INTERFERENCE OF ANGIOTENSIN-CONVERTING ENZYME-INHIBITORS ON ERYTHROPOIESIS IN KIDNEY-TRANSPLANT RECIPIENTS - ROLE OF GROWTH-FACTORS AND CYTOKINES

Background. Recent data indicate that factors other than erythropoieti n (EPO), such as insulin-like growth factor 1 (IGF-1), can promote ery thropoiesis in vitro and correct the anemia of chronic renal failure i n vivo, IGF-1 is produced by the liver under growth hormone control, a s well as by other sources, including the kidney, The erythropoietic r ole of growth factors and cytokines and their possible modulation by a ngiotensin-converting enzyme inhibitors (ACEI) has never been explored . Methods. This study evaluated;the serum levels of EPO, IGF-1, interl eukin (IL)-2, IL-3, and granulocyte macrophage-colony-stimulating fact or in 40 kidney transplanted patients with or without posttransplant e rythrocytosis (PTE) and in 10 living kidney donors. Then, the effect o f ACEI therapy on the above pattern was examined in patients with PTE. Results. EPO and IGF-1 serum levels were significantly higher in pati ents with PTE than in patients without PTE and in living kidney donor subjects, ACEI therapy significantly reduced hematocrit (Hct) as well as circulating IGF-1 and EPO levels, Of note, the decrease in IGF-1 wa s prominent mainly in those patients whose EPO levels were not signifi cantly modified by ACEI therapy, In all of the patients Hct levels dis played a direct relationship with circulating IGF-1 levels, but not wi th EPO concentration. Growth hormone did not significantly differ amon g the groups examined, whereas it steeply increased under ACEI, Finall y, no significant difference in IL-2, IL-3, and granulocyte macrophage -colony-stimulating factor serum levels was detected. Conclusions. IGF -1 seems to play a role in the ACEI-related decrease of Hct in patient s with PTE, chiefly in patients without any modification of EPO serum levels.