Every month we read many medical articles so that we can share with you what researchers are writing about in esteemed medical journals. We thank you for letting us know the subjects you are interested in and so we continue to report on these subjects. Those of you who have not e-mailed us with your interests, feel free to do so. We'll do our best for you. Please read on and feel free to reread past research from the years that we have been publishing this monthly magazine. At the beginning of each article we tell you what we include that month so it's easy to find articles that will be of interest. Read on.
This month we have articles on popular subjects that include cardiovascular effects of sildenfil during exercise in men with coronary heart disease, a new heart disease test that will work for women as well as men, heart risk after stopping statins, an antigen-specific approach that may prevent type 1 diabetes, and finally the benefits of combination therapy in type 2 diabetes.
We start with the following from the Mayo Clinic Proceedings of February, which highlighted the benefits of diet and physical activity. The article urges all physicians and policy makers to develop strategies to help patients meet diet and exercise goals. Sound familiar? Dr. Booth and his team from Missouri as well as Dr. Kottle from the Mayo Clinic and Dr. Pinto from Rhode Island collected the data for the three research papers that are the basis for this report. Dr. Pinto's research was done with women who were undergoing treatment for cancer. The results for these women agreed with those for the respondents of the other two research projects who did not have this problem. The results of all of the papers indicated hat exercise and diet can help people to live longer, healthier lives as well as enhance the quality of life in a society where obesity is a major medical problem. Those of us on a healthy diabetic diet know the benefits of eating in a healthy manner. Now we need to get the rest of our friends and the physicians and insurance companies to reconsider our daily exercise and eating habits.
Our first article is titled Cardiovascular effects of sildenafil during exercise in men with known or probable coronary artery disease by Adelaide M. Arruda-Olson, MD, Ph.D. et al in Feb.13, 2002 issue of JAMA. In this prospective, randomized, double-blind crossover study in men with erectile dysfunction and known or probable coronary heart disease, sildenafil administered 1 hour before maximal, symptom-limited exercise testing was well tolerated and did not change the on-set, extent, or severity of ischemia, as assessed by exercise electrocardiography or echocardiography. Risk factors for erectile dysfunction and coronary heart disease are similar and include diabetes mellitus, hypertension and smoking. This is the first report to describe exercise testing with sildenafil monitored by both electrocardiography and imaging techniques. The conclusions of the research are good news. In men who had known or probable coronary heart disease and who were able to exercise, sildenafil had no effect on the presence or extent of exercise-induced regional wall motion abnormalities, symptoms, or arrhythmias. In patients who had stable coronary artery disease and were not taking nitrates, sildenafil did not potentiate myocardial ischemia. Good information to take to your physician if you are considering getting help for erectile dysfunction.
Our second article is from Circulation 2002;10.1161/he 112.105565 and is written by Dr. Jee-Young Oh et al at the University of California San Diego. The latest experimental blood test examining levels of proinsulin, which is a precursor to the hormone insulin, was examined. It is known that in men, high levels of insulin are associated with atherosclerosis, which can lead to heart attack or stroke. The researchers wanted to know if the same test could be used to predict this risk in women. In both men and women, high levels of proinsulin approximately doubles the risk of heat disease. This was true even after the team accounted for the other heart disease risk factors of age, weight and blood pressure. They concluded that "measurement of proinsulin might help identify patients who have coronary disease or who are at high risk for developing coronary disease." They also called for further research to draw out the differences between proinsulin and insulin in their ability to identify men and women with heart disease.
One more article on heart disease for this month. We include this because of the high incidence of heart disease with diabetes. This one also from Circulation examines the heart risk after stopping statins. If you read our What's Hot articles and these research abstracts, you know the benefits of taking statins, so this article was of special interest. This article is based on 1,600 coronary disease patients in the Kerckoff Heart Center in Bad Nauheim, Germany and was done by Christian Hamm for Merck Research Laboratory. Patients were given the right to continue or discontinue taking statins while hospitalized. Those who continued to take these cholesterol lowering medications were less likely to have a heart attack within the first 30 days after being hospitalized. Compared to those who stayed on stains, those who stopped had a nearly triple risk of heart attack or death. They were also 70% more likely to have a heart attack or die than those who had never taken statins. The authors conclude that although the medications were designed to lower cholesterol, they have additional benefits in patients with acute coronary syndrome. It is thought that they improve the function of arteries in these people by boosting the release of a substance called nitric oxide. In view of these results, do talk to your physician about any thought of stopping using statins.
Reuters has reported on an article in Nature Immunology for April published online Feb. 25th. that a soluble dimeric peptide-major histocompatibility complex chimera, dubbed DEF, is available to prevent the onset of type 1 diabetes in transgenic mice prone to the disease. In mice that are already diabetic, DEF restores normoglycemia. Dr. Sofia Casares of Mount Sinai School of Medicine in New York and colleagues describe DEF as being constructed on an immunoglobulin scaffold, and able to bind to cognate T cells. The complex exhibits a half-life in circulating blood of 50 hours. Ten of 12 mice who were given DEF every 5 days resisted diabetes onset for the 4.5 month treatment period, while the control mice developed massive intra-islet infiltration and lost the ability to produce insulin in most of the islets within the first 10 weeks. When DEF was interrupted, it took only about 15 days for diabetes to then develop. If mice were treated with DEF as soon as hyperglycemia set in, normal glycemic levels were restored within 2 days in nine of 16 mice, lasting up to 8 days. Long-term normoglycemia could be maintained with periodic DEF treatment. If injections were delayed until 2 weeks after hyperglycemia had developed, however, treatment was ineffective. The investigators found that auto reactive CD4+ T cells in the mice's spleens became anergic upon exposure to DEF. These T cells were impaired in their ability to migrate to the pancreas. T cells already in the pancreas were stimulated by DEF to secrete interleukin-10, which provides some protection from diabetes, perhaps by down-regulating diabetogenic T cells in the peripheral lymphoid organs. Dr. Casares' group concludes "It may be possible to use this antigen-specific approach in the prevention and treatment of type 1 diabetes." Keep tuned and we'll continue to share any other research that may foretell how we will find a cure and prevent diabetes.
Our last article comes from Diabetes Care 2002;25:330-336, 395-396 and is titled Combination therapy helpful in type 2 diabetes by Dr. Carole A Cull et al from Great Britain. Her group reports that prompt addition of insulin is effective in patients with type 2 diabetes which is inadequately controlled by sulfonylures alone. In fact, the researchers found that "combinations of treatments will be required routinely to enable people with type 2 diabetes to reach target levels of glycemic control."
To evaluate approaches of management of diabetes, over a 6-year period Dr. Cull and her group at the University of Oxford followed 826 patients with newly-diagnosed type 2 diabetes. Of these 242 were randomized to therapy primarily focused on diet, 245 were given insulin alone, and 339 to sulfonylurea with insulin if needed. Subjects in this group were automatically given insulin when their fasting plasma glucose rose above 6.0 mmol/L or 108 mg/dl.
About 53% of these sulfonylurea patients received insulin therapy. Overall, median glycosylated hemoglobin (HbA1c) in the combination group (6.6%) was significantly lower than in patients on insulin alone. Furthermore, 47% of combination patients had a HbA1c below 7% versus 35% of patients on insulin alone. Weight was similar in the combination group and insulin alone groups, but the annual rate of major hypoglycemia in combination patients (1.6%) was significantly lower than in those receiving insulin alone (3.2%).
Dr. Cull concludes that adding insulin to sulfonylurea improves glycemic control without promoting weight gain nor increasing hypoglycemia unacceptably. She suggests that physicians consider adding insulin early in treatment if needed and should be considered as an alternative to the addition of other oral agents.
BSP
