Guido A. M. Tiberio

Relations Between Cardiac and Vascular Structure in Patients With Primary and Secondary Hypertension

BACKGROUND Data on cardiac and vascular structure in secondary hypertension are generally scarce, and no data on the interrelations between cardiac mass and structural characteristics of the vessel wall, both in large and in small resistance arteries, are presently available. OBJECTIVES The aim of this study was to investigate the relation between structural changes in subcutaneous small arteries, left ventricular mass and wall thickness of the common carotid artery in patients with primary and secondary hypertension. METHODS Seventy-four subjects were included in the study: 11 patients with pheochromocytoma, 14 with primary aldosteronism (PA), 19 with renovascular hypertension (RVH), 18 with essential hypertension (EH) and 12 normotensive (NT) control subjects. All subjects were submitted to a biopsy of subcutaneous fat. Morphologic characteristics of subcutaneous small resistance arteries (relaxed diameter <300 microm) were directly evaluated using a micromyographic technique. All subjects were submitted to calculation of left ventricular mass index (LVMI) and common carotid artery intima-media thickness (CCIMT), using ultrasound technique. RESULTS The correlation coefficients between the media to lumen ratio in subcutaneous small arteries (M/L) and LVMI or between M/L and CCIMT were closer in RVH than in pheochromocytoma, EH or NT; in PA the correlation coefficients were slightly less close than those in RVH. An excess prevalence of carotid plaques in RVH was observed. CONCLUSIONS A close relation between small resistance artery morphology and cardiac or carotid artery structure may be observed in those hypertensive patients in whom the renin-angiotensin-aldosterone system is activated. In constrast, in NT, EH and pheochromocytoma no significant correlation between M/L and LVMI or CCIMT was observed.

Immunohistochemical evaluation of microvascular rarefaction in hypertensive humans and in spontaneously hypertensive rats

OBJECTIVE No data are presently available about changes in capillary density in the skeletal muscle and in the brain of spontaneously hypertensive rats (SHR) in relation to the development of hypertension. DESIGN AND METHODS We have investigated 4 week-old and 12 week-old SHR and age-matched normotensive Wistar-Kyoto controls (WKY). Microvessel density (MVD) in the cerebral cortex and in a skeletal muscle were evaluated in sections stained for CD31. We also evaluated MVD in the dermal tissue of normotensive subjects and essential hypertensive patients. Subcutaneous small resistance arteries were dissected and mounted in a micromyograph and the media to lumen ratio (M/L) was measured. RESULTS A significant reduction in MVD in the skeletal muscle and in the brain of SHR was clearly observed at 12 weeks of age, after the development of hypertension, but not at 4 weeks of age (pre-hypertensive condition). In hypertensive patients a significant reduction in the dermal MVD and an inverse correlation between M/L and MVD was observed. CONCLUSIONS Our results suggest that, in the brain and skeletal muscle of adult SHR after the development of hypertension, and in the derma of adult essential hypertensive patients microvascular rarefaction may occur.

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 Cushings 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 Cushings 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.

Lack of prognostic role of endothelial dysfunction in subcutaneous small resistance arteries of hypertensive patients

Objective The presence of endothelial dysfunction in the coronary circulation or in the brachial artery has been found to be associated with a greater incidence of cardiovascular events. However, no data are presently available about the prognostic role of endothelial dysfunction in human small resistance arteries. Design and methods Ninety subjects were included in the present study. They were: 10 normotensive subjects, 36 patients with essential hypertension, 10 patients with phaeochromocytoma, 11 patients with primary aldosteronism, 10 patients with renovascular hypertension, and 13 normotensive patients with non-insulin-dependent diabetes mellitus (NIDDM). 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 the concentration–response curves to acetylcholine (from 10−9 to 10−5 mol/l) (endothelium-dependent vasodilatation) and sodium nitroprusside (from 10−9 to 10−5 mol/l) (endothelium-independent vasodilatation) after precontraction of the vessels with norepinephrine were evaluated. The subjects were re-evaluated (by clinical visits or telephone interviews) after an average follow-up time of 5.5 years. Results Twenty-nine subjects had a documented fatal or non-fatal cardiovascular event (5.87%/year). The endothelium-dependent vasodilatation in the subcutaneous small arteries was similar in subjects with or without cardiovascular events. Also, endothelium-independent vasodilatation to sodium nitroprusside was similar in the two groups. Similar results were obtained by subdividing patients in the different subgroups (essential hypertension, secondary hypertension, etc.). Conclusions Our results indicate that endothelial dysfunction in the microcirculation does not predict cardiovascular events. It is possible that a prognostic role of endothelial dysfunction may be observed when other vascular districts prone to atherosclerosis are evaluated, or it might be detected only in patients at low to medium cardiovascular risk, in whom endothelial dysfunction is less advanced.

Long-Term Outcomes of Adjuvant Mitotane Therapy in Patients With Radically Resected Adrenocortical Carcinoma

Context In 2007, a retrospective case-control study provided evidence that adjuvant mitotane prolongs recurrence-free survival (RFS) in patients with radically resected adrenocortical carcinoma (ACC). Objective and Design We aimed to confirm the prognostic role of adjuvant mitotane in the same series after 9 additional years of follow-up. Setting, Patients, and Interventions One hundred sixty-two ACC patients who did not recur or die after a landmark period of 3 months were considered. Forty-seven patients were enrolled in four Italian centers where adjuvant mitotane was routinely recommended (mitotane group), 45 patients in four Italian centers where no adjuvant strategy was undertaken (control group 1), and 70 German patients left untreated after surgery (control group 2). Main Outcome Measures The primary aim was RFS, the secondary was overall survival. Results An increased risk of recurrence was found in both control cohorts [group 1: hazard ratio (HR) = 2.98; 95% confidence interval (CI), 1.75 to 5.09; P < 0.0001; group 2: HR = 2.61; 95% CI, 1.56 to 4.36; P < 0.0001] compared with the mitotane group. The risk of death was higher in control group 1 (HR = 2.03; 95% CI, 1.17 to 3.51; P = 0.011) but not in control group 2 (HR = 1.60; 95% CI, 0.94 to 2.74; P = 0.083), which had better prognostic factors and more aggressive treatment of recurrences than control group 1. The benefit of adjuvant mitotane on RFS was observed regardless of the hormone secretory status. Conclusions Adjuvant mitotane is associated with prolonged RFS, without any apparent influence by the tumor secretory status. The retrospective nature of the study is a major limitation.

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.

Effects of Insulin on Endothelial and Contractile Function of Subcutaneous Small Resistance Arteries of Hypertensive and Diabetic Patients

The effect of insulin on the vasoconstriction induced by norepinephrine is at present controversial. We have previously demonstrated that high-concentration insulin may induce an increased reactivity to norepinephrine in mesenteric small resistance arteries of spontaneously hypertensive rats. The aim of the present study was to evaluate the effects of low- and high-concentration insulin on the concentration-response curves to norepinephrine and acetylcholine in subcutaneous small resistance arteries of hypertensive and diabetic patients. Twelve normotensive subjects (NT), 11 patients with essential hypertension (EH), 8 patients with non-insulin-dependent diabetes mellitus (NIDDM), and 8 patients with both EH and NIDDM (EH + NIDDM) were included in the study. Subcutaneous small resistance arteries were dissected and mounted on an isometric myograph. Concentration-response curves to norepinephrine (from 10–8 to 10–5 mol/l) and acetylcholine (from 10–9 to 10–5 mol/l) were performed in the presence or absence of insulin 715 pmol/l (low concentration) and 715 nmol/l (high concentration). A significant reduction in the contractile response to norepinephrine was observed in NT after preincubation of the vessels with both low- and high-concentration insulin. No reduction was observed in NIDDM and EH + NIDDM, while a significant decrease was obtained in EH with high-concentration insulin. Moreover, a significant difference in reduction in contractile response at maximal concentration of norepinephrine in the presence of low-concentration insulin was observed in NT compared to EH (p = 0.03), NIDDM (p = 0.02), and EH + NIDDM (p = 0.05), whereas no difference was observed with high-concentration insulin. No differences in the concentration-response curves to acetylcholine before or after precontraction with either low- or high-concentration insulin were observed in any group. In conclusion, insulin at low (physiological) concentrations seems to induce a decreased reactivity to norepinephrine in subcutaneous small resistance arteries of NT, but this effect was lost in EH, NIDDM and EH + NIDDM. This effect does not seem to involve acetylcholine-stimulated nitric oxide release.

Role of ET A Receptors in the Vasoconstriction Induced by Endothelin-1 in Subcutaneous Small Arteries of Normotensive Subjects and Hypertensive Patients

Objective: The aim of our study was to investigate contractile responses to endothelin-1 in the presence or absence of selective blockers of ET A or ET B receptors in subcutaneous small resistance arteries of normotensive subjects and of patients with essential hypertension. Methods: Twenty-four subjects (eight normotensives aged 50 - 4 years, and 16 with essential hypertension aged 53 - 4 years) were included in the study. All subjects were submitted to a biopsy of the subcutaneous fat. Small resistance arteries (internal diameter 160-280 µm) were dissected and mounted on a micromyograph as a ring preparation (Mulvanys technique). The media-to-lumen ratio was calculated. A concentration-response curve to endothelin-1 was then performed in the presence or absence of FR 139317, (a selective blocker of ET A receptors) or of BQ 788, (a selective blocker of ET B receptors). Results: The media-to-lumen ratio was lower in normotensives compared with those subjects with essential hypertension (0.08 - 0.02 vs. 0.12 - 0.05, p < 0.01). The vasoconstriction induced by endothelin-1 was greater in normotensives than in patients with essential hypertension. In normotensives, almost all the vasoconstriction induced by endothelin-1 was blocked by the addition of FR 139317, while in subjects with essential hypertension the effect was smaller. The selective blocker of ET B was devoid of effect in both groups. Conclusions: The vasoconstrictor effect of endothelin-1 in small resistance arteries of normotensive subjects and, in part, also in hypertensive patients is mediated by ET A receptors, while ET B receptors play a minor role, if any. It is, however, possible that a vasoconstrictor effect mediated by ET B receptors located on vascular smooth muscle cells may be masked by the simultaneous stimulation of endothelial ET B receptors which may induce a vasodilation mediated by nitric oxide.

Advanced sealing and dissecting devices in laparoscopic adrenal surgery.

The use of advanced sealing devices was associated with reduced operative time, particularly with left adrenalectomy.

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

Abstract 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.