Efficient and persistent transduction of exocrine and endocrine pancreas by adeno-associated virus type 8.

Efficient delivery of therapeutic proteins into the pancreas represents a major obstacle to gene therapy of pancreatic disorders. The current study compared the efficiency of recombinant lentivirus and adeno-associated virus (AAV) serotypes 1, 2, 5, 8 vectors delivered by intrapancreatic injection for gene transfer in vivo. Our results indicate that lentivirus and AAV 1, 2, 8 are capable of transducing pancreas with the order of efficiency AAV8 >>AAV1 > AAV2 >/= lentivirus, whereas AAV5 was ineffective. AAV8 resulted in an efficient, persistent (150 days) and dose-dependent transduction in exocrine acinar cells and endocrine islet cells. Pancreatic ducts and blood vessels were also transduced. Extrapancreatic transduction was restricted to liver. Leukocyte infiltration was not observed in pancreas and blood glucose levels were not altered. Thus, AAV8 represents a safe and effective vehicle for therapeutic gene transfer to pancreas in vivo.

Specific beta1-adrenergic receptor silencing with small interfering RNA lowers high blood pressure and improves cardiac function in myocardial ischemia.

OBJECTIVES: Beta-blockers are widely used and effective for treating hypertension, acute myocardial infarction (MI) and heart failure, but they present side-effects mainly due to antagonism of beta2-adrenergic receptor (AR). Currently available beta-blockers are at best selective but not specific for beta1 or beta2-AR. METHODS: To specifically inhibit the expression of the beta1-AR, we developed a small interfering RNA (siRNA) targeted to beta1-AR. Three different sequences of beta1 siRNA were delivered into C6-2B cells with 90% efficiency. RESULTS: One of the three sequences reduced the level of beta1-AR mRNA by 70%. The siRNA was highly specific for beta1-AR inhibition with no overlap with beta2-AR. To test this in vivo, systemic injection of beta1 siRNA complexed with liposomes resulted in efficient delivery into the heart, lung, kidney and liver, and effectively reduced beta1-AR expression in the heart without altering beta2-AR. beta1 siRNA significantly lowered blood pressure of spontaneously hypertensive rats (SHR) for at least 12 days and reduced cardiac hypertrophy following a single injection. Pretreatment with beta1 siRNA 3 days before induction of MI in Wistar rats significantly improved cardiac function, as demonstrated by dP/dt and electrocardiogram following the MI. The protective mechanism involved reduction of cardiomyocyte apoptosis in the beta1 siRNA-treated hearts. CONCLUSIONS: The present study demonstrates the possibility of using siRNA for treating cardiovascular diseases and may represent a novel beta-blocker specific for beta1-AR.