Insulin resistance is associated with at least threefold increased risk for prothrombotic state in severely obese youngsters

Biomarkers of insulin sensitivity/resistance

In recent years, remarkable advancements in elucidating the intricate molecular underpinnings of type 2 diabetes mellitus (T2D) have been achieved. Insulin resistance (IR) has been unequivocally acknowledged as the driving pathogenetic mechanism of T2D, preceding disease onset by several years. Nonetheless, diagnostic tools for ascertaining IR are lacking in current clinical practice, representing a critical unmet need; use of the hyperinsulinemic-euglycemic glucose clamp, widely accepted as the gold standard method for evaluating IR at present, is cumbersome in a clinical setting. Thus, the development of well-validated, reliable, and affordable biomarkers of IR has attracted considerable attention from the research community. The biomarkers under investigation can be divided into two major categories: (1) indices or ratios, comprising parameters obtained from a basic or comprehensive metabolic panel and/or derived from anthropometric measurements, and (2) circulating molecules implicated in pathophysiological processes associated with IR. Furthermore, numerous novel biomarkers, including markers of β-cell dysfunction, radiographic quantification of excess visceral adipose tissue, T2D prediction models, certain microRNAs and metabolomic biomarkers, have also provided promising preliminary results. This narrative review aims to present current evidence pertaining to the most notable and exciting biomarkers of IR that are under rigorous evaluation.

Correlation between PAI-1, leptin and ferritin with HOMA in HIV/AIDS patients

BACKGROUND

Data about correlation of interleukins (IL-1 α, IL-1 β, IFN γ, IL-2, IL-4, IL-6, IL-8, IL-10), adipocytokines (leptin, adiponectin, monocyte chemoattractant protein-1 (MCP-1), resistin, plasminogen activator inhibitor-1 (PAI-1), tumor necrosis factor alpha (TNFα), ferritin, C reactive protein (CRP) and vascular endothelial growth factor (VEGF) with homeostasis model assessment (HOMA) in HIV/AIDS patients are still limited. Therefore the aim of this study was to evaluate the possible correlations of serum levels of PAI-1, leptin and ferritin with HOMA in HIV/AIDS patients treated with combined antiretroviral therapy (cART).

METHODS

This cross-sectional study included 64 HIV/AIDS patients, all Caucasians, receiving cART at the HIV/AIDS Centre, Belgrade, Serbia. PAI-1, leptin, ferritin and insulin levels were measured using the Metabolic Syndrome Array I (Randox Laboratories Ltd., London, UK), while adiponectin and resistin levels were measured using Metabolic Syndrome Array II (Randox Laboratories Ltd., London, UK), interleukins (IL-1 α, IL-1 β, IFN γ, IL-2, IL-4, IL-6, IL-8, IL-10), MCP-1, TNF-α as well as VEGF was measured using Cytokine Array I (Randox Laboratories Ltd., London, UK). Insulin resistance was determined using the homeostasis model assessment index (HOMA). Multicollinearity of independent variables in multivariate model was analyzed using Variance Inflation Factor.

RESULTS

Correlation analysis revealed significant correlations between HOMA and waist circumference, body mass index, patients' age, number of cART combinations and triglycerides (p = 0.001, p = 0.001, p = 0.050, p = 0.044, p = 0.002, respectively). HOMA negatively correlated with levels of high density lipoprotein (HDL) (Rho = -0.282; p = 0.025). PAI-1 (Rho = 0.334; p= 0.007) and leptin (Rho = 0.492; p = 0.001) together with ferritin (Rho = 0.396, p = 0.001) positively and significantly correlated with HOMA. Levels of IL-1 α, IL-1 β, IFN γ, IL-2, IL-4, IL-6, IL-8, IL-10, adiponectin, MCP-1, resistin, TNF-α, CRP and VEGF did not significantly correlate with HOMA. Further, multiple logistic regression showed that there is a statistically significant correlation between PAI, leptin and ferritin with HOMA levels (p = 0.042; p < 0.001, p = 0.009).

CONCLUSIONS

We showed significant correlation between PAI-1, leptin and ferritin, independently of each other with HOMA, in HIV/AIDS patients on cART.

Antiplatelets and profibrinolytic activity of Citrullus colocynthis in control and high-fat diet-induced obese rats: mechanisms of action

The current study aimed to investigate the effect of Citrullus colocynthis (C. colocynthis) hydro-alcoholic extract on blood haemostasis in control and high-fat diet (HFD) induced obese rats. In control rats, the extract significantly enhanced bleeding time and plasma levels of tPA and significantly decreased plasma levels PAI-1 and serum levels of thromboxane B2 leading to inhibition of platelets aggregation. In HFD induced obese rats, similar effects were seen and the extract was also able to reverse HFD induced increases in fibrinogen and VWF. Searching for the mechanism, C. colocynthis acts by (1) inhibiting of food intake, (2) inhibiting the activity of pancreatic lipase, (3) decreasing levels of TNF-α and IL-6 and (4) decreasing circulatory levels of the prothrombotic adipokine, leptin and enhanced circulatory levels of the antithrombic adipokines and adiopnectin. In conclusion, C. colocynthis has antiplatelets and profibrinolytic activity in both control and HFD induced obese rats.

Fibrinogen: cardiometabolic risk marker in obese or overweight children and adolescents

OBJECTIVES

To determine the prevalence of increased serum fibrinogen levels and its association with cardiometabolic risk factors in overweight or obese children and adolescents.

METHODS

Cross-sectional study with 138 children and adolescents (overweight or obese) followed at a reference outpatient clinic of the public health care network. Fibrinogen concentration was divided into quartiles, and values above or equal to the third quartile were considered high. The association between high fibrinogen values and cardiometabolic risk factors was assessed using Pearson's chi-squared test or Fisher's exact test, as necessary. Logistic regression was used to adjust variables predictive of fibrinogen levels. Analyses were performed using SPSS version 22.0 and SAS software, considering a confidence interval of 95%.

RESULTS

Serum fibrinogen levels were elevated in 28.3% of individuals, showing association with the presence of high CRP (p=0.003, PR: 2.41, 95% CI: 1.30-4.46) and the presence of four or more risk factors (p=0.042; PR: 1.78, 95% CI: 1.00-3.17). After a logistic regression, only elevated CRP remained associated with altered fibrinogen levels (p=0.024; PR: 1.32; 95% CI: 1.09-5.25).

CONCLUSIONS

Increased fibrinogen was prevalent in the study population and was associated with ultrasensitive C-reactive protein and the presence of four or more cardiovascular risk factors; it should be included in the assessment of individuals at risk.

Are the children and adolescents with congenital heart disease living in Southwestern Ontario really overweight and obese?

OBJECTIVE

To assess the prevalence of overweight and obesity in children with congenital heart disease and compare them with age-matched healthy children in Southwestern Ontario, Canada.

METHODS

We compared the Center of Disease Control weight and body mass index z-scores of 1080 children, aged 2 to 18 years, who presented to our paediatric cardiology outpatient clinic from 2008 to 2010 for congenital heart disease with 1083 healthy controls.

RESULTS

In all, 18.2% of the children with congenital heart disease and 20.8% of healthy children were identified to be either overweight or obese. Overall, the weight category distribution had been similar between the congenital heart disease and healthy control groups, as well as between the congenital heart disease subgroups. There was no difference in normal weight and overweight/obese categories between children with congenital heart disease and healthy children. The underweight category, however, showed a significantly higher prevalence in congenital heart disease compared with healthy children (6.8 and 4.5%, respectively, p = 0.03).

CONCLUSION

The prevalence of overweight/obesity did not differ in children with congenital heart disease compared with age-matched healthy children; however, it is still high (18.2%). Obesity may represent an additional risk factor for the long-term cardiovascular health of congenital heart disease patients aside from the underlying heart defect.

Suboptimal glycaemic control enhances the risk of impaired prothrombotic state in youths with type 1 diabetes mellitus

OBJECTIVE

To estimate markers of prothrombotic state and endothelial dysfunction in youths with type 1 diabetes mellitus (T1DM) and investigate possible associations with anthropometric/demographic data, glycaemic control and lipid profile.

METHODS

In a cross-sectional design, we recruited 155 youths with T1DM and determined levels of plasminogen activator inhibitor-1-antigen (PAI-1-Ag), von Willebrand factor-antigen (vWF-Ag), fibrinogen (FB), lipids and glycosylated haemoglobin (HbA1c).

RESULTS

Of all the participants, 76 (49%) had increased levels of at least one of prothrombotic factors. Suboptimal glycaemic control was associated with a worse lipid profile and an eightfold increased risk of elevated vWF-Ag levels. Higher vWF-Ag concentrations were also correlated with impaired lipid profile and increased HbA1c values, whereas PAI-1-Ag was positively correlated only with triglyceride levels. After adjustment for potential confounders, only HbA1c contributed independently to the variation in vWF-Ag levels.

CONCLUSION

Impaired prothrombotic state and consequently endothelial dysfunction are present in youths with T1DM, representing a cumulative risk factor for future cardiovascular disease (CVD). Achievement and maintenance of euglycaemia and normolipidaemia are crucial to decelerate progress of this process.

A matter of fat: insulin resistance and oxidative stress

BACKGROUND

Obesity is linked to insulin resistance (IR), which can lead to type 2 diabetes mellitus. Oxidative stress present in early obesity may favor the progression to comorbid conditions.

OBJECTIVE

To examine the relationship between oxidative stress biomarkers and the severity of IR in a group of obese children.

METHODS

Forty obese children with a body mass index (BMI) Z-score ≥ 2 were divided into two groups using the median obtained for the homeostasis model assessment of IR (HOMA-IR). Anthropometric parameters (including body fat composition by bioelectrical impedance) and biochemical parameters were assessed. The following biomarkers of oxidative stress were measured: malondialdehyde (MDA), carbonyl groups (CG), reduced glutathione, oxidized low-density lipoprotein, and vitamin E. Comparisons were adjusted for gender and Tanner stage.

RESULTS

Children with high values of HOMA-IR were more likely to have high body fat percentage and waist circumferences. However, the BMI Z-score did not correlate to the level of IR. Children with higher values of HOMA-IR presented increased levels of markers of oxidative stress in lipids (MDA, p = 0.005) and proteins (CG, p = 0.015). Moreover, MDA increased with increasing levels of HOMA-IR (r = 0.50, p = 0.002), suggesting that lipoperoxidation increases as IR worsens. In a multivariate regression model, only HOMA-IR was predictive of MDA values, irrespective of adiposity parameters and other metabolic risk factors (r2 = 0.22, p = 0.002).

CONCLUSIONS

Oxidative stress increases in obese children according to the severity of IR, which could be linked to the development of comorbidities.

Clinical practice: the effect of obesity in children with congenital heart disease

Childhood obesity has reached epidemic proportions in many parts of the world. This epidemic has also affected children and adults with congenital heart disease (CHD). Over one quarter of children with CHD are overweight or obese. Important comorbidities are associated with obesity including type 2 diabetes, systemic hypertension, hyperlipidemia, and obstructive sleep apnea. Obese children with CHD often have the traditional risk factors such as genetic predisposition, sedentary lifestyle, and poor dietary habits. However, they may also have unique risk factors such as higher caloric needs in early infancy and exercise restriction in childhood. Similar to children with normal hearts, those with CHD have higher left ventricular mass and abnormal vascular function and are more likely to have systemic hypertension. In the long term, these comorbidities may have a more profound effect on children who have underlying functional and/or anatomical abnormalities of the heart. As more children with CHD are now surviving into adulthood, investigating therapeutic interventions to treat and prevent obesity in this population is of utmost importance. Recommendations for safe physical activity, recreation sport, and exercise training for children with CHD have recently been published. These guidelines may help health care providers to change their practice of exercise restriction.

Insulin resistance and risk of venous thromboembolism: results of a population-based cohort study

BACKGROUND

Obesity is an established risk factor for venous thromboembolism (VTE), but it is uncertain how this is mediated. Insulin resistance has a central role in the pathophysiology of the metabolic effects of obesity.

OBJECTIVE

We aimed to investigate whether insulin resistance is a risk factor for VTE.

METHODS

For this analysis we used the PREVEND prospective community-based observational cohort study. Insulin resistance was measured as HOMA-IR (homeostasis model assessment of insulin resistance) and fasting insulin. VTE was assessed using databases of the national registries of hospital discharge diagnoses, death certificates and the regional anticoagulation clinic.

RESULTS

Out of 7393 subjects, 114 developed VTE during a median follow-up of 10.5 years. High HOMA-IR was associated with increased risk of VTE after adjustment for traditional cardiovascular risk factors, CRP and markers of endothelial dysfunction (hazard ratio [HR], 1.38; 95% confidence interval [95% CI], 1.09-1.75; P=0.007). When body mass index (BMI) was added to the model, BMI was a strong risk predictor for VTE (HR, 1.53; 95% CI, 1.24-1.88; P<0.001) whereas HOMA-IR no longer showed such an association (HR, 1.11; 95% CI, 0.85-1.43; P=0.45). Results were similar for fasting insulin.

CONCLUSION

Our population-based cohort study shows an increased risk of VTE in subjects with increasing insulin resistance but not independently of BMI.

Association of plasminogen activator inhibitor-1 and tissue plasminogen activator with type 2 diabetes and metabolic syndrome in Malaysian subjects

Background

Increased plasma plasminogen activator inhibitor-1 (PAI-1) activity and decreased tissue plasminogen activator (tPA) activity could be considered a true component of the metabolic syndrome (MetS) associated with an increased risk of developing cardiovascular diseases (CVD) and fibrinolytic abnormalities. The aim of this study was to investigate the association of tPA and its inhibitor PAI-1 with type 2 diabetes (T2D) and MetS and interrelationship between PAI-1and tPA activities and antigens in Malaysian T2D and normal subjects.

Methods

The plasma activities and antigens of PAI-1 and tPA and the levels of the tPA/PAI-1 complex as well as serum insulin, parameter of the coronary risk panel and plasma glucose at fasting state were studied in 303 T2D subjects (227 with MetS and 76 without MetS), 131 normal non-diabetic non-metabolic subjects and 101 non-diabetic MetS subjects.

Results

The PAI-1 activity was higher in subjects with T2D with MetS (P = 9.8 × 10^-19) and non-diabetic subjects with MetS (P = 3.0 × 10^-15), whereas the tPA activity was lower in T2D with MetS (P = 0.003) as compare to normal subjects. Plasma tPA antigen levels were higher in subjects with T2D with MetS (P = 8.9 × 10^-24), T2D without MetS (P = 1.3 × 10^-13) and non-diabetic MetS subjects (P = 0.002). The activity and antigen of PAI-1 in normal subjects were related to insulin resistance (P = 2.2 × 10^-4; 0.007). Additionally, the PAI-1 activity was associated with an increased waist circumference (P = 2.2 × 10^-4) and decreased HDL-c (P = 0.005), whereas the tPA activity was associated with decreased FBG (P = 0.028). The highest correlation was between PAI-1 activity and its antigen (R² = 0.695, P = 1.1 × 10^-36) in diabetic subjects. The tPA activity negatively correlated with its antigen (R² = -0.444, P = 7.7 × 10^-13) in normal subjects and with the PAI-1 activity and antigen (R² = -0.319, P = 9.9 × 10^-12; R2 = -0.228, P = 3.4 × 10^-6) in diabetic subjects.

Conclusions

PAI-1 and tPA activities and antigens were associated with diabetes and MetS parameters in Malaysian subjects.