O impacto da insuficiência de vitamina D na tromboinflamação em indivíduos com obesidade

Abstract

Obesity is a complex multifactorial condition characterized by chronic low-grade inflammation associated with increased thrombotic risk. Vitamin D deficiency, frequently observed in individuals with obesity, has been associated with the aggravation of inflammatory and pro-coagulant profiles. Considering that monocytes play a central role in coagulation activation through the expression of tissue factor (TF), this study aimed to investigate the influence of vitamin D modulation on TF expression and the release of pro-coagulant extracellular vesicles (EVs) in different inflammatory contexts associated with obesity. Initially, the association between serum vitamin D levels and TF expression in circulating monocytes, as well as the secretion of pro-inflammatory cytokines, was evaluated. Subsequently, the release of pro-coagulant EVs (AnnV⁺TF⁺) and their cellular origin were analyzed by flow cytometry. Additionally, a plasma replacement model was employed, in which blood samples from eutrophic individuals were reconstituted with plasma from individuals with obesity, with or without vitamin D insufficiency, in order to assess the impact of the plasmatic microenvironment on monocytic TF expression. Further experiments were performed using plasma treated with polymyxin B and EVdepleted plasma to investigate the contribution of lipopolysaccharide (LPS) and circulating vesicles in this process. Complementarily, isolated monocytes were directly stimulated with EVs derived from individuals with obesity. Finally, monocytes from obese and eutrophic individuals were stimulated with leptin and/or lipopolysaccharide (LPS), in the presence or absence of 1,25(OH)₂D₃, and TF expression and secretion, as well as IL-1β, TNF- α and IL-8 levels, were evaluated. The results demonstrated that vitamin D insufficiency is associated with increased TF expression in monocytes in obesity, along with greater release of pro-coagulant EVs of monocytic origin. Plasma from individuals with obesity and vitamin D insufficiency induced higher TF expression compared to plasma from eutrophic individuals, an effect attenuated by polymyxin B treatment, EV depletion, and vitamin D incubation, suggesting the involvement of LPS and circulating vesicles in monocytic activation. Consistently, EVs derived from individuals with obesity were able to induce TF expression in monocytes. In ex vivo assays, 1,25(OH)₂D₃ reduced TF expression, reinforcing its modulatory role. Taken together, these findings suggest that vitamin D deficiency contributes to the amplification of thromboinflammation in obesity by promoting monocytic activation and the generation of pro-coagulant EVs involved in TF dissemination. Vitamin D modulation emerges as a potential adjuvant strategy to attenuate the pro-thrombotic state associated with obesity