When the function of the endothelial cells is disrupted, women can have miscarriages, suffer from pre-eclampsia or become infertile.
There are thousands of chemicals (industry chemicals, products of combustion, hygiene products and pesticides) which look like and imitate hormones. Chemicals that can disturb the natural rhythm and regulation through hormones in the body are called endocrine disrupting chemicals. The amount of endocrine disrupting chemicals that we are exposed to increases significantly every year; more or less all humans and animals on the planet have measurable levels in their blood.
In the autumn 2012, the WHO published a large research report showing that a number of diseases can be connected to the exposure to endocrine disrupting chemicals: breast and prostate cancer, endometriosis, infertility, diabetes and cardiovascular diseases, early onset of puberty and obesity. Exactly how the chemicals cause these diseases is generally not known.
Doctoral student Malin Helmestam at the Department of Women’s and Children’s Health has, together with colleagues, studied how a few different endocrine disrupting chemicals affect endothelial cells from the endometrium, the inner mucous membrane in the uterus. Endothelial cells are important to the regeneration of blood vessels. The main function of the endometrium is to receive and implant a fertilised embryo and it is dependent on blood vessels with normal function. Disruptions in the function of the endothelial cells can lead to disruptions of the regeneration of blood vessels and thereby cause increased risk of miscarriage, pre-eclampsia, infertility, irregular periods and endometriosis. The endothelial cells in the endometriosis are partly regulated by oscillations in levels of the sex hormones oestrogen and progesterone.
The study investigates the effects of cadmium (a heavy metal with oestrogen-like properties), tamoxifen (a breast cancer drug which inhibits oestrogen), mifepristone (a drug used for medical abortion which inhibits progesterone) and bisphenol A (an industrial chemical with oestrogen-like properties).
“It turned out that all four chemicals affect endothelial cells from human endometrium”, says Malin Helmestam.
The thesis shows that chemicals with endocrine disrupting properties have the ability to affect the expression of certain growth factors that are important to the regulation of growth of new blood vessels in the endometrium. Other studies have shown that disruptions of this particular group of growth factors can cause irregular periods, endometriosis, reduced fertility and pre-eclampsia.
“This means that exposure to hormone disrupting chemicals can lead to diseases with a large effect on the woman’s quality of life. A reduced amount of hormone disrupting chemicals in our environment would probably contribute to these diseases becoming less frequent”, says Malin Helmestam.