Angiotensin I‐converting enzyme is expressed by erythropoietic cells of normal and myeloproliferative bone marrow

Abstract
It is proposed that a locally active, intrinsic renin-angiotensin system (RAS) exists in the bone marrow (BM) and plays a role in regulating haematopoiesis. Angiotensin II type I receptor has been detected on erythroid burst-forming unit-derived cells; its antagonist losartan and angiotensin I-converting enzyme (ACE) inhibitors can suppress erythropoiesis. The possible role of ACE/RAS in BM was investigated by evaluating ACE expression in normal BM, several myeloproliferative disorders and myelodysplasia. Immunohistochemical studies showed that erythroid elements expressed ACE protein in both normal and disturbed haematopoiesis. The presence of ACE in erythroid cells suggests another mechanism for direct ACE inhibitor activity in erythropoiesis.