Some Germs Are Good for You: Surface Bacteria Maintain Skin's Healthy Balance

On the skin's surface, bacteria are abundant, diverse and constant, but inflammation is undesirable. Research at the University of California, San Diego School of Medicine now shows that the normal bacteria living on the skin surface trigger a pathway that prevents excessive inflammation after injury.

"These germs are actually good for us," said Richard L. Gallo, MD, PhD, professor of medicine and pediatrics, chief of UCSD's Division of Dermatology and the Dermatology section of the Veterans Affairs San Diego Healthcare System.

The study, to be published in the advance on-line edition of Nature Medicine on November 22, was done in mice and in human cell cultures, primarily performed by post-doctoral fellow Yu Ping Lai .

"The exciting implications of Dr. Lai's work is that it provides a molecular basis to understand the 'hygiene hypothesis' and has uncovered elements of the wound repair response that were previously unknown. This may help us devise new therapeutic approaches for inflammatory skin diseases," said Gallo.

The so-called "hygiene hypothesis," first introduced in the late 1980s, suggests that a lack of early childhood exposure to infectious agents and microorganisms increases an individuals susceptibility to disease by changing how the immune system reacts to such "bacterial invaders." The hypothesis was first developed to explain why allergies like hay fever and eczema were less common in children from large families, who were presumably exposed to more infectious agents than others. It is also used to explain the higher incidence of allergic diseases in industrialized countries.

The skin's normal microflora -- the microscopic and usually harmless bacteria that live on the skin -- includes certain staphylococcal bacterial species that will induce an inflammatory response when they are introduced below the skin's surface, but do not initiate inflammation when present on the epidermis, or outer layer of skin.

In this study, Lai, Gallo and colleagues reveal a previously unknown mechanism by which a product of staphylococci inhibits skin inflammation. Such inhibition is mediated by a molecule called staphylococcal lipoteichoic acid (LTA) which acts on keratinocytes -- the primary cell types found on the epidermis.

The researchers also found that Toll-like receptor 3 (TLR3) activation is required for normal inflammation after skin injury.

"Keratinocytes require TLR3 to mount a normal inflammatory response to injury, and this response is kept from becoming too aggressive by staphylococcal LTA," said Gallo. "To our knowledge, these findings show for the first time that the skin epithelium requires TLR3 for normal inflammation after wounding and that the microflora helps to modulate this response."

Additional contributors to the paper include Yuping Lai, Anna Di Nardo, Teruaki Nakatsuji, Anna L Cogen, Chun-Ming Huang and Katherine A. Radek, UCSD Division of Dermatology and the VA San Diego Healthcare System; Anke Leichtle and Allen F. Ryan, UCSD Department of Surgery/Otolaryngology and the VA San Diego Healthcare System; Yan Yang and Zi-Rong Wu, School of Life Science, East China Normal University, Shanghai; Lora V Hooper, Howard Hughes Medical Institute and University of Texas Southwestern Medical Center, Dallas; and Richard R Schmidt and Sonja von Aulock, University of Konstanz, Germany.

The study was funded by grants from the National Institutes of Health, and a US Veterans Administration Merit Award.

Courtesy: ScienceDaily

Can Meditation Curb Heart Attacks?

When Julia Banks was almost 70, she took up transcendental meditation. She had clogged arteries, high blood pressure and too much weight around the middle, and she enrolled in a clinical trial testing the benefits of meditation.

Now Mrs. Banks, 79, of Milwaukee, meditates twice a day, every day, for 20 minutes each time, setting aside what she calls “a little time for myself.”

“You never think you’ve got that time to spare, but you take that time for yourself and you get the relaxation you need,” said Mrs. Banks, who survived a major heart attack and a lengthy hospitalization after coronary artery bypass surgery six years ago.

“You have things on your mind, but you just blot it out and do the meditation, and you find yourself being more graceful in your own life,” she said. “You find out problems you thought you had don’t exist — they were just things you focused on.”

Could the mental relaxation have real physiological benefits? For Mrs. Banks, the study suggests, it may have. She has gotten her blood pressure under control, though she still takes medication for it, and has lost about 75 pounds.

Findings from the study were presented this week at an American Heart Association meeting in Orlando, Fla. They suggest that transcendental meditation may have real therapeutic value for high-risk people, like Mrs. Banks, with established coronary artery disease.

After following about 200 patients for an average of five years, researchers said, the high-risk patients who meditated cut their risk of heart attacks, strokes and deaths from all causes roughly in half compared with a group of similar patients who were given more conventional education about healthy diet and lifestyle.

Among the roughly 100 patients who meditated, there were 20 heart attacks, strokes and deaths; in the comparison group, there were 32. The meditators tended to remain disease-free longer and also reduced their systolic blood pressure by five millimeters of mercury, on average.

“We found reduced blood pressure that was significant – that was probably one important mediator,” said Dr. Robert Schneider, director of the Institute for Natural Medicine and Prevention, a research institute based at the Maharishi University of Management in Fairfield, Iowa, who presented the findings. The study was conducted at the Medical College of Wisconsin in Milwaukee, in collaboration with the institute.

An earlier study of high-risk Milwaukee residents, many of them overweight or obese, also found transcendental meditation, along with conventional medications, could help reduce blood pressure. Most of those in the study had only high-school educations or less, about 40 percent smoked and roughly half had incomes of less than $10,000 a year.

The participants found transcendental meditation easy to learn and practice, Dr. Schneider said.

“Fortunately, it does not require any particular education and doesn’t conflict with lifestyle philosophy or beliefs; it’s a straightforward technique for getting deep rest to the mind and body,” he said, adding that he believes the technique “helps to reset the body’s own self-repair and homeostatic mechanism.”

Dr. Schneider said other benefits of meditation might follow from stress reduction, which could cause changes in the brain that cut stress hormones like cortisol and dampen the inflammatory processes associated with atherosclerosis.

“What is it about stress that causes cardiovascular disease?” said Dr. Theodore Kotchen, associate dean for clinical research at the Medical College of Wisconsin. “Hormones, neural hormones, cortisol, catecholamines — all tend to be elevated in stress. Could they in some way be contributing to cardiovascular disease? Could a reduction in these hormones with meditation be contributing to reduction in disease? We can only speculate.”

Another recent study focusing on transcendental meditation, published in The American Journal of Hypertension, focused on a young healthy population. It found that stressed-out college students improved their mood through T.M., and those at risk for hypertension were able to reduce their blood pressure. Dr. Schneider was also involved in that study, which was carried out at American University in Washington and included 298 students randomly assigned to either a meditation group or a waiting list.

Students who were at risk of hypertension and practiced meditation reduced systolic blood pressure by 6.3 millimeters of mercury and their diastolic pressure by 4 millimeters of mercury on average.

Courtesy:Newyork times