CHU Angers, Angers, France.
Vascul Pharmacol. 2013 May-Jun;58(5-6):356-62. doi: 10.1016/j.vph.2013.03.001. Epub 2013 Mar 21.
Obesity is associated with altered arterial structure and function leading to arterial narrowing in most vascular beds, especially when associated with aging. Nevertheless, mesenteric blood flow remains elevated in obese rats, although the effect of aging remains unknown. We investigated mesenteric artery narrowing following blood flow reduction in vivo in 3- and 12-month-old obese Zucker rats. After 21 days, inward remodeling occurred in low flow (LF) arteries in young and old lean rats and in young obese rats (30% diameter reduction). Diameter did not significantly decrease in old obese rats. Phenylephrine-mediated contraction was reduced by approximately 20% in LF arteries in all groups but in old obese rat arteries in which the decrease reached 80%. LF arteries expressed cyclooxygenase-2 and blood 6-keto-PGF1alpha (prostacyclin metabolite) was elevated in old obese rats. In old obese rats, acute cyclooxygenase-2 blockade restored phenylephrine-mediated contraction in LF arteries and chronic cyclooxygenase-2 blockade restored inward remodeling and contractility to control level. Thus, in old obese rats, cyclooxygenase-2-derived prostacyclin prevented the diameter reduction induced by a chronic decrease in blood flow. This adaptation is in favor of a preserved perfusion of the mesentery by contrast with other vascular territories, possibly amplifying the vascular disorders occurring in obesity.
肥胖与动脉结构和功能的改变有关，导致大多数血管床的动脉变窄，尤其是与衰老相关时。然而，肥胖大鼠的肠系膜血流仍然升高，尽管衰老的影响尚不清楚。我们研究了肥胖 Zucker 大鼠体内血流减少后肠系膜动脉的狭窄。21 天后，年轻和老年瘦大鼠以及年轻肥胖大鼠的低流量（LF）动脉发生内向重塑（直径减少 30%）。老年肥胖大鼠的直径没有显著减小。在所有组的 LF 动脉中，苯肾上腺素介导的收缩减少了约 20%，但在老年肥胖大鼠的动脉中，收缩减少了 80%。LF 动脉表达环加氧酶-2，老年肥胖大鼠的血液 6-酮-PGF1alpha（前列环素代谢物）升高。在老年肥胖大鼠中，急性环加氧酶-2 阻断可恢复 LF 动脉中苯肾上腺素介导的收缩，慢性环加氧酶-2 阻断可将内向重塑和收缩力恢复到对照水平。因此，在老年肥胖大鼠中，环加氧酶-2 衍生的前列环素可防止由慢性血流减少引起的直径减小。这种适应有利于肠系膜的灌注保持不变，与其他血管区域形成对比，可能会加剧肥胖症中发生的血管紊乱。
