Non-alcoholic fatty liver disease and cardiovascular disease: assessing the evidence for causality

Effects of PNPLA3 I148M on hepatic lipid and very-low-density lipoprotein metabolism in humans

BACKGROUND

The phospholipase domain-containing 3 gene (PNPLA3)-148M variant is associated with liver steatosis but its influence on the metabolism of triglyceride-rich lipoproteins remains unclear. Here, we investigated the kinetics of large, triglyceride-rich very-low-density lipoprotein (VLDL), (VLDL₁ ), and smaller VLDL₂ in homozygotes for the PNPLA3-148M variant.

METHODS AND RESULTS

The kinetics of apolipoprotein (apo) B100 (apoB100) and triglyceride in VLDL subfractions were analysed in nine subjects homozygous for PNPLA3-148M and nine subjects homozygous for PNPLA3-148I (controls). Liver fat was >3-fold higher in the 148M subjects. Production rates for apoB100 and triglyceride in VLDL₁ did not differ significantly between the two groups. Likewise, production rates for VLDL₂ -apoB100 and -triglyceride, and fractional clearance rates for both apoB100 and triglyceride in VLDL₁ and VLDL₂ , were not significantly different.

CONCLUSIONS

Despite the higher liver fat content in PNPLA3 148M homozygotes, there was no increase in VLDL production. Equally, VLDL production was maintained at normal levels despite the putative impairment in cytosolic lipid hydrolysis in these subjects.

Metabolic biomarkers related to cardiac dysfunction in metabolic-dysfunction-associated fatty liver disease: a cross-sectional analysis

INTRODUCTION

Hepatic steatosis is associated with cardiac systolic and diastolic dysfunction. Therefore, we evaluated metabolites and their potential cardiovascular effects in metabolic-dysfunction-associated fatty liver disease (MAFLD).

MATERIALS AND METHODS

We conducted a cross-sectional study involving 75 participants (38 MAFLD and 37 controls). Hepatic steatosis was confirmed by hepatic ultrasonography and SteatoTestTM. Cardiac function was assessed using echocardiography. Metabolomic analysis was conducted using ultra-high-performance liquid chromatography-mass spectrometry.

RESULTS

The median age for participants' age was 45 (IQR 30-56.5), with gender distribution of 35 males and 40 females. MAFLD patients had lower levels of glycyl tyrosine (p-value < 0.001), lysophosphatidylcholine (LPC) (18:2/0:0) (p-value < 0.001), LPC (22:6) (p-value < 0.001), and ceramide (Cer) (d18:0/23:0) (p-value 0.003) compared to controls. MAFLD patients presented lower left ventricular ejection fraction (LVEF), E/A ratio, E/e' ratio, and average global longitudinal strain (GLS) values, with a p-value of 0.047, <0.001, 0.008, and <0.001, respectively. Decreased glycyl tyrosine levels were significantly correlated with reduced LVEF, even after performing multiple linear regression with 95% CI (1.34-3.394, p-value < 0.001). Moreover, decreased LPC (18:2/0:0) levels remained significantly associated with E/A ratio, even after adjusting for confounding factors with 95% CI (0.008-0.258, p-value = 0.042).

CONCLUSION

MAFLD patients are at risk for developing cardiac systolic and subclinical systolic dysfunctions, as well as diastolic dysfunction. Decreased glycyl tyrosine levels correlate with reduced LVEF and LPC (18:2/0:0) levels with diastolic dysfunction, even after adjusting for confounding factors, suggesting their potential to be used as metabolic biomarkers in detecting cardiovascular risk.

Cardiovascular Diseases and Non-Alcoholic Fatty Liver Disease: Relationship and Pathogenetic Aspects of Pharmacotherapy

The association of non-alcoholic fatty liver disease (NAFLD) and cardiovascular risk is currently one of the actively studied areas. The incidence of non-alcoholic fatty  liver disease continues to grow worldwide. In the structure of mortality rate of patients with non-alcoholic fatty  liver disease,  the first place is occupied by cardiovascular events: stroke and myocardial infarction. Studies have shown that the presence of severe liver fibrosis (F3-4) in NAFLD not only increases the risk of cardiovascular diseases (CVD), but also increases the risk  of  overall  mortality  by  69%  due  to mortality from cardiovascular causes. The degree of increased risk is associated with the degree of activity of non-alcoholic steatohepatitis (NASH). Despite the large number of works on this topic, we do not have a clear opinion on the impact on cardiovascular risk, interaction and the contribution of various factors, as well as algorithms for managing patients with non-alcoholic fatty liver disease to reduce the risk of cardiovascular diseases. This article describes the pathogenetic factors of formation of cardiovascular risks in patients with non-alcoholic fatty liver disease, proposed the idea of stratification of cardiovascular risks in these patients, taking into account changes in the structure of the liver (fibrosis) and function (clinical and biochemical activity) and also it describes the main directions of drug therapy, taking into account the common pathogenetic mechanisms for non-alcoholic fatty liver disease and cardiovascular diseases. The role of obesity, local fat depots, adipokines, and endothelial dysfunction as the leading pathogenetic factors of increased cardiovascular risk in patients with NAFLD is discussed. Among pathogenetically justified drugs in conditions of poly and comorbidity, hypolipidemic (statins, fibrates), angiotensin II receptor antagonists, beta-blockers, etc. can be considered. According to numerous studies, it becomes obvious that the assessment of cardiovascular risks in patients with NAFLD will probably allow prescribing cardiological drugs, selecting individualized therapy regimens, taking into account the form of NAFLD, and on the other hand, building curation taking into account the identified cardiovascular risks.

The use of screening tools for cardiovascular risk assessment in psoriasis – A case- control study

Background:

Psoriasis is a common, T-cell-mediated disease, affecting 0.44–2.8% of the general population in India. It is associated with a higher risk of cardiovascular disease possibly due to chronic inflammation. Those patients with severe psoriasis are at a higher risk of death due to cardiovascular disease. The use of scoring tools may help the care providers to assess cardiovascular risks in these patients.

Aims:

The aim of this study was to assess the cardiovascular risks in patients with severe psoriasis using the commonly used risk-assessment tools (Framingham risk score [FRS] and Pooled cohort equations [PCE]) and to understand the utility of these tools in practice.

Methods:

It is a case-control study performed in the dermatology outpatient department of a tertiary care center during the study period from January to December 2020. Consenting adults with chronic plaque psoriasis and psoriasis area and severity index (PASI) more than 10 were included in the study. The FRS and PCE risk scores were calculated for the patients and age- and sex-matched healthy controls.

Results:

A total of 213 patients were assessed and 30 patients were excluded. Of the 183 patients, 152 patients were assessed using FRS and 135 patients using PCE. Equal number of age- and sex-matched healthy controls were also assessed. The mean age of the patients assessed using the FRS and PCE was 47 ± 10.9 and 52.84 ± 8.9 years, respectively. The mean age of the controls was 45.52 ± 8.7 and 51.76 ± 8.1 years in the FRS and PCE groups, respectively. The male to female ratio was 1.92:1 and 2:1 in the FRS and PCE risk-score groups, respectively. The mean PASI score was 16.45 ± 7.88 and 15.6 ± 7.6 in the two groups, respectively. The 10-year risk estimate using FRS in the patients ranged from 0 to 26.9%. The mean and median estimates were 4.95 ± 5.7 and 2.8%, respectively, while 2.65 ± 4.7 and 0.8% in the controls (P = 0.001). The 10-year risk estimate in the patients using the PCE risk score ranged from 0.3 to 39.6%. The mean and median estimate in the patients was 8.17 ± 9.9 and 5.2%, respectively while they were 5.68 ± 7.5% and 2.6% in the controls (P = 0.024). The agreement between the FRS and PCE was found to be poor (Ϗ, 0.049). There was no statistically significant correlation of PASI to either the PCE risk score (P = 0.498) or FRS (P = 0.630).

Limitations:

A small sample size, and study in a tertiary care center may have resulted in sampling bias.

Conclusion:

Psoriasis is associated with a higher risk of cardiovascular disease. These tools may help a dermatologist in the primary prevention of cardiovascular disease. It can also help in the awareness of the increased risk of cardiovascular disease in patients.

Association between the liver fat score (LFS) and cardiovascular diseases in the national health and nutrition examination survey 1999-2016

BACKGROUND

The liver fat score (LFS) has been proposed to be a simple non-invasive marker of non-alcoholic fatty liver disease (NAFLD), which is highly prevalent in the general population. We tested its association with cardiovascular diseases (CVDs) and prognosis.

METHODS

17,244 adult participants from the National Health and Nutrition Examination Survey 1999-2016 were included. LFS is calculated from variables including serum aspartate transaminase/alanine transaminase (AST/ALT) ratio, fasting serum aspartate transaminase (AST) level, fasting serum insulin level, presence of metabolic syndrome and diabetes mellitus. In cross-sectional analysis, logistic regression was used to examine the association of the LFS with coronary heart disease (CHD), myocardial infarction (MI), congestive heart failure (CHF), stroke and angina pectoris. Mortality during follow-up was analysed using Cox proportional hazard regression.

RESULTS

LFS was associated with CHD (adjusted odds ratio [OR]: 1.09 per standard deviation [SD], 95% confidence interval [95% CI]: 1.03-1.15) (p = .003), CHF (1.11, 1.04-1.18) (p = .003) and angina pectoris (1.08, 1.02-1.13) (p = .005). LFS was not associated with MI or stroke, but was associated with increased all-cause and cardiovascular mortality with hazard ratios (HRs) of 1.10 (95% CI: 1.07-1.13) (p < .001) and 1.12 (95% CI: 1.06-1.17) (p < .001), respectively.

CONCLUSIONS

NAFLD is usually asymptomatic, but this large study of a large general population shows that LFS is associated with CHD, CHF, angina pectoris, cardiovascular and all-cause mortality. Determining the LFS is worthwhile, as it identifies people with NAFLD, who may also be at increased cardiovascular risk.Key MessagesLiver fat score (LFS), a non-invasive marker of non-alcoholic fatty liver disease (NAFLD), is associated with coronary heart disease (CHD), congestive heart failure (CHF) and angina.LFS is also associated with increased cardiovascular and all-cause mortality.Determining the LFS is worthwhile as it identifies people with NAFLD as well as increased cardiovascular risk.

Electronic health record-based genome-wide meta-analysis provides insights on the genetic architecture of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a complex disease linked to several chronic diseases. We aimed at identifying genetic variants associated with NAFLD and evaluating their functional consequences. We performed a genome-wide meta-analysis of 4 cohorts of electronic health record-documented NAFLD in participants of European ancestry (8,434 cases and 770,180 controls). We identify 5 potential susceptibility loci for NAFLD (located at or near GCKR, TR1B1, MAU2/TM6SF2, APOE, and PNPLA3). We also report a potentially causal effect of lower LPL expression in adipose tissue on NAFLD susceptibility and an effect of the FTO genotype on NAFLD. Positive genetic correlations between NAFLD and cardiometabolic diseases and risk factors such as body fat accumulation/distribution, lipoprotein-lipid levels, insulin resistance, and coronary artery disease and negative genetic correlations with parental lifespan, socio-economic status, and acetoacetate levels are observed. This large GWAS meta-analysis reveals insights into the genetic architecture of NAFLD.

Oxidative stress and cardiometabolic biomarkers in patients with non-alcoholic fatty liver disease

Oxidative stress is assumed to be the underlying feature of non-alcoholic fatty liver disease (NAFLD). To our knowledge, the mutual involvement of redox status homeostasis parameters [i.e., advanced oxidation protein products (AOPP), pro-oxidant-antioxidant balance (PAB), total oxidant status (TOS), total antioxidant status (TAS) and oxidative-stress index (OSI)] and cardiometabolic biomarkers in subjects with NAFLD has not been examined yet. Accordingly, we aimed to investigate this potential relationship. A total of 122 subjects with NAFLD were compared with 56 participants without NAFLD. The diagnosis of NAFLD was confirmed by abdominal ultrasound. Anthropometric and biochemical parameters were measured. OSI, Castelli’s Risk Index I (CRI-I) and Castelli’s Risk Index II (CRI-II) were calculated. Univariate and multivariate binary logistic regression analysis were used to test the predictions of oxidative stress and cardiometabolic markers, respectively for NAFLD. Principal component analysis (PCA) was applied to explore its mutual effect on NAFLD status. Significant positive associations of CRI-I, CRI-II, high sensitivity C-reactive protein (hsCRP) and AOPP with NAFLD were found. PCA analysis extracted 3 significant factors: Oxidative stress-cardiometabolic related factor (i.e., triglycerides, AOPP, HDL-c and HbA1c)-explained 36% of variance; Pro-oxidants related factor (i.e., TOS and PAB)-explained 17% of variance; and Antioxidants related factor (i.e., TAS)-explained 15% of variance of the tested parameters. Moreover, binary logistic regression analysis revealed significant predictive ability of Oxidative stress-cardiometabolic related factor (p < 0.001) and Pro-oxidants related factor (p < 0.05) for NAFLD status. In addition to oxidative stress (i.e., determined by higher AOPP levels), dyslipidemia (i.e., determined by higher lipid indexes: CRI-I and CRI-II) and inflammation (determined by higher hsCRP) are independently related to NAFLD status. The mutual involvement of pro-oxidants (i.e., TOS and PAB), or the joint involvement of pro-oxidants (i.e., AOPP) and cardiometabolic parameters (i.e., HbA1c, triglycerides and HDL-c) can differentiate subjects with NAFLD from those individuals without this metabolic disorder. New studies are needed to validate our results in order to find the best therapeutic approach for NAFLD.

The Risk of Type 2 Diabetes and Coronary Artery Disease in Non-obese Patients With Non-alcoholic Fatty Liver Disease: A Cohort Study

Background: Non-alcoholic fatty liver disease (NAFLD) is not uncommon in non-obese subjects, referred to as non-obese NAFLD. It is not fully determined whether non-obese NAFLD is associated with increased risks of type 2 diabetes (T2D) and coronary artery disease (CAD) in Chinese. This study aimed to examine the association between NAFLD and risks of T2D and CAD in a non-obese Chinese population. Methods: The present cohort study included two stages. In the first cross-sectional study, 16,093 non-obese subjects with a body max index (BMI) < 25.0 kg/m² were enrolled from The Second Xiangya Hospital, China, from 2011 to 2014. Hepatic steatosis was evaluated by ultrasonography examination. Logistic regression analyses were used to examine the association of non-obese NAFLD with T2D and CAD at baseline. In the subsequent 5-year follow-up study, 12,649 subjects free of T2D and CAD at baseline were included, and the incidence of T2D and CAD were observed. Cox proportional hazard regression analyses were performed to determine the risk of incident T2D and CAD with NAFLD. Results: At baseline, the prevalence of NAFLD, T2D and CAD were 10.7% (1,717/16,093), 3.3% (529/16,093) and 0.7% (113/16,093), respectively. The univariate logistic regression analyses showed NAFLD associated with both T2D and CAD. Moreover, in a multivariate logistic regression model, NAFLD remained independently associated with T2D (OR: 2.7, 95% CI: 2.2-3.3, p < 0.001). However, no significant association was found between NAFLD and CAD by the multivariate logistic regression analyses (OR: 1.1, 95% CI: 0.6-1.8, p = 0.854). During a 5-year follow-up period, 177 (1.4%) patients developed T2D, and 134 (1.1%) developed CAD, respectively. In univariate Cox regression models, NAFLD associated with both T2D and CAD. Moreover, the multivariate Cox regression analysis revealed that NAFLD independently associated with an increased risk of T2D (HR: 2.3, 95% CI: 1.7-3.2, p < 0.001). However, the association between NAFLD and incident CAD was lost in the multivariate Cox regression analysis (HR = 1.5, 95% CI: 1.0-2.4, p = 0.059). Conclusions: NAFLD was an independent risk factor for T2D in non-obese subjects. However, no significant association was observed between non-obese NAFLD and incident CAD after adjusting other traditional cardiovascular risk factors, suggesting these factors might mediate the increased incidence of CAD in non-obese NAFLD patients.

Prevalence, Diagnosis, and Treatment with 3 Different Statins of Non-alcoholic Fatty Liver Disease/Non-alcoholic Steatohepatitis in Military Personnel. Do Genetics Play a Role?

Background:

Non-alcoholic fatty liver disease (NAFLD) and its severe form, non-alcoholic steatohepatitis (NASH), are major health problems worldwide. Genetics may play a role in the pathogenesis of NAFLD/NASH.

Aim:

To investigate the prevalence of NAFLD/NASH in 5,400 military personnel and evaluate the effect of treatment with 3 statins on NAFLD/NASH using 2 non-invasive scores [NAFLD Activity Score (NAS); Fibrosis-4 score (FIB-4)].

Methods:

During the mandatory annual medical check-up, military personnel underwent a clinical and laboratory evaluation. Participants with NAFLD/NASH were randomized into 4 groups (n=151 each): diet-exercise, atorvastatin, rosuvastatin, or pitavastatin for 1 year (i.e., until the next routine evaluation).

Results:

From all the participants, 613 had NAFLD/NASH (prevalence 11.3 vs 39.8% in the general population, p<0.001), and a total of 604 consented to participate in the study. After a year of treatment, the diet-exercise group showed no significant changes in both scores (NAS 4.98 baseline vs. 5.62, p=0.07; FIB-4 3.42 vs. 3.52, p=0.7). For the atorvastatin group, both scores were reduced (NAS 4.97 vs 1.95, p<0.001, FIB-4 3.56 vs 0.83, p<0.001), for rosuvastatin (NAS 5.55 vs 1.81, p<0.001, FIB-4 3.61 vs 0.79, p<0.001), and for pitavastatin (NAS 4.89 vs 1.99, p<0.001, FIB-4 3.78 vs 0.87, p<0.001).

Conclusions:

Atorvastatin, rosuvastatin, and pitavastatin have a beneficial and safe effect in NAFLD/NASH patients as recorded by the improvement in the NAS (representing NAFLD activity) and FIB-4 (representing liver fibrosis) scores. Since both those with and without NAFLD/- NASH shared several baseline characteristics, genetics may play a role in the pathogenesis of NAFLD/NASH and its treatment with statins.

Excess Body Weight and Metabolic (Dysfunction)-Associated Fatty Liver Disease (MAFLD)

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) describes a continuum of liver abnormalities from simple nonalcoholic fatty liver (NAFL) to nonalcoholic fatty liver hepatitis or steatohepatitis (NASH) to NASH fibrosis. It has a variable course, but just like alcoholic fatty liver disease, it can lead to liver cirrhosis and cancer (hepatocellular carcinoma).

SUMMARY

NAFLD is a clinical entity characterized by the presence of liver steatosis, which affects at least 5% of hepatocytes. Affected are people who consume little or no alcohol and who have no secondary cause of liver steatosis such as viral hepatitis, drug intake (e.g., tamoxifen, amiodarone, methotrexate, etc.), or lipodystrophy. NAFLD is, nowadays, the most common liver disease in Europe, with an estimated prevalence of 25%. The currently widely recognized recommendation for the therapy of NAFLD is a lifestyle modification with the goal of weight loss. Although no drugs are currently approved for the treatment of NAFLD, several candidates are in clinical trials. Besides weight loss and physical activity, corresponding single active ingredients or combination therapies are intended to stop the progression of the disease and, in the best case, reverse it. The newly propagated name MAFLD (metabolic-associated fatty liver disease) should indicate that the disease is associated with metabolic disorders. The term MAFLD also implies multiple overlapping causes and drivers of this soaring disease.

KEY MESSAGES

The prevalence of NAFLD continues to rise worldwide. NAFLD, NASH, and fibrosis in NAFLD occur predominantly in patients with obesity and type 2 diabetes (T2DM) or else precede these conditions. The progression of NAFLD is highly dependent on changes in glucose, lipid metabolism, and fibrogenesis. A new definition and nomenclature of fatty liver disease, "metabolic associated fatty liver disease" (MAFLD), should be discussed carefully, since around 40% of the global population with NAFLD are classified as non-obese and almost 1/5 as lean. Since the pathogenesis of fatty liver disease, obesity, and glucose and lipid metabolism diseases are very closely related, it is important to continue to look for mechanisms that these diseases have in common and develop new therapeutic approaches.

Nonalcoholic Fatty Liver Disease and Cardiovascular Disease: Overlapping Mechanisms

Nonalcoholic fatty liver disease (NAFLD) denotes a condition with excess fat in the liver. The prevalence of NAFLD is increasing, averaging > 25% of the Western population. In 25% of the patients, NAFLD progresses to its more severe form: nonalcoholic steatohepatitis and >25% of these progress to cirrhosis following activation of inflammatory and fibrotic processes. NAFLD is associated with obesity, type 2 diabetes, and the metabolic syndrome and represents a considerable and increasing health burden. In the near future, NAFLD cirrhosis is expected to be the most common cause for liver transplantation. NAFLD patients have an increased risk of developing cardiovascular disease as well as liver-related morbidity. In addition, hepatic steatosis itself appears to represent an independent cardiovascular risk factor. In the present review, we provide an overview of the overlapping mechanisms and prevalence of NAFLD and cardiovascular disease.

Relationship between AGT rs2493132 polymorphism and the risk of coronary artery disease in patients with NAFLD in the Chinese Han population

Objective

To investigate the relationship between angiotensin (AGT) rs2493132 gene polymorphism and the risk of developing non-alcoholic fatty liver disease (NAFLD) and coronary artery disease (CAD) in the Chinese Han population.

Methods

Polymerase chain reaction was performed to determine AGT genotypes. Anthropometric and clinical data were investigated and statistically analyzed in the clinical laboratory department of Qingdao Municipal Hospital.

Results

The AGT rs2493132 CT + TT genotype was an important risk factor for CAD in patients with NAFLD and NAFLD + CAD in healthy controls. The AGT rs2493132 T allele increased the risk of NAFLD + CAD in healthy controls. The AGT rs2493132 CT + TT genotype and T allele also significantly increased the risk of CAD in patients with NAFLD after adjustments for age, sex, and body mass index. In addition, AGT rs2493132 T allele carriers showed higher total cholesterol (TC) and low-density lipoprotein (LDL) levels compared with non-carriers.

Conclusions

The AGT rs2493132 CT + TT genotype and T allele significantly increased the risk of developing CAD in patients with NAFLD in the Chinese Han population. The AGT rs2493132 T allele was associated with increased serum TC and LDL levels.

Low testosterone and cardiometabolic risks in a real-world study of US male firefighters

Low serum total testosterone (TT) is associated with increased cardiovascular risk and metabolic derangements, with fatty liver (FL) emerging as an additional cardiometabolic threat. We investigated the associations between TT and cardiometabolic (CM) health in 298 US male firefighters. Cross-sectional data from occupational health examination were analyzed. TT was categorized as low (< 264 ng/dL), borderline (264-399 ng/dL), and reference (400-916 ng/dL). Conventional CM risk factors were compared among TT categories, and between firefighters with and without FL. 81% of firefighters were obese/overweight; almost 40% had FL. In the low-TT group, only 3.1% had normal BMI, while 78.1% had FL. The low-TT group had a worse CM profile, independently of age and BMI, and a fourfold higher adjusted odds of having FL. FL was associated with lower TT, regardless of age, BMI and HbA1c. Having a FL, HbA1c ≥ 5.7% or triglycerides ≥ 150 mg/dL increased the odds for low-TT by 4.1, 2.7 and 6.6 times, respectively. These real-world data reveal strong associations between low-TT and CM risk factors and support a call for action towards screening for low-TT and FL, regardless of age, BMI or dysmetabolic conditions in firefighters. Recognizing cardiometabolic risks in firefighters provides an opportunity to lessen cardiovascular diseases burden.

Mitochondrial Lipid Homeostasis at the Crossroads of Liver and Heart Diseases

The prevalence of NAFLD (non-alcoholic fatty liver disease) is a rapidly increasing problem, affecting a huge population around the globe. However, CVDs (cardiovascular diseases) are the most common cause of mortality in NAFLD patients. Atherogenic dyslipidemia, characterized by plasma hypertriglyceridemia, increased small dense LDL (low-density lipoprotein) particles, and decreased HDL-C (high-density lipoprotein cholesterol) levels, is often observed in NAFLD patients. In this review, we summarize recent genetic evidence, proving the diverse nature of metabolic pathways involved in NAFLD pathogenesis. Analysis of available genetic data suggests that the altered operation of fatty-acid β-oxidation in liver mitochondria is the key process, connecting NAFLD-mediated dyslipidemia and elevated CVD risk. In addition, we discuss several NAFLD-associated genes with documented anti-atherosclerotic or cardioprotective effects, and current pharmaceutical strategies focused on both NAFLD treatment and reduction of CVD risk.

Non-alcoholic fatty liver disease, insulin resistance, metabolic syndrome and their association with vascular risk

The prevalence of non-alcoholic fatty liver disease (NAFLD), one of the most common liver diseases, is rising. About 25% of adults worldwide are probably affected by NAFLD. Insulin resistance (IR) and fat accumulation in the liver are strongly related. The association between NAFLD, metabolic syndrome (MetS) and IR is established, but an independent impact of NAFLD on vascular risk and progression of cardiovascular (CV) disease (CVD) still needs to be confirmed. This narrative review considers the evidence regarding the link between NAFLD, IR and CVD risk. There is strong evidence for a "concomitantly rising incidence" of NAFLD, IR, MetS and CVD but there is no definitive evidence regarding whether NAFLD is, or is not, an independent and significant risk factor the development of CVD. There are also considerations that type 2 diabetes mellitus (T2DM) may be a common link between NAFLD/non-alcoholic steatohepatitis (NASH) and CVD. NAFLD may be associated with widespread abnormal peri-organ or intra-organ fat (APIFat) deposition (e.g. epicardial adipose tissue) which may further contribute to CV risk. It is clear that NAFLD patients have a greater CV risk (independent or not) which needs to be addressed in clinical practice.

Short-Term Physical Inactivity Induces Endothelial Dysfunction

Objective

This study examined the effects of a short-term reduction in physical activity, and subsequent resumption, on metabolic profiles, body composition and cardiovascular (endothelial) function.

Design

Twenty-eight habitually active (≥10,000 steps/day) participants (18 female, 10 male; age 32 ± 11 years; BMI 24.3 ± 2.5 kg/m²) were assessed at baseline, following 14 days of step-reduction and 14 days after resuming habitual activity.

Methods

Physical activity was monitored throughout (SenseWear Armband). Endothelial function (flow mediated dilation; FMD), cardiorespiratory fitness ( V . ⁢ O 2 peak) and body composition including liver fat (dual-energy x-ray absorptiometry and magnetic resonance spectroscopy) were determined at each assessment. Statistical analysis was performed using one-way within subject's ANOVA; data presented as mean (95% CI).

Results

Participants decreased their step count from baseline by 10,111 steps/day (8949, 11,274; P < 0.001), increasing sedentary time by 103 min/day (29, 177; P < 0.001). Following 14 days of step-reduction, endothelial function was reduced by a 1.8% (0.4, 3.3; P = 0.01) decrease in FMD. Following resumption of habitual activity, FMD increased by 1.4%, comparable to the baseline level 0.4% (-1.8, 2.6; P = 1.00). Total body fat, waist circumference, liver fat, whole body insulin sensitivity and cardiorespiratory fitness were all adversely affected by 14 days step-reduction (P < 0.05) but returned to baseline levels following resumption of activity.

Conclusion

This data shows for the first time that whilst a decline in endothelial function is observed following short-term physical inactivity, this is reversed on resumption of habitual activity. The findings highlight the need for public health interventions that focus on minimizing time spent in sedentary behavior.

The Relationship Between Type 2 Diabetes, NAFLD, and Cardiovascular Risk

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are strongly associated. Both also associate with an increased risk of cardiovascular disease (CVD).

RECENT FINDINGS

Several studies have provided evidence that NAFLD could be an independent CVD risk factor. Given the strong association between NAFLD and T2DM, assessing the independent CV effect of these two conditions remains challenging. However, patients with T2DM and NAFLD exhibit higher risk of CVD compared with T2DM without NAFLD suggesting a potential synergistic increase of CV risk in patients with both T2DM and NAFLD supported by several shared pathophysiological pathways. Several anti-diabetic therapies have shown beneficial effect on both NAFLD and CVD. Patients with T2DM and NAFLD should be considered at high risk of CVD and could benefit from more intensive CV prevention. Additional long-term follow-up is needed to demonstrate that the treatment of NAFLD effectively reduces the risk of CVD.

A novel numerical model of combination levels of C-peptide and insulin in coronary artery disease risk prediction

OBJECTIVE

Insulin resistance is a major risk factor for coronary artery disease (CAD). The C-peptide-to-insulin ratio (C/I) is associated with hepatic insulin clearance and insulin resistance. The current study was designed to establish a novel C/I index (CPIRI) model and provide early risk assessment of CAD.

METHODS

A total of 865 adults diagnosed with new-onset diabetes mellitus (DM) within one year and 54 healthy controls (HC) were recruited to develop a CPIRI model. The CPIRI model was established with fasting C/I as the independent variable and homeostasis model assessment of insulin resistance (HOMA-IR) as the dependent variable. Associations between the CPIRI model and the severity of CAD events were also assessed in 45 hyperglycemic patients with CAD documented via coronary arteriography (CAG) and whom underwent stress echocardiography (SE) and exercise electrocardiography test (EET).

RESULTS

Fasting C-peptide/insulin and HOMA-IR were hyperbolically correlated in DM patients and HC, and log(C/I) and log(HOMA-IR) were linearly and negatively correlated. The respective correlational coefficients were -0.83 (p < 0.001) and -0.76 (p < 0.001). The equations CPIRI(DM) = 670/(C/I)2.24 + 0.25 and CPIRI(HC) = 670/(C/I)2.24 - 1 (F = 1904.39, p < 0.001) were obtained. Patients with insulin resistance exhibited severe coronary artery impairment and myocardial ischemia. In CAD patients there was no significant correlation between insulin resistance and the number of vessels involved.

CONCLUSIONS

CPIRI can be used to effectively evaluate insulin resistance, and the combination of CPIRI and non-invasive cardiovascular examination is of great clinical value in the assessment of CAD.

NAFLD and Cardiovascular Diseases: Epidemiological, Mechanistic and Therapeutic Considerations

Overwhelming evidence suggests an association of cardiovascular disease (CVD) with non-alcoholic fatty liver disease (NAFLD); however, the underlying mechanisms remain largely speculative. It is, however, likely that common mechanisms contribute to the development of CVD and NAFLD, with lifestyle factors such as smoking, sedentary lifestyle with poor nutrition habits and physical inactivity being major candidates. These behavioral factors, on a predisposing genetic background, trigger changes in gut microbiota, inflammation, dyslipidemia and oxidative stress, leading to metabolic syndrome, diabetes and obesity as well as atherosclerosis. Treatment options to counteract both the progression and development of CVD and NAFLD include lifestyle interventions, optimal medical therapy of comorbid conditions and, as final possibility, bariatric surgery. As no causal pharmacotherapy of NAFLD is available, further research is urgently needed to address the unmet need of a growing population with NAFLD and CVD.

Nonalcoholic Fatty Liver Disease and Cardiovascular Diseases: The Heart of the Matter

Nonalcoholic fatty liver disease (NAFLD) has emerged as the most frequent cause of liver disease worldwide, comprising a plethora of conditions, ranging from steatosis to end-stage liver disease. Cardiovascular disease (CVD) has been associated with NAFLD and CVD-related events represent the main cause of death in patients with NAFLD, surpassing liver-related mortality. This association is not surprising as NAFLD has been considered a part of the metabolic syndrome and has been related to numerous CVD risk factors, namely, insulin resistance, abdominal obesity, dyslipidemia, hyperuricemia, chronic kidney disease, and type 2 diabetes. Moreover, both NAFLD and CVD present similar pathophysiological mechanisms, such as increased visceral adiposity, altered lipid metabolism, increased oxidative stress, and systemic inflammation that could explain their association. Whether NAFLD increases the risk for CVD or these diagnostic entities represent distinct manifestations of the metabolic syndrome has not yet been clarified. This review focuses on the relation between NAFLD and the spectrum of CVD, considering the pathophysiological mechanisms, risk factors, current evidence, and future directions.

The Role of H2S in the Metabolism of Glucose and Lipids

Glucose and lipids are essential elements for maintaining the body's homeostasis, and their dysfunction may participate in the pathologies of various diseases, particularly diabetes, obesity, metabolic syndrome, cardiovascular ailments, and cancers. Among numerous endogenous mediators, the gasotransmitter hydrogen sulfide (H₂S) plays a central role in the maintenance of glucose and lipid homeostasis. Current evidence from both pharmacological studies and transgenic animal models suggest a complex relationship between H₂S and metabolic dysregulation, especially in diabetes and obesity. This notion is achieved through tissue-specific expressions and actions of H₂S on target metabolic and hormone organs including the pancreas, skeletal muscle, livers, and adipose. In this chapter, we will summarize the roles and mechanisms of H₂S in several metabolic organs/tissues that are necessary for glucose and lipid metabolic homeostasis. In addition, future research directions and valuable therapeutic avenues around the pharmacological regulation of H₂S in glycolipid metabolism disorder will be also discussed.

Effects of TM6SF2 E167K on hepatic lipid and very low-density lipoprotein metabolism in humans

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic lipid accumulation. The transmembrane 6 superfamily member 2 (TM6SF2) E167K genetic variant associates with NAFLD and with reduced plasma triglyceride levels in humans. However, the molecular mechanisms underlying these associations remain unclear. We hypothesized that TM6SF2 E167K affects hepatic very low-density lipoprotein (VLDL) secretion and studied the kinetics of apolipoprotein B100 (apoB100) and triglyceride metabolism in VLDL in homozygous subjects. In 10 homozygote TM6SF2 E167K carriers and 10 matched controls, we employed stable-isotope tracer and compartmental modeling techniques to determine apoB100 and triglyceride kinetics in the 2 major VLDL subfractions: large triglyceride-rich VLDL₁ and smaller, less triglyceride-rich VLDL₂. VLDL₁-apoB100 production was markedly reduced in homozygote TM6SF2 E167K carriers compared with controls. Likewise, VLDL₁-triglyceride production was 35% lower in the TM6SF2 E167K carriers. In contrast, the direct production rates for VLDL₂-apoB100 and triglyceride were not different between carriers and controls. In conclusion, the TM6SF2 E167K genetic variant was linked to a specific reduction in hepatic secretion of large triglyceride-rich VLDL₁. The impaired secretion of VLDL₁ explains the reduced plasma triglyceride concentration and provides a basis for understanding the lower risk of cardiovascular disease associated with the TM6SF2 E167K genetic variant.

NAFLD, and cardiovascular and cardiac diseases: Factors influencing risk, prediction and treatment

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD), affecting up to around 30% of the world's adult population, causes considerable liver-related and extrahepatic morbidity and mortality. Strong evidence indicates that NAFLD (especially its more severe forms) is associated with a greater risk of all-cause mortality, and the predominant cause of mortality in this patient population is cardiovascular disease (CVD). This narrative review aims to discuss the strong association between NAFLD and increased risk of cardiovascular, cardiac and arrhythmic complications. Also discussed are the putative mechanisms linking NAFLD to CVD and other cardiac/arrhythmic complications, with a brief summary of CVD risk prediction/stratification and management of the increased CVD risk observed in patients with NAFLD.

RESULTS

NAFLD is associated with an increased risk of CVD events and other cardiac complications (left ventricular hypertrophy, valvular calcification, certain arrhythmias) independently of traditional CVD risk factors. The magnitude of risk of CVD and other cardiac/arrhythmic complications parallels the severity of NAFLD (especially liver fibrosis severity). There are most likely multiple underlying mechanisms through which NAFLD may increase risk of CVD and cardiac/arrhythmic complications. Indeed, NAFLD exacerbates hepatic and systemic insulin resistance, promotes atherogenic dyslipidaemia, induces hypertension, and triggers synthesis of proatherogenic, procoagulant and proinflammatory mediators that may contribute to the development of CVD and other cardiac/arrhythmic complications.

CONCLUSION

Careful assessment of CVD risk is mandatory in patients with NAFLD for primary prevention of CVD, together with pharmacological treatment for coexisting CVD risk factors.

Acute Coronary Syndromes and Nonalcoholic Fatty Liver Disease: "Un Affaire de Coeur"

BACKGROUND AND AIMS

Both nonalcoholic fatty liver disease (NAFLD) and ischemic heart disease have common pathogenic links. Evidence for the association of NAFLD with acute coronary syndromes (ACS), complex multivessel coronary artery disease (CAD), and increased mortality risk in ACS patients is still under investigation. Therefore, we conducted a systematic review aiming to clarify these gaps in evidence.

METHODS

We conducted a systematic search on PubMed and EMBASE with predefined keywords searching for observational studies published till August 2020. NAFLD diagnosis was accepted if confirmed through biopsy, imaging techniques, surrogate markers, or codes. Full articles that satisfied our inclusion and exclusion criteria were included in the systematic review. We used the NHLBI quality assessment tool to evaluate included studies.

RESULTS

Seventeen observational studies with a total study population of approximately 21 million subjects were included. Eleven studies evaluated whether NAFLD is an independent risk factor for developing ACS with conflicting results, of which eight studies demonstrated a significant association between NAFLD and ACS, mainly in Asian populations, while three reported a lack of an independent association. Conflicting results were reported in studies conducted in Europe and North America. Moreover, a total of five studies evaluated whether NAFLD and fatty liver severity in ACS patients are associated with a complex multivessel CAD disease, where all studies confirmed a significant association. Furthermore, seven out of eight studies evaluating NAFLD and hepatic steatosis severity as a predictor of all-cause and cardiovascular mortality and in-hospital major adverse cardiovascular events (MACE) in ACS patients demonstrated a significant independent association.

CONCLUSIONS

NAFLD patients are associated with an independently increased risk of developing ACS, mainly in Asian populations, with inconsistent results in North American and European individuals. Moreover, NAFLD and hepatic steatosis severity were both independently correlated with complex multivessel CAD, mortality, and in-hospital MACE in ACS patients.

The pivotal role of heme Oxygenase-1 in reversing the pathophysiology and systemic complications of NAFLD

The pathogenesis and molecular pathways involved in non-alcoholic fatty liver disease (NAFLD) are reviewed, as well as what is known about mitochondrial dysfunction that leads to heart disease and the progression to steatohepatitis and hepatic fibrosis. We focused our discussion on the role of the antioxidant gene heme oxygenase-1 (HO-1) and its nuclear coactivator, peroxisome proliferator-activated receptor-gamma coactivator (PGC1-α) in the regulation of mitochondrial biogenesis and function and potential therapeutic benefit for cardiac disease, NAFLD as well as the pharmacological effect they have on the chronic inflammatory state of obesity. The result is increased mitochondrial function and the conversion of white adipocyte tissue to beige adipose tissue ("browning of white adipose tissue") that leads to an improvement in signaling pathways and overall liver function. Improved mitochondrial biogenesis and function is essential to preventing the progression of hepatic steatosis to NASH and cirrhosis as well as preventing cardiovascular complications.

Mediterranean diet is inversely associated with steatosis and fibrosis and decreases ten-year diabetes and cardiovascular risk in NAFLD subjects: Results from the ATTICA prospective cohort study

BACKGROUND AND AIMS

We assessed the association of Mediterranean diet with NAFLD and their interaction in predicting ten-year diabetes onset and first fatal/non-fatal cardiovascular disease (CVD) incidence.

METHODS

The ATTICA prospective observational study in Athens, Greece included 1,514 men and 1,528 women (>18 years old) free-of-CVD at baseline. Liver steatosis and fibrosis indices were calculated. Mediterranean diet adherence was assessed through MedDietScore. At the ten-year follow-up visit, CVD evaluation was performed in an a priori specified subgroup of n = 2,020 participants and diabetes onset in n = 1,485 free-of-diabetes participants.

RESULTS

MedDietScore was inversely associated with steatosis and fibrosis; e.g. in the case of the TyG index the Odds Ratio (OR) of the 3rd vs. 1st MedDietScore tertile was = 0·53, [95% Confidence Interval (95% CI) (0·29, 0·95)] and the associations persisted in multi-adjusted models. NAFLD predicted incident diabetes prospectively over a ten year period [HR = 1·87, 95% CI (0·75, 4·61)] and the association remained significant only in subjects with low MedDietScore (below median) whereas diabetes onset among subjects with higher MedDietScore was not influenced by NAFLD. Similarly, NAFLD predicted CVD [Hazard Ratio (HR) = 3·01, 95%CI(2·28, 3·95)]; the effect remained significant only in subjects with MedDietScore below median [HR = 1·38, 95% CI (1·00, 1·93)] whereas it was essentially null [HR = 1·00,95% CI (0·38, 2·63)] among subjects with higher score. Mediation analysis revealed that adiponectin and adiponectin-to-leptin ratio were the strongest mediators.

CONCLUSIONS

We report an inverse association between Mediterranean diet and NAFLD. Mediterranean diet protected against diabetes and CVD prospectively among subjects with NAFLD.

Role of Agents for the Treatment of Diabetes in the Management of Nonalcoholic Fatty Liver Disease

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease (NAFLD) is an often unrecognized complication of type 2 diabetes (T2DM) associated with significant economic burden and poor long-term hepatic and extrahepatic outcomes. Our goal is to review evidence about the complex association between NAFLD and T2DM and highlight the potential for disease co-management with the available medications used for the treatment of diabetes.

RECENT FINDINGS

A milieu of metabolic factors such as insulin resistance, glucotoxicity, and lipotoxicity, as well as genetics and other factors, contribute to the pathogenesis and co-existence of NAFLD with T2DM. The presence of T2DM in patients with NAFLD increases the risk of disease progression to steatohepatitis (NASH) and advanced fibrosis, cirrhosis, and even hepatocellular carcinoma. In addition to lifestyle modification, pioglitazone and glucagon-like peptide 1 receptor agonists (GLP-1RAs) both reduce the high cardiovascular risk and improve liver histology in patients with NAFLD. Sodium-glucose cotransporter (SGLT-2) inhibitors also appear to reverse metabolic abnormalities as well as liver disease in NAFLD, but their impact on liver histology has not been fully established. Lastly, metformin, dipeptidyl dipetidase-4 (DPP-4) inhibitors, and insulin appear to have modest to no effect on modifying the natural history of NAFLD. Early recognition of NAFLD and monitoring for NASH with advanced liver fibrosis in patients with T2DM are crucial. The presence of NASH in a patient with T2DM should call for taking advantage of antidiabetic medications with proven efficacy to improve cardiometabolic health and prevent liver disease progression.

Human and molecular genetics shed lights on fatty liver disease and diabetes conundrum

The causal role of abdominal overweight/obesity, insulin resistance and type 2 diabetes (T2D) on the risk of fatty liver disease (FLD) has robustly been proven. A consensus of experts has recently proposed the novel definition of 'metabolic dysfunction-associated fatty liver disease, MAFLD' instead of 'nonalcoholic fatty liver disease, NAFLD', emphasizing the central role of dysmetabolism in the disease pathogenesis. Conversely, a direct and independent contribution of FLD per se on risk of developing T2D is still a controversial topic. When dealing with FLD as a potential risk factor for T2D, it is straightforward to think of hepatic insulin resistance as the most relevant underlying mechanism. Emerging evidence supports genetic determinants of FLD (eg PNPLA3, TM6SF2, MBOAT7, GCKR, HSD17B13) as determinants of insulin resistance and T2D. However, recent studies highlighted that the key molecular mechanism of dysmetabolism is not fat accumulation per se but the degree of hepatic fibrosis (excess liver fat content-lipotoxicity), leading to reduced insulin clearance, insulin resistance and T2D. A consequence of these findings is that drugs that will ameliorate liver fat accumulation and fibrosis in principle may also exert a beneficial effect on insulin resistance and risk of T2D in individuals with FLD. Finally, initial findings show that these genetic factors might be directly implicated in modulating pancreatic beta-cell function, although future studies are needed to fully understand this relationship.

Genetic predisposition in metabolic-dysfunction-associated fatty liver disease and cardiovascular outcomes-Systematic review

BACKGROUND

Despite the demonstrated increased cardiovascular (CV) risk associated with metabolic-dysfunction-associated fatty liver disease (MAFLD), genetic variants predisposing to MAFLD were not constantly associated with CV events. Recently, rs641738C > T near membrane-bound O-acyltransferase domain-containing 7 (MBOAT7) has been studied in MAFLD and CV outcomes. Therefore, we aimed to evaluate the association between rs641738C > T in the presence and severity of hepatic steatosis, fibrosis, biochemical markers and progression to hepatocellular carcinoma (HCC), in addition to CV outcomes in MAFLD.

MATERIALS AND METHODS

An electronic search on PubMed, Embase and Cochrane Library for articles published till 23 March 2020 was systematically performed. Articles were screened, and data extracted from eligible studies by two reviewers independently.

RESULTS

Studies conducted on adults with MAFLD involving European, Hispanic and African American populations evaluating rs641738 reported reduced hepatic expression of MBOAT7, increased hepatic fat content, severity of MAFLD, susceptibility to develop NASH, advanced fibrosis and HCC in adults. However, most articles involving Asian individuals contradicted these findings. Studies involving obese children associated rs641738 with increased plasma alanine aminotransferase (ALT) levels, while its association with MAFLD remains inconsistent. The rs641738 variant was assessed as a MAFLD susceptibility gene in coronary artery disease (CAD) reporting neutral effects.

CONCLUSIONS

Despite inconclusive results in Asian populations, rs641738C > T near MBOAT7 is associated with increased hepatic fat, MAFLD severity, susceptibility to develop NASH, advanced fibrosis and HCC in adults from Caucasian, Hispanic and African American ethnicities with MAFLD, as well as elevated ALT levels in children, while exerting neutral effects in CAD.

NAFLD and increased risk of cardiovascular disease: clinical associations, pathophysiological mechanisms and pharmacological implications

Non-alcoholic fatty liver disease (NAFLD) is a public health problem, affecting up to a third of the world's adult population. Several cohort studies have consistently documented that NAFLD (especially in its more advanced forms) is associated with a higher risk of all-cause mortality and that the leading causes of death among patients with NAFLD are cardiovascular diseases (CVDs), followed by extrahepatic malignancies and liver-related complications. A growing body of evidence also indicates that NAFLD is strongly associated with an increased risk of major CVD events and other cardiac complications (ie, cardiomyopathy, cardiac valvular calcification and cardiac arrhythmias), independently of traditional cardiovascular risk factors. This narrative review provides an overview of the literature on: (1) the evidence for an association between NAFLD and increased risk of cardiovascular, cardiac and arrhythmic complications, (2) the putative pathophysiological mechanisms linking NAFLD to CVD and other cardiac complications and (3) the current pharmacological treatments for NAFLD that might also benefit or adversely affect risk of CVD.

Association between non alcoholic fatty liver disease, metabolic and vascular risk

BACKGROUND

Hepatic steatosis is a public health problem with increased incidence and prevalence OBJECTIVE: To determine whether the liver steatosis, as measured by the Fatty Liver Index (FLI), is related to metabolic risk and vascular factors and, if so, to identify the clinical-metabolic factor that explains the higher vascular risk.

METHODS

Cross-sectional study including a sample of 531 men who came to the University of Navarra Clinic Check-up Unit. The degree of steatosis was determined by the FLI. The metabolic risk was assessed using a scale based on determinations of HDL, LDL, triglycerides, blood glucose, HOMA-IR, neutrophil/lymphocyte index, and systolic blood pressure. The vascular risk was assessed by the presence of carotid and/or femoral atheromatous plaques. The dose-response association between FLI and both risks was analysed using non-parametric models (splines) and logistic regression.

RESULTS

The sample studied had a mean age of 52.70years, with 49.3% having an FLI ≥60, as well as 33.6% with metabolic syndrome, and 43.9% with carotid and/or femoral atheromatous plaques. The relationship between FLI and metabolic risk and vascular was linear (metabolic: non-linear P=.097; linear P<.001; vascular: non-linear P=1.000; linear P=.028). For every 10 units of increase in FLI, the odds of presenting with atheroma plaques increased by 9.7% (OR=1.097; 95% confidence interval 1.010-1.191). When adjusting for triglyceridaemia, the association disappeared (OR=1.001).

CONCLUSIONS

Patients with fatty liver disease had an increased metabolic and vascular risk. The increased vascular risk is associated with the triglyceride level. On a clinical level, this study suggests that these patients could benefit from treatment of hypertriglyceridaemia.

HDL-apoA-I kinetics in response to 16 wk of exercise training in men with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is characterized by low-circulating concentration of high-density lipoprotein cholesterol (HDL-C) and raised triacylglycerol (TAG). Exercise reduces hepatic fat content, improves insulin resistance and increases clearance of very-low-density lipoprotein-1 (VLDL₁). However, the effect of exercise on TAG and HDL-C metabolism is unknown. We randomized male participants to 16 wk of supervised, moderate-intensity aerobic exercise (n = 15), or conventional lifestyle advice (n = 12). Apolipoprotein A-I (apoA-I) and VLDL-TAG and apolipoprotein B (apoB) kinetics were investigated using stable isotopes (1-[¹³C]-leucine and 1,1,2,3,3-²H₅ glycerol) pre- and postintervention. Participants underwent MRI/spectroscopy to assess changes in visceral fat. Results are means ± SD. At baseline, there were no differences between exercise and control groups for age (52.4 ± 7.5 vs. 52.8 ± 10.3 yr), body mass index (BMI: 31.6 ± 3.2 vs. 31.7 ± 3.6 kg/m²), and waist circumference (109.3 ± 7.5 vs. 110.0 ± 13.6 cm). Percentage of liver fat was 23.8 (interquartile range 9.8-32.5%). Exercise reduced body weight (101.3 ± 10.2 to 97.9 ± 12.2 kg; P < 0.001) and hepatic fat content [from 19.6%, interquartile range (IQR) 14.6-36.1% to 8.9% (4.4-17.8%); P = 0.001] and increased the fraction HDL-C concentration (measured following ultracentrifugation) and apoA-I pool size with no change in the control group. However, plasma and VLDL₁-TAG concentrations and HDL-apoA-I fractional catabolic rate (FCR) and production rate (PR) did not change significantly with exercise. Both at baseline (all participants) and after exercise there was an inverse correlation between apoA-I pool size and VLDL-TAG and -apoB pool size. The modest effect of exercise on HDL metabolism may be explained by the lack of effect on plasma and VLDL₁-TAG.

LASS2 regulates hepatocyte steatosis by interacting with NDUFS2/OXPHOS related proteins

LAG1 longevity assurance homolog 2 (LASS2), a highly conserved transmembrane protein, has been reported to be associated with nonalcoholic fatty liver disease (NAFLD). However, the effect of LASS2 on energy homeostasis and its mechanism remains unknown. In this study, we found lower expression levels of LASS2 in the livers of mice with liver steatosis induced by a high-fat diet (HFD) and free fatty acids (FFAs)-treated hepatocytes. In FFAs-treated Hepa1-6 cells and mouse primary hepatocytes (MPHs), LASS2 overexpression significantly decreased intracellular lipid content compared with the control cells. LASS2 overexpression also significantly upregulated lipolysis-related proteins, such as ATGL and HSL, and inhibited lipogenesis-related proteins, such as SREBP1 and FAS. In addition, the phosphorylation levels of AMPK and ACC increased significantly. On the contrary, LASS2 knockdown in FFAs-treated hepatocytes aggravated lipid accumulation via facilitating lipogenesis and inhibiting lipolysis. Further, co-IP and LC-MS analysis found that LASS2 might interacted with NDUFS2 to inhibit lipogenesis. The production of mitochondrial reactive oxygen species (mtROS) may be related to the interaction between LASS2 and NDUFS2. Collectively, we are the first time to showed that LASS2 might promote the phosphorylation of AMPK via mtROS produced by interaction with NDUFS2/OXPHOS, thus inhibiting lipogenesis.

The Intricate Relationship between Type 2 Diabetes Mellitus (T2DM), Insulin Resistance (IR), and Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) remain as one of the most global problematic metabolic diseases with rapidly increasing prevalence and incidence. Epidemiological studies noted that T2DM patients have by two-fold increase to develop NAFLD, and vice versa. This complex and intricate association is supported and mediated by insulin resistance (IR). In this review, we discuss the NAFLD immunopathogenesis, connection with IR and T2DM, the role of screening and noninvasive tools, and mostly the impact of the current antidiabetic drugs on steatosis liver and new potential therapeutic targets.