Biomarkers of fatigue induced by chemotherapy for breast cancer during guarana (Paullinia cupana) treatment

Abstract

As the result of the advances in cancer treatment, the number of cancer survivors has increased. One of the most experienced side effects by them is fatigue, a chronic sensation of tiredness, exhaustion and lack of metal e phisical energy. In some patients fatigue can persist despite of the correction of related problems (depression, amnemia, hypothyroidism, and sleep disturbances). Patients with persistant fatigue show alterations in the levels of cytokines and inflamatory markers, in the hypothalamic-pituitary-adrenal axis (HPA), and high oxidants concentrations. Our group conducted a clinical trial with breast cancer patients undergoing chemotherapy and suffering of fatigue, in which the benefits of guaraná extract (Paullinia cupana) were demonstrated. Guaraná is known to be an antioxidant but its effects on inflamation and on the HPA axis are not clear. So, the analysis of these patients may help us understand the effects of guaraná and the mechanisms related to fatigue. In addition, the fatigue induced by chemotherapy can be considered as a in vivo human model of the onset of fatigue. Since there is no standard exam for fatigue, the study of proteins and the gene expression of peripheral blood of fatigue patients can provide useful markers. As a treatment capable of attenuating fatigue simptoms is available, the study of the behavior of such proteins and genes during guaraná treatment can not only to determine its utility as fatigue markers but also help the comprehension of the mechanisms underlying this disease. Therefore, the goal of this study is to determine biomarkers of chemotherapy related-fatigue and to assess this marker during guaraná treatment. (AU)