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Engraftment of Prevascularized, Tissue Engineered Constructs in a Novel Rabbit Segmental Bone Defect Model.

Kaempfen A, Todorov A, Güven S, Largo RD, Jaquiéry C, Scherberich A, Martin I, Schaefer DJ - Int J Mol Sci (2015)

Bottom Line: Instead, a variable amount of necrotic tissue formed.Although necrotic area correlated significantly with amount of vessels and the 2-step strategy had significantly more vessels than the 1-step strategy, no significant reduction of necrotic area was found.In conclusion, the animal model developed here represents a highly challenging situation, for which a suitable engineered bone graft with better prevascularization, better resorbability and higher osteogenicity has yet to be developed.

View Article: PubMed Central - PubMed

Affiliation: Clinic for Plastic, Reconstructive, Aesthetic and Hand Surgery, University Hospital Basel, 4031 Basel, Switzerland. alexander.kaempfen@usb.ch.

ABSTRACT
The gold standard treatment of large segmental bone defects is autologous bone transfer, which suffers from low availability and additional morbidity. Tissue engineered bone able to engraft orthotopically and a suitable animal model for pre-clinical testing are direly needed. This study aimed to evaluate engraftment of tissue-engineered bone with different prevascularization strategies in a novel segmental defect model in the rabbit humerus. Decellularized bone matrix (Tutobone) seeded with bone marrow mesenchymal stromal cells was used directly orthotopically or combined with a vessel and inserted immediately (1-step) or only after six weeks of subcutaneous "incubation" (2-step). After 12 weeks, histological and radiological assessment was performed. Variable callus formation was observed. No bone formation or remodeling of the graft through TRAP positive osteoclasts could be detected. Instead, a variable amount of necrotic tissue formed. Although necrotic area correlated significantly with amount of vessels and the 2-step strategy had significantly more vessels than the 1-step strategy, no significant reduction of necrotic area was found. In conclusion, the animal model developed here represents a highly challenging situation, for which a suitable engineered bone graft with better prevascularization, better resorbability and higher osteogenicity has yet to be developed.

No MeSH data available.


Related in: MedlinePlus

(A) Analysis of necrotic core formation based on hematoxylin and eosin (H&E) staining. Blue rectangle indicates the total area considered during quantification. Black dotted outline is an example of necrotic area. Black bar represents 1 mm; (B) Necrotic area observed in the experimental groups, represented as fold of the average necrotic area in the pedicle 2-step group; (C) Representative Goldner Trichrome staining with vessels appearing red in high magnification. Black bar represents 50 mm; (D) Average vessel number inside the scaffold (blue rectangle in A), counted by Goldner Tichrome staining. Significant difference is marked by *; (E) Correlation of vessel number and necrotic area for each sample. Black line represents linear regression fit and dotted lines represent 95% confidence intervals.
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ijms-16-12616-f004: (A) Analysis of necrotic core formation based on hematoxylin and eosin (H&E) staining. Blue rectangle indicates the total area considered during quantification. Black dotted outline is an example of necrotic area. Black bar represents 1 mm; (B) Necrotic area observed in the experimental groups, represented as fold of the average necrotic area in the pedicle 2-step group; (C) Representative Goldner Trichrome staining with vessels appearing red in high magnification. Black bar represents 50 mm; (D) Average vessel number inside the scaffold (blue rectangle in A), counted by Goldner Tichrome staining. Significant difference is marked by *; (E) Correlation of vessel number and necrotic area for each sample. Black line represents linear regression fit and dotted lines represent 95% confidence intervals.

Mentions: Histological analysis did not demonstrate new bone formation inside the scaffold. Instead there was a variable amount of cell and tissue necrosis (Figure 4A). Although not significant, there was a trend towards less necrosis in the pedicle 2-step group (Figure 4B). A quantification of the density of blood vessels showed that the 2-step group had significantly (p = 0.043) more vessel sections than the 1-step group (Figure 4C,D). The difference between the pedicle 2-step group and the direct group was not significant. We found a significant inverse correlation (R2 = 0.677, p = 0.012) between the necrotic area and the density of blood vessels (Figure 4E).


Engraftment of Prevascularized, Tissue Engineered Constructs in a Novel Rabbit Segmental Bone Defect Model.

Kaempfen A, Todorov A, Güven S, Largo RD, Jaquiéry C, Scherberich A, Martin I, Schaefer DJ - Int J Mol Sci (2015)

(A) Analysis of necrotic core formation based on hematoxylin and eosin (H&E) staining. Blue rectangle indicates the total area considered during quantification. Black dotted outline is an example of necrotic area. Black bar represents 1 mm; (B) Necrotic area observed in the experimental groups, represented as fold of the average necrotic area in the pedicle 2-step group; (C) Representative Goldner Trichrome staining with vessels appearing red in high magnification. Black bar represents 50 mm; (D) Average vessel number inside the scaffold (blue rectangle in A), counted by Goldner Tichrome staining. Significant difference is marked by *; (E) Correlation of vessel number and necrotic area for each sample. Black line represents linear regression fit and dotted lines represent 95% confidence intervals.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490464&req=5

ijms-16-12616-f004: (A) Analysis of necrotic core formation based on hematoxylin and eosin (H&E) staining. Blue rectangle indicates the total area considered during quantification. Black dotted outline is an example of necrotic area. Black bar represents 1 mm; (B) Necrotic area observed in the experimental groups, represented as fold of the average necrotic area in the pedicle 2-step group; (C) Representative Goldner Trichrome staining with vessels appearing red in high magnification. Black bar represents 50 mm; (D) Average vessel number inside the scaffold (blue rectangle in A), counted by Goldner Tichrome staining. Significant difference is marked by *; (E) Correlation of vessel number and necrotic area for each sample. Black line represents linear regression fit and dotted lines represent 95% confidence intervals.
Mentions: Histological analysis did not demonstrate new bone formation inside the scaffold. Instead there was a variable amount of cell and tissue necrosis (Figure 4A). Although not significant, there was a trend towards less necrosis in the pedicle 2-step group (Figure 4B). A quantification of the density of blood vessels showed that the 2-step group had significantly (p = 0.043) more vessel sections than the 1-step group (Figure 4C,D). The difference between the pedicle 2-step group and the direct group was not significant. We found a significant inverse correlation (R2 = 0.677, p = 0.012) between the necrotic area and the density of blood vessels (Figure 4E).

Bottom Line: Instead, a variable amount of necrotic tissue formed.Although necrotic area correlated significantly with amount of vessels and the 2-step strategy had significantly more vessels than the 1-step strategy, no significant reduction of necrotic area was found.In conclusion, the animal model developed here represents a highly challenging situation, for which a suitable engineered bone graft with better prevascularization, better resorbability and higher osteogenicity has yet to be developed.

View Article: PubMed Central - PubMed

Affiliation: Clinic for Plastic, Reconstructive, Aesthetic and Hand Surgery, University Hospital Basel, 4031 Basel, Switzerland. alexander.kaempfen@usb.ch.

ABSTRACT
The gold standard treatment of large segmental bone defects is autologous bone transfer, which suffers from low availability and additional morbidity. Tissue engineered bone able to engraft orthotopically and a suitable animal model for pre-clinical testing are direly needed. This study aimed to evaluate engraftment of tissue-engineered bone with different prevascularization strategies in a novel segmental defect model in the rabbit humerus. Decellularized bone matrix (Tutobone) seeded with bone marrow mesenchymal stromal cells was used directly orthotopically or combined with a vessel and inserted immediately (1-step) or only after six weeks of subcutaneous "incubation" (2-step). After 12 weeks, histological and radiological assessment was performed. Variable callus formation was observed. No bone formation or remodeling of the graft through TRAP positive osteoclasts could be detected. Instead, a variable amount of necrotic tissue formed. Although necrotic area correlated significantly with amount of vessels and the 2-step strategy had significantly more vessels than the 1-step strategy, no significant reduction of necrotic area was found. In conclusion, the animal model developed here represents a highly challenging situation, for which a suitable engineered bone graft with better prevascularization, better resorbability and higher osteogenicity has yet to be developed.

No MeSH data available.


Related in: MedlinePlus