Increasing anastomosis safety and preventing abdominal adhesion formation by the use of polypeptides in the rat

In vivo toxicity and biodistribution of intraperitoneal and intravenous poly-L-lysine and poly-L-lysine/poly-L-glutamate in rats

The combination of two differently charged polypeptides, poly-L-lysine (PL) and poly-L-glutamate (PG), has shown excellent postsurgical antiadhesive properties. However, the high molecular, positively charged PL is toxic in high doses, proposed as lysis of red blood cells. This study aims to elucidate the in vivo toxicity and biodistribution of PL and complex bound PLPG comparing intravenous and intraperitoneal administration. Fifty-six Sprague-Dawley rats were used in a model with repeated blood samples within 30 min examining blood gases and blood smears. Similarly, FITC labelled PL were used to track bio distribution and clearance of PL, given as single dose and complex bound to PG after intravenous and intraperitoneal administration. Tissue for histology and immunohistochemistry was collected. Blood gases and blood smears as well as histology points to a toxic effect of high dose PL given intravenously but not after intraperitoneal administration. The toxic effect is exerted through endothelial disruption and subsequent bleeding in the lungs, provoking sanguineous lung edema. FITC-labelled PL experiments reveal a rapid clearance with differences between routes and complex binding. This study advocates a new theory of the toxic effects in vivo of high molecular PL. PLPG complex is safe to use as antiadhesive prevention based on this toxicity study given that PL is always intraperitoneally administered in combination with PG and that the dose is adequate.

Efficacy of bioactive polypeptides on bleeding and intra-abdominal adhesions

BACKGROUND

Perioperative bleeding and postoperative adhesions are two problems encountered in abdominal surgery. Commercial products are available that decrease both bleeding and development of abdominal adhesions, but no products are effective in both situations. The combination of differently charged bioactive polypeptides, administered intraperitoneally, has previously been shown effective in decreasing postoperative adhesions. The present study is a pilot examination of the effects on perioperative bleeding and postoperative adhesions, applying the polypeptide concept.

METHODS

Standardized wounds in the liver and spleen were induced in 52 NMRI mice. The amounts of bleeding and postoperative adhesions were measured after 1 and 7 days, respectively. Separate animals were examined after 8 weeks for long-term healing of the parenchymal wounds.

RESULTS

Both parenchymal bleeding and the extent of adhesions significantly decreased (p = 0.001 and p = 0.029, respectively) as compared to controls. Histology after 8 weeks showed no clear signs of impaired or altered healing.

CONCLUSION

Intraperitoneal administration of differently charged polypeptides significantly decreased postoperative bleeding and postoperative adhesions. Bioactive polypeptides appear promising in the promotion of peritoneal healing and merits further studies.