Increasing membrane polyunsaturated fatty acids sensitizes non-small cell lung cancer to anti-PD-1/PD-L1 immunotherapy.

Immune checkpoints inhibitors (ICIs) as anti-PD-1/anti-PD-L1 have been approved as first-line treatment in patients with non-small cell lung cancer (NSCLC), but only 25% of patients achieve durable response. We previously unveiled that estrogen receptor α transcriptionally up-regulates PD-L1 and aromatase inhibitors such as letrozole increase the efficacy of pembrolizumab. Here we investigated if letrozole may have additional immune-sensitizing mechanisms. We found that higher the level of PD-L1 in NSCLC, higher the activation of SREBP1c that transcriptionally increases fatty acid synthase and stearoyl-CoA desaturase enzymes, increasing the amount of polyunsaturated fatty acids (PUFAs). Letrozole further up-regulated SREBP1c-mediated transcription of lipogenic genes, and increased the amount of PUFAs, thereby leading to greater membrane fluidity and reduced binding between PD-L1 and PD-1. The same effects were observed upon supplementation with ω3-PUFA docosahexaenoic acid (DHA) that enhanced the efficacy of pembrolizumab in humanized NSCLC immune-xenografts. We suggest that PUFA enrichment in membrane phospholipids improves the efficacy of ICIs. We propose to repurpose letrozole or DHA as new immune-sensitizing agents in NSCLC.

Roxadustat alleviates metabolic traits in letrozole-induced PCOS mice.

Polycystic ovary syndrome (PCOS) is a highly prevalent disorder in women that is commonly accompanied by metabolic syndrome. Activation of the hypoxia-inducible factor (HIF) pathway is known to alleviate metabolic defects. Hence, this study utilized a preclinical PCOS mouse model to investigate the effects of chemically induced HIF activation on the metabolic traits of PCOS. Prepubertal letrozole treatment was used to generate a PCOS mouse model in the C57Bl6/J strain, and PCOS mice were orally treated with vehicle or roxadustat for six weeks from age 12 weeks onwards to induce HIF activation. Although the PCOS mice showed impaired glucose tolerance, increased insulin resistance, elevated blood lipids, and reduced muscle glycogen content, there was no difference in histological evaluations of white adipose tissue (WAT) or liver or in organ weights. Roxadustat treatment resulted in significant improvement in glucose tolerance (27 % reduction in area under the curve (AUC)values, p < 0.0001), fasting glucose levels (4.59 ±â€¯0.83 mmol/l vs 3.05 ±â€¯0.62 mmol/l, p < 0.0001) and insulin resistance (46 % reduction in homeostasis model assessment-insulin resistance (HOMA-IR) values, 6.76 ±â€¯3.72 vs 3.64 ±â€¯2.44, p = 0.019) compared to vehicle-treated mice without altering the body weight. Gene expression analyses with real-time quantitative polymerase chain reaction (RT-qPCR) and RNA sequencing revealed significant differences in gene expression in the tissues of PCOS mice compared to control mice, whereas the transcriptomic effects of roxadustat were mainly transient. However, immunohistochemistry revealed increased uncoupling protein 1 (UCP1) expression in WAT, which may indicate WAT browning related to HIF pathway activation.

Anastrozole vs Letrozole to Augment Height in Pubertal Males With Idiopathic Short Stature: A 3-Year Randomized Trial.

Context: Insufficient efficacy and safety data for off-label use of aromatase inhibitors to augment height in boys with short stature. Objective: To compare anastrozole and letrozole in treatment of idiopathic short stature in pubertal boys. Design: Open-label trial with 2 treatment arms. Setting: Pediatric Endocrine Clinic at Stanford. Participants: A total of 79 pubertal males ≥10 years with bone age (BA) ≤ 14 years, predicted adult height (PAH) < 5th percentile or >10 cm below mid-parental height. Intervention: Anastrozole 1.0 mg or letrozole 2.5 mg daily for up to 3 years. Main Outcome Measures: Annual hormone levels and growth parameters during treatment and a year posttherapy; annual BA and PAH (primary outcome measure); spine x-rays and dual energy X-ray absorptiometry at baseline and 2 years. Results: Compared with anastrozole (n = 35), letrozole (n = 30) resulted in higher testosterone levels, lower estradiol and IGF-1 levels, and slower growth velocity and BA advance. The PAH increase observed at year 1 in both groups did not persist at years 2 and 3. Change in PAH from baseline was not different between treatment groups. In groups combined, PAH gain over 3 years vs baseline was +1.3 cm (P = .043) in linear mixed models. Conclusion: Letrozole caused greater deviations than anastrozole in hormone levels, growth velocity, and BA advancement, but no group differences in PAH or side effects were found. Change in PAH after 2 to 3 years of treatment was minimal. The efficacy of AI as monotherapy for height augmentation in pubertal boys with idiopathic short stature may be limited, and safety remains an issue.

Letrozole co-treatment in an antagonist protocol for overweight women undergoing IVF treatment: a retrospective study.

BACKGROUND: Overweight women undergoing IVF treatment have lower success rates. Letrozole, an aromatase inhibitor, has been used as an adjunct for IVF treatment, but its specific effects in overweight women have not been investigated. This study was to explore the effects of letrozole co-treatment in an antagonist protocol for overweight infertile women undergoing IVF treatment. METHODS: This retrospective cohort study included overweight infertile women who underwent IVF/ICSI treatment and fresh embryo transfer (ET), with or without letrozole co-treatment in an antagonist protocol, from 2007 to 2021 at Shanghai Ninth People's Hospital (Shanghai, China). A total of 704 overweight infertile women were included: 585 women were in the antagonist group, and 119 women were in the letrozole co-treatment group. The primary outcome was the live birth rate after fresh ET. Propensity score-based patient-matching was employed to balance the covariates between the groups. Multivariate logistic regression analysis was also performed to estimate odds ratio (OR) and 95% confidence interval (CI) for association of letrozole co-treatment and the live birth outcome. RESULTS: Letrozole co-treatment induced significant changes in hormonal profile on the trigger day. The letrozole group exhibited a decrease in the total number of follicles compared to the antagonist group, but a higher proportion of large follicles at oocyte retrieval (P < 0.05). The quantity and quality of embryos were comparable between the two groups (P > 0.05). The letrozole co-treatment group had a significantly higher live birth rate than the control group (38.7% vs. 22.6%, P = 0.026). With multivariate logistic regression analysis, letrozole co-treatment was associated with higher odds of live birth after adjusting for potential confounding factors (adjusted OR = 2.00, 95% CI = 1.17-3.39, P = 0.011). Letrozole presented no significant associations with obstetrical or neonatal complications (P > 0.05). CONCLUSION: Letrozole co-treatment in an antagonist protocol may offer potential benefits for overweight infertile women undergoing IVF treatment. Further research is warranted to validate these findings and explore the broader implications for letrozole co-treatment.

Extended versus conventional letrozole regimen in patients with polycystic ovary syndrome undergoing their first ovulation induction cycle: a prospective randomized controlled trial.

STUDY QUESTION: Can an extended letrozole (LE) regimen result in a higher ovulatory rate than a conventional regimen in patients with polycystic ovary syndrome (PCOS) undergoing their first ovulation induction cycle? SUMMARY ANSWER: There was no statistical difference in ovulation rate between patients with PCOS using the extended LE regimen and those using the conventional LE regimen. WHAT IS KNOWN ALREADY: LE has become the first-line agent for ovulation induction. However, there is still a proportion of non-responsive cycles in patients with PCOS undergoing ovulation induction therapy with LE alone, and the extended LE regimen has been demonstrated to be a feasible method for inducing ovulation in these non-responders. Nevertheless, whether the extended regimen could be applied to all patients with PCOS as a first choice for the induction of ovulation remains to be explored. STUDY DESIGN SIZE DURATION: This was a prospective randomized controlled trial that included 148 female patients with PCOS who underwent their first ovulation induction cycle with LE from January 2021 to October 2022. PARTICIPANTS/MATERIALS SETTING METHODS: Participants were randomly assigned to receive an extended (5 mg LE daily for 7 days) or conventional regimen (5 mg LE daily for 5 days) for one treatment cycle. The ovulation rate was the primary outcome. Secondary outcomes included the clinical pregnancy rate, the number of preovulatory follicles, and the rate of multiple pregnancies. MAIN RESULTS AND THE ROLE OF CHANCE: The ovulation rate among patients receiving an extended LE regimen was slightly higher than the rate with a conventional LE regimen, but the difference did not reach statistical significance in either the intention-to-treat analysis (90.54% [67/74] vs 79.73% [59/74], P = 0.065; relative risk [95% CI]: 0.881 [0.768-1.009]) or the per-protocol analysis (90.54% [67/74] vs 84.29% [59/70], P = 0.257; relative risk [95% CI]: 0.931 [0.821-1.055]). The number of preovulatory follicles was nearly identical in the two groups (1.39 ± 0.62 vs 1.37 ± 0.59, P = 0.956), and no cases of ovarian hyperstimulation syndrome were observed. With regards to the endometrial parameters, the mean endometrium thickness was slightly thicker with the conventional LE regimen compared to that with the extended LE regimen, though with no statistical difference (9.27 ± 1.72 mm vs 9.57 ± 2.28 mm, P = 0.792). In the per-protocol analysis, the rates of clinical pregnancy (20.27% [15/74] vs 14.29% [10/70], P = 0.343; relative risk [95% CI]: 0.705 [0.34-1.463]) and live birth (13.51% [10/74] vs 11.43% [8/70], P = 0.705; relative risk [95% CI]: 0.846 [0.354-2.019]) did not differ significantly between treatment groups. Moreover, all conceptions were singletons without neonatal defects. LIMITATIONS REASONS FOR CAUTION: The major concerns regarding this study are its single-center and open-label nature. Additionally, the limited number of lean patients with PCOS with a mean body mass index of 23-25 kg/m2 enrolled in our trial also restricted the generalizability of our findings. WIDER IMPLICATION OF THE FINDINGS: A change from the standard strategy of ovulation induction in patients with PCOS is not advisable, because a statistically superior effect of the extended LE regimen over a conventional regimen was not detected. The extended LE regimen could be applied with caution in a specific population who failed to respond to a conventional regimen rather than all the patients with PCOS during ovulation induction. Additional prospective trials with larger sample sizes and different PCOS subgroups are needed to assess the ovulatory effects of various LE treatment durations. STUDY FUNDING/COMPETING INTERESTS: This study was funded by the Shanghai First Maternity and Infant Hospital, affiliated with Tongji University School of Medicine (grant numbers: 2023B03 to Y.F., 2023B18 to X.Z., and 2020RC02 to Y.F.). The authors report no conflicts of interest. TRIAL REGISTRATION NUMBER: Chinese Clinical Trial Registry (ChiCTR2100042082). TRIAL REGISTRATION DATE: 13 January 2021. DATE OF FIRST PATIENT'S ENROLMENT: 21 January 2021.

Phytochemicals-based investigation of Rubia cordifolia pharmacological potential against letrozole-induced polycystic ovarian syndrome in female adult rats: In vitro, in vivo and mechanistic approach.

Polycystic Ovarian Syndrome (PCOS) is a metabolic, reproductive, and endocrine disorder affecting women of fertile age. This study aimed to formulate a phytochemicals-based standardized aqueous ethanolic extract of Rubia cordifolia (SERC) to explore its pharmacological potential in PCOS-induced female rats and elucidate its mechanism. HPLC analysis revealed the presence of phytochemicals such as chlorogenic acid, p-coumaric acid, gallic acid, and kaempferol. Thirty female adult rats were divided into two groups for induction of PCOS (5 female rats in the normal control group + 25 female rats in the disease-induced group). PCOS was induced by administering letrozole (1 mg/kg p.o.) for 6 weeks. After PCOS induction, animals of the disease-induced group were divided into five groups: one group used as disease control (PCOS) group, one group on metformin (20 mg/kg), and three groups on SERC (200, 400, and 600 mg/kg). Histopathological analysis showed that PCOS induction reduced corpus luteum and developing follicles and increased cystic follicles. In comparison, SERC treatment improved ovulation with more primary and developing follicles. SERC reduced the serum insulin, LH surge, and testosterone levels while improving the FSH, estrogen, and progesterone serum levels. SERC significantly improved the oxidation status of the liver and normalized the lipid profile and liver function markers. In conclusion, SERC treated PCOS, and the suggested mechanism might be the restoration of aromatase activity and background inflammatory status improvement in ovaries.

Pterostilbene Ameliorates Cognitive Impairment in Polycystic Ovary Syndrome Rat Model through Improving Insulin Resistance via the IRS-1/PI3K/Akt/GSK-3ß Pathway: A Comparative Study with Metformin.

Polycystic ovary syndrome (PCOS) is an intricate endocrine disorder that targets millions of women globally. Recent research has drawn attention to its association with cognitive impairment and Alzheimer's disease (AD) risk, yet the exact mechanism remains elusive. This study aimed to explore the potential role of PCOS-associated insulin resistance (IR) and inflammation in linking PCOS to AD pathogenesis. It additionally investigated the therapeutic merits of pterostilbene (PTS) in ameliorating PCOS and associated cognitive deficits in comparison to metformin (MET). Rats were divided into five groups; vehicle group, PTS group [30 mg/kg, per os (p.o.) for 13 days], and the remaining three groups received letrozole (1 mg/kg, p.o. for 21 days) to represent the PCOS, PCOS + MET (300 mg/kg, p.o. for 13 days), and PCOS + PTS groups, respectively. Behavioral tests were conducted, along with a histopathological investigation of brains and ovaries. Assessment of serum hormonal profile and hippocampal IRS-1/PI3K/AKT/GSK-3ß insulin signaling pathway components were performed. PTS rats exhibited improved insulin sensitivity and hormonal profile, besides enhanced neurobehavioral tests performance and histopathological findings. These effects may be attributed to modulation of the IRS-1/PI3K/AKT/GSK-3ß pathway, reducing GSK-3ß activity, and mitigating Tau hyperphosphorylation and Aß accumulation in the brain. Likewise, PTS attenuated nuclear factor kappa B-mediated inflammation and reversed AChE elevation, suggesting multifaceted neuroprotective effects. Comparatively, PTS showed outcomes similar to those of MET in most parameters. The obtained findings validated that dysregulated insulin signaling in PCOS rats detrimentally affects cognitive function, which is halted by PTS, unveiling the potential of PTS as a novel therapy for PCOS and related cognitive deficits.

Pregnancy outcomes after superovulation-intrauterine insemination (SO-IUI) using gonadotropins versus letrozole in the obese population.

PURPOSE: To compare fertility outcomes of obese patients (body mass index [BMI] ≥ 30 kg/m2) undergoing superovulation and intrauterine insemination (SO-IUI) using gonadotropins versus letrozole. METHODS: A single centre retrospective cohort study of obese patients undergoing SO-IUI using gonadotropins or letrozole between January/2019 and June/2022. Primary outcome was clinical pregnancy rate (intrauterine pregnancy with positive fetal heart rate). Secondary outcomes included rates of multifollicular development, multiple pregnancy, spontaneous abortion and cycle cancellation. Subgroup analysis was done stratifying by obesity class. A multivariate logistic regression model was used for primary/secondary outcomes, adjusting for clinically determined covariates. RESULTS: Out of 802 total identified SO-IUI cycles, 715 cycles were completed (518-gonadotropins and 197-letrozole cycles). The clinical pregnancy rates were not significantly different in obese patients undergoing SO-IUI with gonadotropins versus letrozole when adjusted for age, gravidity, parity, cause of infertility, IUI cycle number, endometrial thickness, sperm source and post-wash motile sperm count (adjusted odds ratio [aOR] 1.37, 95% confidence interval [CI] 0.72-2.59). Similarly, no significant associations were found in spontaneous abortion (aOR1.46, 95%CI 0.42-5.08), multiple pregnancy (aOR1.33, 95%CI 0.20-8.88) or cancellation rates (OR0.89, 95%CI 0.55-1.45) between the two groups. The rates of multifollicular development were also comparable between the two groups (aOR0.51, 95% CI 0.19-1.38). For cycles involving gonadotropins, higher BMI classes required higher total gonadotropin dose (p < 0.001). CONCLUSION: After adjusting for patient and cycle factors, gonadotropins and letrozole led to comparable odds of achieving pregnancy in obese patients undergoing SO-IUI. Future research in the obese population will help to better understand how to optimize fertility treatments for this growing population.

The Beneficial Effects of Lacticaseibacillus paracasei subsp. paracasei DSM 27449 in a Letrozole-Induced Polycystic Ovary Syndrome Rat Model.

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder affecting women of reproductive age globally. Emerging evidence suggests that the dysregulation of microRNAs (miRNAs) and gut dysbiosis are linked to the development of PCOS. In this study, the effects of Lacticaseibacillus paracasei subsp. paracasei DSM 27449 (DSM 27449) were investigated in a rat model of PCOS induced by letrozole. The administration of DSM 27449 resulted in improved ovarian function, reduced cystic follicles, and lower serum testosterone levels. Alterations in miRNA expressions and increased levels of the pro-apoptotic protein Bax in ovarian tissues were observed in PCOS-like rats. Notably, the administration of DSM 27449 restored the expression of miRNAs, including miR-30a-5p, miR-93-5p, and miR-223-3p, leading to enhanced ovarian function through the downregulation of Bax expressions in ovarian tissues. Additionally, 16S rRNA sequencing showed changes in the gut microbiome composition after letrozole induction. The strong correlation between specific bacterial genera and PCOS-related parameters suggested that the modulation of the gut microbiome by DSM 27449 was associated with the improvement of PCOS symptoms. These findings demonstrate the beneficial effects of DSM 27449 in ameliorating PCOS symptoms in letrozole-induced PCOS-like rats, suggesting that DSM 27449 may serve as a beneficial dietary supplement with the therapeutic potential for alleviating PCOS.

Progestin-primed ovarian stimulation with letrozole using different doses of medroxyprogesterone acetate per day: a retrospective cohort study.

Background: In the progestin-primed ovarian stimulation protocol, the oral administration of medroxyprogesterone acetate has been observed to effectively inhibit the LH surge during ovarian stimulation in patients experiencing infertility. Nevertheless, the use of utilizing medroxyprogesterone acetate during ovarian stimulation can result in more pronounced pituitary suppression, potentially necessitating increased doses of gonadotropins and extended treatment durations. Therefore, it is necessary to determine the optimal dose of medroxyprogesterone acetate, aiming to use relatively lower concentrations of medroxyprogesterone acetate to effectively and safely suppress early LH surges. Method: This retrospective cohort study included 710 patients who underwent cycles of in vitro fertilization or intracytoplasmic sperm injection and were subjected the progestin-primed ovarian stimulation protocol utilizing letrozole between from 1st January 2021 to 31st December 2021. The study population was divided into low, medium, and high concentration groups based on the daily dosage of medroxyprogesterone acetate.The primary focus of this investigation was on the cumulative live birth rate. Secondary outcomes encompassed the occurrence of a premature surge in luteinizing hormone, the quantity of retrieved oocytes, viable embryos, and high-quality embryos, as well as clinical pregnancy rate, abortion rate, ectopic pregnancy rate, and multiple pregnancy rate. Results: In this study, significant differences were observed among three groups in various parameters including body mass index, baseline levels of Anti-Müllerian hormone and luteinizing hormone, antral follicle count, total dose of gonadotropin, and duration of gonadotropin administration (p<0.05). The number of oocytes and viable embryos were significantly higher in medium group and higher than those in the low dose group. Following adjustments for confounding factors related to medroxyprogesterone acetate for various outcome measures, we conducted multiple regression analysis to investigate the independent effects of daily medroxyprogesterone acetate dosage within the combined progestin-primed ovarian stimulation and letrozole protocol. Following multivariable regression analysis, no disparities were found in embryo characteristics (number of oocytes retrieved, number of available embryos, number of high-quality embryos) or pregnancy outcomes (clinical pregnancy rate, cumulative live birth rate) among the three groups. Conclusion: Progestin-primed ovarian stimulation with letrozole using different dose of medroxyprogesterone acetate per day was comparable in terms of the number of oocytes retrieved, the number of high-quality embryos, clinical pregnancy rate and cumulative live birth rate after frozen embryo transfer.

Secondary Analysis of Human Bulk RNA-Seq Dataset Suggests Potential Mechanisms for Letrozole Resistance in Estrogen-Positive (ER+) Breast Cancer.

Estrogen receptor-positive (ER+) breast cancer is common among postmenopausal women and is frequently treated with Letrozole, which inhibits aromatase from synthesizing estrogen from androgens. Decreased estrogen slows the growth of tumors and can be an effective treatment. The increase in Letrozole resistance poses a unique problem for patients. To better understand the underlying molecular mechanism(s) of Letrozole resistance, we reanalyzed transcriptomic data by comparing individuals who responded to Letrozole therapy (responders) to those who were resistant to treatment (non-responders). We identified SOX11 and S100A9 as two significant differentially expressed genes (DEGs) between these patient cohorts, with "PLK1 signaling events" being the most significant signaling pathway. We also identified PRDX4 and E2F8 gene products as being the top mechanistic transcriptional markers for ER+ treatment resistance. Many of the significant DEGs that we identified play a known role in ER+ breast cancer or other types of cancer, which partially validate our results. Several of the gene products we identified are novel in the context of ER+ breast cancer. Many of the genes that we identified warrant further research to elucidate the more specific molecular mechanisms of Letrozole resistance in this patient population and could potentially be used as prognostic markers with further wet lab validation. We anticipate that these findings could contribute to improved detection and therapeutic outcomes in aromatase-resistant ER+ breast cancer patients.

The NEOLETRIB trial: neoadjuvant treatment with Letrozole and Ribociclib in ER-positive, HER2-negative breast cancer.

Chemotherapy is used as neoadjuvant therapy for all subgroups of breast cancer, including ER-positive, and HER2-negative cases. However, studies have suggested that using aromatase inhibitors combined with CDK4/6-inhibitors might be an appropriate alternative in selected patients. Thus, the NEOLETRIB trial evaluates the response of ER-positive, HER2-negative luminal A/B breast cancer to the combination of letrozole and ribociclib in the neoadjuvant setting. Comprehensive molecular biology procedures, including sequential single-cell RNA-sequencing of tumor biopsies, are performed during 6 months of treatment with extensive biobanking of blood samples, tumor biopsies and gut microbiome specimens. Our findings will hopefully contribute to an improved selection of patients who may benefit from this drug combination and give new insights into the intra-tumoral changes during this treatment.Trial registration number: NCT05163106 (ClinicalTrials.gov).

[Box: see text].

Luteal phase support with oral progesterone improves live birth rate in intrauterine insemination cycles using letrozole.

RESEARCH QUESTION: Does luteal phase support (LPS) with oral progesterone improve the live birth rate (LBR) in patients undergoing intrauterine insemination (IUI) cycles with letrozole? DESIGN: This retrospective cohort study included 1199 IUI cycles with letrozole between January 2017 and December 2021. A nearest neighbour random matching approach was employed to pair the LPS group and the control group in a 1:2 ratio. Eight variables were chosen for matching in the propensity score matching (PSM) model: age; body mass index; duration of infertility; cause(s) of infertility; antral follicle count; basal concentration of FSH; rank of IUI attempts; and leading follicle size. LBR was selected as the primary outcome. RESULTS: In total, 427 LPS cycles were matched with 772 non-LPS (control) cycles after PSM. The LBR was significantly higher in the LPS group compared with the control group (19.7% versus 14.5%; P = 0.0255). The clinical pregnancy rate (23.2% versus 17.6%; P = 0.0245) and ongoing pregnancy rate (20.6% versus 15.8%; P = 0.0437) were also significantly higher in the LPS group. The biochemical pregnancy rate, ectopic pregnancy rate and miscarriage rate were similar in the two groups (P > 0.05). The intergroup comparison revealed no significant variances in terms of gestational age, mode of delivery, ectopic pregnancy rate or abortion rate. Furthermore, there were no significant differences in birth weight or birth length between the two groups. CONCLUSIONS: Luteal support with oral progesterone significantly improved the LBR in IUI cycles with letrozole, but did not affect neonatal outcomes.

Potential exacerbation of polycystic ovary syndrome by saccharin sodium Via taste receptors in a letrozole rat model.

The most common cause of anovulatory infertility is polycystic ovarian syndrome (PCOS), which is closely associated with obesity and metabolic syndrome. Artificial sweetener, notably saccharin sodium (SS), has been utilized in management of obesity in PCOS. However, accumulating evidence points towards SS deleterious effects on ovarian physiology, potentially through activation of ovarian sweet and bitter taste receptors, culminating in a phenotype reminiscent of PCOS. This research embarked on exploration of SS influence on ovarian functions within a PCOS paradigm. Rats were categorized into six groups: Control, Letrozole-model, two SS groups at 2 dose levels, and two groups receiving 2 doses of SS with Letrozole. The study underscored SS capability to potentiate PCOS-related anomalies. Elevated cystic profile with outer thin granulosa cells, were discernible. This owed to increased apoptotic markers as cleaved CASP-3, mirrored by high BAX and low BCL-2, with enhanced p38-MAPK/ERK1/2 pathway. This manifestation was accompanied by activation of taste receptors and disruption of steroidogenic factors; StAR, CYP11A1, and 17ß-HSD. Thus, SS showed an escalation in testosterone, progesterone, estrogen, and LH/FSH ratio, insinuating a perturbation in endocrine regulation. It is found that there is an impact of taste receptor downstream signaling on ovarian steroidogenesis and apoptosis instigating pathophysiological milieu of PCOS.

Strong Early Impact of Letrozole on Ovulation Induction Outperforms Clomiphene Citrate in Polycystic Ovary Syndrome.

Polycystic ovary syndrome is a common endocrine disorder, characterized by hyperandrogenism and/or chronic oligo/anovulation, which leads to infertility. The aim of this systematic review and meta-analysis was to explore the efficacy of letrozole compared with clomiphene citrate for ovulation induction in women with polycystic ovarian syndrome. The study protocol has been registered with PROSPERO (registration number CRD42022376611). The literature search included randomized clinical trials. We conducted our systematic literature search across three medical databases: MEDLINE (via PubMed), Cochrane Library (CENTRAL), and Embase. The data synthesis employed a random effects model. Out of the 1994 articles screened, 25 studies fulfilled the inclusion criteria. The letrozole group exhibited a significant increase in endometrial thickness (mean difference = 1.70, confidence interval: 0.55-2.86; I2 = 97%, p-value = 0.008). The odds of ovulation (odds ratio = 1.8, confidence interval: 1.21-2.69; I2 = 51%, p-value = 0.010) and pregnancy (odds ratio = 1.96, confidence interval: 1.37-2.81; I2 = 32%, p-value = 0.002) were significantly higher. The resistance index of the subendometrial arteries showed a significant decrease (mean difference = -0.15, confidence interval: -0.27 to -0.04; I2 = 92%, p-value = 0.030). Women diagnosed with polycystic ovarian syndrome and treated with letrozole for ovulation induction had increased ovulation and pregnancy rates and increased endometrial thickness. The lower resistance index of subendometrial arteries can enhance intrauterine circulation, creating more favorable conditions for embryo implantation and development.

Effect of aromatase inhibitors for preventing ovarian hyperstimulation syndrome in infertile patients undergoing in vitro fertilization: a systematic review and meta-analysis.

PURPOSE: To summarize the findings of relevant randomized controlled trials (RCTs) and conduct a meta-analysis to investigate the potential effect of aromatase inhibitors on preventing moderate to severe ovarian hyperstimulation syndrome (OHSS) in infertile women undergoing in vitro fertilization (IVF). METHODS: We searched for relevant RCTs in electronic databases, including MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov (from inception to August 2023). In addition, we manually searched the related reviews and reference lists of included studies for further relevant studies. We included RCTs where aromatase inhibitors prescribed either during controlled ovarian stimulation (COS) or in early luteal phase. The meta-analysis was performed using RevMan 5.4.1 software. The primary outcome was the incidence of moderate to severe OHSS. A descriptive analysis was conducted in cases where a meta-analysis was not feasible due to heterogeneity or lack of comparable data. RESULTS: 2858 records were retrieved and 12 RCTs were finally included. Letrozole was administered in the treatment group during COS in seven RCTs, whereas in the early luteal phase in five RCTs. Compared with the control group, the risk of moderate to severe OHSS significantly reduced by 55% in the letrozole group (RR 0.45, 95% CI 0.32 to 0.64, I2 = 0%, 5 RCTs, 494 patients). Moreover, serum estradiol (E2) levels on hCG trigger day significantly decreased with the administration of letrozole during COS (MD -847.23, 95% CI -1398.00 to -296.47, I2 = 93%, 5 RCTs, 374 patients). And serum E2 levels on the 4th, 5th and 7th to 10th day after hCG trigger were also significantly lower than those in the control group when letrozole was administered in the early luteal phase. CONCLUSIONS: Patients with high risk of OHSS probably benefit from letrozole, which has been revealed to reduce the incidence of moderate to severe OHSS by this systematic review. However, the very limited number of participants and the quality of the included studies does not allow to recommend letrozole for the prevention of severe OHSS.

Pharmacological non-hormonal treatment options for male infertility: a systematic review and network meta-analysis.

BACKGROUND: Male factor infertility affect up to 50% of couples unable to conceive spontaneously. Several non-hormonal pharmacological treatments have been proposed to boost spermatogenesis and increase chances of conception in men with infertility. Still, no clear evidence exists on the most effective treatment strategy. OBJECTIVE: We aimed to compare the effectiveness of non-hormonal pharmacological treatment options for men with infertility using a systematic review and network meta-analysis. METHODS: We searched MEDLINE, EMBASE, and CENTRAL until October 2023 for randomised/quasi-randomised trials that evaluated any non-hormonal pharmacological treatment options for men with idiopathic semen abnormalities or those with hypogonadism. We performed pairwise and network meta-analyses using a random effect model. We assessed risk of bias, heterogeneity, and network inconsistency. We calculated the mean rank and the surface under the cumulative ranking curve (SUCRA) for each intervention the maximum likelihood to achieve each of reported outcomes. We reported primarily on sperm concentration and other important semen and biochemical outcomes using standardised mean difference (SMD) and 95% confidence-intervals(CI). RESULTS: We included 14 randomised trials evaluating four treatments (Clomiphene citrate, Tamoxifen, Aromatase inhibitors, anti-oxidants) and their combinations in 1342 men. The overall quality of included trials was low. Sperm concentration improved with clomiphene compared to anti-oxidants (SMD 2.15, 95%CI 0.78-3.52), aromatase inhibitor (SMD 2.93, 95%CI 1.23-4.62), tamoxifen (SMD - 1.96, 95%CI -3.57; -0.36) but not compared to placebo (SMD - 1.53, 95%CI -3.52- 0.47). Clomiphene had the highest likelihood to achieve the maximum change in sperm concentration (SUCRA 97.4). All treatments showed similar effect for sperm motility, semen volume, and normal sperm morphology. FSH levels showed significant improvement with clomiphene vs.anti-oxidant (SMD 1.48, 95%CI 0.44-2.51) but not compared to placebo. The evidence networks for LH and testosterone suffered from significant inconsistency (p = 0.01) with similar trend of improvement with clomiphene compared to other treatments but not compared to placebo. CONCLUSION: There is insufficient evidence to support the routine use of Clomiphene, tamoxifen, and aromatase inhibitors to optimise semen parameters in men with infertility. Future randomised trials are needed to confirm the efficacy of clomiphene in improving fertility outcomes in men. PROSPERO: CRD42023430179.

The Efficacy of Letrozole Co-Treatment in an Antagonist Protocol for Women with Polycystic Ovary Syndrome Undergoing IVF: A Retrospective Study.

Objective: Our objective was to investigate the efficacy of letrozole co-treatment in an antagonist protocol for infertile women with polycystic ovary syndrome (PCOS). Patients and Methods: This retrospective cohort study included infertile women with PCOS undergoing IVF/ICSI with and without letrozole co-treatment in an antagonist protocol from 2007-2021 at Shanghai Ninth People's Hospital (Shanghai, China). A total of 1559 participants were enrolled, with 1227 women in the antagonist group and 332 women in the letrozole co-treatment group. Propensity score-based patient-matching model was conducted to balance covariates between the groups. The primary outcome was the number of retrieved oocytes, with secondary outcomes including endocrine parameters, ovarian stimulation outcomes, pregnancy outcomes, and obstetrical and neonatal complications. Results: Letrozole co-treatment induced significant changes in hormonal regulation, increased the percentage of large follicles, and resulted in fewer retrieved oocytes (P < 0.05). However, there was no negative impact on the number of usable embryos or good-quality embryos (P > 0.05). The live birth rates following fresh embryo transfer were comparable between the letrozole and control groups (single embryo transfer: 28.9% vs 29.7%, P > 0.05; double embryo transfer: 37.3% vs 45.6%, P > 0.05). Additionally, there were no significant differences between the two groups in the live birth rate per patient after frozen embryo transfer and the cumulative live birth rate (P > 0.05). No significant differences in obstetrical and neonatal complications were observed between the groups (P > 0.05). Conclusion: The addition of letrozole to the antagonist protocol for women with PCOS undergoing IVF induces a higher percentage of large follicles during oocyte retrieval, while reducing the overall number of retrieved oocytes. Moreover, the use of letrozole demonstrates comparable clinical outcomes following embryo transfers. These findings highlight the potential application of letrozole in an antagonist protocol for women with PCOS.

Efficacy of letrozole for the treatment of tubal ectopic pregnancy: A meta-analysis.

BACKGROUND: Tubal ectopic pregnancy (EP) is a life-threatening condition, especially if undiagnosed or misdiagnosed, tipically in low income countries and/or where women have limited access to health care. The current management protocol of tubal EP consists of either surgical management, or medical management with methotrexate. Recent studies, while few, have suggested that letrozole, an aromatase inhibitor, may play a role in the medical treatment of tubal EP. OBJECTIVES: To evaluate the effectiveness of letrozole alone in the medical treatment of tubal EP. SEARCH STRATEGY: Electronic databases were searched until 31 December 2023. SELECTION CRITERIA: Retrospective or prospective studies reporting the treatment of tubal EP with letrozole alone were considered eligible for inclusion. DATA COLLECTION AND ANALYSIS: Pooled results were expressed as OR with 95 %CI. Heterogeneity was assessed using Higgins I2. Subgroup analysis was performed to compare outcomes according to time after intervention. Subgroup differences were checked through χ2 test. RESULTS: A total of 152 patients were included. Seventy-nine patients (51.97 %) were treated with letrozole, 39 patients (16.54 %) with methotrexate, and 34 patients (31.49 %) underwent surgical treatment. Pooled data analysis supports the consistency of the effect of letrozole in reducing ß-hCG over time at a comparable rate among studies, and that treatment with letrozole is superior to surgery and has the same efficacy as methotrexate. However, all the included studies were judged at high risk of bias in terms of study design, sample representativeness, and sampling technique. Furthermore, short and long term side effects were not reported in any of the included studies. CONCLUSIONS: Letrozole is a promising alternative to methotrexate and surgical therapy in the treatment of tubal EP. Although this meta-analysis suggests efficacy and low hazard of the drug and encourages its application, the data available today remain extremely sparse, which weakens any claims that can be made, and is not sufficient to assert that letrozole is safe and effective in the treatment of EPs. There is an absolute need for randomized studies with accurate patient selection, fixed doses, large sample sizes, and reporting of short- and long-term side effects to refute or confirm this assumption.

A comparison of letrozole regimens for ovulation induction in women with polycystic ovary syndrome.

Objective: To determine the optimal letrozole regimen for ovulation induction (OI) in women with polycystic ovary syndrome (PCOS). Design: Retrospective cohort study. Setting: Single academic fertility clinic from 2015-2022. Patients: A total of 189 OI cycles in 52 patients with PCOS. Interventions: Patients were prescribed 1 of 4 letrozole regimens (group 1: 2.5 mg for 5 days, group 2: 2.5 mg for 10 days, group 3: 5 mg for 5 days, and group 4: 5 mg for 10 days). Main outcome measures: The primary outcome was ovulation, and secondary outcomes included multifollicular development, and clinical pregnancy rate, which were analyzed with binary logistic regression. Kaplan-Meier cumulative response curves and a Cox proportional hazard regression model were used for time-dependent analyses. Results: Mean age was 30.9 years (standard deviation [SD], 3.6) and body mass index was 32.1 kg/m2 (SD, 4.0). Group 2 (odds ratio [OR], 9.12; 95% confidence interval [CI], 1.92-43.25), group 3 (OR, 3.40; 95% CI, 1.57-7.37), and group 4 (OR, 5.94; 95% CI, 2.48-14.23) had improved ovulation rates after the starting regimen as compared with group 1. Cumulative ovulation rates exceeded 84% in all groups, yet those who received 5 mg and/or 10 days achieved ovulation significantly sooner. Multifollicular development was not increased in groups 2-4 as compared with group 1. Groups 2-4 also demonstrated improved time to pregnancy. Conclusions: Ovulation rates are improved when starting with letrozole at 5 mg and/or a 10-day extended course as compared with the frequently-used 2.5 mg for 5 days. This may shorten time to ovulation and pregnancy.