Caffeine in liver diseases: Pharmacology and toxicology

The effects of caffeine on pancreatic diseases: the known and possible mechanisms

Caffeine, a controversial substance, was once known to be addictive and harmful. In recent years, new effects of caffeine on the human body have been confirmed. Recent research over the past few decades has shown the potential of caffeine in treating pancreas-related diseases. This review aims to analyze the known and possible mechanisms of caffeine on pancreatic diseases and provides an overview of the current research status regarding the correlation between caffeine and pancreatic disease, while enhancing our understanding of their relationship.

Protective Effect of Caffeine and Chlorogenic Acids of Coffee in Liver Disease

Coffee is one of the most widely consumed beverages in the world due to its unique aroma and psychostimulant effects, mainly due to the presence of caffeine. In recent years, experimental evidence has shown that the moderate consumption of coffee (3/4 cups per day) is safe and beneficial to human health, revealing protective effects against numerous chronic metabolic diseases such as diabetes, cardiovascular, neurodegenerative, and hepatic diseases. This review focuses on two of coffee's main bioactive compounds, i.e., caffeine and chlorogenic acids, and their effects on the progression of chronic liver diseases, demonstrating that regular coffee consumption correlates with a lower risk of the development and progression of non-alcoholic steatohepatitis, viral hepatitis, liver cirrhosis, and hepatocellular carcinoma. In particular, this review analyzes caffeine and chlorogenic acid from a pharmacological point of view and explores the molecular mechanism through which these compounds are responsible for the protective role of coffee. Both bioactive compounds, therefore, have antifibrotic effects on hepatic stellate cells and hepatocytes, induce a decrease in connective tissue growth factor, stimulate increased apoptosis with anti-cancer effects, and promote a major inhibition of focal adhesion kinase, actin, and protocollagen synthesis. In conclusion, coffee shows many beneficial effects, and experimental data in favor of coffee consumption in patients with liver diseases are encouraging, but further prospective studies are needed to demonstrate its preventive and therapeutic role in chronic liver diseases.

Exploring Varied Treatment Strategies for Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a liver disorder characterized by steatosis with underlying metabolic risk factors. The prevalence of MASLD continues to rise, leading to increased patient risk of various complications. Recent research has been focused on new therapeutic strategies to reduce the incidence of MASLD and provide effective treatment plans to prevent further irreversible liver damage. The treatment approach is multifactorial, with a primary focus on weight loss and management of underlying comorbidities through lifestyle modifications, pharmacotherapy, or surgical options. Ongoing research is exploring new pharmacological therapies that could enhance the treatment of MASLD.

Quantitative myocardial perfusion in liver transplantation candidates: Poorly metabolized caffeine inhibition of vasodilatory stress

BACKGROUND

Data on cardiac positron emission tomography (PET) in liver transplantation (LT) candidates are limited with no prior study accounting for poorly metabolized caffeine reducing stress perfusion.

METHOD

Consecutive LT candidates (n = 114) undergoing cardiac rest/stress PET were instructed to abstain from caffeine for 2 days extended to 5 and 7 days. Due to persistently high prevalence of measurable blood caffeine after 5-day caffeine abstinence, dipyridamole (n = 41) initially used was changed to dobutamine (n = 73). Associations of absolute flow, coronary flow reserve (CFR), detectable blood caffeine, and Modified End-Stage Liver Disease (MELD) score for liver failure severity were evaluated. Coronary flow data of LT candidates were compared to non-LT control group (n = 102 for dipyridamole, n = 29 for dobutamine).

RESULTS

Prevalence of patients with detectable blood caffeine was 63.3%, 36.7% and 33.3% after 2-, 5- and 7-day of caffeine abstinence, respectively. MELD score was associated with detectable caffeine (odd ratio 1.18,P < 0.001). CFR was higher during dipyridamole stress without-caffeine versus with-caffeine (2.22 ± 0.80 vs 1.55 ± 0.37,P = 0.048) but lower than dobutamine stress (2.22 ± 0.80 vs 2.82 ± 1.02,P = 0.026). Mediation analysis suggested that the dominant association between CFR and MELD score in dipyridamole group derived from caffeine-impaired CFR and liver failure/caffeine interaction. CFR in LT candidates was lower than non-LT control population in both dipyridamole and dobutamine group.

CONCLUSION

We demonstrate exceptionally high prevalence of detectable blood caffeine in LT candidates undergoing stress PET myocardial perfusion imaging resulting in reduced CFR with dipyridamole compared to dobutamine. The delayed caffeine clearance in LT candidates makes dobutamine a preferred stress agent in this population.

Preventive effects of caffeine on nicotine plus high-fat diet-induced hepatic steatosis and gain weight: a possible explanation for why obese smokers with high coffee consumption tend to be leaner

Non-alcoholic fatty liver disease (NAFLD) is a prevalent liver disorder, affecting approximately 25 % of the population. Coffee-drinking obese smokers exhibit lower body weights and decreased NAFLD rates, but the reasons behind this remain unclear. Additionally, the effect of nicotine, the main component of tobacco, on the development of NAFLD is still controversial. Our study aimed to explore the possible reasons that drinking coffee could alleviate NAFLD and gain weight and identify the real role of nicotine in NAFLD of obese smokers. A NAFLD model in mice was induced by administering nicotine and a high-fat diet (HFD). We recorded changes in body weight and daily food intake, measured the weights of the liver and visceral fat, and observed liver and adipose tissue histopathology. Lipid levels, liver function, liver malondialdehyde (MDA), superoxide dismutase (SOD), serum inflammatory cytokine levels and the expression of hepatic genes involved in lipid metabolism were determined. Our results demonstrated that nicotine exacerbated the development of NAFLD and caffeine had a hepatoprotective effect on NAFLD. The administration of caffeine could ameliorate nicotine-plus-HFD-induced NAFLD by reducing lipid accumulation, regulating hepatic lipid metabolism, alleviating oxidative stress, attenuating inflammatory response and restoring hepatic functions. These results might explain why obese smokers with high coffee consumption exhibit the lower incidence rate of NAFLD and tend to be leaner. It is essential to emphasise that the detrimental impact of smoking on health is multifaceted. Smoking cessation remains the sole practical and effective strategy for averting the tobacco-related complications and reducing the risk of mortality.

Inverse association between plasma chlordecone concentrations and progression of alcoholic liver fibrosis: the role of liver metabolism

BACKGROUND AND AIMS

Chlordecone is a persistent organochlorinated insecticide, extensively used in the French West Indies and has been contaminating the population for more than thirty years. Its potentiation effect on hepatotoxic agents has been demonstrated in animal models. We investigated the relationship between environmental exposure to chlordecone and the progression of liver fibrosis.

METHODS

This study included 182 consecutive patients with chronic alcoholic hepatitis whose liver fibrosis was assessed using non-invasive methods. Measured plasma chlordecone concentrations at inclusion were used as surrogate of long-term exposure under steady-state conditions. As the pharmacokinetic processing of chlordecone is largely determined by the liver, we used a human physiologically based pharmacokinetic model to predict plausible changes in the steady-state blood chlordecone concentrations induced by liver fibrosis.

RESULTS

With a median follow-up of 27.1 years after the onset of alcohol consumption, we found a significant decrease in the risk of advanced liver fibrosis with increasing plasma chlordecone concentration (adjusted hazard ratio = 0.56; 95% confidence interval: 0.34-0.95 for the highest vs. lowest tertile, p = 0.04). Changes induced by liver fibrosis influenced the pharmacokinetic processing of chlordecone, resulting in substantial modifications in its steady-state blood concentrations.

CONCLUSION

According to this human model of coexposure to alcohol, reverse causality is the most plausible explanation of this inverse association between plasma chlordecone concentrations and progression of liver fibrosis. This study underlines the importance of considering the pharmacokinetic of environmental contaminants in epidemiological studies when biomarkers of exposure are used to investigate their own impact on the liver.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03373396.

Urinary caffeine and its metabolites in association with advanced liver fibrosis and liver steatosis: a nationwide cross-sectional study

Aim: This study used urinary caffeine and its metabolites to evaluate their relationships with liver steatosis and advanced liver fibrosis. Methods: A total of 2068 adult participants with required data were filtered from the 2009-2014 National Health and Nutrition Examination Survey (NHANES) cycles. Non-invasive scores were applied to define liver steatosis and advanced liver fibrosis. Logistic regression models, weighted quantile sum (WQS) regression models, quantile-based g-computation (QG-Comp) models, and restricted cubic spline (RCS) regression models were used to assess the associations of urinary caffeine and its metabolites with liver steatosis and advanced liver fibrosis. A series of additional analyses were conducted to examine the subgroup-specific differences and test the robustness of the observed results. Results: The major caffeine metabolite mixture and most individual caffeine metabolites were found to be negatively associated with the risk of advanced liver fibrosis with subgroup-specific variations. Only 7-MX consistently showed a negative association with liver steatosis in all analyses, while no association was observed between the major caffeine metabolite mixture and liver steatosis. Conclusion: The major caffeine metabolite mixture and most individual urinary caffeine metabolites exhibited inverse associations with advanced liver fibrosis with subgroup differences. Further prospective and experimental studies are urgently needed to verify our results and further identify the possible mechanisms.

Current therapeutic targets and multifaceted physiological impacts of caffeine

Caffeine, which shares consubstantial structural similarity with purine adenosine, has been demonstrated as a nonselective adenosine receptor antagonist for eliciting most of the biological functions at physiologically relevant dosages. Accumulating evidence supports caffeine's beneficial effects against different disorders, such as total cardiovascular diseases and type 2 diabetes. Conversely, paradoxical effects are also linked to caffeine ingestion in humans including hypertension-hypotension and tachycardia-bradycardia. These observations suggest the association of caffeine action with its ingested concentration and/or concurrent interaction with preferential molecular targets to direct explicit events in the human body. Thus, a coherent analysis of the functional targets of caffeine, relevant to normal physiology, and disease pathophysiology, is required to understand the pharmacology of caffeine. This review provides a broad overview of the experimentally validated targets of caffeine, particularly those of therapeutic interest, and the impacts of caffeine on organ-specific physiology and pathophysiology. Overall, the available empirical and epidemiological evidence supports the dose-dependent functional activities of caffeine and advocates for further studies to get insights into the caffeine-induced changes under specific conditions, such as asthma, DNA repair, and cancer, in view of its therapeutic applications.

Single cell G-protein coupled receptor profiling of activated kidney fibroblasts expressing transcription factor 21

BACKGROUND AND PURPOSE

Activated fibroblasts deposit fibrotic matrix in chronic kidney disease (CKD) and G-protein coupled receptors (GPCRs) are the most druggable therapeutic targets. Here, we set out to establish a transcriptional profile that identifies activated kidney fibroblasts and the GPCRs that they express.

EXPERIMENTAL APPROACH

RNA sequencing and single cell qRT-PCR were performed on mouse kidneys after unilateral ureteral obstruction (UUO). Candidate expression was evaluated in mice with UUO or diabetes or injected with adriamycin or folic acid. Intervention studies were conducted in mice with diabetes or UUO. Correlative histology was performed in human kidney tissue.

KEY RESULTS

Transcription factor 21 (Tcf21)+ cells that expressed 2 or 3 of Postn, Acta2 and Pdgfra were highly enriched for fibrogenic genes and were defined as activated kidney fibroblasts. Tcf21+ α-smooth muscle actin (α-SMA)+ interstitial cells accumulated in kidneys of mice with UUO or diabetes or injected with adriamycin or folic acid, whereas renin-angiotensin system blockade attenuated increases in Tcf21 in diabetic mice. Fifty-six GPCRs were up-regulated in single Tcf21+ kidney fibroblasts, the most up-regulated being Adgra2 and S1pr3. Adenosine receptors, Adora2a/2b, were up-regulated in Tcf21+ fibroblasts and the adenosine receptor antagonist, caffeine decreased Tcf21 upregulation and kidney fibrosis in UUO mice. TCF21, ADGRA2, S1PR3 and ADORA2A/2B were each detectable in α-SMA+ interstitial cells in human kidney samples.

CONCLUSION AND IMPLICATIONS

Tcf21 is a marker of kidney fibroblasts that are enriched for fibrogenic genes in CKD. Further analysis of the GPCRs expressed by these cells may identify new targets for treating CKD.

LINKED ARTICLES

This article is part of a themed issue on Translational Advances in Fibrosis as a Therapeutic Target. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.22/issuetoc.

Coffee, Green Tea Intake, and the Risk of Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis of Observational Studies

Several studies suggest an inverse relationship between coffee intake and risk of hepatocellular carcinoma (HCC), but the association between green tea intake and the risk of HCC is still inconclusive. We performed a meta-analysis of observational studies to clarify the association. We identified eligible studies published from January 1, 1992, to February 28, 2022, by searching PubMed, Web of Science, and EMBASE. A total of 32 studies were included in the meta-analysis. Among them, 21 studies involving 2,492,625 participants and 5980 cases of HCC reported coffee intake, 18 studies involving 1,481,647 participants and 6985 cases of HCC reported green tea intake, and seven studies reported both coffee intake and green tea intake. The results showed that a higher coffee (RR = 0.53; 95% CI: 0.47-0.59; I2 = 0.0%; Pheterogeneity = 0.634) or green tea (RR = 0.80; 95% CI: 0.67-0.95; I2 = 72.30%; Pheterogeneity < 0.001) intake may be associated with a lower risk of HCC. The same results were observed in both cohort and case-control subgroups. Our findings suggest that drinking coffee or green tea may be a potentially effective approach for the prevention or mitigation of HCC, but this still needs to be confirmed by further well-designed observational studies and clinical experimental research.

The Association between Caffeine Intake and the Colonic Mucosa-Associated Gut Microbiota in Humans-A Preliminary Investigation

We examined the association between caffeine and coffee intake and the community composition and structure of colonic microbiota. A total of 34 polyp-free adults donated 97 colonic biopsies. Microbial DNA was sequenced for the 16S rRNA gene V4 region. The amplicon sequence variant was assigned using DADA2 and SILVA. Food consumption was ascertained using a food frequency questionnaire. We compared the relative abundance of taxonomies by low (<82.9 mg) vs. high (≥82.9 mg) caffeine intake and by never or <2 cups vs. 2 cups vs. ≥3 cups coffee intake. False discovery rate-adjusted p values (q values) <0.05 indicated statistical significance. Multivariable negative binomial regression models were used to estimate the incidence rate ratio and its 95% confidence interval of having a non-zero count of certain bacteria by intake level. Higher caffeine and coffee intake was related to higher alpha diversity (Shannon index p < 0.001), higher relative abundance of Faecalibacterium and Alistipes, and lower relative abundance of Erysipelatoclostridium (q values < 0.05). After adjustment of vitamin B2 in multivariate analysis, the significant inverse association between Erysipelatoclostridium count and caffeine intake remained statistically significant. Our preliminary study could not evaluate other prebiotics in coffee.