Ectopic osteogenesis and hematopoiesis after implantantion of bone marrow cells seeded on HAP/PLLA scaffold

Abstract

Bone tissue reconstruction and reparation is a big challenge in medicine. Biocomposite materials based on hidroxyapatite are widely used in reparation of bone defects. Adult bone marrow-derived stem cells may be considered in two categories: hematopoietic stem cells (HSC) from the bone marrow and mesenchymal stem cells from the bone marrow stroma (BMSC). HSC and BMSC do not only coexist in one organ, but functionally cooperate. BMSC have a critical role in the formation of hematopoietic microenvironment (HME). The aim of this study was to investigate the interactions between bone marrow cells and biocomposites based on HAp/PLLA (hidroxyapatite/poly-L-lactide) after subcutaneous implantation in Balb/c mice. In that purpose, bone marrow cells of Balb/c mice were seeded in HAp/PLLA tubes (15 mm×1,5 mm). The HAp/PLLA tubes with BMC was subcutaneously implanted with a needle into the intrascapsular region of the mouse. Implants were extracted after 2, 6 and 12 weeks. In implants after 2 and 6 weeks we found angiogenesis, collagenogenesis and new bone. Ectopic hematopoiesis was seen in implants after 12 weeks from implantation. As a good scaffold in the role of supporting osteogenesis and hematopoiesis, biocomposites HAp/PLLA can be good bone substitute materials in the bone reparation process. These results showed that the HAp/PLLA scaffold owned biological properties comparable to natural bone.

Keywords

• bone marrow cells
• HAP/PLLA
• implant
• osteogenesis
• hematopoiesis