A morphological study on the response between primary periosteum cultures and synthetic hydroxyapatite particles

Concise review: the periosteum: tapping into a reservoir of clinically useful progenitor cells

Elucidation of the periosteum and its regenerative potential has become a hot topic in orthopedics. Yet few review articles address the unique features of periosteum-derived cells, particularly in light of translational therapies and engineering solutions inspired by the periosteum's remarkable regenerative capacity. This review strives to define periosteum-derived cells in light of cumulative research in the field; in addition, it addresses clinical translation of current insights, hurdles to advancement, and open questions in the field. First, we examine the periosteal niche and its inhabitant cells and the key characteristics of these cells in the context of mesenchymal stem cells and their relevance for clinical translation. We compare periosteum-derived cells with those derived from the marrow niche in in vivo studies, addressing commonalities as well as features unique to periosteum cells that make them potentially ideal candidates for clinical application. Thereafter, we review the differentiation and tissue-building properties of periosteum cells in vitro, evaluating their efficacy in comparison with marrow-derived cells. Finally, we address a new concept of banking periosteum and periosteum-derived cells as a novel alternative to currently available autogenic umbilical blood and perinatal tissue sources of stem cells for today's population of aging adults who were "born too early" to bank their own perinatal tissues. Elucidating similarities and differences inherent to multipotent cells from distinct tissue niches and their differentiation and tissue regeneration capacities will facilitate the use of such cells and their translation to regenerative medicine.

Bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) transfection to human periosteal cells enhances osteoblast differentiation and bone formation

Periosteum has been demonstrated to contain mesenchymal progenitor cells differentiating to osteoblasts, and both bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) may play important roles in cell-based approaches to bone regeneration. The purpose of this study was to evaluate the feasibility and efficacy of BMP-2 and/or VEGF on periosteal cell differentiation to osteoblasts in vitro and ectopic bone formation in vivo. Human periosteum-derived cells were transfected with BMP-2, VEGF, BMP-2 + VEGF, or vehicle as a control by non-viral gene transfer and then cultured and implanted to nude mice intramuscularly. Real-time polymerase chain reaction analysis of the culture revealed that transgenes for BMP-2 and BMP-2 + VEGF induced more mRNA expression of alkaline phosphatase, collagen type I, and osteocalcin than VEGF and vehicle treatments; additionally, alizarin red S staining, alkaline phosphatase staining, and alkaline phosphatase activity were significantly higher in the BMP-2 + VEGF transgene than in the other versions. After implantation, ectopic bone was observed at 4 weeks and greatly increased at 8 weeks in all groups. In particular, the combination of BMP-2 and VEGF formed significantly more bone at 4 weeks, and VEGF transfection resulted in more blood vessels relative to the conditions without VEGF. Thus, VEGF might enhance BMP2-induced bone formation through modulation of angiogenesis.

Periosteal cells in bone tissue engineering

In 1742, H.L. Duhamel published a report in which the osteogenic function of periosteum was described. In 1932 H.B. Fell was the first to successfully culture periosteum; Fell concluded that this tissue might have the capability to form mineralized tissue in vitro. In the 1990s the research group of A.L. Caplan pioneered work exploring the osteogenic potential of periosteal cells in the field of bone engineering. On the basis of these studies a number of research groups have developed hard tissue generation concepts that aim to repeat the clinical success of bone autografts by culturing cells from periosteum and seeding a sufficient quantity of those cells into scaffolds made of biomaterials of natural and synthetic origin. The highly porous matrices support the induction of bone regeneration by creating and maintaining a space that facilitates progenitor cell migration, proliferation, and differentiation as well as graft revascularization. In this way, a host tissue-scaffold cell interphase might be created that allows reproduction of the intrinsic properties of autogenous bone, including the ability to be incorporated into the surrounding host bone and to continue normal bone-remodeling processes. This review discusses the history and state of the art of bone tissue engineering from a periosteum and periosteal cell source point of view and attempts to indicate future research directions.