In the in vivo studies, it was found that administration of PAR1 antagonists RWJ56110 (1 mg/kg) and PAR2 antagonist FSLLRY-NH2 (1 mg/kg) significantly attenuated the hypertrophic effects of intra-cardiac Ad-KLK8 gene delivery, as evidenced by the decreases in the transcripts of cardiac hypertrophy markers (Fig. 11A–C) and cross-sectional area of cardiomyocytes (Fig. 11D,E) as compared with those obtained from rats injected with Ad-KLK8 alone. The gene discussed is F2R; the disease is cardiac hypertrophy.