Stromal vascular fraction cells as biologic coating of mesh for hernia repair

11 p.Background. The interest in non-manipulated cells originating from adipose tissue has raised tremendously in the field of tissue engineering and regenerative medicine. The resulting stromal vascular fraction (SVF) cells have been successfully used in numerous clinical applications. The aim of this experimental work is, first to combine a macroporous synthetic mesh with SVF isolated using a mechanical disruption process, and to assess the effect of those cells on the early healing phase of hernia. Methods. Human SVF cells combined with fibrin were used to coat commercial titanized polypropylene meshes. In vitro, viability and growth of the SVF cells were assessed using live/dead staining and scanning electron microscopy. The influence of SVF cells on abdominal wall hernia healing was conducted on immunodeficient rats, with a focus on short-term vascularization and fibrogenesis. Results. Macroporous meshes were easily coated with SVF using a fibrin gel as temporary carrier. The in vitro experiments showed that the whole process including the isolation of human SVF cells and their coating on PP meshes did not impact on the SVF cells? viability and on their capacity to attach and to proliferate. In vivo, the SVF cells were well tolerated by the animals, and coating mesh with SVF resulted in a decrease degree of vascularity compared to control group at day 21. Conclusions. The utilization of SVF-coated mesh influences the level of angiogenesis during the early onset of tissue healing. Further long-term animal experiments are needed to confirm that this effect correlates with a more robust mesh integration compared to non-SVF-coated mesh.European Hernia Society Research GrantTU

An Efficacy Comparison of Two Hemostatic Agents in a Porcine Liver Bleeding Model: Gelatin/Thrombin Flowable Matrix versus Collagen/Thrombin Powder

Purpose: Management of bleeding during surgery can be aided by the application of topical hemostatic agents. This study compared the hemostatic efficacy of a new powder agent containing collagen, chondroitin sulfate, and thrombin (PCCT) with a flowable gelatin-thrombin matrix with smooth particles (SmGM) in a porcine liver bleeding model. Materials and Methods: Lesions 4–6 mm deep and ∼10 mm in diameter were created in porcine livers and treated with either SmGM or PCCT. Bleeding rate and grade were quantified before and 3, 7, and 11 minutes after treatment. Results: Thirty-two lesions each were treated with SmGM or PCCT; the median (Q1, Q3) initial bleeding rate was comparable between the two groups (8.43 [6.18, 10.68] g/min and 7.15 [5.16, 9.63] g/min, respectively). The residual bleeding rate was significantly lower at all time-points post treatment for SmGM compared with PCCT (3 minutes: 0.14 [0.07, 0.21] versus 0.46 [0.20, 1.20] g/min, p < 0.0001; 7 minutes: 0.07 [0.04, 0.11] versus 0.12 [0.08, 0.39] g/min, p = 0.001; 11 minutes: 0.05 [0.03, 0.08] versus 0.07 [0.05, 0.12] g/min, p = 0.043). Bleeding grade at 3 minutes was also significantly lower for SmGM compared with PCCT (median [Q1, Q3] 0.0 [0.0, 0.0] versus 1.0 [1.0, 2.0], p < 0.0001). PCCT required reapplication in approximately one-third of applications due to insufficient hemostasis 4 minutes after initial application and showed a tendency to stick to the wet gauze during approximation. Conclusions: In this bleeding model, treatment with SmGM resulted in reduced blood loss, no need for reapplication and was easier to apply compared with PCCT

A Comparative Efficacy Evaluation of Recombinant Topical Thrombin (RECOTHROM®) With A Gelatin Sponge Carrier Versus Topical Oxidized Regenerated Cellulose (TABOTAMP®/SURGICEL®) In A Porcine Liver Bleeding Model

Purpose Topical hemostatic agents can be classified as active or passive. This study compared the hemostatic efficacy of an active agent, recombinant thrombin (RECOTHROM® [rT]) plus gelatin sponge carrier versus a passive agent, oxidized regenerated cellulose (TABOTAMP®/SURGICEL® [ORC]), in a porcine liver abrasion model. Materials and Methods Eight pigs were used, four of them were heparinized. A total of 80 liver lesions were created, 40 of them in heparinized pigs. Lesions were treated with rT plus gelatin sponge or ORC. Bleeding rate was quantified before treatment by applying pre-weighed gauze. Time to hemostasis was assessed visually for 10 minutes. Results Seven of the 80 lesions were excluded for having initial bleeding rates exceeding the target of 10 g/min. Sixteen and 20 lesions were treated with rT plus gelatin sponge and 19 and 18 lesions were treated with ORC, in non-heparinized and heparinized animals, respectively. Time to hemostasis (median [IQR]) was significantly shorter with rT plus gelatin sponge (30 [30,30] seconds) in heparinized and non-heparinized animals versus ORC in non-heparinized (180 [120,210] seconds) and heparinized animals (215 [135,345] seconds); P 5–10 g/min (285 [225,394] seconds) versus ≤5 g/min (175 [108,290] seconds). Conclusions In this model, rT plus gelatin sponge carrier (active) was a more effective hemostat than ORC (passive) in both heparinized and non-heparinized animals

Efficacy of Topical Hemostatic Agents: A Comparative Evaluation of Two Gelatin/Thrombin-Based Hemostatic Matrices in a Porcine Kidney Surgical Model

Purpose: Topical hemostatic agents are an important means of controlling or preventing bleeding. This study was performed to compare gelatin–thrombin matrix with smooth particles (SmGM) versus gelatin–thrombin matrix with stellate particles (StGM) in a porcine kidney bleeding model. Materials and methods: In male pigs, reproducible lesions (diameter and depth ∼10 mm) were created in the renal cortex. Each lesion was treated topically using either SmGM or StGM. Blood loss was quantified before and 2, 5 and 10 minutes after treatment. Dry mass, ultrastructural and histologic analyses were also performed. Results: Thirty-two lesions were treated with SmGM and 32 with StGM; median initial bleeding rates were 27.6 and 29.1 mL/min, respectively. Two minutes post-application, SmGM was associated with significantly less bleeding than StGM (0.574 vs 0.920 mL/min; p 29 mL/min, where bleeding rates at 2 minutes were ∼3-fold higher with StGM (1.636 vs 0.567 mL/min; p ≥ 0.040). Dry mass per unit volume of hemostatic agent was significantly higher with SmGM versus StGM. SmGM formed discrete, smooth particles, while StGM particles were stellate and tended to coalesce. Histologic analysis showed more solid mass, larger particles and less intervening space with SmGM versus StGM. Conclusions: In a severe, high-volume bleeding model, residual bleeding at 2 minutes was significantly lower with SmGM versus StGM, and SmGM showed greater consistency across bleeding intensities. These findings may be attributable to dry mass per unit volume and/or ultrastructural differences between the two agents

Human adipose derived stem cells reduce callus volume upon BMP-2 administration in bone regeneration

INTRODUCTION: The demand for new therapeutic approaches to treat bone defects and fractures is increasing in trauma surgery and orthopaedics because the number of patients with degenerative diseases is continuously growing. "Tissue Engineering" offers promising new technologies that combine the three components - cells, growth factors and matrix. Efforts are targeted at improving and accelerating recovery, especially for long bone fractures, and reducing the risk of delayed bone healing or pseudoarthrosis. Adult human adipose-derived stem cells (ASC) can differentiate into osteoblasts in an osteogenic surrounding. Bone morphogenetic protein-2 (BMP-2) accelerates and initiates this differentiation. Fibrin, a matrix that promotes wound healing, is a promising carrier for ASCs and BMP-2.MATERIALS AND METHODS: In this study, a 2mm transcortical drill hole in the femur of male rats served as a small non-critical size defect model for fracture simulation. In vivo bone healing was investigated upon administration of the growth factor BMP-2 embedded with ASCs in a locally applied fibrin matrix. Groups with the components alone were also investigated. After 2 and 4 weeks, μCT and histology were performed to determine the bone and callus volume.RESULTS AND DISCUSSION: After only a short period of time (2 and 4 weeks), this animal model discloses comparative information about the osteogenetic potential and bone regeneration with little effort (no osteosynthesis necessary). The most significant result found in this model is that the combination of ASCs and BMP-2 in a fibrin matrix significantly reduces callus formation after 2 weeks compared to BMP-2 alone. BMP-2 alone significantly increased callus formation. ASCs embedded alone in the fibrin matrix did not lead to increased bone regeneration.CONCLUSION: Transplantation of ASC modulated the callus induction by BMP-2 to a normal volume.</p

Alveolar bone regeneration in response to local application of calcitriol in vitamin D deficient rats

AIM Vitamin D deficiency is considered to diminish bone regeneration. Yet, raising the serum levels takes months. A topic application of the active vitamin D metabolite, calcitriol, may be an effective approach. Thus, it becomes important to know the effect of vitamin D deficiency and local application on alveolar bone regeneration. MATERIAL AND METHODS Sixty rats were divided into three groups; two vitamin depletion groups and a control group. Identical single defects (2 mm diameter) were created in the maxilla and mandible treated with calcitriol soaked collagen in one deficiency group while in the other two groups not. Histomorphometric analysis and micro CTs were performed after 1 and 3 weeks. Serum levels of 25(OH)D3 and PTH were determined. RESULTS Bone formation rate significantly increased within the observation period in all groups. Bone regeneration was higher in the maxilla than in the mandible. However, bone regeneration was lower in the control group compared to vitamin depletion groups, with no significant effects by local administration of calcitriol (micro CT mandible p = 0.003, maxilla p < 0.001; histomorphometry maxilla p = 0.035, mandible p = 0.18). CONCLUSION Vitamin D deficiency not necessarily impairs bone regeneration in the rat jaw and a single local calcitriol application does not enhance healing

Induced Hypothermia Does Not Harm Hemodynamics after Polytrauma:A Porcine Model

Background. The deterioration of hemodynamics instantly endangers the patients’ life after polytrauma. As accidental hypothermia frequently occurs in polytrauma, therapeutic hypothermia still displays an ambivalent role as the impact on the cardiopulmonary function is not yet fully understood. Methods. We have previously established a porcine polytrauma model including blunt chest trauma, penetrating abdominal trauma, and hemorrhagic shock. Therapeutic hypothermia (34°C) was induced for 3 hours. We documented cardiovascular parameters and basic respiratory parameters. Pigs were euthanized after 15.5 hours. Results. Our polytrauma porcine model displayed sufficient trauma impact. Resuscitation showed adequate restoration of hemodynamics. Induced hypothermia had neither harmful nor major positive effects on the animals’ hemodynamics. Though heart rate significantly decreased and mixed venous oxygen saturation significantly increased during therapeutic hypothermia. Mean arterial blood pressure, central venous pressure, pulmonary arterial pressure, and wedge pressure showed no significant differences comparing normothermic trauma and hypothermic trauma pigs during hypothermia. Conclusions. Induced hypothermia after polytrauma is feasible. No major harmful effects on hemodynamics were observed. Therapeutic hypothermia revealed hints for tissue protective impact. But the chosen length for therapeutic hypothermia was too short. Nevertheless, therapeutic hypothermia might be a useful tool for intensive care after polytrauma. Future studies should extend therapeutic hypothermia