Effect of atrial natriuretic peptide on ischemia-reperfusion injury in a porcine total hepatic vascular exclusion model

AIM： To evaluate the effect of ANP on warm I/R injury in a porcine THVE model.METHODS： Miniature pigs （mini-pigs） weighing 16-24 kg were observed for 120 min after reperfusion following 120 min of THVE. The animals were divided into two groups. ANP （0.1 μg/kg per min） was administered to the ANP group （n = 7）, and vehicle was administered to the control group （n = 7）. Either vehicle or ANP was intravenously administered from 30 min before the THVE to the end of the experiment. Arterial blood was collected to measure AST, LDH, and TNF-α. Hepatic tissue blood flow （HTBF） was also measured. Liver specimens were harvested for p38 MAPK analysis and histological study. Those results were compared between the two groups.RESULTS： The AST and LDH levels were lower in the ANP group than in the control group; the AST levels were significantly different between the two groups （60 min： 568.7 ± 113.3 vs 321.6 ± 60.1, P = 0.038 〈 0.05, 120 rain： 673.6± 148.2 vs 281.1±44.8, P = 0.004 〈 0.01）. No significant difference was observed in the TNF-α levels between the two groups. HTBF was higher in the ANP group, but the difference was not significant. A significantly higher level of phosphorylated p38 MAPK was observed in the ANP group compared to the control group （0min： 2.92± 1.1 vs 6.38 ±1.1,,P= 0.011 〈 0.05）.Histological tissue damage was milder in the ANP group than in the control group.CONCLUSION： Our results show that ANP has a protective role in I/R injury with p38 MAPK activation in a porcine THVE model.

Hemoperfusion with polymyxin B-immobilized fiber column improves liver function after ischemia-reperfusion injury

AIM： To investigate the usefulness of direct hemoperfusion with a polymyxin B-immobilized fiber column （DHP-PMX therapy） for warm hepatic ischemia-reperfusion （I/R） injury after total hepatic vascular exclusion （THVE） using a porcine model. METHODS： Eleven Mexican hairless pigs weighing 22-38 kg were subjected to THVE for 120 min and then observed for 360 min. The animals were divided into two groups randomly： the DHP-PMX group （n = 5） underwent DHP-PMX at a flow rate of 80 mL/min for 220 min （beginning 10 rain before reperfusion）, while the control group did not （n = 6）. The rate pressure product （RPP）： heart rate x end-systolic arterial blood pressure, hepatic tissue blood flow （HTBF）, portal vein blood flow （PVBF）, and serum aspartate aminotransferase （AST） levels were compared between the two groups. RESULTS： RPP and HTBF were significantly （P 〈 0.05） higher in the DHP-PMX group than in the control group 240 and 360 min after reperfusion. PVBF in the DHP-PMX group was maintained at about 70% of the flow before ischemia and differed significantly （P 〈 0.05） compared to the control group 360 min after reperfusion. The serum AST increased gradually after reperfusion in both groups, but the AST was significantly （P 〈 0.05） lower in the DHP-PMX group 360 min after reperfusion. CONCLUSION： DHP-PMX therapy reduced the hepatic warm I/R injury caused by THVE in a porcine model.