INVESTIGADORES
BIANCHI Maria Silvia
congresos y reuniones científicas
Título:
Effect of oligonucleotide IMT504 in a type I diabetes model induced by multiple low doses of Streptozotocin in mice
Autor/es:
BIANCHI MS; CALVO V; CHASSEING NA; LIBERTUN C; MONTANER A; LUX-LANTOS V
Lugar:
Boston, MA
Reunión:
Congreso; The Endocrine Society (USA). 93th Annual Meeting & Expo; 2011
Institución organizadora:
The Endocrine Society (USA)
Resumen:
IMT504, the prototype of
the PyNTTTTGT class of oligonucleotides, stimulates mesenchymal stem cells both
in vitro and in vivo (1). We have shown that the oligonucleotide IMT504 induces a marked
recovery of single-dose streptozotocin (STZ)-induced toxic diabetes in male
rats that correlates with early expression of progenitor cell markers (2). Here, we evaluated the effect of IMT504 on a type I diabetes model
induced by multiple low doses of STZ in mice.
Male Balb/C mice (6-8 week-old) were injected
with STZ ip (40mg/kg, diluted in citrate buffer) daily for 5 consecutive days or with citrate buffer
as control (C). Normal glycemia (Gly) in the fed condition was 149±13 mg/dl. Animals which developed Gly levels ³ 250 mg/dl were considered diabetics and injected daily with IMT504 doses
(20mg/kg/day, sc) for 10 days (STZ-IMT) or saline as control (STZ) (day 1). Another
5 doses of IMT504 starting on days 21 and 36 were then administrated. A group
of C mice were injected with the same IMT doses (C-IMT).Body weight was
recorded and Gly was measured for a total of 66 days. At the end of the experiment,
glucose tolerance tests (GTT) were performed (2g/kg BW glucose was injected ip,
and glucose determined in tail blood samples). Four days later fasted
animals were sacrificed, blood samples and pancreases collected for hormonal
determinations and histological studies respectively.
We observed that 20% of STZ mice (2/10) showed
spontaneous reversion of the diabetic condition whereas IMT treatment induced a
marked blood glucose decrease in 88% of STZ-IMT-treated
mice (7/8) [day 66= Gly (mg/dl): C: 130±9 (n=6) vs STZ-IMT:
278±46, p<0.01, STZ-IMT vs STZ: 557±20, p<0.01]. GTTs showed a partial
recovery in the STZ-IMT responsiveness [ANOVA: p<0.001, 0
min= C: 117±11, STZ-IMT: 164±9, STZ: 309±53, STZ vs C and STZ-IMT: p<0.02;
30 min= C: 292±51, STZ-IMT: 342±33, STZ: 488±36, C vs STZ: p<0.02; 120
min C: 133±15, STZ-IMT: 352±28, STZ: 472±52, C vs STZ and vs STZ-IMT: p<0.02]. Regarding
body weight, IMT promoted a transient decrease in STZ mice. Besides IMT improved
beta cell function in diabetic animals [HOMA beta cell= C: 66±29, STZ-IMT: 46±8,
STZ: 13±5, ANOVA: p<0.01, STZ vs C and vs STZ-IMT: p<0.03]. Histomorphological analysis of pancreatic sections
showed severe decreases in islets number from STZ mice, while a recovery was
observed in islets from STZ-IMT animals, supporting our findings.
IMT504 improves the
diabetic condition in this model of type I diabetes.
Supported by grants from CONICET (PIP 363 2010);
ANPCyT (BID PICT 2006 Nº00200 and BID PICT 2007 Nº 01050) and Universidad de
Buenos Aires (ME 038).
References
1.
Hernando
IA, Montaner AD, Rodriguez JM, Elias F, Flo J, Lopez RA, Zorzopulos J, Hofer
EL, Chasseing NA 2007 IMT504, the prototype of the immunostimulatory
oligonucleotides of the PyNTTTTGT class, increases the number of progenitors of
mesenchymal stem cells both in vitro
and in vivo: potential use in tissue
repair therapy. Stem Cells 25:1047-1054
2. Bianchi MS, Hernando-Insua A, Chasseing NA,
Rodriguez JM, Elias F, Lago N, Zorzopulos J, Libertun C, Montaner A, Lux-Lantos
VA 2010 Oligodeoxynucleotide IMT504 induces a marked recovery of STZ-induced
diabetes in rats: correlation with an early increase in the expression of
nestin and Ngn3 progenitor cell markers. Diabetologia 53:1184-1189
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