Autores: Francisco R. Klein,  Julia Klein, Diego Otalora Lozano, Carlos Vigliano.

Abstract: We present the case of a lung transplant candidate under veno-venous membrane oxygenation assistance (VV ECMO) whose diagnosis of emphysema of undetermined etiology was redefined as Langerhans cell histiocytosis (LCH) due to a scalp skin biopsy performed years after the beginning of his respiratory symptoms. A 20-year-old patient started three years before his admission with progressive dyspnea leading to a diagnosis of bullous emphysema of undetermined cause, which evolved into respiratory failure and evaluation for bilateral lung transplant. Three years later, he developed bilateral pneumonia requiring mechanical ventilation. When refractory hypoxemia ensued, he had to be placed on VV ECMO. Under these conditions, he was transferred to our center and listed for a bilateral pulmonary transplantation. Forty-eight hours after admission, and due to intense polyuria, central diabetes insipidus was diagnosed. In this clinical context, the presence of cutaneous lesions on the scalp was reconsidered and biopsied under the presumption of possible LCH, with pathology analysis confirming the diagnosis. He continued to be assisted with VV ECMO for 66 more days as a bridge to transplantation, developing multi-organ failure and passing away before a donor organ was available. The diagnosis of LCH should be considered in any adult patient with bullous emphysema of undetermined cause. Given the possibility of early therapeutic interventions, the search for its clinical associations (e.g., diabetes insipidus and/or skin lesions) should be a systematic part of the etiologic workup. The availability of skin specimens to reach a diagnosis makes its thorough search an important part of the diagnostic approach.

Disponible en: Cureus

Autores: Franco Appiani, Carlos Santiago Claverie , Francisco R Klein.

Abstract: Introduction Posterior reversible leukoencephalopathy syndrome (PRES) is a clinical-radiological condition characterized by reversible subcortical vasogenic cerebral edema of acute or subacute onset in circumstances that disrupt capillary permeability, unfrequently accompanied by cytotoxic and/or hemorrhagic lesions. We describe a case series of PRES with hemorrhagic features. Subjects and methods Electronic medical records of hospitalized patients diagnosed with PRES from January 2009 to December 2021 were collected. Demographic data, medical history, clinical presentation, and outcome were recorded. Variables were compared between patients with and without hemorrhagic features using the Wilcoxon-Mann-Whitney test with a statistical significance level of p<0.05. Results Over a 12-year period, 33 patients were diagnosed with PRES, of whom 10 had hemorrhagic features: seven cortical microbleeds, two intraparenchymal hematomas, and one subarachnoid hemorrhage. Half of the patients were women, with a median age of 45.8 years (interquartile range (IQR) 21.8), and were admitted for non-neurological reasons. The sample included nine transplant recipients (six solid organa, three bone marrowa), with four patients in the immediate post-transplant period. PRES occurred in the context of infections and blood pressure fluctuations under cytotoxic drugs, such as immunosuppressants. Seventy percent showed improvement/resolution on neuroimaging at a median of 70 days (IQR 62.9). The three major hemorrhages occurred in the context of thrombocytopenia. The recorded in-hospital mortality was 10%. When compared to PRES without hemorrhagic features, patients with hemorrhagic features had a lower use of corticosteroids (50% vs. 78.8%; p=0.02) and a higher presence of restrictive lesions on neuroimaging (60% vs. 17%; p=0.04), with no differences in the other analyzed variables. Conclusion Patients with PRES and hemorrhagic features had a lower use of corticosteroids and a higher presence of restrictive lesions on neuroimaging. Further studies are needed to better understand the clinical implications and management of PRES with hemorrhagic manifestations.

Disponible en: Pub Med

Cromatografía de intercambio iónico como método simple y escalable para aislar pequeñas vesículas extracelulares biológicamente activas de medios condicionados.

(Ion exchange chromatography as a simple and scalable method to isolate biologically active small extracellular vesicles from conditioned media)

IMETTYB

Autores: Ricardo Malvicini, Diego Santa-Cruz, Anna Maria Tolomeo, Maurizio Muraca, Gustavo Yannarelli, Natalia Pacienza

Resumen:En los últimos años, las vesículas extracelulares (VE) se han vuelto de gran interés debido a su potencial como biomarcadores, sistemas de administración de fármacos y, en particular, agentes terapéuticos. Sin embargo, no hay consenso sobre cuál es la mejor manera de aislar estos VEs. La elección del método de aislamiento depende del material de partida (es decir, medios de cultivo condicionados, orina, suero, etc.) y sus aplicaciones posteriores. Aunque existen numerosos métodos para aislar vesículas extracelulares, pocos son compatibles con aplicaciones clínicas porque no son escalables. En el presente trabajo, configuramos un protocolo para aislar vesículas extracelulares de medios condicionados mediante cromatografía de intercambio iónico, un método simple, rápido y escalable, adecuado para la producción clínica. Realizamos el aislamiento utilizando una resina de intercambio aniónico (Q sefarosa) y eluimos las VEs utilizando NaCl 500 mM. Caracterizamos el perfil de elución midiendo la concentración de proteínas y lípidos, y CD63 mediante ELISA. Además, inmunofenotipamos todas las fracciones eluidas, evaluamos la presencia de TSG101, calnexina y citocromo C mediante Western Blot, analizamos el tamaño y la distribución de las nanopartículas mediante tRPS y la morfología mediante TEM. Finalmente, evaluamos la actividad inmunomoduladora in vitro. Descubrimos que la mayoría de las vesículas extracelulares se eluyen y concentran en una fracción de pico único, con un tamaño medio de partícula de <150 nm y expresión de los marcadores CD9, CD63, CD81 y TSG101. Además, las VEs de la fracción 4 ejercieron una actividad antiinflamatoria en los macrófagos estimulados por LPS. En resumen, configuramos un método cromatográfico, escalable y clínicamente compatible para aislar y concentrar vesículas extracelulares pequeñas a partir de medios condicionados, que preserva la actividad biológica de las vesículas extracelulares.

Disponible en: Plos One

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