Serum Cholesterol Level

Total blood cholesterol values tend to be higher in captive chimpanzees than in normal humans, especially at earlier adult ages, but this result is not consistent across current colonies (1,2,3,5,6). It is unknown whether this is due to dietary differences in captivity, or other husbandry factors. Further data on high and low-density lipoproteins in chimpanzees may illuminate this variability (6). In current captive chimpanzees, the cardiac complications of the cholesterol-induced disease atherosclerosis (such as coronary thrombosis) are rare, whereas heart failure with interstitial myocardial fibrosis, but not ischemic necrosis is prevalent (5). While ischemic coronary disease was reported as common in colonies before 1980 (2), only few reports documented postmortem histopathology with myocardial necrosis (4). In view of these recent findings, it is possible that earlier studies misdiagnosed interstitial myocardial fibrosis as ischemic coronary disease. On the other hand, ischemic vascular strokes causing severe brain damage continue to occur in captive chimpanzees (7).