Prevention of adhesions by sodium chromoglycate, dexamethasone, saline and aprotinin after pelvic surgery

Hemoadhican-Based Bioabsorbable Hydrogel for Preventing Postoperative Adhesions

Postoperative peritoneal adhesions are a prevalent clinical issue following abdominal and pelvic surgery, frequently resulting in heightened personal and societal health burdens. Traditional biomedical barriers offer limited benefits because of practical challenges for doctors and their incompatibility with laparoscopic surgery. Hydrogel materials, represented by hyaluronic acid gels, are receiving increasing attention. However, existing antiadhesive gels still have limited effectiveness or carry the risk of complications in clinical applications. Herein, we developed a novel hydrogel using polysaccharide hemoadhican (HD) as the base material and polyethylene glycol diglycidyl ether (PEGDE) as the cross-linking agent. The HD hydrogels exhibit appropriate mechanical properties, injectability, and excellent cytocompatibility. We demonstrate resistance to protein adsorption and L929 fibroblast cell adhesion to the HD hydrogel. The biodegradability and efficacy against peritoneal adhesion are further evaluated in C57BL/6 mice. Our results suggest a potential strategy for anti-postoperative tissue adhesion barrier biomaterials.

Postsurgical Adhesions: Is There Any Prophylactic Strategy Really Working?

Postoperative adhesions are a frequent complication encountered after surgical procedures, mainly after intraperitoneal interventions. To this day, the pathophysiological mechanism behind the process of adhesions formation is not completely known. There are many strategies proposed as prophylaxis methods, involving surgical techniques, drugs or materials that prevent adhesions and even state of the art technologies such as nanoparticles or gene therapy. The aim of our review is to present these innovative approaches and techniques for postoperative adhesions prevention. After a thorough scientific database query, we selected 84 articles published in the past 15 years that were relevant to our topic. Despite all the recent groundbreaking discoveries, we are at an early stage of understanding the complexity of the adhesion formation mechanism. Further investigations should be made in order to create an ideal product for safe clinical use for prevention.

Self-healing, injectable hydrogel based on dual dynamic covalent cross-linking against postoperative abdominal cavity adhesion

Clinically, increasing the peritoneal barrier is an effective adjunct to reducing postoperative peritoneal adhesion. This study presents a facile template for preparing a supramolecular hybrid hydrogel through dynamic covalent cross-linking between carboxymethyl chitosan (CMCS), 2-formylphenylboronic acid (2-FPBA), and quercetin (Que). The as-prepared complex CMCS/2-FPBA/Que (CFQ) hydrogel exhibited favorable antibacterial, anti-inflammatory, and antioxidant effects. A L929 cytotoxicity evaluation confirmed the favorable cytocompatibility of the CFQ hydrogel. The postoperative anti-adhesion ability of the CFQ hydrogel was further evaluated in rats with lateral wall defects and cecal abrasions. Compared with control groups, the tissue adhesion rate was significantly reduced by increasing the Que concentration in all the hydrogel-treated groups. Additionally, the sustained-release time of the C3F0.8Q0.08 hydrogel can exceed 14 days, which is highly desirable for clinical wound treatment. STATEMENT OF SIGNIFICANCE: Postoperative adhesions are a very common postoperative complication that seriously affects the quality of life of patients. The currently commonly used methods for preventing adhesion mainly use degradable barrier materials for physical separation. In this study, we prepared a dual dynamic covalently cross-linked CFQ hydrogel, which is not only degradable and injectable, but also has multiple properties such as antibacterial, antioxidant and anti-inflammatory, which can effectively prevent postoperative adhesion and promote wound healing.

Hotmelt tissue adhesive with supramolecularly-controlled sol-gel transition for preventing postoperative abdominal adhesion

Postoperative adhesion is a serious and frequent complication, but there is currently no reliable anti-adhesive barrier available due to low tissue adhesiveness, undesirable chemical reactions, and poor operability. To overcome these problems, we report a single-syringe hotmelt tissue adhesive that dissolves upon warming over 40 °C and coheres at 37 °C as a postoperative barrier. Tendon-derived gelatin was conjugated with the ureidopyrimidinone unit to supramolecularly control the sol-gel transition behavior. This functionalization improved bulk mechanical strength, tissue-adhesive properties, and stability under physiological conditions through the augmentation of intermolecular hydrogen bonding by ureidopyrimidinone unit. This biocompatible adhesive prevented postoperative adhesion between cecum and abdominal wall in adhesion models of rats. This hotmelt tissue adhesive has enormous potential to prevent postoperative complications and may contribute to minimally invasive surgery. STATEMENT OF SIGNIFICANCE: There is a strong need to develop medical tissue adhesives with high biocompatibility, tissue adhesiveness, and operatability to prevent postoperative complications. In this report, single syringe, hotmelt-type tissue adhesive was developed by controlling sol-gel transition behavior of gelatin through supramolecular approach. The functionalization of gelatin with quadruple hydrogen bonding improved key features necessary for anti-adhesive barrier including bulk mechanical strength, tissue adhesive property, stability under physiological conditions, and anti-adhesive property. The hotmelt tissue adhesive can be used for a sealant, hemostatic reagent, and wound dressing to prevent postoperative complications including delayed bleeding, perforation, and inflammation and contribute to minimally invasive surgery.

Prevention of Postsurgical Abdominal Adhesion Using Electrospun TPU Nanofibers in Rat Model

Intra-abdominal adhesions following surgery are a challenging problem in surgical practice. This study fabricated different thermoplastic polyurethane (TPU) nanofibers with different average diameters using the electrospinning method. The conditions were evaluated by scanning electron microscopy (SEM), atomic force microscope (AFM), and Fourier transform infrared spectrometer (FTIR) analysis. A static tensile test was applied using a strength testing device to assess the mechanical properties of the electrospun scaffolds. By changing the effective electrospinning parameters, the best quality of nanofibers could be achieved with the lowest bead numbers. The electrospun nanofibers were evaluated in vivo using a rat cecal abrasion model. The macroscopic evaluation and the microscopic study, including the degree of adhesion and inflammation, were investigated after three and five weeks. The resultant electrospun TPU nanofibers had diameters ranging from about 200 to 1000 nm. The diameters and morphology of the nanofibers were significantly affected by the concentration of polymer. Uniform TPU nanofibers without beads could be prepared by electrospinning through reasonable control of the process concentration. These nanofibers' biodegradability and antibacterial properties were investigated by weight loss measurement and microdilution methods, respectively. The purpose of this study was to provide electrospun nanofibers having biodegradability and antibacterial properties that prevent any adhesions or inflammation after pelvic and abdominal surgeries. The in vivo experiments revealed that electrospun TPU nanofibers reduced the degree of abdominal adhesions. The histopathological study confirmed only a small extent of inflammatory cell infiltration in the 8% and 10% TPU. Conclusively, nanofibers containing 8% TPU significantly decreased the incidence and severity of postsurgical adhesions, and it is expected to be used in clinical applications in the future.

Prevention of Post-Operative Adhesions: A Comprehensive Review of Present and Emerging Strategies

Post-operative adhesions affect patients undergoing all types of surgeries. They are associated with serious complications, including higher risk of morbidity and mortality. Given increased hospitalization, longer operative times, and longer length of hospital stay, post-surgical adhesions also pose a great financial burden. Although our knowledge of some of the underlying mechanisms driving adhesion formation has significantly improved over the past two decades, literature has yet to fully explain the pathogenesis and etiology of post-surgical adhesions. As a result, finding an ideal preventative strategy and leveraging appropriate tissue engineering strategies has proven to be difficult. Different products have been developed and enjoyed various levels of success along the translational tissue engineering research spectrum, but their clinical translation has been limited. Herein, we comprehensively review the agents and products that have been developed to mitigate post-operative adhesion formation. We also assess emerging strategies that aid in facilitating precision and personalized medicine to improve outcomes for patients and our healthcare system.

Use of hypertonic glucose (10%) in the prevention of postoperative adhesions in rats

Purpose

To evaluate the efficacy of hypertonic glucose (10%), alone or in combination with the corticoid dexamethasone, to prevent peritoneal adhesion following hysterectomy in rats.

Methods

Forty-two adult rats underwent hysterectomy with peritoneal lavage: G1 – glucose (10%); G2 – glucose (10%) and dexamethasone 3 mg·kg^–1; and G3 – physiological saline (PS) 0.9%.

Results

In the macroscopic analysis after 14 days, G1 had a median score of 1, G2 of 1, and G3 of 2.5 (p < 0.0001), G3 compared to G1 and G2. There was no difference between groups after 28 days. In the microscopic analysis, the median vascular proliferation after 14 days was 2 for G1, 1 for G2, and 3 for G3 (p = 0.0037, G3 vs. G1 and G2). After 28 days, G1 showed a median vascular proliferation score of 2, G2 of 2.5, and G3 of 3 (p < 0.0001, G3 vs. G1 and G2). Regarding the inflammatory reaction after 14 days, G1 had a median score of 2, G2 of 1, and G3 of 3 (p = 0.7916). After 28 days, G1 had a median score of 0.5 (0–1.75), G2 of 1.5, and G3 of 2.5 (p < 0.0001, G3 vs. the others and G2 vs. G1). In the evaluation of fibrosis after 14 days, G1 had a median score of 1, G2 of 1, and G3 of 2.5 (p < 0.0001, G3 vs. G1and G2). After 28 days, G1 had a median fibrosis score of 1, G2: 2, and G3: 2.5 (p < 0.0001), G3 vs. the others andG2 vs. G1).

Conclusions

The use of hypertonic glucose (10%) solution seems to reduce macroscopic and microscopic pelvic adhesions.

Antibacterial, hemostasis, adhesive, self-healing polysaccharides-based composite hydrogel wound dressing for the prevention and treatment of postoperative adhesion

Herein, we fabricated novel self-healing, in situ injectable, biodegradable, and non-toxic hydrogels anti-adhesion barrier materials composed of N, O-carboxymethyl chitosan (N,O-CS) and oxidized dextran (ODA) without requiring any chemical cross-linking agent or external stimuli triggers for the prevention and treatment of post-operative peritoneal adhesions. The N,O-CS/ODA hydrogels have a good suitable gelation time, good cytocompatibility and hemocompatibility, good antibacterial activity, excellent biodegradable and biocompatible, and can effectively inhibit the adhesion of fibroblasts to the wound, thereby suggesting that N,O-CS/ODA hydrogels are suitable for preventing post-operative adhesion. Meanwhile, a rat injury sidewall-cecum abrasion model is developed to investigate the efficacy of these hydrogels in achieving post-operative anti-adhesion. A significant reduction of peritoneal adhesions (10% rat with lower score adhesion) is observed in the N,O-CS/ODA-hydrogel-treated group compared with the commercial hydrogel and control groups. These results demonstrated that N,O-CS/ODA hydrogel could effectively prevent post-operative peritoneal adhesion without side effects. Therefore, the N,O-CS/ODA hydrogels with multi-functional properties exhibit great potential for the prevention and treatment of postoperative adhesion.

Fouling-resistant zwitterionic polymers for complete prevention of postoperative adhesion

Postoperative adhesions are most common issues for almost any types of abdominal and pelvic surgery, leading to adverse consequences. Pharmacological treatments and physical barrier devices are two main approaches to address postoperative adhesions but can only alleviate or reduce adhesions to some extent. There is an urgent need for a reliable approach to completely prevent postoperative adhesions and to significantly improve the clinical outcomes, which, however, is unmet with current technologies. Here we report that by applying a viscous, cream-like yet injectable zwitterionic polymer solution to the traumatized surface, postoperative adhesion was completely and reliably prevented in three clinically relevant but increasingly challenging models in rats. The success rate of full prevention is over 93% among 42 animals tested, which is a major leap in antiadhesion performance. Clinically used Interceed film can hardly prevent the adhesion in any of these models. Unlike current antiadhesion materials serving solely as physical barriers, the "nonfouling" zwitterionic polymer functioned as a protective layer for antiadhesion applications with the inherent benefit of resisting protein/cell adhesions. The nonfouling nature of the polymer prevented the absorption of fibronectins and fibroblasts, which contribute to the initial and late-stage development of the adhesion, respectively. This is the key working mechanism that differentiated our "complete prevention" approach from current underperforming antiadhesion materials. This work implies a safe, effective, and convenient way to fully prevent postoperative adhesions suffered by current surgical patients.

Biologically Targeted Photo-Crosslinkable Nanopatch to Prevent Postsurgical Peritoneal Adhesion

Peritoneal adhesion occurs in a majority of patients following abdominal surgery and can result in significant side effects and complications. Current strategies to minimize adhesions involve the use of nontargeted anatomical barriers that are either inefficient in protecting injured areas or lacking the adequate residence time to prevent adhesions. Herein, the development of a biologically targeted photo-crosslinkable nanopatch (pCNP) is reported that can prevent postsurgical adhesion. It is demonstrated that pCNP can form a compact protective barrier over surfaces with exposed collagen IV. Using a rat parietal peritoneal excision adhesion model, it is showed that pCNP is highly effective and safe in preventing postsurgical adhesions. This work presents a novel approach to preventing peritoneal adhesion with nanomaterials.

Effects of Streptokinase and Normal Saline on the Incidence of Intra-abdominal Adhesion 1 Week and 1 Month after Laparotomy in Rats

Background:

Intra-abdominal adhesions after surgery are usually in the form of bands and can annoy the patient throughout life causing repeated surgical procedures. Therefore, any action to prevent adhesions after surgery can increase longevity and quality of life. For this aim, this study investigates the effect of streptokinase and normal saline on the 7^th day and 1 month after laparotomy.

Materials and Methods:

Experimental study was conducted on thirty healthy male Wistar rats weighing 200–250 g with age of 3 months divided into three groups of 10. Group I: No treatment, Group II: Received normal saline, and Group III: Received normal saline and streptokinase at the same time. One week and 1 month after laparotomy, the frequency of the presence or absence of adhesion bands was performed by a person who was unaware of the sample grouping. The collected information was analyzed with the SPSS software (version 16; SPSS Inc., Chicago, IL, USA).

Results:

Adhesion frequency was found to be 20% on the 7^th day (early) and 1 month after laparotomy (late) for Group 1, and it was 40% on early and late for Group II, while 0% on the early and late for Group III. Hence, in the group receiving streptokinase, no early or late adhesion was observed; therefore, it had a significant role in the prevention of intra-abdominal adhesions (P < 0.05). However, adhesions in the group receiving normal saline had no remarkable difference with the group receiving no drug (P > 0.05).

Conclusion:

According to the results of our study, we believe that streptokinase could be a good antiadhesive agent considering its effectiveness.

Targeting lysyl oxidase reduces peritoneal fibrosis

Background

Abdominal surgery and disease cause persistent abdominal adhesions, pelvic pain, infertility and occasionally, bowel obstruction. Current treatments are ineffective and the aetiology is unclear, although excessive collagen deposition is a consistent feature. Lysyl oxidase (Lox) is a key enzyme required for crosslinking and deposition of insoluble collagen, so we investigated whether targeting Lox might be an approach to reduce abdominal adhesions.

Methods

Female C57Bl/6 mice were treated intraperitoneally with multiwalled carbon nanotubes (NT) to induce fibrosis, together with chemical (ß-aminoproprionitrile–BAPN) or miRNA Lox inhibitors, progesterone or dexamethasone. Fibrotic lesions on the diaphragm, and expression of fibrosis-related genes in abdominal wall peritoneal mesothelial cells (PMC) were measured. Effects of BAPN and dexamethasone on collagen fibre alignment were observed by TEM. Isolated PMC were cultured with interleukin-1 alpha (IL-1α) and progesterone to determine effects on Lox mRNA in vitro.

Results

NT-induced fibrosis and collagen deposition on the diaphragm was ameliorated by BAPN, Lox miRNA, or steroids. BAPN and dexamethasone disrupted collagen fibres. NT increased PMC Lox, Col1a1, Col3a1 and Bmp1 mRNA, which was inhibited by steroids. Progesterone significantly inhibited IL-1α induced Lox expression by PMC in vitro.

Conclusion

Our results provide proof-of-concept that targeting peritoneal Lox could be an effective approach in ameliorating fibrosis and adhesion development.

Biodegradable and injectable thermoreversible xyloglucan based hydrogel for prevention of postoperative adhesion

Peritoneal adhesion is very common after abdominal and pelvic surgery, which leads to a variety of severe complications. Although numerous pharmacological treatments and barrier-based devices have been investigated to minimize or prevent postoperative adhesion, the clinical efficacy is not very encouraging. In this work, a biodegradable and thermoreversible galactose modified xyloglucan (mXG) hydrogel was developed and the efficacy of mXG hydrogel in preventing postoperative peritoneal adhesion was investigated. The 4% (w/v) mXG solution was a free flowing sol at low temperature, but could rapidly convert into a physical hydrogel at body temperature without any extra additives or chemical reactions. In vitro cell tests showed that mXG hydrogel was non-toxic and could effectively resist the adhesion of fibroblasts. Moreover, in vitro and in vivo degradation experiments exhibited that mXG hydrogel was degradable and biocompatible. Finally, the rat model of sidewall defect-cecum abrasion was employed to evaluate the anti-adhesion efficacy of the mXG hydrogel. The results demonstrated that mXG hydrogel could effectively prevent postoperative peritoneal adhesion without side effects. The combination of suitable gel temperature, appropriate biodegradation period, and excellent postoperative anti-adhesion efficacy make mXG hydrogel a promising candidate for the prevention of postsurgical peritoneal adhesion.

STATEMENT OF SIGNIFICANCE

Despite numerous drugs or barrier-based devices have been developed to prevent postoperative adhesion, few solutions have proven to be uniformly effective in subsequent clinical trials. In the present study, we developed a biodegradable and thermoreversible galactose modified xyloglucan (mXG) hydrogel by green enzymatic reaction without using any organic reagents. The developed physical mXG hydrogel not only showed excellent injectability, appropriate gelation time and temperature, but also exhibited excellent biocompatibility and biodegradability both in vitro and in vivo. In addition, mXG hydrogel was easy to handle and could effectively prevent postoperative adhesion without side effects in a rat model of sidewall defect-bowel abrasion. Our study provide a safe and effective postoperative anti-adhesion material which may have potential applications in clinical practice.

Effect of the Bioadhesive, BioGlue, on Impaired Colonic Anastomose Healing in Rats

Colonic anastomotic leakage is still a problem in general surgery practice. We sought to investigate the effect of a new tissue adhesive, BioGlue, on the healing of normal and impaired colonic anastomoses. Sixty-four rats were randomized into 4 groups. In all animals, a 1-cm segment of the left colon was resected, and an end-to-end sutured anastomosis was created. Animals were then divided into 2 groups: normal and impaired anastomosis. These 2 groups were further subdivided into 2 additional groups: animals that received BioGlue and those that did not. All rats received intraperitoneal injections of either 0.9% NaCl or 5-fluorouracil (5-FU). Anastomotic evaluation was done 7 days after surgery. Macroscopic healing, mechanical strength, and histopathologic healing parameters were evaluated. Leakage of the anastomosis was significantly higher in rats in the impaired group compared with those in the BioGlue groups (P = 0.043). The adhesion formation score was significantly higher in rats in the impaired anastomosis group compared with the other groups. Bursting pressures were significantly lower in the impaired anastomosis group than in the other ones (P = 0.001). Neoangiogenesis and fibroblast activity were different among the groups (P = 0.001). Inflammatory cell infiltration and collagen deposition did not differ among the groups (P = 0.07). Immediate postoperative intraperitoneal administration of 5-FU after colonic anastomosis inhibits intestinal wound healing. Covering colon anastomoses with BioGlue after suturing conferred beneficial effect on healing.

Adhesions after abdominal surgery: a systematic review of the incidence, distribution and severity

Abdominal adhesions are associated with increased postoperative complications, cost and workload. We performed a systematic review with statistical pooling to estimate the formation rate, distribution and severity of postoperative adhesions in patients undergoing abdominal surgery. A literature search was carried out for all articles reporting on the incidence, distribution and severity of adhesions between January 1990 and July 2011. Twenty-five articles fulfilled the inclusion criteria. The weighted mean formation rate of adhesions after abdominal surgery was 54 % (95 % confidence interval [CI] 40-68 %), and was 66 % (95 % CI 38-94 %) after gastrointestinal surgery, 51 % (95 % CI 40-63 %) after obstetric and gynaecological surgery and 22 % (95 % CI 7-38 %) after urological surgery. The mean overall severity score was 1.11 ± 0.98 according to the Operative Laparoscopy Study Group classification. Laparoscopic surgery reduced the adhesion formation rate by 25 % and decreased the adhesion severity score (laparoscopic; 0.36 ± 0.69 vs. open; 2.14 ± 0.84) for gastrointestinal surgery. Our results demonstrate that the incidence and severity of abdominal adhesions varies between surgical specialties and procedures. An increased awareness of adhesions can help in identifying the underlying mechanisms of adhesion formation and novel therapeutic approaches, while also improving the surgical consent process.

Intra-abdominal adhesions: cellular mechanisms and strategies for prevention

Postoperative intra-abdominal adhesions represent a serious clinical problem. In this review, we have focused on recent progress in the cellular and humoral mechanisms underpinning adhesion formation, and have reviewed strategies that interfere with these pathways as a means to prevent their occurrence. Current and previous English-language literature on the pathogenesis of adhesion formation was identified. As the burden of surgical disease in the world population increases, and the frequency of reoperation increases, prevention of adhesion formation has become a pressing goal in surgical research.

A method for the consistent creation and quantitative testing of postoperative pelvic adhesions in a porcine model

INTRODUCTION

The assessment of methods for the prevention of postoperative pelvic adhesions is hampered by the lack of a quantifiable adhesion measurement technique. Currently available methods for adhesion model assessment rely on qualitative grading scales; a quantitative method would have many attendant benefits, including standardized reporting.

METHODS

A technique was developed to generate consistent and significant adhesions in a swine model that are suitable for quantitative assessment using a Material Testing System (MTS) machine platform. In this method, the uterine horns are cannulated and then attached to the pelvic sidewall using loose silk sutures. The underlying sidewall and adjacent uterine serosa are injured with electrocautery. Following a two-week survival the entire complex of uterine horn and sidewall are excised en bloc and prepared for MTS testing.

RESULTS

Extrication of the adhesion, as measured by the MTS platform, generates a quantitative assessment of adhesion strength that can be scaled and analyzed to produce several continuous variable descriptions.

DISCUSSION

This technique represents a novel quantitative method for adhesion assessment in an animal model. This quantitative technique may then be applied to accurately assess a range of adhesion prevention techniques, producing results which can be standardized for comparison.

A novel laparoscopic suction device for applying precise aspiration during laparoscopic surgery: sponge-tip suction tube

Aspiration of the intra-abdominal fluid and debris is usually needed during different stages of the operation. This is necessary to protect the intra-abdominal space from contamination and/or to remove blood or tissue fluids occurring during the operation. It is also essential for obtaining a clean surgical area. Aspiration of the intra-abdominal fluid is relatively more difficult in laparoscopic surgery because of the suctioning of the omentum and intestine with the aspirator. In this paper, we report on a new suction device (sponge tip suction tube; STST), which allows the surgeon easier suctioning of intra-abdominal fluid. STST has an additional sponge tip and air channel, which prevents the device from suctioning intra-abdominal organs, such as the intestine and omentum. We tested the efficacy of STST in a simulated intra-abdominal space, such as a large transparent plastic bag with fresh sheep intestine-omentum and with 2000 cc of physiologic saline solution and 14 mm Hg of air pressure. Whereas the suctioning of all the fluid was difficult and time consuming when the conventional suction unit was used, all of the saline solution was easily and quickly suctioned when STST was used. In conclusion, STST provides a safe, fast, and complete fluid extraction.

The preventive effect of Met-RANTES on postoperative intraperitoneal adhesion formation in the rat model

BACKGROUND

Chemokines are proinflammatory proteins that participate in immune and inflammatory responses through chemoattraction and leukocyte activation. The chemokine antagonist Met-RANTES (Regulated upon Activation Normal T cell Expressed and Secreted) has been shown to be efficacious in decreasing inflammation in several animal disease models. The purpose of this study was to investigate the effects of administration of Met-RANTES on intra-abdominal adhesion formation after abdominal operation.

MATERIALS AND METHODS

A 42 and 4-month-old female Wistar-Albino rats were subjected to standardized lesions by cauterization of the cecum and uterine horn. They were divided randomly into 3 groups containing 14 rats each: group 1 (control), operative procedure without further treatment; group 2 (Seprafilm), operative procedure with an antiadhesive membrane; 2 x 1 cm of Seprafilm was interposed beneath the peritoneal incision, and group 3 (Met-RANTES), operative procedure with the chemokine antagonist Met-RANTES. The extent and severity of adhesions at the operative site were evaluated. Light microscopic examination was performed to determine semiquantitative scores of VEGF expression.

RESULTS

Rats in the control group formed extensive adhesions. In comparison with the control group, the adhesion scores were significantly lower in the 2 other groups. The immunohistochemical grading scores of vascular endothelial growth factor correlated closely with the total adhesion scores and were less in groups 2 and 3 (P < .005).

CONCLUSIONS

Selective chemokine suppression with Met-RANTES seems to decrease rates, extent, and severity of postoperative intraperitoneal adhesions.

Effect of oral d-penicillamine vs. colchicine on experimentally induced peritoneal adhesions in rats

OBJECTIVE

To evaluate the effects of d-penicillamine on prevention or reduction of adhesion band formation and to compare its effects with those of colchicine in an animal model.

DESIGN

A prospective experimental study.

SETTING

Rats in an academic research environment.

ANIMAL(S)

Eighty female rats were randomly divided into four equal groups. In the end, group 4 was excluded because of high mortality rates.

INTERVENTION(S)

Adhesion bands were induced by intraperitoneal injection of 2.5 mL of a 10% sterile talc solution. The first group served as control, group 2 received oral D-penicillamine (35 mg/kg per day), group 3 received oral colchicines (0.02 mg/kg per day), and group 4 received both drugs for 3 consecutive weeks.

MAIN OUTCOME MEASURE(S)

Formation of adhesion bands was quantitatively graded according to the Nair classification.

RESULT(S)

The proportion of control rats with substantial adhesion bands was significantly higher than that of rats in groups 2 or 3 (84.2%, 20%, and 33.3%). No difference regarding the grades of adhesion bands was found between the D-penicillamine and colchicine groups.

CONCLUSION(S)

Oral D-penicillamine is as effective as oral colchicine in prevention of peritoneal adhesion band formation in rats. Use of D-penicillamine for this purpose should be weighed against its possible side effects.

Super-oxidized solution inhibits IgE-antigen-induced degranulation and cytokine release in mast cells

Activation of the high affinity IgE receptor (Fc epsilonRI) through IgE-antigen complexes induces mast cell degranulation, synthesis of lipid mediators and cytokine production. These effects are involved in Type I hypersensitivity reactions and controlling them has been the main objective of many anti-allergic therapies. Here we report that pretreatment of murine bone marrow derived mast cells (BMMC) with super-oxidized solution (SOS) inhibits Fc epsilonRI dependent-beta hexosaminidase and cytokine release. This effect is exerted without altering total protein tyrosine phosphorylation, MAPK activation, cytokine mRNA accumulation or calcium mobilization after Fc epsilonRI triggering. Our data suggest that this neutral pH-SOS acts like a mast cell-membrane stabilizer inhibiting the cell machinery for granule secretion without altering the signal transduction pathways induced by IgE-antigen receptor crosslinking.

Polymers in the prevention of peritoneal adhesions

Peritoneal adhesions are serious complications of surgery, and can result in pain, infertility, and potentially lethal bowel obstruction. Pharmacotherapy and barrier devices have reduced adhesion formation to varying degrees in preclinical studies or clinical trials; however, complete prevention of adhesions remains to be accomplished. We and others have hypothesized that the limitations of the two approaches could be overcome by combining their strengths in the context of controlled drug delivery. Here we review the role of polymeric systems in the prevention of peritoneal adhesions, with an emphasis on our recent work in developing and applying polymeric drug delivery systems such as nano- or microparticles, hydrogels, and hybrid systems for peritoneal use.

Prevention of peritoneal adhesions with an in situ cross-linkable hyaluronan hydrogel delivering budesonide

Peritoneal adhesions are tissue connections that form within the abdominopelvic cavity following surgery or other injuries. They can cause major medical complications. Barrier devices and pharmacological agents have been used to prevent adhesion formation, with mixed success. We hypothesize that an adhesion barrier which also delivers anti-adhesion drugs can address both physical and physiological causes for adhesion formation. Here, we describe an in situ cross-linking hyaluronan hydrogel (barrier device) containing the glucocorticoid receptor agonist budesonide. Budesonide was chosen because of the known role of inflammation in adhesion formation, hyaluronan because of its known biocompatibility in the peritoneum. The system, consisting of two cross-linkable precursor liquids, was applied using a double-barreled syringe, forming a flexible and durable hydrogel in less than 5 s. We applied this formulation or controls to the injured sites after the second injury in a severe repeat sidewall defect-cecum abrasion model of peritoneal adhesion formation in the rabbit. Large adhesions (median area 15.4 cm(2)) developed in all saline-treated animals. Adhesion formation and area were slightly mitigated in animals treated with budesonide in saline (median area 5.0 cm(2)) or the hydrogel without budesonide (median area 4.9 cm(2)). The incidence and area of adhesions were dramatically reduced in animals treated with budesonide in the hydrogel (median area 0.0 cm(2)). In subcutaneous injections in rats, budesonide in hydrogel reduced inflammation compared to hydrogel alone. In summary, budesonide in a hyaluronan hydrogel is easy to use and highly effective in preventing adhesions in our severe repeated injury model. It is a potentially promising system for post-surgical adhesion prevention, and suggests that the effectiveness of barrier devices can be greatly enhanced by concurrent drug delivery.

The effect of insulin-like growth factor I on healing of colonic anastomoses in cortisone-treated rats

PURPOSE

This study was designed to investigate whether intraperitoneally injected insulin-like growth factor I is able to protect colonic healing from the adverse effects of hydrocortisone therapy.

METHODS

Eighty female Wistar rats were randomized into four groups (20 rats each). After resection of a segment of transverse colon, an end-to-end anastomosis was performed. Hydrocortisone (5 mg/kg body weight) was injected intramuscularly in rats of cortisone (Group B) and insulin-like growth factor I + cortisone (Group D) groups once daily for seven days before and after the operation. Insulin-like growth factor I (2 mg/kg body weight) was intraperitoneally injected in rats of the insulin-like growth factor I (Group C) and the insulin-like growth factor I + Cortisone (Group D) groups immediately after operation and on the second, fourth, and sixth postoperative days. Rats were killed on the seventh postoperative day. Anastomoses were graded macroscopically and histologically, and bursting pressures and anastomotic hydroxyproline levels were recorded. Statistical analyses were performed by using Fisher's exact test for the comparison of proportions and ANOVA for the comparison of means among groups with subsequent post-hoc analysis using Bonferroni correction.

RESULTS

Leakage rate was significantly higher in the cortisone (Group B) group. Bursting pressures were significantly lower in the cortisone group, whereas they were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups (Group C and D). Histology revealed a significant decrease of inflammatory cell infiltration, neoangiogenesis, and fibroblast activity in the cortisone group compared with the control group, whereas these parameters were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups. Hydroxyproline levels were significantly higher in the insulin-like growth factor I and insulin-like growth factor I + cortisone groups.

CONCLUSIONS

Hydrocortisone inhibits the healing of colonic anastomoses. However, insulin-like growth factor I given intraperitoneally mediates the deleterious effects of cortisone and protects colonic healing in rats.

Effects of the intraperitoneal lornoxicam on the formation of intraperitoneal adhesions in rat peritonitis model

BACKGROUND

To investigate the effects of intraperitoneally administered lornoxicam on adhesion formation, bursting pressure, tissue antioxidant levels, morbidity and mortality after ileocolic anastomosis in a rat bacterial peritonitis model.

METHODS

Thirty-six rats were divided into three random groups. Bacterial peritonitis was induced by performing a cecal ligation and puncture, then the cecal was resected and ileocolic anastomosis was performed. Rats of groups 1, 2 and 3 were given 2 mL normal saline, 2 mL lornoxicam, and nothing, respectively. All groups were killed at day 14. Adhesions were scored, and the presence of intra-abdominal abscesses and fistulas were noted. Anastomotic healing was assessed by bursting pressure. Tissue antioxidant levels were tested from left abdominal walls.

RESULTS

One day after cecal ligation and puncture, microbiological examination showed polymicrobial bacterial peritonitis. The rats treated with lornoxicam had significantly lower adhesion scores than did the saline and nothing treated rats (P = 0.007). Bursting pressures of groups were unaffected by the treatment. Tissue antioxidant levels of groups were affected by the treatment. Morbidity and mortality were similar in all groups.

CONCLUSIONS

The present study demonstrated that a single intraperitoneal instillation of lornoxicam in buffer solution at the end of the surgery reduces adhesion formation in rats bacterial peritonitis model. It was also determined that lornoxicam had no negative effect on the healing of intestinal anastomosis, abscess and anastomotic leakage. Use of lornoxicam in peritonitis was effective in decreasing the oxidative stress of tissue during peritonitis.