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J A Van Aalst

Publications and source records attributed to J A Van Aalst.

4 recordsLinked to original sources
PubMed2000

The migratory response to platelet-derived growth factor of smooth muscle cells isolated from synthetic vascular grafts in a canine model.

OBJECTIVE: Previous studies on smooth muscle cells (SMCs) harvested from implanted synthetic grafts demonstrate increased production of platelet-derived growth factor (PDGF) but decreased proliferative response compared with aortic SMCs. The purpose of this study was to determine the migratory response of graft versus aortic SMCs. METHODS: Thoracoabdominal grafts were implanted in beagles. The SMCs were harvested from the graft and infrarenal aorta. Migration was determined with the use of a razor-scrape assay and computerized image analysis. RESULTS: The mean distance migrated and the number of cells that migrated were greater in graft SMCs at baseline (185 +/- 18 micrometer and 108 +/- 17 cells) compared with aortic cells (110 +/- 10 micrometer and 42 +/- 5 cells)(P <.05). Baseline differences persisted after treatment with antibodies to PDGF. The addition of PDGF (10 ng/mL) resulted in increased migration in both graft (229 +/- 23 micrometer and 146 +/- 20 cells) and aortic SMCs (130 +/- 9 micrometer and 70 +/- 5 cells) compared with baseline (P <.05). The relative increase in response to PDGF was similar between the two groups (P = not significant). CONCLUSIONS: Graft SMCs differ phenotypically from aortic SMCs; they exhibit increased basal migration that is independent of autocrine stimulation by PDGF. In contrast to their blunted proliferative response, graft SMCs have a similar migratory response to PDGF compared with aortic SMCs.

Animals↗
PubMed2000

Regional differences in phorbol 12-myristate 13-acetate stimulation of PDGF production in the normal canine aorta.

OBJECTIVE: Platelet-derived growth factor (PDGF) is a potent smooth muscle cell mitogen implicated in the development of intimal hyperplasia and atherosclerosis. A regional variation in canine aortic production of PDGF (greater in the distal than in the proximal aorta) was demonstrated previously in organ culture. The response of aortic segments in organ culture, as well as of aortic endothelial cells and smooth muscle cells, to stimulators of PDGF secretion-phorbol 12-myristate 13-acetate (PMA) and thrombin-was assessed to elucidate whether these regional variations were due to intrinsic differences in the abilities of cells to produce PDGF. METHODS: Proximal and distal aortic segments were removed from 10 dogs and placed in organ culture, then treated with PMA or thrombin for 72 hours. PDGF in the conditioned media was measured by radioreceptor assay. RESULTS: PDGF production in the distal, unstimulated aorta was 2.5-fold higher than that in the proximal aorta (P <.05). Treatment of the proximal aorta with 10 nmol/L and 100 nmol/L PMA increased PDGF production twofold and threefold, respectively, whereas no increase with PMA treatment was seen in the distal aorta. After thrombin treatment, no increase in PDGF production was noted in the proximal aorta and only a minimal increase was noted in the distal aorta. Endothelial cells and smooth muscle cells (n = 6) were cultured from four aortic segments (ascending thoracic, descending thoracic, abdominal, and infrarenal) and treated with PMA. PDGF production by unstimulated endothelial cells from the infrarenal aorta was 2.5-fold higher (P <.01) than that from the ascending thoracic aorta. With PMA treatment, PDGF secretion increased in endothelial cells from all segments, the greatest percentage increase being observed in the proximal segments. Thrombin also increased PDGF release from endothelial cells, but with no regional variation. Unstimulated smooth muscle cells did not exhibit regional variation in PDGF production and did not increase PDGF secretion after treatment with PMA or thrombin. CONCLUSIONS: These findings suggest that endothelial cells in the aorta may have a differential capacity to produce PDGF in response to stimulants, reflecting intrinsic differences in endothelial cells from the proximal aorta versus the distal aorta, and this may account in part for the propensity of the distal aorta to develop atherosclerosis.

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