Figure 1.

Anatomy of the normal aorta adventitia and adjacent tissues. The normal adventitial layer of the mouse aorta constitutively contains T-cells (but no B-cells), tissue macrophages, cDCs, stromal cells or myofibroblasts, and mast cells. The adjacent tissues including the periaortic adipose tissue harbors fat-associated lymphoid clusters (FALCs) in wild-type mice. FALCs represent T/B-cell aggregates of various sizes that are exclusively observed in adipose tissue. In the adventitia, axons of both the sensory and the sympathetic nervous systems have been identified as well as vasa vasorum and lymph vessels. Ganglia of the peripheral nervous system are embedded in the adipose tissue, and their axons reach the external lamina that separates the adventitia from the media layer.