SERUM ALKALINE-PHOSPHATASE IN AZOTEMIC AND HEMODIALYSIS OSTEODYSTROPHY - STUDY OF ISOENZYME PATTERNS, THEIR CORRELATION WITH BONE-HISTOLOGY, AND THEIR CHANGES IN RESPONSE TO TREATMENT WITH 1-ALPHA-OHD3 AND 1,25(OH)2D3

  • 1 January 1979
    • journal article
    • research article
    • Vol. 93  (6) , 899-909
Abstract
Azotemic patients (178), 114 on hemodialysis, had measurements of total serum ALP and definition of isoenzyme patterns on acrylamide gel electrophoresis. Bone histomorphometry was defined in all of the patients by transiliac bone biopsies. Serial estimations over 2 yr were carried out on several patients, including some being treated with vitamin D2, 1.alpha.OHD3 and 1,25(OH)2D3. In both nondialyzed and dialyzed patients, serum ALP showed a significant positive correlation with osteitis fibrosa due to secondary hyperparathyroidism irrespective of the presence or absence or concurrent osteomalacia. Increases in the bone isoenzyme were largely responsible for the rise in total ALP. A higher incidence of osteomalacia (P < 0.001) was observed in patients on hemodialysis in Newcastle Upon Tyne. In hemodialyzed patients where osteomalacia was accompanied by either no secondary hyperparathyroidism (21 patients) or minimal secondary hyperparathyroidism (14 patients), serum ALP remained within normal limits, giving no indication of the existing osteomalacic bone disease. Isoenzyme studies revealed a high prevalence of the intestinal type and also varied combinations of hepatic, intestinal and bone types. Good response to vitamin D depend on the presence of significant amounts of the bone isoenzyme. Azotemic osteodystrophy characterized by a raised serum ALP and a prominent bone isoenzyme predicted a good response to vitamin D. The decrease in serum ALP following vitamin D was the result of a reduction in the bone isoenzyme. Patients with symptomatic dialysis osteomalacic bone disease, accompanied by normal total serum ALP and no elevation of the bone isoenzyme, responded less well.