Comparison of three surgical models of bone tissue defects in cleft palate in rabbits

The Use of Platelet Concentrates in the Reconstruction of the Alveolar Cleft Defect: A Systematic Review and Meta-Analysis

OBJECTIVE

Evaluate quantitative and qualitative outputs when comparing the incidence of platelet concentrates (PCs) combined with autogenous bone grafts to an autograft control group for the reconstruction of alveolar cleft defects.

DESIGN

Systematic review and meta-analysis.

PATIENTS/PARTICIPANTS

Randomized and nonrandomized controlled clinical trials where PCs were used in the reconstruction of alveolar cleft defects.

INTERVENTIONS

Use of PCs in combination with autogenous bone graft in the experimental group and autogenous bone graft alone in the control group.

MAIN OUTCOME MEASURE(S)

Average bone formation and bone density were evaluated, mean differences were calculated and pooled by a meta-analysis technique. Additionally, clinical outcomes such as wound dehiscence, closure of the oronasal fistula, pain, swelling, discharges, infections, and bleeding were considered in the qualitative synthesis.

RESULTS

After an evaluation of forty-nine articles, nineteen were considered for the review. The qualitative assessment of bone density, bone formation, and clinical outcomes showed no differences between groups in most of the included studies. The meta-analysis showed no statistical differences between PCs groups when compared to the control group in bone density at three months (mean difference 45.67 HU, P = .23) and six months (mean difference 48.57 HU, P = .64). Neither were statistical differences in the percentage of regenerated bone volume at six months (mean difference 6.39%, P = .15) and the volume of newly formed bone at 12 months (mean difference 0.37 mm3, P = .99).

CONCLUSIONS

There were no significant differences in terms of bone formation, bone density, and clinical outputs between groups.

Combining Bone Collagen Matrix with hUC-MSCs for Application to Alveolar Process Cleft in a Rabbit Model

BACKGROUND

Most materials used clinically for filling severe bone defects either cannot induce bone re-generation or exhibit low bone conversion, therefore, their therapeutic effects are limited. Human umbilical cord mesenchymal stem cells (hUC-MSCs) exhibit good osteoinduction. However, the mechanism by which combining a heterogeneous bone collagen matrix with hUC-MSCs to repair the bone defects of alveolar process clefts remains unclear.

METHODS

A rabbit alveolar process cleft model was established by removing the bone tissue from the left maxillary bone. Forty-eight young Japanese white rabbits (JWRs) were divided into normal, control, material and MSCs groups. An equal volume of a bone collagen matrix alone or combined with hUC-MSCs was implanted in the defect. X-ray, micro-focus computerized tomography (micro-CT), blood analysis, histochemical staining and TUNEL were used to detect the newly formed bone in the defect area at 3 and 6 months after the surgery.

RESULTS

The bone formation rate obtained from the skull tissue in MSCs group was significantly higher than that in control group at 3 months (P < 0.01) and 6 months (P < 0.05) after the surgery. The apoptosis rate in the MSCs group was significantly higher at 3 months after the surgery (P < 0.05) and lower at 6 months after the surgery (P < 0.01) than those in the normal group.

CONCLUSIONS

Combining bone collagen matrix with hUC-MSCs promoted the new bone regeneration in the rabbit alveolar process cleft model through promoting osteoblasts formations and chondrocyte growth, and inducing type I collagen formation and BMP-2 generation.

Repair of alveolar cleft bone defects in rabbits by active bone particles containing modified rhBMP-2

Objective: A model of alveolar cleft phenotype was established in rabbits to evaluate the effect of active bone particles containing modified rhecombinant human BMP-2 on the repair of the alveolar cleft. Methods: 2-month-old Japanese white rabbits were selected and randomly divided into four groups: normal, control, material and BMP groups. Blood biochemical analysis, skull tomography (microfocus computerized tomography), and histological and immunohistochemical staining analysis of paraffin sections were performed 3  and 6 months after operation. Results: Both types of collagen particles showed good biocompatibility and promoted bone regeneration. The effect of active bone particles on bone repair and regeneration was better than that of bone collagen particles. Conclusions: Active bone particles containing modified rhecombinant human BMP-2 can be used for incisors regeneration.

A new congenital cleft palate New Zealand rabbit model for surgical research

Cleft palate repair is a challenging procedure for cleft surgeons to teach, and in research, it can be difficult to evaluate different techniques and develop new treatments. In this study, a congenital cleft palate New Zealand rabbit model has been described and could be beneficial in future studies concerning cleft palate repair. Pregnant New Zealand rabbits received 1.0 mg dexamethasone injection intramuscularly once a day from the 13th gestation day (GD13) to GD16. On GD31. Newborn rabbits were delivered by cesarean sections, fed with a standardized gastric tube feeding method, and divided into two groups. The rate of survival and the incidence of cleft palate was calculated. Weight, appearance, behavior, maxillary occlusal view, and regional anatomic and histological comparisons were recorded within 1 month after birth. Infants from the two groups with similar physiological conditions were selected for continuous maxillofacial and mandibular Micro-CT scan and three-dimensional reconstruction analysis. Ten pregnant rabbits gave birth to 48 live infants. The survival and cleft palate rates were 65.6% and 60.4% respectively. Both groups survived over 1 month with no difference in weight, appearance, and behavior. The cleft type was stable, and anatomical defects, histological characteristics, and nasal-maxillary abnormalities of the cleft were similar to those of humans. There was no statistically significant difference in maxillary and mandible development between the two groups within one month after birth. This congenital cleft palate model is considered to have more research possibilities with efficient cleft induction, reliable feeding methods, stable anatomical defects, and maxillofacial development similar to those seen in humans.

Repair of alveolar cleft bone defects by bone collagen particles combined with human umbilical cord mesenchymal stem cells in rabbit

Background

Alveolar cleft is a type of cleft lip and palate that seriously affects the physical and mental health of patients. In this study, a model of the alveolar cleft phenotype was established in rabbits to evaluate the effect of bone collagen particles combined with human umbilical cord mesenchymal stem cells (HUC-MSCs) on the repair of alveolar cleft bone defects.

Methods

A model of alveolar clefts in rabbits was established by removing the incisors on the left side of the upper jaw bone collagen particles combined with HUC-MSCs that were then implanted in the defect area. Blood biochemical analysis was performed 3 months after surgery. Skull tissues were harvested for gross observation, and micro-focus computerised tomography (micro-CT) analysis. Tissues were harvested for histological and immunohistochemical staining. The experiments were repeated 6 months after surgery.

Results

Bone collagen particles and HUC-MSCs showed good biocompatibility. Bone collagen particles combined with HUC-MSCs were markedly better at inducing bone repair and regeneration than bone collagen particles alone.

Conclusions

Combining HUC-MSCs with bone collagen particles provides a simple, rapid and suitable method to fill a bone defect site and treat of alveolar cleft bone defects.

Functional Validation of a New Alginate-based Hydrogel Scaffold Combined with Mesenchymal Stem Cells in a Rat Hard Palate Cleft Model

Background:

One of the major difficulties in cleft palate repair is the requirement for several surgical procedures and autologous bone grafting to form a bony bridge across the cleft defect. Engineered tissue, composed of a biomaterial scaffold and multipotent stem cells, may be a useful alternative for minimizing the non-negligible risk of donor site morbidity. The present study was designed to confirm the healing and osteogenic properties of a novel alginate-based hydrogel in palate repair.

Methods:

Matrix constructs, seeded with allogeneic bone marrow–derived mesenchymal stem cells (BM-MSCs) or not, were incorporated into a surgically created, critical-sized cleft palate defect in the rat. Control with no scaffold was also tested. Bone formation was assessed using microcomputed tomography at weeks 2, 4, 8, and 12 and a histologic analysis at week 12.

Results:

At 12 weeks, the proportion of bone filling associated with the use of hydrogel scaffold alone did not differ significantly from the values observed in the scaffold-free experiment (61.01% ± 5.288% versus 36.91% ± 5.132%; p = 0.1620). The addition of BM-MSCs stimulated bone formation not only at the margin of the defect but also in the center of the implant.

Conclusions:

In a relevant in vivo model of cleft palate in the rat, we confirmed the alginate-based hydrogel’s biocompatibility and real advantages for tissue healing. Addition of BM-MSCs stimulated bone formation in the center of the implant, demonstrating the new biomaterial’s potential for use as a bone substitute grafting material for cleft palate repair.

Effects of phenytoin spray in prevention of fistula formation following cleft palate repair

BACKGROUND

The effectiveness of topical phenytoin has been reported for the treatment of oral biopsy ulcers, chemotherapy-induced oral mucositis, and chronic periodontitis. This study aimed to investigate the effects of topical phenytoin 2% on the prevention of fistula formation after cleft palate repair.

METHOD

This randomized clinical trial studied patients with nonsyndromic cleft palate who were referred to a tertiary center and underwent cleft palate repair from March 2010 to February 2015. Patients in the phenytoin group received phenytoin spray 2% for 8 weeks and were compared with an age- and sex-matched control group.

RESULTS

A total of 160 patients in two phenytoin and control groups (n = 80 for each group) were recruited to the study. The mean ages of patients in the phenytoin and control groups were 11.42 ± 1.30 and 11.08 ± 1.25 months, respectively. The results showed that six patients (7.5%) in the phenytoin group and 15 patients (18.8%) in the control group formed fistulas during the 6-month follow-up period. There was a significant difference in fistula formation between the phenytoin and control groups (p = 0.035). Furthermore, fistula size was significantly smaller in the phenytoin group compared with the control group (p < 0.001).

CONCLUSION

More frequent use of phenytoin spray can be considered, although there is insufficient information on the long-term side-effects of the chosen drug.