Simultaneous determination of 24,25- and 25,26-dihydroxyvitamin D3 in serum samples with liquid-chromatography mass spectrometry - A useful tool for the assessment of vitamin D metabolism.

Vitamin D status is typically assessed by the measurement of 25-hydroxyvitamin D (25(OH)D). However, in selected patient groups the sole determination of 25(OH)D has been proven insufficient for this purpose. The simultaneous measurement of additional vitamin D metabolites may provide useful information for a better evaluation of the vitamin D status. Therefore, we developed and validated a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of 25(OH)D3, 25(OH)D2, 24,25(OH)2D3 and additionally 25,26(OH)2D3, which was identified with a synthesized pure substance. Pure and deuterated substances were used to prepare calibrators and internal standards for all target metabolites. Pre-analytical sample preparation comprised protein precipitation followed by liquid-liquid-extraction and derivatization with 4-Phenyl-1,2,4-triazole-3,5-dione (PTAD) using 50 µL sample volume. Samples were analyzed on an Agilent HPLC 1260 system equipped with a silica-based Kinetex® 5 µm F5 100 Å core-shell column (150 × 4.6 mm) coupled to a Sciex 4500 mass spectrometer. For all four metabolites, limit of detection (LoD) and limit of quantification (LoQ) ranged from 0.3 to 1.5 nmol/L and 1.0 to 3.1 nmol/L, respectively. Recovery varied between 76.1 % and 84.3 %. Intra- and inter-assay imprecision were <8.6 % and <11.5 %, respectively. The analysis of external and internal quality control samples showed good accuracy for 25(OH)D3, 25(OH)D2, 24(R),25(OH)2D3 and 25,26(OH)2D3. Method comparison studies with human samples that were also analyzed with two other LC-MS/MS methods showed close agreement. Finally, the present method has been shown capable of identifying patients with 24-hydroxylase deficiency, which proves its clinical utility.

Post-treatment levels of plasma 25- and 1,25-dihydroxy vitamin D and mortality in men with aggressive prostate cancer.

Vitamin D may reduce mortality from prostate cancer (PC). We examined the associations of post-treatment plasma 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D concentrations with PC mortality. Participants were PC cases from the New South Wales Prostate Cancer Care. All contactable and consenting participants, at 4.9 to 8.6 years after diagnosis, were interviewed and had plasma 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D) measured in blood specimens. Cox regression allowing for left-truncation was used to calculate adjusted mortality hazards ratios (HR) and 95% confidence intervals (95% CI) for all-cause and PC-specific mortality in relation to vitamin D levels and other potentially-predictive variables. Of the participants (n = 111; 75·9% response rate), there were 198 deaths from any cause and 41 from PC in the study period. Plasma 25(OH)D was not associated with all-cause or PC-specific mortality (p-values > 0·10). Plasma 1,25(OH)2D was inversely associated with all-cause mortality (HR for highest relative to lowest quartile = 0·45; 95% CI: 0·29-0·69), and PC-specific mortality (HR = 0·40; 95% CI: 0·14-1·19). These associations were apparent only in men with aggressive PC: all-cause mortality HR = 0·28 (95% CI·0·15-0·52; p-interaction = 0·07) and PC-specific mortality HR = 0·26 (95% CI: 0·07-1.00). Time spent outdoors was also associated with lower all-cause (HR for 4th relative to 1st exposure quartile = 0·42; 95% CI: 0·24-0·75) and PC-specific (HR = 0·48; 95% CI: 0·14-1·64) mortality, although the 95% CI for the latter was wide. The inverse association between post-treatment plasma 1,25(OH)2D levels and all-cause and PC-specific mortality in men with aggressive PC, suggest a possible beneficial effect of vitamin D supplementation in these men.

Vitamin D release across abdominal adipose tissue in lean and obese men: The effect of ß-adrenergic stimulation.

Obesity is characterized by a blunted lipolytic response in abdominal subcutaneous adipose tissue (SAT) and low circulating vitamin D levels. Here we investigated whether an impaired SAT lipolytic response coincides with an impaired SAT vitamin D release in eight lean and six obese men. 25-hydroxyvitamin D3 [25(OH)D3 ] and 1,25-dihydroxyvitamin D3 [1,25(OH)2 D3 ] fluxes across SAT were measured using arterio-venous blood sampling in combination with AT blood flow measurements after an overnight fast and during 1-hr intravenous infusion of the non-selective ß-adrenergic agonist isoprenaline (20 ng·kg FFM-1 ·min-1 ). 1,25(OH)2 D3 was released across abdominal SAT during isoprenaline infusion in lean [-0.01 (-0.04 to 0.00) pmol*100 g tissue-1 *min-1 , p = .017 vs. zero flux], but not in obese men [0.01 (0.00 to 0.02) pmol*100 g tissue-1 *min-1 , p = .116 vs. zero flux], and accompanied by an impaired isoprenaline-induced lipolytic response in abdominal SAT of obese versus lean men. Isoprenaline had no significant effects on net 25(OH)D3 release across abdominal SAT and plasma vitamin D metabolites in lean and obese men. To conclude, a blunted isoprenaline-mediated lipolysis is accompanied by reduced release of 1,25(OH)2 D3 vitamin D across abdominal SAT in obesity.

5α-dihydrotestosterone reduces renal Cyp24a1 expression via suppression of progesterone receptor.

Androgens act in concert with vitamin D to influence reabsorption of calcium. However, it is unclear whether androgens directly regulate vitamin D homeostasis or control other cellular events that are related to vitamin D metabolism. To examine whether the expression of vitamin D-related genes in mouse kidney is driven by androgens or androgen-dependent effects, the androgen receptor and other sex steroid receptors were monitored in orchidectomized mice treated with 5α-dihydrotestosterone (DHT). Our results revealed that exposing orchidectomized mice to DHT inhibited the expression of progesterone receptor (Pgr) with or without estrogen receptor α expression, the latter was confirmed by ER-positive (MCF7 and T47D) or -negative (PCT) cells analysis. The loss of Pgr in turn decreased the expression of renal 24-hydroxylase via transcriptional regulation because Cyp24a1 gene has a progesterone receptor-binding site on promoter. When male kidneys preferentially hydroxylate 25-hydroxyvitamin D3 using 24-hydroxylase rather than 25-hydroxyvitamin D3-1-alpha hydroxylase, DHT suppressed the Pgr-mediated 24-hydroxylase expression, and it is important to note that DHT increased the blood 25-hydroxyvitamin D3 levels. These findings uncover an important link between androgens and vitamin D homeostasis and suggest that therapeutic modulation of Pgr may be used to treat vitamin D deficiency and related disorders.

Parathyroid Hormone Levels in the Prediction of Ischemic Stroke Risk.

Objective. It was examined whether PTH and 25-dihydroxyvitamin D (25(OH)D) levels, together or separately, are indicators of the risk of stroke. Materials and Methods. This prospective study was performed at two centers. In the study, 100 patients diagnosed with acute ischemic stroke and 100 control individuals in the same age range were examined. In addition to neurological examination, cranial imaging, extensive routine blood chemistry, PTH, and 25(OH)D levels were evaluated in all cases. Stroke risk factors were determined. Logistic regression was used for statistical analysis. Results. A total of 60 patients and 79 control individuals were included in the study. Different estimation models were designed in order to examine the relationship between PTH and 25(OH)D levels with stroke. According to modeling results, it was determined that the most effective predictor for risk of stroke was 25(OH)D levels, followed by hypertension and PTH levels, respectively. Conclusion. PTH and 25(OH)D levels together can make important contributions to determination of stroke risk, and further investigations are needed to understand this relationship more fully.

Vitamin D Deficiency and Metabolism in HIV-Infected and HIV-Uninfected Men in the Multicenter AIDS Cohort Study.

We evaluated associations of serum 25-hydroxyvitamin D (25[OH]D) and 1,25-dihydroxyvitamin D (1,25[OH]2D) levels in a cohort of HIV-infected and HIV-uninfected men at risk for infection in the United States. Stored samples collected between 1999 and 2008 were tested for vitamin D metabolites between 2014 and 2015. Vitamin D deficiency was defined as a serum concentration of 25[OH]D <20 ng/ml. Multivariate models were used to assess associations of various demographic and clinical factors with vitamin D status. HIV-infected men on effective antiretroviral therapy (n = 640) and HIV-uninfected men (n = 99) had comparable levels of 25[OH]D and 1,25[OH]2D, and prevalences of vitamin D deficiency were 41% in HIV-infected and 44% in HIV-uninfected men, respectively. Self-reported black or other non-white race, obesity, and normal kidney function were significant predictors of vitamin D deficiency regardless of HIV serostatus. Lower CD4+ T cell count was associated with vitamin D deficiency in HIV-infected men, while current ritonavir use was protective. Self-reported black race was the only factor significantly associated with higher levels of 1,25[OH]2D (vs. whites; ß = 4.85 pg/ml, p = .003). Levels of 1,25[OH]2D and 25[OH]D were positively correlated in HIV-infected men (ß = 0.32 pg/ml, p < .001), but not in uninfected men (ß = -0.09 pg/ml, p = .623; p < .05 for interaction). Vitamin D deficiency was prevalent regardless of HIV serostatus in this cohort, suggesting that HIV infection did not confer additional risk of deficiency in this cohort of well-treated HIV-infected men. However, HIV infection and race may have implications for vitamin D metabolism and 1,25[OH]2D levels.

Efficacy of High-Dose Vitamin D Supplements for Elite Athletes.

PURPOSE: Supplementation with dietary forms of vitamin D is commonplace in clinical medicine, elite athletic cohorts, and the general population, yet the response of all major vitamin D metabolites to high doses of vitamin D is poorly characterized. We aimed to identify the responses of all major vitamin D metabolites to moderate- and high-dose supplemental vitamin D3. METHODS: A repeated-measures design was implemented in which 46 elite professional European athletes were block randomized based on their basal 25[OH]D concentration into two treatment groups. Athletes received either 35,000 or 70,000 IU·wk vitamin D3 for 12 wk, and 42 athletes completed the trial. Blood samples were collected for 18 wk to monitor the response to supplementation and withdrawal from supplementation. RESULTS: Both doses led to significant increases in serum 25[OH]D, and 1,25[OH]2D3. 70,000 IU·wk also resulted in a significant increase of the metabolite 24,25[OH]2D at weeks 6 and 12 that persisted after supplementation withdrawal at week 18, despite a marked decrease in 1,25[OH]2D3. Intact parathyroid hormone was decreased in both groups by week 6 and remained suppressed throughout the trial. CONCLUSIONS: High-dose vitamin D3 supplementation (70,000 IU·wk) may be detrimental for its intended purposes because of increased 24,25[OH]2D production. Rapid withdrawal from high-dose supplementation may inhibit the bioactivity of 1,25[OH]2D3 as a consequence of sustained increases in 24,25[OH]2D that persist as 25[OH]D and 1,25[OH]2D concentrations decrease. These data imply that lower doses of vitamin D3 ingested frequently may be most appropriate and gradual withdrawal from supplementation as opposed to rapid withdrawal may be favorable.

1,25(OH)2D3 dependent overt hyperactivity phenotype in klotho-hypomorphic mice.

Klotho, a protein mainly expressed in kidney and cerebral choroid plexus, is a powerful regulator of 1,25(OH)2D3 formation. Klotho-deficient mice (kl/kl) suffer from excessive plasma 1,25(OH)2D3-, Ca(2+)- and phosphate-concentrations, leading to severe soft tissue calcification and accelerated aging. NH4Cl treatment prevents tissue calcification and premature ageing without affecting 1,25(OH)2D3-formation. The present study explored the impact of excessive 1,25(OH)2D3 formation in NH4Cl-treated kl/kl-mice on behavior. To this end kl/kl-mice and wild-type mice were treated with NH4Cl and either control diet or vitamin D deficient diet (LVD). As a result, plasma 1,25(OH)2D3-, Ca(2+)- and phosphate-concentrations were significantly higher in untreated and in NH4Cl-treated kl/kl-mice than in wild-type mice, a difference abrogated by LVD. In each, open field, dark-light box, and O-maze NH4Cl-treated kl/kl-mice showed significantly higher exploratory behavior than untreated wild-type mice, a difference abrogated by LVD. The time of floating in the forced swimming test was significantly shorter in NH4Cl treated kl/kl-mice compared to untreated wild-type mice and to kl/kl-mice on LVD. In wild-type animals, NH4Cl treatment did not significantly alter 1,25(OH)2D3, calcium and phosphate concentrations or exploratory behavior. In conclusion, the excessive 1,25(OH)2D3 formation in klotho-hypomorphic mice has a profound effect on murine behavior.

[Vitamin D and neuropsychological assessment of cognitive functions: a study of their relationships in a sample of 244 patients attending a memory clinic]. / Vitamine D et évaluation neuropsychologique des fonctions cognitives : étude chez 244 sujets âgés pris en charge en hôpital de jour mémoire.

There is evidence of a role of vitamin D in cognitive functioning, but little is known about the type of functions involved. To describe vitamin D status in a population of old patients with memory complaints and its relationships with cognitive performance and white matter lesions. A retrospective single-centre observational study from the medical records of 244 patients who had a measurement of serum 25OHD together with a battery of neuropsychological tests during a complete geriatric and memory assessment in a day care hospital. The results of the 10 neuropsychological tests considered in this study were analysed as binary variables, opposing patients with results within the highest two tertiles to patients with the worse results or unable to perform the test. Mean age of people included was 80.2 ± 8.1 years and 64% of patients were women. Severe deficiency in vitamin D (25OHD <10 ng/mL) was found in 34 patients (13.9%) and moderate deficiency (10 ≤ 25OHD < 30 ng/mL) in 148 (60.7%). Compared to subjects with sufficient concentrations in vitamin D, patients with severe deficiency performed significantly worse on a global test, the Mini mental state examination, and two tests of verbal memory, the 5 words and the 16-item free and cued recall, independently from age, gender, education, body mass index and autonomy (OR = 2.85 [1.04-7.85], 4.31 [1.42-13.07], and 3.04 [1.01-9.19] respectively). Levels of vitamin D did not differ according to the extent of white matter lesions, visualized semi-quantitatively on magnetic resonance imaging of 115 subjects. This study confirms the high prevalence of vitamin D deficiency in elderly population and suggests a link between vitamin D deficiency and memory.

Calcium and bone homeostasis in heterozygous carriers of CYP24A1 mutations: A cross-sectional study.

BACKGROUND: Bi-allelic CYP24A1 mutations can cause idiopathic infantile hypercalcemia (IIH), adult-onset nephrocalcinosis, and possibly bone metabolism disturbances. It is currently unclear if heterozygous carriers experience clinical problems or biochemical abnormalities. Our objective is to gain insight in the biochemical profile and health problems in CYP24A1 heterozygotes. STUDY DESIGN: Cross-sectional evaluation of participants. Data of previously reported carriers are reviewed. SETTING AND PARTICIPANTS: Outpatient clinic of a tertiary care hospital. Participants were eight family members of an infant with a well-characterized homozygous CYP24A1 mutation c.1186C>T p.(Arg396Trp). OUTCOMES: Serum vitamin D metabolites. Symptoms or biochemical signs of hypercalcemia, hypercalciuria or nephrocalcinosis. Bone health in heterozygous as compared to wild type (WT) subjects. MEASUREMENTS: Genotyping by Sanger sequencing; vitamin D metabolites by liquid chromatography tandem mass spectrometry; renal, calcium and bone markers by biochemical analyses; presence of nephrocalcinosis by renal ultrasound; bone health by dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. RESULTS: Six participants were heterozygous carriers of the mutation. None of the heterozygous subjects had experienced IIH. One had a documented history of nephrolithiasis, two others had complaints compatible with this diagnosis. No major differences between WT and heterozygous subjects were found regarding bone health, serum or urinary calcium or 25OHD/24,25(OH)2D ratio. Literature reports on three out of 33 heterozygous cases suffering from IIH. In all three, the 25OHD/24,25(OH)2D ratio was highly elevated. Nephrocalcinosis was frequently reported in family members of IIH cases. LIMITATIONS: Small sample size, lack of a large control group. CONCLUSIONS: Our and literature data suggest that most heterozygous CYP24A1 mutation carriers have a normal 25OHD/24,25(OH)2D ratio, are usually asymptomatic and have a normal skeletal status but may possibly be at increased risk of nephrocalcinosis. A review of the available literature suggests that an elevated 25OHD/24,25(OH)2D ratio may be associated with symptoms of IHH, irrespective of carrier status.

Enhanced induction of Cyp24a1 by FGF23 but low serum 24,25-dihydroxyvitamin D in CKD: implications for therapy.

In normal people, induction by FGF23 of renal Cyp24a1, the enzyme that degrades 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, helps to protect from the disorders caused by excessive 1,25-dihydroxyvitamin D. Dai and co-workers report, however, that in human and mouse kidney disease, high FGF23 concurs with low rather than high serum 24,25-dihydroxyvitamin D, a biomarker of Cyp24a1 activity. Their characterization of the underlying mechanisms provides new understanding of how kidney disease impairs the health benefits of vitamin D-FGF23/klotho interactions.

Assessment of 24,25(OH)2D levels does not support FGF23-mediated catabolism of vitamin D metabolites.

Progressive elevations of fibroblastic growth factor 23 (FGF23) in chronic kidney disease may reduce serum 25-hydroxyvitamin D (25(OH)) and 1,25-dihydroxyvitamin D (1,25(OH)(2)D) levels, via stimulation of 24-hydroxylase (Cyp24a1)-mediated catabolism of these vitamin D metabolites. To test this possibility, we measured serum concentrations of 24,25-dihydroxyvitamin D (24,25(OH)(2)D), a product of Cyp24a1 hydroxylation of 25(OH)D, in the Col4a3 knockout mouse, a model of Alport syndrome-derived chronic kidney disease, and in patients with chronic kidney disease of variable severity. There was an inverse correlation between serum FGF23 and both 25(OH)D and 1,25(OH)(2)D in the mouse model, but no significant relationship was observed in the cross-sectional patient cohort. The FGF23-dependent increase in Cyp24a1 mRNA expression in the mouse kidneys was consistent with the possibility that FGF23 induces vitamin D catabolism. There was, however, a reduction in serum 24,25(OH)(2)D levels, rather than the expected elevation, in both the mice and patients with chronic kidney disease. Low 25(OH)D and elevated FGF23 and parathyroid hormone levels were correlated with the reduced serum 24,25(OH)(2)D concentrations of these patients. Thus, we failed to find support for FGF23-mediated catabolism of vitamin D metabolites in chronic kidney disease assessed by 24,25(OH)(2)D levels.

Vitamin D status, adiposity, and lipids in black American and Caucasian children.

OBJECTIVE: The aim of the study was to examine the relationship between vitamin D status, total and abdominal adiposity, and lipids in black and white children. METHODS: Plasma 25-hydroxyvitamin D [25(OH)D], adiposity [body mass index (BMI), percentage of total body fat, visceral adipose tissue (VAT), sc adipose tissue (SAT)], and fasting lipids were assessed in healthy obese and nonobese 8- to 18-yr-old black and white children. RESULTS: We studied 237 children (mean ± sd age, 12.7 ± 2.2 yr; 47% black, 47% obese, and 43% male). Mean 25(OH)D concentration for the entire cohort was 19.4 ± 7.4 ng/ml. The majority of the children were vitamin D deficient [25(OH)D < 20 ng/ml; 73% blacks, 40% whites]. Plasma 25(OH)D was associated inversely with BMI, BMI percentile, percentage of total body fat, VAT, and SAT and positively with HDL cholesterol in the entire cohort. VAT was higher in vitamin D-deficient whites, and SAT was higher in vitamin D-deficient blacks compared with their respective vitamin D-nondeficient counterparts. Race, season, pubertal status, and VAT were independent significant predictors of 25(OH)D status. CONCLUSIONS: In black and white youth examined together, lower levels of 25(OH)D are associated with higher adiposity measures and lower HDL. Furthermore, vitamin D deficiency is associated with higher VAT in whites and greater SAT in blacks. Besides therapeutic interventions to correct the high rates of vitamin D deficiency in youth, benefits of vitamin D optimization on adiposity measures and lipid profile need to be explored.

Vitamin D and hyperparathyroidism in obesity.

BACKGROUND: Low vitamin D status and hyperparathyroidism occur in obesity and may be involved in pathogenesis of obesity-associated comorbid conditions. AIMS: Our aims were to determine in obesity whether there was vitamin D insufficiency, assessed by serum 25-hydroxyvitamin D (s25D) and serum PTH (sPTH) and whether it related to comorbid conditions. METHODS: We conducted a case-control study of 48 women having bariatric surgery and 50 healthy women frequency matched for race, age, year, and season of study. Height, weight, s25D, sPTH, serum 1,25-dihydroxyvitamin D (s1,25D), serum bone alkaline phosphatase, serum cross-linked N-telopeptides of type 1 collagen, and serum calcium, phosphate, creatinine, glucose, and insulin were measured, and comorbid conditions were documented from patient files. RESULTS: Weight (140 vs. 76 kg, P < 0.001), sPTH (44.4 vs. 25.6 pg/ml, P < 0.001), s1,25D (39 vs. 24 pg/ml, P < 0.001), serum bone alkaline phosphatase (19 vs. 12 ng/ml, P < 0.001), serum cross-linked N-telopeptides of type 1 collagen (9.6 vs. 7.9 nm bone collagen equivalents, P = 0.007), serum phosphate (3.45 vs. 3.24 mg/dl, P = 0.043), and serum creatinine (1.05 vs. 0.87 mg/dl, P < 0.001) were higher, and s25D (16 vs. 23 ng/ml, P <.001) was lower in bariatric-surgery women than control women. s25D was lower in bariatric-surgery women than controls in summer (17 vs. 26 ng/ml, P < 0.0001) but not winter (15 vs. 18 ng/ml, P > 0.2). Multiple regression analysis demonstrated that weight predicted s25D (P < 0.001) and sPTH (P = 0.001), but s25D did not predict sPTH or the presence of comorbid conditions except for osteoarthritis. CONCLUSION: Women having bariatric surgery had lower s25D and higher sPTH. The major determinant of s25D and sPTH was weight. Hyperparathyroidism in obesity did not indicate vitamin D insufficiency. Low s25D was not associated with comorbid conditions, apart from osteoarthritis.

Vitamin D deficiency is associated with depletion of circulating endothelial progenitor cells and endothelial dysfunction in patients with type 2 diabetes.

CONTEXT: Vitamin D (Vit-D) deficiency is associated with type 2 diabetes mellitus (DM) and endothelial dysfunction. The relationship of Vit-D deficiency with circulating endothelial progenitor cells and endothelial dysfunction in type 2 DM patients nonetheless remains unclear. OBJECTIVE: We aimed to investigate the cross-sectional association of Vit-D status with brachial flow-mediated dilation (FMD) and circulating endothelial progenitor cell (EPC) numbers in type 2 DM patients. DESIGN, SETTING, AND PARTICIPANTS: We conducted a cross-sectional study of 280 patients (59% male, aged 68 ± 10 yr) with type 2 DM recruited in outpatient clinics during the winter period. MAIN OUTCOME MEASURE: We measured serum 25-hydroxyvitamin D [25(OH)D] by an ELISA kit, circulating CD34+/kinase insert domain-containing receptor (KDR)+ and CD133+/KDR+ EPCs by flow cytometry and brachial artery FMD by vascular ultrasound, respectively. RESULTS: The mean serum 25(OH)D concentration was 25.00 ± 9.17 ng/ml, and 34.3% of patients had Vit-D deficiency [25(OH)D < 20 ng/ml]. Serum 25(OH)D concentration had a significant correlation with hemoglobin A1c level [B = -0.018, 95% confidence interval (CI) -0.035 to -0.002, P = 0.032]. Patients with Vit-D deficiency status had significantly lower brachial FMD (mean difference -1.43%, 95% CI -2.31 to -0.55, P = 0.001) and CD133+/KDR+EPC counts (mean difference -0.12%, 95% CI -0.21 to -0.019, P = 0.022) than those with sufficient Vit-D status after adjustment for age, sex, and cardiovascular risk factors, including hemoglobin A1c levels. CONCLUSIONS: Our results demonstrate that serum 25(OH)D status was significantly associated with brachial artery FMD and circulating CD133+/KDR+EPCs. This suggests that Vit-D deficiency might contribute to depletion of EPCs and endothelial dysfunction in patients with type 2 DM.

[Phosphorus and calcium metabolism and the cardiovascular system status in patients with early-stage chronic renal disease].

AIM: To define the impact of phosphorus and calcium metabolic disturbances in patients with early-stage chronic renal disease (CRD) on the cardiovascular system. SUBJECTS AND METHODS: The levels of phosphate (P), calcium, parathyroid hormone (PTH), 25(OH) vitamin D and 1,25(OH)2 vitamin D, serum lipidogram, carotid artery intima-media thickness (IMT), and X-ray degree of abdominal artery calcification (AAC) were determined and echocardiography, electrocardiography and blood pressure monitoring were made in 465 patients with Stages I-V CRD who did not receive renal replacement therapy (of them, 73.5% of the patients had early (I to III) stages). RESULTS: Blood 1,25(OH)2D was related inversely to left ventricular (LV) posterior wall thickness, blood pressure (BP), triglycerides, and the degree of AAC and correlated directly to the severity of LV diastolic dysfunction and inversely to IMT, the presence of coronary heart disease and heart failure (HF). ACC, LV hypertrophy, and arterial hypertension (AH) were more significant in patients with higher serum levels PTH and P. CONCLUSION: In patients with early-stage CRD, phosphorus and calcium metabolic disturbances promote the development of AH, vascular and cardiac valvular calcification, myocardial hypertrophy, and HF.

Elevated 1, 25-dihydroxyvitamin D levels are associated with protracted treatment in sarcoidosis.

BACKGROUND: Active vitamin D metabolite, 1, 25-dihydroxyvitamin D, has pleomorphic effects on both innate and acquired immunity. Sarcoid granuloma derived 1, 25-dihydroxyvitamin D leads to hypercalcemia, but the association of 1, 25-dihydroxyvitamin D with the clinical phenotype of the disease is currently unknown. OBJECTIVE: To determine the relationship between serum 1, 25-dihydroxyvitamin D levels and the degree of sarcoidosis disease chronicity. DESIGN: Serum 1, 25-dihydroxyvitamin D levels were measured and associated with sarcoidosis activity and phenotypes as assessed by Sarcoidosis Severity Score and Sarcoidosis Clinical Activity Classification respectively. RESULTS: Fifty nine patients were recruited with 44% having a sub-acute onset, and the chronic disease phenotype. There was no significant difference in serum 1, 25-dihydroxyvitamin D levels by chest radiograph stage (p = 0.092) nor did the levels correlate with the Sarcoidosis Severity Score (r = -0.16; p = 0.216). Serum 1, 25-dihydroxyvitamin D levels were associated with patients requiring repeated regimens of systemic immunosuppressive therapy or >1 year of therapy (SCAC Class 6). Increasing quartiles of serum 1, 25-dihydroxyvitamin D level was associated increased odds of the chronic phenotype (OR 1.82, 95% CI, 1.11, 2.99, p = 0.019). The majority (71%) of the patients with levels >51 pg/mL required chronic immunosuppressive therapy as defined by SCAC class 6. CONCLUSIONS: In patients with sarcoidosis, elevated 1, 25-dihydroxyvitamin D levels are associated with chronic treatment needs.

Vitamin D metabolite-mediated hypercalcemia with suppressed parathormone concentration in Pneumocystis jiroveci pneumonia after kidney transplantation.

Pneumocystis jiroveci pneumonia (PJP) is a severe complication in immunocompromised hosts including transplant recipients. Hypercalcemia (HCa) is not a classic symptom of the disease. However, HCa (mean [SD; range], 2.90 [0.20; 2.71-3.17] mmol/L) was detected in 5 patients with PJP at diagnosis. The HCa was associated with decreased concentrations of circulating parathormone (PTH), from 294 (292) ng/L 3 to 6 months previously to 20 (23.5; 7-53) ng/L. Concentrations of 1,25-(OH)2 vitamin D, measured in 3 patients, were in the high normal range (54.66 [7.23; 225-66] microg/L), whereas 25-(OH) vitamin D concentrations were low (13.9 [2.17; 20-60] microg/L). After treatment with trimethoprim-sulfamethoxazole for 21 days, 4 patients recovered and 1 died. Calcium and PTH concentrations rapidly returned to normal (2.36 [0.05] mmol/L and 89 [29.7] ng/L, respectively) at 2 months after the acute phase of the disease. Although fewer than 10 cases of PJP-associated HCa have been reported to date, it is possible that this association is more frequent than previously thought because our cases were detected during 2 years. As in other granulomatous disease-induced HCa, including fungal infections, it is likely that endogenous extrarenal production of 1-alpha-hydroxylase by activated macrophages and by interferon-gamma involved in granuloma formation results in increased conversion from 25-(OH) vitamin D to 1,25-(OH)2 vitamin D and, consequently, in transient HCa and suppression of PTH secretion. Fortuitous detection of HCa in transplant recipients with pulmonary symptoms must raise suspicion of PJP or fungal infection.

Serum leptin level in geriatric patients with hip fractures: possible correlation to biochemical parameters of bone remodeling.

Osteoporosis and hip fractures are a major public health problem. Since leptin was suggested to be involved in bone remodeling, its possible involvement in fracture formation/prevention was evaluated, by determination of serum leptin level in geriatric population with hip fracture, and evaluation the relationships with biochemical parameters of bone remodeling. We studied 250 geriatric patients with hip fracture admitted to Sapir Medical Center and underwent operative treatment. Among them 172 females and 78 males, with a mean age of 81 years. Serum leptin level of this total population distributed between 1 and 134ng/ml. 40% of patients were in the normal range of our laboratory (10-40ng/ml), 40% had decreased leptin level (<10ng/ml) and 20% had higher leptin level (>40ng/ml). No correlation was detected between serum leptin level and vitamin D-25(OH)D3, which was under normal range in 60% of the patients. Leptin also did not correlate to ICTP level, which was high in 80% of the patients, suggesting an extensive bone resorption in this population. Evaluation of leptin level in female versus male suggests that leptin level is higher in females than males also in this age (28.4ng/ml vs. 14.4ng/ml, p<0.001). However, no difference were detected in either ICTP, or 25(OH)D3, which are involved in bone remodeling. The higher leptin levels in women was accompanied by higher serum levels of glucose, albumin, Ca, cholesterol, Na and FT4. Comparison of 50 patients with the lowest leptin levels (mean of 3.4ng/ml) to 50 patients with highest leptin levels (mean of 34ng/ml), did not indicate differences in both 25(OH)D3 and ICTP between these two populations in spite of the highly significant difference in leptin levels. The high range of serum leptin concentration in these geriatric patients with hip fracture of both sexes, and the absence of any correlation between leptin and the tested parameters of bone resorption and Ca metabolism, teleopeptide type I collagen (ICTP) and 25(OH)D3, does not support a direct massive involvement of serum leptin in hip fracture of the very old population.