Role of an estrogen-upregulated 64.0-kDa uterine fluid glycoprotein in improving fertility in women

N-glycoproteomic analysis of human follicular fluid during natural and stimulated cycles in patients undergoing in vitro fertilization

OBJECTIVE

Hyperstimulation methods are broadly used for in vitro fertilization (IVF) in patients with infertility; however, the side effects associated with these therapies, such as ovarian hyperstimulation syndrome (OHSS), have not been well studied. N-glycoproteomes are subproteomes used for the remote sensing of ovarian stimulation in follicular growth. Glycoproteomic variation in human follicular fluid (hFF) has not been evaluated. In this study, we aimed to identify and quantify the glycoproteomes and N-glycoproteins (N-GPs) in natural and stimulated hFF using label-free nano-liquid chromatography/electrospray ionization-quad time-of-flight mass spectrometry.

METHODS

For profiling of the total proteome and glycoproteome, pooled protein samples from natural and stimulated hFF samples were selectively isolated using hydrazide chemistry to obtain the total proteomes and glycoproteomes. N-GPs were validated by the consensus sequence N-X-S/T (92.2% specificity for the N-glycomotif at p<0.05). All data were compared between natural versus hyperstimulated hFF samples.

RESULTS

We detected 41 and 44 N-GPs in the natural and stimulated hFF samples, respectively. Importantly, we identified 11 N-GPs with greater than two-fold upregulation in stimulated hFF samples compared to natural hFF samples. We also validated the novel N-GPs thyroxine-binding globulin, vitamin D-binding protein, and complement proteins C3 and C9.

CONCLUSION

We identified and classified N-GPs in hFF to improve our understanding of follicular physiology in patients requiring assisted reproduction. Our results provided important insights into the prevention of hyperstimulation side effects, such as OHSS.

Overt leptin response to controlled ovarian hyperstimulation negatively correlates with pregnancy outcome in in vitro fertilization--embryo transfer cycle

CONTEXT

A critical body mass of adipose tissue is essential for the normal development of female reproductive functions. Leptin, an adipocyte-derived hormone encoded by the 'Ob' gene has been proposed as a peripheral signal indicating the adequacy of nutritional status for reproductive functions. It is reported as a direct regulator of gametogenic and steroidogenic potential of ovary. Though leptin is widely present in reproductive tissues, its relationship to reproductive hormones is still poorly understood.

AIMS

Present investigation attempts to explore ovarian response to secretory profile of leptin and its impact on pregnancy outcome in women undergoing controlled ovarian hyperstimulation for in vitro fertilization and embryo transfer (IVF-ET).

SETTINGS AND DESIGN

Patients enrolled for IVF-ET underwent pituitary-ovarian suppression by 'Long Protocol' GnRH-agonist downregulation followed by ovarian stimulation.

MATERIALS AND METHODS

Sera were procured at different phases of IVF-ET for the assay of estradiol, progesterone, human chorionic gonadotropin, and for leptin. Ovarian follicular fluids were also assayed for leptin. Luteinized granulosa cells were cultured in vitro to evaluate their steroidogenic potential.

STATISTICAL ANALYSIS USED

Statistical analyses were done by student's t-test, ANOVA, and Chi-square tests as applicable. All results were expressed as Mean ± SE. P values < 0.05 were considered significant.

RESULTS

Positive correlation was observed between serum and ovarian follicular fluid leptin. A negative correlation was noted between the serum leptin levels and endometrial thickness.

CONCLUSIONS

Elevated leptin response may exert adverse impacts on pregnancy success during IVF-ET possibly by modulating uterine receptivity.