High day-to-day and diurnal variability of oxidative stress and inflammation biomarkers in people with type 2 diabetes mellitus and healthy individuals

Abstract

Objective:: Assess the variability and differences in oxidative stress, antioxidant, and inflammatory biomarkers in people with type 2 diabetes mellitus (T2D) and healthy controls. Methods:: Ten men and women diagnosed with T2D and ten healthy matched controls (CON) were recruited. Participants had venous blood taken at six different time points on different days, three in the morning (after overnight fast) and three in the afternoon. Inflammation (IL-6, 8, 10 and TNF-α), oxidative stress/antioxidant biomarkers (F 2-isoprostanes, protein carbonyls, total antioxidant capacity (TAC), glutathione peroxidase activity, IL-6, 8 & 10 and TNF-α) were assessed. Results:: Biomarker concentrations were similar between groups. There was large variability in nearly all biomarkers for both groups. For inflammatory measures, intra-individual coefficients of variation (CV) ranged from 64.0-92.1% and 100.9-259.0% for inter-individual differences. CVs for oxidative stress markers were lower (7.4-31.2% for intra-individual and 8.6-43.0% for inter-individual). TAC had the lowest intra-individual CV-7% for T2D and 8% for CON. Protein carbonyls were more variable in the afternoon (34% CV) compared to morning (24% CV) in CON. IL-6 intra-individual CV was different between groups for afternoon measurements (93% T2D, 60% CON). Conclusion:: Oxidative stress and inflammatory biomarkers show considerable variation in both T2D and healthy populations.

Intra-Individual Variation and Reliability of Biomarkers of the Antioxidant Defense System by Considering Dietary and Lifestyle Factors in Premenopausal Women

“…In a previous study, which reported the intra-/inter-individual variation of 20 apparently healthy subjects based on eight consecutive days, glutathione expressed as µmol/g Hb showed an intra-/inter-individual variation of around 14% and 11%, respectively [69], which is comparable to our results with regard to CV T (10-16%) and slightly higher with regard to CV G (5-9%). In a recent study analyzing the intraand inter-individual variation and ICC for the total antioxidant capacity, based on two afternoon and three morning collections over two weeks in ten healthy subjects, a very low ICC of 0.01 and an intra-individual variation of 8% was reported [66], similar to our observations. In addition, the total antioxidant capacity was the parameter with the lowest inter-individual variation, albeit inter-individual variation was higher (8%) than in the present study [66].…”

“…In a recent study analyzing the intraand inter-individual variation and ICC for the total antioxidant capacity, based on two afternoon and three morning collections over two weeks in ten healthy subjects, a very low ICC of 0.01 and an intra-individual variation of 8% was reported [66], similar to our observations. In addition, the total antioxidant capacity was the parameter with the lowest inter-individual variation, albeit inter-individual variation was higher (8%) than in the present study [66]. Because of the differences in study designs and populations, the results are not directly comparable.…”

“…The reported ICC values in the literature varied greatly. For example, in studies which did not focus on circadian effects or changes within menstrual cycle, the following ICC values were reported: bilirubin 0.4–0.8 [ 21 ], uric acid 0.7–1.0 [ 21 ], vitamin C 0.4–0.8 [ 20 , 23 ], α- and/or γ-tocopherol 0.1–0.9 [ 19 , 23 , 26 ], retinol 0.4–0.9 [ 19 , 20 , 26 ], carotenoids 0.2–0.8 [ 19 , 20 , 23 ], total antioxidant capacity (equivalent to TEAC) 0.01 [ 66 ] and reduced/oxidized glutathione 0.6 [ 25 ]. Overall, the ICC values of the present study are in the range of previously reported ICC values, with the exception of glutathione.…”

Amelioration of Endothelial Dysfunction in Diabetes: Role of Takeda G Protein–Coupled Receptor 5

“…Both oxidative stress and inflammation interfere with insulin signaling ( Wen and Duffy, 2017 ), leading to insulin resistance, DM, and related complications ( Baig et al, 2020 ), and these processes are considered to be important components of the pathogenesis of DM. Persistent oxidative stress and the destruction of normal cellular redox homeostasis typically occur alongside chronic inflammation and the two are highly interrelated; therefore, we will discuss their impact on ECs in diabetes together ( Mallard et al, 2020 ). Vascular ECs are a key site of metabolic dysregulation in diabetes ( Khan and Chakrabarti, 2006 ).…”

Measuring and interpreting pervasive heterogeneity, poikilosis

“…Inter‐individual variation is wide for many biomarkers and many times close to population variation, such as in the analysis of 21 hematological parameters 37 . In addition to cohort/population variation there are day‐to‐day and within‐day variations, which can be large, exemplified by circulating cell‐free DNA levels 38 and inflammation biomarkers in type 2 diabetes patients and healthy controls, 39 respectively.…”