Effect of transforming growth factor beta on postoperative adhesion formation and intact peritoneum

Carbon monoxide (CO) derived from the CO-releasing molecule CORM-2 reduces peritoneal adhesion formation in a rat model

BACKGROUND

Although low-dose carbon monoxide (CO) administration has been shown to have an anti-fibrotic effect in various fibrotic diseases, its effects on peritoneal adhesion (PA), one of the postoperative complications, are not elucidated. In this study, the effect of CO-releasing tricarbonyldichlororuthenium (II) dimer (CORM-2) administration on the formation of PA and the underlying factors of its potential effect were investigated.

METHODS AND RESULTS

After the induction of PA, rats were divided into four groups with 8 rats in each group. The rats received either (i) dimethyl sulfoxide:saline solution (1:10) as a vehicle, (ii) 2.5 mg/kg CORM-2, (iii) 5 mg/kg CORM-2, or (iv) inactive (i) CORM (iCORM) intragastrically every day for a duration of 7 days. PA was not induced in rats (n = 8) designated as sham controls. Gross, histological, immunohistochemical and quantitative real-time polymerase chain reaction analyses were performed to evaluate the effectiveness of CORM-2 administration. Gross analysis showed that CORM-2 administration reduced PA formation compared to rats treated with vehicle. Histological and immunohistochemical examinations showed that increased collagen deposition, myofibroblast accumulation, microvessel density, and M1 macrophage count in the peritoneal fibrosis area of vehicle-treated rats decreased following CORM-2 treatments. PCR analyses showed that CORM-2 treatments decreased hypoxia-induced Hif1a, profibrotic Tgfb1, ECM components Col1a1 and Col3a1, collagen degradation suppressor Timp1, fibrinolysis inhibitor Serpine1, and pro-inflammatory Tnf mRNA expressions, while increasing the M2 macrophage marker Arg1 mRNA expression.

CONCLUSIONS

These results suggested that CORM-2 administration reduces PA formation by affecting adhesiogenic processes such as pro-inflammatory response, fibrinolytic system, angiogenesis and fibrogenesis.

Prevention strategies of postoperative adhesion in soft tissues by applying biomaterials: Based on the mechanisms of occurrence and development of adhesions

Postoperative adhesion (POA) widely occurs in soft tissues and usually leads to chronic pain, dysfunction of adjacent organs and some acute complications, seriously reducing patients' quality of life and even being life-threatening. Except for adhesiolysis, there are few effective methods to release existing adhesion. However, it requires a second operation and inpatient care and usually triggers recurrent adhesion in a great incidence. Hence, preventing POA formation has been regarded as the most effective clinical strategy. Biomaterials have attracted great attention in preventing POA because they can act as both barriers and drug carriers. Nevertheless, even though much reported research has been demonstrated their efficacy on POA inhibition to a certain extent, thoroughly preventing POA formation is still challenging. Meanwhile, most biomaterials for POA prevention were designed based on limited experiences, not a solid theoretical basis, showing blindness. Hence, we aimed to provide guidance for designing anti-adhesion materials applied in different soft tissues based on the mechanisms of POA occurrence and development. We first classified the postoperative adhesions into four categories according to the different components of diverse adhesion tissues, and named them as "membranous adhesion", "vascular adhesion", "adhesive adhesion" and "scarred adhesion", respectively. Then, the process of the occurrence and development of POA were analyzed, and the main influencing factors in different stages were clarified. Further, we proposed seven strategies for POA prevention by using biomaterials according to these influencing factors. Meanwhile, the relevant practices were summarized according to the corresponding strategies and the future perspectives were analyzed.

HPLC/MS characterization of Syzygium aromaticum L. and evaluation of its effects on peritoneal adhesion: Investigating the role of inflammatory cytokines, oxidative factors, and fibrosis and angiogenesis biomarkers

The dried flower bud of Syzygium aromaticum L. (S. aromaticum) (Myrtaceae), cloves, have been used for their analgesic and anti-inflammatory activities. Peritoneal adhesion (PA) is the most common complication of abdominal and pelvic surgeries, which causes significant adverse effects and severe economic burden. The present study aimed to evaluate the preventive effect of S. extract (SAE) on PA formation in a rat model. Male Wistar 8-week-old rats were randomly divided into sham, control (received vehicle), and treatment (0.25%, 0.5%, and 1% w/v of SAE) groups. The adhesion and related factors were examined using the Nair scoring system and immunological and biochemical kits for the levels of inflammatory cytokines [interleukin (IL)-6 and tumor necrosis factor (TNF)-α], growth factors [transforming growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF)], oxidative [nitric oxide (NO) and malondialdehyde (MDA)], and anti-oxidative [glutathione (GSH)] factors. Our results figured out that the adhesion score and IL-6, TNF-α, TGF-β1, VEGF, NO, and MDA levels were significantly increased, but the GSH level was decreased in the control group compared to the sham group (p < 0.001-0.05). On the other hand, the 0.25% SAE group had a lower adhesion score, and IL-6, TNF-α, TGF-β1, VEGF, NO, and MDA levels were significantly decreased compared with the vehicle group, and the level of GSH was increased (p < 0.001-0.05). SAE could efficiently reduce adhesion score and regulate inflammatory cytokines, oxidative and anti-oxidative factors, and biomarkers of fibrosis and angiogenesis. Therefore, clove extract can be considered a potential candidate for PA management.

Prevention of post-surgical adhesion bands by local administration of frankincense n-hexane extract

Background

and purpose: The formation of postoperative intra-abdominal adhesion band formation may lead to severe complications. This study aimed to evaluate the preventive effect of local administration of frankincense n-hexane extract (FHE) on the formation of postsurgical adhesion bands.

Materials and methods

FHE was extracted from the resin of a Boswellia sacra tree and its components were identified by gas chromatography-mass spectrometry (GC-MS). In an animal model, the expression levels of TNF-α and TGF-β1 cytokines after application of FHE were assessed to check the inflammatory and fibrotic cues, respectively.

Results

Following FHE compound analysis, in vivo experiments demonstrated that intraoperative local administration of FHE resulted in the prevention of adhesion band formation. The adhesion grades in the FHE-treated group were significantly lower than those in the negative control (NC) and the positive control (Interceed). The infiltration of inflammatory cells observed by histopathology revealed a significant anti-inflammatory potential of FHE. Furthermore, the gene expression results proved that significant suppression of TNF-α and TGF-β1 was responsible for its antiadhesion properties.

Conclusions

The study reported the potential of FHE as an ointment for the prevention of adhesion bands.

•

Recognition of compounds with anti-inflammatory, antifibrotic activities in FHE using gas chromatography-mass spectrometry.

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The avoidance of adhesion bands formation, in vivo following intraoperative local administration of FHE.

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A notable anti-inflammatory potential of FHE detected by histopathology results.

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Approving the regulation of TNF-α and TGF-β1 involved in the intra-abdomen adhesion preventive properties of FHE.

Post-Operative Adhesions: A Comprehensive Review of Mechanisms

Post-surgical adhesions are common in almost all surgical areas and are associated with significant rates of morbidity, mortality, and increased healthcare costs, especially when a patient requires repeat operative interventions. Many groups have studied the mechanisms driving post-surgical adhesion formation. Despite continued advancements, we are yet to identify a prevailing mechanism. It is highly likely that post-operative adhesions have a multifactorial etiology. This complex pathophysiology, coupled with our incomplete understanding of the underlying pathways, has resulted in therapeutic options that have failed to demonstrate safety and efficacy on a consistent basis. The translation of findings from basic and preclinical research into robust clinical trials has also remained elusive. Herein, we present and contextualize the latest findings surrounding mechanisms that have been implicated in post-surgical adhesion formation.

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.

A review: progress in preventing tissue adhesions from a biomaterial perspective

Postoperative adhesions (POA) are one of the main problems suffered by patients and are a common complaint. It is considered to be closely associated with the healing mechanism of damaged tissues. Tissue adhesions accompany other symptoms such as inflammation, pain, and even dyskinesia under certain conditions, compromising the patients' quality of life. On the other hand, common treatments involve high costs, re-surgery or long-term hospital stays. Therefore, alternative approaches need to be formulated so that aforementioned problems can be resolved. To this end, a review of recent advances in this context is imperative. In this review, we have highlighted the mechanism of adhesion formation, advances in common therapeutic approaches, and prospective treatments in preventing tissue adhesions. Based on the literature, it can be determined that the disadvantages of available commercial products in the treatment of tissue adhesion have led researchers to utilize alternative methods for designing anti-adhesive products with different structures such as electrospun fibrous mats, hydrogels, and nanospheres. These studies are on the fast track in producing optimal anti-adhesion materials. We hope that this article can attract attention by showing various mechanisms and solutions involved in adhesion problems and inspire the further development of anti-adhesion biomaterials.

The in vivo anti-fibrotic function of calcium sensitive receptor (CaSR) modulating poly(p-dioxanone-co-l-phenylalanine) prodrug

In present study, the apoptosis induction and proliferation suppression effects of l-phenylalanine (l-Phe) on fibroblasts were confirmed. The action sites of l-Phe on fibroblasts suppression were deduced to be calcium sensitive receptor (CaSR) which could cause the release of endoplasmic reticulum (ER) Ca²⁺ stores; disruption of intracellular Ca²⁺ homeostasis triggers cell apoptosis via the ER or mitochondrial pathways. The down-regulation of CaSR were observed after the application of l-Phe, and the results those l-Phe triggered the increasing of intracellular Ca²⁺ concentration and calcineurin expression, and then the apoptosis and increasing G1 fraction of fibroblasts have verified our deduction. Hence, l-Phe could be seen as a kind of anti-fibrotic drugs for the crucial participation of fibroblast in the occurrence of fibrosis. And then, poly(p-dioxanone-co-l-phenylalanine) (PDPA) which could prolong the in-vivo anti-fibrotic effect of l-Phe for the sustained release of l-Phe during its degradation could be treated as anti-fibrotic polymer prodrugs. Based on the above, the in vivo anti-fibrotic function of PDPA was evaluated in rabbit ear scarring, rat peritoneum lipopolysaccharide, and rat sidewall defect/cecum abrasion models. PDPA reduced skin scarring and suppressed peritoneal fibrosis and post operation adhesion as well as secretion of transforming growth factor-β1 in injured tissue. These results indicate that PDPA is an effective agent for preventing fibrosis following tissue injury.

STATEMENT OF SIGNIFICANCE

We have previously demonstrated that poly(p-dioxanone-co-l-phenylalanine) (PDPA) could induce apoptosis to fibroblast and deduced that the inhibitory effect comes from l-phenylalanine. In present study, the inhibition mechanism of l-phenylalanine on fibroblast proliferation was demonstrated. The calcium sensitive receptor (CaSR) was found to be the action site. The CaSR was downregulated after the application of l-phenylalanine, and then the ER Ca²⁺ stores were released. The released Ca²⁺ can simultaneously activate Ca²⁺/calcineurin and then trigger apoptosis and G1 arrest of fibroblast. Hence, l-phenylalanine could be seen as anti-fibrosis drug and PDPA which conjugate l-phenylalanine by hydrolytic covalent bonds could be seen as l-phenylalanine polymer prodrug. Based above, the in vivo anti-fibrotic function of PDPA were verified in three different animal models.

A Time Course of Bevacizumab (Anti-VEGF) Effect on Rat Peritoneum: Relations Between Antiadhesive Action and Fibrin Regulation Enzymes

BACKGROUND

To investigate the early and late antiadhesive effect and any changes of fibrin matrix regulation enzymes on rat peritoneum, after local administration of bevacizumab.

METHODS

Rats were subjected to cecal abrasion. Bevacizumab (5 mg/kg) against placebo was given intraperitoneally. On the 2nd, 14th, and 28th postoperative days adhesions were scored, and tissue plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), matrix metalloproteinase-9 (MMP-9), degree of fibrosis, and angiogenesis were measured in abrased cecum and in intact parietal peritoneum.

RESULTS

Bevacizumab significantly reduced adhesions up to 15% on the 2nd, 52.5% on the 14th, and 55% on the 28th postoperative day, and significantly increased tPA concentrations in peritoneum. PAI-1 was decreased, and a significantly higher tPA/PAI-1 ratio along with an increase of MMP-9 was measured at all time points. Fibrosis and angiogenesis were significantly lower on the 14th and 28th postoperative days.

CONCLUSIONS

Local bevacizumab administration has a strong early and late antiadhesive action on rat peritoneum, mediated by changes in the tPA/PAI-1 and MMP balance in favor of fibrinolysis up to 28 days after operations.

Efficacy of simvastatin in reducing postoperative adhesions after thyroidectomy: an experimental study

BACKGROUND

We aimed to investigate whether simvastatin had any impact on the prevention of adhesion formation after thyroidectomy in a rat model.

METHODS

This study was performed in 66 Wistar albino rats randomized into three experimental groups. A right hemithyroidectomy was carried out in all the rats. Simvastatin was administered locally at a dose of 0.5 mg/kg and 0.8 mg/kg. Control rats received a saline solution only. Changes during the 1st week, 1st month and 3rd month were evaluated. Efficacy of the treatment was assessed by using a scoring system.

RESULTS

The severity of adhesions in low-dose simvastatin group was significantly less than the control and high-dose groups during the 1st and 3rd month (p < .05). In addition, adhesions were less in the high dose group during the 3rd month, when compared to the control group (p < .05). Moreover, fibrosis and fibroblast scores, which represent adhesions, were significantly lower in low-dose and high-dose groups at 3rd month, compared to controls (p < .05).

CONCLUSIONS

We investigated the influence of simvastatin application on post-thyroidectomy adhesion formation in rats. Whether adhesions, causing technical difficulties during neck redo surgery, can be reduced by the use of simvastatin in human, needs to be studied.

Periostin antisense oligonucleotide prevents adhesion formation after surgery in mice

To study the role of periostin in adhesion formation, the effect of periostin antisense oligonucleotide (PAO) on adhesion formation was evaluated in mice. Under anesthesia, the serous membrane of the cecum was abraded, and the adhesion score and mRNA levels of periostin and its related factors were determined after surgery. Saline, 40 mg/kg of negative sense oligonucleotide (NSO), or 40 mg/kg of PAO were injected into the abdomen after surgery, and the adhesion score and mRNA levels were evaluated 14 days later. Filmy adhesion formation was observed 1 day after surgery, and the adhesion score increased gradually to 14 days. The mRNA levels of periostin, transforming growth factor (TGF)-β, and collagen I increased gradually from 3 days to 14 days. The adhesion score of PAO was significantly lower than of saline or NSO 14 days after surgery. The mRNA levels of periostin, TGF-β, and collagen I were also significantly attenuated by treatment with PAO compared with saline or NSO. Thus, these results demonstrated that the periostin mRNA level increased in the abraded cecum, and PAO prevented adhesion formation along with attenuation of the periostin mRNA level.

Pirfenidone vs. sodium hyaluronate/carboxymethylcellulose as prevention of the formation of intra-abdominal adhesions after colonic surgery. A randomized study in an experimental model

INTRODUCTION

Up to 93% of patients undergoing abdominal surgery will develop intra-abdominal adhesions with the subsequent morbidity that they represent. Various substances have been tested for the prevention of adhesions with controversial results; the aim of our study is to compare the capability of pirfenidone in adhesion prevention against sodium hyaluronate/carboxymethylcellulose.

METHODS

A randomized, prospective, longitudinal experimental study with Winstar rats. They were divided into 3 groups. The subjects underwent an exploratory laparotomy and they had a 4cm(2) cecal abrasion. The first group received saline on the cecal abrasion, and groups 2 and 3 received pirfenidone and sodium hyaluronate/carboxymethylcellulose respectively. All rats were sacrificed on the 21st day after surgery and the presence of adhesions was evaluated with the modified Granat scale. Simple frequency, central tendency and dispersion measures were recorded. For the statistical analysis we used Fisher's test.

RESULTS

To evaluate adhesions we used the Granat's modified scale. The control group had a median adhesion formation of 3 (range 0-4). The pirfenidone group had 1.5 (range 0-3), and the sodium hyaluronate/carboxymethylcellulose group had 0 (range 0-1). There was a statistically significant difference to favor sodium hyaluronate/carboxymethylcellulose against saline and pirfenidone (P<0.009 and P<.022 respectively).

CONCLUSIONS

The use of sodium hyaluronate/carboxymethylcellulose is effective for the prevention of intra-abdominal adhesions. More experimental studies are needed in search for the optimal adhesion prevention drug.

[Intestinal obstruction secondary to postoperative adhesion formation in abdominal surgery. Review]

The development of intestinal obstruction after upper and lower abdominal surgery is part of the daily life of each every surgeon. Despite this, there are very few good quality studies that allow enable assessment of the frequency of intestinal obstruction to be assessed, even although postoperative adhesions are the cause of considerable direct and indirect morbidity and its prevention can be considered a public health problem. And yet, in Mexico, at this time, there is no validated recommendation validated on the prevention of adhesions, or more particularly, in connection with the use of a variety of anti-adhesion commercial products which have been marketed for at least a decade. Intraperitoneal adhesions develop between surfaces without peritoneum of the abdominal organs, mesentery, and abdominal wall. The most common site of adhesions is between the greater omentum and anterior abdominal wall previous. Despite the frequency of adhesions and their direct and indirect consequences, just there is only one published a recommendation (from gynaecological literature), regarding peritoneal adhesion prevention. As regards of colorectal surgery, performed more than 250,000 colorectal resections are performed annually in the United States, and from 24% to 35% of them will develop a complication. The clinical and economic financial burden of these complications is enormous, and surgeries colorectal surgery been specifically highlighted as a potential point prevention point of surgical morbidity.

Cell-based therapy for preventing postoperative adhesion and promoting regeneration after hepatectomy

Postoperative adhesion is a critical clinical issue after almost all abdominal or pelvic surgeries including liver surgery. Postoperative adhesion causes several complications, such as small bowel obstruction and chronic abdominal pain. Furthermore, it makes reoperation much more difficult, leading to increased mortality and morbidity rate. Postoperative adhesion is particularly problematic for repeated hepatectomy, since hepatic malignant neoplasm recurs frequently and repeated hepatectomy is widely used as one of the most curative treatments. Several treatments to reduce postoperative adhesion have been developed, which include laparoscopic surgery, administration of pharmacological agents and use of prophylactic barrier materials. However, none of them are optimal. We have proposed a novel treatment using a cell sheet of fetal liver mesothelial cells (FL-MCs) to prevent postoperative adhesion in a novel mouse model. Besides adhesion, repeated hepatectomy has another serious problem; although the liver has a remarkable ability to regenerate, the recovery of liver mass and function of the remnant liver after multiple repeated hepatectomy is limited. The FL-MC cell sheet enhances proliferation of hepatocytes after hepatectomy by providing growth factors for hepatocytes. Thus the FL-MC sheet could simultaneously solve the two problems associated with repeated hepatectomy.

Encapsulating peritoneal sclerosis-a rare but devastating peritoneal disease

Encapsulating peritoneal sclerosis (EPS) is a devastating but, fortunately, rare complication of long-term peritoneal dialysis. The disease is associated with extensive thickening and fibrosis of the peritoneum resulting in the formation of a fibrous cocoon encapsulating the bowel leading to intestinal obstruction. The incidence of EPS ranges between 0.7 and 3.3% and increases with duration of peritoneal dialysis therapy. Dialysis fluid is hyperosmotic, hyperglycemic, and acidic causing chronic injury and inflammation in the peritoneum with loss of mesothelium and extensive tissue fibrosis. The pathogenesis of EPS, however, still remains uncertain, although a widely accepted hypothesis is the "two-hit theory," where, the first hit is chronic peritoneal membrane injury from long standing peritoneal dialysis followed by a second hit such as an episode of peritonitis, genetic predisposition and/or acute cessation of peritoneal dialysis, leading to EPS. Recently, EPS has been reported in patients shortly after transplantation suggesting that this procedure may also act as a possible second insult. The process of epithelial-mesenchymal transition of mesothelial cells is proposed to play a central role in the development of peritoneal sclerosis, a common characteristic of patients on dialysis, however, its importance in EPS is less clear. There is no established treatment for EPS although evidence from small case studies suggests that corticosteroids and tamoxifen may be beneficial. Nutritional support is essential and surgical intervention (peritonectomy and enterolysis) is recommended in later stages to relieve bowel obstruction.

TGF-β1 promotes transition of mesothelial cells into fibroblast phenotype in response to peritoneal injury in a cell culture model

BACKGROUND

Peritoneal adhesions are a clinical problem. A key to the understanding of peritoneal adhesions is to study the healing of mesothelial cells within the peritoneal cavity following surgery. Transforming growth factor beta (TGF-βs) affects this healing process. The aim of this study was to investigate the effects of different concentrations of TGF-β1 on the healing rate and healing properties of mesothelial cells.

MATERIALS AND METHODS

Human mesothelial cells from peritoneal fluid were collected, cultured and a mechanical wound was created. The restoration of the mesothelial surface with and without increasing concentrations of TGF-β1 was monitored.

RESULTS

The denuded area was restored within 24 h. The healing rate was most extensive between the first and second hour after the damage (61.9 ± 22.8 μm/h). No significant difference in healing rate were observed when increasing levels of TGF-β1 were used. However, higher concentrations of TGF-β1 increased cell size and the cells presented more fibroblast specific properties. Lower TGF-β1 concentrations increased the number of proliferating cells.

CONCLUSIONS

This study indicates the importance of high levels TGF-β1 in mesothelial cell healing, mainly by changing the actual healing properties of the cells. Elevated levels of TGF-β1 might promote mesothelial cell transition towards a more fibroblast-like appearance.

A new TGF-β3 controlled-released chitosan scaffold for tissue engineering synovial sheath

The post-operative outcome of flexor tendon healing remains limited by flexor tendon adhesion that reduces joint range of motion. Despite improvement in different methods, peritendinous adhesion formation continues to present a formidable challenge. Recent studies showed that transforming growth factor-β3 (TGF-β3) may be the key factor to reducing adhesion formation in skin or tendon. In this study, we designed a novel type of tissue engineering synovial sheath containing TGF-β3, to prevent flexor tendon adhesion. First, to achieve a stable release of TGF-β3, chitosan microspheres, prepared by crosslinking-emulsion, were used for the delivery of TGF-β3. Second, a three-dimensional chitosan scaffold was prepared by lyophilization, and TGF-β3 microspheres were carefully introduced into the scaffold. Then, synovial cells were cultured and then seeded into the TGF-β3 loaded scaffold to produce TGF-β3 controlled-released tissue engineering synovial sheath. Tests clearly demonstrated that the scaffold has good structure and compatibility with cells. These results expand the feasibility of combinative strategies of controlled protein release and tissue-engineered synovial sheath formation. Application of this scaffold to tendon repair sites may help to prevent adhesion of tendon healing.

Medical ozone therapy decreases postoperative uterine adhesion formation in rats

PURPOSE

Various studies have been performed to find out novel treatment strategies to prevent postoperative adhesion formation. Ozone therapy (OT) is shown to reduce inflammation in several pathological conditions. Therefore, we aimed to evaluate the efficacy of OT in a rat model of experimental uterine adhesion (EUA).

METHODS

Thirty female Wistar rats (200-250 g) were divided into three groups: sham, EUA and EUA+OT. EUA and EUA+OT groups were subjected to the postoperative adhesion procedure by bipolar coagulation on the uterine horns and corresponding pelvic sidewall parietal peritoneum. EUA+OT group received 0.7 mg/kg daily single dose for 3 days of ozone/oxygen mixture intraperitoneally after adhesion induction. All animals were killed on the 7th day and uterine adhesions were scored. Uterine tissues and peritoneal washing fluid were harvested for all analyses.

RESULTS

Uterine malondialdehyde levels in the EUA group were significantly higher compared to the other groups. However, in the EUA group, uterine superoxide dismutase and glutathione peroxidase activities were lower than in other groups. Peritoneal fluid TNF-α levels were found to be significantly different for all groups (p < 0.001). Macroscopic total adhesion score was significantly higher in the EUA group compared to the other groups (p < 0.001). But, total score in the EUA+OT group was lower than in the EUA group (p = 0.006).

CONCLUSIONS

Medical OT prevents postoperative uterine adhesions by modulating TNF-α levels and oxidative/antioxidative status in an experimental uterine adhesion model.

Prevention of peritoneal adhesions: a promising role for gene therapy

Adhesions are the most frequent complication of abdominopelvic surgery, yet the extent of the problem, and its serious consequences, has not been adequately recognized. Adhesions evolved as a life-saving mechanism to limit the spread of intraperitoneal inflammatory conditions. Three different pathophysiological mechanisms can independently trigger adhesion formation. Mesothelial cell injury and loss during operations, tissue hypoxia and inflammation each promotes adhesion formation separately, and potentiate the effect of each other. Studies have repeatedly demonstrated that interruption of a single pathway does not completely prevent adhesion formation. This review summarizes the pathogenesis of adhesion formation and the results of single gene therapy interventions. It explores the promising role of combinatorial gene therapy and vector modifications for the prevention of adhesion formation in order to stimulate new ideas and encourage rapid advancements in this field.

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.

Applying amphibian limb regeneration to human wound healing: a review

In contrast to the limited regenerative ability found in human wound healing, which often results in unsatisfying and deficient scar formation, urodele amphibians, with the Mexican axolotl as a prime example, expose an extraordinary regenerative capacity. This regeneration leads to a perfect restoration of tissue architecture, function, and aesthetics with the axolotl being actually able to reclaim complete limbs. Evolutionary considerations suggest that regeneration might be a biologic principle which also underlies human wound healing. Experimental findings, such as comparative studies on transforming growth factor-β and fibroblast growth factor accentuate this assumption. Regeneration, as recent data indicate, might be a question of adaptive immunity. The loss of regenerative potency correlates with the decrease of regeneration in most species, whereas the Mexican axolotl lacks adaptive immunity throughout its life. The characterization of molecular pathways as a prerequisite for any control of regenerative processes sets an increasing indication toward the transfer into human beings. Some regenerative techniques, eg, recombinant transforming growth factor-β have already emerged. Molecular findings suggest that there is an intrinsic regenerative capacity in humans which might be initiated under appropriate circumstances. The Mexican axolotl is liable to diverse surgical and molecular approaches. Though well-known among developmental biologists, its exploitation for experimental Plastic Surgery still has to be established. We therefore intend to give an introduction to amphibian regeneration and the common evolutionary roots of regeneration and human wound healing, as we believe that Plastic Surgery takes a unique advantage of performing basic research on amphibian regeneration.

Prevention of postoperative peritoneal adhesions: a review of the literature

BACKGROUND

postoperative adhesions are a significant health problem with major implications on quality of life and health care expenses. The purpose of this review was to investigate the efficacy of preventative techniques and adhesion barriers and identify those patients who are most likely to benefit from these strategies.

METHODS

the National Library of Medicine, Medline, Embase, and Cochrane databases were used to identify articles related to postoperative adhesions.

RESULTS

ileal pouch-anal anastomosis, open colectomy, and open gynecologic procedures are associated with the highest risk of adhesive small-bowel obstruction (class I evidence). Based on expert opinion (class III evidence) intraoperative preventative principles, such as meticulous hemostasis, avoiding excessive tissue dissection and ischemia, and reducing remaining surgical material have been published. Laparoscopic techniques, with the exception of appendicitis, result in fewer adhesions than open techniques (class I evidence). Available bioabsorbable barriers, such as hyaluronic acid/carboxymethylcellulose and icodextrin 4% solution, have been shown to reduce adhesions (class I evidence).

CONCLUSIONS

postoperative adhesions are a significant health problem with major implications on quality of life and health care. General intraoperative preventative techniques, laparoscopic techniques, and the use of bioabsorbable mechanical barriers in the appropriate cases reduce the incidence and severity of peritoneal adhesions.

Peritoneal adhesions in human and veterinary medicine: from pathogenesis to therapy. A review

Any peritoneal inflammatory process consequent to infections or surgical injuries may induce abdominal adhesion formation. Peritoneal adhesions are connective laciniae that develop among abdomino-pelvic organs that limit physiologic visceral motion. Consequently, fertility may be impaired, and intestinal obstruction and pelvic pain may develop, mainly in subjects that had undergone gynaecological surgery. This review illustrates the pathogenic steps of adhesiogenesis and the therapeutic scenario that evolved over the years to tackle the threat of peritoneal adhesions, both in domestic animals and in women.

Correlation between overexpression of transforming growth factor-beta 1 in occluded fallopian tubes and postsurgical pregnancy among infertile women

OBJECTIVE

To compare the expression profiles of transforming growth factor-beta 1 (TGF-β1) and its receptors in occluded tubes of infertile women with those of control patients and to evaluate the potential correlation with postsurgical pregnancy outcome.

METHODS

The expression profiles of TGF-β1, TGF-β1R1, and TGF-β1R2 in occluded fallopian tubes were compared using immunohistochemistry between 60 infertile patients with adhered tubes and 60 control patients with normal tubes; potential correlations with postsurgical fertility were evaluated at 2-year follow up.

RESULTS

Immunostainings of TGF-β1, TGF-β1R1, and TGF-β1R2 were all significantly elevated in patients with adhered tubes compared with normal specimens (P<0.001). In adhered specimens, correlation analyses showed positive correlations between TGF-β1 and TGF-β1R1 (P=0.008), and TGF-β1 and TGF-β1R2 (P=0.035). At 2-year follow up, 32 of the 60 infertile women had achieved normal pregnancies, 5 had had ectopic pregnancies, and 23 remained infertile. Correlation analysis showed that TGF-β1 expression level was negatively correlated with pregnancy outcome (r=-0.445, P<0.001), independent of adhesion severity or patient age.

CONCLUSION

TGF-β1 expression was independently correlated with the postsurgical pregnancy outcome among infertile women.

Temporal and spatial expression of TGF-beta1 in an Achilles tendon section model after application of platelet-rich plasma

BACKGROUND

To investigate the effect of platelet-rich plasma (PRP) on TGF-beta1 expression during tendon healing.

METHODS

We used 48 skeletally mature New Zealand White rabbits. 24 rabbits received the PRP, and 24 rabbits served as an untreated control group. Equal numbers of animals were sacrificed at 1st, 2nd, 3rd, and 4th week. The surgical procedure involved a transverse incision to transect the Achilles tendon. A volume of 1ml of PRP was then injected into the tendon mass in the PRP group. Histological and immunohistochemical evaluations with an anti-TGF-beta primary antibody were performed.

RESULTS

The pattern of expression of TGF-beta1 in the PRP group was characterized by a significant upregulation during the first 2 weeks and subsequently significant downregulation in the 3rd and 4th week in comparison with the controls.

CONCLUSIONS

Our results suggest that PRP may affect the tendon healing process by altering the expression of TGF-beta1.

Peritoneal adhesion formation and reformation tracked by sequential laparoscopy: optimizing the time point for adhesiolysis

BACKGROUND

In a high proportion of patients, operatively lysed adhesions reform. Using a rabbit adhesiogenesis model, this study assessed the efficacy of adhesiolysis and examined how this relates to the tissue composition of adhesions at the time of lysis.

METHODS

Polypropylene meshes (5 x 3.5 cm) were implanted on the parietal peritoneum of New Zealand white rabbits. Some animals were killed 3, 7, 14, and 90 days postimplantation to obtain adhesion tissue. Adhesion formation/reformation was monitored by sequential laparoscopy in other animals kept for 90 days and in a separate experimental group subjected to adhesiolysis at 3 days postimplantation. Immune and inflammatory response markers were determined by immunohistochemical, Western blotting, and real-time reverse transcriptase polymerase chain reaction procedures in adhesion tissue; areas occupied by adhesions were quantified in meshes.

RESULTS

In animals undergoing adhesiolysis, mesh areas covered by adhesions were significantly decreased at each follow-up time and affected areas became mesothelialized. Increased transforming growth factor (TGF)-beta1 expression was detected in adhesions at 3 days. Greatest TGF-beta1 and vascular endothelial growth factor (VEGF) protein expressions were observed at 7 days, whereas genetic overexpression was noted at 14 days. Active inflammatory cells peaked at the 7-day time point.

CONCLUSION

Adhesions formed at 3 days; at this critical time, an adhesiolysis was effective in preventing reformation of future adhesions. TGF-beta1 gene and protein expression were increased in 3-day adhesions with respect to the omentum. Levels of active TGF-beta1 and VEGF were increased at 7 days, along with the inflammatory response at this time point related to tissue remodeling, which led to stabilization of adhesions.

Non-viral Smad7 gene delivery and attenuation of postoperative peritoneal adhesion in an experimental model

BACKGROUND

Postoperative intra-abdominal adhesion is associated with high morbidity and mortality. Smad7, a protein that occupies a strategic position in fibrogenesis, inhibits the transforming growth factor (TGF) beta/Smad signalling pathway. In this study the therapeutic potential of exogenous Smad7 in preventing fibrogenesis in postoperative intra-abdominal adhesion was investigated.

METHODS

Intra-abdominal adhesion was induced in a rodent model by peritoneal abrasion. Smad7 was delivered into the peritoneal cavity by a non-viral ultrasound-microbubble-mediated naked gene transfection system. The effect of Smad7 transgene on adhesion formation was studied by measuring changes in TGF-beta, fibrogenic factors, alpha-SMA and Smad2/3 activation in the anterior abdominal wall.

RESULTS

Four weeks after surgical abrasion, all rats developed significant peritoneal adhesion with enhanced TGF-beta expression, increased levels of extracellular matrix components and activated myofibroblasts, accompanied by decreased Smad7 expression and increased Smad2/3 activation. In rats treated with the Smad7 transgene, the incidence and severity of peritoneal adhesion were significantly reduced, with biochemical downregulation of fibrogenic factors and inhibition of Smad2/3 activation. Serial quantitation using magnetic resonance imaging revealed a significant reduction in adhesion areas from day 14 onwards.

CONCLUSION

Ultrasound-microbubble-mediated gene transfection provides timely targeted gene delivery for the treatment of postoperative peritoneal adhesions.

Cytokine orchestration in post-operative peritoneal adhesion formation

Peritoneal adhesions are a near inevitable occurrence after laparotomy and a major cause of both patient and physician misery. To date, clinical attempts at their amelioration have concentrated on manipulating the physical factors that affect their development despite a wealth of experimental data elucidating the molecular mechanisms that underlie their initiation, development and maturation. However, the advent of targeted, specific anti-cytokine agents as directed therapy for inflammatory and neoplastic conditions raises the prospect of a new era for anti-adhesion strategies. To harness this potential will require considerable cross-disciplinary collaboration and that surgeon-scientists propel themselves to the forefront of this emerging field.

Biology of the peritoneum in normal homeostasis and after surgical trauma

The peritoneum is a serous membrane, which has a protective function for the contents of the abdominal cavity. It maintains homeostasis by allowing exchange of molecules and production of peritoneal fluid, thus providing an environment in which intra-abdominal organs can function properly. When traumatized, whether by surgery or due to inflammatory processes, a series of responses come into action to regenerate the injured part of the peritoneum. The inflammatory reaction causes influx of inflammatory cells but also activates resident mesothelial cells, ultimately leading to a fibrinous exudate. Depending on the severity of the trauma this exudate is transient due to fibrinolysis, or becomes more dense as a result of fibroblasts persisting, leading to fibrinous adhesions. A pivotal role is taken by the enzyme plasmin and its promotors and inhibitors; it is mainly the tissue-type plasminogen activator/plasminogen activator inhibitor ratio which determines the rate of fibrinolysis and therefore the rate of adhesion formation. The rate of injury determines the rate and extent of the inflammatory response to that injury; in its turn the inflammatory reaction determines the extent of adhesion formation. One should realize this when performing intra-abdominal surgery, which is in fact operating inside the peritoneal organ.

The effect of immunosuppression on peritoneal adhesions formation after small bowel transplantation in rats

BACKGROUND

The reported incidence of adhesion related small bowel obstruction after abdominal organ transplantation is considerably lower than other abdominal procedures. The purpose of the study was to investigate the influence of immunosuppression on peritoneal adhesion formation after intestinal transplantation in rats.

METHODS

Four groups of rats (n = 6) underwent small bowel intestinal transplantation in syngeneic (Groups A, B) and allogeneic (Groups C, D) combinations. Groups B and D received tacrolimus immunosuppression 1 mg/kg/d. Animals were euthanized on postoperative day 7, and the total adhesion score (TAS), tissue hydroxyproline content (HPC), TGF-beta mRNA expression levels and histology were examined.

RESULTS

All of the animals in Group C showed severe histological (Grade III) acute cellular rejection. There were no histological signs of rejection in Group D. A significant reduction in TAS was observed in tacrolimus treated animals in both syngeneic and allogeneic combinations (Groups B and D), compared with controls (Groups A and C) (P < 0.001 and P < 0.01, respectively). TAS results correlated with the differences in TGF-beta levels that showed significant reduction when each immunosuppressed group was compared with its nontreated counterpart, i.e., (Groups B versus A, P < 0.05, and Groups D versus C, P < 0.01). TGF-beta levels were significantly high in the rejection group (C) and correlated with the intense adhesion formation that was demonstrated in that group. Group C was also the only group in which a significant elevation in HPC was demonstrated (P < 0.001).

CONCLUSION

Intense adhesion formation occurs during early posttransplant acute rejection. Postsurgical adhesion formation is significantly reduced in immunosuppressed rats after intestinal transplantation.

Impact of aromatase inhibitors on adhesion formation in a rat model

OBJECTIVE

To investigate the antiadhesion potential of tamoxifen and anastrozole in a rat uterine horn model.

DESIGN

Experimental animal study.

SETTING

University animal laboratory.

ANIMAL(S)

Forty-five female Wistar albino rats.

INTERVENTION(S)

We examined the effects of tamoxifen and anastrozole to reduce the extent and severity of postoperative adhesions in a rat uterine horn model: the control group received no therapy while the second and third groups received 500 mug/day tamoxifen and 0.2 mg/kg/day anastrazole, respectively, through an enteric tube, starting 5 days before surgery. These protocols were continued for 14 days after the surgery until the rats were killed.

MAIN OUTCOME MEASURE(S)

Adhesions were scored according to their extent and severity, and specimens were also evaluated and scored histologically according to the following features: inflammation, fibroblastic activities, foreign body reaction, collagen formation, and vascular proliferation.

RESULT(S)

Anastrozole had the lowest mean adhesion scores, and these scores were significantly different from those of the controls. However, there were no statistically significant differences between control and tamoxifen groups and between tamoxifen and anastrozole groups. Histologic scores were lowest in the anastrozole group, which were statistically different from those of the tamoxifen and anastrozole groups, whereas scores of the control group were not statistically different from those of the tamoxifen group.

CONCLUSION(S)

Anastrazole decreased postsurgical adhesion scores by both visual scores and histologic analyses in a rat model. Further experimental and clinical trials are required to confirm these results.

The effect of antibodies to TGF-beta1 and TGF-beta2 at a site of sciatic nerve repair

Scar formation at a site of nerve injury can cause a mechanical barrier to axonal regeneration and lead to the development of multiple axonal sprouts to form a neuroma. We have investigated the hypothesis that the application of a scar-preventing agent to a nerve repair site would enhance regeneration of the nerve and reduce neuroma formation. The left sciatic nerve was exposed under general anaesthesia in 18 adult Sprague-Dawley rats. In 12 animals, the nerve was sectioned and immediately re-approximated using four epineurial sutures, and in 6 of these animals neutralising antibodies to transforming growth factor (TGF)-beta1 and TGF-beta2 were injected into and around the repair site. The six other animals acted as controls. After 7 weeks, the outcome was assessed by recording compound action potential (CAP) ratios, measuring collagen levels using picrosirius red staining, and counting the number of myelinated axons proximal and distal to the repair. After repair alone, the mean percentage of area of staining (PAS) for collagen within the nerve had significantly increased. However, after repair with the administration of antibodies, the PAS was not significantly different from that in the sham controls. After administration of antibodies, the CAP ratios were significantly smaller than in controls but not after repair alone. In both nerve injury groups, the myelinated fibre counts were significantly increased distal to the injury site, but there was no difference between these two groups. We conclude that administration of antibodies to TGF-beta1 and TGF-beta2 reduced scar formation at the repair site but did not enhance regeneration of the nerve or reduce the development of multiple axonal sprouts.

Coincidence of connective tissue growth factor expression with fibrosis and angiogenesis in postoperative peritoneal adhesion formation

PURPOSE

To investigate the relationship between connective tissue growth factor (CTGF) and fibrosis and angiogenesis in postoperative peritoneal adhesion formation.

METHODS

Adhesions were performed in 35 rats by creation of a peritoneal patch. Animals were sacrificed at 7 different time-points over 3 weeks. Adhesions and uninjured peritoneum from all animals were assessed by Northern blotting for CTGF and collagen-I mRNA and by immunohistochemistry for CTGF localization, degree of fibrosis and angiogenesis.

RESULTS

Persistent adhesions formed in all animals. CTGF and collagen-I mRNA were increased in adhesions compared to uninjured peritoneum (p < 0.05 for both). The temporal expression pattern depicted delayed peak levels of collagen-I mRNA with increasing tendency for both transcripts at the end of the observation period. Fibrosis within adhesions correlated positively with time after surgery (r = 0.85; p < 0.001) and showed typical signs of chronic tissue fibrosis at later time points. Angiogenesis was detected in adhesions but not in uninjured peritoneum (p = 0.001) and coincided with the spatial and temporal expression of CTGF protein in fibroblasts and vascular endothelial cells.

CONCLUSIONS

The co-expression of CTGF with increasing fibrosis and angiogenesis in postoperative peritoneal adhesions suggests a role for CTGF as critical molecule in fibrous adhesive disease and target for future adhesion prevention.

Experimental manipulation of transforming growth factor-beta isoforms significantly affects adhesion formation in a murine surgical model

Transforming growth factor-beta (TGF-beta), a multifunctional growth factor, represents three mammalian isoforms, TGF-beta1, TGF-beta2, and TGF-beta3. In cutaneous wound healing, combined neutralization of TGF-beta1 and -beta2 or addition of TGF-beta3 reduces scar formation. Here, we investigated whether experimental manipulation of TGF-beta isoforms reduced adhesion formation after injury to the peritoneum. Adhesions were produced in mice by surgical abrasion of adjacent serosa followed by close apposition. In the first part of this study, a detailed analysis of TGF-beta isoform distribution was performed through immunolocalization. TGF-beta isoforms clearly showed a unique temporal and spatial pattern of expression after peritoneal wounding. Based on this pharmacokinetic data, we next administered neutralizing antibodies to TGF-beta1 and -beta2 or exogenous TGF-beta3 peptide by local application and intraperitoneal injection at various times before and after surgery. At day 7 after surgery, addition of neutralizing antibodies to both TGF-beta1 and -beta2 significantly reduced the number and size of adhesions (P < 0.05) compared with the vehicle control. By contrast, exogenous addition of TGF-beta3 either had no effect or increased adhesion formation compared to the vehicle control. In conclusion, these results show that by blocking both TGF-beta1 and TGF-beta2 using neutralizing antibodies, it is possible to prevent abdominal adhesion formation.

Can angiotensin converting enzyme inhibitors prevent postoperative adhesions?

BACKGROUND

Peritoneal adhesions are pathological fibrotic bands developing after mesothelial damage. Transforming growth factor beta-1 (TGF-beta1) has mitogenic activities for macrophages and fibroblasts. Over-expression of TGF-beta1 has been implicated in the pathogenesis of several fibrotic disorders. Angiotensin II increases the expression of the TGF-beta1 in fibroblasts. The aim of the study was to investigate the effect of angiotensin converting enzyme inhibitor (ACE) on intraperitoneal adhesions.

MATERIALS AND METHODS

Thirty male Wistar albino rats were divided into two groups. In the first procedure, laparotomy was performed through a 3-cm midline incision. Ileum was divided above 10 cm from ileocecal valve and a single-layer ileoileal anastomosis was performed. Although no treatment was given to rats in group 1, lisinopril (an ACE inhibitor) was given to rats in group 2 for postoperative 7 days in drinking water. Estimated amount of supplied lisinopril was 6.5 mg/kg/day. On postoperative 8th day, relaparotomy was performed and adhesions were evaluated. At the same time, blood samples were taken for TGF-beta1 measurements.

RESULTS

Adhesion severity was significantly less in the ACE inhibitor group (P < 0.001). While mean TGF-beta1 level was 860.3 +/- 108.1 pg/dl (mean +/- SD) in control group, it was 335.8 +/- 52.4 pg/dl in ACE inhibitor group (P < 0.001). There was a significant correlation between serum TGF-beta1 levels and grade of adhesions (r = 0.948).

CONCLUSION

It was concluded that ACE inhibitors might be useful for preventing peritoneal adhesions.

Therapeutic applications of chymase inhibitors in cardiovascular diseases and fibrosis

Chymase activates not only angiotensin I to angiotensin II but also latent transforming growth factor-beta-binding protein to transforming growth factor-beta. In dog grafted veins, chymase activity and angiotensin II concentration along with vascular proliferation were significantly increased, while they were significantly suppressed by a chymase inhibitor. After balloon injury in dog arteries, chymase activity was significantly increased in the injured artery, and a chymase inhibitor and an angiotensin AT(1) receptor antagonist were effective in preventing the vascular proliferation, but an angiotensin-converting enzyme inhibitor was ineffective. In fibrotic models, the tissue fibrosis was reduced by chymase inhibitors. In adhesion models, the transforming growth factor-beta concentration and adhesion formation were suppressed by chymase inhibitors. Therefore, chymase inhibitors may be useful for preventing cardiovascular diseases and fibrosis via inhibition of angiotensin II formation and transforming growth factor-beta activation.

Seprafilm (modified hyaluronic acid and carboxymethylcellulose) acts as a physical barrier

OBJECTIVE

To characterize the molecular changes that occur in normal fibroblasts, adhesion fibroblasts, and mesothelial cells as a result of exposure to modified hyaluronic acid and carboxymethylcellulose (Seprafilm).

SETTING

University research laboratory.

DESIGN

Human mesothelial and fibroblast cell culture.

MAIN OUTCOME MEASURE(S)

Multiplex reverse transcriptase polymerase chain reaction was used to examine control and Seprafilm-treated normal peritoneal fibroblasts, adhesion fibroblasts, and mesothelial cells in culture for levels of messenger RNA from molecules known to be associated with adhesion development (transforming growth factor-beta 1, type I collagen, matrix metalloproteinase-1, matrix metalloproteinase-2, tissue inhibitor of metalloproteinase-1, and tissue plasminogen activator).

RESULT(S)

Seprafilm treatment of normal peritoneal fibroblasts, adhesion fibroblasts and mesothelial cells did not alter the expression of markers examined.

CONCLUSION(S)

In the absence of a biological effect of Seprafilm on markers known to be involved in postoperative adhesion development, the ability of Seprafilm to reduce postoperative adhesions is most likely caused by its effect as a physical barrier.

Neoadjuvant antiangiogenic therapy with tamoxifen does not impair gastrointestinal anastomotic repair in the rat

INTRODUCTION

Antiangiogenic therapy has the potential to moderate tumour and micrometastatic growth. Its use in the perioperative period is attractive but its potential to compromise wound and anastomotic healing is a cause for concern. Tamoxifen is antiangiogenic but also favourably modifies some aspects of wound healing. We hypothesised that tamoxifen would not adversely affect skin wound and gut anastomotic healing.

METHODS

A previously established model of tamoxifen, administered orally at antiangiogenic doses (20 mg/ml arachais oil/day), was used. Animals received two days pretreatment prior to laparotomy and small bowel anastomosis. Treatment was continued until completion of the study. The principal outcome measures are survival, macroscopic wound and anastomotic healing, anastomotic bursting pressure and PVA sponge granuloma hydroxyproline (OHP) content.

RESULTS

Tamoxifen treated animals had fewer complications of skin wound healing than controls (4.5% vs. 19.5%; chi(2) 4.65, 1 d.f., P < 0.05). There was no significant difference in adhesion formation or macroscopic complications of anastomotic healing. Anastomotic bursting pressure was greater in tamoxifen treated animals at postoperative day 3 (39 +/- 4.4 vs. 22.5 +/- 3.5 mmHg; P < 0.01) and equal to that of controls on postoperative day 5 (144.4 +/- 9.4 vs. 127.3 +/- 10.9 mmHg; P = ns). Tamoxifen treated animals weighed significantly less than placebo controls from postoperative day 3 with no difference in mortality between groups (chi(2) = 0.06, 1 d.f., P = ns). PVA sponge granuloma OHP content on day 7 was higher in tamoxifen-treated animals (2.93 +/- 0.4 vs. 1.4 +/- 0.4 mg OHP/mg dry sponge weight; P = 0.03).

CONCLUSION

Antiangiogenic therapy with tamoxifen has no demonstrable adverse effects on wound or anastomotic repair and its perioperative use is compatible with successful early surgical outcomes.

Regulation of transforming growth factor-beta, type III collagen, and fibronectin by dichloroacetic acid in human fibroblasts from normal peritoneum and adhesions

OBJECTIVE

To examine the role of aerobic metabolism in fibroblasts from normal peritoneum and adhesions in the differential expression of extracellular matrix (ECM) and transforming growth factor-beta (TGF-beta), an inflammatory cytokine that regulates ECM expression.

DESIGN

Cell culture under normoxic and hypoxic conditions.

SETTING

University research laboratory.

PATIENT(S)

Human fibroblasts cultures from normal peritoneum and adhesions.

INTERVENTION(S)

Exposure to dichloroacetic acid (DCA), which activates pyruvate dehydrogenase, for 24 hours under normal and hypoxic (2% O(2)) conditions.

MAIN OUTCOME MEASURE(S)

Multiplex reverse transcriptase polymerase chain reaction (RT/PCR) of type III collagen, fibronectin, TGF-beta1, and beta-actin was performed, with analysis of PCR-amplified products performed by densimetric analysis of gel bands using the National Institutes of Health Image analysis program.

RESULT(S)

DCA inhibited human peritoneal fibroblast and adhesion fibroblast TGF-beta1 mRNA expression under normoxic and hypoxic conditions. DCA also markedly reduced fibronectin and type III collagen expression under hypoxic conditions in fibroblasts from normal peritoneum and adhesions.

CONCLUSION(S)

These observations provide further support for the suggestion that regulation of metabolic activity of peritoneal cells may provide a target for interventions designed to reduce postoperative adhesions.

Adhesion of endometrial cells labeled with 111Indium-tropolonate to peritoneum: a novel in vitro model to study endometriosis

OBJECTIVE

To evaluate, in a new original in vitro assay, putative factors that could modulate the adhesion of endometrial cells to peritoneum.

DESIGN

Prospective, controlled in vitro study.

SETTING

Academic research laboratory.

PATIENT(S)

Fourteen nonmenopausal women undergoing hysterectomy or laparoscopy for benign gynecologic indication.

INTERVENTION(S)

Endometrial cells obtained from women with regular cycles without endometriosis were labeled with 111Indium and confronted in vitro with mouse peritoneum in the presence of various cytokines and/or antiadhesive compounds.

MAIN OUTCOME MEASURE(S)

Radioactivity in 111Indium-labeled endometrial cells.

RESULT(S)

The adhesion of human endometrial cells to mouse peritoneum was increased by treatment with pro-inflammatory cytokines (interleukin IL-1beta, IL-6, TNF alpha, TGF-beta1). Whereas heparan sulfate had no effect on cell adhesion, a gel of ferric hyaluronate (Intergel) was able to counteract the pro-adhesive effect of cytokines. Interestingly, the pretreatment of peritoneum with cytokines, 24 hours before cell seeding in the presence of the ferric hyaluronate gel, restored the cytokine-promoting effect on cell adhesion.

CONCLUSION(S)

Proinflammatory cytokines promote the in vitro peritoneal adhesion of endometrial cells. An antiadhesive hyaluronate gel used in clinics decreases the adhesion in a dose-dependent manner and reduces cytokine bioavailability.