Plasma level of matrix metalloproteinase-9 in patients with sickle cell disease and its correlation to myocardial iron overload

Cardiac iron overload is secondary to chronic blood transfusion in patients with sickle cell disease (SCD). Iron overload cardiomyopathy is a restrictive cardiomyopathy associated with systolic and diastolic dysfunction. Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases responsible for tissue remodeling. Many studies offer strong evidence for the role of MMP-9 in LV remodeling. We aimed to detect plasma levels of MMP-9 in patients with SCD and its correlation to myocardial iron overload. A case control study was carried out on 50 patients with SCD and 50 age and sex matched healthy controls. Assessment of cardiac iron overload in patients by MRI T2* was performed. Plasma MMP-9 levels were measured for patients and controls using ELISA. SCD patients had significantly higher levels of MMP-9 than controls. There was highly significant correlation between plasma levels of MMP-9 and serum ferritin. Patients with vaso-occlusive crises (VOC) > 5/year had significantly higher levels of MMP-9 than those with VOC ≤ 5 /year. No significant correlation was found between MMP-9 and cardiac T2*. MMP-9 seems to be a useful marker in SCD patients. Patients with serum ferritin > 1000 ng/ml, recurrent VOC > 5 /year had significantly higher MMP-9 serum levels than others.