Hepatokines as a Link between Obesity and Cardiovascular Diseases

Association between nonalcoholic fatty liver disease and left ventricular diastolic dysfunction: A 7-year retrospective cohort study of 3,380 adults using serial echocardiography

AIM

Left ventricular diastolic dysfunction (LVDD) has been observed in people with nonalcoholic fatty liver disease (NAFLD) in cross-sectional studies but the causal relationship is unclear. This study aimed to investigate the impact of NAFLD and the fibrotic progression of the disease on the development of LVDD, assessed by serial echocardiography, in a large population over a 7-year longitudinal setting.

METHODS

This retrospective cohort study included the data of 3,380 subjects from a medical health check-up program. We defined subjects having NAFLD by abdominal ultrasonography and assessed significant liver fibrosis by the aspartate transaminase (AST) to platelet ratio index (APRI), the NAFLD fibrosis score (NFS), and the fibrosis-4 (FIB-4) index. LVDD was defined using serial echocardiography. A parametric Cox proportional hazards model was used.

RESULTS

During 11,327 person-years of follow-up, there were 560 (16.0 %) incident cases of LVDD. After adjustment for multiple risk factors, subjects with NAFLD showed an increased adjusted hazard ratio (aHR) of 1.21 (95 % confidence interval [CI]=1.02-1.43) for incident LVDD compared to those without. The risk of LV diastolic dysfunction increased progressively with increasing degree of hepatic steatosis (P< 0.001). Compared to subjects without NAFLD, the multivariable-aHR (95 % CI) for LVDD in subjects with APRI < 0.5 and APRI ≥ 0.5 were 1.20 (1.01-1.42) and 1.36 (0.90-2.06), respectively (P= 0.036), while other fibrosis prediction models (NFS and FIB-4 index) showed insignificant results.

CONCLUSIONS

This study demonstrated that NAFLD was associated with an increased risk of LVDD in a large cohort. More severe forms of hepatic steatosis and/or significant liver fibrosis may increase the risk of developing LVDD.

From Beats to Metabolism: the Heart at the Core of Interorgan Metabolic Cross Talk

The heart, once considered a mere blood pump, is now recognized as a multifunctional metabolic and endocrine organ. Its function is tightly regulated by various metabolic processes, at the same time it serves as an endocrine organ, secreting bioactive molecules that impact systemic metabolism. In recent years, research has shed light on the intricate interplay between the heart and other metabolic organs, such as adipose tissue, liver, and skeletal muscle. The metabolic flexibility of the heart and its ability to switch between different energy substrates play a crucial role in maintaining cardiac function and overall metabolic homeostasis. Gaining a comprehensive understanding of how metabolic disorders disrupt cardiac metabolism is crucial, as it plays a pivotal role in the development and progression of cardiac diseases. The emerging understanding of the heart as a metabolic and endocrine organ highlights its essential contribution to whole body metabolic regulation and offers new insights into the pathogenesis of metabolic diseases, such as obesity, diabetes, and cardiovascular disorders. In this review, we provide an in-depth exploration of the heart's metabolic and endocrine functions, emphasizing its role in systemic metabolism and the interplay between the heart and other metabolic organs. Furthermore, emerging evidence suggests a correlation between heart disease and other conditions such as aging and cancer, indicating that the metabolic dysfunction observed in these conditions may share common underlying mechanisms. By unraveling the complex mechanisms underlying cardiac metabolism, we aim to contribute to the development of novel therapeutic strategies for metabolic diseases and improve overall cardiovascular health.

Exerkines and cardiometabolic benefits of exercise: from bench to clinic

Regular exercise has both immediate and long-lasting benefits on cardiometabolic health, and has been recommended as a cornerstone of treatment in the management of diabetes and cardiovascular conditions. Exerkines, which are defined as humoral factors responsive to acute or chronic exercise, have emerged as important players conferring some of the multiple cardiometabolic benefits of exercise. Over the past decades, hundreds of exerkines released from skeletal muscle, heart, liver, adipose tissue, brain, and gut have been identified, and several exerkines (such as FGF21, IL-6, and adiponectin) have been exploited therapeutically as exercise mimetics for the treatment of various metabolic and cardiovascular diseases. Recent advances in metagenomics have led to the identification of gut microbiota, a so-called "hidden" metabolic organ, as an additional class of exerkines determining the efficacy of exercise in diabetes prevention, cardiac protection, and exercise performance. Furthermore, multiomics-based studies have shown the feasibility of using baseline exerkine signatures to predict individual responses to exercise with respect to metabolic and cardiorespiratory health. This review aims to explore the molecular pathways whereby exerkine networks mediate the cardiometabolic adaptations to exercise by fine-tuning inter-organ crosstalk, and discuss the roadmaps for translating exerkine-based discovery into the therapeutic application and personalized medicine in the management of the cardiometabolic disease.

The liver-heart axis in patients with severe obesity: The association between liver fibrosis and chronic myocardial injury may be explained by shared risk factors of cardiovascular disease

BACKGROUND

Severe obesity is associated with increased risk of non-alcoholic fatty liver disease and cardiovascular disease. We hypothesized that liver fibrosis as quantified by the Enhanced Liver Fibrosis (ELF) test would be predictive of myocardial injury and fibrosis, expressed by higher concentrations of cardiac troponin T and I measured by high-sensitivity assays (hs-cTnT and hs-cTnI, respectively).

MATERIAL AND METHODS

We performed cross-sectional analyses of baseline data from 136 patients (mean age 45 years, 38 % male) with severe obesity participating in the non-randomized clinical trial Prevention of Coronary Heart Disease in Morbidly Obese Patients (ClinicalTrials.gov NCT00626964). Associations between ELF scores, hs-cTnT, and hs-cTnI concentrations were assessed using linear regression analysis.

RESULTS

ELF scores were associated with hs-cTnT in the unadjusted model (B 0.381, 95 % Confidence Interval [CI] 0.247, 0.514), but the association was attenuated upon adjustment for potential confounders (B -0.031, 95 % CI -0.155, 0.093). Similarly, for hs-cTnI, an observed association with ELF scores in the unadjusted model was attenuated upon adjustment for potential confounders ((B 0.432, 95 % CI 0.179, 0.685) and (B 0.069, 95 % CI -0.230, 0.367), respectively). Age, sex, hypertension, and estimated glomerular filtration rate were amongst the shared predictors of ELF score, hs-cTnT, and hs-cTnI that provided the univariable models with the highest R-squared and lowest Akaike Information Criterion values.

CONCLUSIONS

Contrary to our hypothesis, ELF score did not predict myocardial injury and fibrosis, but we rather demonstrated an association between liver fibrosis and myocardial injury and fibrosis may be explained by shared risk factors of cardiovascular disease.

Reversal of nonalcoholic fatty liver disease reduces the risk of cardiovascular disease among Korean

Nonalcoholic fatty liver disease (NAFLD) is considered an independent risk factor for the development of cardiovascular disease. However, the association between changes in NAFLD status and the risk of cardiovascular disease (CVD) remains uncertain. Starting January 1, 2013, participants were followed until the occurrence of CVD event, death, or December 31, 2020. This was a population-based cohort study that included data from adults aged ≥ 20, who underwent 2 consecutive health screenings from 2009 to 2012. NAFLD was defined as a Fatty Liver Index ≥ 60 at each screening. The primary endpoint was a CVD event, which encompassed ischemic heart disease and cerebrovascular disease. The association between changes in NAFLD status and the risk of CVD was determined using multivariable Cox proportional hazards regression. This cohort comprised 4656,305 adults with a median age of 53 years. During 36,396,968 person-years of follow-up, 238,933 (5.1%) CVD events were observed. Compared to patients with no NAFLD at both screenings, patients who developed NAFLD at the second screening exhibited an increased risk of CVD (adjusted hazard ratio, 1.15; 95% confidence interval, 1.13-1.17). In contrast, individuals who recovered from NAFLD at the second screening demonstrated a reduced CVD risk compared to those with persistent NAFLD (adjusted hazard ratio, 0.91; 95% confidence interval, 0.90-0.92). The reversal of NAFLD is associated with a reduced risk of CVD. Therefore, focusing on NAFLD treatment could serve as a clinical target for lowering CVD risk.

"Alphabet" Selenoproteins: Implications in Pathology

Selenoproteins are a group of proteins containing selenium in the form of selenocysteine (Sec, U) as the 21st amino acid coded in the genetic code. Their synthesis depends on dietary selenium uptake and a common set of cofactors. Selenoproteins accomplish diverse roles in the body and cell processes by acting, for example, as antioxidants, modulators of the immune function, and detoxification agents for heavy metals, other xenobiotics, and key compounds in thyroid hormone metabolism. Although the functions of all this protein family are still unknown, several disorders in their structure, activity, or expression have been described by researchers. They concluded that selenium or cofactors deficiency, on the one hand, or the polymorphism in selenoproteins genes and synthesis, on the other hand, are involved in a large variety of pathological conditions, including type 2 diabetes, cardiovascular, muscular, oncological, hepatic, endocrine, immuno-inflammatory, and neurodegenerative diseases. This review focuses on the specific roles of selenoproteins named after letters of the alphabet in medicine, which are less known than the rest, regarding their implications in the pathological processes of several prevalent diseases and disease prevention.

Effects of treatment of non-alcoholic fatty liver disease on heart failure with preserved ejection fraction

In the past few decades, non-alcoholic fatty liver disease (NAFLD) and heart failure with preserved ejection fraction (HFpEF) have become the most common chronic liver disease and the main form of heart failure (HF), respectively. NAFLD is closely associated with HFpEF by sharing common risk factors and/or by boosting systemic inflammation, releasing other secretory factors, and having an expansion of epicardial adipose tissue (EAT). Therefore, the treatments of NAFLD may also affect the development and prognosis of HFpEF. However, no specific drugs for NAFLD have been approved by the Food and Drug Administration (FDA) and some non-specific treatments for NAFLD are applied in the clinic. Currently, the treatments of NAFLD can be divided into non-pharmacological and pharmacological treatments. Non-pharmacological treatments mainly include dietary intervention, weight loss by exercise, caloric restriction, and bariatric surgery. Pharmacological treatments mainly include administering statins, thiazolidinediones, glucagon-like peptide-1 receptor agonists, sodium-glucose cotransporter 2 inhibitors, and metformin. This review will mainly focus on analyzing how these treatments may affect the development and prognosis of HFpEF.

Fetuin-A and Its Association with Anthropometric, Atherogenic, and Biochemical Parameters and Indices among Women with Polycystic Ovary Syndrome

Background: Polycystic ovary syndrome (PCOS) contributes to metabolic and endocrine complications for women of reproductive age. We set out to assess the relationship between fetuin-A and anthropometric parameters, anthropometric indices, body composition, and atherogenic indices, as well as carbohydrate and lipid profile in women with polycystic ovary syndrome (PCOS). Methods. The study included 49 women with PCOS, aged between 18 and 39 years. All patients were tested for fetuin-A, fasting glucose and insulin, and lipid parameters, after oral-glucose administration were done. All of them underwent anthropometric measurements and body composition analyses such as BMI (Body Mass Index), WHR (Waist to Hip Ratio), WHtR (Waist to Height Ratio), BAI (Body Adiposity Index), VAI (Visceral Adiposity Index), LAP (Lipid Accumulation Product), BRI (Body Roundness Index), ABSI (A Body Shape Index), ABSI z-core (ABSI with added mortality risk in correlation with age and gender), AIP (Atherogenic Risk of Plasma), AC (Atherogenic Coefficient), Castelli risk index-I, and Castelli risk index-II. Results: Obesity was diagnosed in 18 patients (36.7%) based on BMI index and 7 patients (14.3%) based on BAI index. Significantly increased risk of metabolic complications was observed among 26 patients (53.1%) based on waist circumferences. Based on VAI index, risk of metabolic disease was observed among 17 women (34.7%). Dyslipidemia such as hypercholesterolemia, hypertriglyceridemia, and mixed hyperlipidemia was detected among 14 patients (28.6%), and insulin resistance was observed among 29 (59.2%). There was a positive correlation between fetuin-A and total cholesterol (r = 0.30, p = 0.0034). There was no statistically significant correlation between fetuin-A and all of the anthropometric measurements and anthropometric indices, atherogenic indices, and other biochemical parameters. Conclusion: Fetuin-A correlates with hypercholesterolemia. It is necessary to conduct further research regarding the relationship between fetuin-A concentrations and body composition, anthropometric indices, and metabolic disorders in women with PCOS. Surprisingly, the effects of concentration of fetuin-A and anthropometric indices (BAI, VAI, LAP, ABSI, ABSI z-core) in woman with PCOS have not been closely examined. Future studies that take these variables into account will need to be undertaken. More information on the relationship between fetuin-A concentrations and anthropometric indices would aid us in establishing a greater degree of accuracy on this matter.

A coagulation factor moonlights in the heart

Liver-derived coagulation factor XI protects the heart from failure.

Obesity is an important determinant of severity in newly defined metabolic dysfunction-associated fatty liver disease

BACKGROUND

The recently proposed definition of metabolic dysfunction-associated fatty liver disease (MAFLD) is based on the co-existence of hepatic steatosis with other metabolic disorders, including obesity and metabolic risk abnormalities such as hyperglycemia, high blood pressure and dyslipidemia. This study aimed to assess MAFLD severity according to the presence of metabolic abnormalities and obesity.

METHODS

Using transient elastography, hepatic steatosis and fibrosis severity were assessed by measuring the controlled attenuation parameter and liver stiffness measurement. A total of 1163 patients with MAFLD were categorized into the following four groups according to metabolic risk abnormalities and obesity presence: non-obese without metabolic risk abnormality group (Group 1; reference group); non-obese with metabolic risk abnormality group (Group 2); obese without metabolic risk abnormality group (Group 3); and obese with metabolic risk abnormality group (Group 4). A multiple logistic regression analysis was performed to determine severe hepatic steatosis and fibrosis risk in each group in both unadjusted and adjusted models.

RESULTS

In the adjusted model, the odds ratios (ORs) [95% confidence interval (CI)] for severe hepatic steatosis in Groups 2, 3, and 4 were 1.07 (0.61-1.88), 2.43 (1.44-4.08), and 4.07 (2.56-6.48), respectively (P_trend < 0.001). For liver fibrosis, compared with Group 1, Group 2 showed no significant increases in OR, whereas Groups 3 and 4 (obese groups) showed significant increases (OR = 4.70, 95% CI: 1.24-17.82 and OR = 6.43, 95% CI: 1.88-22.02, respectively).

CONCLUSIONS

Obesity, rather than metabolic abnormality, is the principal determinant of severe hepatic steatosis and fibrosis in patients with MAFLD.

AMP activated kinase negatively regulates hepatic Fetuin-A via p38 MAPK-C/EBPβ/E3 Ubiquitin Ligase Signaling pathway

Fetuin-A (Fet-A) is a liver-secreted phosphorylated protein, known to impair insulin signaling, which has been shown to be associated with obesity, insulin resistance, and incident diabetes. Fet-A interacts with the insulin-stimulated insulin receptor (IR) and inhibits IR tyrosine kinase activity and glucose uptake. It has been shown that high glucose increases Fet-A expression through the ERK1/2 signaling pathway. However, factors that downregulate Fet-A expression and their potential mechanisms are unclear. We examined the effect of AMP-activated protein kinase (AMPK) on high-glucose induced Fet-A expression in HepG2 cells, Hep3B cells and primary rat hepatocytes. High glucose increased Fet-A and phosphorylated (Ser312) fetuin-A (pFet-A) expression, which are known to impair insulin signaling. AICAR-induced AMPK activation significantly down-regulated high glucose-induced Fet-A expression and secretion of pFet-A while treatment with Compound C (AMPK inhibitor), SB202190 (p38 MAPK inhibitor) or p38 MAPK siRNA transfection prevented AICAR-induced downregulation of Fet-A expression. In addition, activation of p38 MAPK, by anisomycin, decreased the hepatic expression of Fet-A. Further, we our studies have shown that short-term effect of AICAR-treatment on Fet-A expression was mediated by proteosomal degradation, and long-term treatment of AICAR was associated with decrease in hepatic expression of C/EBP beta, an important transcription factor involved in the regulation of Fet-A. Taken together, our studies implicate a critical role for AMPK-p38 MAPK-C/EBPb-ubiquitin-proteosomal axis in the regulation of the expression of hepatic Fet-A.

Hepatic PTEN Signaling Regulates Systemic Metabolic Homeostasis through Hepatokines-Mediated Liver-to-Peripheral Organs Crosstalk

Liver-derived circulating factors deeply affect the metabolism of distal organs. Herein, we took advantage of the hepatocyte-specific PTEN knockout mice (LPTENKO), a model of hepatic steatosis associated with increased muscle insulin sensitivity and decreased adiposity, to identify potential secreted hepatic factors improving metabolic homeostasis. Our results indicated that protein factors, rather than specific metabolites, released by PTEN-deficient hepatocytes trigger an improved muscle insulin sensitivity and a decreased adiposity in LPTENKO. In this regard, a proteomic analysis of conditioned media from PTEN-deficient primary hepatocytes identified seven hepatokines whose expression/secretion was deregulated. Distinct expression patterns of these hepatokines were observed in hepatic tissues from human/mouse with NAFLD. The expression of specific factors was regulated by the PTEN/PI3K, PPAR or AMPK signaling pathways and/or modulated by classical antidiabetic drugs. Finally, loss-of-function studies identified FGF21 and the triad AHSG, ANGPTL4 and LECT2 as key regulators of insulin sensitivity in muscle cells and in adipocytes biogenesis, respectively. These data indicate that hepatic PTEN deficiency and steatosis alter the expression/secretion of hepatokines regulating insulin sensitivity in muscles and the lipid metabolism in adipose tissue. These hepatokines could represent potential therapeutic targets to treat obesity and insulin resistance.

Extent and features of liver steatosis in vitro pave the way to endothelial dysfunction without physical cell-to-cell contact

BACKGROUND AND AIMS

Several chronic multifactorial diseases originate from energy unbalance between food intake and body energy expenditure, including non-alcoholic fatty liver disease (NAFLD), diabetes, and cardiovascular disorders. Vascular endothelium plays a central role in body homeostasis, and NAFLD is often associated with endothelial dysfunction (ED), the first step in atherosclerosis. Both sugars and fatty acids (FAs) are fuel sources for energy production, but their excess leads to liver steatosis which may trigger ED through a network of mechanisms which need to be clarified. Here, we investigated the crosstalk pathways between in vitro cultured steatotic hepatocytes (FaO) and endothelial cells (HECV) being mediated by soluble factors.

METHODS AND RESULTS

We employed the conditioned medium approach to test how different extent and features of hepatic steatosis distinctively affect endothelium leading to ED. The steatogenic media collected from steatotic hepatocytes were characterized by high triglyceride content and led to lipid accumulation and fat-dependent dysfunction in HECV cells. We found a parallelism between (i) extent of hepatocyte steatosis and level of lipid accumulation in HECV cells; (ii) type of hepatocyte steatosis (with macro- or microvesicular LDs) and extent of oxidative stress, lipid peroxidation, nitric oxide release and expression of ED markers in HECV cells.

CONCLUSIONS

The present findings seem to suggest that, in addition to triglycerides, other soluble mediators should be released by steatotic hepatocytes and may influence lipid accumulation and function of HECV cells. Further studies need to depict the exact profile of soluble factors involved in steatotic hepatocyte-endothelium crosstalk.

Investigating Fetuin-A and Paraoxonase-1 Activity as Markers in Polycystic Ovary Syndrome Based on Body Mass Index: A Prospective Case-Control Study

Introduction Polycystic ovary syndrome (PCOS) may have an increased risk for the development of systemic and metabolic pathogenesis such as cardiovascular diseases, insulin resistance (IR), diabetes mellitus (DM) and dyslipidemia. However, there is no reliable marker to show the relation. Fetuin-A is an adipokine whereas paraoxonase-1 (PON-1) is a high-density lipoprotein-linked enzyme to demonstrate oxidative stress. This study aimed to evaluate serum fetuin-A and PON-1 levels in infertile PCOS women based on body mass index (BMI). Methods A prospective case-control study in a university setting was designed. A total of 88 patients admitted to the Giresun University Faculty of Medicine Gynecology Clinic between February and April 2021 were included in the study. The subjects were divided as follows: PCOS-low-BMI (BMI≤25) vs. Controls-low-BMI (BMI≤25) and PCOS-high-BMI (BMI>25) vs. Controls-high-BMI (BMI>25). Those who had at least two criteria of the 2003 Rotterdam Consensus were diagnosed with PCOS. Serum fetuin-A and PON-1 levels were compared. Results The mean levels of fetuin-A were not significantly different in the groups (p=0.955). Serum PON-1 levels were lower in the PCOS group (109.1±61.4 vs. 140.1±80.0; p=0.040), but it lost significance with adjusted values for covariants as age and BMI. Although PON-1 was not significantly different in the PCOS group of BMI<25 kg/m² subgroup, it was significantly lower in the PCOS group of BMI≥25 kg/m² subgroup (p=0.820 vs. p=0.048). Conclusion Serum fetuin-A activity did not differ with PCOS. Serum PON-1 might be a promising and research-worthy marker, especially for obese PCOS patients.

Nonalcoholic Fatty Liver Disease (NAFLD). Mitochondria as Players and Targets of Therapies?

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and represents the hepatic expression of several metabolic abnormalities of high epidemiologic relevance. Fat accumulation in the hepatocytes results in cellular fragility and risk of progression toward necroinflammation, i.e., nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Several pathways contribute to fat accumulation and damage in the liver and can also involve the mitochondria, whose functional integrity is essential to maintain liver bioenergetics. In NAFLD/NASH, both structural and functional mitochondrial abnormalities occur and can involve mitochondrial electron transport chain, decreased mitochondrial β-oxidation of free fatty acids, excessive generation of reactive oxygen species, and lipid peroxidation. NASH is a major target of therapy, but there is no established single or combined treatment so far. Notably, translational and clinical studies point to mitochondria as future therapeutic targets in NAFLD since the prevention of mitochondrial damage could improve liver bioenergetics.

Hepatocardiac or Cardiohepatic Interaction: From Traditional Chinese Medicine to Western Medicine

There is a close relationship between the liver and heart based on "zang-xiang theory," "five-element theory," and "five-zang/five-viscus/five-organ correlation theory" in the theoretical system of Traditional Chinese Medicine (TCM). Moreover, with the development of molecular biology, genetics, immunology, and others, the Modern Medicine indicates the existence of the essential interorgan communication between the liver and heart (the heart and liver). Anatomically and physiologically, the liver and heart are connected with each other primarily via "blood circulation." Pathologically, liver diseases can affect the heart; for example, patients with end-stage liver disease (liver failure/cirrhosis) may develop into "cirrhotic cardiomyopathy," and nonalcoholic fatty liver disease (NAFLD) may promote the development of cardiovascular diseases via multiple molecular mechanisms. In contrast, heart diseases can affect the liver, heart failure may lead to cardiogenic hypoxic hepatitis and cardiac cirrhosis, and atrial fibrillation (AF) markedly alters the hepatic gene expression profile and induces AF-related hypercoagulation. The heart can also influence liver metabolism via certain nonsecretory cardiac gene-mediated multiple signals. Moreover, organokines are essential mediators of organ crosstalk, e.g., cardiomyokines link the heart to the liver, while hepatokines link the liver to the heart. Therefore, both TCM and Western Medicine, and both the basic research studies and the clinical practices, all indicate that there exist essential "heart-liver axes" and "liver-heart axes." To investigate the organ interactions between the liver and heart (the heart and liver) will help us broaden and deepen our understanding of the pathogenesis of both liver and heart diseases, thus improving the strategies of prevention and treatment in the future.

Mitochondrial Dysfunction is a Key Pathway that Links Saturated Fat Intake to the Development and Progression of NAFLD

Non-Alcoholic fatty liver disease (NAFLD) is the most common form of liver disease and is characterized by fat accumulation in the liver. Hypercaloric diets generally increase hepatic fat accumulation, whereas hypocaloric diets decrease liver fat content. In addition, there is evidence to suggest that moderate amounts of unsaturated fatty acids seems to be protective for the development of a fatty liver, while consumption of saturated fatty acids (SFA) appears to predispose toward hepatic steatosis. Recent studies highlight a key role for mitochondrial dysfunction in the development and progression of NAFLD. It is proposed that changes in mitochondrial structure and function are key mechanisms by which SFA lead to the development and progression of NAFLD. In this review, it is described how SFA intake is associated with liver steatosis and decreases the efficiency of the respiratory transport chain. This results in the production of reactive oxygen species and damage to nearby structures, eventually leading to inflammation, apoptosis, and scarring of the liver. Furthermore, studies demonstrating that SFA intake affects the composition of mitochondrial membranes are presented, and this process accelerates the progression of NAFLD. It is likely that events are intertwined and reinforce each other, leading to a constant deterioration in health.

Elevated blood pressure, cardiometabolic risk and target organ damage in youth with overweight and obesity

BACKGROUND AND AIM

To compare cardiometabolic risk profile and preclinical signs of target organ damage in youth with normal and elevated blood pressure (BP), according to the American Academy of Pediatrics (AAP) guidelines.

METHODS AND RESULTS

This cross-sectional multicenter study included 2739 youth (5-17 year-old; 170 normal-weight, 610 overweight and 1959 with obesity) defined non hypertensive by the AAP guidelines. Anthropometric, biochemical and liver ultrasound data were available in the whole population; carotid artery ultrasound and echocardiographic assessments were available respectively in 427 and 264 youth. Elevated BP was defined as BP ≥ 90th to <95th percentile for age, gender and height in children or BP ≥ 120/80 to <130/80 in adolescents. The overall prevalence of elevated BP was 18.3%, and significantly increased from normal-weight to obese youth. Young people with elevated BP showed higher levels of body mass index (BMI), insulin resistance and a higher prevalence of liver steatosis (45% vs 36%, p < 0.0001) than normotensive youth, whilst they did not differ for the other cardiometabolic risk factors, neither for carotid intima media thickness or left ventricular mass. Compared with normotensive youth, individuals with elevated BP had an odds ratio (95%Cl) of 3.60 (2.00-6.46) for overweight/obesity, 1.46 (1.19-1.78) for insulin-resistance and 1.45 (1.19-1.77) for liver steatosis, controlling for centers, age and prepubertal stage. The odds for insulin resistance and liver steatosis persisted elevated after correction for BMI-SDS.

CONCLUSION

Compared to normotensive youth, elevated BP is associated with increased BMI, insulin resistance and liver steatosis, without significant target organ damage.

The intrinsic and extrinsic elements regulating inflammation

Inflammation is a sophisticated biological tissue response to both extrinsic and intrinsic stimuli. Although the pathological aspects of inflammation are well appreciated, there are still rooms for understanding the physiological functions of the inflammation. Recent studies have focused on mechanisms, context and the role of physiological inflammation. Besides, there have been progress in the comprehension of commensal microbiota, immunometabolism, cancer and intracellular signaling events' roles that impact on the regulation of inflammation. Despite the fact that inflammatory responses are vital through tissue damage, understanding the mechanisms to turn off the finished or unnecessary inflammation is crucial for restoring homeostasis. Inflammation seems to be a smart process that acts like two edges of a sword, meaning that it has both protective and deleterious consequences. Knowing both edges and the regulation processes will help the future understanding and therapy for various diseases.

Serum Fetuin-A levels are increased and associated with insulin resistance in women with polycystic ovary syndrome

BACKGROUND

Insulin resistance (IR) is a common characteristic of women with polycystic ovary syndrome (PCOS). It has been reported that circulating Fetuin-A levels were associated with IR and type 2 diabetes mellitus (T2DM). However, previous reports were inconsistent.

METHODS

Two hundred seven subjects were screened for PCOS according to the diagnostic guideline of the Rotterdam consensus criterion. Serum Fetuin-A levels were measured using an ELISA kit. An independent t-test or Nonparametric test was used to detect differences between PCOS and control groups. Spearman's correlation analysis was used to examine the association of the serum Fetuin-A with other parameters.

RESULTS

Our findings showed that circulating Fetuin-A concentration ranged from 196.6 to 418.2 μg/L for most women without PCOS (95%). Women with PCOS had higher circulating Fetuin-A levels than healthy women (437.9 ± 119.3 vs. 313.8 ± 60.5 μg/L; p <  0.01). Serum Fetuin-A was positively correlated with BMI, WHR, TG, TC, LDL-C, HOMA-IR, LH, T, and DHEA-S. Multivariate regression analysis showed that WHR, TG, HOMA-IR, and DHEA-S were independent predictors of the levels of circulating Fetuin-A. Binary logistic regression revealed that serum Fetuin-A was associated with the occurrence of PCOS. In addition, our ROC curve analysis found that the cutoff values for Fetuin-A to predict PCOS and IR were 366.3 and 412.6 μg/L.

CONCLUSION

Blood Fetuin-A may be a useful biomarker for screening women for PCOS and IR.

Association of Fetuin-B with Subclinical Atherosclerosis in Obese Chinese Adults

Aim: We aimed to explore the independent associations of serum Fetuin-B and common genetic variants in FETUB locus with subclinical atherosclerosis.

Methods: A cross-sectional study of 1,140 obese adults, who underwent serum Fetuin-B testing, hepatic ultrasonography scanning, genotyping on four tagging single nucleotide polymorphisms (SNPs) in FETUB locus and atherosclerosis detection, was conducted in Xiamen, China.

Results: Increasing tertiles of brachial ankle pulse wave velocity (ba-PWV) were significantly associated with higher prevalence of nonalcoholic fatty liver disease (NAFLD) (48.8%, 61.5%, and 70.5% for tertiles of 1–3, respectively, p < 0.001) and serum Fetuin-B (3.85 ± 1.39, 4.09 ± 1.40, and 4.27 ± 1.46 µg/ml, p = 0.047). Multivariable linear regression analyses with adjustment for potential confounding factors, even NAFLD per se, showed that serum Fetuin-B were significantly and positively associated with ba-PWV, with standardized regression coefficients (β) ranging from 0.055 to 0.075 (all p-values < 0.05) in different models. However, the significant relationship between serum Fetuin-B and ba-PWV disappeared with further adjustment for insulin resistance. Serum Fetuin-B was not significantly associated with ankle-brachial index (ABI). All genotypes of the four tested FETUB tagging SNPs were not significantly associated with either ba-PWV or ABI with adjustment for potential confounding factors

Conclusion: Serum Fetuin-B was positively associated with ba-PWV and may link liver fat accumulation to subclinical atherosclerosis via insulin resistance.

Metabolic Inflammation-A Role for Hepatic Inflammatory Pathways as Drivers of Comorbidities in Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease (NAFLD) is a global and growing health concern. Emerging evidence points toward metabolic inflammation as a key process in the fatty liver that contributes to multiorgan morbidity. Key extrahepatic comorbidities that are influenced by NAFLD are type 2 diabetes, cardiovascular disease, and impaired neurocognitive function. Importantly, the presence of nonalcoholic steatohepatitis and advanced hepatic fibrosis increase the risk for systemic comorbidity in NAFLD. Although the precise nature of the crosstalk between the liver and other organs has not yet been fully elucidated, there is emerging evidence that metabolic inflammation-in part, emanating from the fatty liver-is the engine that drives cellular dysfunction, cell death, and deleterious remodeling within various body tissues. This review describes several inflammatory pathways and mediators that have been implicated as links between NAFLD and type 2 diabetes, cardiovascular disease, and neurocognitive decline.

A Close Relationship between Non-Alcoholic Fatty Liver Disease Marker and New-Onset Hypertension in Healthy Korean Adults

Background and Objectives

Nonalcoholic fatty liver disease (NAFLD) is an excessive accumulation of fat into the liver as a result of increased inflammation and insulin resistance. Although there can be common pathogenic mechanisms for NAFLD and hypertension associated with the development of cardiovascular diseases, little data are showing the association between NAFLD and hypertension in a large-scale cohort study. Thus, we evaluated the ability of the fatty liver index (FLI), a surrogate marker of NAFLD, to predict the development of hypertension in healthy individuals.

Methods

We included 334,280 healthy individuals without known comorbidities who underwent the National Health check-ups in South Korea from 2009 to 2014. The association between the FLI and hypertension was analyzed using multivariate Cox proportional-hazards models.

Results

During a median of 5.2 years' follow-up, 24,678 subjects (7.4%) had new-onset hypertension. We categorized total subjects into quartile groups according to FLI (range: Q1, 0–4.9; Q2, 5.0–12.5; Q3, 12.6–31.0; and Q4, >31.0). The incidence of hypertension was higher in subjects with the highest FLI than in those with the lowest FLI (Q4, 9,968 [11.9%] vs. Q1, 2,277 [2.7%]; p<0.001). There was a significant correlation between the highest FLI and an increased risk of new-onset hypertension (adjusted hazard ratio between Q4 and Q1, 2.330; 95% confidence interval, 2.218–2.448; p<0.001). FLI was significantly associated with an increased risk of new-onset hypertension regardless of baseline characteristics.

Conclusions

Higher FLI was independently associated with increased risk of hypertension in a healthy Korean population.

Liver governs adipose remodelling via extracellular vesicles in response to lipid overload

Lipid overload results in lipid redistribution among metabolic organs such as liver, adipose, and muscle; therefore, the interplay between liver and other organs is important to maintain lipid homeostasis. Here, we show that liver responds to lipid overload first and sends hepatocyte-derived extracellular vesicles (EVs) targeting adipocytes to regulate adipogenesis and lipogenesis. Geranylgeranyl diphosphate synthase (Ggpps) expression in liver is enhanced by lipid overload and regulates EV secretion through Rab27A geranylgeranylation. Consistently, liver-specific Ggpps deficient mice have reduced fat adipose deposition. The levels of several EV-derived miRNAs in the plasma of non-alcoholic fatty liver disease (NAFLD) patients are positively correlated with body mass index (BMI), and these miRNAs enhance adipocyte lipid accumulation. Thus, we highlight an inter-organ mechanism whereby the liver senses different metabolic states and sends corresponding signals to remodel adipose tissue to adapt to metabolic changes in response to lipid overload.

Inter-organ cross-talk in metabolic syndrome

Maintenance of systemic homeostasis and the response to nutritional and environmental challenges require the coordination of multiple organs and tissues. To respond to various metabolic demands, higher organisms have developed a system of inter-organ communication through which one tissue can affect metabolic pathways in a distant tissue. Dysregulation of these lines of communication contributes to human pathologies, including obesity, diabetes, liver disease and atherosclerosis. In recent years, technical advances such as data-driven bioinformatics, proteomics and lipidomics have enabled efforts to understand the complexity of systemic metabolic cross-talk and its underlying mechanisms. Here, we provide an overview of inter-organ signals and their roles in metabolic control, and highlight recent discoveries in the field. We review peptide, small-molecule and lipid mediators secreted by metabolic tissues, as well as the role of the central nervous system in orchestrating peripheral metabolic functions. Finally, we discuss the contributions of inter-organ signalling networks to the features of metabolic syndrome.

Current and Future Nutritional Strategies to Modulate Inflammatory Dynamics in Metabolic Disorders

Obesity, type 2 diabetes, and other metabolic disorders have a large impact on global health, especially in Western countries. An important hallmark of metabolic disorders is chronic low-grade inflammation. A key player in chronic low-grade inflammation is dysmetabolism, which is defined as the inability to keep homeostasis resulting in loss of lipid control, oxidative stress, inflammation, and insulin resistance. Although often not yet detectable in the circulation, chronic low-grade inflammation can be present in one or multiple organs. The response to a metabolic challenge containing lipids may magnify dysfunctionalities at the tissue level, causing an overflow of inflammatory markers into the circulation and hence allow detection of early low-grade inflammation. Here, we summarize the evidence of successful application of metabolic challenge tests in type 2 diabetes, metabolic syndrome, obesity, and unhealthy aging. We also review how metabolic challenge tests have been successfully applied to evaluate nutritional intervention effects, including an "anti-inflammatory" mixture, dark chocolate, whole grain wheat and overfeeding. Additionally, we elaborate on future strategies to (re)gain inflammatory flexibility. Through epigenetic and metabolic regulation, the inflammatory response may be trained by regular mild and metabolic triggers, which can be understood from the perspective of trained immunity, hormesis and pro-resolution. New strategies to optimize dynamics of inflammation may become available.

Fibroblast growth factor 21 in lipid metabolism and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases in several developed countries, ranging from simple non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH) and cirrhosis. Currently, NAFLD has been confirmed to be associated with dyslipidemia, insulin resistance, and pre-diabetes, which are always grouped together as metabolic syndrome. Fibroblast growth factor 21 (FGF21) plays an important role in liver pathophysiology with multiple metabolic functions. Accumulating evidence has shown that FGF21 could directly modulate lipid metabolism and reduce lipid accumulation in hepatocytes through an insulin-independent pathway, thus suppressing the pathogenesis of NAFLD. Furthermore, treatment with FGF21 could obviously reverse NAFLD and synergistically alleviate obesity and counteract insulin resistance. In this review, we summarize the current knowledge of FGF21 and the evidence of FGF21 as an important regulator in hepatic lipid metabolism. The mechanisms by which FGF21 affects the pathogenesis of NAFLD would also be proposed for the further understanding of FGF21.

Leukocyte cell-derived chemotaxin 2 inhibits development of atherosclerosis in mice

Leukocyte cell-derived chemotaxin 2 (LECT2), a multifunctional hepatokine, is involved in many pathological conditions. However, its role in atherosclerosis remains undefined. In this study, we administered vehicle or LECT2 to male Apoe^-/- mice fed a Western diet for 15 weeks. Atherosclerotic lesions were visualized and quantified with Oil-red O and hematoxylin staining. The mRNA expression levels of MCP-1, MMP-1, IL-8, IL-1β, and TNF-α were analyzed by quantitative real-time polymerase chain reaction. Serum TNF-α, IL-1β, IL-8, MCP-1, and MMP-1 concentrations were measured by enzyme-linked immunosorbent assay. CD68, CD31, and α-SMA, markers of macrophages, endothelial cells, and smooth muscle cells, respectively, were detected by immunostaining. Results showed that LECT2 reduced total cholesterol and low-density lipoprotein concentrations in serum and inhibited the development of atherosclerotic lesions, accompanied by reductions in inflammatory cytokines and lower MCP-1, MMP-1, TNF-α, IL-8, and IL-1β mRNA abundance. Furthermore, LECT2 decreased CD68, but increased α-SMA in atherosclerotic lesions, suggesting an increase in smooth muscle cells and reduction in macrophages. In summary, LECT2 inhibited the development of atherosclerosis in mice, accompanied by reduced serum total cholesterol concentration and lower inflammatory responses.

Fetuin-A is also an adipokine

Fetuin-A (FetA), which impairs insulin action is considered classically as a hepatokine. In patients with Metabolic Syndrome without the confounding of diabetes or cardiovascular diseases, we showed significant increases in both circulating and subcutaneous adipose tissue secreted Fet-A. Furthermore we showed in mice models increase mRNA and protein following a high fat diet and in a model of metabolic syndrome. This work was recently confirmed by another group of investigators. Hence we propose that Fet-A be considered also as an adipokine.

New Insights Into the Comorbidity of Coronary Heart Disease and Depression

Coronary heart disease (CHD) and depression are common disorders that markedly impair quality of life and impose a great financial burden on society. They are also frequently comorbid, exacerbating patient condition, and worsening prognosis. This comorbidity strongly suggests shared pathologic mechanisms. This review focuses on the incidence of depression in patients with CHD, deleterious effects of depression on CHD symptoms, and the potential mechanisms underlying comorbidity. In addition to the existing frequent mechanisms that are well known for decades, this review summarized interesting and original potential mechanisms to underlie the comorbidity, such as endocrine substances, gut microbiome, and microRNA. Finally, there are several treatment strategies for the comorbidity, involving drugs and psychotherapy, which may provide a theoretical basis for further basic research and clinical investigations on improved therapeutic interventions.

Proposal of a study protocol of a preliminary double-blind randomized controlled trial. Verifying effects of selenium supplementation on selenoprotein p and s genes expression in protein and mRNA levels in subjects with coronary artery disease: selenegene

Background: Selenium is the component of selenocystein amino acid, which itself is the building block of selenoproteins having diverse effects on various aspects of the human health. Among these proteins, selenoprotein P is the central to the distribution and homeostasis of selenium, and selenoprotein S as a transmembrane protein is associated with a range of inflammatory markers, particularly in the context of cardiovascular disease. It is known that selenium status outside of the normal range is considered to confer different benefits or adverse cardiovascular risk factors. Therefore, for the first time, we aimed to verify effects of Selenium supplementation on Selenoprotein P and S Genes Expression in Protein and mRNA Levels in Subjects with Coronary Artery Disease (CAD). Methods: This is the study protocol of a double blinded randomized clinical trial on 130 subjects with angiographically documented stenosis of more than 75% in one or more coronary artery vessels. In this 60-day study, 65 patients in each group received either a 200mg selenium yeast or placebo tablets once daily. During the study, subjects were followed by phone calls and visited our clinic twice to repeat baseline measurements. We hypothesized that our finding would enable a more basic and confirmed understanding for the effect of selenium supplementation by investigating its effect on gene expression levels in people with CAD. Discussion: Upon confirmation of this hypothesis, the beneficial effect of inflammation regulation by supplementation with micronutrients could be considered for subjects with CVD. (www.actabiomedica.it)

Fetuin-A levels are increased in the adipose tissue of diabetic obese humans but not in circulation

Background

The hepatokine fetuin-A is linked to obesity and type 2 diabetes, but its presence and expression in adipose tissue remain unclear. In this study, we aimed to assess the circulating levels of fetuin-A and its expression in subcutaneous adipose tissue (SAT) from diabetic and non-diabetic obese subjects and their modulation by exercise.

Methods

SAT and blood were obtained from adults obese (diabetic, n=118 and non-diabetic, n=166) before and after a 3-month exercise program (diabetic, n=40 and non-diabetic, n=36, respectively). Plasma fetuin-A was assayed using ELISA. The presence and expression of fetuin-A in SAT, peripheral blood mononuclear cells (PBMCs) and cell lines (3T3-L1, THP-1, HepG2, RAW 264.7) were analysed using confocal microscopy, immunoblotting and qRT-PCR.

Results

Plasma fetuin-A level did not significantly differ between diabetic and non-diabetic obese subjects. However, when the non-diabetic group was divided into metabolically healthy and unhealthy phenotypes, significantly higher fetuin-A level was observed in the unhealthy sub-group. Circulating fetuin-A was mainly associated with glycaemic markers. In SAT, fetuin-A protein level was significantly higher in the diabetic obese subjects but its mRNA was not detected. Similarly, fetuin-A protein was detected in PBMCs, but its mRNA was not. In line with this, the use of various cell lines and culture media indicated that the presence of fetuin-A in SAT and PBMCs was due to its uptake from circulation rather than its endogenous expression. Finally, physical exercise decreased fetuin-A levels in both plasma and SAT in both groups.

Conclusions

Fetuin-A levels increased in association with diabetes in SAT but not in circulation in the obese subjects. Moreover, physical exercise decreased fetuin-A level. Fetuin-A potentially acts as a hepatokine taken up by other tissues, such as adipose tissue.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0919-x) contains supplementary material, which is available to authorized users.

Serum levels of fetuin-A are negatively associated with log transformation levels of thyroid-stimulating hormone in patients with hyperthyroidism or euthyroidism: An observational study at a medical center in Taiwan

Fetuin-A is a protein with various biological functions. It plays a role in insulin resistance and arterial calcium deposition. Thyroid dysfunction may affect energy expenditure, glucose metabolism, and the risk of cardiovascular diseases. In the present study, we compared the serum fetuin-A concentrations in hyperthyroid patients with those in euthyroid patients.We recruited 30 newly-diagnosed hyperthyroid patients (the HY group) and treated them with anti-thyroid regimens as clinically indicated. We recruited 30 euthyroid individuals (the EU group) as controls. We compared laboratory parameters at the baseline and at 6 months. We then determined the associations between the levels of fetuin-A and free thyroxine (fT4), thyroid-stimulating hormone (TSH), or log transformation of TSH (logTSH).At the baseline, the HY patients had significantly higher serum fetuin-A levels than the EU patients (median [Q1, Q3]: 735.4 [537.9, 843.4] ng/mL vs 561.1[449.2, 670.5] ng/mL, P = .010). At 6 months, the serum fetuin-A levels of the HY patients decreased but were still higher than those of the EU patients (698.4 [627.6, 924.3] ng/mL vs 616.5 [498.2, 727.7] ng/mL, P = .002). At baseline, the serum levels of fetuin-A were negatively associated with logTSH (β = -53.79, P = .010). At 6 months, the levels of fetuin-A were positively associated with fT4 (β = 86.91, P = .039), and negatively associated with logTSH (β = -104.28, P < .001). Changes to the levels of fetuin-A within 6 months were negatively associated with changes to logTSH (β = -57.80, P = .019). The negative associations between fetuin-A levels and logTSH at baseline and at 6 months, and the changes during the 6 months remained significant after adjustment for sex and age (β = -51.72, P = .016; β = -103.11, P < .001; and β = -59.36, P = .020, respectively).The patients with hyperthyroidism had higher serum fetuin-A levels than the patients with euthyroidism. In patients with hyperthyroidism, the serum fetuin-A concentrations decreased after the anti-thyroid treatment. In the present study, serum fetuin-A concentrations were negatively associated with logTSH.

Non-alcoholic fatty liver disease and hypertension: coprevalent or correlated?

OBJECTIVE

To provide a comprehensive review summarizing the existing evidence on the association between nonalcoholic fatty liver disease (NAFLD) and hypertension (HT) independent of other components of metabolic syndrome.

METHODS

We searched the literature through Medline and the Cochrane Library for studies evaluating the relationship between hypertension and fatty liver disease.

RESULTS

Studies testing this association are limited, but agree that HT and fatty liver disease are inter-related independent of other components of the metabolic syndrome such as obesity and diabetes mellitus. Clinical evidence shows that NAFLD is associated with new-onset HT, whereas increased blood pressure is related to the development of fatty liver disease and the possible subsequent progression to liver fibrosis. Insulin resistance and activation of the renin-angiotensin-aldosterone system (RAAS) might provide potential pathophysiologic links between these clinical entities. Until further evidence is available, patients with HT should be meticulously evaluated and treated for fatty liver disease and vice versa. RAAS inhibitors have been tested in NAFLD, presenting a favorable profile by decreasing insulin resistance and fibrosis progression.

CONCLUSION

NAFLD and HT are associated independent of traditional cardiovascular risk factors. Insulin resistance appears to be the main linking mechanism. Although RAAS inhibitors are the most beneficial treatment option for HT in patients with NAFLD, randomized studies on the administration of these agents in HT patients with NAFDL are warranted to provide optimal treatment options in these high cardiovascular risk individuals.

Clinical and Body Compositional Factors Associated with Metabolic Syndrome in Obese Koreans: A Cross-Sectional Study

BACKGROUND

Obesity and metabolic syndrome (MetS) are increasing rapidly worldwide, but metabolically healthy population exists. Thus, this study evaluated the proportion of obesity and MetS and investigated clinical and body compositional factors associated with MetS in obese Koreans.

METHODS

This cross-sectional observational study enrolled subjects from the Korea National Health and Nutrition Examination Survey (n = 15,408). Obesity was defined by body mass index (BMI) cutoff points of 25 and 27.5 kg/m². Clinical and laboratory parameters were compared by MetS presence and factors associated with insulin resistance or MetS in obese subjects were evaluated by multivariate or logistic regression analyses.

RESULTS

The proportion of obesity was 29.7% at a BMI cutoff point of 25 kg/m² and 10.4% at 27.5 kg/m². The proportion of MetS was greater in obese population and increased with higher obesity cutoff point, where men were more prevalent than women. The subjects with MetS showed higher age, glycated hemoglobin, insulin resistance, liver enzymes, and ferritin compared with metabolically healthy population in both obese genders. Factors associated with insulin level or presence of MetS were high trunk fat percentage, trunk-to-limb fat ratio, and trunk-to-leg fat ratio, but low limb fat percentage and leg fat percentage. Among body composition indices, trunk-to-limb fat ratio and trunk-to-leg fat ratio showed significantly high odds ratios for MetS in both obese genders regardless of BMI cutoff points.

CONCLUSIONS

MetS in obese population concurrently increased with higher obesity cutoff point. Higher age, insulin resistance, liver enzymes, ferritin, and higher proportion of truncal fat mass-to-limb or leg fat mass significantly contribute to MetS, where trunk-to-limb fat ratio and trunk-to-leg fat ratio could be helpful in identifying and preventing MetS in the obese Korean population.

Association of non-alcoholic steatohepatitis with subclinical myocardial dysfunction in non-cirrhotic patients

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) is associated with increased cardiovascular risk. Among categories of NAFLD, hepatic fibrosis is most likely to affect mortality. Myocardial function and its energy metabolism are tightly linked, which might be altered by an insulin resistant condition such as NAFLD. We investigated whether hepatic steatosis and fibrosis were associated with myocardial dysfunction relative to myocardial glucose uptake.

METHODS

A total of 308 patients (190 without NAFLD, 118 with NAFLD) were studied in a tertiary care hospital. Myocardial glucose uptake was evaluated at fasted state using [¹⁸F]-fluorodeoxyglucose-positron emission tomography (¹⁸FDG-PET). Hepatic steatosis and fibrosis were assessed by transient liver elastography (Fibroscan®) with controlled attenuation parameter, which quantifies hepatic fat and by surrogate indices (fatty liver index and NAFLD fibrosis score). Cardiac structure and function were examined by echocardiogram.

RESULTS

Compared to those without NAFLD, patients with NAFLD had alterations in cardiac remodeling, manifested by increased left ventricular mass index, left ventricular end-diastolic diameter, and left atrial volume index (all p <0.05). Hepatic steatosis was significantly associated with left ventricular filling pressure (E/e' ratio), which reflects diastolic dysfunction (p for trend <0.05). Those without NAFLD were more likely to have higher myocardial glucose uptake compared to those with NAFLD. Significant hepatic fibrosis was also correlated with diastolic dysfunction and impaired myocardial glucose uptake. Using multivariable linear regression, E/e' ratio was independently associated with hepatic fibrosis (standardized β = 0.12 to 0.27; all p <0.05). Association between hepatic steatosis and E/e' ratio was also significant (standardized β = 0.10 to 0.15; all p <0.05 excluding the model adjusted for adiposity).

CONCLUSIONS

Hepatic steatosis and fibrosis are significantly associated with diastolic heart dysfunction. This association is linked with myocardial glucose uptake evaluated by ¹⁸FDG-PET.

LAY SUMMARY

Non-alcoholic fatty liver disease is associated with an increased risk of cardiovascular disease. More severe forms of non-alcoholic fatty liver disease, where hepatic fibrosis occurs, are linked to increased mortality. In this study, we have shown that hepatic steatosis and fibrosis are associated with subclinical myocardial dysfunction. This association is linked to altered myocardial glucose uptake.

Implication of liver enzymes on incident cardiovascular diseases and mortality: A nationwide population-based cohort study

Although liver enzymes, such as γ-glutamyltransferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), have recently been suggested as risk factors for cardiovascular diseases (CVD), impact on mortality after myocardial infarction (MI) or ischemic stroke (IS) was not previously examined. Using a population-based, nationwide cohort database, we explored the implication of GGT and aminotransferases on the development of CVD and all-cause mortality during a median 9.1 years of follow-up. Among 16,624,006 Korean adults, both GGT and aminotransferases exhibited a positive relationship with MI, IS, and mortality in a multivariate adjusted model. ALT and AST showed U-shaped associations with mortality, whereas GGT showed a positive linear relationship with mortality. The risk of 1-year mortality after MI or IS was significantly higher in the highest quartile of GGT compared to the lowest quartile (HR, 1.46; 95% CI, 1.40-1.52). The implication of GGT on MI, IS, and mortality persisted regardless of traditional cardiovascular risk parameters. This study demonstrated the unique pattern of association of ALT, AST, and GGT with the development of CVD and all-cause mortality in the Korean population. In particular, GGT showed the most robust linear relationship with mortality before and after cardiovascular events independent of risk factors.

Hypertension, diabetes, atherosclerosis and NASH: Cause or consequence?

Non-alcoholic fatty liver disease (NAFLD) has become one of the most common forms of chronic liver disease worldwide and its prevalence is expected to continue rising. NAFLD has traditionally been considered a consequence of metabolic syndrome (MetS). However, the link between NAFLD and MetS components, especially type 2 diabetes mellitus (T2DM), hypertension (HTN), and cardiovascular disease (CVD) is more complex than previously thought. Indeed, the adverse effects of NAFLD extend far beyond the liver, with a large body of clinical evidence now suggesting that NAFLD may precede and/or promote the development of T2DM, HTN and atherosclerosis/CVD. The risk of developing these cardiometabolic diseases parallels the underlying severity of NAFLD. Accumulating evidence suggests that the presence and severity of NAFLD is associated with an increased risk of incident T2DM and HTN. Moreover, long-term prospective studies indicate that the presence and severity of NAFLD independently predicts fatal and nonfatal CVD events. In this review, we critically discuss the rapidly expanding body of clinical evidence that supports the existence of a bi-directional relationship between NAFLD and various components of MetS, particularly T2DM and HTN, as well as the current knowledge regarding a strong association between NAFLD and CVD morbidity and mortality. Finally, we discuss the most updated putative biological mechanisms through which NAFLD may contribute to the development of HTN, T2DM and CVD.

The persistence of fatty liver has a differential impact on the development of diabetes: The Kangbuk Samsung Health Study

AIMS

To evaluate whether variable fatty liver status over time influence the risk of type 2 diabetes differently.

METHODS

We analyzed the data from 7849 subjects without type 2 diabetes who underwent comprehensive health check-ups annually for 5 years. All subjects had an abdominal ultrasonography annually. The risk of incident diabetes was assessed in individuals with sustained non-alcoholic fatty liver disease (NAFLD), individuals with changed fatty liver status (intermittent NAFLD group), and individuals who did not have NAFLD (never NAFLD group) during the study period. A subgroup analysis was done in subjects of the intermittent NAFLD group. Incident diabetes was compared according to the number of time diagnosed as NAFLD by annual ultrasonography.

RESULTS

During the mean follow-up of 4 years, subjects in the sustained NAFLD group had a HR of 1.50 (95% CI 1.13-1.98) for the development of diabetes compared with those in the never NAFLD group, whereas the risk was not higher in the intermittent NAFLD group (HR 0.99, 95% CI 0.76-1.31). When compared with the intermittent NAFLD group, multivariable adjusted HR for incident diabetes was 1.50 (95% CI 1.20-1.89) in the sustained NAFLD group. As the number of times diagnosed as NAFLD increased, the proportion of subjects who developed diabetes also increased (p = .002).

CONCLUSIONS

The presence of fatty liver was differentially associated with incident diabetes based on its duration. The persistence of fatty liver status is an important factor for an independent association between NAFLD and incident diabetes.

Implication of Nonalcoholic Fatty Liver Disease, Metabolic Syndrome, and Subclinical Inflammation on Mild Renal Insufficiency

BACKGROUND

Limited information exists about the impact of nonalcoholic fatty liver disease (NAFLD) on mild renal insufficiency. We compared the relative influence of NAFLD, metabolic syndrome (MetS), and subclinical inflammation, alone or in combination, on mild renal insufficiency.

METHODS

This study included 1174 Korean adults. NAFLD was diagnosed using ultrasonography. Mild renal insufficiency was defined as an estimated glomerular filtration rate (eGFR) ≥ 60 and <90 mL/min/1.73 m².

RESULTS

In partial correlation analysis, several components of MetS and liver aminotransferase levels, but not high-sensitivity C-reactive protein (hsCRP), were associated with eGFR. Multivariate logistic regression analysis demonstrated the independent association of NAFLD (P = 0.034) and MetS (P = 0.018) with mild renal insufficiency, but not elevated hsCRP (P = 0.885). Furthermore, NAFLD without the MetS group (odds ratio (95% confidence interval) = 1.56 (1.05-2.34)) or MetS without the NAFLD group (1.82 (1.11-3.00)) was associated with mild renal insufficiency after adjusting for confounding variables. However, individuals with high hsCRP showed no relationship with mild renal insufficiency, irrespective of the existence of NAFLD.

CONCLUSIONS

This study demonstrated that NAFLD and MetS are independently associated with mild renal insufficiency, whereas subclinical inflammation did not affect the risk for mild renal insufficiency in Korean adults.

The association between circulating fetuin-A levels and type 2 diabetes mellitus risk: systematic review and meta-analysis of observational studies

BACKGROUND AND OBJECTIVE

Fetuin-A is a liver-derived circulating protein that is associated with insulin resistance and diabetes. The objective of this systematic review and meta-analysis of published observational studies was to investigate mean levels of fetuin-A in T2D patients and the relationship between blood fetuin-A levels and T2D risk.

MATERIALS AND METHODS

PubMed, Embase, Google Scholar, Web of Science, and The Cochrane Library were systematically searched for potential relevant studies up to 1 December 2016. Natural logarithm-transformed estimate risks, standard mean differences on the basis of Hedges's adjusted g, and 95% confidence intervals (CIs) were calculated for all eligible studies and were combined to measure the pooled data using random-effects model.

RESULTS

A total of 32 studies including 27 case-control and 5 cohort studies were included in the current study. Fetuin-A levels in T2D patients were significantly higher than control groups [Hedges' g = 1.73, 95% CI (1.25-2.22), P < 0.001], with significant heterogeneity across studies (P < 0.001, I ² = 98.46%). Findings from meta-analyses of cohort studies showed a statistically significant association between fetuin-A levels and T2D risk [rate ratio = 1.62, 95% CI (1.26-2.08), P < 0.001], with no significant heterogeneity (P = 0.10, I ² = 46.06%).

CONCLUSION

We found a significant relationship between the fetuin-A levels with T2D risk. Although fetuin-A may be as a potential screening and prediction biomarker or a therapeutic target in T2D patients, further studies are required in this regard.

Relationship of Circulating Fetuin-A Levels with Body Size and Metabolic Phenotypes

BACKGROUND

Previous studies have suggested the existence of distinct body size subgroups according to metabolic health referred to as metabolically healthy obesity (MHO) and metabolically abnormal but normal weight (MANW) patients. Although nonalcoholic fatty liver disease (NAFLD) is strongly associated with obesity and metabolic syndrome, the relationship between these phenotypes and fetuin-A, a representative hepatokine, has not been explored.

METHODS

We examined the association between circulating fetuin-A levels, metabolic health phenotypes, cardiometabolic risk parameters, and subclinical atherosclerosis in 290 subjects who were randomly selected from an ongoing cohort study.

RESULTS

Fetuin-A concentrations were significantly associated with detrimental anthropometric and laboratory measurements, including increased waist circumference, blood pressure, alanine aminotransferase, fasting plasma glucose, and triglyceride levels. Furthermore, fetuin-A levels were significantly increased in the metabolically abnormal (MA) group compared to the metabolically healthy (MH) group in subjects without obesity (717.1 [632.1, 769.7] vs. 599.5 [502.0, 709.3], P = 0.001) and subjects with obesity (704.1 [595.5-880.9] vs. 612.2 [547.9-802.1], P = 0.016). In addition, brachial-ankle pulse wave velocity (baPWV), which reflects arterial stiffness, was higher in MA individuals compared to MH individuals. Multiple logistic regression analysis revealed that both individuals without obesity (P for trend = 0.017) and with obesity (P for trend = 0.028) in the higher tertiles of fetuin-A had an increased risk of MA than those in the lowest tertile.

CONCLUSIONS

This study demonstrates that fetuin-A levels are significantly associated with metabolic health phenotypes, such as MHO and MANW, in Korean adults.