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The compositional landscape of minicircle sequences isolated from active lesions and scars of American cutaneous leishmaniasis.

ABSTRACT: BACKGROUND: American cutaneous leishmaniasis (ACL) is characterized by cutaneous lesions that heal spontaneously or after specific treatment. This paper reports on the analysis of kDNA minicircle sequences from clinical samples (typical lesions and scars) that were PCR-amplified with specific primers for Leishmania species of the subgenus Viannia. METHODS: From 56 clinical isolates we obtained a single amplified fragment (ca. 790 bp), which after cloning and sequencing resulted in 290 minicircle sequences from both active lesions and scars. We aimed to get a compositional profile of these sequences in clinical samples and evaluate the corresponding compositional changes. Sequences were analyzed with the compseq and wordcount (Emboss package) to get the composition of di-, tri-, tetra-, penta- and hexanucleotides. Additionally, we built a nucleotide dictionary with words of 7, 8, 9 and 10 nucleotides. RESULTS: This compositional analysis showed that minicircles amplified from active cutaneous lesions and scars have a distinct compositional profile as viewed by nucleotide composition of words up to 10mer. With regard to the most frequent nucleotide words above length 6, there is also a distinct pattern for 7, 8, 9 and 10mer. CONCLUSION: These results indicate that minicircle sequences can be monitored upon direct exposure to a selection/stressing environment (e.g. chemical action) by evaluating their nucleotide compositional profile. It might be useful as a molecular tool in research concerning the evolution of infecting Leishmania in both vector and vertebrate hosts.

SUBMITTER: Rodrigues EH

PROVIDER: S-EPMC3750493 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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The compositional landscape of minicircle sequences isolated from active lesions and scars of American cutaneous leishmaniasis.

Rodrigues Eduardo Henrique Gomes EH Soares Fábia Carla da Silva FC Werkhäuser Roberto Pereira RP de Brito Maria Edileuza F ME Fernandes Octavio O Abath Frederico G Coutinho FG Brandão Adeilton A

Parasites & vectors 20130807

<h4>Background</h4>American cutaneous leishmaniasis (ACL) is characterized by cutaneous lesions that heal spontaneously or after specific treatment. This paper reports on the analysis of kDNA minicircle sequences from clinical samples (typical lesions and scars) that were PCR-amplified with specific primers for Leishmania species of the subgenus Viannia.<h4>Methods</h4>From 56 clinical isolates we obtained a single amplified fragment (ca. 790 bp), which after cloning and sequencing resulted in 2 ...[more]

PMID: 23924509

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Project description:We evaluated the importance of neutrophils in the development of chronic lesions caused by L. Viannia spp. using the hamster as experimental model of American Cutaneous Leishmaniasis (ACL). Neutrophils infiltrated the lesion within the first six hours post-infection. Inhibition of this early infiltration using a polyclonal antibody or cyclophosphamide was associated with transient parasite control but the protective effect vanished when lesions became clinically apparent. At lesion onset (approximately 10 days p.i.), there was an increased proportion of both uninfected and infected macrophages, and subsequently a second wave of neutrophils infiltrated the lesion (after 19 days p.i.) This second neutrophil infiltration was associated with lesion necrosis and ulceration (R2 = 0.75) and maximum parasite burden. Intradermal delivery of N-formylmethionyl-leucyl-phenylalanine (fMLP), aimed to increase neutrophil infiltration, resulted in larger lesions with marked necrosis and higher parasite burden than in mock treated groups (p<0.001 each). In contrast, reduced neutrophil infiltration via cyclophosphamide-mediated depletion led to more benign lesions and lower parasite loads compared to controls (p<0.001 each). Neutrophils of the second wave expressed significantly lower GM-CSF, reactive oxygen species and nitric oxide than those of the first wave, suggesting that they had less efficient anti-leishmania activity. However, there was increased inflammatory cytokines and expression of neutrophil proteases (myeloperoxidase, cathepsin G and elastase) in lesions during the second wave of neutrophil infiltration compared with the levels reached during the first wave (6h p.i.). This suggests that augmented neutrophil proteases and inflammatory cytokines during the secondary wave of neutrophils could contribute to skin inflammation, ulceration and necrosis in ACL. The overall results indicate that neutrophils were unable to clear the infection in this model, and that the second wave of neutrophils played an important role in the severity of ACL.

Project description:Neutrophil extracellular traps (NETs) have been described as a network of extracellular fibers composed by DNA, histones and various proteins/enzymes. Studies have demonstrated that NETs could be responsible for the trapping and elimination of a variety of infectious agents. In order to verify the presence of NETs in American tegumentary leishmaniasis (ATL) and their relationship with the presence of amastigotes we evaluated active cutaneous lesions of 35 patients before treatment by the detection of parasites, neutrophils (neutrophil elastase) and histones through immunohistochemistry and confocal immunofluorescence. Intact neutrophils could be detected in all ATL lesions. NETs were present in 27 patients (median 1.1; range from 0.1 to 23.5/mm2) with lesion duration ranging from one to seven months. NETs were in close proximity with neutrophils (r = 0.586; p = 0.0001) and amastigotes (r = 0.710; p = 0.0001). Two patterns of NET formation were detected: small homogeneously distributed networks observed in all lesions; and large structures that could be visualized at a lower magnification in lesions presenting at least 20% of neutrophils. Lesions presenting the larger NET formation showed high parasite detection. A correlation between NET size and the number of intact amastigotes was observed (p=0.02). As we detected an association between NET and amastigotes, our results suggest that neutrophil migration and NET formation could be stimulated and maintained by stimuli derived from the parasite burden/parasite antigen in the extracellular environment. The observation of areas containing only antigens not intermingled with NETs (elastase and histone) suggests that the involvement of these structures in the control of parasite burden is a dynamic process in which the formation of NETs is exhausted with the destruction of the parasites. Since NETs were also associated with granulomas, this trapping would favor the activity of macrophages in order to control the parasite burden.

Project description:Pentavalent antimonials (Sb5) and miltefosine are the first-line drugs for treating cutaneous leishmaniasis in Colombia; however, toxicity and treatment duration negatively impact compliance and cost, justifying an active search for better therapeutic options. We compared the efficacy and safety of thermotherapy and meglumine antimoniate for the treatment of cutaneous leishmaniasis in Colombia.An open randomized Phase III clinical trial was performed in five military health centres. located in northwestern, central and southern Colombia. Volunteers with parasitological positive diagnosis (Giemsa-stained smears) of cutaneous leishmaniasis were included. A single thermotherapy session involving the application of 50°C at the center and active edge of each lesion. Meglumine antimoniate was administered intramuscularly at a dose of 20?mg Sb5/kg weight/day for 20?days.Both groups were comparable. The efficacy of thermotherapy was 64% (86/134 patients) by protocol and 58% (86/149) by intention-to-treat. For the meglumine antimoniate group, efficacy by protocol was 85% (103/121 patients) and 72% (103/143) by intention-to-treat, The efficacy between the treatments was statistically significant (p 0.01 and < 0.001) for analysis by intention to treat and by protocol, respectively. There was no difference between the therapeutic response with either treatment regardless of the Leishmania species responsible for infection. The side effects of meglumine antimoniate included myalgia, arthralgia, headache and fever. Regarding thermotherapy, the only side effect was pain at the lesion area four days after the initiation of treatment.Although the efficacy rate of meglumine antimoniate was greater than that of thermotherapy for the treatment of cutaneous leishmaniasis, the side effects were also greater. Those factors, added to the increased costs, the treatment adherence problems and the progressive lack of therapeutic response, make us consider thermotherapy as a first line treatment for cutaneous leishmaniasis.

Dataset Information

The compositional landscape of minicircle sequences isolated from active lesions and scars of American cutaneous leishmaniasis.

Publications

The compositional landscape of minicircle sequences isolated from active lesions and scars of American cutaneous leishmaniasis.

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