Cardiovascular and Metabolic Consequences of Liver Transplantation: A Review

Modification of Cardiovascular Risk Factors and the Evolution of The Cardiovascular Phenotype of Liver Transplant Recipients in the Long -Term Postoperative Period

AIM

To evaluate the contribution of traditional and additional cardiovascular risk factors (CVRFs) to the development of chronic ischemic heart disease (CIHD) in liver transplant recipients during the long-term postoperative period.

MATERIAL AND METHODS

A single-center prospective cohort study was conducted. The study included 740 patients with chronic end-stage liver disease (CESLD) and cirrhotic cardiomyopathy (CCMP). During the observation period (5.4±2.29 years), patients were divided into two groups: liver transplant recipients (n=420) and patients with CESLD on the waiting list who did not receive a donor organ (n=320). In patients enrolled to the study upon inclusion in the waiting list, CVRFs, history, clinical and laboratory and instrumental data were studied at all stages of the hepato-cardiac continuum.

RESULTS

During the long-term postoperative period, liver transplant recipients belonged to the group of high cardiovascular risk: over a 5-year observation period, 35.7% (n=150) of them developed metabolic syndrome (MS), 9.8% developed verified CIHD associated with MS. The incidence of traditional CVRFs was high (arterial hypertension, 88.6%; obesity, 36.6%; hypercholesterolemia, 77.8%; hypertriglyceridemia, 43.6%; reduced concentration of high-density lipoprotein cholesterol, 35.4%; increased concentrations of low-density lipoprotein cholesterol, 66.8% and very low-density lipoprotein cholesterol, 51.2%; increased atherogenic index, 61.5%). During the long-term postoperative period as compared to the period when patients were on the waiting list, additional CVRFs appeared: increases in body mass index, calcium index, nitric oxide metabolites, endothelin-1, homocysteine, intercellular adhesion molecules VCAM-1 and ICAM-1, and decreases in endothelium-dependent vasodilation and glomerular filtration rate to less than 60 ml/min/1.73 m2. A model for the development of CIHD was created. The model uses a complex of independent risk factors and demonstrates a predictive accuracy of 84.6%.

CONCLUSION

The study results indicate a modification of CVRFs and a dynamic change in the cardiovascular phenotype of liver transplant recipients: progression of CCMP during their stay on the waiting list, regression of CCMP manifestations during the first 12 months after orthotopic liver transplantation, and increases in the total cardiovascular risk and likelihood of CIHD in the long-term postoperative period.

The Role of mTOR Inhibitors after Liver Transplantation for Hepatocellular Carcinoma

Liver transplantation is a treatment option for nonresectable patients with early-stage HCC, with more significant advantages when Milan criteria are fulfilled. An immunosuppressive regimen is required to reduce the risk of graft rejection after transplantation, and CNIs represent the drugs of choice in this setting. However, their inhibitory effect on T-cell activity accounts for a higher risk of tumour regrowth. mTOR inhibitors (mTORi) have been introduced as an alternative immunosuppressive approach to conventional CNI-based regimens to address both immunosuppression and cancer control. The PI3K-AKT-mTOR signalling pathway regulates protein translation, cell growth, and metabolism, and the pathway is frequently deregulated in human tumours. Several studies have suggested the role of mTORi in reducing HCC progression after LT, accounting for a lower recurrence rate. Furthermore, mTOR immunosuppression controls the renal damage associated with CNI exposure. Conversion to mTOR inhibitors is associated with stabilizing and recovering renal dysfunction, suggesting an essential renoprotective effect. Limitations in this therapeutic approach are related to their negative impact on lipid and glucose metabolism as well as on proteinuria development and wound healing. This review aims to summarize the roles of mTORi in managing patients with HCC undergoing LT. Strategies to overcome common adverse effects are also proposed.

Outcomes of Nonalcoholic Steatohepatitis After Liver Transplantation: An Updated Meta-Analysis and Systematic Review

BACKGROUND & AIMS

Nonalcoholic steatohepatitis (NASH) is the fastest growing indication of liver transplantation (LT) and is projected to be the leading cause of LT in the near future. The systemic pathogenesis of NASH increases risks of adverse clinical outcomes in patients with NASH receiving LT. Thus, this study aimed to conduct a time-dependent survival analysis between LT recipients with and without NASH using hazard ratios.

METHODS

A search was conducted on Medline and Embase databases for articles relating to LT outcomes for NASH recipients. A survival analysis was conducted of hazard ratios using the DerSimonian and Laird random-effects model with meta-regression. To account for censoring, survival data were reconstructed from published Kaplan-Meier curves and pooled to derive more accurate hazard estimates and all-cause mortality in NASH patients after LT. Pairwise meta-analysis was conducted to analyze secondary outcomes.

RESULTS

Fifteen studies involving 119,327 LT recipients were included in our analysis with a prevalence of NASH of 20.2% (95% CI, 12.9-30.2). The pooled 1-year, 5-year, and 10-year all-cause mortality in NASH patients after LT were 12.5%, 24.4%, and 37.9%, respectively. Overall survival was comparable between LT recipients for NASH vs non-NASH (hazard ratio, 0.910; 95% CI, 0.760 to 1.10; P = .34). Meta-regression showed that a higher model for end-stage liver disease score was associated with significantly worse overall survival in NASH compared with non-NASH after LT (95% CI, -0.0856 to -0.0181; P = .0026).

CONCLUSIONS

This study shows that patients undergoing LT for NASH cirrhosis have comparable complication rates, overall survival, and graft survival compared with non-NASH patients, although close monitoring may be indicated for those with higher model for end-stage liver disease scores.

Metabolic syndrome after liver transplant in patients at the specialized Center San Vicente Fundación, Rionegro, Antioquia, Colombia, 2013-2017

OBJECTIVES.

Motivation for the study: there is a lack of studies in Latin America on the frequency of metabolic syndrome in patients who receive liver transplants. Main findings: two-thirds (66%) of patients who received liver transplantation between 2013 and 2017 at the Specialized Center San Vicente Fundación de Rionegro, Antioquia, Colombia, subsequently presented metabolic syndrome. Implications: this study confirms that liver transplant recipients very frequently develop metabolic syndrome; however, the frequency found by this study (66%) was almost double that reported in other regions of the world, suggesting that patients from the Specialized Center San Vicente Fundación de Rionegro, Antioquia, Colombia, may present some additional condition. The medical records of all liver transplant patients attended at the Centro Especializado San Vicente Fundación between January 2013 and June 2017 were reviewed in order to determine the frequency of post-transplant metabolic syndrome (MS). We collected sociodemographic data, pathological history, toxicological history, complications, and ATP III criteria in a validated instrument. The statistical analysis was carried out with OpenEpi 3.01; p<0.05 was considered as statistically significant. Of the 102 reviewed medical records, 73 met the inclusion criteria (no MS diagnosis prior to transplant and complete information for the instru-ment) and were analyzed. Most patients were male (59%), older adults (64%) and married (62%). The frequency of MS after liver transplant was 66%. The association between MS and history of hypertension and diabetes was significant. We confirmed that MS is a frequent complication in liver transplant recipients and that history of hypertension and diabetes are the most frequent associated factors.

Cardiovascular disease risk in liver transplant recipients transplanted due to chronic viral hepatitis

Background

Cardiovascular disease (CVD) is a major cause of morbidity and mortality after liver transplantation, mostly in patients transplanted for nonalcoholic steatohepatitis, obesity and diabetes. Few data exist on cardiovascular diseases among patients transplanted for viral hepatitis.

Objective

Our aim is to clarify the cardiovascular risk and subclinical vascular damage among liver transplant recipients for chronic viral hepatitis (i.e. hepatits C virus, hepatis B virus and hepatitis D virus infection).

Methods

Adult patients (age ≥ 18 years) with orthotopic liver transplants (OLT) due to viral hepatitis who signed informed consent, and were admitted for a routine follow-up between June 2019 and September 2020 at the Infectious Disease outpatient clinic of the University of Campania Luigi Vanvitelli, Naples, Italy, were prospectively enrolled. An estimation of cardiovascular risk was assessed using three main risk charts, echocolor-Doppler of epiaortic vessels was performed to assess subclinical Intima-Media changes.

Results

A total of 161 patients were evaluated; of these 15 were excluded because not affected by viral hepatitis. 146 patients were considered. 83 patients (56.8%) were considered at high cardiovascular risk according to Framingham, 54 patients (36.9%) to American Heart Association Arteriosclerotic Cardiovascular Disease (ASCVD) score and 19 (13.0%) to Heart Score. Only 8 patients (5.4%) showed a normal carotid ultrasound, while 52 patients (35.6%) had a carotid artery Intima-Media Thickness (IMT) and 86 (58.9%) an atherosclerotic plaque.

Conclusions

Liver transplant recipients for virus-related associated liver disease are, in light of the high percentage of carotid lesions, at high risk of CVD. Risk charts compared to subclinical carotid lesions which represent damage already established and a real localization of the disease, seem to underestimate the cardiovascular risk. A chronic inflammatory status, could play a key role. It’s important to raise the awareness of cardiovascular risk in liver transplant patients to prevent cardiovascular diseases and improve the timing of early diagnosis of premature vascular lesions.

Ex vivo generation of regulatory T cells from liver transplant recipients using costimulation blockade

The potential of adoptive cell therapy with regulatory T cells (Tregs) to promote transplant tolerance is under active exploration. However, the impact of specific transplant settings and protocols on Treg manufacturing is not well-delineated. Here, we compared the use of peripheral blood mononuclear cells (PBMCs) from patients before or after liver transplantation to the use of healthy control PBMCs to determine their suitability for Treg manufacture using ex vivo costimulatory blockade with belatacept. Despite liver failure or immunosuppressive therapy, the capacity for Treg expansion during the manufacturing process was preserved. These experiments did not identify performance or quality issues that disqualified the use of posttransplant PBMCs-the currently favored protocol design. However, as Treg input correlated with output, significant CD4-lymphopenia in both pre- and posttransplant patients limited Treg yield. We therefore turned to leukapheresis posttransplant to improve absolute yield. To make deceased donor use feasible, we also developed protocols to substitute splenocytes for PBMCs as allostimulators. In addition to demonstrating that this Treg expansion strategy works in a liver transplant context, this preclinical study illustrates how characterizing cellular input populations and their performance can both inform and respond to clinical trial design and Treg manufacturing requirements.

Predictive Cardiometabolic Risk Profiling of Patients Using Vascular Age in Liver Transplantation

Liver transplantation is the last therapeutic option in patients with end-stage liver diseases. The adequate clinical management of transplant-patients impacts their vital prognosis and decisions on many occasions are made from the interaction of multiple variables involved in the process. This work is based on the National Liver Transplantation Program in Uruguay. We performed predictive analysis of cardiometabolic diseases on the transplanted cohort between 2014 and 2019, considering vascular age as a key factor. This aims at classification of the cohort based on the vascular age of the evaluated patients before transplantation for risk-profiling. Predicted high-risk group of the patients showed substantial deterioration of post-transplant health-conditions, including higher mortality rate. In our knowledge, this is the first study in Latin America incorporating vascular age toward predictive analysis of cardiometabolic risk factors in liver transplantations. Predictive risk-modeling using vascular age in a pre-transplantation scenario provides significant opportunity for early prediction of post-transplant risk factors, leading to efficient treatment with anticipation.

Heterogeneity of antigenic constellation in human hepatocellular carcinoma

Hepatocellular carcinoma is one of the primary liver malignancies responsible for over a million deaths per year worldwide (approximately 10% of all deaths in the adult age range). The diagnosis of HCC can be difficult and often requires the use of more than one microscopic technique. A retrospective study was performed on a study batch of 42 cases that died of HCC due to metastasis or other secondary complications. Tissue samples were taken in order to investigate the tumour antigenic constellation by means of IHC method using a large variety of antibodies. In situ hybridization was also performed for albumin mRNA to assess the albumin expression in some selected cases. Telomerase activity was investigated using IHC method for the hTERT catalytic subunit. A cocktail of hepatic cytokeratins (CK8, 18) combined with Hep Par-1 and associated to albumin proved to be more powerful than albumin alone in differentiating HCC and increased the value of tumour diagnosis. hTERT expression was proportionally reverse to the tumour degree of differentiation, but was independent from the expression of tumour-proliferating indexes. The heterogeneity of the antigenic constellation in hepatocellular carcinoma suggests an antigenic mosaicism, which can be expressed a synchronous or metachronous manner, depending on the tumour degree of differentiation.