Decreased susceptibility of cultured smooth muscle cells from SHR rats to growth inhibition by heparin
✍ Scribed by Thérèse J. Resink; Timothy Scott-Burden; Ursula Baur; Maria Bürgin; Fritz R. Bühler
- Publisher
- John Wiley and Sons
- Year
- 1989
- Tongue
- English
- Weight
- 722 KB
- Volume
- 138
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
Smooth muscle cell proliferation is regulated through the coordinated action of growth inhibitors and growth factorslmitogens; a specific heparin-epidermal growth factor (ECF) complementation has been proposed (Reilly et al., 1987, J. Cell. Physiol., 13 1:149-157). In culture, vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) pro1 iferate more rapidly than VSMC from control Wistar Kyoto rats (WKY). We observed that, compared with WKY-derived VSMC, cells from SHR were markedly less susceptible to growth inhibition both by heparin and its homopolysaccharide analogue pentosan polysulphate (PPS). SHR-derived VSMC exhibited a reduced capacity for binding of [3H] heparin to specific extracellular surface receptors, whereas affinities for heparin were comparable between both VSMC isolates. The early (0-2 hr at 37°C) kinetics of internalization did not differ between SHR-and WKY-derived VSMC, but both internalized equivalent proportions (-10%) of initially surfacebound heparin. VSMC from SHR exhibited a greater capacity, without a changed affinity, for [1'25]ECF binding than VSMC from WKY. Pre-exposure of VSMC to heparin or PPS decreased, in a time-dependent manner, the EGF binding capacity for both SHR and WKY (by 40-50% after 72 hr). However, in absolute terms, the ECF-binding capacity of VSMC from SHR exposed to heparinoids was similar to that of nonexposed VSMC from WKY.