CD61 identifies a superior population of aged murine HSCs and is required to preserve quiescence and self-renewal.

ABSTRACT: Aging leads to a decline in function of hematopoietic stem cells (HSCs) and increases susceptibility to hematological disease. We found CD61 to be highly expressed in aged murine HSCs. Here, we investigate the role of CD61 in identifying distinct subpopulations of aged HSCs and assess how expression of CD61 affects stem cell function. We show that HSCs with high expression of CD61 are functionality superior and retain self-renewal capacity in serial transplantations. In primary transplantations, aged CD61High HSCs function similarly to young HSCs. CD61High HSCs are more quiescent than their CD61Low counterparts. We also show that in aged bone marrow, CD61High and CD61Low HSCs are transcriptomically distinct populations. Collectively, our research identifies CD61 as a key player in maintaining stem cell quiescence, ensuring the preservation of their functional integrity and potential during aging. Moreover, CD61 emerges as a marker to prospectively isolate a superior, highly dormant population of young and aged HSCs, making it a valuable tool both in fundamental and clinical research.

Influencia de la pandemia COVID-19 sobre la epidemiología de la bronquiolitis aguda / Influence of the COVID-19 pandemic on the epidemiology of acute bronchiolitis

Introducción: La pandemia COVID-19ha modificado la propagación de ciertos virus respiratorios causantes de bronquiolitis aguda. Analizamos la epidemiología de los ingresos por bronquiolitis durante la pandemia COVID-19 en comparación con ocho temporadas epidémicas anteriores. Métodos: Estudio observacional ambispectivo, que incluyó lactantes con bronquiolitis ingresados en un hospital terciario durante dos períodos: pandemia COVID-19 (15 de marzo de 2020 a 31 de agosto de 2021) y pre-pandemia (1 de septiembre de 2012 a 14 de marzo de 2020). Se recogieron características demográficas, clínicas y etiología. Resultados: Ingresaron 510 pacientes por bronquiolitis: 486 en el período pre-pandemia con una media de 61 ingresos por temporada vs. 24 durante la pandemia, observándose una reducción de ingresos del 60,7%. Durante la pandemia, el brote epidémico se inició con retraso abarcando la primavera-verano de 2021. El virus respiratorio sincitial fue el agente etiológico más frecuente en ambos períodos. Conclusiones: Observamos un cambio estacional de la bronquiolitis durante la pandemia COVID-19, probablemente influenciado por las medidas de control frente a SARS-CoV-2.(AU)

Introduction: The COVID-19 pandemic has changed the circulation of some viruses associated with acute bronchiolitis. We analyzed the epidemiology of bronchiolitis admissions during the COVID-19 pandemic compared with 8 previous epidemic seasons. Methods: An observational and ambispective study was performed, including infants admitted with bronchiolitis in a tertiary hospital during 2 periods: COVID-19 pandemic (15th March 2020 to 3rd August 2021) and pre-pandemic (1st September 2012 to 14th March 2020). Demographic, clinical data and etiologies were collected. Results: Five hundred ten patients were hospitalized with bronchiolitis: 486 in the pre-pandemic period with an average of 61 admissions per season vs. 24 during the pandemic, observing a 60.7% reduction in bronchiolitis admissions. During the pandemic, bronchiolitis outbreak was delayed until spring–summer 2021. Respiratory syncytial virus was the most frequent etiological agent in both periods. Conclusion: We observed a change in the seasonality of bronchiolitis during the pandemic COVID-19, possibly influenced by control measures against SARS-CoV-2..(AU)

Analysis of centrosomal area actin reorganization and centrosome polarization upon lymphocyte activation at the immunological synapse.

T cell receptor (TCR) and B cell receptor (BCR) stimulation of T and B lymphocytes, by antigen presented on an antigen-presenting cell (APC) induces the formation of the immunological synapse (IS). IS formation is associated with an initial increase in cortical filamentous actin (F-actin) at the IS, followed by a decrease in F-actin density at the central region of the IS, which contains the secretory domain. This is followed by the convergence of secretion vesicles towards the centrosome, and the polarization of the centrosome to the IS. These reversible, cortical actin cytoskeleton reorganization processes occur during lytic granule secretion in cytotoxic T lymphocytes (CTL) and natural killer (NK) cells, proteolytic granules secretion in B lymphocytes and during cytokine-containing vesicle secretion in T-helper (Th) lymphocytes. In addition, several findings obtained in T and B lymphocytes forming IS show that actin cytoskeleton reorganization also occurs at the centrosomal area. F-actin reduction at the centrosomal area appears to be associated with centrosome polarization. In this chapter we deal with the analysis of centrosomal area F-actin reorganization, as well as the centrosome polarization analysis toward the IS.

[Influence of the COVID-19 pandemic on the epidemiology of acute bronchiolitis]. / Influencia de la pandemia COVID-19 sobre la epidemiología de la bronquiolitis aguda.

Introduction: The COVID-19 pandemic has changed the circulation of some viruses associated with acute bronchiolitis. We analyzed the epidemiology of bronchiolitis admissions during the COVID-19 pandemic compared with 8 previous epidemic seasons. Methods: An observational and ambispective study was performed, including infants admitted with bronchiolitis in a tertiary hospital during 2 periods: COVID-19 pandemic (15th March 2020 to 3 rd August 2021) and pre-pandemic (1st September 2012 to 14th March 2020). Demographic, clinical data and etiologies were collected. Results: Five hundred ten patients were hospitalized with bronchiolitis: 486 in the pre-pandemic period with an average of 61 admissions per season vs. 24 during the pandemic, observing a 60.7% reduction in bronchiolitis admissions. During the pandemic, bronchiolitis outbreak was delayed until spring-summer 2021. Respiratory syncytial virus was the most frequent etiological agent in both periods. Conclusion: We observed a change in the seasonality of bronchiolitis during the pandemic COVID-19, possibly influenced by control measures against SARS-CoV-2.

Influence of the COVID-19 pandemic on the epidemiology of acute bronchiolitis.

INTRODUCTION: The COVID-19 pandemic has changed the circulation of some viruses associated with acute bronchiolitis. We analyzed the epidemiology of bronchiolitis admissions during the COVID-19 pandemic compared with 8 previous epidemic seasons. METHODS: An observational and ambispective study was performed, including infants admitted with bronchiolitis in a tertiary hospital during 2 periods: COVID-19 pandemic (15th March 2020 to 3rd August 2021) and pre-pandemic (1st September 2012 to 14th March 2020). Demographic, clinical data and etiologies were collected. RESULTS: Five hundred ten patients were hospitalized with bronchiolitis: 486 in the pre pandemic period with an average of 61 admissions per season vs 24 during the pandemic, observing a 60.7% reduction in bronchiolitis admissions. During the pandemic, bronchiolitis outbreak was delayed until spring-summer 2021. Respiratory syncytial virus was the most frequent etiological agent in both periods. CONCLUSION: We observed a change in the seasonality of bronchiolitis during the pandemic COVID-19, possibly influenced by control measures against SARS-CoV-2.