This analysis demonstrated that there is a differential representation of these lipids according to their respective groups. In addition, the lipids found are involved in important mechanisms related to endometriosis progress in the ovary. Thus, the metabolomic approach for the study of lipids may be helpful in potential biomarker discovery.

This study identified possible lipid biomarkers in follicular fluid from women with poor ovarian response. These biomarkers indicate pathophysiological pathways and have potential diagnostic applications. An observational case-control study of young women undergoing ovarian stimulation for in-vitro fertilization was conducted. The participants were categorized into a poor ovarian response group and a normal ovarian response to stimulation group. All of the women underwent the same ovarian stimulation protocol, and follicular fluid was collected after ovarian aspiration. Analyses were performed using matrix-assisted laser desorption/ionization mass spectrometry. Principal component analysis and Volcano plots were used to describe follicular fluid classification models based on the lipid profiles. A total of 10 lipids were differentially expressed between the study and control groups. Of these lipid ions, three belonged to the phosphatidylcholine subclass and were present in higher concentrations in the control group. The other seven differential lipids were present in the study group and classified into four lipid subclasses: phosphatidylethanolamines, phosphatidylglycerols, phosphatidylinositols, and diacylglycerols. These distinctive lipids may be involved in hormonal responses and oocyte development processes and may be useful as biomarkers for therapeutic intervention in women with poor ovarian response.

Endometriosis is a chronic gynecological condition that affects 10-32% of women of reproductive age and may lead to infertility. The study of protein profiles in follicular fluid may assist in elucidating possible biomarkers related to this disease. For this, follicular fluid samples were obtained from women with tubal factor or minimal male factor infertility who had pregnancy outcomes after in vitro fertilization (IVF) treatment (control group, n = 10), women with endometriosis (endometriosis group, n = 10), along with the endometrioma from these same patients were included (endometrioma group, n = 10). For proteomic analysis, samples were pooled according to their respective groups and normalized to protein content. Proteins were analyzed by in tandem mass spectrometry (MS(E)) Spectra processing and the ProteinLynx Global Server v.2.5. was used for database searching. Data was submitted to the biological network analysis using Cytoscape 2.8.2 with ClueGO plugin. As a result, 535 proteins were identified among all groups. The control group differentially or uniquely expressed 33 (6%) proteins and equal expression of 98 (18%) proteins was observed in the control and endometriosis groups of which 41 (7%) proteins were further identified and/or quantified. Six (1%) proteins were observed in both the endometriosis and endometrioma groups, but 212 (39%) proteins were exclusively identified and/or quantified in the endometrioma group. There were 9 (1%) proteins observed in both the control and endometrioma groups and there were 139 (25%) proteins common among all three groups. Distinct differences among the protein profiles in the follicular fluid of patients included in this study were found, identifying proteins related to the disease progression and IVF success. Thus, some pathways related to endometriosis are associated with the presence of specific proteins, as well as the absence of others. This study provides a first step to the development of more sensitive diagnostic tests and treatment.

These findings contribute to the understanding of the molecular mechanisms associated with lipid metabolism in the PCOS-related hyper response, and strongly suggest that these lipids may be useful as biomarkers, leading to the development of more individualized treatment for pregnancy outcome.

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