vitamin-d-2 and Nephrotic-Syndrome

Supplementation of vitamin D in food is available in Japan, therefore, vitamin D deficiency is not likely to occur in our country. But, in the case of nephrotic syndrome and strict dietary protein restriction, low serum 25(OH)D level might develop in chronic kidney disease (CKD)patients. Guideline issued by National Kidney Foundation as DOQI recommend the use of vitamin D2 (ergocalciferol) when serum 25(OH)D level in CKD patients become less than 30 ng/mL. In addition, for the CKD patients with stage 5, the use of active vitamin D3 is recommended because a conversion to 1,25(OH)2D3, which is the most potent vitamin D, might be impossible in these patients. However, vitamin D2 product as a supplementary medicine is not available in Japan unfortunately. In this context, I try to explain the background of the recommendation of vitamin D2 for CKD patients.

Topics: Biomarkers; Cholecalciferol; Diet, Protein-Restricted; Ergocalciferols; Humans; Kidney Failure, Chronic; Nephrotic Syndrome; Practice Guidelines as Topic; Vitamin D; Vitamin D Deficiency

Body stores of vitamin D are measured as "total" serum 25-hydroxy vitamin D (25(OH)D). Its largest component is protein bound and lost in urine in nephrotic syndrome (NS). Our study investigates whether "free" 25(OH)D levels are a better guide to bone health and need for vitamin D supplementation in patients with steroid-sensitive NS (SSNS).. A cross-sectional study was performed in children with SSNS and healthy controls. Blood was tested for albumin, creatinine, calcium, phosphate, ALP, total and free (by direct ELISA) 25(OH)D, iPTH, and urine for protein-creatinine ratio.. These results confirm that total 25(OH)D levels are low in NS and related to degree of proteinuria. However levels of free 25(OH)D, ALP, and iPTH did not change in relapse or remission in comparison with healthy controls. Our results suggest that in proteinuric renal diseases, free 25(OH)D rather than total 25(OH)D levels should be used to diagnose vitamin D deficiency and guide therapy.

Topics: Case-Control Studies; Child; Child, Preschool; Cholecalciferol; Cross-Sectional Studies; Dietary Supplements; Ergocalciferols; Female; Glucocorticoids; Humans; Male; Nephrotic Syndrome; Proteinuria; Risk Factors; Serum Albumin, Human; Severity of Illness Index; Vitamin D Deficiency

Although abnormalities of calcium and vitamin D metabolism are recognized in children with nephrotic syndrome, longitudinal observations are not available in these patients during periods of relapse and remission. We report observations in 58 children (mean age 10.1 years) with nephrotic syndrome and normal glomerular filtration rate. Hypocalcemia, modest hyperparathyroidism, and strikingly low calcidiol levels were identified during episodes of relapse. Most alterations were transient, and normalized on remission. The plasma concentration of calcitriol, the most active metabolite of vitamin D, was found to be normal in both relapse and remission. In the presence of hypocalcemia and hyperparathyroidism, however, normal plasma calcitriol levels in relapse may be inappropriately low and reflect a state of relative deficiency. Concurrent glucocorticoid therapy did not modify the results. A corollary of our observations is that children with relapsing or protracted nephrotic syndrome are at risk of developing metabolic bone disease, even without impairment of glomerular filtration rate.

Topics: 25-Hydroxyvitamin D 2; Adolescent; Adult; Calcium; Child; Child, Preschool; Ergocalciferols; Glomerular Filtration Rate; Humans; Hyperparathyroidism; Hypocalcemia; Nephrotic Syndrome; Parathyroid Hormone; Recurrence; Vitamin D

Patients with the nephrotic syndrome may exhibit low serum 25-OH-D concentrations. We developed a method for isolation of 25-OH-D from urine, with measurement by competitive binding assay. Daily urinary 25-OH-D excretion in healthy subjects averaged 0.17 +/- 0.15 nmol/day. Among nephrotic patients, urinary 25-OH-D excretion ranged from 0.27 to 10 nmol/day, in direct relation to the severity of proteinuria (r=0.76) and averaged 3.7 +/- 3.5 nmol/day. The 25-OH-D in the urine of nephrotic patients was unconjugated, implying that it was excreted with the serum VDBG, which has been shown to have a molecular weight and isoelectric point similar to that of albumin. We conclude that low serum 25-OH-D concentrations among nephrotic patients are principally the result or urinary losses of steroid. (J Lab Clin Med 99:325, 1982.)

Topics: 25-Hydroxyvitamin D 2; Adult; Aged; Creatinine; Ergocalciferols; Female; Humans; Male; Middle Aged; Nephrotic Syndrome; Proteinuria; Serum Albumin

Metabolic balances were used to study the intestinal absorption of calcium, magnesium and phosphate in children with steroid sensitive nephrotic syndrome in relapse. Magnesium balance was unaffected by the illness, steroid therapy, or by the addition of vitamin D. In contrast, the absorption of calcium and phosphorus was reduced by the illness and was still furthur diminished by the steroid therapy. The addition of vitamin D was totally ineffective in the doses used. The causes of these changes are discussed.

Topics: Calcium; Child; Child, Preschool; Cortisone; Drug Therapy, Combination; Ergocalciferols; Female; Humans; Hydroxycholecalciferols; Intestinal Absorption; Magnesium; Male; Nephrotic Syndrome; Phosphorus

Calcium and phosphorus balance studies were performed on 13 nephrotic patients and eight patients during clinical remission of the nephrotic syndrome. Marked impairment of intestinal absorption of calcium was found among nephrotic patients, in eight of whom faecal calcium equalled or exceeded dietary calcium. The mean faecal:dietary calcium ratio of nephrotic patients, 1-06 +/- 0-23 (SD), was significantly higher (p less than 0-005) than that of patients in remission, 0-58 +/- 0-21 (SD). The mean 24-hour urinary excretion of calcium of nephrotic patients, 0-68 +/- 0-68 (SD) mmol, was significantly lower (p less than 0-005) than that of patients in remission, 3-02 +/- 1-91 (SD) mmol. Calciferol administered to three nephrotic patients in the dosage of 1.25 mg per day did not significantly influence intestinal absorption or renal excretion of calcium. There was no difference between the two groups of patients in intestinal absorption or renal excretion of phosphorus; there was net intestinal absorption in all subjects. Quantitative bone histology was studied in seven of the nephrotic patients. None had osteomalacia or osteitis fibrosa, while only one had evidence of mild osteoporosis.

Topics: Adolescent; Adult; Bone and Bones; Calcium; Ergocalciferols; Female; Humans; Intestinal Absorption; Malabsorption Syndromes; Male; Nephrotic Syndrome; Phosphorus