Safety and efficacy of adeno-associated viral vector-mediated insulin gene transfer via portal vein to the livers of streptozotocin-induced diabetic Sprague-Dawley rats.
BACKGROUND
Previous studies demonstrating the efficacy of insulin gene therapy have mostly involved use of adenoviral vectors or naked DNA to deliver the insulin gene. However, this procedure may not guarantee long-term insulin production. To improve the performance, we prepared recombinant adeno-associated viral vectors (rAAV) harboring the gene encoding a furin-modified human insulin under the cytomegalovirus (CMV) promoter [rAAV-hPPI(F12)].


METHODS
Streptozotocin (STZ)-induced diabetic Sprague-Dawley rats were used as a diabetic animal model. The levels of blood glucose, insulin, and HbA1c were measured to test the effect. An intraperitoneal glucose tolerance test was performed to test the capability of blood glucose disposal. Immunohistochemical staining and Northern blot analyses were performed to survey the expression pattern of the therapeutic insulin gene.


RESULTS
STZ-induced diabetic Sprague-Dawley rats infused via the portal vein with rAAV-hPPI(F12) produced human insulin and after a 6-h fast were normoglycemic for over 90 days post-treatment, whereas diabetic rats treated with recombinant adenoviral vector harboring the hPPI(F12) gene [rAV-hPPI(F12)] were normoglycemic only for days 3 to 13 post-treatment. Insulin mRNA was detected mainly in the liver of the rAAV-hPPI(F12)-treated diabetic rats. The glucose tolerance capability of the rAAV-hPPI(F12)-treated diabetic rats was comparable to that of non-diabetic rats, even without injection of recombinant insulin. Furthermore, blood HbA1c concentrations in rAAV-hPPI(F12)-treated diabetic rats were reduced to almost the normal level. Importantly, studies of rAV or rAAV vector-dependent side effects on the targeted liver strongly suggested that only rAAV treatment caused no side effects.


CONCLUSIONS
These results demonstrate that our rAAV-mediated in vivo insulin gene therapy provides safer maintenance of the insulin gene expression required for long-term and thus more effective blood glycemic control.
Park
Young Mi
YM
Brain Korea 21 Project for Medical Science, College of Medicine, Yonsei University, Seoul 120-752, Korea.
Woo
Seonock
S
Lee
Geun Taek
GT
Ko
Ji-Yun
JY
Lee
Yongho
Y
Zhao
Zheng-Shan
ZS
Kim
Hye Joo
HJ
Ahn
Chul Woo
CW
Cha
Bong Soo
BS
Kim
Kyung-Sup
KS
Park
Cheol Won
CW
Lee
Hyun Chul
HC
D000818:Animals; D030801:Animals, Genetically Modified; D001786:Blood Glucose / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000494:pharmacology; D000229:Dependovirus / Q000235:genetics*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism / Q000628:therapy*; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism; D007328:Insulin / Q000235:genetics* / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D011169:Portal Vein; D011384:Proinsulin / Q000378:metabolism; D000071198:Pyrin; D051381:Rats; D017207:Rats, Sprague-Dawley; D012449:Safety; D016896:Treatment Outcome
D001786:Blood Glucose; D003598:Cytoskeletal Proteins; D006442:Glycated Hemoglobin; D007328:Insulin; D011384:Proinsulin; D000071198:Pyrin