Hydraulic elevation of the periosteum: a novel technique for periosteal harvest.

Periosteum has been promoted as a potential substrate for tissue engineering. Its principal virtues are that it has a source of pluripotential mesenchymal cells and chondrogenic growth factors located in the cambium layer, and it can serve as a template for directional evolution of neo-tissue. The clinical use and in vitro study of periosteum-derived neo-tissue has been limited by the level of surgical skill required for harvest. Precise surgical technique, task-specific experience, adequate volume of procedures, and general surgical expertise are required for optimal harvest using the traditional periosteal elevator method. This report describes an easily mastered technique that preserves viability while providing the harvest of relatively large amounts of periosteum. Skeletally mature New Zealand white rabbits (11 males/20 tibias; 4 females/8 tibias; approximate weight 3.5 kg) and one Yucatan miniature pig were used for harvest of periosteum from the tibia using the traditional periosteal elevator and the developed hydraulic elevation approach. Histologic examination of the periosteal explants obtained by the developed method showed preservation of the cambium layer containing the progenitor cells necessary for the generation of neo-cartilage. This technique provides a simple method of harvesting large segments (>5 cm x 1 cm) of periosteum in a single procedure and may facilitate better exploitation of periosteum in tissue engineering.     

Extracorporeal shock wave‐induced proliferation of periosteal cells

The cambium cells of the periosteum are an important cell source for select tissue engineering/regenerative medicine applications due to their osteogenic and chondrogenic potential. However, the cambium layer is only 2–5 cells thick, which complicates its harvest, and the low cell number limits its suitability for certain applications. Extracorporeal shock waves (ESWs) have been reported to cause periosteal osteogenesis following cambium layer thickening. This study quantified the proliferation of cambium cells in the femur and tibia of adult rats following ESW treatment at two different energy flux densities. Four days after application of ESWs, there was a significant (3‐ to 6‐fold) increase in cambium layer thickness and cell number. Proliferation was seen with an energy flux density as low as 0.15 mJ/mm². The tibial cambium cells were more proliferative than those of the femur, with the cells closest to the ESW source proliferating the most. Within the thickened periosteum, α‐smooth muscle actin and von Willebrand Factor expression were upregulated, suggesting a vascular role in ESW osteogenesis. Bone formation was seen within the stimulated periosteum at day 4. We propose that non‐invasive ESWs can be used to rapidly stimulate cambium cell proliferation, providing a larger cell population for use as a progenitor cell source for tissue engineering applications, than can normally be provided by periosteum. © 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29: 1536–1543, 2011     

Behaviour of cancellous bone graft with and without periosteal isolation in striated muscle. An experimental study

The capacity of the periosteum to inhibit resorption of cancellous bone grafts into muscle was investigated in 34 four- to six-week-old rabbits. In 17 experiments the periosteum was wrapped around the grafts with the cambium layer facing the bone, and in seven experiments with the cambium layer facing the muscle. In the control group of 10 experiments there was no periosteal wrapping around the bone grafts. In Series 1 with the cambium layer of the periosteum facing the bone, after 20 weeks a tubular bone with Haversian system and bone marrow was seen. The transplants were surrounded by normal-looking periosteum. Bone formation from the periosteum occurred through enchondral ossification. Inductive bone growth was observed from the cancellous graft. In Series 2 with the cambium layer facing the surrounding muscle tissue, after 20 weeks two laminar bone blocks with periosteum in between and surrounding each block was observed. In the control series without periosteal covering, after 20 weeks only fibrous tissue remained in the transplantation site. It is obvious that periosteal isolation of cancellous bone grafts inhibits their resorption when transplanted into muscle in young animals.     

The chondrogenic potential of periosteum decreases with age.

Periosteum contains undifferentiated mesenchymal stem cells that possess the potential for chondrogenesis during cartilage repair and in fracture healing. With aging, the chondrogenic potential of periosteum declines significantly. An organ-culture model was used to investigate the relationship between the chondrogenic potential of periosteum and aging. A total of 736 periosteal explants from the proximal medial tibiae of 82 rabbits, aged 2 weeks to 2 years, were cultured in agarose suspension conditions conductive for chondrogenesis. and analyzed using histomorphometry, collagen typing, wet weight measurement, 3H-thymidine and 35S-sulfate uptake, autoradiography, and PCNA immunostaining. The rabbits were skeletally mature by 6 months and stopped increasing in weight by 12 months. Chondrogenesis declined significantly with age (P < 0.0001) and was maximal in the 1.5-2 month-old rabbits. Explants from the 6 month-old rabbits formed 50% less cartilage. and by 12 months chondrogenesis reached a steady state minimal level. In parallel with this decrease in chondrogenic potential similar decreases were measured in 3H-thymidine uptake (P < 0.0001). 35S-sulfate uptake (P = 0.0117), as well as the thickness (P < 0.0001) and the total number of cells in the cambium layer of the periosteum (P < 0.0001). Autoradiography with 3H-thymidine and PCNA immunostaining confirmed the measured decrease in proliferative activity in the cambium layer where the chondrocyte precursors reside, although the percentage of proliferating cells did not change significantly with age. The most dramatic change was the marked decrease (87%) in the thickness and total cell number in the cambium layer of the perisoteum between the 2 and 12 month-old rabbits (P < 0.05). These data confirm a decline in the chondrogenic potential of periosteum with aging. Thus, one possibility for improving cartilage formation by periosteal transplantation after skeletal maturity would be to stimulate an increase in the total number of cells in the chondrocyte precursor pool early during chondrogenesis.     

Periosteal augmentation of a tendon graft improves tendon healing in the bone tunnel

Secure fixation of tendon or ligament to bone has been a challenging problem. The periosteum is an osteogenic organ that regulates bone growth and remodeling at the outer surface of cortical bone and also is known to play an important role in forming a tendon insertion site to bone. Therefore, we hypothesized that a freshly harvested periosteum can be used as a stimulative scaffold to biologically reinforce the attachment of tendon graft to bone. Using a rabbit hallucis longus tendon and calcaneus process model, we found that a periosteal augmentation of a tendon graft could enhance the structural integrity of the tendon-bone interface, when the periosteum is placed between the tendon and bone interface with the cambium layer facing toward the bone. Clinically, the use of an autogenous periosteum patch would be an optimal choice for biologic augmentation of the tendon graft in the bone tunnel, because the tissue is readily available for harvest from the patient's body.     

Anatomical effects of periosteal elevation.

Research that involves harvesting the periosteum is common. The exact technique of harvesting is rarely described; however, it may be of vital importance because techniques may vary in their ability to raise the osteogenic cambial layer, which is reported to be tightly adherent to the underlying cortex. This study was performed to define how the cambial and fibrous layers of the periosteum are affected by different techniques of stripping. The periosteum was raised from the tibia and the humerus of adult rabbits with four stripping techniques. The stripped bone surface was examined histologically and with a scanning electron microscope to determine whether the fibrous and cambial layers of the periosteum had been removed and whether there had been damage to the underlying cortex. The results from the two anatomical sites were the same. Raising the periosteum with cortical bone chips (shingling) or with a periosteal elevator removed both layers of the periosteum and caused considerable damage to the surface of the cortex. Raising the periosteum with a sharp scalpel or by simply pulling it off removed the fibrous layer but left the osteogenic layer intact adherent to the cortex. We conclude that some techniques of periosteal elevation fail to harvest the osteogenic layer and therefore may lead to unexpected experimental results. We suggest that authors describe the exact technique of periosteal stripping that was employed.     

Periosteum responds to dynamic fluid pressure by proliferating in vitro.

Periosteum provides a source of undifferentiated chondrocyte precursor cells for fracture healing that can also be used for cartilage repair. The quantity of cartilage that can be produced, which is a determining factor in fracture healing and cartilage repair, is related to the number of available stem cells in the cambium layer. Cartilage formation during both of these processes is enhanced by motion of the fracture or joint in which periosteum has been transplanted. The effect of dynamic fluid pressure on cell proliferation in periosteal tissue cultures was determined in 452 explants from 60 immature (2-month-old) New Zealand White rabbits. The explants were cultured in agarose suspension for 1-14 days. One group was subjected to cyclic hydrostatic pressure, which is referred to as dynamic fluid pressure, at 13 kPa and a frequency of 0.3 Hz. Control explants were cultured in similar chambers without application of pressure. DNA synthesis ([3H]thymidine uptake) and total DNA were measured. The temporal pattern and distribution of cell proliferation in periosteum were evaluated with autoradiography and immunostaining with proliferating cell nuclear antigen. Dynamic fluid pressure increased proliferation of periosteal cells significantly, as indicated by a significant increase in [3H]thymidine uptake at all time points and a higher amount of total DNA compared with control values. On day 3, when DNA synthesis reached a peak in periosteal explants, [3H]thymidine uptake was 97,000+/-5,700 dpm/microg DNA in the group exposed to dynamic fluid pressure and 46,000+/-6,000 dpm/microg in the controls (p < 0.001). Aphidicolin, which blocks DNA polymerase alpha, inhibited [3H]thymidine uptake in a dose-dependent manner in the group subjected to dynamic fluid pressure as well as in the positive control (treated with 10 ng/ml of transforming growth factor-beta1) and negative control (no added growth factors) groups, confirming that [3H]thymidine measurements represent proliferation and dynamic fluid pressure stimulates DNA synthesis. Total DNA was also significantly higher in the group exposed to dynamic fluid pressure (5,700+/-720 ng/mg wet weight) than in the controls (3,700+/-630) on day 3 (p < 0.01). Autoradiographs with [3H]thymidine revealed that one or two cell cycles of proliferation took place in the fibrous layer prior to proliferation in the cambium layer (where chondrocyte precursors reside). Proliferating cell nuclear antigen immunophotomicrographs confirmed the increased proliferative activity due to dynamic fluid pressure. These findings suggest either a paracrine signaling mechanism between the cells in these two layers of the periosteum or recruitment/migration of proliferating cells from the fibrous to the cambium layer. On the basis of the data presented in this study, we postulate that cells in the fibrous layer respond initially to mechanical stimulation by releasing growth factors that induce undifferentiated cells in the cambium layer to divide and differentiate into chondrocytes. These data indicate that cell proliferation in the early stages of chondrogenesis is stimulated by mechanical factors. These findings are important because they provide a possible explanation for the increase in cartilage repair tissue seen in joints subjected to continuous passive motion. The model of in vitro periosteal chondrogenesis under dynamic fluid pressure is valuable for studying the mechanisms by which mechanical factors might be involved in the formation of cartilage in the early fracture callus and during cartilage repair.     

The cellular origin of cartilage-like tissue after periosteal transplantation of full-thickness articular cartilage defects: an experimental study using transgenic rats expressing green fluorescent protein

BACKGROUND: Periosteal transplantation is commonly used for the treatment of articular cartilage defects. However, the cellular origin of the regenerated tissue after periosteal transplantation has not been well defined. The objective of this study was to investigate the cellular origin of the regenerated tissue after periosteal transplantation. METHOD: Free periosteum was harvested from the tibia of 10-week-old adolescent enhanced green fluorescent protein (GFP-) expressing transgenic Sprague Dawley (SD) rats and was transplanted to full-thickness articular cartilage defects of the patellar groove in normal 10-week-old adolescent SD rats. The periosteum was sutured to the defect with the cambium layer facing the joint cavity. 8 SD rats were killed at 4 weeks and 8 SD rats were killed at 8 weeks after surgery. The repaired tissue was assessed histologically and histochemically. GFP-positive cells derived from the donor periosteum could easily be detected in the repaired tissue by use of a fluorescent microscope. RESULTS: At both 4 and 8 weeks after transplantation, the entire area of the defects had been repaired, with the regenerated tissue being well stained histologically with safranin-O. Most cells in the whole area of the regenerated tissue were GFP-positive, indicating that very few of the cells were GFP-negative cells originating from the recipient rats. INTERPRETATION: This experiment demonstrates that most cells in regenerated tissue after periosteal transplantation using adolescent animals do not originate from recipient cells but from the periosteal cells of the donor.     

Localization of chondrocyte precursors in periosteum

OBJECTIVE: Periosteal chondrogenesis is relevant to cartilage repair and fracture healing. Periosteum contains two distinct layers: a thick, outer fibrous layer and a thin, inner cambium layer which is adjacent to the bone. Specific chondrocyte precursors are known to exist in periosteum but have not yet been identified. In this study, the location of the chondrocyte precursors in periosteum was determined. METHOD: One hundred and twenty periosteal explants from 30 2-month-old NZ rabbits were cultured for up to 42 days. Histomorphological changes and spatio-temporal localization of Col. II mRNA and protein were analysed. RESULTS: On day 7, chondrocyte differentiation appeared in the most juxtaosseous region in the cambium layer. Col. II mRNA and protein were also evident in the same region. By day 14, chondrocyte differentiation progressed further into the juxtaosseous cambium layer, as did Col. II mRNA and protein. With growth of the neocartilage, the cambium layer gradually diminished to the extent that by 21-28 days it was no longer evident. Cartilage growth was significant and followed an appositional pattern, growing away from the fibrous layer. The fibrous layer remained essentially unchanged from 0-42 days, without evidence of hypertrophy or atrophy. Col. II mRNA expression was never seen in the fibrous layer. CONCLUSION: From these data, three conclusions can be drawn concerning chondrogenesis from periosteum: (1) the chondrocyte precursors are located in the cambium layer of periosteum; (2) chondrogenesis commences in the juxtaosseous area in the cambium layer and progresses from the juxtaosseous region to the juxtafibrous region of the cambium layer; (3) neocartilage growth is appositional, which displaces the fibrous layer away from the cartilage already formed, as new cartilage is formed between these two layers. These findings suggest that the least differentiated (stem or reserve) cells are located in the cambium layer furthest from the bone. CLINICAL RELEVANCE: These findings show that the chondrocyte precursors are located in the cambium layer of periosteum. Preservation of this layer is essential for chondrogenesis. As neocartilage growth is appositional, away from the fibrous layer, it can be expected that the new cartilage deposited in and adjacent to a periosteal graft would be expected to be located on the side of the cambium layer, rather than on the side of the fibrous layer of the graft.     

Relationship of donor site to chondrogenic potential of periosteum in vitro

Periosteum has been shown in vitro and in vivo to have a chondrogenic potential that permits it to be used for cartilage regeneration. A useful donor site should have good chondrogenic potential, availability of a large quantity of periosteum, and relative ease of access, and it should be associated with a low rate of morbidity. We hypothesized that the chondrogenic potential of periosteum varies from one bone to another and among different regions of the periosteum from a single bone. A total of 370 periosteal and 37 fascia lata (control) explants were taken from the skull, the ilium, the scapula, the upper, middle, and lower medial proximal tibia, the posterior proximal tibia, and the distal tibia of 2-month-old New Zealand rabbits. The explants were cultured for 6 weeks in agarose/Dulbecco's modified Eagle medium to which 10 ng/ml of transforming growth factor-β1 was added during the first 2 weeks. Skeletal muscle and fascia lata were used as controls. In addition, the thickness, cell density, and total cell count of the cambium layer were measured in 24 explants from the donor sites on the ilium and the upper, middle, and lower proximal tibia. At 6 weeks, histomorphometry and quantitative collagen typing were performed. The periosteal donor sites could be grouped into three categories according to chondrogenic potential: ilium (best), scapula and tibia, and skull (no chondrogenesis). The scapular periosteum was slightly better than that from the tibia. Within the tibia, the upper and middle zones of the proximal region were similar and were slightly better than the lower proximal tibia or the distal tibia. The cellularity of the cambium layer correlated positively with the amount of cartilage as a percentage of the total area. The results of this study indicate that iliac periosteum exhibited the best overall chondrogenic potential in vitro but that periosteum from the traditionally used medial proximal tibia also was excellent. Periosteum from the skull was not chondrogenic. The chondrogenic potential of periosteum varies from bone to bone and within the periosteum from one bone. This variation in chondrogenic potential among donor sites may be due to a difference in the total cell count of the cambium layer.     

The cellular origin of cartilage-like tissue after periosteal transplantation of full-thickness articular cartilage defects: An experimental study using transgenic rats expressing green fluorescent protein

Background?Periosteal transplantation is commonly used for the treatment of articular cartilage defects. However, the cellular origin of the regenerated tissue after periosteal transplantation has not been well defined. The objective of this study was to investigate the cellular origin of the regenerated tissue after periosteal transplantation.

Method?Free periosteum was harvested from the tibia of 10-week-old adolescent enhanced green fluorescent protein (GFP-) expressing transgenic Sprague Dawley (SD) rats and was transplanted to full-thickness articular cartilage defects of the patellar groove in normal 10-week-old adolescent SD rats. The periosteum was sutured to the defect with the cambium layer facing the joint cavity. 8 SD rats were killed at 4 weeks and 8 SD rats were killed at 8 weeks after surgery. The repaired tissue was assessed histologically and histochemically. GFP-positive cells derived from the donor periosteum could easily be detected in the repaired tissue by use of a fluorescent microscope.

Results?At both 4 and 8 weeks after transplantation, the entire area of the defects had been repaired, with the regenerated tissue being well stained histologically with safranin-O. Most cells in the whole area of the regenerated tissue were GFP-positive, indicating that very few of the cells were GFP-negative cells originating from the recipient rats.

Interpretation?This experiment demonstrates that most cells in regenerated tissue after periosteal transplantation using adolescent animals do not originate from recipient cells but from the periosteal cells of the donor.

?     

Human femoral neck has less cellular periosteum, and more mineralized periosteum, than femoral diaphyseal bone

Periosteal expansion enhances bone strength and is controlled by osteogenic cells of the periosteum. The extent of cellular periosteum at the human femoral neck, a clinically relevant site, is unclear. This study was designed to histologically evaluate the human femoral neck periosteal surface. Femoral neck samples from 11 male and female cadavers (ages 34-88) were histologically assessed and four periosteal surface classifications (cellular periosteum, mineralizing periosteum, cartilage, and mineralizing cartilage) were quantified. Femoral mid-diaphysis samples from the same cadavers were used as within-specimen controls. The femoral neck surface had significantly less (P<0.05) cellular periosteum (18.4+/-9.7%) compared to the femoral diaphysis (59.2+/-13.8%). A significant amount of the femoral neck surface was covered by mineralizing periosteal tissue (20-70%). These data may provide an alternate explanation for the apparent femoral neck periosteal expansion with age and suggest the efficiency of interventions that stimulate periosteal expansion may be reduced, albeit still possible, at the femoral neck of humans.     

A new fixation technique for metatarsal fractures.

Intramedullary nail fixation is an excellent option for open reduction and internal fixation of metatarsal neck and shaft fractures. In the authors' experience, the reduction of these fractures with Steinmann pin fixation provided excellent stability, required minimal soft-tissue dissection, and allowed for preservation of the periosteal tissue. Minimal disruption to the periosteum protects the osteoprogenitor cells located in the cambium layer. These cells stimulate osteoblastic activity, allowing for excellent secondary bone healing. Intramedullary nail fixation is the authors' chosen procedure for reduction of lesser metatarsal fractures.     

Clonal growth of human articular cartilage and the functional role of the periosteum in chondrogenesis

OBJECTIVE: Clinical cartilage repair with transplantation of cultured chondrocytes, the first described technique introduced in 1994, includes a periosteal membrane but today cells are also implanted without the periosteal combination. The aim of this study was to see if the periosteum had more than a biomechanical function and if the periosteum had a biological effect on the seeded cells tested in an agarose system in which the clonal growth in agarose and the external growth stimulation could be analysed. METHODS: Four different experiments were used to study the growth of human chondrocytes in agarose and the periosteal influence. Human chondrocytes were isolated and transferred to either primary or secondary agarose culture. After 4 weeks, the total number of clones >50 microm was counted. Cocultures of chondrocytes and periosteal tissue, cultures of chondrocytes with conditioned medium from chondrocytes, periosteal cells and fibroblast were used to study a potential stimulatory effect on growth and different cytokines and growth factors were analysed. RESULTS: It was found that the human chondrocytes had different growth properties in agarose with the formation of four different types of clones: a homogenous clone without matrix production, a homogenous clone with matrix production, a differentiated clone with matrix production and finally a differentiated clone without matrix production. The periosteum exerted a paracrine effect on cultured chondrocytes in agarose resulting in a higher degree of cloning. The chondrocytes produced significant amounts of interleukin (IL)-6, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor (TGF)-beta. The periosteum produced significant amounts of IL-6, IL-8 and TGF-beta. Cocultures of chondrocytes and periosteum demonstrated a potentiation of IL-6 and IL-8 release but not of TGF-beta and GM-CSF. CONCLUSION: Articular chondrocytes are able to form clones of different properties in agarose and the periosteum has a capacity of stimulating chondrocyte clonal growth and differentiation and secretes significant amounts of IL-6, IL-8, GM-CSF and TGF-beta. It may be that the repair of cartilage defects with seeded chondrocytes could benefit from the combination with a periosteal graft. The production of TGF-beta by implanted chondrocytes could influence the chondrogenic cells in the periosteum to start a periosteal chondrogenesis and together with the matrix from implanted chondrocyte production, a repair of cartilaginous appearance may develop; a dual chondrogenic response is possible.     

去除外骨膜对引导性骨再生模型成骨过程的影响

目的研究去除外骨膜对引导性骨再生成骨过程的影响。方法对２４只新西兰兔双侧桡骨制作１０ｍｍ骨缺损,一侧保留外骨膜并用硅胶管连接,另一侧于缺损两端各去除外骨膜１０ｍｍ,其余手术方法相同,动物分别于术后３天和１、２、３、４、６、１０、１２周处死,标本行Ｘ线、非脱钙骨切片组织学检查。结果（１）去除外骨膜后对于膜管内、膜管外成骨过程均无影响;（２）外骨膜生发层中的成骨细胞与哈弗系统中央管内及骨表面的成骨细胞相互联系;（３）外骨膜的两层结构分别来自于不同的组织：纤维层组织来自于外周的软组织,生发层中的成骨细胞来自于骨表面及哈弗系统。结论去除外骨膜对引导性骨再生模型的成骨过程无影响     

The periosteum. Part 1: Anatomy, histology and molecular biology

The periosteum is a thin layer of connective tissue that covers the outer surface of a bone in all places except at joints (which are protected by articular cartilage). As opposed to bone itself, it has nociceptive nerve endings, making it very sensitive to manipulation. It also provides nourishment in the form of blood supply to the bone. The periosteum is connected to the bone by strong collagenous fibres called Sharpey's fibres, which extend to the outer circumferential and interstitial lamellae of bone. The periosteum consists of an outer "fibrous layer" and inner "cambium layer". The fibrous layer contains fibroblasts while the cambium layer contains progenitor cells which develop into osteoblasts that are responsible for increasing bone width. After a bone fracture the progenitor cells develop into osteoblasts and chondroblasts which are essential to the healing process. This review discusses the anatomy, histology and molecular biology of the periosteum in detail.     

Differential phenotypic characteristics of heterogeneous cell population in the rabbit periosteum

BACKGROUND: Periosteum and periosteum-derived progenitor cells have demonstrated the potential for stimulative applications in repair of various musculoskeletal tissues. It has been found that the periosteum contains mesenchymal progenitor cells that are capable of differentiating into either osteoblasts or chondrocytes, depending on the culture conditions. Anatomically, the periosteum is a heterogeneous multilayered membrane, consisting of an outer fibrous and an inner cambium layer. The present study was designed to elucidate the phenotypic characteristics of fibrous and cambium layer cells in vitro. METHODS: Using a sequential enzymatic digestion method, fibrous and cambium layer cells were harvested separately from periosteum-bone explants of the proximal tibia of 6-month-old New Zealand White rabbits. RESULTS: We found that the cells from each layer showed distinct phenotypic characteristics in a primary monolayer culture system. Specifically, the cambium cells demonstrated higher osteogenic characteristics (higher alkaline phosphatase and osteocalcin levels) than the fibrous cells. However, these differences diminished with time in vitro. INTERPRETATION: Our findings suggest that the periosteum has phenotypically distinct heterogeneous cell populations. Care must be taken in order to identify and distinguish the intrinsic phenotypes of the heterogeneous periosteum-derived cell types in vitro.     

The Osteogenic Capacity of Free Periosteal and Osteoperiosteal Grafts: A Comparative Study in Growing Rabbits

The behaviour of free periosteal and 200 micron thick osteoperiosteal grafts was studied histologically in 40 six-week-old rabbits. The grafts were taken from the tibia and fixed on either side of the same lumbar vertebra between the spinous and mamillary processes. The free stripped periosteum had better osteogenic activity than the 200 micron thick osteoperiosteum. The new bone was formed by the osteogenic cells of the cambium layer in both types of graft.     

Uncovering the periosteum for skeletal regeneration: The stem cell that lies beneath

The cartilage- and bone-forming properties of the periosteum have long since been recognized. As one of the major sources of skeletal progenitor cells, the periosteum plays a crucial role not only in bone development and growth, but also during bone fracture healing. Aided by the continuous expansion of tools and techniques, we are now starting to acquire more insight into the specific role and regulation of periosteal cells. From a therapeutic point of view, the periosteum has attracted much attention as a cell source for bone tissue engineering purposes. This interest derives not only from the physiological role of the periosteum during bone repair, but is also supported by the unique properties and marked bone-forming potential of expanded periosteum-derived cells. We provide an overview of the current knowledge of periosteal cell biology, focusing on the cellular composition and molecular regulation of this remarkable tissue, as well as the application of periosteum-derived cells in regenerative medicine approaches. This article is part of a Special Issue entitled “Stem Cells and Bone”.     

The osteogenic capacity of free periosteal and osteoperiosteal grafts. A comparative study in growing rabbits.

The behaviour of free periosteal and 200 micron thick osteoperiosteal grafts was studied histologically in 40 six-week-old rabbits. The grafts were taken from the tibia and fixed on either side of the same lumbar vertebra between the spinous and mamillary processes. The free stripped periosteum had better osteogenic activity than the 200 micron thick osteoperiosteum. The new bone was formed by the osteogenic cells of the cambium layer in both types of graft.