Experimental peripheral arterial disease: new insights into muscle glucose uptake, macrophage, and T-cell polarization during early and late stages

Abstract

Peripheral arterial disease (PAD) is a common disease with increasing prevalence, presenting with impaired walking ability affecting patient's quality of life. PAD epidemiology is known, however, mechanisms underlying functional muscle impairment remain unclear. Using a mouse PAD model, aim of this study was to assess muscle adaptive responses during early (1 week) and late (5 weeks) disease stages. Unilateral hindlimb ischemia was induced in ApoE−/− mice by iliac artery ligation. Ischemic limb perfusion and oxygenation (Laser Doppler imaging, transcutaneous oxygen pressure assessments) significantly decreased during early and late stage compared to pre‐ischemia, however, values were significantly higher during late versus early phase. Number of arterioles and arteriogenesis‐linked gene expression increased at later stage. Walking ability, evaluated by forced and voluntary walking tests, remained significantly decreased both at early and late phase without any significant improvement. Muscle glucose uptake ([18F]fluorodeoxyglucose positron emission tomography) significantly increased during early ischemia decreasing at later stage. Gene expression analysis showed significant shift in muscle M1/M2 macrophages and Th1/Th2 T cells balance toward pro‐inflammatory phenotype during early ischemia; later, inflammatory state returned to neutrality. Muscular M1/M2 shift inhibition by a statin prevented impaired walking ability in early ischemia. High‐energy phosphate metabolism remained unchanged (31‐Phosphorus magnetic resonance spectroscopy). Results show that rapid transient muscular inflammation contributes to impaired walking capacity while increased glucose uptake may be a compensatory mechanisms preserving immediate limb viability during early ischemia in a mouse PAD model. With time, increased ischemic limb perfusion and oxygenation assure muscle viability although not sufficiently to improve walking impairment. Subsequent decreased muscle glucose uptake may partly contribute to chronic walking impairment. Early inflammation inhibition and/or late muscle glucose impairment prevention are promising strategies for PAD management.

Impact of aerobic exercise type on blood flow, muscle energy metabolism, and mitochondrial biogenesis in experimental lower extremity artery disease

“…Relative to pre-surgery assessment, total running distance during 24 h (24 h-TRD), an indicator of voluntary exercise capacity, decreased by 47.8% in all mice at 1 week post-surgery (n = 38, p < 0.0001); it is noteworthy that a 55.2% reduction in 24 h-TRD was recorded 5 weeks post-surgery in the SED mice (n = 10, p < 0.0001). These results demonstrate the effectiveness of chronic, iliac artery ligation in establishing a model of chronic hindlimb ischemia and impaired walking capacity as previously described 12 .…”

“…For oxygenation by group: 41.9 ± 7.1 mmHg, FTR; 23.9 ± 5.5 mmHg, VWR; 22.7 ± 5.8 mmHg, FS; 38.8 ± 7.2 mmHg, SED). The finding that this trend extended to the SED group of mice is attributed to, spontaneous recovery of perfusion and oxygenation of ischemic hindlimb muscle as previously reported 12 .…”

“…Unilateral (right) hindlimb ischemia was induced in 11 to 16-week old male hypercholesterolemic and atherosclerotic C57BL/6 Apolipoprotein E knock-out (ApoE −/− ) mice by surgical ligation of the right common iliac artery as previously described 12 . Under isoflurane anesthesia, this procedure necessitated only a small abdominal incision, before the right common iliac artery was exposed and ligated.…”

Inflammation in tissue engineering: The Janus between engraftment and rejection

“…M1/M2 and T H 1/T H 2 balance have been analyzed by gene expression (CD206 as M2 marker, CD11c as M1 marker, IFN-γ as T H 1 marker, and IL-4 as T H 2 marker), in a peripheral arterial disease mouse model where unilateral hindlimb ischemia was induced. Results demonstrated a significant shift from the M1 to the M2 subtype in macrophages at the ischemia site, and a further shift of T H 1/T H 2 T cells toward a proinflammatory phenotype during early ischemia, while in the later stages the gene expression profile return similar to the control, nonischemic, mouse model [61]. These polarized macrophages have been shown to strongly affect the behavior of stem cells [29,62].…”

“…muscular dystrophy) the transition from the degenerative to the regenerative phase is marked by M1 to M2 phenotype shift . A shift in macrophage polarization has been observed also during the early and late stages of hindlimb ischemia . M1/M2 and T H 1/T H 2 balance have been analyzed by gene expression (CD206 as M2 marker, CD11c as M1 marker, IFN‐γ as T H 1 marker, and IL‐4 as T H 2 marker), in a peripheral arterial disease mouse model where unilateral hindlimb ischemia was induced.…”