RESUMEN
The thermally-dimorphic systemic fungal group includes several important human pathogens: Blastomyces dermatitides, Coccidioides immitis and C. posadasii, Histoplasma capsulatum, Paracoccidioides brasiliensis, P. lutzii, and Talaromyces (Penicillium) marneffei. They usually are geographically restricted and have natural habitats in soil or in plants, and when fungal propagules invade mammalian host by inhalation, they initiate an inflammatory reaction that can result in self-resolution of the infection or cause an acute or chronic disease. In the setting of the AIDS pandemic and the developments in modern medicine, such as immunosuppressive therapy in cancer surgery patients and in transplantation and autoimmune diseases, the incidence of endemic mycoses has progressively increased. Another important factor of the increased incidence of systemic mycoses in certain regions is the progressive devastation of tropical and subtropical forests. In this review, we focus on two of the most important systemic mycoses: paracoccidioidomycosis and histoplasmosis, and their major characteristics in epidemiology, clinical aspects and laboratorial diagnosis.
Asunto(s)
Antifúngicos/farmacología , Histoplasma/efectos de los fármacos , Histoplasmosis/diagnóstico , Histoplasmosis/tratamiento farmacológico , Paracoccidioides/efectos de los fármacos , Paracoccidioidomicosis/diagnóstico , Paracoccidioidomicosis/tratamiento farmacológico , Antifúngicos/química , Histoplasma/aislamiento & purificación , Histoplasmosis/epidemiología , Humanos , Pruebas de Sensibilidad Microbiana , Paracoccidioides/aislamiento & purificación , Paracoccidioidomicosis/epidemiologíaRESUMEN
Trichosporon species are rare etiologic agents of invasive fungal infection in solid organ transplant (SOT) recipients. We report 2 well-documented cases of Trichosporon inkin invasive infection in SOT patients. We also conducted a detailed literature review of Trichosporon species infections in this susceptible population. We gathered a total of 13 cases of Trichosporon species infections. Any type of organ transplantation can be complicated by Trichosporon infection. Bloodstream infections and disseminated infections were the most common clinical presentations. Liver recipients with bloodstream or disseminated infections had poor prognoses. Although the most common species was formerly called Trichosporon beigelii, this species name should no longer be used because of the changes in the taxonomy of this genus resulting from the advent of molecular approaches, which were also used to identify the strains isolated from our patients. Antifungal susceptibility testing highlights the possibility of multidrug resistance. Indeed, Trichosporon has to be considered in cases of breakthrough infection or treatment failure under echinocandins or amphotericin therapy. Voriconazole seems to be the best treatment option.
Asunto(s)
ADN de Hongos/análisis , Empiema/inmunología , Rechazo de Injerto/prevención & control , Trasplante de Corazón , Huésped Inmunocomprometido , Inmunosupresores/uso terapéutico , Enfermedades Pulmonares Fúngicas/inmunología , Trasplante de Pulmón , Mediastinitis/inmunología , Pericarditis/inmunología , Trichosporon/genética , Tricosporonosis/inmunología , Adulto , Antifúngicos/uso terapéutico , ADN Intergénico/análisis , ADN Ribosómico/análisis , Farmacorresistencia Fúngica , Empiema/diagnóstico , Empiema/tratamiento farmacológico , Humanos , Enfermedades Pulmonares Fúngicas/diagnóstico , Enfermedades Pulmonares Fúngicas/tratamiento farmacológico , Masculino , Mediastinitis/diagnóstico , Mediastinitis/tratamiento farmacológico , Pruebas de Sensibilidad Microbiana , Pericarditis/diagnóstico , Pericarditis/tratamiento farmacológico , Derrame Pleural/diagnóstico , Derrame Pleural/tratamiento farmacológico , Derrame Pleural/inmunología , Pirimidinas/uso terapéutico , Análisis de Secuencia de ADN , Triazoles/uso terapéutico , Tricosporonosis/diagnóstico , Tricosporonosis/tratamiento farmacológico , Voriconazol , Adulto JovenRESUMEN
OBJECTIVE: To determine the frequency of Candida spp., xerostomia, and salivary flow rate (SFR) in three different groups: patients with OLP (OLP group), patients with oral mucosal lesions other than OLP (non-OLP group), and subjects without oral mucosal lesions (control group). MATERIAL AND METHODS: Xerostomia as well as SFR was investigated in the three groups. Samples for isolation of Candida spp. were collected from OLP lesions (38 patients), non-OLP lesions (28 patients), and healthy subjects (32 subjects). RESULTS: There was no statistically significant difference regarding the frequency of xerostomia and hyposalivation among the three groups (P > 0.05). A higher prevalence for colonization by Candida spp. was found in the healthy subject as compared to that of patients with OLP (P = 0.03) and non-OLP (P = 0.02) groups. Low SFR was not a factor for colonization by Candida spp. CONCLUSIONS: Xerostomia and hyposalivation occur with similar frequency in subjects with and without oral lesions; also, the presence of oral lesions does not increase the susceptibility to colonization by Candida spp. It seems that any study implicating Candida spp. in the malignant transformation of oral lesions should be carried out mostly on a biochemical basis, that is, by testing the capability of Candida spp. to produce carcinogenic enzyme.
Asunto(s)
Candida/aislamiento & purificación , Candidiasis/epidemiología , Candidiasis/etiología , Liquen Plano Oral/complicaciones , Liquen Plano Oral/microbiología , Xerostomía/epidemiología , Xerostomía/etiología , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Adulto JovenRESUMEN
Trichosporon spp. have recently emerged as significant human pathogens. Identification of these species is important, both for epidemiological purposes and for therapeutic management, but conventional identification based on biochemical traits is hindered by the lack of updates to the species databases provided by the different commercial systems. In this study, 93 strains, or isolates, belonging to 16 Trichosporon species were subjected to both molecular identification using IGS1 gene sequencing and matrix-assisted laser desorption ionisation-time-of-flight (MALDI-TOF) analysis. Our results confirmed the limits of biochemical systems for identifying Trichosporon species, because only 27 (36%) of the isolates were correctly identified using them. Different protein extraction procedures were evaluated, revealing that incubation for 30 min with 70% formic acid yields the spectra with the highest scores. Among the six different reference spectra databases that were tested, a specific one composed of 18 reference strains plus seven clinical isolates allowed the correct identification of 67 of the 68 clinical isolates (98.5%). Although until recently it has been less widely applied to the basidiomycetous fungi, MALDI-TOF appears to be a valuable tool for identifying clinical Trichosporon isolates at the species level.
Asunto(s)
Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Trichosporon/química , Trichosporon/clasificación , Tricosporonosis/diagnóstico , Tricosporonosis/microbiología , Proteínas Fúngicas/química , Proteínas Fúngicas/aislamiento & purificación , Humanos , Sensibilidad y Especificidad , Manejo de Especímenes/métodos , Trichosporon/aislamiento & purificaciónRESUMEN
Current knowledge on the natural history of paracoccidioidomycosis states that the chronic form of the disease results from reactivation of quiescent foci established years or decades before during the primary lung infection. Once reactivated, the fungi can disseminate to virtually any organ or system. We present herein two chronic paracoccidioidomycosis patients with a single organ involvement that points to an alternative pathogenesis of the mycosis. These patients suggest that the chronic form may also arise from reactivation of foci not confined to the lungs, due to the early dissemination of yeast cells during the primary infection.
Asunto(s)
Enfermedades Intestinales/microbiología , Enfermedades Intestinales/patología , Paracoccidioidomicosis/patología , Colonoscopía , Femenino , Histocitoquímica , Humanos , Intestinos/patología , Pulmón/diagnóstico por imagen , Microscopía , Persona de Mediana Edad , Radiografía Torácica , Tomografía Computarizada por Rayos XRESUMEN
The present experiment aimed at demonstrating that the Greylag geese (Anser anser), commonly used for the production of foie gras, are able to develop spontaneous hyperphagia and subsequent liver steatosis under specific handling conditions and without overfeeding. One hundred and eighty male geese were used in this experiment. After a period of feed restriction, at the age of 19 wk, corn was provided ad libitum. From wk 21 to 23, the daylight duration was progressively reduced from 10 to 7 h and kept as such until the end of the experiment (wk 31). Thirty birds were slaughtered at wk 19, 23, 25, 27, 29, and 31. During the first 2 wk after corn delivery, the average consumption rose up to 600 g/bird/d and decreased slowly thereafter to reach 270 g at wk 31. The liver weight increased from 95 (wk 19) to 514 g (wk 31), and most of these changes were due to the increase in liver lipid content from 6 to 50% of liver weight. There was no mortality during the experimental period. Histological observations indicate that the accumulation of fat in the livers occurred through a large increase in the size of the hepatocytes without modification of the cell boundaries and without any sign of inflammation or degeneration. Our data clearly show that under specific management conditions of feeding and photoperiod, the geese are able to initiate spontaneous liver steatosis. These results demonstrate their natural ability to store fat in the liver without any visible sign of tissue alteration. However, the variability in the response remains very high (at wk 31, the CV in liver weight was 45%). Further research is needed to better understand the origin of this variability.
Asunto(s)
Crianza de Animales Domésticos , Anseriformes , Hígado Graso/veterinaria , Conducta Alimentaria , Enfermedades de las Aves de Corral/etiología , Alimentación Animal/análisis , Animales , Dieta/veterinaria , Hígado Graso/etiología , Privación de Alimentos , Metabolismo de los Lípidos , Lípidos/química , Hígado/anatomía & histología , Hígado/química , Hígado/crecimiento & desarrollo , Masculino , Tamaño de los Órganos , Zea maysRESUMEN
BACKGROUND: Infliximab and etarnecept are now widely used for treating severe psoriasis. However, these drugs, especially infliximab, increased the risk of tuberculosis reactivation. Surprisingly, epidemiological data suggest that the tuberculosis rate in patients taking infliximab in São Paulo State, Brazil, is similar to that of some developed, non-endemic countries. OBJECTIVE: The aim of this study was to better understand the effect of infliximab on Mycobacterium tuberculosis (Mtb) immune responses of psoriasis patients in an endemic setting (Brazil). METHODS: We evaluated the tuberculosis-specific immune responses of severe psoriasis patients and healthy individuals, both tuberculin skin test (TST) positive, in the presence/absence of infliximab. Patients had untreated severe psoriasis, no co-morbidities affecting the immune responses and a TST >10 mm. Healthy TST(+) (>10 mm) individuals were evaluated in parallel. PBMC cultures from both groups were stimulated with different Mycobacterium tuberculosis (Mtb) antigens (ESAT-6, 85B and Mtb lysate) and phytohemagglutinin, with or without infliximab (5 µg/mL). Parameters evaluated were TNF-α, IFN-γ and IL-10 secretion by ELISA, overnight IFN-γ ELISpot and lymphocyte proliferative response (LPR). RESULTS: Infliximab almost abolished TNF-α detection in PBMC supernatants of both groups. It also significantly reduced the LPR to phytohemagglutinin and the Mtb antigens as well as the IFN-γ levels secreted into day 5 supernatants in both groups. There was no concomitant exaggerated IL-10 secretion that could account for the decreases in these responses. ELISpot showed that, contrasting with the central-memory responses above, infliximab did not affect effector-memory INF-γ-releasing T-cell numbers. CONCLUSIONS: Infliximab affected some, but not all aspects of the in vitro antituberculosis immune responses tested. The preserved effector-memory responses, putatively related to exposure to environmental mycobacteria, may help to explain the lower than expected susceptibility to tuberculosis reactivation in our setting.
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Mycobacterium tuberculosis/inmunología , Psoriasis/tratamiento farmacológico , Adulto , Anticuerpos Monoclonales/inmunología , Ensayo de Inmunoadsorción Enzimática , Ensayo de Immunospot Ligado a Enzimas , Femenino , Humanos , Infliximab , Interferón gamma/sangre , Interleucina-10/sangre , Masculino , Psoriasis/inmunología , Estadísticas no Paramétricas , Prueba de Tuberculina , Factor de Necrosis Tumoral alfa/sangreRESUMEN
Leprosy still is an important public health problem in several parts of the world including Brazil. Unlike the diseases caused by other mycobacteria, the incidence and clinical presentation of leprosy seems little affected in immunosuppressed patients. We report the first case, to our knowledge, of a liver transplant patient who developed multi-bacillary leprosy. The patient presented with papules and infiltrated plaques with loss of sensation suggestive of leprosy 3.5 years after living-related liver transplantation for autoimmune hepatitis. A skin biopsy showing non-caseating macrophagic granulomas, neuritis, and intact acid-fast bacilli on Fite-Faraco stain, confirmed the diagnosis of borderline lepromatous leprosy. The donor of the liver did not show any evidence of leprosy. During follow-up, the patient presented 2 episodes of upgrading leprosy type I reactions, 1 mild before leprosy treatment, and 1 moderate 3 months after receiving standard multi-drug treatment (rifampicin, clofazimine, and dapsone). These reactions were accompanied by increase in liver function tests, especially of canalicular enzymes. This reaction occurred despite the patient's triple immunosuppression regimen. The moderate reaction was successfully treated with further immunosuppression (prednisone, 0.5 mg/kg). Currently, the patient is asymptomatic, off leprosy medication, with routine liver transplant follow-up. The dilemmas in diagnosis and management of such a case are discussed and the literature on leprosy in transplant recipients is reviewed.
Asunto(s)
Glucocorticoides/uso terapéutico , Leprostáticos/uso terapéutico , Lepra Multibacilar/diagnóstico , Lepra Multibacilar/tratamiento farmacológico , Trasplante de Hígado/efectos adversos , Mycobacterium leprae/efectos de los fármacos , Clofazimina/uso terapéutico , Quimioterapia Combinada , Humanos , Terapia de Inmunosupresión , Lepra Multibacilar/microbiología , Lepra Multibacilar/patología , Masculino , Persona de Mediana Edad , Mycobacterium leprae/aislamiento & purificación , Prednisona/uso terapéutico , Piel/microbiología , Piel/patología , Resultado del TratamientoRESUMEN
The immunopathogenesis of chronic hepatitis C virus (HCV) infection is a matter of great controversy and has been suggested to involve a complex balance between cytokines with pro and anti-inflammatory activity. We investigated the expression of inflammatory cells and cytokines in the liver and serum of 51 chronically HCV infected patients and compared them to data from two sets of normal controls: 51 healthy blood donors and 33 liver biopsies of healthy liver donors. We also assessed the relationship between selected cytokines and cell populations in hepatic compartments and the disease stage. Compared with controls, hepatitis C patients had a greater expression of portal TNF-alpha, TGF-beta and CD4(+) and acinar IFN-gamma, TNF-alpha, IL-1beta and IL-4, as well as a higher serum concentration of IL-2, IL-10 and TGF-beta. Significant positive correlations were found between portal CD4+ and TNF-alpha, portal CD8(+) and TGF-beta, portal CD45(+)RO and TNF-alpha, acinar CD45(+)RO and IFN-gamma and acinar CD57(+) and TGF-beta. In conclusion, we have shown that (i) in this sample of predominantly mild disease, the immune response was associated with a pro-inflammatory response pattern, (ii) CD4(+) T-lymphocytes played a major role in orchestrating the immune response and (iii) these events primarily took place in the portal space.
Asunto(s)
Citocinas/inmunología , Hepatitis C Crónica/inmunología , Adolescente , Adulto , Estudios de Casos y Controles , Femenino , Hepatitis C Crónica/patología , Humanos , Inmunidad Celular , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Linfocitos T/inmunología , Adulto JovenRESUMEN
With the extraordinary progress of mitochondrial science and cell biology, novel biochemical pathways have emerged as strategic points of bioenergetic regulation and control. They include mitochondrial fusion, fission and organellar motility along microtubules and microfilaments (mitochondrial dynamics), mitochondrial turnover (biogenesis and degradation), and mitochondrial phospholipids synthesis. Yet, much is still unknown about the mutual interaction between mitochondrial energy state, biogenesis, dynamics and degradation. Meanwhile, clinical research into metabolic abnormalities in tumors as diverse as renal carcinoma, glioblastomas, paragangliomas or skin leiomyomata, has designated new genes, oncogenes and oncometabolites involved in the regulation of cellular and mitochondrial energy production. Furthermore, the examination of rare neurological diseases such as Charcot-Marie Tooth type 2a, Autosomal Dominant Optic Atrophy, Lethal Defect of Mitochondrial and Peroxisomal Fission, or Spastic Paraplegia suggested involvement of MFN2, OPA1/3, DRP1 or Paraplegin, in the auxiliary control of mitochondrial energy production. Lastly, advances in the understanding of mitochondrial apoptosis have suggested a supplementary role for Bcl2 or Bax in the regulation of mitochondrial respiration and dynamics, which has fostered the investigation of alternative mechanisms of energy regulation. In this review, we discuss the regulatory mechanisms of cellular and mitochondrial energy production, and we emphasize the importance of the study of rare neurological diseases in addition to more common disorders such as cancer, for the fundamental understanding of cellular and mitochondrial energy production.
Asunto(s)
Mitocondrias/metabolismo , Adenosina Trifosfato/biosíntesis , Animales , Núcleo Celular/metabolismo , Metabolismo Energético , Homeostasis , Humanos , Modelos Biológicos , Neoplasias/metabolismo , Enfermedades del Sistema Nervioso/metabolismo , Orgánulos/metabolismo , Fosforilación Oxidativa , Transducción de SeñalRESUMEN
The immunopathogenesis of chronic hepatitis C virus (HCV) infection is a matter of great controversy and has been suggested to involve a complex balance between cytokines with pro and anti-inflammatory activity. We investigated the expression of inflammatory cells and cytokines in the liver and serum of 51 chronically HCV infected patients and compared them to data from two sets of normal controls: 51 healthy blood donors and 33 liver biopsies of healthy liver donors. We also assessed the relationship between selected cytokines and cell populations in hepatic compartments and the disease stage. Compared with controls, hepatitis C patients had a greater expression of portal TNF-á, TGF-â and CD4+ and acinar IFN-ã, TNF-á, IL-1â and IL-4, as well as a higher serum concentration of IL-2, IL-10 and TGF-â. Significant positive correlations were found between portal CD4+ and TNF-á, portal CD8+ and TGF-â, portal CD45+RO and TNF-á, acinar CD45+RO and IFN-ã and acinar CD57+ and TGF-â. In conclusion, we have shown that (i) in this sample of predominantly mild disease, the immune response was associated with a pro-inflammatory response pattern, (ii) CD4+ T-lymphocytes played a major role in orchestrating the immune response and (iii) these events primarily took place in the portal space.
Asunto(s)
Adolescente , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Citocinas/inmunología , Hepatitis C Crónica/inmunología , Estudios de Casos y Controles , Hepatitis C Crónica/patología , Inmunidad Celular , Inmunohistoquímica , Índice de Severidad de la Enfermedad , Linfocitos T/inmunología , Adulto JovenRESUMEN
Little is known on the metabolic profile of lung tumors and the reminiscence of embryonic features. Herein, we determined the bioenergetic profiles of human fibroblasts taken from lung epidermoid carcinoma (HLF-a) and fetal lung (MRC5). We also analysed human lung tumors and their surrounding healthy tissue from four patients with adenocarcinoma. On these different models, we measured functional parameters (cell growth rates in oxidative and glycolytic media, respiration, ATP synthesis and PDH activity) as well as compositional features (expression level of various energy proteins and upstream transcription factors). The results demonstrate that both the lung fetal and cancer cell lines produced their ATP predominantly by glycolysis, while oxidative phosphorylation was only capable of poor ATP delivery. This was explained by a decreased mitochondrial biogenesis caused by a lowered expression of PGC1alpha (as shown by RT-PCR and Western blot) and mtTFA. Consequently, the relative expression of glycolytic versus OXPHOS markers was high in these cells. Moreover, the re-activation of mitochondrial biogenesis with resveratrol induced cell death specifically in cancer cells. A consistent reduction of mitochondrial biogenesis and the subsequent alteration of respiratory capacity was also observed in lung tumors, associated with a lower expression level of bcl2. Our data give a better characterization of lung cancer cells' metabolic alterations which are essential for growth and survival. They designate mitochondrial biogenesis as a possible target for anti-cancer therapy.
Asunto(s)
Adenocarcinoma/metabolismo , Carcinoma de Células Escamosas/metabolismo , Proteínas de Unión al ADN/biosíntesis , Proteínas de Choque Térmico/biosíntesis , Neoplasias Pulmonares/metabolismo , Mitocondrias/metabolismo , Proteínas Mitocondriales/biosíntesis , Proteínas Proto-Oncogénicas c-bcl-2/biosíntesis , Factores de Transcripción/biosíntesis , Adenocarcinoma/genética , Adenocarcinoma/ultraestructura , Adenosina Trifosfato/biosíntesis , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/ultraestructura , Procesos de Crecimiento Celular , Línea Celular , Respiración de la Célula , Proteínas de Unión al ADN/genética , Feto , Regulación Neoplásica de la Expresión Génica , Glucólisis , Proteínas de Choque Térmico/genética , Humanos , Pulmón , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/ultraestructura , Mitocondrias/genética , Proteínas Mitocondriales/genética , Fosforilación Oxidativa , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/genética , Piruvato Deshidrogenasa Quinasa Acetil-Transferidora , Factores de Transcripción/genéticaRESUMEN
The neurotoxic compound methylmercury (MeHg) is a commonly encountered pollutant in the environment, and constitutes a hazard for human health through fish eating. To study the impact of MeHg on mitochondrial structure and function, we contaminated the model fish species Danio rerio with food containing 13 microg of MeHg per gram, an environmentally relevant dose. Mitochondria from contaminated zebrafish muscles presented structural abnormalities under electron microscopy observation. In permeabilized muscle fibers, we observed, a strong inhibition of both state 3 mitochondrial respiration and functionally isolated maximal cytochrome c oxidase (COX) activity after 49 days of MeHg exposure. However, the state 4 respiratory rate remained essentially unchanged. This suggested a defect at the level of ATP synthesis. Accordingly, we measured a dramatic decrease in the rate of ATP release by skinned muscle fibers using either pyruvate and malate or succinate as respiratory substrates. However, the amount and the assembly of the ATP synthase were identical in both control and contaminated muscle mitochondrial fractions. This suggests that MeHg induced a decoupling of mitochondrial oxidative phosphorylation in the skeletal muscle of zebrafish. Western blot analysis showed a 30% decrease of COX subunit IV levels, a 50% increase of ATP synthase subunit alpha, and a 40% increase of the succinate dehydrogenase Fe/S protein subunit in the contaminated muscles. This was confirmed by the analysis of gene expression levels, using RT-PCR. Our study provides a basis for further analysis of the deleterious effect of MeHg on fish health via mitochondrial impairment.
Asunto(s)
Compuestos de Metilmercurio/toxicidad , Mitocondrias/efectos de los fármacos , Músculo Esquelético/efectos de los fármacos , Pez Cebra/metabolismo , Adenosina Trifosfato/biosíntesis , Adenosina Trifosfato/metabolismo , Animales , Respiración de la Célula/efectos de los fármacos , Transporte de Electrón/efectos de los fármacos , Complejo IV de Transporte de Electrones/metabolismo , Metabolismo Energético/efectos de los fármacos , Expresión Génica/efectos de los fármacos , Masculino , Microscopía Electrónica de Transmisión , Mitocondrias/enzimología , Mitocondrias/metabolismo , Mitocondrias/ultraestructura , ATPasas de Translocación de Protón Mitocondriales/biosíntesis , ATPasas de Translocación de Protón Mitocondriales/genética , Músculo Esquelético/enzimología , Músculo Esquelético/metabolismo , NADH Deshidrogenasa/biosíntesis , NADH Deshidrogenasa/genética , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
Activity defects in respiratory chain complexes are responsible for a large variety of pathological situations, including neuromuscular diseases and multisystemic disorders. Their impact on energy production is highly variable and disproportional. The same biochemical or genetic defect can lead to large differences in clinical symptoms and severity between tissues and patients, making the pathophysiological analysis of mitochondrial diseases difficult. The existence of compensatory mechanisms operating at the level of the respiratory chain might be an explanation for the biochemical complexity observed for respiratory defects. Here, we analyzed the role of cytochrome c and coenzyme Q in the attenuation of complex III and complex IV pharmacological inhibition on the respiratory flux. Spectrophotometry, HPLC-EC, polarography and enzymology permitted the calculation of molar ratios between respiratory chain components, giving values of 0.8:61:3:12:6.8 in muscle and 1:131:3:9:6.5 in liver, for CII:CoQ:CIII:Cyt c:CIV. The results demonstrate the dynamic functional compartmentalization of respiratory chain substrates, with the existence of a substrate pool that can be recruited to maintain energy production at normal levels when respiratory chain complexes are inhibited. The size of this reserve was different between muscle and liver, and in proportion to the magnitude of attenuation of each respiratory defect. Such functional compartmentalization could result from the recently observed physical compartmentalization of respiratory chain substrates. The dynamic nature of the mitochondrial network may modulate this compartmentalization and could play a new role in the control of mitochondrial respiration as well as apoptosis.
Asunto(s)
Citocromos c/fisiología , Transporte de Electrón/fisiología , Enfermedades Mitocondriales/tratamiento farmacológico , Enfermedades Mitocondriales/fisiopatología , Ubiquinona/fisiología , Animales , Complejo III de Transporte de Electrones/antagonistas & inhibidores , Complejo IV de Transporte de Electrones/antagonistas & inhibidores , Complejo IV de Transporte de Electrones/metabolismo , Masculino , Metacrilatos/farmacología , Mitocondrias Hepáticas/metabolismo , Mitocondrias Musculares/metabolismo , Consumo de Oxígeno , Cianuro de Potasio/farmacología , Ratas , Ratas Wistar , Tiazoles/farmacologíaRESUMEN
Paracoccidioidomycosis is caused by Paracoccidioides brasiliensis, which although not formally considered an intracellular pathogen, can be internalized by epithelial cells in vitro and in vivo. The mechanisms used by P. brasiliensis to adhere to and invade non-professional phagocytes have not been identified. The signal-transduction networks, involving protein tyrosine kinase (PTK) and protein phosphatase activities, can modulate crucial events during fungal infections. In this study, the involvement of PTK has been investigated in P. brasiliensis adherence and invasion in mammalian epithelial cells. A significant inhibition of the fungal invasion occurred after the pre-treatment of the epithelial cells with genistein, a specific tyrosine kinase inhibitor, indicating that the tyrosine kinase pathway is involved in P. brasiliensis internalization. In contrast, when the fungus was treated, a slight (not significant) inhibition of PTK was observed, suggesting that PTK might not be the fungus' transduction signal pathway during the invasion process of epithelial cells. An intense PTK immunofluorescence labeling was observed in the periphery of the P. brasiliensis infected cells, little PTK labeling was found in both uninfected cells and yeast cells, at later infection times (8 and 24 h). Moreover, when the epithelial cells were treated with genistein and infected with P. brasiliensis, no labeling was observed, suggesting the importance of the PTK in the infectious process. These results suggest that PTK pathway participates in the transduction signal during the initial events of the adhesion and invasion processes of P. brasiliensis to mammalian epithelial cells.
Asunto(s)
Adhesión Bacteriana/efectos de los fármacos , Endocitosis/efectos de los fármacos , Células Epiteliales/efectos de los fármacos , Genisteína/farmacología , Paracoccidioides/efectos de los fármacos , Línea Celular Tumoral , Inhibidores Enzimáticos/farmacología , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Humanos , Microscopía Confocal , Paracoccidioides/crecimiento & desarrollo , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Proteínas Tirosina Quinasas/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Two case reports of patients with human immunodeficiency virus type 1 (HIV-1) infection who developed leprosy are presented. Both developed type 1 leprosy reactions in the absence of antiretroviral therapy. Reactions have been described for a number of HIV-1- and Mycobacterium leprae-coinfected patients and have been considered to be part of an immune reconstitution inflammatory syndrome (IRIS) since the reactions were usually linked to the administration of highly active antiretroviral therapy. The reports of our two patients suggest that the type 1 reactions in patients with leprosy and HIV may not always be an IRIS manifestation but may be akin to the classical reactional state described for the natural course of leprosy infection, which occurs in leprosy patients due to the fluctuations of the antimycobacterial immune response, whether they are coinfected with HIV or not.
Asunto(s)
Infecciones por VIH/complicaciones , VIH-1 , Lepra/inmunología , Adulto , Fármacos Anti-VIH/uso terapéutico , Brasil , Femenino , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/inmunología , Histocitoquímica , Humanos , Leprostáticos/uso terapéutico , Lepra/complicaciones , Lepra/microbiología , Lepra/patología , Masculino , Embarazo , Complicaciones Infecciosas del Embarazo/tratamiento farmacológico , Complicaciones Infecciosas del Embarazo/inmunología , Piel/patologíaRESUMEN
To investigate the physiological diversity in the regulation and control of mitochondrial oxidative phosphorylation, we determined the composition and functional features of the respiratory chain in muscle, heart, liver, kidney, and brain. First, we observed important variations in mitochondrial content and infrastructure via electron micrographs of the different tissue sections. Analyses of respiratory chain enzyme content by Western blot also showed large differences between tissues, in good correlation with the expression level of mitochondrial transcription factor A and the activity of citrate synthase. On the isolated mitochondria, we observed a conserved molar ratio between the respiratory chain complexes and a variable stoichiometry for coenzyme Q and cytochrome c, with typical values of [1-1.5]:[30-135]:[3]:[9-35]:[6.5-7.5] for complex II:coenzyme Q:complex III:cytochrome c:complex IV in the different tissues. The functional analysis revealed important differences in maximal velocities of respiratory chain complexes, with higher values in heart. However, calculation of the catalytic constants showed that brain contained the more active enzyme complexes. Hence, our study demonstrates that, in tissues, oxidative phosphorylation capacity is highly variable and diverse, as determined by different combinations of 1) the mitochondrial content, 2) the amount of respiratory chain complexes, and 3) their intrinsic activity. In all tissues, there was a large excess of enzyme capacity and intermediate substrate concentration, compared with what is required for state 3 respiration. To conclude, we submitted our data to a principal component analysis that revealed three groups of tissues: muscle and heart, brain, and liver and kidney.
Asunto(s)
Encéfalo/metabolismo , Riñón/metabolismo , Hígado/metabolismo , Mitocondrias , Músculos/metabolismo , Miocardio/metabolismo , Fosforilación Oxidativa , Animales , Encéfalo/citología , Citrato (si)-Sintasa/metabolismo , Citocromos/metabolismo , Transporte de Electrón/fisiología , Complejo I de Transporte de Electrón/fisiología , Complejo II de Transporte de Electrones/fisiología , Complejo III de Transporte de Electrones/fisiología , Complejo IV de Transporte de Electrones/fisiología , Humanos , Riñón/citología , Hígado/citología , Masculino , Mitocondrias/metabolismo , Mitocondrias/ultraestructura , Proteínas Mitocondriales/metabolismo , Músculos/citología , Miocardio/citología , Ratas , Ratas WistarRESUMEN
Sa and the Sa/So ratio are very sensitive biomarkers of exposure to fumonisins in several species. We previously demonstrated that increases in Sa and in the Sa/So ratio in serum were less pronounced when ducks ingested fumonisins for more than 7 weeks than when animals were exposed for only 1-2 weeks [S.T. Tran, D. Tardieu, A. Auvergne, J.D. Bailly, R. Babilé, S. Durand, G. Benard, P. Guerre, Serum sphinganine and the sphinganine to sphingosine ratio as biomarker of dietary fumonisins during chronic exposure in ducks, Chem. Biol. Interact., in press]. The aim of this study was to investigate the kinetics of Sa and of the Sa/So in both liver and kidney of ducks that have been previously tested for Sa and the Sa/So ratio in serum. Analysis were performed on treatment days 0, 7, 14, 28 and 77 in five groups of ducks fed fumonisins obtained from an extract of Fusarium verticillioides culture material by daily gavage to obtain an exposure equal to 0, 2, 8, 32 and 128 mg FB1/kg feed. Sa and the Sa/So ratio in tissues were then correlated with Sa and the Sa/So ratio previously obtained in serum. The amounts on sphinganine 1-phosphate (Sa1P) and sphingosine1-phosphate (So1P) in the liver were also investigated. On day 7 of treatment, 2mg/kg FB1 in the feed were sufficient to increase Sa and the Sa/So ratio in liver (by 165 and 148%, respectively) and kidney (by 193 and 104%, respectively). At a rate of 128 mg/kg FB1 in the feed, a very high increase in Sa concentration was observed in both liver and kidney without mortality and/or signs of necrosis (respective increase of 2034 and 3768%). Although the precise mechanism of the resistance of ducks to fumonisin-induced hepatotoxicity is still uncertain, it might be linked to the rate at which the sphingoid bases sphinganine and sphingosine are converted to their 1-phosphate or other metabolite and eliminated from target tissues.
Asunto(s)
Carcinógenos Ambientales/toxicidad , Fumonisinas/toxicidad , Riñón/efectos de los fármacos , Hígado/efectos de los fármacos , Micotoxinas , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Administración Oral , Animales , Biomarcadores/sangre , Carcinógenos Ambientales/farmacocinética , Dieta , Relación Dosis-Respuesta a Droga , Patos , Fumonisinas/farmacocinética , Riñón/metabolismo , Riñón/patología , Hígado/metabolismo , Hígado/patología , Lisofosfolípidos/metabolismo , Tamaño de los Órganos/efectos de los fármacos , Pruebas de Toxicidad/métodosRESUMEN
Sphinganine concentration (Sa) and sphinganine to sphingosine ratio (Sa/So) are sensitive biomarkers of fumonisin B1 (FB1) exposure in animals and have been proposed to reveal FB1 exposure in humans. They correlate with liver and kidney toxicity and often precede signs of toxicity. However, the use of Sa and Sa/So is confusing during chronic exposure. Indeed, some authors report altered sphingolipids metabolism, whereas others fail to demonstrate significant effect. The aim of this study was to investigate the kinetics of Sa and Sa/So in the serum of ducks over a 77-day exposure to 0, 2, 8, 32 and 128 mg FB1/kg feeds. Serum biochemistry was also investigated to reveal hepatotoxicity. The results obtained indicate that the kinetics of sphingolipids and serum biochemistry are closely linked with the duration of the exposure. After a strong and rapid increase Sa and Sa/So decrease then stabilize. The lowest investigated dose able to determine a detectable effect is 2 mg/kg feeds, the Sa/So ratio being the most sensitive biomarker of FB1 exposure.
Asunto(s)
Carcinógenos Ambientales/farmacocinética , Fumonisinas/farmacocinética , Micotoxinas , Esfingosina/análogos & derivados , Esfingosina/sangre , Animales , Biomarcadores/sangre , Carcinógenos Ambientales/toxicidad , Pruebas de Química Clínica , Dieta , Relación Dosis-Respuesta a Droga , Patos , Fumonisinas/toxicidad , Hígado/efectos de los fármacos , Hígado/patología , Pruebas de Función Hepática , Tamaño de los Órganos/efectos de los fármacos , Pruebas de Toxicidad/métodosRESUMEN
Intracellular amyloid beta-peptide (A beta) accumulation is considered to be a key pathogenic factor in sporadic Alzheimer's disease (AD), but the mechanisms by which it triggers neuronal dysfunction remain unclear. We hypothesized that gradual mitochondrial dysfunction could play a central role in both initiation and progression of sporadic AD. Thus, we analyzed changes in mitochondrial structure and function following direct exposure to increasing concentrations of A beta(1--42) and A beta(25--35) in order to look more closely at the relationships between mitochondrial membrane viscosity, ATP synthesis, ROS production, and cytochrome c release. Our results show the accumulation of monomeric A beta within rat brain and muscle mitochondria. Subsequently, we observed four different and additive modes of action of A beta, which were concentration dependent: (i) an increase in mitochondrial membrane viscosity with a concomitant decrease in ATP/O, (ii) respiratory chain complexes inhibition, (iii) a potentialization of ROS production, and (iv) cytochrome c release.