Combined Treatment With Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers: A Review of the Current Evidence

The effects of single and combined application of ramipril and losartan on renal structure and function in hypertensive rats

The objective of the present study was to investigate the effects of single and combined administration of ramipril and losartan on renal structure and function in spontaneously hypertensive rats (SHRs). Thirty-two 9-week-old SHRs and eight Wistar-Kyoto (WKY) rats were randomly divided into five groups: the WKY control group, the SHR control group, the SHR-ramipril group, the SHR-losartan group, and the SHR-combined mediation group. The rat body weight, SBP, heart rate, and urinary albumin excretion rate (UAER) were measured. (1) The SBP was reduced to the normal level in all groups of rats except for the SHR control group. Combined administration of ramipril and losartan can be reduced to the normal level earlier than single (P < 0.01). (2) The SHR-ramipril group and the SHR-losartan group still experienced a higher UAER than that in the WKY control group (P < 0.01). (3) The renal mass/BW ratio was decreased in the SHR-ramipril group, SHR-losartan group, and SHR-combined medication group compared to that in the SHR control group (P < 0.01). (4) Compared with the SHR control group, the SHR-ramipril group, the SHR-losartan group, and the SHR-combined medication group had a lower percentage of the IOD of glomerular collagen relative to the glomerular area (P < 0.01). (5) The reduction in tubulointerstitial injury score was more significant in the SHR-combined medication group than in the SHR-ramipril group and the SHR-losartan group (P < 0.01). The combination of ramipril and losartan is superior to either single drug in reducing the UAER, resisting glomerular collagen deposition, and protecting renal tubular structure.

Protective Role of Ramipril and Candesartan against Myocardial Ischemic Reperfusion Injury: A Biochemical and Transmission Electron Microscopical Study

The present study was designed to investigate the role of combined administration of Ramipril and Candesartan against in vitro myocardial ischemic reperfusion injury in rat. Male Wistar albino rats were divided into five groups (n = 6) and treated with saline (10 mL/kg), Ramipril (2 mg/kg), Candesartan (1 mg/kg), and the combination of both drugs, respectively 24 h before induction of global ischemia (5 min of stabilization, 9 min of global ischemia, and 12 min of reflow). Combination of Ramipril and Candesartan when compared to the monotherapy significantly increased the levels of superoxide dismutase, reduced glutathione, catalase, and nitric oxide and decreased the levels of thiobarbituric acid reactive substances. In addition, the superior protective role of combination of Ramipril and Candesartan on ischemia induced myocardial damage was further confirmed by well preserved myocardial tissue architecture in light microscopy and transmission electron microscopy analysis studies. The combination was proved to be effective in salvaging the myocardial tissue against ischemic reperfusion injury when compared to the monotherapy of individual drugs and further investigations on protective mechanism of drugs by increasing the nitric oxide level at molecular levels are needed.

Peripheral arterial disease: implications beyond the peripheral circulation

Peripheral arterial disease (PAD) affects a considerable percentage of the population. The manifestations of this disease are not always clinically overt. As a result, PAD remains underdiagnosed and undertreated. PAD is not just a disease of the peripheral arteries, but also an indication of generalized vascular atherosclerosis. PAD patients also have a high prevalence of other arterial diseases, such as coronary/carotid artery disease and abdominal aortic aneurysms. PAD is also a predictor of increased risk of lung and other cancers. The most often used examination for the establishment of the diagnosis of PAD, the ankle-brachial pressure index (ABPI), is also a predictor of generalized atherosclerosis, future cardiovascular events and cardiovascular mortality. Several markers that have been linked with PAD (e.g. C-reactive protein, serum bilirubin levels) may also have predictive value for other conditions besides PAD (e.g. kidney dysfunction). The management of PAD should therefore not be restricted to the peripheral circulation but should include measurements to manage and decrease the systemic atherosclerotic burden of the patient.

The uric acid metabolism pathway as a therapeutic target in hyperuricemia related to metabolic syndrome

INTRODUCTION

Uric acid (UA) increase is considered an important risk factor for the development of cardiovascular disease (CVD) favoring oxidative stress and endothelial dysfunction and is also involved in metabolic syndrome (MS) pathophysiology.

AREAS COVERED

Insulin has a physiological action on renal tubules, causing a reduction in UA clearance, what could explain the hyperuricemia found in MS. On the other hand, it was also hypothesized a causal role of UA in fructose-induced MS. Moreover, it has been suggested that higher UA levels predict the development of MS. MS subjects present a redox imbalance and UA participates in this process. UA can contribute to oxidative stress present in MS; however, it has also an important role in the antioxidant defense system. Although UA may have a protective effect due to its antioxidant properties, it is clear that the dominant effect of UA in MS is deleterious. All-cause mortality and CVD have been shown to be increased with higher UA levels.

EXPERT OPINION

It is extremely important to prescribe drugs which concomitantly decrease hyperuricemia and improve co-morbidities associated with hyperuricemia. Long-term studies to verify the consequences of decreasing UA concentration below current recommendations in asymptomatic patients are needed.

Serum uric acid levels and renal damage in hyperuricemic hypertensive patients treated with renin-angiotensin system blockers

BACKGROUND

A correlation between hyperuricemia and renal target organ damage (TOD) was shown in hypertensive patients, locally mediated by the activation of renin-angiotensin system (RAS). We investigated whether high serum uric acid (UA) levels could negatively affect tubulointerstitial damage in hyperuricemic essential hypertensive patients with normal renal function, on treatment with RAS-blocking drugs.

METHODS

We studied 40 patients with World Health Organization stage I-II essential hypertension, 9 with high serum UA levels (hyperuricemic group) and 31 with normal serum UA levels (normouricemic group, either normouricemics, n = 15, or formerly hyperuricemics in chronic allopurinol treatment, n = 16). All patients were on RAS-blocking drugs (either angiotensin-converting enzyme inhibitors or angiotensin II receptors blockers). Evaluation of renal TOD included urinary albumin excretion (UAE), Doppler ultrasound renal resistive index (RRI) and renal volume-to-resistive index ratio (RV/RRI) measurements.

RESULTS

Hyperuricemics had significantly higher RRI and lower RV/RRI values than normouricemics. Creatinine clearance and UAE were similar between groups. Linear regression analysis showed that RV/RRI values were inversely related to serum UA levels (r = -0.57, P < 0.01). The logistic regression analysis selected serum UA as an independent predictor of decreased RV/RRI (odds ratio 4.45, 95% CI 1.47-13.45, P = 0.01).

CONCLUSIONS

In hyperuricemic hypertensives normal serum UA levels are associated with normal RV/RRI, integrated marker of tubulointerstitial damage and renal arteriolopathy, independently of RAS activation.

Beyond immunosuppression – challenges in the clinical management of lupus nephritis

Lupus nephritis remains the most common severe manifestation of SLE with increased risk of death and end-stage renal disease. Although, recent research has focused on the choice of immunosuppressive in its treatment, other factors, including the quality and delivery of healthcare, the management of glucocorticoids and co-morbidity are probably of more importance. There has been significant progress in induction regimes with the successful use of mycophenolate mofetil, low dose intravenous cyclophosphamide and development of sequential regimens whereby cyclophosphamide is followed by an alternative immunosuppressive. However, the attention on the day-to-day management of lupus nephritis in the clinic has merited less attention. In this article, we aim to address more widely the major issues which are encountered regularly in the long-term management of these patients. The overall goals are the reduction of mortality and preservation of renal function.

Chronic kidney disease at high altitude

With a prevalence of 10 to 11% in the general population, it is likely that many patients with chronic kidney disease will visit or reside in mountainous areas. Little is known, however, about whether short- or long-duration, high-altitude exposure poses a risk in this patient population. Given that many areas of the kidney are marginally oxygenated even at sea level and that kidney disease may result in further renal hypoxia and hypoxia-associated renal injury, there is concern that high altitude may accelerate the progression of chronic kidney disease. In this review, we address how chronic kidney disease and its management is affected at high altitude. We postulate that arterial hypoxemia at high altitude poses a risk of faster disease progression in those with preexisting kidney disease. In addition, we consider the risks of developing acute altitude illness in patients with chronic kidney disease and the appropriate use of medications for the prevention and treatment of these problems.

The need for wider and appropriate utilization of aspirin and statins in the treatment and prevention of cardiovascular disease

There is an increasing burden of occlusive cardiovascular disease (CVD) in developed, as well as in developing, countries. In fact, the WHO has projected that CVD will become the leading cause of death in the world in the next 10 years. The proximate cause of virtually all occlusive vascular events is thrombosis and the principal underlying cause is atherosclerosis. Aspirin, which inhibits platelet-dependent cyclooxygenase for the entire life of the platelet, has clinically important antithrombotic effects. Statins, which principally decrease low-density lipoprotein cholesterol, triglycerides and increase high-density lipoprotein cholesterol, have clinically important antiatherogenic effects. In secondary prevention, in a wide range of patients who have survived a prior myocardial infarction (MI), occlusive stroke, transient ischemic attack, as well as other high-risk conditions, long-term use of aspirin confers statistically significant and clinically important reductions in MI, stroke and CVD death. In addition, aspirin confers similar benefits when administered during acute MI or acute occlusive stroke. In primary prevention, aspirin confers a statistically significant and clinically important reduction in risk of a first MI but the data on stroke and CVD death remain inconclusive, so aspirin should be prescribed on an individual basis by the healthcare provider who weighs this clear benefit against long-term side effects. In a meta-analysis of 14 randomized trials of 90,056 subjects treated for 5 years, statins confer statistically significant and clinically important reductions in MI, stroke, CVD death and total mortality. In a meta-analysis of randomized trials of statins, in which aspirin was used in varying frequencies, the combination of aspirin and statins conferred greater clinical benefits than either agent alone on MI, occlusive stroke and CVD death. At present, the wider and more appropriate use of aspirin and statins will reduce premature MI, stroke and CVD death.

Management and treatment of chronic kidney disease

Estimates suggest that 30 million Americans have some degree of chronic kidney disease. By 2030, more than 2.2 million people will require treatment for end-stage renal disease, causing a significant impact on healthcare costs in the United States.

Should a statin be prescribed to every patient with heart failure?

Chronic heart failure (HF) represents an emerging epidemic since its prevalence is continuously increasing despite advances in treatment. Many recent clinical studies have clearly demonstrated that statin therapy is associated with improved outcomes in HF irrespective of aetiology (ischaemic or not) or baseline cholesterol levels. Indeed, most of the conducted large statin trials and trials in HF have demonstrated a positive effect of statins in HF patients. Furthermore, the use of statins in HF seems to be safe as none of the recent trials has resulted in worse outcomes for HF patients treated with statins. Potential mechanisms through which statins could benefit the failing myocardium include non-sterol effects of statins, as well as effects on nitric oxide and endothelial function, inflammation and adhesion molecules, apoptosis and myocardial remodelling and neurohormonal activation. This review discusses the pathophysiological basis of statin effects on HF and focuses on clinical data for the benefit from statin use in this setting. Until today there are no official recommendations in both the American and the European guidelines regarding the use of statins in HF patients, as the available data come from small observational or larger but retrospective, non-randomised studies. Therefore, HF patients should be treated according to current lipid guidelines. Large randomised clinical trials are underway and will further delineate the role of statin therapy in HF patients. Until more data are available, we could not recommend statin use to every patient with HF irrespective of HF aetiology and baseline cholesterol levels.

Drug therapy for the secondary prevention of stroke in hypertensive patients: current issues and options

Hypertension is the major risk factor for ischaemic and haemorrhagic clinical strokes as well as for silent brain infarcts with a continuous association between both systolic and diastolic blood pressures. Epidemiological data highlight the increasing burden to come over the next decades. Without any doubt, antihypertensive treatment is the most important therapy to reduce the risk of stroke by approximately 30-40%. International guidelines recommend antihypertensive treatment for primary prevention with evidence level A. Recurrent strokes or transient ischaemic attack (TIA) are an important practical, clinical and economic problem, and have a major impact on the development of vascular dementia. All stroke patients and patients with TIA have to be regarded as very high-risk patients. Hypertension increases the risk of recurrent strokes. Only limited data directly address the role of blood pressure treatment among individuals with stroke or TIA. There is a general lack of definitive data regarding when to start antihypertensive treatment in the initial phase, and treatment of hypertension in the acute period after stroke is still under debate. Experimental and clinical data suggest that reducing the activity of the renin-angiotensin aldosterone system (RAAS) may have beneficial effects beyond the lowering of blood pressure. There is increasing evidence of cerebroprotective effects for medication influencing the RAAS, such as angiotensin receptor antagonists or ACE inhibitors. The MOSES study showed for the first time superiority of an angiotensin receptor antagonist compared with a calcium channel antagonist in antihypertensive treatment for secondary stroke prevention. Optimal blood pressure range in secondary prevention seems to be 120-140/80-90 mm Hg, but questions about a J- or U-shaped curve are still not answered sufficiently. The effects of additional antihypertensive treatment in the evening for stroke patients with 'non-dipping' blood pressure need to be investigated.Currently, the most important goal in primary and secondary prevention of stroke is a strict normotensive blood pressure control. Antihypertensive treatment is recommended for both prevention of recurrent stroke and prevention of other vascular events in individuals who have had an ischaemic stroke or TIA (class I, level of evidence A). Many open questions remain and funding of stroke research needs to be increased in the near future.

Hypertension and kidney protection in the elderly: what is the evidence in 2007?

Hypertension and diabetes mellitus are the two most widely recognized risk factors for cardiovascular disease (CVD), chronic kidney disease (CKD), and end-stage renal disease (ESRD) requiring dialysis/transplantation; both become increasingly important as one ages. Common pathways and mechanisms are involved in the development of renal vascular lesions in both conditions, and effective treatments for each are now available to reduce morbidity, mortality and progression of organ damage. Although this review will focus primarily on the ability to protect the kidney and vasculature elsewhere by lowering blood pressure in the elderly, other approaches, specifically dietary restriction of protein, strict control of diabetes mellitus, and the management of the different dyslipidemias, must be used in conjunction with the antihypertensive agents to obtain optimum protection.

The role of renin–angiotensin system inhibition in the treatment of hypertension in metabolic syndrome: are all the angiotensin receptor blockers equal?

The metabolic syndrome (MetS) is a strong predictor of cardiovascular morbidity and mortality, as well as new Type 2 diabetes. MetS consists of visceral obesity, elevated blood pressure, impaired glucose metabolism, atherogenic dyslipidaemia (elevated triglycerides and low levels of high-density lipoprotein cholesterol), as well as other metabolic abnormalities. The underlying pathophysiology seems to be largely, but not uniquely, attributable to insulin resistance. Existing antihypertensive drugs were designed to lower blood pressure rather than to modify the metabolic abnormalities associated with hypertension. This review considers the role of renin-angiotensin system inhibition and especially the use of angiotensin receptor blockers (ARBs) in the treatment of hypertension in MetS. There are differences among ARBs. Among them is the uricosuric effect of losartan. Furthermore, telmisartan may function as a partial agonist of the peroxisome proliferator-activated receptor-gamma (PPAR-gamma).

Elevated serum uric acid levels in metabolic syndrome: an active component or an innocent bystander?

Elevated serum uric acid (SUA) levels are commonly seen in patients with the metabolic syndrome (MetS). Several mechanisms, both direct and indirect, connect the increased SUA levels with the established diagnostic criteria of MetS. It is possible that the increased cardiovascular disease risk associated with the MetS is partially attributed to elevated circulating SUA concentration. Several drugs used in the treatment of MetS may alter SUA levels. Thus, lifestyle measures together with the judicious selection of drugs for the treatment of hypertension, dyslipidemia, and insulin resistance associated with MetS may result in a reduction of SUA levels and possibly cardiovascular disease risk. This review summarizes the pathophysiologic association between SUA and MetS and focuses on the prevention of hyperuricemia and its cardiovascular consequences.

Statins: another class of antihypertensive agents?

The assessment of global cardiovascular risk is an essential step in the management of atherosclerotic disease prevention. Among the risk factors to be addressed are hypertension and hyperlipidaemia; these commonly coexist. A neutral or lipid-friendly antihypertensive agent is probably useful in the presence of lipid abnormalities. Similarly, statins have been shown to decrease cardiovascular risk in hypertensive patients. There is also experimental and clinical evidence that statins have blood pressure (BP)-lowering effects. In this review, we discuss the beneficial effects of statins on BP, and provide an overview of the underlying pathophysiology. We also consider the evidence justifying the use of statins in the management of hypertensive patients.