Hyperhomocysteinemia is an independent risk factor of atherosclerosis in patients with metabolic syndrome.

BACKGROUND: Metabolic syndrome (MetS) is a clinical condition potentially promoting the development of atherosclerotic disease. To date, the clinical impact of elevated serum homocysteine (Hcy) levels in MetS is still under discussion. The aim of this cross sectional study was to evaluate the relationship between MetS and hyperhomocysteinemia and the potential role of Hcy in the pathogenesis of atherosclerotic complications of MetS. METHODS: We recruited 300 outpatients with MetS. All patients underwent a medical history collection, physical examination, blood sampling and carotid ultrasound echo-color Doppler. According to Hcy levels, MetS patients were divided into two groups: "normal" (< 10.7 µmol/l; n = 140, group 1) and "high" Hcy (≥ 10.7 µmol/l; n = 160, group 2). Comparisons between groups were made by Student's t-test or Chi-square test. The effects of potential covariates on group differences were evaluated by general linear models. The relationships between continuous variables were assessed by simple or multiple correlation and by linear regression. Multiple regression models were built to evaluate the effects of Hcy, together with other potential risk factors, on carotid atherosclerosis. RESULTS: Patients with high Hcy were predominantly male and slightly older than group 1 patients. Smokers and non-smokers exhibited similar Hcy levels, nor was a statistical relationship between pack-years and Hcy observed. Group 2 showed lower levels of folic acid, vitamin D, high density lipoprotein (HDL)-cholesterol and glomerular filtration rate (e-GFR) than group 1, but higher levels of C-peptide, uric acid and triglycerides. In all patients, Hcy was positively correlated with C-peptide and uric acid and negatively with folic acid and e-GFR. Intima-media thickness (IMT) and carotid stenosis degree were significantly higher in patients with high Hcy and a positive relationship between Hcy and both IMT and carotid stenosis was detected in all patients. Finally, Hcy atherogenic effects were independent of other well-known atherosclerosis risk factors. CONCLUSIONS: Our results highlight a link between MetS and hyperhomocysteinemia and a direct effect of Hcy on atherogenic process during MetS. Early correction of folic acid levels may contribute to prevent cardiovascular complications in MetS patients.

Metabolic syndrome and Chronic Obstructive Pulmonary Disease (COPD): The interplay among smoking, insulin resistance and vitamin D.

BACKGROUND: A close relationship between Metabolic Syndrome (MetS) and Chronic Obstructive Pulmonary Disease (COPD) has been described, but the exact nature of this link remains unclear. Current epidemiological data refer exclusively to the MetS prevalence among patients with COPD and data about the prevalence of COPD in MetS patients are still unavailable. AIM OF THE STUDY: To analyse and compare risk factors, clinical and metabolic characteristics, as well as the main respiratory function parameters, among patients affected by MetS, COPD or both diseases. PATIENTS: We recruited 59 outpatients with MetS and 76 outpatients with COPD. After medical history collection, physical examination, blood sampling for routine analysis, spirometric evaluation, they were subdivided into MetS (n = 46), MetS+COPD (n = 60), COPD (n = 29). RESULTS: A MetS diagnosis was assigned to 62% of COPD patients recruited in the COPD Outpatients Clinic of the Pneumology Department, while the COPD prevalence in MetS patients enrolled in the Internal Medicine Metabolic Disorders Outpatients Clinic was 22%. More than 60% of subjects enrolled in each Department were unaware that they suffered from an additional disease. MetS+COPD patients exhibited significantly higher C-peptide levels. We also found a positive relation between C-peptide and pack-years in all subjects and a negative correlation between C-peptide and vitamin D only in current smokers. Finally, a negative association emerged between smoking and vitamin D. CONCLUSIONS: We have estimated, for the first time, the COPD prevalence in MetS and suggest a potential role of smoking in inducing insulin resistance. Moreover, a direct effect of smoking on vitamin D levels is proposed as a novel mechanism, which may account for both insulin resistance and COPD development.

Protection of human endothelial cells from oxidative stress: role of Ras-ERK1/2 signaling.

BACKGROUND: Reactive oxygen species play a critical role in inducing apoptosis. The small GTPase p21 Ras and the ERK1/2 MAPK have been proposed as key regulators of the signaling cascade triggered by oxidative stress (H2O2). Harvey-Ras (Ha-Ras) and Kirsten-Ras (Ki-Ras) isoforms are so far functionally indistinguishable, because they activate the same downstream effectors, including ERK1/2. Moreover, ERK1/2 signaling has been involved in both protection and induction of apoptosis. METHODS AND RESULTS: Human umbilical vein endothelial cells (HUVECs) were subjected to H2O2, and apoptosis was detected by fluorescence-activated cell sorting analysis, fluorescence microscopy, and caspase-3 activation. Transfection of Ha-Ras and Ki-Ras genes in HUVECs was performed to evaluate the response to H2O2. We have found that, whereas Ha-Ras decreases tolerance to oxidative stress, Ki-Ras has a potent antiapoptotic activity. Both effects are mediated by ERK1/2. Tolerance to H2O2 is encoded by a unique stretch of lysines at the COOH terminus of the Ki-Ras, lacking in Ha-Ras, and it is relatively independent of the farnesylated anchor. Inhibition of p21 Ras signaling by farnesylation inhibitors increased the resistance to apoptosis in Ha-Ras-expressing cells. CONCLUSIONS: These findings explain the opposite effects of ERK1/2 stimulation on apoptosis found in different cell types and suggest that local activation of ERK1/2 signaling may account for the opposing response to oxidative stress by Ha-Ras or Ki-Ras-expressing cells. Modulation of cell reactivity to oxidative stress by p21 Ras points to the specific and predictive effects of Ras inhibitors in vivo as potential therapeutic drugs in disorders produced by increase of reactive oxygen species inside the cells.

Weight loss in combination with physical activity improves endothelial dysfunction in human obesity.

OBJECTIVE: To test whether weight loss may improve endothelial dysfunction in human obesity, we recruited 28 healthy obese subjects, aged 30-46 years, with BMI 30-43 kg/m(2). RESEARCH DESIGN AND METHODS: Endothelium-dependent and -independent vasodilation were investigated by intra-arterial infusion of increasing doses of acetylcholine (ACh; 7.5, 15, and 30 microg x ml(-1) x min(-1)) and sodium nitroprusside (0.8, 1.6, and 3.2 microg x ml(-1) x min(-1)). Insulin resistance was estimated by homeostasis model assessment (HOMA). Weight loss was obtained by caloric restriction and physical activity. RESULTS: We observed a significant reduction in BMI (from 33.1 +/- 4.2 to 27.5 +/- 4.5 kg/m(2), -16.9%, P < 0.0001) and in waist circumference (from 108.2 +/- 12.1 to 96.8 +/- 12.9 cm, -10.5%, P < 0.0001). Weight loss was also associated with a significant increase in ACh-stimulated forearm blood flow (FBF), from 7.4 +/- 2.8 to 12.9 +/- 3.4 ml. 100 ml(-1) of tissue x min(-1) kg/m(2) (P < 0.0001). Multivariate regression analysis demonstrated that the only independent predictor of FBF was HOMA, accounting for 44.5% of the variation, whereas the addition of BMI explained another 2.3% of the variation. CONCLUSIONS: Our data demonstrate that energy-restricted diet associated with physical activity induce a significant and clinically relevant improvement in ACh-stimulated vasodilation in obese healthy subjects.

Transient cerebral ischemia in an elderly patient with patent foramen ovale and atrial septal aneurysm.

Cerebrovascular disease is one of the most common causes of cerebrovascular morbidity and mortality in developed countries; up to 40% of acute ischemic strokes in young adults are cryptogenic in nature - that is, no cause is determined. However, in more than half of these patients, patent foramen ovale (PFO) is seen along with an increased incidence of atrial septal aneurysm (ASA). The following is a report of an interesting case: a 68-year-old man with ASA and transient cerebral ischemia. Transesophageal echocardiography (TEE) showed the presence of ASA; a test with microbubbles derived from a mixture of air and saline or colloids pointed out a shunt on the foramen ovale following Valsalva's maneuver. The patient underwent percutaneous transcatheter closure of the interatrial communication by an interventional cardiologist. TEE and transcranial Doppler or TEE with the microbubbles test are the recommended methods for detecting and quantifying intracardiac shunts, both at rest and following Valsalva's maneuver. In patients following the first event of transient ischemic attack, and without clinical and anatomical risk factors (such as the presence of ASA, PFO, and basal shunt), pharmacological treatment with antiplatelets or anticoagulants is closely recommended. On the contrary, in patients following the first event of transient ischemic attack, or a recurrent event during antiplatelet treatment, the percutaneous closure of PFO is recommended.