The ICAM-1 antisense oligonucleotide ISIS-3082 prevents the development of postoperative ileus in mice

Abstract

Intestinal manipulation (IM) during abdominal surgery triggers the influx of inflammatory cells, leading to postoperative ileus. Prevention of this local muscle inflammation, using intercellular adhesion molecule-1 (ICAM-1) and leukocyte function-associated antigen-1-specific antibodies, has been shown to shorten postoperative ileus. However, the therapeutic use of antibodies has considerable disadvantages. The aim of the current study was to evaluate the effect of ISIS-3082, a mouse-specific ICAM-1 antisense oligonucleotide, on postoperative ileus in mice. Mice underwent a laparotomy or a laparotomy combined with IM after treatment with ICAM-1 antibodies, 0.1-10 mg kg(-1) ISIS-3082, saline or ISIS-8997 (scrambled control antisense oligonucleotides, 1 and 3 mg kg(-1)). At 24 h after surgery, gastric emptying of a 99mTC labelled semi-liquid meal was determined using scintigraphy. Intestinal inflammation was assessed by myeloperoxidase (MPO) activity in ileal muscle whole mounts. IM significantly reduced gastric emptying compared to laparotomy. Pretreatment with ISIS-3082 (0.1-1 mg kg(-1)) as well as ICAM-1 antibodies (10 mg kg(-1)), but not ISIS-8997 or saline, improved gastric emptying in a dose-dependent manner. This effect diminished with higher doses of ISIS-3082 (3-10 mg kg(-1)). Similarly, ISIS-3082 (0.1-1 mg kg(-1)) and ICAM-1 antibodies, but not ISIS-8997 or higher doses of ISIS-3082 (3-10 mg kg(-1)), reduced manipulation-induced inflammation. Immunohistochemistry showed reduction of ICAM-1 expression with ISIS-3082 only. ISIS-3082 pretreatment prevents postoperative ileus in mice by reduction of manipulation-induced local intestinal muscle inflammation. Our data suggest that targeting ICAM-1 using antisense oligonucleotides may represent a new therapeutic approach to the prevention of postoperative ileus.

Figure 1

Effect of IM on gastric retention 24 h after abdominal surgery compared to laparotomy only (L), or IM after treatment with ICAM-1 antibodies (anti-CD54 IgG2b clone 1/1.7). Each individual group consisted of eight animals. Data are mean±s.e.m. gastric retention 80 min after gavage of semi-liquid test meal; ^*P<0.05 compared to L control; ^**P<0.05 compared to IM control.

Figure 2

Effect of IM, laparotomy only (L) or IM pretreated with ICAM-1 antibodies (anti-CD54 IgG2b clone 1/1.7) on local inflammatory cell influx 24 h after abdominal surgery. Each individual group consisted of eight animals. Data are mean±s.e.m. number of MPO-positive cells mm⁻²; ^*P<0.05 compared to L control; ^**P<0.05 compared to IM control.

Figure 3

Effect of ISIS-3082, ISIS-8997 or vehicle on gastric retention 24 h after laparotomy (L) or laparotomy with IM. Each individual group consisted of eight animals. Data are mean±s.e.m. gastric retention 80 min after gavage of semi-liquid test meal; ^*P<0.05 compared to L control; ^**P<0.05 compared to vehicle IM control.

Figure 4

Effect of ISIS-3082, ISIS-8997 or vehicle on local inflammatory cell influx 24 h after laparotomy (L) or laparotomy with IM. Each individual group consisted of eight animals. Data are mean±s.e.m. number of MPO-positive cells mm⁻²; ^*P<0.05 compared to L control; ^**P<0.05 compared to vehicle IM control.

Figure 5

MPO staining of muscle whole mounts from mice that underwent a laparotomy after pretreatment with saline (a), or a laparotomy with intestinal manipulation after pretreatment with saline (b), ICAM-1 antibodies (10 mg kg⁻¹) (c), 1 mg kg⁻¹ ISIS-3082 (d), 10 mg kg⁻¹ ISIS-3082 (e) or 1 mg kg⁻¹ ISIS-8997 (f). Magnification × 20; insertion × 65.

Figure 6

ICAM-1 staining of ileal transverse segments from mice pretreated with saline that underwent a laparotomy (a), and from mice that underwent a laparotomy with IM after pretreatment with saline (b), 1 mg kg⁻¹ ISIS-3082 (c), 10 mg kg⁻¹ ISIS-ISIS-3082 (d) or 1 mg kg⁻¹ ISIS-8997 (e). Note the increased ICAM-1 expression in the densely vascularised submucosa, but also in the blood vessels, visible in the muscularis propria after IM (arrow heads). Only pretreatment with 1 mg kg⁻¹ ISIS-3082 reduces the ICAM-1 expression (c).