Diabetes News
Week of May 7, 2000 |
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Liver Cells Enabled To Produce Insulin
For several years researchers have attempted to transplant
or replace pancreatic tissue in order to correct the body's
failure to produce insulin in people with Type 1 diabetes. An
even more novel technique that researchers are currently
developing is the use of gene transfer therapy, in which cells
already in the body can be "programmed" to produce insulin.
In a recent issue of Nature Medicine, Dr. Sarah Ferber of the
Sheba Medical Center in Tel-Hashomer, Israel, reports on her
studies with this new technique. Dr.Ferber says that the gene
PDX-1 is partly responsible for determining whether or not the pancreas
makes insulin. In studies with diabetic mice, researchers transferred
PDX-1 through a harmless virus, and found that the gene was able
to activate liver cells to produce insulin.
Compared to mice who received the virus alone, those
who'd received PDX-1 had insulin levels in their livers which
were 25 times higher. Blood levels of insulin were three times higher in
the treated mice as well. All of the mice that were treated with
PDX-1 lived through the entire experiment, and also showed
decreasing levels of blood sugar. By contrast, twelve of the
twenty-two untreated mice died shortly after receiving the
untreated virus, and all died within eight days of chemically
induced diabetes.
One advantage of creating insulin-producing cells in the
liver is that this organ is one of the first to encounter
digested glucose as it enters the bloodstream. However, the
liver is also a primary organ involved in releasing glucose
whenever needed by the body during exercise and hypoglycemia.
The very high levels of insulin produced within the liver are
likely to block the body's normal glucose release from the liver
when this is needed. Researchers hope that PDX-1 gene transfer can program other
tissues in the body to produce insulin. The technique is still
very experimental, and has not reached the level of human
testing yet.
Cellular Cloning May Treat Diabetes
Cellular cloning is one of the most controversial
scientific endeavors, with heated arguments both in favor of and
opposed to the technique, even though cloning may be used to treat a variety of
diseases, including diabetes.
Dr. Robert P. Lanza, of Advanced Cell Technologies in
Worcester, Massachusetts, reports on his research with six
cloned calves in a recent issue of Science magazine. These
calves have cells that are much younger than the cells of calves
of the same chronological age. Likewise, the cloned calves have
much longer telomeres (structures at the ends of chromosomes
that shorten with every cell division) than normal calves. When
telomeres reach a shorter length, usually after about 75-80 cell
divisions, the cell dies. This helps the body to dispose of old
tissue.
Researchers cloned these calves by using connective tissue
cells that had only about four divisions left. In the cloned
calves, the telomere length of the cells suggested a possibility
of ninety cellular divisions, showing that young cells can be
created from old ones.
Scientists hope that the creation of young cells through
cloning can treat diseases in humans. One example would be to
clone the cells of a person with diabetes, and form cells that
produce insulin. These functioning cells could then be
reinjected into the person, essentially eliminating the disease.
Creating new cells from a person's own cells would also be
advantageous in that the cells would not be rejected by the
body, as is often the case in transplants from other people's
bodies.
For more information on the latest cloning breakthrough and
its implications for people with diabetes and other diseases,
read an interview with Dr.
Michael West, the President and CEO of Advanced Cell
Technology.
Dental Treatment Prevents Heart Disease?
Tooth decay is not uncommon in people with diabetes, as
elevated blood
sugar levels provide a good environment for bacteria. A new dental treatment may assist in
lowering the incidence of tooth decay and infection, and this
reduction of peridontal disease also may decrease the rate of heart disease.
A study in a recent issue of the Journal of Periodontology
shows the benefits of using a very low dose antibiotic called doxycycline
when treating adult periodontal disease with teeth cleaning and root
planing of the teeth. The low dose antibiotic treatment acts by inhibiting enzymes that
degrade tissue in bacterial infections. If these enzymes go
unchecked, they can destroy collagen in connective tissue,
eventually breaking down the gums, ligaments, and bones. Besides
leading to tooth loss, the chronic inflammation of dental
disease may also lead to
heart disease.
Jack G. Caton, DDS, MS, professor of periodontology at the
University of Rochester's Eastman Dental Center, led a study in
which 190 people with periodontal disease were treated with this
cleaning technique, and then given either 20mg of low dose
doxycycline or a placebo twice
a day. Doxycycline is normally given at 100 mg twice a day for
infections.
Those who were given the antibiotic showed a much greater
improvement in clinical attachment levels and probing depths of
the teeth,
which measure the rate of deterioration of gums, ligaments, and
bones that commonly occur with advanced gum disease. The people
receiving doxycycline also had more tooth sites with
improvements of gum attachment to tooth of 2mm or more, which is
considered a significant improvement.
They experienced fewer areas of rapid tooth disease progression as
well. These improvements persisted throughout the duration of
the study.
Doxycycline is currently on the market, available as Periostat.
Periostat was approved by the FDA in September 1998.
New Blood Test Predicts Heart Disease
Heart disease is a common occurrence in this country, and is
one of the leading causes of death. A new blood test may help to
predict the likelihood of heart disease with even more accuracy
than a cholesterol test.
Researchers at Harvard Medical School describe the test in a
recent issue of the Tufts University Health & Nutrition
Letter. The test measures the body's level of high-sensitivity C-reactive protein (hs-CRP). This protein is
made by the liver, and its presence signifies inflammation in
the body. This is important in diagnosing heart disease because
hardening of the arteries involves inflammation.
Previously, the main test for heart disease was a cholesterol
test. These tests determine how much plaque has built up in the
arteries. The hs-CRP test, by contrast, determines how likely
the plaque is to rupture and release possibly-deadly clots.
The doctors at Harvard conducted a study in which they
compared blood levels of hs-CRP in women who later had heart
attacks, strokes, or bypass surgery to the blood levels of hs-CRP
in women who did not have heart problems. They found a direct
correlation between those with high hs-CRP levels and those who
had heart disease, regardless of their cholesterol levels.
Inflammation has long been suspected of causing heart
disease. Aspirin has long been known to reduce cardiac events.
Aspirin's benefit has been associated with it's blood-thinning
properties, but this may have to be re-evaluated in light of the
benefits seen with reducing inflammation. The hs-CRP test has been approved by the FDA, in conjunction with
cholesterol tests. Conducting the tests together increases the
likelihood that heart disease will be detected, and hopefully
prevented.
Disastrous Diets Cause Obesity
The rate of Type 2 diabetes is on the rise, a fact that is
not surprising in light of recent statistics released by the
Department of Agriculture.
The statistics show that the average American today consumes
about 350 more calories per day than the average American 15
years ago. The average American diet is also much worse, being higher in sugar and carbohydrates. Part of the reason for this is
that more people are eating out more often, with a third of
calories now consumed outside the home. In the 1970s, only about 18%
of calories were consumed outside the home, and restaurants now
serve fattier foods. On average, 38% of calories comes from
fat when eating out, compared to 31.5% of calories when
people eat at home.
The most startling statistic is that 55% of today's Americans are
overweight or obese, putting them at higher risk of developing
diabetes, heart disease, stroke, and high blood pressure.
New Erectile Dysfunction Website
A common complication for men with diabetes is erectile dysfunction. In an effort to create a source of
accurate information about this condition, the American
Foundation for Urologic Disease has created a new Erectile
Dysfunction website.
The internet provides a wealth of information on erectile
dysfunction, though
some of it may be inaccurate. The Foundation has created a site to
dispel the myths, and provide scientific information about the
condition and possible treatments. The site also includes a chat
area that is monitored by a physician, and a confidential
registry so that those with erectile dysfunction may regularly receive treatment
information.
Infectious Diseases Running Rampant
In recent years, wide-spread epidemics of infectious diseases
have become more common. These diseases have also become harder
to fight off, particularly for those with diabetes and other
diseases which may compromise the immune system.
In an editorial in the New England Journal of Medicine (342:
1280-1, 2000), Dr.
Michael Osterholm, of ican Inc. of Eden Prairie, Minnesota,
reports on four recent, but distinctly different outbreaks of infectious
diseases. In the past
25 years, numerous deadly microbes have spread around the world,
including Legionnaires' disease, toxic shock syndrome, AIDS,
rodent-borne hantaviruses, Ebola virus, Lyme disease, "mad
cow" disease (a fatal brain disease), West Nile
encephalitis in the New York City area, and new, drug-resistant
tuberculosis strains.
One of the new reports involved a 12 year old boy with
diabetes in Atlanta who developed an infection of the bowel
called Pigbell after eating chitterlings. Pigbell was first
described in Europeans who ate large meals following long
periods of starvation in World War II, and again later in New
Guinea children who ate large amounts of pork. Pigbell is rarely
seen in developed countries which is a blessing due to its very
high mortality rate. The boy survived following surgical
resection of his bowel.
There are a variety of reasons for the increasingly powerful
infectious diseases, not the least of which is the trend toward
globalization. People are increasingly traveling
internationally, and food is more frequently shipped
internationally. There have also been changes in the way food is
grown and handled with incresing use of antibiotics both
in people and in livestock, so that germs have become more
resistant. Also, due to improved health care, more people are
alive with conditions that compromise their immune systems, including diabetes, cancer,
AIDS, and transplants.
The benefits of globalization, however, include the
accessibility of the latest information on recognizing and
preventing infectious diseases. Helpful websites include those
created by the Centers
for Disease Control, or CDC, and the
World
Health Organization.
Lawsuit Over Insulin
Patent
The Danish company Novo Nordisk has recently filed a complaint against Avantis for patent
infringement. The suit states that the long-acting insulin
Lantus, developed by Avantis, infringes on two German patents
already held by Novo Nordisk. The complaint has been filed with
the Court of Dusseldorf in Germany.
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