Perivascular Adipose Research Articles

Perivascular adipose and perivascular nerve dysfunction in inflammatory bowel disease is reversed after macrophage depletion

Objective: Perivascular adipose tissue (PVAT) of mesenteric arteries (MAs) houses an array of immune cells and modulates vasomotor function. Changes in PVAT immune cell content and vasomotor effects are evident in cardiovascular diseases but have not been studied in Inflammatory Bowel Disease (IBD), where altered intestinal macrophage populations and impaired blood flow are evident. Thus, we hypothesized that (1) PVAT macrophage population expands with IBD, (2) IBD alters the role of PVAT in modulating sympathetic constriction and sensory dilation and (3) macrophage depletion improves PVAT and perivascular nerve function. Methods: Male and female IL10-/- mice were gavaged with H. hepaticus at weaning and developed IBD for 90d. Age-matched C57BL/6 mice served as controls. Mice then received two injections of PBS- or clodronate (CLOD)-containing liposomes to deplete macrophages. For immunofluorescence, MA PVAT was fixed, labeled for F4/80+ macrophages and confocally imaged. Fluorescence area was quantified and compared via nested one-way ANOVA. Perivascular nerve function was assessed using pressure myography of MAs. Sympathetic nerves were stimulated using electrical field stimulation (EFS, 50V, 1-16 Hz), and sensory nerves were stimulated (50V, 8 and 16Hz) in preconstricted arteries, with responses compared via two-way ANOVA. Results: IBD caused a ~200% increase in PVAT F4/80+ area (P<0.001). CLOD decreased F4/80+ area similar to Control-PBS and Control-CLOD PVAT levels (P=0.58 and 0.26). In cannulated MAs, sympathetic constrictions were similar in Control and IBD arteries -PVAT. In Control MAs, PVAT was anti-contractile: max EFS constriction decreased ~25% in +PVAT vs -PVAT arteries (P=0.005). PVAT became pro-contractile in IBD arteries, increasing max EFS constriction ~60% (P-0.004). Sympathetic constrictions were similar after CLOD vs PBS liposomes in Control -PVAT (P=0.54), Control +PVAT (P=0.80), or IBD -PVAT (P=0.77). In contrast, CLOD reversed PVAT pro-contractility in IBD-PBS +PVAT vs IBD-CLOD +PVAT arteries (P<0.001), decreasing max constriction ~25% back to Control levels. Subsequent studies measured sensory vasodilation in Control and IBD arteries +/- PVAT treated with PBS or CLOD. In Control-PBS, max sensory dilation was increased ~20% in +PVAT vs -PVAT arteries (P=0.02). IBD-PBS exhibited >75% decrease in max sensory vasodilation compared to Control in both -PVAT and +PVAT groups (P<0.001). CLOD significantly increased max sensory vasodilation ~250% in IBD -PVAT (P<0.001) and ~200% in IBD +PVAT (P<0.001), although neither group reached the max dilation of Control +/- PVAT. Conclusions: Macrophages accumulate in MA PVAT with IBD, causing it to become pro-contractile and impair perivascular sensory vasodilation. Macrophage depletion reverses PVAT pro-contractility and restored sensory vasodilation, making PVAT macrophages a potential target to restore impaired blood flow in IBD. R01HL157038, R00HL129196 to EMB This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Reciprocal communication of perivascular epicardial adipose tissue and coronary atherogenesis

Abstract Purpose Perivascular epicardial adipose tissue (PEAT) has been linked to underlying coronary artery disease (CAD) and proposed to modulate adjacent atherosclerotic plaque formation. In vitro and ex vivo studies support bilateral influence of adipose tissue and vessel wall. Therefore, we quantified PEAT volume and composition and its dynamics in a low coronary risk patient cohort with a semi-automate software in serial CT exams. Methods and materials We retrospectively included 120 patients (27% females) from a tertiary care hospital who underwent serial cardiac CT angiographies with a low cardiovascular risk profile. All coronary CTs were evaluated in a standardized approach: epicardial adipose tissue (EAT) volume and attenuation was quantified in total, in the atrioventricular (RCA, LCX) or interventricular (LAD) sulcus and in a 5mm radius for each coronary artery (PEAT). Coronary plaques were quantified using a semi-automated software and compared to progression, stability of regression between the two scans. The measurements were compared on a per-patient and per-vessel basis between plaque-naïve and diseased vessels. Results Of 120 patients (32% female), 59.2%) had atherosclerotic plaque formation. After 36 months mean follow-up, 22 (18.3%) showed a CAD regression plaques, 39 (32.5%) had stable coronary arteries and 49 (40.8%) progressive CAD. Total EAT volume decreased by −15.6±37.2 mm3 in the regressive group, increased by 2.7±30.6mm3 in the stable group and by 24.3±37.1mm3 in the progressive CAD group (p=0.003). Per-vessel analysis showed a significant decrease of perivascular EAT attenuation in patients with CAD regression (−3.8±7.6 HU) compared to CAD stable (1.2±9.1 HU) and CAD progressive patients (3.5±8.2 HU, p<0.0001). Mean sulcus EAT attenuation did not show a significant change at follow-up (p=0.135) Conclusion Epicardial adipose tissue volume is mutually changing with the progression or regression of coronary artery disease. Perivascular but not epicardial attenuation levels correlated to adjacent plaque and support a direct bilateral influence. Change per-vessel-basis (n=360) Funding Acknowledgement Type of funding source: None

Vascular Lipidomic Profiling of Potential Endogenous Fatty Acid PPAR Ligands Reveals the Coronary Artery as Major Producer of CYP450-Derived Epoxy Fatty Acids.

A number of oxylipins have been described as endogenous PPAR ligands. The very short biological half-lives of oxylipins suggest roles as autocrine or paracrine signaling molecules. While coronary arterial atherosclerosis is the root of myocardial infarction, aortic atherosclerotic plaque formation is a common readout of in vivo atherosclerosis studies in mice. Improved understanding of the compartmentalized sources of oxylipin PPAR ligands will increase our knowledge of the roles of PPAR signaling in diverse vascular tissues. Here, we performed a targeted lipidomic analysis of ex vivo-generated oxylipins from porcine aorta, coronary artery, pulmonary artery and perivascular adipose. Cyclooxygenase (COX)-derived prostanoids were the most abundant detectable oxylipin from all tissues. By contrast, the coronary artery produced significantly higher levels of oxylipins from CYP450 pathways than other tissues. The TLR4 ligand LPS induced prostanoid formation in all vascular tissue tested. The 11-HETE, 15-HETE, and 9-HODE were also induced by LPS from the aorta and pulmonary artery but not coronary artery. Epoxy fatty acid (EpFA) formation was largely unaffected by LPS. The pig CYP2J homologue CYP2J34 was expressed in porcine vascular tissue and primary coronary artery smooth muscle cells (pCASMCs) in culture. Treatment of pCASMCs with LPS induced a robust profile of pro-inflammatory target genes: TNFα, ICAM-1, VCAM-1, MCP-1 and CD40L. The soluble epoxide hydrolase inhibitor TPPU, which prevents the breakdown of endogenous CYP-derived EpFAs, significantly suppressed LPS-induced inflammatory target genes. In conclusion, PPAR-activating oxylipins are produced and regulated in a vascular site-specific manner. The CYP450 pathway is highly active in the coronary artery and capable of providing anti-inflammatory oxylipins that prevent processes of inflammatory vascular disease progression.

Beneficial Effects of Melatonin on Apolipoprotein-E Knockout Mice by Morphological and 18F-FDG PET/CT Assessments.

Atherosclerosis represents one of the main risk factors for the development of cardiovascular diseases. Their etiologies have been studied in recent years in order to better define therapeutic targets for intervention and to identify diagnostic methods. Two different subtypes of macrophages, M1 and M2, have been described in physiological conditions. They can also be found in the atherosclerotic process, where they both have opposite roles in disease progression. Perivascular brown adipose tissue is also involved in inflammation and endothelial damage. In this work, we provide insights into the protective role of melatonin in the atherosclerotic process by morphological and 18F-FDG-PET/CT analyses. In particular, we examined the effects of melatonin on pathways that are linked to atherosclerosis development. We showed that melatonin, by suppressing M1 activity, reduced inflammation and directed macrophage polarization toward the M2 macrophage subtype. Moreover, melatonin preserved the activity of perivascular brown adipose tissue. In addition, 18F-FDG uptake is very high in mice treated with melatonin, confirming that other factors may alter 18F-FDG distribution. In conclusion, we showed that melatonin affects inflammatory pathways that have been linked to atherosclerosis, assessed the relationships of the 18F-FDG PET/CT parameters with macrophage markers and the production of their cytokines, which that have been defined by morphological evaluations.

P3482Leptin, receptor to leptin and expression in adipocytes isolated from different adipose depots in patients with ischemic heart disease

Abstract Purpose To study the peculiarities of the content of leptin and the leptin receptor in adipocyte culture of subcutaneous (SAT), epicardial (EAT) and perivascular (PVAT) adipose tissue and the expression of their genes. Methods 29 patients with coronary heart disease were examined. Adipocytes were isolated from SAT, EAT and PVAT samples obtained during coronary artery bypass grafting, followed by evaluation (after 24 hours) of the leptin concentration (Human resistin ELISA, R&D Systems, USA) and leptin gene expression in cell culture. Magnetic resonance imaging (MRI) was used to determine the area of the visceral (VAT) and subcutaneous adipose tissue (SAT) of the abdominal region, the thickness of epicardial adipose tissue (EAT). The calculation of the free leptin index (FLI) was determined by the formula: leptin/SOB-R * 100. Leptin resistance was defined as an FLI >0.25. All study was carried out in compliance with the Helsinki Declaration, and its protocol was approved by the Ethical Committee of Research Institute. Statistical analysis was performed using Statistica 10.0. Results In adipocytes of EAT, leptin secretion was 1.2 times higher than in adipocytes of PVAT, which is consistent with the expression of the leptin gene. The content of leptin soluble receptor was opposite in the adipocytes of PVAT higher than in EAT and SAT 2.3 and 3.1 times, respectively. At the same time, the index of free leptin was higher in SAT adipocytes 1.3 and 3.2 times in comparison with EAT and PVAT. The correlation analysis confirmed the relationship between EAT thickness and the serum concentrations of leptin. Thus, in patients with VO, the leptin concentration had a negative dependence on the thickness of the left and right ventricle (r=−0.28, p=0.02; r=−0.33, p=0.02, respectively). A negative dependence on the EAT thickness was also established for the FLI (r=−0.28; p=0.03). PVAT of the abdominal aorta is similar to the properties of visceral AT. An analysis of the possible relationship between perivascular adipocytes and adipokine exchange rates showed a direct relationship between the volume PVAT of the abdominal aortic ventricle and leptin (r=0.44, p=0.01), as well as the FLI (r=0.56; p=0.03). Conclusion Adipocytes SAT, EAT and PVAT differed in the level of secretion of leptin. In epicardial and, to a greater extent, in perivascular adipocytes, a protective mechanism against a high concentration of leptin was observed due to increased secretion of the soluble receptor to leptin. The high content of leptin and the low soluble receptor for leptin led to the development of leptin resistance, which was more pronounced in the culture of adipocytes SAT. Meanwhile, the EAT thickness was inversely related to the concentration of leptin and the FLI index (one of the main leptin-resistance markers).

Characterization of thoracal fat depots - expression of adipokines and remodeling factors and impact of adipocyte conditioned media in fibroblast scratch assays.

Adipose tissue is not only a connective tissue but also an endocrine organ secreting adipokines like Leptin and Adiponectin, lipokines such as palmitoileic acid and extracellular vesicles. These factors and the expression of matrix remodeling enzymes impact surrounding tissues via paracrine effects. The expression of selected secretion factors and the effect of adipocyte conditioned media from four thoracal adipose tissue origins - subcutaneous, perivascular, pericardial and epicardial adipose tissues - in a fibroblast proliferation/wound healing scratch assay model were investigated. Results were compared directly and according to the type 2 diabetic mellitus (T2DM) status of the patients the tissues are originated from. Adipocyte conditioned media from non-diabetic patients resulted in a significant higher scratch closure rate compared to the media with T2DM background. Linoleic acid incubation in scratch assay resulted in a reduced scratch closure rate. Leptin, Adiponectin and Visfatin/Nampt expression and MMP2, MMP9 and FSTL1 mRNA levels did not vary according to T2DM subgroups directly, leading to the assumption that these factors are not causal for scratch assay effects observed. In contrast significant mRNA expression differences were monitored between the thoracal tissue origins implying variations in the local effects of the different adipose tissue depots.

Abstract P331: Transition From Pre-Diabetes To Diabetes Is Associated With Worsening Of Cardiac Autonomic Neuropathy: Reversal By Anti-Diabetic Drugs

Cardiac autonomic neuropathy (CAN) occurs early in the course of diabetes leading to significant cardiovascular mortality and morbidity. Manifested as impaired heart rate variability (HRV) and baroreflex sensitivity (BRS), CAN represents an independent risk predictor of cardiac mortality. CAN development is linked to hyperglycemia; however, current understanding extends cardiovascular risk to pre-diabetic patients with slight glycemic changes. Here, we assessed the incidence and manifestation of CAN in a rat model of metabolic challenge prior to and after the development of diabetes. Rats were fed a hypercaloric (HC) diet (4.035 KCal/g vs. 3 KCal/g for control rats) composed of: weight (calories) 18.06 % fat (38.68%), 15.8% protein (15.66%), and 46.13% carbohydrates (45.73%). Stable fasting hyperglycemia developed by 16 weeks of feeding. The pre-diabetic stage was associated with signs of perivascular and epicardiac adipose inflammation (4- and 40- fold increase in IL-1β and TGF-β and 2-fold increase in NK-κB expression; and macrophage infiltration) and increased brainstem oxidative stress accompanied with impairment of HRV (total power decrease from 3098 ± 233 to 89 ± 88μs 2 ) and the parasympathetic arm of the baroreflex (slope decrease from -1.02 ± 0.12 to -0.34 ± 0.04). These abnormalities were reversed upon treatment with non-hypoglycemic doses of either metformin or pioglitazone or upon lowering the rat caloric intake. On the other hand, after progression to diabetes, the autonomic deficit progressed to the sympathetic arm of the baroreflex (Slope reduction from -0.35 ± 0.02 to -0.09 ± 0.03). The same hypoglycemic doses of metformin and pioglitazone failed to reverse the impaired HRV and BRS. Whereas, reduction of hyperglycemia to control levels by insulin was only capable of reversing the sympathetic impairment (BRS slope of -0.28 ± 0.04). Our present results outline a framework for sequential involvement of different detrimental mechanisms in the course of metabolic disease leading to differential impact on cardiac autonomic control. Furthermore, our findings emphasize the value of early intervention with antidiabetic drugs with potential protective pleiotropic effects.

Hesperidin reverses perivascular adipose-mediated aortic stiffness with aging

We tested the hypothesis that hesperidin would reverse age-related aortic stiffness, perivascular adipose (PVAT) mediated-arterial stiffening and PVAT advanced glycation end-products (AGE) accumulation. Aortic pulse wave velocity (aPWV) and intrinsic mechanical stiffness, two measures of arterial stiffness, were assessed in C57BL/6 mice that were young (6months), old (27–29months), or old treated with hesperidin for 4weeks. Old compared with young mice had increased aPWV (444±10 vs. 358±8cm/s, P<0.05) and mechanical stiffness (6506±369 vs. 3664±414kPa, P<0.05). In old mice hesperidin reduced both aPWV (331±38cm/s) and mechanical stiffness (4445±667kPa) to levels not different from young. Aortic segments from old animals cultured with (+) PVAT had greater mechanical stiffness compared to young (+) PVAT (6454±323 vs. 3575±440kPa, P<0.05) that was ameliorated in arteries from old hesperidin treated cultured (+) PVAT (2639±258kPa). Hesperidin also reversed the aging-related PVAT AGE accumulation (all, P<0.05). A 4-week treatment with the AGE inhibitor aminoguanidine reversed both the age-related increase in aPWV (390±7cm/s) and mechanical stiffness (3396±1072kPa), as well as mechanical stiffness in arteries cultured (+) PVAT (3292±716kPa) (all, P<0.05) to values not different from young. In conclusion, hesperidin ameliorates the age-related increase in aortic stiffness and the PVAT-mediated effects on arterial stiffening. Hesperidin also reversed PVAT AGE accumulation, where PVAT AGE were shown to promote aortic stiffness with aging.

Regulation of Vascular Smooth Muscle Tone by Adipose-Derived Contracting Factor

Obesity and arterial hypertension, important risk factors for atherosclerosis and coronary artery disease, are characterized by an increase in vascular tone. While obesity is known to augment vasoconstrictor prostanoid activity in endothelial cells, less is known about factors released from fat tissue surrounding arteries (perivascular adipose). Using lean controls and mice with either monogenic or diet-induced obesity, we set out to determine whether and through which pathways perivascular adipose affects vascular tone. We unexpectedly found that in the aorta of obese mice, perivascular adipose potentiates vascular contractility to serotonin and phenylephrine, indicating activity of a factor generated by perivascular adipose, which we designated “adipose-derived contracting factor” (ADCF). Inhibition of cyclooxygenase (COX) fully prevented ADCF-mediated contractions, whereas COX-1 or COX-2-selective inhibition was only partially effective. By contrast, inhibition of superoxide anions, NO synthase, or endothelin receptors had no effect on ADCF activity. Perivascular adipose as a source of COX-derived ADCF was further confirmed by detecting increased thromboxane A2 formation from perivascular adipose-replete aortae from obese mice. Taken together, this study identifies perivascular adipose as a novel regulator of arterial vasoconstriction through the release of COX-derived ADCF. Excessive ADCF activity in perivascular fat under obese conditions likely contributes to increased vascular tone by antagonizing vasodilation. ADCF may thus propagate obesity-dependent hypertension and the associated increased risk in coronary artery disease, potentially representing a novel therapeutic target.