Prevention of Intraabdominal Adhesions: An Experimental Study Using Mitomycin-C and 4% Icodextrin

Piperine Liposome-Embedded in Hyaluronan Hydrogel as an Effective Platform for Prevention of Postoperative Peritoneal Adhesion

This study aimed to prepare piperine (PIP) loaded liposomes in hyaluronic acid (HA) hydrogel to provide a hybrid superstructure for postoperative adhesion prevention. Liposomes were prepared using thin-film hydration method. The optimised formulation was characterised by size, SEM, TEM, FTIR, encapsulation efficiency (EE)% (w/w), and release pattern. Liposome-in-hydrogel formulation was investigated by rheology, SEM, and release studies. The efficacy was evaluated in a rat peritoneal abrasion model. EE% (w/w) increased with increasing lipid concentration from 10 to 30; however, a higher percentage of Chol reduced EE% (w/w). The optimised liposome (EE: 68.10 ± 4.18% (w/w), average diameter: 513 ± 14.67 nm, PDI: 0.15 ± 0.04) was used for hydrogel embedding. No sign of adhesion in 5/8 rats and no collagen deposition confirmed the in vivo effectiveness of the optimised formulation. Overall, providing a sustained delivery of PIP, the developed liposome-in-hydrogel formulation can be a promising carrier to prevent postoperative adhesion.

Experimental evaluation of icodextrin delivery as pressurized aerosol (PIPAC): Antiadhesive and cytotoxic effects

BACKGROUND

Icodextrin (IDX) is an antiadhesive polymer that can be used as a carrier solution for intraperitoneal (IP) delivery of chemotherapeutic drugs.

METHODS

We investigated the suitability of IDX solution as a carrier of Cisplatin and Doxorubicin for delivery as pressurized intraperitoneal aerosol chemotherapy (PIPAC). We examined the sprayability of IDX, the aerosol characteristics, the stability of the molecule after aerosolization, the effects of IDX on the adhesion of MKN45 human gastric cancer cells, the synergistic effect of aerosolized IDX with Cisplatin and Doxorubicin, and the chemical stability of IDX, Cisplatin, and Doxorubicin in combination.

RESULTS

Delivery of IDX as PIPAC is feasible with no particular restrictions. The median droplet size of 35.7 μm did not change at increasing concentrations. IDX withstood the shear forces applied by the nebulizer and remained stable after aerosolization (ANOVA, p = 0.97). IDX did not impair the cytotoxic effects of Cisplatin and Doxorubicin (ns). IDX had a significant antiadhesive impact alone (p < 0.03) and in combination with Cisplatin and Doxorubicin (p < 0.02). IDX as a carrier for Cisplatin and Doxorubicin remained stable at 4 °C for three months and did not cause degradation of those two substances.

CONCLUSION

The proposed combination takes advantage of the antiadhesive properties of IDX, the cytotoxic effect of Cisplatin and Doxorubicin, and an advanced drug delivery system.

Rosemary oil nano-emulsion potentiates the apoptotic effect of mitomycin C on cancer cells in vitro

Purpose: To formulate nano-emulsified rosemary oil (REO/NE) and determine its effect on the anticancer agent, mitomycin C (MC) when used as a carrier for the drug.

Methods: The droplet size of REO/NE was markedly enlarged when mixed with MC. The cytotoxicity of the formulations on HeLa and MCF-7 cells was determined using MTT assay. The combination index (CI) values were estimated with CompuSyn software, while apoptosis was determined using DAPI fluorescent dye.

Results: Treatment of MCF-7 cells and HeLa cells with REO/NE (1% v:v and 1.33% v:v, respectively) reduced the IC50 of MC 33 and 15 folds, respectively. Under fluorescent microscopy, cells treated with REO/NE+MC had more marked reduction of the nuclear area than MC-treated cells.

Conclusion: These results indicate that REO/NE is an efficient carrier for MC since it enhanced MC delivery and increased its effect on the cells through the induction of apoptosis at low concentrations of MC.

Advancement of Biomaterial-Based Postoperative Adhesion Barriers

Postoperative peritoneal adhesion (PPA) is a prevalent incidence that generally happens during the healing process of traumatized tissues. It causes multiple severe complications such as intestinal obstruction, chronic abdominal pain, and female infertility. To prevent PPA, several antiadhesion materials and drug delivery systems composed of biomaterials are used clinically, and clinical antiadhesive is one of the important applications nowadays. In addition to several commercially available materials, like film, spray, injectable hydrogel, powder, or solution type have been energetically studied based on natural and synthetic biomaterials such as alginate, hyaluronan, cellulose, starch, chondroitin sulfate, polyethylene glycol, polylactic acid, etc. Moreover, many kinds of animal adhesion models, such as cecum abrasion models and unitary horn models, are developed to evaluate new materials' efficacy. A new animal adhesion model based on hepatectomy and conventional animal adhesion models is recently developed and a new adhesion barrier by this new model is also developed. In summary, many kinds of materials and animal models are studied; thus, it is quite important to overview this field's current progress. Here, PPA is reviewed in terms of the species of biomaterials and animal models and several problems to be solved to develop better antiadhesion materials in the future are discussed.

Peritoneal adhesions: Occurrence, prevention and experimental models

Peritoneal adhesions (PA) are a postoperative syndrome with high incidence rate, which can cause chronic abdominal pain, intestinal obstruction, and female infertility. Previous studies have identified that PA are caused by a disordered feedback of blood coagulation, inflammation, and fibrinolysis. Monocytes, macrophages, fibroblasts, and mesothelial cells are involved in this process, and secreted signaling molecules, such as tumor necrosis factor alpha (TNF-α), interleukin-10 (IL-10), tissue plasminogen activator (tPA), and type 1 plasminogen activator inhibitor (PAI-1), play a key role in PA development. There have been many attempts to prevent PA formation by anti-PA drugs, barriers, and other therapeutic methods, but their effectiveness has not been widely accepted. Treatment by biomaterial-based barriers is believed to be the most promising method to prevent PA formation in recent years. In this review, the pathogenesis, treatment approaches, and animal models of PA are summarized and discussed to understand the challenges faced in the biomaterial-based anti-PA treatments.

Postoperative peritoneal adhesion: an update on physiopathology and novel traditional herbal and modern medical therapeutics

Postoperative peritoneal adhesion (PPA) is a serious clinical condition that affects the high percentage of patients after abdominal surgery. In this review, we have tried to focus on pathophysiology and different underlying signal pathways of adhesion formation based on recent progress in the molecular and cellular mechanisms. Also, the strategies, developed based on traditional herbal and modern medicines, to prevent and treat the PPA via regulation of the molecular mechanisms were investigated. The search engines such as Google Scholar, PubMed, Scopus, and Science Direct have been used to evaluate the current literature related to the pathogenesis of adhesion formation and novel products. Recently, different mechanisms have been defined for adhesion formation, mainly categorized in fibrin formation and adhesion fibroblast function, inflammation, and angiogenesis. Therefore, the suppression of these mechanisms via traditional and modern medicine has been suggested in several studies. While different strategies with encouraging findings have been developed, most of the studies showed contradictory results and were performed on animals. The herbal products have been introduced as safe and effective agent which can be considered in future preclinical and clinical studies. Although a wide range of therapeutics based on traditional and modern medicines have been suggested, there is no agreement in the efficacy of these methods to prevent or treat adhesion formation after surgeries. Further basic and clinical researches are still needed to propose the efficiency of recommended strategies for prevention and treatment of PPA.

Controlled release of Mitomycin C from modified cellulose based thermo-gel prevents post-operative de novo peritoneal adhesion

The complications from surgery associated peritoneal adhesion can be alleviated by combination of physical isolation and pharmaceutical treatment. This work aims to develop thermo-sensitive hydrogel barrier by combining mitomycin C (MMC) with modified tempo oxidized nanocellulose (cTOCN) through EDC/NHS-chemical conjugation followed by integration with methyl cellulose (MC). The MMC was successfully combined with cTOCN and ensured controlled release of MMC from hydrogel throughout 14 days. Amount of MC (1.5, 2.5, 3.5% w/v) was proportional to gelation time and inversely proportional to degradation of hydrogel. The optimized hydrogel (C2.5T1M0.2) needed only 30 s for thermoreversible sol-gel (4℃-37℃) phenomenon and did not show in vitro fibroblast cells toxicity as well as ensured complete adhesion prevention efficacy, reperitonealization in rat side wall-cecal abrasion model. Overall, the developed C2.5T1M0.2 thermo-gel advances state-of-the-art in view of cytocompatibility, mechanical stability, optimum degradation, good injectability, sustain drug release from surgical sites, and satisfactory de novo anti-adhesion capacity.

Crystalloid fluid suspension results in decreased adhesion burden when compared to bioresorbable membranes in a rat model

INTRODUCTION

Adhesion formation represents a major cause of long-term morbidity. Suspension of intra-abdominal contents in fluid medium may effectively prevent adhesion formation. We compare saline hydro-flotation (NS) to hyaluronate bioresorbable membranes (HBM) for adhesion prevention following surgery.

METHODS

Animals were randomized to four groups: sham (no injury, n = 5), control (injury without intervention, n = 5), HBM (n = 20) or 10 cc NS (n = 21). Interventions were administered after standardized surgical trauma to the cecum and abdominal wall. Necropsies at two weeks were completed to compare adhesion burden using a customary scoring algorithm.

RESULTS

Significant adhesion burden was noted in all rats. HBM sustained a more significant adhesion burden with higher total adhesion scores (HBM = 10 vs NS = 8.1/15, p = 0.02). Gross adhesion scores were lower with NS (5.6/9) compared to HBM (7.1/9, p = 0.01). Neo-vascularity was more common in HBM at 2.6/3 versus 1.9/3 with NS (p = 0.01). Percent of the cecum encased with adhesion was higher with HBM (42%) compared to NS (31%, p = 0.05).

DISCUSSION

Fluid based anti-adhesion methods should be considered for abdominal adhesion formation prevention.

The sticky business of adhesion prevention in minimally invasive gynecologic surgery

PURPOSE OF REVIEW

The negative impact of postoperative adhesions has long been recognized, but available options for prevention remain limited. Minimally invasive surgery is associated with decreased adhesion formation due to meticulous dissection with gentile tissue handling, improved hemostasis, and limiting exposure to reactive foreign material; however, there is conflicting evidence on the clinical significance of adhesion-related disease when compared to open surgery. Laparoscopic surgery does not guarantee the prevention of adhesions because longer operative times and high insufflation pressure can promote adhesion formation. Adhesion barriers have been available since the 1980s, but uptake among surgeons remains low and there is no clear evidence that they reduce clinically significant outcomes such as chronic pain or infertility. In this article, we review the ongoing magnitude of adhesion-related complications in gynecologic surgery, currently available interventions and new research toward more effective adhesion prevention.

RECENT FINDINGS

Recent literature provides updated epidemiologic data and estimates of healthcare costs associated with adhesion-related complications. There have been important advances in our understanding of normal peritoneal healing and the pathophysiology of adhesions. Adhesion barriers continue to be tested for safety and effectiveness and new agents have shown promise in clinical studies. Finally, there are many experimental studies of new materials and pharmacologic and biologic prevention agents.

SUMMARY

There is great interest in new adhesion prevention technologies, but new agents are unlikely to be available for clinical use for many years. High-quality effectiveness and outcomes-related research is still needed.

Human-Derived Amniotic Membrane Is Associated With Decreased Postoperative Intraperitoneal Adhesions in a Rat Model

BACKGROUND

Complications from adhesions after intra-abdominal surgery accounts for ~6% of hospital admissions. Currently, hyaluronate/carboxymethylcellulose represents the main option to prevent postoperative adhesion formation. Human amniotic membrane contains inherent anti-inflammatory properties that mitigate adhesion formation.

OBJECTIVE

This study aimed to evaluate adhesion generation after surgical trauma with amniotic membranes compared with standard intraperitoneal adhesion barriers.

DESIGN

This study is a double-blinded, prospective evaluation.

SETTING

This study was conducted at an animal research facility.

ANIMALS

Forty male rats were studied.

INTERVENTION

Laparotomy was performed with peritoneal disruption to the cecum. Animals were randomly assigned to 1 of 5 groups: sham, control, saline, hyaluronic acid membrane, or amniotic membrane. Animals were euthanized at 14 days.

MAIN OUTCOME MEASURES

Independent gross and histological assessments of adhesions were analyzed between groups by using adhesion scoring and microscopy. Scoring was based on the percentage of the cecum involved (0-4), vascularity of adhesions (0-3), strength (0-3), inflammation (0-3), and fibrosis (0-3). Adhered tissue was harvested for polymerase chain reaction analysis for gene regulation activity.

RESULTS

All rats survived 14 days. Adhesions were observed in all animals. There were significantly fewer adhesions in the amniotic membrane group (2) versus hyaluronic acid (3) group (p = 0.01). The percentage of adhesion to the cecum was lower in the amniotic membrane group (29%) than in the hyaluronic acid group (47%, p = 0.04). Histological examination showed no significant difference between or within the 3 groups for inflammation or fibrosis. Genetic analysis of adhered tissues supported high rates of epithelialization and inhibition of fibrosis in the amniotic membrane group.

LIMITATIONS

We are limited by the small sample size and the preclinical nature of the study.

CONCLUSION

Human-derived amniotic membrane is effective at reducing intraperitoneal adhesion after surgical trauma and is superior to the current antiadhesion barriers. Amniotic membranes are well absorbed and demonstrate short-term safety. See Video Abstract at http://links.lww.com/DCR/A554.