HUMAN AMNION EPITHELIAL CELLS REDUCE BLOOD PRESSURE AND PREVENT AORTIC INFLAMMATION AND COLLAGEN EXPRESSION DURING EXPERIMENTAL HYPERTENSION

Abstract

Objective: Vascular inflammation and fibrosis are hallmarks of hypertension and contribute to the development of cardiovascular disease. Current treatments for hypertension may reduce blood pressure but do not target the associated pathological changes and end-organ damage. Cell therapy has great therapeutic potential for many conditions as, unlike single pharmacological agents, cells can deliver multiple mediators which could more effectively target complex disease mechanisms. Human amnion epithelial cells (hAECs) have many properties (eg. anti-inflammatory, anti-fibrotic, regenerative and immunologically inert) that make them attractive candidates for a cell-based therapy for vascular pathology. This study aimed to test the potential of hAECs to treat vascular pathology in angiotensin II-induced hypertension. Design and method: Male C57Bl6 mice (8–12 weeks) were administered vehicle (saline; n = 35) or angiotensin II (0.7 mg/kg/d, n = 37) for 14 d via a subcutaneous osmotic minipump. After minipump implantation, a subset of mice were injected with 10^6 of hAECs intravenously. Systolic blood pressure was measured using tail-cuff; inflammation was assessed using flow cytometry and markers of fibrosis using quantitative PCR. Results: Angiotensin II infusion increased systolic blood pressure and promoted accumulation of aortic leukocytes, specifically macrophages and monocytes, which were elevated by ∼3-fold compared to vehicle-infused mice (n = 9–11, P < 0.05). Angiotensin II also increased aortic mRNA expression of collagen type 1 alpha 1 (Col1a1) by ∼4-fold and collagen type 5 alpha 1 (Col5a1) by ∼7-fold compared to vehicle (n = 6–8, P < 0.05). Co-administration of hAECs limited the development of hypertension by angiotensin II (185 ± 5 mmHg vs 165 ± 4 mmHg; n = 9–11, P < 0.05), as well as the aortic infiltration of macrophages and monocytes (n = 9–11, P < 0.05) and expression of Col1a1 and Col5a1 (n = 6–8, P < 0.05). Conclusions: Intravenous administration of hAECs blunted angiotensin II-induced hypertension, aortic inflammation and collagen expression in male mice. This study suggests that hAECs or their cellular products could be explored as treatments for vascular pathology during hypertension.