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Liver failure secondary to nonalcoholic fatty liver disease (NAFLD) has become the most common cause for liver transplantation in many parts of the world. Moreover, the prevalence of NAFLD not only increases the demand for liver transplantation, but also limits the supply of suitable donor organs because steatosis predisposes grafts to ischemia-reperfusion injury (IRI). There are currently no pharmacological interventions to limit hepatic IR injury because the mechanisms by which steatosis leads to increased injury are unclear. To identify potential novel mediators of IR injury, we used liquid chromatography and mass spectrometry to assess temporal changes in the hepatic lipidome in steatotic and non-steatotic livers after warm IRI in mice. Our untargeted analyses revealed distinct differences between the steatotic and non-steatotic response to IRI and highlighted dynamic changes in lipid composition with marked changes in glycerolipids and glycerophospholipids. These findings enhance our knowledge of the lipidomic changes that occur following IRI and provide a foundation for future mechanistic studies. A better understanding of the mechanisms underlying such changes will lead to novel therapeutic strategies to combat IR injury.

Centrilobular injury (CLI) is defined as the presence of perivenular mononuclear inflammation, hepatocyte dropout, and extravasated erythrocytes. In pediatric liver allografts, CLI has been associated with advanced fibrosis and chronic rejection (CR). We sought to better characterize the clinicopathologic features of CLI in the setting of T cell-mediated rejection (TCMR) and its association with complement component 4d (C4d) deposition. A total of 206 posttransplant pediatric patients (491 allograft liver biopsies) were available from 2000 to 2018, of which 63 patients (102 biopsies) showed evidence of TCMR and were included in the study. Of the patients, 35 (55.6%) had CLI on their initial episode of TCMR; those patients with CLI were significantly associated with the type of immunosuppression treatment (P = 0.03), severity of TCMR (P < 0.001), higher gamma-glutamyltransferase (P = 0.01), and advanced fibrosis (P = 0.03). There was a trend to shorter time interval from transplantation to presentation of CLI compared with those without CLI (P = 0.06). No difference was observed in graft or overall survival in the patients with CLI. In 20 patients with CLI, additional biopsies were available; in 45% of these patients, CLI was a persistent/recurrent finding. C4d deposition was noted in 12% of all biopsies (6 patients) with CLI. No significant correlation was noted in C4d deposition and CLI, CR, or graft/overall survival. In conclusion, CLI, although not significantly associated with worse graft survival, was significantly associated with severe TCMR and degree of fibrosis, which highlights the importance of active clinical management and follow-up for these patients.

Hepatic gluconeogenesis from amino acids contributes significantly to diabetic hyperglycemia, but the molecular mechanisms involved are incompletely understood. Alanine transaminases (ALT1 and ALT2) catalyze the interconversion of alanine and pyruvate, which is required for gluconeogenesis from alanine. We find that ALT2 is overexpressed in the liver of diet-induced obese and db/db mice and that the expression of the gene encoding ALT2 (GPT2) is downregulated following bariatric surgery in people with obesity. The increased hepatic expression of Gpt2 in db/db liver is mediated by activating transcription factor 4, an endoplasmic reticulum stress-activated transcription factor. Hepatocyte-specific knockout of Gpt2 attenuates incorporation of

Background While prior adult studies have shown that approximately 20%-38% of subjects undergoing solid-organ transplant develop neutropenia, similar analyses in pediatric subjects are scarce. Methods We conducted a retrospective chart review of liver transplant (LT) and kidney transplant (KT) recipients at our center during the period 2008-2018. All of the KT and none of the LT subjects during this time period had induction with either anti-thymocyte globulin (ATG) or basiliximab at time of transplant. Neutropenia was defined as absolute neutrophil count (ANC) value ≤1000/mm3 . Results One hundred subjects with LT and 82 subjects with KT were included. The incidence of neutropenia within the first year of transplant in KT was higher compared to LT (54.8% vs 39%, p = .01). The median number of hospitalizations (p = .001) and infectious complications (p = .04) was significantly higher only in the KT subjects who developed neutropenia (compared to those who did not). Multivariate analysis identified factors associated with severity of liver disease at transplant, namely h/o upper gastrointestinal bleeding (p = .02), weight deficit (p = .01), and pre-LT ANC (p = .01), along with high or moderate risk cytomegalovirus status (p = .05) as predictors of neutropenia in LT subjects. Female gender (p = .03) predicted neutropenia, while BK virus infection was protective for neutropenia (p = .04) in KT subjects. Conclusions The incidence of and morbidity associated with neutropenia within 1 year post-transplant is higher in KT subjects compared to LT subjects. The likely reason for this is the use of induction therapy (ATG, basiliximab) at the time of transplant in KT subjects.

Adipocyte triglyceride storage provides a reservoir of energy that allows the organism to survive times of nutrient scarcity, but excessive adiposity has emerged as a health problem in many areas of the world. Monoacylglycerol acyltransferase (MGAT) acylates monoacylglycerol to produce diacylglycerol; the penultimate step in triglyceride synthesis. However, little is known about MGAT activity in adipocytes, which are believed to rely primarily on another pathway for triglyceride synthesis. We show that expression of the gene that encodes MGAT1 is robustly induced during adipocyte differentiation and that its expression is suppressed in fat of genetically-obese mice and metabolically-abnormal obese human subjects. Interestingly, MGAT1 expression is also reduced in physiologic contexts where lipolysis is high. Moreover, knockdown or knockout of MGAT1 in adipocytes leads to higher rates of basal adipocyte lipolysis. Collectively, these data suggest that MGAT1 activity may play a role in regulating basal adipocyte FFA retention.

The prevalence of obesity-associated nonalcoholic fatty liver disease has significantly increased over the past decade, and end-stage liver disease secondary to nonalcoholic steatohepatitis has become 1 of the most common indications for liver transplantation. This both increases the demand for organs and decreases the availability of donor livers deemed suitable for transplantation. Although in the past many steatotic livers were discarded due to concerns over enhanced susceptibility to ischemia/reperfusion injury (IRI) and organ failure, the discrepancy between supply and demand has resulted in increasing use of expanded criteria donor organs including steatotic livers. However, it remains controversial whether steatotic livers can be safely used for transplantation and how best to improve the performance of steatotic grafts. We aimed to evaluate the impact of diet-induced hepatic steatosis in a murine model of IRI. Using a diet of high trans-fat, fructose, and cholesterol (HTF-C) and a diet high in saturated fats, sucrose, and cholesterol (Western diet), we were able to establish models of mixed macrovesicular and microvesicular steatosis (HTF-C) and microvesicular steatosis (Western). We found that the presence of hepatic steatosis, whether it is predominantly macrovesicular or microvesicular, significantly worsens IRI as measured by plasma alanine aminotransferase levels and inflammatory cytokine concentration, and histological evaluation for necrosis. Additionally, we report on a novel finding in which hepatic IRI in the setting of steatosis results in the induction of the necroptosis factors, receptor interacting protein kinase (RIPK) 3, RIPK1, and mixed-lineage kinase domain-like. These data lay the groundwork for additional experimentation to test potential therapeutic approaches to limit IRI in steatotic livers by using a genetically tractable system. Liver Transplantation 24 908-921 2018 AASLD.

Nonalcoholic fatty liver disease (NAFLD) encompasses a range of liver pathology ranging from simple steatosis to varying degrees of inflammation, hepatocyte injury and fibrosis. Without intervention it can progress to end-stage liver disease and hepatocellular carcinoma. Given its close association with obesity, the prevalence of NAFLD has increased dramatically worldwide. Currently, there are no FDA-approved medications for the treatment of NAFLD and although lifestyle modifications with appropriate diet and exercise have been shown to be beneficial, this has been difficult to achieve and sustain for the majority of patients. As such, the search for effective therapeutic agents is an active area of research. Peroxisome proliferator-activated receptors (PPARs) belong to a class of nuclear receptors. Because of their key role in the transcriptional regulation of glucose and lipid metabolism, PPAR ligands have been investigated as possible therapeutic agents for NAFLD. Here we review the current evidence from preclinical and clinical studies investigating the therapeutic potential of PPAR ligands for the treatment of this spectrum of liver disorders.

Summary: Macrophage-mediated inflammation is critical in the pathogenesis of non-alcoholic steatohepatitis (NASH). Here, we describe that, with high-fat, high-sucrose-diet feeding, mature TIM4pos Kupffer cells (KCs) decrease in number, while monocyte-derived Tim4neg macrophages accumulate. In concert, monocyte-derived infiltrating macrophages enter the liver and consist of a transitional subset that expresses Cx3cr1/Ccr2 and a second subset characterized by expression of Trem2, Cd63, Cd9, and Gpmnb; markers ascribed to lipid-associated macrophages (LAMs). The Cx3cr1/Ccr2-expressing macrophages, referred to as C-LAMs, localize to macrophage aggregates and hepatic crown-like structures (hCLSs) in the steatotic liver. In C-motif chemokine receptor 2 (Ccr2)-deficient mice, C-LAMs fail to appear in the liver, and this prevents hCLS formation, reduces LAM numbers, and increases liver fibrosis. Taken together, our data reveal dynamic changes in liver macrophage subsets during the pathogenesis of NASH and link these shifts to pathologic tissue remodeling.

Introduction Celiac disease (CD) management involves lifelong adherence to a gluten-free diet, making the dietician a key member in CD care. However, our institution lacked a standardized process for dietary consultation in newly diagnosed CD. Methods To understand provider CD care preferences, a 24-1 fractional factorial conjoint analysis was performed. Attributes studied (2 levels each) included type of initial follow-up gastroenterology (GI) provider, interval from diagnosis to follow-up, concurrence of initial dietary consultation with gastroenterology visit, and on-going follow-up GI provider. CD care was standardized in July 2014 to facilitate concurrent visits with the clinician and dietician during the same clinical session. Changes to mean time of dietary consultation and reliability of dietary consultation were monitored using an individual-control and G-control chart, respectively. Standard control chart rules were followed. Results Conjoint analysis identified shorter time to initial follow-up visit and concurrent GI/dietician visits as more important attributes in newly diagnosed CD subjects' care. Types of follow-up provider during first or subsequent visits were identified as less important attributes. After initiation of a standardized follow-up process, a special cause was identified in December 2015 with a decrease in the mean time to dietary consultation from 30 to 20 days. In addition, standardized follow-up resulted in a more reliable process as evident by a special cause on the G-control chart in February 2015. Conclusion Conjoint analysis identified attributes thought to be important in CD follow-up care. After redesign of our care process, a decrease in time to dietary consultation with improved reliability was observed.