RESUMO
We previously reported that ciprofloxacin (CIP) free lung interstitial concentrations are decreased by biofilm-forming Pseudomonas aeruginosa pulmonary chronic (14 d) infection. To get a better understanding on the influence of infection on CIP lung distribution, in the present study free lung interstitial fluid and epithelial lining fluid (ELF) concentrations were determined by microdialysis in biofilm-forming P. aeruginosa acutely (2 d) and chronically infected (14 d) Wistar rats following CIP 20 mg/kg i.v. bolus dosing. A popPK model was developed, using NONMEM® (version 7.4.3) with FOCE+I, with plasma data described as a three-compartment model with first-order elimination. For lung data inclusion, the model was expanded to four compartments and ELF concentrations were described as a fraction of lung levels estimated as a distribution factor (ƒD). Acute infection had a minor impact on plasma and lung CIP distribution and both infection stages did not alter ELF drug penetration. Probability of target attainment of ƒAUC0-24/MIC ≥ 90 using 20 mg q8h, equivalent to 400 mg q8h in humans, showed that CIP free concentrations in plasma are adequate to successfully treat lung infections. However, lung and ELF free interstitial concentrations might be insufficient to result in efficacious treatment of biofilm-forming P. aeruginosa chronic infection. However, lung and ELF free interstitial concentrations might be insufficient to result in efficacious treatment of biofilm-forming P. aeruginosa chronic infection.
Assuntos
Ciprofloxacina , Infecções por Pseudomonas , Humanos , Ratos , Animais , Antibacterianos , Pseudomonas aeruginosa , Infecção Persistente , Ratos Wistar , Infecções por Pseudomonas/tratamento farmacológico , Pulmão , Biofilmes , Testes de Sensibilidade MicrobianaRESUMO
Burkholderia contaminans, a species of the Burkholderia cepacia complex-prevalent in certain Latin-American and European countries-can cause chronic pulmonary infection in persons with cystic fibrosis. Our aim was to gain insights into long-term lung infections with a focus on correlating how bacterial phenotypic traits in the chronic infection impact on patients' clinical outcome. Genotypic characteristics of 85 B. contaminans isolates recovered from 70 patients were investigated. For 16 of those patients, the clinical status and bacterial phenotypic characteristics, e.g. several virulence factors, phenotypic variants, and the antimicrobial susceptibility pattern, were evaluated. Two clones were found in the whole bacterial population: (i) the multiresistant ST 872 PCR-recA-RFLP-HaeIII-K-pattern clone, which carries a pathogenic island homologous to BcenGI11 of B. cenocepacia J2315, and (ii) the ST 102 PCR-recA-RFLP-HaeIII-AT-pattern clone. The emergence of certain bacterial phenotypes in the chronic infection such as the nonmucoid phenotype, small colony variants, brownish pigmented colonies, and hypermutators, proved to be, together with coinfection with Pseudomonas aeruginosa, the possible markers of more challenging infections and poor prognosis. The presence of cocolonizers and the bacterial phenotypes that are especially adapted to persist in long-term respiratory tract infections have a crucial role in patients' clinical outcomes.
Assuntos
Infecções por Burkholderia , Complexo Burkholderia cepacia , Fibrose Cística , Pneumonia , Humanos , Infecção Persistente , Fibrose Cística/complicações , Fibrose Cística/microbiologia , Pulmão/microbiologia , Fenótipo , Infecções por Burkholderia/microbiologiaRESUMO
Excessive use of medications, including the antiparasitic drug ivermectin, can lead to bacterial gut dysbiosis, an imbalance in the intestinal microbiome, which in turn may increase or decrease susceptibility to infectious processes. To better understand the effects of continuous ivermectin usage on the gut bacterial community, C57BL/6 isogenic mice were treated by gavage with ivermectin or saline. Ivermectin-induced bacterial gut dysbiosis is characterized by a decrease in Bacteroidetes, Firmicutes, Proteobacteria and Tenericutes and an increase in species of the phylum Verrucomicrobia. A pro-inflammatory immunostimulatory caecal content, as well as disruption of caecal tissue organization and liver tissue damage, was observed in mice with gut dysbiosis. However, ivermectin-induced gut dysbiosis did not lead to acute susceptibility to Pseudomonas aeruginosa lung infection: infected mice with and without gut dysbiosis showed similar rates of recovery of viable bacteria in organs, histopathology and differential cytokine expression in the lung. Therefore, an extension of liver damage was observed in ivermectin-treated and P. aeruginosa-infected mice, which was exacerbated by infection.
Assuntos
Ivermectina , Pseudomonas aeruginosa , Animais , Camundongos , Ivermectina/efeitos adversos , Disbiose/induzido quimicamente , Disbiose/microbiologia , Camundongos Endogâmicos C57BL , Pulmão , FígadoRESUMO
BACKGROUND: We investigated the relationship between inducible nitric oxide synthase (iNOS) and arginase pathways, cytokines, macrophages, oxidative damage and lung granulomatous inflammation in S. mansoni-infected and doxycycline-treated mice. METHODS: Swiss mice were randomized in four groups: (i) uninfected, (ii) infected with S. mansoni, (iii) infected + 200 mg/kg praziquantel (Pzt), (iv) and (v) infected + 5 and 50 mg/kg doxycycline. Pzt (reference drug) was administered in a single dose and doxycycline for 60 days. RESULTS: S. mansoni-infection determined extensive lung inflammation, marked recruitment of M2 macrophages, cytokines (IL-4, IL-5, IFN-γ, TNF-α) upregulation, intense eosinophil peroxidase (EPO) levels, arginase expression and activity, reduced iNOS expression and nitric oxide (NO) production. The higher dose of doxycycline aggravated lung granulomatous inflammation, downregulating IL-4 levels and M2 macrophages recruitment, and upregulating iNOS expression, EPO, NO, IFN-γ, TNF-α, M1 macrophages, protein carbonyl and malondialdehyde tissue levels. The number and size of granulomas in doxycycline-treated animals was higher than untreated and Pzt-treated mice. Exudative/productive granulomas were predominant in untreated and doxycycline-treated animals, while fibrotic/involutive granulomas were more frequent in Pzt-treated mice. The reference treatment with Pzt attenuated all these parameters. CONCLUSION: Our findings indicated that doxycycline aggravated lung granulomatous inflammation in a dose-dependent way. Although Th1 effectors are protective against several intracellular pathogens, effective schistosomicidal responses are dependent of the Th2 phenotype. Thus, doxycycline contributes to the worsening of lung granulomatous inflammation by potentiating eosinophils influx and downregulating Th2 effectors, reinforcing lipid and protein oxidative damage in chronic S. mansoni infection.
Assuntos
Doxiciclina , Esquistossomose , Camundongos , Animais , Óxido Nítrico Sintase Tipo II/metabolismo , Doxiciclina/farmacologia , Arginase/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Interleucina-4/metabolismo , Citocinas/metabolismo , Pulmão , Estresse Oxidativo , Inflamação/tratamento farmacológico , Granuloma , Óxido Nítrico/metabolismoRESUMO
Macrophages are a heterogeneous population of myeloid cells with phenotype and function modulated according to the microenvironment in which they are found. The lung resident macrophages known as Alveolar Macrophages (AM) and Interstitial Macrophages (IM) are localized in two different compartments. During lung homeostasis, macrophages can remove inhaled particulates, cellular debris and contribute to some metabolic processes. Macrophages may assume a pro-inflammatory phenotype after being classically activated (M1) or anti-inflammatory when being alternatively activated (M2). M1 and M2 have different transcription profiles and act by eliminating bacteria, viruses and fungi from the host or repairing the damage triggered by inflammation, respectively. Nevertheless, macrophages also may contribute to lung damage during persistent inflammation or continuous exposure to antigens. In this review, we discuss the origin and function of pulmonary macrophages in the context of homeostasis, infectious and non-infectious lung diseases.
Assuntos
Macrófagos Alveolares , Animais , Anti-Inflamatórios , Pulmão , Ativação de Macrófagos , MacrófagosRESUMO
The emergence of life-threatening zoonotic diseases caused by betacoronaviruses, including the ongoing coronavirus disease 19 (COVID-19) pandemic, has highlighted the need for developing preclinical models mirroring respiratory and systemic pathophysiological manifestations seen in infected humans. Here, we showed that C57BL/6J wild-type mice intranasally inoculated with the murine betacoronavirus murine hepatitis coronavirus 3 (MHV-3) develop a robust inflammatory response leading to acute lung injuries, including alveolar edema, hemorrhage, and fibrin thrombi. Although such histopathological changes seemed to resolve as the infection advanced, they efficiently impaired respiratory function, as the infected mice displayed restricted lung distention and increased respiratory frequency and ventilation. Following respiratory manifestation, the MHV-3 infection became systemic, and a high virus burden could be detected in multiple organs along with morphological changes. The systemic manifestation of MHV-3 infection was also marked by a sharp drop in the number of circulating platelets and lymphocytes, besides the augmented concentration of the proinflammatory cytokines interleukin 1 beta (IL-1ß), IL-6, IL-12, gamma interferon (IFN-γ), and tumor necrosis factor (TNF), thereby mirroring some clinical features observed in moderate and severe cases of COVID-19. Importantly, both respiratory and systemic changes triggered by MHV-3 infection were greatly prevented by blocking TNF signaling, either via genetic or pharmacologic approaches. In line with this, TNF blockage also diminished the infection-mediated release of proinflammatory cytokines and virus replication of human epithelial lung cells infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Collectively, results show that MHV-3 respiratory infection leads to a large range of clinical manifestations in mice and may constitute an attractive, lower-cost, biosafety level 2 (BSL2) in vivo platform for evaluating the respiratory and multiorgan involvement of betacoronavirus infections. IMPORTANCE Mouse models have long been used as valuable in vivo platforms to investigate the pathogenesis of viral infections and effective countermeasures. The natural resistance of mice to the novel betacoronavirus SARS-CoV-2, the causative agent of COVID-19, has launched a race toward the characterization of SARS-CoV-2 infection in other animals (e.g., hamsters, cats, ferrets, bats, and monkeys), as well as adaptation of the mouse model, by modifying either the host or the virus. In the present study, we utilized a natural pathogen of mice, MHV, as a prototype to model betacoronavirus-induced acute lung injure and multiorgan involvement under biosafety level 2 conditions. We showed that C57BL/6J mice intranasally inoculated with MHV-3 develops severe disease, which includes acute lung damage and respiratory distress that precede systemic inflammation and death. Accordingly, the proposed animal model may provide a useful tool for studies regarding betacoronavirus respiratory infection and related diseases.
Assuntos
Infecções por Coronavirus/patologia , Modelos Animais de Doenças , Pulmão/patologia , Vírus da Hepatite Murina/patogenicidade , Animais , Linhagem Celular , Contenção de Riscos Biológicos , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Citocinas/metabolismo , Humanos , Inflamação , Fígado/patologia , Fígado/virologia , Pulmão/virologia , Camundongos , Vírus da Hepatite Murina/efeitos dos fármacos , Vírus da Hepatite Murina/fisiologia , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/patogenicidade , SARS-CoV-2/fisiologia , Transdução de Sinais/efeitos dos fármacos , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/metabolismo , Replicação Viral/efeitos dos fármacosRESUMO
Multiple infectious diseases lead to impaired lung function. Revealing the cellular mechanisms involved in this impairment is crucial for the understanding of how the lungs shift from a physiologic to a pathologic state in each specific condition. In this context, we explored the pathogenesis of Paracoccidioidomycosis, which affects pulmonary functioning. The presence of cells expressing Nestin-GFP has been reported in different tissues, and their roles as tissue-specific progenitors have been stablished in particular organs. Here, we explored how Nestin-GFP+ cells are affected after lung infection by Paracoccidioides brasiliensis, a model of lung granulomatous inflammation with fibrotic outcome. We used Nestin-GFP transgenic mice, parabiosis surgery, confocal microscopy and flow cytometry to investigate the participation of Nestin-GFP+ cells in Paracoccidioides brasiliensis pathogenesis. We revealed that these cells increase in the lungs post-Paracoccidioides brasiliensis infection, accumulating around granulomas. This increase was due mainly to Nestin-GPF+ cells derived from the blood circulation, not associated to blood vessels, that co-express markers suggestive of hematopoietic cells (Sca-1, CD45 and CXCR4). Therefore, our findings suggest that circulating Nestin-GFP+ cells participate in the Paracoccidioides brasiliensis pathogenesis in the lungs.
Assuntos
Pulmão , Animais , Camundongos , Nestina/genética , Paracoccidioides/genéticaRESUMO
Pseudomonas aeruginosa is considered an opportunistic pathogen of great clinical importance. The clearance of this bacterium occurs through recognition of the pathogen by innate immune system receptors, leading to a lung inflammatory response. However, this response must be controlled via immunoregulatory pathways. In this study, we evaluate the role of endogenous murine IL-10 after acute infection with the virulent strain P. aeruginosa PA14. To assess the role of IL-10, intratracheal infection with the PA14 strain was performed in C57BL/6 or IL-10 KO mice. The PA14 strain was recovered in both types of animals, although IL-10 KO mice presented a higher number of viable bacteria in the lung when compared to the C57BL/6 group. Histopathological and stereological analyses showed that IL-10 KO mice had higher tissue damage and inflammatory infiltrate when compared to control animals. The activity of MMP-9 but not MMP-2, as well as IL-6 and TNF-α expression, were augmented in the lungs of infected animals and was much more evident in IL-10 KO animals when compared to the other analyzed groups. This work indicates that endogenous IL-10 control P. aeruginosa infection, the expression of pro-inflammatory genes, MMP-9 activity and histopathological processes of the infectious process in question.
Assuntos
Interleucina-10/imunologia , Pulmão , Infecções por Pseudomonas/imunologia , Pseudomonas aeruginosa/imunologia , Animais , Imunidade , Pulmão/imunologia , Pulmão/patologia , Metaloproteinase 9 da Matriz/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos KnockoutRESUMO
Oxygen is fundamental to the life of aerobic organisms and is not always available to Paracoccidioides cells. During the life cycle stages, reduced oxygen levels directly affect general metabolic processes and oxygen adaptation mechanisms may play a fundamental role on fungal ability to survive under such condition. Heme proteins can bind to oxygen and participate in important biological processes. Several fungi, including Paracoccidioides, express a heme-binding globin (fungoglobin - FglA) presumable to regulate fungal adaptation to hypoxia. However, the characterization of fungoglobin in Paracoccidioides spp. has not yet been performed. In this study, we predicted the structure of fungoglobin and determined its level of expression during hypoxic-mimetic conditions. Genomic screening revealed that the fungoglobin gene is conserved in all species of the Paracoccidioides genus. Molecular modeling showed biochemical and biophysical characteristics that support the hypothesis that FglA binds to the heme group and oxygen as well. The fungoglobin transcript and proteins are expressed at higher levels at the early treatment time, remaining elevated while oxygen is limited. A P. brasiliensis fglA knockdown strain depicted reduced growth in hypoxia indicating that this protein can be essential for growth at low oxygen. Biochemical analysis confirmed the binding of fungoglobin to heme. Initial analyzes were carried out to establish the relationship between FlglA and iron metabolism. The FglA transcript was up regulated in pulmonary infection, suggesting its potential role in the disease establishment. We believe that this study can contribute to the understanding of fungal biology and open new perspectives for scientific investigations.
Assuntos
Proteínas Fúngicas/genética , Heme/genética , Hemeproteínas/genética , Paracoccidioides/genética , Aerobiose/genética , Hipóxia Celular/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica/genética , Heme/metabolismo , Hemeproteínas/metabolismo , Oxigênio/metabolismo , Paracoccidioides/metabolismoRESUMO
Chronic ethanol consumption is a leading cause of mortality worldwide, with higher risks to develop pulmonary infections, including Aspergillus infections. Mechanisms underlying increased susceptibility to infections are poorly understood. Chronic ethanol consumption induced increased mortality rates, higher Aspergillus fumigatus burden and reduced neutrophil recruitment into the airways. Intravital microscopy showed decrease in leukocyte adhesion and rolling after ethanol consumption. Moreover, downregulated neutrophil activation and increased levels of serum CXCL1 in ethanol-fed mice induced internalization of CXCR2 receptor in circulating neutrophils. Bone marrow-derived neutrophils from ethanol-fed mice showed lower fungal clearance and defective reactive oxygen species production. Taken together, results showed that ethanol affects activation, recruitment, phagocytosis and killing functions of neutrophils, causing susceptibility to pulmonary A. fumigatus infection. This study establishes a new paradigm in innate immune response in chronic ethanol consumers.
Alcoholism is a chronic disease that has many damaging effects on the body. Over long periods, excessive alcohol intake weakens the immune system, putting consumers at increased risk of getting lung infections such as pneumonia. Some forms of pneumonia can be caused by the fungus Aspergillus fumigatus. This microbe does not tend to be a problem for healthy individuals, but it can be fatal for those with impaired immune systems. Here, Malacco et al. wanted to find out why excessive alcohol consumers are more prone to pneumonia. To test this, the researchers used two groups of mice that were either fed plain water or water containing ethanol. After 12 weeks, both groups were infected with Aspergillus fumigatus. The results showed that alcohol-fed mice were more susceptible to the infection caused by strong inflammation of the lungs. Normally, the immune system confronts a lung infection by activating a group of defense cells called neutrophils, which travel through the blood system to the infection site. Once in the right spot, neutrophils get to work by releasing toxins that kill the fungus. Malacco et al. discovered that after chronic alcohol consumption, neutrophils were less reactive to inflammatory signals and less likely to reach the lungs. They were also less effective in dealing with the infection. Neutrophil released fewer toxins and were thus less able to kill the microbial cells. These findings demonstrate for the first time how alcohol can affect immune cells during infection and pave the way for new possibilities to prevent fatal lung infections in excessive alcohol consumers. A next step would be to identify how alcohol acts on other processes in the body and to find a way to modulate or even revert the changes it causes.
Assuntos
Aspergilose/imunologia , Aspergillus fumigatus/imunologia , Etanol/efeitos adversos , Pneumopatias Fúngicas/imunologia , Neutrófilos/efeitos dos fármacos , Doença Aguda , Animais , Aspergilose/induzido quimicamente , Aspergilose/patologia , Antígeno CD11b/metabolismo , Quimiotaxia/efeitos dos fármacos , Citocinas/imunologia , Suscetibilidade a Doenças , Inflamação/induzido quimicamente , Selectina L/metabolismo , Pneumopatias Fúngicas/induzido quimicamente , Pneumopatias Fúngicas/microbiologia , Pneumopatias Fúngicas/patologia , Linfócitos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/imunologia , Fagocitose/efeitos dos fármacos , Receptores de Interleucina-8B/metabolismo , Explosão Respiratória/efeitos dos fármacosRESUMO
BACKGROUND: The low rate of nontuberculous mycobacteria (NTM) among Brazilian patients with cystic fibrosis (CF) may be due to cross-reactive Bacille Calmette-Guérin (BCG) vaccination. In the present pilot study, we aimed to compare the lymphocyte responses against Mycobacterium tuberculosis(Mtb) and Mycobacterium bovis (BCG) in BCG-vaccinated CF patients and healthy controls. METHODS: The lymphocyte responses of CF patients (n = 10) and healthy controls (n = 10) were assessed in terms of lymphocyte proliferation index (LPI), using flow cytometry. Median rates of each cell subtype - CD4, CD8, γδ T cells and CD19 (B) cells - were also determined. RESULTS: Median LPIs (CF vs. controls) were 22.9% vs. 13.0% (p = 0.481) and 23.1% vs. 17.6% (p = 0.481), upon stimulation with Mtb and BCG, respectively. Both groups had a predominant CD4 T cell response to Mtb (median rate = 82.5% vs. 79.7%; p = 0.796) and BCG (LPI = 84.3% vs. 83.0%; p = 0.853), which were significantly higher than the CD8, CD19 and γδ responses within both groups. CF patients tended to have a higher CD8 T cell response upon stimulation with the phytohemagglutinin mitogen than healthy controls (median rate = 42.8% vs. 31.7%, p = 0.075). CONCLUSION: The responses of BCG-vaccinated CF patients to Mtb and BCG are at least similar to those of healthy individuals. These are probably memory responses elicited by the BCG vaccination, which can cross-react with NTM and may explain the low frequency of NTM lung infection in our CF center.
Assuntos
Vacina BCG , Fibrose Cística , Imunidade Inata , Ativação Linfocitária/imunologia , Subpopulações de Linfócitos/imunologia , Infecções por Mycobacterium não Tuberculosas , Tuberculose/prevenção & controle , Adolescente , Vacina BCG/imunologia , Vacina BCG/uso terapêutico , Brasil/epidemiologia , Fibrose Cística/diagnóstico , Fibrose Cística/epidemiologia , Fibrose Cística/imunologia , Feminino , Humanos , Imunidade Inata/efeitos dos fármacos , Imunidade Inata/imunologia , Memória Imunológica , Masculino , Infecções por Mycobacterium não Tuberculosas/epidemiologia , Infecções por Mycobacterium não Tuberculosas/prevenção & controle , Mycobacterium bovis/imunologia , Mycobacterium tuberculosis/imunologia , Projetos Piloto , Vacinação/métodosRESUMO
Cationic antimicrobial peptides (AMPs) are short linear amino acid sequences, which display antimicrobial activity against a wide range of bacterial species. They are promising novel antimicrobials since they have shown bactericidal effects against multiresistant bacteria. Their amphiphilic structure with hydrophobic and cationic regions drives their interaction with anionic bacterial cytoplasmic membranes, which leads to their disruption. In this work two synthetic designed AMPs, P5 and P6.2, which have been previously analyzed in their ability to interact with bacterial or eukaryotic membranes, were evaluated in their anti-biofilm and in vivo antibacterial activity. In a first step, a time-kill kinetic assay against P. aeruginosa and S. aureus and a curve for hemolytic activity were performed in order to determine the killing rate and the possible undesirable toxic effect, respectively, for both peptides. The biofilm inhibitory activity was quantified at sub MIC concentrations of the peptides and the results showed that P5 displayed antibiofilm activity on both strains while P6.2 only on S. aureus. Scanning electron microscopy (SEM) of bacteria treated with peptides at their MIC revealed protruding blisters on Gam-negative P. aeruginosa strain, but almost no visible surface alteration on Gram-positive S. aureus. These micrographs highlighted different manifestations of the membrane-disrupting activity that these kinds of peptides possess. Finally, both peptides were analyzed in vivo, in the lungs of neutropenic mice previously instilled with P. aeruginosa. Mice lungs were surgically extracted and bacteria and pro-inflammatory cytokines (IL-ß, IL-6 and TNF-α) were quantified by colony forming units and ELISA, respectively. Results showed that instillation of the peptides produced a significant decrease in the number of living bacteria in the lungs, concomitant with a decrease in pro-inflammatory cytokines. Overall, the results presented here suggest that these two new peptides could be good candidates for future drug development for anti-biofilm and anti-infective therapy.
Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Biofilmes/efeitos dos fármacos , Aminoácidos/química , Animais , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Fenômenos Químicos , Relação Dose-Resposta a Droga , Feminino , Camundongos , Testes de Sensibilidade Microbiana , Pneumonia Bacteriana/metabolismo , Pneumonia Bacteriana/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/ultraestrutura , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/ultraestruturaRESUMO
Pseudomonas aeruginosa is one of the most common opportunistic pathogens causing respiratory infections in hospitals. Vancomycin, the antimicrobial agent usually used to treat bacterial nosocomial infections, is associated with gut dysbiosis. As a lung-gut immunologic axis has been described, this study aimed to evaluate both the immunologic and histopathologic effects on the lungs and the large intestine resulting from vancomycin-induced gut dysbiosis in the P. aeruginosa pneumonia murine model. Metagenomic analysis demonstrated that vancomycin-induced gut dysbiosis resulted in higher Proteobacteria and lower Bacteroidetes populations in feces. Given that gut dysbiosis could augment the proinflammatory status of the intestines leading to a variety of acute inflammatory diseases, bone marrow-derived macrophages were stimulated with cecal content from dysbiotic mice showing a higher expression of proinflammatory cytokines and lower expression of IL-10. Dysbiotic mice showed higher levels of viable bacteria in the lungs and spleen when acutely infected with P. aeruginosa, with more lung and cecal damage and increased IL-10 expression in bronchoalveolar lavage. The susceptible and tissue damage phenotype was reversed when dysbiotic mice received fecal microbiota transplantation. In spite of higher recruitment of CD11b+ cells in the lungs, there was no higher CD80+ expression, DC+ cell amounts or proinflammatory cytokine expression. Taken together, our results indicate that the bacterial community found in vancomycin-induced dysbiosis dysregulates the gut inflammatory status, influencing the lung-gut immunologic axis to favor increased opportunistic infections, for example, by P. aeruginosa.
Assuntos
Disbiose/etiologia , Microbioma Gastrointestinal/imunologia , Intestinos/microbiologia , Pulmão/microbiologia , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/imunologia , Vancomicina/toxicidade , Animais , Antibacterianos/toxicidade , Modelos Animais de Doenças , Disbiose/patologia , Fezes/microbiologia , Microbioma Gastrointestinal/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Intestinos/imunologia , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/imunologia , Pseudomonas aeruginosa/efeitos dos fármacosRESUMO
Cryptococcus gattii is the causative agent of cryptococcosis infection that can lead to pneumonia and meningitis in immunocompetent individuals. The molecular basis of the pathogenic process and impact on the host biochemistry are poorly understood and remain largely unknown. In this context, a comparative proteomic analysis was performed to investigate the response of the host during an infection caused by C. gattii. Lungs of experimentally infected rats were analyzed by shotgun proteomics to identify differentially expressed proteins induced by C. gattii clinical strain. The proteomic results were characterized using bioinformatic tools, and subsequently, the molecular findings were validated in cell culture and lungs of infected animals. A dramatic change was observed in protein expression triggered by C. gattii infection, especially related to energy metabolism. The main pathways affected include aerobic glycolysis cycle, TCA cycle, and pyrimidine and purine metabolism. Analyses in human lung fibroblast cells confirmed the altered metabolic status found in infected lungs. Thus, it is clear that C. gattii infection triggers important changes in energy metabolism leading to the activation of glycolysis and lactate accumulation in lung cells, culminating in a cancerlike metabolic status known as the Warburg effect. The results presented here provide important insights to better understand C. gattii molecular pathogenesis.
Assuntos
Criptococose/metabolismo , Metabolismo Energético/fisiologia , Glicólise/fisiologia , Pulmão/metabolismo , Proteoma/metabolismo , Proteômica/métodos , Animais , Linhagem Celular , Criptococose/microbiologia , Cryptococcus gattii/fisiologia , Modelos Animais de Doenças , Fibroblastos/citologia , Fibroblastos/metabolismo , Fibroblastos/microbiologia , Interações Hospedeiro-Patógeno , Humanos , Pulmão/microbiologia , Masculino , Ratos WistarRESUMO
PURPOSE OF REVIEW: Pulmonary cytomegalovirus (CMV) infection is a potential lethal disease in children, but it remains a diagnostic challenge. The differentiation between latent CMV infections with viral shedding and active infections is difficult and may lead to false positives in bronchoalvolar lavage (BAL) PCR detection. This review summarizes current diagnostic approaches for CMV lung infection in children including progress in the identification of underlying immune defects linked to this condition. RECENT FINDINGS: There is increasing literature supporting that the combined assessment of host risk factors and lung disease pattern is essential for the diagnosis of pulmonary CMV infection in children. The most important host risk factor is an immunecompromised state that has expanded from primary or acquired immunodeficiency (e.g., HIV) to include a myriad of immune-dysregulation syndromes (e.g., CTLA4, PIK3 defects). Newborns, paricularly those born premature, are also a high-risk group. At the pulmonary level, active CMV infection is typically characterized by alveolar compromise leading to hypoxemia, ground-glass opacities, and intra-alveolar infiltrates with CMV inclusions in lung biopsy. The identification of active CMV lung infection should trigger additional evaluation of immune defects (primary or secondary) impairing T and NK cell function or innate antiviral responses as well as other immune dysregulation disorders. Lung CMV infections in children are more prevalent in immunocompromised hosts and premature newborns. Lung CMV infections should prompt further investigation into conditions altering immune mechanisms usually in place to contain CMV infections. Common clinical and radiological patterns such as hypoxemia and ground-glass pulmonary opacities may allow early identification and treatment of CMV lung infection and underlying causes in the pediatric population.
RESUMO
Pneumonia is one of the leading causes of death and mortality worldwide. The inflammatory responses that follow respiratory infections are protective leading to pathogen clearance but can also be deleterious if unregulated. The microbiota is known to be an important protective barrier against infections, mediating both direct inhibitory effects against the potential pathogen and also regulating the immune responses contributing to a proper clearance of the pathogen and return to homeostasis. GPR43 is one receptor for acetate, a microbiota metabolite shown to induce and to regulate important immune functions. Here, we addressed the role of GPR43 signaling during pulmonary bacterial infections. We have shown for the first time that the absence of GPR43 leads to increased susceptibility to Klebsiella pneumoniae infection, which was associated to both uncontrolled proliferation of bacteria and to increased inflammatory response. Mechanistically, we showed that GPR43 expression especially in neutrophils and alveolar macrophages is important for bacterial phagocytosis and killing. In addition, treatment with the GPR43 ligand, acetate, is protective during bacterial lung infection. This was associated to reduction in the number of bacteria in the airways and to the control of the inflammatory responses. Altogether, GPR43 plays an important role in the "gut-lung axis" as a sensor of the host gut microbiota activity through acetate binding promoting a proper immune response in the lungs.
Assuntos
Infecções por Klebsiella/imunologia , Klebsiella pneumoniae , Receptores Acoplados a Proteínas G/imunologia , Animais , Líquido da Lavagem Broncoalveolar/citologia , Líquido da Lavagem Broncoalveolar/imunologia , Citocinas/imunologia , Macrófagos Alveolares/imunologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neutrófilos/imunologia , Fagocitose , Receptores Acoplados a Proteínas G/genéticaRESUMO
P. aeruginosa chronic lung infection is the major cause of morbidity and mortality in patients with cystic fibrosis (CF), and is characterized by a biofilm mode of growth, increased levels of specific IgG antibodies and immune complex formation. However, despite being designed to combat this infection, such elevated humoral response is not associated with clinical improvement, pointing to a lack of anti-pseudomonas effectiveness. The mode of action of specific antibodies, as well as their structural features, and even the background involving B-cell production, stimulation and differentiation into antibody-producing cells in the CF airways are poorly understood. Thus, the aim of this review is to discuss studies that have addressed the intrinsic features of the humoral immune response and provide new insights regarding its insufficiency in the CF context.
Assuntos
Biofilmes , Fibrose Cística/imunologia , Imunidade Humoral , Infecções por Pseudomonas/prevenção & controle , Pseudomonas aeruginosa , Infecções Respiratórias/prevenção & controle , Fibrose Cística/microbiologia , Fibrose Cística/terapia , Humanos , Infecções por Pseudomonas/etiologia , Infecções Respiratórias/etiologiaRESUMO
Más de la mitad de los pacientes con infección por virus de inmunodeficiencia humana (VIH) pueden tener compromiso pulmonar en el transcurso de su vida. Este puede ser multicausal y las infecciones oportunistas son las principales, sin embargo, las causas no infecciosas no son menos importantes. Objetivo: Describir las características del compromiso pulmonar en pacientes hospitalizados con infección por VIH. Metodología: Estudio descriptivo observacional. Resultados: Se incluyó a 63 pacientes, el 85,7% fueron hombres. La edad promedio fue 40,6 ± 12 años. El 21,4% tuvieron antecedente de promiscuidad sexual y 28,6% fueron hombres con sexo con hombres. Se identificó tabaquismo en 60,3%, alcoholismo en 52,4% y consumo de drogas en 20,6%. El 23,8% tuvo historia de tuberculosis. Al ingreso, el 79,4% tenía sida, el recuento promedio de CD4 fue 138,5 ± 17,7 células/mm3 y el 49,2% tenía CD4 < 100 células/mm3. Las principales comorbilidades fueron: enfermedad neoplásica 20,6%, diarrea crónica 19%, EPOC 6,3% y diabetes mellitus 3,2%. Los principales síntomas al ingreso fueron: respiratorios 66,7%, gastrointestinales 47,6% y neurológicos 34,9%. Los principales oportunistas documentados fueron Mycobacterium spp, H. capsulatum y P. jirovecii. El sarcoma de Kaposi, la enfermedad lifoproliferativa y la EPOC fueron causas de compromiso no infeccioso. Los principales hallazgos radiográficos fueron: infiltrados intersticiales (42,9%), compromiso pleural (23,8%) y lesiones cavitarias (7,9%). El compromiso multilobar fue evidente en el 15,9%. Las principales complicaciones fueron falla respiratoria, disfunción orgánica múltiple y falla renal aguda. El 19% requirió ingreso a UCI y, de estos, el 83,3% necesitó ventilación mecánica. La estancia hospitalariapromedio fue de 18 ± 20 días y la mortalidad del 17,5%. Discusión: Las infecciones por oportunistas son las principales causas de compromiso pulmonar y, dentro de estas, las causadas por micobacterias. Puede ocurrir más de una infección oportunista simultáneamente, pero en nuestra población fueron infrecuentes. Las causas noinfecciosas también son importantes.
More than a half of patients with HIV infection have pulmonary involvement throug-hout their lives. Opportunistic infections are the main cause; however, many patients havenoninfectious pulmonary involvement. Objective: To describe the characteristics of pulmonary involvement in inpatients with HIVinfection.Methods: Descriptive observational study. Results: A total of 63 patients were included, and 85.7% were men. The average age was40.6 ± 12 years. Some 21.4% had a history of sexual promiscuity and 28.6% were men whohad sex with men. Smoking was found in 60.3%, alcoholism in 52.4% and drug abuse in 20.6%.A tuberculosis history was documented in 23.8% of patients. At admission, 79.4% had AIDS, themean CD4 count was 138.5 ± 17.7 cells/mm3and 49.2% had CD4 counts < 100 cells/mm3. Majorcomorbidities included neoplastic disease in 20.6%, chronic diarrhea in 19%, COPD in 6.3% anddiabetes in 3.2%. Major opportunistic agents were Mycobacterium spp, H. capsulatum and P.jirovecii. Kaposi's sarcoma, lymphoproliferative disease and COPD were causes of noninfectiouspulmonary involvement. The main radiographic findings included interstitial infiltrates in 42.9%,pleural involvement in 23.8%, alveolar infiltrates in 7.9% and cavitary lesions in 7.9%. Multilobarcompromise was evident in 15.9% of the patients. The major complications were respiratoryfailure, multiple organ dysfunction and acute renal failure. Some 19% required care in the ICUand 83.3% of these required mechanical ventilation. The mean stay was 18 ± 20 days and themortality was 17.5%. Discussion: Opportunistic infections are the main causes of lung involvement and mycobacterialdiseases were most frequent. Mycobacterial diseases can occur simultaneously with an oppor-tunistic infection, but in our series this was infrequent. Non-infectious diseases are importantbut are less common.
Assuntos
Humanos , Masculino , Adulto , Pessoa de Meia-Idade , Infecções Respiratórias , HIV , Pneumopatias , Infecções Oportunistas , Síndrome da Imunodeficiência Adquirida , Colômbia , InfecçõesRESUMO
Neutrophil extracellular traps (NETs) arise from the release of granular and nuclear contents of neutrophils in the extracellular space in response to different classes of microorganisms, soluble factors, and host molecules. NETs are composed by decondensed chromatin fibers coated with antimicrobial granular and cytoplasmic proteins, such as myeloperoxidase, neutrophil elastase (NE), and α-defensins. Besides being expressed on NET fibers, NE and MPO also regulate NET formation. Furthermore, histone deimination by peptidylarginine deiminase 4 (PAD4) is a central step to NET formation. NET formation has been widely demonstrated to be an effective mechanism to fight against invading microorganisms, as deficiency in NET release or dismantling NET backbone by bacterial DNases renders the host susceptible to infections. Therefore, the primary role of NETs is to prevent microbial dissemination, avoiding overwhelming infections. However, an excess of NET formation has a dark side. The pathogenic role of NETs has been described for many human diseases, infectious and non-infectious. The detrimental effect of excessive NET release is particularly important to lung diseases, because NETs can expand more easily in the pulmonary alveoli, causing lung injury. Moreover, NETs and its associated molecules are able to directly induce epithelial and endothelial cell death. In this regard, massive NET formation has been reported in several pulmonary diseases, including asthma, chronic obstructive pulmonary disease, cystic fibrosis, respiratory syncytial virus bronchiolitis, influenza, bacterial pneumonia, and tuberculosis, among others. Thus, NET formation must be tightly regulated in order to avoid NET-mediated tissue damage. Recent development of therapies targeting NETs in pulmonary diseases includes DNA disintegration with recombinant human DNase, neutralization of NET proteins, with anti-histone antibodies and protease inhibitors. In this review, we summarize the recent knowledge on the pathophysiological role of NETs in pulmonary diseases as well as some experimental and clinical approaches to modulate their detrimental effects.
RESUMO
O treinamento aeróbio moderado tem sido reconhecido como um importante estimulador do sistema imune, no entanto o efeito deste na infecção bacteriana não tem sido extensivamente estudado. Nosso objetivo foi avaliar se o exercício aeróbio moderado prévio à infecção por S. pneumoniae influencia a resposta inflamatória pulmonar. Camundongos BALB/C foram divididos em 4 grupos: Controle (animais sedentários; não infectados); S. pneumoniae (animais sedentários e posteriormente infectados); Exercício (animais treinados; não infectados); Exercício + S. pneumoniae (animais treinados e posteriormente infectados). Os animais foram submetidos a um programa de treinamento físico aeróbio durante 4 semanas, e 72 horas após a última sessão de exercício, os animais receberam instilação nasal de S. pneumoniae (linhagem M10) e foram avaliados 12 horas (fase aguda) ou 10 dias (fase tardia) após a instilação. Na fase aguda, o grupo S. pneumoniae apresentou um aumento de: resistência e elastância do sistema respiratório, número total de células, neutrófilos, linfócitos e macrófagos no lavado broncoalveolar (BAL), células polimorfonucleares no parênquima pulmonar e TNF-alfa e IL-1beta no homogenato pulmonar. O exercício físico atenuou significantemente esses parâmentros. Além disso, o exercício físico resultou em aumento da expressão de enzimas antioxidantes no pulmão (CuZnSOD and MnSOD). Na fase tardia, o grupo Exercício + S. pneumoniae apresentou redução no número total de células e macrófagos no BAL, células polimorfonucleares no parênquima pulmonar e IL-6 no homogenato pulmonar comparado ao grupo S. pneumoniae. Nossos resultados sugerem um efeito protetor do exercício aeróbio moderado contra a infecção bacteriana pulmonar. Esse efeito é provavelmente secundário ao efeito do exercício no balanço oxidante-antioxidante.
Moderate aerobic exercise training has been recognized as an important stimulator of the immune system, but its effect on bacterial infection has not been extensively studied. Our aim was to determine whether moderate aerobic exercise training prior to S. pneumoniae infection influences pulmonary inflammatory responses. BALB/c mice were divided into 4 groups: Control (sedentary without infection); S. pneumoniae (sedentary with infection); Exercise (aerobic training without infection); Exercise + S. pneumoniae (aerobic training with infection). Animals underwent aerobic exercise training for 4 weeks. 72 h after last exercise training, animals received a challenge with S. pneumoniae (strain M10) and were evaluated either 12 h (acute phase) or 10 days (late phase) after instillation. In acute phase, S. pneumoniae group had an increase in respiratory system resistance and elastance; number of total cells, neutrophils, lymphocytes and macrophages in bronchoalveolar lavage fluid (BAL); polymorphonuclear cells in lung parenchyma; and levels of TNF-alfa and IL-1beta in lung homogenates. Exercise training significantly attenuated the increase in all of these parameters. In addition, exercise induced an increase in expression of antioxidant enzymes (CuZnSOD and MnSOD) in lungs. In late phase, Exercise + S. pneumoniae group exhibited a reduction in number of total cells and macrophages in BAL, in polymorphonuclear cells in lung parenchyma and in levels of IL-6 in lung homogenates compared to S. pneumoniae group. Our results suggest a protective effect of moderate exercise training against respiratory infection with S. pneumoniae. This effect is most likely secondary to an effect of exercise on oxidant-antioxidant balance.