Effects of amniotic membrane on the healing of primary colonic anastomoses in the cecal ligation and puncture model of secondary peritonitis in rats

Evaluation of colonic anastomosis healing using hybrid nanosheets containing molybdenum disulfide (MOS2) scaffold of human placental amniotic membrane and polycaprolactone (PCL) in rat animal model

Anastomosis is a standard technique following different conditions such as obstruction, tumor, and trauma. Obstruction, adhesion, or anastomosis leakage can be some of its complications. To improve healing and prevent postoperative complications, we design a hybrid scaffold containing acellular human amniotic membranes and polycaprolactone-molybdenum disulfide nanosheets for colon anastomosis. The animal model of colocolonic anastomosis was performed on two groups of rats: control and scaffold. The hybrid scaffold was warped around the anastomosis site in the scaffold group. Samples from the anastomosis site were resected on the third and seventh postoperative days for histopathological and molecular assessments. Histopathologic score and burst pressure had shown significant improvement in the scaffold group. No mortality and anastomosis leakage was reported in the scaffold group. In addition, inflammatory markers were significantly decreased, while anti-inflammatory cytokines were increased in the scaffold group. The result indicates that our hybrid scaffold is a proper choice for colorectal anastomosis repair by declining postoperative complications and accelerating healing.

Biological properties and surgical applications of the human amniotic membrane

The amniotic membrane (AM) is the inner part of the placenta. It has been used therapeutically for the last century. The biological proprieties of AM include immunomodulatory, anti-scarring, anti-microbial, pro or anti-angiogenic (surface dependent), and tissue growth promotion. Because of these, AM is a functional tissue for the treatment of different pathologies. The AM is today part of the treatment for various conditions such as wounds, ulcers, burns, adhesions, and skin injury, among others, with surgical resolution. This review focuses on the current surgical areas, including gynecology, plastic surgery, gastrointestinal, traumatology, neurosurgery, and ophthalmology, among others, that use AM as a therapeutic option to increase the success rate of surgical procedures. Currently there are articles describing the mechanisms of action of AM, some therapeutic implications and the use in surgeries of specific surgical areas, this prevents knowing the therapeutic response of AM when used in surgeries of different organs or tissues. Therefore, we described the use of AM in various surgical specialties along with the mechanisms of action, helping to improve the understanding of the therapeutic targets and achieving an adequate perspective of the surgical utility of AM with a particular emphasis on regenerative medicine.

Human Amniotic Membrane for the Treatment of Cryptoglandular Anal Fistulas

Background: Implantation of the amniotic membrane and their derivatives can have a beneficial effect on tissue repair and regeneration. We report for the first time the implant of an amniotic membrane in a patient affected by cryptoglandular anal fistula. Methods: A patch of human amniotic membrane was implanted in a female patient affected by an anterior transphincteric fistula. Following an accurate curettage of the anal fistula, the cryopreserved amniotic membrane was thawed and then washed in the operating room; one side of the membrane was transfixed with a resorbable suture thus creating an implantable fusiform patch. The membrane was subsequently implanted into the fistula tract from the external to the internal opening. The inner and outer parts of the membrane were then sutured to the internal and external fistula openings. Results: No intraoperative or postoperative complications occurred. The patient was discharged one day after the procedure after an uneventful hospitalization. At the 1-week, 1- and 3-month follow-up visits no pain (VAS 0) was referred by the patient and no inflammation was evident at the level of the previous external fistula opening. Conclusions: The implant of human amniotic membrane in a patient affected by cryptoglandular anal fistula was safely and easily performed. Moreover, future studies to assess the efficacy in the long-term follow-up are needed.

A randomized trial study on the effect of amniotic membrane graft on wound healing process after anal fistulotomy

Objective Human amniotic membrane (HAM) used as a wound coverage for more than a century. The aim of this study is to evaluate the efficacy of amniotic membrane on wound healing and reduce post-operative complication.

Study design Randomized clinical trial study.

Place and duration of study Surgery Department, Shahid Faghihi Hospital, Shiraz, in the period of between Sep. 2014 and Nov. 2015.

Methodology 73 patients with anal fistula were divided into two groups. The patients suffered from simple perianal fistula (low type) without any past medical history. Fistulotomy were performed for all of them and in interventional group HAM were applied as biologic dressing. Their wound healing improvement was evaluated post-operative in two groups.

Results From 73 patients participated in the study, 36 patients were in control group and 37 patients were in intervention group. According to the analysis of images taken from the wound, the rate of wound healing was 67.39% in intervention group and 54.51% in control group (p < 0.001). Discharge, pain, itching and stool incontinency was lower in intervention group. Analysis of pathology samples taken from the wound showed no differences between two groups.

Conclusion HAM application could lead to improvement of wound healing and reduced post-operative complications. In conclusion, HAM may act as a biologic dressing in the patients with anal fistula.

The Positive Effects of the Human Amniotic Membrane on the Healing of Staple Line After Sleeve Gastrectomy Applied Long-Evans Rat Model

BACKGROUND

The staple line leakage is a dangerous complication of sleeve gastrectomy. Various strategies have been tried to reduce the leakage risk. The amniotic membrane (AmM) is the inner layer of the placental membranes and has anti-inflammatory, anti-fibrosis, and anti-scarring effects, and it also has lower immune characteristics which are another essential characteristic of AmM concerning its utility for grafting. In this study, we aimed to investigate the impact of AmM on the staple line healing process of sleeve gastrectomy model in rats.

MATERIALS AND METHODS

We used twenty-eight Long-Evans rats in this study. Sleeve gastrectomy was performed with tristapler. Fourteen rats served as controls, AmM was applied staple line of the other fourteen. Fourteen animals were sacrificed (seven from the AmM applied group and the other seven from the control group) on the third postoperative day. And, the other fourteen animals were sacrificed (seven from the AmM applied group and seven from the control group) on the seventh postoperative day. The tissue around the staple line was evaluated microscopically and macroscopically, bursting pressures and hydroxyproline levels were also measured.

RESULTS

The bursting pressure and hydroxyproline measurements of the AmM applied group was significantly higher on the seventh postoperative day (p = 0.015, p = 0.012) Fibroblast activity and neoangiogenesis of the AmM applied group was also significantly higher on the seventh postoperative day (p = 0.004, p = 0.002).

CONCLUSION

This study showed that covering of staple line of sleeve gastrectomy model in rats significantly provided higher bursting pressures and increased hydroxyproline levels, fibroblast activity, and neoangiogenesis which may potentially lead a better staple line healing. We think further investigations are needed on this issue.

Human Amniotic Membrane Effect on Perianal Fistula Healing in Rabbits: An Experimental Study

BACKGROUND

Perianal fistula is a complicated disorder and most difficult to manage. New treatment methods would help surgeons to achieve a better outcome in patients with perianal fistula. Human amniotic membrane (HAM) has positive effects on wound healing in several conditions. The present study aimed to further determine the effect of HAM on wound healing of perianal fistula in rabbits.

METHODS

In a prospective experimental study, 14 male rabbits (aged 4-6 months and weighing 3-4 kg) were randomly divided into 2 groups. After 12 weeks, the high type perianal fistula was repaired with endorectal flap (ERF) and ERF plus HAM in the control and case groups, respectively. In all rabbits of the case group, a 1×1 cm width wrap of HAM was applied and fixed around the ERF site. Three weeks later, the repaired site of the perianal fistula was sent for pathologic wound healing scoring. The results were analyzed with the SPSS 21.0 software using Mann-Whitney test.

RESULTS

Six rabbits of each group survived the study period. There was a statistically significant difference in wound healing between the case and control groups (P<0.001). Wound healing process in the case group occurred better and faster than the control group.

CONCLUSION

HAM has an effective role in enhancing the ERF procedure and considered appropriate. A combination of HAM with other methods is recommended.

Human Amniotic Membrane Is Not Suitable for the Grafting of Colon Lesions and Prevention of Adhesions in a Xenograft Rat Model

INTRODUCTION

New biological materials are needed for specific applications in reconstructive bowel surgery and for the prevention of adhesion formation. Amniotic membranes (AMs) are assumed to have a number of unique characteristics that enhance the ingrowth of the surrounding tissue. The aim of the present study was to provide proof of these qualities in a xenograft model.

MATERIALS AND METHODS

A multilayer human AM (HAM) was applied to repair defined colon wall defects in Sprague-Dawley rats (n = 18). The control group was repaired with a suture (n = 6). The animals were killed humanely at 7, 21, and 42 days after implantation. Adhesions and perioperative complications were examined. Histological and immunohistological analyses were performed to assess a number of parameters, including degradation of the HAM, inflammation, graft rejection, and smooth muscle ingrowth.

RESULTS

Two rats in the treated group died. No other severe complications were observed. Adhesion formation was more prominently visible in the HAM group ( P < .05). The initially increased inflammation in the HAM group reduced over time but remained significantly increased ( P < .05). The HAM degraded over time and a subtle transient glomerulitis could be observed.

CONCLUSION

HAMs were found to increase adhesion formation and were not suitable for bowel augmentation in the presented xenograft model.

Effect of Human Amniotic Membrane on Prevention of Colorectal Anastomosis Leakage in Cases with Neoadjuvant Radiotherapy: An Experimental Animal Study

BACKGROUND

Radiotherapy is one of the most important factors which results in negative effects on wound healing and increases anastomosis leakage. Diverting loop ileostomy has been usually performed after colorectal anastomosis in cases of colorectal cancer with a history of neoadjuvant radiotherapy to decrease the chance of leakage. Considering the side effects of diverting loop ileostomy, the objective of the present study is to investigate the effect of human amniotic membrane (HAM) on colorectal anastomosis leakage after neo-adjuvant radiotherapy.

METHODS

In this experimental animal study, 20 crossbreed rabbits were randomly divided into two groups (case group: 13 rabbits, control group: 7 rabbits) after receiving an equal dose of external beam radiation. Four weeks after irradiation, resection of 4 cm of colorectal segment and end-to-end single layer anastomosis were conducted. In the case group, a 2×2 cm wrap of HAM applied around the site of anastomosis. Eight weeks later, all the survived rabbits were sacrificed. A segment of anastomotic sites was resected in all expired and survived rabbits and sent for pathological evaluation. Mann-Whitney U Test (SPSS for Windows, Ver. 16, Chicago, IL) was applied to analyze healing scores between the two groups.

RESULTS

Due to anastomosis dehiscence, 5 rabbits expired in the control group, but all the 13 rabbits (case group) survived after 8 weeks and showed no leakage. In addition, pathological evaluation revealed significant epithelialization and neovascularization in the case group. Statistically, healing score was higher in the case group rather than the control group (P<0.001).

CONCLUSION

To prevent post irradiation colorectal anastomosis leakage, the use of HAM might play a significant role and a feasible technical approach.

A light-activated amnion wrap strengthens colonic anastomosis and reduces peri-anastomotic adhesions

BACKGROUND AND OBJECTIVE

Colonic anastomotic failure is a dreaded complication, and multiple surgical techniques have failed to eliminate it. Photochemical tissue bonding (PTB) is a method of sealing tissue surfaces by light-activated crosslinking. We evaluated if a human amniotic membrane (HAM), sealed over the anastomotic line by PTB, increases the anastomotic strength.

STUDY DESIGN

Sprague-Dawley rats underwent midline laparotomy followed by surgical transection of the left colon. Animals were randomized to colonic anastomosis by one of the following methods (20 per group): single-layer continuous circumferential suture repair (SR); SR with a HAM wrap attached by suture (SR+ HAM-S); SR with HAM bonded photochemically over the anastomotic site using 532 nm light (SR+ HAM-PTB); approximation of the bowel ends with only three sutures and sealing with HAM-PTB (3+ HAM-PTB). A control group underwent laparotomy alone with no colon resection (NR). Sub-groups (n = 10) were sacrificed at days 3 and 7 post-operatively and adhesions were evaluated. A 6 cm section of colon was then removed and strength of anastomosis evaluated by burst pressure (BP) measurement.

RESULTS

A fourfold increase in BP was observed in the SR+ HAM-PTB group compared to suture repair alone (94 ± 3 vs. 25 ± 8 mm Hg, P < 0.0001) at day 3. At day 7 the burst pressures were 165 ± 40 and 145 ± 31 mm Hg (P = 1), respectively. A significant decrease in peri-anastomotic adhesions was observed in the SR+ HAM-PTB group compared to the SR group at both time points (P < 0.001).

CONCLUSION

Sealing sutured colonic anastomotic lines with HAM-PTB increases the early strength of the repair and reduces peri-anastomotic adhesions. Lasers Surg. Med. 48:530-537, 2016. © 2016 Wiley Periodicals, Inc.

Effect of the Human Amniotic Membrane on Liver Regeneration in Rats

Introduction. Operations are performed for broader liver surgery indications for a better understanding of hepatic anatomy/physiology and developments in operation technology. Surgery can cure some patients with liver metastasis of some tumors. Nevertheless, postoperative liver failure is the most feared complication causing mortality in patients who have undergone excision of a large liver mass. The human amniotic membrane has regenerative effects. Thus, we investigated the effects of the human amniotic membrane on regeneration of the resected liver. Methods. Twenty female Wistar albino rats were divided into control and experimental groups and underwent a 70% hepatectomy. The human amniotic membrane was placed over the residual liver in the experimental group. Relative liver weight, histopathological features, and biochemical parameters were assessed on postoperative day 3. Results. Total protein and albumin levels were significantly lower in the experimental group than in the control group. No difference in relative liver weight was observed between the groups. Hepatocyte mitotic count was significantly higher in the experimental group than in the control group. Hepatic steatosis was detected in the experimental group. Conclusion. Applying the amniotic membrane to residual liver adversely affected liver regeneration. However, mesenchymal stem cell research has the potential to accelerate liver regeneration investigations.

A new method to repair recto-vaginal fistula: Use of human amniotic membrane in an animal model

BACKGROUND

Recto-vaginal fistula is primarily one of the co-morbidities of vaginal delivery. These patients suffer from persistent malodor vaginal discharge. Various surgical techniques have been employed by surgeons in the course of time. This is the first trial of applying Human Amniotic Membrane (HAM) as a bio-prosthesis in repairing recto-vaginal fistula.

MATERIALS AND METHODS

In a prospective animal study, 8 mixed-breed female dogs weighing 23-27 kg with the age of 12-18 months were selected. They were randomly divided into two groups for standard recto-vaginal fistula repair and fistula repair with human amniotic membrane. The Kruskal-Wallis and Mann Whitney tests were performed to indicate statistical differences.

RESULTS

After 6 weeks, fistulas were evaluated both grossly and microscopically. In gross examination, there were no difference between the two groups and healing of fistula seemed to have been occurred in all dogs expect for one which had a persistent patent fistulous tract. Microscopic healing was scored according to epithelialization, collagenization inflammation, ulcer and necrosis of samples. Healing score was significantly higher in the HAM group than the standard group (P = 0.029).

CONCLUSION

Our findings revealed that using HAM as a bio-prosthesis to repair recto-vaginal fistula would result in better surgical and histological outcomes comparing to simple repair.

Evaluation of repair in duodenal perforation with human amniotic membrane: An animal model (dog)

Background:

There is a growing tendency toward application of human amniotic membrane (HAM) as a biologic substitute in various tissue injuries where a significant tissue loss is a matter of concern. In gastrointestinal injuries especially duodenal ones, some potential limitations in current surgical techniques contribute to not fully acceptable healing outcomes. Thus, this study was carried out to assess repair with HAM patch for duodenal defect in comparison with simple duodenoraphy in an animal model (dog).

Materials and Methods:

A total of 15 male German shepherd dogs weighing 23-27 kg were randomly divided into two groups. Group A with 10 dogs, which were a candidate for duodenal repair by amniotic membrane patch and Group B consisted of 5 dogs perform simple duodenorraphy. A precise control was made to match all conditions except surgical technique. Macroscopic and microscopic features of the healed duodenal lumen in both groups were recorded.

Results:

Gross evaluation revealed no difference in luminal diameter in both groups. Statistical analysis of duodenal diameter between both groups after operation also showed no significant difference (P_v = 0.789). Histological assessment indicated less inflammation with better wound healing in Group A.

Conclusion:

It seems that repairing duodenal wall defect with HAM would result in better histological outcomes compared with what is seen in simple duodenoraphy in animal models. However, there is no significant difference regarding surgical findings.

Sutureless primary repair of colonic perforation with a degradable stent in a porcine model of fecal peritonitis

PURPOSE

Colonic perforation with fecal peritonitis is a life-threatening clinical condition. For these patients, a two-stage operation of fecal diversion and a postponed colostomy closure is generally recommended. Accordingly, a simple and feasible primary repair technique was explored.

METHODS

A sutureless banding method using a biodegradable stent and a porcine model of artificial colonic perforation were introduced. The colonic perforation model was created successfully with an open procedure in 34 pigs. The primary repair with a stent or the conventional hand-sewn control was performed 72 h later. Morbidity and mortality were recorded. Pigs in each group were also sacrificed to evaluate the healing on postoperative days (PODs) 3, 7, 14, and 90. The peripheral white blood cell counts, albumin, anastomotic bursting pressure, hydroxyproline contents, and histology data were evaluated.

RESULTS

There were 17 pigs in either group. Four pigs (23.5 %) of the control group died, but no mortality occurred in the stent group. There were no significant differences in white blood cell counts and albumin. Though anastomotic hydroxyproline contents between the two groups were comparable, the collagen per protein ratio on POD 14 in the stent group was higher, as well as the bursting pressure on PODs 3 and 7. Microscopically, the local inflammation of the cut edges in the control group was more severe, and the collagen synthesis started later.

CONCLUSIONS

A sutureless primary repair of a colonic perforation with a degradable stent is a feasible method in a porcine model of fecal peritonitis.

Hyperbaric oxygen therapy and mechanical resistence of the colonics anastomosis in rats with peritonitis

PURPOSE

To analyze the effects of hyperbaric oxygen therapy (HBO) on the mechanical resistance of anastomosis performed in rats' distal colon presenting peritonitis induced by ligature and cecal punction using the Total Energy Rupture biomechanical test (ETR).

METHODS

It was used 45 rats divided into three groups of 15 animals each. In Control Group (CG), it was performed anastomosis in distal colon without peritonitis. In Peritonitis Group (PG), it was performed anastomosis six hours after the induction of peritonitis by ligature and cecal punction. In Hyperbaric Chamber Group (HCG), it was performed six hours after the induction of peritonitis by ligature and cecal punction. The animals on CG and PG were kept at place air while the animals on HCG were placed on an experimental hyperbaric chamber in order to inhale oxygen at 100%, two absolute atmospheres, for 120 minutes, for four consecutive days. Euthanasia took place on the fifth day of the experiment. All the animals underwent to Total Energy Rupture Biomechanical Resistance test (ETR). Total Energy Rupture was defined as the necessary internal energy stored up to promote the colon rupture after an external traction force imposition.

RESULTS

The Peritonitis Group presents smaller average ETR than Control Group. There was no statistical difference between Peritonitis Group and Hyberbaric Chamber Group.

CONCLUSION

Hyperbaric oxygen therapy did not alter the mechanical resistance of anastomosis performed in distal colon of rats under the presence of peritonitis induced by ligature and cecal puncture.

Covering the colon anastomoses with amniotic membrane prevents the negative effects of early intraperitoneal 5-FU administration on anastomotic healing

PURPOSE

This study investigated whether covering the colonic anastomoses with amniotic membrane (AM) protects the anastomotic healing from the adverse effects of immediate 5-fluorouracil (5-FU) administration.

METHODS

One hundred twenty wistar albino rats were randomized to one of four groups (I-IV, 30 rats in each) and underwent a standardized left colon resection and anastomoses. The anastomoses of the rats in groups II (AM) and IV (5-FU + AM) were covered with AM. Saline solution (2 ml/day; groups I (control) and II) or 5-FU (20 mg/kg/day; groups III (5-FU) and IV) was administered to the rats intraperitoneally once daily from the day of operation until sacrificed. Half of each group was sacrificed on the postoperative day 4 (IA, IIA, IIIA, and IVA) and other half on the postoperative day 8 (IB, IIB, IIIB, and IVB), and their anastomoses were evaluated when sacrificed.

RESULTS

The dehiscence rate of anastomotic dehiscence and adhesion formation were significantly higher in groups IIIA and IIIB compared with groups IVA and IVB, respectively. Bursting pressure was significantly higher in the 5-FU + AM groups than in the 5-FU groups. The inflammatory cell infiltration was significantly lower in groups IIIA and IVA compared with group IA, in groups IIIB and IVB compared with group IB, and in group IVA compared with group IIIA. Neoangiogenesis, fibroblast activity, collagen deposition, and hydroxyproline levels were significantly higher in the 5FU + AM groups compared with control and 5-FU groups. Malondialdehyde levels were significantly higher in the 5-FU groups than in the 5-FU + AM groups.

CONCLUSION

Covering colon anastomoses with AM protects them, preventing leakage and reversing the negative effects of 5-FU administration.