Effects of TC7 associated to 32% dextran 70, heparin and carboxymethylcellulose in adhesion prevention in the rat

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.

Efficacy of barriers and hypoxia-inducible factor inhibitors to prevent CO(2) pneumoperitoneum-enhanced adhesions in a laparoscopic mouse model

STUDY OBJECTIVE

To investigate the effects of hypoxia-inducible factor (HIF) inhibitors, flotation agents, barriers, and a surfactant on pneumoperitoneum-enhanced adhesions in a laparoscopic mouse model.

DESIGN

Prospective randomized trial (Canadian Task Force classification I).

SETTING

Department of Obstetrics and Gynecology, University Hospital Gasthuisberg, Catholic University of Leuven.

SUBJECTS

One hundred fourteen female BALB/c mice.

INTERVENTIONS

Adhesions were induced during laparoscopy in BALB/c female mice. Pneumoperitoneum was maintained for 60 minutes with humidified CO(2). In 3 experiments the effects of HIF inhibitors such as 17-allylamino 17-demethoxygeldanamycin, radicicol, rapamycin, and wortmanin, flotation agents such as Hyskon and carboxymethylcellulose, barriers such as Hyalobarrier gel and SprayGel, and surfactant such as phospholipids were evaluated.

MEASUREMENTS AND MAIN RESULTS

Adhesions were scored after 7 days during laparotomy. Adhesion formation decreased with the administration of wortmannin (p <.01), phospholipids (p <.01), Hyalobarrier Gel (p <.01), and SprayGel (p <.01).

CONCLUSIONS

These experiments confirm the efficacy of barriers and phospholipids to separate or lubricate damaged surfaces. They also confirm the role of mesothelial hypoxia in this model by the efficacy of the HIF inhibitor wortmannin.

Efficacy of a hyaluronan derivative gel in postsurgical adhesion prevention in the presence of inadequate hemostasis

BACKGROUND

We previously demonstrated that an auto-cross-linked hyaluronan-based antiadhesion agent (auto-cross-linked polysaccharide [ACP] gel) was effective in postsurgical adhesion prevention after open laparotomy and laparoscopic surgery with adequate hemostasis in animal models. This study assessed the ability of different preparations of ACP gel to prevent adhesions in the presence of bleeding or inadequate hemostasis.

METHODS

Ninety-seven female rabbits were subjected to a standardized surgical lesion with subsequent exudative abdominal bleeding (oozing model), and 97 animals were subjected to a standardized surgical lesion with severe abdominal bleeding (bleeding model). After injury, the animals were randomly assigned to 5 groups of treatment: 3 different preparations of ACP gel (20, 40, and 60 mg/mL), a hyaluronan-carboxymethylcellulose film, and no treatment. Three weeks after operation, the animals were killed, and the adhesions were assessed by a blinded observer who measured the length and area of the adhesions and who used the Blauer scoring system.

RESULTS

All 3 preparations of ACP gel and the hyaluronan-carboxymethylcellulose film reduced adhesion formation in both models (P <.01) as measured by the number of adhesion-free animals, mean Blauer score, and the mean length and surface area of the adhesions. There were no statistical differences between the different treatment groups.

CONCLUSIONS

These data suggest that different hyaluronan based agents in the presence of severe bleeding or exudative abdominal bleeding reduce de-novo postsurgical adhesion formation.

Comparison of Antiadhesive Treatments using an Objective Rat Model

Intraperitoneal adhesions are a significant problem (increased morbidity, mortality, and cost) for patients undergoing abdominal procedures. Although a variety of approaches (e.g., fibrinolytic agents, anti-inflammatory drugs, or barrier/separation methods) have been used with some success in preventing adhesions, a comparison of these different modalities has yet to be performed in a model that objectively measures intraperitoneal adhesion formation. Our objectives were to establish an objective, reproducible model of intraperitoneal adhesion formation and to establish efficacy of different treatment modalities in decreasing the strength and extent of intraperitoneal adhesions. In this two-part study, a rat model establishing an objective measure of both the strength and extent of intraperitoneal adhesions was used to compare different treatment modalities. Fibrinolytic agents [recombinant tissue plasminogen activator (rtPA), streptokinase, and urokinase], anti-inflammatory drugs (dexamethasone and tolmetin sodium), and barrier methods [sodium carboxymethylcellulose (CMC), and sodium hyaluronate] and a control group were compared in the first phase. In the second phase, the two most successful agents (rtPA, CMC) were compared both alone and in combination against a commercially available barrier agent (Seprafilm™) and a control group. In the first phase of the study, rtPA was the only agent that had a statistically significant effect in decreasing the strength of adhesions. CMC was the only agent that demonstrated a decrease in the extent of adhesions, and the difference tended toward significance. In the second phase, the combination of rtPA and CMC showed a significant decrease in both the strength and extent of adhesions when compared with those of the control group. This decrease was also observed in the group treated with Seprafilm™, which showed no difference from the rtPA + CMC group. We conclude that, in this reproducible adhesion model, only the combination of rtPA + CMC and Seprafilm™ significantly reduced both the strength and the extent of intraperitoneal adhesions.