Objective: Endocrine Society classified patients with serum 25-hydroxyvitamin D [25(OH)D] levels below 20 ng/ml as deficiency, 20-30 ng/ml as insufficiency, and >30 ng/ml as replete. This study was planned to investigate the relationship between serum vitamin D level and homeobox 10 mRNA expression in women with polycystic ovary syndrome (PCOS).
Patients and methods: Thirty women with PCOS who failed the first IVF/ICSI attempt and were decided to have endometrial injury before second attempt were included in the study. Before the endometrial injury, the serum vitamin D levels of the women were measured, and they were divided into three equal groups as proposed by the Endocrine Society. Group 1 consisted of vitamin D deficient women (<20 ng/mL), Group 2 consisted of vitamin D insufficient women (20-30 ng/mL), and Group 3 consisted of vitamin D replete women (>30 ng/mL). Women in each group were injured with a Pipelle cannula during mid-luteal phase. Endometrial samples collected during injury were analyzed for HOXA10 mRNA expression by RT-PCR and correlated with serum vitamin D level.
Results: When analyzing the results according to different vitamin D thresholds, as proposed by the Endocrine Society, HOXA10 mRNA expression was comparable between vitamin D deficient and vitamin D insufficient women. The HOXA10 mRNA expression of vitamin D replete women(Group 3) was found to be higher than both vitamin D deficient (Group 1) and vitamin D insufficient women (Group 2). HOXA10 mRNA expression of the women in Group 3 was 3.3-fold higher than Group 1 and 2.6-fold higher than Group 2. HOXA10 mRNA expression was correlated to the levels of vitamin D in the Group 3 (r=0.655, p=0.02). There was no significant correlation between serum vitamin D levels and endometrial HOXA10 mRNA expression of women in both Group 1 (r=0.343, p=0.06) and Group 2 (r=0.456, p=0.08).
Conclusions: Endometrium of women with PCOS with sufficient serum vitamin D levels express significantly higher HOXA10 mRNA than patients with low serum vitamin D levels.