Abstract MP03: Intracerebroventricular Administration Of Autologous Bone Marrow-derived Cells Attenuate Inflammation And Increase In AT1 Receptor In The Brain Of Angiotensin II Initiated Hypertensive Rats

Abstract

Objectives: Bone marrow-derived cells (BMCs) include mesenchymal stem cells (MSC) play critical role in repairing damaged tissue and anti-inflammation. We reported that intracerebroventricular (icv) administration of autologous BMCs attenuate slow pressor Ang II initiated hypertension via attenuating Ang II mediated sympathetic activation in rats. However, mechanisms of this observation have not been elucidated. We hypothesized that BMCs in the brain would attenuate inflammation and modulate overactive renin angiotensin system (RAS) in the brain of Ang II initiated hypertensive rats. Therefore we examined characteristics of BMCs prepared with identical cultural condition to previous experiment and examined expression of inflammation related cytokines and RAS component in the brain of Ang II initiated hypertensive rats. Methods: Aspirated bone marrow cells underwent red blood cell lysis protocol were seeded in an individual dish in Dulbecco Modified Eagle Media with 10% fetal bovine serum. Floating cells were removed and plastic adherent cells were allowed to glow for 3 weeks at passage 3. The number of BMCs proliferated more than 10 6 were used for immunocytochemical, flowcytometric, BrdU uptake, and Western blot analysis. TGF-beta, IL-10 and AT1 receptor protein expression were examined in brains of Ang II initiated hypertensive rats. Results: Cultured BMCs expressed CD29, a marker of mesenchymal stem cell. Flowcytometric analysis revealed that 38% of BMCs were CD29+ CD34-. Endothelial cell (EC) proliferation assay exhibited 52% higher BrdU uptake with conditioned media from BMCs than the media from ECs. Expression of angiotensin converting enzyme (ACE) was 87% lower in BMCs than in ECs, whereas ACE2 expression was 142% higher in BMCs. Furthermore, Ang II infusion significantly increased expression of TGF-beta and AT1 receptor in the brain by 146% and 135% respectively and icv administration of BMCs attenuated the increases of both expressions (39%, 59% respectively). Ang II infusion with or without BMCs icv did not affect to IL-10 expression in the brain. Conclusion: BMCs in the brain may have protective role against Ang II induced sympathetic activation via attenuation of brain inflammation and increase in AT1 receptors.