Abstract 003: Cholinergic Expansion of an Inflammatory Macrophage Population in the Pre-Hypertensive Spontaneously Hypertensive Rat

Our laboratory previously identified an abnormally elevated CD161a+ immune cell population in splenocytes of the pre-hypertensive Spontaneously Hypertensive Rat (SHR) that was abnormally expanded following cholinergic activation with nicotine . In the present study, we tested the hypothesis that the expanded CD161a+ cell population represents an activated monocyte/macrophage population and are present in the bone marrow (BM). We isolated cells from the spleen and BM of pre-hypertensive (4-5 week old) SHR (n=3) and age-matched normotensive Wistar Kyoto (WKY, n=3) rats. Isolated cells were stained with a fluorochrome conjugated anti-rat CD161a monoclonal antibody and analyzed by flow cytometry. CD161a+ cells were more prevalent in splenocytes and BM of the pre-hypertensive SHR, compared to WKY (8.7 ± 1.4% vs 1.2 ± 0.6% and 12.6 ± 1.8% vs 1.7 ± 0.8%, respectively, p 0.05). Nicotine had no effect on the CD161a+/CD68- cell population in either splenocytes or BM cells of the SHR or WKY. Thus, an activated monocyte/macrophage population (CD161a+/CD68+) is expanded by cholinergic activation in both the BM and spleen of SHR, but only in the BM and not spleen of the WKY. Since, the pro-inflammatory nicotinic response present in the BM of the WKY is abrogated in the peripheral spleen, we conclude that the retention of this response in the SHR may contribute to the development of hypertension.