A real-world study of the effects of endocrine therapy on liver function in breast cancer / 中华外科杂志

Objective: To compare the effect of different endocrine therapy drugs on liver function in patients with early breast cancer. Methods: A retrospective cohort study was conducted to include 4 318 patients with early breast cancer who received adjuvant endocrine therapy in Department of Breast Surgery, Peking Union Medical College Hospital from January 1, 2013 to December 31, 2021. All the patients were female, aged (51.2±11.3) years (range: 20 to 87 years), including 1 182 patients in the anastrozole group, 592 patients in the letrozole group, 332 patients in the exemestane group, and 2 212 patients in the toremifene group. The mixed effect model was used to analyze and compare the liver function levels of patients at baseline, 6, 12, 18, 24, 36, 48, 60 months of medication, and 1 year after drug withdrawal among the three aromatase inhibitors (anastrozole, letrozole, exemestane) and toremifene. Results: ALT and AST of the 4 groups were significantly higher than the baseline level at 6 months (all P<0.01), and there were no significant differences in total bilirubin, direct bilirubin and AST levels among all groups one year after drug withdrawal (P: 0.538, 0.718, 0.061, respectively). There was no significant difference in the effect of all groups on AST levels (F=2.474, P=0.061), and in the effect of three aromatase inhibitors (anastrozole, letrozole, and exemestane) on ALT levels (anastrozole vs. letrozole, P=0.182; anastrozole vs. exemestane, P=0.535; letrozole vs. exemestane, P=0.862). Anastrozole and letrozole had significantly higher effects on ALT levels than toremifene (P<0.01, P=0.009). The proportion of abnormal liver function in each group increased significantly at 6 months compared with baseline, and then the proportion showed a decreasing trend over time. Conclusions: Three aromatase inhibitors (anastrozole, letrozole, and exemestane) and toremifene can significantly increase the level of ALT and AST in patients with breast cancer, and the levels can gradually recover to the baseline after 1 year of drug withdrawal. The effect of non-steroidal aromatase inhibitors (anastrozole, letrozole) on ALT levels is greater than toremifene.

Investigation of teratogenic effects of letrozole on fetal bone development / Investigación de los efectos teratogénicos de letrozol en el desarrollo óseo fetal

SUMMARY: Letrozole is mainly used for the treatment of unexplained infertility, breast cancer and polycystic ovarian syndrome, with secondary use in ovarian stimulation. In cases of unexpected or unknown pregnancy during the use of letrozole, letrozole may cause a teratogenic effect on the fetus. In this reason, in this study, we aimed to determine the effect of letrozole on fetal bone development. In this study, 32 pregnant Wistar albino rats were used. The rats were divided into four groups: Control (saline) and high; 0.3 mg/kg, medium; 0.03 mg/kg, low; 0.003 mg/ kg letrozole. Saline and letrozole were administered in 100 mL solutions by intraperitonaly from day 11 to day 15 of pregnancy. The skeletal system development of fetuses was examined with double skeletal staining, immunohistochemical staining methods and mineral density scanning electron microscopy. A total of 100 fetuses from female rats, 25 in each group, were included in the study. As a result of that, ossification rates were observed to decrease depending on the dose of letrozole in the forelimb limb (scapula, humerus, radius, ulna) and hindlimb (femur, tibia, fibula) limb bones. As a result of the statistical analysis, a statistically significant decrease was found in the ossification rates of all bones between the control group and low, medium, high letrozole groups (p<0.001). Exposure to letrozole during pregnancy adversely affected ossification and bone growth. However, the teratogenic effects of letrozole are unclear. Therefore, it needs to be investigated more extensively.

RESUMEN: Letrozol se usa principalmente para el tratamiento de la infertilidad inexplicable, el cáncer de mama y el síndrome de ovario poliquístico, con estimulación ovárica de uso secundario. En casos de embarazo inesperado o desconocido durante el uso de letrozol, puede causar un efecto teratogénico en el feto. Por esta razón, en este estudio, nuestro objetivo fue determinar el efecto de letrozol en el desarrollo óseo fetal. Se utilizaron 32 ratas albinas Wistar preñadas las cuales se distribuyeron en cuatro grupos: Control (solución salina) y alta; 0,3 mg/kg, medio; 0,03 mg/kg, bajo; 0,003 mg/kg de letrozol. Se administró solución salina y letrozol en soluciones de 100 mL por vía intraperitoneal desde el día 11 hasta el día 15 de la preñez. El desarrollo del sistema esquelético de los fetos se examinó con tinción esquelética doble, métodos de tinción inmunohistoquímica y microscopía electrónica de barrido de densidad mineral. Se incluyeron en el estudio un total de 100 fetos de ratas hembra, 25 en cada grupo. Como resultado, se observó que las tasas de osificación disminuían dependiendo de la dosis de letrozol en los huesos de los miembros torácicos (escápula, húmero, radio, ulna) y de las miembros pélvicos (fémur, tibia, fíbula). Se encontró una disminución estadísticamente significativa en las tasas de osificación de todos los huesos entre el grupo control y los grupos de letrozol bajo, medio y alto (p<0,001). La exposición a letrozol durante la preñez afectó negativamente la osificación y el crecimiento óseo. Sin embargo, los efectos teratogénicos del letrozol no están claros por lo que debe ser investigado más extensamente.

Atualizações na terapêutica farmacológica para infertilidade na mulher diagnosticada com síndrome de ovários policísticos: revisão de literatura / Updates on pharmacological treatments for infertility in women diagnosed with polycystic ovary syndrome: a literature review

Objetivo: Abordar atualizações referentes à terapia medicamentosa para indução da ovulação nas mulheres diagnosticadas com síndrome dos ovários policísticos (SOP). Métodos: Revisão de literatura por meio de levantamento bibliográfico do período de 1975 a 2021, nas bases eletrônicas PubMed, SciELO e MedLine, complementado pela Diretriz Internacional Baseada em Evidências para a Avaliação e Manejo da SOP de 2018 e pelo manual da Febrasgo para SOP. Sete descritores que atendessem à finalidade da pesquisa foram utilizados. Resultados: A literatura aponta atualmente algumas drogas como opção na terapêutica para a indução de ovulação, como metformina, letrozol e citrato de clomifeno, evidenciando que o uso de letrozol isolado e em associação com a metformina apresentaram melhores taxas de ovulação, 71,5% e 75,4%, respectivamente. Conclusão: O uso do letrozol isolado ou combinado com a metformina apresentou os melhores resultados nas taxas de gravidez e ovulação, todavia o tratamento para indução ovulatória deve ser individualizado.(AU)

Objective: To address updates of medicinal therapy for ovulation induction in women diagnosed with polycystic ovary syndrome (PCOS). Methods: Reviewing Literature through a bibliographic survey from 1975 to 2021, on the electronic databases PubMed, SciELO and MedLine, complemented by the International Evidence-Based Guideline for the Evaluation and Management of PCOS 2018 and the Febrasgo guide for PCOS. Seven descriptors that matched to the purpose of the research were applied. Results: Some drugs are currently indicated in the literature as an option for ovulation induction therapy, such as: metformin, letrozole and clomiphene citrate, showing that the use of letrozole alone and in association with metformin had better ovulation rates, 71.5% and 75.4%, respectively. Conclusion: The use of letrozole alone or combined with metformin showed the best results in pregnancy and ovulation rates, however, treatment for ovulatory induction must be individualized.(AU)

The morphology of paca (Cuniculus paca) testis with high dose of letrozole an aromatase inhibitor / La morfología del testículo de paca (Cuniculus paca) con altas dosis de letrozol, un inhibidor de la aromatasa

SUMMARY: The study reported the influence of the high and acute dose of Letrozole on the testis morphology in paca (Cuniculus paca), an aromatase inhibitor that reduces the endogenous estrogen, the essential hormone for spermatogenesis. Morphological changes were observed in seminiferous epithelium with germ cells with apoptotic characteristics and presence of vacuoles and nuclei in pycnose.

RESUMEN: El objetivo de este estudio fue analizar la influencia de una dosis alta de Letrozol en la morfología de los testículos de la paca (Cuniculus paca), un inhibidor de la aromatasa que reduce el estrógeno endógeno, la hormona esencial para la espermatogénesis. Se observaron cambios morfológicos en el epitelio seminífero con células germinales con características apoptóticas y la presencia de vacuolas y núcleos en picnosis.

Changes of tyrosine phosphorylation in liver and kidney of polycystic ovarian rats induced by letrozole / Cambios de fosforilación de tirosina en hígado y riñón de ratas ováricas poliquísticas inducidas por letrozol

Letrozole (Letro) is a drug commonly used for breast cancer treatment since it can decrease estrogen level. In experimental animal, the Letro has been used to induce the polycystic ovarian syndrome (PCOS) model. Tyrosine phosphorylation (TyrPho) is an essential process in various biological functions both normal and abnormal conditions especially reproduction. Although some side effects of Letro are reported, the alterations of TyrPho responsible for liver and kidney functions have never been demonstrated. In this study, the blood serum, liver, and kidney of control and PCOS rats induced with Letro (orally, 1 mg/ KgBW) for consecutive 21 days were used to determine the serum biochemical components and to investigate the TyrPho expression using western blot analysis. Histopathology of such tissues was observed by Masson's trichrome staining. The results showed that Letro did not affect histological structures but significantly increased the serum levels of urea nitrogen, cholesterol, triglyceride, HDL, LDL, ALT, AST, and alkaline phosphatase. Additionally, the TyrPho protein expressions of 32 and 27 kDas in liver and of 55 and 43 kDas in kidney were increased while of a kidney 26 kDa was decreased as compared to those of control. In conclusion, this recent study indicated that the changes of TyrPho proteins in liver and kidney induced with Letro associated with their functions by alteration of serum biochemical levels.

El letrozol (Letro) es un medicamento utilizado comúnmente para el tratamiento del cáncer de mama, debido a que puede disminuir el nivel de estrógeno. En animales de experimentación, el Letro se ha utilizado para inducir el modelo de síndrome de ovario poliquístico (PCOS). La fosforilación de tirosina (TyrPho) es un proceso esencial en diversas funciones biológicas, tanto en condiciones normales como anormales, especialmente en la reproducción. A pesar de informes que indican algunos efectos secundarios de Letro, no se han demostrado las alteraciones de TyrPho responsables de las funciones hepáticas y renales. En este estudio, el suero sanguíneo, el hígado y el riñón control y las ratas PCOS inducidas con Letro (por vía oral, 1 mg / KgBW) durante 21 días consecutivos se usaron para determinar los componentes bioquímicos del suero y para investigar la expresión de TyrPho usando análisis de transferencia Western. La histopatología de los tejidos se observó mediante la tinción tricrómica de Masson. Los resultados mostraron que Letro no afectó las estructuras histológicas, pero aumentó significativamente los niveles séricos de urea, colesterol, triglicéridos, HDL, LDL, ALT, AST y fosfatasa alcalina. Además, las expresiones de la proteína TyrPho de 32 y 27 kDas en el hígado y de 55 y 43 kDas en el riñón aumentaron mientras que en un riñón disminuyeron 26 kDa en comparación con el control. En conclusión, este estudio indicó que los cambios de las proteínas TyrPho en el hígado y los riñones inducidos con Letro se asociaron con sus funciones mediante la alteración de los niveles bioquímicos en suero.

Efficacy and safety of letrozole in treatment of male children with disorders of sex development / 浙江大学学报·医学版

OBJECTIVE@#To investigate the efficacy and safety of aromatase inhibitor letrozole in treatment of male children with disorders of sex development (DSD).@*METHODS@#Clinical data of 12 male DSD children with a mean age of 14.6±2.5 years admitted to Peking Union Medical College Hospital from January 2014 to January 2016 were retrospectively analyzed. The patients were treated with letrozole (1.25-2.5 mg, once a day) for 3 months or longer, and followed up for 0.5-2.5 years. Clinical manifestation and laboratory test findings were documented, and the efficacy and safety were evaluated.@*RESULTS@#After half-year treatment, the blood luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels of patients increased (all < 0.05), and estrogen levels decreased from baseline ( < 0.05). After 1 year of treatment, the blood testosterone level was significantly higher ( < 0.05); the LH and FSH levels tended to increase and the estrogen level tended to decrease, but there was no significant statistical difference ( >0.05). Semen was routinely detected in 8 patients, and sperms were detected in semen of 3 patients with hypospadias. There were no significant changes in biochemical results after treatment, and no significant adverse event was observed during the treatment.@*CONCLUSIONS@#Letrozole can effectively increase testosterone levels in patients with disorders of sex development and promote spermatogenesis, it has no significant adverse effects in short-term administration.

Efficacy of letrozole in treatment of male adolescents with idiopathic short stature / 浙江大学学报·医学版

To evaluate the efficacy and safety of aromatase inhibitor letrozole in treatment of male adolescents with idiopathic short stature (ISS). Seventy five boys with height less than 2 standard deviation (SD) below the mean who had entered puberty were enrolled in our study from 2004 to 2017, in the Pediatric Department of the First Affiliated Hospital, Sun Yat-Sen University. Among 75 patients, 28 in letrozole group received letrozole and spironolactone, 30 in gonadotrophin releasing hormone analogue (GnRHa) group received GnRHa injection and 17 had no intervention. Height velocity (HV), increment of bone age/chronological age (ΔBA/ΔCA), the final adult height (FAH) were compared among groups and the safety of letrozole treatment was evaluated. HV maintained faster during letrozole treatment when compared with other groups. HV during GnRHa treatment showed slightly decline in the first 6 months, but decreased remarkably after 6 months, and was significantly lower than that in letrozole group ( < 0.05). The maturation of BA slowed down in both letrozole and GnRHa groups. But the ΔBA/ΔCA in letrozole group during the first and the second year of treatment were significantly higher (0.67±0.09, 0.50±0.15, respectively) when compared with GnRHa group (0.59±0.16, 0.44±0.13, respectively) ( =2.78 and 2.20, all < 0.05). FAH in letrozole group and GnRHa group were (170±4) cm and (170±6)cm, there was no significant differences between the two groups ( >0.05), and both were higher than that in no intervention group (162±4 cm, < 0.01). After 6 months of letrozole treatment, testicular volumes and serum testerone levels increased; 39.2% (11/28) boys had clinical manifestations of hyperandrogenemia, and 82.1% (23/28) boys had decreased serum high-density lipoprotein (HDL) levels. Serum levels of HDL and testerone returned normal and the hyperandrogenemia disappeared after the cessation of letrozole treatment. No significant changes in serum triglyceride, serum low-density lipoprotein (LDL), fating serum levels of insulin and glucose, HOMA-IR were observed. No abnormal liver function, myalgia, scoliosis or aggravations of scoliosis was found. Long term letrozole therapy during puberty in boys with ISS can delay bone maturation without significant decrease of linear growth, and thus can improve the final adult height. No severe adverse reactions were found.

Efficacy and safety of letrozole in treatment of McCune-Albright syndrome girls with peripheral precocious puberty / 浙江大学学报·医学版

OBJECTIVE@#To evaluate the efficacy and safety of the third-generation aromatase inhibitor letrozole in the treatment of McCune-Albright syndrome (MAS) girls with peripheral precocious puberty.@*METHODS@#Twenty-one MAS girls with peripheral precocious puberty treated in Pediatrics Department of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from March 2012 to June 2017 were enrolled in the study. Patients presented with repeated vaginal bleeding, premature breast enlargement, café-au-lait spots or dysplasia of bone fibers, and low levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH); and the congenital adrenal hyperplasia, estrogen-producing tumors, and exogenous estrogen intake were excluded. Letrozole were administrated at a dose of 0.5-2 mg·m ·d for 6 to 12 months. The patients were observed for changes in breast staging, vaginal bleeding, sex hormone levels, liver function and bone age changes, and changes in uterine and ovarian volume.@*RESULTS@#After treatment, bone age/chronological age (BA/CA)was decreased from 1.23±0.30 to 1.11±0.18 ( < 0.01); the predicted adult height (PAH) increased from (156.2±5.9)cm to (158.4±2.1)cm after treatment ( < 0.05); the vaginal bleeding was reduced and the estradiol level decreased, while the teststosterone level and the uterus showed no significant increase, and no adverse reactions such as ovarian torsion and abnormal liver function were observed.@*CONCLUSIONS@#Precocious puberty is one of the most common endocrine manifestations in MAS. Our findings suggest that letrozole may be an effective and safe therapy to precocious puberty in girls with McCune-Albright Syndrome.

Efficacy of letrozole in treatment of children with congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency / 浙江大学学报·医学版

OBJECTIVE@#To assess the efficacy of letrozole in treatment of children with congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency (21-OHD).@*METHODS@#Twenty eight children, including 19 boys and 9 girls aged 4-10y, with CAH due to 21-OHD were enrolled in the study. At the first six months of study, all children received conventional treatment with hydrocortisone or fludrocortisone, then letrozole was added to original regimen. The height velocity (HV), difference between bone age and chronological age (BA-CA), height standard diviation score based on bone age (HtSDS ), predicted adult height (PAH), Tanner phase, sex hormone, and possible adverse reaction were evaluated and compared between those before and after letrozole treatment.@*RESULTS@#After 6 months of letrozole treatment, there was significant deceleration of HV, but it would recover soon. There was significant increase of HtSDS after 12 months of letrozole treatment ( < 0.05 or < 0.01), and significant changes in BA-CA after 18 months of letrozole treatment ( < 0.05). PAH of female children was significantly increased during letrozole treatment ( < 0.05), whereas PAH of male children was significantly increased 18 months after letrozole treatment ( < 0.05). Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were significantly increased, but did not meet the diagnostic criteria of central precocious puberty. Estradiol was significantly decreased ( < 0.01), but no changes in testosterone level was observed. During 24 months letrozole treatment, no hirsutism, severe acne, headache, bone pain, obesity, hypertension, rash and other adverse reactions were observed.@*CONCLUSIONS@#Letrozole can delay bone maturation and improve PAH, which can be used with conventional treatment for children with CAH due to 21-OHD, especially for those with high BA and low PAH.

Clinical effect of letrozole in treatment of idiopathic short stature in adolescent boys / 中国当代儿科杂志

OBJECTIVE@#To evaluate the therapeutic effect and safety of letrozole in the treatment of adolescent boys with idiopathic short stature (ISS).@*METHODS@#A retrospective analysis was performed for the clinical data of 16 adolescent boys with ISS who had a bone age of ≥14 years. Among these boys, 8 were initially treated with recombinant human growth hormone (rhGH), followed by rhGH combined with letrozole during a bone age of 14-15.5 years. The other 8 boys were initially treated with rhGH combined with letrozole since their bone age was ≥14 years at diagnosis. Of the 16 boys, 16 were treated for not less than 6 months, 12 were treated for not less than 1 year, and 5 were treated for not less than 1.5 years. The increase in bone age, predicted adult height (PAH), final adult height, sex hormones, and adverse reactions after treatment were analyzed.@*RESULTS@#After 6 months, 1 year, and 1.5 years of treatment, median bone age was increased by 0 year, 0.5 year, and 0.5 year respectively, which was significantly lower than the increase in age (P0.05).@*CONCLUSIONS@#In adolescent boys with ISS and a high bone age, rhGH combined with letrozole can safely and effectively delay the increase in bone age and improve PAH and final adult height, with little adverse effect.

The use of aromatase inhibitors in boys with short stature: what to know before prescribing?

ABSTRACT Aromatase is a cytochrome P450 enzyme (CYP19A1 isoform) able to catalyze the conversion of androgens to estrogens. The aromatase gene mutations highlighted the action of estrogen as one of the main regulators of bone maturation and closure of bone plate. The use of aromatase inhibitors (AI) in boys with short stature has showed its capability to improve the predicted final height. Anastrozole (ANZ) and letrozole (LTZ) are nonsteroidal inhibitors able to bind reversibly to the heme group of cytochrome P450. In this review, we describe the pharmacokinetic profile of both drugs, discussing possible drug interactions between ANZ and LTZ with other drugs. AIs are triazolic compounds that can induce or suppress cytochrome P450 enzymes, interfering with metabolism of other compounds. Hydroxilation, N-dealkylation and glucoronidation are involved in the metabolism of AIs. Drug interactions can occur with azole antifungals, such as ketoconazole, by inhibiting CYP3A4 and by reducing the clearance of AIs. Antiepileptic drugs (lamotrigine, phenobarbital, and phenytoin) also inhibit aromatase. Concomitant use of phenobarbital or valproate has a synergistic effect on aromatase inhibition. Therefore, it is important to understand the pharmacokinetics of AIs, recognizing and avoiding possible drug interactions and offering a safer prescription profile of this class of aromatase inhibitors. Arch Endocrinol Metab. 2017;61(3):391-7.

Trombocitopenia inducida por tamoxifeno y letrozol / Thrombocytopenia induced by tamoxifen and letrozole

El tamoxifeno y el letrozol son fármacos muy utilizados en el tratamiento del cáncer de mama. Está descrito que la trombocitopenia (recuento plaquetario inferior a 100.000/mm3) es un efecto secundario raro tras el tratamiento con tamoxifeno. Sin embargo, no es un efecto adverso conocido del letrozol. Presentamos dos casos clínicos en los que tras tratamientos prolongados con estos fármacos nos encontramos con que las pacientes desarrollan trombocitopenia. En ambos casos, este efecto adverso desaparece en pocas semanas tras la retirada del fármaco.

Letrozole and tamoxifen are drugs used in the treatment of breast cancer. It is reported that thrombocytopenia (less than 100,000 / mm3 platelet count) is a rare side effect of tamoxifen. However, it is not a known side effect of letrozole. We present two cases in which after prolonged treatment with these drugs we found that the patients develop thrombocytopenia. In both cases, this adverse effect disappears a few weeks after drugs were stopped.

Effects of compound malt pills on expressions of ERα and ERβ in ovaries of rats with letrozole-induced polycystic ovarian syndrome / 中南大学学报(医学版)

OBJECTIVE@#To explore the effect of compound malt pills (CMP) on polycystic ovarian syndrome (PCOS) rat model induced by letrozole and the underlying mechanisms.
@*METHODS@#To establish a PCOS rat model, 48 female SD rats aged 6 weeks were randomly divided into 6 groups (n=8): A normal group, a model control group, a positive control group, a low-dose CMP group, a middle-dose CMP group, and a high-dose CMP group. Rats were treated for 21 days after the PCOS model was successfully established. Ovarian morphology changes were observed, and the expressions of ERα and ERβ was examined by immunohistochemistry, Western blot and RT-PCR, respectively.
@*RESULTS@#Compared with the normal group, the number of follicular cystic dilatation in the model control group was increased and the granulosa cells were decreased. After the treatment, the number of follicular cystic dilatation was reduced compared with the model control group, but the primordial follicles, corpus luteum and granulosa cells were increased. The expressions of ERα and ERβ in the model control group were significantly decreased (P<0.01), which were increased in the intervention groups (P<0.05 or P<0.01).
@*CONCLUSION@#CMP may play a role in the treatment of PCOS by regulating the expressions of ERα and ERβ.

GC-MS analysis of Cocus nucifera flower extract and its effects on heterogeneous symptoms of polycystic ovarian disease in female Wistar rats / 中国天然药物

AIM@#To evaluate the effect of Cocus nucifera L. flowers in reducing the major multiple symptoms of letrozole-induced polycystic ovarian disease (PCOD) in female rats.@*METHOD@#Female, virgin Wistar rats were treated with letrozole (1 mg/kg body wt) to induce PCOD, and after 21 days of induction rats were administered orally with 100 and 200 mg·kg(-1) of Cocus nucifera flower aqueous extract, respectively. Estrus cycle and blood sugar were monitored once a week throughout the study. After scarification, various biochemical parameters, such as antioxidant status (superoxide dismutase (SOD) and glutathione reductase (GSH)) of the uterus homogenate, lipid profile (total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL), and triglycerides (TG)) of the serum were determined. Weights of the uterus and ovaries were separately monitored. The characteristics of changes in the ovary were evaluated by histopathological studies.@*RESULTS@#GC-MS analysis of the aqueous extract showed the presence of volatile and pharmacologically active phytoconstituents. C. nucifera flower extract-treated groups showed estrus cyclicity and increased uterus weight which indicates the estrogenic effect. The improved blood sugar level, ideal lipid profile, good antioxidant status, and histopathology results revealed the recovery from poly cystic ovaries.@*CONCLUSION@#The results indicate that C. nucifera flower is a potential medicine for the treatment of PCOD and this study supports the traditional uses of C. nucifera flower.

Effect of letrozole on endometrosis and apoptosis of ectopic endometrial cells in rats / 中南大学学报(医学版)

OBJECTIVE@#To investigate the therapeutic mechanism of letrozole, the third-generation aromatase inhibitor, on endometriotic lesions in a rat model and its effect on the apoptosis of ectopic endometrial cells.@*METHODS@#Endometriosis was induced by autotransplanting pieces of uterus onto the peritoneum in rats. The rats with successful ectopic implants were divided into 2 groups: A letrozole group (n=15) and a control group (n=15). The volume, appearance, and histopathology of ectopic implant were determined before and after the treatment. Expression of P450arom, COX-2, bcl-2, and bax in the ectopic implant was detected by immunohistochemistry and RT-PCR in the 2 groups.@*RESULTS@#The volume of ectopic implant in the letrozole group was significantly reduced compared with the control group (P<0.05). The protein and mRNA levels of P450arom and COX-2 in the ectopic implant were significantly decreased in the letrozole group compared with the control group (P<0.05). There was a positive correlation between the expression of P450arom and the expression of COX-2 (r=0.943, P<0.001; r=0.913, P<0.001). The protein and mRNA expression of bcl-2 was significantly decreased (P<0.05), and the bax protein and mRNA expression was significantly increased (P<0.05) in the ectopic implant with an increased bax/bcl-2 ratio in the letrozole group compared with the control group (P<0.05).@*CONCLUSION@#Letrozole can obviously reduce the size of ectopic implant through decreasing P450arom and COX-2 expression, suppressing the secretion of estrogen, inhibiting the proliferation, and inducing the apoptosis of ectopic implants.

Clinical effect of letrozole on the ovulation induction in endometrial preparation for frozen-thawed embryo transfer / 中南大学学报(医学版)

OBJECTIVE@#To evaluate the clinical effect of letrozole (LE) alone on the ovulation induction in endometrial preparation for frozen-thawed embryo transfer (FET).@*METHODS@#Totally 253 FET cycles were analyzed by case control study from October 2010 to June 2011. We divided ovulation disorders or menstrual disorders divided into 2 groups: a LE group on ovulation induction cycle (n=85), and a hormone replacement therapy (HRT) cycle group (n=84). Meanwhile those who ovulated normally were included in a natural cycle group (n=84). Demographics and clinical parameters of reproductive correlation of all patients were observed among these groups.@*RESULTS@#The average clinical pregnancy rate of the LE group was higher than that of HRT cycle group (54.1% vs 44.04%; P0.05). The estradiol level on human chorionic gonadotrophin (HCG) administration day in the natural cycle group [(341.19±113.14) pg/mL] was higher than that of the LE group [(279.70±127.80) pg/mL] (P0.05).@*CONCLUSION@#Ovulation induction with LE alone for endometrial preparation is superior to HRT cycle in FET and has similar clinical process and outcome to those of the natural cycle. It can be applied in endometrial preparation for FET effectively for those with anovulation or menstrual disorder.

Comparison of three protocols for Controlled Ovarian Hyperstimulation (COH) for clomiphene citrate poor responders

Objective: To compare the efficacy of Letrozole and Gonadotropin, given alone or in combination, in controlled ovarian hyperstimulation in Clomiphene citrate poor responders. Study Design: Prospective, non-randomized observational study on Clomiphene citrate poor responders at the St. Luke's Medical Center setting from January to July 2006. Results: Letrozole and gonadotropins, whether given alone or in combination, have similar clinical outcomes in terms of endometrial thickness during ovulation and the number of dominant follicles developed. The use of gonadotropins results in 100% ovulation rate, similar to results when Letrozole is used as an adjunct. Letrozole significantly reduces the dose of gonadotropin required to develop a mature follicle. Conclusion: Since the use of Letrozole and gonadotropins for ovarian hyperstimulation had similar results, Letrozole has the advantage of reduced cost and greater patient acceptance. It may be used alone or in conjunction with gonadotropins for poor responders to Clomiphene citrate.

randomized trial of metformin-letrozole versus metformin-clomiphene citrate in patients with polycysytic ovary syndrome resistant to clomiphene

To compare the effects of the combination of aromatase inhibitor Letrozole [2.5 mg] and metformin vs. clomiphene citrate [CC: 100 mg] and metformin in clomiphene resistant PCO women. In a prospective randomized trial, a total of 120 cycles in 60 women with clomiphene resistant polycystic ovary syndrome were studied. Patients were randomized into treatment with 2.5 mg of Letrozole daily [29 patients, 53 cycles] or 100 mg of CC daily [30 patients, 67 cycles]. Number of mature follicles, endometrial thickness, estradiol level, pregnancy rate, and miscarriage rate were measured. The mean age, BMI, infertility duration, ovulation rate and the number of mature follicles [>18 mm] in both groups of patients were similar. Total and per follicle estradiol concentrations were significantly lower in the Letrozole group than in the CC group on the day of HCG administration [1664.63 +/- 1350 vs. 981.35 +/- 648 and 783.38 +/- 251 vs. 447.60 +/- 133.36 picomol/L], and the endometrial thickness was significantly higher [0.82 +/- 0.1 vs. 0.55 +/- 0.28 cm]. No difference was found in metformin side effects between both groups. There was no significant difference in pregnancy rate between Letrozole and CC groups [10 cases or 34.5% vs. 5 pregnancies or 16.67% respectively]. Two miscarriages of the 5 pregnancies [40.0%] occurred in the CC group with no abortion in Letrozole group. In comparison to the CC group term pregnancies were also significantly higher in the Letrozole group [10 cases or 34.5% vs. 3 pregnancies or 10.00% respectively]. In women with clomiphene resistant polycysytic ovary syndrome, the combination of Letrozole and metformin is associated with higher pregnancy, and lower miscarriage rates in comparison to CC and metformin