Renin-angiotensin antagonists: therapeutic effects beyond blood pressure control?

Guidelines for the treatment of hypertension allow a wide range of choices to the physicians; however some differences are present about the preferred drugs to start treatment. The most important aim remains an adequate decrease of blood pressure, something not perfectly obtained in the general population, but some classes of anti-hypertensive drugs could show protective effects on cardiovascular events, which are independent from blood pressure levels (the so called effects beyond blood pressure control). In this context antagonists of the renin-angiotensin system may represent an important help for the physicians, keeping in mind the preclinical studies showing the central role of the renin-angiotensin system not only in the regulation of blood pressure but also in the atherothrombotic processes. The demonstration of an additional favourable effect of renin-angiotensin system blockers is not so obvious and frequently debated in the literature. Evidence-based medicine suggests that in patients at moderate/high cardiovascular risk it is difficult to have clear evidence of a specific advantage of some drug classes with respect to the others. However renin-angiotensin system blockers maintain compelling indications in particular cardiovascular situations; in addition analysis of intermediate end points, such as microalbuminuria, left ventricular hypertrophy, and arterial stiffness, gives further support to a drug-based anti-hypertension strategy. Last but not least, the optimal safety profile of these drugs, in particular of angiotensin II receptor blockers and renin inhibitors, allows their use in the very early stage of the hypertensive situation, as suggested by recent clinical trials.     

Is combination therapy with lamivudine and interferon-alpha superior to monotherapy with either drug?

For the treatment of chronic hepatitis B (CHB) two drugs have been licensed world-wide: interferon-alpha (IFN) and lamivudine. Both drugs significantly increase the hepatitis B e-antigen (HBeAg) seroconversion rate, but a sustained treatment response occurs in less than 40% of patients. To explore whether there is an additional benefit of combining these two drugs, we reviewed the literature on lamivudine-IFN combination therapy in comparison to the two monotherapies in compensated, HBeAg-positive, CHB patients. We focussed on two clinically relevant outcome measures: HBeAg seroconversion, and change in liver histology. Candidates for lamivudine-IFN combination therapy were, previously untreated, patients with moderately elevated alanine aminotransferase (ALT). Such regimen should still be considered experimental. Viral kinetics may provide insight into how long therapy should be continued; prolongation of therapy to 52 weeks currently appears a reasonable approach. According to principles of anti-viral therapy today, simultaneously dosing of both drugs is to be preferred, since rapid maximal virus suppression is thought to be essential to prevent drug resistance and enhance seroconversion. From an immunological point of view, pre-treatment with lamivudine or IFN may alter the virus-host balance and set the stage for the other drug to enhance the effect of treatment. Further clinical research on lamivudine-IFN combination therapy appears warranted.     

Switching patients with uncontrolled hypertension on amlodipine 10 mg to single-pill combinations of telmisartan and amlodipine: results of the TEAMSTA-10 study

Abstract

Objective:

To evaluate the efficacy and safety of two different strengths of single-pill combinations of the angiotensin II receptor blocker telmisartan 40 or 80?mg (T40 or T80) and the calcium channel blocker amlodipine 10?mg (A10) compared with that of A10 monotherapy in a hypertensive patient population whose blood pressure was not controlled by A10.     

Renin–angiotensin–aldosterone responsiveness to low sodium and blood pressure reactivity to angiotensin-II are unrelated to cholesteryl ester transfer protein mass in healthy subjects

Background: The blood pressure increase associated with the cholesteryl ester transfer protein (CETP) inhibitor, torcetrapib is probably attributable to an off-target effect but it is unknown whether activation of the renin–angiotensin–aldosterone system (RAAS) may be related to variation in the plasma CETP level. We questioned whether the plasma CETP level would affect RAAS responsiveness to low sodium diet and the blood pressure response to angiotensin-II infusion in healthy subjects. Methods: RAAS parameters and blood pressure were determined during liberal sodium diet (200 mmol/24 h) and low sodium diet (50 mmol/24 h) in 67 healthy men. Blood pressure response to incremental angiotensin-II infusion was assessed in 34 subjects during liberal sodium diet. Correlation analysis was performed to test whether RAAS responsiveness and blood pressure were related to plasma CETP mass, high-density lipoprotein-cholesterol (HDL-C) and apolipoprotein A-I measured during liberal sodium diet. Results: CETP mass ranged from 1.29 to 2.95 mg/l. No significant differences in (changes) in mean arterial pressure, aldosterone and active plasma renin concentration in response to low sodium were observed between the lowest and highest tertiles of CETP mass, HDL-C and apolipoprotein A-I. These outcome variables were also not significantly correlated with CETP, HDL-C and apolipoprotein A-I, except for a modest relation of aldosterone measured during low sodium with apolipoprotein A-I (r = 0.28, p = 0.022). Blood pressure response to angiotensin-II was similar between CETP tertiles. Conclusions: Mineralocorticoid and blood pressure responsiveness to dietary salt intake are not significantly related to physiological interindividual differences in plasma CETP. We suggest that a lower CETP mass does not exert adverse effects on blood pressure regulation.     

Thrombolytic therapy for acute ischaemic stroke: what can we do to improve outcomes?

Constant efforts are being made in the stroke community to aim for maximum benefit from thrombolytic therapy since the approval of intravenous recombinant tissue plasminogen activator (rt-PA; alteplase) for the management of acute ischaemic stroke. However, fear of symptomatic haemorrhage secondary to thrombolytic therapy has been a major concern for treating physicians. Certain imaging and clinical variables may help guide the clinician towards better treatment decision making. Aggressive management of some predictive variables that have been shown to be surrogate outcome measures has been related to better clinical outcomes. Achieving faster, safer and complete recanalization with evolving endovascular techniques is routinely practiced to achieve better clinical outcomes. Selection of an 'ideal candidate' for thrombolysis can maximize functional outcomes in these patients. Although speed and safety are the key factors in acute management of stroke patients, there must also be a systematic and organized pattern to assist the stroke physician in making decisions to select the 'ideal candidate' for treatment to maximize results.     

Inhaled corticosteroids as combination therapy with β-adrenergic agonists in airways disease: present and future

Inhaled corticosteroid (ICS) therapy in combination with long-acting β-adrenergic agonists represents the most important treatment for chronic airways diseases such as asthma and chronic obstructive pulmonary disease (COPD). ICS therapy forms the basis for treatment of asthma of all severities, improving asthma control, lung function and preventing exacerbations of disease. Use of ICS has also been established in the treatment of COPD, particularly symptomatic patients, who experience useful gains in quality of life, likely from an improvement in symptoms such as breathlessness and in reduction in exacerbations, and an attenuation of the yearly rate of deterioration in lung function. The addition of long-acting β-agonist (LABA) therapy with ICS increases the efficacy of ICS effects in moderate-to-severe asthma. Thus, a 800 μg daily dose of the ICS budesonide reduced severe exacerbation rates by 49% compared to a low dose of 200 μg daily, and addition of the LABA formoterol to budesonide (800 μg) led to a 63% reduction. In COPD, the effects of ICS are less prominent but there are beneficial effects on the decline in FEV₁ and the rate of exacerbations. A reduction in the rate of decline in FEV₁ of 16 ml/year with a 25% reduction in exacerbation rate has been reported with the salmeterol and fluticasone combination. A non-significant 17.5% reduction in all-cause mortality rate with ICS and LABA is reported. Chronic inflammation is a feature of both asthma and COPD, although there are site and characteristic differences. ICS targets this inflammation although this effect of ICS is less effective in patients with severe asthma and with COPD; however, addition of LABA may potentiate the anti-inflammatory effects of ICS. An important consideration is the presence of corticosteroid insensitivity in these patients. Currently available ICS have variably potent binding activities to specific glucocorticoid receptors, leading to inhibition of gene expression by either binding to DNA and inducing anti-inflammatory genes or by repressing the induction of pro-inflammatory mediators. Local side effects of ICS include oral candidiasis, hoarseness and dysphonia, while systemic side effects, such as easy bruising and reduction in growth velocity or bone mineral densitometry, are usually restricted to doses above maximally recommended doses. Use of LABA alone in patients with asthma increases the risk of asthma-related events including deaths, but this is less observed with the combination of ICS and LABA. Therefore, use of LABA alone is not recommended for asthma therapy. Future progress in ICS development will be characterised by the introduction of ICS with greater efficacy with a limited side-effect profile, and by longer-acting ICS that can be used in combination with once-daily LABAs. Other agents that could improve the efficacy of corticosteroids or reverse corticosteroid insensitivity may be added to ICS. ICS in combination with LABAs will continue to remain the main focus of treatment of airways diseases.     

The effect of fibrate–statin combination therapy on cardiovascular events: a retrospective cohort analysis

Abstract

Objective:

To investigate the long-term efficacy of fibrate–statin combination therapy on cardiovascular events as opposed to lipid levels.     

Enhanced blood–brain barrier transport of vinpocetine by oral delivery of mixed micelles in combination with a message guider

The blood–brain barrier represents an insurmountable obstacle for the therapy of central nervous system related diseases. Polymeric micelles have many desirable properties for brain targeting by oral delivery, but the stability and targeting efficiency needs to be improved. In this study, it was demonstrated that binary micelle system can compensate the drawbacks of mono system by preparing mixed micelles in combination with PEG-based copolymers. Here, we explored a brain targeting drug delivery system via facile approaches using P123 based mixed micelles in combination with a message guider from traditional Chinese medicine, borneol, for oral delivery. With higher drug-loading, improved stability, prolonged in vitro release profile, increased bioavailability and enhanced brain targeting effect was achieved after peroral delivery of the mixed micelles. More importantly, without extra structure modification for active targeting, it was demonstrated for the first time that oral delivery of vinpocetine loaded mixed micelles together with borneol is an effective way to increase drug concentration in the brain and the targeting efficiency is borneol dose dependent. Such a “simple but effective” modality may shed light on the potential use of polymeric micelles in combination with a message drug to achieve drug brain targeting or other targeting sites via oral delivery.     

Long-acting beta 2-adrenoceptor agonists or tiotropium bromide for patients with COPD: is combination therapy justified?

Bronchodilators are the mainstay of therapy for patients with established chronic obstructive pulmonary disease (COPD) but, at present, the majority of patients use short-acting agents. There is increasing evidence that long-acting agents, such as the beta(2)-adrenoceptor agonists salmeterol and formeterol, and the new anticholinergic tiotropium bromide provide a better therapeutic option. In the treatment of COPD, long-acting beta(2)-adrenoceptor agonists (LABAs) given twice daily cause the same degree of bronchodilation as tiotropium bromide given once daily. Combined use of an inhaled LABA with tiotropium bromide should provide important therapeutic benefits, as these drugs have distinct and complementary pharmacological actions in the airways. Although clinical trials of this combination have not been performed, clinical experience with Combivent, a combination of a short-acting beta(2)-adrenoceptor agonist (salbutamol) and a short-acting anticholinergic (ipratropium bromide), in COPD is encouraging because the bronchodilation produced is of a magnitude greater than that of either component alone. However, because LABAs are given twice daily but tiotropium bromide is required only once daily, the challenge is to develop a combined inhaler that can be employed on a daily basis.     

Reduction-responsive PEtOz-SS-PCL micelle with tailored size to overcome blood–brain barrier and enhance doxorubicin antiglioma effect

A series of novel reduction-responsive micelles with tailored size were designed and prepared to release doxorubicin (DOX) for treating glioma, which were developed based on amphiphilic block copolymer poly (2-ethyl-2-oxazoline)-b-poly (ε-caprolactone) (PEtOz-SS-PCL) and the micelle size could be regulated by designing the polymer structure. The DOX-loaded PEtOz-SS-PCL micelles had small size and rapid drug release in reductive intracellular environments. Biodistribution and in vivo imaging studies in C6 glioma mice tumor model showed that DOX loaded PEtOz-SS-PCL43 micelles with the smallest size had superior accumulation and fast drug release in tumor sites. In vivo antitumor activity demonstrated that DOX-loaded PEtOz-SS-PCL43 micelles improved antitumor efficacy in contrast to PEtOz-SS-PCL micelles with larger size toward the orthotopic C6-Luci cells-bearing mice. This study shows great potential in tailoring the micelle size and introducing the responsive bonds or compartment for intracellular drug delivery and release in glioma treatment by designing the architecture of the polymer.     

Endocytosis at the blood–brain barrier: From basic understanding to drug delivery strategies

The blood–brain barrier (BBB) protects the central nervous system (CNS) from potentially harmful xenobiotics and endogenous molecules. Anatomically, it comprises the brain microvasculature whose functionality is nevertheless influenced by associated astrocyte, pericyte and neuronal cells. The highly restrictive paracellular pathway within brain microvasculature restricts significant CNS penetration to only those drugs whose physicochemical properties afford ready penetration into hydrophobic cell membranes or are capable of exploiting endogenous active transport processes such as solute carriers or endocytosis pathways. Endocytosis at the BBB is an essential pathway by which the brain obtains its nutrients and affords communication with the periphery. The development of strategies to exploit these endocytic pathways for the purposes of drug delivery to the CNS is still an immature field although some impressive results have been documented with the targeting of particular receptors. This current article initially provides an overview of general endocytosis processes and pathways showing evidence of their functional existence within the BBB. Subsequent sections provide, in an entity-specific manner, comprehensive reviews on BBB transport investigations of endocytosis involving: transferrin and the targeting of the transferrin receptor; hormones; cytokines; cell penetrating peptides; microorganisms and toxins, and nanoparticles aimed at more effectively delivering drugs to the CNS.