Impacts of CIHR-funded research: Diabetes
Diabetes linked to depression
Evidence shows depression contributes to development of type 2 diabetes
Overview
It's reasonable to think that suffering from a chronic disease could lead to depression. But according to the University of Alberta's Dr. Jeffrey Johnson and his colleagues on the Alliance for Canadian Health Outcomes Research in Diabetes (ACHORD), the evidence actually shows the opposite – that depression may contribute to the earlier onset of type 2 diabetes in people who are susceptible. In fact, younger patients with type 2 diabetes were 23% more likely to have experienced on or more depressive episodes before they developed diabetes, compared to a control group. Dr. Johnson and his colleagues hypothesize that depression could result in behaviours such as weight gain, less physical activity and higher rates of smoking or alcohol abuse, all of which contribute to the development of type 2 diabetes. On the other hand, people with type 2 diabetes, after five years, were no more likely to have developed depression than those without the disease.
Impact
Physicians can now help patients suffering from depression avoid the behaviours that could lead them to develop type 2 diabetes.
First Published
CIHR Institute of Nutrition, Metabolism and Diabetes, INMD Update, January 2006
Aerobics? Weights?
It's not either/or; both work better together
Overview
More than two million Canadians have diabetes, and 90% of them have type 2 diabetes. Regular exercise can help to manage type 2 diabetes, but what kind of exercise is best? Dr. Ron Sigal from the University of Calgary and Dr. Glen Kenny from the University of Ottawa led the DARE (Diabetes Aerobic and Resistance Exercise) randomized control trial to determine the impact of aerobic exercise, resistance exercise or a combination of the two. They found that, while both forms of exercise improved glycemic control, combining the two outweighed the benefits of either.
Impact
People seeking to manage their type 2 diabetes with exercise now know that, for best results, they should combine aerobic and resistance exercise.
First Published
CIHR Institute of Nutrition, Metabolism and Diabetes, INMD Update, October 2007
Traditional approaches to diabetes
Cree healers and elders help to identify potential treatments
Overview
Among the Cree of northern Quebec, the prevalence of diabetes has increased from 4.1% in 1989 to 12.5% in 2002. Dr. Pierre Haddad of the University of Montreal has worked with Cree healers and elders to identify plants that have traditionally been used to relives symptoms of diabetes. This marriage of traditional medicine with modern science is a novel approach to relieving the burden of diabetes in this affected population. He and his team have studied more than ten medicinal plants from the Boreal forest, including the inner bark of the balsam poplar, the leaves of the creeping snowberry and the needles of the white spruce. A priority ranking of the medicinal plants studied, based on the scientific evidence, corresponded "strikingly well" with the plants most respected by elders.
Impact
Clinical studies are now underway in one Cree community using traditional medicine to treat diabetes.
First Published
CIHR Health Research Results, 2003-04; updated 2009
A case of nerves
Potential new cure for type 1 diabetes?
Overview
Malfunctioning pain nerves may play a role in type 1 diabetes, according to research by Drs. Hans-Michael Dosch and Michael Salter of the Hospital for Sick Children, University of Toronto. They have found that faulty nerve cells don't produce enough of a hormone called substance P, which affects the amount of insulin produced and the way it works. The result is chronic stress for islet cells, which then die, triggering an immune response that further damages the surviving islet cells. Injecting substance P into mice stopped the inflammation and cured the diabetes for weeks to months. Subsequent research has found that substance P may also be effective against type 2 diabetes.
Impact
Research is ongoing in this area. The researchers are seeking regulatory approval and funding for clinical trials in humans, with trials for type 2 diabetes likely to start sooner than those in people with type 1 diabetes.
First Published
CIHR Canadian Research, International Impact, 2007; updated 2009
Getting to the heart of the matter
Preventing cardiovascular disease deaths in people with diabetes
Overview
Some 80% of people with diabetes die from cardiovascular disease. High levels of sugar in their blood cause fat cells to accumulate on blood vessel walls. Dr. Geoffrey Werstuck of McMaster University has discovered that a molecule called valproate can reduce levels of glucose in the blood and lessen fat accumulation in the cells lining blood vessel walls.
Impact
Researchers have since discovered that valproate inhibits the enzyme glycogen synthase kinase (GSK)-3. Because valproate has side effects in humans, Dr. Werstuck and his team have developed a screening procedure to identify new and better GSK-3 inhibitors and testing them in mouse models of cardiovascular disease.
First Published
CIHR Health Research Results, 2004-05; updated 2009
Developing better treatments for type 1 diabetes
Canadian researchers perfecting islet cell transplant, taking basic research to the bedside
Overview
In type 1 diabetes, the body's own immune system destroys insulin-producing cells in the pancreas, resulting in little or no insulin production. People with type 1 diabetes overcome this inability to produce insulin by injecting an artificial form of insulin, often several times each day. Dr. Ray Rajotte of the University of Alberta has carried out pioneering work in islet cell transplantation to overcome the need for daily injections. He helped to create the Edmonton Protocol, a revolutionary procedure for transplanting normal, insulin-producing islet cells into a person suffering from type 1 diabetes. Now, Dr. Rajotte and his team are trying to address two major problems: trying to eliminate the need for continuous immunosuppressive drugs (which protect the islets from immune system attacks); and working to develop an unlimited supply of islet cells. In Canada, 400 pancreases are donated each year, while there are more than 6,000 people diagnosed with type 1 diabetes each year. A new First Published of islet cells, therefore, is needed. Dr. Rajotte and his team are working with colleagues internationally on using islet cells from neonatal pigs as a possible solution to the shortage of donor pancreases.
Impact
Since the Edmonton Protocol was first developed, in 2000, 160 patients have received islet cell transplantation in Edmonton. Fifty centres worldwide are offering islet cell transplantation based on the Edmonton Protocol; they have treated another 600-700 patients. Islet cells from neonatal pigs have succeeded in curing diabetic monkeys for up to one year and Dr. Rajotte and his colleagues are trying to establish human clinical trials to test the cells in humans. As well, in November 2007, the Alberta Diabetes Institute, largest free-standing diabetes research institute in North America, opened at the University of Alberta. The Institute will house more than 40 scientists, along with graduate students, research fellows and technicians – all told, in excess of 400 people working in all aspects of both type 1 and type 2 diabetes research. The institute is a direct result of the work on islet cell transplantation carried out in Edmonton.
First Published
CIHR Health Research Results, 2006-07 (among others); updated 2009
Easing diabetes pain with insulin
Benefits may go beyond blood sugar
Overview
People with diabetes often develop a condition known as diabetic neuropathy, in which nerve cells in the skin begin to die off, resulting in pain. Dr. Douglas Zochodne of the University of Calgary has discovered that insulin, already used by people with diabetes to maintain their blood sugar levels, may also boost nerve growth and help stop pain.
Impact
A human trial of intranasal insulin for diabetic neuropathy is in the planning stages, awaiting ethical approval from the University of Calgary.
First Published
CIHR Health Research Results, 2006-07; updated 2009
Prevent heart disease, save money
It's a win-win all around
Overview
So-called water pills, or diuretics, are inexpensive alternatives to newer, more expensive drugs, but just as effective at preventing a heart attack or heart disease in people with diabetes. Dr. Frans Leenen of the University of Ottawa Heart Institute was the Canadian lead on a joint Canadian-US study that also found that duretics were better for treating most people with blood pressure problems. The need to control blood pressure is especially urgent for people with diabetes.
Impact
Since publication of these findings, guidelines for treating hypertensive patients with diabetes now recommend the use of diuretics as the first line of treatment. Several studies in the United States and Canada over the past decade have shown a reversal of the downward trend in the use of diuretics.
First Published
CIHR Health Research Results, 2004-05; updated 2009
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