People suffering from cystic fibrosis have less ability to uptake and use oxygen in their muscles, which leads to exercise intolerance, a study published in Experimental Physiology concluded.
Cystic fibrosis (CF) is a genetic disease affecting multiple organs, in which, primarily the lungs and digestive system, become obstructed by mucus, causing difficulties in breathing and digesting food. Researchers have now found that people suffering from CF have limited ability to uptake and use oxygen in their muscles, which gets worse with age. A lack of oxygen leads to a limited ability to exercise, which is an important tool to achieve a better and prolonged life quality in these patients.
In their study, the team of researchers used Near Infrared Spectroscopy (NIRS) as a new method to evaluate skeletal muscle oxidative capacity in patients with CF. They compared skeletal muscle oxidative capacity in a group of 13 patients with CF (aged 7-42 years) and a group of healthy controls (no=16, aged 7-59 years). The NIRS device was placed on the middle of the thigh and a blood pressure-like cuff was placed on the upper thigh. The pressure cuff was inflated on the thigh to measure muscle tissue oxygen response over time.
Dr Ryan Harris, Director of the Laboratory of Integrative Vascular and Exercise Physiology in the Medical College of Georgia at Georgia Regents University and senior author of this study says, 'This study is extremely relevant to people affected by CF. The ability to measure the capacity of muscles to use oxygen non-invasively using NIRS is a big plus. Using this methodology is a lot cheaper compared to other imaging modalities like magnetic resonance imaging, and it can be repeated as often as needed throughout a study, without any radiation exposure. Last, but certainly not least, we can use the NIRS technique in children, which gives it a huge advantage over invasive procedures such as muscle biopsies.'
Prof Kevin K. McCully from the University of Georgia and investigator of the study commented, 'Exercise is not only important to improve life quality in patients with CF, it is also an effective tool to measure the progression of the disease. In addition to other symptoms, excessive muscle weakness is very common in people with CF. It has been assumed that this weakness isn't due to a lack of physical activity, and our study confirms that reduced oxidative capacity caused by defects in the mitochondria (structures in the cell that are responsible for generating energy) plays an important role.'
Dr Ryan Harris adds, 'The use of the NIRS technique to evaluate skeletal muscle oxidative capacity in humans has just begun and this is the first study to evaluate patients with CF. We have identified an impairment in patients and the next step would be to try to develop treatments or therapies that can improve muscle function in this patient population.'