ADIPOQ and adiponectin: the common ground of hyperglycemia and coronary artery disease?

ADIPOQ-rs2241766 polymorphism is associated with changes in cholesterol levels of Mexican adolescents

BACKGROUND

The ADIPOQ gene encodes a fat-derived protein hormone with a preponderant role in the homeostasis of glucose and fatty acids. However, previous association studies between ADIPOQ genetic variants and metabolic disorders have shown controversial results. In this study, we evaluated the effect of the ADIPOQ-rs2241766 polymorphism on diverse biochemical parameters (i.e., insulin resistance, atherogenic index, overweight and obesity) in an adolescent population from Mexico.

METHODS

A cross-sectional study with convenience sampling was carried out in 356 adolescents from Northern Mexico. They were classified by sex and BMI-z score. The biochemical parameters were measured from blood samples using conventional methods. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

RESULTS

In low and normal weight groups, GG carriers had a significantly higher cholesterol level (P ≤ 0.05) than TG and TT carriers. However, there was no association between ADIPOQ-rs2241766 polymorphism and atherogenic index, overweight, or obesity.

CONCLUSIONS

Our findings suggest that the cholesterol levels are under the influence of the ADIPOQ-rs2241766 polymorphism in Mexican adolescents and may explain how ADIPOQ variants increase the risk of developing metabolic disorders. Nevertheless, further studies are required to rule out the influence of other genetic and non-genetic factors.

Genes associated with Type 2 Diabetes and vascular complications

Type 2 Diabetes (T2D) is a chronic disease associated with a number of micro- and macrovascular complications that increase the morbidity and mortality of patients. The risk of diabetic complications has a strong genetic component. To this end, we sought to evaluate the association of 40 single nucleotide polymorphisms (SNPs) in 21 candidate genes with T2D and its vascular complications in 503 T2D patients and 580 healthy controls. The genes were chosen because previously reported to be associated with T2D complications and/or with the aging process. We replicated the association of T2D risk with IGF2BP rs4402960 and detected novel associations with TERT rs2735940 and rs2736098. The addition of these SNPs to a model including traditional risk factors slightly improved risk prediction. After stratification of patients according to the presence/absence of vascular complications, we found significant associations of variants in the CAT, FTO, and UCP1 genes with diabetic retinopathy and nephropathy. Additionally, a variant in the ADIPOQ gene was found associated with macrovascular complications. Notably, these genes are involved in some way in mitochondrial biology and reactive oxygen species regulation. Hence, our findings strongly suggest a potential link between mitochondrial oxidative homeostasis and individual predisposition to diabetic vascular complications.

The mechanism by which moderate alcohol consumption influences coronary heart disease

Background

Moderate alcohol consumption is associated with a lower risk for coronary heart disease (CHD). A suitably integrated view of the CHD pathogenesis pathway will help to elucidate how moderate alcohol consumption could reduce CHD risk.

Methods

A comprehensive literature review was conducted focusing on the pathogenesis of CHD. Biomarker data were further systematically analysed from 294 cohort studies, comprising 1 161 560 subjects. From the above a suitably integrated CHD pathogenetic system for the purpose of this study was developed.

Results

The resulting integrated system now provides insight into the integrated higher-order interactions underlying CHD and moderate alcohol consumption. A novel ‘connection graph’ further simplifies these interactions by illustrating the relationship between moderate alcohol consumption and the relative risks (RR) attributed to various measureable CHD serological biomarkers. Thus, the possible reasons for the reduced RR for CHD with moderate alcohol consumption become clear at a glance.

Conclusions

An integrated high-level model of CHD, its pathogenesis, biomarkers, and moderate alcohol consumption provides a summary of the evidence that a causal relationship between CHD risk and moderate alcohol consumption may exist. It also shows the importance of each CHD pathway that moderate alcohol consumption influences.

How do high glycemic load diets influence coronary heart disease?

Background

Diet has a significant relationship with the risk of coronary heart disease (CHD). Traditionally the effect of diet on CHD was measured with the biomarker for low-density lipoprotein (LDL) cholesterol. However, LDL is not the only or even the most important biomarker for CHD risk. A suitably integrated view of the mechanism by which diet influences the detailed CHD pathogenetic pathways is therefore needed in order to better understand CHD risk factors and help with better holistic CHD prevention and treatment decisions.

Methods

A systematic review of the existing literature was conducted. From this an integrated CHD pathogenetic pathway system was constructed. CHD biomarkers, which are found on these pathways, are the only measurable data to link diet with these CHD pathways. They were thus used to simplify the link between diet and the CHD mechanism. Data were systematically analysed from 294 cohort studies of CHD biomarkers constituting 1 187 350 patients.

Results and discussion

The resulting integrated analysis provides insight into the higher-order interactions underlying CHD and high-glycemic load (HGL) diets. A novel “connection graph” illustrates the measurable relationship between HGL diets and the relative risks attributed to the important CHD serological biomarkers.

The “connection graph” vividly shows that HGL diets not only influence the lipid and metabolic biomarkers, but also the inflammation, coagulation and vascular function biomarkers in an important way.

Conclusion

A focus primarily on the low density lipoprotein cholesterol biomarker for CHD risk has led to the traditional guidelines of CHD dietary recommendations. This has however inadvertently led to HGL diets. The influence of HGL diets on the other CHD biomarkers is not always fully appreciated. Thus, new diets or other interventions which address the full integrated CHD impact, as shown in this paper, are required.

Insulin resistance and adipokine levels correlate with early atherosclerosis - a study in prediabetic patients

Cardiovascular risk of prediabetes is still subject to controversies. We analyzed the associations between insulin resistance, adipokines and incipient atherosclerosis estimated by intima-media thickness (IMT) in a cross-sectional study on 122 prediabetic subjects without clinical signs of atherosclerotic disease. Homeostasis model assessment of insulin resistance (HOMA-IR, calculated as fasting insulin × fasting plasma glucose / 22.5), adiponectin, leptin, leptin-to-adiponectin ratio, carotid and femoral IMT were evaluated. We also assessed other parameters related to insulin resistance and adipokines (HbA_1c, anthropometric and lipid parameters), as they may also influence atherosclerosis. Carotid IMT was correlated to adiponectin and leptin-to-adiponectin ratio (all p < 0.05), but not with HOMA-IR or leptin, while femoral IMT showed no relationship with these factors. After adjusting for leptin, leptin-to-adiponectin ratio, triglycerides, HDL-cholesterol, cholesterol-to-HDL ratio, triglycerides-to-HDL ratio and HbA_1c, IMT values became correlated with HOMA-IR. Adjustment for HOMA-IR induced the appearance of new correlations between adipokines and both IMT values. In conclusion, insulin resistance and adipokines seem related to IMT in prediabetic subjects without clinical signs of arterial obstruction.

Association of classical risk factors and coronary artery disease in type 2 diabetic patients submitted to coronary angiography

BACKGROUND

Coronary artery disease (CAD) is the leading cause of death among individuals with type 2 diabetes (T2DM). T2DM accelerates atherosclerosis alongside classical risk factors such as dyslipidemia and hypertension. This study aims to investigate the association of hyperglycemia and associated risk factors with CAD in outpatients with T2DM undergoing coronary angiography.

METHODS

818 individuals referred to coronary angiography were evaluated for glucose disturbances. After exclusion of those with prediabetes, 347 individuals with T2DM and 94 normoglycemic controls were studied for BMI, blood pressure, fasting plasma glucose, HbA1c, lipids, HOMA, adiponectin, Framingham risk score, number of clinically significant coronary lesions (stenosis > 50%).

RESULTS

Among T2DM subjects, those with CAD (n = 237) had worse glycemic control (fasting glucose 162.3 + 69.8 vs. 143.4 + 48.9 mg/dL, p = 0.004; HbA1c 8.03 + 1.91 vs. 7.59 + 1.55%, p = 0.03), lower HDL (39.2 + 13.2 vs. 44.4 + 15.9 mg/dL, p = 0.003), and higher triglycerides (140 [106-204] vs. 121 [78.5-184.25] mg/dL, p = 0.002), reached more often therapeutic goals for LDL (63.4% vs. 51.4%, p = 0.037) and less often goals for HDL (26.6% vs. 37.3%, p = 0.04), when compared to CAD-free individuals (n = 110). The same differences were not seen in normoglycemic controls. In T2DM subjects HbA1c tertiles were associated with progressively higher number of significant coronary lesions (median number of lesions 2 [A1c < 6.8%]; 2.5 [A1c 6.8-8.2%]; 4 [A1c > 8.2%]; p = 0.01 for trend).

CONCLUSIONS

Classic risk factors such as glycemic control and lipid profile were associated with presence of CAD in T2DM subjects undergoing coronary angiography. Glycemic control is progressively associated with number and extent of coronary lesions in patients with T2DM.

Body mass index and myocardium at risk in patients with acute coronary syndrome

BACKGROUND AND OBJECTIVES

Whilst traditional studies have shown that obese individuals are at a higher risk of cardiovascular events compared to lean subjects, recent studies in patients with acute myocardial infarction (AMI) have suggested that obesity may exert protective effects (the "obesity paradox"). We sought to assess the relationship between body mass index (BMI) and the BARI score (BARIsc), a validated tool used to assess myocardium at risk, in patients with acute coronary syndrome.

PATIENTS AND METHODS

Participants were 116 consecutive patients (mean age, 60.6 years; 97 men) with AMI (68 ST elevated myocardial infarction, STEMI; 48 non-ST elevated myocardial infarction, NSTEMI). Demographics, BMI, risk factors, biochemistry data, left ventricular function, angiographic data and the BARIsc were assessed in every patient.

RESULTS

Multiple linear regression analyses showed that BMI significantly correlated with BARIsc; β=.23, p<0.02. This was found only in the overweight/obese patients, β=.27, p<0.01, but not in patients with normal BMIs, β=0.08, p=0.71.

CONCLUSIONS

An increased body weight is associated with an increased area of myocardium at risk in patients with ACS.

Regular physical exercise as a strategy to improve antioxidant and anti-inflammatory status: benefits in type 2 diabetes mellitus

Over the last 30 years the combination of both a sedentary lifestyle and excessive food availability has led to a significant increase in the prevalence of obesity and aggravation of rates of metabolic syndrome and type 2 diabetes mellitus (T2DM). Several lines of scientific evidence have been demonstrating that a low level of physical activity and decreased daily energy expenditure leads to the accumulation of visceral fat and, consequently, the activation of the oxidative stress/inflammation cascade, which underlies the development of insulin resistant T2DM and evolution of micro, and macrovascular complications. This paper focuses on the pathophysiological pathways associated with the involvement of oxidative stress and inflammation in the development of T2DM and the impact of regular physical exercise (training) as a natural antioxidant and anti-inflammatory strategy to prevent evolution of T2DM and its serious complications.