Hepatic steatosis and respiratory diseases: a new panorama

Association of hepatic steatosis and liver fibrosis with chronic obstructive pulmonary disease among adults

With high prevalence and substantial mortality, metabolic dysfunction-associated steatotic liver disease and chronic obstructive pulmonary disease (COPD) are significant public health concerns. Utilizing a large, population-based dataset from the National Health and Nutrition Examination Survey, our study probes the relationship between COPD prevalence and hepatic steatosis and fibrosis, as measured by Vibration-Controlled Transient Elastography. We analyzed data from 693 individuals with COPD and 7229 without. Through weighted multivariate logistic regression analysis, a restricted cubic spline curve, and threshold effect analysis, we investigated the correlation between the severity of hepatic steatosis and fibrosis and the presence of COPD. Our findings revealed a positive correlation between the controlled attenuation parameter (CAP) and COPD prevalence [OR = 1.03 (95% CI 1.01, 1.05)], even after multivariate adjustment. Furthermore, we observed a U-shaped association between CAP and COPD, where the inflection point, CAP value of 264.85 dB/m, corresponded to the lowest COPD prevalence. Our study emphasizes a substantial and complex link between hepatic steatosis and COPD. These findings urge healthcare professionals to factor liver health into COPD management and prompt further exploration into the underlying mechanisms. This could pave the way for the development of improved prevention and treatment strategies.

Serum metabolomic profiling unveils distinct sex-related metabolic patterns in NAFLD

Objective

Obesity poses an increased risk for the onset of Nonalcoholic fatty liver disease (NAFLD). The influence of other factors, such as sex in the incidence and severity of this liver disease has not yet been fully elucidated. Thus, we aimed to identify the NAFLD serum metabolic signatures associated with sex in normal, overweight and obese patients and to associate the metabolite fluctuations across the increasing liver steatosis stages.

Methods and results

Using nuclear magnetic resonance (NMR) serum samples of 210 NAFLD cases and control individuals diagnosed with liver U/S, our untargeted metabolomics enquiry provided a sex distinct metabolic bouquet. Increased levels of alanine, histidine and tyrosine are associated with severity of NAFLD in both men and women. Moreover, higher serum concentrations of valine, aspartic acid and mannose were positively associated with the progression of NAFLD among the male subjects, while a negative association was observed with the levels of creatine, phosphorylcholine and acetic acid. On the other hand, glucose was positively associated with the progression of NAFLD among the female subjects, while levels of threonine were negatively related. Fluctuations in ketone bodies acetoacetate and acetone were also observed among the female subjects probing a significant reduction in the circulatory levels of the former in NAFLD cases. A complex glycine response to hepatic steatosis of the female subjects deserves further investigation.

Conclusion

Results of this study aspire to address the paucity of data on sex differences regarding NAFLD pathogenesis. Targeted circulatory metabolome measurements could be used as diagnostic markers for the distinct stages of NAFLD in each sex and eventually aid in the development of novel sex-related therapeutic options.

Combined with multiplex and network analysis to reveal the key genes and mechanisms of nonalcoholic fatty liver disease

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) has become a significant cause of chronic liver disease in developed countries, as a result of the worldwide trend of obesity and associated metabolic syndrome. Obesity and high-fat diet (HFD) are very common in patients with NAFLD. However, how to screen out key differentially expressed genes (DEGs) is a challenging task. The purpose of this study is to study the screen of key genes and pathways of HFD on the formation process of non-alcoholic fatty liver through network pharmacological analysis.

METHODS

In this study, 173 genes associated with NAFLD were collected from the Gene Expression Omnibus (GEO) database. To find significant genes and pathways, combine network clustering analysis, topology analysis, and pathway analysis.

RESULTS

The results showed that there were four key signaling pathways related to HFD, including complement cascade, Atorvastatin ADME, Asthma and Aflatoxin activation and detoxification. In addition, we identified six representative key genes, including Ccl5, Tlr2, Cd274, Cxcl10, Cxcl9 and Cd74, and screened three intersecting genes in Mus musculus and Homo sapiens sample, including C3, F2 and C7.

CONCLUSIONS

In conclusion, our study constructed the NAFLD gene regulatory network of C57BL/6J mice for the first time and jointly analyzed the Mus musculus samples and Homo sapiens samples. It provides new insights for identifying potential biomarkers and valuable therapeutic clues, and puts forward a new method for web-based research. These findings may provide potential targets for early diagnosis, effective therapy and prognostic markers of NAFLD.

Exercise training attenuates pulmonary inflammation and mitochondrial dysfunction in a mouse model of high-fat high-carbohydrate-induced NAFLD

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) can lead to pulmonary dysfunction that is associated with pulmonary inflammation. Moreover, little is known regarding the therapeutic role of exercise training on pulmonary pathophysiology in NAFLD. The present study aimed to investigate the effect of exercise training on high-fat high-carbohydrate (HFHC)-induced pulmonary dysfunction in C57BL/6 mice.

METHODS

Male C57BL/6 mice (N = 40) were fed a standard Chow (n = 20) or an HFHC (n = 20) diet for 15 weeks. After 8 weeks of dietary treatment, they were further assigned to 4 subgroups for the remaining 7 weeks: Chow (n = 10), Chow plus exercise (Chow+EX, n = 10), HFHC (n = 10), or HFHC plus exercise (HFHC+EX, n = 10). Both Chow+EX and HFHC+EX mice were subjected to treadmill running.

RESULTS

Chronic exposure to the HFHC diet resulted in obesity with hepatic steatosis, impaired glucose tolerance, and elevated liver enzymes. The HFHC significantly increased fibrotic area (p < 0.001), increased the mRNA expression of TNF-α (4.1-fold, p < 0.001), IL-1β (5.0-fold, p < 0.001), col1a1 (8.1-fold, p < 0.001), and Timp1 (6.0-fold, p < 0.001) in the lung tissue. In addition, the HFHC significantly altered mitochondrial function (p < 0.05) along with decreased Mfn1 protein levels (1.8-fold, p < 0.01) and increased Fis1 protein levels (1.9-fold, p < 0.001). However, aerobic exercise training significantly attenuated these pathophysiologies in the lungs in terms of ameliorating inflammatory and fibrogenic effects by enhancing mitochondrial function in lung tissue (p < 0.001).

CONCLUSIONS

The current findings suggest that exercise training has a beneficial effect against pulmonary abnormalities in HFHC-induced NAFLD through improved mitochondrial function.

Greater Muscular Strength Is Associated with a Lower Risk of Pulmonary Dysfunction in Individuals with Non-Alcoholic Fatty Liver Disease

This study investigated the combined effect of handgrip strength (HGS) and non-alcoholic fatty liver disease (NAFLD) on pulmonary function using the Korea National Health and Nutrition Examination Survey (KNHANES) from 2016 to 2018. For the present study, forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), the FEV1/FVC ratio, handgrip strength (HGS) and the hepatic steatosis index (HSI) to estimate NAFLD were obtained from nationwide cross-sectional surveys. For HGS, subjects were divided into higher HGS (upper 50%) and lower HGS (lower 50%). For NAFLD, subjects were divided into the NAFLD cohort (HSI > 36) and the normal cohort (HSI ≤ 36). Of 1651 subjects (men, n = 601), 25.5% of subjects (n = 421) met the HSI > 36. Based on the normal cohort with high HGS, the normal cohort with low HGS showed an increased risk of reduced FVC (OR = 3.062, 95% CI = 2.46−4.83, p < 0.001) and the NAFLD cohort with low HGS showed a further increased risk of reduced FVC (OR = 4.489, 95% CI = 3.43−7.09, p < 0.001). However, the risk of reduced FVC was not significantly increased in NAFLD with high HGS (OR = 1.297, 95% CI = 0.67−2.50, p = 0.436). After adjusted for covariates such as age, sex, smoking, FBG, HDL-C, TG, SBP, DBP, CRP and alcohol consumption, the results remained similar. More importantly, these results were consistent in the obesity-stratified analysis. The current findings of the study suggest that higher muscle strength is associated with a lower risk of reduced pulmonary function in individuals with NAFLD.

Coagulation and Endothelial Dysfunction Associated with NAFLD: Current Status and Therapeutic Implications

Non-alcoholic fatty liver disease (NAFLD) is closely related to insulin resistance, type 2 diabetes mellitus and obesity. It is considered a multisystem disease and there is a strong association with cardiovascular disease and arterial hypertension, which interfere with changes in the coagulation system. Coagulation disorders are common in patients with hepatic impairment and are dependent on the degree of liver damage. Through a review of the literature, we consider and discuss possible disorders in the coagulation cascade and fibrinolysis, endothelial dysfunction and platelet abnormalities in patients with NAFLD.

Preoperative evaluation of geriatric patients undergoing liver transplantation

PURPOSE OF REVIEW

As the population of the world is aging the number of geriatric patients undergoing liver transplantation (LT) is also increasing. They pose a unique challenge for the caregivers, as they have age-related physiological changes, multiple comorbidities and cirrhosis-related pathologies.

RECENT FINDINGS

Twenty-two percent of patients who undergo LT are older than 65 years. Many patients suffer from nonalcoholic steatohepatitis (NASH), hepatocellular carcinoma and hepatitis-C virus. Incidence of NASH tends to increase with age, obesity, diabetes and metabolic syndrome. Elderly patients require comprehensive cognitive, cardiac and pulmonary evaluation prior to LT. Cirrhotic cardiomyopathy, hepatopulmonary syndrome, portopulmonary hypertension and frailty are of specific concern.

SUMMARY

Proportion of elderly patients who are undergoing LT continues to increase. These patients require comprehensive cardiopulmonary and frailty evaluation. Consensus-based practice advisories need to be developed to standardize preoperative evaluation of geriatric patients awaiting LT.

The Troubling Link Between Non-alcoholic Fatty Liver Disease (NAFLD) and Extrahepatic Cancers (EHC)

Non-alcoholic fatty liver disease (NAFLD) is a fast-spreading epidemic across the globe and has serious implications far beyond that of a "benign" liver condition. It is usually an outcome of ectopic fat storage due to chronic positive energy balance leading to obesity and is associated with multiple health problems. While association with cardiovascular disease and hepatocellular cancer is well recognized, it is becoming clear the NAFLD carries with it an increased risk of cancers of extrahepatic tissues. Studies have reported a higher risk for cancers of the colon, breast, prostate, lung, and pancreas. Fatty liver is associated with increased mortality; there is an urgent need to understand that fatty liver is not always benign, and not always associated with obesity. It is, however, a reversible condition and early recognition and intervention can alter its natural history and associated complications.