Onderzoek helpt de rol van oestrogeen in het geheugen
te deconstrueren
UWM onderzoeker onthult nieuwe details over de
mechanismen van de receptor.
Het verlies van oestrogenen tijdens de menopauze verhoogt
bij de vrouw het risico op dementie en de ziekte van
Alzheimer, maar hormoon vervangende therapie kan schadelijke
bijwerkingen veroorzaken.
Het kennen van het exacte mechanisme van oestrogeen
activatie in de hersenen kan helpen om geneesmiddelen te
ontwikkelen die ervoor kunnen zorgen dat vrouwen van
middelbare leeftijd de voordelen hebben van
hormoonvervangende therapie zonder de risicoverhoging op het
krijgen van hart- en vaatziekten of borstkanker.
In een nieuwe studie onthult Karyn Frick, hoogleraar
psychologie aan de University of Wisconsin-Milwaukee (UWM),
details over de rol van oestrogeen in de complexe cellulaire
communicatiesysteem onderliggende geheugenvorming.
Dr. James G. Schwade reports on a possible
new link between estrogen use and the activation or aggravation of certain types of
aggressive cancer.
Revealing estrogen's secret role in obesity
Research on the effects of the female sex hormone estrogen in the brain lend credence to
what many women have suspected about the hormonal changes that accompany aging: Menopause
can make you fat. In animal experiments, researchers showed how estrogen receptors in the
brain serve as a master switch to control food intake, energy expenditure and body fat
distribution. The study will be presented in August at the American Chemical Society
national meeting in Boston.
the female sex hormone estrogen turns on a gene linked to breast cancer, according to new
research by Brisbane scientists. The cancer biology team from UQ's Diamantina Institute
for Cancer, Immunology and Metabolic Medicine, believe their finding will help explain the
link between breast cancer and high levels of estrogen. What we've shown is that the
ability of estrogen to switch this gene on is important for the growth of breast cancer
cells, Diamantina cancer biology research leader Professor Tom Gonda said. The gene
they studied, known as MYB, is found in about 70 percent of all breast cancers and is one
of several dozen genes called oncogenes that promote cancer growth. What's important
in breast cancer is the ability of estrogen to turn on MYB rather than there being a
mutation in the gene itself, Professor Gonda said.
Improved estrogen reception may
sharpen fuzzy memory
Finding ways to boost the brain's estrogen receptors may be an alternative to adding
estrogen to the body in efforts to improve cognition in postmenopausal women and younger
women with low estrogen levels, according to neuroscientists at the University of
Florida's McKnight Brain Institute.
Estrogen therapy could be dangerous
for women with existing heart risk
Hormone therapy could accentuate certain pre-existing heart disease risk factors and a
heart health evaluation should become the norm when considering estrogen replacement, new
research suggests. The research also showed that in women without existing
atherosclerosis, hormone therapy use included some positive effects on lipids but also
some negative effects related to heart health, said MaryFran Sowers, lead researcher and
professor of epidemiology at the University of Michigan School of Public Health. The U-M
study came about, Sowers said, in trying to explain what's behind the so-called timing
hypothesis. The timing hypothesis suggests that if a woman implements a hormone therapy
program within six years of her final menstrual period, this narrow window is enough to
deter heart disease from developing with the onset of menopause. But the U-M findings
suggest that explanation isn't quite so simple, Sowers said. Even within the six-year
window, there were negative aspects related to heart disease. While the positive outcomes
on HDL and LDL cholesterol levels were observed, Sowers said, researchers also saw
negative outcomes in terms of the inflammation processwhich can be related to heart
disease.
Estrogen is important for bone health in
men as well as women
Although women are four times more likely than men to develop osteoporosis, or porous
bone, one in 12 men also suffer from the disease, which can lead to debilitating
fractures. In women, low estrogen levels after menopause have been considered an important
risk factor for this disorder. Now research at Washington University School of Medicine in
St. Louis has shown that low amounts of active estrogen metabolites also can increase the
risk of osteoporosis in men.
Studies of low-dose effects of xenoestrogens have yielded conflicting results that may be
attributed to differences in estrogen sensitivity between rodent strains. Perinatal
exposure of CD-1 mice to low doses of the xenoestrogen bisphenol A (BPA) alters
peripubertal mammary gland development. Future studies of BPA action require estrogen
receptor knock-out mice that were generated on a C57Bl6 background. Wadia et al. (p. 592)
examined whether the mammary glands of CD-1 and C57Bl6 mice exhibited similar responses to
17?-estradiol (E2) and whether perinatal exposure to BPA equally enhanced sensitivity of
the mammary glands to E2 at puberty.
Among the more insidious aspects of cancer is its capacity for escaping the anticancer
defenses of the host. New research suggests that some estrogens may further reinforce this
evasion of host immunity, even as those same hormones stimulate the growth and spread of
hormone-responsive cancers. According to David Shapiro, a medical and biochemistry
professor at the University of Illinois at UrbanaChampaign, the new findings
highlight the role that estrogen-related interference with immune cell function may play
in the development and progression of breast cancer.
Study Describes Action of Estrogen in
Protecting Bone
Researchers at the University at Buffalo have described a novel pathway by which
estradiol, the primary estrogen in humans, aids in maintaining bone density, a function
critical to avoiding osteoporosis.It is well known that estrogen is essential for healthy
bone, and that when the production of estrogen is reduced, as occurs normally in
postmenopausal women and pathogenically after exposure to radiation or chemotherapeutic
drugs, bones become brittle and break easily. However, the mechanisms involved aren't
clearly understood. The new study found that one way estradiol helps to maintain bone
density is by stopping the activation of an enzyme known as caspase-3. Also called the
executioner caspase, caspase-3 is the central player in initiating the process of
apoptosis, or programmed cell death of osteoblasts, the bone cells that aid in the growth
and development of new bone and teeth.
Estrogen Use Before 65 Linked to Reduced
Risk of Alzheimers Disease
Women who use hormone therapy before the age of 65 could cut their risk of developing
Alzheimers disease or dementia. This possibility is raised by research that will be
presented at the American Academy of Neurologys 59th Annual Meeting in Boston. The
study found women who used any form of estrogen hormone therapy before the age of 65 were
nearly 50 percent less likely to develop Alzheimers disease or dementia than women
who did not use hormone therapy before age 65.