Hellebrigenin triggers death of promyelocytic leukemia cells by non-genotoxic ways.

Bufadienolides are digitalis-like aglycones mainly found in skin secretions of toads. Among their biological properties, the mechanisms of antiproliferative action on tumor cells remain unclear for many compounds, including against leukemia cells. Herein, it was evaluated the mechanisms involved in the antiproliferative and genotoxic actions of hellebrigenin on tumor cell lines and in silico capacity to inhibit the human topoisomerase IIa enzyme. Firstly, its cytotoxic action was investigated by colorimetric assays in human tumor and peripheral blood mononuclear cells (PBMC). Next, biochemical and morphological studies were detailed by light microscopy (trypan blue dye exclusion), immunocytochemistry (BrdU uptake), flow cytometry and DNA/chromosomal damages (Cometa and aberrations). Finally, computational modelling was used to search for topoisomerase inhibition. Hellebrigenin reduced proliferation, BrdU incorporation, viability, and membrane integrity of HL-60 leukemia cells. Additionally, it increased G2/M arrest, internucleosomal DNA fragmentation, mitochondrial depolarization, and phosphatidylserine externalization in a concentration-dependent manner. In contrast to doxorubicin, hellebrigenin did not cause DNA strand breaks in HL-60 cell line and lymphocytes, and it interacts with ATPase domain residues of human topoisomerase IIa, generating a complex of hydrophobic and van der Waals interactions and hydrogen bonds. So, hellebrigenin presented potent anti-leukemic activity at concentrations as low as 0.06 µM, a value comparable to the clinical anticancer agent doxorubicin, and caused biochemical changes suggestive of apoptosis without genotoxic/clastogenic-related action, but it probably triggers catalytic inhibition of topoisomerase II. These findings also emphasize toad steroid toxins as promising lead antineoplasic compounds with relatively low cytotoxic action on human normal cells.

C-reactive protein for the diagnosis and prognosis of visceral leishmaniasis caused by Leishmania infantum

Acute-phase reaction (APR) and its marker C-reactive protein (CRP) are heightened in some infectious diseases. APR may contribute to clinical manifestations of systemic inflammation such as hemorrhages, anemia and edema. These symptoms are shared by visceral leishmaniasis (VL), a disease caused by the protozoa Leishmania infantum and L. donovani. The former is zoonotic, hitting mostly children and the immunosuppressed, with higher mortality. As APR and CRP have not been studied in VL caused by L. infantum, we decided to investigate their role as diagnostic and prognostic tools in Brazil. We measured CRP in 136 patients before the treatment of VL and 128 who survived and returned 30 days later and compared it to the clinical presentation, HIV status, and disease severity. Sensitivity for the disease was 97.8% (95%CI: 93.7 - 99.5) and specificity was 85.9% (95%CI: 78.7 - 91.0) with the cut-off of 10mg/L. There was no association of CRP concentration with demographic, clinical and laboratory data. The correlation between pre-and post-treatment levels existed but was poor. Marginal association with the presence of parasites in the bone marrow and death was noticed. The role of APR in the pathogenesis of VL and disease severity remains to be explored. However, the study reveals the significant role of CRP for VL caused by L. infantum and should be routinely required for the diagnosis and follow-up.

Nutritional status and vitamin A and zinc levels in patients with kala-azar in Piauí, Brazil

Abstract INTRODUCTION: Malnutrition and kala-azar (or visceral leishmaniasis) are significant public health problems in different parts of the world. Immunity and susceptibility to infectious and parasitic diseases are directly linked to the host's nutritional state, but little is known about the interaction between nutrition and kala-azar. This study aimed to evaluate nutritional status with kala-azar and correlate these findings with the clinical and laboratory manifestations of the disease, and zinc and retinol levels. METHODS: This was a cross-sectional study of 139 patients with kala-azar. Nutritional status classification was performed according to international recommendations. Parametric or nonparametric tests were applied whenever indicated in a two-sided test with a 5% significance level. RESULTS: Weight loss and malnutrition were more frequent in adults. Body mass index-for-age, fat area of the arm, and upper arm muscle area were significantly associated with probability of death. The presence of human immunodeficiency virus, hepatomegaly, and splenomegaly was correlated with nutritional assessment. Blood leukocyte and lymphocyte, serum creatine, and vitamin A levels were significantly higher in adult men. Vitamin A levels were highly associated with the level of hemoglobin and C-reactive protein (CRP) in multivariate analysis. All patients had reduced plasma zinc levels, but this finding had no association with the outcome variables. CONCLUSIONS: Malnutrition was correlated with severe disease and was more prevalent in older people with kala-azar. Vitamin A deficiency was associated with hemoglobin and CRP. Zinc levels were reduced in patients with kala-azar.