Effects of Weight Loss on Structural and Functional Alterations of Subcutaneous Small Arteries in Obese Patients

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.

Microcirculation in Hypertension: A Therapeutic Target to Prevent Cardiovascular Disease?

Arterial hypertension is a common condition worldwide and an important risk factor for cardio- and cerebrovascular events, renal diseases, as well as microvascular eye diseases. Established hypertension leads to the chronic vasoconstriction of small arteries as well as to a decreased lumen diameter and the thickening of the arterial media or wall with a consequent increased media-to-lumen ratio (MLR) or wall-to-lumen ratio (WLR). This process, defined as vascular remodeling, was firstly demonstrated in small resistance arteries isolated from subcutaneous biopsies and measured by micromyography, and this is still considered the gold-standard method for the assessment of structural alterations in small resistance arteries; however, microvascular remodeling seems to represent a generalized phenomenon. An increased MLR may impair the organ flow reserve, playing a crucial role in the maintenance and, probably, also in the progressive worsening of hypertensive disease, as well as in the development of hypertension-mediated organ damage and related cardiovascular events, thus possessing a relevant prognostic relevance. New non-invasive techniques, such as scanning laser Doppler flowmetry or adaptive optics, are presently under development, focusing mainly on the evaluation of WLR in retinal arterioles; recently, also retinal microvascular WLR was demonstrated to have a prognostic impact in terms of cardio- and cerebrovascular events. A rarefaction of the capillary network has also been reported in hypertension, which may contribute to flow reduction in and impairment of oxygen delivery to different tissues. These microvascular alterations seem to represent an early step in hypertension-mediated organ damage since they might contribute to microvascular angina, stroke, and renal dysfunction. In addition, they can be markers useful in monitoring the beneficial effects of antihypertensive treatment. Additionally, conductance arteries may be affected by a remodeling process in hypertension, and an interrelationship is present in the structural changes in small and large conductance arteries. The review addresses the possible relations between structural microvascular alterations and hypertension-mediated organ damage, and their potential improvement with antihypertensive treatment.

The renal resistive index is associated with microvascular remodeling in patients with severe obesity

BACKGROUND

Renal hemodynamics is impaired since the early stage of cardiometabolic disease. However, in obesity, its noninvasive ultrasound assessment still fails to provide pathophysiologic and clinical meaningfulness. We aimed to explore the relationship between peripheral microcirculation and renal hemodynamics in severe obesity.

METHODS

We enrolled fifty severely obese patients with an indication for bariatric referring to our outpatient clinic. Patients underwent an extensive reno-metabolic examination, paired with Doppler ultrasound and measurement of the renal resistive index (RRI). On the day of the surgery, visceral fat biopsies were collected to perform an ex-vivo complete microcirculatory assessment. Media-to-lumen ratio (M/L) and vascular response to acetylcholine (ACh), alone or co-incubated with N G -nitro arginine methyl ester (L-NAME), were measured.

RESULTS

Patients were stratified according to their normotensive (NT) or hypertensive (HT) status. HT had lower estimated glomerular filtration rate and higher RRI compared to NT, while the presence and extent of albuminuria were similar between the two groups. Concerning microcirculatory assessment, there were no differences between groups as regards the microvascular structure, while the vasorelaxation to ACh was lower in HT ( P = 0.042). Multivariable analysis showed a relationship between M/L and RRI ( P  = 0.016, St. β 0.37) and between albuminuria and the inhibitory response of L-NAME to Ach vasodilation ( P   =  0.036, St. β = -0.34). Notably, all these correlations were consistent also after adjustment for confounding factors.

CONCLUSIONS

The RRI and albuminuria relationship with microvascular remodeling in patients affected by severe obesity supports the clinical implementation of RRI to improve risk stratification in obesity and suggests a tight pathophysiologic connection between renal haemodynamics and microcirculatory disruption.

Sleeve gastrectomy improved microvascular phenotypes from obesity cohort, detected with optical coherence tomography angiography

AIMS

To examine how metabolic status is associated with microvascular phenotype and to identify variables associated with vascular remodeling after bariatric surgery, using noninvasive optical coherence tomography angiography (OCTA).

METHODS

The study included 136 obese subjects scheduled for bariatric surgery and 52 normal-weight controls. Patients with obesity were divided into metabolically healthy obesity (MHO) and metabolic syndrome (MetS) groups according to the diagnosis criteria of the Chinese Diabetes Society. Retinal microvascular parameters were measured by OCTA, including superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel densities. Follow-ups were performed at the baseline and 6 months after bariatric surgery.

RESULTS

Fovea SCP, average DCP, fovea DCP, parafovea DCP, and perifovea DCP vessel densities were significantly lower in the MetS group, compared to controls (19.91% vs. 22.49%, 51.60% vs. 54.20%, 36.64% vs. 39.14%, 56.24% vs. 57.65% and 52.59% vs. 55.58%, respectively, all p < .05). Parafovea SCP, average DCP, parafovea DCP, and perifovea DCP vessel densities significantly improved in patients with obesity 6 months after surgery, compared to baseline (54.21% vs. 52.97%, 54.43% vs. 50.95%, 58.29% vs. 55.54% and 55.76% vs. 51.82%, respectively, all p < .05). Multivariable analyses showed that baseline blood pressure and insulin were independent predictors of vessel density changes 6 months after surgery.

CONCLUSIONS

Retinal microvascular impairment occurred mainly in MetS rather than MHO patients. Retinal microvascular phenotype improved 6 months after bariatric surgery and baseline blood pressure and insulin status may be key determinants. OCTA may be a reliable method to evaluate the microvascular complications associated with obesity.

Challenges in the evaluation of endothelial cell dysfunction: a statement from the European Society of Hypertension Working Group on Endothelin and Endothelial Factors

Endothelial cell function is mediated by different mechanisms in different vascular beds. Moreover, in humans, endothelial cell dysfunction triggers and accelerates the progression of cardiovascular and chronic kidney diseases. Progression of such diseases can be in part mitigated by the control of cardiovascular risk factors and drugs targeting different systems, including endothelin receptor antagonists (ERAs), renin-angiotensin aldosterone antagonists and agents affecting glucose metabolism, all of which were shown to improve endothelial cell function. In recent years, the microRNAs, which are endogenous regulators of gene expression, have been identified as transmitters of information from endothelial cells to vascular smooth muscle cells, suggesting that they can entail tools to assess the endothelial cell dysfunction in arterial hypertension and target for pharmacologic intervention. This article critically reviews current challenges and limitations of available techniques for the invasive and noninvasive assessment of endothelial cell function, and also discusses therapeutic aspects as well as directions for future research in the areas of endothelial cell biology and pathophysiology in humans.

State of the Art Review: Vascular Remodeling in Hypertension

Although the gold-standard method for the assessment of structural alteration in small resistance arteries is the evaluation of the MLR by micromyography in bioptic tissues, new, noninvasive techniques are presently under development, focusing mainly on the evaluation of WLR in retinal arterioles. These approaches represent a promising and interesting future perspective. Appropriate antihypertensive treatment is able to prevent the development of microvascular alterations or to induce their regression. Also, conductance arteries may be affected by a remodeling process in hypertension, and a cross-talk may exist between structural changes in the small and large arteries. In conclusion, the evaluation of microvascular structure is ready for clinical prime time, and it could, in the future, represent an evaluation to be performed in the majority of hypertensive patients, to better stratify cardiovascular risk and better evaluate the effects of antihypertensive therapy. However, for this purpose, we need a clear demonstration of the prognostic relevance of noninvasive measures of microvascular structure, in basal conditions and during treatment. Vascular remodeling may be frequently observed in hypertension, as well as in obesity and diabetes mellitus. An increased media to lumen ratio (MLR) or wall to lumen ratio (WLR) in microvessels is the hallmark of hypertension, and may impair organ flow reserve, being relevant in the maintenance and, probably, also in the progressive worsening of hypertensive disease, as well as in the development of hypertension-mediated organ damage/cardiovascular events. The molecular mechanisms underlying the development of vascular remodeling are only partly understood.

Targeting SIRT1 Rescues Age- and Obesity-Induced Microvascular Dysfunction in Ex Vivo Human Vessels

BACKGROUND

Experimental evidence suggests a key role of SIRT1 (silent information regulator 1) in age- and metabolic-related vascular dysfunction. Whether these effects hold true in the human microvasculature is unknown. We aimed to investigate the SIRT1 role in very early stages of age- and obesity-related microvascular dysfunction in humans.

METHODS

Ninety-five subjects undergoing elective laparoscopic surgery were recruited and stratified based on their body mass index status (above or below 30 kg/m²) and age (above or below 40 years) in 4 groups: Young Nonobese, Young Obese, Old Nonobese, and Old Obese. We measured small resistance arteries' endothelial function by pressurized micromyography before and after incubation with a SIRT1 agonist (SRT1720) and a mitochondria reactive oxygen species (mtROS) scavenger (MitoTEMPO). We assessed vascular levels of mtROS and nitric oxide availability by confocal microscopy and vascular gene expression of SIRT1 and mitochondrial proteins by qPCR. Chromatin immunoprecipitation assay was employed to investigate SIRT1-dependent epigenetic regulation of mitochondrial proteins.

RESULTS

Compared with Young Nonobese, obese and older patients showed lower vascular expression of SIRT1 and antioxidant proteins (FOXO3 [forkhead box protein O3] and SOD2) and higher expression of pro-oxidant and aging mitochondria proteins p66^Shc and Arginase II. Old Obese, Young Obese and Old Nonobese groups endothelial dysfunction was rescued by SRT1720. The restoration was comparable to the one obtained with mitoTEMPO. These effects were explained by SIRT1-dependent chromatin changes leading to reduced p66^Shc expression and upregulation of proteins involved in mitochondria respiratory chain.

CONCLUSIONS

SIRT1 is a novel central modulator of the earliest microvascular damage induced by age and obesity. Through a complex epigenetic control mainly involving p66^Shc and Arginase II, it influences mtROS levels, NO availability, and the expression of proteins of the mitochondria respiratory chain. Therapeutic modulation of SIRT1 restores obesity- and age-related endothelial dysfunction. Early targeting of SIRT1 might represent a crucial strategy to prevent age- and obesity-related microvascular dysfunction.

Enabling Wearable Pulse Transit Time-Based Blood Pressure Estimation for Medically Underserved Areas and Health Equity: Comprehensive Evaluation Study

BACKGROUND

Noninvasive and cuffless approaches to monitor blood pressure (BP), in light of their convenience and accuracy, have paved the way toward remote screening and management of hypertension. However, existing noninvasive methodologies, which operate on mechanical, electrical, and optical sensing modalities, have not been thoroughly evaluated in demographically and racially diverse populations. Thus, the potential accuracy of these technologies in populations where they could have the greatest impact has not been sufficiently addressed. This presents challenges in clinical translation due to concerns about perpetuating existing health disparities.

OBJECTIVE

In this paper, we aim to present findings on the feasibility of a cuffless, wrist-worn, pulse transit time (PTT)-based device for monitoring BP in a diverse population.

METHODS

We recruited a diverse population through a collaborative effort with a nonprofit organization working with medically underserved areas in Georgia. We used our custom, multimodal, wrist-worn device to measure the PTT through seismocardiography, as the proximal timing reference, and photoplethysmography, as the distal timing reference. In addition, we created a novel data-driven beat-selection algorithm to reduce noise and improve the robustness of the method. We compared the wearable PTT measurements with those from a finger-cuff continuous BP device over the course of several perturbations used to modulate BP.

RESULTS

Our PTT-based wrist-worn device accurately monitored diastolic blood pressure (DBP) and mean arterial pressure (MAP) in a diverse population (N=44 participants) with a mean absolute difference of 2.90 mm Hg and 3.39 mm Hg for DBP and MAP, respectively, after calibration. Meanwhile, the mean absolute difference of our systolic BP estimation was 5.36 mm Hg, a grade B classification based on the Institute for Electronics and Electrical Engineers standard. We have further demonstrated the ability of our device to capture the commonly observed demographic differences in underlying arterial stiffness.

CONCLUSIONS

Accurate DBP and MAP estimation, along with grade B systolic BP estimation, using a convenient wearable device can empower users and facilitate remote BP monitoring in medically underserved areas, thus providing widespread hypertension screening and management for health equity.

Gastric Bypass Improves Microvascular Perfusion in Patients with Obesity

PURPOSE

Basic science research has shown that obesity is associated with microvascular endothelial dysfunction. However, whether bariatric surgery impacts the microvascular networks has yet to be explored. This study sought to evaluate the impact of gastric bypass in the retinal microvasculature.

METHODS

Patients with obesity (BMI ≥ 35 kg/m²) scheduled to gastric bypass were consecutively recruited and included in the study. Patients were evaluated before surgery and 6-12 months after the intervention. Macular microvascular properties were evaluated using optical coherence tomography (OCT) angiography. Foveal avascular zone area, perimeter, circularity, and foveal and perifoveal vascular density (in both superficial and deep vascular plexus) were computed.

RESULTS

In total, 40 eyes from 20 patients were included (30% male, mean BMI 43.4 ± 4.5 kg/m² (range 35.7-51.4). From these, 45% were diabetic before bariatric surgery. After surgery, there was a significant increase in foveal avascular zone circularity (from 0.85 ± 0.09 to 0.92 ± 0.07, p = 0.001) and vascular density in perifoveal deep vascular plexus (from 0.69 ± 0.12 to 0.73 ± 0.12; p = 0.04), whereas foveal avascular zone perimeter decreased (from 2.34 ± 0.37 to 2.20 ± 0.35 mm, p = 0.007). Preoperative diabetic status was not a predictor of microvascular retinal changes after bariatric surgery. However, after multivariate adjustments, the increased drop in HbA1c after the surgery remained associated with the increase in perifoveal vascular density in the deep vascular plexus (B = 0.05; 95% CI 0.05-0.10; p = 0.03).

CONCLUSIONS

Gastric bypass improves retinal microvascular perfusion as demonstrated by the increased parafoveal vascular density in the deep vascular plexus, increased foveal avascular zone circularity, and decreased foveal avascular zone perimeter.

Post-occlusive reactive hyperemic response of skin microcirculation among extremely obese patients in the short and long term after bariatric surgery

OBJECTIVE

To assess changes of post-occlusive reactive hyperemic response in skin microcirculation among extremely obese patients 10 days and 6 months after bariatric surgery for patients with and without hypertension.

METHODS

Skin blood flow was measured using PeriFlux laser Doppler fluxmetry. Data were analyzed in the entire group and two subgroups: with and without hypertension.

RESULTS

Data from 88 patients (mean age 42.1 ± 11.2 years, 40.5% men) were analyzed. Six months after bariatric surgery, the time to reach peak flows had been shortened (2.4 ± 1.7 vs 2.1 ± 1.0 seconds, P < .05) and the area of hyperemia had increased (1027 ± 791 vs 1386 ± 699 AU*s, P < .05). The total power of post-occlusive reactive hyperemic after occlusion had been augmented mainly with power intensification of endothelial and myogenic origin. Post-occlusive reactive hyperemic parameters had changed mainly in the subgroup with hypertension. Variations of anthropometric parameters, metabolic characteristic, and adipokines mainly influenced on studied hyperemic flow parameters variations after the intervention in multiple regression analysis.

CONCLUSION

Cutaneous post-occlusive reactive hyperemic reactivity in time and frequency domains improved 6 months after bariatric surgery, and improvements in microvascular function were observed mainly in patients with hypertension. Variations of anthropometric parameters, metabolic characteristics, and adipokines had influence on hyperemic flow reactivity.

Microvascular Endothelial Dysfunction in Human Obesity: Role of TNF-α

CONTEXT

Endothelium guarantees vascular homeostasis by the opposite action of substances by vasodilating/antithrombogenic and vasoconstricting/prothrombotic activities. Obesity is characterized by endothelial dysfunction associated with a condition of vascular low-grade inflammation.

EVIDENCE ACQUISITION

Analysis of available basic or clinical papers published in peer-reviewed international journals on microcirculation and obesity.

EVIDENCE SYNTHESIS

Vascular low-grade inflammation, which characterizes obesity, is secondary to abnormal production of proinflammatory cytokines, including TNF-α. TNF-α, generated either in small vessels or within the perivascular adipose tissue (PVAT) of patients with obesity, stimulates reactive oxygen species generation, mainly through NAD(P)H oxidase activation, which in turn reduces nitric oxide (NO) availability. These aspects are highlighted by the insulin resistance status and macronutrient intake that characterize the obesity condition. Oxidant excess has also been proposed as a mechanism whereby TNF-α interferes with the endothelin-1/NO system at the level of small vessels from patients with obesity.

CONCLUSIONS

In obesity, microvasculature from visceral fat is an important source of low-grade inflammation and oxidative stress that, together with the PVAT, directly contribute to vascular changes, favoring the development and acceleration of the vascular atherothrombotic process in this clinical condition.

Causal association of body mass index with hypertension using a Mendelian randomization design

Observational studies have shown that obesity is a major risk factor for hypertension, but unmeasured confounding factors may exist. We used Mendelian randomization (MR) to assess the causal effect of obesity on hypertension.The MR analysis was performed in a well-defined community cohort study of 8832 middle-aged (40-69 years) adults in Korea enrolled from 2001 to 2013. We used baseline hypertension and newly diagnosed hypertension during the 10-year follow-up period as the outcome variable. Genetic risk score associated with body mass index (BMI GRS) was used as the instrumental variable (IV) to measure the causal relationship between obesity and hypertension. The IV estimate of causal odds ratio (OR) was derived using the Wald ratio estimator and then exponentiation to express the result as an OR.In the multivariable model adjusting for age, sex, study area, education, smoking, and current alcohol consumption, each 1 kg/m increase in BMI was associated with a 19% (OR: 1.19, 95% confidence interval [CI]: 1.17-1.21) increase in hypertension risk. We selected 6 single-nucleotide polymorphisms (P < 1.0 × 10) associated with BMI by genome-wide screening using linear regression and created 6 types of GRS. We demonstrated that each standard-deviation increase in BMI GRS was associated with a 5% to 6% (OR: 1.05-1.06) increased risk of hypertension (all P < .05). Using BMI GRS as the IV, we found a causal relationship between BMI and hypertension (OR: 1.13-1.26, all P < .05 except weighted GRS [n = 6]).Using Mendelian randomization, we found that obesity is causally associated with hypertension. This information will have important public health implications, supporting evidence that obesity-reduction programs will reduce the incidence of hypertension.

Decreased circulating T regulatory lymphocytes in obese patients undergoing bariatric surgery

OBJECTIVE

It has been previously demonstrated that T lymphocytes may be involved in the development of hypertension and microvascular remodeling, and that circulating T effector lymphocytes may be increased in hypertension. In particular, Th1 and Th 17 lymphocytes may contribute to the progression of hypertension and microvascular damage while T-regulatory (Treg) lymphocytes seem to be protective in this regard. However, no data is available about patients with severe obesity, in which pronounced microvascular alterations were observed.

DESIGN AND METHODS

We have investigated 32 severely obese patients undergoing bariatric surgery, as well as 24 normotensive lean subjects and 12 hypertensive lean subjects undergoing an elective surgical intervention. A peripheral blood sample was obtained before surgery for assessment of CD4+ T lymphocyte subpopulations. Lymphocyte phenotype was evaluated by flow cytometry in order to assess T-effector and Treg lymphocytes.

RESULTS

A marked reduction of several Treg subpopulations was observed in obese patients compared with controls, together with an increased in CD4+ effector memory T-effector cells.

CONCLUSION

In severely obese patients, Treg lymphocytes are clearly reduced and CD4+ effector memory cells are increased. It may be hypothesized that they might contribute to the development of marked microvascular alterations previously observed in these patients.

Age- and Sex-Specific Reference Values for Media/Lumen Ratio in Small Arteries and Relationship With Risk Factors

Small-artery remodeling is an early feature of target organ damage in hypertension and retains a negative prognostic value. The aim of the study is to establish age- and sex-specific reference values for media/lumen in small arteries obtained in humans by biopsy. Data from 91 healthy individuals and 200 individuals with cardiovascular risk factors in primary prevention from 4 Italian centers were pooled. Sex-specific equations for media/lumen in the healthy subpopulation, with age as dependent variable, were calculated. These equations were used to calculate predicted media/lumen values in individuals with risk factors and Z scores. The association between classical risk factors and Z scores was then explored by multiple regression analysis. A second-degree polynomial equation model was chosen to obtain sex-specific equations for media/lumen, with age as dependent variable. In the population with risk factors (111 men, age 50.5±14.0 years, hypertension 80.5%), media/lumen Z scores were independently associated with body mass index (standardized β=0.293, P=0.0001), total cholesterol (β=0.191, P=0.031), current smoking (β=0.238, P=0.0005), fasting blood glucose (β=0.204, P=0.003), systolic blood pressure (β=0.233, P=0.023), and female sex (β=0.799, P=0.038). A significant interaction between female sex and total cholesterol was found (β=-0.979, P=0.014). Results were substantially similar in the hypertensive subgroup. A method to calculate individual values of remodeling and growth index based on reference values was also presented. Age- and sex-specific percentiles of media/lumen in a healthy population were estimated. In a predominantly hypertensive population, media/lumen Z scores were associated with major cardiovascular risk factors, including body mass index, cholesterol, smoking, glucose, and systolic blood pressure. Significant sex differences were observed.

Combined exercise reduces arterial stiffness, blood pressure, and blood markers for cardiovascular risk in postmenopausal women with hypertension

OBJECTIVE

Postmenopausal women exhibit elevated brachial-ankle pulse wave velocity (baPWV), an indicator of arterial stiffness, which is associated with an increased risk of cardiovascular events and mortality. The purpose of this study is to examine the impact of combined resistance and aerobic exercise training on baPWV, blood pressure (BP), and cardiovascular fitness in postmenopausal women with stage 1 hypertension.

METHODS

Twenty postmenopausal women (age, 75 ± 2 y; systolic BP, 152 ± 2 mm Hg, diastolic BP, 95 ± 3 mm Hg) were randomly assigned to a "no-exercise" (CON, n = 10) or combined exercise (EX, n = 10) group. The EX group performed resistance and aerobic exercise for 12 weeks, 3 times per week. Exercise intensity was increased gradually, from 40% to 70% of heart rate reserve, every 4 weeks. BaPWV, BP, blood nitrite/nitrate, endothelin-1 (ET-1), cardiovascular fitness, and body composition were measured before and after the 12-week intervention.

RESULTS

BP, baPWV (-1.2 ± 0.4 m/s), ET-1 (-2.7 ± 0.3 μmol/mL), nitrite/nitrate (+4.5 ± 0.5 μM), functional capacity, and body composition were significantly improved (P < 0.05) in the EX group after 12 weeks of training, but no changes were observed in the CON group.

CONCLUSIONS

These findings indicate that 12 weeks of combined exercise training improves arterial stiffness, BP, ET-1, blood nitrite/nitrate, functional capacity, and body composition in postmenopausal women with stage 1 hypertension. Thus, this study provides evidence that combined exercise training is a useful therapeutic method to improve cardiovascular health which can reduce cardiovascular disease risk in postmenopausal women with hypertension.

Microvascular structure as a prognostically relevant endpoint

Remodelling of subcutaneous small resistance arteries, as indicated by an increased media-to-lumen ratio, is frequently present in hypertensive, obese, or diabetic patients. The increased media-to-lumen ratio may impair organ flow reserve. This may be important in the maintenance and, probably, also in the progressive worsening of hypertensive disease. The presence of structural alterations represents a prognostically relevant factor, in terms of development of target organ damage or cardiovascular events, thus allowing us a prediction of complications in hypertension. In fact, media-to-lumen ratio of small arteries at baseline, and possibly their changes during treatment may have a strong prognostic significance. However, new, non-invasive techniques are needed before suggesting extensive application of the evaluation of remodelling of small arteries for the cardiovascular risk stratification in hypertensive patients. Some new techniques for the evaluation of microvascular morphology in the retina, currently under clinical investigation, seem to represent a promising and interesting future perspective. The evaluation of microvascular structure is progressively moving from bench to bedside, and it could represent, in the near future, an evaluation to be performed in all hypertensive patients, to obtain a better stratification of cardiovascular risk, and, possibly, it might be considered as an intermediate endpoint in the evaluation of the effects of antihypertensive therapy, provided that a demonstration of a prognostic value of non-invasive measures of microvascular structure is made available.

Imaging and modeling of acute pressure-induced changes of collagen and elastin microarchitectures in pig and human resistance arteries

The impact of disease-related changes in the extracellular matrix (ECM) on the mechanical properties of human resistance arteries largely remains to be established. Resistance arteries from both pig and human parietal pericardium (PRA) display a different ECM microarchitecture compared with frequently used rodent mesenteric arteries. We hypothesized that the biaxial mechanics of PRA mirror pressure-induced changes in the ECM microarchitecture. This was tested using isolated pig PRA as a model system, integrating vital imaging, pressure myography, and mathematical modeling. Collagenase and elastase digestions were applied to evaluate the load-bearing roles of collagen and elastin, respectively. The incremental elastic modulus linearly related to the straightness of adventitial collagen fibers circumferentially and longitudinally (both R2 ≥ 0.99), whereas there was a nonlinear relationship to the internal elastic lamina elastin fiber branching angles. Mathematical modeling suggested a collagen recruitment strain (means ± SE) of 1.1 ± 0.2 circumferentially and 0.20 ± 0.01 longitudinally, corresponding to a pressure of ~40 mmHg, a finding supported by the vital imaging. The integrated method was tested on human PRA to confirm its validity. These showed limited circumferential distensibility and elongation and a collagen recruitment strain of 0.8 ± 0.1 circumferentially and 0.06 ± 0.02 longitudinally, reached at a distending pressure below 20 mmHg. This was confirmed by vital imaging showing negligible microarchitectural changes of elastin and collagen upon pressurization. In conclusion, we show here, for the first time in resistance arteries, a quantitative relationship between pressure-induced changes in the extracellular matrix and the arterial wall mechanics. The strength of the integrated methods invites for future detailed studies of microvascular pathologies.

NEW & NOTEWORTHY This is the first study to quantitatively relate pressure-induced microstructural changes in resistance arteries to the mechanics of their wall. Principal findings using a pig model system were confirmed in human arteries. The combined methods provide a strong tool for future hypothesis-driven studies of microvascular pathologies.

Exploring Vascular Function Biomarkers: Implications for Rehabilitation

The endothelium plays an important role in maintaining vascular homeostasis and regulating blood vessel function. Endothelial function is considered an independent predictor for risk of future cardiovascular events in cardiovascular and non-cardiovascular patients, as well as a predictor for postoperative complications in cardiovascular surgery patients. Brachial artery flow-mediated dilation by high-resolution ultrasound is widely used to evaluate endothelium-dependent vasodilation, which is mainly mediated by nitric oxide release. Physical exercise exerts beneficial effects on endothelial function and can be used in both primary and secondary prevention of cardiac and peripheral artery diseases, even in the postoperative period of cardiovascular surgery.

Abnormal Remodeling of Subcutaneous Small Arteries Is Associated With Early Diastolic Impairment in Metabolic Syndrome

Background

Small artery pathophysiology is frequently invoked as a cause of obesity‐related diastolic heart failure. However, evidence to support this hypothesis is scant, particularly in humans.

Methods and Results

To address this, we studied human small artery structure and function in obesity and looked for correlations between vascular parameters and diastolic function. Seventeen obese patients with metabolic syndrome and 5 control participants underwent echocardiography and subcutaneous gluteal fat biopsy. Small arteries were isolated from the biopsy and pressure myography was used to study endothelial function and wall structure. In comparison with the control group, small arteries from obese participants exhibited significant endothelial dysfunction, assessed as the vasodilatory response to acetylcholine and also pathological growth of the wall. For the obese participants, multiple regression analysis revealed an association between left atrial volume and both the small artery wall thickness (β=0.718, P=0.02) and wall‐to‐lumen ratio (β=0.605, P=0.02). Furthermore, the E:E′ ratio was associated with wall‐to‐lumen ratio (β=0.596, P=0.02) and inversely associated with interleukin‐6 (β=−0.868, P=0.03). By contrast, endothelial function did not correlate with any of the echocardiographic parameters studied.

Conclusions

Although the small arteries studied were not cardiac in origin, our results support a role for small artery remodeling in the development of diastolic dysfunction in humans. Further direct examination of the structure and function of the myocardial resistance vasculature is now warranted, to elucidate the temporal association between metabolic risk factors, small artery injury, and diastolic impairment.

Current Understanding of Atherogenesis

Scientific understanding of atherogenesis is constantly developing. From Virchow's observations 160 years ago we now recognize the endothelial response to injury as inflammatory, involved in all stages of atherosclerosis. Endothelial activation may cause reversible injury or dysfunction, or lead to irreparable damage. Indeed, early atherosclerosis is reversible. The introduction of genome-wide association testing has furthered the identification of potentially important genetic variants that help explain the heritability of coronary artery disease as well as spontaneous cases of severe coronary artery disease in patients with otherwise minimal risk factors. However, the mechanisms by which many of the newer variants exert their influence remain unknown.

Relationship between different subpopulations of circulating CD4+ T lymphocytes and microvascular or systemic oxidative stress in humans

BACKGROUND AND OBJECTIVE

Different components of the immune system, including innate and adaptive immunity (T effector lymphocytes and T regulatory lymphocytes - TREGs) may be involved in the development of hypertension, vascular injury and inflammation. However, no data are presently available in humans about possible relationships between T-lymphocyte subtypes and microvascular oxidative stress. Our objective was to investigate possible relationships between T-lymphocyte subtypes and systemic and microvascular oxidative stress in a population of normotensive subjects and hypertensive patients.

PATIENTS AND METHODS

In the present study we enrolled 24 normotensive subjects and 12 hypertensive patients undergoing an elective surgical intervention. No sign of local or systemic inflammation was present. All patients underwent a biopsy of subcutaneous fat during surgery. A peripheral blood sample was obtained before surgery for assessment of T lymphocyte subpopulations by flow cytometry and circulating indices of oxidative stress.

RESULTS

A significant direct correlation was observed between Th1 lymphocytes and reactive oxygen species (ROS) production (mainly in microvessels). Additionally, significant inverse correlations were observed between ROS and total TREGs, or TREGs subtypes. Significant correlations were detected between circulating indices of oxidative stress/inflammation and indices of microvascular morphology/Th1 and Th17 lymphocytes. In addition, a significant inverse correlation was detected between TREGs in subcutaneous small vessels and C reactive protein.

CONCLUSIONS

Our data suggest that TREG lymphocytes may be protective against microvascular damage, probably because of their anti-oxidant properties, while Th1-Th17 lymphocytes seem to exert an opposite effect, confirming an involvement of adaptive immune system in microvascular damage.

[Morbidity of bodylift. Evaluation of 111 patients over 5 years]

INTRODUCTION

The management of patients with weight loss sequelae, sometimes major, is increasingly well standardized. However, this surgery is not without risk. Complications of bodylift are more frequent than those of conventional abdominoplasties. The objective of this study was to evaluate the morbidity associated with this surgery through a retrospective, single-center study.

MATERIALS AND METHODS

One hundred and eleven circular abdominaloplasties were conducted between June 2011 and September 2015 in the plastic surgery department of the university hospital of Toulouse. Minor and major complications were identified and analyzed.

RESULTS

Frequency of postoperative complications was 44.1% in our series. Major complications have involved 15.3% of patients. Blood transfusions (9%) and hematoma requiring reoperation (7.2%) were the most frequent major complications. We found significantly more major complications in patients with important fat resection with a cut off at 3200 g (P=0.02). Men experienced significantly more major complications than women (P=0.005). The average delta-BMI (before and after weight loss) was significantly higher in the group of patients with the highest percentage of minor complications (P=0.045). Indeed, a high delta-BMI (greater than 19.5) was associated with an excess risk of minor complications in our population.

CONCLUSION

Democratization and progress in the field of bodylift should not obscure the fact that it is, in reality, a procedure at risk. While we manage increasingly better cosmetic results and thromboembolic complications, it still persists many complications.

Effect of antihypertensive treatment with lercanidipine on endothelial progenitor cells and inflammation in patients with mild to moderate essential hypertension

BACKGROUND

It has been demonstrated that circulating endothelial progenitor cells (EPCs) number reflects the endogenous vascular repair ability, with the EPCs pool declining in presence of cardiovascular risk factors. Several drugs, including dihydropyridine calcium channel blockers, have been reported to elicit antioxidant and anti-inflammatory properties, as well as to improve vascular remodeling and dysfunction. However, no data are available about the effects of lercanidipine on EPCs. The aim of the present study was therefore to investigate the effects of short-term treatment with lercanidipine on circulating EPCs, as well as on indices of inflammation and oxidative stress.

PATIENTS AND METHODS

Twenty essential hypertensive patients were included in the study and treated for 4 weeks with lercanidipine 20 mg per day orally. Investigations were performed in basal condition, after appropriate wash out of previous treatments, and after 4 weeks of lercanidipine treatment. Inflammatory and oxidative stress markers were assessed by ELISA technique. Lin-/7AAD-/CD34+/CD133+/VEGFR-2 + and Lin-/7AAD-/CD34+/VEGFR-2 + cells were identified by flow cytometry and considered as EPCs. EPCs cells were expressed as number of cells per million Lin-mononuclear cells.

RESULTS

Circulating EPCs were significantly increased after lercanidipine treatment (CD34+/CD133+/VEGFR-2 + cells: 78.3 ± 64.5 vs 46.6 ± 32.8; CD34+/VEGFR-2+: 87996 ± 165116 vs 1026 ± 1559, respectively, p < 0.05). A modest reduction in circulating indices of inflammation was also observed.

CONCLUSIONS

In conclusion, lercanidipine is able to increase the number of circulating EPCs, possibly through a reduction of low-grade inflammation.

Hydrogen sulfide depletion contributes to microvascular remodeling in obesity

Structural remodeling of the microvasculature occurs during obesity. Based on observations that impaired H2S signaling is associated with cardiovascular pathologies, the current study was designed to test the hypothesis that altered H2S homeostasis is involved in driving the remodeling process in a diet-induced mouse model of obesity. The structural and passive mechanical properties of mesenteric resistance arterioles isolated from 30-wk-old lean and obese mice were assessed using pressure myography, and vessel H2S levels were quantified using the H2S indicator sulfidefluor 7-AM. Remodeling gene expression was assessed using quantitative RT-PCR, and histological staining was used to quantify vessel collagen and elastin. Obesity was found to be associated with decreased vessel H2S concentration, inward hypertrophic remodeling, altered collagen-to-elastin ratio, and reduced vessel stiffness. In addition, mRNA levels of fibronectin, collagen types I and III, matrix metalloproteinases 2 and 9, and tissue inhibitor of metalloproteinase 1 were increased and elastin was decreased by obesity. Evidence that decreased H2S was responsible for the genetic changes was provided by experiments in which H2S levels were manipulated, either by inhibition of the H2S-generating enzyme cystathionine γ-lyase with dl-propargylglycine or by incubation with the H2S donor GYY4137. These data suggest that, during obesity, depletion of H2S is involved in orchestrating the genetic changes underpinning inward hypertrophic remodeling in the microvasculature.

Blockade of the renin-angiotensin system in small arteries and anticontractile function of perivascular adipose tissue

BACKGROUND/AIMS

In patients with obesity, there is increased inflammation with attendant oxidative stress in perivascular adipose tissue. This has functional consequences with loss of vasodilator adipokine bioavailability. Part of the inflammatory response is mediated by increased activation of the renin-angiotensin-aldosterone axis. Therefore, this study was designed to investigate whether angiotensin-converting enzyme inhibitors or angiotensin receptor blockers can improve the anticontractile function of perivascular adipose tissue.

METHODS

Segments of rat mesenteric small artery were dissected and mounted in a wire myograph and contracted to incremental doses of norepinephrine in the presence and absence of perivascular adipose tissue and in conditions of normal oxygenation or after hypoxia and incubated with captopril or telmisartan.

RESULTS

Vessels with perivascular adipose tissue contracted significantly less than arteries with perivascular adipose tissue removed under normal oxygenation conditions, indicating that perivascular adipose tissue exerts an anticontractile effect. Hypoxia induced a loss of this anticontractile effect which could be completely prevented with captopril or telmisartan.

CONCLUSION

The in-vitro creation of a hypoxic environment can simulate the loss of anticontractile perivascular adipose tissue function seen in vivo in obese patients, and this can be prevented using inhibitors of the renin-angiotensin cascade.

Visceral adiposopathy: a vascular perspective

Obesity has emerged as one of the most critical health care problems globally that is associated with the development of insulin resistance, type 2 diabetes mellitus, metabolic dysfunction and cardiovascular disease. Central adiposity with intra-abdominal deposition of visceral fat, in particular, has been closely linked to cardiometabolic consequences of obesity. Increasing epidemiological, clinical and experimental data suggest that both adipose tissue quantity and perturbations in its quality termed "adiposopathy" contribute to mechanisms of cardiometabolic disease. The current review discusses regional differences in adipose tissue characteristics and highlights profound abnormalities in vascular endothelial function and angiogenesis that are manifest within the visceral adipose tissue milieu of obese individuals. Clinical data demonstrate up-regulation of pro-inflammatory and pro-atherosclerotic mediators in dysfunctional adipose tissue that may support pathological vascular changes not only locally in fat but also in multiple organ systems, including coronary and peripheral circulations, potentially contributing to mechanisms of obesity-related cardiovascular disease.

Anticontractile activity of perivascular fat in obese mice and the effect of long-term treatment with melatonin

AIMS

It has been demonstrated previously that inflammation in perivascular adipose tissue (PVAT) may be implicated in vascular dysfunction. The aim of this study was to investigate the functional responses of small mesenteric arteries in a hyperphagic animal model of obesity after chronic treatment with melatonin, an endogenous hormone with antioxidant and vasculoprotective properties.

METHODS AND RESULTS

Ten obese mice (ob/ob) and 10 control lean mice (CLM) were treated with melatonin 100  mg/kg per day in the drinking water for 8 weeks. Mesenteric small resistance arteries were dissected and mounted on a wire myograph and a concentration-response to norepinephrine was evaluated in vessels with intact PVAT and after PVAT was removed and in the presence of iberiotoxin, a selective blocker of BKCA channels as well as under conditions of induced hypoxia in vitro. The presence of PVAT reduced the contractile response to norepinephrine in both ob/ob and CLM; however, the effect was significantly reduced in ob/ob. The anticontractile effect of PVAT completely disappeared with iberiotoxin preincubation. After melatonin treatment, inflammation was significantly ameliorated, and the contractile response in ob/ob and CLM was significantly reduced when PVAT was removed. Anticontractile effect of PVAT that is lost in obesity can be rescued using melatonin. A reduced expression of adiponectin and adiponectin receptor was observed in perivascular fat of ob/ob, whereas significant increase was observed in ob/ob treated with melatonin.

CONCLUSION

Melatonin seems to exert a protective effect on arteries from both ob/ob and CLM, counteracting the adverse effect of hypoxia and iberiotoxin.

Effect of antihypertensive treatment on microvascular structure, central blood pressure and oxidative stress in patients with mild essential hypertension

BACKGROUND

It has been previously demonstrated that dihydropyridine calcium channel blockers may possess antioxidant properties and might improve vascular structure. Combination treatment with an angiotensin-converting enzyme inhibitor may have additional advantages, compared with a thiazide diuretic, in this regard. The aim of the present study was, therefore, to investigate the effects of a short-term treatment with lercanidipine, and to compare two combination treatments: lercanidipine + enalapril vs. lercanidipine + hydrochlorothiazide on structural alterations in retinal arterioles, on skin capillary density and on large artery distensibility.

PATIENTS AND METHODS

Twenty essential hypertensive patients were included in the study and treated for 4 weeks with lercanidipine 20 mg per day orally. Then they were treated for 6 months with lercanidipine + enalapril (n=10) or lercanidipine + hydrochlorothiazide (n=10) combinations. Investigations were performed in basal condition, after appropriate washout of previous treatments, after 4 weeks of lercanidipine monotherapy treatment, and at the end of the combination treatment. Non-invasive measurements of wall-to-lumen ratio (W/L) and other morphological parameters of retinal arterioles using scanning laser Doppler flowmetry were performed (Heidelberg Retina Flowmeter, Heidelberg Engineering). Capillary density was evaluated by capillaroscopy, whereas pulse wave velocity and central blood pressure were assessed by the Sphygmo-Cor device (AtCor Medical West Ryde, Australia).

RESULTS

A significant improvement of W/L and of other indices of retinal artery structure was observed after treatment with lercanidipine alone, with a further improvement after treatment with lercanidipine + enalapril, whereas after treatment with lercanidipine + hydrochlorothiazide the improvement was no longer observed. A similar behaviour was observed for central SBP and DBP. Capillary density was increased only after treatment with lercanidipine + enalapril.

CONCLUSION

Lercanidipine both in monotherapy and in combination with enalapril, was able to improve microvascular structure and to decrease central blood pressure, being thus a useful approach for both reducing blood pressure and improving vascular alterations in hypertension.

[Abdominoplasty complications: particularities of the post-bariatric patients within a 238 patients series]

BACKGROUND

Obesity is one of the health issues that is recently worldwide increasing, as well as in France. Variety of procedures of bariatric surgery have been developed over the past decade and are performed for morbid obesity hence. The demand of plastic surgery increased for body contouring and reshaping after dramatic weight loss, in which the abdominoplasty is considered as one of the most common procedures. The purpose of this study is to clarify the differences between the post-bariatric patients and others, and their influence on the occurrence of complications following abdominoplasty.

PATIENTS AND METHODS

Retrospective study involving a group of post-abdominoplasty patients collected from the same center between January 2000 and December 2010.

RESULTS

Among 238 reviewed patients' files; 114 of them are post-bariatric patients, and 124 are non-bariatric patients. Several differences were found between these two groups of patients including the maximum BMI, BMI at the time of surgery, the rates of cardiovascular risk factors, and a longer operative time in the post-bariatric group. The complication rate in these patients was significantly higher (55.3% against 26.6%) with mainly healing problems. Major maximum weight, obesity at the time of surgery, long operative time and postoperative drainage system are all considered as risk factors, which carry high rate of complications.

CONCLUSION

It appears that abdominoplasty in post-bariatric patients requires specific care because of particularities inherent in this population.

Tumour necrosis factor-alpha participates on the endothelin-1/nitric oxide imbalance in small arteries from obese patients: role of perivascular adipose tissue

AIMS

We assessed the impact of vascular and perivascular tumour necrosis factor-alpha (TNF-α) on the endothelin (ET)-1/nitric oxide (NO) system and the molecular pathways involved in small arteries from visceral fat of obese patients (Obese) and Controls.

METHODS AND RESULTS

Isolated small arteries from 16 Obese and 14 Controls were evaluated on a pressurized micromyograph. Endogenous ET-1 activity was assessed by the ETA blocker BQ-123. TNF-α and NO were tested by anti-TNF-α infliximab (IFX) and N(ω)-nitro-l-arginine methylester (L-NAME). Gene and protein expression of TNF-α, ET-1, ETA, and ETB receptors were determined by RT-PCR and IHC on arterial wall and in isolated adipocytes. Obese showed a blunted L-NAME-induced vasoconstriction, which was potentiated by IFX, and an increased relaxation to BQ-123, unaffected by L-NAME but attenuated by IFX. Perivascular adipose tissue (PVAT) removal reversed these effects. Obese showed intravascular superoxide excess, which was decreased by apocynin (NAD(P)H oxidase inhibitor), L-NAME, and BQ-123 incubations, and abolished by IFX. An increased vascular expression of ET-1, ETA, and ETB receptors, and higher vascular/perivascular TNF-α and TNF-α receptor expression were also detected. The arterial expression and phosphorylation of c-Jun N-terminal kinase (JNK) were higher in Obese vs. Controls, and downregulated by IFX.

CONCLUSIONS

In small arteries of Obese, PVAT-derived TNF-α excess, and an increased vascular expression of ET-1 and ETA receptor, contribute to the ET-1/NO system imbalance, by impairing tonic NO release. Reactive oxygen species excess, via NAD(P)H oxidase activation, induces the endothelial nitric oxide synthase uncoupling, which in turn generates superoxide and impairs NO production. The up-regulated JNK pathway represents a crucial molecular signalling involved in this process.

[Complications and level of satisfaction after dermolipectomy and abdominoplasty post-bariatric surgery]

BACKGROUND

Body contouring surgery is in high demand following the increase in bariatric surgery. But these types of procedures are associated with high complication rates that cause long hospital stays and have a negative effect on patient satisfaction. The purpose of this study is to identify predictors of complications in order to optimize outcomes in these patients and find a relationship between complication rate and satisfaction.

MATERIAL AND METHODS

Out of a group of 175 post-bariatric patients, 72 patients underwent body contouring surgery following massive weight loss from 2003-2008. They were reviewed retrospectively for demographic data, pre- and postoperative weight status, co-morbidities and complications and reoperation rate. Patient satisfaction was evaluated.

RESULTS

a)

COMPLICATIONS

The overall complication rate was 45.8%. The most frequent were seromas (23.6%); infection (13.9%), bleeding (11.1%), hematoma (6.9%) (needing transfusions [6.9%]), skin necrosis (6.9%) and umbilical necrosis (4.2%). A total of 8 patients required reoperation (11.1%). b) Satisfaction rating: 1) very satisfied: 51.4%, 2) satisfied: 31.9%, 3) dissatisfied: 8.3%, 4) very dissatisfied: 8.3%. c) The presence of complications was significantly associated with patients' satisfaction, reoperation rate and longer hospital stays (P<.001).

CONCLUSIONS

Post operative complications were frequent. No predictors could be found to prevent these complications and optimize patient selection and appropriate timing of surgery. Patients with complications had a significantly higher reoperation rate, longer hospital stay and more dissatisfaction. The patients' satisfaction was negatively influenced by complication occurrence and not by the aesthetic results.

Moderate Obesity and Endothelial Dysfunction in Humans: Influence of Gender and Systemic Inflammation

Our objective was to determine whether moderate obesity (Body Mass Index [BMI] ≥ 30 kg/m²) is associated with impaired conduit and microvascular endothelial function, and whether men or women are more susceptible to impairment of endothelial function related to moderate obesity. Forty-one middle aged, nondiabetic moderately obese (BMI 34.7 ± 4.0 kg/m²) and nonobese (BMI 24.3 ± 2.6 kg/m²) subjects of both sexes underwent noninvasive studies of endothelial function (brachial reactivity) and measurements of endothelial-dependent vasodilation of gluteal subcutaneous arterioles to acetylcholine (Ach). Endothelium-dependent vasodilation to Ach was decreased in the moderately obese compared with the nonobese (P < 0.001). Stratified analysis based on sex showed impairment of arteriolar endothelial function in women BMI ≥ 30 kg/m² (P = 0.02), but not men. There was no difference between in vivo endothelial function flow-mediated dilation (FMD%) by BMI category. Sex-specific analysis showed FMD% was lower in women with BMI ≥ 30 kg/m² compared to those with BMI < 30 kg/m² (P = 0.02). No differences were seen in men based on BMI category (P = 0.18). In women, high sensitivity C-reactive protein (hsCRP) correlated with BMI (ρ = 0.68, P = 0.006). Moderate obesity is associated with impaired resistance arteriolar endothelial function. This is more prominent in women than men and is associated with systemic inflammation.

Blood pressure, ocular perfusion pressure, and body mass index in glaucoma patients

PURPOSE

To investigate relationships between blood pressure (BP), ocular perfusion pressure (OPP), and intraocular pressure (IOP) in patients with open-angle glaucoma (OAG) of different body mass index (BMI) classes. 


METHODS

Data from participants of a prospective, longitudinal, single site, observational study were analyzed. Patients with a prior diagnosis of OAG completed 2 baseline visits (1 week apart) with follow-up visits every 6 months for 2 years. At each visit, BP, weight, height, and IOP were recorded for normal-weight (BMI 18.5-24.9; n = 38), overweight (BMI 25.0-29.9; n = 43), and obese (BMI ≥30; n = 34) patients: The BP was measured using automated ambulatory measurements after 5 minutes rest and IOP was measured using Goldmann applanation tonometry.


RESULTS

The IOP decreased from baseline to 2-year measurement in normal-weight (-1.5, 95% confidence interval [CI] -2.7 to -0.4), overweight (-1.9, 95% CI -3.4 to -0.4), and obese (-2.5, 95% CI -3.9 to -1.2) patients with OAG. Systolic BP (SBP) and OPP decreased from baseline to 2-year measurement in all 3 BMI categories, although not reaching statistical significance. In normal-weight patients, there was a significant, positive correlation between changes in IOP and SBP (r = 0.36, p = 0.0431). A significant, negative correlation was observed between changes in IOP and OPP in overweight 
(r = -0.56, p = 0.0002) and obese (r = -0.38, p = 0.0499) patients.


CONCLUSIONS

This study demonstrated that in normal-weight individuals with OAG, changes in SBP were positively correlated to changes in IOP. However, this relationship did not exist for overweight or obese patients. Instead, overweight and obese patients displayed a negative correlation between OPP and IOP.

Circulating endothelial progenitor cells, microvascular density and fibrosis in obesity before and after bariatric surgery

It is not known whether, in obesity, the capillary density or the number of circulating endothelial progenitor cells (EPCs) are reduced, or whether fibrosis of small vessels is also present. In addition, possible effects of weight reduction on these parameters have never been evaluated. Therefore, we investigated EPCs and capillary density in 25 patients with severe obesity, all submitted to bariatric surgery, and in 18 normotensive lean subjects and 12 hypertensive lean patients as controls. All patients underwent a biopsy of subcutaneous fat during bariatric surgery. In five patients, a second biopsy was obtained after consistent weight loss, about 1 year later, during a surgical intervention for abdominoplasty. EPCs and capillary density were reduced in obesity, and EPCs were significantly increased after weight reduction. Vascular collagen content was clearly increased in obese patients. No significant difference in vascular collagen was observed between normotensive obese patients and hypertensive obese patients. After pronounced weight reduction, collagen content was nearly normalized. No difference in stress-strain relation was observed among groups or before and after weight loss. In conclusion, our data suggest that microvascular rarefaction occurs in obesity. EPCs were significantly reduced in obese patients. Pronounced weight loss induced by bariatric surgery seems to induce a significant improvement of EPC number, but not of capillary rarefaction. A pronounced fibrosis of subcutaneous small resistance arteries is present in obese patients, regardless of the presence of increased blood pressure values. Consistent weight loss induced by bariatric surgery may induce an almost complete regression of microvascular fibrosis.

Human skeletal muscle feed arteries: evidence of regulatory potential

AIM

Recently, it has been recognized that human skeletal muscle feed arteries can be harvested during exploratory surgery for melanoma. This approach provides vessels for in vitro study from a wide spectrum of relatively healthy humans. Although, the regulatory role of skeletal muscle feed arteries in rodent models has been documented, whether such vessels in humans possess this functionality is unknown.

METHODS

Therefore, skeletal muscle feed arteries (~950 μm OD) from 10 humans (48 ± 4, 27-64 years) were studied using pressure myography. Vessel function was assessed using potassium chloride (KCl), phenylephrine (PE), acetylcholine (ACh) and sodium nitroprusside (SNP) concentration-response curves (CRCs) to characterize non-receptor and receptor-mediated vasoconstriction as well as endothelium-dependent and independent vasodilation respectively. To understand the physiological relevance of the diameter changes as a result of pharmacological stimulation, the estimated conductance ratio (CR) was calculated.

RESULTS

Vessel function protocols revealed significant vasoconstriction in response to PE and KCl (35 ± 6; 43 ± 9%vasoconstriction, respectively) and significant vasodilation with ACh and SNP (85 ± 7; 121 ± 17% vasodilation, respectively). Both PE and KCl significantly reduced the CR (0.26 ± 0.05 and 0.23 ± 0.07, respectively), whereas ACh and SNP increased the CR (2.56 ± 0.10 and 5.32 ± 1.3, respectively).

CONCLUSION

These novel findings provide evidence that human skeletal muscle feed arteries are capable of generating significant diameter changes that would translate into significant changes in vascular conductance. Thus, human skeletal muscle feed arteries likely play a significant role in regulating vascular conductance and subsequently blood flow in vivo.

Childhood obesity: a life-long health risk

Childhood obesity has become major health concern for physicians, parents, and health agencies around the world. Childhood obesity is associated with an increased risk for other diseases not only during youth but also later in life, including diabetes, arterial hypertension, coronary artery disease, and fatty liver disease. Importantly, obesity accelerates atherosclerosis progression already in children and young adults. With regard to pathophysiological changes in the vasculature, the striking similarities between physiological changes related to aging and obesity-related abnormalities are compatible with the concept that obesity causes "premature" vascular aging. This article reviews factors underlying the accelerated vascular disease development due to obesity. It also highlights the importance of recognizing childhood obesity as a disease condition and its permissive role in aggravating the development of other diseases. The importance of childhood obesity for disease susceptibility later in life, and the need for prevention and treatment are also discussed.

Nitric oxide synthase-dependent vasodilation of human subcutaneous arterioles correlates with noninvasive measurements of endothelial function

BACKGROUND

Noninvasive measurements of endothelial function predict future adverse cardiovascular events, but offer limited opportunities for mechanistic insights into phenotypic observations. Subcutaneous adipose arterioles, accessible through minimally invasive methods, provide an opportunity for complimentary mechanistic studies. Limited data relating subcutaneous arteriolar endothelial function, cardiovascular risk factors, and noninvasive measurements of endothelial function currently exist.

METHODS

Forty-four subjects underwent noninvasive studies of endothelial function (brachial reactivity (flow-mediated dilation (FMD) and digital pulse arterial tonometry (PAT)) and measurements of endothelial-dependent vasodilation of gluteal subcutaneous arterioles to acetylcholine. Arteriolar endothelial function was measured (i) percent vasodilation to maximal acetylcholine dose (10(-5) mol/l) and (ii) total area under the curve (AUC) for the entire acetylcholine dose-response curve (total AUC-acetylcholine (Ach), doses 10(-10)-10(-5) mol/l).

RESULTS

Acetylcholine responses were almost completely nitric oxide (NO) dependent. Total AUC-Ach predicted FMD and PAT, but maximal acetylcholine vasodilation was not associated with these measures. A history of hypertension, diabetes, smoking, and low-density lipoprotein cholesterol levels were independent predictors of total AUC-Ach. In regression models, total AUC-Ach independently predicted FMD.

CONCLUSIONS

Acetylcholine vasodilator responses in human gluteal subcutaneous arterioles are NO synthase dependent and correlate with cardiac risk factors and in vivo measures of endothelial function. These data suggest subcutaneous arterioles offer an opportunity for translational studies of mechanisms of modulating NO bioavailability relevant to in vivo endothelial function measures.

Endothelial dysfunction and cardiovascular disease in early-stage chronic kidney disease: cause or association?

Chronic kidney disease (CKD) is strongly associated with cardiovascular disease (CVD); a graded inverse relationship between estimated glomerular filtration rate (eGFR) and cardiovascular event rates has emerged from large-scale observational studies. Chronic kidney disease is also associated with endothelial dysfunction (ED) although the precise relationship with GFR and the "threshold" at which ED begins are contentious. Abnormal endothelial function is certainly present in late-stage CKD but data in early-stage CKD appear confounded by disease states such as diabetes and hypertension which themselves promote ED. Thus, the direct effect of a reduction in GFR on endothelial function and, therefore, cardiovascular (CV) risk is far from completely established. In human studies, the precise duration of kidney impairment is seldom known and the onset of CVD often insidious, making it difficult to determine exactly when CVD first appears in the context of CKD. Kidney donors provide a near-ideal experimental model of CKD; subjects undergo an acute change from normal to modestly impaired renal function at the time of nephrectomy and lack the confounding co-morbidity that has made observational studies of CKD patients so challenging to interpret. By examining changes in endothelial function in living kidney donors before and after nephrectomy, useful insight might be gained into the pathophysiology of CVD in CKD and help determine whether targeting ED or the renal disease itself has the potential to reduce CV risk.

Childhood obesity: a life-long health risk

Childhood obesity has become major health concern for physicians, parents, and health agencies around the world. Childhood obesity is associated with an increased risk for other diseases not only during youth but also later in life, including diabetes, arterial hypertension, coronary artery disease, and fatty liver disease. Importantly, obesity accelerates atherosclerosis progression already in children and young adults. With regard to pathophysiological changes in the vasculature, the striking similarities between physiological changes related to aging and obesity-related abnormalities are compatible with the concept that obesity causes "premature" vascular aging. This article reviews factors underlying the accelerated vascular disease development due to obesity. It also highlights the importance of recognizing childhood obesity as a disease condition and its permissive role in aggravating the development of other diseases. The importance of childhood obesity for disease susceptibility later in life, and the need for prevention and treatment are also discussed.