The use of statins in postoperative adhesion prevention

Prevention of Intra-Abdominal Adhesions Using the Combination of Mediclore® and a Statin

PURPOSE

This study investigated the antiadhesive effects of Mediclore®, rosuvastatin, and a combination of Mediclore and rosuvastatin in a rat adhesion model.

METHODS

The adhesion models (a total of 58 adult male rats) were divided into 4 groups. The control group (group C) received no special materials except for a saline. The experimental groups were treated with 5 mL of Mediclore (group M), rosuvastatin (group R), or rosuvastatin and Mediclore (group RM), and these materials were intraperitoneally placed under the incision. At postoperative day 14, the rats underwent re-laparotomy and adhesiolysis. Three investigators blinded to group assignment scored the extent of adhesion formation, the numbers of remote adhesions, and the extent of acute/chronic inflammation, fibrosis, edema, and congestion on resected specimens via histologic examination.

RESULTS

The macroscopic adhesion score in group RM (7.27 ± 3.51) was significantly lower than those in groups C (13.36 ± 2.24) and R (11.71 ± 1.98); group M (9.13 ± 4.09) had a significantly lower adhesion score than group C. The number of remote adhesions was significantly lower in groups R and RM than in group C. The acute inflammation score, chronic inflammation score, and fibrosis score in group RM; the acute inflammation score in group R; and the fibrosis score in group M were significantly lower than those in group C.

CONCLUSION

The intraperitoneal application of Mediclore and a combination of Mediclore and rosuvastatin effectively reduced postoperative adhesions.

Spin-coated freestanding films for biomedical applications

Spin-coating is a widely employed technique for the fabrication of thin-film coatings over large areas with smooth and homogeneous surfaces. In recent years, research has extended the scope of spin-coating by developing methods involving the interface of the substrate and the deposited solution to obtain self-supported films, also called freestanding films. Thereby, such structures have been developed for a wide range of areas. Biomedical applications of spin-coated freestanding films include wound dressings, drug delivery, and biosensing. This review will discuss the fundamental physical and chemical processes governing the conventional spin-coating as well as the techniques to obtain freestanding films. Furthermore, developments within this field with a primary focus on tissue engineering applications will be reviewed.

Effect of statins on experimental postoperative adhesion: a systematic review and meta-analysis

Adhesion is a significant concern after surgery. Many researchers studied the anti-adhesive effect of statin, of which results were inconsistent. Thus, we purposed to perform a systematic review and meta-analysis to evaluate the effect of statins on postoperative adhesion in an experimental study. A comprehensive search was conducted using MEDLINE, EMBASE, and Google Scholar to identify animal studies that investigated the postoperative anti-adhesive effect of statins applied at the surgical area. Primary outcome measure was gross adhesion score. Secondary outcomes included microscopic adhesion score and tissue plasminogen activator (t-PA) activity. Totally, 298 rats from 9 animal studies (172 rats received statin therapy and 126 rats received placebo or no treatment) were included in the final analysis. The combined results showed that gross and microscopic adhesion scores were significantly lower in the statin group in comparison to the control group (standardized mean difference [SMD] = 1.65, 95% confidence interval [CI]: 1.02 to 2.28, P_chi² < 0.001, I² = 77.9%; SMD = 1.90, 95% CI: 1.10 to 2.79, P_chi² < 0.001, I² = 84.5%, respectively). However, there was no evidence of a difference in t-PA activity (SMD = -3.43, 95% CI: -7.95 to 1.09, P_chi² < 0.001, I² = 95.5%). In conclusion, statins were effective in preventing postoperative adhesion, as assessed based on gross and microscopic adhesion scores in rats.

Evaluation of topical application and systemic administration of rosuvastatin in preventing epidural fibrosis in rats

BACKGROUND CONTEXT

Epidural fibrosis is a major challenge in spine surgery, with some patients having recurrent symptoms secondary to excessive formation of scar tissue resulting in neurologic compression. One of the most important factors initiating the epidural fibrosis is assumed to be the transforming growth factor-1β (TGF-1β). Rosuvastatin (ROS) has shown to demonstrate preventive effects over fibrosis via inhibiting the TGF-1β.

PURPOSE

We hypothesized that ROS might have preventive effects over epidural fibrosis through the inhibition of TGF-1β pathways.

STUDY DESIGN

Experimental animal study.

METHODS

Forty-eight adult male Wistar Albino rats were equally and randomly divided into four groups (laminectomy, spongostan, topical ROS, and systemic ROS). Laminectomy was performed at the L3 level in all rats. Four weeks later, the extent of epidural fibrosis was assessed both macroscopically and histopathologically.

RESULTS

Our data revealed that topical application and systemic administration of ROS both were effective in reducing epidural fibrosis formation. Furthermore, the systemic administration of ROS yielded better results than topical application.

CONCLUSIONS

Both topical application and systemic administration of ROS show meaningful preventive effects over epidural fibrosis through multiple mechanisms. The results of our study provide the first experimental evidence of the preventive effects of ROS over epidural fibrosis.

Peritoneal response to abdominal surgery: the role of equine abdominal adhesions and current prophylactic strategies

Intra-abdominal adhesions constitute a significant clinical and surgical problem that can lead to complications such as pain and bowel occlusion or subocclusion. These adhesions are frustrating and potentially fatal, representing a major postoperative complication in abdominal surgery. It is estimated that 32% of horses undergoing laparotomy will present clinical symptoms due to adhesions, but the true prevalence is not known because a large proportion of animals with postoperative recurrent colics are medically treated or submitted to euthanasia without necropsy. Adhesions are highly cellular, vascularized, dynamic structures that are influenced by complex signaling mechanisms. Understanding their pathogenesis could assist in applying better therapeutic strategies and in developing more effective antiadhesion products. Currently, there are no definitive strategies that prevent adhesion formation, and it is difficult to interpret the results of existing studies due to nonstandardization of an induction model and evaluation of their severity. The best clinical results have been obtained from using minimally traumatic surgical techniques, anti-inflammatory agents, antimicrobials, anticoagulants, and mechanical separation of serosal surfaces by viscous intraperitoneal solutions or physical barriers. This paper aims to review adhesion formation pathogenesis, guide the understanding of major products and drugs used to inhibit adhesion formation, and address their effectiveness in the equine species.

Postoperative adhesion prevention using a statin-containing cellulose film in an experimental model

BACKGROUND

Intraperitoneal adhesions are a common problem in abdominal surgery. The aim of this study was to compare the effectiveness of Statofilm, a novel antiadhesive film based on cross-linked carboxymethylcellulose and atorvastatin, with that of sodium hyaluronate-carboxymethylcellulose (Seprafilm(®)) in the prevention of postoperative intraperitoneal adhesions in rats.

METHODS

One hundred male Wistar rats underwent a laparotomy and adhesions were induced by caecal abrasion. The animals were allocated to five groups: a control group with no adhesion barrier, Seprafilm(®) group, placebo group with a film containing carboxymethylcellulose without atorvastatin, and low- and high-dose groups with films containing carboxymethylcellulose and atorvastatin 0·125 and 1 mg per kg bodyweight respectively. Adhesions were classified by two independent surgeons 2 weeks after surgery. Caecal biopsies were obtained for histological evaluation of fibrosis, inflammation and vascular proliferation.

RESULTS

All antiadhesive film groups (Seprafilm(®), placebo, low-dose and high-dose) had statistically significant adhesion reduction compared with the control group (P < 0·001, P = 0·015, P < 0·001 and P < 0·001 respectively). The low-dose Statofilm was superior to Seprafilm(®) in terms of adhesion prevention (P = 0·001). Adhesions were present in three-quarters of rats in the Seprafilm(®) group, but only one-quarter in the low-dose Statofilm group.

CONCLUSION

The data suggest that the newly developed adhesion barrier Statofilm has better results than Seprafilm(®) in preventing postoperative adhesions in rats. A low-dose atorvastatin-containing film, such as Statofilm, could be evaluated for future clinical application.

Intra-abdominal use of phosphodiesterase type 4 inhibitor in postoperative adhesion prevention: an experimental study on mice

OBJECTIVE

The study was designed to assess the value of intraperitoneal use of rolipram for adhesion prevention and to compare the results with placebo and a sodium hyaluronate/carboxymethylcellulose absorbable barrier (Seprafilm), in a murine cecal abrasion model.

DESIGNS

Twenty-four Balb/c mice were subjects of this study. Intra-abdominal adhesions were created with a multiple-abrasion model consisting of meticulous abrasion of the cecum and small-bowel segments with strokes of a dental toothbrush. Animals in groups R (n = 8) received 1 mL of rolipram intraperitoneally. Seprafilm was placed over the viscera under the incision in group S animals (n = 8). Group C animals (n = 8) were reserved as control and received nothing. Animals were killed on day 22.

MAIN OUTCOME MEASURES

The adhesions were evaluated with 2 different observational scoring systems, the Majuzi System and the Linsky Scale. After completion of observational evaluation, the cecum and small bowel of the animals were excised and sent to the pathology laboratory for histopathologic examination. The extent of inflammatory response, the extent of the fibrotic reaction, the extent of the necrosis and abscess formation, and the extent of foreign body reaction were histologically evaluated.

RESULTS

The mean Majuzi System scores of groups R and S were similar to each other and significantly less than control group. Also, all scores of the Linsky Scale in group R were similar to those in group S, and significantly less than those in the control group. Histologically, the mean score of inflammatory response in group R was less than both those in group C and group S. The mean score of fibrotic reaction in group R was significantly less than those in the control group.

CONCLUSION

These results indicate that rolipram may be an effective material in prevention of postoperative intra-abdominal adhesions, but it is obvious that further studies are needed to validate the results of this limited initial study.

Preventing intraperitoneal adhesions with atorvastatin and sodium hyaluronate/carboxymethylcellulose: a comparative study in rats

OBJECTIVES

The aim of this study was to compare the effectiveness of atorvastatin with the sodium hyaluronate/carboxymethylcellulose (HA/CMC, Seprafilm; Genzyme; Genzyme Biosurgery Corporation, Cambridge, MA) in preventing postoperative intraperitoneal adhesion formation in rats.

METHODS

Sixty Wistar rats underwent a laparotomy, and adhesions A were induced by cecal abrasion. The animals were divided into 4 groups: group 1, control A; group 2, (A + atorvastatin); group 3, (A + HA/CMC), and group 4, (A + atorvastatin + HA/CMC). The atorvastatin (groups 2 and 4) and HA/CMC (groups 3 and 4) were administered intraperitoneally before the abdominal wall was closed. After 14 days, adhesions were classified by 2 independent surgeons.

RESULTS

The adhesion scores (mean +/- standard deviation) for groups 1, 2, 3, and 4 were 2.93 +/- .59, 1.85 +/- 1.07, 1.80 +/- .86, and 1.93 +/- .70, respectively. The differences in adhesion scores among all 3 preventive groups (groups 2, 3, and 4) were statistically significant when compared with the control group (P = .005, P = .002, and P = .009, respectively).

CONCLUSIONS

These data suggest that atorvastatin, administered intraperitoneally, is as effective as HA/CMC without an expectable additive effect in preventing postoperative adhesions in rats.

Prevention of postoperative peritoneal adhesions

Adhesions are bands of tissue that connect organs together. It is frequently reported after surgery and remains a major problem for health and society. Efforts to prevent or reduce peritoneal adhesions mostly have been unsuccessful, hindered by their empirical basis, lack of good predictive animal models and complexity of adhesion pathogenesis. Although a good surgical technique is a crucial part of adhesion prevention, the technique alone cannot effectively eliminate the adhesions. Thus, there remains a room for further research. A comprehensive literature review of published experimental and clinical studies of adhesion prevention was carried out at the University of Bristol electronic library (MetaLib) with cross-search of seven different medical databases (AMED-Allied and Complementary Medicine Database, BIOSIS Previews on Web of Knowledge, Cochrane Library, Embase and Medline on Web of Knowledge, OvidSP and PubMed) by using key words (peritoneal adhesions, postoperative adhesions, prevention) to explore the progress in different surgical strategies and adjuvant materials used to prevent adhesions formation and reformation. By the end of the study, recommendations formulated for surgeons to be followed during the operations to prevent, as much as possible, the postoperative adhesions.

Use of statins in adhesive small bowel obstruction

BACKGROUND

Adhesive small bowel obstruction (ASBO) causes considerable morbidity and may require surgical intervention. The role of statins in adhesion prevention is of increasing interest, though no investigation of its impact on ASBO and operative rates has been conducted. This study investigates the impact of statin use on operative rates in ASBO.

METHODS

A retrospective review of all patients with ASBO within our institution from January 1997 to December 2007 was conducted. Demographic data, potential confounders, and treatment received (conservative/operative) were recorded. Statistical significance was determined using the two-tailed Fisher's exact test for categorical data and the Mann-Whitney U test for continuous data. Univariate and logistic regression were conducted to control for potential known confounders.

RESULTS

There were 419 cases of ASBO with 253 (60.4%) females. The median age of diagnosis was 62 (15-93) years and the median ASA score was 2 (1-4). Forty-nine (11.7%) patients required operative management, the median day-stay was three (1-154) d and 151 (36%) patients were taking statins. On univariate analysis, statin use was associated with decreased operative rates (P = 0.02). The relative risk was 0.46 with an absolute risk reduction of 7.9% (95% CI: 2.1%-13.7%). The number needed to treat was 13 (NNT = 13; 95% CI: 7.3-46.8). Statin use was associated with decreased operative rates using a logistic regression model (P = 0.04).

CONCLUSION

Statin use is independently associated with decreased operative rates in ASBO.