MOLD-SHAPED, NANOFIBER SCAFFOLD-BASED CARTILAGE ENGINEERING USING HUMAN MESENCHYMAL STEM CELLS AND BIOREACTOR

Background Mesenchymal stem cell (MSC)-based tissue engineering is a promising future alternative to autologous cartilage grafting. This study evaluates the potential of using MSCs, seeded into electrospun, biodegradable polymeric nanofibrous scaffolds, to engineer cartilage with defined dimensions and shape, similar to grafts used for subcutaneous implantation in plastic and reconstructive surgery. Materials and methods Human bone marrow derived MSCs seeded onto nanofibrous scaffolds and placed in custom-designed molds were cultured for up to 42 days in bioreactors. Chondrogenesis was induced with either transforming growth factor-β1 (TGF-β1) alone or in combination with insulin-like growth factor-I (IGF-I). Results Constructs exhibited hyaline cartilage histology with desired thickness and shape as well as favorable tissue integrity and shape retention, suggesting the presence of elastic tissue. Time-dependent increase in cartilage matrix gene expression was seen in both types of culture; at Day 42, TGF-β1/IGF-I treated cultures showed higher collagen type II and aggrecan expression. Both culture conditions showed significant time-dependent increase in sulfated glycosaminoglycan and hydroxyproline contents. TGF-β1/IGF-I treated samples were significantly stiffer; with equilibrium compressive Young’s modulus values reaching 17 kPa by Day 42. Conclusions The successful ex vivo development of geometrically defined cartilaginous construct using customized molding suggests the potential of cell-based cartilage tissue for reconstructive surgery

Activin A expression regulates multipotency of mesenchymal progenitor cells

INTRODUCTION. Bone marrow (BM) stroma currently represents the most common and investigated source of mesenchymal progenitor cells (MPCs); however, comparable adult progenitor or stem cells have also been isolated from a wide variety of tissues. This study aims to assess the functional similarities of MPCs from different tissues and to identify specific factor(s) related to their multipotency. METHODS. For this purpose, we directly compared MPCs isolated from different adult tissues, including bone marrow, tonsil, muscle, and dental pulp. We first examined and compared proliferation rates, immunomodulatory properties, and multidifferentiation potential of these MPCs in vitro. Next, we specifically evaluated activin A expression profile and activin A:follistatin ratio in MPCs from the four sources. RESULTS. The multidifferentiation potential of the MPCs is correlated with activin A level and/or the activin A:follistatin ratio. Interestingly, by siRNA-mediated activin A knockdown, activin A was shown to be required for the chondrogenic and osteogenic differentiation of MPCs. These findings strongly suggest that activin A has a pivotal differentiation-related role in the early stages of chondrogenesis and osteogenesis while inhibiting adipogenesis of MPCs. CONCLUSIONS. This comparative analysis of MPCs from different tissue sources also identifies bone marrow-derived MPCs as the most potent MPCs in terms of multilineage differentiation and immunosuppression, two key requirements in cell-based regenerative medicine. In addition, this study implicates the significance of activin A as a functional marker of MPC identity.National Institute of Arthritis, and Musculoskeletal and Skin Diseases; National Institutes of Health (ZO1 AR 41131, 01 DE019156-01

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

INTRODUCTION: Mesenchymal 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. ----- METHODS: We 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. ----- RESULTS: Surface 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. ----- CONCLUSION: Human palatine T-MPCs represent a new source of progenitor cells, potentially applicable for cell-based therapies

Functional cartilage repair capacity of de-differentiated, chondrocyte- and mesenchymal stem cell-laden hydrogels in vitro

International audienceObjective: The long-term performance of cell-seeded matrix-based cartilage constructs depends on (1) the development of sufficient biomechanical properties, and (2) lateral integration with host tissues, both of which require cartilage-specific matrix deposition within the scaffold. In this study, we have examined the potential of tissue-engineered cartilage analogs developed using different cell types, i.e., mesenchymal stem cells (MSCs) vs chondrocytes and de-differentiated chondrocytes, in an established "construct in cartilage ring" model.Design: Cell-laden constructs of differentiated chondrocytes, de-differentiated chondrocytes after two, five or eight population doublings, and MSCs were either implanted into a native cartilage ring immediately after fabrication (immature group) or pre-treated for 21 days in a transforming growth factor-β3 (TGF-β3) containing medium prior to implantation. After additional culture for 28 days in a serum-free, chemically defined medium, the extent of lateral integration, and biochemical and biomechanical characteristics of the implants as hybrid constructs were assessed.Results: The quality of integration, the amount of accumulated cartilage-specific matrix components and associated biomechanical properties were found to be highest when using differentiated chondrocytes. De-differentiation of chondrocytes negatively impacted the properties of the implants, as even two population doublings of the chondrocytes in culture significantly lowered cartilage repair capacity. In contrast, MSCs showed chondrogenic differentiation with TGF-β3 pre-treatment and superior integrational behavior.Conclusions: Chondrocyte expansion and de-differentiation impaired the cell response, resulting in inferior cartilage repair in vitro. With TGF-β3 pre-treatment, MSCs were able to undergo sustained chondrogenic differentiation and exhibited superior matrix deposition and integration compared to de-differentiated chondrocytes

Volumetric facelift: Evaluation of rhytidectomy with alloplastic augmentation

Objectives: Facial aging occurs as a result of soft tissue atrophy and resorption of the bony skeleton, which results in a loss of soft tissue volume and laxity of the overlying skin. Volumetric augmentation is a key component of facial rejuvenation surgery, and should be considered of equal importance to soft tissue lifting. Augmentation can be accomplished with synthetic fillers, autologous grafts, soft tissue repositioning techniques, and/or alloplastic implants. Only alloplastic implants, however, provide truly long-term volumetric correction. To date, there have been no large series dealing with the complications and results of implantation performed concurrently with rhytidectomy, which we have termed volumetric rhytidectomy. We present our experience with 100 patients treated with a combination of malar and chin implants and rhytidectomy, compared to 200 patients who underwent rhytidectomy alone. Methods: The authors performed a retrospective review of patients treated with a combination of silicone malar and chin augmentation with rhytidectomy versus patients treated with rhytidectomy alone. Both groups of patients underwent close postoperative evaluation at 3 days, 1 week, 2 weeks, and 1 month. All patients were surveyed at 6 months to assess aesthetic satisfaction. Complication rates were noted and tabulated. Statistical analysis was performed to evaluate for any differences in the two groups. Results: Between 2002 and 2006, 100 patients underwent malar and chin implantation along with rhytidectomy; 200 patients underwent rhytidectomy alone. In the first group, there were a total of 6 cases in which implant removal was necessary, and 2 cases in which revision was required. There were no statistically significant differences (p \u3c 0.05) observed between the two groups with respect to major or minor hematoma, seroma, infection, sensory nerve injury, facial nerve injury, hypertrophic scarring, dehiscence, skin sloughing, or revision. Conclusions: Volumetric rhytidectomy reliably augments the malar and mental areas, allows for subtle skeletal contouring, and results in successful rejuvenation. Rhytidectomy is relatively safe to perform concurrently with silicone augmentation, and does not result in an increased complication rate as compared to rhytidectomy alone. © 2010 Annals Publishing Company. All rights reserved

Does suture material and technique really matter? Lessons learned from 800 consecutive blepharoplasties

OBJECTIVES: The purpose of this study was to evaluate established suture materials and techniques for blepharoplasty closure and evaluate for any differences in rates of complications between these groups. STUDY DESIGN AND METHODS: This was a prospective study of a large sequential series of patients undergoing upper blepharoplasty who were treated by the same senior author over a 5-year period. Patients were assigned one of four techniques for closure of the incision based on the senior author\u27s experience. After 6 weeks, rates of complications and revisions were noted and addressed. Satisfaction rates were noted at 3 months. RESULTS: In the group whose incisions were closed with running subcuticular polypropylene (Prolene), 5 (2.5%) presented with milia, and 11 (5.5%) had a standing cone deformity (SCD). Use of running cutaneous locked Prolene resulted in 8 patients (17%) with milia and 2 patients (4.4%) requiring revision of a SCD. Use of a running 6-0 plain gut suture resulted in 12 patients (6.7%) with milia and 5 patients (2.8%) with unsightly scarring. In the group whose incisions were closed with running 6-0 fast-absorbing gut, 10 patients (2%) presented with milia, and there were no scar revisions. There were statistically significant differences between the groups with respect to formation of milia, scarring, and persistent erythema (P \u3c .008). CONCLUSIONS: Blepharoplasty is a safe and effective procedure that can be performed successfully with several established techniques. In our experience, closure with two interrupted 6-0 Prolene sutures and a running 6-0 fast-absorbing gut resulted in the lowest rates of complications and revisions. © The American Laryngological, Rhinological & Otological Society, Inc

The S-Plus lift: a short-scar, long-flap rhytidectomy

INTRODUCTION: As rhytidectomy is one of the most elective surgical procedures, there is a strong trend toward less aggressive operative techniques. The authors introduce the S-Plus lift, a \u27long flap\u27 superficial musculo-aponeurotic system (SMAS) imbrication technique that diminishes risks, decreases recovery time, and yields long-lasting results. PATIENTS AND METHODS: This paper describes a novel approach to mid-facial rejuvenation that combines the limited incision of an S-lift with two SMASectomies, purse-string suture imbrication of the extended supraplatysmal plane (ESP) and SMAS, and malar soft tissue suspension. SMAS excisions are performed pre-auricularly, and in the region overlying the anterior edge of the parotid gland. Purse-string imbrication sutures are designed to close the SMAS defects, pull the soft tissues of the neck upward, pull the jowl and lower face posteriorly and superiorly, and tighten the platysma. Ancillary purse-string suture lifts the malar fat pad and cheek soft tissues vertically, which achieves mid-face fullness and lifting. Compared to S-lift, the technique extends its efficacy in those patients who have moderate-to-severe mid-facial laxity, prominent nasolabial folds, and platysma redundancy. RESULTS: A review of 144 consecutive S-Plus lifts performed by a single surgeon (SBH), with at least 6 months of follow-up, was performed. Over a 3-year period, 130 (90.3%) females and 14 (9.7%) males underwent S-Plus lift. S-Plus lift as primary rhytidectomy was performed in 132 (91.7%) and as secondary in 12 (8.3%) cases. Complication rate was low and comparable with other techniques of rhytidectomy. CONCLUSIONS: The S-Plus lift is a novel, hybrid technique with pleasing results, short down-time, and high patient satisfaction rate. The technique combines two SMASectomies with purse-string suture imbrication of the ESP and SMAS, and malar fat suture suspension