Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

PREVENTION OF POSTSURGICAL ABDOMINAL ADHESIONS BY POLYPEPTIDES

Nehéz, Laszlo LU (2006)
Abstract
Peritoneal adhesions develop after almost all abdominal surgical interventions and represent an important cause of postoperative intestinal obstruction, abdominal discomfort and infertility. Postoperative adhesions can potentially be reduced by using different antiadhesive agents. In the present study, we hypothesized that a combination of oppositely charged polypeptides could effectively decrease abdominal adhesions.



Various polypeptides, including lysozyme, polyglutamate, polylysine and combinations of these were evaluated as compared to hyaluronic acid. A standard wound on the parietal peritoneum in mice was used and the evaluated agents were administered immediately postoperatively. The length of the peritoneal... (More)
Peritoneal adhesions develop after almost all abdominal surgical interventions and represent an important cause of postoperative intestinal obstruction, abdominal discomfort and infertility. Postoperative adhesions can potentially be reduced by using different antiadhesive agents. In the present study, we hypothesized that a combination of oppositely charged polypeptides could effectively decrease abdominal adhesions.



Various polypeptides, including lysozyme, polyglutamate, polylysine and combinations of these were evaluated as compared to hyaluronic acid. A standard wound on the parietal peritoneum in mice was used and the evaluated agents were administered immediately postoperatively. The length of the peritoneal adhesions to the injured area was measured and expressed in percentage of the wound length as evaluated after 7 days. Flow cytometry was performed to evaluate the effect on peritoneal macrophage survival and phagocytic function and Pick test was used to determine peroxide production in order to estimate toxicity and potential impairment of macrophage function. Peritoneal swabs, including the wound area, were stained in order to determine the peritoneal location and clearance of the polypeptides. Electron microscopy was performed to analyze the wound surface and the ultra-structural changes of the phagocytes in cell culture. A reduced dose of polylysine and polyglutamate and local application on the injured peritoneal site were tested prior to the use of polyarginine, representing a potential alternative to polylysine. An ileocolic anastomosis was performed under both ?clean? and ?septic? conditions in the rat. In the presence of tested polypeptides, abdominal adhesions, anastomosis leakage and burst pressure were analysed after 1, 3, 5 and 7 days in the clean anastomosis model and after 7 days in the septic model.



The combination of polylysine and polyglutamate significantly reduced postsurgical peritoneal adhesions in all experimental groups. This combination was biodegradable and did not alter the basic functions of peritoneal macrophages and showed no direct cytotoxicity. The insoluble test material specifically adhered to the injured peritoneum, and increased colonic anastomosis safety during the first postoperative days.



In conclusion, a strong mechanical connection of the polylysine and polyglutamate complex occurred to the wound, and by prolonged attendance on the surface resulted in an effective prevention against peritoneal adhesions. (Less)
Abstract (Swedish)
Popular Abstract in Swedish

Sammanväxningar i buken utvecklas efter flertalet kirurgiska bukingrepp och utgör en betydande orsak till tarmvred, buksmärta och infertilitet. Buksammanväxningar skulle potentiellt kunna minskas i omfattning med användande av förebyggande behandling men här finns klara begränsningar i exempelvis effekt och ett stort utrymme för förbättring. De i denna avhandling ingående studierna har utvärderat effekten av olikladdade polypeptider givna i bukhålan i syfte att minska sammanväxningar. Hypotesen var att en kombination av olikladdade polypeptider, som resulterar i ett låglösligt komplex, effektivt skulle minska buksammanväxningar. Vi menar att poly-L-glutamat (pG) och poly-L-lysin (pL) kan utgöra... (More)
Popular Abstract in Swedish

Sammanväxningar i buken utvecklas efter flertalet kirurgiska bukingrepp och utgör en betydande orsak till tarmvred, buksmärta och infertilitet. Buksammanväxningar skulle potentiellt kunna minskas i omfattning med användande av förebyggande behandling men här finns klara begränsningar i exempelvis effekt och ett stort utrymme för förbättring. De i denna avhandling ingående studierna har utvärderat effekten av olikladdade polypeptider givna i bukhålan i syfte att minska sammanväxningar. Hypotesen var att en kombination av olikladdade polypeptider, som resulterar i ett låglösligt komplex, effektivt skulle minska buksammanväxningar. Vi menar att poly-L-glutamat (pG) och poly-L-lysin (pL) kan utgöra en sådan möjlig framtida effektiv förebyggande behandling av buksammanväxningar. Inverkan på normalt förekommande vita blodkroppar i bukhålan och läkning av samtidigt utförd tarmanastomos har studerats. Dessutom studerades olika doser av polypeptiderna och olika administrations-sätt. Alternativa kombinationer till pL och pG testades.



Olika polypeptider, inkluderande lysosym, pG, pL och kombinationer av dessa utvärderades mot hyaluronsyra (som användes i kommersiellt tillgängliga preparat idag). En standardiserad skada på bukhinnan gjordes på möss och de olika substanserna gavs i omedelbar anslutning till operationens avslutande. Längden av sammanväxningar mot bukhinnedefekten mättes och uttrycktes i procent av totala längden efter sju dagar. Med s k flödescytometri utvärderades effekten på makrofager (vita blodceller) i bukhålan och deras överlevnad respektive upptagsförmåga (fagocytos) i syfte att göra en utvärdering av eventuell negativ inverkan av polypeptidkombinationen. Morfo-logiska (vävnadsbilder) studier gjordes på såret och dess läkning över tiden. Olika doser av de substanser som befanns mest gynnsamma i kombination (pL+pG) studerades liksom enbart lokal behandling mot enbart den skadade ytan på bukhinnan. Dessutom studerades inverkan av polypeptiderna på samtidigt utförd tarmanastomos (då hyaluronsyra rapporterats ha negativ inverkan på tarmläkningen) liksom hur effekten var beträffande motverkan av buksammanväxningar vid samtidigt förekommande infektion i bukhålan.



Kombinationen pL och pG minskade signifikant mängden buksammanväx-ningar. Det visade sig att komplexet var nedbrytbart och inte påverkade funktionen hos bukhålemakrofager och att polypeptidkomplexet specifikt fastnade på enbart det skadade bukhinneområdet. Samtidigt sågs också att hållfastheten i gjord tarmanastomos ökade under de första dagarna efter operation.



Sammanfattningsvis fann vi en stark mekanisk bindning av komplexet pL och pG till ett standardiserat bukhinnesår och denna bindning var utsträckt över tiden med en gradvis nedbrytning och ersättande av normal vävnad samtidigt som man inte såg någon negativ effekt på funktionen av bukhålemakrofager. Fortsatta studier får utvärdera konceptets betydelse och eventuella kliniska värde. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor van Gulik, Thomas, Academic Medical Center, Amsterdam, The Netherlands
organization
publishing date
type
Thesis
publication status
published
subject
keywords
traumatology, Surgery, orthopaedics, poly-L-glutamate, anastomotic healing, peritoneum, adhesion, prevention, poly-L-lysine, traumatologi, Kirurgi, ortopedi, polypeptides, surgery
pages
103 pages
publisher
Department of Surgery, Clinical Sciences Lund, Lund University
defense location
Lecture room 1, Ground floor, Central Building, Lund University Hospital
defense date
2006-12-21 13:00:00
ISBN
91-85559-69-5
language
English
LU publication?
yes
additional info
id
7b911a12-688e-4ec8-baf9-fb1d1955e13b (old id 547749)
date added to LUP
2016-04-01 15:20:21
date last changed
2018-11-21 20:33:56
@phdthesis{7b911a12-688e-4ec8-baf9-fb1d1955e13b,
  abstract     = {Peritoneal adhesions develop after almost all abdominal surgical interventions and represent an important cause of postoperative intestinal obstruction, abdominal discomfort and infertility. Postoperative adhesions can potentially be reduced by using different antiadhesive agents. In the present study, we hypothesized that a combination of oppositely charged polypeptides could effectively decrease abdominal adhesions.<br/><br>
<br/><br>
Various polypeptides, including lysozyme, polyglutamate, polylysine and combinations of these were evaluated as compared to hyaluronic acid. A standard wound on the parietal peritoneum in mice was used and the evaluated agents were administered immediately postoperatively. The length of the peritoneal adhesions to the injured area was measured and expressed in percentage of the wound length as evaluated after 7 days. Flow cytometry was performed to evaluate the effect on peritoneal macrophage survival and phagocytic function and Pick test was used to determine peroxide production in order to estimate toxicity and potential impairment of macrophage function. Peritoneal swabs, including the wound area, were stained in order to determine the peritoneal location and clearance of the polypeptides. Electron microscopy was performed to analyze the wound surface and the ultra-structural changes of the phagocytes in cell culture. A reduced dose of polylysine and polyglutamate and local application on the injured peritoneal site were tested prior to the use of polyarginine, representing a potential alternative to polylysine. An ileocolic anastomosis was performed under both ?clean? and ?septic? conditions in the rat. In the presence of tested polypeptides, abdominal adhesions, anastomosis leakage and burst pressure were analysed after 1, 3, 5 and 7 days in the clean anastomosis model and after 7 days in the septic model.<br/><br>
<br/><br>
The combination of polylysine and polyglutamate significantly reduced postsurgical peritoneal adhesions in all experimental groups. This combination was biodegradable and did not alter the basic functions of peritoneal macrophages and showed no direct cytotoxicity. The insoluble test material specifically adhered to the injured peritoneum, and increased colonic anastomosis safety during the first postoperative days.<br/><br>
<br/><br>
In conclusion, a strong mechanical connection of the polylysine and polyglutamate complex occurred to the wound, and by prolonged attendance on the surface resulted in an effective prevention against peritoneal adhesions.},
  author       = {Nehéz, Laszlo},
  isbn         = {91-85559-69-5},
  language     = {eng},
  publisher    = {Department of Surgery, Clinical Sciences Lund, Lund University},
  school       = {Lund University},
  title        = {PREVENTION OF POSTSURGICAL ABDOMINAL ADHESIONS BY POLYPEPTIDES},
  year         = {2006},
}