For many women the pressure of childbirth leaves the uterus unable to bounce back to it’s pre-labor condition, but new research out of Boston has identified a protein responsible for elasticity, and it may one day serve as a treatment for recovery after childbirth. Pelvic organ prolapse is a condition where the pelvic diaphragm becomes lax, losing its dome shape and becoming more like a funnel, which bulges down into the vaginal canal. Normally the diaphragm is shaped like a trampoline and has the function of resisting pressures from inside the abdomen.
Prolapse is caused by direct or indirect damage to the pelvis or its supporting structures. Pregnancy, labor and childbirth can all cause stretching, detachment, and tearing of the vaginal muscles, resulting in the dropping of the pelvic diaphragm.
Treatment options include hormone replacement therapy and surgery. But now researchers at Massachusetts Eye and Ear Infirmary have identified a protein in body tissues that is crucial for elasticity, and might one day become a treatment option for pelvic organ prolapse.
The protein is called LOXL1 and it belongs to the protein family called lysyl oxidase. The researchers did their experiments on mice, which involved inactivating or "knocking out" various genes known to be involved in producing LOX proteins. As genes were eliminated, the scientists studied the mice to see what happened to the animals.
When LOXL1 was knocked out, the female mice underwent pelvic prolapse. Mice of both genders developed enlarged airspaces in the lungs, increased laxity of the skin, and the aorta — the main artery of the heart — did not expand and constrict the way it should.
The discovery of pelvic prolapse in the experimental mice was "unexpected" according to the researchers, since it is a condition that often occurs after giving birth. In humans, the womb expands to the size of a basketball to accommodate the growing fetus, but after giving birth it snaps back to the size of a pear. That is if LOXL1 is functioning properly.
In the study, depriving mice of LOXL1 induced prolapse without pregnancy, reinforcing the idea that the protein is necessary for making elastic fibers.
In a letter to the journal Nature Genetics, published in February, the researchers write, "LOXL1 seems to function primarily to guide elastin deposition in a spatially defined manner, a prerequisite for the formation of functional elastic fibers."
This means LOXL1 appears to play a crucial role in the maintenance of elastic fibers and in determining where they will be strung in the body. Elastic fibers can only function if they are cross-linked and form a scaffold. LOXL1 is the protein responsible for laying new fibers onto the scaffold.
In order for LOXL1 to be used as a treatment for pelvic prolapse, researchers must first develop a safe and effective means of delivering it to the affected tissues of the pelvis. The other option is to find a way of boosting the body’s natural production of LOXL1.
