Deana Shenaq

Mesenchymal stem cells: Molecular characteristics and clinical applications.

Mesenchymal stem cells (MSCs) are non-hematopoietic stem cells with the capacity to differentiate into tissues of both mesenchymal and non-mesenchymal origin. MSCs can differentiate into osteoblastic, chondrogenic, and adipogenic lineages, although recent studies have demonstrated that MSCs are also able to differentiate into other lineages, including neuronal and cardiomyogenic lineages. Since their original isolation from the bone marrow, MSCs have been successfully harvested from many other tissues. Their ease of isolation and ex vivo expansion combined with their immunoprivileged nature has made these cells popular candidates for stem cell therapies. These cells have the potential to alter disease pathophysiology through many modalities including cytokine secretion, capacity to differentiate along various lineages, immune modulation and direct cell-cell interaction with diseased tissue. Here we first review basic features of MSC biology including MSC characteristics in culture, homing mechanisms, differentiation capabilities and immune modulation. We then highlight some in vivo and clinical evidence supporting the therapeutic roles of MSCs and their uses in orthopedic, autoimmune, and ischemic disorders.

Lysophosphatidic Acid Acyltransferase β (LPAATβ) Promotes the Tumor Growth of Human Osteosarcoma

Background Osteosarcoma is the most common primary malignancy of bone with poorly characterized molecular pathways important in its pathogenesis. Increasing evidence indicates that elevated lipid biosynthesis is a characteristic feature of cancer. We sought to investigate the role of lysophosphatidic acid acyltransferase β (LPAATβ, aka, AGPAT2) in regulating the proliferation and growth of human osteosarcoma cells. LPAATβ can generate phosphatidic acid, which plays a key role in lipid biosynthesis as well as in cell proliferation and survival. Although elevated expression of LPAATβ has been reported in several types of human tumors, the role of LPAATβ in osteosarcoma progression has yet to be elucidated. Methodology/Principal Findings Endogenous expression of LPAATβ in osteosarcoma cell lines is analyzed by using semi-quantitative PCR and immunohistochemical staining. Adenovirus-mediated overexpression of LPAATβ and silencing LPAATβ expression is employed to determine the effect of LPAATβ on osteosarcoma cell proliferation and migration in vitro and osteosarcoma tumor growth in vivo. We have found that expression of LPAATβ is readily detected in 8 of the 10 analyzed human osteosarcoma lines. Exogenous expression of LPAATβ promotes osteosarcoma cell proliferation and migration, while silencing LPAATβ expression inhibits these cellular characteristics. We further demonstrate that exogenous expression of LPAATβ effectively promotes tumor growth, while knockdown of LPAATβ expression inhibits tumor growth in an orthotopic xenograft model of human osteosarcoma. Conclusions/Significance Our results strongly suggest that LPAATβ expression may be associated with the aggressive phenotypes of human osteosarcoma and that LPAATβ may play an important role in regulating osteosarcoma cell proliferation and tumor growth. Thus, targeting LPAATβ may be exploited as a novel therapeutic strategy for the clinical management of osteosarcoma. This is especially attractive given the availability of selective pharmacological inhibitors.

Mesenchymal Progenitor Cells and Their Orthopedic Applications: Forging a Path towards Clinical Trials

Mesenchymal progenitor cells (MPCs) are nonhematopoietic multipotent cells capable of differentiating into mesenchymal and nonmesenchymal lineages. While they can be isolated from various tissues, MPCs isolated from the bone marrow are best characterized. These cells represent a subset of bone marrow stromal cells (BMSCs) which, in addition to their differentiation potential, are critical in supporting proliferation and differentiation of hematopoietic cells. They are of clinical interest because they can be easily isolated from bone marrow aspirates and expanded in vitro with minimal donor site morbidity. The BMSCs are also capable of altering disease pathophysiology by secreting modulating factors in a paracrine manner. Thus, engineering such cells to maximize therapeutic potential has been the focus of cell/gene therapy to date. Here, we discuss the path towards the development of clinical trials utilizing BMSCs for orthopaedic applications. Specifically, we will review the use of BMSCs in repairing critical-sized defects, fracture nonunions, cartilage and tendon injuries, as well as in metabolic bone diseases and osteonecrosis. A review of www.ClinicalTrials.gov of the United States National Institute of Health was performed, and ongoing clinical trials will be discussed in addition to the sentinel preclinical studies that paved the way for human investigations.

Video Capture of Plastic Surgery Procedures Using the GoPro HERO 3

Background: Significant improvements can be made in recoding surgical procedures, particularly in capturing high-quality video recordings from the surgeons’ point of view. This study examined the utility of the GoPro HERO 3+ Black Edition camera for high-definition, point-of-view recordings of plastic and reconstructive surgery. Methods: The GoPro HERO 3+ Black Edition camera was head-mounted on the surgeon and oriented to the surgeon’s perspective using the GoPro App. The camera was used to record 4 cases: 2 fat graft procedures and 2 breast reconstructions. During cases 1-3, an assistant remotely controlled the GoPro via the GoPro App. For case 4 the GoPro was linked to a WiFi remote, and controlled by the surgeon. Results: Camera settings for case 1 were as follows: 1080p video resolution; 48 fps; Protune mode on; wide field of view; 16:9 aspect ratio. The lighting contrast due to the overhead lights resulted in limited washout of the video image. Camera settings were adjusted for cases 2-4 to a narrow field of view, which enabled the camera’s automatic white balance to better compensate for bright lights focused on the surgical field. Cases 2-4 captured video sufficient for teaching or presentation purposes. Conclusions: The GoPro HERO 3+ Black Edition camera enables high-quality, cost-effective video recording of plastic and reconstructive surgery procedures. When set to a narrow field of view and automatic white balance, the camera is able to sufficiently compensate for the contrasting light environment of the operating room and capture high-resolution, detailed video.

Differentiation of osteoprogenitor cells is induced by high-frequency pulsed electromagnetic fields

Craniofacial defect repair is often limited by a finite supply of available autologous tissue (ie, bone) and less than ideal alternatives. Therefore, other methods to produce bony healing must be explored. Several studies have demonstrated that low-frequency pulsed electromagnetic field (PEMF) stimulation (ie, 5–30 Hz) of osteoblasts enhances bone formation. The current study was designed to investigate whether a Food and Drug Administration–approved, high-frequency PEMF–emitting device is capable of inducing osteogenic differentiation of osteoprogenitor cells. Osteoprogenitor cells (commercially available C3H10T1/2 and mouse calvarial) in complete Dulbecco modified Eagle medium were continuously exposed to PEMF stimulation delivered by the ActiPatch at a frequency of 27.1 MHz. Markers of cellular proliferation and early, intermediate, and terminal osteogenic differentiation were measured and compared with unstimulated controls. All experiments were performed in triplicate. High-frequency PEMF stimulation increases alkaline phosphatase activity in both cell lines. In addition, high-frequency PEMF stimulation augments osteopontin and osteocalcin expression as well as mineral nodule formation in C3H10T1/2 cells, indicating late and terminal osteogenic differentiation, respectively. Cellular proliferation, however, was unaffected by high-frequency PEMF stimulation. Mechanistically, high-frequency PEMF-stimulated osteogenic differentiation is associated with elevated mRNA expression levels of osteogenic bone morphogenetic proteins in C3H10T1/2 cells. Our findings suggest that high-frequency PEMF stimulation of osteoprogenitor cells may be explored as an effective tissue engineering strategy to treat critical-size osseous defects of the craniofacial and axial skeleton. AbbreviationsALP, alkaline phosphatase; BMP, bone morphogenetic protein; ERK-1, extracellular signal–regulated kinase 1; iCALs, immortalized calvarial cells; IHC, immunohistochemical; MAP, mitogen-activated protein; MSC, mesenchymal stem cell; OCN, osteocalcin; OPN, osteopontin; p38&agr;, p38-reactivating kinase; PBS, phosphate-buffered saline; PEMF, pulsed electromagnetic field

Postoperative Pain and Length of Stay Lowered by Use of Exparel in Immediate, Implant-Based Breast Reconstruction.

Background: Patients undergoing mastectomy and prosthetic breast reconstruction have significant acute postsurgical pain, routinely mandating inpatient hospitalization. Liposomal bupivacaine (LB) (Exparel; Pacira Pharmaceuticals, Inc., Parsippany, N.J.) has been shown to be a safe and effective pain reliever in the immediate postoperative period and may be advantageous for use in mastectomy and breast reconstruction patients. Methods: Retrospective review of 90 immediate implant-based breast reconstruction patient charts was completed. Patients were separated into 3 groups of 30 consecutively treated patients who received 1 of 3 pain treatment modalities: intravenous/oral narcotic pain control (control), bupivacaine pain pump, or LB injection. Length of hospital stay, patient-reported Visual Analog Scale (VAS) pain scores, postoperative patient-controlled analgesia usage, and nausea-related medication use were abstracted and subjected to analysis of variance and multiple linear-regression analysis, as appropriate. Results: Subjects were well-matched for age (P = 0.24) regardless of pain-control modality. Roughly half (53%) of control and pain pump–treated subjects had bilateral procedures, as opposed to 80% of LB subjects. Mean length of stay for LB subjects was significantly less than control (1.5 days vs 2.00 days; P = 0.016). LB subjects reported significantly lower VAS pain scores at 4, 8, 12, 16, and 24 hours compared with pain pump and control (P < 0.01). There were no adverse events in the LB group. Conclusion: Use of LB in this group of immediate breast reconstruction patients was associated with decreased patient VAS pain scores in the immediate postoperative period compared with bupivacaine pain pump and intravenous/oral narcotic pain management and reduced inpatient length of stay.

Optimizing delivery of breast conservation therapy: a multidisciplinary approach to oncoplastic surgery.

BackgroundFor patients with small breasts relative to tumor size and for those with tumors in the central or inferior poles, lumpectomy can be aesthetically devastating. The field of oncoplastic surgery has developed to offset the aesthetic pitfalls of breast conservation. Questions remain regarding oncologic safety, potential complications, and patient selection. In this study, we report our institutional, multidisciplinary experience with oncoplastic surgery. MethodsA retrospective review was performed including all patients at our institution undergoing oncoplastic breast surgery between 2003 and September 2009 at an academic medical center. Mean follow-up period was 38 months. All patients were referred by the institutional multidisciplinary breast team. ResultsForty-five female patients underwent 46 oncoplastic breast reconstructions. Immediate reconstruction was performed in 21 patients, early (within 9 to 73 days of final tumor resection) in 18, and delayed (following completion of radiation) in 6. Three patients (14%) who underwent immediate oncoplastic reconstruction had positive margins on final pathology and proceeded to completion mastectomy. No local cancer recurrence was seen. Two patients developed distant metastatic disease. Twelve complications occurred in 11 patients; by group, 2 (10%) in immediate, 7 (39%) in delayed-immediate group, and 2 (33%) in delayed. Immediate oncoplastic reconstruction, performed as a single-stage procedure, inversely correlated with complication risk (P = 0.059). No other risk factor correlated with complications. ConclusionsOur review suggests this multidisciplinary approach to oncoplastic surgery is safe. Interestingly, women undergoing immediate oncoplastic reconstruction trended toward a lower rate of complications. The benefit of immediate reconstruction must be balanced by risk of positive tumor margin and subsequent necessity for completion mastectomy. This risk–benefit balance may be best delivered by a multidisciplinary team focused on all aspects of breast cancer care.

RUNX2 quadruplication: additional evidence toward a new form of syndromic craniosynostosis.

Abstract The RUNX2 transcription factor regulates osteoblast differentiation. Its absence, as with cleidocranial dysplasia, results in deficient bone formation. However, its excess seems to follow a dose response of over ossification. RUNX2 duplications (3 copies) are exceedingly rare but have been reported to cause craniosynostosis. There are no existing reports of quadruplications (4 copies). We present a case study of a boy with an atypical skull deformity with pan-craniosynostosis whose microarray analysis revealed 4 copies of a 1.24-Mb region from 6p12.3 to 6p21.1 containing the RUNX2 gene. Further characterization of this osteogenic pathway may aid in our understanding of the pathogenesis and subsequent prevention and treatment of syndromic craniosynostosis.

Role of RANK-RANKL-OPG axis in cranial suture homeostasis.

Craniosynostosis is a significant disorder affecting 1 in 2500 live births worldwide. Although a large body of work has focused on dural regulation and the contributions of molecular mediators such as fibroblast growth factor, bone morphogenetic protein, and transforming growth factor &bgr;, minimal attention has been directed toward osteoclast function in cranial suture biology. Receptor activator of nuclear factor &kgr;B (RANK) is an essential mediator of osteoclastogenesis and osteoclast activation. In this study, physiologic fusion of posterior frontal sutures in murine development correlated with decreasing protein expression of RANK in comparison to age-matched coronal and sagittal sutures via immunohistochemical survey. However, RANK mRNA did not exhibit a similar pattern suggesting that RANK is regulated at the protein level. Fused cranial sutures in nonsyndromic craniosynostotic children also showed decreased levels of RANK staining in immunohistochemistry in comparison to patent sutures from the same patients. Immunohistochemistry with a RANK ligand antibody did not show differences in fused or patent sutures. Moreover, RANK knockdown in calvarial strip suture cultures displayed increased bone density specifically in the suture line after infection with small interfering RANK viruses. Cranial suture biology, similar to bone biology in general, likely depends on a complex interplay between osteoblasts and osteoclasts. We now report a temporospatial correlation between RANK expression and suture morphology that suggests that osteoclast activity is important in maintenance of cranial suture patency in normal physiology and disease. Furthermore, RANK downregulation promoted suture fusion establishing a causal relationship between the presence of RANK and patency.

Characterization of reversibly immortalized calvarial mesenchymal progenitor cells

Background:Bone morphogenetic proteins (BMPs) play a sentinel role in osteoblastic differentiation, and their implementation into clinical practice can revolutionize cranial reconstruction. Preliminary data suggest a therapeutic role of adenoviral gene delivery of BMPs in murine calvarial defect healing. Poor transgene expression inherent in direct adenoviral therapy prompted investigation of cell-based strategies. Objective:To isolate and immortalize calvarial cells as a potential progenitor source for osseous tissue engineering. Materials and Methods:Cells were isolated from murine skulls, cultured, and transduced with a retroviral vector bearing the loxP-flanked SV40 large T antigen. Immortalized calvarial cells (iCALs) were evaluated via light microscopy, immunohistochemistry, and flow cytometry to determine whether the immortalization process altered cell morphology or progenitor cell profile. Immortalized calvarial cells were then infected with adenoviral vectors encoding BMP-2 or GFP and assessed for early and late stages of osteogenic differentiation. Results:Immortalization of calvarial cells did not alter cell morphology as demonstrated by phase contrast microscopy. Mesenchymal progenitor cell markers CD166, CD73, CD44, and CD105 were detected at varying levels in both primary cells and iCALs. Significant elevations in alkaline phosphatase activity, osteocalcin mRNA transcription, and matrix mineralization were detected in BMP-2 treated iCALs compared with GFP-treated cells. Gross and histological analyses revealed ectopic bone production from treated cells compared with controls in an in vivo stem cell implantation assay. Conclusion:We have established an immortalized osteoprogenitor cell line from juvenile calvarial cells that retain a progenitor cell phenotype and can successfully undergo osteogenic differentiation upon BMP-2 stimulation. These cells provide a valuable platform to investigate the molecular mechanisms underlying intramembranous bone formation and to screen for factors/small molecules that can facilitate the healing of osseous defects in the craniofacial skeleton.