Urinary Calcium Research Articles

A novel mouse model for familial hypocalciuric hypercalcemia (FHH1) reveals PTH-dependent and independent CaSR defects

The Calcium-sensing receptor (CaSR) senses extracellular calcium, regulates parathyroid hormone (PTH) secretion, and has additional functions in various organs related to systemic and local calcium and mineral homeostasis. Familial hypocalciuric hypercalcemia type I (FHH1) is caused by heterozygous loss-of-function mutations in the CaSR gene, and is characterized by the combination of hypercalcemia, hypocalciuria, normal to elevated PTH, and facultatively hypermagnesemia and mild bone mineralization defects. To date, only heterozygous Casr null mice have been available as model for FHH1. Here we present a novel mouse FHH1 model identified in a large ENU-screen that carries an c.2579 T > A (p.Ile859Asn) variant in the Casr gene (CasrBCH002 mice). In order to dissect direct effects of the genetic variant from PTH-dependent effects, we crossed CasrBCH002 mice with PTH deficient mice. Heterozygous CasrBCH002 mice were fertile, had normal growth and body weight, were hypercalcemic and hypermagnesemic with inappropriately normal PTH levels and urinary calcium excretion replicating some features of FHH1. Hypercalcemia and hypermagnesemia were independent from PTH and correlated with higher expression of claudin 16 and 19 in kidneys. Likewise, reduced expression of the renal TRPM6 channel in CasrBCH002 mice was not dependent on PTH. In bone, mutations in Casr rescued the bone phenotype observed in Pth null mice by increasing osteoclast numbers and improving the columnar pattern of chondrocytes in the growth zone. In summary, CasrBCH002 mice represent a new model to study FHH1 and our results indicate that only a part of the phenotype is driven by PTH.

In vivo treatment with calcilytic of CaSR knock-in mice ameliorates renal phenotype reversing downregulation of the vasopressin-AQP2 pathway.

High concentrations of urinary calcium counteract vasopressin action via the activation of the Calcium-Sensing Receptor (CaSR) expressed in the luminal membrane of the collecting duct cells, which impairs the trafficking of aquaporin-2 (AQP2). In line with these findings, we provide evidence that, with respect to wild-type mice, CaSR knock-in (KI) mice mimicking autosomal dominant hypocalcaemia, displaya significant decrease in the total content of AQP2 associated with significantly higher levels of AQP2 phosphorylation at Ser261, a phosphorylation site involved in AQP2 degradation. Interestingly, KI mice also had significantly higher levels of phosphorylated p38MAPK, a downstream effector of CaSR and known to phosphorylate AQP2 at Ser261. Moreover, ATF1 phosphorylated at Ser63, a transcription factor downstream of p38MAPK, was significantly higher in KI. In addition, KI mice had significantly higher levels of AQP2-targeting miRNA137 consistent with a post-transcriptional downregulation of AQP2. In vivo treatment of KI mice with the calcilytic JTT-305, a CaSR antagonist, increased AQP2 expression and reduced AQP2-targeting miRNA137 levels in KI mice.Together, these results provide direct evidence for a critical role of CaSR in impairing both short-term vasopressin response by increasing AQP2-pS261, as well as AQP2 abundance, via the p38MAPK-ATF1-miR137 pathway. KEY POINTS: Calcium-Sensing Receptor (CaSR) activating mutations are the main cause of autosomal dominant hypocalcaemia (ADH) characterized by inappropriate renal calcium excretion leading to hypocalcaemia and hypercalciuria. Current treatments of ADH patients with parathyroid hormone, although improving hypocalcaemia, do not improve hypercalciuria or nephrocalcinosis. In vivo treatment with calcilytic JTT-305/MK-5442 ameliorates most of the ADH phenotypes of the CaSR knock-in mice including hypercalciuria or nephrocalcinosis and reverses the downregulation of the vasopressin-sensitive aquaporin-2 (AQP2) expression, providing direct evidence for a critical role of CaSR in impairing vasopressin response. The beneficial effect of calcilytic in reducing the risk of renal calcification may occur in a parathyroid hormone-independent action through vasopressin-dependent inhibition of cAMP synthesis in the thick ascending limb and in the collecting duct. The amelioration of most of the abnormalities in calcium metabolism including hypercalciuria, renal calcification, and AQP2-mediated osmotic water reabsorption makes calcilytic a good candidate as a novel therapeutic agent for ADH.

An update on clinical presentation and responses to therapy of patients with hereditary hypophosphatemic rickets with hypercalciuria (HHRH)

Pathogenic variants in solute carrier family 34, member 3 (SLC34A3), the gene encoding the sodium-dependent phosphate cotransporter 2c (NPT2c), cause hereditary hypophosphatemic rickets with hypercalciuria (HHRH). Here, we report a pooled analysis of clinical and laboratory records of 304 individuals from 145 kindreds, including 20 previously unreported HHRH kindreds, in which two novel SLC34A3 pathogenic variants were identified. Compound heterozygous/homozygous carriers show above 90% penetrance for kidney and bone phenotypes. The biochemical phenotype for heterozygous carriers is intermediate with decreased serum phosphate, tubular reabsorption of phosphate (TRP (%)), fibroblast growth factor 23, and intact parathyroid hormone, but increased serum 1,25-dihydroxy vitamin D, and urine calcium excretion causing idiopathic hypercalciuria in 38%, with bone phenotypes still observed in 23% of patients. Oral phosphate supplementation is the current standard of care, which typically normalizes serum phosphate. However, although in more than half of individuals this therapy achieves correction of hypophosphatemia it fails to resolve the other outcomes. The American College of Medical Genetics score correlated with functional analysis of frequent SLC34A3 pathogenic variants in vitro and baseline disease severity. The number of mutant alleles and baseline TRP (%) were identified as predictors for kidney and bone phenotypes, baseline TRP (%) furthermore predicted response to therapy. Certain SLC34A3/NPT2c pathogenic variants can be identified with partial responses to therapy, whereas with some overlap, others present only with kidney phenotypes and a third group present only with bone phenotypes. Thus, our report highlights important novel clinical aspects of HHRH and heterozygous carriers, raises awareness to this rare group of disorders and can be a foundation for future studies urgently needed to guide therapy of HHRH.

Preliminary study of the role of nanobacteria in the formation of renal stones in experimental rats and its mechanism.

The aim of the study was to study the role of nanobacteria in the formation of renal calculi and the underlying mechanism. A total of 90 clean Wistar male rats were randomly divided into a negative control group, an experimental group, and an interference group. From the end of the first week of modelling, 10 consecutive times once a week, 3 rats in each group were randomly selected to measure the biochemical blood markers and urine metabolism. After sacrifice, the formation of kidney stones was assessed by observing the ultrastructure of the kidney by electron microscopy and pathohistology. Finally, the expression of calcium-sensitive receptor (CaSR) and claudin-14 protein in the kidney tissue was examined by western blotting. Compared with the control group, the gross structure of the kidney was changed in the model group. At the fourth week of modelling, the rats in the nanobacteria group had significantly enlarged kidneys and increased kidney-to-body ratio, and the difference had statistical significance (p < 0.05). The colour of the kidney profile was dark, the structure of the skin pulp was less clear, and the accumulation of yellowish particles was observed at the junction of the cortical pulp. The creatinine, uric acid, urea nitrogen, and urinary calcium of the rats in the nanobacteria group began to increase at the third week, and the difference between the third and eighth week had statistical significance (p < 0.05). However, the difference between the 3 groups had no statistical significance after the eighth week. At the fourth week, we observed the formation of calculi, which were mainly distributed in the renal tubules and surrounding tissues. The kidney stone formation rate was 52.4% in the nanobacteria group and 27.8% in the interference group, and the difference had statistical significance (p < 0.05). Ultrastructure observations revealed that from the fourth week, the renal tissues in the nanobacteria group showed expanded renal tubules, swollen renal tubular epithelium, granular degeneration, shedding and lymphocyte infiltration of renal tubular epithelial cells, and a small amount of calcium salt crystals in renal tubules. At the third week, the expression of CaSR and Claudin-14 protein in the nanobacteria group increased, and the difference had statistical significance (p < 0.05). The expression of CaSR and Claudin-14 was positively correlated with urinary calcium (p < 0.05). The formation of renal calculi began in the fourth week after the model was established, and the crystals were mostly located in the renal tubules. During the formation of renal calculi, the renal tubular epithelial cells were damaged, showing granular degeneration and small amounts of calcium salt crystals, accompanied by a few renal tubules beginning to expand and epithelial swelling, granular degeneration, necrosis and shedding of renal tubular epithelial cells, lymphocyte infiltration in the renal interstitium, and small amounts of calcium salt crystals in the renal tubules, which aggravated with time. The serum creatinine, serum uric acid, urea nitrogen, and urinary calcium levels increased with time from the third week and returned to normal after the eighth week. The expression of CaSR and Claudin-14 protein was upregulated and positively correlated with the 24-h urinary calcium excretion value.

Risk factors for hip and vertebral fractures in chronic kidney disease: the CRIC study.

Fracture risk is high in chronic kidney disease (CKD) and underlying pathophysiology and risk factors may differ from the general population. In a cohort study of 3939 participants in the chronic renal insufficiency cohort (CRIC), we used Cox regression to test associations of putative risk factors with the composite of first hip or vertebral fracture assessed using hospital discharge codes. Mean age was 58years, 45% were female, 42% were Black, and 13% were Hispanic. There were 82 hip and 24 vertebral fractures over a mean (SD) 11.1 (4.8) years (2.4 events per 1000 person-years [95% CI: 2.0, 2.9]). Measured at baseline, diabetes, lower body mass index (BMI), steroid use, proteinuria, and elevated parathyroid hormone (PTH) were each associated with fracture risk after adjusting for covariates. Lower time-updated estimated glomerular filtration rate (eGFR) was associated with fractures (HR 1.20 per 10mL/min/1.73m2 lower eGFR; 95% CI: 1.04, 1.38) as were lower time-updated serum calcium and bicarbonate concentrations. Among time-updated categories of kidney function, hazard ratios (95% CI) for incident fracture were 4.53 (1.77, 11.60) for kidney failure treated with dialysis and 2.48 (0.86, 7.14) for post-kidney transplantation, compared with eGFR ≥60. Proton pump inhibitor use, dietary calcium intake, measures of vitamin D status, serum phosphate, urine calcium and phosphate, and plasma fibroblast growth factor-23 were not associated with fracture risk. In conclusion, lower eGFR in CKD is associated with higher fracture risk, which was highest in kidney failure. Diabetes, lower BMI, steroid use, proteinuria, higher serum concentrations of PTH, and lower calcium and bicarbonate concentrations were associated with fractures and may be modifiable risk factors.

Inherited Fanconi renotubular syndromes: unveiling the intricacies of hypophosphatemic rickets/osteomalacia.

Fanconi renotubular syndromes (FRTS) are a rare group of inherited phosphaturic disorders with limited Indian as well as global data on this condition. Here, we describe the experience of a single Endocrinology center from Western India on FRTS. Comprehensive clinical, biochemical, radiological, management, and genetic details of FRTS patients managed between 2010 and 2023 were collected and analyzed. FRTS probands had mutations (eight novel) in six genes [CLCN5(n = 4), SLC2A2(n = 2), GATM, EHHADH, HNF4A,andOCRL(1 each)].Among 15 FRTS patients (11 families), rickets/osteomalaciawas the most common (n = 14) presentation with wide inter- and intra-familial phenotypic variability. Delayed diagnosis (median: 8.8years), initial misdiagnosis (8/11 probands), and syndrome-specific discriminatory features (8/11 probands) were commonly seen. Hypophosphatemia, elevated alkaline phosphatase, normal parathyroid hormone (median: 36 pg/ml), high-normal/elevated 1,25(OH)2D (median: 152 pg/ml), hypercalciuria (median spot urinary calcium to creatinine ratio: 0.32), and variable proximal tubular dysfunction(s) were observed. Elevated C-terminal fibroblast growth factor 23 in two probands was misleading, till the genetic diagnosis was reached. Novel observations in our FRTS cohort were preserved renal function (till sixth decade) and enthesopathy in FRTS1 and FRTS3 families, respectively. Our findings underscore frequent under- and misdiagnosis of FRTS; hence, a high index of suspicion for FRTS in phosphopenic rickets/osteomalacia, with early consideration of genetic testing is essential to ensure timely diagnosis of FRTS. The novel variants and phenotypic manifestations described here expand the disease spectrum of FRTS.

Safety and efficacy of a polyherbal formulation from traditional Persian medicine in patients with calcium kidney stones: A randomized, double-blinded clinical trial.

10%-15% of the world's population suffers from kidney stones. Nearly 50% increase was observed in diagnosing and treating nephrolithiasis in the last decades. Effective medical treatment for the disease is not yet well established. Moreover, there is an increasing global demand to manage diseases using complementary and alternative medicine. This study aimed to formulate and assess the safety and efficacy of a multi-ingredient formulation from traditional Persian medicine (TPM) known as Mofatet powder in patients suffering from calcium kidney stones. The aqueous extract of Mofatet powder was prepared, freeze-dried, and formulated as capsules. 26 patients in the drug group and 25 patients in the placebo group used 500 mg capsules of the drug/placebo twice daily for 5 weeks. Ultrasonography/kidney, ureter and bladder imaging, urine analysis, and biochemical parameters were evaluated before and after the intervention. The imaging results showed a 60.73% decrease (P < 0.001) in stone size in the drug group. Moreover, the urinary calcium decreased (P = 0.02) and the urinary magnesium increased (P < 0.001) in the drug group. No remarkable changes were observed in the placebo group in these parameters. No significant effect was observed in aspartate transaminase, alanine transaminase, serum creatinine, and blood urea nitrogen levels in none of the groups. This study suggests that Mofatet powder was effective in reducing calcium kidney stones size with no potential nephro/hepatotoxicity. After confirming these results in larger clinical trials with longer duration, this formulation can be considered a treatment for nephrolithiasis.

REVIEW OF THE PHYTOTHERAPY FOR NEPHROLITHIASIS

Nephrolithiasis (kidney stone) cases have a prevalence ranging from 1% to 13%. The disease not only hampers kidney function but also elevates the risk of chronic kidney diseases. The pathophysiology of nephrolithiasis is closely linked to elevated concentrations of calcium, oxalate, and/or uric acid in the urine. Pharmacotherapy to manage nephrolithiasis includes thiazide diuretics, allopurinol, citrate supplements, and alpha-blockers that have been prescribed to relieve symptoms. In addition, there is growing interest in exploring the potential of phytotherapy. This review aims to identify suitable phytotherapy approaches by examining relevant articles on nephrolithiasis. The research methodology involved searching PubMed articles using the keywords of (("Plant Extracts") AND ("Nephrolithiasis")) OR ("Ureterolithiasis"). The articles obtained from the initial search were n =123. 2 authors screened articles for their eligibility. The inclusion criteria were limited to articles written in English, topics related to nephrolithiasis and not other kidney diseases, the botanical names of the plants and the method of extraction are clearly described, complete studies with clear descriptions regarding the methods and results, not synthetic drugs, and not involving medical instruments or laser to remove the stones. Articles included in the review were n = 17. Water and hydro-alcohol were the solvents used to extract the plants. Twenty-two plants have confirmed their anti-nephrolithiasis activity, and nine articles described the assay by in vivo study, two by in vitro study, three by both in vitro and in vivo study, and only one article mentioned a study in humans by a randomized-control trial on a mixture of herbs. It is concluded that Rhizoma alismatis, Poria cocos, Polyporus umbellatus, Atractylodis macrocephalae, and Cinnamomi Cassiae prepared as a mixture in the Wu-Ling-San formula have a potential therapeutic effect on nephrolithiasis, as this formula has been studied in humans.

The daily calcium profile in patients with chronic hypoparathyroidism depending on different 25(OH) vitamin D level

BACKGROUND: Chronic hypoparathyroidism is a relatively rare disease, which usually treated active forms of vitamin D and oral calcium supplements. Supplementation with native vitamin D can be useful both for achieving «non-skeletal» effects of vitamin D and for a more stable serum calcium profile.AIM: The aim of this study was to estimate the daily serum calcium and 24-hour urine calcium levels depending on different 25(OH) vitamin D values in patients with chronic hypoparathyroidism on treatment of active forms of vitamin D and calcium supplements.MATERIALS AND METHODS: Forty patients with chronic hypoparathyroidism were involved in the study. All patients were divided in two groups, matched on sex and age, according to the median level of 25(OH) vitamin D in the total group.RESULTS: There were no significant differences between groups by total, albumin-adjusted serum calcium levels and urine calcium excretion. Patients with serum 25(ОН) vitamin D level ≥ 35 ng/ml had significant tendency to achieve more often the target levels of total serum calcium during the day (128 vs. 149 measurements during the day, p=0.049, χ2). However, this tendency disappeared for albumin-adjusted serum calcium levels (p=0.517, χ2). There frequency of hypercalcemia by albumin-adjusted serum calcium in the group of patients with 25(ОН) vitamin D ≥ 35 ng/ml (p=0.006, χ2) was significantly lower, but not for total serum calcium (a trend, p=0.042, χ2). As regards hypocalcemia, there were no significant differences by albumin-adjusted serum calcium (p=0.581, χ2) and it tends to lower frequency by total serum calcium (p=0.023, χ2).CONCLUSION: The additional administration of native vitamin D in patients with chronic hypoparathyroidism may have some advantages, related to the general concept of worldwide vitamin D deficiency and better disease control.

Contrasting Response of Urine Stone Risk to Medical Treatment in Calcium Oxalate versus Calcium Phosphate Stone Formers.

Randomized controlled trials have shown that both thiazide diuretics and potassium citrate (K-Cit) can prevent calcium stone recurrence, but most participants formed calcium oxalate stones (CaOx). While thiazides are expected to lower stone risk for calcium phosphate (CaP) stones, the effect of K-Cit on risk for CaP stones is unclear. To study the impact of common calcium stones treatments, we analyzed the 24-hour urines of CaOx and CaP stone formers (SF) by 4 treatment types: Lifestyle, K-Cit, Thiazide, or Both medications. Patients treated with thiazides reduced urine calcium in both CaOx (M = -74.4, SD = 94.6 mg/day) and CaP SF (M = -102, SD = 99.7 mg/day), while those on K-Cit had no change in urine calcium. Among CaOx SF, urine citrate rose in patients administered K-Cit with or without thiazide, but citrate did not rise significantly in CaP SF. Urine pH rose in all CaOx SF, but among CaP SF only rose in patients receiving K-Cit. CaOx supersaturation (SS) decreased in all patients who received Thiazide, and decreased among CaOx SF treated with K-Cit. CaP SS decreased in both CaOx SF (M = -0.46, SD = 0.86) and CaP SF (M = -0.76, SD = 0.85) treated with Thiazide except CaOx SF who received Both. Patients treated with K-Cit alone increased CaP SS in CaOx SF (M = 0.25, SD = 0.79). Patients treated with Thiazide lowered urine calcium and SS in both stone groups. Patients treated with K-Cit had no significant changes in urine calcium and had a decrease in CaOx SS in CaOx SF. The study raises questions about the best preventive treatment for patients with CaP stones and suggests that K-Cit may not confer the same benefits on CaP SF as it does on CaOx SF.

Exploring normal urinary biomarker ratios in a pediatric population: insights into age and gender variations

Aims: The assessment of urinary biomarker ratios, such as sodium/creatinine (Na/Crea), potasium/creatinine (K/Crea), calcium/creatinine (Ca/Crea), phosphorus/creatinine (P/Crea), uric acid/creatinine (Uric acid/Crea), magnesium/creatinine (Mg/Crea), and sodium/potassium (Na/K), holds significant importance in clinical and research contexts as they offer insights into physiological and pathological processes. This study aimed to establish the normal ranges of urinarymineral ratios across age and gender groups in a Turkish pediatric cohort. Methods: This cross-sectional study was conducted involving 162 healthy children, with ages ranging from 2 to 15 years, at the Department of Pediatrics, Selçuk University. Demographic information, urinary biomarker ratios, and dietary features were recorded. Participants were divided into three age groups (2-5, 6-10, and 11-15 years), and statistical analyses were performed to determine relationships and variations. Results: Gender distribution was uniform across age groups (p&amp;gt;0.05). Urinary creatinine levels stabilized after age 6. The mean urinary Na/Crea ratio was 0.33±0.22 mEq/mg, showing correlations with age and other ratios (p&amp;lt;0.001). Urinary K/Crea ratio was 0.13±0.15 mEq/mg, with significant differences between Group 1 and Group 3 (p&amp;gt;0.05). Urinary Na/K ratio was 3.5±2.4 mEq/mEq and correlated with uric acid and Ca/Crea ratio (p&amp;lt;0.001). Urinary calcium levels were consistent (p&amp;lt;0.001). Ca/Crea ratio correlated with other ratios (p&amp;lt;0.001). Urine P/Crea ratio differed significantly among groups (p&amp;gt;0.05). Uric acid levels differed between Group 2 and Group 3 (p&amp;gt;0.05), while uric acid//Crea ratio correlated with age and other ratios (p&amp;lt;0.001). Conclusion: The findings provide insights into the normal ranges of urinary biomarker ratios in a Turkish pediatric cohort. The results align with previous studies and emphasize the impact of age, gender, and dietary factors on these ratios.

O-12 A rare cause of parathyroid hormone independent hypercalcemia: 1,25-(OH)2D-24 Hydroxylase (CYP24A1) deficiency

Abstract Background Common causes of parathyroid hormon (PTH)-independent hypercalcemia in adulthood are malignancy, granulomatous diseases, and endocrinopathies. Loss-of-function mutations of CYP24A1 gene, encoding for 1,25-dihydroxyvitamin D3 24-hydroxylase, can also be a rare cause of supressed intact PTH levels, usually associated with, nephrolithiasis and nephrocalcinosis. This disease, defined as idiopathic infantile hypercalcemia, classically presents with hypercalcemia in infants. However, some individuals have also been reported with late-onset clinical manifestation or late diagnosis in adulthood. Clinical Case A 59-year-old male patient with a known diagnosis of type 2 diabetes mellitus for 30 years. He had a history of recurrent kidney stones since 2006. His blood and urine tests revealed elevated creatinine level, hypercalcemia with normal phosphorus levels, normal 25-hydroxycholecalciferol levels, suppressed intact PTH level and normal 24-hour urinary calcium level (Table 1). Urinary ultrasonography was consisted with medullary nephrocalcinosis and chronic kidney disease. PTH-independent causes of hypercalcemia were investigated. Malignancies, granulomatous diseases and endocrinopathies were ruled out. The 1,25-dihydroxycholecalciferol level was within the normal range. Parathormone related peptide level was determined as 1.60 pmol/L (normal value &amp;lt;4.2). Genetic workup revealed a homozygous loss-of-function mutation p.E143del in the CYP24A1 gene. Thereupon, genetic screening started on the siblings of the patient which not been finalized yet. However, none of them were found to have hypercalcemia in the laboratory evaluation. Treatment was started with low-dose fluconazole, which inhibits enzymes (including 25-hydroxylases and 1-α-hydroxylase) synthesizing vitamin D. After a month of treatment at a dose of 50 mg/day, no change was observed in the patient's calcium values. Follow-up with calcium-restricted diet and adequate oral hydration therapy was planned. Conclusion Idiopathic infantile hypercalcemia may manifest later or diagnosed later in adulthood. Genetic examination should be considered in adult patients in whom other causes of PTH-independent hypercalcemia have been excluded.Table 1.Patient's laboratory parameters

P-18 Dent's Disease as a rare cause of rickets

Abstract Introduction Dent's disease is a rare recessive X-linked disorder characterized by hypophosphatemia, hematuria, proteinuria, hypercalciuria, nephrocalcinosis, and progressive renal failure. The majority of cases are caused by mutations in the CLCN5 or OCRL genes. The primary mechanisms of rickets in Dent's disease are a deficiency in phosphate absorption in the proximal tubules of the kidney and an increase in urinary calcium excretion. In order to draw attention to this rare disease, we present a patient diagnosed with Dent's disease while being evaluated for hypophosphatemic rickets. Clinical Case A 23-year-old male patient with Dent's disease was referred to an adult endocrinology clinic for follow-up after a CLCN5 mutation was identified during an examination for hypophosphatemic rickets and proteinuria at the age of three. Since the age of 18, he has been diagnosed with chronic kidney disease. At the age of 19, he has a history of hospitalization for osteomyelitis. No history of fracture. In his family history, both of his parents were cousins, that have short stature and Dent's disease mutation was found to be heterozygous. Both cousins had hypophosphatemic rickets diagnosis. On physical examination, he was mobile, 155 cm tall, weighed 55 kilograms, had bilateral genu valgum, and other system examinations revealed no pathology. The patient was taking 500 mg of phosphate three times per day in addition to 0.5 microgram of calcitriol. In laboratory evaluation, creatinine was 3.11 mg/ dL, GFR was 26 ml/min, PTH was 118 pg/mL, ALP was 82 IU/ml, phosphorus was 3.44 mg/ dL, and calcium was 10 mg/dL. 24-hour urine calcium: 195 mg/day; osteocalcin: 188 ng/mL; beta-crosslaps: 2 ng/mL. It was determined to be high-turnover chronic kidney disease-bone disorder. Urinary ultrasonography showed bilateral kidney diameters decreased and parenchymal thickness thinned, bilateral kidney echoes increased, and bilateral medullary nephrocalcinosis with high echogenicity and calcifications. Cataract and basal ganglia calcification were not detected. Dual Energy X-Ray Absorbsiometry evaluation revealed that the L1-L4 BMD: 0.915 gr/cm2 Z score: -1.1 and the femoral neck BMD: 0.614 gr/cm2 Z score: -3.1 were lower than anticipated for age. The patient's calcitriol dosage was reduced to three times per week after PTH suppression. Since the serum ALP concentration was normal, the oral phosphorus dose was not altered. A limited sodium diet was suggested for the patient. The patient with bilateral nephrocalcinosis was referred to the nephrology clinic for further evaluation. Conclusion Patients diagnosed with rickets should also be mindful of Dent's disease, which must be closely monitored alongside nephrology.Figure 1.Bilateral knee radiograph of the patient

Acidification is required for calcium and magnesium concentration measurements in equine urine

BackgroundAcidification of equine urine to promote dissociation of ion complexes is a common practice for urine ion concentration measurements. The objective of this study was to evaluate the effect of acidification and storage after acidification on calcium (Ca), magnesium (Mg) and phosphate (P) concentrations and on fractional excretion (FE) of these electrolytes. Thirty-two fresh equine urine samples were analysed between December 2016 and July 2020. Complete urinalysis (stick and sediment) was performed on all samples. Ca, Mg, P and creatinine concentrations were measured in supernatant of centrifuged native urine, urine directly centrifuged after acidification and urine centrifuged 1 hour after acidification. Urine was acidified with hydrochloric acid to reach a pH of 1–2. Ca, Mg, P and creatinine concentrations were also measured in blood plasma, and fractional excretion of each electrolyte was calculated. Equality of medians was tested with Friedman tests and Bland-Altman bias plots were used to show the agreement between conditions.ResultsAcidification had a statistically significant effect on Ca and Mg concentrations, FECa and FEMg. Bland-Altman plot revealed a strong positive proportional bias between Ca concentration in native and acidified urine with a mean bias of 17.6 mmol/l. For Mg concentration, the difference between native and acidified urine was small with a mean bias of 1.8 mmol/l. The increase in FECa was clinically relevant. Storage of acidified urine had no effect on any of the measured ion concentrations. All P concentrations in native urine samples were below the detection limit of the assay and statistical analysis and calculation of FEP was not possible.ConclusionsUrine acidification is essential for accurate measurement of Ca and Mg concentrations and therefore FE calculations in equine urine. Storage time of 1 hour after acidification does not significantly change Ca and Mg concentrations.

The Vitamin D Metabolite Diagnostic Ratio Associates With Phenotypic Traits of Idiopathic Hypercalciuria

IntroductionUnderlying mechanisms for hypercalciuria remain unknown in most cases, hence the designation “idiopathic”. We hypothesized that the Vitamin D-inactivating enzyme CYP24A1 contributes to the pathogenesis of hypercalciuria in kidney stone formers. MethodsWe conducted association analyses between CYP24A1 activity, estimated by the Vitamin D metabolite diagnostic ratio (25(OH) Vitamin D3/total 24,25 (OH)2 Vitamin D ratio; VMDR), and the phenotype of participants in two observational cohorts of kidney stone formers, the Swiss Kidney Stone Cohort and the Bern Kidney Stone Registry. Circulating 25(OH)- and 24,25 (OH)2 Vitamin D were quantified using a validated LC-MS/MS assay. Results974 participants were included in the analysis. We found a positive association of VMDR (and hence negative association of CYP24A1 activity) with total (β 0.009 mmol/L; 95% CI 0.002, 0.016; p = 0.02) and ionized plasma calcium (β 0.005 mmol/L; 95% CI 0.002, 0.008; p < 0.01), absolute and fractional excretion of urinary calcium (β 0.054 mmol/24h; 95% CI 0.010, 0.097; p = 0.02 and β 0.046 %; 95% CI 0.018, 0.074; p < 0.01, respectively). Further, VMDR was associated with an increased likelihood of forming calcium oxalate dihydrate stones (Odds ratio 1.64; 95% CI 1.22, 2.35; p < 0.01) and reduced bone mineral density at the femoral neck (β -0.005 g/cm2; 95% CI -0.010, -0.001; p = 0.04). The described associations became stronger when the analysis was confined to idiopathic calcium stone formers. ConclusionOur study reveals that CYP24A1 activity, estimated by VMDR, is associated with clinical traits previously linked to idiopathic hypercalciuria.

Correlation of Calcium Metabolic Axis with Urinary Stone Characteristics

Background: Urinary stone disease (USD) refers to the presence of stones or salt crystals within the urinary tract, with calcium stones accounting for approximately 80% of cases. Increased urinary calcium and phosphorus excretion predispose individuals to urinary stones, with hypercalciuria being the most significant risk factor. Vitamin D plays a pivotal role in modifying urine calcium and phosphorus excretion, and it enhances calcium and phosphorus reabsorption in the kidneys. Urinary stone disease is a recognized risk factor for chronic kidney disease (CKD) and may also lead to life-threatening complications such as perinephric abscesses, urosepsis, and urinary tract malignancies. The role of serum vitamin D and its effects on serum calcium and phosphorus in urinary stone formation have been subjects of controversy. Objectives: This study aims to evaluate the associations between serum calcium, phosphorus, and vitamin D levels and urinary stones. Methods: This retrospective study involved two groups of 90 patients, one with urinary stones and the other without. Demographic and biochemical data, including serum calcium, phosphorus, and 25-(OH) vitamin D levels, were recorded for all patients. Patients were categorized into four groups based on their serum vitamin D levels: Excess, sufficient, insufficient, and deficient. The presence and characteristics of urinary stones were assessed using non-contrast CT scans. Results: The mean age of the patients was 54.62 ± 15.46 years. Laboratory investigations revealed mean serum calcium, phosphorus, and vitamin D levels of 9.56 ± 0.65 mg/dL, 3.53 ± 0.79 mg/dL, and 25.05 ± 12.96 ng/mL, respectively. This study demonstrated a significant correlation between serum calcium levels and the maximum diameter of urinary stones (correlation = 0.313, P-value = 0.005). No other significant associations were found between serum calcium, serum phosphorus, and serum vitamin D levels and the number of kidney stones, stone laterality, and type of kidney stone. There was also no significant difference between the two groups. Conclusions: In conclusion, the role of serum calcium, phosphorus, and 25-(OH) vitamin D levels in urinary stone formation remains controversial. This study suggests that there is no significant association between serum calcium, phosphorus, or 25-(OH) vitamin D and urinary stones, except for a positive association between serum calcium and the diameter of the stone.

Effects of Klotho protein, vitamin D, and oxidative stress parameters on urinary stone formation and recurrence.

The present study aimed to investigate the effects of α-Klotho and oxidative stress markers on urinary stone disease (USD) and demonstrate their use as biochemical markers in USD. Among the 90 individuals included, 30 individuals were healthy controls (Group 1), 30 individuals presented with USD for the first time (Group 2), and 30 individuals demonstrated recurrent USD (Group 3). Serum levels of α-Klotho, vitamin D, malondialdehyde (MDA), total oxidant status, and total antioxidant status were determined using spectrophotometry analysis. Serum calcium and parathormone levels and 24-h urine calcium levels were measured via biochemical analysis. No significant intergroup difference was noted in terms of age and sex. The groups had significant differences regarding α-Klotho, oxidative stress index (OSI), MDA, and 24-h urine calcium levels. α-Klotho was a determinant of 24-h urine calcium level and OSI. An increase of 1pg/mL in α-Klotho level appeared to result in a decrease of 8.55mg in 24-h urine calcium level and a decrease of 0.04 Arbitrary Unit in OSI. In patients experiencing USD for the first time, α-Klotho values were < 21.83pg/mL and showed 66% sensitivity and 64% specificity. In individuals with recurrent stone formation, α-Klotho values below 19.41pg/mL had 60% sensitivity and 77% specificity. The biochemical markers investigated herein, i.e., α-Klotho, OSI, and MDA, were involved in the pathogenesis of stone formation and can be used in day-to-day clinical practices of urology clinics to identify patients at risk for both first time and recurrent USD.

A prospective case-control study on the evaluation of oxidative stress in renal stone formers.

Association of increased oxidative stress (OS) with the pathophysiology of renal stone formation has not been explored greatly in the field of urolithiasis. In this prospective case-control study, we measured 24-h urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in patients with urolithiasis and compared them with matched healthy controls. We also measured 24-h urinary uric acid, calcium, oxalate, and citrate levels in patients with renal stone disease and studied their relation with urinary 8-OHdG levels. Seventy-five cases of renal stone disease and 75 well-matched controls were included. Median 24-h urinary 8-OHdG levels were significantly higher in cases compared to controls (7.6 vs. 3.7µg/g of creatinine; p < 0.000). Receiver-operating curve (ROC) analysis for 8-OHdG between cases and controls revealed an area under the curve of 0.90. At 8-OHdG (µg/g of creatinine) value of 5 or more, a sensitivity and a specificity of 84% each were obtained. A positive correlation between 8-OHdG (µg/g of creatinine) and 24-h urinary oxalate level was noted (r = 0.461, p = 0.000). No correlation between 8-OHdG (µg/g of creatinine) and other variables was noted. On multivariate linear regression analysis, we noted 24-h urinary oxalate levels to be an independent predictor of urinary 8-OHdG levels. OS is significantly higher in patients with renal stone diseases compared to healthy controls. Urinary oxalate levels were significantly correlated with urinary 8-OHdG levels.

Caffeine and Ovariectomy Debilitate Bone Health in Rats on Calcium-deficient Diet.

This study investigated the effects of ovariectomy and caffeine intake on bone health in rats on calcium-deficient diet. Forty adults female Wistar rats were divided into 4 groups in a 2x2 factorial design: Ovary (OVX/SHAM) and Caffeine (placebo/caffeine). The animals were housed in individual cages for 8 weeks, receiving 18-20g of AIN-93M diet per day, containing 50% of the daily recommended intake of calcium. The rats underwent ovariectomy (OVX) or laparotomy (SHAM) surgery. Caffeine groups received 6mg of caffeine/kg/day. After euthanasia, the tibia and femur were dissected to determine the calcium content and bone fracture strength, respectively. Blood sample was collected to determine serum Ostase. 24-hour urine was analyzed for excreted calcium and NTx. Reduced bone fracture strength and calcium content were observed in OVX and Caffeine groups. When observed separately, OVX group showed increased urinary NTx and lower bone weight, blood ostase, and urinary calcium. Caffeine groups showed elevated urinary calcium. There was a positive correlation between bone fracture strength and calcium content. NTx correlated negatively with bone calcium, fracture strength and thickness. In conclusion, both OVX and caffeine intake debilitate bone health in rats on calcium-deficient diet.

Molecular docking and in vivo protective effects of okra (Abelmoschus esculentus) against metabolic dysfunction in high-fat, high-sodium diet-fed rats.

Okra pods (Abelmoschus esculentus L. Moench) have been used as a functional vegetable as they contain polysaccharides, flavonoids, and other bioactive molecules that protect the body from several chronic diseases. The purpose of this study was to look at the involvement of okra constituents (mucilage and flesh) in the prevention of metabolic dysfunctions induced in a rat model by a high-fat, high-salt (HF/NaCl) diet. Okra mucilage was extracted using an ultrasonic method, freeze-dried, characterized using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM), and tested for swelling ratio and radical scavenging activity. Okra flesh (skin and seeds) was separated from pods; characterized using SEM; and tested for dietary fiber content, phenolic profile, and radical scavenging activity. The significance of okra bioactive compounds in inhibiting human salivary amylase, glutamine : fructose-6-phosphate amidotransferase (GFAT), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP) was investigated using molecular docking. Rats were fed an HF/NaCl diet and orally treated daily with freeze-dried okra mucilage or flesh (100 mg per kg body weight) for 8 weeks. Glucose, insulin, inflammatory indicators (CRP, TNF-α, and interleukin 6), oxidative markers (red blood cell lipid peroxidation, glutathione peroxidase, nitric oxide, and superoxide dismutase), lipid profile, estradiol, feces lipids as well as femur and urine calcium were measured. The molecular docking findings showed the interaction of quercetin and chlorogenic acid, which are the most abundant phenolic compounds in okra pods, with the studied proteins, which gives an indication of the mechanism of okra's anti-diabetic, anti-oxidant, and anti-inflammatory effects. Okra mucilage and flesh significantly reduced glucose, insulin, cholesterol, lipid peroxidation, CRP, TNF-α, IL-6, and urine calcium levels while significantly increasing feces lipid and femur calcium levels. The findings suggested that okra mucilage and flesh seem to be promising candidates for protection against metabolic dysfunction.