| Weight Loss in Obese C57BL/6 Mice Limits Adventitial Expansion of Established Angiotensin II-induced Abdominal Aortic Aneurysms. Am J Physiol Heart Circ Physiol. 2010 Mar 19; Authors: Police SB, Putnam K, Thatcher SE, Batifoulier-Yiannikouris F, Daugherty A, Cassis LA Previous studies demonstrated that obesity increases inflammation in periaortic adipose tissue and promotes angiotensin II (AngII)-induced AAAs. We sought to determine if weight loss of obese C57BL/6 mice would influence the progression of established AAAs. Male C57BL/6 mice were fed a high fat diet (HF) for 4 months, and then infused with either saline or AngII (1,000 ng/kg/min) for 3 months. Mice with dilated suprarenal aortas at 28 days of AngII infusion were designated to groups fed the HF (HF/HF) or a low fat diet (LF, 10% kcal as fat; HF/LF) to induce weight loss for the last 2 months of infusions. Suprarenal aortic lumen diameters of obese mice were increased by AngII infusion at day 28 (day 0: 1.03 +/- 0.02; day 28: 1.86 +/- 0.14 mm; P < 0.05), but did not progress with continued infusion in HF/HF mice. Moreover, aortic lumen diameters were not different between groups (HF/HF: 1.89 +/- 0.15; HF/LF: 1.79 +/- 0.18 mm). However, maximal diameters of excise! d AAAs were decreased with weight loss (HF/HF: 2.00 +/- 0.11; HF/LF: 1.55 +/- 0.13; P < 0.05) and had reduced adventitial areas (HF/HF: 1.18 +/- 0.10 ; HF/LF: 0.54 +/- 0.02 mm2; P<0.05). Neovascularization of aortic adventitias was strikingly decreased in HF/LF mice (HF/HF: 43 +/- 5; HF/LF: 12 +/- 2 endothelial cells/adventitial area; P< 0.05). AngII-induced elevations in adipose mRNA expression of CD105, a stromal stem cell marker, were abolished with weight loss. These results demonstrate that weight loss limits adventitial expansion of AngII-induced AAAs. Reduced neovascularization from weight loss may limit progression of AAAs. Key words: weight loss, neovascularization, aneurysms. PMID: 20304811 [PubMed - as supplied by publisher] | 
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