Induction of Senescence by Overexpression of p16 Promotes Human Microvascular Endothelial Dysfunction

Cellular senescence, a state of irreversible cell-cycle arrest in response to age or stress, has been linked to cardiovascular disease; however, its role in promoting endothelial dysfunction is unknown. Endothelial dysfunction, both in the coronary and peripheral microvasculature, is a strong predictor of future cardiac risk in humans. Here, we hypothesize that inducing endothelial cell senescence by overexpressing a key cell-cycle arrest protein, p16INK4a (p16), in human isolated microvessels from otherwise healthy adults would trigger endothelial dysfunction as evidenced by a transition in the endothelial-derived vasoactive mediator produced during shear, from nitric oxide (NO) to hydrogen peroxide (H 2 O 2 ). Human resistance arterioles (diameters 100-250µm) were isolated from otherwise discarded surgical adipose tissues and treated intraluminally with either an adeno-associated virus 2/9 (AAV2/9) to overexpress green fluorescent protein (GFP) or p16. Following a 20hr incubation, the vessels were then cannulated for pressure myography and microvascular reactivity studies. Following preconstriction with endothelin-1, internal diameters were measured in response to increased flow (pressure gradients 0-100cmH 2 O). Paired analyses were performed to limit heterogeneity. In microvessels that received p16 AAV2/9, FID was significantly impaired in the presence of PEG-catalase (20.7% of maximal dilator capacity ±2.8 (SEM), n=3, p<0.05, two-way ANOVA*) compared to GFP AAV control (60.5%±3.7, n=3), indicating that vessels overexpressing p16 relied on the generation of H 2 O 2 to elicit dilation to flow. Interestingly, overall vasodilatory capacity was reduced in arterioles with increased expression of p16 compared to GFP control (45.7%±5.6, n=3 for p16 AAV vessels* vs. GFP AAV vessels 65.7%±1.1, n=3). Together, these data suggest that endothelial cell senescence is a key mechanistic component in the development of endothelial dysfunction in the human microvasculature and may offer insight into how aging or exposure to microvascular insults damage the endothelium and increase one’s risk of future cardiovascular disease. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.