Collagen Mesh Research Articles

Comparative study between meshes of polyester with collagen and polytetrafluoroethylene in the repair of defects produced in abdominal wall of rats

To study the intraperitoneal use of polyester with collagen and polytetrafluoroethylene meshes in the correction of total ventral wall defects in rats. Thirty two rats were evaluated and divided randomly into four groups and underwent laparotomy and preparation of total defects of the abdominal wall. Next, the correction of the defect with the intraperitoneal placement of the chosen mesh was performed. The rats were submitted to euthanasia at 30 and 90 days after surgery. Were analyzed the macroscopic adhesions and microscopic aspects, and applied stress rupture test All animals showed intraperitoneal adhesions in varying degrees, with no statistical significance difference. There was no difference also between groups in the evaluation of stress rupture tests. On the microscopic aspect, the A30 group had less inflammatory reaction and less formation of granulomas and foreign body reaction that the B30 group, with significant difference. There was no difference in intraperitoneal adhesion and tensile rupture strength among groups. Group B30 presented granulomatous inflammatory reaction at the site of mesh attachment to the wall significantly higher than the A30.

A short-term preservation of human cultured periosteal sheets, osteogenic grafting materials, using a commercial preservation solution containing epigallocatechin-3-gallate (Theliokeep(®)) under hypothermic conditions.

In the past decade, it has increasingly been reported that epigallocatechin-3-gallate (EGCG), a major catechin derivative extracted from Green tea, has various bioactivities, including a cell-protective action on mammalian cells and tissues. In this study, we have tested a commercial preservation solution containing EGCG (Theliokeep(®)) in both two- and three-dimensional cultures of human periosteal sheets, which have been used as an osteogenic grafting material for periodontal regenerative therapy. When periosteal sheets were 3D-cultured on collagen mesh, cell viability was maintained for 2 days using the hypothermic EGCG preservation solution. Replenishment of EGCG solution with 2-day intervals prevented the time-dependent decline in cell viability at 3 days and later. As observed in nonpreserved control cultures, most cells were positive for proliferating cell-nuclear antigen (PCNA) in the cultures preserved at 4°C in the EGCG solution, whereas PCNA-negative cells were increased in the cultures preserved at 4°C in the MesenPRO medium. In periosteal sheets 2D-cultured in plastic dishes, the EGCG solution occasionally was associated with vacuole formation in the cytoplasm, but cells could again expand in the culture medium at 37°C. As observed in the nonpreserved periosteal sheets control, the osteogenic induction upregulated alkaline phosphatase in those cells and tissues preserved in the EGCG solution. The EGCG solution protected cells from the cold shock-induced membrane phospholipid peroxidation. Our data suggest that the EGCG solution acts as an antioxidant to protect periosteal cells from cold shock and preserves cells under chilled conditions. The limited period of preservation time could be expanded by repeating replenishment of the EGCG solution or by optimizing the formula to be more favorable for human periosteal sheets without sacrificing cell viability. This methodology of preserving human cultured periosteal sheets with EGCG would be expected to support and spread the clinical use of regenerative therapy with autologous periosteal sheets.

Two-Layer Tissue Engineered Urethra Using Oral Epithelial and Muscle Derived Cells

We fabricated novel tissue engineered urethral grafts using autologously harvested oral cells. We report their viability in a canine model. Oral tissues were harvested by punch biopsy and divided into mucosal and muscle sections. Epithelial cells from mucosal sections were cultured as epithelial cell sheets. Simultaneously muscle derived cells were seeded on collagen mesh matrices to form muscle cell sheets. At 2 weeks the sheets were joined and tubularized to form 2-layer tissue engineered urethras, which were autologously grafted to surgically induced urethral defects in 10 dogs in the experimental group. Tissue engineered grafts were not applied to the induced urethral defect in control dogs. The dogs were followed 12 weeks postoperatively. Urethrogram and histological examination were done to evaluate the grafting outcome. We successfully fabricated 2-layer tissue engineered urethras in vitro and transplanted them in dogs in the experimental group. The 12-week complication-free rate was significantly higher in the experimental group than in controls. Urethrogram confirmed urethral patency without stricture in the complication-free group at 12 weeks. Histologically urethras in the transplant group showed a stratified epithelial layer overlying well differentiated submucosa. In contrast, urethras in controls showed severe fibrosis without epithelial layer formation. Two-layer tissue engineered urethras were engineered using cells harvested by minimally invasive oral punch biopsy. Results suggest that this technique can encourage regeneration of a functional urethra.

Bonding effectiveness of a new ‘multi-mode’ adhesive to enamel and dentine

ObjectivesSelf-etch adhesives are well adopted in general practice, obviously primarily thanks to their ease of use and fast application time. Nevertheless, phosphoric acid is still often recommended to beforehand etch enamel following a so-called ‘selective’ enamel-etch technique, this in particular when most cavity margins end in enamel. The purpose of this study was to test if a new one-step adhesive can be applied in a multi-mode manner, this following different, either ‘full’ or ‘selective’, self-etch and etch-and-rinse approaches. Specific research hypotheses tested were that prior phosphoric-acid etching did not affect the bonding effectiveness of the one-step adhesive to enamel and dentine, and that the bonding effectiveness to dentine was also not affected when the adhesive was applied either following a ‘dry-bonding’ or ‘wet-bonding’ etch-and-rinse technique. MethodsThe micro-tensile bond strength (μTBS) of the one-step self-etch adhesive G-Bond Plus (GC, Tokyo, Japan; 1-SEA) was measured when it was bonded to bur-cut enamel following either a ‘self-etch’ or an ‘etch-and-rinse’ adhesive protocol, and to bur-cut dentine when applied following either a ‘self-etch’, a ‘dry-bonding’ or a ‘wet-bonding’ etch-and-rinse adhesive protocol. Bond-strength testing was corroborated by ultra-structural analysis of the interfacial interaction at enamel and dentine using transmission electron microscopy (TEM). ResultsPrior phosphoric-acid etching significantly increased the bonding effectiveness of the 1-SEA to enamel. A clearly enhanced micro-retentive surface was revealed by TEM. To dentine, no statistically significant difference in bonding effectiveness was recorded when the 1-SEA was either applied following a self-etch or both etch-and-rinse approaches. The ‘dry-bonding’ etch-and-rinse protocol was significantly more effective than its ‘wet-bonding’ version. TEM however revealed indications of low-quality hybridisation following both etch-and-rinse approaches, in particular in the form of a porous and poorly resin-infiltrated collagen mesh. ConclusionsWhile phosphoric-acid etching definitely improved bonding of the one-step self-etch adhesive to enamel, one should be more careful with additional phosphoric-acid etching of dentine. Although the bond strength was not reduced, the resultant adhesive interface appeared ultra-structurally more vulnerable to biodegradation.

Acellular dermal collagen mesh (Permacol®) for thoracic wall reconstruction

Acellular dermal collagen mesh (Permacol®) for thoracic wall reconstruction

Instant Abdominal Wall Reconstruction with Biologic Mesh following Resection of Locally Advanced Colonic Cancer

We present a case of immediate abdominal wall reconstruction with biologic mesh following the resection of locally advanced colonic cancer. The tumor in the right colon did not respond to neoadjuvant chemotherapy. Surgical enbloc excision, including excision of the invasion in the abdominal wall, was achieved, and the defect was reconstructed with porcine dermal collagen mesh. The patient was discharged with no complication, and adaptation of the mesh was excellent at the six-month followup.

Postimplant intraperitoneal behavior of collagen-based meshes followed by laparoscopy

When repairing an abdominal wall defect, sometimes a prosthetic mesh needs to be placed directly on the parietal peritoneum. Although the standard mesh for this purpose is the laminar implant expanded polytetrafluoroethylene (PTFE), it is gradually being replaced by the laminar collagen-based meshes. This study was designed to assess the intraperitoneal behavior of three of these biomeshes, mainly in terms of their susceptibility to adhesion formation. Two 3-cm×3-cm fragments of prosthetic material were placed on the parietal peritoneum in male New Zealand White rabbits in the following combinations: PTFE and CollaMend(®), PTFE and Permacol(®), or PTFE and Surgisis(®). The meshes were fixed at the four corners with individual 4/0 polypropylene sutures. Adhesion formation was quantified by sequential laparoscopy and image analysis performed at 3, 7, 14, and 90days postimplant. All animals were killed at 90days and the mesh specimens were subjected to microscopy and immunohistochemistry. Intensely vascularized adhesions to all the implants were observed, although Surgisis showed the lowest percentage of adhesions at each follow-up time. Adhesions had stabilized by 7-14days. The PTFE meshes were enveloped by a layer of macrophages and connective tissue, bounded by a monolayer of mesothelial cells. Permacol and CollaMend showed similar histological behavior, including cell ingrowth through their fenestrations with no signs of degradation detected at 90days. In contrast, the Surgisis mesh at 90days was practically replaced with neoformed tissue. No difference in susceptibility to adhesion formation was noted in the crosslinked collagen meshes compared to PTFE meshes. The noncrosslinked collagen mesh Surgisis showed the best behavior in that it induced fewer adhesions. Ninety days after implant, a more intense macrophage response was observed in CollaMend and Permacol than in PTFE or Surgisis.

The abdominal compartment syndrome: review, experience report and description of an innovative biological mesh application

Intra abdominal hypertension (IAH) is defined as an intra-abdominal pressure (IAP) >12 mmHg. Abdominal compartment syndrome (ACS) is defined as an IAP above 20 mmHg with evidence of organ dysfunction/failure. The real incidence of the ACS is not clear, because there are few perspective studies. The origin of ACS can be divided into retroperitoneal, intraperitoneal, parietal and intestinal, and the diagnostic algorithm includes base and toxicological laboratory examinations, thorax X-ray, abdomen X-ray, abdomen TC, peritoneal washing, abdomen ultrasonography, diagnostic laparoscopy, and measurement of IAP. To allow a suitable decompression and avoid the damages to the abdominal organs, abdominal wall normally is not sutured primarily but secondarily and there are many methods of temporary closing: absorbable net, non-absorbable nets, 'Bogota bag', 'vacuum pack ice', gradual approximation of side cutaneous edges on the half-way line with permanence of an ample ventral hernia that could be subsequently repaired, and the use of 'skin expanders'. Since January 2000, until December 2008, eight patients were submitted to laparostomy, four of them for re-laparotomy, with mortality incidence of 37.5%. The defective size to fill was on the average 300 cm as reported by Bradley and Bradley (J Clin Invest 26:1010-1015, 1947). The abdominal wall reconstruction was performed using ample muscle edges derived from the slip in medial sense of the rectus muscle of the abdomen 'unmoored' through an incision 1 cm distant from semi-lunar line, and using absorbable prosthesis to cover the solution of continuity, thus allowing the closing of defects over 30 cm. We have found median post surgical hernia in one patient corrected in accordance with the time using polypropylene prosthesis. In one patient with parietal disaster and multiple traumatic splanchnic ruptures, we have used a pure pork-derived acellular collagen mesh (Permacol(®)) to close the wound, leaving enough space between fascia extremities, to solve the IAP. The employment of ample muscle edges represents the ideal solution in the reconstruction of the abdominal walls after laparotomic operations, offering a valid dynamic support preferable in comparison with the employment of alloplastic material. In consideration of the limits of this technique in the enormous parietal disaster-ACS treatment, we describe a new kind of innovative mesh application (Permacol(®)), most often used for parietal disaster or enormous incisional hernias, which can easily be preferred to dual mesh prosthesis, having a better biological profile and no capacity to produce intestinal adherences.

Assembly of collagen fibril meshes using gold nanoparticles functionalized with tris(hydroxymethyl)phosphine‐alanine as multivalent cross‐linking agents

We report on the use of tris(hydroxymethyl)phosphine-alanine (THPAL) functionalized gold nanoparticles as a multivalent cross-linking agent to assemble collagen fibrils into a mesh-like structure. Atomic force microscopy (AFM) was used for characterization of the structure after adsorption onto an atomically flat mica substrate, revealing a mesh-like construct in which the collagen fibrils and the gold nanoparticles interact to form interconnected nodes measuring from 100 to 500 nm. As expected, the density of the collagen mesh can be increased with a higher initial concentration of gold nanoparticles. The maximum thickness of the meshes (∼ 20 nm) obtained through cross-sectional height measurements confirms that the adsorbed structure consists of a single layer of collagen fibrils/gold nanoparticles assembled in two-dimensions. We propose that the capability of gold nanoparticles functionalized with the THPAL to bind to several collagen fibrils combined with the large persistence length of the fibrils, which was reported to be in the hundreds of nanometer range, are determinant factors for the preferential 2D growth of the mesh in solution.

The effect of biological and synthetic meshes on vaginal smooth muscle cell proliferation

To compare the effects of polypropylene mesh or porcine dermal acellular collagen matrix mesh with and without estradiol supplementation on vaginal smooth muscle cells (VaSMC) proliferation. Under in vitro culture conditions, VaSMC proliferation was significantly higher in the porcine dermal acellular collagen matrix mesh exposed cells compared to the type I polypropylene mesh exposed cells (relative cell number, mean ± SD, 0.27 ± 0.03 vs. 0.21 ± 0.01, P = 0.03). Under estradiol supplementation cell proliferation in the porcine mesh exposed cells remained significantly higher compared to the polypropylene mesh exposed cells (relative cell number, mean ± SD, 0.27 ± 0.04 vs. 0.15 ± 0.03, P < 0.01). The decreased rate of erosion found with the utilization of biological absorbable mesh in vaginal reconstructive surgery may partially be explained by the significantly increased VaSMC proliferation with porcine dermal acellular collagen mesh compared to polypropylene mesh.

Parastomal hernia repair outcomes in relation to stoma site with diisocyanate cross-linked acellular porcine dermal collagen mesh

Biologic meshes are increasingly used in parastomal hernia repair. This study evaluates the efficacy and safety of diisocyanate cross-linked acellular porcine dermal collagen mesh for parastomal hernia repair, with particular reference to the relationship of the stoma site to the rectus sheath. Hernias were repaired via a lateral approach, with onlay placement of the biologic mesh. A retrospective case note review and analysis of clinical outcomes was performed. The relationship of the stoma to the rectus sheath was determined by abdominal computed tomography (CT) and intraoperative findings. Over a 16-month period, 27 consecutive patients, median age 72 years, underwent parastomal hernia repair utilising onlay biologic mesh to reinforce the external oblique aponeurosis. There were 20 paracolostomy and seven paraileostomy hernias. Eleven stomas passed through the rectus sheath and 16 were lateral to it. Recurrences occurred in 3 of 11 stomas within and 12 of 16 stomas lateral to the rectus sheath (P = 0.022). The median time to recurrence was 10.1 months. The median follow up of patients without recurrence was 16.6 months (range 0.2-39.3). There was one perioperative death. One patient developed a superficial post-operative abscess that was managed conservatively, but there were no complications related to the biologic mesh and no mesh required removal. For parastomal hernias within the rectus sheath, diisocyanate cross-linked porcine dermal collagen mesh onlay repair gives good results and is safe to use. Repair of a parastomal hernia where the stoma is lateral to the rectus sheath has a significantly higher risk of recurrence and is not recommended.

Mechanical properties of cross‐linked collagen meshes after human adipose derived stromal cells seeding

The main goal of this study was to evaluate the potential of collagen meshes derived from porcine dermis as scaffolds for repairing pelvic organ prolapses. Mechanical properties of collagen meshes with different cross-linking percentages before and after Adipose Derived Stromal Cells (ADSC) seeding were studied as well as the cell-scaffold interaction. Uniaxial tensile tests of the collagen meshes with three different cross-linking percentages (full-, partial-, and noncross-linked) were carried out along orthogonal directions. Their mechanical properties were studied with the same tests before and after seeding with human derived adipose stem cells (ADSC) after 1 and 7 days. Histological analyses were performed to determine adhesion and proliferation of ADSC. Significant differences in mechanical properties of the unseeded meshes were observed between each orthogonal direction independently of the cross-linking percentage. A better cell adhesion rate was observed in the cross-linked meshes. An increase in the mechanical properties after cell seeding was observed with a direct relation with the degree of cross-linking. All meshes analyzed showed a marked anisotropy that should be taken into account during the surgical procedure. The cross-linking treatment increased cell adhesion and the mechanical properties of the collagen meshes after seeding. These results suggest that the mechanical properties of this type of collagen mesh could be useful as scaffolds for repair of pelvic organ prolapse.

Runx2 Overexpression in Bone Marrow Stromal Cells Accelerates Bone Formation in Critical-Sized Femoral Defects

The repair of large nonunions in long bones remains a significant clinical problem due to high failure rates and limited tissue availability for auto- and allografts. Many cell-based strategies for healing bone defects deliver bone marrow stromal cells (BMSCs) to the defect site to take advantage of the inherent osteogenic capacity of this cell type. However, many factors, including donor age and ex vivo expansion of the cells, cause BMSCs to lose their differentiation ability. To overcome these limitations, we have genetically engineered BMSCs to constitutively overexpress the osteoblast-specific transcription factor Runx2. In the present study, we examined Runx2-modified BMSCs, delivered via polycaprolactone scaffolds loaded with type I collagen meshes, in critical-sized segmental defects in rats compared to unmodified cells, cell-free scaffolds, and empty defects. Runx2 expression in BMSCs accelerated healing of critical-sized defects compared to unmodified BMSCs and defects receiving cell-free treatments. These findings provide an accelerated method for healing large bone defects, which may reduce recovery time and the need for external fixation of critical-sized defects.

Drainage of Collections Associated with Hernia Mesh: Is it Worthwhile?

Synthetic mesh has revolutionized abdominal wall hernia repair. However, mesh infections present a clinical problem because the standard practice of surgical excision is fraught with increased morbidity. Here, single-institutional outcomes in managing mesh-related collections via percutaneous drainage are retrospectively reviewed to assess its effectiveness. A total of 21 patients underwent drainage of perimesh collections. Three types of mesh were employed: polytetrafluoroethylene (PTFE; n = 5), polypropylene (n = 14), and porcine dermal collagen (n = 3). One patient received both polypropylene and PTFE. Drainage was performed with ultrasound guidance (n = 19) or surgical drain exchange (n = 2). Mesh type, culture results, fluid collection size, and location were analyzed with respect to need for mesh excision. Sixteen of 21 patients (76%) were successfully treated with drainage. One required additional surgical capsulectomy; the mesh was salvaged. Four required mesh excision because of recurrent infection (n = 2) or lack of improvement of clinical course (n = 2). Recurrent infection occurred in six patients, with mesh salvage via conservative management or new drainage in four. Fluid cultures were positive in 68% of patients (n = 13), with Staphylococcus aureus the most common organism. Cultures did not predict mesh excision (P = .26). The PTFE excision rate trended higher compared with polypropylene (40% vs 14%; P = .27). No porcine dermal collagen mesh was excised. Neither fluid collection size nor location predicted mesh excision. Mean follow-up was 319 days (range, 6-1,406 d). Percutaneous drainage of suspected mesh-related abscess is effective. The use of PTFE mesh trended toward a higher excision rate.

Incisional hernia in action: the use of vacuum-assisted closure and porcine dermal collagen implant

In this paper, we describe our experience in the successful use of vacuum-assisted closure (VAC) and porcine dermal collagen (PDC) mesh reconstruction of a complicated contaminated abdominal wall defect resulting from a strangulated incisional hernia with late jejunal perforation in a 57-year-old obese and diabetic woman.

Hemostatic Step‐by‐Step Procedure to Control Presacral Bleeding After Laparoscopic TME

Laparoscopic total mesorectal excision (TME) is a complex procedure being performed with increasing frequency in the surgical community. Indeed, a number of authors have described excellent short-term and oncological outcomes with a laparoscopic approach to rectal cancer. Presacral bleeding is a rare but well-recognized complication after open TME. Various management strategies have been described, many of which have been discussed by the authors of this article [1]. In this case series, the authors describe a sensible and simple algorithm for the management of presacral bleeding. Initial use of bipolar cautery or suturing is followed by cautery through an absorbable fabric mesh, then cautery through a taenia epiploica or piece of omentum, and finally use of a piece of bovine pericardium with a laparoscopic tacking instrument. These are all sensible recommendations. Nevertheless, the key remains to avoid this complication as much as possible, meaning that training of surgeons in identification of the anatomical planes is of primary importance for avoiding bleeding problems. A potential addition to the algorithm should be the site of bleeding. While a tacker works well on the sacrum, it obviously is not suitable for bleeding from the lateral pelvic sidewall, or anteriorly. Resolving bleeding at these sites requires precise suturing or cautery—techniques that may not work as well for true presacral bleeding, especially if the presacral fascia has been completely removed. Another option is to use a tacking instrument with the collagen mesh in the presacral area, saving the requirement for bovine pericardium. This is a useful article that reminds surgeons of exit strategies that can be used during difficult laparoscopic operations. This algorithm may even be useful in open surgery, as trying to get a thumb-tack to stay on the sacrum can be difficult, whereas a laparoscopic coiled tack should work well.

Abstract No. 98: Drainage of Collections Associated with Hernia Mesh: Is It Worthwhile?

The introduction of synthetic mesh has revolutionized abdominal wall hernia repair. However, mesh infections present a major clinical problem since the standard practice of surgical excision is fraught with increased morbidity. We present our experience managing mesh-related fluid collections via percutaneous drainage. 21 patients underwent percutaneous drainage of peri-mesh fluid collections between September 2002 and September 2008. Medical records were reviewed retrospectively with IRB approval. Three types of mesh were employed, including polytetrafluoroethylene (PTFE, n=5), polypropylene (n=14), and porcine dermal collagen (n=3). Median time from hernia surgery to first IR drainage was 47 days. Initial percutaneous drainage was performed using ultrasound guidance (n=19) or via exchange of a surgical drain (n=2). Mean follow-up was 319 days (range 6 to 1406 days). Overall, 16 of 21 patients (76%) with a peri-mesh fluid collection were successfully managed via antibiotics and percutaneous drainage. One patient required additional surgical capsulectomy; the mesh was salvaged. The remaining 4 patients required mesh excision because of recurrent infections (n=2) or non-improving clinical course (n=2). Recurrent infection occurred in 6 patients, with mesh salvage via conservative management or new percutaneous drainage in 4 of these. The cultures of the fluid collection were positive in 68% of patients (13/19 patients), with Staphylococcus aureus as the most common organism. While all patients with negative cultures were treated successfully via drainage, the culture results were not a significant predictor for mesh excision (p=0.26). The excision rate for PTFE mesh was higher than that for polypropylene mesh, but not statistically significant (40% vs. 14%, p=0.27). No porcine dermal collagen mesh was excised. Neither the size of the fluid collection nor the location (within fascia or subcutaneous tissue) was predictive of mesh excision. Conservative management with percutaneous drainage of suspected mesh-related abscess is an effective strategy. PTFE mesh trended toward a higher excision rate; a larger study might help confirm this trend.

Novel 3D biomaterials for tissue engineering based on collagen and macroporous ceramics

AbstractIn this study, different collagen and ceramic based materials were characterized concerning their mechanical and biocompatible properties. Therefore, they were tested in static and dynamic cultivation using human mesenchymal stem cells derived from adipose tissue. Zirconia based macroporous ceramic materials with different BET surface areas (Sponceram® 30/90, Sponceram® 30/145) and surface coatings (Hydroxyapatit, Titandioxide: Sponceram®/HA, Sponceram®/Ti) were mechanically evaluated regarding their maximal tension, maximal deformation and their permeability. The maximal tension and maximal deformation of the different ceramic materials were comparable though the permeability of the uncoated ceramic with the largest BET surface area (Sponceram® 30/90) was significantly increased compared to the other ceramics. A porous collagen matrix (Matristypt®) and a porous collagen‐elastin‐matrix (Matriderm®) were similarly evaluated concerning their maximal tension and maximal deformation and compared with decellularized skin. The maximal deformations of the porous collagen materials were comparable but significantly increased compared to decellularized skin. The maximal tension of the porous matrices was five times lower than the maximal tension of decellularized skin. For the evaluation for cell culture applications, Sponceram®, Sponceram®/HA and two collagen meshes (Matristypt®, Matriderm®) were seeded with human mesenchymal stem cells. Sponceram® was compared to β‐Tricalciumphosphate. The scaffolds were cultivated under static conditions over a time period of 14 days or 21 days respectively. The cell proliferation was examined in regular intervals using MTT assay. The cells growing on the collagen‐elastin matrix showed increased proliferation in comparison to the cells grown on the pure collagen matrix. The ceramic materials tested statically in cell culture (Sponceram®, Sponceram®/HA) did not show different influence on the proliferation of seeded cells but it was increased compared to the proliferation of the cells seeded on β‐Tricalciumphosophate. In a rotating bed bioreactor system (Z®RP system, Zellwerk GmbH) the human mesenchymal stem cells were cultured under dynamic conditions on Sponceram® over a time period of 47 days using osteogenic differentiation medium. Continuous increasing glucose consumption and lactate production gives evidence of good cell proliferation. After cultivation, the Sponceram® discs were stained with von kossa and alizarin red which showed matrix calcification. In summary, the tested collagen‐ and ceramic materials are applicable for the cell culture applications whereas the ceramic materials are presenting a promising approach for bone tissue engineering implementations.

Reinforced bioartificial dermis constructed with collagen threads

In this work, a novel type of composite scaffold was designed, which has the suitability of both high biocompatibility and strong mechanical properties, for use in bioartificial dermis applications. The reinforced scaffold consisted of a lyophilized collagen sponge formed around a cross-linked collagen meshwork with an average thread diameter of approximately 55 μm. Fibroblasts were cultured in the reinforced collagen sponge for 7 days, during which time the pores in the sponge became filled with cells that secreted extracellular matrix (ECM) to form a bioartificial dermis. Results of ultimate tensile strength (UTS) measurements and compression tests indicated that the bioartificial dermis formed around the reinforced collagen sponge showed about ten times the strength of the bioartificial dermis formed around a typical collagen sponge (1.5 ± 0.05 vs. 0.15 ± 0.05 and 2.5 ± 0.1 vs. 0.2 ± 0.08 MPa, respectively). As a result, reinforced collagen mesh improved mechanical properties and this technique will be possible to make stronger scaffolds, not only for artificial skin applications but also various artificial tissues, such as synthetic cartilage, bone, and blood vessels.

Determinants of Bioartificial Myocardial Graft Survival and Engraftment In Vivo

The specific interactions between tissue-engineered grafts and host tissue are frequently neglected. The aim of this study was to describe and quantify the fate of a tissue-engineered cardiac graft in vivo. Neonatal rat cardiomyocytes were cast into a collagen mesh, forming a bioartificial myocardial tissue (AMT). After 7 days in vitro, four groups were formed (Group A: sham; Group B: matrix; Group C: AMT [with additional host treatment with cyclosporine and prednisolone]; Group D: AMT; each n = 5) and the tissue grafts were implanted into the muscle pouch of adult rats at 14, 21 and 28 days. Implants were stained for troponin-T, BrdU, MF-20, desmin, vimentin, Flk-1, CD8, CD4, pentachrome, PSR and H&E. AMT cell count, cell proportion, contractility, viability and metabolism proved stable in vitro. Grafted cells decreased over time and were detected in Group C until the end of the experiment (Day 28), and in Group D until Day 21. Angiogenesis began at the peripheries and slowly progressed toward the cores of the grafts. The thickness and collagen content of the matrix remained stable in Group C for 14 days, and decreased in all groups until Day 28 (thickness: Group B, -66%; Group C, -50%; Group D, -100%). Grafts were predominately infiltrated by macrophages and stromal cells, and less so by lymphocytes (Group D > B > C). The differentiation of cardiac and non-cardiac grafted cells, infiltrating cells, scaffold kinetics and angiogenesis showed host immune responses and degree of angiogenesis to be the determinants for AMT graft survival.