Wound Healing: A Cellular Perspective.

Wound healing is one of the most complex processes in the human body. It involves the spatial and temporal synchronization of a variety of cell types with distinct roles in the phases of hemostasis, inflammation, growth, re-epithelialization, and remodeling. With the evolution of single cell technologies, it has been possible to uncover phenotypic and functional heterogeneity within several of these cell types. There have also been discoveries of rare, stem cell subsets within the skin, which are unipotent in the uninjured state, but become multipotent following skin injury. Unraveling the roles of each of these cell types and their interactions with each other is important in understanding the mechanisms of normal wound closure. Changes in the microenvironment including alterations in mechanical forces, oxygen levels, chemokines, extracellular matrix and growth factor synthesis directly impact cellular recruitment and activation, leading to impaired states of wound healing. Single cell technologies can be used to decipher these cellular alterations in diseased states such as in chronic wounds and hypertrophic scarring so that effective therapeutic solutions for healing wounds can be developed.

Direct cardiac reprogramming: A new technology for cardiac repair.

Cardiovascular disease is one of the leading causes of morbidity and mortality worldwide, with myocardial infarctions being amongst the deadliest manifestations. Reduced blood flow to the heart can result in the death of cardiac tissue, leaving affected patients susceptible to further complications and recurrent disease. Further, contemporary management typically involves a pharmacopeia to manage the metabolic conditions contributing to atherosclerotic and hypertensive heart disease, rather than regeneration of the damaged myocardium. With modern healthcare extending lifespan, a larger demographic will be at risk for heart disease, driving the need for novel therapeutics that surpass those currently available in efficacy. Transdifferentiation and cellular reprogramming have been looked to as potential methods for the treatment of diseases throughout the body. Specifically targeting the fibrotic cells in cardiac scar tissue as a source to be reprogrammed into induced cardiomyocytes remains an appealing option. This review aims to highlight the history of and advances in cardiac reprogramming and describe its translational potential as a treatment for cardiovascular disease.

The effects of COVID-19 on pediatric and adult solid organ transplant recipients and the emergence of telehealth.

BACKGROUND: The SARS-CoV-2 pandemic and corresponding acute respiratory syndrome have affected all populations and led to millions of deaths worldwide. The pandemic disproportionately affected immunocompromised and immunosuppressed adult patients who had received solid organ transplants (SOTs). With the onset of the pandemic, transplant societies across the world recommended reducing SOT activities to avoid exposing immunosuppressed recipients. Due to the risk of COVID-19-related outcomes, SOT providers adapted the way they deliver care to their patients, leading to a reliance on telehealth. Telehealth has helped organ transplant programs continue treatment regimens while protecting patients and physicians from COVID-19 transmission. This review highlights the adverse effects of COVID-19 on transplant activities and summarizes the increased role of telehealth in the management of solid organ transplant recipients (SOTRs) in both pediatric and adult populations. METHODS: A comprehensive systematic review and meta-analysis were conducted to accentuate the outcomes of COVID-19 and analyze the efficacy of telehealth on transplant activities. This in-depth examination summarizes extensive data on the clinical detriments of COVID-19 in transplant recipients, advantages, disadvantages, patient/physician perspectives, and effectiveness in transplant treatment plans via telehealth. RESULTS: COVID-19 has caused an increase in mortality, morbidity, hospitalization, and ICU admission in SOTRs. Telehealth efficacy and benefits to both patients and physicians have increasingly been reported. CONCLUSIONS: Developing effective systems of telehealth delivery has become a top priority for healthcare providers during the COVID-19 pandemic. Further research is necessary to validate the effectiveness of telehealth in other settings.

Impact of the donor hepatectomy time on short-term outcomes in liver transplantation using donation after circulatory death: A review of the US national registry.

BACKGROUND: During the donor hepatectomy time (dHT), defined as the time from the start of cold perfusion to the end of the hepatectomy, liver grafts have a suboptimal temperature. The aim of this study was to analyze the impact of prolonged dHT on outcomes in donation after circulatory death (DCD) liver transplantation (LT). METHODS: Using the US national registry data between 2012 and 2020, DCD LT patients were separated into two groups based on their dHT: standard dHT (< 42 min) and prolonged dHT (≥42 min). RESULTS: There were 3810 DCD LTs during the study period. Median dHT was 32 min (interquartile range 25-41 min). Kaplan-Meier graft survival curves demonstrated inferior outcomes in the prolonged dHT group at 1-year after DCD LT compared to those in the standard dHT group (85.3% vs 89.9%; P < .01). Multivariate Cox proportional hazards models for 1-year graft survival identified that prolonged dHT [hazard ratio (HR) 1.46, 95% confidence interval (CI) 1.19 - 1.79], recipient age ≥ 64 years (HR 1.40, 95% CI 1.14 - 1.72), and MELD score ≥ 24 (HR 1.43, 95% CI 1.16 - 1.76) were significant predictors of 1-year graft loss. Spline analysis shows that the dHT effects on the risk for 1-year graft loss with an increase in the slope after median dHT of 32 min. CONCLUSION: Prolonged dHTs significantly reduced graft and patient survival after DCD LT. Because dHT is a modifiable factor, donor surgeons should take on cases with caution by setting the dHT target of < 32 min.

Outcomes after liver transplantation in MPV17 deficiency (Navajo neurohepatopathy): A single-center case series.

BACKGROUND: MPV17-related mitochondrial DNA maintenance defect (MPV17 deficiency) is a rare, autosomal recessive mitochondrial DNA depletion syndrome with a high mortality rate in infancy and early childhood due to progression to liver failure. Liver transplantation for children with MPV17 deficiency has been considered controversial due to uncertainty about the potential progression of extrahepatic manifestations following liver transplantation. METHODS: We describe our institution's experience for two infants diagnosed with infantile MPV17 deficiency who presented in acute on chronic liver failure, but with normal development and normal neurological status who successfully underwent liver transplantation. RESULTS: Both patients underwent successful liver transplantation with normal development and neurological status at 3 years and 16 months post-transplant, respectively. CONCLUSIONS: In this rare disease population, we describe two infants with MPV17 deficiency who underwent liver transplantation for acute on chronic liver failure who continue to have normal development, without progression of neurological disease. MPV17 deficiency should not be considered a contraindication to liver transplantation.

Mortality Trends in Chronic Liver Disease and Cirrhosis in the United States, Before and During COVID-19 Pandemic.

Chronic liver disease (CLD) and cirrhosis accounts for approximately 2 million deaths annually worldwide. CLD and cirrhosis-related mortality has increased steadily in the United States.1,2 With the global pandemic of coronavirus disease 2019 (COVID-19), patients with CLD and cirrhosis represent a vulnerable population at higher risk for complications and mortality.3,4 Although high mortality from COVID-19 among patients with CLD and cirrhosis have been reported,5 national trends in mortality related to CLD and cirrhosis before and during the COVID-19 pandemic have not been assessed. This study estimated the temporal quarterly trends in CLD and cirrhosis-related mortality in the United States from 2017 Q1 to 2020 Q3 using provisional data releases from the National Vital Statistics System.6,7.

Trends in the Mortality of Biliary Tract Cancers Based on Their Anatomical Site in the United States From 2009 to 2018.

INTRODUCTION: Recent trends in the incidence and mortality of biliary tract cancers are unknown. We estimated the trends in biliary tract cancers-related incidence and mortality stratified by anatomical site, age, sex, and race/ethnicity in the US adults. METHODS: We performed a population-based trend analysis using the US national incidence (2009-2017) and mortality records (2009-2018). We identified age-standardized incidence and mortality from intrahepatic cholangiocarcinoma (ICC), extrahepatic cholangiocarcinoma, gallbladder cancer, and ampulla of Vater cancer using appropriate ICD-10 code. Temporal mortality was calculated by joinpoint trend analysis with estimates of annual percentage change (APC) described as each trend segment. RESULTS: The incidence rates of ICC increased linearly (APC 8.9%, 95% confidence interval [CI] 7.8%-10.0%) while gallbladder cancer-related incidence rates remained stable early and decreased significantly later in the study (APC -2.8%, 95% CI -5.5% to -0.0% [2014-2017]). Age-standardized mortality from biliary tract cancers steadily increased with an annual increase of 2.0% (95% CI 1.6%-2.3%). Although there was a linear increase in the ICC-related mortality (APC 3.5%, 95% CI 3.1%-3.8%), extrahepatic cholangiocarcinoma-related mortality tended to remain stable earlier and increased later (APC 7.0%, 95% CI 4.6%-9.5% [2013-2018]). By contrast, gallbladder cancer-related mortality steadily decreased over 10 years (APC -1.6%, 95% CI -2.1% to -1.1%). Significant differences in mortality and changes in trends over time were observed in non-Hispanic blacks, Hispanics, and non-Hispanic Asians. DISCUSSION: In this analysis of nationally representative data, changing mortality trends in various biliary tract cancers was noted with a disproportionately higher burden of fatality in minorities.

Standardization of post-operative antimicrobials reduced exposure while maintaining good outcomes in pediatric liver transplant recipients.

Infections following orthotopic liver transplant (OLT) result in significant morbidity and mortality, warranting careful consideration of risks associated with antibiotic overuse and benefits of infection prevention. In the absence of specific guidelines for antimicrobial prophylaxis in pediatric OLT, we developed a standardized approach to post-operative (post-op) antimicrobial therapy including 48 hours of antibiotics, no vancomycin for post-op fever within the first 48 hours, and caspofungin only for certain situations. The goal was to reduce antimicrobial utilization and adverse outcomes associated with longer duration of and broader treatment while maintaining good outcomes. The impact of this standardization on antimicrobial utilization and clinical outcomes at the largest pediatric liver transplant center in the United States is described. All individuals receiving an OLT from 1/1/17-9/30/17 (N = 38) and 3/14/18-12/13/18 (N = 27) were included in the pre-intervention (PreI) and post-intervention (PostI) groups, respectively. The intervention resulted in a significant reduction in individuals receiving post-op broad-spectrum gram-negative antibiotics for >48 hours (76% PreI vs 44% PostI OLT recipients, P = .01) and post-op vancomycin use (50% PreI, vs 7.4% PostI, P < .001). There were no statistically significant differences between groups for post-op fever, positive pre-/post-operative cultures, receipt of massive transfusion, or hospital length of stay. In conclusion, following the implementation of a standardized approach to post-op prophylaxis, antimicrobial exposure was significantly reduced without affecting OLT recipient outcomes.

Macrophage Subpopulation Dynamics Shift following Intravenous Infusion of Mesenchymal Stromal Cells.

Intravenous infusion of mesenchymal stromal cells (MSCs) is thought to be a viable treatment for numerous disorders. Although the intrinsic immunosuppressive ability of MSCs has been credited for this therapeutic effect, their exact impact on endogenous tissue-resident cells following delivery has not been clearly characterized. Moreover, multiple studies have reported pulmonary sequestration of MSCs upon intravenous delivery. Despite substantial efforts to improve MSC homing, it remains unclear whether MSC migration to the site of injury is necessary to achieve a therapeutic effect. Using a murine excisional wound healing model, we offer an explanation of how sequestered MSCs improve healing through their systemic impact on macrophage subpopulations. We demonstrate that infusion of MSCs leads to pulmonary entrapment followed by rapid clearance, but also significantly accelerates wound closure. Using single-cell RNA sequencing of the wound, we show that following MSC delivery, innate immune cells, particularly macrophages, exhibit distinctive transcriptional changes. We identify the appearance of a pro-angiogenic CD9+ macrophage subpopulation, whose induction is mediated by several proteins secreted by MSCs, including COL6A1, PRG4, and TGFB3. Our findings suggest that MSCs do not need to act locally to induce broad changes in the immune system and ultimately treat disease.

Eliminating international normalized ratio threshold for transfusion in pediatric patients with acute liver failure.

INTRODUCTION: Transfusion protocols are not well-studied for pediatric patients with acute liver failure (ALF). This study evaluates the utility of an international normalized ratio (INR)-based transfusion threshold for these patients. METHODS: Forty-four ALF pediatric patients from 2009 to 2018 were reviewed and divided into two groups: (a) a threshold group including patients between 2009 and 2015 who were transfused for an INR above 3.0, per institutional policy (n = 30), and (b) a post-threshold group including patients after 2015 through 2018 who were transfused based on clinical judgment (n = 14). Preoperative INRs, preoperative transfusions, intraoperative transfusions, early reoperation, renal function, graft function and deaths were compared. RESULTS: Liver failure severity was similar between threshold and post-threshold groups. Threshold patients had a lower average INR prior to transplantation, 2.8 (range 1.8-3.8) vs 4.4 (range 2.1-9.0), respectively (P = .01). Twenty-six threshold patients (87%) received preoperative FFP compared with seven post-threshold patients (50%, P = .0088). Two threshold patients (7%) received preoperative cryoprecipitate compared with five post-threshold patients (36%, P = .014). The incidence of pre-transplant bleeding, operative transfusions, and 1-year patient and graft survival did not differ significantly. CONCLUSION: Clinical judgment vs an INR-based threshold for transfusions did not increase perioperative complications in children with ALF.

Cryopreserved human skin allografts promote angiogenesis and dermal regeneration in a murine model.

Cryopreserved human skin allografts (CHSAs) are used for the coverage of major burns when donor sites for autografts are insufficiently available and have clinically shown beneficial effects on chronic non-healing wounds. However, the biologic mechanisms behind the regenerative properties of CHSA remain elusive. Furthermore, the impact of cryopreservation on the immunogenicity of CHSA has not been thoroughly investigated and raised concerns with regard to their clinical application. To investigate the importance and fate of living cells, we compared cryopreserved CHSA with human acellular dermal matrix (ADM) grafts in which living cells had been removed by chemical processing. Both grafts were subcutaneously implanted into C57BL/6 mice and explanted after 1, 3, 7, and 28 days (n = 5 per group). A sham surgery where no graft was implanted served as a control. Transmission electron microscopy (TEM) and flow cytometry were used to characterise the ultrastructure and cells within CHSA before implantation. Immunofluorescent staining of tissue sections was used to determine the immune reaction against the implanted grafts, the rate of apoptotic cells, and vascularisation as well as collagen content of the overlaying murine dermis. Digital quantification of collagen fibre alignment on tissue sections was used to quantify the degree of fibrosis within the murine dermis. A substantial population of live human cells with intact organelles was identified in CHSA prior to implantation. Subcutaneous pockets with implanted xenografts or ADMs healed without clinically apparent rejection and with a similar cellular immune response. CHSA implantation largely preserved the cellularity of the overlying murine dermis, whereas ADM was associated with a significantly higher rate of cellular apoptosis, identified by cleaved caspase-3 staining, and a stronger dendritic cell infiltration of the murine dermis. CHSA was found to induce a local angiogenic response, leading to significantly more vascularisation of the murine dermis compared with ADM and sham surgery on day 7. By day 28, aggregate collagen-1 content within the murine dermis was greater following CHSA implantation compared with ADM. Collagen fibre alignment of the murine dermis, correlating with the degree of fibrosis, was significantly greater in the ADM group, whereas CHSA maintained the characteristic basket weave pattern of the native murine dermis. Our data indicate that CHSAs promote angiogenesis and collagen-1 production without eliciting a significant fibrotic response in a xenograft model. These findings may provide insight into the beneficial effects clinically observed after treatment of chronic wounds and burns with CHSA.

Deferoxamine can prevent pressure ulcers and accelerate healing in aged mice.

Chronic wounds are a significant medical and economic problem worldwide. Individuals over the age of 65 are particularly vulnerable to pressure ulcers and impaired wound healing. With this demographic growing rapidly, there is a need for effective treatments. We have previously demonstrated that defective hypoxia signaling through destabilization of the master hypoxia-inducible factor 1α (HIF-1α) underlies impairments in both aging and diabetic wound healing. To stabilize HIF-1α, we developed a transdermal delivery system of the Food and Drug Administration-approved small molecule deferoxamine (DFO) and found that transdermal DFO could both prevent and treat ulcers in diabetic mice. Here, we demonstrate that transdermal DFO can similarly prevent pressure ulcers and normalize aged wound healing. Enhanced wound healing by DFO is brought about by stabilization of HIF-1α and improvements in neovascularization. Transdermal DFO can be rapidly translated into the clinic and may represent a new approach to prevent and treat pressure ulcers in aged patients.

Treatment of methylmalonic acidemia by liver or combined liver-kidney transplantation.

OBJECTIVE: To assess biochemical, surgical, and long-term outcomes of liver (LT) or liver-kidney transplantation (LKT) for severe, early-onset methylmalonic acidemia/acid (MMA). STUDY DESIGN: A retrospective chart review (December 1997 to May 2012) of patients with MMA who underwent LT or LKT at Lucile Packard Children's Hospital at Stanford. RESULTS: Fourteen patients underwent LT (n = 6) or LKT (n = 8) at mean age 8.2 years (range 0.8-20.7). Eleven (79%) were diagnosed during the neonatal period, including 6 by newborn screening. All underwent deceased donor transplantation; 12 (86%) received a whole liver graft. Postoperative survival was 100%. At a mean follow-up of 3.25 ± 4.2 years, patient survival was 100%, liver allograft survival 93%, and kidney allograft survival 100%. One patient underwent liver re-transplantation because of hepatic artery thrombosis. After transplantation, there were no episodes of hyperammonemia, acidosis, or metabolic decompensation. The mean serum MMA at the time of transplantation was 1648 ± 1492 µmol/L (normal <0.3, range 99-4420). By 3 days, post-transplantation levels fell on average by 87% (mean 210 ± 154 µmol/L), and at 4 months, they were 83% below pre-transplantation levels (mean 305 ± 108 µmol/L). Developmental delay was present in 12 patients (86%) before transplantation. All patients maintained neurodevelopmental abilities or exhibited improvements in motor skills, learning abilities, and social functioning. CONCLUSIONS: LT or LKT for MMA eradicates episodes of hyperammonemia, results in excellent long-term survival, and suggests stabilization of neurocognitive development. Long-term follow-up is underway to evaluate whether patients who undergo early LT need kidney transplantation later in life.

HCV infection is associated with lower survival in simultaneous liver kidney transplant recipients in the United States.

BACKGROUND: The frequency of simultaneous liver kidney transplantation (SLKT) has been increasing over the past decade. Hepatitis C virus (HCV) infection is the most common indication for liver transplantation in the United States. Given the rising prevalence of HCV-related SLKT, it is important to understand the impact of HCV in this patient population. METHODS: We conducted a retrospective cohort study using data from the United Network for Organ Sharing registry to assess adult patients undergoing SLKT in the United States from 2003 to 2012. Patient survival following SLKT was assessed using Kaplan-Meier methods and multivariate Cox proportional hazards models. RESULTS: Patients infected with non-HCV have significantly lower survival following SLKT compared to non-HCV patients at three (three-yr survival: 71.0% vs. 78.9%, p < 0.01) and five yr (five-yr survival: 61.4% vs. 72.5%, p < 0.01). The results of multivariate regression analyses demonstrated that patients infected with HCV had significantly lower survival following SLKT than patients with non-HCV disease (HR 1.41, 95% CI, 1.19-1.67, p < 0.001). In addition, lower post-SLKT survival was noted among patients with diabetes (HR 1.34, 95% CI, 1.13-1.58, p < 0.001) and hepatocellular carcinoma (HR 1.60, 95% CI, 1.17-2.18, p < 0.01). CONCLUSIONS: Hepatitis C infection is associated with lower patient survival following SLKT.

Recurrent hepatocellular carcinoma and poorer overall survival in patients undergoing left-sided compared with right-sided partial hepatectomy.

GOALS: We aimed to determine the incidence and predictors of recurrent hepatocellular carcinoma (HCC) after partial hepatectomy. BACKGROUND: Liver transplantation is the preferred treatment for selected patients with HCC, but access to donor organs is limited. Partial hepatectomy is another accepted treatment option; however, postoperative recurrence is frequently observed. METHODS: This is a retrospective cohort study of 107 consecutive patients who underwent partial hepatectomy for HCC between January 1993 and February 2011 at a US University Medical Center. Study endpoints were recurrent HCC, death, loss to follow-up, or last visit without HCC. RESULTS: The study cohort was 78% male with a median age of 61 years and 59% Asians. A total of 50 patients developed recurrent HCC (46.7%) after a median follow-up of 12 (1 to 69) months postresection. Recurrent HCC was significantly higher in patients with left-sided resection (41% at year 1, 54% at year 2, 62% at year 3, 81% at year 4, and 90% at year 5) compared with right-sided resection (18% at year 1, 34% at year 2, 36% at year 3, 44% at year 4, and 72% at year 5). In multivariate Cox proportional hazards model also inclusive of anatomic resection and TNM stage 3/4, left-sided resection was significantly associated with increased HCC recurrence (hazard ratio, 2.13; P=0.02; 95% confidence interval, 1.08-4.2) compared with right-sided resection. CONCLUSIONS: HCC recurrence rate is higher among those undergoing left-sided resection: 54% at year 2 and 81% at year 4. Liver transplantation should be considered in patients who are at high risk for recurrence.

Improved survival outcomes in patients with non-alcoholic steatohepatitis and alcoholic liver disease following liver transplantation: an analysis of 2002-2012 United Network for Organ Sharing data.

There is an increasing trend of patients with hepatocellular carcinoma (HCC) and non-alcoholic fatty liver disease undergoing liver transplantation in the US. Our study utilized data from the 2002 to 2012 United Network for Organ Sharing registry to evaluate model for end-stage liver disease era trends in US liver transplantations focused on patients with non-alcoholic steatohepatitis (NASH), hepatitis C (HCV), alcoholic liver disease (ALD), and HCC. Survival outcomes were stratified by liver disease etiology and compared across time periods using Kaplan-Meier and Cox proportional hazards models. Patients with NASH were more likely to be women, had higher body mass index (BMI), and had higher prevalence of diabetes and cardiac disease. However, overall long-term survival was significantly higher in patients with NASH and ALD (p < 0.001). Compared to HCV, patients with NASH had significantly higher post-transplantation survival (HR 0.69, 95% CI 0.63-0.77), and lower risk of graft failure (HR 0.76, 95% CI 0.69-0.83). Despite having higher BMI and higher prevalence of diabetes and cardiac disease, patients with NASH had better post-liver transplantation survival compared to patients with HCV or HCC. Patients with ALD also had superior survival outcomes. However, these survival differences were limited to patients without HCC that underwent liver transplantation.

Primary surgical resection versus liver transplantation for transplant-eligible hepatocellular carcinoma patients.

BACKGROUND: Hepatocellular carcinoma (HCC) is a leading cause of mortality worldwide. Existing studies comparing outcomes after liver transplantation (LT) versus surgical resection among transplant-eligible patients are conflicting. AIM: The purpose of this study was to compare long-term survival between consecutive transplant-eligible HCC patients treated with resection versus LT. METHODS: The present retrospective matched case cohort study compares long-term survival outcomes between consecutive transplant-eligible HCC patients treated with resection versus LT using intention-to-treat (ITT) and as-treated models. Resection patients were matched to LT patients by age, sex, and etiology of HCC in a 1:2 ratio. RESULTS: The study included 171 patients (57 resection and 114 LT). Resection patients had greater post-treatment tumor recurrence (43.9 vs. 12.9 %, p < 0.001) compared to LT patients. In the as-treated model of the pre-model for end stage liver disease (MELD) era, LT patients had significantly better 5-year survival compared to resection patients (100 vs. 69.5 %, p = 0.04), but no difference was seen in the ITT model. In the multivariate Cox proportional hazards model, inclusive of age, sex, ethnicity, tumor stage, and MELD era (pre-MELD vs. post-MELD), treatment with resection was an independent predictor of poorer survival (HR 2.72; 95 % CI, 1.08-6.86). CONCLUSION: Transplant-eligible HCC patients who received LT had significantly better survival than those treated with resection, suggesting that patients who can successfully remain on LT listing and actually undergo LT have better outcomes.

Pediatric Combined Heart-liver Transplantation: A Single-center Long-term Experience.

Background: Combined heart liver transplant (CHLT) continues to gain attention as a surgical treatment for patients with end-stage heart and liver disease but remains rare. We present our institutional longitudinal experience with up to 14 y of follow-up, focused on long-term outcomes in CHLT recipients. Methods: We conducted a single-institutional, retrospective review from January 1, 2010, to December 31, 2023, including 7 patients ages 7-17 y who underwent CHLT. Results: Most patients were surgically palliated via Fontan procedure pretransplant (n = 6), and all had evidence of advanced fibrosis or cirrhosis before transplant. The 30-d mortality was 14.3% (n = 1, multiorgan failure). During the follow-up period, 1 patient developed acute heart rejection which required treatment and 2 developed acute liver rejection. In all cases, rejection was successfully treated. Two patients developed acute heart rejection which did not require treatment (grade 1R). No patients developed chronic or refractory rejection. No patients developed allograft coronary artery vasculopathy. Conclusions: CHLT remains a rarely performed treatment for pediatric patients with end-stage heart and liver disease, but our long-term data suggest that this treatment strategy should be considered more frequently.

Liver transplantation for urea cycle disorders in pediatric patients: a single-center experience.

LT has emerged as a surgical treatment for UCDs. We hypothesize that LT can be safely and broadly utilized in the pediatric population to effectively prevent hyperammonemic crises and potentially improve neurocognitive outcomes. To determine the long-term outcomes of LT for UCDs, charts of children with UCD who underwent LT were retrospectively reviewed at an academic institution between July 2001 and May 2012. A total of 23 patients with UCD underwent LT at a mean age of 3.4 yr. Fifteen (65%) patients received a whole-liver graft, seven patients (30%) received a reduced-size graft, and one patient received a living donor graft. Mean five-yr patient survival was 100%, and allograft survival was 96%. Mean peak blood ammonia (NH(3) ) at presentation was 772 µmol/L (median 500, range 178-2969, normal <30-50). After transplantation, there were no episodes of hyperammonemia. Eleven patients were diagnosed with some degree of developmental delay before transplantation, which remained stable or improved after transplantation. Patients without developmental delay before transplantation maintained their cognitive abilities at long-term follow-up. LT was associated with the eradication of hyperammonemia, removal of dietary restrictions, and potentially improved neurocognitive development. Long-term follow-up is underway to evaluate whether LT at an early age (<1 yr) will attain improved neurodevelopmental outcomes.