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The coronavirus disease 2019 (COVID-19) pandemic has led to a decrease in liver transplantation because of concerns regarding safety and healthcare resource utilization. There are scant data regarding the safety, optimal timing, and preferred postsurgical immunosuppression regimens for liver transplantation in patients recovered from COVID-19 infection. We describe our experience with one of the first reported cases of orthotopic liver transplantation in a patient who had recently recovered from COVID-19 infection. Using our experience as an example, orthotopic liver transplantation in patients that have recovered from COVID-19 may be safe.

Background and Aims: Hepatitis C virus (HCV)-infected organs are underutilized. We aimed to assess the safety and efficacy of direct-acting antiviral agents (DAAs) therapy in HCV viremic patients who are transplanted with a liver from a HCV viremic donor. Methods: We conducted a retrospective study, including patients seen from July 2015 to April 2017. HCV viremic patients transplanted with a liver from a HCV viremic donor and subsequently treated with DAAs were included. Outcomes assessed included undetectable viral load at 12 weeks after completing DAA therapy (sustained virologic response, SVR12), adverse events, and interactions with immunosuppression. Results: Twenty-four HCV viremic recipients received livers from HCV viremic donors. Median age was 63 years, and the majority (79.2%) were genotype 1a. Donors and recipients were viremic at the time of transplant. Median modified model for end-stage liver disease score was 19, and median time on the waitlist was 81 days. Median time from transplant to initiation of DAA therapy was 123 days. Several DAA regimens were used and 15 (62.5%) patients did not receive ribavirin. Treatment duration ranged from 12 to 24 weeks. Twenty-three (95.8%) patients achieved SVR12. Five (20.8%) patients developed adverse events; however, none required DAA discontinuation. Conclusions: DAA therapy was efficacious and well tolerated in HCV viremic recipients who underwent liver transplantation from a HCV viremic donor.

Background and aims Hepatitis C virus (HCV)-viremic organs are underutilized, and there is limited real-world experience on the transplantation of HCV-viremic solid organs into recipients who are HCV negative. Approach and results Patients listed or being evaluated for solid organ transplant after January 26, 2018, were educated and consented by protocol on the transplantation of HCV-viremic organs. All recipients were HCV nucleic acid test and anti-HCV antibody negative at the time of transplant and received an HCV-viremic organ. The primary outcome was sustained virological response (SVR) at 12 weeks after completion of direct-acting antiviral (DAA) therapy (SVR12 ). Seventy-seven patients who were HCV negative underwent solid organ transplantation from a donor who was HCV viremic. No patients had evidence of advanced hepatic fibrosis. Treatment regimen and duration were at the discretion of the hepatologist. Sixty-four patients underwent kidney transplant (KT), and 58 KT recipients had either started or completed DAA therapy. Forty-one achieved SVR12 , 10 had undetectable viral loads but are not eligible for SVR12 , and 7 remain on treatment. One KT recipient was a nonresponder because of nonstructural protein 5A resistance. Four patients underwent liver transplant and 2 underwent liver-kidney transplant. Three patients achieved SVR12 , 1 has completed DAA therapy, and 2 remain on treatment. Six patients underwent heart transplant and 1 underwent heart-kidney transplant. Six patients achieved SVR12 and 1 patient remains on treatment. Conclusions Limited data exist on the transplantation of HCV-viremic organs into recipients who are HCV negative. Our study is the largest to describe a real-world experience of the transplantation of HCV-viremic organs into recipients who are aviremic. In carefully selected patients, the use of HCV-viremic grafts in the DAA era appears to be efficacious and well tolerated.

Immune depression after trauma-hemorrhage has been implicated as an important factor in the pathogenesis of sepsis and septic-organ failure. Although recent studies have implicated immune-cell apoptosis as an important factor in the evolution of this posttrauma immune-suppressed state, neither the initial triggers that induce this response nor the cellular pathways through which these triggering pathways act have been fully defined. Thus, the current study tests the hypothesis that acute splenic and thymic immune-cell apoptosis developing after trauma-hemorrhagic shock (T/HS) is due to gut-derived factors carried in intestinal lymph and that this T/HS lymph-induced immune depressed state is mediated through Toll-like receptor 4 (TLR4). The first set of experiments documented that T/HS caused both thymic and splenic immune-cell apoptosis as measured by TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) and caspase-3 immunohistochemistry and that this increase in apoptosis was totally abrogated by mesenteric lymph duct ligation. In subsequent experiments, mesenteric lymph collected from animals subjected to T/HS or trauma-sham shock were injected into TLR4-deficient (TLR4mut) mice or their wild-type (WT) littermates. Trauma-hemorrhagic shock, but not trauma-sham shock, lymph caused splenic apoptosis in the WT mice. However, the TLR4mut mice were resistant to T/HS lymph-induced splenic apoptosis. Furthermore, the WT, but not the TLR4mut mice developed splenic apoptosis after actual T/HS. In conclusion, gut-derived factors appear to initiate a sequence of events that leads to an acute increase in splenic and thymic immune-cell apoptosis, and this process is TLR4-dependent.

Interactions of toll-like receptors (TLRs) with nonmicrobial factors play a major role in the pathogenesis of early trauma-hemorrhagic shock (T/HS)-induced organ injury and inflammation. Thus, we tested the hypothesis that TLR4 mutant (TLR4 mut) mice would be more resistant to T/HS-induced gut injury and polymorphonuclear neutrophil (PMN) priming than their wild-type littermates and found that both were significantly reduced in the TLR4 mut mice. In addition, the in vivo and ex vivo PMN priming effect of T/HS intestinal lymph observed in the wild-type mice was abrogated in TLR4 mut mice as well the TRIF mut-deficient mice and partially attenuated in Myd88 mice, suggesting that TRIF activation played a more predominant role than MyD88 in T/HS lymph-induced PMN priming. Polymorphonuclear neutrophil depletion studies showed that T/HS lymph-induced acute lung injury was PMN dependent, because lung injury was totally abrogated in PMN-depleted animals. Because the lymph samples were sterile and devoid of endotoxin or bacterial DNA, we investigated whether the effects of T/HS lymph was related to endogenous nonmicrobial TLR4 ligands. High-mobility group box 1 protein 1, heat shock protein 70, heat shock protein 27, and hyaluronic acid all have been implicated in ischemia-reperfusion-induced tissue injury. None of these "danger" proteins appeared to be involved, because their levels were similar between the sham and shock lymph samples. In conclusion, TLR4 activation is important in T/HS-induced gut injury and in T/HS lymph-induced PMN priming and lung injury. However, the T/HS-associated effects of TLR4 on gut barrier dysfunction can be uncoupled from the T/HS lymph-associated effects of TLR4 on PMN priming.

Gut injury and loss of normal intestinal barrier function are key elements in the paradigm of gut-origin systemic inflammatory response syndrome, acute lung injury, and multiple organ dysfunction syndrome (MODS). As hypoxia-inducible factor (HIF-1) is a critical determinant of the physiological and pathophysiological response to hypoxia and ischemia, we asked whether HIF-1 plays a proximal role in the induction of gut injury and subsequent lung injury. Using partially HIF-1α-deficient mice in an isolated superior mesenteric artery occlusion (SMAO) intestinal ischemia reperfusion (I/R) injury model (45 min SMAO followed by 3 h of reperfusion), we showed a direct relationship between HIF-1 activation and intestinal I/R injury. Specifically, partial HIF-1α deficiency attenuated SMAO-induced increases in intestinal permeability, lipid peroxidation, mucosal caspase-3 activity, and IL-1β mRNA levels. Furthermore, partial HIF-1α deficiency prevented the induction of ileal mucosal inducible nitric oxide synthase (iNOS) protein levels after SMAO and iNOS deficiency ameliorated SMAO-induced villus injury. Resistance to SMAO-induced gut injury was also associated with resistance to lung injury, as reflected by decreased levels of myeloperoxidase, IL-6 and IL-10 in the lungs of HIF-1α+/− mice. In contrast, a short duration of SMAO (15 min) followed by 3 h of reperfusion neither induced mucosal HIF-1α protein levels nor caused significant gut and lung injury in wild-type or HIF-1α+/− mice. This study indicates that intestinal HIF-1 activation is a proximal regulator of I/R-induced gut mucosal injury and gut-induced lung injury. However, the duration and severity of the gut I/R insult dictate whether HIF-1 plays a gut-protective or deleterious role.

Background We tested the hypothesis that testosterone depletion or blockade in male rats protects against trauma hemorrhagic shock-induced distant organ injury by limiting gut injury and subsequent production of biologically active mesenteric lymph. Methods Male, castrated male, or flutamide-treated rats (25 mg/kg subcutaneously after resuscitation) were subjected to a laparotomy (trauma), mesenteric lymph duct cannulation, and 90 minutes of shock (35 mm Hg) or trauma sham-shock. Mesenteric lymph was collected preshock, during shock, and postshock. Gut injury was determined at 6 hours postshock using ex vivo ileal permeability with fluorescein dextran. Postshock mesenteric lymph was assayed for biological activity in vivo by injection into mice and measuring lung permeability, neutrophil activation, and red blood cell deformability. In vitro neutrophil priming capacity of the lymph was also tested. Results Castrated and flutamide-treated male rats were significantly protected against trauma hemorrhagic shock (T/HS)-induced gut injury when compared with hormonally intact males. Postshock mesenteric lymph from male rats had a higher capacity to induce lung injury, Neutrophil (PMN) activation, and loss of red blood cell deformability when injected into naive mice when compared with castrated and flutamide-treated males. The increase in gut injury after T/HS in males directly correlated with the in vitro biological activity of mesenteric lymph to prime neutrophils for an increased respiratory burst. Conclusions After T/HS, gut protective effects can be observed in males after testosterone blockade or depletion. This reduced gut injury contributes to decreased biological activity of mesenteric lymph leading to attenuated systemic inflammation and distant organ injury.

BackgroundInjurious non-microbial factors released from the stressed gut during shocked states contribute to the development of acute lung injury (ALI) and multiple organ dysfunction syndrome (MODS). Since Toll-like receptors (TLR) act as sensors of tissue injury as well as microbial invasion and TLR4 signaling occurs in both sepsis and noninfectious models of ischemia/reperfusion (I/R) injury, we hypothesized that factors in the intestinal mesenteric lymph after trauma hemorrhagic shock (T/HS) mediate gut-induced lung injury via TLR4 activation.Methods/principal findingsThe concept that factors in T/HS lymph exiting the gut recreates ALI is evidenced by our findings that the infusion of porcine lymph, collected from animals subjected to global T/HS injury, into naïve wildtype (WT) mice induced lung injury. Using C3H/HeJ mice that harbor a TLR4 mutation, we found that TLR4 activation was necessary for the development of T/HS porcine lymph-induced lung injury as determined by Evan's blue dye (EBD) lung permeability and myeloperoxidase (MPO) levels as well as the induction of the injurious pulmonary iNOS response. TRIF and Myd88 deficiency fully and partially attenuated T/HS lymph-induced increases in lung permeability respectively. Additional studies in TLR2 deficient mice showed that TLR2 activation was not involved in the pathology of T/HS lymph-induced lung injury. Lastly, the lymph samples were devoid of bacteria, endotoxin and bacterial DNA and passage of lymph through an endotoxin removal column did not abrogate the ability of T/HS lymph to cause lung injury in naïve mice.Conclusions/significanceOur findings suggest that non-microbial factors in the intestinal mesenteric lymph after T/HS are capable of recreating T/HS-induced lung injury via TLR4 activation.

Background and Aims—There is substantial evidence that gut barrier failure is associated with distant organ injury and systemic inflammation. After major trauma or stress, the factors and mechanisms involved in gut injury are unknown. Our primary hypothesis is that loss of the intestinal mucus layer will result in injury of the normal gut that is exacerbated by the presence of luminal pancreatic proteases. Our secondary hypothesis is that the injury produced in the gut will result in the production of biologically active mesenteric lymph and consequently distant organ (i.e., lung) injury. Methods—To test this hypothesis, five groups of rats were studied: 1) un-instrumented naive rats; 2) control rats, in which a ligated segment of distal ileum was filled with saline; 3) rats with pancreatic proteases placed in their distal ileal segments; 4) rats with the mucolytic N-acetylcysteine (NAC) placed in their distal ileal segments and 5) rats exposed to NAC and pancreatic proteases in their ileal segments. The potential systemic consequences of gut injury induced by NAC and proteases were assessed by measuring the biologic activity of mesenteric lymph as well as gut-induced lung injury. Results—Exposure of the normal intestine to NAC, but not saline or proteases, led to increased gut permeability, loss of mucus hydrophobicity, a decrease in the mucus layer as well as morphologic evidence of villous injury. Although proteases themselves did not cause gut injury, the combination of pancreatic proteases with NAC caused more severe injury than NAC alone, suggesting that once the mucus barrier is impaired, luminal proteases can injure the now vulnerable gut. Since comparable levels of gut injury caused by systemic insults are associated with gut-induced lung injury which is mediated by biologically active factors in mesenteric lymph, we next tested whether this local model of gut injury would produce active mesenteric lymph or lead to lung injury. It did not, suggesting that gut injury by itself may not be sufficient to induce distant organ dysfunction. Conclusions—Loss of the intestinal mucus layer, especially in the presence of intra -luminal pancreatic proteases, is sufficient to lead to injury and barrier dysfunction of the otherwise normal intestine, but not to produce gut-induced distant organ dysfunction.

Background—We tested the hypothesis that females are more resistant to trauma-hemorrhagic shock (T/HS)-induced gut injury than males, and this is related to better preservation of their intestinal mucus layer, which is influenced in turn by the estrus cycle stage at the time of injury. Methods—Male, proestrus and diestrus female rats underwent a laparotomy (trauma) and 90 minutes of shock (~35 mm Hg). At 3 hours after reperfusion, terminal ileum was harvested and stained with Carnoy’s Alcian Blue for mucus assessment, hematoxylin and eosin, and periodic acid schiff for villous and goblet cell morphology and injury. Ileal permeability was measured in separate intestinal segments using the ex vivo everted gut sac technique. Results—When compared with males, proestrus female rats were significantly more resistant to T/HS-induced morphologic gut injury, as reflected in both a lower incidence of villous injury (14% vs. 22%; p < 0.05) and a lesser grade of injury (1.0 vs. 2.8; p < 0.05) as well as preservation of gut barrier function (17.9 vs. 32.2; p < 0.05). This resistance to gut injury was associated with significant preservation of the mucus layer (87% vs. 62%; p < 0.05) and was influenced by the estrus cycle stage of the female rats. There was a significant inverse correlation between mucus layer coverage and the incidence (r 2 = 0.9; p < 0.0001) and magnitude (r 2 = 0.89; p < 0.0001) of villous injury and gut permeability (r 2 = 0.74; p < 0.001). Conclusions—The resistance of female rats to T/HS-induced intestinal injury and dysfunction was associated with better preservation of the intestinal mucus barrier and was to some extent estrus cycle-dependent. Preservation of the mucus barrier may protect against shock-induced gut injury and subsequent distant organ injury by limiting the ability of luminal contents such as bacteria and digestive enzymes from coming into direct contact with the epithelium.