Macaca radiata (bonnet monkey): a spontaneous model of nonalcoholic fatty liver disease.
BACKGROUND
Nonalcoholic fatty liver disease (NAFLD) is a well-recognized condition that includes a spectrum of clinicopathology conditions ranging from steatotosis to cirrhosis and liver failure. Available animal models are not ideal as they show only a partial resemblance to characteristic human NAFLD.


OBJECTIVE
This study was aimed at identifying a nonhuman primate model of NAFLD resembling features of human NAFLD, which will be useful in understanding the mechanism of the onset of this disease and for developing novel therapeutic modalities.


METHODS
The histological status of the liver and serum levels of triglycerides (TG), cholesterol, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of aged bonnet monkeys were compared with that of the aged rhesus and adult bonnet monkeys. Histopathology and immunostaining of liver sections and oil red 'O' confirmed NAFLD in aged bonnet monkeys.


RESULTS
Aged bonnet monkeys showed a significant (P<0.01) increase in serum TG, AST and ALT compared with aged rhesus and adult bonnet monkeys. Histopathology of the liver of aged bonnet macaques showed diffused microvesicular and macrovesicular fatty changes, perivenular and portal and perisinusoidal fibrosis with fatty degeneration of hepatocytes, and immunostaining of liver sections was suggestive of NAFLD.


CONCLUSIONS
The spontaneous occurrence of NAFLD in normal animals is rare, but aged bonnet monkeys may serve as a unique animal model for studies related to NAFLD because they mimic pathophysiological features of human NAFLD.
Nagarajan
Perumal
P
Primate Research Center, National Institute of Immunology, New Delhi, India. naga73@yahoo.com
Venkatesan
Ramasamy
R
Kumar
Mahesh
M
Usmani
Abul
A
Majumdar
Subeer S
SS
D000818:Animals; D001391:Azo Compounds / Q000032:analysis; D019963:Clinical Chemistry Tests; D004396:Coloring Agents / Q000032:analysis; D004195:Disease Models, Animal; D005234:Fatty Liver / Q000097:blood / Q000473:pathology*; D005260:Female; D022781:Hepatocytes / Q000737:chemistry / Q000187:drug effects; D008099:Liver / Q000737:chemistry / Q000473:pathology*; D008255:Macaca radiata; D008297:Male; D008992:Monkey Diseases / Q000097:blood / Q000473:pathology*
D001391:Azo Compounds; D004396:Coloring Agents; C011049:oil red O