Effect of antihypertensive treatment on circulating endothelial progenitor cells in patients with mild essential hypertension.

It has been reported that the number of circulating endothelial progenitor cells (EPCs) reflects the endogenous vascular repair ability, with the EPCs pool declining in the presence of cardiovascular risk factors. However, their relationship with hypertension and the effects of anti-hypertensive treatment remain unclear. We randomized 29 patients with mild essential hypertension to receive barnidipine up to 20 mg or hydrochlorothiazide (HCT) up to 25 mg. Circulating EPCs were isolated from peripheral blood at baseline and after 3 and 6 months of treatment. Mononuclear cells were cultured with endothelial basal medium supplemented with EGM SingleQuots. EPCs were identified by positive double staining for both FITC-labeled Ulex europaeus agglutinin I and Dil-labeled acethylated low-density lipoprotein. After 3 and 6 months of treatment, systolic and diastolic blood pressure (BP) were significantly reduced. No difference was observed between drugs. An increase in the number of EPCs was observed after 3 and 6 months of anti-hypertensive treatment (p < 0.05). Barnidipine significantly increased EPCs after 3 and 6 months of treatment, whereas no effect was observed with HCT. No statistically significant correlation was observed between EPCs and clinical BP values. Our data suggest that antihypertensive treatment may increase the number of EPCs. However, we observed a different effect of barnidipine and HCT on EPCs, suggesting that, beyond its BP lowering effect, barnidipine may elicit additional beneficial properties, related to a healthier vasculature.

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.

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.

Effects of melatonin and Pycnogenol on small artery structure and function in spontaneously hypertensive rats.

It was suggested that oxidative stress has a key role in the development of endothelial dysfunction, as well as microvascular structural alterations. Therefore, we have investigated 2 substances with antioxidant properties: melatonin and Pycnogenol. We treated 7 spontaneously hypertensive rats (SHRs) with melatonin and 7 with Pycnogenol for 6 weeks. We compared results obtained with those observed in 7 SHRs and 7 Wistar-Kyoto normotensive control rats kept untreated. Mesenteric small resistance arteries were dissected and mounted on a wire myograph, and a concentration-response curve to acetylcholine was performed. Aortic contents of metalloproteinase 2, Bax, inducible NO synthase, and cyclooxygenase 2 were evaluated, together with the aortic content of total collagen and collagen subtypes and apoptosis rate. A small reduction in systolic blood pressure was observed. A significant improvement in mesenteric small resistance artery structure and endothelial function was observed in rats treated with Pycnogenol and melatonin. Total aortic collagen content was significantly greater in untreated SHRs compared with Wistar-Kyoto control rats, whereas a full normalization was observed in treated rats. Apoptosis rate was increased in the aortas of untreated SHRs compared with Wistar-Kyoto control rats; an even more pronounced increase was observed in treated rats. Bax and metalloproteinase 2 expressions changed accordingly. Cyclooxygenase 2 and inducible NO synthase were more expressed in the aortas of untreated SHRs compared with Wistar-Kyoto control rats; this pattern was normalized by both treatments. In conclusion, our data suggest that treatment with Pycnogenol and melatonin may protect the vasculature, partly independent of blood pressure reduction, probably through their antioxidant effects.

Hypertrophic remodeling of subcutaneous small resistance arteries in patients with Cushing's syndrome.

OBJECTIVE: Structural alterations of small resistance arteries in essential hypertensive patients (EH) are mostly characterized by inward eutrophic remodeling. However, we observed hypertrophic remodeling in patients with renovascular hypertension, in those with acromegaly, as well as in patients with non-insulin-dependent diabetes mellitus, suggesting a relevant effect of humoral growth factors on vascular structure, even independent from the hemodynamic load. Cortisol may stimulate the renin-angiotensin system and may induce cardiac hypertrophy. However, presently no data are available about small artery structure in patients with Cushing's syndrome. SUBJECTS: We have investigated the structure of sc small resistance arteries in 12 normotensive subjects (NT), in 12 EH subjects, and in eight patients with Cushing's syndrome (CS). Small arteries from sc fat were dissected and mounted on a micromyograph. The normalized internal diameter, media thickness, media to lumen ratio, and the media cross-sectional area were measured, as well as indices of oxidative stress. RESULTS: Demographic variables were similar in the three groups, except for clinic blood pressure. The media to lumen ratio was significantly greater in EH and CS, compared with NT; no difference was observed between EH and CS. The media cross-sectional area was significantly greater in CS compared with EH and with NT. An increased vascular oxidative stress was present in CS, as demonstrated by increased levels of superoxide anions, cyclooxygenase-1 and endothelial nitric oxide synthase in the microvessels. CONCLUSION: Our results suggest the presence of hypertrophic remodeling in sc small resistance arteries of CS, probably as a consequence of growth-promoting properties of circulating cortisol and/or increased vascular oxidative stress.