27. Prevention of Cardiac Remodeling and Heart Failure in Dahl-Salt Sensitive Rats by AAV Vector-Mediated Interleukin-10 Expression
Authors: Mutsuko Sarukawa, Takashi Okada, Toru Yoshioka, Takayuki Ito, Tatsuya Nomoto, Hiroaki Mizukami, Akihiro Kume, Keiji Yamamoto, Uichi Ikeda, Kazuyuki Shimada, Keiya Ozawa
Journal: Molecular Therapy (2006)

Background: Inflammation plays a crucial role in the pathogenesis of congestive heart failure (CHF). Enhanced plasma levels of proinflammatory cytokines in patients with CHF have been demonstrated by many other groups. TNF-α targeted approach was not sufficient to disrupt the activated network of inflammatory mediators in CHF. IL-10 exerts pleiotropic cardioprotective effects, such as anti-inflammatory effect, and improvement of the endothelial cell function. Previously, we reported that systemic expression of IL-10 ameliorated hypertension as well as cardiac hypertrophy in the Dahl salt-sensitive (DS) rats. In this study, we further investigated LV systolic function and remodeling to examine the preventive effects of IL-10 on CHF in the DS rats. Methods: We constructed AAV type 1-based vectors that express rat IL-10 (AAV1-IL-10) or EGFP (AAV1-EGFP) driven by the CAG promoter. The DS rats were intramuscularly injected with the vector (1 × 10 12 genome copies/body, n=10 each) at 5 weeks old. Systolic blood pressure (sBP) was measured by the tail-cuff method every 2 weeks. Transthoracic echocardiography was performed at 5, 11, and 19 weeks old. At 20 weeks old, heart tissue was examined under the light microscope following H&E, Azan-Mallory staining, and immunohistochemistry for ED-1. Results: Six weeks after single intramuscular injection of the vectors, the serum concentration of IL-10 significantly increased in the IL-10-transduced group compared to that in the EGFP-transduced group (418 vs. 0 pg/ml, p<0.0001). TNF-α concentrations in serum and TGF-β 1 levels in the heart decreased at 20 weeks old in the IL-10-transduced group (0 vs. 7.1 pg/ml, p<0.005; 63.5 vs. 174.3 pg/mg protein, p<0.05). Four weeks after injection of the vectors, sBP of the IL-10-transduced group significantly decreased compared to that of the EGFP-transduced group. This sBP reduction persisted over 2 months (at 18 weeks old; 175 vs. 231 mmHg, p<0.0001). At CHF phase (19 weeks old), LV systolic dysfunction (percent fractional shortening; 59.2 vs. 32.9, p<0.0001) and LV dilatation (LV end-diastolic dimension; 7.3 vs. 8.8 mm, p<0.0001) improved in the IL-10-transduced group. Importantly, histological examination revealed that fibrotic changes and macrophage infiltration significantly increased in the heart of the GFP-transduced group. However, these cardiac remodeling were abolished in the IL-10-transduced group. Furthermore, survival rate also improved at 20 weeks old in the IL-10-transduced group (100 vs. 0%). Conclusion: AAV vector-mediated systemic expression of IL-10 in the DS rats effectively improved inflammation, hypertension, and CHF. Protein supplementation therapy through AAV vector- mediated systemic IL-10 expression would be a promising strategy to prevent the development of cardiac remodeling and CHF in patients with genetic predisposition.