Genetic predisposition, lifestyle risk, and obesity associate with the progression of nonalcoholic fatty liver disease

Sleep Pattern, Genetic Susceptibility, and Abdominal Aortic Aneurysm in UK Biobank Participants: Large-Scale Cohort Study

Background

Abdominal aortic aneurysm (AAA) is an important cause of cardiovascular mortality.

Objectives

The authors aimed to explore the associations between sleep patterns and genetic susceptibility to AAA.

Methods

We included 344,855 UK Biobank study participants free of AAA at baseline. A sleep pattern was defined by chronotype, sleep duration, insomnia, snoring, and daytime sleepiness, and an overall sleep score was constructed with a range from 0 to 5, where a high score denotes a healthy sleep pattern. Polygenic risk score based on 22 single nucleotide polymorphisms was categorized into tertiles and used to evaluate the genetic risk for AAA. Cox proportional hazards regression models were used to assess the association between sleep, genetic factors, and the incidence of AAA.

Results

During a median of 12.59 years of follow-up, 1,622 incident AAA cases were identified. The HR per 1-point increase in the sleep score was 0.91 (95% CI: 0.86-0.96) for AAA. Unhealthy sleep patterns, defined as a sleep score ranging from 0 to 3, were found to be associated with a higher risk of AAA for the intermediate (HR: 1.18, 95% CI: 1.06-1.31) and poor sleep patterns (HR: 1.40, 95% CI: 1.13-1.73), respectively, compared to the healthy pattern. Participants with poor sleep patterns and high genetic risks had a 2.5-fold higher risk of AAA than those with healthy sleep patterns and low genetic risk.

Conclusions

In this large prospective study, healthy sleep patterns were associated with a lower risk of AAA among participants with low, intermediate, or high genetic risk.

Navigating nonalcoholic fatty liver disease (NAFLD): Exploring the roles of estrogens, pharmacological and medical interventions, and life style

The pursuit of studying this subject is driven by the urgency to address the increasing global prevalence of Non-Alcoholic Fatty Liver Disease (NAFLD) and its profound health implications. NAFLD represents a significant public health concern due to its association with metabolic disorders, cardiovascular complications, and the potential progression to more severe conditions like non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Liver estrogen signaling is important for maintaining liver function, and loss of estrogens increases the likelihood of NAFLD in postmenopausal women. Understanding the multifaceted mechanisms underlying NAFLD pathogenesis, its varied treatment strategies, and their effectiveness is crucial for devising comprehensive and targeted interventions. By unraveling the intricate interplay between genetics, lifestyle, hormonal regulation, and gut microbiota, we can unlock insights into risk stratification, early detection, and personalized therapeutic approaches. Furthermore, investigating the emerging pharmaceutical interventions and dietary modifications offers the potential to revolutionize disease management. This review reinforces the role of collaboration in refining NAFLD comprehension, unveiling novel therapeutic pathways, and ultimately improving patient outcomes for this intricate hepatic condition.

Dietary Inflammatory Potential, Inflammation-Related Lifestyle Factors, and Incident Anxiety Disorders: A Prospective Cohort Study

It is unclear whether diet-associated inflammation is related to the development of anxiety disorders. We aimed to investigate the association between energy-adjusted dietary inflammatory index (E-DII) scores and the incidence of anxiety disorders, and explore the joint effects of E-DII scores with other inflammatory lifestyles in enhancing anxiety risk. In the UK Biobank Study of 96,679 participants, baseline E-DII scores were calculated from the average intake of at least two 24 h dietary recalls. Multivariable-adjusted Cox models were used to evaluate the associations between E-DII scores and the incidence of total anxiety disorders, and primary types and subtypes; additive and multiplicative interactions of a pro-inflammatory diet and seven inflammatory lifestyles were examined. After a median follow-up of 9.4 years, 2785 incident cases of anxiety disorders occurred. Consuming a pro-inflammatory diet was significantly associated with a higher risk of total anxiety disorders (HRQ4vsQ1 = 1.12, 95% CI = 1.00-1.25), and positive associations were consistently identified for primary types and subtypes of anxiety disorders, with HRs ranging from 1.08 to 1.52, and were present in women only. Both additive and multiplicative interactions of current smoking and a proinflammatory diet on total anxiety risk were identified. A proinflammatory diet was associated with a higher incidence of anxiety disorders, and current smoking may synergize with a proinflammatory diet to promote anxiety risk, particularly among women.

A healthy lifestyle, Life's Essential 8 scores and new-onset severe NAFLD: A prospective analysis in UK Biobank

BACKGROUND

The association of a healthy lifestyle and the American Heart Association (AHA) Life's Essential 8 (LE8) score with the risk of new-onset nonalcoholic fatty liver disease (NAFLD) remains uncertain. We aimed to explore the associations between a healthy lifestyle and higher LE8 scores with new-onset severe NAFLD in the general population.

METHODS

266,645 participants without prior liver diseases were included from the UK Biobank. A healthy lifestyle was determined based on body mass index, smoking, alcohol consumption, physical activity, sleep duration, and diet. LE8 score was generated from 8 metrics according to the AHA cardiovascular health (CVH) advisory, varying from 0 to 100 scores. The primary study outcome was new-onset severe NAFLD. The study outcomes were ascertained by hospital inpatient data, cancer registry, and death register records.

RESULTS

During a median follow-up of 11.9 years, 2284(0.9 %) participants developed severe NAFLD. Compared with those with a poor lifestyle, participants with intermediate (HR, 0.60; 95%CI: 0.55-0.67), or ideal (HR, 0.20; 95%CI: 0.15-0.27) lifestyles had a significantly lower risk of new-onset severe NAFLD. Compared to the low CVH group (LE8 scores: 0-49), the moderate (scores:50-79) (HR, 0.43; 95%CI: 0.39-0.48) and high CVH (scores:80-100) (HR, 0.10; 95%CI: 0.07-0.14) group had a significantly lower risk of new-onset severe NAFLD. Accordingly, adhering to a healthy lifestyle and attaining a high CVH in all individuals could prevent 66.8 % (95%CI: 58.5-75.1 %) and 77.3 % (95%CI:70.4-84.2 %) of severe NAFLD, respectively. Genetic risks of NAFLD did not modify these associations.

CONCLUSION

A favorable lifestyle and a higher LE8 score were significantly associated with a lower risk of new-onset severe NAFLD, independent of genetic risks of NAFLD.

Characteristics and long-term mortality of patients with non-MAFLD hepatic steatosis

BACKGROUND & AIMS

A cluster of hepatic steatosis without metabolic abnormalities has been excluded by the MAFLD definition, referred to as non-MAFLD steatosis. We aimed to characterize the non-MAFLD steatosis.

METHODS

We included 16,308 individuals from the UK Biobank who had magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) to describe the clinical and genetic features of non-MAFLD steatosis in a cross-sectional design, and 14,797 individuals of the NHANES III who underwent abdominal ultrasonography at baseline to assess the long-term mortality of non-MAFLD steatosis in a prospective cohort design.

RESULTS

Of 16,308 individuals in the UK Biobank, 2747 fatty liver disease (FLD) cases (2604 MAFLD and 143 non-MAFLD) and 3007 healthy controls (without metabolic dysfunctions) were identified. The mean PDFF (10.65 vs. 9.00) and the proportion of advanced fibrosis (fibrosis-4 index > 2.67, 1.27% vs. 1.40%) were comparable between MAFLD and non-MAFLD steatosis. Non-MAFLD steatosis has the highest minor allele frequency of PNPLA3 rs738409, TM6SF2 rs58542926, and GCKR rs1260326 in contrast to the other two groups. The genetic risk score calculated by PNPLA3, TM6SF2, and GCKR has a certain predictive ability for non-MAFLD steatosis (AUROC = 0.69). NHANES III population showed that compared to healthy individuals, the adjusted hazard ratio of non-MAFLD steatosis increased by 1.52 (95% confidence interval: 1.21-1.91) and 1.78 (95% confidence interval: 1.03-3.07) for all-cause and heart disease-related mortality, respectively.

CONCLUSIONS

Non-MAFLD steatosis has comparable degrees of hepatic steatosis and fibrosis to MAFLD and increases the risk of mortality. Genetic predisposition highly contributes to the risk of non-MAFLD steatosis.

Attribution of diabetes to the development of severe liver disease in the general population

BACKGROUND AND AIMS

Diabetes is associated with advanced liver disease and predicts mortality regardless of the primary aetiology of the liver disease. Even a family history of diabetes has been linked to advanced liver fibrosis in non-alcoholic fatty liver disease (NAFLD). However, the fraction of liver-related outcomes in the general population that are attributable to diabetes remains unclear.

METHODS

The population attributable fraction (PAF) of diabetes for liver disease as a time-dependent exposure was estimated in the Finnish FINRISK study (n = 28 787) and the British Whitehall II study (n = 7855). We also assessed the predictive ability of a family history of diabetes for liver-related outcomes. Incident diabetes data were from drug purchase/reimbursement and healthcare registries (FINRISK) or follow-up examinations (Whitehall II). Incident severe liver outcomes were identified through linkage with national healthcare registries.

RESULTS

Diabetes was associated with a two-fold risk of liver-related outcomes in both the FINRISK (HR, 1.92; p < .001) and Whitehall II (HR, 2.37; p < .001) cohorts, and this remained significant after adjusting for multiple confounders. PAF analyses demonstrated that diabetes explained 12-14% of the risk for severe liver-related outcomes after 10 and 20 years of follow-up. Also, maternal diabetes increased the risk of liver-related outcomes in the FINRISK (HR, 1.43; p = .044) and Whitehall II (HR, 2.04; p = .051) cohorts.

CONCLUSION

Approximately 12%-14% of severe liver-related outcomes are attributable to diabetes at the population level. The association between maternal diabetes and liver disease might suggest a mitochondrial genetic mechanism.

Non-alcoholic fatty liver is associated with increased risk of irritable bowel syndrome: a prospective cohort study

BACKGROUND

The relationship between non-alcoholic fatty liver degree as well as non-alcoholic fatty liver disease (NAFLD) and irritable bowel syndrome (IBS) remains poorly understood. We aimed to investigate the prospective association of non-alcoholic fatty liver degree as well as NAFLD with incident IBS in a large-scale population-based cohort.

METHODS

Participants free of IBS, coeliac disease, inflammatory bowel disease, alcoholic liver disease, and any cancer at baseline from the UK Biobank were included. Non-alcoholic fatty liver degree was measured by a well-validated fatty liver index (FLI), with FLI ≥ 60 as an indicator of NAFLD. Primary outcome was incident IBS. Cox proportional hazard model was used to investigate the associated risk of incident IBS.

RESULTS

Among 396,838 participants (mean FLI was 48.29 ± 30.07), 153,203(38.6%) were with NAFLD diagnosis at baseline. During a median of 12.4-year follow-up, 7129 cases of incident IBS were identified. Compared with non-NAFLD, NAFLD patients showed a 13% higher risk of developing IBS (HR = 1.13, 95%CI: 1.05-1.17) after multivariable adjustment. Compared with the lowest, the highest FLI quartile was associated with a significantly increased risk of IBS (HR_{Q4 VS Q1} = 1.21, 1.13-1.30, P_trend < 0.001). Specifically, the positive association between non-alcoholic fatty liver degree and IBS was also observed by per SD change of FLI (adjusted HR = 1.08, 1.05-1.10). Further sensitivity analysis and subgroup analysis indicated similar results, with the positive association particularly observed in females, but not in males.

CONCLUSIONS

High degree of non-alcoholic fatty liver as well as non-alcoholic fatty liver disease is associated with increased risk of incident IBS. Further studies are warranted to confirm the findings and elucidate the underlying biological mechanisms.

Developmental modeling of hepatogenesis using obese iPSCs-hepatocyte differentiation uncovers pathological features

Obesity is a multigene disorder. However, in addition to genetic factors, environmental determinants also participate in developing obesity and related pathologies. Thus, obesity could be best described as a combination of genetic and environmental perturbations often having its origin during the early developmental period. Environmental factors such as energy-dense food and sedentary lifestyle are known to be associated with obesogenicity. However, the combinatorial effects of gene-environment interactions are not well understood. Understanding the role of multiple genetic variations leading to subtle gene expression changes is not practically possible in monogenic or high-fat-fed animal models of obesity. In contrast, human induced pluripotent stem cells (hiPSCs) from individuals with familial obesity or an obesogenic genotype could serve as a good model system. Herein, we have used hiPSCs generated from normal and genetically obese subjects and differentiated them into hepatocytes in cell culture. We show that hepatocytes from obese iPSCs store more lipids and show increased cell death than normal iPSCs. Whole transcriptome analyses in both normal and obese iPSCs treated with palmitate compared to control revealed LXR-RXR and hepatic fibrosis pathways were enriched among other pathways in obese iPSCs compared to normal iPSCs. Among other genes, increased CD36 and CAV1 expression and decreased expression of CES1 in obese iPSCs could have been responsible for excess lipid accumulation, resulting in differential expression of genes associated with hepatic fibrosis, a key feature of non-alcoholic fatty liver disease (NAFLD). Our results demonstrate that iPSCs derived from genetically obese subjects could serve as an excellent model to understand the effects of this multigene disorder on organ development and may uncover pathologies of NAFLD, which is highly associated with obesity.

A Greater Improvement of Intrahepatic Fat Contents after 6 Months of Lifestyle Intervention Is Related to a Better Oxidative Stress and Inflammatory Status in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a disorder characterized by the excessive accumulation of lipids in the liver parenchyma. To date, there is no effective pharmacological treatment against NAFLD. Objective: To assess the relationship between the improvement of the intrahepatic fat content (IFC) in patients with NAFLD and metabolic syndrome and biomarkers of oxidative stress and inflammation after 6 months of lifestyle intervention. Patients diagnosed with NAFLD (n = 60 adults; 40-60 years old) residing in the Balearic Islands, Spain, were distributed in tertiles attending the improvement of IFC calculated by magnetic resonance imaging (MRI). Anthropometrics, blood pressure, maximal oxygen uptake, and pro/antioxidant and inflammatory biomarkers were determined in plasma before and after the lifestyle intervention. The improvement in IFC levels was higher in tertile 3 with respect to tertiles 2 and 1. The greatest improvement in IFC is related to cardiorespiratory fitness and adherence to the Mediterranean diet (ADM). Higher reductions in weight, body mass index (BMI), and alanine aminotransferase (ALT) were observed in tertile 3 with respect to tertile 1 after 6 months of intervention. The improvement in catalase, irisin, and cytokeratin 18 plasma levels were higher in tertile 3, whereas no differences were observed in superoxide dismutase activity. Malondialdehyde and protein carbonyl levels, as biomarkers of oxidative damage, remained unchanged in all groups. The present data show that the reduction of IFC is associated with an improvement in pro/antioxidant and pro-inflammatory status and a better cardiorespiratory fitness in NAFLD patients.