Alternate patterns of cardiac remodelling in chimpanzees ( Pan troglodytes ) living in different captive environments

Abstract

Cardiac disease is a leading cause of death in chimpanzees (Pan troglodytes), although existing data largely derive from animals housed in zoological and research facilities. To evaluate the influence of environment on cardiac health, we compared echocardiographic measures of left ventricular (LV) structure and function in age- and sex-matched chimpanzees living in a research facility and African sanctuaries (n = 144). Chimpanzees in the research facility were heavier and exhibited significantly greater LV mass and relative wall thickness, consistent with concentric LV hypertrophy. Early mitral inflow velocities were similar between groups, whereas late mitral inflow velocities were higher in research-housed chimpanzees, suggestive of impaired diastolic function. Although differences in body mass partially explained these findings, substantial group differences persisted, suggesting that additional aspects of the captive research environment contribute to adverse LV remodelling. Across the cohort, markers of altered LV structure were associated with lower indices of diastolic function, paralleling patterns observed in humans. Overall, chimpanzees housed in research facilities exhibited structural and functional cardiac changes consistent with pathological cardiac ageing, in contrast to those living in African sanctuaries. These results highlight the importance of environmental factors in chimpanzee cardiovascular health and underscore the need for longitudinal studies to disentangle the individual and combined effects of management practices on cardiac outcomes.