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Kenton D Fong

Publications and source records attributed to Kenton D Fong.

6 recordsLinked to original sources
PubMed2003

Tools and techniques for craniofacial tissue engineering.

Craniofacial surgery is an important conduit for tissue-engineering applications. As interdisciplinary collaborations improve, we can expect to see remarkable progress in de novo tissue synthesis, replacement, and repair. Ultimately, we may one day find that gene-modified cell-based tissue-engineering strategies will succeed today's reconstructive strategies. In this review, we highlight the major gene- and cell-based preclinical tools and techniques that are currently being developed to solve common craniofacial problems.

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PubMed2003

New strategies for craniofacial repair and replacement: a brief review.

Craniofacial anomalies can severely affect the appearance, function, and psychosocial well being of patients; thus, tissue engineers are developing new techniques to functionally and aesthetically rebuild craniofacial structures. In the past decade, there have been tremendous advances in the field of tissue engineering that will substantially alter how surgeons approach craniofacial reconstruction. In this brief review, we highlight some of the preclinical recombinant protein, gene transfer, and cell-based strategies currently being developed to augment endogenous tissue repair or create structures for replacement. In addition, we discuss the importance of studying endogenous models of tissue induction and present some of the current in vitro and in vivo approaches to growing complex tissues/organs for craniofacial reconstruction.

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PubMed2003

Equibiaxial tensile strain affects calvarial osteoblast biology.

Mechanical tensile strain is believed to play an important role in regulating calvarial morphogenesis. To better understand the effects of mechanical strain on pathologic calvarial growth, we applied 10% constant equibiaxial tensile strain to neonatal rat calvarial osteoblast cultures and examined cellular proliferation, cytokine production, and extracellular matrix molecule expression. Mechanical strain markedly increased osteoblast proliferation as demonstrated by increased proliferating cell nuclear antigen (PCNA) protein. In addition, both transforming growth factor-beta1 (TGF-beta1) mRNA expression and fibroblast growth factor-2 (FGF-2) protein production were increased with exposure to strain. Moreover, mechanical strain induced expression of the extracellular matrix molecule collagen IalphaI. To further explore the relationship between mechanotransduction, osteogenesis, and angiogenesis, we examined the effect of mechanical strain on calvarial osteoblast expression of vascular endothelial growth factor (VEGF). Interestingly, we found that mechanical strain induced a rapid (within 3 hrs) increase in osteoblast VEGF expression. These data suggest that constant equibiaxial tensile strain-induced mechanotransduction can influence osteoblasts to assume an "osteogenic" and "angiogenic" phenotype, and these findings may have important implications for understanding the mechanisms of pathologic strain-induced calvarial growth.

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PubMed2003

Regional dura mater differentially regulates osteoblast gene expression.

Recent studies have suggested that regionally differentiated dura mater regulates murine cranial suture fate by providing growth factors to the osteoblasts in the overlying suture complex. To determine if regionally differentiated dura mater is capable of effecting changes in osteoblast gene expression, an in vitro coculture system was established in which osteoblast-enriched cell cultures derived from neonatal rat calvaria were grown in serum-free media in the presence of dural cells derived from posterior frontal (PF) or sagittal (SAG) dural tissues, recapitulating the in situ relation between the underlying dura mater and the osteoblasts in the overlying cranial suture. In this study, the changes in osteoblast gene expression induced by signaling from regional dura mater were examined by analyzing total cellular RNA isolated from osteoblasts cocultured with PF or SAG dural cells. The expression of extracellular matrix molecules (alkaline phosphatase, bone sialoprotein, osteopontin, and osteocalcin) and the transcription factor Msx2 was assessed. Consistent with previous data, the findings demonstrate that osteoblasts cocultured with dural cells undergo changes in gene expression indicative of a more differentiated osteoblast. Additionally, the data suggest that regionally differentiated dura mater isolated from the PF suture enhances the expression of osteogenic genes to a greater extent than SAG suture-derived dural cells. These data support an osteoinductive role for suture-derived dural cells in vitro that may have implications for suture biology in vivo.

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PubMed2003

FGF-2 stimulation affects calvarial osteoblast biology: quantitative analysis of nine genes important for cranial suture biology by real-time reverse transcription polymerase chain reaction.

Appropriately timed closure of the cranial sutures is a critical factor in normal postnatal morphogenesis of the cranial vault. Suture patency is necessary to permit rapid neonatal expansion of the cerebral hemispheres, and later ossification is important for bony protection of the cerebrum. Premature suture ossification (craniosynostosis) leads to myriad adverse functional and developmental consequences. Several murine studies have implicated dura-derived fibroblast growth factor-2 (FGF-2) paracrine signaling as a critical factor promoting physiologic posterior frontal suture fusion. In this study, the authors used real-time reverse transcription polymerase chain reaction (RT-PCR) to study an in vitro system that models the in vivo stimulation of suture calvarial osteoblasts by dura-derived FGF-2. The authors advocate real-time RT-PCR as a powerful and rapid technique that offers advantages in the highly sensitive, specific, and reproducible analyses of nine genes known to be important in cranial suture biology. The genes studied were growth factors [FGF-2, transforming growth factor (TGF)-beta 1, TGF-beta 2, and TGF-beta 3], growth factor receptors (FGF-R1, FGF-R2, TGF-beta RI, and TGF-beta RII), and a marker of osteoblast differentiation (Co1-I alpha I). These analyses provide a "snapshot" of several important genes involved in suture fusion that is more inclusive and quantitative than that which has been previously reported.

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