Navigation Links
Solving the Medical Mystery of Cold Feet
Date:8/17/2012

By Lisa Esposito
HealthDay Reporter

FRIDAY, Aug. 17 (HealthDay News) -- If you've ever been booted out of bed because of your icy feet, new research may help explain your plight.

Scientists have pinpointed specific proteins within the skin's blood vessels that play a part in the body's reaction to cold stimuli, whether it's exposure to chilly weather or touching a frigid surface with your bare hand.

The body's response to cold is to cut off circulation to the extremities to preserve blood flow to warm the internal organs. But for some people, this response is too strong, or it occurs mistakenly.

In Raynaud's disease, for instance, as the body responds to cold or stress, blood vessels narrow in the fingers and toes, which may feel numb and turn from white to blue to red during an attack.

The researchers wanted to know more about the physiological mechanisms at work. The new study and an accompanying editorial appear in a recent issue of the American Journal of Physiology -- Cell Physiology.

The researchers used muscle cells from tiny blood vessels in skin-punch biopsies from healthy volunteers as well as muscle cells from an artery found in mouse tails with circulation similar to human skin.

"Our bodies are engineered by evolution to conserve heat and energy," explained Dr. Martin Michel, a professor at Johannes Gutenberg University in Germany, and the co-author of the editorial. "One way of doing this is limiting blood flow to the skin by making blood vessels constrict, and norepinephrine (a hormone and neurotransmitter) does this via alpha-adrenergic receptors on muscle cells in the blood vessel wall. But we only want this to happen when it is cold."

For some people, he said, it appears that the healthy reaction goes awry.

"The mechanisms get active at 'normal' outer temperature," Michel said. "This could involve too many alpha-adrenergic receptors or that the [temperature] set-point or something in the regulation mechanism goes wrong. Now we know for certain that two molecules called Epac and Rap1 play an important role in the process."

The study identified new players that influence adrenergic receptor function in small blood vessels, said senior study author Maqsood Chotani, a principal investigator at the Research Institute at Nationwide Children's Hospital in Columbus, Ohio.

"The alpha-2C receptors had been identified many years ago, but the exact function of this alpha-2C subtype in blood vessels was very intriguing to me," Chotani said. "Early observations showed the alpha2C to be inside the cell and not on the cell surface like other receptors in the same family. The general belief [had been] that the receptor doesn't do anything in blood vessels -- it was like a vestigial, or like a silent receptor."

Not so, the study found.

"The alpha-2C receptor has a specialized role; in fact, we believe it is a stress-responsive receptor and in this case it's actually conserving body heat," he said. "So we know how the receptor is regulated in health. In disease -- like Raynaud's -- there could be a dysfunction, there could be overactivity of the new players we have identified in this study."

The U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases describes two levels of Raynaud's.

Primary Raynaud's, which usually starts between the ages of 15 and 25, is seen most often in women and people living in cold places. Preventive measures include keeping hands and feet warm and dry, avoiding air conditioning and wearing gloves to touch frozen or cold food.

Secondary Raynaud's starts later in life and is seen with connective tissue diseases like scleroderma, Sjorgen's syndrome and lupus, according to the NIAMS. Severe cases can lead to tissue death in the fingers and toes.

In secondary Raynaud's, Chotani said, "the underlying cause could be an immune response, and it could be a complicated mixture of responses. Whereas in primary Raynaud's, its underlying cause is really not known."

Now, Michel said, "we can look specifically at whether the newly discovered mediators of blood flow control in the extremities are malfunctioning in such people. If they do, we may find a way to handle this."

And, Chotani said, "in the disease process, the implications for the findings that we have, these new players potentially could be targets for pharmaceutical drugs."

What about people at the other extreme, whose hands and feet always feel hot?

"That's another physiological response of the body trying to open up the blood vessels and just remove the heat from the body, so it doesn't overheat," Chotani said. "The receptor, I would think, is not working. It's just the opposite scenario."

More information

Visit the U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases to learn more about Raynaud's phenomenon.

SOURCES: Maqsood Chotani, Ph.D., Center for Cardiovascular & Pulmonary Research: The Research Institute at Nationwide Children's Hospital, and assistant professor, department of pediatrics, Ohio State University Wexner College of Medicine, Columbus, Ohio; Martin Michel, M.D., professor, department of pharmacology, Johannes Gutenberg University, Mainz, Germany; May 23, 2012, American Journal of Physiology -- Cell Physiology, online


'/>"/>
Copyright©2012 ScoutNews,LLC.
All rights reserved  

Related medicine news :

1. Scientists solving the mystery of human consciousness
2. Grant awarded to help improve problem-solving skills for deaf and hard-of-hearing students
3. Solving the mystery of how cigarette smoking weakens bones
4. Physician Groups Call for Fewer Medical Tests
5. Weill Cornell Medical College establishes Center for Healthcare Informatics and Policy
6. CAM therapy combined with conventional medical care may improve treatment of lower back pain
7. Image share project gives patients and physicians anytime, anywhere access to medical images
8. Researchers determine vitamin D blood level for reducing major medical risks in older adults
9. Biomedical researchers receive Hartwell Foundation awards
10. Columbia University Medical Center and NY-Presbyterian experts at APA meeting
11. Fitness in Middle Age Lowers Medical Costs Later: Study
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Solving the Medical Mystery of Cold Feet
(Date:1/20/2017)... , ... January 20, 2017 , ... Source Vitál Apothecary, ... 100 percent pure essential oils, announced the company had a successful visit to the ... annual ECRM event gives companies that work in the nutritional, sports and health industries ...
(Date:1/20/2017)... ... January 20, 2017 , ... ATP Science, ... everyday lives, recently attended the January ECRM Trade Show in Hilton Head, SC, ... for its large range of supplements that keep the body functioning at its ...
(Date:1/20/2017)... ... January 20, 2017 , ... ... sugar-free alternative VW+ 002. The drinks have been produced in collaboration with Zlatan ... perform during your workout. , After a successful launch in Sweden last year, ...
(Date:1/20/2017)... ... , ... “I Forgive You”: a fine examination of how God handles sin, including how ... published author, Stephen Miller, who, for over ten long years has been waiting to release ... Trinidad and Tobago, he has been serving the Lord for over twenty years, and he ...
(Date:1/20/2017)... ... ... “Knowledge is God’s Lighthouse”: a moving and colorful collection of prayers that reminds ... published author, Gene Gaapf, a retired truck driver, and a long-time writer, whose published ... high school and have many different titles,” Gaapf mentions about his different works. “I ...
Breaking Medicine News(10 mins):
(Date:1/19/2017)... 19, 2017  Abaxis, Inc. (NasdaqGS: ABAX ... instruments and consumables for the medical and veterinary markets ... financial results for the third quarter fiscal year 2017, ... 4:15 p.m. ET on Thursday, January 26, 2017.  The ... fiscal year 2017 after the market closes on Thursday, ...
(Date:1/19/2017)...   Science Exchange , the leading marketplace ... the first five replication studies from the ... in eLife today. Despite intense scrutiny around reproducibility ... evaluation of reproducibility rates that may identify specific ... assessments of reproducibility, the results of this project ...
(Date:1/19/2017)... , January 18, 2017 , , Marks E-QURE ... distribution agreement, following similar agreements in ... Wound care is $2 5 ... E-QURE Corp. (OTCQB: EQUR), a leader in medical devices for the treatment ... - Médica Equipos Médicos S.A.S. (TeckMedica) in Colombia for ...
Breaking Medicine Technology: