Fosinopril decreases levels of soluble vascular cell adhesion molecule-1 in borderline hypertensive type II diabetic patients with microalbuminuria

Intracranial VCAM1 at time of mechanical thrombectomy predicts ischemic stroke severity

Background

Emergent large vessel occlusion (ELVO) strokes are devastating ischemic vascular events for which novel treatment options are needed. Using vascular cell adhesion molecule 1 (VCAM1) as a prototype, the objective of this study was to identify proteomic biomarkers and network signaling functions that are potential therapeutic targets for adjuvant treatment for mechanical thrombectomy.

Methods

The blood and clot thrombectomy and collaboration (BACTRAC) study is a continually enrolling tissue bank and registry from stroke patients undergoing mechanical thrombectomy. Plasma proteins from intracranial (distal to clot) and systemic arterial blood (carotid) were analyzed by Olink Proteomics for N=42 subjects. Statistical analysis of plasma proteomics used independent sample t tests, correlations, linear regression, and robust regression models to determine network signaling and predictors of clinical outcomes. Data and network analyses were performed using IBM SPSS Statistics, SAS v 9.4, and STRING V11.

Results

Increased systemic (p<0.001) and intracranial (p=0.013) levels of VCAM1 were associated with the presence of hypertension. Intracranial VCAM1 was positively correlated to both infarct volume (p=0.032; r=0.34) and edema volume (p=0.026; r=0.35). The %∆ in NIHSS from admittance to discharge was found to be significantly correlated to both systemic (p=0.013; r = −0.409) and intracranial (p=0.011; r = −0.421) VCAM1 levels indicating elevated levels of systemic and intracranial VCAM1 are associated with reduced improvement of stroke severity based on NIHSS from admittance to discharge. STRING-generated analyses identified biologic functional descriptions as well as function-associated proteins from the predictive models of infarct and edema volume.

Conclusions

The current study provides novel data on systemic and intracranial VCAM1 in relation to stroke comorbidities, stroke severity, functional outcomes, and the role VCAM1 plays in complex protein-protein signaling pathways. These data will allow future studies to develop predictive biomarkers and proteomic targets for drug development to improve our ability to treat a devastating pathology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02157-4.

Potential Protective Role of Blood Pressure-Lowering Drugs on the Balance between Hemostasis and Fibrinolysis in Hypertensive Patients at Rest and During Exercise

In patients with hypertension, the triad represented by endothelial dysfunction, platelet hyperactivity, and altered fibrinolytic function disturbs the equilibrium between hemostasis and fibrinolysis and translates into a hypercoagulable state, which underlies the risk of thrombotic complications. This article reviews the scientific evidence regarding some biological effects of antihypertensive drugs, which can protect patients from the adverse consequences of hypertensive disease, improving endothelial function, enhancing antioxidant activity, and restoring equilibrium between hemostatic and fibrinolytic factors. These protective effects appear not to be mediated through blood pressure reduction and are not shared by all molecules of the same pharmacological class.

Prognostic role of plasma von Willebrand factor and soluble E-selectin levels for future cardiovascular events in a 'real-world' community cohort of patients with atrial fibrillation

BACKGROUND

Endothelial damage/dysfunction may contribute to a prothrombotic state in patients with atrial fibrillation (AF) and the increased risk of thromboembolism and cardiovascular events. Raised plasma von Willebrand factor (vWf), an established marker of endothelial damage/dysfunction, has been associated with stroke and vascular events, at least in a clinical trial population. Soluble E-selectin (sE-sel) is another biomarker of endothelial activation/dysfunction, with more limited data on prognostic outcomes in AF.

OBJECTIVE

To assess the relationship between the levels of vWf, sE-sel and clinical adverse outcomes (including stroke, MI and all-cause mortality) in a 'real-world' community cohort of patients with AF.

METHODS

We studied 423 patients (mean age 72·7 ± 8·4 years, 55·6% male) with nonvalvular AF, with a median follow-up of 19 (9-31) months. Plasma vWf and sE-sel levels were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

There were 94 clinical adverse events (22·2%) observed during a median follow-up of 19 months. Patients with clinical events had significantly higher vWf (P < 0·001) and sE-sel levels at baseline (P < 0·001) compared with those who were event free. Kaplan-Meir analyses demonstrated that more clinical adverse events occurred in the upper tertile of vWf [upper vs. lowest tertile, RR 3·8, 95% CI (2·63-5·57), P < 0·001; upper vs. middle tertile, RR 10·5, 95% CI (5·33-20·60), P < 0·001]. Similarly, the highest tertile of sE-sel was associated with more adverse events [upper vs. lowest tertile, RR 3·7, 95% CI (2·51-5·31), P < 0·001; upper vs. middle tertile, RR 6·5, 95% CI (3·56-11·91), P < 0·001].

CONCLUSION

High plasma vWf and soluble E-selectin levels are associated with an increased risk of clinical adverse events (acute myocardial infarction, ischaemic stroke and all-cause mortality) in 'real-world' patients with AF. These soluble biomarkers may potentially aid clinical risk stratification in this common arrhythmia.

Increased inflammatory biomarkers in hypertensive type 2 diabetic patients: improvement after angiotensin II type 1 receptor blockade

Diabetes and hypertension increasingly are recognized as pro-inflammatory conditions. We tested the hypothesis that in patients with hypertension and type 2 diabetes, blood pressure (BP) reduction with an angiotensin receptor blocker (ARB), valsartan, or with a beta blocker, atenolol, is associated with a decreased inflammatory response. Normotensive subjects and hypertensive patients with type 2 diabetes (40 to 70 years of age) participated in the study. Patients (n = 28) were randomized to double-blind treatment for 1 year with valsartan (80-160 mg) or atenolol (50-100 mg) daily, added to previous therapy. Age-matched controls (n = 12) were also studied. Serum levels of cytokines (IL-6, IL-18), chemokines (MCP-1), and adhesion molecules (sICAM, sE-selectin) were measured by enzyme-linked immunosorbent assay (ELISA) as indices of systemic and vascular inflammation, before and 1 year after treatment. BP was similarly reduced by valsartan and atenolol. Glycemic control and lipid profiles were comparable in the two groups and did not change significantly with antihypertensive therapy. Serum levels of all inflammatory markers were increased in patients before treatment (by two- to four-fold vs. controls, P < .05). IL-6, IL-18, sICAM, and MCP-1 levels were reduced by valsartan (three-fold, P < .05). Only IL-18 was reduced by atenolol compared with pretreatment levels (P < .05). These data indicate that proinflammatory mediators are significantly increased in hypertensive type 2 diabetic patients and that despite similar BP lowering by valsartan and atenolol and similar glucose levels in both treated groups, global inflammatory status was improved only in the valsartan group. Our findings suggest that antihypertensive treatment, particularly with an ARB, ameliorates inflammatory processes in diabetic hypertensive patients. Such effects, which are independent of BP and glycemic control, may contribute to cardiovascular protection.

Current concepts in combination therapy for the treatment of hypertension: combined calcium channel blockers and RAAS inhibitors

Recent guidelines for the management of hypertension recommend target blood pressures <140/90 mmHg in hypertensive patients, or <130/80 mmHg in subjects with diabetes, chronic kidney disease, or coronary artery disease. Despite the availability and efficacy of antihypertensive drugs, most hypertensive patients do not reach the recommended treatment targets with monotherapy, making combination therapy necessary to achieve the therapeutic goal. Combination therapy with 2 or more agents is the most effective method for achieving strict blood pressure goals. Fixed-dose combination simplifies treatment, reduces costs, and improves adherence. There are many drug choices for combination therapy, but few data are available about the efficacy and safety of some specific combinations. Combination therapy of calcium antagonists and inhibitors of the renin-angiotensin-aldosterone system (RAAS) are efficacious and safe, and have been considered rational by both the JNC 7 and the 2007 European Society of Hypertension – European Society of Cardiology guidelines for the management of arterial hypertension. The aim of this review is to discuss some relevant issues about the use of combinations with calcium channel blockers and RAAS inhibitors in the treatment of hypertension.

Effects of nifedipine GITS 20 mg or enalapril 20 mg on blood pressure and inflammatory markers in patients with mild–moderate hypertension

OBJECTIVE

Calcium antagonists, angiotensin-converting enzyme (ACE) inhibitors and other drug classes either alone or in combination have been recommended for the treatment of hypertension. Nifedipine gastrointestinal therapeutic system (GITS) 20 mg is a new low-dose formulation with an improved tolerability. The aim of the present study was to compare the effects of nifedipine GITS 20 mg and enalapril 20 mg on blood pressure and circulating adhesion molecules in hypertensive patients.

METHODS

This randomized, double-blind, multicentre trial compared the blood pressure lowering effects of a 12-week treatment of nifedipine GITS 20 mg vs enalapril 20 mg in 264 patients with mild-to-moderate hypertension.

RESULTS

Nifedipine GITS 20 mg induced a reduction of clinic blood pressure, which was similar to that observed with enalapril 20 mg. Nifedipine GITS and enalapril lowered mean sitting diastolic blood pressure by 11.8 and 12.4 mmHg, respectively, while systolic blood pressure was reduced by 15.3 and 16.3 mmHg, respectively. Ambulatory blood pressure monitoring-derived blood pressure data showed similar results in both groups without any statistically significant differences between treatments. Both enalapril and nifedipine tended to reduce ICAM-1 and E-selectin, while only nifedipine reduced von Willebrand factor. Both treatments were well tolerated.

CONCLUSIONS

Our findings demonstrate a similar antihypertensive effectiveness of a low dose (20 mg) of nifedipine GITS in comparison with a standard dose of enalapril (20 mg). Given its clinical efficacy and good tolerability, low-dose nifedipine GITS may be considered a valuable treatment option for hypertensive patients.

The effect of trandolapril and its fixed-dose combination with verapamil on circulating adhesion molecules levels in hypertensive patients with type 2 diabetes

BACKGROUND AND AIM

Endothelial dysfunction in hypertensive type-2 diabetic patients is associated with increased levels of circulating soluble adhesion molecules (SAM). SAM participate in the development of diabetic macroangiopathy and microangiopathy. The aim of this study was to compare the effect of trandolapril (T) and its fixed-dose combination with verapamil (FDTV) on SAM levels in hypertensive type-2 diabetic patients.

METHODS

Forty type-2 diabetic patients with never-treated hypertension were randomly assigned to two groups. One group (FDTV) received 2/180 mg once a day; the other group received T 2 mg once a day. Study drugs were administered for three months in both groups. VCAM-1, ICAM, and E-selectin were measured by ELISA at the beginning and end of the study. Patients were evaluated monthly for blood pressure, fasting serum glucose, and adverse events. Statistical analysis was performed with ANOVA.

RESULTS

Both therapeutics regimens reduced significantly the levels of the SAM tested. When both groups were compared, we did not find a significant difference in ICAM and E-selectin reduction. However, VCAM-1 presented a significantly greater reduction (p = 0.022) in the trandolapril-verapamil group. No patient suffered adverse events.

CONCLUSION

Our results show that FDTV produces a greater reduction of VCAM-1 circulating levels than trandolapril alone. This may explain some of the beneficial effects of this fixed dosed combination that are non-related to its antihypertensive effects.

Renoprotective effect of rosiglitazone through the suppression of renal intercellular adhesion molecule-1 expression in streptozotocin-induced diabetic rats

OBJECTIVE

To observe the effect of rosiglitazone on serum intercellular adhesion molecule-1 (SICAM-1) level, urinary excretion of ICAM-1, and renal expression of ICAM-1, and investigate its possible renoprotective mechanisms in diabetic rats.

METHOD

Twenty-four Wistar Rats were divided into 3 groups: non-diabetic control rats (group A, no.=8), streptozotocin-induced diabetic rats (group B, no.=8), and diabetic rats treated with rosiglitazone (group C, no.=8). Rats in group C were treated with rosiglitazone (5 mg x kg(-1) x d(-1)) 1 week after the establishment of diabetic model, group A and B were treated with corresponding sodium chloride. Peripheral blood glucose was tested weekly. Glycosylated hemoglobin (HbA1c) and SICAM-1 as well as urinary albumin excretion rate (UAER), urinary retinol binding-protein (URBP) excretion rate, and urinary ICAM-1 (UICAM- 1) excretion rate were tested at the 8th week, and the renal tissues of all rats were obtained for evaluating kidney/body weight ratio, observing pathologic change via electron microscope, and for examining the expression of ICAM-1 mRNA by reverse transcriptase-PCR.

RESULTS

At the 8th week, the blood glucose, HbA1c levels, UAER, URBP excretion rate, kidney/body weight ratio and serum, urinary ICAM-1 levels all increased significantly in group B and group C in comparison with group A; however, the above-mentioned parameters in group C (except the blood glucose and HbA1c levels) were much lower than those in group B. In addition, both SICAM-1 and UICAM-1 were highly correlated with the UAER, URBP level, and kidney/body weight ratio in all rats; renal pathological lesions observed by electron microscope in group C were much lighter than those of group B; compared with group A, the expression of ICAM-1 mRNA was markedly up-regulated in group B and group C, and rosiglitazone was able to decrease the expression of ICAM-1 mRNA in the renal tissue.

CONCLUSION

Rosiglitazone could definitely protect against the renal injury of diabetic rats, which may be partly associated with decreasing the expression of ICAM-1 in the renal tissue, reducing ICAM-1 productions in both serum and urine.

Endothelial dysfunction in diabetes mellitus

Diabetes mellitus is associated with an increased risk of cardiovascular disease, even in the presence of intensive glycemic control. Substantial clinical and experimental evidence suggest that both diabetes and insulin resistance cause a combination of endothelial dysfunctions, which may diminish the anti-atherogenic role of the vascular endothelium. Both insulin resistance and endothelial dysfunction appear to precede the development of overt hyperglycemia in patients with type 2 diabetes. Therefore, in patients with diabetes or insulin resistance, endothelial dysfunction may be a critical early target for preventing atherosclerosis and cardiovascular disease. Microalbuminuria is now considered to be an atherosclerotic risk factor and predicts future cardiovascular disease risk in diabetic patients, in elderly patients, as well as in the general population. It has been implicated as an independent risk factor for cardiovascular disease and premature cardiovascular mortality for patients with type 1 and type 2 diabetes mellitus, as well as for patients with essential hypertension. A complete biochemical understanding of the mechanisms by which hyperglycemia causes vascular functional and structural changes associated with the diabetic milieu still eludes us. In recent years, the numerous biochemical and metabolic pathways postulated to have a causal role in the pathogenesis of diabetic vascular disease have been distilled into several unifying hypotheses. The role of chronic hyperglycemia in the development of diabetic microvascular complications and in neuropathy has been clearly established. However, the biochemical or cellular links between elevated blood glucose levels, and the vascular lesions remain incompletely understood. A number of trials have demonstrated that statins therapy as well as angiotensin converting enzyme inhibitors is associated with improvements in endothelial function in diabetes. Although antioxidants provide short-term improvement of endothelial function in humans, all studies of the effectiveness of preventive antioxidant therapy have been disappointing. Control of hyperglycemia thus remains the best way to improve endothelial function and to prevent atherosclerosis and other cardiovascular complications of diabetes. In the present review we provide the up to date details on this subject.

Cardiovascular disease in diabetic nephropathy patients: cell adhesion molecules as potential markers?

Cardiovascular disease is a major complication of diabetes mellitus, especially for patients with diabetic nephropathy. The underlying factor or pathogenic mechanism that links diabetic nephropathy with cardiovascular disease is not known. The endothelial cell adhesion molecules, intercellular adhesion molecule-1 or vascular cell adhesion molecule-1, play a crucial role in the initiation of atherosclerosis. Levels of both cell adhesion molecules are raised by the diabetic and kidney disease states. This review focuses on these important cell adhesion molecules and their role in the pathogenesis of cardiovascular disease in diabetes and diabetic nephropathy.

Irbesartan treatment reduces biomarkers of inflammatory activity in patients with type 2 diabetes and microalbuminuria: an IRMA 2 substudy

The impact of irbesartan treatment on biomarkers of low-grade inflammation, endothelial dysfunction, growth factors, and advanced glycation end products (AGEs) during the Irbesartan in Patients with Type 2 Diabetes and Microalbuminuria (IRMA 2) study was evaluated. IRMA 2 was a 2-year multicenter, randomized, double-blind trial in patients comparing irbesartan (150 or 300 mg once daily) versus placebo. The primary end point was onset of overt nephropathy. A subgroup (n = 269, 68%) was analyzed for biomarkers at baseline and after 1 and 2 years. High-sensitivity C-reactive protein (hs-CRP), interleukin (IL)-6, fibrinogen, adhesion molecules, transforming growth factor-beta, and AGE peptides were assessed. Irbesartan treatment yielded significant changes in hs-CRP (based on generalized estimating equation regression coefficient) with a 5.4% decrease per year versus a 10% increase per year in the placebo group (P < 0.001). Fibrinogen decreased 0.059 g/l per year from baseline versus placebo's 0.059 g/l increase per year (P = 0.027). IL-6 showed a 1.8% increase per year compared with placebo's 6.5% increase per year (P = 0.005). Changes in IL-6 were associated with changes in albumin excretion (P = 0.04). There was no treatment effect on the other biomarkers. Irbesartan (300 mg once daily) reduces low-grade inflammation in this high-risk population, and this may reduce the risk of micro- and macrovascular disease.

Microalbuminuria and endothelial dysfunction: emerging targets for primary prevention of end-organ damage

A minor increase in urinary albumin excretion (microalbuminuria) is known to predict adverse renal and cardiovascular events in diabetic and hypertensive patients. Recent intriguing findings show that microalbuminuria is an early and sensitive marker of future cardiovascular events even in healthy subjects. The mechanisms linking microalbuminuria with end-organ damage have not been fully explained yet; however, generalized endothelial dysfunction might play an important role. Prevailing experimental and clinical data suggest that generalized endothelial dysfunction, frequently characterized by decreased nitric oxide bioavailability, actually precedes the development of microalbuminuria. This review summarizes the current knowledge about the intricate relationship between microalbuminuria and endothelial dysfunction. On the basis of the current evidence, we propose that microalbuminuria and endothelial dysfunction are an emerging target for primary prevention strategies in cardiovascular disease. In near future, dietary components improving nitric oxide bioavailability, such as cocoa-derived flavanols may play important role in these preventive strategies.

Elevation of serum soluble E- and P-selectin in patients with hypertension is reversed by benidipine, a long-acting calcium channel blocker

Hypertension is a major risk factor for atherosclerotic cardiovascular disease. Selectins, cell-surface adhesion molecules involved in leukocyte rolling and attachment to the vascular endothelium, play a role in the initiation of atherosclerosis. We investigated whether or not serum levels of soluble adhesion molecules are elevated in patients with essential hypertension (EH) and examined whether antihypertensive therapy lowers such levels. Twenty-one patients who had untreated mild to moderate EH without diabetes mellitus, hyperlipidemia, or obesity were recruited at a clinic for hypertensive patients. Blood pressure was measured, and the serum levels of soluble E-selectin, P-selectin, L-selectin, intercellular adhesion molecule 1 (ICAM-1), and vascular-cell adhesion molecule 1 (VCAM-1) were determined by enzyme-linked immunosorbent assays before and after 12, 24, and 53 weeks of antihypertensive treatment with benidipine, a long-acting calcium channel blocker, given at a dose of 6 mg/day for 53 weeks. As a control, 21 age- and sex-matched patients without hypertension were studied. Serum E- and P-selectin levels were significantly higher in the subjects with EH than in the controls (p < 0.01). There were no differences in serum levels of soluble L-selectin, VCAM-1, or ICAM-1 levels between the patients with EH and the controls. Treatment with benidipine decreased the elevated blood pressure over a 53-week study period (mean blood pressure: 119.8 +/- 6.5 mmHg at baseline, 101.0 +/- 5.9 mmHg at 12 weeks, 98.6 +/- 7.3 mmHg at 24 weeks, and 93.9 +/- 5.5 mmHg at 53 weeks). Serum levels of soluble E- and P-selectin decreased after the initiation of benidipine treatment and correlated with diastolic blood pressure. Serum levels of soluble L-selectin, VCAM-1, and ICAM-1 did not change significantly during the period of benidipine treatment. Benidipine treatment reduced the content of P-selectin in the platelets from patients with EH, as determined by Western blot analysis. In conclusion, decreased blood pressure may reduce the rate of progression of atherosclerosis by affecting the expression of E- and P-selectin in the endothelium, the platelets, or both. Benidipine may be protective against vascular damage in people with hypertension, not only by lowering blood pressure, but also by inhibiting the expression of selectins.

Renal and vascular hypertension-induced inflammation: role of angiotensin II

PURPOSE OF REVIEW

We will focus on the recent findings concerning the inflammatory response in vascular and renal tissues caused by hypertension.

RECENT FINDINGS

Angiotensin II is one of the main factors involved in hypertension-induced tissue damage. This peptide regulates the inflammatory process. Angiotensin II activates circulating cells, and participates in their adhesion to the activated endothelium and subsequent transmigration through the synthesis of adhesion molecules, chemokines and cytokines. Among the intracellular signals involved in angiotensin II-induced inflammation, the production of reactive oxygen species and the activation of nuclear factor-kappaB are the best known.

SUMMARY

The pharmacological blockade of angiotensin II actions, by angiotensin-converting enzyme inhibitors or angiotensin receptor antagonists, results in beneficial organ protective effects, in addition to the effects of these agents on blood pressure control, that can be explained by the blockade of the angiotensin II-induced pro-inflammatory response. These data provide a rationale for the use of blockers of the renin-angiotensin system to prevent vascular and renal inflammation in patients with hypertension.

Endothelial dysfunction: Mechanisms of development and therapeutic options

Introduction. Vascular endothelial cells play a key role in cardiovascular regulation by producing a number of potent vasoactive agents, including the vasodilator molecule nitric oxide (NO) and the vasoconstrictor peptide endothelin (ET). Endothelial dysfunction. Endothelial dysfunction is recognized as the initial step in the atherosclerotic process. Impairment of NO synthesis, or increased inactivation of NO by superoxide radicals, may account for the increased peripheral vascular tone, as well as contribute to the clinical consequences of different pathophysiological conditions-which include vascular hypertrophy, increased platelet and monocyte adhesion to the endothelium, atherosclerosis, myocardial infarction and stroke. To date, most interventions attempting to improve endothelial dysfunction have targeted one or more of the numerous risk factors that can cause endothelial damage: hypertension (ACE inhibitors and calcium antagonists), hypercholesterolemia (lipid-lowering agents), cigarette smoking (cessation), sedentary lifestyle (increased physical activity), menopause (estrogen replacement therapy), and diabetes mellitus (control of metabolic abnormalities). Several pharmacologic agents have been suggested to achieve vascular protection through mechanisms that go beyond their primary therapeutic actions (ACE-and HMG-CoA reductase inhibitors). Beneficial changes to the endothelium might result from promotion of vasorelaxation, inhibition of vasoconstriction, reduction in the production of free radicals, or other mechanisms that protect the endothelium from injury. Conclusion. This study deals with the results of many experimental and clinical investigations. The possibility of using different classes of drugs was also established, including ACE inhibitors, Ca-antagonists, AT and endothelin receptor antagonists, direct activator of adenyl cyclase, statins, antioxidants, L-arginine, phosphodiesterase inhibitors, beta-blockers and organic nitrates. .

Diabetes mellitus-associated atherosclerosis: mechanisms involved and potential for pharmacological invention

While diabetes mellitus is most often associated with hypertension, dyslipidemia, and obesity, these factors do not fully account for the increased burden of cardiovascular disease in patients with the disease. This strengthens the need for comprehensive studies investigating the underlying mechanisms mediating diabetic cardiovascular disease and, more specifically, diabetes-associated atherosclerosis. In addition to the recognized metabolic abnormalities associated with diabetes mellitus, upregulation of putative pathological pathways such as advanced glycation end products, the renin-angiotensin system, oxidative stress, and increased expression of growth factors and cytokines have been shown to play a causal role in atherosclerotic plaque formation and may explain the increased risk of macrovascular complications. This review discusses the methods used to assess the development of atherosclerosis in the clinic as well as addressing novel biomarkers of atherosclerosis, such as low-density lipoprotein receptor-1. Experimental models of diabetes-associated atherosclerosis are discussed, such as the streptozocin-induced diabetic apolipoprotein E knockout mouse. Results of major clinical trials with inhibitors of putative atherosclerotic pathways are presented. Other topics covered include the role of HMG-CoA reductase inhibitors and fibric acid derivatives with respect to their lipid-altering ability, as well as their emerging pleiotropic anti-atherogenic actions; the effect of inhibiting the renin-angiotensin system by either ACE inhibition or angiotensin II receptor antagonism; the effect of glycemic control and, in particular, the promising role of thiazolidinediones with respect to their direct anti-atherogenic actions; and newly emerging mediators of diabetes-associated atherosclerosis, such as advanced glycation end products, vascular endothelial growth factor and platelet-derived growth factor. Overall, this review aims to highlight the observation that various pathways, both independently and in concert, appear to contribute toward the pathology of diabetes-associated atherosclerosis. Furthermore, it reflects the need for combination therapy to combat this disease.

Aggressive antihypertensive therapy based on hydrochlorothiazide, candesartan or lisinopril as initial choice in hypertensive type II diabetic individuals: effects on albumin excretion, endothelial function and inflammation in a double-blind, randomized clinical trial

We investigated the effects of aggressive antihypertensive therapy based on hydrochlorothiazide, candesartan or lisinopril on urinary albumin excretion, endothelial function and inflammatory activity in hypertensive type II diabetic individuals. A total of 70 hypertensive type II diabetic individuals were treated with three antihypertensive strategies in a randomized, double-blind, double-dummy design. Blood pressure was titrated to levels below 130/85 mmHg or a decrease in systolic pressure of 10% with a diastolic pressure below 85 mmHg. After titration, patients were treated for 12 months. Mean blood pressures changed from 157/93, 151/94 and 149/93 at baseline to 135/80, 135/82 and 131/80 mmHg after titration in the hydrochlorothiazide (n=24), candesartan (n=24) and lisinopril (n=22) groups. About 70% reached target blood pressures. However, only 45% had blood pressures <130/85 mmHg. Urinary albumin excretion and levels of soluble vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 decreased (GEE regression coefficients, -2.40 mg/24 h (P<0.001), -85 ng/ml (P=0.01) and -50 ng/ml (P=0.02)), but brachial artery endothelium-dependent and -independent vasodilation and levels of von Willebrand factor and C-reactive protein did not change (GEE regression coefficients, 0.21 mm (P=0.07), 0.04 mm (P=0.43), 0.04 IU/ml (P=0.33) and -1.15 mg/l (P=0.64)). No differences in outcome variables between treatment groups were observed. These data show that achievement of target blood pressures below 130/85 mmHg in hypertensive type II diabetes is difficult. Aggressive antihypertensive therapy can improve urinary albumin excretion, endothelial function and inflammatory activity in hypertensive type II diabetic individuals, regardless of the type of antihypertensive therapy used.

Effects of candesartan cilexetil and enalapril on inflammatory markers of atherosclerosis in hypertensive patients with non-insulin-dependent diabetes mellitus

OBJECTIVE

Circulating adhesion molecules may have a prognostic significance as markers of endothelial damage. Drugs which inhibit the renin-angiotensin system may be effective in reducing circulating or tissue adhesion molecules, albeit data available are scarce. The aim of the study was to investigate the effects of an angiotensin-converting enzyme (ACE) inhibitor, enalapril and a highly selective angiotensin receptor blocker, candesartan cilexetil, on circulating adhesion molecules in a large sample of patients with non-insulin-dependent diabetes mellitus (NIDDM). The study was comparative, multicenter, randomized and double blind, with two parallel groups.

PATIENTS AND METHODS

NIDDM patients with a diagnosis of mild (grade 1) essential hypertension were included in the study, at the end of a 2-week placebo run-in period. The primary end-point of the study was to evaluate changes of intercellular adhesion molecule-1 (ICAM-1) plasma levels during treatment. The secondary end-points were: changes in vascular cells adhesion molecule-1 (VCAM-1), von Willebrand factor (vWF), fibrinogen and plasminogen activator inhibitor-1 (PAI-1) circulating levels and of urinary albumin excretion rate (AER) as well; 129 patients were randomized: 66 in the candesartan group and 63 in the enalapril group, 118 of them completed the scheduled 24-week treatment period.

RESULTS

Candesartan and enalapril equally reduced circulating level of ICAM-1 and exerted comparable effects on changes of other adhesion molecules and coagulation factors. A similar blood pressure-lowering effect was observed with the two drugs (candesartan: from 148/90 +/- 11/8 to 132/82 +/- 12/7 mmHg, P < 0.01, enalapril: from 148/91 +/- 12/8 to 131/85 +/- 14/6 mmHg, P < 0.01). Candesartan was more effective than enalapril in the reduction of albuminuria (P < 0.05 between treatments), although urinary protein excretion can be considered normal in the majority of patients. The two drugs were comparable in terms of adverse events reported.

CONCLUSION

Candesartan and enalapril showed similar effects on blood pressure and on circulating adhesion molecules. In this study urinary protein excretion was reduced more by candesartan.

Angiotensin receptor blockade decreases markers of vascular inflammation

A protective role against atherosclerosis can be attributed to angiotensin converting enzyme inhibitors (ACE-I), since they have been shown to reduce mortality in patients at cardiovascular risk. Since plasma levels of adhesion molecules are considered surrogate markers of endothelial cell activation and atherogenesis, we compared the levels of adhesion molecules after treatment with the ACE-I enalapril or the direct angiotensin- receptor antagonist losartan or placebo. In a randomized, controlled trial, 21 hypercholesterolemic volunteers received 50 mg/d losartan or 20 mg/d enalapril or placebo for twelve weeks. Plasma levels of circulating intercellular adhesion molecule-1 (cICAM-1), vascular adhesion molecule-1 (cVCAM-1), and E-selectin (cE-SEL) were measured by ELISA. Surface expression of ICAM-1 on circulating leukocytes was determined by flow cytometry. Enalapril and losartan but not placebo induced a small but stable decrease of cICAM-1 and cVCAM-1, while cE-SEL and leukocyte expression of ICAM-1 remained unchanged. The lowering of plasma adhesion molecules may indicate an antiatherogenic effect of angiotensin II blockade in hypercholesterolemia. While such preventive effect will have to be proven in clinical trials, our results do not support a preference for either enalapril or losartan with regard to their possible vasoprotective role.

Effects of AT1 receptor antagonist losartan on sICAM-1 and TNF-alpha levels in uncomplicated hypertensive patients

This study was designed to determine whether the levels of soluble intercellular adhesion molecule-1 (sICAM-1) and tumor necrosis factor-alpha (TNF-alpha) were elevated in subjects with uncomplicated hypertension who presented with no other risk factors or evidence of athero-sclerosis. The effects of administration of an angiotensin type-1 antagonist (losartan) on the serum concentrations of these molecules were also examined. Twenty hypertensive (HT) subjects (12 men and 8 women, mean age 49.1 +/-7.2 years) without other risk factors or cardiovascular disease received placebo for 4 weeks. The patients were then treated with losartan (50 mg/day) for 24 weeks. After 4, 12, and 24 weeks of losartan treatment, sICAM-1 and TNF-alpha levels were measured. The same parameters were measured in 20 normotensive control subjects (C), matched for sex and age. HT had sICAM-1 and TNF-alpha basal values higher than C (respectively 351.7 +/-97.4 vs 201.6 +/-32.3 ng/mL, p<0.001 and 31.8 +/-2.4 vs 15.3 +/-2.2 pg/mL, p<0.001). There was a positive correlation between sICAM-1 and TNF-alpha levels, but no correlation in HT between the average diastolic and systolic blood pressure (clinic and ambulatory monitoring) and the sICAM-1 or TNF-alpha levels was observed. Losartan treatment caused a significant decrease of sICAM-1 levels at the end of the first month of treatment (300.2 +/-64.4 ng/mL, p<0.05), but the values reverted to the basal levels at the following time points. No variation of TNF-alpha levels during losartan treatment was observed. These results show that patients with uncomplicated mild essential hypertension presented with high plasma ICAM-1 and TNF-alpha concentrations. Although all the patients were responsive to the antihypertensive treatment with losartan, their plasma concentrations of TNF-alpha were not modified, and sICAM-1 concentrations decreased only for a short period of time. This suggests that in uncomplicated hypertension other factors besides the blood pressure modulate the endothelial inflammation.

Differential effects of fenofibrate versus atorvastatin on the concentrations of E-selectin and vascular cellular adhesion molecule-1 in patients with type 2 diabetes mellitus and mixed hyperlipoproteinemia: a randomized cross-over trial

Background

Diabetic dyslipoproteinemia is characterized by hypertriglyceridemia, low HDL-cholesterol and often elevated LDL-cholesterol and is a strong risk factor for atherosclerosis. Adhesion molecule levels are elevated both in hyperlipoproteinemia and diabetes mellitus. It is unclear whether fibrate or statin therapy has more beneficial effects on adhesion molecule concentrations.

Methods

Atorvastatin (10 mg/d) was compared to fenofibrate (200 mg/d) each for 6 weeks separated by a 6 week washout period in 11 patients (6 male, 5 female; 61.8 ± 8.2 years; body mass index 29.8 ± 3.1 kg/m²) with type 2 diabetes mellitus (HbA_1c 7.3 ± 1.1 %) and mixed hyperlipoproteinemia using a randomized, cross-over design. Fasting blood glucose, HbA₁c, lipid parameters, E-selectin, ICAM-1, VCAM-1, and fibrinogen concentrations were determined before and after each drug.

Results

Glucose and HbA₁c concentrations remained unchanged during the whole study period. LDL cholesterol was reduced during atorvastatin therapy, triglycerides were lowered more effectively with fenofibrate. Comparison of pre- and postreatment concentrations of E-selectin showed a reduction during atorvastatin (-7 %, p = 0.11) and fenofibrate (-10 %, p < 0.05) therapy. Atorvastatin treatment reduced VCAM-1 levels by 4% (p < 0.05), while VCAM-1 concentrations remained unchanged (+1%, ns) during fenofibate therapy. However, direct comparisons of post-treatment levels during both forms of therapy were not of statistical significance. ICAM-1 levels were not influenced by either form of therapy.

Conclusions

In addition to the different beneficial effects on lipid metabolism, both drugs appear to lower adhesion molecule plasma concentrations in a different manner in patients with type 2 diabetes and mixed hyperlipoproteinemia. Our observations should be confirmed in a larger cohort of such patients.

Circulating adhesion molecules and carotid artery structural changes in patients with noninsulin-dependent diabetes mellitus

Hypertension and non insulin-dependent diabetes mellitus (NIDDM) are well-known risk factors for atherosclerotic disease. Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) may exert a relevant role in the pathogenesis of atherosclerosis; their prognostic relevance has been recently demonstrated. The aim of the study was to investigate possible inter-relation between circulating adhesion molecule levels, carotid artery structure and endothelial function in 15 patients with NIDDM, as well as in 15 patients with both NIDDM and essential hypertension (NIDDM+EH) compared with 15 normal subjects (NS) and 15 euglycaemic patients with EH, matched for age, sex and body weight. All subjects were submitted to a biopsy of the gluteal subcutaneous fat. Small arteries were dissected and mounted on a micromyograph, and the media-to-lumen (M/L) ratio was then calculated. Carotid artery structure was investigated by Doppler ultrasound. Endothelial function was evaluated by investigation of the flow-mediated dilatation (FMD) of the brachial artery. ICAM-1 and VCAM-1 plasma levels were measured by ELISA. ICAM-1 and VCAM-1 plasma levels were significantly greater and FMD smaller in EH, NIDDM and NIDDM+EH than in NS, but no difference was observed among the three pathological groups. Carotid artery structural changes were more pronounced in NIDDM+EH. No significant difference was observed among NIDDM, EH and NS. The M/L ratio of subcutaneous small resistance arteries was significantly greater in NIDDM+EH than in NIDDM or EH. NS had a smaller M/L ratio than the other groups. Significant correlations were observed between ICAM-1 plasma levels and indices of carotid artery structure in diabetic patients. However, the relations were close only in NIDDM+EH. In conclusion, our data suggest that NIDDM+EH may present more pronounced vascular structural alterations than NIDDM, and that adhesion molecules plasma levels are closely inter-related with carotid artery structural alterations, at least in NIDDM+EH, but not with M/L ratio of small resistance arteries.

Inflammation and angiotensin II

Angiotensin II (AngII), the major effector peptide of renin-angiotensin system (RAS), is now recognized as a growth factor that regulates cell growth and fibrosis, besides being a physiological mediator restoring circulatory integrity. In the last few years, a large number of experimental studies has further demonstrated that AngII is involved in key events of the inflammatory process. Here, we summarize the wide variety of AngII functions and discuss them in relation with the inflammatory cascade. AngII increases vascular permeability (via the release of prostaglandins and vascular endothelial cell growth factor or rearrangement of cytoskeletal proteins) that initiates the inflammatory process. AngII could contribute to the recruitment of inflammatory cells into the tissue through the regulation of adhesion molecules and chemokines by resident cells. Moreover, AngII could directly activate infiltrating immunocompetent cells, including chemotaxis, differentiation and proliferation. Recent data also suggest that RAS activation could play a certain role even in immunologically-induced inflammation. Transcriptional regulation, predominantly via nuclear factor-kappaB (NF-kappaB) and AP-1 activation, and second mediator systems, such as endothelin-1, the small G protein (Rho) and redox-pathways are shown to be involved in the molecular mechanism by which AngII exerts those functions. Finally, AngII participates in tissue repair and remodeling, through the regulation of cell growth and matrix synthesis. In summary, recent data support the hypothesis that RAS is key mediator of inflammation. Further understanding of the role of the RAS in this process may provide important opportunities for clinical research and treatment of inflammatory diseases.

Enalapril does not alter adhesion molecule levels in human endotoxemia

The angiotensin-converting enzyme inhibitor (ACE-I) enalapril has been shown to lower elevated levels of circulating adhesion molecules (cAM) in critically ill patients. To delineate the mechanisms of this possibly beneficial effect of enalapril, we studied the acute effects of enalapril in a well-defined model of endotoxin-triggered, cytokine-mediated cAM up-regulation. In a randomized, controlled trial, 30 healthy male volunteers received 2 ng/kg lipopolysaccharide (LPS) after pretreatment with placebo or 20 mg/day enalapril for 5 days or with a single dose of 20 mg of enalapril 2 h before LPS infusion. LPS infusion increased TNF levels 300-fold above normal, circulating (c) E-selectin levels by 425% (CI, 359%-492%), and P-selectin, VCAM-1, ICAM-1, and von Willebrand factor levels by 47%-74%. LPS infusion also enhanced ICAM-1 and CD11b expression 2- to 3-fold on monocytes. However, no differences were seen between treatment groups (P > 0.05), despite 95% inhibition of ACE activity by enalapril. Inhibition of ACE activity by enalapril does not influence plasma indices of endothelial activation after endotoxin infusion in healthy individuals. Our results do not support the concept of a beneficial clinical effect of enalaprilat in septicemia.

Myeloperoxidase and plasminogen activator inhibitor 1 play a central role in ventricular remodeling after myocardial infarction

Left ventricular (LV) remodeling after myocardial infarction (MI) results in LV dilation, a major cause of congestive heart failure and sudden cardiac death. Ischemic injury and the ensuing inflammatory response participate in LV remodeling, leading to myocardial rupture and LV dilation. Myeloperoxidase (MPO), which accumulates in the infarct zone, is released from neutrophils and monocytes leading to the formation of reactive chlorinating species capable of oxidizing proteins and altering biological function. We studied acute myocardial infarction (AMI) in a chronic coronary artery ligation model in MPO null mice (MPO(-/-)). MPO(-/-) demonstrated decreased leukocyte infiltration, significant reduction in LV dilation, and marked preservation of LV function. The mechanism appears to be due to decreased oxidative inactivation of plasminogen activator inhibitor 1 (PAI-1) in the MPO(-/-), leading to decreased tissue plasmin activity. MPO and PAI-1 are shown to have a critical role in the LV response immediately after MI, as demonstrated by markedly delayed myocardial rupture in the MPO(-/-) and accelerated rupture in the PAI-1(-/-). These data offer a mechanistic link between inflammation and LV remodeling by demonstrating a heretofore unrecognized role for MPO and PAI-1 in orchestrating the myocardial response to AMI.

Circulating intercellular cell adhesion molecule-1, endothelin-1 and von Willebrand factor-markers of endothelial dysfunction in uncomplicated essential hypertension: the effect of treatment with ACE inhibitors

The aim of the study was to examine whether the circulating cell adhesion molecules, von Willebrand factor (vWf) and endothelin-1, are elevated in patients with essential hypertension with no other risk factors for atherosclerosis and thus may serve as a markers of endothelial dysfunction in uncomplicated hypertension. Furthermore, the effect of treatment with the ACE inhibitor, quinapril, on levels of endothelial dysfunction markers were studied. The levels of adhesion molecules (intercellular cell adhesion molecule-1 [ICAM-1], E-selectin, P-selectin), von Willebrand factor (vWf) and endothelin-1 were measured in patients with hypertension without any other risk factors of atherosclerosis before and after treatment with quinapril (n = 22) and in normotensive controls (n = 22). Compared with normotensive subjects, the hypertensive patients had significantly higher levels of ICAM-1 (238 vs 208 ng/ml, P = 0.02), vWf (119 vs 105 IU/dl, P < 0.05) and endothelin-1 (5.76 vs 5.14 fmol/ml, P < 0.05). Three-month treatment of hypertensive patients with quinapril led to a significant decrease in the levels of endothelin-1 (5.76 vs 5.28 fmol/ml, P < 0.01). We did not observe significant changes in the levels of adhesion molecules and vWf after ACE inhibitor treatment, although a trend toward a decrease was apparent with all these parameters. Patients with uncomplicated hypertension with no other risk factors of atherosclerosis had significantly elevated levels of ICAM-1, vWf, and endothelin-1. Our data suggest that these factors may serve as markers of endothelial damage even in uncomplicated hypertension. In hypertensive patients, treatment with the ACE inhibitor quinapril resulted in a significant decrease in endothelin-1 levels. These findings indicate a beneficial effect of ACE inhibitors on endothelial dysfunction in hypertensive patients.

Role of ACE inhibitors in treating hypertensive diabetic patients

Cardiovascular disease (CVD) is a major determining factor of morbidity and mortality in type 2 diabetic patients. Hypertension, which accompanies diabetes in more than 70% of cases, contributes to increased prevalence of CVD events in this group of patients. Results from the United Kingdom Prospective Diabetes Study (UKPDS) indicated that reduction of elevated blood pressure might decrease CVD morbidity and mortality more than reduction of hyperglycemia. Activation of circulating and tissue renin-angiotensin system (RAS) contributes to the development of both hypertension and insulin resistance in patients with the cardiometabolic syndrome. Angiotensin-converting enzyme (ACE) inhibitor therapy in patients with the cardiometabolic syndrome may improve insulin action as well as lessen CVD. In clinical trials, ACE inhibitors have been shown to be more efficient than other antihypertensive medications (i.e., calcium channel blockers) in the reduction of CVD morbidity and mortality in hypertensive diabetics. In this article, we summarize possible mechanisms by which ACE inhibition may improve insulin resistance, coagulation/clotting, and vascular function abnormalities, and postpone or even prevent the development of type 2 diabetes in hypertensive patients.

Effects of severe, uncontrolled hypertension on endothelial activation: soluble vascular cell adhesion molecule-1, soluble intercellular adhesion molecule-1 and von Willebrand factor

OBJECTIVES

The molecular mechanisms whereby severe, uncontrolled hypertension (SHT) is translated into acute vascular target organ dysfunction have not been completely defined. We sought to determine whether SHT is associated with pressure-dependent endothelial activation as assessed by soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1) and von Willebrand Factor (vWF).

METHODS

We determined sVCAM-1, sICAM-1 and vWF in three groups: (i) untreated patients referred specifically for treatment of SHT [diastolic blood pressure (DBP) > or = 120 mm Hg; n = 24]; (ii) untreated patients with established mild hypertension (MHT; DBP 95-100 mmHg; n = 19); and (iii) normotensive volunteers (DBP < or = 90; n = 16).

RESULTS

By analysis of variance, sVCAM-1 (P = 0.002), sICAM-1 (P = 0.02) and vWF (P = 0.009) were greater in SHT and MHT than in normotensives but did not differ between SHT and MHT. We observed a significant positive correlation between blood pressure and soluble activation markers at lower blood pressures (normotensives and MHT considered together) that was not present in SHT.

CONCLUSIONS

Even mild elevation of blood pressure may be sufficient to activate the expression of adhesion molecules. Mechanisms other than the endothelial expression of adhesion molecules may be important in mediating the accelerated target organ injury produced by SHT in humans. Concentrations of soluble adhesion molecules and vWF may depend more strongly upon factors in the hypertensive microenvironment other than the absolute level of blood pressure.

Role of angiotensin II type 1 receptor in the regulation of cellular adhesion molecules in atherosclerosis

BACKGROUND

Inflammation is a central feature of coronary artery disease (CAD) that is characterized by increased expression of cellular adhesion molecules with the exception of L-selectin. L-selectin is a leukocyte adhesion molecule that is rapidly shed after leukocyte activation so that it appears to be decreased in CAD. The renin-angiotensin system (RAS) is implicated in atherogenesis and up-regulates these molecules.

OBJECTIVES

The aim of this study was to investigate the effect of angiotensin type 1 (AT1) receptor antagonism on serum and leukocyte adhesion molecule expression in patients with CAD. Blood samples were collected from 31 patients before and after 8 weeks of treatment with losartan (44 +/- 2 mg/d, mean +/- SE), an AT1 receptor antagonist. We measured serum intercellular adhesion molecule-1, vascular cell adhesion molecule-1, endothelial-leukocyte adhesion molecule, and C-reactive protein (CRP). By flow cytometry, we also measured the expression of leukocyte CD11a, CD11b, CD11c, CD18, CD31, CD49d, and CD62L (L-selectin) in 13 patients.

RESULTS

Treatment with losartan decreased systolic blood pressure (141 +/- 3 vs 135 +/- 4 mm Hg, P =.04) and increased plasma renin activity (1.2 +/- 0.4 vs 2.7 +/- 0.5 ng/mL/h, P =.001). There was a significant increase in L-selectin expression on monocytes (86 +/- 6 vs 118 +/- 10 MESF units, P =.007), lymphocytes (52 +/- 10 vs 79 +/- 8, P =.01), and granulocytes (124 +/- 7 vs 156 +/- 18, P =.056). However, there were no changes in the other leukocyte and serum adhesion molecules or CRP.

CONCLUSIONS

These findings suggest that AT1 receptor antagonism selectively modulates L-selectin expression on leukocytes and that endogenous stimulation of AT1 receptors by the RAS contributes to the activation of leukocytes and decreased expression of L-selectin in CAD.

Angiotensin II activates the GFAT promoter in mesangial cells

Expression of glutamine:fructose-6-phosphate amidotransferase (GFAT), the rate-limiting enzyme for glucose entry into the hexosamine pathway, is transcriptionally regulated. Immunohistochemical studies of human kidney biopsies demonstrate increased GFAT expression in diabetic glomeruli, but the mechanism responsible for this overexpression is unknown. Given the role of ANG II in diabetic kidney disease, we chose to study the effect of ANG II on GFAT promoter activity in mesangial cells (MC). Exposure of MC to ANG II (10(-7) M) increased GFAT promoter activity (2.5-fold), mRNA (3-fold), and protein (1.6-fold). ANG II-mediated GFAT promoter activation was inhibited by the ANG II type I receptor antagonist candesartan (10(-8) M) but was unaffected by the ANG II type II receptor antagonist PD-123319 (10(-8) M). The intracellular calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (10(-6) M), protein kinase C (PKC) inhibitors bisindoylmaleimide-4 (10(-6) M) and calphostin C (10(-7) M), protein tyrosine kinase (PTK) inhibitor genistein (10(-4) M), Src family kinase inhibitor PP2 (2.5 x 10(-7) M), p42/44 mitogen-activated protein kinase (MAPK) inhibitor PD-98059 (10(-5) M), and the epidermal growth factor (EGF) inhibitor AG-1478 all attenuated GFAT promoter activation by ANG II. We conclude that the GFAT promoter is activated by ANG II via the AT1 receptor. Promoter activation is calcium dependent and PKC dependent but also involves PTK signaling pathways including Src, the EGF receptor, and p42/44 MAPK.

Proinflammatory actions of angiotensins

Many experimental data have suggested that the renin-angiotensin system participates in immune and inflammatory responses. Angiotensin II is involved in several steps of the inflammatory process: mononuclear cells respond to angiotensin II stimulation (cell proliferation and chemotaxis); angiotensin II regulates the recruitment of proinflammatory cells into the site of injury (mediated by the expression of vascular permeability factors, adhesion molecules and chemokines by resident cells); inflammatory cells can produce angiotensin II, and might therefore contribute to the perpetuation of tissue damage. In this review, we summarize the proinflammatory properties of angiotensin II, to demonstrate the novel role of this vasoactive peptide as a true cytokine. We will show the information obtained as a result of the pharmacological blockade of the renin angiotensin system, which has demonstrated that this system is involved in immune and inflammatory diseases. In this aspect, we discuss the molecular mechanism of angiotensin II-induced tissue damage, as well as its contribution to the pathogenesis of several diseases, including atherosclerosis, hypertension and renal damage, showing that angiotensin II plays an active role in the inflammatory response of these diseases.

Endothelial dysfunction in small resistance arteries of patients with non-insulin-dependent diabetes mellitus

OBJECTIVE

Arterial hypertension is frequently associated with the presence of endothelial dysfunction in human subcutaneous small resistance arteries, as evaluated by responses to acetylcholine or bradykinin; however it is not known whether patients with diabetes mellitus show similar alterations. Therefore, we have investigated endothelial function in subcutaneous arteries of normotensive subjects (NT), of patients with essential hypertension (EH), of patients with non-insulin-dependent diabetes mellitus (NIDDM), as well as of patients with both essential hypertension and non-insulin-dependent diabetes mellitus (NIDDM+EH).

PATIENTS AND METHODS

All subjects were submitted to a biopsy of the subcutaneous fat Small arteries were dissected and mounted on a micromyograph. The media to lumen ratio (M/L) was calculated. A concentration-response curve to acetylcholine, to bradykinin as well as to the endothelium-independent vasodilator sodium nitroprusside were performed. We also evaluated the contractile response to endothelin-1. Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) plasma levels were also measured.

RESULTS

The vasodilatation to acetylcholine and bradykinin (but not to sodium nitroprusside) was significantly and similarly reduced in EH, in NIDDM, and in NIDDM+EH compared with NT. The contractile response to endothelin-1 was similarly reduced in EH, in NIDDM and in NIDDM+EH. Plasma ICAM-1 and VCAM-1 concentrations were higher in EH, NIDDM and NIDDM+EH than in NT.

CONCLUSIONS

An evident endothelial dysfunction was detected in patients with NIDDM, and the simultaneous presence of EH did not seem to exert an additive effect. The contractile responses to endothelin-1 were reduced possibly as a consequence of ET(A) receptor down-regulation.