The effects of Lactobacillus casei on glycemic response, serum sirtuin1 and fetuin-A levels in patients with type 2 diabetes: A controlled clinical trial

Abstract

Background and Objectives: Type 2 diabetes mellitus (T2DM) is a metabolic disorder that is known by high blood glucose and altered macronutrients’ metabolism. T2DM is related to the intestinal microbiota with numerous molecular mechanisms. Modulation of the intestinal microbiota by probiotics may be effective in management of T2DM by several mechanisms. The objective of present trial was to evaluate the effect of L. casei on glycemic control and serum sirtuin1 (SITR1) and fetuin-A in patients with T2DM. Method: Forty patients with T2DM (n=20 for each group) were assigned into two groups in this randomized, double-blind, placebo-controlled clinical trial. Volunteers were composed of patients with T2DM, 30-50 years of age, and body mass index (BMI) lower than 35 kg/m2. All patients had been diagnosed with T2DM for at least one year. Exclusion criteria were smoking, the presence of kidney, liver, and/or inflammatory intestinal disease, thyroid disorders, immunodeficiency diseases, required insulin injections, use of nutritional supplements within the previous three weeks of testing, use of estrogen or progesterone, pregnancy or breastfeeding, consuming any type of antibiotics, and consuming any other probiotic products within the previous two months of testing. The patients in the probiotic group received a daily capsule that contained a minimum of 108 colony-forming units of Lactobacillus casei for 8 week. The placebo group took capsules filled with maltodextrin for the same time period. Dietary intake questionnaires, anthropometric measurements, and fasting blood samples were collected, and the participants were assessed by an endocrinologist at baseline and at the end of the trial. Statistical analysis was performed by SPSS software (ver. 17) and in all analyses, p values less than 0.05 were considered statistically as significant. Results: After 8 week of L. casei supplementation, fasting blood sugar, insulin concentration, and insulin resistance were significantly decreased in intervention group (p=0.002, p=0.035, p=0.001; respectively). Moreover; HbA1C was reduced after intervention in probiotic group (p=0.190). The intervention significantly increased SITR1 level and decreased fetuin-A level in probiotic group (p=0.006, p =0.008; respectively). The between group differences of fasting blood sugar, insulin concentration, and insulin resistance (p=0.013, p=0.028, p=0.007; respectively) and serum level of SITR1 and fetuin-A were significant (p=0.040, p =0.023; respectively). Conclusions: L. casei supplementation could improve biochemical parameters in patients with T2DM. Considering the finding of present trial and by doing more research in this field, the mentioned bacterial strain could be a therapeutic supplement for diabetic subjects. Affecting the SIRT1 and fetuin-A expression introduces a new known mechanism of probiotic action in diabetes management.