Cytokine gene polymorphisms in heavy drinkers with and without decompensated liver disease: a case-control study

Interleukin-6 gene polymorphisms and susceptibility to liver diseases: A meta-analysis

BACKGROUND

Several studies have explored the associations between interleukin-6 (IL-6) gene polymorphisms and the susceptibility to liver diseases, however, results remain ambiguous. The goal of this study was to conduct a meta-analysis to provide more credible evidence.

METHODS

Studies identified in the PubMed, Cochrane Library, and EMBASE databases were used to perform a meta-analysis via the STATA software. Pooled odds ratios (OR) were calculated under fixed- and random-effects models to estimate the potential genetic associations.

RESULTS

Twenty-five case-control studies involving 5813 cases and 5298 controls were included in this meta-analysis. Overall, the pooled results suggested that rs1800795 polymorphism was significantly associated with the risk of liver diseases in heterozygote (GC vs CC; OR = 1.57) and dominant (GG+GC vs CC: OR = 1.47) models; rs1800796 polymorphism was significantly associated with the susceptibility to liver diseases in heterozygote (GG vs GC; OR = 0.58) and recessive (GG vs GC+CC: OR = 0.68) models; rs1800797 polymorphism was significantly associated with genetic predisposition to liver diseases in homozygote (GG vs AA: OR = 1.63), heterozygote (GA vs AA; OR = 1.53) and dominant (GG + GA vs AA: OR = 1.61) models. A similar conclusion was found in the HBV, HCV, HCC, NASH and alcoholic liver disease of all ethnic populations for rs1800795; HBV and Asian subgroups for rs1800796; HCV and non-Asian subgroups for rs1800797. However, IL-6 rs2069837 and rs2066992 polymorphisms did not exhibit significant associations with the risk of liver diseases under any genetic models.

CONCLUSION

This meta-analysis suggests that patients carrying G (rs1800795), C (rs1800796) or G (rs1800797) allele or genotypes of IL-6 may be more likely to suffer from liver diseases, which was ethnic-dependent.

Network Pharmacology Databases for Traditional Chinese Medicine: Review and Assessment

The research field of systems biology has greatly advanced and, as a result, the concept of network pharmacology has been developed. This advancement, in turn, has shifted the paradigm from a “one-target, one-drug” mode to a “network-target, multiple-component-therapeutics” mode. Network pharmacology is more effective for establishing a “compound-protein/gene-disease” network and revealing the regulation principles of small molecules in a high-throughput manner. This approach makes it very powerful for the analysis of drug combinations, especially Traditional Chinese Medicine (TCM) preparations. In this work, we first summarized the databases and tools currently used for TCM research. Second, we focused on several representative applications of network pharmacology for TCM research, including studies on TCM compatibility, TCM target prediction, and TCM network toxicology research. Third, we compared the general statistics of several current TCM databases and evaluated and compared the search results of these databases based on 10 famous herbs. In summary, network pharmacology is a rational approach for TCM studies, and with the development of TCM research, powerful and comprehensive TCM databases have emerged but need further improvements. Additionally, given that several diseases could be treated by TCMs, with the mediation of gut microbiota, future studies should focus on both the microbiome and TCMs to better understand and treat microbiome-related diseases.

Constitutional and functional genetics of human alcohol-related hepatocellular carcinoma

Exploration of the constitutional genetics of hepatocellular carcinoma (HCC) has identified numerous variants associated with a higher risk of liver cancer in alcoholic cirrhotic patients. Although Genome-Wide Association studies have not been carried out in the field of alcohol-related HCC, common single nucleotide polymorphisms conferring a small increase in the risk of liver cancer risk have been identified and shown to modulate ethanol metabolism, inflammation, oxidative stress, iron or lipid metabolism. Specific patterns of gene mutations including CTNNB1, TERT, ARID1A and SMARCA2 exist in alcohol-related HCC. Moreover, a specific mutational process observed at the nucleotide level by next generation sequencing has revealed cooperation between alcohol and tobacco in the development of HCC. Combining this genetic information with epidemiological and clinical data that might define specific HCC risk classes and refine surveillance strategies needs to be assessed in large prospective cohorts of patients with alcoholic cirrhosis.

Polymorphisms in the IL-1 gene cluster influence systemic inflammation in patients at risk for acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) in cirrhosis is an increasingly recognized syndrome characterized by acute decompensation, organ failure(s) and high short-term mortality. Recent findings suggest that an overexuberant systemic inflammation plays a primary role in ACLF progression. In this study, we examined whether genetic factors shape systemic immune responses in patients with decompensated cirrhosis. Six single-nucleotide polymorphisms (SNPs) in inflammation-related genes (interleukin [IL]-1 beta [IL-1β], rs1143623; IL-1 receptor antagonist [IL-1ra], rs4251961; IL-10, rs1800871; suppressor of cytokine signaling-3, rs4969170; nucleotide-binding oligomerization domain-containing protein 2, rs3135500; and chemerin chemokine-like receptor 1, rs1878022) were genotyped in 279 patients with cirrhosis with (n = 178) and without (n = 101) ACLF from the CANONIC study of the CLIF consortium. Among these SNPs, we identified two polymorphisms belonging to the IL-1 gene cluster (IL-1β and IL-1ra) in strong association with ACLF. Both SNPs were protective against ACLF; IL-1β (odds ratio [OR], 0.34, 95% confidence interval [CI], 0.13-0.89; P < 0.05) and IL-1ra (OR, 0.58; 95% CI, 0.35-0.95; P < 0.05) under the recessive and overdominant inheritance models, respectively. These protective SNPs translated into reduced circulating levels of IL-1β, IL-1α, IL-6, granulocyte-colony stimulating factor, granulocyte-macrophage colony-stimulating factor, and C-reactive protein at enrollment as well as after 7-14 days of admission. These findings were confirmed in vitro in leukocytes incubated with plasma from patients with decompensated cirrhosis carrying the protective SNP genotypes. Notably, a higher frequency of the protective genotypes was observed in patients without (80%) than in those with (20%) ACLF. Consistently, patients carrying the combined protective genotypes showed a lower 28-day mortality rate.

CONCLUSION

These data identify two common functional polymorphisms in the IL-1 gene cluster, which are associated with the inflammatory process related to development of ACLF. (Hepatology 2017;65:202-216).

Associations between the tumor necrosis factor-α gene and interleukin-10 gene polymorphisms and risk of alcoholic liver disease: A meta-analysis

BACKGROUND

The critical roles of tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) in the pathogenesis of alcoholic liver diseases (ALD) suggest that functional variations in the TNF-α (TNFA) and IL-10 genes may be related to individual susceptibility to ALD. As available studies examining the associations between TNFA or IL-10 polymorphisms and ALD risk have yielded conflicting results, a meta-analysis was conducted to clarify the potential relation between TNFA and IL-10 polymorphisms and the risk of ALD.

METHODS

A comprehensive literature search was conducted to identify relevant studies. Pooled odds ratios and 95% confidence intervals were calculated using a random-effects model. The heterogeneity between studies was assessed using the Cochran's Q statistic and the I(2) statistic. Publication bias was assessed using funnel plots and the Egger's regression test.

RESULTS

A total of 17studies and 12studies were identified and included in the meta-analysis of the associations between TNFA polymorphisms and ALD risk, and IL-10 polymorphisms and ALD risk, respectively. The pooled results showed that the "A" allele of the TNFA-238G>A polymorphism was significantly associated with an increased risk of ALD. Significant differences in the allele and genotype distributions of the IL-10-1082A>G polymorphism were detected in the comparison between ALD patients and healthy controls, but not when comparing ALD patients and alcohol dependent individuals without ALD. No significant associations between other polymorphic loci and ALD risks were detected.

CONCLUSIONS

The TNFA-238G>A polymorphism was significantly associated with ALD risk, while the TNFA-308G>A polymorphism and IL-10 polymorphisms (-1082A>G and -592C>A) may not be associated with the individual susceptibility to ALD. The impact of combined TNFA and IL-10 polymorphisms on individual susceptibility to ALD needs to be investigated in future studies.

Genetic risk markers for hepatocellular carcinoma in patients with alcoholic liver disease

Various single nucleotide polymorphisms have been reported to be associated with a higher risk of hepatocellular carcinoma in alcoholic cirrhotic patients. Until now, only common variants conferring a small increase in liver cancer risk have been identified. These inherited factors are able to modulate several biological pathways involved in alcohol-induced hepatocarcinogenesis, such as ethanol metabolism, inflammation, oxidative stress, or iron and lipid homeostasis. How the combination of these variants might collectively define an individual genomic risk prediction is currently being investigated. The other challenge in clinical practice lies in defining how to integrate this genetic information with other clinical parameters so as to refine selection of alcoholic cirrhotic patients according to various classes of hepatocellular carcinoma risk.

Polymorphisms of the CD14 genes are associated with susceptibility to alcoholic liver disease in Greek patients

BACKGROUND

The incidence and severity of alcoholic liver disease (ALD) in chronic drinkers has been found to correlate with some environmental factors and especially with the dose of alcohol consumption, but it is obvious that other parameters clearly contribute to individual alcohol susceptibility. Chronic ethanol exposure leads to continuous endotoxin-mediated Toll-like receptor-4 (TLR-4) and CD14 activation and subsequent cytokine release resulting in chronic inflammation with continued hepatocellular damage. Therefore, genetic studies of polymorphism in TLR-4 and CD14 genes seem to be appropriate in determining genetic susceptibility to ALD. Our aim is to evaluate in a series of Greek drinkers, the possible association of polymorphisms in the TLR-4 and CD14 genes with ALD.

METHODS

In 96 patients with ALD polymorphism of TLR-4 and CD14 genes were studied compared with 104 patients with cirrhosis of other etiology, 100 healthy subjects, and 50 patients with a history of alcohol abuse but without liver disease.

RESULTS

No association between ALD and the presence of the Asp299Gly and Thr399Ile polymorphisms in the TLR-4 gene could be documented in our patients. Regarding the CD14 -159 (C/T) genotypes, TT genotype and T allele were found to be overrepresented in alcoholic patients compared with patients with nonalcohol-induced liver disease and healthy controls. On the other side, when compared patients with ALD and patients with alcohol abuse and no liver disease, TT genotype was found to be significantly less frequent. There is no statistically significant association with the presence of the T allele and the severity of ALD, suggesting that CD14 polymorphism does not influence disease severity in advanced stages of the disease.

CONCLUSIONS

In our series in Greek patients with alcohol abuse and alcoholic cirrhosis, a significant negative association with the CD14 endotoxin receptor gene polymorphism (TT genotype) but not with the TLR-4 gene polymorphism was documented.

Familial predisposition to alcoholic liver disease: a case-control study

OBJECTIVES

The variable susceptibility to alcoholic liver disease (ALD) may be genetic in origin, but clear candidate genes have not yet emerged. This study aimed to assess familial clustering of ALD using a case-control strategy.

METHODS

We recruited two cohorts of heavy drinkers (>60 U/week for men or >40 U/week for women): 291 individuals with decompensated ALD (Child's grade B or C) and 208 controls with similar alcohol consumption but no evidence of liver disease. Data were collected, through a questionnaire and a follow-up telephone call, on drinking behaviour and the presence of liver disease in parents and siblings of cases and controls. The results in the relatives of cases were compared with those in the relatives of the controls.

RESULTS

The odds ratio (OR) of heavy drinking in the relatives of the cases compared with the controls was 0.91 [95% confidence interval (CI), 0.73-1.1]. OR in the relatives of the cases versus the controls was 1.27 for definite ALD (95% CI, 0.63-2.6), 1.09 for all ALD (95% CI, 0.58-2.0) and 1.0 for all liver diseases (95% CI, 0.60-1.7). Multiple subgroup analyses yielded similar OR values, not exceeding 1.5.

CONCLUSION

These data do not suggest a strong familial predisposition to the development of ALD and rather suggest that the main cofactors are environmental.

Association of inflammation genes with alcohol dependence/abuse: a systematic review and a meta-analysis

The aim of the present work was to systematically review all association studies of inflammation genes with alcohol dependence/alcohol abuse (AD/AA) and to perform a meta-analysis. Odds ratios (ORs) were estimated by contrasting the ratio of counts of the 'high-risk' versus 'low-risk' alleles in AD/AA cases versus controls. Data reported in at least three published studies were available for four genetic polymorphisms [TNF-α-238 (rs361525, G/A); TNF-α-308 (rs1800629, G/A); IL-1RA (VNTR [86 bp]n); IL-10-592 (rs1800896, C/A)]. In total, nine meta-analyses were performed. Of these, only the TNF-α-238 polymorphism showed a significant association with AD/AA (OR=1.36, 95% CI: 1.05-1.76). This risk remained significant and increased slightly when we considered only patients with advanced alcohol-related liver disease (AALD) (OR=1.5, 95% CI: 1.13-1.98) but not when we considered only patients without AALD (OR=1.08, 95% CI: 0.5-2.35). Sensitivity analysis showed that this genetic association is derived from the AALD phenotype rather than from AD. Our approach is limited by our phenotype definition; some studies included chronic heavy drinkers (minimal daily consumption of 80 g for a minimal duration of 10 years) but without a standardized psychiatric assessment.

Polymorphisms in the interleukin-10 gene promoter and the risk of alcoholism and alcoholic liver disease in Caucasian Spaniard men

Controversy surrounds the possible influence of the single nucleotide polymorphisms (SNPs) of the interleukin-10 (IL-10) gene promoter on the risk for alcoholic liver disease. Our aim was to determine whether the SNP of the IL-10 gene promoter are associated with an increased risk for alcoholism and for alcoholic liver disease in male Spaniards. The -627 C>A SNP of the IL-10 gene promoter was assessed in a cohort of 344 Caucasian Spanish men, 168 alcoholics, and 176 nonalcoholics. The alcoholic group comprised 79 individuals without liver histopathologic abnormalities and 89 patients with chronic alcoholic liver disease. The nonalcoholic group was made of 62 healthy controls and 114 patients with chronic nonalcoholic liver disease. Genotyping was performed using PCR and automatic sequencing analysis methods on white cell DNA. Genotype and allele frequencies were compared by using the chi(2) test. Overall, no differences in either genotype and allele distribution was observed when comparing the four patient categories defined (P=0.62 and P=0.33, respectively). Subset analyses showed no differences in the genotype and allele distributions between all alcoholic and all nonalcoholic subjects (P=0.55 and P=0.29, respectively). This study failed to detect significant associations of the IL-10 -627C>A SNP and alcoholism or alcoholic liver disease in a cohort of Caucasian male Spaniards.

Genetic polymorphisms in non-alcoholic fatty liver disease: interleukin-6-174G/C polymorphism is associated with non-alcoholic steatohepatitis

BACKGROUND

Environmental and genetic factors play a role in the pathogenesis and natural history of non-alcoholic fatty liver disease (NAFLD).

METHODS

In 114 subjects with NAFLD we report the prevalence and correlation with clinical parameters of three polymorphisms: interleukin-6 (-174G/C), plasma cell differentiation antigen (K121Q) and microsomal transfer protein (-493G/T). In 59 biopsied patients with NAFLD the polymorphisms were also related to histological features.

RESULTS

IL-6 -174C variant was more prevalent (p<0.01) in NAFLD compared to controls. In the NAFLD group, C carriers had higher HOMA-IR and fasting insulin than G carriers (p<0.05). The prevalence of IL-6/C variant was higher (83%) in biopsied than in not biopsied subjects (66%) (p<0.05). In biopsied subjects, C carriers had higher HOMA and fasting insulin (p<0.05) compared than those with G allele. The prevalence of IL-6 -174G/C polymorphism was significantly higher in NASH than in NAFLD (p=0.048). At logistic regression analysis IL-6 -174C was an independent predictor of both NAFLD (OR 4.116, C.I. 1.126-15.048) and NASH (OR 7.035, C.I. 1.167-42.394). Conversely, the distribution of PC-1 and MTP polymorphisms was not significantly different compared to the control group, nor associated with clinical or histological characteristics.

CONCLUSIONS

Our data suggest that IL-6 -174C genetic polymorphisms, involved in inflammation and insulin resistance, are associated with NASH. These data may contribute to the understanding of the genetic susceptibility to NAFLD.

Tumor necrosis factor polymorphisms and alcoholic liver disease: a HuGE review and meta-analysis

The association between alcoholic liver disease (ALD) and tumor necrosis factor-alpha gene (TNFA) polymorphisms has been analyzed in several studies, but results have been conflicting. The main purpose of this study was to integrate previous findings and explore whether these polymorphisms are associated with susceptibility to ALD. The authors surveyed studies on the relation between TNFA gene polymorphisms and ALD by means of an electronic database search. A meta-analysis was conducted in a random-effects model. The association between ALD and the -238G>A or -308G>A polymorphism of the TNFA gene has been analyzed in 11 studies. Concerning the -238G>A polymorphism, the authors found a significant association between possession of the A allele and risk of alcoholic liver cirrhosis (odds ratio = 1.47, 95% confidence interval: 1.05, 2.07). Meta-analysis of the relation between the -308G>A polymorphism and ALD did not show any significant association. Given the limited number of studies and the potential biases, more data are needed to confirm the association described for the -238A allele.

Polymorphisms of the IL-1 gene complex are associated with alcohol dependence in Spanish Caucasians: data from an association study

BACKGROUND

There is growing evidence for involvement of pro-inflammatory cytokines in alcohol dependence. The aim of this study was to investigate whether 4 functionally relevant polymorphisms of the interleukin-1 (IL-1) and tumor necrosis factor-alpha genes were associated with alcohol dependence and with measures of clinical severity and treatment outcome.

METHODS

Two hundred alcohol-dependent (AD) patients and 420 healthy controls from the same Spanish Caucasian population were genotyped using standard methods. Baseline and 6-month assessments included alcohol intake, addiction severity, and biomarkers of alcohol intake.

RESULTS

Alcohol-dependent patients showed an excess of IL-1alpha-889 C/T [50.8% vs. 39.3%, chi(2) (df) = 7.30 (2), uncorrected p = 0.026, corrected p = 0.104] and IL-1RA (86 bp)(n) A1/A1 genotypes [64.8% vs. 50.8%, chi(2) (df) = 12.65 (3), corrected p = 0.020]. The A1/A1 excess was associated with alcohol dependence only in men [69.9% vs. 49.5%, chi(2) (df) = 15.72 (2), corrected p < 0.001]. Six-month clinical and hematological outcome measures did not vary by genotype of the 4 polymorphisms. Haplotype analysis revealed an excess of the IL-1alpha-889 C/IL-1beta +3953 C/IL-1RA A2 haplotype in the control group compared with AD patients [20.0% vs. 14.1%, chi(2) (df) = 7.25 (1), p = 0.007; odds ratio (OR) = 0.64, 95% confidence interval (CI) = 0.46-0.89] and in the abstainers after 6 months of treatment compared with nonabstinent patients [14.7% vs. 6.2%, chi(2) (df) = 5.65 (1), p = 0.017; OR = 2.56, 95% CI = 1.15-5.62].

CONCLUSIONS

Our findings provide further tentative evidence of the role of IL-1 in alcohol dependence as well as evidence that the nature of the associations may be direct, gender-specific, or involve haplotype effects. However, findings from single association studies constitute tentative knowledge and must be interpreted carefully and precise replication is required.