Plasma adiponectin for prediction of cardiovascular events and mortality in high-risk patients.

CONTEXT: The prognostic value of plasma levels of adiponectin, an adipocytokine with antiatherogenic, antiinflammatory, and insulin-sensitizing effects, is contentious. OBJECTIVE: The objective of the study was to investigate whether plasma adiponectin levels predict cardiovascular (CV) events and mortality in high-risk coronary artery disease (CAD) patients. DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME MEASURE: We measured plasma adiponectin and examined its impact on the incidence of CV deaths and events at follow-up in the context of all potentially relevant background covariates in 712 high-risk patients of the Genetic and ENvironmental factors in Coronary Atherosclerosis study who underwent coronary angiography for suspected CAD. Based on the population plasma adiponectin median (6.38 microg/ml, interquartile range 4.2-10.2), we split the patients in a high- and a low-plasma adiponectin subgroup. After a median follow-up of 3.8 years (interquartile range 3.3-4.3 yr), outcome data were obtained in 100% of the patients and 45 CV deaths (6.4%) were recorded. Kaplan-Meier analysis unexpectedly showed a higher CV death rate in high-plasma adiponectin than low-plasma adiponectin patients. By contrast, multivariate Cox regression analysis, in which potential confounders, including ongoing medical treatment, were considered, showed no impact of plasma adiponectin on CV death. Similar negative results were obtained using the propensity score that considered all relevant covariables and medical treatment rate, which differed between the high- and low-plasma adiponectin group. CONCLUSIONS: In high-risk CAD patients, plasma adiponectin above the median (6.38 microg/ml) implies a paradoxical higher risk of CV death. However, when relevant covariates that differ between high- and low-plasma adiponectin groups are considered, this association wanes, indicating that the clustering of plasma adiponectin with other covariates can abolish its impact on CV prognosis.

Prevention of hypertension, cardiovascular damage and endothelial dysfunction with green tea extracts.

BACKGROUND: We investigated the effect of green tea extract (GTE) in arterial hypertension with high oxidative stress. Angiotensin (Ang) II induces endothelial dysfunction (ED) that is crucial for the development of atherosclerosis and hypertension. METHODS: Male Sprague-Dawley rats, 13 weeks old, randomly assigned to drinking water with or without GTE (6 mg/mL) received a vehicle, a high (700 microg/kg/d) or a low (350 microg/kg/d) Ang II dose for 13 days, by osmotic mini-pumps. Blood pressure (BP) was measured with telemetry. After sacrifice, left ventricular (LV) mass index, small mesenteric artery media-to-lumen ratio, and concentration-response curves of phenylephrine-precontracted arteries to acetylcholine were evaluated. The effect of the superoxide dismutase (SOD-1) analog tempol on artery responses to acetylcholine was assessed. Oxidative stress was measured by plasma hydroperoxides and nitrotyrosine levels. The mRNA of heme oxygenase 1 (HO-1), NADPH oxidase endothelial p22(phox) subunit, and SOD-1 was also measured in the aorta. RESULTS: Compared with vehicle high Ang II increased BP, LV mass index, media-to-lumen ratio, and hydroperoxide radicals. The GTE blunted these increases, prevented the increase in HO-1, p22(phox), and SOD-1 mRNA in aorta caused by Ang II, and reduced them below baseline levels. Low Ang II dose increased BP values and plasma hydroperoxides only during the first week. Both Ang II doses shifted rightward the curves to acetylcholine; this was prevented in vivo by GTE and abolished in vitro by tempol. CONCLUSIONS: The GTE prevented hypertension and target organ damage induced by a high Ang II dose, likely by prevention or scavenging of superoxide anion generation.

Identification of the mineralocorticoid receptor in human spermatozoa.

Aldosterone seems to play a role in the regulation of the electrolyte content of sperm and in the motility of spermatozoa. The aim of the study was to evaluate the presence of the mineralocorticoid receptor (MR) in human ejaculated spermatozoa. We have assayed MR on spermatozoa of freshly ejaculated sperm from healthy donors. The identification of MR was made by using immunohistochemistry and immunofluorescence analyses, while MR mRNA expression was evaluated by real-time PCR assay. The immunohistochemical and immunofluorescence analyses showed positive staining both in the midpiece and in the tail of the spermatozoa. Relative quantification of MR by using real-time PCR shows that the mRNA expression of MR in spermatozoa is lower than in mononuclear leukocytes (positive controls). Sequencing showed complete identity between the sequence obtained from spermatozoa and the human MR cDNA sequence. Further studies should be performed in order to elucidate a possible physiological role of aldosterone in regulating electrolyte concentration, and the pro-oxidant effect of excess aldosterone in this new target tissue.

The T(-786)C endothelial nitric oxide synthase genotype predicts cardiovascular mortality in high-risk patients.

OBJECTIVES: This study sought to investigate the impact of a common T(-786)C single-nucleotide polymorphism (SNP) in the promoter of the endothelial nitric oxide synthase (eNOS, NOS3) gene on cardiovascular (CV) death in a prospective cohort study. BACKGROUND: The T(-786)C SNP eNOS gene implies a blunted endothelium-dependent vasodilation in hypertensive patients and was associated with multivessel coronary artery disease in cross-sectional studies, but it remained unsettled whether it carried prognostic information. METHODS: In consecutive white patients of the GENICA (Genetic and Environmental Factors in Coronary Atherosclerosis) study, who underwent coronary angiography between 1999 and 2001, we determined the incidence of CV death at follow-up. The eNOS T(-786)C and the exon 7 G(894)T SNPs were determined by melting curve analysis of amplicons from allele-specific fluorescence resonance energy transfer probes. Plasma levels of nitrate/nitrite, nitrotyrosine, and myeloperoxidase were also measured. The Kaplan-Meier and Cox regression analyses were used to assess the impact of SNPs on event-free survival. RESULTS: Complete follow-up data were obtained in 1,086 (98%) patients. After a median follow-up of 1,296 days (range 4 to 2,057 days), we observed 85 (8.2%) CV deaths. There was a significant impact of the T(-786)C eNOS genotype on CV death-free (p = 0.0102) survival, but no differences in CV death rates across G(894)T genotypes. The TT individuals, who showed a lower survival, exhibited higher plasma myeloperoxidase (p < 0.0001) and lower levels of nitrotyrosine (p < 0.0001) than CC patients. CONCLUSIONS: The T(-786)C SNP in the promoter of eNOS bears independent prognostic information and is associated with changes in markers of oxidant stress in high-risk white patients referred for coronary angiography.

The renal antifibrotic effects of angiotensin-converting enzyme inhibition involve bradykinin B2 receptor activation in angiotensin II-dependent hypertension.

OBJECTIVE: The renoprotective action of angiotensin I-converting enzyme inhibitors (ACE-Is) is well established, but the role played by bradykinin (BK) remains unclear. We therefore investigated whether an enhanced BK effect on B2 receptor subtype mediated the antifibrotic effect of ACE-Is and whether neutral endopeptidase (NEP) inhibition, which can blunt BK degradation more effectively than ACE inhibition, provided further renoprotection in a rat model of angiotensin (Ang) II-dependent renal damage. METHODS: Five-week-old Ren-2 transgenic rats (TGRen2) received, for 8 weeks, a placebo, ramipril (5 mg/kg body weight) or the dual ACE + NEP inhibitor MDL 100,240 (MDL) (40 mg/kg body weight). After 4 weeks, the B2 receptor antagonist icatibant (0.5 mg/kg body weight) was administered on top of active treatment for 4 weeks to 50% of the TGRen2 rats. Blood pressure was measured weekly by a tail-cuff method and, after sacrifice, kidney weight, glomerular volume, density of glomerular profiles were measured; tubulo-interstitial fibrosis, glomerular and perivascular fibrosis were quantified by histomorphometry. RESULTS: The development of hypertension and tubulo-interstitial fibrosis was prevented by both ramipril and MDL (P = 0.0001 versus placebo); icatibant annulled the latter effect. Glomerular and perivascular fibrosis were unaffected by either ramipril or MDL alone; however, combined treatment with icatibant enhanced glomerular fibrosis (P = 0.0001 versus placebo). CONCLUSION: Enhanced BK effect on B2 subtype receptors is essential for the prevention of tubulo-interstitial fibrosis with ACE or dual ACE + NEP inhibition in TGRen2 rats.

Adiponectin receptor expression in the human adrenal cortex and aldosterone-producing adenomas.

Adiponectin is an adipocyte-derived circulating peptide that plays an important role in adipose tissue metabolism, insulin sensitivity and cardiovascular disease. The adrenal gland, by secreting glucorticoid and mineralocorticoid hormones, intervenes in cardiovascular and glucose metabolism regulation and is surrounded by adipose tissue. Hence, we investigated the hypothesis that adiponectin receptor types 1 and 2 (adipo-R1 and adipo-R2) are expressed in the human adrenal gland and in adrenocortical zona glomerulosa cell-derived aldosterone-producing adenoma (APA) tissue. We used real-time reverse transcription-polymerase chain reaction to demonstrate the mRNA of adipo-R1 and adipo-R2 in 10 histologically normal human adrenal cortexes that were obtained from patients with renal cancer undergoing nephrectomy with ipsilateral adrenalectomy and in 10 APAs. Melting curve analysis and sequencing were used to confirm the specificity of the amplicons obtained. Results consistently showed the expression of specific mRNAs of adiponectin receptors in all histologically normal human adrenal cortexes and APAs. This novel finding suggests that adiponectin could play a regulatory role in adrenocortical function and growth in humans.

Hyperhomocysteinemia predicts total and cardiovascular mortality in high-risk women.

OBJECTIVE: The impact of homocysteine on cardiovascular disease can be more detrimental in women than in men, but it is unknown whether this applies to high-risk women. We therefore investigated the association of hyperhomocysteinemia with coronary artery disease (CAD) and cardiovascular mortality in high-risk women referred for CAD, both in the total population and in the hypertensive and normotensive cohorts. DESIGN: A prospective study cohort. SETTING: A tertiary centre. INCLUSION CRITERIA: 262 consecutive Caucasian postmenopausal women referred for coronary angiography. EXCLUSION CRITERIA: acute myocardial infarction and vitamin supplementation. MAIN OUTCOME MEASURE(S): We assessed total plasma homocysteine (tHcy), folate levels, and the MTHFR677C-->T polymorphism. CAD was defined as a modified Duke Index score greater than 0; hyperhomocysteinemia as tHcy levels of 15 micromol/l or greater. The primary study outcome was cardiovascular mortality at follow-up. RESULTS: Mild/moderate and severe hyperhomocysteinemia was found in 15.1 and 1.6% of women, respectively, without differences between CAD and non-CAD women. By the ATPIII criteria, 92.2% of the women were in the highest risk class and 55% had CAD; however, no association of tHcy with the CAD score was found. After a median follow-up of 3.6 years, 23 women (9.1%) had died, 15 (6%) of cardiovascular causes. Women with high tHcy levels showed the worst all-cause and cardiovascular death-free survival at Kaplan-Meier and Cox regression analysis. Moreover, in the hypertensive cohort only women with hyperhomocysteinemia showed increased cardiovascular mortality. CONCLUSION: Hyperhomocysteinemia is common in high-risk women and adversely affects their prognosis, although it is unrelated to the CAD atherosclerotic burden.

Expression of telomerase (hTERT) in aldosterone-producing adrenocortical tumors.

Telomerase was found in cancers and immortalized cell lines, but only occasionally in normal tissues, thus suggesting that measurement of its hTERT subunit might help distinguishing benign from malignant tumors. Data on hTERT expression in adrenocortical tumors are scant and mostly confined to non-functioning tumors. Therefore, we investigated whether hTERT expression may predict malignancy in aldosterone producing adrenocortical tumors. We measured hTERT mRNA with a real-time one-step reverse transcription (RT) polymerase chain reaction (PCR) method, based on the use of hTERT-specific fluorescence resonance energy transfer (FRET) probes, in 19 adrenalectomized patients with aldosterone-producing adenomas (APAs), in whom long-term follow-up (median 7 years, range 5-14 years) data were available. We also studied two rare aldosterone-producing carcinomas (APCs), eight adrenocortical carcinomas (ACs), twelve normal adrenal cortexes, and two malignant cell lines (NCI-295H and SW-13). Telomerase activity and hTERT immunoreactivity were also investigated. Of interest, we detected hTERT mRNA in 58% of APAs at levels similar to those of malignant tumors, which all consistently showed hTERT expression. In hTERT expressing tumors, immunocytochemistry showed the nuclear expression of hTERT. No hTERT expression was found in the normal adrenocortical tissue. No histopathology differences were observed between hTERT-positive and -negative APAs; however, a patient originally held to have an hTERT-positive APA was retrospectively classified as APC because of metastatic spread. In conclusion, RT-PCR measurement of hTERT mRNA is a hallmark of malignant adrenocortical tumors, but identifies also a subset of hTERT-expressing APAs that might show metastatic spread at long-term follow-up.

Is homocysteine important as risk factor for coronary heart disease?

AIM: Homocysteine (Hcy), a sulfur-containing amino acid product of methionine metabolism, may play an important role in the development of cardiovascular disease. In this paper we review available knowledge on the pathways leading to synthesis and degradation of Hcy, as well as on the genetic and environmental factors affecting its plasma levels, focussing on its potential role in the development of coronary heart disease. DATA SYNTHESIS: Hyperhomocysteinemia (HHcy) is determined by genetic and environmental factors and represents a modifiable cardiovascular risk factor since vitamin supplementation has been shown to effectively lower plasma homocysteine levels. While case-control and cross-sectional studies consistently showed an association of HHcy with cardiovascular disease, prospective studies have given conflicting results. Thus, the role of HHcy in the development of coronary heart disease is still under debate. Furthermore, it remains unclear which patients should be screened for HHcy and treated to correct HHcy. CONCLUSIONS: Available information collectively suggests that although HHcy can be regarded as a minor risk factor for coronary heart disease, it interacts with other risk factors in triggering new events in patients with known CAD. Thus, the treatment of mild HHcy with folate supplementation is appropriate in particular in high risk patients or patients with established CAD who do not present with the "traditional" risk factors.

Hyperhomocysteinemia is inversely related with left ventricular ejection fraction and predicts cardiovascular mortality in high-risk coronary artery disease hypertensives.

OBJECTIVE: The purpose of this study was to investigate the relationship of plasma homocysteine (tHcy) levels with coronary artery disease (CAD) and left ventricular ejection fraction (LVEF) in high-risk patients undergoing coronary angiography for suspected CAD. METHODS AND RESULTS: In 936 consecutive patients, we measured LVEF, tHcy, folate levels, and quantified CAD with a modified Duke Index score. We also genotyped patients at the methylen-tetrahydrofolate-reductase 677C-->T polymorphism. Hyperhomocysteinemia (HHcy) was defined as tHcy levels > or =15.46 micromol/L; total and cardiovascular mortality was assessed at follow-up that lasted 43 months (median). CAD was confirmed in 75% of patients and ruled out in the rest (non-CAD group). No relationship of HHcy with either arterial hypertension or the CAD score was found. In contrast, there was a significant inverse relationship of tHcy with LVEF in arterial hypertensive but not in normotensive patients, regardless of previous myocardial infarction. At logistic regression, HHcy was the strongest predictor (P=0.001) of a low (<40%) LVEF, followed by type 2 diabetes mellitus and cigarette smoking. At follow-up, HHcy significantly predicted cardiovascular mortality but only in the arterial hypertension subgroup. CONCLUSIONS: In arterial hypertensive but not in normotensive patients, HHcy predicts cardiovascular mortality and a low LVEF, independent of CAD and history of myocardial infarction.

Bradykinin and matrix metalloproteinases are involved the structural alterations of rat small resistance arteries with inhibition of ACE and NEP.

BACKGROUND AND AIM: Increased vascular resistance is a hallmark of hypertension and involves structural alterations, which may entail smooth muscle cell hypertrophy or hyperplasia, or qualitative or quantitative changes in extracellular matrix (ECM) proteins. Since the renin-angiotensin-aldosterone system modulates these changes, we investigated the effects of 8 weeks of treatment with an angiotensin-converting enzyme (ACE) inhibitor, ramipril (RAM), or a dual ACE and neutral endopeptidase (NEP) inhibitor, MDL-100240 (MDL), on mesenteric small artery structure and ECM proteins in mRen2-transgenic rats (TGRs), an animal model of hypertension with severe cardiovascular damage. MATERIALS AND METHODS: Thirty-five 5-week-old rats were included in the study: six TGRs received RAM; five TGRs RAM + the bradykinin receptor inhibitor, icatibant; six TGRs, MDL; and five TGRs MDL + icatibant, while eight TGRs and five normotensive Sprague-Dawley controls were kept untreated. Mesenteric small arteries were dissected and mounted on a micromyograph. The media-to-lumen ratio (M/L) was then calculated. Vascular metalloproteinase (MMP) content was evaluated by zymography. RESULTS: In untreated TGRs severe hypertension was associated with inward eutrophic remodelling of small arteries. Both RAM and MDL prevented the increase in blood pressure and M/L and decreased MMPs. Icatibant blunted the effect of MDL on BP, M/L and MMPs. CONCLUSIONS: Changes in collagenase activity induced by ramipril and MDL are associated with prevention of small artery structural alterations in TGRs. Furthermore, MDL-induced enhancement of bradykinin could play a role in both the prevention of vascular structural alterations and in the stimulation of MMPs.