New clinical evidence of silodosin, an α1A selective adrenoceptor antagonist, in the treatment for lower urinary tract symptoms

Evolving Role of Silodosin for the Treatment of Urological Disorders – A Narrative Review

Use of α-androgenic receptor blockers remains a mainstay therapeutic approach for the treatment of urological diseases. Silodosin is recommended over other α-blockers for the treatment of lower urinary tract symptoms (LUTS) and benign prostate hyperplasia (BPH), due to its high α_1A uroselectivity. Current research data suggest that silodosin is efficacious in the management of various urological diseases. Thus, we herein review the current evidence of silodosin related to its efficacy and tolerability and appraise the available literature that might ultimately aid in management of various urological conditions at routine clinical practice. Literature reveals that silodosin is beneficial in improving nocturia events related to LUTS/BPH. Silodosin exerts effect on relaxing muscles involved in detrusor obstruction, therefore prolonging the need for patients undergoing invasive surgery. Silodosin treatment, either as a monotherapy or combination, significantly improves International Prostate Symptom Score (IPSS) including both storage and voiding symptoms in patients with BPH/LUTS. Patients on other treatment therapies such as phosphodiesterase 5 inhibitors or other α-blockers are well managed with this drug. Steadily, silodosin has proved beneficial in the treatment of other urological disorders such as chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), overactive bladder/acute urinary retention (AUR), premature ejaculation (PE), and prostate cancer post brachytherapy-induced progression. In patients with distal ureteral stones, silodosin treatment is beneficial in decreasing stone expulsion time without affecting stone expulsion rate or analgesic need. Moreover, there were significant improvements in intravaginal ejaculation latency time, quality of life scores, and decrease in PE profile among patients with PE. Silodosin has also demonstrated promising results in increasing the likelihood of successful trial without catheter in patients with AUR and those taking antihypertensive drugs. Reports from Phase II studies have shown promising role of silodosin in the treatment of CP/CPPS as well as facilitating ureteral stone passage. From the robust data in this review, further silodosin treatment strategies in the management of different urological conditions need to be focused on.

Cell-based 3D bionic screening by mimicking the drug-receptor interaction environment in vivo

Most small-molecule drugs influence cell behavior through their interaction with one or more cellular proteins. The efficacy is unanticipated in the later stages of drug development if small-molecule drugs are discovered in the absence of a biological context. Bionic screening is an in vivo drug-receptor interaction platform that can identify small molecules with recognized activity, improving the likelihood of drug efficacy in the clinic. Here, we report the design of an innovative cell-based bionic screening system using 3D microcarrier cultures to simulate in vivo conditions and facilitate small-molecule drug discovery. Through its combination with HPLC/MS, the method can comprehensively identify small-molecule lead compounds in arbitrarily complex systems in an unbiased manner. In particular, cell-covered microcarriers provide a high-density of cells for affinity performance assessments in the absence of appreciable cell damage and maintain immunogenicity, the 3D structure of which is similar to tissue morphology in vivo, thereby mimicking in vivo drug-receptor interactions. The method is scalable, easy to handle, and requires minimal optimization across a range of different cell lines to realize high-throughput drug screening for the corresponding diseases. This provides a valuable tool for lead compound discovery in more physiologically relevant systems and may address the lack of clinically available drugs.

Impact of the Preoperative C-reactive Protein to Albumin Ratio on the Long-Term Outcomes of Hepatic Resection for Intrahepatic Cholangiocarcinoma

Objective:

The present study aimed to investigate the impact of preoperative C-reactive protein to albumin (CRP/Alb) ratio on the long-term outcomes of patients with intrahepatic cholangiocarcinoma (ICC).

Methods:

82 patients who underwent hepatic resection for mass-forming type of ICC were evaluated. The relationship between preoperative CRP/Alb ratio and survival outcomes was investigated.

Results:

The optimal cutoff value of CRP/Alb ratio for assessing overall survival (OS) was determined as 0.089. Univariate analysis for recurrence-free survival (RFS) showed that CRP/Alb ratio >0.089, carbohydrate antigen 19-9 (CA 19-9) >37 U/mL, lymph node metastasis, vascular invasion, and multiple tumors were significantly associated with postoperative recurrence. On multivariate analysis, the independent prognostic factors identified were CRP/Alb ratio >0.089 (p < 0.001), lymph node metastasis (p = 0.006), and multiple tumors (p < 0.001). Univariate analysis for OS showed that CRP/Alb ratio >0.089, CA 19-9 >37 U/mL, lymph node metastasis, vascular invasion, multiple tumors, and positive surgical margin were significantly associated with overall death. On multivariate analysis, the independent prognostic factors identified were CRP/Alb ratio >0.089 (p < 0.001), lymph node metastasis (p = 0.01), and multiple tumors (p = 0.005).

Conclusion:

Preoperative CRP/Alb ratio may predict poor long-term outcomes after hepatic resection in patients with ICC.

Evaluation of apoptosis indexes in currently used oral alpha-blockers in prostate: a pilot study

Objectives:

Apoptosis effect of oral alpha-blockers is known in the prostate. Apoptosis index of silodosin has not been proved, yet. Aims are to present apoptosis index of silodosin in prostate and to compare this with other currently used alpha-blocker's apoptosis indexes together with their clinical effects.

Materials and Methods:

Benign prostatic hyperplasia (BPH) patients were enrolled among those admitted to urology outpatient clinic between June 2014 and June 2015. Study groups were created according to randomly prescribed oral alpha-blocker drugs as silodosin 8mg (Group 1; n=24), tamsulosin 0.4mg (Group 2; n=30), alfuzosin 10mg (Group 3; n=25), doxazosin 8mg (Group 4; n=22), terazosin 5mg (Group 5; n=15). Pa- tients who refused to use any alpha-blocker drug were included into Group 6 as control group (n=16). We investigated apoptosis indexes of the drugs in prostatic tissues that were taken from patient's surgery (transurethral resection of prostate) and/or prostate biopsies. Immunochemical dyeing, light microscope, and Image Processing and Analy- sis in Java were used for evaluations. Statistical significant p was p<0.05.

Results:

There were 132 patients with mean follow-up of 4.2±2.1 months. Pathologist researched randomly selected 10 areas in each microscope set. Group 1 showed statisti- cal significant difference apoptosis index in immunochemical TUNEL dyeing and im- age software (p<0.001). Moreover, we determined superior significant development in parameters as uroflowmetry, quality of life scores, and international prostate symptom score in Group 1.

Conclusions:

Silodosin has higher apoptosis effect than other alpha-blockers in prostate. Thus, clinic improvement with silodosin was proved by histologic studies. Besides, static factor of BPH may be overcome with creating apoptosis.

Silodosin for the treatment of clinical benign prostatic hyperplasia: safety, efficacy, and patient acceptability

α1-Adrenergic receptor antagonists are commonly used to treat male lower urinary tract symptoms and benign prostatic hyperplasia (BPH). We performed a literature search using PubMed, Medline via Ovid, Embase, and the Cochrane Library databases to identify studies on the treatment of BPH by silodosin. Silodosin is a novel α1-adrenergic receptor antagonist whose affinity for the α1A-adrenergic receptor is greater than that for the α1B-adrenergic receptor. Therefore, silodosin does not increase the incidence of blood pressure-related side effects, which may result from the inhibition of the α1B-adrenergic receptor. Patients receiving silodosin at a daily dose of 8 mg showed a significant improvement in the International Prostate Symptom Score and maximum urinary flow rate compared with those receiving a placebo. Silodosin also improved both storage and voiding symptoms, indicating that silodosin is effective, even during early phases of BPH treatment. Follow-up extension studies performed in the United States, Europe, and Asia demonstrated its long-term safety and efficacy. In the European study, silodosin significantly reduced nocturia compared to the placebo. Although retrograde or abnormal ejaculation was the most commonly reported symptom in these studies, only a few patients discontinued treatment. The incidence of adverse cardiovascular events was also very low. Evidence showing solid efficacy and cardiovascular safety profiles of silodosin will provide a good solution for the treatment of lower urinary tract symptoms associated with BPH in an increasingly aging society.

[Evolution of lower urinary tract symptoms under silodosin: factors influencing patients' satisfaction]

The objective of this study was to analyze the efficacy and safety of silodosin in patients with lower urinary tract symptoms (LUTS) associated with benign prostatic hyperplasia (BPH) in current urologic practice.

METHOD

This was a prospective observational study conducted by 272 urologists on patients treated by silodosin for BPH. The parameters evaluated were the weighted IPSS score, the IPSS question 8 related to quality of life, the USP score and the Athens Insomnia Scale (AIS) measured at treatment initiation and after 3 months.

RESULTS

Nine hundred and fourteen patients whose average age was 66 years with LUTS for 3.3 years were analyzed. After 3 months of treatment, a significant decrease in IPSS (from 16.2 ± 6.1 to 9.7 ± 5.5, P<0.0001) and USP score (from 10.6 ± 5.1 to 6 0 ± 4.6, P<0.0001) were observed, quality of life (from 67.1% to 14.4% of unsatisfied patients, P<0.0001) and sleep were significantly improved (from 49.2% to 28.9% patients with insomnia, P<0.0001). Among the patients, 21.2% experienced at least one adverse event. The most frequent were abnormal ejaculation (17.2%). And 7.1% discontinued the treatment for this reason. After 3 months of treatment silodosin was continued in 86.9% of patients.

CONCLUSION

This large study confirmed the efficacy of silodosin in LUTS associated with BPH with a safety profile that does not affect patient satisfaction.

Effects of silodosin, a selective α1A-adrenoceptor antagonist, on bladder blood flow and bladder function in a rat model of atherosclerosis induced chronic bladder ischemia without bladder outlet obstruction

PURPOSE

We investigated the effects of the selective α1A-adrenoceptor antagonist silodosin on bladder blood flow and bladder function in a rat model of atherosclerosis induced chronic bladder ischemia without bladder outlet obstruction.

MATERIALS AND METHODS

The chronic bladder ischemia model was prepared by creating balloon endothelial injury of the bilateral iliac arteries in male rats. Using an osmotic pump, chronic bladder ischemia rats received silodosin subcutaneously at a rate of 0.1 or 0.3 mg/kg per day, or vehicle for 8 weeks. All groups received a 2% cholesterol diet throughout the experiment. For each α1-adrenoceptor subtype mRNA expression in bladder microvessels was examined by in situ hybridization. Bladder blood flow was measured using a laser speckle blood flow imager. Malondialdehyde in bladder tissue and 8-hydroxy-2'-deoxyguanosine in urine were measured as markers of oxidative stress. A metabolic cage study and cystometry were performed in conscious rats.

RESULTS

The expression of all α1-adrenoceptor subtype mRNA was observed in rat bladder microvessels. Silodosin abrogated the decreased bladder blood flow in the empty bladder and during bladder distention that were evident in rats with chronic bladder ischemia. Levels of oxidative stress markers in these rats were significantly decreased by silodosin administration. Silodosin ameliorated bladder dysfunction in rats with chronic bladder ischemia in the metabolic cage study and on cystometry.

CONCLUSIONS

Results suggest that in ischemic conditions α1-adrenoceptor antagonists such as silodosin may improve bladder function by restoring bladder blood flow.

Investigation of ejaculatory disorder by silodosin in the treatment of prostatic hyperplasia

BACKGROUND

To assess the ejaculatory disorder caused by silodosin in the prostatic hyperplasia patients who carry out sexual actions (sexual intercourse, masturbation).

METHOD

The subjects of this study were 91 patients who had been clinically diagnosed to have LUTS/BPH at this hospital, who were administered silodosin at 4 mg twice a day, and who gave response to a questionnaire survey related to ejaculatory disorder. Sexual intercourse and masturbation were regarded as sexual actions in this study.

RESULTS

Ejaculatory disorder occurred in 38 (42%) of the 91 silodosin administration cases. Forty (44%) of the 91 patients answered that they carried out sexual actions after oral intake of silodosin. When the investigation was conducted only in those who exercised sexual actions, ejaculatory disorder was observed in 38 (95%) of these 40 patients, indicating a high incidence. When asked if disturbed by the ejaculatory disorder, 29 (76%) of the 38 patients who had ejaculatory disorder answered yes. Oral silodosin was discontinued due to the ejaculatory disorder in 2 (5%) of these patients. On the whole, the discontinuation rate of oral silodosin was 2% (2/91 patients).

CONCLUSION

It was demonstrated that the administration of silodosin induced ejaculatory disorder at a high incidence. Since it is possible that the high frequency of ejaculatory disorder by silodosin may reduce QOL, it is considered necessary to provide sufficient information related to ejaculatory disorder at the time of treatment with silodosin.