Fibrin glue reduces the severity of intra-abdominal adhesions in a rat model

Biocompatible Nanocomposites for Postoperative Adhesion: A State-of-the-Art Review

To reduce and prevent postsurgical adhesions, a variety of scientific approaches have been suggested and applied. This includes the use of advanced therapies like tissue-engineered (TE) biomaterials and scaffolds. Currently, biocompatible antiadhesive constructs play a pivotal role in managing postoperative adhesions and several biopolymer-based products, namely hyaluronic acid (HA) and polyethylene glycol (PEG), are available on the market in different forms (e.g., sprays, hydrogels). TE polymeric constructs are usually associated with critical limitations like poor biocompatibility and mechanical properties. Hence, biocompatible nanocomposites have emerged as an advanced therapy for postoperative adhesion treatment, with hydrogels and electrospun nanofibers among the most utilized antiadhesive nanocomposites for in vitro and in vivo experiments. Recent studies have revealed that nanocomposites can be engineered to generate smart three-dimensional (3D) scaffolds that can respond to different stimuli, such as pH changes. Additionally, nanocomposites can act as multifunctional materials for the prevention of adhesions and bacterial infections, as well as tissue healing acceleration. Still, more research is needed to reveal the clinical potential of nanocomposite constructs and the possible success of nanocomposite-based products in the biomedical market.

The Therapeutic Potential of Targeting Key Signaling Pathways as a Novel Approach to Ameliorating Post-Surgical Adhesions

BACKGROUND

Peritoneal adhesions (PA) are a common complication of abdominal operations. A growing body of evidence shows that inhibition of inflammation and fibrosis at sites of peritoneal damaging could prevent the development of intra-abdominal adhesions.

METHODS

A search of PubMed, Medline, CINAHL and Embase databases was performed using the keywords 'postsurgical adhesion', 'post-operative adhesion', 'peritoneal adhesion', 'surgery-induced adhesion' and 'abdominal adhesion'. Studies detailing the use of pharmacological and non-pharmacological agents for peritoneal adhesion prevention were identified, and their bibliographies were thoroughly reviewed to identify further related articles.

RESULTS

Several signaling pathways, such as tumor necrosis factor-alpha, tissue plasminogen activator, and type 1 plasminogen activator inhibitor, macrophages, fibroblasts, and mesothelial cells play a key part in the development of plasminogen activator. Several therapeutic approaches based on anti-PA drug barriers and traditional herbal medicines have been developed to prevent and treat adhesion formation. In recent years, the most promising method to prevent PA is treatment using biomaterial-based barriers.

CONCLUSION

In this review, we provide an overview of the pathophysiology of adhesion formation and various agents targeting different pathways, including chemical agents, herbal agents, physical barriers, and clinical trials concerning this matter.

Peritoneal adhesions: Occurrence, prevention and experimental models

Peritoneal adhesions (PA) are a postoperative syndrome with high incidence rate, which can cause chronic abdominal pain, intestinal obstruction, and female infertility. Previous studies have identified that PA are caused by a disordered feedback of blood coagulation, inflammation, and fibrinolysis. Monocytes, macrophages, fibroblasts, and mesothelial cells are involved in this process, and secreted signaling molecules, such as tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10), tissue plasminogen activator (tPA), and type 1 plasminogen activator inhibitor (PAI-1), play a key role in PA development. There have been many attempts to prevent PA formation by anti-PA drugs, barriers, and other therapeutic methods, but their effectiveness has not been widely accepted. Treatment by biomaterial-based barriers is believed to be the most promising method to prevent PA formation in recent years. In this review, the pathogenesis, treatment approaches, and animal models of PA are summarized and discussed to understand the challenges faced in the biomaterial-based anti-PA treatments.

Applications of Fibrin Sealant in Surgery

Fibrin sealant has been used with increasing frequency in a variety of surgical field for its unique hemostatic and adhesive abilities. Fibrin sealant mimics the last step of the coagulation cascade and takes place independently of the patient's coagulation status. With rapid advances in minimally invasive surgery, the potential uses for this type of biologic and synthetic material are expanding exponentially. This article reviews the data associated with the application of fibrin sealant in various surgical procedures. From reinforcing gastrointestinal anastomosis to repair perforated duodenal ulcers to mesh fixation in laparoscopic inguinal hernia repair, fibrin sealant is gaining increasing acceptance among surgeons. The applications of fibrin sealant are expanding, and new preparations of fibrin sealant are currently being evaluated.

Prevention of Polyglycolic Acid-Induced Peritoneal Adhesions Using Alginate in a Rat Model

Postoperative intra-abdominal or intrathoracic adhesions sometimes cause significant morbidity. We have designed three types of alginate-based treatments using strongly cross-linked (SL), weakly cross-linked (WL), and non-cross-linked (NL) alginate with calcium gluconate. In rat experiments, we compared the antiadhesive effects of the three types of alginate-based treatments, fibrin glue treatment (a standard treatment), and no treatment against adhesions caused by polyglycolic acid (PGA) mesh (PGA-induced adhesions). The antiadhesive materials were set on the PGA sheet fixed on the parietal peritoneum of the abdomen. Fifty-six days later, the adhesions were evaluated macroscopically by the adhesion scores and microscopically by hematoxylin-eosin staining and immunostaining. We also tested the fibroblast growth on the surface of the antiadhesive materials in vitro. The antiadhesive effects of WL and NL were superior to the no treatment and fibrin glue treatment. A microscopic evaluation confirmed that the PGA sheet was covered by a peritoneal layer constructed of well-differentiated mesothelial cells, and the inflammation was most improved in the NL and WL. The fibroblast growth was inhibited most on the surfaces of the NL and WL. These results suggest that either the WL or NL treatments are suitable for preventing PGA-induced adhesions compared to SL or the conventional treatment.

Analysis of adhesions resulted from mesh fixation with fibrin sealant and suture: experimental intraperitoneal model

OBJECTIVE

To compare surgical fixation of polypropylene mesh (PP) and coated polypropylene mesh (PCD) using polypropylene suture and fibrin glue, as for the formation of intraperitoneal adhesions.

METHODS

A sample of 46 female Wistar rats were randomized into six groups: two control groups, with five rats each, were subjected to one medial incision (MI) and the other to a U-shaped incision (UI), none of these groups received the mesh. Two groups of PP mesh, with ten rats, fixed with suture (PPF), the other with six rats, fixed with biological glue (PPC). And two groups of PCD mesh, at first, with ten animals, the mesh was fixed with sutures (PCDFs) and the second with ten animals with biological glue (PCDC).

RESULTS

After 21 days, the control groups showed no significant adhesions. The PPC group showed a lower degree of adhesion than the PPF group (p = 0.01). There was no difference between the groups with PCD.

CONCLUSION

Comparison of fixation was statistically different only with PP mesh, with lesser degrees of adherence when using the glue. Adhesions were predominantly located at the extremities of the meshes studied.

Effectiveness of the combined use of lactic acid film and polypropylene mesh in the formation of intraperitoneal adhesions--an experimental model in rats

OBJECTIVE

To evaluate the efficacy of a lactic acid biomaterial (SurgiWrap®) as a protector of the polypropylene mesh (Marlex®) regarding the formation of intraperitoneal adhesions in rats.

METHODS

Forty Wistar rats formed the following groups: Group 0 (Sham)--only laparotomy; Group I--polypropylene mesh; Group II--polypropylene mesh protected by a film of lactic acid. These animals were submitted to laparotomy and placement (or not) of the meshes at closing. After 21 days they were sacrificed for analysis of the adhesion type (0-3), percentage of affected area and strength needed to rupture.

RESULTS

Group 0 showed no intraperitoneal adhesions. Regarding classification, type 3 adhesions had the highest prevalence in both groups 1 and 2. As for the strength to break adhesions, Group 1 had an average of 1.58 N and Group 2, 1.23 N. The mesh was surrounded by adhesions in more than 50% of their surface area in 87% of Group 1 subjects and in 84% of Group 2 individuals. Through different statistical methods we found that there was no significant difference between groups for both variables.

CONCLUSION

The combined use of polypropylene mesh and lactic acid bioprotector showed similar results in relation to intraperitoneal adhesion formation when compared to the sole use of the same mesh.

Systematic review of the use of fibrin sealant in abdominal-wall repair surgery

PURPOSE

Our objective was to analyze the advantages and inconveniences associated with the use of fibrin sealant compared with mechanical means for mesh fixation following abdominal-wall surgery.

METHODS

Literature search was conducted in MedLine, EMBASE, and Cochrane Library Plus databases. Articles were randomized clinical trials, nonrandomized comparative studies, and case series containing at least ten patients.

RESULTS

The fibrin sealant was shown to be biocompatible with the surrounding tissue. In patients treated with fibrin sealant, lower prevalence of acute and chronic postoperative pain was observed, and less hemorrhagic complications occurred. There are no data on the influence of fibrin sealant on seroma decrease. Efficiency in experimental models was similar to that observed for mechanical methods of fixation. Also, adhesions with fibrin sealant were less than that for mechanical methods.

CONCLUSIONS

Compared with mechanical methods, fibrin sealant is an efficacious alternative for mesh fixation postsurgery of the abdominal wall.

A prospective, randomised, controlled, double-blind phase I-II clinical trial on the safety of A-Part Gel as adhesion prophylaxis after major abdominal surgery versus non-treated group

Background

Postoperative adhesions occur when fibrous strands of internal scar tissue bind anatomical structures to one another. The most common cause of intra-abdominal adhesions is previous intra-abdominal surgical intervention. Up to 74% of intestinal obstructions are caused by post surgical adhesions. Although a variety of methods and agents have been investigated to prevent post surgical adhesions, the problem of peritoneal adhesions remains largely unsolved. Materials serving as an adhesion barrier are much needed.

Methods/Design

This is a prospective, randomised, controlled, patient blinded and observer blinded, single centre phase I-II trial, which evaluates the safety of A-Part^® Gel as an adhesion prophylaxis after major abdominal wall surgery, in comparison to an untreated control group. 60 patients undergoing an elective median laparotomy without prior abdominal surgery are randomly allocated into two groups of a 1:1- ratio. Safety parameter and primary endpoint of the study is the occurrence of wound healing impairment or peritonitis within 28 (+10) days after surgery. The frequency of anastomotic leakage within 28 days after operation, occurrence of adverse and serious adverse events during hospital stay up to 3 months and the rate of adhesions along the scar within 3 months are defined as secondary endpoints. After hospital discharge the investigator will examine the enrolled patients at 28 (+10) days and 3 months (±14 days) after surgery.

Discussion

This trial aims to assess, whether the intra-peritoneal application of A-Part^® Gel is safe and efficacious in the prevention of post-surgical adhesions after median laparotomy, in comparison to untreated controls.

Trial registration

NCT00646412

Granulation tissue formation at the bronchial stump is reduced after stapler closure in comparison to suture closure in dogs

The aim of this study was to compare the morphology of the bronchial stump after lobectomy between mechanical stapler closure and manual suture closure. The effect of fibrin glue application on each method of closure was also observed. Right upper lobectomy was performed in beagles (n=31) using staplers (ST group) or sutures (SU group). In a separate experiment, fibrin glue was sprayed onto the stump after each respective method of closure. After one week, the stump region was examined macroscopically, and also by histology. chi(2)-Test and Mann-Whitney test were used for comparative analysis. The incidence of adhesion formation between the surrounding tissues was significantly reduced in the ST group in comparison to the SU group (22 vs. 80%, P=0.04). The thickness of granulation tissue over the stump was significantly reduced in the ST group in comparison to the SU group (0.8+/-0.2 vs. 2.5+/-0.3 mm, P<0.0001). Vessel density in the granulation tissue was also significantly reduced in the ST group in comparison to the SU group (6+/-2 vs. 16+/-2, P=0.003). Fibrin glue application after stapler closure significantly increased the incidence of adhesion formation, granulation tissue thickness, and vessel density in the granulation tissue over the stump.

Fixation of mesh to the peritoneum using a fibrin glue: investigations with a biomechanical model and an experimental laparoscopic porcine model

BACKGROUND

In recent years, the use of fibrin glue has become an established practice in several areas of surgical treatment. For example, fibrin glue is used increasingly as an alternative method for mesh fixation in hernia surgery, significantly helping to reduce the incidence of chronic pain. The experiments in this study were aimed at elucidating the extent to which tack- or suture-based permanent fixation can be replaced by fixation with fibrin glue for laparoscopic intraperitoneal repair of abdominal wall hernias.

METHODS

In an initial series of experiments conducted with a biomechanical model, the strength of the fibrin glue for fixation of lightweight mesh (TiMesh light) to muscle tissue was compared with its strength of fixation to the peritoneum. In a second series of experiments, mesh was laparoscopically implanted in an established porcine model. Fibrin glue was used for mesh fixation in six animals. Laparoscopic exploration and explantation of the meshes were conducted after 4 months. Planimetric analysis was performed to investigate adhesion and shrinkage of the mesh surface.

RESULTS

The strength of fibrin glue for fixation of mesh to the peritoneum was significantly less than for its fixation to muscle tissue (11.86 N vs. 47.88 N; p = 0.001). Three of the implanted meshes were not completely integrated, and two of these were dislocated. On the average, adhesions were seen on 16% of the mesh surfaces. The mesh shrinkage rate was 24.2%.

CONCLUSION

Mesh fixation alone to the undamaged peritoneum in the intraperitoneal region cannot be recommended because of the risk for dislocation. Additional fixation using sutures, tacks, or both is needed until the mesh material is completely integrated.

The comparison of diphenhydramine HCl and Nedocromil sodium in prevention of abdominal postoperative adhesion formation in rat models: An experimental study

BACKGROUND

The purpose of this study was to determine the effects of diphenhydramine HCl and Nedocromil sodium for the prevention of postsurgical adhesion formation in rat model.

METHODS

Sixty adult female rats were anesthetized by 5mg/kg ketamine hydrochloride. After opening the abdominal wall, a 2 cm(2) peritoneal layer was excised from the left abdominal wall and 10 longitudinal incisions of 2 to 3 cm in length were made on the right parietal peritoneum. The abdominal wall was closed with 4/0 atraumatic continuous nylon sutures. Group I was the control group, group II was given 10mg/kg diphenhydramine HCl, group III was given 100mg/kg Nedocromil sodium, and group IV was administered both drugs in the above doses. All the drugs were instilled into the peritoneal cavity after abdominal closure except Nedocromil sodium which was administered in two separate doses 30 min before surgery and just after abdominal closure. Relaparatomy was performed 2 weeks after the initial surgery and abdominal adhesions were scored. Kruskal-Wallis and Mann-Whitney U-test were used for the statistical evaluation.

RESULTS

The mean+/-S.D. (median) of adhesion scores were 2.5+/-0.90 (2.0), 1.58+/-0.99 (1.0), 0.92+/-0.86 (1.0) and 1.75+/-0.75 (2.0) in group I, II, III and IV, respectively. There were significant differences between the scores of groups I and II (P=0.033), groups I and III (P<0.001), and groups I and IV (P=0.033).

CONCLUSION

Both diphenhydramine HCl and Nedocromil sodium reduced postoperative abdominal adhesions separately and in combination with each other in our study. Average score of adhesion formation was lowest in the group that was administered Nedocromil sodium. More research is needed in order to discover any positive effect of these drugs as antiadhesive agents in humans.

Autologous platelet gel and fibrin sealant enhance the efficacy of total knee arthroplasty: improved range of motion, decreased length of stay and a reduced incidence of arthrofibrosis

In this study we describe the potential role of autologous platelet gel and fibrin sealant in unilateral total knee arthroplasty to improve the postoperative range of motion and to reduce the incidence of arthrofibrosis. Total knee arthroplasty is often associated with a considerable amount of post-operative blood loss. Persistent limited motion directly after surgery may ultimately result in arthrofibrosis. To counteract these effects we investigated whether the use of autologous derived platelet gel and fibrin sealant would reduce postoperative blood loss, decrease the impaired range of motion and the incidence of arthrofibrosis. All patients were consecutively operated and assigned to the study or control groups. Study group patients (n = 85) were treated with the application of autologous platelet gel and fibrin sealant at the end of surgery. Eighty patients were operated without the use of platelet gel and fibrin sealant, and served as the control group. The postoperative hemoglobin decrease, range of motion and length of hospitalization were recorded. During a 5-month postoperative period patients were followed to observe the incidence of arthrofibrosis. In patients in the treatment group the hemoglobin concentration in blood decreased significantly less when compared to the control group. They also showed a superior postoperative range of motion when compared to those of the control group (P < 0.001). The incidence of arthrofibrosis and subsequent forced manipulation was significantly less (P < 0.001) in patients managed with platelet gel and fibrin sealant. We conclude that peri-operatively applied platelet gel and fibrin sealant may improve the range of motion after total knee arthroplasty, decreases the length of stay and may reduce the incidence of arthrofibrosis.

Laparoscopic sleeve gastrectomy as an initial weight-loss procedure for high-risk patients with morbid obesity

BACKGROUND

The surgical treatment of obesity in the high-risk, high-body-mass-index (BMI) (>60) patient remains a challenge. Major morbidity and mortality in these patients can approach 38% and 6%, respectively. In an effort to achieve more favorable outcomes, we have employed a two-stage approach to such high-risk patients. This study evaluates our initial outcomes with this technique.

METHODS

In this study, patients underwent laparoscopic sleeve gastrectomy (LSG) as a first stage during the period January 2002-February 2004. After achieving significant weight loss and reduction in co-morbidities, these patients then proceeded with the second stage, laparoscopic Roux-en-Y gastric bypass (LRYGBP).

RESULTS

During this time, 126 patients underwent LSG (53% female). The mean age was 49.5 +/- 0.9 years, and the mean BMI was 65.3 +/- 0.8 (range 45-91). Operative risk assessment determined that 42% were American Society of Anesthesiologists physical status score (ASA) III and 52% were ASA IV. The mean number of co-morbid conditions per patient was 9.3 +/- 0.3 with a median of 10 (range 3-17). There was one distant mortality and the incidence of major complications was 13%. Mean excess weight after LSG at 1 year was 46%. Thirty-six patients with a mean BMI of 49.1 +/- 1.3 (excess weight loss, EWL, 38%) had the second-stage LRYGBP. The mean number of co-morbidities in this group was 6.4 +/- 0.1 (reduced from 9). The ASA class of the majority of patients had been downstaged at the time of LRYGB. The mean time interval between the first and second stages was 12.6 +/- 0.8 months. The mean and median hospital stays were 3 +/- 1.7 and 2.5 (range 2-7) days, respectively. There were no deaths, and the incidence of major complications was 8%.

CONCLUSION

The staging concept of LSG followed by LRYGBP is a safe and effective surgical approach for high-risk patients seeking bariatric surgery.

Plasticity of vagal afferents at the site of an incision in the wall of the stomach

Our objectives were to determine whether the vagal afferent innervation of the stomach reorganizes after surgery and to observe how different wound closure techniques might influence such a process. The smooth muscle wall of the stomach served as a model because it is densely innervated by vagal axons and is frequently compromised by gastric surgery. Male Sprague-Dawley rats were assigned to one of six groups: three groups served as controls in which the stomach was exposed surgically and a) subjected to no further manipulation, b) traumatized with suture needle punctures of the muscle wall, or c) insulted by the placement of knotted suture thread in the stomach muscle; three surgical groups received a 1.0 cm incision through the ventral muscle wall of the stomach that was closed using either a) absorbable sutures, b) fibrin glue, or c) n-butyl cyanoacrylate. Rats were killed 4 to 7 months post-surgery. Prior to euthanasia, Micro-Ruby was injected into the left nodose ganglion of each rat to label vagal afferent axons and terminals. Twelve days post-injection, the stomachs were processed for microscopy. All groups recovered quickly from surgery, without differences in body weight. The presence of suture material in the muscle wall of the stomach was sufficient to produce reorganization of nearby vagal afferents. In addition, we observed that an incision of the smooth muscle wall of the stomach and the associated damage to vagal afferents provoked reorganization and regeneration of vagal afferents. Vagal remodeling at the incision was characteristic of axonal patterns found in neuromas (unlike the organized regeneration and differentiation that can occur after axotomy central to the target organ). Vagal afferent terminals located at the site of the incision were free nerve endings and growth cone profiles, and not the characteristically complex end organs normally found in the smooth muscle. Finally, the pattern of vagal plasticity was influenced by the wound closure technique used. Overall, the remodeling of afferents was aberrant in nature, and such neural pathology could contribute to the neuropathic symptoms and hyperalgesias associated with gastrointestinal trauma and bariatric surgery.

Prevention of intra-abdominal adhesions using the antiangiogenic COX-2 inhibitor celecoxib

OBJECTIVE

To determine the effects of COX-2 specific inhibitors on postoperative adhesion formation.

SUMMARY AND BACKGROUND DATA

Intra-abdominal adhesions are the major cause of intestinal obstruction and secondary infertility after surgical procedures. Because adhesion synthesis requires angiogenesis, and cyclooxygenase-2 enzyme (COX-2) inhibitors have antiendothelial activity, we tested COX-2 inhibitors in a murine model of intra-abdominal adhesion formation.

METHODS

A silicone patch was secured to the lateral abdominal wall of groups of C57BL/6 mice, followed by cecal abrasion to promote adhesion formation. Beginning on the day of surgery, mice were treated with the selective COX-2 agents, celecoxib or rofecoxib, and the nonspecific COX inhibitors, aspirin, naproxen, ibuprofen, or indomethacin. Animals were treated for 10 days and killed. A second group (celecoxib, rofecoxib, aspirin) was treated for 10 days and observed for an additional 25 days. After treatment, intra-abdominal adhesions were scored using a standard method. The patch was subjected to immunohistochemistry with the endothelial-specific marker, CD31.

RESULTS

Animals treated with selective and nonselective COX-2 inhibitors, except aspirin, had significantly fewer adhesions than control animals. Celecoxib produced a maximal reduction in adhesion formation compared with rofecoxib and the nonselective COX-2 inhibitors at 10 days. After 25 days, celecoxib and rofecoxib, but not aspirin, had fewer adhesions than control mice. Adhesions from mice treated with celecoxib had reduced microvessel density compared with rofecoxib, the nonselective COX inhibitors, and control animals.

CONCLUSIONS

Selective COX-2 inhibitors, in particular celecoxib, provide durable inhibition of intra-abdominal adhesions through an antiangiogenic mechanism.

Mesothelial cell sheets cultured on fibrin gel prevent adhesion formation in an intestinal hernia model

In the present study, we examined a novel technique to prevent adhesion formation in a rat intestinal hernia model with mesothelial cell sheets cultured on fibrin gel. Mesothelial cells were obtained from isologous rats by enzymatic disaggregation of mesentery and cultured on fibrin gel. Electron microscopy revealed that these cultured cells form contiguous monolayer cell sheets with well-developed microvilli. These tissue-engineered constructs were grafted in vivo to an intestinal hernia model that results in regular surgical adhesions without treatment. Five days postgrafting, rats were sacrificed. Adhesion formation was not observed in rats grafted with the constructs, whereas severe adhesions were observed in all control rats. Constructs seeded with mesothelial cells isolated from EGFP-transgenic rats clearly revealed that grafted mesothelial cells remained at the host tissue site even after fibrin scaffold degradation. These cells developed more abundant microvilli in vivo than those in vitro. These results show that cultured mesothelial cell sheets are effective in preventing adhesion formation and should reduce postoperative complications caused by adhesion formation.

Induction and assessment methods used in experimental adhesion studies

Infertility and intestinal obstruction are well-known complications, arising from adhesion formation after intra-abdominal operations. Basic principles of adhesion formation have been found through animal studies. In addition, examination of agents for the prevention of adhesions can be easily made using experimental studies. However, lack of uniformity in study design makes assessment of the efficacy of any prophylactic regimen difficult. In this review, the material and methods used in experimental studies designed for adhesion formation or prevention were evaluated in detail, with experimental studies published in the literature from 1960 to 2003 being evaluated. Several methods for adhesion induction have been described in the literature. Severity of the adhesion varies from method to method, with the main problem being the lack of uniform expression of study results. Extensive use of complex adhesion classification systems should be used to resolve this discordance between experimental studies.

Possibilities and Limitations of Fibrin Glue Usage in Nephron-Sparing Surgery: Experimental Study

INTRODUCTION

The possibilities and limitations of fibrin glue (FG) usage in nephron-sparing surgery were studied.

MATERIALS AND METHODS

A prospective experimental study was carried out in 50 pigs: 30 with polar resection, and 20 with mediorenal wedge resection of the kidney. Hemostatic sutures, FG, and FG with a muscle 'cup' in animals with polar resection of the kidney were compared. FG and sutures in animals with the wedge resection of the kidney were studied as well. Bleeding, hot ischemia time, complication rate, and additional scarring were also analyzed.

RESULTS

Suture hemostasis is safe but with significant adverse effects in both polar and wedge resection of kidney. FG was not efficient as a sole hemostatic agent for polar resection. It was as efficient as hemostatic suture for wedge resection of the kidney. FG with a muscle 'cup' on a pole of the kidney achieved good results in animals with polar resection of the kidney. Histological analysis confirmed better results with FG because of both the less intense and smaller area of additional scarring.

CONCLUSION

FG is a reliable and efficient hemostatic agent for nephron-sparing surgery whenever both sided gluing is possible.

Expression of transforming growth factor-beta and extracellular matrix by human peritoneal mesothelial cells and by fibroblasts from normal peritoneum and adhesions: effect of Tisseel

We have previously shown that fibroblasts obtained from adhesions produce greater amounts of transforming growth factor-beta 1 (TGF-beta1) and extracellular matrix (ECM) molecules than normal fibroblasts isolated from normal peritoneum. The purpose of the current studies was to examine the effect of Tisseel (Baxter Healthcare Corporation, Glendale, CA), a fibrin sealant containing fibrinogen, aprotinin (a protease inhibitor), thrombin, and CaC1(2), on TGF-beta1 and ECM production by human peritoneal mesothelial cells, normal peritoneal fibroblasts, and adhesion fibroblasts. Multiplex reverse transcription-polymerase chain reaction using beta-actin as a housekeeping gene was used to determine mRNA levels of TGF-beta1 and ECM in these cells at 6, 12, 24, and 48 hours under normoxic conditions in the following treatment groups : fibrin sealant (Tisseel) alone; fibrin sealant with the two components diluted 1 : 2; fibrin sealant with the sealer protein component reconstituted without aprotinin (a protease inhibitor); fibrin sealant with the sealer protein component reconstituted without aprotinin (and both components diluted 1 : 2); fibrin sealant components diluted to physiologic concentrations; and control (culture media). The test compositions had little effect on TGF-beta1 mRNA expression in mesothelial cells and normal peritoneal fibroblasts, but resulted in a marked reduction of TGF-beta1 from adhesion fibroblasts. Expression of type I collagen by human peritoneal mesothelial cells was not detected; the compositions reduced type I collagen mRNA expression by both types of fibroblasts. Type III collagen was detected at six hours, and increased approximately 50 percent by culturing for 48 hours. Tisseel at full strength and with both components diluted 1 : 2 initially increased type III collagen mRNA levels; in contrast, type III collagen mRNA levels were reduced in mesothelial cells by the fibrin sealant without aprotinin at both concentrations and at physiologic concentrations. In both types of fibroblasts, the Tisseel compositions reduced type III collagen mRNA expression. Fibronectin mRNA were transiently reduced at six hours by approximately 50 percent in the presence of the Tisseel components, but then returned to control levels. Fibronectin mRNA levels were not altered in normal peritoneal fibroblasts, but were reduced by all but the physiologic concentration in adhesion fibroblasts. Tisseel may modulate human peritoneal mesothelial cell, normal peritoneal fibroblast, and adhesion fibroblast function. These results suggest that fibrin sealant prepared from the Tisseel kit without aprotinin has the ability to reduce ECM and TGF-beta1 mRNA levels, especially from adhesion fibroblasts, which may indicate a role in reduction of postoperative adhesion development.

Construction of a Transplantable Tissue-Engineered Artificial Peritoneum

BACKGROUND

Peritoneal defects lead to serious postoperative problems. Thus the development of physiological material to cover peritoneal defects is very desirable.

AIM

The aim of this study was to develop a transplantable artificial peritoneum.

METHOD

The artificial peritoneum consisted of collagen gel, fibroblasts, and mesothelial cells, and histological features were analyzed. The artificial peritoneum at the site of a peritoneal defect in the rat was transplanted to the abdominal wall.

RESULTS

Histological examination revealed that the artificial peritoneum consisted of a flat mesothelial monolayer upon a stromal matrix. All transplanted artificial peritoneums adapted well to the host and prevented severe adhesion.

CONCLUSION

Our artificial peritoneum may be a useful transplantable bioengineered material for repair of surgical peritoneal defects.

Effect of Tisseel® on expression of tissue plasminogen activator and plasminogen activator inhibitor-1

OBJECTIVE

To examine the effect of fibrin sealant on mRNA expression of factors regulating plasminogen activator activity in human peritoneal cells. Plasminogen activator activity is thought to play a pivotal role in degradation of the proteinaceous mass that develops after surgical procedures. Reduction of plasminogen activator activity, as occurs with tissue trauma, results in increased postoperative adhesion development.

DESIGN

Tissue culture for 6, 12, 24, and 48 hours.

SETTING

University research laboratory.

PATIENTS

Source of mesothelial cells with fibroblasts.

INTERVENTION(S)

Measurement of mRNA expression of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1).

MAIN OUTCOME MEASURE(S)

Multiplex reverse transcriptase/polymerase chain reaction (RT/PCR) was used to determine relative change in t-PA and PAI-1 mRNA levels under six conditions: [1]. fibrin sealant (Tisseel); [2]. fibrin sealant (Tisseel) two components diluted 1:2; [3]. fibrin sealant (Tisseel) sealer protein component reconstituted without aprotinin (a protease inhibitor); [4]. fibrin sealant (Tisseel) sealer protein component reconstituted without aprotinin, both components diluted 1:2; [5]. fibrin sealant (Tisseel) components diluted to physiologic concentrations; and [6] control (culture media).

RESULTS

The mRNA levels of t-PA and PAI-1 by human peritoneal cells were unchanged during 48 hours. In mesothelial cells, the addition of the compositions increased t-PA mRNA levels. A selective increase was observed in the normal peritoneal fibroblasts at the later time points; similar increases were identified in adhesion fibroblast cultures. In mesothelial cells, the more concentrated compositions generally increased PAI-1 mRNA above control levels, whereas in normal peritoneal fibroblasts PAI-1 levels generally remained unchanged. In contrast, in adhesion fibroblasts, PAI-1 levels decreased over time with treatment.

CONCLUSION(S)

Fibrin sealant, in the presence and absence of aprotinin, increases both t-PA and PAI-1 expression by human peritoneal cells; changes not seen with physiologic concentrations of fibrin sealant. These observations suggest that in addition to its ability to help achieve hemostasis, fibrin sealant affects the healing process by altering components of the plasminogen activator system, which may be of benefit in the reduction of postoperative adhesions.

Effect of fibrin sealant composition on human neutrophil chemotaxis

The use of fibrin sealants offers one of the most physiologically compatible approaches to preventing postoperative adhesions. Although a number of fibrin sealant formulations have been developed, little is known about how the various components of these preparations affect the wound-healing process. Because one of the key steps in wound healing is the migration of phagocytic leukocytes, such as neutrophils, into the site of injury, we performed studies to characterize systematically the effects of various fibrin sealant components on neutrophil chemotaxis. Using a transwell chemotaxis assay, we found that increasing fibrin concentration resulted in an inhibition of the ability of the cells to migrate through the clots in a dose-dependent manner, and at fibrin clot concentrations >2.0 mg/mL chemotaxis was completely blocked. Factor XIII crosslinking of the clots also had a significant impact on neutrophil chemotaxis, and sealant preparations deficient in Factor XIII allowed neutrophil migration at much higher fibrin concentrations. The presence of various other fibrin sealant components such as plasminogen and fibrinolysis inhibitors (aprotinin and tranexamic acid) did not have any significant effects on the ability of neutrophils to migrate through fibrin clots as compared to control clots without these components. Overall, these studies show that the composition of fibrin sealant preparations can significantly affect neutrophil migration into the site of injury, which could possibly influence the wound healing process.

Tropical application of halcinonide cream reduces the severity and incidence of intraperitoneal adhesions in a rat model

BACKGROUND

Systemic or intraperitoneal administration of corticosteroids has been reported to have conflicting effects on the prevention of peritoneal adhesions. Painting corticosteroid cream directly on the likely site of adhesion formation, owing to its high concentrations and persistent effects, may be a promising approach to prevent peritoneal adhesion formation.

METHODS

Adhesions were induced by abrading of the cecum, followed by dropping of 95% ethanol. Sixty Wistar rats were randomly allocated to two control groups with no further treatment of the cecum and to two therapy groups treated with 0.1% halcinonide cream painted directly on the damaged surface of the cecum. After 3 and 7 days, adhesion scores, adhesion incidence, and intraperitoneal leukocytes were evaluated.

RESULTS

On both postoperative days 3 and 7, halcinonide cream resulted in a significant decrease in mean adhesion scores (6.80 versus 0.67, 10.40 versus 1.26; P <0.001, P <0.001, respectively). The adhesion incidence was 43.3% for the therapy groups and 100% for controls (P <0.01). On day 3, the total numbers of intraperitoneal leukocytes were 120.73 +/- 24.01 millions for the therapy groups and 270.40 +/- 34.68 for controls (P <0.001).

CONCLUSIONS

Painting halcinonide cream directly on the damaged surface of the cecum could effectively reduce the severity and incidence of adhesion, possibly by suppression of early inflammatory exudate and of late fibroblast invasion and proliferation.