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Archive - 04 - 2010

Less is More When Restraining Calories Boosts Immunity

Posted by dlife on Thu, Apr 29, 10, 11:03 AM 0 Comment

April 29, 2010 (EurekAlert) - Scientists funded by the Agricultural Research Service (ARS) found that volunteers who followed a low-calorie diet or a very low-calorie diet not only lost weight, but also significantly enhanced their immune response. The study may be the first to demonstrate the interaction between calorie restriction and immune markers among humans.

The lead researcher, Simin Nikbin Meydani, is director of the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University in Boston, Mass., and also of the HNRCA's Nutritional Immunology Laboratory.

The study is part of the "Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy" trial conducted at the HNRCA. As people age, their immune response generally declines. Calorie restriction has been shown to boost these immune responses in animal models.

In the study, 46 overweight (but not obese) men and women aged 20 to 40 years were required to consume either a 30-percent or 10-percent calorie-restricted diet for six months.

Prior to being randomly assigned to one of the two groups, each volunteer participated in an initial 6-week period during which measures of all baseline study outcomes were obtained. All food was provided to participants.

For the study, the researchers looked at specific biologic markers. A skin test used called DTH (delayed-type hypersensitivity) is a measure of immune response at the whole body level.

The researchers also examined effects of calorie restriction on function of T-cells--a major type of white blood cell--and other factors on the volunteer's immune system.

DTH and T-cell response indicate the strength of cell-mediated immunity. One positive was that DTH and T-cell proliferative response were significantly increased in both calorie-restrained groups.

These results show for the first time that short-term calorie restriction for six months in humans improves the function of T-cells.

Better Vision Ahead for Many Diabetic Retinopathy Patients

Posted by dlife on Tue, Apr 27, 10, 01:14 PM 0 Comment

April 27, 2010 (EurekAlert) - A nationwide, government-sponsored study finds that people with a common form of diabetic retinopathy can benefit from a medication first developed to combat another potentially blinding disease, age-related macular degeneration (AMD). Treating diabetic macular edema (DME) with ranibizumab (Lucentis) eye injections, plus laser treatment if needed, appears to result in better vision than laser treatment alone, according to the Diabetic Retinopathy Clinical Research (DRCR) Network study published today in Ophthalmology online, the journal of the American Academy of Ophthalmology (Academy). DME is the main cause of vision loss in people with diabetes mellitus.

At the one year follow-up, nearly 50% of study patients who received the new combined treatment had substantial improvement in vision, compared with 28% who received laser treatment alone. Laser treatment has been the standard of care for DME for 25 years.

"The results appear to be applicable to most people who have DME in the center of the macula with some vision loss, whether the person has Type 1 or Type 2 diabetes, is old or young, or is a woman or a man," said Neil M. Bressler, MD, the Chair of the nationwide DRCR Network, and Chief of the Retina Division, Wilmer Eye Institute, Johns Hopkins University School of Medicine.

"This is a seminal study of which ophthalmology should be very proud," said George A. Williams, MD, an Academy board member and Ophthalmology Department Chair, Oakland University William Beaumont School of Medicine. "First and most importantly, it provides patients an improved therapy for diabetic macular edema. Second, the DRCR Network study is the first multi-center, randomized clinical trial to show how ranibizumab and the laser work together to improve treatment."

The DRCR Network investigators studied 854 eyes (691 participants) at 52 clinical centers across the United States, and compared four treatment modalities: ranibizumab plus prompt laser treatment, ranibizumab plus deferred laser treatment (provided at 24 weeks or later, if indicated), a coritcosteroid (triamcinolone) eye injection plus prompt laser treatment, or prompt laser treatment alone.

At the one year follow up patients who had received ranibizumab with prompt or deferred laser treatment had, on average, significantly better visual acuity than the group treated with laser alone. Also, significantly more patients in the ranibizumab-treated groups gained vision, and fewer suffered vision loss. In patients who entered the study after having cataract surgery and lens implants, results for corticosteroids plus laser treatment appeared comparable to the ranibizumab results, but intraocular pressure (IOP) increased in some corticosteroid-treated patients. Elevated IOP is undesirable because it can increase the risk of glaucoma. Negative outcomes were minimal in patients treated with ranibizumab. Results at two years were comparable to year one, but the researchers urge further study to confirm the longer-term safety and effects of ranibizumab for diabetic macular edema patients.

"In the brave new world of health care reform, the DRCR Network will serve as a model for future comparative effectiveness studies," Dr. Williams said.

The Academy will review the DRCR Network results and recommendations to determine whether, going forward, ranibizumab plus laser treatment should be a preferred treatment for most patients with diabetic macular edema with characteristics similar to those enrolled in this DRCR Network study.

Drs. Bressler and Williams emphasize that people with diabetes should ask their ophthalmologists (Eye M.D.s) if the new treatment approach might be appropriate for them. Although ranibizumab is an FDA-approved drug for AMD, it is not yet specifically approved for use with DME. Not every insurance company covers its use for DME at this time, since the definitive DRCR Network study results have just been published, although some insurance companies currently do cover this use based on previous smaller studies with briefer follow-up. Also, the DRCR Network study did not evaluate a very similar drug, bevacizumab (Avastin), so definitive confirmation of its potential effectiveness in DME is not yet available.

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