Senescent T Cell Induces Brown Adipose Tissue "Whitening" Via Secreting IFN-γ.

Aging-associated chronic inflammation is a key contributing factor to a cluster of chronic metabolic disorders, such as cardiovascular disease, obesity, and type 2 diabetes. Immune cells particularly T cells accumulate in adipose tissue with advancing age, and there exists a cross talk between T cell and preadipocyte, contributing to age-related adipose tissue remodeling. Here, we compared the difference in morphology and function of adipose tissue between young (3-month-old) and old (18-month-old) mice and showed the phenomenon of brown adipose tissue (BAT) "whitening" in old mice. Flow cytometry analysis suggested an increased proportion of T cells in BAT of old mice comparing with the young and exhibited senescent characteristics. We take advantage of coculture system to demonstrate directly that senescent T cells inhibited brown adipocyte differentiation of preadipocytes in adipose tissue. Mechanistically, both in vitro and in vivo studies suggested that senescent T cells produced and released a higher level of IFN-γ, which plays a critical role in inhibition of preadipocyte-to-brown adipocyte differentiation. Taken together, the data indicate that senescent T cell-derived IFN-γ is a key regulator in brown adipocyte differentiation.

Cystic tumour of the atrioventricular node: a case report and review of the literature / 中华医学杂志(英文版)

Cystic tumour of the atrioventricular node is a rare primary cardiac tumour that can cause complete heart block and sudden death. Here, we describe a male case aged 42 years who suddenly died without a medical and family history of cardiac illnesses. After detailed macroscopic and microscopic examinations, a cystic mass was found in the atrioventricular nodal region. The small lesion was less than 1 cm in diameter, and consisted of small and large cystic spaces and tubular structures lined by flat, cuboidal or squamous epithelium. Immunohistochemical staining revealed the tumour epithelium positive for epithelial membrane antigen, carcinoembryonic antigen, antigen epitopes AE1/AE3, cytokeratins CK5/6 and CK7, but negative for calretinin, HBME-1, Wilms' tumor 1, factor VIII, chromogranin, synaptophysin or smooth muscle actin, suggesting an endodermal rather than mesothelial origin.