Content of Monoamines in Blood and Tumor Tissue in Patients with Bladder Cancer Depending on the Presence of Diabetes Mellitus

INTRODUCTION: According to the literature, the risk of developing bladder cancer (BC) which is included in the top ten most common cancers in the world and characterized by a tendency to recurrence and metastasizing may be associated with the existence of diabetes mellitus (DM) in patients. Monoamines are known to be involved in the proliferation and dissemination processes, and can affect the immune and endothelial cells in the tumor micro-environment contributing to the progression of tumor growth. Impaired serotonin metabolism is considered an unfavorable factor of the development of diabetic pathology, which underlies the interest in investigation of the influence of diabetes mellitus on the content and metabolism of monoamines in patients with BC. AIM: To assess the content of biogenic monoamines in blood and tumor tissue in BC patients with and without DM. MATERIALS AND METHODS: The work includes data from 22 patients with non-muscle invasive BC, divided into two groups of 11 patients each depending on the presence of type 2 diabetes (DM2), and also two comparison groups: 11 persons without oncological diseases and DM (donors) and 8 persons without oncological diseases with DM2. The content of dopamine (DA), norepinephrine (NA), serotonin (SR) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) obtained in transurethral resection in patients with bladder cancer, was determined in blood plasma and in 10% tumor tissue homogenates using enzyme immunoassay. RESULTS: Patients with BC with and without DM, were characterized by more than three times decrease in the blood level of NA relative to the donor group, without statistically significant changes in the contents of DA and SR, as well as by three to four times decrease in the ratio of NA to DA and SR in most patients. Tumor tissue in patients with DM was characterized by a lower content of NA and 5-HIAA and also by two and a half times decrease in 5-HIAA to SR ratio. At the same time, in patients with DM2 (without cancer), an almost two times increase in 5-HIAA/SR index in the blood and urine was observed, indicating a possible role of monoamine oxidase (MAO) activation, contributing to the development of MAO-dependent oxidative stress in diabetes. CONCLUSION: The obtained data suggest the participation of monoamines, changes in their proportion and metabolism in realization of the influence of DM on the course of malignant disease.