calcitriol and Nephrotic-Syndrome

Despite its importance in bone and cardiovascular disease in subjects with kidney disease, there are no data on fibroblast growth factor 23 (FGF23) perturbations in nephrotic syndrome. We evaluated FGF23 and markers of mineral bone metabolism in subjects with untreated NS.. In this cross-sectional study, we measured circulating levels of FGF23, 25-hydroxy vitamin D [25(OH)D], 1,25 di-hydroxy vitamin D [1,25(OH). We conclude that FGF23 is reduced in subjects with NS compared to healthy controls. The reduced levels of Vitamin D, and urinary losses may contribute to lower levels of FGF23 in NS.

Topics: Adolescent; Adult; Aged; Biomarkers; Calcium; Case-Control Studies; Creatinine; Cross-Sectional Studies; Down-Regulation; Female; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Humans; Male; Middle Aged; Nephrotic Syndrome; Parathyroid Hormone; Phosphorus; Serum Albumin, Human; Vitamin D; Young Adult

Blood levels of 25-hydroxyvitamin D [25(OH) D] are reduced in patients with nephrotic syndrome (NS). The lowering is thought to be due to urinary loss of vitamin D binding protein (DBP). A link between vitamin D deficiency and bone disease or markers of mineral metabolism has not yet been shown in NS. We hypothesized that alterations in bioavailable vitamin D levels might be linked to these abnormalities in NS.. We measured circulating levels of 25(OH)D, 1,25-dihydroxyvitamin D [1,25(OH)2 D], DBP, serum albumin and intact parathyroid hormone (iPTH) in 106 adults with sporadic idiopathic NS and 40 healthy controls. Bioavailable vitamin D was calculated from previously validated formulae. Bone mineral density (BMD) was measured at left hip (neck of femur) by DEXA.. Compared to healthy controls, total and bioavailable 25(OH)D levels were significantly reduced in patients with NS as compared to healthy controls. Among the nephrotic patients, BMD was positively correlated with bioavailable 25(OH)D (r = 0.358; P = 0.0002) but not with total 25(OH)D (r = 0.174; P = 0.079). Total 1,25(OH)2 D and bioavailable 1,25(OH)2 D did not correlate with BMD (r = 0.131; P =  0.206 and r = 0.107, P = 0.295). Bioavailable 25(OH)D levels showed a strong inverse correlation with iPTH on univariate (r = -0.457; P < 0.0001) and multivariate (β=-0.453, P < 0.0001) analyses.. We conclude that bioavailable 25(OH)D is a better measure of vitamin D status with respect of BMD and mineral metabolism in patients of nephrotic syndrome.

Topics: Absorptiometry, Photon; Adolescent; Adult; Aged; Biomarkers; Bone Density; Bone Remodeling; Case-Control Studies; Cross-Sectional Studies; Down-Regulation; Female; Femur Neck; Humans; Male; Middle Aged; Multivariate Analysis; Nephrotic Syndrome; Parathyroid Hormone; Predictive Value of Tests; Serum Albumin; Serum Albumin, Human; Vitamin D; Vitamin D Deficiency; Vitamin D-Binding Protein; Young Adult

Cross-sectional studies of children with prevalent nephrotic syndrome (NS) have shown 25-vitamin D (25(OH)D) deficiency rates of 20-100 %. Information on 25(OH)D status in incident patients or following remission is limited. This study aimed to assess 25(OH)D status of incident idiopathic NS children at presentation and longitudinally with short-term observation.. Multicenter longitudinal study of children (2-18 years old) from 14 centers across the Midwest Pediatric Nephrology Consortium with incident idiopathic NS. 25(OH)D levels were assessed at diagnosis and 3 months later.. Sixty-one children, median age 5 (3, 11) years, completed baseline visit and 51 completed second visit labs. All 61 (100 %) had 25(OH)D < 20 ng/ml at diagnosis. Twenty-seven (53 %) had 25(OH)D < 20 ng/ml at follow-up. Fourteen (28 %) children were steroid resistant. Univariate analysis showed that children prescribed vitamin D supplements were less likely to have 25(OH)D deficiency at follow-up (OR 0.2, 95 % CI 0.04, 0.6). Steroid response, age, and season did not predict 25(OH)D deficiency. Multivariable linear regression modeling showed higher 25(OH)D levels at follow-up by 13.2 ng/ml (SE 4.6, p < 0.01) in children supplemented with vitamin D.. In this incident idiopathic NS cohort, all children at diagnosis had 25(OH)D deficiency and the majority continued to have a deficiency at 2-4 months. Supplemental vitamin D decreased the odds of 25(OH)D deficiency at follow-up, supporting a role for supplementation in incident NS.

Topics: Adolescent; Biomarkers; Child; Child, Preschool; Dietary Supplements; Female; Humans; Incidence; Linear Models; Logistic Models; Longitudinal Studies; Male; Midwestern United States; Multivariate Analysis; Nephrotic Syndrome; Odds Ratio; Parathyroid Hormone; Prospective Studies; Time Factors; Treatment Outcome; Vitamin D; Vitamin D Deficiency