A LONGITUDINAL-STUDY ON THE EFFECT OF NIFEDIPINE THERAPY AND ITS DISCONTINUATION ON [CA2-LYMPHOCYTES OF DIALYSIS PATIENTS(]I AND PROLIFERATION OF B)

The abnormalities in cytosolic calcium ([Ca2+]i) and proliferation of B cells in uremic patients are significantly improved by treatment wit h nifedipine. The rapidity with which this agent induces its beneficia l effect and whether these derangements reemerge after cessation of th erapy are not known. We studied six hemodialysis patients before, duri ng, and after treatment with nifedipine. Before treatment, [Ca2+]i of B cells was markedly elevated (125 +/- 4.3 nmol/L) and their prolifera tion markedly reduced (5.2 +/- 0.36 x 10(3) cpm). After 1 month of the rapy, [Ca2+]i fell significantly (P < 0.01) to 95 +/- 1.7 nmol/L and t o a normal value of 84 +/- 1.6 after 2 months. The levels of [Ca2+]i r ose significantly (P < 0.01) to 95 +/- 2.3 nmol/L after 1 month of ces sation of therapy and were 115 +/- 2.8 nmol/L by 2 months, Proliferati on of B cells improved significantly (P < 0.01) after 1 month of thera py (9.4 +/- 1.1 x 10(3) cpm) with further improvement during the subse quent month, reaching a normal value (12.2 +/- 1.1 x 10(3) cpm) by the end of the 2 months. Proliferation of B cells decreased after cessati on of therapy and was 5.2 +/- 0.17 x 10(3) cpm after 2 months, a value similar to the pretreatment level. The blunted inhibitory effect of P TH-(1-84) on B cell proliferation was reversed by nifedipine treatment and reappeared after discontinuation of therapy. Also, serum globulin levels increased after administration of nifedipine and decreased aga in after cessation of treatment. The results show that nifedipine rapi dly reversed the elevation in [Ca2+]i of B cells, the impairment in th eir proliferation, and the blunted inhibitory effect of PTH on B cell proliferation, and was associated with increased serum globulin levels , These derangements reemerged after cessation of therapy. These data indicate that nifedipine therapy is effective in the management of the abnormalities in B cell metabolism and function in hemodialysis patie nts. The treatment with this drug must be maintained to sustain its be neficial effects. Other calcium channel blockers may also be effective , but their effects were not examined in the current study. (C) 1997 b y the National Kidney Foundation, Inc.