Anita Mylius Pimentel

Transvaginal ultrasound ovarian diathermy: sheep as an experimental model

BackgroundSome techniques of transvaginal ovarian drilling have been previously described. Nevertheless a monopolar transvaginal ovarian cauterization, that use the expertise and safety of transvaginal puncture for oocyte captation seems to be an easier and feasible approach. The aim of this study was to develop a minimally invasive ovarian cauterization technique under transvaginal ultrasound control, and to evaluate the safety of the transvaginal ovarian monopolar cauterization, female sheep at reproductive age were used as an experimental model.FindingsAn experimental study was performed in a university research center. Seventeen female sheep (15 Corriedale e 2 Suffolk) in reproductive age were submitted to transvaginal ovarian cauterization with a monopolar Valleylab Force 2 electrocautery. Macroscopic and microscopic lesions were assessed. Ovarian size were 1.31 cm2 ± 0,43 (Corriedale) and 3.41 cm2 ± 0,64 (Suffolk). From 30 ovaries from Corriedale sheep punctured, only 3 were cauterized, presenting macroscopic and typical microscopic lesion. In the Suffolk sheep group, only one ovary was cauterized. No lesion could be found in the needle path.ConclusionsThis is the first experimental animal model described for ovarian cauterization needle guided by transvaginal ultrasound. The sheep does not seem to be the ideal animal model to study this technique. Another animal model, whose ovaries are better identified by transvaginal ultrasound should be sought for this technique, theoretically less invasive, before it could be offered safely to women with polycystic ovary syndrome.

Human Granulosa Cells: Insulin and Insulin-Like Growth Factor-1 Receptors and Aromatase Expression Modulation by Metformin

Background/Aim: Granulosa cells are the source of the most important ovarian steroids. Even in patients without significant improvement in metabolic parameters, metformin has apparently an important effect on the ovary. The aim of this study was to evaluate gene and protein expression of an insulin receptor (IR), insulin-like growth factor-1 (IGF1) receptor (IGF1R) and aromatase in granulosa cells treated with metformin and insulin. Methods: Luteinized granulosa cells were collected from 27 patients during in vitro fertilization procedures. Cells were isolated, stored in culture for 24 h and divided into four groups: control; metformin for 30 min, and metformin for 30 min plus insulin for 30 or 60 min. Results: IR and IGF1R mRNA expression was significantly enhanced by metformin but was not affected by insulin. Aromatase mRNA expression was significantly reduced in metformin-incubated cells following stimulation with insulin for 30 min. No statistical differences were found in IGF1R and aromatase protein expression, and IR expression was not detected. Conclusion: A direct effect of metformin on the gene expression of IGF1R, IR and aromatase was observed. Further studies should investigate the role of IGF1R, IR and aromatase in ovarian physiology for a better understanding of the effect of metformin.

Impact of tubal ligation on ovarian reserve as measured by anti-Müllerian hormone levels: a prospective cohort study.

BACKGROUND Tubal ligation (TL) is considered a very efficient contraceptive method. However, some patients complain of a variety of postoperative symptoms. The objective of this study was to investigate whether ovarian reserve may change after tubal ligation. STUDY DESIGN This was a prospective cohort study of 80 fertile women who underwent TL. Ovarian reserve was evaluated by measuring pre- and postoperative (1 year after surgery) serum anti-Müllerian hormone (AMH) levels and transvaginal antral follicular count (AFC). Potential confounding factors were age, body mass index (BMI), smoking, surgical technique and prior contraceptive methods. The Wilcoxon test was used to compare pre- and postoperative (12 months) AMH and AFC, and simple and multiple linear regression were used to evaluate confounding factors. RESULTS Fifty-two patients completed the study protocol. The median AMH level was 1.43 ng/mL (interquartile range 0.63-2.62) preoperatively and 1.30 ng/mL (interquartile range 0.53-2.85) after 12 months (p=.23). The mean AFC was 8.0 (interquartile range 5.0-14.0) and 11.0 (interquartile range 7.0-15.0) before and after TL, respectively (p=.12). These differences were not statistically significant. Use of a hormonal contraceptive method prior to TL was significantly associated with a postoperative increase in AMH. CONCLUSIONS This study suggests that ovarian reserve is not altered by TL.

Developmental potential of in vitro or in vivo matured oocytes

This study compared the embryological features of mature and immature oocytes (different stages) collected from stimulated cycles of in vitro fertilization (IVF). Immature oocytes were identified, classified as PI (prophase I - germinal vesicle, GV) or MI (metaphase I), were matured in vitro and fertilized using the intra-cytoplasmic sperm injection (ICSI) technique. Fertilization potential, cleavage, and subsequent transfer/cryopreservation of the embryos derived from these in vitro matured oocytes were compared with those of in vivo matured oocytes (collected at the MII stage). The characteristics of embryos derived from gametes recovered in the MI and MII stages were similar. The fertilization rate of immature oocytes recovered in PI was significantly lower than that of MII oocytes (P = 0.031), and the cleavage rate of the PI group was also lower than that of the MI (P = 0.004) and MII (P < 0.001) groups. In vitro maturation of MI oocytes is a suitable alternative when immature oocytes are recovered, as their characteristics and development are similar to those of in vivo matured oocytes. Optimization of outcomes for PI oocytes will require development of techniques that can distinguish which of these gametes will mature and fertilize.