Safety and effects of acetylated and butyrylated high amylose maize starch in recently diagnosed youths with type 1 diabetes; a Pilot Study

Abstract

Acetylated and butyrylated high amylose starch (HAMS-AB) is a prebiotic shown to be effective in type 1 diabetes (T1D) prevention in mouse models and is safe in adults with established T1D. HAMS-AB alters the gut microbiome profile with increased bacterial fermenters that produce short chain fatty acids (SCFAs) with anti-inflammatory and immune-modulatory effects. We performed a pilot study using a cross-over design to assess the safety and efficacy of 4 weeks of oral HAMS-AB consumption by recently diagnosed (< 2 years of diagnosis) youths with T1D. Seven individuals completed the study. The mean±SD age was 15.0±1.2 years, diabetes duration 19.5±6.3 months, 5/7 were female and 4/7 were White, all with a BMI of < 85^th%. The prebiotic was safe. Following prebiotic intake, gut microbiome changes were seen, including a notable increase in the relative abundance of fermenters such as Bifidobacterium and Faecalibacterium. Treatment was also associated with changes in bacterial functional pathways associated with either improved energy metabolism (upregulation of tyrosine metabolism) or anti-inflammatory effects (reduced geraniol degradation). There were no differences in stool SCFA levels. Plasma metabolites associated with improved glycemia, such as hippurate, were significantly increased after treatment and there were positive and significant changes in the immune regulatory function of mucosal associated invariant T cells. There was a significant decrease in the area under the curve glucose but not C-peptide, as measured during a mixed meal tolerance testing, following the prebiotic consumption. In summary, the prebiotic HAMS-AB was safe in adolescents with T1D and showed promising effects on the gut microbiome composition, function and immune regulatory function.

Keywords: Beta cell function; C-peptide levels; HAMS-AB; SCFAs; dietary intervention; glucose regulation; glycemic control; metabolomics; mixed meal tolerance test (MMTT); type 1 diabetes (T1D).

Figure 1:. Changes in relative abundance of different species in relation to the intervention type (HAMS-AB vs Diabetic Diet)

Figure 2:. Modulation of the immune response by HAMS-AB. PBMCs were harvested from patients' blood and activated by MAIT cell antigen 5-OP-RU (A &B) or PMA/Ionomycin (C-E) overnight. MAIT cell phenotypes were analyzed by flow cytometry. Data were analyzed comparing pre- and post- diabetic (upper panels) and prebiotic (lower panels) diets. *, P<0.05, Wilcoxon paired test.