Hyaluronan-enriched transfer medium (HETM) can improve the implantation rate in morphologically poor euploid blastocyst transfer.

PURPOSE: Hyaluronan-enriched transfer medium (HETM) could improve the clinical pregnancy rate (CPR) for patients with repeated implantation failures (RIF). In contrast, there have been seldom reports addressing the potentially beneficial effects of HETM for morphologically poor blastocysts (MPBLs). Our study aimed to evaluate whether the use of HETM would improve the CPR for the patients who were transferred with euploid MPBLs. METHODS: Patients who underwent single euploid blastocyst transfer between July 2020 and June 2022 were enrolled. We included only those blastocysts confirmed as euploid by PGT-A, and those blastocysts were transferred after thawing. The natural ovulatory cycle or hormone replacement cycle (HRC) protocol were used for endometrial preparation for frozen embryo transfer (FET). A total of 1,168 FET cycles were performed in the study period, including 954 cycles of morphologically good blastocysts (≥ 4BB in Gardner's classification), and 85 cycles of MPBLs, of which 47 were transferred using HETM in FET (the HETM group), and the remaining 38 were transferred with the medium without hyaluronan (the control group). We compared the CPR between these two groups. RESULTS: The characteristics of patients were similar between the HETM and control groups. The CPR in the HETM group was significantly higher than the control group (47.4% and 21.5%, respectively, p = 0.019). The multiple logistic regression analysis found that the use of HETM was a predictive factor of positive pregnancy outcomes (OR = 5.08, 95% CI = 1.62-16.0, p = 0.019). CONCLUSION: Our data suggests that HETM used in the euploid blastocyst transfer can improve the clinical pregnancy rates of morphologically poor blastocysts.

Transcriptomic profiling analysis of human endometrial stromal cells treated with autologous platelet-rich plasma.

Purpose: To clarify the mechanisms of intrauterine platelet-rich plasma (PRP) infusion that support embryo implantation in in vitro fertilization treatment. Methods: Blood and endometrial samples were collected from four infertile women. Human endometrial stromal cells (HESCs) were cultured and passaged equally into four cell culture dishes in each patient. Two were treated with PRP twice, and the other two were treated with vehicle. Subsequently, two cultures with and without PRP were decidualized with 8-bromoadenosine 3',5'-cyclic AMP and progesterone for 5 days. Results: The gene expression in undifferentiated or decidualized HESCs with and without PRP was compared. In the microarray analysis, 381 and 63 differentially expressed genes were detected in undifferentiated and decidualized HESCs, respectively. In the undifferentiated HESCs, PRP was found to promote the gene expression associated with cell growth, tissue regeneration, proinflammatory response, and antibiotic effects. In decidualized HESCs, PRP was found to attenuate the gene expression involved in cell proliferation and inflammation by inhibiting the expression of phosphoinositide 3-kinase signaling. Conclusions: Platelet-rich plasma regulates the reprogramming of cell proliferation and inflammation depending on menstrual cycle phases in an appropriate manner, suggesting that PRP has the potential to increase endometrial thickness in the proliferative phase and improve immune tolerance in the secretory phase.

Therapeutic efficacy of gentle endometrial curettage on antibiotic-resistant chronic endometritis in infertile women.

Purpose: To identify the efficacy of endometrial curettage on antibiotic-resistant chronic endometritis (CE) in infertile women. Methods: Of 1580 women with CE, 87 with antibiotic-resistant CE after two to five cycles of antibiotic treatment were recruited between 2019 and 2021. The women who underwent endometrial curettage without applying any force and, in the subsequent menstrual cycle, endometrial sampling for CD138 immunostaining without antibiotic use. Pregnancy outcomes after in vitro fertilization treatment were analyzed in women who did not desire endometrial curettage and in those with cured and persistent CE after endometrial curettage. Results: In 64 women who underwent endometrial curettage, the number of CD138-positive cells decreased from 28.0 ± 35.3 to 7.7 ± 14.0 (p < 0.0001), and CE in 41 women (64.1%) was cured (<5 CD138-positive cells). The pathological findings detected 3.1% of endometrial hyperplasia and 1.6% of endometrial cancer. The ongoing pregnancy rates in women aged ≤42 without endometrial curettage were significantly lower than those of women with cured and persistent CE (26.7%, 67.6%, and 57.1%, respectively, p = 0.03). Conclusions: Gentle endometrial curettage for antibiotic-resistant CE significantly decreased the number of CD138-positive cells, resulting in improved pregnancy outcomes regardless of remaining CE. Endometrial curettage is also important as a screening for endometrial malignancy.

Therapeutic efficacy of the optimization of thyroid function, thrombophilia, immunity and uterine milieu (OPTIMUM) treatment strategy on pregnancy outcomes after single euploid blastocyst transfer in advanced age women with recurrent reproductive failure.

Purpose: To clarify the efficacy of the OPtimization of Thyroid function, Thrombophilia, IMmunity and Uterine Milieu (OPTIMUM) treatment strategy on pregnancy outcomes after euploid blastocyst transfer in advanced age women with recurrent implantation failure (RIF) and/or recurrent pregnancy loss (RPL). Methods: Between January 2019 and May 2022, 193 consecutive women aged ≥40 years with RIF and/or RPL received single euploid blastocyst transfer. Before embryo transfer, 127 women underwent RIF/RPL testing. Chronic endometritis was treated with mainly antibiotics, aberrant high Th1/Th2 cell ratios with vitamin D and/or tacrolimus, overt/subclinical hypothyroidism with levothyroxine, and thrombophilia with low-dose aspirin. We compared pregnancy outcomes in the women who did and did not receive the OPTIMUM treatment strategy. Results: Women with RIF/RPL in the OPTIMUM group had significantly higher clinical pregnancy and livebirth rates than did those in the control group (clinical pregnancy rate of 71.7% and 45.5%, p < 0.001; livebirth rate of 64.6% and 39.4%, p = 0.001, respectively). However, preimplantation genetic testing for aneuploidy with and without OPTIMUM promoted low miscarriage rates with no significant difference between them (9.9%, and 13.3%, respectively; p = 0.73). Conclusions: The OPTIMUM treatment strategy improved clinical pregnancy rates after single euploid blastocyst transfer; but not miscarriage rates.

Therapeutic effects of an oral gonadotropin-releasing hormone receptor antagonist, relugolix, on preventing premature ovulation in mild ovarian stimulation for IVF.

PURPOSE: Can relugolix, a novel oral gonadotropin-releasing hormone receptor (GnRH) antagonist, function as an alternative ovulation inhibitor to GnRH antagonist injections? METHODS: This single-center, cross-sectional retrospective study compared premature ovulation rates and clinical outcomes in IVF treatment after mild ovarian stimulation with 40 mg of relugolix (relugolix group) or 0.25-mg injections of ganirelix acetate or cetrorelix acetate (injection group) between March 2019 and January 2020. Of 247 infertile women (256 IVF cycles) aged ≤42 years, 223 women (230 cycles) were evaluated. In the relugolix and injection groups, we compared 104 and 85 cycles after GnRH antagonist use before the LH surge (LH levels <10 mIU/ml) and 22 and 19 cycles during the LH surge (LH levels ≥10 mIU/ml), respectively. RESULTS: Before the LH surge, the ovulation rates in the two groups were very low (p = 0.838), however; during the LH surge, the cycles using relugolix had a high ovulation rate of 40.9% compared with no ovulation in the injection group (p = 0.002). There were no significant differences in embryo culture findings and pregnancy outcomes between the two groups. CONCLUSIONS: Although relugolix had a high ovulation suppressive effect, when the LH surge occurred, its effect was insufficient.

Recent progress in the development of high-performance bonded magnets using rare earth-Fe compounds.

Permanent magnets, and particularly rare earth magnets such as Nd-Fe-B, have attracted much attention because of their magnetic properties. There are two well-established techniques for obtaining sintered magnets and bonded Nd-Fe-B magnets. Powder metallurgy is used to obtain high-performance anisotropic sintered magnets. To produce bonded magnets, either melt-spinning or the hydrogenation, disproportionation, desorption, and recombination process is used to produce magnet powders, which are then mixed with binders. Since the development of Nd-Fe-B magnets, several kinds of intermetallic compounds have been reported, such as Sm2Fe17Nx and Sm(Fe,M)12 (M: Ti, V, etc.). However, it is difficult to apply a liquid-phase sintering process similar to the one used for Nd-Fe-B sintered magnets in order to produce high-performance Sm-Fe-based sintered magnets because of the low decomposition temperature of the compound and the lack of a liquid grain boundary phase like that in the Nd-Fe-B system. Therefore, bonded magnets are useful in the production of bulk magnets using these Sm-Fe-based compounds. This article reviews recent progress in our work on the development of high-performance bonded magnets using Nd2Fe14B and Sm2Fe17Nx compounds.

Novel approaches to the management of recurrent pregnancy loss: The OPTIMUM (OPtimization of Thyroid function, Thrombophilia, Immunity, and Uterine Milieu) treatment strategy.

PURPOSE: Does the OPtimization of Thyroid function, Thrombophilia, Immunity, and Uterine Milieu (OPTIMUM) treatment strategy, developed for treating repeated implantation failure (RIF), contribute to improving pregnancy outcomes in patients with a history of recurrent pregnancy loss (RPL)? METHODS: Between 2018 and 2019, women with RPL after two or more clinical pregnancy losses underwent RPL testing. We treated chronic endometritis with antibiotics, high Th1/Th2 cell ratios with vitamin D and/or tacrolimus, overt/subclinical hypothyroidism with levothyroxine, and thrombophilia with low-dose aspirin. Of 168 consecutive women aged ≤43 years, 115 underwent RPL testing. We compared 100 pregnancies (90 women) and 46 pregnancies (41 women) with and without the OPTIMUM treatment strategy, respectively. RESULTS: RPL testing identified intrauterine abnormalities in 66 (57.4%), elevated Th1/Th2 cell ratios in 50 (43.5%), thyroid dysfunction in 33 (28.7%), and thrombophilia in 33 (28.7%). The live birth rate in the OPTIMUM group was significantly higher than that in the control group among women aged <40 years (78.1% and 42.3%, respectively; p = 0.002), but no significant difference was observed in women aged ≥40 years (55.6% and 30.0%, respectively; p = 0.09). CONCLUSIONS: The OPTIMUM treatment strategy improved pregnancy outcomes in patients with not only RIF but also RPL.

Discovery of novel 2-(4-aryl-2-methylpiperazin-1-yl)-pyrimidin-4-ones as glycogen synthase kinase-3ß inhibitors.

We herein describe the results of further evolution of glycogen synthase kinase (GSK)-3ß inhibitors from our promising compounds containing a 3-methylmorpholine moiety. Transformation of the morpholine moiety into a piperazine moiety resulted in potent GSK-3ß inhibitors. SAR studies focused on the nitrogen atom of the piperazine moiety revealed that a phenyl group afforded potent inhibitory activity toward GSK-3ß. Docking studies indicated that the phenyl group on the piperazine nitrogen atom and the methyl group on the piperazine make cation-π and CH-π interactions with GSK-3ß respectively. 4-Methoxyphenyl analogue 29 showed most potent inhibitory activity toward GSK-3ß with good in vitro and in vivo pharmacokinetic profiles, and 29 demonstrated a significant decrease in tau phosphorylation after oral administration in mice.

Discovery of novel 2-(3-phenylpiperazin-1-yl)-pyrimidin-4-ones as glycogen synthase kinase-3ß inhibitors.

We herein describe the results of further evolution of glycogen synthase kinase (GSK)-3ß inhibitors from our promising compounds containing a 2-phenylmorpholine moiety. Transformation of the morpholine moiety into a piperazine moiety resulted in potent GSK-3ß inhibitors. SAR studies focused on the phenyl moiety revealed that a 4-fluoro-2-methoxy group afforded potent inhibitory activity toward GSK-3ß. Based on docking studies, new hydrogen bonding between the nitrogen atom of the piperazine moiety and the oxygen atom of the main chain of Gln185 has been indicated, which may contribute to increased activity compared with that of the corresponding phenylmorpholine analogues. Effect of the stereochemistry of the phenylpiperazine moiety is also discussed.

Generation of enterocyte-like cells with pharmacokinetic functions from human induced pluripotent stem cells using small-molecule compounds.

The small intestine plays an important role in all aspects of pharmacokinetics, but there is no system for the comprehensive evaluation of small-intestinal pharmacokinetics, including drug metabolism and absorption. In this study, we aimed to construct an intestinal pharmacokinetics evaluation system and to generate pharmacokinetically functional enterocytes from human induced pluripotent stem cells. Using activin A and fibroblast growth factor 2, we differentiated these stem cells into intestinal stem cell-like cells, and the resulting cells were differentiated into enterocytes in a medium containing epidermal growth factor and small-molecule compounds. The differentiated cells expressed intestinal marker genes and drug transporters. The expression of sucrase-isomaltase, an intestine-specific marker, was markedly increased by small-molecule compounds. The cells exhibited activities of drug-metabolizing enzymes expressed in enterocytes, including CYP1A1/2, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, UGT, and sulfotransferase. Fluorescence-labeled dipeptide uptake into the cells was observed and was inhibited by ibuprofen, an inhibitor of the intestinal oligopeptide transporter solute carrier 15A1/PEPT1. CYP3A4 mRNA expression level was increased by these compounds and induced by the addition of 1α,25-dihydroxyvitamin D3. CYP3A4/5 activity was also induced by 1α,25-dihydroxyvitamin D3 in cells differentiated in the presence of the compounds. All these results show that we have generated enterocyte-like cells that have pharmacokinetic functions, and we have identified small-molecule compounds that are effective for promoting intestinal differentiation and the gain of pharmacokinetic functions. Our enterocyte-like cells would be useful material for developing a novel evaluation system to predict human intestinal pharmacokinetics.

Discovery of novel 2-(alkylmorpholin-4-yl)-6-(3-fluoropyridin-4-yl)-pyrimidin-4(3H)-ones as orally-active GSK-3ß inhibitors for Alzheimer's disease.

We herein describe the results of further evolution of GSK-3ß inhibitors for Alzheimer's disease from our promising compounds with in vivo tau phosphorylation inhibitory activity by oral administration. Introduction of a low alkyl group instead of the phenyl group at the 3-position of the morpholine moiety aiming to improve pharmacokinetic profiles resulted in potent low molecular weight GSK-3ß inhibitors with good in vitro pharmacokinetic profiles, which also showed in vivo tau phosphorylation inhibitory activity by oral administration. Effect of the stereochemistry of the alkyl moiety is also discussed using docking models.

2-(2-Phenylmorpholin-4-yl)pyrimidin-4(3H)-ones; a new class of potent, selective and orally active glycogen synthase kinase-3ß inhibitors.

A series of 2-(2-phenylmorpholin-4-yl)pyrimidin-4(3H)-ones was synthesized and examined for their inhibitory activity against glycogen synthase kinase-3ß (GSK-3ß). We found 21, 29 and 30 to possess potent in vitro GSK-3ß inhibitory activity with good in vitro PK profiles. 21 demonstrated significant decrease of tau phosphorylation after oral administration in mice and excellent PK profiles.

Comparison of Pregnancy Outcomes Between Fresh Embryo Transfer in a Natural IVF Cycle and IUI Cycle Among Infertile Young Women.

Background: The purpose of the current study was comparing pregnancy outcomes for natural cycle in vitro fertilization (IVF) per fresh embryo transfer (ET) and oocyte pick-up (OPU) in intrauterine insemination (IUI). Methods: This was a retrospective cohort study of women who underwent either IUI (n=246) or OPU with fresh ET for natural cycle IVF (n=291), conducted between April 2017 and February 2018 at the Center for Reproductive Medicine and Implantation Research, Sugiyama Clinic Shinjuku, Tokyo, Japan. Patients in both groups did not receive ovarian stimulation and luteal support; gonadotropin-releasing agonist spray was administered 35 hr before OPU or IUI. The clinical pregnancy rate was compared between the IUI and IVF groups. Data analysis was based on the number of cycles. The p≦0.05 was considered significant. Results: The clinical pregnancy rate per OPU in the IVF group was higher than the one in IUI group (20.6% vs. 10.1%), and the difference was significant (p<0.01). The pregnancy rate for natural cycle IVF calculated per fresh ET was 36.8%. The miscarriage rate did not significantly differ between the IVF (4.1%) and IUI (8.0%) groups. Conclusion: Fresh ET in natural cycle IVF provides a higher implantation rate than IUI.

Effects of Periconceptional Multivitamin Supplementation on Folate and Homocysteine Levels Depending on Genetic Variants of Methyltetrahydrofolate Reductase in Infertile Japanese Women.

Methylenetetrahydrofolate reductase (MTHFR) has various polymorphisms, and the effects of periconceptional folic acid supplementation for decreasing neural tube defects (NTDs) risk differ depending on the genotypes. This study analyzed the effectiveness of multivitamin supplementation on folate insufficiency and hyperhomocysteinemia, depending on MTHFR polymorphisms. Of 205 women, 72 (35.1%), 100 (48.8%) and 33 (16.1%) had MTHFR CC, CT and TT, respectively. Serum folate and homocysteine levels in women with homozygous mutant TT were significantly lower and higher, respectively, than those in women with CC and CT. In 54 women (26.3% of all women) with a risk of NTDs, multivitamin supplementation containing folic acid and vitamin D for one month increased folate level (5.8 ± 0.9 to 19.2 ± 4.0 ng/mL, p < 0.0001) and decreased the homocysteine level (8.2 ± 3.1 to 5.8 ± 0.8 nmol/mL, p < 0.0001) to minimize the risk of NTDs in all women, regardless of MTHFR genotype. Regardless of MTHFR genotype, multivitamin supplements could control folate and homocysteine levels. Tests for folate and homocysteine levels and optimal multivitamin supplementation in women with risk of NTDs one month or more before pregnancy should be recommended to women who are planning a pregnancy.

Increasing number of implantation failures and pregnancy losses associated with elevated Th1/Th2 cell ratio.

PROBLEM: We aimed to assess whether an imbalance of T-helper (Th) 1 and Th2 cells contributes to implantation failure and pregnancy loss. METHOD OF STUDY: In this cross-sectional study, 197 consecutive patients with a history of repeated implantation failure (RIF) after three or more embryo transfer (ET) cycles and/or recurrent pregnancy loss (RPL) after two or more clinical pregnancy losses underwent Th cell testing. After excluding 42 women aged ≥44 and 9 with vitamin D supplementation, we recruited 146 women including 79 with RIF and 81 with RPL. Fourteen women had a history of both RIF and RPL. We also recruited 45 fertile women and 40 general infertile women without a history of in vitro fertilization treatment. This study was approved by the local ethics committee. RESULTS: There was no significant difference in IFN-γ-producing Th1 and IL-4-producing Th2 cell levels between the fertile and general infertile women, but Th1 cell levels and the Th1/Th2 cell ratio were significantly higher in the women with ≥4 ET cycles and ≥2 pregnancy losses than in the fertile and general infertile women. In the general infertile women, the total livebirth rates including natural conception after two ET cycles in the normal and high Th1/Th2 groups (Th1/Th2 <11.8 and ≥11.8, respectively) were 66.7% and 87.5%, respectively (p = .395). CONCLUSIONS: A high Th1/Th2 cell ratio was linked to ≥4 implantation failure cycles and ≥2 pregnancy losses but not to general infertility.

Impact of chronic endometritis on endometrial receptivity analysis results and pregnancy outcomes.

BACKGROUND: The aim of this study is to evaluate the relationship between chronic endometritis (CE) and a personalized window of implantation (WOI), identified by results of endometrial receptivity analysis (ERA), and pregnancy outcomes following embryo transfer (ET) based on the ERA outcomes. METHODS: The single-center, cross-sectional study was designed. The study population consisted of 101 infertile women who underwent endometrial sampling between June 2018 and February 2020. We recruited 88 patients who underwent ERA testing and immunohistochemistry of the plasma cell marker CD138 to diagnose CE within 3 months of testing. Subjects were divided into three groups as follows: 33 without CE (non-CE group); 19 with untreated CE at ERA testing (CE group); and 36 successfully treated for CE before ERA testing (cured-CE group). CE diagnosis was defined as ≥5 CD138-positive plasma cells per 10 random stromal areas at ×400 magnification. RESULTS: In non-CE, CE, and cured-CE groups, the numbers of CD138-positive cells were 0.7 ± 1.0, 28.5 ± 30.4, and 1.3 ± 1.3, respectively (p < .001). The rates of "receptive" endometrium in non-CE and cured-CE groups were 57.6% (19 women) and 50.0% (18 women), respectively; however, in the CE group, this rate was significantly lower than the other two groups (p = .009) at only 15.8% (3 women). After CE were treated prior or posterior to the ERA test in cured-CE or CE groups, the clinical pregnancy rates at the first ET in non-CE, CE, and cured-CE groups were 77.8% (21/27 cycles), 22.2% (4/18 cycles), and 51.7% (15/29 cycles), respectively (p < 0.001). CONCLUSION: CE had detrimental effects on the individual WOI, leading to embryo-endometrial asynchrony; therefore, diagnosis and treatment of CE should be done before ERA testing.

Laparoscopically-assisted transabdominal oocyte retrieval in an infertility patient with ovarian malposition.

Infertility patients with malpositioned ovaries have considerable difficulty conceiving naturally because of extended fallopian tubes and ovarian malposition; such patients turn for help to assisted reproductive technology (ART) treatment. For most of these patients, ovarian malposition prevents transvaginal oocyte retrieval, so the transabdominal approach for oocyte retrieval is required. One of our infertility patients presented with ovarian malposition, and laparoscopy-assisted transabdominal oocyte retrieval was performed. We performed a Gonadotropin-releasing hormone agonist (GnRH-a) long protocol with human menopausal gonadotropin (hMG) ovarian stimulation, and used a standard transvaginal probe through the anterior abdominal wall for ovarian imaging and monitoring of the growing follicles. The patient underwent laparoscopically-assisted transabdominal oocyte retrieval-9 oocytes were recovered, and 5 were fertilized, and 2 embryos were transferred to the patient's uterus. The patient became pregnant and a gestational sac was detectable by transvaginal ultrasonography, but she spontaneously miscarried. The patient then received several laparoscopically-assisted transabdominal oocyte retrievals and finally became pregnant following a thawed embryo transfer during a hormone replacement cycle, and now her pregnancy is going well.

[Aging and anti-aging of oocytes].

The functions of organs decrease as the age increases. The fecundity of women also decreases due to mainly the decreasing quality of oocytes. The recent change of life style makes the age of infertility patients elder and infertility treatments more difficult. The therapeutic strategy for the elder infertility patients is still chaotic. The precise evaluation for the ageing in the female genital organs should be developed and the treatment for the failure of fecundity due to aging must be overcome.

Recombinant-follicle stimulating hormone is more effective than urinary human menopausal gonadotropin in ovarian hyperstimulation for assisted reproductive technology treatment.

Aim: The aim of the present study was to establish a standard protocol for ovarian stimulation with gonadotropin-releasing hormone analog (GnRH-a) long protocol using recombinant-follicle stimulating hormone (rec-FSH) preparations for assisted reproductive technology (ART) treatment. Methods: In 86 patients who underwent ovarian stimulation with GnRH-a long protocol for ART treatment, 53 were stimulated by rec-FSH preparations (rec-FSH group) and the others were stimulated by urinary-hMG (u-hMG group) preparations. The subjects were randomly assigned to either of these preparations. Hormonal profiles, total doses of gonadotropins, duration of stimulation and ART results were compared in both groups. Results: The duration of stimulation was similar in both groups (9.2 ± 0.3 days and 9.2 ± 0.2 days, respectively). The total doses of gonadotropin in the rec-FSH group (1505.3 ± 29.2 IU) was significantly lower than those in the u-hMG group (2130.3 ± 54.6 IU, P < 0.0001). The FSH and LH values on the day of human chorionic gonadotropin (hCG) administration in the rec-FSH group were significantly lower than those in the u-hMG group. Pregnancy rates were 31.3% in the rec-FSH group and 33.3% in the u-hMG group, respectively. Conclusions: The present study showed that rec-FSH preparations were more potent than conventional u-hMG preparations and the protocol of the present study with rec-FSH was a new ovarian stimulation protocol with GnRH-a long protocol. (Reprod Med Biol 2007; 6: 27-32).

(R)-3'-(3-methylbenzo[b]thiophen-5-yl)spiro[1-azabicyclo[2,2,2]octane-3,5'-oxazolidin]-2'-one, a novel and potent alpha7 nicotinic acetylcholine receptor partial agonist displays cognitive enhancing properties.

Recent studies have suggested that the alpha7 nicotinic acetylcholine receptors play important roles in learning and memory. Herein, we describe our research of the structure-activity relationships (SAR) in a series of (S)-spiro[1-azabicyclo[2.2.2]octane-3,5'-oxazolidin]-2'-ones bearing various bicyclic moieties to discover novel alpha7 receptor agonists. Through a number of SAR studies on the series, we have found out that inhibition of CYP 2D6 isozyme, which was a primary obstacle for the previously identified compound, was avoidable by the introduction of bicyclic moieties. Chemical optimization of the series led to the identification of a novel and potent alpha7 nicotinic acetylcholine receptor partial agonist 23. This compound not only possessed high binding affinity (K(i) = 3 nmol/L) toward the alpha7 receptor but also showed agonistic activity even at a concentration of 0.1 micromol/L. In addition, compound 23 improved cognition in several rat models, which might suggest the potential of the alpha7 receptor partial agonist for the treatment of neurological disorders including cognitive dysfunction.