Fatal fasting syndrome of obese macaques.
Level 5 - mechanism / opinion, no new human data
Animal research (retrospective case series and observational study in non-human primates)
What was done
A retrospective clinical and pathological review was conducted on 42 obese macaques that died following approximately 30% body weight loss. Clinical histories were evaluated for 29 monkeys, and clinical pathology was assessed in 15. In addition, 10 rhesus monkeys were prospectively monitored after transfer to group housing, and liver biopsies were performed on 31 clinically normal obese macaques for comparison.
What was found
All 42 macaques exhibited severe fatty change of the liver and proximal convoluted renal tubular epithelium, with frequent renal tubular atrophy and pancreatic pathology (ectasia, pancreatitis, or focal necrosis). Azotemia was present in 13 of 15 clinically evaluated animals. Mean illness duration prior to death was 17 days (n=29). In 10 cases, fatal fasting syndrome lesions were the sole autopsy findings. In the prospective group, 1 of 10 monkeys died 74 days post-transfer showing only this syndrome. Among 31 healthy obese controls, only 3 had mild hepatic steatosis on biopsy. Mortality was associated with a weight loss rate of approximately 0.1 kg/day.
Why it matters
This paper identifies and defines fatal fasting syndrome in non-human primates, establishing that rapid weight loss and severe lipidosis can be fatal in obese animals following sudden anorexia or social stress.
Limits
This is an animal study in captive macaques, limiting direct clinical translation to humans. The primary analysis is retrospective with incomplete clinical history for some animals, and the precise triggers precipitating initial anorexia varied or remained undetermined.
Cited by
- supports Studies in monkeys have shown that fasting can cause detrimental effects, including worsened kidney function.