Obesity Induces Artery-Specific Alterations: Evaluation of Vascular Function and Inflammatory and Smooth Muscle Phenotypic Markers

Association Between Cardiovascular Health and Retinopathy in US Adults: From NHANES 2005-2008

PURPOSE

Investigating the relationship between cardiovascular health (CVH) and retinopathy in the adult population of the United States.

DESIGN

The cross-sectional study.

METHODS

The study utilized samples, including the diabetes population, from the National Health and Nutrition Examination Survey (NHANES) conducted between 2005 and 2008 (N= 4249), to assess cardiovascular health (CVH) using the Life's Essential 8 (LE8) assessment. Retinopathy is determined through imaging assessment by professionals independently grading fundus photographs. Univariable and multivariable weighted logistic regression models, restricted cubic splines (RCS), subgroup analysis and weighted quantile sum (WQS) regression approaches were employed to assess the association between LE8 score-based CVH status and retinopathy. The mediation analysis was conducted to investigate whether serum albumin levels mediated the relationship between LE8 score and retinopathy.

RESULTS

In a fully adjusted logistic regression model, participants in the moderate and high CVH groups had a 39% (odds ratio (OR) 0.61, 95% confidence interval (CI) 0.43-0.87, P-value = 0.01) and 56% (OR 0.44, 95% CI 0.25-0.77, P-value < 0.001) lower odds of developing retinopathy compared to the low CVH group. The RCS model indicates a significant non-linear relationship between CVH and retinopathy. The WQS regression analysis suggests that blood glucose (47.65%) and blood pressure (19.41%) have the highest weights in relation to retinopathy. Mediation analysis suggests that serum albumin partially mediates the relationship between LE8 scores and retinopathy.

CONCLUSION

This study demonstrates a significant negative correlation between overall cardiovascular health measured by LE8 scores and retinopathy. Public health strategies that promote achieving optimal cardiovascular health indicators may help reduce the burden of retinal microvascular diseases.

Microvascular Dysfunction in Obesity-Hypertension

PURPOSE OF REVIEW

This review aims to explore the role of microvascular dysfunction in obesity-hypertension, discuss the effects obesity has on renal microvasculature, review the current methods for assessing microvascular dysfunction and available therapeutic options, and identify critical areas for further research.

RECENT FINDINGS

There is a strong association between obesity and hypertension. However, the pathophysiology of obesity-hypertension is not clear. Microvascular dysfunction has been linked to hypertension and obesity and could be an important mediator of obesity-related hypertension. Newer therapies for hypertension and obesity could have ameliorating effects on microvascular dysfunction, including GLP-1 agonists and SGLT-2 inhibitors. There is still much progress to be made in our understanding of the complex interplay between obesity, hypertension, and microvascular dysfunction. Continued efforts to understand microvascular dysfunction and its role in obesity-hypertension are crucial to develop precision therapy to target obesity-hypertension.

miRNA-22 is involved in the aortic reactivity in physiological conditions and mediates obesity-induced perivascular adipose tissue dysfunction

AIMS

Blood vessels are surrounded by perivascular adipose tissue (PVAT), which plays an important role in vascular tonus regulation due to its anticontractile effect; however, this effect is impaired in obesity. We previously demonstrated that miRNA-22 is involved in obesity-related metabolic disorders. However, the impact of miRNA-22 on vascular reactivity and PVAT function is unknown.

AIM

To investigate the role of miRNA-22 on vascular reactivity and its impact on obesity-induced PVAT dysfunction.

MAIN METHODS

Wild-type and miRNA-22 knockout (KO) mice were fed a control or a high-fat (HF) diet. To characterize the vascular response, concentration-responses curves to noradrenaline were performed in PVAT- or PVAT+ thoracic aortic rings in absence and presence of L-NAME. Expression of adipogenic and thermogenic markers and NOS isoforms were evaluated by western blotting or qPCR.

KEY FINDINGS

HF diet and miRNA-22 deletion reduced noradrenaline-induced contraction in PVAT- aortic rings. Additionally, miRNA-22 deletion increased noradrenaline-induced contraction in PVAT+ aortic rings without affecting its sensitivity; however, this effect was not observed in miRNA-22 KO mice fed a HF diet. Interestingly, miRNA-22 deletion reduced the contraction of aortic rings to noradrenaline via a NOS-dependent mechanism. Moreover, HF diet abolished the NOS-mediated anticontractile effect of PVAT, which was attenuated by miRNA-22 deletion. Mechanistically, we found that PVAT from miRNA-22 KO mice fed a HF diet presented increased protein expression of nNOS.

SIGNIFICANCE

These results suggest that miRNA-22 is important for aorta reactivity under physiological circumstances and its deletion attenuates the loss of the NOS-mediated anticontractile effect of PVAT in obesity.

Role of Perivascular Adipose Tissue in Aorta Reactivity from Obese and Hyperglycemic CD-1 Mice: New Insights into Perivascular Adipose Tissue

Background: Perivascular adipose tissue (PVAT) plays an essential role in cardiovascular homeostasis. However, during obesity and diabetes, its role in vascular tone regulation is unclear. This study aimed to evaluate the function of the PVAT on aorta reactivity in the lean and cafeteria (CAF) diet-induced obese-hyperglycemic mice model. Methods: Aorta reactivity to phenylephrine, KCl, and acetylcholine was analyzed in lean (n = 6) and obese mice (n = 6). Also, nitric oxide (NO-) and cyclooxygenase participation, in the presence (n = 6) and absence (n = 6) of PVAT, were examined in the aortas. Results: After a CAF diet for 19 weeks, obese mice showed increased body weight, glucose intolerance, and hypercholesterolemia concerning lean mice. Vascular reactivity to phenylephrine was reduced significantly in the aorta of obese mice. In contrast, the contraction produced by KCl (80 mM) was increased in the aorta of obese mice independent of PVAT. Acetylcholine-induced vasorelaxation diminished in the aortas of obese mice in the presence of PVAT. Nonselective inhibition of cyclooxygenases likely shows that PVAT and endothelium release vasorelaxant prostanoids. Conclusions: The results suggest that PVAT modulates aorta reactivity by releasing NO-, decreasing the α₁-adrenergic response to phenylephrine, and probably releasing vasorelaxant prostanoids. The data suggest that PVAT regulates the vascular smooth muscle and endothelial function in a CAF diet-induced obese-hyperglycemic mice model.

Lipid accumulation product as useful predictors of stroke: A correlation analysis between lipid accumulation index/cerebral vascular hemodynamics indexes and risk factors of stroke in 3264 people undergoing physical examination in Xinjiang

OBJECTIVE

To investigate the relationship between lipid accumulation index and cerebral hemodynamic integral value in 3264 people undergoing physical examination, so as to analyze the correlation between different lipid accumulation product index (LAP) levels and stroke risk factors.

METHODS

This cross-sectional study was conducted from January to December 2019 on 3264 adults at the age of 19 to 85 living in Urumqi, Xinjiang. The stroke related risk factors were evaluated by the questionnaire survey. The enrolled subjects were divided into Q1 group (n = 817), Q2 group (n = 815), Q3 group (n = 816) and Q4 group (n = 816) according to the quartile site at a low-to-high-score manner.

RESULTS

The proportion of males was significantly higher than that of females in Q2, Q3, and Q4 groups. The proportion of middle-aged people and the elderly in Q2, Q3, and Q4 groups was significantly higher than that of youths (P < .05). The proportion of patients with history of hypertension, hyperlipidemia, physical inactivity, and smoking, and the levels of systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, high-density cholesterol, low-density cholesterol, triglyceride, body mass index, waist circumference increased with the increase of LAP level in different groups (P < .05). On both sides of the cerebral hemodynamic integral value (CVHI) index, Vmean, Vmax, Vmin showed a decreasing trend whereas peripheral resistance, pulse velocity, Zcv, dynamic resistance, critical pressure level, difference between diastolic and critical pressure showed an increase trend with the increase of LAP level. The normal rate of CVHI in 4 groups (>75 points) was 97.4%, 89.7%, 87.0, and 80.8%, respectively, showing a decreasing trend. Logistic regression results showed that the higher the LAP, the higher the abnormal risk of CVHI.

CONCLUSION

There is a positive correlation between LAP and CVHI, the higher the LAP, the higher the risk of CVHI abnormality, which should be concerned seriously.

Effects of semaglutide on vascular structure and proteomics in high-fat diet-induced obese mice

BACKGROUND

Obesity is a chronic metabolic disease caused by a combination of genetic and environmental factors. To determine whether semaglutide could improve aortic injury in obese C57BL/6J mice, and further explore its molecular mechanism of action using proteomics.

METHODS

24 C57BL/6J male mice were randomly divided into normal diet group (NCD group), high-fat diet group (HFD group) and high-fat diet + semaglutide group (Sema group, semaglutide (30 nmol/kg/d) for 12 weeks). The serum samples were collected from mice to detect blood glucose, insulin and blood lipid concentrations. Aortic stiffness was detected by Doppler pulse wave velocity (PWV). Changes in vascular structure were detected by HE, masson, EVG staining and electron microscopy. The aorta-related protein expression profiles were detected by proteomic techniques, and proteins with potential molecular mechanisms were identified.

RESULTS

Semaglutide could reduce body weight, the concentrations of blood glucose, total cholesterol (TC), triglycerides (TG), lipoprotein cholesterol (LDL-C), and reduce the aortic PWV and ameliorate vascular damage in obese mice. The results of proteomic analysis showed there were 537 up-regulated differentially expressed proteins (DEPs) and 322 down-regulated DEPs in NCD/HFD group, 251 up-regulated DEPs and 237 down-regulated proteins in HFD/Sema group. There were a total of 25 meaningful overlapping DEPs in the NCD/HFD and HFD/Sema groups. GO enrichment analysis of overlapping DEPs found that these differential proteins were mainly located in the signaling pathways of the extracellular matrix. The most obvious changes of extracellular matrix associated proteins in the three experimental groups were Coll5a1, Lama4, Sparc.

CONCLUSION

Semaglutide may protect vascular structure and improve endothelial permeability by reducing the levels of Coll5a1, Lama4, Sparc in extracellular matrix, so as to improve vascular function and achieve vascular protection.

PPARγ as an indicator of vascular function in an experimental model of metabolic syndrome in rabbits

BACKGROUND AND AIMS

Underlying mechanisms associated with vascular dysfunction in metabolic syndrome (MetS) remain unclear and can even vary from one vascular bed to another.

METHODS

In this study, MetS was induced by a high-fat, high-sucrose diet, and after 28 weeks, aorta and renal arteries were removed and used for isometric recording of tension in organ baths, protein expression by Western blot, and histological analysis to assess the presence of atherosclerosis.

RESULTS

MetS induced a mild hypertension, pre-diabetes, central obesity and dyslipidaemia. Our results indicated that MetS did not change the contractile response in either the aorta or renal artery. Conversely, vasodilation was affected in both arteries in a different way. The aorta from MetS showed vascular dysfunction, including lower response to acetylcholine and sodium nitroprusside, while the renal artery from MetS presented a preserved relaxation to acetylcholine and an increased sensitivity to sodium nitroprusside. We did not find vascular oxidative stress in the aorta from MetS, but we found a significant decrease in PPARγ, phospho-Akt (p-Akt) and phospho-eNOS (p-eNOS) protein expression. On the other hand, we found oxidative stress in the renal artery from MetS, and PPARγ, Akt and p-Akt were overexpressed. No evidence of atherosclerosis was found in arteries from MetS.

CONCLUSIONS

MetS affects vascular function differently depending on the vessel. In the aorta, it decreases both the vasodilation and the expression of the PPARγ/Akt/eNOS pathway, while in the renal artery, it increases the expression of PPARγ/Akt signalling pathway without decreasing the vasodilation.

Constrained Mixture Models of Soft Tissue Growth and Remodeling - Twenty Years After

Soft biological tissues compromise diverse cell types and extracellular matrix constituents, each of which can possess individual natural configurations, material properties, and rates of turnover. For this reason, mixture-based models of growth (changes in mass) and remodeling (change in microstructure) are well-suited for studying tissue adaptations, disease progression, and responses to injury or clinical intervention. Such approaches also can be used to design improved tissue engineered constructs to repair, replace, or regenerate tissues. Focusing on blood vessels as archetypes of soft tissues, this paper reviews a constrained mixture theory introduced twenty years ago and explores its usage since by contrasting simulations of diverse vascular conditions. The discussion is framed within the concept of mechanical homeostasis, with consideration of solid-fluid interactions, inflammation, and cell signaling highlighting both past accomplishments and future opportunities as we seek to understand better the evolving composition, geometry, and material behaviors of soft tissues under complex conditions.

Differential Deleterious Impact of Highly Saturated Versus Monounsaturated Fat Intake on Vascular Function, Structure, and Mechanics in Mice

Vegetable oils such as palm oil (enriched in saturated fatty acids, SFA) and high-oleic-acid sunflower oil (HOSO, containing mainly monounsaturated fatty acids, MUFA) have emerged as the most common replacements for trans-fats in the food industry. The aim of this study is to analyze the impact of SFA and MUFA-enriched high-fat (HF) diets on endothelial function, vascular remodeling, and arterial stiffness compared to commercial HF diets. Five-week-old male C57BL6J mice were fed a standard (SD), a HF diet enriched with SFA (saturated oil-enriched Food, SOLF), a HF diet enriched with MUFA (unsaturated oil-enriched Food, UOLF), or a commercial HF diet for 8 weeks. Vascular function was analyzed in the thoracic aorta. Structural and mechanical parameters were assessed in mesenteric arteries by pressure myography. SOLF, UOLF, and HF diet reduced contractile responses to phenylephrine and induced endothelial dysfunction in the thoracic aorta. A significant increase in the β-index, and thus in arterial stiffness, was also detected in mesenteric arteries from the three HF groups, due to enhanced deposition of collagen in the vascular wall. SOLF also induced hypotrophic inward remodeling. In conclusion, these data demonstrate a deleterious effect of HF feeding on obesity-related vascular alterations that is exacerbated by SFA.

Oxidative Stress and Vascular Damage in the Context of Obesity: The Hidden Guest

The vascular system plays a central role in the transport of cells, oxygen and nutrients between different regions of the body, depending on the needs, as well as of metabolic waste products for their elimination. While the structure of different components of the vascular system varies, these structures, especially those of main arteries and arterioles, can be affected by the presence of different cardiovascular risk factors, including obesity. This vascular remodeling is mainly characterized by a thickening of the media layer as a consequence of changes in smooth muscle cells or excessive fibrosis accumulation. These vascular changes associated with obesity can trigger functional alterations, with endothelial dysfunction and vascular stiffness being especially common features of obese vessels. These changes can also lead to impaired tissue perfusion that may affect multiple tissues and organs. In this review, we focus on the role played by perivascular adipose tissue, the activation of the renin-angiotensin-aldosterone system and endoplasmic reticulum stress in the vascular dysfunction associated with obesity. In addition, the participation of oxidative stress in this vascular damage, which can be produced in the perivascular adipose tissue as well as in other components of the vascular wall, is updated.

Therapeutic Effects of Morinda citrifolia Linn. (Noni) Aqueous Fruit Extract on the Glucose and Lipid Metabolism in High-Fat/High-Fructose-Fed Swiss Mice

The aim of this study was to evaluate the therapeutic effects of two different doses (250 and 500 mg/kg) of Morinda citrifolia fruit aqueous extract (AE) in high-fat/high-fructose-fed Swiss mice. The food intake, body weight, serum biochemical, oral glucose tolerance test (OGTT), and enzyme-linked immunosorbent assay (ELISA), as well as histological analyses of the liver, pancreatic, and epididymal adipose tissue, were used to determine the biochemical and histological parameters. The chemical profile of the extract was determined by ultra-fast liquid chromatography–diode array detector–tandem mass spectrometry (UFLC–DAD–MS), and quantitative real-time PCR (qRT-PCR) was used to evaluate the gene expressions involved in the lipid and glucose metabolism, such as peroxisome proliferative-activated receptors-γ (PPAR-γ), -α (PPAR-α), fatty acid synthase (FAS), glucose-6-phosphatase (G6P), sterol regulatory binding protein-1c (SREBP-1c), carbohydrate-responsive element-binding protein (ChREBP), and fetuin-A. Seventeen compounds were tentatively identified, including iridoids, noniosides, and the flavonoid rutin. The higher dose of AE (AE 500 mg/kg) was demonstrated to improve the glucose tolerance; however, both doses did not have effects on the other metabolic and histological parameters. AE at 500 mg/kg downregulated the PPAR-γ, SREBP-1c, and fetuin-A mRNA in the liver and upregulated the PPAR-α mRNA in white adipose tissue, suggesting that the hypoglycemic effects could be associated with the expression of genes involved in de novo lipogenesis.

Modeling Diet-Induced Metabolic Syndrome in Rodents

Standardized animal models represent one of the most valuable tools available to understand the mechanism underlying the metabolic syndrome (MetS) and to seek for new therapeutic strategies. However, there is considerable variability in the studies conducted with this essential purpose. This review presents an updated discussion of the most recent studies using diverse experimental conditions to induce MetS in rodents with unbalanced diets, discusses the key findings in metabolic outcomes, and critically evaluates what we have been learned from them and how to advance in the field. The study includes scientific reports sourced from the Web of Science and PubMed databases, published between January 2013 and June 2020, which used hypercaloric diets to induce metabolic disorders, and address the impact of the diet on metabolic parameters. The collected data are used as support to discuss variables such as sex, species, and age of the animals, the most favorable type of diet, and the ideal diet length to generate metabolic changes. The experimental characteristics propose herein improve the performance of a preclinical model that resembles the human MetS and will guide researchers to investigate new therapeutic alternatives with confidence and higher translational validity.

Local Peroxynitrite Impairs Endothelial Transient Receptor Potential Vanilloid 4 Channels and Elevates Blood Pressure in Obesity

BACKGROUND

Impaired endothelium-dependent vasodilation is a hallmark of obesity-induced hypertension. The recognition that Ca2+ signaling in endothelial cells promotes vasodilation has led to the hypothesis that endothelial Ca2+ signaling is compromised during obesity, but the underlying abnormality is unknown. In this regard, transient receptor potential vanilloid 4 (TRPV4) ion channels are a major Ca2+ influx pathway in endothelial cells, and regulatory protein AKAP150 (A-kinase anchoring protein 150) enhances the activity of TRPV4 channels.

METHODS

We used endothelium-specific knockout mice and high-fat diet-fed mice to assess the role of endothelial AKAP150-TRPV4 signaling in blood pressure regulation under normal and obese conditions. We further determined the role of peroxynitrite, an oxidant molecule generated from the reaction between nitric oxide and superoxide radicals, in impairing endothelial AKAP150-TRPV4 signaling in obesity and assessed the effectiveness of peroxynitrite inhibition in rescuing endothelial AKAP150-TRPV4 signaling in obesity. The clinical relevance of our findings was evaluated in arteries from nonobese and obese individuals.

RESULTS

We show that Ca2+ influx through TRPV4 channels at myoendothelial projections to smooth muscle cells decreases resting blood pressure in nonobese mice, a response that is diminished in obese mice. Counterintuitively, release of the vasodilator molecule nitric oxide attenuated endothelial TRPV4 channel activity and vasodilation in obese animals. Increased activities of inducible nitric oxide synthase and NADPH oxidase 1 enzymes at myoendothelial projections in obese mice generated higher levels of nitric oxide and superoxide radicals, resulting in increased local peroxynitrite formation and subsequent oxidation of the regulatory protein AKAP150 at cysteine 36, to impair AKAP150-TRPV4 channel signaling at myoendothelial projections. Strategies that lowered peroxynitrite levels prevented cysteine 36 oxidation of AKAP150 and rescued endothelial AKAP150-TRPV4 signaling, vasodilation, and blood pressure in obesity. Peroxynitrite-dependent impairment of endothelial TRPV4 channel activity and vasodilation was also observed in the arteries from obese patients.

CONCLUSIONS

These data suggest that a spatially restricted impairment of endothelial TRPV4 channels contributes to obesity-induced hypertension and imply that inhibiting peroxynitrite might represent a strategy for normalizing endothelial TRPV4 channel activity, vasodilation, and blood pressure in obesity.

Involvement of inducible nitric oxide synthase and estrogen receptor ESR2 (ERβ) in the vascular dysfunction in female type 1 diabetic rats

AIMS

Inflammation is involved in diabetes-related vascular dysfunction. Estrogen receptor ESR2/ERβ induces the expression of inducible nitric oxide (NO) synthase (iNOS) and inflammation. The present study investigated the effect of alloxan-induced type 1 diabetes on the iNOS and ESR2 expression and the effect of the chronic iNOS inhibition on the vascular smooth muscle dysfunction in diabetic female rats. In addition, we evaluated the involvement of ESR2 in iNOS expression.

MAIN METHODS

Alloxan-induced diabetic female rats were treated or not with iNOS inhibitor (L-NIL). iNOS and ESR2 immunostaining, S-nitrosylated proteins and IL-1β protein expression in aorta and plasmatic NO levels were analyzed. Contractile response to noradrenaline was analyzed in endothelium-denuded aorta. iNOS mRNA expression was analyzed in isolated aortic smooth muscle cells (ASMCs) of female rats, incubated with 22 mM glucose and an ESR2 antagonist.

KEY FINDINGS

Aortic iNOS and ESR2 immunostaining, S-nitrosylated proteins, IL-1β protein expression and plasmatic NO levels were all increased, whereas noradrenaline-induced contraction was reduced in aorta of diabetic female rats. With the exception of iNOS and ESR2 immunostaining, all these parameters were corrected by L-NIL treatment. High glucose increased iNOS mRNA expression in ASMCs, which was reduced by an ESR2 antagonist.

SIGNIFICANCE

We demonstrated that increased iNOS-NO contributed to the impairment of the contractile response of aortic smooth muscle cells in female type 1 diabetic rats and that increased expression of iNOS may involve the participation of ESR2/ERβ.

Co-administration of conjugated linoleic acid and rosiglitazone increases atherogenic co-efficient and alters isoprenaline-induced vasodilatation in rats fed high fat diet

The cis(c)-9, trans(t)-11 (c9,t11) and t10,c12 isomers of conjugated linoleic acid (CLA) have been reported as agonists of peroxisome proliferator-activated receptor (PPAR) and beneficial in lipidemia and glycemia. However, it is unclear whether CLA isomers enhance or antagonize effects of conventional drugs targeting PPAR. Male Sprague-Dawley rats were fed high fat diet (HFD) for 8 weeks and treated without or with CLA, rosiglitazone or both for 4 weeks. Oral glucose tolerance and surrogate markers of insulin resistance were not significantly different for all treatments compared to untreated normal diet (ND) or HFD group, except lipoprotein levels. The combination of CLA and rosiglitazone had suppressed levels of low and high density lipoproteins (46 % and 25 %, respectively), compared to HFD-alone. Conversely, the atherogenic co-efficient of the animals received HFD or HFD+rosiglitazone+CLA was 2-folds higher than ND, HFD+rosiglitazone or HFD+CLA. Isolated aortic rings from the combined CLA and rosiglitazone treated animals were less sensitive to isoprenaline-induced relaxation among endothelium-denuded aortas with a decreased efficacy and potency (R(max)=53+/-4.7 %; pEC50=6+/-0.2) compared to endothelium-intact aortas (R(max)=100+/-9.9 %; pEC50=7+/-0.2). Our findings illustrate that the combination of CLA and rosiglitazone precede the atherogenic state with impaired endothelium-independent vasodilatation before the onset of HFD-induced insulin resistance.