Autologous Homologous Skin Constructs Allow Safe Closure of Wounds: A Retrospective, Noncontrolled, Multicentered Case Series.

An autologous homologous skin construct (AHSC) has been developed for the repair and replacement of skin. It is created from a small, full-thickness harvest of healthy skin, which contains endogenous regenerative populations involved in native skin repair. A multicenter retrospective review of 15 wounds in 15 patients treated with AHSC was performed to evaluate the hypothesis that a single application could result in wound closure in a variety of wound types and that the resulting tissue would resemble native skin. Patients and wounds were selected and managed per provider's discretion with no predefined inclusion, exclusion, or follow-up criteria. Dressings were changed weekly. Graft take and wound closure were documented during follow-up visits and imaged with a digital camera. Wound etiologies included 5 acute and chronic burn, 4 acute traumatic, and 6 chronic wounds. All wounds were closed with a single application of AHSC manufactured from a single tissue harvest. Median wound, harvest, and defect-to-harvest size ratio were 120 cm2 (range, 27-4800 cm2), 14 cm2 (range, 3-20 cm2), and 11:1 (range, 2:1-343:1), respectively. No adverse reactions with the full-thickness harvest site or the AHSC treatment site were reported. Average follow-up was 4 ± 3 months. An AHSC-treated area was biopsied, and a micrograph of the area was developed using immunofluorescent confocal microscopy, which demonstrated mature, full-thickness skin with nascent hair follicles and glands. This early clinical experience with ASHC suggests that it can close different wound types; however, additional studies are needed to verify this statement.

Influence of Large-Volume Liposuction on Metabolic and Cardiovascular Health: A Systematic Review.

BACKGROUND: Evidence suggesting that adipose tissue is a metabolically active tissue has generated debate on the effects of large-volume liposuction (LVL) on metabolic and cardiovascular health. Given the inconsistency in the literature, the authors performed a systematic review to identify available evidence in order to elucidate the potential impact of LVL on metabolic markers and cardiovascular risk factors. METHODS: A PubMed search using relevant keywords was conducted. Articles were screened using predetermined inclusion and exclusion criteria. Large-volume liposuction was defined as greater than 3.5 L of lipoaspirate. All studies included evaluation of patients' preoperative and postoperative cardiovascular risk factors, inflammatory cytokines, and/or insulin resistance/sensitivity. Relevant studies were evaluated and assigned a level of evidence. RESULTS: A total of 12 studies that met the inclusion criteria were reviewed, of which 1 was a continuation of a previous study. All reports were prospective studies, 2 were randomized control trials, and 3 included a control group. A total of 364 patients were pooled for analysis. The mean volume of lipoaspirate was 7440 ± 1934.9 mL. The mean body mass index at baseline and postliposuction was 30.7 and 28.4, respectively. Seven studies reported a trend toward decrease in total cholesterol levels with an overall mean reduction of 0.21 ± 0.05 mmol/L from 4.6 ± 0.79 mmol/L to 4.4 ± 0.74 mmol/L. After LVL, leptin was reported to significantly decrease in 4 studies, and TNF-α was reported to significantly decrease in 2. Adiponectin was reported to significantly increase in 2 studies. IL-6 decreased significantly in 2 studies. Two studies included participants with type II diabetes mellitus, whereas 10 studies evaluated insulin sensitivity. Of these, 6 studies reported improvement in insulin sensitivity. Six studies represented level IV and 6 represented level II evidence. CONCLUSIONS: Liposuction is among the most common aesthetic procedures performed with advances that make it possible to remove considerable amount of adipose tissue within a short period. Current data, although conflicting, appear to support the notion that LVL can affect cardiovascular risk factors, metabolic balance, and insulin resistance in positive ways. Future research with prospective studies is needed to clarify the role of LVL in improving overall health.

Design and validation of a dynamic cell-culture system for bone biology research and exogenous tissue-engineering applications.

Bone lacunocanalicular fluid flow ensures chemotransportation and provides a mechanical stimulus to cells. Traditional static cell-culture methods are ill-suited to study the intricacies of bone biology because they ignore the three-dimensionality of meaningful cellular networks and the lacunocanalicular system; furthermore, reliance on diffusion alone for nutrient supply and waste product removal effectively limits scaffolds to 2-3 mm thickness. In this project, a flow-perfusion system was custom-designed to overcome these limitations: eight adaptable chambers housed cylindrical cell-seeded scaffolds measuring 12 or 24 mm in diameter and 1-10 mm in thickness. The porous scaffolds were manufactured using a three-dimensional (3D) periodic microprinting process and were composed of hydroxyapatite/tricalcium phosphate with variable thicknesses, strut sizes, pore sizes and structural configurations. A multi-channel peristaltic pump drew medium from parallel reservoirs and perfused it through each scaffold at a programmable rate. Hermetically sealed valves permitted sampling or replacement of medium. A gas-permeable membrane allowed for gas exchange. Tubing was selected to withstand continuous perfusion for > 2 months without leakage. Computational modelling was performed to assess the adequacy of oxygen supply and the range of fluid shear stress in the bioreactor-scaffold system, using 12 × 6 mm scaffolds, and these models suggested scaffold design modifications that improved oxygen delivery while enhancing physiological shear stress. This system may prove useful in studying complex 3D bone biology and in developing strategies for engineering thick 3D bone constructs. Copyright © 2013 John Wiley & Sons, Ltd.

Midline Cleft Lip and Bifid Nose Deformity: Description, Classification, and Treatment.

BACKGROUND: Midline facial clefts are rare and challenging deformities caused by failure of fusion of the medial nasal prominences. These anomalies vary in severity, and may include microform lines or midline lip notching, incomplete or complete labial clefting, nasal bifidity, or severe craniofacial bony and soft tissue anomalies with orbital hypertelorism and frontoethmoidal encephaloceles. In this study, the authors present 4 cases, classify the spectrum of midline cleft anomalies, and review our technical approaches to the surgical correction of midline cleft lip and bifid nasal deformities. Embryology and associated anomalies are discussed. METHODS: The authors retrospectively reviewed our experience with 4 cases of midline cleft lip with and without nasal deformities of varied complexity. In addition, a comprehensive literature search was performed, identifying studies published relating to midline cleft lip and/or bifid nose deformities. Our assessment of the anomalies in our series, in conjunction with published reports, was used to establish a 5-tiered classification system. Technical approaches and clinical reports are described. RESULTS: Functional and aesthetic anatomic correction was successfully achieved in each case without complication. A classification and treatment strategy for the treatment of midline cleft lip and bifid nose deformity is presented. CONCLUSIONS: The successful treatment of midline cleft lip and bifid nose deformities first requires the identification and classification of the wide variety of anomalies. With exposure of abnormal nasolabial anatomy, the excision of redundant skin and soft tissue, anatomic approximation of cartilaginous elements, orbicularis oris muscle repair, and craniofacial osteotomy and reduction as indicated, a single-stage correction of midline cleft lip and bifid nasal deformity can be safely and effectively achieved.

Characterization of adipose-derived mesenchymal stem cell combinations for vascularized bone engineering.

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.

Progenitor cell mobilization enhances bone healing by means of improved neovascularization and osteogenesis.

BACKGROUND: Although bone repair is a relatively efficient process, a significant portion of patients fail to heal their fractures. Because adequate blood supply is essential to osteogenesis, the authors hypothesize that augmenting neovascularization by increasing the number of circulating progenitor cells will improve bony healing. METHODS: Bilateral full-thickness defects were created in the parietal bones of C57 wild-type mice. Intraperitoneal AMD3100 (n = 33) or sterile saline (n = 33) was administered daily beginning on postoperative day 3 and continuing through day 18. Circulating progenitor cell number was quantified by fluorescence-activated cell sorting. Bone regeneration was assessed with micro-computed tomography. Immunofluorescent CD31 and osteocalcin staining was performed to assess for vascularity and osteoblast density. RESULTS: AMD3100 treatment increased circulating progenitor cell levels and significantly improved bone regeneration. Calvarial defects of AMD3100-treated mice demonstrated increased vascularity and osteoblast density. CONCLUSIONS: Improved bone regeneration in this model was associated with elevated circulating progenitor cell number and subsequently improved neovascularization and osteogenesis. These findings highlight the importance of circulating progenitor cells in bone healing and may provide a novel therapy for bone regeneration.

A novel cleft rhinoplasty procedure combining an open rhinoplasty with the Dibbell and Tajima techniques: a 10-year review.

BACKGROUND: The authors assessed the safety and efficacy of a novel cleft rhinoplasty procedure that combines an open rhinoplasty with the Dibbell and Tajima techniques. METHODS: A single-surgeon, 10-year, retrospective review was conducted of all unilateral cleft lip rhinoplasties (n = 157). Nonsyndromic patients undergoing a combined open incision/Dibbell/Tajima procedure and who had follow-up of greater than 8 months were included. Thirty-five patients were identified. Standardized patient photographs were studied in 18 patients who had both preoperative and 1-year postoperative photographs. Farkas normal values were applied to the medial canthal distance; from this value, metric measurements of changes in alar base width, columellar height, and nostril apex height were derived. RESULTS: There were no complications secondary to skin envelope ischemia or cartilage graft infection. The revision rate was 11 percent for alar base position, 3 percent for depressed lower lateral cartilage, and 3 percent for nostril apex overhang. After the procedure, there was a statistically significant decrease in alar base width (19.9 mm versus 18.2 mm; p < 0.01) and an increase in columellar height (8.37 mm versus 9.59 mm; p = 0.02) and nostril apex height (4.70 mm versus 5.44 mm; p = 0.02) on the affected side. The differences in alar base width, columellar height, and nostril apex height between the affected and nonaffected sides all decreased significantly postoperatively. CONCLUSIONS: The combined open rhinoplasty/Dibbell/Tajima procedure is safe, has a low revision rate, and is associated with a statistically significant decrease in alar base width, an increase in columellar height and nostril apex height, and a greater symmetry of nasal form.

A novel flow-perfusion bioreactor supports 3D dynamic cell culture.

BACKGROUND: Bone engineering requires thicker three-dimensional constructs than the maximum thickness supported by standard cell-culture techniques (2 mm). A flow-perfusion bioreactor was developed to provide chemotransportation to thick (6 mm) scaffolds. METHODS: Polyurethane scaffolds, seeded with murine preosteoblasts, were loaded into a novel bioreactor. Control scaffolds remained in static culture. Samples were harvested at days 2, 4, 6, and 8 and analyzed for cellular distribution, viability, metabolic activity, and density at the periphery and core. RESULTS: By day 8, static scaffolds had a periphery cell density of 67% +/- 5.0%, while in the core it was 0.3% +/- 0.3%. Flow-perfused scaffolds demonstrated peripheral cell density of 94% +/- 8.3% and core density of 76% +/- 3.1% at day 8. CONCLUSIONS: Flow perfusion provides chemotransportation to thick scaffolds. This system may permit high throughput study of 3D tissues in vitro and enable prefabrication of biological constructs large enough to solve clinical problems.

The proximally based peroneal vascular bundle: an insulated extension cord for free flap reconstruction.

Large, traumatic wounds around the proximal third of the lower extremity may have disrupted local vasculature, potentially obviating local pedicled options. However, free-tissue transfer to this area is technically challenging given the resulting paucity of recipient options and the depth of principal blood vessels. We present an anatomic and radiographic study of the proximally based peroneal vascular bundle as a recipient option in the proximal leg. Optimal approach was prone, through an incision over the fibula with dissection between lateral and posterior compartments. Magnetic resonance angiography demonstrated consistent vascular anatomy between patients. A proximally based peroneal vascular bundle protected by a cuff of flexor hallucis longus was used as a recipient vessel in free flap reconstruction of an open knee wound. The bundle itself does not require coverage by virtue of its own local muscle cuff. Caveats for its use include the need for adequate leg inflow and foot outflow.

Free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps for breast reconstruction: a systematic review of flap complication rates and donor-site morbidity.

Free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps represent increasingly popular options for breast reconstruction. Although several retrospective, small-scale studies comparing these flaps have been published, most have failed to find a significant difference in flap complication rates or donor-site morbidity. We systematically reviewed the current literature, and subsequently pooled and analyzed data from included studies. Included studies reported flap complications and/or donor site morbidities for both flap types. Eight studies met the inclusionary criteria. For flap complications, there was a statistically significant difference between deep inferior epigastric perforator and free transverse rectus abdominis myocutaneous flaps in fat necrosis rates (25.5 +/- 0.49 vs. 11.3% +/- 0.41%, P < 0.001) and total necrosis rates (4.15 +/- 0.08 vs. 1.59% +/- 0.08%, P = 0.044). Partial necrosis rates were not statistically significant (3.54 +/- 0.07 vs. 1.60% +/- 0.07%, P = 0.057). For donor-site morbidity, there was no statistically significant difference in abdominal bulge (8.07 +/- 0.23 vs. 11.25% +/- 0.29%, P = 0.28). Multicenter, prospective studies are needed to further investigate differences between these flap options.

Topical lineage-negative progenitor-cell therapy for diabetic wounds.

BACKGROUND: Impaired diabetic wound healing is due, in part, to defects in mesenchymal progenitor cell tracking. Theoretically, these defects may be overcome by administering purified progenitor cells directly to the diabetic wound. The authors hypothesize that these progenitor cells will differentiate into endothelial cells, increase wound vascularity, and improve wound healing. METHODS: Lineage-negative progenitor cells were isolated from wild-type murine bone marrow by magnetic cell sorting, suspended in a collagen matrix, and applied topically to full-thickness excisional dorsal cutaneous wounds in diabetic mice. Application of lineage-positive hematopoietic cells or acellular collagen matrix served as comparative controls (n = 16 for each group; n = 48 total). Time to closure and percentage closure were calculated by morphometry. Wounds were harvested at 7, 14, 21, and 28 days and then processed, sectioned, stained (lectin/DiI and CD31), and vascularity was quantified. RESULTS: : Wounds treated with lineage-negative cells demonstrated a significantly decreased time to closure (14 days) compared with lineage-positive (21 days, p = 0.013) and collagen controls (28 days, p = 0.004), and a significant improvement in percentage closure at 14 days compared with the lineage-positive group (p < 0.01) and the collagen control (p < 0.01). Fluorescently tagged lineage-negative cells remained viable in the wound for 28 days, whereas lineage-positive cells were not present after 7 days. Lineage-negative, but not lineage-positive, cells differentiated into endothelial cells. Vascular density and vessel cross-sectional area were significantly higher in lineage-negative wounds. CONCLUSION: Topical progenitor-cell therapy successfully accelerates diabetic wound closure and improves wound vascularity.

Biological basis of bone formation, remodeling, and repair-part III: biomechanical forces.

While it has been long appreciated that biomechanical forces are involved in bone remodeling and repair, the actual mechanism by which a physical force is translated to the corresponding intracellular signal has largely remained a mystery. To date, most biomechanical research has concentrated upon the effect on bone morphology and architecture, and it is only recently that the complex cellular and molecular pathways involved in this process (called mechanotransduction) are being described. In this paper, we review the current understanding of bone mechanobiology and highlight the implications for clinical medicine and tissue engineering research.

Nodular fasciitis of the hand over the metacarpophalangeal joint: a case report.

OBJECTIVE: This study describes a case of nodular fasciitis involving the hand and reviews the neoplasm's pertinent clinical, histologic, and pathologic features. METHODS: The patient's chart, operative record, histologic specimens, and relevant literature were reviewed. RESULTS: We report a case of nodular fasciitis involving the hand of a 55-year-old woman that was treated with marginal excision. CONCLUSIONS: Nodular fasciitis is a self-limited, benign soft tissue tumor composed of fibroblasts and myofibroblasts that typically afflicts younger patients and rarely presents in the hand. Because of its presentation, it can be easily mistaken for a malignant neoplasm. However, most cases represent a reactive and therefore a polyclonal process. Marginal excision generally provides definitive treatment.

Biological basis of bone formation, remodeling, and repair-part I: biochemical signaling molecules.

The bony biochemical environment is an active and dynamic system that permits and promotes cellular functions that lead to matrix production and ossification. Each component is capable of conveying important regulatory cues to nearby cells, thus effecting gene expression and changes at the cytostructural level. Here, we review the various signaling molecules that contribute to the active and dynamic nature of the biochemical system. These components include hormones, cytokines, and growth factors. We describe their role in regulating bone metabolism. Certain growth factors (i.e., TGF-beta, IGF-1, and VEGF) are described in greater detail because of their potential importance in developing successful tissue-engineering strategies.

Biological basis of bone formation, remodeling, and repair-part II: extracellular matrix.

The bony biochemical environment is a complex system that permits and promotes cellular functions that lead to matrix production and ossification. In Part I of this review, we discussed the important actions of signaling molecules, including hormones, cytokines, and growth factors. Here, we review other constituents of the extracellular matrix, including minerals, fibrinous and nonfibrinous proteins, and enzymes such as the matrix metalloproteinases. We conclude with a discussion of the role of biochemical modulation in endogenous and exogenous tissue engineering.