Hepatic steatosis and liver fat contents in liver transplant recipients are associated with serum adipokines and insulin resistance

Post-Liver Transplant Metabolic Syndrome

Non-alcoholic steatohepatitis (NASH) is the second most frequent cause of liver transplantation following alcoholic liver disease. With longer follow-up and increased survival rates, the occurrence rate of the metabolic syndrome is increasing with time among liver transplant recipients. Reappearances of non-alcoholic fatty liver disease after transplantation, both as recurring cases and new instances, are prevalent; nonetheless, the recurrence of fibrosis is minimal. Recognizing populations at elevated risk and enhancing the management of metabolic-related conditions are crucial for maintaining a healthy transplanted organ, particularly considering the prolonged utilization of immunosuppressive treatments. Furthermore, NASH-related cirrhosis patients who had transplant are at a greater risk of cardiovascular, renal events and increased incidence of cancer, necessitating a unique care strategy. This review discusses post-transplant metabolic syndrome, risk factors, pathogenesis, diagnosis, prevention strategy, recurrent and de novo NAFLD and customized immunosuppression.

Prevalence and predictors of metabolic-associated fatty liver disease in liver transplant recipients: A cross-sectional prospective study

Background and Aim

Metabolic-associated fatty liver disease (MAFLD) has emerged as a significant global health concern. However, the prevalence and predictors of MAFLD in post-liver transplantation (LT) patients remain uncertain. This study aimed to determine the prevalence and predictors of MAFLD in LT recipients and to assess the effectiveness of controlled attenuation parameter (CAP) values in diagnosing post-transplant MAFLD.

Materials and Methods

A cross-sectional prospective study was conducted involving 128 adult patients who had undergone LT, and had received liver imaging, and vibration-controlled transient elastography (VCTE). MAFLD was diagnosed on the basis of the presence of liver steatosis detected through imaging and specific metabolic risk abnormalities.

Results

The prevalence of MAFLD after LT was 34.4%, with 22.1% categorized as de novo MAFLD, and 12.3% as recurrent MAFLD. Posttransplant diabetes (OR: 4.88; 95% CI 1.30-18.34; p=0.019) and higher CAP values (OR: 1.04; 95% CI 1.02-1.06; p=0000) were identified as independent predictors of post-LT MAFLD. A CAP cutoff value of 270 dB/m exhibited an area under the receiver operating curve of 0.84 in detecting MAFLD.

Conclusion

These findings underscore the notable prevalence of MAFLD in liver transplant recipients and suggest the potential utility of VCTE as a non-invasive tool for its detection.

NO-IL-6/10-IL-1β axis: a new pathway in steatotic and non-steatotic liver grafts from brain-dead donor rats

Introduction

Brain death (BD) and steatosis are both risk factors for organ dysfunction or failure in liver transplantation (LT).

Material and methods

Here, we examine the role of interleukin 6 (IL- 6) and IL-10 in LT of both non-steatotic and steatotic liver recovered from donors after brain death (DBDs), as well as the molecular signaling pathways underlying the effects of such cytokines.

Results

BD reduced IL-6 levels only in nonsteatotic grafts, and diminished IL-10 levels only in steatotic ones. In both graft types, BD increased IL-1β, which was associated with hepatic inflammation and damage. IL-6 administration reduced IL-1β only in non-steatotic grafts and protected them against damage and inflammation. Concordantly, IL-1β inhibition via treatment with an IL-1 receptor antagonist caused the same benefits in non-steatotic grafts. Treatment with IL-10 decreased IL-1β only in steatotic grafts and reduced injury and inflammation specifically in this graft type. Blockading the IL-1β effects also reduced damage and inflammation in steatotic grafts. Also, blockade of IL-1β action diminished hepatic cAMP in both types of livers, and this was associated with a reduction in liver injury and inflammation, then pointing to IL-1β regulating cAMP generation under LT and BD conditions. Additionally, the involvement of nitric oxide (NO) in the effects of interleukins was evaluated. Pharmacological inhibition of NO in LT from DBDs prompted even more evident reductions of IL-6 or IL-10 in non-steatotic and steatotic grafts, respectively. This exacerbated the already high levels of IL-1β seen in LT from DBDs, causing worse damage and inflammation in both graft types. The administration of NO donors to non-steatotic grafts potentiated the beneficial effects of endogenous NO, since it increased IL-6 levels, and reduced IL-1β, inflammation, and damage. However, treatment with NO donors in steatotic grafts did not modify IL-10 or IL-1β levels, but induced more injurious effects tan the induction of BD alone, characterized by increased nitrotyrosine, lipid peroxidation, inflammation, and hepatic damage.

Conclusion

Our study thus highlights the specificity of new signaling pathways in LT from DBDs: NO-IL-6-IL-1β in non-steatotic livers and NO-IL-10-IL-1β in steatotic ones. This opens up new therapeutic targets that could be useful in clinical LT.

Angiotensin receptor blockers might be protective against hepatic steatosis after liver transplantation

BACKGROUND

Hepatic steatosis is an increasing complication in liver transplant recipients. Currently, there is no pharmacologic therapy for treatment of hepatic steatosis after liver transplantation. The aim of this study was to determine the association between use of angiotensin receptor blockers (ARB) and hepatic steatosis in liver transplant recipients.

METHODS

We conducted a case-control analysis on data from Shiraz Liver Transplant Registry. Liver transplant recipients with and without hepatic steatosis were compared for risk factors including use of ARB.

RESULTS

A total of 103 liver transplant recipients were included in the study. Thirty five patients treated with ARB and 68 patients (66%) did not receive these medications. In univariate analysis, ARB use (P = 0.002), serum triglyceride (P = 0.006), weight after liver transplantation (P = 0.011) and etiology of liver disease (P = 0.008) were associated with hepatic steatosis after liver transplantation. In multivariate regression analysis, ARB use was associated with lower likelihood of hepatic steatosis in liver transplant recipients (OR = 0.303, 95% CI: 0.117-0.784; P = 0.014). Mean duration of ARB use (P = 0.024) and mean cumulative daily dose of ARB (P = 0.015) were significantly lower in patients with hepatic steatosis.

CONCLUSION

Our study showed that ARB use was associated with reduced incidence of hepatic steatosis in liver transplant recipients.

Hepatic steatosis after liver transplantation: a systematic review and meta-analysis

NAFLD can occur after liver transplantation (LT), as recurrence or de novo hepatic steatosis (HS). We aimed to evaluate the literature on prevalence, risk factors, and prognosis of post-LT HS. Systematic review with meta-analysis through a search on: PUBMED, Scopus, and Web-of-Science, from inception until the September 30, 2021. Forty studies were included, representing 6979 patients. The post-LT HS prevalence was 39.76% (95% CI, 34.06-45.46), with a rising kinetics (11.06% increase per decade, p =0.04), and a geographical distribution (15.10% more prevalent in American continent compared with Europe and Asia). Recurrent HS was up to 5-fold more likely than de novo HS [OR: 5.38 (2.69-10.76)]. Metabolic disturbances were stronger risk factors in the post-LT recipient [obesity: OR: 4.62 (3.07-6.96); metabolic syndrome: OR: 3.26 (2.03-5.25)] as compared with pre-LT recipients, with the exception of diabetes mellitus, which doubled the risk at any set [pre-LT diabetes mellitus: OR: 2.06 (1.58-2.68); post-LT diabetes mellitus: OR: 2.12 (1.73-2.59)]. Donor factors were not the relevant risk factors for post-LT HS and the only immunosuppressive drug associated with increased risk was sirolimus [OR: 1.68 (1.07-2.64)]. The prevalence of post-LT steatohepatitis was 28.82% (19.62-38.03) and the strongest risk factor was pre-LT NAFLD. Limited outcomes data suggest that post-LT HS did not increase the risk for liver cirrhosis or mortality in these studies. Two out of 5 patients submitted to LT will develop post-LT HS, being recurrent HS more common than de novo HS. Diabetes mellitus and post-LT metabolic syndrome are the strongest risk factors for HS and baseline NAFLD for steatohepatitis. All transplanted patients should be enrolled in lifestyle interventions to prevent post-LT metabolic syndrome, and sirolimus should be avoided in high-risk patients.

Metabolic syndrome, hepatic fibrosis, and steatosis diagnosed by liver stiffness measurement and controlled attenuation parameter after liver transplantation: the impact on long-term survival

BACKGROUND

Liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) are used for diagnosis of liver fibrosis and steatosis. This study aimed to noninvasively evaluate hepatic steatosis and fibrosis in liver transplant recipients using CAP and LSM and the impact on survival of patients.

METHODS

In a prospective study, adult liver transplant recipients were included. CAP and LSM obtained during transient elastography (TE) were used for assessment of hepatic steatosis and fibrosis. Patients were followed during 4 years for mortality as the main outcome after liver transplantation.

RESULTS

From 296 patients, 24.7% and 25% of liver transplant recipients had liver steatosis and fibrosis in CAP and LSM, respectively. In multivariable Cox regression analysis, etiology of liver disease (NASH versus non-NASH) (HR: 3.125; 95% CI: 1.594-6.134; p = 0.001), and post-transplant diabetes mellitus (PTDM) (HR: 2.617; 95% CI: 1.396-4.926; p = 0.003) were associated with hepatic steatosis after liver transplantation.  In multivariable Cox regression analysis, liver fibrosis was an independent predictor of mortality after liver transplantation (HR: 4.926; 95%CI: 1.779-13.513; p = 0.002).

CONCLUSION

CAP and LS measurement during TE are useful methods for diagnosis of hepatic steatosis and fibrosis in liver transplant recipients. LS measurement might predict long-term survival of patients.

Variations in TM6SF2, PCSK9 and PCSK7 genes and risk of hepatic steatosis after liver transplantation: a cross-sectional study

Background

Genetic abnormalities might have important role in pathogenesis of hepatic steatosis after liver transplantation. We aimed to investigate association between genetic variations in transmembrane 6 superfamily member 2 (TM6SF2) rs58542926, proprotein convertase subtilisin/kexin type 9 (PCSK9) rs505151 and proprotein convertase subtilisin/kexin type 7 (PCSK7) rs2277287 with hepatic steatosis in liver transplant recipients.

Methods

In a cross-sectional study, adult (> 18 years) liver transplant recipients who were referred for their routine post-transplant follow-up between June 2018 and September 2018 were included in the study. Hepatic steatosis in transplant recipients was assessed by controlled attenuation parameter (CAP). Polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) was used to study TM6SF2 rs58542926, PCSK7 rs2277287 and PCSK9 rs505151 genotypes.

Results

107 liver transplant recipients were included. There was no association between different genotypes of PCSK9 rs505151 and PCSK7 rs2277287 with hepatic steatosis in liver transplant recipients (P value > 0.05). The presence of TT genotype of TM6SF2 rs58542926 was higher in patients with hepatic steatosis measured by CAP after liver transplantation. In patients with moderate and severe hepatic steatosis (grade 2 and 3 steatosis), AG + GG genotypes of PCSK9 rs505151 were more prevalent than AA genotype (OR 8.667; 95% CI 1.841–40.879; P value = 0.004) compared to patients with mild steatosis (grade 1). In multivariate regression model, AG + GG genotypes of PCSK9 rs505151 were associated with moderate and severe steatosis in liver transplant recipients (OR 5.747; 95% CI 1.086–30.303; P value = 0.040).

Conclusions

Genetic variations in TM6SF2 rs58542926 and PCSK9 rs505151 might be associated with hepatic steatosis in liver transplant recipients.

Role of Leptin in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD), which affects about a quarter of the global population, poses a substantial health and economic burden in all countries, yet there is no approved pharmacotherapy to treat this entity, nor well-established strategies for its diagnosis. Its prevalence has been rapidly driven by increased physical inactivity, in addition to excessive calorie intake compared to energy expenditure, affecting both adults and children. The increase in the number of cases, together with the higher morbimortality that this disease entails with respect to the general population, makes NAFLD a serious public health problem. Closely related to the development of this disease, there is a hormone derived from adipocytes, leptin, which is involved in energy homeostasis and lipid metabolism. Numerous studies have verified the relationship between persistent hyperleptinemia and the development of steatosis, fibrinogenesis and liver carcinogenesis. Therefore, further studies of the role of leptin in the NAFLD spectrum could represent an advance in the management of this set of diseases.