Secretion of growth factors from macrophages when cultured with microparticles

Macrophages' contribution to ectopic osteogenesis in combination with blood clot and bone substitute: possibility for application in bone regeneration strategies

PURPOSE

Given the great potential of macrophages in the processes of tissue repair and regeneration, the aim of our study was to examine the contribution that macrophages will have in osteogenic process when combined and implanted with blood clot (BC) and mineral bone substitute (MBS) in mice subcutaneous implantation model.

METHODS

Three types of implants were constructed and implanted subcutaneously into BALB/c mice: (1) RMBM implants (made of resident tissue macrophages, BC and MBS), (2) BM implants (made of BC and MBS), and (3) M implants (made of MBS only) where the last two served as control implants. One, two, four and eight weeks after implantation implants were explanted, and histochemical, immunohistochemical, and histomorphometric analyses were performed.

RESULTS

Increased vascularization, particularly pronounced two and four weeks after implantation and pronounced tissue infiltration in eight week term in RMBM implants compared with both other types, likewise the presence of osteoblast-like cells, osteoid-like structures, and more prominent osteopontin and osteocalcin immunoexpression in RMBM implants indicated more pronounced osteogenic process within them.

CONCLUSION

Our results suggest that macrophages deserve to be considered as a cell component when constructing implants in bone regenerative medicine strategies to improve bone fracture healing process.

Acemannan Induced Bone Regeneration in Lateral Sinus Augmentation Based on Cone Beam Computed Tomographic and Histopathological Evaluation

Acemannan, the major polysaccharide extracted from Aloe vera, is biomaterial that has demonstrated osteoinductive effects in vitro and in vivo. However, the effect of acemannan sponges on bone formation in open-type sinus augmentation has not evaluated. Here, we report a case study using radiographic and histological analyses to investigate the effect of acemannan on bone formation after lateral sinus lift surgery. The case was a 57-year-old female patient with an atrophic left posterior maxilla who underwent lateral sinus lift using an acemannan sponge using the two-stage procedure. In the first stage, an acemannan sponge was inserted through the bony window and placed between the antral floor and the elevated sinus membrane. Cone beam computed tomography (CBCT) images were taken immediately as baseline and 6-month postoperation for evaluation. A bone core specimen was also obtained for histological examination at the time of implant placement. The histological results revealed new bone formation, and the CBCT images demonstrated increased alveolar bone height at 6-month postoperation. Our findings suggest that an acemannan sponge could be a biomaterial for inducing bone formation in sinus lift surgery.