TNF-α decreases lipoprotein lipase activity in 3T3-L1 adipocytes by up-regulation of angiopoietin-like protein 4

Association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and Helicobacter pylori infection

Evidence on the association between the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) and Helicobacter pylori (H. pylori) infection remains limited. This study investigates this correlation based on the U.S. population. This cross-sectional research included data on 834 U.S. participants from the National Health and Nutrition Examination Survey 1999-2000. The association between the NHHR and H. pylori infection was examined using logistic regression models, restricted cubic spline (RCS) curve and subgroup analyses. Individuals with H. pylori infection exhibited significantly higher NHHR value. A significant positive association between NHHR and H. pylori infection was observed across all three models, even after adjusting for potential confounders, with a stronger association noted in males, individuals under 60 years of age, and non-Hispanic White participants. These findings suggest NHHR may act as a non-invasive biomarker for detecting H. pylori infection in U.S. populations.

Angiopoietin-like protein 4 dysregulation in kidney diseases: a promising biomarker and therapeutic target

The global burden of renal diseases is increasingly severe, underscoring the need for in-depth exploration of the molecular mechanisms underlying renal disease progression and the development of potential novel biomarkers or therapeutic targets. Angiopoietin-like protein 4 (ANGPTL4) is a multifunctional cytokine involved in the regulation of key biological processes, such as glucose and lipid metabolism, inflammation, vascular permeability, and angiogenesis, all of which play crucial roles in the pathogenesis of kidney diseases. Over the past 2 decades, ANGPTL4 has been regarded as playing a pivotal role in the progression of various kidney diseases, prompting significant interest from the scientific community regarding its potential clinical utility in renal disorders. This review synthesizes the available literature, provides a concise overview of the molecular biological effects of ANGPTL4, and highlights its relationship with multiple renal diseases and recent research advancements. These findings underscore the important gaps that warrant further investigation to develop novel targets for the prediction or treatment of various renal diseases.

The influence of Helicobacter pylori infection on acute coronary syndrome and lipid metabolism in the Chinese ethnicity

Background

Acute coronary syndrome (ACS) patients frequently present a relatively high prevalence of Helicobacter pylori (H. pylori) infection. H. pylori was previously hypothesized to induce ACS through the regulation of lipid levels. However, the risk of H. pylori-induced ACS varies significantly among different ethnic groups, and the associations between H. pylori and lipid parameters remain unclear. This study aimed to systematically assess the risk of ACS in Chinese populations with H. pylori infection while also evaluating the effects of H. pylori on lipid parameters.

Materials and methods

A hospital-based case-control study involving 280 participants was conducted. Immunoblotting was used for the detection and genotyping of H. pylori. The associations between H. pylori and ACS, as well as lipid parameters, were analyzed via the chi-square test and a multiple logistic regression model.

Results

H. pylori infection significantly increased the risk of ACS among all participants (adjusted odds ratio (OR) = 4.04, 95% confidence interval (CI): 1.76-9.25, P < 0.05), with no associations with virulence factors (cytotoxin-associated gene A (CagA) or vacuole toxin geneA (VacA)). Subgroup analysis revealed a significant increase in the risk of ACS among the elderly population aged 56-64 years with H. pylori infection. Additionally, a substantial association was observed between H. pylori and acute myocardial infarction (AMI). No significant differences were found in lipid parameters, including low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and the LDL/HDL ratio, between individuals positive and negative for H. pylori infection. Similar results were observed between the ACS group and the control group.

Conclusions

Our study has demonstrated for the first time that H. pylori does not significantly impact lipid metabolism but increases the risk of ACS fourfold in the Chinese population (OR = 4.04, 95% CI: 1.76-9.25). Furthermore, the virulence factors of H. pylori (CagA and VacA) may not be involved in the mechanisms by which they promote the development of ACS. This finding provides additional evidence for the association between H. pylori and ACS among different ethnic groups and refutes the biological mechanism by which H. pylori affects ACS through lipid metabolism regulation. Regular screening for H. pylori and eradication treatment in elderly individuals and those at high risk for ACS may be effective measures for reducing the incidence of ACS. Future research should include multicenter randomized controlled trials and explore host genetics and the effects of H. pylori on the gut microbiota as potential biological pathways linking H. pylori and ACS.

Causality of anti-Helicobacter pylori IgG levels on myocardial infarction and potential pathogenesis: a Mendelian randomization study

Background

Previous observational studies have shown that a potential relationship between anti-Helicobacter pylori (H. pylori) IgG levels and Myocardial Infarction (MI). Nevertheless, the evidence for the causal inferences remains disputable. To further clarify the relationship between anti-H. pylori IgG levels and MI and explore its pathogenesis, we conducted a Mendelian randomization (MR) analysis.

Methods

In this study, we used two-sample Mendelian Randomization (MR) to assess the causality of anti-H. pylori IgG levels on MI and potential pathogenesis, 12 single nucleotide polymorphisms (SNPs) related to anti-H. pylori IgG levels were obtained from the European Bioinformatics Institute (EBI). Summary data from a large-scale GWAS meta-analysis of MI was utilized as the outcome dataset. Summary data of mediators was obtained from the FinnGen database, the UK Biobank, the EBI database, MRC-IEU database, the International Consortium of Blood Pressure, the Consortium of Within family GWAS. Inverse variance weighted (IVW) analysis under the fixed effect model was identified as our main method. To ensure the reliability of the findings, many sensitivity analyses were performed.

Results

Our study revealed that increases of anti-H. pylori IgG levels were significantly related to an increased risk of MI (OR, 1.104; 95% CI,1.042-1.169; p = 7.084 × 10-4) and decreases in HDL cholesterol levels (β, -0.016; 95% CI, -0.026 to -0.006; p = 2.02 × 10-3). In addition, there was no heterogeneity or pleiotropy in our findings.

Conclusion

This two-sample MR analysis revealed the causality of anti-H. pylori IgG levels on MI, which might be explained by lower HDL cholesterol levels. Further research is needed to clarify the results.

Alcohol, White Adipose Tissue, and Brown Adipose Tissue: Mechanistic Links to Lipogenesis and Lipolysis

According to data from the World Health Organization, there were about 3 million deaths caused by alcohol consumption worldwide in 2016, of which about 50% were related to liver disease. Alcohol consumption interfering with the normal function of adipocytes has an important impact on the pathogenesis of alcoholic liver disease. There has been increasing recognition of the crucial role of adipose tissue in regulating systemic metabolism, far beyond that of an inert energy storage organ in recent years. The endocrine function of adipose tissue is widely recognized, and the significance of the proteins it produces and releases is still being investigated. Alcohol consumption may affect white adipose tissue (WAT) and brown adipose tissue (BAT), which interact with surrounding tissues such as the liver and intestines. This review briefly introduces the basic concept and classification of adipose tissue and summarizes the mechanism of alcohol affecting lipolysis and lipogenesis in WAT and BAT. The adipose tissue-liver axis is crucial in maintaining lipid homeostasis within the body. Therefore, this review also demonstrates the effects of alcohol consumption on the adipose tissue-liver axis to explore the role of alcohol consumption in the crosstalk between adipose tissue and the liver.

Management of Complex Infections in Hemophagocytic Lymphohistiocytosis in Adults

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of excessive immune system activation and inflammatory response due to a variety of primary and secondary factors that can cause a range of clinical symptoms and, in severe cases, life-threatening conditions. Patients with HLH are at increased risk of infection due to their abnormal immune function as well as chemotherapy and immunosuppressive therapy at the time of treatment. At the same time, the lack of specific clinical features makes complex infections in HLH challenging to diagnose and treat. The management of complex infections in HLH requires a multidisciplinary and integrated approach including the early identification of pathogens, the development of anti-infection protocols and regimens, and the elimination of potential infection factors. Especially in HLH patients with septic shock, empirical combination therapy against the most likely pathogens should be initiated, and appropriate anti-infective regimens should be determined based on immune status, site of infection, pathogens, and their drug resistance, with timely antibiotic adjustment by monitoring procalcitonin. In addition, anti-infection prophylaxis for HLH patients is needed to reduce the risk of infection such as prophylactic antibiotics and vaccinations. In conclusion, complex infection in HLH is a serious and challenging disease that requires vigilance, early identification, and timely anti-infective therapy.

Changes in fecal metabolic and lipidomic features by anti-TNF treatment and prediction of clinical remission in patients with ulcerative colitis

Background

Therapeutic targets for ulcerative colitis (UC) and prediction models of antitumor necrosis factor (TNF) therapy outcomes have not been fully reported.

Objective

Investigate the characteristic metabolite and lipid profiles of fecal samples of UC patients before and after adalimumab treatment and develop a prediction model of clinical remission following adalimumab treatment.

Design

Prospective, observational, multicenter study was conducted on moderate-to-severe UC patients (n = 116).

Methods

Fecal samples were collected from UC patients at 8 and 56 weeks of adalimumab treatment and from healthy controls (HC, n = 37). Clinical remission was assessed using the Mayo score. Metabolomic and lipidomic analyses were performed using gas chromatography mass spectrometry and nano electrospray ionization mass spectrometry, respectively. Orthogonal partial least squares discriminant analysis was performed to establish a remission prediction model.

Results

Fecal metabolites in UC patients markedly differed from those in HC at baseline and were changed similarly to those in HC during treatment; however, lipid profiles did not show these patterns. After treatment, the fecal characteristics of remitters (RM) were closer to those of HC than to those of non-remitters (NRM). At 8 and 56 weeks, amino acid levels in RM were lower than those in NRM and similar to those in HC. After 56 weeks, levels of 3-hydroxybutyrate, lysine, and phenethylamine decreased, and dodecanoate level increased in RM similarly to those in HC. The prediction model of long-term remission in male patients based on lipid biomarkers showed a higher performance than clinical markers.

Conclusion

Fecal metabolites in UC patients markedly differ from those in HC, and the levels in RM are changed similarly to those in HC after anti-TNF therapy. Moreover, 3-hydroxybutyrate, lysine, phenethylamine, and dodecanoate are suggested as potential therapeutic targets for UC. A prediction model of long-term remission based on lipid biomarkers may help implement personalized treatment.

Changes in Lipid Metabolism Enzymes in Rat Epididymal Fat after Chronic Central Leptin Infusion Are Related to Alterations in Inflammation and Insulin Signaling

Leptin inhibits food intake and reduces the size of body fat depots, changing adipocyte sensitivity to insulin to restrain lipid accrual. This adipokine may modulate the production of cytokines that could diminish insulin sensitivity, particularly in visceral adipose tissue. To explore this possibility, we examined the effects of chronic central administration of leptin on the expression of key markers of lipid metabolism and its possible relationship with changes in inflammatory- and insulin-signaling pathways in epididymal adipose tissue. Circulating non-esterified fatty acids and pro- and anti-inflammatory cytokines were also measured. Fifteen male rats were divided into control (C), leptin (L, icv, 12 μg/day for 14 days), and pair-fed (PF) groups. We found a decrease in the activity of glucose-6-phosphate dehydrogenase and malic enzyme in the L group, with no changes in the expression of lipogenic enzymes. A reduction in the expression of lipoprotein lipase and carnitine palmitoyl-transferase-1A, together with a decrease in the phosphorylation of insulin-signaling targets and a low-grade inflammatory pattern, were detected in the epididymal fat of L rats. In conclusion, the decrease in insulin sensitivity and increased pro-inflammatory environment could regulate lipid metabolism, reducing epididymal fat stores in response to central leptin infusion.

ANGPTL4, IL-6 and TNF-α as regulators of lipid metabolism during a marathon run

The aim of the study was to reveal whether marathon running influences regulators of lipid metabolism i.e. angiopoietin-like protein 4 (ANGPTL4), interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α). Plasma concentration of ANGPTL4, IL-6, TNF-α and lipids were determined in samples collected from 11 male runners before the marathon, immediately after the run and at 90 min of recovery. Plasma ANGPTL4 increased during exercise from 55.5 ± 13.4 to 78.1 ± 15.0 ng/ml (P < 0.001). This was accompanied by a significant increase in IL-6, TNF-α, free fatty acids (FFA) and glycerol (Gly) and a decrease in triacylglycerols (TG). After 90 min of recovery ANGPTL4 and TG did not differ from the exercise values, while plasma IL-6, TNF-α, FFA and Gly concentration were significantly lower. The exercise-induced increase in plasma concentration of ANGPTL4 correlated positively with the rise in plasma IL-6, TNF-α, FFA and Gly and negatively with the duration of the run. The increase in plasma IL-6 and TNF-α correlated positively with the rise in Gly. Summarizing, marathon running induced an increase in plasma ANGPTL4 and the value was higher in faster runners. The increase in plasma FFA, IL-6 and TNF-α concentration during a marathon run may be involved in plasma ANGPTL4 release, which could be a compensatory mechanism against FFA-induced lipotoxicity and oxidative stress. All of the analyzed cytokines may stimulate lipolysis during exercise.

Relationship between active Helicobacter pylori infection and risk factors of cardiovascular diseases, a cross-sectional hospital-based study in a Sub-Saharan setting

Background

Chronic inflammation has been reported as one of the novel coronary heart disease (CHD) risk factors. Knowing that Helicobacter pylori (H. pylori) provokes a local inflammation, the relationship between H. pylori infection and cardiovascular disease (CVD) has received considerable attention. However, the attempt to demonstrate the association between H. pylori and specific cardiovascular disease risk factors is always a challenging issue due to the conflicting reports in the literatures.

Methods

We performed a cross-sectional study of 363 consecutive dyspeptic subjects in three reference health facilities in Cameroon from October 2020 to October 2021. Each participation gave a written consent and the study was approved by the local Ethical Committee. Check-up for cardiovascular disease (CVD) risk factors such as dyslipidemia-related parameters, obesity-related parameter, high blood pressure as well as H. pylori detection was done for each participant. Data was analyzed using SSPS statistical package.

Results

Helicobacter pylori infection was significantly associated with higher total cholesterol level (OR: 2.3324, p = 0.0002) and higher LDL cholesterol level (OR: 2.3096, p = 0.0006). The crude OR of H. pylori status on the prevalence of high body mass index (BMI) was 1.0813 (p = 0.7300) and the adjusted OR for confounding factors was 1.1785 (p = 0.5095). The strength of the association between H. pylori infection and blood pressure, shows an OR of 1.3807 (p = 0.2991), 1.0060 (p = 0.9855) and 1.4646 (p = 0.2694) for diastolic pressure, hypertension and high heart rate respectively, while that of systolic pressure was 0.8135 (p = 0.4952). H. pylori infection is associated with dyslipidemia in our milieu.

IL-34 was high in serum of women with polycystic ovary syndrome and may function as potential diagnostic biomarker and therapeutic target

BACKGROUND

Polycystic ovary syndrome (PCOS) is one of the most prevalent endocrine disorders in females of reproductive age, with a prevalence of 20%-33% in the general population. Interleukin (IL)-34 is a recently explored proinflammatory cytokine and is an important modulator in different disease types. However, the function of IL-34 in PCOS has yet to be investigated.

OBJECTIVE

The purpose of this study was to determine the IL-34 serum level in women with PCOS and to compare it to that of a relatively healthy control group. Focusing on its relationship with IL-6, TNF-α, and IL-1β and homeostatic model assessment for insulin resistance (HOMA-IR), triglyceride, and low-density lipoprotein cholesterol (LDL-C).

MATERIALS AND METHODS

In this study, blood samples were obtained from 100 women with PCOS and 100 healthy control women for the purpose of estimating their serum levels of IL-34, IL-6, TNF-α, and IL-1β using the enzyme-linked immunosorbent assay technique.

RESULTS

Serum levels of IL-34, IL-6, TNF-α, and IL-1β were all higher in PCOS women than in healthy controls, and the difference was highly statistically significant. Serum IL-34 concentration was positively correlated with IL-6, TNF-α, and IL-1β concentration. Additionally, serum concentrations of IL-34 were positively correlated with HOMA-IR, triglyceride, and LDL-C.

CONCLUSION

When compared to normal women, IL-34, IL-6, TNF-α, and IL-1β levels were highly statistically significant in PCOS, and these high levels were associated with other cytokines (IL-6, TNF-α, and IL-1β), HOMA-IR, triglyceride, and LDL-C.

The lipid paradox in neuroprogressive disorders: Causes and consequences

Chronic systemic inflammation is associated with an increased risk of cardiovascular disease in an environment of low low-density lipoprotein (LDL) and low total cholesterol and with the pathophysiology of neuroprogressive disorders. The causes and consequences of this lipid paradox are explored. Circulating activated neutrophils can release inflammatory molecules such as myeloperoxidase and the pro-inflammatory cytokines interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha. Since activated neutrophils are associated with atherosclerosis and cardiovascular disease and with major depressive disorder, bipolar disorder and schizophrenia, it seems reasonable to hypothesise that the inflammatory molecules released by them may act as mediators of the link between systemic inflammation and the development of atherosclerosis in neuroprogressive disorders. This hypothesis is tested by considering the association at a molecular level of systemic inflammation with increased LDL oxidation; increased small dense LDL levels; increased lipoprotein (a) concentration; secretory phospholipase A₂ activation; cytosolic phospholipase A₂ activation; increased platelet activation; decreased apolipoprotein A1 levels and function; decreased paroxonase-1 activity; hyperhomocysteinaemia; and metabolic endotoxaemia. These molecular mechanisms suggest potential therapeutic targets.

Cardiac Remodeling During Pregnancy With Metabolic Syndrome: Prologue of Pathological Remodeling

BACKGROUND

The heart undergoes physiological hypertrophy during pregnancy in healthy individuals. Metabolic syndrome (MetS) is now prevalent in women of child-bearing age and might add risks of adverse cardiovascular events during pregnancy. The present study asks if cardiac remodeling during pregnancy in obese individuals with MetS is abnormal and whether this predisposes them to a higher risk for cardiovascular disorders.

METHODS

The idea that MetS induces pathological cardiac remodeling during pregnancy was studied in a long-term (15 weeks) Western diet-feeding animal model that recapitulated features of human MetS. Pregnant female mice with Western diet (45% kcal fat)-induced MetS were compared with pregnant and nonpregnant females fed a control diet (10% kcal fat).

RESULTS

Pregnant mice fed a Western diet had increased heart mass and exhibited key features of pathological hypertrophy, including fibrosis and upregulation of fetal genes associated with pathological hypertrophy. Hearts from pregnant animals with WD-induced MetS had a distinct gene expression profile that could underlie their pathological remodeling. Concurrently, pregnant female mice with MetS showed more severe cardiac hypertrophy and exacerbated cardiac dysfunction when challenged with angiotensin II/phenylephrine infusion after delivery.

CONCLUSIONS

These results suggest that preexisting MetS could disrupt physiological hypertrophy during pregnancy to produce pathological cardiac remodeling that could predispose the heart to chronic disorders.

Fasting induces ANGPTL4 and reduces LPL activity in human adipose tissue

Objective

Studies in mice have shown that the decrease in lipoprotein lipase (LPL) activity in adipose tissue upon fasting is mediated by induction of the inhibitor ANGPTL4. Here, we aimed to validate this concept in humans by determining the effect of a prolonged fast on ANGPTL4 and LPL gene and protein expression in human subcutaneous adipose tissue.

Methods

Twenty-three volunteers ate a standardized meal at 18.00 h and fasted until 20.00 h the next day. Blood was drawn and periumbilical adipose tissue biopsies were collected 2 h and 26 h after the meal.

Results

Consistent with previous mouse data, LPL activity in human adipose tissue was significantly decreased by fasting (−60%), concurrent with increased ANGPTL4 mRNA (+90%) and decreased ANGPTL8 mRNA (−94%). ANGPTL4 protein levels in adipose tissue were also significantly increased by fasting (+46%), whereas LPL mRNA and protein levels remained unchanged. In agreement with the adipose tissue data, plasma ANGPTL4 levels increased upon fasting (+100%), whereas plasma ANGPTL8 decreased (−79%). Insulin, levels of which significantly decreased upon fasting, downregulated ANGPTL4 mRNA and protein in primary human adipocytes. By contrast, cortisol, levels of which significantly increased upon fasting, upregulated ANGPTL4 mRNA and protein in primary human adipocytes as did fatty acids.

Conclusion

ANGPTL4 levels in human adipose tissue are increased by fasting, likely via increased plasma cortisol and free fatty acids and decreased plasma insulin, resulting in decreased LPL activity.

This clinical trial was registered with identifier NCT03757767.

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24-h fast in humans reduces LPL activity in subcutaneous adipose tissue.

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24-h fast in humans increases adipose ANGPTL4 mRNA, protein, and plasma ANGPTL4 levels.

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Cortisol, fatty acids, and insulin regulate ANGPTL4 in vitro.

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ANGPTL4 mediates the reduction in adipose LPL activity during fasting.

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24-h fast in humans decreases adipose ANGPTL8 mRNA and plasma ANGPTL8 levels.

Polycystic ovary syndrome associated with increased adiposity interferes with serum levels of TNF-alpha and IL-6 differently from leptin and adiponectin

Objective The aim of this study was to investigate polycystic ovary syndrome (PCOS) and to explore the relationship between body fat percentage and metabolic markers. Subjects and methods Sedentary women were assigned to PCOS (N = 60) and CONTROL (N = 60) groups. Each group was subdivided into three subgroups according to body fat percentage (22-27%, 27-32% and 32-37%). The protocol consisted of assessments of glucose, insulin, androgens, follicle stimulating hormone (FSH), luteinizing hormone (LH), 17-hydroxyprogesterone (17-OHP), leptin, adiponectin, tumor necrosis factor (TNF-α) and interleukin-6 (IL-6). Results The PCOS subgroups showed higher concentrations of androgens, LH and 17-OHP. Leptin showed direct relationship with increased body fat percentage, whereas adiponectin showed the inverse effect. However, both were unaffected by PCOS. TNF-α and IL-6 were higher in PCOS women and showed a direct relationship with increased body fat percentage. Glucose showed direct relationship with body fat percentage, whereas insulin presented higher values in PCOS women and direct relationship with increased body fat percentage. Conclusions Our findings indicate that PCOS and body fat percentage directly influence concentrations of insulin, TNF-α and IL-6, whereas leptin and adiponectin are influenced only by the increase in body fat percentage in these women. Arch Endocrinol Metab. 2020;64(1):4-10.

Triglyceride metabolism and angiopoietin-like proteins in lipoprotein lipase regulation

Hypertriglyceridemia is a risk factor for a series of diseases, such as cardiovascular disease (CVD), diabetes and nonalcoholic fatty liver disease (NAFLD). Angiopoietin-like proteins (ANGPTLs) family, especially ANGPTL3, ANGPTL4 and ANGPTL8, which regulate lipoprotein lipase (LPL) activity, play pivotal roles in triglyceride (TG) metabolism and related diseases/complications. There are many transcriptional and post-transcriptional factors that participate in physiological and pathological regulation of ANGPTLs to affect triglyceride metabolism. This review is intended to focus on the similarity and difference in the expression, structural features, regulation profile of the three ANGPTLs and inhibitory models for LPL. Description of the regulatory factors of ANGPTLs and the properties in regulating the lipid metabolism involved in the underlying mechanisms in pathological effects on diseases will provide potential therapeutic approaches for the treatment of dyslipidemia related diseases.

Epigenetic regulation of lipoprotein lipase gene via BRD4, which is potentially associated with adipocyte differentiation and insulin resistance

Lipoprotein lipase (LPL) is the rate-controlling enzyme for the accumulation of triacylglycerol into adipocytes, which acts by digesting it into glycerol and fatty acids. In this study, we found that treatment with (+)-JQ1, an inhibitor of the bromodomain and extra-terminal (BET) family proteins, for 4 days from the end of stimulation to induce adipocyte differentiation reduced binding of BRD4, a BET family member, within the gene body of Lpl. This eventually downregulated the expression of Lpl in 3T3-L1 adipocytes. Longer treatment for 8 days reduced the acetylation of histones H3 and H4 within the gene body of Lpl and subsequent Lpl expression. Lpl expression in mesenteric adipose tissues was lower in Brd4^+/- heterozygous mice at 14 days after birth than in wild-type mice at the same age. Furthermore, treatment with an inducer of insulin resistance, tumor necrosis factor-α, reduced BRD4 binding and histone acetylation in the gene body of Lpl and its expression. These results indicate that transcriptional elongation of Lpl controlled by BRD4 may be associated with adipocyte differentiation, and that its suppression is potentially associated with insulin resistance of adipocytes.

A review of the multifunctionality of angiopoietin-like 4 in eye disease

Angiopoietin-like protein 4 (ANGPTL4) is a multifunctional cytokine regulating vascular permeability, angiogenesis, and inflammation. Dysregulations in these responses contribute to the pathogenesis of ischemic retinopathies such as diabetic retinopathy (DR), age-related macular degeneration (AMD), retinal vein occlusion, and sickle cell retinopathy (SCR). However, the role of ANGPTL4 in these diseases remains controversial. Here, we summarize the functional mechanisms of ANGPTL4 in several diseases. We highlight original studies that provide detailed data about the mechanisms of action for ANGPTL4, its applications as a diagnostic or prognostic biomarker, and its use as a potential therapeutic target. Taken together, the discussions in this review will help us gain a better understanding of the molecular mechanisms by which ANGPTL4 functions in eye disease and will provide directions for future research.

Serum Angiopoietin-like peptide 4 levels in patients with hepatic steatosis

OBJECTIVES

Angiopoietin-like peptide 4 (ANGPTL-4) plays an important role in lipid metabolism by inhibiting the enzyme lipoprotein lipase. This effect of ANGPTL-4 results in suppression of the release of plasma triglyceride-derived fatty acids. Increase in fatty acid levels entering to the liver and abnormalities in their secretion is one of the main mechanisms in pathogenesis of hepatic steatosis. In this study, we aimed to investigate the role of ANGPTL-4 in pathogenesis of hepatic steatosis by determining its levels in patients with fatty liver disease.

METHODS

Totally 51 patients (age: 37.9 ± 9.9 years, M/F) diagnosed with grade 2-3 hepatic steatosis with ultrasound and 30 healthy volunteers (age: 34.8 ± 9.5 years, M/F) were included in the study. In both groups, routine biochemical tests including fasting blood glucose, fasting insulin levels, triglyceride, total cholesterol, LDL- cholesterol, HDL-cholesterol, AST, ALT, ALP, GGT levels were measured together with the ANGPTL-4 levels. In determination of ANGPTL-4 levels, ELISA was performed.

RESULTS

When compared with the control group, ANGPTL-4 levels were determined to be decreased in patients with hepatic steatosis (369 ± 243 vs 303 ± 286 ng/mL, p = 0.014). There was a negative weak correlation observed between ANGPTL-4 and triglyceride levels (r = -0.246, p = 0.027). Among all groups, when patients with and without insulin resistance were compared; ANGPTL-4 levels were determined to be similar. While fasting blood glucose levels were similar between 2 groups; fasting insulin and triglyceride levels were determined to be increased in hepatic steatosis group (Insulin 17.7 ± 12 vs 7.4 ± 3.3 µIU/mL, p < 0.001, triglyceride 158 ± 46.4 vs 118 ± 59.8 mg/dL p < 0.001).

CONCLUSIONS

We have determined lower serum ANGPTL-4 levels in patients with hepatic steatosis. ANGPTL-4 that is regulating LPL activity plays an important role in fatty liver disease pathogenesis via free fatty acid metabolism and peroxisome proliferator-activated receptor-delta (PPAR-δ). We believe that the results of this study would elucidate the investigations about the mechanism of fatty liver disease development and treatments targeting ANGPTL-4.

Current Helicobacter pylori infection is significantly associated with subclinical coronary atherosclerosis in healthy subjects: A cross-sectional study

Helicobacter pylori is a gastrointestinal pathogen known to be associated with cardiovascular disease (CVD). However, most analyses about the effect of H. pylori infection have been done in patients with a history of CVD but not in healthy subjects. We evaluated the association between H. pylori infection and subclinical atherosclerosis by using cardiac multidetector computed tomography (MDCT) in healthy subjects without previous CVD. From December 2007 to February 2014, 463 subjects who underwent the rapid urease test (CLO test), pulse-wave velocity (PWV) measurement, and MDCT for a self-referred health check-up were enrolled to this study. Helicobacter pylori infection was defined on the basis of CLO test positivity on endoscopic gastric biopsy. Significant coronary artery stenosis was defined as ≥50% stenosis in any of the major epicardial coronary vessel on MDCT. The CLO-positive subjects had a lower high-density lipoprotein-cholesterol (HDL-cholesterol) level compared to the CLO-negative subjects. The incidence of significant coronary stenosis was higher in the CLO-positive group (7.6% vs. 2.9%, P = 0.01). Furthermore, the number of subjects with coronary artery calcium score >0 and log{(number of segments with plaque)+1} were also significantly higher in the CLO-positive group. However, there was no statistical difference in the number of subjects with coronary artery calcium score >100, the prevalence of any plaque nor the plaque characteristics (calcified, mixed, or soft). Pulse-wave velocity (PWV) was neither associated with CLO test positivity. The CLO-positive group was 3-fold more likely to have significant coronary artery stenosis even after adjusting for confounding factors (adjusted odds ratio 2.813, 95% confidence interval 1.051–7.528, P = 0.04). In a healthy population, current H. pylori infection was associated with subclinical but significant coronary artery stenosis. The causal relationship between H. pylori infection and subclinical atherosclerosis in a “healthy” population remains to be investigated in the future.

Calcineurin is an important factor involved in glucose uptake in human adipocytes

Calcineurin inhibitors are used in immunosuppressive therapy applied after transplantation, but they are associated with major metabolic side effects including the development of new onset diabetes. Previously, we have shown that the calcineurin inhibiting drugs tacrolimus and cyclosporin A reduce adipocyte and myocyte glucose uptakes by reducing the amount of glucose transporter type 4 (GLUT4) at the cell surface, due to an increased internalization rate. However, this happens without alteration in total protein and phosphorylation levels of key proteins involved in insulin signalling or in the total amount of GLUT4. The present study evaluates possible pathways involved in the altered internalization of GLUT4 and consequent reduction of glucose uptake provoked by calcineurin inhibitors in human subcutaneous adipose tissue. Short- and long-term treatments with tacrolimus, cyclosporin A or another CNI deltamethrin (herbicide) decreased basal and insulin-dependent glucose uptake in adipocytes, without any additive effects observed when added together. However, no tacrolimus effects were observed on glucose uptake when gene transcription and protein translation were inhibited. Investigation of genes potentially involved in GLUT4 trafficking showed only a small effect on ARHGEF11 gene expression (p < 0.05). In conlusion, the specific inhibition of calcineurin, but not that of protein phosphatases, decreases glucose uptake in human subcutaneous adipocytes, suggesting that calcineurin is an important regulator of glucose transport. This inhibitory effect is mediated via gene transcription or protein translation; however, expression of genes potentially involved in GLUT4 trafficking and endocytosis appears not to be involved in these effects.

Functional Analysis of Promoters from Three Subtypes of the PI3K Family and Their Roles in the Regulation of Lipid Metabolism by Insulin in Yellow Catfish Pelteobagrus fulvidraco

In the present study, the length of 360, 1848 and 367 bp sequences of promoters from three subtypes of PI3K family (PI3KCa, PI3KC2b and PI3KC3) of yellow catfish Pelteobagrus fulvidraco were cloned and characterized. Bioinformatics analysis revealed that PI3KCa, PI3KC2b and PI3KC3 had different structures in their core promoter regions. The promoter regions of PI3KCa and PI3KC2b had CpG islands but no CAAT and TATA box. In contrast, the promoter of PI3KC3 had the canonical TATA and CAAT box but no CpG island. The binding sites of several transcription factors, such as HNF1, STAT and NF-κB, were predicted on PI3KCa promoter. The binding sites of transcription factors, such as FOXO1, PPAR-RXR, STAT, IK1, HNF6 and HNF3, were predicted on PI3KC2b promoter and the binding sites of FOXO1 and STAT transcription factors were predicted on PI3KC3 promoter. Deletion analysis indicated that these transcriptional factors were the potential regulators to mediate the activities of their promoters. Subsequent mutation analysis and electrophoretic mobility-shift assay (EMSA) demonstrated that HNF1 and IK1 directly bound with PI3KCa and PI3KC2b promoters and negatively regulated the activities of PI3KCa and PI3KC2b promoters, respectively. Conversely, FOXO1 directly bound with the PI3KC2b and PI3KC3 promoters and positively regulated their promoter activities. In addition, AS1842856 (AS, a potential FOXO1 inhibitor) incubation significantly reduced the relative luciferase activities of several plasmids of PI3KC2b and PI3KC3 but did not significantly influence the relative luciferase activities of the PI3KCa plasmids. Moreover, by using primary hepatocytes from yellow catfish, AS incubation significantly down-regulated the mRNA levels of PI3KCa, PI3KC2b and PI3KC3 and reduced triacylglyceride (TG) accumulation and insulin-induced TG accumulation, as well as the activities and the mRNA levels of several genes involved in lipid metabolism. Thus, the present study offers new insights into the mechanisms for transcriptional regulation of PI3Ks and for PI3Ks-mediated regulation of lipid metabolism by insulin in fish.