Role of vascular smooth muscle cell pathobiology in sepsis‑induced vasoplegia (Review)

Sepsis‑induced vasoplegia, a life‑threatening complication of sepsis, has become a focal point of research endeavors aimed at determining its complex mechanisms. However, existing investigations predominantly focus on the role of endothelial cells (ECs) in sepsis, inadvertently dismissing the pivotal contribution of vascular smooth muscle cells (VSMCs). The present review highlights the frequently underappreciated role of VSMCs in sepsis‑induced vasodilation, and provides a comprehensive and systematic elucidation of the associated pathophysiological mechanisms. The current review examines the structural characteristics, localization, phenotypic transitions and heterogeneity of VSMCs, emphasizing their critical role in maintaining vascular homeostasis and regulating blood pressure. Subsequently, the review delves into the multifaceted effects of sepsis on VSMCs. Direct injury to VSMCs in sepsis occurs through pathogens. Additionally, the sepsis‑associated cytokine storm can activate key signaling pathways, such as the NF‑κB and p38 MAPK pathways, leading to a phenotypic shift in VSMCs from a contractile state to a synthetic state, thus enhancing their proliferative and migratory abilities. Concurrently, sepsis disrupts the intricate interaction between ECs and VSMCs, and interferes with calcium homeostasis, ultimately resulting in reduced vascular reactivity and abnormal vascular remodeling. Together, these mechanisms contribute to sepsis‑related vascular dysfunction and multiorgan failure. The in‑depth analysis of these processes in the present review offers novel insights into the pathological mechanisms of sepsis‑induced vasoplegia. The current study also provides a theoretical foundation for the development of clinical intervention strategies targeting VSMCs, with the potential to advance sepsis treatment strategies.