We investigated the expression of proteoglycans (PGs) and hyaluronan (HA) during healing of human mucosal wounds. Biopsy specimens of experimental wounds were taken 1, 3, and 7 days after wounding. Frozen sections were used for immunolocalization of CD44, syndecan-1, basement membrane-associated heparan sulfate proteoglycan (BM-HSPG), decorin, and biglycan. HA was localized in paraffin sections with a specific HA-binding probe. Epithelium showed first signs of migration on Day 1, more progressive migration on Day 3, and epithelial sheets confronted on Day 7. CD44 surrounded migrating keratinocytes at all stages of wound healing. In epithelium, CD44 and HA remarkably localized to the same region. Expression of syndecan-1 was switched from the suprabasal cell layer of unwounded epithelium to the basal cell layer of the migrating wound epithelium. BM-HSPG was absent under migrating keratinocytes. It started to reappear at the basement membrane zone on Day 7. The area under the wound epithelium containing newly synthesized collagen fibers first became positive for decorin on Day 7, whereas staining of biglycan was negative. Granulation tissue was also strongly positive for CD44 and hyaluronan. Our results indicate that migrating keratinocytes express both CD44 and syndecan-1 but not BM-HSPG. During differentiation of keratinocytes, expression of CD44 preceded that of syndecan-1. The results suggest that different HSPGs have multiple functions in keratinocyte migration and differentiation during reepithelialization.

Proteoglycans (PGs) are extracellular and cell surface-associated macromolecules that regulate cell adhesion, cell growth, matrix formation, and bind growth factors. In this work we studied the distribution of core proteins of four PGs (decorin, biglycan, a large molecular weight PG, and CD44) in human gingiva and periodontal ligament by immunohistochemical staining of frozen tissue sections with specific antibodies. Decorin, a major PG of this tissue, was localized on collagen fiber bundles in the gingival and periodontal connective tissues. Staining for decorin was most intense at the subepithelial region. Biglycan was a minor PG component of the human periodontium, showing some accumulation in connective tissue under the oral epithelium. At the immunohistochemical level, biglycan appeared to form fine filament-like structures on extracellular matrix fibers. Localization of large molecular weight PG differed from that of decorin and biglycan. It was concentrated in deep connective tissue areas of the gingiva and in the periodontal ligament, and was only weakly present at the subepithelial region. CD44 was mainly concentrated in cell-cell contact areas of basal and spinous layers of oral epithelium. In the connective tissue of gingiva and periodontal ligament, CD44 was localized on fibroblast cell surfaces. Connective tissue area under the junctional epithelium contained relatively small amounts of PGs. The results indicate that different parts of human periodontium contain a typical variety of PGs, suggesting a specific function for each PG species in the location at which they accumulate.

We conclude that enhancement of outflow facility by nitrosocaptopril, SNP and 8-Br-cGMP, their second messenger derivative, at least partly explains the IOP-lowering effect of NO releasing compounds.

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To our knowledge the present findings constitute the first evidence of ACE2 activity in the ciliary and vitreous bodies, in addition to previously described activity in the retina. The known favorable effects of ACE2 products vs. those of ACE1 suggest a counterbalancing interaction of these two enzyme homologues in physiological regulation of ocular circulation and pressure and possible protective role in certain ophthalmic disorders such as glaucoma and diabetic retinopathy.