Isolation of human fibroadipogenic progenitors and satellite cells from frozen muscle biopsies

Altres ajuts: Association Française contre les Myopathies (22525)Altres ajuts: Fundación Isabel GemioSkeletal muscle contains multiple cell types that work together to maintain tissue homeostasis. Among these, satellite cells (SC) and fibroadipogenic progenitors cells (FAPs) are the two main stem cell pools. Studies of these cells using animal models have shown the importance of interactions between these cells in repair of healthy muscle, and degeneration of dystrophic muscle. Due to the unavailability of fresh patient muscle biopsies, similar analysis of interactions between human FAPs and SCs is limited especially among the muscular dystrophy patients. To address this issue here we describe a method that allows the use of frozen human skeletal muscle biopsies to simultaneously isolate and grow SCs and FAPs from healthy or dystrophic patients. We show that while the purified SCs differentiate into mature myotubes, purified FAPs can differentiate into adipocytes or fibroblasts demonstrating their multipotency. We find that these FAPs can be immortalized and the immortalized FAPs (iFAPs) retain their multipotency. These approaches open the door for carrying out personalized analysis of patient FAPs and interactions with the SCs that lead to muscle loss

A blood-based multi-pathway biomarker assay for early detection and staging of Alzheimer's disease across ethnic groups

INTRODUCTION: Existing blood-based biomarkers for Alzheimer's disease (AD) mainly focus on its pathological features. However, studies on blood-based biomarkers associated with other biological processes for a comprehensive evaluation of AD status are limited. METHODS: We developed a blood-based, multiplex biomarker assay for AD that measures the levels of 21 proteins involved in multiple biological pathways. We evaluated the assay's performance for classifying AD and indicating AD-related endophenotypes in three independent cohorts from Chinese or European-descent populations. RESULTS: The 21-protein assay accurately classified AD (area under the receiver operating characteristic curve [AUC] = 0.9407 to 0.9867) and mild cognitive impairment (MCI; AUC = 0.8434 to 0.8945) while also indicating brain amyloid pathology. Moreover, the assay simultaneously evaluated the changes of five biological processes in individuals and revealed the ethnic-specific dysregulations of biological processes upon AD progression. DISCUSSION: This study demonstrated the utility of a blood-based, multi-pathway biomarker assay for early screening and staging of AD, providing insights for patient stratification and precision medicine. HIGHLIGHTS: The authors developed a blood-based biomarker assay for Alzheimer's disease. The 21-protein assay classifies AD/MCI and indicates brain amyloid pathology. The 21-protein assay can simultaneously assess activities of five biological processes. Ethnic-specific dysregulations of biological processes in AD were revealed

Evaluación de la fibrosis hepática en la hepatitis crónica por virus C mediante la aplicación prospectiva del Sabadell's NIHCED score: Sabadell's Non Invasive, Hepatitis C Related-Cirrhosis Early Detection Score Prospective evaluation of liver fibrosis in chronic viral hepatitis C infection using the Sabadell NIHCED: non-invasive hepatitis C related cirrhosis early detection) index

Introducción: la hepatitis crónica por VHC cursa de forma asintomática desarrollando cirrosis hepática y sus complicaciones en un 20-40% de los casos. En estudios previos se ha demostrado que la fibrosis avanzada es un factor pronóstico fundamental. El método gold standard para la valoración del grado de fibrosis es la biopsia hepática. Nuestro grupo ha validado un índice predictivo, el NIHCED (Sabadell's Non Invasive, Hepatitis C related-Cirrosis Early Detection Score), basado en datos demográficos, analíticos y ecográficos para determinar la presencia de cirrosis. Objetivo: nuestro objetivo es el de evaluar si el NIHCED predice la presencia de fibrosis avanzada en los pacientes con hepatitis crónica por virus C. Material y métodos: estudio prospectivo donde se incluyeron pacientes con hepatitis crónica por VHC. Se les realizó una biopsia hepática y el NIHCED. El grado de fibrosis se correlacionó con el valor del NIHCED mediante curva de ROC y el coeficiente de correlación de Spearman. Resultados: se incluyeron un total de 321 pacientes (ratio hombre/mujer 1,27) con una edad media de 48 &plusmn; 14 años. La biopsia hepática mostró que 131 (30,5%) no tenían fibrosis o era expansión portal, mientras que 190 (69,5%) tenían fibrosis avanzada o cirrosis. Para un punto de corte de 6 puntos, la sensibilidad fue del 72%, especificidad del 76,3%, VPP del 81%, VPN del 63,7% y una precisión diagnóstica del 72,5%, con un área bajo la curva fue de 0,787 y un coeficiente de correlación de Spearman de r = 0,65. Conclusiones: el NIHCED predice la presencia de fibrosis avanzada en un elevado porcentaje de pacientes sin necesidad de realizar biopsia hepática.<br>Introduction: liver disease resulting from chronic hepatitis C virus (HCV) infection follows an asymptomatic course towards cirrhosis and its complications in 20-40% of cases. Earlier studies demonstrated that advanced fibrosis is a prognostic factor. The "gold standard" for the evaluation of fibrosis grade is liver biopsy. Our group validated a predictive index - NIHCED - based on demographic, laboratory parameters, and echoghraphic data to determine the presence of cirrhosis. Objective: our objective is to evaluate whether the NIHCED score predicts the presence of advanced fibrosis in patients with chronic HCV infection. Material and methods: this prospective study included patients with chronic HCV infection who underwent liver biopsy and were administered the NIHCED score. Fibrosis grade correlated with the NIHCED score using the ROC curve analysis and Spearman's correlation coefficient. Results: in total 321 patients were included (male/female ratio 1.27) with a mean age of 48 &plusmn; 14 years. Liver biopsy showed that 131 (30.5%) had no fibrosis or had portal expansion while 190 (69.5%) had advanced fibrosis or cirrhosis. At a cut-off point of 6, sensitivity was 72%, specificity was 76.3%, positive predictive value (PPV) was 81%, negative predictive value (NPV) was 63.7%, and diagnostic accuracy was 72.5%, with an area under the curve (AUC) of 0.787, and a Spearman's correlation coefficient of r = 0.65. Conclusions: the NIHCED score predicts the presence of advanced fibrosis in an elevated percentage of patients with a need of liver biopsy

Bone marrow transplantation in dysferlin-deficient mice result in a mild functional improvement

Dysferlinopathies are caused by mutations in the DYSF gene. Dysferlin is a protein mainly expressed in the skeletal muscle and monocytes. Cell therapy constitutes a promising tool for the treatment of muscular dystrophies. The aim of our study was to evaluate the effect of bone marrow transplantation (BMT) using the A/J Dysf(prmd) mouse model of dysferlinopathy. For that purpose, we studied dysferlin expression by western blot and/or immunohistochemistry in transplanted mice and controls. Computerized analyses of locomotion and electrophysiological techniques were also performed to test the functional improvement. We observed dysferlin expression in splenocytes, but not in the skeletal muscle of the transplanted mice. However, the locomotion test, electromyography studies, and muscle histology showed an improvement in all transplanted mice that was more significant in the animals transplanted with dysferlin?/? cells. In conclusion, although BMT restores dysferlin expression in monocytes, but not in skeletal muscle, muscle function was partially recovered. We propose that the slight improvement observed in the functional studies could be related with factors, such as the hepatocyte growth factor, released after BMT that prevented muscle degeneratio

Les inhibiteurs de la voie des Janus-kinases : un traitement prometteur de la dermatomyosite pour inhiber de la voie de l’interféron,

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The FTD-like syndrome causing TREM2 T66M mutation impairs microglia function, brain perfusion, and glucose metabolism.

Genetic variants in the triggering receptor expressed on myeloid cells 2 (TREM2) increase the risk for several neurodegenerative diseases including Alzheimer&#39;s disease and frontotemporal dementia (FTD). Homozygous TREM2 missense mutations, such as p.T66M, lead to the FTD-like syndrome, but how they cause pathology is unknown. Using CRISPR/Cas9 genome editing, we generated a knock-in mouse model for the disease-associated Trem2 p.T66M mutation. Consistent with a loss-of-function mutation, we observe an intracellular accumulation of immature mutant Trem2 and reduced generation of soluble Trem2 similar to patients with the homozygous p.T66M mutation. Trem2 p.T66M knock-in mice show delayed resolution of inflammation upon in vivo lipopolysaccharide stimulation and cultured macrophages display significantly reduced phagocytic activity. Immunohistochemistry together with in vivo TSPO small animal positron emission tomography (&mu;PET) demonstrates an age-dependent reduction in microglial activity. Surprisingly, perfusion magnetic resonance imaging and FDG-&mu;PET imaging reveal a significant reduction in cerebral blood flow and brain glucose metabolism. Thus, we demonstrate that a TREM2 loss-of-function mutation causes brain-wide metabolic alterations pointing toward a possible function of microglia in regulating brain glucose metabolism