Rabie M. Shanti

Intervertebral Disc Tissue Engineering Using a Novel Hyaluronic Acid–Nanofibrous Scaffold (HANFS) Amalgam

Degeneration of the intervertebral disc (IVD) represents a significant musculoskeletal disease burden. Although spinal fusion has some efficacy in pain management, spine biomechanics is ultimately compromised. In addition, there is inherent limitation of hardware-based IVD replacement prostheses, which underscores the importance of biological approaches to disc repair. In this study, we have seeded multipotent, adult human mesenchymal stem cells (MSCs) into a novel biomaterial amalgam to develop a biphasic construct that consisted of electrospun, biodegradable nanofibrous scaffold (NFS) enveloping a hyaluronic acid (HA) hydrogel center. The seeded MSCs were induced to undergo chondrogenesis in vitro in the presence of transforming growth factor-beta for up to 28 days. The cartilaginous hyaluronic acid-nanofibrous scaffold (HANFS) construct architecturally resembled a native IVD, with an outer annulus fibrosus-like region and inner nucleus pulposus-like region. Histological and biochemical analyses, immunohistochemistry, and gene expression profiling revealed the time-dependent development of chondrocytic phenotype of the seeded cells. The cells also maintain the microarchitecture of a native IVD. Taken together, these findings suggest the prototypic potential of MSC-seeded HANFS constructs for the tissue engineering of biological replacements of degenerated IVD.

Human palatine tonsil: a new potential tissue source of multipotent mesenchymal progenitor cells

IntroductionMesenchymal progenitor cells (MPCs) are multipotent progenitor cells in adult tissues, for example, bone marrow (BM). Current challenges of clinical application of BM-derived MPCs include donor site morbidity and pain as well as low cell yields associated with an age-related decrease in cell number and differentiation potential, underscoring the need to identify alternative sources of MPCs. Recently, MPC sources have diversified; examples include adipose, placenta, umbilicus, trabecular bone, cartilage, and synovial tissue. In the present work, we report the presence of MPCs in human tonsillar tissue.MethodsWe performed comparative and quantitative analyses of BM-MPCs with a subpopulation of adherent cells isolated from this lymphoid tissue, termed tonsil-derived MPCs (T-MPCs). The expression of surface markers was assessed by fluorescent-activated cell sorting analysis. Differentiation potential of T-MPCs was analyzed histochemically and by reverse transcription-polymerase chain reaction for the expression of lineage-related marker genes. The immunosuppressive properties of MPCs were determined in vitro in mixed lymphocyte reactions.ResultsSurface epitope analysis revealed that T-MPCs were negative for CD14, CD31, CD34, and CD45 expression and positive for CD29, CD44, CD90, and CD105 expression, a characteristic phenotype of BM-MPCs. Similar to BM-MPCs, T-MPCs could be induced to undergo adipogenic differentiation and, to a lesser extent, osteogenic and chondrogenic differentiation. T-MPCs did not express class II major histocompatibility (MHC) antigens, and in a similar but less pronounced manner compared with BM-MPCs, T-MPCs were immunosuppressive, inhibiting the proliferation of T cells stimulated by allogeneic T cells or by non-specific mitogenic stimuli via an indoleamine 2,3-dioxygenase-dependent mechanism.ConclusionHuman palatine T-MPCs represent a new source of progenitor cells, potentially applicable for cell-based therapies.

In Vitro Adipose Tissue Engineering Using an Electrospun Nanofibrous Scaffold

Electrospun 3-dimensional nanofibrous scaffolds share morphologic similarities to collagen fibrils, and promote favorable biologic responses of seeded cells. In this study, we have fabricated a 3-dimensional nanofibrous scaffold made of poly L-lactic acid, and examined its ability to support and maintain the adipogenic differentiation of human bone marrow-derived mesenchymal stem cells in vitro. After a 21-day incubation, oil red O staining of constructs treated with adipogenic supplements revealed positive adipose-like staining, compared with lack of staining in untreated cultures. Semi-quantitative RT-PCR analysis of human bone marrow-derived mesenchymal stem cells cultured in adipogenic medium revealed highly elevated levels of adipogenesis-associated genes (1797-fold for lipoprotein lipase, and 5.6-fold for peroxisome proliferator-activated receptor γ). Immunofluorescence staining of cellular constructs in adipogenic culture media showed the presence of lipoprotein lipase vesicles, a characteristic feature of adipose tissue. These results suggest that the poly L-lactic acid-based nanofibrous scaffold is a promising candidate for adult stem cell-based engineering of adipose tissue.

Mesenchymal Stromal Cell‐Derived Interleukin‐6 Promotes Epithelial–Mesenchymal Transition and Acquisition of Epithelial Stem‐Like Cell Properties in Ameloblastoma Epithelial Cells

Epithelial–mesenchymal transition (EMT), a biological process associated with cancer stem‐like or cancer‐initiating cell formation, contributes to the invasiveness, metastasis, drug resistance, and recurrence of the malignant tumors; it remains to be determined whether similar processes contribute to the pathogenesis and progression of ameloblastoma (AM), a benign but locally invasive odontogenic neoplasm. Here, we demonstrated that EMT‐ and stem cell‐related genes were expressed in the epithelial islands of the most common histologic variant subtype, the follicular AM. Our results revealed elevated interleukin (IL)‐6 signals that were differentially expressed in the stromal compartment of the follicular AM. To explore the stromal effect on tumor pathogenesis, we isolated and characterized both mesenchymal stromal cells (AM‐MSCs) and epithelial cells (AM‐EpiCs) from follicular AM and demonstrated that, in in vitro culture, AM‐MSCs secreted a significantly higher level of IL‐6 as compared to the counterpart AM‐EpiCs. Furthermore, both in vitro and in vivo studies revealed that exogenous and AM‐MSC‐derived IL‐6 induced the expression of EMT‐ and stem cell‐related genes in AM‐EpiCs, whereas such effects were significantly abrogated either by a specific inhibitor of STAT3 or ERK1/2, or by knockdown of Slug gene expression. These findings suggest that AM‐MSC‐derived IL‐6 promotes tumor‐stem like cell formation by inducing EMT process in AM‐EpiCs through STAT3 and ERK1/2‐mediated signaling pathways, implying a role in the etiology and progression of the benign but locally invasive neoplasm. Stem Cells 2017;35:2083–2094

Clinical Factors Associated With Reoperation and Prolonged Length of Stay in Free Tissue Transfer to Oncologic Head and Neck Defects

Importance Prolonged hospitalization and reoperation after free tissue transfer may be associated with certain clinical factors. Objective To determine patient and surgical factors associated with length of stay (LOS) and reoperation following surgical procedures for malignant neoplasm of the head and neck involving microvascular free tissue transfer reconstruction. Design, Setting, and Participants This was a retrospective review of American College of Surgeons National Surgical Quality Improvement Program data from 2012 to 2014 using International Classification of Diseases, Ninth Revision (ICD-9), codes for malignant neoplasms of the head and neck. Multivariable logistic regression modeling was used to examine correlation of patient and surgical variables with reoperation and LOS. The national retrospective database included outcomes from community and academic participant hospitals (517 member institutions in 2014). A total of 1115 cases of head and neck malignant neoplasm ablation with microvascular free tissue transfer flap were reviewed retrospectively. Main Outcomes and Measures Incidence of reoperation within 30 days of index operation and hospitalization equal to or longer than 13.0 days, which is equal to being in the top quartile for duration of stay. Results Of the 1115 patients, 370 (33.2) were female, and the mean (SD) age was 66.8 (3.9) years. Predictors of prolonged length of stay included return to the operating room (odds ratio [OR], 4.8; 95% CI, 3.3-6.9), smoking (OR, 2.1; 95% CI, 1.5-3.1), clean-contaminated wound (OR, 2.2; 95% CI, 1.3-4.0), bony flap (OR, 1.8; 95% CI, 1.2-2.8), age (OR, 1.5; 95% CI, 1.2-1.7), and operative time (OR, 1.2; 95% CI, 1.1-1.3). Reoperation occurred 298 times for 225 patients (20.2%). Mean (SD) time to reoperation was 8.0 (7.7) days, with 180 (80%) occurring before discharge from the primary operation. The most common indications for reoperation were neck exploration (37 [12.4%]) or incision and drainage of neck (35 [11.7%]). Conclusions and Relevance American College of Surgeons National Surgical Quality Improvement Program data allow for large database analysis of free flap transfer to the head and neck. The data herein provide information to help guide surgeons on which patients will require longer stay in hospital and the most common reasons for return to the operating room. Wound class of index operation, subsequent wound-related complications, and long duration of the index operation were the primary drivers of increased risk for reoperation and, therefore, prolonged hospitalization. These same factors were also associated with prolonged hospitalization without reoperation. Level of Evidence NA.

Cellular Plasticity–Targeted Therapy in Head and Neck Cancers:

Head and neck cancer is one of the most frequent human malignancies worldwide, with a high rate of recurrence and metastasis. Head and neck squamous cell carcinoma (HNSCC) is cellularly and molecularly heterogeneous, with subsets of undifferentiated cancer cells exhibiting stem cell-like properties, called cancer stem cells (CSCs). Epithelial-mesenchymal transition, gene mutation, and epigenetic modification are associated with the formation of cellular plasticity of tumor cells in HNSCC, contributing to the acquisition of invasive, recurrent, and metastatic properties and therapeutic resistance. Tumor microenvironment (TME) plays a supportive role in the initiation, progression, and metastasis of head and neck cancer. Stromal fibroblasts, vasculature, immune cells, cytokines, and hypoxia constitute the main components of TME in HNSCC, which contributes not only to the acquisition of CSC properties but also to the recurrence and therapeutic resistance of the malignancies. In this review, we discuss the potential mechanisms underlying the development of cellular plasticity, especially the emergence of CSCs, in HNSCC. We also highlight recent studies implicating the complex interplays among TME components, plastic CSCs, tumorigenesis, recurrence, and therapeutic resistance of HNSCC. Finally, we summarize the treatment modalities of HNSCC and reinforce the novel concept of therapeutic targeting CSCs in HNSCC.

Surgical Management of Oral Cancer

Today, most head and neck cancer subsites, such as the larynx, hypopharynx, nasopharynx, and oropharynx, are treated with radiation therapy with or without chemotherapy as a primary treatment modality. Surgery is reserved for the salvage of recurrent tumors that occur within the head and neck in the absence of distant (ie, lung, liver) metastasis. However, unlike all other head and neck subsites, oral cancer should ideally be managed with primary surgery with the possibility of adjuvant radiation therapy with or without chemotherapy depending on the presence of certain high-risk pathologic features.

Ultrasonic Welded Resorbable Mesh (SonicWeld Rx System) in Reconstruction of Segmental Mandibular Defects: Technical Note and Report of 2 Cases

The present report describes 2 patients who underwent mandibular reconstruction after segmental mandibulectomy for benign pathology. The potential of an ultrasonic-aided biodegradable system for containment of a nonvascularized bone graft is discussed.

SIS-ECM Laden with GMSC-Derived Exosomes Promote Taste Bud Regeneration:

Oral cancer has a high annual incidence rate all over the world, and the tongue is the most frequently affected anatomic structure. The current standard care is ablative surgery of malignant neoplasm, followed by tongue reconstruction with free flap. However, such reconstructive modalities with postsurgery radiotherapy or chemotherapy can hardly support the functional recovery of the tongue—particularly, functional taste bud regeneration—in reconstructed areas, thus seriously affecting patients’ prognosis and life quality. Using a critical-sized tongue defect model in rats, we show that combinatory transplantation of small intestinal submucosa–extracellular matrix (SIS-ECM) with gingival mesenchymal stem cells (GMSCs) or their derivative exosomes promoted tongue lingual papillae recovery and taste bud regeneration as evidenced by increased expression of CK14, CK8, and markers for type I, II, and III taste bud cells (NTPdase 2, PLC-β2, and AADC, respectively). In addition, our results indicate that GMSCs or their derivative exosomes could increase BDNF expression, a growth factor that plays an important role in the proliferation and differentiation of epithelial basal progenitor cells into taste bud cells. Meanwhile, we showed an elevated expression level of Shh—which is essential for development, homeostasis, and maintenance of the taste bud organ—in wounded areas of the tongue among animals treated with GMSC/SIS-ECM or exosome/SIS-ECM as compared with SIS-ECM control. Moreover, our data show that GMSCs or their derivative exosomes promoted innervation of regenerated taste buds, as evidenced by elevated expressions of neurofilament and P2X3 at the injury areas. Together, our findings indicate that GMSC/SIS-ECM and exosome/SIS-ECM constructs can facilitate taste bud regeneration and reinnervation with promising potential application in postsurgery tongue reconstruction of patients with tongue cancer.

Evaluation and Staging of Oral Cancer

Although the American Joint Committee on Cancer developed its first cancer-specific staging system in 1959, the TNM classification, as it has become known, has undergone many revisions mainly due to the advancements in both diagnosis and management of cancer, Although the basic purpose of the cancer staging system has remained fundamentally unchanged, the ease with which the cancer can be staged has evolved with newer methods. This article reviews cancer evaluation for staging, as well as the introduction of a new staging method effective as of 2018.