VASCULAR SMOOTH-MUSCLE ALPHA-ACTIN DISTRIBUTION AROUND ENDOMETRIAL ARTERIOLES DURING THE MENSTRUAL-CYCLE - INCREASED EXPRESSION DURING THE PERIMENOPAUSE AND LACK OF CORRELATION WITH MENORRHAGIA

Menorrhagia affects similar to 9% of all women, increasing to 20% duri ng the perimenopause. The majority of menstrual loss occurs through th e spiral arterioles - specialized endometrial vessels that are intimat ely involved in controlling menstruation, Our aim was to compare the d istribution of vascular smooth muscle alpha-actin using immunohistoche mical techniques in the endometrium of women before and during the per imenopause and with or without menorrhagia, We hypothesized that diffe rences in vessel numbers and types exhibiting alpha-actin staining wou ld exist between these groups, reflecting structural/functional differ ences. The results showed that perimenopausal menorrhagic women had si gnificantly more smooth muscle alpha-actin expression than non-perimen opausal controls in four out of five menstrual cycle stages (P < 0.05) , while perimenopausal non-menorrhagic women demonstrated a significan t increase at the mid-proliferative stage only (P < 0.007), No signifi cant differences occurred between women with or without menorrhagia be fore or during the perimenopause. Perimenopausal women had significant ly more straight arterioles (P < 0.02) than women prior to perimenopau se at the late secretory stage, while non-perimenopausal women demonst rated significantly higher numbers of spiral arterioles (P < 0.002) in the early secretory stage, although this difference had disappeared b y the late secretory stage, In conclusion, we found no major differenc es in endometrial vascular smooth muscle alpha-actin staining between women with and without menorrhagia, but significant increases in alpha -actin staining in women showing perimenopausal symptoms.