Antichagasic effect of crotalicidin, a cathelicidin-like vipericidin, found in Crotalus durissus terrificus rattlesnake's venom gland.

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.

The dinoponeratoxin peptides from the giant ant Dinoponera quadriceps display in vitro antitrypanosomal activity.

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.

Evaluation of the antichagasic activity of batroxicidin, a cathelicidin-related antimicrobial peptide found in Bothrops atrox venom gland.

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.

Clinical events and their relation to the tumor necrosis factor-alpha and interleukin-10 genotypes in Sickle-Cell-Anemia patients.

OBJECTIVE/BACKGROUND: Sickle-cell anemia (SCA) is a genetic blood disease characterized by chronic inflammation and a heterogeneous clinical picture. Serum tumor necrosis factor (TNF-alpha) and interleukin 10 (IL-10) levels are associated with the clinical course of SCA. This study aimed to evaluate the association between the frequency of the polymorphisms TNF-alpha-308 G→A, IL-10-1082 G→A, IL-10-819 C→T, and IL-10-592 A→C; serum TNF-alpha; and IL-10 levels, and the incidence of clinical events in SCA patients. METHODS: Polymerase chain reaction-restriction fragment length polymorphism and enzyme-linked immunosorbent assay were performed on 25 adults with SCA at the steady state; their data were compared with those for 26 healthy individuals. RESULTS: The most frequent genotype of the TNF-alpha polymorphism was GG (low producer), and the most frequent genotype of the IL-10 polymorphisms was "low producer" (ACC ACC, ACC ATA, ATA ATA). The TNF-alpha levels were significantly higher in SCA in patients with acute chest syndrome (ACS). The IL-10 levels were reduced in polytransfusion and in patients with ACS. CONCLUSION: The patients presented prevalence of TNF-alpha and IL-10 low-profile producer. The cytokine serum levels presented an association with the presence of polytransfusion and ACS in SCA patients.

Estudo dos marcadores de inflamação: associação com os haplótipos do cluster da B-globina na anemia falciforme

A Anemia Falciforme (AF) é uma doença hereditária homozigótica caracterizada por anemia hemolítica grave e manifestações clínicas variáveis, considerada uma doença inflamatória crônica. A AF resulta de uma mutação pontual em uma base nitrogenada no sexto códon do gene da beta globina, levando a substituição do nucleotídeo adenina por timina (GAG →GTG), o que resulta na produção do aminoácido valina no lugar do ácido glutâmico. A fisiopatologia inflamatória da AF está centralizada na capacidade de polimerização da HbS que leva à hemólise crônica e à vaso-oclusão. Os pacientescom AF encontram-se em um estado inflamatório crônico de origem multifatorial, que envolve células endoteliais, eritrócitos, leucócitos e plaquetas através do aumento nas interações entre célula-célula e célula-endotélio iniciando uma lesão endotelial. O estudo foi do tipo transversal prospectivo com a finalidade de investigar a associação dos haplótipos com o perfil inflamatório de pacientes com AF. Foi realizada a confirmação da HbSS e em seguida o estudo dos haplótipos da mutação BS no gene da cadeia beta globínica. Foram dosados os marcadores IL-6, IL-8, TNF-α, IL-17, PCR-us, IL-10 e TGF-βem 67 pacientes com AF e em 26 indivíduos saudáveis. Observou-se a prevalência do haplótipo Bantu (67,1%) na população de pacientes estudada, seguido do haplótipo Benin (28,3%). O estudo confirma que os pacientes com AF encontram-se em um estado inflamatório crônico, pois apresentaram valores elevados de marcadores pró-inflamatórios e antiinflamatório, quando comparadas à indivíduos saudáveis. O haplótipo Bantu obteve mais elevados índices das citocinas pró-inflamatórias e da PCR-us quando comparados aos valores para o Haplótipo Benin...

The Sickle Cell Anemia (SCA) is an inherited disease characterized by homozygous severe hemolytic anemia and clinical variables, considered a chronic inflammatory disease. SCA results from a mutation in a nitrogenous base in the sixth codon of the beta globin gene, leading to substitution of adenine for thymine nucleotide (GAG →GTG), which results in the production of the amino acid valine in place of glutamic acid. The inflammatory pathophysiology of SCA is centered on the ability of HbS polymerization that leads to chronic hemolysis and vaso-occlusion. SCA patients are a chronic inflammatory state of multifactorial origin that involves endothelial cells, erythrocytes, leukocytes and platelets by increasing the interactions between cell-cell and cell-endothelium starting an endothelial injury. The study was a cross-sectional prospective in order to investigate the association of haplotypes with the inflammatory profile of patients with AF. Was performed to confirm the HbSS and then study the haplotypes BS mutation in the gene for beta globin chain. We measured markers IL-6, IL-8, TNF-α, IL-17, CRP, IL-10 and TGF-β on 67 patients with SCA and 26 healthy subjects. We observed the prevalence of Bantu haplotype (67.1%) in the patient population studied, followed by the Benin haplotype (28.3%). The study confirms that SCA patients are in a chronic inflammatory state, as had elevated markers of proinflammatory and anti-inflammatory when compared to healthy subjects. The Bantu achieved higher levels of proinflammatory cytokines and CRP compared to the values for Haplotype Benin...

Influence of ßS-globin haplotypes and hydroxyurea on tumor necrosis factor-alpha levels in sickle cell anemia.

BACKGROUND: Sickle 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. OBJECTIVE: The aim of this study was to investigate the association of tumor necrosis factor-alpha levels with ß-globin haplotypes and the use of hydroxyurea. METHODS: A 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. ßS-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. RESULTS: The 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). CONCLUSION: In summary, ßS-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.

Influence of ?S-globin haplotypes and hydroxyurea on tumor necrosis factor-alpha levels in sickle cell anemia

Background: Sickle 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. Objective: The aim of this study was to investigate the association of tumor necrosis factor-alpha levels with β-globin haplotypes and the use of hydroxyurea. Methods: A 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. Results: The 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). Conclusion: In 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...

DNA damage in leukocytes of sickle cell anemia patients is associated with hydroxyurea therapy and with HBB*S haplotype.

Hydroxyurea (HU) is the primary pharmacologic agent for preventing the complications and improving the quality of life of sickle cell anemia (SCA) patients. Although HU has been associated with an increased risk of leukemia in some patients with myeloproliferative disorders, the mutagenic and carcinogenic potential of HU has not been established. This study used the alkaline comet assay to investigate DNA damage in peripheral blood leukocytes from 41 individuals with SCA treated with HU (SCAHU) and from 26 normal individuals. The presence of HbS and the analysis of the haplotypes of the beta S gene cluster were done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The damage index (DI) in the SCAHU group was significantly higher than in controls (p<0.001). Neither gender nor age was associated with DNA damage in controls or SCAHU individuals. Among the SCAHU individuals, DI was significantly influenced by length of HU treatment (p=0.0039) and BMI (p=0.001). Individuals with length of HU treatment≥20 months and BMI≤20kg/m(2) had a significantly greater DI than those with length of HU treatment<20 months and BMI>20kg/m(2). No significant influence of mean HU dose was observed on DI (p=0.950). However, individuals who received a mean HU dose≥20mg/kg showed a higher DI than those who received less. Furthermore, an association was observed between DI damage and HBB*S gene haplotypes. DI values for the Bantu/Bantu haplotype was greater when compared to the Benin/Benin haplotype; and the Bantu/Benin haplotype had a DI lower than the Bantu/Bantu haplotype and greater than the Benin/Benin haplotype. Our results show that DNA damage in sickle cell anemia is associated not only with treatment with HU but also with genotype.