Antiadhesion effects of docosahexaenoic acid on normal human peritoneal and adhesion fibroblasts

Docosahexaenoic Acid-Infused Core-Shell Fibrous Membranes for Prevention of Epidural Adhesions

Avoiding epidural adhesion following spinal surgery can reduce clinical discomfort and complications. As the severity of epidural adhesion is positively correlated with the inflammatory response, implanting a fibrous membrane after spinal surgery, which can act as a physical barrier to prevent adhesion formation while simultaneously modulates postoperative inflammation, is a promising approach to meet clinical needs. Toward this end, we fabricated an electrospun core-shell fibrous membrane (CSFM) based on polylactic acid (PLA) and infused the fiber core region with the potent natural anti-inflammatory compound docosahexaenoic acid (DHA). The PLA/DHA CSFM can continuously deliver DHA for up to 36 days in vitro and reduce the penetration and attachment of fibroblasts. The released DHA can downregulate the gene expression of inflammatory markers (IL-6, IL-1β, and TNF-α) in fibroblasts. Following an in vivo study that implanted a CSFM in rats subjected to lumbar laminectomy, the von Frey withdrawal test indicates the PLA/DHA CSFM treatment can successfully alleviate neuropathic pain-like behaviors in the treated rats, showing 3.60 ± 0.49 g threshold weight in comparison with 1.80 ± 0.75 g for the PLA CSFM treatment and 0.57 ± 0.37 g for the untreated control on day 21 post-implantation. The histological analysis also indicates that the PLA/DHA CSFM can significantly reduce proinflammatory cytokine (TNF-α and IL-1β) protein expression at the lesion and provide anti-adhesion effects, indicating its vital role in preventing epidural fibrosis by mitigating the inflammatory response.

Docosahexaenoic Acid Promotes Eryptosis and Haemolysis through Oxidative Stress/Calcium/Rac1 GTPase Signalling

Docosahexaenoic acid (DHA) is an omega-3 polyunsaturated fatty acid with promising anticancer potential. Anaemia is a frequent adverse effect of anticancer treatment caused in part by eryptosis and haemolysis. Thus, it is important to investigate the role of DHA in red blood cell (RBC) death. RBCs were treated with anticancer concentrations (10-100 μM) of DHA under different physiological conditions, and fluorescence-assisted cell sorting was employed to measure eryptotic markers. Cell membrane scrambling was detected by annexin-V-FITC labelling, cytoplasmic Ca2+ by Fluo4/AM, cell size by forward scatter (FSC), and oxidative stress by H2DCFDA. Haemolytic markers were also assayed by photometric methods. DHA caused significant phospholipid scrambling with Ca2+ accumulation, loss of cellular volume, and oxidative stress. These changes were associated with dacrocyte formation, as revealed by electron microscopy. Moreover, DHA exhibited a dual effect on membrane integrity: it was haemolytic under isotonic conditions and anti-haemolytic in hypotonic environments. Importantly, inhibition of Rac1 GTPase activity with NSC23766 significantly reduced DHA-mediated haemolysis, as did co-administration of either sucrose or polyethylene glycol 8,000. Conversely, the presence of 125 mM KCl and urea without extracellular Ca2+ significantly exacerbated DHA toxicity. In conclusion, this is the first report that identifies key biochemical mechanisms underlying the cytotoxic effects of DHA in RBCs, promoting further development and validation of DHA in anticancer therapy.

The preventive effect of omega-3 fish oil on the formation of peritoneal adhesions

<br><b>Introduction:</b> Postoperative peritoneal adhesions that form after abdominal surgery still continue to exist as an unresolved health problem.</br> <br><b>Aim:</b> The aim of the study is to examine whether omega-3 fish oil has a preventive effect on postoperative peritoneal adhesions.</br> <br><b>Material and methods:</b> Twenty-one female Wistar albino rats were separated into 3 groups (sham, control and experimental), each consisting of 7 rats. In the sham group, only laparotomy was performed. In both the control and experimental group rats, the right parietal peritoneum and cecum were traumatised to form petechiae. Following this procedure, the abdomen was irrigated with omega-3 fish oil in the experimental group. The rats were re-explored on the 14^th postoperative day and any adhesions were scored. Tissue samples and blood samples were taken for histopathological and biochemical analysis.</br> <br><b>Results:</b> None of the rats that were administered omega-3 fish oil developed macroscopic postoperative peritoneal adhesions (P = 0.005). The omega-3 fish oil formed an anti-adhesive lipid barrier on the injured tissue surfaces. Microscopic evaluation revealed diffuse inflammation with excessive connective tissue and fibroblastic activity in the control group rats, while foreign body reactions were common in the omega-3 rats. The mean amount of hydroxyproline in samples from injured tissues was significantly lower in the omega-3 rats than in the control rats (P = 0.004).</br> <br><b>Conclusion:</b> Intraperitoneal application of omega-3 fish oil prevents postoperative peritoneal adhesions by forming an anti-adhesive lipid barrier on injured tissue surfaces. However, further studies are needed to determine whether this adipose layer is permanent or will be resorbed over time.</br>.

Combination therapy with butyrate and docosahexaenoic acid for keloid fibrogenesis: an in vitro study

Background:

A single, effective therapeutic regimen for keloids has not been established yet, and the development of novel therapeutic approaches is expected. Butyrate, a short-chain fatty acid, and docosahexaenoic acid (DHA), a ω-3 polyunsaturated fatty acid, play multiple anti-inflammatory and anticancer roles via their respective mechanisms of action.

Objective:

In this study, we evaluated the antifibrogenic effects of their single and combined use on keloid fibroblasts.

Methods:

Keloid fibroblasts were treated with butyrate (0-16 mM) and/or DHA (0-100 µM) for 48 or 96 h.

Results:

Butyrate inhibited cell proliferation, and α-smooth muscle actin (α-SMA) and type III collagen expressions, with inhibition of the transforming growth factor (TGF)-β1 and TGF-β type I receptor expressions and increased prostaglandin E2 with upregulation of cyclooxygenase-1 expression with induction of histone acetylation. DHA inhibited α-SMA, type III collagen, and TGF-β type I receptor expressions. Then, the butyrate/DHA combination augmented the antifibrogenic effects, resulting in additional inhibition of α-SMA, type I and III collagen expressions, with strong disruption of stress fiber and apoptosis induction. Moreover, the butyrate/DHA combination inhibited the cyclooxygenase-2 expression, suggesting stronger anti-inflammatory effect than each monotherapy.

Study limitations:

Activation in keloid tissue is affected not only by fibroblasts but also by epithelial cells and immune cells. Evaluation of the effects by butyrate and DHA in these cells or in an in vivo study is required.

Conclusion:

This study demonstrated that butyrate and docosahexaenoic acid have antifibrogenic effects on keloid fibroblasts and that these may exert therapeutic effects for keloid.

Advances in the Pathogenesis of Adhesion Development: The Role of Oxidative Stress

Over the past several years, there has been increasing recognition that pathogenesis of adhesion development includes significant contributions of hypoxia induced at the site of surgery, the resulting oxidative stress, and the subsequent free radical production. Mitochondrial dysfunction generated by surgically induced tissue hypoxia and inflammation can lead to the production of reactive oxygen and nitrogen species as well as antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase which when optimal have the potential to abrogate mitochondrial dysfunction and oxidative stress, preventing the cascade of events leading to the development of adhesions in injured peritoneum. There is a significant cross talk between the several processes leading to whether or not adhesions would eventually develop. Several of these processes present avenues for the development of measures that can help in abrogating adhesion formation or reformation after intraabdominal surgery.

Lycopene, a powerful antioxidant, significantly reduces the development of the adhesion phenotype

Postoperative adhesions are a common medical complication of gynecologic and other pelvic surgeries resulting in persistent pelvic pain, obstruction of the intestines, and even infertility. The molecular mechanisms of postoperative adhesion development remain to be elucidated. We have recently described a role for reactive oxygen species, specifically superoxide, in the development of postoperative adhesions. In this study, we sought to determine whether lycopene, a potent antioxidant, reduces markers characteristic of the adhesion phenotype. Primary fibroblast cultures from normal peritoneum and adhesion tissues were utilized to determine mRNA levels of adhesion phenotype markers type I collagen, transforming growth factor-beta 1 (TGF-β1), and vascular endothelial growth factor (VEGF) in response to lycopene (24 hours, 10 μM) treatment. There was a 2 (p < 0.003), 4.7 (p < 0.004), and 1.6 fold (p < 0.004) increase in mRNA levels of type I collagen, TGF-β1, and VEGF, respectively, in adhesion as compared to normal peritoneal fibroblasts. Lycopene treatment led to a 6.8 and a 12.4 fold decrease in type I collagen mRNA levels, in normal peritoneal and adhesion fibroblasts, respectively (p < 0.005). Lycopene treatment led to a 4.2 (p < 0.03) and a 4.6 (p < 0.05) fold decrease in VEGF mRNA levels, in normal peritoneal and adhesion fibroblasts, respectively. Lycopene treatment led to a 7.0 fold decrease in TGF-β1 mRNA levels, in adhesion fibroblasts (p < 0.03). A 1.9 fold decrease in TGF-β1 mRNA was observed in normal peritoneal fibroblasts in response to treatment, although it was not significant. Lycopene substantially reduced levels of adhesion phenotype markers in normal peritoneal and adhesion fibroblasts and whether it will reduce postoperative adhesions needs to be further investigated.

Adhesion-preventing properties of 4% icodextrin and canola oil: a comparative experimental study

OBJECTIVE

Postsurgical abdominal adhesions are common, serious postoperative complications. The present study compared the usefulness of 4% icodextrin and canola oil in preventing postoperative peritoneal adhesions.

METHODS

Twenty-four Wistar albino rats were divided into three groups. Following a laparotomy, a serosal abrasion was made by brushing the cecum, and 3 mL of 0.9% NaCl, 4% icodextrin, or 3 mL of canola oil were intraperitoneally administered for the control, icodextrin, and canola oil groups, respectively. The abdomen was then closed. All of the rats were sacrificed at day 10. Macroscopic, histopathological, and biochemical evaluations were performed. The results were statistically analyzed using Kruskal-Wallis and ANOVA tests.

RESULTS

Macroscopic analyses revealed that both canola oil and 4% icodextrin reduced adhesion formation, but the difference was not statistically significant (p = 0.17). The histopathological examinations revealed no significant differences in terms of giant cell, lymphocyte/plasmocyte, neutrophil, ICAM1, or PECAM1 scores. However, both canola oil and 4% icodextrin significantly reduced fibrosis (p = 0.025). In the canola oil group, the histiocytic reactions were significantly increased (p = 0.001), and the hydroxyproline levels were significantly lower than those in the other groups (p = 0.034).

CONCLUSIONS

In the present study, canola oil was determined to be superior to 4% icodextrin in lowering hydroxyproline levels and increasing histiocytic reactions. Considering these results, we believe that canola oil is a promising agent for preventing adhesion formation.

Dietary fish oil supplementation inhibits formation of endometriosis-associated adhesions in a chimeric mouse model

OBJECTIVE

To examine whether dietary fish oil supplementation reduces development of spontaneous endometriosis-associated adhesions using an established model.

DESIGN

Laboratory-based study.

SETTING

Medical center research laboratory. PATIENT(S)/ANIMAL(S): Disease-free women of reproductive age and nude mice.

INTERVENTION(S)

Women were not provided any intervention. Mice were randomized to receive fish oil supplementation or control diet.

MAIN OUTCOME MEASURE(S)

Experimental endometriosis was established in mice via injection of human endometrial tissue within 16 hours of ovariectomy. Mice were provided standard or menhaden fish oil-supplemented diets for ≥ 2 weeks before initiation of experimental endometriosis and until killing them 1 week later. At necropsy, mice were examined for the presence and extent of adhesions and endometriotic-like lesions. Tissues were excised and morphologically characterized.

RESULT(S)

Adhesions/lesions were reduced in mice provided with dietary fish oil compared with control animals. Leukocytes were more numerous within the adhesions/lesions of the mice maintained on the standard diet compared with animals provided with fish oil. As indicated by staining intensity, collagen deposition was greater at adhesion sites within control mice compared with fish oil-supplemented animals.

CONCLUSION(S)

Wound-healing associated with surgery created an inflammatory peritoneal microenvironment that promoted the development of both experimental endometriosis and adhesions in a murine model. Targeting excessive inflammation with fish oil may be an effective adjuvant therapy to reduce the development of postsurgical adhesions related to endometriosis.

Comparison of 4 % icodextrin and omega 3 Fatty acids in prevention of peritoneal adhesions

Postoperative peritoneal adhesions are major concerns in abdominal surgery. In this experimental study, the effects of 4 % icodextrin and omega-3 fatty acids (ω-3 FA) on prevention of postoperative peritoneal adhesions were evaluated. Twenty-four Wistar albino rats were divided into three groups. After laparotomy, serosal abrasion was carried out by cecal brushing. Intraperitoneally 3 cm(3) 0.9 % NaCl, 3 cm(3) 4 % icodextrin, and 200 mg/kg ω-3 FAs for each group were applied, and then the abdomen was closed. All subjects sacrificed 10 days postoperatively. Macroscopic and histopathological cellular reactions as a function of giant cell, lymphocyte/plasmocyte, neutrophil, histiocyte, intracellular adhesion molecule-1 (ICAM-1), and platelet endothelial cell adhesion molecule-1 (PECAM-1) were assessed and hydroxyproline levels were measured in all three groups and compared using Kruskal-Wallis and ANOVA tests when appropriate. Macroscopically, both ω-3 FAs and 4 % icodextrin reduced adhesion formation but the difference was not statistically significant (P = 0.253). Histopathological examination revealed that there was no statistical significance in terms of giant cell, lymphocyte/plasmocyte, neutrophil, ICAM-1, and PECAM-1 scores; however, both ω-3 FAs and 4 % icodextrin were found to be prone to reduce fibrosis (P = 0.047), whereas in the ω-3 FA group, histiocytic reaction was significantly increased (P = 0.001), and hydroxyproline levels were significantly lower than other groups (P = 0.044). In this study, ω-3 FAs were found to be superior to 4 % icodextrin with the lower hydroxyproline level and greater histiocytic reaction. Considering these results, ω-3 FAs can be a promising agent in the prevention of adhesion formation.

The effect of raloxifene, a SERM, on extracellular matrix protein expression of pelvic fibroblasts

INTRODUCTION AND HYPOTHESIS

We hypothesize that the abnormal extracellular matrix (ECM) turnover in pelvic tissues of women with prolapse may be attenuated by raloxifene. We examine the effect of raloxifene on ECM protein expression in pelvic fibroblasts.

METHODS

Pelvic fibroblasts were isolated from cases (N = 6) and controls (N = 3). Cells were treated with raloxifene. Dose-response analyses were performed by ANOVA. mRNA and protein expression of collagen I, III, MMPs, and TIMPs were determined by RT-PCR and Western blot. MMP activity was analyzed by zymography.

RESULTS

The mRNA expression of TIMP-3 and protein expression of TIMP-1 and TIMP-3 were significantly increased by raloxifene in fibroblasts from both cases and controls (P < 0.05). Collagen I, III, and MMP mRNA and protein expressions were not affected.

CONCLUSIONS

Raloxifene selectively attenuates abnormal matrix degradation by increasing inhibitors of proteases, TIMPs, in pelvic fibroblasts. This opens the possibility for SERMs to be used as preventive therapy for pelvic floor disorders.

Omega-3 fatty acids in cancer, the protectors of good and the killers of evil?

Omega-3 fatty acids have been implicated in cancer prevention and treatment. Conventional chemotherapeutics are considered "double-edged swords", as they kill the cancer cells but also strike the healthy cells causing severe morbidity and sometimes also mortality. Could omega-3 fatty acids in this setting work as a "sword and shield" instead, by being cytotoxic to cancer cells, but at the same time protect healthy cells from these deleterious effects? In addition, may our current diet with decreased omega-3/omega-6 ratio contribute to the increased cancer incidence, and could an omega-3 enriched diet be used as a preventive measure against cancer? Here, we seek answers to these questions by reviewing the effects of omega-3 fatty acids, particularly DHA, on various cancers with emphasis on a cancer of neural origin, neuroblastoma. Results from preventive and therapeutic animal as well as human studies together with mechanisms behind the observed toxicity are summarized.

Review: cellular metabolism: contribution to postoperative adhesion development

Postoperative adhesions are a significant source of morbidity, including contributions to pelvic pain, bowel obstruction, and infertility. While the mechanisms of postoperative adhesion development are complex and incompletely understood, hypoxia appears to trigger a cascade of intracellular responses involving hypoxia-inducible factors, lactate, reactive oxygen species, reactive nitrogen species, and insulin-like growth factors that results in manifestation of the adhesion phenotype. Thus, substantial evidence exists to implicate the direct role of cellular metabolism in wound repair and adhesion development.

Cytokine orchestration in post-operative peritoneal adhesion formation

Peritoneal adhesions are a near inevitable occurrence after laparotomy and a major cause of both patient and physician misery. To date, clinical attempts at their amelioration have concentrated on manipulating the physical factors that affect their development despite a wealth of experimental data elucidating the molecular mechanisms that underlie their initiation, development and maturation. However, the advent of targeted, specific anti-cytokine agents as directed therapy for inflammatory and neoplastic conditions raises the prospect of a new era for anti-adhesion strategies. To harness this potential will require considerable cross-disciplinary collaboration and that surgeon-scientists propel themselves to the forefront of this emerging field.