Chimpanzee as model of human benign prostatic hyperplasia

Purpose: The etiology and natural history of benign prostatic hyperplasia (BPH), the most common benign disease in aging men, remain obscure. The canine BPH model has serious limitations but other animal BPH models have not been identified. We evaluated whether the chimpanzee, man's closest primate relative, developed spontaneous BPH. Materials and Methods: A cross-sectional analysis of a colony (White Sands Research Center) that contained 700 chimpanzees was undertaken by sampling 63 male and female (controls) chimpanzees 8 to 35 years old. The presence of spontaneous BPH was evaluated by assessing pathological and clinical variables, including prostate volume, serum prostate specific antigen, presence of histological BPH, serum androgens and estradiol, and urodynamics studies. Results: The chimpanzee had evidence of spontaneous histological BPH, and incidence and grade increased with age. Spontaneous BPH was manifested by increased prostate volume, higher serum prostate specific antigen, higher stromal/epithelial ratio and decreased urinary flow rates. As in man, serum androgens did not correlate with BPH in the chimpanzee. Conclusions: Male chimpanzees developed spontaneous histological BPH at the same relative point in their life cycle as humans which resulted clinically in larger prostates and decreased urinary flow rates. Serum hormone levels did not appear to correlate with BPH. A better understanding of the chimpanzee-BPH model may lead to new therapeutic strategies for BPH in man.