Addressing sex-based disparities in liver transplantation

PURPOSE OF REVIEW

Disparities in access to liver transplantation by sex have been well described, disadvantaging women. Understanding the multifactorial causes of these disparities as well as the variety of proposed solutions is critical to improving access to this life-saving intervention for women. This review aims to summarize the current body of evidence on observed sex disparities in liver transplantation and highlight actionable, evidence-based mechanisms by which these disparities can be addressed.

RECENT FINDINGS

Strategies for addressing sex disparities in liver transplantation include increasing organ utilization, changing allocation policy, and leveraging public policies to reduce the incidence of end-stage liver disease. Several other promising interventions are currently being explored.

SUMMARY

In the United States, women face additional barriers to liver transplantation on the basis of sex. Immediate action is necessary to systematically address these inequities.

Prospective clinical trials and novel therapies in the medical management of severe alcohol-associated hepatitis

Content available: Author Interview and Audio Recording.

Naltrexone for alcohol use disorder: Hepatic safety in patients with and without liver disease

Naltrexone is an approved drug for management of alcohol use disorder (AUD), but data in patients with liver disease (LD) are limited. We aimed to evaluate the safety of naltrexone in those with LD. This is a retrospective cohort of adults with and without LD who were prescribed naltrexone for AUD from 2015 to 2019 in a safety-net setting. Naltrexone hepatic safety was determined by liver enzyme changes during and after compared to before naltrexone prescription as well as rates of subsequent hospitalization and death by Kaplan-Meier methods. Factors associated with hospitalization were examined by Cox regression. Of 160 patients prescribed naltrexone for AUD, 100 (63%) had LD and 47 (47%) of those with LD had cirrhosis (47% decompensated). The total cohort, LD, and cirrhosis groups had lower adjusted mean aspartate aminotransferase and alanine aminotransferase levels after versus before naltrexone prescription (p < 0.001). Two-year survival was 97.7% (95% confidence interval [CI], 84.6-99.7), 95.4% (95% CI, 82.8-98.8), 90.8% (95% CI, 73.5-97.0), and 81.3% (95% CI, 41.2-93.8) in those without LD, LD without cirrhosis, cirrhosis, and decompensated cirrhosis groups (p = 0.46), respectively. Alcohol-related 2-year hospitalization rates were 8.2% (95% CI, 2.7-24), 27.7% (95% CI, 16.6-44.0), 40.5% (95% CI, 24.8-61.6), and 41.7% (95% CI, 23.3-66.6) for the groups without LD, LD without cirrhosis, cirrhosis, and decompensated cirrhosis (p = 0.007), respectively. Independent predictors of subsequent hospitalization were LD, (hazard ratio [HR], 3.70; 95% CI, 1.19-11.51; p = 0.02), cirrhosis (HR, 5.16; 95% CI, 1.69-15.75), and shorter duration (≤30 days) of naltrexone prescription (HR, 2.50; 95% CI, 1.l2-5.20; p = 0.01). Conclusion: Naltrexone is safe to use in patients with underlying LD, including those with compensated cirrhosis. Although encouraging, more safety data are needed for those with decompensated cirrhosis.

Contemporary strategies to assess and manage liver donor steatosis: a review

PURPOSE OF REVIEW

Due to a persistent shortage of donor livers, attention has turned toward ways of utilizing marginal grafts, particularly those with steatosis, without incurring inferior outcomes. Here we review the evaluation and utilization of steatotic liver allografts, highlight recently published data, and discuss novel methods of graft rehabilitation.

RECENT FINDINGS

Although severe liver allograft (>60%) steatosis has been associated with inferior graft and recipient outcomes, mild (<30%) steatosis has not. There is ongoing debate regarding safe utilization of grafts with moderate (30-60%) steatosis. Presently, no established protocols for evaluating steatosis in donor candidates or utilizing such grafts exist. Liver biopsy is accepted as the gold standard technique, though noninvasive methods have shown promise in accurately predicting steatosis. More recently, machine perfusion has been shown to enhance ex situ liver function and reduce steatosis, emerging as a potential means of optimizing steatotic grafts prior to transplantation.

SUMMARY

Steatotic liver allografts constitute a large proportion of deceased donor organs. Further work is necessary to define safe upper limits for the acceptable degree of steatosis, develop standardized evaluation protocols, and establish utilization guidelines that prioritize safety. Machine perfusion has shown promise in rehabilitating steatotic grafts and offers the possibility of expanding the deceased donor pool.

Meta-analysis and meta-regression of outcomes for adult living donor liver transplantation versus deceased donor liver transplantation

Prior single center or registry studies have shown that living donor liver transplantation (LDLT) decreases waitlist mortality and offers superior patient survival over deceased donor liver transplantation (DDLT). The aim of this study was to compare outcomes for adult LDLT and DDLT via systematic review. A meta-analysis was conducted to examine patient survival and graft survival, MELD, waiting time, technical complications, and postoperative infections. Out of 8600 abstracts, 19 international studies comparing adult LDLT and DDLT published between 1/2005 and 12/2017 were included. U.S. outcomes were analyzed using registry data. Overall, 4571 LDLT and 66,826 DDLT patients were examined. LDLT was associated with lower mortality at 1, 3, and 5 years posttransplant (5-year HR 0.87 [95% CI 0.81-0.93], p < .0001), similar graft survival, lower MELD at transplant (p < .04), shorter waiting time (p < .0001), and lower risk of rejection (p = .02), with a higher risk of biliary complications (OR 2.14, p < .0001). No differences were observed in rates of hepatic artery thrombosis. In meta-regression analysis, MELD difference was significantly associated with posttransplant survival (R² 0.56, p = .02). In conclusion, LDLT is associated with improved patient survival, less waiting time, and lower MELD at LT, despite posing a higher risk of biliary complications that did not affect survival posttransplant.

Demographic and serological characteristics of Asian Americans with hepatitis B infection diagnosed at community screenings

There is limited information regarding follow-up and hepatitis B serological status of Asian Americans diagnosed with chronic hepatitis B (CHB) through community screening. The aims of this study were to evaluate the prevalence and characterize CHB among Asians living in Los Angeles, assess follow-up of individuals with CHB diagnosed at screening and compare with patients with CHB followed by community gastroenterologists. Between October 2007 and May 2010, 7387 Asians were tested for HBV. HBsAg positive individuals (CHB) underwent additional testing for ALT, HBeAg/anti-HBe and HBV DNA. Patients with CHB were contacted 6 months later to determine whether they received follow-up care. We compared serological patterns of these individuals with CHB to patients with CHB who were seen for the first time (treatment naïve) by community gastroenterologists during the study period. Prevalence of CHB was 5.2%. About 99% patients with CHB were foreign-born, and only 27% could read/write English. 297 (77%) patients with CHB could be reached 6 months after diagnosis; 43% did not receive follow-up care, mostly because of lack of medical insurance. Patients with CHB followed by gastroenterologists were more likely to have insurance (69% vs 26%, P < 0.0001). 90% patients with CHB at screening were HBeAg negative/anti-HBe positive with 62% having inactive disease compared to only 30% of patients seen by gastroenterologists (P < 0.0001). Among CHB participants, 13% met criteria for treatment compared to 51% of patients with CHB (P < 0.0001). Only a small number of CHB screening participants require antiviral therapy. Lack of medical insurance is the main reason for most patients with CHB not seeking follow-up care after screening.

Chlamydia psittaci genotype B in a pigeon (Columba livia) inhabiting a public place in San José, Costa Rica

Human chlamydiosis is a zoonotic disease of avian origin caused by Chlamydia psittaci. The highest infection rates have been detected in parrots (Psittacidae) and pigeons (Columbiformes), the latter most frequently carry the genotypes B and E. These genotypes have been shown to also infect humans. Because pigeons (Columba livia) cohabit with humans in urban areas, C. psittaci present in the dust from dry feces of infected pigeons may be transmitted by inhalation and represent a significant public health problem. Between 2012 and 2013 a total of 120 fecal samples were collected from pigeons at four public places (Plaza de la Cultura, Parque Morazán, Parque Central de Guadalupe, Plaza de las Garantías Sociales) in San José, Costa Rica. A nested polymerase chain reaction (PCR) was used to amplify a region of the outer membrane protein A gene of C. psittaci. Only one sample was positive in PCR and the positive sample was further subjected to sequencing and genotyping. Sequencing identified this sample as C. psittaci genotype B. This study is the first report to show the presence of this organism in pigeons of Costa Rica, and shows that the infected pigeons may represent a significant risk for humans who visit public places that are inhabited by pigeons.

Chlamydia psittaci genotype B in a pigeon (Columba livia) inhabiting a public place in San José, Costa Rica

Human chlamydiosis is a zoonotic disease of avian origin caused by Chlamydia psittaci. The highest infection rates have been detected in parrots (Psittacidae) and pigeons (Columbiformes), the latter most frequently carry the genotypes B and E. These genotypes have been shown to also infect humans. Because pigeons (Columba livia) cohabit with humans in urban areas, C. psittaci present in the dust from dry feces of infected pigeons may be transmitted by inhalation and represent a significant public health problem. Between 2012 and 2013 a total of 120 fecal samples were collected from pigeons at four public places (Plaza de la Cultura, Parque Morazán, Parque Central de Guadalupe, Plaza de las Garantías Sociales) in San José, Costa Rica. A nested polymerase chain reaction (PCR) was used to amplify a region of the outer membrane protein A gene of C. psittaci. Only one sample was positive in PCR and the positive sample was further subjected to sequencing and genotyping. Sequencing identified this sample as C. psittaci genotype B. This study is the first report to show the presence of this organism in pigeons of Costa Rica, and shows that the infected pigeons may represent a significant risk for humans who visit public places that are inhabited by pigeons.

Spin-lattice relaxation enhancement in liquid gallium confined within nanoporous matrices

Nuclear spin relaxation for liquid gallium embedded into nanoporous matrices was found to accelerate remarkably compared to the bulk melt. NMR measurements on two gallium isotopes showed that the dominant mechanism of relaxation was changed from magnetic to quadrupolar and the relation rate depended on the Larmor frequency. The correlation time of electric field gradient fluctuations was estimated using data for quadrupolar relaxation contribution and was found to increase drastically compared to bulk, which corresponded to slowing down mobility in confined liquid gallium.

Effect of Deposition in Deep-Bed Filtration: Determination and Search of Rate Parameters

Particle deposition in deep-bed filters (porous media) is, by nature, an unsteady-state process and the extent of deposition plays an important role in determining filter performance. A general method of establishing the relationship between deposition rate and the extent of deposition from effluent concentration history of filters is presented. The efficacy of the method is examined and its utility demonstrated through its applications to certain experimental data. Copyright 2000 Academic Press.

Electrofiltration of Aqueous Suspensions

Electrofiltration of hydrosols in fixed-bed filters was studied experimentally. The experimental variables examined included media type, electric field strength, and suspension pH values. The extent of particle removal was found to improve with the application of the electric field, and lower pH values favor particle collection. The filtrate quality displayed the transient behavior of increasing particle concentration with time. A simple model which assumes that the filter coefficient decreases linearly with the extent of deposition was developed and found capable of predicting the observed behavior. Copyright 2000 Academic Press.

A model for pulse jet fabric filters

A new model for pulse jet fabric filtration is proposed. In contrast to the earlier model of Ravin and Humphries, which was formulated on the steady state assumption, the present study is aimed at developing a predictive capability for both transient and steady state operations, taking into account the compression effect of filter cakes. The model's relative simplicity allows frequent updating of the model parameter values, thus improving the accuracy of predictions. As a result, the model is particularly useful in developing control algorithms and designing controllers of pulse jet fabric filtration systems.

Particle Deposition under Unfavorable Surface Interactions

Experiments were conducted on particle deposition in granular media (deep bed filters) under the condition of unfavorable surface interactions. The data collected together with those of previous investigators constitute a sufficiently large data base on which correlations were developed to predict the extent of the reduction in particle deposition as a function of relevant operating and system variables. The new correlation equation was found to describe the experimental results reasonably well from the present experimental work or the present plus early experimental works, and appears to be much better than any other earlier correlations. The limitations of the new correlation equation, as well as those of all earlier ones, were also discussed. Copyright 1999 Academic Press.

Particle Detachment in Deep Bed Filtration

The paper examines the behavior of particle detachment in deep bed filtration and the dependence of particle detachment on several filtration operating parameters. Theoretical analysis was carried out by considering the balance of various relevant interaction forces. Based on the results, experiments were conducted to study the effect of particle size, filter grain size, and headloss gradient on particle detachment in deep bed filtration. In one set of experiments, the filter was operated at constant filtration rate in order to build up the headloss across the filter bed continuously. In the other set of experiments, the filter in operation was allowed to experience a short period of flow shock (i.e., to be subject to a higher flow rate during this period). Both sets of experiments confirmed the dependence of particle detachment on particle size, collector gain size, and headloss gradient (degree of filter clogging) of the filter, as predicted by the analysis.