Remote effects of lower limb ischemia-reperfusion: impaired lung, unchanged liver, and stimulated kidney oxidative capacities.

Remote organ impairments are frequent and increase patient morbidity and mortality after lower limb ischemia-reperfusion (IR). We challenged the hypothesis that lower limb IR might also impair lung, renal, and liver mitochondrial respiration. Two-hour tourniquet-induced ischemia was performed on both hindlimbs, followed by a two-hour reperfusion period in C57BL6 mice. Lungs, liver and kidneys maximal mitochondrial respiration (V(max)), complexes II, III, and IV activity (V(succ)), and complex IV activity (V(TMPD)) were analyzed on isolated mitochondria. Lower limb IR decreased significantly lung V(max) (29.4 ± 3.3 versus 24 ± 3.7 µmol O2/min/g dry weight, resp.; P = 0.042) and tended to reduce V(succ) and V(TMPD). IR did not modify liver but increased kidneys mitochondrial respiration (79.5 ± 19.9 versus 108.6 ± 21.4, P = 0.035, and 126 ± 13.4 versus 142.4 ± 10.4 µmol O2/min/g dry weight for V(max) and V(succ), resp.). Kidneys mitochondrial coupling was increased after IR (6.5 ± 1.3 versus 8.8 ± 1.1, P = 0.008). There were no histological changes in liver and kidneys. Thus, lung mitochondrial dysfunction appears as a new early marker of hindlimb IR injuries in mice. Further studies will be useful to determine whether enhanced kidneys mitochondrial function allows postponing kidney impairment in lower limb IR setting.

[Vascular biology of coronary bypass grafts. Literature review]. / Biologie vasculaire des greffons coronaires. Un état des lieux.

Myocardial revascularisation by coronary bypass surgery is the treatment of choice for patients with multivessel disease. The most commonly used grafts are the internal mammary artery and the saphenous vein. Although the use of internal mammery artery grafts gives excellent results, venous grafts, with time, are subject to atheroma which affects their patency. Improved physiopathological understanding of the natural history of grafts, especially the saphenous vein grafts, has opened the field for different operative strategies to try and reduce the incidence of coronary graft disease. This paper reviews the literature concerning the biology of coronary grafts used for myocardial revascularisation and the current and future therapeutic implications of this data.