Effects of vascular risk factors on balance assessed by computerized posturography in the elderly.

AIMS: The purpose of this study was to evaluate the effects of vascular risk factors, isolated or in association, on balance, as assessed by posturographic platform. METHODS: One hundred and seven elderly subjects (mean age 73.8+/-5.8), with no cognitive impairment (MMSE>24), able to perform self-care activities and to walk independently for at least 400 meters, free from major diseases. Subjective complaints were assessed by means of the Sickness Impact Profile Questionnaire. The following cardiovascular risk factors were considered: hypercholesterolemia, smoking, hypertension, glucose intolerance, and obesity. Balance tests were performed in three standardized positions (side-by-side, semi-tandem, tandem) on a vertical force platform, from which center of foot pressure positions and displacements were recorded. RESULTS: A large percentage of enrolled subjects (35.5%) complained of unsteadiness, dizziness or vertigo, but only a few (24=22.4%) reported at least one fall in the 6 months before enrolment in the study. Among the cardiovascular risk factors taken into account, only glucose intolerance and, to a lesser extent, obesity, were associated with worse performance in stabilometric tests, independent of age and sex. Subjects with 3 or more risk factors, compared with those with 2 or less showed worse performance in medio-lateral sway (p=0.001), track length (p=0.05) and elliptical area (p=0.005), in tandem position. CONCLUSIONS: The cumulative presence of cardiovascular risk factors may contribute to impairment of balance in the elderly. This effect may be due to subclinical damage of that part of the nervous system controlling balance.

Effects of hypertension on balance assessed by computerized posturography in the elderly.

Unsteadiness, dizziness and vertigo occur more frequently in hypertensive subjects, compared to the normal ones. This study evaluated the influence of hypertension on balance tests, performed on posturographic platform. The study pool consisted of 112 persons aged 65 and older (65 hypertensives), their mean age was 72.9+/-0.5, scored on the Mini Mental State Examination (MMSE) greater than 24, were able to perform self-care activities, to walk independently for at least 400 m and were free from major diseases. Subjective dizziness and vertigo were assessed by means of Sickness-Impact-Profile-Questionnaire (SIPQ). The static posturographic tests were performed on a vertical force platform, from which the center of foot pressure (COP) positions and displacements were recorded. In balance tests three standardized positions were utilized: feet 30 degrees apart, semitandem and tandem. Subjects with hypertension complained more frequently dizziness and vertigo (41.5% vs. 21.3%). The track-length and COP-velocity were associated with age in all the balance tests. In semitandem and tandem positions, the medio-lateral sway distance significantly increased in elderly subjects compared to young controls. No difference, however, was found in balance tests between normotensive and hypertensive subjects. Those with uncomplicated hypertension compared with normo-tensive subjects, although complaining more frequently symptoms of postural instability, did not show worse performances in static posturographic tests.

Prostaglandin E synthases in zebrafish.

OBJECTIVE: Prostaglandin E synthases (PGESs) are being explored as antiinflammatory drug targets as alternatives to cyclooxygenase (COX)-2. Located downstream of the cyclooxygenases, PGESs catalyze PGE(2) formation, and deletion of microsomal (m)-PGES-1 abrogates inflammation. We sought to characterize the developmental expression of COX and PGES in zebrafish. METHODS AND RESULTS: We cloned zebrafish cytosolic (c) and m-PGES orthologs and mapped them to syntenic regions of chromosomes 23 and 5. cPGES was widely expressed during development and was coordinately regulated with zCOX-1 in the inner ear, the pronephros, and intestine. COX-2 and mPGES-1 exhibited restricted expression, dominantly in the vasculature of the aortic arch. However, the enzymes were anatomically segregated within the vessel wall. Experiments with antisense morpholinos and with nonsteroidal antiinflammatory drugs suggest that these genes may not be critical for development. CONCLUSIONS: mPGES-1 is developmentally coregulated with COX-2 in vasculature. Given the high fecundidity and translucency of the zebrafish, this model may afford a high throughput system for characterization of novel PGES inhibitors. Microsomal prostaglandin E synthase (mPGES)-1, located downstream of COX-2, may represent a novel antiinflammatory drug target. Zebrafish cytosolic (c) PGES-1 and COX-1 were coordinately expressed; mPGES-1 and COX-2 were expressed particularly in the vasculature. Zebrafish may afford a high throughput system for detection of novel PGES inhibitors.

Increased expression of transforming growth factor-beta1 as a stabilizing factor in human atherosclerotic plaques.

BACKGROUND AND PURPOSE: Transforming growth factor-beta (TGF-beta) is a growth factor/cytokine involved in vascular remodeling and atherogenesis. Recent studies in apolipoprotein E-deficient mice have demonstrated a pivotal role of TGF-beta in the maintenance of the balance between inflammation and fibrosis in atherosclerotic plaques. Furthermore, inhibition of TGF-beta signaling has been shown to accelerate plaque formation and its progression toward an unstable phenotype in mice. However, if this mechanism is operative also in humans is still unknown. The aim of this study was to characterize the expression of TGF-beta1 in human carotid plaque and to correlate it with the extent of inflammatory infiltration and collagen content with the clinical signs of plaque instability. METHODS: Plaques were obtained from patients undergoing carotid endoarterectomy and divided into symptomatic and asymptomatic according to clinical evidence of recent transient ischemic attack or stroke. Plaques were analyzed for TGF-beta1 expression by Immunocytochemistry, Western, and Northern blotting analysis. Immunocytochemistry was used to identify CD68+ macrophages, CD3 T lymphocytes, HLA-DR+ cells, and alpha-smooth muscle cells. Procollagen and interstitial collagen content were analyzed by immunohistochemistry and Sirius Red staining, respectively. RESULTS: Plaque TGF-beta1 mRNA was increased up to 3-fold in asymptomatic as compared with symptomatic plaques. Plaques from asymptomatic group had fewer (P<0.0001) macrophages and T lymphocytes compared with symptomatic plaques. TGF-beta1 gene was transcriptionally active as demonstrated by increased (P<0.0001) TGF-beta1 protein expression in asymptomatic plaques. Immunohistochemistry showed that TGF-beta was mainly expressed in plaque shoulder and was associated with a comparable increase (P<0.0001) in plaque procollagen and collagen content. CONCLUSIONS: In conclusion, this study demonstrates the higher expression of TGF-beta1 in human asymptomatic lesions and provides evidence that TGF-beta1 may play an important role in the process of plaque stabilization.

A polymorphism in the cyclooxygenase 2 gene as an inherited protective factor against myocardial infarction and stroke.

CONTEXT: Myocardial infarction (MI) and ischemic stroke are thought to be caused by matrix digestion by metalloproteinases (MMPs) leading to rupture of atherosclerotic plaques. Production of macrophage MMP-2 and MMP-9 is induced by cyclooxygenase 2 (COX-2) and prostaglandin E(2) synthesis. Although COX-2 expression may be genetically determined, the relation between COX-2 polymorphisms and the risk of MI and stroke is unclear. OBJECTIVE: To investigate the relationship between the -765G-->C polymorphism of the COX-2 gene and clinically evident plaque rupture. DESIGN, SETTING, AND PARTICIPANTS: Prospective, matched case-control study conducted between March 2002 and October 2003 among 864 patients with first MI or atherothrombotic ischemic stroke and 864 hospitalized controls. The groups were matched for age, sex, body mass index, smoking, hypertension, hypercholesterolemia, and diabetes. The -765G-->C variant of the COX-2 gene was genotyped by restriction endonuclease digestion of polymerase chain reaction products. MAIN OUTCOME MEASURES: Presence of the -765G-->C polymorphism of the COX-2 gene; COX-2, MMP-2, and MMP-9 expression and activity in plaques and in peripheral monocytes; urinary 6-keto PGF1alpha (marker of endothelial prostacyclin); and endothelium-dependent and -independent forearm blood flow vasodilation. RESULTS: The prevalence of -765GC was 2.41 times higher among controls than among cases (43.3% vs 17.9%; P<.001). The prevalence of -765CC homozygosity was 5.81 times higher (6.4% vs 1.1%; P =.04). Among participants carrying the -765GC and -765CC genotypes, the prevalence ratios for MI or stroke were 0.48 (95% CI, 0.36-0.68) and 0.33 (95% CI, 0.24-0.55), respectively. Expression of COX-2 and MMPs was significantly lower in atherosclerotic plaques from participants carrying the -765C allele, while the -765G-->C polymorphism did not affect endothelial prostacyclin biosynthesis or endothelium-dependent vasodilation in vivo. In subgroup analyses (n = 224 cases), serum high-sensitivity C-reactive protein was significantly lower in patients carrying the -765C allele (mean [SD], 0.78 [0.1] vs 2.56 [0.4] mg/L; P =.04). CONCLUSIONS: We found that the -765G-->C polymorphism of the COX-2 gene is associated with a decreased risk of MI and stroke. Detection of this genotype may be useful for predicting genetic risk of MI and stroke.

Balance between PGD synthase and PGE synthase is a major determinant of atherosclerotic plaque instability in humans.

OBJECTIVE: Inducible cyclooxygenase (COX-2) catalyzes the first step in prostanoid biosynthesis and is considered a proinflammatory enzyme. COX-2 and type 1 inducible PGE synthase (mPGES-1) have a role in metalloproteinase (MMP) release leading to plaque rupture. In contrast, lipocalin-type PGD synthase (L-PGDS) has been shown to exert antiinflammatory actions. Thus, in this study we investigated whether a shift from a PGDS-oriented to a PGES-oriented profile in arachidonate metabolism leads to inflammatory activation in rupture-prone plaque macrophages. METHODS AND RESULTS: Atherosclerotic plaques were obtained from 60 patients who underwent carotid endarterectomy, symptomatic (n=30) and asymptomatic (n=30) according to evidence of recent transient ischemic attack or stroke. Plaques were analyzed for COX-2, mPGES-1, L-PGDS, PPARgamma, IkappaBalpha, NF-kappaB, and MMP-9 by immunocytochemistry, Western blot, reverse-transcriptase polymerase chain reaction, enzyme immunoassay, and zymography. Prostaglandin E2 (PGE2) pathway was significantly prevalent in symptomatic plaques, whereas PGD2 pathway was overexpressed in asymptomatic ones, associated with NF-kappaB inactivation and MMP-9 suppression. In vitro COX-2 inhibition in monocytes was associated with reduced MMP-9 release only when PGD2 pathway overcame PGE2 pathway. CONCLUSIONS: These results suggest that COX-2 may have proinflammatory and antiinflammatory properties as a function of expression of downstream PGH2 isomerases, and that the switch from L-PGDS to mPGES-1 in plaque macrophages is associated with cerebral ischemic syndromes, possibly through MMP-induced plaque rupture.

Blockade of the angiotensin II type 1 receptor stabilizes atherosclerotic plaques in humans by inhibiting prostaglandin E2-dependent matrix metalloproteinase activity.

BACKGROUND: Clinical trials have demonstrated that agents that inhibit the angiotensin II pathway confer benefit beyond the reduction of blood pressure alone. However, the molecular mechanism underlying this effect has yet to be investigated. Recently, we have demonstrated enhanced expression of inducible cyclooxygenase (COX) and prostaglandin (PG)E2-dependent synthase (COX-2/mPGES-1) in human symptomatic plaques and provided evidence that it is associated with metalloproteinase (MMP)-induced plaque rupture. Thus, the aim of this study was to characterize the effect of the angiotensin II type 1 (AT1) receptor antagonist irbesartan on the inflammatory infiltration and expression of COX-2/mPGES-1 and MMPs in human carotid plaques. METHODS AND RESULTS: Seventy patients with symptomatic carotid artery stenosis were randomized to irbesartan (300 mg/d) or chlorthalidone (50 mg/d) for 4 months before endarterectomy. Plaques were subjected to analysis of COX-1, COX-2, mPGES-1, MMP-2, and MMP-9, angiotensin II, AT(1), AT2, and collagen content by immunocytochemistry, Western blot, and reverse-transcriptase polymerase chain reaction, whereas zymography was used to detect MMP activity. Immunohistochemistry was also used to identify CD68+ macrophages, CD3+ T lymphocytes, smooth muscle cells (SMCs), and HLA-DR+ inflammatory cells. Plaques from the irbesartan group had fewer (P<0.0001) macrophages, T lymphocytes, and HLA-DR+ cells; less (P<0.0001) immunoreactivity for COX-2/mPGES-1 and MMPs; reduced (P<0.0001) gelatinolytic activity; and increased (P<0.0001) collagen content. It is worth noting that COX-2/mPGES-1 inhibition was observed after incubation in vitro with irbesartan but not with the selective AT2 blockade PD123,319. CONCLUSIONS: This study demonstrates that irbesartan decreases inflammation and inhibits COX-2/mPGES-1 expression in plaque macrophages, and this effect may in turn contribute to plaque stabilization by inhibition of MMP-induced plaque rupture.

Preprocedural level of soluble CD40L is predictive of enhanced inflammatory response and restenosis after coronary angioplasty.

BACKGROUND: Inflammation plays a pathogenic role in the development of restenosis after percutaneous transluminal coronary angioplasty (PTCA). CD40-CD40L interaction is involved in the pathogenesis of atherosclerosis; however, its role in the pathophysiology of restenosis is still unclear. We tested the hypothesis that soluble CD40L (sCD40L) may be involved in the process of restenosis and that it exerts its effect by triggering a complex group of inflammatory reactions on endothelial and mononuclear cells. METHODS AND RESULTS: We studied 70 patients who underwent PTCA and who had repeated angiograms at 6-month follow-up. Plasma sCD40L was measured before and 1, 5, 15, and 180 days after PTCA, whereas plasma soluble intercellular adhesion molecule-1, soluble vascular cell adhesion molecule-1, E-selectin, and monocyte chemoattractant protein (MCP)-1 were measured before and 24 hours after PTCA. Furthermore, the release of adhesion molecules and MCP-1 and the ability to repair an injury in endothelial cells, as well as the generation of O2- in monocytes, were analyzed in vitro after stimulation with serum from patients or healthy control subjects. Restenosis occurred in 18 patients (26%). Restenotic patients had preprocedural sCD40L significantly higher than patients with favorable outcomes (2.13+/-0.3 versus 0.87+/-0.12 ng/mL, P<0.0001). Elevated sCD40L at baseline was significantly correlated with adhesion molecules and MCP-1 generation after PTCA and with lumen loss at 6-month follow-up. Furthermore, high sCD40L was directly associated in vitro with adhesion molecules and MCP-1 generation and impaired migration in endothelial cells and with enhanced O2- generation in monocytes. CONCLUSIONS: We conclude that increased sCD40L is associated with late restenosis after PTCA. This may provide an important biochemical link between restenosis and aspirin-insensitive platelet activation. These results provide a rationale for studies with new antiplatelet treatments in patients who underwent PTCA.

The receptor RAGE as a progression factor amplifying arachidonate-dependent inflammatory and proteolytic response in human atherosclerotic plaques: role of glycemic control.

BACKGROUND: RAGE (receptor for advanced glycation end products [AGEs]) plays a role in diabetic atherosclerosis. Recently, we have demonstrated enhanced expression of cyclooxygenase-2 and PGE synthase-1 (COX-2/mPGES-1) in human symptomatic plaques, and provided evidence that it is associated with metalloproteinase (MMP)-induced plaque rupture. However, the specific transmembrane signaling pathway(s) influencing plaque COX-2/mPGES-1 expression is unknown. The aim of this study was to characterize RAGE expression in human plaques and to correlate it with the inflammatory infiltration, COX-2/mPGES-1 and MMP expression, and with clinical evidence of diabetes. METHODS AND RESULTS: Plaques obtained from 60 patients undergoing carotid endarterectomy were divided into diabetic and nondiabetic according to clinical evidence of type 2 diabetes. Plaques were subjected to analysis of RAGE, NF-kappaB, COX-2/mPGES-1, MMP-2 and MMP-9, lipid and oxidized LDL (oxLDL) content, and collagen content by immunohistochemistry and Western blot, whereas zymography was used to detect MMP activity. Immunohistochemistry was used to identify CD68+ macrophages, CD3+ T-lymphocytes, smooth muscle cells (SMCs), and HLA-DR+ inflammatory cells. Diabetic plaques had more (P<0.0001) macrophages, T-lymphocytes, and HLA-DR+ cells, more (P<0.0001) immunoreactivity for RAGE, activated NF-kappaB, COX-2/mPGES-1, and MMPs, increased (P<0.0001) gelatinolytic activity, reduced (P<0.0001) collagen content, and increased (P<0.0001) lipid and oxLDL content. Interestingly, RAGE, COX-2/mPGES-1, and MMP expression was linearly correlated with plasma level of HbA1c. CONCLUSIONS: In conclusion, this study demonstrates in humans that RAGE overexpression is associated with enhanced inflammatory reaction and COX-2/mPGES-1 expression in diabetic plaque macrophages, and this effect may contribute to plaque destabilization by inducing culprit metalloproteinase expression.

Suppression of the functionally coupled cyclooxygenase-2/prostaglandin E synthase as a basis of simvastatin-dependent plaque stabilization in humans.

BACKGROUND: The clinical benefits of statins are attributed to changes in plaque composition that lead to reduced metalloproteinase (MMP) activity and plaque stabilization. However, the molecular mechanism of this effect is unclear. Recently, we demonstrated enhanced expression of isoforms of inducible cyclooxygenase (COX) and PGE synthase (COX-2/mPGES) in human symptomatic plaque and provided evidence that this is associated with MMP-induced plaque rupture. The aim of this study was to characterize the effect of simvastatin on inflammatory infiltration and the expression of COX-2/mPGES and MMPs in human carotid plaques. METHODS AND RESULTS: Seventy patients with symptomatic carotid artery stenosis were randomized to the American Heart Association Step 1 diet plus simvastatin (40 mg/d) or the American Heart Association Step 1 diet alone for 4 months before endarterectomy. Plaques were subjected to analysis of COX-1, COX-2, mPGES, MMP-2 and MMP-9, lipid and oxidized LDL (oxLDL) content, and collagen content by immunocytochemistry, Western blot, and reverse transcription-polymerase chain reaction, whereas zymography was used to detect MMP activity. Immunocytochemistry was also used to identify CD68+ macrophages, CD3+ T-lymphocytes, smooth muscle cells (SMCs), and HLA-DR+ inflammatory cells. Plaques from the simvastatin group had fewer (P<0.0001) macrophages, T-lymphocytes, and HLA-DR+ cells; less (P<0.0001) immunoreactivity for COX-2/mPGES and MMPs; reduced (P<0.0001) gelatinolytic activity; increased (P<0.0001) collagen content; and reduced (P<0.0001) lipid and oxLDL content. Interestingly, COX-2/mPGES inhibition by simvastatin was completely reversed by mevalonate in vitro. CONCLUSIONS: This study demonstrates that simvastatin decreases inflammation and inhibits COX-2/mPGES expression in plaque macrophages, and this effect in turn may contribute to plaque stabilization by inhibition of MMP-induced plaque rupture.