Dados do Trabalho

Título

The increase of canine extracellular vesicles correlates with the evolution of canine visceral leishmaniasis

Introdução

Visceral leishmaniasis is a public health problem, cause various symptoms, which can evolve to death. Domestic dogs are reservoirs with great epidemiological importance. Studies have shown the functions of extracellular vesicles (EVs) produced by eukaryotic cells. Among them include the carry of molecules and specialized functions in immune response. Most interactions between L. (L.) infantum infection and EVs from infected hosts are not understood.

Objetivo(s)

We studied production, morphology and protein content of EVs from serum of dogs with canine visceral leishmaniasis (CVL).

Material e Métodos

According to Surveillance/SP State, Andradina is endemic for VL. Clinical/laboratorial diagnoses for CVL in dogs are performed periodically in blood samples. Sera (n=56) of dogs were used to concentrate and analyze EVs. Out of them, 22 were healthy (Group I, before infection). The same 22 dogs were naturally infected before 2nd collection (6 month-Group II, infect). Group III-12 sera (4 dogs/3 collections each). Dogs were negative in the 1st collection. After 9 and 18 months (2nd and 3rd collection) dogs were infected. Sera were ultracentrifuged to recover EVs and characterized by: transmission electron microscopy (TEM); SDS-PAGE/silver stained; immunoblot; nanoparticle tracking analysis (NTA). Correlations among groups were determined by Mann–Whitney test.

Resultados e Conclusão

TEM/SDS-PAGE showed microvesicles and exosomes. Immunoblot evidenced the proteins CD63 and CD9. Results of NTA were transformed into the mean± SEM of EVs/mL. Group I had 1.7x1010 ± 3.5x109. After infection, the same dogs (Group II) increased EV production to 6.8x1010 ± 1.4x1010. Value differences were statistically significant at p<0.0001. Clearly it was possible to observe an increase of EVs after infection. The correlation between EV release and infection progression was evaluated in Group III. Mean values were: before CVL, 7.5x109 ± 2.3x109. After CVL, 2nd collection (9 months), 2.9x1010 ± 2.1x1010; and 3rd collection (18 months) 8.7x1010 ± 5.5x1010.Contrast of EV production in 1st and 3rd collections was statistically significant at p=0.286.These data suggest that concentrations of serum-derived EVs were able to distinguish infected dogs from healthy ones. Certainly, EVs produced by hosts participate in the unbalance of immune response and it opens a new light on the role of EVs in CVL, as demonstrated in other infectious diseases.

Palavras-chave

Extracellular vesicles
L. infantum
Canine visceral leishmaniasis