Development of a novel antiadhesive material, alginate flakes, ex vivo and in vivo

Newly Developed Polyglycolic Acid Reinforcement Unified with Sodium Alginate to Prevent Adhesion

Polyglycolic acid (PGA) mesh fabric is widely used for reinforcing injured tissues during surgeries. However, PGA induces chronic inflammation and adhesion. The purpose of this study is to develop PGA reinforcement “without PGA-induced adhesion.” We developed a reinforcement fabric unified with PGA mesh and alginate foam. The antiadhesive effects of sodium alginate foam and calcium alginate foam were evaluated in rats. Sodium alginate foam unified with PGA mesh fabric exhibited strong effects that limit the extent and severity of adhesion, whereas calcium alginate foam unified with PGA mesh was less effective in preventing adhesion. In the sodium alginate group, fibroblasts and collagen fibers around implanted sites were sparse and the material degraded rapidly by macrophage ingestion. Fibroblasts and collagen fibers play a major role in adhesion formation and their excessive proliferation results in postoperative adhesion. Thus, inhibiting their increase is the key in preventing PGA-induced adhesion. The reinforcement that is composed of PGA mesh unified with sodium alginate foam strongly inhibited PGA-induced adhesion and showed excellent handling during surgery and could be easily applied with a one-step procedure.

The Effect of Adjuvant Treatment to Prevent and Treat Intrauterine Adhesions: A Network Meta-Analysis of Randomized Controlled Trials

Intrauterine adhesions (IUAs) can lead to partial or complete closure of the uterine cavity, which may result in symptoms including abnormal menstruation, infertility, and pelvic pain. A network meta-analysis was performed to assess the effect of adjuvant therapy on the prevention and treatment of IUAs. We searched electronic databases, including PubMed, Embase, and the Cochrane Library, up to May 5, 2017, without language restrictions. The primary outcomes in the present analysis were the rate of IUAs for prevention and the rate of IUA recurrence for treatment. The secondary outcomes included the IUA score and the rate of severity of IUAs. The treatments were then ranked by the surface under the cumulative ranking curve (SUCRA). We included 20 articles that involved a total of 1891 patients in our analysis. In the outcomes of prevention-related studies, an alginate hyaluronate-carboxymethylcellulose membrane (ACH) (n = 10, SUCRA score = 93.3%) was the adjuvant treatment that most effectively reduced IUA incidence. It was followed by intercoat (n = 10, SUCRA score = 74.7%) and misoprostol (n = 10, SUCRA score = 68.6%). In addition, auto-cross-linked hyaluronic acid (ACP) (n = 3, SUCRA score = 83.2%) and intercoat (n = 3, SUCRA score = 66.4%) each corresponded to a relatively high preventive effect against severe IUAs. In the treatment-related studies, ACP plus a balloon (n = 4, SUCRA score = 96.3%) and a freeze-dried amnion graft plus a balloon (n = 4, SUCRA score = 62.7%) most effectively reduced IUA recurrence and had a high probability of most effectively reducing IUA scores. Therefore, according to the prophylactic analysis, ACH and intercoat were most likely to prevent IUA development. In our analysis of agents used to prevent severe IUAs, we found that ACP and intercoat provided significant advantages and had high reliability. In our analysis of treatments, ACP plus a balloon and freeze-dried amniotic agents plus a balloon were most likely to reduce IUA recurrence and IUA scores after adhesiolysis.

Prevention of Polyglycolic Acid-Induced Peritoneal Adhesions Using Alginate in a Rat Model

Postoperative intra-abdominal or intrathoracic adhesions sometimes cause significant morbidity. We have designed three types of alginate-based treatments using strongly cross-linked (SL), weakly cross-linked (WL), and non-cross-linked (NL) alginate with calcium gluconate. In rat experiments, we compared the antiadhesive effects of the three types of alginate-based treatments, fibrin glue treatment (a standard treatment), and no treatment against adhesions caused by polyglycolic acid (PGA) mesh (PGA-induced adhesions). The antiadhesive materials were set on the PGA sheet fixed on the parietal peritoneum of the abdomen. Fifty-six days later, the adhesions were evaluated macroscopically by the adhesion scores and microscopically by hematoxylin-eosin staining and immunostaining. We also tested the fibroblast growth on the surface of the antiadhesive materials in vitro. The antiadhesive effects of WL and NL were superior to the no treatment and fibrin glue treatment. A microscopic evaluation confirmed that the PGA sheet was covered by a peritoneal layer constructed of well-differentiated mesothelial cells, and the inflammation was most improved in the NL and WL. The fibroblast growth was inhibited most on the surfaces of the NL and WL. These results suggest that either the WL or NL treatments are suitable for preventing PGA-induced adhesions compared to SL or the conventional treatment.

All the commercially available adhesion barriers have the same effect on adhesion prophylaxis?; A comparison of barrier agents using a newly developed, severe intra-abdominal adhesion model

BACKGROUND

Various types of adhesion barriers are widely used to prevent intra-abdominal adhesion. However, few studies have compared the efficacy of adhesion barriers using the same animal model. The aim of this study was to compare the anti-adhesive effects of various barrier agents using a newly developed, severe adhesion model.

METHODS

A severe adhesion model was established by excision of a 1-cm(2) intra-abdominal wall and application of cyanoacrylate in rat. Eighty male Sprague-Dawley rats (10 weeks old; 370 ± 50 g) were divided randomly into four groups (n = 20 each): the untreated control group, G-group using a hyaluronic acid and sodium carboxymethyl cellulose gel (Guardix-sol®), A-group using 4% icodextrin (Adept®), and S-group using a hyaluronate-carboxymethyl cellulose membrane (Seprafilm®). The effect of each adhesion barrier was evaluated by means of the extent and severity of adhesion, difficulty of adhesiolysis scoring systems, and microscopic grade of fibrosis.

RESULTS

The G-group showed no difference in adhesion score and fibrosis, the A-group demonstrated only a significantly lower fibrosis, and the S-group exhibited a significantly lower adhesion score and lower fibrosis compared with the control group. The S-group had a significantly lower adhesion score and reduced fibrosis compared with the G-group; however, no significant difference in adhesion score and fibrosis was noted with the A-group.

CONCLUSIONS

The membranous barrier Seprafilm® may be effective in the prevention of adhesion in the condition of peritoneal injury combined with foreign material. Adept® showed a tendency of decreasing the severity of adhesion and was effective in the prevention of fibrosis.

A randomized, multi-center, clinical trial to assess the efficacy and safety of alginate carboxymethylcellulose hyaluronic acid compared to carboxymethylcellulose hyaluronic acid to prevent postoperative intrauterine adhesion

STUDY OBJECTIVE

To estimate the efficacy of alginate carboxymethylcellulose hyaluronic acid (ACH) gel to prevent intrauterine adhesions after hysteroscopic surgery in comparison with carboxymethylcellulose hyaluronic acid (CH) gel, which is known as an effective adhesion inhibitor.

DESIGN

Randomized, multicenter, single-blind, clinical trial (Canadian Task Force classification I).

SETTING

Tertiary university hospital.

PATIENTS

One hundred eighty-seven patients with a surgically treatable intrauterine lesion (myomas, polyps, septa, intrauterine adhesion, dysfunctional uterine bleeding).

INTERVENTIONS

Patients were randomized to 2 groups: hysteroscopic surgery plus intrauterine application of ACH or CH.

MEASUREMENTS AND RESULTS

The rate of adhesion formation and the adhesion severity score with type and extent were calculated 4 weeks after surgery. The ACH group had results that were comparable to the CH group in terms of the development of intrauterine adhesions at 4 weeks follow-up. The adhesion severities were not different between the 2 groups. In a subgroup without baseline intrauterine adhesion, the ACH group showed a lower intrauterine adhesion rate than the CH group (p = .016).

CONCLUSIONS

ACH had a comparable efficacy to CH in terms of the adhesion rate and severity. In the case of no baseline intrauterine adhesion, intrauterine application of ACH after hysteroscopic surgery had a lower rate of intrauterine adhesion than application of CH.