Differences in Stroke Recurrence Risk Between Atrial Fibrillation Detected on ECG and 14-Day Cardiac Monitoring.

BACKGROUND: Ischemic stroke and transient ischemic attack (TIA) standard-of-care etiological investigations include an ECG and prolonged cardiac monitoring (PCM). Atrial fibrillation (AF) detected after stroke has been generally considered a single entity, regardless of how it is diagnosed. We hypothesized that ECG-detected AF is associated with a higher risk of stroke recurrence than AF detected on 14-day Holter (PCM-detected AF). METHODS: We conducted a retrospective, registry-based, cohort study of consecutive patients with ischemic stroke and TIA included in the London Ontario Stroke Registry between 2018 and 2020, with ECG-detected and PCM-detected AF lasting ≥30 seconds. We quantified PCM-detected AF burden. The primary outcome was recurrent ischemic stroke, ascertained by systematically reviewing all medical records until November 2022. We applied marginal cause-specific Cox proportional hazards models adjusted for qualifying event type (ischemic stroke versus TIA), CHA2DS2-VASc score, anticoagulation, left ventricular ejection fraction, left atrial size, and high-sensitivity troponin T to estimate adjusted hazard ratios for recurrent ischemic stroke. RESULTS: We included 366 patients with ischemic stroke and TIA with AF, 218 ECG-detected, and 148 PCM-detected. Median PCM duration was 12 (interquartile range, 8.8-14.0) days. Median PCM-detected AF duration was 5.2 (interquartile range, 0.3-33.0) hours, with a burden (total AF duration/total net monitoring duration) of 2.23% (interquartile range, 0.13%-12.25%). Anticoagulation rate at the end of follow-up or at the first event was 83.1%. After a median follow-up of 17 (interquartile range, 5-34) months, recurrent ischemic strokes occurred in 16 patients with ECG-detected AF (13 on anticoagulants) and 2 with PCM-detected AF (both on anticoagulants). Recurrent ischemic stroke rates for ECG-detected and PCM-detected AF groups were 4.05 and 0.72 per 100 patient-years (adjusted hazard ratio, 5.06 [95% CI, 1.13-22.7]; P=0.034). CONCLUSIONS: ECG-detected AF was associated with 5-fold higher adjusted recurrent ischemic stroke risk than PCM-detected AF in a cohort of ischemic stroke and TIA with >80% anticoagulation rate.

Sex Differences in Outcomes Following Left Atrial Appendage Closure.

OBJECTIVE: To evaluate the effects of female sex on in-hospital outcomes and to provide estimates for sex-specific prediction models of adverse outcomes following left atrial appendage closure (LAAC). PATIENTS AND METHODS: Cohort-based observational study querying the National Inpatient Sample database between October 1, 2015, and December 31, 2017. Demographics, baseline characteristics, and comorbidities were assessed with the Charlson Comorbidity Index (CCI), Elixhauser Comorbidity Index score (ECS), and CHA2DS2-VASc score. The primary outcome was in-hospital major adverse events (MAEs) defined as the composite of bleeding, vascular, cardiac complications, post-procedural stroke, and acute kidney injury. The associations of the CCI, ECS, and CHA2DS2-VASc score with in-hospital MAE were examined using logistic regression models for women and men, respectively. RESULTS: A total of 3294 hospitalizations were identified, of which 1313 (40%) involved women and 1981 (60%) involved men. Women were older (76.3±7.7 vs 75.2±8.4 years, P<.001), had a higher CHA2DS2-VASc score (4.9±1.4 vs 3.9±1.4, P<.001) but showed lower CCI and ECS compared with men (2.1±1.9 vs 2.3±1.9, P=.01; and 9.3±5.9 vs 9.9±5.7, P=.002, respectively). The primary composite outcome occurred in 4.6% of patients and was higher in women compared with men (women 5.6% vs men 4.0%, P=.04), and this was mainly driven by the occurrence of cardiac complications (2.4% vs 1.2%, P=.01). In women, older age, higher median income, and higher CCI (adjusted odds ratio [aOR], 1.32; 95% confidence interval [CI], 1.21 to 1.44; P<.001), ECS (aOR, 1.04; 95% CI, 1.02 to 1.07; P=.002), and CHA2DS2-VASc score (aOR, 1.24; 95% CI, 1.10 to 1.39; P<.001) were associated with increased risk of in-hospital MAE. In men, non-White race/ethnicity, lower median income, and higher ECS (aOR, 1.06; 95% CI, 1.04 to 1.09; P<.001) were associated with increased risk of in-hospital MAE. CONCLUSION: Women had higher rates of in-hospital adverse events following LAAC than men did. Women with older age and higher median income, CCI, ECS, and CHA2DS2-VASc scores were associated with in-hospital adverse events, whereas men with non-White race/ethnicity, lower median income, and higher ECS were more likely to experience adverse events. Further research is warranted to identify sex-specific, racial/ethnic, and socioeconomic pathways during the patient selection process to minimize complications in patients undergoing LAAC.

Dedicated Bifurcation Stents for Coronary Bifurcation Lesions: A Systematic Review and Meta-Analysis of Randomized-Controlled Trials.

BACKGROUND: Percutaneous coronary intervention (PCI) of coronary bifurcation lesions (CBL) remains a challenge in contemporary practice due to the procedural and technical difficulties involved. We sought to review the current evidence on the safety and clinical outcomes of dedicated bifurcation stent (DBS) implantation in comparison with established treatment strategies for CBL-PCI. METHODS: We conducted a comprehensive search to identify randomized control trials (RCTs) reporting 1-year clinical and angiographic outcomes of patients undergoing CBL-PCI with DBS vs conventional CBL-PCI strategies. Random-effects meta-analyses were performed to estimate the effect of DBS compared with conventional CBL-PCI using aggregate data. RESULTS: A total of 5 RCTs comprising 1249 participants met the inclusion criteria. The use of DBS was comparable to conventional stenting techniques in terms of major adverse cardiovascular event (MACE) rate (odds ratio [OR], 1.28; 95% confidence interval [CI], 0.90- 1.82; I²=0%), all-cause mortality (OR, 0.80; 95% CI, 0.31-2.07; I²=0%), cardiac mortality (OR, 0.16; 95% CI, 0.02-1.39; I²=0%), myocardial infarction (OR, 1.26; 95% CI, 0.84-1.89; I²=0%), definite stent thrombosis (OR, 1.75; 95% CI, 0.36-8.52; I²=0%), cumulative target-lesion revascularization (OR, 1.39; 95% CI, 0.85-2.27; I²=0%), clinically driven target-lesion revascularization (OR, 1.23; 95% CI, 0.68-2.22; I²=0%), or target-vessel revascularization (OR, 1.43; 95% CI, 0.92-2.22; I²=0%). CONCLUSION: The present analysis suggests that CBL-PCI with DBS may be associated with similar 1-year clinical and angiographic outcomes compared with conventional CBL-PCI strategies. However, the low quality of evidence and limited follow-up warrant further studies to ascertain any significant differences in patient-important outcomes before the adoption of DBS into routine CBL-PCI practice.

Antisulfatase, Osteogenic, and Anticancer Activities of Steroid Sulfatase Inhibitor EO-33 in Mice.

Steroid sulfatase (STS) is a key enzyme involved in the biosynthesis of estrogens from inactive sulfated steroids. After we reported EO-33 as a potent in vitro STS inhibitor without undesirable estrogenic activity and with osteogenic properties, we are now interested in validating EO-33's in vivo potential to inhibit STS, to prevent bone deterioration, and to reduce estrogen-dependent tumor growth. A scale-up synthesis was first elaborated to prepare the multigram quantity of EO-33 needed to perform in vivo studies. EO-33 blocked the uterine weight stimulated by estrone sulfate in ovariectomized mice by 69% and the STS activity in the liver by 81%. It also produced a selective estrogen receptor modulator effect as assessed by measuring the tibia weight and calcium content. Using a human breast cancer (MCF-7 xenograft) model in nude mice, EO-33 blocked 90% of tumor growth induced by estradiol sulfate, and no toxic effect was observed by assessing the body and liver weights.

Radial versus femoral approach for saphenous vein grafts angiography and interventions.

BACKGROUND: Coronary angiography and intervention to saphenous venous grafts (SVGs) remain challenging. This study aimed to investigate the feasibility and safety of the radial approach compared to femoral access in a large cohort of patients undergoing SVG angiography and intervention. METHODS: Data from 1,481 patients from Canada, United States, and Spain who underwent procedures between 2010 and 2016 were collected. Patients must have undergone SVG coronary angiography and/or intervention. Demographics, procedural data, and in-hospital complications were recorded. RESULTS: Procedures were undertaken by either the radial (n = 863, 211 intervention) or femoral (n = 618, 260 intervention) approach. The mean number of SVGs per patient was similar between groups (radial 2.3 ± 0.7 vs femoral 2.6 ± 1.1, P = .61), but the radial group required a fewer number of catheters (2.6 ± 1.7 vs 4.1 ± 1.1, P < .001). Fluoroscopy time was comparable between groups, and there was a trend toward lower contrast volume in the radial group (P = .045). Overall, the total dose of heparin was significantly higher in the radial group (P < .001); however, radial patients experienced significantly less access-site bleeding complications (P < .001). Outpatients undergoing radial SVG interventions had a higher likelihood of a same-day discharge home (P < .001). CONCLUSIONS: Radial access for SVG angiography and intervention is safe and feasible, without increasing fluoroscopy time. In experienced centers, radial access was associated with fewer catheters used, lower contrast volume, and lower rate of vascular access-site bleeding complications. Moreover, outpatients undergoing SVG percutaneous coronary intervention though the radial approach had a higher likelihood of a same-day discharge home.

Pre-operative use of aspirin in patients undergoing coronary artery bypass grafting: a systematic review and updated meta-analysis.

Background: Aspirin therapy improves saphenous vein graft (SVG) patency in patients undergoing coronary artery bypass graft (CABG), however, its use in the pre-operative period remains controversial. Therefore, we conducted a systematic review and meta-analysis of randomized-controlled trials (RCTs) to update the evidence about risk and benefits of pre-operative aspirin therapy in patients undergoing CABG. Methods: Electronic databases (Medline, Embase, PubMed, Cochrane Library, and Scopus) were searched to identify RCTs evaluating the effect of aspirin versus placebo/control before CABG. Two investigators independently and in duplicate screened citations and extracted data and rated the risk of bias. The strength of evidence was appraised using the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) approach. Meta-analysis was performed using a random-effects model. The main outcomes of interest were 30-day mortality, peri-operative myocardial infarction (MI), chest tube drainage and SVG occlusion. Results: A total of 13 RCTs involving 4,377 participants (2,266/2,111 pre-operative aspirin/control) met the inclusion criteria. Pre-operative aspirin reduced the risk of SVG occlusion [risk ratio (RR): 0.69, 95% confidence interval (CI): 0.49-0.97, P=0.03, I2=16%], but no differences in mortality (RR: 1.41, 95% Cl: 0.73-2.74, I2=0%) and MI (RR: 0.84, 95% CI: 0.69-1.03, I2=0%) were found. However, pre-operative aspirin increased chest tube drainage (MD: 100.40 mL, 95% CI: 24.32-176.47 mL, P=0.01, I2=84%) and surgical re-exploration (RR: 1.52, 95% CI: 1.02-2.27, P=0.04, I2=8%), with no significant difference in RBC transfusion (RR: 1.06, 95% CI: 0.90-1.25, I2=35%). Conclusions: Based on trials where the rated body of evidence was of low to very-low quality, pre-operative aspirin improves SVG patency but increases chest tube drainage and need for surgical re-exploration.

Pharmacokinetic profile of PBRM in rodents, a first selective covalent inhibitor of 17ß-HSD1 for breast cancer and endometriosis treatments.

The development of a covalent inhibitor of 17ß-hydroxysteroid dehydrogenase type 1 (17ß-HSD1) is a promising approach for the treatment of hormone-dependent breast cancer and endometriosis. After reporting the steroid derivative PBRM as a first potent covalent inhibitor of 17ß-HSD1 without estrogenic activity, we are now interested in studying its pharmaceutical behavior. The metabolism study in a human liver microsomal preparation showed a gradual transformation of PBRM into PBRM-O, an oxidized ketonic form of PBRM at position C17. Interestingly, PBRM-O also inhibits 17ß-HSD1 and is not estrogenic in estrogen-sensitive T-47D cells. However, when PBRM was injected subcutaneously (sc) in mice, a very small proportion of PBRM-O was measured in a 24 h-time course experiment. A pharmacokinetic study in mice revealed suitable values for half-life (T1/2 = 3.4 h), clearance (CL = 2088 mL/h kg), distribution volume (Vz = 10.3 L/kg) and absolute bioavailability (F = 65%) when PBRM was injected sc at 14.7 mg/kg. A good F value of 33% was also obtained when PBRM was given orally. A tritiated version of PBRM, 3H-PBRM, was synthesized and used for an in vivo biodistribution study that showed its gradual accumulation in various mouse tissues (peak at 6 h) followed by elimination until complete disappearance after 72 h. Elimination was found to occur in feces (93%) and urine (7%) as revealed by a mass balance experiment. PBRM was also evaluated for its toxicity in mice and it was found to be very well tolerated after weekly sc administration (30-405 mg/kg for 8 weeks) or by po administration (300-900 mg/kg for 4 weeks). Overall, these experiments represent important steps in the preclinical characterization of the pharmaceutical behavior of PBRM, as well as for its translation to clinical trials.

Erratum to pre-operative use of aspirin in patients undergoing coronary artery bypass grafting: a systematic review and updated meta-analysis.

[This corrects the article DOI: 10.21037/jtd.2018.05.187.].

Insight into the mode of action and selectivity of PBRM, a covalent steroidal inhibitor of 17ß-hydroxysteroid dehydrogenase type 1.

17ß-Hydroxysteroid dehydrogenase type 1 (17ß-HSD1) is involved in the biosynthesis of estradiol, the major bioactive endogenous estrogen in mammals, and constitutes an interesting therapeutic target for estrogen-dependent diseases. A steroidal derivative, 3-{[(16ß,17ß)-3-(2-bromoethyl)-17-hydroxyestra-1,3,5(10)-trien-16-yl]methyl} benzamide (PBRM), has recently been described as a non-estrogenic, irreversible inhibitor of 17ß-HSD1. However, the mode of action of this inhibitor and its selectivity profile have not yet been elucidated. We assessed PBRM potency via in vitro kinetic measurements. The mechanism of enzyme inactivation was also investigated using interspecies (human, mouse, pig and monkey) comparisons via both in vitro assays and in silico analysis. Mouse and human plasma protein binding of PBRM was determined, whereas its selectivity of action was studied using a wide range of potential off-targets (e.g. GPCR, hERG, CYPs, etc.). The affinity constant (Ki=368nM) and the enzyme inactivation rate (kinact=0.087min-1) values for PBRM were determined with purified 17ß-HSD1. PBRM was found to be covalently linked to the enzyme. A long delay period (i.e. 3-5days) is required to recover 17ß-HSD1 activity following a pretreatment of breast and placenta cell lines with PBRM. Mechanistic analyses showed important interspecies differences of 17ß-HSD1 inhibition which support the importance of inactivation for PBRM effect. Evidences of the potency and selectivity of action presented herein for this first non-estrogenic and steroidal covalent irreversible inhibitor of 17ß-HSD1 warrant its further development as a potential drug candidate for estrogen-dependent disorders.

The Aminosteroid Derivative RM-133 Shows In Vitro and In Vivo Antitumor Activity in Human Ovarian and Pancreatic Cancers.

Ovarian and pancreatic cancers are two of the most aggressive and lethal cancers, whose management faces only limited therapeutic options. Typically, these tumors spread insidiously accompanied first with atypical symptoms, and usually shift to a drug resistance phenotype with the current pharmaceutical armamentarium. Thus, the development of new drugs acting via a different mechanism of action represents a clear priority. Herein, we are reporting for the first time that the aminosteroid derivative RM-133, developed in our laboratory, displays promising activity on two models of aggressive cancers, namely ovarian (OVCAR-3) and pancreatic (PANC-1) cancers. The IC50 value of RM-133 was 0.8 µM and 0.3 µM for OVCAR-3 and PANC-1 cell lines in culture, respectively. Based on pharmacokinetic studies on RM-133 using 11 different vehicles, we selected two main vehicles: aqueous 0.4% methylcellulose:ethanol (92:8) and sunflower oil:ethanol (92:8) for in vivo studies. Using subcutaneous injection of RM-133 with the methylcellulose-based vehicle, growth of PANC-1 tumors xenografted to nude mice was inhibited by 63%. Quite interestingly, RM-133 injected subcutaneously with the methylcellulose-based or sunflower-based vehicles reduced OVCAR-3 xenograft growth by 122% and 100%, respectively. After the end of RM-133 treatment using the methylcellulose-based vehicle, OVCAR-3 tumor growth inhibition was maintained for ≥ 1 week. RM-133 was also well tolerated in the whole animal, no apparent sign of toxicity having been detected in the xenograft studies.

Chemical synthesis, cytotoxicity, selectivity and bioavailability of 5α-androstane-3α,17ß-diol derivatives.

Aminosteroid derivatives represent a new family of compounds with promising antiproliferative activity over different cancer cell lines. Among all the aminosteroid derivatives synthesised in our laboratory, we have identified E-37P as one of the more potent when tested in vitro. Unfortunately, the pharmacokinetic properties of E-37P decrease its effectiveness when tested in vivo. To improve the bioavailability and increase the efficiency of aminosteroid E-37P, two series of analog compounds were synthesised by classic chemical synthesis, they were then characterized, and the concentration that inhibits 50% of cell proliferation (IC50) was determined on different cell lines. RM-133, a 5α-androstane-3α,17ß-diol derivative with a quinoline nucleus at the end of the piperazine-proline side-chain at position 2ß and an ethinyl at position 17α, showed very good antiproliferative activity among the five cancer cell lines studied (IC50=0.1, 0.1, 0.1, 2.0 and 1.1 µM for HL-60, MCF-7, T-47D, LNCaP and WEHI-3, respectively). Moreover, the plasmatic concentration of RM-133 at 3h, when injected subcutaneously in rats, was 2.3-fold higher than that of E-37P (151 vs 64.8 ng/mL). Furthermore, RM-133 weakly inhibited the two representative liver enzymes, CYP3A4 and CYP2D6, indicating a very low risk of drug-drug interactions. The cytotoxicity of RM-133 against normal cells was tested on peripheral blood lymphocytes (PBL) obtained from different donors and previously activated with phytohemagglutinin-L. PBL responded differently to treatment with RM-133, we observed a stimulation of cell proliferation and/or cytotoxicity in a dose-dependent manner. Based on these results, additional studies are currently underway to evaluate the selectivity of our lead compound against normal cell lines in a more detailed fashion.

Discovery of a non-estrogenic irreversible inhibitor of 17ß-hydroxysteroid dehydrogenase type 1 from 3-substituted-16ß-(m-carbamoylbenzyl)-estradiol derivatives.

17ß-Hydroxysteroid dehydrogenase type 1 (17ß-HSD1) is thought to play a pivotal role in the progression of estrogen-sensitive breast cancer by transforming estrone (E1) into estradiol (E2). We designed three successive series of E2-derivatives at position C3 of the potent inhibitor 16ß-(m-carbamoylbenzyl)-E2 to remove its unwanted estrogenic activity. We report the chemical synthesis and characterization of 20 new E2-derivatives, their evaluation as 17ß-HSD1 inhibitors, and their proliferative (estrogenic) activity on estrogen-sensitive cells. The structure-activity relationship study provided a new potent and steroidal nonestrogenic inhibitor of 17ß-HSD1 named 3-{[(16ß,17ß)-3-(2-bromoethyl)-17-hydroxyestra-1(10),2,4-trien-16-yl]methyl}benzamide (23b). In fact, this compound inhibited the transformation of E1 into E2 by 17ß-HSD1 in T-47D cells (IC50 = 83 nM), did not inhibit 17ß-HSD2, 17ß-HSD7, 17ß-HSD12, and CYP3A4, and did not stimulate the proliferation of estrogen-sensitive MCF-7 cells. We also discussed the results of kinetic and molecular modeling (docking) experiments, suggesting that compound 23b is a competitive and irreversible inhibitor of 17ß-HSD1.

A new nonestrogenic steroidal inhibitor of 17ß-hydroxysteroid dehydrogenase type I blocks the estrogen-dependent breast cancer tumor growth induced by estrone.

17ß-Hydroxysteroid dehydrogenase type 1 (17ß-HSD1) converts estrone (E1) into estradiol (E2) and is expressed in many steroidogenic tissues and breast cancer cell lines. Because the potent estrogen E2 stimulates the growth and development of hormone-dependent diseases, inhibition of the final step of E2 synthesis is considered a promising strategy for the treatment of breast cancer. On the basis of our previous study identifying 16ß-(m-carbamoylbenzyl)-E2 (CC-156) as a lead compound for the inhibition of 17ß-HSD1, we conducted a number of structural modifications to reduce its undesired residual estrogenic activity. The steroid derivative PBRM [3-(2-bromoethyl)-16ß-(m-carbamoylbenzyl)-17ß-hydroxy-1,3,5(10)-estratriene] emerged as a potent inhibitor of 17ß-HSD1 with an IC(50) value of 68 nmol/L for the transformation of E1 into E2. When tested in the estrogen-sensitive breast cancer cell line T-47D and in mice, PBRM showed no estrogenic activity in the range of concentrations tested. Furthermore, with the purpose of evaluating the bioavailability of PBRM and CC-156 injected subcutaneously (2.3 mg/kg), we measured their plasmatic concentrations as a function of time, calculated the area under the curve (AUC(0-12h)) and showed a significant improvement for PBRM (772 ng*h/mL) compared with CC-156 (445 ng*h/mL). We next tested the in vivo efficiency of PBRM on the T-47D xenograft tumor model in female ovariectomized athymic nude mice. After a treatment with PBRM, tumor sizes in mice stimulated with exogenous E1 were completely reduced at the control group level (without E1 treatment). As a conclusion, PBRM is a promising nonestrogenic inhibitor of 17ß-HSD1 for the treatment of estrogen-dependent diseases such as breast cancer.

Crucial Role of 3-Bromoethyl in Removing the Estrogenic Activity of 17ß-HSD1 Inhibitor 16ß-(m-Carbamoylbenzyl)estradiol.

17ß-Hydroxysteroid dehydrogenase type 1 (17ß-HSD1) represents a promising therapeutic target for breast cancer treatment. To reduce the undesirable estrogenic activity of potent 17ß-HSD1 inhibitor 16ß-(m-carbamoylbenzyl)estradiol (1) (IC(50) = 27 nM), a series of analogues with a small functionalized side chain at position 3 were synthesized and tested. The 3-(2-bromoethyl)-16ß-(m-carbamoylbenzyl)-estra-1,3,5(10)-trien-17ß-ol (5) was found to be a potent inhibitor (IC(50) = 68 nM) for the transformation of estrone (E1) into estradiol (E2) and, most importantly, did not stimulate the proliferation of estrogen-sensitive MCF-7 cells, suggesting no estrogenic activity. From these results, the crucial role of a bromoalkyl side chain at carbon 3 was identified for the first time. Thus, this new inhibitor represents a good candidate with an interesting profile suitable for further studies including pharmacokinetic and in vivo studies.

Impact of estradiol structural modifications (18-methyl and/or 17-hydroxy inversion of configuration) on the in vitro and in vivo estrogenic activity.

It is well recognized that the majority of breast cancers are initially hormone-dependent and that 17ß-estradiol (17ß-E2) plays a crucial role in their development and progression. For this reason, using a compound able to block a specific enzyme involved in the last steps of the biosynthesis of 17ß-E2 remains a rational way to treat estrogen-dependent diseases such as breast cancer. The present study describes the biological in vitro and in vivo evaluation of a structural modification (inversion of C18-methyl group at position 13 from ß to α face) of 17ß-E2 (1) and 17α-estradiol (17α-E2; 2). The two epimers 18-epi-17ß-E2 (3) and 18-epi-17α-E2 (4) were obtained in two chemical steps by inversion of the C18-methyl of estrone using 1,2-phenylendiamine in refluxing acetic acid and reduction of ketone at position C17 with LiAlH(4). The new E2 isomers were tested on estrogen-sensitive cell lines (MCF-7 and T-47D), on estrogen-sensitive tissues (uterus and vagina of mice) and on estrogen receptor (ER) to determine their estrogenic potency relatively to natural estrogen 17ß-E2 (1). The results show that 18-epi-17ß-E2 (3) possesses the lower affinity for ER (RBA = 1.2%), the lower estrogenicity on estrogen-sensitive cells (1000 folds less estrogenic than 17ß-E2 in MCF-7) and no uterotrophic (estrogenic) activity when tested on mice. In fact, we observed the following order of estrogenicity: 18-epi-17ß-E2 (3)<18-epi-17α-E2 (4) << 17α-E2 (2)17ß-E2 (1). These results suggest that the inversion of C18-methyl of natural 17ß-E2 scaffold could be a useful strategy to decrease the estrogenicity of E2 derivatives used as enzyme inhibitors in the context of a treatment of estrogen-dependent diseases.

Synthesis and preliminary evaluation of a modified estradiol-core bearing a fused γ-lactone as non-estrogenic inhibitor of 17ß-hydroxysteroid dehydrogenase type 1.

A non-estrogenic inhibitor of 17ß-hydroxysteroid dehydrogenase type 1 (17ß-HSD1) was designed based on a modified 3-hydroxy-estra-1,3,5(10)-triene core having an additional five-member lactone ring and a benzamide group. The inhibitor was synthesized, fully characterized and tested for its ability to inhibit the enzyme activity. Estrogenicity was also investigated and tested on estrogen-dependent T-47D cell line. Interestingly, this steroid derivative showed inhibitory potency towards 17ß-HSD1 and did not present residual unwanted estrogenic activity.