State-of-the-Art lecture. Statins and blockers of the renin-angiotensin system: vascular protection beyond their primary mode of action

Role of whey protein in vascular function: a systematic review and meta-analysis of human intervention studies

Whey protein (WP) has been heavily appreciated as a rich source of bioactive peptides, with potential benefits for cardiovascular health. This study constitutes a systematic review and meta-analysis summarising the effects of WP consumption on vascular reactivity, arterial stiffness and circulatory biomarkers of vascular function. We searched electronic databases, including PubMed, SCOPUS and Web of science for relevant articles from inception to July 2020. Original clinical trials published in English-language journals that investigated the effects of WP on vascular function were eligible. A total of 720 records were identified in the initial search; from these, sixteen were included in our systematic review and thirteen in meta-analysis. The pooled analysis of six studies showed a significant increase in flow-mediated dilation (FMD) after WP consumption (weighted mean differences (WMD): 1·09 %, 95 % CI: 0·17, 2·01, P= 0·01). Meta-analysis of available data did not show any significant reduction in arterial stiffness measures including augmentation index (effect sizes: 7, WMD: -0·29 %, 95 % CI: -1·58, 0·98, P= 0·64) and pulse wave velocity (effect sizes: 4, WMD: -0·72 m/s, 95 % CI: -1·47, 0·03, P= 0·06). Moreover, the pooled analysis of six effect sizes showed no significant effects on plasma levels of nitric oxide following WP supplementation (WMD: 0·42 μmol/l, 95 % CI: -0·52, 1·36, P= 0·38). The overall results provided evidence supporting a protective effect of WP on endothelial function measured by FMD, but not for arterial stiffness measures and circulatory biomarker of vascular function. Further research is required to substantiate the benefits of WP on vascular function.

Age- and Genotype-Specific Effects of the Angiotensin-Converting Enzyme Inhibitor Lisinopril on Mitochondrial and Metabolic Parameters in Drosophila melanogaster

The angiotensin-converting enzyme (ACE) is a peptidase that is involved in the synthesis of Angiotensin II, the bioactive component of the renin-angiotensin system. A growing body of literature argues for a beneficial impact of ACE inhibitors (ACEi) on age-associated metabolic disorders, mediated by cellular changes in reactive oxygen species (ROS) that improve mitochondrial function. Yet, our understanding of the relationship between ACEi therapy and metabolic parameters is limited. Here, we used three genetically diverse strains of Drosophila melanogaster to show that Lisinopril treatment reduces thoracic ROS levels and mitochondrial respiration in young flies, and increases mitochondrial content in middle-aged flies. Using untargeted metabolomics analysis, we also showed that Lisinopril perturbs the thoracic metabolic network structure by affecting metabolic pathways involved in glycogen degradation, glycolysis, and mevalonate metabolism. The Lisinopril-induced effects on mitochondrial and metabolic parameters, however, are genotype-specific and likely reflect the drug's impact on nutrient-dependent fitness traits. Accordingly, we found that Lisinopril negatively affects survival under nutrient starvation, an effect that can be blunted by genotype and age in a manner that partially mirrors the drug-induced changes in mitochondrial respiration. In conclusion, our results provide novel and important insights into the role of ACEi in cellular metabolism.

Adjunctive therapy with statins reduces residual albuminuria/proteinuria and provides further renoprotection by downregulating the angiotensin II-AT1 pathway in hypertensive nephropathy

OBJECTIVES

Blockade of the renin-angiotensin II (Ang II) system by AT1 blockers (ARBs) and angiotensin-converting enzyme inhibitors retards the progression of chronic kidney disease (CKD) by reducing albuminuria/proteinuria. However, many patients with CKD suffer from residual albuminuria/proteinuria, which is an independent risk factor for CKD progression. The aim of the current study is to investigate the effect of pitavastatin, one of the adjunctive agents to ARBs, on the reduction of albuminuria/proteinuria and further renoprotection mediated by telmisartan in spontaneously hypertensive rats.

METHODS AND RESULTS

Forty-two-week-old spontaneously hypertensive rats were grouped randomly and received 8 weeks of treatments with vehicle, telmisartan, pitavastatin or a combination of telmisartan and pitavastatin. Both albuminuria and proteinuria were inhibited significantly in the telmisartan-treated group, but an obviously residual albuminuria was maintained. The combination treatment with telmisartan and pitavastatin displayed a more effective decrease in albuminuria and proteinuria, even to the normal level. Enhanced nephroprotection was also observed in this combination group, which was independent of the cholesterol-lowering effects. Further mechanistic studies revealed that the combination therapy greatly attenuated the expression of intrarenal Ang II and AT1, thereby decreasing the activation of TGF-β-Smad and NF-κB and inhibiting fibrosis and inflammation.

CONCLUSION

Adjunctive therapy with pitavastatin dramatically reduced residual albuminuria/proteinuria and enhanced nephroprotection, likely by downregulating the expression of intrarenal Ang II and AT1. It could be concluded that statins might be a promising adjunctive therapeutic agent to conventional ARB treatment in hypertensive renal damage.

Danish trends in pharmacotherapy, comorbidities, and demographics in patients referred for coronary angiography: what changed during a decade?

AIMS

Coronary angiography holds a central role in the diagnosis of coronary heart disease. We studied temporal trends in referral patterns 2000-09.

METHODS AND RESULTS

We identified 156 496 first-time coronary angiographies in 2000-09 in nationwide registries. Trends were analyzed in 2-year intervals. Numbers of acute (5943-10 707) and elective (17 294-25 550) procedures increased between 2000-01 and 2008-09. Mean age increased from 61.8 to 63.9 years (P < 0.001) and the proportion of females increased from 33 to 37% (P < 0.001). An increase in the number of patients with prior chronic heart failure (2866 vs. 3197), cerebrovascular disease (1790 vs. 2906), diabetes (2527 vs. 4593), and arrhythmias (2985 vs. 4733) was observed. The proportion of acute patients examined the same day as hospitalized increased from 56.6 to 83.1%. Odds ratios (95% confidence interval) for treatment with statins [3.42(3.27;3.57)], RAS-inhibitors [1.85(1.77;1.93)], and acetylsalicylic acid [1.43(1.37;1.49)] at the time of coronary angiography increased towards 2008-09. Elective patients received medical treatment more often than acute patients (P < 0.001).

CONCLUSION

During a 10-year period, there was an increase in the mean age of patients and the proportion of female patients, and a 56% increase in number of coronary angiographies performed. The use of prophylactic cardiovascular drugs among these high-risk patients increased during our study period.

Endothelial dysfunction in conduit arteries and in microcirculation. Novel therapeutic approaches

The vascular endothelium not only is a single monolayer of cells between the vessel lumen and the intimal wall, but also plays an important role by controlling vascular function and structure mainly via the production of nitric oxide (NO). The so called "cardiovascular risk factors" are associated with endothelial dysfunction, that reduces NO bioavailability, increases oxidative stress, and promotes inflammation contributing therefore to the development of atherosclerosis. The significant role of endothelial dysfunction in the development of atherosclerosis emphasizes the need for efficient therapeutic interventions. During the last years statins, angiotensin-converting enzyme inhibitors, angiotensin-receptor antagonists, antioxidants, beta-blockers and insulin sensitizers have been evaluated for their ability to restore endothelial function (Briasoulis et al., 2012). As there is not a straightforward relationship between therapeutic interventions and improvement of endothelial function but rather a complicated interrelationship between multiple cellular and sub-cellular targets, research has been focused on the understanding of the underlying mechanisms. Moreover, the development of novel diagnostic invasive and non-invasive methods has allowed the early detection of endothelial dysfunction expanding the role of therapeutic interventions and our knowledge. In the current review we present the available data concerning the contribution of endothelial dysfunction to atherogenesis and review the methods that assess endothelial function with a view to understand the multiple targets of therapeutic interventions. Finally we focus on the classic and novel therapeutic approaches aiming to improve endothelial dysfunction and the underlying mechanisms.

Limb salvage in women

The prevalence of peripheral arterial occlusive disease (PAD) in women and men is equal. Studies to date present conflicting data of gender effects on the risk factors, clinical presentation, and treatment outcomes. Clinical trials have often failed to analyze results by gender or to recruit sufficient women to enable such an analysis. This review summarizes the management and outcome of limb salvage therapy with a particular focus in women.

Improvement of arterial wall characteristics by the low-dose fluvastatin and valsartan combination in type 1 diabetes mellitus patients

We tested whether short-term, low-dose treatment with the fluvastatin and valsartan combination could improve impaired arterial wall characteristics in type 1 diabetes mellitus patients. A total of 44 type 1 diabetes mellitus patients were randomised into the treatment group [n = 22; received a low-dose combination of fluvastatin (10 mg daily) and valsartan (20 mg daily)] and the control group (n = 22; received placebo), both for 30 days. Brachial artery flow-mediated dilation (FMD), pulse wave velocity (PWV) and carotid artery β-stiffness were measured. Significant improvements in FMD (+73.2%), PWV (-7.5%) and β-stiffness (-10.0%) were achieved after 1-month treatment compared to the control group (all p values < 0.001). Three months after therapy discontinuation, important residual improvement in measured parameters was still present. No changes in lipids and blood pressure accompanied the beneficial improvements. We conclude that relatively simple intervention (low-dose, short-term fluvastatin/valsartan combination) produces substantial, long-term improvement of arterial wall characteristics in type 1 diabetes mellitus patients.

Treatment With Low-dose Atorvastatin, Losartan, and Their Combination Increases Expression of Vasoactive-Related Genes in Rat Aortas

Recently it has been shown that statins and angiotensin receptor blockers (ARBs) at low doses express beneficial pleiotropic vascular effects. We aimed to explore whether these drugs at low doses induce the expression of vasoactive-related genes. Sixty adult Wistar rats were treated with low-dose atorvastatin (2 mg/kg), low-dose losartan (5 mg/kg), their combination or saline daily for 4, 6, or 8 weeks. Expression of the vasoactive-related genes endothelin receptor type A ( EDNRA), endothelial nitric oxide synthase 3 ( NOS3), inducible nitric oxide synthase 2 ( NOS2), and angiotensin II receptor type 1 ( AGTRL1a) was measured in isolated thoracic aortas. Expression of EDNRA gradually decreased, the lowest values being obtained after 8 weeks (low-dose atorvastatin, losartan [1.6- and 1-7-fold vs controls, respectively; both P < .05], and the combination [2.3-fold vs control, P < .001]). The highest values of NOS3 were obtained after 6 weeks (low-dose atorvastatin, losartan, and their combination, 3.1-fold, P < .01; 3.4-fold, P < .001; and 3.6-fold, P < .001 vs controls, respectively) and then declined after 8 weeks. The combination was more effective in inducing total NOS3 expression when compared to the separate drugs (1.4-fold; P < .05). Importantly, expression of NOS3 was associated with increased plasma NO levels and positively correlated with thoracic aorta relaxation. No changes in expression of NOS2 and AGTRL1a were observed. We showed that low-dose atorvastatin or losartan and especially their combination increases the expression of NOS3 and decreases the expression of EDNRA. These findings are valuable in explaining the effectiveness of the “low-dose pharmacological approach” for improvement in arterial function.

Acute effects of ingestion of a novel whey-derived extract on vascular endothelial function in overweight, middle-aged men and women

Whey protein intake reduces CVD risk, but little is known whether whey-derived bioactive peptides regulate vascular endothelial function (VEF). We determined the impact of a whey-derived extract (NOP-47) on VEF in individuals with an increased cardiovascular risk profile. Men and women with impaired brachial artery flow-mediated dilation (FMD) (n 21, age 55 (sem 1·3) years, BMI 27·8 (sem 0·6) kg/m2, FMD 3·7 (sem 0·4) %) completed a randomised, cross-over study to examine whether ingestion of NOP-47 (5 g) improves postprandial VEF. Brachial artery FMD, plasma amino acids, insulin, and endothelium-derived vasodilators and vasoconstrictors were measured for 2 h after ingestion of NOP-47 or placebo. Acute NOP-47 ingestion increased FMD at 30 min (4·6 (sem 0·5) %) and 120 min (5·1 (sem 0·5) %) post-ingestion (P< 0·05, time × trial interaction), and FMD responses at 120 min were significantly greater in the NOP-47 trial compared with placebo (4·3 (sem 0·5) %). Plasma amino acids increased at 30 min following NOP-47 ingestion (P< 0·05). Serum insulin increased at 15, 30 and 60 min (P< 0·001) following NOP-47 ingestion. No changes were observed between the trials for plasma NO∙ and prostacyclin metabolites or endothelin-1. Ingestion of a rapidly absorbed extract derived from whey protein improved endothelium-dependent dilation in older adults by a mechanism independent of changes in circulating vasoactive compounds. Future investigation is warranted in individuals at an increased CVD risk to further elucidate potential health benefits and the underlying mechanisms of extracts derived from whey.

Peripheral arterial disease of the lower extremities

Persons with peripheral arterial disease (PAD) are at increased risk for all-cause mortality, cardiovascular mortality, and mortality from coronary artery disease. Smoking should be stopped and hypertension, dyslipidemia, diabetes mellitus, and hypothyroidism treated. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in persons with PAD and hypercholesterolemia. The serum low-density lipoprotein cholesterol should be reduced to < 70 mg/dl. Antiplatelet drugs such as aspirin or clopidogrel, angiotensin-converting enzyme inhibitors, and statins should be given to persons with PAD. β-Blockers should be given if coronary artery disease is present. Cilostazol improves exercise time until intermittent claudication. Exercise rehabilitation programs should be used. Revascularization should be performed if indicated.

A Randomized Placebo Controlled Trial of Early Treatment of Acute Ischemic Stroke with Atorvastatin and Irbesartan

Background

Cholesterol and blood pressure lowering therapies are effective in the secondary prevention of ischemic stroke.

Aim

To determine whether 30 days of treatment with atorvastatin, or irbesartan, initiated within 96 h of symptom onset improves recovery from acute ischemic stroke.

Methods

Eighty-one patients with acute ischemic stroke participated in this double-blind, placebo-controlled, randomized trial of atorvastatin (80 mg) vs. placebo, and/or irbesartan (150 mg) vs. placebo. Fifty-two patients (randomized 53 ± 22 h after onset of symptoms) completed the 30-day primary outcome follow-up.

Results

The primary outcome, maximal brain infarct size at days 3 and 30 measured by perfusion computed tomography, was not significantly altered by random assignment to irbesartan (1088 (IQR 216, 2594) mm2 at day 3, compared with 398 (144, 2053) mm2 among the placebo group, P=0·79 controlling for baseline values; and 822 (159, 1717) mm2 at day 30, cf 280 (76, 1330) mm2; P=0·63); or atorvastatin (454 (107, 1765) mm2 cf 825 (265, 2509) mm2 at day 3; P=0·33; and 462 (43, 1399) mm2 cf 280 (128, 1559) mm2 at day 30, P=0·79). There were no other significant differences among the treatment groups with the exception of: • high sensitivity C-reactive protein concentrations, which were lower in the irbesartan treatment group at day 30 (mean difference 12·6 mg/L; 95% CI: −25·1, −0·1; P=0·048); and • the mean cerebral blood flow in the affected cerebral hemisphere at 30 days after stroke, which was significantly reduced by random assignment to irbesartan compared with placebo in both the affected cerebral hemisphere (−7·5 mL/100 mL/min (95% CI: −1·7 to −13·4, P=0·01)) and in the unaffected hemisphere (−7·3 mL/100 mL/min (95% CI: −1·3, −13·4; P=0·02)). Atorvastatin therapy was well tolerated, but irbesartan therapy was associated with an increased rate of withdrawal from therapy ( n=10 (29%), compared with n=3 (9%) who withdrew from placebo, P=0·04).

Conclusions

Treatment with atorvastatin and irbesartan, initiated on day 3 after acute ischemic stroke, did not appear to substantially modify infarct growth.

Effects of whey protein supplements on metabolism: evidence from human intervention studies

PURPOSE OF REVIEW

Epidemiological studies indicate that the consumption of milk and dairy products is inversely associated with a lower risk of metabolic disorders and cardiovascular diseases. In particular, whey protein seems to induce these effects because of bioactive compounds such as lactoferrin, immunoglobulins, glutamine and lactalbumin. In addition, it is an excellent source of branch chained amino acids. This review summarizes recent findings on the effects of whey protein on metabolic disorders and the musculoskeletal system.

RECENT FINDINGS

We identified 25 recently published intervention trials examining chronic and/or acute effects of whey protein supplementation on lipid and glucose metabolism, blood pressure, vascular function and on the musculoskeletal system. Whey protein appears to have a blood glucose and/or insulin lowering effect partly mediated by incretins. In addition, whey protein may increase muscle protein synthesis. In contrast there are no clear-cut effects shown on blood lipids and lipoproteins, blood pressure and vascular function. For bone metabolism the data are scarce.

SUMMARY

In summary, whey protein may affect glucose metabolism and muscle protein synthesis. However, the evidence for a clinical efficacy is not strong enough to make final recommendations with respect to a specific dose and the duration of supplementation.

Salidroside protects against hydrogen peroxide-induced injury in cardiac H9c2 cells via PI3K-Akt dependent pathway

Oxidative stress induces serious tissue injury in cardiovascular diseases. Salidroside, with its strong antioxidative and cytoprotective actions, is of particular interest in the development of antioxidative therapies for oxidative injury in cardiac diseases. We examined the pharmacological effects of salidroside on H9c2 rat cardiomyoblast cells under conditions of oxidative stress induced by hydrogen peroxide (H2O2) challenge. Salidroside attenuated H2O2-impaired cell viability in a concentration-dependent manner, and effectively inhibited cellular malondialdehyde production, lethal sarcolemmal disruption, cell necrosis, and apoptosis induced by H2O2 insult. Salidroside significantly augmented Akt phosphorylation at Serine 473 in the absence or presence of H2O2 stimulation; wortmannin, a specific inhibitor of PI3K, abrogated salidroside protection. Salidroside increased the intracellular mRNA expression and activities of catalase and Mn-superoxide dismutases in a PI3K-dependent manner. Our results indicated that salidroside protected cardiomyocytes against oxidative injury through activating the PI3K/Akt pathway and increasing the expression and activities of endogenous PI3K dependent antioxidant enzymes.

ACE up the sleeve - are vascular patients medically optimized?

Objective

To examine the current medical management of arteriopathic patients attending a vascular surgical service at a university teaching hospital over a 6-month period. The prescribing of antiplatelets, statins, angiotensin-converting enzyme (ACE) inhibitors, or angiotensin receptor blockers and beta-blockers was specifically examined. Vascular patients are often under the care of multiple specialties, and therefore the influence of different medical specialties on the patients’ medical management was also examined.

Design

Between January and June 2009, data were recorded on sequential patients with arterial disease attending the vascular surgical service. Patients’ demographics, type of arterial disease, medical consultations within the previous 12 months, and current medications were recorded.

Results

The study included 180 patients with a mean age of 69 years (39–88 years). All but 4% were taking an antiplatelet or anticoagulant, predominantly aspirin. There were 86% taking a statin, 44% taking a beta-blocker, and 51% taking an ACE inhibitor. Suboptimal prescription of ACE inhibitors and beta-blockers was evident regardless of the type of medical consultations in the previous year. No specialty group differed significantly from vascular surgeons in their prescribing pattern.

Conclusions

While almost all arteriopaths receive some form of antiplatelet and statin in line with clinical evidence, ACE inhibitors and beta-blockers appear to be under-prescribed in this arteriopathic population. We conclude that opportunity exists for vascular surgeons to embrace recent guidelines and lead the way in both surgical and medical optimization of arteriopathic patients through improving links with primary care physicians or taking greater responsibility themselves for the medical as well as the surgical care of their arteriopathic patients.

Statins in hypertension: are they a new class of antihypertensive agents?

High blood pressure is a very common disease in hypercholesterolemic and diabetic patients and contributes to the increase in cardiovascular risk. Inhibitors of 3OH-3methyl-glutaryl-coenzyme A reductase are the most effective and widely used cholesterol-lowering drugs. They significantly reduce the risk of cardiovascular events and death in both primary and secondary prevention of cardiovascular disease. Although the long-term benefit by statin treatment is largely attributed to their cholesterol-lowering action, increasing attention focuses on additional actions called "pleitropic effects" that might explain the cardiovascular protection seen shortly after the initiation of therapy. Very few and small studies have investigated the antihypertensive effect of statins in patients with hypertension associated with hypercholesterolemia, and the results of recently published large statin studies (albeit not designed to answer this question) have attracted the interest on this subject. Many other studies, also not specifically aimed at the evaluation of the statins' antihypertensive effect, have provided information concerning changes in blood pressure during treatment with statins, but severe limitations such as inadequate study design, small or very small sample size, too short of a treatment period, and modification of concomitant antihypertensive therapy have prevented finding a definitive effect on blood pressure. From the available results, it appears consistent that statins may be useful in hypertensives with high serum total cholesterol, in those whose hypertension is not well controlled with antihypertensive agents even without high serum total cholesterol, in hypertensive subjects well controlled with antihypertensives without high serum cholesterol when they have high polymerase chain reaction levels, in those who require preventive measures because of other concomitant cardiovascular risk factors, or when they require secondary prevention. Future research could further characterize the impact of statin use alone or in combination with antihypertensive agents to delay the development of Stage 1 hypertension in prehypertension.

Effect of pravastatin on ventricular arrhythmias in infarcted rats: role of connexin43

Epidemiologic studies showed that men treated with statins appear to have a lower incidence of sudden death than men without statins. However, the specific factor for this remained disappointingly elusive. We assessed whether pravastatin enhanced connexin43 expression after myocardial infarction through attenuation of endothelin-1. Twenty-four hours after ligation of the anterior descending artery, male Wistar rats were randomized to vehicle, pravastatin, mevalonate, bosentan, or a combination of pravastatin and mevalonate or pravastatin and bosentan for 4 wk. Myocardial endothelin-1 levels were significantly elevated in vehicle-treated rats at the border zone compared with sham-operated rats. Myocardial connexin43 expression at the border zone was significantly decreased in vehicle-treated infarcted rats compared with sham-operated rats. Attenuated connexin43 expression was blunted after administration of pravastatin, as assessed by immunofluorescence analysis, Western blotting, and real-time quantitative RT-PCR of connexin43. Bosentan enhanced connexin43 amount in infarcted rats and did not have additional beneficial effects on pravastatin-treated rats. Arrhythmic scores during programmed stimulation in vehicle-treated rats were significantly higher than scores in those treated with pravastatin. In contrast, the beneficial effects of pravastatin-induced connexin43 were abolished by the addition of mevalonate and a protein kinase C inducer. In addition, the amount of connexin43 showed significant increase after addition of bisindolylmaleimide, implicating that protein kinase C is a relevant target in endothelin-1-mediated connexin43 expression. Thus chronic use of pravastatin after infarction, resulting in enhanced connexin43 amount by attenuation of mevalonate-dependent endothelin-1 through a protein kinase C-dependent pathway, may attenuate the arrhythmogenic response to programmed electrical stimulation.

Peripheral arterial disease in women

Peripheral arterial disease (PAD) is chronic arterial occlusive disease of the lower extremities caused by atherosclerosis whose prevalence increases with age. Only one-half of women with PAD are symptomatic. Symptomatic and asymptomatic women with PAD are at increased risk for all-cause mortality, cardiovascular mortality, and mortality from coronary artery disease. Modifiable risk factors that predispose women to PAD include active cigarette smoking, passive smoking, diabetes mellitus, hypertension, dyslipidemia, increased plasma homocysteine levels and hypothyroidism. With regard to management, women who smoke should be encouraged to quit and referred to a smoking cessation program. Hypertension, diabetes mellitus, dyslipidemia, and hypothyroidism require treatment. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in women with PAD and hypercholesterolemia. Anti-platelet drugs such as aspirin or especially clopidogrel, angiotensin-converting enzyme inhibitors and statins should be given to all women with PAD. Beta blockers are recommended if coronary artery disease is present. Exercise rehabilitation programs and cilostazol increase exercise time until intermittent claudication develops. Chelation therapy should be avoided as it is ineffective. Indications for lower extremity percutaneous transluminal angioplasty or bypass surgery in women are (1) incapacitating claudication interfering with work or lifestyle; and (2) limb salvage in women with limb-threatening ischemia as manifested by rest pain, non-healing ulcers, and/or infection or gangrene. Future research includes investigation of mechanisms underlying why women have a higher risk of graft failure and major amputation.

Acute ingestion of a novel whey-derived peptide improves vascular endothelial responses in healthy individuals: a randomized, placebo controlled trial

Background

Whey protein is a potential source of bioactive peptides. Based on findings from in vitro experiments indicating a novel whey derived peptide (NOP-47) increased endothelial nitric oxide synthesis, we tested its effects on vascular function in humans.

Methods

A randomized, placebo-controlled, crossover study design was used. Healthy men (n = 10) and women (n = 10) (25 ± 5 y, BMI = 24.3 ± 2.3 kg/m²) participated in two vascular testing days each preceded by 2 wk of supplementation with a single dose of 5 g/day of a novel whey-derived peptide (NOP-47) or placebo. There was a 2 wk washout period between trials. After 2 wk of supplementation, vascular function in the forearm and circulating oxidative stress and inflammatory related biomarkers were measured serially for 2 h after ingestion of 5 g of NOP-47 or placebo. Macrovascular and microvascular function were assessed using brachial artery flow mediated dilation (FMD) and venous occlusion strain gauge plethysmography.

Results

Baseline peak FMD was not different for Placebo (7.7%) and NOP-47 (7.8%). Placebo had no effect on FMD at 30, 60, and 90 min post-ingestion (7.5%, 7.2%, and 7.6%, respectively) whereas NOP-47 significantly improved FMD responses at these respective postprandial time points compared to baseline (8.9%, 9.9%, and 9.0%; P < 0.0001 for time × trial interaction). Baseline reactive hyperemia forearm blood flow was not different for placebo (27.2 ± 7.2%/min) and NOP-47 (27.3 ± 7.6%/min). Hyperemia blood flow measured 120 min post-ingestion (27.2 ± 7.8%/min) was unaffected by placebo whereas NOP-47 significantly increased hyperemia compared to baseline (29.9 ± 7.8%/min; P = 0.008 for time × trial interaction). Plasma myeloperoxidase was increased transiently by both NOP-47 and placebo, but there were no changes in markers inflammation. Plasma total nitrites/nitrates significantly decreased over the 2 hr post-ingestion period and were lower at 120 min after placebo (-25%) compared to NOP-47 (-18%).

Conclusion

These findings indicate that supplementation with a novel whey-derived peptide in healthy individuals improves vascular function.

Established and newly proposed mechanisms of chronic cyclosporine nephropathy

Cyclosporine (CsA) has improved patient and graft survival rates following solid-organ transplantation and has shown significant clinical benefits in the management of autoimmune diseases. However, the clinical use of CsA is often limited by acute or chronic nephropathy, which remains a major problem. Acute nephropathy depends on the dosage of CsA and appears to be caused by a reduction in renal blood flow related to afferent arteriolar vasoconstriction. However, the mechanisms underlying chronic CsA nephropathy are not completely understood. Activation of the intrarenal renin-angiotensin system (RAS), increased release of endothelin-1, dysregulation of nitric oxide (NO) and NO synthase, up-regulation of transforming growth factor-beta1 (TGF-beta1), inappropriate apoptosis, stimulation of inflammatory mediators, enhanced innate immunity, endoplasmic reticulum stress, and autophagy have all been implicated in the pathogenesis of chronic CsA nephropathy. Reducing the CsA dosage or using other renoprotective drugs (angiotensin II receptor antagonist, mycophenolate mofetil, and statins, etc.) may ameliorate chronic CsA-induced renal injury. This review discusses old and new concepts in CsA nephropathy and preventive strategies for this clinical dilemma.

Statin use and risk of prostate cancer: results from a population-based epidemiologic study

Epidemiologic studies of statin use in relation to prostate cancer risk have been inconclusive. Recent evidence, however, suggests that longer-term use may reduce risk of more advanced disease. The authors conducted a population-based study of 1,001 incident prostate cancer cases diagnosed in 2002-2005 and 942 age-matched controls from King County, Washington, to evaluate risk associated with statin use. Logistic regression was used to generate odds ratios for ever use, current use, and duration of use. No overall association was found between statin use and prostate cancer risk (odds ratio (OR) = 1.0, 95% confidence interval (CI): 0.8, 1.2 for current use; OR = 1.1, 95% CI: 0.7, 1.8 for >10 years' use), even for cases with more advanced disease. Risk related to statin use, however, was modified by body mass index (interaction p = 0.04). Obese men (BMI > or =30 kg/m2) who used statins had an increased risk (OR = 1.5, 95% CI: 1.0, 2.2) relative to obese nonusers, with a stronger association for longer-term use (OR = 1.8, 95% CI: 1.1, 3.0 for > or =5 years' use). Although statin use was not associated with overall prostate cancer risk, the finding of an increased risk associated with statin use among obese men, particularly use for extended durations, warrants further investigation.

Multiorgan-protective actions of blockers of the renin-angiotensin system, statins and erythropoietin: common pleiotropic effects in reno-, cardio- and neuroprotection

Renal diseases induce nephroprotective measures that may affect the heart, brain and other organs. In addition, many cardiovascular and neurological diseases are accompanied by renal lesions. For these reasons, multiorgan-protective measures, including cardio-, reno- and neuro-protective measures, are necessary to treat these diseases. The drugs used in nephrology are often pleiotropic. Although they usually address a single organ or tissue, many of them have complex actions that may provide multiorgan-protection. The present paper aims to review 3 classes of drugs that are commonly prescribed in nephrological practice: statins, RAS blockers (such as ACEIs and ARBs) and erythropoietin (EPO). This paper highlights the renoprotective actions, as well as those that are protective of the heart, brain and other organs, of these drugs at the cellular and molecular level. Their protective actions are attributable to their main effects and pleiotropic effects. The protective pleiotropic actions of these drugs may be exerted on multiple organs, making them multiorgan-protective. Another objective is to analyse the shared multiorgan-protective pleiotropic effects of RAS blockers (ACEIs and ARBs), statins and erythropoietin. This will allow for the practical association of the main renoprotective drugs with multiorgan protection.

Management of peripheral arterial disease of the lower extremities

Smoking should be stopped and hypertension, diabetes mellitus, dyslipidemia, and hypothyroidism treated in patients with peripheral arterial disease (PAD) of the lower extremities. Statins decrease the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in persons with PAD and hypercholesterolemia. Antiplatelet drugs such as aspirin or clopidogrel, especially clopidogrel, angiotensin-converting enzyme inhibitors, and statins should be given to all persons with PAD. Beta blockers should be given if coronary artery disease is present. Exercise rehabilitation programs and cilostazol increase exercise time until intermittent claudication develops. Chelation therapy should be avoided. Indications for lower extremity percutaneous transluminal angioplasty or bypass surgery are (1) incapacitating claudication in persons interfering with work or lifestyle, (2) limb salvage in persons with limb-threatening ischemia as manifested by rest pain, nonhealing ulcers, and/or infection or gangrene, and (3) vasculogenic impotence.

Translational approaches for the prevention of estrogen receptor-negative breast cancer

Breast cancer prevention has focused heavily on endocrine interventions using selective estrogen receptor modulators and aromatase inhibitors. Tamoxifen, the stereotypical selective estrogen receptor modulator, significantly reduces the breast cancer incidence in high-risk women. Selective estrogen receptor modulators and aromatase inhibitors, however, only prevent the development of estrogen receptor-positive breast cancer and have no effect in reducing the risk of estrogen receptor-negative breast cancer, which has poor prognosis. Thus, preventive therapies for estrogen receptor-negative breast cancer are clearly needed. Recently, a number of novel chemopreventive agents targeting nonendocrine pathways have been developed and shown to prevent estrogen receptor-negative mammary tumorigenesis in animal models. These agents include rexinoids, selective cyclooxygenase-2 inhibitors, tyrosine kinase inhibitors, and others. In this review, we discuss the effects of selective estrogen receptor modulators and aromatase inhibitors, as well as novel agents targeting nonendocrine pathways. We also discuss the promise of combining these agents for the effective prevention of all forms of breast cancer.

Insulin resistance, oxidative stress, and podocyte injury: role of rosuvastatin modulation of filtration barrier injury

BACKGROUND/AIM

There is an emerging relationship between insulin resistance/hyperinsulinemia, oxidative stress, and glomerular injury manifesting as albuminuria. HMG-CoA reductase inhibitors (statins) have been shown to reduce oxidative stress in the vasculature as well as albuminuria in animal models and in human studies. The glomerular filtration barrier is emerging as a critical determinant of albumin filtration. We investigated the effects of insulin resistance and rosuvastatin or placebo on the glomerular filtration barrier.

METHOD

Young Zucker obese and Zucker lean rats (6-7 weeks old) were treated with the HMG-CoA reductase inhibitor rosuvastatin (10 mg/kg/day) or placebo for 21 days.

RESULTS

In the Zucker obese rats, homeostasis model assessment-insulin resistance index, oxidative markers (NADPH oxidase activity, reactive oxygen species, and urine isoprostane formation), podocyte foot process effacement, and albuminuria were increased as compared with Zucker lean controls, independent of increases in systolic blood pressure. Albuminuria correlated with podocyte foot process effacement (r(2) = 0.61) and insulin level (r(2) = 0.69). Rosuvastatin treatment improved albuminuria, filtration barrier indices, and oxidative stress via copper/zinc superoxide dismutase.

CONCLUSIONS

These data indicate that hyperinsulinemia together with insulin resistance is associated with podocyte injury and albuminuria independent of the systolic blood pressure. Further, rosuvastatin modulates filtration barrier injury and albuminuria and improves oxidative stress measures via copper/zinc superoxide dismutase.

Effect of ScrF I polymorphism in the 2nd intron of the HMGCR gene on lipid-lowering response to simvastatin in Chinese diabetic patients

OBJECTIVE

To investigate whether ScrF I polymorphism in the 2nd intron of the HMG-COA reductase gene (HMGCR) influences serum lipid levels and whether this polymorphism affects the efficiency of the cholesterol lowering HMG-CoA reductase inhibitor, simvastatin.

METHODS

One hundred sixty-eight patients with type 2 diabetes mellitus (T2DM) prospectively received simvastatin as a single-agent therapy (20mg day-1 p.o.) for 12 weeks. Serum lipid levels were determined before and after simvastatin treatment. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

Subjects with the AA homozygotes had significantly higher serum very low-density lipoprotein cholesterol (VLDL-C) levels than those with the aa homozygotes. In addition, in 168 patients with T2DM who took 20mg simvastatin, the VLDL-C lowering effect by simvastatin in subjects with the aa homozygotes was significantly lower than in those with the Aa heterozygotes and AA homozygotes.

CONCLUSIONS

Simvastatin treatment significantly decreased plasma lipids in all patients (P<0.01). Importantly, we demonstrate that ScrF I polymorphism of the HMGCR gene in patients with T2DM groups is associated with significant elevation of serum VLDL-C levels. Subjects with the AA homozygotes had significantly higher serum high VLDL-C levels than those with the Aa heterozygotes and aa homozygotes (AA: 2.18+/-0.51; Aa: 2.04+/-0.59, aa: 1.86+/-0.43, P<0.05 for comparison among three genotypes and P<0.01 for difference between AA and aa). Furthermore, this polymorphism tends to show an enhanced response to an HMG-CoA reductase inhibitor in terms of the cholesterol-lowering effect. In 168 patients with T2DM who took 20mg simvastatin, the VLDL-C lowering effect by simvastatin in subjects with the AA homozygotes was significantly lower than in those with the Aa heterozygotes and aa homozygotes (the reduction in serum VLDL-C levels; 37.03+/-5.67 versus 28.97+/-4.96, P<0.01; 34.62+/-5.87 versus 28.97+/-4.96, P<0.05). These results suggest that the HMGCR gene may serve as a modifier gene for hypercholesterolemia in Chinese diabetic patients.

Effect of Losartan Therapy on Endothelial Function in Hypertensive Patients

The aim of the study was to evaluate the effect of losartan therapy on endothelial function by measuring serum nitric oxide (NO) levels and urinary excretion of NO in patients with essential hypertension. A group of 30 untreated stage 2 hypertensive patients (15 males and 15 females; age, 51.3 +/- 1.5 years) were included in the study. Office systolic and diastolic blood pressure (BP) was measured by using a mercury sphygmomanometer according to phase I and V of Korotkoff sounds. NO levels in serum and 24-hour urine were determined at baseline and after 6 weeks of daily dosing with losartan (50-100 mg). Losartan therapy resulted in a significant fall in systolic/diastolic BP (from 169.7 +/- 4.1/105 +/- 1.8 mm Hg at baseline to 146 +/- 2.7/91 +/- 1.9 mm Hg at the end of losartan treatment; P < 0.001). The therapy also caused significant increases in both serum NO level (32.74 +/- 3.01 microM/L at baseline versus 79.04 +/- 5.17 microM/L; P < 0.001 after therapy) and urinary NO excretion (58.21 +/- 3.72 microM/L at baseline versus 113.21 +/- 8.63 microM/L; P < 0.001 after therapy). Losartan therapy also reduced serum malondialdehyde (MDA), which is a measure of oxidative stress, by 0.201 nM (15.3%; P = 0.009). Losartan at a dose of 50 to 100 mg per day was effective in reducing elevated BP. The increase in serum NO levels and urinary NO excretion and a decrease in serum MDA levels by losartan treatment indicate a reduction in oxidative stress and enhances NO availability, both of which improve endothelial function. Thus, losartan therapy improves endothelial function in hypertensive patients with essential hypertension.

Peripheral arterial disease in the elderly

Smoking should be stopped and hypertension, diabetes mellitus, dyslipidemia, and hypothyroidism treated in elderly patients with peripheral arterial disease (PAD) of the lower extremities. Statins reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in patients with PAD and hypercholesterolemia. Antiplatelet drugs such as aspirin or clopidogrel, especially clopidogrel, angiotensin-converting enzyme inhibitors, and statins should be given to all elderly patients with PAD without contraindications to these drugs. Beta blockers should be given if coronary artery disease is present. Exercise rehabilitation programs and cilostazol increase exercise time until intermittent claudication develops. Chelation therapy should be avoided. Indications for lower extremity percutaneous transluminal angioplasty or bypass surgery are (1) incapacitating claudication in patients interfering with work or lifestyle; (2) limb salvage in patients with limb-threatening ischemia as manifested by rest pain, nonhealing ulcers, and/or infection or gangrene; and (3) vasculogenic impotence.

Pravastatin Inhibits Carboxymethyllysine-Induced Monocyte Chemoattractant Protein 1 Expression in Podocytes via Prevention of Signalling Events

BACKGROUND

Up-regulation of local monocyte chemoattractant protein 1 (MCP-1) production is involved in glomerular damage through macrophage recruitment and activation in diabetic nephropathy. Advanced glycation end-products induced chemokine production in cultured mesangial cells and podocytes. Statins prevented recruitment of macrophages to the glomeruli, suggesting that statins may have the ability of anti-inflammation. In the present studies, we investigated the effects of pravastatin in the carboxymethyllysine (CML)-induced MCP-1 expression in mouse differentiated podocytes.

METHODS

MCP-1 gene and protein expressions were examined using RT-PCR and ELISA. Dichlorofluorescein-sensitive intracellular reactive oxygen species (ROS) generation was measured by confocal microscopy. Activation of extracellular signal-regulated kinase (ERK), nuclear factor (NF) kappaB and Sp1 were studied using Western blotting and immunocytochemistry.

RESULTS

MCP-1 was induced by CML in a time- and dose-dependent manner. CML-induced MCP-1 mRNA and protein production were inhibited by 0.1 or 1 mM pravastatin. CML rapidly generated intracellular ROS in podocytes. Pravastatin did not have any ability of blocking ROS generation. Phosphorylated ERK was found in podocytes incubated with CML and was prevented by pravastatin in a dose-dependent manner. Both Western blotting and immunocytochemistry results suggested that pretreatment of podocytes with pravastatin prevented the CML-induced NF-kappaB and Sp1 translocation.

CONCLUSION

These results suggest that pravastatin prevents CML to induce MCP-1 expression in podocytes via modulation of the intracellular ERK/NF-kappaB and Sp1 signalling pathway.

Optimal medical management of peripheral arterial disease

Patients with peripheral vascular disease are less likely to receive optimal medical management than patients with coronary artery disease. However, early medical treatment is critical because it is profoundly beneficial and the benefits are maximized. Even in patients with advanced disease requiring invasive intervention, medical management has been proven to improve outcome, prolong the success of the intervention, improve functional capacity, and prolong life. The vascular surgeon should be knowledgeable enough to initiate basic medical therapy and to define for their patients the goals that need to be met to optimize their medical management. The vascular surgeon should be instrumental in assuring that the peripheral vascular patient receives medical therapy of the same standard as the patient with coronary disease. The major modifiable risk factors in the vascular patient are: smoking, high blood pressure, hyperlipidemia, physical inactivity, obesity, and diabetes. In addition, the use of beta blockers for patients with coronary disease and antiplatelet therapy as well as angiotensin-converting enzyme (ACE) inhibitors are recommended for all patients with peripheral vascular disease. Statins have favorable effects on multiple interrelated aspects of vascular biology important in atherosclerosis. In particular they have beneficial effects on inflammation, plaque stabilization, endothelial dysfunction, and thrombosis. Statins have also been shown to be beneficial in acute vascular events. Angiotensin-converting enzyme inhibitors have been shown to reduce cardiovascular morbidity and mortality in patients with peripheral arterial disease regardless of the presence or absence of hypertension. A number of the pleiotropic effects of statins are shared by ACE inhibitors. In summary, patients with known vascular disease should be treated aggressively with a combination of a HMG CoA reductase inhibitor, an angiotensin-converting enzyme inhibitor, an antiplatelet agent and a beta blocker if there is a history of coronary disease. They should also receive tight control of their blood pressure and blood sugar. Smokers should be encouraged to stop smoking and should be provided with pharmaceutical and emotional support by their physicians. All of these patients should have their body mass index as close to normal as possible and be on a therapeutic lifestyle diet. Regular aerobic exercise is also indicated. Patients with symptomatic claudication should be considered for cilostazol. Patients with multiple risk factors for vascular disease, but who do not have documented disease should also be on statin therapy. As more studies define the linear relationship between lower LDL-C levels and lowered risk of vascular events, indicating that the lower the LDL-C level, the lower the risk, experts are advocating more aggressive lipid-lowering therapy. In patients with peripheral arterial disease, some experts now advocate lowering the goal of LDL therapy to 70 mg/dL.

Novel therapies targeting vascular endothelium

Endothelial dysfunction has been identified as a major mechanism involved in all the stages of atherogenesis. Evaluation of endothelial function seems to have a predictive role in humans, and therapeutic interventions improving nitric oxide bioavailability in the vasculature may improve the long-term outcome in healthy individuals, high-risk subjects, or patients with advanced atherosclerosis. Several therapeutic strategies are now available, targeting both the synthesis and oxidative inactivation of nitric oxide (NO) in human vasculature. Statins seem to be currently the most powerful category of these agents, improving endothelial function and decreasing cardiovascular risk after long-term administration. Other cardiovascular agents improving endothelial function in humans are angiotensin-converting enzyme inhibitors/angiotensin receptors blockers, which increase NO bioavailability by modifying the rennin-angiotensin-aldosterone system. Newer therapeutic approaches targeting endothelial dysfunction in specific disease states include insulin sensitizers, L-arginine (the substrate for endothelial NO synthase [eNOS]) as well as substances that target eNOS "coupling," such as folates or tetrahydrobiopterin. Although there are a variety of strategies to improve NO bioavailability in human endothelium, it is still unclear whether they have any direct benefit at a clinical level.

Atorvastatin and quinapril inhibit blood coagulation in patients with coronary artery disease following 28 days of therapy

BACKGROUND

We evaluated the antithrombotic effects of statins and angiotensin-converting enzyme inhibitor (ACEI) drugs in patients with coronary artery disease (CAD).

METHODS AND RESULTS

Blood coagulation at the site of microvascular injury was assessed in 26 males with CAD before and after treatment with quinapril (10 mg day-1; n=13) or atorvastatin (40 mg day-1; n=13) for 4 weeks and an additional 4 weeks of combined therapy (quinapril+atorvastatin). Rates of prothrombin and factor V activation (FVa), fibrinogen (Fbg) cleavage and FVa inactivation showed that both quinapril and atorvastatin decreased the rates of: formation of thrombin B-chain (by 30.6%, P=0.007; and by 34.3%, P=0.003), formation of thrombin-antithrombin complexes (by 30.4%, P=0.0002; and by 40%, P=0.001), FV activation (by 19.1%, P=0.03; and by 21.8%, P=0.005) and Fbg depletion (by 29.2%, P=0.004; and by 32.7%, P=0.001). Atorvastatin alone accelerated FVa inactivation (P=0.005). A further 4 weeks of combined therapy enhanced most anticoagulant effects only when atorvastatin was added to quinapril.

CONCLUSIONS

In CAD patients, atorvastatin and quinapril slowed blood clotting at the site of microvascular injury after 28 days of therapy. Addition of atorvastatin to quinapril, but not quinapril to the statin, enhanced the anticoagulant effects. Our findings might help explain the reduced risk of myocardial infarction or stroke in patients treated with statins and/or ACEIs and the lack of clinical benefits from ACEI added to prior statin therapy in patients at cardiovascular risk.

Drug treatment of peripheral arterial disease in the elderly

Peripheral arterial disease (PAD) may be asymptomatic, may be associated with intermittent claudication or may be associated with critical limb ischaemia. Coronary artery disease (CAD) and other atherosclerotic vascular disorders may coexist with PAD. Persons with PAD are at increased risk for all-cause mortality, cardiovascular mortality and mortality from CAD. Smoking should be stopped and hypertension, diabetes mellitus, dyslipidaemia and hypothyroidism treated. HMG-CoA reductase inhibitors (statins) reduce the incidence of intermittent claudication and improve exercise duration until the onset of intermittent claudication in persons with PAD and hypercholesterolaemia. Antiplatelet drugs such as aspirin or clopidogrel (especially the latter), ACE inhibitors and statins should be given to all persons with PAD. beta-Adrenoceptor antagonists should be given if CAD is present. The phosphodiesterase type 3 inhibitor cilostazol improves exercise time until intermittent claudication. Chelation therapy should be avoided. Correct implementation of medical therapy significantly reduces the excess mortality associated with PAD. In addition, medical therapy may result in significant improvements in walking ability that may obviate the need for lower extremity angioplasty with stenting and bypass surgery.

Statins, fenofibrate, and quinapril increase clot permeability and enhance fibrinolysis in patients with coronary artery disease

BACKGROUND

Aspirin increases fibrin clot porosity and susceptibility to lysis. It is unknown whether other drugs, in combination with aspirin, used in the treatment of coronary artery disease (CAD) might affect clot structure and resistance to lysis.

AIM

The aim of the study was to assess the effects of statins, fibrates, or angiotensin-converting enzyme inhibitors (ACEIs) on fibrin clot properties.

PATIENTS AND METHODS

In a randomized double-blind study, men with advanced CAD taking low-dose aspirin were assigned to receive one of the four drugs: simvastatin 40 mg day(-1) (n = 13), atorvastatin 40 mg day(-1) (n = 12), fenofibrate 160 mg day(-1) (n = 12), and quinapril 10 mg day(-1) (n = 11) for 28 +/- 2 days. Moreover, CAD patients (n = 13) taking aspirin (75 mg day(-1)) for 8 weeks were studied after additional 4 weeks on an open-label basis. Thirty men served as healthy controls. Plasma clot permeability and tissue plasminogen activator-induced fibrinolysis were evaluated at baseline and after drug administration.

RESULTS

Permeability increased following the administration of simvastatin (by 20%; P = 0.01), atorvastatin (by 22%; P = 0.001), fenofibrate (by 16%; P = 0.02), and quinapril (by 13%; P = 0.04) like for aspirin (P < 0.001). Turbidity analysis showed that administration of any of the drugs was associated with higher maximum absorbancy, suggesting thicker fibers, and shorter fibrinolysis time (P < 0.001). Post-treatment reduction in lysis time correlated with an increase in clot porosity in all the groups (r from 0.42 to 0.61; P from 0.01 to 0.001).

CONCLUSIONS

Statins, fibrates, and ACEIs may increase plasma clot permeability and susceptibility to fibrinolysis in CAD patients receiving aspirin. This novel antithrombotic mechanism might contribute to clinical benefits of the drugs tested.

Tactics for Vascular Protection After Acute Ischemic Stroke

BACKGROUND

The vascular events that happen during ischemic stroke worsen outcomes in patients by causing edema, hemorrhagic transformation, and general neurologic tissue compromise. In the past 2 decades, clinical trials in patients after ischemic stroke focused on neuroprotection, but these strategies have failed in providing actual benefit. Vascular protection represents a new field to be explored in acute ischemic stroke in order to develop new approaches to therapeutic intervention.

PURPOSE

We identified tactics likely to provide vascular protection in patients with ischemic stroke. These tactics are based on knowledge of the molecular processes involved.

SUMMARY OF REVIEW

The pathologic processes due to vascular injury after an occlusion of a cerebral artery can be separated into acute (those occurring within hrs), subacute (hrs to days), and chronic (days to mo). Targets for intervention can be identified for all three stages. In the acute phase, superoxide is the predominant mediator, followed by inflammatory mediators and proteases in the subacute phase. In the chronic phase, proapoptotic gene products have been implicated. Many already-marketed therapeutic agents (statins, angiotensin modulators, erythropoietin, minocycline, and thiazolidinediones), with proven safety in patients, have been shown to have activity against some of the key targets of vascular protection.

CONCLUSION

Currently available pharmacologic agents are poised for clinical trials of vascular protection after acute ischemic stroke.

Effect of simvastatin given alone and in combination with valsartan or enalapril on blood pressure and the structure of mesenteric resistance arteries and the basilar artery in the genetically hypertensive rat model

1. The aims of the present study were to investigate, in the New Zealand genetically hypertensive (GH) rat model, the effects of treatment with simvastatin, alone or in combination with valsartan or enalapril, on blood pressure (BP) and structural remodelling of mesenteric resistance arteries (MRA) and of the basilar artery, an artery that plays a major role in the regulation of cerebral resistance. 2. Genetically hypertensive rats were treated with simvastatin at two dose levels (5 and 10 mg/kg per day) and simvastatin in combination with valsartan or enalapril (also 5 and 10 mg/kg per day) from the age of 7 to 12 weeks. Systolic BP and bodyweight were measured weekly. 3. At the end of the experiment, following fixation by perfusion, MRA and the basilar artery were excised and embedded in Technovit (a glycol methacrylate medium; Heraeus Kulzer, Werheim, Germany). Serial sections were cut and stereological techniques used to determine tunica media width and cross-sectional area (CSA), lumen diameter and the ratio of media width/lumen diameter. 4. Simvastatin monotherapy did not lower BP at either dose. In the high- and low-dose groups, the combination of simvastatin + enalapril lowered BP more than with enalapril alone; this was also true for the simvastatin + valsartan combination in the lower-dose group. 5. The MRA were hypotrophically remodelled by the 10 mg/kg per day dose of simvastatin; the 5 mg/kg per day dose caused hypotrophic remodelling with decreased media/lumen ratio. Valsartan and enalapril caused hypotrophic remodelling together with outward remodelling of the lumen in the 10 mg/kg per day valsartan group and, in all groups, a reduction in the media/lumen ratio, with the greatest effect observed in the high-dose groups. 6. The combination treatments of simvastatin + valsartan and simvastatin + enalapril did not have any consistent extra effect on MRA remodelling. 7. In the basilar artery, high-dose simvastatin had a hypotrophic effect on the media and both doses reduced the media/lumen ratio independently of any change in BP. 8. Simvastatin given in combination with valsartan produced a slight further reduction in medial CSA, media width and ratio. In combination with enalapril, there was little consistent additional effect. 9. Simvastatin monotherapy hypotrophically remodelled the media of the basilar artery in the GH rat model, even in the absence of changes in BP. A similar structural effect may explain, in part, the reduction in stroke seen in patients treated with statins.

Manipulation of the Renin Angiotensin System in Peripheral Arterial Disease

The Heart Outcomes Prevention Evaluation (HOPE) study has provided evidence for the use of ramipril for secondary cardiac prevention for patients with peripheral arterial disease. Despite this many vascular surgeons and general practitioners are reluctant to prescribe ACE inhibitors in a group of patients perceived to have a high incidence of renal artery stenosis. This review aims to review the pathophysiology of the renin-angiotensin system and make evidence based recommendations for commencing ACE inhibitors as part of a comprehensive delivery of best medical therapy to patients with peripheral arterial disease.

Nitric oxide, angiotensin II, and hypertension

Although initially adaptive, the changes that accompany hypertension, namely, cell growth, endothelial dysfunction, and extracellular matrix deposition, eventually can become maladaptive and lead to end-organ disease such as heart failure, coronary artery disease, and renal failure. A functional imbalance between angiotensin II (Ang II) and nitric oxide (NO) plays an important pathogenetic role in hypertensive end-organ injury. NO, an endogenous vasodilator, inhibitor of vascular smooth muscle and mesangial cell growth, and natriuretic agent, is synthesized in the endothelium by a constitutive NO synthase. NO antagonizes the effects of Ang II on vascular tone, cell growth, and renal sodium excretion, and also down-regulates the synthesis of angiotensin-converting enzyme (ACE) and Ang II type 1 receptors. On the other hand, Ang II decreases NO bioavailability by promoting oxidative stress. A better understanding of the pathophysiologic mechanisms involved in hypertensive end-organ damage may aid in identifying markers of cardiovascular susceptibility to injury and in developing therapeutic interventions. We propose that those antihypertensive agents that lower blood pressure and concomitantly restore the homeostatic balance of vasoactive agents such as Ang II and NO within the vessel wall would be more effective in preventing or arresting end-organ disease.

Modulatory effects of HMG-CoA reductase inhibitors in diabetic microangiopathy

3-hydroxy-3-methyl-glutaryl CoA (HMG-CoA) reductase inhibitors or statins are competitive inhibitors of the rate-limiting enzyme in cholesterol biosynthesis. Several large landmark clinical studies have shown a marked reduction of cardiovascular mortality and morbidity in patients treated with statins. Because of the strong association between serum cholesterol levels and coronary artery disease, investigators initially assumed that the predominant beneficial effects of statins result from their lipid-lowering properties. However, more recent observations have suggested that the clinical benefits of statins may be in part independent of their cholesterol-lowering effects. The pleiotropic or cholesterol-independent effects of statins might result from preventing the production of isoprenoids. Isoprenoids serve as important lipid attachments for the post-translational modification of a variety of proteins such as small GTP binding proteins implicated in intracellular signaling. The list of different pleiotropic effects of statins is still growing and, among others, includes the modulatory effects of statins on endothelial function, oxidative stress, coagulation, plaque stability, and inflammation. The pleiotropic effects of statins represent an area of great interest in prevention and therapy of cardiovascular and other chronic diseases. An area of particular interest is the potential beneficial effects of statins in diabetes and its micro/macrovascular complications. This review summarizes our current understanding of the pleiotropic effects of statins in diabetes and the modulatory effects of statins in various pathobiological pathways involved in diabetes and its complications.