Leishmaniose visceral no Brasil:\ud evolução e desafios

The urbanization of visceral leishmaniasis in Brazil has been related to environmental changes, migration, interaction and spread of sylvatic reservoirs and infected dogs to areas with no transmission, and adaptation of the vector Lutzomyia longipalpis to the peridomiciliary environment. From 1980 to 2005, Brazil recorded 59,129 cases of visceral leishmaniasis, 82.5% of which in the Northeast region. Visceral leishmaniasis gradually spread to other regions of the country: in 1998 these other regions reported 15% of all cases, but by 2005 this proportion had increased to 44%. From 1998 to 2005, indigenous cases were reported in 1,904 different municipalities of the country (34.2%). Reservoir and vector control pose major challenges for disease control, since there is a need for better knowledge of vector behavior in urban areas, and control activities involve high operational costs. In recent years the Brazilian Ministry of Health has supported research on the laboratory diagnosis of infection and disease in humans and dogs, treatment of patients, evaluation of the effectiveness of control strategies, and development of new technologies that could contribute to the surveillance and control of visceral leishmaniasis in the country.A urbanização da leishmaniose visceral tem sido relacionada\ud a modificações ambientais causadas por\ud ações antrópicas, pelo rápido processo migratório, pela\ud interação e mobilização de reservatórios silvestres\ud e cães infectados para áreas sem transmissão, e pela\ud adaptação do vetor Lutzomiya longipalpis ao peridomicílio.\ud Entre 1980 e 2005, o Brasil registrou 59.129\ud casos de leishmaniose visceral, sendo 82,5% na Região\ud Nordeste. Gradativamente, a leishmaniose visceral expandiu-\ud se para as regiões Centro-Oeste, Norte e Sudeste,\ud passando de 15% dos casos em 1998 para 44% em\ud 2005. Entre 1998 e 2005 foram registrados casos autóctones\ud em 1.904 (34,2%) diferentes municípios brasileiros.\ud O controle vetorial e de reservatórios representam\ud os maiores desafios para o controle da doença, dado\ud a necessidade de melhor conhecer o comportamento\ud do vetor no ambiente urbano, as dificuldades operacionais\ud e o alto custo de execução. Nos últimos anos, o\ud Ministério da Saúde tem investido em pesquisas sobre\ud diagnóstico laboratorial humano e canino, tratamento\ud dos pacientes, avaliação da efetividade das estratégias\ud de controle, bem como de novas tecnologias que\ud possam contribuir na implementação das ações de vigilância\ud e controle da leishmaniose visceral no Brasil

Mechanisms involving Ang II and MAPK/ERK1/2 signaling pathways underlie cardiac and renal alterations during chronic undernutrition.

Several studies have correlated protein restriction associated with other nutritional deficiencies with the development of cardiovascular and renal diseases. The driving hypothesis for this study was that Ang II signaling pathways in the heart and kidney are affected by chronic protein, mineral and vitamin restriction.Wistar rats aged 90 days were fed from weaning with either a control or a deficient diet that mimics those used in impoverished regions worldwide. Such restriction simultaneously increased ouabain-insensitive Na+-ATPase and decreased (Na++K+)ATPase activity in the same proportion in cardiomyocytes and proximal tubule cells. Type 1 angiotensin II receptor (AT1R) was downregulated by that restriction in both organs, whereas AT2R decreased only in the kidney. The PKC/PKA ratio increased in both tissues and returned to normal values in rats receiving Losartan daily from weaning. Inhibition of the MAPK pathway restored Na+-ATPase activity in both organs. The undernourished rats presented expanded plasma volume, increased heart rate, cardiac hypertrophy, and elevated systolic pressure, which also returned to control levels with Losartan. Such restriction led to electrical cardiac remodeling represented by prolonged ventricular repolarization parameters, induced triggered activity, early after-depolarization and delayed after-depolarization, which were also prevented by Losartan.The mechanisms responsible for these alterations are underpinned by an imbalance in the PKC- and PKA-mediated pathways, with participation of angiotensin receptors and by activation of the MAPK/ERK1/2 pathway. These cellular and molecular alterations culminate in cardiac electric remodeling and in the onset of hypertension in adulthood

Na⁺-ATPase activity and MAPK pathway in heart (left panels) and kidney (right panels).

<p>(A, B) Na⁺-ATPase activity was measured in the four experimental groups in the absence or presence of 30 µM PD098059, as indicated. Results are mean ± SEM (n = 5) in assays carried out using different membrane preparations. (C, D) Representative immunoblottings of ERK1 in duplicate (upper panels), β-actin loading-controls for each blotting (middle panels) and densitometric representations (n = 8–10) (lower panels). (E, F) Representative immunoblottings of phospho-ERK1/2 in duplicate (upper panels), β-actin loading controls for each blotting (middle panels) and densitometric representations (n = 8–10) (lower panels). (G, H) phospho-ERK1/2∶ERK1 ratio (n = 8–10). Each phospho-ERK1/2∶ERK1 ratio value was calculated using the corresponding densitometric value obtained from the same lane. Different lowercase letters above the bars indicate statistically different mean values within the corresponding panel, assessed by one-way ANOVA followed by Tukey test. P values for ERK1 comparisons: P = 0.302 and 0.968 (heart and kidney, respectively, where no statistical differences were found among the four groups and Tukey test was not carried out). P values for phospho-ERK1/2 comparisons: P = 0.001–0.007 (heart, BRD Los against the other three groups, P = 0.928–0.999 for the comparisons among the other groups); P = 0.928 (kidney, where no statistical differences were found among the four groups and Tukey test was not carried out). P values for phospho-ERK1/2∶ERK1 ratio comparisons: P = 0.004–0.007 (heart, BRD Los against the other four groups, P = 0.995–0.999 for the comparisons among the other groups); P = 0.977 (kidney, no differences among the four groups).</p

Food and water intake.

<p>Food and water ingestion was recorded one day before sacrifice at 90 days of age at the end of a 24 h period. The animal groups were those described in the legend to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100410#pone-0100410-g002" target="_blank">Figure 2</a>. The rats were maintained in individual metabolic cages in the same conditions of light and temperature described in the Methods section of the main text. Simultaneous recording of body weight at the end of the period allowed correction of the data, as shown on the <i>abscissa</i>e. Different lowercase letters above the bars indicate statistically different mean values in panel B (P<0.05; n = 5).</p

Triggered activity, early after depolarization (EAD) and delayed after depolarization (DAD), was induced by chronic BRD intake.

<p>(A–D) Representative action potential traces after a train of 10 beats at BCLs of 200, 150 and 100 ms followed by a pause in the left ventricle of all studied groups. (C) Representative action potential traces from the BRD group show rate-dependent triggered activity during a pause (arrows) after a train of 10 beats at BCLs of 150 and 100 ms followed by a pause protocol. (D) Los prevented the appearance of BRD-induced triggered activity. (E) In right ventricle BRD induced late-phase 3 EAD and DAD at BCL 1000 ms (arrows).</p

Representative plasma amino acids analysis.

<p>The plasma was analyzed by high performance liquid chromatography (HPLC) as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100410#s2" target="_blank">Materials and Methods</a>. Abbreviations of the experimental groups are those defined in the legend to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100410#pone-0100410-g002" target="_blank">Figure 2</a>. The peaks were identified using individual amino acid standards that were run immediately after the plasma samples. Quantification and statistical analysis of the peaks are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100410#pone-0100410-g005" target="_blank">Figures 5</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100410#pone-0100410-g006" target="_blank">6</a>.</p

BRD induces increase in plasma levels of L-Serine and L-Alanine with simultaneous decrease in D-Serine and D-Alanine.

<p>Panels show values for each animal. Horizontal lines represent mean values (n = 6–8 blood samples from different rats of each group). Statistical differences were assessed by one-way ANOVA followed by Bonferroni adjustment for CTR vs. BRD, CTR vs. CTR Los, BRD vs. BRD Los, and CTR Los vs. BRD Los, as indicated.</p

BRD induced longer QT, QTc, Tpeak-Tend and action potential duration.

<p>The animal groups were as described for <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0100410#pone-0100410-g002" target="_blank">Figure 2</a>. (A) Representative traces of electrocardiograms show longer QT in the BRD group. (B) BRD induced ventricular repolarization disturbances, as summarized in the bar graph. Histograms show mean ± SEM. (C) Representative traces show longer left, but not right, ventricular action potential in BRD. (D) Longer ventricular action potential duration at 90% repolarization (APD₉₀) in the BRD group under different basic cycle lengths (BCL), as shown on the abscissae (panels B and D, n = 6–10). Different lowercase letters above the bars indicate statistically different mean values within the corresponding panel (P<0.05).</p

The increment of ouabain-resistant Na⁺-ATPase and the decrease of (Na⁺+K⁺)ATPase activities were similar in cardiomyocytes and renal proximal tubule cells of BRD rats, but the pumps were differentially modulated by Los.

<p>Upper: ouabain-insensitive Na⁺-ATPase (A, heart, n = 5; B, kidney, n = 5). Lower: (Na⁺+K⁺)ATPase (C, heart, n = 5; D, kidney, n = 5). Histograms show mean ± SEM. Different lowercase letters above the bars indicate statistically different mean values within the corresponding panel (P<0.05), assessed by one-way ANOVA followed by Tukey test for multiple comparisons.</p

Action potential parameters recorded in right endocardial ventricle preparation.

<p>RMP: Resting membrane potential. APA: Action potential amplitude; APD: Action potential duration. The results are expressed as mean ± SEM; n = 6 (CTR), n = 5 (BRD), n = 4 (CTR Los), n = 5 (BRD Los). No statistical differences were found among groups.</p