Regulation of expression of tissue plasminogen activator and plasminogen activator inhibitor-1 by dichloroacetic acid in human fibroblasts from normal peritoneum and adhesions

İntrabdominal Adezyon Oluşum Mekanizmalarına ve Tedavi Stratejilerine Histopatolojik Bakış

Hayat standartlarını olumsuz etkileyen abdominal adezyonlar, postoperatif dönemde görülen önemli bir sağlık sorunudur. Peritoneal kavite ve serozal yüzeylerde oluşan, abdominal travmalara sebep olan kimyasal ve termal faktörler ya da enfeksiyon ve yabancı cisim reaksiyonları adezyon oluşumuna sebep olabilir. Abdominal adezyonların sınıflandırması genellikle adezyon yoğunluğuna ve prognoz ciddiyetine göre yapılsa da henüz dünya çapında kabul görmüş standart bir sınıflandırma sistemi mevcut değildir. Abdominal adezyonlar ağrı, infertilite, cerrahi sonrası hastanede yatış süresinin uzaması ve ekonomik yük gibi olumsuz sonuçlarla klinik yansımalar gösterir. Sonuç olarak, postoperatif süreçte karşılaşılan adezyonlar ciddi bir sorundur ve adezyon oluşumunu engellemek için ileri çalışmaların laboratuvar ortamından klinik araştırma modellerine uyarlanması gerekmektedir. Bu derleme çalışması intraabdominal adezyon oluşumu, histopatolojisi, derecelendirilmesi, önlenmesi ve klinik önemi ile ilgili literatürü gözden geçirmek için hazırlanmıştır.

Chemical Scalpel: An Experimental Collagenase-Based Treatment for Peritoneal Adhesions

(1) Background: Abdominal adhesions are a common disease appearing after any type of abdominal surgery and may prolong surgical time and cause intestinal obstruction, infertility, or chronic pain. We propose the use of intraperitoneal collagenase to perform chemical adhesiolysis based on the pathophysiology and histology of adhesions. (2) Methods: We generated an adhesion model with intraperitoneal polypropylene meshes. Four months later, we evaluated the efficacy of the treatment in blinded form, i.e., 0.05% collagenase vs. placebo at 37 °C for 20 min. Protocol 1: Ten rats with ten mesh fragments, in which an attempt was made to remove the maximum number of meshes in a 5-min period. Protocol 2: Six rats with four mesh fragments in the sides of the abdominal cavity in which adhesiolysis was performed using a device that measures burst pressure. (3) Results: Protocol 1: 42% efficacy in the collagenase group versus 8% in the control group (p < 0.013). Protocol 2: 188.25 mmHg (SD 69.65) in the collagenase group vs. 325.76 mmHg (SD 50.25) in the control group (p < 0.001). (4) Conclusions: Collagenase allows for the safe and effective chemical adhesiolysis in this experimental model of adhesions.

Prevention of intestinal adhesion and regeneration of abdominal wall tissue with meshes containing an electrostatically spun acellular dermal matrix (ADM)/silk fibroin (SF) fiber composite polypropylene mesh

The repair of abdominal wall defects often requires the use of polypropylene (PP) as the main material. After a PP mesh is implanted in the body, contact with the intestine can cause adhesions between the intestine and the mesh, leading to serious complications such as intestinal fistula. In this study, we used electrostatic spinning technology to coat one side of PP meshes with an electrostatically spun isolating layer of acellular dermal matrix (ADM)/silk fibroin (SF) hybrid material. These meshes were used to repair abdominal wall defects in model rats and were compared with polycaprolactone (PCL) composite polypropylene meshes and PP meshes. The results showed that the adhesion score and area of ADM/SF-PP meshes were smaller than those of PCL-PP and PP meshes. Immunohistochemical assessment revealed that the ADM/SF meshes could effectively reduce the inflammatory response at the contact surface between the meshes and abdominal organs. The tissues regenerated on the abdominal side were rich in new blood vessels. Furthermore, the ADM/SF meshes could effectively reduce the expression levels of the inflammation-related factors IL-6 and TNF-α. The expression levels of tissue regeneration-related factors, such as VEGF and PAX-7, were also higher after ADM/SF-PP mesh-mediated repair than after PCL-PP mesh and PP mesh repair. Thus, ADM/SF-PP meshes can effectively reduce the inflammatory response at the contact surface between the meshes and abdominal organs and quickly promote regeneration of abdominal surface tissue to prevent and reduce abdominal adhesion and support restoration of the abdominal wall.

Extensive Adhesions in Living Donor Liver Transplantation: A Retrospective Analysis

BACKGROUND

Adhesions are abnormal fibrous bands of scar tissue between internal organs and tissues. With respect to recipient hepatectomy in living donor liver transplantation (LDLT), we defined extensive adhesions as adhesions in at least two separate locations that required more than 5 % of the total surgical time to lyse. We aimed to identify the etiology and consequences of this preventable burden.

METHODS

A simple retrospective case-control study of all cases with extensive adhesions from August 2011 to September 2014 matched by age, sex, and diagnosis at surgery.

RESULTS

A total of 380 cases were studied. Thirty-eight and five patients had extensive adhesions from surgical and non-surgical causes, respectively. The incidence and complications in pediatric patients were far less than in adults. In the adult group, the mean operative time was increased by 75 min (12.3 %) and blood loss by 2.5 L.The incidence of bowel perforation and biliary infections were increased in adults, while there was no significant difference in the rate of ascitic or wound infections. The 1-year survival was slightly less (92 %) than the control group (100 %).

CONCLUSIONS

The most common cause of extensive adhesions at LDLT was prior liver resection. Extensive adhesions caused increased morbidity by increased blood loss, transfusion requirements, and increased cold ischemia time. There is also a higher risk of bowel perforation during enterolysis. The use of commercially available barrier techniques is advisable in adults at high risk of developing adhesions with a possibility of liver transplantation, such as liver resection for HCC.

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.

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.

Involvement of NADPH oxidase in oxidized LDL-induced upregulation of heat shock factor-1 and plasminogen activator inhibitor-1 in vascular endothelial cells

Plasminogen activator inhibitor-1 (PAI-1) is implicated in thrombogenesis, inflammation, and extracellular matrix remodeling. Previous studies indicated that oxidized low-density lipoprotein (LDL) stimulated the generation of PAI-1 in vascular endothelial cells (EC). The present study demonstrated that LDL oxidized by copper, iron, or 3-morpholinosydnonimine increased the expression of NADPH oxidase (NOX) 2, PAI-1, and heat shock factor-1 (HSF1) in human umbilical vein EC or coronary artery EC compared with LDL or vehicle. Diphenyleneiodonium, a NOX inhibitor, prevented the increases of the expression of HSF1 and PAI-1 in EC induced by oxidized LDLs. Small-interference RNA (siRNA) for p22(phox), an essential subunit of NOX, prevented oxidized LDL-induced expression of NOX2, HSF1, and PAI-1 in EC. HSF1 siRNA inhibited oxidized LDL-induced expression of PAI-1 and HSF1, but not NOX2, in EC. The binding of HSF1 to PAI-1 promoter and the activity of PAI-1 promoter in EC were enhanced by oxidized LDL. Butylated hydroxytulene, a potent antioxidant, inhibited oxidized LDL-induced release of hydrogen peroxide (H(2)O(2)) and the expression of NOX2, HSF1, and PAI-1 in EC. Treatment with H(2)O(2) increased the abundance of NOX2, HSF1, and PAI-1 in EC. The results of the present study indicate that oxidized LDL-induced expression of NOX may lead to the elevated release of reactive oxygen species, the activation of HSF1, and the enhancement of the transcription of PAI-1 gene in cultured vascular EC.

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.

Hypoxia-generated superoxide induces the development of the adhesion phenotype

Adhesion fibroblasts exhibit higher TGF-beta1 and type I collagen expression as compared to normal peritoneal fibroblasts. Furthermore, exposure of normal peritoneal fibroblasts to hypoxia results in an irreversible increase in TGF-beta1 and type I collagen. We postulated that the mechanism by which hypoxia induced the adhesion phenotype is through the production of superoxide either directly or through the formation of peroxynitrite. To test this hypothesis, normal peritoneal and adhesion fibroblasts were treated with superoxide dismutase (SOD), a superoxide scavenger, and xanthine/xanthine oxidase, a superoxide-generating system, under normoxic and hypoxic conditions. Also, cells were treated with peroxynitrite. TGF-beta1 and type I collagen expression was determined before and after all treatments using real-time RT/PCR. Hypoxia treatment resulted in a time-dependent increase in TGF-beta1 and type I collagen mRNA levels in both normal peritoneal and adhesion fibroblasts. Similarly, treatment with xanthine oxidase, to endogenously generate superoxide, resulted in higher mRNA levels of TGF-beta1 and type I collagen in both normal peritoneal and adhesion fibroblasts. In contrast, treatment with SOD, to scavenge endogenous superoxide, resulted in a decrease in TGF-beta1 and type I collagen expression in adhesion fibroblasts to levels seen in normal peritoneal fibroblasts; no effect on the expression of these molecules was seen in normal peritoneal fibroblasts. Exposure to hypoxia in the presence of SOD had no effect on mRNA levels of TGF-beta1 and type I collagen in either normal peritoneal or adhesion fibroblasts. Peroxynitrite treatment alone significantly induced both adhesion phenotype markers. In conclusion, hypoxia, through the production of superoxide, causes normal peritoneal fibroblasts to acquire the adhesion phenotype. Scavenging superoxide, even in the presence of hypoxia, prevented the development of the adhesion phenotype. These findings further support the central role of free radicals in the development of adhesions.

Peritoneal adhesions and intestinal obstructions in patients with familial Mediterranean fever--are they more frequent?

OBJECTIVE

Familial Mediterranean fever (FMF) is characterized by recurrent episodes of peritonitis. A controversy exists as to whether intestinal obstruction due to peritoneal adhesions is more common among FMF patients compared with healthy controls. The aim of the study was to estimate the rate of spontaneous or postsurgical small-bowel obstruction (SBO) in FMF patients.

METHODS

We reviewed the charts of 560 FMF patients followed in our clinic for the occurrence of spontaneous SBO. We also assessed the occurrence of postappendectomy intestinal obstruction among 89 FMF patients compared with 417 individuals without FMF who underwent an appendectomy without other abdominal surgery in the same medical center.

RESULTS

Ten of 471 FMF patients (2.1%) developed spontaneous SBO, 8 of whom required laparotomy and adhesiolysis. Six of 89 FMF patients (6.7%) who underwent appendectomy developed SBO. None of the non-FMF patients developed SBO.

CONCLUSIONS

Our retrospective study showed that FMF patients are at a higher risk than healthy individuals for developing SBO either spontaneously or as a postsurgical complication. Physicians should be alert to this possible complication when FMF patients arrive at the emergency room.

Modulation of the expression of peroxisome proliferators-activated receptors in human fibroblasts

To determine the levels of peroxisome proliferators-activated receptors (PPARs) in normal and adhesion fibroblasts, we utilized real-time reverse transcription-polymerase chain reaction to measure messenger RNA (mRNA) levels in fibroblasts from normal peritoneum and adhesions from five patients in both the presence or absence of dichloroacetic acid (DCA) and a cyclooxygenase-2 (COX-2) inhibitor, NS-398. Peroxisome proliferators-activated receptor alpha, PPARbeta, PPARgamma1, and PPARgamma2 mRNA are all present in normal peritoneal and adhesion fibroblasts, and selectively rose in response to hypoxia and either DCA or NS-398.

Dichloroacetate Reduces Tissue Necrosis in a Rat Transverse Rectus Abdominis Musculocutaneous Flap Model

OBJECTIVE

Ischemia-related complications may occur during postmastectomy transverse rectus abdominis musculocutaneous (TRAM) flap reconstruction. The aim of our study was to investigate whether necrosis of susceptible flap regions could be reduced by dichloroacetate (DCA)-induced stimulation of oxidative metabolism in hypoxic tissue.

METHODS

The study was a randomized control trial using male Sprague-Dawley rats. A pedicled TRAM flap based upon the right inferior epigastric artery was elevated and reapproximated. Animals were randomly assigned to 1 of 5 treatment groups (n = 6). Group I received no DCA; groups II through V were administered 75 mg/kg DCA orally 24 hours preoperative; in addition, groups II through IV received 75 mg/kg/d DCA orally postoperative for 4 days; group III also received 75 mg/kg DCA (IP) intraoperatively; groups IV and V were given 15 mg/kg/d DCA orally for 6 days before the 24-hour preoperative treatment. Four days postsurgery, skin paddles were photographed and assessed for viability. Underlying TRAM muscle was biopsied for histologic analysis. Blood lactate levels were measured at pre- and postoperative time points. The mean percentages of viable skin paddle were as follows: 32.0%+/- 4.0% (group I), 68.1% +/- 6.2% (group II), 84.3% +/- 5.9% (group III), 92.8% +/- 2.0% (group IV), 82.6% +/- 5.8% (group V).

RESULTS

Statistically significant differences were found in all experimental (DCA) groups relative to the controls (P < 0.01). Group IV (6-day DCA preconditioning, plus 24-hour preoperative and 4-day postoperative treatment) displayed the greatest improvement in flap viability, significantly better than other DCA groups (P < 0.01). Group IV also had significantly lower serum lactate levels than controls (P < 0.05). Histologic examination of muscle biopsies revealed reductions in inflammation and necrosis correlating with DCA treatment and skin paddle survival.

CONCLUSIONS

This study indicates that DCA may provide a useful pharmacologic tool for reducing ischemia-related necrosis in TRAM flaps.

Modulation of the expression of vascular endothelial growth factor in human fibroblasts

OBJECTIVE

To examine the up-regulation of vascular endothelial growth factor (VEGF) expression by hypoxia, a crucial event leading to neovascularization, as the reduction in VEGF expression may facilitate minimization of adhesion development.

DESIGN

Prospective experimental study.

SETTING

University medical center.

PATIENT(S)

Five patients with adhesions undergoing laparotomy with excision of adhesions and normal peritoneum.

INTERVENTION(S)

Adhesion and normal peritoneal fibroblasts were treated with dichloroacetic acid (DCA) or NS-398 (a cyclooxygenase-2 [COX-2] inhibitor) for 24 to 48 hours.

MAIN OUTCOME MEASURE(S)

A real-time reverse transcriptase polymerase chain reaction (RT-PCR) to quantify relative changes in mRNA levels of VEGF from each treatment.

RESULT(S)

In both normal peritoneal and adhesion fibroblasts, VEGF mRNA was present with statistically significantly higher levels in adhesion fibroblasts (32%). The DCA treatment resulted in a statistically significant decrease in VEGF mRNA levels in adhesion (20%) and normal peritoneal (18%) fibroblasts. The NS-398 treatment resulted in a statistically significant decrease in VEGF mRNA levels in adhesion (25%) and normal peritoneal (16%) fibroblasts.

CONCLUSION(S)

Stimulation of aerobic metabolism by DCA or inhibition of COX-2 by NS-398 reduces VEGF expression. Angiogenesis, which is an integral component in the development of dense vascular adhesions, may be reduced by either COX-2 inhibitors or stimulation of aerobic metabolism by DCA.

New anatomic repair of midline abdominal wall incisions extending to suprapubic region

This article describes a new technique to close infraumbilical midline abdominal wall incisions extending to the suprapubic region. This repair is technically easy to perform, saves time, reduces the risk of bowel and bladder injury and takes into consideration the anatomical landmarks of the peritoneum, the rectus sheath and the arcuate line. Abdominal wall closure with this repair is especially useful in obese patients. Furthermore, with this repair the pelvic cavity is lined with smooth peritoneum, which may reduce postoperative adhesions in the pelvis. Technically easy to perform and saves time Very useful technique for obese patients Reduced risk of bowel and bladder injury Anatomical in nature Potentially minimizes postoperative adhesions.