Amyloidosis in pigtailed macaques (Macaca nemestrina): pathologic aspects.

Area of Science:

• Veterinary Pathology
• Primate Research
• Comparative Pathology

Background:

• Amyloidosis is a condition characterized by the abnormal deposition of amyloid proteins in various organs.
• Pigtailed macaques (Macaca nemestrina) are a relevant model for studying age-related diseases.
• Understanding amyloidosis in non-human primates can provide insights into human disease processes.

Purpose of the Study:

• To investigate the pathologic aspects and prevalence of amyloidosis in pigtailed macaques.
• To identify factors associated with amyloid deposition in this primate population.
• To characterize the type of amyloid found in affected animals.

Main Methods:

• Retrospective analysis of 248 cases of amyloidosis in pigtailed macaques.
• Histopathologic examination of affected tissues (spleen, liver, gastrointestinal tract).
• Histochemical testing for amyloid typing (Type AA).

Main Results:

• Amyloid was detected in the spleen, liver, and/or gastrointestinal tract in nearly 75% of the macaques studied.
• Amyloid occurrence showed age-related variations: decreasing in the spleen and GI tract, but increasing in the liver.
• Intestinal inflammation, retroperitoneal fibromatosis, enteritis, enterocolitis, and glomerulonephritis were significantly associated with gastrointestinal amyloid deposition.
• Forty cases with chronic diarrhea were identified as having Type AA amyloid.

Conclusions:

• Amyloidosis is a common finding in aged pigtailed macaques, affecting multiple organs.
• Specific inflammatory conditions and age are key factors influencing amyloidosis development in these primates.
• Type AA amyloid is the predominant form in macaques presenting with chronic diarrhea.