Skin accumulation of advanced glycation end products is increased in patients with an abdominal aortic aneurysm

A population-based study on hyperinsulinaemia and arterial stiffness in men with and without abdominal aortic aneurysm

Objectives

Patients with type 2 diabetes mellitus (DM) run lower risk for abdominal aortic aneurysm (AAA, aortic diameter ≥ 30 mm) and its complications. We aimed to evaluate associations between disturbances in glucose metabolism and arterial stiffness, AAA, and abdominal aortic diameter in 65-year-old men.

Methods

Forty-eight 65-year-old men with screening-detected AAA and 115 men with normal abdominal aortic diameter underwent examination of glucose metabolism and arterial stiffness.

Results

Men with AAA had higher BMI, waist-hip ratio (WHR), frequency of DM, haemoglobin A1c, smoking exposure, and plasma insulin levels at 0, 60 and 120 min during OGTT compared to those without. The increase in p-insulin (P < 0.001) after OGTT was also higher in men with AAA, adjusted for smoking, WHR, and nadir value of p-insulin. In analyses adjusted for smoking, use of lipid-lowering agents, and WHR, the increase in p-insulin at 2-hours (P = 0.006) after OGTT and p-homocysteine were associated with abdominal aortic diameter. There were no differences between groups in aortic stiffness or skin autofluorescence Advanced Glycation End products.

Conclusion

In this population-based study hyperinsulinaemia as a marker of insulin resistance, but not hyperglycaemia or aortic stiffness, was associated with AAA and abdominal aortic diameter in 65-year-old men.

The role of oxidative stress and hypoxia in renal disease

Oxygen is required to sustain aerobic organisms. Reactive oxygen species (ROS) are constantly released during mitochondrial oxygen consumption for energy production. Any imbalance between ROS production and its scavenger system induces oxidative stress. Oxidative stress, a critical contributor to tissue damage, is well-known to be associated with various diseases. The kidney is susceptible to hypoxia, and renal hypoxia is a common final pathway to end stage kidney disease, regardless of the underlying cause. Renal hypoxia aggravates oxidative stress, and elevated oxidative stress, in turn, exacerbates renal hypoxia. Oxidative stress is also enhanced in chronic kidney disease, especially diabetic kidney disease, through various mechanisms. Thus, the vicious cycle between oxidative stress and renal hypoxia critically contributes to the progression of renal injury. This review examines recent evidence connecting chronic hypoxia and oxidative stress in renal disease and subsequently describes several promising therapeutic approaches against oxidative stress.

Diabetes and aortic aneurysm: current state of the art

Aortic aneurysm is a life-threatening disease due to the risk of aortic rupture. The only curative treatment available relies on surgical approaches; drug-based therapies are lacking, highlighting an unmet need for clinical practice. Abdominal aortic aneurysm (AAA) is frequently associated with atherosclerosis and cardiovascular risk factors including male sex, age, smoking, hypertension, and dyslipidaemia. Thoracic aortic aneurysm (TAA) is more often linked to genetic disorders of the extracellular matrix and the contractile apparatus but also share similar cardiovascular risk factors. Intriguingly, a large body of evidence points to an inverse association between diabetes and both AAA and TAA. A better understanding of the mechanisms underlying the negative association between diabetes and aortic aneurysm could help the development of innovative diagnostic and therapeutic approaches to tackle the disease. Here, we summarize current knowledge on the relationship between glycaemic parameters, diabetes, and the development of aortic aneurysm. Cellular and molecular pathways that underlie the protective effect of diabetes itself and its treatment are reviewed and discussed, along with their potential implications for clinical translation.

Skin autofluorescence predicts major adverse cardiovascular events in patients with type 1 diabetes: a 7-year follow-up study

Background

Advanced glycation end-products play a role in diabetic vascular complications. Their optical properties allow to estimate their accumulation in tissues by measuring the skin autofluorescence (SAF). We searched for an association between SAF and major adverse cardiovascular events (MACE) incidence in subjects with Type 1 Diabetes (T1D) during a 7 year follow-up.

Methods

During year 2009, 232 subjects with T1D were included. SAF measurement, clinical [age, sex, body mass index (BMI), comorbidities] and biological data (HbA1C, blood lipids, renal parameters) were recorded. MACE (myocardial infarction, stroke, lower extremity amputation or a revascularization procedure) were registered at visits in the center or by phone call to general practitioners until 2016.

Results

The participants were mainly men (59.5%), 51.5 ± 16.7 years old, with BMI 25.0 ± 4.1 kg/m², diabetes duration 21.5 ± 13.6 years, HbA1C 7.6 ± 1.1%. LDL cholesterol was 1.04 ± 0.29 g/L, estimated Glomerular Filtration Rates (CKD-EPI): 86.3 ± 26.6 ml/min/1.73 m². Among these subjects, 25.1% were smokers, 45.3% had arterial hypertension, 15.9% had elevated AER (≥ 30 mg/24 h), and 9.9% subjects had a history of previous MACE. From 2009 to 2016, 22 patients had at least one new MACE: 6 myocardial infarctions, 1 lower limb amputation, 15 revascularization procedures. Their SAF was 2.63 ± 0.73 arbitrary units (AU) vs 2.08 ± 0.54 for other patients (p = 0.002). Using Cox-model, after adjustment for age (as the scale time), sex, diabetes duration, BMI, hypertension, smoking status, albumin excretion rates, statin treatment and a previous history of MACE, higher baseline levels of SAF were significantly associated with an increased risk of MACE during follow-up (HR = 4.13 [1.30–13.07]; p = 0.02 for 1 AU of SAF) and Kaplan–Meier curve follow-up showed significantly more frequent MACE in group with SAF upper the median (p = 0.001).

Conclusion

A high SAF predicts MACE in patients with T1D.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0718-8) contains supplementary material, which is available to authorized users.

Role of Ligands of Receptor for Advanced Glycation End Products (RAGE) in Peripheral Artery Disease

Atherosclerotic cardiovascular disease, including peripheral artery disease (PAD), is more common and severe in diabetic patients compared with nondiabetic individuals. Indeed, diabetes is associated with the increased risk of limb amputation and all-cause mortality in patients with symptomatic PAD. Proteins and lipids are nonenzymatically modified by sugars, resulting in the formation and accumulation of advanced glycation end products (AGEs), whose process is accelerated under diabetic conditions, especially patients with a long duration of diabetes. Accumulating evidence shows that nonenzymatic modification by sugars alters the structural integrity of collagens and lipoproteins in large vessels, thereby being involved in vascular stiffness and atherosclerotic plaque instability. Furthermore, engagement of receptor for AGEs (RAGE) with its ligands, such as AGEs, high mobility group box 1, and S100A proteins evokes inflammatory and thrombotic reactions, thus playing a central role in the development and progression of atherosclerotic cardiovascular disease. In this article, we review the pathophysiological role of RAGE ligands in PAD and discuss the clinical utility of measurement of plasma, serum, or tissue RAGE ligands for assessment of the severity and prognosis of PAD. This review suggests that RAGE ligands may be a novel biomarker and also a therapeutic target of PAD, especially in patients with diabetes.

Impaired permeability and antimicrobial barriers in type 2 diabetes skin are linked to increased serum levels of advanced glycation end-product

The incidence of type 2 diabetes mellitus (DM) has been increasing rapidly, and the disease has become a serious sociomedical problem. Many skin problems, such as xerosis, pruritus, skin infections and delayed wound healing, that might be related to chronic impairment of skin barrier function decrease the quality of life in patients with DM. However, the status of the permeability and antimicrobial barrier of the skin in DM remains unknown. This study aimed to elucidate skin barrier impairment in patients with type 2 DM and its pathomechanisms using classic animal models of type 2 DM. Functional studies of the skin barrier and an analysis of stratum corneum (SC) lipids were compared between patients with type 2 DM and age- and sex-matched non-diabetes controls. Also, functional studies on the skin barrier, epidermal lipid analyses, and electron microscopy and biomolecular studies were performed using type 2 DM animal models, db/db and ob/ob mice. Patients with type 2 DM presented with epidermal barrier impairments, including SC hydration, which was influenced by blood glucose control (HbA1c level). In the lipid analysis of SC, ceramides, fatty acids and cholesterol were significantly decreased in patients with type 2 DM compared with controls. Type 2 DM murine models presented with severe hyperglycaemia, impairment of skin barrier homeostasis, decreases in epidermal proliferation and epidermal lipid synthesis, decreases in lamellar body (LB) and epidermal antimicrobial peptides (AMPs), an increase in receptors for advanced glycation end-product (AGE) in the epidermis and an increase in serum AGE. Impairment of the skin barrier was observed in type 2 DM, which results in part from a decrease in epidermal proliferation. Serum AGE and its epidermal receptors were increased in type 2 diabetic mice which display impaired skin barrier parameters such as epidermal lipid synthesis, LB production, epidermal AMP and SC lipids.