The use of 5-alpha reductase inhibitors in the treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia(BPH)is characterized by an enlarged prostate,lower urinary tract symptoms(LUTS),and a decreased urinary flow rate.Common in older men,BPH is a progressive disease that can eventually lead to complications including acute urinary retention(AUR)and the need for BPH-related surgery.Both normal and abnormal prostate growth is driven by the androgen dihydrotestosterone(DHT),which is formed from testosterone under the influence of 5-alpha reductase.Thus,5-alpha reductase inhibitors(5-ARIs)effectively reduce the serum and intraprostatic concentration of DHT,causing an involution of prostate tissue.Two 5-ARIs are currently available for the treatment of BPHdfinasteride and dutasteride.Both have been demonstrated to decrease prostate volume,improve LUTS and urinary flow rates,which ultimately reduces the risk of AUR and BPH-related surgery.Therefore,either alone or in combination with other BPH medications,5-ARIs are a mainstay of BPH management.

Medical therapy for clinical benign prostatic hyperplasia:α1 Antagonists,5α reductase inhibitors and their combination

Medical therapy for clinical benign prostatic hyperplasia(BPH)has advanced significantly in the last 2 decades.Many new a1 antagonists and 5a reductase inhibitors(5ARi)are now commercially available.The practicing urologist must decide on the most appropriate medication for his patients,taking into consideration various factors like efficacy,dosing regime,adverse effects,cost,patient’s socioeconomic background,expectations,drug availability and his own clinical experience.The use of combination therapy added further to the complexity in clinical judgment when prescribing.We highlight some of the key points in prescribing a1 antagonists,5ARi and their combination,based on our viewpoints and experience as urologists in an Asian clinical setting.

A systematic review of the effects and mechanisms of preoperative 5α-reductase inhibitors on intraoperative haemorrhage during surgery for benign prostatic hyperplasia

5α-reductase inhibitors （5α-RIs）, including finasteride and dutasteride, are commonly used medical therapies for benign prostatic hyperplasia （BPH）. Many studies reported that preoperative 5α-RI had impact on intraoperative haemorrhage during surgery for BPH, but it was still in controversial. So, we conducted a systematic review of the effects and mechanisms of 5α-RIs on intraoperative bleeding for BPH. MEDLINE, EMBASE, the Cochrane Controlled Trail Register of Controlled Trials and the reference lists of retrieved studies were searched in the analysis. Sixteen publications involving 15 different randomized controlled trials （RCTs） and a total of 1156 patients were used in the analysis, including 10 RCTs for finasteride and five RCTs for dutasteride. We found that preoperative finasteride treatment decreases microvessel density （MVD） in resected prostate specimens. Total blood loss, blood loss per gram of resected prostate tissue and decreases in haemoglobin were all greatly reduced in the finasteride group as compared to controls. Dutasteride appeared to have no effect on bleeding. This meta-analysis shows that preoperative finasteride treatment could decrease intraoperative haemorrhage during surgery for BPH. Preoperative dutasteride had no effect on intraoperative haemorrhage, but further high-qualitv prospective studies are still needed to confirm this observation.

Screening of traditional Chinese medicine monomers as ribonucleotide reductase M2 inhibitors for tumor treatment

BACKGROUND Ribonucleotide reductase(RR)is a key enzyme in tumor proliferation,especially its subunit-RRM2.Although there are multiple therapeutics for tumors,they all have certain limitations.Given their advantages,traditional Chinese medicine(TCM)monomers have become an important source of anti-tumor drugs.Therefore,screening and analysis of TCM monomers with RRM2 inhibition can provide a reference for further anti-tumor drug development.AIM To screen and analyze potential anti-tumor TCM monomers with a good binding capacity to RRM2.METHODS The Gene Expression Profiling Interactive Analysis database was used to analyze the level of RRM2 gene expression in normal and tumor tissues as well as RRM2's effect on the overall survival rate of tumor patients.TCM monomers that potentially act on RRM2 were screened via literature mining.Using AutoDock software,the screened monomers were docked with the RRM2 protein.RESULTS The expression of RRM2 mRNA in multiple tumor tissues was significantly higher than that in normal tissues,and it was negatively correlated with the overall survival rate of patients with the majority of tumor types.Through literature mining,we discovered that berberine,ursolic acid,gambogic acid,cinobufagin,quercetin,daphnetin,and osalmide have inhibitory effects on RRM2.The results of molecular docking identified that the above TCM monomers have a strong binding capacity with RRM2 protein,which mainly interacted through hydrogen bonds and hydrophobic force.The main binding sites were Arg330,Tyr323,Ser263,and Met350.CONCLUSION RRM2 is an important tumor therapeutic target.The TCM monomers screened have a good binding capacity with the RRM2 protein.

Aspects of Antithrombotic Effect of HMG-CoA Reductase Inhibitors

Statins, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors are widely used for the treatment of hypercholesteremia and have showed remarkable activity in preventing cardiovascular morbidity and mortality. Recent studies demonstrated that statins have significant antithrombotic effect in addition to cholesterollowering action. Although the efficacy of statins for reducing cardiovascular events has historically been ascribed to their inhibitory activity on cholesterol synthesis, the degree of low-density lipoprotein cholesterol reduction by statins generally does not correlate with the magnitude of coronary risk reduction.

Pre-Androgen Ablation Prostate Cancer Patients Who Bleed Do Well with 5 Alpha Reductase Inhibitors

Background: Patients with gross haematuria are sometimes found to have prostate cancer after clinical evaluation. The treatment of such haematuria could be very challenging. Use of a 5 alpha reductase inhibitor like dutasteride has been found helpful in bleeding prostate cancer patients if they have not undergone hormonal manipulation before they developed haematuria. Patients and Method: 26 patients with gross haematuria of prostatic origin who had histologic confirmation of adenocarcinoma of the prostate but who have not had chemical or surgical castration were randomized to receive daily dutasteride in addition to vigorous saline irrigation and antibiotics on one arm and vigorous saline irrigation and antibiotics only as control on the other arm. The time taken before haematuria resolved and the amount of irrigation fluid used were noted. Statistical analysis was done using SPSS. Student’s t-test and Kaplan Meier survival analysis were used to test various variables at 0.5 significant levels. Results: Of the 26 patients 12(46.2%) received 0.5 mg oral dutasteride in addition to saline irrigation while 14 (53.8%) received saline irrigation only. Haematuria stopped in all of 12 (100%) patients on dutasteride arm but on 12 (85.7%) of the 14 patients on the control arm. It took significantly shorter time and lesser volume of irrigation fluid before haematuria resolved in those treated with dutasteride than in those on the control arm. Conclusion: Dutasteride is effective in the control of acute haematuria in pre-androgen ablation prostate cancer patients.

Relation between Baseline Lipid Levels and Effectiveness of HMG-CoA Reductase Inhibitors in Patients with Hyperlipidemia

Objective To evaluate whether the effects of HMG - CoA reductase inhibitors on patients with hyperlipidemia are closely related to baseline lipid levels. Methods The data analyzed originated from 3 separate multicenter clinical trials with similar designs during 1994 to 1999. 166 patients with mean age 58. 9±9. 2 years were involved in Simvastatin Clinical Trial with simvastatin 10 mg once daily for 8 weeks. 146 patients with mean age 57. 9±8. 7years were involved in Lovastatin Clinical Trial with lovastatin 20 mg once daily for 8 weeks. 105 patients with mean age 57. 8±9. 3 years were involved in Atorvastatin Clinical Trial with atorvastatin 10 mg once daily for 6 weeks. Baseline total cholesterol (TC) was more than 5. 98 mmol. L - 1, and baseline triglyceride (TG) was less than 4. 52 mmo. L - 1. The patients were grouped by baseline lipid levels. Results The higher the baseline TC, low density lipoprotein cholesterol (LDL - C) and TG levels were, the more effective the simvastatin, lovastatin, or atorvastatin was in reducing serum TC, LDL - C, and TG, respectively. A positive linear correlation was found between baseline values and effects of simvastatin, lovastatin, or atorvastatin in reducing serum TC, LDL - C, and TG, respectively. Conclusion The changes of reduction on serum lipid with HMG - CoA reductase inhibitors in patients with hyperlipidemia were influenced by baseline lipid levels.

Changes in aortic endothelium ultrastructure in male rats following castration, replacement with testosterone and administration of 50α-reductase inhibitor

Aim： To investigate the relationship between low androgen level and ultrastructure of vascular endothelium. Methods： Forty-eight male Sprague-Dawley rats were randomly divided into four groups： group A, normal rats with sham castration; group B, castrated rats; group C, castrated rats given testosterone （T） undecanoate; and group D, intact rats treated with 5α-reductase inhibitor. After 10 weeks of treatment or castration, rats in different groups were killed and serum T, free T （FT） and dihydrotestosterone （DHT） were measured. The aortic endothelia were scanned under electron microcopy and the Vascular Endothelium Structure Score （VESS） was computed. Results： Serum T and FT concentrations of rats in group B were significantly lower than those of the other three groups （P 〈 0.01）; DHT concentrations of group D rats were significantly decreased （P 〈 0.01 ） when compared with those of groups A and C. Rats in groups B and D rats （with low androgen levels） had obvious damage to their endothelial surfaces, which appeared crimpled, rough, adhesive and ruptured, and had high destruction of VESS. Conclusion： These results suggest that low concentrations of T and DHT are associated with ultrastructural damage of the aortic endothelia in male rats.

A novel thioredoxin reductase inhibitor inhibits cell growth and induces apoptosis in HL-60 and K562 cells

Human thioredoxin reductase (TrxR) system is associated with cancer cell growth and anti-apoptosis process. Effects of 1,2-bis(1,2-benzisoselenazolone-3(2H)-ketone)ethane (BBSKE),a novel TrxR inhibitor,were investigated on human leu-kemia cell lines HL-60 and K562. BBSKE treatment induced cell growth inhibition and apoptosis in both cell lines. Apoptosis induced by BBSKE is through Bcl-2/Bax and caspase-3 pathways. Ehrlich's ascites carcinoma-bearing mice were used to inves-tigate the anti-tumor effect of BBSKE in vivo. Tumor-bearing mice treated with BBSKE showed an increase of life span with a comparable effect to cyclophosphamide (CTX). These results suggest a potential usage of BBSKE as a therapeutic agent against non-solid tumors.

High-throughput fluorescent screening of thioredoxin reductase inhibitors to inhibit Mycobacterium tuberculosis

Tuberculosis(TB)is a chronic infectious disease,which is caused by the pathogen Mycobacterium tuberculosis(Mtb)and reemerged as a global health risk with a significant proportion of multi-drug resistant and extensively drug resistant TB cases.It is very urgent to find some novel high-confidence drug targets in Mtb for discovering the effective anti-TB agents.Thioredoxin reductase(TrxR)has been identified to be a highly viable target for anti-TB drugs for its important role in protecting the pathogen from thiol-specific oxidizing stress,regulating intracellular dithiol/disulfide homeostasis and DNA replication and repair.In the present work,a near-infrared(NIR)fluorescent probe DDAT was developed for the detection of TrxR activity and used to high-throughput screen the TrxR inhibitors from natural products.Two screened TrxR inhibitors from Sappan Lignum and microbial metabolites that were further used to inhibit Mycobacterium tuberculosis.All the results indicate that DDAT is a practical fluorescent molecular tool for the discovery of potential anti-TB drugs.

Nrf2-inducing and HMG-CoA reductase inhibitory activities of a polyphenol-rich fraction of Guazuma ulmifolia leaves

Objective: To fractionate and identify polyphenols from Guazuma ulmifolia Lam. leaves, and to explore their antioxidant, 5-hydroxy-3-methylglutaryl-coenzyme A(HMG-Co A) reductase inhibitory, and Nrf2 modulatory activities.Methods: The 1,1-diphenyl-2-picrylhydrazyl assay was used to evaluate the antioxidant activity of a polyphenolic fraction of the extract of Guazuma ulmifolia Lam. leaves. THP-1 gene reporter cell lines constructed with a transcriptional response element specific for Nrf2 and a minimal promoter for the firefly luciferase–green fluorescent protein transgene were used to determine the effect of the polyphenolic fraction on the Nrf2 signaling pathway. Furthermore, an assay of HMG-Co A reductase inhibitory activity was performed by using a commercial enzyme kit. Polyphenolic compounds were identified by liquid chromatographytandem mass spectrometry.Results: The polyphenolic fraction showed fairly strong antioxidant activity [IC50 =(14.90 ± 4.70) μg/m L] and inhibited HMG-Co A reductase activity by 69.10%, which was slightly lower than that by pravastatin(84.37%) and quercetin(84.25%). Additionally, the polyphenolic fraction activated the Nrf2 antioxidant signaling pathway at 500 μg/m L. Eleven subfractions resulting from the column chromatography separation of the polyphenolic fraction also showed relatively strong antioxidant activities(IC50: 17.46–217.14 μg/m L). The subfraction(F6) stimulated the Nrf2 signaling pathway and had HMG-Co A reductase inhibitory activity(65.43%). Moreover, the subfraction contained two main flavonoids: quercetin and quercimeritrin.Conclusions: The polyphenolic fraction of Guazuma ulmifolia could induce antioxidant genes via the Nrf2/antioxidant regulatory elements pathway, and is a promising candidate for an inhibitor of HMG-Co A reductase.

Search of inhibitors of aldose reductase for treatment of diabetic cataracts using machine learning

Purpose:Patients with diabetes mellitus have an elevated chance of developing cataracts,a degenerative visionimpairing condition often needing surgery.The process of the reduction of glucose to sorbitol in the lens of the human eye that causes cataracts is managed by the Aldose Reductase Enzyme(AR),and it is been found that AR inhibitors may mitigate the onset of diabetic cataracts.There exists a large pool of natural and synthetic AR inhibitors that can prevent diabetic complications,and the development of a machine-learning(ML)prediction model may bring new AR inhibitors with better characteristics into clinical use.Methods:Using known AR inhibitors and their chemical-physical descriptors we created the ML model for prediction of new AR inhibitors.The predicted inhibitors were tested by computational docking to the binding site of AR.Results:Using cross-validation in order to find the most accurate ML model,we ended with final cross-validation accuracy of 90%.Computational docking testing of the predicted inhibitors gave a high level of correlation between the ML prediction score and binding free energy.Conclusions:Currently known AR inhibitors are not used yet for patients for several reasons.We think that new predicted AR inhibitors have the potential to possess more favorable characteristics to be successfully implemented after clinical testing.Exploring new inhibitors can improve patient well-being and lower surgical complications all while decreasing long-term medical expenses.

新型醛糖还原酶抑制1-乙酰基-1H-吲哚-3-乙酸酯的合成及其抑制活性

醛糖还原酶抑制剂(ARIs)抑制多元醇途径的醛糖还原酶是治疗糖尿病并发症的重要策略。以2-氯苯甲酸为起始原料,在碱性条件下经铜催化,与甘氨酸反应生成氯代邻羧基苯基甘氨酸,再与乙酸酐反应,生成N-乙酰基邻羧基苯甲酸。然后在吡啶催化下合环,生成1-乙酰基-^(1)H-吲哚-3-乙酸酯(AIA),总收率为79.0%,纯度为99.0%。通过^(1)H NMR、^(13)C NMR和MS(ESI)对其结构进行表征,并对该化合物的的醛糖还原酶抑制活性进行测定,IC 50=9.4×10^(-2)μM。

硫氧还蛋白还原酶结构与肿瘤治疗的研究进展

硫氧还蛋白还原酶(thioredoxin reductase,TrxR)是硫氧还蛋白(thioredoxin,Trx)系统里主要的功能蛋白,在调节多种细胞氧化还原信号通路中起关键作用。近年来,TrxR/Trx被越来越多地认为是肿瘤发展的重要调节剂,因此靶向TrxR/Trx是一种很有前景的肿瘤治疗策略。该文对TrxR的结构特点、与肿瘤相关的生理功能、TrxR抑制剂进行综述,以对TrxR的研究提供参考。

预防对比剂相关性急性肾损伤的研究进展

对比剂相关性急性肾损伤(CA-AKI)是在诊断或介入手术中使用对比剂所引起的一种严重并发症,目前已成为住院患者新发急性肾功能不全的主要原因之一。选择相对低毒的对比剂,减少对比剂暴露的时间和剂量对CA-AKI有一定的预防作用,他汀等药物以及术前术后的水化能够降低CA-AKI的风险,目前纳米药物已被证明在动物模型中获益。该文就当前CA-AKI的防治进行综述,为进一步深入研究新的干预措施奠定基础,并为临床治疗提供理论依据。

他汀类药物在缺血性脑血管病二级预防中的应用效果及其影响因素

【目的】探讨他汀类药物在缺血性脑血管病(ICVD)二级预防中的应用效果及其影响因素。【方法】本院收治的109例ICVD患者,随访1年,死亡1例,失访2例,根据是否再次发生ICVD将患者分为复发组和未复发组,比较两组患者的临床资料,探讨影响他汀类药物预防效果的因素。【结果】纳入的106例患者,其中15例(14.15%)ICVD复发,未复发91例(85.85%)。复发组和未复发组的年龄、性别、家族史、吸烟史、饮酒史、白细胞计数、血糖比较,差异均无统计学意义(P>0.05);两组体重指数(BMI)、文化程度、医疗支付方式、合并疾病数量、服用药物种类以及依从性等比较,差异有统计学意义(P<0.05)。多因素回归分析显示,BMI高、文化程度低、自费医疗支付、合并疾病数量多、服用药物种类多以及依从性低是他汀类药物在ICVD二级预防中复发的独立危险因素(P<0.05)。【结论】他汀类药物在ICVD二级预防中的效果受患者BMI、文化程度、医疗支付方式、合并疾病数量、药物种类及依从性等因素影响,优化二级预防需关注上述因素。

High-throughput screening against thioredoxin glutathione reductase identifies novel inhibitors with potential therapeutic value for schistosomiasis

Background:Schistosomiasis,a parasitic disease also known as bilharzia and snail fever,is caused by different species of flatworms,such as Schistosoma mansoni(S.mansoni).Thioredoxin glutathione reductase(TGR)from S.mansoni(SmTGR)is a well-characterized drug target for schistosomiasis,yet no anti-SmTGR compounds have reached clinical trials,suggesting that therapeutic development against schistosomiasis might benefit from additional scaffolds targeting this enzyme.Methods:A high-throughput screening(HTS)assay in vitro against SmTGR was developed and applied to a diverse compound library.SmTGR activity was quantified with ThioGlo®,a reagent that fluoresces upon binding to the free sulfhydryl groups of the reaction product GSH(reduced glutathione).Results:We implemented an HTS effort against 59,360 synthetic compounds.In the primary screening,initial hits(928 or 1.56%)showing greater than 90%inhibition on SmTGR activity at a final concentration of 10μM for each compound were identified.Further tests were carried out to confirm the effects of these hits and to explore the concentration-dependent response characteristics.As a result,74 of them(0.12%)representing 17 chemical scaffolds were confirmed and showed a great concentration-dependent inhibitory trend against SmTGR,including structures previously shown to be lethal to schistosomal growth.Of these,two scaffolds displayed a limited structure-activity relationship.When tested in cultured larvae,39 compounds had cidal activity in 48 h,and five of them killed larvae completely at 3.125μM.Of these,three compounds also killed adult worms ex vivo at concentrations between 5μM and 10μM.Conclusion:These confirmed hits may serve as starting points for the development of novel therapeutics to combat schistosomiasis.

Inhibitory effect of fluvastatin on ileal ulcer formation in rats induced by nonsteroidal antiinflammatory drug

AIM: Nonsteroidal anti-inflammatory drugs (NSAIDs)cause gastrointestinal damage as one of their side effects in humans and experimental animals. Lipid peroxidation plays an important role in NSAID-induced ulceration. The aim of this study was to investigate the inhibitory effect of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA)reductase inhibitors on the ulceration in small intestines of rats.METHODS: The effects of three HMG-CoA reductase inhibitors, fluvastatin, pravastatin and atorvastatin on ileal ulcer formation in 5-bromo-2-(4-fluorophenyl)-3-(4-methylsulfonylphenyl) thiophene (BFMeT)-treated rats were examined. Antioxidative activity of the inhibitors was measured by a redox-linked colorimetric method.RESULTS: Fluvastatin, which was reported to have antioxidative activity, repressed the ileal ulcer formation in rats treated with BFMeT an NSAIDs. However, the other HMG-CoA reductase inhibitors (pravastatin and atorvastatin)did not repress the ileal ulcer formation. Among these HMG-CoA reductase inhibitors, fluvastatin showed a significantly stronger reducing power than the others(pravastatin, atorvastatin).CONCLUSION: Fluvastatin having the antioxidaitive activity suppresses ulcer formation in rats induced by NSAIDs.

INHIBITORY EFFECT OF FLUVASTATIN ON AORTIC INTIMAL THICKENING IN NORMOCHOLESTEROLEMIC RABBITS

The anti atherosclerotic effect of fluvastatin at doses insufficient to lower serum cholesterol on the catheter induced intimal thickening and possible mechanism were investigated in abdominal aorta of rabbits. Methods.Fifty six rabbits were randomly divided into eight groups(n=7,each).Fluvastatin was given mixed with food at daily dose of8mg/kg starting 5 days before catheterization.Light microscope,immunohistochemistry,transmission electron microscope and RT PCR assay were applied to assess vascular smooth muscle cell (VSMC)proliferation and apoptosis, as well as oncogene expression in vascular wall. Results.At day 10 and day 15 after catheter induced denudation intima/media(I/M)thickness ratio was obviously higher, and also the percentage of PCNA positive cells and TUNEL positive cells in media was significantly higher compared with controls.The intimal hyperplasia was mostly composed of α SM actin positive cells.In rabbits given fluvastatin I/M ratio and the percentage of these positive cells significantly decreased compared with those without fluvastatin.The overexpression of proto oncogene H ras mRNA and decreased expression of anti oncogene p53 mRNA were found after vascular injury,whereas fluvastatin significantly reduced H ras mRNA and increased p53 mRNA expression. Conclusion.Proliferation of VSMC in the media and the migration to the intima can be inhibited,and apoptosis of VSMC be induced by short term use of fluvastatin after balloon catheter denudation,independent of serum lipid change.The underlying mechanism is presumably associated with the influence of fluvastatin on oncogene expression in the injured vascular wall.

Effects of competitive and noncompetitive 5α-reductase inhibitors on serum and intra-prostatic androgens in beagle dogs

Background 5a-Reductase inhibitors （5a-RI） act by inhibiting the conversion of testosterone to dihydrotestosterone （DHT）, thereby preventing DHT induced benign prostatic hyperplasia. The existing 5a-RIs can be classified into two types： competitive and noncompetitive. Currently, limited evidence is available concerning the effect differences between the two types of 5a-RI on androgens. The purpose of this study was to assess the effects of competitive and noncompetitive 5a-RIs on serum and intra-prostatic androgens in beagle dogs. Methods Twenty beagles with spontaneous benign prostatic hyperplasia were randomly allocated into two groups： epristeride group （n=10） in which beagles were treated with epristeride at 1 mg/kg once a day for 3 months, and finasteride group （n=10） in which beagles were treated with finasteride at 1 mg/kg once a day for 3 months. The levels of intra-prostatic testosterone and DHT were measured before treatment and on day one after three months medication. Serum levels of testosterone and DHT were measured at the same time points. Changes in androgen levels before and after treatment were analyzed, and comparisons were made within each treatment group and between treatment groups. Results After 3-month treatment, serum and intra-prostatic DHT levels all decreased significantly in both the epristeride and finasteride groups. The change of DHT in serum was significantly higher in the finasteride group （-14% and -43% in epdsteride and finasteride groups respectively, with P〈0.001）; however there was no significant difference in the changes of intra-prostatic DHT between the two groups （-47% and -51% in epristeride and finasteride groups, respectively, P=0.304）. The decreases in DHT levels were accompanied by reciprocal increases in serum and intra-prostatic testosterone levels. Changes of testosterone were significantly higher in finasteride group both in serum （20% and 42% in epristeride and finasteride groups, respectively, P〈0.001） and in prostate tissue （18% and 29% in epristeride and finasteride groups, respectively, P=0.004）. Conclusions Two types of 5a-RI have similar effects in reducing DHT in prostate tissue in beagles. Competitive 5a-RI may reduce serum DHT to a greater scale, and significantly increase testosterone in beagle serum and prostate.