Impact of metabolic disorders on gallstone disease and perioperative recovery after laparoscopic cholecystectomy

BACKGROUND

Gallstone disease (GSD), nonalcoholic fatty liver disease (NAFLD), metabolic dysfunction-associated fatty liver disease (MAFLD), and metabolic syndrome (MetS) are common medical disorders worldwide. This study aimed to ascertain how NAFLD, MAFLD, MetS, and other factors affect the development of GSD, and how the GSD-associated factors influence patient recovery after laparoscopic cholecystectomy (LC).

METHODS

We included 200 patients who were diagnosed with GSD and underwent LC between January 2017 and February 2022. A total of 200 subjects without GSD and "non-calculous causes" during the same period were also included as controls. We compared the metabolic disorder differences between GSD patients and controls. Furthermore, we sub-grouped patients based on the comorbidities of preoperative NAFLD, MAFLD, and MetS, and compared the impacts of these comorbidities on short-term post-LC functional recovery of the patients.

RESULTS

The prevalence of NAFLD and MetS were higher in GSD patients (P < 0.05). Based on multivariate logistic regression analysis, hyperglycemia [odds ratio (OR) = 2.2, 95% confidence interval (CI): 1.4-3.4, P = 0.001] and low high-density lipoprotein cholesterol (HDL-C) level (OR = 1.8, 95% CI: 1.1-3.1, P = 0.048) were linked to GSD. NAFLD and MetS linked to liver enzymes after LC (P < 0.05). MetS also linked to the levels of inflammatory indicators after LC (P < 0.05). The obesity, hyperlipidemia, low HDL-C level, and hyperglycemia linked to liver enzymes after LC (P < 0.05). Hyperlipidemia, low HDL-C level, and hypertension linked to inflammation after LC (P < 0.05).

CONCLUSIONS

The prevalence of GSD may be linked to NAFLD and MetS. Hyperglycemia and low HDL-C level were independent risk factors of GSD.

Cholecystohepatic shunt pathway reduces secondary bile acid accumulation to enhance natural killer T cell-mediated anti-hepatocellular carcinoma immunity

BACKGROUND AND AIM

The impact of cholecystectomy, which blocks the cholecystohepatic shunt pathway (CHSP), on the prognosis of patients with hepatocellular carcinoma (HCC) is unclear. Hepatic secondary bile acids (BAs) inhibit natural killer T (NKT) cell-mediated immunity against HCC, and the regulation of homeostasis of hepatic secondary BAs is controlled by the CHSP. However, the influence of CHSP on NKT cell-mediated immunity against HCC remains unclear.

METHODS

The clinical data of hospitalized patients undergoing HCC resection were collected. Meanwhile, an in situ HCC mouse model was established, and the CHSP was augmented using oleanolic acid (OA).

RESULTS

After 1:1 propensity score matching, Cox regression analysis revealed that cholecystectomy was an independent risk factor for HCC recurrence after hepatectomy (P = 0.027, hazard ratio: 1.599, 95% confidence interval: 1.055-2.422). Experimentally, when OA enhanced CHSP, a significant decrease was observed in the accumulation of secondary BAs in the livers of mice. Additionally, a significant increase was observed in the levels of C-X-C ligand 16 and interferon γ in the serum and tumor tissues. Further, the percentage of C-X-C receptor 6 (+) NKT cells in the tumor tissues increased significantly, and the growth of liver tumors was inhibited.

CONCLUSIONS

This clinical study revealed that cholecystectomy promoted the recurrence after radical hepatectomy in patients with HCC. Preserving the normal-functioning gallbladder as much as possible during surgery may be beneficial to the patient's prognosis. Further investigation into the mechanism revealed that CHSP enhanced NKT cell-mediated immunity against HCC by reducing the hepatic accumulation of secondary BAs.

Metabolic-Dysfunction-Associated Steatotic Liver Disease (MASLD) after Liver Transplantation: A Narrative Review of an Emerging Issue

The development of steatotic liver disease after liver transplant (LT) is widely described, and epidemiological data have revealed an increased incidence in recent times. Its evolution runs from simple steatosis to steatohepatitis and, in a small proportion of patients, to significant fibrosis and cirrhosis. Apparently, post-LT steatotic disease has no impact on the recipient's overall survival; however, a higher cardiovascular and malignancy burden has been reported. Many donors' and recipients' risk factors have been associated with this occurrence, although the recipient-related ones seem of greater impact. Particularly, pre- and post-LT metabolic alterations are strictly associated with steatotic graft disease, sharing common pathophysiologic mechanisms that converge on insulin resistance. Other relevant risk factors include genetic variants, sex, age, baseline liver diseases, and immunosuppressive drugs. Diagnostic evaluation relies on liver biopsy, although non-invasive methods are being increasingly used to detect and monitor both steatosis and fibrosis stages. Management requires a multifaceted approach focusing on lifestyle modifications, the optimization of immunosuppressive therapy, and the management of metabolic complications. This review aims to synthesize the current knowledge of post-LT steatotic liver disease, focusing on the recent definition of metabolic-dysfunction-associated steatotic liver disease (MASLD) and its metabolic and multisystemic concerns.

Multi-omics analysis reveals a crosstalk between ferroptosis and peroxisomes on steatotic graft failure after liver transplantation

To identify the mechanism underlying macrosteatosis (MaS)-related graft failure (GF) in liver transplantation (LT) by multi-omics network analysis. The transcriptome and metabolome were assayed in graft and recipient plasma in discovery (n = 68) and validation (n = 89) cohorts. Differentially expressed molecules were identified by MaS and GF status. Transcriptional regulatory networks were generated to explore the mechanism for MaS-related inferior post-transplant prognosis. The differentially expressed molecules associated with MaS and GF were enriched in ferroptosis and peroxisome-related pathways. Core features of MaS-related GF were presented on decreased transferrin and impaired anti-oxidative capacity dependent upon dysregulation of transcription factors hepatocyte nuclear factor 4A (HNF4A) and hypoxia-inducible factor 1A (HIF1A). Furthermore, miR-362-3p and miR-299-5p inhibited transferrin and HIF1A expression, respectively. Lower M2 macrophages but higher memory CD4 T cells were observed in MaS-related GF cases. These results were validated in clinical specimens and cellular models. Systemic analysis of multi-omics data depicted a panorama of biological pathways deregulated in MaS-related GF. Transcriptional regulatory networks centered on transferrin and anti-oxidant responses were associated with poor MaS graft quality, qualifying as potential targets to improve prognosis of patients after LT.

Comorbidity of patients with noncommunicable diseases in general practice. Eurasian guidelines

Создание руководства поддержано Советом по терапевтическим наукам отделения клинической медицины Российской академии наук.

Resistance to Cholesterol Gallstone Disease: Hepatic Cholesterol Metabolism

Cholesterol gallstone disease (CGD) is one of the most common digestive diseases, and it is closely associated with hepatic cholesterol metabolism. Cholesterol gallstones may be caused by abnormal hepatic cholesterol metabolism, such as excessive cholesterol biosynthesis within the liver, interfering with the uptake or export of cholesterol in the liver, and abnormal hepatic cholesterol esterification. In this review, we begin with a brief overview of the clinical diagnosis and treatment of gallstone disease (GSD). Then, we briefly describe the major processes of hepatic cholesterol metabolism and summarize the key molecular expression changes of hepatic cholesterol metabolism in patients with gallstones. We review and analyze the recent advances in elucidating the relationships between these key molecules and CGD, and some targets significantly impacting on CGD via hepatic cholesterol metabolism are also listed. We also provide a significant discussion on the relationship between CGD and nonalcoholic fatty liver disease (NAFLD). Finally, the new discoveries of some therapeutic strategies associated with hepatic cholesterol metabolism to prevent and treat CGD are summarized.

Effect of donor HSD17B13 genotype on patient survival after liver transplant: a retrospective cohort study

Background

Several genetic variants are associated with chronic liver disease. The role of these variants in outcomes after liver transplantation (LT) is uncertain. The aim of this study was to determine if donor genotype at risk-associated variants in PNPLA3 (rs738409 C>G, p.I148M) and HSD17B13 (rs72613567 T>TA; rs80182459, p.A192Lfs∗8) influences post-LT survival.

Methods

In this retrospective cohort study, data on 2346 adults who underwent first-time LT between January 1, 1999 and June 30, 2020 and who had donor DNA samples available at five large Transplant Immunology Laboratories in Texas, USA, were obtained from the United Network for Organ Sharing (UNOS). Duplicates, patients with insufficient donor DNA for genotyping, those who were <18 years of age at the time of transplant, had had a previous transplant or had missing genotype data were excluded. The primary outcomes were patient and graft survival after LT. The association between donor genotype and post-LT survival was examined using Kaplan-Meier method and multivariable-adjusted Cox proportional hazards models.

Findings

Median age of LT recipients was 57 [interquartile range (IQR), 50-62] years; 837 (35.7%) were women; 1362 (58.1%) White, 713 (30.4%) Hispanic, 182 (7.8%) Black/African-American. Median follow-up time was 3.95 years. Post-LT survival was not affected by donor PNPLA3 genotype but was significantly reduced among recipients of livers with two HSD17B13 loss-of-function (LoF) variants compared to those receiving livers with no HSD17B13 LoF alleles (unadjusted one-year survival: 82.6% vs 93.9%, P < 0.0001; five-year survival: 73.1% vs 82.9%, P = 0.0017; adjusted hazard ratio [HR], 2.25; 95% CI, 1.61-3.15 after adjustment for recipient age, sex, and self-reported ethnicity). Excess mortality was restricted to those receiving steroid induction immunosuppression (crude 90-day post-LT mortality, 9.3% [95% CI, 1.9%-16.1%] vs 1.9% [95% CI, 0.9%-2.9%] in recipients of livers with two vs no HSD17B13 LoF alleles, P = 0.0012; age, sex, and ethnicity-adjusted HR, 2.85; 95% CI, 1.72-4.71, P < 0.0001). No reduction was seen among patients who did not receive steroid induction (90-day mortality 3.1% [95% CI, 0%-7.3%] vs 2% [95% CI, 0.9%-3.1%], P = 0.65; adjusted HR, 1.17; 95% CI, 0.66-2.08, P = 0.60).

Interpretation

Donor HSD17B13 genotype adversely affects post-LT survival in patients receiving steroid induction. Additional studies are required to confirm this association.

Funding

The National Institutes of Health and American Society of Transplant Surgeons Collaborative Scientist Grant.

Multi-omics network analysis on samples from sequential biopsies reveals vital role of proliferation arrest for Macrosteatosis related graft failure in rats after liver transplantation

To investigate the molecular impact of graft MaS on post-transplant prognosis, based on multi-omics integrative analysis. Rats were fed by methionine-choline deficient diet (MCD) for MaS grafts. Samples were collected from grafts by sequential biopsies. Transcriptomic and metabolomic profilings were assayed. Post-transplant MaS status showed a close association with graft failure. Differentially expressed genes (DEGs) for in-vivo MaS were mainly enriched on pathways of cell cycle and DNA replication. Post-transplant MaS caused arrests of graft regeneration via inhibiting the E2F1 centered network, which was confirmed by an in vitro experiment. Data from metabolomics assays found insufficient serine/creatine which is located on one‑carbon metabolism was responsible for MaS-related GF. Pre-transplant MaS caused severe fibrosis in long-term survivors. DEGs for grafts from long-term survivors with pre-transplant MaS were mainly enriched in pathways of ECM-receptor interaction and focal adhesion. Transcriptional regulatory network analysis confirmed SOX9 as a key transcription factor (TF) for MaS-related fibrosis. Metabolomic assays found elevation of aromatic amino acid (AAA) was a major feature of fibrosis in long-term survivors. Graft MaS in vivo increased post-transplant GF via negative regulations on graft regeneration. Pre-transplant MaS induced severe fibrosis in long-term survivors via activations on ECM-receptor interaction and AAA metabolism.

A Machine Learning-Based Method for Detecting Liver Fibrosis

Cholecystectomy and Metabolic-associated steatotic liver disease (MASLD) are prevalent conditions in gastroenterology, frequently co-occurring in clinical practice. Cholecystectomy has been shown to have metabolic consequences, sharing similar pathological mechanisms with MASLD. A database of MASLD patients who underwent cholecystectomy was analysed. This study aimed to develop a tool to identify the risk of liver fibrosis after cholecystectomy. For this purpose, the extreme gradient boosting (XGB) algorithm was used to construct an effective predictive model. The factors associated with a better predictive method were platelet level, followed by dyslipidaemia and type-2 diabetes (T2DM). Compared to other ML methods, our proposed method, XGB, achieved higher accuracy values. The XGB method had the highest balanced accuracy (93.16%). XGB outperformed KNN in accuracy (93.16% vs. 84.45%) and AUC (0.92 vs. 0.84). These results demonstrate that the proposed XGB method can be used as an automatic diagnostic aid for MASLD patients based on machine-learning techniques.

Association of nonalcoholic fatty liver disease with acute cholangitis: a nationwide propensity-matched analysis from the United States

Background

Nonalcoholic fatty liver disease (NAFLD) has previously been linked to several disease states with an impact on patient outcomes. However, clinical evidence on the association between NAFLD and acute cholangitis (AC) remains scarce. We aimed to evaluate the potential association between NAFLD and AC.

Methods

We conducted a retrospective cohort study using the US National Inpatient Sample database from 2016 to 2019 to analyze primary AC hospitalizations with NAFLD compared to non-NAFLD in a 1:1 propensity-matched population.

Results

A total of 1550 AC patients with NAFLD were matched to 1550 AC patients without NAFLD. NAFLD had a higher association with AC when compared to patients without NAFLD, with an odds ratio of 2.33 (95% CI [1.81-3.0], P < 0.001). The length of stay was higher in NAFLD than in non-NAFLD (4 vs 3 days, P < 0.001). The median inpatient charges in NAFLD were also higher than in the non-NAFLD cohort ($36,182 vs $35,244, P < 0.001). Inpatient mortality was higher in NAFLD compared to non-NAFLD (1.6% vs 0%, P < 0.001). There was an increased prevalence of portal vein thrombosis (3.2% vs 0%), acute kidney injury (24.2% vs 17.7%), sepsis (3.2% vs 1.6%), mechanical ventilation (3.2% vs 0%), and percutaneous cholecystostomy tube insertion (3.2% vs 1.6%) in NAFLD compared to non-NAFLD (P < 0.05). NAFLD also had a higher association with acute cholecystitis, with an odds ratio of 3.70 (95% CI [3.19-4.29], P < 0.001).

Conclusions

This study showed an association between NALFD and AC, resulting in increased length of stay, hospital charges, and inpatient mortality. Underlying NAFLD also increases acute complications of AC.

Metabolic mechanisms for and treatment of NAFLD or NASH occurring after liver transplantation

The rising tide of non-alcoholic fatty liver disease (NAFLD) associated with the obesity epidemic is a major health concern worldwide. NAFLD - specifically its more advanced form, non-alcoholic steatohepatitis (NASH)-related cirrhosis - is now the fastest growing indication for liver transplantation in the USA and Europe. Although the short-term and mid-term overall survival rates of patients who receive a liver transplant for NASH-related cirrhosis are essentially similar to those of patients who receive a transplant for other liver indications, recipients with NASH-related cirrhosis have an increased risk of waiting-list mortality and of developing recurrent liver disease and cardiometabolic complications in the longer term after liver transplantation. This Review provides a brief overview of the epidemiology of NAFLD and NASH and the occurrence of NAFLD or NASH in patients after liver transplantation for NASH and other liver indications. It also discusses the putative metabolic mechanisms underlying the emergence of NAFLD or NASH after liver transplantation as well as optimal therapeutic approaches for recipients of liver transplants, including the management of cardiometabolic comorbidities, tailored immunosuppression, lifestyle changes and pharmacotherapy for NAFLD.

Recent Progress and Future Direction for the Application of Multiomics Data in Clinical Liver Transplantation

Omics data address key issues in liver transplantation (LT) as the most effective therapeutic means for end-stage liver disease. The purpose of this study was to review the current application and future direction for omics in LT. We reviewed the use of multiomics to elucidate the pathogenesis leading to LT and prognostication. Future directions with respect to the use of omics in LT are also described based on perspectives of surgeons with experience in omics. Significant molecules were identified and summarized based on omics, with a focus on post-transplant liver fibrosis, early allograft dysfunction, tumor recurrence, and graft failure. We emphasized the importance omics for clinicians who perform LTs and prioritized the directions that should be established. We also outlined the ideal workflow for omics in LT. In step with advances in technology, the quality of omics data can be guaranteed using an improved algorithm at a lower price. Concerns should be addressed on the translational value of omics for better therapeutic effects in patients undergoing LT.

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.

Association between PNPLA3 rs738409 polymorphism and nonalcoholic fatty liver disease: a systematic review and meta-analysis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a common disorder that is known to be the leading cause of chronic liver disease worldwide. This study aims to systematically review and meta-analyze the association between PNPLA3 rs738409 polymorphism and non-alcoholic fatty liver.

METHODS

Following a systematic review and meta-analysis method, articles without any time limitation, were extracted from SID, MagIran, IranDoc, Scopus, Embase, Web of Science (WoS), PubMed and ScienceDirect international databases. Random effects model was used for analysis, and heterogeneity of studies was investigated considering the I² index and using Comprehensive Meta-Analysis software.

RESULTS

The odds ratio of CC genotype in patients with non-alcoholic fatty liver demonstrates the protective effect of CC genotype with the ratio of 0.52, whereas CG genotype presents an increasing effect of CG genotype with the ratio of 0.19, and GG genotype also showed an increasing effect of GG genotype with the ratio of 1.05. Moreover, CG + GG genotypes as a single group demostrated an odds rartio of 0.88.

CONCLUSION

This meta-analysis highlights that people with CC genotype has 52% lower chance of developing non-alcoholic fatty liver disease, and those with CG genotype had 19% higher risk of developing non-alcoholic fatty liver. Those with GG genotype were 105% more likely to develop non-alcoholic fatty liver than others. Moreover, those present in a population with CG + GG genotypes were 88% more likely to have non-alcoholic fatty liver disease.

Clinical and Genetic Risk Factors of Recurrent Nonalcoholic Fatty Liver Disease After Liver Transplantation

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) has been increasingly reported among recipients of liver transplantation (LT). We aimed to identify clinical and genetic risk factors responsible for the development of early recurrent NAFLD in nonalcoholic steatohepatitis transplant recipients.

METHODS

Forty-six total single nucleotide polymorphisms with known association with NAFLD were tested among both recipient and donor liver samples in 66 LT recipients with nonalcoholic steatohepatitis to characterize influences on NAFLD recurrence at ∼1 year post-LT (median interval from LT to biopsy: 377 days).

RESULTS

Recurrent NAFLD was identified in 43 (65.2%) patients, 20 (30.3%) with mild recurrence, and 23 (34.8%) with moderate to severe NAFLD. On adjusted analysis, change in the body mass index (BMI) (ΔBMI) was significantly associated with NAFLD recurrence, whereas post-LT diabetes mellitus was associated with increased severity of NAFLD recurrence. ADIPOR1 rs10920533 in the recipient was associated with increased risk of moderate to severe NAFLD recurrence, whereas the minor allele of SOD2 rs4880 in the recipient was associated with reduced risk. Similar reduced risk was noted in the presence of donor SOD2 rs4880 and HSD17B13 rs6834314 polymorphism.

DISCUSSION

Increased BMI post-LT is strongly associated with NAFLD recurrence, whereas post-LT diabetes mellitus was associated with increased severity of NAFLD recurrence. Both donor and recipient SOD2 rs4880 and donor HSD17B13 rs6834314 single nucleotide polymorphisms may be associated with reduced risk of early NAFLD recurrence, whereas presence of the minor allele form of ADIPOR1 rs10920533 in the recipient is associated with increased severity NAFLD recurrence.

Donor PNPLA3 and TM6SF2 Variant Alleles Confer Additive Risks for Graft Steatosis After Liver Transplantation

BACKGROUND

The rs58542926 polymorphism in transmembrane 6 superfamily member 2 (TM6SF2) is a genetic factor predisposing to nonalcoholic fatty liver disease. We aimed to explore the effect of recipient and donor TM6SF2 rs58542926 genotypes on liver graft fat content after liver transplantation.

METHODS

Steatosis was evaluated in liver biopsies from 268 adult recipients. The influence of recipient and donor TM6SF2 genotypes, patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 genotypes, and nongenetic factors on the steatosis grade assessed 6-30 months after transplantation was analyzed by ordinal logistic regression.

RESULTS

The presence of the TM6SF2 c.499A allele in the donor (P = 0.014), PNPLA3 c.444G allele in the donor (P < 0.001), posttransplant body mass index (P < 0.001), and serum triglycerides (P = 0.047) independently predicted increased liver fat content on multivariable analysis, whereas noncirrhotic liver disease, as an indication for liver transplantation, was associated with lower risk of steatosis (P = 0.003). The effects of the donor TM6SF2 A and PNPLA3 G alleles were additive, with an odds ratio of 4.90 (95% confidence interval, 2.01-13.00; P < 0.001), when both minor alleles were present compared with an odds ratio of 2.22 (95% confidence interval, 1.42-3.61; P = 0.002) when only one of these alleles was present.

CONCLUSIONS

The donor TM6SF2 c.499A allele is an independent risk factor of liver graft steatosis after liver transplantation that is additive to the effects of donor PNPLA3 c.444G allele.

Nonalcoholic Steatohepatitis After Liver Transplantation

Currently, nonalcoholic steatohepatitis (NASH) is the second leading indication for liver transplantation (LT), behind alcohol-related liver disease. After transplant, both recurrent and de novo nonalcoholic fatty liver disease are common; however, recurrence rates of NASH and advanced fibrosis are low. Identification of high-risk groups and optimizing treatment of metabolic comorbidities both before and after LT is paramount to maintaining a healthy allograft, especially with the additional consequences of longterm immunosuppression. In addition, NASH LT recipients are at an increased risk of cardiovascular events and malignancy, and their condition warrants a tailored approach to management. The optimal approach to NASH LT recipients including metabolic comorbidities management, tailored immunosuppression, the role of bariatric surgery, and nutritional and pharmacotherapy of NASH are discussed in this review. Overall, aggressive management of metabolic syndrome after LT via medical and surgical modalities and a minimalist approach to immunosuppression is advised.

Liver Transplantation for Nonalcoholic Steatohepatitis: Pathophysiology of Recurrence and Clinical Challenges

Nonalcoholic steatohepatitis is the fastest-growing indication for the liver transplant and a leading cause of hepatocellular carcinoma among patients listed for liver transplantation in the USA. Post-transplant nonalcoholic hepatic steatosis and steatohepatitis are frequent complications of liver transplantation. Nonalcoholic steatohepatitis poses a significant challenge in both pre- and post-transplant period due to its association with metabolic syndrome, coronary artery disease, chronic kidney disease, and obstructive sleep apnea. While optimal therapy is not yet available in the post-liver transplant setting, lifestyle interventions continue to remain as the mainstay of therapy for post-transplant nonalcoholic steatohepatitis. Early recognition with protocol biopsies and noninvasive modalities, along with modification of known risk factors, are the most effective methods to curtail the progression of nonalcoholic steatohepatitis in the absence of FDA-approved pharmacologic therapy.

Meta-analysis of the association between MBOAT7 rs641738, TM6SF2 rs58542926 and nonalcoholic fatty liver disease susceptibility

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a kind of liver disease caused by factors other than excessive alcohol use. It is the leading cause of liver injury in developed countries. The membrane-bound O-acyltransferase 7 (MBOAT7) and transmembrane 6 superfamily member 2 (TM6SF2) are associated with lipid metabolism. Studies found a mutation on MBOAT7, rs641738 and another on TM6SF2, rs58542926 were associated with liver diseases, including NAFLD. However, the results were inconclusive and inconsistent.

METHODS

In the present meta-analysis, the databases Pubmed, Embase, Chinese National Knowledge Infrastructure, and Chinse Biomedical Literature Database were searched for related studies. The deadline of publications was July 10th, 2018. The data from included studies were extracted by 2 independent investigators. STATA 12.0 software was used in the present meta-analysis.

RESULTS

A total of 9 papers with 20 studies, including 5415 cases and 17896 controls were identified for the meta-analysis. The results indicated lower risks of NAFLD for CC genotype of TM6SF2 rs58542926 in homozygous, heterozygous, dominant and recessive models (CC vs. TT: OR = 0.33; CC vs. CT: OR = 0.58; CC vs. CT + TT: OR = 0.64; CC + CT vs. TT: OR = 0.32). These decreased risks of NAFLD also existed in Asians in all genetic models except allelic model, and in Caucasians in the heterozygous model (CC vs. CT, OR = 0.52) and the dominant model (CC + CT vs. TT, OR = 0.50). No association existed between MBOAT7 rs641738 and NAFLD risks in all genetic models (CC vs. TT: OR = 0.91; CC vs. CT: OR = 0.96; CC vs. CT + TT: OR = 0.95; CC + CT vs. TT: OR = 0.91; C vs. T: OR = 0.99).

CONCLUSION

CC genotype of TM6SF2 rs58542926 was associated with a significantly lower risk of NAFLD, while MBOAT7 rs641738 was not related to NAFLD risks.

Nonalcoholic steatohepatitis: the new frontier for liver transplantation

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is a growing cause of chronic liver disease globally and nonalcoholic steatohepatitis is projected to become the most common indication for liver transplantation. The purpose of this review is to highlight key issues surrounding NAFLD as an indication for liver transplantation, including its increasing prevalence, outcomes related to liver transplantation, development of post liver transplant NAFLD and NAFLD in the liver donor pool.

RECENT FINDINGS

With the advent of direct-acting antiviral therapies, the proportion of patients on the liver transplant list or undergoing liver transplant for chronic hepatitis C infection is steadily decreasing. In contrast, the number transplants performed for NAFLD is increasing. By 2030, it is estimated that the incidence of decompensated cirrhosis and hepatocellular carcinoma will increase by 168 and 137%, respectively, and the number of deaths will increase by 178%.

SUMMARY

Liver transplantation cures cirrhosis but does not treat the underlying metabolic disease associated with NAFLD. Thus, strategies to control comorbidities in patients with NAFLD prior to transplant are needed to decrease waitlist mortality and the recurrence of NAFLD after liver transplant. NAFLD in the donor pool is also a growing concern. Strategies to minimize steatosis and expand the number of donors are critical to meet the growing demand for liver transplantation.

Association between PNPLA3 rs738409 polymorphism and nonalcoholic fatty liver disease (NAFLD) susceptibility and severity: A meta-analysis

OBJECTIVE

This meta-analysis is to investigate the relationship between the patatin-like phospholipase domain containing 3 (PNPLA3) rs738409 polymorphism and the susceptibility and severity of nonalcoholic fatty liver disease (NAFLD).

METHODS

Chinese Journal Full-text Database, Wanfang Database, VIP Database, and PubMed Database were subjected to case-control study retrieving, from January 2008 to December 2014. Following key words were used: fatty liver, PNPLA3, and rs738409 gene or variants or polymorphism or alleles. Meta-analysis was performed based on the retrieved articles.

RESULTS

In total 65 studies were first retrieved according to the key words, and finally 21 studies with 14,266 subjects were included. Meta-analysis showed that PNPLA3 rs738409 polymorphism exerted strong influence not only on fatty liver but also on the histological injury. PNPLA3 rs738409 [G] allele was a risk factor for NAFLD (GG vs CC, OR = 4.01, 95% CI 2.93-5.49; GC vs CC, OR = 1.88, 95% CI 1.58-2.24). PNPLA3 gene variant was significantly associated with the increased serum alanine aminotransferase (ALT) levels (GG vs CC, standardized mean difference  = 0.47, 95% CI 0.14-0.81). In addition, nonalcoholic steatohepatitis (NASH) was more frequently observed in G allele carriers (GG vs CC, OR = 3.24, 95% CI 2.79-3.76; GC vs CC, OR = 2.14, 95% CI 1.43-3.19).

CONCLUSION

PNPLA3 rs738409 polymorphism is not only a factor significantly associated with the susceptibility of NAFLD, but also related to the susceptibility of aggressive diseases.

Donor PNPLA3 rs738409 genotype is a risk factor for graft steatosis. A post-transplant biopsy-based study

BACKGROUND & AIMS

The rs738409 c.444C > G (p.I148M) polymorphism in PNPLA3 is a major factor predisposing to non-alcoholic fatty liver disease. The aim of the study was to clarify the impact of liver and extrahepatic expression of the PNPLA3 p.148M variant on liver graft steatosis after liver transplantation.

METHODS

Fat content was assessed in liver biopsies from 176 transplant recipients. During a period of 4 ± 1 years after transplantation, 17 patients developed grade 3 steatosis, 14 patients grade 2 steatosis, 56 patients grade 1 steatosis, and 89 patients grade 0 steatosis. The influence of the recipient and donor rs738409 genotype and clinical and laboratory data on liver fat content were analyzed using ordinal logistic regression.

RESULTS

The PNPLA3 rs738409 CC/CG/GG genotype frequencies, respectively, were 0.494/0.449/0.057 in the graft donors and 0.545/0.330/0.125 in the graft recipients. In the multivariate analysis, the presence of the PNPLA3 c.444G allele in donor (OR 1.62; 95%CI 1.12-2.33), post-transplant BMI (OR 1.14; 95%CI 1.07-1.22), diabetes mellitus (OR 1.99; 95%CI 1.22-3.22), and serum triglycerides (OR 1.40; 95%CI 1.11-1.76) were independent risk factors for increased liver graft fat content.

CONCLUSIONS

These data indicate that the liver expression of the PNPLA3 p.148M variant confers a genetic predisposition to liver graft steatosis along with nutritional status and diabetes.

Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis in Liver Transplantation

The number of transplants caused by nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NASH) has been progressively increasing and this is expected to become the most common indication for liver transplant in the United States. Patients with NASH show many features of the metabolic syndrome and, as a result, are at higher risk for postoperative cardiovascular morbidity and mortality. Despite this, patients with NASH have long-term graft and patient survival rates comparable with other causes of chronic liver disease. Posttransplant metabolic syndrome is a common occurrence that increases the risk of steatosis in the graft liver.

Effect of PNPLA3 I148M polymorphism on histologically proven non-alcoholic fatty liver disease in liver transplant recipients

AIM

PNPLA3 I148M polymorphism (rs738409 C>G) is the most important and best-known polymorphism for non-alcoholic fatty liver disease (NAFLD). However, little is known about the effect of this polymorphism on NAFLD after liver transplantation (LT). We aimed to evaluate the association between this polymorphism and post-LT NAFLD.

METHODS

We designed a prospective case-control study. Among adult recipients who underwent LT between April 2014 and October 2015, those whose whole blood was preoperatively collected for genotyping in both recipients and coupled donors and those who underwent protocol biopsy at 1 year post-LT were enrolled.

RESULTS

A total of 32 recipients were enrolled. Histologically proven steatosis (≥5%) was present in 28.1% of patients at a mean time of 12.7 ± 2.0 months after LT. Moderate and more severe steatosis (≥33%) was present in 9.4%. One year after LT, steatosis was present in 50.0% of homozygous recipients with the rs738409-G allele. It was present in 27.3% of heterozygous recipients with the rs738409-G allele, and in 9.1% (P = 0.041) of recipients with rs738409-CC. The genotype of the donor was not significantly (P = 0.647) associated with post-LT NAFLD. When both recipient and coupled donor showed heterogeneous or homozygous genotype of the rs738409-G allele, there was significantly more post-LT NAFLD compared to that in others (47.1% vs. 6.7%; P = 0.018). In univariate and multivariate analyses, only the presence of the rs738409-G risk allele in both donor and recipient was a significant risk factor for post-LT NALFD (relative risk, 26.95; P = 0.048).

CONCLUSIONS

PNPLA3 I148M polymorphism can significantly affect histologically proven NAFLD at 1 year post-LT.

De Novo and Recurrence of Nonalcoholic Steatohepatitis After Liver Transplantation

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in developing countries. Approximately 25% of patients with NAFLD develop nonalcoholic steatohepatitis (NASH). NASH-related cirrhosis is now a leading listing indication for liver transplantation in the United States. Although posttransplant survival for NASH-related cirrhosis is comparable with that of other liver diseases, many patients have features of metabolic syndrome, which can contribute to a recurrence of NAFLD or NASH. This article reviews the epidemiology, pathophysiology, and treatment of de novo and recurrence of NASH after liver transplantation.

Liver Transplantation for Alcoholic and Nonalcoholic Fatty Liver Disease: Pretransplant Selection and Posttransplant Management

Alcoholic fatty liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) are common causes of chronic liver disease throughout the world. Although they have similar histologic features, a diagnosis of NAFLD requires the absence of significant alcohol use. ALD is seen commonly in patients with a long-standing history of excessive alcohol use, whereas NAFLD is encountered commonly in patients who have developed complications of obesity, such as insulin resistance, hypertension, and dyslipidemia. Lifestyle contributes to the development and progression of both diseases. Although alcohol abstinence can cause regression of ALD, and weight loss can cause regression of NAFLD, many patients with these diseases develop cirrhosis. ALD and NAFLD account for nearly 30% of liver transplants performed in the United States. Patients receiving liver transplants for ALD or NAFLD have similar survival times as patients receiving transplants for other liver disorders. Although ALD and NAFLD recur frequently after liver transplantation, graft loss from disease recurrence after transplantation is uncommon. Cardiovascular disease and de novo malignancy are leading causes of long-term mortality in liver transplant recipients with ALD or NAFLD.