Intra-ovarian roles of activins and inhibins

Functional link between bone morphogenetic proteins and insulin-like peptide 3 signaling in modulating ovarian androgen production

Bone morphogenetic proteins (BMPs) are firmly implicated as intra-ovarian regulators of follicle development and steroidogenesis. Here we report a microarray analysis showing that treatment of cultured bovine theca cells (TC) with BMP6 significantly (>twofold; P < 0.01) up- or down-regulated expression of 445 genes. Insulin-like peptide 3 (INSL3) was the most heavily down-regulated gene (-43-fold) with cytochrome P450, subfamily XVII (CYP17A1) and other key steroidogenic transcripts including steroidogenic acute regulatory protein (STAR), cytochrome P450 family 11, subfamily A1 (CYP11A1) and 3 beta-hydroxysteroid dehydrogenase type 1 (HSD3B1) also down-regulated. BMP6 also reduced expression of nuclear receptor subfamily 5A1 (NR5A1) known to target the promoter regions of the aforementioned genes. Real-time PCR confirmed these findings and also revealed a marked reduction in expression of INSL3 receptor, relaxin/insulin-like family peptide receptor 2 (RXFP2). Secretion of INSL3 protein and androstenedione were also suppressed suggesting a functional link between BMP and INSL3 pathways in controlling androgen synthesis. RNAi-mediated knockdown of INSL3 reduced INSL3 mRNA (75%) and protein (94%) level and elicited a 77% reduction in CYP17A1 mRNA and 83% reduction in androstenedione secretion. Knockdown of RXFP2 also reduced CYP17A1 expression (81%) and androstenedione secretion (88%). Conversely, treatment with exogenous (human) INSL3 increased androstenedione secretion ∼twofold. The CYP17A1 inhibitor abiraterone abolished androgen secretion and reduced expression of both INSL3 and RXFP2. Collectively, these findings indicate a positive autoregulatory role for INSL3 signaling in maintaining thecal androgen production, and visa versa. Moreover, BMP6-induced suppression of thecal androgen synthesis may be mediated, at least in part, by reduced INSL3-RXFP2 signaling.

Expression and localization of inhibitor of differentiation (ID) proteins during tissue and vascular remodelling in the human corpus luteum

Members of the transforming growth factor-β (TGF-β) superfamily are likely to have major roles in the regulation of tissue and vascular remodelling in the corpus luteum (CL). There are four inhibitor-of-differentiation (ID1-4) genes that are regulated by members of the TGF-β superfamily and are involved in the transcriptional regulation of cell growth and differentiation. We studied their expression, localization and regulation in dated human corpora lutea from across the luteal phase (n = 22) and after human chorionic gonadotrophin (hCG) administration in vivo (n = 5), and in luteinized granulosa cells (LGCs), using immunohistochemistry and quantitative RT-PCR. ID1-4 can be localized to multiple cell types in the CL across the luteal phase. Endothelial cell ID3 (P < 0.05) and ID4 (P < 0.05) immunostaining intensities peak at the time of angiogenesis but overall ID1 (P < 0.05) and ID3 (P < 0.05) expression peaks at the time of luteolysis, and luteal ID3 expression is inhibited by hCG in vivo (P < 0.01). In LGC cultures in vitro, hCG had no effect on ID1, down-regulated ID3 (P < 0.001), and up-regulated ID2 (P < 0.001) and ID4 (P < 0.01). Bone morphogenic proteins (BMPs) had no effect on ID4 expression but up-regulated ID1 (P < 0.01 to P < 0.005). BMP up-regulation of ID2 (P < 0.05) was additive to the hCG up-regulation of ID2 expression (P < 0.001), while BMP cancelled out the down regulative effect of hCG on ID3 regulation. As well as documenting regulation patterns specific for ID1, ID2, ID3 and ID4, we have shown that IDs are located and differentially regulated in the human CL, suggesting a role in the transcriptional regulation of luteal cells during tissue and vascular remodelling.

Preservation of ovarian function and fertility despite gonadotoxic chemotherapy

The author aims to review the various strategies and avenues for fertility preservation despite gonadotoxic chemotherapy in young women. The recent increase in the survival of young patients has increased the worldwide attempts toward fertility preservation. The currently utilized methods are sperm cryopreservation and banking in male patients, and cryopreservation of embryos, unfertilized oocytes and ovarian tissue, as well as administration of gonadotropin-releasing hormone agonists (GnRH-a) before and during the gonadotoxic chemotherapy in young female patients. For those patients in whom pelvic irradiation is planned, ovariopexy is suggested. Since none of the suggested methods are ideal and none guarantees future fertility, a combination of several methods may optimize patients' chance of fertility preservation. GnRH-a co-treatment may reduce ovarian damage significantly in female patients treated with gonadotoxic chemotherapy. GnRH-a should be considered for women of reproductive age receiving gonadotoxic chemotherapy in addition to assisted reproduction and cryopreservation of embryos, oocytes and ovarian tissue.

Immunohistochemical localization of inhibin/activin subunits in the wild ground squirrel (Citellus dauricus Brandt) ovary

The intraovarian function of gonadally produced inhibin and activin has been extensively studied in experimental models for decades, yet their presence and function have been rarely reported in wild rodents. With our seasonal breeding model, the wild ground squirrel, we aimed to investigate the possible roles of these peptides in the seasonal folliculogenesis. Immunohistochemical staining and Western blotting have been used to detect the cellular localization and expression patterns of inhibin/activin subunits (α, β(A) and β(B)). In the breeding season ovary, all three subunits were present in granulosa cells, theca cells of antral follicles and interstitial cells, with the strongest immunostaining in granulosa cells. Following ovulation, the corpora lutea become a major site of inhibin/activin synthesis. In the nonbreeding season ovary, inhibin/activin α and β(A) subunits were weakly immunopositive in granulosa cells of early stage follicles, while β(B) subunit was undetectable. The expression level of inhibin/activin subunit proteins were generally higher in the ovaries of the breeding season, and then decreased to a relatively low level during the nonbreeding season. The dynamic expression of inhibin/activin subunits indicated that they might play important paracrine and/or autocrine roles during the seasonal folliculogenesis of the wild ground squirrel.

Activin B is produced early in antral follicular development and suppresses thecal androgen production

Little is known about the role of activin B during folliculogenesis. This study investigated the expression levels of activin/inhibin subunits (βA, βB, and α), steroid enzyme, and gonadotrophin receptors in theca (TC) and granulosa cells (GC) by QPCR and activin A and B and inhibin A protein levels in follicular fluid (FF) of developing sheep follicles during estrus and anestrus. The effect of activin B on androgen production from primary TC cultures in vitro was also assessed. During folliculogenesis, in anestrus and estrus, FF activin B concentrations and thecal and GC activin βB mRNA levels decreased as follicle diameter increased from 1–3 to >6 mm regardless of estrogenic status. Estrogenic preovulatory follicles had reduced concentrations of FF activins B and A, and TC and GCs expressed higher levels of activin βA mRNA at 3–4 mm, and TCs more inhibin α mRNA at >4 mm stages of development compared with nonestrogenic follicles. Activin B decreased androstenedione production from primary TCs in vitro, an effect blocked by inhibin A. Thus, sheep follicles 1–3 mm in diameter contained high FF levels of activin B, which decreased as the follicle size increased, and, like activin A, suppressed thecal androgen production in vitro, an effect blocked by inhibin. Furthermore, the theca of large estrogenic follicles expressed high levels of inhibin α and activin βA mRNA suggesting local thecal derived inhibin A production. This would inhibit the negative effects of thecal activins B and A ensuring maximum androgen production for enhanced estradiol production by the preovulatory follicle(s).

Depression, quality of life and malnutrition-inflammation scores in hemodialysis patients

BACKGROUND

Depression is the most common psychiatric illness in patients with end-stage renal disease (ESRD), and has been associated with increased risk of death, cardiovascular events and hospitalization in a substantial proportion of patients. Impaired quality of life (QoL) has been reported in dialysis patients and is a marker of poor outcome. We aimed to assess the prevalence of depression and QoL status among chronic hemodialysis patients. We explored the relationship between depressive symptoms and poor QoL on the one hand and sociodemographic profile, dialysis adequacy, serum chemistry, malnutrition-inflammation score (MIS) and symptom burden on the other hand.

PATIENTS AND METHODS

60 chronic hemodialysis patients participated in the study between June and August 2007. They were on thrice-weekly dialysis at the Kasr El-Aini Nephrology and Dialysis Center, Cairo University Hospital. Clinical and sociodemographic data were obtained and their case records were reviewed to obtain laboratory results including hemoglobin, urea reduction ratio, serum albumin, calcium, phosphorus, creatinine and total iron-binding capacity. We used the Beck Depression Inventory (BDI) to assess the severity of depression, and the SF-36 questionnaire to assess QoL in the study group. MIS was used to assess the extent of malnutrition and inflammation complex and total symptom burden was evaluated using the dialysis symptom index (DSI).

RESULTS

Mean age was 46.13 +/- 16.55 years, with a range of 22-77 years. 20 patients (33.33%) had a BDI score of >or=15. Two patients (3.33%) had a QoL total score of <50, 8 (13.33%) had scores in the range of 50-60, 30 (50%) had scores in the range of 60-70, 12 (20%) had scores of 70-80, and 8 patients (13.3%) had scores in the range of 80-90. Employment was found to significantly affect BDI scores; all patients with BDI scores >or=15 were unemployed. The mean BDI score of unemployed patients was significantly higher than employed patients (13.03 +/- 6.27 vs. 8.50 +/- 3.51, p = 0.03). Widowed patients had significantly higher BDI and lower F-36 scores compared to single, married and divorced patients (p < 0.05). DSI and MIS showed significant positive correlations with BDI scores (p < 0.05) and significant negative correlations with F-36 scores (p < 0.05).

CONCLUSIONS

Our results showed a high prevalence of depressive symptoms among the study group that was linked to poor QoL, total symptom burden and malnutrition-inflammation complex.