Laparoscopic-type environment enhances mesothelial cell fibrinolytic activity in vitro via a down-regulation of plasminogen activator inhibitor-1 activity

Suspension culture promotes serosal mesothelial development in human intestinal organoids

Pluripotent-stem-cell-derived human intestinal organoids (HIOs) model some aspects of intestinal development and disease, but current culture methods do not fully recapitulate the diverse cell types and complex organization of the human intestine and are reliant on 3D extracellular matrix or hydrogel systems, which limit experimental control and translational potential for regenerative medicine. We describe suspension culture as a simple, low-maintenance method for culturing HIOs and for promoting in vitro differentiation of an organized serosal mesothelial layer that is similar to primary human intestinal serosal mesothelium based on single-cell RNA sequencing and histological analysis. Functionally, HIO serosal mesothelium has the capacity to differentiate into smooth-muscle-like cells and exhibits fibrinolytic activity. An inhibitor screen identifies Hedgehog and WNT signaling as regulators of human serosal mesothelial differentiation. Collectively, suspension HIOs represent a three-dimensional model to study the human serosal mesothelium.

Indications for the laparoscopic approach to acute small bowel obstruction: A retrospective review of 50 cases, a literature review, and a single hospital's preliminary experience

Small bowel obstruction (SBO) is mainly caused by postoperative adhesions, but a broad spectrum of diseases may cause this pathogenetic condition. Laparoscopic treatment represents an efficient approach to SBO. The aim of this paper was to review a single center's experience with a minimally invasive approach to multiple pathologic scenarios causing SBO. From January 2010 to December 2012, 50 consecutive patients underwent laparoscopic surgery for mechanical SBO. In 90% of patients, the surgical procedure was totally laparoscopic, while 10% required conversion to midline laparotomy. In-hospital morbidity was 15% among totally laparoscopic patients and 40% among those who underwent conversion to midline laparotomy. Thirty-day mortality was zero. One patient died 4 months postoperatively from neoplastic disease progression; the remaining patients were free from occlusive symptoms at follow-up. The minimally invasive technique applies to a broad spectrum of cases. A larger cohort of patients seems necessary to reproduce our results and confirm the effectiveness of a laparoscopic approach to SBO.

Preservation of peritoneal fibrinolysis owing to decreased transcription of plasminogen activator inhibitor-1 in peritoneal mesothelial cells suppresses postoperative adhesion formation in laparoscopic surgery

BACKGROUND

Postoperative adhesion formation is regulated by peritoneal fibrinolysis, which is determined by tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1). This study compared peritoneal fibrinolysis and adhesion formation after laparoscopic surgery (LAP) and open surgery (OP).

METHODS

We divided 154 male rats into 3 groups after cecal cauterization: Control, no treatment; LAP, CO2 pneumoperitoneum at 5 mmHg for 60 minutes; and OP, laparotomy for 60 minutes. Adhesions were quantified at day 7. The activity and mRNA level of tPA and PAI-1 were determined by enzyme-linked immunosorbent assay in plasma and peritoneal lavage and by real-time polymerase chain reaction in peritoneal mesothelial cells from omentum. We also examined peritoneal fibrinolysis in human gastric cancer patients treated with LAP (n = 14) or OP (n = 10).

RESULTS

In the animal study, adhesion scores, PAI-1 activity in peritoneal lavage fluid, and PAI-1 mRNA levels in peritoneal mesothelium were significantly greater in the OP group than the control and LAP groups. In the human study, postoperative PAI-1 mRNA levels were significantly greater in the OP group than the LAP group. Additionally, PAI-1 mRNA levels and subsequent adhesion formation were induced by prolonged operative time in the OP group, but not the LAP group.

CONCLUSION

Preservation of peritoneal fibrinolysis owing to decreased PAI-1 expression at the transcriptional level in peritoneal mesothelial cells is associated with suppression of postoperative adhesion formation in LAP. PAI-1 mRNA levels and subsequent adhesion formation were not induced by prolonged operative time in LAP. These results highlight the less invasiveness nature of LAP.

Severe inflammatory reaction induced by peritoneal trauma is the key driving mechanism of postoperative adhesion formation

BACKGROUND

Many factors have been put forward as a driving mechanism of surgery-triggered adhesion formation (AF). In this study, we underline the key role of specific surgical trauma related with open surgery (OS) and laparoscopic (LS) conditions in postoperative AF and we aimed to study peritoneal tissue inflammatory reaction (TIR), remodelling specific complications of open surgery (OS) versus LS and subsequently evaluating AF induced by these conditions.

METHODS

A prospective randomized study was done in 80 anaesthetised female Wistar rats divided equally into 2 groups. Specific traumatic OS conditions were induced by midline incision line (MIL) extension and tissue drying and specific LS conditions were remodelled by intraperitoneal CO2 insufflation at the 10 cm of water. TIR was evaluated at the 24th, 72nd, 120th and 168th hour by scoring scale. Statistical analysis was performed by the non-parametric t test and two-way ANOVA using Bonferroni post-tests.

RESULTS

More pronounced residual TIR was registered after OS than after LS. There were no significant TIR interactions though highly significant differences were observed between the OS and LS groups (p < 0.0001) with regard to surgical and time factors. The TIR change differences between the OS and LS groups were pronounced with postoperative time p < 0.05 at the 24th and 72nd; p < 0.01--120th and p < 0.001--168th hrs. Adhesion free wounds were observed in 20.0 and 31.0% of cases after creation of OS and LS conditions respectively; with no significant differences between these values (p > 0.05). However larger adhesion size (41.67 ± 33.63) was observed after OS in comparison with LS (20.31 ± 16.38). The upper-lower 95% confidential limits ranged from 60.29 to 23.04 and from 29.04 to 11.59 respectively after OS and LS groups with significant differences (p = 0.03). Analogous changes were observed in adhesion severity values. Subsequently, severe TIR parameters were followed by larger sizes of severe postoperative adhesions in the OS group than those observed in the LS group.

CONCLUSIONS

MIL extension and tissue drying seem to be the key factors in the pathogenesis of adhesion formation, triggering severe inflammatory reactions of the peritoneal tissue surrounding the MIL resulting in local and systemic consequences. CO2 insufflation however, led to moderate inflammation and less adhesion formation.

The role of laparoscopy in the management of acute small-bowel obstruction: a review of over 2,000 cases

BACKGROUND

Adhesive small-bowel obstruction (SBO) contributes significantly to emergency surgical workload. Laparotomy remains the standard approach. Despite published reports with high success rates and low morbidity, acute SBO is still considered by many a relative contraindication to laparoscopy. Our aim was to review the available literature and define important outcomes such as feasibility, safety, iatrogenic bowel injury, and benefits to patients with acute SBO who are approached laparoscopically.

METHODS

A systematic literature search was carried out using the Medline database and the search terms "laparoscopy" or "laparoscopic approach" and "bowel obstruction." Only adult studies published in English between 1990 and 2010 were included. Studies were excluded if data specific to outcomes for laparoscopic management of acute SBO could not be extracted.

RESULTS

Twenty-nine studies were identified. A laparoscopic approach was attempted in 2,005 patients with acute SBO. Adhesions were the most common etiology (84.9%). Laparoscopy was completed in 1,284 cases (64%), 6.7% were lap-assisted, and 0.3% were converted to hernia repair. The overall conversion rate to midline laparotomy was 29% (580/2,005). Dense adhesions, bowel resection, unidentified pathology, and iatrogenic injury accounted for the majority of conversions. When the etiology of SBO was a single-band adhesion, the success rate was 73.4%. Morbidity was 14.8% (283/1,906) and mortality was 1.5% (29/1,951). The enterotomy rate was 6.6% (110/1,673). The majority were recognized and converted to laparotomy. Laparoscopy was associated with reduced morbidity and length of stay.

CONCLUSION

Laparoscopy is a feasible and effective treatment for acute SBO with acceptable morbidity. Further studies are required to determine its impact on recurrent SBO.

Peritoneal changes due to laparoscopic surgery

Background

Laparoscopic surgery has been incorporated into common surgical practice. The peritoneum is an organ with various biologic functions that may be affected in different ways by laparoscopic and open techniques. Clinically, these alterations may be important in issues such as peritoneal metastasis and adhesion formation.

Methods

A literature search using the Pubmed and Cochrane databases identified articles focusing on the key issues of laparoscopy, peritoneum, inflammation, morphology, immunology, and fibrinolysis.

Results

Laparoscopic surgery induces alterations in the peritoneal integrity and causes local acidosis, probably due to peritoneal hypoxia. The local immune system and inflammation are modulated by a pneumoperitoneum. Additionally, the peritoneal plasmin system is inhibited, leading to peritoneal hypofibrinolysis.

Conclusion

Similar to open surgery, laparoscopic surgery affects both the integrity and biology of the peritoneum. These observations may have implications for various clinical conditions.

Fibrinolytic responses of human peritoneal fluid in laparoscopic cholecystectomy: a prospective clinical study

BACKGROUND

The reduction in peritoneal fibrinolysis is believed to be the pathogenetic mechanism of adhesion formation. The general conclusion based on previous clinical and experimental studies is that laparoscopic procedures produce less adhesion formation. The association between this beneficial effect of laparoscopic cholecystectomy and peritoneal fibrinolytic changes is not clear. Therefore, the authors aimed to compare the effects of open and laparoscopic cholecystectomy on peritoneal fibrinolysis. For this purpose, fibrinolytic parameters in peritoneal fluid were investigated 24 h after laparoscopic and open cholecystectomies.

METHODS

In a prospective clinical study, peritoneal fluid was sampled via a drain 24 h after laparoscopic (n = 10) and open (n = 9) cholecystectomies. Activities and concentrations of tissue plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1), and tPA/PAI-1 complex were determined by enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

In peritoneal fluids, tPA and tPA/PAI-1 complex concentrations were higher in the open cholecystectomy group (p = 0.009 and p < 0.001, respectively), but tPA activity and PAI-1 concentrations did not differ between the groups (p = 0.514 and p = 0.716, respectively).

CONCLUSIONS

Fibrinolytic changes in peritoneal fluid have several similarities in open and laparoscopic cholecystectomies with regard to tPA activity and PAI-1 levels. However, higher tPA levels after the open procedure probably are secondary to more intense tissue handling leading to mesothelial release of tPA.

Prevention of adhesions in gynaecological endoscopy

Adhesions resulting from gynaecological endoscopic procedures are a major clinical, social and economic concern, as they may result in pelvic pain, infertility, bowel obstruction and additional surgery to resolve such adhesion-related complications. Although the minimally invasive endoscopic approach has been shown to be less adhesiogenic than traditional surgery, at least with regard to selected procedures, it does not totally eliminate the problem. Consequently, many attempts have been made to further reduce adhesion formation and reformation following endoscopic procedures, and a wide variety of strategies, including surgical techniques, pharmacological agents and mechanical barriers have been advocated to address this issue. The present review clearly indicates that there is no single modality proven to be unequivocally effective in preventing post-operative adhesion formation either for laparoscopic or for hysteroscopic surgery. Furthermore, the available adhesion-reducing substances are rather expensive. Since excellent surgical technique alone seems insufficient, further research is needed on an adjunctive therapy for the prevention and/or reduction of adhesion formation following gynaecological endoscopic procedures.

Mesh Fixation Devices and Formation of Intraperitoneal Adhesions

PURPOSE

To investigate the effect of mesh fixation devices on the formation of intra-abdominal adhesions.

MATERIALS AND METHODS

Fourteen New Zealand rabbits were used. In seven animals, nickel-titanium (nitinol) anchors (group 1) and titanium tacks (group 2) were applied by laparoscopy on the right and left sides of the abdomen, respectively. In the remaining seven rabbits, the same devices were applied on prosthetic meshes (groups 3 and 4, respectively). On day 30, the rabbits were sacrificed and macroscopic adhesion scoring was performed. All the specimens were assessed by scanning electron microscopy (SEM).

RESULTS

All parameters of adhesion except extension were significantly higher in group 4 than group 3 (P < 0.05). Comparisons of group 1 vs. group 2 were not statistically significant (P > 0.05). All the comparisons between a nonmesh group and a mesh group resulted in significant differences. SEM results revealed that the mesothelial cell layer and connective tissue intensively covered the tacks in group 2 whereas no similar findings were observed in group 1. Comparable appearances were encountered in groups 3 and 4.

CONCLUSION

The nitinol anchor is associated with an acceptable level of adhesion formation and its intraperitoneal use can be considered safe in this regard.

Peritoneal nebulizer: a novel technique for delivering intraperitoneal therapeutics in laparoscopic surgery to prevent locoregional recurrence

BACKGROUND

Peritoneal involvement is a significant issue in the treatment of gastrointestinal malignancies. Current statistics indicate that after surgical intervention, up to 20% of patients will present with locoregional metastasis. The ability to inhibit initial tumor adhesion to the mesothelial lining of the peritoneum may be considered critical in the inhibition of tumor development. This article describes, the use of a novel nebulizer system capable of delivering high-concentration, low-dose therapeutics to the peritoneal cavity.

METHODS

For this study, 30 male WAG rats were inoculated with CC531 colorectal tumor cells. The rats were randomized into three groups: control group (n = 10), heparin-treated group (n = 10), and high-molecular-weight hyaluronan-treated group (n = 10). A peritoneal cancer index was used to determine tumor burden at 15 days. Analysis of variance (ANOVA) was used to compare multiple group means.

RESULTS

Nebulization therapy was performed without any complication in the cohort. Heparin inhibited macroscopic intraperitoneal tumor growth completely (p = 0.0001) without affecting tumor cell viability. The introduction of hyaluronan attenuated both tumor size and distribution, was compared with the control group (p = 0.002).

CONCLUSION

Nebulized heparin and hyaluronic acid using a novel nebulization technique attenuates peritoneal tumor growth after laparoscopic surgery. The technique itself is easy to use and safe.

Stress response to laparoscopic liver resection

The magnitude of the systemic response is proportional to the degree of surgical trauma. Much has been reported in the literature comparing metabolic and immune responses, analgesia use, or length of hospital stay between laparoscopic and open procedures. In particular, metabolic and immune responses are represented by measuring various chemical mediators as stress responses. Laparoscopic procedures are associated with reduced operative trauma compared with open procedures, resulting in lower systemic response. As a result, laparoscopic procedures are now well accepted for both benign and malignant processes. Laparoscopic liver resection, specifically, is employed for symptomatic and some malignant tumors, following improvements in diagnostic accuracy, laparoscopic devices, and techniques. However, laparoscopic liver resection is still controversial in malignant disease because of complex anatomy, the technical difficulty of the procedure, and questionable indications. There are few reports describing the stress responses associated with laparoscopic liver resection, even though many studies reviewing stress responses have been performed recently in both humans and animal models comparing laparoscopic to conventional open surgery. Although this review examines stress response after laparoscopic liver resection in both an animal and human clinical model, further controlled randomized studies with additional investigations of immunologic parameters are needed to demonstrate the consequences of either minimally invasive surgery or open procedures on perioperative or postoperative stress responses for laparoscopic liver resection.