Induction of Skin Allograft Chimerism by Pharmacological Mobilization of Endogenous Bone Marrow-Derived Stem Cells.

Skin substitutes including allografts remain a standard therapeutic approach to promote healing of both acute and chronic large wounds. However, none have resulted in the regrowth of lost and damaged tissues and scarless wound healing. Here, we demonstrate skin allograft chimerism and repair through the mobilization of endogenous bone marrow-derived stem and immune cells in rats and swine. We show that pharmacological mobilization of bone marrow stem cells and immune cells into the circulation promotes host repopulation of skin allografts and restoration of the skin's normal architecture without scarring and minimal contracture. When skin allografts from DA rats are transplanted into GFP transgenic Lewis recipients with a combination of AMD3100 and low-dose FK506 (AF) therapy, host-derived GFP-positive cells repopulate and/or regenerate cellular components of skin grafts including epidermis and hair follicles and the grafts become donor-host chimeric skin. Using AF combination therapy, burn wounds with skin allografts were healed by newly regenerated chimeric skin with epidermal appendages and pigmentation and without contracture in swine.

Discovery and characterization of cross-reactive intrahepatic antibodies in severe alcoholic hepatitis.

The pathogenesis of antibodies in severe alcoholic hepatitis (SAH) remains unknown. We analyzed immunoglobulins (Ig) in explanted livers from SAH patients (n=45) undergoing liver transplantation and tissues from corresponding healthy donors (HD, n=10) and found massive deposition of IgG and IgA isotype antibodies associated with complement fragment C3d and C4d staining in ballooned hepatocytes in SAH livers. Ig extracted from SAH livers, but not patient serum exhibited hepatocyte killing efficacy. Employing human and Escherichia coli K12 proteome arrays, we profiled the antibodies extracted from explanted SAH, livers with other diseases, and HD livers. Compared with their counterparts extracted from livers with other diseases and HD, antibodies of IgG and IgA isotypes were highly accumulated in SAH and recognized a unique set of human proteins and E. coli antigens. Further, both Ig- and E. coli-captured Ig from SAH livers recognized common autoantigens enriched in several cellular components including cytosol and cytoplasm (IgG and IgA), nucleus, mitochondrion, and focal adhesion (IgG). Except IgM from primary biliary cholangitis livers, no common autoantigen was recognized by Ig- and E. coli-captured Ig from livers with other diseases. These findings demonstrate the presence of cross-reacting anti-bacterial IgG and IgA autoantibodies in SAH livers.

A phase I, first-in-human study to evaluate the safety and tolerability, pharmacokinetics, and pharmacodynamics of MRG-001 in healthy subjects.

Preclinical studies demonstrate that pharmacological mobilization and recruitment of endogenous bone marrow stem cells and immunoregulatory cells by a fixed-dose drug combination (MRG-001) improves wound healing, promotes tissue regeneration, and prevents allograft rejection. In this phase I, first-in-human study, three cohorts receive subcutaneous MRG-001 or placebo, every other day for 5 days. The primary outcome is safety and tolerability of MRG-001. Fourteen subjects received MRG-001 and seven received a placebo. MRG-001 is safe over the selected dose range. There are no clinically significant laboratory changes. The intermediate dose group demonstrates the most significant white blood cell, stem cell, and immunoregulatory cell mobilization. PBMC RNA sequencing and gene set enrichment analysis reveal 31 down-regulated pathways in the intermediate MRG-001 dose group compared with no changes in the placebo group. MRG-001 is safe across all dose ranges. MRG-001 may be a clinically useful therapy for immunoregulation and tissue regeneration (ClinicalTrials.gov: NCT04646603).

Discovery and characterization of cross-reactive intrahepatic antibodies in severe alcoholic hepatitis.

The pathogenesis of antibodies in severe alcoholic hepatitis (SAH) remains unknown. We sought to determine if there was antibody deposition in SAH livers and whether antibodies extracted from SAH livers were cross-reactive against both bacterial antigens and human proteins. We analyzed immunoglobulins (Ig) in explanted livers from SAH patients (n=45) undergoing liver transplantation and tissue from corresponding healthy donors (HD, n=10) and found massive deposition of IgG and IgA isotype antibodies associated with complement fragment C3d and C4d staining in ballooned hepatocytes in SAH livers. Ig extracted from SAH livers, but not patient serum exhibited hepatocyte killing efficacy in an antibody-dependent cell-mediated cytotoxicity (ADCC) assay. Employing human proteome arrays, we profiled the antibodies extracted from explanted SAH, alcoholic cirrhosis (AC), nonalcoholic steatohepatitis (NASH), primary biliary cholangitis (PBC), autoimmune hepatitis (AIH), hepatitis B virus (HBV), hepatitis C virus (HCV) and HD livers and found that antibodies of IgG and IgA isotypes were highly accumulated in SAH and recognized a unique set of human proteins as autoantigens. The use of an E. coli K12 proteome array revealed the presence of unique anti- E. coli antibodies in SAH, AC or PBC livers. Further, both Ig and E. coli captured Ig from SAH livers recognized common autoantigens enriched in several cellular components including cytosol and cytoplasm (IgG and IgA), nucleus, mitochondrion and focal adhesion (IgG). Except IgM from PBC livers, no common autoantigen was recognized by Ig and E. coli captured Ig from AC, HBV, HCV, NASH or AIH suggesting no cross-reacting anti- E. coli autoantibodies. The presence of cross-reacting anti-bacterial IgG and IgA autoantibodies in the liver may participate in the pathogenesis of SAH.

Donor BMI and Post-living Donor Liver Transplantation Outcomes: A Preliminary Report.

Living liver donor obesity has been considered a relative contraindication to living donation given the association with hepatic steatosis and potential for poor donor and recipient outcomes. We investigated the association between donor body mass index (BMI) and donor and recipient posttransplant outcomes. Methods: We studied 66 living donors and their recipients who underwent living donor liver transplant at our center between 2013 and 2020. BMI was divided into 3 categories (<25, 25-29.9, and ≥30 kg/m2). Magnetic resonance imaging-derived proton density fat fraction was used to quantify steatosis. Donor outcomes included length of stay (LOS), emergency department visits within 90 d, hospital readmissions within 90 d, and complication severity. Recipient outcomes included LOS and in-hospital mortality. The Student t test was used to compare normally distributed variables, and Kruskal-Wallis tests were used for nonparametric data. Results: There was no difference in donor or recipient characteristics based on donor BMI. There was no significant difference in mean magnetic resonance imaging fat percentage among the 3 groups. Additionally, there was no difference in donor LOS (P = 0.058), emergency department visits (P = 0.64), and hospital readmissions (P = 0.66) across BMI category. Donor complications occurred in 30 patients. There was no difference in postdonation complications across BMI category (P = 0.19); however, there was a difference in wound complications, with the highest rate being seen in the highest BMI group (0% versus 16% versus 37%; P = 0.041). Finally, there was no difference in recipient LOS (P = 0.83) and recipient in-hospital mortality (P = 0.29) across BMI category. Conclusions: Selecting donors with BMI ≥30 kg/m2 can result in successful living donor liver transplantation; however, they are at risk for perioperative wound complications. Donor counseling and perioperative strategies to mitigate wound-related issues should be used when considering obese living donors.

Exertional Heat Stroke-Induced Acute Liver Failure and Liver Transplantation.

Exertional heat stroke is a medical emergency characterized by excessive heat production and inadequate heat dissipation usually after heavy exertion in hot and humid climates and can be associated with multiorgan failure. Treatment is largely supportive, but liver transplantation (LT) may be necessary in select patients. Here, we report the case of a 44-year-old runner who was found unconscious after a 5-mile run and developed acute liver failure. He underwent successful LT 1 week later when he developed encephalopathy. This case report illustrates the importance of early LT referral in patients with exertional heat stroke-induced acute liver failure.

A Randomized Double-Blinded Placebo Controlled Trial of Clazakizumab for the Treatment of COVID-19 Pneumonia With Hyperinflammation.

OBJECTIVES: We designed this study to test whether clazakizumab, a direct interleukin-6 inhibitor, benefits patients hospitalized with severe or critical COVID-19 disease accompanied by hyperinflammation. DESIGN: Multicenter, randomized, double-blinded, placebo-controlled, seamless phase II/III trial. SETTING: Five U.S. medical centers. PATIENTS: Adults inpatients with severe COVID-19 disease and hyperinflammation. INTERVENTIONS: Eighty-one patients enrolled in phase II, randomized 1:1:1 to low-dose (12.5 mg) or high-dose (25 mg) clazakizumab or placebo. Ninety-seven patients enrolled in phase III, randomized 1:1 to high-dose clazakizumab or placebo. MEASUREMENTS AND MAIN RESULTS: The primary outcome was 28-day ventilator-free survival. Secondary outcomes included overall survival, frequency and duration of intubation, and frequency and duration of ICU admission. Per Data Safety and Monitoring Board recommendations, additional secondary outcomes describing clinical status and status changes, as measured by an ordinal scale, were added. Bayesian cumulative proportional odds, logistic, and Poisson regression models were used. The low-dose arm was dropped when the phase II study suggested superiority of the high-dose arm. We report on 152 patients, 74 randomized to placebo and 78 to high-dose clazakizumab. Patients receiving clazakizumab had greater odds of 28-day ventilator-free survival (odds ratio [OR] = 3.84; p [OR > 1] 99.9%), as well as overall survival at 28 and 60 days (OR = 1.75; p [OR > 1] 86.5% and OR = 2.53; p [OR > 1] 97.7%). Clazakizumab was associated with lower odds of intubation (OR = 0.2; p [OR] < 1; 99.9%) and ICU admission (OR = 0.26; p [OR < 1] 99.6%); shorter durations of ventilation and ICU stay (risk ratio [RR] < 0.75; p [RR < 1] > 99% for both); and greater odds of improved clinical status at 14, 28, and 60 days (OR = 2.32, p [OR > 1] 98.1%; OR = 3.36, p [OR > 1] 99.6%; and OR = 3.52, p [OR > 1] 99.8%, respectively). CONCLUSIONS: Clazakizumab significantly improved 28-day ventilator-free survival, 28- and 60-day overall survival, as well as clinical outcomes in hospitalized patients with COVID-19 and hyperinflammation.

Differential Cytokine Signatures of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and Influenza Infection Highlight Key Differences in Pathobiology.

BACKGROUND: Several inflammatory cytokines are upregulated in severe coronavirus disease 2019 (COVID-19). We compared cytokines in COVID-19 versus influenza to define differentiating features of the inflammatory response to these pathogens and their association with severe disease. Because elevated body mass index (BMI) is a known risk factor for severe COVID-19, we examined the relationship of BMI to cytokines associated with severe disease. METHODS: Thirty-seven cytokines and chemokines were measured in plasma from 135 patients with COVID-19, 57 patients with influenza, and 30 healthy controls. Controlling for BMI, age, and sex, differences in cytokines between groups were determined by linear regression and random forest prediction was used to determine the cytokines most important in distinguishing severe COVID-19 and influenza. Mediation analysis was used to identify cytokines that mediate the effect of BMI and age on disease severity. RESULTS: Interleukin-18 (IL-18), IL-1ß, IL-6, and tumor necrosis factor-α (TNF-α) were significantly increased in COVID-19 versus influenza patients, whereas granulocyte macrophage colony-stimulating factor, interferon-γ (IFN-γ), IFN-λ1, IL-10, IL-15, and monocyte chemoattractant protein 2 were significantly elevated in the influenza group. In subgroup analysis based on disease severity, IL-18, IL-6, and TNF-α were elevated in severe COVID-19, but not in severe influenza. Random forest analysis identified high IL-6 and low IFN-λ1 levels as the most distinct between severe COVID-19 and severe influenza. Finally, IL-1RA was identified as a potential mediator of the effects of BMI on COVID-19 severity. CONCLUSIONS: These findings point to activation of fundamentally different innate immune pathways in severe acute respiratory syndrome coronavirus 2 and influenza infection, and emphasize drivers of severe COVID-19 to focus both mechanistic and therapeutic investigations.

Temporal Trends in Utilization and Outcomes of DCD Livers in the United States.

BACKGROUND: Historically, donation after circulatory death (DCD) livers were frequently discarded because of higher mortality and graft loss after liver transplantation (LT). However, the demand for LT continues to outstrip the supply of "acceptable" organs. Additionally, changes in the donor pool, organ allocation, and clinical management of donors and recipients, and improved clinical protocols might have altered post-DCD-LT outcomes. METHODS: We studied 5975 recovered DCD livers using US Scientific Registry of Transplant Recipients data from 2005 to 2017, with a comparison group of 78 235 adult donation after brain death (DBD) livers recovered during the same time period. We quantified temporal trends in discard using adjusted multilevel logistic regression and temporal trends in post-LT mortality and graft loss for DCD LT recipients using adjusted Cox regression. RESULTS: DCD livers were more likely to be discarded than DBD livers across the entire study period, and the relative likelihood of discard increased over time (adjusted odds ratio [aOR] of discard DCD versus DBD 3.854.455.14 2005-2007, 5.225.876.59 2015-2017) despite improving outcomes after DCD LT. Mortality risk for DCD LTs decreased in each time period (compared with 2005-2007, aHR 2008-2011 0.720.840.97, aHR 2012-2014 0.480.580.70, aHR 2015-2017 0.340.430.55), as did risk of graft loss (compared with 2005-2007, aHR 2008-2011 0.690.810.94, aHR 2012-2014 0.450.550.67, aHR 2015-2017 0.360.450.56). CONCLUSIONS: Despite dramatic improvements in outcomes of DCD LT recipients, DCD livers remain substantially more likely to be discarded than DBD livers, and this discrepancy has actually increased over time. DCD livers are underutilized and have the potential to expand the donor pool.

Evaluation of Early vs Standard Liver Transplant for Alcohol-Associated Liver Disease.

Importance: Traditionally, liver transplant (LT) for alcohol-associated liver disease (ALD) requires 6 months of abstinence. Although early LT before 6 months of abstinence has been associated with decreased mortality for decompensated ALD, this practice remains controversial and concentrated at a few centers. Objective: To define patient, allograft, and relapse-free survival in early LT for ALD, and to investigate the association between these survival outcomes and early vs standard LT. Design, Setting, and Participants: This cohort study analyzed all patients with ALD who underwent their first LT at a single academic referral center between October 1, 2012, and November 13, 2020. Patients with known pretransplant hepatocellular carcinoma, hepatitis B or C, or an alternative cause of liver failure were excluded. Follow-up period was defined as the time from LT to the most recent encounter with a transplant center or death. Exposures: The exposure of interest was early LT, which was defined as less than 180 days of pre-LT abstinence. Standard LT was defined as 180 days or more of pre-LT abstinence. Patients were separated into early LT and standard LT by time from abstinence to LT. Main Outcomes and Measures: The outcomes were patient, allograft, relapse-free, and hazardous relapse-free survival for patients who underwent early LT or standard LT. These groups were compared by log-rank testing of Kaplan-Meier estimates. Hazardous relapse was defined as binge, at-risk, or frequent drinking. Abstinence was reassessed at the most recent follow-up visit for all patients. Results: Of the 163 patients with ALD included in this study, 88 (54%) underwent early LT and 75 (46%) underwent standard LT. This cohort had a mean (SD) age at transplant of 52 (10) years and was predominantly composed of 108 male patients (66%). Recipients of early LT vs standard LT were younger (median [interquartile range (IQR)] age, 49.7 [39.0-54.2] years vs 54.6 [48.7-60.0] years; P < .001) and had a higher median (IQR) Model for End-stage Liver Disease score at listing (35.0 [29.0-39.0] vs 20.0 [13.0-26.0]; P < .001). Both recipients of early LT and standard LT had similar 1-year patient survival (94.1% [95% CI, 86.3%-97.5%] vs 95.9% [95% CI, 87.8%-98.7%]; P = .60), allograft survival (92.7% [95% CI, 84.4%-96.7%] vs 90.5% [95% CI, 81.0%-95.3%]; P = .42), relapse-free survival (80.4% [95% CI, 69.1%-88.0%] vs 83.5% [95% CI, 72.2%-90.6%]; P = .41), and hazardous relapse-free survival (85.8% [95% CI, 75.1%-92.2%] vs 89.6% [95% CI, 79.5%-94.9%]; P = .41). Conclusions and Relevance: Adherence to the 6-month rule was not associated with superior patient survival, allograft survival, or relapse-free survival among selected patients. This finding suggests that patients with ALD should not be categorically excluded from LT solely on the basis of 6 months of abstinence, but rather alternative selection criteria should be identified that are based on need and posttransplant outcomes.

Protein synthesis inhibitor omacetaxine is effective against hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is the sixth most common and the fourth most deadly cancer worldwide. The development cost of new therapeutics is a major limitation in patient outcomes. Importantly, there is a paucity of preclinical HCC models in which to test new small molecules. Herein, we implemented potentially novel patient-derived organoid (PDO) and patient-derived xenografts (PDX) strategies for high-throughput drug screening. Omacetaxine, an FDA-approved drug for chronic myelogenous leukemia (CML), was found to be a top effective small molecule in HCC PDOs. Next, omacetaxine was tested against a larger cohort of 40 human HCC PDOs. Serial dilution experiments demonstrated that omacetaxine is effective at low (nanomolar) concentrations. Mechanistic studies established that omacetaxine inhibits global protein synthesis, with a disproportionate effect on short-half-life proteins. High-throughput expression screening identified molecular targets for omacetaxine, including key oncogenes, such as PLK1. In conclusion, by using an innovative strategy, we report - for the first time to our knowledge - the effectiveness of omacetaxine in HCC. In addition, we elucidate key mechanisms of omacetaxine action. Finally, we provide a proof-of-principle basis for future studies applying drug screening PDOs sequenced with candidate validation in PDX models. Clinical trials could be considered to evaluate omacetaxine in patients with HCC.

Validation of predictive models identifying patients at risk for massive transfusion during liver transplantation and their potential impact on blood bank resource utilization.

BACKGROUND: Intraoperative massive transfusion (MT) is common during liver transplantation (LT). A predictive model of MT has the potential to improve use of blood bank resources. STUDY DESIGN AND METHODS: Development and validation cohorts were identified among deceased-donor LT recipients from 2010 to 2016. A multivariable model of MT generated from the development cohort was validated with the validation cohort and refined using both cohorts. The combined cohort also validated the previously reported McCluskey risk index (McRI). A simple modified risk index (ModRI) was then created from the combined cohort. Finally, a method to translate model predictions to a population-specific blood allocation strategy was described and demonstrated for the study population. RESULTS: Of the 403 patients, 60 (29.6%) in the development and 51 (25.5%) in the validation cohort met the definition for MT. The ModRI, derived from variables incorporated into multivariable model, ranged from 0 to 5, where 1 point each was assigned for hemoglobin level of less than 10 g/dL, platelet count of less than 100 × 109 /dL, thromboelastography R interval of more than 6 minutes, simultaneous liver and kidney transplant and retransplantation, and a ModRI of more than 2 defined recipients at risk for MT. The multivariable model, McRI, and ModRI demonstrated good discrimination (c statistic [95% CI], 0.77 [0.70-0.84]; 0.69 [0.62-0.76]; and 0.72 [0.65-0.79], respectively, after correction for optimism). For blood allocation of 6 or 15 units of red blood cells (RBCs) based on risk of MT, the ModRI would prevent unnecessary crossmatching of 300 units of RBCs/100 transplants. CONCLUSIONS: Risk indices of MT in LT can be effective for risk stratification and reducing unnecessary blood bank resource utilization.

Major Improvement in Wound Healing Through Pharmacologic Mobilization of Stem Cells in Severely Diabetic Rats.

Current therapeutic strategies for diabetic foot ulcer (DFU) have focused on developing topical healing agents, but few agents have controlled prospective data to support their effectiveness in promoting wound healing. We tested a stem cell mobilizing therapy for DFU using a combination of AMD3100 and low-dose FK506 (tacrolimus) (AF) in streptozocin-induced type 1 diabetic (T1DM) rats and type 2 diabetic Goto-Kakizaki (GK) rats that had developed peripheral artery disease and neuropathy. Here, we show that the time for healing back wounds in T1DM rats was reduced from 27 to 19 days, and the foot wound healing time was reduced from 25 to 20 days by treatment with AF (subcutaneously, every other day). Similarly, in GK rats treated with AF, the healing time on back wounds was reduced from 26 to 21 days. Further, this shortened healing time was accompanied by reduced scar and by regeneration of hair follicles. We found that AF therapy mobilized and recruited bone marrow-derived CD133+ and CD34+ endothelial progenitor cells and Ym1/2+ M2 macrophages into the wound sites, associated with enhanced capillary and hair follicle neogenesis. Moreover, AF therapy improved microcirculation in diabetic and neuropathic feet in GK rats. This study provides a novel systemic therapy for healing DFU.

What's the score? A comparison of deceased donor kidney scoring systems and correlation with graft outcome.

BACKGROUND: A number of deceased donor kidney scoring systems have been developed to predict post-transplant graft failure. However, studies comparing the predictive ability of these scoring systems to each other are lacking. METHODS: We used single-center histopathologic and UNOS data from 140 marginal deceased donor kidneys and transplant recipients to compare the predictive accuracy of the Maryland Aggregate Pathology Index (MAPI), Kidney Donor Risk Index (KDRI), Remuzzi, and Nyberg scoring systems for 2-year graft survival using time-dependent receiver operating curves and Kaplan-Meier analysis. RESULTS: MAPI had the highest predictive accuracy (area under curve [AUC] = 0.81) compared to KDRI (AUC = 0.45), Remuzzi (AUC = 0.59), and Nyberg (AUC = 0.63) for 2-year graft survival. Furthermore, when analyzing each score according to its pre-defined risk strata, MAPI was the only scoring system for which 2-year graft survival was significantly different across strata (84.3% for low risk, 56.5% for intermediate risk, and 50% for high risk, P < .001). Additionally, MAPI was the only risk score significantly associated with 2-year graft survival (hazard ratio per point: 1.12, 95% confidence interval [CI]: 1.01-1.23, P = .03). CONCLUSIONS: In a single-center cohort of biopsied marginal kidneys used for transplantation, MAPI had the best predictive ability of these four scoring systems. When biopsy data are available for kidneys considered for transplantation, the MAPI score may provide additional information that could be used to better identify kidneys likely to have longer graft survival.

Hepatitis C-positive donor liver transplantation for hepatitis C seronegative recipients.

BACKGROUND: The opioid crisis has led to an increase in hepatitis C virus-positive donors in the past decade. Whereas historically hepatitis C seropositive organs were routinely discarded, the advent of direct-acting antiviral agents has notably expanded the utilization of organs from donors with hepatitis C. There has been growing experience with liver transplantation (LT) from hepatitis C seropositive donors to hepatitis C seropositive recipients. However, data remain limited on LT from hepatitis C seropositive or hepatitis C ribonucleic acid positive donors to hepatitis C seronegative recipients. METHODS: We performed a retrospective study of 26 hepatitis C seronegative recipients who received hepatitis C seropositive donor livers followed by preemptive antiviral therapy with direct-acting antiviral treatment at the Johns Hopkins Hospital Comprehensive Transplant Center from January 1, 2017, to August 31, 2019. RESULTS: Twenty-five of the 26 recipients are alive with proper graft function; 20 of them received livers from hepatitis C nucleic acid testing positive donors. All 12 recipients who completed their direct-acting antiviral courses and have reached sufficient follow-up for sustained virologic response have achieved sustained virologic response. Nine of our recipients have either completed direct-acting antiviral treatment without sufficient follow-up time for sustained virologic response or are undergoing direct-acting antiviral treatment. One patient is awaiting antiviral treatment initiation pending insurance approval. Of note, 11 of 12 patients with sustained virologic response received a hepatitis C nucleic acid testing positive donor liver. CONCLUSION: Hepatitis C seronegative patients who receive a hepatitis C seropositive or hepatitis C nucleic acid testing positive liver allograft can enjoy good short-term outcomes with hepatitis C cure following direct-acting antiviral treatment.

Orthotopic Rat Kidney Transplantation: A Novel and Simplified Surgical Approach.

Kidney transplantation offers increased survival rates and improved quality of life for patients with end-stage renal disease, as compared to any type of renal replacement therapy. Over the past few decades, the rat kidney transplantation model has been used to study the immunological phenomena of rejection and tolerance. This model has become an indispensable tool to test new immunomodulatory pharmaceuticals and regimens prior to proceeding with expensive preclinical large animal studies. This protocol provides a detailed overview of how to reliably perform orthotopic kidney transplantation in rats. This protocol includes three distinctive steps that increase the probability of success: perfusion of the donor kidney by flushing through the portal vein and the use of a cuff system to anastomose the renal veins and ureters, thereby decreasing cold and warm ischemia times. Using this technique, we have achieved survival rates beyond 6 months with normal serum creatinine in animals with syngeneic or tolerant kidney transplants. Depending on the aim of the study, this model can be modified by pre- or posttransplant treatments to study the acute, chronic, cellular, or antibody-mediated rejection. It is a reproducible, reliable, and cost-effective animal model to study different aspects of kidney transplantation.

Stem Cell Mobilization Is Lifesaving in a Large Animal Preclinical Model of Acute Liver Failure.

INTRODUCTION: Acute liver failure (ALF) affects 2000 Americans each year with no treatment options other than liver transplantation. We showed previously that mobilization of endogenous stem cells is protective against ALF in rodents. The objective of this study was to assess whether stem cell mobilizing drugs are lifesaving in a large animal preclinical model of ALF, to assess readiness for a clinical trial. METHODS: Male Yorkshire pigs (14-18 kg) were divided into 2 groups, control (n = 6) and treatment (n = 6). All pigs received an intravenous bolus of the hepatotoxin D-galactosamine (0.5 g/kg) via central line and were followed up until death or day 28. Treated animals received simultaneous intramuscular injection of plerixafor (1 mg/kg) and G-CSF (2 µg/kg) at baseline, 24 and 48 hours after toxin infusion to mobilize endogenous stem cells, as previously described. Control animals received saline. RESULTS: All control animals (6/6) succumbed to liver failure within 91 hours, confirmed by clinical, biochemical, and histopathological evidence of ALF. In the treatment group (5/6) animals survived indefinitely despite comparable biochemical changes during the first 48 hours (P = 0.003). White blood cell count increased by a mean of 4× in the treated group at the peak of mobilization (P = 0.0004). CONCLUSIONS: Stem cell mobilizing drugs were lifesaving in a preclinical large animal model of ALF. Since no therapeutic options other than liver transplantation are currently available for critically ill patients with ALF, a multicenter clinical trial is warranted.

Removal of Noninfected Arteriovenous Fistulae after Kidney Transplantation is a Safe and Beneficial Management Strategy for Unused Dialysis Access.

BACKGROUND: Renal transplant recipients often maintain their hemodialysis access in the event of future allograft failure. Patients may develop complications related to the unused dialysis access, and it also limits vein availability for phlebotomy. Accordingly, a change in the current paradigm may be warranted. This study evaluates the indications for, and safety of, arteriovenous fistula (AVF) removal in patients after successful renal transplantation. METHODS: All patients who underwent AVF excision at a single institution from 2006 to 2016 were retrospectively reviewed. Within that cohort, those undergoing removal after renal transplantation were included for analysis. Baseline patient characteristics, including renal function at the time of removal, reason for excision, and age of the AVF, were examined. The primary outcome was the need for dialysis after AVF removal. RESULTS: A total of 114 patients, of which 36 (31.6%) were recipients of renal transplants, underwent fistula removal during the study period. Within the transplant cohort, the median fistula age at the time of excision was 1,903 days (interquartile range: 556-3,394 days). The most common indications for excision included aneurysmal degeneration (n = 9, 25%), pain (n = 6, 16.7%), upper extremity steal syndrome (n = 5, 13.9%), thrombosis (n = 5, 13.9%), high cardiac output heart failure (n = 4, 11%), and extremity swelling secondary to venous hypertension (n = 2, 5.6%). Most patients (30, 83.3%) had intact graft function. Average creatinine and eGFR at the time of excision in these patients were 1.6 mg/dL and 52.3 mL/min/m2, respectively. Two of these 30 patients (6.7%), who had creatinine values of 2.0 and 9.7 mg/dL, went on to require dialysis following excision. The remaining 28 have maintained normal renal function with improvement in their preoperative symptomatology. Two patients (5.6%) experienced postoperative complications-a hematoma requiring evacuation and a superficial wound infection requiring oral antibiotics. CONCLUSIONS: Removal of symptomatic, unused AVFs can be performed safely in renal transplant recipients. Considering the morbidity associated with large AVFs (including high output cardiac failure), the current paradigm of maintaining asymptomatic hemodialysis access in patients with normally functioning renal transplants should be reconsidered.

Direct-Acting Antiviral Prophylaxis in Kidney Transplantation From Hepatitis C Virus-Infected Donors to Noninfected Recipients: An Open-Label Nonrandomized Trial.

Background: Given the high mortality rate for patients with end-stage kidney disease receiving dialysis and the efficacy and safety of hepatitis C virus (HCV) treatments, discarded kidneys from HCV-infected donors may be a neglected public health resource. Objective: To determine the tolerability and feasibility of using direct-acting antivirals (DAAs) as prophylaxis before and after kidney transplantation from HCV-infected donors to non-HCV-infected recipients (that is, HCV D+/R- transplantation). Design: Open-label nonrandomized trial. (ClinicalTrials.gov: NCT02781649). Setting: Single center. Participants: 10 HCV D+/R- kidney transplant candidates older than 50 years with no available living donors. Intervention: Transplantation of kidneys from deceased donors aged 13 to 50 years with positive HCV RNA and HCV antibody test results. All recipients received a dose of grazoprevir (GZR), 100 mg, and elbasvir (EBR), 50 mg, immediately before transplantation. Recipients of kidneys from donors with genotype 1 infection continued receiving GZR-EBR for 12 weeks after transplantation; those receiving organs from donors with genotype 2 or 3 infection had sofosbuvir, 400 mg, added to GZR-EBR for 12 weeks of triple therapy. Measurements: The primary safety outcome was the incidence of adverse events related to GZR-EBR treatment. The primary efficacy outcome was the proportion of recipients with an HCV RNA level below the lower limit of quantification 12 weeks after prophylaxis. Results: Among 10 HCV D+/R- transplant recipients, no treatment-related adverse events occurred, and HCV RNA was not detected in any recipient 12 weeks after treatment. Limitation: Nonrandomized study design and a small number of patients. Conclusion: Pre- and posttransplantation HCV treatment was safe and prevented chronic HCV infection in HCV D+/R- kidney transplant recipients. If confirmed in larger studies, this strategy should markedly expand organ options and reduce mortality for kidney transplant candidates without HCV infection. Primary Funding Source: Merck Sharp & Dohme.