Comparative Pathology of Aging Great Apes

Abstract

The great apes (chimpanzees, bonobos, gorillas, and orangutans) are our closest relatives. Despite the many similarities, there are significant differences in aging among apes, including the human ape. Common to all are dental attrition, periodontitis, tooth loss, osteopenia, and arthritis, although gout is uniquely human and spondyloarthropathy is more prevalent in apes than humans. Humans are more prone to frailty, sarcopenia, osteoporosis, longevity past reproductive senescence, loss of brain volume, and Alzheimer dementia. Cerebral vascular disease occurs in both humans and apes. Cardiovascular disease mortality increases in aging humans and apes, but coronary atherosclerosis is the most significant type in humans. In captive apes, idiopathic myocardial fibrosis and cardiomyopathy predominate, with arteriosclerosis of intramural coronary arteries. Similar cardiac lesions are occasionally seen in wild apes. Vascular changes in heart and kidneys and aortic dissections in gorillas and bonobos suggest that hypertension may be involved in pathogenesis. Chronic kidney disease is common in elderly humans and some aging apes and is linked with cardiovascular disease in orangutans. Neoplasms common to aging humans and apes include uterine leiomyomas in chimpanzees, but other tumors of elderly humans, such as breast, prostate, lung, and colorectal cancers, are uncommon in apes. Among the apes, chimpanzees have been best studied in laboratory settings, and more comparative research is needed into the pathology of geriatric zoo-housed and wild apes. Increasing longevity of humans and apes makes understanding aging processes and diseases imperative for optimizing quality of life in all the ape species.

Natural mortality and cause of death analysis of the captive chimpanzee (Pan troglodytes): A 35‐year review

“…The majority of the cardiovascular cases in this report were classified as cardiomyopathy, a poorly understood entity, characterized by interstitial myocardial fibrosis. Chimpanzee cardiomyopathy is more common in males and manifests clinically as cardiac arrhythmias, sudden death, or chronic heart failure [3, 5, 6, 19, 23, 25, 27, 29]. The gastrointestinal system was the second most common affected system (14%), including four cases of hepatocellular carcinoma, and three cases each of intussusception, enteritis, and colitis.…”

“…Middle age was defined as the latter half of the interval between the start of adulthood and the start of geriatric age [24]. The lower limit of geriatric age was chosen to be 85% of total expected lifespan [24, 25] and to coincide with a prior survey of geriatric reproductive tract lesions in chimpanzees [26]. …”

Consideration of Ketogenic Metabolic Therapy as a Complementary or Alternative Approach for Managing Breast Cancer

“…It is not clear how the somatic mutation theory can account for malignant tumors that have no mutations or for normal cells and tissues that express driver mutations. 3 The absence of breast cancer and most other cancers in chimpanzees despite having about 98.5% gene and protein sequence identity with humans even at the BRCA1 locus (16)(17)(18)(19). Indeed, breast cancer has never been documented in a female chimpanzee suggesting that diet and lifestyle issues, rather than genetic mutations, are largely responsible for the disease (18,20).…”

Does selection for short sleep duration explain human vulnerability to Alzheimer’s disease?

“…In particular, among apes, humans are distinctively vulnerable to the neuronal damage associated with AD [1,6], as initially hypothesized by Stanley Rapoport [7]. While older great apes acquire modest levels of amyloid beta (Aβ) deposits at ages younger than they are observed in humans, these amyloids are typically diffuse and not associated with degenerating neurons.…”