Antagonistic activity of tamsulosin against human vascular alpha1-adrenergic receptors

Discovery of Novel pERK1/2- or β-Arrestin-Preferring 5-HT1A Receptor-Biased Agonists: Diversified Therapeutic-like versus Side Effect Profile

Novel 1-(1-benzoylpiperidin-4-yl)methanamine derivatives with high affinity and selectivity for serotonin 5-HT_1A receptors were obtained and tested in four functional assays: ERK1/2 phosphorylation, adenylyl cyclase inhibition, calcium mobilization, and β-arrestin recruitment. Compounds 44 and 56 (2-methylaminophenoxyethyl and 2-(1H-indol-4-yloxy)ethyl derivatives, respectively) were selected as biased agonists with highly differential “signaling fingerprints” that translated into distinct in vivo profiles. In vitro, 44 showed biased agonism for ERK1/2 phosphorylation and, in vivo, it preferentially exerted an antidepressant-like effect in the Porsolt forced swimming test in rats. In contrast, compound 56 exhibited a first-in-class profile: it preferentially and potently activated β-arrestin recruitment in vitro and potently elicited lower lip retraction in vivo, a component of “serotonergic syndrome”. Both compounds showed promising developability properties. The presented 5-HT_1A receptor-biased agonists, preferentially targeting various signaling pathways, have the potential to become drug candidates for distinct central nervous system pathologies and possessing accentuated therapeutic activity and reduced side effects.

Cherry angioma: A case-control study

BACKGROUND:

Cherry angiomas (CAs) are very common asymptomatic vascular skin lesions. There are only a few studies on CAs in the literature and those assessing risk factors of CAs are scarce. The aim of our study was to determine risk factors for the development of CAs.

MATERIALS AND METHODS:

A case–control study was conducted at a tertiary care center in Riyadh, Saudi Arabia. Patients underwent a full-body examination for CAs. Demographics and other data including medical history and medications were extracted from electronic medical records.

RESULTS:

A total of three hundred patients were enrolled: one hundred cases with at least five CAs and two hundred controls without CAs. Bivariate analysis identified benign prostatic hyperplasia (odds ratio [OR]: = 2.591), malignancy (OR = 2.567), tamsulosin (OR = 3.171), and clopidogrel (OR = 0.321) as statistically significant associations. After multivariate logistic regression analysis, only tamsulosin (OR = 3.475, P = 0.009) and clopidogrel (OR = 0.281, P = 0.028) were found to be independent risk factors for CAs. Malignancies tended to be more associated with CAs, but this did not reach statistical significance (P = 0.07).

CONCLUSION:

Tamsulosin is a possible risk factor for the development of CAs. Clopidogrel seems to have a protective role preventing the development of CAs.

[From lab to clinical activity: adrenergic receptors and human uro-genital tissues]

BACKGROUND

Nowadays translational medicine is acquiring a more and more important role in connecting laboratory experimental results on human tissues to clinical findings and drug employment. We want to underline the importance of in vitro studies, which have been extensively performed on animal organs, but few studies have been performed on human tissues. Nevertheless, a more accurate result when compared to the in vivo use of drugs can be given only by testing the very same human tissues in a lab. We related clinical treatments of different pathologies with the results obtained in laboratory studying in vitro fragments of human organs extracted during surgery exposed to different mediators and drugs.

METHODS

Fragments of urethers, bladder (detrusorial muscle and bladder neck muscle fibers), corpora cavernosa, and vas deferens were extracted during demolitive surgery trying not to traumatize the tissue, in order to keep it alive and not to ruin its contractile fibers. The fragments were then put into polisaline solution and, once in the laboratory, fixed on suitable isolated organ support, fixed at one side of the thermostatic pool and on the other side connected to a digital monitoring system. The contractility was then studied after adding different mediators.

RESULTS

The urethers have shown a stronger response to NE and PGF2a, with a different contractility in their distal part due to a major concentration of alpha-receptors; the bladder neck has also shown a strong contractile response to NE and PGF2a, and is inhibited by alpha-blockers; the bladder detrusor, instead, responds to ACH (acetylcholine) and PGF2a; the vas deferens shows a different type of contractility in the prostatic part compared to the epididimary part when stimulated with noradrenaline and PGF2a; the corpora cavernosa respond to NE and PGF2a.

CONCLUSIONS

The results obtained after stimulating the fragments can explain and prove the receptorial activity of inner mediators and of commonly used drugs which have, for years, been used empirically; the simplicity and repetitivity of the method can be considered and used not only to research the physiological functioning of different organs, but also the functioning of new drugs before testing them on patients, being more reliable and accurate than tests on animal tissues. This experimental work has shown that using human tissues in testing specific mediators is the most reliable laboratory method.

Tamsulosin: a review of its pharmacology and therapeutic efficacy in the management of lower urinary tract symptoms

Tamsulosin is a subtype-selective alpha(1A)- and alpha(1D )-adrenoceptor antagonist. alpha(1)-Receptors predominate in the prostate gland, prostatic capsule, prostatic urethra and bladder, and the relaxation of prostate and bladder smooth muscles is associated with improved maximal urine flow (Q(max)) and alleviation of lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia (BPH). Tamsulosin 0.4 mg once daily in a modified-release formulation increased Q(max) and improved symptom scores relative to baseline to a greater extent than placebo in 12- and 13-week double-blind, randomised, multicentre, clinical trials in patients with LUTS, with statistical significance between treatments for Q(max) values in two of three published US and European studies. Tamsulosin is effective in patients with mild to severe LUTS associated with BPH, in patients with diabetes mellitus and in the elderly, and does not interfere with concomitant antihypertensive therapy. Pooled data based on patients receiving tamsulosin 0.4 or 0. 8mg once daily indicate maintenance of efficacy for up to 6 years. Tamsulosin 0.4 mg once daily was of similar efficacy to alfuzosin 2.5 mg three times daily, with less tendency to cause hypotensive effects, in a double-blind, randomised 12-week trial. Benefit of the drug has also been shown in patients with acute urinary retention or chronic abacterial prostatitis, those receiving high energy transurethral microwave thermotherapy, and in patients with prostate cancer with radiation-induced urethritis. Dizziness and abnormal ejaculation are stated to be the most common adverse events, with asthenia, postural hypotension and palpitations being seen less frequently (1 to 2% incidence), in patients receiving tamsulosin 0.4 mg once daily. Tamsulosin has not been associated with clinically significant changes in blood pressure in clinical trials.

CONCLUSION

The alpha(1A)- and alpha(1D)-adrenoceptor antagonist tamsulosin, given at a dosage of 0.4 mg once daily in a modified-release formulation, is effective and well tolerated in the treatment of LUTS associated with BPH. Although the drug has been directly compared to date with one other agent only, data show overall that tamsulosin clearly offers advantages over other alpha(1)-adrenoceptor antagonists in terms of the need for a single daily dose only, and its low potential for hypotensive effects or interference with concomitant antihypertensive therapy. Dosage titration at the start of treatment is not necessary. Tamsulosin has a rapid onset of action and is effective in patients with moderate or severe symptoms. The drug is therefore a valuable therapeutic option, with both demonstrated and potential advantages over older nonselective agents, in the management of patients with LUTS associated with BPH.

Tamsulosin: an update of its role in the management of lower urinary tract symptoms

Tamsulosin is a selective alpha1A- and alpha1D-adrenoceptor antagonist. These alpha1-receptors are predominant in the prostate, prostatic capsule, prostatic urethra and bladder. The relaxation of prostate and bladder smooth muscles may result in improvement in maximum urine flow (Qmax) and reduction of lower urinary tract symptoms (LUTS). Tamsulosin 0.4 and 0.8 mg/day in a modified-release formulation was significantly more effective than placebo in large (n >250) double-blind, randomised, multicentre, 12- to 13- week clinical trials in patients with LUTS. A greater increase in Qmax from baseline was seen in patients receiving tamsulosin 0.4 or 0.8 mg/day (1.4 to 1.79 ml/sec from a baseline of 9.46 to 10.7 ml/sec) than in placebo recipients (0.4 to 0.93 ml/sec from a baseline of 9.75 to 10.4 ml/sec); the between-group difference was significant in two of three studies. Tamsulosin 0.4 or 0.8 mg/day improved total Boyarsky symptom scores from baseline by a significantly greater extent (by 3.0 to 5.2 points from a baseline of 9.5 to 11.1 points) than placebo (1.9 to 3.2 points from a baseline of 9.3 to 11.0 points). In noncomparative extension studies, the improvement in efficacy parameters with tamsulosin treatment was maintained for up to 4 years. Tamsulosin is effective in patients with mild to severe LUTS, patients with diabetes mellitus or those aged > or = 65 years and does not interfere with the antihypertensive action of nifedipine, enalapril or atenolol. Tamsulosin 0.4 mg/day for 12 weeks and tamsulosin 0.2 mg/day for 4 weeks were as effective as alfuzosin 2.5mg three times daily and terazosin 2 mg/day, respectively, in improving Qmax and symptom scores in randomised comparative trials. With the exception of a numberically greater incidence of abnormal ejaculation, dizziness and rhinitis, the incidence of adverse events with tamsulosin 0.4 mg/day was similar to that seen with placebo in randomised, double-blind studies. The overall incidence of symptoms indicative of orthostasis was 1.4% with tamsulosin 0.4 or 0.8 mg/day treatment. Tamsulosin had less effect on blood pressure than alfuzosin or terazosin.

CONCLUSION

Tamsulosin, an alpha1-adrenoceptor antagonist, has a well established place in the treatment of LUTS and has a tolerability profile similar to that of placebo (apart from a higher incidence of abnormal ejaculation, dizziness and rhinitis). Comparative data have shown tamsulosin to be as effective as other alpha1-adrenoceptor antagonists at increasing Qmax and improving symptom scores. However, tamsulosin is unlikely to produce orthostatic hypotensive adverse effects or interfere with concomitant antihypertensive drug therapy. Therefore, tamsulosin is a useful therapeutic option in the management of patients with moderate to severe LUTS.