Diet-induced obesity drives negative mouse vein graft wall remodeling

IntroductionThe heightened inflammatory phenotype associated with obesity has been linked to the development of cardiovascular diseases. Short-term high-fat feeding induces a proinflammatory state that may impact the blood vessel wall. CD11c, a significantly increased dendritic cell biomarker during diet-induced obesity (DIO), may have a mechanistic role in this high-fat feeding effect. We hypothesized that the proinflammatory effect of short-term DIO accelerates vein bypass graft failure via CD11c-dependent mechanisms.MethodsMale 9-week-old DIO mice (n = 13, C57BL/6J recipients; n = 6, CD11c-/- recipients) and normal chow controls (n = 15, C57BL/6J recipients; n = 6, CD11c-/- recipients) underwent unilateral carotid interposition vein isografting (inferior vena cava from the same diet and genetic background donor), with a midgraft or outflow focal stenosis. Vein grafts were harvested at either 1 week (immunohistochemical staining for early CD11c expression) or 4 weeks later (morphometric analyses and CD11c evaluation).ResultsDespite a 40% larger body size, C57BL/6J DIO mice had 44% smaller poststenosis vein graft lumens (P = .03) than their controls via an acceleration of overall negative vein graft wall remodeling in the day-28 midgraft focal stenosis model but not in the outflow stenosis model. Higher CD11c expression occurred in DIO midgraft-stenosis vein graft walls, both at postoperative days 7 and 28. In contrast, with in vivo CD11c deficiency, DIO did not elicit this poststenotic negative remodeling but attenuated intimal hyperplasia.ConclusionsThese findings highlight negative wall remodeling as a potential factor leading to vein graft failure and provide direct evidence that short-term dietary alterations in the mammalian metabolic milieu can have lasting implications related to acute vascular interventions. DIO induces negative mouse vein graft wall remodeling via CD11c-depedent pathways.

Clinical RelevanceBrief lifestyle and dietary modifications have been associated with dramatic changes in human metabolic parameters. In the current study, short-term high-fat feeding of mice resulted in inward remodeling of vein grafts (lumen loss via wall organization into a smaller conduit), and this appeared to occur by way of a protein (CD11c) expressed on specific cell types such as dendritic cells. The findings support the relevance of the dietary-induced metabolic state of mammals to their vascular response to injury. The work also emphasizes that factors beyond the blood vessel wall likely contribute to vein graft adaptations and failure.