New directions in the prevention of adhesion in laparoscopic surgery

Prevention of intra-abdominal adhesions using the antiangiogenic COX-2 inhibitor celecoxib

OBJECTIVE

To determine the effects of COX-2 specific inhibitors on postoperative adhesion formation.

SUMMARY AND BACKGROUND DATA

Intra-abdominal adhesions are the major cause of intestinal obstruction and secondary infertility after surgical procedures. Because adhesion synthesis requires angiogenesis, and cyclooxygenase-2 enzyme (COX-2) inhibitors have antiendothelial activity, we tested COX-2 inhibitors in a murine model of intra-abdominal adhesion formation.

METHODS

A silicone patch was secured to the lateral abdominal wall of groups of C57BL/6 mice, followed by cecal abrasion to promote adhesion formation. Beginning on the day of surgery, mice were treated with the selective COX-2 agents, celecoxib or rofecoxib, and the nonspecific COX inhibitors, aspirin, naproxen, ibuprofen, or indomethacin. Animals were treated for 10 days and killed. A second group (celecoxib, rofecoxib, aspirin) was treated for 10 days and observed for an additional 25 days. After treatment, intra-abdominal adhesions were scored using a standard method. The patch was subjected to immunohistochemistry with the endothelial-specific marker, CD31.

RESULTS

Animals treated with selective and nonselective COX-2 inhibitors, except aspirin, had significantly fewer adhesions than control animals. Celecoxib produced a maximal reduction in adhesion formation compared with rofecoxib and the nonselective COX-2 inhibitors at 10 days. After 25 days, celecoxib and rofecoxib, but not aspirin, had fewer adhesions than control mice. Adhesions from mice treated with celecoxib had reduced microvessel density compared with rofecoxib, the nonselective COX inhibitors, and control animals.

CONCLUSIONS

Selective COX-2 inhibitors, in particular celecoxib, provide durable inhibition of intra-abdominal adhesions through an antiangiogenic mechanism.

Evaluation of in vivo biocompatibility and biodegradation of photocrosslinked hyaluronate hydrogels (HADgels)

HADgels are newly developed photocrosslinked hyaluronate hydrogels. They are produced from an aqueous solution of a hyaluronan derivative (HAD) in which cinnamic acid is introduced into the carboxyl moiety of hyaluronan using 3-aminopropanol as a spacer. High-energy ultraviolet irradiation of the HAD solution induces photodimerization of cinnamic acid, resulting in the development of a macromolecular network of each hyaluronan to water-insoluble hydrogels. The biocompatibility and biodegradation of HADgels were evaluated by guinea pig intracutaneous injection testing for up to 28 days. By macroscopic and histological observations, HADgels showed good tissue compatibility and did not induce excess inflammation at the injection sites. Biodegradation of the HADgels clearly depended on the degree of crosslinking at the fixed weight concentrations of HAD (0.5% and 1.0%). In addition, serum analyses showed that the injected guinea pigs did not produce specific antibodies against HADgels. These results indicate that HADgels have preferable biocompatibility and can be used as a new class of injectable, absorbable biomaterial, especially for preventing postsurgical adhesion formations.

Comparison of two laparoscopic treatments for experimentally induced abdominal adhesions in pony foals

OBJECTIVE

To compare laparoscopic dissection with-laparoscopic dissection combined with abdominal instillation of ferric hyaluronate gel for the treatment of experimentally induced adhesions in pony foals.

ANIMALS

12 healthy pony foals.

PROCEDURE

A serosal abrasion method was used to create adhesions at 4 sites on the jejunum (day 0). At day 7 laparoscopy was performed and the adhesions observed in each foal were recorded. In group-1 foals (n = 6), the adhesions were separated laparoscopically (treatment 1). In group-2 foals (n = 6), 300 mL of 0.5% ferric hyaluronate gel was infused into the abdomen after the adhesions were separated laparoscopically (treatment 2). At day 24, terminal laparoscopy was performed and the adhesions observed were recorded. Total number of adhesions within each group was compared between day 7 and 24. Data were analyzed to determine whether an association existed between the number of adhesions on day 24 and treatment type.

RESULTS

At day 24, the number of adhesions was significantly decreased within each group, compared with the number of adhesions at day 7 (group-1 foals, 10 vs 22 adhesions; group-2 foals, 3 vs 20 adhesions). Treatment 1 was associated with a significantly higher number of adhesions at day 24, compared with treatment 2 (odds ratio, 4.54; 95% confidence interval, 1.03 to 23.02).

CONCLUSION AND CLINICAL RELEVANCE

Abdominal instillation of 0.5% ferric hyaluronate gel after laparoscopic dissection was a more effective technique than laparoscopic dissection alone to treat experimentally induced adhesions in pony foals. Laparoscopic adhesiolysis following abdominal surgery in foals is a safe and effective technique.

A blocking antibody to the hyaluronan receptor for endocytosis (HARE) inhibits hyaluronan clearance by perfused liver

Hyaluronan (HA) and chondroitin sulfate clearance from lymph and blood is mediated by the hyaluronan receptor for endocytosis (HARE). The purification and molecular cloning (Zhou, B., Weigel, J. A., Saxena, A., and Weigel, P. H. (2002) Mol. Biol. Cell 13, 2853-2868) of this cell surface receptor were finally achieved after we developed monoclonal antibodies (mAbs) against HARE. There are actually two independent isoreceptors for HA, which in rat are designated the 175-kDa HARE and 300-kDa HARE. Only one mAb (number 174) effectively and completely blocked the specific uptake of 125I-HA at 37 degrees C by rat liver sinusoidal endothelial cells. 125I-HA binding to both the 175-kDa and 300-kDa HARE proteins in a ligand blot assay was almost completely inhibited by <1 microg/ml mAb-174, whereas mouse IgG had little or no effect. MAb-174 also performed very well in Western analysis, indirect fluorescence microscopy, and a variety of immuno-procedures. Immunohistochemistry using mAb-174 localized HARE to the sinusoidal cells of rat liver, spleen, and lymph node. Western analysis using mAb-174 revealed that the sizes of both HARE glycoproteins were the same in these three tissues. 125I-HA was taken up and degraded by excised rat livers that were continuously perfused ex vivo with a recirculating medium. This HA clearance and metabolism by liver, which is a physiological function of HARE, was very effectively blocked by mAb-174 but not by mouse IgG. The results indicate that mAb-174 will be a useful tool to study the functions of HARE and the physiological significance of HA clearance.

Diphenhydramine and hyaluronic acid derivatives reduce adnexal adhesions and prevent tubal obstructions in rats

OBJECTIVE

The purpose of this study is to investigate the effects of diphenhydramine-HCl and Na-hyaluronate derivatives on the development of postoperative peritoneal adhesion and tubal obstruction.

STUDY DESIGN

Forty female rats of Sprague-Dawley type were used in the study. The rats were divided into four groups, each comprising 10 subjects. After all the rats were anaesthetized with 50mg/kg ketamine HCl, their abdomens were opened with a lower midline incision. Injury was induced on the right pelvic peritoneum and on the peritoneal surface of left uterine tube. No additional procedure was applied to the first group. 10 mg/kg diphenhydramine-HCl was given to the second group intravenously. In the third group, 0.25 mg/kg Orthovisc, a Na-hyaluronate derivative was diluted with 2 ml physiological saline and poured into the abdomen. For the fourth group, Seprafilm, a Na-hyaluronate derivative was covered in a layer of 0.7 cm x 3 cm over the left uterine tube. After 14 days, the rats were anaesthetized with ketamine HCl again, and 5 cm(3) blood sample was taken with cardiac puncture. The abdomen was opened with an incision transverse to the upper end of the midline incision, and the presence of adhesions was investigated. Detected adhesions were staged according to the Mazuji classification. Tubal patencies were inspected by injecting methylene blue from the uterine corpus into the lumen using an injector. A piece of abdominal wall of 4 cm x 4 cm was removed by extending the incision in the reverse U shape. The tensile strength and bursting pressure of the suture line were determined using the Peacock method. One gram of tissue was taken from the incision line, and hydroxyproline levels were determined by the Bergman-Loxley method. Aspartate aminotransferase (AST) levels were measured.

RESULTS

All of the rats completed the study. AST levels, tissue hydroxyproline levels and tensile strength and bursting pressure test results were found to be similar in all groups. While adhesion rates in the groups were 100, 40, 40 and 30%, respectively, adhesion stages were found to be, respectively as 2.1+/-1.7, 0.6+/-0.67, 0.6+/-0.67 and 0.5+/-0.85. Adhesion stages in the study groups were significantly lower (P<0.05). Tubal obstruction rates were found to be 70, 30, 30 and 20%, respectively.

CONCLUSION

Diphenhydramine, Orthovisc and Seprafilm significantly reduce postoperative peritoneal adhesion development, and they allow the uterine tubes to remain open.

Evaluation of laparoscopic adhesiolysis for the treatment of experimentally induced adhesions in pony foals

OBJECTIVE

To assess the efficacy of laparoscopic adhesiolysis in the treatment of experimentally induced adhesions in foals.

ANIMALS

8 healthy pony foals.

PROCEDURE

Celiotomy was performed and adhesions created at the jejunoileal junction and at sites 0.5 and 1 m proximal to this junction, using a serosal abrasion method. Ten days after celiotomy, exploratory laparoscopy was performed. Laparoscopic adhesiolysis was performed in the treatment group only (4 foals, randomly selected). Thirty days after the exploratory laparoscopy, a final laparoscopic examination was performed, and the foals were euthanatized. The number and characteristics of abdominal adhesions were recorded during laparoscopy 10 and 30 days after celiotomy and during necropsy.

RESULTS

At 30 days after celiotomy, the number of adhesions in the control group was significantly higher than the number in the treatment group. In the control group, all adhesions observed during the exploratory laparoscopy were still evident at the final laparoscopy and necropsy. In the treatment group, adhesions did not form again after separation. During final laparoscopy and necropsy, a focal adhesion between the omentum and site of the initial laparoscope portal was observed in 5 of 8 foals.

CONCLUSIONS AND CLINICAL RELEVANCE

The serosal abrasion model is useful for studying abdominal adhesions in foals. Laparoscopic adhesiolysis was an effective technique to break down experimentally induced adhesions in the early maturation stage of formation in pony foals. Studies are required to investigate prevention of de novo adhesions at the laparoscope portal sites.

Surgical management of adhesions, endometriosis, and tubal pathology in the woman with infertility

There are many considerations in the surgical treatment of patients with infertility. Of prime importance is the baseline condition of the tubes and skill of the surgeon. With further advances in the understanding of the process of fertilization and implantation, it is anticipated that the use of surgical methods and application of new technologies will continue to improve fecundity for patients with infertility.