14 research outputs found

    Engineering new bone tissue in vitro on highly porous poly(Α-hydroxyl acids)/hydroxyapatite composite scaffolds

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    Engineering new bone tissue with cells and a synthetic extracellular matrix (scaffolding) represents a new approach for the regeneration of mineralized tissues compared with the transplantation of bone (autografts or allografts). In the present work, highly porous poly( L -lactic acid) (PLLA) and PLLA/hydroxyapatite (HAP) composite scaffolds were prepared with a thermally induced phase separation technique. The scaffolds were seeded with osteoblastic cells and cultured in vitro . In the pure PLLA scaffolds, the osteoblasts attached primarily on the outer surface of the polymer. In contrast, the osteoblasts penetrated deep into the PLLA/HAP scaffolds and were uniformly distributed. The osteoblast survival percentage in the PLLA/HAP scaffolds was superior to that in the PLLA scaffolds. The osteoblasts proliferated in both types of the scaffolds, but the cell number was always higher in the PLLA/HAP composite scaffolds during 6 weeks of in vitro cultivation. Bone-specific markers (mRNAs encoding bone sialoprotein and osteocalcin) were expressed more abundantly in the PLLA/HAP composite scaffolds than in the PLLA scaffolds. The new tissue increased continuously in the PLLA/HAP composite scaffolds, whereas new tissue formed only near the surface of pure PLLA scaffolds. These results demonstrate that HAP imparts osteoconductivity and the highly porous PLLA/HAP composite scaffolds are superior to pure PLLA scaffolds for bone tissue engineering. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res 54: 284–293, 2001Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34419/1/16_ftp.pd

    Salivary exRNA biomarkers to detect gingivitis and monitor disease regression

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    AimThis study tests the hypothesis that salivary extracellular RNA (exRNA) biomarkers can be developed for gingivitis detection and monitoring disease regression.Materials and MethodsSalivary exRNA biomarker candidates were developed from a total of 100 gingivitis and nonâ gingivitis individuals using Affymetrix’s expression microarrays. The top 10 differentially expressed exRNAs were tested in a clinical cohort to determine whether the discovered salivary exRNA markers for gingivitis were associated with clinical gingivitis and disease regression. For this purpose, unstimulated saliva was collected from 30 randomly selected gingivitis subjects, the gingival and plaque indexes scores were taken at baseline, 3 and 6 weeks and salivary exRNAs were assayed by means of reverse transcription quantitative polymerase chain reaction.ResultsEight salivary exRNA biomarkers developed for gingivitis were statistically significantly changed over time, consistent with disease regression. A panel of four salivary exRNAs [SPRR1A, lncâ TET3â 2:1, FAM25A, CRCT1] can detect gingivitis with a clinical performance of 0.91 area under the curve, with 71% sensitivity and 100% specificity.ConclusionsThe clinical values of the developed salivary exRNA biomarkers are associated with gingivitis regression. They offer strong potential to be advanced for definitive validation and clinical laboratory development test.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144647/1/jcpe12930.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144647/2/jcpe12930_am.pd

    Carranza's:Clinical periodontology

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    The bone regenerative effect of platelet derived growth factor-BB delivered with a chitosan/tricalcium phospahate matrix carrier

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    Background: In order to achieve optimal effects, growth factors including platelet-derived growth factor (PDGF) should be delivered with a biodegradable carrier that will release therapeutic concentrations over a sufficient length of time. The purpose of this study was to evaluate the bone regenerative effect of PDGF-BB delivered with a chitosan/tricalcium phosphate (TCP) sponge carrier in a rat calvarial defect model. Methods: The PDGF-BB–loaded chitosan/TCP sponge carrier was fabricated by freeze-drying a mixture of chitosan solution and TCP powder and soaking in a PDGF-BB solution. The release kinetics of PDGF-BB loaded onto the sponge were measured in vitro with 125I-labeled PDGF-BB. Chitosan/TCP sponges with and without PDGF-BB were implanted into 8 mm calvarial defects in rats. Rats were sacrificed at 2 and 4 weeks following implantation, and histologic and histomorphometrical examinations were performed.c Results: In vitro evaluation demonstrated that an effective therapeutic concentration of PDGF-BB following a high initial burst release was maintained throughout the examination period. In the histologic examination, the chitosan/TCP sponge carrier promoted osseous healing of the rat calvarial defects as compared to controls. The addition of PDGF-BB to the carrier further enhanced bone regeneration. Evidence of the degraded sponge matrix was observed mingled within the newly formed bone without connective tissue encapsulation. Conclusions: The results of this study support the use of chitosan/ TCP sponges as a delivery system for growth factors and demonstrate that PDGF-BB loaded onto chitosan/TCP sponge carriers has an osteogenic effect on bone regeneration in vivo. J Periodontol 2000;71:418-424
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