Recurrence-Free Survival after Postoperative Hormone Therapy for Catamenial Pneumothorax.

Background: Catamenial pneumothorax (CP) is a rare form of spontaneous pneumothorax that is linked to endometriosis; thus, it predominantly manifests in women of reproductive age. Considerable research has explored the potential benefits of postoperative hormone therapy following various surgical interventions. This study was performed to examine the clinical implications of postoperative hormone treatment in patients with CP. Methods: The study included patients who underwent surgical intervention for CP between November 2009 and February 2023. These procedures included wedge resection, diaphragm resection, and total pleural coverage. Recurrence-free survival was analyzed using the Kaplan-Meier log-rank test to assess the impact of hormone therapy. Additionally, Cox proportional hazards analysis was employed to identify risk factors associated with postoperative CP recurrence. Results: The study included 41 patients, with a median age of 38.4 years. Among them, 27 individuals received hormone therapy, 8 of whom experienced recurrence during a median follow-up period of 1 year. Patients who received hormone therapy exhibited a lower rate of recurrence than those who did not; however, the difference was not statistically significant, likely due to the small sample size. Side effects of hormone therapy included depression (6.8%), excessive sweating (3.4%), and headache (3.4%). In the analysis of risk factors for postoperative recurrence, diaphragm resection emerged as a protective factor (hazard ratio, 0.16; 95% confidence interval, 0.03-0.77; p=0.022). Conclusion: Hormone treatment combined with surgery did not significantly impact recurrence in patients with CP. The application of diaphragm resection was the sole factor that displayed significance in preventing CP recurrence.

Outcomes of growth hormone treatment in children with Prader-Willi syndrome over a 30-year period: a single tertiary center experience.

OBJECTIVES: Clinical benefits of growth hormone (GH) in Prader-Willi syndrome (PWS) are proven and scoliosis is a known association of both PWS and GH therapy. The aims of this study were to assess GH prescribing practices and growth outcomes over time, the prevalence and predictors of scoliosis in GH-treated PWS children, and the near-final height of GH-treated PWS patients. DESIGN AND METHODS: This is a retrospective, descriptive study evaluating data from all clinic visits of patients aged 0-18 years with PWS, seen through the Children's Hospital at Westmead between March 1992 and May 2022 (n=75). RESULTS: A total of 64 patients were treated with GH (visits = 1,414). In the recent decade, the diagnosis of PWS and GH commencement were made significantly earlier in life. The prevalence of scoliosis was 41 %, in which age was the only significant predictor for scoliosis (odds ratio 1.19: 95 % CI [1.08-1.31; p=0.001]) adjusted for other predictors. In patients with data available at the age 16 years (23/28 treated with GH), those who were GH treated had significantly higher height SDS vs. nontreated group (SDS -0.67 vs. -2.58; p=0.0001) and lower BMI SDS (1.18 vs. 2.37; p<0.001). CONCLUSIONS: Significant improvements in growth and body composition were seen in the GH-treated group vs. non-treated group of children with PWS. There were no significant modifiable clinical predictors of scoliosis in children with PWS, but our findings confirm the high prevalence of scoliosis in GH-treated children with PWS reinforcing the need for close surveillance.

Incidence of High Risk and Malignant Pathological Findings in Transgender and Gender Diverse Individuals Undergoing Gender-Affirming Mastectomy.

BACKGROUND: Concrete, data-driven guidelines for breast cancer screening among the transgender and gender diverse (TGD) population is lacking. The present study evaluates possible associations of gender-affirming hormone therapy (GAHT) on incidental breast pathology findings in trans-masculine patients to inform decision making about breast cancer screening. PATIENTS AND METHODS: This was a retrospective cohort study of patients who had gender-affirming mastectomy or breast reduction at a single center from July 2019 to February 2024. A total of 865 patients met the inclusion criteria. Gender-affirming testosterone therapy and length of exposure were evaluated to seek differences in post-operative pathology findings. RESULTS: The median age at the time of surgery was 27 years [interquartile range (IQR) 21-30]. Most participants identified as female to male (658, 75.6%). A significant portion of the participants (688, 79.2%) were undergoing testosterone therapy at the time of surgery, with the median duration of testosterone use prior to surgery being 14 months (IQR 4-29). High risk or malignant findings were noted in pathology results for 12 of 1730 breasts (0.7%). Ordered logistic regression found that duration of testosterone therapy was not associated with increasing severity of incidental breast pathology. Additionally, patients under 25 years of age were 70% less likely to have any incidental finding on pathological evaluation than older patients [odds ratio (OR) 0.3, p < 0.01, confidence interval (CI) 0.18-0.50]. CONCLUSIONS: The present study found that patients undergoing GAHT should not be screened for breast cancer with increased frequency compared with cis-gender women. Additionally, it may be appropriate for trans women under the age of 25 with normal breast cancer risk to forego pathological breast tissue examination.

Climacteric and fibromyalgia: a review.

Fibromyalgia (FM) and climacteric conditions share common epidemiological and clinical features, with FM symptoms often beginning during menopause. Musculoskeletal pain, arthralgia, myalgia and other symptoms are frequently seen in both conditions. Some research suggests a link between the cessation of sex hormones and FM symptoms. Women with FM tend to experience more severe symptoms after menopause, and the severity of FM symptoms can worsen in women who have had a hysterectomy with or without oophorectomy. Despite these similarities, it is essential to treat FM and climacteric conditions separately and follow established guidelines for management. However, it is also important to recognize that both conditions can coexist in the same patient. It is crucial to note that there is limited evidence supporting the effectiveness of menopausal hormone therapy for primary FM management. Therefore, menopausal hormone therapy should not be recommended for FM unless the patient also has climacteric syndrome.

Gender-affirming hormone therapy for transgender and gender-diverse adults in Australia.

Gender-affirming hormone therapy (GAHT) is used by many transgender and gender-diverse adults to align physical characteristics with their gender identity, reduce gender incongruence and improve psychological functioning. This narrative review provides an overview of the initiation and monitoring of GAHT in an Australian context. Trans individuals treated with testosterone typically receive standard testosterone doses and formulations recommended for cisgender men, whereas those receiving estradiol GAHT are typically treated with estradiol in combination with an anti-androgen in those without orchidectomy. Proactive monitoring and mitigation of cardiovascular risk factors is pertinent in all transgender and gender-diverse adults and bone health is an important consideration in those using estradiol GAHT.

Uterine changes in transgender men receiving testosterone therapy.

OBJECTIVES: Despite regular gender-affirming hormone therapy (GAHT), the presence of uterine bleeding can occur occasionally and cause profound discomfort. This study aimed to evaluate the histologic features and immunohistochemical expression of estrogen (ER), progesterone (PR), and androgen (AR) receptors in the endometrium and myometrium of transgender men receiving testosterone therapy and relate them to clinical and hormonal characteristics. DESIGN: Retrospective cross-sectional study. METHODS: Thirty-four transgender men undergoing GAS were included. Clinical, sociodemographic, and laboratory data as well as anatomopathologic and immunohistochemical findings were evaluated. RESULTS: The participants' mean age was 42.35 (SD,10.00) years, and body mass index was 28.16 (SD,5.52)kg/m2. The mean GAHT duration before surgery was 5.36 (SD,3.24) years. The mean testosterone levels were 814.98 (SD,407.13)ng/dL, and estradiol levels were 55.22 (SD,25.27)pg/mL. The endometrium was atrophic in 61.8%, proliferative 17.6%, and secretory in 20.6%. Immunohistochemical receptor analysis revealed that endometrial epithelial cells expressed ER (90%) and PR (80%), with a lower expression of AR (30%). In stromal tissue, the median ER, PR, and AR expression was lower than that in the epithelium (60%, 70%, and 25%, respectively). The myometrium showed high expression of PR (90%) and ER (70%), with the highest expression of AR (65%) being localized to this region. CONCLUSIONS: In the present study, GAHT induced an atrophic condition of the endometrium in two-thirds of the transgender men, with a limited AR expression in the endometrial region. The present results suggest that testosterone based GAHT for a mean of 5 years is safe in transgender men achieving amenorrhea.

Prognostic impact of selection criteria of current adjuvant endocrine therapy trials NATALEE and monarchE in postmenopausal HRpos/HER2neg breast cancer patients treated with upfront letrozole.

BACKGROUND: The monarchE and NATALEE trials demonstrated the benefit of CDK4/6 inhibitor (CDK4/6i) therapy in adjuvant breast cancer (BC) treatment. Patient selection, based on clinical characteristics, delineated those at high (monarchE) and high/intermediate recurrence risk (NATALEE). This study employed a historical patient cohort to describe the proportion and prognosis of patients eligible for adjuvant CDK4/6i trials. METHODS: Between 2009 and 2011, 3529 patients were enrolled in the adjuvant PreFace clinical trial (NCT01908556). Eligibility criteria included postmenopausal patients with hormone receptor-positive (HRpos) BC for whom a five-year upfront therapy with letrozole was indicated. Patients were categorized into prognostic groups according to monarchE and NATALEE inclusion criteria, and their invasive disease-free survival (iDFS) and overall survival (OS) were assessed. RESULTS: Among 2891 HRpos patients, 384 (13.3 %) met the primary monarchE inclusion criteria. The majority (n = 261) qualified due to having ≥ 4 positive lymph nodes. For NATALEE, 915 out of 2886 patients (31.7 %) met the eligibility criteria, with 126 patients (13.7 %) being node-negative. Patients from monarchE with ≥ 4 positive lymph nodes and NATALEE with stage III BC exhibited the poorest prognosis (3-year iDFS rate 0.87). Patients ineligible for the trials demonstrated prognoses similar to the most favorable patient groups within the eligibility criteria. CONCLUSION: Patient populations eligible for monarchE and NATALEE trials differed. Nearly a third of the postmenopausal HRpos population, previously under upfront letrozole treatment, met the NATALEE prognostic eligibility criteria. As certain eligible groups had a prognosis similar to non-eligible patients, it might be interesting to explore additional patient groups for CDK4/6i therapy.

Effectiveness and Safety of Different Estradiol Regimens in Transgender Females: A Randomized Controlled Trial.

Background: A goal of gender-affirming hormone therapy (GAHT) for transgender women is to use estradiol to suppress endogenous production of testosterone. However, the effects of different estradiol regimens and route of administration on testosterone suppression is unknown. This is the first open-label randomized trial comparing different GAHT regimens for optimal estradiol route and dosing. Objective: To evaluate 1 month and 6 months testosterone suppression <50 ng/dL with pulsed (once- or twice-daily sublingual 17-beta estradiol) and continuous (transdermal 17-beta estradiol) GAHT. Methods: This study was conducted at an outpatient adult transgender clinic. Thirty-nine transgender women undergoing initiation of GAHT were randomly assigned to receive either once-daily sublingual, twice-daily sublingual, or transdermal 17-beta estradiol. All participants received spironolactone as an antiandrogen. Doses were titrated at monthly intervals to achieve total testosterone suppression <50 ng/dL. Results: Transdermal 17-beta estradiol resulted in more rapid suppression of total testosterone, lower estrone levels, with no differences in estradiol levels when compared to once-daily and twice-daily sublingual estradiol. Moreover, there was no difference in the mean estradiol dose between the once-daily and twice-daily sublingual 17-beta estradiol group. Conclusion: Continuous exposure with transdermal 17-beta estradiol suppressed testosterone production more effectively and with lower overall estradiol doses relative to once or twice daily sublingual estradiol. Most transgender women achieved cisgender women testosterone levels within 2 months on 1 or 2 0.1 mg/24 hours estradiol patches. Given no difference between once- or twice-daily sublingual estradiol, pulsed 17-beta estradiol likely provides no benefit for testosterone suppression.

Transgender Women With Suppressed Testosterone Display Lower Burden of Coronary Disease Than Matched Cisgender Men.

Context: Cardiovascular disease (CVD) in transgender women (TW) may be affected by gender-affirming hormone therapy (GAHT) and HIV, but few data compare TW on contemporary GAHT to well-matched controls. Objective: We compared CVD burden and biomarker profiles between TW and matched cisgender men (CM). Methods: Adult TW on GAHT (n = 29) were recruited for a cross-sectional study (2018-2020). CM (n = 48) from the former Multicenter AIDS Cohort Study were matched 2:1 to TW on HIV serostatus, age ±5 years, race/ethnicity, BMI category and antiretroviral therapy (ART) type. Cardiac parameters were measured by CT and coronary atherosclerosis by coronary CT angiography; sex hormone and biomarker concentrations were measured centrally from stored samples. Results: Overall, median age was 53 years and BMI 29 kg/m2; 69% were non-white. All participants with HIV (71%) had viral suppression on ART. Only 31% of TW had testosterone suppression (<50 ng/dL, TW-S). Traditional CVD risk factors were similar between groups, except that TW-S had higher BMI than TW with non-suppressed testosterone (TW-T). TW-S had no evidence of non-calcified coronary plaque or advanced coronary stenosis, whereas TW-T and CM had similar burden. TW had lower prevalence of any coronary plaque, calcified plaque and mixed plaque than CM, regardless of testosterone concentrations and HIV serostatus. Estradiol but not testosterone concentrations moderately and negatively correlated with the presence of coronary plaque and stenosis. Small sample size limited statistical power. Conclusion: Older TW with suppressed total testosterone on GAHT had no CT evidence of non-calcified coronary plaque or advanced coronary stenosis. Longitudinal studies to understand relationships between GAHT and CVD risk in TW are needed.

Imaging phenotypic differences in multiple sclerosis: at the crossroads of aging, sex, race, and ethnicity.

Clear sex differences are observed in clinical and imaging phenotypes of multiple sclerosis (MS), which evolve significantly over the age spectrum, and more specifically, during reproductive milestones such as pregnancy and menopause. With neuroimaging being an outcome measure and also a key subclinical biomarker of subsequent clinical phenotype in MS, this comprehensive review aims to provide an overview of sex and hormone differences in structural and functional imaging biomarkers of MS, including lesion burden and location, atrophy, white matter integrity, functional connectivity, and iron distribution. Furthermore, how therapies aimed at altering sex hormones can impact imaging of women and men with MS over the lifespan is discussed. This review also explores the key intersection between age, sex, and race/ethnicity in MS, and how this intersection may affect imaging biomarkers of MS.

A Call for Updates to Hormone Therapy Guidelines for Gender-Diverse Adults Assigned Male at Birth.

Gender-affirming hormone therapy for assigned male at birth (AMAB) individuals with gender incongruence typically consists of estradiol with or without an anti-androgen to achieve physical changes and psychological benefits. However, prescribed hormone regimens vary considerably, and high-quality research in this area is extremely limited. Additional evidence-based research evaluating patient-reported outcome measures (PROMs) is needed to fill current knowledge gaps and create a personalized therapeutic approach for AMAB individuals. This editorial provides a critical description of current treatment options, discusses their variability, reviews some discrepancies in guideline-based dosing recommendations, and recommends areas for further study.

Use of chorionic gonadotropins during lactation to optimize postpartum sow reproductive performance: a review.

Treating lactating sows with chorionic gonadotropins may allow controlling their post-weaning reproductive function, despite the occurrence of anestrous during lactation. This article reviews the potential effectiveness of treatment with both equine and human chorionic gonadotropins (eCG and hCG, respectively) during lactation on the control of estrus expression and ovulation in weaned sows. The use of 1,000 IU hCG at 24 and 48 h postpartum may induce ovulation in the treated sows, but the ovulation rate may be variable. Pregnancy rates may be improved with combined treatment after the second week of lactation with both chorionic gonadotropins: 1,500 IU eCG plus 500 - 1,000 hCG; or 1,000 IU eCG plus 1,000 IU hCG. Treatment with eCG (1,000 - 2,000 IU) at the end of lactation may result in acceptable estrus expression and ovulation rates, although with marginal benefit for pregnancy rates. The subsequent response to treatments with chorionic gonadotropins during lactation is likely influenced by the treatment period, the suckling frequency during lactation, and the boar exposure during the weaning-to-estrus interval. A better understanding of the efficiency of such steroid-free treatments is increasingly relevant due to the constraints of the use of steroid hormones in livestock reproductive management.

Pulsatile gonadotropin-releasing hormone therapy induces spermatogenesis in pituitary stalk interruption syndrome: A case report and review of the literature.

BACKGROUND: Pituitary stalk interruption syndrome (PSIS) is a rare anatomical defect of the pituitary gland falling under the spectrum of holoprosencephaly phenotypes. It is characterized by a deficiency in anterior pituitary hormones, such as growth hormone, gonadotropins, and thyroid hormones. Due to the syndrome's rarity and nonspecific manifestations, there is a lack of standardized treatment strategies. Consequently, early diagnosis through imaging and on-time intervention are crucial for improving patients' outcomes. CASE SUMMARY: A 30-year-old man presented with absent secondary sexual characteristics and azoospermia. Laboratory evaluation revealed a deficiency in gonadotropins, while thyroid function was mostly within normal ranges. Magnetic resonance imaging of the pituitary gland showed pituitary stalk agenesis, hypoplasia of the anterior pituitary, and ectopic posterior pituitary, leading to the diagnosis of PSIS. Initially, the patient underwent 6 mo of gonadotropin therapy without significant changes in hormone levels and secondary sexual characteristics. Pulsatile gonadotropin-releasing hormone therapy was then administered, resulting in the detection of sperm in the semen analysis within 3 mo. After 6 mo, routine semen tests showed normal semen quality. The couple faced challenges in conceiving due to abstinence and underwent three cycles of artificial insemination, which was unsuccessful. They also attempted in vitro fertilization, but unfortunately, the woman experienced a miscarriage 10 wk after the embryo transfer. CONCLUSION: Early detection, accurate diagnosis, and timely treatment are crucial in improving the quality of life and fertility of PSIS patients.

Transgender and Nonbinary Individuals' Perceptions Regarding Gender-Affirming Hormone Therapy and Cardiovascular Health: A Qualitative Study.

BACKGROUND: Transgender and nonbinary individuals face substantial cardiovascular health uncertainties. The use of gender-affirming hormone therapy can be used to achieve one's gender-affirming goals. As self-rated health is an important predictor of health outcomes, an understanding of how this association is perceived by transgender and nonbinary individuals using gender-affirming hormone therapy is required. The objective of this research was to explore transgender and nonbinary individuals' perceptions of cardiovascular health in the context of using gender-affirming hormone therapy. METHODS: In this qualitative study, English-speaking transgender and nonbinary adults using gender-affirming hormone therapy for 3 months or more were recruited from across Canada using purposive and snowball sampling methods. Semistructured interviews were conducted through videoconference to explore transgender and nonbinary individuals' perceptions of the association between gender-affirming hormone therapy and cardiovascular health between May and August 2023. Data were transcribed verbatim, and transcripts were analyzed independently by 3 reviewers using thematic analysis. RESULTS: Twenty-one participants were interviewed (8 transgender women, 9 transgender men, and 3 nonbinary individuals; median [range] age, 27 [20-69] years; 80% White participants). Three main themes were identified: cardiovascular health was not a primary concern in the decision-making process with regard to gender-affirming hormone therapy, the improved well-being associated with gender-affirming hormone therapy was felt to contribute to improved cardiovascular health, and health care provider knowledge and attitude facilitate the transition process. CONCLUSIONS: Gender-affirming hormone therapy in transgender and nonbinary individuals is perceived to improve cardiovascular health. Given the positive associations between care aligned with patient priorities, self-rated health, and health outcomes, these findings should be considered as part of shared decision-making and person-centered care.

'Boy smell': transgender and nonbinary people's experiences of bodily smell.

Although smell is sometimes treated with little regard, it is invested with cultural meaning and conveys a great deal of information, including about gender, sexuality and identity. This article draws on interviews with 11 transgender and nonbinary people who have accessed gender affirming hormone therapy (GAHT), and focuses on how they understand and explain changes in how their own bodies smell. Although it is well documented that GAHT causes changes in skin oiliness, changes in smell are inconsistently documented, and within the medical literature are often commented on only in passing. Taking a discourse analytic approach, the article finds that participants noticed changes in their own smell during hormonal transition, that in many cases this change was understood as significant in some way, and that these changes could be experienced as affirming. Understandings of what changes in bodily smell meant were often derived relationally or socially, although participants' discussion of the experience frequently focused on their own embodiment. Smell seems to form part of a process of (re)identification with the physical self and gender affirmation that can be facilitated by GAHT.

Factors affecting shared decision-making concerning menopausal hormone therapy.

Menopausal hormone therapy (MHT) is an effective treatment for menopause-related symptoms. Menopause management guidelines recommend a personalized approach to menopause care, including MHT use. Decision-making around menopause care is a complex, iterative process influenced by multiple factors framed by perspectives from both women and healthcare providers (HCPs). This narrative review aims to summarize evidence around factors affecting decision-making regarding menopause-related care. For HCPs, the provision of individualized risk estimates is challenging in practice given the number of potential benefits and risks to consider, and the complexity of the data available, especially within time-limited consultations. Women seeking menopause care have the difficult task of making sense of the benefit versus risk profiles to make choices in line with their decisional needs influenced by sociocultural/economic, educational, demographic, and personal characteristics. The press, social media, and influential celebrities also impact the perception of menopause and decision-making around it. Understanding these factors can lead to improved participation in shared decision-making, satisfaction with the decision and decision-making process, adherence to treatment, reduced decisional regret, efficient use of resources, and ultimately long-term satisfaction with care.

Mental Health Diagnoses and Suicidality Among Transgender Youth in Hospital Settings.

Purpose: The purpose of this analysis is to: 1) describe the most common mental health diagnoses in the emergency department (ED) and inpatient hospital settings among transgender and gender diverse (TGD) youth vs. matched controls and 2) evaluate if a gender-affirming hormone therapy (GAHT) or gonadotropin-releasing hormone agonist (GnRHa) prescription decreased the risk of suicidality within these settings. Methods: Using the PEDSnet dataset (years 2009-2019), TGD youth aged 8-18 (n = 3414, with a median age at last visit of 16.2 [14.4, 17.7] years, were propensity-score matched to controls (n = 13,628, age 16.6 [14.2, 18.3] years). Relative risks of the most common mental health diagnoses within ED and inpatient settings were calculated for TGD youth compared with controls. Recurrent time-to-event analysis was used to examine whether GAHT or GnRHa attenuated the risk of suicidality among subsamples of TGD youth. Results: TGD youth had a higher relative risk (95% confidence interval [CI]) of mental health diagnoses and suicidality in the ED (5.46 [4.71-6.33]) and inpatient settings (6.61 [5.28-8.28]) than matched controls. TGD youth prescribed GAHT had a 43.6% lower risk of suicidality (hazard ratio [HR] = 0.564 [95% CI 0.36-0.89]) compared with those never prescribed GAHT during our study period or before GAHT initiation. TGD youth who were prescribed GnRHa therapy had a nonstatistically significant reduction in ED or inpatient suicidality diagnoses compared with those never prescribed GnRHa (HR = 0.79 [0.47-1.31]). Conclusion: Although risk of mental health diagnoses and suicidality in ED and inpatient settings was high among TGD youth, a GAHT prescription was associated with a significant reduction in suicidality risk.

The effect of preoperative hormonal stimulation on the urethral plate; A histologic and histochemical study.

AIM OF THE WORK: Preoperative hormone stimulation (PHS) is used to increase the glans size and may improve the cosmetic appearance after hypospadias surgery. The exact effect of PHS on different penile tissues remains unclear and controversial. Previous studies showed that PHS increased vessel density in the foreskin. However, the effect of PHS on the urethral has never been studied before. In this study we examine the PHS effects on the urethral plate. MATERIALS AND METHODS: Specimens of the urethral plate and the underlying tissue were excised to correct severe chordee in 16 children with proximal and perineal hypospadias with severe chordee in 2 groups. Group A consisted of 8 children received PHS prior to surgery. Group B included 8 children with proximal and perineal hypospadias with severe chordee who did not receive PHS and served as a control group. Specimens were examined blindly using hematoxylin-eosin and elastic van-Gieson stain as well as factor 8 and SMA antibodies. RESULTS: The median age of Group A was 13 (range 10-20) months. The median age of Group B (without prior PHS) was 17 (range 14-29) months (p = 0,03). The median vessel-density in group A (82 vessels per mm2) was significantly higher than in Group B (65 per mm2), (p < 0.05). The median vessel diameter was also significantly higher in Group A (13 µm) than in Group B (11 µm), (p < 0.05). The median epithelial layer thickness in Group A was 110 µm and in Group B 98 µm, but showed no statistical significance (p = 0,16). There was no significant change in dartos fascia layer thickness or androgen receptor expression. There was no visual change in the organization of elastic fibers. CONCLUSION: This study is the first study to document the effect of PHS on the urethral plate in hypospadias with severe chordee. PHS significantly increased the median vessel-density as well as median vessel diameter as compared to a matching control group. The findings of the study may justify PHS administration before the first operation to improve the vascularity and may reduce the severity of chordee.

Reversible Sterilization of Channel Catfish via Overexpression of Glutamic Acid Decarboxylase Gene.

The confinement of transgenic fish is essential to prevent their escape and reproduction in natural ecosystems. Reversible transgenic sterilization is a promising approach to control the reproduction of transgenic fish. Therefore, the present study was conducted to develop a reversibly sterile channel catfish (Ictalurus punctatus) via the transgenic overexpression of the goldfish (Carassius auratus) glutamic acid decarboxylase (GAD) gene driven by the common carp (Cyprinus carpio) ß-actin promoter to disrupt normal gamma-aminobutyric acid (GABA) regulation. Three generations of GAD-transgenic fish were produced. All studied generations showed repressed reproductive performance; however, this was not always statistically significant. In F1, 5.4% of the transgenic fish showed a sexual maturity score ≥ 4 (maximum = 5) at five years of age, which was lower (p = 0.07) than that of the control group (16.8%). In the spawning experiments conducted on F1 transgenic fish at six and nine years of age, 45.5% and 20.0% of fish spawned naturally, representing lower values (p = 0.09 and 0.12, respectively) than the percentages in the sibling control fish of the same age (83.3% and 66.7%, respectively). Four of six pairs of the putative infertile six-year-old fish spawned successfully after luteinizing hormone-releasing hormone analog (LHRHa) therapy. Similar outcomes were noted in the three-year-old F2 fish, with a lower spawning percentage in transgenic fish (20.0%) than in the control (66.7%). In one-year-old F2-generation transgenic fish, the observed mean serum gonadotropin-releasing hormone (GnRH) levels were 9.23 ± 2.49 and 8.14 ± 2.21 ng/mL for the females and males, respectively. In the control fish, the mean levels of GnRH were 11.04 ± 4.06 and 9.03 ± 2.36 ng/mL for the females and males, respectively, which did not differ significantly from the control (p = 0.15 and 0.27 for females and males, respectively). There was no significant difference in the estradiol levels of the female transgenic and non-transgenic fish in the one- and four-year-old F2-generation fish. The four-year-old F2-generation male transgenic fish exhibited significantly (p < 0.05) lower levels of GnRH and testosterone than the control fish. In conclusion, while overexpressing GAD repressed the reproductive abilities of channel catfish, it did not completely sterilize transgenic fish. The sterilization rate might be improved through selection in future generations.