Role of perivascular adipose tissue on vascular reactive oxygen species in type 2 diabetes: a give-and-take relationship

Molecular mechanisms and potential therapeutic targets in the pathogenesis of hypertension in visceral adipose tissue induced by a high-fat diet

Background

Hypertension (HTN) presents a significant global public health challenge with diverse causative factors. The accumulation of visceral adipose tissue (VAT) due to a high-fat diet (HFD) is an independent risk factor for HTN. While various studies have explored pathogenic mechanisms, a comprehensive understanding of impact of VAT on blood pressure necessitates bioinformatics analysis.

Methods

Datasets GSE214618 and GSE188336 were acquired from the Gene Expression Omnibus and analyzed to identify shared differentially expressed genes between HFD-VAT and HTN-VAT. Gene Ontology enrichment and protein-protein interaction analyses were conducted, leading to the identification of hub genes. We performed molecular validation of hub genes using RT-qPCR, Western-blotting and immunofluorescence staining. Furthermore, immune infiltration analysis using CIBERSORTx was performed.

Results

This study indicated that the predominant characteristic of VAT in HTN was related to energy metabolism. The red functional module was enriched in pathways associated with mitochondrial oxidative respiration and ATP metabolism processes. Spp1, Postn, and Gpnmb in VAT were identified as hub genes on the pathogenic mechanism of HTN. Proteins encoded by these hub genes were closely associated with the target organs-specifically, the resistance artery, aorta, and heart tissue. After treatment with empagliflozin, there was a tendency for Spp1, Postn, and Gpnmb to decrease in VAT. Immune infiltration analysis confirmed that inflammation and immune response may not be the main mechanisms by which visceral adiposity contributes to HTN.

Conclusions

Our study pinpointed the crucial causative factor of HTN in VAT following HFD. Spp1, Postn, and Gpnmb in VAT acted as hub genes that promote elevated blood pressure and can be targets for HTN treatment. These findings contributed to therapeutic strategies and prognostic markers for HTN.

Expression of ICAM-1 and E-selectin in different metabolic obesity phenotypes: discrepancy for endothelial dysfunction

OBJECTIVES

Endothelial dysfunction, the earliest vascular alteration, is a consequence of metabolic disorders associated with obesity. However, it is still unclear whether a proportion of obese individuals without metabolic alterations associated with obesity, defined as "metabolically healthy obesity (MHO)", exhibit better endothelial function. We therefore aimed to investigate the association of different metabolic obesity phenotypes with endothelial dysfunction.

METHODS

The obese participants without clinical cardiovascular disease from the MESA (Multi-Ethnic Study of Atherosclerosis) were allocated to the different metabolic obesity phenotypes based on their metabolic status, including MHO and metabolically unhealthy obesity (MUO). Associations of metabolic obesity phenotypes with the biomarkers of endothelial dysfunction, including soluble intercellular adhesion molecule-1 (sICAM-1) and soluble E-selectin (sE-selectin), were evaluated using multiple linear regression models.

RESULTS

Plasma levels of sICAM-1 and sE-selectin were respectively measured in 2371 and 968 participants. Compared to the non-obese participants, those with MUO were associated with higher concentrations of sICAM-1 (β 22.04, 95% CI 14.33-29.75, P < 0.001) and sE-selectin (β 9.87, 95% CI 6.00-13.75, P < 0.001) after adjusting for confounders. However, no differences were found for the concentrations of sICAM-1 (β 0.70, 95% CI - 8.91 to 10.32, P = 0.886) and sE-selectin (β 3.69, 95% CI - 1.13 to 8.51, P = 0.133) in the participants with MHO compared to the non-obese participants.

CONCLUSIONS

Individuals with MUO were associated with elevated biomarkers of endothelial dysfunction, but the association with endothelial dysfunction was not found in those with MHO, indicating that the individuals with MHO might exhibit better endothelial function.

Adipose tissue‑derived extracellular vesicles: Systemic messengers in health and disease (Review)

Adipose tissue (AT) is a complicated metabolic organ consisting of a heterogeneous population of cells that exert wide‑ranging effects on the regulation of systemic metabolism and in maintaining metabolic homeostasis. Various obesity‑related complications are associated with the development of dysfunctional AT. As an essential transmitter of intercellular information, extracellular vesicles (EVs) have recently been recognized as crucial in regulating multiple physiological functions. AT‑derived extracellular vesicles (ADEVs) have been shown to facilitate cellular communication both inside and between ATs and other peripheral organs. Here, the role of EVs released from ATs in the homeostasis of metabolic and cardiovascular diseases, cancer, and neurological disorders by delivering lipids, proteins, and nucleic acids between different cells is summarized. Furthermore, the differences in the sources of ADEVs, such as adipocytes, AT macrophages, AT‑derived stem cells, and AT‑derived mesenchymal stem cells, are also discussed. This review may provide valuable information for the potential application of ADEVs in metabolic syndrome, cardiovascular diseases, cancer, and neurological disorders.

Importance of cardiac imaging assessment of epicardial adipose tissue after a first episode of myocardial infarction

BACKGROUND

Over the past years, information about the crosstalk between the epicardial adipose tissue (EAT) and the cardiovascular system has emerged. Notably, in the context of acute myocardial infarction (AMI), EAT might have a potential role in the pathophysiology of ventricular structural changes and function, and the clinical evolution of patients. This study aims to assess the impact of EAT on morpho-functional changes in the left ventricle (LV) and the outcome of patients after an AMI.

METHODS

We studied prospectively admitted patients to our hospital with a first episode of AMI. All patients underwent percutaneous coronary intervention (PCI) during admission. Transthoracic echocardiography (TTE) was performed within 24-48 h after PCI, as well as blood samples to assess levels of galectin-3 (Gal-3). Cardiac magnetic resonance (CMR) was performed 5-7 days after PCI. Clinical follow-up was performed at 1 and 5 years after MI.

RESULTS

Mean age of our cohort (n = 41) was 57.5 ± 10 years, and 38 (93%) were male. Nine patients had normal BMI, 15 had overweight (BMI 25-30), and 17 were obese (BMI > 30). Twenty three patients (56%) had ≥ 4 mm thickness of EAT measured with echo. In these patients, baseline left ventricular ejection fraction (LVEF) after AMI was significantly lower, as well as global longitudinal strain. EAT thickness ≥ 4 m patients presented larger infarct size, higher extracellular volume, and higher T1 times than patients with EAT < 4 mm. As for Gal-3, the median was 16.5 ng/mL [12.7-25.2]. At five-year follow-up 5 patients had major cardiac events, and all of them had EAT ≥ 4 mm.

CONCLUSIONS

Patients with EAT >4 mm have worse LVEF and GLS, larger infarct size and longer T1 values after a MI, and higher levels of Gal-3. EAT >4 mm was an independent predictor of MACE at 5-year follow-up. EAT thickness is a feasible, noninvasive, low-cost parameter that might provide important information regarding the chronic inflammatory process in the myocardium after an infarction.

Urine Di-(2-ethylhexyl) Phthalate Metabolites Are Independently Related to Body Fluid Status in Adults: Results from a U.S. Nationally Representative Survey

Purpose: Di-(2-ethylhexyl) phthalate (DEHP) has been utilized in many daily products for decades. Previous studies have reported that DEHP exposure could induce renin–angiotensin–aldosterone system activation and increase epithelial sodium channel (ENaC) activity, which contributes to extracellular fluid (ECF) volume expansion. However, there is also no previous study to evaluate the association between DEHP exposure and body fluid status. Methods: We selected 1678 subjects (aged ≥18 years) from a National Health and Nutrition Examination Survey (NHANES) in 2003–2004 to determine the relationship between urine DEHP metabolites and body composition (body measures, bioelectrical impedance analysis (BIA)). Results: After weighing the sampling strategy in multiple linear regression analysis, we report that higher levels of DEHP metabolites are correlated with increases in body measures (body weight, body mass index (BMI), waist circumference), BIA parameters (estimated fat mass, percent body fat, ECF, and ECF/intracellular fluid (ICF) ratio) in multiple linear regression analysis. The relationship between DEHP metabolites and the ECF/ICF ratio was more evident in subjects of younger age (20–39 years old), women, non-Hispanic white ethnicity, and subjects who were not active smokers. Conclusion: In addition to being positively correlated with body measures and body fat, we found that urine DEHP metabolites were positively correlated with ECF and the ECF/ICF ratio in the US general adult population. The finding implies that DEHP exposures might increase ECF volume and the ECF/ICF ratio, which may have adverse health outcomes on the cardiovascular system. Further research is needed to clarify the causal relationship.

Urban fine particulate air pollution exposure promotes atherosclerosis in apolipoprotein E-deficient mice by activating perivascular adipose tissue inflammation via the Wnt5a/Ror2 signaling pathway

Urban fine particulate matter (PM_2.5) is a deleterious risk factor in the ambient air and is recognized to exacerbate atherosclerosis. Perivascular adipose tissue (PVAT) secretes a large number of inflammatory cytokines and plays a crucial role in the pathogenic microenvironment of atherogenesis. However, there is a lack of knowledge about the role of PVAT inflammation in the genesis of PM_2.5-related atherosclerosis. The aim of this research was to probe the latent links between PM_2.5 exposure and PVAT inflammation and further discovered the underlying mechanisms of PM_2.5-triggered atherosclerosis pathogenesis. Apolipoprotein E-deficient (ApoE^-/-) mice were exposed to real-world atmospheric PM_2.5 or filtered clean air for three months, the Wnt5a inhibitor Box5 and the Ror2 inhibitor β-Arrestin2 were applied to verify the possible mechanisms. We noticed that the average daily PM_2.5 mass concentration was 84.27 ± 28.84 μg/m³. PM_2.5 inhalation might significantly expedite the deterioration of atherosclerosis, increase the protein and mRNA expressions of MCP-1, IL-6, TNF-α, Wnt5a, and Ror2 in PVAT tissues, upregulate the distributions of IL-6, TNF-α, MCP-1, and leptin in the histological sections of PVAT, promote lipid deposition in the aorta, elevate the plasma levels of leptin, MCP-1, IL-6, TNF-α, LDL-C, TC, and TG, however, decrease the plasma levels of adiponectin and HDL-C, downregulate the distribution of adiponectin. Nevertheless, these effects caused by PM_2.5 exposure were dramatically diminished after the administration of Box5 or β-Arrestin2. This research illuminated that PVAT inflammation was involved in the PM_2.5-induced atherosclerosis process, as well as lipid deposition, which was closely associated with the activation of the Wnt5a/Ror2 signaling pathway.

Beta vulgaris rubra L. (Beetroot) Peel Methanol Extract Reduces Oxidative Stress and Stimulates Cell Proliferation via Increasing VEGF Expression in H2O2 Induced Oxidative Stressed Human Umbilical Vein Endothelial Cells

The antioxidant capacity of polyphenols and flavonoids present in dietary agents aids in arresting the development of reactive oxygen species (ROS) and protecting endothelial smooth muscle cells from oxidative stress/induced necrosis. Beetroot (Beta vulgaris var. rubra L.; BVr) is a commonly consumed vegetable representing a rich source of antioxidants. Beetroot peel’s bioactive compounds and their role in human umbilical vein endothelial cells (HUVECs) are still under-researched. In the present study, beetroot peel methanol extract (BPME) was prepared, and its effect on the bio-efficacy, nuclear integrity, mitochondrial membrane potential and vascular cell growth, and immunoregulation-related gene expression levels in HUVECs with induced oxidative stress were analysed. Gas chromatography–mass spectroscopy (GC-MS) results confirmed that BPME contains 5-hydroxymethylfurfural (32.6%), methyl pyruvate (15.13%), furfural (9.98%), and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-Pyran-4-one (12.4%). BPME extract effectively enhanced cell proliferation and was confirmed by MTT assay; the nuclear integrity was confirmed by propidium iodide (PI) staining assay; the mitochondrial membrane potential (Δψ_m) was confirmed by JC-1 staining assay. Annexin V assay confirmed that BPME-treated HUVECs showed 99% viable cells, but only 39.8% viability was shown in HUVECs treated with H₂O₂ alone. In addition, BPME treatment of HUVECs for 48 h reduced mRNA expression of lipid peroxide (LPO) and increased NOS-3, Nrf-2, GSK-3β, GPX, endothelial nitric oxide synthase (eNOS) and vascular cell growth factor (VEGF) mRNA expression levels. We found that BPME treatment decreased proinflammatory (nuclear factor-κβ (F-κβ), tissue necrosis factor-α (TNF-α), toll-like receptor-4 (TLR-4), interleukin-1β (IL-1β)) and vascular inflammation (intracellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), EDN₁, IL-1β)-related mRNA expressions. In conclusion, beetroot peel treatment effectively increased vascular smooth cell growth factors and microtubule development, whereas it decreased vascular inflammatory regulators. BPME may be beneficial for vascular smooth cell regeneration, tissue repair and anti-ageing potential.

The Association of Body Composition Parameters and Simultaneously Measured Inter-Arm Systolic Blood Pressure Differences

Background and Objectives: An inter-arm systolic blood pressure difference (IASBPD) is defined as a blood pressure (BP) disparity of ≥10 mmHg between arms. IASBPDs are associated with an increased risk of cardiovascular disease (CVD). Similarly, visceral fat accumulation (VFA) is clinically important because it is associated with higher cardiovascular disease risk. Accordingly, this study compared the body composition parameters of IASBPD individuals with individuals who did not express an IASBPD. Materials and Methods: The analysis included 104 patients. The blood pressures of all participants were measured simultaneously in both arms using automated oscillometric devices. Then patients were divided into two groups according to their IASBPD status: Group 1 (IASBPD- (<10 mmHg)); Group 2 (IASPPD+ (≥10 mmHg)). Body composition parameters were measured using bioelectrical impedance analysis. Results: In 42 (40%) patients, the simultaneously measured IASBPD was equal to or higher than 10 mmHg. The right brachial SBP was higher in 63% of patients. There were no differences between the groups in terms of demographic and clinical characteristics. Regarding the two groups' body composition parameter differences, VFA was significantly higher in group 2 (p = 0.014). Conclusions: The IASBPD is known to be associated with an increased risk of cardiovascular events. Although the body mass indexes (BMIs) of the two groups were similar, VFA levels in those with a greater than 10 mmHg IASBPD were found to be significantly higher. This finding may explain the increased cardiovascular risk in this group.

Obesity, Adipose Tissue and Vascular Dysfunction

Cardiovascular diseases are the leading cause of death worldwide. Overweight and obesity are strongly associated with comorbidities such as hypertension and insulin resistance, which collectively contribute to the development of cardiovascular diseases and resultant morbidity and mortality. Forty-two percent of adults in the United States are obese, and a total of 1.9 billion adults worldwide are overweight or obese. These alarming numbers, which continue to climb, represent a major health and economic burden. Adipose tissue is a highly dynamic organ that can be classified based on the cellular composition of different depots and their distinct anatomical localization. Massive expansion and remodeling of adipose tissue during obesity differentially affects specific adipose tissue depots and significantly contributes to vascular dysfunction and cardiovascular diseases. Visceral adipose tissue accumulation results in increased immune cell infiltration and secretion of vasoconstrictor mediators, whereas expansion of subcutaneous adipose tissue is less harmful. Therefore, fat distribution more than overall body weight is a key determinant of the risk for cardiovascular diseases. Thermogenic brown and beige adipose tissue, in contrast to white adipose tissue, is associated with beneficial effects on the vasculature. The relationship between the type of adipose tissue and its influence on vascular function becomes particularly evident in the context of the heterogenous phenotype of perivascular adipose tissue that is strongly location dependent. In this review, we address the abnormal remodeling of specific adipose tissue depots during obesity and how this critically contributes to the development of hypertension, endothelial dysfunction, and vascular stiffness. We also discuss the local and systemic roles of adipose tissue derived secreted factors and increased systemic inflammation during obesity and highlight their detrimental impact on cardiovascular health.

Inflammation, Nitro-Oxidative Stress, Impaired Autophagy, and Insulin Resistance as a Mechanistic Convergence Between Arterial Stiffness and Alzheimer's Disease

The average age of the world's elderly population is steadily increasing. This unprecedented rise in the aged world population will increase the prevalence of age-related disorders such as cardiovascular disease (CVD) and neurodegeneration. In recent years, there has been an increased interest in the potential interplay between CVDs and neurodegenerative syndromes, as several vascular risk factors have been associated with Alzheimer's disease (AD). Along these lines, arterial stiffness is an independent risk factor for both CVD and AD. In this review, we discuss several inflammaging-related disease mechanisms including acute tissue-specific inflammation, nitro-oxidative stress, impaired autophagy, and insulin resistance which may contribute to the proposed synergism between arterial stiffness and AD.

Vascular Oxidative Stress: Impact and Therapeutic Approaches

Oxidative stress has been defined as an imbalance between oxidants and antioxidants and more recently as a disruption of redox signaling and control. It is generally accepted that oxidative stress can lead to cell and tissue injury having a fundamental role in vascular dysfunction. Physiologically, reactive oxygen species (ROS) control vascular function by modulating various redox-sensitive signaling pathways. In vascular disorders, oxidative stress instigates endothelial dysfunction and inflammation, affecting several cells in the vascular wall. Vascular ROS are derived from multiple sources herein discussed, which are prime targets for therapeutic development. This review focuses on oxidative stress in vascular physiopathology and highlights different strategies to inhibit ROS production.

Vascular dysfunction elicited by a cross talk between periaortic adipose tissue and the vascular wall is reversed by pioglitazone

AIM

Perivascular adipose tissue (PVAT) is in intimate contact with the vessel wall and extravascular PVAT-derived inflammatory mediators may adversely influence atherosclerotic plaque formation and stability through outside-to-inside signaling. We sought to investigate the role of PVAT on the atheroma development in an experimental animal model of metabolic syndrome (MS) associated with oxidative stress and low-grade inflammatory state. We also studied the effect of pioglitazone an insulin sensitizer, on the aortic wall and its surrounding PVAT, considering a bi-directional communication between both layers.

METHODS

Apolipoprotein E-deficient mice (ApoE^-/- ) were fed with standard diet (CD, control diet) or fructose overload (10% w/v) (FD, fructose diet) for 8 weeks and treated with or without pioglitazone the latest 4 weeks.

RESULTS

Biochemical variables show that glycemia and lipid peroxidation determined by thiobarbituric acid reactive species (TBARS) significantly increased in FD-fed ApoE^-/- mice. FD significantly increased aortic PVAT expression of oxidative stress associated genes: p22^phox , Nox1, Nox2, Nox4 and p47^phox , and proinflammatory genes: Visfatin, MCP-1, and MMP-9. Pioglitazone diminished PVAT-oxidative damage elicited by fructose treatment and markedly down-regulated proinflammatory markers. Even pioglitazone did not prevent the development of the aortic atheroma plaques stimulated by FD, significantly diminished VCAM-1 expression, MMP-9 expression and activity in aortic media wall and significantly reduced the accumulation of lipids and macrophages in atheroma plaques.

CONCLUSION

Our results support the fact that PVAT contributes to the development and progression of cardiovascular disease by underlying mechanisms elicited by "outside-in" signaling. Treatment with pioglitazone may offer a new effect on the whole vessel wall, promoting the stability of advanced atherosclerotic plaques.

Fast assessment of lipid content in arteries in vivo by intravascular photoacoustic tomography

Intravascular photoacoustic tomography is an emerging technology for mapping lipid deposition within an arterial wall for the investigation of the vulnerability of atherosclerotic plaques to rupture. By converting localized laser absorption in lipid-rich biological tissue into ultrasonic waves through thermoelastic expansion, intravascular photoacoustic tomography is uniquely capable of imaging the entire arterial wall with chemical selectivity and depth resolution. However, technical challenges, including an imaging catheter with sufficient sensitivity and depth and a functional sheath material without significant signal attenuation and artifact generation for both photoacoustics and ultrasound, have prevented in vivo application of intravascular photoacoustic imaging for clinical translation. Here, we present a highly sensitive quasi-collinear dual-mode photoacoustic/ultrasound catheter with elaborately selected sheath material, and demonstrated the performance of our intravascular photoacoustic tomography system by in vivo imaging of lipid distribution in rabbit aortas under clinically relevant conditions at imaging speeds up to 16 frames per second. Ex vivo evaluation of fresh human coronary arteries further confirmed the performance of our imaging system for accurate lipid localization and quantification of the entire arterial wall, indicating its clinical significance and translational capability.

Cellular mechanisms underlying obesity-induced arterial stiffness

Obesity is an emerging pandemic driven by consumption of a diet rich in fat and highly refined carbohydrates (a Western diet) and a sedentary lifestyle in both children and adults. There is mounting evidence that arterial stiffness in obesity is an independent and strong predictor of cardiovascular disease (CVD), cognitive functional decline, and chronic kidney disease. Cardiovascular stiffness is a precursor to atherosclerosis, systolic hypertension, cardiac diastolic dysfunction, and impairment of coronary and cerebral flow. Moreover, premenopausal women lose the CVD protection normally afforded to them in the setting of obesity, insulin resistance, and diabetes, and this loss of CVD protection is inextricably linked to an increased propensity for arterial stiffness. Stiffness of endothelial and vascular smooth muscle cells, extracellular matrix remodeling, perivascular adipose tissue inflammation, and immune cell dysfunction contribute to the development of arterial stiffness in obesity. Enhanced endothelial cortical stiffness decreases endothelial generation of nitric oxide, and increased oxidative stress promotes destruction of nitric oxide. Our research over the past 5 years has underscored an important role of increased aldosterone and vascular mineralocorticoid receptor activation in driving development of cardiovascular stiffness, especially in females consuming a Western diet. In this review the cellular mechanisms of obesity-associated arterial stiffness are highlighted.

The Renin Angiotensin Aldosterone System in Obesity and Hypertension: Roles in the Cardiorenal Metabolic Syndrome

In the United States, more than 50 million people have blood pressure at or above 120/80 mm Hg. All components of cardiorenal metabolic syndrome (CRS) are linked to metabolic abnormalities and obesity. A major driver for CRS is obesity. Current estimates show that many of those with hypertension and CRS show some degree of systemic and cardiovascular insulin resistance. Several pathophysiologic factors participate in the link between hypertension and CRS. This article updates recent literature with a focus on the function of insulin resistance, obesity, and renin angiotensin aldosterone system-mediated oxidative stress on endothelial dysfunction and the pathogenesis of hypertension.

Vascular stiffness in insulin resistance and obesity

Obesity, insulin resistance, and type 2 diabetes are associated with a substantially increased prevalence of vascular fibrosis and stiffness, with attendant increased risk of cardiovascular and chronic kidney disease. Although the underlying mechanisms and mediators of vascular stiffness are not well understood, accumulating evidence supports the role of metabolic and immune dysregulation related to increased adiposity, activation of the renin angiotensin aldosterone system, reduced bioavailable nitric oxide, increased vascular extracellular matrix (ECM) and ECM remodeling in the pathogenesis of vascular stiffness. This review will give a brief overview of the relationship between obesity, insulin resistance and increased vascular stiffness to provide a contemporary understanding of the proposed underlying mechanisms and potential therapeutic strategies.