Tumor necrosis factor alpha and milk fat globule-epidermal growth factor 8: Novel biomarkers to predict implantation failure and pregnancy loss

Objective To determinate whether implantation failure (IF) and recurrent pregnancy loss (RPL) can be predicted in serum prior to in vitro fertilization (IVF)?. Design Multicentric prospective controlled pilot clinical study from January 2016 to January 2020. Material and methods Thirty women ages 21-35 years were recruited from 3 groups: fertile controls (C), unexplained IF (following 3 failed good quality embryo transfers), and RPL (at least 2 unexplained first trimester miscarriages) in their natural cycle in which serum tumor necrosis factor (TNFα) and milk fat globule-epidermal growth factor 8 (MFG-E8) estradiol (E2) and progesterone (P4) levels were quantified in the early proliferative (cycle day 2) and secretory phases (urinary luteinizing hormone (LH)+7 days). Additionally, an endometrial biopsy was obtained on urinary LH+7 days for MFG-E8 and TNF α protein and gene expression analysis. Results Ten women were assigned to each group. No statistical differences were found in age, body mass index, antimullerian hormone, baseline follicle stimulating hormone and baseline antral follicle count among cohorts. Mean serum E2 and P4 levels were similar among all groups in both the proliferative and secretory phases: E2 proliferative (C 69.19±26.64 pg/ml, IF 64.19±32.56 pg/ml, RPL proliferative 57.44±38.51; p= 0.55), E2 secretory (C 164.10±52.57 pg/ml, IF 172.57±121, RPL 173.81±.97.35; p=0.25), P4 proliferative (C 0.45±0.15 ng/ml, IF 0.45±0.19 ng/ml, RPL 0.53±0.18 ng/ml; p=0.85), P4 secretory (C 7.42±4.06 ng/ml, IF 7.8±4.56 ng/ml, RPL 8.05±4.38 ng/ml; p= 0.74). Mean serum TNFα levels were significantly higher in both, the proliferative and secretory phases for the RPL group (proliferative RPL 9.98±4.47 pg/ml, IF 4.73±2.56 pg/ml, C 3.42±1.01 pg/ml; p=0.001 vs secretory RPL 8.67±4.45 pg/ml, C 3.35±0.94 pg/ml, IF 3.85±1.01 pg/ml; p= 0.03). Mean serum MFG-E8 levels were significantly higher in the IF group during the proliferative phase (IF 373±201 pg/ml, RPL 201±115 pg/ml, C 225.58±109.73pg/ml; p=0.03), but not in the secretory phase (IF 237±101 pg/ml, RPL 189±116 pg/ml, C 199.41±112.43 pg/ml; p=0.15). Endometrial MFG-E8 mRNA levels were significantly lower in the IF and RPL group compared to C (p=0.03). TNFα mRNA levels were not statistically significant among groups (p=0.12). Conclusions TNFα and MFG-E8 serum levels may serve as serum markers to predict IF and RPL.