Lasofoxifene as a potential treatment for aromatase inhibitor-resistant ER-positive breast cancer.

BACKGROUND: Breast cancers treated with aromatase inhibitors (AIs) can develop AI resistance, which is often driven by estrogen receptor-alpha (ERα/ESR1) activating mutations, as well as by ER-independent signaling pathways. The breast ER antagonist lasofoxifene, alone or combined with palbociclib, elicited antitumor activities in a xenograft model of ER + metastatic breast cancer (mBC) harboring ESR1 mutations. The current study investigated the activity of LAS in a letrozole-resistant breast tumor model that does not have ESR1 mutations. METHODS: Letrozole-resistant, MCF7 LTLT cells tagged with luciferase-GFP were injected into the mammary duct inguinal glands of NSG mice (MIND model; 6 mice/group). Mice were randomized to vehicle, lasofoxifene ± palbociclib, fulvestrant ± palbociclib, or palbociclib alone 2-3 weeks after cell injections. Tumor growth and metastases were monitored with in vivo and ex vivo luminescence imaging, terminal tumor weight measurements, and histological analysis. The experiment was repeated with the same design and 8-9 mice in each treatment group. RESULTS: Western blot analysis showed that the MCF7 LTLT cells had lower ERα and higher HER2 expressions compared with normal MCF7 cells. Lasofoxifene ± palbociclib, but not fulvestrant, significantly reduced primary tumor growth versus vehicle as assessed by in vivo imaging of tumors at study ends. Percent tumor area in excised mammary glands was significantly lower for lasofoxifene plus palbociclib versus vehicle. Ki67 staining showed decreased overall tumor cell proliferation with lasofoxifene ± palbociclib. The lasofoxifene + palbociclib combination was also associated with significantly fewer bone metastases compared with vehicle. Similar results were observed in the repeat experiment. CONCLUSIONS: In a mouse model of letrozole-resistant breast cancer with no ESR1 mutations, reduced levels of ERα, and overexpression of HER2, lasofoxifene alone or combined with palbociclib inhibited primary tumor growth more effectively than fulvestrant. Lasofoxifene plus palbociclib also reduced bone metastases. These results suggest that lasofoxifene alone or combined with a CDK4/6 inhibitor may offer benefits to patients who have ER-low and HER2-positive, AI-resistant breast cancer, independent of ESR1 mutations.

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.

Effects of Letrozole Treatment and Vitamin C Supplementation on Morphology, Endoplasmic Reticulum Stress, Programmed Cell Death, and Oxidative Stress in the Small Intestine of Adult Male Rats.

Estrogens are hormones that play an important role in the digestive tract, including in men. Letrozole is an inhibitor of cytochrome P450 aromatase, an enzyme converting androgens to estrogens. The use of letrozole may cause oxidative stress and endoplasmic reticulum stress in the cells. Factors modulating cellular stress may include vitamin C. The purpose of this study was to examine whether letrozole and/or vitamin C supplementation can affect the morphology of the small intestine, the parameters of endoplasmic reticulum stress, programmed cell death markers, and oxidative damage. Three-month-old male rats were divided into four groups and treated with the following: (I) CTRL-water; (II) CTRL+C-L-ascorbic acid; (III) LET-letrozole; and (IV) LET+C-letrozole + L-ascorbic acid. The morphometrical measurements included epithelial thickness, crypt and lumen area, crypt perimeter, nuclei number in the crypt, and the cell size of crypts. The expression levels of PERK, caspase-3, and catalase were determined. Significant differences in the morphometrical measurements and immunoexpression were observed. This may indicate that chronic treatment with letrozole can affect morphology and induce ER stress, oxidative stress, and programmed cell death in the epithelial cells of the small intestine of adult male rats. Vitamin C supplementation exerts an effect on some parameters of the molecular processes.

Application of small animal ultrasound imaging technology for identification of polycystic ovary syndrome in a mouse model.

BACKGROUND AND AIMS: Polycystic ovary syndrome (PCOS) is a hormonal disorder common among women of reproductive age, characterized by irregular menstrual periods, elevated levels of androgens, and polycystic ovaries, leading to various symptoms and complications such as infertility, metabolic issues, and increased risk of diabetes and heart disease. This study aimed to compare traditional histological methods and ultrasound imaging for consistency in identifying PCOS in a mouse model. The shortest time to construct the PCOS model using letrozole was determined. METHODS: Female C57/BL mice were randomly divided into three groups: Group A received normal saline and a regular diet; Group B received 1 mg/kg/day of letrozole with a regular diet; and Group C received 1 mg/kg/day of letrozole with a high-fat diet. All mice were administered letrozole by intragastric gavage daily for five weeks. The traditional identification method included measuring body weight, examining vaginal smears, monitoring the estrous cycle, measuring serum androgen levels, and performing H&E staining of ovarian tissues. The PCOS model was evaluated using ultrasound imaging to identify and monitor follicles. The significance of the difference between the traditional identification method and the ultrasonic method was calculated using the nonparametric McNemar test, and consistency between the two methods was assessed with the kappa-coefficient test. On this basis, the ultrasound imaging technology was used to monitor the model-making process for 2, 3 and 4 weeks, and to monitor the parameters of the ovary and follicles to judge the shortest time that gavage letrozole caused the appearance of vesicular follicles in the mouse ovary. RESULTS: The traditional identification method showed no PCOS phenotype in group A mice, while groups B and C showed multiple ovarian cystic follicles, indicating successful model induction. The ultrasound imaging results were consistent with the traditional method, showing no PCOS in group A and multiple cystic follicles in groups B and C. The McNemar test revealed no significant difference between the traditional and ultrasonic identification methods. The kappa-coefficient test assessed consistency, yielding a value of 0.903, indicating strong agreement between the methods. The ovarian area, diameter, and the number and diameter of cystic follicles were not significantly changed at two weeks in the letrozole group compared with the control group. At three weeks, there were significant increases in the number and in the diameter of vesicular follicles compared with control cells. At four weeks, the number and diameter, the maximum cross-sectional area and diameter of the ovary were significantly increased compared with the control group. CONCLUSIONS: The ultrasound and traditional methods provide consistent results for identifying PCOS in a mouse model. Construction of the PCOS model by letrozole gavage takes at least three weeks.

Superior suppression of serum estrogens during neoadjuvant breast cancer treatment with letrozole compared to exemestane.

PURPOSE: The aromatase inhibitor letrozole and the aromatase inactivator exemestane are two of the most pivotal cancer drugs used for endocrine treatment of ER-positive breast cancer in all phases of the disease. Although both drugs inhibit CYP19 (aromatase) and have been used for decades, a direct head-to-head, intra-patient-cross-over comparison of their ability to decrease estrogen synthesis in vivo is still lacking. METHODS: Postmenopausal breast cancer patients suitable for neoadjuvant endocrine therapy were randomized to receive either letrozole (2.5 mg o.d.) or exemestane (25 mg o.d.) for an initial treatment period, followed by a second treatment period on the alternative drug (intra-patient cross-over study design). Serum levels of estrone (E1), estradiol (E2), letrozole, exemestane, and 17-hydroxyexemestane were quantified simultaneously using a novel, ultrasensitive LC-MS/MS method established in our laboratory. RESULTS: Complete sets of serum samples (baseline and during treatment with letrozole or exemestane) were available from 79 patients, including 40 patients starting with letrozole (cohort 1) and 39 with exemestane (cohort 2). Mean serum estrone and estradiol levels in cohort 1 were 174 pmol/L and 46.4 pmol/L at baseline, respectively. Treatment with letrozole suppressed serum E1 and E2 to a mean value of 0.2 pmol/L and 0.4 pmol/L (P < 0.001). After the cross-over to exemestane, mean serum levels of E1 and E2 increased to 1.4 pmol/L and 0.7 pmol/L, respectively. In cohort 2, baseline mean serum levels of E1 and E2 were 159 and 32.5 pmol/L, respectively. Treatment with exemestane decreased these values to 1.8 pmol/L for E1 and 0.6 pmol/L for E2 (P < 0.001). Following cross-over to letrozole, mean serum levels of E1 and E2 were significantly further reduced to 0.1 pmol/L and 0.4 pmol/L, respectively. Serum drug levels were monitored in all patients throughout the entire treatment and confirmed adherence to the protocol and drug concentrations within the therapeutic range for all patients. Additionally, Ki-67 values decreased significantly during treatment with both aromatase inhibitors, showing a trend toward a stronger suppression in obese women. CONCLUSION: To the best of our knowledge, we present here for the first time a comprehensive and direct head-to-head, intra-patient-cross-over comparison of the aromatase inhibitor letrozole and the aromatase inactivator exemestane concerning their ability to suppress serum estrogen levels in vivo. All in all, our results clearly demonstrate that letrozole therapy results in a more profound suppression of serum E1 and E2 levels compared to exemestane.

Sodium oligomannate's amelioration of reproductive and metabolic phenotypes in a letrozole-induced PCOS-like mouse model depends on the gut microbiome†.

It has been well established that there is a connection between polycystic ovary syndrome pathology and gut microbiome dysbiosis. A marine-derived oligosaccharide, GV-971, has been reported to alter gut microbiota and alleviate Aß amyloidosis. In this study, the effects of GV-971 on polycystic ovary syndrome-like mice were explored. Mice were randomly assigned into four groups: control, letrozole, letrozole + GV-971, and control + GV-971. Glucose metabolism in polycystic ovary syndrome-like mice was ameliorated by GV-971, while the reproductive endocrine disorder of polycystic ovary syndrome-like mice was partially reversed. The messenger ribonucleic acid levels of steroidogenic enzymes in ovaries of polycystic ovary syndrome-like mice were improved. GV-971 restored the fertility of polycystic ovary syndrome-like mice and significantly increase the number of litters. Furthermore, GV-971 treatment effectively mitigated abnormal bile acid metabolism. Notably, after GV-971 intervention, gut microbiota alpha-diversity was considerably raised and the relative abundance of Firmicutes was reduced. In conclusion, the hyperinsulinemia and hyperandrogenemia of polycystic ovary syndrome-like mice were alleviated by GV-971 intervention, which was associated with mitigating bile acid metabolism and modulating gut microbiota.

Apelin receptor modulation mitigates letrozole-induced polycystic ovarian pathogenesis in mice.

AIMS: Polycystic ovarian syndrome (PCOS) is one of the most common (about 5-20%) reproductive disorders in women of reproductive age; it is characterized by polycystic ovaries, hyperandrogenism, and oligo/ anovulation. The levels and expression of ovarian adipokines are deregulated in the PCOS. Apelin is an adipokine that acts through its receptor (APJ) and is known to express in the various tissues including the ovary. It has also been suggested that apelin and APJ could be targeted as therapeutic adjuncts for the management of PCOS. However, no study has been conducted on the management of PCOS by targeting the apelin system. Thus, we aimed to evaluate its impact on combating PCOS-associated ovarian pathogenesis. METHODS: The current work employed a letrozole-induced-hyperandrogenism PCOS-like mice model to investigate the effects of apelin13 and APJ, antagonist ML221. The PCOS model was induced by oral administration of letrozole (1 mg/kg) for 21 days. A total of four experimental groups were made, control, PCOS control, PCOS + aplein13, and PCOS + ML221. The treatment of apelin13 and ML221 was given from day 22 for two weeks. KEY FINDINGS: The letrozole-induced PCOS-like features such as hyperandrogenism, cystic follicle, decreased corpus luteum, elevated levels of LH/FSH ratio, and up-regulation of ovarian AR expression were ameliorated by apelin13 and ML221 treatment. However, the PCOS-augmented oxidative stress and apoptosis were suppressed by apelin 13 treatments only. ML221 treatment still showed elevated oxidative stress and stimulated apoptosis as reflected by decreased antioxidant enzymes and increased active caspase3 and Bax expression. The expression of ERs was elevated in all groups except control. Furthermore, the PCOS model showed elevated expression of APJ and apelin13 treatment down-regulated its own receptor. Overall, observing the ovarian histology, corpus luteum formation, and decreased androgen levels by both apelin13 and ML221 showed ameliorative effects on the cystic ovary. SIGNIFICANCE: Despite the similar morphological observation of ovarian histology, apelin13 and ML221 exhibited opposite effects on oxidative stress and apoptosis. Therefore, apelin13 (which down-regulates APJ) and ML221 (an APJ antagonist) may have suppressed APJ signalling, which would account for our findings on the mitigation of polycystic ovarian syndrome. In conclusion, both apelin13 and ML221 mediated mitigation have different mechanisms, which need further investigation.

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.

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.

Oocyte in-vitro maturation primed with letrozole-HCG versus FSH-HCG in women with oocyte maturation abnormalities: a retrospective study.

RESEARCH QUESTION: Are there differences between in-vitro maturation (IVM) primed with letrozole-human chorionic gonadotrophin (HCG) and IVM primed with FSH-HCG in women with oocyte maturation abnormalities (OMAs), defined as at least two failed IVF cycles where immature oocytes were retrieved? DESIGN: This retrospective study was conducted at a private fertility clinic from January 2009 to April 2023. The final analysis included 75 women in Group 1 (IVM primed with FSH-HCG) and 52 women in Group 2 (IVM primed with letrozole-HCG). RESULTS: A significantly higher median number of oocytes was obtained in Group 1 compared with Group 2 {9 [interquartile range (IQR) 1-5] versus 5 (IQR 1-18); P < 0.001}. However, no differences in oocyte maturation stage at collection were found between the groups (P > 0.05). At the end of IVM, Group 1 had 73/666 mature oocytes and Group 2 had 106/322 mature oocytes, and the median metaphase II oocyte rate per patient was higher in Group 2 [33.3% (IQR 66.7-100.0%) versus 0.0% (IQR 0.0-22.2%); P < 0.001]. Moreover, Group 2 demonstrated a higher median fertilization rate [66.7% (IQR 50.0-100.0%) versus 50.0% (IQR 0.0-66.7%); P = 0.027]. Group 2 had a higher proportion of Grade 2 embryos (58.5% versus 6.3%), and Group 1 had a higher proportion of Grade 3 embryos (93.8% vs 24.4%; P < 0.001). Notably, all pregnancies obtained in the study were in Group 2 (5 versus 0; P = 0.042). CONCLUSIONS: IVM primed with letrozole-HCG in women with prior failed IVF cycles due to OMAs may result in mature oocytes, clinical pregnancies and live births. The effectiveness of letrozole priming for the subtypes of OMAs needs further investigation, with studies including greater numbers of cases.

Comparing letrozole and mifepristone pre-treatment in medical management of first trimester missed miscarriage: a prospective open-label non-inferiority randomised controlled trial.

OBJECTIVE: To investigate whether letrozole pre-treatment is non-inferior to mifepristone pre-treatment, followed by misoprostol, for complete evacuation in the medical treatment of first-trimester missed miscarriage. DESIGN: Prospective open-label non-inferiority randomised controlled trial. SETTING: A university-affiliated hospital. POPULATION: We recruited 294 women diagnosed with first-trimester missed miscarriage who opted for medical treatment. METHODS: Participants were randomly assigned to: (i) the mifepristone group, who received 200 mg mifepristone orally followed 24-48 h later by 800 µg misoprostol vaginally; or (ii) the letrozole group, who received 10 mg letrozole orally once-a-day for 3 days, followed by 800 µg misoprostol vaginally on the third (i.e. last) day of letrozole administration. MAIN OUTCOME MEASURES: The primary outcome was the rate of complete evacuation without surgical intervention at 42 days post-treatment. Secondary outcomes included induction-to-expulsion interval, adverse effects, women's satisfaction, number of doses of misoprostol required, duration of vaginal bleeding, pain score on the day of misoprostol administration and other adverse events. RESULTS: The complete evacuation rates were 97.8% (95% CI 95.1%-100%) and 97.2% (95% CI 94.4%-99.9%) in the letrozole and mifepristone groups, respectively (p ≤ 0.001 for non-inferiority). The mean induction-to-tissue expulsion interval in the letrozole group was longer compared with the mifepristone group (15.4 vs 9.0 h) (p = 0.03). The letrozole group had less heavy post-treatment bleeding and an earlier return of menses. There were no statistically significant differences in the number of doses of misoprostol required, the duration of vaginal bleeding, the pain score on the day of misoprostol administration and the rate of other adverse events between the two groups. The majority of the women (91.2% and 93.9% in the letrozole and mifepristone groups, respectively) were satisfied with their treatment option. CONCLUSIONS: Letrozole is non-inferior to mifepristone as a pre-treatment, followed by misoprostol, for the medical treatment of first-trimester missed miscarriage.

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].

Patuletin Ameliorates Inflammation and Letrozole-Induced Polycystic Ovarian Syndrome in Rats.

Concerns about inflammation-related issues affecting female reproductive health are growing. Chronic low-grade inflammation in women with polycystic ovarian syndrome (PCOS) affects follicular growth, ovulation, and androgen production. The present investigation aimed to elucidate the efficacy of flavonoid patuletin in ameliorating the letrozole-induced PCOS and associated inflammation in rats. Female Wistar rats (32 days old) were divided into five groups (n = 12): Group I, control; Group II, vehicle control; Group III, letrozole oral (1 mg/kg) for 28 days; Group IV and Group V treatment groups, patuletin i.p. (25 mg/kg) and clomiphene citrate + metformin i.p. (50 mg/kg + 300 mg/kg), respectively. Leterozole-induced PCOS and ovarian inflammation were ameliorated by patuletin, as reflected in the improved histopathology, prevention of cyst formation, significant upregulation of growth factors such as growth differentiation factor 9 (GDF-9) and bone morphogenetic protein-15 (BMP-15) expression, and a decrease in the pro-inflammatory cytokines TNF-α, IL-6, and COX-2. Additionally, the plasma levels of reproductive hormones were restored. Upregulation of FSH-R, PR, and CYP19a1, along with downregulation of ERα, LHR, CYP17a1, CYP11a1 and HSDß17a1, showed the regulation of gonadotropin receptors and steroid biosynthesis genes in ovarian tissues. Patuletin demonstrated a promising protective approach against the biological model of PCOS by increasing the inflammation in ovarian tissues with consequent regulation of growth factors, enzymes, and hormones, and might be used as adjuvant therapy in the treatment of problems related to female reproductive health.

Ameliorative potential of rosmarinic acid in a rat model of polycystic ovary syndrome: Targeting MCP-1 and VEGF: A histological, immunohistochemical, and biochemical study.

Polycystic ovary syndrome (PCOS) is a multidisciplinary endocrinopathy that affects women of reproductive age. It is characterized by menstrual complications, hyperandrogenism, insulin resistance, and cardiovascular issues. The current research investigated the efficacy of rosmarinic acid in letrozole-induced PCOS in adult female rats as well as the potential underlying molecular mechanisms. Forty female rats were divided into the control group, the rosmarinic acid group (50 mg/kg per orally, po) for 21 days, PCOS group; PCOS was induced by administration of letrozole (1 mg/kg po) for 21 days, and rosmarinic acid-PCOS group, received rosmarinic acid after PCOS induction. PCOS resulted in a marked elevation in both serum luteinizing hormone (LH) and testosterone levels and LH/follicle-stimulating hormone ratio with a marked reduction in serum estradiol and progesterone levels. A marked rise in tumor necrosis factor-α (TNF-α), interleukin-1ß, monocyte chemotactic protein-1, and vascular endothelial growth factor (messenger RNA) in the ovarian tissue was reported. The histological analysis displayed multiple cystic follicles in the ovarian cortex with markedly thin granulosa cell layer, vacuolated granulosa and theca cell layers, and desquamated granulosa cells. Upregulation in the immune expression of TNF-α and caspase-3 was demonstrated in the ovarian cortex. Interestingly, rosmarinic acid ameliorated the biochemical and histopathological changes. In conclusion, rosmarinic acid ameliorates letrozole-induced PCOS through its anti-inflammatory and antiangiogenesis effects.

Adding Letrozole to Growth Hormone and Gonadotropin-Releasing Hormone Analog Increases Height in Girls With Short Stature: A Hospital Record-Based Retrospective Study.

OBJECTIVE: There have been rare data on letrozole for height improvement in girls. This study aimed to clarify the efficacy and safety of combination therapy with recombinant human growth hormone (rhGH), GnRHa, and letrozole in improving the height of girls with short stature and advanced bone age. METHODS: This was a hospital record-based retrospective study. Follow-up was conducted on girls with short stature who received treatment with rhGH, GnRHa, and letrozole in our hospital. The treatment group included a total of 29 participants. Before treatment, the mean age of the patients was 11.17 years, and the mean treatment duration was 17.31 months. The control group consisted of 29 short-statured girls who received rhGH/GnRHa treatment, with the mean age and treatment duration of 12.43 years and 16.59 months, respectively. RESULTS: The predicted adult heights (PAHs) before and after treatment were 155.38 and 161.32 cm (P < .001). The ΔPAH in the treatment group was 4 cm higher than that in the control group (5.85 vs 1.82 cm, P < .001). Significant differences were noted in the height standard deviation scores of bone age (P < .001) and chronological age (P = .003) before and after treatment. There was an increasing body mass index during therapy (P = .039). The height gain was 8.71 ± 4.46 cm, and the growth rate was 6.78 ± 3.84 cm per year. CONCLUSION: Combined treatment with GH, GnRHa, and letrozole can enhance the adult height and PAH in short-statured girls, and no significant side effects have been reported.

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.

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.

Is combined letrozole and clomiphene superior to either as monotherapy: a systemic review and meta-analysis based on clinical trials.

OBJECTIVE: This research was conducted to assess the therapeutic advantage of combined letrozole and clomiphene citrate versus monotherapy for polycystic ovarian syndrome (PCOS) patients. STUDY DESIGN: Five databases were searched using the search string: (letrozole and clomiphene) AND (clomiphene OR clomiphene citrate OR CC) AND (letrozole OR LE) AND (ovulation induc* OR fertility induc* OR fertility preserv*) AND (polycystic ovarian syndrome OR PCOS). All statistical analyses were conducted in Review Manager 5.4.1. Random effect-effect model was used to pool risk ratio (RR), mean difference (MD), and odds ratio (OR) and their corresponding 95% confidence interval (CI). Moreover, qualitative analysis was conducted to qualitatively analyze ovulation, secondary outcomes, and cycle characteristics. RESULTS: One clinical trial and three randomized clinical trials (RCTs) were used in the study. Two studies were used in a quantitative analysis showing that combination was superior for ovulation induction (RR = 1.86 [1.37, 2.53]; p < 0.0001; I2 = 0%), but the number of follicles ≥15 mm was significantly associated with the combination (MD = 0.40[0.14, 0.66]; p = 0.002; I2 = 0%). On subgroup analysis, only hot flushes were significantly associated with the combination (RR = 2.67[1.12, 6.36]; p = 0.03; I2 = 0%). The meta-analysis of two studies reported a significantly higher ovulation rate and number of dominant follicles in the combination therapy group compared with the LE alone arm but no significant difference in pregnancy rate, endometrial thickness, and adverse events. CONCLUSION: Our study demonstrates a significant effect of the combination on ovulation induction. The combination yielded a better chance of conception and viable pregnancy. Further studies are needed to determine the live birth rate. HighlightsCombined Letrozole and Clomiphene is superior to either of these drugs alone for ovulation induction in PCOS.Our results conclude that the combination results in better ovulation, cycle characteristics, and secondary changes.Only the incidence of hot flushes as an adverse effect is increasingly reported in combination.

Letrozole-induced reversible acute heart failure.

INTRODUCTION: Letrozole is an aromatase inhibitor (AI), which suppresses plasma estrogen levels by inhibiting the aromatase enzyme, that causes the conversion of androgens to estrogen in peripheral tissues. There is very few information in the literature regarding the development of acute heart failure after AI use. We would like to report a case of a patient who was started letrozole for hormonal treatment and developed acute heart failure due to this. CASE REPORT: Fifty-seven-year-old woman with hormone positive breast cancer was operated after neoadjuvant chemotherapy and received radiotherapy. Letrozole treatment was initiated after radiotherapy and the patient presented to the emergency department after two weeks with cough and dyspnea. Ejection fraction decreased to 20% and acute heart failure developed. MANAGEMENT AND OUTCOME: Letrozole treatment was stopped. Afterwards, improvement in the patient's cardiac functions was observed. Letrozole-induced heart failure was thought to be reversible. DISCUSSION: Letrozole is one of the most commonly used HT in the treatment of hormone positive breast cancer. It may rarely cause cardiac side effects. It is very important to make patients aware of these issues and to be consulted by cardiology in case of possible cardiac symptoms.

Letrozole cotreatment progestin-primed ovarian stimulation in women undergoing controlled ovarian stimulation for in vitro fertilization.

AIM: To investigate the impact of letrozole cotreatment progestin-primed ovarian stimulation (PPOS) (Le PPOS) in controlled ovarian stimulation (COS) and the pregnancy outcomes in frozen-thawed embryo transfer cycles. METHODS: This retrospective cohort study included women who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI). A total of 2575 cycles were included (1675 in the Le PPOS group and 900 in the PPOS group). The primary outcome was the clinical pregnancy rates. The secondary outcome was the live birth rates. RESULTS: In this study, propensity score matching (PSM) was performed to create a perfect match of 379 patients in each group. After matching, the numbers of oocytes retrieved, mature oocytes, fertilization, and clinical pregnancy rates were more favorable in the Le PPOS group than in the PPOS group (all p < 0.05). The multivariable analysis showed that the clinical pregnancy rate was higher in the Le PPOS than in the PPOS group (odds ratio = 1.46, 95% confidence interval: 1.05-2.04, p = 0.024) after adjusting for potentially confounding factors (age, anti-Müllerian hormone levels, antral follicular count, the type of embryo transferred, number of transferred embryos, body mass index, and follicular stimulating hormone and estradiol levels on starting day). CONCLUSIONS: This retrospective study with a limited sample size suggests that the Le PPOS protocol might be an alternative to the PPOS protocol in women undergoing COS and could lead to better pregnancy outcomes. The results should be confirmed using a formal randomized controlled trial.