Regular exercise could reduce complications of sickle cell traitApril 26, 2012
SAN DIEGO-Sickle cell disease (SCD), an inherited condition that causes red blood cells to sometimes deform into a crescent shape, affects an estimated 100,000 Americans, typically those of African descent. However, far more have sickle cell trait (SCT), caused when individuals carry just a single copy of the disease-causing mutation in their genes. Rather than all their red blood cells being affected, those with SCT carry a mix of affected red blood cells and normal ones. Previously, researchers and physicians had assumed that those with SCT were immune from the increased burden of sickness and death that those with SCD carry. However, recent research suggests that the same morbidity and mortality that follow SCD patients at an increased rate also affect those with SCT to a lesser extent.
Nearly all these adverse effects are consequences of oxidative stress, a condition in which free radicals overwhelm the body's natural antioxidants. In healthy individuals, oxidative stress has been linked with conditions including cancer, heart disease, and simply aging; in sickle cell disease patients, oxidative stress is thought to play a role in causing the inflammation, problem with the linings of blood vessels, and blood cell blockages that cause complications from this disease.
However, scientists have long known that exercise increases the level of antioxidants present in the body, defending against oxidative stress. In a new study, researchers compare the effects of exhaustive exercise on people with SCT who exercise regularly with those who don't. They found that training regularly seems to offset the burden of exhaustive exercise by lowering the levels of molecules associated with oxidative stress, increasing antioxidant molecules, and increasing nitric oxide, a molecule important for opening blood vessels which could play a role in preventing the blood vessel occlusion that sometimes occurs in SCD and SCT.
The study is the result of efforts undertaken by Vincent Pialoux, Erica N. Chirico, Camille Faes, Emeline Aufradet, and Cyril Martin of the University Lyon I, Leonard Feasson of the University of Saint-Etienne, and Laurent Messonnier of the University of Savoie. An abstract of their study entitled, "Physical Activity Blunts Oxidative Stress Reponse to Exercise in Sickle Cell Trait Carriers," will be discussed at the meeting Experimental Biology 2012, being held April 21-25 at the San Diego Convention Center. The abstract is sponsored by the American Physiological Society (APS), one of six scientific societies sponsoring the conference which last year attracted some 14,000 attendees.
Training Reduces Oxidative Stress
Dr. Pialoux, who led the study, and his French colleagues collaborated with colleagues at the University of Yaounde I in Yaounde, Cameroon, where the rate of SCD and SCT is significantly higher than in France. The researchers recruited 18 volunteers with SCT and 22 others without this trait. Each group was further subdivided into those who had exercised consistently for several years by playing soccer for at least eight hours per week and those who considered themselves sedentary for at least the last two years.
Each volunteer's blood was tested for the presence of molecules that signal oxidative stress, others that act as antioxidants, and nitric oxide metabolites. These volunteers then pedaled on a stationary bicycle, with the researchers ratcheting up the workout's intensity every few minutes until the volunteers bowed out from exhaustion. After the workout, the researchers tested the volunteers' blood again at regular intervals to assess the same molecules.
Results showed that well-trained volunteers with SCT had significantly lower levels of molecules associated with oxidative stress, higher levels of antioxidant molecules, and higher levels of nitric oxide metabolites than untrained volunteers with SCT.
Results Could Apply to SCD
These results suggest that regular exercise might help combat the problems likely caused by oxidative stress that increase morbidity and mortality in people with SCT, Pialoux says. "In this population, regular physical activity might be seen as a treatment," he adds.
The findings could hold promise for patients with SCD as well, he says. Since exercise is known to trigger the painful and damaging episodes known as sickle cell crisis, in which large red blood cells become sickled and block blood vessels, doctors often advise SCD patients to avoid exercise. However, if these patients exercise regularly and become trained over time, the associated reduction in oxidative stress might improve their condition, Pialoux explains.
"We think that regular physical exercise that's controlled by a physician and performed at low intensity could be a strategy to limit the disease burden in SCD patients," he says. He and his colleagues are currently testing this strategy in animal models of the disease, with plans to eventually test human subjects.
Federation of American Societies for Experimental Biology
Related Oxidative Stress Current Events and Oxidative Stress News Articles
UTMB study uncovers mechanism responsible for pollen-induced allergies
A new study from The University of Texas Medical Branch at Galveston has uncovered a mechanism that is central to becoming allergic to ragweed pollen and developing allergic asthma or seasonal nasal allergies.
Blood vessels can actually get better with age
Although the causes of many age-related diseases remain unknown, oxidative stress is thought to be the main culprit.
New study: Tart cherry juice reduced post-race respiratory tract symptoms after a marathon
While previous research suggests tart cherry juice may help aid muscle recovery after extensive exercise, a new pilot study published in the Journal of the International Society of Sports Nutrition found that Montmorency tart cherry juice reduced upper respiratory tract symptoms associated with marathon running in study participants.
What is the role of the gut microbiome in developing Parkinson's disease?
In recent years, an important Parkinson's disease (PD) research focus has been on gut-related pathology, pathophysiology, and symptoms. Gastrointestinal dysfunction, in particular constipation, affects up to 80% of PD patients and idiopathic constipation is one of the strongest risk-factors for PD.
Scientists show antitumor agent can be activated by natural response to cell stress
Scientists from the Florida campus of The Scripps Research Institute (TSRI) have found that a drug candidate with anticancer potential can be activated by one of the body's natural responses to cellular stress.
Study: Top salads with eggs to better absorb vegetables' carotenoids
Adding eggs to a salad with a variety of raw vegetables is an effective method to improve the absorption of carotenoids, which are fat-soluble nutrients that help reduce inflammation and oxidative stress, according to research from Purdue University.
Mediterranean diet plus olive oil or nuts associated with improved cognitive function
Supplementing the plant-based Mediterranean diet with antioxidant-rich extra virgin olive oil or mixed nuts was associated with improved cognitive function in a study of older adults in Spain but the authors warn more investigation is needed, according to an article published online by JAMA Internal Medicine.
How oxidizing a heart 'brake' causes heart damage
Oxidative stress has been long known to fuel disease, but how exactly it damages various organs has been challenging to sort out.
Virginia Tech researcher shines light on origin of bioluminescence
In the mountains of Virginia, millipedes have bright yellow and black colors to warn enemies that they are toxic and not worth eating. Their cousins in California convey this warning in a very different way -- by glowing in the dark.
Moffitt researchers discover new mechanism controlling cell response to DNA damage
DNA can be damaged by different environmental insults, such as ultraviolet light, ionizing radiation, oxidative stress or certain drugs.
More Oxidative Stress Current Events and Oxidative Stress News Articles