The Efficacy of an Ultrapure Alginate Gel in Reducing Adhesion Formation in a Rat Model of Blood Contamination.

BACKGROUND: Formation of peritoneal adhesions is the most frequent complication of abdominal and pelvic surgery and comprises a lifelong risk of adhesion-related morbidity and mortality. Some of the existing antiadhesive barriers are less effective in the presence of blood. In this study, we investigate the efficacy and safety of ultrapure alginate gel in the presence of blood. METHODS: In experiment 1 (30 rats), 1 mL ultrapure alginate gel was compared with no intervention in a model of cecal abrasion and persisting peritoneal bleeding by incision of the epigastric artery. In experiment 2 (30 rats), 2 mL ultrapure alginate gel was compared with no intervention in a model where a 1 mL blood clot was instilled intra-abdominally and a cecal resection was performed. The primary endpoint was the incidence and severity of adhesions after 14 d. RESULTS: In experiment 1, seven of 15 rats in the experimental group had intra-abdominal adhesions compared with 13 of 15 rats in the control group (P = 0.05); 3 of 15 rats had adhesions at the site of injury compared with 12 of 15 rats in the control group (P < 0.01). The severity and extent of adhesions was also reduced (P < 0.01). In experiment 2, 12 of 13 rats had adhesions compared with 13 of 14 rats in the control group (P = 1.00). CONCLUSIONS: Ultrapure alginate gel reduces the incidence and severity of adhesion in the presence of persisting bleeding, but not in a model of cecal resection and blood clot.

Safety and Efficacy of Alginate Adhesion Barrier Gel in Compromised Intestinal Anastomosis.

BACKGROUND: For any anti-adhesive barrier developed for abdominal surgery, the use under conditions in which anastomotic healing is compromised needs to be investigated. The current study evaluates the effect of a new ultrapure alginate gel on early healing of high-risk anastomoses in the ileum and compares this with the gold standard used in clinical practice. MATERIALS AND METHODS: In 75 adult male Wistar rats, a 5 mm ileal segment was resected and continuity was restored by construction of an inverted anastomosis. Rats were divided randomly into a control group and groups receiving either alginate gel or a sodium hyaluronate carboxymethylcellulose (HA/CMC) film around the anastomosis (n = 25 each). Carprofen, given in a daily dose of 1.25 mg/kg, was used to compromise anastomotic healing. At day three, animals were killed and scored for signs of anastomotic leakage and the presence of adhesions. RESULTS: The incidence of adhesion formation was 95% in the HA/CMC film group, which was significantly higher than in the controls (64%, p = 0.010) and the alginate gel group (52%, p = 0.004). The adhesion score was nearly 40% lower in the alginate gel group compared with the HA/CMC film group. The incidence of ileal leakage in the HA/CMC film group (92%) was significantly higher than in the controls (68%, p = 0.016). Leakage rate did not differ between the alginate gel and control groups. There was no significant difference between groups in either incision bursting pressure or incision breaking strength. CONCLUSION: Ultrapure alginate gel does not interfere with repair of ileal anastomoses constructed under conditions in which chances of anastomotic dehiscence are high. The alginate gel performs better than the HA/CMC film.

Efficacy and Safety of Ultrapure Alginate-Based Anti-Adhesion Gel in Experimental Peritonitis.

BACKGROUND: Intra-abdominal infection may lead to adhesion and abscess formation. An adhesion barrier can reduce these complications but also aggravate intra-peritoneal infection, causing the opposite effects. The fear of infection propagation has limited clinical adhesion barrier use in a contaminated or infected abdomen. This study evaluated both adhesion and abscess reduction and infection propagation of a new ultrapure alginate-based anti-adhesive barrier gel in a rat peritonitis model. METHODS: In 64 male Wistar rats, bacterial peritonitis was induced via intra-abdominal injection of a mixture of sterile feces, 10(5) colony-forming units (CFU) of Escherichia coli, and 10(4) CFU of Bacteroides fragilis. Surgical debridement and peritoneal lavage were performed 1 h after inoculation. Animals were randomly allocated in equal numbers to a control group or an alginate gel group. Animals were sacrificed on day five post-operatively. Death and the presence and size of intra-abdominal abscesses were noted, and adhesions were scored. All outcomes were compared in the two groups. RESULTS: Seventeen rats (27%) died prematurely without any difference between the groups. Of the surviving rats in the alginate gel group, 88% developed abscesses vs. 100% of the control group. There was no significant difference in the abscess scores or incidence rates of adhesion formation between the groups. The adhesion scores were lower for the alginate gel group compared with control animals (p=0.04). CONCLUSION: Ultrapure alginate gel reduces adhesion severity but not abscesses. The gel seemed to be safe, not aggravating intra-peritoneal infection in this abdominal infection model.

Ultrapure alginate gel reduces adhesion reformation after adhesiolysis.

PURPOSE: Adhesiolysis at repeat surgery induces adhesion reformation which seems more virulent than development of de novo adhesions. We studied the effect of a new ultrapure alginate gel on adhesion reformation. METHODS: In 46 male Wistar rats, adhesion formation was induced using the cecal abrasion and peritoneal sidewall excision procedure. Two weeks later, a second laparotomy was performed, adhesions were graded, and surgical adhesiolysis was performed. The animals were then allocated to one of two equal groups, a control group without further intervention and a group receiving 1-ml ultrapure alginate gel to the two opposing and damaged surfaces. Two weeks after the second surgery, rats were sacrificed. Primary endpoint was the incidence of adhesion reformation at areas of injury. Secondary endpoints were adhesion scores, extent of adhesions, and tissue histology. RESULTS: Ultrapure alginate gel significantly (p = 0.046) reduced the incidence of adhesion reformation from 100 % in controls to 78 % in experimental rats. Both the adhesion score (p = 0.009) and the extent of adhesions (p = 0.001) were significantly lower in the alginate group. Tissue healing histology was similar in both groups. CONCLUSION: Ultrapure alginate gel reduces adhesion reformation following adhesiolysis.

Ultrapure alginate anti-adhesion gel does not impair colon anastomotic strength.

BACKGROUND: Ultrapure alginate gel is promising in terms of adhesion prevention. Because anti-adhesive barriers have been shown to disturb healing of bowel anastomoses, the effect of ultrapure alginate gel on the repair of colon anastomoses was studied. MATERIALS AND METHODS: In 102 male Wistar rats, a 0.5-cm segment was resected from the descending colon and continuity was restored by an inverted single-layer end-to-end anastomosis. Animals were randomized into a control, an alginate gel, and a sodium hyaluronate carboxymethyl cellulose film group, each n = 34. Half of each group was sacrificed at day 3 and 7 postoperatively. Anastomotic strength was assessed by measuring both bursting pressure and breaking strength. Hydroxyproline content was measured and histologic analysis was performed. The incidence of adhesion and abscess formation was scored at sacrifice. RESULTS: No difference in either anastomotic-bursting pressure or breaking strength was found between experimental groups and the controls at any time point. Both the incidence of adhesion formation (35% versus 71%, P = 0.007) and the adhesion score (0.38 versus 0.79, P = 0.009) were significantly lower in the alginate gel group than in the controls. The abscess rate was higher (46% versus 18%, P = 0.030) in the hyaluronate carboxymethyl cellulose group than in the controls and unchanged in the alginate gel group. CONCLUSIONS: While reducing adhesion formation, ultrapure alginate gel does not interfere with the development of colonic anastomotic strength during the crucial early healing period.