Prognostic significance of the wall to lumen ratio of retinal arterioles evaluated by adaptive optics.

OBJECTIVE: Microvascular structural alterations may be considered an important form of hypertension-mediated organ damage. An increased media-to-lumen ratio of subcutaneous small arteries evaluated with locally invasive techniques (micromyography) predicts the development of cardiovascular (CV) events. However, it is not known whether retinal arteriole structural alterations evaluated with a noninvasive approach (Adaptive Optics) may have a prognostic significance. DESIGN AND METHODS: Two-hundred and thirty-seven subjects (mean age 58.7 ± 16.1 years, age range 13-89 years; 116 males) were included in the study: 65 normotensive subjects (27.4 %) and 172 patients with essential hypertension or primary aldosteronism (72.6 %). All subjects underwent a non-invasive evaluation of retinal arteriolar wall-to-lumen ratio (WLR) by Adaptive Optics. Subjects were re-evaluated after an average follow-up time of 4.55 years in order to assess the occurrence of clinical events (non CV and/or CV death or events). RESULTS: Fifty-four events occurred in the study population:26 were cardio-cerebrovascular events (ischemic or hemorragic stroke, atrial fibrillation, heart failure, coronary artery disease, peripheral artery disease, cardiac valvular disease) while the remaining were deaths for any cause, or neoplastic diseases. Subjects with events were older and had a WLR of retinal arterioles significantly greater than those without events. The event-free survival was significantly worse in those with a baseline WLR above the median value of the population (0.28) according to Kaplan-Mayer survival curves and multivariate analysis (Cox's proportional hazard model). The evidence was confirmed after restricting the analysis to CV events. CONCLUSIONS: Structural alterations of retinal arterioles evaluated by Adaptive Optics may predict total and CV events.

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.

Changes in extracellular matrix in subcutaneous small resistance arteries of patients with essential hypertension.

BACKGROUND: In the development of hypertensive microvascular remodeling, a relevant role may be played by changes in extracellular matrix proteins. Aim of this study was the to evaluate some extracellular matrix components within the tunica media of subcutaneous small arteries in 9 normotensive subjects and 12 essential hypertensive patients, submitted to a biopsy of subcutaneous fat from the gluteal or the anterior abdominal region. PATIENTS AND METHODS: Subcutaneous small resistance arteries were dissected and mounted on an isometric myograph, and the tunica media to internal lumen ratio was measured. In addition, fibronectin, laminin, transforming growth factor-beta-1 (TGF-ß1) and emilin-1 contents within the tunica media were evaluated by immunofluorescence and relative immunomorphometrical analysis (immunopositivity % of area). The total collagen content and collagen subtypes within the tunica media were evaluated using both Sirius red staining (under polarized light) and immunofluorescence assay. RESULTS: Normotensive controls had less total and type III collagen in respect with hypertensive patients. Fibronectin and TGF-ß1 tunica media content was significantly greater in essential hypertensive patients, compared with normotensive controls, while laminin and emilin-1 tunica media content was lesser in essential hypertensive patients, compared with normotensive controls. A significant correlation was observed between fibronectin tunica media content and media to lumen ratio. CONCLUSIONS: Our results indicate that, in small resistance arteries of patients with essential hypertension, a relevant fibrosis may be detected; fibronectin and TGF-ß1 tunica media content is increased, while laminin and emilin-1 content is decreased; these changes might be involved in the development of small resistance artery remodeling in humans.

Comparison between invasive and noninvasive techniques of evaluation of microvascular structural alterations.

BACKGROUND: The evaluation of the morphological characteristics of small resistance arteries in humans is challenging. The gold standard method is generally considered to be the measurement by wire or pressure micromyography of the media-to-lumen ratio of subcutaneous small vessels obtained by local biopsies. However, noninvasive techniques for the evaluation of retinal arterioles were recently proposed; in particular, two approaches, scanning laser Doppler flowmetry (SLDF) and adaptive optics, seem to provide useful information; both of them provide an estimation of the wall-to-lumen ratio (WLR) of retinal arterioles. Moreover, a noninvasive measurement of basal and total capillary density may be obtained by videomicroscopy/capillaroscopy. No direct comparison of these three noninvasive techniques in the same population was previously performed; in particular, adaptive optics was never validated against micromyography. METHODS: In the current study, we enrolled 41 controls and patients: 12 normotensive lean controls, 12 essential hypertensive lean patients, nine normotensive obese patients and eight hypertensive obese patients undergoing elective surgery. All patients underwent a biopsy of subcutaneous fat during surgery. Subcutaneous small resistance artery structure was assessed by wire micromyography and the media-to-lumen ratio was calculated. WLR of retinal arterioles was obtained by SLDF and adaptive optics. Functional (basal) and structural (total) microvascular density was evaluated by capillaroscopy before and after venous congestion. RESULTS AND CONCLUSION: Our data suggest that adaptive optics has a substantial advantage over SLDF in terms of evaluation of microvascular morphology, as WLR measured with adaptive optics is more closely correlated with the M/L of subcutaneous small arteries (r = 0.84, P < 0.001 vs. r = 0.52, P < 0.05, slopes of the relations: P < 0.01 adaptive optics vs. SLDF). In addition, the reproducibility of the evaluation of the WLR with adaptive optics is far better, as compared with SLDF, as intraobserver and interobserver variation coefficients are clearly smaller. This may be important in terms of clinical evaluation of microvascular morphology in a clinical setting, as micromyography has substantial limitations in its clinical application due to the local invasiveness of the procedure.

Use of Antihypertensive Drugs in Neoplastic Patients.

The introduction of Vascular Endothelial Growth Factor (VEGF) signaling pathway inhibitor treatment has highlighted the role of the baseline activity of the VEFG system for blood pressure regulation. VEGF signaling pathway is associated with hypertension and proteinuria. Activation of the endothelin system, endothelial dysfunction and capillary rarefaction are among the underlying mechanisms possibly explaining the rise in blood pressure and, to some extent, also the renal injury. The hypertension induced by VEGF signaling pathway inhibition is, usually, responsive to treatment. Recommendations about the management of cardiovascular toxicity in patients receiving VEGF signaling pathway inhibitors include a formal cardiovascular risk assessment before initiation of VEGF signaling pathway inhibitor treatment, active monitoring of blood pressure and cardiac toxicity throughout treatment, with more frequent monitoring during the first cycles of therapy, given that marked and unpredictable blood pressure rises can occur early after treatment with a VEGF signaling pathway inhibitor, and aggressive management of blood pressure elevations and early symptoms and signs of cardiac toxicity to prevent clinically limiting complications. In patients with preexisting hypertension, the blood pressure target for initiating VEGF signaling pathway inhibitor treatment should be <140/90 mmHg. Blockers of the renin-angiotensin system and calcium channel antagonists are among the drugs to be preferably used in these clinical conditions.

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.

Relationship Between Different Subpopulations of Circulating CD4+ T-lymphocytes and Microvascular Structural Alterations in Humans.

BACKGROUND: 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. In addition, it was demonstrated in animal models that TREGs may prevent angiotensin II-induced hypertension and vascular injury/inflammation. However, no data are presently available in humans about possible relationships between T-lymphocyte subtypes and microvascular structural alterations. METHODS: For this purpose, 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. Subcutaneous small resistance arteries were dissected and mounted on a wire myograph and the media to lumen ratio (M/L) was calculated. In addition, retinal arteriolar structure was evaluated noninvasively by scanning laser Doppler flowmetry. Capillary density in the nailfold, dorsum of the finger, and forearm were evaluated by videomicroscopy. A peripheral blood sample was obtained before surgery for assessment of T-lymphocyte subpopulations by flow cytometry. RESULTS: Significant negative correlations were observed between indices of microvascular structure (M/L of subcutaneous small arteries and wall to lumen ratio of retinal arterioles) and circulating TREG lymphocytes. A direct correlation was observed between M/L of subcutaneous small arteries and circulating Th17 lymphocytes. In addition, total capillary density was correlated with a TREG effector memory subpopulation. CONCLUSION: Our data suggest that some lymphocyte subpopulations may be related to microvascular remodeling, confirming previous animal data, and opening therapeutic possibilities.

Cerebral small-resistance artery structure and cerebral blood flow in normotensive subjects and hypertensive patients.

INTRODUCTION: The aim of this study was to prospectively investigate whether the structure of cerebral small-resistance arteries is related to cerebral perfusion parameters as measured with dynamic susceptibility-weighted contrast magnetic resonance imaging (DSC-MRI) in a selected cohort of hypertensive and normotensive patients. METHODS: Ten hypertensive and 10 normotensive patients were included in the study. All patients underwent neurosurgical intervention for an intracranial tumor and were investigated with DSC-MRI at 1.5 T. Cerebral small-resistance arteries were dissected from a small portion of morphologically normal cerebral tissue and mounted on an isometric myograph for the measurement of the media-to-lumen (M/L) ratio. A quantitative assessment of cerebral blood flow (CBF) and volume (CBV) was performed with a region-of-interest approach. Correlation coefficients were calculated for normally distributed variables. The institutional review board approved the study, and informed consent was obtained from all patients. RESULTS: Compared with normotensive subjects, hypertensive patients had significantly lower regional CBF (mL/100 g/min) in the cortical grey matter (55.63 ± 1.90 vs 58.37 ± 2.19, p < 0.05), basal ganglia (53.34 ± 4.39 vs 58.22. ± 4.33, p < 0.05), thalami (50.65 ± 3.23 vs 57.56 ± 4.45, p < 0.01), subcortical white matter (19.32 ± 2.54 vs 22.24 ± 1.9, p < 0.05), greater M/L ratio (0.099 ± 0.013 vs 0.085 ± 0.012, p < 0.05), and lower microvessel density (1.66 ± 0.67 vs 2.52 ± 1.28, p < 0.05). A statistically significant negative correlation was observed between M/L ratio of cerebral arteries and CBF in the cortical grey matter (r = -0.516, p < 0.05), basal ganglia (r = -0.521, p < 0.05), thalami (r = -0.527 p < 0.05), and subcortical white matter (r = -0.612, p < 0.01). CONCLUSION: Our results indicate that microvascular structure might play a role in controlling CBF, with possible clinical consequences.

Effects of a long-term treatment with aliskiren or ramipril on structural alterations of subcutaneous small-resistance arteries of diabetic hypertensive patients.

Structural alterations of subcutaneous small-resistance arteries are associated with a worse clinical prognosis in hypertension and non-insulin-dependent diabetes mellitus. The effects of the direct renin inhibitor aliskiren on microvascular structure were never previously evaluated. Therefore, we investigated the effects of aliskiren in comparison with those of an extensively used angiotensin-converting enzyme inhibitor, ramipril, on peripheral subcutaneous small-resistance artery morphology, retinal arteriolar structure, and capillary density in a population of patients with non-insulin-dependent diabetes mellitus. Sixteen patients with mild essential hypertension and with a previous diagnosis of non-insulin-dependent diabetes mellitus were included in the study. Patients were then randomized to 1 of the 2 active treatments (aliskiren 150 mg once daily, n=9; or ramipril 5 mg once daily, n=7). Each patient underwent a biopsy of the subcutaneous fat from the gluteal region, an evaluation of retinal artery morphology (scanning laser Doppler flowmetry), and capillary density (capillaroscopy), at baseline and after 1 year of treatment. Subcutaneous small arteries were dissected and mounted on a pressurized micromyograph, and the media-to-lumen ratio was evaluated. A similar office blood pressure-lowering effect and a similar reduction of the wall-to-lumen ratio of retinal arterioles were observed with the 2 drugs. Aliskiren significantly reduced media-to-lumen ratio of subcutaneous small-resistance arteries, whereas ramipril-induced reduction of media to lumen ratio was not statistically significant. No relevant effect on capillary density was observed. In conclusion, treatment with aliskiren or ramipril was associated with a correction of microvascular structural alterations in patients with non-insulin-dependent diabetes mellitus.

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.

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.

Relationship between media-to-lumen ratio of subcutaneous small arteries and wall-to-lumen ratio of retinal arterioles evaluated noninvasively by scanning laser Doppler flowmetry.

BACKGROUND: Structural alterations of subcutaneous small resistance arteries, as indicated by an increased media-to-lumen ratio, are frequently present in hypertensive and/or diabetic patients, and may represent the earliest alteration observed. Furthermore, media-to-lumen ratio of small arteries evaluated by micromyography has a strong prognostic significance; however, its extensive evaluation is limited by the invasivity of the assessment, since a biopsy of subcutaneous fat is needed. Noninvasive measurement of wall-to-lumen of retinal arterioles using scanning laser Doppler flowmetry (SLDF) has recently been introduced. However, this new technique has not yet been compared to micromyographic measurement, generally considered the gold standard approach. METHODS AND RESULTS: We investigated 40 individuals and patients, 24 of them were hypertensive patients and 16 normotensive individuals. All patients underwent a biopsy of subcutaneous fat during an elective surgical intervention. Subcutaneous small resistance arteries were dissected and mounted on a wire myograph, and media-to-lumen ratio was measured. In addition, an evaluation of wall-to-lumen ratio of retinal arterioles by SLDF was performed (Heidelberg Retina Flowmeter, Heidelberg Engineering). A close correlation was observed between media-to-lumen ratio of subcutaneous small arteries and wall-to-lumen ratio of retinal arterioles (r = 0.76, P < 0.001; P < 0.001, r(2) = 0.57). CONCLUSION: A noninvasive and easily repeatable procedure (intraobserver and interobserver variation coefficient <13%) such as an evaluation of the arterioles in the fundus oculi by SLDF may provide similar information regarding microvascular morphology compared with an invasive, accurate and prognostically relevant micromyographic measurement of media-to-lumen ratio of subcutaneous small arteries.

Effects of weight loss on structural and functional alterations of subcutaneous small arteries in obese patients.

Structural alterations of subcutaneous small resistance arteries, as indicated by an increased media:lumen ratio, are frequently present in hypertensive and/or diabetic patients and may represent the earliest alteration observed. In addition, media:lumen ratios of small arteries have a strong prognostic significance. However, no data are available about the structure of small resistance arteries of obese patients, particularly after weight loss. We have investigated 27 patients with severe obesity. Twelve of them were normotensive, and 15 were hypertensive. All of the obese patients underwent bariatric surgery. We compared results obtained with those observed in 13 normotensive lean controls and in 13 hypertensive lean patients. All of the subjects and patients underwent a biopsy of subcutaneous fat during surgical intervention. In 8 obese patients, a second biopsy was obtained after consistent weight loss, during a surgical intervention for abdominoplasty. Subcutaneous small resistance arteries were dissected and mounted on a wire myograph, and structural parameters were measured. A concentration-response curve to acetylcholine was performed to evaluate endothelial function. Obese patients, independent from the presence of hypertension, show the presence of an increased media:lumen ratio and media cross-sectional area, together with an impaired endothelial-dependent vasodilatation. After surgical correction of obesity and consistent weight loss, a significant improvement of microvascular structure and of some oxidative stress/inflammation markers were observed. In conclusion, our data suggest that the presence of obesity is associated with structural alterations of subcutaneous small resistance arteries, mainly characterized by hypertrophic remodeling. Weight loss may improve microvascular structure.

How to assess microvascular structure in humans.

Structural alterations of subcutaneous small resistance arteries, as indicated by an increased media to lumen ratio, are frequently present in hypertensive and/or diabetic patients. However, the evaluation of microvascular structure is not an easy task. Among the methods that may be applied to humans, plethysmographic evaluation of small arteries and wire or pressure micromyography were extensively used in the last decades. Media to lumen ratio of small arteries evaluated by micromyography was demonstrated to possess a strong prognostic significance; however, its extensive evaluation is limited by the invasiveness of the assessment, since a biopsy of subcutaneous fat is needed. Non-invasive approaches were then proposed, including capillaroscopy, which provides information about microvascular rarefaction. Recently, the interest of investigators has focused on the retinal microvascular bed. In particular, a non-invasive measurement of wall thickness to internal lumen ratio of retinal arterioles using scanning laser Doppler flowmetry has been recently introduced. Preliminary data suggest a fairly good agreement between this approach and micromyographic measurements, generally considered the gold standard approach. Therefore, the evaluation of microvascular structure is progressively moving from bench to bedside, and it could represent, in the immediate future, an evaluation to be performed in all hypertensive patients, in order to obtain a better stratification of cardiovascular risk.

Structural alterations in subcutaneous small resistance arteries predict changes in the renal function of hypertensive patients.

BACKGROUND: We have previously demonstrated that structural alterations in subcutaneous small resistance arteries of hypertensive patients, as indicated by an increased media to lumen ratio (M/L), are a potent predictor of cardiovascular events, and that a close correlation exists between serum creatinine and M/L. The aim of the present study was to assess whether M/L of subcutaneous small resistance arteries may predict subsequent changes in renal function in hypertensive patients. METHOD: Sixty participants (13 normotensive participants and 47 hypertensive patients) underwent a biopsy of subcutaneous fat. Resistance-sized arteries were dissected and mounted on a wire myograph, and M/L was measured. Patients were re-evaluated after a mean follow-up period of 8.6 years. Serum creatinine, blood urea nitrogen, and uric acid were measured; glomerular filtration rate (eGFR) was estimated according to Modification of Diet in Renal Disease formula. RESULTS: At baseline, we observed significant correlations between M/L and serum creatinine, eGFR, blood urea nitrogen, systolic, diastolic, mean, and pulse pressure. In addition, we observed significant correlations between M/L and serum creatinine at follow-up (r = 0.57; P < 0.001), percentage changes in serum creatinine (r = 0.46; P < 0.001), eGFR at follow-up (r = -0.43; P < 0.001); percentage changes in eGFR, yearly changes in eGFR, blood urea nitrogen at follow-up, and uric acid at follow-up. A multivariate analysis in which all common cardiovascular risk factors were included showed that M/L ratio is the most potent predictor of changes in renal function. CONCLUSION: Our data suggest that structural alterations in subcutaneous small arteries may predict the time course of changes in renal function during a follow-up period of about 9 years.

Vasodilator effects of red wines in subcutaneous small resistance artery of patients with essential hypertension.

BACKGROUND: It has been suggested that in animal models, red wine may have a protective effect on the vascular endothelium. However, it is not known whether this effect is also present in human small vessels and whether it is specific for certain wines. The objective of this study is to compare the vasodilator effects in subcutaneous small resistance arteries of wines with different flavonoid content as well as of ethanol vs. wines in normotensive (NT) subjects and in patients with essential hypertension (EH). METHODS: Twenty-six EH and 27 NT were included in the study. Subcutaneous small resistance arteries were dissected and mounted on a micromyograph. Then we evaluated vasodilator responses as concentration-response curves (20, 30, and 50 microl) to the following items: (i) a red wine produced in small oak barrels ("en barrique": EB) (Barolo Oberto 1994), (ii) a red wine produced in large wood barrels (LB) (Barolo Scarzello 1989), (iii) a red wine produced in steel tanks (Albarello Rosso del Salento 1997), and (iv) a white wine produced in steel tanks in the presence or absence of an inhibitor of the nitric oxide (NO) synthase (L-NMMA 100 micromol/l). RESULTS: A dose-dependent vasodilator effect of red wines (particularly EB and LB) was detected in both NT and HT. The observed response was not reduced after preincubation with L-NMMA. CONCLUSIONS: Our results suggest red wines are more potent vasodilator than ethanol alone, possibly depending on the content of polyphenols or tannic acid. HT show similar responses compared with NT, indicating that red wine is not harmful in this population.

Altered structure of small cerebral arteries in patients with essential hypertension.

OBJECTIVE: Structural alterations in the microcirculation may be considered an important mechanism of organ damage. An increased media-to-lumen ratio of subcutaneous small resistance arteries has been demonstrated to predict the development of cardiocerebrovascular events in hypertensive patients. Alterations in the structure of small cerebral arteries have been demonstrated in animal models of experimental or genetic hypertension. However, no evaluation with reliable techniques has ever been performed in humans. DESIGN AND METHODS: Twenty-eight participants were included in the present study: they were 13 hypertensive patients and 15 normotensive individuals. All participants underwent a neurosurgical intervention for benign or malign tumors. A small portion of morphologically normal cerebral tissue was excised from surgical samples and examined. Cerebral small resistance arteries (relaxed diameter around 200 mum) were dissected and mounted on an isometric and isobaric myograph, and the tunica media to internal lumen ratio was measured. In addition, cerebral cortical microvessel density (MVD) was also evaluated. The tissue was sectioned and stained for CD31, and MVD was measured with an automated image analyzer (percentage of area stained). Blood pressure values were evaluated, before surgical intervention, by standard sphygmomanometry. RESULTS: M/L was significantly greater and MVD significantly lower in hypertensive patients than that in normotensive individuals. No difference between groups in collagen content or mechanical properties of cerebral small arteries was observed. CONCLUSION: Our results indicate that structural alterations of small cerebral vessels are present in hypertensive patients compared with normotensive individuals, similar to those previously observed in subcutaneous small arteries.

Determinants of the structure of resistance-sized arteries in hypertensive patients.

OBJECTIVE: It has been previously demonstrated that structural alterations of subcutaneous small resistance arteries of hypertensive patients, as indicated by an increased media to lumen (M/L) ratio, is the most potent predictor of cardiovascular events. The aim of the present study was to identify possible determinants of small resistance artery structure that may be evaluated with non-invasive approaches. MATERIALS AND METHODS: One hundred and ninety-nine subjects (normotensives, essential hypertensives and patients with secondary hypertension) were included in the present study. All subjects were submitted to a biopsy of subcutaneous fat from the gluteal or the anterior abdominal region. Small resistance arteries were dissected and mounted on an isometric myograph, and M/L ratio was measured. All patients underwent standard biochemical tests, clinic blood pressure measurement, standard echocardiography and 24-h ambulatory blood pressure measurement. Glomerular filtration rate (GFR) was calculated according to MDRD study formula and Cockroft's formula. RESULTS: Significant correlation was found between M/L ratio and, respectively: GFR calculated both with MDRD study formula and Cockroft-Gault formula, creatinine serum, blood urea nitrogen, glycaemia, circulating sodium, clinical pulse pressure, stroke volume to pulse pressure ratio, clinical systolic, diastolic and mean arterial pressure, daytime pulse pressure. However, in a multivariate regression analysis, only serum creatinine remained in the model, and proved to be an independent predictor of small artery structure. CONCLUSIONS: Indices of renal function and, probably, of large artery distensibility may be related to small arteries remodelling in hypertension.

Prognostic role of flow-mediated dilatation of the brachial artery in hypertensive patients.

BACKGROUND: The prognostic role of endothelial dysfunction, as evaluated by flow-mediated vasodilatation of the brachial artery, has been demonstrated in patients at very high risk. We aimed to investigate whether flow-mediated vasodilatation predicts cardiovascular events in uncomplicated hypertensive patients. METHODS AND RESULTS: A total of 172 prospectively identified uncomplicated hypertensive patients (age 56 +/- 8 years, 41% women, 48 with diabetes mellitus type 2) were studied. At baseline all patients were untreated and underwent baseline standard laboratory examination. A standard echocardiogram was performed for the evaluation of left ventricular anatomy and function and patients with systolic dysfunction or left ventricular wall motion abnormalities were excluded. Endothelial function was measured as flow-mediated vasodilatation of the brachial artery using high-resolution ultrasound. Patients were followed for 95 +/- 37 months (range 2-136 months). A first nonfatal or fatal cardiovascular event occurred in 32 patients. The incidence of cardiovascular events was 1.4 and 3.1 per 100 patient-years in patients with a flow-mediated vasodilatation below and above the median value (4.7%), respectively (P < 0.005 by the log-rank test). In Cox analysis, controlling for age, sex, glycemia, cholesterol, smoking, BMI, systolic and diastolic blood pressure at baseline and left ventricular mass index, a low flow-mediated vasodilatation conferred an increased risk of cardiovascular events (odds ratio 2.67, 95% confidence interval 1.17 to 6.1, P = 0.02). CONCLUSION: The presence of endothelial dysfunction, as evaluated by flow-mediated vasodilatation of the brachial artery, identifies hypertensive patients at increased risk of nonfatal and fatal cardiovascular events.