Research Information System
American Thoracic Society (ATS), United States Of America, 1 - 04 May 2012, pp.345, (Summary Text)
RATIONALE: Idiopathic pulmonary arterial hypertension (IPAH) is a progressive disease and the pathobiology is typified by cell proliferation, inflammation and vascular remodeling. Hyaluronan (HA), a large glycosaminoglycan found in the extracellular matrix, has major roles in lung and vascular biology and disease. We have previously demonstrated that pulmonary artery smooth muscle cells (PASMCs) from IPAH lungs spontaneously produce high levels of HA. We hypothesized that HA produced by PASMCs contributes to their contractility. METHODS: PASMCs were obtained from explanted lungs. Human PASMC were isolated from elastic pulmonary arteries (>500-um diameter) dissected from lungs obtained at explantation during lung transplant. The collagen gel contraction assay was used as a measure of cell contractility. Circular agarose molds were prepared using 10-mm diameter cloning cylinders and 3% agarose solution. A solution of rat-tail collagen was mixed with PASMCs (3 x 105/ml) suspended in SmGM supplemented with 10% FBS and antibiotics, and the PASMC-collagen mixture was pipetted into circular agarose molds of 24-well tissue culture plates. Gels were polymerized at 37°C for 1 h, overlaid with 1 ml of conditioned media, gently detached from the sides and bottom of the mold with a spatula, and allowed to contract as suspended gels for 16 h. In some experiments cells were cultured with addition of hyaluronidase. The gels were scanned and the gel area was measured using Image J software and expressed as percentage of gel area on the image. RESULTS: Collagen gel contraction assay showed that IPAH PASMCs contract a collagen gel to a greater extent compared to control PASMCs [Percentage of gel area on the image (mean±SD): IPAH 31±3, Control; 46±5 p<0.0001]. Treatment of IPAH PASMCs with hyaluronidase resulted in a contraction response that is more similar to control cells [Percentage of gel area on the image (mean±SD): IPAH PASMC 32±1.2, IPAH PASMC with Hyaluronidase; 40±1.3 p<0.01]. Treatment of control PASMC with hyaluronidase did not change their contraction properties significantly [Percentage of gel area on the image (mean±SD): Control PASMC 57±4, Control PASMC with Hyaluronidase; 53±2 p=0.37] CONCLUSIONS: HA produced by PASMC has important roles in PASMC contraction.