EGF-GH Axis in Rat Steatotic and Non-steatotic Liver Transplantation From Brain-dead Donors

Abstract

Background. We evaluated the potential dysfunction caused by changes in growth hormone (GH) levels after brain death (BD), and the effects of modulating GH through exogenous epidermal growth factor (EGF) in steatotic and nonsteatotic grafts. Methods. Steatotic and nonsteatotic grafts from non-BD and BD rat donors were cold stored for 6 hours and transplanted to live rats. Administration of GH and EGF and their underlying mechanisms were characterized in recipients of steatotic and nonsteatotic grafts from BD donors maintained normotensive during the 6 hours before donation. Circulating and hepatic GH and EGF levels, hepatic damage, and regeneration parameters were evaluated. Recipient survival was monitored for 14 days. Somatostatin, ghrelin, and GH-releasing hormones that regulate GH secretion from the anterior pituitary were determined. The survival signaling pathway phosphoinositide-3-kinase/protein kinase B that regulates inflammation (suppressors of cytokine signaling, high-mobility group protein B1, oxidative stress, and neutrophil accumulation) was evaluated. Results. BD reduced circulating GH and increased GH levels only in steatotic livers. GH administration exacerbated adverse BD-associated effects in both types of graft. Exogenous EGF reduced GH in steatotic livers, thus activating cell proliferation and survival signaling pathways, ultimately reducing injury and inflammation. However, EGF increased GH in nonsteatotic grafts, which exacerbated damage. The benefits of EGF for steatotic grafts were associated with increased levels of somatostatin, a GH inhibitor, whereas the deleterious effect on nonsteatotic grafts was exerted through increased amounts of ghrelin, a GH stimulator. Conclusions. GH treatment is not appropriate in rat liver transplant from BD donors, whereas EGF (throughout GH inhibition) protects only in steatotic grafts.

The Effect of Fibroblast Growth Factor 15 Signaling in Non-Steatotic and Steatotic Liver Transplantation from Cardiocirculatory Death

“…The score described by Matteoni et al [28] is defined as the following types: type 1, fatty liver alone; type 2, fat accumulation and lobular inflammation; type 3, fat accumulation and ballooning degeneration; type 4, fat accumulation, ballooning degeneration, and fibrosis. As previously reported [19,24,29,30], steatosis in Zucker rats used in the current study is not associated with inflammation. Ob rats exhibited moderate macrovesicular and microvesicular fatty infiltration in hepatocytes (40-60% steatosis) but no apparent inflammation or fibrosis.…”

“…The slides were transferred to an 85% propylene glycol solution and processed for hematoxylin counterstaining. The percentage of steatosis was calculated by image analysis [24]. At least 30 high-power fields were counted per slide.…”

“…Lipid peroxidation in the intestine was determined by measuring the formation of malondialdehyde (MDA) as an indirect index of the oxidative injury induced by the reactive oxygen species [24]. Briefly, 0.5 mL of 0.5% butylated hydroxytoluene was added to 2 mL of the intestine homogenate to prevent lipid autoxidation.…”

“…After mixing and centrifuging, 1 mL of 0.67% thiobarbiturate solution was added to the supernatant and boiled for 60 min. After cooling, optical density at 530 nm was assayed [24].…”

The Role of GLP1 in Rat Steatotic and Non-Steatotic Liver Transplantation from Cardiocirculatory Death Donors

“…Nitrosylated proteins were measured using a commercial kit (Hycult Biotechnology BV, Uden, Netherlands), and NO production was determined by the accumulation of nitrites and nitrates using a spectrophotometric method according to the manufacturer's instructions (Cayman Chemicals, Ann Arbor, MI, USA) [9,14]. Lipid peroxidation was determined by measuring the formation of malondialdehyde (MDA) as an indirect index of the oxidative injury induced by the ROS [15]. Briefly, 0.5 mL of 0.5% butylated hydroxytoluene was added to 2 mL of intestine or liver homogenate to prevent lipid autoxidation.…”