Determinação de oligoelementos e elementos potencialmente tóxicos no sangue de pacientes com leucemia linfocítica aguda

Abstract

Acute lymphocytic leukemia (ALL) is a type of cancer that affects the bone marrow, changing the hematopoietic process due to a genetic mutation that affects the stem cells of lymphoid origin. So, immature lymphoblasts are generated, which have no blood function and accumulate in the bone marrow. This type of cancer occurs mainly in children, who represent the majority of cases of this disease. Currently, chemotherapy is the most used treatment for the remission of the disease since it generates a survival of approximately 80%. However, treatment can end up destroying normal and healthy cells, such as enzymes and important proteins in the body, which usually have or require trace elements to properly perform their functions. Therefore, this study aimed to investigate the variation of trace elements in the blood of patients with ALL to verify how chemotherapy can affect the availability of some essential elements. Furthermore, there are also potentially toxic elements that have already been related to the occurrence of various types of cancers. Knowing this, we also sought to determine elements harmful to health in order to investigate possible relationships between them and the occurrence of ALL. For this purpose, sample preparation tests were performed with solubilization in alkaline medium, by using tetramethylammonium hydroxide (TMAH) and decomposition in an acid medium. Element concentration was performed by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled atomic emission spectrometry (ICP OES) techniques. By means of statistic tests, it was possible to verify that no significant differences in the mean concentration of trace elements were observed in patients submitted to chemotherapy, except for iron (Fe), which increased. The increase of Fe concentration may be associated with blood transfusions that patients were submitted and that can cause Fe overload in the body. It seems that blood transfusions, factors such as feeding and environmental characteristic of the region where the patient resides and LLA have no influences on the trace elements investigated, since no significant differences throughout treatment against ALL were observed. Similarly, the non-essential elements determined also had no significant differences, indicating that patients were not exposed to high levels of these elements during the study period. Consequently, no evidence was observed that correlates ALL with these harmful elements. In relation of sample preparation, treatment with TMAH allows a faster method and requires low volumes of reagent and simple equipment. However, it was not efficient for the solubilization of blood samples since the final solution was cloudy, with presence of solid material, making analysis by ICP-MS or ICP OES impossible. Therefore, acid decomposition was used for sample preparation, where quantitative analyte recovery was achieved through addition and recovery tests.