Purchase this article with an account.
T. Chan-Ling, S. Hughes; Characterization of Smooth Muscle Cell and Pericyte Differentiation in the Rat Retina in vivo . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2094.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: To characterise pericyte and smooth muscle cell (SMC) differentiation in the developing rat retinal vasculature and to examine their role in vessel stabilisation. Methods: Retinas from embryonic day (E) 20 to adult rats were multiple labelled immunohistochemically with antibodies to NG2, desmin, alpha–smooth muscle actin (SMA), calponin, and caldesmon. To examine whether immature mural cells conferred resistance to hyperoxia post-natal day (P) 3 rats were exposed to 70%-80% oxygen for 48 hrs. Results: At E20, NG2 positive mural precursor cells (MPCs) were present. These gave rise to both pericytes and arterial, arteriolar and venous SMCs via different developmental pathways and intermediate phenotypes. Differentiation of SMCs as determined by the onset of SMA expression, was coincident with selection of major vessels from the primordial capillary bed. Maturation of arterial smcs was indicated by the expression of calponin and caldesmon, proteins thought to regulate SMC contraction. In the adult vasculature a significant proportion of pericytes did not express SMA. Immature mural cells did not prevent hyperoxia induced vessel regression. Rather, resistance to hyperoxia was coincident with the SMC expression of caldesmon and calponin and the differentiation of SMCs on arterioles. Conclusions: Developing mural cells are extremely plastic and appear to respond to environmental cues. Our results suggest that their phenotype is determined by the nature of the associated vascular segment and hemodynamic factors. Studies of angiogenesis in disease and transgenics need to be interpreted in light of the significant mural cell heterogeneity demonstrated in this study. Contrary to previous studies (Benjamin et al., 1998) concluding that ensheathment by SMA positive pericytes prevents vascular remodelling, our results suggest that resistance to hyperoxia-induced vaso-obliteration and vessel stabilisation may be due to the functional maturation of SMCs and their consequent ability to regulate blood flow. Benjamin, L. E. et al. (1998) Development 125:1591-1998.
This PDF is available to Subscribers Only