Ischemia–reperfusion injury in rat steatotic liver is dependent on NFκB P65 activation

• Published in: Transplant immunology 2012-06, Vol.26 (4), p.201-206
• Main Authors: Ramachandran, Sabarinathan, Liaw, Jane M, Jia, Jianluo, Glasgow, Sean C, Liu, Wei, Csontos, Krista, Upadhya, G.A, Mohanakumar, T, Chapman, William C
• Format: Article
• Language: English
• Subjects: Allergy and Immunology; Animals; Boronic Acids - administration & dosage; Boronic Acids - adverse effects; Bortezomib; Chemokine CXCL2 - genetics; Chemokine CXCL2 - metabolism; Disease Models, Animal; Fatty Liver - complications; Fatty Liver - drug therapy; Fatty Liver - immunology; Hepatic steatosis; Humans; I/R injury; Inflammation Mediators - metabolism; Interleukin-1beta - genetics; Interleukin-1beta - metabolism; Liver - drug effects; Liver - metabolism; Liver - pathology; Liver transplantation; Marginal graft; NFκB; Obese; Proteasome Inhibitors; PS-341; Pyrazines - administration & dosage; Pyrazines - adverse effects; Rats; Rats, Zucker; Reperfusion Injury - complications; Reperfusion Injury - drug therapy; Reperfusion Injury - immunology; Transcription Factor RelA - genetics; Transcription Factor RelA - metabolism; Tumor Necrosis Factor-alpha - genetics; Tumor Necrosis Factor-alpha - metabolism
• ISSN: 0966-3274; 1878-5492
• DOI: 10.1016/j.trim.2012.01.001

Abstract Background Steatotic liver grafts tolerate ischemia–reperfusion (I/R) injury poorly, contributing to increased primary graft nonfunction following transplantation. Activation of nuclear factor kappa-B (NFκB) following I/R injury plays a crucial role in activation of pro-inflammatory responses leading to injury. Methods We evaluated the role of NFκB in steatotic liver injury by using an orthotopic liver transplant (OLT) model in Zucker rats (lean to lean or obese to lean) to define the mechanisms of steatotic liver injury. Obese donors were treated with bortezomib to assess the role of NF-κB in steatotic liver I/R injury. Hepatic levels of NF-κB and pro-inflammatory cytokines were analyzed by ELISA. Serum transaminase levels and histopathological analysis were performed to assess associated graft injury. Results I/R injury in steatotic liver results in significant increases in activation of NF-κB (40%, p < 0.003), specifically the p65 subunit following transplantation. Steatotic donor pretreatment with proteasome inhibitor bortezomib (0.1 mg/kg) resulted in significant reduction in levels of activated NF-κB (0.58 ± 0.18 vs. 1.37 ± 0.06 O.D./min/10 μg protein, p < 0.003). Bortezomib treatment also reduced expression of pro-inflammatory cytokines MIP-2 compared with control treated steatotic and lean liver transplants respectively (106 ± 17.5 vs. 443.3 ± 49.9 vs. 176 ± 10.6 pg/mL, p = 0.02), TNF-α (223.8 ± 29.9 vs. 518.5 ± 66.5 vs. 264.5 ± 30.1 pg/2 μg protein, p = 0.003) and IL-1β (6.0 ± 0.91 vs. 19.8 ± 5.2 vs. 5 ± 1.7 pg/10 μg protein, p = 0.02) along with a significant reduction in ALT levels (715 ± 71 vs. 3712.5 ± 437.5 vs. 606 ± 286 U/L, p = 0.01). Conclusion These results suggest that I/R injury in steatotic liver transplantation are associated with exaggerated activation of NFκB subunit p65, leading to an inflammatory mechanism of reperfusion injury and necrosis. Proteasome inhibition in steatotic liver donor reduces NFκB p65 activation and inflammatory I/R injury, improving transplant outcomes of steatotic grafts in a rat model.