Machine Perfusion of Livers with Moderate Macrosteatosis: Efficacy of HOPE with Controlled Rewarming

Objective. To evaluate the efficacy of machine perfusion using hypothermic oxygenated perfusion (HOPE) with controlled rewarming in reducing ischemia-reperfusion injury of human donor livers with moderate macrosteatosis through comprehensive analysis of regulated cell death mechanisms. Materials and methods. Prospective experimental study of 24 human donor livers with 30-50% macrosteatosis. Organs were randomized into three groups: control (standard cold storage, n=8), HOPE (hypothermic oxygenated perfusion at 10°C, n=8), and HOPE+W (HOPE with controlled rewarming from 10°C to 20°C, n=8). Markers of oxidative stress (MDA, GSH/GSSG), apoptosis (caspase-3, -7, -8, -9 activity, cytochrome c release), mitochondrial function (ATP production, respiratory function), inflammatory response (IL-1β, IL-6, TNF-α), and clinical transplantation outcomes were evaluated. Results. The HOPE+W group achieved significant reduction in oxidative stress markers: MDA level was 2.8±0.4 vs 5.9±0.8 nmol/mg protein in controls (p<0.001), GSH/GSSG ratio was 5.2±0.6 vs 2.1±0.3 (p<0.001). Caspase-3 activity was reduced to 0.9±0.1 vs 2.4±0.3 rel.units in controls (p<0.001). ATP production was maintained at 18.2±2.1 vs 8.4±1.2 nmol/mg/min in controls (p<0.001). IL-6 concentration in perfusate was reduced to 45±7 vs 124±16 pg/ml (p<0.001). Peak ALT levels were 524±89 vs 1248±186 U/L in controls (p<0.001). Hepatic artery thrombosis was absent (0% vs 25% in controls, p=0.034). Graft survival without retransplantation was 100% vs 75% in controls (p=0.045). Conclusion. Hypothermic oxygenated perfusion with controlled rewarming effectively protects livers with moderate macrosteatosis from ischemia-reperfusion injury through suppression of oxidative stress, preservation of mitochondrial function, inhibition of apoptosis, and modulation of inflammatory response, leading to significant improvement in early and medium-term transplantation outcomes.