RESUMO
BACKGROUND: Aldehyde dehydrogenases (ALDHs) are key players in cell survival, protection, and differentiation via the metabolism and detoxification of aldehydes. ALDH activity is also a marker of stem cells. The skeletal muscle contains populations of ALDH-positive cells amenable to use in cell therapy, whose distribution, persistence in aging, and modifications in myopathic context have not been investigated yet. METHODS: The Aldefluor® (ALDEF) reagent was used to assess the ALDH activity of muscle cell populations, whose phenotypic characterizations were deepened by flow cytometry. The nature of ALDH isoenzymes expressed by the muscle cell populations was identified in complementary ways by flow cytometry, immunohistology, and real-time PCR ex vivo and in vitro. These populations were compared in healthy, aging, or Duchenne muscular dystrophy (DMD) patients, healthy non-human primates, and Golden Retriever dogs (healthy vs. muscular dystrophic model, Golden retriever muscular dystrophy [GRMD]). RESULTS: ALDEF+ cells persisted through muscle aging in humans and were equally represented in several anatomical localizations in healthy non-human primates. ALDEF+ cells were increased in dystrophic individuals in humans (nine patients with DMD vs. five controls: 14.9 ± 1.63% vs. 3.6 ± 0.39%, P = 0.0002) and dogs (three GRMD dogs vs. three controls: 10.9 ± 2.54% vs. 3.7 ± 0.45%, P = 0.049). In DMD patients, such increase was due to the adipogenic ALDEF+ /CD34+ populations (11.74 ± 1.5 vs. 2.8 ± 0.4, P = 0.0003), while in GRMD dogs, it was due to the myogenic ALDEF+ /CD34- cells (3.6 ± 0.6% vs. 1.03 ± 0.23%, P = 0.0165). Phenotypic characterization associated the ALDEF+ /CD34- cells with CD9, CD36, CD49a, CD49c, CD49f, CD106, CD146, and CD184, some being associated with myogenic capacities. Cytological and histological analyses distinguished several ALDH isoenzymes (ALDH1A1, 1A2, 1A3, 1B1, 1L1, 2, 3A1, 3A2, 3B1, 3B2, 4A1, 7A1, 8A1, and 9A1) expressed by different cell populations in the skeletal muscle tissue belonging to multinucleated fibres, or myogenic, endothelial, interstitial, and neural lineages, designing them as potential new markers of cell type or of metabolic activity. Important modifications were noted in isoenzyme expression between healthy and DMD muscle tissues. The level of gene expression of some isoenzymes (ALDH1A1, 1A3, 1B1, 2, 3A2, 7A1, 8A1, and 9A1) suggested their specific involvement in muscle stability or regeneration in situ or in vitro. CONCLUSIONS: This study unveils the importance of the ALDH family of isoenzymes in the skeletal muscle physiology and homeostasis, suggesting their roles in tissue remodelling in the context of muscular dystrophies.
Assuntos
Aldeído Desidrogenase/metabolismo , Envelhecimento Saudável/fisiologia , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/fisiopatologia , Homeostase , HumanosRESUMO
Myasthenia gravis (MG) is a rare autoimmune disease mediated by pathogenic antibodies (Ab) directed against components of the neuromuscular junction (NMJ), mainly the acetylcholine receptor (AChR). The etiological mechanisms are not totally elucidated, but they include a combination of genetic predisposition, triggering event(s), and hormonal components. MG disease is associated with defective immune regulation, chronic cell activation, inflammation, and the thymus is frequently abnormal. MG is characterized by muscle fatigability that is very invalidating and can be life-threatening when respiratory muscles are affected. MG is not cured, and symptomatic treatments with acetylcholinesterase inhibitors and immunosuppressors are life-long medications associated with severe side effects (especially glucocorticoids). While the muscle is the ultimate target of the autoimmune attack, its place and role are not thoroughly described, and this mini-review will focus on the cascade of pathophysiologic mechanisms taking place at the NMJ and its consequences on the muscle biology, function, and regeneration in myasthenic patients, at the histological, cellular, and molecular levels. The fine structure of the synaptic cleft is damaged by the Ab binding that is coupled to focal complement-dependent lysis in the case of MG with anti-AChR antibodies. Cellular and molecular reactions taking place in the muscle involve several cell types as well as soluble factors. Finally, the regenerative capacities of the MG muscle tissue may be altered. Altogether, the studies reported in this review demonstrate that the muscle is not a passive target in MG, but interacts dynamically with its environment in several ways, activating mechanisms of compensation that limit the pathogenic mechanisms of the autoantibodies.
RESUMO
INTRODUCCIÓN: La comprensión del comportamiento de la respuesta humoral en COVID-19 continúa siendo un desafío para la producción de vacunas que proporcionen inmunidad más duradera. OBJETIVO: Describir la respuesta humoral natural inducida por SARS- CoV-2 en personal de salud con base en el perfil epidemiológico y clínico. MATERIALES Y MÉTODOS: Estudio transversal en personal de salud de hospitales públicos de referencia del Departamento de Alto Paraná, Paraguay. Se incluyeron 962 participantes, mediante muestreo no probabilístico de tipo consecutivo, aplicación de cuestionario y toma de muestras sanguíneas. Se buscaron anticuerpos por ensayo inmunocromatográfico para detección de IgM e IgG contra SARS- CoV-2 y por el método ELISA de captura de IgG específicos contra la proteína spike (SARS-CoV-2) y se evaluaron factores asociados a la seropositividad. RESULTADOS: La seroprevalencia global fue 36,5% (IC 95%: 33,4 - 39,5); 59,3% (n: 571) de los encuestados refirió haber tenido síntomas compatibles al COVID-19 entre el inicio de la pandemia y la fecha de toma de muestra, de estos 44% (n: 251) resultó seropositivo; 10,4% (n: 100) manifestó no haber tenido síntomas en el periodo estudiado, pero tuvo un resultado positivo. Los factores asociados a la seropositividad fueron: presencia de síntomas (p 90 días). CONCLUSIONES: Las características clínicas fueron mayormente asociadas con la seropositividad y la seropreva- lencia en los sintomáticos varió de acuerdo con el tiempo transcurrido desde el inicio de los síntomas y la serología.
BACKGROUND: Understanding the behavior of humoral response in COVID-19 continues to be a challenge to produce vaccines that provide long-lasting immunity. AIM: To describe the natural humoral response induced by SARS-CoV-2 among healthcare workers based on epidemiological and clinical profiles. METHODS: Cross-sectional study in healthcare workers from public hospitals in the Department of Alto Paraná, Paraguay, 962 participants were recruited through consecutive sampling, using a questionnaire and blood sampling. Antibodies were determined by immunochromatography assay for detection of IgM and IgG and by SARS-CoV-2 IgG anti-spike capture ELISA method and factors associated with seropositivity were evaluated. RESULTS: The overall seropositivity was 36.5% (95% CI: 33.4 - 39.5); 59.3% (n: 571) of respondents reported symptoms compatible with COVID-19 since the start of the pandemic and the date of blood draw, 44% (n: 251) of them tested positive; 10.4% (n: 100) who reported no history of symptoms tested positive. The factors associated with seropositivity were the presence of symptoms (p 90 days). CONCLUSIONS: Clinical characteristics were mostly associated with seropositivity and sero prevalence in symptomatic participants varied according to the time elapsed from the onset of symptoms to serology.