25-hydroxyvitamin-d-2 and Kidney-Failure--Chronic

Disturbances in vitamin D metabolism are common in patients with end-stage renal disease and may contribute to vascular dysfunction.. Cross-sectional.. We evaluated 558 of 602 participants at baseline of the Hemodialysis Fistula Maturation (HFM) Study, a 7-center prospective cohort study of a cohort of patients with chronic kidney disease awaiting arteriovenous fistula (AVF) creation surgery.. 4 vitamin D metabolites measured with liquid chromatography-tandem mass spectroscopy from samples obtained within 4 weeks prior to AVF surgery.. Vasodilator functions and measurements of arterial stiffness.. Trained HFM Study personnel measured brachial artery flow-mediated dilation, nitroglycerin-mediated dilation, and carotid-femoral and carotid-radial pulse wave velocities (PWVs) prior to AVF creation. We evaluated associations after basic adjustment for sex, age, and clinical site and more fully adjusted additionally for baseline education, smoking, body mass index, diabetes, dialysis status, and medication use.. Mean participant age was 55±13 (SD) years and 65% were receiving maintenance dialysis. None of the vitamin D metabolites were significantly associated with flow-mediated dilation, carotid-femoral PWV, or carotid-radial PWV in basic or fully adjusted analyses. Higher serum concentrations of bioavailable vitamin D and 1,25-dihydroxyvitamin D were associated with 0.62% and 0.58% greater nitroglycerin-mediated dilation values, respectively, in basic models; however, these associations were no longer statistically significant with full adjustment. There were no significant associations of vitamin D metabolites with carotid-femoral or carotid-radial PWV in fully adjusted analyses.. Cross-sectional ascertainment of vitamin D metabolites and vascular functions late during the course of kidney disease.. Serum concentrations of vitamin D metabolites are not associated with vasodilator functions or vascular stiffness at baseline in a cohort study of patients with chronic kidney disease awaiting AVF creation surgery. Laboratory measurements of vitamin D metabolites are unlikely to provide useful information regarding vascular functions in this setting.

Topics: 25-Hydroxyvitamin D 2; Adult; Aged; Anastomosis, Surgical; Arteries; Brachial Artery; Calcifediol; Carotid Arteries; Chromatography, Liquid; Cohort Studies; Cross-Sectional Studies; Ergocalciferols; Female; Femoral Artery; Humans; Kidney Failure, Chronic; Male; Middle Aged; Nitroglycerin; Prospective Studies; Pulse Wave Analysis; Radial Artery; Renal Dialysis; Tandem Mass Spectrometry; Vascular Stiffness; Vasodilation; Vasodilator Agents; Veins; Vitamin D

Dietary phosphate intake and vitamin D receptor activator (VDRA) regulate fibroblast growth factor 23 (FGF23); iron may modulate FGF23 metabolism. We aimed to determine whether oral iron supplementation influences serum FGF23 concentration in hemodialysis (HD) patients, while excluding the effect of dietary phosphate intake.. This prospective study enrolled 27 maintenance HD patients with iron deficiency and hyperphosphatemia treated with sevelamer-HCl. The phosphate binder was changed from sevelamer-HCl to ferric citrate hydrate (FCH) to maintain constant phosphate levels. VDRA, other phosphate binders, and cinacalcet HCl were not changed. Serum intact FGF23, C-terminal FGF23 (C-term FGF23), intact parathyroid hormone (PTH), 1,25(OH)2D and other parameters were monitored for 12 weeks.. Serum phosphate levels (5.89 ± 1.45 mg/dl at baseline, 5.54 ± 1.35 mg/dl at 12 weeks) and 1,25(OH)2D levels were unchanged. Serum ferritin levels increased from 25.6 ± 24.3 ng/ml at baseline to 55.8 ± 33.5 ng/ml at 12 weeks with FCH administration. Serum intact FGF23 and C-term FGF23 levels significantly decreased at 12 weeks compared with baseline (2,000 (1,300.0-3,471.4) to 1,771.4 (1,142.9-2,342.9) pg/ml, p = 0.01, and 1,608.7 (634.8-2,308.7) to 1,165.2 (626.1-1,547.8) RU/ml, p = 0.007, respectively); serum intact PTH levels significantly increased (96 (65-125) to 173 (114-283) pg/ml, p < 0.001).. Oral FCH administration decreased serum intact FGF23 and C-term FGF23 levels and increased intact PTH levels; phosphate and 1,25(OH)2D levels were unchanged. Oral FCH administration to treat iron deficiency is a possible strategy for reducing serum FGF23 levels independent of phosphate and VDRA.

Topics: 25-Hydroxyvitamin D 2; Adult; Aged; Anemia, Iron-Deficiency; Bone Diseases; Chelating Agents; Female; Ferric Compounds; Fibroblast Growth Factor-23; Fibroblast Growth Factors; Humans; Kidney Failure, Chronic; Male; Middle Aged; Parathyroid Hormone; Phosphates; Prospective Studies; Renal Dialysis; Sevelamer; Young Adult

Vitamin D, estimated glomerular filtration rate (eGFR) and parathyroid hormone (PTH) are related to cardiovascular disease risk. We examined the associations between the levels of 25-hydroxyvitamin D (25-D) and 1,25-dihydroxyvitamin D (1,25-D) and both eGFR and PTH.. Cross-sectional population-based study in Kuopio, Eastern Finland.. A total of 909 men without known chronic kidney disease (CKD) and not receiving antidiabetic medication, aged from 45 to 73 years, were included in the study. Main outcome measures. Fasting levels of 25-D, 1,25-D, creatinine and PTH were measured, and an oral glucose tolerance test (OGTT) was performed.. High levels of 25-D were associated with low levels of eGFR and PTH (β = -0.17, P = 9 × 10(-7) and β = -0.28, P = 6 × 10(-17) , respectively, adjusted for age, body mass index and levels of calcium, phosphorus and glucose in a 2-h OGTT, and also for either eGFR or PTH). By contrast, high 1,25-D levels were associated with high levels of eGFR and PTH (β = 0.17, P = 2 × 10(-6) and β = 0.19, P = 5 × 10(-8) , respectively, adjusted as mentioned earlier and additionally for 25-D). Eighteen per cent of men in the highest 25-D quartile were in the lowest 1,25-D quartile and also had a lower eGFR than men with high levels of both 25-D and 1,25-D (P = 4 × 10(-5) ). Finally, 15% of men in the lowest 25-D quartile were in the highest 1,25-D quartile and also had higher PTH levels than men with low levels of both 25-D and 1,25-D (P = 2 × 10(-3) ).. Our findings suggest that both eGFR and PTH are significantly associated with vitamin D metabolism in men without known CKD.

Topics: 25-Hydroxyvitamin D 2; Aged; Algorithms; Analysis of Variance; Biomarkers; Cardiovascular Diseases; Creatinine; Cross-Sectional Studies; Finland; Glomerular Filtration Rate; Glucose Tolerance Test; Humans; Kidney Failure, Chronic; Male; Middle Aged; Multivariate Analysis; Parathyroid Hormone; Regression Analysis; Risk Factors; Sampling Studies; Surveys and Questionnaires; Vitamin D; Vitamins

Topics: 25-Hydroxyvitamin D 2; Cardiovascular Diseases; Glomerular Filtration Rate; Humans; Kidney Failure, Chronic; Male; Parathyroid Hormone; Vitamin D; Vitamins

We report a case of a male aged 50 years who consulted for renal disease recurrent lithiasis and nephrocalcinosis. The clinical examination showed external signs of rickets/osteomalacia and biochemical data as well as a severe loss of renal phosphate with hypophosphatemia, normal 25 OH vitamin D, high 1,25 OH vitamin D and hypercalciuria. Parathyroid hormone was low and renal ultrasound confirmed the existence of severe bilateral medullary nephrocalcinosis. They also found incipient chronic renal failure and incomplete renal tubular acidosis, both secondary to nephrocalcinosis and unrelated to the underlying disease. The molecular study found a change in homozygosity in intron 5 of gene SLC34A3 (NM_080877.2:c[ 448 +5G>A] + [ 448 +5G>A] ). His three children were carriers of the same variant in heterozygosis and although they were clinically asymptomatic two of them had hypercalciuria. All these data suggest that the patient had hereditary hypophosphataemic rickets with hypercalciuria (HHRH) secondary to an alteration in the sodium dependent phosphate cotransporter located in proximal tubule (NaPi-IIc). The HHRH is transmitted by autosomal recessive inheritance and is an extremely rare form of hypophosphatemic rickets. The diagnosis and treatment are essential to prevent bone sequelae of rickets and nephrocalcinosis. A correct differential diagnosis with other forms of hypophosphatemic rickets has implications on the treatment, as the management based only on phosphorus supplementation usually corrects all clinical and biochemical abnormalities, except for the loss of phosphorus in the urine. The exogenous supply of calcitriol, as advised in other hypophosphatemic rickets, may induce renal calcium deposits and nephrocalcinosis and worsens the prognosis.

Topics: 25-Hydroxyvitamin D 2; Acidosis, Renal Tubular; Calcitriol; Calcium; Cell Membrane; Familial Hypophosphatemic Rickets; Genotype; Humans; Hypercalciuria; Introns; Kidney; Kidney Failure, Chronic; Kidney Tubules, Proximal; Male; Middle Aged; Nephrocalcinosis; Nephrolithiasis; Parathyroid Hormone; Phosphorus; Prognosis; Sodium-Phosphate Cotransporter Proteins, Type IIc

The effect of pulse therapy on severe secondary hyperparathyroidism related to chronic renal failure has been examined in 11 patients on maintenance hemodialysis by using an oral administration of 8 micrograms of 1 alpha(OH)D maximum per week. Throughout the 10 months of this treatment, the serum levels of intact-PTH, HS-PTH, and C-PTH were followed up. Additionally, to estimate the peak level of 1,25(OH)2D, its serum concentration at 10 hours after the 1 alpha (OH)D ingestion was measured. Results have shown that the serum levels of the intact-PTH, HS-PTH, and C-PTH were lowered in 9 of these 11 patients, two of this number especially showing a marked suppression of the serum intact-PTH to a low that was near to the normal upper limit level. In the two other cases of these 11 patients, no suppression was seen in any of serum PTH levels throughout the 10 months. In the cases that showed a good response, the 1,25(OH)2D serum concentration elevated significantly, to more than 100 pg/ml at 10 hours after the 1 alpha (OH)D intake. In contrast, in the 2 cases that showed no response, no appreciable elevation in the serum concentrations was noted. Thus, since the pulse therapy using 1 alpha (OH)D decreased the serum levels of the intact-PTH, HS-PTH, and C-PTH in 9 out of the 11 cases, we have concluded that pulse therapy using 1 alpha(OH)D is a valid therapy for secondary hyperparathyroidism in patients on maintenance hemodialysis.

Topics: 25-Hydroxyvitamin D 2; Administration, Oral; Adult; Female; Humans; Hydroxycholecalciferols; Hyperparathyroidism, Secondary; Kidney Failure, Chronic; Male; Middle Aged; Parathyroid Hormone; Prodrugs; Renal Dialysis

Topics: 24,25-Dihydroxyvitamin D 3; 25-Hydroxyvitamin D 2; Calcifediol; Creatinine; Dihydroxycholecalciferols; Ergocalciferols; Humans; Kidney; Kidney Failure, Chronic; Metabolic Clearance Rate; Renal Dialysis

Serum calcium, phosphorus, calcitonin, parathyroid hormone, 25-hydroxyvitamin D (25OHD), and 1,25-dihydroxyvitamin D [1,25-(OH)2D] were measured in 6 women and 2 men with medullary carcinoma of the thyroid, 22 normal subjects, 5 patients with chronic renal failure, and 5 patients with primary hyperparathyroidism. Serum 1,25-(OH)2D levels were significantly higher in patients with primary hyperparathyroidism and lower in patients with chronic renal failure than in normal subjects. In patients with medullary carcinoma of the thyroid, the serum calcitonin levels were elevated, but the parathyroid hormone and 1,25-(OH)2D levels were within normal ranges. The serum 25OHD levels were not significantly different in any group. It is concluded that chronic elevation of serum calcitonin has no effect on the serum 1,25-(OH)2D level.

Topics: 25-Hydroxyvitamin D 2; Adolescent; Adult; Calcitonin; Calcitriol; Carcinoma; Ergocalciferols; Female; Humans; Hypoparathyroidism; Kidney Failure, Chronic; Male; Middle Aged; Thyroid Neoplasms

Topics: 25-Hydroxyvitamin D 2; Adult; Calcium; Ergocalciferols; Humans; Hydroxycholecalciferols; Kidney Failure, Chronic; Radioligand Assay; Renal Dialysis

Topics: 25-Hydroxyvitamin D 2; Adolescent; Child; Child, Preschool; Ergocalciferols; Female; Humans; Kidney Failure, Chronic; Male; Peritoneal Dialysis; Peritoneal Dialysis, Continuous Ambulatory