Migration of intervertebral disc cells into dense collagen scaffolds intended for functional replacement.

Invasion of cells from surrounding tissues is a crucial step for regeneration when using a-cellular scaffolds as a replacement of the nucleus pulposus (NP). The aim of current study was to assess whether NP and surrounding annulus fibrosus (AF) cells are capable of migrating into dense collagen scaffolds. We seeded freshly harvested caprine NP and AF cells onto scaffolds consisting of 1.5 and 3.0% type I collagen matrices, prepared by plastic compression, to assess cell invasion. The migration distance appeared both time and density dependent and was higher for NP (25%) compared to AF (10%) cells after 4 weeks. Migration distance was not enhanced by Hst-2, a peptide derived from saliva known to enhance fibroblast migration, and this was confirmed in a scratch assay. In conclusion, we revealed invasion of cells into dense collagen scaffolds and therewith encouraging first steps towards the use of a-cellular scaffolds for NP replacement.

[Saliva and wound healing]. / Speeksel en wondgenezing.

The oral mucosa is frequently exposed to mechanical forces, which may result in tissue damage. Saliva contributes to the repair of the oral mucosa in several ways. In the first place, it creates a humid environment to improve the function of inflammatory cells. During the last few years, it has been shown that saliva also contains a large number of proteins with a role in wound healing. Saliva contains growth factors, especially Epidermal Growth FACTOR, which promotes the proliferation of epithelial cells. Trefoil factor 3 and histatin promote the process of wound closure. The importance of Secretory Leucocyte Protease Inhibitor is demonstrated by the fact that in the absence of this salivary protein, oral wound healing is considerably delayed. Understanding these salivary proteins opens the way for the development of new wound healing medications.

Histatins enhance wound closure with oral and non-oral cells.

The role of human saliva in oral wound-healing has never been fully elucidated. We previously demonstrated that parotid-salivary histatins enhance in vitro wound closure. The question remains whether other salivary-gland secretions enhance wound closure, and also the effects of histatins on primary and non-oral cells. Since the presence of histatins is not limited to parotid saliva, we expected to observe wound-closure activity of other salivary-gland secretions. However, here we show that non-parotid saliva does not stimulate wound closure, most probably due to the presence of mucins, since the addition of MUC5B to parotid saliva abolished its effect. Furthermore, we found that histatins stimulated wound closure of (primary) cells of both oral and non-oral origin. This suggests that the cellular receptor of histatins is widely expressed and not confined to cells derived from the oral cavity. These findings encourage the future therapeutic application of histatins in the treatment of all kinds of wounds.