Large doses of alcohol in rats changed brain responses to glucose and insulin metabolism, suggesting a mechanism linking binge drinking with type 2 diabetes. Also this week: blue light as an antiseptic.
Beer Goggles Blur Brain's View of Glucose
Binge drinking may contribute to type 2 diabetes because it distorts the brain's perception of glucose, an animal study suggested.
Rats given large alcohol doses to simulate a 3-day bender developed abnormal brain responses to glucose and insulin resistance, which hung around for days after the booze wore off.
The problem wasn't with the liver, the researchers reported in Science Translational Medicine. Rather, inflammation in the hypothalamus was disrupting insulin receptor signaling in the brain.
"If these results apply to humans, binge drinking is not only an epidemiological risk factor but also a direct cause of insulin resistance that sets the stage for the metabolic syndrome and type 2 diabetes," Christoph Buettner, MD, PhD, of Mount Sinai Hospital in New York City, and colleagues wrote.
-- Crystal Phend
Light Therapy Shows Promise for Burn Wound Infections
Blue light therapy may provide an alternative to antibiotics for treating potentially lethal infections in burn wounds, a mouse study showed.
Blue light in the visible spectrum is known to have antimicrobial effects, but its effectiveness for treating wound infections has not been proven.
Michael Hamblin, PhD, of Massachusetts General Hospital in Boston, and colleagues, conducted both in vitro and in vivo studies to test its ability to eradicate Pseudomonas aeruginosa, a pathogen that often resists conventional therapies.
As reported in Antimicrobial Agents and Chemotherapy, blue light inactivated the bacteria in cell culture by creating intracellular damage.
Then, in mice with burn wounds, a single exposure of blue light applied a half hour after bacterial inoculation significantly reduced the burden of P. aeruginosa without damaging the surrounding the skin. All of the treated mice survived, whereas those with untreated burns died at a rate of 82%.
"The study may serve as an initial effort in the pursuit of utilizing a novel therapeutic option ... for wound infections, especially those caused by multidrug-resistant bacteria," the authors wrote.
-- Todd Neale
Retinoid Blocks Blood Vessel Inflammation
A synthetic retinoid approved in Japan for leukemia treatment may also help in vasculitis, a mouse study suggested.
Vasculitis results from infiltration of inflammatory cells into blood vessel walls, with structural damage to various tissues thought to result from activation of neutrophils. Among retinoids' many effects is blockade of neutrophil activation.
With this in mind, researchers led by Toshihiro Nanki, MD, PhD, of Tokyo University, administered the retinoid agent Am80 to mice with induced coronary vasculitis for 35 days. They found significant depletion of activated neutrophils, reductions in inflammatory cells in the coronary arteries and aortic root, and significant decreases in vasculitis scores.
Writing in Arthritis & Rheumatism, the researchers called for further studies to explore the effects of Am80 on neutrophils from patients with vasculitis. Clinically, such a drug could become an option for patients who don't respond to conventional therapies such as corticosteroids and immunosuppressants.
-- Nancy Walsh
Why Owls Don't Have Whiplash Injuries
Owls have four bone and vascular adaptions that allow them to rapidly rotate their heads in a way that would kill most humans, researchers found.
Using CT angiography imaging on owls that died from natural causes, interventional neuroradiologist Philippe Gailloud, MD, of Johns Hopkins University School of Medicine, and colleagues found that as they turned the owls' heads, the internal carotid arteries grew larger and larger, eventually pooling the contrast dye in reservoirs.
The pooled "blood" would then continue to feed the brain even if one route is blocked during extreme neck rotation through a supporting vascular network that includes small vessel connections between the carotid and vertebral arteries, an adaptation not seen in humans, according to the researchers, whose prize-winning poster appeared in the Feb. 1 issue of Science.
Anatomically, the bony cavities in the owls' neck vertebrae are 10 times larger in diameter than the carotid arteries that pass through them, which "creates a set of cushioning air pockets that allow the artery to move around when twisted," according to a statement from the authors. In contrast, human vertebral arteries fit snugly in the bony holes, or transverse foraminae.
-- Chris Kaiser