A Short-TERM Treatment with Oligonucleotide IMT504 Inhibits Insulitis and Lowers Blood Glucose in Female NON-Obese Diabetic (NOD/Ltj) MICE  

Presentation Number: LB MON 80
Date of Presentation: April 3rd, 2017

Stefania Bianchi*1, Milena Massimino2, Carlos Libertun3, Victoria A Lux-Lantos3 and Maria Silvia Bianchi2
1IBYME, Buenos Aires, ARGENTINA, 2IBYME-CONICET, Buenos Aires, Argentina, 3Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina

Abstract

We have shown that a long term-treatment with the immunomodulatory oligonucleotide IMT504 (20mg/kg/day) induced a marked recovery of glycemia (screened weekly), glucose clearence (by glucose tolerance test), insulin secretion (by area under the curve in insulin secretion test), and beta cell function (by HOMA beta cell index) on a spontaneous autoimmune diabetes model (in male and female NOD/Ltj mice).

Considering previous results, we decided to analyze the minimun dose at which the IMT504 has an effect on glycemic control and insulitis with a short-term treatment. Female NOD/LtJ mice were screened weekly starting on week 10 by measuring glycemia (Gly) in fed conditions at noon. Animals were considered diabetic after two consecutive Gly levels ≥ 250 mg/dl. Thereafter, mice were treated with one daily dose of IMT504 for five days (IMT: 20mg/kg/day, 6mg/kg/day or 2mg/kg/day) or saline as diabetic control (DC). All mice were sacrificed the day following the last injection (day 6 after diabetes onset); after 3 hours fast, blood glucose was measured, animals were sacrificed by decapitation, blood samples were collected and pancreases were dissected for histological studies: hematoxylin-eosin staining for insulitis analysis, and insulin-glucagon staining for morphometric analysis.

We observed that 12.5% (1/8) DC mice showed spontaneous reversion of the diabetic condition (normal blood glucose) whereas IMT treatment induced a marked improvement in blood glucose in 62.5% (5/8), 50% (4/8) and 75% (6/8) of mice with 2mg/kg/day, 6mg/kg/day, and 20mg/kg/day, respectively (X2: DC vs IMT20: p<0.025).

Gly did not vary with time (day 6 vs day 1) in DC mice while it significantly diminished with IMT treatment [Gly (mg/dl): repeated measure ANOVA: interaction, p<0.001, DC: Day 1: 330.1 ± 71.4 vs Day 6: 333.0 ± 117.5, IMT2: Day 1: 303.2 ± 49.3 vs Day 6: 232.6 ± 56.6, IMT6: Day 1: 282.8 ± 22.4 vs Day 6: 194.0 ± 43.9, IMT20: Day 1: 313.2 ± 42.3 vs Day 6: 146.7 ± 41.6, IMT20: Day 1 vs Day 6: p<0.02]. Body weights did not differ among groups (repeated measure ANOVA: NS). Fasted glycemia (day 6) also diminshed significantly with IMT20 treatment (One way ANOVA: p<0.03, DC vs IMT20: p<0.04). As IMT20 was the most successful in glycemic control, we analyzed insulitis in this group in comparison to diabetic controls. IMT20 showed a marked reduction in leukocyte islet infiltration after this short treatment, measured by insulitis index (DC: 0.66 ± 0.05 vs IMT20: 0.48 ± 0.05, Student’s t test: p<0.05).

Taken together, these results demonstrate that IMT504 treatment promotes an early, significant improvement in the diabetic condition in NOD/Ltj mice warranting further investigation of its mechanism of action.

Nothing to Disclose: SB,MM,CL,VLL,MSB

Sources of Research Support: CONICET- PIP 571 and ANPCYT- PICT 707 (VLL); ANPCYT- PICT 0061 and UBA- ME043 (CL). René Barón Foundation and Williams Foundation.

 

Nothing to Disclose: SB, MM, CL, VAL, MSB