Bone Abstracts

Success in periodontal regeneration through guided tissue regeneration relies on the healing capacity of the host tissue. Platelet preparations are mitogenic and stimulate regeneration through high growth factor levels. Here we assessed collagen barrier membranes (CBM) as carriers for the secretome of activated platelets. We evaluated cell-attachment, the release of the secretome, and cell proliferation.

Secretome of washed platelets (washed PSEC) and unwashed platelets (unwashed PSEC) was lyophilized on CBM. Then morphology was evaluated by scanning electron microscopy. Cell attachment was measured with fluorescence microscopy based on DiI-labeled cells. To measure the release kinetic we collected supernatants from the loaded CBM. The mitogenic effect was evaluated in a bioassay using fibroblasts of the gingiva and periodontal ligament. Total protein release was assessed using the BCA assay. The release of growth factors was investigated based on PDGF-BB and TGFβ1 ELISAs. To reveal if CBM maintain mitogenic activity cells were seeded onto the washed CBM and proliferation was measured.

The morphology of CBM and cell attachment was not modulated by lyophilizing washed and unwashed PSEC onto the CBM. Supernatants taken after 1 h induced a mitogenic response in fibroblasts and showed the highest total protein, TGFβ1 and PDGF-BB content. The effect on proliferation, total protein, and growth factor release decreased rapidly as observed in subsequent supernatants taken after hour 3, 6, 24, and 48. Supernatants of CBM loaded with unwashed PSEC stimulated proliferation more than supernatants from CBM loaded with washed PSEC. CBM loaded with washed and unwashed PSEC increased proliferation when cells where seeded directly onto the membranes after 48 h of washing.

CBM release growth factors in a burst-like release kinetic with a peak in the first hour and maintain their mitogenic capacity. Taken together our results suggest a two-phasic mitogenic activity of CBM loaded with PSEC.