Researchers at Sweden’s Karolinska Institute have found that MEHP, a compound the body produces from the widely used plasticiser DEHP, damages not only follicle cells in human ovaries but also other surrounding tissue cells.
The study, led by scientists at the Karolinska Institute in Sweden, was published in the journal eBioMedicine. It shows that MEHP (mono-2-ethylhexyl phthalate), a compound formed in the body from DEHP (di-2-ethylhexyl phthalate), affects a broad range of cell types in ovarian tissue, not just the cells directly involved in reproduction. DEHP is used to make plastic more flexible in dozens of everyday products, including PVC pipes, cling wrap, shower curtains, medical tubing and eyelash glue, and it readily enters the bloodstream through food and the gut.
Previous research had focused mainly on follicle cells, which play a direct role in reproduction. The new findings reveal that MEHP also reaches other cell groups that support the ovary.
Pauliina Damdimopoulou, a reproductive biology specialist and senior author of the study, said the results show that phthalate compounds affect a much wider range of ovarian cells than the egg cells and follicles that have previously been the focus of research. She added that the most surprising finding was how highly sensitive the ovary’s nerve-related cells proved to be to this exposure.
The research was based on laboratory cultures of ovarian tissue samples collected from seven donors. Five samples came from ovaries removed during gender-affirming surgery, while the remaining two were obtained through biopsy during elective caesarean sections. None of the participants had a history of ovarian disease, and none were current smokers.
Each tissue sample was exposed to three different conditions over six days: a control group received no MEHP, while two other groups were exposed to MEHP at a concentration of 20.51 nanomoles per litre (nM) or at 1,000 times that level. The researchers noted that the 20.51 nM dose corresponds to a level people could realistically encounter, which they described as “epidemiologically relevant”.
Nervous system cells showed weaker resistance
Single-cell genetic analysis of a sample from a 23-year-old donor showed that exposure to MEHP altered gene activity, compared with the control group, across all seven cell types examined. In most cell types, the number of differentially expressed genes rose along with the dose, with changes affecting cell structure, adhesion and oxidative phosphorylation, the process that generates energy within cells.
By contrast, in glial cells, a recently identified nervous-system-related cell type found in the ovaries, raising the dose did not significantly change the number of differentially expressed genes. The authors interpret this as a sign of glial cells’ particular vulnerability to MEHP. The study also found that MEHP exposure disrupted communication between cells, with the effect more pronounced at higher doses.
In their conclusions, the researchers said the evidence confirms that phthalate compounds, even at concentrations found in real life, can disrupt the function of the human ovary beyond the boundaries of the follicle. They said the sensitivity of glial cells to MEHP could help explain the link between phthalate exposure and polycystic ovary syndrome, and argued that future toxicology research should not limit its focus to follicles alone.
Source: ScienceAlert
