Amyloid β instigates cardiac neurotrophic signaling impairment, driving Alzheimer's associated heart disease.

Abstract

While a link between cardiovascular risk factors and increased Alzheimer's disease (AD) risk has been reported, it remains unclear whether AD pathology has a direct effect on cardiac function and myocardial innervation. AD and amyloidosis are known to impair neuronal function and affect brain neurotrophic factors (NGF and BDNF) expression. Amyloid aggregates and neuro-signaling impairments may also expose AD patients to peripheral nervous system deficits, promoting cardiac disorders. Here, we characterize cardiac physiology, amyloid pathology, neurotrophic factors loss, and the impoverishment of cardiac neuronal fibers in Tg2576-AD mice hearts, human cardiomyocytes in culture, and human AD post-mortem left ventricular (LV) heart tissue. We reveal that Tg2576 animals exhibit increased myocardial fibrosis, amyloid β (Aβ) deposition, and brain/heart-axis neurotrophic deficiencies, resulting in myocardial denervation and cardiac dysfunction. Aβ oligomers reduce BDNF expression in both human immortalized and iPSC-derived cardiomyocytes, by disrupting TrkB/CREB signaling. Analysis of human LV AD post-mortem tissue confirmed cell and animal results. Our findings elucidate a previously unknown mechanism of Aβ-induced cardiac neurotrophic signaling dysregulation, underscoring the relevance of heart degeneration in AD.