The role of α-blockers in the management of prostate cancer

Prostate cancer is the second most common cause of cancer death in men in the US. Patients with prostate cancer are initially treated with surgical resection, radiation or antiandrogen therapy. After an initial remission, however, the majority of prostate tumours evolve into a highly aggressive, metastatic androgen-independent state, for which successful therapy has not yet been established. During the past few years, new perspectives have emerged towards the development of preventive and therapeutic approaches for prostate cancer. Quinazoline-based α₁-blockers have been shown to have antitumour efficacy against prostate cancer cells in inducing apoptosis and anoikis via an α₁-adrenoceptor-independent mechanism. Specifically, doxazosin and terazosin can induce apoptosis, inhibit invasion and migration of prostate cancer and endothelial cells, and reduce their adhesion potential to extracellular matrix components, thus enhancing their susceptibility to anoikis. This review discusses recent evidence suggesting the apoptotic efficacy of quinazoline-based α₁-adrenoceptor antagonists, doxazosin and terazosin and speculates on the therapeutic promise of these drugs as novel antitumour agents against prostate cancer. From a drug discovery perspective, separation of the effect of doxazosin on apoptosis in prostate cancer cells from its original pharmacological activity in normal prostate cells, will provide a molecular basis in developing a novel class of apoptosis-inducing agents through lead optimisation.     

Targeting PPARβ/δ for the treatment of type 2 diabetes mellitus

INTRODUCTION: The nuclear receptors Peroxisome Proliferator-Activated Receptors (PPAR)α and PPARγ are therapeutic targets for hypertriglyceridemia and insulin resistance, respectively. Evidence is now emerging that the PPARβ/δ isotype is a potential pharmacological target for the treatment of insulin resistance and type 2 diabetes mellitus. AREAS COVERED: In this review, the capacity of PPARβ/δ to prevent the development of insulin resistance and type 2 diabetes mellitus is discussed. Special emphasis is placed on preclinical studies and the molecular mechanisms responsible for its actions in the main cell types involved in these pathologies: adipocytes, β-cells, skeletal muscle cells and hepatocytes. EXPERT OPINION: While several concerns remain for the development of PPARβ/δ agonists, these drugs have demonstrated their efficacy in the treatment of insulin resistance and type 2 diabetes mellitus in preclinical studies, as well as in a few short clinical studies in humans. Although this data is promising, additional studies must be performed to confirm the efficacy and safety of these drugs in the treatment of type 2 diabetes mellitus.     

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).     

High-carbohydrate high-fat diet–induced metabolic syndrome and cardiovascular remodeling in rats

The prevalence of metabolic syndrome including central obesity, insulin resistance, impaired glucose tolerance, hypertension, and dyslipidemia is increasing. Development of adequate therapy for metabolic syndrome requires an animal model that mimics the human disease state. Therefore, we have characterized the metabolic, cardiovascular, hepatic, renal, and pancreatic changes in male Wistar rats (8-9 weeks old) fed on a high-carbohydrate, high-fat diet including condensed milk (39.5%), beef tallow (20%), and fructose (17.5%) together with 25% fructose in drinking water; control rats were fed a cornstarch diet. During 16 weeks on this diet, rats showed progressive increases in body weight, energy intake, abdominal fat deposition, and abdominal circumference along with impaired glucose tolerance, dyslipidemia, hyperinsulinemia, and increased plasma leptin and malondialdehyde concentrations. Cardiovascular signs included increased systolic blood pressure and endothelial dysfunction together with inflammation, fibrosis, hypertrophy, increased stiffness, and delayed repolarization in the left ventricle of the heart. The liver showed increased wet weight, fat deposition, inflammation, and fibrosis with increased plasma activity of liver enzymes. The kidneys showed inflammation and fibrosis, whereas the pancreas showed increased islet size. In comparison with other models of diabetes and obesity, this diet-induced model more closely mimics the changes observed in human metabolic syndrome.     

The role of aspirin in cardiovascular diseases--forgotten benefits?

The increasing burden of cardiovascular diseases in developed, as well as developing countries, underscores the need for the more widespread and appropriate use of aspirin in secondary prevention of occlusive vascular events during acute evolving myocardial infarction (MI) and in primary prevention. Aspirin should be far more widely used in a wide range of patients who have suffered a prior occlusive vascular event and in all patients suffering acute MI or occlusive stroke. Finally, in primary prevention, aspirin should be considered for individuals whose 10-year risks of a coronary event are > or = 10%, as an adjunct not alternative to the management of other risk factors. The more widespread and appropriate use of aspirin will avoid many premature deaths in secondary prevention and MIs in primary prevention.     

GQ-130, a novel analogue of thiazolidinedione,improves obesity-induced metabolic alterations in rats: Evidence for the involvement of PPARβ/δ pathway

The present investigation aimed to characterize the effect of a short-time treatment with a new thiazolidinedione (TZD) derivative, GQ-130, on metabolic alterations in rats fed a high-fat diet (HFD). We investigated whether metabolic alterations induced by GQ-130 were mediated though a mechanism that involves PPARβ/δ transactivation. Potential binding and transactivation of PPARα, PPARβ/δ or PPARγ by GQ-130 were examined through cell transactivation, 8-anilino-1-naphthalenesulfonic acid (ANS) fluorescence quenching assays and thermal shift assay. For in vivo experiments, male 8-week-old Wistar rats were divided into three groups fed for 6 weeks with: (a) a standard rat chow (14% fat) (control group), (b) a HFD (57.8% fat) alone (HFD group), or (c) a HFD associated with an oral treatment with GQ-130 (10 mg/kg/d) during the last week (HFD-GQ group). In 293T cells, unlike rosiglitazone, GQ-130 did not cause significant transactivation of PPARγ but was able to activate PPARβ/δ by 153.9 folds in comparison with control values (DMSO). Surprisingly, ANS fluorescence quenching assay reveals that GQ-130 does not bind directly to PPARβ/δ binding site, a finding that was further corroborated by thermal shift assay which evaluates the thermal stability of PPARβ/δ in the presence of GQ-130. Compared to the control group, rats of the HFD group showed obesity, increased systolic blood pressure (SBP), insulin resistance, impaired glucose intolerance, hyperglycaemia, and dyslipidaemia. GQ-130 treatment abolished the increased SBP and improved all metabolic dysfunctions observed in the HFD group. Oral treatment with GQ-130 was effective in improving HFD-induced metabolic alterations probably through a mechanism that involves PPARβ/δ activation.     

Submaximal PPARγ activation and endothelial dysfunction: new perspectives for the management of cardiovascular disorders

PPARγ activation plays an important role in glucose metabolism by enhancing insulin sensitization. PPARγ is a primary target for thiazolidinedione-structured insulin sensitizers like pioglitazone and rosiglitazone employed for the treatment of type 2 diabetes mellitus. Additionally, PPARγ activation inhibits adhesion cascades and detrimental vascular inflammatory events. Importantly, activation of PPARγ plays a distinctive role in regulating the physiology and expression of endothelial nitric oxide synthase (eNOS) in the endothelium, resulting in enhanced generation of vascular nitric oxide. The PPARγ activation-mediated vascular anti-inflammatory and direct endothelial functional regulatory actions could, therefore, be beneficial in improving the vascular function in patients with atherosclerosis and hypertension with or without diabetes mellitus. Despite the disappointing cardiac side effect profile of rosiglitazone-like PPARγ full agonists, the therapeutic potential of novel pharmacological agents targeting PPARγ submaximally cannot be ruled out. This review discusses the potential regulatory role of PPARγ on eNOS expression and activation in improving the function of vascular endothelium. We argue that partial/submaximal activation of PPARγ could be a major target for vascular endothelial functional improvement. Interestingly, newly synthesized partial agonists of PPARγ such as balaglitazone, MBX-102, MK-0533, PAR-1622, PAM-1616, KR-62776 and SPPARγM5 are devoid of or have a reduced tendency to cause the adverse effects associated with full agonists of PPARγ. We propose that the vascular protective properties of pharmacological agents, which submaximally activate PPARγ, should be investigated. Moreover, the therapeutic opportunities of agents that submaximally activate PPARγ in preventing vascular endothelial dysfunction (VED) and VED-associated cardiovascular disorders are discussed.     

The role of β-blockers in the management of hypertension: An Asian perspective

Abstract

Following publication of the National Institute of Clinical Excellence (NICE) Guidelines in 2006, the use of β-blockers as first-line therapy in hypertension has been somewhat controversial. However, a recent reappraisal of the European Society of Hypertension guidelines highlights that these agents exhibit similar BP lowering efficacy to other classes of agents, prompting a re-examination of the utility of these agents in various patient populations. The authors felt that it is important to address this controversy and provide an Asian perspective on the place of β-blockers in current clinical practice and the benefits of β-blockade in selected patient populations. In addition to their use as a potential first-line therapy in uncomplicated hypertension, β-blockers have a particular role in patients with hypertension and comorbidities such as heart failure or coronary artery disease, including those who had a myocardial infarction. One advantage which β-blockers offer is the additional protective effects in patients with prior cardiovascular events. Some of the disadvantages attributed to β-blockers appear more related to the older drugs in this class and further appraisal of the efficacy and safety profile of newer β-blockers will lend support to the current guideline recommendations in Asian countries and encourage increased appropriate use of β-blockade in current clinical practice within Asia.     

The role of β-blockers in the management of hypertension: an Asian perspective

Following publication of the National Institute of Clinical Excellence (NICE) Guidelines in 2006, the use of β-blockers as first-line therapy in hypertension has been somewhat controversial. However, a recent reappraisal of the European Society of Hypertension guidelines highlights that these agents exhibit similar BP lowering efficacy to other classes of agents, prompting a re-examination of the utility of these agents in various patient populations. The authors felt that it is important to address this controversy and provide an Asian perspective on the place of β-blockers in current clinical practice and the benefits of β-blockade in selected patient populations. In addition to their use as a potential first-line therapy in uncomplicated hypertension, β-blockers have a particular role in patients with hypertension and comorbidities such as heart failure or coronary artery disease, including those who had a myocardial infarction. One advantage which β-blockers offer is the additional protective effects in patients with prior cardiovascular events. Some of the disadvantages attributed to β-blockers appear more related to the older drugs in this class and further appraisal of the efficacy and safety profile of newer β-blockers will lend support to the current guideline recommendations in Asian countries and encourage increased appropriate use of β-blockade in current clinical practice within Asia.     

The role of immunotherapy in Guillain-Barré syndrome: understanding the mechanism of action

INTRODUCTION: Guillain-Barré syndrome (GBS) is the most frequent cause of acute flaccid paralysis and, despite treatment, there continues to be an associated mortality and severe disability ranging from 9 to 17%. This article reviews the rationale behind the existing immunotherapy in GBS and discusses the future direction that work in this area should follow. AREAS COVERED: The pathogenesis of GBS and the current evidence for the different forms of immunotherapy in GBS are reviewed. The proposed mechanism of action of each treatment--(steroids, plasma exchange and intravenous immunoglobulin (IVIG))--in GBS are discussed. EXPERT OPINION: Both plasma exchange and IVIG are equally effective in GBS although the latter is preferred in view of its ease of access and lower rates of complications. Although not clinically established, there may be a role for the concomitant use of steroids with IVIG and, in patients with severe disease and poor prognostic scores, plasma exchange followed by IVIG or two successive IVIG may prove beneficial.     

The role of immunotherapy in Guillain-Barré syndrome: understanding the mechanism of action

Introduction: Guillain-Barré syndrome (GBS) is the most frequent cause of acute flaccid paralysis and, despite treatment, there continues to be an associated mortality and severe disability ranging from 9 to 17%. This article reviews the rationale behind the existing immunotherapy in GBS and discusses the future direction that work in this area should follow.

Areas covered: The pathogenesis of GBS and the current evidence for the different forms of immunotherapy in GBS are reviewed. The proposed mechanism of action of each treatment – (steroids, plasma exchange and intravenous immunoglobulin (IVIG)) – in GBS are discussed.

Expert opinion: Both plasma exchange and IVIG are equally effective in GBS although the latter is preferred in view of its ease of access and lower rates of complications. Although not clinically established, there may be a role for the concomitant use of steroids with IVIG and, in patients with severe disease and poor prognostic scores, plasma exchange followed by IVIG or two successive IVIG may prove beneficial.     

The case for peripheral CB₁ receptor blockade in the treatment of visceral obesity and its cardiometabolic complications

In this review, we consider the role of endocannabinoids and cannabinoid-1 (CB(1)) cannabinoid receptors in metabolic regulation and as mediators of the thrifty phenotype that underlies the metabolic syndrome. We survey the actions of endocannabinoids on food intake and body weight, as well as on the metabolic complications of visceral obesity, including fatty liver, insulin resistance and dyslipidemias. Special emphasis is placed on weighing the relative importance of CB(1) receptors located in peripheral tissues versus the central nervous system in mediating the metabolic effects of endocannabinoids. Finally, we review recent observations that indicate that peripherally restricted CB(1) receptor antagonists retain efficacy in reducing weight and improving metabolic abnormalities in mouse models of obesity without causing behavioural effects predictive of neuropsychiatric side effects in humans.     

The perceived role and skills of pharmacists in asthma management after in‐house training

Objective: To evaluate perceived roles and skills of pharmacists in asthma management before and after a training intervention that consisted of six inhouse training sessions. Method: Altogether 315 pharmacists in the intervention group and 121 pharmacists in the control group participated in the study. The data on study variables were collected by a questionnaire during the first and last training sessions.Main outcome measures: Pharmacists' perceptions of their role, perceived skills, estimates of patients receiving counselling and experienced problems.Results: Based on their ratings for 16 topics, the pharmacists' perceptions about their role in counselling asthma patients remained rather stable. Handling of the inhalers and inhalation technique were considered as the most important aspects of counselling and issues dealing with the disease were regarded as the least important. Using a selfrated scale (410 scale), pharmacists' perceived counselling skills improved in the intervention group (6.5 vs 7.6), but not in the control group (6.5 vs 6.4). In the intervention group, the pharmacists' estimates of the proportion of new users of asthma medicines receiving counselling increased from 48% to 61% and that of old users from 18% to 26%. Before the training, the most commonly experienced problem in counselling was the pharmacists' lack of knowledge and skills. After the training, pharmacists experienced problems mainly with communication. Conclusion: When pharmacists are included in the support system for any patient group, their capabilities of fulfilling their role have to be assessed. In particular, communication skills and outcomeoriented counselling require attention.     

TGF-β: friend or foe? The role of TGF-β/SMAD signaling in epigenetic silencing of ovarian cancer and its implication in epigenetic therapy

Importance of the field: The TGF-β signaling pathway plays an important role in regulating numerous cellular processes including growth inhibition of ovarian surface epithelial (OSE) cells. However, epithelial ovarian cancer is refractory to the inhibitory functions of TGF-β, and yet TGF-β induces metastasis or epithelial–mesenchymal transition (EMT) in advanced ovarian cancer. How TGF-β plays a certain role in one cell but a different role in its malignant counterpart is not fully understood.

Areas covered in this review: The role of TGF-β/SMAD signaling both in normal OSE cells and ovarian cancer as well as how dysregulation of this signaling pathway leads to epigenetic silencing of its downstream targets in ovarian neoplasias are reviewed. The therapeutic implication of this signaling pathway in epigenetic therapy of ovarian cancer are also discussed.

What the reader will gain: The reader will gain insight on how dysregulation of TGF-β signaling alters promoter methylation and histone modifications of TGF-β downstream targets in ovarian cancer.

Take home message: Disruption of TGF-β/SMAD signaling leads to epigenetic silencing of its target genes transiently through histone modifications but permanently by promoter hypermethylation. Targeting the TGF-β signaling pathway may be a novel therapeutic strategy in ovarian cancer.     

Nickel-induced down-regulation of ΔNp63 and its role in the proliferation of keratinocytes

Epidemiological, animal, and cell studies have demonstrated that nickel compounds are human carcinogens. The mechanisms of their carcinogenic actions remain to be investigated. p63, a close homologue of the p53 tumor suppressor protein, has been linked to cell fate determination and/or maintenance of self-renewing populations in several epithelial tissues, including skin, mammary gland, and prostate. ΔNp63, a dominant negative isoform of p63, is amplified in a variety of epithelial tumors including squamous cell carcinomas and carcinomas of the prostate and mammary glands. The present study shows that nickel suppressed ΔNp63 expression in a short-time treatment (up to 48 h). Nickel treatment caused activation of NF-κB. Blockage of NF-κB partially reversed nickel-induced ΔNp63 suppression. Nickel decreased interferon regulatory factor (IRF) 3 and IRF7, IKKε, and Sp100. Over-expression of IRF3 increased ΔNp63 expression suppressed by nickel. Nickel was able to activate p21, and its activation was offset by the over-expression of ΔNp63. In turn, elevated p63 expression counteracted the ability of nickel to restrict cell growth. The present study demonstrated that nickel decreased interferon regulatory proteins IRF3 and IRF7, and activated NF-κB, resulting in ΔNp63 suppression and then p21 up-regulation. ΔNp63 plays an important role in nickel-induced cell proliferation.     

ARBs and ACEis together in the treatment of hypertension and its complications? current practical recommendations

Importance of the field: Arterial hypertension is highly prevalent in the general population. Its contribution to the development and evolution of cardiovascular and renal disease is well recognized. Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) have demonstrated favorable effects on cardiovascular and renal prognosis; however, some limitations have been described, for example angiotensin and aldosterone breakthrough.

Areas covered in this review: This article describes several therapeutical strategies that can be administered with an ACEi or ARB, such as the direct renin inhibitors or the aldosterone receptor antagonists.

What the reader will gain: The addition of an ACEi to an ARB or vice versa was initially considered as a way of obtaining a stronger suppression of the renin–angiotensin–aldosterone system (RAAS), but recent evidence has shown that the combination of the two classes of drugs does not seem to afford the expected increase in benefit.

Take home message: RAAS suppression with monotherapy is associated with beneficial cardiovascular effects, but has several limitations. Direct renin inhibitors and aldosterone receptor antagonists will increase the benefits of dual blockade. We need randomized trial data supporting reduction of cardiovascular events with an adequate safety profile using combination therapies.     

GABAA ρ receptor mechanisms in the rat amygdala and its role in the modulation of fear and anxiety

Rationale  

Accumulating evidence for the presence of GABA_A ρ receptors within the amygdala which differ from other members of the GABA_A receptor family in both subunit composition and functional properties has been recently obtained.