RESUMO
The potential use of stem cell-based therapies for the repair and regeneration of various tissues and organs offers a paradigm shift in plastic and reconstructive surgery. The use of either embryonic stem cells (ESC) or induced pluripotent stem cells (iPSC) in clinical situations is limited because of regulations and ethical considerations even though these cells are theoretically highly beneficial. Adult mesenchymal stem cells appear to be an ideal stem cell population for practical regenerative medicine. Among these cells, adipose-derived stem cells (ADSC) have the potential to differentiate the mesenchymal, ectodermal and endodermal lineages and are easy to harvest. Additionally, adipose tissue yields a high number of ADSC per volume of tissue. Based on this background knowledge, the purpose of this review is to summarise and describe the proliferation and differentiation capacities of ADSC together with current preclinical data regarding the use of ADSC as regenerative tools in plastic and reconstructive surgery.
Assuntos
Tecido Adiposo/crescimento & desenvolvimento , Procedimentos de Cirurgia Plástica/métodos , Regeneração/fisiologia , Transplante de Células-Tronco/métodos , Células-Tronco/fisiologia , Cirurgia Plástica/métodos , Animais , HumanosRESUMO
PURPOSE: To describe a fibrocartilaginous structure on the dorsal surface of the metacarpophalangeal (MCP) joint. METHODS: A combination of anatomical dissection, histology, ultrasound, and magnetic resonance imaging was undertaken to explore the anatomical structure described, with clinical correlation undertaken by surgical exploration of MCP joints. RESULTS: A dorsal structure of the MCP joint was identified as fibrocartilagenous in composition, triangular in shape, and-together with the volar plate and collateral and accessory collateral ligaments-forming a deepened dorsal fossa in which the metacarpal head invaginated. It was attached to the extensor tendon by loose connective tissue and formed part of the joint capsule. CONCLUSIONS: The dorsal fibrocartilage of the MCP joint is a constant anatomical structure that appears to complement the structural support for the metacarpal head and extensor tendon. Possible functions include stabilization of the extensor tendon, formation of a dorsal fossa, prevention of extensor tendon attrition, and synovial fluid production. Its structure and function may have implications in future development of joint replacement devices. CLINICAL RELEVANCE: This study adds to the collective knowledge about the precise anatomy of the MCP joint. Reconstructive surgery and, in particular, joint replacement surgery should consider the potential function and importance of this structure when designing interventions on the joint.
Assuntos
Articulação Metacarpofalângica/anatomia & histologia , Fibrocartilagem Triangular/anatomia & histologia , Idoso , Idoso de 80 Anos ou mais , Cadáver , Dissecação , Humanos , Imageamento por Ressonância Magnética , Articulação Metacarpofalângica/diagnóstico por imagem , Pessoa de Meia-Idade , Fibrocartilagem Triangular/diagnóstico por imagem , UltrassonografiaRESUMO
A multidisciplinary approach to the management of tongue cancer is vital for achieving optimal patient outcomes. Nursing and allied health professionals play essential roles within the team. We developed symposia comprising a series of online lectures offering a detailed perspective on the role each discipline and consumer perspective has in the management of patients with tongue cancer. The topics, including epidemiology and prevention, diagnosis, treatment planning, surgery, adjuvant care, and the management of recurrent or metastatic disease, were thoroughly examined. The symposia highlighted the significance of fostering collaboration and continuous learning through a multidisciplinary approach. This initiative should be relevant to healthcare professionals, researchers, and policymakers striving to enhance patient outcomes in tongue cancer care through innovative collaboration.
RESUMO
BACKGROUND: Gene therapy is a promising treatment for protein deficiency disorders such as hemophilia B. However, low tissue selectivity and efficacy are limitations of systemic vector delivery. The authors hypothesized that selective transfection of rat superficial inferior epigastric artery flaps could provide systemic delivery of coagulation factor IX, preventing the need for systemic vector administration. METHODS: Minicircle DNA containing green fluorescent protein, firefly luciferase, and human coagulation factor IX was created. Vector constructs were validated by transfecting adipose-derived stromal cells isolated from Wistar rat superficial inferior epigastric artery flaps and evaluating transgene expression by fluorescence microscopy, bioluminescence, and enzyme-linked immunosorbent assay. Minicircle DNA luciferase (10 and 30 µg) was injected into murine (wild-type, C57/BL/6) inguinal fat pads (n = 3) and followed by in vivo bioluminescence imaging for 60 days. Wistar rat superficial inferior epigastric artery flaps were transfected with minicircle DNA human coagulation factor IX (n = 9) with plasma and tissue transgene expression measured by enzyme-linked immunosorbent assay at 2 and 4 weeks. RESULTS: Transfected adipose-derived stromal cells expressed green fluorescent protein for 30 days, luciferase for 43 days, and human coagulation factor IX (21.9 ± 1.2 ng/ml) for 28 days in vitro. In vivo murine studies demonstrated dose-dependence between minicircle DNA delivery and protein expression. Ex vivo rat superficial inferior epigastric artery flap transfection with minicircle DNA human coagulation factor IX showed systemic transgene expression at 2 (266.6 ± 23.4 ng/ml) and 4 weeks (290.1 ± 17.1 ng/ml) compared to control tissue (p < 0.0001). CONCLUSIONS: Rat superficial inferior epigastric artery flap transfection using minicircle DNA human coagulation factor IX resulted in systemic transgene detection, suggesting that selective flap or angiosome-based tissue transfection may be explored as a treatment for systemic protein deficiency disorders such as hemophilia B.
Assuntos
DNA/genética , Fator IX/genética , Células Estromais/citologia , Retalhos Cirúrgicos/irrigação sanguínea , Animais , Células Cultivadas , Fator IX/metabolismo , Vetores Genéticos , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Modelos Animais , Ratos , Ratos WistarRESUMO
After mastectomy, breast reconstruction is increasingly performed using autologous tissue with the aim of improving quality of life. During this procedure, autologous tissue is excised, relocated, and reattached using microvascular anastomoses at the site of the extirpated breast. The period during which the tissue is ex vivo may allow genetic modification without any systemic exposure to the vector. Could such access permit delivery of therapeutic agents using the tissue flap as a vehicle? Such delivery may be more targeted and oncologically efficient than systemic therapy, and avoid systemic complications. The cytokine IFNγ has antitumor effects, and systemic toxicity could be circumvented by localized delivery of the IFNγ gene via gene therapy to autologous tissue used for breast reconstruction, which then releases IFNγ and exerts antitumor effects. In a rat model of loco-regional recurrence (LRR) with MADB-106-Luc and MAD-MB-231-Luc breast cancer cells, autologous tissue was transduced ex vivo with an adeno-associated viral vector encoding IFNγ. The "Therapeutic Reconstruction" released IFNγ at the LRR site and eliminated cancer cells, significantly decreased tumor burden, and increased survival compared with sham reconstruction (P <0.05). Mechanistically, localized IFNγ immunotherapy stimulated M1 macrophages to target cancer cells within the regional confines of the modified tumor environment. This concept of "Therapeutic Breast Reconstruction" using ex vivo gene therapy of autologous tissue offers a new application for immunotherapy in breast cancer with a dual therapeutic effect of both reconstructing the ablative defect and delivering local adjuvant immunotherapy.
Assuntos
Neoplasias da Mama/cirurgia , Terapia Genética/métodos , Imunoterapia/métodos , Interferon gama/imunologia , Mamoplastia/métodos , Fragmentos de Peptídeos/imunologia , Animais , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Humanos , Ratos , Ratos Endogâmicos F344RESUMO
The effect of adipose tissue on inductive adipogenesis within Matrigel (BD Biosciences) was assessed by using a murine chamber model containing a vascular pedicle. Three-chamber configurations that varied in the access to an adipose tissue source were used, including sealed- and open-chamber groups that had no access and limited access, respectively, to the surrounding adipose tissue, and a sealed-chamber group in which adipose tissue was placed as an autograft. All groups showed neovascularization, but varied in the amount of adipogenesis seen in direct relation to their access to preexisting adipose tissue: open chambers showed strong adipogenesis, whereas the sealed chambers had little or no adipose tissue; adipogenesis was restored in the autograft chamber group that contained 2- to 5-mg fat autografts. These showed significantly more adipogenesis than the sealed chambers with no autograft ( p < 0.01). Autografts with 1mg of fat were capable of producing adipogenesis but did so less consistently than the larger autografts. These findings have important implications for adipose tissue engineering strategies and for understanding de novo production of adipose tissue.
Assuntos
Adipogenia , Tecido Adiposo , Materiais Biocompatíveis , Comunicação Celular , Diferenciação Celular , Colágeno , Laminina , Proteoglicanas , Tecido Adiposo/citologia , Tecido Adiposo/transplante , Animais , Combinação de Medicamentos , Camundongos , Neovascularização Fisiológica , Transplante AutólogoRESUMO
BACKGROUND: Sutureless microvascular anastomosis has great translational potential to simplify microvascular surgery, shorten operative times, and improve clinical outcomes. The authors developed a transient thermoreversible microvascular stent using a poloxamer to maintain vessel lumen patency before application of commercially available adhesives to seal the anastomosis instead of sutures. Despite technical success, human application necessitates bovine serum albumin removal from existing formulations; rapid poloxamer transition between states; and increased stiffness for reliable, reproducible, and precise microvascular approximation. METHODS: Two commercially available poloxamers were used in this study (P407 and P188). After removing bovine serum albumin, each poloxamer was tested at varying concentrations either alone or in combination to determine the optimal preparation for sutureless microvascular anastomosis. Transition temperature and formulation stiffness were tested in vitro by rheometry, with the most promising combinations tested in an established in vivo model. RESULTS: Increasing poloxamer concentration resulted in an increase in stiffness and decrease in transition temperature. Pure P188 without bovine serum albumin, dissolved in phosphate-buffered saline to a 45% concentration, demonstrated desirable rheologic behavior, with precise gel transition and increased gel stiffness compared with our previous formulation of 17% P407 (96 kPa versus 10 kPa). These characteristics were optimal for microsurgical intravascular use, offering surgical precision and control between liquid and solid states, depending on the surgically controlled local temperature. CONCLUSIONS: Use of 45% P188 without bovine serum albumin demonstrated optimal rheologic and translational properties as a microvascular stent for sutureless anastomosis. Rapid transition, increased stiffness, and safety profile demonstrate safe translational application for human clinical trials.
Assuntos
Aorta Torácica/cirurgia , Microcirurgia/métodos , Poloxâmero , Stents , Técnicas de Sutura , Procedimentos Cirúrgicos Vasculares/métodos , Anastomose Cirúrgica/métodos , Animais , Bovinos , Modelos Animais de Doenças , Masculino , Desenho de Prótese , Ratos , Ratos Sprague-Dawley , TemperaturaRESUMO
Engineering of small diameter (<6mm) vascular grafts (SDVGs) for clinical use remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1-4MPa, strengths from 1-5MPa, and max strains from 300-500%. Permeability of the HFMs varies from 0.5-3.5×10(-6)cm/s, while burst pressure varies from 25 to 35psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications.
Assuntos
Polímeros/química , Polímeros/farmacologia , Transplantes/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Prótese Vascular , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Elasticidade , Elastômeros , Células Endoteliais/efeitos dos fármacos , Humanos , Membranas Artificiais , Células-Tronco Mesenquimais/efeitos dos fármacos , Permeabilidade/efeitos dos fármacos , Poliésteres/química , Porosidade , Engenharia Tecidual/métodosRESUMO
BACKGROUND: Percutaneous needle fasciotomy (PNF) is a minimally invasive technique used to manage Dupuytren's contracture. We compared outcomes of PNF versus open fasciectomy (OF) to examine the suitability of PNF in Australia. METHOD: A retrospective cohort study using two questionnaires regarding Dupuytren's treatment was used to assess patients with uncomplicated primary disease. The primary outcomes were immediate and medium-term correction of contracture (2-year mean follow-up to time of survey). Secondary outcomes were patient satisfaction and complications including tendon/nerve injury, infection, skin necrosis and vascular damage. RESULTS: One hundred fifty-five out of 191 surveys were returned (81%). The final analysis included 125 cases (65%), 73 PNF and 52 OF. No significant differences were observed between both groups with regards to follow-up time, gender, smoking status, co-morbidities or preoperative deformity grade. No significant differences were observed in terms of immediate or medium-term deformity correction, tendon/nerve injury or circulatory complications. The postoperative infection rate was higher with OF, with these patients 7.57 (95% confidence interval 1.56, 36.77; P = 0.01) times as likely to have a postoperative infection as patients undergoing PNF. A higher number of patients who underwent PNF were told that they would require another operation (30% versus 12%; P = 0.02). Satisfaction scores were similar (OF 33.2 versus PNF 32.6; P = 0.82). CONCLUSION: The OF and PNF procedures provide comparable deformity correction for uncomplicated primary Dupuytren's disease in the immediate perioperative period. The reduced side effect profile of PNF should prompt surgeons to consider incorporating it in their practice for the first-line management of uncomplicated primary Dupuytren's disease.
Assuntos
Contratura de Dupuytren/cirurgia , Fasciotomia , Agulhas , Procedimentos Ortopédicos/instrumentação , Satisfação do Paciente , Idoso , Contratura de Dupuytren/fisiopatologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Recuperação de Função Fisiológica , Estudos Retrospectivos , Inquéritos e Questionários , Fatores de Tempo , Resultado do TratamentoRESUMO
Modern imaging techniques are an essential component of preoperative planning in plastic and reconstructive surgery. However, conventional modalities, including three-dimensional (3D) reconstructions, are limited by their representation on 2D workstations. 3D printing, also known as rapid prototyping or additive manufacturing, was once the province of industry to fabricate models from a computer-aided design (CAD) in a layer-by-layer manner. The early adopters in clinical practice have embraced the medical imaging-guided 3D-printed biomodels for their ability to provide tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. With increasing accessibility, investigators are able to convert standard imaging data into a CAD file using various 3D reconstruction softwares and ultimately fabricate 3D models using 3D printing techniques, such as stereolithography, multijet modeling, selective laser sintering, binder jet technique, and fused deposition modeling. However, many clinicians have questioned whether the cost-to-benefit ratio justifies its ongoing use. The cost and size of 3D printers have rapidly decreased over the past decade in parallel with the expiration of key 3D printing patents. Significant improvements in clinical imaging and user-friendly 3D software have permitted computer-aided 3D modeling of anatomical structures and implants without outsourcing in many cases. These developments offer immense potential for the application of 3D printing at the bedside for a variety of clinical applications. In this review, existing uses of 3D printing in plastic surgery practice spanning the spectrum from templates for facial transplantation surgery through to the formation of bespoke craniofacial implants to optimize post-operative esthetics are described. Furthermore, we discuss the potential of 3D printing to become an essential office-based tool in plastic surgery to assist in preoperative planning, developing intraoperative guidance tools, teaching patients and surgical trainees, and producing patient-specific prosthetics in everyday surgical practice.
RESUMO
A case of melanoma with rhabdomyoblastic differentiation is presented in the context of the previously reported cases. The emerging literature seeking to identify the molecular basis of rhabdoid and rhabdomyoblastic differentiation, as well as their poor prognosis, is reviewed. The combination of a diverse range of morphology and the potential for spontaneous primary tumor regression, despite metastasis, makes the accurate diagnosis of melanoma challenging. Histopathology review is often recommended in these cases, as is referral to a specialized cancer center for discussion in a multidisciplinary meeting. Improved recognition of this rare pattern of melanoma morphology may provide the means for omics-based techniques to identify novel therapeutic targets to improve the prognostic outlook for these patients.
Assuntos
Diagnóstico Diferencial , Melanoma/diagnóstico , Tumor Rabdoide/diagnóstico , Neoplasias Cutâneas/diagnóstico , Biomarcadores Tumorais/análise , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-IdadeRESUMO
SUMMARY: Since the serendipitous discovery that implanted polymers cause sarcomas in rats, much research has been conducted to prove or disprove a link between silicone breast implants and/or polymer-based materials and breast cancer. In light of an initial report that 35% of rats implanted with a variety of polymers developed fibrosarcomas, we report a case of primary angiosarcoma found in a patient presenting with bilateral rupture of gel-filled breast implants.
RESUMO
BACKGROUND: Locally advanced head and neck cancer often requires wide resections of the cheek and parotid gland, and in an ageing population preferred reconstructive options aim to avoid lengthy operating times or high risk surgery. While most large parotid defects traditionally require free flap reconstruction, we describe a new and versatile locoregional flap that has been shown to be reliable, simple and safe. METHODS: We describe the cervico-submental (CSM) keystone-design perforator island flap for head and neck reconstruction, including an analysis of 33 consecutive patients with a range of head and neck defects. The flap was raised based on perforators of the external carotid artery and its branches, and designed to overlay the C2/C3 dermatomes (an aide memoire for flap design). The indications, and surgical technique are described. RESULTS: In 33 consecutive patients, no major complications were encountered. Five patients developed superficial infections, one developed post-operative bleeding and one patient developed partial tip necrosis. Theatre time was considerably shorter than our alternative reconstructive options. CONCLUSION: The CSM keystone-design perforator island flap is a novel and versatile flap, which can be used in a range of advanced cheek and parotidectomy defects, and may enable improved surgical management in an increasingly elderly and high-risk population.
Assuntos
Neoplasias de Cabeça e Pescoço/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Hemorragia Pós-Operatória/etiologia , Neoplasias Cutâneas/cirurgia , Retalhos Cirúrgicos , Idoso , Idoso de 80 Anos ou mais , Carcinoma Basocelular/cirurgia , Carcinoma de Célula de Merkel/cirurgia , Carcinoma de Células Escamosas/cirurgia , Feminino , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/secundário , Humanos , Masculino , Melanoma/cirurgia , Pessoa de Meia-Idade , Duração da Cirurgia , Procedimentos de Cirurgia Plástica/efeitos adversos , Estudos Retrospectivos , Neoplasias Cutâneas/patologia , Retalhos Cirúrgicos/efeitos adversos , Infecção da Ferida Cirúrgica/etiologiaRESUMO
BACKGROUND: Radical inguinal lymphadenectomy (RIL) for bulky metastatic melanoma and non-melanoma skin cancers of the inguinal region, while shown to improve morbidity and survival oncologically, can result in substantial morbidity from wound complications. Skin defects cannot be closed primarily and the substantial dead space predisposes to seroma, wound dehiscence and infection. Despite the clear need for reconstructive options, extended series describing reconstruction of large inguinal defects in this setting have not been reported. METHODS: A prospectively entered, retrospectively reviewed study of 20 consecutive patients undergoing quadriceps keystone island flaps (QKIF) for the closure of complicated inguinal defects is described. RESULTS: There was 100% flap survival, with no partial or complete flap losses. A reduction in wound breakdown/dehiscence from reported rates was seen, with four patients (20%) having wound breakdown, compared to double that rate in reported series. Other wound complications comprised six patients (30%) with mild wound infections, seven patients (35%) with seromas and two patients (10%) with haematomas. CONCLUSION: The QKIF is an effective means of reconstructing inguinal defects after RIL, particularly in high-risk patients, and is technically simpler than other reconstructive techniques advocated for this purpose. Furthermore, the QKIF offers patients with advanced disease (where management is primarily palliative) a potentially improved quality of life with reduced operative morbidity.
Assuntos
Virilha/cirurgia , Excisão de Linfonodo/métodos , Melanoma/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Neoplasias Cutâneas/cirurgia , Retalhos Cirúrgicos , Adulto , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Feminino , Humanos , Tempo de Internação , Excisão de Linfonodo/efeitos adversos , Masculino , Melanoma/epidemiologia , Pessoa de Meia-Idade , Estudos Prospectivos , Qualidade de Vida , Neoplasias Cutâneas/epidemiologiaRESUMO
UNLABELLED: The redundant tissues of the anterior neck are well suited as a donor site for fasciocutaneous flaps in head and neck reconstruction, with similar skin quality and numerous underlying perforators. However, historic cadaveric research has limited the use of this as a donor site for the design of long and/or large flaps for fear of vascular compromise. The authors undertook an anatomical study to identify the vascular basis for such flaps and have modified previous designs to offer the versatile and reliable superior thyroid artery perforator (STAP) flap. Forty-five consecutive computed tomographic angiograms of the neck were reviewed, assessing the vascular supply of the anterior skin of the neck. Based on these findings, eight consecutive patients underwent head and neck reconstruction using a flap based on the dominant perforator of the region. In all cases, a perforator larger than 0.5 mm was identified within a 2-cm radius of the midpoint of the sternocleidomastoid muscle at its anterior border. This perforator was seen to emerge through the investing layer of deep cervical fascia as a fasciocutaneous perforator and to perforate the platysma on its ipsilateral side of the neck, proximal to the midline. This was seen to be a superior thyroid artery perforator in 89 of 90 sides and an inferior thyroid artery perforator in one case. Eight consecutive patients underwent preoperative imaging and successful flap planning and execution based on this dominant perforator. The superior thyroid artery perforator (STAP) flap demonstrates reliable vascular anatomy and is well suited to reconstruction of a broad range of head and neck defects. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.
Assuntos
Pescoço/irrigação sanguínea , Pescoço/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Retalhos Cirúrgicos/irrigação sanguínea , Idoso , Idoso de 80 Anos ou mais , Artérias , Humanos , Pessoa de Meia-Idade , Glândula Tireoide/irrigação sanguíneaRESUMO
Intraoperative frozen section and Mohs' micrographic surgery (MMS) are two techniques used to ensure oncological clearance without resorting to unnecessarily wide margins that might compromise reconstructive options for definitive wound closure. In addition to some technical issues, these techniques are suboptimal for resection of tumours such as melanoma, where specific tissue margins at histopathology are required to ensure minimal risk of local recurrence. We describe a technique that minimizes the amount of tissue excised and uses definitive paraffin sections interpreted in a pathology laboratory in order to delay reconstruction until after clear oncologic margins are obtained. This 'delayed reconstruction after pathology evaluation (DRAPE)' technique is particularly directed at extensive and complicated skin lesions, located in areas of the body that can be difficult to reconstruct and are prone to disfigurement and/or loss of function. A review of the literature is undertaken, establishing the role of each technique in achieving clear surgical margins. A case example is presented, highlighting the role of the DRAPE approach. The DRAPE technique is presented as a useful option for high-risk lesions, especially within aesthetically sensitive regions or for complex reconstructions, and when reconstruction can be reasonably delayed while tumour clearance is established.
Assuntos
Melanoma/patologia , Melanoma/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/cirurgia , Retalhos Cirúrgicos , Feminino , Humanos , Pessoa de Meia-Idade , Fatores de TempoRESUMO
BACKGROUND: Use of autologous tissue is ideal in breast reconstruction; however, insufficient donor tissue and surgical and donor-site morbidity all limit its use. Tissue engineering could provide replacement tissue, but only if vascularization of large tissue volumes is achievable. The authors sought to upscale their small-animal adipose tissue-engineering models to produce large volumes of tissue in a large animal (i.e., pig). METHODS: Bilateral large-volume (78.5 ml) chambers were inserted subcutaneously in the groin enclosing a fat flap (5 ml) based on the superficial circumflex iliac pedicle for 6 (n = 4), 12 (n = 1), and 22 weeks (n = 2). Right chambers included a poly(L-lactide-co-glycolide) sponge. Other pedicle configurations, including a vascular pedicle alone (n = 2) or in combination with muscle (n = 2) or a free fat graft (n = 2), were investigated in preliminary studies. Serial assessment of tissue growth and vascularization by magnetic resonance imaging was undertaken during growth and correlated with quantitative histomorphometry at chamber removal. RESULTS: All chambers filled with new tissue by 6 weeks, vascularized by the arteriovenous pedicle. In the fat flap chambers, the initial 5 ml of fat expanded to 25.9 ± 2.4, 39.4 ± 3.9, and 56.5 ml (by magnetic resonance imaging) at 6, 12, and 22 weeks, respectively. Adipose tissue volume was maintained up to 22 weeks after chamber removal (n = 2), including one where the specimen was transferred on its pedicle to an adjacent submammary pocket. CONCLUSION: The first clinically relevant volumes of tissue for in situ and remote breast reconstruction have been formed with implications for scaling of existing tissue-engineering models into human trials.
Assuntos
Tecido Adiposo/irrigação sanguínea , Tecido Adiposo/transplante , Mamoplastia/métodos , Músculo Esquelético/transplante , Neovascularização Fisiológica/fisiologia , Retalhos Cirúrgicos/irrigação sanguínea , Engenharia Tecidual/métodos , Tecido Adiposo/patologia , Animais , Proliferação de Células , Cultura em Câmaras de Difusão , Endotélio Vascular/patologia , Imageamento por Ressonância Magnética , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/patologia , Cimento de Policarboxilato , Próteses e Implantes , Retalhos Cirúrgicos/patologia , SuínosRESUMO
BACKGROUND: Tissue engineering of patient-specific adipose tissue has the potential to revolutionize reconstructive surgery. Numerous models have been described for the production of adipose tissue with success in the short term, but little has been reported on the stability of this tissue-engineered fat beyond 4 months. METHODS: A murine model of de novo adipogenesis producing a potentially transplantable adipose tissue flap within 4 to 6 weeks was developed in the authors' laboratory. In this study, the authors assess the ability of three-chamber (44-microl volume) configurations shown to be adipogenic in previous short-term studies (autograft, n = 8; open, n = 6; fat flap, n = 11) to maintain their tissue volume for up to 12 months in vivo, to determine the most adipogenic configuration in the long term. RESULTS: Those chambers having the most contact with existing vascularized adipose tissue (open and fat flap groups) showed increased mean adipose tissue percentage (77 +/- 5.6 percent and 81 +/- 6.9 percent, respectively; p < 0.0007) and volume (12 +/- 6.8 microl and 30 +/- 14 microl, respectively; p < 0.025) when compared with short-term controls and greater adipose tissue volume than the autograft (sealed) chamber group (4.9 +/- 5.8 microl; p = 0.0001) at 1 year. Inclusion of a vascularized fat flap within the chamber produced the best results, with new fat completely filling the chamber by 1 year. CONCLUSIONS: These findings demonstrate that fat produced by tissue engineering is capable of maintaining its volume when the appropriate microenvironment is provided. This has important implications for the application of tissue-engineering techniques in humans.