Parenteral nutrition (PN) has revolutionized the care of patients with intestinal failure by providing nutrition intravenously. Worldwide, PN remains a standard tool of nutrition delivery in neonatal, pediatric, and adult patients. Though the benefits are evident, patients receiving PN can suffer serious cholestasis due to lack of enteral feeding and sometimes have fatal complications from liver injury and gut atrophy, including PN-associated liver disease or intestinal failure-associated liver disease. Recent studies into gut-systemic cross talk via the bile acid-regulated farnesoid X receptor (FXR)-fibroblast growth factor 19 (FGF19) axis, gut microbial control of the TGR5-glucagon-like peptide (GLP) axis, sepsis, and role of prematurity of hepatobiliary receptors are greatly broadening our understanding of PN-associated injury. It has also been shown that the composition of ω-6/ω-3 polyunsaturated fatty acids given parenterally as lipid emulsions can variably drive damage to hepatocytes and cell integrity. This manuscript reviews the mechanisms for the multifactorial pathogenesis of liver disease and gut injury with PN and discusses novel ameliorative strategies. (Nutr Clin Pract. 2020;35:63-71)

Extensive bowel resection results in short bowel syndrome. Absence of the ileocecal valve and length of remaining bowel are important prognostic factors. Such patients require total parenteral nutrition for survival, which has significant side effects, thus understanding mechanisms driving total parenteral nutrition-associated complications in short bowel syndrome is a major research focus. We hypothesized that we could develop an ambulatory total parenteral nutrition-short bowel syndrome piglet model recapitulating human short bowel syndrome for advanced research. Fourteen neonatal pigs received duodenal, jugular catheters, and a jacket with a miniaturized pump. Animals were randomly allocated to enteral nutrition ( n = 5), total parenteral nutrition only ( n = 5) or total parenteral nutrition with 75% small bowel, ileocecal valve resection, and ileo-colonic anastomosis ( n = 4). Blood, liver, and gut were analyzed. Animals underwent successful bowel resection and anastomosis. Increased bilirubin was noted in short bowel syndrome and total parenteral nutrition. Mean conjugated bilirubin (mg/dL)±SE was 0.036 ± 0.004 for enteral nutrition ( P = 0.03), 1.29 ± 0.613 for total parenteral nutrition ( P = 0.01), and 3.89 ± 0.51 for short bowel syndrome ( P = 0.000064). Linear gut density was reduced in short bowel syndrome and total parenteral nutrition vs. enteral nutrition. The mean linear gut density (g/cm)±SE for distal gut was 0.30 ± 0.02 for enteral nutrition ( P = 0.0005); 0.16 ± 0.01 for total parenteral nutrition ( P = 0.01), and 0.11 ± 0.008 for short bowel syndrome ( P = 0.0001). We noted gut adaptation in short bowel syndrome ( P = 0.015) with significant reduction in gut FXR, gut FGF19, and enhanced hepatic CyP7A1 expression in short bowel syndrome and total parenteral nutrition ( P < 0.05). We successfully created an ambulatory total parenteral nutrition-short bowel syndrome model with distal small bowel and ileocecal valve resection recapitulating human short bowel syndrome. Our model validated total parenteral nutrition-related hyperbilirubinemia and gut changes, as noted in human short bowel syndrome. This model holds great potential for future innovative research and clinical applications. Impact statement Short bowel syndrome is associated with significant comorbidities and mortality. This study is important as unlike current systems, it provides a validated piglet model which mirrors anatomical, histological, and serological characteristics observed in human SBS. This model can be used to advance knowledge into mechanistic pathways and therapeutic modalities to improve outcomes for SBS patients. This study is novel in that in addition to significant reduction in the remnant bowel and noted liver disease, we also developed a method to emulate ileocecal valve resection and described gut adaptive responses which has important clinical implications in humans.

Difficulty in primary fascial closure of the abdomen in transplant patients is a common challenge. Abdominal wall tension may have detrimental effects on the newly transplanted graft due to compression, and blood flow hindrance, potentially leading to ischemia or thrombosis and possibly graft failure. Furthermore, patients will be at risk of developing fascial ischemia and dehiscence. Myocutaneous flaps, temporary closure with silastic mesh, abdominal wall transplants, and even graft reduction, bowel resection, and splenectomies have been practiced with varying degrees of success. In this study, we present four cases of patients who underwent orthotopic liver transplantation (OLT) with bridging Vicryl knitted mesh (ETHICON VKML VICRYL-Polyglactin 910-30×30 cm) to relieve the tension during the closure. Our results show that these patients, despite having a high average Model End-Stage Liver Disease (MELD) score of 25, had a good liver function at the time of discharge and continue to upon follow-up. They had a relatively short length of stay (LOS) in both the intensive care unit (ICU) and in the hospital, an average of 3.5 days and 9 days, respectively. Our case series successfully show that utilizing a bridging Vicryl knitted mesh is a reasonable approach to attain tension-free abdominal closure in OLT with satisfying results.

Background Almost 9%of deceased donor livers are discarded as marginal donor livers (MDL) due to concern of severe ischemia reperfusion injury (IRI). Emerging data supports ferroptosis (iron regulated hepatocellular death) as an IRI driver, however lack of robust preclinical model limits therapeutic testing. In this manuscript we describe the development of a novel rigorous internal control system utilizing normothermic perfusion of split livers to test ferroptosis regulators modulating IRI. Methods Upon institutional approval, split human MDLs were placed on our normothermic perfusion machine, Perfusion Regulated Organ Therapeutics with Enhanced Controlled Testing (PROTECT), pumping arterial and portal blood. Experiment 1 compared right (UR) and left (UL) lobes to validate PROTECT. Experiment 2 assessed ferroptosis regulator Deferoxamine in Deferoxamine Agent Treated (DMAT) vs. No Agent Internal Control (NAIC) lobes. Liver serology, histology, and ferroptosis genes were assessed. Results Successful MDL perfusion validated PROTECT with no ALT or AST difference between UR and UL (∆ALT UR: 235, ∆ALT UL: 212; ∆AST UR: 576, ∆AST UL: 389). Liver injury markers increased in NAIC vs. DMAT (∆ALT NAIC: 586, ∆ALT DMAT: ‐405; ∆AST NAIC: 617, ∆AST DMAT: ‐380). UR and UL had similar expression of ferroptosis regulators RPL8,HO‐1 and HIFα. Significantly decreased intrahepatic iron (p = .038), HO‐1 and HIFα in DMAT (HO‐1 NAIC: 6.93, HO‐1 DMAT: 2.74; HIFαNAIC: 8.67, HIFαDMAT: 2.60)and no hepatocellular necrosis or immunohistochemical staining (Ki67/Cytokeratin‐7) differences were noted. Conclusion PROTECT demonstrates the therapeutic utility of a novel normothermic perfusion split liver system for drug discovery and rapid translatability of therapeutics, driving a paradigm change in organ recovery and transplant medicine. Our study using human livers, provides preliminary proof of concept for the novel role of ferroptosis regulators in driving IRI.

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