Telomerase implicated in endometriosis

Telomerase, the enzyme that adds DNA sequence repeats to chromosomal telomeres, extending their length, has been implicated in the common female complaint, endometriosis.

Endometriosis, thought to affect one in five women, involves endometrial tissue growing outside the uterus, usually in the abdominal cavity or pelvis, causing severe pain and in many cases infertility.

A new study by researchers from the University of Liverpool has found that telomerase, which is found in endometrial cells, in sperm and egg cells and in cancer cells, is overexpressed during the menstrual cycle of women with the condition.

They also found that telomeres, which cap the ends of chromosomes and protect them from damage, are abnormally long in women with endometriosis.

"During menstruation telomeres normally shorten in length with each cycle of cell division until they reach a certain length at which they can no longer divide," lead author Dr Dharani Hapangama said.

"(Telomerase) can extend the length of the telomeres so that they can continue to divide and this can happen in some special cells such as sperm and egg cells, but not normally in cells that make up the organs of the body.

"Our research shows, however, that cells in the lining of the womb are unique in that they can express this enzyme in the early stages of the menstrual cycle when cell division is important, but not during the latter stages when implantation of the fertilised embryo becomes a priority.

"Women who have endometriosis express this enzyme in both the early and late stages of the menstrual cycle which means that the cells will continue to divide and lose their 'focus' in supporting the establishment of a pregnancy.

"As a result the lining of the womb may be more hostile to an early pregnancy, and the cells that are shed at this late stage in the menstrual cycle may be more 'aggressive' and more able to survive and implant outside the uterus, causing pain in the pelvic or abdomen area."

The research is published in Human Reproduction