Register for Transient uterine ischemia hypothesized to kill fibroids
Uterine LeiomyomasAugust 19, 2004
2004 AUG 19 - (NewsRx.com & NewsRx.net) -- Researchers hypothesize that transient uterine ischemia, the process that kills trophoblasts, also kills leiomyomas, or uterine fibroids.
"When the uterine arteries are bilaterally occluded, either by uterine artery embolization or by laparoscopic obstruction, women with myomas experience symptomatic relief. After the uterine arteries are occluded, most blood stops flowing in myometrial arteries and veins, and the uterus becomes ischemic. It is postulated that myomas are killed by the same process that kills trophoblasts: transient uterine ischemia," wrote F. Burbank and colleagues in the Journal of the American Association of Gynecologic Laparoscopists.
"When the uterine arteries are bilaterally occluded, either by uterine artery embolization (UAE) or by laparoscopic obstruction, women with myomas experience symptomatic relief. After the uterine arteries are occluded, most blood stops flowing in myometrial arteries and veins, and the uterus becomes ischemic.
"Over time, stagnant blood in these arteries and veins clots. Then, tiny collateral arteries in the broad ligament (including communicating arteries from the ovarian arteries) open, causing clot within myometrium to lyse and the uterus to reperfuse," Burbank and coauthors explained.
They pointed out that "[m]yomas, however, do not survive this period of ischemia. This is unique organ response to clot formation and ischemia."
"What allows the uterus to survive a relatively long period of ischemia while myomas perish?" the researchers asked.
"Childbirth appears to be the predicate biology," they said.
"Following placental separation, the uteroplacental arteries and the draining veins of the placenta are torn apart at their bases in the junctional zone of the myometrium and bleed directly into the uterine cavity. Left unchecked, every woman would bleed to death in less than 10 minutes after placental delivery.
"Most women do not bleed to death because vessels in the uterus clot after placental delivery. During pregnancy, clotting and lytic factors in blood increase many-fold. Following delivery, uterine contractions continue, intermittently, periodically slowing the velocity of flowing blood through myometrium," the authors continued.
"The combination of slowed blood flow, elevated clotting proteins, and torn placental vessels (known as Virchow's triad) causes blood in myometrial arteries and veins to clot," they said. "Fibrinolytic enzymes later lyse clot in arteries and veins not associated with placenta perfusion, and the uterus is reperfused. Remnant placental tissue - primarily uteroplacental arteries and veins - does not survive this period of ischemia. Placental tissue dies and over weeks is sloughed into the uterine cavity. At the same time, residual endometrial tissue grows under the sloughing placental tissue thus re-establishing the endometrial lining."
Thus, Burbank and colleagues concluded, "It is postulated that myomas are killed by the same process that kills trophoblasts: transient uterine ischemia."
Burbank and coauthors published their study in the Journal of the American Association of Gynecologic Laparoscopists (Childbirth and myoma treatment by uterine artery occlusion: Do they share a common biology? J Am Assoc Gynecol Laparosc, 2004;11(2):138-152).
Additional information can be obtained by contacting F. Burbank, 12 Old Ranch Rd., Laguna Niguel, CA 92677 USA.
The publisher of the Journal of the American Association of Gynecologic Laparoscopists can be contacted at: Journal American Association Gynecologic Laparoscopists, 13021 East Florence Ave., Santa Fe Springs, CA 90670-4505 USA.
The information in this article comes under the major subject areas of Gynecology, Leiomyomas, and Women's Health. This article was prepared by Women's Health Weekly editors from staff and other reports. Copyright 2004, Women's Health Weekly via NewsRx.com & NewsRx.net.
©Copyright 2004, Women's Health Weekly via NewsRx.com & NewsRx.net
