Regeneration of pancreatic islets in vivo by ultrasound-targeted gene therapy.
This study uses a novel approach to gene therapy in which plasmid DNA is targeted to the pancreas in vivo using ultrasound-targeted microbubble destruction (UTMD) to achieve islet regeneration. Intravenous microbubbles carrying plasmids are destroyed within the pancreatic microcirculation by ultrasound, achieving local gene expression that is further targeted to β-cells by a modified rat insulin promoter (RIP3.1). A series of genes implicated in endocrine development were delivered to rats 2 days after streptozotocin-induced diabetes. The genes, PAX4, Nkx2.2, Nkx6.1, Ngn3 and Mafa, produced α-cell hyperplasia, but no significant improvement in β-cell mass or blood glucose level 30 days after UTMD. In contrast, RIP3.1-NeuroD1 promoted islet regeneration from surviving β-cells, with normalization of glucose, insulin and C-peptide levels at 30 days. In a longer-term experiment, four of six rats had a return of diabetes at 90 days, accompanied by β-cell apoptosis on Tunel staining. Pretreatment with the JNK inhibitor SP600125 successfully blocked β-cell apoptosis and resulted in restoration of β-cell mass and normalization of blood glucose level for up to 90 days. This technique allows in vivo islet regeneration, restoration of β-cell mass and normalization of blood sugar, insulin and C-peptide in rats without viruses.
Baylor Research Institute, Baylor University Medical Center, Dallas, TX 75226, USA.
S
S
Chen
M
M
Shimoda
M-Y
MY
Wang
J
J
Ding
H
H
Noguchi
S
S
Matsumoto
P A
PA
Grayburn
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000032:analysis; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000628:therapy*; D017930:Genes, Reporter / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods*; D000090322:Homeobox Protein Nkx-2.2; D007328:Insulin / Q000097:blood / Q000235:genetics / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000378:metabolism; D007515:Islets of Langerhans / Q000502:physiology*; D008297:Male; D045423:Microbubbles / Q000627:therapeutic use; D011401:Promoter Regions, Genetic; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration; D014464:Ultrasonic Therapy / Q000379:methods*
D001786:Blood Glucose; D002096:C-Peptide; D000090322:Homeobox Protein Nkx-2.2; D007328:Insulin; C000715628:Nkx2-2 protein, rat