Antioxidants – vitamins that hunt oxygen-free radicals that trigger ageing and
disease – are sold over the counter everywhere and added to food, beverages and
face cream. But according to Weizmann Institute of Science Prof. Nava Dekel of
the biological regulation department, scientists still lack a complete
understanding of how they act.
New research on rodents by Dekel and her
team, recently published in the Proceedings of the [US] National Academy of
Sciences, has revealed a possible unexpected side effect of antioxidants – they
might cause fertility problems in females.
Common antioxidants include
vitamins C and E. These work by eliminating free radical molecules produced
naturally in the body. Stress can cause these chemically active molecules to be
overproduced; in large amounts, they damage cells indiscriminately. By
neutralizing these potentially harmful substances, antioxidants can
theoretically improve health and slow the aging process.
But when Dekel
and her research team – including her former and present doctoral students Dr.
Ketty Shkolnik and Ari Tadmor – applied antioxidants to the ovaries of female
mice, the results were surprising– ovulation levels dropped significantly. That
is, very few eggs were released to reach the site of fertilization, compared to
untreated ovaries.
To understand what lies behind these initial findings,
the team asked whether ovulation might rely on the very “harmful” oxygen
radicals destroyed by antioxidants.
Further testing in mice showed that
this is, indeed, the case. In one experiment, for instance, Dekel and her team
treated some ovarian follicles with luteinizing hormone, the physiological
trigger for ovulation, and others with hydrogen peroxide, a reactive oxygen
species. The results showed hydrogen peroxide fully mimicked the effect of the
ovulation-inducing hormone. This implies that reactive oxygen species produced
in response to luteinizing hormone serve, in turn, as mediators for this
physiological stimulus leading to ovulation.
Among other things, these
results help fill in a picture that has begun to emerge of fertility and
conception, in which it appears that these processes share a number of common
mechanisms with inflammation. It makes sense, says Dekel, that substances that
prevent inflammation in other parts of the body might also interfere with normal
ovulation, thus more caution should be taken when administering such
substances.
Much of Dekel’s research has focused on fertility; her
previous results are already helping some women become
pregnant.
Ironically, the new study has implications for those seeking
the opposite effect. Dekel explains that “on the one hand, these findings could
prove useful to women who are having trouble getting pregnant. On the other,
further studies might show that certain antioxidants might be an effective means
of birth control that could be safer than today’s hormone-based
prevention.”
Dekel and her team are now planning further studies to
investigate the exact mechanics of this step in ovulation, and to examine its
effect on mice when administered in food or drink. They also plan to collect
data on the possible link between females being administered antioxidant
supplements and having difficulty in conceiving.
STEM CELL MODEL FOR
PERSONALIZED MEDICINE A unique model for research into and treatment of heart
diseases leading to fatal irregular heartbeat has been developed using iPSCs
(induced pluripotent stem cells) by researchers at Haifa’s Rambam Medical Center
and the Technion-Israel Institute of Technology. The discovery was recently
reported in Nature. Ilanit Itzhaki, Leonid Maizels, Irit Huber and colleagues in
Prof. Lior Gepstein’s lab turned skin cells taken from a female patient
suffering from the inherited disease called congenital long QT syndrome” into
unique stem cells and then used them to create a “cardiac cell laboratory.” The
ability to generate patient-specific human-induced pluripotent stem cells, they
wrote, offers a new paradigm for modelling human disease and individualizing the
testing of potential drugs. The heart cells they created expressed the
characteristic electrical disruption in the syndrome she suffered from and
effects of medications that could alleviate the condition.
The research
“represents a promising paradigm to study disease mechanisms, optimize patient
care (personalized medicine) and aid in the development of new therapies,” they
wrote.
HOPE FOR BALD HEADS American researchers claim to have discovered
the cause of male-pattern baldness and suggest that stem cells can create new
hair.
University of Pennsylvania scientists say a defect in the cells
causes the hair that is produced to be so thin it appears invisible to the naked
eye, creating a bald spot or receding hairline, the BBC and UPI reported. They
maintain that restoring the normal function of the cells could eliminate the
bald appearance.
The study found that although bald areas had the same
number of hairmaking stem cells as normal scalp, there were fewer of a more
mature type, known as progenitor cells. As a result, hair follicles in bald
areas shrink, and the new hairs produced are microscopic compared to normal
hair.
“This implies that there is a problem in the activation of stem
cells converting progenitor cells in bald scalp,” said research leader George
Cotsarelis. “The fact that there are normal numbers of stem cells in bald scalp
gives us hope for reactivating those stem cells,” he said.