Chorioallantoic Membrane Angiogenesis Model for Tissue Engineering: a New Twist on a Classic Model

Tissue Engineering. Jun, 2003  |  Pubmed ID: 12857412

Tissue-engineering (TE) applications include the isolation, culture, and seeding of cells into a suitable matrix or scaffold before in vivo transplantation. After transplantation, vascularization of the scaffold is a principal limiting factor for cell viability for the first 6-8 days posttransplantation. A model for systematic analysis of this process has been developed. Fertilized White Leghorn eggs were incubated (at 37.8 degrees C in 60% relative humidity) and opened on day 3 of incubation. Preadipocyte-seeded fibrin constructs were implanted in a specially designed plastic cylinder and placed through the opening on the surface of the chorioallantoic membrane (CAM) on day 8 of incubation. Vascularization of the constructs by chorioallantoic blood vessels was assessed for up to 8 days posttransplantation. The survival rate for embryos receiving transplanted constructs was about 90%. Histology confirmed transplant cell viability at day 4 posttransplantation and vascularization of the constructs by avian endothelial cells began at this time. A new in vivo model to study the effect of angiogenesis in TE constructs, including assessments of viability, proliferation, and differentiation of transplanted cells and biomaterial properties, is presented. Advantages include easy access to the vascular network of the CAM, lack of immunocompetence, low costs, and avoidance of animal experiments.

Unusual Explosive Growth of a Squamous Cell Carcinoma of the Scalp After Electrical Burn Injury and Subsequent Coverage by Sequential Free Flap Vascular Connection--a Case Report

BMC Cancer. 2005  |  Pubmed ID: 16309562

Squamous cell carcinomos may arise from chronic ulcerating wounds in scars, most commonly postburn scars. Tumour growth usually takes place over months to years. Localization on the scalp is a relatively rare condition.

Tissue Engineering of Injectable Muscle: Three-dimensional Myoblast-fibrin Injection in the Syngeneic Rat Animal Model

Plastic and Reconstructive Surgery. Oct, 2006  |  Pubmed ID: 17016175

Surgical treatment of skeletal muscle loss resulting from trauma, tumor ablation, or inborn tissue defects is hampered by the scarcity of functional substitute tissue. By using techniques of tissue engineering, reconstitution of skeletal muscle defects might become a more viable option. However, it is necessary to develop an adequate, practical method for delivering myoblasts within a three-dimensional scaffold in vivo. The aim of this study was to create and evaluate a novel method for the transfer of myoblasts with clinically approved components within a three-dimensional matrix.

Engineering of Adipose Tissue by Injection of Human Preadipocytes in Fibrin

Aesthetic Plastic Surgery. May-Jun, 2007  |  Pubmed ID: 17380359

Despite efforts of plastic surgeons in recent years to discover new alternatives, the techniques currently used for restoration of soft tissue defects still have disadvantages. The gold standard for soft tissue reconstruction remains autologous pedicled/free tissue transfer. This technique often results in high rates of operative morbidity and donor site deformity. Results obtained by autologous fat tissue transfer usually are disappointing because of a high graft resorption rate with unpredictable outcomes. Different tissue engineering approaches have been used in the past to generate adipose tissue. However, long-term results in terms of volume persistence have been disappointing.

Implantation of VEGF Transfected Preadipocytes Improves Vascularization of Fibrin Implants on the Cylinder Chorioallantoic Membrane (CAM) Model

Minimally Invasive Therapy & Allied Technologies : MITAT : Official Journal of the Society for Minimally Invasive Therapy. 2007  |  Pubmed ID: 17573620

The successful substitution or augmentation of soft tissues by implantation of three dimensional cell constructs, consisting of human preadipocytes and fibrin glue as a carrier matrix, requires a rapid and homogeneous vascularization of the whole implant in order to provide a sufficient blood supply of centrally situated cells. Previous investigations have shown that under in vivo conditions primary human preadipocytes induce vascularization of fibrin matrices by secretion of several growth factors, such as VEGF and bFGF. The current study investigates whether vascularization of implants can be improved by transplantation of preadipocytes following transfection with a VEGF-vector. Transfection was performed by electroporation with an pCMX-GFP and pCMX-VEGF165 vector. Transfection efficiency (GFP expression) and VEGF expression were determined in vitro by FACS analysis and VEGF immunoassay, respectively. In vivo investigations to determine the vascularization of the implants were performed on the cylinder chorioallantoic membrane (CAM). Four million VEGF transfected cells were transferred within a fibrin matrix onto the CAM on the 7(th) day of incubation and after 8 days the vascularization of the implant was histologically examined and evaluated by means of a computer-assisted image analysis program. Transfection of preadipocytes with the GFP vector by electroporation yielded transfection efficiencies between 12% and 41% of surviving cells. Results of the VEGF immunoassay demonstrated that VEGF expression was significantly higher following transfection. Investigations on the CAM outlined a significantly higher rate of vascularization in the transfected vs. control population. Our investigations demonstrate that primary human preadipocytes can be successfully transfected by electroporation with a VEGF vector. The enhanced VEGF expression on transfected cells results in an increase of vascularization of the cell constructs on the CAM.

Changes in the Aging Upper Lip--a Photomorphometric and MRI-based Study (on a Quest to Find the Right Rejuvenation Approach)

Journal of Plastic, Reconstructive & Aesthetic Surgery : JPRAS. Oct, 2008  |  Pubmed ID: 18639513

A lack of scientific data about the complex three dimensional changes in relation to the rest of the face is the reason for the multitude of rejuvenation approaches to the aging upper lip. In this study the underlying anatomic changes and facial proportions of the senile upper lip are scientifically evaluated for the first time.

Evidence-based Plastic Surgery: Controlled Trials in Three Plastic Surgical Journals (1990-2005)

Annals of Plastic Surgery. Aug, 2008  |  Pubmed ID: 18650619

Although a myriad of original articles is published annually in plastic surgical journals, assessment of the level of evidence-based medicine has rarely been conducted. A hand search was conducted identifying randomized controlled trials (RCTs) and controlled clinical trials in 3 plastic surgical journals from 1990-2005. The quality of reporting was assessed and additional parameters investigated including report of statistical significance, type of institution, and country affiliation of the first author. Of the 9428 original articles that were analyzed, 172 and 139 articles met the inclusion criteria for RCTs and controlled clinical trials, respectively. Fifty-nine RCTs reported on successful double-blinding with only 20 RCTs reporting the allocation concealment appropriately. Description of participant drop-outs was detected in 64 RCTs and a statistically significant result was reported in 118 RCTs. The annual publication of controlled trials has increased over the last 16 years, with the majority of controlled trials being from North-America and Europe. Execution and publication of controlled trials has increased in the plastic surgical literature. However, the quality of reporting deserves improvement.

The Extended Pectoralis Major Flap for Reconstruction of the Upper Posterior Chest Wall and Axilla

The Journal of Thoracic and Cardiovascular Surgery. Sep, 2008  |  Pubmed ID: 18805291

C-reactive Protein: How Conformational Changes Influence Inflammatory Properties

Cell Cycle (Georgetown, Tex.). Dec, 2009  |  Pubmed ID: 19887916

Recent evidence suggests that the prototypic acute phase reactant C-reactive protein (CRP) is not only a marker but also a potential contributor to inflammatory diseases. CRP belongs to the family of pentraxins and as such consists of five identical non-covalently linked subunits. Contradictory data on the characteristics of CRP as either being pro- or anti-inflammatory may be explained by the existence of two conformations of the protein: the circulating native, pentameric CRP (pCRP) and the monomeric isoform (mCRP), formed as a result of a dissociation process of pCRP. In vitro both isoforms exhibit a very distinct inflammatory profile. We recently identified a localized, physiologically relevant pCRP dissociation mechanism by activated platelets and apoptotic cells and showed the deposition of mCRP in inflamed tissue. Here we review the literature on the causal role of pCRP and mCRP in the light of our findings and critically analyze the current controversies around CRP. The novel understanding of the localized dissociation of circulating pentameric CRP to the distinctively pro-inflammatory monomeric CRP allows for a new view on CRP in inflammatory reactions and further highlights mCRP and the pCRP dissociation process as a potential therapeutic target.

Simultaneous Pectoralis Major Myocutaneous Flap Combined with Breast Reduction for Sternal Defect Coverage

Journal of Plastic, Reconstructive & Aesthetic Surgery : JPRAS. Aug, 2009  |  Pubmed ID: 18539551

The pectoralis myocutaneous island flap is a well established technique for tissue reconstruction. In female patients with concomitant breast hypertrophy there may be a simultaneous indication for breast reduction mammoplasty. The inferior pole of the breast and the inframammary fold coincide with the skin island territory of myocutaneous flaps supplied by the thoracoacromial artery.

A New Evaluation Tool for Monitoring Devices and Its Application to Evaluate the Implantable Doppler Probe

Journal of Reconstructive Microsurgery. May, 2010  |  Pubmed ID: 20143302

Evaluation parameters for free flap monitoring devices are used inconsistently, leading to considerable confusion about the quality and applicability of these devices. A comparison of different systems and different clinical series is almost impossible. The ultimate questions that need to be answered are those regarding the efficiency and the effectiveness of the system. A new tool consisting of two simple parameters that sufficiently and comparably describe the quality of monitoring devices is developed. The flap failure reduction rate describes the percentage of saved flaps (effectiveness). The revision success rate describes the efficiency. Literature reevaluation shows inconsistent results, although all authors describe a positive experience. This shows the limited value of the classical parameters. Larger studies have flap failure reduction rates of 5 to 12% (5 to 12% of monitored flaps are saved). Revision success rates of 75 to 90% prove that the system is efficient enough in daily use. Reevaluation of the smaller reported series result in lower parameters, which shows that there is a significant learning curve for this device. The new parameters alleviate the confusion surrounding evaluation of monitoring systems by giving specific information about effectiveness and efficiency. The benefits of the implanted Doppler probe can now be clearly described. However, in several studies the benefit of the system is overrated.

Ten Years Stable Internal Fixation of Metacarpal and Phalangeal Hand Fractures-risk Factor and Outcome Analysis Show No Increase of Complications in the Treatment of Open Compared with Closed Fractures

The Journal of Trauma. Mar, 2010  |  Pubmed ID: 20220420

: Stable internal screw/plating systems for hand fractures have evolved during the last 20 years. The improved versatility leads to the increased use of these materials in open fractures, with the benefit of early mobilization. The aim of this retrospective study is to discern whether the broadening of the indications for these implants is accompanied by increased complication rates.

The Use of the Vacuum-assisted Closure in Microsurgical Reconstruction Revisited: Application in the Reconstruction of the Posttraumatic Lower Extremity

Journal of Reconstructive Microsurgery. Nov, 2010  |  Pubmed ID: 20922656

Introduction of vacuum-assisted closure (VAC) system into clinical practice has revolutionized wound care. Despite its multiple advantages, however, the VAC is only rarely used in the setting of microsurgical reconstruction. Concerns have been the inability to clinically monitor the flap as well the possibility of flap compression by the device. The authors put their postoperative treatment concept of applying the VAC to free flaps to the test by reviewing their experience with this concept in patients undergoing microsurgical reconstruction of posttraumatic lower-extremity soft tissue defects. Twenty-six patients (22 male, 4 female) were included in this study. Use of the implantable Doppler probe allowed for postoperative flap monitoring. Two flap failures were observed, both in patients with peripheral vascular disease. In conclusion, using the VAC device in the setting of microsurgical reconstruction is safe and allows for increased patient comfort.

An in Vivo Engineered Nerve Conduit--fabrication and Experimental Study in Rats

Microsurgery. Jul, 2011  |  Pubmed ID: 21503976

Several types of nerve conduits have been used for peripheral nerve gap bridging. This study investigated the in vivo engineering of a biological nerve conduit and its suitability for nerve gap bridging.

An Integrated Therapy Concept for Reduction of Postoperative Complications After Resection of a Panniculus Morbidus

Obesity Surgery. Apr, 2012  |  Pubmed ID: 22108809

Panniculus morbidus is characterized by an edematous, painful hanging abdominal mass, due to laxity and redundancy of the abdominal skin in morbid obesity, particularly after massive weight loss. Panniculectomy, by wedge resection, is a salvage procedure with high satisfaction rates though associated with high complication rates. Here we investigated the effects of perioperative complex decongestive physical therapy (CDP) on outcome and complication rates.

The Long-term Functional Recovery of Repair of Sciatic Nerve Transection with Biogenic Conduits

Microsurgery. Jul, 2012  |  Pubmed ID: 22434585

The aim of this study was to evaluate long-term regenerative capacity over a 15-mm nerve gap of an autologous nerve conduit, the biogenic conduit (BC), 16 weeks after sciatic nerve transection in the rat.

Comparison of Schwann Cells and Olfactory Ensheathing Cells for Peripheral Nerve Gap Bridging

Cells, Tissues, Organs. Jun, 2012  |  Pubmed ID: 22699447

Introduction: Previously, we introduced the biogenic conduit (BC) as a novel autologous nerve conduit for bridging peripheral nerve defects and tested its regenerative capacity in a short- and long-term setting. The aim of the present study was to clarify whether intraluminal application of regeneration-promoting glial cells, including Schwann cells (SC) and olfactory ensheathing cells (OEC), displayed differential effects after sciatic nerve gap bridging. Material and Methods: BCs were generated as previously described. The conduits filled with fibrin/SC (n = 8) and fibrin/OEC (n = 8) were compared to autologous nerve transplants (NT; n = 8) in the 15-mm sciatic nerve gap lesion model of the rat. The sciatic functional index was evaluated every 4 weeks. After 16 weeks, histological evaluation followed regarding nerve area, axon number, myelination index and N ratio. Results: Common to all groups was a continual improvement in motor function during the observation period. Recovery was significantly better after SC transplantation compared to OEC (p < 0.01). Both cell transplantation groups showed significantly worse function than the NT group (p < 0.01). Whereas nerve area and axon number were correlated to function, being significantly lowest in the OEC group (p < 0.001), both cell groups showed lowered myelination (p < 0.001) and lower N ratio compared to the NT group. Discussion: SC-filled BCs led to improved regeneration compared to OEC-filled BCs in a 15-mm-long nerve gap model of the rat.

Infraareolar Pectoralis Major Myocutaneous Island Flap As Treatment of First Choice for Deep Sternal Wound Infection

Journal of Plastic, Reconstructive & Aesthetic Surgery : JPRAS. Oct, 2012  |  Pubmed ID: 23102609

Deep sternal wound infection (DSWI) is a grave complication of median sternotomy, associated with high morbidity, mortality and escalating treatment costs. There is general consensus that optimal treatment comprises radical debridement followed by coverage with a vascularised flap. However, there is ongoing debate regarding the ideal operative procedure. We present our experience with the infraareolar pectoralis major island myocutaneous flap (PEC-MI flap) as treatment of first choice in DSWI. Following a retrospective chart review, data pertaining to patient demographics, type of cardiac surgery performed, prevalence of known DSWI risk factors, identified pathogens, duration of surgery, flap-related complications, duration of hospital stay and antibiotic therapy, as well as mortality were noted. Additionally, we describe the operative technique and review the relevant literature. Twenty-five patients underwent coverage with the PEC-MI flap in our department. The average age was 69.2 years. Nineteen patients underwent coronary artery bypass surgery, 10 valve replacement, two aortic replacement surgery and one pericardiectomy. In six cases, no internal mammary artery was used in cardiac surgery, in 11 cases one and in seven cases both internal mammary arteries were used. The average duration of surgery was 154.2 min and the average hospital stay was 28.4 days. Complications which required revision surgery were haematoma in three cases, one wound dehiscence and one recurrent infection. Two cases required coverage with an additional regional flap. The PEC-MI flap has been used as flap of first choice in our clinic for treatment of DSWI. It is sufficient to raise the flap unilaterally, and it does not require skin grafting. The combination of immunocompetent bulky muscle tissue used to obliterate the sternal cavity and the large skin paddle enabling a low-tension skin closure allows reliable and efficient treatment of this severe complication.