Taba Taba Vakili Sahar, Kailar Roshni, Rahman Khalidur, Nezami Behtash Ghazi, Mwangi Simon Musyoka, Anania Frank A, Srinivasan Shanthi
Division of Digestive Diseases, Emory University School of Medicine, Atlanta, GA.
Atlanta VA Medical Center, Decatur, GA.
Liver Transpl. 2016 Apr;22(4):459-67. doi: 10.1002/lt.24385.
Moderate macrovesicular steatosis (>30%), which is present in almost 50% of livers considered for transplantation, increases the risk of primary graft dysfunction. Our previously published data showed that glial cell line-derived neurotrophic factor (GDNF) is protective against high-fat diet (HFD)-induced hepatic steatosis in mice. Hence, we hypothesized that perfusion of steatotic livers with GDNF may reduce liver fat content before transplantation. Livers from 8 weeks of regular diet (RD) and of HFD-fed mice were perfused ex vivo for 4 hours with either vehicle, GDNF, or a previously described defatting cocktail. The liver's residual fat was quantified colorimetrically using a triglyceride (TG) assay kit and by Oil Red O (ORO) and Nile red/Hoechst staining. Liver tissue injury was assessed by using a lactate dehydrogenase (LDH) activity assay. In vitro induction of lipolysis in HepG2 cells was assessed by measuring glycerol and free fatty acid release. ORO staining showed significantly more steatosis in livers from HFD-fed mice compared with RD-fed mice (P < 0.001). HFD livers perfused with GDNF had significantly less steatosis than those not perfused (P = 0.001) or perfused with vehicle (P < 0.05). GDNF is equally effective in steatotic liver defatting compared to the defatting cocktail; however, GDNF induces less liver damage than the defatting cocktail. These observations were consistent with data obtained from assessment of liver TG content. Assessment of liver injury revealed significant hepatocyte injury in livers perfused with the control defatting cocktail but no evidence of injury in livers perfused with either GDNF or vehicle. In vitro, GDNF reduced TG accumulation in HepG2 cells and stimulated increased TG lipolysis. In conclusion, GDNF can decrease mice liver fat content to an acceptable range and could be a potential defatting agent before liver transplantation.
中度大泡性脂肪变性（>30%）在几乎50%被考虑用于移植的肝脏中存在，会增加原发性移植物功能障碍的风险。我们之前发表的数据表明，胶质细胞源性神经营养因子（GDNF）对小鼠高脂肪饮食（HFD）诱导的肝脂肪变性具有保护作用。因此，我们推测用GDNF灌注脂肪变性肝脏可能会在移植前降低肝脏脂肪含量。将来自8周常规饮食（RD）小鼠和HFD喂养小鼠的肝脏在体外分别用赋形剂、GDNF或先前描述的脱脂混合物灌注4小时。使用甘油三酯（TG）检测试剂盒以及油红O（ORO）和尼罗红/ Hoechst染色法对肝脏残余脂肪进行比色定量。通过乳酸脱氢酶（LDH）活性检测评估肝组织损伤。通过测量甘油和游离脂肪酸释放来评估HepG2细胞中脂解的体外诱导情况。ORO染色显示，与RD喂养小鼠的肝脏相比，HFD喂养小鼠的肝脏脂肪变性明显更多（P < 0.001）。用GDNF灌注的HFD肝脏的脂肪变性明显少于未灌注（P = 0.001）或用赋形剂灌注（P < 0.05）的肝脏。与脱脂混合物相比，GDNF在脂肪变性肝脏脱脂方面同样有效；然而，GDNF诱导的肝损伤比脱脂混合物少。这些观察结果与肝脏TG含量评估获得的数据一致。肝损伤评估显示，用对照脱脂混合物灌注的肝脏存在明显的肝细胞损伤，但用GDNF或赋形剂灌注的肝脏没有损伤迹象。在体外，GDNF减少了HepG2细胞中的TG积累并刺激了TG脂解增加。总之，GDNF可以将小鼠肝脏脂肪含量降低到可接受范围，并且可能是肝移植前一种潜在的脱脂剂。
