Randomized experimental study of two novel techniques for transanal repair of dehiscent low rectal anastomosis

BACKGROUND

Anastomotic leak after low anterior rectal resection is a dreadful complication. Early diagnosis, prompt management of sepsis followed by closure of anastomotic defect may increase chances of anastomotic salvage. In this randomized experimental study, we evaluated two different methods of trans-anal anastomotic repair.

METHODS

A model of anastomotic leak was created in 42 male pigs. Laparoscopic low anterior resection was performed with anastomosis created using a circular stapler with half of the staples removed. Two days later, animals were randomized into a TAMIS (trans-anal minimally invasive surgery) repair, endoscopic suture (ENDO) or control group with no treatment (CONTROL). Signs of intraabdominal infection (IAI), macroscopic anastomotic healing and burst tests were evaluated to assess closure quality after animals were sacrificed on the ninth postoperative day.

RESULTS

Closure was technically feasible in all 28 animals. Two animals had to be euthanized due to progressive sepsis at four and five days after endoscopic closure. Healed anastomosis with no visible defect was observed in 10/14 and 11/14 animals in TAMIS and ENDO groups, respectively, versus 2/14 in CONTROL (p < 0.05). Overall IAI rate was significantly lower in TAMIS (4/14; p = 0.006) and ENDO (5/14; p = 0.018) compared to CONTROL (12/14). Burst tests confirmed sealed closure in healed anastomosis with a median failure pressure of 190 (110-300) mmHg in TAMIS and 200 (100-300) mmHg in ENDO group (p = 0.644).

CONCLUSION

In this randomized experimental study, we found that both evaluated techniques are effective in early repair of dehiscent colorectal anastomosis with a high healing rate.

Retrospective study assessing efficacy and safety of left atrial appendage occlusion

OBJECTIVE

To describe the initial experience with Amplatzer Amulet in left atrial appendage occlusion in Slovakia. To evaluate procedural efficacy and safety.

BACKGROUND

Atrial fibrillation increases the risk of stroke. While anticoagulation therapy can reduce the risk of stroke, it is associated with bleeding risk and often unsatisfactory prescribed. Most thrombi form in the left atrium appendage, hence left atrium appendage occlusion may be a suitable therapeutic alternative for these patients.

METHODS

This is an observational, retrospective, single-centre, case-series study including 30 patients with atrial fibrillation at a high risk of stroke, undergoing left atrial appendage occlusion from June 2015 to December 2018.

RESULTS

The left atrial appendage was successfully closed in 29 (96.7 %) patients. Three months after the procedure, 4 patients had small leaks (< 2 mm). No complications were reported so far. Prior to the procedure, patients mostly received low molecular weight heparin (53.3 %). Three months after the procedure, patients mostly received acetylsalicylic acid (60.7 %) and clopidogrel (32.1 %).

CONCLUSION

Left atrial appendage occlusion was shown to be an effective and safe alternative to anticoagulation therapy in patients with atrial fibrillation, at a high risk of stroke and bleeding. The procedure is safe, when performed carefully even by less experienced cardiologists (Tab. 6, Fig. 4, Ref. 29). Text in PDF www.elis.sk Keywords: atrial fibrillation, stroke, haemorrhage, left atrial appendage occlusion, Amplatzer Amulet.

Two types of autologous cells in stricture development prevention after complete circular endoscopic dissection in minipig

INTRODUCTION

Complete circular endoscopic dissection (CED) is frequently accompanied with post-operative strictures formation in the esophagus. Various types of therapeutic approaches have recently been tested to prevent these strictures, e.g. cell therapy or stenting.

METHODS

Miniature pigs of Gottingen/Minnesota origin (n=10) were used in the study. First, we made the complete CED in the mid esophagus; next, the defect was left untreated or covered with mesenchymal stem cells (MSCs) or a mixture of MSCs and primary oral keratinocytes (pOKs) suspension without/with fully covered self-expandable metallic stent (SEMS). Consequently, we performed a control endoscopy with a stent removal, and necropsy was performed 17-36 days after cells application.

RESULTS

All CED procedures were completed successfully without serious complications. Although we were able to detect MSCs or pOKs in the post-CED defects up to the 36th day after transplantation, the combination of MSCs or MSCs/pOKs with or without SEMS application did not prevent post-CED strictures development. The mixture of MSCs and pOKs resulted in the formation of cellular aggregates, which were mainly observed in submucosa, and the post-CED defect was covered with collagen fibers containing a thin scarred epithelium, accompanied by various degrees of reconstruction and integrity.

CONCLUSION

Suspension application of autologous MSCs alone or in combination with pOKs with or without SEMS was ineffective in the prevention of strictures formation after complete CED. Nevertheless, the presence of MSCs or pOKs in the post-CED defect was confirmed even 5 weeks after transplantation.

Autologous transplantation of mesenchymal stem cells into the portal vein of the miniature pig; a preliminary experiment for NOTES approach

INTRODUCTION

There is evidence that mesenchymal stem cells (MSCs) could trans-differentiate into the liver cells in vitro and in vivo and thus may be used as an unfailing source for stem cell therapy of liver disease. Combination of MSCs (with or without their differentiation in vitro) and minimally invasive procedures as laparoscopy or Natural Orifice Transluminal Endoscopic Surgery (NOTES) represents a chance for many patients waiting for liver transplantation in vain.

METHODS

Over 30 millions of autologous MSCs at passage 3 were transplanted via the portal vein in an eight months old miniature pig. The deposition of transplanted cells in liver parenchyma was evaluated histologically and the trans-differential potential of CM-DiI labeled cells was assessed by expression of pig albumin using immunofluorescence.

RESULTS

Three weeks after transplantation we detected the labeled cells (solitary, small clusters) in all 10 samples (2 samples from each lobe) but no diffuse distribution in the samples. The localization of CM-DiI+ cells was predominantly observed around the portal triads. We also detected the localization of albumin signal in CM-DiI labeled cells.

CONCLUSION

The study results showed that the autologous MSCs (without additional hepatic differentiation in vitro) transplantation through the portal vein led to successful infiltration of intact miniature pig liver parenchyma with detectable in vivo trans-differentiation. NOTES as well as other newly developed surgical approaches in combination with cell therapy seem to be very promising for the treatment of hepatic diseases in near future.

Postoperative monitoring of colorectal anastomosis - experimental study

INTRODUCTION

Inadequate blood supply is one of the major risk factors for colorectal anastomotic leak. Early postoperative detection of local ischemic changes can predict complicated healing and lead to better outcome. Microdialysis (MD) offers real-time evaluation of adequate bowel perfusion through monitoring of tissue metabolism. The aim of this study was to assess the feasibility of MD for early detection of ischemic changes in colorectal anastomosis.

METHOD

Five pigs with end-to-end colorectal anastomosis were included. MD catheter was placed intramurally 5mm from anastomotic edge. Occlusive ischemia was induced after 3 measurements and followed by another 3 hours of monitoring. Tissue levels of different metabolites were measured every 60 minutes before and after ischemia induction. Mann-Whitney test was used to compare pre and post ischemic changes.

RESULTS

The monitoring of colorectal anastomosis using MD was technically feasible and associated with no complications. Significant changes caused by local ischemia were observed in decreased levels of glucose or pyruvate and increased levels of lactate and glycerol. All metabolic changes were detectable already in first samples 60 minutes after ischemia induction.

CONCLUSION

Postoperative ischemic changes in colorectal anastomosis can be detected by means of microdialysis.Key words: colorectal anastomosis anastomotic leak microdialysis.

Fixation of biomaterial to metallic stent and fixation of stents after circular endoscopic dissection in the esophagus on an animal model

INTRODUCTION

Complete circular endoscopic (submucosal) resection (CER) performed using the endoscopic submucosal dissection (ESD) technique is burdened with a high incidence of post-operative strictures in the esophagus. The most effective method of preventing them is not known so far; one of the possible methods is to prevent these strictures directly at the site of their formation by covering the defect with a stent. The aim of the study was to find a way to fix a selected biomaterial to a stent, and subsequently, to fix the stent at the CER site to prevent esophageal strictures in an animal model.

METHOD

Miniature piglets from the Czech Academy of Sciences breeding unit in Libechov (N=10) were used. Endoscopy was performed using a single-channel endoscope. First, we made two circular mucosal cuts spaced 5 cm apart in the middle esophagus and we performed the CER between them using the endoscopic submucosal dissection technique. After that, we covered the defect with a stent coated with biomaterial (Xe-Derma®) while we tried to prevent stent migration into the stomach. For stent fixation, we tested endo-clips (N=3), the Apollo endoscopic system (N=1) and the suspension technique using two polyamide threads (N=6) anchored in the nasal septum. We performed a control endoscopy, stent removal and subsequent autopsy after 12 weeks.

RESULTS

All procedures were completed successfully without serious complications or deaths. Although stents covered with Xe-Derma® were applied to the entire resection area, one case of mediastinitis and one paraesophageal abscess were found during autopsy, most likely due to microperforations caused during the procedure. Histological analysis showed that after contact with the biomaterial, re-epithelisation took place within one week of application to the resection area. Stent migration occurred in each case when the stent was attached to the esophageal wall by endo-clips or with the endoscopic suture system (Apollo). There was no stent dislocation in the cases where the stent was suspended by two polyamide threads.

CONCLUSION

We developed a technique of fixing biomaterial to the surface of metallic stents which we used to prevent the formation of esophageal strictures after CER. Distal suspension fixation of the stent with a polyamide thread proved to be the most effective, while fixations by endo-clips or with the endoscopic suture system were ineffective.Key words: benign esophageal strictures circular endoscopic resection endoscopic submucosal dissection complication prevention.

Minipig model of Huntington's disease: ¹H magnetic resonance spectroscopy of the brain

Huntington's disease (HD) is an inherited autosomal neurodegenerative disorder affecting predominantly the brain, characterized by motor dysfunctions, behavioral and cognitive disturbances. The aim of this study was to determine changes in the brain of transgenic minipigs before HD onset using (1)H magnetic resonance (MR) spectroscopy. Measurements were performed on a 3 T MR scanner using a single voxel spectroscopy sequence for spectra acquisition in the white matter and chemical shift imaging sequence for measurement in the striatum, hippocampus and thalamus. A decrease of (phospho)creatine (tCr) concentration was found only in the thalamus (p=0.002) of transgenic minipigs, nevertheless we found significant changes in metabolite ratios. Increase of the ratio choline compounds (tCho)/tCr was found in all examined areas: striatum (p=0.010), thalamus (p=0.011) as well as hippocampus (p=0.027). The ratio N-acetylaspartate+N-acetylaspartylglutamate (tNAA)/tCr (p=0.043) and glutamate+glutamine (Glx)/tCr (p=0.039) was elevated in the thalamus, the ratio myo-inositol (Ins)/tCr (p=0.048) was significantly increased in the hippocampus. No significant differences were observed in the metabolite concentrations in the white matter, however we found significant increase of ratios tNAA/tCr (p=0.018) and tCho/tCr (p=0.003) ratios in transgenic boars. We suppose that the majority of the observed changes are predominantly related to changes in energy metabolism caused by decrease of tCr.

Survival and Differentiation of Human Embryonic Stem Cell-Derived Neural Precursors Grafted Spinally in Spinal Ischemia-Injured Rats or in Naive Immunosuppressed Minipigs: A Qualitative and Quantitative Study

In previous studies, we have demonstrated that spinal grafting of human or rat fetal spinal neural precursors leads to amelioration of spasticity and improvement in ambulatory function in rats with spinal ischemic injury. In the current study, we characterize the survival and maturation of three different human embryonic stem (ES) cell line-derived neural precursors (hNPCs) once grafted into ischemia-injured lumbar spinal cord in rats or in naive immunosuppressed minipigs. Proliferating HUES-2, HUES-7, or HUES-9 colonies were induced to form embryoid bodies. During the nestin-positive stage, the rosettes were removed and CD184+/CD271-/CD44-/CD24+ population of ES-hNPCs FAC-sorted and expanded. Male Sprague–Dawley rats with spinal ischemic injury or naive immunosuppressed Gottingen–Minnesota minipigs received 10 bilateral injections of ES-NPCs into the L2–L5 gray matter. After cell grafting, animals survived for 2 weeks to 4.5 months, and the presence of grafted cells was confirmed after staining spinal cord sections with a combination of human-specific (hNUMA, HO14, hNSE, hSYN) or nonspecific (DCX, MAP2, CHAT, GFAP, APC) antibodies. In the majority of grafted animals, hNUMA-positive grafted cells were identified. At 2–4 weeks after grafting, double-labeled hNUMA/ DCX-immunoreactive neurons were seen with extensive DCX+ processes. At survival intervals of 4–8 weeks, hNSE+ neurons and expression of hSYN was identified. Some hSYN-positive terminals formed putative synapses with the host neurons. Quantitative analysis of hNUMA+ cells at 2 months after grafting showed comparable cell survival for all three cell lines. In the presence of low-level immunosuppression, no grafted cell survival was seen at 4.5 months after grafting. Spinal grafting of proliferating pluripotent HUES-7 cells led to consistent teratoma formation at 2–6 weeks after cell transplantation. These data show that ES-derived, FAC-sorted NPCs can represent an effective source of human NPCs to be used in CNS cell replacement therapies.

Comparing over-the-scope clip versus endoloop and clips (KING closure) for access site closure: a randomized experimental study

BACKGROUND

A safe technique is essential for successful access site closure in Natural Orifice Translumenal Endoscopic Surgery (NOTES) and for closures of iatrogenic perforations.

AIM

To compare an over-the-scope clip (OTSC) versus an endoloop + endoclips closure technique (KING closure).

METHODS

40 minipigs underwent NOTES peritoneoscopy with liver biopsy. Gastrotomies and rectotomies were closed with OTSC (n = 20; 10× stomach, 10× rectum) or KING closure (n = 20; 10× stomach, 10× rectum). The animals were euthanized 28 days after the procedure. The main outcome variables were technical feasibility, effectiveness, and healing.

RESULTS

Stomach: All but one closure (KING) was successfully completed. The times of closure were similar between the techniques. At necropsy, all access sites were healed. In two animals (1× KING, 1× OTSC), an abscess, probably related to the closure technique, was found. Histologically, transmural healing with muscular bridging was observable in nine pigs for KING versus two pigs for OTSC closure (p = 0.003). Inflammation was present in three pigs for KING versus seven pigs for OTSC closure (p = 0.08). Rectum: All closures were successfully completed. The times of closure were similar between the techniques. At necropsy, all closure sites had healed. Transmural healing with muscular bridging was present in nine pigs for KING versus two pigs for OTSC closure (p = 0.003). Inflammation was present in two pigs for KING versus seven pigs for OTSC closure (p = 0.03). In one animal (OTSC), an enterocolic fistula developed in the proximity of the closure site.

CONCLUSIONS

OTSC and KING closure are comparable closure techniques in terms of technical feasibility and effectiveness. KING closure provides a superior histological outcome compared with OTSC closure.