Subject(s)
Calciphylaxis/etiology , Protein S Deficiency/etiology , Renal Dialysis/adverse effects , Calciphylaxis/drug therapy , Calciphylaxis/pathology , Female , Heparin, Low-Molecular-Weight/therapeutic use , Humans , Hyperparathyroidism, Secondary/etiology , Kidney Failure, Chronic/complications , Kidney Failure, Chronic/therapy , Middle Aged , Protein S Deficiency/metabolism , Protein S Deficiency/pathology , Skin/pathologyABSTRACT
Vascular calcifications are frequent in hemodialysis patients. Its incidence ranges from 25 to 67% depending of different series. Thirty hemodialysis patients were selected from a dialysis population of 150 patients. These 30 patients were divided into two groups: group I included 15 hemodialysis patients with severe secondary hyperparathyroidism and severe, roentgenographically visible diffuse vascular calcifications, and group II included 15 other hemodialysis patients with moderate hyperparathyroidism without radiographic evidence of arterial calcifications. The control group comprised 20 normal volunteers. In all patients, measurements of protein C activity, free protein S and intact parathyroid hormone (PTH) were performed. Statistical analysis showed that free protein S in the patients of group I had a tendency to be lower than in the patients of group II (p < 0.01) and the control group (p < 0.001). We did not find significant differences in free protein S between group II and control group patients nor a significant correlation between intact PTH and free protein S in groups I and II. Protein C activity was found to be in the normal range in both groups. Free protein S deficiency in patients of group I would suggest a synthesis defect by impaired endothelial cells-due to vascular calcifications (?). Free protein S deficiency could increase the risk of thrombotic complications in these patients.
Subject(s)
Calcinosis/blood , Protein S Deficiency/etiology , Protein S/metabolism , Renal Dialysis/adverse effects , Vascular Diseases/blood , Adult , Calcinosis/etiology , Erythropoietin/therapeutic use , Female , Humans , Male , Middle Aged , Parathyroid Hormone/blood , Protein C/analysis , Protein S Deficiency/blood , Recombinant Proteins/therapeutic use , Reference Values , Vascular Diseases/etiologyABSTRACT
In this study, we evaluated the effect of long-term administration of daily calcium carbonate (2-4 g/day) and intermittent high oral doses of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3, 3-4 micrograms, given twice a week] in conjunction with a 3-mEq/1 calcium concentration in the dialysate for the treatment of severe secondary hyperparathyroidism in 6 hemodialysis patients. All patients had reduced serum levels of 1,25-(OH)2D3, which increased significantly (p < 0.005) reaching the maximum level in the 4th month. Serum total and ionized calcium levels significantly increased also, in relation to those before treatment. No patients developed hypercalcemia. Serum phosphorus did not significantly change during the study. Initial serum intact parathyroid hormone (PTH) (1,241 +/- 233 pg/ml, mean +/- SEM) markedly decreased after starting treatment with 1,25-(OH)2D3, being 542 +/- 174 pg/ml in the 5th month and 477 +/- 174 pg/ml in the 8th month. These changes are statistically significant (p < 0.05 and < 0.007, respectively). Alkaline phosphatase behavior was similar to that of intact PTH. A constant direct correlation between intact PTH and alkaline phosphatase and an inverse significant correlation between intact PTH and 1,25-(OH)2D3 was evidenced by us. We conclude that oral 1,25-(OH)2D3 pulse therapy is very effective in suppressing PTH secretion. The administration of calcium carbonate and the use of dialysate with a reduced calcium concentration would allow to prevent hyperphosphatemia and the administration of high oral doses of 1,25-(OH)2D3 without concomitant hypercalcemia.
