As a follow up to the blog on heart disease in chimpanzees, a reader asked if chimpanzees ever develop congestive heart failure. The answer is yes, this is a common cause of death in these animals. However, the pathology differs from humans. For humans, heart disease usually results from coronary artery atherosclerosis, which blocks the blood supply to the heart muscle resulting in reduced or diminished oxygen and nutrient delivery. In contrast, heart disease in chimpanzees is more commonly attributed to interstitial myocardial fibrosis whose origins are unknown. Moreover, the typical atherosclerosis-mediated heart disease seen in humans is rarely observed in apes despite their close evolutionary relationship with humans.
- The above image shows healthy heart (i.e. cardiac) muscle tissue from a human (left) and a chimpanzee (right). Figure from: Varki et al., Evol Appl. 2:101-112, 2009.
The above image shows sections of cardiac muscle tissue with Masson's Trichrome stain for collagen (blue) fibers. Note how the heart tissue from the chimpanzee (right) has more collagen fibers compared to the human sample (left). Figure from: Varki et al., Evol Appl. 2:101-112, 2009.
This image shows an atherosclerotic coronary artery from a human (left) compared with a similar coronary artery from a chimpanzee. Figure from: Varki et al., Evol Appl. 2:101-112, 2009.
Varki N, Anderson D, Herndon JG, Pham T, Gregg CJ, Cheriyan M, Murphy J, Strobert E, Fritz J, Else JG, and Varki A. Heart disease is common in humans and chimpanzees, but is caused by different pathological processes. Evol Appl. 2:101-112, 2009.