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Oulun yliopiston väitöskirjat

HEALING OF CRANIAL CRITICAL SIZED DEFECTS WITH GRAFTS, STEM CELLS, GROWTH FACTORS AND BIO-MATERIALS, ACTA UNIVERSITATIS OULUENSIS D Medica 1386

ISBN-13:	978-952-62-1342-2
Kieli:	englanti
Kustantaja:	Oulun yliopisto
Oppiaine:	Lääketiede
Painos:	Osajulkaisuväitöskirjan yhteenveto-osa
Painosvuosi:	2016
Sijainti:	Print Tietotalo
Sivumäärä:	112
Tekijät:	LAPPALAINEN OLLI-PEKKA

22.50 €

Bone is a highly vascularized tissue which enables a close interaction between blood vessels and osteoid complexes, including osteoblasts and osteoclasts. Iatrogenic bone loss, caused by a surgical intervention or trauma, disrupts circulation in the bone and leads to hypoxia and even necrosis of the adjacent bone. The mechanisms of the bone tissue healing process by regeneration are highly specific. The most common and predictable way to manage a large-sized skull bone defect has traditionally been using the patient’s own bone tissue graft. The problem with the method is damage and pain of the donor site caused by the operation and healing problems. In paediatric patients, there is a limited availability of adequate autologous bone grafts. For this reason, efforts have been made to develop substitute materials in order to avoid the need for large bone grafts. Autologous stem cells have proven to be promising targets for the development of bone substitutes for cranio-maxillofacial bone defects. The main objective of this study was to examine, by using an experimental animal model, differences in the healing of critical-sized calvarial bone defects, similar to cranioplasty, induced with different types of autogenous bone grafts and with adipose tissue- or bone marrow-derived stem cells grown in two commonly used biomaterials, tricalcium phosphate and bioglass. We also investigated the effect of tissue adhesive, fibrin glue, on the healing process of bone defects. The effect of the stimulating growth factor proteins BMP-2, BMP-7 and VEGF on tissue transplants and ossification was also studied. The results of this study support the previously reported findings of accelerated bone graft resorption associated with autologous bone graft use. In particular, the use of fibrin tissue glue in combination with autologous particulated bone grafts reduced the formation of new bone in calvarial lesions. During the initial healing of calvarial bone defects, tricalcium phosphate granules proved to be more effective than solid bioactive glass scaffolds. Furthermore, in combination with adiposederived stem cells, tricalcium phosphate showed better bone regeneration than the same cells in combination with a bioactive glass scaffold. Combining bone marrow-derived stem cells with biomaterial did not increase bone formation in calvarial critical-sized defects. In this study, there was no evidence of the positive effect of growth factors on cranial bone healing.

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