Platinum and Palladium Organometallic Compounds: Disrupting the Ergosterol Pathway in Trypanosoma cruzi.

Current treatment for Chagas' disease is based on two drugs, Nifurtimox and Benznidazol, which have limitations that reduce the effectiveness and continuity of treatment. Thus, there is an urgent need to develop new, safe and effective drugs. In previous work, two new metal-based compounds with trypanocidal activity, Pd-dppf-mpo and Pt-dppf-mpo, were fully characterized. To unravel the mechanism of action of these two analogous metal-based drugs, high-throughput omics studies were performed. A multimodal mechanism of action was postulated with several candidates as molecular targets. In this work, we validated the ergosterol biosynthesis pathway as a target for these compounds through the determination of sterol levels by HPLC in treated parasites. To understand the molecular level at which these compounds participate, two enzymes that met eligibility criteria at different levels were selected for further studies: phosphomevalonate kinase (PMK) and lanosterol 14-α demethylase (CYP51). Molecular docking processes were carried out to search for potential sites of interaction for both enzymes. To validate these candidates, a gain-of-function strategy was used through the generation of overexpressing PMK and CYP51 parasites. Results here presented confirm that the mechanism of action of Pd-dppf-mpo and Pt-dppf-mpo compounds involves the inhibition of both enzymes.

Preclinical Studies and Drug Combination of Low-Cost Molecules for Chagas Disease.

Chagas disease is caused by the protozoan Trypanosoma cruzi (T. cruzi). It remains the major parasitic disease in Latin America and is spreading worldwide, affecting over 10 million people. Hundreds of new compounds with trypanosomicidal action have been identified from different sources such as synthetic or natural molecules, but they have been deficient in several stages of drug development (toxicology, scaling-up, and pharmacokinetics). Previously, we described a series of compounds with simple structures, low cost, and environmentally friendly production with potent trypanosomicidal activity in vitro and in vivo. These molecules are from three different families: thiazolidenehydrazines, diarylideneketones, and steroids. From this collection, we explored their capacity to inhibit the triosephosphate isomerase and cruzipain of T. cruzi. Then, the mechanism of action was explored using NMR metabolomics and computational molecular dynamics. Moreover, the mechanism of death was studied by flow cytometry. Consequently, five compounds, 314, 793, 1018, 1019, and 1260, were pre-clinically studied and their pharmacologic profiles indicated low unspecific toxicity. Interestingly, synergetic effects of diarylideneketones 793 plus 1018 and 793 plus 1019 were evidenced in vitro and in vivo. In vivo, the combination of compounds 793 plus 1018 induced a reduction of more than 90% of the peak of parasitemia in the acute murine model of Chagas disease.

Hematological and biochemical profiles of canine CD45- T lymphomas are different from other immunophenotypes.

BACKGROUND: Canine multicentric lymphomas are lymphoproliferative malignancies that have increased in recent decades. The patient's treatment and prognosis are determined by the grade, histological type, and lymphoma immunophenotyping. AIM: To investigate the paraclinical signs and survival time in canines with different lymphoma immunophenotypes. METHODS: Over 2 and a half years, 47 untreated dogs were diagnosed with multicentric lymphoma at the Veterinary School Hospital of Uruguay. The disease was clinically and cytologically diagnosed, and immunophenotyping was determined by flow cytometry. After the immunophenotyping, most of the patients were grouped into the following: B (LB), T aggressive (LTCD45+), or T-zone lymphoma (LTCD45-). The patients' haematological values, calcemia, lactate dehydrogenase (LDH) levels, and plasmatic electrophoretic profiles were all determined immediately after that. RESULTS: Of all canine lymphomas, 55.3% were B, 31.9% were LTCD45+, and 10.6% were TCD45-. Only 2.2% were classified as nonB/nonT, and survival time differed between groups. Patients with LTCD45- lymphomas had a mean life span of 641 days after diagnosis, followed by LB (166 days) and LTCD45+ (62 days). Red blood cell count, hematocrit, and hemoglobin levels did not differ between groups. However, the LTCD45- group had significantly higher lymphocyte levels than the LTCD45+ and LB groups (p = 0.01 and 0.006, respectively). Levels of albumin, alpha-1, and alpha-2 globulins did not differ between groups. On the other hand, gamma globulins levels in the LTCD45- were higher than in the other lymphoma groups. The presence of hypercalcemia and high plasma LDH levels were associated with patient severity. Only the TCD45+ group had hypercalcemia although both the LB and TCD45+ groups had elevations in LDH activity. Interestingly, there was a direct relationship between high LDH values (greater than 500 IU/l) and lower survival in TCD45+ lymphomas. CONCLUSION: Survival time and hematological and biochemical patterns differed among canine lymphomas immunophenotypes. Patients of LTCD45- phenotype showed higher lymphocyte counts and gamma globulin levels and more prolonged survival. Serum LDH activity may provide additional prognostic information in high-grade T-cell lymphoma.