Abstract 108: Sympathetic Inhibition Prevents the Homing of Specific Memory T Cells to the Bone Marrow and the Development of Repeated Hypertension

Effector memory T cells (T EM cells) play a crucial role in hypertension. Formed during an initial blood pressure surge, T EM cells can reside in bone marrow (BM) in a quiescent state for prolonged periods. Upon re-exposure to a hypertensive stimulus, these cells can be reactivated and aggravate hypertension and renal damage. Hypertension is also associated with elevated sympathetic outflow. We hypothesized that sympathetic nerves promote accumulation and reactivation of hypertension-specific T EM cells in the BM. We performed unilateral superior cervical ganglionectomy (SCGx) in C57BL/6 mice, causing sympathectomy of the forelimb on the surgical side. After 2-week Ang II infusion (490 ng/kg/min s.c.), 5х10 6 BM cells from both the SCGx and control limbs were isolated and co-cultured with 0.5х10 6 dendritic cells from other hypertensive mice. We found 30% fewer CD8 + T cell proliferation in the SCGx BM than intact side (1.9±0.2 vs. 2.8±0.1х10 4 , p+ T cells. To study mechanisms involved in T cell homing, 10 7 pan T cells were isolated from CD45.2 mice after Ang II infusion and adoptively transferred to CD45.1 mice with unilateral SCGx. Flow cytometry indicated that 35% fewer donor CD8 + T EM cells homed to the SCGx than the intact BM 7 days after transfer (5.3±0.8 vs. 8.1±1.5 per 10 4 total T cells, p