Background: Ferritin is a storage protein for iron that can either represent a source of iron or perform a cytoprotective action as an iron sequestrant.
Objective: To compare the concentrations of ferritin in pericardial fluid of patients with valvular heart disease, serving as controls, and in patients with coronary artery disease.
Design: We studied a total of 59 consecutive male patients undergoing elective heart valve replacement (group 1: n = 22, mean +/- SD age 55 +/- 11 years) or elective coronary artery bypass grafting (group 2: n = 37, mean +/- SD age 59 +/- 9 years).
Methods: Iron status indicators, total protein and albumin concentrations, and lactate dehydrogenase activities were determined in pericardial fluid and serum samples obtained from patients during surgery.
Results: Pericardial fluid concentrations of ferritin in both patient populations were significantly (P < 0.001) greater than the concentrations in sera: group 1, 375 (107-2030) micrograms/l compared with 146.5 (21-407) micrograms/l; group 2, 1115 (226-2500) micrograms/l compared with 152.0 (16-398) micrograms/l (median (range)), respectively. Moreover, pericardial fluid ferritin concentration was significantly (P < 0.01) greater in patients undergoing coronary artery bypass grafting than in those undergoing heart valve replacement, whereas serum ferritin concentrations did not differ between the two patient populations.
Conclusions: As pericardial fluid reflects the composition of the myocardial interstitium, we suggest that ferritin released can serve as a potential source of iron in the cardiac interstitium that may promote the generation of oxygen free radicals. Conversely, we presume that induction of ferritin synthesis, representing an important mechanism by which tissue adapts to hypoxic damage, can afford myocardial cytoprotection.