P-570 Prokineticin-1 follicular fluid levels are strongly associated with diminished ovarian reserve and poor ovarian response: A prospective observational study
Authors: Pantos K , Grigoriadis S , Maziotis E , Tomara P , Giannelou P , Tzonis P , Pantou A , Mastorakos G , Simopoulou M , Sfakianoudis K 
Published: June 2022

Abstract

Study question
Are Prokineticin-1 (PROK1) follicular fluid (FF) levels associated with poor ovarian response (POR) as well as with other well-known biomarkers associated with ovarian reserve status?

Summary answer
Poor responders present with increased PROK1 FF levels. Also, PROK1 FF levels are negatively correlated with anti-müllerian hormone (AMH) levels and number of oocytes retrieved.

What is known already
Prokineticin-1 is an angiogenic factor with pleiotropic properties. Considering its role in reproduction, PROK1 mediates significant angiogenic functions in the fetal-maternal interface. Thus, alterations in PROK1 expression and/or function lead to placenta-derived pregnancy complications. Recently published studies also indicate that PROK1 is associated with ovarian function and oocyte competence. However, limited data associating PROK1 with POR are published. This study uniquely investigates possible associations between PROK1 FF levels in POR cases, with stimulation outcome, as well as with FF levels of other factors related to ovarian functionality, namely VEGF, bone morphogenetic protein 15 (BMP-15) and Pigment Epithelium Derived Factor (PEDF).

Study design, size, duration
This prospective-observational study was collaboratively conducted between November 2020 and July 2021 at Genesis Athens Clinic and at the University of Athens Medical School. A total of 64 patients undergoing IVF treatment were enrolled. The study group comprised of 32 POR patients defined according to the Bologna criteria. The control group consisted of 32 normal responder women undergoing IVF due to tubal factor and/or mild male factor infertility. Patients with other infertility aetiologies were excluded.

Participants/materials, setting, methods
Participants in both groups received the standard short GnRH-antagonist protocol. Prior to ovarian stimulation, participants were subjected to basic infertility investigation, including antral follicle count and AMH levels evaluation. The FF samples were collected as part of the oocyte retrieval process, then centrifuged and stored at -80 °C till analysis. Follicular fluid levels of PROK1, VEGF, BMP-15 and PEDF were evaluated via ELISA employing commercially available kits. Statistical analysis was performed employing R Programming Language.

Main results and the role of chance
Significantly higher PROK1 (3229.63 ± 2372.66 vs 1945.95 ± 1408.01 pg/ml; P-value&lt;0.0001), VEGF (2309.63 ± 412.49 vs 2013.22 ± 330.16 pg/ml; P-value=0.006) and lower BMP-15 (434.13 ± 106.38 vs 532.5 ± 108.26 pg/ml; P-value=0.001) levels were recorded in the POR group. No difference was observed regarding PEDF levels (7.43 ± 1.95 vs 8.23 ± 2.54 ng/ml; P-value=0.2). However, the POR group presented with lower PEDF/VEGF ratio (3.33 ± 1.08 vs 4.18 ± 1.41; P-value=0.02), indicating a reduced antioxidant capacity. PROK1 levels were negatively correlated with AMH (P-value=0.04), number of oocytes retrieved (P-value=0.001) and number of MII oocytes (P-value=0.005). BMP-15 was positively correlated with number of oocytes retrieved (P-value&lt;0.001), number of MII oocytes (P-value=0.002), number of normally fertilized zygotes (P-value=0.007), number of cleavage stage embryos (P-value=0.03) and number of blastocysts (P-value=0.04). VEGF was negatively correlated with AMH (P-value=0.004) and number of oocytes retrieved (P-value=0.03). These correlations remained significant when adjusting for ovarian response status. PROK1 levels, with a cut-off value of 2854.25 pg/ml, were able to predict ovarian response status with an area under the curve at 0.64. Sensitivity was 0.55, specificity was 0.88, and accuracy was 0.71. The positive and negative predictive values were 81.82% and 66.67%, respectively.

Limitations, reasons for caution
Limitations of our study refer to the limited size of the studied population, as well as to the lack of data considering pregnancy outcomes. Moreover, molecular data with regards to the possible role of PROK1 on POR pathogenesis are required. Future studies are needed to verify the results presented herein.

Wider implications of the findings
Data presented herein indicate that PROK1 FF levels are strongly associated with diminished ovarian reserve and POR. Considering that FF-PROK1 presents with a similar profile with FF-VEGF, we can form the hypothesis that the compromised angiogenesis observed in POR patients leads to PROK1 and VEGF increase via a negative-feedback-loop.

Trial registration number
Not applicable