Angiogenic factors in peritoneal adhesion formation

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

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

Anti-adhesive effect of chondrocyte-derived extracellular matrix surface-modified with poly-L-lysine (PLL)

After an injury, soft tissue structures in the body undergo a natural healing process through specific phases of healing. Adhesions occur as abnormal attachments between tissues and organs through the formation of blood vessels and/or fibrinous adhesions during the regenerative repair process. In this study, we developed an adhesion-preventing membrane with an improved physical protection function by modifying the surface of chondrocyte-derived extracellular matrices (CECM) with anti-adhesion function. We attempted to change the negative charge of the CECM surface to neutral using poly-L-lysine (PLL) and investigated whether it blocked fibroblast adhesion to it and showed an improved anti-adhesion effect in animal models of tissue adhesion. The surface of the membrane was modified with PLL coating (PLL 10), which neutralized the surface charge. We confirmed that the surface characteristics except for the potential difference were maintained after the modification and tested cell attachment in vitro. Adhesion inhibition was identified in a peritoneal adhesion animal model at 1 week and in a subcutaneous adhesion model for 4 weeks. N-CECM suppressed fibroblast and endothelial cell adhesion in vitro and inhibited abdominal adhesions in vivo. The CECM appeared to actively inhibit the infiltration of endothelial cells into the injured site, thereby suppressing adhesion formation, which differed from conventional adhesion barriers in the mode of action. Furthermore, the N-CECM remained intact without degradation for more than four weeks in vivo and exerted anti-adhesion effects for a long time. This study demonstrated that PLL10 surface modification rendered a neutral charge to the polymer on the extracellular matrix surface, thereby inhibiting cell and tissue adhesion. Furthermore, this study suggests a means to modify extracellular matrix surfaces to meet the specific requirements of the target tissue in preventing post-surgical adhesions. This article is protected by copyright. All rights reserved.

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.

Postoperative peritoneal adhesion: an update on physiopathology and novel traditional herbal and modern medical therapeutics

Postoperative peritoneal adhesion (PPA) is a serious clinical condition that affects the high percentage of patients after abdominal surgery. In this review, we have tried to focus on pathophysiology and different underlying signal pathways of adhesion formation based on recent progress in the molecular and cellular mechanisms. Also, the strategies, developed based on traditional herbal and modern medicines, to prevent and treat the PPA via regulation of the molecular mechanisms were investigated. The search engines such as Google Scholar, PubMed, Scopus, and Science Direct have been used to evaluate the current literature related to the pathogenesis of adhesion formation and novel products. Recently, different mechanisms have been defined for adhesion formation, mainly categorized in fibrin formation and adhesion fibroblast function, inflammation, and angiogenesis. Therefore, the suppression of these mechanisms via traditional and modern medicine has been suggested in several studies. While different strategies with encouraging findings have been developed, most of the studies showed contradictory results and were performed on animals. The herbal products have been introduced as safe and effective agent which can be considered in future preclinical and clinical studies. Although a wide range of therapeutics based on traditional and modern medicines have been suggested, there is no agreement in the efficacy of these methods to prevent or treat adhesion formation after surgeries. Further basic and clinical researches are still needed to propose the efficiency of recommended strategies for prevention and treatment of PPA.

Addition of nitrous oxide to the carbon dioxide pneumoperitoneum strongly decreases adhesion formation and the dose-dependent adhesiogenic effect of blood in a laparoscopic mouse model

OBJECTIVE

To evaluate the effect of addition of nitrous oxide (N2O) to the carbon dioxide (CO2) pneumoperitoneum (PP) and the effect of blood, plasma, or red blood cells (RBCs) on postoperative adhesions in a laparoscopic mouse model.

DESIGN

Prospective randomized controlled trial.

SETTING

University laboratory research center.

ANIMAL(S)

BALB/c female mice.

INTERVENTION(S)

The effect of adding to the 60-minute CO2 PP 5%, 10%, 25%, 50%, or 100% N2O on adhesion formation was evaluated. Subsequently the effect of adding 1 mL blood, or RBCs, or plasma and the effect of adding different concentrations of blood were studied. Finally, the effect of adding 10% N2O, 4% O2, or both to the CO2 was evaluated in a control group and after addition of blood.

MAIN OUTCOME MEASURE(S)

Postoperative adhesions after 7 days.

RESULT(S)

N2O strongly reduces adhesion formation with a full effect at a concentration of 5% or 10%. Adhesions increase linearly with 0.125 mL to 1 mL blood. In both the control group and after adding blood, 10% N2O is the most effective factor in prevention of adhesions.

CONCLUSION(S)

N2O, from concentrations of 5% upward, strongly prevents adhesion formation. Blood, mainly the plasma, increases adhesion formation. These data extend the concept of the role of acute inflammation and support the importance of good surgical practice with little bleeding and peritoneal cavity conditioning in adhesion prevention.

Physical and biological effects of gellan gum on decreasing postoperative adhesion in a rat model

An antiadhesion membrane made from gellan gum was fabricated and characterized. A 12-µm-thick membrane of gellan gum was prepared and reacted with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide to obtain a cross-linked membrane (G/A70) with 87% gel content and a tensile strength of 46.5 MPa. In vivo, the G/A70 membrane had 90% less tissue adhesion. Inflammation-related and extracellular matrix protein gene expression in a rat model of abdominal surgery was found by real-time quantitative reverse transcription polymerase chain reaction analysis. On day 3, after surgery, the gene expression of ceruloplasmin and type V collagen in the G/A70-treated group was 1.9 and 0.3 times that of the control group, respectively. The G/A70 membrane elicited mild inflammation but suppressed type V collagen synthesis and reduced the occurrence of tissue adhesion. These findings provide insights into the properties of gellan gum antiadhesion membranes and help to overcome problems involving tissue adhesions in surgical procedures.

Oral traditional Chinese medication for adhesive small bowel obstruction

BACKGROUND

Small bowel obstruction (SBO) is one of the most common emergent complications of general surgery. Intra-abdominal adhesions are the leading cause of SBO. Because surgery can induce new adhesions, non-operative management is preferred in the absence of signs of peritonitis or strangulation. Oral traditional Chinese herbal medicine has long been used as a non-operative therapy to treat adhesive SBO in China. Many controlled trials have been conducted to investigate its therapeutic value in resolving adhesive SBO.

OBJECTIVES

The aim of this review was to assess the efficacy and safety of oral traditional Chinese medicine (TCM) for adhesive small bowel obstruction.

SEARCH METHODS

We searched the following databases, without regard to language or publishing restrictions: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Chinese Biomedical Database (CBM), China National Knowledge Infrastructure/Chinese Academic Journals full-text Database (CNKI), and VIP (a full-text database of Chinese journals). The searches were conducted in November 2011.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials comparing Chinese medicines administered orally, via the gastric canal, or both with a placebo or conventional therapy in participants diagnosed with adhesive SBO were considered. We also considered trials of TCM (oral administration, gastric tube perfusion, or both) plus conventional therapy compared with conventional therapy alone for patients with adhesive SBO. Studies addressing the safety and efficacy of oral traditional Chinese medicinal agents in the treatment of adhesive SBO were also considered.

DATA COLLECTION AND ANALYSIS

Two authors collected the data independently. We assessed the risk of bias according to the following methodological criteria: random sequence generation, allocation concealment, blinding, incomplete outcome data, selective outcome reporting and other sources of bias. Dichotomous data are presented as risk ratios (OR) and 95% confidence intervals (CI); continuous outcomes are presented as mean differences (MD) and 95% CIs. The data analyses were carried out using Review Manager 5.1. For cases in which necessary information was not reported in the paper, we contacted the primary authors for additional information.

MAIN RESULTS

Five randomised trials involving 664 participants were analysed. Five different herbal medicines were tested in these trials, including Huo-Xue-Tong-Fu decoction, Xiao-Cheng-Qi-Tang decoction, a combination of Xiao-Cheng-Qi-Tang and Si-Jun-Zi-Tang decoctions, Chang-Nian-Lian-Song-Jie-Tang decoction, and Fufang-Da-Cheng-Qi-Tang decoction. There were variations in the tested herbal compositions and methods of medicine administration. The main outcomes reported in the trials were effects on abdominal pain, abdominal distension, constipation defection, time of first defecation after treatment, and reoperation rate during the course of the disease. Secondary outcomes selected for this review were not available, including complications such as small bowel perfusion (bowel resection, system complications, and other possible complications), length of hospital stay, cost of hospitalisation, and time from admission to surgical intervention. The results of five trials showed that patients receiving TCM combined with conventional therapy seemed to have improved outcomes compared with patients receiving conventional treatment alone (OR 4.24, 95% CI 2.83 to 6.36).However, we cannot conclusively determine the efficacy of TCM in this review due to inadequate reporting, low methodological quality, and the prevalence of various biases in the reviewed studies. Furthermore, because none of the reviewed trials discussed adverse events, we could not evaluate the safety of TCM for adhesive SBO patients. All trials were conducted and published in China.

AUTHORS' CONCLUSIONS

Although many studies have assessed the use of TCM products for adhesive SBO, most were excluded from this review due to their methodological limitations. This systematic review did not find sufficient evidence to support the objective efficacy and safety of TCM for patients with adhesive SBO. The positive evidence should be interpreted with caution given the insufficient number of studies with large sample sizes, the absence of well-designed, high-quality trials, and the lack of safety information. Therefore, further studies with larger sample sizes and high-quality, randomised, and controlled trials are necessary to produce more accurate and meaningful data on the efficacy of Chinese herbal medicines for adhesive SBO.

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.