Hypoxia-generated superoxide induces the development of the adhesion phenotype

Advanced postoperative tissue antiadhesive membranes enabled with electrospun nanofibers

Tissue adhesion is one of the most common postoperative complications, which is frequently accompanied by inflammation, pain, and even dyskinesia, significantly reducing the quality of life of patients. Thus, to prevent the formation of tissue adhesions, various strategies have been explored. Among these methods, placing anti-adhesion membranes over the injured site to separate the wound from surrounding tissues is a simple and prominently favored method. Recently, electrospun nanofibers have been the most frequently investigated antiadhesive membranes due to their tunable porous structure and high porosities. They not only can act as an essential barrier and functional carrier system but also allow for high permeability and nutrient transport, showing great potential for preventing tissue adhesion. Herein, we provide a short review of the most recent applications of electrospun nanofibrous antiadhesive membranes in tendons, the abdominal cavity, dural sac, pericardium, and meninges. Firstly, each section highlights the most representative examples and they are sorted based on the latest progress of related research. Moreover, the design principles, preparation strategies, overall performances, and existing problems are highlighted and evaluated. Finally, the current challenges and several future ways to develop electrospun nanofibrous antiadhesive membranes are proposed. The systematic discussion and proposed directions can shed light on ideas and guide the reasonable design of electrospun nanofibrous membranes, contributing to the development of exceptional tissue anti-adhesive materials in the foreseeable future.

Prevention strategies of postoperative adhesion in soft tissues by applying biomaterials: Based on the mechanisms of occurrence and development of adhesions

Postoperative adhesion (POA) widely occurs in soft tissues and usually leads to chronic pain, dysfunction of adjacent organs and some acute complications, seriously reducing patients' quality of life and even being life-threatening. Except for adhesiolysis, there are few effective methods to release existing adhesion. However, it requires a second operation and inpatient care and usually triggers recurrent adhesion in a great incidence. Hence, preventing POA formation has been regarded as the most effective clinical strategy. Biomaterials have attracted great attention in preventing POA because they can act as both barriers and drug carriers. Nevertheless, even though much reported research has been demonstrated their efficacy on POA inhibition to a certain extent, thoroughly preventing POA formation is still challenging. Meanwhile, most biomaterials for POA prevention were designed based on limited experiences, not a solid theoretical basis, showing blindness. Hence, we aimed to provide guidance for designing anti-adhesion materials applied in different soft tissues based on the mechanisms of POA occurrence and development. We first classified the postoperative adhesions into four categories according to the different components of diverse adhesion tissues, and named them as "membranous adhesion", "vascular adhesion", "adhesive adhesion" and "scarred adhesion", respectively. Then, the process of the occurrence and development of POA were analyzed, and the main influencing factors in different stages were clarified. Further, we proposed seven strategies for POA prevention by using biomaterials according to these influencing factors. Meanwhile, the relevant practices were summarized according to the corresponding strategies and the future perspectives were analyzed.

Targeting Lysyl Oxidase as a Potential Therapeutic Approach to Reducing Fibrotic Scars Post-operatively: Its Biological Role in Post-Surgical Scar Development

Abdominal and pelvic surgery, or any surgical injury of the peritoneum, often leads to chronic abdominal adhesions that may lead to bowel obstruction, infertility, and pain. Current therapeutic strategies are usually ineffective, and the pathological mechanisms of the disease are unclear. Excess collagen cross-linking is a key mediator for extra-cellular matrix deposition and fibrogenesis. Lysyl oxidase is a key enzyme that catalyzes the formation of stabilizing cross-links in collagen. Dysregulation of Lysyl oxidase (Lox) expressing upregulates collagen cross-linking, leading ECM deposition. Tissue hypoxia during surgery induces molecular mechanisms and active transcription factors to promote the expression of several genes related to inflammation, oxidative stress, and fibrosis, such as transforming growth factor beta, and Lox. Studies have shown that targeting Lox improves clinical outcomes and fibrotic parameters in liver, lung, and myocardial fibrosis, therefore, Lox may be a potential drug target in the prevention of postsurgical adhesion.

The link between intrauterine adhesions and impaired reproductive performance: a systematic review of the literature

Background

Intrauterine adhesions (IUAs) are one of the main reproductive system diseases in women worldwide. Fusion between the injured opposing walls leads to partial-to-complete obliteration of the cavity and/or cervical canal. The main clinical manifestations in case of IUAs are menstrual disturbances, cyclic pain and reproductive disorders. The reproductive outcomes of women with IUAs remain limited and inefficient compared to women without IUAs, even after adhesiolysis. An exact understanding of the underlying mechanisms and processes to explain the compromised reproductive performance and outcomes in case of IUAs are lacking.

Methods

A systematic literature review of MEDLINE-PubMed (1966 to January 2022) and EMBASE (1974 to January 2022) was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were included if they reported underlying causes, related mechanisms and processes to explain the association between IUAs and impaired reproductive performance, pregnancy and obstetric complications.

Results

After an extensive review of the literature, 58 articles were identified reporting underlying mechanisms to explain the association between IUAs and impaired fertility. Intrauterine scarring influences the process of fertilization, reproductive performance and ultimately reproductive outcome. IUAs can disturb the cervico-utero-tubal sperm transport and result in an avascular and unresponsive endometrium with decreased receptivity and thickness. Abnormal decidualization and abnormal trophoblastic infiltration leads to placental attachment disorders. Moreover, the risk for premature delivery, intrauterine fetal growth restriction and fetal anomalies is increased in case of IUAs.

Conclusion

The impact of IUAs on reproductive performance, even after adhesiolysis, is becoming more apparent. The postulated mechanisms to explain the association are related to sperm transport, embryo implantation and placentation. Prevention, by preserving the basal layer of the endometrium is essential. Effective and evidence-based strategies for the prevention of endometrial injury and formation of IUAs, are urgently needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-05164-2.

Intestinal Anastomotic Healing: What do We Know About Processes Behind Anastomotic Complications

Colorectal surgery has developed rapidly in the recent decades. Nevertheless, colorectal anastomotic leakage continues to appear postoperatively in unpleasant rates and leads to life-threatening conditions. The development of valid complication-preventing methods is inefficient in many aspects as we are still lacking knowledge about the basics of the process of anastomotic wound healing in the gastrointestinal tract. Without the proper understanding of the crucial mechanisms, research for prevention of anastomotic leakage is predestined to be unsuccessful. This review article discusses known pathophysiological mechanisms together with the most lately found processes to be further studied. The aim of the article is to facilitate the orientation in the topic, support the better understanding of known mechanisms and suggest promising possibilities and directions for further research.

Elucidating the Novel Mechanism of Ligustrazine in Preventing Postoperative Peritoneal Adhesion Formation

Postoperative peritoneal adhesion (PPA) is a major clinical complication after open surgery or laparoscopic procedure. Ligustrazine is the active ingredient extracted from the natural herb Ligusticum chuanxiong Hort, which has promising antiadhesion properties. This study is aimed at revealing the underlying mechanisms of ligustrazine in preventing PPA at molecular and cellular levels. Both rat primary peritoneal mesothelial cells (PMCs) and human PMCs were used for analysis in vitro. Several molecular biological techniques were applied to uncover the potential mechanisms of ligustrazine in preventing PPA. And molecular docking and site-directed mutagenesis assay were used to predict the binding sites of ligustrazine with PPARγ. The bioinformatics analysis was further applied to identify the key pathway in the pathogenesis of PPA. Besides, PPA rodent models were prepared and developed to evaluate the novel ligustrazine nanoparticles in vivo. Ligustrazine could significantly suppress hypoxia-induced PMC functions, such as restricting the production of profibrotic cytokines, inhibiting the expression of migration and adhesion-associated molecules, repressing the expression of cytoskeleton proteins, restricting hypoxia-induced PMCs to obtain myofibroblast-like phenotypes, and reversing ECM remodeling and EMT phenotype transitions by activating PPARγ. The antagonist GW9662 of PPARγ could restore the inhibitory effects of ligustrazine on hypoxia-induced PMC functions. The inhibitor KC7F2 of HIF-1α could repress hypoxia-induced PMC functions, and ligustrazine could downregulate the expression of HIF-1α, which could be reversed by GW9662. And the expression of HIF-1α inhibited by ligustrazine was dramatically reversed after transfection with si-SMRT. The results showed that the benefit of ligustrazine on PMC functions is contributed to the activation of PPARγ on the transrepression of HIF-1α in an SMRT-dependent manner. Molecular docking and site-directed mutagenesis tests uncovered that ligustrazine bound directly to PPARγ, and Val 339/Ile 341 residue was critical for the binding of PPARγ to ligustrazine. Besides, we discovered a novel nanoparticle agent with sustained release behavior, drug delivery efficiency, and good tissue penetration in PPA rodent models. Our study unravels a novel mechanism of ligustrazine in preventing PPA. The findings indicated that ligustrazine is a potential strategy for PPA formation and ligustrazine nanoparticles are promising agents for preclinical application.

Intraperitoneal Triamcinolone Reduces Postoperative Adhesions, Possibly through Alteration of Mitochondrial Function

Adhesions frequently occur postoperatively, causing morbidity. In this noninterventional observational cohort study, we enrolled patients who presented for repeat abdominal surgery, after a history of previous abdominal myomectomy, from March 1998 to June 20210 at St. Vincent’s Catholic Medical Centers. The primary outcome of this pilot study was to compare adhesion rates, extent, and severity in patients who were treated with intraperitoneal triamcinolone acetonide during the initial abdominal myomectomy (n = 31) with those who did not receive any antiadhesion interventions (n = 21), as documented on retrospective chart review. Adhesions were blindly scored using a standard scoring system. About 32% of patients were found to have adhesions in the triamcinolone group compared to 71% in the untreated group (p < 0.01). Compared to controls, adhesions were significantly less in number (0.71 vs. 2.09, p < 0.005), severity (0.54 vs. 1.38, p < 0.004), and extent (0.45 vs. 1.28, p < 0.003). To understand the molecular mechanisms, human fibroblasts were incubated in hypoxic conditions and treated with triamcinolone or vehicle. In vitro studies showed that triamcinolone directly prevents the surge of reactive oxygen species triggered by 2% hypoxia and prevents the increase in TGF-β1 that leads to the irreversible conversion of fibroblasts to an adhesion phenotype. Triamcinolone prevents the increase in reactive oxygen species through alterations in mitochondrial function that are HIF-1α-independent. Controlling mitochondrial function may thus allow for adhesion-free surgery and reduced postoperative complications.

Genetic and Epidemiological Similarities, and Differences Between Postoperative Intraperitoneal Adhesion Development and Other Benign Fibro-proliferative Disorders

Intraperitoneal adhesions complicate over half of abdominal-pelvic surgeries with immediate, short, and long-term sequelae of major healthcare concern. The pathogenesis of adhesion development is similar to the pathogenesis of wound healing in all tissues, which if unchecked result in production of fibrotic conditions. Given the similarities, we explore the published literature to highlight the similarities in the pathogenesis of intra-abdominal adhesion development (IPAD) and other fibrotic diseases such as keloids, endometriosis, uterine fibroids, bronchopulmonary dysplasia, and pulmonary, intraperitoneal, and retroperitoneal fibrosis. Following a literature search using PubMed database for all relevant English language articles up to November 2020, we reviewed relevant articles addressing the genetic and epidemiological similarities and differences in the pathogenesis and pathobiology of fibrotic diseases. We found genetic and epidemiological similarities and differences between the pathobiology of postoperative IPAD and other diseases that involve altered fibroblast-derived cells. We also found several genes and single nucleotide polymorphisms that are up- or downregulated and whose products directly or indirectly increase the propensity for postoperative adhesion development and other fibrotic diseases. An understanding of the similarities in pathophysiology of adhesion development and other fibrotic diseases contributes to a greater understanding of IPAD and these disease processes. At a very fundamental level, blocking changes in the expression or function of genes necessary for the transformation of normal to altered fibroblasts may curtail adhesion formation and other fibrotic disease since this is a prerequisite for their development. Similarly, applying measures to induce apoptosis of altered fibroblast may do the same; however, apoptosis should be at a desired level to simultaneously ameliorate development of fibrotic diseases while allowing for normal healing. Scientists may use such information to develop pharmacologic interventions for those most at risk for developing these fibrotic conditions.

Platelet 3D Preservation Using a Novel Biomimetic Nanofiber Peptide for Reduced Apoptosis and Easy Storage

Human platelets (PLTs) are vulnerable to unfavorable conditions, and their adequate supply is limited by strict transportation conditions. We report here that PLTs preserved under three-dimensional (3D) conditions using novel biomimetic nanofiber peptides showed reduced apoptosis compared with classical PLTs stored at 22 °C and facilitated the storage and transportation of PLTs. The mechanism of PLT 3D preservation involves the formation of cross-links and a 3D nanofibrous network by a self-assembled peptide scaffold material at physiological conditions after initiation by triggers in plasma. PLTs adhere to the surface of the nanofibrous network to facilitate the 3D distribution of PLTs. The 3D microstructure, rheological properties, and effect on the inflammatory response and hemolysis were evaluated. Compared to traditional PLTs stored at 22 °C, PLTs subjected to 3D preservation showed similar morphology, number, aggregation activity, and reduced apoptosis. The detection of the reactive oxygen species (ROS) levels demonstrated that both reduced intracellular and mitochondrial ROS levels were correlated with reduced apoptosis. This study reveals a new 3D preservation method for PLTs based on the use of novel biomimetic nanofiber peptides that presents an attractive opportunity for various biomedical applications.

Evaluation of the Therapeutic Effects of the Hydroethanolic Extract of Portulaca oleracea on Surgical-Induced Peritoneal Adhesion

Objective

Peritoneal adhesion (PA) is an abnormal connective tissue that usually occurs between tissues adjacent to damaged organs during processes such as surgery. In this study, the anti-inflammatory and antioxidant effects of Portulaca oleracea (PO) were investigated against postoperative-induced peritoneal adhesion.

Methods

Thirty healthy male Wistar rats (220 ± 20 g, 6-8 weeks) were randomly divided into four groups: (1) normal, (2) control (induced peritoneal adhesion), and (3) and (4) PO extracts (induced peritoneal adhesion and received 100 or 300 mg/kg/day of PO extract for seven days). Finally, macroscopic and microscopic examinations were performed using different scoring systems and immunoassays in the peritoneal lavage fluid.

Results

We found that the levels of adhesion scores and interleukin- (IL-) 1β, IL-6, IL-10, tumour necrosis factor- (TNF-) α, transforming growth factor- (TGF-) β ₁, vascular endothelial growth factor (VEGF), and malondialdehyde (MDA) were increased in the control group. However, PO extract (100 and 300 mg/kg) notably reduced inflammatory (IL-1β, IL-6, and TNF-α), fibrosis (TGF-β ₁), angiogenesis (VEGF), and oxidative (MDA) factors, while increased anti-inflammatory cytokine IL-10, antioxidant factor glutathione (GSH), compared to the control group.

Conclusion

Oral administration of PO improved postoperational-induced PA by alleviating the oxidative factors, fibrosis, inflammatory cytokines, angiogenesis biomarkers, and stimulating antioxidative factors. Hence, PO can be considered a potential herbal medicine to manage postoperative PA. However, further clinical studies are required to approve the effectiveness of PO.

Post-Operative Adhesions: A Comprehensive Review of Mechanisms

Post-surgical adhesions are common in almost all surgical areas and are associated with significant rates of morbidity, mortality, and increased healthcare costs, especially when a patient requires repeat operative interventions. Many groups have studied the mechanisms driving post-surgical adhesion formation. Despite continued advancements, we are yet to identify a prevailing mechanism. It is highly likely that post-operative adhesions have a multifactorial etiology. This complex pathophysiology, coupled with our incomplete understanding of the underlying pathways, has resulted in therapeutic options that have failed to demonstrate safety and efficacy on a consistent basis. The translation of findings from basic and preclinical research into robust clinical trials has also remained elusive. Herein, we present and contextualize the latest findings surrounding mechanisms that have been implicated in post-surgical adhesion formation.

Intra-abdominal propylene suture fragment leading to complete small bowel obstruction: A case report

Introduction

Propylene sutures are non-absorbable sterile surgical sutures, which when present intra-abdominally act as a foreign body leading to adhesion formation. Post-operative adhesions are a common cause of bowel obstruction, with complete closed loop obstruction presenting as a surgical emergency.

Case details

A 66-year-old man who had undergone a laparotomy for bowel obstruction two years back, presented to our emergency department with features of complete bowel obstruction. Midline laparotomy revealed propylene suture and intra peritoneal adhesions acting as a constricting band around the jejunum to be the cause.

Discussion

Adhesions are common perturbing problem after surgeries. The presence of a foreign body further incites the process of adhesion formation by causing hindrance to the fibrinolysis process. In this case, the adhesive bands acted synergistically with the encircling prolene suture material from the previous surgery in causing a complete loop obstruction.

Conclusion

Propylene sutures used in routine surgical procedures can migrate intra-abdominally, and lead to adhesion formation. Adhesions along with the non-absorbable suture can cause complete bowel obstruction.

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Propylene suture migrating and getting embedded within the bowel loops

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Foreign bodies incite an inflammatory reaction leading to more prolific adhesive band formation.

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Complete loop obstruction has a greater propensity to render parts of the bowel non-viable.

Salvia miltiorrhiza hydroalcoholic extract inhibits postoperative peritoneal adhesions in rats

Background

One of the most prevalent postoperative complications is believed to be intra-abdominal peritoneal adhesions, which is followed by several complications. Several adhesion prevention products have been examined, yet none of them were found to be completely effective. The current research is conducted to evaluate the beneficial effects of Salvia miltiorrhiza hydroalcoholic extract in inhibiting postoperative peritoneal adhesions in rats.

Methods

Forty rats were randomly classified into five equal groups (n = 8): 1) the normal group did not undergo surgical operations, 2) the control group in which the adhesion was induced, and which did not receive any treatment, 3) distilled water group that received distilled water, and 4,5) treatment groups treated with 1 and 5% of Salvia miltiorrhiza hydroalcoholic extract. The rats were euthanized 14 days following the surgery and the macroscopic score, the microscopic score of granulomatous inflammation and granulation tissue formation, IHC markers (vimentin, CD31, IL-1β, COX-2, and iNOS), and oxidative stress biomarkers (MDA, GPx, CAT, and TAC) were assessed in the experimental groups of the study.

Results

The difference between the control group and other groups for the adhesions macroscopic score, microscopic score, IHC markers, and oxidative stress biomarkers was significant (p < 0.05). Distilled water had no protective effect on the formation of peritoneal adhesions. Salvia miltiorrhiza treatment in two different doses significantly reduced macroscopic and microscopic scores, MDA concentration, Vimentin, IL-1β, COX-2, and iNOS compared to the control group (p < 0.05). The levels of GPx, CAT, and TAC in the treatment groups increased significantly compared with the control group (p < 0.05). Our findings revealed that a higher dose of Salvia miltiorrhiza was more effective in reducing peritoneal adhesions, proinflammatory and mesenchymal cell markers, and oxidative stress.

Conclusions

Salvia miltiorrhiza extract, owing to its strong antioxidant and anti-inflammatory properties, could effectively reduce peritoneal adhesions. Therefore, Salvia miltiorrhiza is recommended to be used as an effective anti-peritoneal post-operative adhesive agent.

A review of physiological and cellular mechanisms underlying fibrotic postoperative adhesion

Postoperative adhesions (PA) are fibrotic tissues that are the most common driver of long-term morbidity after abdominal and pelvic surgery. The optimal drug or material to prevent adhesion formation has not yet been discovered. Comprehensive understanding of cellular and molecular mechanisms of adhesion process stimulates the design of future anti-adhesive strategies. Recently, disruption of peritoneal mesothelial cells were suggested as the 'motor' of PA formation, followed by a cascade of events (coagulation, inflammation, fibrinolysis) and influx of various immune cells, ultimately leading to a fibrous exudate. We showed that a variety of immune cells were recruited into adhesive peritoneal tissues in patients with small bowel obstruction caused by PA. The interactions among various types of immune cells contribute to PA development following peritoneal trauma. Our review focuses on the specific role of different immune cells in cellular and humoral mechanisms underpinning adhesion development.

Is There a Genetic Predisposition to Postoperative Adhesion Development?

Adhesions are permanent fibrovascular bands between peritoneal surfaces, which develop following virtually all body cavity surgeries. The susceptibility to develop, and the severity, of adhesions following intra-abdominal surgery varies within and between individuals, suggesting that heritable factors influence adhesion development. In this manuscript, we discuss the pathophysiology of adhesion development from the perspective of genetic susceptibility. We restrict our discussion to genes and single-nucleotide polymorphisms (SNPs) that are specifically involved in, or that cause modification of, the adhesion development process. We performed a literature search using the PubMed database for all relevant English language articles up to March 2020 (n = 186). We identified and carefully reviewed all relevant articles addressing genetic mutations or single-nucleotide polymorphisms (SNPs) that impact the risk for adhesion development. We also reviewed references from these articles for additional information. We found several reported SNPs, genetic mutations, and upregulation of messenger RNAs that directly or indirectly increase the propensity for postoperative adhesion development, namely in genes for transforming growth factor beta, vascular endothelial growth factor, interferon-gamma, matrix metalloproteinase, plasminogen activator inhibitor-1, and the interleukins. An understanding of genetic variants could provide insight into the pathophysiology of adhesion development. The information presented in this review contributes to a greater understanding of adhesion development at the genetic level and may allow modification of these genetic risks, which may subsequently guide management in preventing and treating this challenging complication of abdominal surgery. In particular, the information could help identify patients at greater risk for adhesion development, which would make them candidates for anti-adhesion prophylaxis. Currently, agents to reduce postoperative adhesion development exist, and in the future, development of agents, which specifically target individual genetic profile, would be more specific in preventing intraperitoneal adhesion development.

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.

Asherman's Syndrome: it may not be all our fault

Asherman's Syndrome (AS) is an acquired condition defined by the presence of intrauterine adhesions (IUA) that cause symptoms such as menstrual abnormalities, pelvic pain, infertility, recurrent miscarriage, abnormal placentation and attendant psychological distress. Classically, AS is considered an iatrogenic disease triggered by trauma to the pregnant uterus. Different factors can cause the destruction of the endometrium, thus affecting the endometrial stem cell niche and creating IUAs. Curettage of the pregnant uterus appears to be the most common source of this destruction. Nevertheless, some AS cases have been associated with congenital uterine abnormalities and infections, and there are some idiopathic cases without any prior surgical procedures, suggesting a putative constitutional predisposition to IUA. Factors reported to cause AS share an underlying inflammatory mechanism leading to defective endometrial healing and vascularization. Interestingly, distinct genetic profiles have been observed in the endometrium of AS patients. These data suggest that AS might not just be an iatrogenic complication, but also the result of a genetic predisposition. Elucidating the possible physiopathological processes that contribute to AS will help to identify patients at risk for this condition, providing an opportunity for prevention.

The contribution of oxidative stress to platelet senescence during storage

BACKGROUND

Platelets for transfusion become senescent and dysfunctional during storage, resulting in a markedly short shelf life (5 days). We hypothesized that oxidative stress might account for this decline.

STUDY DESIGN AND METHODS

Human platelets were treated with or without antioxidants before storage, and samples were collected and analyzed at different time points. Platelet senescence was determined by senescence-associated β-galactosidase assay, and senescence-related platelet qualities were also analyzed.

RESULTS

Sign of senescence became evident after Day 3 and continued to increase over time. We also found that chemical induction of platelet activation did not affect senescence level, whereas apoptosis inducers showed a stimulative effect on platelet senescence. Moreover, this effect was not prevented by a pan-caspase inhibitor. Meanwhile, cellular and mitochondrial reactive oxygen species were found elevated during storage, and treatments with antioxidants successfully prevented this increase and also mitigated senescence levels of stored platelets. Finally, resveratrol, a natural antioxidant, was utilized as a novel storage additive to safely extend platelet shelf time. We showed that the addition of resveratrol efficiently postponed platelet senescence and ameliorated platelet storage lesion.

CONCLUSIONS

Platelets during storage became senescent and dysfunctional over time, and we found that oxidative stress might account for this decline. The addition of antioxidants effectively postponed senescence and ameliorated platelet storage lesion, which might provide a valuable reference to future platelet storage methodologies.

Evitar (l-Alanyl-l-Glutamine) Regulates Key Signaling Molecules in the Pathogenesis of Postoperative Tissue Fibrosis

Aims:

Hypoxia and the resulting oxidative stress play a major role in postoperative tissue fibrosis. The objective of this study was to determine the effect of l-alanyl-l-glutamine (Ala-Gln) on key markers of postoperative tissue fibrosis: hypoxia-inducible factor (HIF) 1α and type I collagen.

Methods:

Primary cultures of human normal peritoneal fibroblasts (NPF) established from normal peritoneal tissue were treated with increasing doses of Ala-Gln (0, 1, 2, or 10 mM) with hypoxia ([2% O2] 0-48 hours; continuous hypoxia) or after hypoxia (0.5, 1, 2, 4 hours) and restoration of normoxia (episodic hypoxia) with immediate treatment with Ala-Gln. Hypoxia-inducible factor 1α and type 1 collagen levels were determined by enzyme-linked immunosorbent assay. Data were analyzed with 1-way analysis of variance followed by Tukey tests with Bonferroni correction.

Results:

Hypoxia-inducible factor 1α and type I collagen levels increased in untreated controls by 3- to 4-fold in response to continuous and episodic hypoxia in human NPF. Under continuous hypoxia, HIF-1α and type I collagen levels were suppressed by Ala-Gln in a dose-dependent manner. l-alanyl-l-glutamine treatment after episodic hypoxia also suppressed HIF-1α and type I collagen levels for up to 24 hours for all doses and up to 48 hours at the highest dose, regardless of exposure time to hypoxia.

Conclusions:

l-alanyl-l-glutamine significantly suppressed hypoxia-induced levels of key tissue fibrosis (adhesion) phenotype markers under conditions of continuous as well as episodic hypoxia in vitro. This effect of glutamine on molecular events involved in the cellular response to insult or injury suggests potential therapeutic value for glutamine in the prevention of postoperative tissue fibrosis.

Pharmacological HIF-inhibition attenuates postoperative adhesion formation

Peritoneal adhesions represent a common complication of abdominal surgery, and tissue hypoxia is a main determinant in adhesion formation. Reliable therapeutic options to reduce peritoneal adhesions are scarce. We investigated whether the formation of postsurgical adhesions can be affected by pharmacological interference with hypoxia-inducible factors (HIFs). Mice were treated with a small molecule HIF-inhibitor, YC-1 (3-[5′-Hydroxymethyl-2′-furyl]-1-benzyl-indazole), or vehicle three days before and seven days after induction of peritoneal adhesions or, alternatively, once during induction of peritoneal adhesions. Pretreatment or single intraperitoneal lavage with YC-1 significantly reduced postoperative adhesion formation without prompting systemic adverse effects. Expression analyses of cytokines in peritoneal tissue and fluid and in vitro assays applying macrophages and peritoneal fibroblasts indicated that this effect was cooperatively mediated by various putatively HIF-1α-dependent mechanisms, comprising attenuated pro-inflammatory activation of macrophages, impaired recruitment and activation of peritoneal fibroblasts, mitigated epithelial-mesenchymal-transition (EMT), as well as enhanced fibrinolysis and impaired angiogenesis. Thus, this study identifies prevention of postsurgical peritoneal adhesions as a novel and promising field for the application of HIF inhibitors in clinical practice.

Peripheral serotonin regulates postoperative intra-abdominal adhesion formation in mice

The aim of the present study is to investigate the role and potential mechanisms of peripheral serotonin in postoperative intra-abdominal adhesion formation in mice. The caecum-rubbing operations were conducted for intra-abdominal adhesion formation modelling in wild-type and Tph1−/− mice. The deficiency of serotonin significantly decreased the adhesion scores, weight loss, and adhesion thickness as well as levels of collagen fibres and hydroxyproline in the adhesive tissues. The Tph1−/− mice exhibited a milder inflammatory response and oxidative stress in the adhesive tissues than did the wild-type mice. Moreover, the deficiency of serotonin reduced the levels of PAI-1 and fibrinogen, and raised the t-PA and t-PA/PAI levels in the peritoneal fluids. Moreover, the expressions of CD34, VEGF, TGF-β and 5-HT_2B receptor in the adhesive tissues were significantly decreased in the Tph1−/− group mice. Furthermore, the Tph1−/− +5-HTP group showed more severe adhesions than did the Tph1−/− group mice, and the p-chlorophenylalanine (PCPA) could markedly alleviated the adhesion formation in the WT mice. In conclusion, the present study showed that peripheral serotonin regulated postoperative intra-abdominal adhesion formation by facilitating inflammation, oxidative stress, disorder of the fibrinolytic system, angiopoiesis and TGF-β1 expression via the 5-HT_2B receptor in the adhesive tissues.

Adhesion phenotype manifests an altered metabolic profile favoring glycolysis

OBJECTIVE

To determine whether metabolic markers are differentially expressed in normal and adhesion fibroblasts with and without hypoxia exposure.

DESIGN

Prospective experimental study.

SETTING

University research laboratory.

PATIENT(S)

Fibroblasts established from normal peritoneum and adhesion tissues from the same patients.

INTERVENTION(S)

In vitro experiments on normal peritoneal and adhesion fibroblasts under normal and hypoxic (2% O2) conditions.

MAIN OUTCOME MEASURE(S)

Expression of metabolic markers, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), glucose transporter 1 (GLUT1), hypoxia inducible factor (HIF)-1α, hexokinase 2 (HK2), lactose dehydrogenase A (LDHA), and pyruvate dehydrogenase alpha 1 (PDHA1) were measured using real-time reverse transcription polymerase chain reaction; adenosine triphosphate (ATP), HIF-1α, and lactate levels were assessed with ELISAs.

RESULT(S)

Baseline mRNA levels of GAPDH and HIF-1α were increased, while GLUT1 and PDHA1 were decreased in adhesion as compared with in normal peritoneal fibroblasts. There was no change in baseline levels of HK2 or LDHA between the cell lines. Hypoxia increased protein levels of HIF-1α and mRNA levels of GAPDH, GLUT1, and HK2 and decreased levels of PDHA1 in both cell lines. Hypoxia increased LDHA mRNA levels in normal peritoneal fibroblasts. Baseline levels of lactate and ATP were lower in adhesion as compared with in normal peritoneal fibroblasts. In response to hypoxia, there was an increase in lactate in both cell lines and a decrease in ATP in normal fibroblasts.

CONCLUSION(S)

Adhesion fibroblasts manifested an altered metabolic profile, which favors the glycolytic pathway, and is further altered by hypoxia. Targeting these specific metabolic markers during surgery can be an important therapeutic intervention minimizing the development of postoperative adhesions.

Pycnogenol prevents peritoneal adhesions

PURPOSE

This study tested the ability of pycnogenol, an extract from the bark of the French maritime pine (Pinus pinaster), to prevent intra-abdominal adhesions.

METHODS

Thirty female Wistar albino rats were separated randomly into three equal groups: Group (1) the control group, which underwent surgery, but was given no drug; Group (2) given 10 mg/kg of pycnogenol dissolved in normal saline intraperitoneally for 10 days after surgery; and Group (3) given 0.1 mL of normal saline for 10 days intraperitoneally after surgery. On post-operative day 10, all of the animals were killed and any adhesions were evaluated macroscopically and histopathologically.

RESULTS

The macroscopic adhesion scores (mean ± SD) for Groups 1, 2, and 3 were 2.5 ± 0.53, 0.60 ± 0.70, and 2.0 ± 0.82, respectively. The macroscopic adhesion score was significantly lower in Group 2 than in Groups 1 and 3 (p < 0.001). All three components of the histopathological evaluation (inflammation, fibrosis, and neovascularization) were significantly lower in Group 2 than in Groups 1 or 3 (p < 0.001, p < 0.001, and p = 0.004, respectively).

CONCLUSIONS

Pycnogenol was found to be effective at preventing surgery-related adhesions in an animal model.

Predisposing factors to post-operative adhesion development

BACKGROUND

Adhesion development is the most common sequelae of intra-abdominal and pelvic surgery and represents a significant, yet poorly understood, cause of morbidity among post-operative patients. It remains unclear, for example, exactly why adhesions form more frequently in certain tissues and/or patients, or at specific locations within them, as opposed to others. This review contributes to the growing knowledge pool by elucidating factors that potentially predispose to the development of adhesions. Given the strong correlation between a hypofibrinolytic state and adhesion formation, this review article will examine not only those factors that have been shown to directly predispose to adhesion development, but also those that are likely do so indirectly by means of altering the coagulation/fibrinolytic profile.

METHODS

A literature search was performed using the PubMed database for all relevant English language articles up to February 2014. All of the identified articles were reviewed with particular attention to predisposing factors to post-operative adhesion development. In addition, the reference lists of each article were reviewed to identify additional relevant articles.

RESULTS

Various factors have been shown to directly increase the risk of post-operative adhesion development; namely, certain genetic polymorphisms in the interleukin-1 receptor antagonist, increased estrogen exposure, and endometriosis. In addition, numerous factors are known to increase the risk of fibrosis, therefore likely increasing the risk of adhesion development indirectly. These factors include genetic polymorphisms in plasminogen activator inhibitor-1 and thrombin-activatable fibrinolysis inhibitor, diabetes mellitus, metabolic syndrome, hyperglycemia, obesity, depression, binge alcohol consumption, anti-Parkinsonian medications, oral hormone therapy, pregnancy, and cancer.

CONCLUSIONS

The literature reviewed in this paper will help to direct future research aimed at understanding the mechanisms that underlie the association of certain factors with adhesion development. This information will be crucial in the creation of adequate preventative and treatment strategies.

Inhibition of cyclooxygenase-2 prevents intra-abdominal adhesions by decreasing activity of peritoneal fibroblasts

BACKGROUND

Postoperative intra-abdominal adhesions are common complications after abdominal surgery. The exact molecular mechanisms that are responsible for these complications remain unclear, and there are no effective methods for preventing adhesion formation or reformation. The aim of the study reported here was to investigate the preventive effects and underlying potential molecular mechanisms of selective cyclooxygenase-2 (COX-2) inhibitors in a rodent model of postoperative intra-abdominal adhesions.

MATERIALS AND METHODS

The expression of COX-2 in postoperative intra-abdominal adhesions and normal peritoneal tissue was examined by immunohistochemistry and Western blot analysis. Assays were performed to elucidate the effect of COX-2 inhibition on hypoxia-induced fibroblast activity in vitro and on intra-abdominal adhesion formation in vivo.

RESULTS

Hypoxia-induced COX-2 expression in peritoneal fibroblasts was increased in postoperative intra-abdominal adhesions. Inhibition of COX-2 attenuated the activating effect of hypoxia on normal peritoneal fibroblasts in vitro. Data indicate that selective COX-2 inhibitor prevents in vivo intra-abdominal adhesion by inhibition of basic fibroblast growth factor and transforming growth factor-beta expression, but not through an antiangiogenic mechanism. Furthermore, using selective COX-2 inhibitors to prevent intra-abdominal adhesions did not adversely affect the weight, bowel motility, or healing of intestinal anastomoses in a rat model.

CONCLUSION

These results show that hypoxia-induced COX-2 expression in peritoneal fibroblasts is involved in the formation of intra-abdominal adhesions. Inhibition of COX-2 prevents postoperative intra-abdominal adhesions through suppression of inflammatory cytokines.

The biology of adhesion formation in the peritoneal cavity

Intraperitoneal adhesions are frequently encountered and present significant challenges to the practicing surgeon, including increased operating time, bowel obstruction, pelvic pain, and infertility. Until recently, however, our knowledge of the biology of adhesion formation within the peritoneal cavity has been limited, which in turn limits prevention and treatment strategies for surgical patients. Extensive research has now led to an increased understanding of adhesion formation, with hypoxia playing a central role. Hypoxia stimulates a cascade that leads to oxidative stress, anaerobic metabolism, formation of free radicals, and ultimately the adhesion phenotype. By understanding the precipitants to adhesion development, we may begin to develop prevention and treatment therapies that will provide clinically significant improvement over the currently available approaches to limit postoperative adhesions.

Nicotinamide adenine dinucleotide phosphate oxidase is differentially regulated in normal myometrium versus leiomyoma

Uterine fibroids are the most common benign tumor in women. The goal of this study was to investigate whether nicotinamide adenine dinucleotide phosphate oxidase (NOX), a major source of superoxide and subsequent oxidative stress, was differentially regulated in myometrium versus leiomyoma. Expression levels of NOXs1-5, dual oxidase (DUOX), DUOX2, NOX organizer (NOXO) 1, NOX activator 1, p47(phox), p67(phox), and p22(phox) were determined in cells treated with hypoxia by real-time reverse transcription-polymerase chain reaction, Western blot, and immunohistochemistry in tissues. Expression of NOX4 increased in fibroid compared to myometrial tissues and cells. The NOX2, DUOX1, and p67(phox) were higher while p22(phox) was lower in fibroid than that in myometrial cells. Hypoxia increased NOX4, DUOX1, and NOXO1 and decreased p22(phox) in myometrial and reduced DUOX1 in fibroid cells. The NOX1, NOX3, NOX5, and DUOX2 were undetectable. Fibroid cells are characterized by a unique NOX profile, which promotes a severe prooxidant state that may be responsible for their development. Targeting these subunits may be beneficial for future therapeutic interventions.

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.

Nicotinamide Adenine Dinucleotide Phosphate Oxidase Expression Is Differentially Regulated to Favor a Pro-oxidant State That Contributes to Postoperative Adhesion Development

We have previously reported that superoxide (O₂^•-) contributes to the development of postoperative adhesions. In this study, we determined whether O₂^•- generating nicotinamide adenine dinucleotide phosphate oxidase (NOX) is differentially expressed in normal peritoneal and adhesion fibroblasts and tissues. The NOX isoforms were measured utilizing Western blot, immunohistochemistry, high-performance liquid chromatography, and real-time reverse transcription polymerase chain reaction. Expression and activity of NOX were found to be significantly higher in adhesion tissues and cells than that in normal peritoneal tissues and cells (P < .05). Levels of NOX2, NOX4, NOX activating protein 1, DUOX1, p47^phox, and p22^phox messenger RNA increased in adhesion fibroblasts when compared to normal peritoneal and increased in response to hypoxia in normal peritoneal fibroblasts. Thus, adhesion fibroblasts are characterized by a unique NOX expression profile, which maintains a pro-oxidant state that may be responsible for the persistence of the adhesion phenotype. Decreasing the activity of NOX by targeting these isoforms may be beneficial for future therapeutic interventions of postoperative adhesions.

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.

Integrin-linked kinase mediates the hydrogen peroxide-dependent transforming growth factor-β1 up-regulation

Transforming growth factor type-β1 (TGF-β1) has been recognized as a central mediator in many pathological events related to extracellular matrix (ECM) proteins accumulation, where their locally increased expression has been implicated in the fibrosis process of numerous organs, including glomerular fibrosis in the kidney. We and others have reported the TGF-β1 synthesis regulation by reactive oxygen species (ROS), and moreover we also described the implication of integrin-linked kinase (ILK) in the AP-1-dependent TGF-β1 up-regulation. Thus, we propose here that hydrogen peroxide (H2O2)-dependent TGF-β1 regulation may be mediated by ILK activation. First we confirmed the increase in TGF-β1 expression in human mesangial cells (HMC) after treatment with H2O2 or with an alternative H2O2-generating system such as the glucose-oxidase enzyme (GOX). By using immunoblotting, immunofluorescence, and ELISA techniques, we demonstrate that extracellular H2O2 up-regulates TGF-β1 transcription, as well as increases TGF-β1 promoter activity. Furthermore, catalase-decreased intracellular H2O2 abolished TGF-β1 up-regulation. The use of pharmacological inhibitors as well as knockdown of ILK with small interfering RNA (siRNA) demonstrated the implication of a PI3K/ILK/AKT/ERK MAPK signaling pathway axis in the H2O2-induced TGF-β1 overexpression. Finally, we explored the physiological relevance of these findings by treating HMC with angiotensin II, a known stimuli of H2O2 synthesis. Our results confirm the relevance of previous findings after a more physiological stimulus. In summary, our results provide evidence that ILK activity changes may act as a mechanism in response to different stimuli such as H2O2 in the induced TGF-β1 up-regulation in pathological or even physiological conditions.

Increased platelet storage time is associated with mitochondrial dysfunction and impaired platelet function

BACKGROUND

Hemorrhagic shock is a leading cause of death following severe trauma, and platelet transfusions are frequently necessary to achieve hemostasis. Platelets, however, require special storage conditions, and storage time has been associated with loss of platelet quality. We hypothesized that standard storage conditions have a deleterious effect on platelet mitochondrial function and platelet activation.

MATERIALS AND METHODS

Platelet donations were collected from healthy donors (n = 5) and stored in gas-permeable collection bags according to American Association of Blood Bank recommendations. Platelet units were sampled from day of collection (day 0) until day 7. High-resolution respirometry was used to assess baseline mitochondrial respiration, maximal oxygen utilization, and individual mitochondrial complex-dependent respiration. Fluorescence-activated cell sorting was performed to analyze mitochondrial content, mitochondrial reactive oxygen species, the expression of P-selectin (both before and after challenge with thrombin receptor-activating peptide), and apoptosis. Data were analyzed using analysis of variance and Pearson correlation (P < 0.05 significant).

RESULTS

Mitochondrial respiration decreased significantly in platelets stored longer than 2 d (P < 0.05). Platelets also demonstrated a persistent decrease in response to stimulation with thrombin receptor-activating peptide by the third day of storage (P < 0.05) as well as an increase in mitochondrial reactive oxygen species and apoptosis (P < 0.05). Mitochondrial respiration significantly correlated with platelet capacity to activate (r = 0.8, P < 0.05).

CONCLUSIONS

Platelet mitochondrial respiratory function and activation response decrease significantly in platelets stored for 3 d or more. Because platelet transfusions almost universally occur between the third and fifth day of storage, our findings may have significant clinical importance and warrant further in vivo analysis.

[Effects of peroxynitrite derived from nitric oxide on cultured bovine ocular explants]

INTRODUCTION

Several studies have reported a significant production of nitric oxide (NO) with peroxynitrite formation in the setting of intraocular inflammation. In a previous study, we showed the cytotoxic effect of nitrites and nitrates, stable metabolites of NO, on the various tissues forming the layers of the eye, with variable degrees of tissue sensitivity. This study aims to investigate the effect of peroxynitrite on whole ocular bovine explants in culture.

METHODS

Healthy ocular bovine eyes, obtained immediately upon enucleation, were dissected and samples were taken from the anterior and posterior segments, and then cultured in DMEM supplemented with 10% fetal bovine serum, 2mM L-glutamine and antibiotics. Cultures were treated with 3-morpholino-sydonimin N-ethyl-carbamide (SIN-1) (molecule which produces NO and superoxide anion O(2)(.-)) at varying concentrations (100 to 500 μM) over 24 hours. After incubation, the explants were fixed in 10% buffered formalin, and histological study was performed.

RESULTS

Most of the structures showed changes on tissue and cellular levels after incubation with the peroxynitrite donor and various responses depending on the concentration used. These observations reflect variable concentration-dependent tissue sensitivity. The epithelia (cornea, iris and ciliary process) showed high sensitivity in comparison with sclera, which developed greater resistance.

CONCLUSION

In all, our results indicate a deleterious effect of peroxynitrite on bovine ocular structures in vitro. This effect is proportional to the concentration used. These results corroborate those reported by other teams and suggest the role of peroxynitrite derived from NO in the ocular lesions observed in the setting of uveitis.

Effects of hypoxia on the expression of inflammatory markers IL-6 and TNF-a in human normal peritoneal and adhesion fibroblasts

Inflammation is known to be involved in the postoperative adhesion development. Interleukin (IL)-6 and tumor necrosis factor (TNF)-α are cytokines that stimulate the acute-phase reaction, which leads to a systemic reaction including inflammation, fever, and activation of the complement and clotting cascades. The goal of this study was to examine the expression of these inflammatory markers, under normal and hypoxic conditions, in normal and adhesion fibroblasts. Primary cultures of fibroblasts were established from normal peritoneum and adhesion tissues from the same patient(s) and cultured under 20% O(2) or hypoxic 2% O(2) conditions for 24 hours. Cells were harvested and total RNA was isolated. Complimentary DNA was generated by reverse transcription and subjected to real-time RT-PCR using specific primers for IL-6 and TNF-α. Both normal peritoneal and adhesion fibroblasts expressed IL-6 and TNF-α. Adhesion fibroblasts exhibited significantly higher levels of IL-6 and TNF-α mRNA as compared to normal peritoneal fibroblasts (p < 0.05). Both IL-6 and TNF-α mRNA levels were upregulated in response to hypoxia in both normal peritoneal and adhesion fibroblasts. The increase in IL-6 and TNF-α mRNA levels of normal fibroblasts reached the levels observed in adhesion fibroblasts. Our results suggest that hypoxia promotes the development of the adhesion phenotype by the induction of inflammatory markers, which may contribute to the development of postoperative adhesions. The inhibition of inflammation may be a potential therapeutic approach in the prevention and/or reduction of postoperative adhesion development.

Prevention of peritoneal adhesions: a promising role for gene therapy

Adhesions are the most frequent complication of abdominopelvic surgery, yet the extent of the problem, and its serious consequences, has not been adequately recognized. Adhesions evolved as a life-saving mechanism to limit the spread of intraperitoneal inflammatory conditions. Three different pathophysiological mechanisms can independently trigger adhesion formation. Mesothelial cell injury and loss during operations, tissue hypoxia and inflammation each promotes adhesion formation separately, and potentiate the effect of each other. Studies have repeatedly demonstrated that interruption of a single pathway does not completely prevent adhesion formation. This review summarizes the pathogenesis of adhesion formation and the results of single gene therapy interventions. It explores the promising role of combinatorial gene therapy and vector modifications for the prevention of adhesion formation in order to stimulate new ideas and encourage rapid advancements in this field.

Postoperative adhesion development following cesarean and open intra-abdominal gynecological operations: a review

In this review, we discuss the pathophysiology of adhesion development, the impact of physiological changes associated with pregnancy on markers of adhesion development, and the clinical implications of adhesion development following cesarean delivery (CD). Although peritoneal adhesions develop after the overwhelming majority of intra-abdominal and pelvic surgery, there is evidence in the literature that suggests that patients having CD may develop adhesions less frequently. However, adhesions continue to be a concern after CD, and are likely significant, albeit on average less than after gynecological operations, but with potential to cause significant delay in the delivery of the baby with serious, lifelong consequences. Appreciation of the pathophysiology of adhesion development described herein should allow a more informed approach to the rapidly evolving field of intra-abdominal adhesions and should serve as a reference for an evidence-based approach to consideration for the prevention and treatment of adhesions.

Modulation of redox signaling promotes apoptosis in epithelial ovarian cancer cells

OBJECTIVE

Epithelial ovarian cancer (EOC) cells are known to be resistant to apoptosis through a mechanism that may involve alteration in their redox balance. NADPH oxidase is a major source of intracellular superoxide, which is converted to the less toxic product by superoxide dismutase (SOD). Superoxide contributes to hypoxia inducible factor (HIF)-1α stabilization. We sought to determine the effects of inhibiting the generation of intracellular reactive oxygen species (ROS) on apoptosis of EOC cells.

METHODS

Diphenyleneiodonium (DPI), an irreversible ROS inhibitor, was used to inhibit the generation of ROS in EOC cell lines, SKOV-3 and MDAH-2774, followed by assessment of apoptosis, NADPH oxidase, SOD3 and HIF-1α expression. A combination of immunohistochemistry, immunoprecipitation/western blot, and real-time RT-PCR were utilized to evaluate the expression of these enzymes in EOC cells as well as normal ovarian tissue and ovarian cancer tissue specimens.

RESULTS

DPI treatment significantly induced apoptosis in both EOC cell lines as evident by increased caspase-3 activity and TUNEL assay. Additionally, both EOC cell lines were found to express NADPH oxidase, HIF-1α, and SOD3, which were highly sensitive to DPI treatment. DPI treatment resulted in reduced NADPH oxidase, SOD3 and HIF-1α levels. Furthermore, ovarian cancer tissues were found to manifest higher NADPH oxidase levels as compared to normal ovarian tissues.

CONCLUSIONS

These data suggest that lowering oxidative stress, possibly through the inhibition of NADPH oxidase, induces apoptosis in ovarian cancer cells and may serve as a potential target for cancer therapy.

Peritoneal adhesions in human and veterinary medicine: from pathogenesis to therapy. A review

Any peritoneal inflammatory process consequent to infections or surgical injuries may induce abdominal adhesion formation. Peritoneal adhesions are connective laciniae that develop among abdomino-pelvic organs that limit physiologic visceral motion. Consequently, fertility may be impaired, and intestinal obstruction and pelvic pain may develop, mainly in subjects that had undergone gynaecological surgery. This review illustrates the pathogenic steps of adhesiogenesis and the therapeutic scenario that evolved over the years to tackle the threat of peritoneal adhesions, both in domestic animals and in women.

Intra-abdominal adhesions: definition, origin, significance in surgical practice, and treatment options

BACKGROUND

Intra-abdominal adhesions arise after more than 50% of all abdominal operations and are an important source of postoperative complications. They attach normally separated organs to each other and can cause major problems for the affected patients by giving rise to small bowel obstruction, chronic pelvic pain, dyspareunia, infertility, and higher complication rates in subsequent operations. They are also a frequent source of medicolegal conflict. Thus, every physician should be familiar with their mechanism of origin, their consequences, and the methods by which they can be prevented.

METHODS

A selective PubMed/Medline search from 1960 onward as well as articles to which these publications referred. The expert consensus position of the European Society for Gynaecological Surgery is also taken into consideration.

RESULTS

Adhesions arise through aberrant wound healing after peritoneal injury with further influence from a variety of other factors. Preventive measures include minimizing peritoneal injury intraoperatively through the meticulous observance of basic surgical principles, moistening the mesothelium to keep it from drying out, irrigating the peritoneal cavity to remove blood and clot, and keeping the use of intra-abdominal foreign material to a minimum.

CONCLUSION

Adhesions are an inevitable consequence of intra-abdominal surgery. They can be prevented to some extent with meticulous surgical technique and certain other measures. For operations carrying a high risk of postoperative adhesions, e.g., surgery on the adnexa or bowel, commercially available peritoneal instillates or barrier methods can be used to limit adhesion formation.

Exposure to polychlorinated biphenyls enhances lipid peroxidation in human normal peritoneal and adhesion fibroblasts: a potential role for myeloperoxidase

Nitric oxide, superoxide, and lipid peroxidation (LPO) produced under oxidative stress may contribute to the development of postoperative adhesions. The objective of this study was to determine the effects of polychlorinated biphenyls (PCBs) on LPO, superoxide dismutase, myeloperoxidase (MPO), and nitrite/nitrate in human normal peritoneal and adhesion fibroblasts. PCB treatment reduced inducible nitric oxide synthase (iNOS) expression as well as levels of nitrite/nitrate in both cell lines. Although there was no difference in iNOS expression between the two cell lines, adhesion fibroblasts manifested lower basal levels of MPO compared to normal peritoneal fibroblasts. There was a reduction in MPO expression and its activity in response to PCB treatment in normal peritoneal fibroblasts; however, this effect was minimal in adhesion fibroblasts. Moreover, adhesion fibroblasts manifested higher levels of LPO compared to normal peritoneal fibroblasts, whereas PCB treatment increased LPO levels in both cell types. We conclude that PCBs promote the development of the adhesion phenotype by generating an oxidative stress environment. This is evident by lower iNOS, MPO, and nitrite/nitrate and a simultaneous increase in LPO. Loss of MPO activity, possibly through a mechanism involving MPO heme depletion and free iron release, is yet another source of oxidative stress.

Periods without agitation diminish platelet mitochondrial function during storage

BACKGROUND

Prolonged periods without agitation produce platelet (PLT) storage lesions that result in reduced in vitro assay parameters and an increase of apoptotic markers during storage. The aim of this study was to evaluate the influence of periods without agitation on PLT mitochondrial function, blood gases, and activation.

STUDY DESIGN AND METHODS

Apheresis PLT units (n = 12) were collected using a cell separator and each was equally divided among five storage bags (50 mL of PLT suspension in 300-mL nominal volume containers). Four bags were held without agitation for 24, 48, 72, and 96 hours in a standard shipping box at room temperature and the fifth bag was continuously agitated. PLTs were assayed for standard in vitro PLT assays as well as for mitochondrial membrane potential (MMP), accumulation of reactive oxygen species, Annexin V binding, mitochondrial mass, and activity of mitochondrial reduction power (MRP) immediately after removal of units from the shipping container on Days 1, 2, 3, 4, and 7.

RESULTS

Increasing periods without agitation resulted in increased superoxide anion generation and PLT activation as well as reduced PLT MMP and MRP. Increasing periods without agitation resulted in increasing Annexin V binding. PLTs that had undergone periods without agitation showed increased oxygen and carbon dioxide levels immediately after storage without agitation. The superoxide anion generation was highly correlated with the loss of MMP, increasing Annexin V binding, and pH decline.

CONCLUSIONS

PLTs, if stored without agitation, produce a lesion that leads PLTs to apoptosis. The severity of the lesion depends on the length of the period without agitation. Prolonged periods without agitation induce formation of superoxides and depolarization of MMP along with a presentation of apoptotic markers.

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.