Modified Adenovirus Reduces De Novo Peritoneal Adhesions in Rats and Limits Off-Target Transfection. Role of EZH2 in Adhesion Formation

ABSTRACT

Aim of the study: Adenovector encoding tissue plasminogen activator (tPA) was shown to reduce experimental peritoneal adhesion. We investigated the targeting potential of our modified adenovector, its ability to reduce adhesions and the epigenetic role of histone methyltransferase EZH2 in adhesion formation. Materials and methods: Control lacZ, nonmodified tPA or modified tPA vectors were instilled in the peritoneal cavity after injury in de novo adhesions or after lysis of adhesions in recurrent adhesions. Adhesion severity was scored and adhesions and liver tissues were examined for adenovirus E4 gene and tPA mRNA expression. Levels of tPA, plasminogen activator inhibitor-1 (PAI-1), transforming growth factor-β1 (TGF-β1), and EZH2 expression were measured. Results: E4 transcripts were detected in adhesions of nonmodified and modified and in livers of nonmodified but not in livers of modified de novo adhesions. Both nonmodified (p = 0.021) and modified vectors (p = 0.036) reduced the severity of de novo adhesions compared to lacZ vector. Levels of tPA in nonmodified (p = 0.021) and modified adhesions (p = 0.001) were elevated while PAI-1 (p = 0.013 and p = 0.001, respectively) and TGF-β1 levels (p = 0.002 and p = 0.016, respectively) were reduced compared with lacZ group. All vectors were not expressed in recurrent adhesions and severity score were not different among groups. EZH2 levels were elevated in de novo nontreated (p = 0.001) and was further increased in recurrent (p = 0.001) nontreated adhesions compared with noninjured peritoneum. Conclusion: Modified adenovirus successfully targeted de novo adhesions but not liver tissues and reduced the severity of de novo adhesions. EZH2 is involved in the development and progression of peritoneal adhesions.

Keywords::

• peritoneal adhesions
• gene therapy
• tissue plasminogen activator
• plasminogen activator inhibitor-1
• transforming growth factor beta-1
• histone methyltransferase

Declaration of interest: All authors have read the journal's policy on disclosure of potential conflicts of interest. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

FUNDING

This work is supported by a grant from the Egyptian Science and Technology Development Fund (739/2010) to Dr. Hussein Atta. The funding source has no role in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.

AUTHOR CONTRIBUTIONS

• Conceived the idea: HM Atta, AA Al-Hendy

• Vector construction: AA Al-Hendy, HM Atta

• Surgical procedure: HM Atta

• Biochemical analyses and acquisition of data: SR Abdel Raheim, H Abdel-Ghany, KA Nasif, AM Abdellah, NM Zenhom, HS Kamel

• Statistical analysis: HM Atta

• Analysis and interpretation of data, manuscript preparation and final approval of the version to be submitted: HM Atta, AA Al-Hendy, SR Abdel Raheim, H Abdel-Ghany, KA Nasif, AM Abdellah, NM Zenhom, HS Kamel

• Obtained fund: HM Atta, AA Al-Hendy