Deferasirox at therapeutic doses is associated with dose-dependent hypercalciuria.

PubMed

Wong, Phillip; Polkinghorne, Kevan; Kerr, Peter G; Doery, James C G; Gillespie, Matthew T; Larmour, I; Fuller, Peter J; Bowden, Donald K; Milat, Frances

2016-04-01

Deferasirox is an oral iron chelator used widely in the treatment of thalassemia major and other transfusion-dependent hemoglobinopathies. Whilst initial long-term studies established the renal safety of deferasirox, there are now increasing reports of hypercalciuria and renal tubular dysfunction. In addition, urolithiasis with rapid loss of bone density in patients with β thalassemia major has been reported. We conducted a cross-sectional cohort study enrolling 152 adult patients comprising of β thalassemia major (81.5%), sickle cell disease (8%), thalassemia intermedia (2%), HbH disease (6.5%) and E/β thalassemia (2%). Cases were matched with normal control subjects on age, gender and serum creatinine. Iron chelator use was documented and urine calcium to creatinine ratios measured. At the time of analysis, 88.8% of patients were receiving deferasirox and 11.2% were on deferoxamine. Hypercalciuria was present in 91.9% of subjects on deferasirox in a positive dose-dependent relationship. This was not seen with subjects receiving deferoxamine. At a mean dose of 30.2±8.8mg/kg/day, deferasirox was associated with an almost 4 fold increase in urine calcium to creatinine ratio (UCa/Cr). Hypercalciuria was present at therapeutic doses of deferasirox in a dose-dependent manner and warrants further investigation and vigilance for osteoporosis, urolithiasis and other markers of renal dysfunction. Copyright © 2016 Elsevier Inc. All rights reserved.

Hypercalciuria in a child with acral peeling skin syndrome: a case report.

PubMed

Gorczyca, Daiva; Węgłowska, Jolanta; Prescha, Anna; Woźniak, Zdzisław; Nesteruk, Dominika; Wertheim-Tysarowska, Katarzyna; Śmigiel, Robert

2015-01-01

We present a case of 3-year-old Caucasian boy who developed monthly cyclic attacks of skin peeling of the palms and soles over 1.5 years. The skin peeling was associated with hypercalciuria. No mutation was present in TGM5 and CSTA genes, but the typical clinical picture and the biopsy from flaccid blisters on the feet confirmed the acral peeling skin syndrome (APSS). The possible associations of rare genetic disorders and metabolic conditions in the course of APSS need to be investigated.

TRPV5-mediated Ca2+ Reabsorption and Hypercalciuria

NASA Astrophysics Data System (ADS)

Renkema, Kirsten Y.; Hoenderop, Joost G. J.; Bindels, René J. M.

2007-04-01

The concerted action of the intestine, kidney and bone results in the maintenance of a normal Ca2+ balance, a mechanism that is tightly controlled by the calciotropic hormones vitamin D, parathyroid hormone and calcitonin. Disturbances in the Ca2+ balance have been linked to diverse pathophysiological disorders like urolithiasis, hypertension, electroencephalogram abnormalities and rickets. Importantly, the final amount of Ca2+ that is released from the body is determined in the distal part of the nephron, where active Ca2+ reabsorption occurs. Here, Transient Receptor Potential Vanilloid member 5 (TRPV5), a highly Ca2+-selective channel, has been recognized as the gatekeeper of active Ca2+ reabsorption. The in vivo relevance of TRPV5 has been further investigated by the characterization of TRPV5 knockout (TRPV5-/-) mice, which exhibit severe disturbances in renal Ca2+ handling, such as profound hypercalciuria, intestinal Ca2+ hyperabsorption and reduced bone thickness. Hypercalciuria increases the risk of kidney stone formation in these mice. This review highlights our current knowledge about TRPV5-mediated Ca2+ reabsorption and emphasizes the physiological relevance and the clinical implications related to the TRPV5-/- mice model.

A compound heterozygous mutation in SLC34A3 causes hereditary hypophosphatemic rickets with hypercalciuria in a Chinese patient.

PubMed

Chi, Yue; Zhao, Zhen; He, Xiaodong; Sun, Yue; Jiang, Yan; Li, Mei; Wang, Ou; Xing, Xiaoping; Sun, Andrew Y; Zhou, Xueying; Meng, Xunwu; Xia, Weibo

2014-02-01

Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is a rare metabolic disorder inherited in an autosomal recessive fashion and characterized by hypophosphatemia, short stature, rickets and/or osteomalacia, and secondary absorptive hypercalciuria. HHRH was recently mapped to chromosome 9q34, which contains the gene SLC34A3 which encodes the renal proximal tubular sodium-phosphate cotransporter NaPi-IIc. Here we describe a 29-year-old man with a history of childhood rickets who presented with increased renal phosphate clearance leading to hypophosphatemia, hypercalciuria, low serum parathyroid hormone (PTH), elevated serum 1,25-dihydroxyvitamin D (1,25(OH)2D) and recurrent nephrolithiasis. We performed a mutation analysis of SLC34A3 (exons and adjacent introns) of the proband and his parents to determine if there was a genetic contribution. The proband proved to be compound heterozygous for two missense mutations in SLC34A3: one novel mutation in exon 7 c.571G>C (p.G191R) and one previously identified mutation in exon 13 c.1402C>T (p.R468W). His parents were both asymptomatic heterozygous carriers of one of these two mutations. We also performed an oral phosphate loading test and compared serum phosphate, intact PTH, and intact fibroblast growth factor 23 (iFGF23) in this patient versus patients with other forms of hypophosphatemic rickets, the results of which further revealed that the mechanism of hypophosphatemia in HHRH is independent of FGF23. This is the first report of HHRH in the Chinese population. Our findings of the novel mutation in exon 7 add to the list of more than 20 reported mutations of SLC34A3. Copyright © 2013 Elsevier Inc. All rights reserved.

Hypophosphatemic Rickets with Hypercalciuria due to Mutation in SLC34A3/NaPi-IIc can be Masked by Vitamin D Deficiency and can be Associated with Renal Calcifications

PubMed Central

Kremke, B.; Bergwitz, C.; Ahrens, W.; Schütt, S.; Schumacher, M.; Wagner, V.; Holterhus, P.-M.; Jüppner, H.; Hiort, O.

2015-01-01

Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is caused by mutations in SLC34A3, the gene encoding the renal sodium-phosphate co-transporter NaPi-IIc. Despite increased urinary calcium excretion, HHRH is typically not associated with kidney stones prior to treatment. However, here we describe two sisters, who displayed nephrolithiasis or nephrocalcinosis upon presentation. The index patient, II-4, presented with short stature, bone pain, and knee X-rays suggestive of mild rickets at age 8.5 years. Laboratory evaluation showed hypophosphatemia, elevated 1,25(OH) 2 vitamin D levels, and hypercalciuria, later also developing vitamin D deficiency. Her sister, II-6, had a low normal serum phosphorous level, biochemically vitamin D deficiency and no evidence for osteomalacia, but had undergone left nephro-ureterectomy at age 17 because of ureteral stricture secondary to renal calculi. Nucleotide sequence analysis of DNA from II-4 and II-6 revealed a homozygous missense mutation c.586G>A (p.G196R) in SLC34A3/NaPi-IIc. Ultrasonographic examinations prior to treatment showed grade I nephrocalcinosis for II-4, while II-6 had grade I-II nephrocalcinosis in her remaining kidney. Four siblings and the mother were heterozygous carriers of the mutation, but showed no biochemical abnormalities. With oral phosphate supplements, hypophosphatemia and hypercalciuria improved in both homozygous individuals. Renal calcifications that are presumably due to increased urinary calcium excretion can be the presenting finding in homozygous carriers of G196R in SLC34A3/NaPi-IIc, and some or all laboratory features of HHRH may be masked by vitamin D deficiency. PMID:18523928

Hypophosphatemic rickets with hypercalciuria due to mutation in SLC34A3/NaPi-IIc can be masked by vitamin D deficiency and can be associated with renal calcifications.

PubMed

Kremke, B; Bergwitz, C; Ahrens, W; Schütt, S; Schumacher, M; Wagner, V; Holterhus, P-M; Jüppner, H; Hiort, O

2009-02-01

Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is caused by mutations in SLC34A3, the gene encoding the renal sodium-phosphate co-transporter NaPi-IIc. Despite increased urinary calcium excretion, HHRH is typically not associated with kidney stones prior to treatment. However, here we describe two sisters, who displayed nephrolithiasis or nephrocalcinosis upon presentation. The index patient, II-4, presented with short stature, bone pain, and knee X-rays suggestive of mild rickets at age 8.5 years. Laboratory evaluation showed hypophosphatemia, elevated 1,25(OH) (2) vitamin D levels, and hypercalciuria, later also developing vitamin D deficiency. Her sister, II-6, had a low normal serum phosphorous level, biochemically vitamin D deficiency and no evidence for osteomalacia, but had undergone left nephro-ureterectomy at age 17 because of ureteral stricture secondary to renal calculi. Nucleotide sequence analysis of DNA from II-4 and II-6 revealed a homozygous missense mutation c.586G>A (p.G196R) in SLC34A3/NaPi-IIc. Ultrasonographic examinations prior to treatment showed grade I nephrocalcinosis for II-4, while II-6 had grade I-II nephrocalcinosis in her remaining kidney. Four siblings and the mother were heterozygous carriers of the mutation, but showed no biochemical abnormalities. With oral phosphate supplements, hypophosphatemia and hypercalciuria improved in both homozygous individuals. Renal calcifications that are presumably due to increased urinary calcium excretion can be the presenting finding in homozygous carriers of G196R in SLC34A3/NaPi-IIc, and some or all laboratory features of HHRH may be masked by vitamin D deficiency.

Late-onset hereditary hypophosphatemic rickets with hypercalciuria (HHRH) due to mutation of SLC34A3/NPT2c.

PubMed

Dhir, Gauri; Li, Dong; Hakonarson, Hakon; Levine, Michael A

2017-04-01

To identify a genetic basis for markedly reduced bone density and multiple fractures in an adult patient with hypophosphatemia and hypercalciuria. A 54-year-old Vietnamese man, his unaffected two daughters and wife. We performed biochemical studies and sequenced the SLC34A3 gene using genomic DNA from peripheral blood mononuclear cells. Biochemical evaluation of the proband revealed hypophosphatemia with increased renal phosphate wasting, hypercalciuria, low serum parathyroid hormone (PTH) and an elevated serum 1,25(OH) 2 D level. Mutation analysis of SLC34A3 gene revealed that the patient was a compound heterozygote for two nonsynonymous nucleotide substitutions: a novel c.571G>A (p.G191S) damaging mutation and the previously reported c.200G>A (p.R67H) polymorphism, consistent with the clinical diagnosis of late-onset hereditary hypophosphatemic rickets with hypercalciuria (HHRH). His wife and older daughter both carried the p.R67H polymorphism, while his younger daughter was compound heterozygous for p.R67H and p.G191S. HHRH is an uncommon autosomal recessive disease that generally manifests in childhood as rickets or nephrolithiasis, but an adult onset phenotype may occur in heterozygous carriers of SLC34A3 mutations. The severe presentation of this proband in adulthood with marked nephrolithiasis, multiple fractures and low bone density emphasizes the importance of measuring the serum phosphorus level in patients with suspected but unexplained osteoporosis and/or recurrent renal stones. The recognition of late-onset HHRH facilitates timely institution of appropriate therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

Prevalence and spot urine risk factors for renal stones in children taking topiramate.

PubMed

Corbin Bush, Nicol; Twombley, Katherine; Ahn, Justin; Oliveira, Carlos; Arnold, Susan; Maalouf, Naim M; Sakhaee, Khashayar

2013-12-01

Topiramate (TPM), an anti-epileptic drug with >4 million users, increases renal stones in adults. We screened outpatient TPM-treated children without history of stones to estimate the prevalence of renal stones and to characterize urine stone-risk profiles. Children taking TPM ≥1 month underwent an interview, renal ultrasound, and spot urine testing in this prospective study. Normal spot urine values were defined as: calcium/creatinine ratio ≤0.20 mg/mg (>12 months) or ≤0.60 mg/mg (≤12 months), citrate/creatinine ratio >0.50 mg/mg, and pH ≤ 6.7. Of 41 patients with average age of 9.2 years (range 0.5-18.7), mean TPM dose of 8.0 mg/kg/day (range 1.4-23.6), and mean treatment duration of 27 months (range 1-112), two (4.9%) had renal stones. The majority of children taking TPM had lithogenic abnormalities on spot urine testing, including 21 (51%) with hypercalciuria, 38 (93%) with hypocitraturia, and 28 (68%) with pH ≥ 6.7. Hypercalciuria and hypocitraturia were independent of TPM dose and duration; urine pH increased with dose. 24-h urine parameters improved in 1 stone-former once TPM was weaned. Asymptomatic stones were found in 2/41 (4.8%) children taking TPM. Risk factors for stones were present in the spot urine of most children, including hypocitraturia (93%) and hypercalciuria (51%), independent of TPM dose and duration. High urine pH, found in 68%, correlated with TPM dose. Pediatric specialists should be aware of increased risks for stones, hypercalciuria, hypocitraturia, and alkaline urine in children taking TPM. Published by Elsevier Ltd.

Vitamin D, Hypercalciuria and Kidney Stones

PubMed Central

Letavernier, Emmanuel; Daudon, Michel

2018-01-01

The estimated lifetime risk of nephrolithiasis is growing nowadays, and the formation of kidney stones is frequently promoted by hypercalciuria. Vitamin D, and especially its active metabolite calcitriol, increase digestive calcium absorption—as urinary calcium excretion is directly correlated with digestive calcium absorption, vitamin D metabolites could theoretically increase calciuria and promote urinary stone formation. Nevertheless, there was, until recently, low evidence that 25-hydroxyvitamin D serum levels would be correlated with kidney stone formation, even if high calcitriol concentrations are frequently observed in hypercalciuric stone formers. Low 25-hydroxyvitamin D serum levels have been associated with a broad spectrum of diseases, leading to a huge increase in vitamin D prescription in the general population. In parallel, an increased frequency of kidney stone episodes has been observed in prospective studies evaluating vitamin D alone or in association with calcium supplements, and epidemiological studies have identified an association between high 25-hydroxyvitamin D serum levels and kidney stone formation in some groups of patients. Moreover, urinary calcium excretion has been shown to increase in response to vitamin D supplements, at least in some groups of kidney stone formers. It seems likely that predisposed individuals may develop hypercalciuria and kidney stones in response to vitamin D supplements. PMID:29562593

Familial microscopic hematuria caused by hypercalciuria and hyperuricosuria.

PubMed

Praga, M; Alegre, R; Hernández, E; Morales, E; Domínguez-Gil, B; Carreño, A; Andrés, A

2000-01-01

We report 12 patients belonging to five different families in whom persistent isolated microhematuria was associated with hypercalciuria and/or hyperuricosuria. Four patients had episodes of gross hematuria, three patients had passed renal stones, and a history of nephrolithiasis was obtained in four of the families (80%). Calcium oxalate and uric acid crystals were commonly observed in the urine sediments. Urinary erythrocytes had a normal appearance on phase-microscopic examination. Reduction of calciuria and uricosuria by thiazide diuretics, allopurinol, forced fluid intake, and dietetic measures led to a persistent normalization of urine sediment with complete disappearance of hematuria. Determination of calcium and uric acid urinary excretions should be included in the study of familial hematuria.

Urine risk factors in children with calcium kidney stones and their siblings

PubMed Central

Bergsland, Kristin J.; Coe, Fredric L.; White, Mark D.; Erhard, Michael J.; DeFoor, William R.; Mahan, John D.; Schwaderer, Andrew L.; Asplin, John R.

2012-01-01

Calcium nephrolithiasis in children is increasing in prevalence and tends to be recurrent. Although children have a lower incidence of nephrolithiasis than adults, its etiology in children is less well understood; hence treatments targeted for adults may not be optimal in children. To better understand metabolic abnormalities in stone forming children, we compared chemical measurements and the crystallization properties of 24-hour urine collections from 129 stone formers matched to 105 non-stone forming siblings and 183 normal, healthy children with no family history of stones; all aged 6 to 17 years. The principal risk factor for calcium stone formation was hypercalciuria. Stone formers have strikingly higher calcium excretion along with high supersaturation for calcium oxalate and calcium phosphate, and a reduced distance between the upper limit of metastability and supersaturation for calcium phosphate, indicating increased risk of calcium phosphate crystallization. Other differences in urine chemistry that exist between adult stone formers and normal individuals such as hyperoxaluria, hypocitraturia, abnormal urine pH and low urine volume were not found in these children. Hence, hypercalciuria and a reduction in the gap between calcium phosphate upper limit of metastability and supersaturation are crucial determinants of stone risk. This highlights the importance of managing hypercalciuria in children with calcium stones. PMID:22358148

Urine risk factors in children with calcium kidney stones and their siblings.

PubMed

Bergsland, Kristin J; Coe, Fredric L; White, Mark D; Erhard, Michael J; DeFoor, William R; Mahan, John D; Schwaderer, Andrew L; Asplin, John R

2012-06-01

Calcium nephrolithiasis in children is increasing in prevalence and tends to be recurrent. Although children have a lower incidence of nephrolithiasis than adults, its etiology in children is less well understood; hence, treatments targeted for adults may not be optimal in children. To better understand metabolic abnormalities in stone-forming children, we compared chemical measurements and the crystallization properties of 24-h urine collections from 129 stone formers matched to 105 non-stone-forming siblings and 183 normal, healthy children with no family history of stones, all aged 6 to 17 years. The principal risk factor for calcium stone formation was hypercalciuria. Stone formers have strikingly higher calcium excretion along with high supersaturation for calcium oxalate and calcium phosphate, and a reduced distance between the upper limit of metastability and supersaturation for calcium phosphate, indicating increased risk of calcium phosphate crystallization. Other differences in urine chemistry that exist between adult stone formers and normal individuals such as hyperoxaluria, hypocitraturia, abnormal urine pH, and low urine volume were not found in these children. Hence, hypercalciuria and a reduction in the gap between calcium phosphate upper limit of metastability and supersaturation are crucial determinants of stone risk. This highlights the importance of managing hypercalciuria in children with calcium stones.

Idiopathic hypercalciuria with bilateral macular colobomata: a new variant of oculo-renal syndrome.

PubMed

Meier, W; Blumberg, A; Imahorn, W; De Luca, F; Wildberger, H; Oetliker, O

1979-01-01

Two siblings from a consanguineous family, suffering from nephrocalcinosis and nephrolithiasis caused by idiopathic hypercalciuria are described. The condition is associated with bilateral macular colobomata and tapeto-retinal degeneration. It is known that the latter can occur together with different nephropathies; however, until now it has never been described in combination with idiopathic hypercalciuria. Blood calcium levels were found to be normal, calcium excretion rates were, with one exception, more than 6 mg/kg/24 h corrected for 100 ml GFR. Hypomagnesemia of 1.5 and 1.2 mg/dl and hyermagnesuria of 1.9 and 2.5 mg/kg/24 h corrected for 100 ml GFR were found in both patients. Tubular phosphate reabsorption reached 87% and 84% at serum parathormone levels of 0.34 microgram/l and 0.31 microgram/l in the two patients, respectively. Under calcium and magnesium loading the clearance rates of calcium and magnesium were raised whilst there was only a small insignificant increase in the blood levels of these cations. Acid-base titrations showed normal excretion rates of acid and base in one patient and a mild proximal tubular acidosis in the other. Quantitative investigation of the renal concentrating and diluting capacity established a decrease in the formation of the medullary concentrating gradient in both patients.

Calcilytic Ameliorates Abnormalities of Mutant Calcium-Sensing Receptor (CaSR) Knock-In Mice Mimicking Autosomal Dominant Hypocalcemia (ADH).

PubMed

Dong, Bingzi; Endo, Itsuro; Ohnishi, Yukiyo; Kondo, Takeshi; Hasegawa, Tomoka; Amizuka, Norio; Kiyonari, Hiroshi; Shioi, Go; Abe, Masahiro; Fukumoto, Seiji; Matsumoto, Toshio

2015-11-01

Activating mutations of calcium-sensing receptor (CaSR) cause autosomal dominant hypocalcemia (ADH). ADH patients develop hypocalcemia, hyperphosphatemia, and hypercalciuria, similar to the clinical features of hypoparathyroidism. The current treatment of ADH is similar to the other forms of hypoparathyroidism, using active vitamin D3 or parathyroid hormone (PTH). However, these treatments aggravate hypercalciuria and renal calcification. Thus, new therapeutic strategies for ADH are needed. Calcilytics are allosteric antagonists of CaSR, and may be effective for the treatment of ADH caused by activating mutations of CaSR. In order to examine the effect of calcilytic JTT-305/MK-5442 on CaSR harboring activating mutations in the extracellular and transmembrane domains in vitro, we first transfected a mutated CaSR gene into HEK cells. JTT-305/MK-5442 suppressed the hypersensitivity to extracellular Ca(2+) of HEK cells transfected with the CaSR gene with activating mutations in the extracellular and transmembrane domains. We then selected two activating mutations locating in the extracellular (C129S) and transmembrane (A843E) domains, and generated two strains of CaSR knock-in mice to build an ADH mouse model. Both mutant mice mimicked almost all the clinical features of human ADH. JTT-305/MK-5442 treatment in vivo increased urinary cAMP excretion, improved serum and urinary calcium and phosphate levels by stimulating endogenous PTH secretion, and prevented renal calcification. In contrast, PTH(1-34) treatment normalized serum calcium and phosphate but could not reduce hypercalciuria or renal calcification. CaSR knock-in mice exhibited low bone turnover due to the deficiency of PTH, and JTT-305/MK-5442 as well as PTH(1-34) increased bone turnover and bone mineral density (BMD) in these mice. These results demonstrate that calcilytics can reverse almost all the phenotypes of ADH including hypercalciuria and renal calcification, and suggest that calcilytics can become a novel therapeutic agent for ADH. © 2015 American Society for Bone and Mineral Research.

Hypoparathyroidism

MedlinePlus

... and slow mental development. Too much treatment with vitamin D and calcium can cause high blood calcium ( hypercalcemia ) or high urine calcium (hypercalciuria). Excess treatment may sometimes interfere with kidney function, or ...

Kidney function and influence of sunlight exposure in patients with impaired 24-hydroxylation of vitamin D due to CYP24A1 mutations.

PubMed

Figueres, Marie-Lucile; Linglart, Agnès; Bienaime, Frank; Allain-Launay, Emma; Roussey-Kessler, Gwenaelle; Ryckewaert, Amélie; Kottler, Marie-Laure; Hourmant, Maryvonne

2015-01-01

Loss-of-function mutations of CYP24A1, the enzyme that converts the major circulating and active forms of vitamin D to inactive metabolites, recently have been implicated in idiopathic infantile hypercalcemia. Patients with biallelic mutations in CYP24A1 present with severe hypercalcemia and nephrocalcinosis in infancy or hypercalciuria, kidney stones, and nephrocalcinosis in adulthood. We describe a cohort of 7 patients (2 adults, 5 children) presenting with severe hypercalcemia who had homozygous or compound heterozygous mutations in CYP24A1. Acute episodes of hypercalcemia in infancy were the first symptom in 6 of 7 patients; in all patients, symptoms included nephrocalcinosis, hypercalciuria, low parathyroid hormone (PTH) levels, and higher than expected 1,25-dihydroxyvitamin D levels. Longitudinal data suggested that in most patients, periods of increased sunlight exposure tended to correlate with decreases in PTH levels and increases in calcemia and calciuria. Follow-up of the 2 adult patients showed reduced glomerular filtration rate and extrarenal manifestations, including calcic corneal deposits and osteoporosis. Cases of severe PTH-independent hypercalcemia associated with hypercalciuria in infants should prompt genetic analysis of CYP24A1. These patients should be monitored carefully throughout life because they may be at increased risk for developing chronic kidney disease. Copyright © 2014 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Aromatase Deficient Female Mice Demonstrate Altered Expression of Molecules Critical for Renal Calcium Reabsorption

NASA Astrophysics Data System (ADS)

Öz, Orhan K.; Hajibeigi, Asghar; Cummins, Carolyn; van Abel, Monique; Bindels, René J.; Kuro-o, Makoto; Pak, Charles Y. C.; Zerwekh, Joseph E.

2007-04-01

The incidence of kidney stones increases in women after the menopause, suggesting a role for estrogen deficiency. In order to determine if estrogen may be exerting an effect on renal calcium reabsorption, we measured urinary calcium excretion in the aromatase-deficient female mouse (ArKO) before and following estrogen therapy. ArKO mice had hypercalciuria that corrected during estrogen administration. To evaluate the mechanism by which estrogen deficiency leads to hypercalciuria, we examined the expression of several proteins involved in distal tubule renal calcium reabsorption, both at the message and protein levels. Messenger RNA levels of TRPV5, TRPV6, calbindin-D28K, the Na+/Ca++ exchanger (NCX1), and the plasma membrane calcium ATPase (PMCA1b) were significantly decreased in kidneys of ArKO mice. On the other hand, klotho mRNA levels were elevated in kidneys of ArKO mice. ArKO renal protein extracts had lower levels of calbindin-D28K but higher levels of the klotho protein. Immunochemistry demonstrated increased klotho expression in ArKO kidneys. Estradiol therapy normalized the expression of TRPV5, calbindin-D28K, PMCA1b and klotho. Taken together, these results demonstrate that estrogen deficiency produced by aromatase inactivation is sufficient to produce a renal leak of calcium and consequent hypercalciuria. This may represent one mechanism leading to the increased incidence of kidney stones following the menopause in women.

Effect of indapamide on urinary calcium excretion in patients with and without urinary stone disease.

PubMed

Ceylan, Kadir; Topal, Cevat; Erkoc, Reha; Sayarlioglu, Hayriye; Can, Saban; Yilmaz, Yuksel; Dogan, Ekrem; Algun, Ekrem; Gonulalan, Hasan

2005-06-01

Indapamide is an antihypertensive agent similar to thiazides, but with some different effects. Thiazide and thiazide-like diuretics are useful in preventing recurrent urinary stone formation due to their hypocalciuric effects. To determine the hypocalciuric and other effects on certain laboratory parameters of indapamide 1.5 mg in different patient groups. Four groups of patients recruited from urology and nephrology outpatient departments were experiencing non-hypercalciuric urinary stone disease (group 1), idiopathic hypercalciuria (group 2), urinary stone disease with hypercalciuria (group 3), and essential hypertension (group 4). In all patients, fasting serum uric acid, calcium, sodium, potassium, cholesterol, triglyceride, parathyroid hormone (PTH) values, and morning second-spot urine calcium and creatinine levels were assessed before and 8 weeks after treatment with indapamide. Urinary calcium excretion was reduced significantly in all groups: group 1 from 0.10 +/- 0.02 to 0.07 +/- 0.03 (mean +/-SD; 30% reduction; p < 0.001), group 2 from 0.30 +/- 0.15 to 0.15 +/- 0.10 (50% reduction; p < 0.001), group 3 from 0.35 +/- 0.15 to 0.20 +/- 0.10 (43% reduction; p < 0.001), and group 4 from 0.10 +/- 0.03 to 0.08 +/- 0.02 (20% reduction; p < 0.0010). These results should be interpreted with caution since no control group was included in this study. Mean serum uric acid and triglyceride levels were significantly increased, and mean PTH and potassium levels and diastolic and systolic blood pressure were significantly decreased in all groups. Few temporary adverse effects, such as dizziness and fatigue, were noticed and none of them caused discontinuation of treatment. Indapamide 1.5 mg/day is effective in decreasing calciuria in patients with non-hypercalciuric urinary stone disease, idiopathic hypercalciuria, urinary stone disease with hypercalciuria, and essential hypertension. This could be achieved with few adverse effects similar to those of thiazides and indapamide 2.5 mg. Indapamide decreased the PTH levels in all groups. Long-term clinical benefits of these effects should be evaluated prospectively with further randomized studies.

[Prevalence of hypercalciuria in postmenopausal women with osteoporosis].

PubMed

Carvalho, Mauricio; Kulak, Carolina Aguiar Moreira; Borba, Victória Zegbi Cochenski

2012-02-01

To determine the prevalence of hypercalciuria (HC) in postmenopausal women with osteoporosis and its relationship with clinical data and bone mineral metabolism. Calciuria was measured in 24-hour urine samples of 127 women. BMD was measured in the lumbar spine and femur by dual-energy X-ray absorptiometry (DXA). Mean age (±SD) was 64 (±8) years. According to urinary calcium excretion, patients were divided into normo- and hypercalciuric (HC). Of the 127 patients, 19 (15%) were classified as HC. The only difference between the groups was the age of onset of menopause (46 ± 6 vs. 50 ± 3 years HC, p < 0.0005). No association was found between calciuria and age, BMI, BMD, calcium, phosphorus, PTH, and alkaline phosphatase. HC is frequent in postmenopausal women with osteoporosis, and calciuria measurement should be included in the investigation of these patients.

Enhancement of renal excretion of uric acid during long-term thiazide therapy.

PubMed

Pak, C Y; Tolentino, R; Stewart, A; Galosy, R A

1978-11-01

The effect of thiazide (hydrochlorothiazide 100 mg per day orally in two divided doses for up to 3 years) on uric acid metabolism was examined in 21 patients with renal stones suffering from renal hypercalciuria or absorptive hypercalciuria. Serum concentration of uric acid increased during thiazide therapy in every patient. In 12 of 21 patients, there was a transient or persistent rise in urinary uric acid of more than 50 mg per day during treatment. The mean urinary uric acid produced by thiazide was positively correlated with the change in the renal clearance of uric acid. Thus, an increase in urinary uric acid was often associated with a rise in uric acid clearance. The results suggest that thiazide may either increase the production of uric acid or decrease the extrarenal disposal of uric acid, in some patients.

[Dent's syndrome. Nephrology follow-up of four patients of the same family].

PubMed

Coulibaly, G; Babinet, F; Champion, G

2012-04-01

Dent's syndrome is a rare inherited tubulopathy. Factors influencing renal function in this disease are not well known. The aim of our study is to investigate the evolution of the Dent's syndrome in renal plan. The study was retrospective and conducted in 2006, concerning four brothers. The genetic defect was a mutation S244L missense in exon 6 of gene CLCN5. Various parameters were studied. Patients were 8.5 to 21-years-old at the beginning of the follow-up. Two of them had chronic renal insufficiency (CRI) which evolved, at least 7 years of moderate to terminal stage. Tubular signs were made of hypokalemia, hypercalciuria, hypophosphatemia and proteinuria mostly β2 microglobulin. Improvement of these abnormalities was obtained with symptomatic treatment which has not always been well tolerated. A case of beginner nephrocalcinosis was observed. There was size and weight delay at the beginning of patient monitoring. Dent's syndrome may be complicated by CRI. It seems to appear in the second decade of life and hypercalciuria would contribute to it. Our CRI patients had significant bone disease. The hypercalciuria and proteinuria are factors over which we try to act. Clinical trials are needed to evaluate the efficacy of treatment on the reduction of CRI or its progression by reducing these factors in patients with Dent's syndrome. Copyright © 2011 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

Intronic deletions in the SLC34A3 gene: A cautionary tale for mutation analysis of hereditary hypophosphatemic rickets with hypercalciuria

PubMed Central

Ichikawa, Shoji; Tuchman, Shamir; Padgett, Leah R.; Gray, Amie K.; Baluarte, H. Jorge; Econs, Michael J.

2013-01-01

Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is a rare metabolic disorder, characterized by hypophosphatemia, variable degrees of rickets/osteomalacia, and hypercalciuria secondary to increased serum 1,25-dihydroxyvitamin D [1,25(OH)2D] levels. HHRH is caused by mutations in the SLC34A3 gene, which encodes sodium-phosphate co-transporter type IIc. A 6 ½-year-old female presented with a history of nephrolithiasis. Her metabolic evaluation revealed increased 24- hour urine calcium excretion with high serum calcium, low intact parathyroid hormone (PTH) levels, and elevated 1,25(OH)2D level. In addition, the patient had low to low-normal serum phosphorus with high urine phosphorus. The patient had normal stature; without rachitic or boney deformities or a history of fractures. Genetic analysis of SLC34A3 revealed the patient to be a compound heterozygote for a novel single base pair deletion in exon 12 (c.1304delG) and 30-base pair deletion in intron 6 (g.1440–1469del). The single-base pair mutation causes a frameshift, which results in premature stop codon. The intronic deletion is likely caused by misalignment of the 4-basepair homologous repeats and results in the truncation of an already small intron to 63 bp, which would impair proper RNA splicing of the intron. This is the fourth unique intronic deletion identified in patients with HHRH, suggesting the frequent occurrence of sequence misalignments in SLC34A3 and the importance of screening introns in patients with HHRH. PMID:24176905

Intronic deletions in the SLC34A3 gene: a cautionary tale for mutation analysis of hereditary hypophosphatemic rickets with hypercalciuria.

PubMed

Ichikawa, Shoji; Tuchman, Shamir; Padgett, Leah R; Gray, Amie K; Baluarte, H Jorge; Econs, Michael J

2014-02-01

Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is a rare metabolic disorder, characterized by hypophosphatemia, variable degrees of rickets/osteomalacia, and hypercalciuria secondary to increased serum 1,25-dihydroxyvitamin D [1,25(OH)2D] levels. HHRH is caused by mutations in the SLC34A3 gene, which encodes sodium-phosphate co-transporter type IIc. A 6-1/2-year-old female presented with a history of nephrolithiasis. Her metabolic evaluation revealed increased 24-hour urine calcium excretion with high serum calcium, low intact parathyroid hormone (PTH), and elevated 1,25(OH)2D. In addition, the patient had low to low-normal serum phosphorus with high urine phosphorus. The patient had normal stature; without rachitic or boney deformities or a history of fractures. Genetic analysis of SLC34A3 revealed the patient to be a compound heterozygote for a novel single base pair deletion in exon 12 (c.1304delG) and 30-base pair deletion in intron 6 (g.1440-1469del). The single-base pair mutation causes a frameshift, which results in premature stop codon. The intronic deletion is likely caused by misalignment of the 4-basepair homologous repeats and results in the truncation of an already small intron to 63bp, which would impair proper RNA splicing of the intron. This is the fourth unique intronic deletion identified in patients with HHRH, suggesting the frequent occurrence of sequence misalignments in SLC34A3 and the importance of screening introns in patients with HHRH. © 2013.

Marked increase in urinary excretion of apolipoproteins in children with nephrolithiasis associated with hypercalciuria.

PubMed

Kovacevic, Larisa; Lu, Hong; Caruso, Joseph A; Govil-Dalela, Tuhina; Thomas, Ronald; Lakshmanan, Yegappan

2017-06-01

Using a proteomic approach, we aimed to identify and compare the urinary excretion of proteins involved in lipid transport and metabolism in children with kidney stones and hypercalciuria (CAL), hypocitraturia (CIT), and normal metabolic work-up (NM), and in healthy controls (HCs). Additionally, we aimed to confirm these results using ELISA, and to examine the relationship between the urinary excretion of selected proteins with demographic, dietary, blood, and urinary parameters. Prospective, controlled, pilot study of pooled urine from CAL, CIT, and NM versus age- and gender-matched HCs, using liquid chromatography-mass spectrometry. Relative protein abundance was estimated using spectral counting. Results were confirmed by ELISA performed on individual samples. Of the 1,813 proteins identified, 230 met the above criteria. Of those, 5 proteins (apolipoprotein A-II [APOA2]; apolipoprotein A-IV [APOA4]; apolipoprotein C-III [APOA3]; fatty acid-binding protein, liver [FABPL]; fatty acid-binding protein, adipocyte [FABP4]) involved in lipid metabolism and transport were found in the CAL group, with significant differences compared with HCs. ELISA analysis indicated statistically significant differences in the urinary excretion of APOC3, APOA4, and FABPL in the CAL group compared with HCs. Twenty-four-hour urinary calcium excretion correlated significantly with concentrations of ApoC3 (r = 0.77, p < 0.001), and FABPL (r = 0.80, p = 0.005). We provide proteomic data showing increased urinary excretion of lipid metabolism/transport-related proteins in children with kidney stones and hypercalciuria. These findings suggest that abnormalities in lipid metabolism might play a role in kidney stone formation.

Inappropriate phosphate excretion in idiopathic hypercalciuria: the key to a common cause and future treatment?

PubMed Central

Williams, C P; Child, D F; Hudson, P R; Soysa, L D; Davies, G K; Davies, M G; De Bolla, A R

1996-01-01

AIMS: To present experimental evidence in support of a proposed common cause for absorptive hypercalciuria, renal hypercalciuria, renal phosphate leak and enhancement of 1,25-(OH)2-vitamin D concentrations in patients presenting with renal stone disease; and to suggest further investigation with a view to new management. METHODS: An oral calcium loading test was administered to 15 patients with renal stones and 10 normal controls in the fasting state: urine and blood were collected hourly. After the second urine sample, 400 mg calcium dissolved in water was administered orally. Serum calcium, albumin, parathyroid hormone (PTH), and phosphate were measured together with urine calcium clearance and urinary phosphate from which the TmPO4/glomerular filtration rate (GFR) ratio was calculated. Serum 1,25-(OH)2-vitamin D was measured in the first serum sample. In addition, 24 hour urine calcium results were collected retrospectively from the patients' case notes over the previous 18 months. RESULTS: In the basal state, renal stone patients had an overall greater phosphaturia (lower TmPO4/GFR: median 1.72 compared with 2.10 in controls) and increased calcium clearance. Serum corrected calcium and PTH concentrations did not differ between the groups. After calcium loading, serum calcium and urine calcium clearance rose in both groups, with patients with renal stones experiencing a greater percentage fall in phosphaturia. In both groups TmPO4/GFR fell (greater phosphaturia) with increased serum corrected calcium, with the patients showing notably greater phosphaturia for any given calcium concentration. Patients also had notably greater phosphaturia compared with the serum calcium concentration for any given PTH value. Serum 1,25-(OH)2-vitamin D was higher in patients than controls and for any 1,25-(OH)2-vitamin D concentration phosphaturia measured against serum calcium was greater in patients than controls. 1,25-(OH)2-vitamin D did not correlate with phosphaturia relative to serum calcium concentrations within the patient and control groups. CONCLUSIONS: It is proposed that patients with idiopathic hypercalciuria have an "inappropriately' high phosphate excretion for any given serum calcium concentration. Loss of phosphate may induce increased activation of 1,25-(OH)2-vitamin D. Some of the commonly described causes of stone formation may be manifestations of a single mechanism. PMID:8944605

Nephrolithiasis in renal tubular acidosis.

PubMed

Buckalew, V M

1989-03-01

Renal tubular acidosis is a term applied to several conditions in which metabolic acidosis is caused by specific defects in renal tubular hydrogen ion secretion. Three types of renal tubular acidosis generally are recognized based on the nature of the tubular defect. Nephrolithiasis occurs only in type I renal tubular acidosis, a condition marked by an abnormality in the generation and maintenance of a hydrogen ion gradient by the distal tubule. A forme fruste of type I renal tubular acidosis has been described in which the characteristic defect in distal hydrogen ion secretion occurs in the absence of metabolic acidosis (incomplete renal tubular acidosis). Type I renal tubular acidosis is a heterogeneous disorder that may be hereditary, idiopathic or secondary to a variety of conditions. Secondary type I renal tubular acidosis in sporadic cases is associated most commonly with autoimmune diseases, such as Sjögren's syndrome and systemic lupus erythematosus, and it occurs more frequently in women than men. Nephrolithiasis, which may occur in any of the subsets of type I renal tubular acidosis, accounts for most of the morbidity in adults and adolescents. Major risk factors for nephrolithiasis include alkaline urine, hypercalciuria and hypocitraturia. In addition, we found hyperuricosuria in 21 per cent of the patients with type I renal tubular acidosis with nephrolithiasis. The most frequently occurring risk factor, hypocitraturia, is due to decreased filtered load and/or to increased tubular reabsorption of filtered citrate. While increased tubular reabsorption may be due to systemic acidosis, hypocitraturia occurs in incomplete renal tubular acidosis. Furthermore, alkali therapy (either bicarbonate or citrate salts) increases citrate excretion in complete and incomplete type I renal tubular acidosis. These data suggest that hypocitraturia in type I renal tubular acidosis may be due to a defect in proximal tubule function. Hypercalciuria appears to have 2 causes. It may be due to metabolic acidosis, usually in children with a hereditary defect in urine acidification. In other cases familial idiopathic hypercalciuria causes nephrocalcinosis and nephrolithiasis resulting in distal tubular damage and type I renal tubular acidosis. In these latter cases hypercalciuria is present in complete and incomplete type I renal tubular acidosis. Potassium citrate appears to reduce calcium excretion in both types of hypercalciuric type I renal tubular acidosis.(ABSTRACT TRUNCATED AT 400 WORDS)

[Role of bones in the physiopathology of idiopathic hypercalciuria: effect of amino-bisphosphonate alendronate].

PubMed

Weisinger, J R; Alonzo, E; Machado, C; Carlini, R; Martinis, R; Paz-Martínez, V; Bellorín-Font, E

1997-01-01

Previous studies from our laboratory demonstrated that bone mineral content is affected in patients with idiopathic hypercalciuria and that there is a correlation between bone mineral loss and in-vitro cytokine production. At the same time we found that short term treatment with alendronate decreased urinary calcium in these subjects. In the present study we have examined the long-term effects of alendronate treatment (10 mg/day for one year) on urinary calcium, urinary hydroxyproline and bone mineral content in 18 idiopathic hypercalciuric and 8 normocalciuric stone formers. Clinical characteristics, as well as gender and age distribution were similar in both groups. Urinary calcium and hydroxyproline, were measured monthly. Calcium excretion decreased significantly at the end of the first month, and remained lower thereafter (277 +/- 28, before vs. 202 +/- 26 mg/g creatinine, after 12 months on alendronate, p < 0.01). Urinary hydroxyproline decreased significantly during the study (125.5 +/- 32.1 vs. 39.66 +/- 17.5 mg/g creatinine, p < 0.05). Serum calcium, glomerular filtration rate, and urinary sodium, did not change during the study. Lumbar spine bone density (trabecular bone) obtained with X ray absorptiometry revealed a significant increase from 1.162 +/- 0.231 to 1.197 +/- 0.248 g/cm2 (p < 0.01). These changes were associated with a significant decrease in IL-1 alpha mRNA transcription by unstimulated and lipopolysaccharide stimulated blood mononuclear cells, as tested by the reverse transcriptase polymerase chain reaction. No changes were observed in bone cortical sites (femoral neck). Normocalciuric subjects showed no significant changes in urinary calcium. In summary, the changes observed in urinary calcium excretion and different bone metabolic parameters, suggest a role of bone in the pathophysiology of idiopathic hypercalciuria.

Novel SLC34A3 mutation causing hereditary hypophosphataemic rickets with hypercalciuria in a Gambian family.

PubMed

Braithwaite, Vickie; Pettifor, John M; Prentice, Ann

2013-03-01

Three siblings, aged 12, 4 and 2 years, presented at a Gambian clinic with bone deformities. Radiographs of knees and wrists confirmed the presence of florid rickets. The family (including 2 unaffected siblings and the mother) were investigated for hereditary rickets. The three affected siblings had biochemical features of hereditary hypophosphataemic rickets with hypercalciuria (HHRH) with normal plasma calcium and 25-hydroxyvitamin D concentrations, elevated 1,25-dihydroxyvitamin D, hypophosphataemia, hyperphosphaturia and hypercalciuria. At presentation, two of the three affected siblings had an elevated fibroblast growth factor-23 (FGF23) concentration. The mother and clinically unaffected siblings had largely normal biochemistry. Genetic analysis of the SLC34A3 gene, encoding the type IIc sodium-phosphate cotransporter, in DNA samples from the siblings and their mother was conducted. Three single nucleotide polymorphisms (SNPs) S168F, E513V and L599L were identified. E513V and L599L had been previously identified as benign polymorphisms. S168F however, is a previously unreported variant. In silico mutation evaluation predicted that the S168F mutation causes changes in the protein product which are damaging to its function. In addition, the three clinically affected siblings were homozygous in the S168F variant whereas the unaffected family members were carriers. This study describes a biochemical profile and complementary gene data consistent with a rare genetic hypophosphataemic rickets disease in a family from rural Gambia. To our knowledge, this study reports the first cases of HHRH in Africa and describes a novel causal mutation within the SLC34A3 gene. Copyright © 2012 Elsevier Inc. All rights reserved.

Bartter syndrome: presentation in an extremely premature neonate.

PubMed

Flores, F X; Ojeda, F J; Calhoun, D A

2013-08-01

Reports of Bartter syndrome in premature neonates are rare. We describe the presentation and clinical course of a neonate born at 25.6 weeks estimated gestational age with polyuria, hyponatremia, hypokalemia and hypercalciuria ,who was diagnosed with neonatal Bartter syndrome. The evaluation, diagnosis and management of neonatal Bartter syndrome in this premature neonate are discussed.

Recurrent urinary tract infections in an infant with antenatal Bartter syndrome.

PubMed

Tasic, Velibor; Pota, Liljana; Gucev, Zoran

2011-02-01

antenatal variant of Bartter syndrome is characterized by a history of polyhydramnios, premature birth, metabolic alkalosis, hypokalemia, polyuria and renal salt wasting. In this report we present a premature female baby with antenatal Barter syndrome who had three episodes of urinary tract infection (UTI), without evidence for congenital anomaly of the kidneys or urinary tract. antenatal Bartter syndrome was diagnosed according to the standard criteria. Ultrasound scan and voiding cystourethrography were performed to exclude congenital anomaly of the kidneys and urinary tract. the baby presented with early hyperkalemia and acidosis. The typical biochemical features of the Bartter syndrome were observed in the second month. Despite appropriate treatment she had persistent hypercalciuria. The clinical course was complicated with recurrent episodes of febrile UTIs. Urinary tract system imaging did not demonstrate congenital anomalies. She finally died of severe dehydration, acidosis and renal failure. since no congenital anomaly of the kidneys or urinary tract was demonstrated in our patient, we believe that severe, persistent hypercalciuria is the most important risk factor for development of recurrent UTIs.

Idiopathic hypercalciuria and formation of calcium renal stones

PubMed Central

Coe, Fredric L.; Worcester, Elaine M.; Evan, Andrew P.

2018-01-01

The most common presentation of nephrolithiasis is idiopathic calcium stones in patients without systemic disease. Most stones are primarily composed of calcium oxalate and form on a base of interstitial apatite deposits, known as Randall’s plaque. By contrast some stones are composed largely of calcium phosphate, as either hydroxyapatite or brushite (calcium monohydrogen phosphate), and are usually accompanied by deposits of calcium phosphate in the Bellini ducts. These deposits result in local tissue damage and might serve as a site of mineral overgrowth. Stone formation is driven by supersaturation of urine with calcium oxalate and brushite. The level of supersaturation is related to fluid intake as well as to the levels of urinary citrate and calcium. Risk of stone formation is increased when urine citrate excretion is <400 mg per day, and treatment with potassium citrate has been used to prevent stones. Urine calcium levels >200 mg per day also increase stone risk and often result in negative calcium balance. Reduced renal calcium reabsorption has a role in idiopathic hypercalciuria. Low sodium diets and thiazide-type diuretics lower urine calcium levels and potentially reduce the risk of stone recurrence and bone diseas PMID:27452364

Extracellular calcium antagonizes forskolin-induced aquaporin 2 trafficking in collecting duct cells.

PubMed

Procino, Giuseppe; Carmosino, Monica; Tamma, Grazia; Gouraud, Sabine; Laera, Antonia; Riccardi, Daniela; Svelto, Maria; Valenti, Giovanna

2004-12-01

Urinary concentrating defects and polyuria are the most important renal manifestations of hypercalcemia and the resulting hypercalciuria. In this study, we tested the hypothesis that hypercalciuria-associated polyuria in kidney collecting duct occurs through an impairment of the vasopressin-dependent aquaporin 2 (AQP2) water channel targeting to the apical membrane possibly involving calcium-sensing receptor (CaR) signaling. AQP2-transfected collecting duct CD8 cells were used as experimental model. Quantitation of cell surface AQP2 immunoreactivity was performed using an antibody recognizing the extracellular AQP2 C loop. Intracellular cyclic adenosine monophosphate (cAMP) accumulation was measured in CD8 cells using a cAMP enzyme immunoassay kit. To study the translocation of protein kinase C (PKC), membranes or cytosol fractions from CD8 cells were subjected to Western blotting using anti-PKC isozymes antibodies. The amount of F-actin was determined by spectrofluorometric techniques. Intracellular calcium measurements were performed by spectrofluorometric analysis with Fura-2/AM. We demonstrated that extracellular calcium (Ca2+ o) (5 mmol/L) strongly inhibited forskolin-stimulated increase in AQP2 expression in the apical plasma membrane. At least three intracellular pathways activated by extracellular calcium were found to contribute to this effect. Firstly, the increase in cAMP levels in response to forskolin stimulation was drastically reduced in cells pretreated with Ca2+ o compared to untreated cells. Second, Ca2+ o activated PKC, known to counteract vasopressin response. Third, quantification of F-actin demonstrated that Ca2+ o caused a nearly twofold increase in F-actin content compared with basal conditions. All these effects were mimicked by a nonmembrane permeable agonist of the extracellular CaR, Gd3+. Together, these data demonstrate that extracellular calcium, possibly acting through the endogenous CaR, antagonizes forskolin-induced AQP2 translocation to the apical plasma membrane in CD8 cells. In hypercalciuria, this mechanism might blunt water reabsorption and prevent further calcium concentration, thus protecting against a potential risk of urinary calcium-containing stone formation.

Nephrocalcinosis as adult presentation of Bartter syndrome type II.

PubMed

Huang, L; Luiken, G P M; van Riemsdijk, I C; Petrij, F; Zandbergen, A A M; Dees, A

2014-02-01

Bartter syndrome consists a group of rare autosomal-recessive renal tubulopathies characterised by renal salt wasting, hypokalaemic metabolic alkalosis, hypercalciuria and hyperreninaemic hyperaldosteronism. It is classified into five types. Mutations in the KCNJ1 gene (classified as type II) usually cause the neonatal form of Bartter syndrome. We describe an adult patient with a homozygous KCNJ1 mutation resulting in a remarkably mild phenotype of neonatal type Bartter syndrome.

Association of Amelogenesis Imperfecta and Bartter's Syndrome.

PubMed

Kumar, A C V; Alekya, V; Krishna, M S V V; Alekya, K; Aruna, M; Reddy, M H K; Sangeetha, B; Ram, R; Kumar, V S

2017-01-01

Bartter's syndrome is an autosomal recessive renal tubular disorder characterized by hypokalemia, hypochloremia, metabolic alkalosis, and hyperreninemia with normal blood pressure. Bartter's syndrome is associated with hypercalciuria and nephrocalcinosis. Amelogenesis imperfecta (AI) is a group of hereditary disorders that affect dental enamel. AI could be part of several syndromes. The enamel renal syndrome is the association of AI and nephrocalcinosis. We report two patients of AI with Bartter's syndrome.

Renal Calculi

PubMed Central

Yendt, E. R.

1970-01-01

The pathogenesis of renal calculi is reviewed in general terms followed by the results of investigation of 439 patients with renal calculi studied by the author at Toronto General Hospital over a 13-year period. Abnormalities of probable pathogenetic significance were encountered in 76% of patients. Idiopathic hypercalciuria was encountered in 42% of patients, primary hyperparathyroidism in 11%, urinary infection in 8% and miscellaneous disorders in 8%. The incidence of uric acid stones and cystinuria was 5% and 2% respectively. In the remaining 24% of patients in whom no definite abnormalities were encountered the mean urinary magnesium excretion was less than normal. Of 180 patients with idiopathic hypercalciuria, only 24 were females. In the diagnosis of hyperparathyroidism, the importance of detecting minimal degrees of hypercalcemia is stressed; attention is also drawn to the new observation that the upper limit of normal for serum calcium is slightly lower in females than in males. The efficacy of various measures advocated for the prevention of renal calculi is also reviewed. In the author's experience the administration of thiazides has been particularly effective in the prevention of calcium stones. Thiazides cause a sustained reduction in urinary calcium excretion and increase in urinary magnesium excretion. These agents also appear to affect the skeleton by diminishing bone resorption and slowing down bone turnover. PMID:5438766

H+, Water and Urea Transport in the Inner Medullary Collecting Duct and Their Role in the Prevention and Pathogenesis of Renal Stone Disease

NASA Astrophysics Data System (ADS)

Wall, Susan M.; Klein, Janet D.

2008-09-01

The inner medullary collecting duct (IMCD) is the final site within the kidney for the reabsorption of urea, water and electrolytes and for the secretion of H+ before the luminal fluid becomes the final urine. Transporters expressed in the IMCD contribute to the generation of the large ion gradients that exist between the interstitium and the collecting duct lumen. Thus, the luminal fluid within the human IMCD can reach an osmolality of 1200 mOsm/kg H2O and a pH of 4. This ability of the human nephron to concentrate and acidify the urine might predispose to stone formation. However, under treatment conditions that predispose to stone formation, such as during hypercalciuria, the kidney mitigates stone formation by reducing solute concentration by reducing H2O reabsorption. Moreover, the kidney attenuates stone formation by tightly controlling acid-base balance, which prevents the bone loss, hypocitraturia and hypercalciuria observed during metabolic acidosis by augmenting net H+ excretion by tightly regulating H+ transporter function and through luminal buffering, particularly with NH3. This article will review the ion transporters present in the mammalian IMCD and their role in the prevention and in the pathogenesis of renal stone formation.

Frequency of metabolic abnormalities in urinary stones patients

PubMed Central

Ahmad, Iftikhar; Pansota, Mudassar Saeed; Tariq, Muhammad; Tabassum, Shafqat Ali

2013-01-01

Objective: To determine the frequency of metabolic abnormalities in the serum and urine of patients with urinary stones disease. Methods: Two hundred patients with either multiple or recurrent urolithiasis diagnosed on ultrasonography and intravenous urography were included in this study. 24 hour urine sample were collected from each patient and sent for PH, specific gravity, Creatinine, uric acid, calcium, phosphate, oxalate, citrate and magnesium. In addition, blood sample of each patient was also sent for serum levels of urea, creatinine, uric acid, phosphate and calcium. Results: Mean age of patients was 38 ± 7.75 years with male to female ratio of 2:1. The main presenting complaint was lumber pain and 82.5% patients were found to have calcium oxalate stones on chemical analysis. Metabolic abnormalities were found in 90.5% patients, whereas there were no metabolic abnormalities in 19 (9.5%) patients. Forty patients (21.5%) only had one metabolic abnormality and 157 (78.5%) patients had multiple metabolic abnormalities. Hyperoxaluria was the most commonly observed metabolic abnormality and was found in 64.5% patients. Other significant metabolic abnormalities were hypercalciuria, Hypercalcemia, hypocitraturia and hyperuricemia. Conclusion: This study concludes that frequency of metabolic abnormalities is very high in patients with urolithiasis and hyperoxaluria, hypercalciuria and hypocitraturia are the most important metabolic abnormalities observed in these patients. PMID:24550954

Frequency of metabolic abnormalities in urinary stones patients.

PubMed

Ahmad, Iftikhar; Pansota, Mudassar Saeed; Tariq, Muhammad; Tabassum, Shafqat Ali

2013-11-01

To determine the frequency of metabolic abnormalities in the serum and urine of patients with urinary stones disease. Two hundred patients with either multiple or recurrent urolithiasis diagnosed on ultrasonography and intravenous urography were included in this study. 24 hour urine sample were collected from each patient and sent for PH, specific gravity, Creatinine, uric acid, calcium, phosphate, oxalate, citrate and magnesium. In addition, blood sample of each patient was also sent for serum levels of urea, creatinine, uric acid, phosphate and calcium. Mean age of patients was 38 ± 7.75 years with male to female ratio of 2:1. The main presenting complaint was lumber pain and 82.5% patients were found to have calcium oxalate stones on chemical analysis. Metabolic abnormalities were found in 90.5% patients, whereas there were no metabolic abnormalities in 19 (9.5%) patients. Forty patients (21.5%) only had one metabolic abnormality and 157 (78.5%) patients had multiple metabolic abnormalities. Hyperoxaluria was the most commonly observed metabolic abnormality and was found in 64.5% patients. Other significant metabolic abnormalities were hypercalciuria, Hypercalcemia, hypocitraturia and hyperuricemia. This study concludes that frequency of metabolic abnormalities is very high in patients with urolithiasis and hyperoxaluria, hypercalciuria and hypocitraturia are the most important metabolic abnormalities observed in these patients.

Research opportunities in bone demineralization, phase 3

NASA Technical Reports Server (NTRS)

Anderson, S. A. (Editor); Cohn, S. H. (Editor)

1984-01-01

An overview of bone demineralization during space flight, observations in bone demineralization and experiments related to bone loss planned for Spacelab flights, and suggestions for further research are investigated. The observations of the working group focused upon the following topics: (1) pathogenesis of bone demineralization, (2) potential for occurrence of renal stones consequent to prolonged hypercalciuria, (3) development of appropriate ground based and inflight models to study bone demineralization, (4) integration of research efforts, and (5) development of effective countermeasures.

Urolithiasis on the ketogenic diet with concurrent topiramate or zonisamide therapy

PubMed Central

Paul, Elahna; Conant, Kerry D.; Dunne, Irie E.; Pfeifer, Heidi H.; Lyczkowski, David A.; Linshaw, Michael A.; Thiele, Elizabeth A.

2011-01-01

Summary Children with refractory epilepsy who are co-treated with the ketogenic diet (KD) and carbonic anhydrase inhibitor (CA-I) anti-epileptic medications including topiramate (TPM) and zonisamide (ZNS) are at risk for urolithiasis. Retrospective chart review of all children treated with ketogenic therapy at our institution was performed in order to estimate the minimal risk of developing signs or symptoms of stone disease. Children (N = 93) were classified into groups according to KD +/− CA-I co-therapy. Fourteen patients had occult hematuria or worse, including 6 with radiologically confirmed stones. Three of 6 calculi developed in the KD + ZNS group of 17 patients who were co-treated for a cumulative total of 97 months (3.1 stones per 100 patient months). One confirmed stone was in the KD + TPM group of 22 children who were co-treated for a cumulative total of 263 months (0.4 stones per 100 patient months). All six patients had at least three of five biochemical risk factors including metabolic acidosis, concentrated urine, acid urine, hypercalciuria and hypocitraturia. Standard of care interventions to minimize hypercalciuria, crystalluria and stone formation used routinely by pediatric nephrologists should also be prescribed by neurologists treating patients with combination anti-epileptic therapy. Non-fasting KD initiation, fluid liberalization, potassium citrate prophylaxis as well as regular laboratory surveillance are indicated in this high risk population. PMID:20466520

Hypercalcemia in dogs with adenocarcinoma derived from apocrine glands of the anal sac. Biochemical and histomorphometric investigations.

PubMed

Meuten, D J; Segre, G V; Capen, C C; Kociba, G J; Voelkel, E F; Levine, L; Tashjian, A H; Chew, D J; Nagode, L A

1983-04-01

Hypercalcemia, hypercalciuria, and hyperphosphaturia were present in female dogs with adenocarcinomas derived from apocrine glands of the anal sac (CA). Remission of hypercalcemia accompanied tumor excision in all six dogs undergoing surgery, whereas tumor recurrence or growth of metastases was associated with a return of hypercalcemia. Preoperatively, the plasma concentrations of immunoreactive parathyroid hormone in all dogs were undetectable or in the low normal range. Plasma concentrations of 13,14-dihydro-15-keto-prostaglandin E2 (PGE2M) and serum 1,25-dihydroxyvitamin D were not significantly different from control dogs. Urinary cyclic AMP and hydroxyproline were increased in dogs with CA. No immunoreactive parathyroid hormone was detected in extracts from tumor tissue, and parathyroid glands from dogs with CA had ultrastructural characteristics of secretory inactivity. Lumbar vertebrae from hypercalcemic dogs had decreased trabecular bone volume and increased osteoclastic bone resorption compared with age-matched control dogs. After tumor excision, serum total calcium returned to the normal range, whereas immunoreactive parathyroid hormone increased 2- to 20-fold and 1,25-dihydroxyvitamin D decreased 2- to 8-fold. Postoperative hypocalcemia was not observed. These results indicate that CA produces a hypercalcemic factor other than immunoreactive parathyroid hormone or prostaglandin E2 that increases osteoclastic osteolysis distant from the tumor and results in hypercalcemia, hypercalciuria, and hyperphosphaturia.

Unusual case of failure to thrive: Type III Bartter syndrome.

PubMed

Agrawal, S; Subedi, K; Ray, P; Rayamajhi, A

2016-09-01

Bartter syndrome Type III is a rare autosomal recessive disorder resulting from an inherited defect in the thick ascending limb of the loop of henle of the nephrons in kidney. The typical clinical manifestations in childhood are failure to thrive and recurrent episodes of vomiting. Typical laboratory findings which help in the diagnosis are hypokalemic metabolic alkalosis, hypomagnesemia and hypercalciuria. We report a case of Type III Bartter syndrome not responding to repeated conventional treatment of failure to thrive.

Observations of a large Dent disease cohort.

PubMed

Blanchard, Anne; Curis, Emmanuel; Guyon-Roger, Tiphaine; Kahila, Diana; Treard, Cyrielle; Baudouin, Véronique; Bérard, Etienne; Champion, Gérard; Cochat, Pierre; Dubourg, Julie; de la Faille, Renaud; Devuyst, Olivier; Deschenes, Georges; Fischbach, Michel; Harambat, Jérôme; Houillier, Pascal; Karras, Alexandre; Knebelmann, Bertrand; Lavocat, Marie-Pierre; Loirat, Chantal; Merieau, Elodie; Niaudet, Patrick; Nobili, François; Novo, Robert; Salomon, Rémi; Ulinski, Tim; Jeunemaître, Xavier; Vargas-Poussou, Rosa

2016-08-01

Dent disease classically combines low-molecular-weight proteinuria, hypercalciuria with nephrocalcinosis, and renal failure. Nephrotic range proteinuria, normal calciuria, and hypokalemia have been rarely reported. It is unknown whether the changes in phenotype observed over time are explained by a decrease in glomerular filtration rate (GFR) or whether there is any phenotype-genotype relationship. To answer this we retrospectively analyzed data from 109 male patients with CLCN5 mutations (Dent-1) and 9 patients with mutation of the OCRL gene (Dent-2). In Dent-1 disease, the estimated GFR decreased with age, by 1.0 to 1.6 ml/min per 1.73 m(2)/yr in the absence and presence of nephrocalcinosis, respectively, with no significant difference. Median values of low-molecular-weight proteinuria were in the nephrotic range and remained at the same level even in late renal disease. End-stage renal disease occurred in 12 patients, at a median age of 40 years. Hypercalciuria decreased with glomerular filtration and was absent in 40% of the patients under 30 and 85% of those over the age of 30. Hypophosphatemia did not resolve with age and calcitriol concentrations were in the upper normal range. Kalemia decreased with age, with half of the patients over the age of 18 presenting with hypokalemia. Thus, no phenotype/genotype correlation was observed in this cohort of patients with Dent disease. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Effects of dietary carbohydrates on metabolism of calcium and other minerals in normal subjects and patients with noninsulin-dependent diabetes mellitus.

PubMed

Garg, A; Bonanome, A; Grundy, S M; Unger, R H; Breslau, N A; Pak, C Y

1990-04-01

Transient hypercalciuria has been noted after high carbohydrate meals which is independent of dietary calcium and is probably due to impaired renal calcium reabsorption mediated by an increase in plasma insulin levels. Based on these observations, some investigators believe that long term intake of high carbohydrate diets may increase the risk of nephrolithiasis and possibly osteoporosis. Using a randomized cross-over design, we compared high carbohydrate diets (60% carbohydrate and 25% fat) with high fat diets (50% fat and 35% carbohydrate) for effects on metabolism of calcium and other minerals in eight normal subjects and eight euglycemic patients with noninsulin-dependent diabetes mellitus. All other dietary constituents, such as protein, fiber, fluid, minerals (including Ca, Mg, Na, K, and P), and caffeine intake, were kept constant. Despite higher daylong levels of plasma insulin on the high carbohydrate diets compared to the high fat diet in both normal and noninsulin-dependent diabetic subjects, no changes in daily urinary excretion of calcium or other constituents, associated with renal stone risk, were observed. Furthermore, there was no change in fractional intestinal 47Ca absorption. Although hypercalciuria may ensue transiently after high carbohydrate meals, we conclude that substitution of simple or complex carbohydrates for fats in an isocaloric manner for a longer duration does not result in significant urinary calcium loss, and therefore, high intakes of digestible carbohydrates may not increase the risk of nephrolithiasis or osteoporosis via this mechanism.

Activation of the Ca2+-sensing receptor increases renal claudin-14 expression and urinary Ca2+ excretion

PubMed Central

Dimke, Henrik; Desai, Prajakta; Borovac, Jelena; Lau, Alyssa; Pan, Wanling; Alexander, R. Todd

2016-01-01

Kidney stones are a prevalent clinical condition imposing a large economic burden on the health-care system. Hypercalciuria remains the major risk factor for development of a Ca2+-containing stone. The kidney’s ability to alter Ca2+ excretion in response to changes in serum Ca2+ is in part mediated by the Ca2+-sensing receptor (CaSR). Recent studies revealed renal claudin-14 (Cldn14) expression localized to the thick ascending limb (TAL) and its expression to be regulated via the CaSR. We find that Cldn14 expression is increased by high dietary Ca2+ intake and by elevated serum Ca2+ levels induced by prolonged 1,25-dihydroxyvitamin D3 administration. Consistent with this, activation of the CaSR in vivo via administration of the calcimimetic cinacalcet hydrochloride led to a 40-fold increase in Cldn14 mRNA. Moreover, overexpression of Cldn14 in two separate cell culture models decreased paracellular Ca2+ flux by preferentially decreasing cation permeability, thereby increasing transepithelial resistance. These data support the existence of a mechanism whereby activation of the CaSR in the TAL increases Cldn14 expression, which in turn blocks the paracellular reabsorption of Ca2+. This molecular mechanism likely facilitates renal Ca2+ losses in response to elevated serum Ca2+. Moreover, dys-regulation of the newly described CaSR-Cldn14 axis likely contributes to the development of hypercalciuria and kidney stones. PMID:23283989

The importance of histopathology in the diagnosis of isolated renal sarcoidosis: a case report.

PubMed

Trindade Filho, João Onofre; Amaro, Kaline Daniele de Souza; Oliveira, Allana Desirée Teixeira de; Gomes, Cecília Neta Alves Pegado; Costa, Hermann Ferreira; Trajano, Vinicius Nogueira

2018-06-18

Sarcoidosis is a systemic inflammatory disease of unknown etiology, characterized by the presence of non-caseating granulomas in several organs; renal impairment alone is a rare condition. When it affects the kidneys, the most prevalent manifestations are hypercalcemia and hypercalciuria. This paper aims to address the topic of renal sarcoidosis, by means of a case report, and reinstate the importance of histopathology in its diagnosis. The data came from an observational clinical study with a qualitative approach, through an interview with the renal sarcoidosis patient and data from her medical records. Patient D.M.S., 50 years old, Caucasian, presented with reddish eyes and body pains lasting for fifteen days as first manifestations of the disease. Upon kidney ultrasound scan, we found renal parenchymal nephropathy. Serial renal function and metabolic tests reported anemia and progressive urea and creatinine changes, as well as hypercalcemia and hypercalciuria, confirming acute kidney failure (AKF). A histopathological examination suggested the diagnosis, which was confirmed by clinical, laboratory and histopathological data. There was therapeutic resolution after steroid therapy. The symptomatology of sarcoidosis is diverse and often non-specific. Renal manifestation, which usually occurs after organ involvement, is present in less than 5% of patients, and about 1% to 2% of these patients may develop AKF. The use of histopathology together with clinical and laboratory data to diagnose isolated renal sarcoidosis, rule out other etiologies and introduce early treatment is of paramount importance.

Percutaneous nephrolithotomy in an 8-week-old infant.

PubMed

Lee, Albert S; Bowen, Diana K; Vatsky, Seth; Zderic, Stephen A; Tasian, Gregory E

2018-06-01

We report successful percutaneous nephrolithotomy (PCNL) in an 8-week-old, 4.12 kg infant with a combined stone burden of > 2 cm in a solitary kidney. The patient was born with thoracolumbar myelomeningocele and had developed recurrent urinary tract infections. Her size precluded retrograde intrarenal surgery and shockwave lithotripsy would be unlikely to clear the stone burden. Stone analysis revealed hydroxyapatite and carbonate apatite stones, and metabolic work up revealed hypercalciuria for which chlorothiazide was started. To our knowledge, this is the youngest patient to undergo PCNL reported in the literature.

Extrapulmonary involvement in patients with sarcoidosis and comparison of routine laboratory and clinical data to pulmonary involvement.

PubMed

Zurkova, Monika; Kolek, Vitezslav; Tomankova, Tereza; Kriegova, Eva

2014-12-01

Patients with pulmonary and pulmonary plus extrapulmonary sarcoidosis differ in symptom severity and health status impairment. To date there is no information on differences in clinical and laboratory parameters between these phenotypes and limited information on extrapulmonary involvement in Czech sarcoidosis patients exists. We therefore compared clinical data (age, gender, organ involvement, lung function tests) and laboratory data (blood counts, bronchoalveolar fluid (BAL) cellular profile, serum levels of CRP, SACE, sIL-2R, neopterin) between patients with newly diagnosed pulmonary sarcoidosis (n=107) and those with pulmonary plus extrapulmonary sarcoidosis (n=54). Extrapulmonary sarcoidosis was diagnosed in 33% of patients, mostly affecting lymph nodes and skin and having hypercalciuria. There was no difference in the prevalence of extrapulmonary sarcoidosis between genders. Patients with extrapulmonary sarcoidosis were older and mostly non-smokers when compared to those with limited pulmonary form. X-ray Stage I and erythema nodosum were less frequent in extrapulmonary disease. Serum levels of CRP, SACE, sIL-2R and neopterin and BAL cellular profile did not differ between both phenotypes. We observed lower platelets, FEV1, VC, and BAL CD19+ in females with extrapulmonary involvement than in those with pulmonary disease. Affected lymph nodes, skin and hypercalciuria were the most common in sarcoidosis patients with extrapulmonary involvement. Pulmonary sarcoidosis did not differ in clinical and routine laboratory parameters from pulmonary plus extrapulmonary sarcoidosis. Observation of low platelets, VC, FEV1 and BAL CD19+ in females with extrapulmonary sarcoidosis needs further verification in larger cohort.

Accentuated hyperparathyroidism in type II Bartter syndrome.

PubMed

Landau, Daniel; Gurevich, Evgenia; Sinai-Treiman, Levana; Shalev, Hannah

2016-07-01

Bartter syndrome (BS) may be associated with different degrees of hypercalciuria, but marked parathyroid hormone (PTH) abnormalities have not been described. We compared clinical and laboratory data of patients with either ROMK-deficient type II BS (n = 14) or Barttin-deficient type IV BS (n = 20). Only BS-IV patients remained mildly hypokalemic in spite of a higher need for potassium supplementation. Estimated glomerular filtration rate (eGFR) was mildly decreased in only four BS-IV patients. Average PTH values were significantly higher in BS-II (160.6 ± 85.8 vs. 92.5 ± 48 pg/ml in BS-IV, p = 0.006). In both groups, there was a positive correlation between age and log(PTH). Levels of 25(OH) vitamin D were not different. Total serum calcium was lower (within normal limits) and age-related serum phosphate (Pi)-SDS was increased in BS-II (1.19 ± 0.71 vs. 0.01 ± 1.04 in BS-IV, p < 0.001). The GFR threshold for Pi reabsorption was higher in BS-II (5.63 ± 1.25 vs. 4.36 ± 0.98, p = 0.002). Spot urine calcium/creatinine ratio and nephrocalcinosis rate (100 vs. 16 %) were higher in the BS-II group. PTH, serum Pi levels, and urinary threshold for Pi reabsorption are significantly elevated in type II vs. type IV BS, suggesting a PTH resistance state. This may be a response to more severe long-standing hypercalciuria, leading to a higher rate of nephrocalcinosis in BS-II.

Renal Adaptation to Gentamicin-Induced Mineral Loss

PubMed Central

Lee, Chien-Te; Chen, Hung Chun; Ng, Hwee-Yeong; Lai, Li-Wen; Lien, Yeong-Hau H.

2012-01-01

Background Gentamicin, a well-known nephrotoxic drug, affects calcium and magnesium homeostasis. Although gentamicin induces urinary calcium and magnesium wasting immediately, it rarely causes significant hypocalcemia or hypomagnesemia clinically. Methods We conducted an animal study to investigate the renal adaptation in calcium and magnesium handling after gentamicin treatment and effects on the expression of calcium and magnesium transport molecules in distal tubule. Gentamicin (40 mg/kg) was injected daily in male Sprague-Dawley rats (220–250 g) for up to 7 days. Results This treatment did not affect serum creatinine, calcium, or magnesium levels. Gentamicin induced significant hypercalciuria (14-fold) and hypermagnesiuria (10-fold) in 6 h, which was associated with upregulation of TRPV5 (175 ± 3%), TRPV6 (170 ± 4%), TRPM6 (156 ± 4%) and calbindin-D28k (174 ± 3%; all p < 0.05 vs. control). This gene upregulation was maintained with daily injection of gentamicin for 7 days. The gentamicin-induced urinary calcium loss was reduced by 80% at days 3 and 7, while magnesium loss was reduced by 52 and 57% at days 3 and 7, respectively. On the other hand, urinary loss of potassium became worse on day 7 (2-fold), and phosphorus loss worse from day 3 to day 7 (3-fold). Conclusion There is a rapid adaptation to gentamicin-induced hypercalciuria and hypermagnesiuria. The upregulation of distal tubule transport molecules, TRPV5, TRPV6, TRPM6 and calbindin-D28k occurs within 6 h of gentamicin treatment. This renal adaptation prevents further mineral loss due to gentamicin treatment. PMID:22378246

Uncompensated polyuria in a mouse model of Bartter's syndrome

PubMed Central

Takahashi, Nobuyuki; Chernavvsky, Daniel R.; Gomez, R. Ariel; Igarashi, Peter; Gitelman, Hillel J.; Smithies, Oliver

2000-01-01

We have used homologous recombination to disrupt the mouse gene coding for the NaK2Cl cotransporter (NKCC2) expressed in kidney epithelial cells of the thick ascending limb and macula densa. This gene is one of several that when mutated causes Bartter's syndrome in humans, a syndrome characterized by severe polyuria and electrolyte imbalance. Homozygous NKCC2−/− pups were born in expected numbers and appeared normal. However, by day 1 they showed signs of extracellular volume depletion (hematocrit 51%; wild type 37%). They subsequently failed to thrive. By day 7, they were small and markedly dehydrated and exhibited renal insufficiency, high plasma potassium, metabolic acidosis, hydronephrosis of varying severity, and high plasma renin concentrations. None survived to weaning. Treatment of −/− pups with indomethacin from day 1 prevented growth retardation and 10% treated for 3 weeks survived, although as adults they exhibited severe polyuria (10 ml/day), extreme hydronephrosis, low plasma potassium, high blood pH, hypercalciuria, and proteinuria. Wild-type mice treated with furosemide, an inhibitor of NaK2Cl cotransporters, have a phenotype similar to the indomethacin-rescued −/− adults except that hydronephrosis was mild. The polyuria, hypercalciuria, and proteinuria of the −/− adults and furosemide-treated wild-type mice were unresponsive to inhibitors of the renin angiotensin system, vasopressin, and further indomethacin. Thus absence of NKCC2 in the mouse causes polyuria that is not compensated elsewhere in the nephron. The NKCC2 mutant animals should be valuable for uncovering new pathophysiologic and therapeutic aspects of genetic disturbances in water and electrolyte recovery by the kidney. PMID:10779555

Is the renal kallikrein-kinin system a factor that modulates calciuria?

PubMed

Negri, Armando Luis

Renal tubular calcium reabsorption is one of the principal factors that determine serum calcium concentration and calcium excretion. Calcium excretion is regulated by the distal convoluted tubule and connecting tubule, where the epithelial calcium channel TRPV5 can be found, which limits the rate of transcellular calcium transport. The dynamic presence of the TRPV5 channel on the surface of the tubular cell is mediated by an endosomal recycling process. Different intrarenal factors are involved in calcium channel fixation in the apical membrane, including the anti-ageing hormone klotho and tissue kallikrein (TK). Both proteins are synthesised in the distal tubule and secreted in the tubular fluid. TK stimulates active calcium reabsorption through the bradykinin receptor B2 that compromises TRPV5 activation through the protein kinase C pathway. TK-deficient mice show hypercalciuria of renal origin comparable to that seen in TRPV5 knockout mice. There is a polymorphism with loss of function of the human TK gene R53H (allele H) that causes a marked decrease in enzymatic activity. The presence of the allele H seems to be common at least in the Japanese population (24%). These individuals have a tendency to greater calcium and sodium excretion in urine that is more evident during furosemide infusion. Future studies should analyse if manipulating the renal kallikrein-kinin system can correct idiopathic hypercalciuria with drugs other than thiazide diuretics. Copyright © 2016 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

Dietary protein, calcium metabolism, and skeletal homeostasis revisited.

PubMed

Kerstetter, Jane E; O'Brien, Kimberly O; Insogna, Karl L

2003-09-01

High dietary protein intakes are known to increase urinary calcium excretion and, if maintained, will result in sustained hypercalciuria. To date, the majority of calcium balance studies in humans have not detected an effect of dietary protein on intestinal calcium absorption or serum parathyroid hormone. Therefore, it is commonly concluded that the source of the excess urinary calcium is increased bone resorption. Recent studies from our laboratory indicate that alterations in dietary protein can, in fact, profoundly affect intestinal calcium absorption. In short-term dietary trials in healthy adults, we fixed calcium intake at 20 mmol/d while dietary protein was increased from 0.7 to 2.1 g/kg. Increasing dietary protein induced hypercalciuria in 20 women [from 3.4 +/- 0.3 ( +/- SE) during the low-protein to 5.4 +/- 0.4 mmol/d during the high-protein diet]. The increased dietary protein was accompanied by a significant increase in intestinal calcium absorption from 18.4 +/- 1.3% to 26.3 +/- 1.5% (as determined by dual stable isotopic methodology). Dietary protein intakes at and below 0.8 g/kg were associated with a probable reduction in intestinal calcium absorption sufficient to cause secondary hyperparathyroidism. The long-term consequences of these low-protein diet-induced changes in mineral metabolism are not known, but the diet could be detrimental to skeletal health. Of concern are several recent epidemiologic studies that demonstrate reduced bone density and increased rates of bone loss in individuals habitually consuming low-protein diets. Studies are needed to determine whether low protein intakes directly affect rates of bone resorption, bone formation, or both.

Determinants of Brushite Stone Formation: A Case-Control Study

PubMed Central

Siener, Roswitha; Netzer, Linda; Hesse, Albrecht

2013-01-01

Purpose The occurrence of brushite stones has increased during recent years. However, the pathogenic factors driving the development of brushite stones remain unclear. Methods Twenty-eight brushite stone formers and 28 age-, sex- and BMI-matched healthy individuals were enrolled in this case-control study. Anthropometric, clinical, 24 h urinary parameters and dietary intake from 7-day weighed food records were assessed. Results Pure brushite stones were present in 46% of patients, while calcium oxalate was the major secondary stone component. Urinary pH and oxalate excretion were significantly higher, whereas urinary citrate was lower in patients as compared to healthy controls. Despite lower dietary intake, urinary calcium excretion was significantly higher in brushite stone patients. Binary logistic regression analysis revealed pH>6.50 (OR 7.296; p = 0.035), calcium>6.40 mmol/24 h (OR 25.213; p = 0.001) and citrate excretion <2.600 mmol/24 h (OR 15.352; p = 0.005) as urinary risk factors for brushite stone formation. A total of 56% of patients exhibited distal renal tubular acidosis (dRTA). Urinary pH, calcium and citrate excretion did not significantly differ between patients with or without dRTA. Conclusions Hypercalciuria, a diminished citrate excretion and an elevated pH turned out to be the major urinary determinants of brushite stone formation. Interestingly, urinary phosphate was not associated with urolithiasis. The increased urinary oxalate excretion, possibly due to decreased calcium intake, promotes the risk of mixed stone formation with calcium oxalate. Neither dietary factors nor dRTA can account as cause for hypercalciuria, higher urinary pH and diminished citrate excretion. Further research is needed to define the role of dRTA in brushite stone formation and to evaluate the hypothesis of an acquired acidification defect. PMID:24265740

Intake of dehydrated nopal (Opuntia ficus indica) improves bone mineral density and calciuria in adult Mexican women.

PubMed

Aguilera-Barreiro, María de Los Angeles; Rivera-Márquez, José Alberto; Trujillo-Arriaga, Héctor Miguel; Tamayo Y Orozco, Juan Alfredo; Barreira-Mercado, Eduardo; Rodríguez-García, Mario E

2013-01-01

The intake of dehydrated nopal (DN) at a high stage of maturity along with high calcium content could improve bone mineral density (BMD) and calciuria and thus prevent osteoporosis. To evaluate the effect of calcium intake from a vegetable source (DN) on BMD and calciuria covering a 2-year period in menopausal and non-menopausal women with low bone mass (LBM). The study was quasi-experimental, blinded, and randomized, and included 131 Mexican women aged 35-55. Urinary calcium/creatinine index (CCI) was determined; BMD was analyzed on lumbar spine and total hip regions. Four groups were studied: Control group (CG), women with normocalciuria and a minimum dose of DN; experimental group 1 (EG1), women with hypercalciuria and a minimum dose of DN; experimental group 2 (EG2), women with hypercalciuria, and a maximum dose of DN; and normal group (NG) for reference in BMD. After the first semester of treatment, calciuria levels in women from both experimental groups returned to normal, remaining constant for the rest of the treatment. The percentage difference in BMD increased in the total hip region in the CG (pre 4.5% and post 2.1%) and EG2 (pre 1.8% and post 2.5%) groups significantly in comparison to NG and EG1, which exhibited a significant decrease in their BMD. BMD increased only for the lumbar region in the EG2 group (premenopausal). The use of a vegetable calcium source such as nopal improves BMD in women with LBM in the total hip and lumbar spine regions principally in the premenopausal women, maintaining constant and normal calciuria levels.

Fasting urinary calcium-to-creatinine and oxalate-to-creatinine ratios in dogs with calcium oxalate urolithiasis and breed-matched controls.

PubMed

Furrow, E; Patterson, E E; Armstrong, P J; Osborne, C A; Lulich, J P

2015-01-01

Hypercalciuria and hyperoxaluria are risk factors for calcium oxalate (CaOx) urolithiasis, but breed-specific reports of urinary metabolites and their relationship with stone status are lacking. To compare urinary metabolites (calcium and oxalate) and blood ionized calcium (iCa) concentrations between CaOx stone formers and breed-matched stone-free controls for the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. Forty-seven Miniature Schnauzers (23 cases and 24 controls), 27 Bichons Frise (14 cases and 13 controls), and 15 Shih Tzus (7 cases and 8 controls). Prospective study. Fasting spot urinary calcium-to-creatinine and oxalate-to-creatinine ratios (UCa/Cr and UOx/Cr, respectively) and blood iCa concentrations were measured and compared between cases and controls within and across breeds. Regression models were used to test the effect of patient and environmental factors on these variables. UCa/Cr was higher in cases than controls for each of the 3 breeds. In addition to stone status, being on a therapeutic food designed to prevent CaOx stone recurrence was associated with higher UCa/Cr. UOx/Cr did not differ between cases and controls for any of the breeds. Blood iCa was higher in cases than controls in the Miniature Schnauzer and Bichon Frise breeds and had a moderate correlation with UCa/Cr. Hypercalciuria is associated with CaOx stone status in the Miniature Schnauzer, Bichon Frise, and Shih Tzu breeds. UOx/Cr did not correlate with stone status in these 3 breeds. These findings may influence breed-specific stone prevention recommendations. Copyright © 2015 by the American College of Veterinary Internal Medicine.

Intake of dehydrated nopal (Opuntia ficus indica) improves bone mineral density and calciuria in adult Mexican women

PubMed Central

Aguilera-Barreiro, María de los Angeles; Rivera-Márquez, José Alberto; Trujillo-Arriaga, Héctor Miguel; Tamayo y Orozco, Juan Alfredo; Barreira-Mercado, Eduardo; Rodríguez-García, Mario E

2013-01-01

Background The intake of dehydrated nopal (DN) at a high stage of maturity along with high calcium content could improve bone mineral density (BMD) and calciuria and thus prevent osteoporosis. Objective To evaluate the effect of calcium intake from a vegetable source (DN) on BMD and calciuria covering a 2-year period in menopausal and non-menopausal women with low bone mass (LBM). Methods The study was quasi-experimental, blinded, and randomized, and included 131 Mexican women aged 35–55. Urinary calcium/creatinine index (CCI) was determined; BMD was analyzed on lumbar spine and total hip regions. Four groups were studied: Control group (CG), women with normocalciuria and a minimum dose of DN; experimental group 1 (EG1), women with hypercalciuria and a minimum dose of DN; experimental group 2 (EG2), women with hypercalciuria, and a maximum dose of DN; and normal group (NG) for reference in BMD. Results After the first semester of treatment, calciuria levels in women from both experimental groups returned to normal, remaining constant for the rest of the treatment. The percentage difference in BMD increased in the total hip region in the CG (pre 4.5% and post 2.1%) and EG2 (pre 1.8% and post 2.5%) groups significantly in comparison to NG and EG1, which exhibited a significant decrease in their BMD. BMD increased only for the lumbar region in the EG2 group (premenopausal). Conclusion The use of a vegetable calcium source such as nopal improves BMD in women with LBM in the total hip and lumbar spine regions principally in the premenopausal women, maintaining constant and normal calciuria levels. PMID:23704856

A patient with hypophosphatemia, a femoral fracture, and recurrent kidney stones: report of a novel mutation in SLC34A3.

PubMed

Page, Kathleen; Bergwitz, Clemens; Jaureguiberry, Graciana; Harinarayan, Chittari V; Insogna, Karl

2008-10-01

To determine if there was a genetic contribution to our patient's unusual clinical presentation of nephrolithiasis and nonhealing stress fracture. We describe a 31-year-old man who had rickets as a child and developed a femur insufficiency fracture and recurrent nephrolithiasis as an adult after moving to the United States from India. The patient's clinical course and results from radiographic and biochemical analyses are described. Analysis of the SLC34A3 gene was performed using genomic DNA samples from the patient and his family members. Before referral to the Yale Bone Center, the patient was treated with calcitriol, ergocalciferol, and phosphate. Changing therapy to phosphate alone led to clinical improvement. Genetic analysis revealed that the patient is a compound heterozygote for mutations in the SLC34A3 gene. On 1 allele, he has a previously described missense mutation in exon 7: c.575C>T (p.Ser192Leu). The other allele carries a novel nonsense mutation in exon 3: c.145C>T (p.Gln49X). One unaffected sibling is a carrier of the missense mutation and 1 sister with a history of flank pain is a carrier of the novel mutation. Hereditary hypophosphatemic rickets with hypercalciuria is a rare metabolic disorder associated with mutations in SLC34A3, the gene that encodes the renal sodium phosphate cotransporter NaPi-IIc. Although hypercalciuria is a distinguishing feature of the disease, nephrolithiasis is rarely described. The patient's atypical clinical presentation illustrates that both environmental and genetic factors potentially affect phenotypic expression of SLC34A3 mutations.

Biochemical risk factors for stone formation in healthy school children.

PubMed

Akhavan-Sepahi, Mohsen; Sharifian, Mostafa; Mohkam, Maasumeh; Vafadar, Mahdi; Hejazi, Shamsaddin

2012-01-01

Prevalence of urolithiasis in childhood is increasing. The wide geographic variation in the incidence of lithiasis in childhood is related to climatic, dietary, and socioeconomic factors. Many children with stone disease have a metabolic abnormality. In Southeast Asia, urinary calculi are endemic and are related to dietary factors. The main aim of this study was to determine the prevalence of renal stone, urine metabolic abnormality, control of blood pressure and demographic character in elementary school children of Qom. A cross sectional study was performed on 110 primary school children (56 girls and 54 boys) aged 7 to 11 years old. Demographic data such as age, height, weight were gathered, and systolic and diastolic blood pressure, Urine analysis and culture, urinary levels of calcium, creatinine, phosphorus, magnesium, sodium, potassium, uric acid, cystine, citrate, oxalate, protein and sonographic findings were evaluated. The mean (±SD) of age was 8.85±1.51 years. Only one child had renal stone (1%), but the prevalence of abnormal renal sonography was 7%. The most prevalent urine metabolic abnormalities were hypercalciuria (23%) and hypocitraturia (100%). 11.2% of children had positive urine culture that all were female. The prevalence of high blood pressure was 7.1% for girls and 11.1% for boys. The prevalence of renal stone in children in this study was 1%, which means the accurate judgment about the prevalence of renal stone in Qom city needs more comprehensive studies. Similar to other studies in Iran this study shows that the prevalence of hypercalciuria is significantly higher comparing to other countries, it may be associated with excessive intake of sodium. © 2012 Tehran University of Medical Sciences. All rights reserved.

The Calcium-Sensing Receptor Increases Activity of the Renal NCC through the WNK4-SPAK Pathway.

PubMed

Bazúa-Valenti, Silvana; Rojas-Vega, Lorena; Castañeda-Bueno, María; Barrera-Chimal, Jonatan; Bautista, Rocío; Cervantes-Pérez, Luz G; Vázquez, Norma; Plata, Consuelo; Murillo-de-Ozores, Adrián R; González-Mariscal, Lorenza; Ellison, David H; Riccardi, Daniela; Bobadilla, Norma A; Gamba, Gerardo

2018-05-30

Background Hypercalciuria can result from activation of the basolateral calcium-sensing receptor (CaSR), which in the thick ascending limb of Henle's loop controls Ca 2+ excretion and NaCl reabsorption in response to extracellular Ca 2+ However, the function of CaSR in the regulation of NaCl reabsorption in the distal convoluted tubule (DCT) is unknown. We hypothesized that CaSR in this location is involved in activating the thiazide-sensitive NaCl cotransporter (NCC) to prevent NaCl loss. Methods We used a combination of in vitro and in vivo models to examine the effects of CaSR on NCC activity. Because the KLHL3-WNK4-SPAK pathway is involved in regulating NaCl reabsorption in the DCT, we assessed the involvement of this pathway as well. Results Thiazide-sensitive 22 Na + uptake assays in Xenopus laevis oocytes revealed that NCC activity increased in a WNK4-dependent manner upon activation of CaSR with Gd 3+ In HEK293 cells, treatment with the calcimimetic R-568 stimulated SPAK phosphorylation only in the presence of WNK4. The WNK4 inhibitor WNK463 also prevented this effect. Furthermore, CaSR activation in HEK293 cells led to phosphorylation of KLHL3 and WNK4 and increased WNK4 abundance and activity. Finally, acute oral administration of R-568 in mice led to the phosphorylation of NCC. Conclusions Activation of CaSR can increase NCC activity via the WNK4-SPAK pathway. It is possible that activation of CaSR by Ca 2+ in the apical membrane of the DCT increases NaCl reabsorption by NCC, with the consequent, well known decrease of Ca 2+ reabsorption, further promoting hypercalciuria. Copyright © 2018 by the American Society of Nephrology.

Effect of treatment with depot somatostatin analogue octreotide on primary hyperparathyroidism (PHP) in multiple endocrine neoplasia type 1 (MEN1) patients.

PubMed

Faggiano, Antongiulio; Tavares, Lidice Brandao; Tauchmanova, Libuse; Milone, Francesco; Mansueto, Gelsomina; Ramundo, Valeria; De Caro, Maria Laura Del Basso; Lombardi, Gaetano; De Rosa, Gaetano; Colao, Annamaria

2008-11-01

In patients with multiple endocrine neoplasia type 1 (MEN1), expression of somatostatin receptor (SST) in parathyroid adenomas and effectiveness of therapy with somatostatin analogues on primary hyperparathyroidism (PHP) have been scarcely investigated. To evaluate the effects of depot long acting octreotide (OCT-LAR) in patients with MEN1-related PHP. Eight patients with a genetically confirmed MEN1, presenting both PHP and duodeno-pancreatic neuroendocrine tumours (NET), were enrolled. The initial treatment was OCT-LAR 30 mg every 4 weeks. This therapy was established to stabilize the duodeno-pancreatic NET before to perform parathyroidectomy for PHP. Before OCT-LAR therapy, a SST scintigraphy was performed in all patients. SST subtype 2A immunohistochemistry was performed on parathyroid tumour samples from three patients undergone parathyroidectomy after OCT-LAR therapy. Serum concentrations of PTH, calcium and phosphorus as well as the 24-h urine calcium : creatinine ratio and the renal threshold phosphate concentration were evaluated before and after OCT-LAR. After OCT-LAR therapy, hypercalcaemia and hypercalciuria normalized in 75% and 62.5% of patients, respectively, and serum phosphorus and renal threshold phosphate significantly increased. Serum PTH concentrations significantly decreased in all patients and normalized in two of them. SST subtype 2A immunostaining was found in all parathyroid adenomas investigated, while SST scintigraphy showed a positive parathyroid tumour uptake in three of eight patients (37.5%). Six months of OCT-LAR therapy controlled hypercalcaemia and hypercalciuria in two-thirds of patients with MEN1-related PHP. Direct OCT-LAR effects mediated by binding to SST expression on parathyroid tumour cells are likely the main mechanism to explain the activity of this compound on calcium and phosphorus abnormalities in MEN1 PHP.

[A family history of renal lithiasis in children diagnosed of urinary tract infection by Escherichia coli].

PubMed

García Nieto, Víctor; Sotoca Fernández, Jorge; O'Hagan, Monica; Arango Sancho, Pedro; Luis Yanes, Maria Isabel

2018-04-01

Urinary tract infections (UTI) caused by Escherichia coli (E. coli) are common in patients with idiopathic hypercalciuria. As both UTI and hypercalciuria (prelithiasis) have a genetic basis, we wanted to know whether the family history of urolithiasis is more common in children with UTIs caused by E. coli. Secondarily, we wondered if the renal scars are more common in children with prelithiasis. Ambispective study with collected data from 104 patients (40 male, 64 female) followed after having been diagnosed of UTI by E. coli at least once. These patients were asked about the existence of urolithiasis in relatives. The calcium and citrate urinary elimination was qunatified in 80 children. In the total sample, family history was positive for urolithiasis in a significantly higher frequency in those children (n=71; 68.3%) than in the control population in our area (29.7%; previously published data). Prelithiasis frequency in children with UTI was 47.5% (38/80). An association was observed between the diagnosis of prelithiasis both with family history of urolithiasis (P=.030) and the diagnosis of vesicoureteral reflux (P=.034). Children who developed renal scarring had an increased risk of prelithiasis (OR 5.3; P=.033). The frequency of family history of urolithiasis in children with UTI caused by E. coli is very high. Based on our results we hypothesize that the predisposition to lithiasis can involve a constitutively altered defense to E. coli and, therefore, a greater possibility for renal scars. Copyright © 2017 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

Elevated Vitamin D Receptor Levels in Genetic Hypercalciuric Stone-Forming Rats Are Associated With Downregulation of Snail

PubMed Central

Bai, Shaochun; Wang, Hongwei; Shen, Jikun; Zhou, Randal; Bushinsky, David A; Favus, Murray J

2010-01-01

Patients with idiopathic hypercalciuria (IH) and genetic hypercalciuric stone-forming (GHS) rats, an animal model of IH, are both characterized by normal serum Ca, hypercalciuria, Ca nephrolithiasis, reduced renal Ca reabsorption, and increased bone resorption. Serum 1,25-dihydroxyvitamin D [1,25(OH)2D] levels are elevated or normal in IH and are normal in GHS rats. In GHS rats, vitamin D receptor (VDR) protein levels are elevated in intestinal, kidney, and bone cells, and in IH, peripheral blood monocyte VDR levels are high. The high VDR is thought to amplify the target-tissue actions of normal circulating 1,25(OH)2D levels to increase Ca transport. The aim of this study was to elucidate the molecular mechanisms whereby Snail may contribute to the high VDR levels in GHS rats. In the study, Snail gene expression and protein levels were lower in GHS rat tissues and inversely correlated with VDR gene expression and protein levels in intestine and kidney cells. In human kidney and colon cell lines, ChIP assays revealed endogenous Snail binding close to specific E-box sequences within the human VDR promoter region, whereas only one E-box specifically bound Snail in the rat promoter. Snail binding to rat VDR promoter E-box regions was reduced in GHS compared with normal control intestine and was accompanied by hyperacetylation of histone H3. These results provide evidence that elevated VDR in GHS rats likely occurs because of derepression resulting from reduced Snail binding to the VDR promoter and hyperacetylation of histone H3. © 2010 American Society for Bone and Mineral Research. PMID:19929616

Distal Renal Tubular Acidosis and Calcium Nephrolithiasis

NASA Astrophysics Data System (ADS)

Moe, Orson W.; Fuster, Daniel G.; Xie, Xiao-Song

2008-09-01

Calcium stones are commonly encountered in patients with congenital distal renal tubular acidosis, a disease of renal acidification caused by mutations in either the vacuolar H+-ATPase (B1 or a4 subunit), anion exchanger-1, or carbonic anhydrase II. Based on the existing database, we present two hypotheses. First, heterozygotes with mutations in B1 subunit of H+-ATPase are not normal but may harbor biochemical abnormalities such as renal acidification defects, hypercalciuria, and hypocitraturia which can predispose them to kidney stone formation. Second, we propose at least two mechanisms by which mutant B1 subunit can impair H+-ATPase: defective pump assembly and defective pump activity.

Acidosis and Urinary Calcium Excretion: Insights from Genetic Disorders

PubMed Central

Cordat, Emmanuelle; Chambrey, Régine; Dimke, Henrik; Eladari, Dominique

2016-01-01

Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and inhibition of calcium transport processes within the renal tubule. The mechanisms whereby acid alters the integrity and stability of bone have been examined extensively in the published literature. Here, after briefly reviewing this literature, we consider the effects of acid on calcium transport in the renal tubule and then discuss why not all gene defects that cause renal tubular acidosis are associated with hypercalciuria and nephrocalcinosis. PMID:27468975

Williams-Beuren syndrome associated with single kidney and nephrocalcinosis: a case report.

PubMed

Abidi, Kamel; Jellouli, Manel; Ben Rabeh, Rania; Hammi, Yousra; Gargah, Tahar

2015-01-01

Williams-Beuren syndrome is a rare neurodevelopmental disorder, characterized by congenital heart defects, abnormal facial features, mental retardation with specific cognitive and behavioral profile, growth hormone deficiency, renal and skeletal anomalies, inguinal hernia, infantile hypercalcaemia. We report a case with Williams-Beuren syndrome associated with a single kidney and nephrocalcinosis complicated by hypercalcaemia. A male infant, aged 20 months presented growth retardation associated with a psychomotor impairment, dysmorphic features and nephrocalcinosis. He had also hypercalciuria and hypercalcemia. Echocardiography was normal. DMSA renal scintigraphy showed a single functioning kidney. The FISH generated one ELN signal in 20 metaphases read and found the presence of ELN deletion, with compatible Williams-Beuren syndrome.

Vitamin D-Mediated Hypercalcemia: Mechanisms, Diagnosis, and Treatment

PubMed Central

Tebben, Peter J.; Singh, Ravinder J.

2016-01-01

Hypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)2D], and impaired degradation of 1,25(OH)2D. The ingestion of excessive amounts of vitamin D3 (or vitamin D2) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)2D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)2D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)2D is impaired as a result of mutations of the 1,25(OH)2D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)2D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)2D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)2D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment. PMID:27588937

Amelogenesis imperfecta in familial hypomagnesaemia and hypercalciuria with nephrocalcinosis caused by CLDN19 gene mutations.

PubMed

Yamaguti, Paulo Marcio; Neves, Francisco de Assis Rocha; Hotton, Dominique; Bardet, Claire; de La Dure-Molla, Muriel; Castro, Luiz Claudio; Scher, Maria do Carmo; Barbosa, Maristela Estevão; Ditsch, Christophe; Fricain, Jean-Christophe; de La Faille, Renaud; Figueres, Marie-Lucile; Vargas-Poussou, Rosa; Houillier, Pascal; Chaussain, Catherine; Babajko, Sylvie; Berdal, Ariane; Acevedo, Ana Carolina

2017-01-01

Amelogenesis imperfecta (AI) is a group of genetic diseases characterised by tooth enamel defects. AI was recently described in patients with familial hypercalciuria and hypomagnesaemia with nephrocalcinosis (FHHNC) caused by CLDN16 mutations. In the kidney, claudin-16 interacts with claudin-19 to control the paracellular passage of calcium and magnesium. FHHNC can be linked to mutations in both genes. Claudin-16 was shown to be expressed during amelogenesis; however, no data are available on claudin-19. Moreover, the enamel phenotype of patients with CLDN19 mutations has never been described. In this study, we describe the clinical and genetic features of nine patients with FHHNC carrying CLDN19 mutations and the claudin-19 expression profile in rat ameloblasts. Six FHHNC Brazilian patients were subjected to mutational analysis. Three additional French patients were recruited for orodental characterisation. The expression profile of claudin-19 was evaluated by RT-qPCR and immunofluorescence using enamel epithelium from rat incisors. All patients presented AI at different degrees of severity. Two new likely pathogenic variations in CLDN19 were found: p.Arg200Gln and p.Leu90Arg. RT-qPCR revealed low Cldn19 expression in ameloblasts. Confocal analysis indicated that claudin-19 was immunolocalised at the distal poles of secretory and maturing ameloblasts. For the first time, it was demonstrated that AI is associated with FHHNC in patients carrying CLDN19 mutations. The data suggest claudin-19 as an additional determinant in enamel formation. Indeed, the coexistence of hypoplastic and hypomineralised AI in the patients was consistent with claudin-19 expression in both secretory and maturation stages. Additional indirect systemic effects cannot be excluded. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

A 4-year-old boy presenting with persistent urinary incontinence: Questions.

PubMed

Keenswijk, Werner; Walle, Johan Vande

2017-05-01

A 4-year-old boy was referred to the nephrologist with daytime urinary incontinence and suspicion of an overactive bladder. At the age of 17 months he had been referred to the pediatric endocrinologist because of polyuria and polydipsia in order to exclude diabetes insipidus. Repeated water deprivation tests and a magnetic resonance imaging scan of the brain were normal. Diabetes insipidus was excluded, and primary polydipsia was thought to be most likely since diabetes mellitus also had been excluded. At the current presentation, he drank up to 3 L a day and quite often had wet diapers. He also seemed to pass stools infrequently and with difficulty. Curiously his grandmother had similar symptoms of polyuria and polydipsia since childhood and had been diagnosed with primary polydipsia. The physical examination of our pediatric patient was normal. In the differential diagnosis we included diabetes insipidus but also contemplated other possibilities, such as nephronophthisis, tubulopathies and hypercalciuria. Laboratory results including urinalysis and an ultrasound of the kidney did not show any abnormalities, making a tubulopathy or hypercalciuria unlikely. A desmopressin test by the intravenous route came back completely normal, pointing to another cause than diabetes insipidus. Genetic testing for the nephronophthisis came back negative but was positive for a missense mutation in the AVPR2 gene (p.Arg104Cys) associated with partial nephrogenic diabetes insipidus. He was started on daily desmopressin. Within 3 days the urinary incontinence resolved as did the polyuria and faecal incontinence. His grandmother was referred to the geneticist and eventually the adult nephrologist. This case highlights the importance of being thorough when confronted with a difficult diagnosis. It also emphasizes that a test result does not necessarily equate to the presence or absence of a condition since the test with 100 % sensitivity and specificity has yet to be discovered.

Effect of age and affection status on blood pressure, serum potassium and stature in familial hyperkalaemia and hypertension.

PubMed

Farfel, Alon; Mayan, Haim; Melnikov, Semyon; Holtzman, Eliezer J; Pinhas-Hamiel, Orit; Farfel, Zvi

2011-05-01

The rare autosomal dominant genetic disorder familial hyperkalemia and hypertension which is caused by mutations in WNK4 kinase, is characterized by childhood hyperkalemia and hypercalciuria, and appearance of hypertension in the third to fourth decade. Accompanying short stature is often described. We determined height, blood pressure and blood and urinary biochemical parameters in members of a very large family of FHHt with the WNK4 Q565E mutation. The family has 57 members, 30 of whom (including 14 children) are affected. Prehypertension occurred in 7/11 affected and 1/10 unaffected children (P = 0.024). Serum potassium (SK) was ~0.5 mmol/L higher in affected children vs adults [5.98 ± 0.42 vs 5.46 ± 0.40 mmol/L, respectively (P < 0.0001)] (33 samples from 11 children and 36 samples from eight adults). SK of ≥ 6.0 mmol/L occurred in 16/33 children's samples and in 3/36 adults' samples (P = 0.0003). Hyperkalaemia in children is currently untreated. Children also had more severe hyperchloraemia and hypercalciuria. The family contains four large subfamilies, and each includes 8-10 siblings. In one subfamily, height Z-score was lower in affected vs unaffected subjects [- 2.69 ± 0.36 vs -1.05 ± 0.16, respectively (P < 0.0001)]. In the other three subfamilies, no such difference was found. Short stature is not part of FHHt with the WNK4 Q565E mutation. Children affected with FHHt have a high prevalence of prehypertension, and their hyperkalaemia is more severe than that of affected adults. Children may have a more severe defect in the basic mechanism that produces hyperkalaemia. We suggest that, in affected adults, the attenuation of hyperkalaemia and appearance of hypertension may be the result of a late rise in the activity of renal transporters or channels such as the epithelial sodium channel.

Evolution of post-ESWL residual lithiasis depending on the type of calculus and urine composition.

PubMed

Grases, Felix; Costa-Bauzá, Antonia; Isern, Bernat; Sanchis, Pilar; Perelló, Joan; Hierro, Fernando; Conte Visus, Antonio

2009-07-01

Extracorporeal shock wave lithotripsy (ESWL) is one of the most commonly used procedures for removal of renal calculi from the upper urinary tract, but complete expulsion of the fragments generated is not always achieved. This can lead to new lithiasic episodes, and it is considered that 10-26% of fragmented calculi can undergo regrowth. This in vitro study investigated the influence of fragment and urinary composition on post-ESWL growth of fragments, with the aims of establishing the effect and importance of these parameters, and identifying effective prophylactic measures. Fragments collected from patients immediately following expulsion after ESWL treatment were selected for regrowth experiments. The particles included 24 calcium oxalate monohydrate (COM) fragments, 48 calcium oxalate dihydrate (COD), 24 hydroxyapatite (HAP), and 16 uric acid. In all treatments, calculi fragments showed a considerable capacity to induce growth of calcium oxalate and calcium phosphate. Under normocalciuria conditions, new COM crystals formed; both COM and COD crystals developed under hypercalciuria conditions at a urinary pH < 6.0; and in hypercalciuric conditions and urinary pH > 6.0 both HAP and brushite (BRU) crystals were formed. The highest growth rates were observed for COD calculi fragments under hypercalciuria conditions and at a urinary pH of 6.5, followed by growth on COM and HAP fragments under the same conditions; growth rates under other conditions tested were similar but 10-fold lower. With regard to the role of crystallization inhibitors, phytate exhibited inhibitory effects under all assay conditions. However, citrate had little effect, even at the highest concentration tested (1,000 mg/L). This study demonstrates the importance of avoiding heterogeneous nucleant retention (pre-existing solid microparticles) in renal cavities, as these can act as very efficient inducers of the formation of new calculi, the composition of which is mainly dependant on the urine composition.

Impaired bone formation in male idiopathic osteoporosis: further reduction in the presence of concomitant hypercalciuria

NASA Technical Reports Server (NTRS)

Zerwekh, J. E.; Sakhaee, K.; Breslau, N. A.; Gottschalk, F.; Pak, C. Y.

1992-01-01

We present iliac bone histomorphometric data and related biochemical data from 16 nonalcoholic men (50 +/- 11 (SD) years) referred for evaluation of spontaneous skeletal and/or appendicular fractures and reduced spinal bone density. All men were eugonadal and had no known underlying disorder associated with osteopenia. For the group, mean serum chemistry values were within normal limits including immunoreactive parathyroid hormone, osteocalcin and serum 1,25-dihydroxyvitamin D [1,25(OH)2D]. Nine men demonstrated hypercalciuria (greater than or equal to 0.1 mmol/kg per day) while on a constant metabolic diet of 20 mmol/day Ca. Their 24-hour urinary calcium was significantly greater than that for the remaining 7 men (7.4 +/- 1.6 vs. 5.0 +/- 0.8 mmol/day, p = 0.003), as was their calciuric response to a 1 g oral calcium load (0.23 +/- 0.06 vs. 0.15 +/- 0.05 Ca/creatinine, p = 0.042). Serum parameters (including parathyroid hormone and 1,25(OH)2D) of hypercalciuric and normocalciuric men were not significantly different. Histomorphometric indices for cancellous bone demonstrated significant differences between the entire group of osteoporotic men and age-adjusted normal values for bone volume (11.4 +/- 4.0% vs. 23.2 +/- 4.4%), osteoid surface (5.6 +/- 3.9% vs. 12.1 +/- 4.6%), osteoblastic surface (2.0 +/- 2.3% vs. 3.9 +/- 1.9%), and mineralizing surface (1.9 +/- 2.4% vs. 5.1 +/- 2.7%); there were also significant differences in bone formation rate (total surface referent) (0.004 +/- 0.001 vs. 0.011 +/- 0.006 mm3/mm2 per year). Compared with the normocalciuric group the 9 hypercalciuric men had significantly lower osteoblastic surfaces (1.6 +/- 1.9% vs. 2.5 +/- 2.6%) and mineralizing surfaces (1.4 +/- 1.5% vs. 2.7 +/- 3.2%).(ABSTRACT TRUNCATED AT 250 WORDS).

Skeletal Collagen Turnover by the Osteoblast

NASA Technical Reports Server (NTRS)

Partridge, Nicola C.

1997-01-01

Among the most overt negative changes experienced by man and experimental animals under conditions of weightlessness are the loss of skeletal mass and attendant hypercalciuria. These clearly result from some disruption in the balance between bone formation and bone resorption (i.e. remodelling) which appears to be due to a decrease in the functions of the osteoblast. In the studies funded by this project, the clonal osteoblastic cell line, UMR 106-01, has been used to investigate the regulation of collagenase and Tissue Inhibitors of MetalloProteases (TIMPs). This project has shed light on the comprehensive role of the osteoblast in the remodelling process, and, in so doing, provided some insight into how the process might be disrupted under conditions of microgravity.

Effects of diet on urine composition of cats with calcium oxalate urolithiasis.

PubMed

Lulich, Jody P; Osborne, Carl A; Lekcharoensuk, Chalermpol; Kirk, Claudia A; Bartges, Joseph W

2004-01-01

Ten client-owned cats with calcium oxalate (CaOx) urolithiasis were evaluated to determine the effect of diet on urine CaOx saturation. Two dietary treatments were evaluated in each cat: the diet consumed just prior to urolith detection and a canned diet formulated to prevent CaOx uroliths. This study revealed that hypercalciuria is a consistent abnormality in cats with CaOx urolith formation. When urolith-forming cats consumed a diet formulated to prevent urolith formation, activity product ratios for CaOx (which estimate the degree to which urine is saturated with CaOx) were significantly lower. These results suggest that consumption of an appropriately formulated urolith-prevention diet will reduce recurrence of CaOx urolithiasis.

[Hereditary hypophosphatemia in adults].

PubMed

Vélayoudom-Céphise, F-L; Vantyghem, M-C; Wémeau, J-L

2005-12-17

Hereditary hypophosphatemic rickets groups together X-linked hypophosphatemic rickets (XLH), autosomal dominant hypophosphatemic rickets (ADHR) and hereditary hypophosphatemic rickets with hypercalciuria (HHRH, autosomal recessive). Clinical and biological characteristics and treatment depend on specific etiology. Mutations causing hereditary hypophosphatemic rickets involve PHEX located on Xp11.22 for XLH and FGF-23 located on 12p13 for ADHR. The gene involved in HHRH remains unknown: candidates may encode proteins that modulate phosphate transporter expression or activity. Others forms of rickets must be ruled out: acquired hypophosphatemia due to oncogenic osteomalacia, X-linked recessive hypophosphatemic rickets or Dent's disease, and hereditary 1, 25-dihydroxyvitamin D-resistant rickets with a defect either in the 1-alpha-hydroxylase gene (pseudo-vitamin D deficiency rickets, PDDR) or in the vitamin D receptor (hereditary vitamin D-resistant rickets, HVDRR).

Comparison of 2 weight-loss diets of different protein content on bone health: a randomized trial.

PubMed

Jesudason, David; Nordin, Be Christopher; Keogh, Jennifer; Clifton, Peter

2013-11-01

It has been hypothesized that hip-fracture rates are higher in developed than in developing countries because high-protein (HP) Western diets induce metabolic acidosis and hypercalciuria. Confounders include interactions between dietary protein and calcium, sodium, and potassium. We determined whether an HP or a high-normal-protein (HNP) weight-loss diet caused greater loss in bone mineral density (BMD) over 24 mo. The Weight Loss, Protein and Bone Density Study was conducted from 2008 to 2011 in 323 overweight [body mass index (BMI; in kg/m(2)) >27] postmenopausal women, with a total hip BMD t score less than -2.0. Subjects were randomly assigned to receive an isocaloric calcium-replete HP (≥90 g protein/d) or HNP (<80 g protein/d) weight-loss diet, with the aim of a difference of 20 g protein/d. A total of 186 subjects (90 subjects in the HP group, 96 subjects in the HNP group) completed 12 mo, and 137 subjects (69 subjects in the HP group, 68 subjects in the HNP group) completed 24 mo. Biomarkers confirmed a difference in protein intake of 16 and 13.1 g at 12 and 24 mo, respectively. Mean (±SE) weight loss was equal; HP subjects lost 7.9 ± 0.9 kg and HNP subjects lost 8.9 ± 0.9 kg at 24 mo. Subjects lost 1-2% BMD annually at lumbar spine vertebrae 2-4, the forearm, the femoral neck, and hip. ANCOVA showed no effect of the HP or HNP diet (P > 0.05 for diet and diet-time interactions). A diet-by-time analysis showed that the HNP diet increased C-terminal telopeptide and osteocalcin (P ≤ 0.001 for each) despite hypercalciuria (P = 0.029). High dietary protein intake during weight loss has no clinically significant effect on bone density but slows bone turnover. This trial was registered at the Australian and New Zealand Clinical Trials Registry (http://www.anzctr.org.au) as ACTRN12608000229370.

Association between Circulating Vitamin D Level and Urolithiasis: A Systematic Review and Meta-Analysis.

PubMed

Hu, Henglong; Zhang, Jiaqiao; Lu, Yuchao; Zhang, Zongbiao; Qin, Baolong; Gao, Hongbin; Wang, Yufeng; Zhu, Jianning; Wang, Qing; Zhu, Yunpeng; Xun, Yang; Wang, Shaogang

2017-03-18

Many studies compared the serum/plasma 1,25 dihydroxyvitamin D₃ (1,25(OH)₂D) and 25 hydroxyvitamin D₃ (25(OH)D) between people with and without nephrolithiasis, and their results were conflicting. After systematically searching PubMed, Web of Science, The Cochrane Library, CNKI, and the Wanfang Database, we conducted a meta-analysis. Thirty-two observational studies involving 23,228 participants were included. Meta-analysis of these studies showed that of stone formers (SFs), calcium SFs had significantly higher concentrations of 1,25(OH)₂D (weighted mean difference (WMD), 10.19 pg/mL; 95% confidence interval (CI), 4.31-16.07; p = 0.0007 and WMD, 11.28 pg/mL; 95% CI, 4.07-18.50; p = 0.002, respectively) than non-stone formers, while the levels of 25(OH)D (WMD, 0.88 ng/mL; 95% CI, -1.04-2.80; p = 0.37 and WMD, -0.63 ng/mL; 95% CI, -2.72-1.47; p = 0.56, respectively) are similar. Compared with controls and normocalciuria SFs, hypercalciuria SFs had increased circulating 1,25(OH)₂D (WMD, 9.41 pg/mL; 95% CI, 0.15-18.67; p = 0.05 and WMD, 2.75 pg/mL; 95% CI, -0.20-5.69; p = 0.07, respectively) and markedly higher 25(OH)D (WMD, 5.02 ng/mL; 95% CI, 0.99-9.06; p = 0.01 and WMD, 5.02 ng/mL; 95% CI, 2.14-7.90; p = 0.0006, respectively). Normocalciuria SFs had elevated 1,25(OH)₂D level (WMD, 6.85 pg/mL; 95% CI, -5.00-18.71; p = 0.26) and comparable 25(OH)D (WMD, 0.94 ng/mL; 95% CI, -3.55-5.43; p = 0.68). Sensitivity analysis generated similar results. Current evidence suggests that increased circulating 1,25(OH)₂D is associated with urinary stones and a higher level of circulating 25(OH)D is significantly associated with hypercalciuria urolithiasis. Further studies are still needed to reconfirm and clarify the role of vitamin D in the pathogenesis of stones.

High sodium chloride intake is associated with low bone density in calcium stone-forming patients.

PubMed

Martini, L A; Cuppari, L; Colugnati, F A; Sigulem, D M; Szejnfeld, V L; Schor, N; Heilberg, I P

2000-08-01

Although renal stone disease has been associated with reduced bone mass, the impact of nutrient intake on bone loss is unknown. The present study was undertaken to investigate the influence of nutrient intake on bone density of 85 calcium stone-forming (CSF) patients (47 male and 38 premenopausal females) aged 41+/-11 years (X+/-SD). Bone mineral density (BMD) was measured using dual energy X-ray absorptiometry at the lumbar spine (L2-L4) and femoral neck sites, and low BMD was defined as a T score < -1 (WHO criteria). A 4-day dietary record and a 24-hour urine sample were obtained from each patient for the assessment of nutrient intake and urinary calcium (U(Ca)), sodium (U(Na)), phosphate and creatinine excretion. Forty-eight patients (56%) presented normal BMD and 37 (44%) low BMD. There were no statistical differences regarding age, weight, height, body mass index, protein, calcium and phosphorus intakes between both groups. The mean U(Ca), phosphorus and nitrogen appearance also did not differ between groups. However, there was a higher percentage of hypercalciuria among low vs normal BMD patients (62 vs 33%, p < 0.05). Low BMD patients presented a higher mean sodium chloride (NaCl) intake and excretion (UNa) than normal BMD (14+/-5 vs 12+/-4 g/day and 246+/-85 vs 204+/-68 mEq/day, respectively p < 0.05). The percentage of patients presenting NaCl intake > or = 16 g/day was also higher among low vs normal BMD patients (35 vs 12%, p < 0.05). After adjustment for calcium and protein intakes, age, weight, body mass index, urinary calcium, citrate and uric acid excretion, and duration of stone disease, multiple-regression analysis showed that a high NaCl intake (> or = 16 g/day) was the single variable that was predictive of risk of low bone density in CSF patients (odds ratio = 3.8). These data suggest that reducing salt intake should be recommended for CSF patients presenting hypercalciuria and osteopenia.

Prostaglandin-E2 Mediated Increase in Calcium and Phosphate Excretion in a Mouse Model of Distal Nephron Salt Wasting

PubMed Central

Soleimani, Manoocher; Barone, Sharon; Xu, Jie; Alshahrani, Saeed; Brooks, Marybeth; McCormack, Francis X.; Smith, Roger D.; Zahedi, Kamyar

2016-01-01

Contribution of salt wasting and volume depletion to the pathogenesis of hypercalciuria and hyperphosphaturia is poorly understood. Pendrin/NCC double KO (pendrin/NCC-dKO) mice display severe salt wasting under basal conditions and develop profound volume depletion, prerenal renal failure, and metabolic alkalosis and are growth retarded. Microscopic examination of the kidneys of pendrin/NCC-dKO mice revealed the presence of calcium phosphate deposits in the medullary collecting ducts, along with increased urinary calcium and phosphate excretion. Confirmatory studies revealed decreases in the expression levels of sodium phosphate transporter-2 isoforms a and c, increases in the expression of cytochrome p450 family 4a isotypes 12 a and b, as well as prostaglandin E synthase 1, and cyclooxygenases 1 and 2. Pendrin/NCC-dKO animals also had a significant increase in urinary prostaglandin E2 (PGE-2) and renal content of 20-hydroxyeicosatetraenoic acid (20-HETE) levels. Pendrin/NCC-dKO animals exhibit reduced expression levels of the sodium/potassium/2chloride co-transporter 2 (NKCC2) in their medullary thick ascending limb. Further assessment of the renal expression of NKCC2 isoforms by quantitative real time PCR (qRT-PCR) reveled that compared to WT mice, the expression of NKCC2 isotype F was significantly reduced in pendrin/NCC-dKO mice. Provision of a high salt diet to rectify volume depletion or inhibition of PGE-2 synthesis by indomethacin, but not inhibition of 20-HETE generation by HET0016, significantly improved hypercalciuria and salt wasting in pendrin/NCC dKO mice. Both high salt diet and indomethacin treatment also corrected the alterations in NKCC2 isotype expression in pendrin/NCC-dKO mice. We propose that severe salt wasting and volume depletion, irrespective of the primary originating nephron segment, can secondarily impair the reabsorption of salt and calcium in the thick ascending limb of Henle and/or proximal tubule, and reabsorption of sodium and phosphate in the proximal tubule via processes that are mediated by PGE-2. PMID:27442254

Hereditary Causes of Kidney Stones and Chronic Kidney Disease

PubMed Central

Edvardsson, Vidar O.; Goldfarb, David S.; Lieske, John C.; Beara-Lasic, Lada; Anglani, Franca; Milliner, Dawn S.; Palsson, Runolfur

2013-01-01

Adenine phosphoribosyltransferase (APRT) deficiency, cystinuria, Dent disease, familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) and primary hyperoxaluria (PH) are rare but important causes of severe kidney stone disease and/or chronic kidney disease in children. Recurrent kidney stone disease and nephrocalcinosis, particularly in pre-pubertal children, should alert the physician to the possibility of an inborn error of metabolism as the underlying cause. Unfortunately, the lack of recognition and knowledge of the five disorders has frequently resulted in an unacceptable delay in diagnosis and treatment, sometimes with grave consequences. A high index of suspicion coupled with early diagnosis may reduce or even prevent the serious long-term complications of these diseases. In this paper, we review the epidemiology, clinical features, diagnosis, treatment and outcome of patients with APRT deficiency, cystinuria, Dent disease, FHHNC and PH with emphasis on childhood manifestations. PMID:23334384

Alterations in renal stone risk factors after space flight

NASA Technical Reports Server (NTRS)

Whitson, P. A.; Pietrzyk, R. A.; Pak, C. Y.; Cintron, N. M.

1993-01-01

Exposure to the microgravity environment of space produces a number of physiological changes of metabolic and environmental origin that could increase the potential for renal stone formation. Metabolic, environmental and physicochemical factors that influence renal stone risk potential were examined in 24-hour urine samples from astronauts 10 days before launch and on landing day to provide an immediate postflight assessment of these factors. In addition, comparisons were made between male and female crewmembers, and between crewmembers on missions of less than 6 days and those on 6 to 10-day missions. Results suggest that immediately after space flight the risk of calcium oxalate and uric acid stone formation is increased as a result of metabolic (hypercalciuria, hypocitraturia, pH) and environmental (lower urine volume) derangements, some of which could reflect residual effects of having been exposed to microgravity.

Hypercalcemia due to hypervitaminosis D: report of seven patients.

PubMed

Joshi, Rajesh

2009-12-01

We retrospectively studied seven children (six girls, one boy) aged from 7.5 to 25 months who presented to our institution after taking large doses of vitamin D (900 000-4 000 000 U) prescribed by medical practitioners for wrong indications like failure to thrive, etc. The clinical manifestations were constipation, decreased appetite, lethargy, polyuria, dehydration and failure to thrive. All patients had hypercalcemia (serum calcium ranging from 12 to 16.8 mg/dl), high 25[OH]D levels (ranging from 96 to >150 ng/ml), suppressed intact parathyroid hormone (ranging from <3 to 8.1 pg/ml). Hypercalciuria (urinary calcium/creatinine ranging from 1 to 2.45) was found in all patients, while nephrocalcinosis was present in five patients. All were treated with intravenous fluids, oral prednisolone, restriction of calcium in diet, while four patients received pamidronate infusion for reducing hypercalcemia.

[Assessment of the risk factors for urolithiasis in cosmonauts during long flights

NASA Technical Reports Server (NTRS)

Arzamazov, G. S.; Witson, P. A.; Larina, O. N.; Pastushkova, L. Kh; Pak, C. T.; Whitson, P. A. (Principal Investigator)

1996-01-01

Twelve cosmonauts flown aboard the Mir orbital station for 6-12 months and twelve candidates for cosmonauts were examined in an effort to determine a degree of urolithiasis risk. Prior to flight, on flight day 310 (in one cosmonaut) and after flight, the daily urinary excretion of the components influencing lithiasis formation was determined as well as a computer-aided calculation of urine saturation by lithogenic salts was performed (Ch. Pak, USA). In the in- and postflight periods, the greater number of indices under study were negatively changed in cosmonauts. Excretion dynamics of the lithogenesis inhibitors, i.e., citrates and magnesium, is of polar directionality. Frequency of deviations from the normal indices of urolithic risk in cosmonauts is primarily conditioned by low diuresis, urine supersaturation with calcium oxalate, undissociated uric acid, brushit, hypercalciuria, and changed pH.

Necrotizing crescentic glomerulonephritis related to sarcoidosis: a case report.

PubMed

Maroz, Natallia; Field, Halle

2015-12-14

Renal injury due to sarcoidosis develops in less than a quarter of patients with this systemic disease. In most cases, granulomatous tissue alters the production of vitamin D, which leads to hypercalciuria, nephrocalcinosis, and nephrolithiasis. Granulomatous interstitial nephritis is another well-recognized pathological process associated with sarcoidosis. However, a glomerular pathology is very rarely noted, and only a few cases are reported to have cellular crescentic glomerulonephritis. We describe the case of a 26-year-old African American woman with systemic sarcoidosis, with a unique constellation of renal lesions, including noncaseating epithelioid granulomatous necrotizing interstitial nephritis, cellular crescent formation, and necrotizing vasculitis. Immunosuppressive therapy was helpful for alleviating her nephrotic syndrome and maintaining the stability of her renal function over a 30-month period. Glomerular involvement of sarcoidosis needs to be considered in the differential diagnosis in cases of rapidly progressive glomerular nephritis.

Space medicine considerations: Skeletal and calcium homeostasis

NASA Technical Reports Server (NTRS)

Schneider, Victor B.

1989-01-01

Based on the information obtained from space missions, particularly Skylab and the longer Salyut missions, it is clear that bone and mineral metabolism is substantially altered during space flight. Calcium balance becomes increasingly more negative throughout the flight, and the bone mineral content of the os calcis declines. The major health hazards associated with skeletal changes include the signs and symptoms of hypercalcemia with rapid bone turnover, the risk of kidney stones because of hypercalciuria, the lengthy recovery of lost bone mass after flight, the possibility of irreversible bone loss (particularly the trabecular bone), the possible effects of metastated calcification in the soft tissues, and the possible increase in fracture potential. For these reasons, major efforts need to be directed toward elucidating the fundamental mechanisms by which bone is lost in space and developing more effective countermeasures to prevent both short-term and long-term complications.

Bartter Syndrome Type 1 Presenting as Nephrogenic Diabetes Insipidus

PubMed Central

Fabbri, Elena; Pedini, Annalisa; Tedeschi, Silvana; Borsa, Niccolò

2018-01-01

Bartter syndrome (BS) type 1 (OMIM #601678) is a hereditary salt-losing renal tubular disorder characterized by hypokalemic metabolic alkalosis, hypercalciuria, nephrocalcinosis, polyuria, recurrent vomiting, and growth retardation. It is caused by loss-of-function mutations of the SLC12A1 gene, encoding the furosemide-sensitive Na-K-Cl cotransporter. Recently, a phenotypic variability has been observed in patients with genetically determined BS, including absence of nephrocalcinosis, hypokalemia, and/or metabolic alkalosis in the first year of life as well as persistent metabolic acidosis mimicking distal renal tubular acidosis. We report the case of a child with a genetically determined diagnosis of Bartter syndrome type 1 who presented with a phenotype of nephrogenic diabetes insipidus, with severe hypernatremia and urinary concentrating defect. In these atypical cases, molecular analysis is mandatory to define the diagnosis, in order to establish the correct clinical and therapeutic management. PMID:29527380

Bartter Syndrome Type 1 Presenting as Nephrogenic Diabetes Insipidus.

PubMed

Vergine, Gianluca; Fabbri, Elena; Pedini, Annalisa; Tedeschi, Silvana; Borsa, Niccolò

2018-01-01

Bartter syndrome (BS) type 1 (OMIM #601678) is a hereditary salt-losing renal tubular disorder characterized by hypokalemic metabolic alkalosis, hypercalciuria, nephrocalcinosis, polyuria, recurrent vomiting, and growth retardation. It is caused by loss-of-function mutations of the SLC12A1 gene, encoding the furosemide-sensitive Na-K-Cl cotransporter. Recently, a phenotypic variability has been observed in patients with genetically determined BS, including absence of nephrocalcinosis, hypokalemia, and/or metabolic alkalosis in the first year of life as well as persistent metabolic acidosis mimicking distal renal tubular acidosis. We report the case of a child with a genetically determined diagnosis of Bartter syndrome type 1 who presented with a phenotype of nephrogenic diabetes insipidus, with severe hypernatremia and urinary concentrating defect. In these atypical cases, molecular analysis is mandatory to define the diagnosis, in order to establish the correct clinical and therapeutic management.

Hypophosphatemic rickets with hypocalciuria following long-term treatment with aluminum-containing antacid.

PubMed

Foldes, J; Balena, R; Ho, A; Parfitt, A M; Kleerekoper, M

1991-01-01

We present what we believe is the first case of rickets following prolonged treatment with aluminum containing antacids that bind phosphate, in an 18-year-old mentally retarded boy with cerebral palsy and spastic quadriplegia. As expected, serum calcitriol was increased and urinary phosphate excretion was very low. However, in contrast to all published cases of antacid induced hypophosphatemic osteomalacia in adults, despite a substantial increase in bone resorption reflected by urinary total hydroxyproline excretion, urinary calcium excretion was low rather than high, and significant hypocalcemia occurred after antacids were ceased and a phosphate salt administered. We suggest that the skeleton was so under-mineralized because of growth during prolonged phosphate deficiency, possibly augmented by anticonvulsant administration and immobilization, that increased bone resorption did not release enough calcium to cause hypercalciuria, or to prevent hypocalcemia during resumption of normal mineralization.

[Calcium and magnesium concentrations in "Healthy" and lithiasic human kidney (author's transl)].

PubMed

Terhorst, B; Stoeppler, M

1976-07-01

Calcium and magnesium levels in the cortex, medulla, and papilla of human kidney from 32 so-called healthy patients and from eleven patients with calcium-oxalate lithiasis were determined by atom-absorption spectralphotometry. A positive calcium gradient with the highest calcium concentration in the papilla was found in all kidneys. Compared to the control group, that calcium concentration in the lithiasic kidneys was reduced by 50% in the papilla, but in the cortex and medulla, the levels were the same. A relative depletion of calcium in the papilla in hypercalciuria goes against the theory that the papilla is the main center of development of calcium-containing stones. The magnesium concentration was practically the same in cortex, medulla, and papilla, and no significant difference was found between lithiasic and healthy kidneys. These findings underline the central role of calcium in the genesis of calcium-containing stones.

Characterization of Microgravity Effects on Bone Structure and Strength Using Fractal Analysis

NASA Technical Reports Server (NTRS)

Acharya, Raj S.; Shackelford, Linda

1996-01-01

Protecting humans against extreme environmental conditions requires a thorough understanding of the pathophysiological changes resulting from the exposure to those extreme conditions. Knowledge of the degree of medical risk associated with the exposure is of paramount importance in the design of effective prophylactic and therapeutic measures for space exploration. Major health hazards due o musculoskeletal systems include the signs and symptoms of hypercalciuria, lengthy recovery of lost bone tissue after flight, the possibility of irreversible trabecular bone loss, the possible effect of calcification in the soft tissues, and the possible increase in fracture potential. In this research, we characterize the trabecular structure with the aid of fractal analysis. Our research to relate local trabecular structural information to microgravity conditions is an important initial step in understanding the effect of microgravity and countermeasures on bone condition and strength. The proposed research is also closely linked with Osteoporosis and will benefit the general population.

Changes in urinary risk profile after short-term low sodium and low calcium diet in recurrent Swiss kidney stone formers.

PubMed

Seeger, Harald; Kaelin, Andrea; Ferraro, Pietro M; Weber, Damian; Jaeger, Philippe; Ambuehl, Patrice; Robertson, William G; Unwin, Robert; Wagner, Carsten A; Mohebbi, Nilufar

2017-12-04

Kidney stone disease is common in industrialized countries. Recently, it has attracted growing attention, because of its significant association with adverse renal outcomes, including end stage renal disease. Calcium-containing kidney stones are frequent with high recurrence rates. While hypercalciuria is a well-known risk factor, restricted intake of animal protein and sodium, combined with normal dietary calcium, has been shown to be more effective in stone prevention compared with a low-calcium diet. Notably, the average sodium intake in Switzerland is twice as high as the WHO recommendation, while the intake of milk and dairy products is low. We retrospectively analyzed Swiss recurrent kidney stone formers (rKSF) to test the impact of a low-sodium in combination with a low-calcium diet on the urinary risk profile. In patients with recurrent calcium oxalate containing stones, we investigated both, the consequence of a low-sodium diet on urinary volume and calcium excretion, and the influence of a low-sodium low-calcium diet on urinary oxalate excretion. Of the 169 patients with CaOx stones, 49 presented with hypercalciuria at baseline. The diet resulted in a highly significant reduction in 24-h urinary sodium and calcium excretion: from 201 ± 89 at baseline to 128 ± 88 mmol/d for sodium (p < 0.0001), and from 5.67 ± 3.01 to 4.06 ± 2.46 mmol/d (p < 0.0001) for calcium, respectively. Urine volume remained unchanged. Notably, no increase in oxalate excretion occurred on the restricted diet (0.39 ± 0.26 vs 0.39 ± 0.19 mmol/d, p = 0.277). Calculated Psf (probability of stone formation) values were only predictive for the risk of calcium phosphate stones. A diet low in sodium and calcium in recurrent calcium oxalate stone formers resulted in a significant reduction of urinary calcium excretion, but no change in urine volume. In this population with apparently low intake of dairy products, calcium restriction does not necessarily result in increased urinary oxalate excretion. However, based on previous studies, we recommend a normal dietary calcium intake to avoid a potential increase in urinary oxalate excretion and unfavorable effects on bone metabolism in hypercalciuric KSFs.

Vitamin D intervention in preschoolers with viral-induced asthma (DIVA): a pilot randomised controlled trial.

PubMed

Jensen, Megan E; Mailhot, Genevieve; Alos, Nathalie; Rousseau, Elizabeth; White, John H; Khamessan, Ali; Ducharme, Francine M

2016-07-26

Trials in school-aged children suggest vitamin D supplementation reduces asthma exacerbations. Primary aim: to examine whether vitamin D3 (100,000 IU) rapidly raises serum 25-hydroxyvitamin D (25OHD) ≥75 nmol/L in asthmatic preschoolers. In a double-blind, randomised, placebo-controlled trial, preschool-aged children with asthma received 100,000 IU vitamin D3 (intervention) or placebo (control), followed by 400 IU vitamin D3 daily for 6 months. Serum 25OHD was measured at baseline, 10 days, 3 and 6 months. Outcomes included the group difference in 25OHD change from baseline at 3 months (Δ25OHD); the proportion of children with 25OHD ≥75 nmol/L at 3 months; the pattern in serum vitamin D over 6 months; the proportion of children with hypercalciuria at any time point (safety); and group rates for oral corticosteroids. Continuous outcomes were analysed using generalised linear mixed models and group rate ratios of events per child were assessed using a Poisson distribution model. Twenty-two children were randomised (intervention:11; control:11) during winter. At 3 months, the group difference in Δ25OHD (7.2 nmol/L; 95 % CI: -13.7, 28.1) was not significant; yet, 100 % versus 54.5 % (intervention versus control) had serum 25OHD ≥75 nmol/L. There was a significant group difference in Δ25OHD at 10 days (110.3 nmol/L; 95 % CI: 64.0, 156.6). One child in each group had transient hypercalciuria at 10 days. Group oral corticosteroids rates were 0.82 and 1.18/child, intervention versus control (rate ratio = 0.68; 95 % CI: 0.30, 1.62; non-significant). Following 100,000 IU vitamin D3, all children reached serum 25OHD ≥75 nmol/L, compared with half who received placebo. Daily supplementation, sun exposure and insufficient power may explain the absence of a significant 3-month group difference in Δ25OHD. No clinically important alterations in bone metabolism biomarkers occurred. Group oral corticosteroid rates will inform sample size calculations for the larger trial. ( NCT01999907 , 25 November 2013).

[A clinical and hereditary analysis of novel complex heterozygous KCNJ1 mutation in a Bartter syndrome type Ⅱ patient].

PubMed

Li, X Y; Jiang, Y; Xu, L J; Duan, L; Peng, X Y; Chen, L M; Xia, W B; Xing, X P

2017-10-01

Bartter syndrome (BS) is a hereditary condition transmitted as an autosomal recessive (Bartter type 1 to 4) or dominant trait (Bartter type 5). The disease associates hypokalemic alkalosis with varying degrees of hypercalciuria. Here we presented a case (BS type Ⅱ) of a 17 years old female presented with polyhydramnios, polyuria, nephrocalcinosis and hypokalemia, which was alleviated after treatment with celecoxib and vitamin D(3). DNA sequencing identified compound heterozygous KCNJ 1 gene mutations, c. 931C >T (p.R311W) and c. 445-446insCCTGAACAC (p.V149Afs, 150X), with the latter a novel mutation. Her father and mother were heterozygous carriers of c. 931C >T (p.R311W) and c. 445-446insCCTGAACAC (p.V149Afs, 150X), respectively. In conclusion, this case of BS type Ⅱ is caused by a novel compound heterozygous KCNJ 1 mutation. Further studies are needed to verify the effect of celecoxib in BS patients.

Localization of a renal sodium-phosphate cotransporter gene to human chromosome 5q35

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

Kos, C.H.; Tenenhouse, H.S.; Tihy, F.

1994-01-01

Several Mendelian disorders of renal phosphate reabsorption, associated with hypophosphatemia and bone disease, have been described. These include X-linked hypophosphatemia (XLH), hereditary hypophosphatemic rickets with hypercalciuria, hypophosphatemic bone disease, and autosomal dominant and autosomal recessive hypophosphatemic rickets. The underlying mechanisms for renal phosphate wasting in these disorders remain unknown. The proximal tubule is the major site of renal phosphate reabsorption. Thus, mutations in genes that participate in the transepithelial transport of phosphate in this segment of the nephron may be responsible for these disorders. Recently, a cDNA encoding a renal proximal tubular, brush-border membrane Na[sup +]-phosphate cotransporter (NaP[sub i]-3) wasmore » cloned from human kidney cortex. As a first step in establishing whether mutations in the NaP[sub i]-3 gene are the cause of inherited disorders in phosphate homeostasis, the authors sought to determine its chromosomal localization. 9 refs., 1 fig.« less

Prevention of bone mineral changes induced by bed rest: Modification by static compression simulating weight bearing, combined supplementation of oral calcium and phosphate, calcitonin injections, oscillating compression, the oral diophosphonatedisodium etidronate, and lower body negative pressure

NASA Technical Reports Server (NTRS)

Schneider, V. S.; Hulley, S. B.; Donaldson, C. L.; Vogel, J. M.; Rosen, S. N.; Hantman, D. A.; Lockwood, D. R.; Seid, D.; Hyatt, K. H.; Jacobson, L. B.

1974-01-01

The phenomenon of calcium loss during bed rest was found to be analogous to the loss of bone material which occurs in the hypogravic environment of space flight. Ways of preventing this occurrence are investigated. A group of healthy adult males underwent 24-30 weeks of continuous bed rest. Some of them were given an exercise program designed to resemble normal ambulatory activity; another subgroup was fed supplemental potassium phosphate. The results from a 12-week period of treatment were compared with those untreated bed rest periods. The potassium phosphate supplements prevented the hypercalciuria of bed rest, but fecal calcium tended to increase. The exercise program did not diminish the negative calcium balance. Neither treatment affected the heavy loss of mineral from the calcaneus. Several additional studies are developed to examine the problem further.

Urolithiasis in Tennessee: an occupational window into a regional problem.

PubMed Central

Thun, M J; Schober, S

1991-01-01

BACKGROUND: Urinary tract stones (stones) are believed to be unusually common in the southeastern United States but neither the incidence of nor the risk factors for stones are known. METHODS: In three well-defined occupational populations in eastern Tennessee, we assessed the prevalence, incidence, and cumulative incidence of stones and measured biochemical risk factors for lithogenesis. RESULTS: The age-adjusted prevalence of stones was 18.5 percent in Tennessee compared to 7.7 percent among White males in US NHANES (prevalence ratio 2.4, 95% CI 1.7, 3.3). The cumulative incidence (risk) was 27.8 percent by age 65, higher than in any other reported population. Risk factors were age, a family history, and urinary saturation with calcium-oxalate (COAX). Persons with a positive family history and the highest measured CAOX index had a predicted lifetime risk of 88.8 percent. Biochemical factors affecting lithogenesis were hypercalciuria, hyperoxaluria, and low urine volume. CONCLUSION: Future research should characterize the geographic boundaries of a southeastern "stone-belt" and explore genetic and dietary hypotheses that might explain it. PMID:2014858

Quantitative Mineralogical Composition of Calculi and Urine Abnormalities for Calcium Oxalate Stone Formers: A Single-Center Results.

PubMed

Kustov, Andrey V; Strelnikov, Alexander I

2018-05-03

The paper focuses on the relationship of risk factors and metabolic disorders with mineralogical composition of calculi, age and gender of calcium oxalate stone formers. Stone mineralogical composition, 24 hour biochemistry and pH-profile of urine were examined for sixty four stone formers using powder X-ray diffraction, spectrophotometric and potentiometric techniques. The analysis indicated that 44 % of calculi were composed of pure calcium oxalate monohydrate, whereas other 56 % contained both monohydrate and dihydrate or usually their mixtures with hydroxyl apatite. Hypocitraturia, hypercalciuria and hyperuricosuria were identified as the most frequent disorders. Patients with pure calcium oxalate stones and calcium oxalate mixed with apatite revealed different patterns including age, acid-base balance of urine, calcium, citrate excretion etc.Conclusions: Our results demonstrate that most patients simultaneously reveal several risk factors. The special attention should be paid to normalize the daily citrate, calcium and urate excretion. High risk patients, such as postmenopausal females or stone formers with a high apatite content require a specific metabolic evaluation towards in highlighting abnormalities associated with stone formation.

Type III Bartter-like syndrome in an infant boy with Gitelman syndrome and autosomal dominant familial neurohypophyseal diabetes insipidus.

PubMed

Brugnara, Milena; Gaudino, Rossella; Tedeschi, Silvana; Syrèn, Marie-Louise; Perrotta, Silverio; Maines, Evelina; Zaffanello, Marco

2014-09-01

We report the case of an infant boy with polyuria and a familial history of central diabetes insipidus. Laboratory blood tests disclosed hypokalemia, metabolic alkalosis, hyperreninemia, and hyperaldosteronism. Plasma magnesium concentration was slightly low. Urine analysis showed hypercalciuria, hyposthenuria, and high excretion of potassium. Such findings oriented toward type III Bartter syndrome (BSIII). Direct sequencing of the CLCNKB gene revealed no disease-causing mutations. The water deprivation test was positive. Magnetic resonance imaging showed a lack of posterior pituitary hyperintensity. Finally, direct sequencing of the AVP-NPII gene showed a point mutation (c.1884G>A) in a heterozygous state, confirming an autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI). This condition did not explain the patient's phenotype; thus, we investigated for Gitelman syndrome (GS). A direct sequencing of the SLC12A3 gene showed c.269A>C and c.1205C>A new mutations. In conclusion, the patient had a genetic combination of GS and adFNDI with a BSIII-like phenotype.

Antenatal Bartter Syndrome: A Review

PubMed Central

Bhat, Y. Ramesh; Vinayaka, G.; Sreelakshmi, K.

2012-01-01

Antenatal Bartter syndrome (ABS) is a rare autosomal recessive renal tubular disorder. The defective chloride transport in the loop of Henle leads to fetal polyuria resulting in severe hydramnios and premature delivery. Early onset, unexplained maternal polyhydramnios often challenges the treating obstetrician. Increasing polyhydramnios without apparent fetal or placental abnormalities should lead to the suspicion of this entity. Biochemical analysis of amniotic fluid is suggested as elevated chloride level is usually diagnostic. Awareness, early recognition, maternal treatment with indomethacin, and amniocentesis allow the pregnancy to continue. Affected neonates are usually born premature, have postnatal polyuria, vomiting, failure to thrive, hypercalciuria, and subsequently nephrocalcinosis. Hypokalemia, metabolic alkalosis, secondary hyperaldosteronism and hyperreninaemia are other characteristic features. Volume depletion due to excessive salt and water loss on long term stimulates renin-angiotensin-aldosterone system resulting in juxtaglomerular hyperplasia. Clinical features and electrolyte abnormalities may also depend on the subtype of the syndrome. Prenatal diagnosis and timely indomethacin administration prevent electrolyte imbalance, restitute normal growth, and improve activity. In this paper, authors present classification, pathophysiology, clinical manifestations, laboratory findings, complications, and prognosis of ABS. PMID:22518185

[Quantitative mineralogical analyzes of kidney stones and diagnosing metabolic disorders in female patients with calcium oxalate urolithiasis].

PubMed

Kustov, A V; Moryganov, M A; Strel'nikov, A I; Zhuravleva, N I; Airapetyan, A O

2016-02-01

To conduct a complex examination of female patients with calcium oxalate urolithiasis to detect metabolic disorders, leading to stone formation. The study was carried out using complex physical and chemical methods, including quantitative X-ray phase analysis of urinary stones, pH measurement, volumetry, urine and blood spectrophotometry. Quantitative mineralogical composition of stones, daily urine pH profile, daily urinary excretion of ions of calcium, magnesium, oxalate, phosphate, citrate and uric acid were determined in 20 female patients with calcium oxalate stones. We have shown that most of the stones comprised calcium oxalate monohydrate or mixtures of calcium oxalate dihydrate and hydroxyapatite. Among the identified abnormalities, the most frequent were hypocitraturia and hypercalciuria - 90 and 45%, respectively. Our findings revealed that the daily secretion of citrate and oxalate in patients older than 50 years was significantly lower than in younger patients. In conclusion, daily urinary citrate excretion should be measured in female patients with calcium oxalate stones. This is necessary both to determine the causes of stone formation, and to monitor the effectiveness of citrate therapy.

Inherited renal tubulopathies associated with metabolic alkalosis: effects on blood pressure.

PubMed

Ariceta, Gema; Rodríguez-Soriano, Juan

2006-11-01

Inherited tubular disorders associated with metabolic alkalosis are caused by several gene mutations encoding different tubular transporters responsible for NaCl renal handling. Body volume and renin-angiotensin-aldosterone system status are determined by NaCl reabsorption in the distal nephron. Two common hallmarks in affected individuals: hypokalemia and normal / high blood pressure, support the differential diagnosis. Bartter's syndrome, characterized by hypokalemia and normal blood pressure, is a heterogenic disease caused by the loss of function of SLC12A1 (type 1), KCNJ1 (type 2), CLCNKB (type 3), or BSND genes (type 4). As a result, patients present with renal salt wasting and hypercalciuria. Gitelman's syndrome is caused by the loss of funcion of the SLC12A3 gene and may resemble Bartter's syndrome, though is associated with the very low urinary calcium. Liddle's syndrome, also with similar phenotype but with hypertension, is produced by the gain of function of the SNCC1B or SNCC1G genes, and must be distinguished from other entities of inherited hypertension such as Apparently Mineralocorticoid Excess, of glucocorticoid remediable hypertension.

Familial mixed nephrocalcinosis as a cause of chronic kidney failure: two case reports.

PubMed

de Arruda, Pedro Francisco Ferraz; Gatti, Márcio; de Arruda, José Germano Ferraz; Fácio, Fernando Nestor; Spessoto, Luis Cesar Fava; de Arruda, Laísa Ferraz; de Godoy, José Maria Pereira; Godoy, Moacir Fernandes

2014-10-27

Nephrocalcinosis consists of the deposition of calcium salts in the renal parenchyma and is considered the mixed form when it involves the renal cortex and medulla. The main etiological agents of this condition are primary hyperparathyroidism, renal tubular acidosis, medullary sponge kidney, hyperoxaluria and taking certain drugs. These factors can lead to hypercalcemia and/or hypercalciuria, which can give rise to nephrocalcinosis. Patient 1 was a 48-year-old Caucasian woman with a history of bilateral nephrocalcinosis causing chronic kidney failure. Imaging examinations (X-ray, ultrasound and computed tomography of the abdomen) revealed extensive calcium deposits in the renal parenchyma, indicating nephrocalcinosis as the causal factor of the disease. Patient 2 is the 45-year-old brother of patient 1. He exhibited an advanced stage of chronic kidney failure. As nephrocalcinosis is considered to have a genetic component, a family investigation revealed this condition in patient 2. Nephrocalcinosis may be detected incidentally through diagnostic imaging studies. Whenever possible, treatment should include the base disease that caused the appearance of the calcification, as the precise etiological determination is extremely important.

Bartter's syndrome with type 2 diabetes mellitus.

PubMed

See, Ting-Ting; Lee, Siu-Pak

2009-02-01

We report a rare case of Bartter's syndrome in a 35-year-old woman with type 2 diabetes mellitus. The patient presented with leg weakness, fatigue, polyuria and polydipsia. Hypokalemia, metabolic alkalosis, and high renin and aldosterone concentrations were present, but the patient was normotensive. Gitelman's syndrome was excluded because of the presence of hypercalciuria, secondary hyperparathyroidism and bilateral nephrocalcinosis. The patients condition improved upon administration of a prostaglandin synthetase inhibitor (acemetacin), oral potassium chloride and potassium-sparing diuretics. Five months later, the patient discontinued acemetacin because of epigastric discomfort; at the same time, severe hypokalemia and hyperglycemia developed. Glucagon stimulation and water deprivation tests were performed. Type 2 diabetes mellitus with nephrogenic diabetes insipidus was diagnosed. To avoid further gastrointestinal complications, the patient was treated with celecoxib, a selective cyclooxygenase 2 inhibitor. This case serves as a reminder that Bartter's syndrome is associated with various metabolic derangements including nephrogenic diabetes insipidus, nephrocalcinosis and diabetes mellitus. When treating Bartter's syndrome, it is also prudent to remember that the long-term use of nonsteroidal anti-inflammatory drugs and potassium-sparing diuretics may result in serious adverse reactions.

Four siblings with distal renal tubular acidosis and nephrocalcinosis, neurobehavioral impairment, short stature, and distinctive facial appearance: a possible new autosomal recessive syndrome.

PubMed

Faqeih, Eissa; Al-Akash, Samhar I; Sakati, Nadia; Teebi, Prof Ahmad S

2007-09-01

We report on four siblings (three males, one female) born to first cousin Arab parents with the constellation of distal renal tubular acidosis (RTA), small kidneys, nephrocalcinosis, neurobehavioral impairment, short stature, and distinctive facial features. They presented with early developmental delay with subsequent severe mental, behavioral and social impairment and autistic-like features. Their facial features are unique with prominent cheeks, well-defined philtrum, large bulbous nose, V-shaped upper lip border, full lower lip, open mouth with protruded tongue, and pits on the ear lobule. All had proteinuria, hypercalciuria, hypercalcemia, and normal anion-gap metabolic acidosis. Renal ultrasound examinations revealed small kidneys, with varying degrees of hyperechogenicity and nephrocalcinosis. Additional findings included dilated ventricles and cerebral demyelination on brain imaging studies. Other than distal RTA, common causes of nephrocalcinosis were excluded. The constellation of features in this family currently likely represents a possibly new autosomal recessive syndrome providing further evidence of heterogeneity of nephrocalcinosis syndromes. Copyright 2007 Wiley-Liss, Inc.

Nephrolithiasis in identical twins: the impact of nature vs nurture.

PubMed

Haleblian, George E; Cantor, David A; Sur, Roger L; Assimos, Dean G; Preminger, Glenn M

2007-09-01

To assess possible underlying metabolic abnormalities in three sets of monozygotic twins, to evaluate the interplay among the factors of kidney stone formation, a complex multifactorial process influenced by environmental, genetic and anatomical factors. Three sets of identical twins with either cystine or calcium oxalate stones were identified. Demographic data, medical histories and the results of 24-h urine testing, with samples collected on self-selected diets, were reviewed and analysed. The cystinuric twins had very similar cystine excretion rates, while stone activity was significantly more pronounced in one. Metabolic abnormalities were concordant in one set of twins with calcium oxalate stones, both being hypercalciuric and hyperuricosuric. However, metabolic abnormalities were discordant in the other pair, one twin with hypercalciuria and the other with hypocitraturia. Two of the three pairs had low urinary volume. These results support previous observations that environmental, genetic and potentially, anatomical factors play roles in kidney-stone formation. Additional controlled studies of monozygotic stone-forming twins might help to define the interplay between environmental and genetic factors, and allow the identification of susceptibility genes involved in stone generation.

A multiregional Italian cohort of 24-hour urine metabolic evaluation in renal stone formers.

PubMed

Esperto, Francesco; Marangella, Martino; Trinchieri, Alberto; Petrarulo, Michele; Miano, Roberto

2018-02-01

Nephrolithiasis is a common condition with several studies documenting an increased prevalence over the past four decades. EAU and AUA guidelines recommend 24-hour urine metabolic evaluation in high-risk stone formers. Aim of this study is to retrospectively evaluate the first three years of experience with LithoTest® (Biohealth Italia Srl, Turin, Italy) through the analysis of demographic, clinical and biochemical data collected from a large cohort of patients with kidney stones. We retrospectively analyzed data from the LithoCenter database, including data from outpatient consultations, between January 2007 and December 2009 from all over Italy. LithoTest® was performed through a 24-hour urine collection and included measurements of urine volume and pH, 24-hour excretion of creatinine as well as main cations and anions, including calcium, magnesium sodium potassium, ammonium, uric acid, oxalate, citrate, phosphate, inorganic sulphate and chloride. Urine state of saturation for calcium oxalate (βCaOx), calcium hydrogen phosphate or brushite (βbsh) and uric acid (βUA) were also calculated by means of the computer program LithoRisk. Brand's test for cystinuria was also carried out. Statistical analysis was performed using the S-PSS software v. 22.0. The number of patients with data available for analysis was 435, of whom 236 were male (54%) and 199 female (46%). Complete 24-hour urine measurements were available for all 435 patients. Compared to men, women had significantly lower values for creatinine, urate, oxalate, phosphate, sodium, potassium, magnesium and chloride excretion, whereas 24-hour pH and citrate excretion were higher. No significant differences were found for the other examined variables. βCaOx and βUA were significantly higher in men than women, whereas no significant difference was found for βbsh. There was a direct relationship between calcium and sodium urine excretion. Excessive sodium excretion was recorded in 191 patients (44%) and low urine volumes in 201 (46.2%). Hyperoxaluria was observed in 118 patients (27.3%), hypercalciuria in 115 (26.6%), hyperuricosuria in 153 (35.4%), hypomagnesuria in 96 (22.2%), and hypocitraturia in 134 patients (31%). Hyperexcretion of sodium, hypocitraturia and hyperoxaluria were most frequent in males. βCaOx was significantly higher in the setting of hypercalciuria, hypocitraturia, hyperoxaluria and urine pH below 5.5. Our findings in a large cohort of high-risk stone-forming patients show significant differences in urinary metabolic profiles between men and women. Carrying on the collection and analysis of data by LithoTest® from 2009 to 2015 and matching urinary and dietary data could eventually improve our understanding on the metabolic profile of stone-formers in Italy.

Claudin-16 and claudin-19 interact and form a cation-selective tight junction complex

PubMed Central

Hou, Jianghui; Renigunta, Aparna; Konrad, Martin; Gomes, Antonio S.; Schneeberger, Eveline E.; Paul, David L.; Waldegger, Siegfried; Goodenough, Daniel A.

2008-01-01

Tight junctions (TJs) play a key role in mediating paracellular ion reabsorption in the kidney. Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is an inherited disorder caused by mutations in the genes encoding the TJ proteins claudin-16 (CLDN16) and CLDN19; however, the mechanisms underlying the roles of these claudins in mediating paracellular ion reabsorption in the kidney are not understood. Here we showed that in pig kidney epithelial cells, CLDN19 functioned as a Cl– blocker, whereas CLDN16 functioned as a Na+ channel. Mutant forms of CLDN19 that are associated with FHHNC were unable to block Cl– permeation. Coexpression of CLDN16 and CLDN19 generated cation selectivity of the TJ in a synergistic manner, and CLDN16 and CLDN19 were observed to interact using several criteria. In addition, disruption of this interaction by introduction of FHHNC-causing mutant forms of either CLDN16 or CLDN19 abolished their synergistic effect. Our data show that CLDN16 interacts with CLDN19 and that their association confers a TJ with cation selectivity, suggesting a mechanism for the role of mutant forms of CLDN16 and CLDN19 in the development of FHHNC. PMID:18188451

Antiurolithiatic and antioxidant efficacy of Musa paradisiaca pseudostem on ethylene glycol-induced nephrolithiasis in rat

PubMed Central

Panigrahi, Padma Nibash; Dey, Sahadeb; Sahoo, Monalisa; Dan, Ananya

2017-01-01

Objective: Musa paradisiaca has been used in the treatment of urolithiasis by the rural people in South India. Therefore, we plan to evaluate its efficacy and possible mechanism of antiurolithiatic effect to rationalize its medicinal use. Materials and Methods: Urolithiasis was induced in hyperoxaluric rat model by giving 0.75% ethylene glycol (EG) for 28 days along with 1% ammonium chloride (AC) for the first 14 days. Antiurolithiatic effect of aqueous-ethanol extract of M. paradisiaca pseudostem (MUSA) was evaluated based on urine and serum biochemistry, microscopy of urine, oxidative/nitrosative indices, kidney calcium content, and histopathology. Results: Administration of EG and AC resulted in increased crystalluria and oxaluria, hypercalciuria, polyuria, crystal deposition in urine, raised serum urea, and creatinine as well as nitric oxide concentration and erythrocytic lipid peroxidation in lithiatic group. However, MUSA treatment significantly restored the impairment in above kidney function test as that of standard treatment, cystone in a dose-dependent manner. Conclusions: The present findings demonstrate the efficacy of MUSA in EG-induced urolithiasis, which might be mediated through inhibiting various pathways involved in renal calcium oxalate formation, antioxidant effect, and potential to inhibit biochemical markers of renal impairment. PMID:28458427

Ecological study of dietary and smoking links to lymphoma

NASA Technical Reports Server (NTRS)

Grant, W. B.

2000-01-01

The ecological approach is used to investigate dietary and smoking links to lymphoma. International mortality rate data for 1986 and 1994 by gender and age group are compared with national dietary supply values of various food components for up to 10 years prior to the mortality data as well as per capita cigarette consumption rates 5 and 15 years earlier. The non-fat portion of milk, 3-9 years prior to the 1986 mortality data and 4 years prior to the 1994 data, was found to have the highest association with lymphoma, with r as high as 0.89. The results imply that 70 percent of lymphoma mortality may be related to this dietary component. Cigarette smoking in 1980 was found to have a weaker association with 1994 lymphoma mortality rates, being most important for younger men and statistically insignificant for younger women. The non-fat milk result is consistent with both case-control studies and a Norwegian prospective study, and with the often-observed finding that abnormal calcium metabolism, hypercalciuria, and dysregulated calcitriol production are common in normocalcemic patients with non-Hodgkin's lymphoma (NHL). It is hypothesized that excess dietary calcium from milk is a significant risk factor for lymphoma.

Antiurolithiatic and antioxidant efficacy of Musa paradisiaca pseudostem on ethylene glycol-induced nephrolithiasis in rat.

PubMed

Panigrahi, Padma Nibash; Dey, Sahadeb; Sahoo, Monalisa; Dan, Ananya

2017-01-01

Musa paradisiaca has been used in the treatment of urolithiasis by the rural people in South India. Therefore, we plan to evaluate its efficacy and possible mechanism of antiurolithiatic effect to rationalize its medicinal use. Urolithiasis was induced in hyperoxaluric rat model by giving 0.75% ethylene glycol (EG) for 28 days along with 1% ammonium chloride (AC) for the first 14 days. Antiurolithiatic effect of aqueous-ethanol extract of M. paradisiaca pseudostem (MUSA) was evaluated based on urine and serum biochemistry, microscopy of urine, oxidative/nitrosative indices, kidney calcium content, and histopathology. Administration of EG and AC resulted in increased crystalluria and oxaluria, hypercalciuria, polyuria, crystal deposition in urine, raised serum urea, and creatinine as well as nitric oxide concentration and erythrocytic lipid peroxidation in lithiatic group. However, MUSA treatment significantly restored the impairment in above kidney function test as that of standard treatment, cystone in a dose-dependent manner. The present findings demonstrate the efficacy of MUSA in EG-induced urolithiasis, which might be mediated through inhibiting various pathways involved in renal calcium oxalate formation, antioxidant effect, and potential to inhibit biochemical markers of renal impairment.

Cystinosis Presenting with Findings of Bartter Syndrome

PubMed Central

Özkan, Behzat; Çayır, Atilla; Koşan, Celalettin; Alp, Handan

2011-01-01

A five-year-old boy was referred to our pediatric clinic for evaluation of failure to thrive, headache, intermittent high fever, restlessness, polyuria, and polydipsia. His weight and height measurements were under the 3rd percentile. Clinical findings consisted of frontal bossing, carious teeth, O-bain deformity of the lower extremities, and moderate dehydration. The presence of metabolic alkalosis, hypokalemia, hypochloremia, and high renin and aldosterone levels were suggestive of Bartter syndrome and a treatment regimen for Bartter syndrome was started. At follow-up, the polyuria and hyponatremia were found to persist. A reassessment of the patient revealed findings consistent with proximal renal tubular acidosis such as metabolic acidosis with a high urinary pH, proteinuria, aminoaciduria with phosphaturia and hypercalciuria. Based on the presence of parental consanguinity as well as polyuria, proteinuria, low tubular reabsorption of phosphorus, generalized aminoaciduria, light yellow skin and hair color, the probable diagnosis of cystinosis was established and was confirmed by slit-lamp examination of the cornea showing cystine crystal deposition. Our case is a good example demonstrating that development of metabolic alkalosis does not exclude cystinosis and that all findings of the patient should be thoroughly evaluated. Conflict of interest:None declared. PMID:21750641

A patient with Dent disease and features of Bartter syndrome caused by a novel mutation of CLCN5.

PubMed

Okamoto, Takayuki; Tajima, Toshihiro; Hirayama, Tomoya; Sasaki, Satoshi

2012-02-01

Dent disease is an X-linked tubulopathy mainly caused by inactivating mutations of CLCN5. Features of Bartter syndrome such as hypokalemic metabolic alkalosis are rarely observed in patients with Dent disease. We report a Japanese male patient with Dent disease who also manifested features of Bartter syndrome. At the age of 3 years, he was diagnosed with Dent disease based on low molecular weight proteinuria and hypercalciuria. One year later, he was found to have features of Bartter syndrome, i.e., hypokalemia and metabolic alkalosis, and high levels of plasma renin activity and aldosterone with a normal blood pressure. Despite medical interventions, he developed chronic kidney disease stage 3 at the age of 21 years. To investigate the molecular basis of his disease, CLCN5, KCNJ1, SLC12A1, and CLCkb were analyzed and a novel mutation (Y567X) in CLCN5 was identified. Hypokalemic metabolic alkalosis is a rare manifestation in Dent disease. It is speculated that Dent patients with features of Bartter syndrome are susceptible to progression to renal failure. To study this hypothesis, additional observations and long-term follow-up of such patients are necessary.

Cystinosis presenting with findings of Bartter syndrome.

PubMed

Özkan, Behzat; Çayır, Atilla; Koşan, Celalettin; Alp, Handan

2011-01-01

A five-year-old boy was referred to our pediatric clinic for evaluation of failure to thrive, headache, intermittent high fever, restlessness, polyuria, and polydipsia. His weight and height measurements were under the 3rd percentile. Clinical findings consisted of frontal bossing, carious teeth, O-bain deformity of the lower extremities, and moderate dehydration. The presence of metabolic alkalosis, hypokalemia, hypochloremia, and high renin and aldosterone levels were suggestive of Bartter syndrome and a treatment regimen for Bartter syndrome was started. At follow-up, the polyuria and hyponatremia were found to persist. A reassessment of the patient revealed findings consistent with proximal renal tubular acidosis such as metabolic acidosis with a high urinary pH, proteinuria, aminoaciduria with phosphaturia and hypercalciuria. Based on the presence of parental consanguinity as well as polyuria, proteinuria, low tubular reabsorption of phosphorus, generalized aminoaciduria, light yellow skin and hair color, the probable diagnosis of cystinosis was established and was confirmed by slit-lamp examination of the cornea showing cystine crystal deposition. Our case is a good example demonstrating that development of metabolic alkalosis does not exclude cystinosis and that all findings of the patient should be thoroughly evaluated. ©Journal of Clinical Research in Pediatric Endocrinology, Published by Galenos Publishing.

A Randomized controlled trial on safety and efficacy of single intramuscular versus staggered oral dose of 600 000IU Vitamin D in treatment of nutritional rickets.

PubMed

Mondal, Krishanu; Seth, Anju; Marwaha, Raman K; Dhanwal, Dinesh; Aneja, Satinder; Singh, Ritu; Sonkar, Pitambar

2014-06-01

Comparison of efficacy and safety of two different regimens of vitamin D-600 000 IU as a single intramuscular dose, and 60 000IU orally once a week for 10 weeks-in treatment of nutritional rickets. Children with nutritional rickets (age: 0.5-5 years, n = 61) were randomized to receive either 60 000IU vitamin D orally once a week for 10 weeks or 600 000IU single intramuscular injection. Serum calcium, phosphate, alkaline phosphatase, urinary calcium/creatinine ratio, serum 25 hydroxy vitamin D and radiological score were compared at 12-week follow-up. No difference was found in efficacy of the two regimens on comparing biochemical and radiological parameters. Serum 25 hydroxy vitamin D >100 ng/ml was found in two children in the oral group and one child in the intramuscular group. No child developed hypercalcemia or hypercalciuria after starting treatment. Staggered oral and one-time intramuscular administrations of 600 000IU vitamin D are equally effective and safe in treatment of nutritional rickets. © The Author [2014]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Molecular bases of diseases characterized by hypophosphatemia and phosphaturia: new understanding.

PubMed

Ozono, Keiichi; Michigami, Toshimi; Namba, Noriyuki; Nakajima, Shigeo; Yamamoto, Takehisa

2006-01-01

Serum phosphate levels are regulated in both calcium-dependent and -independent fashions. Active vitamin D increases while PTH decreases serum phosphate levels in association with the elevation of serum calcium. On the other hand, a calcium-independent phosphaturic factor, historically called phosphatonin is believed to exert a physiological function based on findings in hereditary and tumor-induced diseases characterized by hypophosphatemia with normocalcemia. Among them, autosomal dominant hypophosphatemic rickets (ADHR) has contributed greatly to its elucidation because the gene responsible for ADHR encodes fibroblast growth factor 23 (FGF23) that has been found to have a phosphaturic effect. In addition, FGF23 has been proved to be involved in most cases of oncogenic osteomalacia and X-linked hypophosphatemic rickets that are also characterized by hypophosphatemia and normocalcemia. Moreover, familial tumoral calcinosis, which represents the metabolic mirror image of hypophosphatemic conditions, is caused by a loss-of-function mutation in the FGF23 gene in some patients. Very recently, hereditary hypophosphatemic rickets with hypercalciuria has been found to be caused by mutations in the SLC34A1 gene which encodes a type of sodium phosphate cotransporter. These findings may provide new strategies for treating patients with abnormal phosphate metabolism.

Primary hyperparathyroidism: recent advances.

PubMed

Walker, Marcella D; Bilezikian, John P

2018-07-01

The purpose of this review is to describe recent advances and changes in the evaluation and management of primary hyperparathyroidism (PHPT). Although it has long been recognized that asymptomatic PHPT is associated with bone loss, particularly at cortical skeletal sites when evaluated with dual-energy X-ray absorptiometry, new imaging techniques suggest that trabecular skeletal deterioration as well as clinically silent vertebral fractures and nephrolithiasis are common. Nonclassical targets of asymptomatic PHPT as well as the effect of vitamin D deficiency and treatment upon PHPT presentation have been the subject of recent intense investigation. Randomized clinical trials are now available regarding the effect of parathyroidectomy (PTX) upon both classical and nonclassical target organs. They have confirmed results from observational studies with regard to the skeletal benefits of PTX but have not consistently shown improvements in nonclassical symptoms. These findings have led to recommendations for more extensive renal and skeletal evaluation and broader criteria for PTX in PHPT. In addition to dual-energy X-ray absorptiometry, vertebral and renal imaging is recommended. When available, trabecular imaging techniques may be helpful. PTX criteria now include subclinical kidney stones, vertebral fractures and hypercalciuria, in addition to those based on age, serum calcium, bone densitometry and renal function.

[Etiological orientation from the analysis morphological and constitutional of urinary stones in Conakry].

PubMed

Kaba, M L; Bah, O R; Baldé, N M; Bigot, J C; Bah, A O; Diakité, M; Baldé, I; Panzo, D A; Touré, Y I; Diallo, M B; Carré, J L

2007-01-01

The epidemiological profile of urinary stones varies from region of the world to another according to food habit and certain enviromental factors. The aim of our study was to establish an etiological approach of the urinary lithiasis collected in Conakry by morphological and constitutional analysis. It was a prospective study from january 1 rst 2003 to january 1 rst 2004 concerning all the stones collected. They were analysed by binocular magnifying glass and infra red spectrophotometry of Fourier. During the period, 18 patients were observed (14 male, 4 femele) of 27.4 +/- 4 years old (from 2 to 69) living mainly in urban environment. From these patients 28 stones were collected; 12 spontaneously and 16 surgicaly. Their composition were whewellite (36%), struvite (29%), carbapatite (14%), urates (14%) and weddellite (7%). In Conakry stones come mainly from hyperoxaluria and urinary tract infection; hypercalciuria is uncomon. The urinary calculations examined among patients show in the adult a prevalence of elements in favour of a hyperoxalurie and a notable context of urinary infections in particular in the child; the pure hypercalciurie remains negligible in Conakry, we plan to lead a thorough work to the national scales.

KIDNEY STONES: AN UPDATE ON CURRENT PHARMACOLOGICAL MANAGEMENT AND FUTURE DIRECTIONS

PubMed Central

Xu, Hongshi; Zisman, Anna L.; Coe, Fredric L.; Worcester, Elaine M.

2013-01-01

Introduction Kidney stones are a common problem worldwide with substantial morbidities and economic costs. Medical therapy reduces stone recurrence significantly. Much progress has been made in the last several decades in improving therapy of stone disease. Areas covered 1) effect of medical expulsive therapy on spontaneous stone passage, 2) pharmacotherapy in the prevention of stone recurrence, 3) future directions in the treatment of kidney stone disease. Expert Opinion fluid intake to promote urine volume of at least 2.5L each day is essential to prevent stone formation. Dietary recommendations should be adjusted based on individual metabolic abnormalities. Properly dosed thiazide treatment is the standard therapy for calcium stone formers with idiopathic hypercalciuria. Potassium alkali therapy is considered for hypocitraturia, but caution should be taken to prevent potential risk of calcium phosphate stone formation. For absorptive hyperoxaluria, low oxalate diet and increased dietary calcium intake are recommended. Pyridoxine has been shown effective in some cases of primary hyperoxaluria type I. Allopurinol is used in calcium oxalate stone formers with hyperuricosuria. Treatment of cystine stones remains challenging. Tiopronin can be used if urinary alkalinization and adequate fluid intake are insufficient. For struvite stones, complete surgical removal coupled with appropriate antibiotic therapy is necessary. PMID:23438422

Clinical, demographic, and laboratory characteristics of children with nephrolithiasis.

PubMed

Sas, David J; Becton, Lauren J; Tutman, Jeffrey; Lindsay, Laura A; Wahlquist, Amy H

2016-06-01

While the incidence of pediatric kidney stones appears to be increasing, little is known about the demographic, clinical, laboratory, imaging, and management variables in this patient population. We sought to describe various characteristics of our stone-forming pediatric population. To that end, we retrospectively reviewed the charts of pediatric patients with nephrolithiasis confirmed by imaging. Data were collected on multiple variables from each patient and analyzed for trends. For body mass index (BMI) controls, data from the general pediatrics population similar to our nephrolithiasis population were used. Data on 155 pediatric nephrolithiasis patients were analyzed. Of the 54 calculi available for analysis, 98 % were calcium based. Low urine volume, elevated supersaturation of calcium phosphate, elevated supersaturation of calcium oxalate, and hypercalciuria were the most commonly identified abnormalities on analysis of 24-h urine collections. Our stone-forming population did not have a higher BMI than our general pediatrics population, making it unlikely that obesity is a risk factor for nephrolithiasis in children. More girls presented with their first stone during adolescence, suggesting a role for reproductive hormones contributing to stone risk, while boys tended to present more commonly at a younger age, though this did not reach statistical significance. These intriguing findings warrant further investigation.

The risk of renal stone formation during and after long duration space flight

NASA Technical Reports Server (NTRS)

Whitson, P. A.; Pietrzyk, R. A.; Morukov, B. V.; Sams, C. F.

2001-01-01

BACKGROUND: The formation of a renal stone during space flight may have serious negative effects on the health of the crewmember and the success of the mission. Urinary biochemical factors and the influence of dietary factors associated with renal stone development were assessed during long duration Mir Space Station missions. METHODS: Twenty-four-hour urine samples were collected prior to, during and following long duration space flight. The relative urinary supersaturation of calcium oxalate, calcium phosphate (brushite), sodium urate, struvite and uric acid were determined. RESULTS: Changes in the urinary biochemistry of crewmembers during long duration spaceflight demonstrated increases in the supersaturation of the stone-forming salts. In-flight hypercalciuria was evident in a number of individual crewmembers and 24-hour dietary fluid intake and urine volume were significantly lower. During flight, there was a significant increase in brushite supersaturation. CONCLUSIONS: These data suggest acute effects of space flight and postflight changes in the urinary biochemistry favoring increased crystallization in the urine. The effects of dietary intake, especially fluid intake, may have a significant impact on the potential for renal stone formation. Efforts are now underway to assess the efficacy of a countermeasure to mitigate the increased risk. Copyright 2001 S. Karger AG, Basel.

Evidence for net renal tubule oxalate secretion in patients with calcium kidney stones

PubMed Central

Zisman, Anna L.; Asplin, John R.; Worcester, Elaine M.; Coe, Fredric L.

2011-01-01

Little is known about the renal handling of oxalate in patients with idiopathic hypercalciuria (IH). To explore the role of tubular oxalate handling in IH and to evaluate whether differences exist between IH and normal controls, we studied 19 IH subjects, 8 normal subjects, and 2 bariatric stone formers (BSF) during a 1-day General Clinical Research Center protocol utilizing a low-oxalate diet. Urine and blood samples were collected at 30- to 60-min intervals while subjects were fasting and after they ate three meals providing known amounts of calcium, phosphorus, sodium, protein, oxalate, and calories. Plasma oxalate concentrations and oxalate-filtered loads were similar between patients (includes IH and BSF) and controls in both the fasting and fed states. Urinary oxalate excretion was significantly higher in patients vs. controls regardless of feeding state. Fractional excretion of oxalate (FEOx) was >1, suggesting tubular secretion of oxalate, in 6 of 19 IH and both BSF, compared with none of the controls (P < 0.00001). Adjusted for water extraction along the nephron, urine oxalate rose more rapidly among patients than normal subjects with increases in plasma oxalate. Our findings identify tubular secretion of oxalate as a key mediator of hyperoxaluria in calcium stone formers, potentially as a means of maintaining plasma oxalate in a tight range. PMID:21123489

Metabolic factors associated with urinary calculi in children.

PubMed

Naseri, Mitra; Varasteh, Abdol Reza; Alamdaran, Seied Ali

2010-01-01

We aimed to identify metabolic and anatomical abnormalities present in children with urinary calculi. Metabolic evaluation was done in 142 pediatric calculus formers. Evaluation included serum biochemistry; measurement of daily excretion of urinary calcium, uric acid, oxalate, citrate, and magnesium (in older children); and measurement of calcium, uric acid, oxalate, and creatinine in random urine samples in nontoilet-trained patients. Urinary tests for cystinuria were also performed. All of the patients underwent renal ultrasonography. Sixty-one patients (42.7%) had metabolic abnormalities. Anatomical abnormalities were found in 12 patients (8.4%). Three children (2.1%) had infectious calculi, and 3(2.1%) had a combination of metabolic and anatomic abnormalities. In 66 children (46.2 %) we did not find any reasons for calculus formation (idiopathic). Urinalysis revealed hypercalciuria in 25 (17.6%), hyperuricosuria in 23 (16.1%), hyperoxaluria in 17 (11.9%), cystinuria in 9 (6.3%), hypocitraturia in 3 (2.1%), and low urinary magnesium level in 1 (0.7%) patients. Sixteen patients (11.2%) had mixed metabolic abnormalities. Metabolic abnormalities are common in pediatric patients with urinary calculi. In our study, calcium and uric acid abnormalities were the most common, and vesicoureteral reflux seemed to be the most common urological abnormality which led to urinary stasis and calculus formation.

Novel Mutation in the CASR Gene (p.Leu123Ser) in a Case of Autosomal Dominant Hypocalcemia

PubMed Central

Regala, Joana; Cavaco, Branca; Domingues, Rita; Limbert, Catarina; Lopes, Lurdes

2015-01-01

Autosomal dominant hypocalcemia, caused by activating mutations of the calcium-sensing receptor (CASR) gene, is characterized by hypocalcemia with an inappropriately low concentration of parathyroid hormone (PTH). In this report, we describe the identification of a novel missense mutation in the CASR gene, in a boy with autosomal dominant hypocalcemia. Polymerase chain reaction (PCR)–single strand and DNA sequencing revealed a heterozygous mutation in CASR gene that causes a leucine substitution for serine at codon 123 (p.Leu123Ser). This mutation was absent in DNA from 50 control patients. In silico studies suggest that the identified variant was likely pathogenic. Sequencing analysis in the mother suggested mosaicism for the same variant, and she was clinically and biochemically unaffected. Clinical manifestations of the index case started with seizures at 14 months of age; cognitive impairment and several neuropsychological disabilities were noted during childhood. Extrapyramidal signs and basal ganglia calcification developed later, namely, hand tremor and rigidity at the age of 7 and 18 years, respectively. Laboratory analysis revealed hypocalcemia, hyperphosphatemia, and low-serum PTH with hypomagnesemia and mild hypercalciuria. After 2 years of treatment with calcium supplements and calcitriol, some brief periods of clinical improvement were reported; as well as an absence of nephrocalcinosis. PMID:27617113

A novel CLCN5 mutation in a boy with Bartter-like syndrome and partial growth hormone deficiency.

PubMed

Bogdanović, Radovan; Draaken, Markus; Toromanović, Alma; Dordević, Maja; Stajić, Natasa; Ludwig, Michael

2010-11-01

Dent disease is an X-linked recessive disorder affecting the proximal tubule and is characterized by low-molecular-weight proteinuria (LMWP), hypercalciuria, nephrocalcinosis/nephrolithiasis with a variable number of features of Fanconi syndrome. It is most often associated with mutations in CLCN5, which encodes the endosomal electrogenic chloride/proton exchanger ClC-5. Renal acidification abnormalities are only rarely seen in Dent disease, whereas the hypokalemic metabolic alkalosis associated with hyperreninemic hyperaldosteronism (Bartter-like syndrome) has been reported in only one patient so far. We report on a 5-year-old boy with Dent disease caused by mutation in CLCN5 gene, c.1073G>A, who presented with hypokalemic metabolic alkalosis and hyperreninemic hyperaldosteronism persisting over the entire follow-up. No mutations were found in NKCC2, ROMK, NCCT, or ClC-Kb genes. In addition, the patient exhibited growth failure associated with partial growth hormone (GH) deficiency. Coexistence of Bartter-like syndrome features with LMWP should prompt a clinician to search for Dent disease. The Bartter syndrome phenotype seen in Dent disease patients may represent a distinct form of Bartter syndrome, the exact mechanism of which has yet to be fully elucidated. Growth delay that persists in spite of appropriate therapy should raise suspicion of other causes, such as GH deficiency.

Effect of fruit on net acid and urinary calcium excretion in an acute feeding trial of women.

PubMed

Bell, Janet Amy; Whiting, Susan Joyce

2004-05-01

Consumption of fruits and vegetables has been implicated in lowering net acid excretion (NAE), but few studies have directly examined NAE and urinary calcium effects. Further, there is no evidence that only fresh fruits and vegetables must be consumed for a beneficial effect on bone. A crossover, acute-load study was designed to investigate whether processed fruit was as effective as fresh fruit in reducing NAE and protein-induced hypercalciuria. Fifteen women completed three dietary treatments on three different mornings. A fasting urine sample was collected before consuming one of the following three isocaloric high-protein treatments: control, fresh apples, and processed applesauce. The serving size for the applesauce treatment was 2.5 times that for fresh apples. Urine was collected at baseline (0 h) and at 1.5, 3.0, and 4.5 h. Compared with baseline, NAE increased after control treatment but decreased after fresh or processed apple treatment (P = 0.041). Calcium excretion increased with all treatments by 3 h; however, the increase was less for fresh apple and applesauce (P = 0.024). In an acute feeding model, fruit intake reduced NAE and urinary calcium excretion. Processed fruit appears to be effective, although a larger serving size was needed than with fresh fruit.

Stones, bones, and heredity.

PubMed

Milliner, Dawn S

2006-07-01

Genetic disorders of mineral metabolism cause urolithiasis, renal disease, and osteodystrophy. Most are rare, such that the full spectrum of clinical expression is difficult to appreciate. Diagnosis is further complicated by overlap of clinical features. Dent's disease and primary hyperoxaluria, inherited causes of calcium urolithiasis, are both associated with nephrocalcinosis and urolithiasis in early childhood and renal failure that can occur at any age but is seen more often in adulthood. Bone disease is an inconsistent feature of each. Dent's disease is caused by mutations of the CLCN-5 gene with impaired kidney-specific CLC-5 chloride channel expression in the proximal tubule, thick ascending limb of Henle, and the collecting ducts. Resulting hypercalciuria and proximal tubule dysfunction, including phosphate wasting, are primarily responsible for the clinical manifestations. Low-molecular-weight proteinuria is characteristic. Definitive diagnosis is made by DNA mutation analysis. Primary hyperoxaluria, type I, is due to mutations of the AGXT gene leading to deficient hepatic alanine-glyoxylate aminotransferase activity. Marked overproduction of oxalate by hepatic cells results in the hyperoxaluria responsible for clinical features. Definitive diagnosis is by liver biopsy with measurement of enzyme activity, with DNA mutation analysis used increasingly as mutations and their frequency are defined. These disorders of calcium urolithiasis illustrate the value of molecular medicine for diagnosis and the promise it provides for innovative and more effective future treatments.

MECHANISMS OF HUMAN KIDNEY STONE FORMATION

PubMed Central

Evan, Andrew P.; Worcester, Elaine M.; Coe, Fredric L.; Williams, James; Lingeman, James E.

2014-01-01

The precise mechanisms of kidney stone formation and growth are not completely known, even though human stone disease appears to be one of the oldest diseases known to medicine. With the advent of the new digital endoscope and detailed renal physiological studies performed on well phenotyped stone formers, substantial advances have been made in our knowledge of the pathogenesis of the most common type of stone former, the idiopathic calcium oxalate stone former (ICSF) as well as nine other stone forming groups. The observations from our group on human stone formers and those of others on model systems have suggested four entirely different pathways for kidney stone formation. Calcium oxalate stone growth over sites of Randall’s plaque appear to be the primary mode of stone formation for those patients with hypercalciuria. Overgrowths off the ends of Bellini duct plugs have been noted in most stone phenotypes, do they result in a clinical stone? Micro-lith formation does occur within the lumens of dilated inner medullary collecting ducts of cystinuric stone formers and appear to be confined to this space. Lastly, cystinuric stone formers also have numerous small, oval, smooth yellow appearing calyceal stones suggestive of formation in free solution. The scientific basis for each of these four modes of stone formation are reviewed and used to explore novel research opportunities. PMID:25108546

Dietary Sodium Effects on Bone Loss and Calcium Metabolism During Bed Rest

NASA Technical Reports Server (NTRS)

Smith, Scott M.; Arnaud, Sara B.; Abrams, Steven A.; Paloski, W. H. (Technical Monitor)

2000-01-01

The acceleration of age-related bone loss is one of the most detrimental effects of space flight. The ability to understand and counteract this loss will be critical for crew health and safety during and after long-duration missions. Studies in healthy ambulatory individuals have linked high salt (sodium) diets, hypercalciuria, and increased renal stone risk. Dietary salt may modulate bone loss through changes in calcium metabolism and the calcium endocrine system. The research proposed here will determine the role of dietary salt in the loss of bone during simulated space flight. Calcium metabolism will be determined through calcium kinetics studies, endocrine and biochemical measurements; and estimates of the mass, distribution and mechanical properties of bone, in subjects fed low (100 mmol sodium/day) or high (250 mmol sodium/day) levels of dietary salt during 28 days of headdown tilt bedrest. This research addresses the role of dietary salt in the loss of bone and calcium in space flight, and integrates the changes in calcium metabolism with those occurring in other physiologic systems. These data will be critical for both countermeasure development, and in determination of nutritional requirements for extended-duration space flight. The potential countermeasures resulting from this research will reduce health risks due to acceleration of age-related osteoporosis and increased risk of renal stone formation..

Evaluation and medical management of kidney stones in children.

PubMed

Tasian, Gregory E; Copelovitch, Lawrence

2014-11-01

We review the current literature on the diagnostic evaluation and dietary and pharmacological management of children with nephrolithiasis. We searched MEDLINE(®), Embase(®) and the Cochrane Library from their inceptions to March 2014 for published articles in English on kidney stones and therapy in children 0 to 18 years old. Based on review of the titles and abstracts, 110 of the 1,014 articles (11%) were potentially relevant to the diagnostic evaluation and medical management of nephrolithiasis in children. We summarized this literature and drew on studies performed in adult populations to augment areas in which no studies of sufficient quality have been performed in children, and to highlight areas in need of research. During the last 25 years the incidence of nephrolithiasis in children has increased by approximately 6% to 10% annually and is now 50 per 100,000 adolescents. Kidney stones that form during childhood have a similar composition to those that form in adulthood. Approximately 75% to 80% of stones are composed of predominantly calcium oxalate, 5% to 10% are predominantly calcium phosphate, 10% to 20% are struvite and 5% are pure uric acid. The recurrence rate of nephrolithiasis in patients with stones that form during childhood is poorly defined. Ultrasound should be used as the initial imaging study to evaluate children with suspected nephrolithiasis, with noncontrast computerized tomography reserved for those in whom ultrasound is nondiagnostic and the suspicion of nephrolithiasis remains high. Current treatment strategies for children with kidney stone disease are based largely on extrapolation of studies performed in adult stone formers and single institution cohort or case series studies of children. Tamsulosin likely increases the spontaneous passage of ureteral stones in children. Increased water intake and reduction of salt consumption should be recommended for all children with a history of kidney stones. Potassium citrate is a potentially effective medication for children with calcium oxalate stones and concomitant hypocitraturia, as well as children with uric acid stones. However, long-term compliance with therapy and the effect on decreasing stone recurrence in children are unknown. Based largely on efficacy in adult populations, thiazide diuretics should be considered in the treatment of children with calcium based stones and persistent hypercalciuria refractory to reductions in salt intake. The incidence of kidney stone disease in children is increasing, yet few randomized clinical trials or high quality observational studies have assessed whether dietary or pharmacological interventions decrease the recurrence of kidney stones in children. Collaborative efforts and randomized clinical trials are needed to determine the efficacy and effectiveness of alternative treatments for children with nephrolithiasis, particularly those with calcium oxalate stones and concomitant hypercalciuria and hypocitraturia. Additional areas in need of study are the optimal length of time for a trial of stone passage in children, the cost-effectiveness of medical expulsive therapy vs analgesics alone, and the size and location of stones for which medical expulsive therapy is most effective. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Predisposing factors for infantile urinary calculus in south-west of Iran.

PubMed

Alemzadeh-Ansari, Mohammad Hasan; Valavi, Ehsan; Ahmadzadeh, Ali

2014-01-01

Urinary calculi in infants are relatively infrequent, but their incidence has increased in the recent decades. The aim of this study was to investigate the clinical presentation, metabolic risk factors, and urinary tract abnormalities in infants suffering from kidney calculus. A total of 152 infants were admitted between 2009 and 2012 with ultrasonography-proven urolithiasis. A Foley catheter was fixed and 24-hour urine samples were analyzed for calcium, citrate, oxalate, uric acid, and magnesium. For detecting cystinuria, qualitative measurement of urinary cystine was done by nitroprusside test. Urinary tract structural abnormalities were also evaluated. The mean age at the diagnosis of kidney calculus was 5.46 months (range, 15 days to 12 months). The most common clinical findings were restlessness and urinary tract infection. A family history of calculi was found in 67.1% of the patients and 68.4% were born to consanguineous marriages. Metabolic abnormalities and urinary tract abnormalities were found in 96.1% and 15.1% of children, respectively. Urinary tract abnormalities were more common in girls. The most common metabolic risk factors were hypercalciuria (79.6%) and hypocitraturia (40.9%). Hyperoxaluria and hypomagnesuria were found in about 28% of patients, both of which were associated with bilateral urolithiasis. These findings show that urinary metabolic abnormalities are very common in infants with urolithiasis. Appropriate evaluation of urinary metabolic parameters can lead us to proper diagnosis and treatment.

Nutrition and renal stone disease in space

NASA Technical Reports Server (NTRS)

Zerwekh, Joseph E.

2002-01-01

There is a growing body of evidence from the National Aeronautics and Space Administration and the Russian space program showing that humans exposed to the microgravity environment of space have a greater risk for developing renal stones. Increased bone resorption and the attendant hypercalciuria and hyperphosphaturia contribute significantly to raising the urinary state of saturation with respect to the calcium salts, namely calcium oxalate and calcium phosphate. In addition, other environmental and dietary factors may adversely affect urine composition and increase stone formation risk during space flight. For example, reductions in urinary volume, pH, and citrate contribute to raising stone formation risk. In addition to raising the risk for calcium stone formation, this metabolic profile is conducive to the formation of uric acid stones. Although observations to date have suggested that there may actually be a reduced food intake during the early phase of flight, crew members on longer-duration flights may increase food intake and be at increased risk for stone formation. Taken together, these findings support the use of nutritional recommendations for crew members that would serve to reduce the stone-forming propensity of the urinary environment. Pharmacologic intervention should be directed at raising urinary volumes, diminishing bone losses, and preventing reductions in urinary pH and citrate. Success in reducing the risk for stone formation in astronauts would also be of potential major benefit to the estimated 20 million Americans with nephrolithiasis.

Late-onset Bartter syndrome type II.

PubMed

Gollasch, Benjamin; Anistan, Yoland-Marie; Canaan-Kühl, Sima; Gollasch, Maik

2017-10-01

Mutations in the ROMK1 potassium channel gene ( KCNJ1 ) cause antenatal/neonatal Bartter syndrome type II (aBS II), a renal disorder that begins in utero , accounting for the polyhydramnios and premature delivery that is typical in affected infants, who develop massive renal salt wasting, hypokalaemic metabolic alkalosis, secondary hyperreninaemic hyperaldosteronism, hypercalciuria and nephrocalcinosis. This BS type is believed to represent a disorder of the infancy, but not in adulthood. We herein describe a female patient with a remarkably late-onset and mild clinical manifestation of BS II with compound heterozygous KCNJ1 missense mutations, consisting of a novel c.197T > A (p.I66N) and a previously reported c.875G > A (p.R292Q) KCNJ1 mutation. We implemented and evaluated the performance of two different bioinformatics-based approaches of targeted massively parallel sequencing [next generation sequencing (NGS)] in defining the molecular diagnosis. Our results demonstrate that aBS II may be suspected in patients with a late-onset phenotype. Our experimental approach of NGS-based mutation screening combined with Sanger sequencing proved to be a reliable molecular approach for defining the clinical diagnosis in our patient, and results in important differential diagnostic and therapeutic implications for patients with BS. Our results could have a significant impact on the diagnosis and methodological approaches of genetic testing in other patients with clinical unclassified phenotypes of nephrocalcinosis and congenital renal electrolyte abnormalities.

Effect of animal and vegetable protein intake on oxalate excretion in idiopathic calcium stone disease.

PubMed

Marangella, M; Bianco, O; Martini, C; Petrarulo, M; Vitale, C; Linari, F

1989-04-01

Oxalate excretion was measured in healthy subjects and idiopathic calcium stone-formers on dietary regimens which differed in the type and amount of protein allowed; 24-h urine collections were obtained from 41 practising vegetarians and 40 normal persons on a free, mixed, "mediterranean" diet. Twenty idiopathic calcium stone-formers were also studied while on two low calcium, low oxalate diets which differed in that animal protein was high in one and restricted in the other. Vegetarians had higher urinary oxalate levels than controls and although the calcium levels were markedly lower, urinary saturation with calcium/oxalate was significantly higher. This mild hypercalciuria was interpreted as being secondary to both a higher intake and increased fractional intestinal absorption of oxalate. Changing calcium stone-formers from a high to a low animal protein intake produced a significant decrease in calcium excretion but there was no variation in urinary oxalate. As a result, the decrease in calcium oxalate saturation was only marginal and not significant. It was concluded that dietary animal protein has a minimal effect on oxalate excretion. Mild hyperoxaluria of idiopathic calcium stone disease is likely to be intestinal in origin. Calcium stone-formers should be advised to avoid an excess of animal protein but the risks of a vegetable-rich diet should also be borne in mind.

The value of hypercalciuria in patients with osteopenia versus osteoporosis.

PubMed

Girón-Prieto, María Sierra; Del Carmen Cano-García, María; Poyatos-Andújar, Antonio; Arias-Santiago, Salvador; de Haro-Muñoz, Tomás; Arrabal-Martín, Miguel; Arrabal-Polo, Miguel Ángel

2017-06-01

The aim of this study was to analyze the presence of lithogenic metabolic factors in the blood and urine of patients with osteopenia versus osteoporosis. This is a cross-sectional study including 67 patients who were divided into two groups according to the presence of either osteopenia or osteoporosis as measured by bone densitometry: group 1-40 patients with osteopenia (22 men and 18 women) and group 2-27 patients with osteoporosis (13 men and 14 women). Metabolic studies were performed on the blood and urine; statistical analysis was performed comparing means and conducting linear correlation and multivariate analyses with SPSS. Statistical significance was considered to be p ≤ 0.05. The mean age of patients in group 1 was 52.9 ± 12.8 years versus 50.3 ± 11.4 in group 2; the difference was not statistically significant. In group 2, higher levels of osteocalcin, β-crosslaps, urinary calcium, fasting urine calcium/creatinine, 24 h urine calcium/creatinine and 24 h oxaluria were observed compared to group 1. In the multivariate analysis, only the β-crosslaps and urinary calcium were independently associated with osteoporosis. It would be advisable to determine the urinary calcium levels in patients with osteoporosis since altered levels may necessitate modifying the diagnostic and therapeutic approach to osteoporosis.

Claudin Loss-of-Function Disrupts Tight Junctions and Impairs Amelogenesis

PubMed Central

Bardet, Claire; Ribes, Sandy; Wu, Yong; Diallo, Mamadou Tidiane; Salmon, Benjamin; Breiderhoff, Tilman; Houillier, Pascal; Müller, Dominik; Chaussain, Catherine

2017-01-01

Claudins are a family of proteins that forms paracellular barriers and pores determining tight junctions (TJ) permeability. Claudin-16 and -19 are pore forming TJ proteins allowing calcium and magnesium reabsorption in the thick ascending limb of Henle's loop (TAL). Loss-of-function mutations in the encoding genes, initially identified to cause Familial Hypomagnesemia with Hypercalciuria and Nephrocalcinosis (FHHNC), were recently shown to be also involved in Amelogenesis Imperfecta (AI). In addition, both claudins were expressed in the murine tooth germ and Claudin-16 knockout (KO) mice displayed abnormal enamel formation. Claudin-3, an ubiquitous claudin expressed in epithelia including kidney, acts as a barrier-forming tight junction protein. We determined that, similarly to claudin-16 and claudin-19, claudin-3 was expressed in the tooth germ, more precisely in the TJ located at the apical end of secretory ameloblasts. The observation of Claudin-3 KO teeth revealed enamel defects associated to impaired TJ structure at the secretory ends of ameloblasts and accumulation of matrix proteins in the forming enamel. Thus, claudin-3 protein loss-of-function disturbs amelogenesis similarly to claudin-16 loss-of-function, highlighting the importance of claudin proteins for the TJ structure. These findings unravel that loss-of-function of either pore or barrier-forming TJ proteins leads to enamel defects. Hence, the major structural function of claudin proteins appears essential for amelogenesis. PMID:28596736

Exome sequencing identifies a novel homozygous mutation in the phosphate transporter SLC34A1 in hypophosphatemia and nephrocalcinosis.

PubMed

Rajagopal, Abbhirami; Braslavsky, Débora; Lu, James T; Kleppe, Soledad; Clément, Florencia; Cassinelli, Hamilton; Liu, David S; Liern, Jose Miguel; Vallejo, Graciela; Bergadá, Ignacio; Gibbs, Richard A; Campeau, Phillipe M; Lee, Brendan H

2014-11-01

Two Argentinean siblings (a boy and a girl) from a nonconsanguineous family presented with hypercalcemia, hypercalciuria, hypophosphatemia, low parathyroid hormone (PTH), and nephrocalcinosis. The goal of this study was to identify genetic causes of the clinical findings in the two siblings. Whole exome sequencing was performed to identify disease-causing mutations in the youngest sibling, and a candidate variant was screened in other family members by Sanger sequencing. In vitro experiments were conducted to determine the effects of the mutation that was identified. Affected siblings (2 y.o. female and 10 y.o male) and their parents were included in the study. Informed consent was obtained for genetic studies. A novel homozygous mutation in the gene encoding the renal sodium-dependent phosphate transporter SLC34A1 was identified in both siblings (c.1484G>A, p.Arg495His). In vitro studies showed that the p.Arg495His mutation resulted in decreased phosphate uptake when compared to wild-type SLC34A1. The homozygous G>A transition that results in the substitution of histidine for arginine at position 495 of the renal sodium-dependent phosphate transporter, SLC34A1, is involved in disease pathogenesis in these patients. Our report of the second family with two mutated SLC34A1 alleles expands the known phenotype of this rare condition.

BIOPSY PROVEN MEDULLARY SPONGE KIDNEY: Clinical findings, histopathology, and role of osteogenesis in stone and plaque formation

PubMed Central

Evan, Andrew P.; Worcester, Elaine M.; Williams, James C.; Sommer, Andre J.; Lingeman, James E.; Phillips, Carrie L.; Coe, Fredric L.

2015-01-01

Medullary sponge kidney (MSK) is associated with recurrent stone formation, but the clinical phenotype is unclear because patients with other disorders may be incorrectly labeled MSK. We studied 12 patients with histologic findings pathognomonic of MSK. All patients had an endoscopically recognizable pattern of papillary malformation, which may be segmental or diffuse. Affected papillae are enlarged and billowy, due to markedly enlarged inner medullary collecting ducts (IMCD), which contain small, mobile ductal stones. Patients had frequent dilation of Bellini ducts, with occasional mineral plugs. Stones may form over white (Randall’s) plaque, but most renal pelvic stones are not attached, and have a similar morphology as ductal stones, which are a mixture of calcium oxalate and apatite. Patients had no abnormalities of urinary acidification or acid excretion; the most frequent metabolic abnormality was idiopathic hypercalciuria. Although both Runx2 and Osterix are expressed in papillae of MSK patients, no mineral deposition was seen at the sites of gene expression, arguing against a role of these genes in this process. Similar studies in idiopathic calcium stone formers showed no expression of these genes at sites of Randall’s plaque. The most likely mechanism for stone formation in MSK appears to be crystallization due to urinary stasis in dilated IMCD with subsequent passage of ductal stones into the renal pelvis where they may serve as nuclei for stone formation. PMID:25615853

Kidney stones: Composition, frequency and relation to metabolic diagnosis.

PubMed

Spivacow, Francisco R; Del Valle, Elisa E; Lores, Ernesto; Rey, Paula G

Nephrolithiasis is one of the most frequent urologic diseases. The aim of this paper is to study the composition and frequency of 8854 patient kidney stones and in a subset of them their metabolic risk factors to be related to their type of calculi. Physicochemical and crystallographic methods were used to assess kidney stone composition. In a subset of 715 patients, we performed an ambulatory metabolic protocol with diagnostic purposes. From the total sample 79% of stones were made of calcium salts (oxalate and phosphate), followed by uric acid stones in 16.5%, calcium salts and uric acid in 2%, other salts in 1.9% and cystine in 0.6%. Male to female ratio was almost three times higher in calcium salts and other types of stones, reaching a marked male predominance in uric acid stones, M/F 18.8 /1.0. The major risk factors for calcium stones are idiopathic hypercalciuria, followed by unduly acidic urine pH and hyperuricosuria. In uric acid stones unduly acidic urine pH and less commonly hyperuricosuria are the most frequent biochemical diagnosis. Our results show that analysis of kidney stones composition and the corresponding metabolic diagnosis may provide a scientific basis for the best management and prevention of kidney stone formation, as well as it may help us to study the mechanisms of urine stone formation.

Can adverse effects of excessive vitamin D supplementation occur without developing hypervitaminosis D?

PubMed

Razzaque, Mohammed S

2017-07-19

Vitamin D is a fat-soluble hormone that has endocrine, paracrine and autocrine functions. Consumption of vitamin D-supplemented food & drugs have increased significantly in the last couple of decades due to campaign and awareness programs. Despite such wide use of artificial vitamin D supplements, serum level of 25 hydroxyvitamin D does not always reflect the amount of uptake. In contrast to the safe sunlight exposure, prolonged and disproportionate consumption of vitamin D supplements may lead to vitamin D intoxication, even without developing hypervitaminosis D. One of the reasons why vitamin D supplementation is believed to be safe is, it rarely raises serum vitamin D levels to the toxic range even after repeated intravenous ingestion of extremely high doses of synthetic vitamin D analogs. However, prolonged consumption of vitamin D supplementation may induce hypercalcemia, hypercalciuria and hyperphosphatemia, which are considered to be the initial signs of vitamin D intoxication. It is likely that calcium and phosphorus dysregulation, induced by exogenous vitamin D supplementation, may lead to tissue and organ damages, even without developing hypervitaminosis D. It is needed to be emphasized that, because of tight homeostatic control of calcium and phosphorus, when hypercalcemia and/or hyperphosphatemia is apparent following vitamin D supplementation, the process of tissue and/or organ damage might already have been started. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification of co-occurrence in a patient with Dent's disease and ADA2-deficiency by exome sequencing.

PubMed

Günthner, Roman; Wagner, Matias; Thurm, Tobias; Ponsel, Sabine; Höfele, Julia; Lange-Sperandio, Bärbel

2018-04-05

Patients with co-occurrence of two independent pathologies pose a challenge for clinicians as the phenotype often presents as an unclear syndrome. In these cases, exome sequencing serves as a powerful instrument to determine the underlying genetic causes. Here, we present the case of a 4-year old boy with proteinuria, microhematuria, hypercalciuria, nephrocalcinosis, livedo-like rash, recurrent abdominal pain, anemia and continuously elevated CRP. Single exome sequencing revealed the pathogenic nonsense mutation p.(Arg98*) in the CLCN5 gene causing the X-linked inherited, renal tubular disorder Dent's disease. Furthermore, the two pathogenic and compound heterozygous missense variants p.(Gly47Ala) and p.(Pro251Leu) in the CECR1 gene could be identified. Mutations in the CECR1 gene are associated with a hereditary form of polyarteritis nodosa, called ADA2-deficiency. Both parents were carriers of a single heterozygous variant in CECR1 and the mother was carrier of the CLCN5 variant. This case evidently demonstrates the advantage of whole exome sequencing compared to single gene testing as the pathology in the CECR1 gene might have only been diagnosed after the occurrence of signs of systemic vasculitis like strokes or hemorrhages. Therefore, treatment and prevention can now start early to improve the outcome of these patients. Copyright © 2018 Elsevier B.V. All rights reserved.

Claudin Loss-of-Function Disrupts Tight Junctions and Impairs Amelogenesis.

PubMed

Bardet, Claire; Ribes, Sandy; Wu, Yong; Diallo, Mamadou Tidiane; Salmon, Benjamin; Breiderhoff, Tilman; Houillier, Pascal; Müller, Dominik; Chaussain, Catherine

2017-01-01

Claudins are a family of proteins that forms paracellular barriers and pores determining tight junctions (TJ) permeability. Claudin-16 and -19 are pore forming TJ proteins allowing calcium and magnesium reabsorption in the thick ascending limb of Henle's loop (TAL). Loss-of-function mutations in the encoding genes, initially identified to cause Familial Hypomagnesemia with Hypercalciuria and Nephrocalcinosis (FHHNC), were recently shown to be also involved in Amelogenesis Imperfecta (AI). In addition, both claudins were expressed in the murine tooth germ and Claudin-16 knockout (KO) mice displayed abnormal enamel formation. Claudin-3, an ubiquitous claudin expressed in epithelia including kidney, acts as a barrier-forming tight junction protein. We determined that, similarly to claudin-16 and claudin-19, claudin-3 was expressed in the tooth germ, more precisely in the TJ located at the apical end of secretory ameloblasts. The observation of Claudin-3 KO teeth revealed enamel defects associated to impaired TJ structure at the secretory ends of ameloblasts and accumulation of matrix proteins in the forming enamel. Thus, claudin-3 protein loss-of-function disturbs amelogenesis similarly to claudin-16 loss-of-function, highlighting the importance of claudin proteins for the TJ structure. These findings unravel that loss-of-function of either pore or barrier-forming TJ proteins leads to enamel defects. Hence, the major structural function of claudin proteins appears essential for amelogenesis.

Two Cases of Mistaken Polyuria and Nephrocalcinosis in Infants with Glucose-Galactose Malabsorption: A Possible Role of 1,25(OH)2D3
.

PubMed

Fiscaletti, Melissa; Lebel, Marie-Jeanne; Alos, Nathalie; Benoit, Geneviève; Jantchou, Prévost

2017-01-01

Glucose-galactose malabsorption (GGM) is a rare and potentially fatal disorder. The autosomal recessive mutation of the SGLT1 gene interferes with the active glucose transport in the gut resulting in osmotic diarrhea and failure to thrive (FTT). Two nonrelated infants with GGM are presented as well as a novel mutation in SGLT1. The first case consulted for FTT and presented with hypercalcemia and hypercalciuria. His mother had self-medicated with high doses of vitamin D. The second case consulted for macroscopic hematuria, and presented with dehydration and secondary acute kidney injury. In both cases, the profuse diarrhea, initially mistaken for polyuria, promptly resolved after the introduction of glucose-galactose-free milk. Investigations showed bilateral nephrocalcinosis and high levels of 1,25(OH)2D3 in both patients. We hypothesize that the upregulation of epithelial calcium channels (TRPV6) and 1,25(OH)2D3 are possible factors involved in the pathophysiology of nephrocalcinosis sometimes seen in GGM. Furthermore, a novel intronic SGLT1 mutation (c.207+2dup) is described. These 2 cases demonstrate that a malabsorption disorder such as GGM can present with nephrocalcinosis and/or hypercalcemia, with increased 1,25(OH)2D3 levels in infants. Prompt recognition of GGM is sometimes difficult but crucial.
. © 2017 S. Karger AG, Basel.

Cloning and characterization of CLCN5, the human kidney chloride channel gene implicated in Dent disease (an X-linked hereditary nephrolithiasis).

PubMed

Fisher, S E; van Bakel, I; Lloyd, S E; Pearce, S H; Thakker, R V; Craig, I W

1995-10-10

Dent disease, an X-linked familial renal tubular disorder, is a form of Fanconi syndrome associated with proteinuria, hypercalciuria, nephrocalcinosis, kidney stones, and eventual renal failure. We have previously used positional cloning to identify the 3' part of a novel kidney-specific gene (initially termed hClC-K2, but now referred to as CLCN5), which is deleted in patients from one pedigree segregating Dent disease. Mutations that disrupt this gene have been identified in other patients with this disorder. Here we describe the isolation and characterization of the complete open reading frame of the human CLCN5 gene, which is predicted to encode a protein of 746 amino acids, with significant homology to all known members of the ClC family of voltage-gated chloride channels. CLCN5 belongs to a distinct branch of this family, which also includes the recently identified genes CLCN3 and CLCN4. We have shown that the coding region of CLCN5 is organized into 12 exons, spanning 25-30 kb of genomic DNA, and have determined the sequence of each exon-intron boundary. The elucidation of the coding sequence and exon-intron organization of CLCN5 will both expedite the evaluation of structure/function relationships of these ion channels and facilitate the screening of other patients with renal tubular dysfunction for mutations at this locus.

A curious case of growth failure and hypercalcemia: Answers.

PubMed

Downie, Mallory L; Mulder, Jaap; Schneider, Rayfel; Lim, Lillian; Tehrani, Nasrin; Wasserman, Jonathan D; Fuchs, Shai; John, Rohan; Noone, Damien G; Hebert, Diane

2018-06-01

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that rarely presents in childhood. Here, we report a case of pediatric sarcoidosis, presenting with renal failure and hypercalcemia. A previously well 14-year-old Caucasian boy was admitted to the Hospital for Sick Children, Canada, for hypertension and renal failure following work-up by his family physician for initial concerns of growth failure. On admission, his weight was 35 kg (<3rd percentile), his height was 148 cm (<3rd percentile), and his blood pressure was 154/116 mmHg (>99th percentile for height). Laboratory findings showed elevated creatinine (218 umol/L), hypercalcemia (3.21 mmol/L), and normocytic anemia (hemoglobin 105 g/L). His further assessment showed a urinary concentrating defect with hypercalciuria (calcium/creatinine 1.76 mmol/mmol) and nephrocalcinosis on ultrasound. His eye examination showed uveitis with conjunctival biopsy remarkable for granulomas, which led to pursuit of a diagnosis of possible sarcoidosis. Angiotensin Angiotensin-converting enzyme was found to be high at 96 U/L, and he had a renal biopsy that was consistent with interstitial nephritis with granulomas. Treatment was started with prednisone leading to resolution of his hypercalcemia but persistence of his mild chronic kidney disease. This case represents an atypical presentation of a rare pediatric disease and highlights the spectrum of renal manifestations and treatment options in sarcoidosis.

A curious case of growth failure and hypercalcemia: Questions.

PubMed

Downie, Mallory L; Mulder, Jaap; Schneider, Rayfel; Lim, Lillian; Tehrani, Nasrin; Wasserman, Jonathan D; Fuchs, Shai; John, Rohan; Noone, Damien G; Hebert, Diane

2018-06-01

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that rarely presents in childhood. Here, we report a case of pediatric sarcoidosis presenting with renal failure and hypercalcemia. A previously well 14-year-old Caucasian boy was admitted to the Hospital for Sick Children, Canada, for hypertension and renal failure following work-up by his family physician for initial concerns of growth failure. On admission, his weight was 35 kg (<3rd percentile), his height was 148 cm (≪3rd percentile), and his blood pressure was 154/116 mmHg (>99th percentile for height). Laboratory findings showed elevated creatinine (218 μmol/L), hypercalcemia (3.21 mmol/L), and normocytic anemia (hemoglobin 105 g/L). His further assessment showed a urinary concentrating defect with hypercalciuria (calcium/creatinine 1.76 mmol/mmol) and nephrocalcinosis on ultrasound. His eye examination showed uveitis with conjunctival biopsy remarkable for granulomas, which led to pursuit of a diagnosis of possible sarcoidosis. Angiotensin-converting enzyme was found to be high at 96 U/L, and he had a renal biopsy that was consistent with interstitial nephritis with granulomas. Treatment was started with prednisone leading to resolution of his hypercalcemia but persistence of his mild chronic kidney disease. This case represents an atypical presentation of a rare pediatric disease and highlights the spectrum of renal manifestations and treatment options in sarcoidosis.

Maternal Hypercalcemia Due to Failure of 1,25-Dihydroxyvitamin-D3 Catabolism in a Patient With CYP24A1 Mutations

PubMed Central

Hsiao, Edward C.; O'Donnell, Betsy; Salmeen, Kirsten; Nussbaum, Robert; Krebs, Michael; Baumgartner-Parzer, Sabina; Kaufmann, Martin; Jones, Glenville; Bikle, Daniel D.; Wang, YongMei; Mathew, Allen S.; Shoback, Dolores; Block-Kurbisch, Ingrid

2015-01-01

Context: Calcium metabolism changes in pregnancy and lactation to meet fetal needs, with increases in 1,25-dihydroxyvitamin D [1,25-(OH)2D] during pregnancy playing an important role. However, these changes rarely cause maternal hypercalcemia. When maternal hypercalcemia occurs, further investigation is essential, and disorders of 1,25-(OH)2D catabolism should be carefully considered in the differential diagnosis. Case: A patient with a childhood history of recurrent renal stone disease and hypercalciuria presented with recurrent hypercalcemia and elevated 1,25-(OH)2D levels during pregnancy. Laboratory tests in the fourth pregnancy showed suppressed PTH, elevated 1,25-(OH)2D, and high-normal 25-hydroxyvitamin D levels, suggesting disordered vitamin D metabolism. Analysis revealed low 24,25-dihydroxyvitamin D3 and high 25-hydroxyvitamin D3 levels, suggesting loss of function of CYP24A1 (25-hydroxyvitamin-D3-24-hydroxylase). Gene sequencing confirmed that she was a compound heterozygote with the E143del and R396W mutations in CYP24A1. Conclusions: This case broadens presentations of CYP24A1 mutations and hypercalcemia in pregnancy. Furthermore, it illustrates that patients with CYP24A1 mutations can maintain normal calcium levels during the steady state but can develop hypercalcemia when challenged, such as in pregnancy when 1,25-(OH)2D levels are physiologically elevated. PMID:26097993

Renal-Stone Risk Assessment During Space Shuttle Flights

NASA Technical Reports Server (NTRS)

Whitson, Peggy A.; Pietrzyk, Robert A.; Pak, Charles Y. C.

1996-01-01

The metabolic and environmental factors influencing renal stone formation before, during, and after Space Shuttle flights were assessed. We established the contributing roles of dietary factors in relationship to the urinary risk factors associated with renal stone formation. 24-hr urine samples were collected prior to, during space flight, and following landing. Urinary factors associated with renal stone formation were analyzed and the relative urinary supersaturation ratios of calcium oxalate, calcium phosphate (brushite), sodium urate, struvite and uric acid were calculated. Food and fluid consumption was recorded for a 48-hr period ending with the urine collection. Urinary composition changed during flight to favor the crystallization of stone-forming salts. Factors that contributed to increased potential for stone formation during space flight were significant reductions in urinary pH and increases in urinary calcium. Urinary output and citrate, a potent inhibitor of calcium-containing stones, were slightly reduced during space flight. Dietary intakes were significantly reduced for a number of variables, including fluid, energy, protein, potassium, phosphorus and magnesium. This is the first in-flight characterization of the renal stone forming potential in astronauts. With the examination of urinary components and nutritional factors, it was possible to determine the factors that contributed to increased risk or protected from risk. In spite of the protective components, the negative contributions to renal stone risk predominated and resulted in a urinary environment that favored the supersaturation of stone-forming salts. The importance of the hypercalciuria was noted since renal excretion was high relative to the intake.

A patient with Bartter syndrome accompanying severe growth hormone deficiency and focal segmental glomerulosclerosis.

PubMed

Akil, Ipek; Ozen, Serkan; Kandiloglu, Ali Riza; Ersoy, Betul

2010-06-01

Bartter syndrome is a rare autosomal recessive, salt-losing disorder characterized by hypokalemic hypochloremic metabolic alkalosis. A 10-year-old boy had severe growth retardation (height standard deviation score -8.15). He had a thin, triangular face, prominent ears and forehead, and big eyes. Megacystis, bilateral hydroureteronephrosis, and residual urine were detected in ultrasonography, but there was no vesicoureteral reflux. Lumbosacral magnetic resonance (MR) showed posterior disc bulging at L4-5. Serum sodium and chloride levels were normal, but mild hypokalemia was overlooked initially. During follow-up, hypokalemic hypochloremic metabolic alkalosis developed, with high urinary chloride and potassium excretion (52 and 43 mEq/L, respectively). The patient, with renal salt loss, was thought to have classic Bartter syndrome due to absence of nephrocalcinosis, presence of persistent hypercalciuria and sensorineural deafness, and presence of relatively mild clinical and laboratory findings, except polyuria initially. The child was treated with indomethacin, spironolactone, and oral potassium in addition to growth hormone (GH). During treatment, he had considerable increase in weight and height compared with the period of GH therapy only. We present this case because, although growth retardation is a major feature of Bartter syndrome, associated GH deficiency is rarely reported in the literature. Diagnosis of Bartter syndrome was made later, as our patient was followed for megacystis and megaureter secondary to the neurogenic bladder and GH deficiency initially; and proteinuria associated with focal segmental glomerulosclerosis responded to treatment for Bartter syndrome.

Exome Sequencing Identifies a Novel Homozygous Mutation in the Phosphate Transporter SLC34A1 in Hypophosphatemia and Nephrocalcinosis

PubMed Central

Rajagopal, Abbhirami; Braslavsky, Débora; Lu, James T.; Kleppe, Soledad; Clément, Florencia; Cassinelli, Hamilton; Liu, David S.; Liern, Jose Miguel; Vallejo, Graciela; Bergadá, Ignacio; Gibbs, Richard A.; Campeau, Phillipe M.

2014-01-01

Context: Two Argentinean siblings (a boy and a girl) from a nonconsanguineous family presented with hypercalcemia, hypercalciuria, hypophosphatemia, low parathyroid hormone (PTH), and nephrocalcinosis. Objective: The goal of this study was to identify genetic causes of the clinical findings in the two siblings. Design: Whole exome sequencing was performed to identify disease-causing mutations in the youngest sibling, and a candidate variant was screened in other family members by Sanger sequencing. In vitro experiments were conducted to determine the effects of the mutation that was identified. Patients and Other Participants: Affected siblings (2 y.o. female and 10 y.o male) and their parents were included in the study. Informed consent was obtained for genetic studies. Results: A novel homozygous mutation in the gene encoding the renal sodium-dependent phosphate transporter SLC34A1 was identified in both siblings (c.1484G>A, p.Arg495His). In vitro studies showed that the p.Arg495His mutation resulted in decreased phosphate uptake when compared to wild-type SLC34A1. Conclusions: The homozygous G>A transition that results in the substitution of histidine for arginine at position 495 of the renal sodium-dependent phosphate transporter, SLC34A1, is involved in disease pathogenesis in these patients. Our report of the second family with two mutated SLC34A1 alleles expands the known phenotype of this rare condition. PMID:25050900

Rhazes, a genius physician in diagnosis and treatment of kidney calculi in medical history.

PubMed

Changizi Ashtiyani, Saeed; Cyrus, Ali

2010-04-01

Abu Bakr Mohammad Ibn Zakariya Razi, known in the west as Rhazes (865 to 925 AD), was born in the ancient city of Rayy, near Tehran, Iran. He was a renowned physician in medical history and not only followed Hippocrates and Galen, but also greatly extended the analytical approach of his predecessors. Based on the existing documents, he was known as the most distinguished character in the world of medicine up to the 17th century. A great number of innovations and pioneering works in the medical science have been recorded in the name of Rhazes. His fundamental works in urology as part of his research in the realm of medicine have remained unknown. Pathophysiology of the urinary tract, venereal diseases, and kidney and bladder calculi are among his main interests in this field. He also purposed and developed methods for diagnosis and treatment of kidney calculi for the first time in medical history. He also presented a very exact and precise description of neuropathic bladder followed by vertebral fracture. He advanced urine analysis and studied function and diseases of the kidneys. Rhazes recommendations for the prevention of calculi are quite scientific and practical and in accordance with current recommendations to avoid hypercalciuria and increased saturation of urine. Rhazes was not only one of the most important Persian physician-philosophers of his era, but for centuries, his writings became fundamental teaching texts in European medical schools. Some important aspects of his contributions to medicine are reviewed.

Similarity of urinary risk factors among stone-forming patients in five regions of the United States

NASA Technical Reports Server (NTRS)

Harvey, J. A.; Hill, K. D.; Pak, C. Y.

1990-01-01

Study Objective: To compare urinary biochemical risk factors among stone-forming patients in the Southeast (SE) or "stone belt" versus four other regions of the United States. Design: Prospective biochemical survey for regional comparisons. Setting: Referral-based nephrolithiasis clinics, urologists, nephrologists, and family practitioners. Patients: Consecutive sample of 3473 stone-forming patients who submitted 24-hour urine collections for biochemical analyses of stone-forming risk factors. Interventions: None. Subjects taking medication known to interfere with stone-forming risk factors were deleted from the final data compilation. Measurements and Main Results: Overall, the mean values for each urinary parameter spanned a narrow range without significant difference between the five regions. Among "metabolic" factors, 40% in the SE had hypercalciuria (> 6.25 mmol/d), compared to 35%-43% in other regions, and hyperuricosuria (> 4.2 mmol/d) was found in 16% in the SE versus 17%-19% elsewhere. Among "environmental" factors, low urine volume ( < 2 L/d) was found in 77% patients in the SE compared to 69%-78% elsewhere, and high sodium was encountered in 27% in the SE versus 24%-29% elsewhere. No differences were noted in occurrence of other abnormal risk factors: hyperoxaluria, hypocitraturia, low pH, high sulfate, high phosphorus, or low magnesium. Conclusions: Despite expected regional differences in nutritional and environmental influences, the results of this study showed a striking similarity in urinary biochemical risk factor profiles of stone-formers in all five regions of the United States.

MECHANISMS IN ENDOCRINOLOGY: Kidney involvement in patients with primary hyperparathyroidism: an update on clinical and molecular aspects.

PubMed

Verdelli, C; Corbetta, S

2017-01-01

Primary hyperparathyroidism (PHPT) is the third most common endocrine disease. Kidney is a target of both chronic elevated PTH and calcium in PHPT. The classic PHPT complications of symptomatic kidney stones and nephrocalcinosis have become rare and the PHPT current presentation is asymptomatic with uncertain and long-lasting progression. Nonetheless, the routine use of imaging and of biochemical determinations have revealed the frequent occurrence of asymptomatic kidney stones, hypercalciuria and reduced kidney function in asymptomatic PHPT patients. Though the pathogenesis is far from being elucidated, PHPT is associated with reduced renal function, in terms of estimated glomerular filtration rate, and related increased morbidity and mortality. In the last decade, the effort of the Kidney Disease: Improving Global Outcomes (KDIGO) panel of experts highlighted that even mild reduction of kidney function is associated with increased risk of cardiovascular disease. These considerations provided the basis for the Fourth Workshop recommendations of a more extensive diagnostic workout about kidney features and of wider criteria for parathyroid surgery including asymptomatic kidney disease. Moreover, kidney involvement in PHPT is likely to be affected by variants of genes coding the key molecules regulating the calcium and ions renal handling; these features might have clinical relevance and should be considered both during diagnostic workout and follow-up. Finally, the effects of parathyroid surgery and of medical treatment on kidney involvement of PHPT are reviewed. © 2017 European Society of Endocrinology.

A Randomized Trial of Vitamin D Supplementation in Two Community Health Center Networks in South Carolina

PubMed Central

WAGNER, Carol L.; MCNEIL, Rebecca; HAMILTON, Stuart A.; WINKLER, Joyce; COOK, Carolina Rodriguez; WARNER, Gloria; BIVENS, Betty; DAVIS, Deborah J.; SMITH, Pamela G.; MURPHY, Martha; SHARY, Judy; HOLLIS, Bruce W.

2015-01-01

Objective To determine whether 4000 IU vitamin D3/day (vs. 2000 IU/day) during pregnancy is safe and improves maternal/neonatal 25(OH)D in a dose-dependent manner. Study Design 257 pregnant women 12–16 weeks’ gestation were enrolled. Randomization to 2000- vs. 4000 IU/day followed one-month run-in at 2000 IU/day. Participants were monitored for hypercalciuria, hypercalcemia and 25(OH)D status. Results Maternal 25(OH)D (n=161) increased from 22.7(SD 9.7) at baseline to 36.2(SD 15) and 37.9(SD 13.5) in the 2000- and 4000 IU groups, respectively. While maternal 25(OH)D change from baseline did not differ between groups, 25(OH)D monthly increase differed between groups (p<0.01). No supplementation-related adverse events occurred. Mean cord blood 25(OH)D (ng/mL) was 22.1±10.3 in 2000- and 27.0±13.3 in 4000 IU group (p=0.024). After controlling for race and study site, preterm birth and labor were inversely associated with pre-delivery- and mean 25(OH)D, but not baseline 25(OH)D,. Conclusions Maternal supplementation with 2000 and 4000 IU vitamin D/day during pregnancy improved maternal/neonatal vitamin D status. Evidence of risk reduction in infection, preterm labor and preterm birth was suggestive, requiring additional studies powered for these endpoints. PMID:23131462

Renal tubular NEDD4-2 deficiency causes NCC-mediated salt-dependent hypertension.

PubMed

Ronzaud, Caroline; Loffing-Cueni, Dominique; Hausel, Pierrette; Debonneville, Anne; Malsure, Sumedha Ram; Fowler-Jaeger, Nicole; Boase, Natasha A; Perrier, Romain; Maillard, Marc; Yang, Baoli; Stokes, John B; Koesters, Robert; Kumar, Sharad; Hummler, Edith; Loffing, Johannes; Staub, Olivier

2013-02-01

The E3 ubiquitin ligase NEDD4-2 (encoded by the Nedd4L gene) regulates the amiloride-sensitive epithelial Na+ channel (ENaC/SCNN1) to mediate Na+ homeostasis. Mutations in the human β/γENaC subunits that block NEDD4-2 binding or constitutive ablation of exons 6-8 of Nedd4L in mice both result in salt-sensitive hypertension and elevated ENaC activity (Liddle syndrome). To determine the role of renal tubular NEDD4-2 in adult mice, we generated tetracycline-inducible, nephron-specific Nedd4L KO mice. Under standard and high-Na+ diets, conditional KO mice displayed decreased plasma aldosterone but normal Na+/K+ balance. Under a high-Na+ diet, KO mice exhibited hypercalciuria and increased blood pressure, which were reversed by thiazide treatment. Protein expression of βENaC, γENaC, the renal outer medullary K+ channel (ROMK), and total and phosphorylated thiazide-sensitive Na+Cl- cotransporter (NCC) levels were increased in KO kidneys. Unexpectedly, Scnn1a mRNA, which encodes the αENaC subunit, was reduced and proteolytic cleavage of αENaC decreased. Taken together, these results demonstrate that loss of NEDD4-2 in adult renal tubules causes a new form of mild, salt-sensitive hypertension without hyperkalemia that is characterized by upregulation of NCC, elevation of β/γENaC, but not αENaC, and a normal Na+/K+ balance maintained by downregulation of ENaC activity and upregulation of ROMK.

Osteoporosis‐like Changes in Walker Carcinoma 256‐Bearing Rats, Not Accompanied with Hypercalcemia or Parathyroid Hormone‐related Protein Production

PubMed Central

Waki, Yoshihiro; Kasugai, Shohei; Ohya, Keiichi

1995-01-01

Walker carcinoma 256 (W256) was reported to induce hypercalcemia dependent on bone metastasis and/or parathyroid hormone‐related protein (PTHrP) in the rat, providing a model of the humoral hypercalcemia of malignancy. In this study, after the subcutaneous inoculation of cells of the W256/S line, which is maintained in this laboratory, into young female Wistar Imamichi rats (6 weeks old), serum calcium and phosphorus levels changed only within the control range, whereas serum alkaline phosphatase activity and urinary calcium level significantly increased and urinary phosphorus decreased during the tumor growth, resulting in hypercalciuria and hypophosphaturia. W256/S did not express PTHrP‐mRNA, whereas LLC‐W256 cells did express it. Serum PTHrP level was not changed in W256/S‐bearing rats. Osteoporosis‐like changes, bone weight loss, low contents of bone calcium and phosphorus, and a decrease in the bone mineral density (BMD), were observed in the femur 14 days after the tumor inoculation. There was a pronounced decrease in the serum 17β‐estradiol level during the tumor growth. The reduction of BMD of femurs in W256/S‐bearing rats was significantly inhibited by treatment with salmon calcitonin or 17β‐estradiol. On the basis of these results, W256/S carcinoma‐bearing rats seem to be a useful model for osteoporosis of hypoovarianism. PMID:7540609

Precipitation and Solubility of Calcium Hydrogenurate Hexahydrate

PubMed Central

Babić-Ivančić, V.; Füredi-Milhofer, H.; Brničević, N.; Marković, M.

1992-01-01

Solid phases formed in the quaternary system: uric acid—calcium hydroxide —hydrochloric acid—water aged for 2 months at 310 K were studied to determine conditions for calcium hydrogenurate hexahydrate, Ca(C5H3N4O)2 · 6H2O precipitation. The precipitates were identified by chemical and thermogravimetric analyses, x-ray powder diffraction, infrared spectroscopy, light microscopy, and scanning electron microscopy. In the precipitation diagram the concentration region in which calcium hydrogenurate hexahydrate precipitated as a single solid phase was established. The solubility of calcium hydrogenurate hexahydrate was investigated in the pH range from 6.2 to 10.1 at different temperatures. The total soluble and ionic concentration of calcium (atomic absorption spectroscopy and Ca-selective electrode), total urate concentration (spectrophotometry), and pH were determined in equilibrated solutions. The data are presented in the form of tables and chemical potential diagrams. By using these data the thermodynamic solubility products of calcium hydrogenurate hexahydrate, Ks = a(Ca2+) · a2(C5H3N4O3−), were determined: pKs=10.12±0.07at288K,pKs=9.81±0.09at298K,pKs=9.28±0.04at310K,andpKs=9.01±0.03at318K.The formation of calcium hydrogenurate hexahydrate crystals in urinary tract of patients with pathologically high concentrations of calcium and urates (hypercalciuria and hyperuricosiuria) is possible. PMID:28053438

Elevated carbohydrate-deficient transferrin (CDT) and its normalization on dietary treatment as a useful biochemical test for hereditary fructose intolerance and galactosemia.

PubMed

Pronicka, Ewa; Adamowicz, Maciej; Kowalik, Agnieszka; Płoski, Rafał; Radomyska, Barbara; Rogaszewska, Małgorzata; Rokicki, Dariusz; Sykut-Cegielska, Jolanta

2007-07-01

Abnormalities in protein glycosylation are reported in fructosemia (HFI) and galactosemia, although, particularly in HFI, the published data are limited to single cases. The purpose was to investigate the usefulness of the carbohydrate-deficient transferrin (CDT) profile for identification and monitoring of these disorders. First we analyzed CDT values before and shortly after the diagnosis in 10 cases of HFI and 17 cases of galactosemia. In all patients, elevated CDT levels were found that significantly (p < 0.0001) decreased with the therapeutic diet (27.3 +/- 11.5% versus 9.3 +/- 5.1% for HFI and 43.8 +/- 14.1% versus 11.2 +/- 4.0% for galactosemia). To evaluate the use of CDT test in monitoring compliance, the test was performed in 25 HFI patients on fructose-restricted diet. We found an elevated CDT level on 104 from 134 tests (mean 11.3 +/- 5.5%, control 1.5%-6.2%). The fructose intake was found to be 90 +/- 70 mg/kg/d, and the diet was unbalanced. A number of patients presented lower height, elevated urinary uric acid excretion, and hypercalciuria. In conclusion, abnormal percentage of CDT (%CDT) values may allow prompt detection of HFI (or galactosemia). Persistence of some abnormalities in HFI on treatment may be caused by trace amounts of fructose ingestion and/or a deficient diet. Regular %CDT measurements are suggested for HFI treatment monitoring.

Osteoporosis in paediatric patients with spina bifida.

PubMed

Marreiros, Humberto; Marreiros, Humberto Filipe; Loff, Clara; Calado, Eulalia

2012-01-01

The prevalence and morbidity associated with osteoporosis and fractures in patients with spina bifida (SB) highlight the importance of osteoporosis prevention and treatment in early childhood; however, the issue has received little attention. The method for the selection of appropriate patients for drug treatment has not been clarified. To review the literature concerning fracture risks and low bone density in paediatric patients with SB. We looked for studies describing state-of-the-art treatments and for prevention of secondary osteoporosis. Articles were identified through a search in the electronic database (PUBMED) supplemented with reviews of the reference lists of selected papers. The main outcome measures were incidence of fractures and risk factors for fracture, an association between bone mineral density (BMD) and occurrence of fracture, risk factors of low BMD, and effects of pharmacological and non-pharmacological treatments on BMD and on the incidence of fractures. We considered as a secondary outcome the occurrence of fractures in relation to the mechanism of injury. Results indicated that patients with SB are at increased risk for fractures and low BMD. Risk factors that may predispose patients to fractures include higher levels of neurological involvement, non-ambulatory status, physical inactivity, hypercalciuria, higher body fat levels, contractures, and a previous spontaneous fracture. Limitations were observed in the number and quality of studies concerning osteoporosis prevention and treatment in paediatric patients with SB. The safety and efficiency of drugs to treat osteoporosis in adults have not been evaluated satisfactorily in children with SB.

Effect of modified alkaline supplementation on bone metabolic turnover in rats.

PubMed

Chui, D H; Marotta, F; Liu, T; Minelli, E; Yadav, H; Signorelli, P; Lorenzetti, A; Jain, S

2008-01-01

This study aims to determine the effects of a high protein diet and alkaline supplementation on bone metabolic turnover in rats. Eight-week-old male Sprague-Dawley rats were investigated by bone status, including bone mineral density (BMD) and biomechanical markers from blood and urine. Thirty rats were randomly divided into three groups and treated for 8 weeks as follows: baseline control group (n. 10, C), high-protein supplemented diet group (n. 10, chronic acidosis, CA group) and supplemented chronic acidosis (n.10, SCA). Diet-treated rats were fed an acidic high-protein diet and the supplementation consisted in a modified alkaline formula (Basenpulver, NaMed, Italy). At the end of the experimental period, the rats were sacrificed, blood samples were drawn and femur and tibia were removed for analysis of bone mineral density (BMD) by dual energy X-ray absorptiometry (DEXA). In the CA group, 24-hour urinary calcium (Ca) and phosphorus (P) excretion were increased 2.1-fold (p<0.05 vs normal diet controls) as well as kidney weight. However, serum Ca and P concentration, as well as urinary Dpd excretion were not significantly changed. Femural and tibial BMD was significantly decreased in the CA group (p<0.05), but alkaline supplementation prevented such phenomenon (p<0.05 vs CA). These results suggest that blood Ca and P concentrations in chronic acidosis condition during the 12-week supplementation might be maintained by hypercalciuria and hyperphosphaturia at the expenses of bone structure. However, modified alkaline supplementation is able to prevent such derangements.

The increased risk of urinary stone disease in betel quid chewers.

PubMed

Allen, Siân E; Singh, Sadmeet; Robertson, William G

2006-08-01

The chewing of betel quid is a common practice in many countries of the world, particularly in Southeast Asia. The quid consists of a preparation of areca nut, betel leaf and calcium hydroxide "lime" paste ("chuna"). For the first time, we present a study that links its use to urinary stone disease. Eight patients (seven male and one female) who presented to our Stone Unit with recurrent urinary stones were included in the study. All were from the Indian subcontinent and were found to regularly chew betel. The patients underwent metabolic screening including blood, random urine and 24-h urine tests, quantitative chemical analysis of their calculi (where possible) and each completed a 7-day Diet Diary on his/her free, home diet. The study demonstrated a high incidence of hypercalciuria, a tendency to pass an alkaline urine and low urinary citrate excretion among the patients. Together these urinary risk factors increase the probability of developing both calcium phosphate-containing and calcium oxalate-containing stones. In support of this hypothesis, the patients were found to form stones consisting mainly of calcium phosphate but mixed with calcium oxalate. It is concluded that the use of calcium hydroxide "chuna" in the betel quid is the major contributor to the cause of urinary stones in its users. Moreover, the development of urinary lithiasis in such patients may be a precursor to milk-alkali syndrome in those individuals whose chewing habit is more extensive than in the patients in this study and who do not seek to decrease their habit over the long term.

Novel calcium-sensing receptor cytoplasmic tail deletion mutation causing autosomal dominant hypocalcemia: molecular and clinical study.

PubMed

Obermannova, Barbora; Sumnik, Zdenek; Dusatkova, Petra; Cinek, Ondrej; Grant, Michael; Lebl, Jan; Hendy, Geoffrey N

2016-04-01

Autosomal dominant hypocalcemia (ADH) is a rare disorder caused by activating mutations of the calcium-sensing receptor (CASR). The treatment of ADH patients with 1α-hydroxylated vitamin D derivatives can cause hypercalciuria leading to nephrocalcinosis. We studied a girl who presented with hypoparathyroidism and asymptomatic hypocalcemia at age 2.5 years. Mutations of CASR were investigated by DNA sequencing. Functional analyses of mutant and WT CASRs were done in transiently transfected human embryonic kidney (HEK293) cells. The proband and her father are heterozygous for an eight-nucleotide deletion c.2703_2710delCCTTGGAG in the CASR encoding the intracellular domain of the protein. Transient expression of CASR constructs in kidney cells in vitro suggested greater cell surface expression of the mutant receptor with a left-shifted extracellular calcium dose-response curve relative to that of the WT receptor consistent with gain of function. Initial treatment of the patient with calcitriol led to increased urinary calcium excretion. Evaluation for mosaicism in the paternal grandparents of the proband was negative. We describe a novel naturally occurring deletion mutation within the CASR that apparently arose de novo in the father of the ADH proband. Functional analysis suggests that the cytoplasmic tail of the CASR contains determinants that regulate the attenuation of signal transduction. Early molecular analysis of the CASR gene in patients with isolated idiopathic hypoparathyroidism is recommended because of its relevance to clinical outcome and treatment choice. In ADH patients, calcium supplementation and low-dose cholecalciferol avoids hypocalcemic symptoms without compromising renal function. © 2016 European Society of Endocrinology.

SaRNA-mediated activation of TRPV5 reduces renal calcium oxalate deposition in rat via decreasing urinary calcium excretion.

PubMed

Zeng, Tao; Duan, Xiaolu; Zhu, Wei; Liu, Yang; Wu, Wenqi; Zeng, Guohua

2018-06-01

Hypercalciuria is a main risk factor for kidney stone  formation. TRPV5 is the gatekeeper protein for mediating calcium transport and reabsorption in the kidney. In the present study, we tested the effect of TRPV5 activation with small activating RNA (saRNA), which could induce gene expression by targeting the promoter of the gene, on ethylene glycol (EG)-induced calcium oxalate (CaOx) crystals formation in rat kidney. Five pairs of RNA activation sequences targeting the promoter of rat TRPV5 were designed and synthesized. The synthesized saRNA with the strongest activating effect was selected, and transcellular calcium transportation was tested by Fura-2 analysis. Subsequently, Sprague-Dawley rats were equally divided into three groups and fed with water, 1% EG for 28 days after injecting the negative control saRNA, 1% EG for 28 days after injecting the selected TRPV5-saRNA, respectively. The CaOx crystal formation and the 24-h urine components were assessed. In vitro study, saRNA ds-320 could significantly activate the expression of TRPV5 and transcellular calcium transportation. In vivo study, after 28 days treatment of EG, rats pre-infected with saRNA ds-320 had lower urinary calcium excretion and renal CaOx crystals formation as compared to that pre-infected with negative control saRNA. Activation of TRVP5 with saRNA ds-320 could inhibit EG-induced calcium oxalate crystals formation via promoting urine calcium reabsorption and decreasing urine calcium excretion in rats.

Ten-year single-center experience of the ketogenic diet: factors influencing efficacy, tolerability, and compliance.

PubMed

Wibisono, Cinthya; Rowe, Natalie; Beavis, Erin; Kepreotes, Helen; Mackie, Fiona E; Lawson, John A; Cardamone, Michael

2015-04-01

To evaluate the efficacy, tolerability, and compliance of 3 ketogenic diets, the classical ketogenic diet, medium-chain triglyceride (MCT), and modified Atkins diet. A single-center, retrospective study of 48 children with intractable epilepsy receiving ketogenic diets from 2003 to 2012. Patient demographics, epilepsy history, nutritional management, and side effects were collated. Compliance and tolerability were assessed by recording reasons for diet modification and cessation. The value of potassium citrate supplementation for preventing nephrolithiasis was reviewed. Median age at ketogenic diet initiation was 3.8 years (IQR: 2.3-7 years). The majority had intractable epilepsy, and 33 of the 48 children (69%) had epileptic encephalopathies. Three (6%) patients became seizure free, 35 (73%) reported <50%-90% reduction, and 10 (21%) had 0%-50% reduction during a 2-year period. Diet duration or ketogenic diet type did not predict reduction in seizures (P = .381; P = .272). Constipation (n = 31, 65%) was very common. Food refusal (n = 3, 6%) and poor parental compliance (n = 5, 10%) were common reasons cited for cessation. There were lower rates of side effects for modified Atkins diet. Diet cessation was greatest for MCT; however, 3 patients on MCT ceased therapy because adequate seizure control was achieved. Nephrolithiasis was reported in 1 patient before potassium citrate was used and 2 patients noncompliant with potassium citrate supplementation developed hypercalciuria. The 3 ketogenic diets were comparably effective in seizure control and generally well-tolerated. Potassium citrate supplementation is an effective prophylactic supplement for the prevention of nephrolithiasis. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Endocrine Dysfunction in Diamond-Blackfan Anemia (DBA): A Report from the DBA Registry (DBAR).

PubMed

Lahoti, Amit; Harris, Yael T; Speiser, Phyllis W; Atsidaftos, Evangelia; Lipton, Jeffrey M; Vlachos, Adrianna

2016-02-01

Diamond-Blackfan anemia (DBA) is a rare inherited bone marrow failure syndrome. The mainstays of treatment involve chronic red cell transfusions, long-term glucocorticoid therapy, and stem cell transplantation. Systematic data concerning endocrine function in DBA are limited. We studied patients in the DBA Registry (DBAR) of North America to assess the prevalence of various endocrinopathies. In a pilot study, retrospective data were collected for 12 patients with DBA. Subsequently, patients with DBA aged 1-39 years were recruited prospectively. Combined, 57 patients were studied; 38 chronically transfused, 12 glucocorticoid-dependent, and seven in remission. Data were collected on anthropometric measurements, systematic screening of pituitary, thyroid, parathyroid, adrenal, pancreatic, and gonadal function, and ferritin levels. Descriptive statistics were tabulated and group differences were assessed. Fifty-three percent of patients had ≥ 1 endocrine disorder, including adrenal insufficiency (32%), hypogonadism (29%), hypothyroidism (14%), growth hormone dysfunction (7%), diabetes mellitus (2%), and/or diabetes insipidus (2%). Ten of the 33 patients with available heights had height standard deviation less than -2. Low 25-hydroxy vitamin D (25(OH)D) levels were present in 50%. A small proportion also had osteopenia, osteoporosis, or hypercalciuria. Most with adrenal insufficiency were glucocorticoid dependent; other endocrinopathies were more common in chronically transfused patients. Endocrine dysfunction is common in DBA, as early as the teenage years. Although prevalence is highest in transfused patients, patients taking glucocorticoids or in remission also have endocrine dysfunction. Longitudinal studies are needed to better understand the etiology and true prevalence of these disorders. © 2015 Wiley Periodicals, Inc.

Clinical characteristics of chronic kidney disease of non-traditional causes in women of agricultural communities in El Salvador.

PubMed

Herrera Valdés, Raúl; Orantes, Carlos M; Almaguer López, Miguel; López Marín, Laura; Arévalo, Pedro Alfonso; Smith González, Magaly J; Morales, Fabrizio E; Bacallao, Raymed; Bayarre, Héctor D; Vela Parada, Xavier F

2015-01-01

A chronic kidney disease of non-traditional causes (CKDu) has emerged in Central America and elsewhere, predominantly affecting male farmworkers. In El Salvador (2009), it was the second cause of death in men > 18 years old. Causality has not been determined. Most available research focused on men and there is scarce data on women. Describe the clinical and histopathologic characteristics of CKDu in women of agricultural communities in El Salvador. A descriptive study was carried out in 10 women with CKDu stages 2, 3a, and 3b. Researchers studied demographics, clinical examination; hematological and biochemical analyses, urine sediment, renal injury markers, and assessed renal, cardiac, and peripheral arteries, liver, pancreas, and lung anatomy and functions. Kidney biopsy was performed in all. Data was collected on the Lime Survey platform and exported to SPSS 19.0. Patient distribution by stages: 2 (70%), 3a (10%), 3b (20%). Occupation: agricultural 7; non-agricultural 3. agrochemical exposure 100%; farmworkers 70%; incidental malaria 50%, NSAIDs use 40%; hypertension 40%. nocturia 50%; dysuria 50%; arthralgia 70%; asthenia 50%; cramps 30%, profuse sweating 20%. Renal markers: albumin creatinine ratio (ACR) > 300 mg/g 90%; β microglobulin and neutrophil gelatinase- associated lipocalin (NGAL) presence in 40%. Kidney function: hypermagnesuria 100%; hyperphosphaturia 50%, hypercalciuria 40%; hypernatriuria 30%; hyponatremia 60%, hypocalcemia 50%. Doppler: tibial artery damage 40%. Neurological: reflex abnormalities 30%; Babinski and myoclonus 20%. Neurosensorial hypoacusis 70%. Histopathology: damage restricted mostly to the tubulo-interstitium, urine was essentially bland. CKDu in women is a chronic tubulointerstitial nephropathy with varied extrarenal symptoms.

A novel model to explain dietary factors affecting hypocalcaemia in dairy cattle.

PubMed

Martín-Tereso, Javier; Verstegen, Martin W A

2011-12-01

Most dairy cows exhibit different degrees of hypocalcaemia around calving because the gestational Ca requirements shift to the disproportionately high Ca requirements of lactation. Ca homeostasis is a robust system that effectively adapts to changes in Ca demand or supply. However, these adaptations often are not rapid enough to avoid hypocalcaemia. A delay in the reconfiguration of intestinal Ca absorption and bone resorption is probably the underlying cause of this transient hypocalcaemia. Several dietary factors that affect different aspects of Ca metabolism are known to reduce the incidence of milk fever. The present review describes the interactions between nutrition and Ca homeostasis using observations from cattle and extrapolations from other species and aims to quantitatively model the effects of the nutritional approaches that are used to induce dry cows into an early adaptation of Ca metabolism. The present model suggests that reducing dietary cation-anion difference (DCAD) increases Ca clearance from the blood by dietary induction of systemic acidosis, which results in hypercalciuria due to the loss of function of the renal Ca transient receptor potential vanilloid channel TRPV5. Alternatively, reducing the gastrointestinal availability of Ca by reducing dietary Ca or its nutritional availability will also induce the activation of Ca metabolism to compensate for basal blood Ca clearance. Our model of gastrointestinal Ca availability as well as blood Ca clearance in the transition dairy cow allowed us to conclude that the most common dietary strategies for milk fever prevention may have analogous modes of action that are based on the principle of metabolic adaptation before calving.

Type IV neonatal Bartter syndrome complicated with congenital chloride diarrhea.

PubMed

Sakallı, Hale; Bucak, Hakan İbrahim

2012-01-01

Pseudo-Bartter syndrome encompasses a heterogenous group of disorders similar to Bartter syndrome. Sometimes a few status may be nested, as in our case presented here. An 8-month-old boy was referred to our hospital with of intractable diarrhea, polyuria, persistent hypokalemia, abdominal distension and failure to thrive. He was born in the 34 6/7 gestational week (GW) to consanguineous parents. In the 30(th) GW polyhydramnios was verified by ultrasonography. The laboratory results showed hypokalemic-hypochloremic metabolic alkalosis, hyponatremia, and increased urinary loss of chloride, potassium and calcium. An audiogram test revealed complete sensorineural deafness. Ultrasonography revealed medullary nephrocalcinosis in both kidneys. Elevated plasma renin activity and aldosterone were found and a provisional diagnosis of type-IV neonatal Bartter syndrome was made. Treatment with indomethacin, spironolactone and additional intake of NaCl/KCl was initiated. Despite these therapies, the child's diarrhea persisted but serum potassium concentration normalized, and hypercalciuria and urine output reduced. After determining the high fecal chloride concentration, there was an immediate decompensation of the disease on indomethacin withdrawal, thus a diagnosis of type IV neonatal Bartter syndrome complicated with congenital chloride diarrhea was considered. Indomethacin, spironolactone and supplementary therapies with NaCl/KCl were continued, which resulted in the normalization of serum electrolytes as well as his physical development, but high contents of chloride in urine and faeces and nephrocalcinosis remains unchanged during 1-year follow-up. Because of the clinical and laboratory simulations between the various diseases that lead to hypokalemic-hypochloremic metabolic alkalosis, patients must be evaluated carefully.

Type IV neonatal Bartter syndrome complicated with congenital chloride diarrhea

PubMed Central

Sakallı, Hale; Bucak, Hakan İbrahim

2012-01-01

Summary Background: Pseudo-Bartter syndrome encompasses a heterogenous group of disorders similar to Bartter syndrome. Sometimes a few status may be nested, as in our case presented here. Case Report: An 8-month-old boy was referred to our hospital with of intractable diarrhea, polyuria, persistent hypokalemia, abdominal distension and failure to thrive. He was born in the 34 6/7 gestational week (GW) to consanguineous parents. In the 30th GW polyhydramnios was verified by ultrasonography. The laboratory results showed hypokalemic-hypochloremic metabolic alkalosis, hyponatremia, and increased urinary loss of chloride, potassium and calcium. An audiogram test revealed complete sensorineural deafness. Ultrasonography revealed medullary nephrocalcinosis in both kidneys. Elevated plasma renin activity and aldosterone were found and a provisional diagnosis of type-IV neonatal Bartter syndrome was made. Treatment with indomethacin, spironolactone and additional intake of NaCl/KCl was initiated. Despite these therapies, the child’s diarrhea persisted but serum potassium concentration normalized, and hypercalciuria and urine output reduced. After determining the high fecal chloride concentration, there was an immediate decompensation of the disease on indomethacin withdrawal, thus a diagnosis of type IV neonatal Bartter syndrome complicated with congenital chloride diarrhea was considered. Indomethacin, spironolactone and supplementary therapies with NaCl/KCl were continued, which resulted in the normalization of serum electrolytes as well as his physical development, but high contents of chloride in urine and faeces and nephrocalcinosis remains unchanged during 1-year follow-up. Conclusions: Because of the clinical and laboratory simulations between the various diseases that lead to hypokalemic-hypochloremic metabolic alkalosis, patients must be evaluated carefully. PMID:23569535

Dent’s disease: Identification of seven new pathogenic mutations in the CLCN5 gene

PubMed Central

Ramos-Trujillo, Elena; Claverie-Martin, Felix; Garcia-Nieto, Victor; Ariceta, Gema; Vara, Julia; Gonzalez-Acosta, Hilaria; Garcia-Ramirez, Marta; Fons, Jaime; Cordoba-Lanus, Elizabeth; Gonzalez-Paredes, Javier; Valenciano, Blanca; Ramos, Leticia; Muley, Rafael; Caggiani, Marina; Alvarez-Estrada, Pilar; Madrid, Alvaro

2013-01-01

Dent’s disease is an X-linked proximal tubulopathy characterized by low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis and progressive renal failure. This disorder is frequently caused by mutations in the CLCN5 gene encoding the electrogenic chloride/proton exchanger ClC-5. Occasionally, Dent’s disease has been associated to atypical cases of asymptomatic proteinuria with focal glomerulosclerosis. Twelve unrelated patients with Dent’s disease, including two who presented with asymptomatic proteinuria and developed glomerulosclerosis, were studied. Mutational analysis of the CLCN5 gene was performed by DNA sequencing. We identified thirteen distinct CLCN5 mutations in the twelve patients. Seven of these mutations, p.P416fsX*17, p.[H107P, V108fs*27], p.G466D, p.G65R, p.G462S, p.Y164* and c.723+1G >T, were novel and possibly pathogenic. In one family, the patient’s mother was not a carrier of the respective mutation. Our results increased the spectrum of CLCN5 disease causing defects with seven new pathogenic mutations and established a de novo origin in one of them. Remarkably, three new missense mutations, p.G466D, p.G65R and p.G462S, affect highly conserved glycine residues located in transmembrane α-helix GxxxG packing motifs. The two atypical cases further support that the diagnosis of Dent’s disease should be considered in children with asymptomatic proteinuria and focal glomerulosclerosis and without evidence of primary glomerular disease. PMID:27625851

Effect of Potassium Citrate on Calcium Phosphate Stones in a Model of Hypercalciuria

PubMed Central

Asplin, John R.; Frick, Kevin K.; Granja, Ignacio; Culbertson, Christopher D.; Ng, Adeline; Grynpas, Marc D.; Bushinsky, David A.

2015-01-01

Potassium citrate is prescribed to decrease stone recurrence in patients with calcium nephrolithiasis. Citrate binds intestinal and urine calcium and increases urine pH. Citrate, metabolized to bicarbonate, should decrease calcium excretion by reducing bone resorption and increasing renal calcium reabsorption. However, citrate binding to intestinal calcium may increase absorption and renal excretion of both phosphate and oxalate. Thus, the effect of potassium citrate on urine calcium oxalate and calcium phosphate supersaturation and stone formation is complex and difficult to predict. To study the effects of potassium citrate on urine supersaturation and stone formation, we utilized 95th-generation inbred genetic hypercalciuric stone-forming rats. Rats were fed a fixed amount of a normal calcium (1.2%) diet supplemented with potassium citrate or potassium chloride (each 4 mmol/d) for 18 weeks. Urine was collected at 6, 12, and 18 weeks. At 18 weeks, stone formation was visualized by radiography. Urine citrate, phosphate, oxalate, and pH levels were higher and urine calcium level was lower in rats fed potassium citrate. Furthermore, calcium oxalate and calcium phosphate supersaturation were higher with potassium citrate; however, uric acid supersaturation was lower. Both groups had similar numbers of exclusively calcium phosphate stones. Thus, potassium citrate effectively raises urine citrate levels and lowers urine calcium levels; however, the increases in urine pH, oxalate, and phosphate levels lead to increased calcium oxalate and calcium phosphate supersaturation. Potassium citrate induces complex changes in urine chemistries and resultant supersaturation, which may not be beneficial in preventing calcium phosphate stone formation. PMID:25855777

The effect of supplemental oral phosphate on the bone mineral changes during prolonged bed rest

PubMed Central

Hulley, Stephen B.; Vogel, John M.; Donaldson, Charles L.; Bayers, Jon H.; Friedman, Ronald J.; Rosen, Sheldon N.

1971-01-01

Five healthy young men were studied during 24-30 wk of continuous bed rest. During the first 12 wk of bed rest, untreated subjects increased calcium excretion in the urine by 109 mg/day and in the feces by 147 mg/day. The rate of total body calcium loss was 0.5-0.7% per month. Losses of central calcaneus mineral, assessed by gamma ray transmission scanning, occurred at a tenfold higher rate, whereas the mineral content of the radius did not change. Changes in phosphorus balance resembled the calcium pattern, and increased excretion of nitrogen and hydroxyproline also occurred during bed rest. Upon reambulation, the subjects' calcium balance became positive in 1 month and recovery of their calcaneus mineral was complete within 10-20 wk. Treatment with potassium phosphate supplements (1327 mg P/day) entirely prevented the hypercalciuria of bed rest, but fecal calcium tended to increase. During the first 12 wk, calcium balance was slightly less negative (mean - 193 mg/day) than during bed rest without added phosphate (mean - 267 mg/day). This effect was not seen during the second 12 wk of bed rest. The patterns of magnesium excretion were similar to those of calcium. Fecal and urinary phosphorus excretions were doubled, and phosphorus balance became positive (+ 113 mg/day). Mineral loss from the central calcaneus was similar to that of untreated subjects. It is concluded that this form of phosphate supplementation reduces urinary calcium excretion but does not prevent bone loss during bed rest. PMID:5129304

Nocturnal polyuria is related to absent circadian rhythm of glomerular filtration rate.

PubMed

De Guchtenaere, A; Vande Walle, C; Van Sintjan, P; Raes, A; Donckerwolcke, R; Van Laecke, E; Hoebeke, P; Vande Walle, J

2007-12-01

Monosymptomatic nocturnal enuresis is frequently associated with nocturnal polyuria and low urinary osmolality during the night. Initial studies found decreased vasopressin levels associated with low urinary osmolality overnight. Together with the documented desmopressin response, this was suggestive of a primary role for vasopressin in the pathogenesis of enuresis in the absence of bladder dysfunction. Recent studies no longer confirm this primary role of vasopressin. Other pathogenetic factors such as disordered renal sodium handling, hypercalciuria, increased prostaglandins and/or osmotic excretion might have a role. So far, little attention has been given to abnormalities in the circadian rhythm of glomerular filtration rate. We evaluated the circadian rhythm of glomerular filtration rate and diuresis in children with desmopressin resistant monosymptomatic nocturnal enuresis and nocturnal polyuria. We evaluated 15 children (9 boys) 9 to 14 years old with monosymptomatic nocturnal enuresis and nocturnal polyuria resistant to desmopressin treatment. The control group consisted of 25 children (12 boys) 9 to 16 years old with monosymptomatic nocturnal enuresis without nocturnal polyuria. Compared to the control population, children with nocturnal polyuria lost their circadian rhythm not only for diuresis and sodium excretion but also for glomerular filtration rate. Patients with monosymptomatic nocturnal enuresis and nocturnal polyuria lack a normal circadian rhythm for diuresis and sodium excretion, and the circadian rhythm of glomerular filtration rate is absent. This absence of circadian rhythm of glomerular filtration rate and/or sodium handling cannot be explained by a primary role of vasopressin, but rather by a disorder in circadian rhythm of renal glomerular and/or tubular functions.

The Calcium-Sensing Receptor in Health and Disease.

PubMed

Díaz-Soto, G; Rocher, A; García-Rodríguez, C; Núñez, L; Villalobos, C

2016-01-01

The extracellular calcium-sensing receptor (CaSR) is a unique G protein-coupled receptor (GPCR) activated by extracellular Ca 2+ and by other physiological cations including Mg 2+ , amino acids, and polyamines. CaSR is the most important master controller of the extracellular Ca 2+ homeostatic system being expressed at high levels in the parathyroid gland, kidney, gut and bone, where it regulates parathyroid hormone (PTH) secretion, vitamin D synthesis, and Ca 2+ absorption and resorption, respectively. Gain and loss of function mutations in the CaSR are responsible for severe disturbances in extracellular Ca 2+ metabolism. CaSR agonists (calcimimetics) and antagonists (calcilytics) are in use or under intense research for treatment of hyperparathyroidism secondary to kidney failure and hypocalcemia with hypercalciuria, respectively. Expression of the CaSR extends to other tissues and systems beyond the extracellular Ca 2+ homeostatic system including the cardiovascular system, the airways, and the nervous system where it may play physiological functions yet to be fully understood. As a consequence, CaSR has been recently involved in different pathologies including uncontrolled blood pressure, vascular calcification, asthma, and Alzheimer's disease. Finally, the CaSR has been shown to play a critical role in cancer either contributing to bone metastasis and/or acting as a tumor suppressor in some forms of cancer (parathyroid cancer, colon cancer, and neuroblastoma) and as oncogene in others (breast and prostate cancers). Here we review the role of CaSR in health and disease in calciotropic tissues and others beyond the extracellular calcium homeostatic system. Copyright © 2016 Elsevier Inc. All rights reserved.

Hypocalcemia

PubMed Central

Fong, Jeremy; Khan, Aliya

2012-01-01

Abstract Objective To provide family physicians with an evidence-based approach to the diagnosis and management of hypocalcemia. Quality of evidence MEDLINE and EMBASE articles from 2000 to 2010 were searched, with a focus on the diagnosis and management of hypocalcemia. Levels of evidence (I to III) were cited where appropriate, with most studies providing level II or III evidence. References of pertinent papers were also searched for relevant articles. Main message Chronic hypocalcemia is commonly due to inadequate levels of parathyroid hormone or vitamin D, or due to resistance to these hormones. Treatment focuses on oral calcium and vitamin D supplements, as well as magnesium if deficiency is present. Treatment can be further intensified with thiazide diuretics, phosphate binders, and a low-salt and low-phosphorus diet when treating hypocalcemia secondary to hypoparathyroidism. Acute and life-threatening calcium deficit requires treatment with intravenous calcium. The current treatment recommendations are largely based on expert clinical opinion and published case reports, as adequately controlled clinical trial data are not currently available. Complications of current therapies for hypoparathyroidism include hypercalciuria, nephrocalcinosis, renal impairment, and soft tissue calcification. Current therapy is limited by serum calcium fluctuations. Although these complications are well recognized, the effects of therapy on overall well-being, mood, cognition, and quality of life, as well as the risk of complications, have not been adequately studied. Conclusion Family physicians play a crucial role in educating patients about the long-term management and complications of hypocalcemia. Currently, management is suboptimal and marked by fluctuations in serum calcium and a lack of approved parathyroid hormone replacement therapy for hypoparathyroidism. PMID:22439169

Autosomal dominant hypoparathyroidism caused by germline mutation in GNA11: phenotypic and molecular characterization.

PubMed

Li, Dong; Opas, Evan E; Tuluc, Florin; Metzger, Daniel L; Hou, Cuiping; Hakonarson, Hakon; Levine, Michael A

2014-09-01

Most cases of autosomal dominant hypoparathyroidism (ADH) are caused by gain-of-function mutations in CASR or dominant inhibitor mutations in GCM2 or PTH. Our objectives were to identify the genetic basis for ADH in a multigenerational family and define the underlying disease mechanism. Here we evaluated a multigenerational family with ADH in which affected subjects had normal sequences in these genes and were shorter than unaffected family members. We collected clinical and biochemical data from 6 of 11 affected subjects and performed whole-exome sequence analysis on DNA from two affected sisters and their affected father. Functional studies were performed after expression of wild-type and mutant Gα11 proteins in human embryonic kidney-293-CaR cells that stably express calcium-sensing receptors. Whole-exome-sequencing followed by Sanger sequencing revealed a heterozygous mutation, c.179G>T; p.R60L, in GNA11, which encodes the α-subunit of G11, the principal heterotrimeric G protein that couples calcium-sensing receptors to signal activation in parathyroid cells. Functional studies of Gα11 R60L showed increased accumulation of intracellular concentration of free calcium in response to extracellular concentration of free calcium with a significantly decreased EC50 compared with wild-type Gα11. By contrast, R60L was significantly less effective than the oncogenic Q209L form of Gα11 as an activator of the MAPK pathway. Compared to subjects with CASR mutations, patients with GNA11 mutations lacked hypercalciuria and had normal serum magnesium levels. Our findings indicate that the germline gain-of-function mutation of GNA11 is a cause of ADH and implicate a novel role for GNA11 in skeletal growth.

Autosomal Dominant Hypoparathyroidism Caused by Germline Mutation in GNA11: Phenotypic and Molecular Characterization

PubMed Central

Li, Dong; Opas, Evan E.; Tuluc, Florin; Metzger, Daniel L.; Hou, Cuiping; Hakonarson, Hakon

2014-01-01

Context: Most cases of autosomal dominant hypoparathyroidism (ADH) are caused by gain-of-function mutations in CASR or dominant inhibitor mutations in GCM2 or PTH. Objective: Our objectives were to identify the genetic basis for ADH in a multigenerational family and define the underlying disease mechanism. Subjects: Here we evaluated a multigenerational family with ADH in which affected subjects had normal sequences in these genes and were shorter than unaffected family members. Methods: We collected clinical and biochemical data from 6 of 11 affected subjects and performed whole-exome sequence analysis on DNA from two affected sisters and their affected father. Functional studies were performed after expression of wild-type and mutant Gα11 proteins in human embryonic kidney-293-CaR cells that stably express calcium-sensing receptors. Results: Whole-exome-sequencing followed by Sanger sequencing revealed a heterozygous mutation, c.179G>T; p.R60L, in GNA11, which encodes the α-subunit of G11, the principal heterotrimeric G protein that couples calcium-sensing receptors to signal activation in parathyroid cells. Functional studies of Gα11 R60L showed increased accumulation of intracellular concentration of free calcium in response to extracellular concentration of free calcium with a significantly decreased EC50 compared with wild-type Gα11. By contrast, R60L was significantly less effective than the oncogenic Q209L form of Gα11 as an activator of the MAPK pathway. Compared to subjects with CASR mutations, patients with GNA11 mutations lacked hypercalciuria and had normal serum magnesium levels. Conclusions: Our findings indicate that the germline gain-of-function mutation of GNA11 is a cause of ADH and implicate a novel role for GNA11 in skeletal growth. PMID:24823460

Amino Alcohol- (NPS-2143) and Quinazolinone-Derived Calcilytics (ATF936 and AXT914) Differentially Mitigate Excessive Signalling of Calcium-Sensing Receptor Mutants Causing Bartter Syndrome Type 5 and Autosomal Dominant Hypocalcemia

PubMed Central

Letz, Saskia; Haag, Christine; Schulze, Egbert; Frank-Raue, Karin; Raue, Friedhelm; Hofner, Benjamin; Mayr, Bernhard; Schöfl, Christof

2014-01-01

Introduction Activating calcium sensing receptor (CaSR) mutations cause autosomal dominant hypocalcemia (ADH) characterized by low serum calcium, inappropriately low PTH and relative hypercalciuria. Four activating CaSR mutations cause additional renal wasting of sodium, chloride and other salts, a condition called Bartter syndrome (BS) type 5. Until today there is no specific medical treatment for BS type 5 and ADH. We investigated the effects of different allosteric CaSR antagonists (calcilytics) on activating CaSR mutants. Methods All 4 known mutations causing BS type 5 and five ADH mutations were expressed in HEK 293T cells and receptor signalling was studied by measurement of intracellular free calcium in response to extracellular calcium ([Ca2+]o). To investigate the effect of calcilytics, cells were stimulated with 3 mM [Ca2+]o in the presence or absence of NPS-2143, ATF936 or AXT914. Results All BS type 5 and ADH mutants showed enhanced signalling activity to [Ca2+]o with left shifted dose response curves. In contrast to the amino alcohol NPS-2143, which was only partially effective, the quinazolinone calcilytics ATF936 and AXT914 significantly mitigated excessive cytosolic calcium signalling of all BS type 5 and ADH mutants studied. When these mutants were co-expressed with wild-type CaSR to approximate heterozygosity in patients, ATF936 and AXT914 were also effective on all mutants. Conclusion The calcilytics ATF936 and AXT914 are capable of attenuating enhanced cytosolic calcium signalling activity of CaSR mutations causing BS type 5 and ADH. Quinazolinone calcilytics might therefore offer a novel treatment option for patients with activating CaSR mutations. PMID:25506941

Derangement of calcium metabolism in diabetes mellitus: negative outcome from the synergy between impaired bone turnover and intestinal calcium absorption.

PubMed

Wongdee, Kannikar; Krishnamra, Nateetip; Charoenphandhu, Narattaphol

2017-01-01

Both types 1 and 2 diabetes mellitus (T1DM and T2DM) are associated with profound deterioration of calcium and bone metabolism, partly from impaired intestinal calcium absorption, leading to a reduction in calcium uptake into the body. T1DM is associated with low bone mineral density (BMD) and osteoporosis, whereas the skeletal changes in T2DM are variable, ranging from normal to increased and to decreased BMD. However, both types of DM eventually compromise bone quality through production of advanced glycation end products and misalignment of collagen fibrils (so-called matrix failure), thereby culminating in a reduction of bone strength. The underlying cellular mechanisms (cellular failure) are related to suppression of osteoblast-induced bone formation and bone calcium accretion, as well as to enhancement of osteoclast-induced bone resorption. Several other T2DM-related pathophysiological changes, e.g., osteoblast insulin resistance, impaired productions of osteogenic growth factors (particularly insulin-like growth factor 1 and bone morphogenetic proteins), overproduction of pro-inflammatory cytokines, hyperglycemia, and dyslipidemia, also aggravate diabetic osteopathy. In the kidney, DM and the resultant hyperglycemia lead to calciuresis and hypercalciuria in both humans and rodents. Furthermore, DM causes deranged functions of endocrine factors related to mineral metabolism, e.g., parathyroid hormone, 1,25-dihydroxyvitamin D 3 , and fibroblast growth factor-23. Despite the wealth of information regarding impaired bone remodeling in DM, the long-lasting effects of DM on calcium metabolism in young growing individuals, pregnant women, and neonates born to women with gestational DM have received scant attention, and their underlying mechanisms are almost unknown and worth exploring.

Fluid and Electrolyte Nutrition

NASA Technical Reports Server (NTRS)

Lane, Helen W.; Smith, Scott M.; Leach, Carolyn S.; Rice, Barbara L.

1999-01-01

Studies of fluid and electrolyte homeostasis have been completed since the early human space flight programs, with comprehensive research completed on the Spacelab Life Sciences missions SLS-1 and SLS-2 flights, and more recently on the Mir 18 mission. This work documented the known shifts in fluids, the decrease in total blood volume, and indications of reduced thirst. Data from these flights was used to evaluate the nutritional needs for water, sodium, and potassium. Interpretations of the data are confounded by the inadequate energy intakes routinely observed during space flight. This in turn results in reduced fluid intake, as food provides approximately 70% water intake. Subsequently, body weight, lean body mass, total body water, and total body potassium may decrease. Given these issues, there is evidence to support a minimum required water intake of 2 L per day. Data from previous Shuttle flights indicated that water intake is 2285 +/- 715 ml/day (mean +/- SD, n=26). There are no indications that sodium intake or homeostasis is compromised during space flight. The normal or low aldosterone and urinary sodium levels suggest adequate sodium intake (4047 +/- 902 mg/day, n=26). Because excessive sodium intake is associated with hypercalciuria, the recommended maximum amount of sodium intake during flight is 3500 mg/day (i.e., similar to the Recommended Dietary Allowance, RDA). Potassium metabolism appears to be more complex. Data indicate loss of body potassium related to muscle atrophy and low dietary intake (2407 +/- 548 mg/day, n=26). Although possibly related to measurement error, the elevations in blood potassium suggest alterations in potassium homeostasis. The space RDA for minimum potassium intake is 3500 mg/day. With the documented inadequate intakes, efforts are being made to increase dietary consumption of potassium.

Management of male osteoporosis.

PubMed

Cortet, B; Vasseur, J; Grardel, B; Catanzariti, L; Marchandise, X; Delcambre, B

2001-05-01

The objective of this study was to evaluate the efficacy of treatments for male osteoporosis selected based on the cause of the disease. Sixty-three men with osteoporosis (T-score at the lumbar spine and/or femoral neck lower than -2.5) with a mean age of 53+/-11 years were studied. Forty-three (68.3%) had a history of fracturing without trauma (vertebral fractures, 37 patients, 57%). Treatments were as follows: idiopathic osteoporosis: calcium and vitamin D supplements (N = 10) or cyclical etidronate for 2 weeks followed by calcium and vitamin D supplements for 76 days (N = 29); moderate idiopathic phosphate diabetes: calcitriol and phosphate (N = 15); idiopathic hypercalciuria: hydrochlorothiazide (N = 6); and hypogonadism: testosterone (N = 3). Percentage change in bone mineral density (mean +/- standard error of the mean) after 18 months: calcium and vitamin D (lumbar spine: 0.6+/-2; femoral neck: 2.2+/-2.2); etidronate (lumbar spine: 3.6+/-1.4*; femoral neck: 0.5+/-1); calcitriol (lumbar spine: 7.0+/-3.5*; femoral neck: 0.0+/-1.4); thiazide diuretic (lumbar spine: 1+/-3.2; femoral neck: -2.3+/-3.7); and testosterone (lumbar spine: 6.8+/-6.4; femoral neck: 2.5+/-2.7), where *P < 0.05 versus baseline. Gastrointestinal side effects occurred in three patients (4.8%), including two on calcitriol-phosphate therapy and one on etidronate therapy. Of the six (9.5%) patients who experienced incident fractures, four were on etidronate, one on calcitriol-phosphate, and one on calcium-vitamin D. No patients discontinued their treatment because of side effects. Etidronate and the combination of calcitriol-phosphate produce a significant increase in lumbar spine bone mass in men with idiopathic osteoporosis or moderate idiopathic phosphate diabetes.

Clinical and Genetic Spectrum of Bartter Syndrome Type 3.

PubMed

Seys, Elsa; Andrini, Olga; Keck, Mathilde; Mansour-Hendili, Lamisse; Courand, Pierre-Yves; Simian, Christophe; Deschenes, Georges; Kwon, Theresa; Bertholet-Thomas, Aurélia; Bobrie, Guillaume; Borde, Jean Sébastien; Bourdat-Michel, Guylhène; Decramer, Stéphane; Cailliez, Mathilde; Krug, Pauline; Cozette, Paul; Delbet, Jean Daniel; Dubourg, Laurence; Chaveau, Dominique; Fila, Marc; Jourde-Chiche, Noémie; Knebelmann, Bertrand; Lavocat, Marie-Pierre; Lemoine, Sandrine; Djeddi, Djamal; Llanas, Brigitte; Louillet, Ferielle; Merieau, Elodie; Mileva, Maria; Mota-Vieira, Luisa; Mousson, Christiane; Nobili, François; Novo, Robert; Roussey-Kesler, Gwenaëlle; Vrillon, Isabelle; Walsh, Stephen B; Teulon, Jacques; Blanchard, Anne; Vargas-Poussou, Rosa

2017-08-01

Bartter syndrome type 3 is a clinically heterogeneous hereditary salt-losing tubulopathy caused by mutations of the chloride voltage-gated channel Kb gene ( CLCNKB ), which encodes the ClC-Kb chloride channel involved in NaCl reabsorption in the renal tubule. To study phenotype/genotype correlations, we performed genetic analyses by direct sequencing and multiplex ligation-dependent probe amplification and retrospectively analyzed medical charts for 115 patients with CLCNKB mutations. Functional analyses were performed in Xenopus laevis oocytes for eight missense and two nonsense mutations. We detected 60 mutations, including 27 previously unreported mutations. Among patients, 29.5% had a phenotype of ante/neonatal Bartter syndrome (polyhydramnios or diagnosis in the first month of life), 44.5% had classic Bartter syndrome (diagnosis during childhood, hypercalciuria, and/or polyuria), and 26.0% had Gitelman-like syndrome (fortuitous discovery of hypokalemia with hypomagnesemia and/or hypocalciuria in childhood or adulthood). Nine of the ten mutations expressed in vitro decreased or abolished chloride conductance. Severe (large deletions, frameshift, nonsense, and essential splicing) and missense mutations resulting in poor residual conductance were associated with younger age at diagnosis. Electrolyte supplements and indomethacin were used frequently to induce catch-up growth, with few adverse effects. After a median follow-up of 8 (range, 1-41) years in 77 patients, chronic renal failure was detected in 19 patients (25%): one required hemodialysis and four underwent renal transplant. In summary, we report a genotype/phenotype correlation for Bartter syndrome type 3: complete loss-of-function mutations associated with younger age at diagnosis, and CKD was observed in all phenotypes. Copyright © 2017 by the American Society of Nephrology.

Poor phenotype-genotype association in a large series of patients with Type III Bartter syndrome.

PubMed

García Castaño, Alejandro; Pérez de Nanclares, Gustavo; Madariaga, Leire; Aguirre, Mireia; Madrid, Álvaro; Chocrón, Sara; Nadal, Inmaculada; Navarro, Mercedes; Lucas, Elena; Fijo, Julia; Espino, Mar; Espitaletta, Zilac; García Nieto, Víctor; Barajas de Frutos, David; Loza, Reyner; Pintos, Guillem; Castaño, Luis; Ariceta, Gema

2017-01-01

Type III Bartter syndrome (BS) is an autosomal recessive renal tubule disorder caused by loss-of-function mutations in the CLCNKB gene, which encodes the chloride channel protein ClC-Kb. In this study, we carried out a complete clinical and genetic characterization in a cohort of 30 patients, one of the largest series described. By comparing with other published populations, and considering that 80% of our patients presented the p.Ala204Thr Spanish founder mutation presumably associated with a common phenotype, we aimed to test the hypothesis that allelic differences could explain the wide phenotypic variability observed in patients with type III BS. Clinical data were retrieved from the referral centers. The exon regions and flanking intronic sequences of the CLCNKB gene were screened for mutations by polymerase chain reaction (PCR) followed by direct Sanger sequencing. Presence of gross deletions or duplications in the region was checked for by MLPA and QMPSF analyses. Polyuria, polydipsia and dehydration were the main common symptoms. Metabolic alkalosis and hypokalemia of renal origin were detected in all patients at diagnosis. Calciuria levels were variable: hypercalciuria was detected in 31% of patients, while 23% had hypocalciuria. Nephrocalcinosis was diagnosed in 20% of the cohort. Two novel CLCNKB mutations were identified: a small homozygous deletion (c.753delG) in one patient and a small deletion (c.1026delC) in another. The latter was present in compound heterozygosis with the already previously described p.Glu442Gly mutation. No phenotypic association was obtained regarding the genotype. A poor correlation was found between a specific type of mutation in the CLCNKB gene and type III BS phenotype. Importantly, two CLCNKB mutations not previously described were found in our cohort.

Hypokalemic paralysis in a middle-aged female with classic Bartter syndrome.

PubMed

Chiang, Wen-Fang; Lin, Shih-Hung; Chan, Jenq-Shyong; Lin, Shih-Hua

2014-02-01

Inherited classic Bartter syndrome (cBS) is an autosomal recessive renal tubular disorder resulting from inactivating mutations in the asolateral chloride channel (C1C-Kb) and usually presents in early infancy or childhood with mild to moderate hypokalemia. Profound hypokalemic paralysis in patients with cBS is extremely rare, especially in middle age. A 45-year-old Chinese female patient was referred for evaluation of chronic severe hypokalemia despite regular K+ supplementation (1 mmol/kg/d). She had had two episodes of muscle paralysis due to severe hypokalemia (K+ 1.9 - 2.1 mmol/l) in the past 3 years. She denied vomiting, diarrhea, or the use of laxatives or diuretics. Her blood pressure was normal. Biochemical studies showed hypokalemia (K+ 2.5 mmol/l) with renal potassium wasting, metabolic alkalosis (HCO3- 32 mmol/l), normomagnesemia (Mg2+ 0.8 mmol/l), hypercalciuria (calcium to creatinine ratio 0.5 mmol/mmol; normal < 0.22 mmol/mol), high plasma renin activity, but normal plasma aldosterone concentration. Abdominal sonography revealed neither renal stones nor nephrocalcinosis. Acquired causes of cBS such as autoimmune disease and drugs were all excluded. Molecular analysis of the CLCNKB gene, encoding ClC-Kb, and SLC12A3, encoding the thiazide-sensitive sodium chloride cotransporter (NCC), revealed compound heterozygous mutations in CLCNKB (L335P and G470E) inherited from her parents; her SLC12A3 was normal. These two mutations were not identified in 100 healthy subjects. Her plasma K+ concentration rose to 3 - 3.5 mmol/l after the addition of spironolactone. Inherited cBS may present with hypokalemic paralysis and should be considered in adult patients with hypokalemia and metabolic alkalosis.

Evaluation of a 12-week targeted vitamin D supplementation regimen in patients with active inflammatory bowel disease.

PubMed

Garg, Mayur; Rosella, Ourania; Rosella, Gennaro; Wu, Yunqiu; Lubel, John S; Gibson, Peter R

2017-06-15

Vitamin D at serum 25(OH)D concentrations above 100 nmol/L is associated with disease remission in patients with IBD, suggesting targeted dosing might be anti-inflammatory. This study aimed to assess the effectiveness, safety and predictors of a 12-week regimen of vitamin D supplementation to achieve such a target in patients with active disease. In a pilot study, patients with active colitis and a serum 25(OH)D concentration <75 nmol/L were prescribed oral liquid vitamin D supplementation over 12 weeks using a specific protocol with dose adjusted 4-weekly to aim for a target level of 100-125 nmol/L. Five patients each with Crohn's colitis or ulcerative colitis (UC) had mean 25(OH)D concentration 52 (range 27-73 nmol/L). Five reached the targeted level and four 89-95 nmol/L. One withdrew after 4 weeks (88 nmol/L). Target dose was met only in those with BMI <30 kg/m 2 and total dose inversely correlated with initial serum 25(OH)D. One patient had developed a high level at 8 weeks (146 nmol/L) and another new hypercalciuria. There were no serious adverse events attributable to the therapy. Clinical disease activity consistently declined, but faecal calprotectin and circulating markers of inflammation did not. A specified oral vitamin D regimen successfully and safely achieved target or near-target levels, improved symptom-based activity scores, but did not alter objective measures of intestinal or systemic inflammation. A modified version of this dose-escalating regimen would be suitable for a randomised placebo-controlled trial, but does require regular safety monitoring. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

FGF23 AND SYNDROMES OF ABNORMAL RENAL PHOSPHATE HANDLING

PubMed Central

Bergwitz, Clemens; Jüppner, Harald

2016-01-01

Fibroblast growth factor 23 (FGF23) is part of a previously unrecognized hormonal bone-parathyroid-kidney axis, which is modulated by 1,25(OH)2-vitamin D (1,25(OH)2D), dietary and circulating phosphate and possibly PTH. FGF23 was discovered as the humoral factor in tumors that causes hypophosphatemia and osteomalacia and through the identification of a mutant form of FGF23 that leads to autosomal dominant hypophosphatemic rickets (ADHR), a rare genetic disorder. FGF23 appears to be mainly secreted by osteocytes where its expression is up-regulated by 1,25(OH)2D and probably by increased serum phosphate levels. Its synthesis and secretion is reduced through yet unknown mechanisms that involve the phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PHEX), dentin matrix protein 1 (DMP1) and ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1). Consequently, loss-of-function mutations in these genes underlie hypophosphatemic disorders that are either X-linked or autosomal recessive. Impaired O-glycosylation of FGF23 due to the lack of UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyl-transferase 3 (GALNT3) or due to certain homozygous FGF23 mutations results in reduced secretion of intact FGF23 and leads to familial hypophosphatemic tumoral calcinosis. FGF23 acts through FGF-receptors and the coreceptor Klotho to reduce 1,25(OH)2D synthesis in the kidney and probably the synthesis of parathyroid hormone (PTH) by the parathyroid glands. It furthermore synergizes with PTH to increase renal phosphate excretion by reducing expression of the sodium-phosphate cotransporters NaPi-IIa and NaPi-IIc in the proximal tubules. Loss-of-function mutations in these two transporters lead to autosomal recessive Fanconi syndrome or to hereditary hypophosphatemic rickets with hypercalciuria, respectively. PMID:22396161

Poor phenotype-genotype association in a large series of patients with Type III Bartter syndrome

PubMed Central

Pérez de Nanclares, Gustavo; Madariaga, Leire; Aguirre, Mireia; Madrid, Álvaro; Chocrón, Sara; Nadal, Inmaculada; Navarro, Mercedes; Lucas, Elena; Fijo, Julia; Espino, Mar; Espitaletta, Zilac; García Nieto, Víctor; Barajas de Frutos, David; Loza, Reyner; Pintos, Guillem; Castaño, Luis; Ariceta, Gema

2017-01-01

Introduction Type III Bartter syndrome (BS) is an autosomal recessive renal tubule disorder caused by loss-of-function mutations in the CLCNKB gene, which encodes the chloride channel protein ClC-Kb. In this study, we carried out a complete clinical and genetic characterization in a cohort of 30 patients, one of the largest series described. By comparing with other published populations, and considering that 80% of our patients presented the p.Ala204Thr Spanish founder mutation presumably associated with a common phenotype, we aimed to test the hypothesis that allelic differences could explain the wide phenotypic variability observed in patients with type III BS. Methods Clinical data were retrieved from the referral centers. The exon regions and flanking intronic sequences of the CLCNKB gene were screened for mutations by polymerase chain reaction (PCR) followed by direct Sanger sequencing. Presence of gross deletions or duplications in the region was checked for by MLPA and QMPSF analyses. Results Polyuria, polydipsia and dehydration were the main common symptoms. Metabolic alkalosis and hypokalemia of renal origin were detected in all patients at diagnosis. Calciuria levels were variable: hypercalciuria was detected in 31% of patients, while 23% had hypocalciuria. Nephrocalcinosis was diagnosed in 20% of the cohort. Two novel CLCNKB mutations were identified: a small homozygous deletion (c.753delG) in one patient and a small deletion (c.1026delC) in another. The latter was present in compound heterozygosis with the already previously described p.Glu442Gly mutation. No phenotypic association was obtained regarding the genotype. Conclusion A poor correlation was found between a specific type of mutation in the CLCNKB gene and type III BS phenotype. Importantly, two CLCNKB mutations not previously described were found in our cohort. PMID:28288174

Evaluation of vitamin D3 intakes up to 15,000 international units/day and serum 25-hydroxyvitamin D concentrations up to 300 nmol/L on calcium metabolism in a community setting.

PubMed

Kimball, S M; Mirhosseini, N; Holick, M F

2017-01-01

Supplementation by the general public with vitamin D at doses above the Tolerable Upper Level of Intake (UL) is becoming quite common. The objective of the current analysis was to characterize the effect of vitamin D supplementation at doses up to 15,000 IU/d in a community-based program on vitamin D status, calcium homeostasis as well as on kidney, liver and immune function. We evaluated data collected for 3,882 participants in a community program for whom there were blood measurements at program entry and at follow-up within 6-18 months between 2013 and 2015. Participants were supplemented with a wide range of vitamin D doses (1,000 - 15,000 IU/d) aimed at achieving serum 25-hydroxyvitamin D [25(OH)D] levels of at least 100 nmol/L. Serum 25(OH)D concentrations up to 300 nmol/L were achieved without perturbation of calcium homeostasis or incidence of toxicity. Hypercalcemia and hypercalciuria were not related to an increase in 25(OH)D concentrations nor vitamin D dose. To achieve serum 25(OH)D levels >100 nmol/L on average, required vitamin D intakes of 6,000 IU/d for normal Body Mass Index (BMI), 7,000 IU/d for overweight and 8,000 IU/d for obese. Doses of vitamin D in excess of 6,000 IU/d were required to achieve serum 25(OH)D concentrations above 100 nmol/L, especially in individuals who were overweight or obese without any evidence of toxicity. Serum 25(OH)D concentrations up to 300 nmol/L were found to be safe.

Amino acid supplementation alters bone metabolism during simulated weightlessness

NASA Technical Reports Server (NTRS)

Zwart, S. R.; Davis-Street, J. E.; Paddon-Jones, D.; Ferrando, A. A.; Wolfe, R. R.; Smith, S. M.

2005-01-01

High-protein and acidogenic diets induce hypercalciuria. Foods or supplements with excess sulfur-containing amino acids increase endogenous sulfuric acid production and therefore have the potential to increase calcium excretion and alter bone metabolism. In this study, effects of an amino acid/carbohydrate supplement on bone resorption were examined during bed rest. Thirteen subjects were divided at random into two groups: a control group (Con, n = 6) and an amino acid-supplemented group (AA, n = 7) who consumed an extra 49.5 g essential amino acids and 90 g carbohydrate per day for 28 days. Urine was collected for n-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and pH determinations. Bone mineral content was determined and potential renal acid load was calculated. Bone-specific alkaline phosphatase was measured in serum samples collected on day 1 (immediately before bed rest) and on day 28. Potential renal acid load was higher in the AA group than in the Con group during bed rest (P < 0.05). For all subjects, during bed rest urinary NTX and DPD concentrations were greater than pre-bed rest levels (P < 0.05). Urinary NTX and DPD tended to be higher in the AA group (P = 0.073 and P = 0.056, respectively). During bed rest, urinary calcium was greater than baseline levels (P < 0.05) in the AA group but not the Con group. Total bone mineral content was lower after bed rest than before bed rest in the AA group but not the Con group (P < 0.05). During bed rest, urinary pH decreased (P < 0.05), and it was lower in the AA group than the Con group. These data suggest that bone resorption increased, without changes in bone formation, in the AA group.

Deficiency of Carbonic Anhydrase II Results in a Urinary Concentrating Defect

PubMed Central

Krishnan, Devishree; Pan, Wanling; Beggs, Megan R.; Trepiccione, Francesco; Chambrey, Régine; Eladari, Dominique; Cordat, Emmanuelle; Dimke, Henrik; Alexander, R. Todd

2018-01-01

Carbonic anhydrase II (CAII) is expressed along the nephron where it interacts with a number of transport proteins augmenting their activity. Aquaporin-1 (AQP1) interacts with CAII to increase water flux through the water channel. Both CAII and aquaporin-1 are expressed in the thin descending limb (TDL); however, the physiological role of a CAII-AQP1 interaction in this nephron segment is not known. To determine if CAII was required for urinary concentration, we studied water handling in CAII-deficient mice. CAII-deficient mice demonstrate polyuria and polydipsia as well as an alkaline urine and bicarbonaturia, consistent with a type III renal tubular acidosis. Natriuresis and hypercalciuria cause polyuria, however, CAII-deficient mice did not have increased urinary sodium nor calcium excretion. Further examination revealed dilute urine in the CAII-deficient mice. Urinary concentration remained reduced in CAII-deficient mice relative to wild-type animals even after water deprivation. The renal expression and localization by light microscopy of NKCC2 and aquaporin-2 was not altered. However, CAII-deficient mice had increased renal AQP1 expression. CAII associates with and increases water flux through aquaporin-1. Water flux through aquaporin-1 in the TDL of the loop of Henle is essential to the concentration of urine, as this is required to generate a concentrated medullary interstitium. We therefore measured cortical and medullary interstitial concentration in wild-type and CAII-deficient mice. Mice lacking CAII had equivalent cortical interstitial osmolarity to wild-type mice: however, they had reduced medullary interstitial osmolarity. We propose therefore that reduced water flux through aquaporin-1 in the TDL in the absence of CAII prevents the generation of a maximally concentrated medullary interstitium. This, in turn, limits urinary concentration in CAII deficient mice. PMID:29354070

Biallelic mutations in CYP24A1 or SLC34A1 as a cause of infantile idiopathic hypercalcemia (IIH) with vitamin D hypersensitivity: molecular study of 11 historical IIH cases.

PubMed

Pronicka, Ewa; Ciara, Elżbieta; Halat, Paulina; Janiec, Agnieszka; Wójcik, Marek; Rowińska, Elżbieta; Rokicki, Dariusz; Płudowski, Paweł; Wojciechowska, Ewa; Wierzbicka, Aldona; Książyk, Janusz B; Jacoszek, Agnieszka; Konrad, Martin; Schlingmann, Karl P; Litwin, Mieczysław

2017-08-01

Idiopathic infantile hypercalcemia (IIH) is a mineral metabolism disorder characterized by severe hypercalcemia, failure to thrive, vomiting, dehydration, and nephrocalcinosis. The periodical increase in incidence of IIH, which occurred in the twentieth century in the United Kingdom, Poland, and West Germany, turned out to be a side effect of rickets over-prophylaxis. It was recently discovered that the condition is linked to two genes, CYP24A1 and SLC34A1. The aim of the study was to search for pathogenic variants of the genes in adult persons who were shortlisted in infancy as IIH caused by "hypersensitivity to vit. D". All persons were found to carry mutations in CYP24A1 or SLC34A1, nine and two persons respectively. The changes were biallelic, with one exception. Incidence of IIH in Polish population estimated on the basis of allele frequency of recurrent p.R396W CYP24A1 variant, is 1:32,465 births. It indicates that at least a thousand homozygotes and compound heterozygotes with risk of IIH live in the country. Differences in mechanism of developing hypercalcemia indicate that its prevention may vary in both IIH defects. Theoretically, vit. D restriction is a first indication for CYP24A1 defect (which disturbs 1,25(OH) 2 D degradation) and phosphate supplementation for SLC34A1 defect (which impairs renal phosphate transport). In conclusion, we suggest that molecular testing for CYP24A1 and SLC34A1 mutations should be performed in each case of idiopathic hypercalcemia/hypercalciuria, both in children and adults, to determine the proper way for acute treatment and complications prevention.

Aquaporin-2: new mutations responsible for autosomal-recessive nephrogenic diabetes insipidus—update and epidemiology

PubMed Central

El Tarazi, Abdulah; Matar, Jessica; Lussier, Yoann; Arthus, Marie-Françoise; Lonergan, Michèle; Bockenhauer, Detlef; Bissonnette, Pierre

2012-01-01

It is clinically useful to distinguish between two types of hereditary nephrogenic diabetes insipidus (NDI): a ‘pure’ type characterized by loss of water only and a complex type characterized by loss of water and ions. Patients with congenital NDI bearing mutations in the vasopressin 2 receptor gene, AVPR2, or in the aquaporin-2 gene, AQP2, have a pure NDI phenotype with loss of water but normal conservation of sodium, potassium, chloride and calcium. Patients with hereditary hypokalemic salt-losing tubulopathies have a complex phenotype with loss of water and ions. They have polyhydramnios, hypercalciuria and hypo- or isosthenuria and were found to bear KCNJ1 (ROMK) and SLC12A1 (NKCC2) mutations. Patients with polyhydramnios, profound polyuria, hyponatremia, hypochloremia, metabolic alkalosis and sensorineural deafness were found to bear BSND mutations. These clinical phenotypes demonstrate the critical importance of the proteins ROMK, NKCC2 and Barttin to transfer NaCl in the medullary interstitium and thereby to generate, together with urea, a hypertonic milieu. This editorial describes two new developments: (i) the genomic information provided by the sequencing of the AQP2 gene is key to the routine care of these patients, and, as in other genetic diseases, reduces health costs and provides psychological benefits to patients and families and (ii) the expression of AQP2 mutants in Xenopus oocytes and in polarized renal tubular cells recapitulates the clinical phenotypes and reveals a continuum from severe loss of function with urinary osmolalities <150 mOsm/kg H2O to milder defects with urine osmolalities >200 mOsm/kg H2O. PMID:26069764

Bone Resorption and Environmental Exposure to Cadmium in Women: A Population Study

PubMed Central

Schutte, Rudolph; Nawrot, Tim S.; Richart, Tom; Thijs, Lutgarde; Vanderschueren, Dirk; Kuznetsova, Tatiana; Van Hecke, Etienne; Roels, Harry A.; Staessen, Jan A.

2008-01-01

Background Environmental exposure to cadmium decreases bone density indirectly through hypercalciuria resulting from renal tubular dysfunction. Objective We sought evidence for a direct osteotoxic effect of cadmium in women. Methods We randomly recruited 294 women (mean age, 49.2 years) from a Flemish population with environmental cadmium exposure. We measured 24-hr urinary cadmium and blood cadmium as indexes of lifetime and recent exposure, respectively. We assessed the multivariate-adjusted association of exposure with specific markers of bone resorption, urinary hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP), as well as with calcium excretion, various calciotropic hormones, and forearm bone density. Results In all women, the effect sizes associated with a doubling of lifetime exposure were 8.4% (p = 0.009) for HP, 6.9% (p = 0.10) for LP, 0.77 mmol/day (p = 0.003) for urinary calcium, –0.009 g/cm2 (p = 0.055) for proximal forearm bone density, and –16.8% (p = 0.065) for serum parathyroid hormone. In 144 postmenopausal women, the corresponding effect sizes were –0.01223 g/cm2 (p = 0.008) for distal forearm bone density, 4.7% (p = 0.064) for serum calcitonin, and 10.2% for bone-specific alkaline phosphatase. In all women, the effect sizes associated with a doubling of recent exposure were 7.2% (p = 0.001) for urinary HP, 7.2% (p = 0.021) for urinary LP, –9.0% (p = 0.097) for serum parathyroid hormone, and 5.5% (p = 0.008) for serum calcitonin. Only one woman had renal tubular dysfunction (urinary retinol-binding protein > 338 μg/day). Conclusions In the absence of renal tubular dysfunction, environmental exposure to cadmium increases bone resorption in women, suggesting a direct osteotoxic effect with increased calciuria and reactive changes in calciotropic hormones. PMID:18560534

Dietary cadmium exposure and kidney stone incidence: a population-based prospective cohort study of men & women.

PubMed

Thomas, Laura D K; Elinder, Carl-Gustaf; Tiselius, Hans-Göran; Wolk, Alicja; Akesson, Agneta

2013-09-01

Cadmium exposure is associated with increased urinary calcium excretion. Hypercalciuria is recognised as a major risk factor for kidney stone formation. Increased prevalence of kidney stones among those occupationally exposed to cadmium has previously been suggested. Food is the main source of cadmium exposure in the general population with tobacco representing an important additional source among smokers. We aimed to assess the association between dietary cadmium exposure and kidney stone incidence in two large population-based, prospective cohorts of men (Cohort of Swedish Men; COSM) and women (The Swedish Mammography Cohort; SMC). Those with a history of kidney stones were excluded. At baseline 1997, men (45-79yrs) and women (48 to 83yrs), completed a self-administered questionnaire on diet and lifestyle. During 12years of follow-up, we ascertained 707 cases of kidney stones in men and 290 in women through linkage of the cohorts to the national inpatient and outpatient registers. Individual dietary cadmium exposure was estimated using dietary data and concentrations of cadmium in food. Hazard ratios (HR) were calculated using the Cox proportional hazards regression models with adjustment for other risk factors. Estimated dietary cadmium exposure was not associated with increased kidney stone incidence among men HR 0.97 (95% confidence interval (CI): 0.77-1.23) or women HR 0.99 (95% CI: 0.89-1.43), comparing the highest tertile with the lowest. In conclusion, our results do not support a strong association between dietary cadmium and kidney stone risk at the exposure levels seen in the general population. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evidence Report: Risk of Renal Stone Formation

NASA Technical Reports Server (NTRS)

Sibonga, Jean D.; Pietrzyk, Robert

2017-01-01

The formation of renal stones poses an in-flight health risk of high severity, not only because of the impact of renal colic on human performance but also because of complications that could potentially lead to crew evacuation, such as hematuria, infection, hydronephrosis, and sepsis. Evidence for risk factors comes from urine analyses of crewmembers, documenting changes to the urinary environment that are conducive to increased saturation of stone-forming salts, which are the driving force for nucleation and growth of a stone nidus. Further, renal stones have been documented in astronauts after return to Earth and in one cosmonaut during flight. Biochemical analysis of urine specimens has provided indication of hypercalciuria and hyperuricemia, reduced urine volumes, and increased urine saturation of calcium oxalate and calcium phosphate. A major contributor to the risk for renal stone formation is bone atrophy with increased turnover of the bone minerals. Dietary and fluid intakes also play major roles in the risk because of the influence on urine pH (more acidic) and on volume (decreased). Historically, specific assessments on urine samples from some Skylab crewmembers indicated that calcium excretion increased early in flight, notable by day 10 of flight, and almost exceeded the upper threshold for normal excretion (300mg/day in males). Other crewmember data documented reduced intake of fluid and reduced intake of potassium, phosphorus, magnesium, and citrate (an inhibitor of calcium stone formation) in the diet. Hence, data from both short-duration and long-duration missions indicate that space travel induces risk factors for renal stone formation that continue to persist after flight; this risk has been documented by reported kidney stones in crewmembers.

Vitamin D supplementation guidelines.

PubMed

Pludowski, Pawel; Holick, Michael F; Grant, William B; Konstantynowicz, Jerzy; Mascarenhas, Mario R; Haq, Afrozul; Povoroznyuk, Vladyslav; Balatska, Nataliya; Barbosa, Ana Paula; Karonova, Tatiana; Rudenka, Ema; Misiorowski, Waldemar; Zakharova, Irina; Rudenka, Alena; Łukaszkiewicz, Jacek; Marcinowska-Suchowierska, Ewa; Łaszcz, Natalia; Abramowicz, Pawel; Bhattoa, Harjit P; Wimalawansa, Sunil J

2018-01-01

Research carried out during the past two-decades extended the understanding of actions of vitamin D, from regulating calcium and phosphate absorption and bone metabolism to many pleiotropic actions in organs and tissues in the body. Most observational and ecological studies report association of higher serum 25-hydroxyvitamin D [25(OH)D] concentrations with improved outcomes for several chronic, communicable and non-communicable diseases. Consequently, numerous agencies and scientific organizations have developed recommendations for vitamin D supplementation and guidance on optimal serum 25(OH)D concentrations. The bone-centric guidelines recommend a target 25(OH)D concentration of 20ng/mL (50nmol/L), and age-dependent daily vitamin D doses of 400-800IU. The guidelines focused on pleiotropic effects of vitamin D recommend a target 25(OH)D concentration of 30ng/mL (75nmol/L), and age-, body weight-, disease-status, and ethnicity dependent vitamin D doses ranging between 400 and 2000IU/day. The wise and balanced choice of the recommendations to follow depends on one's individual health outcome concerns, age, body weight, latitude of residence, dietary and cultural habits, making the regional or nationwide guidelines more applicable in clinical practice. While natural sources of vitamin D can raise 25(OH)D concentrations, relative to dietary preferences and latitude of residence, in the context of general population, these sources are regarded ineffective to maintain the year-round 25(OH)D concentrations in the range of 30-50ng/mL (75-125nmol/L). Vitamin D self-administration related adverse effects, such as hypercalcemia and hypercalciuria are rare, and usually result from taking extremely high doses of vitamin D for a prolonged time. Copyright © 2017 Elsevier Ltd. All rights reserved.

Safety and T Cell Modulating Effects of High Dose Vitamin D3 Supplementation in Multiple Sclerosis

PubMed Central

Smolders, Joost; Peelen, Evelyn; Thewissen, Mariëlle; Cohen Tervaert, Jan Willem; Menheere, Paul; Hupperts, Raymond; Damoiseaux, Jan

2010-01-01

Background A poor vitamin D status has been associated with a high disease activity of multiple sclerosis (MS). Recently, we described associations between vitamin D status and peripheral T cell characteristics in relapsing remitting MS (RRMS) patients. In the present study, we studied the effects of high dose vitamin D3 supplementation on safety and T cell related outcome measures. Methodology/Principal Findings Fifteen RRMS patients were supplemented with 20 000 IU/d vitamin D3 for 12 weeks. Vitamin D and calcium metabolism were carefully monitored, and T cell characteristics were studied by flowcytometry. All patients finished the protocol without side-effects, hypercalcaemia, or hypercalciuria. The median vitamin D status increased from 50 nmol/L (31–175) at week 0 to 380 nmol/L (151–535) at week 12 (P<0.001). During the study, 1 patient experienced an exacerbation of MS and was censored from the T cell analysis. The proportions of (naïve and memory) CD4+ Tregs remained unaffected. Although Treg suppressive function improved in several subjects, this effect was not significant in the total cohort (P = 0.143). An increased proportion of IL-10+ CD4+ T cells was found after supplementation (P = 0.021). Additionally, a decrease of the ratio between IFN-γ+ and IL-4+ CD4+ T cells was observed (P = 0.035). Conclusion/Significance Twelve week supplementation of high dose vitamin D3 in RRMS patients was well tolerated and did not induce decompensation of calcium metabolism. The skewing towards an anti-inflammatory cytokine profile supports the evidence on vitamin D as an immune-modulator, and may be used as outcome measure for upcoming randomized placebo-controlled trials. Trial Registration Clinicaltrials.gov NCT00940719 PMID:21179201

Clinical and molecular aspects of distal renal tubular acidosis in children.

PubMed

Besouw, Martine T P; Bienias, Marc; Walsh, Patrick; Kleta, Robert; Van't Hoff, William G; Ashton, Emma; Jenkins, Lucy; Bockenhauer, Detlef

2017-06-01

Distal renal tubular acidosis (dRTA) is characterized by hyperchloraemic metabolic acidosis, hypokalaemia, hypercalciuria and nephrocalcinosis. It is due to reduced urinary acidification by the α-intercalated cells in the collecting duct and can be caused by mutations in genes that encode subunits of the vacuolar H + -ATPase (ATP6V1B1, ATP6V0A4) or the anion exchanger 1 (SLC4A1). Treatment with alkali is the mainstay of therapy. This study is an analysis of clinical data from a long-term follow-up of 24 children with dRTA in a single centre, including a genetic analysis. Of the 24 children included in the study, genetic diagnosis was confirmed in 19 patients, with six children having mutations in ATP6V1B1, ten in ATP6V0A4 and three in SLC4A1; molecular diagnosis was not available for five children. Five novel mutations were detected (2 in ATP6V1B1 and 3 in ATP6V0A4). Two-thirds of patients presented with features of proximal tubular dysfunction leading to an erroneous diagnosis of renal Fanconi syndrome. The proximal tubulopathy disappeared after resolution of acidosis, indicating the importance of following proximal tubular function to establish the correct diagnosis. Growth retardation with a height below -2 standard deviation score was found in ten patients at presentation, but persisted in only three of these children once established on alkali treatment. Sensorineural hearing loss was found in five of the six patients with an ATP6V1B1 mutation. Only one patient with an ATP6V0A4 mutation had sensorineural hearing loss during childhood. Nine children developed medullary cysts, but without apparent clinical consequences. Cyst development in this cohort was not correlated with age at therapy onset, molecular diagnosis, growth parameters or renal function. In general, the prognosis of dRTA is good in children treated with alkali.

Flexible ureteroscopic laser lithotripsy for upper urinary tract stone disease in patients with spinal cord injury.

PubMed

Tepeler, Abdulkadir; Sninsky, Brian C; Nakada, Stephen Y

2015-11-01

The objective of this study is to present the outcomes of flexible ureteroscopic laser lithotripsy (URS) for upper urinary tract stone disease in spinal cord injury (SCI) patients performed by a single surgeon. A retrospective analysis was performed for SCI patients treated with flexible URS for proximal ureter and kidney stone disease by a single surgeon between 2003 and 2013. Patient characteristics, operative outcomes, metabolic evaluation, and stone analyses were assessed in detail. A total of 27 URS procedures were performed for urolithiasis in 21 renal units of 19 patients. The mean age was 52.1 ± 15.6 years (16-72) and mean BMI was 29.2 ± 7.3 kg/m(2) (20-45.7). Etiology of SCI was trauma (n: 10), multiple sclerosis (n: 6), cerebrovascular accident (n: 1), or undetermined (n: 2). The mean stone size was 15.9 ± 8.6 (6-40) mm. In the 27 URS procedures, stones were located in the ureter (n: 5), the kidney (n: 14), and both areas (n: 8). Mean hospitalization time was 2.0 ± 2.4 (0-10) days. Postoperative complications were observed in 6 cases (22.2%). Three major complications included urosepsis (n: 1) and respiratory failure (n: 2), that were observed postoperatively and required admission to the intensive care unit. The 2 minor complications were hypotension, fever and UTI, and required medical treatment. Fourteen (66.6%) of the 21 renal units were stone free. Calcium phosphate carbonate (n: 9) and struvite (n: 5) were the primary stone compositions detected. Hypocitraturia (n: 6), hypercalciuria (n: 5), hypernaturia (n: 5), hyperoxaluria (n: 4), and hyperuricosuria (n: 1) were common abnormalities in 24-h urine analysis. Ureteroscopic laser lithotripsy can be an effective treatment modality for SCI patients with upper urinary tract calculi.

The role of calbindin-D28k on renal calcium and magnesium handling during treatment with loop and thiazide diuretics

PubMed Central

Lee, Chien-Te; Ng, Hwee-Yeong; Lee, Yueh-Ting; Lai, Li-Wen

2015-01-01

Calbindin-D28k (CBD-28k) is a calcium binding protein located in the distal convoluted tubule (DCT) and plays an important role in active calcium transport in the kidney. Loop and thiazide diuretics affect renal Ca and Mg handling: both cause Mg wasting, but have opposite effects on Ca excretion as loop diuretics increase, but thiazides decrease, Ca excretion. To understand the role of CBD-28k in renal Ca and Mg handling in response to diuretics treatment, we investigated renal Ca and Mg excretion and gene expression of DCT Ca and Mg transport molecules in wild-type (WT) and CBD-28k knockout (KO) mice. Mice were treated with chlorothiazide (CTZ; 50 mg·kg−1·day−1) or furosemide (FSM; 30 mg·kg−1·day−1) for 3 days. To avoid volume depletion, salt was supplemented in the drinking water. Urine Ca excretion was reduced in WT, but not in KO mice, by CTZ. FSM induced similar hypercalciuria in both groups. DCT Ca transport molecules, including transient receptor potential vanilloid 5 (TRPV5), TRPV6, and CBD-9k, were upregulated by CTZ and FSM in WT, but not in KO mice. Urine Mg excretion was increased and transient receptor potential subfamily M, member 6 (TRPM6) was upregulated by both CTZ and FSM in WT and KO mice. In conclusion, CBD-28k plays an important role in gene expression of DCT Ca, but not Mg, transport molecules, which may be related to its being a Ca, but not a Mg, intracellular sensor. The lack of upregulation of DCT Ca transport molecules by thiazides in the KO mice indicates that the DCT Ca transport system is critical for Ca conservation by thiazides. PMID:26582761

[Comparative efficacy of nitrofurans in children and adolescents with pyelonephritis in presence of crystalluria].

PubMed

Aver'anova, N I; Balueva, L G; Ivanova, N V

2013-01-01

To evaluate the efficacy of nitrofurans in children and adolescents with pyelonephritis in the presence of crystalluria. The study included 50 patients aged 4-14 years with chronic pyelonephritis in the presence of dysmetabolism. The patients underwent general blood test, general urinalysis with an urocytogram, bacteriological examination of urine, biochemical test of serum (uric acid, calcium, phosphorus, magnesium, urea, and creatinine) and 24-hour urinary excretion (uric acid, oxalates, calcium, phosphorus, and magnesium) at hospital admission and over time. The treatment regimen for Group 1 patients after antibiotic therapy involved furamag, Group 2 received furagin. The drugs were used in a dosage of 2 mg/kg/day in 2 divided doses for 14 days. Complaints, major clinical manifestations, crystalluria patterns, and a number of laboratory findings were analyzed over time. The urinary sediment showed leukocyturia and bacteriuria in all the patients, oxaluria in 70% of the patients, uraturia in 10%, and mixed crystalluria in 20%. The main etiological agent of pyelonephritis was Escherichia coli (48.4%). Increased serum uric acid concentrations were revealed in 14% of the patients. Daily urine tests revealed hyperoxaluria, hyperuricosuria, and hypercalciuria in 86, 18, and 8% of the patients, respectively; urinary magnesium excretion was reduced in 86%. After treatment, Group 1 patients showed a more marked therapeutic effect in terms of a number of indicators (leukocyturia, crystalluria, uricosuria, magnesuria). The results of the study showed that the antibacterial therapy involving antibiotics and nitrofurans for an exacerbation of chronic pyelonephritis in the presence of crystalluria not only provides an anti-inflammatory effect, but also leads to reductions in the level of crystalluria and the urinary content of uric acid and calcium. There was a significantly marked reduction in crystalluria, serum uric acid, and urinary oxalates and calcium in the children taking furamag. Out of nitrofurans, furamag may be recommended as the drug of choice to treat urinary tract infections in the presence of crystalluria.

Hypervitaminosis D mediates compensatory Ca2+ hyperabsorption in TRPV5 knockout mice.

PubMed

Renkema, Kirsten Y; Nijenhuis, Tom; van der Eerden, Bram C J; van der Kemp, Annemiete W C M; Weinans, Harrie; van Leeuwen, Johannes P T M; Bindels, René J M; Hoenderop, Joost G J

2005-11-01

Vitamin D plays an important role in Ca(2+) homeostasis by controlling Ca(2+) (re)absorption in intestine, kidney, and bone. The epithelial Ca(2+) channel TRPV5 mediates the Ca(2+) entry step in active Ca(2+) reabsorption. TRPV5 knockout (TRPV5(-/-)) mice show impaired Ca(2+) reabsorption, hypercalciuria, hypervitaminosis D, and intestinal hyperabsorption of Ca(2+). Moreover, these mice demonstrate upregulation of intestinal TRPV6 and calbindin-D(9K) expression compared with wild-type mice. For addressing the role of the observed hypervitaminosis D in the maintenance of Ca(2+) homeostasis and the regulation of expression levels of the Ca(2+) transport proteins in kidney and intestine, TRPV5/25-hydroxyvitamin-D(3)-1alpha-hydroxylase double knockout (TRPV5(-/-)/1alpha-OHase(-/-)) mice, which show undetectable serum 1,25(OH)(2)D(3) levels, were generated. TRPV5(-/-)/1alpha-OHase(-/-) mice displayed a significant hypocalcemia compared with wild-type mice (1.10 +/- 0.02 and 2.54 +/- 0.01 mM, respectively; P < 0.05). mRNA levels of renal calbindin-D(28K) (7 +/- 2%), calbindin-D(9K) (32 +/- 4%), Na(+)/Ca(2+) exchanger (12 +/- 2%), and intestinal TRPV6 (40 +/- 8%) and calbindin-D(9K) (26 +/- 4%) expression levels were decreased compared with wild-type mice. Hyperparathyroidism and rickets were present in TRPV5(-/-)/1alpha-OHase(-/-) mice, more pronounced than observed in single TRPV5 or 1alpha-OHase knockout mice. It is interesting that a renal Ca(2+) leak, as demonstrated in TRPV5(-/-) mice, persisted in TRPV5(-/-)/1alpha-OHase(-/-) mice, but a compensatory upregulation of intestinal Ca(2+) transporters was abolished. In conclusion, the elevation of serum 1,25(OH)(2)D(3) levels in TRPV5(-/-) mice is responsible for the upregulation of intestinal Ca(2+) transporters and Ca(2+) hyperabsorption. Hypervitaminosis D, therefore, is of crucial importance to maintain normocalcemia in impaired Ca(2+) reabsorption in TRPV5(-/-) mice.

Clinical and biochemical findings in Mexican patients with distal renal tubular acidosis.

PubMed

Guerra-Hernández, Norma; Matos-Martínez, Mario; Ordaz-López, Karen Verónica; Camargo-Muñiz, María Dolores; Medeiros, Mara; Escobar-Pérez, Laura

2014-01-01

Renal tubular acidosis (RTA) is a rare disease characterized by a normal serum anion gap, sustained metabolic acidosis, low concentration of plasma bicarbonate, variable hyperchloremia and hypokalemia and conserved glomerular filtration rate. RTA is developed during the first year of life and produces failure to thrive and anorexia. Primary distal RTA (type 1) is a renal syndrome with a reduced ability to excrete the acid load through the collecting ducts and impairment to concentrate the urine causing polyuria and dehydration. Evaluate the current health status and describe the clinical findings and progress of Mexican patients with distal RTA. Demonstrate the distal urinary acidification defect by measuring the urinary pCO2 tension in alkaline urines. We looked for infants in tertiary care hospitals with a clinical history of normal serum anion gap, metabolic acidosis, hypokalemia, hyperchloremia, nephrocalcinosis, sensorineural hearing loss and inability for urine acidification under systemic metabolic acidosis. Biochemical analysis were performed periodically. Alkali medication was not suspended in one patient to assess urinary acidification with oral administration of sodium bicarbonate (2 mEq/Kg) and acetazolamide (500 mg/1.73 m2 body surface). Urinary pCO2 levels were determined at 60 and 90 min. Three children, one adolescent and one adult with distal RTA were found. They had an infant history of dehydration, failure to thrive, anorexia, vomiting, muscle paralysis, hypercalciuria, urinary infections, polyuria, polydipsia and polyhidramnios during pregnancy. Severe nephrocalcinosis was detected in all patients whereas sensorineural hearing loss was developed in four cases. Under the alkali medication all cases but one were normocalciuric. A patient developed kidney failure. The urinary acidification test confirmed the innability to eliminate the acid load. Early diagnosis in infancy and continuos alkali medication were of great benefit for most of the patients. Urinary pCO2 levels in alkaline urine provided an index for collecting duct hydrogen-ion secretion. To our knowledge this is the first report of mexican patients with distal RTA.

Clinical utility of routine laboratory testing to identify possible secondary causes in older men with osteoporosis: the Osteoporotic Fractures in Men (MrOS) Study

PubMed Central

Fink, Howard A.; Litwack-Harrison, Stephanie; Taylor, Brent C.; Bauer, Douglas C.; Orwoll, Eric S.; Lee, Christine G.; Barrett-Connor, Elizabeth; Schousboe, John T.; Kado, Deborah M.; Garimella, Pranav S.; Ensrud, Kristine E.

2016-01-01

Purpose To evaluate the utility of recommended laboratory testing to identify secondary causes in older men with osteoporosis, we examined prevalence of laboratory abnormalities in older men with and without osteoporosis. Methods 1572 men aged ≥65 years in the Osteoporotic Fractures in Men study completed bone mineral density (BMD) testing and a battery of laboratory measures, including serum calcium, phosphorus, alkaline phosphatase, parathyroid hormone (PTH), thyroid-stimulating hormone (TSH), 25-OH vitamin D, total testosterone, spot urine calcium/creatinine ratio, spot urine albumin-creatinine ratio, creatinine-derived estimate glomerular filtration rate, 24-hour urine calcium, and 24-hour urine free cortisol. Using cross-sectional analyses, we calculated prevalence ratios (PR) and 95% confidence intervals (CI) for the association of any and specific laboratory abnormalities with osteoporosis, and the number of men with osteoporosis needed to test to identify one additional laboratory abnormality compared to testing men without osteoporosis. Results Approximately 60% of men had ≥1 laboratory abnormality in both men with and without osteoporosis. Among individual tests, only vitamin D insufficiency (PR, 1.13; 95% CI, 1.05–1.22) and high alkaline phosphatase (PR, 3.05; 95% CI, 1.52–6.11) were more likely in men with osteoporosis. Hypercortisolism and hyperthyroidism were uncommon and not significantly more frequent in men with osteoporosis. No osteoporotic men had hypercalciuria. Conclusions Though most of these older men had ≥1 laboratory abnormality, few routinely recommended individual tests were more common in men with osteoporosis than in those without osteoporosis. Possibly excepting vitamin D and alkaline phosphatase, benefit of routine laboratory testing to identify possible secondary causes in older osteoporotic men appears low. Results may not be generalizable to younger men or to older men in whom history and exam findings raise clinical suspicion for a secondary cause of osteoporosis. PMID:26458388

Gonadotrophin abnormalities in an infant with Lowe syndrome.

PubMed

Warner, Bronwen E; Inward, Carol D; Burren, Christine P

2017-01-01

This case, presenting with bilateral impalpable testes, illustrates the relevance of a broad differential disorders of sex development case management. It provides new insights on hypothalamic-pituitary-gonadal (HPG) axis and testicular function abnormalities in the multisystem disorder of Lowe syndrome. Lowe syndrome, also known as oculocerebrorenal syndrome, is a rare disorder characterised by eye abnormalities, central nervous system involvement and proximal renal tubular acidosis. There are a handful of reports of pubertal delay, infertility and cryptorchidism in Lowe syndrome. Biochemistry aged 72 h: testosterone 6.4 nmol/L, LH <0.5 IU/L and FSH <0.5 IU/L. Gonadotropin-releasing hormone stimulation test identified significantly raised baseline LH = 45.4 IU/L (contrasts with earlier undetectable LH), with a 20% increase on stimulation, while baseline FSH = 4.3 IU/L with no increase on stimulation. Day 14 HCG stimulation test produced an acceptable 50% increase in testosterone. The constellation of further abnormalities suggested Lowe syndrome: hypotonia, bilateral cataracts (surgical extraction and intraocular lens implantation) and renal tubular acidosis (microscopic haematuria, hypercalciuria, proteinuria, generalised aminoaciduria, hypophosphataemia and metabolic acidosis). DNA sequencing identified de novo hemizygous frameshift mutation OCRL c.2409_2410delCT in exon 22. Interpretation of initial and repeat GnRH and HCG testing indicates the likelihood of testicular failure. Partial testicular descent occurred but left orchidopexy was required. Improving long-term gonadal function in Lowe syndrome assumes increased importance for current cohorts as advances in renal replacement therapy have greatly improved life expectancy. Noting HPG axis abnormalities in Lowe syndrome in infancy can identify cases requiring increased surveillance of pubertal progress for earlier detection and management. Clinical endocrine problems in Lowe syndrome has been reported, but has focused on abnormalities in adolescence and young adulthood: pubertal delay and infertility.We present an infant with isolated LH elevation at baseline and on GnRH stimulation testing who also had bilateral impalpable testes.Early testing of the HPG axis in patients with Lowe syndrome may help predict gonadal abnormalities from a younger age, which will enhance the overall case management into adolescence.

Randomized trial of the anti-FGF23 antibody KRN23 in X-linked hypophosphatemia

PubMed Central

Carpenter, Thomas O.; Imel, Erik A.; Ruppe, Mary D.; Weber, Thomas J.; Klausner, Mark A.; Wooddell, Margaret M.; Kawakami, Tetsuyoshi; Ito, Takahiro; Zhang, Xiaoping; Humphrey, Jeffrey; Insogna, Karl L.; Peacock, Munro

2014-01-01

Background. X-linked hypophosphatemia (XLH) is the most common heritable form of rickets and osteomalacia. XLH-associated mutations in phosphate-regulating endopeptidase (PHEX) result in elevated serum FGF23, decreased renal phosphate reabsorption, and low serum concentrations of phosphate (inorganic phosphorus, Pi) and 1,25-dihydroxyvitamin D [1,25(OH)2D]. KRN23 is a human anti-FGF23 antibody developed as a potential treatment for XLH. Here, we have assessed the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of KRN23 following a single i.v. or s.c. dose of KRN23 in adults with XLH. Methods. Thirty-eight XLH patients were randomized to receive a single dose of KRN23 (0.003–0.3 mg/kg i.v. or 0.1–1 mg/kg s.c.) or placebo. PK, PD, immunogenicity, safety, and tolerability were assessed for up to 50 days. Results. KRN23 significantly increased the maximum renal tubular threshold for phosphate reabsorption (TmP/GFR), serum Pi, and 1,25(OH)2D compared with that of placebo (P < 0.01). The maximum serum Pi concentration occurred later following s.c. dosing (8–15 days) compared with that seen with i.v. dosing (0.5–4 days). The effect duration was dose related and persisted longer in patients who received s.c. administration. Changes from baseline in TmP/GFR, serum Pi, and serum 1,25(OH)2D correlated with serum KRN23 concentrations. The mean t1/2 of KRN23 was 8–12 days after i.v. administration and 13–19 days after s.c. administration. Patients did not exhibit increased nephrocalcinosis or develop hypercalciuria, hypercalcemia, anti-KRN23 antibodies, or elevated serum parathyroid hormone (PTH) or creatinine. Conclusion. KRN23 increased TmP/GFR, serum Pi, and serum 1,25(OH)2D. The positive effect of KR23 on serum Pi and its favorable safety profile suggest utility for KRN23 in XLH patients. Trial registration. Clinicaltrials.gov NCT00830674. Funding. Kyowa Hakko Kirin Pharma, Inc. PMID:24569459

A 7-day continuous infusion of PTH or PTHrP suppresses bone formation and uncouples bone turnover.

PubMed

Horwitz, Mara J; Tedesco, Mary Beth; Sereika, Susan M; Prebehala, Linda; Gundberg, Caren M; Hollis, Bruce W; Bisello, Alessandro; Garcia-Ocaña, Adolfo; Carneiro, Raquel M; Stewart, Andrew F

2011-09-01

Human in vivo models of primary hyperparathyroidism (HPT), humoral hypercalcemia of malignancy (HHM), or lactational bone mobilization for more than 48 hours have not been described previously. We therefore developed 7-day continuous-infusion models using human parathyroid hormone(1-34) [hPTH(1-34)] and human parathyroid hormone-related protein(1-36) [hPTHrP(1-36)] in healthy human adult volunteers. Study subjects developed sustained mild increases in serum calcium (10.0 mg/dL), with marked suppression of endogenous PTH(1-84). The maximal tolerated infused doses over a 7-day period (2 and 4 pmol/kg/h for PTH and PTHrP, respectively) were far lower than in prior, briefer human studies (8 to 28 pmol/kg/h). In contrast to prior reports using higher PTH and PTHrP doses, both 1,25-dihydroxyvitamin D(3) [1,25(OH)(2) D(3) ] and tubular maximum for phosphorus (TmP/GFR) remained unaltered with these low doses despite achievement of hypercalcemia and hypercalciuria. As expected, bone resorption increased rapidly and reversed promptly with cessation of the infusion. However, in contrast to events in primary HPT, bone formation was suppressed by 30% to 40% for the 7 days of the infusions. With cessation of PTH and PTHrP infusion, bone-formation markers abruptly rebounded upward, confirming that bone formation is suppressed by continuous PTH or PTHrP infusion. These studies demonstrate that continuous exposure of the human skeleton to PTH or PTHrP in vivo recruits and activates the bone-resorption program but causes sustained arrest in the osteoblast maturation program. These events would most closely mimic and model events in HHM. Although not a perfect model for lactation, the increase in resorption and the rebound increase in formation with cessation of the infusions are reminiscent of the maternal skeletal calcium mobilization and reversal that occur following lactation. The findings also highlight similarities and differences between the model and HPT. Copyright © 2011 American Society for Bone and Mineral Research.

Vitamin D, calcium, and cardiovascular mortality: a perspective from a plenary lecture given at the annual meeting of the American Association of Clinical Endocrinologists.

PubMed

Miller, Paul D

2011-01-01

To examine data showing associations between serum 25-hydroxyvitamin D levels and calcium intake and cardiovascular mortality. The articles reviewed include those published from 1992-2011 derived from search engines (PubMed, Scopus, Medscape) using the following search terms: vitamin D, calcium, cardiovascular events, cardiovascular mortality, all-cause mortality, vascular calcification, chronic kidney disease, renal stones, and hypercalciuria. Because these articles were not weighted (graded) on the level of evidence, this review reflects my own perspective on the data and how they should be applied to clinical management. For skeletal health, vitamin D and calcium are both needed to ensure proper skeletal growth (modeling) and repair (remodeling). Nutritional deficiencies of either vitamin D or calcium may lead to a spectrum of metabolic bone disorders. Excessive consumption of either nutrient has been linked to a variety of medical disorders, such as hypercalcemia or renal stones. There have also been associations between vitamin D or calcium intake and cardiovascular disease. However, neither of these associations have established evidence nor known causality for increasing cardiovascular risk or all-cause mortality in patients with creatinine clearances greater than 60 mL/min. In patients with more severe chronic kidney disease, stronger data link excess calcium (or phosphorus) intake and increase in vascular calcification, but not mortality. The safe upper limit for vitamin D intake is at least 4000 IU daily and probably 10 000 IU daily; for calcium, the safe upper limit is between 2000 and 3000 mg daily. While no solid scientific evidence validates that serum vitamin D levels between 15 and 70 ng/mL are associated with increased cardiovascular disease risk, stronger but inconsistent evidence shows an association between calcium supplementation greater than 500 mg daily and an increase in cardiovascular disease risk. Most professional societies suggest that replacement levels of these nutrients be personalized with the goal of reaching a 25-hydroxyvitamin D concentration between 30 and 50 ng/mL and a calcium intake of 1200 mg daily.

Mutations in ATP6V1B1 and ATP6V0A4 genes cause recessive distal renal tubular acidosis in Mexican families.

PubMed

Escobar, Laura I; Simian, Christopher; Treard, Cyrielle; Hayek, Donia; Salvador, Carolina; Guerra, Norma; Matos, Mario; Medeiros, Mara; Enciso, Sandra; Camargo, María Dolores; Vargas-Poussou, Rosa

2016-05-01

Autosomal recessive distal renal tubular acidosis (dRTA) is a rare disease characterized by a hyperchloremic metabolic acidosis with normal anion gap, hypokalemia, hypercalciuria, hypocitraturia, nephrocalcinosis, and conserved glomerular filtration rate. In some cases, neurosensorial deafness is associated. dRTA is developed during the first months of life and the main manifestations are failure to thrive, vomiting, dehydration, and anorexia. Nine unrelated families were studied: seven children, a teenager, and an adult with dRTA. Hearing was preserved in four children. Coding regions of the genes responsible for recessive dRTA were analysed by Sanger sequencing. Molecular defects were found in the genes ATP6V1B1 and ATP6V0A4. We identified three homozygous variants in ATP6V1B: a frameshift mutation (p.Ile386Hisfs*56), a nucleotide substitution in exon 10 (p.Pro346Arg), and a new splicing mutation in intron 5. Three patients were homozygous for one novel (p.Arg743Trp) and one known (p.Asp411Tyr) missense mutations in the ATP6V0A4 gene. Three patients were compound heterozygous: one proband displayed two novel mutations, the frameshift mutation p.Val52Metfs*25, and a large deletion of exons 18-21; two probands showed the missense mutation p.Asp411Tyr and as a second mutation, p.Arg194Ter and c.1691+2dup, respectively. ATP6V0A4 and ATP6V1B1 genes were involved in recessive dRTA of Mexican families. All ATP6V1B1 mutations detected were homozygous and all patients developed sensorineural hearing loss (SNHL) early in infancy. ATP6V0A4 mutations were found in one infant and three children without SNHL, and in one teenager and one adult with SNHL confirming the phenotypic variability in this trait. The mutation p.Asp411Tyr detected in four Mexican families was due to a founder effect. Screening of these mutations could provide a rapid and valuable tool for diagnosis of dRTA in this population.

Update of Bisphosphonate Flight Experiment

NASA Technical Reports Server (NTRS)

LeBlanc, A.; Matsumoto, T.; Jones, J.; Shapiro, J.; Lang, T.; Shackelford, L.; Smith, S. M.; Evans, H.; Spector, E.; Snyder, R. P.;

Can Stoss Therapy Be Used in Children with Vitamin D Deficiency or Insufficiency without Rickets?

PubMed

Koçyiğit, Cemil; Çatlı, Gönül; İnce, Gülberat; Özkan, Elif Büşra; Dündar, Bumin Nuri

2017-06-01

Stoss vitamin D treatment has been recommended for its non-skeletal benefits in adults, but there is a lack of data on the optimal dose of vitamin D stoss therapy in children with vitamin D deficiency/insufficiency without rickets. This study aimed to compare efficiency/side effects of two different stoss therapy regimens (10 000 IU/kg and 300 000 IU vitamin D3) administered in children with vitamin D deficiency/insufficiency without rickets. Sixty-four children who had vitamin D deficiency/insufficiency were studied. A serum 25-hydroxyvitamin-D (25-OH-D) level of 15-20 ng/mL was considered as vitamin D insufficient and <15 ng/mL was considered as vitamin D deficient. The patients were divided into two groups according to the stoss therapy doses they received. Serum calcium, phosphate, alkaline phosphatase, 25-OH-D, parathyroid hormone levels, and spot urine calcium/creatinine ratios before/after treatment were recorded. Wrist radiography and renal ultrasonography were performed. The mean age of the subjects was 10.6±4.4 years. Thirty-two children were treated with a single vitamin D3 dose of 10 000 IU/kg and 32 patients received 300 000 IU. No difference was found in 25-OH-D levels between the two groups at presentation. The mean level of 25-OH-D was higher in the 10 000 IU/kg group at the second week of therapy. There was no difference between the groups at post-treatment weeks 4 and 12. The 25-OH-D was found to be below optimal levels (≥30 ng/mL) in 66.5% and <20 ng/mL in 21.8% of patients at the third month in both groups. None developed hypercalcemia and/or hypercalciuria. Nephrolithiasis was not detected in any patient. This study showed that both doses of stoss therapy used in the treatment of vitamin D insufficiency/deficiency are effective and safe. However, an optimal level of 25-OH-D cannot be maintained for more than three months.

Treatment of Vitamin D Insufficiency in Children and Adolescents with Inflammatory Bowel Disease: A Randomized Clinical Trial Comparing Three Regimens

PubMed Central

Mitchell, Paul D.; Jiang, Hongyu; Kassiff, Sivan; Filip-Dhima, Rajna; DiFabio, Diane; Quinn, Nicolle; Lawton, Rachel C.; Varvaris, Mark; Van Straaten, Stephanie; Gordon, Catherine M.

2012-01-01

Context: Vitamin D insufficiency [serum 25-hydroxyvitamin D (25OHD) concentration less than 20 ng/ml] is prevalent among children with inflammatory bowel disease (IBD), and its treatment has not been studied. Objective: The aim of this study was to compare the efficacy and safety of three vitamin D repletion regimens. Design and Setting: We conducted a randomized, controlled clinical trial from November 2007 to June 2010 at the Clinical and Translational Study Unit of Children's Hospital Boston. The study was not blinded to participants and investigators. Patients: Eligibility criteria included diagnosis of IBD, age 5–21, and serum 25OHD concentration below 20 ng/ml. Seventy-one patients enrolled, 61 completed the trial, and two withdrew due to adverse events. Intervention: Patients received orally for 6 wk: vitamin D2, 2,000 IU daily (arm A, control); vitamin D3, 2,000 IU daily (arm B); vitamin D2, 50,000 IU weekly (arm C); and an age-appropriate calcium supplement. Main Outcome Measure: We measured the change in serum 25OHD concentration (Δ25OHD) (ng/ml). Secondary outcomes included change in serum intact PTH concentration (ΔPTH) (pg/ml) and the adverse event occurrence rate. Results: After 6 wk, Δ25OHD ± se was: 9.3 ± 1.8 (arm A); 16.4 ± 2.0 (arm B); 25.4 ± 2.5 (arm C); P (A vs. C) = 0.0004; P (A vs. B) = 0.03. ΔPTH ± se was −5.6 ± 5.5 (arm A); −0.1 ± 4.2 (arm B); −4.4 ± 3.9 (arm C); P = 0.57. No participant experienced hypercalcemia or hyperphosphatemia, and the prevalence of hypercalciuria did not differ among arms at follow-up. Conclusions: Oral doses of 2,000 IU vitamin D3 daily and 50,000 IU vitamin D2 weekly for 6 wk are superior to 2,000 IU vitamin D2 daily for 6 wk in raising serum 25OHD concentration and are well-tolerated among children and adolescents with IBD. The change in serum PTH concentration did not differ among arms. PMID:22456619

Intestinal Calcium Absorption among Hypercalciuric Patients with or without Calcium Kidney Stones.

PubMed

Vezzoli, Giuseppe; Macrina, Lorenza; Rubinacci, Alessandro; Spotti, Donatella; Arcidiacono, Teresa

2016-08-08

Idiopathic hypercalciuria is a frequent defect in calcium kidney stone formers that is associated with high intestinal calcium absorption and osteopenia. Characteristics distinguishing hypercalciuric stone formers from hypercalciuric patients without kidney stone history (HNSFs) are unknown and were explored in our study. We compared 172 hypercalciuric stone formers with 36 HNSFs retrospectively selected from patients referred to outpatient clinics of the San Raffaele Hospital in Milan from 1998 to 2003. Calcium metabolism and lumbar bone mineral density were analyzed in these patients. A strontium oral load test was performed: strontium was measured in 240-minute urine and serum 30, 60, and 240 minutes after strontium ingestion; serum strontium concentration-time curve and renal strontium clearance were evaluated to estimate absorption and excretion of divalent cations. Serum strontium concentration-time curve (P<0.001) and strontium clearance (4.9±1.3 versus 3.5±2.7 ml/min; P<0.001) were higher in hypercalciuric stone formers than HNSFs, respectively. The serum strontium-time curve was also higher in hypercalciuric stone formers with low bone mineral density (n=42) than in hypercalciuric stone formers with normal bone mineral density (n=130; P=0.03) and HNSFs with low (n=22; P=0.01) or normal bone mineral density (n=14; P=0.02). Strontium clearance was greater in hypercalciuric stone formers with normal bone mineral density (5.3±3.4 ml/min) than in hypercalciuric stone formers and HNSFs with low bone mineral density (3.6±2.5 and 3.1±2.5 ml/min, respectively; P=0.03). Multivariate regression analyses displayed that strontium absorption at 30 minutes was positively associated calcium excretion (P=0.03) and negatively associated with lumbar bone mineral density z score (P=0.001) in hypercalciuric stone formers; furthermore, hypercalciuric patients in the highest quartile of strontium absorption had increased stone production risk (odds ratio, 5.06; 95% confidence interval, 1.2 to 20.9; P=0.03). High calcium absorption in duodenum and jejunum may expose hypercalciuric patients to the risk of stones because of increased postprandial calcium concentrations in urine and tubular fluid. High calcium absorption may identify patients at risk of bone loss among stone formers. Copyright © 2016 by the American Society of Nephrology.

Predictors of renal function in primary hyperparathyroidism.

PubMed

Walker, Marcella D; Nickolas, Thomas; Kepley, Anna; Lee, James A; Zhang, Chiyuan; McMahon, Donald J; Silverberg, Shonni J

2014-05-01

Current guidelines for parathyroidectomy in primary hyperparathyroidism (PHPT) include an estimated glomerular filtration rate (eGFR) less than 60 mL/min per 1.73 m(2). Although the biochemical abnormalities associated with PHPT could impair renal function, there are currently no data examining whether more severe hypercalcemia, hypercalciuria, or nephrolithiasis are associated with chronic kidney disease (CKD) in mild PHPT. This cross-sectional study evaluated predictors of renal function in PHPT. This is a case series of PHPT patients with (eGFR < 60 mL/min per 1.73 m(2)) and without (eGFR ≥ 60 mL/min per 1.73 m(2)) CKD. We studied 114 PHPT patients in a university hospital setting. We identified predictors of renal function using multiple linear regression. eGFR was associated with age, hypertension, antihypertensive medication use, fasting glucose, and 25-hydroxyvitamin D. eGFR was positively rather than negatively associated with several PHPT disease severity indices including history of nephrolithiasis, 24-hour urinary calcium excretion, and 1,25-dihydroxyvitamin D but not serum calcium or PTH levels. An eGFR less than 60 mL/min per 1.73 m(2) was observed in 15% (n = 17), all of whom had stage 3 CKD (eGFR 30-59 mL/min per 1.73 m(2)). Those with CKD were older, had higher 25-hydroxyvitamin D levels and lower 1,25-dihydroxyvitamin D levels, and were more likely to be hypertensive than those without CKD. There were no between-group (<60 vs ≥60 mL/min per 1.73 m(2)) differences in serum calcium, PTH, nephrolithiasis, or meeting surgical criteria other than eGFR. Multiple linear regression indicated that age and diastolic blood pressure were negatively associated with eGFR, whereas serum calcium, kidney stones, and alcohol use were positive predictors. Calculation of eGFR using either the Modification of Diet in Renal Disease or Chronic Kidney Disease Epidemiology Collaboration equation yielded similar results. PHPT patients with stage 3 CKD do not have biochemical or clinical evidence of more severe hyperparathyroidism compared with those without CKD. Traditional risk factors, rather than clinical or biochemical indices of PHPT, are associated with lower eGFR in mild PHPT.

Study protocol for a phase II dose evaluation randomized controlled trial of cholecalciferol in critically ill children with vitamin D deficiency (VITdAL-PICU study).

PubMed

McNally, Dayre; Amrein, Karin; O'Hearn, Katharine; Fergusson, Dean; Geier, Pavel; Henderson, Matt; Khamessan, Ali; Lawson, Margaret L; McIntyre, Lauralyn; Redpath, Stephanie; Weiler, Hope A; Menon, Kusum

2017-01-01

Clinical research has recently demonstrated that vitamin D deficiency (VDD) is highly prevalent in the pediatric intensive care unit (PICU) and associated with worse clinical course. Multiple adult ICU trials have suggested that optimization of vitamin D status through high-dose supplementation may reduce mortality and improve other clinically relevant outcomes; however, there have been no trials of rapid normalization in the PICU setting. The objective of this study is to evaluate the safety and efficacy of an enteral weight-based cholecalciferol loading dose regimen in critically ill children with VDD. The VITdAL-PICU pilot study is designed as a multicenter placebo-controlled phase II dose evaluation pilot randomized controlled trial. We aim to randomize 67 VDD critically ill children using a 2:1 randomization schema to receive loading dose enteral cholecalciferol (10,000 IU/kg, maximum of 400,000 IU) or a placebo solution. Participants, caregivers and outcome assessors will be blinded to allocation. Eligibility criteria include ICU patient, aged 37 weeks to 18 years, expected ICU length of stay more than 48 h, anticipated access to bloodwork at 7 days, and VDD (blood total 25 hydroxyvitamin D < 50 nmol/L). The primary objective is to determine whether the dosing protocol normalizes vitamin D status, defined as a blood total 25(OH)D concentration above 75 nmol/L. Secondary objectives include an examination of the safety of the dosing regimen (e.g. hypercalcemia, hypercalciuria, nephrocalcinosis), measures of vitamin D axis function (e.g. calcitriol levels, immune function), and protocol feasibility (eligibility criteria, protocol deviations, blinding). Despite significant observational literature suggesting VDD to be a modifiable risk factor in the PICU setting, there is no robust clinical trial evidence evaluating the benefits of rapid normalization. This phase II clinical trial will evaluate an innovative weight-based dosing regimen intended to rapidly and safely normalize vitamin D levels in critically ill children. Study findings will be used to inform the design of a multicenter phase III trial evaluating the clinical and economic benefits to rapid normalization. Recruitment for this trial was initiated in January 2016 and is expected to continue until November 30, 2017. Clinicaltrials.gov NCT02452762.

Predictors of Renal Function in Primary Hyperparathyroidism

PubMed Central

Nickolas, Thomas; Kepley, Anna; Lee, James A.; Zhang, Chiyuan; McMahon, Donald J.; Silverberg, Shonni J.

2014-01-01

Context: Current guidelines for parathyroidectomy in primary hyperparathyroidism (PHPT) include an estimated glomerular filtration rate (eGFR) less than 60 mL/min per 1.73 m2. Although the biochemical abnormalities associated with PHPT could impair renal function, there are currently no data examining whether more severe hypercalcemia, hypercalciuria, or nephrolithiasis are associated with chronic kidney disease (CKD) in mild PHPT. Objective: This cross-sectional study evaluated predictors of renal function in PHPT. Design: This is a case series of PHPT patients with (eGFR < 60 mL/min per 1.73 m2) and without (eGFR ≥ 60 mL/min per 1.73 m2) CKD. Settings and Participants: We studied 114 PHPT patients in a university hospital setting. Outcome Measures: We identified predictors of renal function using multiple linear regression. Results: eGFR was associated with age, hypertension, antihypertensive medication use, fasting glucose, and 25-hydroxyvitamin D. eGFR was positively rather than negatively associated with several PHPT disease severity indices including history of nephrolithiasis, 24-hour urinary calcium excretion, and 1,25-dihydroxyvitamin D but not serum calcium or PTH levels. An eGFR less than 60 mL/min per 1.73 m2 was observed in 15% (n = 17), all of whom had stage 3 CKD (eGFR 30–59 mL/min per 1.73 m2). Those with CKD were older, had higher 25-hydroxyvitamin D levels and lower 1,25-dihydroxyvitamin D levels, and were more likely to be hypertensive than those without CKD. There were no between-group (<60 vs ≥60 mL/min per 1.73 m2) differences in serum calcium, PTH, nephrolithiasis, or meeting surgical criteria other than eGFR. Multiple linear regression indicated that age and diastolic blood pressure were negatively associated with eGFR, whereas serum calcium, kidney stones, and alcohol use were positive predictors. Calculation of eGFR using either the Modification of Diet in Renal Disease or Chronic Kidney Disease Epidemiology Collaboration equation yielded similar results. Conclusions: PHPT patients with stage 3 CKD do not have biochemical or clinical evidence of more severe hyperparathyroidism compared with those without CKD. Traditional risk factors, rather than clinical or biochemical indices of PHPT, are associated with lower eGFR in mild PHPT. PMID:24527717

Identification of a G‐Protein Subunit‐α11 Gain‐of‐Function Mutation, Val340Met, in a Family With Autosomal Dominant Hypocalcemia Type 2 (ADH2)

PubMed Central

Piret, Sian E; Gorvin, Caroline M; Pagnamenta, Alistair T; Howles, Sarah A; Cranston, Treena; Rust, Nigel; Nesbit, M Andrew; Glaser, Ben; Taylor, Jenny C; Buchs, Andreas E; Hannan, Fadil M

2016-01-01

ABSTRACT Autosomal dominant hypocalcemia (ADH) is characterized by hypocalcemia, inappropriately low serum parathyroid hormone concentrations and hypercalciuria. ADH is genetically heterogeneous with ADH type 1 (ADH1), the predominant form, being caused by germline gain‐of‐function mutations of the G‐protein coupled calcium‐sensing receptor (CaSR), and ADH2 caused by germline gain‐of‐function mutations of G‐protein subunit α‐11 (Gα11). To date Gα11 mutations causing ADH2 have been reported in only five probands. We investigated a multigenerational nonconsanguineous family, from Iran, with ADH and keratoconus which are not known to be associated, for causative mutations by whole‐exome sequencing in two individuals with hypoparathyroidism, of whom one also had keratoconus, followed by cosegregation analysis of variants. This identified a novel heterozygous germline Val340Met Gα11 mutation in both individuals, and this was also present in the other two relatives with hypocalcemia that were tested. Three‐dimensional modeling revealed the Val340Met mutation to likely alter the conformation of the C‐terminal α5 helix, which may affect G‐protein coupled receptor binding and G‐protein activation. In vitro functional expression of wild‐type (Val340) and mutant (Met340) Gα11 proteins in HEK293 cells stably expressing the CaSR, demonstrated that the intracellular calcium responses following stimulation with extracellular calcium, of the mutant Met340 Gα11 led to a leftward shift of the concentration‐response curve with a significantly (p < 0.0001) reduced mean half‐maximal concentration (EC50) value of 2.44 mM (95% CI, 2.31 to 2.77 mM) when compared to the wild‐type EC50 of 3.14 mM (95% CI, 3.03 to 3.26 mM), consistent with a gain‐of‐function mutation. A novel His403Gln variant in transforming growth factor, beta‐induced (TGFBI), that may be causing keratoconus was also identified, indicating likely digenic inheritance of keratoconus and ADH2 in this family. In conclusion, our identification of a novel germline gain‐of‐function Gα11 mutation, Val340Met, causing ADH2 demonstrates the importance of the Gα11 C‐terminal region for G‐protein function and CaSR signal transduction. © 2016 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR). PMID:26818911

300,000 IU or 600,000 IU of oral vitamin D3 for treatment of nutritional rickets: a randomized controlled trial.

PubMed

Mittal, Hema; Rai, Sunita; Shah, Dheeraj; Madhu, S V; Mehrotra, Gopesh; Malhotra, Rajeev Kumar; Gupta, Piyush

2014-04-01

To evaluate the non-inferiority of a lower therapeutic dose (300,000 IU) in comparison to standard dose (600,000) IU of Vitamin D for increasing serum 25(OH) D levels and achieving radiological recovery in nutritional rickets. Randomized, open-labeled, controlled trial. Tertiary care hospital. 76 children (median age 12 mo) with clinical and radiologically confirmed rickets. Oral vitamin D3 as 300,000 IU (Group 1; n=38) or 600,000 IU (Group 2; n=38) in a single day. Primary: Serum 25(OH)D, 12 weeks after administration of vitamin D3; Secondary: Radiological healing and serum parathormone at 12 weeks; and clinical and biochemical adverse effects. Serum 25(OH)D levels [geometric mean (95% CI)] increased significantly from baseline to 12 weeks after therapy in both the groups [Group 1: 7.58 (5.50–10.44) to 16.06 (12.71– 20.29) ng/mL, P<0.001]; Group 2: 6.57 (4.66–9.25) to 17.60 (13.71–22.60, P<0.001]. The adjusted ratio of geometric mean serum 25(OH)D levels at 12 weeks between the groups (taking baseline value as co-variate) was 0.91 (95% CI: 0.65–1.29). Radiological healing occurred in all children by 12 weeks. Both groups demonstrated significant (P<0.05) and comparable fall in the serum parathormone and alkaline phosphatase levels at 12 weeks. Relative change [ratio of geometric mean (95% CI)] in serum PTH and alkaline phosphatase, 12 weeks after therapy, were 0.98 (0.7–1.47) and 0.92 (0.72–1.19), respectively. The serum 25(OH)D levels were deficient (<20 ng/mL) in 63% (38/60) children after 12 weeks of intervention [Group 1: 20/32 (62.5%); Group 2: 18/28 (64.3%)]. No major clinical adverse effects were noticed in any of the children. Hypercalcemia was documented in 2 children at 4 weeks (1 in each Group) and 3 children at 12 weeks (1 in Group 1 and 2 in Group 2). None of the participants had hypercalciuria or hypervitaminosis D. A dose of 300,000 IU of vitamin D3 is comparable to 600,000 IU, administered orally, over a single day, for treating rickets in under-five children although there is an unacceptably high risk of hypercalcemia in both groups. None of the regime is effective in normalization of vitamin D status in majority of patients, 3 months after administering the therapeutic dose.

Multiple sclerosis and nephrolithiasis: a matched-case comparative study.

PubMed

Ganesan, Vishnu; Chen, Wen Min; Jain, Rajat; De, Shubha; Monga, Manoj

2017-06-01

To compare stone composition and serum/urine biochemistries in stone formers with multiple sclerosis (MS) against stone formers without MS and to examine the association between mobility, methods of bladder emptying, and stone formation. In this retrospective case-control study, we identified patients diagnosed with MS and kidney stone disease who were seen at our institution between 2001 and 2016. For the first part of the study, up to two controls (stone formers without a history of MS) were identified for each case and matched on age, body mass index, and sex. For the second part of this study, matched controls (MS patients without a history of stones) were identified in a 1:1 ratio in a similar fashion. Results of 24-h urine biochemistry studies, stone compositions, serum laboratory measures, medications, history of stone surgeries, mobility, and method of bladder emptying were collected. In all, 587 patients were identified who had both MS and a history of stone disease. Of these, 118 patients had a stone composition available. When compared to matched controls, patients with MS were significantly more likely to have calcium phosphate stones (42% vs 15%, P < 0.001) and struvite stones (8% vs 3%, P = 0.03) and less likely to have calcium oxalate monohydrate stones (39% vs 64%, P < 0.001). Among those patients with a composition available, those with MS were more likely to have undergone a percutaneous nephrolithotomy (PCNL; 25% vs 12%, P = 0.005) or a cystolithopaxy (16% vs 3%, P < 0.001) compared to their matched controls. In all, 61 patients had a complete 24-h urinary stone panel. There were no significant differences in urinary pH, volume, creatinine, calcium, citrate, oxalate, sodium, and uric acid as well as rates of hypocitraturia, hyperoxaluria, hypercalciuria, and hyperuricosuria among patients with MS. Use of intermittent straight catheterisation [ISC; odds ratio (OR) 3.50, 95% confidence interval (CI) 1.89-6.47]; P < 0.001] or an indwelling catheter (OR 9.78, 95% CI 4.81-19.88; P < 0.001) for bladder emptying was significantly associated with stone disease. There was no association between level of mobility and stone disease (P = 0.10). Similar to findings seen in patients with spinal cord injuries, patients with MS have a high incidence of calcium phosphate stones and struvite stones when compared with matched controls. Additionally, they were more likely to undergo PCNL. The method of bladder management appears to be a risk factor in the development of stone disease. These findings suggest the importance of prompt treatment of urinary tract infections in this population and delay the use of ISC, suprapubic tube, or an indwelling Foley, when possible. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

Treatment of low bone density in young people with cystic fibrosis: a multicentre, prospective, open-label observational study of calcium and calcifediol followed by a randomised placebo-controlled trial of alendronate.

PubMed

Bianchi, Maria Luisa; Colombo, Carla; Assael, Baroukh M; Dubini, Antonella; Lombardo, Mariangela; Quattrucci, Serena; Bella, Sergio; Collura, Mirella; Messore, Barbara; Raia, Valeria; Poli, Furio; Bini, Rita; Albanese, Carlina V; De Rose, Virginia; Costantini, Diana; Romano, Giovanna; Pustorino, Elena; Magazzù, Giuseppe; Bertasi, Serenella; Lucidi, Vincenzina; Traverso, Gabriella; Coruzzo, Anna; Grzejdziak, Amelia D

2013-07-01

Long-term complications of cystic fibrosis include osteoporosis and fragility fractures, but few data are available about effective treatment strategies, especially in young patients. We investigated treatment of low bone mineral density in children, adolescents, and young adults with cystic fibrosis. We did a multicentre trial in two phases. We enrolled patients aged 5-30 years with cystic fibrosis and low bone mineral density, from ten cystic fibrosis regional centres in Italy. The first phase was an open-label, 12-month observational study of the effect of adequate calcium intake plus calcifediol. The second phase was a 12-month, double-blind, randomised, placebo-controlled, parallel group study of the efficacy and safety of oral alendronate in patients whose bone mineral apparent density had not increased by 5% or more by the end of the observational phase. Patients were randomly assigned to either alendronate or placebo. Both patients and investigators were masked to treatment assignment. We used dual x-ray absorptiometry at baseline and every 6 months thereafter, corrected for body size, to assess lumbar spine bone mineral apparent density. We assessed bone turnover markers and other laboratory parameters every 3-6 months. The primary endpoint was mean increase of lumbar spine bone mineral apparent density, assessed in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT01812551. We screened 540 patients and enrolled 171 (mean age 13·8 years, SD 5·9, range 5-30). In the observational phase, treatment with calcium and calcifediol increased bone mineral apparent density by 5% or more in 43 patients (25%). 128 patients entered the randomised phase. Bone mineral apparent density increased by 16·3% in the alendronate group (n=65) versus 3·1% in the placebo group (n=63; p=0·0010). 19 of 57 young people (33·3%) receiving alendronate attained a normal-for-age bone mineral apparent density Z score. In the observational phase, five patients had moderate episodes of hypercalciuria, which resolved after short interruption of calcifediol treatment. During the randomised phase, one patient taking alendronate had mild fever versus none in the placebo group; treatment groups did not differ significantly for other adverse events. Correct calcium intake plus calcifediol can improve bone mineral density in some young patients with cystic fibrosis. In those who do not respond to calcium and calcifediol alone, alendronate can safely and effectively increase bone mineral density. Telethon Foundation (Italy). Copyright © 2013 Elsevier Ltd. All rights reserved.

Renal stone risk in a simulated microgravity environment: impact of treadmill exercise with lower body negative pressure.

PubMed

Monga, Manoj; Macias, Brandon; Groppo, Eli; Kostelec, Monica; Hargens, Alan

2006-07-01

Prolonged exposure to microgravity during spaceflight causes metabolic changes that increase the risk of renal stone formation. Studies during the Gemini, Apollo, Skylab and Shuttle missions demonstrated alterations in renal function, fluid homeostasis and bone resorption that result in increased urinary supersaturation of calcium oxalate, brushite, sodium urate and uric acid. Developing countermeasures to increased urinary supersaturation is an important priority as the duration of space missions increases. A total of 11 sets of identical twins remained on 6-degree head down, tilt bed rest for 30 days to simulate prolonged microgravity. One twin per pair was randomly selected to exercise while supine in a lower body negative pressure chamber 6 days weekly for 40 minutes, followed by 5 minutes of resting lower body negative pressure at 50 mm Hg. The other twin served as a nonexercise control. Pressure in the exercise lower body negative pressure chamber (52 to 63 mm Hg) was adjusted to produce footward forces equivalent to those for upright running on Earth at 1.0 to 1.2 x body weight. Pre-bed rest urinary stone risk profiles were done elsewhere after 5 days of a standardized diet, consisting of 170 mEq sodium, 1,000 mg calcium, 0.8 gm/kg animal protein and 2,500 kcal, and then throughout the bed rest and recovery phases of the protocol. A significant increase in urinary calcium after just 1 week of bed rest was noted in the nonexercise control group (p = 0.001). However, no such increase was noted in the exercise group. Brushite supersaturation increased significantly from bed rest in each group, although the increase was significantly higher in the nonexercise control group than in the exercise group (p = 0.006). Calcium oxalate supersaturation increased during bed rest in the exercise group (p = 0.004). It trended toward a higher level in the nonexercise control group, although this did not achieve significance (p = 0.055) Mean urine volume +/- SD was significantly higher in the nonexercise control group than in the exercise group at bed rest week 2 and at week 3 (2.01 +/- 0.21 vs 1.63 0.18 l and 2.03 +/- 0.22 vs 1.81 +/- 0.20, respectively). Urinary pH was significantly higher in the nonexercise control group than in the exercise group at week 1 and week 3 (6.62 +/- 0.7 vs 6.49 +/- 0.5 and 6.58 +/- 0.6 vs 6.49 +/- 0.8, respectively, p = 0.01). Bed rest significantly alters the urinary environment to favor calculous formation. Lower body negative pressure chamber treadmill exercise offers some protection against increases in stone risk during simulated microgravity, particularly with regard to the risks of hypercalciuria and brushite stone formation. The use of lower body negative pressure to augment aerobic exercise in space may decrease the risk of stone formation in astronauts. Adjunct measures, including aggressive hydration and alkalinization therapy, should be considered.

Bisphosphonate as a Countermeasure to Space Flight-Induced Bone Loss

NASA Technical Reports Server (NTRS)

Spector, Elisabeth; LeBlanc, A.; Sibonga, J.; Matsumoto, T.; Jones, J.; Smith, S. M.; Shackelford, L.; Shapiro, J.; Lang, T.; Evans, H.;

Dietary treatment of urinary risk factors for renal stone formation. A review of CLU Working Group.

PubMed

Prezioso, Domenico; Strazzullo, Pasquale; Lotti, Tullio; Bianchi, Giampaolo; Borghi, Loris; Caione, Paolo; Carini, Marco; Caudarella, Renata; Ferraro, Manuel; Gambaro, Giovanni; Gelosa, Marco; Guttilla, Andrea; Illiano, Ester; Martino, Marangella; Meschi, Tiziana; Messa, Piergiorgio; Miano, Roberto; Napodano, Giorgio; Nouvenne, Antonio; Rendina, Domenico; Rocco, Francesco; Rosa, Marco; Sanseverino, Roberto; Salerno, Annamaria; Spatafora, Sebastiano; Tasca, Andrea; Ticinesi, Andrea; Travaglini, Fabrizio; Trinchieri, Alberto; Vespasiani, Giuseppe; Zattoni, Filiberto

2015-07-07

Diet interventions may reduce the risk of urinary stone formation and its recurrence, but there is no conclusive consensus in the literature regarding the effectiveness of dietary interventions and recommendations about specific diets for patients with urinary calculi. The aim of this study was to review the studies reporting the effects of different dietary interventions for the modification of urinary risk factors in patients with urinary stone disease. A systematic search of the Pubmed database literature up to July 1, 2014 for studies on dietary treatment of urinary risk factors for urinary stone formation was conducted according to a methodology developed a priori. Studies were screened by titles and abstracts for eligibility. Data were extracted using a standardized form and the quality of evidence was assessed. Evidence from the selected studies were used to form evidence-based guideline statements. In the absence of sufficient evidence, additional statements were developed as expert opinions. General measures: Each patient with nephrolithiasis should undertake appropriate evaluation according to the knowledge of the calculus composition. Regardless of the underlying cause of the stone disease, a mainstay of conservative management is the forced increase in fluid intake to achieve a daily urine output of 2 liters. HYPERCALCIURIA: Dietary calcium restriction is not recommended for stone formers with nephrolithiasis. Diets with a calcium content ≥ 1 g/day (and low protein-low sodium) could be protective against the risk of stone formation in hypercalciuric stone forming adults. Moderate dietary salt restriction is useful in limiting urinary calcium excretion and thus may be helpful for primary and secondary prevention of nephrolithiasis. A low-normal protein intake decrease calciuria and could be useful in stone prevention and preservation of bone mass. Omega-3 fatty acids and bran of different origin decreases calciuria, but their impact on the urinary stone risk profile is uncertain. Sports beverage do not affect the urinary stone risk profile. HYPEROXALURIA: A diet low in oxalate and/or a calcium intake normal to high (800-1200 mg/day for adults) reduce the urinary excretion of oxalate, conversely a diet rich in oxalates and/or a diet low in calcium increase urinary oxalate. A restriction in protein intake may reduce the urinary excretion of oxalate although a vegetarian diet may lead to an increase in urinary oxalate. Adding bran to a diet low in oxalate cancels its effect of reducing urinary oxalate. Conversely, the addition of supplements of fruit and vegetables to a mixed diet does not involve an increased excretion of oxalate in the urine. The intake of pyridoxine reduces the excretion of oxalate. HYPERURICOSURIA: In patients with renal calcium stones the decrease of the urinary excretion of uric acid after restriction of dietary protein and purine is suggested although not clearly demonstrated. HYPOCITRATURIA: The administration of alkaline-citrates salts is recommended for the medical treatment of renal stone-formers with hypocitraturia, although compliance to this treatment is limited by gastrointestinal side effects and costs. Increased intake of fruit and vegetables (excluding those with high oxalate content) increases citrate excretion and involves a significant protection against the risk of stone formation. Citrus (lemons, oranges, grapefruit, and lime) and non citrus fruits (melon) are natural sources of dietary citrate, and several studies have shown the potential of these fruits and/or their juices in raising urine citrate levels. There are enought basis to advice an adequate fluid intake also in children. Moderate dietary salt restriction and implementation of potassium intake are useful in limiting urinary calcium excretion whereas dietary calcium restriction is not recommended for children with nephrolithiasis. It seems reasonable to advice a balanced consumption of fruit and vegetables and a low consumption of chocolate and cola according to general nutritional guidelines, although no studies have assessed in pediatric stone formers the effect of fruit and vegetables supplementation on urinary citrate and the effects of chocolate and cola restriction on urinary oxalate in pediatric stone formers. Despite the low level of scientific evidence, a low-protein (< 20 g/day) low-salt (< 2 g/day) diet with high hydration (> 3 liters/day) is strongly advised in children with cystinuria. ELDERLY: In older patients dietary counseling for renal stone prevention has to consider some particular aspects of aging. A restriction of sodium intake in association with a higher intake of potassium, magnesium and citrate is advisable in order to reduce urinary risk factors for stone formation but also to prevent the loss of bone mass and the incidence of hypertension, although more hemodynamic sensitivity to sodium intake and decreased renal function of the elderly have to be considered. A diet rich in calcium (1200 mg/day) is useful to maintain skeletal wellness and to prevent kidney stones although an higher supplementation could involve an increase of risk for both the formation of kidney stones and cardiovascular diseases. A lower content of animal protein in association to an higher intake of plant products decrease the acid load and the excretion of uric acid has no particular contraindications in the elderly patients, although overall nutritional status has to be preserved.