The reno-protective role of AT(1)-receptor blockers

The crosstalk among TLR2, TLR4 and pathogenic pathways; a treasure trove for treatment of diabetic neuropathy

Diabetes is correlated with organ failures as a consequence of microvascular diabetic complications, including neuropathy, nephropathy, and retinopathy. These difficulties come with serious clinical manifestations and high medical costs. Diabetic neuropathy (DN) is one of the most prevalent diabetes complications, affecting at least 50% of diabetic patients with long disease duration. DN has serious effects on patients' life since it interferes with their daily physical activities and causes psychological comorbidities. There are some potential risk factors for the development of neuropathic injuries. It has been shown that inflammatory mechanisms play a pivotal role in the progression of DN. Among inflammatory players, TLR2 and TLR4 have gained immense importance because of their ability in recognizing distinct molecular patterns of invading pathogens and also damage-associated molecular patterns (DAMPs) providing inflammatory context for the progression of a wide array of disorders. We, therefore, sought to explore the possible role of TLR2 and TLR4 in DN pathogenesis and if whether manipulating TLRs is likely to be successful in fighting off DN.

Diabetic kidney disease; review of the current knowledge

Diabetes is the most common cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD) in most parts of the world. 20 to 30% of diabetic patient have diabetic nephropathy in type 1 and type 2. Hyperglycemia is the key of nephropathy creation. Hyperglycemia also by production of toxic materials, advanced glycosylated end product (AGE), increased activity of aldose reductase has some role. Some metabolites of arachidonic acid, hemodynamic derangements and genetic factors have also some role. Although diabetic nephropathy is most common cause of nephropathy in these patients, but diabetic patients are also prone to other urinary tract and renal parenchymal disease and should not be confused with renal failure due to diabetic nephropathy. The principle of treatment of diabetic nephropathy is based on tight control of hyperglycemia, tight control of blood pressure and glomerular pressure, control of dyslipidemia, restriction of protein intake and smoking withdrawal.

Hypertension and angiogenesis in the aging kidney: a review

With advanced aging, main components of the kidney are altered, including blood vessels, glomeruli and tubulointerstitium. Disruption in these 3 elements is interconnected and associated with several modifications, such as loss of kidney mass and systemic, metabolic and immunologic diseases. In this review we focus on renal blood vessels, the key role of hypertension and angiogenesis in the elderly kidney, the hemodynamic and molecular mechanisms underlying this aging process and the main factors involved. So far, the present data suggests a strong association between renal disease and hypertension and the impairment of regulatory mechanisms, such as angiogenesis in the aging kidney. The endothelium is a key player in vascular control and appears to be also disrupted in many compensatory functions (i.e., vasodilation). Perspectives for the management of the dysfunctional aging kidney are also addressed.

Angiotensin Receptor Blockade in Acute Stroke. the Scandinavian Candesartan Acute Stroke Trial: Rationale, Methods and Design of a Multicentre, Randomised- and Placebo-Controlled Clinical Trial (NCT00120003)

Background

Elevated blood pressure following acute stroke is common, and yet early antihypertensive treatment is controversial. ACCESS suggested a beneficial effect of the angiotensin receptor blocker candesartan in the acute phase of stroke, but these findings need to be confirmed in new, large trials.

Aims and design

The Scandinavian Candesartan Acute Stroke Trial is an international randomised, placebo-controlled, double-blind trial of candesartan in acute stroke. We plan to recruit 2500 patients presenting within 30 h of stroke (ischaemic or haemorrhagic) and with systolic blood pressure ≥ 140 mmHg. The recruited patients are randomly assigned to candesartan or placebo for 7-days (doses increasing from 4 to 16mg once daily). Randomisation is performed centrally via a secure web interface. The follow-up period is 6-months. Patients are included from the following nine North-European countries: Norway, Sweden, Denmark, Belgium, Germany, Poland, Lithuania, Estonia and Finland.

Study outcomes

There are two co-primary effect variables:

Funding

The Scandinavian Candesartan Acute Stroke Trial receives basic funding from Norwegian health authorities. AstraZeneca supplies the trial drugs, and AstraZeneca and Takeda support the trial with limited, unrestricted grants.

Summary

The Scandinavian Candesartan Acute Stroke Trial is the first large trial of angiotensin receptor blockers in patients with elevated blood pressure and acute stroke, and aims to answer whether treatment with angiotensin receptor blockers is beneficial for this indication.

Telmisartan shows an equivalent effect of vitamin C in further improving endothelial dysfunction after glycemia normalization in type 1 diabetes

OBJECTIVE

Long-lasting hyperglycemia in type 1 diabetic patients induces permanent alterations of endothelial function by increased oxidative stress, even when glycemia is normalized.

RESEARCH DESIGN AND METHODS

In this study, 36 type 1 diabetic patients and 12 control subjects were enrolled. The diabetic patients were divided into three groups. The first group was treated for 24 h with insulin, achieving a near normalization of glycemia. After 12 h of this treatment, vitamin C was added for the remaining 12 h. The second group was treated for 24 h with vitamin C. After 12 h of this treatment, insulin was started, achieving a near normalization of glycemia for the remaining 12 h. The third group was treated for 24 h with both vitamin C and insulin, achieving near normalization of glycemia. The same protocols were performed after 1 month of telmisartan or placebo.

RESULTS

Neither normalization of glycemia nor vitamin C treatment alone was able to normalize endothelial dysfunction or oxidative stress. Combining insulin and vitamin C normalized endothelial dysfunction and decreased oxidative stress to normal levels. Telmisartan significantly improved basal endothelial function and decreased nitrotyrosine plasma levels. In patients treated with telmisartan, a near normalization of both flow-mediated vasodilation and oxidative stress was achieved when glycemia was normalized, whereas adding vitamin C infusion did not show further effect on endothelial function or nitrotyrosine plasma levels.

CONCLUSIONS

These data indicate that combining the normalization of glycemia with an antioxidant can normalize endothelial function in type 1 diabetic patients and that telmisartan works as an antioxidant like vitamin C.

High Blood Pressure in Acute Ischemic Stroke and Underlying Disorders

BACKGROUND

The Acute Candesartan Cilexetil Therapy in Stroke Survivors (ACCESS) study indicated that early treatment with an angiotensin type 1 receptor blocker in acute stroke patients who had relatively high blood pressure improved cardiovascular morbidity and mortality in the chronic stage. To better interpret the findings of this study, we determined whether stroke patients with high acute blood pressure had specific underlying conditions.

METHODS

We divided 712 consecutive patients who were hospitalized within 48 h after the onset of brain infarction into two groups: 77 patients with high acute blood pressure that met the criteria of the ACCESS study and the 635 remaining patients. Underlying risk factors and comorbidities, stroke characteristics, as well as mortality, vascular events, and disability at 3 weeks were compared between the two groups.

RESULTS

Patients with high acute blood pressure more frequently had diabetes mellitus (p < 0.01), intracranial arterial stenosis (p < 0.02), higher levels of hemoglobin A1c (p < 0.005), higher creatinine levels (p < 0.005), and tended to more frequently have ischemic heart disease (p < 0.09) and infarcts <1.5 cm in diameter (p < 0.09) than the other patients. On multivariate analysis, high levels of hemoglobin A1c, high creatinine levels, and intracranial arterial stenosis were independently predictive of high acute blood pressure. At 3 weeks after the stroke onset, patients with high acute blood pressure were more dependent in their daily living activities (p < 0.02) and more frequently developed vascular events or death (p < 0.005) than the other patients.

CONCLUSIONS

Poorly controlled diabetes mellitus and advanced renal damage appeared to correlate with acute hypertension after stroke. Since intracranial arterial stenosis also seemed to contribute to high acute blood pressure, one should be careful not to induce cerebral hypoperfusion by the early use of antihypertensives.

The importance of early antihypertensive efficacy: the role of angiotensin II receptor blocker therapy

Desirable features of antihypertensive agents include efficacy, tolerability, prolonged duration of action and rapid achievement of target blood pressure (BP). Recent studies have examined the relationship between the onset of antihypertensive effect and cardiovascular events. Data from the Valsartan Antihypertensive Long-term Use Evaluation (VALUE), the Study on Cognition and Prognosis in the Elderly (SCOPE), and the Systolic Hypertension in Europe (Syst-Eur) trials support the hypothesis that the time it takes to reach target BP influences cardiovascular outcomes. VALUE, which compared BP-lowering and clinical event rates between patients treated with the angiotensin II receptor blocker (ARB) valsartan or the calcium channel blocker (CCB) amlodipine as well as between those who achieved immediate or delayed BP control, provides the strongest evidence of this to date. Additional data from SCOPE and Syst-Eur suggest that delays of 3 months to 2 years in starting antihypertensive therapy can increase the risk of certain cardiovascular end points, especially stroke. These data suggest that it may be beneficial to examine the efficacy of antihypertensive agents, not only long term, but also at earlier times to assess the onset and impact of early antihypertensive effect. The ARB olmesartan medoxomil (olmesartan) and the CCB amlodipine were compared in a randomized, double-blind, placebo-controlled clinical trial, which demonstrated that the onset of antihypertensive effect of olmesartan is comparable with that of amlodipine. Another study demonstrated that more patients treated with olmesartan achieved target BPs within 2 weeks of treatment compared with the ARBs losartan, valsartan and irbesartan.

Cerebrovascular protection and antihypertensive therapy

PURPOSE OF REVIEW

Our aim is to review the association between blood pressure and stroke and analyse data from randomized controlled trials involving diverse therapies, especially those regarding the renin-angiotensin system. In addition, an overview of stroke pathogenesis is given and its relationship with treatment action mechanisms reviewed.

RECENT FINDINGS

Stroke is a leading cause of death worldwide. In addition, many survivors of stroke suffer different degrees of disability. Because of the ageing of the global population, especially in regions of rapid economic growth, stroke will remain the second leading cause of death and in terms of disability it will be among the five most important causes in both developing and developed countries. High blood pressure is the most important risk factor for stroke, either ischemic or haemorrhagic, and established hypertension is the most prevalent modifiable risk factor. Data from controlled trials of blood-pressure-lowering treatment have demonstrated that treatment considerably lowers the risk of stroke within a few years of starting treatment. However, there exists controversy about the most efficient treatment regimen for primary and secondary prevention of stroke among the different blood-pressure-lowering treatments.

SUMMARY

Debate rages as to whether the benefits of treating high blood pressure are simply determined by the quality of blood-pressure control, or whether the choice of drug therapy adds or detracts from the expected benefits of blood-pressure reduction. The desirable future interventional comparative studies should consent to determine specific effects of drug classes on cardiovascular risk in the absence of the confounding effect of a relevant blood-pressure reduction that may counteract the potential blood-pressure-independent benefits of specific drug classes.

Effects of dual blockade of the renin-angiotensin system in primary proteinuric nephropathies

BACKGROUND

Blockade of the renin-angiotensin system (RAS) with angiotensin converting enzyme (ACE) inhibitors or with angiotensin II type 1 (AT1) receptor blockers has been shown to reduce proteinuria and to slow down the progression of renal disease in diabetic and non-diabetic primary proteinuric nephropathies. Additionally, this beneficial effect is not dependent on blood pressure control.

METHODS

To assess and compare the effects of lisinopril (up to 40 mg/day), candesartan (up to 32 mg/day) and combination therapy (lisinopril up to 20 mg/day plus candesartan up to 16 mg/day) on urinary protein excretion, 45 patients with primary proteinuric nephropathies (urinary protein/creatinine ratio 3.8+/-2.4 g/g) and normal or slightly reduced renal function (CCr 95+/-33 mL/min) were enrolled in a six month multicenter, prospective, open, randomized, active-controlled and parallel-group trial with 1:1:1 allocation. Blood pressure goal was set at or below 125/75 mm Hg for all patients, with additional antihypertensive medication prescribed if required.

RESULTS

Renal function, estimated by creatinine clearance, remained stable throughout the study. Hyperkalemia (K>5.5 mmol/L) was detected in 3.1% of all measurements in follow-up, and was more frequent in patients treated with lisinopril alone or lisinopril plus candesartan (P<0.001) than in those on candesartan alone. No other relevant adverse event was recorded. The blood pressure goal (<125/75 mm Hg) was achieved by week 4 in all treatment groups (P<0.005 when compared to baseline), and afterwards the mean systolic and diastolic blood pressure remained below these values until the end of the trial with no statistically significant differences between groups. Urinary protein/creatinine ratio (percentage reduction 95% confidence intervals CI) decreased in patients treated with lisinopril alone to -33% (CI -12-56) to -31% (CI 0-68) and to -50% (CI -9-90), in patients treated with candesartan to -28% (CI -12-45), to -41% (CI -30-52) and to -48% (CI -32-63), in patients treated with the combination of both to -60% (CI -44-77) to -54% (CI -38-69) and to -70% (CI -57-83) at two, three, and six months, respectively. All comparisons with baseline achieved statistical significance and treatment with combination therapy was statistically more effective in proteinuria reduction than treatment with candesartan alone at two and six months (P=0.004 and P=0.023, respectively) and than treatment with lisinopril only at two months (P=0.03).

CONCLUSION

Dual blockade of the renin-angiotensin system with ACE inhibitors and AT1 receptor blockers produces a beneficial antiproteinuric effect that could not be explained only by the systemic blood pressure reduction. All treatments were well tolerated.