Abstract 075: Proinflammatory T Helper 17 Cells as an Indicator of Hypertension

Objectives: T cells and interleukin 17 (IL17) have been shown to be critical in the development of hypertension (HTN). This implicates a significant role of IL17 producing T helper 17 (Th17) cells in HTN. Thus, the objective of our study was to investigate if Th17 cell levels in the peripheral blood (PB) and the bone marrow (BM) are correlated with blood pressure. Methods: Saline or Ang II was chronically infused into C57BL6 mice (1000ng Ang II/kg/min using osmotic pumps) for 3 weeks. This resulted in an increase in MAP of 45±10 mmHg. BM and PB from saline and Ang II-treated mice were analyzed using FACS. A parallel human study was conducted using blood samples obtained from hypertensive patients (n = 8, systolic BP ≥125 mmHg) and normotensive subjects (n = 10, systolic BP Results: We observed 87% and 36% increases in both Sca-1 + c-Kit + Lin - hematopoietic stem cell (HSC; 0.23±0.04% vs. 0.43±0.05%) and Sca-1 + c-Kit - Lin - lymphoid progenitors (10.8±1.1% vs. 14.7±2.9%) in the BM of Ang II infused mice. These are upstream stem/progenitor cells for T cells. This was associated with 30% and 190% increases in CD4 + IL17 + Th17 cells in the BM and PB (1.20±0.09% vs. 1.61±0.19 % and 4.8±2.0 % vs. 14.7±3.8 % respectively) in the Ang II infused mice. Importantly, there were 58% and 206% increases of angiotensin II type 1 receptor (AT1R) expressing CD4 + T cells in the BM and PB of Ang II HTN mice (0.40±0.04 % vs. 0.63±0.14 % and 1.1±0.2 % vs 3.4±1.1 % respectively) and ~ 85% of these cells were also positive for IL-17. Consistent with mouse data, analysis of PB showed a 470% increase of Th17 cells in HTN patients (0.48±0.18 % vs 2.72±1.2%). Conclusions: We observed (i) Increased hematopoietic stem/progenitor cells in Ang II HTN mice; (ii) increased Th17 cells in both HTN mice and humans and (iii) the majority of AT1R expressing CD4 + T cells was Th17 cells. Taken together, these observations indicate that Th17 cells may be an important indicator of those destined to develop HTN and suggest that these cells may represent a novel therapeutic target.