Mononuclear cell adhesion to collagen ex vivo is related to pulse pressure in elderly subjects

C-reactive protein in hypertension: clinical significance and predictive value

Mild elevations in C-reactive protein concentration predict myocardial infarction, stroke, and vascular death in a variety of clinical settings. Despite the lack of specific evidence that C-reactive protein levels are independently associated with cardiovascular risk in patients with hypertension, the prognostic value of C-reactive protein has proven to be complementary to that of blood pressure values. Recent epidemiological evidence has indicated a link between hypertension and increased C-reactive protein levels, and there are some indications that C-reactive protein may predict the future development of hypertension. Vessel wall inflammation is part of the vascular changes observed in animal models of hypertension. C-reactive protein is involved in the complex pathways leading to endothelial dysfunction, increased peripheral vascular resistance, and large artery stiffness in hypertension. In this regard, the role of C-reactive protein as a marker or a causal factor in promoting hypertension and its complications remains, however, to be elucidated. In this review, various aspects of the pathogenesis of inflammation in hypertension are summarized and connected with clinical studies that address the role of C-reactive protein in hypertensive disease.

Assessment of arterial ventricular coupling changes in patients under therapy with various antihypertensive agents by a non-invasive echocardiographic method

BACKGROUND

The integration between arterial and ventricular function has been studied by mostly invasive techniques. We considered assessing the influence of various antihypertensive medications on arterial-ventricular coupling (AVC) with the use of a non-invasive echocardiographic method.

METHODS

A total of 9037 patients, who had been under treatment for essential arterial hypertension were studied echocardiographically at baseline prior to therapy and after 6 months of antihypertensive monotherapy (diuretics, beta-blockers without intrinsic sympathomimetic activity (ISA), beta-blockers with ISA, a-blockers, angiotensin converting enzyme inhibitors (ACEI), angiotensin II receptor blockers (AIIRA), non-dihydropyridine calcium antagonists, and dihydropyridine calcium antagonists). The AVC was calculated by echocardiographic measurements based on the equation: AVC=ESV/SV (ESV, end systolic volume; SV, stroke volume).

RESULTS

ACEI, AIIRA, and dihydropyridine calcium antagonists decreased (P<0.0001 for all) while diuretics, alpha-blockers, both beta-blocker groups, and non-dihydropyridines increased significantly the AVC values compared to baseline measurements (P<0.0001 for all, except P=0.02 for alpha-blockers). Changes in AVC were the most highly correlated with changes in EF (r=-0.979, P<0.0001).

CONCLUSION

Various antihypertensive drugs have a differential effect on AVC with ACEI, AIIRA, and dihydropyridine calcium antagonists having the most favorable effect on this index. AVC provides a meaningful index of cardiovascular performance in hypertension and offers the possibility of wide employment and serial follow-up in large numbers of patients because of its completely non-invasive nature.

Soluble cell adhesion molecules in hypertensive concentric left ventricular hypertrophy

OBJECTIVE

Concentric left ventricular (LV) hypertrophy is an important cardiovascular risk factor. We investigated whether concentric LV hypertrophy is associated with activation of the vascular endothelium, as assessed by measurements of soluble cell adhesion molecules.

DESIGN

E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular adhesion molecule-1 (VCAM-1) were measured in serum from hypertensive patients with LV hypertrophy (64 with concentric and 47 with eccentric hypertrophy) and from two matched control groups consisting of 38 hypertensive patients without LV hypertrophy and 38 normotensive subjects. Carotid artery intima-media thickness (IMT) was examined by ultrasonography and LV mass by echocardiography. Neurohormone activities of the renin-angiotensin-aldosterone system were also measured.

RESULTS

E-selectin levels were higher in hypertensive than in normotensive subjects (56 +/- 19 versus 49 +/- 11 ng/ml, P = 0.031). Patients with concentric LV hypertrophy had higher levels of E-selectin (61 +/- 21 versus 49 +/- 15 ng/ml, P < 0.001), ICAM-1 (273 +/- 49 versus 254 +/- 49 ng/ml, P = 0.043), VCAM-1 (591 +/- 131 versus 544 +/- 78 ng/ml, P = 0.038) and greater carotid artery IMT (0.99 +/- 0.26 versus 0.83 +/- 0.15 mm, P = 0.018) than eccentric LV hypertrophy patients. E-selectin and VCAM-1 correlated positively to LV relative wall thickness (P = 0.040 and 0.037, respectively), with a similar trend for ICAM-1 (P = 0.083). E-selectin correlated with serum aldosterone (P < 0.001), and E-selectin and ICAM-1 with plasma angiotensin converting enzyme activity (P = 0.003 and 0.036, respectively).

CONCLUSION

Increased levels of soluble cell adhesion molecules and an increased carotid artery IMT characterize concentric LV hypertrophy. This indicates perturbations at the vascular level, involving activation of the vascular endothelium in hypertensive patients with concentric LV hypertrophy.

Association between pulse pressure and C-reactive protein among apparently healthy US adults

Elevated pulse pressure has been associated with an increased risk of cardiovascular disease, which is increasingly being seen as an inflammatory disease. Thus, the mechanism underlying the link between elevated pulse pressure and cardiovascular disease risk may be inflammation. However, investigators have not examined the relationship between pulse pressure and C-reactive protein, an inflammation marker that has been closely linked to cardiovascular risk. We examined the cross-sectional relationship between pulse pressure and C-reactive protein among 9867 healthy persons 17 years of age or older who participated in the Third National Health and Nutrition Examination Survey. The association between pulse pressure and the odds of having an elevated C-reactive protein level (> or = 0.66 mg/dL) was assessed by logistic regression. In a model that adjusted for systolic blood pressure, demographic factors, cholesterol, measures of obesity, smoking, alcohol consumption, physical activity, and antihypertensive medication use, a 10 mm Hg increase in pulse pressure was associated with a 15% increase in the odds of having an elevated C-reactive protein level (odds ratio, 1.15; 95% confidence interval, 1.01 to 1.31; P=0.04). When the same model was re-run adjusting for diastolic blood pressure instead of systolic blood pressure, a 10 mm Hg rise in pulse pressure was associated with a significant 12% increase in the odds of having an elevated C-reactive protein level. Systolic and diastolic blood pressure were unrelated to C-reactive protein once pulse pressure had been accounted for. Our results suggest that increases in pulse pressure are associated with elevated C-reactive protein levels among apparently healthy US adults, independent of systolic and diastolic blood pressure.

Inhibition of platelet-collagen interaction: an in vivo action of insulin abolished by insulin resistance in obesity

Insulin resistance is associated with an increased risk of atherothrombotic vascular disease, but the mechanisms are poorly understood. We determined how insulin in vivo regulates platelet activation in nonobese and obese subjects by using methods mimicking thrombus formation. Twelve nonobese (aged 42+/-2 years, body mass index 24.0+/-0.4 kg/m(2)) and 14 obese (aged 43+/-1 years, body mass index 37.2+/-1.5 kg/m(2)) subjects were studied under euglycemic hyperinsulinemic (3-hour insulin infusion of 1 mU. kg(-1). min(-1)) conditions. Before and at the end of hyperinsulinemia, the following were determined: (1) platelet-related early hemostasis (shear rate of approximately 4000 s(-1)) by platelet function analysis; (2) platelet deposition to collagen during whole-blood perfusion (shear rate of 1600 s(-1)); (3) aggregation responses to collagen, thrombin receptor-activating peptide, ADP, and epinephrine; and (4) platelet cGMP concentrations. Insulin action on glucose metabolism was 69% lower in the obese subjects (1.6+/-0.2 mg. kg(-1). min(-1)) than in the nonobese subjects (5.4+/-0.4 mg. kg(-1). min(-1), P<0.0001). The in vivo insulin infusion inhibited platelet deposition to collagen from 4.3+/-0.6x10(6) to 3.5+/-0.4x10(6) per square centimeter in the nonobese subjects (P<0.05) but failed to do so in the obese subjects (5.2+/-0.8x10(6) versus 5.5+/-0.7x10(6) per square centimeter, P=NS; P<0.01 versus nonobese subjects). Epinephrine- and ADP-primed closure times by platelet function analysis were prolonged by insulin in the nonobese but not the obese subjects (P<0.05 for between-group difference). In the nonobese subjects, insulin decreased aggregation to all agonists and significantly increased platelet cGMP concentrations (2.5+/-0.3 versus 3.2+/-0.5 pmol/10(9) for before versus after insulin, respectively; P<0.01). In the obese subjects, insulin did not alter collagen-induced aggregation or cGMP concentrations (1.9+/-0.2 versus 1.8+/-0.1 pmol/10(9) for before versus the end of in vivo hyperinsulinemia, respectively; P=NS). These data demonstrate that normal in vivo insulin action inhibits platelet interaction with collagen under conditions mimicking thrombus formation and reduces aggregation to several agonists. These platelet-inhibitory actions of insulin are blunted or absent in obese subjects and could provide 1 mechanism linking insulin resistance to atherothrombotic disease.