Gene transfer allows mammals to produce
Study with transgenic mice could
lead to omega-3-containing meats, dairy products
BOSTON - February 4, 2004 - Researchers from Massachusetts
General Hospital (MGH) have found that tissues from mice transgenic
for a gene usually found in the c.elegans roundworm contain
omega-3 fatty acids, consumption of which has been shown to protect
against heart disease. Usually mammals cannot produce omega-3s from
the more abundant omega-6 fatty acids, which do not have the health
benefits of omega-3s. The finding, published in the February 5 issue
of Nature, could lead to development of omega-3-rich meat,
milk and eggs.
Many studies have confirmed that consumption of omega-3s can reduce
the incidence and effects of cardiovascular disease for both the
general public and those with existing disease. The American
Heart Association currently recommends consumption of two or
more weekly servings of fish, particularly fatty fish like trout
and salmon, which are naturally high in omega 3s.
"Correction of the usually omega-3-deficient Western diet has
become a key step toward reducing the risk of several modern diseases,"
says lead author Jing X. Kang, MD, PhD, of the MGH Department of
Medicine. "The current approach to increasing omega-3s in animal
food products is to feed livestock with fish meal or other marine
products, which is time consuming, costly and limited by the availability
of those feeds."
Investigating a potential novel way further to increase omega-3
consumption, the MGH researchers developed a strain of mice that
have the c. elegans gene fat-1, which codes for an
enzyme that converts omega-6 acids to omega-3s. The transgenic mice
appeared perfectly healthy and were raised, along with normal mice,
on a diet low in omega-3s.
Tissues from the transgenic mice were found to be high in omega-3
fatty acids, while the tissues from normal mice had fats primarily
consisting of omega-6s, as do most mammals. The ability to transmit
fat-1 into mammals without losing its effectiveness or causing
any apparent harm to the transgenic animals raises the possibility
of developing farm animals that naturally produce omega-3 rich food
"The obvious followup to our finding would be to create livestock
animals transgenic for fat-1 and see if their tissues also
contain omega 3s," says Kang, who is an associate professor
of Medicine at Harvard Medical School. "This mouse model also
will be useful in studies to further investigate the impact of the
omega 3/omega 6 ratio on disease prevention and treatment. Another
possibility to explore would be gene therapy to introduce fat-1
directly into human tissue."
Kang's co-authors are Jingdong Wang, MS, and Zhao Kang, MD, MGH
Medicine, and Lin Wu, PhD, MGH Dermatology. The research was supported
by grants from the National Cancer Institute, the American Cancer
Society and the American Institute for Cancer Research.
Massachusetts General Hospital, established in 1811, is the original
and largest teaching hospital of Harvard Medical School. The MGH
conducts the largest hospital-based research program in the United
States, with an annual research budget of more than $350 million
and major research centers in AIDS, cardiovascular research, cancer,
cutaneous biology, medical imaging, neurodegenerative disorders,
transplantation biology and photomedicine. In 1994, MGH and Brigham
and Women's Hospital joined to form Partners HealthCare System,
an integrated health care delivery system comprising the two academic
medical centers, specialty and community hospitals, a network of
physician groups, and nonacute and home health services.
Media Contact: Sue
McGreevey, MGH Public Affairs
Physician Referral Service: 1-800-388-4644
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