Endometriosis - Causes

Candida. There is absolutely no evidence that endometriosis is caused by candida (commonly called yeast infection), as claimed in some consumer publications.

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Causes of Persistence and Growth of Endometriosis

There are two basic mysteries surrounding the persistence and growth of endometriosis:

Why do endometrial implants survive the attack by the immune system, which is typically launched against any foreign presence in the body?
How do these endometrial travelers develop new blood vessels and implant themselves in other locations?

Impaired Immune System.Some research is focused on possible immune disorders in women with endometriosis. One theory proposes that women with endometriosis have fewer natural killer (NK) cells, which are factors in the immune system important for surveillance. In their absence, the immune system is weakened and may allow endometrial tissue to invade and take root. A recent study suggests that other types of immune system cells are also underactive in women with endometriosis, allowing the woman's body to tolerate the implanted tissue.

Some evidence suggests that endometriosis represents an autoimmune condition, in which the immune system launches an attack on its own cells and tissue. Much of the evidence rests on the relatively high incidence of other inflammatory autoimmune disorders (e.g., multiple sclerosis, rheumatoid arthritis, lupus) that occur in women with endometriosis. It is unclear, however, how this response relates to endometriosis itself and whether endometriosis should be treated as an autoimmune condition.

Growth Factors and Angiogenesis. Macrophages also produce growth factors, which are of particular interest because they play important roles in angiogenesis, a natural process by which new blood vessels form.

Vascular endothelial growth factor (VEGF) is secreted by endometrial cells, and so is of special interest. Under normal conditions, VEGF is secreted within the uterus. When oxygen levels drop following menstruation and blood loss, VEGF levels rise and promote the growth of new blood vessels. This process is important for repairing the uterus following menstruation.

When endometrial cells land outside the uterus, however, investigators theorize that this same process occurs with unfortunate results. The cells secrete VEGF when they are deprived of blood and oxygen, which in turn stimulates blood vessel growth. In this case, however, blood vessel growth serves to promote implantation outside the womb.

Other growth factors involved in angiogenesis that may play a role in endometriosis include transforming growth factors (such as TGF-beta), platelet-derived endothelial growth factor (PD-ECGF), and tumor necrosis growth factors.