Role of thyroid stimulating hormone in the maintenance and functioning of the human corpus luteum

PURPOSE

To evaluate the impact of high thyroid stimulating hormone (TSH) levels on human granulosa-luteal (hGL) cells.

METHODS

hGL cells were isolated from follicular aspirates derived from patients undergoing IVF treatment without any thyroid disorder (serum TSH 0.5-2 mU/L). Cells were cultured at 37 °C in DMEM, supplemented with 5% FBS. The cells were treated with 1 nM LH and increasing concentrations of TSH. At the end of culture, conditioned medium and cells were collected to analyze progesterone production, cell viability, and mRNA levels of genes involved in the steroidogenesis process. Human ovarian tissues were analyzed for TSH receptor (TSHR) expression by IHC.

RESULTS

The expression of TSHR was detected in human corpus luteum by IHC and in hGL by RT-PCR. In hGL cells, TSH treatment did not modulate progesterone production nor the expression of steroidogenic genes, such as p450scc and HSD3b 1/2. However, TSH induced a dose-dependent increase in cell death. Finally, TSH did not affect LH-induced p450scc and HSD3b1/2 expression while LH partially reverted TSH negative effect on cell death in hGL.

CONCLUSIONS

Elevated TSH levels in hypothyroid women may be associated with impaired CL functioning and maintenance. These findings open a new line of research for the importance of the treatment of women with thyroid dysfunction that could contribute to the onset of infertility.

Circulating irisin levels in functional hypothalamic amenorrhea: a new bone damage index? A pilot study

PURPOSE

Patients with functional hypothalamic amenorrhea (FHA) could commonly have bone damage, often preceded by metabolic alterations due to a relative energy deficit state. To date, there are no markers capable of predicting osteopenia before it is manifested on DXA. Irisin is a myokine that promotes the differentiation of osteoblastic cells and appears to be inversely correlated with the incidence of bone fragility and fractures in postmenopausal women. The aim of this study was to measure irisin levels in FHA patients and to correlate it with bone density parameters.

METHODS

Thirty-two patients with FHA and 19 matched controls underwent the same clinical and laboratory evaluation.

RESULTS

Irisin and body mass index (BMI) were significantly lower in the case group than in healthy controls (2.03 ± 0.12 vs. 2.42 ± 0.09 p < 0.05 and 19.43 ± 2.26 vs. 22.72 ± 0.67 p < 0.05, respectively). Additionally, total body mass density (BMD g/cm²) was significantly lower in the case group than in the healthy controls (1.09 ± 0.08 vs. 1.14 ± 0.05, p < 0.05), without signs of osteopenia.

CONCLUSIONS

The FHA group showed lower irisin levels associated with significantly reduced BMD parameters that did not reach the severity of osteopenia. Therefore, we could speculate that irisin could predict DXA results in assessing modifications of body composition parameters. Future research is warranted to study these parameters in a larger population to confirm our results, so that irisin could be used as a predictor and screening method for bone deprivation. Furthermore, irisin is strictly related to energy metabolism and could be an indirect marker of nutritional status in FHA patients, identifying earlier states of energy deficit.

"Hormone of darkness" and human reproductive process: direct regulatory role of melatonin in human corpus luteum

PURPOSE

To investigate the possible role of melatonin on human luteal cell function.

METHODS

Corpora lutea were obtained from normally menstruating women (25-38 years old) in the midluteal phase (days 5-6 from ovulation) at the time of surgery for non-endocrine gynecologic diseases. The protocol was approved by the institutional review board of Università Cattolica del Sacro Cuore in Rome and all patients provided written informed consent. The corpora lutea were dated on the basis of the presumptive day of ovulation (day 0) , determined by urinary luteinizing hormone (LH) peak, ultrasound detection of corpus luteum or disappearance of the dominant follicle, and a rise in the plasma P concentration. ELISA or EIA kit and immunohistochemistry were performed.

RESULTS

Melatonin was able to increase progesterone release and to influence the balance between luteotrophic and luteolityc factors. In addition, melatonin expression and MT2 receptor were detected, confirming the direct action of this indoleamine on CL.

CONCLUSIONS

Melatonin may play an intriguing role in direct regulation of CL function and in establishing and maintaining of initial pregnancy. In conclusion, melatonin could become a relevant medication for improving ovarian and luteal function and in the early stages of pregnancy, opening new opportunities for the management of several ovarian-luteal and pregnancy diseases.

Increased fibulin-1 plasma levels in polycystic ovary syndrome (PCOS) patients: possible contribution to the link between PCOS and cardiovascular risk

PURPOSE

To investigate a possible relation between fibulin-1 plasma levels and PCOS.

DESIGN

ELISA quantitative determination of human fibulin-1.

METHODS

50 women with PCOS and 40 control patients who attended the Unit of Human Reproductive Pathophysiology, Università Cattolica del Sacro Cuore, Rome, were enrolled. Ultrasonographic pelvic examinations, hormonal profile assays, oral tolerance test OGTT, lipid profile and ELISA quantitative determination of human fibulin-1 were performed.

RESULTS

Fibulin-1 levels were found to be statistically significantly higher in PCOS patients than in matched control women. No statistically significant positive correlation was found between fibulin-1 and AUCi, HOMA-IR, total cholesterol, LDL, AMH, androstenedione and FAI, whereas a statistically significant positive correlation was found between fibulin-1 and 17OHP (p = 0.016) in the PCOS group. However, multivariable linear regression analysis showed that 17 OH P did not independently predict fibulin-1 levels (p = 0.089).

CONCLUSIONS

Our data could contribute to explain the hypothesized increased cardiovascular risk and vascular damage in patients with PCOS. A better understanding of the cellular and molecular mechanisms involved in cardiometabolic disorders associated with PCOS is mandatory to identify new therapeutic strategies to eventually prevent the progression of cardiovascular diseases in these patients.