Postprandial activation of leukocyte-endothelium interaction by fatty acids in the visceral adipose tissue microcirculation

Body roundness index improves the predictive value of cardiovascular disease risk in hypertensive patients with obstructive sleep apnea: a cohort study

BACKGROUND

Obesity, especially visceral obesity, plays an important role in the progression of cardiovascular disease (CVD). The body roundness index (BRI) is a new measure of obesity that is considered to reflect visceral obesity more comprehensively than other measures. This study aims to evaluate the relationship between BRI and CVD risk in hypertensive patients with obstructive sleep apnea (OSA) and explore its superiority in predicting CVD.

METHODS

The Cox proportional hazards model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for incident CVD. The area under the curve (AUC), continuous net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were used to assess which measures of obesity had the best predictive value for CVD risk.

RESULTS

During a median follow-up period of 6.8 years, 324 participants suffered a CVD event. After multivariable adjustment, compared with the reference group (the first tertile), the HRs (95% CI) of CVD were 1.25 (95% CI, 0.93-1.70) and 1.74 (95% CI, 1.30-2.33) for subjects in the tertile 2 and tertile 3 groups, respectively. Compared with other measurement indicators, BRI has the highest predictive value for CVD risk [AUC: 0.627, 95% CI: 0.593-0.661]. The addition of the BRI to the fully adjusted multivariate model improved the predictive power for CVD, which was validated in the continuous NRI and the IDI (all P < .05).

CONCLUSIONS

BRI was significantly associated with the risk of CVD in hypertensive patients with OSA. Furthermore, BRI may improve CVD risk prediction in hypertensive patients with OSA.

The evolving functions of the vasculature in regulating adipose tissue biology in health and obesity

Adipose tissue is an endocrine organ and a crucial regulator of energy storage and systemic metabolic homeostasis. Additionally, adipose tissue is a pivotal regulator of cardiovascular health and disease, mediated in part by the endocrine and paracrine secretion of several bioactive products, such as adipokines. Adipose vasculature has an instrumental role in the modulation of adipose tissue expansion, homeostasis and metabolism. The role of the adipose vasculature has been extensively explored in the context of obesity, which is recognized as a global health problem. Obesity-induced accumulation of fat, in combination with vascular rarefaction, promotes adipocyte dysfunction and induces oxidative stress, hypoxia and inflammation. It is now recognized that obesity-associated endothelial dysfunction often precedes the development of cardiovascular diseases. Investigations have revealed heterogeneity within the vascular niche and dynamic reciprocity between vascular and adipose cells, which can become dysregulated in obesity. Here we provide a comprehensive overview of the evolving functions of the vasculature in regulating adipose tissue biology in health and obesity.

Adipocyte Phenotype Flexibility and Lipid Dysregulation

The prevalence of obesity and associated cardiometabolic diseases continues to rise, despite efforts to improve global health. The adipose tissue is now regarded as an endocrine organ since its multitude of secretions, lipids chief among them, regulate systemic functions. The loss of normal adipose tissue phenotypic flexibility, especially related to lipid homeostasis, appears to trigger cardiometabolic pathogenesis. The goal of this manuscript is to review lipid balance maintenance by the lean adipose tissue’s propensity for phenotype switching, obese adipose tissue’s narrower range of phenotype flexibility, and what initial factors account for the waning lipid regulatory capacity. Metabolic, hypoxic, and inflammatory factors contribute to the adipose tissue phenotype being made rigid. A better grasp of normal adipose tissue function provides the necessary context for recognizing the extent of obese adipose tissue dysfunction and gaining insight into how pathogenesis evolves.

Aerobic Exercise Training Improves Microvascular Function and Oxidative Stress Parameters in Diet-Induced Type 2 Diabetic Mice

PURPOSE

Type 2 diabetic (T2D) patients have liver and adipose tissue microcirculation disturbances associated with metabolic dysfunction and disease progression. However, the potential role of aerobic training on hepatic and white adipose tissue (WAT) microcirculation and the underlying mechanisms have not been elucidated to date. Therefore, we investigated the role of aerobic training on liver and WAT microcirculation and AGE-RAGE modulation in T2D mice.

METHODS

The control group (CTL) was fed standard chow, and T2D was induced by feeding male C57BL/6 a high-fat, high-carbohydrate diet for 24 weeks. In the following 12 weeks, mice underwent aerobic training (CTL EX and T2D EX groups), or were kept sedentary (CTL and T2D groups). We assessed metabolic parameters, biochemical markers, oxidative damage, the AGE-RAGE axis, hepatic steatosis, hepatic stellate cells activation (HSC) and liver and WAT microcirculation.

RESULTS

Hepatic microcirculation was improved in T2D EX mice which were associated with improvements in body, liver and fat mass, blood pressure, hepatic steatosis and fibrosis, and decreased HSC and AGE-RAGE activation. In contrast, improvement in WAT microcirculation, that is, decreased leukocyte recruitment and increased perfusion, was associated with increased catalase antioxidant activity.

CONCLUSION

Physical training improves hepatic and adipose tissue microcirculatory dysfunction associated with T2D, likely due to downregulation of AGE-RAGE axis, decreased HSC activation and increased antioxidant activity.

Insulin Sensitivity Is Retained in Mice with Endothelial Loss of Carcinoembryonic Antigen Cell Adhesion Molecule 1

CEACAM1 regulates endothelial barrier integrity. Because insulin signaling in extrahepatic target tissues is regulated by insulin transport through the endothelium, we aimed at investigating the metabolic role of endothelial CEACAM1. To this end, we generated endothelial cell-specific Ceacam1 null mice (VECadCre+Cc1^fl/fl) and carried out their metabolic phenotyping and mechanistic analysis by comparison to littermate controls. Hyperinsulinemic-euglycemic clamp analysis showed intact insulin sensitivity in VECadCre+Cc1^fl/fl mice. This was associated with the absence of visceral obesity and lipolysis and normal levels of circulating non-esterified fatty acids, leptin, and adiponectin. Whereas the loss of endothelial Ceacam1 did not affect insulin-stimulated receptor phosphorylation, it reduced IRS-1/Akt/eNOS activation to lower nitric oxide production resulting from limited SHP2 sequestration. It also reduced Shc sequestration to activate NF-κB and increase the transcription of matrix metalloproteases, ultimately inducing plasma IL-6 and TNFα levels. Loss of endothelial Ceacam1 also induced the expression of the anti-inflammatory CEACAM1-4L variant in M2 macrophages in white adipose tissue. Together, this could cause endothelial barrier dysfunction and facilitate insulin transport, sustaining normal glucose homeostasis and retaining fat accumulation in adipocytes. The data assign a significant role for endothelial cell CEACAM1 in maintaining insulin sensitivity in peripheral extrahepatic target tissues.

Glucose-dependent insulinotropic polypeptide modifies adipose plasticity and promotes beige adipogenesis of human omental adipose-derived stem cells

The adipocyte precursors (APs) located in white adipose tissue (WAT) are functionally significant in adipose plasticity and browning. Modifying adipogenesis or WAT browning targeted on APs is a promising mechanism for anti-obesity drug. We herein explored the in vitro actions and mechanisms of glucose-dependent insulinotropic polypeptide (GIP), a gut-derived peptide, in human adipose-derived mesenchymal stem cells (hADSCs) isolated from omentum. The hADSCs were cotreated with 100 nM GIP with or without equimolar concentration of GIP3-42 (a GIP receptor antagonist), and subsequently examined in vitro. CCK-8, EdU incorporation, and flow cytometry assays were used to assess cellular proliferation. Annexin V FTIC/PI double stain, TUNEL staining, and Western blot were applied for apoptosis evaluation. Adipogenesis was reflected by Western blot, real-time PCR, Oil Red O staining, mitochondrial staining, and mitochondrial DNA analysis. Results showed that GIP promoted proliferation and inhibited apoptosis of hADSCs via pleiotropic effects. Besides, GIP facilitated de novo beige adipogenesis, by accelerating mitotic clonal expansion (MCE), upregulating core adipogenic regulators (C/EBPα and PPARγ), augmenting beige-related genes (UCP1, PGC1α, and PRDM16), increasing mitochondrial content and improving beige adipocyte functionalities. Above all, our study expands knowledge on the mechanisms of GIP modifying adipogenesis especially in inducing beige adipogenesis, and thus provides a theoretical support for clinical usage of GIP on obesity treatment.

Trained Immunity and Reactivity of Macrophages and Endothelial Cells

Innate immune cells can develop exacerbated immunologic response and long-term inflammatory phenotype following brief exposure to endogenous or exogenous insults, which leads to an altered response towards a second challenge after the return to a nonactivated state. This phenomenon is known as trained immunity (TI). TI is not only important for host defense and vaccine response but also for chronic inflammations such as cardiovascular and metabolic diseases such as atherosclerosis. TI can occur in innate immune cells such as monocytes/macrophages, natural killer cells, endothelial cells (ECs), and nonimmune cells, such as fibroblast. In this brief review, we analyze the significance of TI in ECs, which are also considered as innate immune cells in addition to macrophages. TI can be induced by a variety of stimuli, including lipopolysaccharides, BCG (bacillus Calmette-Guerin), and oxLDL (oxidized low-density lipoprotein), which are defined as risk factors for cardiovascular and metabolic diseases. Furthermore, TI in ECs is functional for inflammation effectiveness and transition to chronic inflammation. Rewiring of cellular metabolism of the trained cells takes place during induction of TI, including increased glycolysis, glutaminolysis, increased accumulation of tricarboxylic acid cycle metabolites and acetyl-coenzyme A production, as well as increased mevalonate synthesis. Subsequently, this leads to epigenetic remodeling, resulting in important changes in chromatin architecture that enables increased gene transcription and enhanced proinflammatory immune response. However, TI pathways and inflammatory pathways are separated to ensure memory stays when inflammation undergoes resolution. Additionally, reactive oxygen species play context-dependent roles in TI. Therefore, TI plays significant roles in EC and macrophage pathology and chronic inflammation. However, further characterization of TI in ECs and macrophages would provide novel insights into cardiovascular disease pathogenesis and new therapeutic targets. Graphic Abstract: A graphic abstract is available for this article.

Vascular Endothelial Cells and Innate Immunity

In addition to the roles of endothelial cells (ECs) in physiological processes, ECs actively participate in both innate and adaptive immune responses. We previously reported that, in comparison to macrophages, a prototypic innate immune cell type, ECs have many innate immune functions that macrophages carry out, including cytokine secretion, phagocytic function, antigen presentation, pathogen-associated molecular patterns-, and danger-associated molecular patterns-sensing, proinflammatory, immune-enhancing, anti-inflammatory, immunosuppression, migration, heterogeneity, and plasticity. In this highlight, we introduce recent advances published in both ATVB and many other journals: (1) several significant characters classify ECs as novel immune cells not only in infections and allograft transplantation but also in metabolic diseases; (2) several new receptor systems including conditional danger-associated molecular pattern receptors, nonpattern receptors, and homeostasis associated molecular patterns receptors contribute to innate immune functions of ECs; (3) immunometabolism and innate immune memory determine the innate immune functions of ECs; (4) a great induction of the immune checkpoint receptors in ECs during inflammations suggests the immune tolerogenic functions of ECs; and (5) association of immune checkpoint inhibitors with cardiovascular adverse events and cardio-oncology indicates the potential contributions of ECs as innate immune cells.