The interaction between current smoking and hemoglobin on the risk of advanced fibrosis in patients with biopsy-proven nonalcoholic fatty liver disease

Nicotine aggravates liver fibrosis via α7 nicotinic acetylcholine receptor expressed on activated hepatic stellate cells in mice

BACKGROUND

Smoking is a risk factor for liver cirrhosis; however, the underlying mechanisms remain largely unexplored. The α7 nicotinic acetylcholine receptor (α7nAChR) has recently been detected in nonimmune cells possessing immunoregulatory functions. We aimed to verify whether nicotine promotes liver fibrosis via α7nAChR.

METHODS

We used osmotic pumps to administer nicotine and carbon tetrachloride to induce liver fibrosis in wild-type and α7nAChR-deficient mice. The severity of fibrosis was evaluated using Masson trichrome staining, hydroxyproline assays, and real-time PCR for profibrotic genes. Furthermore, we evaluated the cell proliferative capacity and COL1A1 mRNA expression in human HSCs line LX-2 and primary rat HSCs treated with nicotine and an α7nAChR antagonist, methyllycaconitine citrate.

RESULTS

Nicotine exacerbated carbon tetrachloride-induced liver fibrosis in mice (+42.4% in hydroxyproline assay). This effect of nicotine was abolished in α7nAChR-deficient mice, indicating nicotine promotes liver fibrosis via α7nAChR. To confirm the direct involvement of α7nAChRs in liver fibrosis, we investigated the effects of genetic suppression of α7nAChR expression on carbon tetrachloride-induced liver fibrosis without nicotine treatment. Profibrotic gene expression at 1.5 weeks was significantly suppressed in α7nAChR-deficient mice (-83.8% in Acta2, -80.6% in Col1a1, -66.8% in Tgfb1), and collagen content was decreased at 4 weeks (-22.3% in hydroxyproline assay). The in vitro analysis showed α7nAChR expression in activated but not in quiescent HSCs. Treatment of LX-2 cells with nicotine increased COL1A1 expression (+116%) and cell proliferation (+10.9%). These effects were attenuated by methyllycaconitine citrate, indicating the profibrotic effects of nicotine via α7nAChR.

CONCLUSIONS

Nicotine aggravates liver fibrosis induced by other factors by activating α7nAChR on HSCs, thereby increasing their collagen-producing capacity. We suggest the profibrotic effect of nicotine is mediated through α7nAChRs.

Association between Dietary Pattern, Nutritional Status, Metabolic Factors, and Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) can be harmful to the body to varying degrees, and over a prolonged period, patients may develop steatotic cirrhosis or even develop liver cancer based on cirrhosis. Moreover, its harms are related to its severity. Patients with severe steatosis develop hepatocyte destruction, transaminase abnormalities, and long-term progression to steatotic cirrhosis, or even liver cancer, which should be treated aggressively. In order to provide theoretical basis for the prevention and early intervention of NAFLD, we analysis the relationship between nonalcoholic fatty liver disease(NAFLD) and dietary pattern, nutritional status, metabolic factor A total of 517 participants (200 males and 317 females) recruited in this study were gained from the health check center of The Ningbo Seventh Hospital, Ningbo, China, from September 2018 to August 2019. Patients diagnosed with NAFLD were selected as the study subjects. The data on the dietary pattern, nutritional status, and metabolic factors were collected for further analysis. A total of 517 eligible participants (317 females and 200 males) were involved in this study, with a mean age of 54.7 ± 16.7 years. Dessert and fruit diet, healthy dietary pattern, animal food dietary pattern, high salt diet mode, triglyceride, uric acid, adiponectin, and waist-hip ratio were significantly different between the two groups (P < 0.05). Dietary patterns, nutritional status, metabolic factors, and NAFLD are correlated. Furthermore, applying this correlation law can better manage NAFLD patients.

Cigarette smoking and liver diseases

Cigarette smoking is a preventable risk factor for premature morbidity and mortality. A history of smoking is observed in approximately 40% of patients with liver disease, while a growing number of studies are investigating the potential impact of smoking in chronic liver diseases. This review discusses the effects of smoking on liver diseases, at multiple levels, with a focus on its potential causal role. Clinical evidence indicates that cigarette smoking negatively impacts the incidence and severity of fatty liver disease, fibrosis progression, hepatocellular carcinoma development, and the outcomes of patients with advanced liver disease. The underlying mechanisms are complex and involve different pathophysiological pathways including oxidative stress and oncogenic signals. Importantly, smoking promotes cardiovascular disease and extrahepatic cancers in patients with steatohepatitis and in transplant recipients. We discuss how promoting smoking cessation could improve the rates of treatment response (in clinical trials) and fibrosis regression, while reducing the risk of hepatocellular carcinoma and improving liver transplant outcomes. Finally, we discuss current challenges such as the referral of smokers to specialised units for smoking cessation.

Relationship between coffee consumption, sleep duration and smoking status with elastographic parameters of liver steatosis and fibrosis; controlled attenuation parameter and liver stiffness measurements

AIM

our aim was to explore the association between life habits and the controlled attenuation parameter (CAP) and liver stiffness measurements (LSM) as the surrogate markers of liver steatosis and fibrosis in a large cohort of non-alcoholic fatty liver disease (NAFLD) patients.

METHODS

In this prospective, cross-sectional study we had analysed 1998 patients with diagnosed NAFLD. Sleeping duration was categorised in three groups: short (S) (<6 hours), moderate (M) (6-8 hours) and long (L) (>8 hours) sleep duration. Coffee drinking was categorized into no (0), moderate (1-2) and frequent (≥3) consumption (in cups/day). Smoking was categorised as yes versus no.

RESULTS

Frequent coffee consumers had the lowest prevalence of obesity, hypertension, dyslipidaemia and diabetes. Furthermore, coffee non-consumers had highest values of hepatic enzymes, CAP and LSM. Moderate sleep duration was associated with lower values of CAP and LSM. Coffee consumption was associated with lower CAP in all the multivariate models (CAP unadjusted and model 1, 2 and 3), with largest effect in most frequent coffee consumers (≥3, model 3). Also, most frequent coffee consumers were associated with lower LSM in unadjusted model, model 1 and 2, while this was not the case for model 3 and those who consumed 1-2 cups of coffee per day. Reduced sleeping was confirmed as risk factor for elevated CAP in most of the models (unadjusted and model 1 and 2). Also, negative association of LSM was also confirmed in unadjusted model and model 2. Patients which slept 6-8 hours per day were mostly associated with lower CAP and LSM. Smoking status was not associated with CAP or LSM values.

CONCLUSION

Coffee consumption has beneficial effect on CAP and LSM and this effect is dose dependent since and independent of a variety of relevant confounders. We have shown that moderate sleep duration has also beneficial effect on CAP and LSM.