasminogen activator, intravitreal anti-vascular endothelial growth factor (VEGF) drugs, and combinations thereof. In the absence of comparative studies, we combined eligible studies to assess the VA change before and after each treatment option. The greatest improvement occurred after combined pars plana vitrectomy, subretinal tissue plasminogen activator, intravitreal gas, and anti-vascular endothelial growth factor treatment, with VA improving from 20/1000 to 20/400. The best final VA occurred using combined intravitreal tissue plasminogen activator, gas, and anti-vascular endothelial growth factor therapy, with VA improving from 20/200 to 20/100. Both treatments had an acceptable safety profile, but most studies were small, and larger randomized controlled trials are needed to determine both safety and efficacy. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

SILAC proteomics of planarians identifies Ncoa5 as a conserved component of pluripotent stem cells.

PubMed

Böser, Alexander; Drexler, Hannes C A; Reuter, Hanna; Schmitz, Henning; Wu, Guangming; Schöler, Hans R; Gentile, Luca; Bartscherer, Kerstin

2013-11-27

Planarian regeneration depends on the presence of pluripotent stem cells in the adult. We developed an in vivo stable isotope labeling by amino acids in cell culture (SILAC) protocol in planarians to identify proteins that are enriched in planarian stem cells. Through a comparison of SILAC proteomes of normal and stem cell-depleted planarians and of a stem cell-enriched population of sorted cells, we identified hundreds of stem cell proteins. One of these is an ortholog of nuclear receptor coactivator-5 (Ncoa5/CIA), which is known to regulate estrogen-receptor-mediated transcription in human cells. We show that Ncoa5 is essential for the maintenance of the pluripotent stem cell population in planarians and that a putative mouse ortholog is expressed in pluripotent cells of the embryo. Our study thus identifies a conserved component of pluripotent stem cells, demonstrating that planarians, in particular, when combined with in vivo SILAC, are a powerful model in stem cell research. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

Effects of muscarinic antagonists on ZENK expression in the chicken retina.

PubMed

Bitzer, Michaela; Kovacs, Beatrix; Feldkaemper, Marita; Schaeffel, Frank

2006-03-01

Muscarinic antagonists, particularly atropine, can inhibit myopia development in several animal models and also in children. However, the biochemical basis of the inhibition of axial eye growth remains obscure, and there are doubts whether muscarinic receptors are involved at all. Experiments in chickens and monkeys have shown that the synthesis of the transcription factor ZENK, also named Egr-1, in retinal glucagon amacrine cells is strongly associated with inhibition of axial eye growth (assumed to create a STOP signal). We have tested whether the muscarinic antagonists atropine, pirenzepine, oxyphenonium, gallamine, MT-3, himbacine, and 4-DAMP can stimulate ZENK expression so that the drugs' inhibitory effect on myopia development could be explained by an enhanced STOP signal. Because it is known that intravitreal quisqualic acid (QA) eliminates most cholinergic neurons in the retina within 6 or 7 days, in a second set of experiments, we tested whether these antagonists could still stimulate ZENK production, 6 days after QA was applied. Muscarinic antagonists, injected intravitreally at various concentrations, affected ZENK synthesis in various and unpredictable ways. Pirenzepine, oxyphenonium, and MT-3 increased the proportion of glucagon cells that were ZENK-immunoreactive, whereas himbacine decreased that proportion, and gallamine and 4-DAMP had no significant effect. Atropine caused an upregulation of ZENK only if all positive amacrine and bipolar cells were counted and therefore appeared to affect primarily cells other than glucagon amacrines. The pattern of results remained unchanged after ablation of most cholinergic neurons by QA. Our results suggest that at least some muscarinic antagonists do not activate cells that synthesize ZENK when they inhibit axial eye growth. Therefore, in line with other studies they also cast doubt on the assumption that muscarinic transmission is crucial, and they suggest that muscarinic antagonists may inhibit myopia through extraretinal target sites or through non-cholinergic retinal actions.

[An in vivo study of basic fibroblast growth factor on activation and proliferation of retinal progenitor cell in RCS rats].

PubMed

Xia, Xiaoping; Song, Guoxiang; Liu, Xiangfu; Tang, Xiangchen; Ye, Hui

2010-11-01

To investigate the effect of intravitreal basic fibroblast growth factor(bFGF) on activation and proliferation of endogenous retinal progenitor cells in the Royal College of Surgeons(RCS) rats. Twenty-four rats were studied after the 30th postnatal day(≥30). Eighteen affected rats were randomly divided into 3 groups: bFGF-treated, vehicle-treated and untreated group, and 6 unaffected rats were used as normal controls. Six μl of bFGF (5μg/10 μl) or vehicle was injected into the vitreous on days 31, 33 and 35 after birth (P31, P33, P35) in the bFGF group and vehicle group, and no injection was administered in the untreated and control groups. All the rats were euthanized, and their eyes were enucleated, hemisected and fixed at 50 d after birth for immunohistochemistry and measurement of outer nuclear layer thickness. Nestin and Chx10 were positively expressed in all retinal layers, intravitreous injection of bFGF in retina-dystrophic RCS(RCS-p+/Lav) rats induced intense labeling for the retinal progenitor cell markers Chx10 and Nestin, which were highly colocalized. Fluorescence intensity for both labels was slightly less in the control rats, and much less in the vehicle-injected rats as well as in the untreated RCS rats. The outer nuclear layer (ONL) was significantly thicker in bFGF group than that of vehicle-treated or untreated group(p<0.01), but thinner than that of the control group(p<0.01). No significant difference was observed in the ONL thicknesses between the vehicle group and untreated group(P>0.05). bFGF may contribute to the activation of retinal progenitor cells in RCS rats, thus counteract degeneration by promoting the proliferation of the progenitor cells.

Stem cells in reproductive medicine: ready for the patient?

PubMed

Vassena, R; Eguizabal, C; Heindryckx, B; Sermon, K; Simon, C; van Pelt, A M M; Veiga, A; Zambelli, F

2015-09-01

Are there effective and clinically validated stem cell-based therapies for reproductive diseases? At the moment, clinically validated stem cell treatments for reproductive diseases and alterations are not available. Research in stem cells and regenerative medicine is growing in scope, and its translation to the clinic is heralded by the recent initiation of controlled clinical trials with pluripotent derived cells. Unfortunately, stem cell 'treatments' are currently offered to patients outside of the controlled framework of scientifically sound research and regulated clinical trials. Both physicians and patients in reproductive medicine are often unsure about stem cells therapeutic options. An international working group was assembled to review critically the available scientific literature in both the human species and animal models. This review includes work published in English until December 2014, and available through Pubmed. A few areas of research in stem cell and reproductive medicine were identified: in vitro gamete production, endometrial regeneration, erectile dysfunction amelioration, vaginal reconstruction. The stem cells studied range from pluripotent (embryonic stem cells and induced pluripotent stem cells) to monopotent stem cells, such as spermatogonial stem cells or mesenchymal stem cells. The vast majority of studies have been carried out in animal models, with data that are preliminary at best. This review was not conducted in a systematic fashion, and reports in publications not indexed in Pubmed were not analyzed. A much broader clinical knowledge will have to be acquired before translation to the clinic of stem cell therapies in reproductive medicine; patients and physicians should be wary of unfounded claims of improvement of existing medical conditions; at the moment, effective stem cell treatment for reproductive diseases and alterations is not available. None. NA. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

I.V. infusion of brain-derived neurotrophic factor gene-modified human mesenchymal stem cells protects against injury in a cerebral ischemia model in adult rat.

PubMed

Nomura, T; Honmou, O; Harada, K; Houkin, K; Hamada, H; Kocsis, J D

2005-01-01

I.V. delivery of mesenchymal stem cells prepared from adult bone marrow reduces infarction size and ameliorates functional deficits in rat cerebral ischemia models. Administration of the brain-derived neurotrophic factor to the infarction site has also been demonstrated to be neuroprotective. To test the hypothesis that brain-derived neurotrophic factor contributes to the therapeutic benefits of mesenchymal stem cell delivery, we compared the efficacy of systemic delivery of human mesenchymal stem cells and human mesenchymal stem cells transfected with a fiber-mutant F/RGD adenovirus vector with a brain-derived neurotrophic factor gene (brain-derived neurotrophic factor-human mesenchymal stem cells). A permanent middle cerebral artery occlusion was induced by intraluminal vascular occlusion with a microfilament. Human mesenchymal stem cells and brain-derived neurotrophic factor-human mesenchymal stem cells were i.v. injected into the rats 6 h after middle cerebral artery occlusion. Lesion size was assessed at 6 h, 1, 3 and 7 days using MR imaging, and histological methods. Functional outcome was assessed using the treadmill stress test. Both human mesenchymal stem cells and brain-derived neurotrophic factor-human mesenchymal stem cells reduced lesion volume and elicited functional improvement compared with the control sham group, but the effect was greater in the brain-derived neurotrophic factor-human mesenchymal stem cell group. ELISA analysis of the infarcted hemisphere revealed an increase in brain-derived neurotrophic factor in the human mesenchymal stem cell groups, but a greater increase in the brain-derived neurotrophic factor-human mesenchymal stem cell group. These data support the hypothesis that brain-derived neurotrophic factor contributes to neuroprotection in cerebral ischemia and cellular delivery of brain-derived neurotrophic factor can be achieved by i.v. delivery of human mesenchymal stem cells.

Distinct roles of neuroepithelial-like and radial glia-like progenitor cells in cerebellar regeneration.

PubMed

Kaslin, Jan; Kroehne, Volker; Ganz, Julia; Hans, Stefan; Brand, Michael

2017-04-15

Zebrafish can regenerate after brain injury, and the regenerative process is driven by resident stem cells. Stem cells are heterogeneous in the vertebrate brain, but the significance of having heterogeneous stem cells in regeneration is not understood. Limited availability of specific stem cells might impair the regeneration of particular cell lineages. We studied regeneration of the adult zebrafish cerebellum, which contains two major stem and progenitor cell types: ventricular zone and neuroepithelial cells. Using conditional lineage tracing we demonstrate that cerebellar regeneration depends on the availability of specific stem cells. Radial glia-like cells are thought to be the predominant stem cell type in homeostasis and after injury. However, we find that radial glia-like cells play a minor role in adult cerebellar neurogenesis and in recovery after injury. Instead, we find that neuroepithelial cells are the predominant stem cell type supporting cerebellar regeneration after injury. Zebrafish are able to regenerate many, but not all, cell types in the cerebellum, which emphasizes the need to understand the contribution of different adult neural stem and progenitor cell subtypes in the vertebrate central nervous system. © 2017. Published by The Company of Biologists Ltd.

Role of the Stem Cell Niche in Hormone-induced Tumorigenesis in Fetal Mouse Mammary Epithelium

DTIC Science & Technology

2006-08-01

Develop an immunohistochemical method for identifying stem cells and stem cell niches, and to use this to determine if in utero estrogenic...overstimulation causes changes in the number of stem cells or their niches. To extend the power of ex vivo stem cell isolation and enumeration by providing a...marginal success due primarily to 1) most antibodies previously reputed to be stem cell specific turned out to be present in differentiated mammary

Wnt and BMP Signaling Crosstalk in Regulating Dental Stem Cells: Implications in Dental Tissue Engineering

PubMed Central

Zhang, Fugui; Song, Jinglin; Zhang, Hongmei; Huang, Enyi; Song, Dongzhe; Tollemar, Viktor; Wang, Jing; Wang, Jinhua; Mohammed, Maryam; Wei, Qiang; Fan, Jiaming; Liao, Junyi; Zou, Yulong; Liu, Feng; Hu, Xue; Qu, Xiangyang; Chen, Liqun; Yu, Xinyi; Luu, Hue H.; Lee, Michael J.; He, Tong-Chuan; Ji, Ping

2016-01-01

Tooth is a complex hard tissue organ and consists of multiple cell types that are regulated by important signaling pathways such as Wnt and BMP signaling. Serious injuries and/or loss of tooth or periodontal tissues may significantly impact aesthetic appearance, essential oral functions and the quality of life. Regenerative dentistry holds great promise in treating oral/dental disorders. The past decade has witnessed a rapid expansion of our understanding of the biological features of dental stem cells, along with the signaling mechanisms governing stem cell self-renewal and differentiation. In this review, we first summarize the biological characteristics of seven types of dental stem cells, including dental pulp stem cells, stem cells from apical papilla, stem cells from human exfoliated deciduous teeth, dental follicle precursor cells, periodontal ligament stem cells, alveolar bone-derived mesenchymal stem cells (MSCs), and MSCs from gingiva. We then focus on how these stem cells are regulated by bone morphogenetic protein (BMP) and/or Wnt signaling by examining the interplays between these pathways. Lastly, we analyze the current status of dental tissue engineering strategies that utilize oral/dental stem cells by harnessing the interplays between BMP and Wnt pathways. We also highlight the challenges that must be addressed before the dental stem cells may reach any clinical applications. Thus, we can expect to witness significant progresses to be made in regenerative dentistry in the coming decade. PMID:28491933

Extracellular Matrix as a Regulator of Epidermal Stem Cell Fate.

PubMed

Chermnykh, Elina; Kalabusheva, Ekaterina; Vorotelyak, Ekaterina

2018-03-27

Epidermal stem cells reside within the specific anatomic location, called niche, which is a microenvironment that interacts with stem cells to regulate their fate. Regulation of many important processes, including maintenance of stem cell quiescence, self-renewal, and homeostasis, as well as the regulation of division and differentiation, are common functions of the stem cell niche. As it was shown in multiple studies, extracellular matrix (ECM) contributes a lot to stem cell niches in various tissues, including that of skin. In epidermis, ECM is represented, primarily, by a highly specialized ECM structure, basement membrane (BM), which separates the epidermal and dermal compartments. Epidermal stem cells contact with BM, but when they lose the contact and migrate to the overlying layers, they undergo terminal differentiation. When considering all of these factors, ECM is of fundamental importance in regulating epidermal stem cells maintenance, proper mobilization, and differentiation. Here, we summarize the remarkable progress that has recently been made in the research of ECM role in regulating epidermal stem cell fate, paying special attention to the hair follicle stem cell niche. We show that the destruction of ECM components impairs epidermal stem cell morphogenesis and homeostasis. A deep understanding of ECM molecular structure as well as the development of in vitro system for stem cell maintaining by ECM proteins may bring us to developing new approaches for regenerative medicine.

Knowledge and Attitude about Stem Cells and Their Application in Medicine among Nursing Students in Universiti Sains Malaysia, Malaysia

PubMed Central

LYE, Jee Leng; SOON, Lean Keng; WAN AHMAD, Wan Amir Nizam; TAN, Suat Cheng

2015-01-01

Background: Stem cell research has been extensively explored worldwide to enhance human health in medical setting. Nevertheless, there is currently no full understanding of the stem cell knowledge and attitude levels among student nurses in Malaysia. This study aimed to assess the level of stem cell knowledge, attitude toward stem cell application in medicine, and its association with years of education, among Universiti Sains Malaysia (USM) undergraduate nursing students. Methods: A cross-sectional study (n = 88) was conducted using self-administered questionnaire consisted of demographic information, stem cells knowledge and attitude statements. Data was analysed using Statistical Package Social Software 20.0. Results: The majority of participants (92%) had moderate knowledge score about stem cells. Many students (33%) worried that stem cell application might cause a harm to humanity yet had a positive (76.1%) attitude towards its therapeutic potential (45.5%). Poor correlation between knowledge and attitude (r = 0.08) indicated that acceptance towards stem cell is not solely based on the knowledge level but also on other factors including religion and culture. Conclusion: Therefore, this study suggests that various educational programs on stem cell should be implemented considering the religion, cultural, social, and behavioural determinants in the population to improve stem cell knowledge and encourage a more positive attitude towards stem cells in medicine among these nursing students. PMID:26715905

Knowledge and Attitude about Stem Cells and Their Application in Medicine among Nursing Students in Universiti Sains Malaysia, Malaysia.

PubMed

Lye, Jee Leng; Soon, Lean Keng; Wan Ahmad, Wan Amir Nizam; Tan, Suat Cheng

2015-01-01

Stem cell research has been extensively explored worldwide to enhance human health in medical setting. Nevertheless, there is currently no full understanding of the stem cell knowledge and attitude levels among student nurses in Malaysia. This study aimed to assess the level of stem cell knowledge, attitude toward stem cell application in medicine, and its association with years of education, among Universiti Sains Malaysia (USM) undergraduate nursing students. A cross-sectional study (n = 88) was conducted using self-administered questionnaire consisted of demographic information, stem cells knowledge and attitude statements. Data was analysed using Statistical Package Social Software 20.0. The majority of participants (92%) had moderate knowledge score about stem cells. Many students (33%) worried that stem cell application might cause a harm to humanity yet had a positive (76.1%) attitude towards its therapeutic potential (45.5%). Poor correlation between knowledge and attitude (r = 0.08) indicated that acceptance towards stem cell is not solely based on the knowledge level but also on other factors including religion and culture. Therefore, this study suggests that various educational programs on stem cell should be implemented considering the religion, cultural, social, and behavioural determinants in the population to improve stem cell knowledge and encourage a more positive attitude towards stem cells in medicine among these nursing students.

Stem cell motility enables a density-dependent rate of fate commitment during scaled resizing of adult organs

NASA Astrophysics Data System (ADS)

Du, Xinxin; O'Brien, Lucy; Riedel-Kruse, Ingmar

Many adult organs grow or shrink to accommodate fluctuating levels of physiological demand. Specifically, the intestine of the fruit fly (the midgut) expands four-fold in the number of mature cells and, proportionally, the number of stem cells when the fly eats. However, the cellular behaviors that give rise to this stem scaling are not well-understood. Here we present a biophysical model of the adult fly midgut. A set of differential equations can recapitulate the physiological kinetics of cells during midgut growth and shrinkage as long as the rate of stem cell fate commitment depends on the stem cell number density in the tissue. To elucidate the source of this dependence, we model the tissue in a 2D simulation with soft spheres, where stem cells choose fate commitment through Delta-Notch pathway interactions with other stem cells, a known process in fly midguts. We find that as long as stem cells exhibit a large enough amplitude of random motion through the tissue (`stem cell motility'), and explore a large enough `territory' in their lifetime, stem cell scaling can occur. These model observations are confirmed through in vivo live-imaging, where we indeed see that stem cells are motile in the fly midgut.

Ethics and Policy Issues for Stem Cell Research and Pulmonary Medicine

PubMed Central

Lowenthal, Justin

2015-01-01

Stem cell research and related initiatives in regenerative medicine, cell-based therapy, and tissue engineering have generated considerable scientific and public interest. Researchers are applying stem cell technologies to chest medicine in a variety of ways: using stem cells as models for drug discovery, testing stem cell-based therapies for conditions as diverse as COPD and cystic fibrosis, and producing functional lung and tracheal tissue for physiologic modeling and potential transplantation. Although significant scientific obstacles remain, it is likely that stem cell-based regenerative medicine will have a significant clinical impact in chest medicine. However, stem cell research has also generated substantial controversy, posing a variety of ethical and regulatory challenges for research and clinical practice. Some of the most prominent ethical questions related to the use of stem cell technologies in chest medicine include (1) implications for donors, (2) scientific prerequisites for clinical testing and use, (3) stem cell tourism, (4) innovation and clinical use of emerging stem cell-based interventions, (5) responsible translation of stem cell-based therapies to clinical use, and (6) appropriate and equitable access to emerging therapies. Having a sense of these issues should help to put emerging scientific advances into appropriate context and to ensure the responsible clinical translation of promising therapeutics. PMID:25732448

A Survey of Italian Physicians' Opinion about Stem Cells Research: What Doctors Prefer and What the Law Requires

PubMed Central

Frati, Paola; Pacchiarotti, Arianna; D'Errico, Stefano

2014-01-01

To evaluate the Italian physicians' knowledge/information level about the therapeutic potential of stem cells, the research choice between embryonic and cordonal stem cells, and the preference between autologous and heterologous storage of cordonal stem cells, we performed a national survey. The questionnaire—distributed to 3361 physicians—involved physicians of different religious orientations and of different medical specialities. Most of the physicians involved (67%) were Catholics, and the majority were gynaecologists and paediatricians (43%) who are mainly in charge to inform future mothers about the possibility of cordonal stem cells conservation. The majority of the physicians interviewed do not have specific knowledge about stem cells (59%), most of them having only generic information (92%). The largest part of physicians prefer to use umbilical cord blood cells rather than embryonic stem cells. Nevertheless, a large percentage of physicians were in favour of embryo research, especially when embryos are supernumerary (44% versus 34%). Eighty-seven % of the physicians interviewed proved to have a general knowledge about stem cells and believe in their therapeutic potential. They prefer research on cordonal stem cells rather than on embryo stem cells. Although they are in favour of heterologous stem cells donation, they still prefer cryopreservation for personal use. PMID:24877099

Ethics and policy issues for stem cell research and pulmonary medicine.

PubMed

Lowenthal, Justin; Sugarman, Jeremy

2015-03-01

Stem cell research and related initiatives in regenerative medicine, cell-based therapy, and tissue engineering have generated considerable scientific and public interest. Researchers are applying stem cell technologies to chest medicine in a variety of ways: using stem cells as models for drug discovery, testing stem cell-based therapies for conditions as diverse as COPD and cystic fibrosis, and producing functional lung and tracheal tissue for physiologic modeling and potential transplantation. Although significant scientific obstacles remain, it is likely that stem cell-based regenerative medicine will have a significant clinical impact in chest medicine. However, stem cell research has also generated substantial controversy, posing a variety of ethical and regulatory challenges for research and clinical practice. Some of the most prominent ethical questions related to the use of stem cell technologies in chest medicine include (1) implications for donors, (2) scientific prerequisites for clinical testing and use, (3) stem cell tourism, (4) innovation and clinical use of emerging stem cell-based interventions, (5) responsible translation of stem cell-based therapies to clinical use, and (6) appropriate and equitable access to emerging therapies. Having a sense of these issues should help to put emerging scientific advances into appropriate context and to ensure the responsible clinical translation of promising therapeutics.

Propagation of human spermatogonial stem cells in vitro.

PubMed

Sadri-Ardekani, Hooman; Mizrak, Sefika C; van Daalen, Saskia K M; Korver, Cindy M; Roepers-Gajadien, Hermien L; Koruji, Morteza; Hovingh, Suzanne; de Reijke, Theo M; de la Rosette, Jean J M C H; van der Veen, Fulco; de Rooij, Dirk G; Repping, Sjoerd; van Pelt, Ans M M

2009-11-18

Young boys treated with high-dose chemotherapy are often confronted with infertility once they reach adulthood. Cryopreserving testicular tissue before chemotherapy and autotransplantation of spermatogonial stem cells at a later stage could theoretically allow for restoration of fertility. To establish in vitro propagation of human spermatogonial stem cells from small testicular biopsies to obtain an adequate number of cells for successful transplantation. Study performed from April 2007 to July 2009 using testis material donated by 6 adult men who underwent orchidectomy as part of prostate cancer treatment. Testicular cells were isolated and cultured in supplemented StemPro medium; germline stem cell clusters that arose were subcultured on human placental laminin-coated dishes in the same medium. Presence of spermatogonia was determined by reverse transcriptase polymerase chain reaction and immunofluorescence for spermatogonial markers. To test for the presence of functional spermatogonial stem cells in culture, xenotransplantation to testes of immunodeficient mice was performed, and migrated human spermatogonial stem cells after transplantation were detected by COT-1 fluorescence in situ hybridization. The number of colonized spermatogonial stem cells transplanted at early and later points during culture were counted to determine propagation. Propagation of spermatogonial stem cells over time. Testicular cells could be cultured and propagated up to 15 weeks. Germline stem cell clusters arose in the testicular cell cultures from all 6 men and could be subcultured and propagated up to 28 weeks. Expression of spermatogonial markers on both the RNA and protein level was maintained throughout the entire culture period. In 4 of 6 men, xenotransplantation to mice demonstrated the presence of functional spermatogonial stem cells, even after prolonged in vitro culture. Spermatogonial stem cell numbers increased 53-fold within 19 days in the testicular cell culture and increased 18,450-fold within 64 days in the germline stem cell subculture. Long-term culture and propagation of human spermatogonial stem cells in vitro is achievable.

Stem cell technology for drug discovery and development.

PubMed

Hook, Lilian A

2012-04-01

Stem cells have enormous potential to revolutionise the drug discovery process at all stages, from target identification through to toxicology studies. Their ability to generate physiologically relevant cells in limitless supply makes them an attractive alternative to currently used recombinant cell lines or primary cells. However, realisation of the full potential of stem cells is currently hampered by the difficulty in routinely directing stem cell differentiation to reproducibly and cost effectively generate pure populations of specific cell types. In this article we discuss how stem cells have already been used in the drug discovery process and how novel technologies, particularly in relation to stem cell differentiation, can be applied to attain widespread adoption of stem cell technology by the pharmaceutical industry. Copyright © 2011 Elsevier Ltd. All rights reserved.

College Students' Conceptions of Stem Cells, Stem Cell Research, and Cloning

NASA Astrophysics Data System (ADS)

Concannon, James P.; Siegel, Marcelle A.; Halverson, Kristy; Freyermuth, Sharyn

2010-04-01

In this study, we examined 96 undergraduate non-science majors' conceptions of stem cells, stem cell research, and cloning. This study was performed at a large, Midwest, research extensive university. Participants in the study were asked to answer 23 questions relating to stem cells, stem cell research, and cloning in an on-line assessment before and after instruction. Two goals of the instruction were to: (1) help students construct accurate scientific ideas, and (2) enhance their reasoning about socioscientific issues. The course structure included interactive lectures, case discussions, hands-on activities, and independent projects. Overall, students' understandings of stem cells, stem cell research, and cloning increased from pre-test to post-test. For example, on the post-test, students gained knowledge concerning the age of an organism related to the type of stem cell it possesses. However, we found that some incorrect ideas that were evident on the pre-test persisted after instruction. For example, before and after instruction several students maintained the idea that stem cells can currently be used to produce organs.

Advances and Prospects in Stem Cells for Cartilage Regeneration

PubMed Central

Wang, Mingjie; Yuan, Zhiguo; Ma, Ning; Hao, Chunxiang; Guo, Weimin; Zou, Gengyi; Zhang, Yu; Chen, Mingxue; Gao, Shuang; Wang, Aiyuan; Wang, Yu; Sui, Xiang; Xu, Wenjing; Lu, Shibi

2017-01-01

The histological features of cartilage call attention to the fact that cartilage has a little capacity to repair itself owing to the lack of a blood supply, nerves, or lymphangion. Stem cells have emerged as a promising option in the field of cartilage tissue engineering and regenerative medicine and could lead to cartilage repair. Much research has examined cartilage regeneration utilizing stem cells. However, both the potential and the limitations of this procedure remain controversial. This review presents a summary of emerging trends with regard to using stem cells in cartilage tissue engineering and regenerative medicine. In particular, it focuses on the characterization of cartilage stem cells, the chondrogenic differentiation of stem cells, and the various strategies and approaches involving stem cells that have been used in cartilage repair and clinical studies. Based on the research into chondrocyte and stem cell technologies, this review discusses the damage and repair of cartilage and the clinical application of stem cells, with a view to increasing our systematic understanding of the application of stem cells in cartilage regeneration; additionally, several advanced strategies for cartilage repair are discussed. PMID:28246531

Stem Cell-Derived Exosome in Cardiovascular Diseases: Macro Roles of Micro Particles.

PubMed

Yuan, Ye; Du, Weijie; Liu, Jiaqi; Ma, Wenya; Zhang, Lai; Du, Zhimin; Cai, Benzhi

2018-01-01

The stem cell-based therapy has emerged as the promising therapeutic strategies for cardiovascular diseases (CVDs). Recently, increasing evidence suggest stem cell-derived active exosomes are important communicators among cells in the heart via delivering specific substances to the adjacent/distant target cells. These exosomes and their contents such as certain proteins, miRNAs and lncRNAs exhibit huge beneficial effects on preventing heart damage and promoting cardiac repair. More importantly, stem cell-derived exosomes are more effective and safer than stem cell transplantation. Therefore, administration of stem cell-derived exosomes will expectantly be an alternative stem cell-based therapy for the treatment of CVDs. Furthermore, modification of stem cell-derived exosomes or artificial synthesis of exosomes will be the new therapeutic tools for CVDs in the future. In addition, stem cell-derived exosomes also have been implicated in the diagnosis and prognosis of CVDs. In this review, we summarize the current advances of stem cell-derived exosome-based treatment and prognosis for CVDs, including their potential benefits, underlying mechanisms and limitations, which will provide novel insights of exosomes as a new tool in clinical therapeutic translation in the future.

Stem cells and reproduction.

PubMed

Du, Hongling; Taylor, Hugh S

2010-06-01

To review the latest developments in reproductive tract stem cell biology. In 2004, two studies indicated that ovaries contain stem cells which form oocytes in adults and that can be cultured in vitro into mature oocytes. A live birth after orthotopic transplantation of cryopreserved ovarian tissue in a woman whose ovaries were damaged by chemotherapy demonstrates the clinical potential of these cells. In the same year, another study provided novel evidence of endometrial regeneration by stem cells in women who received bone marrow transplants. This finding has potential for the use in treatment of uterine disorders. It also supports a new theory for the cause of endometriosis, which may have its origin in ectopic transdifferentiation of stem cells. Several recent studies have demonstrated that fetal cells enter the maternal circulation and generate microchimerism in the mother. The uterus is a dynamic organ permeable to fetal stem cells, capable of transdifferentiation and an end organ in which bone marrow stem cells may differentiate. Finally stem cell transformation can be an underlying cause of ovarian cancer. Whereas we are just beginning to understand stem cells, the potential implications of stem cells to reproductive biology and medicine are apparent.

Biliary tract cancer stem cells - translational options and challenges

PubMed Central

Mayr, Christian; Ocker, Matthias; Ritter, Markus; Pichler, Martin; Neureiter, Daniel; Kiesslich, Tobias

2017-01-01

Management of biliary tract cancer remains challenging. Tumors show high recurrence rates and therapeutic resistance, leading to dismal prognosis and short survival. The cancer stem cell model states that a tumor is a heterogeneous conglomerate of cells, in which a certain subpopulation of cells - the cancer stem cells - possesses stem cell properties. Cancer stem cells have high clinical relevance due to their potential contributions to development, progression and aggressiveness as well as recurrence and metastasis of malignant tumors. Consequently, reliable identification of as well as pharmacological intervention with cancer stem cells is an intensively investigated and promising research field. The involvement of cancer stem cells in biliary tract cancer is likely as a number of studies demonstrated their existence and the obvious clinical relevance of several established cancer stem cell markers in biliary tract cancer models and tissues. In the present article, we review and discuss the currently available literature addressing the role of putative cancer stem cells in biliary tract cancer as well as the connection between known contributors of biliary tract tumorigenesis such as oncogenic signaling pathways, micro-RNAs and the tumor microenvironment with cancer stem cells. PMID:28465631

Ultraviolet Radiation-Induced Skin Aging: The Role of DNA Damage and Oxidative Stress in Epidermal Stem Cell Damage Mediated Skin Aging

PubMed Central

Panich, Uraiwan; Sittithumcharee, Gunya; Rathviboon, Natwarath

2016-01-01

Skin is the largest human organ. Skin continually reconstructs itself to ensure its viability, integrity, and ability to provide protection for the body. Some areas of skin are continuously exposed to a variety of environmental stressors that can inflict direct and indirect damage to skin cell DNA. Skin homeostasis is maintained by mesenchymal stem cells in inner layer dermis and epidermal stem cells (ESCs) in the outer layer epidermis. Reduction of skin stem cell number and function has been linked to impaired skin homeostasis (e.g., skin premature aging and skin cancers). Skin stem cells, with self-renewal capability and multipotency, are frequently affected by environment. Ultraviolet radiation (UVR), a major cause of stem cell DNA damage, can contribute to depletion of stem cells (ESCs and mesenchymal stem cells) and damage of stem cell niche, eventually leading to photoinduced skin aging. In this review, we discuss the role of UV-induced DNA damage and oxidative stress in the skin stem cell aging in order to gain insights into the pathogenesis and develop a way to reduce photoaging of skin cells. PMID:27148370

Identification of Metastatic Tumor Stem Cell

DTIC Science & Technology

2010-09-01

addition to a tumor stem cell , an existence of a metastatic stem cell is predicted. Despite the critical importance of the concept, this idea has not been...isolating stem cell population from a unique set of breast tumor cell lines and by examining their metastatic behavior in an animal model. The overall...will (i) isolate stem - cell population from non-metastatic and metastatic cells of a pair of syngenic breast tumor cell lines, and test their metastatic

Roles of neural stem cells in the repair of peripheral nerve injury.

PubMed

Wang, Chong; Lu, Chang-Feng; Peng, Jiang; Hu, Cheng-Dong; Wang, Yu

2017-12-01

Currently, researchers are using neural stem cell transplantation to promote regeneration after peripheral nerve injury, as neural stem cells play an important role in peripheral nerve injury repair. This article reviews recent research progress of the role of neural stem cells in the repair of peripheral nerve injury. Neural stem cells can not only differentiate into neurons, astrocytes and oligodendrocytes, but can also differentiate into Schwann-like cells, which promote neurite outgrowth around the injury. Transplanted neural stem cells can differentiate into motor neurons that innervate muscles and promote the recovery of neurological function. To promote the repair of peripheral nerve injury, neural stem cells secrete various neurotrophic factors, including brain-derived neurotrophic factor, fibroblast growth factor, nerve growth factor, insulin-like growth factor and hepatocyte growth factor. In addition, neural stem cells also promote regeneration of the axonal myelin sheath, angiogenesis, and immune regulation. It can be concluded that neural stem cells promote the repair of peripheral nerve injury through a variety of ways.

Day-night cycles and the sleep-promoting factor, Sleepless, affect stem cell activity in the Drosophila testis.

PubMed

Tulina, Natalia M; Chen, Wen-Feng; Chen, Jung Hsuan; Sowcik, Mallory; Sehgal, Amita

2014-02-25

Adult stem cells maintain tissue integrity and function by renewing cellular content of the organism through regulated mitotic divisions. Previous studies showed that stem cell activity is affected by local, systemic, and environmental cues. Here, we explore a role of environmental day-night cycles in modulating cell cycle progression in populations of adult stem cells. Using a classic stem cell system, the Drosophila spermatogonial stem cell niche, we reveal daily rhythms in division frequencies of germ-line and somatic stem cells that act cooperatively to produce male gametes. We also examine whether behavioral sleep-wake cycles, which are driven by the environmental day-night cycles, regulate stem cell function. We find that flies lacking the sleep-promoting factor Sleepless, which maintains normal sleep in Drosophila, have increased germ-line stem cell (GSC) division rates, and this effect is mediated, in part, through a GABAergic signaling pathway. We suggest that alterations in sleep can influence the daily dynamics of GSC divisions.

IL-17B activated mesenchymal stem cells enhance proliferation and migration of gastric cancer cells.

PubMed

Bie, Qingli; Zhang, Bin; Sun, Caixia; Ji, Xiaoyun; Barnie, Prince Amoah; Qi, Chen; Peng, Jingjing; Zhang, Danyi; Zheng, Dong; Su, Zhaoliang; Wang, Shengjun; Xu, Huaxi

2017-03-21

Mesenchymal stem cells are important cells in tumor microenvironment. We have previously demonstrated that IL-17B/IL-17RB signal promoted progression of gastric cancer. In this study, we further explored the effect of IL-17B on mesenchymal stem cells in tumor microenvironment and its impact on the tumor progression. The results showed that IL-17B induced the expression of stemness-related genes Nanog, Sox2, and Oct4 in mesenchymal stem cells and enhanced its tumor-promoting effect. The supernatant from cultured mesenchymal stem cells after treating with exogenous rIL-17B promoted the proliferation and migration of MGC-803, therefor suggesting that rIL-17B might promote mesenchymal stem cells to produce soluble factors. In addition, rIL-17B also activated the NF-κΒ, STAT3, β-catenin pathway in mesenchymal stem cells. Our data revealed a new mechanism that IL-17B enhanced the progression of gastric cancer by activating mesenchymal stem cells.

A Phenotype-Based RNAi Screening for Ras-ERK/MAPK Signaling-Associated Stem Cell Regulators in C. elegans.

PubMed

Lee, Myon-Hee; Yoon, Dong Suk

2017-01-01

Stem cells have the ability to self-renew and to generate differentiated cell types. A regulatory network that controls this balance is critical for stem cell homeostasis and normal animal development. Particularly, Ras-ERK/MAPK signaling pathway is critical for stem cell self-renewal and differentiation in mammals, including humans. Aberrant regulation of Ras-ERK/MAPK signaling pathway results in either stem cell or overproliferation. Therefore, the identification of Ras-ERK/MAPK signaling pathway-associated regulators is critical to understand the mechanism of stem cell (possibly cancer stem cell) control. In this report, using the nematode C. elegans mutants, we developed a methodology for a phenotype-based RNAi screening that identifies stem cell regulator genes associated with Ras-ERK/MAPK signaling within the context of a whole organism. Importantly, this phenotype-based RNAi screening can be applied for other stem cell-associated signaling pathways such as Wnt/β-catenin and Notch using the C. elegans.

Retinitis pigmentosa-associated cystoid macular oedema: pathogenesis and avenues of intervention

PubMed Central

Strong, S; Liew, G; Michaelides, M

2017-01-01

Hereditary retinal diseases are now the leading cause of blindness certification in the working age population (age 16–64 years) in England and Wales, of which retinitis pigmentosa (RP) is the most common disorder. RP may be complicated by cystoid macular oedema (CMO), causing a reduction of central vision. The underlying pathogenesis of RP-associated CMO (RP-CMO) remains uncertain, however, several mechanisms have been proposed, including: (1) breakdown of the blood-retinal barrier, (2) failure (or dysfunction) of the pumping mechanism in the retinal pigment epithelial, (3) Müller cell oedema and dysfunction, (4) antiretinal antibodies and (5) vitreous traction. There are limited data on efficacy of treatments for RP-CMO. Treatments attempted to date include oral and topical carbonic anhydrase inhibitors, oral, topical, intravitreal and periocular steroids, topical non-steroidal anti-inflammatory medications, photocoagulation, vitrectomy with internal limiting membrane peel, oral lutein and intravitreal antivascular endothelial growth factor injections. This review summarises the evidence supporting these treatment modalities. Successful management of RP-CMO should aim to improve both quality and quantity of vision in the short term and may also slow central vision loss over time. PMID:27913439

Catalytic Nanoceria Are Preferentially Retained in the Rat Retina and Are Not Cytotoxic after Intravitreal Injection

PubMed Central

Wong, Lily L.; Hirst, Suzanne M.; Pye, Quentin N.; Reilly, Christopher M.; Seal, Sudipta; McGinnis, James F.

2013-01-01

Cerium oxide nanoparticles (nanoceria) possess catalytic and regenerative radical scavenging activities. The ability of nanoceria to maintain cellular redox balance makes them ideal candidates for treatment of retinal diseases whose development is tightly associated with oxidative damage. We have demonstrated that our stable water-dispersed nanoceria delay photoreceptor cell degeneration in rodent models and prevent pathological retinal neovascularization in vldlr mutant mice. The objectives of the current study were to determine the temporal and spatial distributions of nanoceria after a single intravitreal injection, and to determine if nanoceria had any toxic effects in healthy rat retinas. Using inductively-coupled plasma mass spectrometry (ICP-MS), we discovered that nanoceria were rapidly taken up by the retina and were preferentially retained in this tissue even after 120 days. We also did not observe any acute or long-term negative effects of nanoceria on retinal function or cytoarchitecture even after this long-term exposure. Because nanoceria are effective at low dosages, nontoxic and are retained in the retina for extended periods, we conclude that nanoceria are promising ophthalmic therapeutics for treating retinal diseases known to involve oxidative stress in their pathogeneses. PMID:23536794

Adipose-derived mesenchymal stem cells and regenerative medicine.

PubMed

Konno, Masamitsu; Hamabe, Atsushi; Hasegawa, Shinichiro; Ogawa, Hisataka; Fukusumi, Takahito; Nishikawa, Shimpei; Ohta, Katsuya; Kano, Yoshihiro; Ozaki, Miyuki; Noguchi, Yuko; Sakai, Daisuke; Kudoh, Toshihiro; Kawamoto, Koichi; Eguchi, Hidetoshi; Satoh, Taroh; Tanemura, Masahiro; Nagano, Hiroaki; Doki, Yuichiro; Mori, Masaki; Ishii, Hideshi

2013-04-01

Adipose tissue-derived mesenchymal stem cells (ADSCs) are multipotent and can differentiate into various cell types, including osteocytes, adipocytes, neural cells, vascular endothelial cells, cardiomyocytes, pancreatic β-cells, and hepatocytes. Compared with the extraction of other stem cells such as bone marrow-derived mesenchymal stem cells (BMSCs), that of ADSCs requires minimally invasive techniques. In the field of regenerative medicine, the use of autologous cells is preferable to embryonic stem cells or induced pluripotent stem cells. Therefore, ADSCs are a useful resource for drug screening and regenerative medicine. Here we present the methods and mechanisms underlying the induction of multilineage cells from ADSCs. © 2013 The Authors Development, Growth & Differentiation © 2013 Japanese Society of Developmental Biologists.

A dual role of p21 in stem cell aging.

PubMed

Ju, Zhenyu; Choudhury, Aaheli Roy; Rudolph, K Lenhard

2007-04-01

A decline in adult stem cell function occurs during aging, likely contributing to the decline in organ homeostasis and regeneration with age. An emerging field in aging research is to analyze molecular pathways limiting adult stem cell function in response to macromolecular damage accumulation during aging. Current data suggest that the p21 cell cycle inhibitor has a dual role in stem cell aging: On one hand, p21 protects adult stem cells from acute genotoxic stress by preventing inappropriate cycling of acutely damaged stem cells. On the other hand, p21 activation impairs stem cell function and survival of aging telomere dysfunctional mice indicating that p21 checkpoint function is disadvantageous in the context of chronic and persistent damage, which accumulates during aging. This article focuses on these dual roles of p21 in aging stem cells.

Stem Cell Pathology.

PubMed

Fu, Dah-Jiun; Miller, Andrew D; Southard, Teresa L; Flesken-Nikitin, Andrea; Ellenson, Lora H; Nikitin, Alexander Yu

2018-01-24

Rapid advances in stem cell biology and regenerative medicine have opened new opportunities for better understanding disease pathogenesis and the development of new diagnostic, prognostic, and treatment approaches. Many stem cell niches are well defined anatomically, thereby allowing their routine pathological evaluation during disease initiation and progression. Evaluation of the consequences of genetic manipulations in stem cells and investigation of the roles of stem cells in regenerative medicine and pathogenesis of various diseases such as cancer require significant expertise in pathology for accurate interpretation of novel findings. Therefore, there is an urgent need for developing stem cell pathology as a discipline to facilitate stem cell research and regenerative medicine. This review provides examples of anatomically defined niches suitable for evaluation by diagnostic pathologists, describes neoplastic lesions associated with them, and discusses further directions of stem cell pathology.

The clinical use of regenerative therapy in COPD

PubMed Central

Lipsi, Roberto; Rogliani, Paola; Calzetta, Luigino; Segreti, Andrea; Cazzola, Mario

2014-01-01

Regenerative or stem cell therapy is an emerging field of treatment based on stimulation of endogenous resident stem cells or administration of exogenous stem cells to treat diseases or injury and to replace malfunctioning or damaged tissues. Current evidence suggests that in the lung, these cells may participate in tissue homeostasis and regeneration after injury. Animal and human studies have demonstrated that tissue-specific stem cells and bone marrow-derived cells contribute to lung tissue regeneration and protection, and thus administration of exogenous stem/progenitor cells or humoral factors responsible for the activation of endogenous stem/progenitor cells may be a potent next-generation therapy for chronic obstructive pulmonary disease. The use of bone marrow-derived stem cells could allow repairing and regenerate the damaged tissue present in chronic obstructive pulmonary disease by means of their engraftment into the lung. Another approach could be the stimulation of resident stem cells by means of humoral factors or photobiostimulation. PMID:25548520

Plant stem cell niches.

PubMed

Aichinger, Ernst; Kornet, Noortje; Friedrich, Thomas; Laux, Thomas

2012-01-01

Multicellular organisms possess pluripotent stem cells to form new organs, replenish the daily loss of cells, or regenerate organs after injury. Stem cells are maintained in specific environments, the stem cell niches, that provide signals to block differentiation. In plants, stem cell niches are situated in the shoot, root, and vascular meristems-self-perpetuating units of organ formation. Plants' lifelong activity-which, as in the case of trees, can extend over more than a thousand years-requires that a robust regulatory network keep the balance between pluripotent stem cells and differentiating descendants. In this review, we focus on current models in plant stem cell research elaborated during the past two decades, mainly in the model plant Arabidopsis thaliana. We address the roles of mobile signals on transcriptional modules involved in balancing cell fates. In addition, we discuss shared features of and differences between the distinct stem cell niches of Arabidopsis.

Induction of muscle stem cell quiescence by the secreted niche factor Oncostatin M.

PubMed

Sampath, Srinath C; Sampath, Srihari C; Ho, Andrew T V; Corbel, Stéphane Y; Millstone, Joshua D; Lamb, John; Walker, John; Kinzel, Bernd; Schmedt, Christian; Blau, Helen M

2018-04-18

The balance between stem cell quiescence and proliferation in skeletal muscle is tightly controlled, but perturbed in a variety of disease states. Despite progress in identifying activators of stem cell proliferation, the niche factor(s) responsible for quiescence induction remain unclear. Here we report an in vivo imaging-based screen which identifies Oncostatin M (OSM), a member of the interleukin-6 family of cytokines, as a potent inducer of muscle stem cell (MuSC, satellite cell) quiescence. OSM is produced by muscle fibers, induces reversible MuSC cell cycle exit, and maintains stem cell regenerative capacity as judged by serial transplantation. Conditional OSM receptor deletion in satellite cells leads to stem cell depletion and impaired regeneration following injury. These results identify Oncostatin M as a secreted niche factor responsible for quiescence induction, and for the first time establish a direct connection between induction of quiescence, stemness, and transplantation potential in solid organ stem cells.

Nuclear Mechanics and Stem Cell Differentiation.

PubMed

Mao, Xinjian; Gavara, Nuria; Song, Guanbin

2015-12-01

Stem cells are characterized by their self-renewal and multi-lineage differentiation potential. Stem cell differentiation is a prerequisite for the application of stem cells in regenerative medicine and clinical therapy. In addition to chemical stimulation, mechanical cues play a significant role in regulating stem cell differentiation. The integrity of mechanical sensors is necessary for the ability of cells to respond to mechanical signals. The nucleus, the largest and stiffest cellular organelle, interacts with the cytoskeleton as a key mediator of cell mechanics. Nuclear mechanics are involved in the complicated interactions of lamins, chromatin and nucleoskeleton-related proteins. Thus, stem cell differentiation is intimately associated with nuclear mechanics due to its indispensable role in mechanotransduction and mechanical response. This paper reviews several main contributions of nuclear mechanics, highlights the hallmarks of the nuclear mechanics of stem cells, and provides insight into the relationship between nuclear mechanics and stem cell differentiation, which may guide clinical applications in the future.

Parthenogenesis-derived Multipotent Stem Cells Adapted for Tissue Engineering Applications

PubMed Central

Koh, Chester J.; Delo, Dawn M.; Lee, Jang Won; Siddiqui, M. Minhaj; Lanza, Robert P.; Soker, Shay; Yoo, James J.; Atala, Anthony

2009-01-01

Embryonic stem cells are envisioned as a viable source of pluripotent cells for use in regenerative medicine applications when donor tissue is not available. However, most current harvest techniques for embryonic stem cells require the destruction of embryos, which has led to significant political and ethical limitations on their usage. Parthenogenesis, the process by which an egg can develop into an embryo in the absence of sperm, may be a potential source of embryonic stem cells that may avoid some of the political and ethical concerns surrounding embryonic stem cells. Here we provide the technical aspects of embryonic stem cell isolation and expansion from the parthenogenetic activation of oocytes. These cells were characterized for their stem-cell properties. In addition, these cells were induced to differentiate to the myogenic, osteogenic, adipogenic, and endothelial lineages, and were able to form muscle-like and bony-like tissue in vivo. Furthermore, parthenogenetic stem cells were able to integrate into injured muscle tissue. Together, these results demonstrate that parthenogenetic stem cells can be successfully isolated and utilized for various tissue engineering applications. PMID:18799133

The human stem cell hierarchy is defined by a functional dependence on Mcl-1 for self-renewal capacity.

PubMed

Campbell, Clinton J V; Lee, Jung Bok; Levadoux-Martin, Marilyne; Wynder, Tracy; Xenocostas, Anargyros; Leber, Brian; Bhatia, Mickie

2010-09-02

The molecular basis for the unique proliferative and self-renewal properties that hierarchically distinguish human stem cells from progenitors and terminally differentiated cells remains largely unknown. We report a role for the Bcl-2 family member myeloid cell leukemia-1 (Mcl-1) as an indispensable regulator of self-renewal in human stem cells and show that a functional dependence on Mcl-1 defines the human stem cell hierarchy. In vivo pharmacologic targeting of the Bcl-2 family members in human hematopoietic stem cells (HSCs) and human leukemic stem cells reduced stem cell regenerative and self-renewal function. Subsequent protein expression studies showed that, among the Bcl-2 family members, only Mcl-1 was up-regulated exclusively in the human HSC fraction on in vivo regeneration of hematopoiesis. Short hairpin RNA-knockdown of Mcl-1 in human cord blood cells did not affect survival in the HSC or hematopoietic progenitor cell fractions in vitro but specifically reduced the in vivo self-renewal function of human HSCs. Moreover, knockdown of Mcl-1 in ontogenetically primitive human pluripotent stem cells resulted in almost complete ablation of stem cell self-renewal function. Our findings show that Mcl-1 is an essential regulator of stem cell self-renewal in humans and therefore represents an axis for therapeutic interventions.

Fake news portrayals of stem cells and stem cell research.

PubMed

Marcon, Alessandro R; Murdoch, Blake; Caulfield, Timothy

2017-10-01

This study examines how stem cells and stem cell research are portrayed on websites deemed to be purveyors of distorted and dubious information. Content analysis was conducted on 224 articles from 2015 to 2016, compiled by searching with the keywords 'stem cell(s)' on a list of websites flagged for containing either 'fake' or 'junk science' news. Articles contained various exaggerated positive and negative claims about stem cells and stem cell science, health and science related conspiracy theories, and statements promoting fear and mistrust of conventional medicine. Findings demonstrate the existence of organized misinformation networks, which may lead the public away from accurate information and facilitate a polarization of public discourse.

Skin appendage-derived stem cells: cell biology and potential for wound repair.

PubMed

Xie, Jiangfan; Yao, Bin; Han, Yutong; Huang, Sha; Fu, Xiaobing

2016-01-01

Stem cells residing in the epidermis and skin appendages are imperative for skin homeostasis and regeneration. These stem cells also participate in the repair of the epidermis after injuries, inducing restoration of tissue integrity and function of damaged tissue. Unlike epidermis-derived stem cells, comprehensive knowledge about skin appendage-derived stem cells remains limited. In this review, we summarize the current knowledge of skin appendage-derived stem cells, including their fundamental characteristics, their preferentially expressed biomarkers, and their potential contribution involved in wound repair. Finally, we will also discuss current strategies, future applications, and limitations of these stem cells, attempting to provide some perspectives on optimizing the available therapy in cutaneous repair and regeneration.

Paracrine Engineering of Human Explant-Derived Cardiac Stem Cells to Over-Express Stromal-Cell Derived Factor 1α Enhances Myocardial Repair.

PubMed

Tilokee, Everad L; Latham, Nicholas; Jackson, Robyn; Mayfield, Audrey E; Ye, Bin; Mount, Seth; Lam, Buu-Khanh; Suuronen, Erik J; Ruel, Marc; Stewart, Duncan J; Davis, Darryl R

2016-07-01

First generation cardiac stem cell products provide indirect cardiac repair but variably produce key cardioprotective cytokines, such as stromal-cell derived factor 1α, which opens the prospect of maximizing up-front paracrine-mediated repair. The mesenchymal subpopulation within explant derived human cardiac stem cells underwent lentiviral mediated gene transfer of stromal-cell derived factor 1α. Unlike previous unsuccessful attempts to increase efficacy by boosting the paracrine signature of cardiac stem cells, cytokine profiling revealed that stromal-cell derived factor 1α over-expression prevented lv-mediated "loss of cytokines" through autocrine stimulation of CXCR4+ cardiac stem cells. Stromal-cell derived factor 1α enhanced angiogenesis and stem cell recruitment while priming cardiac stem cells to readily adopt a cardiac identity. As compared to injection with unmodified cardiac stem cells, transplant of stromal-cell derived factor 1α enhanced cells into immunodeficient mice improved myocardial function and angiogenesis while reducing scarring. Increases in myocardial stromal-cell derived factor 1α content paralleled reductions in myocyte apoptosis but did not influence long-term engraftment or the fate of transplanted cells. Transplantation of stromal-cell derived factor 1α transduced cardiac stem cells increased the generation of new myocytes, recruitment of bone marrow cells, new myocyte/vessel formation and the salvage of reversibly damaged myocardium to enhance cardiac repair after experimental infarction. Stem Cells 2016;34:1826-1835. © 2016 AlphaMed Press.

Basic Science and Clinical Application of Stem Cells in Veterinary Medicine

NASA Astrophysics Data System (ADS)

Ribitsch, I.; Burk, J.; Delling, U.; Geißler, C.; Gittel, C.; Jülke, H.; Brehm, W.

Stem cells play an important role in veterinary medicine in different ways. Currently several stem cell therapies for animal patients are being developed and some, like the treatment of equine tendinopathies with mesenchymal stem cells (MSCs), have already successfully entered the market. Moreover, animal models are widely used to study the properties and potential of stem cells for possible future applications in human medicine. Therefore, in the young and emerging field of stem cell research, human and veterinary medicine are intrinsically tied to one another. Many of the pioneering innovations in the field of stem cell research are achieved by cooperating teams of human and veterinary medical scientists.

CD34+ Testicular Stromal Cells Support Long-Term Expansion of Embryonic and Adult Stem and Progenitor Cells

PubMed Central

Kim, Jiyeon; Seandel, Marco; Falciatori, Ilaria; Wen, Duancheng; Rafii, Shahin

2010-01-01

Stem cells reside in specialized microenvironments created by supporting stromal cells that orchestrate self-renewal and lineage-specific differentiation. However, the precise identity of the cellular and molecular pathways that support self-renewal of stem cells is not known. For example, long-term culture of prototypical stem cells, such as adult spermatogonial stem and progenitor cells (SPCs), in vitro has been impeded by the lack of an optimal stromal cell line that initiates and sustains proliferation of these cells. Indeed, current methods, including the use of mouse embryonic fibroblasts (MEFs), have not been efficient and have generally led to inconsistent results. Here, we report the establishment of a novel CD34-positive cell line, referred to as JK1, derived from mouse testicular stromal cells that not only facilitated long-term SPC culture but also allowed faithful generation of SPCs and multipotent stem cells. SPCs generated on JK1 maintained key features of germ line stem cells, including expression of PLZF, DAZL, and GCNA. Furthermore, these feeders also promoted the long-term cultivation of other types of primitive cells including multi-potent adult spermatogonial-derived stem cells, pluripotent murine embryonic stem cells, and embryonic germ cells derived from primordial germ cells. Stem cells could be passaged serially and still maintained expression of characteristic markers such as OCT4 and NANOG in vitro, as well as the ability to generate all three germ layers in vivo. These results indicate that the JK1 cell line is capable of promoting long-term culture of primitive cells. As such, this cell line allows for identification of stromal-derived factors that support long-term proliferation of various types of stem cells and constitutes a convenient alternative to other types of feeder layers. PMID:18669907

Personalizing Stem Cell Research and Therapy: The Arduous Road Ahead or Missed Opportunity?

PubMed Central

Patel, S.A.; King, C.C.; Lim, P.K.; Habiba, U.; Dave, M.; Porecha, R.; Rameshwar, P.

2010-01-01

The euphoria of stem cell therapy has diminished, allowing scientists, clinicians and the general public to seriously re-examine how and what types of stem cells would effectively repair damaged tissue, prevent further tissue damage and/or replace lost cells. Importantly, there is a growing recognition that there are substantial person-to-person differences in the outcome of stem cell therapy. Even though the small molecule pharmaceuticals have long remained a primary focus of the personalized medicine research, individualized or targeted use of stem cells to suit a particular individual could help forecast potential failures of the therapy or identify, early on, the individuals who might benefit from stem cell interventions. This would however demand collaboration among several specialties such as pharmacology, immunology, genomics and transplantation medicine. Such transdisciplinary work could also inform how best to achieve efficient and predictable stem cell migration to sites of tissue damage, thereby facilitating tissue repair. This paper discusses the possibility of polarizing immune responses to rationalize and individualize therapy with stem cell interventions, since generalized “one-size-fits-all” therapy is difficult to achieve in the face of the diverse complexities posed by stem cell biology. We also present the challenges to stem cell delivery in the context of the host related factors. Although we focus on the mesenchymal stem cells in this paper, the overarching rationale can be extrapolated to other types of stem cells as well. Hence, the broader purpose of this paper is to initiate a dialogue within the personalized medicine community by expanding the scope of inquiry in the field from pharmaceuticals to stem cells and related cell-based health interventions. PMID:20563265

Genetics of Gonadal Stem Cell Renewal

PubMed Central

Greenspan, Leah Joy; de Cuevas, Margaret

2015-01-01

Stem cells are necessary for the maintenance of many adult tissues. Signals within the stem cell microenvironment, or niche, regulate the self-renewal and differentiation capability of these cells. Misregulation of these signals through mutation or damage can lead to overgrowth or depletion of different stem cell pools. In this review, we focus on the Drosophila testis and ovary, both of which contain well-defined niches, as well as the mouse testis, which has become a more approachable stem cell system with recent technical advances. We discuss the signals that regulate gonadal stem cells in their niches, how these signals mediate self-renewal and differentiation under homeostatic conditions, and how stress, whether from mutations or damage, can cause changes in cell fate and drive stem cell competition. PMID:26355592

Multifaceted Roles of Connexin 43 in Stem Cell Niches.

PubMed

Genet, Nafiisha; Bhatt, Neha; Bourdieu, Antonin; Hirschi, Karen K

2018-01-01

Considerable progress has been made in the field of stem cell research; nonetheless, the use of stem cells for regenerative medicine therapies, for either endogenous tissue repair or cellular grafts post injury, remains a challenge. To better understand how to maintain stem cell potential in vivo and promote differentiation ex vivo, it is fundamentally important to elucidate the interactions between stem cells and their surrounding partners within their distinct niches. Among the vast array of proteins depicted as mediators for cell-to-cell interactions, connexin-comprised gap junctions play pivotal roles in the regulation of stem cell fate both in vivo and in vitro. This review summarizes and illustrates the current knowledge regarding the multifaceted roles of Cx43, specifically, in various stem cell niches.

Optical modulation of transgene expression in retinal pigment epithelium

NASA Astrophysics Data System (ADS)

Palanker, D.; Lavinsky, D.; Chalberg, T.; Mandel, Y.; Huie, P.; Dalal, R.; Marmor, M.

2013-03-01

Over a million people in US alone are visually impaired due to the neovascular form of age-related macular degeneration (AMD). The current treatment is monthly intravitreal injections of a protein which inhibits Vascular Endothelial Growth Factor, thereby slowing progression of the disease. The immense financial and logistical burden of millions of intravitreal injections signifies an urgent need to develop more long-lasting and cost-effective treatments for this and other retinal diseases. Viral transfection of ocular cells allows creation of a "biofactory" that secretes therapeutic proteins. This technique has been proven successful in non-human primates, and is now being evaluated in clinical trials for wet AMD. However, there is a critical need to down-regulate gene expression in the case of total resolution of retinal condition, or if patient has adverse reaction to the trans-gene products. The site for genetic therapy of AMD and many other retinal diseases is the retinal pigment epithelium (RPE). We developed and tested in pigmented rabbits, an optical method to down-regulate transgene expression in RPE following vector delivery, without retinal damage. Microsecond exposures produced by a rapidly scanning laser vaporize melanosomes and destroy a predetermined fraction of the RPE cells selectively. RPE continuity is restored within days by migration and proliferation of adjacent RPE, but since the transgene is not integrated into the nucleus it is not replicated. Thus, the decrease in transgene expression can be precisely determined by the laser pattern density and further reduced by repeated treatment without affecting retinal structure and function.

Cell of Origin and Cancer Stem Cell Phenotype in Medulloblastomas

DTIC Science & Technology

2015-07-01

dominant role over some oncogene function.In addition, we recently reported that cancer stem cells (CSCs)- stem cell like cells in tumors that have stem ... cell properties and tumor initiating ability- retain epigenetic memories of their cells of origin (Chow et al., 2014). We showed that CSCs derived from

Detection of Ultra-Rare Mitochondrial Mutations in Breast Stem Cells by Duplex Sequencing.

PubMed

Ahn, Eun Hyun; Hirohata, Kensen; Kohrn, Brendan F; Fox, Edward J; Chang, Chia-Cheng; Loeb, Lawrence A

2015-01-01

Long-lived adult stem cells could accumulate non-repaired DNA damage or mutations that increase the risk of tumor formation. To date, studies on mutations in stem cells have concentrated on clonal (homoplasmic) mutations and have not focused on rarely occurring stochastic mutations that may accumulate during stem cell dormancy. A major challenge in investigating these rare mutations is that conventional next generation sequencing (NGS) methods have high error rates. We have established a new method termed Duplex Sequencing (DS), which detects mutations with unprecedented accuracy. We present a comprehensive analysis of mitochondrial DNA mutations in human breast normal stem cells and non-stem cells using DS. The vast majority of mutations occur at low frequency and are not detectable by NGS. The most prevalent point mutation types are the C>T/G>A and A>G/T>C transitions. The mutations exhibit a strand bias with higher prevalence of G>A, T>C, and A>C mutations on the light strand of the mitochondrial genome. The overall rare mutation frequency is significantly lower in stem cells than in the corresponding non-stem cells. We have identified common and unique non-homoplasmic mutations between non-stem and stem cells that include new mutations which have not been reported previously. Four mutations found within the MT-ND5 gene (m.12684G>A, m.12705C>T, m.13095T>C, m.13105A>G) are present in all groups of stem and non-stem cells. Two mutations (m.8567T>C, m.10547C>G) are found only in non-stem cells. This first genome-wide analysis of mitochondrial DNA mutations may aid in characterizing human breast normal epithelial cells and serve as a reference for cancer stem cell mutation profiles.

Mesenchymal Stem Cells From Bone Marrow, Adipose Tissue, and Lung Tissue Differentially Mitigate Lung and Distal Organ Damage in Experimental Acute Respiratory Distress Syndrome.

PubMed

Silva, Johnatas D; Lopes-Pacheco, Miquéias; Paz, Ana H R; Cruz, Fernanda F; Melo, Elga B; de Oliveira, Milena V; Xisto, Débora G; Capelozzi, Vera L; Morales, Marcelo M; Pelosi, Paolo; Cirne-Lima, Elizabeth; Rocco, Patricia R M

2018-02-01

Mesenchymal stem cells-based therapies have shown promising effects in experimental acute respiratory distress syndrome. Different mesenchymal stem cells sources may result in diverse effects in respiratory diseases; however, there is no information regarding the best source of mesenchymal stem cells to treat pulmonary acute respiratory distress syndrome. We tested the hypothesis that mesenchymal stem cells derived from bone marrow, adipose tissue, and lung tissue would lead to different beneficial effects on lung and distal organ damage in experimental pulmonary acute respiratory distress syndrome. Animal study and primary cell culture. Laboratory investigation. Seventy-five Wistar rats. Wistar rats received saline (control) or Escherichia coli lipopolysaccharide (acute respiratory distress syndrome) intratracheally. On day 2, acute respiratory distress syndrome animals were further randomized to receive saline or bone marrow, adipose tissue, or lung tissue mesenchymal stem cells (1 × 10 cells) IV. Lung mechanics, histology, and protein levels of inflammatory mediators and growth factors were analyzed 5 days after mesenchymal stem cells administration. RAW 264.7 cells (a macrophage cell line) were incubated with lipopolysaccharide followed by coculture or not with bone marrow, adipose tissue, and lung tissue mesenchymal stem cells (10 cells/mL medium). Regardless of mesenchymal stem cells source, cells administration improved lung function and reduced alveolar collapse, tissue cellularity, collagen, and elastic fiber content in lung tissue, as well as decreased apoptotic cell counts in liver. Bone marrow and adipose tissue mesenchymal stem cells administration also reduced levels of tumor necrosis factor-α, interleukin-1β, keratinocyte-derived chemokine, transforming growth factor-β, and vascular endothelial growth factor, as well as apoptotic cell counts in lung and kidney, while increasing expression of keratinocyte growth factor in lung tissue. Additionally, mesenchymal stem cells differently modulated the secretion of biomarkers by macrophages depending on their source. Mesenchymal stem cells from different sources led to variable responses in lungs and distal organs. Bone marrow and adipose tissue mesenchymal stem cells yielded greater beneficial effects than lung tissue mesenchymal stem cells. These findings may be regarded as promising in clinical trials.

The Role of Tumor Associated Macrophage in Recurrent Growth of Tumor Stem Cell

DTIC Science & Technology

2011-09-01

recent cancer stem cell (CSC) theory, recurrent tumor must arise from a dormant tumor stem cell whose re-growth is triggered by shifting of...microenvironment. This project aims at clarifying the roles of TAM in recurrent growth of dormant stem cell in breast cancer. We hypothesize that the balance of...dormancy and recurrence is determined by the ability of the tumor stem cells to recruit TAM which in turn promotes self-renewal of the stem cell . We

3D modeling of cancer stem cell niche

PubMed Central

He, Jun; Xiong, Li; Li, Qinglong; Lin, Liangwu; Miao, Xiongying; Yan, Shichao; Hong, Zhangyong; Yang, Leping; Wen, Yu; Deng, Xiyun

2018-01-01

Cancer stem cells reside in a distinct microenvironment called niche. The reciprocal interactions between cancer stem cells and niche contribute to the maintenance and enrichment of cancer stem cells. In order to simulate the interactions between cancer stem cells and niche, three-dimensional models have been developed. These in vitro culture systems recapitulate the spatial dimension, cellular heterogeneity, and the molecular networks of the tumor microenvironment and show great promise in elucidating the pathophysiology of cancer stem cells and designing more clinically relavant treatment modalites. PMID:29416698

Stem cells for the treatment of neurodegenerative diseases

PubMed Central

2010-01-01

Stem cells offer an enormous pool of resources for the understanding of the human body. One proposed use of stem cells has been as an autologous therapy. The use of stem cells for neurodegenerative diseases has become of interest. Clinical applications of stem cells for Alzheimer disease, Parkinson disease, amyotrophic lateral sclerosis, and multiple sclerosis will increase in the coming years, and although great care will need to be taken when moving forward with prospective treatments, the application of stem cells is highly promising. PMID:21144012

Stem Cell-based Tissue Engineering Approaches for Musculoskeletal Regeneration

PubMed Central

Brown, Patrick T.; Handorf, Andrew M.; Jeon, Won Bae; Li, Wan-Ju

2014-01-01

The field of regenerative medicine and tissue engineering is an ever evolving field that holds promise in treating numerous musculoskeletal diseases and injuries. An important impetus in the development of the field was the discovery and implementation of stem cells. The utilization of mesenchymal stem cells, and later embryonic and induced pluripotent stem cells, opens new arenas for tissue engineering and presents the potential of developing stem cell-based therapies for disease treatment. Multipotent and pluripotent stem cells can produce various lineage tissues, and allow for derivation of a tissue that may be comprised of multiple cell types. As the field grows, the combination of biomaterial scaffolds and bioreactors provides methods to create an environment for stem cells that better represent their microenvironment for new tissue formation. As technologies for the fabrication of biomaterial scaffolds advance, the ability of scaffolds to modulate stem cell behavior advances as well. The composition of scaffolds could be of natural or synthetic materials and could be tailored to enhance cell self-renewal and/or direct cell fates. In addition to biomaterial scaffolds, studies of tissue development and cellular microenvironments have determined other factors, such as growth factors and oxygen tension, that are crucial to the regulation of stem cell activity. The overarching goal of stem cell-based tissue engineering research is to precisely control differentiation of stem cells in culture. In this article, we review current developments in tissue engineering, focusing on several stem cell sources, induction factors including growth factors, oxygen tension, biomaterials, and mechanical stimulation, and the internal and external regulatory mechanisms that govern proliferation and differentiation. PMID:23432679

Stem Cells for Skeletal Muscle Tissue Engineering.

PubMed

Pantelic, Molly N; Larkin, Lisa M

2018-04-19

Volumetric muscle loss (VML) is a debilitating condition wherein muscle loss overwhelms the body's normal physiological repair mechanism. VML is particularly common among military service members who have sustained war injuries. Because of the high social and medical cost associated with VML and suboptimal current surgical treatments, there is great interest in developing better VML therapies. Skeletal muscle tissue engineering (SMTE) is a promising alternative to traditional VML surgical treatments that use autogenic tissue grafts, and rather uses isolated stem cells with myogenic potential to generate de novo skeletal muscle tissues to treat VML. Satellite cells are the native precursors to skeletal muscle tissue, and are thus the most commonly studied starting source for SMTE. However, satellite cells are difficult to isolate and purify, and it is presently unknown whether they would be a practical source in clinical SMTE applications. Alternative myogenic stem cells, including adipose-derived stem cells, bone marrow-derived mesenchymal stem cells, perivascular stem cells, umbilical cord mesenchymal stem cells, induced pluripotent stem cells, and embryonic stem cells, each have myogenic potential and have been identified as possible starting sources for SMTE, although they have yet to be studied in detail for this purpose. These alternative stem cell varieties offer unique advantages and disadvantages that are worth exploring further to advance the SMTE field toward highly functional, safe, and practical VML treatments. The following review summarizes the current state of satellite cell-based SMTE, details the properties and practical advantages of alternative myogenic stem cells, and offers guidance to tissue engineers on how alternative myogenic stem cells can be incorporated into SMTE research.

Ocular stem cells: a status update!

PubMed Central

2014-01-01

Stem cells are unspecialized cells that have been a major focus of the field of regenerative medicine, opening new frontiers and regarded as the future of medicine. The ophthalmology branch of the medical sciences was the first to directly benefit from stem cells for regenerative treatment. The success stories of regenerative medicine in ophthalmology can be attributed to its accessibility, ease of follow-up and the eye being an immune-privileged organ. Cell-based therapies using stem cells from the ciliary body, iris and sclera are still in animal experimental stages but show potential for replacing degenerated photoreceptors. Limbal, corneal and conjunctival stem cells are still limited for use only for surface reconstruction, although they might have potential beyond this. Iris pigment epithelial, ciliary body epithelial and choroidal epithelial stem cells in laboratory studies have shown some promise for retinal or neural tissue replacement. Trabecular meshwork, orbital and sclera stem cells have properties identical to cells of mesenchymal origin but their potential has yet to be experimentally determined and validated. Retinal and retinal pigment epithelium stem cells remain the most sought out stem cells for curing retinal degenerative disorders, although treatments using them have resulted in variable outcomes. The functional aspects of the therapeutic application of lenticular stem cells are not known and need further attention. Recently, embryonic stem cell-derived retinal pigment epithelium has been used for treating patients with Stargardts disease and age-related macular degeneration. Overall, the different stem cells residing in different components of the eye have shown some success in clinical and animal studies in the field of regenerative medicine. PMID:25158127

Maintenance of sweat glands by stem cells located in the acral epithelium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohe, Shuichi; Department of Dermatology, Kansai Medical University, Osaka 573-1010; Tanaka, Toshihiro

The skin is responsible for a variety of physiological functions and is critical for wound healing and repair. Therefore, the regenerative capacity of the skin is important. However, stem cells responsible for maintaining the acral epithelium had not previously been identified. In this study, we identified the specific stem cells in the acral epithelium that participate in the long-term maintenance of sweat glands, ducts, and interadnexal epidermis and that facilitate the regeneration of these structures following injury. Lgr6-positive cells and Bmi1-positive cells were found to function as long-term multipotent stem cells that maintained the entire eccrine unit and the interadnexalmore » epidermis. However, while Lgr6-positive cells were rapidly cycled and constantly supplied differentiated cells, Bmi1-positive cells were slow to cycle and occasionally entered the cell cycle under physiological conditions. Upon irradiation-induced injury, Bmi1-positive cells rapidly proliferated and regenerated injured epithelial tissue. Therefore, Bmi1-positive stem cells served as reservoir stem cells. Lgr5-positive cells were rapidly cycled and maintained only sweat glands; therefore, we concluded that these cells functioned as lineage-restricted progenitors. Taken together, our data demonstrated the identification of stem cells that maintained the entire acral epithelium and supported the different roles of three cellular classes. - Highlights: • The acral epithelium have two types of stem cells. • Lgr6-positive cells are rapid-cycling, short-term stem cells. • Bmi1-positive cells are slow-cycling stem cells that act as reserver stem cells. • Lgr5 may be a useful sweat gland marker in mice.« less

Challenges and Opportunities to Harnessing the (Hematopoietic) Stem Cell Niche

PubMed Central

Choi, Ji Sun; Harley, Brendan A. C.

2016-01-01

In our body, stem cells reside in a microenvironment termed the niche. While the exact composition and therefore the level of complexity of a stem cell niche can vary significantly tissue-to-tissue, the stem cell niche microenvironment is dynamic, typically containing spatial and temporal variations in both cellular, extracellular matrix, and biomolecular components. This complex flow of secreted or bound biomolecules, cytokines, extracellular matrix components, and cellular constituents all contribute to the regulation of stem cell fate specification events, making engineering approaches at the nano- and micro-scale of particular interest for creating an artificial niche environment in vitro. Recent advances in fabrication approaches have enabled biomedical researchers to capture and recreate the complexity of stem cell niche microenvironments in vitro. Such engineered platforms show promise as a means to enhance our understanding of the mechanisms underlying niche-mediated stem cell regulation as well as offer opportunities to precisely control stem cell expansion and differentiation events for clinical applications. While these principles generally apply to all adult stem cells and niches, in this review, we focus on recent developments in engineering synthetic niche microenvironments for one of the best-characterized stem cell populations, hematopoietic stem cells (HSC). Specifically, we highlight recent advances in platforms designed to facilitate the extrinsic control of HSC fate decisions. PMID:27134819

[Morphofunctional organization of reserve stem cells providing for asexual and sexual reproduction of invertebrates].

PubMed

Isaeva, V V; Akhmadieva, A V; Aleksandriova, Ia N; Shukaliuk, A I

2009-01-01

Published and original data indicating evolutionary conservation of the morphofunctional organization of reserve stem cells providing for asexual and sexual reproduction of invertebrates are reviewed. Stem cells were studied in representatives of five animal types: archeocytes in sponge Oscarella malakhovi (Porifera), large interstitial cells in colonial hydroid Obelia longissima (Cnidaria), neoblasts in an asexual race of planarian Girardia tigrina (Platyhelmintes), stem cells in colonial rhizocephalans Peltogasterella gracilis, Polyascus polygenea, and Thylacoplethus isaevae (Arthropoda), and colonial ascidian Botryllus tuberatus (Chordata). Stem cells in animals of such diverse taxa feature the presence of germinal granules, are positive for proliferating cell nuclear antigen, demonstrate alkaline phosphatase activity (at marker of embryonic stem cells and primary germ cells in vertebrates), and rhizocephalan stem cells express the vasa-like gene (such genes are expressed in germline cells of different metazoans). The self-renewing pool of stem cells is the cellular basis of the reproductive strategy including sexual and asexual reproduction.

The neural stem cell fate determinant TLX promotes tumorigenesis and genesis of cells resembling glioma stem cells.

PubMed

Park, Hyo-Jung; Kim, Jun-Kyum; Jeon, Hye-Min; Oh, Se-Yeong; Kim, Sung-Hak; Nam, Do-Hyun; Kim, Hyunggee

2010-11-01

A growing body of evidence indicates that deregulation of stem cell fate determinants is a hallmark of many types of malignancies. The neural stem cell fate determinant TLX plays a pivotal role in neurogenesis in the adult brain by maintaining neural stem cells. Here, we report a tumorigenic role of TLX in brain tumor initiation and progression. Increased TLX expression was observed in a number of glioma cells and glioma stem cells, and correlated with poor survival of patients with gliomas. Ectopic expression of TLX in the U87MG glioma cell line and Ink4a/Arf-deficient mouse astrocytes (Ink4a/Arf(-/-) astrocytes) induced cell proliferation with a concomitant increase in cyclin D expression, and accelerated foci formation in soft agar and tumor formation in in vivo transplantation assays. Furthermore, overexpression of TLX in Ink4a/Arf(-/-) astrocytes inhibited cell migration and invasion and promoted neurosphere formation and Nestin expression, which are hallmark characteristics of glioma stem cells, under stem cell culture conditions. Our results indicate that TLX is involved in glioma stem cell genesis and represents a potential therapeutic target for this type of malignancy.

First steps to define murine amniotic fluid stem cell microenvironment.

PubMed

Bertin, E; Piccoli, M; Franzin, C; Spiro, G; Donà, S; Dedja, A; Schiavi, F; Taschin, E; Bonaldo, P; Braghetta, P; De Coppi, P; Pozzobon, M

2016-11-15

Stem cell niche refers to the microenvironment where stem cells reside in living organisms. Several elements define the niche and regulate stem cell characteristics, such as stromal support cells, gap junctions, soluble factors, extracellular matrix proteins, blood vessels and neural inputs. In the last years, different studies demonstrated the presence of cKit + cells in human and murine amniotic fluid, which have been defined as amniotic fluid stem (AFS) cells. Firstly, we characterized the murine cKit + cells present both in the amniotic fluid and in the amnion. Secondly, to analyze the AFS cell microenvironment, we injected murine YFP + embryonic stem cells (ESC) into the amniotic fluid of E13.5 wild type embryos. Four days after transplantation we found that YFP + sorted cells maintained the expression of pluripotency markers and that ESC adherent to the amnion were more similar to original ESC in respect to those isolated from the amniotic fluid. Moreover, cytokines evaluation and oxygen concentration analysis revealed in this microenvironment the presence of factors that are considered key regulators in stem cell niches. This is the first indication that AFS cells reside in a microenvironment that possess specific characteristics able to maintain stemness of resident and exogenous stem cells.

Identification and isolation of adult liver stem/progenitor cells.

PubMed

Tanaka, Minoru; Miyajima, Atsushi

2012-01-01

Hepatoblasts are considered to be liver stem/progenitor cells in the fetus because they propagate and differentiate into two types of liver epithelial cells, hepatocytes and cholangiocytes. In adults, oval cells that emerge in severely injured liver are considered facultative hepatic stem/progenitor cells. However, the nature of oval cells has remained unclear for long time due to the lack of a method to isolate them. It has also been unclear whether liver stem/progenitor cells exist in normal adult liver. Recently, we and others have successfully identified oval cells and adult liver stem/progenitor cells. Here, we describe the identification and isolation of mouse liver stem/progenitor cells by utilizing antibodies against specific cell surface marker molecules.

Evaluation of the maintenance of stemness, viability, and differentiation potential of gingiva-derived stem-cell spheroids.

PubMed

Lee, Sung-Il; Ko, Youngkyung; Park, Jun-Beom

2017-05-01

Gingiva-derived stem cells have been applied for tissue-engineering purposes and may be considered a favorable source of mesenchymal stem cells as harvesting stem cells from the mandible or maxilla may be performed with ease under local anesthesia. The present study was performed to fabricate stem-cell spheroids using concave microwells and to evaluate the maintenance of stemness, viability, and differentiation potential. Gingiva-derived stem cells were isolated, and the stem cells of 4×10 5 (group A) or 8×10 5 (group B) cells were seeded into polydimethylsiloxane-based, concave micromolds with 600 µm diameters. The morphology of the microspheres and the change of the diameters of the spheroids were evaluated. The viability of spheroids was qualitatively analyzed via Live/Dead kit assay. A cell viability analysis was performed on days 1, 3, 6, and 12 with Cell Counting Kit-8. The maintenance of stemness was evaluated with immunocytochemical staining using SSEA-4, TRA-1-60(R) (positive markers), and SSEA-1 (negative marker). Osteogenic, adipogenic, and chondrogenic differentiation potential was evaluated by incubating spheroids in osteogenic, adipogenic and chondrogenic induction medium, respectively. The gingiva-derived stem cells formed spheroids in the concave microwells. The diameters of the spheroids were larger in group A than in group B. The majority of cells in the spheroids emitted green fluorescence, indicating the presence of live cells at day 6. At day 12, the majority of cells in the spheroids emitted green fluorescence, and a small portion of red fluorescence was also noted, which indicated the presence of dead cells. The spheroids were positive for the stem-cell markers SSEA-4 and TRA-1-60(R) and were negative for SSEA-1, suggesting that these spheroids primarily contained undifferentiated human stem cells. Osteogenic, adipogenic, and chondrogenic differentiation was more evident with an increase of incubation time: Mineralized extracellular deposits were observed following Alizarin Red S staining at days 14 and 21; oil globules were increased at day 18 when compared with day 6; and Alcian blue staining was more evident at day 18 when compared with day 6. Within the limits of this study, stem-cell spheroids from gingival cells maintained the stemness, viability, and differentiation potential during the experimental periods. This method may be applied for a promising strategy for stem-cell therapy.

Evaluation of the osteogenic differentiation of gingiva-derived stem cells grown on culture plates or in stem cell spheroids: Comparison of two- and three-dimensional cultures.

PubMed

Lee, Sung-Il; Ko, Youngkyung; Park, Jun-Beom

2017-09-01

Three-dimensional cell culture systems provide a convenient in vitro model for the study of complex cell-cell and cell-matrix interactions in the absence of exogenous substrates. The current study aimed to evaluate the osteogenic differentiation potential of gingiva-derived stem cells cultured in two-dimensional or three-dimensional systems. To the best of our knowledge, the present study is the first to compare the growth of gingiva-derived stem cells in monolayer culture to a three-dimensional culture system with microwells. For three-dimensional culture, gingiva-derived stem cells were isolated and seeded into polydimethylsiloxane-based concave micromolds. Alkaline phosphatase activity and alizarin red S staining assays were then performed to evaluate osteogenesis and the degree of mineralization, respectively. Stem cell spheroids had a significantly increased level of alkaline phosphatase activity and mineralization compared with cells from the two-dimensional culture. In addition, an increase in mineralized deposits was observed with an increase in the loading cell number. The results of present study indicate that gingiva-derived stem cell spheroids exhibit an increased osteogenic potential compared with stem cells from two-dimensional culture. This highlights the potential of three-dimensional culture systems using gingiva-derived stem cells for regenerative medicine applications requiring stem cells with osteogenic potential.

[Embryonic stem cells and therapeutic cloning].

PubMed

Sunde, A; Eftedal, I

2001-08-30

Increased interest in the therapeutic use of human stem cells has emerged following significant progress in ongoing research. The cloning of a sheep, the isolation of human embryonic stem cells, and the discovery that adult stem cells may be reprogrammed taken together give substance to hopes that novel principles of treatment may be developed for a variety of serious conditions. Embryonic stem cells are derived from pre-embryos at the blastocyst stage and may give rise to all bodily tissues and cells. Animal models have demonstrated that embryonic stem cells when transplanted into adult hosts may differentiate and develop into cells and tissues applicable for treatment of a variety of conditions, including Parkinson's disease, multiple sclerosis, spinal injuries, cardiac stroke and cancer. Transplanted embryonic stem cells are exposed to immune reactions similar to those acting on organ transplants, hence immunosuppression of the recipient is generally required. It is, however, possible to obtain embryonic stem cells that are genetically identical to the patient's own cells by means of therapeutic cloning techniques. The nucleus from a somatic cell is transferred into an egg after removal of the egg's own genetic material. Under specific condition the egg will use genetic information from the somatic cell in organising the formation of a blastocyst which in turn generates embryonic stem cells. These cells have a genetic composition identical to that of the patient and are suitable for stem cell therapy.

Development of bioengineering system for stem cell proliferation

NASA Astrophysics Data System (ADS)

Park, H. S.; Shah, R.; Shah, C.

2016-08-01

From last decades, intensive research in the field of stem cells proliferation had been promoted due to the unique property of stem cells to self-renew themselves into multiples and has potential to replicate into an organ or tissues and so it's highly demanding though challenging. Bioreactor, a mechanical device, works as a womb for stem cell proliferation by providing nutritious environment for the proper growth of stem cells. Various factors affecting stem cells growth are the bioreactor mechanism, feeding of continuous nutrients, healthy environment, etc., but it always remains a challenge for controlling biological parameters. The present paper unveils the design of mechanical device commonly known as bioreactor in tissues engineering and biotech field, use for proliferation of stem cells and imparts the proper growing condition for stem cells. This high functional bioreactor provides automation mixing of cell culture and stem cells. This design operates in conjunction with mechanism of reciprocating motion. Compare to commercial bioreactors, this proposed design is more convenient, easy to operate and less maintenance is required as bioreactor culture bag is made of polyethylene which is single use purpose. Development of this bioengineering system will be beneficial for better growth and expansion of stem cell

Stem Cell Therapy in Bladder Dysfunction: Where Are We? And Where Do We Have to Go?

PubMed Central

Lee, Sang-Rae; Song, Yun Seob; Lee, Hong Jun

2013-01-01

To date, stem cell therapy for the bladder has been conducted mainly on an experimental basis in the areas of bladder dysfunction. The therapeutic efficacy of stem cells was originally thought to be derived from their ability to differentiate into various cell types. Studies about stem cell therapy for bladder dysfunction have been limited to an experimental basis and have been less focused than bladder regeneration. Bladder dysfunction was listed in MESH as “urinary bladder neck obstruction”, “urinary bladder, overactive”, and “urinary bladder, neurogenic”. Using those keywords, several articles were searched and studied. The bladder dysfunction model includes bladder outlet obstruction, cryoinjured, diabetes, ischemia, and spinal cord injury. Adipose derived stem cells (ADSCs), bone marrow stem cells (BMSCs), and skeletal muscle derived stem cells (SkMSCs) are used for transplantation to treat bladder dysfunction. The main mechanisms of stem cells to reconstitute or restore bladder dysfunction are migration, differentiation, and paracrine effects. The aim of this study is to review the stem cell therapy for bladder dysfunction and to provide the status of stem cell therapy for bladder dysfunction. PMID:24151627

Mesenchymal stem cells induce dermal fibroblast responses to injury

PubMed Central

Smith, Andria N.; Willis, Elise; Chan, Vincent T.; Muffley, Lara A.; Isik, F. Frank; Gibran, Nicole S.; Hocking, Anne M.

2009-01-01

Although bone marrow-derived mesenchymal stem cells have been shown to promote repair when applied to cutaneous wounds, the mechanism for this response remains to be determined. The aim of this study was to determine the effects of paracrine signaling from mesenchymal stem cells on dermal fibroblast responses to injury including proliferation, migration and expression of genes important in wound repair. Dermal fibroblasts were co-cultured with bone marrow-derived mesenchymal stem cells grown in inserts, which allowed for paracrine interactions without direct cell contact. In this co-culture model, bone marrow-derived mesenchymal stem cells regulate dermal fibroblast proliferation, migration and gene expression. When co-cultured with mesenchymal stem cells, dermal fibroblasts show increased proliferation and accelerated migration in a scratch assay. A chemotaxis assay also demonstrated that dermal fibroblasts migrate towards bone marrow-derived mesenchymal stem cells. A PCR array was used to analyze the effect of mesenchymal stem cells on dermal fibroblast gene expression. In response to mesenchymal stem cells, dermal fibroblasts up-regulate integrin alpha 7 expression and down-regulate expression of ICAM1, VCAM1 and MMP11. These observations suggest that mesenchymal stem cells may provide an important early signal for dermal fibroblast responses to cutaneous injury. PMID:19666021

Application of stem cells in targeted therapy of breast cancer: a systematic review.

PubMed

Madjd, Zahra; Gheytanchi, Elmira; Erfani, Elham; Asadi-Lari, Mohsen

2013-01-01

The aim of this systematic review was to investigate whether stem cells could be effectively applied in targeted therapy of breast cancer. A systematic literature search was performed for original articles published from January 2007 until May 2012. Nine studies met the inclusion criteria for phase I or II clinical trials, of which three used stem cells as vehicles, two trials used autologous hematopoetic stem cells and in four trials cancer stem cells were targeted. Mesenchymal stem cells (MSCs) were applied as cellular vehicles to transfer therapeutic agents. Cell therapy with MSC can successfully target resistant cancers. Cancer stem cells were selectively targeted via a proteasome-dependent suicide gene leading to tumor regression. Wnt/β-catenin signaling pathway has been also evidenced to be an attractive CSC-target. This systematic review focused on two different concepts of stem cells and breast cancer marking a turning point in the trials that applied stem cells as cellular vehicles for targeted delivery therapy as well as CSC-targeted therapies. Applying stem cells as targeted therapy could be an effective therapeutic approach for treatment of breast cancer in the clinic and in therapeutic marketing; however this needs to be confirmed with further clinical investigations.

Applications of stem cell biology to oculoplastic surgery.

PubMed

Daniel, Michael G; Wu, Albert Y

2016-09-01

The review examines the utility of stem cell biology in ophthalmology and oculoplastic surgery. The applicability of stem cell biology varies across a range of different subfields within ophthalmology and oculoplastic surgery. Resident stem cells have been identified in the lacrimal gland, corneal limbus, orbital fat, and muscles of the eye, and can potentially be applied for in-vitro cell and organ cultures with the intent of disease modeling and transplants. The discovery of adipocyte-derived stem cells offered a potentially powerful tool for a variety of oculoplastic applications, such as wound healing, skin rejuvenation, and burn therapeutics. Several groups are currently identifying new uses for stem cells in oculoplastic surgery. The need for stem cell treatment spans a wide array of subfields within ophthalmology, ranging from reconstruction of the eyelid to the generation of artificial lacrimal glands and oncological therapeutics. The advent of induced pluripotent stem cells opened the realm of regenerative medicine, making the modeling of patient-specific diseases a possibility. The identification and characterization of endogenous stem cell populations in the eye makes it possible to obtain specific tissues through induced pluripotent stem cells differentiation, permitting their use in transplants for oculoplastic surgery.

[Bioethical challenges of stem cell tourism].

PubMed

Ventura-Juncá, Patricio; Erices, Alejandro; Santos, Manuel J

2013-08-01

Stem cells have drawn extraordinary attention from scientists and the general public due to their potential to generate effective therapies for incurable diseases. At the same time, the production of embryonic stem cells involves a serious ethical issue concerning the destruction of human embryos. Although adult stem cells and induced pluripotential cells do not pose this ethical objection, there are other bioethical challenges common to all types of stem cells related particularly to the clinical use of stem cells. Their clinical use should be based on clinical trials, and in special situations, medical innovation, both of which have particular ethical dimensions. The media has raised unfounded expectations in patients and the public about the real clinical benefits of stem cells. At the same time, the number of unregulated clinics is increasing around the world, making direct offers through Internet of unproven stem cell therapies that attract desperate patients that have not found solutions in standard medicine. This is what is called stem cells tourism. This article reviews this situation, its consequences and the need for international cooperation to establish effective regulations to prevent the exploitation of patients and to endanger the prestige of legitimate stem cell research.

[Breakthrough in research on pluripotent stem cells and their application in medicine].

PubMed

Valdimarsdóttir, Guðrún; Richter, Anne

2015-12-01

Embryonic stem cells are, as the name indicates, isolated from embryos. They are pluripotent cells which can be maintained undifferentiated or induced to differentiate into any cell type of the body. In 1998 the first isolation of human embryonic stem cells was successful and they became an interesting source for stem cell regenerative medicine. Only 8 years later pluripotent stem cells were generated by reprogramming somatic cells into induced pluripotent stem cells (iPSCs). This was a revolution in the way people thought of cell commitment during development. Since then, a lot of research has been done in understanding the molecular biology of pluripotent stem cells. iPSCs can be generated from somatic cells of a patient and therefore have the same genome. Hence, iPSCs have great potential application in medicine, as they can be utilized in disease modelling, drug screening and cell replacement therapy.

Cell motion predicts human epidermal stemness

PubMed Central

Toki, Fujio; Tate, Sota; Imai, Matome; Matsushita, Natsuki; Shiraishi, Ken; Sayama, Koji; Toki, Hiroshi; Higashiyama, Shigeki

2015-01-01

Image-based identification of cultured stem cells and noninvasive evaluation of their proliferative capacity advance cell therapy and stem cell research. Here we demonstrate that human keratinocyte stem cells can be identified in situ by analyzing cell motion during their cultivation. Modeling experiments suggested that the clonal type of cultured human clonogenic keratinocytes can be efficiently determined by analysis of early cell movement. Image analysis experiments demonstrated that keratinocyte stem cells indeed display a unique rotational movement that can be identified as early as the two-cell stage colony. We also demonstrate that α6 integrin is required for both rotational and collective cell motion. Our experiments provide, for the first time, strong evidence that cell motion and epidermal stemness are linked. We conclude that early identification of human keratinocyte stem cells by image analysis of cell movement is a valid parameter for quality control of cultured keratinocytes for transplantation. PMID:25897083

Limbal Stem Cell Deficiency and Treatment with Stem Cell Transplantation.

PubMed

Barut Selver, Özlem; Yağcı, Ayşe; Eğrilmez, Sait; Gürdal, Mehmet; Palamar, Melis; Çavuşoğlu, Türker; Ateş, Utku; Veral, Ali; Güven, Çağrı; Wolosin, Jose Mario

2017-10-01

The cornea is the outermost tissue of the eye and it must be transparent for the maintenance of good visual function. The superficial epithelium of the cornea, which is renewed continuously by corneal stem cells, plays a critical role in the permanence of this transparency. These stem cells are localized at the cornea-conjunctival transition zone, referred to as the limbus. When this zone is affected/destroyed, limbal stem cell deficiency ensues. Loss of limbal stem cell function allows colonization of the corneal surface by conjunctival epithelium. Over 6 million people worldwide are affected by corneal blindness, and limbal stem cell deficiency is one of the main causes. Fortunately, it is becoming possible to recover vision by autologous transplantation of limbal cells obtained from the contralateral eye in unilateral cases. Due to the potential risks to the donor eye, only a small amount of tissue can be obtained, in which only 1-2% of the limbal epithelial cells are actually limbal stem cells. Vigorous attempts are being made to expand limbal stem cells in culture to preserve or even enrich the stem cell population. Ex vivo expanded limbal stem cell treatment in limbal stem cell deficiency was first reported in 1997. In the 20 years since, various protocols have been developed for the cultivation of limbal epithelial cells. It is still not clear which method promotes effective stem cell viability and this remains a subject of ongoing research. The most preferred technique for limbal cell culture is the explant culture model. In this approach, a small donor eye limbal biopsy is placed as an explant onto a biocompatible substrate (preferably human amniotic membrane) for expansion. The outgrowth (cultivated limbal epithelial cells) is then surgically transferred to the recipient eye. Due to changing regulations concerning cell-based therapy, the implementation of cultivated limbal epithelial transplantation in accordance with Good Laboratory Practice using xenobiotic-free systems is becoming widely accepted both in Turkey and worldwide.

"Mouse Clone Model" for evaluating the immunogenicity and tumorigenicity of pluripotent stem cells.

PubMed

Zhang, Gang; Zhang, Yi

2015-12-18

To investigate the immune-rejection and tumor-formation potentials of induced pluripotent stem cells and other stem cells, we devised a model-designated the "Mouse Clone Model"-which combined the theory of somatic animal cloning, tetraploid complementation, and induced pluripotent stem cells to demonstrate the applicability of stem cells for transplantation therapy.

Elucidating the identity and behavior of spermatogenic stem cells in the mouse testis.

PubMed

Yoshida, Shosei

2012-09-01

Spermatogenesis in mice and other mammalians is supported by a robust stem cell system. Stem cells maintain themselves and continue to produce progeny that will differentiate into sperm over a long period. The pioneering studies conducted from the 1950s to the 1970s, which were based largely on extensive morphological analyses, have established the fundamentals of mammalian spermatogenesis and its stem cells. The prevailing so-called A(single) (A(s)) model, which was originally established in 1971, proposes that singly isolated A(s) spermatogonia are in fact the stem cells. In 1994, the first functional stem cell assay was established based on the formation of repopulating colonies after transplantation in germ cell-depleted host testes, which substantially accelerated the understanding of spermatogenic stem cells. However, because testicular tissues are dissociated into single-cell suspension before transplantation, it was impossible to evaluate the A(s) and other classical models solely by this technique. From 2007 onwards, functional assessment of stem cells without destroying the tissue architecture has become feasible by means of pulse-labeling and live-imaging strategies. Results obtained from these experiments have been challenging the classical thought of stem cells, in which stem cells are a limited number of specialized cells undergoing asymmetric division to produce one self-renewing and one differentiating daughter cells. In contrast, the emerging data suggest that an extended and heterogeneous population of cells exhibiting different degrees of self-renewing and differentiating probabilities forms a reversible, flexible, and stochastic stem cell system as a population. These features may lead to establishment of a more universal principle on stem cells that is shared by other systems.