Endometriosis is an oestrogen-dependent disease defined by the presence of epithelial, stromal and muscle cells outside the uterine cavity, which is associated with severe pain and infertility and affects about 15% of women of childbearing age [1]. There is evidence that the status of essential trace elements, such as zinc, plays a role in the progression of endometriosis. Endometriosis appears to be associated with impaired zinc homeostasis [2, 3] and altered mucin expression and glycosylation [4], processes that are related to altered zinc status [5]. However, the influence of zinc on endometriosis and the connection with an altered mucin O-glycome are unclear. Furthermore, there is little data on the general trace element status of endometriosis patients and the underlying mechanisms by which metals influence this disease have not yet been investigated.

The aim of this study is therefore to analyze the trace element status of patients and mucin O-glycome in endometriosis lesions.

Endometriosis patients with peritoneal, ovarian or deep infiltrating endometriosis were recruited for the study. The status of trace elements in serum and peritoneal fluid was analysed using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) and a fluorescence-based assay for the detection of free zinc [6]. The results show different levels of free zinc, manganese and selenium in the serum compared to non-diseased individuals and indicate a connection between an altered homeostasis of these trace elements and disease severity. To elucidate mucin expression and secretion during endometriosis, a screening of the mucin O-glycome was carried out using the ENDOMET Turku Endometriosis Database (https://endometdb.utu.fi/) and performing (immune)histochemical staining of selected mucins (MUC1, MUC5AC, MUC6, MUC16) as well as of neutral and acidic mucus. Here, several glycogenes were deregulated and MUC1, MUC5AC and MUC16 were significantly overexpressed in endometriosis lesions.

This study provides the first insight into the connection between endometriosis and an altered trace element status and the mucin O-glycome

References
[1] Velho, R.V., Int J Mol Sci, 2021. 22(23).
[2] Yılmaz, B.K., J Obstet Gynaecol, 2020. 40(4): p. 541-545
[3] Lai, G.L., Reprod Toxicol, 2017. 74: p. 77-84
[4] Konrad, L., Reproductive Sciences, 2019. 26(1): p.49-59
[5] Maares, M., Int J Mol Sci, 2020. 21(17): p. 6149
[6] Alker, W. Int J Mol Sci, 2019. 20(16).