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. ß 0.37) and between albuminuria and the inhibitory response of L-NAME to Ach vasodilation ( P   =  0.036, St. ß = -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.

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 p66Shc 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 p66Shc 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 p66Shc 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.

Donepezil improves vascular function in a mouse model of Alzheimer's disease.

Cardiovascular complications in Alzheimer's disease (AD) patients can occur years to decades prior to the onset of clinical symptoms of the disease. Donepezil represents the most effective drug in the treatment of AD. However, the potential effect of donepezil on vascular function and structure remains largely unexplored. Here, we assessed the impact of donepezil on the vascular phenotype of an established model of accelerated senescence that develops spontaneously AD, the SAMP8 mouse. Three groups of animals were included: SAMR1 (control strain), SAMP8, and SAMP8 treated with donepezil. Treatment with donepezil was administered from the 4th to the 6th month of life. At 6 months, after cognitive tests by Morris Water Maze, animals were euthanized, and their mesenteric arteries were processed for functional experiments. Untreated SAMP8 developed cognitive impairment compared to SAMR1, while donepezil treatment significantly attenuated cognitive dysfunction. SAMP8 exhibited a higher media-to-lumen ratio than SAMR1 and donepezil-treated animals. Endothelial function was impaired in SAMP8 animals compared to SAMR1. The addition of vitamin C improved the vasodilatory response to acetylcholine in SAMP8. Treatment with donepezil improved endothelial function in SAMP8 animals and reduced the additional vasodilation induced by vitamin C. In conclusion, in the SAMP8 AD model, cognitive impairment is associated with endothelial dysfunction and vascular remodeling which could contribute to cardiovascular events in AD since the prodromal phases of the disease. Treatment with donepezil alleviates vascular dysfunction associated with AD through an increase in NO availability likely by counteracting inflammation and oxidative stress.

Inflammation and Vascular Ageing: From Telomeres to Novel Emerging Mechanisms.

Cardiovascular disease (CVD) remains the leading cause of morbility and mortality worldwide. The identification of common cardiovascular risk factors has led to the development of effective treatments that enabled a significant reduction of the global cardiovascular disease burden. However, a significant proportion of cardiovascular risk remains unexplained by these risk factors leaving many individuals at risk of cardiovascular events despite good control of the risk factors. Recent randomized clinical trials and Mendelian randomization studies have suggested that inflammation explains a significant proportion of the residual cardiovascular risk in subjects with good control of risk factors. An accelerated process of vascular ageing is increasingly recognized as a potential mechanism by which inflammation might increase the risk of CVD. In turn, cellular ageing represents an important source of inflammation within the vascular wall, potentially creating a vicious cycle that might promote progression of atherosclerosis, independently from the individual cardiovascular risk factor burden. In this review, we summarise current evidence suggesting a role for biological ageing in CVD and how inflammation might act as a key mediator of this association.

Luteolin Prevents Cardiometabolic Alterations and Vascular Dysfunction in Mice With HFD-Induced Obesity.

Purpose: Luteolin exerts beneficial effects against obesity-associated comorbidities, although its influence on vascular dysfunction remains undetermined. We examined the effects of luteolin on endothelial dysfunction in a mouse model of diet-induced obesity. Methods: Standard diet (SD) or high-fat diet (HFD)-fed mice were treated daily with luteolin intragastrically. After 8 weeks, body and epididymal fat weight, as well as blood cholesterol, glucose, and triglycerides were evaluated. Endothelium-dependent relaxations of resistance mesenteric vessels was assessed by a concentration-response curve to acetylcholine, repeated upon Nw-nitro-L-arginine methylester (L-NAME) or ascorbic acid infusion to investigate the influence of nitric oxide (NO) availability and reactive oxygen species (ROS) on endothelial function, respectively. Intravascular ROS production and TNF levels were measured by dihydroethidium dye and ELISA, respectively. Endothelial NO synthase (eNOS) and superoxide dismutase 1 (SOD1), as well as microRNA-214-3p expression were examined by Western blot and RT-PCR assays, respectively. Results: HFD animals displayed elevated body weight, epididymal fat weight and metabolic indexes. Endothelium-dependent relaxation was resistant to L-NAME and enhanced by ascorbic acid, which restored also the inhibitory effect of L-NAME, suggesting a ROS-dependent reduction of NO availability in HFD vessels. Moreover, media-lumen ratio, intravascular superoxide anion and TNF levels were increased, while vascular eNOS, SOD1, and microRNA-214-3p expression were decreased. In HFD mice, luteolin counteracted the increase in body and epididymal fat weight, and metabolic alterations. Luteolin restored vascular endothelial NO availability, normalized the media-lumen ratio, decreased ROS and TNF levels, and normalized eNOS, SOD1 and microRNA-214-3p expression. Conclusion: Luteolin prevents systemic metabolic alterations and vascular dysfunction associated with obesity, likely through antioxidant and anti-inflammatory mechanisms.

Aging Modulates the Influence of Arginase on Endothelial Dysfunction in Obesity.

Objective- Arginase can reduce NO availability. In this study, we explored arginase as a determinant of endothelial dysfunction in small arteries from obese patients and its relationship with aging and microvascular remodeling. Approach and Results- Small arteries were dissected after subcutaneous fat biopsies and evaluated on a pressurized micromyograph. Endothelium-dependent vasodilation was assessed by acetylcholine, repeated under L-NAME ( N G-nitro-L-arginine-methyl ester), N(ω)-hydroxy-nor-l-arginine (arginase inhibitor) and gp91ds-tat (NADPH [nicotinamide adenine dinucleotide phosphate oxidase] oxidase inhibitor) in vessels from young (age <30 years) control and obese and old (>30 years) control and obese subjects. Media-lumen ratio and amount of vascular wall fibrosis were used as markers of vascular remodeling. Amount of vascular superoxide anions and NO production were determined with immunofluorescence, whereas arginase expression was quantified using Western blot and quantitative polymerase chain reaction. Obese and older age groups had lower vascular NO, as well as higher media-lumen ratio, wall fibrosis, intravascular superoxide, and blunted inhibitory effect of L-NAME on acetylcholine versus controls and younger age groups. N(ω)-hydroxy-nor-l-arginine restored the acetylcholine-induced vasodilation in young and, to a lesser extent, in old obese subjects. This effect was abolished by addition of L-NAME. Gp91ds-tat increased the vasodilatory response to N(ω)-hydroxy-nor-l-arginine in old obese. Superoxide anions and arginase I/II levels were higher in the vascular wall of obese versus controls. Conclusions- Arginase contributes to microvascular endothelial dysfunction in obesity. Its impact is reduced by aging because of higher levels of vascular oxidative stress. Obesity is accompanied by accelerated microvascular remodeling, the extent of which is related to the amount of arginase in the vascular wall.

The flavonoid compound apigenin prevents colonic inflammation and motor dysfunctions associated with high fat diet-induced obesity.

BACKGROUND AND PURPOSE: Apigenin can exert beneficial actions in the prevention of obesity. However, its putative action on obesity-associated bowel motor dysfunctions is unknown. This study examined the effects of apigenin on colonic inflammatory and motor abnormalities in a mouse model of diet-induced obesity. EXPERIMENTAL APPROACH: Male C57BL/6J mice were fed with standard diet (SD) or high-fat diet (HFD). SD or HFD mice were treated with apigenin (10 mg/Kg/day). After 8 weeks, body and epididymal fat weight, as well as cholesterol, triglycerides and glucose levels were evaluated. Malondialdehyde (MDA), IL-1ß and IL-6 levels, and let-7f expression were also examined. Colonic infiltration by eosinophils, as well as substance P (SP) and inducible nitric oxide synthase (iNOS) expressions were evaluated. Motor responses elicited under blockade of NOS and tachykininergic contractions were recorded in vitro from colonic longitudinal muscle preparations. KEY RESULTS: When compared to SD mice, HFD animals displayed increased body weight, epididymal fat weight and metabolic indexes. HFD mice showed increments in colonic MDA, IL-1ß and IL-6 levels, as well as a decrease in let-7f expression in both colonic and epididymal tissues. HFD mice displayed an increase in colonic eosinophil infiltration. Immunohistochemistry revealed an increase in SP and iNOS expression in myenteric ganglia of HFD mice. In preparations from HFD mice, electrically evoked contractions upon NOS blockade or mediated by tachykininergic stimulation were enhanced. In HFD mice, Apigenin counteracted the increase in body and epididymal fat weight, as well as the alterations of metabolic indexes. Apigenin reduced also MDA, IL-1ß and IL-6 colonic levels as well as eosinophil infiltration, SP and iNOS expression, along with a normalization of electrically evoked tachykininergic and nitrergic contractions. In addition, apigenin normalized let-7f expression in epididymal fat tissues, but not in colonic specimens. CONCLUSIONS AND IMPLICATIONS: Apigenin prevents systemic metabolic alterations, counteracts enteric inflammation and normalizes colonic dysmotility associated with obesity.

Neuroendocrine Dysregulation in Irritable Bowel Syndrome Patients: A Pilot Study.

BACKGROUND/AIMS: Irritable bowel syndrome (IBS) is a multifactorial disorder, involving dysregulation of brain-gut axis. Our aim was to evaluate the neuroendocrine activity in IBS. METHODS: Thirty IBS and 30 healthy volunteers were enrolled. Psychological symptoms were evaluated by questionnaires. Urinary 5-hydroxyindoleacetic acid, plasma serotonin (5-hydroxytryptamine, 5-HT), endothelin, and neuropeptide Y (NPY), and plasma and urinary cortisol levels were evaluated. Fourteen IBS subjects underwent microneurography to obtain multiunit recordings of efferent postganglionic muscle sympathetic nerve activity (MSNA). RESULTS: Prevalent psychological symptoms in IBS were maladjustment (60%), trait (40%) and state (17%) anxiety, obsessive compulsive-disorders (23%), and depressive symptoms (23%). IBS showed increased NPY (31.9 [43.7] vs 14.8 [18.1] pmol/L, P = 0.006), 5-HT (214.9 [182.6] vs 141.0 [45.5] pg/mL, P = 0.010), and endothelin [1.1 [1.4] vs 2.1 [8.1] pg/mL, P = 0.054], compared to healthy volunteers. Moreover, plasma NPY, endothelin, cortisol and 5-HT, and urinary 5-hydroxyindoleacetic acid were associated with some psychological disorders (P ≤ 0.05). Despite a similar resting MSNA, after cold pressor test, IBS showed a blunted increase in MSNA burst frequency (+4.1 vs +7.8 bursts/min, P = 0.048; +30.1% vs +78.1%, P = 0.023). Baseline MSNA tended to be associated with urinary cortisol (ρ = 0.557, P = 0.059). Moreover, changes in heart rate after mental stress were associated with urinary cortisol (ρ = 0.682, P = 0.021) and changes in MSNA after mental stress were associated with plasma cortisol (ρ = 0.671, P = 0.024)." CONCLUSION: Higher concentrations of endothelin, NPY, and 5-HT were found to be associated with some psychological disorders in IBS patients together with an altered cardiovascular autonomic reactivity to acute stressors compared to healthy volunteers.

Different Impact of Essential Hypertension on Structural and Functional Age-Related Vascular Changes.

We evaluated whether vascular remodeling is present in physiological aging and whether hypertension accelerates the aging process for vascular function and structure. Small arteries from 42 essential hypertensive patients (HT) and 41 normotensive individuals (NT) were dissected after subcutaneous biopsy. Endothelium-dependent vasodilation (pressurized myograph) was assessed by acetylcholine, repeated under the nitric oxide synthase inhibitor N-nitro-l-arginine methylester or the antioxidant tempol. Structure was evaluated by media-lumen ratio (M/L). Intravascular oxidative generation and collagen deposition were assessed. Inhibition by N-nitro-l-arginine methylester on ACh was inversely related to age in both groups (P<0.0001) and blunted in HT versus NT for each age range. In NT, tempol enhanced endothelial function in the oldest subgroup; in HT, the potentiating effect started earlier. HT showed an increased M/L (P<0.001) versus control. In both groups, M/L was directly related to age (P<0.0001). M/L was greater in HT, starting from 31 to 45 years range. A significant age-hypertension interaction occurred (P=0.0009). In NT, intravascular superoxide emerged in the oldest subgroup, whereas it appeared earlier among HT. Among NT, aged group displayed an increment of collagen fibers versus young group. In HT, collagen deposition was already evident in youngest, with a further enhancement in the aged group. In small arteries, ageing shows a eutrophic vascular remodeling and a reduced nitric oxide availability. Oxidative stress and fibrosis emerge in advanced age. In HT, nitric oxide availability is early reduced, but the progression rate with age is similar. Structural alterations include wide collagen deposition and intravascular reactive oxygen species, and the progression rate with age is steeper.

Cholecalciferol treatment downregulates renin-angiotensin system and improves endothelial function in essential hypertensive patients with hypovitaminosid D.

BACKGROUND: Vitamin D deficiency is related to an increased prevalence of cardiovascular disease. Renin-angiotensin-aldosterone system suppression and vascular dysfunction are considered among the main mechanisms implicated in this association. However, interventional studies demonstrating that vitamin D replacement reduces circulating renin-angiotensin-aldosterone components and improves vascular function in humans are still lacking. METHODS: Thirty-three consecutive patients with essential hypertension and hypovitaminosis D underwent therapy with cholecalciferol 50 000 IU/week orally for 8 weeks. Thirty-three hypertensive patients with normal vitamin D levels and 20 normotensive individuals were also enrolled as control groups. At baseline and at the end of the study, we evaluated plasma renin activity, circulating renin, angiotensin II, aldosterone and plasma vitamin D levels. Endothelial function [flow-mediated dilation (FMD)], carotid-femoral pulse wave velocity and augmentation index, peripheral and central blood pressure were also acquired. RESULTS: After 8-week cholecalciferol administration, all treated patients normalized plasma 25(OH)D values. Furthermore, a reduction in plasma levels of plasma renin activity (1.17 ±â€Š0.3 vs 1.51 ±â€Š0.4 ng/ml per h, P = 0.02), renin (13.4 ±â€Š1.7 vs 19.2 ±â€Š2.9 pg/ml, P < 0.001), angiotensin II (11.6 ±â€Š1.6 vs 15.8 ±â€Š2.7 pg/ml, P = 0.02) was observed at the end of the study. FMD was significantly increased after cholecalciferol treatment (4.4 ±â€Š2.6 vs 3.3 ±â€Š2.1%, P < 0.05), in the absence of changes of brachial artery diameter and endothelium-independent vasodilation. Carotid-femoral pulse wave velocity and augmentation index were not modified, as well peripheral and central blood pressure. CONCLUSION: The restoration of normal vitamin D levels after 8-week cholecalciferol treatment is able to inhibit peripheral renin-angiotensin system and improve FMD in essential hypertensive patients with hypovitaminosis D.

Saxagliptin prevents vascular remodeling and oxidative stress in db/db mice. Role of endothelial nitric oxide synthase uncoupling and cyclooxygenase.

To explore the hypothesis that DPP-IV are involved in the diabetes-induced vascular damage, we assessed the vascular effects of chronic administration of saxagliptin (Saxa) or metformin (Met) in db/db mice, a model of type 2 diabetes, evaluating vascular structure and endothelial function in mesenteric small arteries. The increases in media/lumen and media cross sectional area were prevented by Saxa. In db/db, the blunted response to acetylcholine was only marginally affected by L-NAME (NO-synthase inhibitor), improved by SC-560 (cyclooxygenase-1 inhibitor) or SQ-29548 (thromboxane receptor antagonist), and totally restored by Apocynin (NAD(P)H-oxidase inhibitor). DFU (cyclooxygenase-2 inhibitor) had no effect. Saxa improved acetylcholine-induced relaxation, which returned partially sensitive to the inhibition of L-NAME. Dihydroethidium staining revealed an increased intravascular superoxide production in db/db, attenuated by L-NAME and Saxa, and abrogated by apocynin. The dimer/monomer ratio of endothelial NOS was decreased in db/db mice and restored by Saxa. Cyclooxygenase-1 and thromboxane-A2 receptor expression, higher in db/db, was down-regulated by Saxa. Met treatment did not modify any of the abnormal vascular responses. Saxa reverses vascular hypertrophic remodeling and ameliorates NO availability in small arteries from db/db mice through the abrogation of NAD(P)H oxidase-driven eNOS uncoupling and by reducing the action of cyclooxygenase-1-derived vasoconstrictors downregulating the expression of thromboxane-prostanoid receptors.

Early treatment with hydroxychloroquine prevents the development of endothelial dysfunction in a murine model of systemic lupus erythematosus.

INTRODUCTION: Accelerated atherosclerosis is one of the major causes of morbidity in patients with systemic lupus erythematosus (SLE). Endothelial dysfunction (ED) is considered an early marker of atherosclerosis. It is a reversible alteration, thus representing an attractive target for prevention strategies against cardiovascular disease. Studies have shown that ED occurs in patients with SLE even in the absence of severe, active disease. Hydroxychloroquine (HCQ) is widely used in SLE to control disease activity, but its use is also associated with an improvement in long-term prognosis. Beyond the beneficial effect in well-established disease, our hypothesis is that treatment with HCQ might have a beneficial impact on ED prevention in SLE. The aim of this study was to assess the impact of early treatment with HCQ on ED in a murine model of SLE. METHODS: Twelve-week-old NZB/W F1 (NZ) and C57BL/6 J mice (controls) were allocated to receive HCQ or vehicle for 6, 12, or 18 weeks. Proteinuria and anti-double-stranded DNA autoantibodies were determined. ED was assessed in mesenteric arteries (pressurized myography). Nitric oxide (NO) availability and reactive oxygen species (ROS) production were evaluated. Vascular ROS production was measured with dihydroethidium (DHE) fluorescent dye. RESULTS: Starting from 18 weeks of age, NZ mice showed a progressive reduction in NO availability, which was normalized by ascorbic acid and apocynin in the up to 24-week-old group, and partly ameliorated in older animals. HCQ administration normalized the NO availability in the up to 24-week-old group, with a partial amelioration in the 30-week-old group. DHE analysis revealed a progressive increment of vascular ROS generation among NZ groups, which was prevented by apocynin. Similarly, in the NZ HCQ-treated group, vascular ROS production was abrogated. CONCLUSIONS: The ED that characterizes this mouse model of SLE is caused by the nicotinamide adenine dinucleotide phosphate oxidase-driven ROS excess. Very early treatment with HCQ is able to exert vascular protection via an antioxidant effect.

Ghrelin restores nitric oxide availability in resistance circulation of essential hypertensive patients: role of NAD(P)H oxidase.

AIMS: We assessed whether acute intra-arterial infusion of exogenous ghrelin can improve endothelial dysfunction by restoring nitric oxide (NO) availability in the forearm microcirculation of essential hypertensive patients. The effect of ghrelin on endothelial dysfunction (pressurized myograph), vascular oxidative stress generation (fluorescent dihydroethidium), and phosphorylation of p47phox (western blot), an index of NAD(P)H oxidase activation, in isolated small arteries taken from essential hypertensive patients (subcutaneous biopsy) were also investigated. METHODS AND RESULTS: In 18 normotensive control subjects and 18 essential hypertensive patients, we studied the forearm blood flow (strain-gauge plethysmography) response to intra-arterial acetylcholine, repeated under NO synthase inhibitor N(G)-monomethyl-l-arginine (l-NMMA) or the antioxidant ascorbic acid. The protocol was repeated at the end of exogenous ghrelin intra-arterial infusion. In hypertensive patients, ghrelin normalized the blunted response to acetylcholine, restored the inhibiting effect of l-NMMA and abrogated the potentiating effect of ascorbic acid on acetylcholine. In controls, ghrelin failed to modify these vascular responses. In hypertensive patients, ghrelin decreased venous levels of malondialdehyde, lipoperoxide, and interleukin-6, and concomitantly increased endogenous antioxidant capacity. Small vessels from hypertensive patients showed an enhanced intravascular oxidative stress, which was strongly and similarly decreased by incubation with ghrelin, the NAD(P)H oxidase inhibitor gp91 ds-tat, or both. Ghrelin also normalized the overexpression of p47 phosphorylation and restored the NO availability in small vessels from hypertensive patients. CONCLUSIONS: Exogenous ghrelin increases endothelial dysfunction by restoring NO availability in the forearm microcirculation of essential hypertensive patients, an effect ascribable to an antioxidant effect via inhibition of NAD(P)H oxidase activation.

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.

Cholecalciferol administration blunts the systemic renin-angiotensin system in essential hypertensives with hypovitaminosis D.

INTRODUCTION: Vitamin D plasma levels are negatively associated with blood pressure and cardiovascular mortality, and vitamin D supplementation reduces cardiovascular events. Renin-angiotensin system (RAS) suppression may be one of the mechanisms involved. However, there are no interventional prospective studies demonstrating a reduction in circulating RAS components after vitamin D treatment. METHODS: Fifteen consecutive drug-free patients with essential hypertension and hypovitaminosis D underwent therapy with an oral dose of 25000 I.U. of cholecalciferol once a week for two months, while maintaining a constant-salt diet. In basal conditions and at the end of the study, RAS activity (plasma angiotensinogen, renin, PRA, angiotensin II, aldosterone and urinary angiotensinogen) was investigated, in addition to blood pressure and plasma vitamin D levels (25(OH)D). RESULTS: After cholecalciferol administration, all patients exhibited normalized plasma 25(OH)D values. At the end of the study, a reduction (p < 0.05) in plasma renin and aldosterone, and a decrement, although not significant, of PRA and angiotensin II, was observed. No difference was found in plasma and urinary angiotensinogen or blood pressure values. CONCLUSIONS: Our data indicate that in essential hypertensives with hypovitaminosis D, pharmacological correction of vitamin D levels can blunt systemic RAS activity.

P2X7 receptor polymorphisms do not influence endothelial function and vascular tone in neo-diagnosed, treatment-naive essential hypertensive patients.

OBJECTIVE: Endothelial dysfunction and arterial stiffness are early vascular alterations, linked to oxidative stress and inflammation, with prognostic significance in essential hypertensive patients. P2X7 receptors (P2X7R), responding to extracellular ATP, are encoded by a highly polymorphic gene and modulate inflammatory responses and cell growth, potentially playing a role in the control of vascular tone. This study evaluated the effects of P2X7R gene polymorphisms (single nucleotide polymorphisms, SNPs) on a detailed vascular hypertensive phenotype. METHODS: We determined by real-time PCR two SNPs of the P2X7R gene (489C>T and 1513A>C) in 134 newly diagnosed, treatment-naive essential hypertensive patients and 131 normotensive controls (CTL). Endothelium-dependent response was assessed as flow-mediated dilatation (FMD) of the brachial artery, arterial stiffness as aortic pulse wave velocity (PWV) and augmentation index (AIx) by tonometry. Markers of oxidative stress were also measured. RESULTS: FMD was lower (P < 0.05), whereas aortic PWV and AIx were higher (P < 0.01) in essential hypertensive patients than in CTL. The allelic distribution of the two P2X7R SNPs was similar in essential hypertensive patients and CTL, either concerning homozygosis or presence of the mutant alleles. No difference was observed for FMD, aortic PWV, AIx or markers of oxidative stress between carriers and noncarriers of the mutant alleles, either in essential hypertensive patients and in CTL. In the whole group, logistic regression showed that the mutant allele of 1513A>C was a main determinant of AIx (odds ratio 1.90; P = 0.03). CONCLUSION: P2X7R 489C>T and 1513A>C SNPs are not associated with altered endothelial function or arterial stiffness in untreated newly diagnosed essential hypertensive patients; a possible role in influencing peripheral wave reflection should be further addressed.

Renal vasodilating capacity and endothelial function are impaired in patients with obstructive sleep apnea syndrome and no traditional cardiovascular risk factors.

OBJECTIVE: Patients with obstructive sleep apnea syndrome exhibit accelerated vascular aging and renal damage. Aim of the study was to investigate whether vascular dysfunction is a feature of obstructive sleep apnea syndrome per se or instead related to the presence of traditional cardiovascular risk factors. METHODS: Forty patients with moderate-severe obstructive sleep apnea syndrome (20 with, 20 without traditional risk factors) and 20 matched healthy controls were enrolled. Renal vasodilating capacity, endothelium-dependent vasodilation in the brachial artery, carotid-femoral pulse wave velocity and carotid stiffness were measured. Oxidative stress, endothelial biomarkers and leukocyte adhesion molecule levels were also evaluated. RESULTS: Apneic patients without traditional cardiovascular risk factors presented reduced endothelium-dependent vasodilation (3.7±2.1 versus 6.1±3.0%, P<0.05), increased serum E-selectin (49.8±11.5 versus 38.9±17.9 ng/ml, P<0.05), and impaired renal vasodilating capacity (6.0±4.3 versus 10.4±6.1%, P<0.05), as compared to healthy controls. Endothelial NO synthase expression was reduced (0.0133 versus 0.0221×10 copies/µg RNA, P<0.05), whereas oxidative stress parameters and leukocyte adhesion molecules were similar to controls. Patients with obstructive sleep apnea syndrome and traditional risk factors also exhibit increased aortic and carotid stiffness, increased renal resistive index and intima-media thickness, and reduced expression of the endothelial progenitor cell marker CD34: however, these parameters were similar to those of healthy controls in patients with isolated obstructive sleep apnea syndrome. CONCLUSION: Obstructive sleep apnea syndrome is characterized by endothelial dysfunction and activation and impaired renal vasodilating capacity even in the absence of traditional cardiovascular risk factors, possibly due to reduced endothelial NO synthase expression.

Endothelial dysfunction in small arteries of essential hypertensive patients: role of cyclooxygenase-2 in oxidative stress generation.

Essential hypertensive patients show a reduced nitric oxide availability secondary to oxidative stress generation in peripheral microcirculation. Cyclooxygenase (COX) contributes to reduce nitric oxide availability. We assessed the possible vascular sources of oxidative stress, including COX-1, COX-2, and nicotinamide adenine dinucleotide phosphate oxidase, as determinants of endothelial dysfunction in small arteries isolated from essential hypertensive patients or normotensive controls. Small arteries were dissected after subcutaneous fat biopsies and evaluated on a pressurized micromyograph. Endothelium-dependent vasodilation was assessed by acetylcholine, repeated under NG-nitro-l-arginine methyl ester, SC-560 (COX-1 inhibitor), DuP-697 (COX-2 inhibitor), ascorbic acid, or the nicotinamide adenine dinucleotide phosphate oxidase inhibitors apocynin or diphenylene iodonium. Vascular oxidative stress generation (fluorescent dihydroethidium), COX-1 and COX-2 expression (Western blot), and localization (immunohistochemistry) were also assessed. In controls, response to acetylcholine was blunted by NG-nitro-l-arginine methyl ester (P<0.001) and unmodified by SC-560, DuP-697, or ascorbic acid. In hypertensive patients, relaxation to acetylcholine was blunted, resistant to NG-nitro-l-arginine methyl ester or SC-560, and enhanced (P<0.01) by DuP-697, apocynin, or diphenylene iodonium (P<0.05). Furthermore, in hypertensive patients, response to acetylcholine was normalized by ascorbic acid or apocynin+DuP-697. Intravascular oxidative stress generation was enhanced in hypertensive patients, decreased (P<0.01) by DuP-697, partly attenuated by apocynin or diphenylene iodonium, and prevented by ascorbic acid. Enhanced COX-2 expression and localization in the vascular media of hypertensive patients were also detected. In small resistance arteries of essential hypertensive patients, COX-2 is overexpressed and reduces nitric oxide availability. COX-2 represents a major source of oxidative stress generation, whereas nicotinamide adenine dinucleotide phosphate oxidase plays a minor, but significant, role in promoting superoxide generation.

Vascular dysfunction in a mouse model of Rett syndrome and effects of curcumin treatment.

Mutations in the coding sequence of the X-linked gene MeCP2 (Methyl CpG-binding protein) are present in around 80% of patients with Rett Syndrome, a common cause of intellectual disability in female and to date without any effective pharmacological treatment. A relevant, and so far unexplored feature of RTT patients, is a marked reduction in peripheral circulation. To investigate the relationship between loss of MeCP2 and this clinical aspect, we used the MeCP2 null mouse model B6.129SF1-MeCP2tm1Jae for functional and pharmacological studies. Functional experiments were performed on isolated resistance mesenteric vessels, mounted on a pressurized myograph. Vessels from female MeCP2(+/-) mice show a reduced endothelium-dependent relaxation, due to a reduced Nitric Oxide (NO) availability secondary to an increased Reactive Oxygen Species (ROS) generation. Such functional aspects are associated with an intravascular increase in superoxide anion production, and a decreased vascular eNOS expression. These alterations are reversed by curcumin administration (5% (w/w) dietary curcumin for 21 days), which restores endothelial NO availability, decreases intravascular ROS production and normalizes vascular eNOS gene expression. In conclusion our findings highlight alterations in the vascular/endothelial system in the absence of a correct function of MeCP2, and uncover related cellular/molecular mechanisms that are rescued by an anti-oxidant treatment.