Systemic F2-Isoprostane Levels in Predisposition to Obesity and Type 2 Diabetes: Emphasis on Racial Differences

Association between F2-Isoprostane Metabolites and Weight Change in Older Women: A Longitudinal Analysis

INTRODUCTION

Theoretically, some metabolic traits may predispose older individuals to weight loss during aging, leading to increased all-cause mortality and many serious health issues. Biomarkers to robustly predict progressive weight loss during aging are, however, lacking. We prospectively assessed if urinary levels of F2-isoprostanes and their peroxisomal β-oxidation metabolite, 2,3-dinor-5,6-dihydro-15-F2t-isoprostane (F2-IsoP-M), were associated with subsequent weight loss in middle-aged and older women.

METHODS

Included in the analysis were 2,066 women aged 40-70 years, a subset of a prospective cohort study. F2-isoprostanes (F2-IsoPs) and its β-oxidation metabolite, F2-IsoP-M, were measured in urine using gas chromatography-mass spectrometry. Measurements of anthropometry and exposures to major determinants of body weight were performed at baseline and repeated thrice over 15-year follow-up. The longitudinal associations of F2-IsoP-M and the F2-IsoP-M to its parent compound, F2-IsoP, ratio (MPR) with repeatedly measured weight changes were examined using linear mixed-effect models.

RESULTS

After adjusting for time-varying covariates: energy intake, physical activity, and comorbidity index, among others, levels of F2-IsoP-M and the MPR were both inversely associated with percentage of weight change. Weight in the highest quartile of these two biomarkers was 1.33% (95% CI = -2.41, -0.24) and 1.09% (95% CI = -2.16, -0.02) lower than those in the lowest quartile group, with p for trend of 0.01 and 0.03, respectively. The inverse association was consistently seen across follow-up periods, although appearing stronger with prolonged follow-up. There was no association between the parent compound, F2-IsoPs, and weight change.

CONCLUSION

This study demonstrates the first piece of evidence to associate F2-IsoP metabolism, peroxisomal β-oxidation, with weight loss in older women. Further investigations into the role of lipid peroxidation and peroxisomal β-oxidation in weight change among older individuals are warranted.

Inflammation, oxidative stress and mitochondrial dysfunction in the progression of type II diabetes mellitus with coexisting hypertension

Introduction

Type II diabetes mellitus (T2DM) is a metabolic disorder that poses a serious health concern worldwide due to its rising prevalence. Hypertension (HT) is a frequent comorbidity of T2DM, with the co-occurrence of both conditions increasing the risk of diabetes-associated complications. Inflammation and oxidative stress (OS) have been identified as leading factors in the development and progression of both T2DM and HT. However, OS and inflammation processes associated with these two comorbidities are not fully understood. This study aimed to explore changes in the levels of plasma and urinary inflammatory and OS biomarkers, along with mitochondrial OS biomarkers connected to mitochondrial dysfunction (MitD). These markers may provide a more comprehensive perspective associated with disease progression from no diabetes, and prediabetes, to T2DM coexisting with HT in a cohort of patients attending a diabetes health clinic in Australia.

Methods

Three-hundred and eighty-four participants were divided into four groups according to disease status: 210 healthy controls, 55 prediabetic patients, 32 T2DM, and 87 patients with T2DM and HT (T2DM+HT). Kruskal-Wallis and χ2 tests were conducted between the four groups to detect significant differences for numerical and categorical variables, respectively.

Results and discussion

For the transition from prediabetes to T2DM, interleukin-10 (IL-10), C-reactive protein (CRP), 8-hydroxy-2'-deoxyguanosine (8-OHdG), humanin (HN), and p66^Shc were the most discriminatory biomarkers, generally displaying elevated levels of inflammation and OS in T2DM, in addition to disrupted mitochondrial function as revealed by p66^Shc and HN. Disease progression from T2DM to T2DM+HT indicated lower levels of inflammation and OS as revealed through IL-10, interleukin-6 (IL-6), interleukin-1β (IL-1β), 8-OHdG and oxidized glutathione (GSSG) levels, most likely due to antihypertensive medication use in the T2DM +HT patient group. The results also indicated better mitochondrial function in this group as shown through higher HN and lower p66^Shc levels, which can also be attributed to medication use. However, monocyte chemoattractant protein-1 (MCP-1) levels appeared to be independent of medication, providing an effective biomarker even in the presence of medication use. The results of this study suggest that a more comprehensive review of inflammation and OS biomarkers is more effective in discriminating between the stages of T2DM progression in the presence or absence of HT. Our results further indicate the usefulness of medication use, especially with respect to the known involvement of inflammation and OS in disease progression, highlighting specific biomarkers during disease progression and therefore allowing a more targeted individualized treatment plan.

The association between prenatal F2-isoprostanes and child wheeze/asthma and modification by maternal race

BACKGROUND

Childhood wheeze, asthma, and allergic rhinitis are common and likely have prenatal origins. Oxidative stress is associated with respiratory disease, but the association of oxidative stress during the prenatal period with development of respiratory and atopic disease in childhood, particularly beyond the infancy period, is unknown. This study aims to investigate associations between prenatal oxidative stress, measured by maternal urinary F2-isoprostanes, and child respiratory outcomes, including effect modification by maternal race.

METHODS

We prospectively studied Black (n = 717) and White (n = 363) mother-child dyads. We measured F2-isoprostanes in 2nd-trimester urine (ng/mg-creatinine). At approximately age 4, we obtained parent report of provider-diagnosed asthma (ever), current wheeze, current asthma (diagnosis, symptoms and/or medication), and current allergic rhinitis (current defined as previous 12 months). We used multivariable logistic regression to estimate adjusted odds ratios (aOR) and 95% confidence intervals (95%CI) per interquartile range (IQR) increase in F2-isoprostane concentration, controlling for confounders. We examined modification by maternal race using interaction terms.

RESULTS

The prevalence of provider-diagnosed asthma and current wheeze, asthma and allergic rhinitis was 14%, 19%, 15%, and 24%, respectively. Median (IQR) F2-isoprostane levels were 2.1 (1.6, 2.9) ng/mg-creatinine. Associations between prenatal F2-isoprostanes and provider-diagnosed asthma, current wheeze, and current asthma were modified by maternal race. Results were strongest for current wheeze (aOR [95%CI]: 1.55 [1.16, 2.06] for White; 0.98 [0.78, 1.22] for Black; p-interaction = 0.01). We observed no association between F2-isoprostanes and allergic rhinitis.

CONCLUSION

Prenatal urinary F2-isoprostanes may be a marker associated with childhood wheeze/asthma in certain populations. Research is needed to understand underlying mechanisms and racial differences.

Oxidative stress and obesity

Obesity is a disease of excessive accumulation of adipose tissue due to an increased energy intake which is disproportionate to the energy expenditure in the body. The visceral adipose tissue in the obese accumulated in that way increases the risk of developing a number of metabolic and cardiovascular diseases. Disorders such as diabetes, dyslipidemia, inflammation, endothelial dysfunction and mitochondria can contribute to the development of oxidative stress, which is especially pronounced in the abdominal type of obesity. Obesity can induce systemic oxidative stress through a variety of biochemical mechanisms. Although ROS is generated in a large number of cells, mitochondria play a significant role in their intracellular production through the process of oxidative phosphorylation of the respiratory chain, and in fatty acid oxidation reactions. Oxidative stress is a unique link between the various molecular disorders present in the development of insulin resistance that plays a key role in the pathogenesis and progression of chronic metabolic, proinflammatory diseases. The progression of insulin resistance is also affected by inflammation. Both of these can be the cause and the consequence of obesity. The synthesis of the inflammatory mediators is induced by oxidative stress, thus bringing the inflammation and the oxidative stress into a very significant relation. This review aims to highlight recent findings on the role of oxidative stress in the pathogenesis of obesity, with special reference to the mechanisms that explain its occurrence.