This study will help us understand the possible beneficial effects of insulin in inflammation. Inflamamtion is considered to be the cause of atherosclerosis and heart disease.
Obesity and type 2 diabetes are major health problems in the United States and the world. Both conditions are characterized by increased inflammation and oxidative stress and are associated with increased risk of cardiovascular disease. Our previous work shows that insulin exerts a prompt and powerful anti-inflammatory effect, on circulating blood cells and in plasma in healthy subjects and in critically ill patients. Toll like receptors (TLRs) recognize bacterial and viral products like endotoxin and viruses and are major determinants of the inflammatory response against foreign pathogens. In view of the recent data showing that TLRs recognize a range of molecules and proteins that are not of pathogenic source like saturated lipids and that TLRs are involved in the pathogenesis of atherosclerosis which leads to cardiovascular disease and insulin resistance which leads to type 2 diabetes (DM) we hypothesized that insulin infusion suppresses TLRs expression. Our preliminary data show that insulin infusion for 4 hours reduces the levels of many TLRs and thus might protect from inflammation induced conditions We therefore propose to investigate, in more detail, the effect of infusing different doses of insulin on TLRs mRNA and protein levels and its activity in obese and DM subjects over a longer infusion period and a larger number of subjects in circulating white blood cells and in fat tissue. Also we will be comparing the baseline levels of TLRs and TLRs related proteins as well as their modulation by insulin between normal, obese and DM subjects.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
42
insulin to be infused at 3.5 units/hour along with Dextrose 12.5% at a rate to achieve blood glucose levels between 80-120mg/dl
Dextrose 12.5% will be infused at a rate to maintain blood glucose level 80-120mg/dl
Saline will be infused at 100ml/hr
Millard Fillmore Gates Hospital
Buffalo, New York, United States
Suppression of Toll Like Receptor (TLR) 2 mRNA by Insulin
percent change from baseline (0hrs) in TLR2 mRNA in mononuclear cells (MNC) following up to 24 hrs of 3.5U/hr insulin infusion (II) adjusted to the similar average change following up to 24hr infusion of dextrose (DI) and saline (SI) control groups. The correction is calculated as follows: Corrected percent change from baseline following II= change from baseline following II - (average change from baseline following DI and SI)\*100. Changes from baseline are calculated as: (expression at 24hrs-expression at 0hr)/expression at 0hr.
Time frame: 24 hours
Change in TLR4 mRNA in MNC
percent change from baseline (0hrs) in TLR4 mRNA in mononuclear cells (MNC) following up to 24 hrs of 3.5U/hr insulin infusion (II) adjusted to the same change following up to 24hr infusion of dextrose (DI) and saline (SI) control groups in this order. The correction is conducted as follows: Corrected percent change from baseline following II= change from baseline following II - (average change from baseline following DI and SI)\*100. Changes from baseline are calculated as: (expression at 24hrs-expression at 0hr)/expression at 0hr. 2- For each PCR measurement of specific target gene, relative expression of 3 housekeeping genes (beta-actin, ubiquitin C and cyclophilin A) from the same cDNA is assessed, and normalization factor (based on the 3 genes) is calculated and entered into PCR software to automatically adjust/normalize target gene expression
Time frame: 24 hours
Change in CD14 Expression in MNC
percent change from baseline (0hrs) in CD14 mRNA in mononuclear cells (MNC) following up to 24 hrs of 3.5U/hr insulin infusion (II) adjusted to the similar average change following up to 24hr infusion of dextrose (DI) and saline (SI) control groups in this specific order. The correction is conducted as follows: Corrected percent change from baseline following II= change from baseline following II - (average change from baseline following DI and SI)\*100. Changes from baseline are calculated as: (expression at 24hrs-expression at 0hr)/expression at 0hr. For each PCR measurement of specific target gene, relative expression of 3 housekeeping genes (beta-actin, ubiquitin C and cyclophilin A) from the same cDNA is assessed, and normalization factor (based on the 3 genes) is calculated and entered into PCR software to automatically adjust/normalize target gene expression.
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Time frame: 24hrs
Fasting TLR2 mRNA Expression Levels in the 3 Cohorts
Comparison of TLR2 mRNA expression in MNC in fasting condition. Fasting TLR2 mRNA expression is measured using real-time PCR at baselines of the 3 visits (II, DI, SI visits) is averaged and reported as arbitrary units. For each PCR measurement of specific target gene, relative expression of 3 housekeeping genes (beta-actin, ubiquitin C and cyclophilin A) from the same cDNA is assessed, and normalization factor (based on the 3 genes) is calculated and entered into PCR software to automatically adjust/normalize target gene expression.
Time frame: baseline/fasting