Histologic and biochemical analysis of osteogenic capacity of vascularized periosteum

Reg Gene Expression in Periosteum after Fracture and Its In Vitro Induction Triggered by IL-6

The periosteum is a thin membrane that surrounds the outer surface of bones and participates in fracture healing. However, the molecular signals that trigger/initiate the periosteal reaction are not well established. We fractured the rat femoral bone at the diaphysis and fixed it with an intramedullary inserted wire, and the expression of regenerating gene (Reg) I, which encodes a tissue regeneration/growth factor, was analyzed. Neither bone/marrow nor muscle showed RegI gene expression before or after the fracture. By contrast, the periosteum showed an elevated expression after the fracture, thereby confirming the localization of Reg I expression exclusively in the periosteum around the fractured areas. Expression of the Reg family increased after the fracture, followed by a decrease to basal levels by six weeks, when the fracture had almost healed. In vitro cultures of periosteal cells showed no Reg I expression, but the addition of IL-6 significantly induced Reg I gene expression. The addition of IL-6 also increased the cell number and reduced pro-apoptotic gene expression of Bim. The increased cell proliferation and reduction in Bim gene expression were abolished by transfection with Reg I siRNA, indicating that these IL-6-dependent effects require the Reg I gene expression. These results indicate the involvement of the IL-6/Reg pathway in the osteogenic response of the periosteum, which leads to fracture repair.

Efficacy of Connective Tissue with and without Periosteum in Regeneration of Intrabony Defects

Background and aims. Connective tissue grafts with and without periosteum is used in regenerative treatments of bone and has demonstrated successful outcomes in previous investigations. The aim of present study was to evaluate the effectiveness of connective tissue graft with and without periosteum in regeneration of intrabony defects.

Materials and methods. In this single-blind randomized split-mouth clinical trial, 15 pairs of intrabony defects in 15 patients with moderate to advanced periodontitis were treated by periosteal connective tissue graft + ABBM (test group) or non-periosteal connective tissue graft + ABBM (control group). Probing pocket depth, clinical attachment level, free gingival margin position, bone crestal position, crest defect depth and defect depth to stent were measured at baseline and after six months by surgical re-entry. Data was analyzed by Student’s t-test and paired t-tests (α=0.05).

Results. Changes in clinical parameters after 6 months in the test and control groups were as follows: mean of PPD reduction: 3.1±0.6 (P<0.0001); 2.5±1.0 mm (P<0.0001), CAL gain: 2.3±0.9 (P<0.0001); 2.2±1.0 mm (P<0.0001), bone fill: 2.2±0.7 mm (P<0.0001); 2.2±0.7 mm (P<0.0001), respectively. No significant differences in the position of free gingival margin were observed during 6 months compared to baseline in both groups.

Conclusion. Combinations of periosteal connective tissue graft + ABBM and non-periosteal connective tissue graft + ABBM were similarly effective in treating intrabony defects without any favor for any group. Connective tissue and perio-steum can be equally effective in regeneration of intrabony defects.

Connective tissue graft as a biological barrier for guided tissue regeneration in intrabony defects: a histological study in dogs

BACKGROUND

The use of the autogenous periosteal graft as biological barrier has been proposed for periodontal regeneration. The aim of this study was to evaluate the histometric findings of the subepithelial connective tissue graft as barrier in intrabony defects compared to a bioabsorbable membrane.

METHODS

Three-walled intrabony defects were created surgically in the mesial aspect of the right and left maxillary canines in five healthy mongrel dogs. The defects were chronified, and two types of barriers were randomly carried out for guided tissue regeneration in a split-mouth design: the test group with a subepithelial connective tissue graft and the control group with a bioabsorbable membrane. The specimens were processed for histometric analyses of the epithelium (E), connective tissue (CT), newly formed cementum (NC), new bone (NB), and total newly formed tissues (NFT).

RESULTS

The test side showed smaller mean of NC (3.6 ± 1.2), NB (2.1 ± 0.7), and NFT (7.7 ± 0.8) than the control group (NC 7.3 ± 0.5; NB 5.3 ± 1.3; NFT 10.1 ± 2.2; P < 0.05). No statistically significant differences were verified for E (test 3.1 ± 2.0; control 2.8 ± 2.1; P > 0.05) and CT (test 2.5 ± 1.1; control 2.0 ± 0.5; P > 0.05) between groups.

CONCLUSION

The bioabsorbable membrane was more effective in maintaining the space for periodontal regeneration than periosteal connective graft when used as barrier.

CLINICAL RELEVANCE

The bioabsorbable membrane showed more favorable regenerative results in intrabony defects in dogs than the subepithelial connective tissue graft as biological barrier.

Comparative evaluation of periosteum as a barrier membrane with and without an alloplastic bone graft in periodontal osseous defects: A 9 months follow-up study

BACKGROUND

Regenerative procedures frequently include the use of barrier membranes and bone grafting materials to encourage the growth of key surrounding tissues. The present study aims to evaluate and compare the ability of periosteum in intrabony defect regeneration.

MATERIALS AND METHODS

A total of ten intrabony defects were equally divided in two treatment groups. Group I consisted of Periosteum used as a barrier memebrane and Group II of periosteum as barrier membrane alongwith graft material. Nine months post operative evaluation of defect fill was done radiographically.

RESULTS

Mean defect fill (CEJ-BBD) was found to be significantly lower in Group II as compared to Group I (P = 0.041).

CONCLUSION

Within the limitations of this study, alloplastic graft material supplimentation results in better regeneration with Periosteum used as a barrier membrane.

Microsurgical techniques used to construct the vascularized and neurotized tissue engineered bone

The lack of vascularization in the tissue engineered bone results in poor survival and ossification. Tissue engineered bone can be wrapped in the soft tissue flaps which are rich in blood supply to complete the vascularization in vivo by microsurgical technique, and the surface of the bone graft can be invaded with new vascular network. The intrinsic vascularization can be induced via a blood vessel or an arteriovenous loop located centrally in the bone graft by microsurgical technique. The peripheral nerve especially peptidergic nerve has effect on the bone regeneration. The peptidergic nerve can be used to construct the neurotized tissue engineered bone by implanting the nerve fiber into the center of bone graft. Thus, constructing a highly vascularized and neurotized tissue engineered bone according with the theory of biomimetics has become a useful method for repairing the large bone defect. Many researchers have used the microsurgical techniques to enhance the vascularization and neurotization of tissue engineered bone and to get a better osteogenesis effect. This review aims to summarize the microsurgical techniques mostly used to construct the vascularized and neurotized tissue engineered bone.

Role of space provision in regeneration of localized two-wall intrabony defects using periosteal pedicle graft as an autogenous guided tissue membrane

BACKGROUND

Marginal pedicle periosteum (MPP) has been used as a rigid membrane in guided tissue regeneration (GTR) for osseous defects. The present study aims to study the effect of space provision by an alloplastic graft material in bone defect area (BDA) reduction of 2-wall defects.

METHODS

Twenty interproximal intrabony 2-wall defects in healthy non-smoking patients with chronic periodontitis were randomly divided in control (group 1, periosteum alone) and experimental (group 2, periosteum with alloplastic graft material) groups. Measurements of probing depth (PD), clinical attachment level (CAL), and radiographic BDA were done at the baseline and 6-month postoperative evaluations.

RESULTS

The 6-month postoperative assessment showed clinical and radiographic improvements with PD reduction, CAL gain, and changes in BDA in both groups, which was statistically significant compared with baseline (P <0.05). However, BDA reduction was statistically greater in group 2 (48.88% ± 18.61%) compared with group 1 (14.08% ± 12.97%) at the 6-month follow-up (P = 0.009).

CONCLUSION

Within the limitations of this study, it can be concluded that space provision by an alloplastic graft material increases the regenerative potential of MPP as a GTR membrane and results in increased defect fill.

The use of a vascularised periosteal patch onlay graft in the management of nonunion of the proximal scaphoid

We describe the use of a vascularised periosteal patch onlay graft based on the 1,2 intercompartmental supraretinacular artery in the management of 11 patients (ten men, one woman) with chronic nonunion involving the proximal third of the scaphoid. The mean age of the patients was 31 years (21 to 45) with the dominant hand affected in eight. Six of the patients were smokers and three had undergone previous surgery to the scaphoid. All of the proximal fragments were avascular. The presence of union was assessed using longitudinal axis CT.

Only three patients progressed to union of the scaphoid and four required a salvage operation for a symptomatic nonunion. The remaining four patients with a persistent nonunion are asymptomatic with low pain scores, good grip strength and a functional range of wrist movement.

Although this technique has potential technical advantages over vascularised pedicled bone grafting, the rate of union has been disappointing and we do not recommend it as a method of treatment.

Osteogenic capacities of tibial and cranial periosteum: a biochemical and histologic study

The periosteum has an important role in bone regeneration. The purpose of this study was to evaluate and compare the osteogenic capacities of tibial and cranial periosteum. To achieve this, 44 New Zealand male rabbits were divided into two groups, each consisting of 22 rabbits. In group 1, periosteal flaps were prepared on the tibia of the posterior cruris of each side. In group 2, bilateral periosteal flaps were prepared on the cranial region. New bone formation was estimated quantitatively by measuring the alkaline phosphatase and osteocalcin levels, because they are the indicators of osteoblastic activity. At weeks 1, 2, 4, and 8, biopsies were taken from five animals of each group for biochemical analyses, and at weeks 2 and 8, biopsies were taken for histologic evaluation. Higher alkaline phosphatase and osteocalcin levels were evaluated in group 1, and more bone formation was observed in group 1. The results showed that osteogenic capacity is higher in tibial periosteum than cranial periosteum.

The management of ununited fractures of the femoral neck using internal fixation and muscle pedicle periosteal grafting

We describe a series of 20 patients with ununited fractures of the femoral neck following neglected trauma or failed primary internal fixation who were seen at a mean of 7.5 months (2 to 18) following injury. Open reduction and internal fixation of the fracture was performed in all patients, together with a myoperiosteal flap on the quadratus femoris muscle pedicle. Union occurred at a mean of 4.9 months (2 to 10) in all patients. The mean follow-up was for 70 months (14 to 144). There was no further progression in six of seven patients with pre-operative radiological evidence of osteonecrosis of the femoral head. One patient had delayed collapse and flattening of the femoral head ten years after union of the fracture, but remained asymptomatic. This study demonstrates the orthopaedic application of myoperiosteal grafting for inducing osteogenesis in a difficult clinical situation.

Biological Assessment of Porous-Implant Hydroxyapatite Combined With Periosteal Grafting in Maxillary Defects

PURPOSE

To investigate the use of porous hydroxyapatite (HA) combined with periosteal graft to repair an induced maxillary bone defect.

MATERIALS AND METHODS

A defect was produced in the premaxillary bone of rats. Four groups were used: 1) those treated with the mucoperiosteal graft from the premaxilla; 2) those treated with HA combined with mucoperiosteal graft from the premaxilla; 3) those treated with HA combined with periosteal graft from the femur; and 4) those treated with periosteal graft from the femur.

RESULTS

The radiographic aspects from all groups showed no signs of bone formation after 2 weeks. After 16 weeks, there was evidence of points of radiolucency inside the HA implants. Cell proliferation occurred from the periosteum covering the defect. Bone tissue grew from the defect margin to inside the defect in all cases. Mature bone was seen around the HA implants after 8 and 16 weeks.

CONCLUSION

The periosteal graft provides satisfactory support to the HA implant, allowing the growth of new bone.

Regenerative Repair of Long Intercalated Rib Defects Using Porous Cylinders of ??-Tricalcium Phosphate: An Experimental Study in a Canine Model

BACKGROUND

In maxillofacial, spinal, and orthopedic surgery, bony ribs have been used as a source of donor bone. The resultant defects are not usually repaired, despite the pain or cosmetic morbidity experienced by the patient. The authors evaluated the efficacy of an osteoconductive beta-tricalcium phosphate and the contribution of the periosteum in rib bone regeneration.

METHODS

Two 8-cm-long intercalated rib defects were generated in each of 30 beagle dogs. In the first group (n = 15), one defect was implanted with 16 small, short, porous beta-tricalcium phosphate cylinders that were connected with a titanium wire, and the other defect was left untreated. In the remaining 15 dogs, the periosteum was devitalized by ethanol, and then the same surgical procedures were performed. Each group was subdivided into three groups (n = 5), and the animals were euthanized at 3, 6, and 12 weeks. Bone regeneration was assessed radiologically, histologically, and mechanically.

RESULTS

In the defect implanted with beta-tricalcium phosphate on intact periosteum, newly formed bone was present on and in the beta-tricalcium phosphate cylinders and bridged both ends of the resected ribs at 12 weeks, with replacement of beta-tricalcium phosphate by new bone. Mechanical testing of these ribs revealed that they had 70 percent of the strength of normal ribs when compared in a bending stress test at 12 weeks after surgery. No regenerative bone bridging the rib defects was seen in the ethanol-devitalized or untreated groups.

CONCLUSIONS

Porous beta-tricalcium phosphate cylinders placed in tandem on the intact periosteum might be useful for the repair of rib bone donated at surgery, presenting a new and unique method for regenerating rib defects.

Composite reconstruction in advanced cancer of the mouth floor: autogenous frozen-thawed mandibular bone and free flaps

Mandibular symphyseal resection requires composite reconstructions, often with unsatisfactory morphofunctional results. Seven patients with advanced squamous cell carcinoma of the floor of the mouth underwent block resection with immediate reconstruction, using the removed mandible treated with liquid nitrogen and covered with a free forearm flap. In all cases, the resection was radical and no major postoperative complications occurred. Two patients died in 6 months for distant metastases and regional recurrence. In the other 5 patients, no local recurrence occurred at a mean follow-up of 52 months (36-70). Immediate cosmetic and functional results were good. Of the 5 patients, 4 had late complications requiring further surgery. This technique of bone reimplantation produces no donor site morbidity, perfect immediate morphological result, and is of low cost. The free forearm flap is effective in sealing the oral cavity, though further clinical and experimental studies are necessary to reduce late local complications.

Healing response of apicomarginal defects to two guided tissue regeneration techniques in periradicular surgery: a double-blind, randomized-clinical trial

AIM

To compare healing responses to periosteal sliding grafts and polyglactin 910 periodontal mesh used as guided tissue regeneration (GTR) materials/techniques when both periapical and periradicular bone loss are present.

METHODOLOGY

Thirty patients with suppurative chronic apical periodontitis with apicomarginal communication were selected and allocated randomly into two groups according to the barrier technique to be used during periradicular surgery: periosteal graft group (n = 15) and bioabsorbable membrane group (n = 15). Clinical and radiological evaluations were completed prior to surgery, a week later and every 3 months after surgery up to 12 months to measure the periodontal pocket depth (PD), clinical attachment level (CAL), gingival margin position (GMP), size of periapical lesion, percentage reduction of the periapical rarefaction, and periapical healing.

RESULTS

Both groups showed highly significant (P < 0.001) reductions in periodontal PD, CAL and size of periapical lesion at 12 months whilst GMP was unaltered. No significant difference between the experimental groups was evident for these parameters, or for the percentage reduction of size of the periapical lesion and clinical-radiographic healing.

CONCLUSION

Guided tissue regeneration applied to apicomarginal defects using sliding periosteal grafts and use of bioabsorbable membranes led to similar enhancements of the clinical outcome of periradicular surgery in terms of periapical healing, gain of periodontal support, PD reduction and minimal recession of the gingival margin.

Experimental Study of Vascularized Tissue-Engineered Bone Grafts

BACKGROUND

Vascularized bone grafting has become a useful method for treatment of large bone defects and infected nonunions that lack adequate blood supply. This method has disadvantages, however, such as donor-site complications. To overcome these disadvantages, the authors developed a new method for creating vascularized tissue-engineered bone grafts in an experimental model.

METHODS

Fisher rat bone marrow mesenchymal stem cells were cultured for 2 weeks in fully opened, interconnected, porous hydroxyapatite ceramic. The composites of mesenchymal stem cells and hydroxyapatite were implanted in the medial calf region together with the saphenous vascular bundle in syngeneic rats. Two weeks after implantation, the vascular pedicle with the implants was exposed and covered with silicone rubber to prevent vascular invasion through surrounding tissues (vascularized mesenchymal stem cell/hydroxyapatite implants). In addition, nonvascularized mesenchymal stem cell/hydroxyapatite implants were created with a ligated vascular pedicle. Implants of vascularized hydroxyapatite alone were prepared as a control. All implants were retrieved 4 weeks after surgery.

RESULTS

Histologically, de novo bone formations were observed in the vascularized implants. This was in contrast with only necrotic tissue observed in the nonvascularized implants. Bone formation was not observed entirely in the vascularized hydroxyapatite-alone implants. For biochemical analysis, alkaline phosphatase activity and osteocalcin content of the vascularized mesenchymal stem cell/hydroxyapatite implants were significantly higher than those of the nonvascularized mesenchymal stem cell/hydroxyapatite and vascularized hydroxyapatite-alone implants.

CONCLUSION

The results of this study indicated that the vascularized tissue-engineered bone grafts could be transferred as free vascularized grafts to lesions that lack adequate blood supply.

Periosteal grafts as barriers in periradicular surgery: report of two cases

AIM

To describe the usefulness of periosteal grafts as barriers for bone regeneration in periradicular surgery when advanced periodontal breakdown occurs.

SUMMARY

The treatment of advanced periodontal breakdown as a result of an associated endodontic lesion constitutes a multifaceted challenge to the clinician. If the source of the irritation cannot be removed by orthograde endodontic treatment, nonsurgical and surgical endodontic/periodontal intervention may be required. Two cases with suppurative chronic apical periodontitis with apicomarginal communication are described. Clinical and radiological evaluations were completed immediately prior to surgery, a week later and every 2 months after surgery for 10 months. Both patients were treated using split-thickness flaps and lateral displacement of the periosteum prior to suturing, in order to close the communication between the oral and the periapical surroundings. A remission of the clinical signs and symptoms, and successful healing in the short-term were achieved in these cases.

KEY LEARNING POINTS

Periapical and periodontal lesions are closely related through pathways of communication. Disruption of the cortical plate and the presence of dentoalveolar sinus tracts can have a deleterious effect on the regeneration process after periradicular surgery. The adoption of supplementary periodontal surgical techniques may help to solve some of the difficulties in the healing process in periradicular surgery. Periosteal grafts have been shown to have the potential to stimulate bone formation when used as a graft material.

Comparing the Osteogenic Capacities of Bone Substitutes: Hydroxyapatite, High-Density Porous Polyethylene, and Bone Collagen: A Biochemical and Histological Analysis

Several inorganic materials have been shown previously to hold some osteogenic capacity. The purpose of this study is to compare the bone-forming abilities of hydroxyapatite ceramic, high-density porous polyethylene, and bone collagen within the periosteal island flap of rabbit tibia using histological and biochemical analysis. With this goal, four discrete experimental groups were formed, each comprising 22 New Zealand male rabbits. A sac was created on each rabbit tibial periosteum flap in each of the groups, and each of the previously mentioned materials was placed within this sac separately. One of these groups was thought as a control group without any material being placed inside the periosteal sac. Biopsies were taken at weeks 1, 2, 4, and 8 for biochemical analysis and at weeks 2 and 8 for histological evaluation. Neo-osteogenesis was evaluated quantitatively by determination of alkaline phosphatase and osteocalcin levels biochemically as well as by the percentage of new bone formation inside the periosteal sac histologically. Results show statistically that the osteogenic effect of high-density porous polyethylene is greater than that of the other materials used in this study (P < 0.05).

The role of beta-tricalcium phosphate in vascularized periosteum

To investigate the osteogenic capacity of vascularized periosteum in bore grafting, we prepared experimental groups by wrapping beta-tricalcium phosphate (beta-TCP) with vascularized periosteum of the femur of 12-week-old Japanese white rabbits, and evaluated osteogenesis histologically and biochemically. Bone formation was observed in the group with vascularized periosteum and in the group with bone marrow fluid added to the vascularized periosteum. In particular, woven bone was observed in the group that had added bone marrow. Osteogenesis appeared earlier in the group with bone marrow fluid added to the vascularized periosteum, but histologically, there was no significant difference between this group and the group with vascularized periosteum without bone marrow fluid added at week 24 after the operation. In the group with non-vascularized periosteum, slight osteogenesis was found at week 6 after the operation, but in the control group, with beta-TCP implanted in soft tissue, osteogenesis did not occur at all. Alkaline phosphatase (ALP) activity reached a peak at week 2 after the operation in the group with vascularized periosteum, but only half the peak value was then maintained until week 8. In the group with bone marrow fluid added to the vascularized periosteum, similar values were found from immediately after the operation until week 8. ALP activity did not show any significant difference between these two groups at week 8 postoperatively. In the group with beta-TCP implanted in the soft tissue, ALP activity was low at all times measured. These results suggested that the periosteum had osteoinduction capacity and beta-TCP had osteoconduction capacity; that better osteogenesis occurred with vascularized periosteum; and that bone marrow fluid was involved in the promotion of osteoblastic activity, but not in calcification.

Experimental use of fibrin glue to induce site-directed osteogenesis from cultured periosteal cells

The purpose of this study was to determine whether a combination of fibrin glue and cultured periosteal cells will result in new bone formation at heterotopic sites in nude mice. Growing cells and developing matrices surrounding periosteal explants from the diaphyses of radii of newborn calves were minced and mixed with fibrin glue in a syringe. The cell/matrix-fibrin glue admixture was then injected into the subcutaneous space on the dorsum of athymic nude mice. After 12 weeks of implantation, gross morphology and histologic investigations showed newly formed bone structures in all cell/matrix-fibrin glue admixtures, but none in fibrin glue injected alone and used as control samples. Osteopontin, a protein important in bone development, was identified by a Western blot assay of the cell/matrix-fibrin glue composite. This study supports the feasibility of initiating site-directed formation of bone structures at heterotopic tissue sites by means of injection of cultured periosteal cells and matrix in a fibrin glue carrier.

Formation of phalanges and small joints by tissue-engineering

BACKGROUND

This report describes the formation of small phalanges and whole joints from three types of bovine-cell sources transplanted onto biodegradable polymer matrices. The resulting structures had the shape and composition of human phalanges with joints.

METHODS

Fresh bovine periosteum was wrapped around a copolymer of polyglycolic and poly-L-lactic acid. Separate sheets of polyglycolic acid polymer were then seeded with chondrocytes and tenocytes isolated from the shoulders of freshly killed calves. The gross form of a composite tissue structure was constituted in vitro by assembling the parts and suturing them to create models of a distal phalanx, a middle phalanx, and a distal interphalangeal joint.

RESULTS

Subcutaneous implantation of the sutured composite tissues into athymic mice resulted in the formation, after twenty weeks, of new tissue with the shape and dimensions of human phalanges with joints. Histological examination revealed mature articular cartilage and subchondral bone with a tenocapsule that had a structure similar to that of human phalanges and joints. There was continuous cell differentiation at the ectopic site even after extended periods.

CONCLUSIONS

These findings suggest that the formation of phalanges and small joints is possible with the selective placement of periosteum, chondrocytes, and tenocytes into a biodegradable synthetic polymer scaffold.