Lipid-Mediated Transbronchial Human Interleukin-10 Gene Transfer Decreases Acute Inflammation Associated With Allograft Rejection in a Rat Model of Lung Transplantation

Transbronchial human interleukin-10 gene transfer reduces acute inflammation associated with allograft rejection and intragraft interleukin-2 and tumor necrosis factor-alpha gene expression in a rat model of lung transplantation

BACKGROUND

The ability to express genes with potential immunoregulatory capacity could reduce allograft rejection (AR). This study examined the effect of ex vivo lipid-mediated transbronchial human interleukin-10 (hIL-10) gene transfer on AR and the intragraft cytokine profile in a rat model of lung transplantation.

METHODS

Left single lung transplants were performed between a highly histoincompatible combination of inbred rats. The donor left lung was extracted and intrabronchially instilled with a plasmid encoding hIL-10 (IL-10 group) or Escherichia coli beta-galactosidase (control group), mixed with a cationic lipid. At 3 and 6 days after transplantation, the degree of AR was graded histologically (stage 1-4) and several pathologic categories of inflammation were scored on a scale of 0 to 4 according to the percentage of involvement. Intragraft cytokine profile was examined by real-time reverse transcription polymerase chain reaction.

RESULTS

The stage of AR (3.1 +/- 0.4 vs 3.8 +/- 0.4) and the pathologic scores for edema (2.3 +/- 0.8 vs 3.2 +/- 0.4), intraalveolar hemorrhage (0.3 +/- 0.5 vs 2.2 +/- 0.8), and necrosis (0.3 +/- 0.5 vs 1.2 +/- 0.4) in the IL-10 group were significantly decreased compared with the control group at Day 6. IL-2 and tumor necrosis factor-alpha messenger RNA expression levels on Day 3 were significantly decreased in the IL-10 group.

CONCLUSIONS

Ex vivo lipid-mediated transbronchial hIL-10 gene transfer attenuated acute inflammation associated with AR, which was related to decreased levels of proinflammatory cytokine gene expression in a rat model of lung transplantation.

PPARalpha ligand WY14643 reduced acute rejection after rat lung transplantation with the upregulation of IL-4, IL-10 and TGFbeta mRNA expression

BACKGROUND

The peroxisome proliferators-activated receptor-alpha (PPARalpha) is important in lipid metabolism and regulation of inflammation. Recent studies have demonstrated the immunoregulatory effects of PPARalpha. This investigated the immunosuppressive effects of PPARalpha using its ligand, WY14643, on acute lung allograft rejection in a rat model and its mechanism of action.

METHOD

The left lungs were transplanted orthotopically from Brown-Norway donors to F344 recipients. The recipients were then divided into control and WY14643 treatment groups. The allograft rejection was evaluated by daily chest X-ray imaging and was evaluated histologically on Day 7 after transplantation. The cytokine messenger RNA (mRNA) expression at Days 3 and 5 were also evaluated in allografts and recipient spleens.

RESULTS

The radiologic and histologic findings indicated that treatment with the WY14643 reduced acute allograft rejection. WY14643 also significantly extended the allograft survival time. This amelioration of acute rejection by WY14643 was also associated with up-regulated interleukin (IL)-4, IL-10, and transforming growth factor-beta (TGFbeta) mRNA expression in the lung allografts and spleens.

CONCLUSION

This study demonstrated that the administration of the PPARa ligand, WY14643, ameliorates acute lung allograft rejection in rats. Treatment with WY14643 reduced histopathologic scores, prolonged graft survival, and up-regulated the expression of anti-inflammatory cytokine IL-4, IL-10, and TGFbeta mRNA compared with the control.