Faculty Bibliography

Since bone repair and regeneration depend on vasculogenesis and osteogenesis, both of these processes are essential for successful vascularized bone engineering. Using adipose-derived stem cells (ASCs), we investigated temporal gene expression profiles, as well as bone nodule and endothelial tubule formation capacities, during osteogenic and vasculogenic ASC lineage commitment. Osteoprogenitor-enriched cell populations were found to express RUNX2, MSX2, SP7 (osterix), BGLAP (osteocalcin), SPARC (osteonectin), and SPP1 (osteopontin) in a temporally specific sequence. Irreversible commitment of ASCs to the osteogenic lineage occurred between days 6 and 9 of differentiation. Endothelioprogenitor-enriched cell populations expressed CD34, PECAM1 (CD31), ENG (CD105), FLT1 (Vascular endothelial growth factor [VEGFR1]), and KDR (VEGFR2). Capacity for microtubule formation was evident in as early as 3 days. Functional capacity was assessed in eight coculture combinations for both bone nodule and endothelial tubule formation, and the greatest expression of these end-differentiation phenotypes was observed in the combination of well-differentiated endothelial cells with less-differentiated osteoblastic cells. Taken together, our results demonstrate vascularized bone engineering utilizing ASCs is a promising enterprise, and that coculture strategies should focus on developing a more mature vascular network in combination with a less mature osteoblastic stromal cell.

Bone repair and regeneration are dynamic processes that involve a complex interplay between the substrate, local and systemic cells, and the milieu. Although each constituent plays an integral role in faithfully recreating the skeleton, investigators have long focused their efforts on scaffold materials and design, cytokine and hormone administration, and cell-based therapies. Only recently have the intangible aspects of the milieu received their due attention. In this review, we highlight the important influence of environmental factors on bone tissue engineering. (c) 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.

ABSTRACT: Preoperative nasoalveolar molding (NAM) in combination with primary gingivoperiosteoplasty (GPP) reduces the need for secondary alveolar bone grafting by 60% in patients with unilateral cleft lip and palate (CL/P). Herein, we investigate the efficacy of NAM and primary GPP in patients with bilateral CL/P. All patients (n = 38) with bilateral CL/P who underwent NAM and primary GPP from 1988 to 1998 with at least 14 years of follow-up were included in this study. Panoramic and periapical radiographs were used to assess dentoalveolar bone formation. A total of 38 patients were identified with median follow-up of 18 years (range 14-26 years). Of the 27 patients who underwent bilateral GPP, 14 (51%) patients had successful dentoalveolar bone formation bilaterally and 13 (49%) had unilateral bone formation. No patient had a bilateral failure. Of the 11 patients who underwent unilateral GPP, 7 (63%) patients had successful dentoalveolar bone formation. Bilateral successful dentoalveolar bone formation following primary bilateral GPP has a dependent probability of 52% and a conditional probability of 82%.

ABSTRACT: Despite significant advances in cleft lip and palate treatment, anatomical controversies remain. Some have proposed that the width of the cleft is due to alveolar segmental displacement. Others suggest that the width is due to palatoalveolar hypoplasia. Improving our understanding of cleft anatomy may have implications for presurgical orthopedics and tissue engineering therapies. Palatoalveolar impressions of 17 noncleft children and 11 children with complete (alveolar, primary, and secondary) unilateral cleft palates were taken. Maxillary tuberosity positions and maxillary volumes were compared. Tuberosity position was determined by facebow transfer of palatoalveolar casts into geodetic datum boxes, and identification of the Cartesian coordinates (x, y, z) of the tuberosities relative to the box surfaces and Frankfurt horizontal. Maxillary volume was determined by immersing the palatoalveolar casts and measuring sand displacement. A significant difference was noted in the average tuberosity to contralateral tuberosity distance between cleft and noncleft cohorts. On average, cleft palate tuberosities were laterally displaced 8.7 mm compared with noncleft palates (P < 0.05). There was neither statistically significant alveolar segment elevation nor retroversion. A significant difference was noted in the average palatoalveolar volumes. The cleft palatoalveolar volume was 5.7 cm, and the noncleft palatoalveolar volume was 7.2 cm (P < 0.05). A palatal cleft is due to both alveolar tissue displacement and deficiency. Therefore, ideal cleft palate care should involve the correction of a displaced and deficient alveolus.

ABSTRACT: The incidence of postoperative complications in cleft care is low. In this 19-year retrospective analysis of cleft lip and palate patients treated with preoperative nasoalveolar molding, we examine the incidence of postoperative oronasal fistulae. The charts of 178 patients who underwent preoperative nasoalveolar molding by the same orthodontist/prosthodontist team and primary cleft lip/palate repair by the same surgeon over a 19-year period were reviewed. Millard, Mohler, Cutting, or Mulliken-type techniques were used for cleft lip repairs. Oxford-, Bardach-, or von Langenbeck-type techniques were used for cleft palate repairs. One nasolabial fistula occurred after primary cleft lip repair (0.56% incidence) and was repaired surgically. Four palatal fistulae (3 at the junction between soft and hard palate and 1 at the right anterior palate near the incisive foramen) occurred, but 3 healed spontaneously. Only 1 palatal fistula (0.71%) required surgical repair. All 5 fistulae occurred within the first 8 years of the study period, with 4 (80%) of 5 occurring within the first 3 years. Although fistula rate may be related to surgeon experience and the evolution of presurgical techniques, nasoalveolar molding in conjunction with nasal floor closure contributes to a low incidence of oronasal fistulae.

ABSTRACT: Nearly 60 years ago, Joseph Murray described several advancements to Bradford Cannon's Abbe flap reconstruction of secondary bilateral cleft lips in order to simplify the technique and improve results. Unlike their predecessors, Drs. Cannon and Murray modified the Abbe flap by splitting its apex in order to obtain a symmetrical correction of the upper lip and allow the 2 suture lines to extend vertically and laterally past the base of the columella and disappear within the floor of the nose. Eighteen years later, Dr. Murray reviewed the evolution of his own secondary cleft lip reconstruction experience to include a new approach to advance the maxilla rather than set back the mandible. In this Signature Issue, we reflect on contemporary innovations in secondary bilateral cleft lip Abbe flap reconstruction. Today, we approach the secondary reconstruction of the bilateral cleft lip in 3 stages. First, we establish normal anatomic positioning of the midface. Second, we perform secondary cleft nasal surgery as necessary. Finally, only after the midfacial skeleton and nose have been treated do we proceed with Abbe flap reconstruction of the upper lip. We inset the Abbe flap a quarter of the way out on the columella and wrap the Abbe darts around the sides of the columella. We find that designing the Abbe flap this way avoids the saber cut-like notching at the lip-columella junction, redundant vermilion, and excess flap length, and it also reduces or eliminates the need for upper or lower lip scar revision.

ABSTRACT: Among the craniosynostosis syndromes, Pfeiffer syndrome is notable because of high mortality and the need for multiple surgical interventions. However, it is variable in severity. We propose a new classification of Pfeiffer Syndrome to define pathology and function. A retrospective review was conducted of 42 patients with Pfeiffer syndrome treated from 1975 to 2010, the largest series reported to date. The classification was based on a functional assessment of patients in terms of respiratory, ocular, otological, and neurological status. This classification was tested by scoring and stratifying patients as follows: type A (mild problems), B (moderate problems), or C (severe problems). Patients were scored both at the time of presentation and after all surgical interventions to assess change in functional outcome. The functional classification system was compared to another previously reported. Type A patients did not have any change in postoperative functional outcomes (mean preoperative score 1.6, mean postoperative score 1.6); type B patients showed functional improvement (mean preoperative score 4.1, mean postoperative score 3.4) but type C patients (mean preoperative score 7.7, mean postoperative score 4.8) demonstrated the greatest improvement in functional scores after surgical intervention. Suture pathology did not indicate the clinical severity of phenotype, a variance from a previously published classification. The proposed classification is useful to assess severity of phenotype: respiratory, ocular, otologic, and neurologic problems are key indicators of the need for treatment. The classification can provide a helpful guide in multidisciplinary treatment planning, in reporting outcomes, and in the sharing of data among craniofacial anomalies centers.

BACKGROUND: : The graying of our population has motivated the authors to better understand age-related impairments in wound healing. To increase research throughput, the authors hypothesized that the Hutchinson-Gilford progeria syndrome Zmpste24-deficient (Zmpste24) mouse could serve as a model of senescent wound healing. METHODS: : Using a stented excisional wound closure model, the authors tested this hypothesis on 8-week-old male Zmpste24 mice (n = 25) and age-matched male C57BL/6J wild-type mice (n = 25). Wounds were measured photogrammetrically and harvested for immunohistochemistry, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction, and circulating vasculogenic progenitor cells were measured by flow cytometry. RESULTS: : Zmpste24 mice had a significant delay in wound closure compared with wild-type mice during the proliferative/vasculogenic phase. Zmpste24 wounds had decreased proliferation, increased 8-hydroxy-2'-deoxyguanosine levels, increased proapoptotic signaling (i.e., p53, PUMA, BAX), decreased antiapoptotic signaling (i.e., Bcl-2), and increased DNA fragmentation. These changes correlated with decreased local vasculogenic growth factor expression, decreased mobilization of bone marrow-derived vasculogenic progenitor cells, and decreased new blood vessel formation. Age-related impairments in wound closure are multifactorial. CONCLUSIONS: : The authors' data suggest that the Hutchinson-Gilford progeria syndrome Zmpste24 progeroid syndrome shares mechanistic overlap with normal aging and therefore might provide a uniquely informative model with which to study age-associated impairments in wound closure.

Encased in lacunae, osteocytes receive nutrition and biomechanical signals through the lacunocanalicular system. We have developed a novel flow-perfusion bioreactor designed to support lacunocanalicular fluid flow. We hypothesize that ex vivo fluid flow can maintain endochondral bone viability and, ultimately, serve as a novel model to study bone biology in vitro. Sprague-Dawley rat femurs were harvested, stripped of soft tissue, loaded into a custom-designed bioreactor and perfused with osteogenic culture medium. After 14 days of flow-perfusion or static culture, the bones were harvested, fixed, decalcified, embedded, sectioned and stained with haematoxylin and eosin. Fresh long bone samples were similarly processed for comparison. Osteocyte viability and function were also evaluated, using thiazolyl blue tetrazolium bromide (MTT), fluorospectrophotometric DNA quantification, alkaline phosphatase (ALP) colorimetric assay and fluorochrome labelling of mineralizing surfaces. All samples remained free of infection throughout the study period. After 14 days of flow perfusion, histological analysis showed normal-appearing bony architecture, with 72% of lacunae being osteocyte-filled compared with 93% in freshly harvested samples and only 36% in static samples. MTT staining and assay confirmed osteocyte viability in the flow-perfusion samples as well as in fresh samples. DNA quantification demonstrated DNA to be preserved in flow-perfused samples when compared with freshly harvested samples. ALP activity in flow-perfusion explants was upregulated compared with fresh and static samples. Fluorochrome-labelled mineralizing surfaces were seen throughout the explanted flow-perfused samples. This is the first demonstration that flow perfusion provides adequate chemotransportation to explanted murine endochondal bones