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Sample records for reversible hepatocyte hypertrophy

  1. Indole-3-carbinol, but not its major digestive product 3,3'-diindolylmethane, induces reversible hepatocyte hypertrophy and cytochromes P450

    SciTech Connect

    Crowell, James A. . E-mail: jc94h@nih.gov; Page, John G.; Levine, Barry S.; Tomlinson, Michael J.; Hebert, Charles D.

    2006-03-01

    Indole-3-carbinol (I-3-C) and 3,3'-diindolylmethane (DIM) have been shown to reduce the incidence and multiplicity of cancers in laboratory animal models. Based on the observation that I-3-C induced hepatocyte hypertrophy when administered orally for 13 weeks to rats, a treatment and recovery study was undertaken to test the hypothesis that the induction of hepatocyte hypertrophy and cytochrome P450 (CYP) activity by I-3-C are adaptive, reversible responses. Additionally, we directly compared the effects of I-3-C to those of its principle metabolite DIM. Rats were treated orally for 28 days with 2 doses of I-3-C (5 and 50 mg I-3-C/kg body weight/day) and DIM (7.5 and 75 mg DIM/kg body weight/day) and then one-half of the animals were not treated for an additional 28 days. Organ weights, histopathology, and the CYP enzyme activities of 1A1/2, 2B1/2, 2C9, 2D6, 2E1, 3A4, and 19 A were measured both after treatment and after recovery. Oral administration of 50 mg I-3-C/kg body weight/day to rats for 28 days significantly increased liver weights and CYP enzyme activities. The effects in males were more pronounced and persistent after recovery than the effects in females. The increased organ weights returned to control values after treatment. Conversely, DIM did not alter liver weights and had no effect on CYP activities after the 28-day treatment. Some changes in CYP activities were measured after the DIM recovery period but the magnitudes of the changes were considered biologically insignificant. The results show that I-3-C, but not DIM, induces reversible adaptive responses in the liver.

  2. Effect of hepatocyte growth factor and angiotensin II on rat cardiomyocyte hypertrophy

    PubMed Central

    Chen, Ai-Lan; Ou, Cai-Wen; He, Zhao-Chu; Liu, Qi-Cai; Dong, Qi; Chen, Min-Sheng

    2012-01-01

    Angiotensin II (Ang II) plays an important role in cardiomyocyte hypertrophy. The combined effect of hepatocyte growth factor (HGF) and Ang II on cardiomyocytes is unknown. The present study was designed to determine the effect of HGF on cardiomyocyte hypertrophy and to explore the combined effect of HGF and Ang II on cardiomyocyte hypertrophy. Primary cardiomyocytes were isolated from neonatal rat hearts and cultured in vitro. Cells were treated with Ang II (1 µM) alone, HGF (10 ng/mL) alone, and Ang II (1 µM) plus HGF (10 ng/mL) for 24, 48, and 72 h. The amount of [3H]-leucine incorporation was then measured to evaluate protein synthesis. The mRNA levels of β-myosin heavy chain and atrial natriuretic factor were determined by real-time PCR to evaluate the presence of fetal phenotypes of gene expression. The cell size of cardiomyocytes was also studied. Ang II (1 µM) increased cardiomyocyte hypertrophy. Similar to Ang II, treatment with 1 µM HGF promoted cardiomyocyte hypertrophy. Moreover, the combination of 1 µM Ang II and 10 ng/mL HGF clearly induced a combined pro-hypertrophy effect on cardiomyocytes. The present study demonstrates for the first time a novel, combined effect of HGF and Ang II in promoting cardiomyocyte hypertrophy. PMID:23044624

  3. Growth Differentiation Factor 11 is a Circulating Factor that Reverses Age-Related Cardiac Hypertrophy

    PubMed Central

    Loffredo, Francesco S.; Steinhauser, Matthew L.; Jay, Steven M.; Gannon, Joseph; Pancoast, James R.; Yalamanchi, Pratyusha; Sinha, Manisha; Dall’Osso, Claudia; Khong, Danika; Shadrach, Jennifer L.; Miller, Christine M.; Singer, Britta S.; Stewart, Alex; Psychogios, Nikolaos; Gerszten, Robert E.; Hartigan, Adam J.; Kim, Mi-Jeong; Serwold, Thomas; Wagers, Amy J.; Lee, Richard T.

    2013-01-01

    Summary The most common form of heart failure occurs with normal systolic function and often involves cardiac hypertrophy in the elderly. To clarify the biological mechanisms that drive cardiac hypertrophy in aging, we tested the influence of circulating factors using heterochronic parabiosis, a surgical technique in which joining of animals of different ages leads to a shared circulation. After 4 weeks of exposure to the circulation of young mice, cardiac hypertrophy in old mice dramatically regressed, accompanied by reduced cardiomyocyte size and molecular remodeling. Reversal of age-related hypertrophy was not attributable to hemodynamic or behavioral effects of parabiosis, implicating a blood-borne factor. Using modified aptamer-based proteomics, we identified the TGFβ superfamily member GDF11 as a circulating factor in young mice that declines with age. Treatment of old mice to restore GDF11 to youthful levels recapitulated the effects of parabiosis and reversed age-related hypertrophy, revealing a new therapeutic opportunity for cardiac aging. PMID:23663781

  4. Carbon Tetrachloride at Hepatotoxic Levels Blocks Reversibly Gap Junctions between Rat Hepatocytes

    NASA Astrophysics Data System (ADS)

    Saez, J. C.; Bennett, M. V. L.; Spray, D. C.

    1987-05-01

    Electrical coupling and dye coupling between pairs of rat hepatocytes were reversibly reduced by brief exposure to halogenated methanes (CBrCl3, CCl4, and CHCl3). The potency of different halomethanes in uncoupling hepatocytes was comparable to their hepatotoxicity in vivo, and the rank order was the same as that of their tendency to form free radicals. The effect of carbon tetrachloride (CCl4) on hepatocytes was substantially reduced by prior treatment with SKF 525A, an inhibitor of cytochrome P-450, and by exposure to the reducing reagent β -mercaptoethanol. Halomethane uncoupling occurred with or without extracellular calcium and did not change intracellular concentrations of calcium and hydrogen ions or the phosphorylation state of the main gap-junctional protein. Thus the uncoupling appears to depend on cytochrome P-450 oxidative metabolism in which free radicals are generated and may result from oxidation of the gap-junctional protein or of a regulatory molecule that leads to closure of gap-junctional channels. Decreases in junctional conductance may be a rapid cellular response to injury that protects healthy cells by uncoupling them from unhealthy ones.

  5. Serelaxin treatment reverses vascular dysfunction and left ventricular hypertrophy in a mouse model of Type 1 diabetes

    PubMed Central

    Ng, Hooi Hooi; Leo, Chen Huei; Prakoso, Darnel; Qin, Chengxue; Ritchie, Rebecca H.; Parry, Laura J.

    2017-01-01

    Serelaxin prevents endothelial dysfunction in the mouse aorta ex vivo and inhibits apoptosis in cardiomyocytes under acute hyperglycaemia. Less is known about the effects of serelaxin in an in vivo mouse model of diabetes. Therefore, we tested the hypothesis in streptozotocin (STZ)-treated mice that serelaxin is able to reverse diabetes-induced vascular dysfunction and cardiac remodelling. Mice were divided into citrate buffer + placebo, STZ + placebo and STZ + serelaxin (0.5 mg/kg/d, 2 weeks) groups. After 12 weeks of diabetes, sensitivity to the endothelium-dependent agonist acetylcholine (ACh) was reduced in the mesenteric artery. This was accompanied by an enhanced vasoconstrictor prostanoid contribution and a decrease in endothelium-derived hyperpolarisation (EDH)-mediated relaxation. Serelaxin restored endothelial function by increasing nitric oxide (NO)-mediated relaxation but not EDH. It also normalised the contribution of vasoconstrictor prostanoids to endothelial dysfunction and suppressed diabetes-induced hyper-responsiveness of the mesenteric artery to angiotensin II. Similarly, diabetes reduced ACh-evoked NO-mediated relaxation in the aorta which was reversed by serelaxin. In the left ventricle, diabetes promoted apoptosis, hypertrophy and fibrosis; serelaxin treatment reversed this ventricular apoptosis and hypertrophy, but had no effect on fibrosis. In summary, serelaxin reversed diabetes-induced endothelial dysfunction by enhancing NO-mediated relaxation in the mouse vasculature and attenuating left ventricular hypertrophy and apoptosis. PMID:28067255

  6. AMPK Activation Prevents and Reverses Drug-Induced Mitochondrial and Hepatocyte Injury by Promoting Mitochondrial Fusion and Function

    PubMed Central

    Taniane, Caitlin; Farrell, Geoffrey; Arias, Irwin M.; Lippincott-Schwartz, Jennifer; Fu, Dong

    2016-01-01

    Mitochondrial damage is the major factor underlying drug-induced liver disease but whether conditions that thwart mitochondrial injury can prevent or reverse drug-induced liver damage is unclear. A key molecule regulating mitochondria quality control is AMP activated kinase (AMPK). When activated, AMPK causes mitochondria to elongate/fuse and proliferate, with mitochondria now producing more ATP and less reactive oxygen species. Autophagy is also triggered, a process capable of removing damaged/defective mitochondria. To explore whether AMPK activation could potentially prevent or reverse the effects of drug-induced mitochondrial and hepatocellular damage, we added an AMPK activator to collagen sandwich cultures of rat and human hepatocytes exposed to the hepatotoxic drugs, acetaminophen or diclofenac. In the absence of AMPK activation, the drugs caused hepatocytes to lose polarized morphology and have significantly decreased ATP levels and viability. At the subcellular level, mitochondria underwent fragmentation and had decreased membrane potential due to decreased expression of the mitochondrial fusion proteins Mfn1, 2 and/or Opa1. Adding AICAR, a specific AMPK activator, at the time of drug exposure prevented and reversed these effects. The mitochondria became highly fused and ATP production increased, and hepatocytes maintained polarized morphology. In exploring the mechanism responsible for this preventive and reversal effect, we found that AMPK activation prevented drug-mediated decreases in Mfn1, 2 and Opa1. AMPK activation also stimulated autophagy/mitophagy, most significantly in acetaminophen-treated cells. These results suggest that activation of AMPK prevents/reverses drug-induced mitochondrial and hepatocellular damage through regulation of mitochondrial fusion and autophagy, making it a potentially valuable approach for treatment of drug-induced liver injury. PMID:27792760

  7. Differential responses of human hepatocytes to the non-nucleoside HIV-1 reverse transcriptase inhibitor nevirapine.

    PubMed

    Fang, Jia-Long; Beland, Frederick A

    2013-01-01

    Nevirapine is a non-nucleoside reverse transcriptase (RT) inhibitor used for the treatment of AIDS and the prevention of mother-to-child transmission of HIV-1. Despite its therapeutic benefits, treatment with nevirapine has been associated with significant incidences of liver and dermal toxicity. The present study examined the effects of nevirapine on cell growth and death in human hepatocyte HepG2 cells and THLE2 cells and the possible pathways involved in these effects. The concentrations of nevirapine inhibiting 50% cell growth were similar for both cell lines. Nevirapine (0-250 µM) treatment caused a slight increase in the amount of lactate dehydrogenase released into the medium. Apoptotic cell death did not contribute to the decrease in viable cells. Exposing of HepG2 cells to nevirapine caused G2/M phase arrest, and the activity of senescence-associated β-galactosidase was not altered. In THLE2 cells, the percentage of cells in G1/G0 phase was increased and cellular senescence was induced in a concentration-dependent manner. Endogenous non-telomeric RT activity was not detected in either cell line. Western blot analysis indicated lower levels of p53 and phospho-p53 (ser15) in HepG2 cells as compared to THLE2 cells; no significant changes in p53 or phospho-p53 (ser15) were noted with nevirapine treatment. These data demonstrate that nevirapine inhibits cell growth, induces cell cycle arrest at different phases, and has different effects on cellular senescence in HepG2 cells and THLE2 cells. The differential responses appear to be related to differences in the basal levels of p53 in the HepG2 cells and THLE2 cells.

  8. Autophagic sequestration of (/sup 14/C)sucrose, introduced into rat hepatocytes by reversible electro-permeabilization

    SciTech Connect

    Gordon, P.B.; Seglen, P.O.

    1982-11-01

    Isolated rat hepatocytes could be made permeable to small molecules such as (/sup 14/C)sucrose (but not to proteins) but subjecting the cells to repeated discharges in a high-voltage field. During subsequent incubation at 37/sup 0/C, the permeability changes were reversed within 15 min, the electron-injected (/sup 14/C)sucros remaining trapped inside the re-sealed plasma membrane. Autophagic sequestration of (/sup 14/C)sucrose, i.e., the transfer of radioactivity from cytosol to sedimentable vesicles (autophagosomes and lysosomes), could be followed by incubating the (/sup 14/C)sucrose-loaded hepatocytes for up to 2 h at 37/sup 0/C. After incubation, the cells were disrupted by a single high-voltage discharge in electrolyte-free medium (sucrose), and sedimentable cell components were separated from the cytosol by centrifugation through metrizamide. By the use of these methods, which are particularly suitable for the analysis of many small cell samples, it could be shown that (/sup 14/C)sucros was autophagically sequestered in the hepatocytes at a rate of 4-5%/h. The sequestration was nearly completely inhibited by the specific autophagy inhibitor 3-methyladenine.

  9. Effects of tert-butyl hydroperoxide on Ca(2+) ATPase activity in isolated rat hepatocytes and its reversal by antioxidants.

    PubMed

    Singh, Sangram; Agarwal, Richa; Jamal, Farrukh; Mehrotra, Sudhir; Singh, Rakesh

    2012-09-01

    Calcium ions play an importantrole in various physiological processes such as nerve impulse transmission, muscle contraction, hormone action, blood clotting. They ions act as an intracellular second messenger, relaying information within cells to regulate their activity. To understand the mechanism of hepatotoxicity of t-BHP, studies were carried out using freshly isolated rat hepatocytes. The effect of t-BHP on Ca(2+) accumulation and Ca(2+) uptake by rat hepatocytes was monitored using 45Ca(2+). It caused decrease in 15% accumulation of 45Ca(2+) in comparison to the control group. t-BHP also significantly decreased the Ca(2+) ATPase activity in isolated hepatocytes .This decrease in Ca(2+) ATPase activity by t-BHP was reversed 40% by naturally occurring antioxidant glutathione (GSH) and 20% by the synthetic antioxidant butylated hydroxy toluene (BHT). These results indicate that the hepatotoxic action of t-BHP involves oxidative stress as evident by the protection accorded by various antioxidants employed in the study as well as impairment of intracellular calcium homeostasis which can lead to liver cell injury.

  10. Pathological hypertrophy reverses β2-adrenergic receptor-induced angiogenesis in mouse heart

    PubMed Central

    Xu, Qi; Jennings, Nicole L; Sim, Kenneth; Chang, Lisa; Gao, Xiao-Ming; Kiriazis, Helen; Lee, Ying Ying; Nguyen, My-Nhan; Woodcock, Elizabeth A; Zhang, You-Yi; El-Osta, Assam; Dart, Anthony M; Du, Xiao-Jun

    2015-01-01

    β-adrenergic activation and angiogenesis are pivotal for myocardial function but the link between both events remains unclear. The aim of this study was to explore the cardiac angiogenesis profile in a mouse model with cardiomyocyte-restricted overexpression of β2-adrenoceptors (β2-TG), and the effect of cardiac pressure overload. β2-TG mice had heightened cardiac angiogenesis, which was essential for maintenance of the hypercontractile phenotype seen in this model. Relative to controls, cardiomyocytes of β2-TGs showed upregulated expression of vascular endothelial growth factor (VEGF), heightened phosphorylation of cAMP-responsive-element-binding protein (CREB), and increased recruitment of phospho-CREB, CREB-binding protein (CBP), and p300 to the VEGF promoter. However, when hearts were subjected to pressure overload by transverse aortic constriction (TAC), angiogenic signaling in β2-TGs was inhibited within 1 week after TAC. β2-TG hearts, but not controls, exposed to pressure overload for 1–2 weeks showed significant increases from baseline in phosphorylation of Ca2+/calmodulin-dependent kinase II (CaMKIIδ) and protein expression of p53, reduction in CREB phosphorylation, and reduced abundance of phospho-CREB, p300 and CBP recruited to the CREB-responsive element (CRE) site of VEGF promoter. These changes were associated with reduction in both VEGF expression and capillary density. While non-TG mice with TAC developed compensatory hypertrophy, (2-TGs exhibited exaggerated hypertrophic growth at week-1 post-TAC, followed by LV dilatation and reduced fractional shortening measured by serial echocardiography. In conclusion, angiogenesis was enhanced by the cardiomyocyte (2AR/CREB/VEGF signaling pathway. Pressure overload rapidly inhibited this signaling, likely as a consequence of activated CaMKII and p53, leading to impaired angiogenesis and functional decompensation. PMID:25780088

  11. Deficiency of cardiac Acyl-CoA synthetase-1 induces diastolic dysfunction, but pathologic hypertrophy is reversed by rapamycin.

    PubMed

    Paul, David S; Grevengoed, Trisha J; Pascual, Florencia; Ellis, Jessica M; Willis, Monte S; Coleman, Rosalind A

    2014-06-01

    In mice with temporally-induced cardiac-specific deficiency of acyl-CoA synthetase-1 (Acsl1(H-/-)), the heart is unable to oxidize long-chain fatty acids and relies primarily on glucose for energy. These metabolic changes result in the development of both a spontaneous cardiac hypertrophy and increased phosphorylated S6 kinase (S6K), a substrate of the mechanistic target of rapamycin, mTOR. Doppler echocardiography revealed evidence of significant diastolic dysfunction, indicated by a reduced E/A ratio and increased mean performance index, although the deceleration time and the expression of sarco/endoplasmic reticulum calcium ATPase and phospholamban showed no difference between genotypes. To determine the role of mTOR in the development of cardiac hypertrophy, we treated Acsl1(H-/-) mice with rapamycin. Six to eight week old Acsl1(H-/-) mice and their littermate controls were given i.p. tamoxifen to eliminate cardiac Acsl1, then concomitantly treated for 10weeks with i.p. rapamycin or vehicle alone. Rapamycin completely blocked the enhanced ventricular S6K phosphorylation and cardiac hypertrophy and attenuated the expression of hypertrophy-associated fetal genes, including α-skeletal actin and B-type natriuretic peptide. mTOR activation of the related Acsl3 gene, usually associated with pathologic hypertrophy, was also attenuated in the Acsl1(H-/-) hearts, indicating that alternative pathways of fatty acid activation did not compensate for the loss of Acsl1. Compared to controls, Acsl1(H-/-) hearts exhibited an 8-fold higher uptake of 2-deoxy[1-(14)C]glucose and a 35% lower uptake of the fatty acid analog 2-bromo[1-(14)C]palmitate. These data indicate that Acsl1-deficiency causes diastolic dysfunction and that mTOR activation is linked to the development of cardiac hypertrophy in Acsl1(H-/-) mice.

  12. HCV Induces Telomerase Reverse Transcriptase, Increases Its Catalytic Activity, and Promotes Caspase Degradation in Infected Human Hepatocytes

    PubMed Central

    Zhu, Zhaowen; Tran, Huy; Mathahs, M. Meleah; Moninger, Thomas O.; Schmidt, Warren N.

    2017-01-01

    Introduction Telomerase repairs the telomeric ends of chromosomes and is active in nearly all malignant cells. Hepatitis C virus (HCV) is known to be oncogenic and potential interactions with the telomerase system require further study. We determined the effects of HCV infection on human telomerase reverse transcriptase (TERT) expression and enzyme activity in primary human hepatocytes and continuous cell lines. Results Primary human hepatocytes and Huh-7.5 hepatoma cells showed early de novo TERT protein expression 2–4 days after infection and these events coincided with increased TERT promoter activation, TERT mRNA, and telomerase activity. Immunoprecipitation studies demonstrated that NS3-4A protease-helicase, in contrast to core or NS5A, specifically bound to the C-terminal region of TERT through interactions between helicase domain 2 and protease sequences. Increased telomerase activity was noted when NS3-4A was transfected into cells, when added to reconstituted mixtures of TERT and telomerase RNA, and when incubated with high molecular weight telomerase ‘holoenzyme’ complexes. The NS3-4A catalytic effect on telomerase was inhibited with primuline or danoprevir, agents that are known to inhibit NS3 helicase and protease activities respectively. In HCV infected cells, NS3-4A could be specifically recovered with telomerase holoenzyme complexes in contrast to NS5A or core protein. HCV infection also activated the effector caspase 7 which is known to target TERT. Activation coincided with the appearance of lower molecular weight carboxy-terminal fragment(s) of TERT, chiefly sized at 45 kD, which could be inhibited with pancaspase or caspase 7 inhibitors. Conclusions HCV infection induces TERT expression and stimulates telomerase activity in addition to triggering Caspase activity that leads to increased TERT degradation. These activities suggest multiple points whereby the virus can influence neoplasia. The NS3-4A protease-helicase can directly bind to TERT

  13. Dietary fish oil reverse epididymal tissue adiposity, cell hypertrophy and insulin resistance in dyslipemic sucrose fed rat model small star, filled.

    PubMed

    Soria, Ana; Chicco, Adriana; Eugenia D'Alessandro, María; Rossi, Andrea; Lombardo, Yolanda B.

    2002-04-01

    The present work was designed to assess the possible benefits of (7% w/w) dietary fish oil in reversing the morphological and metabolic changes present in the adipose tissue of rats fed an SRD for a long time. With this purpose, in the epididymal fat tissue, we investigated the effect of dietary fish oil upon: i) the number, size and distribution of cells, ii) the basal and stimulated lipolysis, iii) the lipoprotein lipase (LPL) and the glucose 6-phosphate dehydrogenase activities, and iv) the antilipolytic action of insulin. The study was conducted on rats fed an SRD during 120 days with fish oil being isocaloric substituted for corn oil for 90-120 days in half the animals. Permanent hypertriglyceridemia, insulin resistance and abnormal glucose homeostasis were present in the rats before the source of fat in the diet was replaced. The major new findings of this study are the following: i) Dietary fish oil markedly reduced the fat pads mass, the hypertrophy of fat cells and improved the altered cell size distribution. ii) The presence of fish oil in the diet corrected the inhibitory effect of high sucrose diet upon the antilipolytic action of insulin, reduced the "in vitro" enhanced basal lipolysis and normalized isoproterenol-stimulated lipolysis. Fat pads lipoprotein lipase activity decreased reaching values similar to those observed in age-matched controls fed a control diet (CD). These effects were not accompanied by any change in rat body weight. All these data suggest that the dyslipemic rats fed a moderate amount of dietary fish oil constitute a useful animal model to study diet-regulated insulin action.

  14. Hepatocyte differentiation.

    PubMed

    Olsavsky Goyak, Katy M; Laurenzana, Elizabeth M; Omiecinski, Curtis J

    2010-01-01

    Increasingly, research suggests that for certain systems, animal models are insufficient for human toxicology testing. The development of robust, in vitro models of human toxicity is required to decrease our dependence on potentially misleading in vivo animal studies. A critical development in human toxicology testing is the use of human primary hepatocytes to model processes that occur in the intact liver. However, in order to serve as an appropriate model, primary hepatocytes must be maintained in such a way that they persist in their differentiated state. While many hepatocyte culture methods exist, the two-dimensional collagen "sandwich" system combined with a serum-free medium, supplemented with physiological glucocorticoid concentrations, appears to robustly maintain hepatocyte character. Studies in rat and human hepatocytes have shown that when cultured under these conditions, hepatocytes maintain many markers of differentiation including morphology, expression of plasma proteins, hepatic nuclear factors, phase I and II metabolic enzymes. Functionally, these culture conditions also preserve hepatic stress response pathways, such as the SAPK and MAPK pathways, as well as prototypical xenobiotic induction responses. This chapter will briefly review culture methodologies but will primarily focus on hallmark hepatocyte structural, expression and functional markers that characterize the differentiation status of the hepatocyte.

  15. Hepatocyte Polarity

    PubMed Central

    Treyer, Aleksandr; Müsch, Anne

    2013-01-01

    Hepatocytes, like other epithelia, are situated at the interface between the organism’s exterior and the underlying internal milieu and organize the vectorial exchange of macromolecules between these two spaces. To mediate this function, epithelial cells, including hepatocytes, are polarized with distinct luminal domains that are separated by tight junctions from lateral domains engaged in cell-cell adhesion and from basal domains that interact with the underlying extracellular matrix. Despite these universal principles, hepatocytes distinguish themselves from other nonstriated epithelia by their multipolar organization. Each hepatocyte participates in multiple, narrow lumina, the bile canaliculi, and has multiple basal surfaces that face the endothelial lining. Hepatocytes also differ in the mechanism of luminal protein trafficking from other epithelia studied. They lack polarized protein secretion to the luminal domain and target single-spanning and glycosylphosphatidylinositol-anchored bile canalicular membrane proteins via transcytosis from the basolateral domain. We compare this unique hepatic polarity phenotype with that of the more common columnar epithelial organization and review our current knowledge of the signaling mechanisms and the organization of polarized protein trafficking that govern the establishment and maintenance of hepatic polarity. The serine/threonine kinase LKB1, which is activated by the bile acid taurocholate and, in turn, activates adenosine monophosphate kinase-related kinases including AMPK1/2 and Par1 paralogues has emerged as a key determinant of hepatic polarity. We propose that the absence of a hepatocyte basal lamina and differences in cell-cell adhesion signaling that determine the positioning of tight junctions are two crucial determinants for the distinct hepatic and columnar polarity phenotypes. PMID:23720287

  16. High-intensity interval training, but not continuous training, reverses right ventricular hypertrophy and dysfunction in a rat model of pulmonary hypertension.

    PubMed

    Brown, Mary Beth; Neves, Evandro; Long, Gary; Graber, Jeremy; Gladish, Brett; Wiseman, Andrew; Owens, Matthew; Fisher, Amanda J; Presson, Robert G; Petrache, Irina; Kline, Jeffrey; Lahm, Tim

    2017-02-01

    Exercise is beneficial in pulmonary arterial hypertension (PAH), although studies to date indicate little effect on the elevated pulmonary pressures or maladaptive right ventricle (RV) hypertrophy associated with the disease. For chronic left ventricle failure, high-intensity interval training (HIIT) promotes greater endothelial stimulation and superior benefit than customary continuous exercise training (CExT); however, HIIT has not been tested for PAH. Therefore, here we investigated acute and chronic responses to HIIT vs. CExT in a rat model of monocrotaline (MCT)-induced mild PAH. Six weeks of treadmill training (5 times/wk) were performed, as either 30 min HIIT or 60 min low-intensity CExT. To characterize acute hemodynamic responses to the two approaches, novel recordings of simultaneous pulmonary and systemic pressures during running were obtained at pre- and 2, 4, 6, and 8 wk post-MCT using long-term implantable telemetry. MCT-induced decrement in maximal aerobic capacity was ameliorated by both HIIT and CExT, with less pronounced pulmonary vascular remodeling and no increase in RV inflammation or apoptosis observed. Most importantly, only HIIT lowered RV systolic pressure, RV hypertrophy, and total pulmonary resistance, and prompted higher cardiac index that was complemented by a RV increase in the positive inotrope apelin and reduced fibrosis. HIIT prompted a markedly pulsatile pulmonary pressure during running and was associated with greater lung endothelial nitric oxide synthase after 6 wk. We conclude that HIIT may be superior to CExT for improving hemodynamics and maladaptive RV hypertrophy in PAH. HIIT's superior outcomes may be explained by more favorable pulmonary vascular endothelial adaptation to the pulsatile HIIT stimulus.

  17. The reversal of hyperglycemia after transplantation of mouse embryonic stem cells induced into early hepatocyte-like cells in streptozotocin-induced diabetic mice.

    PubMed

    Boroujeni, Nasim Beigi; Hashemi, Seyed Mahmoud; Khaki, Zohreh; Soleimani, Masoud

    2011-04-01

    Cellular replacement therapy is a potential therapeutic strategy for diabetes. In this study, we investigated the effect of transplantation of induced mouse embryonic stem cells (mESCs) into endoderm and early hepatocyte-like cells in streptozotocin (STZ)-diabetic mice. After embryoid body (EB) formation from mESC, the EBs were cultured in the presence of dexamethasone (DEX) and insulin for 4 days then was added acidic fibroblast growth factor (aFGF), hepatocyte growth factor (HGF) and oncostatin M (OSM) for 10 days, respectively. Blood glucose levels, intraperitoneal glucose tolerance (IGT) test and islet histology were assessed. The result revealed that transplantation of induced mESCs into early hepatocyte-like cells could repair pancreatic islets of control group. Blood glucose levels and intraperitoneal glucose tolerance test were significantly improved in test group compared to control group. Furthermore, there was significant increase in the number of islets in test group compared to control group. The findings declare that induced mESCs into endoderm and early hepatocyte-like cells, are appropriate candidate for regenerative therapy of pancreatic islets in type I diabetes.

  18. Periodontitis and myocardial hypertrophy.

    PubMed

    Suzuki, Jun-Ichi; Sato, Hiroki; Kaneko, Makoto; Yoshida, Asuka; Aoyama, Norio; Akimoto, Shouta; Wakayama, Kouji; Kumagai, Hidetoshi; Ikeda, Yuichi; Akazawa, Hiroshi; Izumi, Yuichi; Isobe, Mitsuaki; Komuro, Issei

    2017-04-01

    There is a deep relationship between cardiovascular disease and periodontitis. It has been reported that myocardial hypertrophy may be affected by periodontitis in clinical settings. Although these clinical observations had some study limitations, they strongly suggest a direct association between severity of periodontitis and left ventricular hypertrophy. However, the detailed mechanisms between myocardial hypertrophy and periodontitis have not yet been elucidated. Recently, we demonstrated that periodontal bacteria infection is closely related to myocardial hypertrophy. In murine transverse aortic constriction models, a periodontal pathogen, Aggregatibacter actinomycetemcomitans markedly enhanced cardiac hypertrophy with matrix metalloproteinase-2 activation, while another pathogen Porphyromonas gingivalis (P.g.) did not accelerate these pathological changes. In the isoproterenol-induced myocardial hypertrophy model, P.g. induced myocardial hypertrophy through Toll-like receptor-2 signaling. From our results and other reports, regulation of chronic inflammation induced by periodontitis may have a key role in the treatment of myocardial hypertrophy. In this article, we review the pathophysiological mechanism between myocardial hypertrophy and periodontitis.

  19. Reversals.

    ERIC Educational Resources Information Center

    National Center on Educational Media and Materials for the Handicapped, Columbus, OH.

    Selected from the National Instructional Materials Information System (NIMIS)--a computer based on-line interactive retrieval system on special education materials--the bibliography covers nine materials for remediating reversals in handicapped students at the early childhood and elementary levels. Entries are presented in order of NIMIS accession…

  20. The quantitative distinction of hyperplasia from hypertrophy in hepatomegaly induced in the rat liver by phenobarbital.

    PubMed

    Carthew, P; Edwards, R E; Nolan, B M

    1998-07-01

    A histological method utilizing the optical dissector principle has been developed for determining the absolute numbers of rat hepatocytes in the liver after treatment with phenobarbital (PB). The optical dissector is a technique derived from the "new stereology" used to measure the number of features, in this case hepatocyte nuclear profiles, that are present in a reference volume of tissue. The method has been applied to distinguish between the hepatomegaly that commonly occurs in rodents after treatment with chemicals, due to an increase in the number of cells caused by cell division (hyperplasia), rather than the size of cells (hypertrophy). In the case of PB treatment, the hepatomegaly was found to be partly due to hypertrophy and partly to hyperplasia after 2 weeks of treatment. While the increase in the absolute number of hepatocytes was not significant after 2 weeks, after 12 weeks of treatment with PB the number of hepatocytes was significantly increased, compared to the controls at that time point. PCNA labeling index measurements of liver hepatocytes confirmed that there was a significant increase in the growth fraction of hepatocytes during PB treatment. The induction of hyperplasia can be associated with an increased risk of eventual liver tumor formation, and the distinction of hyperplasia from hypertrophy, using a purely histological method, for the determination of increases in absolute hepatocyte cell numbers, will be useful in assessing whether treatment-related sustained hyperplasia is occurring in the liver, although this methodology could be applied to any organ.

  1. Histopathological image analysis of chemical-induced hepatocellular hypertrophy in mice.

    PubMed

    Asaoka, Yoshiji; Togashi, Yuko; Mutsuga, Mayu; Imura, Naoko; Miyoshi, Tomoya; Miyamoto, Yohei

    2016-04-01

    Chemical-induced hepatocellular hypertrophy is frequently observed in rodents, and is mostly caused by the induction of phase I and phase II drug metabolic enzymes and peroxisomal lipid metabolic enzymes. Liver weight is a sensitive and commonly used marker for detecting hepatocellular hypertrophy, but is also increased by a number of other factors. Histopathological observations subjectively detect changes such as hepatocellular hypertrophy based on the size of a hepatocyte. Therefore, quantitative microscopic observations are required to evaluate histopathological alterations objectively. In the present study, we developed a novel quantitative method for an image analysis of hepatocellular hypertrophy using liver sections stained with hematoxylin and eosin, and demonstrated its usefulness for evaluating hepatocellular hypertrophy induced by phenobarbital (a phase I and phase II enzyme inducer) and clofibrate (a peroxisomal enzyme inducer) in mice. The algorithm of this imaging analysis was designed to recognize an individual hepatocyte through a combination of pixel-based and object-based analyses. Hepatocellular nuclei and the surrounding non-hepatocellular cells were recognized by the pixel-based analysis, while the areas of the recognized hepatocellular nuclei were then expanded until they ran against their expanding neighboring hepatocytes and surrounding non-hepatocellular cells by the object-based analysis. The expanded area of each hepatocellular nucleus was regarded as the size of an individual hepatocyte. The results of this imaging analysis showed that changes in the sizes of hepatocytes corresponded with histopathological observations in phenobarbital and clofibrate-treated mice, and revealed a correlation between hepatocyte size and liver weight. In conclusion, our novel image analysis method is very useful for quantitative evaluations of chemical-induced hepatocellular hypertrophy.

  2. Regression of Pathological Cardiac Hypertrophy: Signaling Pathways and Therapeutic Targets

    PubMed Central

    Hou, Jianglong; Kang, Y. James

    2012-01-01

    Pathological cardiac hypertrophy is a key risk factor for heart failure. It is associated with increased interstitial fibrosis, cell death and cardiac dysfunction. The progression of pathological cardiac hypertrophy has long been considered as irreversible. However, recent clinical observations and experimental studies have produced evidence showing the reversal of pathological cardiac hypertrophy. Left ventricle assist devices used in heart failure patients for bridging to transplantation not only improve peripheral circulation but also often cause reverse remodeling of the geometry and recovery of the function of the heart. Dietary supplementation with physiologically relevant levels of copper can reverse pathological cardiac hypertrophy in mice. Angiogenesis is essential and vascular endothelial growth factor (VEGF) is a constitutive factor for the regression. The action of VEGF is mediated by VEGF receptor-1, whose activation is linked to cyclic GMP-dependent protein kinase-1 (PKG-1) signaling pathways, and inhibition of cyclic GMP degradation leads to regression of pathological cardiac hypertrophy. Most of these pathways are regulated by hypoxia-inducible factor. Potential therapeutic targets for promoting the regression include: promotion of angiogenesis, selective enhancement of VEGF receptor-1 signaling pathways, stimulation of PKG-1 pathways, and sustention of hypoxia-inducible factor transcriptional activity. More exciting insights into the regression of pathological cardiac hypertrophy are emerging. The time of translating the concept of regression of pathological cardiac hypertrophy to clinical practice is coming. PMID:22750195

  3. Hyperplasia vs hypertrophy in tissue regeneration after extensive liver resection

    PubMed Central

    Marongiu, Fabio; Marongiu, Michela; Contini, Antonella; Serra, Monica; Cadoni, Erika; Murgia, Riccardo; Laconi, Ezio

    2017-01-01

    AIM To address to what extent hypertrophy and hyperplasia contribute to liver mass restoration after major tissue loss. METHODS The ability of the liver to regenerate is remarkable on both clinical and biological grounds. Basic mechanisms underlying this process have been intensively investigated. However, it is still debated to what extent hypertrophy and hyperplasia contribute to liver mass restoration after major tissue loss. We addressed this issue using a genetically tagged system. We were able to follow the fate of single transplanted hepatocytes during the regenerative response elicited by 2/3 partial surgical hepatectomy (PH) in rats. Clusters of transplanted cells were 3D reconstructed and their size distribution was evaluated over time after PH. RESULTS Liver size and liver DNA content were largely recovered 10 d post-PH, as expected (e.g., total DNA/liver/100 g b.w. was 6.37 ± 0.21 before PH and returned to 6.10 ± 0.36 10 d after PH). Data indicated that about 2/3 of the original residual hepatocytes entered S-phase in response to PH. Analysis of cluster size distribution at 24, 48, 96 h and 10 d after PH revealed that about half of the remnant hepatocytes completed at least 2 cell cycles. Average size of hepatocytes increased at 24 h (248.50 μm2 ± 7.82 μm2, P = 0.0015), but returned to control values throughout the regenerative process (up to 10 d post-PH, 197.9 μm2 ± 6.44 μm2, P = 0.11). A sizeable fraction of the remnant hepatocyte population does not participate actively in tissue mass restoration. CONCLUSION Hyperplasia stands as the major mechanism contributing to liver mass restoration after PH, with hypertrophy playing a transient role in the process. PMID:28348481

  4. New approaches to the quantitation of hypertrophy and hyperplasia in hepatomegaly.

    PubMed

    Carthew, P; Edwards, R E; Nolan, B M

    1998-12-28

    A histological method utilizing the optical dissector principle has been developed for determining the contribution of hypertrophy and hyperplasia to the hepatomegaly induced by the peroxisome proliferator gemfibrozil. The optical dissector is a technique derived from the 'new stereology' and has been used to estimate the number of hepatocyte nuclear profiles, that are present in a reference volume of tissue. The overall changes due to hypertrophy and hyperplasia in the rat liver after gemfibrozil treatment, did not reach significance, although the zonal hypertrophy change did. This indicated that although there was a 20% increase in liver weight with treatment, the hepatomegaly was caused by a combination of hypertrophy and hyperplasia, neither of which, on its own, was significantly different from the control values. The distinction of hyperplasia from hypertrophy, using a purely histological method, will be useful in assessing whether treatment related sustained hyperplasia is occurring in the liver.

  5. Ventricular hypertrophy in cardiomyopathy.

    PubMed

    Oakley, C

    1971-01-01

    Semantic difficulties arise when hypertrophic obstructive cardiomyopathy is seen without obstruction and with congestive failure, and also when congestive cardiomyopathy is seen with gross hypertrophy but without heart failure. Retention of a small left ventricular cavity and a normal ejection fraction characterizes hypertrophic cardiomyopathy at all stages of the disorder. Congestive cardiomyopathy is recognized by the presence of a dilated left ventricular cavity and reduced ejection fraction regardless of the amount of hypertrophy and the presence or not of heart failure. Longevity in congestive cardiomyopathy seems to be promoted when hypertrophy is great relative to the amount of pump failure as measured by increase in cavity size. Conversely, death in hypertrophic cardiomyopathy is most likely when hypertrophy is greatest at a time when outflow tract obstruction has been replaced by inflow restriction caused by diminishing ventricular distensibility. Hypertrophy is thus beneficial and compensatory in congestive cardiomyopathy, whereas it may be the primary disorder and eventual cause of death in hypertrophic cardiomyopathy. Reasons are given for believing that hypertension may have been the original cause of left ventricular dilatation in some case of congestive cardiomyopathy in which loss of stroke output thenceforward is followed by normotension. Development of severe hypertension in these patients after recovery from a prolonged period of left ventricular failure with normotension lends weight to this hypothesis. No fault has been found in the large or small coronary arteries in either hypertrophic cardiomyopathy or congestive cardiomyopathy when they have been examined in life by selective coronary angiography, or by histological methods in biopsy or post-mortem material. Coronary blood supply may be a limiting factor in the compensatory hypertrophy of congestive cardiomyopathy, and the ability to hypertrophy may explain the better prognosis of some

  6. BET Acetyl-Lysine Binding Proteins Control Pathological Cardiac Hypertrophy

    PubMed Central

    Spiltoir, Jessica I.; Stratton, Matthew S.; Cavasin, Maria A.; Demos-Davies, Kim; Reid, Brian G.; Qi, Jun; Bradner, James E.; McKinsey, Timothy A.

    2014-01-01

    Cardiac hypertrophy is an independent predictor of adverse outcomes in patients with heart failure, and thus represents an attractive target for novel therapeutic intervention. JQ1, a small molecule inhibitor of bromodomain and extraterminal (BET) acetyl-lysine reader proteins, was identified in a high throughput screen designed to discover novel small molecule regulators of cardiomyocyte hypertrophy. JQ1 dose-dependently blocked agonist-dependent hypertrophy of cultured neonatal rat ventricular myocytes (NRVMs) and reversed the prototypical gene program associated with pathological cardiac hypertrophy. JQ1 also blocked left ventricular hypertrophy (LVH) and improved cardiac function in adult mice subjected to transverse aortic constriction (TAC). The BET family consists of BRD2, BRD3, BRD4 and BRDT. BRD4 protein expression was increased during cardiac hypertrophy, and hypertrophic stimuli promoted recruitment of BRD4 to the transcriptional start site (TSS) of the gene encoding atrial natriuretic factor (ANF). Binding of BRD4 to the ANF TSS was associated with increased phosphorylation of local RNA polymerase II. These findings define a novel function for BET proteins as signal-responsive regulators of cardiac hypertrophy, and suggest that small molecule inhibitors of these epigenetic reader proteins have potential as therapeutics for heart failure. PMID:23939492

  7. [Is secondary myocardial hypertrophy a physiological or pathological adaptive mechanism?].

    PubMed

    Krayenbühl, H P

    1982-08-01

    Physiological hypertrophy is present when the increase in myocardial mass resulting from chronic mechanical loading is associated with normal or enhanced myocardial function and myosin ATPase activity. Morphological alterations occurring during the formation of hypertrophy are fully reversible in physiological hypertrophy. In pathological hypertrophy myocardial function and myosin ATPase activity are depressed and morphological changes do not or only incompletely regress following the elimination of the stimulus of hypertrophy. In the experimental animal myocardial hypertrophy resulting from exercise conditioning or slight to moderate ventricular pressure overload fulfills the criteria of physiological hypertrophy. More severe sudden pressure overload is accompanied by depression of contractile function. These pressure overload models have however, little analogy to the more progressive development of pressure loading in humans. In young dogs and in cats with a gradually increasing pressure load, in vivo ventricular ejection fraction remained within normal limits 37 to 60 weeks after banding of the ventricular outflow vessel. In vitro myocardial function evaluated in the hypertrophied papillary muscle was, however, at least in part depressed, notably when hydroxyproline concentration was augmented. Following debanding in rats with aortic constriction hydroxyproline content did not regress suggesting that fibrosis once established is not reversible. In man myocardial hypertrophy from exercise conditioning is associated with normal ventricular function except in older athletes, who may show a subtle reduction in ventricular shortening. Patients with chronic pressure overload from aortic stenosis or volume overload from aortic insufficiency in whom the angiographic muscle mass is severely increased (greater than or equal to 180 g/m2) elicit a depressed left ventricular contractile function. Preserved left ventricular ejection performance in aortic valve disease is

  8. O-GlcNAc signaling is essential for NFAT-mediated transcriptional reprogramming during cardiomyocyte hypertrophy

    PubMed Central

    Facundo, Heberty T.; Brainard, Robert E.; Watson, Lewis J.; Ngoh, Gladys A.; Hamid, Tariq; Prabhu, Sumanth D.

    2012-01-01

    The regulation of cardiomyocyte hypertrophy is a complex interplay among many known and unknown processes. One specific pathway involves the phosphatase calcineurin, which regulates nuclear translocation of the essential cardiac hypertrophy transcription factor, nuclear factor of activated T-cells (NFAT). Although metabolic dysregulation is frequently described during cardiac hypertrophy, limited insights exist regarding various accessory pathways. One metabolically derived signal, beta-O-linked N-acetylglucosamine (O-GlcNAc), has emerged as a highly dynamic posttranslational modification of serine and threonine residues regulating physiological and stress processes. Given the metabolic dysregulation during hypertrophy, we hypothesized that NFAT activation is dependent on O-GlcNAc signaling. Pressure overload-induced hypertrophy (via transverse aortic constriction) in mice or treatment of neonatal rat cardiac myocytes with phenylephrine significantly enhanced global O-GlcNAc signaling. NFAT-luciferase reporter activity revealed O-GlcNAc-dependent NFAT activation during hypertrophy. Reversal of enhanced O-GlcNAc signaling blunted cardiomyocyte NFAT-induced changes during hypertrophy. Taken together, these results demonstrate a critical role of O-GlcNAc signaling in NFAT activation during hypertrophy and provide evidence that O-GlcNAc signaling is coordinated with the onset and progression of cardiac hypertrophy. This represents a potentially significant and novel mechanism of cardiac hypertrophy, which may be of particular interest in future in vivo studies of hypertrophy. PMID:22408028

  9. Mechanism of Hepatocyte Apoptosis

    PubMed Central

    Cao, Lei; Quan, Xi-Bing; Zeng, Wen-Jiao; Yang, Xiao-Ou; Wang, Ming-Jie

    2016-01-01

    Hepatocyte apoptosis plays important roles in both the removal of external microorganisms and the occurrence and development of liver diseases. Different conditions, such as virus infection, fatty liver disease, hepatic ischemia reperfusion, and drug-induced liver injury, are accompanied by hepatocyte apoptosis. This review summarizes recent research on the mechanism of hepatocyte apoptosis involving the classical extrinsic and intrinsic apoptotic pathways, endoplasmic reticulum stress, and oxidative stress-induced apoptosis. We emphasized the major causes of apoptosis according to the characteristics of different liver diseases. Several concerns regarding future research and clinical application are also raised. PMID:28058033

  10. MicroRNA-101 inhibits rat cardiac hypertrophy by targeting Rab1a.

    PubMed

    Wei, Longxiao; Yuan, Menghui; Zhou, Runsuo; Bai, Qianrong; Zhang, Wei; Zhang, Ming; Huang, Yong; Shi, Le

    2015-04-01

    Cardiac hypertrophy is a primary pathological change associated with cardiovascular diseases. Dysregulated microRNAs are frequent in cardiovascular diseases and contribute to cardiac hypertrophy by regulating a series of targeted genes. In this study, a rat model of cardiac hypertrophy was created by transverse abdominal aortic constriction, and cardiomyocyte hypertrophy in cultured neonatal rat cardiomyocytes was induced using angiotensin II (AngII) to investigate the role of miR-101 in myocardial hypertrophy. We demonstrated that miR-101 was downregulated in both the transverse abdominal aortic constriction rat model and hypertrophic cardiac myocytes. The overexpression of miR-101 in neonatal rat cardiomyocytes, which was accompanied by a reduced Rab1a level, inhibits 3 cardinal features of cardiomyocyte hypertrophy: fetal gene expression, protein synthesis, and cell enlargement. Conversely, the downregulation of miR-101 reverses these effects. Furthermore, the luciferase reporter system demonstrated that Rab1a is a target gene of miR-101, and the ectopic expression of Rab1a can reverse the cardiomyocyte hypertrophy inhibitory activity of miR-101. Taken together, our findings identify miR-101 as an important regulator in cardiac hypertrophy and implicate the potential application of miR-101 in the therapy of cardiac hypertrophy.

  11. Physiology: postprandial cardiac hypertrophy in pythons.

    PubMed

    Andersen, Johnnie B; Rourke, Bryan C; Caiozzo, Vincent J; Bennett, Albert F; Hicks, James W

    2005-03-03

    Oxygen consumption by carnivorous reptiles increases enormously after they have eaten a large meal in order to meet metabolic demands, and this places an extra load on the cardiovascular system. Here we show that there is an extraordinarily rapid 40% increase in ventricular muscle mass in Burmese pythons (Python molurus) a mere 48 hours after feeding, which results from increased gene expression of muscle-contractile proteins. As this fully reversible hypertrophy occurs naturally, it could provide a useful model for investigating the mechanisms that lead to cardiac growth in other animals.

  12. Copper inhibition of hydrogen peroxide-induced hypertrophy in embryonic rat cardiac H9c2 cells.

    PubMed

    Zhou, Yang; Jiang, Youchun; Kang, Y James

    2007-03-01

    Previous studies have shown that dietary copper deficiency causes cardiac hypertrophy and depression of vascular epithelial growth factor (VEGF) expression in mouse model. Copper replenishment in the diet reverses cardiac hypertrophy and restores VEGF expression. The present study was undertaken to specifically determine the role of VEGF in copper effect on cell hypertrophy. Embryonic rat cardiac H9c2 cells were exposed to hydrogen peroxide to develop hypertrophy, determined by increases in cell size and total protein content. Copper addition at 5 microM in cultures suppressed cell hypertrophy. In the presence of anti-VEGF antibody, copper inhibitory effect on cell hypertrophy was blunted, and VEGF alone mimicked the inhibitory effect of copper. The results thus demonstrated that VEGF is critically involved in copper inhibition of cell hypertrophy induced by hydrogen peroxide in the H9c2 cells.

  13. Hepatocyte transplantation in children with liver cell failure

    PubMed Central

    Hamooda, Mohamed

    2016-01-01

    Patients with hepatic failure and liver-based metabolic disorders require management which is both costly and complex. Hepatocyte transplantation has been very encouraging as an alternative to organ transplantation for liver disease treatment, and studies in rodents, show that transplants involving isolated liver cells can reverse hepatic failure, and correct various metabolic deficiencies of the liver. This 2016 review is based on a literature search using PubMed including original articles, reviews, cases and clinical guidelines. The search terms were “hepatocyte transplantation”, “liver transplantation”, “liver cell failure”, “metabolic liver disorders”, “orthotropic liver transplantation”, “hepatocytes” and “stem cell transplantation”. The goal of this review is to summarize the significance of hepatocyte transplantation, the sources of hepatocytes and the barriers of hepatocyte transplantation using a detailed review of literature. Our review shows that treatment of patients with liver disease by hepatocyte transplantation has expanded exponentially, especially for patients suffering from liver-based metabolic disorders. Once hepatocyte transplantation has been shown to effectively replace organ transplantation for a portion of patients with life-threatening liver metabolic diseases and those with liver failure it will make cell therapy effective and available for a broad population of patients with liver disorders. PMID:27957309

  14. Redox regulation of cardiac hypertrophy.

    PubMed

    Sag, Can M; Santos, Celio X C; Shah, Ajay M

    2014-08-01

    It is increasingly evident that redox-dependent modifications in cellular proteins and signaling pathways (or redox signaling) play important roles in many aspects of cardiac hypertrophy. Indeed, these redox modifications may be intricately linked with the process of hypertrophy wherein there is not only a significant increase in myocardial O2 consumption but also important alterations in metabolic processes and in the local generation of O2-derived reactive species (ROS) that modulate and/or amplify cell signaling pathways. This article reviews our current knowledge of redox signaling pathways and their roles in cardiac hypertrophy. This article is part of a Special Issue entitled "Redox Signalling in the Cardiovascular System".

  15. Hypertension, hypertrophy, and reperfusion injury.

    PubMed

    Pagliaro, Pasquale; Penna, Claudia

    2017-03-01

    The heart of patients with hypertension and cardiac hypertrophy is more vulnerable to ischemia-reperfusion injury (IRI). Here we discuss the main mechanisms of IRI and possible targets for cardioprotection. In particular, we consider the viewpoint that hypertension and cardiac hypertrophy may act synergistically in increasing the predisposition to cardiovascular accidents and in worsening IRI. There is no doubt that hypertrophic hearts may be redirected to be less vulnerable to IRI. Some experimental evidences suggest that antihypertensive drugs may have beneficial effects, some of which are not directly related to hypertension-lowering effect. However, more thorough experimental and clinical studies are necessary to understand the mechanisms and to maximize the beneficial effects of reperfusion after a heart attack in the presence of comorbidities, such as hypertension and cardiac hypertrophy.

  16. Hepatocyte growth factor: a regenerative drug for acute hepatitis and liver cirrhosis.

    PubMed

    Mizuno, Shinya; Nakamura, Toshikazu

    2007-03-01

    Liver cirrhosis is a major cause of morbidity worldwide and is characterized by the loss of hepatocytes with interstitial fibrosis. In this review, we discuss the potential uses of hepatocyte growth factor for treating hepatic diseases, focusing on the molecular mechanisms whereby hepatocyte growth factor reverses liver cirrhosis. Hepatic myofibroblasts play a central role in the development of liver cirrhosis, while myofibroblasts acquire c-Met. Using a rat model of liver cirrhosis, we recently delineated the direct effect of hepatocyte growth factor toward myofibroblasts: the induction of apoptotic cell death associated with matrix degradation, the inhibition of overproliferation and the suppression of transforming growth factor-beta1 production in myofibroblasts. Hepatocyte growth factor elicits mitogenic, anti-apoptotic and anti-inflammatory functions in hepatocytes, therefore contributing to reversing liver dysfunction. Considering the insufficient production of hepatocyte growth factor is responsible for the manifestation of chronic hepatitis, supplementation with or reinduction of hepatocyte growth factor represents a new strategy for attenuating intractable liver diseases.

  17. Compensatory Hypertrophy of Skeletal Muscle: Contractile Characteristics

    ERIC Educational Resources Information Center

    Ianuzzo, C. D.; Chen, V.

    1977-01-01

    Describes an experiment using rats that demonstrates contractile characteristics of normal and hypertrophied muscle. Compensatory hypertrophy of the plantaris muscle is induced by surgical removal of the synergistic gastrocnemium muscle. Includes methods for determination of contractile properties of normal and hypertrophied muscle and…

  18. Glucose metabolism and cardiac hypertrophy

    PubMed Central

    Kolwicz, Stephen C.; Tian, Rong

    2011-01-01

    The most notable change in the metabolic profile of hypertrophied hearts is an increased reliance on glucose with an overall reduced oxidative metabolism, i.e. a reappearance of the foetal metabolic pattern. In animal models, this change is attributed to the down-regulation of the transcriptional cascades promoting gene expression for fatty acid oxidation and mitochondrial oxidative phosphorylation in adult hearts. Impaired myocardial energetics in cardiac hypertrophy also triggers AMP-activated protein kinase (AMPK), leading to increased glucose uptake and glycolysis. Aside from increased reliance on glucose as an energy source, changes in other glucose metabolism pathways, e.g. the pentose phosphate pathway, the glucosamine biosynthesis pathway, and anaplerosis, are also noted in the hypertrophied hearts. Studies using transgenic mouse models and pharmacological compounds to mimic or counter the switch of substrate preference in cardiac hypertrophy have demonstrated that increased glucose metabolism in adult heart is not harmful and can be beneficial when it provides sufficient fuel for oxidative metabolism. However, improvement in the oxidative capacity and efficiency rather than the selection of the substrate is likely the ultimate goal for metabolic therapies. PMID:21502371

  19. Cardiomyocyte Hypertrophy in Arrhythmogenic Cardiomyopathy.

    PubMed

    Gerçek, Mustafa; Gerçek, Muhammed; Kant, Sebastian; Simsekyilmaz, Sakine; Kassner, Astrid; Milting, Hendrik; Liehn, Elisa A; Leube, Rudolf E; Krusche, Claudia A

    2017-04-01

    Arrhythmogenic cardiomyopathy (AC) is a hereditary disease leading to sudden cardiac death or heart failure. AC pathology is characterized by cardiomyocyte loss and replacement fibrosis. Our goal was to determine whether cardiomyocytes respond to AC progression by pathological hypertrophy. To this end, we examined tissue samples from AC patients with end-stage heart failure and tissue samples that were collected at different disease stages from desmoglein 2-mutant mice, a well characterized AC model. We find that cardiomyocyte diameters are significantly increased in right ventricles of AC patients. Increased mRNA expression of the cardiac stress marker natriuretic peptide B is also observed in the right ventricle of AC patients. Elevated myosin heavy chain 7 mRNA expression is detected in left ventricles. In desmoglein 2-mutant mice, cardiomyocyte diameters are normal during the concealed disease phase but increase significantly after acute disease onset on cardiomyocyte death and fibrotic myocardial remodeling. Hypertrophy progresses further during the chronic disease stage. In parallel, mRNA expression of myosin heavy chain 7 and natriuretic peptide B is up-regulated in both ventricles with right ventricular preference. Calcineurin/nuclear factor of activated T cells (Nfat) signaling, which is linked to pathological hypertrophy, is observed during AC progression, as evidenced by Nfatc2 and Nfatc3 mRNA in cardiomyocytes and increased mRNA of the Nfat target regulator of calcineurin 1. Taken together, we demonstrate that pathological hypertrophy occurs in AC and is secondary to cardiomyocyte loss and cardiac remodeling.

  20. The ploidy conveyor of mature hepatocytes as a source of genetic variation.

    PubMed

    Duncan, Andrew W; Taylor, Matthew H; Hickey, Raymond D; Hanlon Newell, Amy E; Lenzi, Michelle L; Olson, Susan B; Finegold, Milton J; Grompe, Markus

    2010-10-07

    Mononucleated and binucleated polyploid hepatocytes (4n, 8n, 16n and higher) are found in all mammalian species, but the functional significance of this conserved phenomenon remains unknown. Polyploidization occurs through failed cytokinesis, begins at weaning in rodents and increases with age. Previously, we demonstrated that the opposite event, ploidy reversal, also occurs in polyploid hepatocytes generated by artificial cell fusion. This raised the possibility that somatic 'reductive mitoses' can also happen in normal hepatocytes. Here we show that multipolar mitotic spindles form frequently in mouse polyploid hepatocytes and can result in one-step ploidy reversal to generate offspring with halved chromosome content. Proliferating hepatocytes produce a highly diverse population of daughter cells with multiple numerical chromosome imbalances as well as uniparental origins. Our findings support a dynamic model of hepatocyte polyploidization, ploidy reversal and aneuploidy, a phenomenon that we term the 'ploidy conveyor'. We propose that this mechanism evolved to generate genetic diversity and permits adaptation of hepatocytes to xenobiotic or nutritional injury.

  1. Current status of hepatocyte xenotransplantation.

    PubMed

    Meier, Raphael P H; Navarro-Alvarez, Nalu; Morel, Philippe; Schuurman, Henk-Jan; Strom, Stephen; Bühler, Leo H

    2015-11-01

    The treatment of acute liver failure, a condition with high mortality, comprises optimal clinical care, and in severe cases liver transplantation. However, there are limitations in availability of organ donors. Hepatocyte transplantation is a promising alternative that could fill the medical need, in particular as the bridge to liver transplantation. Encapsulated porcine hepatocytes represent an unlimited source that could function as a bioreactor requiring minimal immunosuppression. Besides patients with acute liver failure, patients with alcoholic hepatitis who are unresponsive to a short course of corticosteroids are a target for hepatocyte transplantation. In this review we present an overview of the innate immune barriers in hepatocyte xenotransplantation, including the role of complement and natural antibodies; the role of phagocytic cells and ligands like CD47 in the regulation of phagocytic cells; and the role of Natural Killer cells. We present also some illustrations of physiological species incompatibilities in hepatocyte xenotransplantation, such as incompatibilities in the coagulation system. An overview of the methodology for cell microencapsulation is presented, followed by proof-of-concept studies in rodent and nonhuman primate models of fulminant liver failure: these studies document the efficacy of microencapsulated porcine hepatocytes which warrants progress towards clinical application. Lastly, we present an outline of a provisional clinical trial, that upon completion of preclinical work could start within the upcoming 2-3 years.

  2. Toxin-Induced Activation of Rat Hepatocyte Prostaglandin Synthesis and Phospholipid Metabolism

    DTIC Science & Technology

    1989-12-22

    SUBJECT TERMS (Continue on reverse if necesay and identify by block number) FIELD GROUP SUB-GROUP - microcystin -LR, arachidonic acid, phospholipid...pool was reduced to 47% (p ɘ.025) by l’ 3’ microcystin -LR. Changes in phospholipid classes indicated that prostaglandin formation induced by microcystin ... microcystin -LR has important effects on the regulation of inflammatory mediator synthesis in hepatocytes. 7.,1 ,- TOXIN-INDUCED ACTIVATION OF RAT HEPATOCYTE

  3. Mitochondria in cardiac hypertrophy and heart failure

    PubMed Central

    Rosca, Mariana G.; Tandler, Bernard; Hoppel, Charles L.

    2013-01-01

    Heart failure (HF) frequently is the unfavorable outcome of pathological heart hypertrophy. In contrast to physiological cardiac hypertrophy, which occurs in response to exercise and leads to full adaptation of contractility to the increased wall stress, pathological hypertrophy occurs in response to volume or pressure overload, ultimately leading to contractile dysfunction and HF. Because cardiac hypertrophy impairs the relationship between ATP demand and production, mitochondrial bioenergetics must keep up with the cardiac hypertrophic phenotype. We review data regarding the mitochondrial proteomic and energetic remodeling in cardiac hypertrophy, as well as the temporal and causal relationship between mitochondrial failure to match the increased energy demand and progression to cardiac decompensation. We suggest that the maladaptive effect of sustained neuroendocrine signals on mitochondria leads to bioenergetic fading which contributes to the progression from cardiac hypertrophy to failure. PMID:22982369

  4. Association between miR-181b and PKG 1 in myocardial hypertrophy and its clinical implications.

    PubMed

    Zhong, Wei; Yang, Jun; Cao, Qian; Huan, Xiaodong

    2015-09-01

    The aim of this study was to explore the microRNA (miR)-181b expression in myocardial hypertrophy and to investigate its association with cGMP-dependent protein kinase type I (PKG 1) in an in vitro model. The miR-181b level in the peripheral blood was determined in patients with myocardial hypertrophy, and an in vitro model was established via phenylephrine (PE) treatment. Reverse transcription-quantitative polymerase chain reaction analysis and western blotting were performed to detect the expression levels of miR-181b, PKG 1 and hypertrophy-related genes. The results revealed that the expression of miR-181b was elevated in the peripheral blood of patients with myocardial hypertrophy, and this may have contributed to the pathology and progression of the disease. When the primary myocardial cells were treated with PE, microscopic observation and flow cytometry revealed significant hypertrophy. Furthermore, upregulation of myocardial hypertrophy-related genes, including β-myosin heavy chain, α-sarcomeric actinin and atrial natriuretic peptide, was observed. The miR-181b expression level in the PE-treated cells was elevated, while the mRNA and protein expression levels of PKG 1 were decreased, indicating a negative correlation between miR-181b and PKG 1 in myocardial hypertrophy. In addition, when the PE-treated primary myocardial cells were transfected with miR-181b inhibitor, the reduced PKG 1 expression was restored and the myocardial hypertrophy alleviated, as indicated by the reduced cellular sizes and decreased expression levels of the myocardial hypertrophy-related genes. In conclusion, miR-181b expression has been shown to be upregulated in myocardial hypertrophy, and this may play a role in the pathogenesis of the disease by regulating the expression of PKG 1. The present findings suggest that miR-181b is a promising molecular indicator for the clinical diagnosis and treatment of cardiac hypertrophy.

  5. Three Dimensional Primary Hepatocyte Culture

    NASA Technical Reports Server (NTRS)

    Yoffe, Boris

    1998-01-01

    Our results demonstrated for the first time the feasibility of culturing PHH in microgravity bioreactors that exceeded the longest period obtained using other methods. Within the first week of culture, isolated hepatocytes started to form aggregates, which continuously increased in size (up to 1 cm) and macroscopically appeared as a multidimensional tissue-like assembly. To improve oxygenation and nutrition within the spheroids we performed experiments with the biodegradable nonwoven fiber-based polymers made from PolyGlycolic Acid (PGA). It has been shown that PGA scaffolds stimulate isolated cells to regenerate tissue with defined sizes and shapes and are currently being studied for various tissue-engineering applications. Our data demonstrated that culturing hepatocytes in the presence of PGA scaffolds resulted in more efficient cell assembly and formations of larger cell spheroids (up to 3 cm in length, see figure). The histology of cell aggregates cultured with PGA showed polymer fibers with attached hepatocytes. We initiated experiments to co-culture primary human hepatocytes with human microvascular endothelial cells in the bioreactor. The presence of endothelial cells in co-cultures were established by immunohistochemistry using anti-CD34 monoclonal Ab. Our preliminary data demonstrated that cultures of purified hepatocytes with human microvascular endothelial cells exhibited better growth and expressed higher levels of albumin MRNA for a longer period of time than cultures of ppfified, primary human hepatocytes cultured alone. We also evaluated microsomal deethylation activity of hepatocytes cultured in the presence of endothelial cells.In summary, we have established liver cell culture, which mimicked the structure and function of the parent tissue.

  6. Marked left ventricular hypertrophy mimicking hypertrophic cardiomyopathy associated with steroid therapy for congenital adrenal hyperplasia.

    PubMed

    Scirè, Giuseppe; D'Anella, Giorgio; Cristofori, Laura; Mazzuca, Valentina; Cianfarani, Stefano

    2007-06-01

    We describe a child treated with high-dose steroid therapy for congenital adrenal hyperplasia who showed marked left ventricular hypertrophy mimicking hypertrophic cardiomyopathy associated with steroid therapy for congenital adrenal hyperplasia. Cardiomyopathy reversed completely when an appropriate steroid therapeutic regimen was established.

  7. Genetics Home Reference: myostatin-related muscle hypertrophy

    MedlinePlus

    ... Conditions myostatin-related muscle hypertrophy myostatin-related muscle hypertrophy Enable Javascript to view the expand/collapse boxes. ... Open All Close All Description Myostatin-related muscle hypertrophy is a rare condition characterized by reduced body ...

  8. The current status of primary hepatocyte culture

    PubMed Central

    Mitaka, Toshihiro

    1998-01-01

    Recently, there have been significant advances toward the development of culture conditions that promote proliferation of primary rodent hepatocytes. There are two major methods for the multiplication of hepatocytes in vitro: one is the use of nicotinamide, the other is the use of a nutrient-rich medium. In the medium containing a high concentration of nicotinamide and a growth factor, primary hepatocytes can proliferate well. In this culture condition small mononucleate cells, which are named small hepatocytes, appear and form colonies. Small hepatocytes have a high potential to proliferate while maintaining hepatic characteristics, and can differentiate into mature ones. On the other hand, combining the nutrient-rich medium with 2% DMSO, the proliferated hepatocytes can recover the hepatic differentiated functions and maintain them for a long time. In this review I describe the culture conditions for the proliferation and differentiation of primary hepatocytes and discuss the small hepatocytes, especially their roles in liver growth. PMID:10319020

  9. Masseter and medial pterygoid muscle hypertrophy.

    PubMed

    Guruprasad, R; Rishi, Sudhirkumar; Nair, Preeti P; Thomas, Shaji

    2011-09-26

    Hypertrophy refers to an enlargement caused by an increase in the size but not in the number of cells. Generalised masticatory muscle hypertrophy may affect the temporalis muscle, masseters and medial pterygoids in a variety of combinations. Masseteric hypertrophy may present as either unilateral or bilateral painless swelling of unknown origin in the region of angle of mandible. It is a relatively rare condition and presents a diagnostic dilemma. While the history and clinical examination are important in differentiating this benign condition from parotid or dental pathology, they cannot necessarily exclude rare malignant lesion within the muscle. Advanced imaging modalities like CT and MRI are essential to confirm the diagnosis. Here the authors are reporting a unique case of masseter muscle hypertrophy along with medial pterygoid hypertrophy which was missed clinically but confirmed using CT and MRI.

  10. Kidney glycosphingolipids are elevated early in diabetic nephropathy and mediate hypertrophy of mesangial cells

    PubMed Central

    Subathra, Marimuthu; Korrapati, Midhun; Howell, Lauren A.; Arthur, John M.; Shayman, James A.; Schnellmann, Rick G.

    2015-01-01

    Glycosphingolipids (GSLs) play a role in insulin resistance and diabetes, but their role in diabetic nephropathy (DN) has received limited attention. We used 9- and 17-wk-old nondiabetic db/m and diabetic db/db mice to examine the role of GSLs in DN. Cerebrosides or monoglycosylated GSLs [hexosylceramides (HexCers); glucosyl- and galactosylceramides] and lactosylceramide (LacCers) were elevated in db/db mouse kidney cortices, specifically in glomeruli, and also in urine. In our recent paper (25), we observed that the kidneys exhibited glomerular hypertrophy and proximal tubular vacuolization and increased fibrosis markers at these time points. Mesangial cells contribute to hyperglycemia-induced glomerular hypertrophy in DN. Hyperglycemic culture conditions, similar to that present in diabetes, were sufficient to elevate mesangial cell HexCers and increase markers of fibrosis, extracellular matrix proteins, and cellular hypertrophy. Inhibition of glucosylceramide synthase or lowering glucose levels decreased markers of fibrosis and extracellular matrix proteins and reversed mesangial cell hypertrophy. Hyperglycemia increased phosphorylated (p)SMAD3 and pAkt levels and reduced phosphatase and tensin homolog levels, which were reversed with glucosylceramide synthase inhibition. These data suggest that inhibition of glucosylceramide synthase reversed mesangial cell hypertrophy through decreased pAkt and pSmad3 and increased pathways responsible for protein degradation. Importantly, urinary GSL levels were higher in patients with DN compared with healthy control subjects, implicating a role for these lipids in human DN. Thus, hyperglycemia in type II diabetes leads to renal dysfunction at least in part by inducing accumulation of HexCers and LacCers in mesangial cells, resulting in fibrosis, extracellular matrix production, and hypertrophy. PMID:26041445

  11. Efficient amelioration of carbon tetrachloride induced toxicity in isolated rat hepatocytes by Syzygium cumini Skeels extract.

    PubMed

    Veigas, Jyothi M; Shrivasthava, Richa; Neelwarne, Bhagyalakshmi

    2008-09-01

    Syzygium cumini, Indian black plum or Java plum, is a rich source for anthocyanins (230 mg/100g DW) showing high antioxidant activity in vitro. In the following study it is further demonstrated that S. cumini peel extract rich in anthocyanins (SCA) offers considerable protection against carbon tetrachloride (CCl(4))-induced damage in rat hepatocytes. SCA itself being non-toxic to primary rat hepatocytes at concentrations ranging from 50 to 500 ppm, was found to suppress CCl(4)-induced LDH leakage by 54% at 50ppm, thereby improving the cell viability by 39%. The SCA significantly reversed the CCl(4) induced changes in cellular glutathione (GSH) level, lipid peroxidation and activity of the antioxidant enzyme glutathione peroxidase. Exposure of hepatocytes to SCA after CCl(4) treatment was found to elevate GSH and GPx activities by 2-folds, whereas the activities of catalase and superoxide dismutase were not significantly affected. The fruit pulp extract (SPE) was less effective in offering protection to rat hepatocytes, particularly in terms of total GSH content and a consequent increase in lipid peroxidation although the higher GPx activity suggests the probable involvement of GSH as a substrate for GPx. These observations suggest that the fruit peel extract of S. cumini, is largely responsible for the reversal of CCl(4)-induced oxidative damage in rat hepatocytes. Both peel and pulp extract appear to offer protection to rat hepatocytes through GPx along with other biological pathways independent of catalase and superoxide dismutase.

  12. Electrochemical sensing of hepatocyte viability.

    PubMed

    Tsai, Hweiyan; Tsai, Shang-heng; Ting, Wei-Jen; Hu, Chao-Chin; Fuh, C Bor

    2014-05-21

    We investigated the use of amperometric and chronoamperometric methods with a double mediator system and screen-printed electrodes (SPEs) for the electrochemical sensing of hepatocyte viability. Cell counts were determined based on measuring cellular respiration via interaction of electroactive redox mediators. The oxidation currents of chronoamperometric measurement were proportional to the concentrations of ferrocyanide which was produced via interaction of cellular respiration, succinate and ferricyanide. The integrated oxidation charges increased linearly with the density of the cultured primary rat hepatocytes over a range of 1 × 10(5) to 5 × 10(5) cells per well (slope = 1.98 (±0.08) μC per 10(5) cells; R(2) = 0.9969), and the detection limit was 7600 (±300) cells per well based on S/N = 3. Each density of cells was cultured in triple replicates and individual cell samples were evaluated. The results of the cytotoxic effect of the chronoamperometric method are comparable to those of the tetrazolium-based colorimetric assay. The chronoamperometric method with ferricyanide and succinate mediators is an efficient, alternative method for assessing the viability of primary hepatocytes which can be completed in 20 min. Succinate did not provide an efficient electron shuttle between cytosolic respiratory redox activity of cancer cells and extracellular ferricyanide, an effect that may be useful for distinguishing hepatocarcinoma cells from healthy hepatocytes.

  13. AAEM minimonograph #46: neurogenic muscle hypertrophy.

    PubMed

    Gutmann, L

    1996-07-01

    Muscle hypertrophy occurs uncommonly in several neurogenic disorders including neuropathies, radiculopathies, spinal muscular atrophy, and post-polio syndrome. Its pathogenesis varies in different circumstances. In the presence of generalized myokymia and neuromyotonia (Isaacs' syndrome), symmetrical hypertrophy appears to be the result of continuous spontaneous electrical stimulation of myofibers and, in some cases, results in type 1 myofiber preponderance. Focal hypertrophy occurring with radiculopathies and mononeuropathies was associated with complex repetitive discharges (CRDs) in approximately half the cases. CRDs may play a role in the pathogenesis of myofiber hypertrophy by continuous myofiber stimulation, but in some cases, with and without CRDs, myofiber hypertrophy may be related to mechanical events. Muscle enlargement seen in old polio appears to involve a significant degree of pseudohypertrophy, although some myofiber hypertrophy occurs. The symmetrical occurrence of hypertrophy in genetically determined disorders, such as spinal muscular atrophy, and hereditary motor and sensory neuropathy types 1 and 2 may have both a genetic and a mechanical basis in addition to pseudohypertrophy in some cases.

  14. Regression of altitude-produced cardiac hypertrophy.

    NASA Technical Reports Server (NTRS)

    Sizemore, D. A.; Mcintyre, T. W.; Van Liere, E. J.; Wilson , M. F.

    1973-01-01

    The rate of regression of cardiac hypertrophy with time has been determined in adult male albino rats. The hypertrophy was induced by intermittent exposure to simulated high altitude. The percentage hypertrophy was much greater (46%) in the right ventricle than in the left (16%). The regression could be adequately fitted to a single exponential function with a half-time of 6.73 plus or minus 0.71 days (90% CI). There was no significant difference in the rates of regression for the two ventricles.

  15. Sub-lethal concentration of arsenic interferes with the proliferation of hepatocytes and induces in vivo apoptosis in Clarias batrachus L.

    PubMed

    Datta, Soma; Saha, Dhira Rani; Ghosh, Debabrata; Majumdar, Tanmay; Bhattacharya, Shelley; Mazumder, Shibnath

    2007-04-01

    We studied the hepatocellular alterations induced by sub-lethal concentrations (0.50 muM) of arsenic in Indian catfish Clarias batrachus L. Sub-lethal arsenic exposure altered serum aspartate aminotransferase and alkaline phosphatase levels and brought about significant changes in different serum biochemical parameters. Arsenic exposure reduced total hepatocyte protein content and suppressed the proliferation of hepatocytes in a time-dependent manner. Routine histological studies on liver documented arsenic-induced changes characterized by dilated sinusoids, formation of intracellular edema, megalocytosis, vacuolation and appearance of hepatic cells with distorted nuclei. Transmission electron microscopy of hepatocytes further revealed hyperplasia and hypertrophy of mitochondria, development of dilated rough endoplasmic reticulum and changes in peroxisome size with duration of arsenic exposure. Degeneration of mitochondrial cristae and condensation of chromatin was also evident in arsenic-exposed hepatocytes. A significant number of hepatocytes isolated from arsenic-exposed fish stained with annexin V and demonstrated DNA ladder characteristic of apoptosis. Single-cell gel electrophoresis of exposed hepatocytes also revealed the development of comets usually seen in apoptotic cells. Using specific inhibitors it was determined that the arsenic-induced apoptosis of hepatocytes was caspase-mediated, involving the caspase 3 pathway.

  16. Adaptive parotid gland hypertrophy induced by dietary treatment of GSE in rats.

    PubMed

    Inoue, Kaoru; Morikawa, Tomomi; Matsuo, Saori; Tamura, Kei; Takahashi, Miwa; Yoshida, Midori

    2014-08-01

    In a 13-week feeding toxicity study of grape skin extract (GSE) performed previously, 5.0% GSE showed diffuse hypertrophy and basophilia in rat parotid glands. To clarify whether the change in the parotid glands was an adverse effect of GSE, 6-week-old male F344 rats were fed a diet containing 5.0% GSE or were administered a dose corresponding to the dietary concentration via gavage for 4 weeks, and the treatment was stopped for 2 weeks. To ascertain the effect of astringency, other animals were fed a diet containing 5.0% tannic acid (TA) using the same protocol as the GSE feed group. Control groups were fed a basal diet or were administered sterilized distilled water by gavage. In the GSE and TA feed groups, diffuse severe hypertrophy and basophilia in the parotid glandular epithelial cells were observed. Macroscopic, microscopic, and ultrastructural characteristics consistent with cellular hypertrophy was less apparent after the recovery period in both feed groups. In contrast, no changes were observed in the parotid glands of the gavage GSE and control groups at week 4. Based on these findings of parotid hypertrophy without cytotoxicity, the data from this and previous studies suggest that hypertrophy of the parotid glands induced by feeding treatment with GSE is an adaptive non-adverse effect that is reversible upon removal of the sialotrophic agent.

  17. Reduction of blood oxygen levels enhances postprandial cardiac hypertrophy in Burmese python (Python bivittatus).

    PubMed

    Slay, Christopher E; Enok, Sanne; Hicks, James W; Wang, Tobias

    2014-05-15

    Physiological cardiac hypertrophy is characterized by reversible enlargement of cardiomyocytes and changes in chamber architecture, which increase stroke volume and via augmented convective oxygen transport. Cardiac hypertrophy is known to occur in response to repeated elevations of O2 demand and/or reduced O2 supply in several species of vertebrate ectotherms, including postprandial Burmese pythons (Python bivittatus). Recent data suggest postprandial cardiac hypertrophy in P. bivittatus is a facultative rather than obligatory response to digestion, though the triggers of this response are unknown. Here, we hypothesized that an O2 supply-demand mismatch stimulates postprandial cardiac enlargement in Burmese pythons. To test this hypothesis, we rendered animals anemic prior to feeding, essentially halving blood oxygen content during the postprandial period. Fed anemic animals had heart rates 126% higher than those of fasted controls, which, coupled with a 71% increase in mean arterial pressure, suggests fed anemic animals were experiencing significantly elevated cardiac work. We found significant cardiac hypertrophy in fed anemic animals, which exhibited ventricles 39% larger than those of fasted controls and 28% larger than in fed controls. These findings support our hypothesis that those animals with a greater magnitude of O2 supply-demand mismatch exhibit the largest hearts. The 'low O2 signal' stimulating postprandial cardiac hypertrophy is likely mediated by elevated ventricular wall stress associated with postprandial hemodynamics.

  18. Hepatocytes Determine the Hypoxic Microenvironment and Radiosensitivity of Colorectal Cancer Cells Through Production of Nitric Oxide That Targets Mitochondrial Respiration

    SciTech Connect

    Jiang, Heng; Verovski, Valeri N.; Leonard, Wim; Law, Ka Lun; Vermeersch, Marieke; Storme, Guy; Van den Berge, Dirk; Gevaert, Thierry; Sermeus, Alexandra; De Ridder, Mark

    2013-03-01

    Purpose: To determine whether host hepatocytes may reverse hypoxic radioresistance through nitric oxide (NO)-induced oxygen sparing, in a model relevant to colorectal cancer (CRC) liver metastases. Methods and Materials: Hepatocytes and a panel of CRC cells were incubated in a tissue-mimetic coculture system with diffusion-limited oxygenation, and oxygen levels were monitored by an oxygen-sensing fluorescence probe. To activate endogenous NO production, cocultures were exposed to a cytokine mixture, and the expression of inducible nitric oxide synthase was analyzed by reverse transcription–polymerase chain reaction, Western blotting, and NO/nitrite production. The mitochondrial targets of NO were examined by enzymatic activity. To assess hypoxic radioresponse, cocultures were irradiated and reseeded for colonies. Results: Resting hepatocytes consumed 10-40 times more oxygen than mouse CT26 and human DLD-1, HT29, HCT116, and SW480 CRC cells, and thus seemed to be the major effectors of hypoxic conditioning. As a result, hepatocytes caused uniform radioprotection of tumor cells at a 1:1 ratio. Conversely, NO-producing hepatocytes radiosensitized all CRC cell lines more than 1.5-fold, similar to the effect of selective mitochondrial inhibitors. The radiosensitizing effect was associated with a respiratory self-arrest of hepatocytes at the level of aconitase and complex II, which resulted in profound reoxygenation of tumor cells through oxygen sparing. Nitric oxide–producing hepatocytes were at least 10 times more active than NO-producing macrophages to reverse hypoxia-induced radioresistance. Conclusions: Hepatocytes were the major determinants of the hypoxic microenvironment and radioresponse of CRC cells in our model of metabolic hypoxia. We provide evidence that reoxygenation and radiosensitization of hypoxic CRC cells can be achieved through oxygen sparing induced by endogenous NO production in host hepatocytes.

  19. Functions of Autophagy in Pathological Cardiac Hypertrophy

    PubMed Central

    Li, Zhenhua; Wang, Jian; Yang, Xiao

    2015-01-01

    Pathological cardiac hypertrophy is the response of heart to various biomechanical and physiopathological stimuli, such as aging, myocardial ischemia and hypertension. However, a long-term exposure to the stress makes heart progress to heart failure. Autophagy is a dynamic self-degradative process necessary for the maintenance of cellular homeostasis. Accumulating evidence has revealed a tight link between cardiomyocyte autophagy and cardiac hypertrophy. Sophisticatedly regulated autophagy protects heart from various physiological and pathological stimuli by degradating and recycling of protein aggregates, lipid drops, or organelles. Here we review the recent progresses concerning the functions of autophagy in cardiac hypertrophy induced by various hypertrophic stimuli. Moreover, the therapeutic strategies targeting autophagy for cardiac hypertrophy will also be discussed. PMID:25999790

  20. Long-term administration of pyridostigmine attenuates pressure overload-induced cardiac hypertrophy by inhibiting calcineurin signalling.

    PubMed

    Lu, Yi; Zhao, Ming; Liu, Jin-Jun; He, Xi; Yu, Xiao-Jiang; Liu, Long-Zhu; Sun, Lei; Chen, Li-Na; Zang, Wei-Jin

    2017-03-10

    Cardiac hypertrophy is associated with autonomic imbalance, characterized by enhanced sympathetic activity and withdrawal of parasympathetic control. Increased parasympathetic function improves ventricular performance. However, whether pyridostigmine, a reversible acetylcholinesterase inhibitor, can offset cardiac hypertrophy induced by pressure overload remains unclear. Hence, this study aimed to determine whether pyridostigmine can ameliorate pressure overload-induced cardiac hypertrophy and identify the underlying mechanisms. Rats were subjected to either sham or constriction of abdominal aorta surgery and treated with or without pyridostigmine for 8 weeks. Vagal activity and cardiac function were determined using PowerLab. Cardiac hypertrophy was evaluated using various histological stains. Protein markers for cardiac hypertrophy were quantitated by Western blot and immunoprecipitation. Pressure overload resulted in a marked reduction in vagal discharge and a profound increase in cardiac hypertrophy index and cardiac dysfunction. Pyridostigmine increased the acetylcholine levels by inhibiting acetylcholinesterase in rats with pressure overload. Pyridostigmine significantly attenuated cardiac hypertrophy based on reduction in left ventricular weight/body weight, suppression of the levels of atrial natriuretic peptide, brain natriuretic peptide and β-myosin heavy chain, and a reduction in cardiac fibrosis. These effects were accompanied by marked improvement of cardiac function. Additionally, pyridostigmine inhibited the CaN/NFAT3/GATA4 pathway and suppressed Orai1/STIM1 complex formation. In conclusion, pressure overload resulted in cardiac hypertrophy, cardiac dysfunction and a significant reduction in vagal discharge. Pyridostigmine attenuated cardiac hypertrophy and improved cardiac function, which was related to improved cholinergic transmission efficiency (decreased acetylcholinesterase and increased acetylcholine), inhibition of the CaN/NFAT3/GATA4

  1. Hepatocytes: critical for glucose homeostasis.

    PubMed

    Klover, Peter J; Mooney, Robert A

    2004-05-01

    Maintaining blood glucose levels within a narrow range is a critical physiological function requiring multiple metabolic pathways and involving several cell types, including a prominent role for hepatocytes. Under hormonal control, hepatocytes can respond to either feeding or fasting conditions by storing or producing glucose as necessary. In the fasting state, the effects of glucagon avoid hypoglycemia by stimulating glucogenesis and glycogenolysis and initiating hepatic glucose release. Postprandially, insulin prevents hyperglycemia, in part, by suppressing hepatic gluconeogenesis and glycogenolysis and facilitating hepatic glycogen synthesis. Both transcriptional regulation of rate limiting enzymes and modulation of enzyme activity through phosphorylation and allosteric regulation are involved. Type 2 diabetes mellitus is the most common serious metabolic condition in the world, and results from a subnormal response of tissues to insulin (insulin resistance) and a failure of the insulin-secreting beta cells to compensate. In type 2 diabetes, glucose is overproduced by the hepatocyte and is ineffectively metabolized by other organs. Impairments in the insulin signal transduction pathway appear to be critical lesions contributing to insulin resistance and type 2 diabetes.

  2. Mechanotransduction pathways in skeletal muscle hypertrophy.

    PubMed

    Yamada, André Katayama; Verlengia, Rozangela; Bueno Junior, Carlos Roberto

    2012-02-01

    In the last decade, molecular biology has contributed to define some of the cellular events that trigger skeletal muscle hypertrophy. Recent evidence shows that insulin like growth factor 1/phosphatidyl inositol 3-kinase/protein kinase B (IGF-1/PI3K/Akt) signaling is not the main pathway towards load-induced skeletal muscle hypertrophy. During load-induced skeletal muscle hypertrophy process, activation of mTORC1 does not require classical growth factor signaling. One potential mechanism that would activate mTORC1 is increased synthesis of phosphatidic acid (PA). Despite the huge progress in this field, it is still early to affirm which molecular event induces hypertrophy in response to mechanical overload. Until now, it seems that mTORC1 is the key regulator of load-induced skeletal muscle hypertrophy. On the other hand, how mTORC1 is activated by PA is unclear, and therefore these mechanisms have to be determined in the following years. The understanding of these molecular events may result in promising therapies for the treatment of muscle-wasting diseases. For now, the best approach is a good regime of resistance exercise training. The objective of this point-of-view paper is to highlight mechanotransduction events, with focus on the mechanisms of mTORC1 and PA activation, and the role of IGF-1 on hypertrophy process.

  3. DDiT4L promotes autophagy and inhibits pathological cardiac hypertrophy in response to stress.

    PubMed

    Simonson, Bridget; Subramanya, Vinita; Chan, Mun Chun; Zhang, Aifeng; Franchino, Hannabeth; Ottaviano, Filomena; Mishra, Manoj K; Knight, Ashley C; Hunt, Danielle; Ghiran, Ionita; Khurana, Tejvir S; Kontaridis, Maria I; Rosenzweig, Anthony; Das, Saumya

    2017-02-28

    Physiological cardiac hypertrophy, in response to stimuli such as exercise, is considered adaptive and beneficial. In contrast, pathological cardiac hypertrophy that arises in response to pathological stimuli such as unrestrained high blood pressure and oxidative or metabolic stress is maladaptive and may precede heart failure. We found that the transcript encoding DNA damage-inducible transcript 4-like (DDiT4L) was expressed in murine models of pathological cardiac hypertrophy but not in those of physiological cardiac hypertrophy. In cardiomyocytes, DDiT4L localized to early endosomes and promoted stress-induced autophagy through a process involving mechanistic target of rapamycin complex 1 (mTORC1). Exposing cardiomyocytes to various types of pathological stress increased the abundance of DDiT4L, which inhibited mTORC1 but activated mTORC2 signaling. Mice with conditional cardiac-specific overexpression of DDiT4L had mild systolic dysfunction, increased baseline autophagy, reduced mTORC1 activity, and increased mTORC2 activity, all of which were reversed by suppression of transgene expression. Genetic suppression of autophagy also reversed cardiac dysfunction in these mice. Our data showed that DDiT4L may be an important transducer of pathological stress to autophagy through mTOR signaling in the heart and that DDiT4L could be therapeutically targeted in cardiovascular diseases in which autophagy and mTOR signaling play a major role.

  4. Strategies for immortalization of primary hepatocytes

    PubMed Central

    Eva, Ramboer; Bram, De Craene; Joery, De Kock; Tamara, Vanhaecke; Geert, Berx; Vera, Rogiers; Mathieu, Vinken

    2014-01-01

    The liver has the unique capacity to regenerate in response to a damaging event. Liver regeneration is hereby largely driven by hepatocyte proliferation, which in turn relies on cell cycling. The hepatocyte cell cycle is a complex process that is tightly regulated by several well-established mechanisms. In vitro, isolated hepatocytes do not longer retain this proliferative capacity. However, in vitro cell growth can be boosted by immortalization of hepatocytes. Well-defined immortalization genes can be artificially overexpressed in hepatocytes or the cells can be conditionally immortalized leading to controlled cell proliferation. This paper discusses the current immortalization techniques and provides a state-of-the-art overview of the actually available immortalized hepatocyte-derived cell lines and their applications. PMID:24911463

  5. Palmitate Inhibits SIRT1-Dependent BMAL1/CLOCK Interaction and Disrupts Circadian Gene Oscillations in Hepatocytes

    PubMed Central

    Tong, Xin; Zhang, Deqiang; Arthurs, Blake; Li, Pei; Durudogan, Leigh; Gupta, Neil; Yin, Lei

    2015-01-01

    Elevated levels of serum saturated fatty acid palmitate have been shown to promote insulin resistance, increase cellular ROS production, and trigger cell apoptosis in hepatocytes during the development of obesity. However, it remains unclear whether palmitate directly impacts the circadian clock in hepatocytes, which coordinates nutritional inputs and hormonal signaling with downstream metabolic outputs. Here we presented evidence that the molecular clock is a novel target of palmitate in hepatocytes. Palmitate exposure at low dose inhibits the molecular clock activity and suppresses the cyclic expression of circadian targets including Dbp, Nr1d1 and Per2 in hepatocytes. Palmitate treatment does not seem to alter localization or reduce protein expression of BMAL1 and CLOCK, the two core components of the molecular clock in hepatocytes. Instead, palmitate destabilizes the protein-protein interaction between BMAL1-CLOCK in a dose and time-dependent manner. Furthermore, we showed that SIRT1 activators could reverse the inhibitory action of palmitate on BMAL1-CLOCK interaction and the clock gene expression, whereas inhibitors of NAD synthesis mimic the palmitate effects on the clock function. In summary, our findings demonstrated that palmitate inhibits the clock function by suppressing SIRT1 function in hepatocytes. PMID:26075729

  6. Postural control in women with breast hypertrophy

    PubMed Central

    Barbosa, Alessandra Ferreira; Raggi, Gabriela Cristina; dos Santos Cardoso Sá, Cristina; Costa, Márcio Paulino; de Lima, Jonas Eraldo; Tanaka, Clarice

    2012-01-01

    OBJECTIVES: The consequences of breast hypertrophy have been described based on the alteration of body mass distribution, leading to an impact on psychological and physical aspects. The principles of motor control suggest that breast hypertrophy can lead to sensorimotor alterations and the impairment of body balance due to postural misalignment. The aim of this study is to evaluate the postural control of women with breast hypertrophy under different sensory information conditions. METHOD: This cross-sectional study included 14 women with breast hypertrophy and 14 without breast hypertrophy, and the mean ages of the groups were 39±15 years and 39±16 years, respectively. A force platform was used to assess the sensory systems that contribute to postural control: somatosensory, visual and vestibular. Four postural conditions were sequentially tested: eyes open and fixed platform, eyes closed and fixed platform, eyes open and mobile platform, and eyes closed and mobile platform. The data were processed, and variables related to the center of pressure were analyzed for each condition. The Kruskal-Wallis test was used to compare the conditions between the groups for the area of center of pressure displacement and the velocity of center of pressure displacement in the anterior-posterior and medial-lateral directions. The alpha level error was set at 0.05. RESULTS: Women with breast hypertrophy presented an area that was significantly higher for three out of four conditions and a higher velocity of center of pressure displacement in the anterior-posterior direction under two conditions: eyes open and mobile platform and eyes closed and mobile platform. CONCLUSIONS: Women with breast hypertrophy have altered postural control, which was demonstrated by the higher area and velocity of center of pressure displacement. PMID:22892919

  7. Anabolic Steroid Reversal of Denervation Atrophy

    DTIC Science & Technology

    2012-03-01

    10-1-0932 TITLE: Anabolic Steroid Reversal of Denervation Atrophy PRINCIPAL INVESTIGATOR: Dr. Jonathan E. Isaacs...certainly “denervation atrophy” plays a significant role. Anabolic steroids , which have been shown to cause hypertrophy of muscle fibers, increase net...of satellite cells to muscle fibers. In conclusion, there did not seem to be a functional benefit for anabolic steroid treatment following

  8. MRI of nasopharyngeal adenoid hypertrophy.

    PubMed

    Surov, Alexey; Ryl, Ina; Bartel-Friedrich, Sylvia; Wienke, Andreas; Kösling, Sabrina

    2016-10-01

    Nasopharyngeal adenoid hypertrophy (NAH) is a typical benign lesion. Due to involution, nasopharyngeal lymphatic tissue usually is not found in adults beyond the 30th to 40th year of life. However, occasionally NAH has been recognized after the 50th or 60th year. The aim of this study is to identify the frequency of NAH and to analyze its MRI findings in different age groups. From 2007 to 2011, 6693 MR investigations of the head were performed at our institution. MRI was obtained with a 1.5 T MRI device. NAH was identified in 18.0% of the patients. The frequency of NAH varied from 60.3% to 1.0% in the different age groups. The mean size of NAH was 23.2 ± 4.5 mm in cranio-caudal, 31.1 ± 5.2 mm in left-right, and 14.2 ± 4.1 mm in the anterior-posterior direction. The left-right and cranio-caudal sizes of NAH were largest in the 0-9 age group and decreased with age. On T1-w images most lesions (95.4%) were hypointense in comparison to the adjacent musculature. On T2-w fat-saturated images 82.4% of the lesions were hyperintense. After intravenous administration of contrast medium most lesions showed a slight enhancement (58.6%). Moderate enhancement was seen in 32.4% and a marked enhancement was identified in 9.0%. In the 0-9 age group most lesions showed a slight enhancement. Cysts within NAH were identified in 433 cases (35.9%). The frequency of cysts increased continuously with age, namely from 10.9% to 65.2%.

  9. The paradox of muscle hypertrophy in muscular dystrophy.

    PubMed

    Kornegay, Joe N; Childers, Martin K; Bogan, Daniel J; Bogan, Janet R; Nghiem, Peter; Wang, Jiahui; Fan, Zheng; Howard, James F; Schatzberg, Scott J; Dow, Jennifer L; Grange, Robert W; Styner, Martin A; Hoffman, Eric P; Wagner, Kathryn R

    2012-02-01

    Mutations in the dystrophin gene cause Duchenne and Becker muscular dystrophy in humans and syndromes in mice, dogs, and cats. Affected humans and dogs have progressive disease that leads primarily to muscle atrophy. Mdx mice progress through an initial phase of muscle hypertrophy followed by atrophy. Cats have persistent muscle hypertrophy. Hypertrophy in humans has been attributed to deposition of fat and connective tissue (pseudohypertrophy). Increased muscle mass (true hypertrophy) has been documented in animal models. Muscle hypertrophy can exaggerate postural instability and joint contractures. Deleterious consequences of muscle hypertrophy should be considered when developing treatments for muscular dystrophy.

  10. Hepatocyte-specific deletion of hepatocyte nuclear factor-4α in adult mice results in increased hepatocyte proliferation.

    PubMed

    Walesky, Chad; Gunewardena, Sumedha; Terwilliger, Ernest F; Edwards, Genea; Borude, Prachi; Apte, Udayan

    2013-01-01

    Hepatocyte nuclear factor-4α (HNF4α) is known as the master regulator of hepatocyte differentiation. Recent studies indicate that HNF4α may inhibit hepatocyte proliferation via mechanisms that have yet to be identified. Using a HNF4α knockdown mouse model based on delivery of inducible Cre recombinase via an adeno-associated virus 8 viral vector, we investigated the role of HNF4α in the regulation of hepatocyte proliferation. Hepatocyte-specific deletion of HNF4α resulted in increased hepatocyte proliferation. Global gene expression analysis showed that a majority of the downregulated genes were previously known HNF4α target genes involved in hepatic differentiation. Interestingly, ≥500 upregulated genes were associated with cell proliferation and cancer. Furthermore, we identified potential negative target genes of HNF4α, many of which are involved in the stimulation of proliferation. Using chromatin immunoprecipitation analysis, we confirmed binding of HNF4α at three of these genes. Furthermore, overexpression of HNF4α in mouse hepatocellular carcinoma cells resulted in a decrease in promitogenic gene expression and cell cycle arrest. Taken together, these data indicate that, apart from its role in hepatocyte differentiation, HNF4α actively inhibits hepatocyte proliferation by repression of specific promitogenic genes.

  11. Hepatocyte-specific deletion of hepatocyte nuclear factor-4α in adult mice results in increased hepatocyte proliferation

    PubMed Central

    Walesky, Chad; Gunewardena, Sumedha; Terwilliger, Ernest F.; Edwards, Genea; Borude, Prachi

    2013-01-01

    Hepatocyte nuclear factor-4α (HNF4α) is known as the master regulator of hepatocyte differentiation. Recent studies indicate that HNF4α may inhibit hepatocyte proliferation via mechanisms that have yet to be identified. Using a HNF4α knockdown mouse model based on delivery of inducible Cre recombinase via an adeno-associated virus 8 viral vector, we investigated the role of HNF4α in the regulation of hepatocyte proliferation. Hepatocyte-specific deletion of HNF4α resulted in increased hepatocyte proliferation. Global gene expression analysis showed that a majority of the downregulated genes were previously known HNF4α target genes involved in hepatic differentiation. Interestingly, ≥500 upregulated genes were associated with cell proliferation and cancer. Furthermore, we identified potential negative target genes of HNF4α, many of which are involved in the stimulation of proliferation. Using chromatin immunoprecipitation analysis, we confirmed binding of HNF4α at three of these genes. Furthermore, overexpression of HNF4α in mouse hepatocellular carcinoma cells resulted in a decrease in promitogenic gene expression and cell cycle arrest. Taken together, these data indicate that, apart from its role in hepatocyte differentiation, HNF4α actively inhibits hepatocyte proliferation by repression of specific promitogenic genes. PMID:23104559

  12. Na+/H+ exchanger isoform 1 induced cardiomyocyte hypertrophy involves activation of p90 ribosomal s6 kinase.

    PubMed

    Jaballah, Maiy; Mohamed, Iman A; Alemrayat, Bayan; Al-Sulaiti, Fatima; Mlih, Mohamed; Mraiche, Fatima

    2015-01-01

    Studies using pharmacological and genetic approaches have shown that increased activity/expression of the Na+/H+ exchanger isoform 1 (NHE1) play a critical role in the pathogenesis of cardiac hypertrophy. Despite the importance of NHE1 in cardiac hypertrophy, severe cerebrovascular side effects were associated with the use of NHE1 inhibitors when administered to patients with myocardial infarctions. p90 ribosomal S6 Kinase (RSK), a downstream regulator of the mitogen-activated protein kinase pathway, has also been implicated in cardiac hypertrophy. We hypothesized that RSK plays a role in the NHE1 induced cardiomyocyte hypertrophic response. Infection of H9c2 cardiomyoblasts with the active form of the NHE1 adenovirus induced hypertrophy and was associated with an increase in the phosphorylation of RSK (P<0.05). Parameters of hypertrophy such as cell area, protein content and atrial natriuretic mRNA expression were significantly reduced in H9c2 cardiomyoblasts infected with active NHE1 in the presence of dominant negative RSK (DN-RSK) (P<0.05). These results confirm that NHE1 lies upstream of RSK. Increased phosphorylation and activation of GATA4 at Ser261 was correlated with increased RSK phosphorylation. This increase was reversed upon inhibition of RSK or NHE1. These findings demonstrate for the first time that the NHE1 mediated hypertrophy is accounted for by increased activation and phosphorylation of RSK, which subsequently increased the phosphorylation of GATA4; eventually activating fetal gene transcriptional machinery.

  13. UCR1C is a novel activator of phosphodiesterase 4 (PDE4) long isoforms and attenuates cardiomyocyte hypertrophy

    PubMed Central

    Wang, Li; Burmeister, Brian T.; Johnson, Keven R.; Baillie, George S.; Karginov, Andrei V.; Skidgel, Randal A.; O’Bryan, John P.; Carnegie, Graeme K.

    2015-01-01

    Hypertrophy increases the risk of heart failure and arrhythmia. Prevention or reversal of the maladaptive hypertrophic phenotype has thus been proposed to treat heart failure. Chronic β-adrenergic receptor (β-AR) stimulation induces cardiomyocyte hypertrophy by elevating 3′, 5′-cyclic adenosine monophosphate (cAMP) levels and activating downstream effectors such protein kinase A (PKA). Conversely, hydrolysis of cAMP by phosphodiesterases (PDEs) spatiotemporally restricts cAMP signaling. Here, we demonstrate that PDE4, but not PDE3, is critical in regulating cardiomyocyte hypertrophy, and may represent a potential target for preventing maladaptive hypertrophy. We identify a sequence within the upstream conserved region 1 of PDE4D, termed UCR1C, as a novel activator of PDE4 long isoforms. UCR1C activates PDE4 in complex with A-Kinase anchoring protein (AKAP)-Lbc resulting in decreased PKA signaling facilitated by AKAP-Lbc. Expression of UCR1C in cardiomyocytes inhibits hypertrophy in response to chronic β-AR stimulation. This effect is partially due to inhibition of nuclear PKA activity, which decreases phosphorylation of the transcription factor cAMP response element-binding protein (CREB). In conclusion, PDE4 activation by UCR1C attenuates cardiomyocyte hypertrophy by specifically inhibiting nuclear PKA activity. PMID:25683917

  14. ZNF307 (Zinc Finger Protein 307) Acts as a Negative Regulator of Pressure Overload-Induced Cardiac Hypertrophy.

    PubMed

    Yu, Chang-Jiang; Liang, Chen; Li, Yu-Xia; Hu, Qing-Qing; Zheng, Wei-Wan; Niu, Na; Yang, Xu; Wang, Zi-Rui; Yu, Xiao-Di; Zhang, Bao-Long; Song, Bin-Lin; Zhang, Zhi-Ren

    2017-04-01

    Pathological cardiac hypertrophy is a key risk factor for heart failure. We found that the protein expression levels of the ZNF307 (zinc finger protein 307) were significantly increased in heart samples from both human patients with dilated cardiomyopathy and mice subjected to aortic banding. Therefore, we aimed to elucidate the role of ZNF307 in the development of cardiac hypertrophy and to explore the signal transduction events that mediate the effect of ZNF307 on cardiac hypertrophy, using cardiac-specific ZNF307 transgenic (ZNF307-TG) mice and ZNF307 global knockout (ZNF307-KO) mice. The results showed that the deletion of ZNF307 potentiated aortic banding-induced pathological cardiac hypertrophy, fibrosis, and cardiac dysfunction; however, the aortic banding-induced cardiac hypertrophic phenotype was dramatically diminished by ZNF307 overexpression in mouse heart. Mechanistically, the antihypertrophic effects mediated by ZNF307 in response to pathological stimuli were associated with the direct inactivation of NF-κB (nuclear factor-κB) signaling and blockade of the nuclear translocation of NF-κB subunit p65. Furthermore, the overexpression of a degradation-resistant mutant of IκBα (IκBα(S32A/S36A)) reversed the exacerbation of cardiac hypertrophy, fibrosis, and dysfunction shown in aortic banding-treated ZNF307-KO mice. In conclusion, our findings demonstrate that ZNF307 ameliorates pressure overload-induced cardiac hypertrophy by inhibiting the activity of NF-κB-signaling pathway.

  15. Hepatocyte Death: A Clear and Present Danger

    PubMed Central

    MALHI, HARMEET; GUICCIARDI, MARIA EUGENIA; GORES, GREGORY J.

    2010-01-01

    The hepatocyte is especially vulnerable to injury due to its central role in xenobiotic metabolism including drugs and alcohol, participation in lipid and fatty acid metabolism, its unique role in the enterohepatic circulation of bile acids, the widespread prevalence of hepatotropic viruses, and its existence within a milieu of innate immune responding cells. Apoptosis and necrosis are the most widely recognized forms of hepatocyte cell death. The hepatocyte displays many unique features regarding cell death by apoptosis. It is quite susceptible to death receptor-mediated injury, and its death receptor signaling pathways involve the mitochondrial pathway for efficient cell killing. Also, death receptors can trigger lysosomal disruption in hepatocytes which further promote cell and tissue injury. Interestingly, hepatocytes are protected from cell death by only two anti-apoptotic proteins, Bcl-xL and Mcl-1, which have nonredundant functions. Endoplasmic reticulum stress or the unfolded protein response contributes to hepatocyte cell death during alterations of lipid and fatty acid metabolism. Finally, the current information implicating RIP kinases in necrosis provides an approach to more fully address this mode of cell death in hepatocyte injury. All of these processes contributing to hepatocyte injury are discussed in the context of potential therapeutic strategies. PMID:20664081

  16. Comparison between true and partial hemifacial hypertrophy.

    PubMed

    Islam, Mohammed N; Bhattacharyya, Indraneel; Ojha, Junu; Bober, Karen; Cohen, Donald M; Green, James G

    2007-10-01

    Hemifacial hypertrophy (HFH) is rare and characterized by unilateral enlargement of the head and teeth. Hemifacial hypertrophy is classified as true HFH (THFH) with unilateral enlargement of the viscerocranium, and partial HFH (PHFH) in which not all structures are enlarged. We present a case of THFH and compare and contrast it with a case of PHFH. Hemifacial hypertrophy may cover a wide spectrum of defects or may involve only muscle or bone. Myohyperplasia, reported previously as a separate syndrome, may actually represent a forme fruste of PHFH or THFH. The PHFH patient lead a healthy, normal life without significant psychosocial problems and was reluctant to accept his deformity. Contrastingly, the THFH patient had significant social stigma and compromised health together with major aesthetic morbidity. Treatment planning in THFH is arduous and involves multiple modalities. Therefore, it is imperative to differentiate THFH and PHFH for better understanding and management of the condition.

  17. Myocardial hypertrophy induces carotid body hyperplasia.

    PubMed

    Sivridis, Efthimios; Pavlidis, Pavlos; Fiska, Aliki; Pitsiava, Dimitra; Giatromanolaki, Alexandra

    2011-01-01

    The carotid bodies tend to enlarge after long-standing cardiopulmonary disease. Our objective was to investigate whether cardiac hypertrophy is associated with carotid body hyperplasia. Fifteen autopsy cases with combined left and right ventricular hypertrophy were examined and compared with two control groups (16 cases). The study involved a meticulous dissection of carotid bifurcations, thin serial sections, and morphometric analysis of carotid body volume and cell types (progenitor, dark, light, and sustentacular). There was a significant increase in sustentacular cells in all individuals with cardiac hypertrophy, which was not drug-induced, and accompanied by a similar increase in carotid body volume. Dark or light cell accumulation was detected focally and only in three instances. It appears that the generalized sustentacular cell hyperplasia is the result of long-standing hypoxia, while a superimposed focal prominence of dark or light cells may be proliferative or metaplastic in nature and attributed to short-term hypoxia.

  18. Embryonic hepatocyte transplantation for hepatic cirrhosis: Efficacy and mechanism of action

    PubMed Central

    Bin, Wen-Ting; Ma, Li-Mei; Xu, Qing; Shi, Xiao-Lin

    2012-01-01

    AIM: To investigate the efficacy and mechanism of action of allogeneic embryonic hepatocyte transplantation for the treatment of hepatic cirrhosis. METHODS: Rat embryonic hepatocytes were characterized by examining cell markers. Wistar rats with CCl4-induced cirrhosis were randomly divided into two groups: a model group receiving continuous CCl4, and a cell transplantation group receiving continuous CCl4 and transplanted with embryonic fluorescent-labeled hepatocytes. In addition, a normal control group was composed of healthy rats. All rats were sacrificed after 2 wk following the initiation of the cell transplant. Ultrasound, pathological analyses and serum biochemical tests were used to evaluate the efficacy of embryonic hepatocyte transplantation. To analyze the recovery status of cirrhotic hepatocytes and the signaling pathways influenced by embryonic hepatocyte transplantation, real-time polymerase chain reaction was performed to examine the mRNA expression of stellate activation-associated protein (STAP), c-myb, α smooth muscle actin (α-SMA) and endothelin-1 (ET-1). Western blotting and immunohistochemistry were employed to detect α-SMA and ET-1 protein expression in hepatic tissues. RESULTS: Gross morphological, ultrasound and histopathological examinations, serum biochemical tests and radioimmunoassays demonstrated that hepatic cirrhosis was successfully established in the Wistar rats. Stem cell factor receptor (c-kit), hepatocyte growth factor receptor (c-Met), Nestin, α fetal protein, albumin and cytokeratin19 markers were observed in the rat embryonic hepatocytes. Following embryonic hepatocyte transplantation, there was a significant reversal in the gross appearance, ultrasound findings, histopathological properties, and serum biochemical parameters of the rat liver. In addition, after the activation of hepatic stellate cells and STAP signaling, α-SMA, c-myb and ET-1 mRNA levels became significantly lower than in the untreated cirrhotic group (P

  19. Hepatocyte transplantation-biology and application.

    PubMed

    Gewartowska, M; Olszewski, Waldemar L

    2007-01-01

    Transplantation of liver has been remarkably effective in the treatment of liver failure and liver-based inherited metabolic diseases and has revolutionized the care of patients with end-stage liver disease. Unfortunately demand for transplantable livers is progressively outpacing the supply of donated cadaver organs, resulting in longer waiting times and increased mortality for prospective transplant recipients. Hepatocyte transplantation has been proposed as a method to support patients with liver insufficiency. The current knowledge on this method has been review in this article. Now the two-step collagenase perfusion technique is widely used for isolation of hepatocytes. Liver has been considered as an optimal site for hepatocyte transplantation, however, even in this organ the survival rate of transplanted hepatocytes in extremely low. The main obstacle for wider usage of hepatocyte transplantation is their rapid elimination by recipient macrophages. We tried in animal experiments to downregulate the innate process of recipient cellular attack on implanted hepatocytes by irradiation of recipient and elimination of NK cells. Ligation of bile duct and partial hepatectomies facilitated proliferation of accepted donor hepatocytes and formation of bile canaliculi. The described method is now adjusted to clinical conditions.

  20. Skeletal Muscle Hypertrophy after Aerobic Exercise Training

    PubMed Central

    Konopka, Adam R.; Harber, Matthew P.

    2014-01-01

    Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss. PMID:24508740

  1. Role of α1D -adrenoceptors in vascular wall hypertrophy during angiotensin II-induced hypertension.

    PubMed

    Gallardo-Ortíz, I A; Rodríguez-Hernández, S N; López-Guerrero, J J; Del Valle-Mondragón, L; López-Sánchez, P; Touyz, R M; Villalobos-Molina, R

    2015-09-01

    The in vivo effect of continuous angiotensin II (Ang II) infusion on arterial blood pressure, vascular hypertrophy and α1 -adrenoceptors (α1 -ARs) expression was explored. Alzet(®) minipumps filled with Ang II (200 ng kg(-1)  min(-1) ) were subcutaneously implanted in male Wistar rats (3 months-old). Groups of rats were also treated with losartan, an AT1 R antagonist, or with BMY 7378, a selective α1D -AR antagonist. Blood pressure was measured by tail-cuff; after 2 or 4 weeks of treatment, vessels were isolated for functional and structural analyses. Angiotensin II increased systolic blood pressure. Phenylephrine-induced contraction in aorta was greater (40% higher) in Ang II-treated rats than in the controls, and similar effect occurred with KCl 80 mm. Responses in tail arteries were not significantly different among the different groups. Angiotensin II decreased α1D -ARs without modifying the other α1 -ARs and induced an increase in media thickness (hypertrophy) in aorta, while no structural change occurred in tail artery. Losartan prevented and reversed hypertension and hypertrophy, while BMY 7378 prevented and reversed the aorta's hypertrophic response, without preventing or reversing hypertension. Findings indicate that Ang II-induced aortic hypertrophic response involves Ang II-AT1 Rs and α1D -ARs. Angiotensin II-induced α1D -AR-mediated vascular remodeling occurs independently of hypertension. Findings identify a α1D -AR-mediated process whereby Ang II influences aortic hypertrophy independently of blood pressure elevation.

  2. Hepatic stellate cell-expressed endosialin balances fibrogenesis and hepatocyte proliferation during liver damage

    PubMed Central

    Mogler, Carolin; Wieland, Matthias; König, Courtney; Hu, Junhao; Runge, Anja; Korn, Claudia; Besemfelder, Eva; Breitkopf-Heinlein, Katja; Komljenovic, Dorde; Dooley, Steven; Schirmacher, Peter; Longerich, Thomas; Augustin, Hellmut G

    2015-01-01

    Liver fibrosis is a reversible wound-healing response to injury reflecting the critical balance between liver repair and scar formation. Chronic damage leads to progressive substitution of liver parenchyma by scar tissue and ultimately results in liver cirrhosis. Stromal cells (hepatic stellate cells [HSC] and endothelial cells) have been proposed to control the balance between liver fibrosis and regeneration. Here, we show that endosialin, a C-type lectin, expressed in the liver exclusively by HSC and portal fibroblasts, is upregulated in liver fibrosis in mouse and man. Chronic chemically induced liver damage resulted in reduced fibrosis and enhanced hepatocyte proliferation in endosialin-deficient (ENKO) mice. Correspondingly, acute-liver-damage-induced hepatocyte proliferation (partial hepatectomy) was increased in ENKO mice. A candidate-based screen of known regulators of hepatocyte proliferation identified insulin-like growth factor 2 (IGF2) as selectively endosialin-dependent hepatocyte mitogen. Collectively, the study establishes a critical role of HSC in the reciprocal regulation of fibrogenesis vs. hepatocyte proliferation and identifies endosialin as a therapeutic target in non-neoplastic settings. PMID:25680861

  3. Progressive induction of hepatocyte progenitor cells in chronically injured liver

    PubMed Central

    Tanimizu, Naoki; Ichinohe, Norihisa; Yamamoto, Masahiro; Akiyama, Haruhiko; Nishikawa, Yuji; Mitaka, Toshihiro

    2017-01-01

    Differentiated epithelial cells show substantial lineage plasticity upon severe tissue injuries. In chronically injured mouse livers, part of hepatocytes become Sry-HMG box containing 9 (Sox9) (+) epithelial cell adhesion molecule (−) hepatocyte nuclear factor 4 α (+) biphenotypic hepatocytes. However, it is not clear whether all Sox9+ hepatocytes uniformly possess cellular properties as hepatocyte progenitors. Here, we examined the microarray data comparing Sox9+ hepatocytes with mature hepatocytes and identified CD24 as a novel marker for biphenotypic hepatocytes. Immunohistochemical analyses showed that part of Sox9+ hepatocytes near expanded ductular structures expressed CD24 in the liver injured by 3,5-diethoxycarbonyl-1,4-dihydro-collidine (DDC) diet and by bile duct ligation. Indeed, Sox9+ hepatocytes could be separated into CD24− and CD24+ cells by fluorescence activated cell sorting. The ratio of CD24+ cells against CD24− ones in Sox9+ hepatocytes gradually increased while DDC-injury progressed and colony-forming capability mostly attributed to CD24+ cells. Although hepatocyte markers were remarkably downregulated in of Sox9+ CD24+ hepatocytes, they re-differentiated into mature hepatocytes in vitro and in vivo. Our current results demonstrate that the emergence of biphenotypic hepatocytes is a sequential event including the transition from CD24− and CD24+ status, which may be a crucial step for hepatocytes to acquire progenitor properties. PMID:28051157

  4. Reduced expression of mature TGF beta 1 correlates with the suppression of rat hepatocyte apoptosis by the peroxisome proliferator, nafenopin.

    PubMed

    Strange, J; Roberts, R A

    1996-11-11

    Non-genotoxic carcinogens cause cancer without damaging the DNA. Peroxisome proliferators (PPs) are a class of potent rodent non-genotoxic hepatocarcinogens that may act by perturbing hepatocyte growth regulation. Previously, we have shown that although cultured rat hepatocytes degenerate rapidly in culture, their survival can be reversibly maintained by the PP nafenopin. This prolonged survival is associated with a decrease in the number of hepatocytes displaying the chromatin condensation characteristic of apoptosis. The addition of the negative growth regulator TGF beta-1 induced high levels of hepatocyte apoptosis but nafenopin was able to suppress this TGF beta-1 induced apoptosis. These data suggested that increased levels of mature TGF beta-1 may be involved in the signalling of the apoptosis seen in degenerating hepatocyte cultures. To test this hypothesis, we carried out Western blot analyses using a anti-TGF beta 1 antibody. There was an increase (p = 0.014) in expression of mature TGF beta 1 in degenerating rat hepatocyte cultures compared with hepatocyte cultures surviving in the presence of nafenopin. However, there was a concomitant decrease (p = 0.024) in TGF beta 1-latency activated protein (TGF beta 1-LAP), the precursor of the active, mature form. Immunocytochemistry confirmed that TGF beta 1/TGF beta 1-LAP expression was predominantly in the hepatocytes displaying apoptotic morphology although expression was detected also in non-parenchymal liver cells. The immunocytochemistry data indicate that TGF beta 1 is involved during the onset of hepatocyte apoptosis and that the PP nafenopin can impinge on this cell death pathway. TGF beta 1-LAP, probably produced mainly by the non-parenchymal liver cells, may be processed less efficiently to the mature, active form in the presence of nafenopin, although more data are required to confirm this hypothesis.

  5. Compensatory renal hypertrophy following uninephrectomy is calcineurin-independent.

    PubMed

    Williams, Clintoria R; Wynne, Brandi M; Walker, Makeeva; Hoover, Robert S; Gooch, Jennifer L

    2014-12-01

    Calcineurin is a calcium-dependent phosphatase that is involved in many cellular processes including hypertrophy. Inhibition or genetic loss of calcineurin blocks pathological cardiac hypertrophy and diabetic renal hypertrophy. However, calcineurin does not appear to be involved in physiological cardiac hypertrophy induced by exercise. The role of calcineurin in a compensatory, non-pathological model of renal hypertrophy has not been tested. Therefore, in this study, we examined activation of calcineurin and the effect of calcineurin inhibition or knockout on compensatory hypertrophy following uninephrectomy (UNX). UNX induces ~15% increase in the size of the remaining kidney; the data show no change in the generation of reactive oxygen species (ROS), Nox4 or transforming growth factor-β expression confirming the model as one of compensatory hypertrophy. Next, analyses of the remaining kidney reveal that total calcineurin activity is increased, and, to a lesser extent, transcriptional activity of the calcineurin substrate nuclear factor of activated T cell is up-regulated following UNX. However, inhibition of calcineurin with cyclosporine failed to prevent compensatory renal hypertrophy. Likewise, hypertrophy was comparable to WT in mice lacking either isoform of the catalytic subunit of calcineurin (CnAα-/- or CnAβ-/-). In conclusion, similar to its role in the heart, calcineurin is required for pathological but not compensatory renal hypertrophy. This separation of signalling pathways could therefore help further define key factors necessary for pathological hypertrophy including diabetic nephropathy.

  6. Hepatocyte β-Klotho regulates lipid homeostasis but not body weight in mice.

    PubMed

    Kobayashi, Kanako; Tanaka, Tomohiro; Okada, Sadanori; Morimoto, Yuki; Matsumura, Shigenobu; Manio, Mark Christian C; Inoue, Kazuo; Kimura, Kumi; Yagi, Takashi; Saito, Yoshihiko; Fushiki, Tohru; Inoue, Hiroshi; Matsumoto, Michihiro; Nabeshima, Yo-Ichi

    2016-02-01

    β-Klotho (β-Kl), a transmembrane protein expressed in the liver, pancreas, adipose tissues, and brain, is essential for feedback suppression of hepatic bile acid synthesis. Because bile acid is a key regulator of lipid and energy metabolism, we hypothesized potential and tissue-specific roles of β-Kl in regulating plasma lipid levels and body weight. By crossing β-kl(-/-) mice with newly developed hepatocyte-specific β-kl transgenic (Tg) mice, we generated mice expressing β-kl solely in hepatocytes (β-kl(-/-)/Tg). Gene expression, metabolomic, and in vivo flux analyses consistently revealed that plasma level of cholesterol, which is over-excreted into feces as bile acids in β-kl(-/-), is maintained in β-kl(-/-) mice by enhanced de novo cholesterogenesis. No compensatory increase in lipogenesis was observed, despite markedly decreased plasma triglyceride. Along with enhanced bile acid synthesis, these lipid dysregulations in β-kl(-/-) were completely reversed in β-kl(-/-)/Tg mice. In contrast, reduced body weight and resistance to diet-induced obesity in β-kl(-/-) mice were not reversed by hepatocyte-specific restoration of β-Kl expression. We conclude that β-Kl in hepatocytes is necessary and sufficient for lipid homeostasis, whereas nonhepatic β-Kl regulates energy metabolism. We further demonstrate that in a condition with excessive cholesterol disposal, a robust compensatory mechanism maintains cholesterol levels but not triglyceride levels in mice.

  7. In utero Transplanted Human Hepatocytes Allows for Postnatal Engraftment of Human Hepatocytes in Pigs

    PubMed Central

    Fisher, James E; Lillegard, Joseph B; Mckenzie, Travis J; Rodysill, Brian R; Wettstein, Peter J; Nyberg, Scott L

    2012-01-01

    In utero cell transplantation (IUCT) can lead to postnatal engraftment of human cells in the xenogeneic recipient. Most reports of IUCTs have involved hematopoietic stem cells. It is unknown if human hepatocytes used for IUCT in fetal pigs will lead to engraftment of these same cells in the postnatal environment. In this study, fetal pigs received direct liver injections of 1×107 human hepatocytes in utero and were delivered by cesarean-section at term. Piglets received a second direct liver injection of 5×107 human hepatocytes 1 week postnatally. Serum was analyzed for human albumin at 2, 4, and 6 weeks post-engraftment. Piglet livers were harvested 6 weeks after transplantation and examined by immunohistochemistry, PCR and fluorescence in situ hybridization for human specific sequences. Piglets receiving IUCT with human hepatocytes that were postnatally engrafted with human hepatocytes showed significant levels of human albumin production in their serum at all post-engraftment time points. Human albumin gene expression, the presence of human hepatocytes and the presence of human beta-2 microglobulin were all confirmed 6 weeks post-engraftment. IUCT in fetal pigs using human hepatocytes early in gestation allowed for engraftment of human hepatocytes, which remained viable and functional for weeks after transplantation. IUCT followed by postnatal engraftment may provide a future means for large scale expansion of human hepatocytes in genetically-engineered pigs. PMID:23280879

  8. Tanshinone IIA Prevents Leu27IGF-II-Induced Cardiomyocyte Hypertrophy Mediated by Estrogen Receptor and Subsequent Akt Activation.

    PubMed

    Weng, Yueh-Shan; Wang, Hsueh-Fang; Pai, Pei-Ying; Jong, Gwo-Ping; Lai, Chao-Hung; Chung, Li-Chin; Hsieh, Dennis Jine-Yuan; HsuanDay, Cecilia; Kuo, Wei-Wen; Huang, Chih-Yang

    2015-01-01

    IGF-IIR plays important roles as a key regulator in myocardial pathological hypertrophy and apoptosis, which subsequently lead to heart failure. Salvia miltiorrhiza Bunge (Danshen) is a traditional Chinese medicinal herb used to treat cardiovascular diseases. Tanshinone IIA is an active compound in Danshen and is structurally similar to 17[Formula: see text]-estradiol (E[Formula: see text]. However, whether tanshinone IIA improves cardiomyocyte survival in pathological hypertrophy through estrogen receptor (ER) regulation remains unclear. This study investigates the role of ER signaling in mediating the protective effects of tanshinone IIA on IGF-IIR-induced myocardial hypertrophy. Leu27IGF-II (IGF-II analog) was shown in this study to specifically activate IGF-IIR expression and ICI 182,780 (ICI), an ER antagonist used to investigate tanshinone IIA estrogenic activity. We demonstrated that tanshinone IIA significantly enhanced Akt phosphorylation through ER activation to inhibit Leu27IGF-II-induced calcineurin expression and subsequent NFATc3 nuclear translocation to suppress myocardial hypertrophy. Tanshinone IIA reduced the cell size and suppressed ANP and BNP, inhibiting antihypertrophic effects induced by Leu27IGF-II. The cardioprotective properties of tanshinone IIA that inhibit Leu27IGF-II-induced cell hypertrophy and promote cell survival were reversed by ICI. Furthermore, ICI significantly reduced phospho-Akt, Ly294002 (PI3K inhibitor), and PI3K siRNA significantly reduced the tanshinone IIA-induced protective effect. The above results suggest that tanshinone IIA inhibited cardiomyocyte hypertrophy, which was mediated through ER, by activating the PI3K/Akt pathway and inhibiting Leu27IGF-II-induced calcineurin and NFATC3. Tanshinone IIA exerted strong estrogenic activity and therefore represented a novel selective ER modulator that inhibits IGF-IIR signaling to block cardiac hypertrophy.

  9. Urotensin II induction of neonatal cardiomyocyte hypertrophy involves the CaMKII/PLN/SERCA 2a signaling pathway.

    PubMed

    Shi, Hongtao; Han, Qinghua; Xu, Jianrong; Liu, Wenyuan; Chu, Tingting; Zhao, Li

    2016-05-25

    Although studies have shown that Urotensin II (UII) can induce cardiomyocyte hypertrophy and UII-induced cardiomyocyte hypertrophy model has been widely used for hypertrophy research, but its precise mechanism remains unknown. Recent researches have demonstrated that UII-induced cardiomyocyte hypertrophy has a relationship with the changes of intracellular Ca(2+) concentration. Therefore, the aim of this study was to investigate the mechanisms of cardiomyocyte hypertrophy induced by UII and to explore whether the calcium/calmodulin-dependent protein kinase II (CaMKII)-mediated up-regulating of phospholamban (PLN) Thr17-phosphorylation signaling pathway contributed to UII-induced cardiomyocyte hypertrophy. Primary cultures of neonatal rat cardiomyocytes were stimulated for 48h with UII. Cell size, protein/DNA contents and intracellular Ca(2+) were determined. Phosphorylated and total forms of CaMKII, PLN and the total amount of serco/endo-plasmic reticulum ATPases (SERCA 2a) were quantified by western blot. The responses of cardiomyocytes to UII were also evaluated after pretreatment with the CaMKII inhibitor, KN-93. These results showed that UII increased cell size, protein/DNA ratio and intracellular Ca(2+), consistent with a hypertrophic response. Furthermore, the phosphorylation of CaMKII and its downstream target PLN (Thr17), SERCA 2a levels were up-regulated by UII treatment. Conversely, treatment with KN-93 reversed all those effects of UII. Taken together, the results suggest that UII can induce cardiomyocyte hypertrophy through CaMKII-mediated up-regulating of PLN Thr17-phosphorylation signaling pathway.

  10. MiRNAs with apoptosis regulating potential are differentially expressed in chronic exercise-induced physiologically hypertrophied hearts.

    PubMed

    Ramasamy, Subbiah; Velmurugan, Ganesan; Shanmugha Rajan, K; Ramprasath, Tharmarajan; Kalpana, Krishnan

    2015-01-01

    Physiological cardiac hypertrophy is an adaptive mechanism, induced during chronic exercise. As it is reversible and not associated with cardiomyocyte death, it is considered as a natural tactic to prevent cardiac dysfunction and failure. Though, different studies revealed the importance of microRNAs (miRNAs) in pathological hypertrophy, their role during physiological hypertrophy is largely unexplored. Hence, this study is aimed at revealing the global expression profile of miRNAs during physiological cardiac hypertrophy. Chronic swimming protocol continuously for eight weeks resulted in induction of physiological hypertrophy in rats and histopathology revealed the absence of tissue damage, apoptosis or fibrosis. Subsequently, the total RNA was isolated and small RNA sequencing was executed. Analysis of small RNA reads revealed the differential expression of a large set of miRNAs during physiological hypertrophy. The expression profile of the significantly differentially expressed miRNAs was validated by qPCR. In silico prediction of target genes by miRanda, miRdB and TargetScan and subsequent qPCR analysis unraveled that miRNAs including miR-99b, miR-100, miR-19b, miR-10, miR-208a, miR-133, miR-191a, miR-22, miR-30e and miR-181a are targeting the genes that primarily regulate cell proliferation and cell death. Gene ontology and pathway mapping showed that the differentially expressed miRNAs and their target genes were mapped to apoptosis and cell death pathways principally via PI3K/Akt/mTOR and MAPK signaling. In summary, our data indicates that regulation of these miRNAs with apoptosis regulating potential can be one of the major key factors in determining pathological or physiological hypertrophy by controlling fibrosis, apoptosis and cell death mechanisms.

  11. Activation of factor X by rat hepatocytes

    SciTech Connect

    Willingham, A.K.; Matschiner, J.T.

    1986-05-01

    Synthesis and secretion of blood coagulation factor X was studied in hepatocytes prepared by perfusion of rat livers with collagenase. Hepatocytes were incubated in the presence of vitamin K and /sup 3/H-leucine for up to 4h at 37/sup 0/C. Factor X was isolated from the incubation medium by immunochemical techniques and analyzed by SDS-PAGE. The recovered /sup 3/H-labeled proteins migrated, after reduction of disulfides, as two polypeptide chains with apparent molecular weights (M/sub r/) of approximately 42,000 and 22,000 representing the heavy and light chains of factor X respectively. The apparent M/sub r/ of the heavy chain was about 10,000 daltons lighter than seen with the heavy chain of factor X isolated from rat plasma and was more characteristic of the heavy chain of factor Xa. When the levels of factor X secreted by hepatocytes were determined by clotting assays, activity was present as factor Xa. Also, when purified plasma factor X was added to incubations of hepatocytes (>95% parenchymal cells) the added factor X was rapidly converted to factor Xa. Plasma membranes prepared from isolated hepatocytes or from liver homogenates contained an enzyme that converted factor X to factor Xa in a calcium dependent reaction. The physiological significance of a factor X activating enzyme on hepatocyte plasma membranes is not clear.

  12. Selective insulin resistance in hepatocyte senescence

    SciTech Connect

    Aravinthan, Aloysious; Challis, Benjamin; Shannon, Nicholas; Hoare, Matthew; Heaney, Judith; Alexander, Graeme J.M.

    2015-02-01

    Insulin resistance has been described in association with chronic liver disease for decades. Hepatocyte senescence has been demonstrated in chronic liver disease and as many as 80% of hepatocytes show a senescent phenotype in advanced liver disease. The aim of this study was to understand the role of hepatocyte senescence in the development of insulin resistance. Senescence was induced in HepG2 cells via oxidative stress. The insulin metabolic pathway was studied in control and senescent cells following insulin stimulation. GLUT2 and GLUT4 expressions were studied in HepG2 cells and human liver tissue. Further, GLUT2 and GLUT4 expressions were studied in three independent chronic liver disease cohorts. Signalling impairment distal to Akt in phosphorylation of AS160 and FoxO1 was evident in senescent HepG2 cells. Persistent nuclear localisation of FoxO1 was demonstrated in senescent cells despite insulin stimulation. Increased GLUT4 and decreased GLUT2 expressions were evident in senescent cells, human cirrhotic liver tissue and publically available liver disease datasets. Changes in GLUT expressions were associated with a poor clinical prognosis. In conclusion, selective insulin resistance is evident in senescent HepG2 cells and changes in GLUT expressions can be used as surrogate markers of hepatocyte senescence. - Highlights: • Senescent hepatocytes demonstrate selective insulin resistance. • GLUT changes act as markers of hepatocyte senescence and have prognostic value. • Study offers insight into long noticed intimacy of cirrhosis and insulin resistance.

  13. Proliferation of rat small hepatocytes requires follistatin expression.

    PubMed

    Ooe, Hidekazu; Chen, Qijie; Kon, Junko; Sasaki, Kazunori; Miyoshi, Hiroyuki; Ichinohe, Norihisa; Tanimizu, Naoki; Mitaka, Toshihiro

    2012-06-01

    Small hepatocytes (SHs) are a subpopulation of hepatocytes that have high growth potential in culture and can differentiate into mature hepatocytes (MHs). The activin (Act)/follistatin (Fst) system critically contributes to homeostasis of cell growth in the normal liver. ActA and ActB consist of two disulfide-linked Inhibin (Inh)β subunits, InhβA and InhβB, respectively. Fst binds to Act and blocks its bioactivity. In the present study we carried out the experiments to clarify how Fst regulates the proliferation of SHs. The gene expression was analyzed using DNA microarray analysis, reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR, and protein expression was examined by western blots, immunocytochemistry, and enzyme-linked immunosorbent assay. RT-PCR showed that Fst expression was high in SHs and low in MHs. Although the ActA expression was opposite to that of Fst, ActB expression was high in SHs and low in MHs and increased with time in culture. Fst protein was detected in the cytoplasm of SHs and secreted into the culture medium. ActB protein was also secreted into the medium. Although the exogenous administration of ActA and ActB apparently suppressed the proliferation of SHs, apoptosis of SHs was not induced by treatment with ActA or ActB. On the other hand, Fst treatment did not affect the colony formation of SHs but prevented the inhibitory effect of ActA. Neutralization by the anti-Fst antibody resulted in the suppression of DNA synthesis in SHs, and small hairpin RNA against Fst suppressed the expansion of SH colonies. In conclusion, Fst expression is necessary for the proliferation of SHs.

  14. Involvement of matrix metalloproteinase-2 in medial hypertrophy of pulmonary arterioles in broiler chickens with pulmonary arterial hypertension.

    PubMed

    Tan, Xun; Chai, Juan; Bi, Shi-Cheng; Li, Jun-Jun; Li, Wen-Wen; Zhou, Ji-Yong

    2012-08-01

    Medial hypertrophy of pulmonary arterioles during pulmonary arterial hypertension (PAH) in humans is associated with enhanced proliferation of smooth muscle cells (SMCs). Elevated matrix metalloproteinase (MMP)-2 has been found in pulmonary artery SMCs (PA-SMCs) in humans with idiopathic PAH, leading to the hypothesis that MMP-2 contributes to the proliferation and migration of vascular SMCs in the pathogenesis of PAH. Rapidly growing meat-type (broiler) chickens provide a model of spontaneous PAH. The present study was conducted to determine whether MMP-2 is involved in the medial hypertrophy of pulmonary arterioles in this model. Cultured PA-SMCs from normal birds were used to evaluate the effect of MMPs on cell proliferation. Gelatin zymography showed that endothelin (ET)-1-induced proliferation of PA-SMCs was concomitant with increased pro- and active MMP-2 production. Reverse transcription PCR demonstrated upregulation of MMP-2 mRNA. However, PA-SMC proliferation was inhibited by the MMP inhibitors doxycycline and cis-9-octadecenoyl-N-hydroxylamide. In vivo experiments revealed a significant increase of MMP-2 expression in hypertrophied pulmonary arterioles of PAH broiler chickens, which was positively correlated with wall thickness and medial hypertrophy. MMP-2 may contribute to medial hypertrophy in pulmonary arterioles during PAH in broiler chickens by enhancing the proliferation of vascular SMCs.

  15. Gingival hypertrophy: a solitary manifestation of scurvy.

    PubMed

    Li, Ryan; Byers, Karin; Walvekar, Rohan R

    2008-01-01

    A 48-year-old woman presented with rapid onset hypertrophy of both the upper and lower gingiva. A detailed history and a diet nearly void of fruits and vegetables raised the suspicion of a possible deficiency of vitamin C. An estimation of the serum ascorbic acid level confirmed our suspicions (<0.12 mg/dL; normal range, 0.4-1.0 mg/dL) and a diagnosis of scurvy was confirmed. A course of 1000 mg/d of ascorbic acid was initiated that caused a dramatic resolution of the gingival lesions. Gingival hypertrophy has a large differential diagnosis; however, it is also known to be an extremely rare manifestation of scurvy. A high index of suspicion for scurvy is relevant given its low prevalence in developed nations and how easily remediable the disease can be, even when it presents in a severe form.

  16. Organic anion uptake by hepatocytes.

    PubMed

    Wolkoff, Allan W

    2014-10-01

    Many of the compounds taken up by the liver are organic anions that circulate tightly bound to protein carriers such as albumin. The fenestrated sinusoidal endothelium of the liver permits these compounds to have access to hepatocytes. Studies to characterize hepatic uptake of organic anions through kinetic analyses, suggested that it was carrier-mediated. Attempts to identify specific transporters by biochemical approaches were largely unsuccessful and were replaced by studies that utilized expression cloning. These studies led to identification of the organic anion transport proteins (oatps), a family of 12 transmembrane domain glycoproteins that have broad and often overlapping substrate specificities. The oatps mediate Na(+)-independent organic anion uptake. Other studies identified a seven transmembrane domain glycoprotein, Na(+)/taurocholate transporting protein (ntcp) as mediating Na(+)-dependent uptake of bile acids as well as other organic anions. Although mutations or deficiencies of specific members of the oatp family have been associated with transport abnormalities, there have been no such reports for ntcp, and its physiologic role remains to be determined, although expression of ntcp in vitro recapitulates the characteristics of Na(+)-dependent bile acid transport that is seen in vivo. Both ntcp and oatps traffic between the cell surface and intracellular vesicular pools. These vesicles move through the cell on microtubules, using the microtubule based motors dynein and kinesins. Factors that regulate this motility are under study and may provide a unique mechanism that can alter the plasma membrane content of these transporters and consequently their accessibility to circulating ligands.

  17. Apelin/APJ system: A bifunctional target for cardiac hypertrophy.

    PubMed

    Lu, Liqun; Wu, Di; Li, Lanfang; Chen, Linxi

    2017-03-01

    Apelin acts as the endogenous ligand of G protein coupled receptors APJ. The apelin/APJ system is responsible for the occurrence and development of cardiovascular diseases. In recent years, apelin/APJ has been considered to play an important role in cardiac hypertrophy, but whether that role is beneficial or aggravating remains controversial. Apelin/APJ alleviates cardiac hypertrophy which is triggered by angiotensin II, oxidative stress and exercise. However, central administration of apelin induces cardiac hypertrophy. Peripheral administration of apelin also promotes the development of cardiac hypertrophy under non-pathological conditions. Furthermore, our laboratory discovers that apelin/APJ is able to induce hypertrophy of cardiomyocytes in vitro. The exact mechanism of apelin/APJ's dual effects in cardiac hypertrophy requires further study. In this paper, we review the controversies associated with apelin/APJ in cardiac hypertrophy and we elaborate the role of apelin/APJ in cardiac hypertrophy related-diseases including obesity, diabetes, hypertension, myocarditis and myocardial infarction. We conclude that further studies should emphasize more about the relationship between apelin/APJ and pathological hypertrophy especially in clinical patients. Moreover, apelin/APJ can be a promising therapeutic target for cardiac hypertrophy.

  18. Feasibility of direct oxygenation of primary-cultured rat hepatocytes using polyethylene glycol-decorated liposome-encapsulated hemoglobin (LEH).

    PubMed

    Naruto, Hirosuke; Huang, Hongyun; Nishikawa, Masaki; Kojima, Nobuhiko; Mizuno, Atsushi; Ohta, Katsuji; Sakai, Yasuyuki

    2007-10-01

    We tested the short-term efficacy of liposome-encapsulated hemoglobin (LEH) in cultured rat hepatocytes. Supplementation with LEH (20% of the hemoglobin concentration of blood) did not lower albumin production in static culture, and completely reversed the cell death and deterioration in albumin production caused by an oxygen shortage in 2D flat-plate perfusion bioreactors.

  19. Induced pluripotent stem cell–derived hepatocytes have the functional and proliferative capabilities needed for liver regeneration in mice

    PubMed Central

    Espejel, Silvia; Roll, Garrett R.; McLaughlin, K. John; Lee, Andrew Y.; Zhang, Jenny Y.; Laird, Diana J.; Okita, Keisuke; Yamanaka, Shinya; Willenbring, Holger

    2010-01-01

    The ability to generate induced pluripotent stem (iPS) cells from a patient’s somatic cells has provided a foundation for organ regeneration without the need for immune suppression. However, it has not been established that the differentiated progeny of iPS cells can effectively reverse failure of a vital organ. Here, we examined whether iPS cell–derived hepatocytes have both the functional and proliferative capabilities needed for liver regeneration in mice with fumarylacetoacetate hydrolase deficiency. To avoid biases resulting from random genomic integration, we used iPS cells generated without viruses. To exclude compensation by hepatocytes not derived from iPS cells, we generated chimeric mice in which all hepatocytes were iPS cell derived. In vivo analyses showed that iPS cells were intrinsically able to differentiate into fully mature hepatocytes that provided full liver function. The iPS cell–derived hepatocytes also replicated the unique proliferative capabilities of normal hepatocytes and were able to regenerate the liver after transplantation and two-thirds partial hepatectomy. Thus, our results establish the feasibility of using iPS cells generated in a clinically acceptable fashion for rapid and stable liver regeneration. PMID:20739754

  20. Fetal liver-derived mesenchymal stromal cells augment engraftment of transplanted hepatocytes

    PubMed Central

    Joshi, Meghnad; Patil, Pradeep B.; He, Zhong; Holgersson, Jan; Olausson, Michael; Sumitran-Holgersson, Suchitra

    2012-01-01

    Background aims One important problem commonly encountered after hepatocyte transplantation is the low numbers of transplanted cells found in the graft. If hepatocyte transplantation is to be a viable therapeutic approach, significant liver parenchyma repopulation is required. Mesenchymal stromal cells (MSC) produce high levels of various growth factors, cytokines and metalloproteinases, and have immunomodulatory effects. We therefore hypothesized that co-transplantation of MSC with human fetal hepatocytes (hFH) could augment in vivo expansion after transplantation. We investigated the ability of human fetal liver MSC (hFLMSC) to augment expansion of phenotypically and functionally well-characterized hFH. Methods Two million hFH (passage 6) were either transplanted alone or together (1:1 ratio) with green fluorescence protein-expressing hFLMSC into the spleen of C57BL/6 nude mice with retrorsine-induced liver injury. Results After 4 weeks, engraftment of cells was detected by fluorescence in situ hybridization using a human-specific DNA probe. Significantly higher numbers of cells expressing human cytokeratin (CK)8, CK18, CK19, Cysteine-rich MNNG HOS Transforming gene (c-Met), alpha-fetoprotein (AFP), human nuclear antigen, mitochondrial antigen, hepatocyte-specific antigen and albumin (ALB) were present in the livers of recipient animals co-transplanted with hFLMSC compared with those without. Furthermore, expression of human hepatocyte nuclear factor (HNF)-4α and HNF-1β, and cytochrome P450 (CYP) 3A7 mRNA was demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) in these animals. In addition, significantly increased amounts of human ALB were detected. Importantly, hFLMSC did not transdifferentiate into hepatocytes. Conclusions Our study reports the use of a novel strategy for enhanced liver repopulation and thereby advances this experimental procedure closer to clinical liver cell therapy. PMID:22424216

  1. Differentiation-Promoting Medium Additives for Hepatocyte Cultivation and Cryopreservation.

    PubMed

    Gouliarmou, Varvara; Pelkonen, Olavi; Coecke, Sandra

    2015-01-01

    Isolated primary hepatocytes are considered as the reference system for in vitro hepatic methods. Following the isolation of primary hepatocytes from liver tissue, an unfavorable process named dedifferentiation is initiated leading to the attenuation of the hepatocellular phenotype both at the morphological and functional level. Freshly isolated hepatocytes can be used immediately or can be cryopreserved for future purposes. Currently, a number of antidedifferentiation strategies exist to extend the life span of isolated hepatocytes. The addition of differentiation-promoting compounds to the hepatocyte culture medium is the oldest and simplest antidedifferentiation approach applied. In the present chapter, the most commonly used medium additives for cultivation and cryopreservation of primary hepatocytes are reviewed.

  2. Chondrocyte hypertrophy in skeletal development, growth, and disease.

    PubMed

    Sun, Margaret Man-Ger; Beier, Frank

    2014-03-01

    Most of our bones form through the process of endochondral ossification, which is tightly regulated by the activity of the cartilage growth plate. Chondrocyte maturation through the various stages of growth plate physiology ultimately results in hypertrophy. Chondrocyte hypertrophy is an essential contributor to longitudinal bone growth, but recent data suggest that these cells also play fundamental roles in signaling to other skeletal cells, thus coordinating endochondral ossification. On the other hand, ectopic hypertrophy of articular chondrocytes has been implicated in the pathogenesis of osteoarthritis. Thus, a better understanding of the processes that control chondrocyte hypertrophy in the growth plate as well as in articular cartilage is required for improved management of both skeletal growth disorders and osteoarthritis. This review summarizes recent findings on the regulation of hypertrophic chondrocyte differentiation, the cellular mechanisms involved in hypertrophy, and the role of chondrocyte hypertrophy in skeletal physiology and pathophysiology.

  3. Strategies for Optimizing Strength, Power, and Muscle Hypertrophy in Women.

    DTIC Science & Technology

    1997-09-01

    accretion and turnover that is needed for muscle hypertrophy and involves "cleaning up" the cell from the exercise -induced damage associated with...AD CONTRACT NUMBER DAMD17-95-C-5069 TITLE: Strategies for Optimizing Strength, Power, and Muscle Hypertrophy in Women PRINCIPAL INVESTIGATOR...DATES COVERED Annual (21 Aug 96 - 20 Aug 97) 4. TITLE AND SUBTITLE Strategies for Optimizing Strength, Power, and Muscle Hypertrophy in Women 6

  4. [Association of post-radiation focal muscular atrophy and hypertrophy].

    PubMed

    Serratrice, G; Sangla, I; Pouget, J; Azulay, J P

    1993-01-01

    We report a 48 year old woman who had radiotherapy for uterine carcinoma and who developed amyotrophy and muscle hypertrophy in one lower limb. Very few cases of post-radiation monomelic amyotrophy have been reported. On the other hand denervation hypertrophy was presumed to be well known. The seat of the lesions was presumed to be radicular and spinal. The mechanism of atrophy and hypertrophy is discussed.

  5. [Viscoelastic properties of relaxed papillary muscle at physiological hypertrophy].

    PubMed

    Smoliuk, L T; Lisin, R V; Kuznetsov, D A; Protsenko, Iu L

    2012-01-01

    Viscoelastic properties of relaxed rat papillary muscles at physiological hypertrophy (intensive swimming for 5 weeks) have been obtained. It has been ascertained that viscoelastic properties of hypertrophied muscles are not significantly distinguished from those of control papillary muscles. A three-dimensional model of myocardial fascicle has been verified in compliance with experimental data of biomechanical tests of hypertrophied muscles. Elastic and viscous parameters of structural elements of the model negligibly differ from the parameters of the model of a control muscle. It is shown that physiological hypertrophy has a slight influence on viscoelastic properties of papillary muscles.

  6. Sestrin 1 ameliorates cardiac hypertrophy via autophagy activation.

    PubMed

    Xue, Ruicong; Zeng, Junyi; Chen, Yili; Chen, Cong; Tan, Weiping; Zhao, Jingjing; Dong, Bin; Sun, Yu; Dong, Yugang; Liu, Chen

    2017-02-09

    Cardiac hypertrophy is one of the major risk factors of cardiovascular morbidity and mortality. Autophagy is acknowledged to be an important mechanism regulating cardiac hypertrophy. Sestrin 1, a downstream target gene of p53, has been proven to regulate autophagy. However, the role of Sestrin 1 in cardiac hypertrophy remains unknown. Our study showed that Sestrin 1 mRNA and protein expression declined in pressure overload cardiac hypertrophy and phenylephrine (PE)-induced cardiac hypertrophy. Knockdown of Sestrin 1 by RNAi deteriorated PE-induced cardiac hypertrophy, whereas the overexpression of Sestrin 1 by adenovirus transfection blunted hypertrophy. We discovered that knockdown of Sestrin 1 resulted in impaired autophagy while overexpression of Sestrin 1 resulted in increased autophagy without affecting lysosomal function. In addition, the antihypertrophic effect of Sestrin 1 overexpression was eliminated by autophagy blockade. Importantly, Sestrin 1 targets at the AMPK/mTORC1/autophagy pathway to inhibit cardiac hypertrophy by interaction with AMPK which is responsible for autophagy regulation. Taken together, our data indicate that Sestrin 1 regulates AMPK/mTORC1/autophagy axis to attenuate cardiac hypertrophy.

  7. Effects of phenobarbital on metabolism and toxicity of diclofenac sodium in rat hepatocytes in vitro.

    PubMed

    Wang, A G; Xia, T; Yuan, J; Yu, R A; Yang, K D; Chen, X M; Qu, W; Waalkes, M P

    2004-10-01

    Diclofenac sodium (DF-Na) was a nonsteroidal anti-inflammatory drug used in various aspects of inflammatory disease. The purpose of this study was to examine the effects of phenobarbital (PB) on metabolism and toxicity of DF-Na in vitro and explore the potential mechanism of DF-Na induced hepatotoxicity. Rat hepatocytes were isolated by a modification of the two-step in situ collagenase perfusion technique and the harvested rat hepatocytes were cultured with sandwich method. Control or PB (2 mM) pre-treated hepatocytes were incubated with DF-Na (0.1, 0.05 or 0.01 mM) in vitro and cytosolic enzyme leakage levels, cytochrome P450 (CYP) 3A activity, and metabolite content of DF-Na in cell culture medium were measured. The results showed that without any treatment hepatocyte CYP 3A activity gradually decreased with culture time. On day four, CYP 3A activity was 53% of the initial value. The decline of CYP 3A was partially reversed by CYP inducer PB, and the maximum induction of CYP 3A was 2.2-fold over control after continuous exposure of hepatocytes to 2 mM PB for 48 h. Lactic dehydrogenase (LDH), aspartate transaminase (AST), and alanine transamine (ALT) activity and the contents of the DF-Na metabolites 4'-hydroxydiclofenac (4'-OH-DF) and 5-hydroxydiclofenac (5-OH-DF) in media appeared to increase with increasing DF-Na concentrations, though there were no significant differences between DF-Na exposed and control hepatocytes. However, if the hepatocytes first were pre-treated with 2 mM PB for 2 days and then exposed to DF-Na, the concentrations of DF-Na metabolites and the activity of LDH in the media were significantly higher than that of control group. These findings suggest that the hepatotoxicity and metabolism of DF-Na in rat hepatocytes are increased when hepatic CYP 3A activity is increased.

  8. Cholangiocarcinomas can originate from hepatocytes in mice

    PubMed Central

    Fan, Biao; Malato, Yann; Calvisi, Diego F.; Naqvi, Syed; Razumilava, Nataliya; Ribback, Silvia; Gores, Gregory J.; Dombrowski, Frank; Evert, Matthias; Chen, Xin; Willenbring, Holger

    2012-01-01

    Intrahepatic cholangiocarcinomas (ICCs) are primary liver tumors with a poor prognosis. The development of effective therapies has been hampered by a limited understanding of the biology of ICCs. Although ICCs exhibit heterogeneity in location, histology, and marker expression, they are currently thought to derive invariably from the cells lining the bile ducts, biliary epithelial cells (BECs), or liver progenitor cells (LPCs). Despite lack of experimental evidence establishing BECs or LPCs as the origin of ICCs, other liver cell types have not been considered. Here we show that ICCs can originate from fully differentiated hepatocytes. Using a mouse model of hepatocyte fate tracing, we found that activated NOTCH and AKT signaling cooperate to convert normal hepatocytes into biliary cells that act as precursors of rapidly progressing, lethal ICCs. Our findings suggest a previously overlooked mechanism of human ICC formation that may be targetable for anti-ICC therapy. PMID:22797301

  9. Hyperinsulinemia is Associated with Increased Soluble Insulin Receptors Release from Hepatocytes

    PubMed Central

    Hiriart, Marcia; Sanchez-Soto, Carmen; Diaz-Garcia, Carlos Manlio; Castanares, Diana T.; Avitia, Morena; Velasco, Myrian; Mas-Oliva, Jaime; Macias-Silva, Marina; González-Villalpando, Clicerio; Delgado-Coello, Blanca; Sosa-Garrocho, Marcela; Vidaltamayo, Román; Fuentes-Silva, Deyanira

    2014-01-01

    It has been generally assumed that insulin circulates freely in blood. However it can also interact with plasma proteins. Insulin receptors are located in the membrane of target cells and consist of an alpha and beta subunits with a tyrosine kinase cytoplasmic domain. The ectodomain, called soluble insulin receptor (SIR) has been found elevated in patients with diabetes mellitus. We explored if insulin binds to SIRs in circulation under physiological conditions and hypothesize that this SIR may be released by hepatocytes in response to high insulin concentrations. The presence of SIR in rat and human plasmas and the culture medium of hepatocytes was explored using Western blot analysis. A purification protocol was performed to isolated SIR using affinity, gel filtration, and ion exchange chromatographies. A modified reverse hemolytic plaque assay was used to measure SIR release from cultured hepatocytes. Incubation with 1 nmol l−1 insulin induces the release of the insulin receptor ectodomains from normal rat hepatocytes. This effect can be partially prevented by blocking protease activity. Furthermore, plasma levels of SIR were higher in a model of metabolic syndrome, where rats are hyperinsulinemic. We also found increased SIR levels in hyperinsulinemic humans. SIR may be an important regulator of the amount of free insulin in circulation. In hyperinsulinemia, the amount of this soluble receptor increases and this could lead to higher amounts of insulin bound to this receptor, rather than free insulin, which is the biologically active form of the hormone. This observation could enlighten the mechanisms of insulin resistance. PMID:24995000

  10. Ammonia-induced energy disorders interfere with bilirubin metabolism in hepatocytes.

    PubMed

    Wang, Qiongye; Wang, Yanfang; Yu, Zujiang; Li, Duolu; Jia, Bin; Li, Jingjing; Guan, Kelei; Zhou, Yubing; Chen, Yanling; Kan, Quancheng

    2014-08-01

    Hyperammonemia and jaundice are the most common clinical symptoms of hepatic failure. Decreasing the level of ammonia in the blood is often accompanied by a reduction in bilirubin in patients with hepatic failure. Previous studies have shown that hyperammonemia can cause bilirubin metabolism disorders, however it is unclear exactly how hyperammonemia interferes with bilirubin metabolism in hepatocytes. The purpose of the current study was to determine the mechanism or mechanisms by which hyperammonemia interferes with bilirubin metabolism in hepatocytes. Cell viability and apoptosis were analyzed in primary hepatocytes that had been exposed to ammonium chloride. Mitochondrial morphology and permeability were observed and analyzed, intermediates of the tricarboxylic acid (TCA) cycle were determined and changes in the expression of enzymes related to bilirubin metabolism were analyzed after ammonia exposure. Hyperammonemia inhibited cell growth, induced apoptosis, damaged the mitochondria and hindered the TCA cycle in hepatocytes. This led to a reduction in energy synthesis, eventually affecting the expression of enzymes related to bilirubin metabolism, which then caused further problems with bilirubin metabolism. These effects were significant, but could be reversed with the addition of adenosine triphosphate (ATP). This study demonstrates that ammonia can cause problems with bilirubin metabolism by interfering with energy synthesis.

  11. Symptomatic and silent myocardial ischaemia in hypertensive patients with left ventricular hypertrophy.

    PubMed Central

    Pringle, S D; Dunn, F G; Tweddel, A C; Martin, W; Macfarlane, P W; McKillop, J H; Lorimer, A R; Cobbe, S M

    1992-01-01

    OBJECTIVE--To assess the prevalence of symptomatic and silent myocardial ischaemia in patients with hypertensive left ventricular hypertrophy. DESIGN--Cross sectional study. SETTING--University department of medical cardiology. PATIENTS--90 patients (68 men and 22 women; mean age 57 (range 25 to 79)) with left ventricular hypertrophy due to essential hypertension. INTERVENTIONS--48 hour ambulatory ST segment monitoring (all patients), exercise electrocardiography (n = 79), stress thallium scintigraphy (n = 80), coronary arteriography (n = 35). RESULTS--43 patients had at least one episode of ST segment depression on ambulatory electrocardiographic monitoring. The median number of episodes was 16 (range 1 to 84) with a median duration of 8.6 (range 2 to 17) min. Over 90% of these episodes were clinically silent. 26 patients had positive exercise electrocardiography and 48 patients had reversible thallium perfusion defects despite chest pain during exercise in only five patients. 18 of the 35 patients who had coronary arteriography had important coronary artery disease. Seven of these patients gave no history of chest pain. CONCLUSIONS--Symptomatic and silent myocardial ischaemia are common in hypertensive patients with left ventricular hypertrophy, even in the absence of epicardial coronary artery disease. PMID:1389717

  12. Pathophysiologic assessment of left ventricular hypertrophy and strain in asymptomatic patients with essential hypertension

    SciTech Connect

    Pringle, S.D.; Macfarlane, P.W.; McKillop, J.H.; Lorimer, A.R.; Dunn, F.G.

    1989-05-01

    To investigate the significance of the electrocardiographic (ECG) pattern of left ventricular hypertrophy and strain, two groups of asymptomatic patients with essential hypertension were compared. The patients were similar in terms of age, smoking habit, serum cholesterol and blood pressure levels, but differed in the presence (Group I, n = 23) or absence (Group II, n = 23) of the ECG pattern of left ventricular hypertrophy and strain. Group I patients had significantly more episodes of exercise-induced ST segment depression (14 versus 4, p less than 0.05) and reversible thallium perfusion abnormalities (11 of 23 versus 3 of 23, p less than 0.05) despite similar exercise capacity and absence of chest pain. Nonsustained ventricular tachycardia was detected on 24 h ambulatory ECG monitoring in two patients in Group I, but no patient in Group II. Coronary arteriography performed in 20 Group I patients demonstrated significant coronary artery disease in 8 patients. This study has shown that there is a subgroup of hypertensive patients with ECG left ventricular hypertrophy and strain who have covert coronary artery disease. This can be detected by thallium perfusion scintigraphy, and may contribute to the increased risk known to be associated with this ECG abnormality.

  13. Flavonoids Extraction from Propolis Attenuates Pathological Cardiac Hypertrophy through PI3K/AKT Signaling Pathway

    PubMed Central

    Sun, Guang-wei; Qiu, Zhi-dong; Wang, Wei-nan; Sui, Xin

    2016-01-01

    Propolis, a traditional medicine, has been widely used for a thousand years as an anti-inflammatory and antioxidant drug. The flavonoid fraction is the main active component of propolis, which possesses a wide range of biological activities, including activities related to heart disease. However, the role of the flavonoids extraction from propolis (FP) in heart disease remains unknown. This study shows that FP could attenuate ISO-induced pathological cardiac hypertrophy (PCH) and heart failure in mice. The effect of the two fetal cardiac genes, atrial natriuretic factor (ANF) and β-myosin heavy chain (β-MHC), on PCH was reversed by FP. Echocardiography analysis revealed cardiac ventricular dilation and contractile dysfunction in ISO-treated mice. This finding is consistent with the increased heart weight and cardiac ANF protein levels, massive replacement fibrosis, and myocardial apoptosis. However, pretreatment of mice with FP could attenuate cardiac dysfunction and hypertrophy in vivo. Furthermore, the cardiac protection of FP was suppressed by the pan-PI3K inhibitor wortmannin. FP is a novel cardioprotective agent that can attenuate adverse cardiac dysfunction, hypertrophy, and associated disorder, such as fibrosis. The effects may be closely correlated with PI3K/AKT signaling. FP may be clinically used to inhibit PCH progression and heart failure. PMID:27213000

  14. High fructose causes cardiac hypertrophy via mitochondrial signaling pathway

    PubMed Central

    Zhang, Yan-Bo; Meng, Yan-Hai; Chang, Shuo; Zhang, Rong-Yuan; Shi, Chen

    2016-01-01

    High fructose diet can cause cardiac hypertrophy and oxidative stress is a key mediator for myocardial hypertrophy. Disruption of cystic fibrosis transmembrane conductance regulator (CFTR) leads to oxidative stress. This study aims to reveal mitochondrial oxidative stress-related signaling pathway in high fructose-induced cardiac hypertrophy. Mice were fed high fructose to develop cardiac hypertrophy. Fructose and H2O2 were used to induce cardiomyocyte hypertrophy in vitro. Mitochondria-targeted antioxidant SkQ1 was applied to investigate the possible role of mitochondrial reactive oxygen species (ROS). CFTR silence was performed to detect the role of CFTR in high fructose-induced myocardial hypertrophy. ROS, glutathione (GSH), mitochondrial function and hypertrophic markers were measured. We confirmed that long-term high fructose diet caused cardiac hypertrophy and diastolic dysfunction and elevated mitochondrial ROS. However, SkQ1 administration prevented heart hypertrophy and mitochondrial oxidative stress. Cadiomyocytes incubated with fructose or H2O2 exhibited significantly increased cell areas but SkQ1 treatment ameliorated cardiomyocyte hypertrophy induced by high fructose or H2O2 in vitro. Those results revealed that the underlying mechanism for high fructose-induced heart hypertrophy was attributed to mitochondrial oxidative stress. Moreover, CFTR expression was decreased by high fructose intervention and CFTR silence resulted in an increase in mitochondrial ROS, which suggested high fructose diet affected mitochondrial oxidative stress by regulating CFTR expression. Electron transport chain impairment might be related to mitochondrial oxidative damage. In conclusion, our findings indicated that mitochondrial oxidative stress plays a central role in pathogenesis of high fructose-induced cardiac hypertrophy. High fructose decreases CFTR expression to regulate mitochondrial oxidative stress. PMID:27904687

  15. Hydrophobic motif site-phosphorylated protein kinase CβII between mTORC2 and Akt regulates high glucose-induced mesangial cell hypertrophy.

    PubMed

    Das, Falguni; Ghosh-Choudhury, Nandini; Mariappan, Meenalakshmi M; Kasinath, Balakuntalam S; Choudhury, Goutam Ghosh

    2016-04-01

    PKCβII controls the pathologic features of diabetic nephropathy, including glomerular mesangial cell hypertrophy. PKCβII contains the COOH-terminal hydrophobic motif site Ser-660. Whether this hydrophobic motif phosphorylation contributes to high glucose-induced mesangial cell hypertrophy has not been determined. Here we show that, in mesangial cells, high glucose increased phosphorylation of PKCβII at Ser-660 in a phosphatidylinositol 3-kinase (PI3-kinase)-dependent manner. Using siRNAs to downregulate PKCβII, dominant negative PKCβII, and PKCβII hydrophobic motif phosphorylation-deficient mutant, we found that PKCβII regulates activation of mechanistic target of rapamycin complex 1 (mTORC1) and mesangial cell hypertrophy by high glucose. PKCβII via its phosphorylation at Ser-660 regulated phosphorylation of Akt at both catalytic loop and hydrophobic motif sites, resulting in phosphorylation and inactivation of its substrate PRAS40. Specific inhibition of mTORC2 increased mTORC1 activity and induced mesangial cell hypertrophy. In contrast, inhibition of mTORC2 decreased the phosphorylation of PKCβII and Akt, leading to inhibition of PRAS40 phosphorylation and mTORC1 activity and prevented mesangial cell hypertrophy in response to high glucose; expression of constitutively active Akt or mTORC1 restored mesangial cell hypertrophy. Moreover, constitutively active PKCβII reversed the inhibition of high glucose-stimulated Akt phosphorylation and mesangial cell hypertrophy induced by suppression of mTORC2. Finally, using renal cortexes from type 1 diabetic mice, we found that increased phosphorylation of PKCβII at Ser-660 was associated with enhanced Akt phosphorylation and mTORC1 activation. Collectively, our findings identify a signaling route connecting PI3-kinase to mTORC2 to phosphorylate PKCβII at the hydrophobic motif site necessary for Akt phosphorylation and mTORC1 activation, leading to mesangial cell hypertrophy.

  16. Metabolic switch and hypertrophy of cardiomyocytes following treatment with angiotensin II are prevented by AMP-activated protein kinase.

    PubMed

    Stuck, Bettina Johanna; Lenski, Matthias; Böhm, Michael; Laufs, Ulrich

    2008-11-21

    Angiotensin II induces cardiomyocyte hypertrophy, but its consequences on cardiomyocyte metabolism and energy supply are not completely understood. Here we investigate the effect of angiotensin II on glucose and fatty acid utilization and the modifying role of AMP-activated protein kinase (AMPK), a key regulator of metabolism and proliferation. Treatment of H9C2 cardiomyocytes with angiotensin II (Ang II, 1 microm, 4 h) increased [(3)H]leucine incorporation, up-regulated the mRNA expression of the hypertrophy marker genes MLC, ANF, BNP, and beta-MHC, and decreased the phosphorylation of the negative mTOR-regulator tuberin (TSC-2). Rat neonatal cardiomyocytes showed similar results. Western blot analysis revealed a time- and concentration-dependent down-regulation of AMPK-phosphorylation in the presence of angiotensin II, whereas the protein expression of the catalytic alpha-subunit remained unchanged. This was paralleled by membrane translocation of glucose-transporter type 4 (GLUT4), increased uptake of [(3)H]glucose and transient down-regulation of phosphorylation of acetyl-CoA carboxylase (ACC), whereas fatty acid uptake remained unchanged. Similarly, short-term transaortic constriction in mice resulted in down-regulation of P-AMPK and P-ACC but up-regulation of GLUT4 membrane translocation in the heart. Preincubation of cardiomyocytes with the AMPK stimulator 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR; 1 mM, 4 h) completely prevented the angiotensin II-induced cardiomyocytes hypertrophy. In addition, AICAR reversed the metabolic effects of angiotensin II: GLUT4 translocation was reduced, but ACC phosphorylation and TSC phosphorylation were elevated. In summary, angiotensin II-induced hypertrophy of cardiomyocytes is accompanied by decreased activation of AMPK, increased glucose uptake, and decreased mTOR inhibition. Stimulation with the AMPK activator AICAR reverses these metabolic changes, increases fatty acid utilization, and inhibits

  17. Left ventricular hypertrophy in athletes and hypertensive patients.

    PubMed

    Lovic, Dragan; Narayan, Puneet; Pittaras, Andreas; Faselis, Charles; Doumas, Michael; Kokkinos, Peter

    2017-04-01

    Systemic hypertension and physical exercise are both associated with cardiac adaptations. The impact is most prominent on the left side of the heart, which hypertrophies leading to left ventricular hypertrophy. This article reviews structural and functional cardiac changes seen in hypertensive and athlete's hearts.

  18. FGF23 induces left ventricular hypertrophy

    PubMed Central

    Faul, Christian; Amaral, Ansel P.; Oskouei, Behzad; Hu, Ming-Chang; Sloan, Alexis; Isakova, Tamara; Gutiérrez, Orlando M.; Aguillon-Prada, Robier; Lincoln, Joy; Hare, Joshua M.; Mundel, Peter; Morales, Azorides; Scialla, Julia; Fischer, Michael; Soliman, Elsayed Z.; Chen, Jing; Go, Alan S.; Rosas, Sylvia E.; Nessel, Lisa; Townsend, Raymond R.; Feldman, Harold I.; St. John Sutton, Martin; Ojo, Akinlolu; Gadegbeku, Crystal; Di Marco, Giovana Seno; Reuter, Stefan; Kentrup, Dominik; Tiemann, Klaus; Brand, Marcus; Hill, Joseph A.; Moe, Orson W.; Kuro-o, Makoto; Kusek, John W.; Keane, Martin G.; Wolf, Myles

    2011-01-01

    Chronic kidney disease (CKD) is a public health epidemic that increases risk of death due to cardiovascular disease. Left ventricular hypertrophy (LVH) is an important mechanism of cardiovascular disease in individuals with CKD. Elevated levels of FGF23 have been linked to greater risks of LVH and mortality in patients with CKD, but whether these risks represent causal effects of FGF23 is unknown. Here, we report that elevated FGF23 levels are independently associated with LVH in a large, racially diverse CKD cohort. FGF23 caused pathological hypertrophy of isolated rat cardiomyocytes via FGF receptor–dependent activation of the calcineurin-NFAT signaling pathway, but this effect was independent of klotho, the coreceptor for FGF23 in the kidney and parathyroid glands. Intramyocardial or intravenous injection of FGF23 in wild-type mice resulted in LVH, and klotho-deficient mice demonstrated elevated FGF23 levels and LVH. In an established animal model of CKD, treatment with an FGF–receptor blocker attenuated LVH, although no change in blood pressure was observed. These results unveil a klotho-independent, causal role for FGF23 in the pathogenesis of LVH and suggest that chronically elevated FGF23 levels contribute directly to high rates of LVH and mortality in individuals with CKD. PMID:21985788

  19. Glucose Transporters in Cardiac Metabolism and Hypertrophy

    PubMed Central

    Shao, Dan; Tian, Rong

    2016-01-01

    The heart is adapted to utilize all classes of substrates to meet the high-energy demand, and it tightly regulates its substrate utilization in response to environmental changes. Although fatty acids are known as the predominant fuel for the adult heart at resting stage, the heart switches its substrate preference toward glucose during stress conditions such as ischemia and pathological hypertrophy. Notably, increasing evidence suggests that the loss of metabolic flexibility associated with increased reliance on glucose utilization contribute to the development of cardiac dysfunction. The changes in glucose metabolism in hypertrophied hearts include altered glucose transport and increased glycolysis. Despite the role of glucose as an energy source, changes in other nonenergy producing pathways related to glucose metabolism, such as hexosamine biosynthetic pathway and pentose phosphate pathway, are also observed in the diseased hearts. This article summarizes the current knowledge regarding the regulation of glucose transporter expression and translocation in the heart during physiological and pathological conditions. It also discusses the signaling mechanisms governing glucose uptake in cardiomyocytes, as well as the changes of cardiac glucose metabolism under disease conditions. PMID:26756635

  20. Hepatocyte Growth Factor Reduces Free Cholesterol-Mediated Lipotoxicity in Primary Hepatocytes by Countering Oxidative Stress.

    PubMed

    Domínguez-Pérez, Mayra; Nuño-Lámbarri, Natalia; Clavijo-Cornejo, Denise; Luna-López, Armando; Souza, Verónica; Bucio, Leticia; Miranda, Roxana U; Muñoz, Linda; Gomez-Quiroz, Luis Enrique; Uribe-Carvajal, Salvador; Gutiérrez-Ruiz, María Concepción

    2016-01-01

    Cholesterol overload in the liver has shown toxic effects by inducing the aggravation of nonalcoholic fatty liver disease to steatohepatitis and sensitizing to damage. Although the mechanism of damage is complex, it has been demonstrated that oxidative stress plays a prominent role in the process. In addition, we have proved that hepatocyte growth factor induces an antioxidant response in hepatic cells; in the present work we aimed to figure out the protective effect of this growth factor in hepatocytes overloaded with free cholesterol. Hepatocytes from mice fed with a high-cholesterol diet were treated or not with HGF, reactive oxygen species present in cholesterol overloaded hepatocytes significantly decreased, and this effect was particularly associated with the increase in glutathione and related enzymes, such as γ-gamma glutamyl cysteine synthetase, GSH peroxidase, and GSH-S-transferase. Our data clearly indicate that HGF displays an antioxidant response by inducing the glutathione-related protection system.

  1. Hepatocyte Growth Factor Reduces Free Cholesterol-Mediated Lipotoxicity in Primary Hepatocytes by Countering Oxidative Stress

    PubMed Central

    Domínguez-Pérez, Mayra; Nuño-Lámbarri, Natalia; Clavijo-Cornejo, Denise; Luna-López, Armando; Souza, Verónica; Bucio, Leticia; Miranda, Roxana U.; Muñoz, Linda; Gomez-Quiroz, Luis Enrique; Uribe-Carvajal, Salvador; Gutiérrez-Ruiz, María Concepción

    2016-01-01

    Cholesterol overload in the liver has shown toxic effects by inducing the aggravation of nonalcoholic fatty liver disease to steatohepatitis and sensitizing to damage. Although the mechanism of damage is complex, it has been demonstrated that oxidative stress plays a prominent role in the process. In addition, we have proved that hepatocyte growth factor induces an antioxidant response in hepatic cells; in the present work we aimed to figure out the protective effect of this growth factor in hepatocytes overloaded with free cholesterol. Hepatocytes from mice fed with a high-cholesterol diet were treated or not with HGF, reactive oxygen species present in cholesterol overloaded hepatocytes significantly decreased, and this effect was particularly associated with the increase in glutathione and related enzymes, such as γ-gamma glutamyl cysteine synthetase, GSH peroxidase, and GSH-S-transferase. Our data clearly indicate that HGF displays an antioxidant response by inducing the glutathione-related protection system. PMID:27143995

  2. Increased Expression of Hepatocyte Nuclear Factor 6 Stimulates Hepatocyte Proliferation during Mouse Liver Regeneration

    PubMed Central

    Tan, Yongjun; Yoshida, Yuichi; Hughes, Douglas E.; Costa, Robert H.

    2005-01-01

    Background & Aims The Hepatocyte Nuclear Factor 6 (HNF6 or ONECUT-1) protein is a cell-type specific transcription factor that regulates expression of hepatocyte-specific genes. Using hepatocytes for Chromatin Immunoprecipitation (ChIP) assays, the HNF6 protein was shown to associate with cell cycle regulatory promoters. Here, we examined whether increased levels of HNF6 stimulate hepatocyte proliferation during mouse liver regeneration. Methods Tail vein injection of adenovirus expressing the HNF6 cDNA (AdHNF6) was used to increase hepatic HNF6 levels during mouse liver regeneration induced by partial hepatectomy, and DNA replication was determined by Bromodeoxyuridine incorporation. Cotransfection and ChIP assays were used to determine transcriptional target promoters. Results Elevated expression of HNF6 during mouse liver regeneration causes a significant increase in the number of hepatocytes entering DNA replication (S-phase) and mouse hepatoma Hepa1-6 cells diminished for HNF6 levels by siRNA transfection exhibit a 50% reduction in S-phase following serum stimulation. This stimulation in hepatocyte S-phase progression was associated with increased expression of the hepatocyte mitogen Tumor Growth Factor α (TGFα) and the cell cycle regulators Cyclin D1 and Forkhead Box m1 (Foxm1) transcription factor. Cotransfection and ChIP assays show that TGFα, Cyclin D1, and HNF6 promoter regions are direct transcriptional targets of the HNF6 protein. Co-immunoprecipitation assays with regenerating mouse liver extracts reveal association between HNF6 and Foxm1 proteins and cotransfection assays show that HNF6 stimulates Foxm1 transcriptional activity. Conclusion These mouse liver regeneration studies show that increased HNF6 levels stimulate hepatocyte proliferation through transcriptional induction of cell cycle regulatory genes. PMID:16618419

  3. Constrained spheroids for prolonged hepatocyte culture.

    PubMed

    Tong, Wen Hao; Fang, Yu; Yan, Jie; Hong, Xin; Hari Singh, Nisha; Wang, Shu Rui; Nugraha, Bramasta; Xia, Lei; Fong, Eliza Li Shan; Iliescu, Ciprian; Yu, Hanry

    2016-02-01

    Liver-specific functions in primary hepatocytes can be maintained over extended duration in vitro using spheroid culture. However, the undesired loss of cells over time is still a major unaddressed problem, which consequently generates large variations in downstream assays such as drug screening. In static culture, the turbulence generated by medium change can cause spheroids to detach from the culture substrate. Under perfusion, the momentum generated by Stokes force similarly results in spheroid detachment. To overcome this problem, we developed a Constrained Spheroids (CS) culture system that immobilizes spheroids between a glass coverslip and an ultra-thin porous Parylene C membrane, both surface-modified with poly(ethylene glycol) and galactose ligands for optimum spheroid formation and maintenance. In this configuration, cell loss was minimized even when perfusion was introduced. When compared to the standard collagen sandwich model, hepatocytes cultured as CS under perfusion exhibited significantly enhanced hepatocyte functions such as urea secretion, and CYP1A1 and CYP3A2 metabolic activity. We propose the use of the CS culture as an improved culture platform to current hepatocyte spheroid-based culture systems.

  4. Targeted transplantation of mitochondria to hepatocytes

    PubMed Central

    Gupta, Nidhi; Wu, Catherine H; Wu, George Y

    2016-01-01

    Background Mitochondrial defects in hepatocytes can result in liver dysfunction and death. Hepatocytes have cell-surface asialoglycoprotein receptors (AsGRs) which internalize AsGs within endosomes. The aim of this study was to determine whether mitochondria could be targeted to hepatocytes by AsGR-mediated endocytosis. Materials and methods An AsG, AsOR, was linked to polylysine to create a conjugate, AsOR-PL, and complexed with healthy and functional mitochondria (defined by normal morphology, cytochrome c assays, and oxygen-consumption rates). Huh7 (AsGR+) and SK Hep1 (AsGR−) cells were treated with a mitochondrial toxin to form Huh7-Mito− and SK Hep1-Mito− cells, lacking detectable mitochondrial DNA. An endosomolytic peptide, LLO, was coupled to AsOR to form AsOR-LLO. A lysosomal inhibitor, amantadine, was used in mitochondria-uptake studies as a control for nonspecific endosomal release. Results Coincubation of complexed mitochondria and AsOR-LLO with Huh7-Mito− cells increased mitochondrial DNA to >9,700-fold over control at 7 days (P<0.001), and increased mitochondrial oxygen-consumption rates to >90% of control by 10 days. Conclusion Rescue of mitochondria-damaged hepatocytes can be achieved by targeted uptake of normal mitochondria through receptor-mediated endocytosis. PMID:27942238

  5. Neurogenic muscle hypertrophy in a 12-year-old girl.

    PubMed

    Zutelija Fattorini, Matija; Gagro, Alenka; Dapic, Tomislav; Krakar, Goran; Marjanovic, Josip

    2017-01-01

    Muscular hypertrophy secondary to denervation is very rare, but well-documented phenomena in adults. This is the first report of a child with neurogenic unilateral hypertrophy due to S1 radiculopathy. A 12-year-old girl presented with left calf hypertrophy and negative history of low back pain or trauma. The serum creatinine kinase level and inflammatory markers were normal. Magnetic resonance imaging showed muscle hypertrophy of the left gastrocnemius and revealed a protruded lumbar disc at the L5-S1 level. The protruded disc abuts the S1 root on the left side. Electromyography showed mild left S1 radiculopathy. Passive stretching and work load might clarify the origin of neurogenic hypertrophy but there is still a need for further evidence. Clinical, laboratory, magnetic resonance imaging and electromyography findings showed that S1 radiculopathy could be a cause of unilateral calf swelling in youth even in the absence of a history of back or leg pain.

  6. Human Cord Blood Stem Cells Generate Human Cytokeratin 18-Negative Hepatocyte-Like Cells in Injured Mouse Liver

    PubMed Central

    Sharma, Amar Deep; Cantz, Tobias; Richter, Rudolf; Eckert, Klaus; Henschler, Reinhard; Wilkens, Ludwig; Jochheim-Richter, Andrea; Arseniev, Lubomir; Ott, Michael

    2005-01-01

    Differentiation of adult bone marrow (BM) cells into nonhematopoietic cells is a rare phenomenon. Several reports, however, suggest that human umbilical cord blood (hUCB)-derived cells give rise to hepatocytes after transplantation into nonobese diabetic-severe combined immunodeficient (NOD-SCID) mice. Therefore, we analyzed the hepatic differentiation potential of hUCB cells and compared the frequency of newly formed hepatocyte-like cells in the livers of recipient NOD-SCID mice after transplantation of hUCB versus murine BM cells. Mononuclear cell preparations of hUCB cells or murine BM from enhanced green fluorescent protein transgenic or wild-type mice were transplanted into sublethally irradiated NOD-SCID mice. Liver regeneration was induced by carbon tetrachloride injury with and without sub-sequent hepatocyte growth factor treatment. By immunohistochemistry and reverse transcriptasepolymerase chain reaction, we detected clusters of hepatocyte-like cells in the livers of hUCB-transplanted mice. These cells expressed human albumin and Hep Par 1 but mouse CK18, suggesting the formation of chimeric hepatocyte-like cells. Native fluorescence microscopy and double immunofluorescence failed to detect single hepatocytes derived from transplanted enhanced green fluorescent protein-transgenic mouse BM. Fluorescent in situ hybridization rarely revealed donor-derived hepatocyte-like cells after cross-gender mouse BM transplantation. Thus, hUCB cells have differentiation capabilities different from murine BM cells after transplantation into NOD-SCID mice, demonstrating the importance of further testing before hUCB cells can be used therapeutically. PMID:16049339

  7. Sry HMG box protein 9-positive (Sox9+) epithelial cell adhesion molecule-negative (EpCAM-) biphenotypic cells derived from hepatocytes are involved in mouse liver regeneration.

    PubMed

    Tanimizu, Naoki; Nishikawa, Yuji; Ichinohe, Norihisa; Akiyama, Haruhiko; Mitaka, Toshihiro

    2014-03-14

    It has been shown that mature hepatocytes compensate tissue damages not only by proliferation and/or hypertrophy but also by conversion into cholangiocyte-like cells. We found that Sry HMG box protein 9-positive (Sox9(+)) epithelial cell adhesion molecule-negative (EpCAM(-)) hepatocyte nuclear factor 4α-positive (HNF4α(+)) biphenotypic cells showing hepatocytic morphology appeared near EpCAM(+) ductular structures in the livers of mice fed 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-containing diet. When Mx1-Cre:ROSA mice, which were injected with poly(I:C) to label mature hepatocytes, were fed with the DDC diet, we found LacZ(+)Sox9(+) cells near ductular structures. Although Sox9(+)EpCAM(-) cells adjacent to expanding ducts likely further converted into ductular cells, the incidence was rare. To know the cellular characteristics of Sox9(+)EpCAM(-) cells, we isolated them as GFP(+)EpCAM(-) cells from DDC-injured livers of Sox9-EGFP mice. Sox9(+)EpCAM(-) cells proliferated and could differentiate to functional hepatocytes in vitro. In addition, Sox9(+)EpCAM(-) cells formed cysts with a small central lumen in collagen gels containing Matrigel® without expressing EpCAM. These results suggest that Sox9(+)EpCAM(-) cells maintaining biphenotypic status can establish cholangiocyte-type polarity. Interestingly, we found that some of the Sox9(+) cells surrounded luminal spaces in DDC-injured liver while they expressed HNF4α. Taken together, we consider that in addition to converting to cholangiocyte-like cells, Sox9(+)EpCAM(-) cells provide luminal space near expanded ductular structures to prevent deterioration of the injuries and potentially supply new hepatocytes to repair damaged tissues.

  8. Sry HMG Box Protein 9-positive (Sox9+) Epithelial Cell Adhesion Molecule-negative (EpCAM−) Biphenotypic Cells Derived from Hepatocytes Are Involved in Mouse Liver Regeneration*

    PubMed Central

    Tanimizu, Naoki; Nishikawa, Yuji; Ichinohe, Norihisa; Akiyama, Haruhiko; Mitaka, Toshihiro

    2014-01-01

    It has been shown that mature hepatocytes compensate tissue damages not only by proliferation and/or hypertrophy but also by conversion into cholangiocyte-like cells. We found that Sry HMG box protein 9-positive (Sox9+) epithelial cell adhesion molecule-negative (EpCAM−) hepatocyte nuclear factor 4α-positive (HNF4α+) biphenotypic cells showing hepatocytic morphology appeared near EpCAM+ ductular structures in the livers of mice fed 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-containing diet. When Mx1-Cre:ROSA mice, which were injected with poly(I:C) to label mature hepatocytes, were fed with the DDC diet, we found LacZ+Sox9+ cells near ductular structures. Although Sox9+EpCAM− cells adjacent to expanding ducts likely further converted into ductular cells, the incidence was rare. To know the cellular characteristics of Sox9+EpCAM− cells, we isolated them as GFP+EpCAM− cells from DDC-injured livers of Sox9-EGFP mice. Sox9+EpCAM− cells proliferated and could differentiate to functional hepatocytes in vitro. In addition, Sox9+EpCAM− cells formed cysts with a small central lumen in collagen gels containing Matrigel® without expressing EpCAM. These results suggest that Sox9+EpCAM− cells maintaining biphenotypic status can establish cholangiocyte-type polarity. Interestingly, we found that some of the Sox9+ cells surrounded luminal spaces in DDC-injured liver while they expressed HNF4α. Taken together, we consider that in addition to converting to cholangiocyte-like cells, Sox9+EpCAM− cells provide luminal space near expanded ductular structures to prevent deterioration of the injuries and potentially supply new hepatocytes to repair damaged tissues. PMID:24482234

  9. Sustained endoplasmic reticulum stress inhibits hepatocyte proliferation via downregulation of c-Met expression.

    PubMed

    He, Yihuai; Long, Jun; Zhong, Weiwei; Fu, Yu; Li, Ying; Lin, Shide

    2014-04-01

    The molecular mechanisms of impaired liver regeneration in several liver diseases remain poorly understood. Endoplasmic reticulum (ER) stress has been observed in a variety of liver diseases. The aims of this study were to explore the impacts of ER stress on hepatocyte growth factor (HGF)-induced proliferation and c-Met expression in human hepatocyte L02 cells. Human hepatocyte L02 cells were incubated with thapsigargin (TG) to induce ER stress. 4-Phenylbutyric acid (PBA) was used to rescue ER stress. Activation of glucose-regulated protein 78, phosphorylation of PKR-like ER kinase and eukaryotic translation initiation factor-2α, and the expression of c-Met were determined by western blotting. The expression of c-Met mRNA was observed by reverse transcription polymerase chain reaction. L02 cell proliferation was determined by the MTS assay. L02 cell proliferation was significantly impaired in TG-treated L02 cells from 24 to 48 h, while PBA partly restored the proliferation of L02 cells. In addition, TG treatment significantly decreased the sensitivity of L02 cells to HGF-induced proliferation. PBA partly resumed the sensitivity of L02 cells to HGF-induced proliferation. The expression of c-Met protein in L02 cells was downregulated from 6 h after TG treatment, and PBA partly restored c-Met expression inhibited by TG. The expression of c-Met mRNA was also significantly downregulated from 24 to 48 h after TG treatment. Our results strongly suggest that sustained ER stress inhibits hepatocyte proliferation via downregulation of both c-Met mRNA and protein expression in human hepatocyte L02 cells.

  10. Induction of mitochondrial biogenesis and respiration is associated with mTOR regulation in hepatocytes of rats treated with the pan-PPAR activator tetradecylthioacetic acid (TTA)

    SciTech Connect

    Hagland, Hanne R.; Nilsson, Linn I.H.; Burri, Lena; Nikolaisen, Julie; Berge, Rolf K.; Tronstad, Karl J.

    2013-01-11

    Highlights: Black-Right-Pointing-Pointer We investigated mechanisms of mitochondrial regulation in rat hepatocytes. Black-Right-Pointing-Pointer Tetradecylthioacetic acid (TTA) was employed to activate mitochondrial oxidation. Black-Right-Pointing-Pointer Mitochondrial biogenesis and respiration were induced. Black-Right-Pointing-Pointer It was confirmed that PPAR target genes were induced. Black-Right-Pointing-Pointer The mechanism involved activation mTOR. -- Abstract: The hypolipidemic effect of peroxisome proliferator-activated receptor (PPAR) activators has been explained by increasing mitochondrial fatty acid oxidation, as observed in livers of rats treated with the pan-PPAR activator tetradecylthioacetic acid (TTA). PPAR-activation does, however, not fully explain the metabolic adaptations observed in hepatocytes after treatment with TTA. We therefore characterized the mitochondrial effects, and linked this to signalling by the metabolic sensor, the mammalian target of rapamycin (mTOR). In hepatocytes isolated from TTA-treated rats, the changes in cellular content and morphology were consistent with hypertrophy. This was associated with induction of multiple mitochondrial biomarkers, including mitochondrial DNA, citrate synthase and mRNAs of mitochondrial proteins. Transcription analysis further confirmed activation of PPAR{alpha}-associated genes, in addition to genes related to mitochondrial biogenesis and function. Analysis of mitochondrial respiration revealed that the capacity of both electron transport and oxidative phosphorylation were increased. These effects coincided with activation of the stress related factor, ERK1/2, and mTOR. The protein level and phosphorylation of the downstream mTOR actors eIF4G and 4E-BP1 were induced. In summary, TTA increases mitochondrial respiration by inducing hypertrophy and mitochondrial biogenesis in rat hepatocytes, via adaptive regulation of PPARs as well as mTOR.

  11. Cryopreservation of primarily isolated porcine hepatocytes with UW solution.

    PubMed

    Kunieda, Takemi; Maruyama, Masanobu; Okitsu, Teru; Shibata, Norikuni; Takesue, Michihiko; Totsugawa, Toshinori; Kosaka, Yoshikazu; Arata, Takashi; Kobayashi, Kazuya; Ikeda, Hideaki; Oshita, Mizuko; Nakaji, Shuhei; Ohmoto, Kenji; Yamamoto, Shinichiro; Kurabayashi, Yuzuru; Kodama, Makoto; Tanaka, Noriaki; Kobayashi, Naoya

    2003-01-01

    Development of liver-targeted cell therapies, such as hepatocyte transplantation and bioartificial livers, requires a large amount of functional hepatocytes as needed. To achieve this development, establishing an excellent cryopreservation method of hepatocytes is an extremely important issue. Therefore, we performed a comparative review of cryoprotective effects of various cryopreservation solutions using primarily isolated porcine hepatocytes. Porcine hepatocytes were isolated with a four-step dispase and collagenase perfusion method. The obtained hepatocytes with the initial viabilities of 76%, 84%, and 96% were assigned to the following four groups for cryopreservation at -80 degrees C: Dulbecco's modified Eagle's medium (DMEM) + 10% fetal bovine serum (FBS) + 12% dimethyl sulfoxide (DMSO) (group A), University of Wisconsin (UW) solution + 12% DMSO (group B), Cell Banker 1 (group C), and Cell Banker 2 (group D). The hepatocytes in each group were thawed at 3 days, 10 days, and 5 months of cryopreservation and subjected to comparative analyses, including viability, plating efficiency, LDH release, ammonia removal test, and lentiviral gene transfer. These parameters were the most favorable in the hepatocytes cryopreserved with UW solution. Approximately 5% of thawed cryopreserved porcine hepatocytes expressed LacZ activity after lentiviral transduction. Intrasplenic transplantation of UW solution-cryopreserved hepatocytes improved the survival of rats treated with D-galactosamine. UW solution maintained the functions of cryopreserved porcine hepatocytes.

  12. Curcumin inhibits cobalt chloride-induced epithelial-to-mesenchymal transition associated with interference with TGF-β/Smad signaling in hepatocytes.

    PubMed

    Kong, Desong; Zhang, Feng; Shao, Jiangjuan; Wu, Li; Zhang, Xiaoping; Chen, Li; Lu, Yin; Zheng, Shizhong

    2015-11-01

    Epithelial-mesenchymal transition (EMT) occurs during adult tissue remodeling responses including carcinogenesis and fibrosis. Existing evidence reveals that hepatocytes can undergo EMT in adult liver, which is critically involved in chronic liver injury. We herein established a hypoxia-induced EMT model in human LO2 hepatocytes treated with cobalt chloride (CoCl2) in vitro, and evaluated the effects of curcumin, a natural antifibrotic compound, on hepatocyte EMT and explored the underlying molecular mechanisms. We found that CoCl2 at non-toxic doses induced a mesenchymal cell phenotype in hepatocytes and upregulated several mesenchymal markers including α-smooth muscle actin, vimentin, N-cadherin, fibronectin and Snail (an EMT-related transcription factor), but downregulated the epithelial marker E-cadherin in hepatocytes. However, curcumin reversed the morphological changes, abrogated the increased expression of mesenchymal markers, and rescued E-cadherin expression in CoCl2-treated hepatocytes, suggesting the inhibition of hepatocyte EMT in vitro. We further found that curcumin interfered with the transforming growth factor-β (TGF-β) signaling by reducing the expression of TGF-β receptor I and inhibiting the expression and phosphorylation of Smad2 and Smad3. Use of SB431542, a specific inhibitor of TGF-β receptor I, demonstrated that interference with the TGF-β/Smad pathway was associated with curcumin suppression of hepatocyte EMT. Our in vivo data showed that curcumin affected hepatic EMT in rat fibrotic liver caused by carbon tetrachloride, which was associated with the inhibition of TGF-β/Smad signaling. These findings characterized a novel mechanism by which curcumin modulated hepatocyte EMT implicated in treatment of liver fibrosis.

  13. Differentiation of human foreskin fibroblast-derived induced pluripotent stem cells into hepatocyte-like cells.

    PubMed

    Wang, Jianjun; Zhao, Ping; Wan, Zhihong; Jin, Xueyuan; Cheng, Yongqian; Yan, Tao; Qing, Song; Ding, Ning; Xin, Shaojie

    2016-10-01

    The aim of this study was to investigate the differentiation potential of induced pluripotent stem cells (iPSCs) derived from human foreskin fibroblasts (HFFs) into hepatocyte-like cells (HLCs). The iPSCs were firstly induced by transduction of OCT4, SOX2, KLF4, and c-MYC into HFFs using retrovirus. Afterwards, expressions of pluripotency factors were identified by semiquantitative reverse transcription-polymerase chain reaction and immunofluorescence staining, and karyotype, embryoid, and teratoma were observed by microscope. Then, iPSCs were gradually differentiated into endoderm cells, hepatic progenitor cells, and mature HLCs by special culture medium. During this process, differentiation efficiency into each kind of cells was evaluated by detecting SOX17, HNF4a, and ALB using flow cytometry, respectively. Besides, enzyme-linked immunosorbent assay was conducted to detect the secretion of ALB in iPSC-induced HLCs and quantitative reverse transcription-polymerase chain reaction was performed to detect the expression levels of hepatocyte-specific genes. The iPSCs were successfully induced by HFFs, which exhibited typical embryonic stem cells morphology, positive alkaline phosphatase staining, normal diploid karyotype, and positive expression of various pluripotency factors. Meanwhile, spherical embryoid and teratoma with 3 germ layers were formed by iPSCs. The iPSCs were consecutively induced into endoderm cells, hepatic progenitor cells and mature HLCs, and the differentiation efficiency was 55.7 ± 2.9%, 45.7 ± 4.8%, and 35.0 ± 3.9%, respectively. Besides, the secretion of ALB and expression of various hepatocyte-specific genes was highly detected in iPSC-induced HLCs. The iPSCs were successfully derived from HFFs and then differentiated into HLCs, which proved a new source for hepatocyte transplantation.

  14. [Molecular mechanisms of skeletal muscle hypertrophy].

    PubMed

    Astratenkova, I V; Rogozkin, V A

    2014-06-01

    Enzymes Akt, AMPK, mTOR, S6K and PGC-1a coactivator take part in skeletal muscles in the regulation of synthesis of proteins. The expression of these proteins is regulated by growth factors, hormones, nutrients, mechanical loading and leads to an increase in muscle mass and skeletal muscle hypertrophy. The review presents the results of studies published in the past four years, which expand knowledge on the effects of various factors on protein synthesis in skeletal muscle. The attention is focused on the achievements that reveal and clarify the signaling pathways involved in the regulation of protein synthesis in skeletal muscle. The central place is taken by mTOR enzyme which controls and regulates the main stages of the cascade of reactions of muscle proteins providing synthesis in the conditions of human life. coactivator PGC-1a.

  15. Intrinsic-mediated caspase activation is essential for cardiomyocyte hypertrophy.

    PubMed

    Putinski, Charis; Abdul-Ghani, Mohammad; Stiles, Rebecca; Brunette, Steve; Dick, Sarah A; Fernando, Pasan; Megeney, Lynn A

    2013-10-22

    Cardiomyocyte hypertrophy is the cellular response that mediates pathologic enlargement of the heart. This maladaptation is also characterized by cell behaviors that are typically associated with apoptosis, including cytoskeletal reorganization and disassembly, altered nuclear morphology, and enhanced protein synthesis/translation. Here, we investigated the requirement of apoptotic caspase pathways in mediating cardiomyocyte hypertrophy. Cardiomyocytes treated with hypertrophy agonists displayed rapid and transient activation of the intrinsic-mediated cell death pathway, characterized by elevated levels of caspase 9, followed by caspase 3 protease activity. Disruption of the intrinsic cell death pathway at multiple junctures led to a significant inhibition of cardiomyocyte hypertrophy during agonist stimulation, with a corresponding reduction in the expression of known hypertrophic markers (atrial natriuretic peptide) and transcription factor activity [myocyte enhancer factor-2, nuclear factor kappa B (NF-κB)]. Similarly, in vivo attenuation of caspase activity via adenoviral expression of the biologic effector caspase inhibitor p35 blunted cardiomyocyte hypertrophy in response to agonist stimulation. Treatment of cardiomyocytes with procaspase 3 activating compound 1, a small-molecule activator of caspase 3, resulted in a robust induction of the hypertrophy response in the absence of any agonist stimulation. These results suggest that caspase-dependent signaling is necessary and sufficient to promote cardiomyocyte hypertrophy. These results also confirm that cell death signal pathways behave as active remodeling agents in cardiomyocytes, independent of inducing an apoptosis response.

  16. Altered carnitine transport in pressure-overload hypertrophied rat hearts

    SciTech Connect

    O'Rourke, B.; Foster, K.; Reibel, D.K.

    1986-03-01

    The authors have previously observed reduced carnitine levels in hypertrophied hearts of rats subjected to aortic constriction. In an attempt to determine the mechanism for reduced myocardial carnitine content, carnitine transport was examined in isolated perfused hearts. Hearts were excised from sham-operated and aortic-constricted rats 3 weeks following surgery and perfused at 60 mm Hg aortic pressure with buffer containing various concentrations of L-/sup 14/C-carnitine. Carnitine uptake by control and hypertrophied hearts was linear throughout 30 minutes of perfusion with 40 ..mu..M carnitine. Total carnitine uptake was significantly reduced by 25% in hypertrophied hearts at each time point examined. The reduction in uptake by hypertrophied hearts was also evident when hearts were perfused with 100 or 200 ..mu..M carnitine. When 0.05 mM mersalyl acid was included in the buffer to inhibit the carrier-mediated component of transport, no difference in carnitine uptake was observed indicating that the transport of carnitine by diffusion was unaltered in the hypertrophied myocardium. Carrier-mediated carnitine uptake (total uptake - uptake by diffusion) was significantly reduced by approximately 40% in hypertrophied hearts at all concentrations examined. Thus, the reduction in carnitine content in the pressure-overload hypertrophied rat heart appears to be due to a reduction in carrier-mediated carnitine uptake by the heart.

  17. The role of satellite cells in muscle hypertrophy.

    PubMed

    Blaauw, Bert; Reggiani, Carlo

    2014-02-01

    The role of satellite cells in muscle hypertrophy has long been a debated issue. In the late 1980s it was shown that proteins remain close to the myonucleus responsible for its synthesis, giving rise to the idea of a nuclear domain. This, together with the observation that during various models of muscle hypertrophy there is an activation of the muscle stem cells, i.e. satellite cells, lead to the idea that satellite cell activation is required for muscle hypertrophy. Thus, satellite cells are not only responsible for muscle repair and regeneration, but also for hypertrophic growth. Further support for this line of thinking was obtained after studies showing that irradiation of skeletal muscle, and therefore elimination of all satellite cells, completely prevented overload-induced hypertrophy. Recently however, using different transgenic approaches, it has become clear that muscle hypertrophy can occur without a contribution of satellite cells, even though in most situations of muscle hypertrophy satellite cells are activated. In this review we will discuss the contribution of satellite cells, and other muscle-resident stem cells, to muscle hypertrophy both in mice as well as in humans.

  18. Adipocyte-specific loss of PPARγ attenuates cardiac hypertrophy

    PubMed Central

    Fang, Xi; Stroud, Matthew J.; Ouyang, Kunfu; Fang, Li; Zhang, Jianlin; Dalton, Nancy D.; Gu, Yusu; Wu, Tongbin; Peterson, Kirk L.; Huang, Hsien-Da; Wang, Nanping

    2016-01-01

    Adipose tissue is a key endocrine organ that governs systemic homeostasis. PPARγ is a master regulator of adipose tissue signaling that plays an essential role in insulin sensitivity, making it an important therapeutic target. The selective PPARγ agonist rosiglitazone (RSG) has been used to treat diabetes. However, adverse cardiovascular effects have seriously hindered its clinical application. Experimental models have revealed that PPARγ activation increases cardiac hypertrophy. RSG stimulates cardiac hypertrophy and oxidative stress in cardiomyocyte-specific PPARγ knockout mice, implying that RSG might stimulate cardiac hypertrophy independently of cardiomyocyte PPARγ. However, candidate cell types responsible for RSG-induced cardiomyocyte hypertrophy remain unexplored. Utilizing cocultures of adipocytes and cardiomyocytes, we found that stimulation of PPARγ signaling in adipocytes increased miR-200a expression and secretion. Delivery of miR-200a in adipocyte-derived exosomes to cardiomyocytes resulted in decreased TSC1 and subsequent mTOR activation, leading to cardiomyocyte hypertrophy. Treatment with an antagomir to miR-200a blunted this hypertrophic response in cardiomyocytes. In vivo, specific ablation of PPARγ in adipocytes was sufficient to blunt hypertrophy induced by RSG treatment. By delineating mechanisms by which RSG elicits cardiac hypertrophy, we have identified pathways that mediate the crosstalk between adipocytes and cardiomyocytes to regulate cardiac remodeling. PMID:27734035

  19. Autocrine expression of hepatocyte growth factor and its cytoprotective effect on hepatocyte poisoning

    PubMed Central

    He, Yong; Zhou, Jun; Dou, Ke-Feng; Chen, Yong; Yan, Qing-Guo; Li, Hai-Min

    2004-01-01

    AIM: To construct pEGFP-hepatocyte growth factor (HGF) expression vector, the to detect its expression in transfected human hepatocytes, and to investigate the influence of autocrine HGF expression on the proliferative potential and cytoprotective effects in human hepatocytes. METHODS: Human HGF cDNA was ligated to the pEGFP vector. Recombinant plasmid was transfected into human hepatocyte line QZG with liposome. Expression of HGF protein was observed by fluorescence microscopy and immunohistochemistry. Hepatic cells were collected 24, 48, and 72 h after transfection to detect the number of [3H]-TdR uptake in DNA. DNA synthesis was observed by using PCNA stain immunohistochemistry. Acute liver cell damage was induced by carbon tetrachloride. Cytoprotective effect was observed by examining the survival rate of hepatocytes and leakage of intracellular alanine transaminase (ALT) and potassium ions. RESULTS: HGF identification of pEGFP-HGF by enzyme digestion showed that HGF fragment was cloned into BamH I and Sal I sites of pEGFP-N3. Expression of GFP in transfected hepatocytes was observed with fluorescence microscopy. The [3H]-TdR uptake became 7 times as many as in the control group 96 h after transfection. After HGF transfection, the survival rate of hepatocytes poisoned by CCl4 significantly increased (83% vs 61%, P < 0.05), and the leakage of intracellular alanine transaminase and potassium ions decreased (586 nkat/L vs 1089 nkat/L, P < 0.01; and 5.59 mmol/L vs 6.02 mmol/L, P < 0.01 respectively). Culture of transfected hepatic cells promoted the proliferation of other non-transfected cells. CONCLUSION: Transfected HGF is expressed in hepatic cells and has the activity of promoting cell division and protecting hepatic cells against poisoning. PMID:15334679

  20. Hepatocyte Culture in Autologous Decellularized Spleen Matrix

    PubMed Central

    Gao, Rui; Wu, Wanquan; Xiang, Junxi; Lv, Yi; Zheng, Xinglong; Chen, Qian; Wang, Haohua; Wang, Bo; Liu, Zhengwen; Ma, Feng

    2015-01-01

    abstract Background and Aims: Using decellularized scaffold to reengineer liver tissue is a promising alternative therapy for end-stage liver diseases. Though the decellularized human liver matrix is the ideal scaffold for reconstruction of the liver theoretically, the shortage of liver donors is still an obstacle for potential clinical application. Therefore, an appropriate alternative scaffold is needed. In the present study, we used a tissue engineering approach to prepare a rat decellularized spleen matrix (DSM) and evaluate the effectiveness of this DSM for primary rat hepatocytes culture. Methods: Rat decellularized spleen matrix (DSM) was prepared by perfusion of a series of detergents through spleen vasculature. DSM was characterized by residual DNA and specific extracellular matrix distribution. Thereafter, primary rat hepatocytes were cultured in the DSM in a 3-dimensional dynamic culture system, and liver cell survival and biological functions were evaluated by comparison with 3-dimensional sandwich culture and also with cultured in decellularized liver matrix (DLM). Results: Our research found that DSM did not exhibit any cellular components, but preserved the main extracellular matrix and the intact vasculature evaluated by DNA detection, histology, immunohistochemical staining, vessel corrosion cast and upright metallurgical microscope. Moreover, the method of DSM preparation procedure was relatively simple with high success rate (100%). After seeding primary hepatocytes in DSM, the cultured hepatocytes survived inside DSM with albumin synthesis and urea secretion within 10 d. Additionally, hepatocytes in dynamic culture medium had better biological functions at day 10 than that in sandwich culture. Albumin synthesis was 85.67 ± 6.34 μg/107cell/24h in dynamic culture in DSM compared to 62.43 ± 4.59 μg/107cell/24h in sandwich culture (P < 0.01) and to 87.54 ± 5.25 μg/107cell/24h in DLM culture (P > 0.05); urea release was 32.14 ± 8.62

  1. Painful unilateral temporalis muscle enlargement: reactive masticatory muscle hypertrophy.

    PubMed

    Katsetos, Christos D; Bianchi, Michael A; Jaffery, Fizza; Koutzaki, Sirma; Zarella, Mark; Slater, Robert

    2014-06-01

    An instance of isolated unilateral temporalis muscle hypertrophy (reactive masticatory muscle hypertrophy with fiber type 1 predominance) confirmed by muscle biopsy with histochemical fiber typing and image analysis in a 62 year-old man is reported. The patient presented with bruxism and a painful swelling of the temple. Absence of asymmetry or other abnormalities of the craniofacial skeleton was confirmed by magnetic resonance imaging and cephalometric analyses. The patient achieved symptomatic improvement only after undergoing botulinum toxin injections. Muscle biopsy is key in the diagnosis of reactive masticatory muscle hypertrophy and its distinction from masticatory muscle myopathy (hypertrophic branchial myopathy) and other non-reactive causes of painful asymmetric temporalis muscle enlargement.

  2. Virginal Breast Hypertrophy and Symptomatic Treatment: A Case Report

    PubMed Central

    Menekşe, Ebru; Önel, Safa; Karateke, Faruk; Daş, Koray; Bali, İlhan; Bozkurt, Hilmi; Sözen, Selim; Özdoğan, Mehmet

    2014-01-01

    Virginal breast hypertrophy is a rare benign disease. It is characterized by rapid and excessive growth of one or two breasts during peripubertal period. There is no specific treatment algorithm, subcutaneous mastectomy and prosthesis replacement, reduction mammoplasty, medical treatment with particularly tamoxifen are all recommended in the literature. Unfortunately, all treatment methods have some disadvantages in this patient group who have not completed their sexual and physical maturation. Although these treatments are usually required, it should be noted that spontaneous remission could rarely be seen in virginal hypertrophy. We aimed to present a case of virginal hypertrophy, in whom symptomatic treatment has been used and breast growth regressed spontaneously.

  3. Assessing the therapeutic potential of lab-made hepatocytes.

    PubMed

    Rezvani, Milad; Grimm, Andrew A; Willenbring, Holger

    2016-07-01

    Hepatocyte transplantation has potential as a bridge or even alternative to whole-organ liver transplantation. Because donor livers are scarce, realizing this potential requires the development of alternative cell sources. To be therapeutically effective, surrogate hepatocytes must replicate the complex function and ability to proliferate of primary human hepatocytes. Ideally, they are also autologous to eliminate the need for immune suppression, which can have severe side effects and may not be sufficient to prevent rejection long term. In the past decade, several methods have been developed to generate hepatocytes from other readily and safely accessible somatic cells. These lab-made hepatocytes show promise in animal models of liver diseases, supporting the feasibility of autologous liver cell therapies. Here, we review recent preclinical studies exemplifying different types of lab-made hepatocytes that can potentially be used in autologous liver cell therapies. To define the therapeutic efficacy of current lab-made hepatocytes, we compare them to primary human hepatocytes, focusing on engraftment efficiency and posttransplant proliferation and function. In addition to summarizing published results, we discuss animal models and assays effective in assessing therapeutic efficacy. This analysis underscores the therapeutic potential of current lab-made hepatocytes, but also highlights deficiencies and uncertainties that need to be addressed in future studies aimed at developing liver cell therapies with lab-made hepatocytes. (Hepatology 2016;64:287-294).

  4. Experimental hepatocyte xenotransplantation--a comprehensive review of the literature.

    PubMed

    Zhou, Huidong; Liu, Hong; Ezzelarab, Mohamed; Schmelzer, Eva; Wang, Yi; Gerlach, Jörg; Gridelli, Bruno; Cooper, David K C

    2015-01-01

    Hepatocyte transplantation (Tx) is a potential therapy for certain diseases of the liver, including hepatic failure. However, there is a limited supply of human livers as a source of cells and, after isolation, human hepatocytes can be difficult to expand in culture, limiting the number available for Tx. Hepatocytes from other species, for example, the pig, have therefore emerged as a potential alternative source. We searched the literature through the end of 2014 to assess the current status of experimental research into hepatocyte xenoTx. The literature search identified 51 reports of in vivo cross-species Tx of hepatocytes in a variety of experimental models. Most studies investigated the Tx of human (n = 23) or pig (n = 19) hepatocytes. No studies explored hepatocytes from genetically engineered pigs. The spleen was the most common site of Tx (n = 23), followed by the liver (through the portal vein [n = 6]) and peritoneal cavity (n = 19). In 47 studies (92%), there was evidence of hepatocyte engraftment and function across a species barrier. The data provided by this literature search strengthen the hypothesis that xenoTx of hepatocytes is feasible and potentially successful as a clinical therapy for certain liver diseases, including hepatic failure. By excluding vascular structures, hepatocytes isolated from genetically engineered pig livers may address some of the immunological problems of xenoTx.

  5. Mitoprotective antioxidant EUK-134 stimulates fatty acid oxidation and prevents hypertrophy in H9C2 cells.

    PubMed

    Purushothaman, Sreeja; Nair, R Renuka

    2016-09-01

    Oxidative stress is an important contributory factor for the development of cardiovascular diseases like hypertension-induced hypertrophy. Mitochondrion is the major source of reactive oxygen species. Hence, protecting mitochondria from oxidative damage can be an effective therapeutic strategy for the prevention of hypertensive heart disease. Conventional antioxidants are not likely to be cardioprotective, as they cannot protect mitochondria from oxidative damage. EUK-134 is a salen-manganese complex with superoxide dismutase and catalase activity. The possible role of EUK-134, a mitoprotective antioxidant, in the prevention of hypertrophy of H9C2 cells was examined. The cells were stimulated with phenylephrine (50 μM), and hypertrophy was assessed based on cell volume and expression of brain natriuretic peptide and calcineurin. Enhanced myocardial lipid peroxidation and protein carbonyl content, accompanied by nuclear factor-kappa B gene expression, confirmed the presence of oxidative stress in hypertrophic cells. Metabolic shift was evident from reduction in the expression of medium-chain acyl-CoA dehydrogenase. Mitochondrial oxidative stress was confirmed by the reduced expression of mitochondria-specific antioxidant peroxiredoxin-3 and enhanced mitochondrial superoxide production. Compromised mitochondrial function was apparent from reduced mitochondrial membrane potential. Pretreatment with EUK-134 (10 μM) was effective in the prevention of hypertrophic changes in H9C2 cells, reduction of oxidative stress, and prevention of metabolic shift. EUK-134 treatment improved the oxidative status of mitochondria and reversed hypertrophy-induced reduction of mitochondrial membrane potential. Supplementation with EUK-134 is therefore identified as a novel approach to attenuate cardiac hypertrophy and lends scope for the development of EUK-134 as a therapeutic agent in the management of human cardiovascular disease.

  6. Hepatocyte xenotransplantation for treating liver disease.

    PubMed

    Bonavita, André Gustavo; Quaresma, Kátia; Cotta-de-Almeida, Vinícius; Pinto, Marcelo Alves; Saraiva, Roberto Magalhães; Alves, Luiz Anastácio

    2010-01-01

    The treatment of acute and chronic liver failure is still a challenge despite modern therapeutic innovations. While liver transplantation can restore liver function and improve patient survival, donor shortages limit this treatment to a small number of patients. Cellular xenotransplantation has emerged as an alternative for treating liver failure. Xenohepatocytes could be readily available in sufficient quantities to treat patients in critical condition and thereby reduce the donor shortage. The use of isolated encapsulated or non-encapsulated cells can reduce the immunorejection response. Several studies using animal models of acute or chronic liver failure have demonstrated improved survival and recovery of liver function after xenotransplantation of adult hepatocytes. Porcine liver cells are a potential source of xenohepatocytes due to similarities with human physiology and the great number of hepatocytes that can be obtained. The recent development of less immunogenic transgenic pigs, new immunosuppressive drugs, and cellular encapsulation systems represents important advances in the field of cellular xenotransplantation. In this study, we review the work carried out in animal models that deals with the advantages and limitations of hepatocyte xenotransplantation, and we propose new studies needed in this field.

  7. Fibrous Tendon Hypertrophy after Gastrocnemius Recession: A Case Report.

    PubMed

    Jastifer, James R; Coughlin, Michael J

    2016-01-01

    Surgical complications after gastrocnemius recession have been rare in published studies. We report a case of symptomatic fibrous tendon hypertrophy requiring revision surgery. Additionally, we have provided a review of the published data on the complications related to this procedure.

  8. GENE EXPRESSION ALTERATIONS OBSERVED IN PRIMARY CULTURED RAT HEPATOCYTES AFTER TREATMENT WITH CHLORINATED OR CHLORINATED AND OZONATED DRINKING WATER FROM EAST FORK LAKE, OHIO

    EPA Science Inventory

    Drinking water from East Fork Lake was spiked with iodide and bromide, disinfected with chlorine or ozone + chlorine, concentrated ~100-fold using reverse osmosis, and volatile disinfection by-products (DBPs) added back. Primary rat hepatocytes were exposed to full-strength, 1:10...

  9. Hepatocyte-stellate cell cross-talk in the liver engenders a permissive inflammatory microenvironment that drives progression in hepatocellular carcinoma.

    PubMed

    Coulouarn, Cédric; Corlu, Anne; Glaise, Denise; Guénon, Isabelle; Thorgeirsson, Snorri S; Clément, Bruno

    2012-05-15

    Many solid malignant tumors arise on a background of inflamed and/or fibrotic tissues, features that are found in more than 80% hepatocellular carcinomas (HCC). Activated hepatic stellate cells (HSC) play a critical role in fibrogenesis associated with HCC onset and progression, yet their functional impact on hepatocyte fate remains largely unexplored. Here, we used a coculture model to investigate the cross-talk between hepatocytes (human hepatoma cells) and activated human HSCs. Unsupervised genome-wide expression profiling showed that hepatocyte-HSC cross-talk is bidirectional and results in the deregulation of functionally relevant gene networks. Notably, coculturing increased the expression of proinflammatory cytokines and modified the phenotype of hepatocytes toward motile cells. Hepatocyte-HSC cross-talk also generated a permissive proangiogenic microenvironment, particularly by inducing VEGFA and matrix metalloproteinase (MMP)9 expression in HSCs. An integrative genomic analysis revealed that the expression of genes associated with hepatocyte-HSC cross-talk correlated with HCC progression in mice and was predictive of a poor prognosis and metastasis propensity in human HCCs. Interestingly, the effects of cross-talk on migration and angiogenesis were reversed by the histone deacetylase inhibitor trichostatin A. Our findings, therefore, indicate that the cross-talk between hepatoma cells and activated HSCs is an important feature of HCC progression, which may be targeted by epigenetic modulation.

  10. Raf-mediated cardiac hypertrophy in adult Drosophila.

    PubMed

    Yu, Lin; Daniels, Joseph; Glaser, Alex E; Wolf, Matthew J

    2013-07-01

    In response to stress and extracellular signals, the heart undergoes a process called cardiac hypertrophy during which cardiomyocytes increase in size. If untreated, cardiac hypertrophy can progress to overt heart failure that causes significant morbidity and mortality. The identification of molecular signals that cause or modify cardiomyopathies is necessary to understand how the normal heart progresses to cardiac hypertrophy and heart failure. Receptor tyrosine kinase (RTK) signaling is essential for normal human cardiac function, and the inhibition of RTKs can cause dilated cardiomyopathies. However, neither investigations of activated RTK signaling pathways nor the characterization of hypertrophic cardiomyopathy in the adult fly heart has been previously described. Therefore, we developed strategies using Drosophila as a model to circumvent some of the complexities associated with mammalian models of cardiovascular disease. Transgenes encoding activated EGFR(A887T), Ras85D(V12) and Ras85D(V12S35), which preferentially signal to Raf, or constitutively active human or fly Raf caused hypertrophic cardiomyopathy as determined by decreased end diastolic lumen dimensions, abnormal cardiomyocyte fiber morphology and increased heart wall thicknesses. There were no changes in cardiomyocyte cell numbers. Additionally, activated Raf also induced an increase in cardiomyocyte ploidy compared with control hearts. However, preventing increases in cardiomyocyte ploidy using fizzy-related (Fzr) RNAi did not rescue Raf-mediated cardiac hypertrophy, suggesting that Raf-mediated polyploidization is not required for cardiac hypertrophy. Similar to mammals, the cardiac-specific expression of RNAi directed against MEK or ERK rescued Raf-mediated cardiac hypertrophy. However, the cardiac-specific expression of activated ERK(D334N), which promotes hyperplasia in non-cardiac tissues, did not cause myocyte hypertrophy. These results suggest that ERK is necessary, but not sufficient, for

  11. Time course of gene expression during mouse skeletal muscle hypertrophy.

    PubMed

    Chaillou, Thomas; Lee, Jonah D; England, Jonathan H; Esser, Karyn A; McCarthy, John J

    2013-10-01

    The purpose of this study was to perform a comprehensive transcriptome analysis during skeletal muscle hypertrophy to identify signaling pathways that are operative throughout the hypertrophic response. Global gene expression patterns were determined from microarray results on days 1, 3, 5, 7, 10, and 14 during plantaris muscle hypertrophy induced by synergist ablation in adult mice. Principal component analysis and the number of differentially expressed genes (cutoffs ≥2-fold increase or ≥50% decrease compared with control muscle) revealed three gene expression patterns during overload-induced hypertrophy: early (1 day), intermediate (3, 5, and 7 days), and late (10 and 14 days) patterns. Based on the robust changes in total RNA content and in the number of differentially expressed genes, we focused our attention on the intermediate gene expression pattern. Ingenuity Pathway Analysis revealed a downregulation of genes encoding components of the branched-chain amino acid degradation pathway during hypertrophy. Among these genes, five were predicted by Ingenuity Pathway Analysis or previously shown to be regulated by the transcription factor Kruppel-like factor-15, which was also downregulated during hypertrophy. Moreover, the integrin-linked kinase signaling pathway was activated during hypertrophy, and the downregulation of muscle-specific micro-RNA-1 correlated with the upregulation of five predicted targets associated with the integrin-linked kinase pathway. In conclusion, we identified two novel pathways that may be involved in muscle hypertrophy, as well as two upstream regulators (Kruppel-like factor-15 and micro-RNA-1) that provide targets for future studies investigating the importance of these pathways in muscle hypertrophy.

  12. Experimental Mouse Model of Lumbar Ligamentum Flavum Hypertrophy

    PubMed Central

    Saito, Takeyuki; Yokota, Kazuya; Kobayakawa, Kazu; Hara, Masamitsu; Kubota, Kensuke; Harimaya, Katsumi; Kawaguchi, Kenichi; Hayashida, Mitsumasa; Matsumoto, Yoshihiro; Doi, Toshio; Shiba, Keiichiro; Nakashima, Yasuharu; Okada, Seiji

    2017-01-01

    Lumbar spinal canal stenosis (LSCS) is one of the most common spinal disorders in elderly people, with the number of LSCS patients increasing due to the aging of the population. The ligamentum flavum (LF) is a spinal ligament located in the interior of the vertebral canal, and hypertrophy of the LF, which causes the direct compression of the nerve roots and/or cauda equine, is a major cause of LSCS. Although there have been previous studies on LF hypertrophy, its pathomechanism remains unclear. The purpose of this study is to establish a relevant mouse model of LF hypertrophy and to examine disease-related factors. First, we focused on mechanical stress and developed a loading device for applying consecutive mechanical flexion-extension stress to the mouse LF. After 12 weeks of mechanical stress loading, we found that the LF thickness in the stress group was significantly increased in comparison to the control group. In addition, there were significant increases in the area of collagen fibers, the number of LF cells, and the gene expression of several fibrosis-related factors. However, in this mecnanical stress model, there was no macrophage infiltration, angiogenesis, or increase in the expression of transforming growth factor-β1 (TGF-β1), which are characteristic features of LF hypertrophy in LSCS patients. We therefore examined the influence of infiltrating macrophages on LF hypertrophy. After inducing macrophage infiltration by micro-injury to the mouse LF, we found excessive collagen synthesis in the injured site with the increased TGF-β1 expression at 2 weeks after injury, and further confirmed LF hypertrophy at 6 weeks after injury. Our findings demonstrate that mechanical stress is a causative factor for LF hypertrophy and strongly suggest the importance of macrophage infiltration in the progression of LF hypertrophy via the stimulation of collagen production. PMID:28060908

  13. Cytoskeletal Role in the Contractile Dysfunction of Hypertrophied Myocardium

    NASA Astrophysics Data System (ADS)

    Tsutsui, Hiroyuki; Ishihara, Kazuaki; Cooper, George

    1993-04-01

    Cardiac hypertrophy in response to systolic pressure loading frequently results in contractile dysfunction of unknown cause. In the present study, pressure loading increased the microtubule component of the cardiac muscle cell cytoskeleton, which was responsible for the cellular contractile dysfunction observed. The linked microtubule and contractile abnormalities were persistent and thus may have significance for the deterioration of initially compensatory cardiac hypertrophy into congestive heart failure.

  14. Cucurbitacin B Protects Against Pressure Overload Induced Cardiac Hypertrophy.

    PubMed

    Xiao, Yang; Yang, Zheng; Wu, Qing-Qing; Jiang, Xiao-Han; Yuan, Yuan; Chang, Wei; Bian, Zhou Yan; Zhu, Jin Xiu; Tang, Qi-Zhu

    2017-04-08

    Lack of effective anti-cardiac hypertrophy drugs creates a major cause for the increasing prevalence of heart failure. In the present study, we determined the anti-hypertrophy and anti-fibrosis potential of a natural plant triterpenoid, Cucurbitacin B both in vitro and in vivo. Aortic banding (AB) was performed to induce cardiac hypertrophy. After 1 week of surgery, mice were receive cucurbitacin B treatment (Gavage, 0.2 mg/kg body weight/2 day). Afer 4 weeks of AB, cucurbitacin B demonstrated a strong anti- hypertrophy and anti-fibrosis ability as evidenced by decreased of heart weight, myocardial cell cross-sectional area and interstitial fibrosis, ameliorated of systolic and diastolic abnormalities, normalized in gene expression of hypertrophic and fibrotic markers, reserved microvascular density in pressure overload induced hypertrophic mice. Cucurbitacin B also showed significant hypertrophy inhibitory effect in phenylephrine stimulated cardiomyocytes. The Cucurbitacin B-mediated mitigated cardiac hypertrophy was attributable to the increasing level of autophagy, which was associated with the blockade of Akt/mTOR/FoxO3a signal pathway, validated by SC79, MK2206, and 3-MA, the Akt agonist, inhibitor and autophagy inhibitor in vitro. The overexpression of constitutively active Akt completely abolished the Cucurbitacin B-mediated protection of cardiac hypertrophy in human cardiomyocytes AC16. Collectively, our findings suggest that cucurbitacin B protects against cardiac hypertrophy through increasing the autophagy level in cardiomyocytes, which is associated with the inhibition of Akt/mTOR/FoxO3a signal axis. This article is protected by copyright. All rights reserved.

  15. Bezafibrate Attenuates Pressure Overload-Induced Cardiac Hypertrophy and Fibrosis

    PubMed Central

    Xu, Si-Chi; Ma, Zhen-Guo; Wei, Wen-Ying; Yuan, Yu-Pei

    2017-01-01

    Background. Peroxisome proliferator-activated receptor-α (PPAR-α) is closely associated with the development of cardiac hypertrophy. Previous studies have indicated that bezafibrate (BZA), a PPAR-α agonist, could attenuate insulin resistance and obesity. This study was designed to determine whether BZA could protect against pressure overload-induced cardiac hypertrophy. Methods. Mice were orally given BZA (100 mg/kg) for 7 weeks beginning 1 week after aortic banding (AB) surgery. Cardiac hypertrophy was assessed based on echocardiographic, histological, and molecular aspects. Moreover, neonatal rat ventricular cardiomyocytes (NRVMs) were used to investigate the effects of BZA on the cardiomyocyte hypertrophic response in vitro. Results. Our study demonstrated that BZA could alleviate cardiac hypertrophy and fibrosis in mice subjected to AB surgery. BZA treatment also reduced the phosphorylation of protein kinase B (AKT)/glycogen synthase kinase-3β (GSK3β) and mitogen-activated protein kinases (MAPKs). BZA suppressed phenylephrine- (PE-) induced hypertrophy of cardiomyocyte in vitro. The protective effects of BZA were abolished by the treatment of the PPAR-α antagonist in vitro. Conclusions. BZA could attenuate pressure overload-induced cardiac hypertrophy and fibrosis. PMID:28127304

  16. Profilin modulates sarcomeric organization and mediates cardiomyocyte hypertrophy

    PubMed Central

    Kooij, Viola; Viswanathan, Meera C.; Lee, Dong I.; Rainer, Peter P.; Schmidt, William; Kronert, William A.; Harding, Sian E.; Kass, David A.; Bernstein, Sanford I.; Van Eyk, Jennifer E.; Cammarato, Anthony

    2016-01-01

    Aims Heart failure is often preceded by cardiac hypertrophy, which is characterized by increased cell size, altered protein abundance, and actin cytoskeletal reorganization. Profilin is a well-conserved, ubiquitously expressed, multifunctional actin-binding protein, and its role in cardiomyocytes is largely unknown. Given its involvement in vascular hypertrophy, we aimed to test the hypothesis that profilin-1 is a key mediator of cardiomyocyte-specific hypertrophic remodelling. Methods and results Profilin-1 was elevated in multiple mouse models of hypertrophy, and a cardiomyocyte-specific increase of profilin in Drosophila resulted in significantly larger heart tube dimensions. Moreover, adenovirus-mediated overexpression of profilin-1 in neonatal rat ventricular myocytes (NRVMs) induced a hypertrophic response, measured by increased myocyte size and gene expression. Profilin-1 silencing suppressed the response in NRVMs stimulated with phenylephrine or endothelin-1. Mechanistically, we found that profilin-1 regulates hypertrophy, in part, through activation of the ERK1/2 signalling cascade. Confocal microscopy showed that profilin localized to the Z-line of Drosophila myofibrils under normal conditions and accumulated near the M-line when overexpressed. Elevated profilin levels resulted in elongated sarcomeres, myofibrillar disorganization, and sarcomeric disarray, which correlated with impaired muscle function. Conclusion Our results identify novel roles for profilin as an important mediator of cardiomyocyte hypertrophy. We show that overexpression of profilin is sufficient to induce cardiomyocyte hypertrophy and sarcomeric remodelling, and silencing of profilin attenuates the hypertrophic response. PMID:26956799

  17. Mechanisms for altered carnitine content in hypertrophied rat hearts

    SciTech Connect

    Reibel, D.K.; O'Rourke, B.; Foster, K.A.

    1987-03-01

    Carnitine levels are reduced in hypertrophied hearts of rats subjected to aortic constriction (banding) and evaluated in hypertrophied hearts of spontaneously hypertensive rats (SHR). In an attempt to determine the mechanisms for these alterations, L-(/sup 14/C)carnitine transport was examined in isolated perfused hearts. Total carnitine uptake was significantly reduced by approx.20% in hypertrophied hearts of banded rats at all perfusate carnitine concentrations employed. The reduction in total uptake was due to a 40% reduction in carrier-mediated carnitine uptake with no difference in uptake by diffusion. In contrast, carnitine uptake was not altered in isolated hypertrophied hearts of SHR. However, serum carnitine levels were elevated in SHR, which could result in increased myocardial carnitine uptake in vivo. The data suggest that altered carnitine content in hypertrophied hearts of aortic-banded rats is due to an alteration in the carrier-mediated carnitine transport system in the myocardium. However, altered carnitine content in hypertrophied hearts of SHR is not due to a change in the carnitine transport system per se but may rather be due to a change in serum carnitine levels.

  18. Establishment and characterisation of a novel bovine SV40 large T-antigen-transduced foetal hepatocyte-derived cell line.

    PubMed

    Gleich, Alexander; Kaiser, Bastian; Schumann, Julia; Fuhrmann, Herbert

    2016-06-01

    Due to lack of in vitro models for bovine hepatocytes apart from primary cells, there is demand for a bovine hepatocyte-derived cell line. Transduction of bovine foetal hepatocytes with SV40 large T-antigen was performed using the vector pRetro-E2 SV40. Phase contrast microscopy was carried out to evaluate morphology. Immunofluorescence staining was conducted to study expression of keratins, tight junction proteins zona occludens-1 and claudin-1, glucose transporter-2 and P-glycoprotein as well as phosphoenolpyruvate carboxykinase. Urea and triglyceride production was quantified photometrically. Histochemical staining of glycogen by Periodic acid-Schiff stain and of lipids with Oil red O was performed after 24 h incubation with 20 mM glucose and 85 μM palmitic acid, respectively. Gene expression analysis of hepatocyte-typical genes was conducted by reverse transcription PCR. We obtained a SV40LTAg-transduced extended passage cell line, referred to as BFH12. Polygonal growth, keratins, tight junction proteins zona occludens-1 and claudin-1 and glucose transporter-2 as well as P-glycoprotein and phosphoenolpyruvate carboxykinase were attested positively. Urea production calculated as cell-specific rate was 14.2 ± 2.0 fmol/h (early passage) and 17.6 ± 3.7 fmol/h (late passage). Cell-specific triglyceride production was 1.6 ± 0.5 fmol/h (early passage) and 2.1 ± 0.3 fmol/h (late passage). Additionally, cells were positive for glycogen and lipid storage and showed a gene expression pattern resembling foetal hepatocytes. With the properties described here, the novel cell line BFH12 is a hepatocyte-derived cell line which can be used as an in vitro whole cell model.

  19. Structural and functional hepatocyte polarity and liver disease

    PubMed Central

    Gissen, Paul; Arias, Irwin M.

    2015-01-01

    Summary Hepatocytes form a crucially important cell layer that separates sinusoidal blood from the canalicular bile. They have a uniquely organized polarity with a basal membrane facing liver sinusoidal endothelial cells, while one or more apical poles can contribute to several bile canaliculi jointly with the directly opposing hepatocytes. Establishment and maintenance of hepatocyte polarity is essential for many functions of hepatocytes and requires carefully orchestrated cooperation between cell adhesion molecules, cell junctions, cytoskeleton, extracellular matrix and intracellular trafficking machinery. The process of hepatocyte polarization requires energy and, if abnormal, may result in severe liver disease. A number of inherited disorders affecting tight junction and intracellular trafficking proteins have been described and demonstrate clinical and pathophysiological features overlapping those of the genetic cholestatic liver diseases caused by defects in canalicular ABC transporters. Thus both structural and functional components contribute to the final hepatocyte polarity phenotype. Many acquired liver diseases target factors that determine hepatocyte polarity, such as junctional proteins. Hepatocyte depolarization frequently occurs but is rarely recognized because hematoxylin-eosin staining does not identify the bile canaliculus. However, the molecular mechanisms underlying these defects are not well understood. Here we aim to provide an update on the key factors determining hepatocyte polarity and how it is affected in inherited and acquired diseases. PMID:26116792

  20. Hepatocyte transplantation program: Lessons learned and future strategies

    PubMed Central

    Ibars, Eugenia Pareja; Cortes, Miriam; Tolosa, Laia; Gómez-Lechón, Maria José; López, Slivia; Castell, José Vicente; Mir, José

    2016-01-01

    This review aims to share the lessons we learned over time during the setting of the hepatocyte transplantation (HT) program at the Hepatic Cell Therapy Unit at Hospital La Fe in Valencia. New sources of liver tissue for hepatocyte isolation have been explored. The hepatocyte isolation and cryopreservation procedures have been optimized and quality criteria for assessment of functionality of hepatocyte preparations and suitability for HT have been established. The results indicate that: (1) Only highly viable and functional hepatocytes allow to recover those functions lacking in the native liver; (2) Organs with steatosis (≥ 40%) and from elderly donors are declined since low hepatocyte yields, viability and cell survival after cryopreservation, are obtained; (3) Neonatal hepatocytes are cryopreserved without significant loss of viability or function representing high-quality cells to improve human HT; (4) Cryopreservation has the advantage of providing hepatocytes constantly available and of allowing the quality evaluation and suitability for transplantation; and (5) Our results from 5 adults with acute liver failure and 4 from children with inborn metabolic diseases, indicate that HT could be a very useful and safe cell therapy, as long as viable and metabolically functional human hepatocytes are used. PMID:26811633

  1. Effect of. cap alpha. -ketobutyrate on the metabolism of pyruvate and palmitate in isolated rat hepatocytes

    SciTech Connect

    Brass, E.P.

    1986-05-01

    Alpha-ketobutyrate (..cap alpha..KB), an intermediate in the catabolism of threonine and methionine, is decarboxylated to propionyl-CoA. The authors have reported that propionate (PROP) inhibits oxidative metabolism in rate hepatocytes. Based on these observations, the present study examined the effects of ..cap alpha..KB on pyruvate and palmitate metabolism in hepatocytes isolated from fed rats. Similar to PROP, ..cap alpha..KB (10mM) inhibited palmitate oxidation and this inhibition was diminished when 10mM carnitine (CN) was added (35 +/- 6% inhibition without CN, 22 +/- 8% with CN). ..cap alpha..KB inhibited the conversion of 3-/sup 14/C-pyruvate to glucose and CO/sub 2/. Inhibition of pyruvate metabolism by ..cap alpha..KB was concentration-dependent. At equal concentrations, ..cap alpha..KB inhibited pyruvate metabolism to a greater extent than PROP. Addition of CN partially reversed the effects of PROP on pyruvate metabolism, but not those of ..cap alpha..KB despite the generation of propionylcarnitine when ..cap alpha..KB and CN were included in the incubation. These results demonstrate that accumulation of ..cap alpha..KB can impair normal hepatocyte metabolism. While some of the effects of ..cap alpha..KB can be explained on the basis of propionyl-CoA formation, ..cap alpha..KB has effects on pyruvate metabolism not explainable by this mechanism.

  2. Non-coding RNAs in cardiac hypertrophy.

    PubMed

    Ottaviani, Lara; da Costa Martins, Paula A

    2017-02-23

    Heart Failure is one of the largest contributors to disease burden and healthcare outflow in the Western world. Despite significant progress in the treatment of heart failure, disease prognosis remains very poor with the only curative therapy still being heart transplantation. To counteract the current situation, efforts have been made to better understand the underlying molecular pathways in the progression of cardiac disease towards heart failure, and to link the disease to novel therapeutic targets such as non-coding RNAs. The non-coding part of the genome has gained prominence over the last couple of decades by opening a completely new research field and having established different non-coding RNAs species as fundamental regulators of cellular functions. Not surprisingly, their dysregulation is increasingly being linked to pathology, including to cardiac disease. Pre-clinically, non-coding RNAs have been shown to be of great value as therapeutic targets in pathological cardiac remodelling and also as diagnostic/prognostic biomarkers for heart failure. Therefore, it is to expect that non-coding RNA-based therapeutic strategies will reach the bedside in the future and provide new and more efficient treatments for heart failure. Here, we review recent discoveries linking the function and molecular interactions of non-coding RNAs with the pathophysiology of cardiac hypertrophy and heart failure. This article is protected by copyright. All rights reserved.

  3. Intracellular cholesterol-binding proteins enhance HDL-mediated cholesterol uptake in cultured primary mouse hepatocytes

    PubMed Central

    Storey, Stephen M.; McIntosh, Avery L.; Huang, Huan; Landrock, Kerstin K.; Martin, Gregory G.; Landrock, Danilo; Payne, H. Ross; Atshaves, Barbara P.; Kier, Ann B.

    2012-01-01

    A major gap in our knowledge of rapid hepatic HDL cholesterol clearance is the role of key intracellular factors that influence this process. Although the reverse cholesterol transport pathway targets HDL to the liver for net elimination of free cholesterol from the body, molecular details governing cholesterol uptake into hepatocytes are not completely understood. Therefore, the effects of sterol carrier protein (SCP)-2 and liver fatty acid-binding protein (L-FABP), high-affinity cholesterol-binding proteins present in hepatocyte cytosol, on HDL-mediated free cholesterol uptake were examined using gene-targeted mouse models, cultured primary hepatocytes, and 22-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol). While SCP-2 overexpression enhanced NBD-cholesterol uptake, counterintuitively, SCP-2/SCP-x gene ablation also 1) enhanced the rapid molecular phase of free sterol uptake detectable in <1 min and initial rate and maximal uptake of HDL free cholesterol and 2) differentially enhanced free cholesterol uptake mediated by the HDL3, rather than the HDL2, subfraction. The increased HDL free cholesterol uptake was not due to increased expression or distribution of the HDL receptor [scavenger receptor B1 (SRB1)], proteins regulating SRB1 [postsynaptic density protein (PSD-95)/Drosophila disk large tumor suppressor (dlg)/tight junction protein (ZO1) and 17-kDa membrane-associated protein], or other intracellular cholesterol trafficking proteins (steroidogenic acute response protein D, Niemann Pick C, and oxysterol-binding protein-related proteins). However, expression of L-FABP, the single most prevalent hepatic cytosolic protein that binds cholesterol, was upregulated twofold in SCP-2/SCP-x null hepatocytes. Double-immunogold electron microscopy detected L-FABP sufficiently close to SRB1 for direct interaction, similar to SCP-2. These data suggest a role for L-FABP in HDL cholesterol uptake, a finding confirmed with SCP-2

  4. Intracellular cholesterol-binding proteins enhance HDL-mediated cholesterol uptake in cultured primary mouse hepatocytes.

    PubMed

    Storey, Stephen M; McIntosh, Avery L; Huang, Huan; Landrock, Kerstin K; Martin, Gregory G; Landrock, Danilo; Payne, H Ross; Atshaves, Barbara P; Kier, Ann B; Schroeder, Friedhelm

    2012-04-15

    A major gap in our knowledge of rapid hepatic HDL cholesterol clearance is the role of key intracellular factors that influence this process. Although the reverse cholesterol transport pathway targets HDL to the liver for net elimination of free cholesterol from the body, molecular details governing cholesterol uptake into hepatocytes are not completely understood. Therefore, the effects of sterol carrier protein (SCP)-2 and liver fatty acid-binding protein (L-FABP), high-affinity cholesterol-binding proteins present in hepatocyte cytosol, on HDL-mediated free cholesterol uptake were examined using gene-targeted mouse models, cultured primary hepatocytes, and 22-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-23,24-bisnor-5-cholen-3β-ol (NBD-cholesterol). While SCP-2 overexpression enhanced NBD-cholesterol uptake, counterintuitively, SCP-2/SCP-x gene ablation also 1) enhanced the rapid molecular phase of free sterol uptake detectable in <1 min and initial rate and maximal uptake of HDL free cholesterol and 2) differentially enhanced free cholesterol uptake mediated by the HDL3, rather than the HDL2, subfraction. The increased HDL free cholesterol uptake was not due to increased expression or distribution of the HDL receptor [scavenger receptor B1 (SRB1)], proteins regulating SRB1 [postsynaptic density protein (PSD-95)/Drosophila disk large tumor suppressor (dlg)/tight junction protein (ZO1) and 17-kDa membrane-associated protein], or other intracellular cholesterol trafficking proteins (steroidogenic acute response protein D, Niemann Pick C, and oxysterol-binding protein-related proteins). However, expression of L-FABP, the single most prevalent hepatic cytosolic protein that binds cholesterol, was upregulated twofold in SCP-2/SCP-x null hepatocytes. Double-immunogold electron microscopy detected L-FABP sufficiently close to SRB1 for direct interaction, similar to SCP-2. These data suggest a role for L-FABP in HDL cholesterol uptake, a finding confirmed with SCP-2

  5. High concentrations of stavudine impair fatty acid oxidation without depleting mitochondrial DNA in cultured rat hepatocytes.

    PubMed

    Igoudjil, Anissa; Massart, Julie; Begriche, Karima; Descatoire, Véronique; Robin, Marie-Anne; Fromenty, Bernard

    2008-06-01

    The antiretroviral nucleoside reverse-transcriptase inhibitor (NRTI) stavudine (d4T) can induce mild to severe liver injuries such as steatosis (i.e. triglyceride accumulation), steatohepatitis and liver failure. NRTI-induced toxicity has been ascribed to the inhibition of mitochondrial DNA (mtDNA) replication causing mtDNA depletion and respiratory chain dysfunction. This can secondarily impair the tricarboxylic acid cycle and fatty acid oxidation (FAO), thus leading to lactic acidosis and hepatic steatosis. However, NRTIs could also impair mitochondrial function and induce hepatic steatosis through other mechanisms. In this study, we sought to determine whether d4T could inhibit mitochondrial FAO and induce triglyceride accumulation through a mtDNA-independent mechanism. Since human tumoral and non-tumoral hepatic cell lines were unable to efficiently oxidize palmitic acid, the effects of d4T on mitochondrial FAO were assessed on cultured rat hepatocytes. Our results showed that 750 microM of d4T significantly inhibited palmitic acid oxidation after 48 or 72 h of culture, without inducing cell death. Importantly, high concentrations of zidovudine and zalcitabine (two other NRTIs that can induce hepatic steatosis), or beta-aminoisobutyric acid (a d4T metabolite), did not impair FAO in rat hepatocytes. D4T-induced FAO inhibition was observed without mtDNA depletion and lactate production, and was fully prevented with l-carnitine or clofibrate coincubation. l-carnitine also prevented the accretion of neutral lipids within rat hepatocytes. High concentrations of d4T were unable to inhibit FAO on freshly isolated liver mitochondria. Moreover, a microarray analysis was performed to clarify the mechanism whereby d4T can inhibit mitochondrial FAO and induce triglyceride accumulation in rat hepatocytes. The microarray data, confirmed by quantitative real-time PCR analysis, showed that d4T increased the expression of sterol regulatory element-binding protein-1c (SREBP1c

  6. Reversible Sterilization

    ERIC Educational Resources Information Center

    Largey, Gale

    1977-01-01

    Notes that difficult questions arise concerning the use of sterilization for alleged eugenic and euthenic purposes. Thus, how reversible sterilization will be used with relation to the poor, mentally ill, mentally retarded, criminals, and minors, is questioned. (Author/AM)

  7. Reversible Cardiomyopathies

    PubMed Central

    Patel, Harsh; Madanieh, Raef; Kosmas, Constantine E; Vatti, Satya K; Vittorio, Timothy J

    2015-01-01

    Cardiomyopathies (CMs) have many etiological factors that can result in severe structural and functional dysregulation. Fortunately, there are several potentially reversible CMs that are known to improve when the root etiological factor is addressed. In this article, we discuss several of these reversible CMs, including tachycardia-induced, peripartum, inflammatory, hyperthyroidism, Takotsubo, and chronic illness–induced CMs. Our discussion also includes a review on their respective pathophysiology, as well as possible management solutions. PMID:26052233

  8. PPARdelta activation normalizes cardiac substrate metabolism and reduces right ventricular hypertrophy in congestive heart failure.

    PubMed

    Jucker, Beat M; Doe, Christopher P; Schnackenberg, Christine G; Olzinski, Alan R; Maniscalco, Kristeen; Williams, Carolyn; Hu, Tom C-C; Lenhard, Stephen C; Costell, Melissa; Bernard, Roberta; Sarov-Blat, Lea; Steplewski, Klaudia; Willette, Robert N

    2007-07-01

    Previously, it was shown that selective deletion of peroxisome proliferator activated receptor delta (PPARdelta) in the heart resulted in a cardiac lipotoxicity, hypertrophy, and heart failure. The aim of the present study was to determine the effects of chronic and selective pharmacological activation of PPARdelta in a model of congestive heart failure. PPARdelta-specific agonist treatment (GW610742X at 30 and 100 mg/kg/day for 6-9 weeks) was initiated immediately postmyocardial infarction (MI) in Sprague-Dawley rats. Magnetic resonance imaging/spectroscopy was used to assess cardiac function and energetics. A 1-(13)C glucose clamp was performed to assess relative cardiac carbohydrate versus fat oxidation. Additionally, cardiac hemodynamics and reverse-transcription polymerase chain reaction gene expression analysis was performed. MI rats had significantly reduced left ventricle (LV) ejection fractions and whole heart phosphocreatine/adenosine triphosphate ratio compared with Sham animals (reduction of 43% and 14%, respectively). However, GW610742X treatment had no effect on either parameter. In contrast, the decrease in relative fat oxidation rate observed in both LV and right ventricle (RV) following MI (decrease of 58% and 54%, respectively) was normalized in a dose-dependent manner following treatment with GW610742X. These metabolic changes were associated with an increase in lipid transport/metabolism target gene expression (eg, CD36, CPT1, UCP3). Although there was no difference between groups in LV weight or infarct size measured upon necropsy, there was a dramatic reduction in RV hypertrophy and lung congestion (decrease of 22-48%, P<0.01) with treatment which was associated with a >7-fold decrease (P<0.05) in aterial natriuretic peptide gene expression in RV. Diuretic effects were not observed with GW610742X. In conclusion, chronic treatment with a selective PPARdelta agonist normalizes cardiac substrate metabolism and reduces RV hypertrophy and pulmonary

  9. The relation between childhood obesity and adenotonsillar hypertrophy.

    PubMed

    Daar, Ghaniya; Sarı, Kamran; Gencer, Zeliha Kapusuz; Ede, Hüseyin; Aydın, Reha; Saydam, Levent

    2016-02-01

    Childhood obesity is a common and significant public health problem all over the world. As a well-known fact obese children have an increased risk of obesity-associated comorbidities, including obstructive sleep apnea, diabetes, and cardiovascular disorders at an earlier age compared to their normal weight peers. They also have an increased risk of poor self-esteem, greater body dissatisfaction, and increased peer teasing that lead to a lower health-related quality of life. While the presence of adenoid hypertrophy and increased rate of obstructive sleep apnea frequently co-exists in majority of cases. We have limited knowledge about the effect of adenotonsillar hypertrophy on development of childhood obesity. In this study, we aimed to investigate the association between obesity, presence of adenotonsillar hypertrophy and the quality of life parameters in obese children as measured by the OSA-18 quality of life questionnaire. Fifty obese children aged between 3 and 18 years and 50 age- and gender-matched otherwise children were enrolled to the study. All subjects were routinely examined by the otolaryngologist before enrollment. The size of adenoid hypertrophy was measured using lateral cephalometric radiographs. The tonsils were also graded using the schema recommended by Brodsky et al. We used OSA-18 questionnaires to evaluate the subjects' quality of life issues. We found, 34 % of obese group had tonsillar hypertrophy while the rate was 6 % in control group. Similarly 16 % of obese group had tonsillar hypertrophy compared to only 4 % in non-obese group. It was also noted that total OSA-18 scores of obese group were significantly higher than those of non-obese group. In subgroup analysis of obese group, total OSA-18 score of obese subjects with either adenoid and/or tonsillar hypertrophy was significantly higher than that of obese subjects without adenoid or tonsillar hypertrophy. As the related literature suggests that the impact of adenotonsillar size on OSA

  10. Roles of hepatocyte nuclear factors in hepatitis B virus infection

    PubMed Central

    Kim, Doo Hyun; Kang, Hong Seok; Kim, Kyun-Hwan

    2016-01-01

    Approximately 350 million people are estimated to be persistently infected with hepatitis B virus (HBV) worldwide. HBV maintains persistent infection by employing covalently closed circular DNA (cccDNA), a template for all HBV RNAs. Chronic hepatitis B (CHB) patients are currently treated with nucleos(t)ide analogs such as lamivudine, adefovir, entecavir, and tenofovir. However, these treatments rarely cure CHB because they are unable to inhibit cccDNA transcription and inhibit only a late stage in the HBV life cycle (the reverse transcription step in the nucleocapsid). Therefore, an understanding of the factors regulating cccDNA transcription is required to stop this process. Among numerous factors, hepatocyte nuclear factors (HNFs) play the most important roles in cccDNA transcription, especially in the generation of viral genomic RNA, a template for HBV replication. Therefore, proper control of HNF function could lead to the inhibition of HBV replication. In this review, we summarize and discuss the current understanding of the roles of HNFs in the HBV life cycle and the upstream factors that regulate HNFs. This knowledge will enable the identification of new therapeutic targets to cure CHB. PMID:27610013

  11. [Encapsulating hepatocytes with chitosan in physiological conditions].

    PubMed

    Zhu, Jianhang; Zhang, Bao; Yan, Xiluan; Lao, Xuejun; Yu, Hanry

    2006-10-01

    Prepared from 15.3% N-acetylated chitosan (FNC), half N-acetylated chitosan (HNC) possesses a good solubility in a weak basic solution, guaranteeing the formation of microcapsules by the coacervating reaction between HNC and methacrylic acid (MAA)-hydroxyethyl methacrylate (HEMA)-methyl methacrylate (MMA) (MAA-HEMA-MMA) terpolymer under physiological conditions. When hepatocytes were encapsulated in such 3-dimensional microenvironment, as compared to monolayer culture, cell functions, including P450 activity, urea production and albumin release, were well supported. The prepared microcapsules have good mechanical stability and permeability.

  12. The transcription factor GATA-6 regulates pathological cardiac hypertrophy

    PubMed Central

    van Berlo, Jop H.; Elrod, John W.; van den Hoogenhof, Maarten M.G.; York, Allen J.; Aronow, Bruce J.; Duncan, Stephen A.; Molkentin, Jeffery D.

    2010-01-01

    Rationale The transcriptional code that programs maladaptive cardiac hypertrophy involves the zinc finger-containing DNA binding factor GATA-4. The highly related transcription factor GATA-6 is also expressed in the adult heart, although its role in controlling the hypertrophic program is unknown. Objective To determine the role of GATA-6 in cardiac hypertrophy and homeostasis. Methods and Results Here we performed a cardiomyocyte-specific conditional gene targeting approach for Gata6, as well as a transgenic approach to overexpress GATA-6 in the mouse heart. Deletion of Gata6-loxP with Nkx2.5-cre produced late embryonic lethality with heart defects, while deletion with β-myosin heavy chain-cre (βMHC-cre) produced viable adults with greater than 95% loss of GATA-6 protein in the heart. These later mice were subjected to pressure overload induced hypertrophy for 2 and 6 weeks, which showed a significant reduction in cardiac hypertrophy similar to that observed Gata4 heart-specific deleted mice. Gata6-deleted mice subjected to pressure overload also developed heart failure while control mice maintained proper cardiac function. Gata6-deleted mice also developed less cardiac hypertrophy following 2 weeks of angiotensin II/phenylephrine infusion. Controlled GATA-6 overexpression in the heart induced hypertrophy with aging and predisposed to greater hypertrophy with pressure overload stimulation. Combinatorial deletion of Gata4 and Gata6 from the adult heart resulted in dilated cardiomyopathy and lethality by 16 weeks of age. Mechanistically, deletion of Gata6 from the heart resulted in fundamental changes in the levels of key regulatory genes and myocyte differentiation-specific genes. Conclusions These results indicate that GATA-6 is both necessary and sufficient for regulating the cardiac hypertrophic response and differentiated gene expression, both alone and in coordination with GATA-4. PMID:20705924

  13. Cytoskeletal mechanics in pressure-overload cardiac hypertrophy

    NASA Technical Reports Server (NTRS)

    Tagawa, H.; Wang, N.; Narishige, T.; Ingber, D. E.; Zile, M. R.; Cooper, G. 4th

    1997-01-01

    We have shown that the cellular contractile dysfunction characteristic of pressure-overload cardiac hypertrophy results not from an abnormality intrinsic to the myofilament portion of the cardiocyte cytoskeleton but rather from an increased density of the microtubule component of the extramyofilament portion of the cardiocyte cytoskeleton. To determine how, in physical terms, this increased microtubule density mechanically overloads the contractile apparatus at the cellular level, we measured cytoskeletal stiffness and apparent viscosity in isolated cardiocytes via magnetic twisting cytometry, a technique by which magnetically induced force is applied directly to the cytoskeleton through integrin-coupled ferromagnetic beads coated with Arg-Gly-Asp (RGD) peptide. Measurements were made in two groups of cardiocytes from cats with right ventricular (RV) hypertrophy induced by pulmonary artery banding: (1) those from the pressure-overloaded RV and (2) those from the normally loaded same-animal control left ventricle (LV). Cytoskeletal stiffness increased almost twofold, from 8.53 +/- 0.77 dyne/cm2 in the normally loaded LV cardiocytes to 16.46 +/- 1.32 dyne/cm2 in the hypertrophied RV cardiocytes. Cytoskeletal apparent viscosity increased almost fourfold, from 20.97 +/- 1.92 poise in the normally loaded LV cardiocytes to 87.85 +/- 6.95 poise in the hypertrophied RV cardiocytes. In addition to these baseline data showing differing stiffness and, especially, apparent viscosity in the two groups of cardiocytes, microtubule depolymerization by colchicine was found to return both the stiffness and the apparent viscosity of the pressure overload-hypertrophied RV cells fully to normal. Conversely, microtubule hyperpolymerization by taxol increased the stiffness and apparent viscosity values of normally loaded LV cardiocytes to the abnormal values given above for pressure-hypertrophied RV cardiocytes. Thus, increased microtubule density constitutes primarily a viscous load on

  14. The effect of exercise training on transverse tubules in normal, remodeled, and reverse remodeled hearts.

    PubMed

    Kemi, Ole J; Hoydal, Morten A; Macquaide, Niall; Haram, Per M; Koch, Lauren G; Britton, Steven L; Ellingsen, Oyvind; Smith, Godfrey L; Wisloff, Ulrik

    2011-09-01

    The response of transverse (T)-tubules to exercise training in health and disease remains unclear. Therefore, we studied the effect of exercise training on the density and spacing of left ventricle cardiomyocyte T-tubules in normal and remodeled hearts that associate with detubulation, by confocal laser scanning microscopy. First, exercise training in normal rats increased cardiomyocyte volume by 16% (P < 0.01), with preserved T-tubule density. Thus, the T-tubules adapted to the physiologic hypertrophy. Next, we studied T-tubules in a rat model of metabolic syndrome with pressure overload-induced concentric left ventricle hypertrophy, evidenced by 15% (P < 0.01) increased cardiomyocyte size. These rats had only 85% (P < 0.01) of the T-tubule density of control rats. Exercise training further increased cardiomyocyte volume by 8% (P < 0.01); half to that in control rats, but the T-tubule density remained unchanged. Finally, post-myocardial infarction heart failure induced severe cardiac pathology, with a 70% (P < 0.01) increased cardiomyocyte volume that included both eccentric and concentric hypertrophy and 55% (P < 0.01) reduced T-tubule density. Exercise training reversed 50% (P < 0.01) of the pathologic hypertrophy, whereas the T-tubule density increased by 40% (P < 0.05) compared to sedentary heart failure, but remained at 60% of normal hearts (P < 0.01). Physiologic hypertrophy associated with conserved T-tubule spacing (~1.8-1.9 µm), whereas in pathologic hypertrophy, T-tubules appeared disorganized without regular spacing. In conclusion, cardiomyocytes maintain the relative T-tubule density during physiologic hypertrophy and after mild concentric pathologic hypertrophy, whereas after severe pathologic remodeling with a substantial loss of T-tubules; exercise training reverses the remodeling and partly corrects the T-tubule density.

  15. Endothelial Nogo-B regulates sphingolipid biosynthesis to promote pathological cardiac hypertrophy during chronic pressure overload

    PubMed Central

    Huang, Yan; Azevedo, Paula S.; Siragusa, Mauro; Bielawski, Jacek; Giordano, Frank J.

    2016-01-01

    We recently discovered that endothelial Nogo-B, a membrane protein of the ER, regulates vascular function by inhibiting the rate-limiting enzyme, serine palmitoyltransferase (SPT), in de novo sphingolipid biosynthesis. Here, we show that endothelium-derived sphingolipids, particularly sphingosine-1-phosphate (S1P), protect the heart from inflammation, fibrosis, and dysfunction following pressure overload and that Nogo-B regulates this paracrine process. SPT activity is upregulated in banded hearts in vivo as well as in TNF-α–activated endothelium in vitro, and loss of Nogo removes the brake on SPT, increasing local S1P production. Hence, mice lacking Nogo-B, systemically or specifically in the endothelium, are resistant to the onset of pathological cardiac hypertrophy. Furthermore, pharmacological inhibition of SPT with myriocin restores permeability, inflammation, and heart dysfunction in Nogo-A/B–deficient mice to WT levels, whereas SEW2871, an S1P1 receptor agonist, prevents myocardial permeability, inflammation, and dysfunction in WT banded mice. Our study identifies a critical role of endothelial sphingolipid biosynthesis and its regulation by Nogo-B in the development of pathological cardiac hypertrophy and proposes a potential therapeutic target for the attenuation or reversal of this clinical condition. PMID:27158676

  16. Autophagy regulates hepatocyte identity and epithelial-to-mesenchymal and mesenchymal-to-epithelial transitions promoting Snail degradation.

    PubMed

    Grassi, G; Di Caprio, G; Santangelo, L; Fimia, G M; Cozzolino, A M; Komatsu, M; Ippolito, G; Tripodi, M; Alonzi, T

    2015-09-10

    Epithelial-to-mesenchymal transition (EMT) and the reverse process mesenchymal-to-epithelial transition (MET) are events involved in development, wound healing and stem cell behaviour and contribute pathologically to cancer progression. The identification of the molecular mechanisms underlying these phenotypic conversions in hepatocytes are fundamental to design specific therapeutic strategies aimed at optimising liver repair. The role of autophagy in EMT/MET processes of hepatocytes was investigated in liver-specific autophagy-deficient mice (Alb-Cre;ATG7(fl/fl)) and using the nontumorigenic immortalised hepatocytes cell line MMH. Autophagy deficiency in vivo reduces epithelial markers' expression and increases the levels of mesenchymal markers. These alterations are associated with an increased protein level of the EMT master regulator Snail, without transcriptional induction. Interestingly, we found that autophagy degrades Snail in a p62/SQSTM1 (Sequestosome-1)-dependent manner. Moreover, accordingly to a pro-epithelial function, we observed that autophagy stimulation strongly affects EMT progression, whereas it is necessary for MET. Finally, we found that the EMT induced by TGFβ affects the autophagy flux, indicating that these processes regulate each other. Overall, we found that autophagy regulates the phenotype plasticity of hepatocytes promoting their epithelial identity through the inhibition of the mesenchymal programme.

  17. Protective effects of hepatocyte-specific glycyrrhetic derivatives against carbon tetrachloride-induced liver damage in mice.

    PubMed

    Yang, Yifei; Yang, Lingyun; Han, Yaodan; Wu, Zhenwei; Chen, Pan; Zhang, Huibin; Zhou, Jinpei

    2017-03-20

    Glycyrrhetic acid (GA), the main hydrolysate of glycyrrhizic acid extracted from the roots of the Chinese herb Glycyrrhiza glabra, was reported to be accumulated in hepatocytes due to the extensive distribution of GA receptors in liver. A series of hepatocyte-specific derivatives on the basis of anetholtrithione and glycyrrhizic were designed and synthesized. The potential beneficial effect was evaluated in carbon tetrachloride (CCl4)-induced liver injury model. In addition, the hepatoprotective activity of these derivatives was assessed by measuring levels of serum marker enzymes, including serum glutamate oxaloacetate transaminase (GOT), serum glutamate pyruvate transaminase (GPT), alkaline phosphatase (AKP), lactate dehydrogenase (LDH) and the ratio of GSH to GSSG. Gratifyingly, compounds 5a-c (100mg/kg, p.o.) markedly prevented CCl4-induced elevation of levels of serum GPT, GOT. A comparative histopathological study of liver exhibited almost a normal liver lobular architecture and cell structure of the livers, as compared to CCl4-treated group. These findings were confirmed with the histopathological observations, where hepatocyte-specific glycyrrhetic acid derivatives 5a-c were capable of reversing the toxic effects of CCl4 on hepatocytes.

  18. Hepatocyte membrane water permeability measured by silicone layer filtering centrifugation.

    PubMed

    Gradilone, Sergio A; Ochoa, J Elena; García, Fabiana; Larocca, M Cecilia; Pellegrino, José M; Marinelli, Raúl A

    2002-03-01

    We previously found that hepatocytes are able to control their osmotic membrane water permeability (P(f)) by regulating the number of surface aquaporin water channels. Hepatocyte P(f) has been assessed by phase-contrast microscopy and cell image analysis, an established but relatively laborious procedure. We report here an alternative method to assess hepatocyte P(f) based on a single silicone layer filtering centrifugation system. Isolated rat hepatocytes were incubated in hypotonic or isotonic buffers containing (3)H(2)O as a tracer and, then, were filtered by rapid centrifugation through a silicone layer down to a lysis layer. Osmotically driven radioactivity (i.e., (3)H(2)O) within hepatocytes was calculated as the difference between the dpm in lysis media measured under hypotonic and isotonic conditions. The P(f) calculated from the initial slope of the radioactivity-versus-time curve was 18 microm/s at 4 degrees C. Hepatocytes treated with dibutyryl cyclic AMP, to increase P(f) through the plasma membrane insertion of aquaporins, showed an increased P(f) value of 37 microm/s. The aquaporin blocker dimethyl sulfoxide selectively prevented the agonist-induced hepatocyte P(f). These data are in good agreement with the corresponding values determined by quantitative phase-contrast microscopy; thus, the method developed allows the rapid and reliable measurement of hepatocyte P(f).

  19. Inhibitory effects of interferon-gamma on myocardial hypertrophy.

    PubMed

    Jin, Hongkui; Li, Wei; Yang, Renhui; Ogasawara, Annie; Lu, Hsienwie; Paoni, Nicholas F

    2005-09-21

    Prostaglandin F(2alpha) (PGF(2alpha)) plays an important role in pathologic cardiac growth. After testing several immune cytokines, we found that interferon-gamma (IFN-gamma) inhibited responsiveness of adult myocytes to PGF(2alpha). The present study was designed to test the hypothesis that IFN-gamma inhibits cardiac hypertrophy induced by PGF(2alpha). Incubation of cultured adult rat cardiac myocytes with PGF(2alpha) caused cell spreading, which was inhibited by IFN-gamma. The inhibitory effect was not affected by nitric oxide (NO) synthase inhibitors. In addition, administration of fluprostenol, a more selective agonist at the PGF(2alpha) receptor, induced cardiac hypertrophy in rats. Chronic treatment with IFN-gamma inhibited this myocardial growth, and the inhibitory effect of IFN-gamma was not accompanied by an increase in myocardial NO synthase gene expression. Further, abdominal aortic constriction resulted in a substantial increase in heart, ventricular and left ventricular weights to BW ratio that was significantly attenuated by treatment with IFN-gamma. The results demonstrate that IFN-gamma inhibits the in vitro and in vivo effects of PGF(2alpha) on cardiac hypertrophy, and that the mechanism of action is likely independent of NO production. IFN-gamma also attenuated cardiac hypertrophy induced by pressure overload, suggesting that PGF(2alpha) plays a role in the pathogeneses of this severe type of cardiac hypertrophy.

  20. Sodium Butyrate Controls Cardiac Hypertrophy in Experimental Models of Rats.

    PubMed

    Patel, Bhoomika M

    2017-04-07

    The aim of the present research was to study the effect of sodium butyrate (SB) on partial abdominal aorta constriction (PAAC)-induced cardiac hypertrophy and determine its mechanism of action. Healthy Wistar rats were exposed to PAAC for eight weeks. After eight weeks, we carried out hypertrophic and hemodynamic evaluation and measured oxidative stress parameters and mitochondrial DNA concentration. PAAC control animals exhibited cardiac hypertrophy, decreased hemodynamic functions and oxidative stress. Treatment with SB reduced hypertrophic indices, LV wall thickness, LV collagen levels, cardiomyocyte diameter, serum lipid levels and serum cardiac biomarkers. Treatment with SB also improved hemodynamic functions, prevented oxidative stress and increased mitochondrial DNA concentration. Improvement in hypertrophy due to HDAC inhibition was further confirmed by HDAC mRNA expression studies which revealed that SB decreases expression of prohypertrophic HDAC, i.e., HDAC2, without altering the expression of anti-hypertrophic HDAC5. Sodium butyrate produces beneficial effect on cardiac hypertrophy as is evident, specifically from reduction in hypertrophic parameters including collagen levels, improvement in mitochondrial DNA concentration and preservation of LV systolic and diastolic dysfunction. This beneficial effect of sodium butyrate is mediated through downregulation of class I HDACs, specifically HDAC2 without any effect on class II HDAC, i.e., HDAC5. Thus, selective class I HDAC inhibition is required for controlling cardiac hypertrophy. Newer HDAC inhibitors which are class I inhibitor and class II promoter can be designed to obtain a 'pan' or 'dual' natural HDAC 'regulators.'

  1. Insulin internalization in isolated rat hepatocytes

    SciTech Connect

    Galan, J.; Trankina, M.; Noel, R.; Ward, W. )

    1990-02-26

    This project was designed to determine whether neomycin, an aminoglycoside antibiotic, has a significant effect upon the pathways of ligand endocytosis in isolated rat hepatocytes. The pathways studied include receptor-mediated endocytosis and fluid-phase endocytosis. Neomycin causes a dose-dependent acceleration of {sup 125}I-insulin internalization. Since fluid-phase endocytosis can also be a significant factor in {sup 125}I-insulin internalization, lucifer yellow (LY), a marker for fluid-phase endocytosis, was incorporated into an assay similar to the {sup 125}I-insulin internalization procedure. In the presence of 5 mM neomycin, a significant increase in LY uptake was evident at 0.2 and 0.4 mg/ml of LY. At 0.8 mg/ml, a decrease in LY uptake was observed. The increased rate of {sup 125}I-insulin internalization in the presence of neomycin was intriguing. Since one action of neomycin is to inhibit phosphoinositidase C, it suggests that the phosphotidylinositol cycle may be involved in ligand internalization by hepatocytes. At low insulin concentrations, receptor-mediated uptake predominates. Fluid-phase uptake can become an important uptake route as insulin concentrations are increased. Since neomycin stimulates fluid-phase endocytosis, it must also be taken into account when measuring ligand internalization.

  2. Mechanisms of the statins cytotoxicity in freshly isolated rat hepatocytes.

    PubMed

    Abdoli, Narges; Heidari, Reza; Azarmi, Yadollah; Eghbal, Mohammad Ali

    2013-06-01

    Statins are potent drugs, used as lipid-lowering agents in cardiovascular diseases. Hepatotoxicity is one of the serious adverse effects of statins, and the exact mechanism of hepatotoxicity is not yet clear. In this study, the cytotoxic effects of the most commonly used statins, that is, atorvastatin, lovastatin, and simvastatin toward isolated rat hepatocytes, were evaluated. Markers, such as cell death, reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial membrane potential, and the amount of reduced and oxidized glutathione in the statin-treated hepatocytes, were investigated. It was found that the statins caused cytotoxicity toward rat hepatocytes dose dependently. An elevation in ROS formation, accompanied by a significant amount of lipid peroxidation and mitochondrial depolarization, was observed. Cellular glutathione reservoirs were decreased, and a significant amount of oxidized glutathione was formed. This study suggests that the adverse effect of statins toward hepatocytes is mediated through oxidative stress and the hepatocytes mitochondria play an important role in the statin-induced toxicity.

  3. Berberine attenuates oxidative stress and hepatocytes apoptosis via protecting mitochondria in blunt snout bream Megalobrama amblycephala fed high-fat diets.

    PubMed

    Lu, Kang-Le; Wang, Li-Na; Zhang, Ding-Dong; Liu, Wen-Bin; Xu, Wei-Na

    2017-02-01

    High-fat diets may have favorable effects on growth and cost, but high-fat diets often induce excessive fat deposition, resulting in liver damage. This study aimed to identify the hepatoprotective of a Chinese herb (berberine) for blunt snout bream (Megalobrama amblycephala). Fish were fed with a normal diet (LFD, 5 % fat), high-fat diet (HFD, 15 % fat) or berberine-supplemented diets (BSD, 15 % fat with berberine 50 or 100 mg/kg level) for 8 weeks. After the feeding, histology, oxidative status and mitochondrial function of liver were assessed. The results showed that HFD caused fat accumulation, oxidative stress and apoptosis in hepatocytes of fish. Hepatocytes in HFD group appeared to be hypertrophied, with larger liver cells diameter than these of LFD group. Berberine-supplemented diets could attenuate oxidative stress and hepatocytes apoptosis. HFD induced the decreasing mitochondrial complexes activities and bulk density and surface area density. Berberine improved function of mitochondrial respiratory chain via increasing the complex activities. Moreover, the histological results showed that berberine has the potential to repair mitochondrial ultrastructural damage and elevate the density in cells. In conclusion, our study demonstrated that berberine has attenuated liver damage induced by the high fat mainly via the protection for mitochondria.

  4. GABA-B receptor activation inhibits the in vitro migration of malignant hepatocytes.

    PubMed

    Lodewyks, Carly; Rodriguez, Jose; Yan, Jing; Lerner, Betty; Lipschitz, Jeremy; Nfon, Charles; Rempel, Julia Darlene; Uhanova, Julia; Minuk, Gerald Yosel

    2011-06-01

    There are conflicting data regarding whether activation of γ-aminobutyric acid-B (GABA-B) receptors results in inhibition of tumor growth and invasion. The objectives of this study were to document the effects of the GABA-B receptor agonist baclofen on malignant hepatocyte proliferation and migration. We also sought to determine whether any effects on cell migration were mediated by changes in cyclic adenosine monophosphate (cAMP) signaling or matrix metalloproteinase (MMP) expression. Finally, GABA-B(1) and -B(2) receptor expression was documented in 2 malignant hepatocyte cell lines (PLC/PRF/5 and Huh-7) and 12 sets of human hepatocellular carcinoma and adjacent nontumor tissues. Cell proliferative activity was documented by WST-1 absorbance, migration by wound healing assays, cAMP levels by enzyme-linked immunoassay (ELISA), MMP by immunohistochemistry and ELISA, and GABA-B receptor expression by flow cytometry and reverse transcriptase - polymerase chain reaction. Although baclofen had no effect on cell proliferation, wound healing was delayed, an effect that was reversed by the GABA-B receptor antagonist CGP. cAMP levels were decreased in Huh-7 but not PLC cells exposed to baclofen. MMP expression remained unaltered in both cell lines. Finally, GABA-B(1) receptor expression was present and consistently expressed, but GABA-B(2) expression was limited and varied with the number of cell passages and (or) duration of culture. In conclusion, activation of GABA-B receptors has no effect on malignant hepatocyte proliferation but does decrease cell migration. This inhibitory effect may involve cAMP signaling but not MMP expression. GABA-B(2) receptor expression is limited and variable, which may help to explain discrepancies with previously published results.

  5. [Experimental atrophy/hypertrophy complex of the liver after portal and/or biliary ligation in the rat].

    PubMed

    Schweizer, W; Duda, P; Tanner, S; Balsiger, D; Höflin, F; Zimmermann, A; Blumgart, L H

    1992-08-01

    Patients with lobar or segmental, benign or malignant strictures of the biliary tree (with or without impairment of the portal blood flow) show a considerable atrophy of the involved area of the liver with a compensatory hypertrophy/hyperplasia of the remaining non affected liver. To investigate the importance of the biliary and portal obstruction for the development of this process, we used a rat model, with selective biliary and/or portal ligation of the anterior liver lobes (two thirds of the liver mass). Weight measurements, morphometry, functional scintigraphy (Hepatoiodida-scan) and blood enzyme analyses were done immediately postoperatively, at 30 hours and 4, 8 and 28 days after the operation. The major findings were: 1. 28 days after biliary and/or portal ligation there was no difference between the body weight of the four groups, all ligated animals having compensated for an initial greater percentage body-weight loss. 2. Total liver weight remained constant, while atrophy and hypertrophy/hyperplasia occurred although a progressive derangement of liver morphology was observed during that time. 3. A severe atrophy-hypertrophy-complex (AHC) developed after selective portal ligation, which in our experiment did not appear after selective biliary ligation. 4. Morphometrical changes after selective biliary ligation were reversible, whereas in liver lobes with selective portal ligation a progressive parenchymal destruction and involution with subsequent impairment of hepatic function of the concerned lobe was observed.

  6. A Single Injection of Hypertrophied Androgenic Gland Cells Produces All-Female Aquaculture.

    PubMed

    Levy, Tom; Rosen, Ohad; Eilam, Brit; Azulay, Dudu; Aflalo, Eliahu D; Manor, Rivka; Shechter, Assaf; Sagi, Amir

    2016-10-01

    Monosex culture, common in animal husbandry, enables gender-specific management. Here, production of all-female prawns (Macrobrachium rosenbergii) was achieved by a novel biotechnology comprising three steps: (a) A single injection of suspended hypertrophied androgenic gland cells caused fully functional sex reversal of females into "neo-males" bearing the WZ genotype; (b) crossing neo-males with normal females (WZ) yielded genomically validated WW females; and (c) WW females crossed with normal males (ZZ) yielded all-female progeny. This is the first sustainable biotechnology for large-scale all-female crustacean aquaculture. The approach is particularly suited to species in which females are superior to males and offers seedstock protection, thereby ensuring a quality seed supply. Our technology will thus revolutionize not only the structure of the crustacean aquaculture industry but can also be applied to other sectors. Finally, the production of viable and reproducible females lacking the Z chromosome questions its role, with respect to sexuality.

  7. Inhibition of Hepatocyte Apoptosis: An Important Mechanism of Corn Peptides Attenuating Liver Injury Induced by Ethanol.

    PubMed

    Ma, Zhili; Hou, Tao; Shi, Wen; Liu, Weiwei; He, Hui

    2015-09-11

    In this study, the effects of mixed corn peptides and synthetic pentapeptide (QLLPF) on hepatocyte apoptosis induced by ethanol were investigated in vivo. QLLPF, was previously characterized from corn protein hydrolysis, which had been shown to exert good facilitating alcohol metabolism activity. Mice were pre-treated with the mixed corn peptides and the pentapeptide for 1 week and then treated with ethanol. After treatment of three weeks, the biochemical indices and the key ethanol metabolizing enzymes, the serum TNF-α, liver TGF-β1 concentrations and the protein expressions related to apoptosis were determined. We found that the Bcl-2, Bax and cytochrome c expressions in the intrinsic pathway and the Fas, FasL and NF-κB expressions in the extrinsic pathway together with higher TNF-α and TGF-β1 concentrations were reversed compared with the model group by both the mixed corn peptides and the pentapeptide. The activation of caspase3 was also suppressed. Additionally, apoptosis was further confirmed with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and the TUNEL assay demonstrated peptides suppressed hepatocyte apoptosis. Our results suggest that apoptosis induced by ethanol is alleviated in response to the treatment of corn peptides, potentially due to reversing the related protein expression.

  8. Reversible Computing

    DTIC Science & Technology

    1980-02-01

    will have been introduced. 9. Reversible celular autemata We shall assume the reader to have some familiarity with the concept of cel- lular...10003 Mr. Kin B. Thcmpson 1 copy Technical Director Information Systems Divisia.i Naval Research Laboratory (OP-91T) Technical Information Division

  9. REVERSE OSMOSIS,

    DTIC Science & Technology

    acetate membranes. Mechanisms of the process and porous cellulose acetate membrane technology are briefly reviewed. Based on a general capillary...The reverse osmosis process is discussed with particular reference to systems involving aqueous solutions and Loeb-Sourirajan-type porous cellulose

  10. Strategies to minimize hypertrophy in cartilage engineering and regeneration

    PubMed Central

    Chen, Song; Fu, Peiliang; Cong, Ruijun; Wu, HaiShan; Pei, Ming

    2015-01-01

    Due to a blood supply shortage, articular cartilage has a limited capacity for self-healing once damaged. Articular chondrocytes, cartilage progenitor cells, embryonic stem cells, and mesenchymal stem cells are candidate cells for cartilage regeneration. Significant current attention is paid to improving chondrogenic differentiation capacity; unfortunately, the potential chondrogenic hypertrophy of differentiated cells is largely overlooked. Consequently, the engineered tissue is actually a transient cartilage rather than a permanent one. The development of hypertrophic cartilage ends with the onset of endochondral bone formation which has inferior mechanical properties. In this review, current strategies for inhibition of chondrogenic hypertrophy are comprehensively summarized; the impact of cell source options is discussed; and potential mechanisms underlying these strategies are also categorized. This paper aims to provide guidelines for the prevention of hypertrophy in the regeneration of cartilage tissue. This knowledge may also facilitate the retardation of osteophytes in the treatment of osteoarthritis. PMID:26000333

  11. Zinc Levels in Left Ventricular Hypertrophy.

    PubMed

    Huang, Lei; Teng, Tianming; Bian, Bo; Yao, Wei; Yu, Xuefang; Wang, Zhuoqun; Xu, Zhelong; Sun, Yuemin

    2017-03-01

    Zinc is one of the most important trace elements in the body and zinc homeostasis plays a critical role in maintaining cellular structure and function. Zinc dyshomeostasis can lead to many diseases, such as cardiovascular disease. Our aim was to investigate whether there is a relationship between zinc and left ventricular hypertrophy (LVH). A total of 519 patients was enrolled and their serum zinc levels were measured in this study. We performed analyses on the relationship between zinc levels and LVH and the four LV geometry pattern patients: normal LV geometry, concentric remodeling, eccentric LVH, and concentric LVH. We performed further linear and multiple regression analyses to confirm the relationship between zinc and left ventricular mass (LVM), left ventricular mass index (LVMI), and relative wall thickness (RWT). Our data showed that zinc levels were 710.2 ± 243.0 μg/L in the control group and were 641.9 ± 215.2 μg/L in LVH patients. We observed that zinc levels were 715 ± 243.5 μg/L, 694.2 ± 242.7 μg/L, 643.7 ± 225.0 μg/L, and 638.7 ± 197.0 μg/L in normal LV geometry, concentric remodeling, eccentric LVH, and concentric LVH patients, respectively. We further found that there was a significant inverse linear relationship between zinc and LVM (p = 0.001) and LVMI (p = 0.000) but did not show a significant relationship with RWT (p = 0.561). Multiple regression analyses confirmed that the linear relationship between zinc and LVM and LVMI remained inversely significant. The present study revealed that serum zinc levels were significantly decreased in the LVH patients, especially in the eccentric LVH and concentric LVH patients. Furthermore, zinc levels were significantly inversely correlated with LVM and LVMI.

  12. Extracellular high-mobility group box 1 mediates pressure overload-induced cardiac hypertrophy and heart failure.

    PubMed

    Zhang, Lei; Liu, Ming; Jiang, Hong; Yu, Ying; Yu, Peng; Tong, Rui; Wu, Jian; Zhang, Shuning; Yao, Kang; Zou, Yunzeng; Ge, Junbo

    2016-03-01

    Inflammation plays a key role in pressure overload-induced cardiac hypertrophy and heart failure, but the mechanisms have not been fully elucidated. High-mobility group box 1 (HMGB1), which is increased in myocardium under pressure overload, may be involved in pressure overload-induced cardiac injury. The objectives of this study are to determine the role of HMGB1 in cardiac hypertrophy and cardiac dysfunction under pressure overload. Pressure overload was imposed on the heart of male wild-type mice by transverse aortic constriction (TAC), while recombinant HMGB1, HMGB1 box A (a competitive antagonist of HMGB1) or PBS was injected into the LV wall. Moreover, cardiac myocytes were cultured and given sustained mechanical stress. Transthoracic echocardiography was performed after the operation and sections for histological analyses were generated from paraffin-embedded hearts. Relevant proteins and genes were detected. Cardiac HMGB1 expression was increased after TAC, which was accompanied by its translocation from nucleus to both cytoplasm and intercellular space. Exogenous HMGB1 aggravated TAC-induced cardiac hypertrophy and cardiac dysfunction, as demonstrated by echocardiographic analyses, histological analyses and foetal cardiac genes detection. Nevertheless, the aforementioned pathological change induced by TAC could partially be reversed by HMGB1 inhibition. Consistent with the in vivo observations, mechanical stress evoked the release and synthesis of HMGB1 in cultured cardiac myocytes. This study indicates that the activated and up-regulated HMGB1 in myocardium, which might partially be derived from cardiac myocytes under pressure overload, may be of crucial importance in pressure overload-induced cardiac hypertrophy and cardiac dysfunction.

  13. Perinatal DDT Exposure Induces Hypertension and Cardiac Hypertrophy in Adult Mice

    PubMed Central

    La Merrill, Michele A.; Sethi, Sunjay; Benard, Ludovic; Moshier, Erin; Haraldsson, Borje; Buettner, Christoph

    2016-01-01

    Background: Dichlorodiphenyltrichloroethane (DDT) was used extensively to control malaria, typhus, body lice, and bubonic plague worldwide, until countries began restricting its use in the 1970s. However, the use of DDT to control vector-borne diseases continues in developing countries. Prenatal DDT exposure is associated with elevated blood pressure in humans. Objective: We hypothesized that perinatal DDT exposure causes hypertension in adult mice. Methods: DDT was administered to C57BL/6J dams from gestational day 11.5 to postnatal day 5. Blood pressure (BP) and myocardial wall thickness were measured in male and female adult offspring. Adult mice were treated with an angiotensin converting enzyme (ACE) inhibitor, captopril, to evaluate sensitivity to amelioration of DDT-associated hypertension by ACE inhibition. We further assessed the influence of DDT exposure on the expression of mRNAs that regulate BP through renal ion transport. Results: Adult mice perinatally exposed to DDT exhibited chronically increased systolic BP, increased myocardial wall thickness, and elevated expression of mRNAs of several renal ion transporters. Captopril completely reversed hypertension in mice perinatally exposed to DDT. Conclusions: These data demonstrate that perinatal exposure to DDT causes hypertension and cardiac hypertrophy in adult offspring. A key mechanism underpinning this hypertension is an overactivated renin angiotensin system because ACE inhibition reverses the hypertension induced by perinatal DDT exposure. Citation: La Merrill M, Sethi S, Benard L, Moshier E, Haraldsson B, Buettner C. 2016. Perinatal DDT exposure induces hypertension and cardiac hypertrophy in adult mice. Environ Health Perspect 124:1722–1727; http://dx.doi.org/10.1289/EHP164 PMID:27325568

  14. Fatty acid utilization in pressure-overload hypertrophied rat hearts

    SciTech Connect

    Reibel, D.K.; O'Rourke, B.

    1986-03-05

    The authors have previously shown that the levels of total tissue coenzyme A and carnitine are reduced in hypertrophied hearts of rats subjected to aortic constriction. It was therefore of interest to determine if these changes were associated with alterations in fatty acid oxidation by the hypertrophied myocardium. Hearts were excised from sham-operated and aortic-constricted rats and perfused at 10 cm H/sub 2/O left atrial filling pressure with a ventricular afterload of 80 cm of H/sub 2/O with buffer containing 1.2 mM /sup 14/C-linoleate. Heart rate and peak systolic pressure were not different in control and hypertrophied hearts. /sup 14/CO/sub 2/ production was linear in both groups of hearts between 10 and 30 minutes of perfusion. The rate of fatty acid oxidation determined by /sup 14/CO/sub 2/ production during this time was 0.728 +/- 0.06 ..mu..moles/min/g dry in control hearts and 0.710 +/- 0.02 ..mu..moles/min/g dry in hypertrophied hearts. Comparable rates of fatty acid oxidation were associated with comparable rates of O/sub 2/ consumption in the two groups of hearts (39.06 +/- 3.50 and 36.78 +/- 2.39 ..mu..moles/g dry/min for control and hypertrophied hearts, respectively). The data indicate that the ability of the hypertrophied heart to oxidize fatty acids under these perfusion conditions is not impaired in spite of significant reductions in tissue levels of coenzyme A and carnitine.

  15. Podocyte hypertrophy precedes apoptosis under experimental diabetic conditions.

    PubMed

    Lee, Sun Ha; Moon, Sung Jin; Paeng, Jisun; Kang, Hye-Young; Nam, Bo Young; Kim, Seonghun; Kim, Chan Ho; Lee, Mi Jung; Oh, Hyung Jung; Park, Jung Tak; Han, Seung Hyeok; Yoo, Tae-Hyun; Kang, Shin-Wook

    2015-08-01

    Podocyte hypertrophy and apoptosis are two hallmarks of diabetic glomeruli, but the sequence in which these processes occur remains a matter of debate. Here we investigated the effects of inhibiting hypertrophy on apoptosis, and vice versa, in both podocytes and glomeruli, under diabetic conditions. Hypertrophy and apoptosis were inhibited using an epidermal growth factor receptor inhibitor (PKI 166) and a pan-caspase inhibitor (zAsp-DCB), respectively. We observed significant increases in the protein expression of p27, p21, phospho-eukaryotic elongation factor 4E-binding protein 1, and phospho-p70 S6 ribosomal protein kinase, in both cultured podocytes exposed to high-glucose (HG) medium, and streptozotocin-induced diabetes mellitus (DM) rat glomeruli. These increases were significantly inhibited by PKI 166, but not by zAsp-DCB. In addition, the amount of protein per cell, the relative cell size, and the glomerular volume were all significantly increased under diabetic conditions, and these changes were also blocked by treatment with PKI 166, but not zAsp-DCB. Increased protein expression of cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase, together with increased Bax/Bcl-2 ratios, were also observed in HG-stimulated podocytes and DM glomeruli. Treatment with either zAsp-DCB or PKI 166 resulted in a significant attenuation of these effects. Both PKI 166 and zAsp-DCB also inhibited the increase in number of apoptotic cells, as assessed by Hoechst 33342 staining and TUNEL assay. Under diabetic conditions, inhibition of podocyte hypertrophy results in attenuated apoptosis, whereas blocking apoptosis has no effect on podocyte hypertrophy, suggesting that podocyte hypertrophy precedes apoptosis.

  16. CD38 promotes angiotensin II-induced cardiac hypertrophy.

    PubMed

    Guan, Xiao-Hui; Hong, Xuan; Zhao, Ning; Liu, Xiao-Hong; Xiao, Yun-Fei; Chen, Ting-Tao; Deng, Li-Bin; Wang, Xiao-Lei; Wang, Jian-Bin; Ji, Guang-Ju; Fu, Mingui; Deng, Ke-Yu; Xin, Hong-Bo

    2017-03-12

    Cardiac hypertrophy is an early hallmark during the clinical course of heart failure and regulated by various signalling pathways. Recently, we observed that mouse embryonic fibroblasts from CD38 knockout mice were significantly resistant to oxidative stress such as H2 O2 -induced injury and hypoxia/reoxygenation-induced injury. In addition, we also found that CD38 knockout mice protected heart from ischaemia reperfusion injury through activating SIRT1/FOXOs-mediated antioxidative stress pathway. However, the role of CD38 in cardiac hypertrophy is not explored. Here, we investigated the roles and mechanisms of CD38 in angiotensin II (Ang-II)-induced cardiac hypertrophy. Following 14 days of Ang-II infusion with osmotic mini-pumps, a comparable hypertension was generated in both of CD38 knockout and wild-type mice. However, the cardiac hypertrophy and fibrosis were much more severe in wild-type mice compared with CD38 knockout mice. Consistently, RNAi-induced knockdown of CD38 decreased the gene expressions of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) and reactive oxygen species generation in Ang-II-stimulated H9c2 cells. In addition, the expression of SIRT3 was elevated in CD38 knockdown H9c2 cells, in which SIRT3 may further activate the FOXO3 antioxidant pathway. The intracellular Ca(2+) release induced by Ang-II markedly decreased in CD38 knockdown H9c2 cells, which might be associated with the decrease of nuclear translocation of NFATc4 and inhibition of ERK/AKT phosphorylation. We concluded that CD38 plays an essential role in cardiac hypertrophy probably via inhibition of SIRT3 expression and activation of Ca(2+) -NFAT signalling pathway. Thus, CD38 may be a novel target for treating cardiac hypertrophy.

  17. Airway smooth muscle growth in asthma: proliferation, hypertrophy, and migration.

    PubMed

    Bentley, J Kelley; Hershenson, Marc B

    2008-01-01

    Increased airway smooth muscle mass is present in fatal and non-fatal asthma. However, little information is available regarding the cellular mechanism (i.e., hyperplasia vs. hypertrophy). Even less information exists regarding the functional consequences of airway smooth muscle remodeling. It would appear that increased airway smooth muscle mass would tend to increase airway narrowing and airflow obstruction. However, the precise effects of increased airway smooth muscle mass on airway narrowing are not known. This review will consider the evidence for airway smooth muscle cell proliferation and hypertrophy in asthma, potential functional effects, and biochemical mechanisms.

  18. Congenital hypertrophy of multiple intrinsic muscles of the foot.

    PubMed

    Shiraishi, Tomohiro; Park, Susam; Niu, Atushi; Hasegawa, Hiromi

    2014-12-01

    Congenital hypertrophy of a single intrinsic muscle of the foot is rare, and as far as we know, only six cases have been reported. We describe a case of congenital anomaly that showed hypertrophy of multiple intrinsic muscles of the foot; the affected muscles were all the intrinsic muscles of the foot except the extensor digitorum brevis or extensor hallucis. Other tissues such as adipose tissue, nervous tissue, or osseous tissue showed no abnormalities. To reduce the volume of the foot we removed parts of the enlarged muscles.

  19. In vitro cultivation and cryopreservation of duck embryonic hepatocytes.

    PubMed

    Schacke, M; Glück, B; Wutzler, P; Sauerbrei, A

    2009-04-01

    Hepatitis B-virucidal testing of biocides in quantitative suspension tests using duck hepatitis B virus (DHBV) requires primary duck embryonic hepatocytes for viral propagation. To improve the test system and availability of these cells, commercial culture plates with different growth surfaces were tested for cell cultivation and different approaches for cryopreservation of hepatocyte suspension were examined. After 12 days of culture, the largest amounts of hepatocytes were grown in CellBIND and TTP plates and CellBIND surface showed the lowest tendency of monolayer detachment nearly comparable with collagen 1-coated CELLCOAT plates. For cryopreservation of hepatocyte suspension, the use of growth medium supplemented with fetal calf serum (FCS) and dimethyl sulfoxide (ME(2)SO), FCS supplemented with ME(2)SO or cryosafe-1 as cryoprotective agents provided the highest rates of surviving cells after thawing. The freezing-thawing process did not significantly reduce the susceptibility of hepatocytes to infection with DHBV. In conclusion, plates without collagen 1 such as CellBIND are recommended for cultivation of primary duck embryonic hepatocytes in infectivity experiments of DHBV for virucidal testing of biocides. The use of cryopreserved hepatocytes is possible when freshly isolated cells from the liver of duck embryos are not available.

  20. New method of hepatocyte transplantation and extracorporeal liver support.

    PubMed Central

    Demetriou, A A; Whiting, J; Levenson, S M; Chowdhury, N R; Schechner, R; Michalski, S; Feldman, D; Chowdhury, J R

    1986-01-01

    A technique has been developed by the authors that allows hepatocyte attachment on collagen-coated microcarriers resulting in prolonged hepatocyte viability and function both in vivo and in vitro. Rat hepatocytes were obtained by portal vein collagenase perfusion. Intraperitoneally transplanted microcarrier-attached normal hepatocytes into congeneic Gunn rats were functioning 3-4 weeks later, as shown by the presence and persistence of conjugated bilirubin in recipient bile, sustained decrease in serum bilirubin, uptake of Tc99m-DESIDA, and morphologic criteria. Intraperitoneal transplantation of normal microcarrier-attached hepatocytes into genetically albumin deficient rats (NAR) resulted in marked increase in plasma albumin levels (6 days without and 21 days with Cyclosporin A immunosuppression). Microcarrier-attached hepatocytes transplanted after 2 weeks of storage at -80 C into congeneic Gunn rats were viable and functional as assessed by criteria outlined above. An extracorporeal liver perfusion system was developed using the microcarrier-attached hepatocytes that was capable of synthesizing and conjugating bilirubin and synthesizing liver-specific proteins. Images FIGS. 5A and B. FIG. 7. FIG. 8. FIG. 9. FIG. 12. PMID:3530153

  1. Isolation of centrolobular and perilobular hepatocytes after phenobarbital treatment

    PubMed Central

    1975-01-01

    Daily phenobarbital (PB) injections, on 3-7 consecutive days, induce an intense proliferation of smooth endoplasmic reticulum (ER) associated with a decrease of the glucose-6-phosphatase activity. This situation first affects the centrolobular hepatocytes, enhancing the degree of liver lobule heterogeneity. This experimental model was used for isolation and further subfractionation of hepatocytes on Ficoll density gradients, as described in the preceding paper. Profiles of protein, DNA, RNA, glycogen, phosphorylase, and glucose-6-phosphatase were determined all along the gradient. Two liver cell populations were distinguished: (a) light hepatocytes (mean density 1.10) present the same morphological characteristics as centrolobular cells, i.e., an abundant smooth ER composed of tubular elements, numerous small mitochondria, and few glycogen particles; (b) heavy hepatocytes (mean density 1.14) are characterized by large and compact glycogen areas and prominent rough endoplasmic cisternae, as are the perilobular cells. After incubation in the Wachstein-Meisel medium, Centrolobular hepatocytes exhibit dispersed reaction sites of glucose-6-phosphatase activity, whereas perilobular cells present a continuous and intense reaction. Morphometric determinations were carried out for both cell populations. Centrolobular PB hepatocytes are considerably enlarged (mean diameter: 23.7 mum); perilobular hepatocytes have a significantly smaller mean diameter of 19.2 mum, which is close to the values of control liver cells. PMID:167029

  2. Protective effect of C-phycocyanin against carbon tetrachloride-induced hepatocyte damage in vitro and in vivo.

    PubMed

    Ou, Yu; Zheng, Shan; Lin, Lin; Jiang, Qizhou; Yang, Xuegan

    2010-04-29

    This study focused on the hepatoprotective activity of C-phycocyanin (C-PC) against carbon tetrachloride-induced hepatocyte damage in vitro and in vivo. In in vitro study, human hepatocyte cell line L02 was used. C-PC showed its capability to reverse CCl(4)-induced L02 cells viability loss, alanine transaminase (ALT) leakage and morphological changes. C-PC also showed the following positive effects: prevent the CCl(4)-induced overproduction of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA); prevent changes in superoxide dismutase (SOD) activity; and reduce glutathione (GSH) level. In vivo, C-PC showed its capability to decrease serum ALT and aspartate transaminase (AST) levels in CCl(4)-induced liver damage in mice. The histological observations supported the results obtained from serum enzymes assays. C-PC also showed the following effects in mice liver: prevent the CCl(4)-induced MDA formation and GSH depletion; prevent SOD and glutathione peroxidase (GSH-Px) activity; and prevent the elevation of transforming growth factor-beta1 (TGF-beta1) and hepatocyte growth factor (HGF) mRNAs. Both the in vitro and in vivo results suggested that C-PC was useful in protecting against CCl(4)-induced hepatocyte damage. One of the mechanisms is believed to be through C-PCs scavenging ability to protect the hepatocytes from free radicals damage induced by CCl(4). In addition, C-PC may be able to block inflammatory infiltration through its anti-inflammatory activities by inhibiting TGF-beta1 and HGF expression.

  3. Lysosomal iron mobilization and induction of the mitochondrial permeability transition in acetaminophen-induced toxicity to mouse hepatocytes.

    PubMed

    Kon, Kazuyoshi; Kim, Jae-Sung; Uchiyama, Akira; Jaeschke, Hartmut; Lemasters, John J

    2010-09-01

    Acetaminophen induces the mitochondrial permeability transition (MPT) in hepatocytes. Reactive oxygen species (ROS) trigger the MPT and play an important role in AAP-induced hepatocellular injury. Because iron is a catalyst for ROS formation, our aim was to investigate the role of chelatable iron in MPT-dependent acetaminophen toxicity to mouse hepatocytes. Hepatocytes were isolated from fasted male C3Heb/FeJ mice. Necrotic cell killing was determined by propidium iodide fluorometry. Mitochondrial membrane potential was visualized by confocal microscopy of tetramethylrhodamine methylester. Chelatable ferrous ion was monitored by calcein quenching, and 70 kDa rhodamine-dextran was used to visualize lysosomes. Cell killing after acetaminophen (10mM) was delayed and decreased by more than half after 6 h by 1mM desferal or 1mM starch-desferal. In a cell-free system, ferrous but not ferric iron quenched calcein fluorescence, an effect reversed by dipyridyl, a membrane-permeable iron chelator. In hepatocytes loaded with calcein, intracellular calcein fluorescence decreased progressively beginning about 4 h after acetaminophen. Mitochondria then depolarized after about 6 h. Dipyridyl (20mM) dequenched calcein fluorescence. Desferal and starch-desferal conjugate prevented acetaminophen-induced calcein quenching and mitochondrial depolarization. As calcein fluorescence became quenched, lysosomes disappeared, consistent with release of iron from ruptured lysosomes. In conclusion, an increase of cytosolic chelatable ferrous iron occurs during acetaminophen hepatotoxicity, which triggers the MPT and cell killing. Disrupted lysosomes are the likely source of iron, and chelation of this iron decreases acetaminophen toxicity to hepatocytes.

  4. Vasectomy reversal.

    PubMed

    Belker, A M

    1987-02-01

    A vasovasostomy may be performed on an outpatient basis with local anesthesia, but also may be performed on an outpatient basis with epidural or general anesthesia. Local anesthesia is preferred by most of my patients, the majority of whom choose this technique. With proper preoperative and intraoperative sedation, patients sleep lightly through most of the procedure. Because of the length of time often required for bilateral microsurgical vasoepididymostomy, epidural or general anesthesia and overnight hospitalization are usually necessary. Factors influencing the preoperative choice for vasovasostomy or vasoepididymostomy in patients undergoing vasectomy reversal are considered. The preoperative planned choice of vasovasostomy or vasoepididymostomy for patients having vasectomy reversal described herein does not have the support of all urologists who regularly perform these procedures. My present approach has evolved as the data reported in Tables 1 and 2 have become available, but it may change as new information is evaluated. However, it offers a logical method for planning choices of anesthesia and inpatient or outpatient status for patients undergoing vasectomy reversal procedures.

  5. Dietary copper supplementation reverses hypertrophic cardiomyopathy induced by chronic pressure overload in mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustained pressure overload causes cardiac hypertrophy and the transition to heart failure. We show here that dietary supplementation with physiologically relevant levels of copper (Cu) reverses pre-established hypertrophic cardiomyopathy in the presence of pressure overload induced by ascending aor...

  6. Hepatocytic parental progenitor cells of rat small hepatocytes maintain self-renewal capability after long-term culture

    PubMed Central

    Ishii, Masayuki; Kino, Junichi; Ichinohe, Norihisa; Tanimizu, Naoki; Ninomiya, Takafumi; Suzuki, Hiromu; Mizuguchi, Toru; Hirata, Koichi; Mitaka, Toshihiro

    2017-01-01

    The liver has a variety of functions for maintaining homeostasis, and hepatocytes play a major role. In contrast with the high regenerative capacity of mature hepatocytes (MHs) in vivo, they have not been successfully expanded ex vivo. Here we demonstrate that CD44-positive cells sorted from small hepatocyte (SH) colonies derived from a healthy adult rat liver can proliferate on a Matrigel-coated dish in serum-free chemically defined medium; in addition, a subpopulation of the cells can divide more than 50 times in a period of 17 weeks every 4-week-passage. The passage cells retained the capability to recover highly differentiated functions, such as glycogen storage, CYP activity and bile secretion. When Matrigel-treated cells from the third passage were transplanted into retrorsine/partial hepatectomy-treated rat livers, the cells engrafted to differentiate into MHs and cholangiocytes. These results suggest that long-term cultured CD44+ SHs retain hepatocytic characteristics in vitro and the capability to differentiate into hepatocytes and cholangiocytes in vivo. Thus, a newly identified subpopulation of MHs possessing the attributes of hepatocytic stem/progenitor cells can be passaged several times without losing hepatocytic characteristics.

  7. Hepatocyte growth factor incorporated chitosan nanoparticles augment the differentiation of stem cell into hepatocytes for the recovery of liver cirrhosis in mice

    PubMed Central

    2011-01-01

    Background Short half-life and low levels of growth factors in the niche of injured microenvironment necessitates the exogenous and sustainable delivery of growth factors along with stem cells to augment the regeneration of injured tissues. Methods Here, recombinant human hepatocyte growth factor (HGF) was incorporated into chitosan nanoparticles (CNP) by ionic gelation method and studied for its morphological and physiological characteristics. Cirrhotic mice received either hematopoietic stem cells (HSC) or mesenchymal stemcells (MSC) with or without HGF incorporated chitosan nanoparticles (HGF-CNP) and saline as control. Biochemical, histological, immunostaining and gene expression assays were carried out using serum and liver tissue samples. One way analysis of variance was used for statics application Results Serum levels of selected liver protein and enzymes were significantly increased in the combination of MSC and HGF-CNP (MSC+HGF-CNP) treated group. Immunopositive staining for albumin (Alb) and cytokeratin 18 (CK18), and reverse transcription-polymerase chain reaction (RT-PCR) for Alb, alpha fetoprotein (AFP), CK18, cytokeratin 19 (CK19) ascertained that MSC-HGF-CNP treatment could be an effective combination to repopulate liver parenchymal cells in the liver cirrhosis. Zymogram and western blotting for matrix metalloproteinases 2 and 9 (MMP2 and MMP9) revealed that MMP2 actively involved in the fibrolysis of cirrhotic tissue. Immunostaining for alpha smooth muscle actin (αSMA) and type I collagen showed decreased expression in the MSC+HGF-CNP treatment. These results indicated that HGF-CNP enhanced the differentiation of stem cells into hepatocytes and supported the reversal of fibrolysis of extracellular matrix (ECM). Conclusion Bone marrow stem cells were isolated, characterized and transplanted in mice model. Biodegradable biopolymeric nanoparticles were prepared with the pleotrophic protein molecule and it worked well for the differentiation of stem

  8. Subaortic and midventricular obstructive hypertrophic cardiomyopathy with extreme segmental hypertrophy

    PubMed Central

    Efthimiadis, Georgios K; Giannakoulas, Georgios; Parcharidou, Despina G; Ziakas, Antonios G; Papadopoulos, Christodoulos E; Karoulas, Takis; Pliakos, Christodoulos; Parcharidis, Georgios

    2007-01-01

    Background Subaortic and midventricular hypertrophic cardiomyopathy in a patient with extreme segmental hypertrophy exceeding the usual maximum wall thickness reported in the literature is a rare phenomenon. Case Presentation A 19-year-old man with recently diagnosed hypertrophic cardiomyopathy (HCM) was referred for sudden death risk assessment. The patient had mild exertional dyspnea (New York Heart Association functional class II), but without syncope or chest pain. There was no family history of HCM or sudden death. A two dimensional echocardiogram revealed an asymmetric type of LV hypertrophy; anterior ventricular septum = 49 mm; posterior ventricular septum = 20 mm; anterolateral free wall = 12 mm; and posterior free wall = 6 mm. The patient had 2 types of obstruction; a LV outflow obstruction due to systolic anterior motion of both mitral leaflets (Doppler-estimated 38 mm Hg gradient at rest); and a midventricular obstruction (Doppler-estimated 43 mm Hg gradient), but without apical aneurysm or dyskinesia. The patient had a normal blood pressure response on exercise test and no episodes of non-sustained ventricular tachycardia in 24-h ECG recording. Cardiac MRI showed a gross late enhancement at the hypertrophied septum. Based on the extreme degree of LV hypertrophy and the myocardial hyperenhancement, an implantation of a cardioverter-defibrillator was recommended prophylactically for primary prevention of sudden death. Conclusion Midventricular HCM is an infrequent phenotype, but may be associated with an apical aneurysm and progression to systolic dysfunction (end-stage HCM). PMID:17349063

  9. Histopathological study on myocardial hypertrophy associated with ischemic heart disease.

    PubMed

    Ishijima, M

    1990-06-01

    The mode and causes of myocardial hypertrophy occurring in association with ischemic heart disease were studied. The investigation involved autopsied hearts (15 cases of subendocardial infarction, 27 of transmural infarction, 20 of non-infarcted three vessel disease and 17 controls) and biopsied materials obtained during coronary-aorta bypass graft surgery (23 patients with angina pectoris and 46 with myocardial infarction). The subendocardial infarction group showed most marked myocardial hypertrophy that reflected extensive infarction and fibrosis, dilatation of the left ventricular cavity and the loss of myocytes. Despite a marked decrease in the number of myocyte layers, the residual myocardium of the left ventricle was uniformly hypertrophic, accompanied by an increase in the heart weight. The larger the area of fibrosis, the more marked was myocardial hypertrophy irrespective of the luminal diameter of the responsible coronary artery. These findings indicate that myocardial hypertrophy associated with ischemic heart disease is enhanced by the compensatory mechanisms for a decrease in the contractile myocardium due to fibrosis.

  10. Hyperplasia and Hypertrophy of Pacinian Corpuscles: A Case Report.

    PubMed

    García, Fernando Cano; Acosta, Dalia Rodríguez; Diaz González, José Manuel; Lima, Marcela Saeb

    2015-08-01

    The proliferation of Pacinian corpuscles is a rare benign lesion that occurs frequently in the fingers of hands, with the only clinical sign of pain when a drastic temperature change happens. A case of an extremely rare lesion in which we observed hypertrophy and hyperplasia of Pacinian corpuscles has been reported.

  11. Antileukotrienes in adenotonsillar hypertrophy: a review of the literature.

    PubMed

    Kar, Murat; Altıntoprak, Niyazi; Muluk, Nuray Bayar; Ulusoy, Seckin; Bafaqeeh, Sameer Ali; Cingi, Cemal

    2016-12-01

    We assessed the use of antileukotrienes for treating adenotonsillar hypertrophy. We reviewed the current literature on the anatomy of adenotonsillar tissue, adenotonsillar hypertrophy/hyperplasia (and the associated pathophysiology and symptoms), and the effects of antileukotrienes used to treat adenotonsillar hypertrophy. Leukotrienes (LTs) are inflammatory mediators produced by a number of cell types, including mast cells, eosinophils, basophils, macrophages, and monocytes. There are several types (e.g., LTA4, LTB4, LTC4, LTD4, and LTE4). By competitive binding to the cysLT1 receptor, LT-receptor antagonist drugs such as montelukast, zafirlukast, and pranlukast block the effects of cySHLTs, improving the symptoms of some chronic respiratory diseases. High numbers of LT receptors have been found in the tonsils of children with obstructive sleep apnea. Antileukotrienes reduce the apnea-hypopnea index and adenotonsillar inflammation. Antileukotrienes may be useful for children with adenotonsillar hypertrophy due to their anti-inflammatory effects, which help to reduce adenotonsillar inflammation.

  12. Hemifacial hypertrophy: Exploring new avenues of treatment modalities

    PubMed Central

    Nandimath, Santosh Ashok; Rajkumar, G. C.; Nayak, Tulasi; Ashwin, D. P.; Rudresh, K. B.; Prashanth, R.

    2016-01-01

    Congenital hemihyperplasia is a rare developmental disorder characterized by unilateral overgrowth of one or more body parts resulting in marked asymmetry. We are reporting here, a case of true hemifacial hypertrophy in a young female adult highlighting the clinical features and possible treatment options. PMID:28163490

  13. Dance band on the Titanic: biomechanical signaling in cardiac hypertrophy.

    PubMed

    Sussman, Mark A; McCulloch, Andrew; Borg, Thomas K

    2002-11-15

    Biomechanical signaling is a complex interaction of both intracellular and extracellular components. Both passive and active components are involved in the extracellular environment to signal through specific receptors to multiple signaling pathways. This review provides an overview of extracellular matrix, specific receptors, and signaling pathways for biomechanical stimulation in cardiac hypertrophy.

  14. Bilateral temporalis muscle hypertrophy--two case reports.

    PubMed

    Kar, Jugal Kishore; Kar, Manoranjan; Maiti, Saswati; Sen, Eva

    2012-05-01

    Isolated idiopathic bilateral temporalis muscle hypertrophy is a very rare clinical entity. It can change the facial appearance that manifests itself as a morphopsychological conflict for the subject, which is termed as 'Minotaur syndrome' in the medical literature. Here one such case is reported. The second patient sought medical attention for fear of malignancy.

  15. Muscle Hypertrophy in Prepubescent Tennis Players: A Segmentation MRI Study

    PubMed Central

    Sanchis-Moysi, Joaquin; Idoate, Fernando; Serrano-Sanchez, Jose A.; Dorado, Cecilia; Calbet, Jose A. L.

    2012-01-01

    Purpose To asses if tennis at prepubertal age elicits the hypertrophy of dominant arm muscles. Methods The volume of the muscles of both arms was determined using magnetic resonance imaging (MRI) in 7 male prepubertal tennis players (TP) and 7 non-active control subjects (CG) (mean age 11.0±0.8 years, Tanner 1–2). Results TP had 13% greater total muscle volume in the dominant than in the contralateral arm. The magnitude of inter-arm asymmetry was greater in TP than in CG (13 vs 3%, P<0.001). The dominant arm of TP was 16% greater than the dominant arm of CG (P<0.01), whilst non-dominant arms had similar total muscle volumes in both groups (P = 0.25), after accounting for height as covariate. In TP, dominant deltoid (11%), forearm supinator (55%) and forearm flexors (21%) and extensors (25%) were hypertrophied compared to the contralateral arm (P<0.05). In CG, the dominant supinator muscle was bigger than its contralateral homonimous (63%, P<0.05). Conclusions Tennis at prepubertal age is associated with marked hypertrophy of the dominant arm, leading to a marked level of asymmetry (+13%), much greater than observed in non-active controls (+3%). Therefore, tennis particpation at prepubertal age is associated with increased muscle volumes in dominant compared to the non-dominant arm, likely due to selectively hypertrophy of the loaded muscles. PMID:22428074

  16. Elucidation of MRAS-mediated Noonan syndrome with cardiac hypertrophy.

    PubMed

    Higgins, Erin M; Bos, J Martijn; Mason-Suares, Heather; Tester, David J; Ackerman, Jaeger P; MacRae, Calum A; Sol-Church, Katia; Gripp, Karen W; Urrutia, Raul; Ackerman, Michael J

    2017-03-09

    Noonan syndrome (NS; MIM 163950) is an autosomal dominant disorder and a member of a family of developmental disorders termed "RASopathies," which are caused mainly by gain-of-function mutations in genes encoding RAS/MAPK signaling pathway proteins. Whole exome sequencing (WES) and trio-based genomic triangulation of a 15-year-old female with a clinical diagnosis of NS and concomitant cardiac hypertrophy and her unaffected parents identified a de novo variant in MRAS-encoded RAS-related protein 3 as the cause of her disease. Mutation analysis using in silico mutation prediction tools and molecular dynamics simulations predicted the identified variant, p.Gly23Val-MRAS, to be damaging to normal protein function and adversely affect effector interaction regions and the GTP-binding site. Subsequent ectopic expression experiments revealed a 40-fold increase in MRAS activation for p.Gly23Val-MRAS compared with WT-MRAS. Additional biochemical assays demonstrated enhanced activation of both RAS/MAPK pathway signaling and downstream gene expression in cells expressing p.Gly23Val-MRAS. Mutational analysis of MRAS in a cohort of 109 unrelated patients with phenotype-positive/genotype-negative NS and cardiac hypertrophy yielded another patient with a sporadic de novo MRAS variant (p.Thr68Ile, c.203C>T). Herein, we describe the discovery of mutations in MRAS in patients with NS and cardiac hypertrophy, establishing MRAS as the newest NS with cardiac hypertrophy-susceptibility gene.

  17. Gene Coexpression Network Topology of Cardiac Development, Hypertrophy, and Failure

    PubMed Central

    Dewey, Frederick E.; Perez, Marco V.; Wheeler, Matthew T.; Watt, Clifton; Spin, Joshua; Langfelder, Peter; Horvath, Stephen; Hannenhalli, Sridhar; Cappola, Thomas P.; Ashley, Euan A.

    2011-01-01

    Background Network analysis techniques allow a more accurate reflection of underlying systems biology to be realized than traditional unidimensional molecular biology approaches. Here, using gene coexpression network analysis, we define the gene expression network topology of cardiac hypertrophy and failure and the extent of recapitulation of fetal gene expression programs in failing and hypertrophied adult myocardium. Methods and Results We assembled all myocardial transcript data in the Gene Expression Omnibus (n = 1617). Since hierarchical analysis revealed species had primacy over disease clustering, we focused this analysis on the most complete (murine) dataset (n = 478). Using gene coexpression network analysis, we derived functional modules, regulatory mediators and higher order topological relationships between genes and identified 50 gene co-expression modules in developing myocardium that were not present in normal adult tissue. We found that known gene expression markers of myocardial adaptation were members of upregulated modules but not hub genes. We identified ZIC2 as a novel transcription factor associated with coexpression modules common to developing and failing myocardium. Of 50 fetal gene co-expression modules, three (6%) were reproduced in hypertrophied myocardium and seven (14%) were reproduced in failing myocardium. One fetal module was common to both failing and hypertrophied myocardium. Conclusions Network modeling allows systems analysis of cardiovascular development and disease. While we did not find evidence for a global coordinated program of fetal gene expression in adult myocardial adaptation, our analysis revealed specific gene expression modules active during both development and disease and specific candidates for their regulation. PMID:21127201

  18. Erbin is a negative modulator of cardiac hypertrophy.

    PubMed

    Rachmin, Inbal; Tshori, Sagi; Smith, Yoav; Oppenheim, Amit; Marchetto, Sylvie; Kay, Gillian; Foo, Roger S-Y; Dagan, Noa; Golomb, Eliahu; Gilon, Dan; Borg, Jean-Paul; Razin, Ehud

    2014-04-22

    ErbB2 interacting protein (Erbin) is a widely expressed protein and participates in inhibition of several intracellular signaling pathways. Its mRNA has been found to be present in relatively high levels in the heart. However, its physiological role in the heart has not been explored. In the present work, we elucidated the role of Erbin in cardiac hypertrophy. Cardiac hypertrophy was induced in mice either by isoproterenol administration or by aortic constriction. The level of Erbin was significantly decreased in both models. Erbin(-/-) mice rapidly develop decompensated cardiac hypertrophy, and following severe pressure overload all Erbin(-/-) mice died from heart failure. Down-regulation of Erbin expression was also observed in biopsies derived from human failing hearts. It is known that Erbin inhibits Ras-mediated activation of the extracellular signal-regulated kinase (ERK) by binding to Soc-2 suppressor of clear homolog (Shoc2). Our data clearly show that ERK phosphorylation is enhanced in the heart tissues of Erbin(-/-) mice. Furthermore, we clearly demonstrate here that Erbin associates with Shoc2 in both whole hearts and in cardiomyocytes, and that in the absence of Erbin, Raf is phosphorylated and binds Shoc2, resulting in ERK phosphorylation. In conclusion, Erbin is an inhibitor of pathological cardiac hypertrophy, and this inhibition is mediated, at least in part, by modulating ERK signaling.

  19. Erbin is a negative modulator of cardiac hypertrophy

    PubMed Central

    Rachmin, Inbal; Tshori, Sagi; Smith, Yoav; Oppenheim, Amit; Marchetto, Sylvie; Kay, Gillian; Foo, Roger S.-Y.; Dagan, Noa; Golomb, Eliahu; Gilon, Dan; Borg, Jean-Paul; Razin, Ehud

    2014-01-01

    ErbB2 interacting protein (Erbin) is a widely expressed protein and participates in inhibition of several intracellular signaling pathways. Its mRNA has been found to be present in relatively high levels in the heart. However, its physiological role in the heart has not been explored. In the present work, we elucidated the role of Erbin in cardiac hypertrophy. Cardiac hypertrophy was induced in mice either by isoproterenol administration or by aortic constriction. The level of Erbin was significantly decreased in both models. Erbin−/− mice rapidly develop decompensated cardiac hypertrophy, and following severe pressure overload all Erbin−/− mice died from heart failure. Down-regulation of Erbin expression was also observed in biopsies derived from human failing hearts. It is known that Erbin inhibits Ras-mediated activation of the extracellular signal-regulated kinase (ERK) by binding to Soc-2 suppressor of clear homolog (Shoc2). Our data clearly show that ERK phosphorylation is enhanced in the heart tissues of Erbin−/− mice. Furthermore, we clearly demonstrate here that Erbin associates with Shoc2 in both whole hearts and in cardiomyocytes, and that in the absence of Erbin, Raf is phosphorylated and binds Shoc2, resulting in ERK phosphorylation. In conclusion, Erbin is an inhibitor of pathological cardiac hypertrophy, and this inhibition is mediated, at least in part, by modulating ERK signaling. PMID:24711380

  20. Hepatocyte Growth Factor Regulates Angiotensin Converting Enzyme Expression*

    PubMed Central

    Day, Regina M.; Thiel, Gerald; Lum, Julie; Chévere, Rubén D.; Yang, Yongzhen; Stevens, Joanne; Sibert, Laura; Fanburg, Barry L.

    2008-01-01

    Hepatocyte growth factor (HGF) is a mitogen, morphogen, and motogen that functions in tissue healing and acts as an anti-fibrotic factor. The mechanism for this is not well understood. Recent studies implicate somatic angiotensin-converting enzyme (ACE) in fibrosis. We examined the effects of HGF on ACE expression in bovine pulmonary artery endothelial cells (BPAEC). Short term treatment of BPAEC with HGF transiently increased both ACE mRNA (3 h) and activity (24 h), as determined by ACE protease assays and reverse transcription-PCR. Incubation of BPAEC with HGF for longer periods suppressed ACE mRNA (6 h) and activity (72 h). In contrast, phorbol ester (PMA) treatment produced sustained increase in ACE mRNA and activity. We examined the short term molecular effects of HGF on ACE using PMA for comparison. HGF and PMA increased transcription from a luciferase reporter with the core ACE promoter, which contains a composite binding site for SP1/3 and Egr-1. Immunocytochemistry and electrophoretic mobility shift assay showed that both HGF and PMA increased Egr-1 binding. HGF also increased SP3 binding, as measured by EMSA. However, HGF and PMA increased the cellular activity of only Egr-1, not SP3, as measured by luciferase reporter assays. Deletion of the Egr-1 site in the reporter construct completely abrogated HGF-induced transcription but only ~50% of PMA-induced activity. Expression of dominant negative Egr-1 and SP3 blocked up-regulation of the ACE promoter by HGF but only reduced up-regulation by PMA. These results show that HGF transiently increases gene transcription of ACE via activation of Egr-1, whereas PMA regulation involves Egr-1 and additional factor(s). PMID:14679188

  1. Exercise preconditioning attenuates pressure overload-induced pathological cardiac hypertrophy

    PubMed Central

    Xu, Tongyi; Tang, Hao; Zhang, Ben; Cai, Chengliang; Liu, Xiaohong; Han, Qingqi; Zou, Liangjian

    2015-01-01

    Pathological cardiac hypertrophy, a common response of the heart to a variety of cardiovascular diseases, is typically associated with myocytes remodeling and fibrotic replacement, cardiac dysfunction. Exercise preconditioning (EP) increases the myocardial mechanical load and enhances tolerance of cardiac ischemia-reperfusion injury (IRI), however, is less reported in pathological cardiac hypertrophy. To determine the effect of EP in pathological cardiac hypertrophy, Male 10-wk-old Sprague-Dawley rats (n=30) were subjected to 4 weeks of EP followed by 4-8 weeks of pressure overload (transverse aortic constriction, TAC) to induce pathological remodeling. TAC in untrained controls (n=30) led to pathological cardiac hypertrophy, depressed systolic function. We observed that left ventricular wall thickness in end diastole, heart size, heart weight-to-body weight ratio, heart weight-to-tibia length ratio, cross-sectional area of cardiomyocytes and the reactivation of fetal genes (atrial natriuretic peptide and brain natriuretic peptide) were markedly increased, meanwhile left ventricular internal dimension at end-diastole, systolic function were significantly decreased by TAC at 4 wks after operation (P < 0.01), all of which were effectively inhibited by EP treatment (P < 0.05), but the differences of these parameters were decreased at 8 wks after operation. Furthermore, EP treatment inhibited degradation of IκBα, and decreased NF-κB p65 subunit levels in the nuclear fraction, and then reduced IL2 levels in the myocardium of rats subject to TAC. EP can effectively attenuate pathological cardiac hypertrophic responses induced by TAC possibly through inhibition of degradation of IκB and blockade of the NF-κB signaling pathway in the early stage of pathological cardiac hypertrophy. PMID:25755743

  2. Effective fiber hypertrophy in satellite cell-depleted skeletal muscle.

    PubMed

    McCarthy, John J; Mula, Jyothi; Miyazaki, Mitsunori; Erfani, Rod; Garrison, Kelcye; Farooqui, Amreen B; Srikuea, Ratchakrit; Lawson, Benjamin A; Grimes, Barry; Keller, Charles; Van Zant, Gary; Campbell, Kenneth S; Esser, Karyn A; Dupont-Versteegden, Esther E; Peterson, Charlotte A

    2011-09-01

    An important unresolved question in skeletal muscle plasticity is whether satellite cells are necessary for muscle fiber hypertrophy. To address this issue, a novel mouse strain (Pax7-DTA) was created which enabled the conditional ablation of >90% of satellite cells in mature skeletal muscle following tamoxifen administration. To test the hypothesis that satellite cells are necessary for skeletal muscle hypertrophy, the plantaris muscle of adult Pax7-DTA mice was subjected to mechanical overload by surgical removal of the synergist muscle. Following two weeks of overload, satellite cell-depleted muscle showed the same increases in muscle mass (approximately twofold) and fiber cross-sectional area with hypertrophy as observed in the vehicle-treated group. The typical increase in myonuclei with hypertrophy was absent in satellite cell-depleted fibers, resulting in expansion of the myonuclear domain. Consistent with lack of nuclear addition to enlarged fibers, long-term BrdU labeling showed a significant reduction in the number of BrdU-positive myonuclei in satellite cell-depleted muscle compared with vehicle-treated muscle. Single fiber functional analyses showed no difference in specific force, Ca(2+) sensitivity, rate of cross-bridge cycling and cooperativity between hypertrophied fibers from vehicle and tamoxifen-treated groups. Although a small component of the hypertrophic response, both fiber hyperplasia and regeneration were significantly blunted following satellite cell depletion, indicating a distinct requirement for satellite cells during these processes. These results provide convincing evidence that skeletal muscle fibers are capable of mounting a robust hypertrophic response to mechanical overload that is not dependent on satellite cells.

  3. Phosphorylation of ribosomal protein S6 mediates compensatory renal hypertrophy.

    PubMed

    Xu, Jinxian; Chen, Jianchun; Dong, Zheng; Meyuhas, Oded; Chen, Jian-Kang

    2015-03-01

    The molecular mechanism underlying renal hypertrophy and progressive nephron damage remains poorly understood. Here we generated congenic ribosomal protein S6 (rpS6) knock-in mice expressing nonphosphorylatable rpS6 and found that uninephrectomy-induced renal hypertrophy was significantly blunted in these knock-in mice. Uninephrectomy-induced increases in cyclin D1 and decreases in cyclin E in the remaining kidney were attenuated in the knock-in mice compared with their wild-type littermates. Uninephrectomy induced rpS6 phosphorylation in the wild-type mice; however, no rpS6 phosphorylation was detected in uninephrectomized or sham-operated knock-in mice. Nonetheless, uninephrectomy stimulated comparable 4E-BP1 phosphorylation in both knock-in and wild-type mice, indicating that mTORC1 was still activated in the knock-in mice. Moreover, the mTORC1 inhibitor rapamycin prevented both rpS6 and 4E-BP1 phosphorylation, significantly blunted uninephrectomy-induced renal hypertrophy in wild-type mice, but did not prevent residual renal hypertrophy despite inhibiting 4E-BP1 phosphorylation in uninephrectomized knock-in mice. Thus, both genetic and pharmacological approaches unequivocally demonstrate that phosphorylated rpS6 is a downstream effector of the mTORC1-S6K1 signaling pathway mediating renal hypertrophy. Hence, rpS6 phosphorylation facilitates the increase in cyclin D1 and decrease in cyclin E1 that underlie the hypertrophic nature of uninephrectomy-induced kidney growth.

  4. Stimulus specific changes of energy metabolism in hypertrophied heart.

    PubMed

    Rimbaud, S; Sanchez, H; Garnier, A; Fortin, D; Bigard, X; Veksler, V; Ventura-Clapier, R

    2009-06-01

    Cardiac energy metabolism is a determinant of the response to hypertrophic stimuli. To investigate how it responds to physiological or pathological stimuli, we compared the energetic status in models of hypertrophy induced by physiological stimuli (pregnancy or treadmill running) and by pathological stimulus (spontaneously hypertensive rats, SHR) in 15 week-old female rats, leading to a 10% cardiac hypertrophy. Late stage of compensated hypertrophy was also studied in 25 week-old SHR (35% of hypertrophy). Markers of cardiac remodelling did not follow a unique pattern of expression: in trained rats, only ANF was increased; in gravid rats, calcineurin activation and BNP expression were reduced while beta-MHC expression was enhanced; all markers were clearly up-regulated in 25 week-old SHR. Respiration of permeabilized fibers revealed a 17% increase in oxidative capacity in trained rats only. Mitochondrial enzyme activities, expression of the master regulator PGC-1alpha and mitochondrial transcription factor A, and content of mitochondrial DNA were not consistently changed, suggesting that compensated hypertrophy does not involve alterations of mitochondrial biogenesis. Mitochondrial fatty acid utilization tended to increase in trained rats and decreased by 14% in 15 week-old SHR. Expression of markers of lipid oxidation, PPARalpha and its down-stream targets MCAD and CPTI, was up-regulated after training and tended to decrease in gravid and 15 week-old SHR rats. Taken together these results show that there is no univocal pattern of cardiac adaptation in response to physiological or pathological hypertrophic stimuli, suggesting that other factors could play a role in determining adaptation of energy metabolism to increased workload.

  5. Cinnamaldehyde attenuates pressure overload-induced cardiac hypertrophy

    PubMed Central

    Yang, Liu; Wu, Qing-Qing; Liu, Yuan; Hu, Zhe-Fu; Bian, Zhou-Yan; Tang, Qi-Zhu

    2015-01-01

    Background: Cinnamaldehyde is a major bioactive compound isolated from the leaves of Cinnamomum osmophloeum. Studies have demonstrated that cinnamaldehyde has anti-bacterial activity, anti-tumorigenic effect, immunomodulatory effect, anti-fungal activity, anti-oxidative effect, anti-inflammatory and anti-diabetic effect. It has been proven that Cinnamaldehyde improves ischemia/reperfusion injury of pre-treatment. However, little is known about the effect of cinnamaldehyde on cardiac hypertrophy. Methods: Aortic banding (AB) was performed to induce cardiac hypertrophy in mice. Cinnamaldehyde premixed in diets was administered to mice after one week of AB. Echocardiography and catheter-based measurements of hemodynamic parameters were performed at week 7 after starting cinnamaldehyde (8 weeks after surgery). The extent of cardiac hypertrophy was evaluated by pathological and molecular analyses of heart samples. Meanwhile, the effect of cinnamaldehyde on myocardial hypertrophy, fibrosis and dysfunction induced by AB was investigated, as was assessed by heart weigh/body weight, lung weight/body weight, heart weight/tibia length, echocardiographic and haemodynamic parameters, histological analysis, and gene expression of hypertrophic and fibrotic markers. Results: Our data demonstrated that echocardiography and catheter-based measurements of hemodynamic parameters at week 7 revealed the amelioration of systolic and diastolic abnormalities by cinnamaldehyde intervention. Cardiac fibrosis in AB mice was also decreased by cinnamaldehyde. Moreover, the beneficial effect of cinnamaldehyde was associated with the normalization in gene expression of hypertrophic and fibrotic markers. Further studies showed that pressure overload significantly induced the activation of extracellular signal-regulated kinase (ERK) signaling pathway, which was blocked by cinnamaldehyde. Conclusion: Cinnamaldehyde may be able to retard the progression of cardiac hypertrophy and fibrosis, probably

  6. Coculture and Long-Term Maintenance of Hepatocytes.

    PubMed

    Cohen, Merav; Levy, Gahl; Nahmias, Yaakov

    2015-01-01

    The liver is the largest internal organ in mammals, serving a wide spectrum of vital functions. Loss of liver function due to drug toxicity, progressive fatty liver disease, or viral infection is a major cause of death in the United States of America. Pharmaceutical and cosmetic toxicity screening, basic research and the development of bioartificial liver devices require long-term hepatocyte culture techniques that sustain hepatocyte morphology and function. In recent years, several techniques have been developed that can support high levels of liver-specific gene expression, metabolic function, and synthetic activity for several weeks in culture. These include the collagen double gel configuration, hepatocyte spheroids, coculture with nonparenchymal cells, and micropatterned cocultures. This chapter will cover the current status of hepatocyte culture techniques, including media formulation, oxygen supply, and heterotypic cell-cell interactions.

  7. Direct reprogramming of human fibroblasts to functional and expandable hepatocytes.

    PubMed

    Huang, Pengyu; Zhang, Ludi; Gao, Yimeng; He, Zhiying; Yao, Dan; Wu, Zhitao; Cen, Jin; Chen, Xiaotao; Liu, Changcheng; Hu, Yiping; Lai, Dongmei; Hu, Zhenlei; Chen, Li; Zhang, Ying; Cheng, Xin; Ma, Xiaojun; Pan, Guoyu; Wang, Xin; Hui, Lijian

    2014-03-06

    The generation of large numbers of functional human hepatocytes for cell-based approaches to liver disease is an important and unmet goal. Direct reprogramming of fibroblasts to hepatic lineages could offer a solution to this problem but so far has only been achieved with mouse cells. Here, we generated human induced hepatocytes (hiHeps) from fibroblasts by lentiviral expression of FOXA3, HNF1A, and HNF4A. hiHeps express hepatic gene programs, can be expanded in vitro, and display functions characteristic of mature hepatocytes, including cytochrome P450 enzyme activity and biliary drug clearance. Upon transplantation into mice with concanavalin-A-induced acute liver failure and fatal metabolic liver disease due to fumarylacetoacetate dehydrolase (Fah) deficiency, hiHeps restore the liver function and prolong survival. Collectively, our results demonstrate successful lineage conversion of nonhepatic human cells into mature hepatocytes with potential for biomedical and pharmaceutical applications.

  8. Toxicity of ethacrynic acid in isolated rat hepatocytes.

    PubMed

    Yamamoto, K; Masubuchi, Y; Narimatsu, S; Kobayashi, S; Horie, T

    2002-04-01

    Ethacrynic acid, a loop diuretic drug, caused lipid peroxidation in isolated rat hepatocytes. The thiobarbituric acid reactive substances (TBARS) formation showed a good correlation with the leakage of glutamic-oxaloacetic acid transaminase (GOT) from the hepatocytes. The addition of antioxidants such as N, N'-diphenyl-p-phenylenediamine (DPPD) and promethazine to the isolated rat hepatocyte suspension containing ethacrynic acid prevented the lipid peroxidation and decreased the GOT leakage to some extent. SKF-525A inhibited the oxidative metabolism of ethacrynic acid and decreased the TBARS formation, suggesting that the lipid peroxidation was caused by the oxidative metabolism. The intracellular reduced glutathione markedly decreased in the hepatocyte suspension containing ethacrynic acid and the hepatocellular protein sulfhydryls were decreased, which was negatively correlated with the GOT leakage. Thus the ethacrynic acid-induced hepatotoxicity was found to be related to the lipid peroxidation and the decrease of cellular protein sulfhydryls.

  9. Intracytoplasmic Crystalline Inclusions in the Hepatocytes of an Antelope

    DTIC Science & Technology

    2010-01-01

    hepatocytes of a 13-year-old female Thomson’s gazelle . Histologically, multifocal to coalescing areas of many hepatocytes contained large cytoplasmic...hepatocellular crystalline inclusions in a gazelle . 2. Case Description A 13-year-old female Thomson’s gazelle (Eudorcas thomsoni) from a zoo was presented to...dead and had a history of severe parasitism. Postmortem examination revealed sparse body fat store in the gazelle . There was bilateral enlargement of

  10. Liver Hypertrophy After Percutaneous Portal Vein Embolization: Comparison of N-Butyl-2-Cyanocrylate Versus Sodium Acrylate-Vinyl Alcohol Copolymer Particles in a Swine Model

    SciTech Connect

    Tsoumakidou, Georgia; Theocharis, Stamatis; Ptohis, Nikolaos Alexopoulou, Efthimia; Mantziaras, George; Kelekis, Nikolaos L. Brountzos, Elias N.

    2011-10-15

    Purpose: Percutaneous portal vein embolization (PPVE) induces hypertrophy of the future liver remnant before hepatic resection. The ideal embolic material has not yet been determined. We compared N-butyl-2-cyanocrylate (NBCA) with sodium acrylate-vinyl alcohol copolymer particles using a swine model. Materials and Methods: Twelve pigs underwent PPVE. Six pigs (group A) were embolized with NBCA, and 6 pigs (group B) were embolized with sodium acrylate-vinyl alcohol copolymer particles. Computed tomographic volumetry of the embolized lobe (EL) and the nonembolized lobe (NEL), along with liver function tests, was performed before and at 14 and 28 days after embolization. Tissue samples from both lobes were taken 14 and 28 days after PPVE. Results: NEL-volume and NEL-ratio increases were significantly higher in group A at 14 and 28 days after PPVE (78 and 52% and 91 and 66%, respectively) than in group B (32 and 12% and 28 and 10%, respectively) (p < 0.05). Percent change of the EL-volume was significantly higher for group A at 28 days after PPVE. No statistically significant difference was found between the groups regarding hepatocyte proliferation on the NEL and apoptosis on the EL at both time intervals. Conclusion: PPVE using NBCA is more efficient and causes more NEL hypertrophy than microspheres.

  11. Salvianolate Protects Hepatocytes from Oxidative Stress by Attenuating Mitochondrial Injury

    PubMed Central

    Zhao, Qiang; Peng, Yuan; Huang, Kai; Lei, Yang; Liu, Hong-Liang; Tao, Yan-Yan

    2016-01-01

    Salvianolate is widely used to treat angiocardiopathy in clinic in China, but its application in liver diseases remains unclear. Our study aims to investigate the effect of Salvianolate on rat hepatic injury by protecting hepatocyte mitochondria. To evaluate the effects of Salvianolate on injured hepatocytes, alpha mouse liver 12 (AML-12) cells were induced with hydrogen peroxide (H2O2) and treated with Salvianolate. Cell viability and MitoTracker Green for mitochondria and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazole-carbocyanide iodine (JC-1) levels and cytochrome C (Cyto-C) expressions were detected in vitro. To identify the effect of Salvianolate on protecting against mitochondria injury, male Wistar rats were injected with carbon tetrachloride (CCl4) and treated with Salvianolate (40 mg·kg−1). Serum liver function, parameters for peroxidative damage, hematoxylin and eosin (H&E) staining, and transmission electron microscope (TEM) of hepatocyte mitochondria were assayed. Our results showed that Salvianolate effectively protected hepatocytes, increased mitochondria vitality, and decreased Cyto-C expressions in vitro. Besides, Salvianolate alleviated the liver function, attenuated the indicators of peroxidation, and relieved the mitochondria injury in vivo. In conclusion, Salvianolate is effective in protecting hepatocytes from injury in vitro and in vivo, and the mechanism might be related to its protective effect on hepatocyte mitochondria against oxidative stress. PMID:27340417

  12. Biomechanics and functionality of hepatocytes in liver cirrhosis.

    PubMed

    Sun, Shan; Song, Zhenyuan; Cotler, Scott J; Cho, Michael

    2014-06-27

    Cirrhosis is a life-threatening condition that is generally attributed to overproduction of collagen fibers in the extracellular matrix that mechanically stiffens the liver. Chronic liver injury due to causes including viral hepatitis, inherited and metabolic liver diseases and external factors such as alcohol abuse can result in the development of cirrhosis. Progression of cirrhosis leads to hepatocellular dysfunction. While extensive studies to understand the complexity underlying liver fibrosis have led to potential application of anti-fibrotic drugs, no such FDA-approved drugs are currently available. Additional studies of hepatic fibrogenesis and cirrhosis primarily have focused on the extracellular matrix, while hepatocyte biomechanics has received limited attention. The role of hepatocyte biomechanics in liver cirrhosis remains elusive, and how the cell stiffness is correlated with biological functions of hepatocytes is also unknown. In this study, we demonstrate that the biomechanical properties of hepatocytes are correlated with their functions (e.g., glucose metabolism), and that hepatic dysfunction can be restored through modulation of the cellular biomechanics. Furthermore, our results indicate the hepatocyte functionality appears to be regulated through a crosstalk between the Rho and Akt signaling. These novel findings may lead to biomechanical intervention of hepatocytes and the development of innovative tissue engineering for clinical treatment to target liver cells rather than exclusively focusing on the extracellular matrix alone in liver cirrhosis.

  13. Hepatocyte apoptosis in dairy cattle during the transition period.

    PubMed

    Tharwat, Mohamed; Takamizawa, Aya; Hosaka, Yoshinao Z; Endoh, Daiji; Oikawa, Shin

    2012-10-01

    The objective of this study was to investigate hepatocyte apoptosis in dairy cows during the transition period. Four clinically healthy, pregnant dairy cattle were used. The cows had no clinical diseases throughout this study. Blood samples were collected and livers were biopsied from the cows at 3 different times: 3 weeks before expected partition (wk -3); during parturition (wk 0), and 3 weeks (wk +3) after parturition. The damage to deoxyribonucleic acid (DNA) caused by hepatocytes was evaluated by comet assay. The apoptotic features of hepatocytes were examined by immunohistochemistry and electron microscopic analyses. The hepatic triglyceride content markedly increased at wk 0 and wk +3 compared with the values at wk -3. The results of the comet assay showed increases in the mean tail moment values of hepatic cells after parturition in all cows, which suggested increased DNA damage. Histopathologically, the hepatocytes began to contain lipid droplets at wk 0 and were severely opacified at wk +3. Caspase-3-positive and single-stranded DNA-(ssDNA)-positive cells were first detected in the liver after parturition. Condensation of nuclear chromatin, a typical sign of apoptosis, was confirmed by transmission electron microscopy after parturition. These results suggest that apoptosis is induced in hepatocytes of dairy cows around parturition and may result from lipotoxicity in hepatocytes.

  14. cAMP prevents TNF-induced apoptosis through inhibiting DISC complex formation in rat hepatocytes.

    PubMed

    Bhattacharjee, Rajesh; Xiang, Wenpei; Wang, Yinna; Zhang, Xiaoying; Billiar, Timothy R

    2012-06-22

    Tumor necrosis factor α (TNF) is a pleiotropic proinflammatory cytokine that plays a role in immunity and the control of cell proliferation, cell differentiation, and apoptosis. The pleiotropic nature of TNF is due to the formation of different signaling complexes upon the binding of TNF to its receptor, TNF receptor type 1 (TNFR1). TNF induces apoptosis in various mammalian cells when the cells are co-treated with a transcription inhibitor like actinomycin D (ActD). When TNFR1 is activated, it recruits an adaptor protein, TNF receptor-associated protein with death domain (TRADD), through its cytoplasmic death effector domain (DED). TRADD, in turn, recruits other signaling proteins, including TNF receptor-associated protein 2 (TRAF2) and receptor-associated protein kinase (RIPK) 1, to form a complex. Subsequently, this complex combines with FADD and procaspase-8, converts into a death-inducing signaling complex (DISC) to induce apoptosis. Cyclic AMP (cAMP) is a second messenger that regulates various cellular processes such as cell proliferation, gene expression, and apoptosis. cAMP analogues are reported to act as anti-apoptotic agents in various cell types, including hepatocytes. We found that a cAMP analogue, dibutyryl cAMP (db-cAMP), inhibits TNF+ActD-induced apoptosis in rat hepatocytes. The protein kinase A (PKA) inhibitor KT-5720 reverses this inhibitory effect of cAMP on apoptosis. Cytoprotection by cAMP involves down-regulation of various apoptotic signal regulators like TRADD and FADD and inhibition of caspase-8 and caspase-3 cleavage. We also found that cAMP exerts its affect at the proximal level of TNF signaling by inhibiting the formation of the DISC complex upon the binding of TNF to TNFR1. In conclusion, our study shows that cAMP prevents TNF+ActD-induced apoptosis in rat hepatocytes by inhibiting DISC complex formation.

  15. Potassium transmembrane fluxes in anoxic hepatocytes from goldfish (Carassius auratus L.).

    PubMed

    Mut, P N; Espelt, M V; Krumschnabel, G; Schwarzbaum, P J

    2006-01-01

    Despite the fact that anoxic goldfish hepatocytes can maintain the transmembrane gradients of Na(+), H(+) and Ca(2+), cyanide (CN) intoxication leads to a rapid breakdown of K(+) homeostasis. In this study, [(86)Rb(+)] K(+) fluxes across the plasma membrane of goldfish hepatocytes were studied in order to identify the possible causes of this imbalance. Four minutes of cyanide incubation induced an acute and stable 61% decrease of K(+) influx (mostly driven by Na,K-ATPase activity), whereas K(+) efflux increased by 24.3%, this imbalance yielding a net K(+) efflux of 0.279+/-0.024 nmol 10(-6) cells(-1) min(-1). This uncoupling was not observed when glycolytic ATP production was inhibited with iodoacetic acid. Although the CN-induced decrease of K(+) influx was fully reversible upon washout of the inhibitor, it could not be prevented by any of the following treatments: (1) addition of 2% bovine serum albumin, which binds extracellular fatty acids known to activate specific K(+) channels; (2) addition of ascorbate, which acts as a radical scavenger; (3) inclusion of 5 mM glucose as an extracellular carbon source; and (4) removal of medium oxygen (obtained by nitrogen bubbling). Regarding the elevation of K(+) efflux in the presence of CN, neither ATP-dependent K(+) channels nor the KCl cotransporter appeared to be activated, whereas BaCl(2), an inhibitor of voltage-gated K(+) channels, decreased K(+) efflux of CN-intoxicated cells to control levels. In summary, these results indicate that, in goldfish hepatocytes, the CN-induced K(+) imbalance results from acute Na,K-ATPase inhibition together with the activation of voltage-dependent K(+) channels, the latter probably resulting from transient membrane depolarization.

  16. Perinatal deiodinase 2 expression in hepatocytes defines epigenetic susceptibility to liver steatosis and obesity

    PubMed Central

    Fonseca, Tatiana L.; Fernandes, Gustavo W.; McAninch, Elizabeth A.; Bocco, Barbara M. L. C.; Abdalla, Sherine M.; Ribeiro, Miriam O.; Mohácsik, Petra; Fekete, Csaba; Li, Daofeng; Xing, Xiaoyun; Wang, Ting; Gereben, Balázs; Bianco, Antonio C.

    2015-01-01

    Thyroid hormone binds to nuclear receptors and regulates gene transcription. Here we report that in mice, at around the first day of life, there is a transient surge in hepatocyte type 2 deiodinase (D2) that activates the prohormone thyroxine to the active hormone triiodothyronine, modifying the expression of ∼165 genes involved in broad aspects of hepatocyte function, including lipid metabolism. Hepatocyte-specific D2 inactivation (ALB-D2KO) is followed by a delay in neonatal expression of key lipid-related genes and a persistent reduction in peroxisome proliferator-activated receptor-γ expression. Notably, the absence of a neonatal D2 peak significantly modifies the baseline and long-term hepatic transcriptional response to a high-fat diet (HFD). Overall, changes in the expression of approximately 400 genes represent the HFD response in control animals toward the synthesis of fatty acids and triglycerides, whereas in ALB-D2KO animals, the response is limited to a very different set of only approximately 200 genes associated with reverse cholesterol transport and lipase activity. A whole genome methylation profile coupled to multiple analytical platforms indicate that 10–20% of these differences can be related to the presence of differentially methylated local regions mapped to sites of active/suppressed chromatin, thus qualifying as epigenetic modifications occurring as a result of neonatal D2 inactivation. The resulting phenotype of the adult ALB-D2KO mouse is dramatic, with greatly reduced susceptibility to diet-induced steatosis, hypertriglyceridemia, and obesity. PMID:26508642

  17. Induction of hepatocyte proliferation by retinoic acid.

    PubMed

    Ledda-Columbano, G M; Pibiri, M; Molotzu, F; Cossu, C; Sanna, L; Simbula, G; Perra, A; Columbano, A

    2004-11-01

    Retinoids have been shown to exert an anticarcinogenic effect through suppression of the cell cycle, induction of apoptosis and/or differentiation. In rat liver, in particular, retinoic acid has been shown to inhibit regeneration after partial hepatectomy, most probably through repression of the expression of c-fos and c-jun. Surprisingly enough, in spite of the proposed therapeutic effects of all-trans retinoic acid (tRA) no data are available on its effect on normal adult liver. Here, we show that tRA administration in the diet (150 mg/kg) increased DNA synthesis in mouse liver, at 1 and 2 weeks, with a return to control values at 4 weeks (labelling index was 16.5, 8.3 and 3.3%, respectively, versus control values of 1.4, 1.3 and 2.5%). Increase in mitotic index paralleled that of bromodeoxyuridine incorporation. Kinetic studies showed that entry into S phase began between 24 and 48 h, with a peak between 96 and 120 h. Histological observation of the liver and biochemical evaluation of the levels of serum glutamate-pyruvate transaminases did not reveal any evidence of cell death demonstrating that increased DNA synthesis was not due to tRA-induced liver damage and regeneration, but rather the consequence of a direct mitogenic effect. In addition, analysis of total hepatic DNA content after a 7-day treatment showed a significant increase in tRA-fed mice compared with controls (21.11 mg/100 g body wt in tRA-fed mice versus 15.67 mg/100 g body wt of controls). Hepatocyte proliferation in tRA-fed mice was associated with increased hepatic levels of cyclin D1, E and A, and enhanced expression of the member of pRb family, p107. In conclusion, the results showed that tRA induces hepatocyte proliferation in the absence of cell death, similarly to other ligands of steroid/thyroid hormone nuclear receptor superfamily. The mitogenic effect of tRA cautions about its possible use for antitumoral purposes in liver carcinogenesis.

  18. MicroRNA-96 promotes myocardial hypertrophy by targeting mTOR.

    PubMed

    Sun, Xuemei; Zhang, Chunlai

    2015-01-01

    As a main cause of cardiac hypertrophy, myocardial hypertrophy includes the proliferation and enlongation of myocardial cell, resulting in abnormally cardiac enlargement. However, the pathogenesis and the molecular mechanism that regulate gene expression of myocardial hypertrophy remain incompletely understood. MiRNAs were deemed as an important molecules involved in a variety of pathological processes. MiR-96 has been reported being associated with the tumor proliferation, but whether miR-96 is involved in cardiac hypertrophy remains uncertain. In this study, we have confirmed that, as the myocardial hypertrophy gene, mTOR was a target gene of miR-96, who would promote the occurrence of myocardial hypertrophy. Thus, we got the conclusion that miR-96 could promote myocardial hypertrophy by inhibiting mTOR, miR-96 and mTOR were negatively correlated.

  19. Klotho gene delivery ameliorates renal hypertrophy and fibrosis in streptozotocin-induced diabetic rats by suppressing the Rho-associated coiled-coil kinase signaling pathway.

    PubMed

    Deng, Minghong; Luo, Yumei; Li, Yunkui; Yang, Qiuchen; Deng, Xiaoqin; Wu, Ping; Ma, Houxun

    2015-07-01

    The present study aimed to investigate whether klotho gene delivery attenuated renal hypertrophy and fibrosis in streptozotocin-induced diabetic rats. A recombinant adeno-associated virus (rAAV) carrying mouse klotho full-length cDNA (rAAV.mKL), was constructed for in vivo investigation of klotho expression. Diabetes was induced in rats by a single tail vein injection of 60 mg/kg streptozotocin. Subsequently, the diabetic rats received an intravenous injection of rAAV.mKL, rAAV.green fluorescent protein (GFP) or phosphate-buffered saline (PBS). The Sprague-Dawley rat group received PBS and served as the control group. After 12 weeks, all the rats were sacrificed and ELISA, immunohistochemical and histological analyses, fluorescence microscopy, semi-quantitative reverse transcription-polymerase chain reaction and western blottin were performed. A single dose of rAAV.mKL was found to prevent the progression of renal hypertrophy and fibrosis for at least 12 weeks (duration of study). Klotho expression was suppressed in the diabetic rats, but was increased by rAAV.mKL delivery. rAAV.mKL significantly suppressed diabetes-induced renal hypertrophy and histopathological changes, reduced renal collagen fiber generation and decreased kidney hypertrophy index. In addition, rAAV.mKL decreased the protein expression levels of fibronectin and vimentin, while it downregulated the mRNA expression and activity of Rho-associated coiled-coil kinase (ROCK)I in the kidneys of the diabetic rats. These results indicated that klotho gene delivery ameliorated renal hypertrophy and fibrosis in diabetic rats, possibly by suppressing the ROCK signaling pathway. This may offer a novel approach for the long-term control and renoprotection of diabetes.

  20. DIOL Triterpenes Block Profibrotic Effects of Angiotensin II and Protect from Cardiac Hypertrophy

    PubMed Central

    Jurado-López, Raquel; Martínez-Martínez, Ernesto; Gómez-Hurtado, Nieves; Delgado, Carmen; Visitación Bartolomé, Maria; San Román, José Alberto; Cordova, Claudia; Lahera, Vicente; Nieto, Maria Luisa; Cachofeiro, Victoria

    2012-01-01

    Background The natural triterpenes, erythrodiol and uvaol, exert anti-inflammatory, vasorelaxing and anti-proliferative effects. Angiotensin II is a well-known profibrotic and proliferative agent that participates in the cardiac remodeling associated with different pathological situations through the stimulation and proliferation of cardiac fibroblasts. Therefore, the aim of the study was to investigate the preventive effects of the natural triterpenes erythrodiol and uvaol on the proliferation and collagen production induced by angiotensin II in cardiac myofibroblasts. Their actions on cardiac hypertrophy triggered by angiotensin II were also studied. Methodology/Principal Findings The effect of erythrodiol and uvaol on angiotensin II-induced proliferation was evaluated in cardiac myofibroblasts from adult rats in the presence or the absence of the inhibitors of PPAR-γ, GW9662 or JNK, SP600125. The effect on collagen levels induced by angiotensin II was evaluated in cardiac myofibroblasts and mouse heart. The presence of low doses of both triterpenes reduced the proliferation of cardiac myofibroblasts induced by angiotensin II. Pretreatment with GW9662 reversed the effect elicited by both triterpenes while SP600125 did not modify it. Both triterpenes at high doses produced an increase in annexing-V binding in the presence or absence of angiotensin II, which was reduced by either SP600125 or GW9662. Erythrodiol and uvaol decreased collagen I and galectin 3 levels induced by angiotensin II in cardiac myofribroblasts. Finally, cardiac hypertrophy, ventricular remodeling, fibrosis, and increases in myocyte area and brain natriuretic peptide levels observed in angiotensin II-infused mice were reduced in triterpene-treated animals. Conclusions/Significance Erythrodiol and uvaol reduce cardiac hypertrophy and left ventricle remodeling induced by angiotensin II in mice by diminishing fibrosis and myocyte area. They also modulate growth and survival of cardiac

  1. Nonalcoholic Lipid Accumulation and Hepatocyte Malignant Transformation

    PubMed Central

    Gu, Juanjuan; Yao, Min; Yao, Dengbing; Wang, Li; Yang, Xuli; Yao, Dengfu

    2016-01-01

    Abstract Worldwide incidence of hepatocellular carcinoma (HCC) is steadily increasing, highlighting its status as a public health concern, particularly due to its significant association with other comorbidities, such as diabetes. However, nonalcoholic fatty liver disease (NAFLD) has emerged as a primary risk factor, with its own prevalence increasing in recent years, and it has gradually caught up with the historical primary etiological factors of infection with hepatitis B virus and hepatitis C virus, exposure to aflatoxin, or alcohol liver disease. The deeply worrisome aspects of all of these high risk factors, however, are their remarkable presence within populations. Systemic and genetic mechanisms involved in the malignant transformation of liver cells, as well as useful biomarkers of early stage HCC are being investigated. However, the exact mechanisms underlying the interrelation of NAFLD and HCC remain largely unknown. In this review, some of the recent advances in our understanding of liver lipid accumulation are summarized and discussed to provide insights into the relationship between NAFLD and hepatocyte malignant transformation. PMID:27350942

  2. In vitro culture of isolated primary hepatocytes and stem cell-derived hepatocyte-like cells for liver regeneration.

    PubMed

    Hu, Chenxia; Li, Lanjuan

    2015-08-01

    Various liver diseases result in terminal hepatic failure, and liver transplantation, cell transplantation and artificial liver support systems are emerging as effective therapies for severe hepatic disease. However, all of these treatments are limited by organ or cell resources, so developing a sufficient number of functional hepatocytes for liver regeneration is a priority. Liver regeneration is a complex process regulated by growth factors (GFs), cytokines, transcription factors (TFs), hormones, oxidative stress products, metabolic networks, and microRNA. It is well-known that the function of isolated primary hepatocytes is hard to maintain; when cultured in vitro, these cells readily undergo dedifferentiation, causing them to lose hepatocyte function. For this reason, most studies focus on inducing stem cells, such as embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), hepatic progenitor cells (HPCs), and mesenchymal stem cells (MSCs), to differentiate into hepatocyte-like cells (HLCs) in vitro. In this review, we mainly focus on the nature of the liver regeneration process and discuss how to maintain and enhance in vitro hepatic function of isolated primary hepatocytes or stem cell-derived HLCs for liver regeneration. In this way, hepatocytes or HLCs may be applied for clinical use for the treatment of terminal liver diseases and may prolong the survival time of patients in the near future.

  3. Caffeine induces CYP1A2 expression in rat hepatocytes but not in human hepatocytes.

    PubMed

    Vaynshteyn, David; Jeong, Hyunyoung

    2012-06-01

    Caffeine is the active constituent in coffee. Continual consumption of caffeine can lead to an attenuated response also known as tolerance. Results from rat studies have shown that caffeine is an inducer of CYP1A2, the enzyme responsible for caffeine's metabolism. This suggests that CYP1A2 induction by caffeine may be in part responsible for caffeine tolerance. However, whether caffeine induces CYP1A2 expression in humans remains unknown. Our results from luciferase assays performed in HepG2 cells showed that caffeine is not an activator of the aromatic hydrocarbon receptor (AhR), a major transcription factor involved in upregulation of CYP1A2. Furthermore, caffeine did not induce CYP1A2 expression in primary human hepatocytes at a concentration attained by ordinary coffee drinking. On the other hand, caffeine enhanced CYP1A2 expression by 9-fold in rat hepatocytes. Our results suggest that caffeine from ordinary coffee drinking does not induce CYP1A2 expression in humans and that factors other than CYP1A2 induction by caffeine likely contribute to development of caffeine tolerance in humans.

  4. Differentiated properties of hepatocytes induced from pancreatic cells.

    PubMed

    Tosh, David; Shen, Chia-Ning; Slack, Jonathan M W

    2002-09-01

    Transdifferentiation of pancreas to liver is a well-recognized phenomenon and has been described in animal experiments and human pathology. We recently produced an in vitro model for the transdifferentiation (or conversion) of the pancreatic cell line AR42J-B13 to hepatocytes based on culture with dexamethasone (Dex). To determine whether the hepatocytes express markers of hepatic intermediary metabolism and detoxification, we investigated the patterns of expression of glucokinase, cytochrome P450s CYP3A1 and CYP2B1/2, testosterone/4-nitrophenol uridine diphosphate glucuronosyltransferase (UDPGT), and aryl sulfotransferase. All were expressed. We also determined the expression of 2 enzymes involved in ammonia detoxification: carbamoylphosphate synthetase I (CPS I) and glutamine synthetase (GS). These enzymes are normally strictly compartmentalized in liver in a wide periportal pattern and the last downstream perivenous hepatocytes, respectively. Following culture with Dex, CPS I and GS are expressed in 2 different cell populations, suggesting that both periportal and perivenous hepatocytes are induced. We also produced a reporter assay based on the activation of green fluorescent protein (GFP) by the transthyretin (TTR) promoter or glucose-6-phosphatase (G6Pase) promoter. After culture with Dex, transfected cells begin to express GFP, showing that hepatic promoters are activated in concert with the induction of the hepatocyte phenotype. Lastly, we examined the stability of the hepatic phenotype and found that some cells still express liver markers (transferrin or albumin) up to 14 days after removal of Dex. In conclusion, these results suggest that pancreatic hepatocytes produced by this method may offer an alternative model to primary cultures of hepatocytes for the study of liver function.

  5. Role of macrophages in the immune response to hepatocytes

    SciTech Connect

    Bumgardner, G.L.; Chen, S.; Almond, S.P.; Ascher, N.L.; Payne, W.D.; Matas, A.J. )

    1990-06-01

    The purpose of this study was to determine the role of host macrophages in the development of allospecific cytolytic T cells (allo-CTLs) in response to purified allogeneic MHC Class I+, Class II- hepatocytes in vivo in hepatocyte sponge matrix allografts (HC-SMA). Depletion of antigen-presenting cells (APCs) from responder splenocytes in mixed lymphocyte hepatocyte culture (MLHC) inhibits the development of allo-CTLs in response to purified hepatocytes. First the ability of sponge macrophages to function as accessory cells in indirect presentation of hepatocyte Class I antigen was tested in MLHC. We found that addition of irradiated sponge cells (a source of sponge macrophages) restored the development of allo-CTLs in MLHC depleted of responder APCs. Therefore, radioresistant sponge macrophages can function as accessory cells in MLHC. We next employed silica as an immunotherapy targeted against host macrophages and assessed the effect on development of allo-CTLs in HC-SMA. We found that local (intrasponge) silica treatment completely inhibited the development of allo-CTLs in HC-SMA. Combined local and systemic silica treatment resulted in inhibition of allocytotoxicity comparable to local silica treatment alone in the doses tested. We conclude that host macrophages which infiltrate HC-SMA can function as accessory cells in vitro in MLHC and that both infiltrating host macrophages and lymphocytes participate in the development of an alloimmune response to purified hepatocytes in vivo. This interaction may involve indirect antigen presentation of hepatocyte Class I antigen by macrophages to host lymphocytes which accumulate in HC-SMA.

  6. Rifampicin induction of lidocaine metabolism in cultured human hepatocytes.

    PubMed

    Li, A P; Rasmussen, A; Xu, L; Kaminski, D L

    1995-08-01

    In our laboratory, cultured human hepatocytes are being evaluated as an experimental system to study drug interactions. We report the effect of a known cytochrome P450 (CYP) inducer, rifampicin, on the metabolism of lidocaine by primary human hepatocytes. Rifampicin has been shown to induce CYP3A4, a major human hepatic CYP isozyme that is known to metabolize lidocaine to its primary metabolite, monoethylglycinexylidide. Human hepatocytes were cultured on collagen-coated plates in serum-free, hormone-supplemented Waymouth medium for a 3-day period before they were treated with rifampicin at 50 microM for 1 to 3 days. Hepatocytes isolated from five individuals were studied, and, in all cases, lidocaine metabolism was found to be induced by rifampicin, as demonstrated by a higher rate of monoethylglycinexylidide formation than concurrent controls. For three of the hepatocyte cultures, lidocaine metabolism was evaluated at various times after treatment. Induction was observed at 1 day after treatment, and reached higher levels at day 2 or 3. The level of induction was found to be approximately 100% for two hepatocyte isolations and approximately 600% for one isolation. In a separate experiment, hepatocytes were treated with rifampicin for a 2-day period. Rate of lidocaine metabolism at multiple substrate concentrations (10-120 microM) were then studied. Rifampicin induction of lidocaine metabolism (approximately 100%) was observed at all the lidocaine concentrations studied. Lineweaver-Burk plot of the data showed an increase in Vmax and a less significant change in Km. Induction of lidocaine metabolism by rifampicin (concentrations of 0.1-50 microM) was found to be dose-dependent, with significant induction observed at 1 microM and higher concentrations. (ABSTRACT TRUNCATED AT 250 WORDS)

  7. Prevention of anemia alleviates heart hypertrophy in copper deficient rats

    SciTech Connect

    Lure, M.D.; Fields, M.; Lewis, C.G. Univ. of Maryland, College Park Georgetown Univ., Washington, DC )

    1991-03-11

    The present investigation was designed to examine the role of anemia in the cardiomegaly and myocardial pathology of copper deficiency. Weanling rats were fed a copper deficient diet containing either starch (ST) or fructose (FRU) for five weeks. Six rats consuming the FRU diet were intraperitoneally injected once a week with 1.0 ml/100g bw of packed red blood cells (RBC) obtained from copper deficient rats fed ST. FRU rats injected with RBC did not develop anemia. Additionally, none of the injected rats exhibited heart hypertrophy or gross pathology and all survived. In contrast, non-injected FRU rats were anemic, exhibited severe signs of copper deficiency which include heart hypertrophy with gross pathology, and 44% died. Maintaining the hematocrit with RBC injections resulted in normal heart histology and prevented the mortality associated with the fructose x copper interaction. The finding suggest that the anemia associated with copper deficiency contributes to heart pathology.

  8. cAMP prevents TNF-induced apoptosis through inhibiting DISC complex formation in rat hepatocytes

    SciTech Connect

    Bhattacharjee, Rajesh; Xiang, Wenpei; Wang, Yinna; Zhang, Xiaoying

    2012-06-22

    Highlights: Black-Right-Pointing-Pointer cAMP blocks cell death induced by TNF and actinomycin D in cultured hepatocytes. Black-Right-Pointing-Pointer cAMP blocks NF-{kappa}B activation induced by TNF and actinomycin D. Black-Right-Pointing-Pointer cAMP blocks DISC formation following TNF and actinomycin D exposure. Black-Right-Pointing-Pointer cAMP blocks TNF signaling at a proximal step. -- Abstract: Tumor necrosis factor {alpha} (TNF) is a pleiotropic proinflammatory cytokine that plays a role in immunity and the control of cell proliferation, cell differentiation, and apoptosis. The pleiotropic nature of TNF is due to the formation of different signaling complexes upon the binding of TNF to its receptor, TNF receptor type 1 (TNFR1). TNF induces apoptosis in various mammalian cells when the cells are co-treated with a transcription inhibitor like actinomycin D (ActD). When TNFR1 is activated, it recruits an adaptor protein, TNF receptor-associated protein with death domain (TRADD), through its cytoplasmic death effector domain (DED). TRADD, in turn, recruits other signaling proteins, including TNF receptor-associated protein 2 (TRAF2) and receptor-associated protein kinase (RIPK) 1, to form a complex. Subsequently, this complex combines with FADD and procaspase-8, converts into a death-inducing signaling complex (DISC) to induce apoptosis. Cyclic AMP (cAMP) is a second messenger that regulates various cellular processes such as cell proliferation, gene expression, and apoptosis. cAMP analogues are reported to act as anti-apoptotic agents in various cell types, including hepatocytes. We found that a cAMP analogue, dibutyryl cAMP (db-cAMP), inhibits TNF + ActD-induced apoptosis in rat hepatocytes. The protein kinase A (PKA) inhibitor KT-5720 reverses this inhibitory effect of cAMP on apoptosis. Cytoprotection by cAMP involves down-regulation of various apoptotic signal regulators like TRADD and FADD and inhibition of caspase-8 and caspase-3 cleavage. We also found

  9. Role of microtubules in the contractile dysfunction of hypertrophied myocardium

    NASA Technical Reports Server (NTRS)

    Zile, M. R.; Koide, M.; Sato, H.; Ishiguro, Y.; Conrad, C. H.; Buckley, J. M.; Morgan, J. P.; Cooper, G. 4th

    1999-01-01

    OBJECTIVES: We sought to determine whether the ameliorative effects of microtubule depolymerization on cellular contractile dysfunction in pressure overload cardiac hypertrophy apply at the tissue level. BACKGROUND: A selective and persistent increase in microtubule density causes decreased contractile function of cardiocytes from cats with hypertrophy produced by chronic right ventricular (RV) pressure overloading. Microtubule depolymerization by colchicine normalizes contractility in these isolated cardiocytes. However, whether these changes in cellular function might contribute to changes in function at the more highly integrated and complex cardiac tissue level was unknown. METHODS: Accordingly, RV papillary muscles were isolated from 25 cats with RV pressure overload hypertrophy induced by pulmonary artery banding (PAB) for 4 weeks and 25 control cats. Contractile state was measured using physiologically sequenced contractions before and 90 min after treatment with 10(-5) mol/liter colchicine. RESULTS: The PAB significantly increased RV systolic pressure and the RV weight/body weight ratio in PAB; it significantly decreased developed tension from 59+/-3 mN/mm2 in control to 25+/-4 mN/mm2 in PAB, shortening extent from 0.21+/-0.01 muscle lengths (ML) in control to 0.12+/-0.01 ML in PAB, and shortening rate from 1.12+/-0.07 ML/s in control to 0.55+/-0.03 ML/s in PAB. Indirect immunofluorescence confocal microscopy showed that PAB muscles had a selective increase in microtubule density and that colchicine caused complete microtubule depolymerization in both control and PAB papillary muscles. Microtubule depolymerization normalized myocardial contractility in papillary muscles of PAB cats but did not alter contractility in control muscles. CONCLUSIONS: Excess microtubule density, therefore, is equally important to both cellular and to myocardial contractile dysfunction caused by chronic, severe pressure-overload cardiac hypertrophy.

  10. Integrin binding angiopoietin-1 monomers reduce cardiac hypertrophy

    PubMed Central

    Dallabrida, Susan M.; Ismail, Nesreen S.; Pravda, Elke A.; Parodi, Emily M.; Dickie, Renee; Durand, Ellen M.; Lai, Jean; Cassiola, Flavia; Rogers, Rick A.; Rupnick, Maria A.

    2008-01-01

    Angiopoietins were thought to be endothelial cell-specific via the tie2 receptor. We showed that angiopoietin-1 (ang1) also interacts with integrins on cardiac myocytes (CMs) to increase survival. Because ang1 monomers bind and activate integrins (not tie2), we determined their function in vivo. We examined monomer and multimer expressions during physiological and pathological cardiac remodeling and overexpressed ang1 monomers in phenylephrine-induced cardiac hypertrophy. Cardiac ang1 levels (mRNA, protein) increased during postnatal development and decreased with phenylephrine-induced cardiac hypertrophy, whereas tie2 phosphorylations were unchanged. We found that most or all of the changes during cardiac remodeling were in monomers, offering an explanation for unchanged tie2 activity. Heart tissue contains abundant ang1 monomers and few multimers (Western blotting). We generated plasmids that produce ang1 monomers (ang1–256), injected them into mice, and confirmed cardiac expression (immunohistochemistry, RT-PCR). Ang1 monomers localize to CMs, smooth muscle cells, and endothelial cells. In phenylephrine-induced cardiac hypertrophy, ang1–256 reduced left ventricle (LV)/tibia ratios, fetal gene expressions (atrial and brain natriuretic peptides, skeletal actin, β-myosin heavy chain), and fibrosis (collagen III), and increased LV prosurvival signaling (akt, MAPKp42/44), and AMPKT172. However, tie2 phosphorylations were unchanged. Ang1–256 increased integrin-linked kinase, a key regulator of integrin signaling and cardiac health. Collectively, these results suggest a role for ang1 monomers in cardiac remodeling.—Dallabrida, S. M., Ismail, N. S., Pravda, E. A., Parodi, E. M., Dickie, R., Durand, E. M., Lai, J., Cassiola, F., Rogers, R. A., Rupnick, M. A. Integrin binding angiopoietin-1 monomers reduce cardiac hypertrophy. PMID:18502941

  11. Elucidation of MRAS-mediated Noonan syndrome with cardiac hypertrophy

    PubMed Central

    Higgins, Erin M.; Bos, J. Martijn; Tester, David J.; Ackerman, Jaeger P.; Sol-Church, Katia; Urrutia, Raul; Ackerman, Michael J.

    2017-01-01

    Noonan syndrome (NS; MIM 163950) is an autosomal dominant disorder and a member of a family of developmental disorders termed “RASopathies,” which are caused mainly by gain-of-function mutations in genes encoding RAS/MAPK signaling pathway proteins. Whole exome sequencing (WES) and trio-based genomic triangulation of a 15-year-old female with a clinical diagnosis of NS and concomitant cardiac hypertrophy and her unaffected parents identified a de novo variant in MRAS-encoded RAS-related protein 3 as the cause of her disease. Mutation analysis using in silico mutation prediction tools and molecular dynamics simulations predicted the identified variant, p.Gly23Val-MRAS, to be damaging to normal protein function and adversely affect effector interaction regions and the GTP-binding site. Subsequent ectopic expression experiments revealed a 40-fold increase in MRAS activation for p.Gly23Val-MRAS compared with WT-MRAS. Additional biochemical assays demonstrated enhanced activation of both RAS/MAPK pathway signaling and downstream gene expression in cells expressing p.Gly23Val-MRAS. Mutational analysis of MRAS in a cohort of 109 unrelated patients with phenotype-positive/genotype-negative NS and cardiac hypertrophy yielded another patient with a sporadic de novo MRAS variant (p.Thr68Ile, c.203C>T). Herein, we describe the discovery of mutations in MRAS in patients with NS and cardiac hypertrophy, establishing MRAS as the newest NS with cardiac hypertrophy-susceptibility gene. PMID:28289718

  12. Therapeutic effects of udenafil on pressure-overload cardiac hypertrophy.

    PubMed

    Kim, Hack-Lyoung; Kim, Yong-Jin; Kim, Kyung-Hee; Lee, Seung-Pyo; Kim, Hyung-Kwan; Sohn, Dae-Won; Oh, Byung-Hee; Park, Young-Bae

    2015-09-01

    This study was performed to determine whether the newly developed phosphodiesterase type 5 (PDE5) inhibitor udenafil had beneficial effects on pressure-overload cardiac hypertrophy. Pressure overload cardiac hypertrophy was created by using suprarenal aortic constriction (SAC) in male Sprague-Dawley rats. Rats were divided into three groups: sham (n=19), SAC (n=18) and SAC+udenafil (n=14) groups. Three-week periods of SAC provoked significant left ventricular (LV) hypertrophy. Udenafil was administered (20 mg kg(-1) PO, daily) between the 3rd and 20th weeks after SAC in the SAC+udenafil group. Udenafil improved the survival rate (log-rank P=0.012) and exercise capacity (maximal exercise duration at the 20th week after surgery: 448±54 s for the SAC+udenafil group versus 317±73 s for the SAC group, P<0.05) of the rats with SAC. Serial echocardiographic examinations showed that udenafil attenuated LV remodeling processes following SAC (mean LV end-diastolic dimension at the 20th week after surgery: 9.84±0.59 mm for SAC and 9.05±0.58 mm for SAC+udenafil group, P<0.05). Invasive hemodynamic studies showed that udenafil improved the LV performance. Udenafil-attenuated myocardial fibrosis and apoptosis. Udenafil also decreased myocardial matrix metalloproteinase-9 expression and augmented serum interleukin-10 concentration. Long-term udenafil use prevented cardiac remodeling and improved exercise capacity and survival in rats exposed to pressure-overload cardiac hypertrophy.

  13. The Akt-mTOR axis is a pivotal regulator of eccentric hypertrophy during volume overload

    PubMed Central

    Ikeda, Masataka; Ide, Tomomi; Fujino, Takeo; Matsuo, Yuka; Arai, Shinobu; Saku, Keita; Kakino, Takamori; Oga, Yasuhiro; Nishizaki, Akiko; Sunagawa, Kenji

    2015-01-01

    The heart has two major modalities of hypertrophy in response to hemodynamic loads: concentric and eccentric hypertrophy caused by pressure and volume overload (VO), respectively. However, the molecular mechanism of eccentric hypertrophy remains poorly understood. Here we demonstrate that the Akt-mammalian target of rapamycin (mTOR) axis is a pivotal regulator of eccentric hypertrophy during VO. While mTOR in the heart was activated in a left ventricular end-diastolic pressure (LVEDP)-dependent manner, mTOR inhibition suppressed eccentric hypertrophy and induced cardiac atrophy even under VO. Notably, Akt was ubiquitinated and phosphorylated in response to VO, and blocking the recruitment of Akt to the membrane completely abolished mTOR activation. Various growth factors were upregulated during VO, suggesting that these might be involved in Akt-mTOR activation. Furthermore, the rate of eccentric hypertrophy progression was proportional to mTOR activity, which allowed accurate estimation of eccentric hypertrophy by time-integration of mTOR activity. These results suggested that the Akt-mTOR axis plays a pivotal role in eccentric hypertrophy, and mTOR activity quantitatively determines the rate of eccentric hypertrophy progression. As eccentric hypertrophy is an inherent system of the heart for regulating cardiac output and LVEDP, our findings provide a new mechanistic insight into the adaptive mechanism of the heart. PMID:26515499

  14. The Akt-mTOR axis is a pivotal regulator of eccentric hypertrophy during volume overload.

    PubMed

    Ikeda, Masataka; Ide, Tomomi; Fujino, Takeo; Matsuo, Yuka; Arai, Shinobu; Saku, Keita; Kakino, Takamori; Oga, Yasuhiro; Nishizaki, Akiko; Sunagawa, Kenji

    2015-10-30

    The heart has two major modalities of hypertrophy in response to hemodynamic loads: concentric and eccentric hypertrophy caused by pressure and volume overload (VO), respectively. However, the molecular mechanism of eccentric hypertrophy remains poorly understood. Here we demonstrate that the Akt-mammalian target of rapamycin (mTOR) axis is a pivotal regulator of eccentric hypertrophy during VO. While mTOR in the heart was activated in a left ventricular end-diastolic pressure (LVEDP)-dependent manner, mTOR inhibition suppressed eccentric hypertrophy and induced cardiac atrophy even under VO. Notably, Akt was ubiquitinated and phosphorylated in response to VO, and blocking the recruitment of Akt to the membrane completely abolished mTOR activation. Various growth factors were upregulated during VO, suggesting that these might be involved in Akt-mTOR activation. Furthermore, the rate of eccentric hypertrophy progression was proportional to mTOR activity, which allowed accurate estimation of eccentric hypertrophy by time-integration of mTOR activity. These results suggested that the Akt-mTOR axis plays a pivotal role in eccentric hypertrophy, and mTOR activity quantitatively determines the rate of eccentric hypertrophy progression. As eccentric hypertrophy is an inherent system of the heart for regulating cardiac output and LVEDP, our findings provide a new mechanistic insight into the adaptive mechanism of the heart.

  15. Effect of adrenergic agonists and antagonists on alanine amino transferase, fructose-1:6-bisphosphatase and glucose production in hepatocytes.

    PubMed

    Begum, N A; Datta, A G

    1992-08-18

    Using rat hepatocytes we confirmed our previous results that glucagon and beta-adrenergic agonists increased the enzyme activity of alanine aminotransferase (AAT) and propranolol abolished their effects. Only the enzyme activity was measured and other parameters like quantity of the enzyme or activation due to modification were not looked for. As in perfusion experiment phenylephrine and phenoxybenzamine (alpha-agonist and alpha-antagonist respectively) also alpha-antagonist respectively) also increased the AAT activity in isolated rat hepatocytes and propranolol reversed these effects. The additive effect of glucagon and phenoxybenzamine on AAT was also persistent in hepatocyte system. Fructose-1:6-bisphosphatase (Fru-P2-ase), another key enzyme in gluconeogenic pathway, was elevated by glucagon and other beta-adrenergic agonists both in liver perfusion and isolated hepatocyte experiments and was brought back to the normal level by propranolol. In this case also only the enzyme activity was measured and no other parameters were looked for. Unlike AAT this enzyme was not stimulated by phenylephrine or phenoxybenzamine. But AAT and Fru-P2-ase activities were increased significantly by adenylate cyclase activators like fluoride or forskolin. Thus, it appears that the regulation of fru-P2-ase by glucagon is purely a b-receptor mediated process whereas AAT activation shows a mixed type of regulation where some well known alpha-agonist and antagonists are behaving as beta-agonists. Results further indicate the presence of phosphodiesterase in hepatocyte membrane which was stimulated by glucagon and brought back to the normal level by propranolol. The different adrenergic compounds stated above, not only modified the activity of the above two enzymes but also stimulated glucose production by hepatocytes from alanine which was in turn abolished by propranolol as well as amino oxyacetate (AOA), a highly specified inhibitor of AAT. This confirm the participation of AAT in

  16. Astrocyte Hypertrophy Contributes to Aberrant Neurogenesis after Traumatic Brain Injury

    PubMed Central

    Robinson, Clark; Apgar, Christopher; Shapiro, Lee A.

    2016-01-01

    Traumatic brain injury (TBI) is a widespread epidemic with severe cognitive, affective, and behavioral consequences. TBIs typically result in a relatively rapid inflammatory and neuroinflammatory response. A major component of the neuroinflammatory response is astrocytes, a type of glial cell in the brain. Astrocytes are important in maintaining the integrity of neuronal functioning, and it is possible that astrocyte hypertrophy after TBIs might contribute to pathogenesis. The hippocampus is a unique brain region, because neurogenesis persists in adults. Accumulating evidence supports the functional importance of these newborn neurons and their associated astrocytes. Alterations to either of these cell types can influence neuronal functioning. To determine if hypertrophied astrocytes might negatively influence immature neurons in the dentate gyrus, astrocyte and newborn neurons were analyzed at 30 days following a TBI in mice. The results demonstrate a loss of radial glial-like processes extending through the granule cell layer after TBI, as well as ectopic growth and migration of immature dentate neurons. The results further show newborn neurons in close association with hypertrophied astrocytes, suggesting a role for the astrocytes in aberrant neurogenesis. Future studies are needed to determine the functional significance of these alterations to the astrocyte/immature neurons after TBI. PMID:27274873

  17. Incipient speciation driven by hypertrophied lips in Midas cichlid fishes?

    PubMed

    Machado-Schiaffino, Gonzalo; Kautt, Andreas F; Torres-Dowdall, Julian; Baumgarten, Lukas; Henning, Frederico; Meyer, Axel

    2017-01-30

    Sympatric speciation has been debated in evolutionary biology for decades. Although it has gained in acceptance recently, still only a handful of empirical examples are seen as valid (e.g. crater lake cichlids). In this study, we disentangle the role of hypertrophied lips in the repeated adaptive radiations of Nicaraguan crater lake cichlid fish. We assessed the role of disruptive selection and assortative mating during the early stages of divergence and found a functional trade-off in feeding behaviour between thick- and thin-lipped ecotypes, suggesting that this trait is a target of disruptive selection. Thick-lipped fish perform better on nonevasive prey at the cost of a poorer performance on evasive prey. Using enclosures in the wild, we found that thick-lipped fish perform significantly better in rocky than in sandy habitats. We found almost no mixed pairs during two breeding seasons and hence significant assortative mating. Genetic differentiation between ecotypes seems to be related to the time since colonization, being subtle in L. Masaya (1600 generations ago) and absent in the younger L. Apoyeque (<600 generations ago). Genome-wide differentiation between ecotypes was higher in the old source lakes than in the young crater lakes. Our results suggest that hypertrophied lips might be promoting incipient sympatric speciation through divergent selection (ecological divergence in feeding performance) and nonrandom mating (assortative mating) in the young Nicaraguan crater lakes. Nonetheless, further manipulative experiments are needed in order to confirm the role of hypertrophied lips as the main cue for assortative mating.

  18. Hypertrophy of cultured bovine aortic endothelium following irradiation

    SciTech Connect

    Rosen, E.M.; Vinter, D.W.; Goldberg, I.D.

    1989-03-01

    The vascular endothelium is a vital multifunctional tissue which covers the entire luminal surface of the circulatory system. Loss of continuity of the endothelial lining normally results in cell migration and proliferation to make up for cell loss and to ensure that exposure of the thrombogenic subendothelium to platelets and clotting factors is minimized. We showed that ionizing radiation (400-3000 cGy) causes dose-dependent cell loss from confluent monolayer cultures of bovine aortic endothelium, which cannot immediately be compensated by cell proliferation. Within 24 h, the remaining attached cells undergo substantial somatic hypertrophy (evidenced by increased protein content, cell volume, and attachment area) but remain diploid. If cell loss is not excessive, monolayer continuity is restored within several days. Although reduced protein degradation may contribute, most of the protein accumulation is due to synthesis of new protein. Unlike endothelium, irradiation of smooth muscle cultures causes neither cell loss nor increased protein synthesis. Hypertrophy of irradiated endothelial cells appears to be a consequence of a proliferative stimulus (cell loss) in a population of cells which is unable to divide. It can be modulated by replating irradiated cells at different densities. We suggest that endothelial hypertrophy is an early vascular homeostatic response before clonal proliferation of surviving cells or repopulation by cells from outside of the irradiated field can compensate for cell loss.

  19. Role of Histone Demethylases in Cardiomyocytes Induced to Hypertrophy

    PubMed Central

    Carulla, Juan; García, Jeison

    2016-01-01

    Epigenetic changes induced by histone demethylases play an important role in differentiation and pathological changes in cardiac cells. However, the role of the jumonji family of demethylases in the development of cardiac hypertrophy remains elusive. In this study, the presence of different histone demethylases in cardiac cells was evaluated after hypertrophy was induced with neurohormones. A cell line from rat cardiomyocytes was used as a biological model. The phenotypic profiles of the cells, as well as the expression of histone demethylases, were studied through immunofluorescence, transient transfection, western blot, and qRT-PCR analysis after inducing hypertrophy by angiotensin II and endothelin-1. An increase in fetal gene expression (ANP, BNP, and β-MHC) was observed in cardiomyocytes after treatment with angiotensin II and endothelin-1. A significant increase in JMJD2A expression, but not in UTX or JMJD2C expression, was observed. When JMJD2A was overexpressed in cardiomyocytes through transient transfection, the effect of neurohormones on fetal cardiac gene expression was increased. We conclude that JMJD2A plays a principal role in the regulation of fetal cardiac genes, which increase in expression during the pathological hypertrophic process. PMID:27722168

  20. Effect of prophylactic digitalization on the development of myocardial hypertrophy.

    PubMed

    Cutilletta, A F; Rudnik, M; Arcilla, R A; Straube, R

    1977-11-01

    The effect of prophylactic digitalization on the development of left ventricular hypertrophy was studied in adult rats. Digitoxin, 0.1 mg/100 g body wt or solvent was given daily for 1 wk prior to either aortic constriction or sham operation and was continued until the animals were killed, either 1 or 4 wk after surgery. A hemodynamic study was done in those animals killed 1 wk after surgery; hearts of all animals were examined for evidence of myocardial hypertrophy. Constriction of the ascending aorta had no significant effect on cardiac output but did reduce peak flow velocity and flow acceleration. An increase in left ventricular mass, RNA, and hydroxyproline was found in the animals with aortic constriction. Digitoxin treatment did not alter peak flow velocity or flow acceleration, but did significantly increase isovolumic (dP/dt)P-1. Digitoxin had no effect on body weight, heart weight, RNA, or hydroxyproline in either the sham-operated animals or in the animals with aortic constriction. Therefore, despite plasma digitoxin levels sufficient to affect myocardial contractility, left ventricular hypertrophy still developed after aortic constriction.

  1. Integrin signalling: the tug-of-war in heart hypertrophy.

    PubMed

    Brancaccio, Mara; Hirsch, Emilio; Notte, Antonella; Selvetella, Giulio; Lembo, Giuseppe; Tarone, Guido

    2006-06-01

    The mechanical stress imposed by hemodynamic overload on heart walls is a primary event in triggering the cardiac hypertrophic response. Integrins, a class of membrane receptors, are major players in transmitting the mechanical force across the plasma membrane and sensing the mechanical load in cardiomyocytes. In fact, integrins, together with a number of associated cytoskeletal proteins, connect the sarcomeric contractile apparatus to the extracellular matrix across the plasma membrane and trigger intracellular signaling pathways activating the cardiomyocyte hypertrophy program. In this review, we will discuss the role of the muscle-specific integrin isoform beta1D and of associated proteins such as FAK, melusin, vinculin, zyxin, VASP, and migfilin that are the most upstream elements ("initiators") activated by mechanical strain. These molecules trigger a coordinated downstream signaling cascade involving proteins such as AKT, RAS, and MAPKs that execute the biochemical program leading to cardiomyocyte hypertrophy. Better understanding of the functional role of the initiator elements is of key importance to developing novel strategies to control cardiac hypertrophy and prevent heart failure.

  2. Morphology and function of isolated hepatocytes transplanted into rat spleen.

    PubMed

    Mito, M; Ebata, H; Kusano, M; Onishi, T; Saito, T; Sakamoto, S

    1979-12-01

    Hepatocytes isolated by the collagenase digestive method were transplanted into the spleens of syngeneic rats. Morphology and function of the hepatocytes in the spleen were investigated for 12 to 17 months after transplantation. The transplanted hepatocytes proliferated and reconfigured in the spleen without direct perfusion of portal venous blood and with the presence of an intact host liver. Fourteen to 17 months after transplantation, the hepatocytes which had formed a demarcated nodule occupied approximately 40% of the area of the splenic parenchyma without undifferentiation on microscopic examination. However, the weight of the hepatized spleen did not increase beyond the weight of a normal spleen and the weight of the host liver that had normal morphology also did not differ from a normal liver. Light and electron microscopic studies demonstrated differentiated cord structure and normal architecture for each heptocyte. Furthermore, the hepatized spleen synthesized albumin and glycogen as demonstrated by immunofluorescence and histochemical studies. Ammonia tolerance and indocyanine green clearance tests revealed functioning hepatocytes in the spleen proper. These results indicate that our experimental model lends itself well to investigations in cell growth mechanism and that hepatocellular transplantation has potential clinical application to compensate for impaired hepatic function.

  3. Hepatocytes in collagen sandwich: evidence for transcriptional and translational regulation

    PubMed Central

    1992-01-01

    The influence of extracellular matrix configuration on the tissue- specific function of cultured hepatocytes was investigated. Adult rat hepatocytes sandwiched between two layers of collagen gel were compared to cells cultured on a single layer of collagen gel for differences in the total RNA content, the level of albumin-specific mRNA, the rate of albumin gene transcription, and the rate of albumin mRNA translation. Adult hepatocytes in the sandwich system maintained the level of albumin mRNA similar to that found in the normal liver for at least six weeks, whereas the level of albumin mRNA declined rapidly in the single gel system. After one week of culture, hepatocytes in the single gel system could be induced to recover the high level of albumin mRNA and albumin production when a second layer of collagen gel was overlaid at that time. Furthermore, sandwiched hepatocytes maintained significantly higher transcriptional activity compared to cells in the single gel system. In addition to transcriptional control, the ultimate rate of albumin production was shown to depend on the rate of translation, which increased with culture time and reached a plateau in one to two weeks. This increase in translational activity over time in culture was observed in both the sandwich and the single gel systems and, thus, appeared to be independent of the configuration of extracellular matrix. PMID:1734019

  4. Molecular cytotoxic mechanisms of chlorpromazine in isolated rat hepatocytes.

    PubMed

    MacAllister, Stephanie L; Young, Cheryl; Guzdek, Anna; Zhidkov, Nickholas; O'Brien, Peter J

    2013-01-01

    Chlorpromazine (CPZ), a member of the largest class of first-generation antipsychotic agents, is known to cause hepatotoxicity in the form of cholestasis and hepatocellular necrosis in some patients. The mechanism of CPZ hepatotoxicity is unclear, but is thought to result from reactive metabolite formation. The goal of this research was to assess potential cytotoxic mechanisms of CPZ using the accelerated cytotoxicity mechanism screening (ACMS) technique with freshly isolated rat hepatocytes. This study identified CPZ cytotoxicity and inhibition of mitochondrial membrane potential (MMP) to be concentration-dependent. Furthermore, inhibition of cytochrome P450s (CYPs), including CYP2D1 and 1A2, delayed CPZ cytotoxicity, suggesting a role for CYP activation of CPZ to a toxic metabolite(s) in this model. Metabolism studies also demonstrated glucuronide and glutathione (GSH) requirement for CPZ detoxification in hepatocytes. Inactivating the 2-electron reduction pathway, NAD(P)H quinone oxidoreductase (NQO1), caused a significant increase in hepatocyte susceptibility to CPZ, indicating quinoneimine contribution to CPZ cytotoxicity. Nontoxic concentrations of peroxidase/H(2)O(2) (inflammatory model) increased cytotoxicity in CPZ-treated hepatocytes and caused additional mitochondrial toxicity. Inflammation further depleted GSH and increased oxidized glutathione (GSSG) levels. Results suggest activation of CPZ to reactive metabolites by 2 pathways in hepatocytes: (i) a CYP-catalyzed quinoneimine pathway, and (ii) a peroxidase-catalyzed oxidation of CPZ to CPZ radicals.

  5. Hepatitis B antigen in hepatocytes of chronic active liver disease.

    PubMed

    Kawanishi, H

    1979-04-01

    To study the morphologic interrelation of hepatocytes with the replication of hepatitis B vius (HBV) and immunocompetent cells in chronic active liver disease(CALD), organ cultures were prepared from liver biopsy specimens. Replication of hepatitis B core antigen (HBcAg) appears to occur in the nucleus of the hepatocyte in close association with intranuclear electron-dense strands and sometimes intranucleolar matrixes (likely HBcAg genomes), and cytoplasmic maturation of the HBcAg takes place in the preautolytic condition of host hepatocytes. Immunocompetent cells became progressively autolyzed in the early period of cultures. No difference in progression of hepatocyte injury in tissues from normal subjects and from hepatitis B surface antigen (HBsAg)-positive and HBsAg-negative patients with CALD may suggest that intracellular synthesis of HBV alone is not cytopathic to host hepatocytes. This model is promising for the study of HBV replication and development, and also for testing the efficacy of new antiviral agents against the virus.

  6. Comparison of primary human hepatocytes and hepatoma cell line Hepg2 with regard to their biotransformation properties.

    PubMed

    Wilkening, Stefan; Stahl, Frank; Bader, Augustinus

    2003-08-01

    Cultures of primary hepatocytes and hepatoma cell line HepG2 are frequently used in in vitro models for human biotransformation studies. In this study, we characterized and compared the capacity of these model systems to indicate the presence of different classes of promutagens. Genotoxic sensitivity, enzyme activity, and gene expression were monitored in response to treatment with food promutagens benzo[a]pyrene, dimethylnitrosamine (DMN), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). DNA damage could be detected reliably with the comet assay in primary human hepatocytes, which were maintained in sandwich culture. All three promutagens caused DNA damage in primary cells, but in HepG2 no genotoxic effects of DMN and PhIP could be detected. We supposed that the lack of specific enzymes accounts for their inability to process these promutagens. Therefore, we quantified the expression of a broad range of genes coding for drug-metabolizing enzymes with real-time reverse transcription-polymerase chain reaction. The genes code for cytochromes p450 and, in addition, for a series of important phase II enzymes. The expression level of these genes in human hepatocytes was similar to those previously reported for human liver samples. On the other hand, expression levels in HepG2 differed significantly from that in human. Activity and expression, especially of phase I enzymes, were demonstrated to be extremely low in HepG2 cells. Up-regulation of specific genes by test substances was similar in both cell types. In conclusion, human hepatocytes are the preferred model for biotransformation in human liver, whereas HepG2 cells may be useful to study regulation of drug-metabolizing enzymes.

  7. Strategies for short-term storage of hepatocytes for repeated clinical infusions.

    PubMed

    Jorns, Carl; Gramignoli, Roberto; Saliem, Mohammed; Zemack, Helen; Mörk, Lisa-Mari; Isaksson, Bengt; Nowak, Greg; Ericzon, Bo-Göran; Strom, Stephen; Ellis, Ewa

    2014-01-01

    Hepatocyte transplantation is an upcoming treatment for patients with metabolic liver diseases. Repeated cell infusions over 1-2 days improve clinical outcome. Isolated hepatocytes are usually cold stored in preservation solutions between repeated infusions. However, during cold storage isolated hepatocytes undergo cell death. We investigated if tissue preservation and repeated isolations are better than storage of isolated hepatocytes when cold preserving human hepatocytes. Liver tissue obtained from liver surgery or organ donors was divided into two pieces. Hepatocytes were isolated by collagenase digestion. Hepatocytes were analyzed directly after isolation (fresh) or after storage for 48 h at 4°C in University of Wisconsin solution (UW cells). Liver tissue from the same donor was stored at 4°C in UW and hepatocytes were isolated after 48 h (UW tissue cells). Hepatocyte viability and function was evaluated by trypan blue exclusion, plating efficiency, ammonia metabolism, CYP 1A1/2, 2C9, 3A7, and 3A4 activities, phase II conjugation, and apoptosis evaluation by TUNEL assay and caspase-3/7 activities. Hepatocytes stored in UW showed a significantly lower viability compared to fresh cells or hepatocytes isolated from tissue stored for 48 h (54% vs. 71% vs. 79%). Plating efficiency was significantly decreased for cells stored in UW (40%) compared to fresh and UW tissue cells (63% vs. 55%). No significant differences between UW cells and UW tissue cells could be shown for CYP activities or ammonia metabolism. Hepatocytes stored in UW showed a strong increase in TUNEL-positive cells, whereas TUNEL staining in cold-stored liver tissue and hepatocytes isolated after 48 h was unchanged. This observation was confirmed by increased caspase-3/7 activities in UW cells. Although preservation of isolated hepatocytes in UW maintains function, cold storage of liver tissue and repeated hepatocyte isolations is superior to cold storage of isolated hepatocytes in preserving

  8. Chemokine Receptors, CXCR1 and CXCR2, Differentially Regulate Exosome Release in Hepatocytes

    PubMed Central

    Nojima, Hiroyuki; Konishi, Takanori; Freeman, Christopher M.; Schuster, Rebecca M.; Japtok, Lukasz; Kleuser, Burkhard; Edwards, Michael J.; Gulbins, Erich; Lentsch, Alex B.

    2016-01-01

    Exosomes are small membrane vesicles released by different cell types, including hepatocytes, that play important roles in intercellular communication. We have previously demonstrated that hepatocyte-derived exosomes contain the synthetic machinery to form sphingosine-1-phosphate (S1P) in target hepatocytes resulting in proliferation and liver regeneration after ischemia/reperfusion (I/R) injury. We also demonstrated that the chemokine receptors, CXCR1 and CXCR2, regulate liver recovery and regeneration after I/R injury. In the current study, we sought to determine if the regulatory effects of CXCR1 and CXCR2 on liver recovery and regeneration might occur via altered release of hepatocyte exosomes. We found that hepatocyte release of exosomes was dependent upon CXCR1 and CXCR2. CXCR1-deficient hepatocytes produced fewer exosomes, whereas CXCR2-deficient hepatocytes produced more exosomes compared to their wild-type controls. In CXCR2-deficient hepatocytes, there was increased activity of neutral sphingomyelinase (Nsm) and intracellular ceramide. CXCR1-deficient hepatocytes had no alterations in Nsm activity or ceramide production. Interestingly, exosomes from CXCR1-deficient hepatocytes had no effect on hepatocyte proliferation, due to a lack of neutral ceramidase and sphingosine kinase. The data demonstrate that CXCR1 and CXCR2 regulate hepatocyte exosome release. The mechanism utilized by CXCR1 remains elusive, but CXCR2 appears to modulate Nsm activity and resultant production of ceramide to control exosome release. CXCR1 is required for packaging of enzymes into exosomes that mediate their hepatocyte proliferative effect. PMID:27551720

  9. Mesenchymal Stem Cells and Cardiomyocytes Interplay to Prevent Myocardial Hypertrophy

    PubMed Central

    Tan, Xueying; Zhang, Yong; Li, Xingda; Wang, Xinyue; Zhu, Jiuxin; Wang, Yang; Yang, Fan; Wang, Baoqiu; Liu, Yanju; Xu, Chaoqian; Pan, Zhenwei; Wang, Ning; Yang, Baofeng

    2015-01-01

    Bone marrow-derived mesenchymal stem cells (BMSCs) have emerged as a promising therapeutic strategy for cardiovascular disease. However, there is no evidence so far that BMSCs can heal pathological myocardial hypertrophy. In this study, BMSCs were indirectly cocultured with neonatal rat ventricular cardiomyocytes (NRVCs) in vitro or intramyocardially transplanted into hypertrophic hearts in vivo. The results showed that isoproterenol (ISO)-induced typical hypertrophic characteristics of cardiomyocytes were prevented by BMSCs in the coculture model in vitro and after BMSC transplantation in vivo. Furthermore, activation of the Ca2+/calcineurin/nuclear factor of activated T cells cytoplasmic 3 (NFATc3) hypertrophic pathway in NRVCs was abrogated in the presence of BMSCs both in vitro and in vivo. Interestingly, inhibition of vascular endothelial growth factor (VEGF) release from BMSCs, but not basic fibroblast growth factor and insulin-like growth factor 1, abolished the protective effects of BMSCs on cardiomyocyte hypertrophy. Consistently, VEGF administration attenuated ISO-induced enlargement of cellular size; the upregulation of atrial natriuretic peptide, brain natriuretic peptide, and β-myosin heavy chain expression; and the activation of Ca2+/calcineurin/NFATc3 hypertrophic pathways, and these pathways can be abrogated by blocking VEGFR-1 in cardiomyocytes, indicating that VEGF receptor 1 is involved in the antihypertrophic role of VEGF. We further found that the ample VEGF secretion contributing to the antihypertrophic effects of BMSCs originates from the crosstalk of BMSCs and cardiac cells but not BMSCs or cardiomyocytes alone. Interplay of mesenchymal stem cells with cardiomyocytes produced synergistic effects on VEGF release. In summary, crosstalk between mesenchymal stem cells and cardiomyocytes contributes to the inhibition of myocardial hypertrophy via inhibiting Ca2+/calcineurin/NFATc3 hypertrophic pathways in cardiac cells. These results provide the

  10. The therapeutic effect of rosuvastatin on cardiac remodelling from hypertrophy to fibrosis during the end-stage hypertension in rats.

    PubMed

    Zhang, W B; Du, Q J; Li, H; Sun, A J; Qiu, Z H; Wu, C N; Zhao, G; Gong, H; Hu, K; Zou, Y Z; Ge, J B

    2012-09-01

    End-stage hypertensive heart disease is an increasing cause of cardiac mortality. Therefore, the current study focused on the cardiac remodelling from hypertrophy to fibrosis in old-aged spontaneously hypertensive rats (SHRs), and explored the therapeutic effects of Rosuvastatin and its possible mechanism(s) of action. Spontaneously hypertensive rats at age 52 weeks were randomly divided into three groups, the first two to receive Rosuvastatin at a dose of 20 mg/kg/day and 40 mg/kg/day, respectively, and the third to receive placebo, which was to be compared with Wistar-Kyoto as controls. After 2-month treatment, SBP, heart to body weight ratio (HW/BW%) and echocardiographic features were evaluated, followed by haematoxylin and eosin and Masson trichrome staining in conjunction with qPCR of foetal gene expressions. Transferase-mediated dUTP nick-end labelling assay and immunofluorescent labelling for active caspase-3 were used to detect the apoptotic cardiomyocytes. Signaling pathways involved were examined by using western blot. Old-aged SHR developed end-stage hypertensive heart disease characterized by significant enhancement of HW/BW%, LVAWd and LVPWd, and decreased LVEF and LVFS, accompanied by cardiomyocytes enlargement and fibrosis along with activation of foetal gene programme. Cardiac apoptosis increased significantly during the transition process. Rosuvastatin reduced hypertrophy significantly via AT(1) Receptor-PKCβ2/α-ERK-c-fos pathway; protected myocardium against apoptosis via Akt-FOXO1, Bcl-2 family and survivin pathways and consequently suppressed the caspase-3 activity. The present study revealed that old-aged SHRs developed cardiac remodelling from hypertrophy to fibrosis via cardiac apoptosis during the end stage of hypertensive heart disease. These pathological changes might be the consequence of activation of AT(1) Receptor-PKCβ2/α-ERK-c-fos and AKT-FOXO1/Bcl-2/survivin/Caspase3 signaling. Rosuvastatin effectively attenuated the structural

  11. The therapeutic potential of hepatocyte growth factor for myocardial infarction and heart failure.

    PubMed

    Jin, Hongkui; Wyss, J Michael; Yang, Renhui; Schwall, Ralph

    2004-01-01

    Hepatocyte growth factor (HGF) is a cytokine whose multipotent actions are mediated by c-Met receptor. This review focuses on effects of HGF on myocardial infarction (MI) and heart failure. Circulating concentrations of HGF and myocardial concentrations of HGF and c-Met mRNA and protein are substantially increased following acute MI. HGF has been shown to be cardioprotective towards acute cardiac ischemia-reperfusion injury. Gene transfection of HGF into rat hearts attenuates acute ischemia injury. Administration of HGF protein reduces infarct size and increases cardiac performance in a rat model of acute ischemia/reperfusion. In contrast, acute blockade of endogenous HGF increases infarct size and mortality. These acute effects of HGF appear to be related to angiogenic and anti-apoptotic mechanisms. Recent studies demonstrate that post-MI treatment with HGF gene or protein attenuates chronic cardiac remodeling and dysfunction. In rats, HGF gene transfer following large MI results in preserved cardiac function and geometry in association with angiogenesis and reduced apoptosis, and treatment with recombinant HGF also significantly improves cardiac performance measured 8 weeks after MI. In mice, post-MI HGF gene therapy improves cardiac remodeling and dysfunction through hypertrophy of cardiomyocytes, infarct wall thickening, preservation of vessels, and antifibrosis. In addition, gene transfer of HGF improves cardiac remodeling, angiogenesis and regional myocardial function in the chronic ischemic myocardium of dogs. Together, these preclinical data highlight the significant acute and chronic cardioprotective effects of HGF following ischemic heart failure. Clinical trials are needed to investigate the therapeutic potential of HGF for postinfarction heart failure in humans.

  12. C/EBPβ knockdown protects cardiomyocytes from hypertrophy via inhibition of p65-NFκB.

    PubMed

    Zou, Jian; Li, Hong; Chen, Xi; Zeng, Siyu; Ye, Jiantao; Zhou, Changhua; Liu, Min; Zhang, Luankun; Yu, Na; Gan, Xiaohong; Zhou, Houfeng; Xian, Zhiwei; Chen, Shaorui; Liu, Peiqing

    2014-06-05

    C/EBPβ, a member of the bHLH gene family of DNA-binding transcription factors, has been indicated as a central signal in physiologic hypertrophy. However, the role of C/EBPβ in pathological cardiac hypertrophy remains to be elucidated. In this study, we revealed that C/EBPβ is involved in cardiac hypertrophy, the expression of C/EBPβ were significantly increased in response to hypertrophic stimulation in vitro and in vivo. C/EBPβ knockdown inhibited PE-induced cardiac hypertrophy, and diminished the nuclear translocation and DNA binding activity of p65-NFκB. These results suggested that C/EBPβ knockdown protected cardiomyocytes from hypertrophy, which may be attributed to inhibition of NFκB-dependent transcriptional activity. These findings shed new light on the understanding of C/EBPβ-related cardiomyopathy, and suggest the potential application of C/EBPβ inhibitors in cardiac hypertrophy.

  13. Isolated muscle hypertrophy as a sign of radicular or peripheral nerve injury.

    PubMed Central

    Mattle, H P; Hess, C W; Ludin, H P; Mumenthaler, M

    1991-01-01

    Two patients with isolated neurogenic hypertrophy of the trapezius muscle due to accessory nerve injury and a patient with neurogenic hypertrophy of the anterior tibial muscle due to chronic radicular lesion L4 are described. Electromyography of the affected muscles showed dense continuing spontaneous discharges of complex potentials. Muscle biopsy performed in two patients showed abundant hypertrophic muscle fibres, identified in one case by ATP-ase reaction as being of predominantly type I. In the majority of previously reported patients with neurogenic muscle hypertrophy confined to the calf muscle, a passive stretch mechanism was suggested as a cause of the hypertrophy. It is assumed that the excessive spontaneous muscle activity gave rise to the hypertrophy in these patients. This may also be true in previously reported patients with neurogenic hypertrophy and similar spontaneous activity in electromyography. Images PMID:2056318

  14. miR-378 reduces mesangial hypertrophy and kidney tubular fibrosis via MAPK signalling.

    PubMed

    Wang, Bo; Yao, Kevin; Wise, Andrea F; Lau, Ricky; Shen, Hsin-Hui; Tesch, Greg H; Ricardo, Sharon D

    2017-03-01

    The regulatory role of a novel miRNA, miR-378, was determined in the development of fibrosis through repression of the MAPK1 pathway, miR-378 and fibrotic gene expression was examined in streptozotocin (STZ)-induced diabetic mice at 18 weeks or in unilateral ureteral obstruction (UUO) mice at 7 days. miR-378 transfection of proximal tubular epithelial cells, NRK52E and mesangial cells was assessed with/without endogenous miR-378 knockdown using the locked nucleic acid (LNA) inhibitor. NRK52E cells were co-transfected with the mothers against decapentaplegic homolog 3 (SMAD3) CAGA reporter and miR-378 in the presence of transforming growth factor-β (TGF-β1) was assessed. Quantitative polymerase chain reaction (qPCR) showed a significant reduction in miR-378 (P<0.05) corresponding with up-regulated type I collagen, type IV collagen and α-smooth muscle actin (SMA) in kidneys of STZ or UUO mice, compared with controls. TGF-β1 significantly increased mRNA expression of type I collagen (P<0.05), type IV collagen (P<0.05) and α-SMA (P<0.05) in NRK52E cells, which was significantly reduced (P<0.05) following miR-378 transfection and reversed following addition of the LNA inhibitor of endogenous miR-378 Overexpression of miR-378 inhibited mesangial cell expansion and proliferation in response to TGF-β1, with LNA-miR-378 transfection reversing this protective effect, associated with cell morphological alterations. The protective function of MAPK1 on miR-378 was shown in kidney cells treated with the MAPK1 inhibitor, selumetinib, which inhibited mesangial cell hypertrophy in response to TGF-β1. Taken together, these results suggest that miR-378 acts via regulation of the MAPK1 pathway. These studies demonstrate the protective function of MAPK1, regulated by miR-378, in the induction of kidney cell fibrosis and mesangial hypertrophy.

  15. Production of hepatocyte like cells from human pluripotent stem cells

    PubMed Central

    Hannan, Nicholas R.F; Segeritz, Charis-Patricia; Touboul, Thomas; Vallier, Ludovic

    2013-01-01

    Large scale production of hepatocytes from a variety of genetic backgrounds would be beneficial for drug screening and to provide a source of cells to be used as a substitute for liver transplantation. However, fully functional primary hepatocytes remain difficult to expand in vitro and circumventing this problem by using an alternative source of cells is desirable. Here, we describe a 25 day protocol to direct the differentiation of human pluripotent stem cells into a near homogenous population of hepatocyte-like cells. As cells progress through this protocol they express genes in a chronological manner similar to that described during in-vivo hepatic development. The protocol relies on culture systems devoid of serum, feeders or complex extra-cellular matrices enabling molecular analyses without interference from unknown factors. This approach works efficiently with human embryonic stem cells and human induced pluripotent stem cells and was recently used to model liver diseases in vitro. PMID:23424751

  16. Alternative Cell Sources to Adult Hepatocytes for Hepatic Cell Therapy.

    PubMed

    Pareja, Eugenia; Gómez-Lechón, María José; Tolosa, Laia

    2017-01-01

    Adult hepatocyte transplantation is limited by scarce availability of suitable donor liver tissue for hepatocyte isolation. New cell-based therapies are being developed to supplement whole-organ liver transplantation, to reduce the waiting-list mortality rate, and to obtain more sustained and significant metabolic correction. Fetal livers and unsuitable neonatal livers for organ transplantation have been proposed as potential useful sources of hepatic cells for cell therapy. However, the major challenge is to use alternative cell sources for transplantation that can be derived from reproducible methods. Different types of stem cells with hepatic differentiation potential are eligible for generating large numbers of functional hepatocytes for liver cell therapy to treat degenerative disorders, inborn hepatic metabolic diseases, and organ failure. Clinical trials are designed to fully establish the safety profile of such therapies and to define target patient groups and standardized protocols.

  17. Determination of metabolic stability using cryopreserved hepatocytes from rainbow trout (Oncorhynchus mykiss)

    EPA Science Inventory

    Standard protocols for isolating, cryopreserving, and thawing rainbow trout hepatocytes are described, along with procedures for using fresh or cryopreserved hepatocytes to assess chemical metabolic stability in fish by means of a substrate depletion approach. Variations on thes...

  18. Cryopreservation of isolated human hepatocytes for transplantation: State of the art.

    PubMed

    Terry, Claire; Dhawan, Anil; Mitry, Ragai R; Hughes, Robin D

    2006-10-01

    Hepatocytes isolated from unused donor livers are being used for transplantation in patients with acute liver failure and liver-based metabolic defects. As large numbers of hepatocytes can be prepared from a single liver and hepatocytes need to be available for emergency and repeated treatment of patients it is essential to be able to cryopreserve and store cells with good thawed cell function. This review considers the current status of cryopreservation of human hepatocytes discussing the different stages involved in the process. These include pre-treatment of cells, freezing solution, cryoprotectants and freezing and thawing protocols. There are detrimental effects of cryopreservation on hepatocyte structure and metabolic function, including cell attachment, which is important to the engraftment of transplanted cells in the liver. Cryopreserved human hepatocytes have been successfully used in clinical transplantation, with evidence of replacement of missing function. Further optimisation of hepatocyte cryopreservation protocols is important for their use in hepatocyte transplantation.

  19. Simultaneous Bilateral Hypertrophies of the Parotid Gland and Masseter Muscle: Case Report.

    PubMed

    Prabhu, Rohan; Mandel, Louis

    2017-01-01

    Increased salivary demand can lead to enlarged parotid salivary glands, and increased activity of the masseter muscles can cause masseter hypertrophy. This report describes a most unusual case of simultaneous bilateral hypertrophies of the parotid gland and masseter muscle originating from the very extensive habit of chewing gum. An extensive literature review uncovered many cases of the independent existence of masseteric or parotid hypertrophy, but no example of the simultaneous occurrence of these 2 conditions.

  20. In vivo hepatocyte MR imaging using lactose functionalized magnetoliposomes.

    PubMed

    Ketkar-Atre, Ashwini; Struys, Tom; Dresselaers, Tom; Hodenius, Michael; Mannaerts, Inge; Ni, Yicheng; Lambrichts, Ivo; Van Grunsven, Leo A; De Cuyper, Marcel; Himmelreich, Uwe

    2014-01-01

    The aim of this study was to assess a novel lactose functionalized magnetoliposomes (MLs) as an MR contrast agent to target hepatocytes as well as to evaluate the targeting ability of MLs for in vivo applications. In the present work, 17 nm sized iron oxide cores functionalized with anionic MLs bearing lactose moieties were used for targeting the asialoglycoprotein receptor (ASGP-r), which is highly expressed in hepatocytes. Non-functionalized anionic MLs were tested as negative controls. The size distribution of lactose and anionic MLs was determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS). After intravenous administration of both MLs, contrast enhancement in the liver was observed by magnetic resonance imaging (MRI). Label retention was monitored non-invasively by MRI and validated with Prussian blue staining and TEM for up to eight days post MLs administration. Although the MRI signal intensity did not show significant differences between functionalized and non-functionalized particles, iron-specific Prussian blue staining and TEM analysis confirmed the uptake of lactose MLs mainly in hepatocytes. In contrast, non-functionalized anionic MLs were mainly taken up by Kupffer and sinusoidal cells. Target specificity was further confirmed by high-resolution MR imaging of phantoms containing isolated hepatocytes, Kupffer cell (KCs) and hepatic stellate cells (HSCs) fractions. Hypointense signal was observed for hepatocytes isolated from animals which received lactose MLs but not from animals which received anionic MLs. These data demonstrate that galactose-functionalized MLs can be used as a hepatocyte targeting MR contrast agent to potentially aid in the diagnosis of hepatic diseases if the non-specific uptake by KCs is taken into account.

  1. Intrasplenic transplantation of allogeneic hepatocytes prolongs survival in anhepatic rats.

    PubMed

    Arkadopoulos, N; Lilja, H; Suh, K S; Demetriou, A A; Rozga, J

    1998-11-01

    To examine whether hepatocytes transplanted in the spleen can function as an ectopic liver, we performed hepatocyte transplantation in rats that were rendered anhepatic. Total hepatectomy was performed by using a novel single-stage technique. Following hepatectomy, Group 1 rats (n = 16) were monitored until death to determine survival time without prior intervention. Group 2 anhepatic rats (n = 20) were sacrificed at various times to measure blood hepatocyte growth factor (HGF) and transforming growth factor beta1 (TGF-beta1) levels. Group 3 (n = 16) rats received intrasplenic injection of isolated hepatocytes (2.5 x 10(7) cells/rat) followed by total hepatectomy after 3 days. Group 4 (n = 12) sham-transplanted rats received intrasplenic saline infusion, and after 3 days they were rendered anhepatic. Group 2, 3, and 4 rats were maintained on daily Cyclosporine A (10 mg/kg; intramuscularly). Group 1 anhepatic rats survived for 22.4 +/- 5.2 hours (standard deviation). The anhepatic state was associated with a progressive and statistically significant rise in blood HGF and TGF-beta1 levels. Rats that received hepatocyte transplantation before total hepatectomy had a significantly longer survival time than sham-transplanted anhepatic controls (34.1 +/- 8.5 vs. 15.5 +/- 4.8 hrs, P < .01). Additionally, at 12 hours post-hepatectomy, transplanted rats had significantly lower blood ammonia, prothrombin time, international normalized ratio, and TGF-beta1 levels when compared with sham-transplanted controls. In conclusion, intrasplenic transplantation of allogeneic hepatocytes prolonged survival, improved blood chemistry, and lowered blood TGF-beta1 levels in rats rendered anhepatic.

  2. Evidence for two Ca2(+)-mobilizing purinoceptors on rat hepatocytes.

    PubMed Central

    Dixon, C J; Woods, N M; Cuthbertson, K S; Cobbold, P H

    1990-01-01

    Aequorin measurements of cytosolic free Ca2+ in single rat hepatocytes show that ADP and ATP, thought to act through the same P2Y purinoceptor, elicited very different responses in the majority of cells tested. ADP invariably induced transients of short duration (approx. 9 s), whereas ATP induced either similar transients or transients with a much longer duration (approx. 49 s). We explain this variability in terms of two separate purinoceptors on rat hepatocytes, one of which responds to either ATP or ADP to generate free-Ca2+ transients of short duration, and the other responds to ATP only, with transients of longer duration. PMID:2386488

  3. Interspecies differences in metabolism of arsenic by cultured primary hepatocytes

    SciTech Connect

    Drobna, Zuzana; Walton, Felecia S.; Harmon, Anne W.; Thomas, David J.; Styblo, Miroslav

    2010-05-15

    Biomethylation is the major pathway for the metabolism of inorganic arsenic (iAs) in many mammalian species, including the human. However, significant interspecies differences have been reported in the rate of in vivo metabolism of iAs and in yields of iAs metabolites found in urine. Liver is considered the primary site for the methylation of iAs and arsenic (+3 oxidation state) methyltransferase (As3mt) is the key enzyme in this pathway. Thus, the As3mt-catalyzed methylation of iAs in the liver determines in part the rate and the pattern of iAs metabolism in various species. We examined kinetics and concentration-response patterns for iAs methylation by cultured primary hepatocytes derived from human, rat, mice, dog, rabbit, and rhesus monkey. Hepatocytes were exposed to [{sup 73}As]arsenite (iAs{sup III}; 0.3, 0.9, 3.0, 9.0 or 30 nmol As/mg protein) for 24 h and radiolabeled metabolites were analyzed in cells and culture media. Hepatocytes from all six species methylated iAs{sup III} to methylarsenic (MAs) and dimethylarsenic (DMAs). Notably, dog, rat and monkey hepatocytes were considerably more efficient methylators of iAs{sup III} than mouse, rabbit or human hepatocytes. The low efficiency of mouse, rabbit and human hepatocytes to methylate iAs{sup III} was associated with inhibition of DMAs production by moderate concentrations of iAs{sup III} and with retention of iAs and MAs in cells. No significant correlations were found between the rate of iAs methylation and the thioredoxin reductase activity or glutathione concentration, two factors that modulate the activity of recombinant As3mt. No associations between the rates of iAs methylation and As3mt protein structures were found for the six species examined. Immunoblot analyses indicate that the superior arsenic methylation capacities of dog, rat and monkey hepatocytes examined in this study may be associated with a higher As3mt expression. However, factors other than As3mt expression may also contribute to

  4. [Current status and future perspectives of hepatocyte transplantation].

    PubMed

    Pareja, Eugenia; Cortés, Miriam; Gómez-Lechón, M José; Maupoey, Javier; San Juan, Fernando; López, Rafael; Mir, Jose

    2014-02-01

    The imbalance between the number of potential beneficiaries and available organs, originates the search for new therapeutic alternatives, such as Hepatocyte transplantation (HT).Even though this is a treatment option for these patients, the lack of unanimity of criteria regarding indications and technique, different cryopreservation protocols, as well as the different methodology to assess the response to this therapy, highlights the need of a Consensus Conference to standardize criteria and consider future strategies to improve the technique and optimize the results.Our aim is to review and update the current state of hepatocyte transplantation, emphasizing the future research attempting to solve the problems and improve the results of this treatment.

  5. Coculture with mesenchymal stem cells results in improved viability and function of human hepatocytes.

    PubMed

    Fitzpatrick, Emer; Wu, Yue; Dhadda, Paramjeet; Hughes, Robin D; Mitry, Ragai R; Qin, Hong; Lehec, Sharon C; Heaton, Nigel D; Dhawan, Anil

    2015-01-01

    Hepatocyte transplantation is becoming an accepted therapy for acute liver failure, either as a bridge to liver regeneration or to organ transplantation. Hepatocytes provide liver function in place of the failing organ. The maintenance of sufficient viability and function of the transplanted hepatocytes is a concern. There is a lot of recent interest in mesenchymal stem cells (MSCs) for the provision of structural and trophic support to hepatocytes, but few studies currently use primary human hepatocytes. The aim of this study was to investigate if coculture of human MSCs with cryopreserved human hepatocytes may improve their function and viability, thus with potential for cellular therapy of liver disease. MSCs were isolated from human umbilical cord or adipose tissue. Hepatocytes were isolated from donor organs unsuitable for transplantation. MSCs and hepatocytes were cocultured in both direct and indirect contact. Conditioned medium (CM) from cocultured MSCs and hepatocytes was also used on hepatocytes. Viability and liver-specific function were compared between test and controls. Human hepatocytes that were cocultured directly with MSCs demonstrated improved production of albumin from day 5 to day 25 of culture. This effect was most prominent at day 15. Likewise, urea production was improved in coculture from day 5 to 25. Indirect coculture demonstrated improved albumin production by day 4 (1,107 ng/ml) versus hepatocyte monoculture (940 ng/ml). Hepatocytes in CM demonstrated a nonsignificant improvement in function. The viability of cocultured hepatocytes was superior to that of monocultured cells with up to a 16% improvement. Thus, coculture of human hepatocytes with MSCs demonstrates both improved function and viability. The effect is seen mainly with direct coculture but can also be seen in indirect culture and with CM. Such coculture conditions may convey major advantages in hepatocyte survival and function for cell transplantation.

  6. Cardiac hypertrophy induced by active Raf depends on Yorkie-mediated transcription.

    PubMed

    Yu, Lin; Daniels, Joseph P; Wu, Huihui; Wolf, Matthew J

    2015-02-03

    Organ hypertrophy can result from enlargement of individual cells or from cell proliferation or both. Activating mutations in the serine-threonine kinase Raf cause cardiac hypertrophy and contribute to Noonan syndrome in humans. Cardiac-specific expression of activated Raf also causes hypertrophy in Drosophila melanogaster. We found that Yorkie (Yki), a transcriptional coactivator in the Hippo pathway that regulates organ size, is required for Raf-induced cardiac hypertrophy in flies. Although aberrant activation of Yki orthologs stimulates cardiac hyperplasia in mice, cardiac-specific expression of an activated mutant form of Yki in fruit flies caused cardiac hypertrophy without hyperplasia. Knockdown of Yki caused cardiac dilation without loss of cardiomyocytes and prevented Raf-induced cardiac hypertrophy. In flies, Yki-induced cardiac hypertrophy required the TEA domain-containing transcription factor Scalloped, and, in mammalian cells, expression of mouse Raf(L613V), an activated form of Raf with a Noonan syndrome mutation, increased Yki-induced Scalloped activity. Furthermore, overexpression of Tgi (a Tondu domain-containing Scalloped-binding corepressor) in the fly heart abrogated Yki- or Raf-induced cardiac hypertrophy. Thus, crosstalk between Raf and Yki occurs in the heart and can influence Raf-mediated cardiac hypertrophy.

  7. Management of Unilateral Masseter Hypertrophy and Hypertrophic Scar—A Case Report

    PubMed Central

    Shetty, Naresh; Malaviya, Rajanikanth K.; Gupta, M. K.

    2012-01-01

    Masseter muscle hypertrophy is a rare condition of idiopathic cause. It clinically presents as an enlargement of one or both masseter muscles. Most patients complain of facial asymmetry; however, symptoms such as trismus, protrusion, and bruxism may also occur. Several treatment options reported for masseter hypertrophy are present, which range from simple pharmacotherapy to more invasive surgical reduction. Keloid scar with unilateral masseter hypertrophy is a rarely seen in clinical practice. This paper reports a case of unilateral masseter hypertrophy with keloid scar in the angle of the mandible for which surgical treatment was rendered to the patient by using a single approach. PMID:22844620

  8. Isorhamnetin protects against cardiac hypertrophy through blocking PI3K-AKT pathway.

    PubMed

    Gao, Lu; Yao, Rui; Liu, Yuzhou; Wang, Zheng; Huang, Zhen; Du, Binbin; Zhang, Dianhong; Wu, Leiming; Xiao, Lili; Zhang, Yanzhou

    2017-02-07

    Isorhamnetin, a flavonoid compound extracted from the Chinese herb Hippophae rhamnoides L., is well known for its anti-inflammatory, anti-oxidative, anti-adipogenic, anti-proliferative, and anti-tumor activities. However, the role of isorhamnetin in cardiac hypertrophy has not been reported. The aims of the present study were to find whether isorhamnetin could alleviate cardiac hypertrophy and to define the underlying molecular mechanisms. Here, we investigated the effects of isorhamnetin (100 mg/kg/day) on cardiac hypertrophy induced by aortic banding in mice. Cardiac hypertrophy was evaluated by echocardiographic, hemodynamic, pathological, and molecular analyses. Our data demonstrated that isorhamnetin could inhibit cardiac hypertrophy and fibrosis 8 weeks after aortic banding. The results further revealed that the effect of isorhamnetin on cardiac hypertrophy was mediated by blocking the activation of phosphatidylinositol 3-kinase-AKT signaling pathway. In vitro studies performed in neonatal rat cardiomyocytes confirmed that isorhamnetin could attenuate cardiomyocyte hypertrophy induced by angiotensin II, which was associated with phosphatidylinositol 3-kinase-AKT signaling pathway. In conclusion, these data indicate for the first time that isorhamnetin has protective potential for targeting cardiac hypertrophy by blocking the phosphatidylinositol 3-kinase-AKT signaling pathway. Thus, our study suggests that isorhamnetin may represent a potential therapeutic strategy for the treatment of cardiac hypertrophy and heart failure.

  9. Cardiac‐specific Hexokinase 2 Overexpression Attenuates Hypertrophy by Increasing Pentose Phosphate Pathway Flux

    PubMed Central

    McCommis, Kyle S.; Douglas, Diana L.; Krenz, Maike; Baines, Christopher P.

    2013-01-01

    Background The enzyme hexokinase‐2 (HK2) phosphorylates glucose, which is the initiating step in virtually all glucose utilization pathways. Cardiac hypertrophy is associated with a switch towards increased glucose metabolism and decreased fatty acid metabolism. Recent evidence suggests that the increased glucose utilization is compensatory to the down‐regulated fatty acid metabolism during hypertrophy and is, in fact, beneficial. Therefore, we hypothesized that increasing glucose utilization by HK2 overexpression would decrease cardiac hypertrophy. Methods and Results Mice with cardiac‐specific HK2 overexpression displayed decreased hypertrophy in response to isoproterenol. Neonatal rat ventricular myocytes (NRVMs) infected with an HK2 adenovirus similarly displayed decreased hypertrophy in response to phenylephrine. Hypertrophy increased reactive oxygen species (ROS) levels, which were attenuated by HK2 overexpression, thereby decreasing NRVM hypertrophy and death. HK2 appears to modulate ROS via the pentose phosphate pathway, as inhibition of glucose‐6‐phosphate dehydrogenase with dehydroepiandrosterone decreased the ability of HK2 to diminish ROS and hypertrophy. Conclusions These results suggest that HK2 attenuates cardiac hypertrophy by decreasing ROS accumulation via increased pentose phosphate pathway flux. PMID:24190878

  10. Carvedilol-Afforded Protection against Daunorubicin-Induced Cardiomyopathic Rats In Vivo: Effects on Cardiac Fibrosis and Hypertrophy

    PubMed Central

    Arozal, Wawaimuli; Sari, Flori R.; Watanabe, Kenichi; Arumugam, Somasundaram; Veeraveedu, Punniyakoti T.; Ma, Meilei; Thandavarayan, Rajarajan A.; Sukumaran, Vijayakumar; Lakshmanan, Arun Prasath; Kobayashi, Yoshiyasu; Mito, Sayaka; Soetikno, Vivian; Suzuki, Kenji

    2011-01-01

    Anthracyclines, most powerful anticancer agents, suffer from their cardiotoxic effects, which may be due to the induction of oxidative stress. Carvedilol, a third-generation, nonselective β-adrenoreceptor antagonist, possesses both reactive oxygen species (ROS) scavenging and ROS suppressive effects. It showed protective effects against daunorubicin- (DNR-) induced cardiac toxicity by reducing oxidative stress and apoptosis. This study therefore was designed to examine the effects of carvedilol on DNR-induced cardiomyopathic rats, focused on the changes of left ventricular function, cardiac fibrosis, and hypertrophy. Carvedilol increased survival rate, prevented systolic and diastolic dysfunction, and attenuated myocardial fibrosis and hypertrophy. DNR alone treated rats showed upregulated myocardial expression of ANP, PKC-α, OPN, and TGF-β1 and downregulation of GATA-4 in comparison with control, and treatment with carvedilol significantly reversed these changes. The results of the present study add the available evidences on the cardioprotection by carvedilol when associated with anthracyclines and explain the mechanisms underlying the benefits of their coadministration. PMID:22084713

  11. Fate tracing of mature hepatocytes in mouse liver homeostasis and regeneration

    PubMed Central

    Malato, Yann; Naqvi, Syed; Schürmann, Nina; Ng, Raymond; Wang, Bruce; Zape, Joan; Kay, Mark A.; Grimm, Dirk; Willenbring, Holger

    2011-01-01

    Recent evidence has contradicted the prevailing view that homeostasis and regeneration of the adult liver are mediated by self duplication of lineage-restricted hepatocytes and biliary epithelial cells. These new data suggest that liver progenitor cells do not function solely as a backup system in chronic liver injury; rather, they also produce hepatocytes after acute injury and are in fact the main source of new hepatocytes during normal hepatocyte turnover. In addition, other evidence suggests that hepatocytes are capable of lineage conversion, acting as precursors of biliary epithelial cells during biliary injury. To test these concepts, we generated a hepatocyte fate-tracing model based on timed and specific Cre recombinase expression and marker gene activation in all hepatocytes of adult Rosa26 reporter mice with an adenoassociated viral vector. We found that newly formed hepatocytes derived from preexisting hepatocytes in the normal liver and that liver progenitor cells contributed minimally to acute hepatocyte regeneration. Further, we found no evidence that biliary injury induced conversion of hepatocytes into biliary epithelial cells. These results therefore restore the previously prevailing paradigms of liver homeostasis and regeneration. In addition, our new vector system will be a valuable tool for timed, efficient, and specific loop out of floxed sequences in hepatocytes. PMID:22105172

  12. Reversible reactivity by optic nerve astrocytes.

    PubMed

    Sun, Daniel; Qu, Juan; Jakobs, Tatjana C

    2013-08-01

    Reactive astrocytes are typically studied in models that cause irreversible mechanical damage to axons, neuronal cell bodies, and glia. Here, we evaluated the response of astrocytes in the optic nerve head to a subtle injury induced by a brief, mild elevation of the intraocular pressure. Astrocytes demonstrated reactive remodeling that peaked at three days, showing hypertrophy, process retraction, and simplification of their shape. This was not accompanied by any significant changes in the gene expression profile. At no time was there discernible damage to the optic axons, as evidenced by electron microscopy and normal anterograde and retrograde transport. Remarkably, the morphological remodeling was reversible. These findings underscore the plastic nature of reactivity. They show that reactivity can resolve fully if the insult is removed, and suggest that reactivity per se is not necessarily deleterious to axons. This reaction may represent very early events in the sequence that eventually leads to glial scarring.

  13. Mollusc C-reactive protein crosses species barrier and reverses hepatotoxicity of lead in rodent models.

    PubMed

    Mukherjee, Sandip; Chatterjee, Sarmishtha; Sarkar, Shuvasree; Agarwal, Soumik; Kundu, Rakesh; Maitra, Sudipta; Bhattacharya, Shelley

    2013-08-01

    Achatina fulica C-reactive protein (ACRP) reversed the toxic effects of lead nitrate both in vivo in mice and in vitro in rat hepatocytes restoring the basal level of cell viability, lipid peroxidation, reduced glutathione and superoxides. Cytotoxicity was also significantly ameliorated in rat hepatocytes by in vitro pre-treatments with individual subunits (60, 62, 90 and 110 kDa) of ACRP. Annexin V-Cy3/CFDA dual staining showed significant reduction in the number of apoptotic hepatocytes pre-treated with ACRP. ACRP induced restoration of mitochondrial membrane potential was remarkable. ACRP pre-treatment prevented Pb-induced apoptosis mediated by caspase activation. The antagonistic effect of ACRP may be due to scavenging of reactive oxygen species which maintained the homeostasis of cellular redox potential as well as reduced glutathione status. The results suggest that ACRP crosses the species barrier and it may be utilized as a viable exogenous agent of cytoprotection against heavy metal related toxicity.

  14. Muscle hypertrophy induced by myostatin inhibition accelerates degeneration in dysferlinopathy.

    PubMed

    Lee, Yun-Sil; Lehar, Adam; Sebald, Suzanne; Liu, Min; Swaggart, Kayleigh A; Talbot, C Conover; Pytel, Peter; Barton, Elisabeth R; McNally, Elizabeth M; Lee, Se-Jin

    2015-10-15

    Myostatin is a secreted signaling molecule that normally acts to limit muscle growth. As a result, there is extensive effort directed at developing drugs capable of targeting myostatin to treat patients with muscle loss. One potential concern with this therapeutic approach in patients with muscle degenerative diseases like muscular dystrophy is that inducing hypertrophy may increase stress on dystrophic fibers, thereby accelerating disease progression. To investigate this possibility, we examined the effect of blocking the myostatin pathway in dysferlin-deficient (Dysf(-/-)) mice, in which membrane repair is compromised, either by transgenic expression of follistatin in skeletal muscle or by systemic administration of the soluble form of the activin type IIB receptor (ACVR2B/Fc). Here, we show that myostatin inhibition by follistatin transgene expression in Dysf(-/-) mice results in early improvement in histopathology but ultimately exacerbates muscle degeneration; this effect was not observed in dystrophin-deficient (mdx) mice, suggesting that accelerated degeneration induced by follistatin transgene expression is specific to mice lacking dysferlin. Dysf(-/-) mice injected with ACVR2B/Fc showed significant increases in muscle mass and amelioration of fibrotic changes normally seen in 8-month-old Dysf(-/-) mice. Despite these potentially beneficial effects, ACVR2B/Fc treatment caused increases in serum CK levels in some Dysf(-/-) mice, indicating possible muscle damage induced by hypertrophy. These findings suggest that depending on the disease context, inducing muscle hypertrophy by myostatin blockade may have detrimental effects, which need to be weighed against the potential gains in muscle growth and decreased fibrosis.

  15. The molecular basis for load-induced skeletal muscle hypertrophy.

    PubMed

    Marcotte, George R; West, Daniel W D; Baar, Keith

    2015-03-01

    In a mature (weight neutral) animal, an increase in muscle mass only occurs when the muscle is loaded sufficiently to cause an increase in myofibrillar protein balance. A tight relationship between muscle hypertrophy, acute increases in protein balance, and the activity of the mechanistic target of rapamycin complex 1 (mTORC1) was demonstrated 15 years ago. Since then, our understanding of the signals that regulate load-induced hypertrophy has evolved considerably. For example, we now know that mechanical load activates mTORC1 in the same way as growth factors, by moving TSC2 (a primary inhibitor of mTORC1) away from its target (the mTORC activator) Rheb. However, the kinase that phosphorylates and moves TSC2 is different in the two processes. Similarly, we have learned that a distinct pathway exists whereby amino acids activate mTORC1 by moving it to Rheb. While mTORC1 remains at the forefront of load-induced hypertrophy, the importance of other pathways that regulate muscle mass are becoming clearer. Myostatin, is best known for its control of developmental muscle size. However, new mechanisms to explain how loading regulates this process are suggesting that it could play an important role in hypertrophic muscle growth as well. Last, new mechanisms are highlighted for how β2 receptor agonists could be involved in load-induced muscle growth and why these agents are being developed as non-exercise-based therapies for muscle atrophy. Overall, the results highlight how studying the mechanism of load-induced skeletal muscle mass is leading the development of pharmaceutical interventions to promote muscle growth in those unwilling or unable to perform resistance exercise.

  16. Muscle hypertrophy induced by myostatin inhibition accelerates degeneration in dysferlinopathy

    PubMed Central

    Lee, Yun-Sil; Lehar, Adam; Sebald, Suzanne; Liu, Min; Swaggart, Kayleigh A.; Talbot, C. Conover; Pytel, Peter; Barton, Elisabeth R.; McNally, Elizabeth M.; Lee, Se-Jin

    2015-01-01

    Myostatin is a secreted signaling molecule that normally acts to limit muscle growth. As a result, there is extensive effort directed at developing drugs capable of targeting myostatin to treat patients with muscle loss. One potential concern with this therapeutic approach in patients with muscle degenerative diseases like muscular dystrophy is that inducing hypertrophy may increase stress on dystrophic fibers, thereby accelerating disease progression. To investigate this possibility, we examined the effect of blocking the myostatin pathway in dysferlin-deficient (Dysf−/−) mice, in which membrane repair is compromised, either by transgenic expression of follistatin in skeletal muscle or by systemic administration of the soluble form of the activin type IIB receptor (ACVR2B/Fc). Here, we show that myostatin inhibition by follistatin transgene expression in Dysf−/− mice results in early improvement in histopathology but ultimately exacerbates muscle degeneration; this effect was not observed in dystrophin-deficient (mdx) mice, suggesting that accelerated degeneration induced by follistatin transgene expression is specific to mice lacking dysferlin. Dysf−/− mice injected with ACVR2B/Fc showed significant increases in muscle mass and amelioration of fibrotic changes normally seen in 8-month-old Dysf−/− mice. Despite these potentially beneficial effects, ACVR2B/Fc treatment caused increases in serum CK levels in some Dysf−/− mice, indicating possible muscle damage induced by hypertrophy. These findings suggest that depending on the disease context, inducing muscle hypertrophy by myostatin blockade may have detrimental effects, which need to be weighed against the potential gains in muscle growth and decreased fibrosis. PMID:26206886

  17. Temporalis muscle hypertrophy: a new plastic surgery procedure.

    PubMed

    Morselli, P G

    2000-10-01

    Bilateral hypertrophy of the temporal muscle can give the impression of a harsh facial appearance that manifests itself as a morphopsychological conflict for the subject involved (Minotaur syndrome). This article describes a new facial aesthetic surgical procedure in the area of the temporal muscle. The author describes the surgical technique and the surgical instrument that he developed specifically for performing aesthetic contouring of the temporal area by reducing the muscle volume discrepancy ("myosuction"). The follow-up results of 11 cases demonstrated that this procedure renders valid results in the overall aesthetic reharmonization of the face and an improvement of individual psychological well-being.

  18. Dominant negative myostatin produces hypertrophy without hyperplasia in muscle.

    PubMed

    Zhu, X; Hadhazy, M; Wehling, M; Tidball, J G; McNally, E M

    2000-05-26

    Myostatin, a TGF-beta family member, is a negative regulator of muscle growth. Here, we generated transgenic mice that expressed myostatin mutated at its cleavage site under the control of a muscle specific promoter creating a dominant negative myostatin. These mice exhibited a significant (20-35%) increase in muscle mass that resulted from myofiber hypertrophy and not from myofiber hyperplasia. We also evaluated the role of myostatin in muscle degenerative states, such as muscular dystrophy, and found significant downregulation of myostatin. Thus, further inhibition of myostatin may permit increased muscle growth in muscle degenerative disorders.

  19. Tomoregulin-1 prevents cardiac hypertrophy after pressure overload in mice by inhibiting TAK1-JNK pathways.

    PubMed

    Bao, Dan; Lu, Dan; Liu, Ning; Dong, Wei; Lu, Ying-Dong; Qin, Chuan; Zhang, Lian-Feng

    2015-08-01

    Cardiac hypertrophy is associated with many forms of heart disease, and identifying important modifier genes involved in the pathogenesis of cardiac hypertrophy could lead to the development of new therapeutic strategies. Tomoregulin-1 is a growth factor that is primarily involved in embryonic development and adult central nervous system (CNS) function, and it is expressed abnormally in a variety of CNS pathologies. Tomoregulin-1 is also expressed in the myocardium. However, the effects of tomoregulin-1 on the heart, particularly on cardiac hypertrophy, remains unknown. The aim of the study is to examine whether and by what mechanism tomoregulin-1 regulates the development of cardiac hypertrophy induced by pressure overload. In this study, we found that tomoregulin-1 was significantly upregulated in two cardiac hypertrophy models: cTnT(R92Q) transgenic mice and thoracic aorta constriction (TAC)-induced cardiac hypertrophy mice. The transgenic overexpression of tomoregulin-1 increased the survival rate, improved the cardiac geometry and functional parameters of echocardiography, and decreased the degree of cardiac hypertrophy of the TAC mice, whereas knockdown of tomoregulin-1 expression resulted in an opposite phenotype and exacerbated phenotypes of cardiac hypertrophy induced by TAC. A possible mechanism by which tomoregulin-1 regulates the development of cardiac hypertrophy in TAC-induced cardiac hypertrophy is through inhibiting TGFβ non-canonical (TAK1-JNK) pathways in the myocardium. Tomoregulin-1 plays a protective role in the modulation of adverse cardiac remodeling from pressure overload in mice. Tomoregulin-1 could be a therapeutic target to control the development of cardiac hypertrophy.

  20. A Microfabricated Platform for Generating Physiologically-Relevant Hepatocyte Zonation

    PubMed Central

    McCarty, William J.; Usta, O. Berk; Yarmush, Martin L.

    2016-01-01

    In vitro liver models have been important tools for more than 40 years for academic research and preclinical toxicity screening by the pharmaceutical industry. Hepatocytes, the highly metabolic parenchymal cells of the liver, are efficient at different metabolic chemistries depending on their relative spatial location along the sinusoid from the portal triad to the central vein. Although replicating hepatocyte metabolic zonation is vitally important for physiologically-relevant in vitro liver tissue and organ models, it is most often completely overlooked. Here, we demonstrate the creation of spatially-controlled zonation across multiple hepatocyte metabolism levels through the application of precise concentration gradients of exogenous hormone (insulin and glucagon) and chemical (3-methylcholanthrene) induction agents in a microfluidic device. Observed gradients in glycogen storage via periodic acid-Schiff staining, urea production via carbamoyl phosphatase synthetase I staining, and cell viability after exposure to allyl alcohol and acetaminophen demonstrated the in vitro creation of hepatocyte carbohydrate, nitrogen, alcohol degradation, and drug conjugation metabolic zonation. This type of advanced control system will be crucial for studies evaluating drug metabolism and toxicology using in vitro constructs. PMID:27240736

  1. Preservation of hepatocyte suspensions at 4 degrees C.

    PubMed

    Lund, P; Wiggins, D

    1988-10-01

    Suspensions of rat hepatocytes are resistant to hypoxia for at least 24 hr at 4 degrees C. After storage for 24 hr with xylitol, sorbitol, or glycerol, their subsequent capacity for glucogenesis from these substrates is increased. Even storage under N2/CO2 as the gas phase has little deleterious effect.

  2. A Microfabricated Platform for Generating Physiologically-Relevant Hepatocyte Zonation

    NASA Astrophysics Data System (ADS)

    McCarty, William J.; Usta, O. Berk; Yarmush, Martin L.

    2016-05-01

    In vitro liver models have been important tools for more than 40 years for academic research and preclinical toxicity screening by the pharmaceutical industry. Hepatocytes, the highly metabolic parenchymal cells of the liver, are efficient at different metabolic chemistries depending on their relative spatial location along the sinusoid from the portal triad to the central vein. Although replicating hepatocyte metabolic zonation is vitally important for physiologically-relevant in vitro liver tissue and organ models, it is most often completely overlooked. Here, we demonstrate the creation of spatially-controlled zonation across multiple hepatocyte metabolism levels through the application of precise concentration gradients of exogenous hormone (insulin and glucagon) and chemical (3-methylcholanthrene) induction agents in a microfluidic device. Observed gradients in glycogen storage via periodic acid-Schiff staining, urea production via carbamoyl phosphatase synthetase I staining, and cell viability after exposure to allyl alcohol and acetaminophen demonstrated the in vitro creation of hepatocyte carbohydrate, nitrogen, alcohol degradation, and drug conjugation metabolic zonation. This type of advanced control system will be crucial for studies evaluating drug metabolism and toxicology using in vitro constructs.

  3. Aniline Induces Oxidative Stress and Apoptosis of Primary Cultured Hepatocytes.

    PubMed

    Wang, Yue; Gao, Hong; Na, Xiao-Lin; Dong, Shu-Ying; Dong, Hong-Wei; Yu, Jia; Jia, Li; Wu, Yong-Hui

    2016-11-30

    The toxicity and carcinogenicity of aniline in humans and animals have been well documented. However, the molecular mechanism involved in aniline-induced liver toxicity and carcinogenesis remains unclear. In our research, primary cultured hepatocytes were exposed to aniline (0, 1.25, 2.50, 5.0 and 10.0 μg/mL) for 24 h in the presence or absence of N-acetyl-l-cysteine (NAC). Levels of reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH), activities of superoxide dismutase (SOD) and catalase (CAT), mitochondrial membrane potential, DNA damage, cell viability, and apoptosis were detected. Levels of ROS and MDA were significantly increased and levels of GSH and CAT, activity of SOD, and mitochondrial membrane potential in hepatocytes were significantly decreased by aniline compared with the negative control group. The tail moment and DNA content of the tail in exposed groups were significantly higher than those in the negative control group. Cell viability was reduced and apoptotic death was induced by aniline in a concentration-dependent manner. The phenomena of ROS generation, oxidative damage, loss of mitochondrial membrane potential, DNA damage and apoptosis could be prevented if ROS inhibitor NAC was added. ROS generation is involved in the loss of mitochondrial membrane potential and DNA injury, which may play a role in aniline-induced apoptosis in hepatocytes. Our study provides insight into the mechanism of aniline-induced toxicity and apoptosis of hepatocytes.

  4. Liver glycogen bodies: ground-glass hepatocytes in transplanted patients.

    PubMed

    Bejarano, Pablo A; Garcia, Monica T; Rodriguez, Maria M; Ruiz, Phillip; Tzakis, Andreas G

    2006-11-01

    Ground-glass hepatocytes have been described in Lafora's disease, fibrinogen deposition, hepatitis B, type IV glycogenosis, and alcohol aversion (cyanamide) therapy. We encountered ground-glass hepatocytes with intracytoplasmic inclusions in four liver biopsies from three transplanted patients who had none of the above-mentioned underlying diseases. One patient was a 4-year-old boy who had a kidney transplant for severe ureterovesical reflux. Patient 2 was a 52-year-old man who had two liver transplants because of hepatitis C. The third patient was a 7-month-old girl who underwent a multivisceral transplant because of necrotizing enterocolitis and liver failure induced by total parenteral nutrition. The patients developed liver abnormalities from 45 days to 4 years after their transplants. The livers showed conspicuous ground-glass hepatocytes in 90% of the children's samples and 30% of the adult liver cells. The cytoplasmic bodies stained strongly for Gomori methenamine-silver; they were positive for periodic acid-Schiff without diastase, but negative after diastase digestion. They were negative for colloidal iron and hepatitis B core and surface antigens. Electron microscopy revealed non-membrane bound aggregates of glycogen. Idiopathic ground-glass hepatocytes occur in transplanted patients and represent accumulation of altered glycogen. However, their clinical significance and cause are not entirely elucidated.

  5. Octylphenol induces vitellogenin production and cell death in fish hepatocytes

    SciTech Connect

    Toomey, B.H.; Monteverdi, G.H.; Di Giulio, R.T.

    1999-04-01

    The effects of octylphenol (OP) on vitellogenin production and cell death in hepatocytes from brown bullhead catfish (Americurus nebulosus) were studied. Production of vitellogenin was induced in hepatocytes exposed to 10 to 50 {micro}M OP, whereas a higher concentration of OP (100 {micro}M) induced apoptotic cell death. By 3 h after the addition of 100 {micro}M OP, dying cells showed chromatin condensation and DNA fragmentation as determined by fluorescence microscopy and gel electrophoresis. Later stages of cell death (nuclear membrane breakdown and cell fragmentation into apoptotic bodies) were identified in cells exposed to OP for at least 6 h. Hepatocytes exposed to 100 {micro}M OP also produced less vitellogenin than cells exposed to 50 {micro}M OP. An estrogen receptor antagonist, tamoxifen, greatly decreased vitellogenin production in OP-exposed hepatocytes from male fish but did not decrease cell death in these cells. Thus, although the ability of OP to induce vitellogenin production is likely mediated through interactions with the estrogen receptor, the induction of apoptotic cell death by OP does not appear to be dependent on its estrogenic activity but may be a more general toxic effect.

  6. INTERINDIVIDUAL VARIATION IN THE METABOLISM OF ARSENIC IN HUMAN HEPATOCYTES

    EPA Science Inventory


    The liver is the major site for the enzymatic methylation of inorganic arsenic (iAs) in humans. Primary cultures of normal human hepatocytes isolated from tissue obtained at surgery or from donor livers have been used to study interindividual variation in the capacity of live...

  7. 3D Cultivation Techniques for Primary Human Hepatocytes

    PubMed Central

    Bachmann, Anastasia; Moll, Matthias; Gottwald, Eric; Nies, Cordula; Zantl, Roman; Wagner, Helga; Burkhardt, Britta; Sánchez, Juan J. Martínez; Ladurner, Ruth; Thasler, Wolfgang; Damm, Georg; Nussler, Andreas K.

    2015-01-01

    One of the main challenges in drug development is the prediction of in vivo toxicity based on in vitro data. The standard cultivation system for primary human hepatocytes is based on monolayer cultures, even if it is known that these conditions result in a loss of hepatocyte morphology and of liver-specific functions, such as drug-metabolizing enzymes and transporters. As it has been demonstrated that hepatocytes embedded between two sheets of collagen maintain their function, various hydrogels and scaffolds for the 3D cultivation of hepatocytes have been developed. To further improve or maintain hepatic functions, 3D cultivation has been combined with perfusion. In this manuscript, we discuss the benefits and drawbacks of different 3D microfluidic devices. For most systems that are currently available, the main issues are the requirement of large cell numbers, the low throughput, and expensive equipment, which render these devices unattractive for research and the drug-developing industry. A higher acceptance of these devices could be achieved by their simplification and their compatibility with high-throughput, as both aspects are of major importance for a user-friendly device. PMID:27600213

  8. DIFFERENTIATING MECHANISMS OF REACTIVE CHEMICAL TOXICITY IN ISOLATED TROUT HEPATOCYTES

    EPA Science Inventory

    The toxicity of four quinones, 2,3-dimethoxy-1,4-naphthoquinone (DMONQ), 2-methyl 1,4-naphthoquinone (MNQ ),1,4-naphthoquinone (NQ), and 1,4-benzoquinone (BQ), which redox cycle or arlyate in mammalian cells, was determined in isolated trout (Oncorhynchus mykiss) hepatocytes. Mor...

  9. Retinoic Acid-mediated Nuclear Receptor Activation and Hepatocyte Proliferation

    PubMed Central

    Bushue, Nathan; Wan, Yu-Jui Yvonne

    2016-01-01

    Due to their well-known differentiation and apoptosis-inducing abilities, retinoic acid (RA) and its analogs have strong anti-cancer efficacy in human cancers. However, in vivo RA is a liver mitogen. While speculation has persisted that RA-mediated signaling is likely involved in hepatocyte proliferation during liver regeneration, direct evidence is still required. Findings in support of this proposition include observations that a release of retinyl palmitate (the precursor of RA) occurs in liver stellate cells following liver injury. Nevertheless, the biological action of this released vitamin A is virtually unknown. More likely is that the released vitamin A is converted to RA, the biological form, and then bound to a specific receptor (retinoid x receptor; RXRα), which is most abundantly expressed in the liver. Considering the mitogenic effects of RA, the RA-activated RXRα would likely then influence hepatocyte proliferation and liver tissue repair. At present, the mechanism by which RA stimulates hepatocyte proliferation is largely unknown. This review summarizes the activation of nuclear receptors (peroxisome proliferator activated receptor-α, pregnane x receptor, constitutive androstane receptor, and farnesoid x receptor) in an RXRα dependent manner to induce hepatocyte proliferation, providing a link between RA and its proliferative role. PMID:27635169

  10. Asialoglycoprotein receptor mediated hepatocyte targeting - strategies and applications.

    PubMed

    D'Souza, Anisha A; Devarajan, Padma V

    2015-04-10

    Hepatocyte resident afflictions continue to affect the human population unabated. The asialoglycoprotein receptor (ASGPR) is primarily expressed on hepatocytes and minimally on extra-hepatic cells. This makes it specifically attractive for receptor-mediated drug delivery with minimum concerns of toxicity. ASGPR facilitates internalization by clathrin-mediated endocytosis and exhibits high affinity for carbohydrates specifically galactose, N-acetylgalactosamine and glucose. Isomeric forms of sugar, galactose density and branching, spatial geometry and galactose linkages are key factors influencing ligand-receptor binding. Popular ligands for ASGPR mediated targeting are carbohydrate polymers, arabinogalactan and pullulan. Other ligands include galactose-bearing glycoproteins, glycopeptides and galactose modified polymers and lipids. Drug-ligand conjugates provide a viable strategy; nevertheless ligand-anchored nanocarriers provide an attractive option for ASGPR targeted delivery and are widely explored. The present review details various ligands and nanocarriers exploited for ASGPR mediated delivery of drugs to hepatocytes. Nanocarrier properties affecting ASGPR mediated uptake are discussed at length. The review also highlights the clinical relevance of ASGPR mediated targeting and applications in diagnostics. ASGPR mediated hepatocyte targeting provides great promise for improved therapy of hepatic afflictions.

  11. Aniline Induces Oxidative Stress and Apoptosis of Primary Cultured Hepatocytes

    PubMed Central

    Wang, Yue; Gao, Hong; Na, Xiao-Lin; Dong, Shu-Ying; Dong, Hong-Wei; Yu, Jia; Jia, Li; Wu, Yong-Hui

    2016-01-01

    The toxicity and carcinogenicity of aniline in humans and animals have been well documented. However, the molecular mechanism involved in aniline-induced liver toxicity and carcinogenesis remains unclear. In our research, primary cultured hepatocytes were exposed to aniline (0, 1.25, 2.50, 5.0 and 10.0 μg/mL) for 24 h in the presence or absence of N-acetyl-l-cysteine (NAC). Levels of reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH), activities of superoxide dismutase (SOD) and catalase (CAT), mitochondrial membrane potential, DNA damage, cell viability, and apoptosis were detected. Levels of ROS and MDA were significantly increased and levels of GSH and CAT, activity of SOD, and mitochondrial membrane potential in hepatocytes were significantly decreased by aniline compared with the negative control group. The tail moment and DNA content of the tail in exposed groups were significantly higher than those in the negative control group. Cell viability was reduced and apoptotic death was induced by aniline in a concentration-dependent manner. The phenomena of ROS generation, oxidative damage, loss of mitochondrial membrane potential, DNA damage and apoptosis could be prevented if ROS inhibitor NAC was added. ROS generation is involved in the loss of mitochondrial membrane potential and DNA injury, which may play a role in aniline-induced apoptosis in hepatocytes. Our study provides insight into the mechanism of aniline-induced toxicity and apoptosis of hepatocytes. PMID:27916916

  12. TEMPORAL CHANGE IN GAP JUNCTION FUNCTION IN PRIMARY HEPATOCYTES

    EPA Science Inventory

    TEMPORAL CHANGES IN GAP JUNCTION FUNCTION IN PRIMARY *

    The objective of this study was to examine the reduction in gap junction communication (GJC) in primary hepatocytes due to coincident melatonin and magnetic field treatments to determine if these conditions could prov...

  13. Hepatocytes: a key cell type for innate immunity

    PubMed Central

    Zhou, Zhou; Xu, Ming-Jiang; Gao, Bin

    2016-01-01

    Hepatocytes, the major parenchymal cells in the liver, play pivotal roles in metabolism, detoxification, and protein synthesis. Hepatocytes also activate innate immunity against invading microorganisms by secreting innate immunity proteins. These proteins include bactericidal proteins that directly kill bacteria, opsonins that assist in the phagocytosis of foreign bacteria, iron-sequestering proteins that block iron uptake by bacteria, several soluble factors that regulate lipopolysaccharide signaling, and the coagulation factor fibrinogen that activates innate immunity. In this review, we summarize the wide variety of innate immunity proteins produced by hepatocytes and discuss liver-enriched transcription factors (e.g. hepatocyte nuclear factors and CCAAT/enhancer-binding proteins), pro-inflammatory mediators (e.g. interleukin (IL)-6, IL-22, IL-1β and tumor necrosis factor-α), and downstream signaling pathways (e.g. signal transducer and activator of transcription factor 3 and nuclear factor-κB) that regulate the expression of these innate immunity proteins. We also briefly discuss the dysregulation of these innate immunity proteins in chronic liver disease, which may contribute to an increased susceptibility to bacterial infection in patients with cirrhosis. PMID:26685902

  14. Pleiotrophin commits human bone marrow mesenchymal stromal cells towards hypertrophy during chondrogenesis.

    PubMed

    Bouderlique, Thibault; Henault, Emilie; Lebouvier, Angelique; Frescaline, Guilhem; Bierling, Phillipe; Rouard, Helene; Courty, José; Albanese, Patricia; Chevallier, Nathalie

    2014-01-01

    Pleiotrophin (PTN) is a growth factor present in the extracellular matrix of the growth plate during bone development and in the callus during bone healing. Bone healing is a complicated process that recapitulates endochondral bone development and involves many cell types. Among those cells, mesenchymal stromal cells (MSC) are able to differentiate toward chondrogenic and osteoblastic lineages. We aimed to determine PTN effects on differentiation properties of human bone marrow stromal cells (hBMSC) under chondrogenic induction using histological analysis and quantitative reverse transcription polymerase chain reaction. PTN dramatically potentiated chondrogenic differentiation as indicated by a strong increase of collagen 2 protein, and cartilage-related gene expression. Moreover, PTN increased transcription of hypertrophic chondrocyte markers such as MMP13, collagen 10 and alkaline phosphatase and enhanced calcification and the content of collagen 10 protein. These effects are dependent on PTN receptors signaling and PI3 K pathway activation. These data suggest a new role of PTN in bone regeneration as an inducer of hypertrophy during chondrogenic differentiation of hBMSC.

  15. Compromised epidermal barrier stimulates Harderian gland activity and hypertrophy in ACBP−/− mice[S

    PubMed Central

    Bek, Signe; Neess, Ditte; Dixen, Karen; Bloksgaard, Maria; Marcher, Ann-Britt; Chemnitz, John; Færgeman, Nils J.; Mandrup, Susanne

    2015-01-01

    Acyl-CoA binding protein (ACBP) is a small, ubiquitously expressed intracellular protein that binds C14-C22 acyl-CoA esters with very high affinity and specificity. We have recently shown that targeted disruption of the Acbp gene leads to a compromised epidermal barrier and that this causes delayed adaptation to weaning, including the induction of the hepatic lipogenic and cholesterogenic gene programs. Here we show that ACBP is highly expressed in the Harderian gland, a gland that is located behind the eyeball of rodents and involved in the production of fur lipids and lipids used for lubrication of the eye lid. We show that disruption of the Acbp gene leads to a significant enlargement of this gland with hypertrophy of the acinar cells and increased de novo synthesis of monoalkyl diacylglycerol, the main lipid species produced by the gland. Mice with conditional targeting of the Acbp gene in the epidermis recapitulate this phenotype, whereas generation of an artificial epidermal barrier during gland development reverses the phenotype. Our findings indicate that the Harderian gland is activated by the compromised epidermal barrier as an adaptive and protective mechanism to overcome the barrier defect. PMID:26142722

  16. Compromised epidermal barrier stimulates Harderian gland activity and hypertrophy in ACBP-/- mice.

    PubMed

    Bek, Signe; Neess, Ditte; Dixen, Karen; Bloksgaard, Maria; Marcher, Ann-Britt; Chemnitz, John; Færgeman, Nils J; Mandrup, Susanne

    2015-09-01

    Acyl-CoA binding protein (ACBP) is a small, ubiquitously expressed intracellular protein that binds C14-C22 acyl-CoA esters with very high affinity and specificity. We have recently shown that targeted disruption of the Acbp gene leads to a compromised epidermal barrier and that this causes delayed adaptation to weaning, including the induction of the hepatic lipogenic and cholesterogenic gene programs. Here we show that ACBP is highly expressed in the Harderian gland, a gland that is located behind the eyeball of rodents and involved in the production of fur lipids and lipids used for lubrication of the eye lid. We show that disruption of the Acbp gene leads to a significant enlargement of this gland with hypertrophy of the acinar cells and increased de novo synthesis of monoalkyl diacylglycerol, the main lipid species produced by the gland. Mice with conditional targeting of the Acbp gene in the epidermis recapitulate this phenotype, whereas generation of an artificial epidermal barrier during gland development reverses the phenotype. Our findings indicate that the Harderian gland is activated by the compromised epidermal barrier as an adaptive and protective mechanism to overcome the barrier defect.

  17. Relevance of mouse models of cardiac fibrosis and hypertrophy in cardiac research.

    PubMed

    Rai, Vikrant; Sharma, Poonam; Agrawal, Swati; Agrawal, Devendra K

    2017-01-01

    Heart disease causing cardiac cell death due to ischemia-reperfusion injury is a major cause of morbidity and mortality in the United States. Coronary heart disease and cardiomyopathies are the major cause for congestive heart failure, and thrombosis of the coronary arteries is the most common cause of myocardial infarction. Cardiac injury is followed by post-injury cardiac remodeling or fibrosis. Cardiac fibrosis is characterized by net accumulation of extracellular matrix proteins in the cardiac interstitium and results in both systolic and diastolic dysfunctions. It has been suggested by both experimental and clinical evidence that fibrotic changes in the heart are reversible. Hence, it is vital to understand the mechanism involved in the initiation, progression, and resolution of cardiac fibrosis to design anti-fibrotic treatment modalities. Animal models are of great importance for cardiovascular research studies. With the developing research field, the choice of selecting an animal model for the proposed research study is crucial for its outcome and translational purpose. Compared to large animal models for cardiac research, the mouse model is preferred by many investigators because of genetic manipulations and easier handling. This critical review is focused to provide insight to young researchers about the various mouse models, advantages and disadvantages, and their use in research pertaining to cardiac fibrosis and hypertrophy.

  18. [Use of xenogenic lyophilized hepatocytes in the treatment of acute and chronic liver diseases].

    PubMed

    Musselius, S G; Vasina, N V; Gladskikh, L V

    1998-01-01

    Therapeutic effect of lyophilized xenogenic hepatocytes was demonstrated on 30 dogs with acute hepatic failure and on white mice. The major biochemical values were corrected and the yeast fermentation test showed biological activity of isolated hepatocytes. Clinically, lyophilized hepatocytes were used in the treatment of patients with acute hepatic failure: orally in 47 and for extracorporeal dialysis in 8. The therapeutic effect of lyophilized hepatocytes is based on active detoxication and hemostasis correction. Clinical, laboratory, and instrumental studies showed improvement of the clinical status, decreased encephalopathy, and accelerated repair processes in the liver. Addition of lyophilized hepatocytes to combined therapy decreased the mortality by 2.5 times.

  19. Hepatocyte cytotoxicity induced by hydroperoxide (oxidative stress model) or glyoxal (carbonylation model): prevention by bioactive nut extracts or catechins.

    PubMed

    Banach, Monica S; Dong, Qiang; O'Brien, Peter J

    2009-03-16

    Carbonyl and oxidative stress play important roles in the development of diabetic complications and have been shown to be augmented by various natural compounds and pharmacological agents. Nuts are a rich source of bioactive compounds and antioxidants and various beneficial health effects of nuts have been reported. This study was conducted to evaluate the cytoprotectiveness of various nut extracts and bioactive compounds found in nuts for decreasing cytotoxicity, lipid peroxidation and protein carbonylation in cell toxicity models of diabetes-related carbonyl (glyoxal) and oxidative stress (hydroperoxide). Methanol, ethyl acetate or water were used to prepare crude hazelnut and walnut extracts, which were then used to screen for in vitro cytoprotection of freshly isolated rat hepatocytes against these toxins. The order of protection by nut extracts against hydroperoxide induced cell death was: walnut methanolic extract>walnut aqueous extract>lipophilic walnut extract>hazelnut aqueous extract>hazelnut methanolic extract whereas the lipophilic hazelnut extract did not protect against cell death. The order of protection against lipid peroxidation was the same except for the hazelnut methanolic extract, which prevented lipid peroxidation better than the hazelnut aqueous extract. Catechin, epicatechin and epigallocatechin gallate (EGCG) were investigated for possible protective effects against carbonyl stress cell death and protein carbonylation in hepatocytes. Catechin protected against glyoxal induced cell death and protein carbonylation, and even elicited protection when added to hepatocytes 30 min after the addition of glyoxal. When catechin and epicatechin were compared for protectiveness against glyoxal induced carbonyl stress in hepatocytes, epicatechin protected more effectively than catechin against cell death and protein carbonylation at 120 min. Both compounds also elicited better protection when premixed with glyoxal before addition to hepatocytes, compared

  20. Altered expression of GADD45 genes during the development of chemical-mediated liver hypertrophy and liver tumor promotion in rats.

    PubMed

    Ozawa, Shogo; Gamou, Toshie; Habano, Wataru; Inoue, Kaoru; Yoshida, Midori; Nishikawa, Akiyoshi; Nemoto, Kiyomitsu; Degawa, Masakuni

    2011-10-01

    The purpose of our study was to examine the altered gene expression associated with nongenotoxic chemical-mediated liver hypertrophy and successive liver tumor promotion. Five-week-old male rats were fed a basal diet or a diet containing phenobarbital (PB) or clofibrate (CF) for 3 days, 4 weeks, and 13 weeks. Hepatic expression profiling of cell growth- and stress-related genes, as well as those involved in xenobiotic metabolism, was performed by DNA microarray and/or real time quantitative reverse transcription-polymerase chain reaction. The induction of liver hypertrophy and hepatic cytochrome P450 (CYP) isoforms (CYP2B1/2B2 for PB and CYP4A1 for CF) by PB and CF were clearly observed at all the treatment periods examined. Genes encoding DNA damage-inducible 45 (GADD45) family proteins, in particular GADD45g (GADD45 gamma) were down-regulated by treatment with either PB or CF for 4 and 13 weeks. The chemical-mediated development of liver hypertrophy, induction of hepatic CYPs, and suppression of hepatic GADD45g gene at week 13 disappeared at 4 weeks following cessation of the chemical treatment. Additionally, DNA microarray data indicated that cell cycle-related genes such as cyclins CCNB1 and CCNA2 and cyclin-dependent kinase inhibitor CDKN3 were also down-regulated by treatment with either PB or CF at 13 weeks. Since GADD45 functions as a chemical and radiation stress sensor by interacting with cyclins and cyclin-dependent kinase inhibitors, the decrease in the gene expression of GADD45g mRNA observed in this study, may be associated with nongenotoxic chemical-induced tumor promotion of hepatocarcinogenesis rather than liver hypertrophy.

  1. Co-Activation of Nuclear Factor-κB and Myocardin/Serum Response Factor Conveys the Hypertrophy Signal of High Insulin Levels in Cardiac Myoblasts*

    PubMed Central

    Madonna, Rosalinda; Geng, Yong-Jian; Bolli, Roberto; Rokosh, Gregg; Ferdinandy, Peter; Patterson, Cam; De Caterina, Raffaele

    2014-01-01

    Hyperinsulinemia contributes to cardiac hypertrophy and heart failure in patients with the metabolic syndrome and type 2 diabetes. Here, high circulating levels of tumor necrosis factor (TNF)-α may synergize with insulin in signaling inflammation and cardiac hypertrophy. We tested whether high insulin affects activation of TNF-α-induced NF-κB and myocardin/serum response factor (SRF) to convey hypertrophy signaling in cardiac myoblasts. In canine cardiac myoblasts, treatment with high insulin (10−8 to 10−7 m) for 0–24 h increased insulin receptor substrate (IRS)-1 phosphorylation at Ser-307, decreased protein levels of chaperone-associated ubiquitin (Ub) E3 ligase C terminus of heat shock protein 70-interacting protein (CHIP), increased SRF activity, as well as β-myosin heavy chain (MHC) and myocardin expressions. Here siRNAs to myocardin or NF-κB, as well as CHIP overexpression prevented (while siRNA-mediated CHIP disruption potentiated) high insulin-induced SR element (SRE) activation and β-MHC expression. Insulin markedly potentiated TNF-α-induced NF-κB activation. Compared with insulin alone, insulin+TNF-α increased SRF/SRE binding and β-MHC expression, which was reversed by the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) and by NF-κB silencing. In the hearts of db/db diabetic mice, in which Akt phosphorylation was decreased, p38MAPK, Akt1, and IRS-1 phosphorylation at Ser-307 were increased, together with myocardin expression as well as SRE and NF-κB activities. In response to high insulin, cardiac myoblasts increase the expression or the promyogenic transcription factors myocardin/SRF in a CHIP-dependent manner. Insulin potentiates TNF-α in inducing NF-κB and SRF/SRE activities. In hyperinsulinemic states, myocardin may act as a nuclear effector of insulin, promoting cardiac hypertrophy. PMID:24855642

  2. High glucose enhances microRNA-26a to activate mTORC1 for mesangial cell hypertrophy and matrix protein expression

    PubMed Central

    Dey, Nirmalya; Bera, Amit; Das, Falguni; Ghosh-Choudhury, Nandini; Kasinath, Balakuntalam S.; Choudhury, Goutam Ghosh

    2015-01-01

    High glucose milieu inhibits PTEN expression to activate Akt kinase and induces glomerular mesangial cell hypertrophy and matrix protein expression in diabetic nephropathy. Specific mechanism by which high glucose inhibits PTEN expression is not clear. We found that high glucose increased the expression of the microRNA-26a (miR-26a) in mesangial cells. Using a sensor plasmid with 3’UTR-driven luciferase, we showed PTEN as a target of miR-26a in response to high glucose. Overexpression of miR-26a reduced the PTEN protein levels resulting in increased Akt kinase activity similar to high glucose treatment. In contrast, anti-miR-26a reversed high glucose-induced suppression of PTEN with concomitant inhibition of Akt kinase activity. Akt-mediated phosphorylation of tuberin and PRAS40 regulates mTORC1, which is necessary for mesangial cell hypertrophy and matrix protein expression. Inhibition of high glucose-induced miR-26a blocked phosphorylation of tuberin and PRAS40, which lead to suppression of phosphorylation of S6 kinase and 4EBP-1, two substrates of mTORC1. Furthermore, we show that expression of miR-26a induced mesangial cell hypertrophy and increased fibronectin and collagen I (α2) expression similar to that observed with the cells incubated with high glucose. Anti-miR-26a inhibited these phenomena in response to high glucose. Together our results provide the first evidence for the involvement of miR-26a in high glucose-induced mesangial cell hypertrophy and matrix protein expression. These data indicate the potential therapeutic utility of anti-miR-26a for the complications of diabetic kidney disease. PMID:25797045

  3. Enzymatic antioxidant defense in isolated rat hepatocytes exposed to cadmium.

    PubMed

    Skrzycki, M; Czeczot, H; Majewska, M; Podsiad, M; Karlik, W; Grono, D; Wiechetek, M

    2010-01-01

    The aim of the study was the evaluation of cadmium effects on the activity of antioxidant enzymes in rat hepatocytes. The studies were conducted with isolated rat hepatocytes incubated for 1 or 2 hours in a modified (deprived of carbonates with phosphates) Williams' E medium (MWE) in the presence of cadmium chloride (25, 50 and 200 microM). Hepatocytes incubated in the MWE medium without cadmium chloride were used as a control. The application of the modified Williams' E medium allowed for the appearance of cadmium compounds in a soluble form that is indispensable for suitable estimation of its toxic action. There were evaluated markers of the oxidative stress such as: concentration of thiobarbiturate reactive substances (TBARS)--proportional to the level of lipid peroxidation, concentration of reduced glutathione (GSH), and the activity of antioxidant enzymes, including superoxide dismutase (SOD1 and SOD2), catalase (CAT), total glutathione peroxidase (GSHPx), selenium--dependent glutathione peroxidase (SeGSHPx), glutathione transferase (GST) and glutathione reductase (GSHR). Alterations of antioxidant enzymes activity, the level of TBARS and GSH in isolated rat hepatocytes caused by cadmium in vitro, were shown to depend on the concentration and time of exposure of cells to this metal. The increased level of TBARS and GSH was observed as well as changes in the activity of antioxidant enzymes. The activity of SOD isoenzymes and CAT was increased, whereas GSHPx and GST were decreased. These results indicate that cadmium induces oxidative stress followed by alterations in the cellular antioxidant enzyme system in isolated rat hepatocytes.

  4. Epigallocatechin-3-gallate ameliorates insulin resistance in hepatocytes.

    PubMed

    Ma, Shan-Bo; Zhang, Rui; Miao, Shan; Gao, Bin; Lu, Yang; Hui, Sen; Li, Long; Shi, Xiao-Peng; Wen, Ai-Dong

    2017-04-07

    Hyperglycemia is a typical pathogenic factor in a series of complications among patients with type II diabetes. Epigallocatechin-3-gallate (EGCG) is the major polyphenol extracted from green tea and is reported to be an antioxidant. The aim of the present study was to examine the effect of EGCG on insulin resistance in human HepG2 cells pretreated with high concentrations of glucose. The protein kinase B (AKT)/glycogen synthase kinase (GSK) pathways were analyzed using western blot analysis in HepG2 cells and primary mouse hepatocytes treated with high glucose and/or EGCG. Cellular glycogen content was determined using a glycogen assay kit. Reactive oxygen species (ROS) production was determined using dihydroethidium staining and flow cytometry. c‑JUN N‑terminal kinase (JNK)/insulin receptor substrate 1 (IRS1)/AKT/GSK signaling was explored using western blot analysis in HepG2 cells treated with high glucose and/or EGCG or N-acetyl-cysteine. High glucose significantly decreased the levels of phosphorylated AKT and GSK in HepG2 cells and mouse primary hepatocytes. Pretreatment with EGCG significantly restored the activation of AKT and GSK in HepG2 cells and primary hepatocytes exposed to high glucose. In HepG2 cells and primary hepatocytes, glycogen synthesis was improved by EGCG treatment in a dose‑dependent manner. High glucose significantly stimulated the production of ROS while EGCG protected high glucose‑induced ROS production. ROS is known to serve a major role in high glucose induced‑insulin resistance by increasing JNK and IRS1 serine phosphorylation. In the present study, EGCG was observed to enhance the insulin‑signaling pathway. EGCG ameliorated high glucose‑induced insulin resistance in the hepatocytes by potentially decreasing ROS‑induced JNK/IRS1/AKT/GSK signaling.

  5. Epidermal growth factor-stimulated protein phosphorylation in rat hepatocytes

    SciTech Connect

    Connelly, P.A.; Sisk, R.B.; Johnson, R.M.; Garrison, J.C.

    1987-05-01

    Epidermal growth factor (EGF) causes a 6-fold increase in the phosphorylation state of a cytosolic protein (pp36, M/sub r/ = 36,000, pI = 5.5) in hepatocytes isolated from fasted, male, Wistar rats. Stimulation of /sup 32/P incorporation is observed as early as 1 min following treatment of hepatocytes with EGF and is still present at 30 min after exposure to the growth factor. The phosphate incorporated into pp36 in response to EGF is located predominantly in serine but not tyrosine residues. Phosphorylation of pp36 does not occur in response to insulin or to agents which specifically activate the cAMP-dependent protein kinase (S/sub p/ -cAMPS), protein kinase C (PMA) or Ca/sup 2 +//calmodulin-dependent protein kinases (A23187) in these cells. Prior treatment of hepatocytes with the cAMP analog, S/sub p/-cAMPS, or ADP-ribosylation of N/sub i/, the inhibitory GTP-binding protein of the adenylate cyclase complex, does not prevent EGF-stimulated phosphorylation of pp36. However, as seen in other cell types, pretreatment of hepatocytes with PMA abolishes all EGF-mediated responses including phosphorylation of pp36. These results suggest that EGP specifically activates an uncharacterized, serine protein kinase in hepatocytes that is distal to the intrinsic EGF receptor tyrosine protein kinase. The rapid activation of this kinase suggests that it may play an important role in the early response of the cell to EGF.

  6. Augmenter of liver regeneration (ALR) protects human hepatocytes against apoptosis

    SciTech Connect

    Ilowski, Maren; Kleespies, Axel; Toni, Enrico N. de; Donabauer, Barbara; Jauch, Karl-Walter; Hengstler, Jan G.; Thasler, Wolfgang E.

    2011-01-07

    Research highlights: {yields} ALR decreases cytochrome c release from mitochondria. {yields} ALR protects hepatocytes against apoptosis induction by ethanol, TRAIL, anti-Apo, TGF-{beta} and actinomycin D. {yields} ALR exerts a liver-specific anti-apoptotic effect. {yields} A possible medical usage of ALR regarding protection of liver cells during apoptosis inducing therapies. -- Abstract: Augmenter of liver regeneration (ALR) is known to support liver regeneration and to stimulate proliferation of hepatocytes. However, it is not known if ALR exerts anti-apoptotic effects in human hepatocytes and whether this protective effect is cell type specific. This is relevant, because compounds that protect the liver against apoptosis without undesired effects, such as protection of metastatic tumour cells, would be appreciated in several clinical settings. Primary human hepatocytes (phH) and organotypic cancer cell lines were exposed to different concentrations of apoptosis inducers (ethanol, TRAIL, anti-Apo, TGF-{beta}, actinomycin D) and cultured with or without recombinant human ALR (rhALR). Apoptosis was evaluated by the release of cytochrome c from mitochondria and by FACS with propidium iodide (PI) staining. ALR significantly decreased apoptosis induced by ethanol, TRAIL, anti-Apo, TGF-{beta} and actinomycin D. Further, the anti-apoptotic effect of ALR was observed in primary human hepatocytes and in HepG2 cells but not in bronchial (BC1), colonic (SW480), gastric (GC1) and pancreatic (L3.6PL) cell lines. Therefore, the hepatotrophic growth factor ALR acts in a liver specific manner with regards to both its mitogenic and its anti-apoptotic effect. Unlike the growth factors HGF and EGF, rhALR acts in a liver specific manner. Therefore, ALR is a promising candidate for further evaluation as a possible hepatoprotective factor in clinical settings.

  7. Characterization of aldehyde oxidase enzyme activity in cryopreserved human hepatocytes.

    PubMed

    Hutzler, J Matthew; Yang, Young-Sun; Albaugh, Daniel; Fullenwider, Cody L; Schmenk, Jennifer; Fisher, Michael B

    2012-02-01

    Substrates of aldehyde oxidase (AO), for which human clinical pharmacokinetics are reported, were selected and evaluated in pooled mixed-gender cryopreserved human hepatocytes in an effort to quantitatively characterize AO activity. Estimated hepatic clearance (Cl(h)) for BIBX1382, carbazeran, O⁶-benzylguanine, zaleplon, and XK-469 using cryopreserved hepatocytes was 18, 17, 12, <4.3, and <4.3 ml · min⁻¹ · kg⁻¹, respectively. The observed metabolic clearance in cryopreserved hepatocytes was confirmed to be a result of AO-mediated metabolism via two approaches. Metabolite identification after incubations in the presence of H₂¹⁸O confirmed that the predominant oxidative metabolite was generated by AO, as expected isotope patterns in mass spectra were observed after analysis by high-resolution mass spectrometry. Second, clearance values were efficiently attenuated upon coincubation with hydralazine, an inhibitor of AO. The low exposure after oral doses of BIBX1382 and carbazeran (∼5% F) would have been fairly well predicted using simple hepatic extraction (f(h)) values derived from cryopreserved hepatocytes. In addition, the estimated hepatic clearance value for O⁶-benzylguanine was within ∼80% of the observed total clearance in humans after intravenous administration (15 ml · min⁻¹ · kg⁻¹), indicating a reasonable level of quantitative activity from this in vitro system. However, a 3.5-fold underprediction of total clearance was observed for zaleplon, despite the 5-oxo metabolite being clearly observed. These data taken together suggest that the use of cryopreserved hepatocytes may be a practical approach for assessing AO-mediated metabolism in discovery and potentially useful for predicting hepatic clearance of AO substrates.

  8. Metabolic danger signals, uric acid and ATP, mediate inflammatory cross-talk between hepatocytes and immune cells in alcoholic liver disease.

    PubMed

    Petrasek, Jan; Iracheta-Vellve, Arvin; Saha, Banishree; Satishchandran, Abhishek; Kodys, Karen; Fitzgerald, Katherine A; Kurt-Jones, Evelyn A; Szabo, Gyongyi

    2015-08-01

    Inflammation defines the progression of ALD from reversible to advanced stages. Translocation of bacterial LPS to the liver from the gut is necessary for alcohol-induced liver inflammation. However, it is not known whether endogenous, metabolic danger signals are required for inflammation in ALD. Uric acid and ATP, 2 major proinflammatory danger signals, were evaluated in the serum of human volunteers exposed to a single dose of ethanol or in supernatants of primary human hepatocytes exposed to ethanol. In vitro studies were used to evaluate the role of uric acid and ATP in inflammatory cross-talk between hepatocytes and immune cells. The significance of signaling downstream of uric acid and ATP in the liver was evaluated in NLRP3-deficient mice fed a Lieber-DeCarli ethanol diet. Exposure of healthy human volunteers to a single dose of ethanol resulted in increased serum levels of uric acid and ATP. In vitro, we identified hepatocytes as a significant source of these endogenous inflammatory signals. Uric acid and ATP mediated a paracrine inflammatory cross-talk between damaged hepatocytes and immune cells and significantly increased the expression of LPS-inducible cytokines, IL-1β and TNF-α, by immune cells. Deficiency of NLRP3, a ligand-sensing component of the inflammasome recognizing uric acid and ATP, prevented the development of alcohol-induced liver inflammation in mice and significantly ameliorated liver damage and steatosis. Endogenous metabolic danger signals, uric acid, and ATP are involved in inflammatory cross-talk between hepatocytes and immune cells and play a crucial role in alcohol-induced liver inflammation.

  9. Regression of Copper-Deficient Heart Hypertrophy: Reduction in the Size of Hypertrophic Cardiomyocytes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dietary copper deficiency causes cardiac hypertrophy and its transition to heart failure in a mouse model. Copper repletion results in a rapid regression of cardiac hypertrophy and prevention of heart failure. The present study was undertaken to understand dynamic changes of cardiomyocytes in the hy...

  10. Dose-dependent difference of nuclear receptors involved in murine liver hypertrophy by piperonyl butoxide.

    PubMed

    Sakamoto, Yohei; Yoshida, Midori; Tamura, Kei; Takahashi, Miwa; Kodama, Yukio; Inoue, Kaoru

    2015-12-01

    Nuclear receptors play important roles in chemically induced liver hypertrophy in rodents. To clarify the involvement of constitutive androstane receptor (CAR) and other nuclear receptors in mouse liver hypertrophy induced by different doses of piperonyl butoxide (PBO), wild-type and CAR-knockout mice were administered PBO (200, 1,000, or 5,000 ppm) in the basal diet for 1 week. Increased liver weight and diffuse hepatocellular hypertrophy were observed at 5,000 ppm for both genotypes, accompanied by increased Cyp3a11 mRNA and CYP3A protein expression, suggesting that CAR-independent pathway, possibly pregnane X receptor (PXR), plays a major role in the induction of hypertrophy. Moreover, wild-type mice at 5,000 ppm showed enhanced hepatocellular hypertrophy and strong positive staining for CYP2B in the centrilobular area, suggesting the localized contribution of CAR. At 1,000 ppm, only wild-type mice showed liver weight increase and centrilobular hepatocellular hypertrophy concurrent with elevated Cyp2b10 mRNA expression and strong CYP2B staining, indicating that CAR was essential at 1,000 ppm. We concluded that high-dose PBO induced hypertrophy via CAR and another pathway, while lower dose of PBO induced a pathway mediated predominantly by CAR. The dose-responsiveness on liver hypertrophy is important for understanding the involvement of nuclear receptors.

  11. Inhibition of Receptor Interacting Protein Kinases Attenuates Cardiomyocyte Hypertrophy Induced by Palmitic Acid.

    PubMed

    Zhao, Mingyue; Lu, Lihui; Lei, Song; Chai, Hua; Wu, Siyuan; Tang, Xiaoju; Bao, Qinxue; Chen, Li; Wu, Wenchao; Liu, Xiaojing

    2016-01-01

    Palmitic acid (PA) is known to cause cardiomyocyte dysfunction. Cardiac hypertrophy is one of the important pathological features of PA-induced lipotoxicity, but the mechanism by which PA induces cardiomyocyte hypertrophy is still unclear. Therefore, our study was to test whether necroptosis, a receptor interacting protein kinase 1 and 3 (RIPK1 and RIPK3-) dependent programmed necrosis, was involved in the PA-induced cardiomyocyte hypertrophy. We used the PA-treated primary neonatal rat cardiac myocytes (NCMs) or H9c2 cells to study lipotoxicity. Our results demonstrated that cardiomyocyte hypertrophy was induced by PA treatment, determined by upregulation of hypertrophic marker genes and cell surface area enlargement. Upon PA treatment, the expression of RIPK1 and RIPK3 was increased. Pretreatment with the RIPK1 inhibitor necrostatin-1 (Nec-1), the PA-induced cardiomyocyte hypertrophy, was attenuated. Knockdown of RIPK1 or RIPK3 by siRNA suppressed the PA-induced myocardial hypertrophy. Moreover, a crosstalk between necroptosis and endoplasmic reticulum (ER) stress was observed in PA-treated cardiomyocytes. Inhibition of RIPK1 with Nec-1, phosphorylation level of AKT (Ser473), and mTOR (Ser2481) was significantly reduced in PA-treated cardiomyocytes. In conclusion, RIPKs-dependent necroptosis might be crucial in PA-induced myocardial hypertrophy. Activation of mTOR may mediate the effect of necroptosis in cardiomyocyte hypertrophy induced by PA.

  12. Role of CT Imaging with Volume Reconstruction in Hemi Facial Hypertrophy: A Pediatric Case Report.

    PubMed

    I, Gurubharath; Karanam, Lakshmi Sudha Prasanna; P, Ramesh

    2014-06-01

    Hemifacial hypertrophy is a rare congenital disorder more common in males.It involves the soft tissue, hard bones and teeth of the face.Its etiology is unknown and multiple theories have been postulated. We present a 6-year-old male with hemifacial hypertrophy and describes the importance of CT volume reconstruction in this condition.

  13. New method of turbinate hypertrophy treated by laser

    NASA Astrophysics Data System (ADS)

    Xin, Jiang

    1994-08-01

    Forty-four cases of turbinate hypertrophy are treated by the light fiber insertion of YAG laser, the power density of which is 968 W/cm2. The method consists of the YAG laser irradiation of the anterior area in the turbinate making this membrane pale and then the light fiber is parallely inserted into the inferior turbinate between the membrane and periosteum through the coagulative point. It should be vertically or obliquely inserted in the middle turbinate. The distance between tissues inserted repeatedly is 0.5 cm. The turbinate becomes slightly swollen after operation. The secretion with blood in the nasal cavity increases. The symptoms and signs are relieved in 5 days. Of 44 cases complete recovery was achieved in 28 cases (63.6%); obvious effect was seen in 12 cases (27.3%); improvement in 4 cases (9.1%); and inefficacy in zero. Besides relief of the nasal obstruction the hypersensitive symptoms of the patient with the turbinate hypertrophy resulting from 18 cases of allergic rhinitis are obviously improved. If the operation is not a suitable procedure secondary atrophic rhinitis and turbinate adhesion to the septum may be produced.

  14. A multidimensional proteomic approach to identify hypertrophy-associated proteins.

    PubMed

    Lindsey, Merry L; Goshorn, Danielle K; Comte-Walters, Susana; Hendrick, Jennifer W; Hapke, Elizabeth; Zile, Michael R; Schey, Kevin

    2006-04-01

    Left ventricular hypertrophy (LVH) is a leading cause of congestive heart failure. The exact mechanisms that control cardiac growth and regulate the transition to failure are not fully understood, in part due to the lack of a complete inventory of proteins associated with LVH. We investigated the proteomic basis of LVH using the transverse aortic constriction model of pressure overload in mice coupled with a multidimensional approach to identify known and novel proteins that may be relevant to the development and maintenance of LVH. We identified 123 proteins that were differentially expressed during LVH, including LIM proteins, thioredoxin, myoglobin, fatty acid binding protein 3, the abnormal spindle-like microcephaly protein (ASPM), and cytoskeletal proteins such as actin and myosin. In addition, proteins with unknown functions were identified, providing new directions for future research in this area. We also discuss common pitfalls and strategies to overcome the limitations of current proteomic technologies. Together, the multidimensional approach provides insight into the proteomic changes that occur in the LV during hypertrophy.

  15. Satellite Cells Contribution to Exercise Mediated Muscle Hypertrophy and Repair

    PubMed Central

    Bazgir, Behzad; Fathi, Rouhollah; Rezazadeh Valojerdi, Mojtaba; Mozdziak, Paul; Asgari, Alireza

    2017-01-01

    Satellite cells (SCs) are the most abundant skeletal muscle stem cells. They are widely recognized for their contributions to maintenance of muscle mass, regeneration and hypertrophy during the human life span. These cells are good candidates for cell therapy due to their self-renewal capabilities and presence in an undifferentiated form. Presently, a significant gap exists between our knowledge of SCs behavior and their application as a means for human skeletal muscle tissue repair and regeneration. Both physiological and pathological stimuli potentially affect SCs activation, proliferation, and terminal differentiation the former category being the focus of this article. Activation of SCs occurs following exercise, post-training micro-injuries, and electrical stimulation. Exercise, as a potent and natural stimulus, is at the center of numerous studies on SC activation and relevant fields. According to research, different exercise modalities end with various effects. This review article attempts to picture the state of the art of the SCs life span and their engagement in muscle regeneration and hypertrophy in exercise. PMID:28042532

  16. Trichostatin A accentuates doxorubicin-induced hypertrophy in cardiac myocytes

    PubMed Central

    Karagiannis, Tom C; Lin, Ann JE; Ververis, Katherine; Chang, Lisa; Tang, Michelle M; Okabe, Jun; El-Osta, Assam

    2010-01-01

    Histone deacetylase inhibitors represent a new class of anticancer therapeutics and the expectation is that they will be most effective when used in combination with conventional cancer therapies, such as the anthracycline, doxorubicin. The dose-limiting side effect of doxorubicin is severe cardiotoxicity and evaluation of the effects of combinations of the anthracycline with histone deacetylase inhibitors in relevant models is important. We used a well-established in vitro model of doxorubicin-induced hypertrophy to examine the effects of the prototypical histone deacetylase inhibitor, Trichostatin A. Our findings indicate that doxorubicin modulates the expression of the hypertrophy-associated genes, ventricular myosin light chain-2, the alpha isoform of myosin heavy chain and atrial natriuretic peptide, an effect which is augmented by Trichostatin A. Furthermore, we show that Trichostatin A amplifies doxorubicin-induced DNA double strand breaks, as assessed by γH2AX formation. More generally, our findings highlight the importance of investigating potential side effects that may be associated with emerging combination therapies for cancer. PMID:20930262

  17. Connective tissue growth factor induces cardiac hypertrophy through Akt signaling

    SciTech Connect

    Hayata, Nozomi; Fujio, Yasushi; Yamamoto, Yasuhiro; Iwakura, Tomohiko; Obana, Masanori; Takai, Mika; Mohri, Tomomi; Nonen, Shinpei; Maeda, Makiko; Azuma, Junichi

    2008-05-30

    In the process of cardiac remodeling, connective tissue growth factor (CTGF/CCN2) is secreted from cardiac myocytes. Though CTGF is well known to promote fibroblast proliferation, its pathophysiological effects in cardiac myocytes remain to be elucidated. In this study, we examined the biological effects of CTGF in rat neonatal cardiomyocytes. Cardiac myocytes stimulated with full length CTGF and its C-terminal region peptide showed the increase in cell surface area. Similar to hypertrophic ligands for G-protein coupled receptors, such as endothelin-1, CTGF activated amino acid uptake; however, CTGF-induced hypertrophy is not associated with the increased expression of skeletal actin or BNP, analyzed by Northern-blotting. CTGF treatment activated ERK1/2, p38 MAPK, JNK and Akt. The inhibition of Akt by transducing dominant-negative Akt abrogated CTGF-mediated increase in cell size, while the inhibition of MAP kinases did not affect the cardiac hypertrophy. These findings indicate that CTGF is a novel hypertrophic factor in cardiac myocytes.

  18. Left ventricular hypertrophy: an initial response to myocardial injury.

    PubMed

    Francis, G S; McDonald, K M

    1992-06-04

    The prevailing wisdom generally has been that the failing heart hypertrophies in response to increased wall stress. The increase in myocardial mass observed in heart failure is therefore a relatively late compensatory event geared to normalize wall stress. Although this is undoubtedly true, especially for heart failure resulting from a large anterior myocardial infarction accompanied by rapid left ventricular expansion, it is possible that an important form of hypertrophy occurs much earlier as an initial response to myocardial injury. One can hypothesize that the initial response to injury is a nonspecific phenotypic alteration of the cardiac myocyte to one of growth and development. Such changes may be driven by both trophic and mechanical forces and may be important in altering the architecture of the myocardial cell and surrounding cardiac interstitium. Preliminary data from a variety of models support the concept that neuroendocrine activity is an important component in the ventricular remodeling process, and that pharmacologic interventions designed to block systemic and tissue neuroendocrine activity may prevent excessive cardiac enlargement and its ultimate consequences. Because this concept has important implications for preventive cardiology, the results of several prevention trials, including the Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS), Studies of Left Ventricular Dysfunction (SOLVD), and Survival and Ventricular Enlargement (SAVE) are awaited eagerly.

  19. Skin Sodium Concentration Correlates with Left Ventricular Hypertrophy in CKD.

    PubMed

    Schneider, Markus P; Raff, Ulrike; Kopp, Christoph; Scheppach, Johannes B; Toncar, Sebastian; Wanner, Christoph; Schlieper, Georg; Saritas, Turgay; Floege, Jürgen; Schmid, Matthias; Birukov, Anna; Dahlmann, Anke; Linz, Peter; Janka, Rolf; Uder, Michael; Schmieder, Roland E; Titze, Jens M; Eckardt, Kai-Uwe

    2017-02-02

    The pathogenesis of left ventricular hypertrophy in patients with CKD is incompletely understood. Sodium intake, which is usually assessed by measuring urinary sodium excretion, has been inconsistently linked with left ventricular hypertrophy. However, tissues such as skin and muscle may store sodium. Using (23)sodium-magnetic resonance imaging, a technique recently developed for the assessment of tissue sodium content in humans, we determined skin sodium content at the level of the calf in 99 patients with mild to moderate CKD (42 women; median [range] age, 65 [23-78] years). We also assessed total body overhydration (bioimpedance spectroscopy), 24-hour BP, and left ventricular mass (cardiac magnetic resonance imaging). Skin sodium content, but not total body overhydration, correlated with systolic BP (r=0.33, P=0.002). Moreover, skin sodium content correlated more strongly than total body overhydration did with left ventricular mass (r=0.56, P<0.001 versus r=0.35, P<0.001; P<0.01 between the two correlations). Linear regression analysis demonstrated that skin sodium content is a strong explanatory variable for left ventricular mass, unaffected by BP and total body overhydration. In conclusion, we found skin sodium content to be closely linked to left ventricular mass in patients with CKD. Interventions that reduce skin sodium content might improve cardiovascular outcomes in these patients.

  20. Comparison of rat and hamster hepatocyte primary culture/DNA repair assays

    SciTech Connect

    Kornbrust, D.J.; Barfknect, T.R.

    1984-01-01

    Previous studies have demonstrated marked differences in the capacity of hepatocytes from rats or hamsters to mediate the metabolic activation of chemical carcinogens to genotoxic (i.e., mutagenic) products. Thus far, very few investigations of species differences in DNA repair have been performed. Therefore, a comparison of the relative extent of DNA repair elicited by various genotoxic chemicals in rat and hamster hepatocyes was conducted, using the hepatocyte primary culture/DNA repair (HPC/DR) assay. Of the ll chemicals tested, eight were more potent in inducing DNA repair in hamster hepatocytes than in rat hepatocytes. Dimethylnitrosamine, diethylnitrosamine, 2-acetylaminofluorene, 9-aminoacridine, pararosaniline hydrochloride, 1-naphthylamine, benzidine and 1,2,3,4-diepoxybutane were all active in hamster hepatocytes at a concentration at least ten times less than the lowest effective concentration in rat hepatocytes. The direct-acting alkylating agent, methylmethane sulfonate, was equipotent inducing DNA repair in both rat and hamster hepatocytes, indicating that the differences in DNA repair observed for the other chemicals were probably not a result of species differences in DNA repair capacities. In contrast, 1-nitropyrene produced a greater DNA repair response in rat hepatocyes than hamster hepatocytes, while the bacterial mutagen 3-(chloromethyl)pyridine hydrochloride was inactive in both hepatocyte systems. These studies demonstrate the feasibility of using hamster hepatocytes in the HPC/DR assay and illustrate the utility of performing the assay with hepatocytes from more than one species.

  1. Blood-Compatible Polymer for Hepatocyte Culture with High Hepatocyte-Specific Functions toward Bioartificial Liver Development.

    PubMed

    Hoshiba, Takashi; Otaki, Takayuki; Nemoto, Eri; Maruyama, Hiroka; Tanaka, Masaru

    2015-08-19

    The development of bioartificial liver (BAL) is expected because of the shortage of donor liver for transplantation. The substrates for BAL require the following criteria: (a) blood compatibility, (b) hepatocyte adhesiveness, and (c) the ability to maintain hepatocyte-specific functions. Here, we examined blood-compatible poly(2-methoxyethyl acrylate) (PMEA) and poly(tetrahydrofurfuryl acrylate) (PTHFA) (PTHFA) as the substrates for BAL. HepG2, a human hepatocyte model, could adhere on PMEA and PTHFA substrates. The spreading of HepG2 cells was suppressed on PMEA substrates because integrin contribution to cell adhesion on PMEA substrate was low and integrin signaling was not sufficiently activated. Hepatocyte-specific gene expression in HepG2 cells increased on PMEA substrate, whereas the expression decreased on PTHFA substrates due to the nuclear localization of Yes-associated protein (YAP). These results indicate that blood-compatible PMEA is suitable for BAL substrate. Also, PMEA is expected to be used to regulate cell functions for blood-contacting tissue engineering.

  2. Panmedullary edema with inferior olivary hypertrophy in bilateral medial medullary infarction.

    PubMed

    Inoue, Yasuteru; Miyashita, Fumio; Koga, Masatoshi; Yamada, Naoaki; Toyoda, Kazunori; Minematsu, Kazuo

    2014-03-01

    Bilateral medial medullary infarction (MMI) is a rare type of stroke with poor outcomes. Inferior olivary nucleus hypertrophy results from a pathologic lesion in the Guillain-Mollaret triangle. The relationship between inferior olivary nucleus hypertrophy and the medullary lesion is obscure. To the best of our knowledge, only 1 autopsy case with unilateral medial medullary infarction that was associated with ipsilateral inferior olivary nucleus hypertrophy has been reported. We describe a rare case with acute infarction in the bilateral medial medulla oblongata accompanied by subacute bilateral inferior olivary nucleus hypertrophy and panmedullary edema. The hypertrophy appeared to have been caused by local ischemic damage to the termination of the central tegmental tract at the bilateral inferior olivary nucleus.

  3. Molecular switches under TGFβ signalling during progression from cardiac hypertrophy to heart failure.

    PubMed

    Heger, J; Schulz, R; Euler, G

    2016-01-01

    Cardiac hypertrophy is a mechanism to compensate for increased cardiac work load, that is, after myocardial infarction or upon pressure overload. However, in the long run cardiac hypertrophy is a prevailing risk factor for the development of heart failure. During pathological remodelling processes leading to heart failure, decompensated hypertrophy, death of cardiomyocytes by apoptosis or necroptosis and fibrosis as well as a progressive dysfunction of cardiomyocytes are apparent. Interestingly, the induction of hypertrophy, cell death or fibrosis is mediated by similar signalling pathways. Therefore, tiny changes in the signalling cascade are able to switch physiological cardiac remodelling to the development of heart failure. In the present review, we will describe examples of these molecular switches that change compensated hypertrophy to the development of heart failure and will focus on the importance of the signalling cascades of the TGFβ superfamily in this process. In this context, potential therapeutic targets for pharmacological interventions that could attenuate the progression of heart failure will be discussed.

  4. Gender differences in methionine accumulation and metabolism in freshly isolated mouse hepatocytes: Potential roles in toxicity

    SciTech Connect

    Dever, Joseph T.; Elfarra, Adnan A.

    2009-05-01

    L-Methionine (Met) is hepatotoxic at high concentrations. Because Met toxicity in freshly isolated mouse hepatocytes is gender-dependent, the goal of this study was to assess the roles of Met accumulation and metabolism in the increased sensitivity of male hepatocytes to Met toxicity compared with female hepatocytes. Male hepatocytes incubated with Met (30 mM) at 37 {sup o}C exhibited higher levels of intracellular Met at 0.5, 1.0, and 1.5 h, respectively, compared to female hepatocytes. Conversely, female hepatocytes had higher levels of S-adenosyl-L-methionine compared to male hepatocytes. Female hepatocytes also exhibited higher L-methionine-L-sulfoxide levels relative to control hepatocytes, whereas the increases in L-methionine-D-sulfoxide (Met-D-O) levels were similar in hepatocytes of both genders. Addition of aminooxyacetic acid (AOAA), an inhibitor of Met transamination, significantly increased Met levels at 1.5 h and increased Met-D-O levels at 1.0 and 1.5 h only in Met-exposed male hepatocytes. No gender differences in cytosolic Met transamination activity by glutamine transaminase K were detected. However, female mouse liver cytosol exhibited higher methionine-DL-sulfoxide (MetO) reductase activity than male mouse liver cytosol at low (0.25 and 0.5 mM) MetO concentrations. Collectively, these results suggest that increased cellular Met accumulation, decreased Met transmethylation, and increased Met and MetO transamination in male mouse hepatocytes may be contributing to the higher sensitivity of the male mouse hepatocytes to Met toxicity in comparison with female mouse hepatocytes.

  5. Gender differences in methionine accumulation and metabolism in freshly isolated mouse hepatocytes: potential roles in toxicity.

    PubMed

    Dever, Joseph T; Elfarra, Adnan A

    2009-05-01

    L-methionine (Met) is hepatotoxic at high concentrations. Because Met toxicity in freshly isolated mouse hepatocytes is gender-dependent, the goal of this study was to assess the roles of Met accumulation and metabolism in the increased sensitivity of male hepatocytes to Met toxicity compared with female hepatocytes. Male hepatocytes incubated with Met (30 mM) at 37 degrees C exhibited higher levels of intracellular Met at 0.5, 1.0, and 1.5 h, respectively, compared to female hepatocytes. Conversely, female hepatocytes had higher levels of S-adenosyl-L-methionine compared to male hepatocytes. Female hepatocytes also exhibited higher L-methionine-L-sulfoxide levels relative to control hepatocytes, whereas the increases in L-methionine-D-sulfoxide (Met-D-O) levels were similar in hepatocytes of both genders. Addition of aminooxyacetic acid (AOAA), an inhibitor of Met transamination, significantly increased Met levels at 1.5 h and increased Met-d-O levels at 1.0 and 1.5 h only in Met-exposed male hepatocytes. No gender differences in cytosolic Met transamination activity by glutamine transaminase K were detected. However, female mouse liver cytosol exhibited higher methionine-dl-sulfoxide (MetO) reductase activity than male mouse liver cytosol at low (0.25 and 0.5 mM) MetO concentrations. Collectively, these results suggest that increased cellular Met accumulation, decreased Met transmethylation, and increased Met and MetO transamination in male mouse hepatocytes may be contributing to the higher sensitivity of the male mouse hepatocytes to Met toxicity in comparison with female mouse hepatocytes.

  6. Puerarin ameliorates hepatic steatosis by activating the PPARα and AMPK signaling pathways in hepatocytes.

    PubMed

    Kang, Ok-Hwa; Kim, Sung-Bae; Mun, Su-Hyun; Seo, Yun-Soo; Hwang, Hyeong-Chil; Lee, Young-Mi; Lee, Ho-Seob; Kang, Dae-Gil; Kwon, Dong-Yeul

    2015-03-01

    Non-alcoholic fatty liver disease (NAFLD) is characterized by the hepatic manifestation of metabolic syndrome and is the leading cause of chronic liver disease. Steatohepatitis plays a critical role in the process resulting in liver fibrosis and cirrhosis. Puerarin is a herbal product widely used in Asia, and is believed to have therapeutic benefits for alleviating the symptoms of steatohepatitis. The present study was designed to investigate the effects and mechanisms of action of puerarin in reducing lipid accumulation in oleic acid (OA)-treated HepG2 cells. Hepatocytes were treated with OA with or without puerarin to observe lipid accumulation by Oil Red O staining. We also examined hepatic lipid contents (e.g., triacylglycerol and cholesterol) following treatment with puerarin. Western blot analysis and reverse transcription-polymerase chain reaction (RT-PCR) were used to measure sterol regulatory element binding protein (SREBP)-1, fatty acid synthase (FAS), peroxisome proliferator-activated receptor α (PPARα) and adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) protein and mRNA expression, respectively. Our results revealed that puerarin suppressed OA-induced lipid accumulation, and reduced the triacylglycerol and cholesterol levels. Furthermore, puerarin decreased the expression levels of lipogenic enzymes, such as FAS and SREBPs, and increased the expression levels of PPARα, which are critical regulators of hepatic lipid metabolism through the AMPK signaling pathway. These results indicate that puerarin has the same ability to activate AMPK, and reduce SREBP-1 and FAS expression, thus inhibiting hepatic lipogenesis and increasing hepatic antioxidant activity. We found that puerarin exerted a regulatory effect on lipid accumulation by decreasing lipogenesis in hepatocytes. Therefore, puerarin extract may have therapeutic benefits in the treatment of fatty liver and lipid-related metabolic disorders.

  7. Inverse zonation of hepatocyte transduction with AAV vectors between mice and non-human primates

    PubMed Central

    Bell, Peter; Wang, Lili; Gao, Guangping; Haskins, Mark E.; Tarantal, Alice F.; McCarter, Robert J.; Zhu, Yanqing; Yu, Hongwei; Wilson, James M.

    2011-01-01

    Gene transfer vectors based on adeno-associated virus 8 (AAV8) are highly efficient in liver transduction and can be easily administered by intravenous injection. In mice, AAV8 transduces predominantly hepatocytes near central veins and yields lower transduction levels in hepatocytes in periportal regions. This transduction bias has important implications for gene therapy that aims to correct metabolic liver enzymes because metabolic zonation along the porto-central axis requires the expression of therapeutic proteins within the zone where they are normally localized. In the present study we compared the expression pattern of AAV8 expressing green fluorescent protein (GFP) in liver between mice, dogs, and non-human primates. We confirmed the pericentral dominance in transgene expression in mice with AAV8 when the liver-specific thyroid hormone-binding globulin (TBG) promoter was used but also observed the same expression pattern with the ubiquitous chicken β-actin (CB) and cytomegalovirus (CMV) promoters, suggesting that transduction zonation is not caused by promoter specificity. Predominantly pericentral expression was also found in dogs injected with AAV8. In contrast, in cynomolgus and rhesus macaques the expression pattern from AAV vectors was reversed, i.e. transgene expression was most intense around portal areas and less intense or absent around central veins. Infant rhesus macaques as well as newborn mice injected with AAV8 however showed a random distribution of transgene expression with neither portal nor central transduction bias. Based on the data in monkeys, adult humans treated with AAV vectors are predicted to also express transgenes predominantly in periportal regions whereas infants are likely to show a uniform transduction pattern in liver. PMID:21778099

  8. Global microRNA profiles and signaling pathways in the development of cardiac hypertrophy

    PubMed Central

    Feng, H.J.; Ouyang, W.; Liu, J.H.; Sun, Y.G.; Hu, R.; Huang, L.H.; Xian, J.L.; Jing, C.F.; Zhou, M.J.

    2014-01-01

    Hypertrophy is a major predictor of progressive heart disease and has an adverse prognosis. MicroRNAs (miRNAs) that accumulate during the course of cardiac hypertrophy may participate in the process. However, the nature of any interaction between a hypertrophy-specific signaling pathway and aberrant expression of miRNAs remains unclear. In this study, Spague Dawley male rats were treated with transverse aortic constriction (TAC) surgery to mimic pathological hypertrophy. Hearts were isolated from TAC and sham operated rats (n=5 for each group at 5, 10, 15, and 20 days after surgery) for miRNA microarray assay. The miRNAs dysexpressed during hypertrophy were further analyzed using a combination of bioinformatics algorithms in order to predict possible targets. Increased expression of the target genes identified in diverse signaling pathways was also analyzed. Two sets of miRNAs were identified, showing different expression patterns during hypertrophy. Bioinformatics analysis suggested the miRNAs may regulate multiple hypertrophy-specific signaling pathways by targeting the member genes and the interaction of miRNA and mRNA might form a network that leads to cardiac hypertrophy. In addition, the multifold changes in several miRNAs suggested that upregulation of rno-miR-331*, rno-miR-3596b, rno-miR-3557-5p and downregulation of rno-miR-10a, miR-221, miR-190, miR-451 could be seen as biomarkers of prognosis in clinical therapy of heart failure. This study described, for the first time, a potential mechanism of cardiac hypertrophy involving multiple signaling pathways that control up- and downregulation of miRNAs. It represents a first step in the systematic discovery of miRNA function in cardiovascular hypertrophy. PMID:24728214

  9. BMP type I receptor ALK2 is required for angiotensin II-induced cardiac hypertrophy.

    PubMed

    Shahid, Mohd; Spagnolli, Ester; Ernande, Laura; Thoonen, Robrecht; Kolodziej, Starsha A; Leyton, Patricio A; Cheng, Juan; Tainsh, Robert E T; Mayeur, Claire; Rhee, David K; Wu, Mei X; Scherrer-Crosbie, Marielle; Buys, Emmanuel S; Zapol, Warren M; Bloch, Kenneth D; Bloch, Donald B

    2016-04-15

    Bone morphogenetic protein (BMP) signaling contributes to the development of cardiac hypertrophy. However, the identity of the BMP type I receptor involved in cardiac hypertrophy and the underlying molecular mechanisms are poorly understood. By using quantitative PCR and immunoblotting, we demonstrated that BMP signaling increased during phenylephrine-induced hypertrophy in cultured neonatal rat cardiomyocytes (NRCs), as evidenced by increased phosphorylation of Smads 1 and 5 and induction of Id1 gene expression. Inhibition of BMP signaling with LDN193189 or noggin, and silencing of Smad 1 or 4 using small interfering RNA diminished the ability of phenylephrine to induce hypertrophy in NRCs. Conversely, activation of BMP signaling with BMP2 or BMP4 induced hypertrophy in NRCs. Luciferase reporter assay further showed that BMP2 or BMP4 treatment of NRCs repressed atrogin-1 gene expression concomitant with an increase in calcineurin protein levels and enhanced activity of nuclear factor of activated T cells, providing a mechanism by which BMP signaling contributes to cardiac hypertrophy. In a model of cardiac hypertrophy, C57BL/6 mice treated with angiotensin II (A2) had increased BMP signaling in the left ventricle. Treatment with LDN193189 attenuated A2-induced cardiac hypertrophy and collagen deposition in left ventricles. Cardiomyocyte-specific deletion of BMP type I receptor ALK2 (activin-like kinase 2), but not ALK1 or ALK3, inhibited BMP signaling and mitigated A2-induced cardiac hypertrophy and left ventricular fibrosis in mice. The results suggest that BMP signaling upregulates the calcineurin/nuclear factor of activated T cell pathway via BMP type I receptor ALK2, contributing to cardiac hypertrophy and fibrosis.

  10. Mechanisms of nascent fiber formation during avian skeletal muscle hypertrophy

    NASA Technical Reports Server (NTRS)

    McCormick, K. M.; Schultz, E.

    1992-01-01

    This study examined two putative mechanisms of new fiber formation in postnatal skeletal muscle, namely longitudinal fragmentation of existing fibers and de novo formation. The relative contributions of these two mechanisms to fiber formation in hypertrophying anterior latissimus dorsi (ALD) muscle were assessed by quantitative analysis of their nuclear populations. Muscle hypertrophy was induced by wing-weighting for 1 week. All nuclei formed during the weighting period were labeled by continuous infusion of 5-bromo-2'-deoxyuridine (BrdU), a thymidine analog, and embryonic-like fibers were identified using an antibody to ventricular-like embryonic (V-EMB) myosin. The number of BrdU-labeled and unlabeled nuclei in V-EMB-positive fibers were counted. Wing-weighting resulted in significant muscle enlargement and the appearance of many V-EMB+ fibers. The majority of V-EMB+ fibers were completely independent of mature fibers and had a nuclear density characteristics of developing fibers. Furthermore, nearly 100% of the nuclei in independent V-EMB+ fibers were labeled. These findings strongly suggest that most V-EMB+ fibers were nascent fibers formed de novo during the weighting period by satellite cell activation and fusion. Nascent fibers were found primarily in the space between fascicles where they formed a complex anastomosing network of fibers running at angles to one another. Although wing-weighting induced an increase in the number of branched fibers, there was no evidence that V-EMB+ fibers were formed by longitudinal fragmentation. The location of newly formed fibers in wing-weighted and regenerating ALD muscle was compared to determine whether satellite cells in the ALD muscle were unusual in that, if stimulated to divide, they would form fibers in the inter- and intrafascicular space. In contrast to wing-weighted muscle, nascent fibers were always found closely associated with necrotic fibers. These results suggest that wing-weighting is not simply another

  11. [An experimental study on the protective effect of hepatocyte growth factor (HGF) for the primary cultured hepatocytes obtained from iron-loaded rats].

    PubMed

    Yoshida, J

    1995-01-01

    Pathological iron deposition in liver is often found in various liver diseases. The deposited iron is thought to be one of the most important factor of liver cell injury, not only in hemochromotosis but also in cirrhosis following hepatitis virus B or C infection. To investigate the influence of the deposited iron on damage and regeneration of hepatocyte, primary cultured hepatocytes obtained from carbonyl iron-loaded rats were treated with carbon tetrachloride (CCl4) in the presence or absence of hepatocyte growth factor (HGF). Although the section of liver from carbonyl iron-loaded rats showed no necrosis and fibrosis, iron-loaded hepatocytes contained about twofold more iron than control. The damage of iron-loaded hepatocytes induced by CCl4 was more serious than that of control, and HGF decreased this injury only in iron-loaded hepatocytes but not in control. There is no difference in DNA synthesis stimulated by HGF between iron-loaded hepatocytes and control. These findings suggest that the pathological iron deposition induces the fragility of hepatocyte and that cytoprotective effect of HGF is induced by this pathological iron.

  12. Liver tissue engineering utilizing hepatocytes propagated in mouse livers in vivo.

    PubMed

    Ohashi, Kazuo; Tatsumi, Kohei; Tateno, Chise; Kataoka, Miho; Utoh, Rie; Yoshizato, Katsutoshi; Okano, Teruo

    2012-01-01

    Recent advances in tissue engineering technologies have highlighted the ability to create functional liver systems using isolated hepatocytes in vivo. Considering the serious shortage of donor livers that can be used for hepatocyte isolation, it has remained imperative to establish a hepatocyte propagation protocol to provide highly efficient cell recovery allowing for subsequent tissue engineering procedures. Donor primary hepatocytes were isolated from human α-1 antitrypsin (hA1AT) transgenic mice and were transplanted into the recipient liver of urokinase-type plasminogen activator-severe combined immunodeficiency (uPA/SCID) mice. Transplanted donor hepatocytes actively proliferated within the recipient liver of the uPA/SCID mice. At week 8 or later, full repopulation of the uPA/SCID livers with the transplanted hA1AT hepatocytes were confirmed by blood examination and histological assessment. Proliferated hA1AT hepatocytes were recovered from the recipient uPA/SCID mice, and we generated hepatocyte sheets using these recovered hepatocytes for subsequent transplantation into the subcutaneous space of mice. Stable persistency of the subcutaneously engineered liver tissues was confirmed for up to 90 days, which was the length of our present study. These new data demonstrate the feasibility in propagating murine hepatocytes prior to the development of hepatic cells and bioengineered liver systems. The ability to regenerate and expand hepatocytes has potential clinical value whereby procurement of small amounts of tissue could be expanded to sufficient quantities prior to their use in hepatocyte transplantation or other hepatocyte-based therapies.

  13. Transcriptional activation of ribosomal RNA genes during compensatory renal hypertrophy

    SciTech Connect

    Ouellette, A.J.; Moonka, R.; Zelenetz, A.; Malt, R.A.

    1986-05-01

    The overall rate of rDNA transcription increases by 50% during the first 24 hours of compensatory renal hypertrophy in the mouse. To study mechanisms of ribosome accumulation after uninephrectomy, transcription rates were measured in isolated kidneys by transcriptional runoff. /sup 32/P-labeled nascent transcripts were hybridized to blots containing linearized, denatured cloned rDNA, and hybridization was quantitated autoradiographically and by direct counting. Overall transcriptional activity of rDNA was increased by 30% above control levels at 6 hrs after nephrectomy and by 50% at 12, 18, and 24 hrs after operation. Hybridizing RNA was insensitive to inhibiby alpha-amanitin, and no hybridization was detected to vector DNA. Thus, accelerated rDNA transcription is one regulatory element in the accretion of ribosomes in renal growth, and the regulatory event is an early event. Mechanisms of activation may include enhanced transcription of active genes or induction of inactive DNA.

  14. AKAP-Lbc mobilizes a cardiac hypertrophy signaling pathway.

    PubMed

    Carnegie, Graeme K; Soughayer, Joseph; Smith, F Donelson; Pedroja, Benjamin S; Zhang, Fang; Diviani, Dario; Bristow, Michael R; Kunkel, Maya T; Newton, Alexandra C; Langeberg, Lorene K; Scott, John D

    2008-10-24

    Elevated catecholamines in the heart evoke transcriptional activation of the Myocyte Enhancer Factor (MEF) pathway to induce a cellular response known as pathological myocardial hypertrophy. We have discovered that the A-Kinase Anchoring Protein (AKAP)-Lbc is upregulated in hypertrophic cardiomyocytes. It coordinates activation and movement of signaling proteins that initiate MEF2-mediated transcriptional reprogramming events. Live-cell imaging, fluorescent kinase activity reporters, and RNA interference techniques show that AKAP-Lbc couples activation of protein kinase D (PKD) with the phosphorylation-dependent nuclear export of the class II histone deacetylase HDAC5. These studies uncover a role for AKAP-Lbc in which increased expression of the anchoring protein selectively amplifies a signaling pathway that drives cardiac myocytes toward a pathophysiological outcome.

  15. Syringomyelia, limb hypertrophy and sympathetic overactivity: a rare association

    PubMed Central

    Khanra, Dibbendhu; Ray, Sayantan; Sonthalia, Nikhil; Talukdar, Arunansu

    2012-01-01

    A 32-year-old man presented with uniform enlargement of right upper limb for 6 years. Examination revealed painful disorganised elbow joint along with sensory impairment in the affected limb with weakness of small muscles. The patient was given empirical antileprotic therapy from outside without any benefit. Ultrasonography showed pan-hypertrophic nature of local tissues. Although axonal type of sensorimotor neuropathy involving right ulnar and median nerve was detected in nerve conduction velocity study, biopsy of the same failed to confirm any axonal degeneration or evidence of leprosy. Considering the nature of sensory abnormality MRI of cervical spine was done which revealed a syrinx extending from C3 till D2. Tests for vasomotor tone showed positive results on the affected limb. Syringomyelia can rarely give rise to pan-hypertrophy of limb due to sympathetic overactivity, which is infrequently reported in literatures and deficient in logical grounds. PMID:22707684

  16. Exercise and the Regulation of Skeletal Muscle Hypertrophy.

    PubMed

    McGlory, Chris; Phillips, Stuart M

    2015-01-01

    Skeletal muscle is a critical organ serving as the primary site for postprandial glucose disposal and the generation of contractile force. The size of human skeletal muscle mass is dependent upon the temporal relationship between changes in muscle protein synthesis (MPS) and muscle protein breakdown. The aim of this chapter is to review our current understanding of how resistance exercise influences protein turnover with a specific emphasis on the molecular factors regulating MPS. We also will discuss recent data relating to the prescription of resistance exercise to maximize skeletal muscle hypertrophy. Finally, we evaluate the impact of age and periods of disuse on the loss of muscle mass and the controversy surround the etiology of muscle disuse atrophy.

  17. mTOR Inhibition and Cardiovascular Diseases: Cardiac Hypertrophy.

    PubMed

    Paoletti, Ernesto

    2017-02-23

    Left ventricular hypertrophy (LVH) is highly prevalent in kidney transplant recipients, and is associated with poor clinical outcome. Immunosuppressive agents might affect LVH behavior after kidney transplantation. This review is an appraisal of available data regarding LVH in renal transplantation and especially of studies that evaluated LVH response to treatment. In particular, the role of mammalian target of rapamycin inhibitors adopted as immunosuppressive agents in kidney transplantation is reviewed in the light of recent studies that have shown LVH regression induced by this class of medications in kidney transplant recipients with posttransplant cardiomyopathy. Larger randomized controlled trials are warranted in order to confirm these findings and to ascertain the impact of such LVH regression on hard endpoints in kidney transplant recipients with posttransplant cardiomyopathy.

  18. Intensive Hemodialysis, Left Ventricular Hypertrophy, and Cardiovascular Disease.

    PubMed

    McCullough, Peter A; Chan, Christopher T; Weinhandl, Eric D; Burkart, John M; Bakris, George L

    2016-11-01

    The prevalence of cardiovascular disease, including cardiac arrhythmia, coronary artery disease, cardiomyopathy, and valvular heart disease, is higher in hemodialysis (HD) patients than in the US resident population. Cardiovascular disease is the leading cause of death in HD patients and the principal discharge diagnosis accompanying 1 in 4 hospital admissions. Furthermore, the rate of hospital admissions for either heart failure or fluid overload is persistently high despite widespread use of β-blockers and renin-angiotensin system inhibitors and attempts to manage fluid overload with ultrafiltration. An important predictor of cardiovascular mortality and morbidity in dialysis patients is left ventricular hypertrophy (LVH). LVH is an adaptive response to increased cardiac work, typically caused by combined pressure and volume overload, resulting in cardiomyocyte hypertrophy and increased intercellular matrix. In new dialysis patients, the prevalence of LVH is 75%. Regression of LVH may reduce cardiovascular risk, including the incidence of heart failure, complications after myocardial infarction, and sudden arrhythmic death. Multiple randomized clinical trials show that intensive HD reduces left ventricular mass, a measure of LVH. Short daily and nocturnal schedules in the Frequent Hemodialysis Network trial reduced left ventricular mass by 14 (10%) and 11 (8%) g, respectively, relative to 3 sessions per week. Comparable efficacy was observed in an earlier trial of nocturnal HD. Intensive HD also improves cardiac rhythm. Clinical benefits have been reported only in observational studies. Daily home HD is associated with 17% and 16% lower risks for cardiovascular death and hospitalization, respectively; admissions for cerebrovascular disease, heart failure, and hypertensive disease, which collectively constitute around half of cardiovascular hospitalizations, were less likely with daily home HD. Relative to peritoneal dialysis, daily home HD is likewise associated

  19. Klotho Protects Against Indoxyl Sulphate-Induced Myocardial Hypertrophy

    PubMed Central

    Yang, Ke; Wang, Cheng; Nie, Ling; Zhao, Xiaohui; Gu, Jun; Guan, Xu; Wang, Song; Xiao, Tangli; Xu, Xinli; He, Ting; Xia, Xuefeng

    2015-01-01

    Left ventricular hypertrophy (LVH) is a common complication in patients with CKD and an independent risk factor for death. Changes in the levels of uremic solutes or Klotho have been reported to be related to CKD, whereas the relationships between these factors and CKD-associated LVH remain unclear. Here, we investigated the interaction between Klotho and indoxyl sulfate (IS), a typical uremic solute, in CKD-associated LVH. In a survey of 86 patients with CKD, a negative relationship was found between serum levels of IS and Klotho (r=−0.59, P<0.001). Furthermore, serum levels of IS and Klotho were independently associated with LVH (for IS: r=0.69, P<0.001; for Klotho: r=−0.49, P<0.001). In normal mice, intraperitoneal injection of IS for 8 weeks induced LVH accompanied by substantial downregulation of renal Klotho. Notably, IS-induced LVH was more severe in heterozygous Klotho-deficient (kl/+) mice. In vitro, treatment with Klotho strongly inhibited IS-induced cardiomyocyte hypertrophy by blocking oxidative stress and inhibiting p38 and extracellular signal–regulated protein kinase 1/2 signaling pathways. In a mouse model of CKD-associated LVH, the renal expression of Klotho was lower and the level of serum IS was higher than in healthy controls. Moreover, treatment of CKD mice with Klotho protein significantly restrained the development of LVH. Taken together, these results suggest that Klotho is an endogenous protector against IS-induced LVH, and the imbalance between Klotho and IS may contribute to the development of LVH in CKD. PMID:25804281

  20. Reversible Thermoset Adhesives

    NASA Technical Reports Server (NTRS)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  1. Insulin-induced CARM1 upregulation facilitates hepatocyte proliferation

    SciTech Connect

    Yeom, Chul-gon; Kim, Dong-il; Park, Min-jung; Choi, Joo-hee; Jeong, Jieun; Wi, Anjin; Park, Whoashig; Han, Ho-jae; Park, Soo-hyun

    2015-06-05

    Previously, we reported that CARM1 undergoes ubiquitination-dependent degradation in renal podocytes. It was also reported that CARM1 is necessary for fasting-induced hepatic gluconeogenesis. Based on these reports, we hypothesized that treatment with insulin, a hormone typically present under the ‘fed’ condition, would inhibit gluconeogenesis via CARM1 degradation. HepG2 cells, AML-12 cells, and rat primary hepatocytes were treated with insulin to confirm CARM1 downregulation. Surprisingly, insulin treatment increased CARM1 expression in all cell types examined. Furthermore, treatment with insulin increased histone 3 methylation at arginine 17 and 26 in HepG2 cells. To elucidate the role of insulin-induced CARM1 upregulation, the HA-CARM1 plasmid was transfected into HepG2 cells. CARM1 overexpression did not increase the expression of lipogenic proteins generally increased by insulin signaling. Moreover, CARM1 knockdown did not influence insulin sensitivity. Insulin is known to facilitate hepatic proliferation. Like insulin, CARM1 overexpression increased CDK2 and CDK4 expression. In addition, CARM1 knockdown reduced the number of insulin-induced G2/M phase cells. Moreover, GFP-CARM1 overexpression increased the number of G2/M phase cells. Based on these results, we concluded that insulin-induced CARM1 upregulation facilitates hepatocyte proliferation. These observations indicate that CARM1 plays an important role in liver pathophysiology. - Highlights: • Insulin treatment increases CARM1 expression in hepatocytes. • CARM1 overexpression does not increase the expression of lipogenic proteins. • CARM1 knockdown does not influence insulin sensitivity. • Insulin-induced CARM1 upregulation facilitates hepatocyte proliferation.

  2. ER stress induces NLRP3 inflammasome activation and hepatocyte death

    PubMed Central

    Lebeaupin, C; Proics, E; de Bieville, C H D; Rousseau, D; Bonnafous, S; Patouraux, S; Adam, G; Lavallard, V J; Rovere, C; Le Thuc, O; Saint-Paul, M C; Anty, R; Schneck, A S; Iannelli, A; Gugenheim, J; Tran, A; Gual, P; Bailly-Maitre, B

    2015-01-01

    The incidence of chronic liver disease is constantly increasing, owing to the obesity epidemic. However, the causes and mechanisms of inflammation-mediated liver damage remain poorly understood. Endoplasmic reticulum (ER) stress is an initiator of cell death and inflammatory mechanisms. Although obesity induces ER stress, the interplay between hepatic ER stress, NLRP3 inflammasome activation and hepatocyte death signaling has not yet been explored during the etiology of chronic liver diseases. Steatosis is a common disorder affecting obese patients; moreover, 25% of these patients develop steatohepatitis with an inherent risk for progression to hepatocarcinoma. Increased plasma LPS levels have been detected in the serum of patients with steatohepatitis. We hypothesized that, as a consequence of increased plasma LPS, ER stress could be induced and lead to NLRP3 inflammasome activation and hepatocyte death associated with steatohepatitis progression. In livers from obese mice, administration of LPS or tunicamycin results in IRE1α and PERK activation, leading to the overexpression of CHOP. This, in turn, activates the NLRP3 inflammasome, subsequently initiating hepatocyte pyroptosis (caspase-1, -11, interleukin-1β secretion) and apoptosis (caspase-3, BH3-only proteins). In contrast, the LPS challenge is blocked by the ER stress inhibitor TUDCA, resulting in: CHOP downregulation, reduced caspase-1, caspase-11, caspase-3 activities, lowered interleukin-1β secretion and rescue from cell death. The central role of CHOP in mediating the activation of proinflammatory caspases and cell death was characterized by performing knockdown experiments in primary mouse hepatocytes. Finally, the analysis of human steatohepatitis liver biopsies showed a correlation between the upregulation of inflammasome and ER stress markers, as well as liver injury. We demonstrate here that ER stress leads to hepatic NLRP3 inflammasome pyroptotic death, thus contributing as a novel mechanism of

  3. Bioactivation of fluorotelomer alcohols in isolated rat hepatocytes.

    PubMed

    Martin, Jonathan W; Chan, Katie; Mabury, Scott A; O'Brien, Peter J

    2009-02-12

    Fluorotelomer alcohols (FTOHs; C(x)F(2x+1)C(2)H(4)OH) are intermediates in the production of specialty surfactants and stain-repellent polymers. The magnitude and pathways of human exposure to FTOHs are not understood, but FTOHs are present in ambient air and house dust, and FTOH-derivatives are used in food-contact applications. Previously, electrophilic FTOH biotransformation products were detected in rat hepatocytes, and liver lesions were found in FTOH exposed rodents. To begin elucidating the mechanism(s) of action, freshly isolated rat hepatocytes were incubated with FTOHs, or FTOH biotransformation products, and toxicity was followed in the presence or absence of carbonyl scavengers and metabolic enzyme modulators. The LC(50) depended on perfluorinated chain length, with the shortest (4:2 FTOH; x=4) and longest (8:2 FTOH; x=8) FTOHs tested being more toxic than the medium chain length FTOH (6:2 FTOH; x=6); a structure-toxicity relationship that is consistent with that for 2-alkenals. For hepatocytes treated with 8:2 FTOH, cytotoxicity corresponded to depletion of glutathione (GSH), increased protein carbonylation, and lipid peroxidation. Aminobenzotriazole, a P450 inhibitor, diminished cytotoxicity for all FTOHs tested, and decreased protein carbonylation and lipid peroxidation for 8:2 FTOH, indicating that a biotransformation product was responsible for FTOH cytotoxicity. Preincubation of hepatocytes with hydralazine or aminoguanidine decreased the cytotoxicity of 8:2 FTOH, suggesting that reactive aldehyde intermediates contributed to the cytotoxicity. A GSH-reactive alpha/beta-unsaturated acid metabolite was also more toxic than the corresponding FTOH, and may have contributed to the observed effects. Overall, these results suggested that FTOH toxicity was related to electrophilic aldehydes or acids through GSH depletion and protein carbonylation. Further research into the nature of protein modification is warranted for these current-use fluorochemicals.

  4. MicroRNA-497 Inhibits Cardiac Hypertrophy by Targeting Sirt4

    PubMed Central

    Xiao, Yimin; Zhang, Xiaofei; Fan, Shihao; Cui, Guanghao; Shen, Zhenya

    2016-01-01

    Cardiac hypertrophy is an adaptive enlargement of the myocardium in response to overload pressure of heart. From abundant studies, a conclusion is drawn that many microRNAs (miRNAs) are associated with cardiac hypertrophy and heart failure. To investigate the role of microRNA-497 (miR-497) in myocardial hypertrophy, two models were established in this study from cell level to integral level. Cardiac hypertrophy was induced by using angiotensin Ⅱ (Ang Ⅱ) in vitro and was created by transverse abdominal aortic constriction (TAC) in vivo. There was a significant decrease expression of miR-497 in cardiac hypertrophy models. Moreover, overexpression of miR-497 inhibited myocardial hypertrophy both in vitro and in vivo without heart function variation. In addition, luciferase reporter assays demonstrated that Sirt4 was a direct target gene of miR-497. Taking together, our study indicates that miR-497 modulates cardiac hypertrophy by targeting Sirt4 and may serve as a potential therapeutic substance in the course. PMID:27992564

  5. Disruption of ROCK1 gene attenuates cardiac dilation and improves contractile function in pathological cardiac hypertrophy.

    PubMed

    Shi, Jianjian; Zhang, Yi-Wei; Summers, Lelia J; Dorn, Gerald W; Wei, Lei

    2008-03-01

    The development of left ventricular cardiomyocyte hypertrophy in response to increased hemodynamic load and neurohormonal stress is initially a compensatory response. However, persistent stress eventually leads to dilated heart failure, which is a common cause of heart failure in human hypertensive and valvular heart disease. We have recently reported that Rho-associated coiled-coil containing protein kinase 1 (ROCK1) homozygous knockout mice exhibited reduced cardiac fibrosis and cardiomyocyte apoptosis, while displaying a preserved compensatory hypertrophic response to pressure overload. In this study, we have tested the effects of ROCK1 deficiency on cardiac hypertrophy, dilation, and dysfunction. We have shown that ROCK1 deletion attenuated left ventricular dilation and contractile dysfunction, but not hypertrophy, in a transgenic model of Galphaq overexpression-induced hypertrophy which represents a well-characterized and highly relevant genetic mouse model of pathological hypertrophy. Although the development of cardiomyocyte hypertrophy was not affected, ROCK1 deletion in Galphaq mice resulted in a concentric hypertrophic phenotype associated with reduced induction of hypertrophic markers indicating that ROCK1 deletion could favorably modify hypertrophy without inhibiting it. Furthermore, ROCK1 deletion also improved contractile response to beta-adrenergic stimulation in Galphaq transgenic mice. Consistent with this observation, ROCK1 deletion prevented down-regulation of type V/VI adenylyl cyclase expression, which is associated with the impaired beta-adrenergic signaling in Galphaq mice. The present study establishes for the first time a role for ROCK1 in cardiac dilation and contractile dysfunction.

  6. Tumor necrosis factor receptor-associated factor 3 is a positive regulator of pathological cardiac hypertrophy.

    PubMed

    Jiang, Xi; Deng, Ke-Qiong; Luo, Yuxuan; Jiang, Ding-Sheng; Gao, Lu; Zhang, Xiao-Fei; Zhang, Peng; Zhao, Guang-Nian; Zhu, Xueyong; Li, Hongliang

    2015-08-01

    Cardiac hypertrophy, a common early symptom of heart failure, is regulated by numerous signaling pathways. Here, we identified tumor necrosis factor receptor-associated factor 3 (TRAF3), an adaptor protein in tumor necrosis factor-related signaling cascades, as a key regulator of cardiac hypertrophy in response to pressure overload. TRAF3 expression was upregulated in hypertrophied mice hearts and failing human hearts. Four weeks after aortic banding, cardiac-specific conditional TRAF3-knockout mice exhibited significantly reduced cardiac hypertrophy, fibrosis, and dysfunction. Conversely, transgenic mice overexpressing TRAF3 in the heart developed exaggerated cardiac hypertrophy in response to pressure overload. TRAF3 also promoted an angiotensin II- or phenylephrine-induced hypertrophic response in isolated cardiomyocytes. Mechanistically, TRAF3 directly bound to TANK-binding kinase 1 (TBK1), causing increased TBK1 phosphorylation in response to hypertrophic stimuli. This interaction between TRAF3 and TBK1 further activated AKT signaling, which ultimately promoted the development of cardiac hypertrophy. Our findings not only reveal a key role of TRAF3 in regulating the hypertrophic response but also uncover TRAF3-TBK1-AKT as a novel signaling pathway in the development of cardiac hypertrophy and heart failure. This pathway may represent a potential therapeutic target for this pathological process.

  7. Role of Nodal-PITX2C signaling pathway in glucose-induced cardiomyocyte hypertrophy.

    PubMed

    Su, Dongmei; Jing, Sun; Guan, Lina; Li, Qian; Zhang, Huiling; Gao, Xiaobo; Ma, Xu

    2014-06-01

    Pathological cardiac hypertrophy is a major cause of morbidity and mortality in cardiovascular disease. Recent studies have shown that cardiomyocytes, in response to high glucose (HG) stimuli, undergo hypertrophic growth. While much work still needs to be done to elucidate this important mechanism of hypertrophy, previous works have showed that some pathways or genes play important roles in hypertrophy. In this study, we showed that sublethal concentrations of glucose (25 mmol/L) could induce cardiomyocyte hypertrophy with an increase in the cellular surface area and the upregulation of the atrial natriuretic peptide (ANP) gene, a hypertrophic marker. High glucose (HG) treatments resulted in the upregulation of the Nodal gene, which is under-expressed in cardiomyocytes. We also determined that the knockdown of the Nodal gene resisted HG-induced cardiomyocyte hypertrophy. The overexpression of Nodal was able to induce hypertrophy in cardiomyocytes, which was associated with the upregulation of the PITX2C gene. We also showed that increases in the PITX2C expression, in response to Nodal, were mediated by the Smad4 signaling pathway. This study is highly relevant to the understanding of the effects of the Nodal-PITX2C pathway on HG-induced cardiomyocyte hypertrophy, as well as the related molecular mechanisms.

  8. Cinaciguat prevents the development of pathologic hypertrophy in a rat model of left ventricular pressure overload

    PubMed Central

    Németh, Balázs Tamás; Mátyás, Csaba; Oláh, Attila; Lux, Árpád; Hidi, László; Ruppert, Mihály; Kellermayer, Dalma; Kökény, Gábor; Szabó, Gábor; Merkely, Béla; Radovits, Tamás

    2016-01-01

    Pathologic myocardial hypertrophy develops when the heart is chronically pressure-overloaded. Elevated intracellular cGMP-levels have been reported to prevent the development of pathologic myocardial hypertrophy, therefore we investigated the effects of chronic activation of the cGMP producing enzyme, soluble guanylate cyclase by Cinaciguat in a rat model of pressure overload-induced cardiac hypertrophy. Abdominal aortic banding (AAB) was used to evoke pressure overload-induced cardiac hypertrophy in male Wistar rats. Sham operated animals served as controls. Experimental and control groups were treated with 10 mg/kg/day Cinaciguat (Cin) or placebo (Co) p.o. for six weeks, respectively. Pathologic myocardial hypertrophy was present in the AABCo group following 6 weeks of pressure overload of the heart, evidenced by increased relative heart weight, average cardiomyocyte diameter, collagen content and apoptosis. Cinaciguat did not significantly alter blood pressure, but effectively attenuated all features of pathologic myocardial hypertrophy, and normalized functional changes, such as the increase in contractility following AAB. Our results demonstrate that chronic enhancement of cGMP signalling by pharmacological activation of sGC might be a novel therapeutic approach in the prevention of pathologic myocardial hypertrophy. PMID:27853261

  9. Cinaciguat prevents the development of pathologic hypertrophy in a rat model of left ventricular pressure overload.

    PubMed

    Németh, Balázs Tamás; Mátyás, Csaba; Oláh, Attila; Lux, Árpád; Hidi, László; Ruppert, Mihály; Kellermayer, Dalma; Kökény, Gábor; Szabó, Gábor; Merkely, Béla; Radovits, Tamás

    2016-11-17

    Pathologic myocardial hypertrophy develops when the heart is chronically pressure-overloaded. Elevated intracellular cGMP-levels have been reported to prevent the development of pathologic myocardial hypertrophy, therefore we investigated the effects of chronic activation of the cGMP producing enzyme, soluble guanylate cyclase by Cinaciguat in a rat model of pressure overload-induced cardiac hypertrophy. Abdominal aortic banding (AAB) was used to evoke pressure overload-induced cardiac hypertrophy in male Wistar rats. Sham operated animals served as controls. Experimental and control groups were treated with 10 mg/kg/day Cinaciguat (Cin) or placebo (Co) p.o. for six weeks, respectively. Pathologic myocardial hypertrophy was present in the AABCo group following 6 weeks of pressure overload of the heart, evidenced by increased relative heart weight, average cardiomyocyte diameter, collagen content and apoptosis. Cinaciguat did not significantly alter blood pressure, but effectively attenuated all features of pathologic myocardial hypertrophy, and normalized functional changes, such as the increase in contractility following AAB. Our results demonstrate that chronic enhancement of cGMP signalling by pharmacological activation of sGC might be a novel therapeutic approach in the prevention of pathologic myocardial hypertrophy.

  10. Phenylephrine-induced cardiac hypertrophy is attenuated by a histone acetylase inhibitor anacardic acid in mice.

    PubMed

    Peng, Chang; Luo, Xiaomei; Li, Shuo; Sun, Huichao

    2017-03-28

    Cardiac hypertrophy is a complex process involving highly coordinated but tight regulation of multiple elements, such as in epigenetics, which make an important contribution to myocardium remodeling and cardiac hypertrophy. Epigenetic regulations, particularly histone acetylation, have been implicated in cardiac hypertrophy, however, the exact mechanism is still largely unknown. In the present study, we explored the potential attenuating effects of Chinese herbal extract anacardic acid on phenylephrine-induced cardiac hypertrophy and the underlying mechanism. The mouse cardiac hypertrophy model was established and the hearts were collected from C57BL/6 mice for further analyses. The data showed that anacardic acid modulated the cardiac genes expression and attenuated the phenylephrine-induced cardiac hypertrophy via the suppression of histone acetylases activity and downstream cardiac genes. In addition, anacardic acid abrogated histone and MEF2A acetylation and DNA-binding activity by blocking p300-HAT and PCAF-HAT activities. In addition, anacardic acid normalized the cardiac hypertrophy-related genes expressions (ANP, BNP, cTnT, cTnI, β-MHC, and Cx43) induced by phenylephrine at the level of transcription and translation. In addition, anacardic acid did not affect the blood routine index, hepatic function, renal function, and myocardial enzymes. Therefore, anacardic acid may prove to be a candidate drug to cure hypertrophic cardiomyopathy.

  11. Myocyte cellular hypertrophy and hyperplasia contribute to ventricular wall remodeling in anemia-induced cardiac hypertrophy in rats.

    PubMed Central

    Olivetti, G.; Quaini, F.; Lagrasta, C.; Ricci, R.; Tiberti, G.; Capasso, J. M.; Anversa, P.

    1992-01-01

    To determine the effects of chronic anemia on the functional and structural characteristics of the heart, 1-month-old male rats were fed a diet deficient in iron and copper, which led to a hemoglobin concentration of 4.63 g/dl, for 8 weeks. At sacrifice, under fentanyl citrate and droperidol anesthesia, systolic, diastolic, and mean arterial blood pressures were decreased, whereas differential pressure was increased. Left ventricular systolic pressure and the ventricular rate of pressure rise (mmHg/s) were reduced by 9% and 14%, respectively. Moreover, developed peak systolic ventricular pressure and maximal dP/dt diminished 14% and 12%. After perfusion fixation of the coronary vasculature and the myocardium, at a left ventricular intracavitary pressure equal to the in vivo measured end diastolic pressure, a 10% thickening of the left ventricular wall was measured in association with a 13% increase in the equatorial cavitary diameter and a 44% augmentation in ventricular mass. The 52% hypertrophy of the right ventricle was characterized by an 11% thicker wall and a 37% larger ventricular area. The 33% expansion in the aggregate myocyte volume of the left ventricle was found to be due to a 14% myocyte cellular hypertrophy and a 17% myocyte cellular hyperplasia. These cellular parameters were calculated from the estimation of the number of myocyte nuclei per unit volume of myocardium in situ and the evaluation of the distribution of nuclei per cell in enzymatically dissociated myocytes. Myocyte cellular hyperplasia provoked a 9% increase in the absolute number of cells across the left ventricular wall. In contrast, myocyte cellular hypertrophy (42%) was responsible for the increase in myocyte volume of the right ventricle. The proliferative response of left ventricular myocytes was not capable of restoring diastolic cell stress, which was enhanced by the changes in ventricular anatomy with anemia. In conclusion, chronic anemia induced an unbalanced load on the left

  12. Abnormal Mechanical Loading Induces Cartilage Degeneration by Accelerating Meniscus Hypertrophy and Mineralization After ACL Injuries In Vivo

    PubMed Central

    Du, Guoqing; Zhan, Hongsheng; Ding, Daofang; Wang, Shaowei; Wei, Xiaochun; Wei, Fangyuan; Zhang, Jianzhong; Bilgen, Bahar; Reginato, Anthony M.; Fleming, Braden C.; Deng, Jin; Wei, Lei

    2016-01-01

    Background Although patients with an anterior cruciate ligament (ACL) injury have a high risk of developing posttraumatic osteoarthritis (PTOA), the role of meniscus hypertrophy and mineralization in PTOA after an ACL injury remains unknown. Purpose/Hypothesis The purpose of this study was to determine if menisci respond to abnormal loading and if an ACL injury results in meniscus hypertrophy and calcification. The hypotheses were that (1) abnormal mechanical loading after an ACL injury induces meniscus hypertrophy and mineralization, which correlates to articular cartilage damage in vivo, and (2) abnormal mechanical loading on bovine meniscus explants induces the overexpression of hypertrophic and mineralization markers in vitro. Study Design Controlled laboratory study. Methods In vivo guinea pig study (hypothesis 1): Three-month-old male Hartley guinea pigs (n = 9) underwent ACL transection (ACLT) on the right knee; the left knee served as the control. Calcification in the menisci was evaluated by calcein labeling 1 and 5 days before knee harvesting at 5.5 months. Cartilage and meniscus damage and mineralization were quantified by the Osteoarthritis Research Society International score and meniscus grade, respectively. Indian hedgehog (Ihh), matrix metalloproteinase–13 (MMP-13), collagen type X (Col X), progressive ankylosis homolog (ANKH), ectonucleotide pyrophosphatase/phosphodiesterase–1 (ENPP1), alkaline phosphatase (ALP), inorganic pyrophosphate (PPi), and inorganic phosphate (Pi) concentrations were evaluated by immunohistochemistry and enzyme-linked immunosorbent assay. In vitro bovine meniscus explant study (hypothesis 2): Bovine meniscus explants were subjected to 25% strain at 0.3 Hz for 1, 2, and 3 hours. Cell viability was determined using live/dead staining. The levels of mRNA expression and protein levels were measured using real-time quantitative reverse transcription polymerase chain reaction and Western blot after 24, 48, and 72 hours in

  13. Hepatocyte and Sertoli Cell Aquaporins, Recent Advances and Research Trends

    PubMed Central

    Bernardino, Raquel L.; Marinelli, Raul A.; Maggio, Anna; Gena, Patrizia; Cataldo, Ilaria; Alves, Marco G.; Svelto, Maria; Oliveira, Pedro F.; Calamita, Giuseppe

    2016-01-01

    Aquaporins (AQPs) are proteinaceous channels widespread in nature where they allow facilitated permeation of water and uncharged through cellular membranes. AQPs play a number of important roles in both health and disease. This review focuses on the most recent advances and research trends regarding the expression and modulation, as well as physiological and pathophysiological functions of AQPs in hepatocytes and Sertoli cells (SCs). Besides their involvement in bile formation, hepatocyte AQPs are involved in maintaining energy balance acting in hepatic gluconeogenesis and lipid metabolism, and in critical processes such as ammonia detoxification and mitochondrial output of hydrogen peroxide. Roles are played in clinical disorders including fatty liver disease, diabetes, obesity, cholestasis, hepatic cirrhosis and hepatocarcinoma. In the seminiferous tubules, particularly in SCs, AQPs are also widely expressed and seem to be implicated in the various stages of spermatogenesis. Like in hepatocytes, AQPs may be involved in maintaining energy homeostasis in these cells and have a major role in the metabolic cooperation established in the testicular tissue. Altogether, this information represents the mainstay of current and future investigation in an expanding field. PMID:27409609

  14. Hepatitis C Virus Infects Rhesus Macaque Hepatocytes and Simianized Mice

    PubMed Central

    Scull, Margaret A.; Shi, Chao; de Jong, Ype P.; Gerold, Gisa; Ries, Moritz; von Schaewen, Markus; Donovan, Bridget M.; Labitt, Rachael N.; Horwitz, Joshua A.; Gaska, Jenna M.; Hrebikova, Gabriela; Xiao, Jing W.; Flatley, Brenna; Fung, Canny; Chiriboga, Luis; Walker, Christopher M.; Evans, David T.; Rice, Charles M.; Ploss, Alexander

    2015-01-01

    At least 170 million people are chronically infected with hepatitis C virus (HCV). Due to the narrow host range of HCV and restricted use of chimpanzees, there is currently no suitable animal model for HCV pathogenesis studies or the development of a HCV vaccine. To identify cellular determinants of interspecies transmission and establish a novel immunocompetent model system, we examined the ability of HCV to infect hepatocytes from a small non-human primate, the rhesus macaque (Macaca mulatta). We show that the rhesus orthologs of critical HCV entry factors support viral glycoprotein-dependent virion uptake. Primary hepatocytes from rhesus macaques are also permissive for HCV RNA replication and particle production, which is enhanced when antiviral signaling is suppressed. We demonstrate that this may be due to the diminished capacity of HCV to antagonize MAVS-dependent innate cellular defenses. To test the ability of HCV to establish persistent replication in vivo, we engrafted primary rhesus macaque hepatocytes into immunocompromised xenorecipients. Inoculation of resulting simian liver chimeric mice with either HCV genotype 1a or 2a resulted in HCV serum viremia for up to 10 weeks. Conclusion: Together, these data indicate that rhesus macaques may be a viable model for HCV and implicate host immunity as a potential species-specific barrier to HCV infection. We conclude that suppression of host immunity or further viral adaptation may allow robust HCV infection in rhesus macaques and creation of a new animal model for studies of HCV pathogenesis, lentivirus coinfection and vaccine development. PMID:25820364

  15. Polyethylene glycol protects primary hepatocytes during supercooling preservation.

    PubMed

    Puts, C F; Berendsen, T A; Bruinsma, B G; Ozer, Sinan; Luitje, Martha; Usta, O Berk; Yarmush, M L; Uygun, K

    2015-08-01

    Cold storage (at 4°C) offers a compromise between the benefits and disadvantages of cooling. It allows storage of organs or cells for later use that would otherwise quickly succumb to warm ischemia, but comprises cold ischemia that, when not controlled properly, can result in severe damage as well by both similar and unique mechanisms. We hypothesized that polyethylene glycol (PEG) 35 kDa would ameliorate these injury pathways and improve cold primary hepatocyte preservation. We show that reduction of the storage temperature to below zero by means of supercooling, or subzero non-freezing, together with PEG supplementation increases the viable storage time of primary rat hepatocytes in University of Wisconsin (UW) solution from 1 day to 4 days. We find that the addition of 5% PEG 35 kDa to the storage medium prevents cold-induced lipid peroxidation and maintains hepatocyte viability and functionality during storage. These results suggest that PEG supplementation in combination with supercooling may enable a more optimized cell and organ preservation.

  16. Eccentric and concentric cardiac hypertrophy induced by exercise training: microRNAs and molecular determinants.

    PubMed

    Fernandes, T; Soci, U P R; Oliveira, E M

    2011-09-01

    Among the molecular, biochemical and cellular processes that orchestrate the development of the different phenotypes of cardiac hypertrophy in response to physiological stimuli or pathological insults, the specific contribution of exercise training has recently become appreciated. Physiological cardiac hypertrophy involves complex cardiac remodeling that occurs as an adaptive response to static or dynamic chronic exercise, but the stimuli and molecular mechanisms underlying transduction of the hemodynamic overload into myocardial growth are poorly understood. This review summarizes the physiological stimuli that induce concentric and eccentric physiological hypertrophy, and discusses the molecular mechanisms, sarcomeric organization, and signaling pathway involved, also showing that the cardiac markers of pathological hypertrophy (atrial natriuretic factor, β-myosin heavy chain and α-skeletal actin) are not increased. There is no fibrosis and no cardiac dysfunction in eccentric or concentric hypertrophy induced by exercise training. Therefore, the renin-angiotensin system has been implicated as one of the regulatory mechanisms for the control of cardiac function and structure. Here, we show that the angiotensin II type 1 (AT1) receptor is locally activated in pathological and physiological cardiac hypertrophy, although with exercise training it can be stimulated independently of the involvement of angiotensin II. Recently, microRNAs (miRs) have been investigated as a possible therapeutic approach since they regulate the translation of the target mRNAs involved in cardiac hypertrophy; however, miRs in relation to physiological hypertrophy have not been extensively investigated. We summarize here profiling studies that have examined miRs in pathological and physiological cardiac hypertrophy. An understanding of physiological cardiac remodeling may provide a strategy to improve ventricular function in cardiac dysfunction.

  17. MiR-30-regulated autophagy mediates angiotensin II-induced myocardial hypertrophy.

    PubMed

    Pan, Wei; Zhong, Yun; Cheng, Chuanfang; Liu, Benrong; Wang, Li; Li, Aiqun; Xiong, Longgen; Liu, Shiming

    2013-01-01

    Dysregulated autophagy may lead to the development of disease. Role of autophagy and the diagnostic potential of microRNAs that regulate the autophagy in cardiac hypertrophy have not been evaluated. A rat model of cardiac hypertrophy was established using transverse abdominal aortic constriction (operation group). Cardiomyocyte autophagy was enhanced in rats from the operation group, compared with those in the sham operation group. Moreover, the operation group showed up-regulation of beclin-1 (an autophagy-related gene), and down-regulation of miR-30 in cardiac tissue. The effects of inhibition and over-expression of the beclin-1 gene on the expression of hypertrophy-related genes and on autophagy were assessed. Angiotensin II-induced myocardial hypertrophy was found to be mediated by over-expression of the beclin-1 gene. A dual luciferase reporter assay confirmed that beclin-1 was a target gene of miR-30a. miR-30a induced alterations in beclin-1 gene expression and autophagy in cardiomyocytes. Treatment of cardiomyocytes with miR-30a mimic attenuated the Angiotensin II-induced up-regulation of hypertrophy-related genes and decreased in the cardiomyocyte surface area. Conversely, treatment with miR-30a inhibitor enhanced the up-regulation of hypertrophy-related genes and increased the surface area of cardiomyocytes induced by Angiotensin II. In addition, circulating miR-30 was elevated in patients with left ventricular hypertrophy, and circulating miR-30 was positively associated with left ventricular wall thickness. Collectively, these above-mentioned results suggest that Angiotensin II induces down-regulation of miR-30 in cardiomyocytes, which in turn promotes myocardial hypertrophy through excessive autophagy. Circulating miR-30 may be an important marker for the diagnosis of left ventricular hypertrophy.

  18. MiR-30-Regulated Autophagy Mediates Angiotensin II-Induced Myocardial Hypertrophy

    PubMed Central

    Pan, Wei; Zhong, Yun; Cheng, Chuanfang; Liu, Benrong; Wang, Li; Li, Aiqun; Xiong, Longgen; Liu, Shiming

    2013-01-01

    Dysregulated autophagy may lead to the development of disease. Role of autophagy and the diagnostic potential of microRNAs that regulate the autophagy in cardiac hypertrophy have not been evaluated. A rat model of cardiac hypertrophy was established using transverse abdominal aortic constriction (operation group). Cardiomyocyte autophagy was enhanced in rats from the operation group, compared with those in the sham operation group. Moreover, the operation group showed up-regulation of beclin-1 (an autophagy-related gene), and down-regulation of miR-30 in cardiac tissue. The effects of inhibition and over-expression of the beclin-1 gene on the expression of hypertrophy-related genes and on autophagy were assessed. Angiotensin II-induced myocardial hypertrophy was found to be mediated by over-expression of the beclin-1 gene. A dual luciferase reporter assay confirmed that beclin-1 was a target gene of miR-30a. miR-30a induced alterations in beclin-1 gene expression and autophagy in cardiomyocytes. Treatment of cardiomyocytes with miR-30a mimic attenuated the Angiotensin II-induced up-regulation of hypertrophy-related genes and decreased in the cardiomyocyte surface area. Conversely, treatment with miR-30a inhibitor enhanced the up-regulation of hypertrophy-related genes and increased the surface area of cardiomyocytes induced by Angiotensin II. In addition, circulating miR-30 was elevated in patients with left ventricular hypertrophy, and circulating miR-30 was positively associated with left ventricular wall thickness. Collectively, these above-mentioned results suggest that Angiotensin II induces down-regulation of miR-30 in cardiomyocytes, which in turn promotes myocardial hypertrophy through excessive autophagy. Circulating miR-30 may be an important marker for the diagnosis of left ventricular hypertrophy. PMID:23326547

  19. Becker muscular dystrophy with widespread muscle hypertrophy and a non-sense mutation of exon 2.

    PubMed

    Witting, N; Duno, M; Vissing, J

    2013-01-01

    Becker muscular dystrophy features progressive proximal weakness, wasting and often focal hypertrophy. We present a patient with pain and cramps from adolescence. Widespread muscle hypertrophy, preserved muscle strength and a 10-20-fold raised CPK were noted. Muscle biopsy was dystrophic, and Western blot showed a 95% reduction of dystrophin levels. Genetic analyses revealed a non-sense mutation in exon 2 of the dystrophin gene. This mutation is predicted to result in a Duchenne phenotype, but resulted in a mild Becker muscular dystrophy with widespread muscle hypertrophy. We suggest that this unusual phenotype is caused by translation re-initiation downstream from the mutation site.

  20. Inhibition of platelet-derived growth factor signaling prevents muscle fiber growth during skeletal muscle hypertrophy.

    PubMed

    Sugg, Kristoffer B; Korn, Michael A; Sarver, Dylan C; Markworth, James F; Mendias, Christopher L

    2017-03-01

    The platelet-derived growth factor receptors alpha and beta (PDGFRα and PDGFRβ) mark fibroadipogenic progenitor cells/fibroblasts and pericytes in skeletal muscle, respectively. While the role that these cells play in muscle growth and development has been evaluated, it was not known whether the PDGF receptors activate signaling pathways that control transcriptional and functional changes during skeletal muscle hypertrophy. To evaluate this, we inhibited PDGFR signaling in mice subjected to a synergist ablation muscle growth procedure, and performed analyses 3 and 10 days after induction of hypertrophy. The results from this study indicate that PDGF signaling is required for fiber hypertrophy, extracellular matrix production, and angiogenesis that occur during muscle growth.

  1. Vasectomy and its reversal.

    PubMed

    Belker, A M

    1985-12-01

    Techniques, results, complications, and medicolegal aspects of vasectomy are discussed in this article. Emphasis is placed on techniques that prevent spontaneous recanalization of the ends of the vas deferens after vasectomy. Factors that affect the reversibility of vasectomy are discussed. New microsurgical techniques of vasectomy reversal are described, and results of these new techniques are compared with results of nonmicrosurgical techniques of vasectomy reversal. Indications for bypass vasoepididymostomy during vasectomy reversal procedures, as well as techniques for performing vasoepididymostomy, are discussed.

  2. Stimulation of fatty acid oxidation by a 3-thia fatty acid reduces triacylglycerol secretion in cultured rat hepatocytes.

    PubMed

    Skrede, S; Bremer, J; Berge, R K; Rustan, A C

    1994-08-01

    The present work shows that when mitochondrial beta-oxidation is stimulated by the hypolipemic, non-beta-oxidizable fatty acid analogue tetradecylthioacetic acid, there is a decrease in the secretion of triacylglycerol in cultured rat hepatocytes. In order to study the effects of tetradecylthioacetic acid in cells with different fatty acid oxidation rates, cells were grown without or with L-carnitine supplement or with addition of the beta-oxidation inhibitor L-aminocarnitine. In cells grown without and with L-carnitine in the medium, the oxidation of [1-14C]oleic acid was stimulated by tetradecylthioacetic acid, whereas it was not significantly changed by palmitic acid. In cells grown with L-aminocarnitine, oxidation of [1-14C]oleic acid was almost abolished both in the absence and in presence of tetradecylthioacetic acid. The effect of tetradecylthioacetic acid and palmitic acid on incorporation of [1-14C]oleic acid into triacylglycerol was similar under all conditions. In the presence of L-carnitine, secretion of oleic acid-labeled triacylglycerol was reduced significantly more by tetradecylthioacetic acid than by palmitic acid. The effects of tetradecylthioacetic acid and palmitic acid on secretion of oleic acid-labeled triacylglycerol were reversed in cells grown with L-aminocarnitine, where palmitic acid was the stronger inhibitor. These results were substantiated by determination of mass of triacylglycerol secreted. It is concluded that tetradecylthioacetic acid reduces secretion of triacylglycerol from rat hepatocytes mainly by acutely stimulating fatty acid oxidation.

  3. Reverse Correlation in Neurophysiology

    ERIC Educational Resources Information Center

    Ringach, Dario; Shapley, Robert

    2004-01-01

    This article presents a review of reverse correlation in neurophysiology. We discuss the basis of reverse correlation in linear transducers and in spiking neurons. The application of reverse correlation to measure the receptive fields of visual neurons using white noise and m-sequences, and classical findings about spatial and color processing in…

  4. Species-specific toxicity of troglitazone on rats and human by gel entrapped hepatocytes

    SciTech Connect

    Shen, Chong; Meng, Qin; Zhang, Guoliang

    2012-01-01

    Troglitazone, despite passing preclinical trials on animals, was shortly withdrawn from market due to its severe hepatotoxicity in clinic. As rat hepatocyte monolayer consistently showed sensitive troglitazone toxicity as human hepatocyte monolayer in contrast to the species-specific toxicity in vivo, this paper utilized both hepatocytes in three-dimensional culture of gel entrapment to reflect the species difference on hepatotoxicity. Rat hepatocytes in gel entrapment did not show obvious cellular damage even under a long-term exposure for 21 days while gel entrapped human hepatocytes significantly displayed oxidative stress, steatosis, mitochondrial damage and cell death at a short exposure for 4 days. As a result, the detected species-specific toxicity of troglitazone between gel entrapped rat and human hepatocytes consisted well with the situation in vivo but was in a sharp contrast to the performance of two hepatocytes by monolayer culture. Such contradictory toxicity of rat hepatocytes between monolayer and gel entrapment culture could be explained by the fact that troglitazone was cleared more rapidly in gel entrapment than in monolayer culture. Similarly, the differential clearance of troglitazone in rat and human might also explain its species-specific toxicity. Therefore, gel entrapment of hepatocytes might serve as a platform for evaluation of drug toxicity at early stage of drug development by reducing costs, increasing the likelihood of clinical success and limiting human exposure to unsafe drugs. -- Highlights: ► Species-specific toxicity of troglitazone reflected by rat/human hepatocytes ► 3D hepatocytes in 21 days’ long-term culture used for drug hepatotoxicity ► Oversensitive toxicity in hepatocyte monolayer by slow troglitazone clearance.

  5. DNA synthesis in periportal and perivenous hepatocytes of intact and hepatectomized young mice.

    PubMed

    Fernández-Blanco, A; Inda, A M; Errecalde, A L

    2015-01-01

    DNA synthesis of hepatocytes in two areas of Intact and Hepatectomized young mice liver along a circadian period was studied. DNA synthesis was significantly different at all analyzed time points in Intact and Hepatectomized animals. Differences between periportal and perivenous hepatocytes were found in hepatectomized animals at 04/42 and 08/46 hr of day/hour post-hepatectomy. DNAs peak in periportal hepatocytes regenerating liver occurs 4 hr earlier than in perivenous hepatocytes, probably reflecting their shorter G1 phase. Besides, daily mean values of regenerating livers were higher than those observed in Intact animals, as a consequence of surgical removal.

  6. Gel entrapment culture of rat hepatocytes for investigation of tetracycline-induced toxicity

    SciTech Connect

    Shen Chong; Meng Qin Schmelzer, Eva; Bader, Augustinus

    2009-07-15

    This paper aimed to explore three-dimensionally cultured hepatocytes for testing drug-induced nonalcoholic steatohepatitis. Gel entrapped rat hepatocytes were applied for investigation of the tetracycline-induced steatohepatitis, while hepatocyte monolayer was set as a control. The toxic responses of hepatocytes were systematically evaluated by measuring cell viability, liver-specific function, lipid accumulation, oxidative stress, adenosine triphosphate content and mitochondrial membrane potential. The results suggested that gel entrapped hepatocytes showed cell death after 96 h of tetracycline treatment at 25 {mu}M which is equivalent to toxic serum concentration in rats, while hepatocyte monolayer showed cell death at a high dose of 200 {mu}M. The concentration-dependent accumulation of lipid as well as mitochondrial damage were regarded as two early events for tetracycline hepatotoxicity in gel entrapment culture due to their detectability ahead of subsequent increase of oxidative stress and a final cell death. Furthermore, the potent protection of fenofibrate and fructose-1,6-diphosphate were evidenced in only gel entrapment culture with higher expressions on the genes related to {beta}-oxidation than hepatocyte monolayer, suggesting the mediation of lipid metabolism and mitochondrial damage in tetracycline toxicity. Overall, gel entrapped hepatocytes in three-dimension reflected more of the tetracycline toxicity in vivo than hepatocyte monolayer and thus was suggested as a more relevant system for evaluating steatogenic drugs.

  7. Three-dimensional (3D) printing of mouse primary hepatocytes to generate 3D hepatic structure

    PubMed Central

    Kim, Yohan; Kang, Kyojin; Jeong, Jaemin; Paik, Seung Sam; Kim, Ji Sook; Park, Su A; Kim, Wan Doo; Park, Jisun

    2017-01-01

    Purpose The major problem in producing artificial livers is that primary hepatocytes cannot be cultured for many days. Recently, 3-dimensional (3D) printing technology draws attention and this technology regarded as a useful tool for current cell biology. By using the 3D bio-printing, these problems can be resolved. Methods To generate 3D bio-printed structures (25 mm × 25 mm), cells-alginate constructs were fabricated by 3D bio-printing system. Mouse primary hepatocytes were isolated from the livers of 6–8 weeks old mice by a 2-step collagenase method. Samples of 4 × 107 hepatocytes with 80%–90% viability were printed with 3% alginate solution, and cultured with well-defined culture medium for primary hepatocytes. To confirm functional ability of hepatocytes cultured on 3D alginate scaffold, we conducted quantitative real-time polymerase chain reaction and immunofluorescence with hepatic marker genes. Results Isolated primary hepatocytes were printed with alginate. The 3D printed hepatocytes remained alive for 14 days. Gene expression levels of Albumin, HNF-4α and Foxa3 were gradually increased in the 3D structures. Immunofluorescence analysis showed that the primary hepatocytes produced hepatic-specific proteins over the same period of time. Conclusion Our research indicates that 3D bio-printing technique can be used for long-term culture of primary hepatocytes. It can therefore be used for drug screening and as a potential method of producing artificial livers. PMID:28203553

  8. HGF Secreted by Activated Kupffer Cells Induces Apoptosis of Plasmodium-Infected Hepatocytes

    PubMed Central

    Gonçalves, Lígia Antunes; Rodo, Joana; Rodrigues-Duarte, Lurdes; de Moraes, Luciana Vieira; Penha-Gonçalves, Carlos

    2017-01-01

    Malaria liver stage infection is an obligatory parasite development step and represents a population bottleneck in Plasmodium infections, providing an advantageous target for blocking parasite cycle progression. Parasite development inside hepatocytes implies a gross cellular insult evoking innate host responses to counteract intra-hepatocytic infection. Using primary hepatocyte cultures, we investigated the role of Kupffer cell-derived hepatocyte growth factor (HGF) in malaria liver stage infection. We found that Kupffer cells from Plasmodium-infected livers produced high levels of HGF, which trigger apoptosis of infected hepatocytes through a mitochondrial-independent apoptosis pathway. HGF action in infected hepatocyte primary cultures results in a potent reduction of parasite yield by specifically sensitizing hepatocytes carrying established parasite exo-erythrocytic forms to undergo apoptosis. This apoptosis mechanism is distinct from cell death that is spontaneously induced in infected cultures and is governed by Fas signaling modulation through a mitochondrial-dependent apoptosis pathway. This work indicates that HGF and Fas signaling pathways are part of an orchestrated host apoptosis response that occurs during malaria liver stage infection, decreasing the success of infection of individual hepatocytes. Our results raise the hypothesis that paracrine signals derived from Kupffer cell activation are implicated in directing death of hepatocytes infected with the malaria parasite. PMID:28220125

  9. Cholesterol Enhances the Toxic Effect of Ethanol and Acetaldehyde in Primary Mouse Hepatocytes

    PubMed Central

    López-Islas, Anayelly; Chagoya-Hazas, Victoria; Pérez-Aguilar, Benjamin; Palestino-Domínguez, Mayrel; Souza, Verónica; Miranda, Roxana U.; Bucio, Leticia; Gómez-Quiroz, Luis Enrique; Gutiérrez-Ruiz, María-Concepción

    2016-01-01

    Obesity and alcohol consumption are risk factors for hepatic steatosis, and both commonly coexist. Our objective was to evaluate the effect of ethanol and acetaldehyde on primary hepatocytes obtained from mice fed for two days with a high cholesterol (HC) diet. HC hepatocytes increased lipid and cholesterol content. HC diet sensitized hepatocytes to the toxic effect of ethanol and acetaldehyde. Cyp2E1 content increased with HC diet, as well as in those treated with ethanol or acetaldehyde, while the activity of this enzyme determined in microsomes increased in the HC and in all ethanol treated hepatocytes, HC and CW. Oxidized proteins were increased in the HC cultures treated or not with the toxins. Transmission electron microscopy showed endoplasmic reticulum (ER) stress and megamitochondria in hepatocytes treated with ethanol as in HC and the ethanol HC treated hepatocytes. ER stress determined by PERK content was increased in ethanol treated hepatocytes from HC mice and CW. Nuclear translocation of ATF6 was observed in HC hepatocytes treated with ethanol, results that indicate that lipids overload and ethanol treatment favor ER stress. Oxidative stress, ER stress, and mitochondrial damage underlie potential mechanisms for increased damage in steatotic hepatocyte treated with ethanol. PMID:26788255

  10. Cholesterol Enhances the Toxic Effect of Ethanol and Acetaldehyde in Primary Mouse Hepatocytes.

    PubMed

    López-Islas, Anayelly; Chagoya-Hazas, Victoria; Pérez-Aguilar, Benjamin; Palestino-Domínguez, Mayrel; Souza, Verónica; Miranda, Roxana U; Bucio, Leticia; Gómez-Quiroz, Luis Enrique; Gutiérrez-Ruiz, María-Concepción

    2016-01-01

    Obesity and alcohol consumption are risk factors for hepatic steatosis, and both commonly coexist. Our objective was to evaluate the effect of ethanol and acetaldehyde on primary hepatocytes obtained from mice fed for two days with a high cholesterol (HC) diet. HC hepatocytes increased lipid and cholesterol content. HC diet sensitized hepatocytes to the toxic effect of ethanol and acetaldehyde. Cyp2E1 content increased with HC diet, as well as in those treated with ethanol or acetaldehyde, while the activity of this enzyme determined in microsomes increased in the HC and in all ethanol treated hepatocytes, HC and CW. Oxidized proteins were increased in the HC cultures treated or not with the toxins. Transmission electron microscopy showed endoplasmic reticulum (ER) stress and megamitochondria in hepatocytes treated with ethanol as in HC and the ethanol HC treated hepatocytes. ER stress determined by PERK content was increased in ethanol treated hepatocytes from HC mice and CW. Nuclear translocation of ATF6 was observed in HC hepatocytes treated with ethanol, results that indicate that lipids overload and ethanol treatment favor ER stress. Oxidative stress, ER stress, and mitochondrial damage underlie potential mechanisms for increased damage in steatotic hepatocyte treated with ethanol.

  11. Toxicity of microcystins in the isolated hepatocytes of common carp (Cyprinus carpio L.).

    PubMed

    Li, Xiao-Yu; Wang, Jie; Liang, Jun-Bo; Liu, Yong-Ding

    2007-07-01

    The toxicity of hepatotoxic microcystins produced mainly by Microcystis aeruginosa in mammals and fishes was well studied in recent years. However, there were scarcely reports in toxic effects of microcystins on isolated hepatocytes of fishes, especially investigation of microcystin-induced apoptosis and/or necrosis in carp hepatocytes. In the present study, the isolated hepatocytes of common carp were exposed to various concentrations of microcystins (0.01, 0.1, 1, 10, 100, 1000 microg L(-1)) for 2, 4, 8, 16 and 24h, respectively, and cytotoxicity of microcystins in the toxin-treated cells was determined. Results of this study showed that cytotoxicity of microcystins on carp hepatocytes was time and dose-dependent, and the approximate LC(50) of microcystins in carp hepatocytes was 169.2 microg L(-1). The morphological changes typical of apoptosis, such as blebbing of cell membrane, condensation and fragmentation of cell nucleus were observed in the hepatocytes exposed to microcystins (1, 10 and 100 microg L(-1)) using fluorescence and differential interference contrast microscopy. Agarose gel electrophoresis of DNA demonstrated a typical apoptotic "ladder pattern" in microcystin-treated hepatocytes after 16 h of exposure. Results of the present study indicated that the form of cell death in microcystin-treated hepatocytes depend on the exposure dose of toxin. When lower concentration of microcystins (10 and 100 microg L(-1)) was used for exposure, carp hepatocytes died in apoptosis while, when higher one used (1000 microg L(-1)), they died in the form of necrosis.

  12. A Xanthine-Derivative K+-Channel Opener Protects against Serotonin-Induced Cardiomyocyte Hypertrophy via the Modulation of Protein Kinases

    PubMed Central

    Kuo, Hsuan-Fu; Lai, Yan-Jie; Wu, Jung-Chou; Lee, Kun-Tai; Chu, Chih-Sheng; Chen, Ing-Jun; Wu, Jiunn-Ren; Wu, Bin-Nan

    2014-01-01

    This study investigated whether KMUP-1, a xanthine-derivative K+ channel opener, could prevent serotonin-induced hypertrophy in H9c2 cardiomyocytes via L-type Ca2+ channels (LTCCs). Rat heart-derived H9c2 cells were incubated with serotonin (10 μM) for 4 days. The cell size increased by 155.5%, and this was reversed by KMUP-1 (≥1 μM), and attenuated by the LTCC blocker verapamil (1 μM) and the 5-HT2A antagonist ketanserin (0.1 μM), but unaffected by the 5-HT2B antagonist SB206553. A perforated whole-cell patch-clamp technique was used to investigate Ca2+ currents through LTCCs in serotonin-induced H9c2 hypertrophy, in which cell capacitance and current density were increased. The LTCC current (ICa,L) increased ~2.9-fold in serotonin-elicited H9c2 hypertrophy, which was attenuated by verapamil and ketanserin, but not affected by SB206553 (0.1 μM). Serotonin-increased ICa,L was reduced by KMUP-1, PKA and PKC inhibitors (H-89, 1 μM and chelerythrine, 1 μM) while the current was enhanced by the PKC activator PMA, (1 μM) but not the PKA activator 8-Br-cAMP (100 μM), and was abolished by KMUP-1. In contrast, serotonin-increased ICa,L was blunted by the PKG activator 8-Br-cGMP (100 μM), but unaffected by the PKG inhibitor KT5823 (1 μM). Notably, KMUP-1 blocked serotonin-increased ICa,L but this was partially reversed by KT5823. In conclusion, serotonin-increased ICa,L could be due to activated 5-HT2A receptor-mediated PKA and PKC cascades, and/or indirect interaction with PKG. KMUP-1 prevents serotonin-induced H9c2 cardiomyocyte hypertrophy, which can be attributed to its PKA and PKC inhibition, and/or PKG stimulation. PMID:24391452

  13. Quantum Operation Time Reversal

    SciTech Connect

    Crooks, Gavin E.

    2008-03-25

    The dynamics of an open quantum system can be described by a quantum operation: A linear, complete positive map of operators. Here, I exhibit a compact expression for the time reversal of a quantum operation, which is closely analogous to the time reversal of a classical Markov transition matrix. Since open quantum dynamics are stochastic, and not, in general, deterministic, the time reversal is not, in general, an inversion of the dynamics. Rather, the system relaxes toward equilibrium in both the forward and reverse time directions. The probability of a quantum trajectory and the conjugate, time reversed trajectory are related by the heat exchanged with the environment.

  14. Magnetic Cell Labeling of Primary and Stem Cell-Derived Pig Hepatocytes for MRI-Based Cell Tracking of Hepatocyte Transplantation

    PubMed Central

    Roach, Dwayne R.; Garrett, Wesley M.; Welch, Glenn; Caperna, Thomas J.; Talbot, Neil C.; Shapiro, Erik M.

    2015-01-01

    Pig hepatocytes are an important investigational tool for optimizing hepatocyte transplantation schemes in both allogeneic and xenogeneic transplant scenarios. MRI can be used to serially monitor the transplanted cells, but only if the hepatocytes can be labeled with a magnetic particle. In this work, we describe culture conditions for magnetic cell labeling of cells from two different pig hepatocyte cell sources; primary pig hepatocytes (ppHEP) and stem cell-derived hepatocytes (PICM-19FF). The magnetic particle is a micron-sized iron oxide particle (MPIO) that has been extensively studied for magnetic cell labeling for MRI-based cell tracking. ppHEP could endocytose MPIO with labeling percentages as high as 70%, achieving iron content as high as ~55 pg/cell, with >75% viability. PICM-19FF had labeling >97%, achieving iron content ~38 pg/cell, with viability >99%. Extensive morphological and functional assays indicated that magnetic cell labeling was benign to the cells. The results encourage the use of MRI-based cell tracking for the development and clinical use of hepatocyte transplantation methodologies. Further, these results generally highlight the importance of functional cell assays in the evaluation of contrast agent biocompatibility. PMID:25856627

  15. A missense mutant myostatin causes hyperplasia without hypertrophy in the mouse muscle.

    PubMed

    Nishi, Masumi; Yasue, Akihiro; Nishimatu, Shinichirou; Nohno, Tsutomu; Yamaoka, Takashi; Itakura, Mitsuo; Moriyama, Keiji; Ohuchi, Hideyo; Noji, Sumihare

    2002-04-26

    Myostatin, which is a member of the TGF-beta superfamily, is a negative regulator of skeletal muscle formation. Double-muscled Piedmontese cattle have a C313Y mutation in myostatin and show increased skeletal muscle mass which resulted from an increase of myofiber number (hyperplasia) without that of myofiber size (hypertrophy). To examine whether this mutation in myostatin gene affects muscle development in a dominant negative manner, we generated transgenic mice overexpressing the mutated gene. The transgenic mice exhibited dramatic increases in the skeletal muscle mass resulting from hyperplasia without hypertrophy. In contrast, it has been reported that a myostatin mutated at its cleavage site produces hypertrophy without hyperplasia in the muscle. Thus, these results suggest that (1) the myostatin containing the missense mutation exhibits a dominant negative activity and that (2) there are two types in the dominant negative form of myostatin, causing either hypertrophy or hyperplasia.

  16. Solving the cardiac hypertrophy riddle: The angiotensin II-mechanical stress connection.

    PubMed

    Zablocki, Daniela; Sadoshima, Junichi

    2013-11-08

    A series of studies conducted 20 years ago, documenting the cardiac hypertrophy phenotype and its underlying signaling mechanism induced by angiotensin II (Ang II) and mechanical stress, showed a remarkable similarity between the effect of the Gαq agonist and that of mechanical forces on cardiac hypertrophy. Subsequent studies confirmed the involvement of autocrine/paracrine mechanisms, including stretch-induced release of Ang II in load-induced cardiac hypertrophy. Recent studies showed that the Ang II type 1 (AT1) receptor is also directly activated by mechanical forces, suggesting that AT1 receptors play an important role in mediating load-induced cardiac hypertrophy through both ligand- and mechanical stress-dependent mechanisms.

  17. Thymic involution in the suspended rat - Adrenal hypertrophy and glucocorticoid receptor content

    NASA Technical Reports Server (NTRS)

    Steffen, J. M.; Musacchia, X. J.

    1986-01-01

    The relationship between thymic involution and adrenal hypertrophy is studied. The thymus, adrenal glands, and tissue water content are evaluated in male Sprague rats suspended in antiorthostatic (AO) or orthostatic (O) positions. A 50 percent decrease in the wet weight of the thymus and hypertrophy of the adrenal glands are observed during the seven days of AO suspension. After seven days of recovery the thymus weight is increased to control level; however, the hypertrophy of the adrenal glands remains unchanged. Thymic and renal responses in O postioned rats are similar to AO reactions. Thymic glucocorticoid (GC) receptor concentrations in the rats are analyzed; a 20 percent decrease in GC receptor site concentration, which is related to thymic involution, is detected in both AO and O rats. It is concluded that there is a temporal correlation between thymic involution and adrenal hypertrophy, which is not affected by AO positioning, and thymic involution is not associated with an increased sensitivity to GC.

  18. [Obstructive sleep apnea-hypopnea syndrome in children: beyond adenotonsillar hypertrophy].

    PubMed

    Esteller, Eduard

    2015-01-01

    The prevalence of obstructive sleep apnea-hypopnea syndrome in the general childhood population is 1-2% and the most common cause is adenotonsillar hypertrophy. However, beyond adenotonsillar hypertrophy, there are other highly prevalent causes of this syndrome in children. The causes are often multifactorial and include muscular hypotonia, dentofacial abnormalities, soft tissue hypertrophy of the airway, and neurological disorders). Collaboration between different specialties involved in the care of these children is essential, given the wide variability of conditions and how frequently different factors are involved in their genesis, as well as the different treatments to be applied. We carried out a wide literature review of other causes of obstructive sleep apnea-hypopnea syndrome in children, beyond adenotonsillar hypertrophy. We organised the prevalence of this syndrome in each pathology and the reasons that cause it, as well as their interactions and management, in a consistent manner.

  19. Isolated papillary muscle hypertrophy: A gap in our knowledge of hypertrophic cardiomyopathy?

    PubMed

    Ferreira, Catarina; Delgado, Carlos; Vázquez, María; Trinidad, Carmen; Vilar, Manuel

    2014-06-01

    Increased thickness of left ventricular walls is the predominant characteristic and one of the diagnostic criteria of hypertrophic cardiomyopathy (HCM). This case illustrates an uncommon but important finding of isolated hypertrophy of the papillary muscles (PMs), observed in a young woman in whom an abnormal electrocardiogram was initially detected. During the investigation isolated PM hypertrophy was identified. The structural characteristics of the PMs have received scant attention in this setting and there is little information in the literature on this entity, whose real prevalence and clinical significance remain to be determined. The available information relates solitary PM hypertrophy with an early form or a different pattern of HCM. In this case PM hypertrophy was only detected due to the finding of an abnormal electrocardiogram, which prompted further diagnostic tests and a search for possible etiologies.

  20. Pathogenesis of cardiac hypertrophy in iron deficiency anaemia: the role of noradrenaline.

    PubMed Central

    Rossi, M. A.; Carillo, S. V.

    1982-01-01

    This study examined the effect of long-term administration of reserpine, an adrenergic blocking agent, on cardiac hypertrophy in animals with severe iron deficiency anaemia. This condition was induced by feeding rats on an iron-deficient diet for 30 days from the time of weaning. Anaemia was indicated by lowering of blood haemoglobin levels. Reserpine was administered i.p. (0.15 mg/kg body wt) every day during the experiment. Marked cardiac hypertrophy, as indicated by increase heart weight and increased size of cardiac muscle cells, was evidenced in iron-deficient rats, while the heart weights and myocardial cell size of drug-treated anaemic rats were in the normal range. The successful prevention of cardiac hypertrophy in anaemic iron-deficient rats by reserpine administration supports the hypothesis that noradrenaline plays a key role in the cardiac-hypertrophy process in iron deficiency anaemia. PMID:6212077

  1. Lipopolysaccharide and Tumor Necrosis Factor Alpha Inhibit Interferon Signaling in Hepatocytes by Increasing Ubiquitin-Like Protease 18 (USP18) Expression

    PubMed Central

    MacParland, Sonya A.; Ma, Xue-Zhong; Chen, Limin; Khattar, Ramzi; Cherepanov, Vera; Selzner, Markus; Feld, Jordan J.; Selzner, Nazia

    2016-01-01

    ABSTRACT Inflammation may be maladaptive to the control of viral infection when it impairs interferon (IFN) responses, enhancing viral replication and spread. Dysregulated immunity as a result of inappropriate innate inflammatory responses is a hallmark of chronic viral infections such as, hepatitis B virus and hepatitis C virus (HCV). Previous studies from our laboratory have shown that expression of an IFN-stimulated gene (ISG), ubiquitin-like protease (USP)18 is upregulated in chronic HCV infection, leading to impaired hepatocyte responses to IFN-α. We examined the ability of inflammatory stimuli, including tumor necrosis factor alpha (TNF-α), lipopolysaccharide (LPS), interleukin-6 (IL-6) and IL-10 to upregulate hepatocyte USP18 expression and blunt the IFN-α response. Human hepatoma cells and primary murine hepatocytes were treated with TNF-α/LPS/IL-6/IL-10 and USP18, phosphorylated (p)-STAT1 and myxovirus (influenza virus) resistance 1 (Mx1) expression was determined. Treatment of Huh7.5 cells and primary murine hepatocytes with LPS and TNF-α, but not IL-6 or IL-10, led to upregulated USP18 expression and induced an IFN-α refractory state, which was reversed by USP18 knockdown. Liver inflammation was induced in vivo using a murine model of hepatic ischemia/reperfusion injury. Hepatic ischemia/reperfusion injury led to an induction of USP18 expression in liver tissue and promotion of lymphocytic choriomeningitis replication. These data demonstrate that certain inflammatory stimuli (TNF-α and LPS) but not others (IL-6 and IL-10) target USP18 expression and thus inhibit IFN signaling. These findings represent a new paradigm for how inflammation alters hepatic innate immune responses, with USP18 representing a potential target for intervention in various inflammatory states. IMPORTANCE Inflammation may prevent the control of viral infection when it impairs the innate immune response, enhancing viral replication and spread. Blunted immunity as a result of

  2. Negative feedback regulation of Homer 1a on norepinephrine-dependent cardiac hypertrophy

    SciTech Connect

    Chiarello, Carmelina; Bortoloso, Elena; Carpi, Andrea; Furlan, Sandra; Volpe, Pompeo

    2013-07-15

    Homers are scaffolding proteins that modulate diverse cell functions being able to assemble signalling complexes. In this study, the presence, sub-cellular distribution and function of Homer 1 was investigated. Homer 1a and Homer 1b/c are constitutively expressed in cardiac muscle of both mouse and rat and in HL-1 cells, a cardiac cell line. As judged by confocal immunofluorescence microscopy, Homer 1a displays sarcomeric and peri-nuclear localization. In cardiomyocytes and cultured HL-1 cells, the hypertrophic agonist norepinephrine (NE) induces α{sub 1}-adrenergic specific Homer 1a over-expression, with a two-to-three-fold increase within 1 h, and no up-regulation of Homer 1b/c, as judged by Western blot and qPCR. In HL-1 cells, plasmid-driven over-expression of Homer 1a partially antagonizes activation of ERK phosphorylation and ANF up-regulation, two well-established, early markers of hypertrophy. At the morphometric level, NE-induced increase of cell size is likewise and partially counteracted by exogenous Homer 1a. Under the same experimental conditions, Homer 1b/c does not have any effect on ANF up-regulation nor on cell hypertrophy. Thus, Homer 1a up-regulation is associated to early stages of cardiac hypertrophy and appears to play a negative feedback regulation on molecular transducers of hypertrophy. -- Highlights: • Homer 1a is constitutively expressed in cardiac tissue. • In HL-1 cells, norepinephrine activates signaling pathways leading to hypertrophy. • Homer 1a up-regulation is an early event of norepinephrine-induced hypertrophy. • Homer 1a plays a negative feedback regulation modulating pathological hypertrophy. • Over-expression of Homer 1a per se does not induce hypertrophy.

  3. The metabolic and temporal basis of muscle hypertrophy in response to resistance exercise.

    PubMed

    Brook, Matthew S; Wilkinson, Daniel J; Smith, Kenneth; Atherton, Philip J

    2016-09-01

    Constituting ∼40% of body mass, skeletal muscle has essential locomotory and metabolic functions. As such, an insight into the control of muscle mass is of great importance for maintaining health and quality-of-life into older age, under conditions of cachectic disease and with rehabilitation. In healthy weight-bearing individuals, muscle mass is maintained by the equilibrium between muscle protein synthesis (MPS) and muscle protein breakdown; when this balance tips in favour of MPS hypertrophy occurs. Despite considerable research into pharmacological/nutraceutical interventions, resistance exercise training (RE-T) remains the most potent stimulator of MPS and hypertrophy (in the majority of individuals). However, the mechanism(s) and time course of hypertrophic responses to RE-T remain poorly understood. We would suggest that available data are very much in favour of the notion that the majority of hypertrophy occurs in the early phases of RE-T (though still controversial to some) and that, for the most part, continued gains are hard to come by. Whilst the mechanisms of muscle hypertrophy represent the culmination of mechanical, auto/paracrine and endocrine events, the measurement of MPS remains a cornerstone for understanding the control of hypertrophy - mainly because it is the underlying driving force behind skeletal muscle hypertrophy. Development of sophisticated isotopic techniques (i.e. deuterium oxide) that lend to longer term insight into the control of hypertrophy by sustained RE-T will be paramount in providing insights into the metabolic and temporal regulation of hypertrophy. Such technologies will have broad application in muscle mass intervention for both athletes and for mitigating disease/age-related cachexia and sarcopenia, alike.

  4. Cyclin-dependent kinase inhibitor, p21Waf1, regulates vascular smooth muscle cell hypertrophy.

    PubMed

    Okamoto, Kenichi; Kato, Seiya; Arima, Nobuyuki; Fujii, Teruhiko; Morimatsu, Minoru; Imaizumi, Tsutomu

    2004-04-01

    In the process of vascular diseases, smooth muscle cells (SMC) undergo not only hyperplasia but also hypertrophy, resulting in vascular remodeling. A cyclin-dependent kinase inhibitor (CDKI), p21Waf1, has been shown to play an important role in SMC hyperplasia. Here we investigated a potential role of p21Waf1 in SMC hypertrophy. An exposure of cultured rat SMC to serum drove the cell cycle progression with up-regulation of various cell cycle markers and increased activities of cyclin-dependent kinases, but did not cause SMC hypertrophy. In contrast, incubation of SMC for 48 h with angiotensin II (AII, 100 nmol/l) resulted in a significant increase in the cell size measured by flowcytometric forward-angle light scatter assay, in association with an increase in the ratio of [3H]leucine/[3H]thymidine uptake, indicating SMC hypertrophy. At 48 h, p21Waf1 expression was up-regulated in SMC exposed to AII but not in those exposed to serum. These results suggest that p21Waf1 may be involved in hypertrophy. To further investigate this issue, two manipulations of the p21Waf1 gene were performed. Adenovirus-mediated over-expression of p21Waf1 not only reduced S-phasic cells but also caused hypertrophy, despite the exposure to serum. Antisense oligodeoxynucleotide for p21Waf1 inhibited the hypertrophy of SMC exposed to AII. Our data suggest that p21Waf1 may play a role in SMC hypertrophy as well.

  5. Calcineurin A-β is required for hypertrophy but not matrix expansion in the diabetic kidney.

    PubMed

    Reddy, Ramesh N; Knotts, Taylor L; Roberts, Brian R; Molkentin, Jeffery D; Price, S Russ; Gooch, Jennifer L

    2011-02-01

    Calcineurin is an important signalling protein that regulates a number of molecular and cellular processes. Previously, we found that inhibition of calcineurin with cyclosporine reduced renal hypertrophy and blocked glomerular matrix expansion in the diabetic kidney. Isoforms of the catalytic subunit of calcineurin are reported to have tissue specific expression and functions. In particular, the β isoform has been implicated in cardiac and skeletal muscle hypertrophy. Therefore, we examined the role of calcineurin β in diabetic renal hypertrophy and glomerular matrix expansion. Type I diabetes was induced in wild-type and β(-/-) mice and then renal function, extracellular matrix expansion and hypertrophy were evaluated. The absence of β produced a significant decrease in total calcineurin activity in the inner medulla (IM) and reduced nuclear factor of activated T-cells (NFATc) activity. Loss of β did not alter diabetic renal dysfunction assessed by glomerular filtration rate, urine albumin excretion and blood urea nitrogen. Similarly, matrix expansion in the whole kidney and glomerulus was not different between diabetic wild-type and β(-/-) mice. In contrast, whole kidney and glomerular hypertrophy were significantly reduced in diabetic β(-/-) mice. Moreover, β(-/-) renal fibroblasts demonstrated impaired phosphorylation of Erk1/Erk2, c-Jun N-terminal kinases (JNK) and mammalian target of rapamycin (mTOR) following stimulation with transforming growth factor-β and did not undergo hypertrophy with 48 hrs culture in high glucose. In conclusion, loss of the β isoform of calcineurin is sufficient to reproduce beneficial aspects of cyclosporine on diabetic renal hypertrophy but not matrix expansion. Therefore, while multiple signals appear to regulate matrix, calcineurin β appears to be a central mechanism involved in organ hypertrophy.

  6. Calcineurin A-β is required for hypertrophy but not matrix expansion in the diabetic kidney

    PubMed Central

    Reddy, Ramesh N; Knotts, Taylor L; Roberts, Brian R; Molkentin, Jeffery D; Price, S Russ; Gooch, Jennifer L

    2011-01-01

    Abstract Calcineurin is an important signalling protein that regulates a number of molecular and cellular processes. Previously, we found that inhibition of calcineurin with cyclosporine reduced renal hypertrophy and blocked glomerular matrix expansion in the diabetic kidney. Isoforms of the catalytic subunit of calcineurin are reported to have tissue specific expression and functions. In particular, the β isoform has been implicated in cardiac and skeletal muscle hypertrophy. Therefore, we examined the role of calcineurin β in diabetic renal hypertrophy and glomerular matrix expansion. Type I diabetes was induced in wild-type and β−/− mice and then renal function, extracellular matrix expansion and hypertrophy were evaluated. The absence of β produced a significant decrease in total calcineurin activity in the inner medulla (IM) and reduced nuclear factor of activated T-cells (NFATc) activity. Loss of β did not alter diabetic renal dysfunction assessed by glomerular filtration rate, urine albumin excretion and blood urea nitrogen. Similarly, matrix expansion in the whole kidney and glomerulus was not different between diabetic wild-type and β−/− mice. In contrast, whole kidney and glomerular hypertrophy were significantly reduced in diabetic β−/− mice. Moreover, β−/− renal fibroblasts demonstrated impaired phosphorylation of Erk1/Erk2, c-Jun N-terminal kinases (JNK) and mammalian target of rapamycin (mTOR) following stimulation with transforming growth factor-β and did not undergo hypertrophy with 48 hrs culture in high glucose. In conclusion, loss of the β isoform of calcineurin is sufficient to reproduce beneficial aspects of cyclosporine on diabetic renal hypertrophy but not matrix expansion. Therefore, while multiple signals appear to regulate matrix, calcineurin β appears to be a central mechanism involved in organ hypertrophy. PMID:19778355

  7. Effect of miR-29a inhibition on ventricular hypertrophy induced by pressure overload.

    PubMed

    Han, Wei; Han, Yancong; Liu, Xiaokun; Shang, Xiaoming

    2015-03-01

    To investigate whether inhibition of miR-29a functioning prevents the hypertension-induced ventricular hypertrophy and fibrosis. Patients diagnosed with hypertension and left ventricular hypertrophy were recruited for the study. Serum levels of miR-29a were determined by RT-PCR. Levels of serum matrix metalloproteinase-9 (MMP-9), collagen type I and III (PINP and PIIINP) were determined by double-antibody enzyme-linked immunosorbent assay. Mouse model of transverse aortic constriction (TAC) was established. 7 days after surgery, TAC mice were injected intraperitoneally with antagomir miR-29a or vehicle once a day for 3 days. After 4 weeks of surgery, animals were sacrificed and cross-sections of the hearts were stained and evaluated for hypertrophy and fibrosis. The expression of the protein markers of hypertrophy and fibrosis was determined by immunoblotting. The serum level of miR-29a in hypertensive patients with left ventricular hypertrophy was significantly higher than those in patients with hypertension alone (p < 0.05). The levels of serum miR-29a were positively correlated with those of PINP, PIIINP, and MMP-9 (r = 0.58, 0.45, 0.66, respectively, p < 0.05). In mouse model of pressure overload, the antagomir miR-29a was found to significantly suppress the hypertrophy of cardiomyocytes and the expression of ANP and β-MHC, the hypertrophy indices. Also, the ventricular fibrosis and expression of the marker proteins were blocked in antagomir treated mice. The inhibition of miR-29a was found to be effective in improving the ventricular remodeling and hypertrophy caused by pressure overload.

  8. UCH-L1 induces podocyte hypertrophy in membranous nephropathy by protein accumulation.

    PubMed

    Lohmann, Frithjof; Sachs, Marlies; Meyer, Tobias N; Sievert, Henning; Lindenmeyer, Maja T; Wiech, Thorsten; Cohen, Clemens D; Balabanov, Stefan; Stahl, R A K; Meyer-Schwesinger, Catherine

    2014-07-01

    Podocytes are terminally differentiated cells of the glomerular filtration barrier that react with hypertrophy in the course of injury such as in membranous nephropathy (MGN). The neuronal deubiquitinase ubiquitin C-terminal hydrolase L1 (UCH-L1) is expressed and activated in podocytes of human and rodent MGN. UCH-L1 regulates the mono-ubiquitin pool and induces accumulation of poly-ubiquitinated proteins in affected podocytes. Here, we investigated the role of UCH-L1 in podocyte hypertrophy and in the homeostasis of the hypertrophy associated "model protein" p27(Kip1). A better understanding of the basic mechanisms leading to podocyte hypertrophy is crucial for the development of specific therapies in MGN. In human and rat MGN, hypertrophic podocytes exhibited a simultaneous up-regulation of UCH-L1 and of cytoplasmic p27(Kip1) content. Functionally, inhibition of UCH-L1 activity and knockdown or inhibition of UCH-L1 attenuated podocyte hypertrophy by decreasing the total protein content in isolated glomeruli and in cultured podocytes. In contrast, UCH-L1 levels and activity increased podocyte hypertrophy and total protein content in culture, specifically of cytoplasmic p27(Kip1). UCH-L1 enhanced cytoplasmic p27(Kip1) levels by nuclear export and decreased poly-ubiquitination and proteasomal degradation of p27(Kip1). In parallel, UCH-L1 increased podocyte turnover, migration and cytoskeletal rearrangement, which are associated with known oncogenic functions of cytoplasmic p27(Kip1) in cancer. We propose that UCH-L1 induces podocyte hypertrophy in MGN by increasing the total protein content through altered degradation and accumulation of proteins such as p27(Kip1) in the cytoplasm of podocytes. Modification of both UCH-L1 activity and levels could be a new therapeutic avenue to podocyte hypertrophy in MGN.

  9. Receptor binding and cell-mediated metabolism of (/sup 125/I)monoiodoglucagon by isolated canine hepatocytes

    SciTech Connect

    Hagopian, W.A.; Tager, H.S.

    1984-07-25

    A reverse-phase HPLC method has been developed to purify /sup 125/I-labeled products resulting from the chloramine-T-based iodination of glucagon. In addition the products ((/sup 125/I)iodoTyr/sup 10/ /sup 13/)glucagon, ((/sup 125/I)iodoTyr/sup 13/)glucagon, and ((/sup 125/I)iodoTyr/sup 10/)glucagon) have been used to study the receptor binding of glucagon and the cell-mediated metabolism of the hormone by isolated canine hepatocytes. It was concluded that (a) not withstanding apparent differences in affinities exhibited by the three peptides, the interactions with the glucagon receptor are functionally equivalent, and (b) the cell-mediated metabolism of receptor-bound glucagon involves the formation of hormone-derived peptides in which the biologically important NH/sub 2/-terminal region of the hormone has been modified by limited proteolytic cleavage.

  10. Syndecan-4 Signaling Is Required for Exercise-Induced Cardiac Hypertrophy

    PubMed Central

    Xie, Jun; He, Guixin; Chen, Qinhua; Sun, Jiayin; Dai, Qin; Lu, Jianrong; Li, Guannan; Wu, Han; Li, Ran; Chen, Jianzhou; Xu, Wei; Xu, Biao

    2016-01-01

    Cardiac hypertrophy can be broadly classified as either physiological or pathological. Physiological stimuli such as exercise cause adaptive cardiac hypertrophy and normal heart function. Pathological stimuli including hypertension and aortic valvular stenosis cause maladaptive cardiac remodeling and ultimately heart failure. Syndecan-4 (synd4) is a transmembrane proteoglycan identified as being involved in cardiac adaptation after injury, but whether it takes part in physiological cardiac hypertrophy is unclear. We observed upregulation of synd4 in exercise-induced hypertrophic myocardium. To evaluate the role of synd4 in the physiological form of cardiac hypertrophy, mice lacking synd4 (synd4–/–) were exercised by swimming for 4 wks. Ultrasonic cardiogram (UCG) and histological analysis revealed that swimming induced the hypertrophic phenotype but was blunted in synd4–/– compared with wild-type (WT) mice. The swimming-induced activation of Akt, a key molecule in physiological hypertrophy was also more decreased than in WT controls. In cultured cardiomyocytes, synd4 overexpression could induce cell enlargement, protein synthesis and distinct physiological molecular alternation. Akt activation also was observed in synd4-overexpressed cardiomyocytes. Furthermore, inhibition of protein kinase C (PKC) prevented the synd4-induced hypertrophic phenotype and Akt phosphorylation. This study identified an essential role of synd4 in mediation of physiological cardiac hypertrophy. PMID:26835698

  11. Homocysteine induces cardiac hypertrophy by up-regulating ATP7a expression

    PubMed Central

    Cao, Zhanwei; Zhang, Yanzhou; Sun, Tongwen; Zhang, Shuguang; Yu, Weiya; Zhu, Jie

    2015-01-01

    Aims: The aim of the study is to investigate the molecular mechanism by which homocysteine (Hcy) induces cardiac hypertrophy. Methods: Primary cardiomyocytes were obtained from baby Sprague-Dawley rats within 3 days after birth. Flow cytometry was used to measure cell sizes. Quantitative real-time polymerase chain reaction was performed to measure the expression of β-myosin heavy chain and atrial natriuretic peptide genes. Western blotting assay was employed to determine ATP7a protein expression. Cytochrome C oxidase (COX) activity test was used to evaluate the activity of COX. Atomic absorption spectroscopy was performed to determine copper content. siRNAs were used to target-silence the expression of ATP7a. Results: Hcy induced cardiac hypertrophy and increased the expression of cardiac hypertrophy-related genes. ATP7a was a key factor in cardiac hypertrophy induced by Hcy. Reduced ATP7a expression inhibited cardiac hypertrophy induced by Hcy. Elevated ATP7a expression induced by Hcy inhibited COX activity. Enhanced ATP7a expression inhibited COX activity by lowering intracellular copper content. Conclusions: Hcy elevates ATP7a protein expression, reduces copper content, and lowers COX activity, finally leading to cardiac hypertrophy. PMID:26722473

  12. Physiological activation of Akt by PHLPP1 deletion protects against pathological hypertrophy

    PubMed Central

    Moc, Courtney; Taylor, Amy E.; Chesini, Gino P.; Zambrano, Cristina M.; Barlow, Melissa S.; Zhang, Xiaoxue; Gustafsson, Åsa B.; Purcell, Nicole H.

    2015-01-01

    Aims To examine the role of physiological Akt signalling in pathological hypertrophy through analysis of PHLPP1 (PH domain leucine-rich repeat protein phosphatase) knock-out (KO) mice. Methods and results To investigate the in vivo requirement for ‘physiological’ control of Akt activation in cardiac growth, we examined the effect of deleting the Akt phosphatase, PHLPP, on the induction of cardiac hypertrophy. Basal Akt phosphorylation increased nearly two-fold in the cardiomyocytes from PHLPP1 KO mice and physiological hypertrophy induced by swimming exercise was accentuated as assessed by increased heart size and myocyte cell area. In contrast, the development of pathophysiological hypertrophy induced by pressure overload and assessed by increases in heart size, myocyte cell area, and hypertrophic gene expression was attenuated. This attenuation coincided with decreased fibrosis and cell death in the KO mice. Cast moulding revealed increased capillary density basally in the KO hearts, which was further elevated relative to wild-type mouse hearts in response to pressure overload. In vitro studies with isolated myocytes in co-culture also demonstrated that PHLPP1 deletion in cardiomyocytes can enhance endothelial tube formation. Expression of the pro-angiogenic factor VEGF was also elevated basally and accentuated in response to transverse aortic constriction in hearts from KO mice. Conclusion Our data suggest that enhancing Akt activity by inhibiting its PHLPP1-mediated dephosphorylation promotes processes associated with physiological hypertrophy that may be beneficial in attenuating the development of pathological hypertrophy. PMID:25411382

  13. Epigallocatechin-3 gallate prevents cardiac hypertrophy induced by pressure overload in rats.

    PubMed

    Hao, Jia; Kim, Chan-Hyung; Ha, Tae-Sun; Ahn, Hee-Yul

    2007-06-01

    Pressure overload diseases, such as valvular stenosis and systemic hypertension, manifest morphologically in patients as cardiac concentric hypertrophy. Prevention of cardiac remodeling due to increased pressure overload is important to reduce morbidity and mortality. Epigallocatechin-3 gallate (EGCG) is a major bioactive polyphenol present in green tea which has been found to be a nitric oxide-mediated vasorelaxant and to be cardioprotective in myocardial ischemia-reperfusion injury. Therefore, we investigated whether EGCG supplementation could reduce in vivo pressure overloadmediated cardiac hypertrophy. Cardiac hypertrophy was induced by suprarenal transverse abdominal aortic constriction (AC) in rats. Three weeks after AC surgery, heart to body weight ratio increased in the AC group by 34% compared to the sham group. EGCG administration suppressed the load-induced increase in heart weight by 69%. Attenuation of cardiac hypertrophy by EGCG was associated with attenuation of the increase in myocyte cell size and fibrosis induced by aortic constriction. Despite abolition of hypertrophy by EGCG, transstenotic pressure gradients did not change. Echocardiogram revealed that increased left ventricular systolic dimensions and deteriorated systolic function were relieved by EGCG. These results suggest that EGCG prevents the development of left ventricular concentric hypertrophy by pressure overload and may be a useful therapeutic modality to prevent cardiac remodeling in patients with pressure overload myocardial diseases.

  14. Cyclin D2 induces proliferation of cardiac myocytes and represses hypertrophy

    SciTech Connect

    Busk, Peter K. . E-mail: pkbu@novonordisk.com; Hinrichsen, Rebecca; Bartkova, Jirina; Hansen, Ane H.; Christoffersen, Tue E.H.; Bartek, Jiri; Haunso, Stig

    2005-03-10

    The myocytes of the adult mammalian heart are considered unable to divide. Instead, mitogens induce cardiomyocyte hypertrophy. We have investigated the effect of adenoviral overexpression of cyclin D2 on myocyte proliferation and morphology. Cardiomyocytes in culture were identified by established markers. Cyclin D2 induced DNA synthesis and proliferation of cardiomyocytes and impaired hypertrophy induced by angiotensin II and serum. At the molecular level, cyclin D2 activated CDK4/6 and lead to pRB phosphorylation and downregulation of the cell cycle inhibitors p21{sup Waf1/Cip1} and p27{sup Kip1}. Expression of the CDK4/6 inhibitor p16 inhibited proliferation and cyclin D2 overexpressing myocytes became hypertrophic under such conditions. Inhibition of hypertrophy by cyclin D2 correlated with downregulation of p27{sup Kip1}. These data show that hypertrophy and proliferation are highly related processes and suggest that cardiomyocyte hypertrophy is due to low amounts of cell cycle activators unable to overcome the block imposed by cell cycle inhibitors. Cell cycle entry upon hypertrophy may be converted to cell division by increased expression of activators such as cyclin D2.

  15. The effects of eccentric and concentric training at different velocities on muscle hypertrophy.

    PubMed

    Farthing, Jonathan P; Chilibeck, Philip D

    2003-08-01

    The purpose of this study was to examine the effect of isokinetic eccentric (ECC) and concentric (CON) training at two velocities [fast, 180 degrees s(-1 )(3.14 rad s(-1)) and slow,30 degrees s(-1)(0.52 rad s(-1))] on muscle hypertrophy. Twenty-four untrained volunteers (age 18-36 years) participated in fast- ( n=13) or slow- ( n=11) velocity training, where they trained one arm eccentrically for 8 weeks followed by CON training of the opposite arm for 8 weeks. Ten subjects served as controls (CNT). Subjects were tested before and after training for elbow flexor muscle thickness by sonography and isokinetic strength (Biodex). Overall, ECC training resulted in greater hypertrophy than CON training (P<0.01). No significant strength or hypertrophy changes occurred in the CNT group. ECC (180 degrees s(-1)) training resulted in greater hypertrophy than CON (180 degrees s(-1)) training and CON (30 degrees s(-1)) training (P<0.01). ECC (30 degrees s(-1)) training resulted in greater hypertrophy than CON (180 degrees s(-1)) training (P<0.05), but not CON (30 degrees s(-1)) training. ECC (180 degrees s(-1)) training resulted in the greatest increases in strength (P<0.01). We conclude that ECC fast training is the most effective for muscle hypertrophy and strength gain.

  16. G protein-coupled receptor 56 regulates mechanical overload-induced muscle hypertrophy.

    PubMed

    White, James P; Wrann, Christiane D; Rao, Rajesh R; Nair, Sreekumaran K; Jedrychowski, Mark P; You, Jae-Sung; Martínez-Redondo, Vicente; Gygi, Steven P; Ruas, Jorge L; Hornberger, Troy A; Wu, Zhidan; Glass, David J; Piao, Xianhua; Spiegelman, Bruce M

    2014-11-04

    Peroxisome proliferator-activated receptor gamma coactivator 1-alpha 4 (PGC-1α4) is a protein isoform derived by alternative splicing of the PGC1α mRNA and has been shown to promote muscle hypertrophy. We show here that G protein-coupled receptor 56 (GPR56) is a transcriptional target of PGC-1α4 and is induced in humans by resistance exercise. Furthermore, the anabolic effects of PGC-1α4 in cultured murine muscle cells are dependent on GPR56 signaling, because knockdown of GPR56 attenuates PGC-1α4-induced muscle hypertrophy in vitro. Forced expression of GPR56 results in myotube hypertrophy through the expression of insulin-like growth factor 1, which is dependent on Gα12/13 signaling. A murine model of overload-induced muscle hypertrophy is associated with increased expression of both GPR56 and its ligand collagen type III, whereas genetic ablation of GPR56 expression attenuates overload-induced muscle hypertrophy and associated anabolic signaling. These data illustrate a signaling pathway through GPR56 which regulates muscle hypertrophy associated with resistance/loading-type exercise.

  17. Adenotonsillar hypertrophy as a risk factor of dentofacial abnormality in Korean children.

    PubMed

    Kim, Dong-Kyu; Rhee, Chae Seo; Yun, Pil-Young; Kim, Jeong-Whun

    2015-11-01

    No studies for the role of adenotonsillar hypertrophy in development of dentofacial abnormalities have been performed in Asian pediatric population. Thus, we aimed to investigate the relationship between adenotonsillar hypertrophy and dentofacial abnormalities in Korean children. The present study included consecutive children who visited a pediatric clinic for sleep-disordered breathing due to habitual mouth breathing, snoring or sleep apnea. Their palatine tonsils and adenoids were graded by oropharyngeal endoscopy and lateral cephalometry. Anterior open bite, posterior crossbite, and Angle's class malocclusions were evaluated for dentofacial abnormality. The receiver-operating characteristic curve analysis was used to identify age cutoffs to predict dentofacial abnormality. A total of 1,083 children were included. The presence of adenotonsillar hypertrophy was significantly correlated with the prevalence of dentofacial abnormality [adjusted odds ratio = 4.587, 95% CI (2.747-7.658)] after adjusting age, sex, body mass index, allergy, and Korean version of obstructive sleep apnea-18 score. The cutoff age associated with dentofacial abnormality was 5.5 years (sensitivity = 75.5%, specificity = 67%) in the children with adenotonsillar hypertrophy and 6.5 years (sensitivity = 70.6%, specificity = 57%) in those without adenotonsillar hypertrophy. In conclusion, adenotonsillar hypertrophy may be a risk factor for dentofacial abnormalities in Korean children and early surgical intervention could be considered with regards to dentofacial abnormality.

  18. A chloride current component induced by hypertrophy in rat ventricular myocytes.

    PubMed

    Bénitah, J P; Gómez, A M; Delgado, C; Lorente, P; Lederer, W J

    1997-05-01

    The effect of hypertrophy on membrane currents of rat left ventricular myocytes was studied with the whole cell voltage-clamp method. We found that the slope of the total time-independent current density-voltage relationship was increased in hypertrophied cells. No change in the zero-current potential was observed. Surprisingly, the dominant time-independent current, the inward rectifier K+ current (measured as the Ba(2+)-sensitive current density) was unchanged. We therefore investigated the identity of the outwardly rectifying Ba(2+)-resistant current seen in the hypertrophied rat ventricular myocytes but not present in control cells. We found that this current 1) was not carried by monovalent cations, 2) was partially blocked by anthracene-9-carboxylic acid (9-AC), and 3) was sensitive to variations in extracellular Cl concentration. These findings are consistent with the current being carried at least partially by Cl-. The presence of an additional Cl(-)-dependent component in hypertrophied cells is supported by the actions of 9-AC on the measured action potentials (APs). 9-AC had no effect on control cells APs but prolonged hypertrophied cell APs. We conclude that a Cl- current component develops in hypertrophied rat heart cells. This component appears to shorten the AP duration and might thus provide protection from cardiac arrhythmias.

  19. The effect of inter-set rest intervals on resistance exercise-induced muscle hypertrophy.

    PubMed

    Henselmans, Menno; Schoenfeld, Brad J

    2014-12-01

    Due to a scarcity of longitudinal trials directly measuring changes in muscle girth, previous recommendations for inter-set rest intervals in resistance training programs designed to stimulate muscular hypertrophy were primarily based on the post-exercise endocrinological response and other mechanisms theoretically related to muscle growth. New research regarding the effects of inter-set rest interval manipulation on resistance training-induced muscular hypertrophy is reviewed here to evaluate current practices and provide directions for future research. Of the studies measuring long-term muscle hypertrophy in groups employing different rest intervals, none have found superior muscle growth in the shorter compared with the longer rest interval group and one study has found the opposite. Rest intervals less than 1 minute can result in acute increases in serum growth hormone levels and these rest intervals also decrease the serum testosterone to cortisol ratio. Long-term adaptations may abate the post-exercise endocrinological response and the relationship between the transient change in hormonal production and chronic muscular hypertrophy is highly contentious and appears to be weak. The relationship between the rest interval-mediated effect on immune system response, muscle damage, metabolic stress, or energy production capacity and muscle hypertrophy is still ambiguous and largely theoretical. In conclusion, the literature does not support the hypothesis that training for muscle hypertrophy requires shorter rest intervals than training for strength development or that predetermined rest intervals are preferable to auto-regulated rest periods in this regard.

  20. Effect of Culture Time on the Basal Expression Levels of Drug Transporters in Sandwich-Cultured Primary Rat HepatocytesS⃞

    PubMed Central

    Houghton, Jessica S.; Uyeda, Craig; Grillo, Mark P.; Jin, Lixia

    2011-01-01

    Sandwich-cultured rat hepatocytes are used in drug discovery for pharmacological and toxicological assessment of drug candidates, yet their utility as a functional model for drug transporters has not been fully characterized. To evaluate the system as an in vitro model for drug transport, expression changes of hepatic transporters relative to whole liver and freshly isolated hepatocytes (day 0) were examined by real-time quantitative reverse transcription-polymerase chain reaction for 4 consecutive days of culture. No significant differences in transporter expression levels were observed between freshly isolated hepatocytes and whole liver. Two distinct mRNA profiles were detected over time showing 1) a more than 5-fold decline in levels of uptake transporters such as Na+-taurocholate cotransporting polypeptide (Ntcp), organic anion transporter (Oat) 2, organic anion-transporting polypeptide (Oatp) 1a1, Oatp1a4, and Oatp1b2 and 2) a greater than 5-fold increase of efflux transporters P-glycoprotein (P-gp), breast cancer resistance protein (Bcrp), and multidrug resistance-related proteins (Mrp) 1, 2, 3, and 4. In addition, protein levels and functional activities for selected transporters were also determined. Protein levels for Mrp2, Bcrp, P-gp, Ntcp, and Oatp1a4 corresponded to changes in mRNA. Functional activities of Oatps and Oct1 exhibited a 3- and 4-fold decrease on day 2 and day 4, respectively, relative to that on day 0, whereas a more than 10-fold reduction in Oat2 activity was observed. These results indicate that the cell culture conditions used herein did not provide an optimal environment for expression of all hepatic transporters. Significant time-dependent alterations in basal gene expression patterns of transporters were detected compared with those in liver or freshly isolated hepatocytes. Further work and new strategies are required to improve the validity of this model as an in vitro tool for in vivo drug transport or biliary clearance prediction

  1. Predictions of cytochrome P450-mediated drug-drug interactions using cryopreserved human hepatocytes: comparison of plasma and protein-free media incubation conditions.

    PubMed

    Mao, Jialin; Mohutsky, Michael A; Harrelson, John P; Wrighton, Steven A; Hall, Stephen D

    2012-04-01

    Cryopreserved human hepatocytes suspended in human plasma (HHSHP) have previously provided accurate CYP3A drug-drug interaction (DDI) predictions from a single IC(50) that captures both reversible and time-dependent inhibition. The goal of this study was to compare the accuracy of DDI predictions by a protein-free human hepatocyte system combined with the fraction unbound in plasma for inhibitor(s) with those obtained with protein-containing incubations. Seventeen CYP3A, CYP2C9, or CYP2D6 inhibitors were incubated with hepatocytes in human plasma or hepatocyte maintenance medium (HMM) for 20 min over a range of concentrations after which midazolam 1'-hydroxylation, diclofenac 4'-hydroxylation or (R)-bufuralol 1'-hydroxylation were used to quantify the corresponding cytochrome P450 (P450) catalytic activities. Two methods were used to predict the human exposure ratio of the victim drug in the presence and absence of inhibitor. The HMM K(i, app) values were combined with the free average systemic plasma concentration ("free [I] with HMM K(i, app)") and the plasma K(i, app) values were combined with the total average systemic plasma concentration ("total [I] with plasma K(i, app)"). Of 63 clinical DDI studies, the total [I] with plasma K(i, app) method predicted 89% of cases within 2-fold of the reported interaction whereas the free [I] with HMM K(i, app) method predicted only 59%. There was a general underprediction by the free [I] with HMM K(i, app) method, which is consistent with an underestimation of in vitro inhibition potency in this system. In conclusion, the HHSHP system proved to be a simple, accurate predictor of DDIs for three major P450s and superior to the protein-free approach.

  2. A whole-cell and single-channel study of the voltage-dependent outward potassium current in avian hepatocytes

    PubMed Central

    1988-01-01

    Voltage-dependent membrane currents were studied in dissociated hepatocytes from chick, using the patch-clamp technique. All cells had voltage-dependent outward K+ currents; in 10% of the cells, a fast, transient, tetrodotoxin-sensitive Na+ current was identified. None of the cells had voltage-dependent inward Ca2+ currents. The K+ current activated at a membrane potential of about -10 mV, had a sigmoidal time course, and did not inactivate in 500 ms. The maximum outward conductance was 6.6 +/- 2.4 nS in 18 cells. The reversal potential, estimated from tail current measurements, shifted by 50 mV per 10-fold increase in the external K+ concentration. The current traces were fitted by n2 kinetics with voltage-dependent time constants. Omitting Ca2+ from the external bath or buffering the internal Ca2+ with EGTA did not alter the outward current, which shows that Ca2+-activated K+ currents were not present. 1-5 mM 4-aminopyridine, 0.5-2 mM BaCl2, and 0.1-1 mM CdCl2 reversibly inhibited the current. The block caused by Ba was voltage dependent. Single-channel currents were recorded in cell- attached and outside-out patches. The mean unitary conductance was 7 pS, and the channels displayed bursting kinetics. Thus, avian hepatocytes have a single type of K+ channel belonging to the delayed rectifier class of K+ channels. PMID:2453605

  3. Silica nanoparticles induce autophagy dysfunction via lysosomal impairment and inhibition of autophagosome degradation in hepatocytes

    PubMed Central

    Wang, Ji; Yu, Yongbo; Lu, Ke; Yang, Man; Li, Yang; Zhou, Xianqing; Sun, Zhiwei

    2017-01-01

    Autophagy dysfunction is considered as a potential toxic mechanism of nanomaterials. Silica nanoparticles (SiNPs) can induce autophagy, but the specific mechanism involved remains unclear. Therefore, the aim of this study was to confirm the effects of SiNPs on autophagy dysfunction and explore the possible underlying mechanism. In this article, we reported that cell-internalized SiNPs exhibited dose- and time-dependent cytotoxicity in both L-02 and HepG2 cells. Multiple methods verified that SiNPs induced autophagy even at the noncytotoxic level and blocked the autophagic flux at the high-dose level. Notably, SiNPs impaired the lysosomal function through damaging lysosomal ultrastructures, increasing membrane permeability, and downregulating the expression of lysosomal proteases, cathepsin B, as evidenced by transmission electron microscopy, acridine orange staining, quantitative reverse transcription-polymerase chain reaction, and Western blot assays. Collectively, these data concluded that SiNPs inhibited autophagosome degradation via lysosomal impairment in hepatocytes, resulting in autophagy dysfunction. The current study not only discloses a potential mechanism of autophagy dysfunction induced by SiNPs but also provides novel evidence for the study of toxic effect and safety evaluation of SiNPs. PMID:28182147

  4. Hepatocyte Lysosomal Membrane Stabilization by Olive Leaves against Chemically Induced Hepatocellular Neoplasia in Rats

    PubMed Central

    Abdel-Hamid, N. M.; El-Moselhy, M. A.; El-Baz, A.

    2011-01-01

    Extensive efforts are exerted looking for safe and effective chemotherapy for hepatocellular carcinoma (HCC). Specific and sensitive early biomarkers for HCC still in query. Present work to study proteolytic activity and lysosomal membrane integrity by hepatocarcinogen, trichloroacetic acid (TCA), in Wistar rats against aqueous olive leaf extract (AOLE).TCA showed neoplastic changes as oval- or irregular-shaped hepatocytes and transformed, vesiculated, and binucleated liver cells. The nuclei were pleomorphic and hyperchromatic. These changes were considerably reduced by AOLE. The results added, probably for the first time, that TCA-induced HCC through disruption of hepatocellular proteolytic enzymes as upregulation of papain, free cathepsin-D and nonsignificant destabilization of lysosomal membrane integrity, a prerequisite for cancer invasion and metastasis. AOLE introduced a promising therapeutic value in liver cancer, mostly through elevating lysosomal membrane integrity. The study substantiated four main points: (1) the usefulness of proteolysis and lysosomalmembrane integrity in early prediction of HCC. (2) TCA carcinogenesis is possibly mediated by lysosomal membrane destabilization, through cathepsin-D disruption, which could be reversed by AOLE administration. (3) A new strategy for management of HCC, using dietary olive leaf system may be a helpful phytotherapeutic trend. (4) A prospective study on serum proteolytic enzyme activity may introduce novel diagnostic tools. PMID:21994869

  5. Mitochondrial DNA from hepatocytes as a ligand for TLR9: Drivers of nonalcoholic steatohepatitis?

    PubMed Central

    Handa, Priya; Vemulakonda, Akhila; Kowdley, Kris V; Uribe, Misael; Méndez-Sánchez, Nahum

    2016-01-01

    Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide, affecting approximately one third of the Western world. It consists of a wide spectrum of liver disorders, ranging from fatty liver to nonalcoholic steatohepatitis (NASH), which consists of steatosis, ballooning injury and inflammation. Despite an alarming growth in the statistics surrounding NAFLD, there are as yet no effective therapies for its treatment. Innate immune signaling has been thought to play a significant role in initiating and augmenting hepatic inflammation, contributing to the transition from nonalcoholic fatty liver to NASH. An immune response is triggered by countless signals called damage-associated molecular patterns (DAMPs) elicited by lipid-laden and damaged hepatocytes, which are recognized by pattern recognition receptors (PRRs) on hepatic immune cells to initiate inflammatory signaling. In this editorial, in addition to summarizing innate immune signaling in NAFLD and discussing potential therapies that target innate immune pathways, we have described a recent study that demonstrated that mitochondrial DNA serves as a DAMP activating a hepatic PRR, TLR9, in mice and in the plasma of NASH patients. In addition to identifying a new ligand for TLR9 during NASH progression, the study shows that blocking TLR9 reverses NASH, paving the way for the development of future NASH therapy. PMID:27610009

  6. Hepatocyte growth factor plays a dual role in regulating skeletal muscle satellite cell proliferation and differentiation.

    PubMed

    Gal-Levi, R; Leshem, Y; Aoki, S; Nakamura, T; Halevy, O

    1998-03-12

    The role of hepatocyte growth factor (HGF) and its receptor, c-met, in proliferation and differentiation of satellite cells was studied in primary cultures of chicken skeletal muscle satellite cells and a myogenic C2 cell line. HGF mRNA was expressed mainly in the myotubes of both cultures. The addition of conditioned medium derived from those cultures had a scattering effect on the canine kidney epithelial cell line, MDCK. In contrast, c-met mRNA levels decreased during cell differentiation of C2 and primary satellite cells. Application of exogenous HGF to chicken myoblasts resulted in their enhanced DNA synthesis. Among several growth factors, HGF was the first to induce DNA synthesis in quiescent satellite cells, thereby driving them into the cell cycle. Ectopic expression of chicken HGF in primary satellite cells suppressed the activation of muscle-regulatory gene reporter constructs MCK-CAT, MRF4-CAT, MEF2-CAT and 4Rtk-CAT, as well as the gene expression of MyoD and myogenin, and MHC protein expression. Ectopic MyoD reversed HGF's inhibitory effect on MCK transactivation. These data suggest that HGF inhibits cell differentiation by inhibiting the activity of basic helix-loop-helix (bHLH)/E protein heterodimers, thus inhibiting myogenic determination factor activity and subsequent muscle-specific protein expression. During muscle growth and regeneration, HGF plays a dual role in satellite-cell myogenesis, affecting both the proliferation and differentiation of these cells in a paracrine fashion.

  7. Effect of carbohydrates attached to polystyrene on hepatocyte morphology on sugar-derivatized polystyrene matrices.

    PubMed

    Kim, Sang-Heon; Hoshiba, Takashi; Akaike, Toshihiro

    2003-12-15

    Sugar-carrying polymers have been utilized as artificial matrices for cell adhesion in tissue engineering. We have developed sugar-derivatized polystyrenes (PV-sugars) as artificial matrices, which control hepatocyte adhesion and hepatic function. Hepatocytes adhere to PV-sugar matrices in a receptor-mediated manner. In this study, we designed a new galactose-derivatized PV-sugar, poly-(6-O-p-vinylbenzyl-alpha-D-galactose) (PV6Gal) and evaluated the role of carbohydrate attached to polystyrene (PS) backbone in the morphological difference of hepatocyte cultured on PV-sugar matrices. Hepatocytes spread on monosaccharide-derivatized PV-sugars but not on disaccharide-derivatized PV-sugars. The actin filament remained aggregated in the central area of the cell body on disaccharide-derivatized PV-sugars. Hepatocyte cell bodies fully were spread on collagen, and the actin filament was almost completely reorganized. Hepatocyte spreading on monosaccharide-derivatized PV-sugars, however, was caused by protrusive cell-matrix contact like lamellipodia and the actin filament was not completely reorganized. This indicated that hepatocyte spreading on PV-sugar matrices was restricted compared with ECM-mediated cell spreading. In addition, typical spheroid formation of hepatocytes was promoted on disaccharide-derivatized PV-sugars compared with monosaccharide-derivatized PV-sugars. Although hepatocytes adhered with different affinities to PV-sugar matrices, hepatocyte morphology was not affected by the adhesion affinity. We suggest that the type of carbohydrate attached to the PS backbone governs the morphology of hepatocyte cultured on PV-sugar matrices.

  8. Allicin Modulates the Antioxidation and Detoxification Capabilities of Primary Rat Hepatocytes

    PubMed Central

    Wu, Chih-Chung; Chu, Yung-Lin; Sheen, Lee-Yan

    2012-01-01

    The effect of allicin, an active ingredient of garlic, on lactate dehydrogenase (LDH) leakage, lipid peroxidation, glutathione (GSH) content, and GSH-related enzyme activity was investigated in primary hepatocytes. In this study, allicin was synthesized in our laboratory as an experimental material, and primary hepatocytes isolated from Sprague-Dawley rats were used as an experimental model. According to the results, hepatocytes treated with 10 μM allicin did not differ from the control on LDH leakage during various incubation times. When the hepatocytes were treated with 10 μM allicin, their levels of thiobarbituric acid reactive-substances (TBARS) did not differ significantly from that of the control within the 8-h incubation. However, the TBARS values of hepatocytes treated with 30 and 50 μM allicin were higher compared to the control after incubation for 4 h and 8 h, respectively. The hepatocyte intracellular GSH content was significantly higher than that of the control after 30 μM allicin treatment, but treatment with 50 μM allicin caused a significant GSH depletion after incubation for 4 h or longer. In addition, when hepatocytes were treated for 24 h with 10 or 30 μM allicin, glutathione peroxidase (GPx) activity was significantly increased compared to that of the control, whereas 50 μM allicin treatment for 24 h or longer significantly decreased the GPx activity. Glutathione reductase (GRd) activity was significantly increased when the hepatocytes were treated with 10 μM allicin for 24 h, but GRd activity significantly decreased when the hepatocytes were treated with 50 μM allicin. However, hepatocytes treated for 24 h with 10 or 30 μM allicin showed significantly increased glutathione S-transferase (GST) activity compared to the control. These results suggest that 10 μM allicin potentially enhances the antioxidation and detoxification capabilities of primary rat hepatocytes. PMID:24716147

  9. The eyeglass reversal.

    PubMed

    Oh, Songjoo

    2011-07-01

    Some figures, such as the Necker cube, are spontaneously reversible between alternative percepts. Before learning those skilled reversals, how do people achieve reversals for the very first time? It has been known that, in the case of a first reversal, people can be expected to see the reversal when given specific information about how the figures are ambiguous. This point was confirmed by using drawing versions of reversible figures. To demonstrate how intention plays a role in the initial reversal of a real object, a pair of regular eyeglasses, reversible in perspective, were presented to naïve observers in monocular vision. When the eyeglasses were viewed inwardly and the observers were given information that the eyeglasses could be ambiguous, they were able to easily see the reversal. When the eyeglasses were viewed outwardly, observers saw it only after they had been informed of exactly what the two alternative percepts were.Interestingly, many observers often mistakenly saw the inwardly viewed eyeglasses as placed outwardly from the beginning of the observation, while they saw the outwardly viewed eyeglasses correctly. Taking these results together, for the first reversal of a real object, the specificity of intention varies with the ambiguity of the object.

  10. Curcumin inhibits activation of TRPM2 channels in rat hepatocytes

    PubMed Central

    Kheradpezhouh, E.; Barritt, G.J.; Rychkov, G.Y.

    2015-01-01

    Oxidative stress is a hallmark of many liver diseases including viral and drug-induced hepatitis, ischemia-reperfusion injury, and non-alcoholic steatohepatitis. One of the consequences of oxidative stress in the liver is deregulation of Ca2+ homeostasis, resulting in a sustained elevation of the free cytosolic Ca2+ concentration ([Ca2+]c) in hepatocytes, which leads to irreversible cellular damage. Recently it has been shown that liver damage induced by paracetamol and subsequent oxidative stress is, in large part, mediated by Ca2+ entry through Transient Receptor Potential Melastatin 2 (TRPM2) channels. Involvement of TRPM2 channels in hepatocellular damage induced by oxidative stress makes TRPM2 a potential therapeutic target for treatment of a range of oxidative stress-related liver diseases. We report here the identification of curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), a natural plant-derived polyphenol in turmeric spice, as a novel inhibitor of TRPM2 channel. Presence of 5 µM curcumin in the incubation medium prevented the H2O2- and paracetamol-induced [Ca2+]c rise in rat hepatocytes. Furthermore, in patch clamping experiments incubation of hepatocytes with curcumin inhibited activation of TRPM2 current by intracellular ADPR with IC50 of approximately 50 nM. These findings enhance understanding of the actions of curcumin and suggest that the known hepatoprotective properties of curcumin are, at least in part, mediated through inhibition of TRPM2 channels. PMID:26609559

  11. Protective effects of Salvia plebeia compound homoplantaginin on hepatocyte injury.

    PubMed

    Qu, Xian-Jun; Xia, Xue; Wang, Yuan-Shu; Song, Mei-Juan; Liu, Li-Li; Xie, Yan-Ying; Cheng, Yan-Na; Liu, Xiang-Juan; Qiu, Lu-Lu; Xiang, Lan; Gao, Jian-Jun; Zhang, Xiao-Fan; Cui, Shu-Xiang

    2009-07-01

    Salvia plebeia R. Br is a traditional Chinese herb which has been considered as an inflammatory mediator used for treatment of many infectious diseases including hepatitis. Previously, the compound homoplantaginin was isolated in our group. Hence, we evaluated the protective effects of homoplantaginin on hepatocyte injury. Homoplantaginin displayed an antioxidant property in a cell-free system and showed IC(50) of reduction level of DPPH radical at 0.35 microg/ml. In human hepatocyte HL-7702 cells exposed to H(2)O(2), the addition of 0.1-100 microg/ml of homoplantaginin, which did not have a toxic effect on cell viability, significantly reduced lactate dehydrogenase (LDH) leakage, and increased glutathione (GSH), glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in supernatant. In vivo assay, we employed the model of Bacillus Calmette-Guérin (BCG)/lipopolysaccharide (LPS)-induced hepatic injury mice to evaluate efficacy of homoplantaginin. Homoplantaginin (25-100mg/kg) significantly reduced the increase in serum alanine aminotranseferase (ALT) and aspartate aminotransferase (AST), decreased the levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 (IL-1). The same treatment also reduced the content of thiobarbituric acid-reactive substances (TBARS), elevated the levels of GSH, GSH-Px and SOD in hepatic homogenate. The histopathological analysis showed that the grade of liver injury was ameliorated with reduction of inflammatory cells and necrosis of liver cells in homoplantaginin treatment mice. These results suggest that homoplantaginin has a protective and therapeutic effect on hepatocyte injury, which might be associated with its antioxidant properties.

  12. Curcumin inhibits activation of TRPM2 channels in rat hepatocytes.

    PubMed

    Kheradpezhouh, E; Barritt, G J; Rychkov, G Y

    2016-04-01

    Oxidative stress is a hallmark of many liver diseases including viral and drug-induced hepatitis, ischemia-reperfusion injury, and non-alcoholic steatohepatitis. One of the consequences of oxidative stress in the liver is deregulation of Ca(2+) homeostasis, resulting in a sustained elevation of the free cytosolic Ca(2+) concentration ([Ca(2+)]c) in hepatocytes, which leads to irreversible cellular damage. Recently it has been shown that liver damage induced by paracetamol and subsequent oxidative stress is, in large part, mediated by Ca(2+) entry through Transient Receptor Potential Melastatin 2 (TRPM2) channels. Involvement of TRPM2 channels in hepatocellular damage induced by oxidative stress makes TRPM2 a potential therapeutic target for treatment of a range of oxidative stress-related liver diseases. We report here the identification of curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), a natural plant-derived polyphenol in turmeric spice, as a novel inhibitor of TRPM2 channel. Presence of 5µM curcumin in the incubation medium prevented the H2O2- and paracetamol-induced [Ca(2+)]c rise in rat hepatocytes. Furthermore, in patch clamping experiments incubation of hepatocytes with curcumin inhibited activation of TRPM2 current by intracellular ADPR with IC50 of approximately 50nM. These findings enhance understanding of the actions of curcumin and suggest that the known hepatoprotective properties of curcumin are, at least in part, mediated through inhibition of TRPM2 channels.

  13. Effects of ethanol on antioxidant capacity in isolated rat hepatocytes

    PubMed Central

    Yang, Sien-Sing; Huang, Chi-Chang; Chen, Jiun-Rong; Chiu, Che-Lin; Shieh, Ming-Jer; Lin, Su-Jiun; Yang, Suh-Ching

    2005-01-01

    AIM: To investigate dose-response and time-course of the effects of ethanol on the cell viability and antioxidant capacity in isolated rat hepatocytes. METHODS: Hepatocytes were isolated from male adult Wistar rats and seeded into 100-mm dishes. Hepatocytes were treated with ethanol at concentrations between 0 (C), 10 (E10), 50 (E50), and 100 (E100) mmol/L (dose response) for 12, 24, and 36 h (time course). Then, lactate dehydrogenase (LDH) leakage, malondialdehyde (MDA) concentration, glutathione (GSH) level, and activities of glutathione peroxidase (GPX), glutathione reductase (GRD), superoxide dismutase (SOD), and catalase (CAT) were measured. RESULTS: Our data revealed that LDH leakage was significantly increased by about 30% in group E100 over those in groups C and E10 at 24 and 36 h, The MDA concentration in groups C, E10 and E50 were significantly lower than that in group E100 at 36 h. Furthermore, the concentration of MDA in group E100 at 36 h was significantly higher by 4.5- and 1.7-fold, respectively, than that at 12 and 24 h. On the other hand, the GSH level in group E100 at 24 and 36 h was significantly decreased, by 32% and 28%, respectively, compared to that at 12 h. The activities of GRD and CAT in group E100 at 36 h were significantly less than those in groups C and E10. However, The GPX and SOD activities showed no significant change in each group. CONCLUSION: These results suggest that long-time incubation with higher concentration of ethanol (100 mmol/L) decreased the cell viability by means of reducing GRD and CAT activities and increasing lipid peroxidation. PMID:16437627

  14. Mitochondrial metabolic adaptation in right ventricular hypertrophy and failure

    PubMed Central

    Piao, Lin; Marsboom, Glenn

    2011-01-01

    Right ventricular failure (RVF) is the leading cause of death in pulmonary arterial hypertension (PAH). Some patients with pulmonary hypertension are adaptive remodelers and develop RV hypertrophy (RVH) but retain RV function; others are maladaptive remodelers and rapidly develop RVF. The cause of RVF is unclear and understudied and most PAH therapies focus on regressing pulmonary vascular disease. Studies in animal models and human RVH suggest that there is reduced glucose oxidation and increased glycolysis in both adaptive and maladaptive RVH. The metabolic shift from oxidative mitochondrial metabolism to the less energy efficient glycolytic metabolism may reflect myocardial ischemia. We hypothesize that in maladaptive RVH a vicious cycle of RV ischemia and transcription factor activation causes a shift from oxidative to glycolytic metabolism thereby ultimately promoting RVF. Interrupting this cycle, by reducing ischemia or enhancing glucose oxidation, might be therapeutic. Dichloroacetate, a pyruvate dehydrogenase kinase inhibitor, has beneficial effects on RV function and metabolism in experimental RVH, notably improving glucose oxidation and enhancing RV function. This suggests the mitochondrial dysfunction in RVH may be amenable to therapy. In this mini review, we describe the role of impaired mitochondrial metabolism in RVH, using rats with adaptive (pulmonary artery banding) or maladaptive (monocrotaline-induced pulmonary hypertension) RVH as models of human disease. We will discuss the possible mechanisms, relevant transcriptional factors, and the potential of mitochondrial metabolic therapeutics in RVH and RVF. PMID:20820751

  15. Limited myocardial perfusion reserve in patients with left ventricular hypertrophy

    SciTech Connect

    Goldstein, R.A.; Haynie, M. )

    1990-03-01

    Experimental studies in animals have suggested that coronary flow reserve may be limited in patients with left ventricular hypertrophy (LVH). Accordingly, to noninvasively determine the effect of LVH on myocardial perfusion reserve, 25 patients, 9 with LVH and 16 controls, underwent positron imaging with rubidium-82 (82Rb) (30-55 mCi) or nitrogen-13 (13N) ammonia (12-19 mCi) at rest and following intravenous dipyridamole and handgrip stress. LVH was documented by echocardiographic and/or electrocardiographic measurements. LVH patients had either no chest pain (n = 8) and/or a normal coronary angiogram (n = 6). Nine simultaneous transaxial images were acquired, and the mean ratio of stress to rest activity (S:R), based on all regions for each heart, was calculated as an estimate of myocardial perfusion reserve. There were no regional differences in activity (i.e., perfusion defects) in any of the studies. S:R averaged 1.41 +/- 0.10 (s.d.) for controls and 1.06 +/- 0.09 for patients with LVH (p less than 0.0001). These data provide support for an abnormality in perfusion reserve in patients with LVH.

  16. Cardiac hypertrophy in chick embryos induced by hypothermia

    SciTech Connect

    Boehm, C.; Johnson, T.R.; Caston, J.D.; Przybylski, R.J.

    1987-01-01

    A decrease in incubation temperature from 38 to 32/sup 0/C elicits a decrease in chicken embryo size and weight with concomitant heart enlargement if done after day 10 of incubation. When assayed at day 18 of incubation with the hypothermia started on day 11 or 14, evidence is presented that the heart enlargement is an hypertrophy with no detectable hyperplasia. Supporting data are presented for various physical parameters showing increases in heart wet and dry weight, volume, area, wall thickness, and cell size. There was little difference in DNA content and nuclear (/sup 3/H)thymidine labeling index between hearts of control and hypothermic embryos. Hearts of hypothermic embryos showed a slight increase in water content and considerable increases in RNA, protein, and glycogen content per unit DNA. The average size of polysomes isolated from hypothermic hearts was larger than that of polysomes isolated from controls. Microscopic studies showed no obvious increase in amount of capillary beds, connective tissue, and myocardial cells. Annulate lamellae were found only in myocardial cells of hypothermic embryos in sparse amounts and low frequency but always associated with large deposits of glycogen.

  17. Integrin activation and focal complex formation in cardiac hypertrophy

    NASA Technical Reports Server (NTRS)

    Laser, M.; Willey, C. D.; Jiang, W.; Cooper, G. 4th; Menick, D. R.; Zile, M. R.; Kuppuswamy, D.

    2000-01-01

    Cardiac hypertrophy is characterized by both remodeling of the extracellular matrix (ECM) and hypertrophic growth of the cardiocytes. Here we show increased expression and cytoskeletal association of the ECM proteins fibronectin and vitronectin in pressure-overloaded feline myocardium. These changes are accompanied by cytoskeletal binding and phosphorylation of focal adhesion kinase (FAK) at Tyr-397 and Tyr-925, c-Src at Tyr-416, recruitment of the adapter proteins p130(Cas), Shc, and Nck, and activation of the extracellular-regulated kinases ERK1/2. A synthetic peptide containing the Arg-Gly-Asp (RGD) motif of fibronectin and vitronectin was used to stimulate adult feline cardiomyocytes cultured on laminin or within a type-I collagen matrix. Whereas cardiocytes under both conditions showed RGD-stimulated ERK1/2 activation, only collagen-embedded cells exhibited cytoskeletal assembly of FAK, c-Src, Nck, and Shc. In RGD-stimulated collagen-embedded cells, FAK was phosphorylated only at Tyr-397 and c-Src association occurred without Tyr-416 phosphorylation and p130(Cas) association. Therefore, c-Src activation is not required for its cytoskeletal binding but may be important for additional phosphorylation of FAK. Overall, our study suggests that multiple signaling pathways originate in pressure-overloaded heart following integrin engagement with ECM proteins, including focal complex formation and ERK1/2 activation, and many of these pathways can be activated in cardiomyocytes via RGD-stimulated integrin activation.

  18. Defining Left Ventricular Hypertrophy in Children on Peritoneal Dialysis

    PubMed Central

    Bakkaloglu, Sevcan A.; Zaritsky, Joshua; Suarez, Angela; Wong, William; Ranchin, Bruno; Qi, Cao; Szabo, Attila J.; Coccia, Paula A.; Harambat, Jérôme; Mitu, Florin; Warady, Bradley A.; Schaefer, Franz

    2011-01-01

    Summary Background and objectives Left ventricular hypertrophy (LVH) is an important end point of dialysis-associated cardiovascular disease. The objective of this study was to evaluate the effect of different pediatric reference systems on the estimated prevalence of LVH in children on chronic peritoneal dialysis (CPD). Design, setting, participants, & measurements Echocardiographic studies in 507 pediatric CPD patients from neonatal age to 19 years were collected in 55 pediatric dialysis units around the globe. We compared the prevalence of LVH on the basis of the traditional cutoff of left ventricular mass (LVM) index (>38.5 g/m2.7) with three novel definitions of LVH that were recently established in healthy pediatric cohorts. Results Application of the new reference systems eliminated the apparently increased prevalence of LVH in young children obtained by the traditional fixed LVM index cutoff currently still recommended by consensus guidelines. However, substantial differences of LVM distribution between the new reference charts resulted in a marked discrepancy in estimated LVH prevalence ranging between 27.4% and 51.7%. Conclusions Although our understanding of the anthropometric determinants of heart size during childhood is improving, more consistent normative echocardiographic data from large populations of healthy children are required for cardiovascular diagnostics and research. PMID:21737857

  19. Isolated rat hepatocytes acquire iron from lactoferrin by endocytosis.

    PubMed

    McAbee, D D

    1995-10-15

    The iron-binding protein lactoferrin (Lf) present in blood is metabolized by the liver. Isolated rat hepatocytes vigorously endocytose bovine Lf via recycling Ca2(+)-dependent binding sites, but the uptake of iron from Lf by hepatocytes has not been examined. In this study, isolated rat hepatocytes were incubated with radiolabelled bovine Lf (125I-Lf, 59Fe-Lf or 125I-59Fe-Lf) at 37 degrees C, then washed at 4 degrees C in the presence of dextran sulphate with either Ca2+ or EGTA to distinguish between total bound and internal radioactivity respectively. Cells internalized 125I-Lf protein and Lf-bound 59Fe at maximal endocytic rates of 1700 and 480 mol.cell-1.s-1 respectively. When Lf was normalized for 59Fe content, these endocytic rates were equivalent and reflected an uptake potential of at least 3400 mol of iron.cell-1.s-1. Cells prebound with 125I-59Fe-Lf to Ca2+(-)dependent sites at 4 degrees C internalized more than 80% of both 125I-Lf protein and Lf-bound 59Fe approx. 6 min after warming to 37 degrees C at similar rates (125I-Lf: k(in) = 0.276 min-1, 59Fe: k(in) = 0.303 min-1). Within 4 h at 37 degrees C, cells had released 25% or less internalized Lf protein in the form of acid-soluble 125I-by-products but retained all the Lf-delivered 59Fe. Hyperosmotic disruption of clathrin-dependent endocytosis blocked the uptake of 125I-Lf and Lf-bound 59Fe. Incubation of cells with 125I-59Fe-Lf and a 100 molar excess of diferric transferrin reduced slightly the endocytosis of 125I-Lf protein and 59Fe accumulation. Treatment of cells with the ferric chelator desferrioxamine did not alter uptake of 125I-Lf protein or Lf-bound 59Fe, but the ferrous chelator bathophenanthroline disulphonate slightly elevated endocytosis of 125I-Lf protein and Lf-bound 59Fe. These findings indicate that Lf does not release its bound iron before endocytosis. It was concluded from this study that hepatocytes take up iron from Lf at high rates by a process that requires endocytosis of Lf

  20. The effect of cysteine oxidation on isolated hepatocytes.

    PubMed Central

    Viña, J; Saez, G T; Wiggins, D; Roberts, A F; Hems, R; Krebs, H A

    1983-01-01

    Isolated hepatocytes incubated with 4mM-cysteine lose reduced glutathione, adenine nucleotides and intracellular enzymes, thus showing extensive membrane damage. The toxic effects of cysteine are enhanced by NH4Cl. Lactate, ethanol and unsaturated fatty acids afford significant protection against cysteine-induced cytoxicity. Addition of catalase to the incubation medium also protected against cysteine toxicity, indicating that H2O2 formed during the oxidation of cysteine is involved in the toxic effects observed. Under anaerobic conditions cysteine did not cause leakage of lactate dehydrogenase from cells, confirming that rapid autoxidation is an essential condition for development of the toxic effects of cysteine. PMID:6870855

  1. A novel hydrodynamic approach of drag-reducing polymers to improve left ventricular hypertrophy and aortic remodeling in spontaneously hypertensive rats

    PubMed Central

    Zhang, Xinlu; Wang, Xu; Hu, Feng; Zhou, Boda; Chen, Hai-Bin; Zha, Daogang; Liu, Yili; Guo, Yansong; Zheng, Lemin; Xiu, Jiancheng

    2016-01-01

    Drag-reducing polymers (DRPs), when added in minute concentrations, have been shown to decrease peripheral vascular resistance. In this study, the effect of DRPs on the hypertension-induced left ventricular hypertrophy and aortic remodeling was evaluated in spontaneously hypertensive rats (SHR). Male SHR and age-matched Wistar rats were divided into four groups and received intravenous injection of normal saline (NS) or DRPs. Body weight (BW), heart rate (HR) and systolic blood pressure (SBP) were measured. Echocardiography was used to evaluate the changes in left ventricle (LV) function and global wall motion. The LV and aorta were stained by hematoxylin and eosin. Cell size of cardiomyocytes and aortic medial thickness were evaluated for each section. The expression of endothelin-1 (ET-1) of LV and aorta was examined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry. There was no significant difference in the increase of SBP among SHR + NS, SHR + 10DRP and SHR + 20DRP groups. SHR + NS group had markedly smaller left ventricular end-systolic diameter and left ventricular end-diastolic diameter but bigger anterior and posterior systolic wall thicknesses, while there was no significant difference in fractional shortening and ejection fraction. The cross-sectional areas (CSAs) of cardiomyocytes and the medial thickness of the aorta in SHR + 10 (ppm) DRP and SHR + 20 (ppm) DRP groups were significantly reduced compared with SHR + NS group. The expression of ET-1 in SHR + 10DRP and SHR + 20DRP groups was significantly attenuated. These results suggest that chronic treatment with DRPs can protect against left ventricular hypertrophy and aortic remodeling. DRPs may offer a new approach to the treatment of left ventricular hypertrophy and aortic remodeling caused by hypertension. PMID:28008249

  2. A novel hydrodynamic approach of drag-reducing polymers to improve left ventricular hypertrophy and aortic remodeling in spontaneously hypertensive rats.

    PubMed

    Zhang, Xinlu; Wang, Xu; Hu, Feng; Zhou, Boda; Chen, Hai-Bin; Zha, Daogang; Liu, Yili; Guo, Yansong; Zheng, Lemin; Xiu, Jiancheng

    Drag-reducing polymers (DRPs), when added in minute concentrations, have been shown to decrease peripheral vascular resistance. In this study, the effect of DRPs on the hypertension-induced left ventricular hypertrophy and aortic remodeling was evaluated in spontaneously hypertensive rats (SHR). Male SHR and age-matched Wistar rats were divided into four groups and received intravenous injection of normal saline (NS) or DRPs. Body weight (BW), heart rate (HR) and systolic blood pressure (SBP) were measured. Echocardiography was used to evaluate the changes in left ventricle (LV) function and global wall motion. The LV and aorta were stained by hematoxylin and eosin. Cell size of cardiomyocytes and aortic medial thickness were evaluated for each section. The expression of endothelin-1 (ET-1) of LV and aorta was examined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry. There was no significant difference in the increase of SBP among SHR + NS, SHR + 10DRP and SHR + 20DRP groups. SHR + NS group had markedly smaller left ventricular end-systolic diameter and left ventricular end-diastolic diameter but bigger anterior and posterior systolic wall thicknesses, while there was no significant difference in fractional shortening and ejection fraction. The cross-sectional areas (CSAs) of cardiomyocytes and the medial thickness of the aorta in SHR + 10 (ppm) DRP and SHR + 20 (ppm) DRP groups were significantly reduced compared with SHR + NS group. The expression of ET-1 in SHR + 10DRP and SHR + 20DRP groups was significantly attenuated. These results suggest that chronic treatment with DRPs can protect against left ventricular hypertrophy and aortic remodeling. DRPs may offer a new approach to the treatment of left ventricular hypertrophy and aortic remodeling caused by hypertension.

  3. Perspective: reverse evolution.

    PubMed

    Teotónio, H; Rose, M R

    2001-04-01

    For some time, the reversibility of evolution was primarily discussed in terms of comparative patterns. Only recently has this problem been studied using experimental evolution over shorter evolutionary time frames. This has raised questions of definition, experimental procedure, and the hypotheses being tested. Experimental evolution has provided evidence for multiple population genetic mechanisms in reverse evolution, including pleiotropy and mutation accumulation. It has also pointed to genetic factors that might prevent reverse evolution, such as a lack of genetic variability, epistasis, and differential genotype-by-environment interactions. The main focus of this perspective is on laboratory studies and their relevance to the genetics of reverse evolution. We discuss reverse evolution experiments with Drosophila, bacterial, and viral populations. Field studies of the reverse evolution of melanism in the peppered moth are also reviewed.

  4. Reversible logic for supercomputing.

    SciTech Connect

    DeBenedictis, Erik P.

    2005-05-01

    This paper is about making reversible logic a reality for supercomputing. Reversible logic offers a way to exceed certain basic limits on the performance of computers, yet a powerful case will have to be made to justify its substantial development expense. This paper explores the limits of current, irreversible logic for supercomputers, thus forming a threshold above which reversible logic is the only solution. Problems above this threshold are discussed, with the science and mitigation of global warming being discussed in detail. To further develop the idea of using reversible logic in supercomputing, a design for a 1 Zettaflops supercomputer as required for addressing global climate warming is presented. However, to create such a design requires deviations from the mainstream of both the software for climate simulation and research directions of reversible logic. These deviations provide direction on how to make reversible logic practical.

  5. Reversible cortical blindness: posterior reversible encephalopathy syndrome.

    PubMed

    Bandyopadhyay, Sabyasachi; Mondal, Kanchan Kumar; Das, Somnath; Gupta, Anindya; Biswas, Jaya; Bhattacharyya, Subir Kumar; Biswas, Gautam

    2010-11-01

    Cortical blindness is defined as visual failure with preserved pupillary reflexes in structurally intact eyes due to bilateral lesions affecting occipital cortex. Bilateral oedema and infarction of the posterior and middle cerebral arterial territory, trauma, glioma and meningioma of the occipital cortex are the main causes of cortical blindness. Posterior reversible encephalopathy syndrome (PRES) refers to the reversible subtype of cortical blindness and is usually associated with hypertension, diabetes, immunosuppression, puerperium with or without eclampsia. Here, 3 cases of PRES with complete or partial visual recovery following treatment in 6-month follow-up are reported.

  6. Effects of methylmercury on primary cultured rat hepatocytes: Cell injury and inhibition of growth factor stimulated DNA synthesis

    SciTech Connect

    Tanno, Keiichi; Fukazawa, Toshiyuki; Tajima, Shizuko; Fujiki, Motoo )

    1992-08-01

    Many more studies deal with the toxicity of methylmercury on nervous tissue than on its toxicity to the liver. Methylmercury accumulates in the liver in higher concentrations than brain and the liver has the primary function of detoxifying methylmercury. According to recent studies, hepatocyte mitochondrial membranes are destroyed by methylmercury and DNA synthesis is inhibited by methylmercury during hepatocyte regeneration. Methylmercury alters the membrane ion permeability of isolate skate hepatocytes, and inhibits the metal-sensitive alcohol dehydrogenase and glutathione reductase of primary cultured rat hepatocytes. However, little is known about the effect of methylmercury on hepatocyte proliferation in primary cultured rat hepatocytes. We therefore used the primary cultured rat hepatocytes to investigate the effects of methylmercury on cell injury and growth factor stimulate DNA synthesis. The primary effect of methylmercury is to inhibit hepatocyte proliferation rather than to cause direct cell injury. 16 refs., 4 figs.

  7. HepatoDyn: A Dynamic Model of Hepatocyte Metabolism That Integrates 13C Isotopomer Data

    PubMed Central

    Foguet, Carles; Selivanov, Vitaly A.; Fanchon, Eric; Guinovart, Joan J.; de Atauri, Pedro; Cascante, Marta

    2016-01-01

    The liver performs many essential metabolic functions, which can be studied using computational models of hepatocytes. Here we present HepatoDyn, a highly detailed dynamic model of hepatocyte metabolism. HepatoDyn includes a large metabolic network, highly detailed kinetic laws, and is capable of dynamically simulating the redox and energy metabolism of hepatocytes. Furthermore, the model was coupled to the module for isotopic label propagation of the software package IsoDyn, allowing HepatoDyn to integrate data derived from 13C based experiments. As an example of dynamical simulations applied to hepatocytes, we studied the effects of high fructose concentrations on hepatocyte metabolism by integrating data from experiments in which rat hepatocytes were incubated with 20 mM glucose supplemented with either 3 mM or 20 mM fructose. These experiments showed that glycogen accumulation was significantly lower in hepatocytes incubated with medium supplemented with 20 mM fructose than in hepatocytes incubated with medium supplemented with 3 mM fructose. Through the integration of extracellular fluxes and 13C enrichment measurements, HepatoDyn predicted that this phenomenon can be attributed to a depletion of cytosolic ATP and phosphate induced by high fructose concentrations in the medium. PMID:27124774

  8. IGF-I mediated inhibition of leptin receptor expression in porcine hepatocytes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to elucidate hormonal control of leptin receptor gene expression in primary cultures of porcine hepatocytes. Hepatocytes were isolated from pigs (52 kg) and seeded into collagen-coated T-25 flasks. Monolayer cultures were established in medium containing fetal bovine serum fo...

  9. Lipopolysaccharide Is Cleared from the Circulation by Hepatocytes via the Low Density Lipoprotein Receptor

    PubMed Central

    Topchiy, Elena; Cirstea, Mihai; Kong, HyeJin Julia; Boyd, John H.; Wang, Yingjin; Russell, James A.; Walley, Keith R.

    2016-01-01

    Sepsis is the leading cause of death in critically ill patients. While decreased Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) function improves clinical outcomes in murine and human sepsis, the mechanisms involved have not been fully elucidated. We tested the hypothesis that lipopolysaccharide (LPS), the major Gram-negative bacteria endotoxin, is cleared from the circulation by hepatocyte Low Density Lipoprotein Receptors (LDLR)—receptors downregulated by PCSK9. We directly visualized LPS uptake and found that LPS is rapidly taken up by hepatocytes into the cell periphery. Over the course of 4 hours LPS is transported towards the cell center. We next found that clearance of injected LPS from the blood was reduced substantially in Ldlr knockout (Ldlr-/-) mice compared to wild type controls and, simultaneously, hepatic uptake of LPS was also reduced in Ldlr-/- mice. Specifically examining the role of hepatocytes, we further found that primary hepatocytes isolated from Ldlr-/- mice had greatly decreased LPS uptake. In the HepG2 immortalized human hepatocyte cell line, LDLR silencing similarly resulted in decreased LPS uptake. PCSK9 treatment reduces LDLR density on hepatocytes and, therefore, was another independent strategy to test our hypothesis. Incubation with PCSK9 reduced LPS uptake by hepatocytes. Taken together, these findings demonstrate that hepatocytes clear LPS from the circulation via the LDLR and PCSK9 regulates LPS clearance from the circulation during sepsis by downregulation of hepatic LDLR. PMID:27171436

  10. Effect of Dimethyl Sulfoxide and Melatonin on the Isolation of Human Primary Hepatocytes.

    PubMed

    Solanas, Estela; Sostres, Carlos; Serrablo, Alejandro; García-Gil, Agustín; García, Joaquín J; Aranguren, Francisco J; Jiménez, Pilar; Hughes, Robin D; Serrano, María T

    2015-01-01

    The availability of fully functional human hepatocytes is critical for progress in human hepatocyte transplantation and the development of bioartificial livers and in vitro liver systems. However, the cell isolation process impairs the hepatocyte status and determines the number of viable cells that can be obtained. This study aimed to evaluate the effects of using dimethyl sulfoxide (DMSO) and melatonin in the human hepatocyte isolation protocol. Human hepatocytes were isolated from liver pieces resected from 10 patients undergoing partial hepatectomy. Each piece was dissected into 2 equally sized pieces and randomized, in