Study
Shows Cause Of Infertility In Some Women With Endometriosis
Key Molecule Lacking In
Uterine Wall
Some women who have infertility
as a result of endometriosis lack molecules in the uterus that allow
the embryo to attach to the uterine wall, according to a report in the
medical journal Endocrinology.
The researchers suspect that because the
embryo cannot attach to the uterine wall, a pregnancy cannot become
established, and infertility results.
Endometriosis is a major cause of infertility, occurring
in from 35 percent to 50 percent of women who have difficulty becoming
pregnant.
The researchers also reported that a number of genes
present in the uteri of women with endometriosis appear to be functioning
inappropriately. Many of the genes identified in this study had not
been shown previously to contribute to endometriosis and the infertility
that commonly accompanies the disorder.
"The causes of endometriosis and of
the infertility that's associated with it have eluded scientists for
many years," says Dr. Duane Alexander, director of the National
Institute of Child Health and Human Development (NICHD), at
the National Institutes of Health (NIH).
"This study provides a better understanding of
this disease, and may lead to new therapies to treat women who have
the disorder," Dr. Alexander says.
The NICHD and the Office
of Research on Women's Health provided part of the funding
for the study.
The research builds upon an earlier NICHD-funded study,
which reported that the molecule L-selectin needs to be present on the
uterine wall before an embryo can attach itself to the uterus and a
pregnancy can begin.
In the current study, researchers found that at the
time the uterus is most receptive to the embryo, women with infertility
because of endometriosis have very low levels of an enzyme that is involved
in synthesizing the ligand for L-selectin.
The ligand is a rubber-band like molecule that tethers
L-selectin to the wall of the uterus. Because the women lack the enzyme
that makes the L-selectin ligand, the embryo may not be able to attach
to the uterine wall, and a pregnancy could not begin.
Endometriosis is a disorder in which endometrial tissue
-tissue that normally lines the inside of the uterus - begins growing
in other areas within a woman's abdomen, including on the fallopian
tubes, on the outside of the uterus, the ovaries, or intestines.
This disorder affects 10 percent to 15 percent of women
of reproductive age and often causes pelvic pain.
Scientists
Study Genes' Role
In this multicenter study, researchers
collected samples of endometrium from 15 non-pregnant volunteers, eight
with endometriosis and seven without. They did this during the "window
of implantation," the days of a woman's menstrual cycle (day 20-24
of a 28-day cycle) when the uterus is receptive to an embryo.
The scientists in this study used a new technology called
microarray analysis, which makes it possible to screen a large number
of genes at one time. This allows researchers to identify genes much
more quickly than do traditional methods that look for only one gene
at a time.
The researchers measured gene expression - the turning
on or off of a particular gene.
They analyzed over 12,000 genes. They found 91 genes
that had more than a two-fold increase in gene expression in women with
endometriosis, compared to those without the disease, and 115 genes
that had more than a two-fold decrease in expression in women with endometriosis
compared to those without.
These genes are likely to play a role in the development
of endometriosis in the pelvis and its associated infertility.
"This study's findings support the theory that
women who have this abnormal tissue are prone to develop endometriosis
and its infertility," says the study's senior author, Dr. Linda
Giudice, director of the Center for Research on Women's Health and Reproductive
Medicine at Stanford University.
Hope
for New Treatments
Dr. Giudice explains that the study's
findings might lead to a new way to screen women for the disease. Currently,
diagnosis requires a laparoscopy (a procedure in which a small incision
is made in the abdomen) or laparotomy (a larger incision is made), usually
with a general anesthetic.
This new research may one day enable scientists to develop
a less invasive test, based on the detection of abnormal gene activity,
she says.
Dr. Giudice says that the study's findings need to be
verified in larger studies of women who have endometriosis.
Nonetheless, she says, "This now offers
an opportunity to create drugs to correct this error in gene expression,
and therefore a treatment for endometriosis-related infertility."
Always consult your physician for a diagnosis.
What
Is Endometriosis?
The name comes from the word "endometrium",
which is the tissue that lines the uterus.
During a woman's regular menstrual cycle, this tissue
builds up and is shed if she does not become pregnant. Women with endometriosis
develop tissue that looks and acts like endometrial tissue outside the
uterus, usually on other reproductive organs inside the pelvis or in
the abdominal cavity.
Each month, this misplaced tissue responds to the hormonal
changes of the menstrual cycle by building up and breaking down just
as the endometrium does, resulting in internal bleeding.
Unlike menstrual fluid from the uterus which is shed
by the body, blood from the misplaced tissue has nowhere to go, resulting
in the tissues surrounding the endometriosis becoming inflamed or swollen.
This process can produce scar tissue around the area
which may develop into lesions or growths. In some cases, particularly
when an ovary is involved, the blood can become embedded in the tissue
where it is located, forming blood blisters that may become surrounded
by a fibrous cyst.
Always consult your physician for more information.
Online
Resources
American
College of Sports Medicine
American
Society for Reproductive Medicine (ASRM)
Centers
for Disease Control and Prevention (CDC)
HealthierUS.Gov
National
Institutes of Health (NIH)
National
Women's Health Information Center
Office
of Research on Women's Health |
August 2003
In
This Issue:
Study
Shows Cause Of Infertility In Some Women With Endometriosis
Scientists
Study Genes' Role
Hope
for New Treatments
What
Is Endometriosis?
Calcium
Can Be Critical Before Menopause
Nutritional
Needs After Menopause
Online
Resources
Other
Resources:
Find
a St. John's Mercy Physician
Women's
Services at St. John's Mercy
Women's
Health Information
St.
John's Mercy Classes and Programs
Calcium
Can Be Critical Before Menopause
Many women start taking
calcium supplements during menopause, but calcium deficiency increasingly
is being seen in younger women, according to a report in the Mayo
Clinic Women's HealthSource.
Women who are not getting
enough calcium in their diets should take a supplement, regardless
of their age, experts say.
Women should ask their physician
how much calcium is needed because the amount required changes based
on age and health factors.
A physician also can recommend
which kind of calcium supplement should be taken, when to take it
for best absorption, and if it should be combined with vitamin D or
other minerals.
If dietary intake of calcium
is insufficient, calcium supplements can provide special benefit to
the bones at certain times in life, such as puberty or in early menopause.
But at any age, calcium
benefits a woman's bones as well as muscles and nerves.
A well-balanced diet can
provide all the calcium a woman needs. Good sources of calcium include:
dairy products; vegetables such as broccoli, spinach, brussels sprouts
and kale; tofu; calcium-fortified juices, cereals and breads; and
canned fish, such as salmon.
Always consult your physician
for a diagnosis.
Nutritional
Needs After Menopause
As a person ages, nutritional
requirements change.
A premenopausal woman should
consume about 1,000 mg of calcium daily. Women after menopause should
consume 1,200 mg of calcium per day, according the American
Academy of Orthopaedic Surgeons.
Vitamin D is also very important
for calcium absorption and bone formation.
According to a 1992 study,
women with postmenopausal osteoporosis who took vitamin D for three
years, significantly reduced their risk of spinal fractures.
This issue is controversial,
however, as vitamin D can cause kidney stones, constipation, or abdominal
pain, especially in women with kidney problems.
Other nutritional guidelines
recommended by the National Research Council of the National
Institutes of Health include:
Choose foods low in fat,
saturated fat, and cholesterol. Fat intake should be less than 30
percent of daily calorie intake.
Eat fruits, vegetables,
and whole grain cereal products, especially those high in vitamin
C and beta carotene. Persons of all ages should consume 20 to 30 grams
of fiber daily.
Avoid foods and drinks with
processed sugar, as many of these products contain empty calories
and promote weight gain.
Avoid salt-cured and smoked
foods such as sausages, smoked fish, ham, bacon, bologna, and hot
dogs. These foods are high in sodium, which can lead to high blood
pressure, a serious risk for aging women.
Always consult your physician
for more information.
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