Yanay O, Moralejo D, Kernan K, Brzezinski M, Fuller JM, Barton R, Lernmark A, Osborne WR. Prolonged survival and improved glycemia in BioBreeding diabetic rats after early sustained exposure to glucagon-like peptide 1.
J Gene Med 2010;
12:538-44. [PMID:
20527046 PMCID:
PMC2882674 DOI:
10.1002/jgm.1466]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND
Type 1 diabetes (T1D) in both humans and BioBreeding (BB) rats is an autoimmune disease that results in complete destruction of islets and insulin dependency for life. Glucagon-like peptide 1 (GLP-1) promotes beta cell proliferation and neogenesis and has a potent insulinotropic effect. We hypothesized that the expression of GLP-1 before disease onset would increase islet mass, delay diabetes and prolong survival of BB rats.
METHODS
Vascular smooth muscle cells retrovirally transduced to secrete GLP-1 were seeded into TheraCyte encapsulation devices, implanted subcutaneously, and rats were monitored for diabetes.
RESULTS
In untreated control rats, plasma GLP-1 levels were 34.5-39.5 pmol/l, whereas, in treated rats, plasma levels were elevated, in the range 90-250.4 pmol/l. Hypoglycemia was not detected and this was anticipated from the glucose-regulated action of GLP-1. Diabetes onset (mean + or - SEM) in untreated rats occurred at 56.5 + or - 0.6 days (n = 6) and, in GLP-1-treated rats, was delayed until 76.4 + or - 3.3 days (n = 5) (p < 0.001). After disease onset, untreated control rats showed a rapid weight loss and elevated blood glucose (>650 mg/dl) and did not survive beyond 11 days. At 5 days after diabetes onset, insulin-secreting islets were absent in untreated rats. By contrast, treated rats maintained weight for up to 143 days of age and showed insulin-secreting beta cells.
CONCLUSIONS
Sustained GLP-1 expression delivered by encapsulated cells before diabetes onset in BB rats showed an improved clinical outcome, suggesting the potential for treating patients using long lasting GLP-1 analogs.
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