The chronic inflammatory state in sickle cell anemia (SCA) is associated with several factors such as the following: endothelial damage; increased production of reactive oxygen species; hemolysis; increased expression of adhesion molecules by leukocytes, erythrocytes, and platelets; and increased production of proinflammatory cytokines. Genetic characteristics affecting the clinical severity of SCA include variations in the hemoglobin F (HbF) level, coexistence of alpha-thalassemia, and the haplotype associated with the HbS gene. The different haplotypes of SCA are Bantu, Benin, Senegal, Cameroon, and Arab-Indian. These haplotypes are associated with ethnic groups and also based on the geographical origin. Studies have shown that the Bantu haplotype is associated with higher incidence of clinical complications than the other haplotypes and is therefore considered to have the worst prognosis. This study aimed to evaluate the profile of the proinflammatory cytokines interleukin-6, tumor necrosis factor-α, and interleukin-17 in patients with SCA and also to assess the haplotypes associated with beta globin cluster S (HBB(*)S). We analyzed a total of 62 patients who had SCA and had been treated with hydroxyurea; they had received a dose ranging between 15 and 25 (20.0±0.6)mg/kg/day for 6-60 (18±3.4)months; their data were compared with those for 30 normal individuals. The presence of HbS was detected and the haplotypes of the beta S gene cluster were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Our study demonstrated that SCA patients have increased inflammatory profile when compared to the healthy individuals. Further, analysis of the association between the haplotypes and inflammatory profile showed that the levels of IL-6 and TNF-α were greater in subjects with the Bantu/Bantu haplotype than in subjects with the Benin/Benin haplotype. The Bantu/Benin haplotype individuals had lower levels of cytokines than those with the Bantu/Bantu haplotype and greater levels than those of subjects with the Benin/Benin haplotype. For IL-17, a slight trend toward decreased levels was observed in the subjects with the Benin/Benin haplotype, when compared to those with the Bantu/Bantu and Bantu/Benin haplotypes; however, this difference was not statistically significant. Our results show that genetic polymorphisms in sickle cell anemia are associated with the inflammatory profile.

Cathelicidins are antimicrobial peptides produced by humans and animals in response to various pathogenic microbes. Crotalicidin (Ctn), a cathelicidin-related vipericidin from the South American Crotalus durissus terrificus rattlesnake's venom gland, and its fragments have demonstrated antimicrobial and antifungal activity, similarly to human cathelicidin LL-37. In order to provide templates for the development of modern trypanocidal agents, the present study evaluated the antichagasic effect of these four peptides (Ctn, Ctn[1-14], Ctn[15-34] and LL-37). Herein, Ctn and short derived peptides were tested against the epimastigote, trypomastigote and amastigote forms of Trypanosoma cruzi Y strain (benznidazole-resistant strain) and cytotoxicity in mammalian cells was evaluated against LLC-MK2 lineage cells. Ctn inhibited all T. cruzi developmental forms, including amastigotes, which is implicated in the burden of infection in the chronic phase of Chagas disease. Moreover, Ctn showed a high selective index against trypomastigote forms (>200). Ctn induced cell death in T. cruzi through necrosis, as determined by flow cytometry analyses with specific molecular probes and morphological alterations, such as loss of membrane integrity and cell shrinkage, as observed through scanning electron microscopy. Overall, Ctn seems to be a promising template for the development of antichagasic agents.

Antimicrobial peptides (AMPs) are potential alternatives to conventional antibiotics, as they have a fast mode of action, a low likelihood of resistance development and can act in conjunction with existing drug regimens. We report in this study the effects of batroxicidin (BatxC), a cathelicidin-related AMP from Bothrops atrox venom gland, over Trypanosoma cruzi, a protozoan that causes Chagas' disease. BatxC inhibited all T. cruzi (Y strain: benznidazole-resistant) developmental forms, with selectivity index of 315. Later, separate flow cytometry assays showed T. cruzi cell labeling by 7-aminoactinomycin D, the increase in reactive oxygen species and the loss of mitochondrial membrane potential when the parasite was treated with BatxC, which are indication of necrosis. T. cruzi cell death pathway by a necrotic mechanism was finally confirmed by scanning electron microscopy which observed loss of cell membrane integrity. In conclusion, BatxC was able to inhibit T. cruzi, with high selectivity index, by inducing necrosis.

The crude venom of the giant ant Dinoponera quadriceps is a cocktail of polypeptides and organic compounds that shows antiparasitic effects against Trypanosoma cruzi, the causative agent of Chagas disease. In order to investigate the venom-derived components responsible for such antitrypanosomal activity, four dinoponeratoxins (DnTxs) were identified, namely M-PONTX-Dq3a, -Dq3b, -Dq3c and -Dq4e, that are diverse in size, net charge, hydrophobicity and propensity to interact with eukaryote cell membranes. These peptides were tested against epimastigote, trypomastigote and amastigote forms of benznidazole (Bz)-resistant Y strain of T. cruzi and in mammalian host cells. The M-PONTX-Dq3a and -Dq4e inhibited all developmental forms of T. cruzi, including amastigotes, the responsible form for the maintenance of infection on chronic phase of the disease. The M-PONTX-Dq3a showed the highest selectivity index (SI) (80) and caused morphological alterations in T. cruzi, as observed by scanning electron microscopy (SEM), and induced cell death through necrosis, as seen by multiparametric flow cytometry analysis with specific biochemical markers. Altogether, the D. quadriceps venom appears as a source for the prospection of trypanocidal peptides and the M-PONTX-Dq3a arises as a candidate among the dinoponeratoxin-related peptides in the development of compounds against Chagas disease.

BackgroundSickle cell anemia is a chronic inflammatory disease characterized by an increased production of proinflammatory cytokines including tumor necrosis factor-alpha. Hydroxyurea, by decreasing the polymerization of hemoglobin, reduces inflammatory states. The effect of the genetic polymorphisms of sickle cell patients on tumor necrosis factor-alpha levels remains unknown.ObjectiveThe aim of this study was to investigate the association of tumor necrosis factor-alpha levels with β-globin haplotypes and the use of hydroxyurea.MethodsA cross-sectional study was performed of 67 patients with sickle cell anemia diagnosed at steady-state in a referral hospital in Fortaleza, Ceará, Brazil. A group of 26 healthy individuals was used as control. βS haplotype analysis was performed by restriction fragment length polymorphism-polymerase chain reaction. The tumor necrosis factor- alpha levels were measured by the enzyme-linked immunosorbent assay test. Laboratory data (complete blood count and fetal hemoglobin) and information regarding the use of hydroxyurea were obtained from medical records. Statistical analysis was performed using R software with the Kruskal-Wallis and Mann–Whitney tests. Statistical significance was established for p-values < 0.05 for all analyses.ResultsThe mean age of the participants was 35.48 years. Patients with sickle cell anemia had significantly higher tumor necrosis factor-alpha levels than controls (p-values < 0.0001). Tumor necrosis factor-alpha levels were lower in sickle cell anemia patients who were receiving hydroxyurea treatment than those who were not (p-value = 0.1249). Sickle cell anemia patients with Bantu/n genotype had significantly higher levels than patients with the Bantu/Benin genotype (p-value = 0.0021).ConclusionIn summary, βS-globin haplotypes, but not hydroxyurea therapy, have a role in modulating tumor necrosis factor-alpha levels in sickle cell anemia adults at steady-state. Many previous studies have investigated prognosis and inflammatory states in sickle cell anemia patients, but the discovery that tumor necrosis factor-alpha levels vary according to the genetic polymorphism of the patient is a new finding. © 2014 Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular. All rights reserved.