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Andrea Semplicini

Publications and source records attributed to Andrea Semplicini.

At least 19 recordsLinked to original sources
PubMed2006

A prospective study of the prevalence of primary aldosteronism in 1,125 hypertensive patients.

OBJECTIVES: We prospectively investigated the prevalence of curable forms of primary aldosteronism (PA) in newly diagnosed hypertensive patients. BACKGROUND: The prevalence of curable forms of PA is currently unknown, although retrospective data suggest that it is not as low as commonly perceived. METHODS: Consecutive hypertensive patients referred to 14 hypertension centers underwent a diagnostic protocol composed of measurement of Na+ and K+ in serum and 24-h urine, sitting plasma renin activity, and aldosterone at baseline and after 50 mg captopril. The patients with an aldosterone/renin ratio >40 at baseline, and/or >30 after captopril, and/or a probability of PA (by a logistic discriminant function) > or =50% underwent imaging tests and adrenal vein sampling (AVS) or adrenocortical scintigraphy to identify the underlying adrenal pathology. An aldosterone-producing adenoma (APA) was diagnosed in patients who in addition to excess autonomous aldosterone secretion showed: 1) lateralized aldosterone secretion at AVS or adrenocortical scintigraphy, 2) adenoma at surgery and pathology, and 3) a blood pressure decrease after adrenalectomy. Evidence of excess autonomous aldosterone secretion without such criteria led to a diagnosis of idiopathic hyperaldosteronism (IHA). RESULTS: A total of 1,180 patients (age 46 +/- 12 years) were enrolled; a conclusive diagnosis was attained in 1,125 (95.3%). Of these, 54 (4.8%) had an APA and 72 (6.4%) had an IHA. There were more APA (62.5%) and fewer IHA cases (37.5%) at centers where AVS was available (p = 0.002); the opposite occurred where AVS was unavailable. CONCLUSIONS: In newly diagnosed hypertensive patients referred to hypertension centers, the prevalence of APA is high (4.8%). The availability of AVS is essential for an accurate identification of the adrenocortical pathologies underlying PA.

Adrenal Cortex Neoplasms↗
PubMed2006

Vitamin C prevents zidovudine-induced NAD(P)H oxidase activation and hypertension in the rat.

OBJECTIVE: Cardiovascular risk is increased among HIV-infected patients receiving antiretroviral therapy due to the development of hypertension and metabolic abnormalities. In this study, we investigated the effects of long-term treatment with zidovudine (AZT) and vitamin C, alone and in combination, on blood pressure and on the chain of events linking oxidative stress to cardiac damage in the rat. METHODS: Six adult Wistar Kyoto rats received AZT (1 mg/ml) in the drinking water for 8 months, six vitamin C (10 g/kg of food) and AZT, six vitamin C alone, and six served as controls. RESULTS: AZT increased systolic blood pressure, expression of gp91(phox) and p47(phox) subunits of NAD(P)H oxidase, and protein kinase C (PKC) delta activation and reduced antioxidant power of plasma and cardiac homogenates. AZT also caused morphological alterations in cardiac myocyte mitochondria, indicative of functional damage. All of these effects were prevented by vitamin C. CONCLUSION: Chronic AZT administration increases blood pressure and promotes cardiovascular damage through a NAD(P)H oxidase-dependent mechanism that involves PKC delta. Vitamin C antagonizes these adverse effects of AZT in the cardiovascular system.

Animals↗
PubMed2006

Insulin generates free radicals in human fibroblasts ex vivo by a protein kinase C-dependent mechanism, which is inhibited by pravastatin.

Insulin can generate oxygen free radicals. Statins, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, exert a powerful antioxidant effect. The present study aimed to clarify the mechanisms through which insulin generates free radicals and to assess whether pravastatin modulates such effects. In cultured skin fibroblasts from human volunteers exposed to high insulin concentration, either in the presence or in the absence of pravastatin, insulin induced translocation of the p47(phox) subunit of NAD(P)H oxidase from the cytosol to the membrane and generation of radical oxygen species through a PKC delta-dependent mechanism. The insulin-induced translocation of p47(phox) was PKC delta dependent and attenuated by pravastatin, but independent of the activation of Akt and Rac1. Insulin-induced Akt phosphorylation was increased by pravastatin and ERK1/2 phosphorylation attenuated. The present study demonstrates a novel mechanism by which insulin stimulates the generation of free radicals in human fibroblasts, ex vivo. It involves phosphatidylinositol 3-kinase, PKC delta, and p47(phox) translocation and promotes ERK1/2 phosphorylation. Pravastatin inhibited radical oxygen species production by inhibiting PKC delta. These observations offer a robust explanation for the positive effects of pravastatin treatment in patients with insulin resistance syndrome.

Cells, Cultured↗
PubMed2006

Early markers of inflammation in a high angiotensin II state--results of studies in Bartter's/Gitelman's syndromes.

BACKGROUND: Inflammation has been increasingly recognized as playing a critical role in hypertension and atherosclerosis as reflected by overexpression and increased production of a variety of pro-inflammatory mediators. As angiotensin II (Ang II) also plays a major role in these diseases, the relationship between inflammation and Ang II has drawn increasing scrutiny. This study explores Ang II effects in Bartter's and Gitelman's syndromes (BS/GS) which do not develop hypertension and related cardiovascular remodelling and atherosclerosis, in spite of high Ang II levels and activation of the renin-angiotensin-aldosterone system while the NO system is up-regulated. METHODS: We evaluated the plasma levels of inflammation-associated markers, C-reactive protein (CRP), serum amyloid A (SAA), vascular cell adhesion molecules (VCAM) and intercellular adhesion molecules (ICAM), and the inflammation-related cytokines interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) using immunonephelometric and ELISA-based assays. RESULTS: The study demonstrated that all markers of inflammation except TNF-alpha, were unchanged in BS/GS (2.51+/-0.62 mg/l in BS/GS vs 1.7+/-0.6 in controls for CRP; 4.56+/-1.09 mg/l in BS/GS vs 4.51+/-1.0 for SAA; 1.84+/-0.27 ng/l in BS/GS vs 2.1+/-0.3 for IL-6; 449+/-83 ng/ml in BS/GS vs 410+/-92 for VCAM and 234+/-26 ng/ml in BS/GS vs 185+/-22 for ICAM), while TNF-alpha was increased (10.5+/-2.03 vs 3.68+/-0.2, P = 0.0001). CONCLUSIONS: The results of this study stress the critical role played by Ang II in controlling vascular biology including inflammation-related processes as well as highlighting the utility of BS/GS in investigating these pathways.

Acute-Phase Proteins↗
PubMed2006

Antioxidant effect of L-carnitine and its short chain esters: relevance for the protection from oxidative stress related cardiovascular damage.

BACKGROUND: Increased oxidative stress is associated with all cardiovascular risk factors and reactive oxygen species appear to be the principal mediators of cardiomyocite dysfunction in various cardiovascular diseases. Carnitine has been shown to be effective in pathologic conditions characterized by increased oxidative stress and an antioxidant effect of L-carnitine and its derivatives has been described but the specific mechanism is unclear. METHODS: We evaluated in human endothelial cells in culture the effect of L-carnitine (C), acetyl-L-carnitine (AC) and propionyl-L-carnitine (PC) on gene and protein expression (RT-PCR and Western blot) of oxidative stress related proteins heme oxygenase-1 (HO-1) and of endothelial NO synthase (ecNOS) in absence and presence of oxidative stress induced by H2O2. RESULTS: HO-1 as well as ecNOS gene and protein expression significantly increased upon Carnitines incubation. Induction of oxidative stress increased HO-1 gene expression compared to basal condition (0.62+/-0.02 densitometric units vs. 0.48+/-0.05, p<0.01) while decreased ecNOS gene expression (0.75+/-0.04 vs. 0.40+/-0.08, p<0.001). These results were paralleled by similar results at protein level. Coincubation of C (0.5-1.0-2.0 mM), AC (0.1-0.2-0.4 mM) and PC (0.05-0.1-0.2 mM) with H2O2 further increased HO-1 gene expression and not only normalized vs. H2O2 but even increased vs. basal ecNOS mRNA. HO-1 and ecNOS gene expression was also paralleled at protein level by coincubation with C, AC and PC of cells exposed to oxidative stress. CONCLUSION: This is the first report that has utilized a molecular biological approach to demonstrate a direct stimulatory effect of Carnitines on gene and protein expression of the oxidative stress related markers HO-1 and ecNOS. As HO-1 and NO are known as antioxidant, antiproliferative and anti-inflammatory, their increased expression would be expected to protect from oxidative stress related cardiovascular risk factors and myocardial damage, therefore adding this effect to the multiple pathways involved in the effects of carnitines.

Apoptosis↗
PubMed2006

Aldosterone and refractory hypertension: a prospective cohort study.

BACKGROUND: Resistant hypertension is common in clinical practice. The aim of our study was to evaluate inappropriate aldosterone activity in causing resistance to antihypertensive therapy. METHODS: Among the patients consecutively evaluated for the first time between 1995 and 2001, we selected all those (n = 157) with an aldosterone-to-renin ratio (ARR) >or=25 (ng/dL)/(ng/mL/h), and plasma aldosterone >or=12 ng/dL. Eight patients with Conn adenoma were excluded from the study. Fifty-eight were diagnosed as idiopathic aldosteronism (IHA), the other 91 patients, who did not meet the criteria for primary aldosteronism, were operatively classified as aldosterone-associated hypertension (AAH). As a control group, we randomly chose 160 patients with essential hypertension and plasma aldosterone <12 ng/dL (EH). Antihypertensive treatment was given in accordance to World Health Organization Guidelines (1999). The study end point was blood pressure (BP) <140/90 mm Hg. RESULTS: During follow-up (22 +/- 2 months), 24 (41.4%) patients with IHA, 35 (38.5%) with AAH, and 72 (54.0%) with EH reached the end point. According to survival analysis, AAH and IHA patients reached the end point in a smaller fraction and in a longer time compared with EH patients, with no difference between IHA and AAH. At the end of follow-up, IHA and AAH patients had higher diastolic BP than EH patients with no difference between IHA and AAH. CONCLUSIONS: Patients with elevated aldosterone plasma levels develop resistant hypertension, even in the absence of clinically diagnosed primary aldosteronism. Their identification will allow a targeted therapy and a more effective BP reduction.

Aldosterone↗
PubMed2006

Angiotensin II-stimulated collagen production in cardiac fibroblasts is mediated by reactive oxygen species.

OBJECTIVE: The aim of the present study was to determine whether inhibition of reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] oxidase and of various superoxide generating systems could affect the collagen production, the mRNA and protein expression of collagen types I and III in control and angiotensin II-treated cardiac fibroblasts. METHODS: Cardiac fibroblasts from passage 2 from normal male adult rats were cultured to confluency and incubated in serum-free Dulbecco's modified Eagle's medium for 24 h. The cells were then preincubated with(out) the tested inhibitors for 1 h and then further incubated with(out) angiotensin II (1 micromol/l) for 24 h. Collagen production was measured spectrophotometrically with picrosirius red as dye and with [3H]proline incorporation; collagen type I and III content by enzyme-linked immunosorbent assay and collagen type I and III mRNA expression by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). NAD(P)H-dependent superoxide anion production was assayed as superoxide dismutase-inhibitable cytochrome c reduction. Intracellular formation of reactive oxygen species was assessed with 2',7'-dichlorofluorescein diacetate as fluorescent probe. RESULTS: Angiotensin II stimulated the collagen production, the collagen I and III content and mRNA expression in cardiac fibroblasts, and apocynin, a membrane NAD(P)H oxidase inhibitor, abolished this induction. Rotenone, allopurinol, indomethacin, nordihydroguiaretic acid, ketoconazole and nitro-L-arginine (inhibitors of mitochondrial NAD(P)H oxidase, xanthine oxidase, cyclooxygenase, lipoxygenase, cytochrome P450 oxygenase and nitric oxide synthase, respectively) did not affect the angiotensin II-induced collagen production. Angiotensin II increased the NAD(P)H-dependent superoxide anion production and the intracellular generation of reactive oxygen species in cardiac fibroblasts, and apocynin abrogated this rise. CONCLUSIONS: Our data show that in adult rat cardiac fibroblasts the membrane-associated NAD(P)H oxidase complex is the predominant source of superoxide anion and reactive oxygen species generation in angiotensin II-stimulated adult cardiac fibroblasts. Inhibition of this NAD(P)H oxidase complex with apocynin completely blocked the angiotensin II-stimulated collagen production, and collagen I and III protein and mRNA expression.

Acetophenones↗
PubMed2006

Reduced expression of regulator of G-protein signaling 2 (RGS2) in hypertensive patients increases calcium mobilization and ERK1/2 phosphorylation induced by angiotensin II.

CONTEXT: RGS2 (regulators of G-protein signaling) is a negative regulator of Galphaq protein signaling, which mediates the action of several vasoconstrictors. RGS2-deficient mouse line exhibits a hypertensive phenotype and a prolonged response to vasoconstrictors. OBJECTIVE: To compare RGS2 expression in peripheral blood mononuclear cells (PBMs) and cultured fibroblasts from normotensive subjects and hypertensive patients. METHODS: PBMs were isolated from 100 controls and 150 essential hypertensives. Additionally, fibroblasts were isolated from skin biopsy of 11 normotensives and 12 hypertensives and cultured up to the third passage. Quantitative mRNA and protein RGS2 expression were performed by real-time quantitative reverse transcriptase-polymerase chain reaction and by immunoblotting, respectively. Free Ca measurement was performed in monolayers of 24-h serum-deprived cells, using FURA-2 AM. Phosphorylation of the extracellular signal-regulated kinases ERK1/2 was measured by immunoblotting. Polymorphism (C1114G) in the 3' untranslated region of the RGS2 gene was investigated by direct sequencing and real-time polymerase chain reaction (PCR). RESULTS: RGS2 mRNA expression was significantly lower in PBM and in fibroblasts from hypertensives, in comparison to normotensives. C1114G polymorphism was associated with RGS2 expression, with the lowest values in GG hypertensives. The 1114G allele frequency was increased in hypertensives compared with normotensives. Angiotensin II-stimulated intracellular Ca increase and ERK1/2 phosphorylation were higher in fibroblasts from hypertensive patients compared with control subjects, and in those with the G allele, independently of the blood pressure status. The angiotensin II-stimulated Ca mobilization and ERK1/2 phosphorylation were negatively correlated with RGS2 mRNA expression. CONCLUSION: Low expression of RGS2 contributes to increased G-protein-coupled signaling in hypertensive patients. The allele G is associated with low RGS2 expression and blood pressure increase in humans.

Adult↗
PubMed2006

Blood pressure in acute ischemic stroke and mortality: a study with noninvasive blood pressure monitoring.

BACKGROUND: In acute ischemic stroke, a transient elevation of blood pressure is common; its significance and its relationship with the neurological outcome are still unclear. METHODS: In 71 consecutive patients with acute ischemic stroke, aged 25-94 years, admitted to our unit, we investigated the relationships between the blood pressure variation during the first 24 h and mortality at 3 months (study endpoint). Neurological status was assessed with the National Institutes of Health Stroke Scale. Blood pressure was measured with bedside noninvasive blood pressure monitoring every 15 min. The mean of four measurements at the emergency department and the mean of 12 measures (during a 3-h interval) at 12 and at 24 h after stroke onset were considered for analysis. Antihypertensive treatment was given in accordance with the Recommendations for Stroke Management of European Stroke Initiative. RESULTS: In the whole series, 21% were atherothrombotic, 32% cardioembolic, 34% lacunar, and 13% of unknown or other cause. Blood pressure was 160+ or -3/86+ or -2 mmHg at the emergency department, 148+ or -3/82+ or -2 mmHg at 12 h, and 147+ or -3/81+ or -2 mmHg at 24 h (P<0.05). Four patients (11%) of those in whom mean blood pressure decreased >5 mmHg, and 12 (33%) of the others, in whom mean blood pressure decreased < or =5 mmHg or did not decrease, reached the endpoint (P<0.05). According to the multivariate Cox model, NIHSS score at the emergency department (95% confidence interval: 1.025-1.238, P=0.013) and age (95% confidence interval: 1.007-1.259, P=0.038) were predictors of reaching the endpoint, whereas mean blood pressure reduction 24 h after stroke onset had a protective effect (95% confidence interval: 0.845-0.995, P=0.038). Diabetes, mean blood pressure at the emergency department and the need for antihypertensive therapy did not correlate with the outcome. CONCLUSIONS: Noninvasive blood pressure monitoring during the first 24 h of acute ischemic stroke may be useful in the prognostic stratification by showing moderate blood pressure decrease, either spontaneous or drug induced, which is associated with a favorable prognosis at 3 months.

Adult↗
PubMed2006

Effect of doxazosin on oxidative stress-related proteins in benign prostatic hyperplasia.

BACKGROUND AND OBJECTIVES: Oxidative stress can induce cell mutations or proliferation which then can progress to carcinogenesis or remodeling. The same oxidative stress-mediated mechanism could participate in prostate cell proliferation and remodeling present in benign prostatic hyperplasia (BPH). Doxazosin induces prostate epithelial and stromal cell apoptosis through production of transforming growth factor-beta (TGF-beta), but cellular mechanisms are not completely clarified. In 10 prostate samples from BPH untreated patients who underwent TUR, we have assessed the gene and protein expression of: p22(phox) (subunit of NAD(P)H oxidase essential for O(2)(-) production); heme oxygenase-1 (HO-1) (induced by oxidative stress and antiapoptotic); TGF-beta (inhibitor of prostatic epithelial and stromal cell growth); the in vitro effect of doxazosin on expression of these markers. METHODS: RT-PCR and Western blot with specific primers and antibodies. p22(phox), HO-1 and TGF-beta were quantified by the ratio between their PCR and Western blot products and GAPDH. RESULTS: Doxazosin significantly reduced p22(phox) gene and protein expression (0.61 +/- 0.04 vs. 0.36 +/- 0.04 d.u., p < 0.0002; 0.85 +/- 0.03 vs. 0.47 +/- 0.03, p < 0.0001, respectively). Doxazosin concentration dependently reduced HO-1 gene and protein expression (0.57 +/- 0.07 vs. 0.49 +/- 0.06 d.u. (1 microM) p < 0.04, vs. 0.22 +/- 0.08 (10 microM) p < 0.0001; 0.78 +/- 0.04 vs. 0.44 +/- 0.1 (10 microM) p < 0.003 respectively) and increased TGF-beta protein expression (0.58 +/- 0.05 vs. 0.74 +/- 0.16 (1 microM) n.s. vs. 0.81 +/- 0.07 (10 microM) p < 0.01). CONCLUSIONS: Induction of oxidative stress-related proteins seems to be involved in the prostate cell proliferation and remodeling present in BPH. Doxazosin may reduce oxidative stress through reduction of p22(phox). Surprisingly, HO-1, which is induced and protected by oxidative stress, is also reduced by doxazosin. HO-1 is a potent antiapoptotic factor and downregulator of TGF-beta. From the results of this preliminary study it could be proposed that the proapoptotic effect of doxazosin could be mediated, at least in part, through the contemporary inhibition of HO-1.

Aged↗
PubMed2005

Diagnostic tools for the study of vascular cognitive dysfunction in hypertension and antihypertensive drug research.

Arterial hypertension is one of the main risk factors for cerebrovascular diseases, and antihypertensive treatment has significantly reduced their associated mortality. However, morbidity has not been reduced to a similar extent and a still increasing number of patients suffers from recurring strokes and from the disabling consequences of cerebrovascular diseases and develops progressive cognitive impairment. It is still debated to what extent antihypertensive treatment may prevent the development of cognitive dysfunction, due to the lack of a focused approach to vascular cognitive impairment, to the lack of a systematic study of the early phases of dementia, and to the use of diagnostic tests that are not sensitive and specific for a slow onset clinical condition, such as dementia. The aim of the present expert consensus report is to enlist the diagnostic tools that are currently available to assess mild cognitive impairment (MCI) and early dementia and that are sensitive and specific enough to be used in observational, longitudinal, and interventional clinical research studies, aiming to investigate the impact of antihypertensive drugs on vascular dementia (VD).

Animals↗
PubMed2005

Reduced mRNA and protein content of rho guanine nucleotide exchange factor (RhoGEF) in Bartter's and Gitelman's syndromes: relevance for the pathophysiology of hypertension.

BACKGROUND: Activation of RhoA/Rho kinase (ROK) pathway by angiotensin II (Ang II) is involved in the pathophysiology of hypertension and remodeling. In Bartter's and Gitelman's syndrome (BS/GS), the short-term and long-term signaling of Ang II are blunted. The BS/GS have also reduced expression and response on Ang II challenge of ROK, which indicate downregulation of RhoA/ROK pathway. As causes for RhoA/ROK downregulation in BS/GS, we hypothesized an alteration at the level of the upstream regulators of RhoA such as reduced expression of Rho guanine nucleotide exchange factor (RhoGEF), which links activation of G protein-coupled receptors to RhoA/ROK signaling or increased guanine nucleotide dissociation inhibitor (RhoGDI), which inhibits dissociation of GDP from GDI maintaining RhoA in an inactive state. METHODS: In mononuclear cells of 9 BS/GS and 9 healthy controls (C), we looked at gene and protein expression (reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot) of RhoA, RhoGEF, and RhoGDI. RESULTS: In BS/GS RhoA gene and protein expression were not different from C. Also RhoGDI mRNA and protein levels were not different. On the contrary, p115RhoGEF mRNA and protein levels were reduced in BS/GS. CONCLUSIONS: Reduced p115RhoGEF may explain the downregulation of RhoA/ROK pathway in BS/GS. This is the first report of upstream regulators of RhoA level in BS/GS, a human clinical condition characterized by reduced vascular tone regulation. Because BS/GS represent the mirror image of derangements involved in hypertension, the reduced RhoGEF expression in BS/GS underlines a major impact of RhoA/ROK pathway on blood pressure regulation and confirms BS/GS as a good human model for exploring mechanisms involved in the pathophysiology of hypertension and remodeling.

Adult↗