Undiagnosed coronary artery disease in long-term type 1 diabetes. The Dialong study

Screening for Subclinical Atherosclerosis and the Prediction of Cardiovascular Events in People with Type 1 Diabetes

People with type 1 diabetes (T1D) have a high cardiovascular disease (CVD) risk, which remains the leading cause of death in this population. Despite the improved control of several classic risk factors, particularly better glycaemic control, cardiovascular morbidity and mortality continue to be significantly higher than in the general population. In routine clinical practice, estimating cardiovascular risk (CVR) in people with T1D using scales or equations is often imprecise because much of the evidence comes from pooled samples of people with type 2 diabetes (T2D) and T1D or from extrapolations of studies performed on people with T2D. Given that T1D onsets at a young age, prolonged exposure to the disease and its consequences (e.g., hyperglycaemia, changes in lipid metabolism or inflammation) have a detrimental impact on cardiovascular health. Therefore, it is critical to have tools that allow for the early identification of those individuals with a higher CVR and thus be able to make the most appropriate management decisions in each case. In this sense, atherosclerosis is the prelude to most cardiovascular events. People with diabetes present pathophysiological alterations that facilitate atherosclerosis development and that may imply a greater vulnerability of atheromatous plaques. Screening for subclinical atherosclerosis using various techniques, mainly imaging, has proven valuable in predicting cardiovascular events. Its use enables the reclassification of CVR and, therefore, an individualised adjustment of therapeutic management. However, the available evidence in people with T1D is scarce. This narrative review provides and updated overview of the main non-invasive tests for detecting atherosclerosis plaques and their association with CVD in people with T1D.

Metabolic predictors of pain, fatigue, depression and quality of life in people with long-term type 1 diabetes-the Dialong study

AIM

To examine associations of metabolic parameters (mean 30 years' time-weighted HbA_1c and low-density lipoprotein-cholesterol [LDL-c], current methionine sulfoxide [MetSO], advanced glycation end products [AGEs], inflammatory markers and hypoglycaemia) with pain, fatigue, depression and quality of life (QoL) in people with long-term type 1 diabetes.

METHODS

A total of 104 persons with type 1 diabetes ≥45 years duration were included. Participants completed questionnaires measuring bodily pain (RAND-36 bodily pain domain with lower scores indicate higher levels of bodily pain), fatigue (Fatigue Questionnaire), depression (Patient Health Questionnaire), overall QoL (World Health Organization Quality of Life-BREF) and diabetes-related QoL (Audit of Diabetes-Dependent Quality of Life). In this observational study, mean time-weighted HbA_1c and LDL-c were calculated based on longitudinal measures obtained from medical records of up to 34 years, while current HbA_1c , LDL-c and inflammatory markers were analysed in blood samples and collagen MetSO and AGEs in skin biopsies. History of hypoglycaemia was self reported. Associations between metabolic parameters and questionnaire scores were analysed using linear regression analyses and are reported as standardized regression coefficients (beta).

RESULTS

Of the metabolic variables, higher mean time-weighted HbA_1c was associated with higher levels of bodily pain and total fatigue (beta [p-value]) -0.3 (<0.001) and 0.2 (0.001).

CONCLUSIONS

Long-term chronic hyperglycaemia may have a negative influence on pain and fatigue in people with type 1 diabetes. These results may assist health care workers in emphasizing the importance of strict glycaemic control in people with diabetes and identifying and treating type 1 diabetes-related pain and fatigue.

Characteristics and outcomes of patients with type 1 diabetes admitted with acute coronary syndromes

AIMS

This study explored characteristics and outcomes of patients with type 1 diabetes mellitus (T1DM) and acute coronary syndromes (ACS).

METHODS

A retrospective analysis of patients with T1DM admitted with ACS to an Australian hospital was conducted. Risk factor targets were defined by 2021 European Society of Cardiology Guidelines. Outcomes were defined as an adverse cardiovascular event (ACS, unplanned revascularisation, heart failure, stroke, or cardiovascular death) or all-cause mortality within six-months after discharge.

RESULTS

61 patients were included [age 58.5 ± 12.8 years, 39 % female]. Dyslipidaemia (85 %), hypertension (75 %), smoking (28 %), prior coronary artery disease (CAD) (44 %), and microvascular complications (62 %) were common. HbA1c, low-density lipoprotein cholesterol, and blood pressure targets were attained in 12 %, 36 % and 47 %, respectively. ST-elevation myocardial infarction (65 % versus 7 %, p < 0.001) and revascularisation (77 % versus 41 %, p = 0.008) were more common in those without prior CAD. Peak inpatient blood glucose correlated directly with peak troponin (p = 0.011) and inversely with left ventricular ejection fraction (p = 0.027). Nineteen patients experienced an adverse six-month outcome, with peripheral neuropathy (p = 0.039) and in-hospital hypoglycaemia (p = 0.012) being independent predictors.

CONCLUSIONS

Patients with T1DM and ACS often do not meet guideline targets for cardiovascular risk factors, and frequently present with transmural infarctions. Dysglycemia and microvascular complications predict poorer outcomes.

NETosis in Long-Term Type 1 Diabetes Mellitus and Its Link to Coronary Artery Disease

Background

Neutrophil extracellular traps NETs have been linked to glucose and the pathogenesis of type 1 diabetes mellitus (T1DM). NETs also play a role in vascular inflammation and the development of coronary artery disease (CAD). The role of NETs in CAD progression in patients with long-term T1DM is unclear. We aimed to 1) investigate whether levels of circulating NETs markers were elevated in long-term T1DM subjects compared to controls, and 2) explore whether levels of NETs were related to the presence of CAD.

Material and Methods

102 patients with > 45 years of T1DM and 75 age-matched controls were enrolled in a cross-sectional study. Median age was 62 years. Computed tomography coronary angiography (CTCA) was performed in 148 subjects without established coronary heart disease. For the current study, CAD was defined as a coronary artery stenosis >50%. Double-stranded deoxyribonucleic acid (dsDNA) was measured by a nucleic acid stain, myeloperoxidase-DNA (MPO-DNA), citrullinated histone 3 (H3Cit) and peptidylarginine deiminase 4 (PAD4) by ELISAs, while gene expression of PAD4 was measured in leukocytes from PAXgene tubes.

Results

Circulating MPO-DNA levels were significantly lower in patients with T1DM than in controls (0.17 vs 0.29 OD, p<0.001), while dsDNA, H3Cit, PAD4 and gene expression of PAD4 did not differ with respect to the presence of T1DM. There were no significant associations between NETs markers and HbA1c in the T1DM group. None of the NETs markers differed according to the presence of CAD in patients with T1DM. While all circulating NETs markers correlated significantly with circulating neutrophils in the control group (r=0.292-393, p<0.014), only H3Cit and PAD4 correlated with neutrophils in the T1DM group (r= 0.330-0.449, p ≤ 0.001).

Conclusions

In this cross-sectional study of patients with long-term T1DM and age-matched controls, circulating NETs levels were not consistently associated with the presence of T1DM or glycemic status, and did not differ according to the presence of CAD in patients with T1DM. Our results entail the possibility of altered neutrophil function and reduced NETosis in T1DM. This warrants further investigation.

Reduced leukocyte telomere lengths and sirtuin 1 gene expression in long-term survivors of type 1 diabetes: A Dialong substudy

AIMS/INTRODUCTION

The shortening of leukocyte telomere length with age has been associated with coronary disease, whereas the association with type 1 diabetes is unclear. We aimed to explore telomere lengths in diabetes patients with regard to coronary artery disease, compared with healthy controls. The longevity factors sirtuin 1 and growth-differentiating factor 11 were investigated accordingly.

MATERIALS AND METHODS

We carried out a cross-sectional study of 102 participants with long-term type 1 diabetes and 75 controls (mean age 62 and 63 years, respectively), where 88 cases and 60 controls without diagnosed coronary artery disease completed computed tomography coronary angiography. Telomere lengths and gene expression of sirtuin 1 and growth-differentiating factor 11 were quantified in leukocytes.

RESULTS

Telomere lengths and sirtuin 1 were reduced in diabetes patients versus controls, medians (25th to 75th percentiles): 0.97 (0.82-1.15) versus 1.08 (0.85-1.29) and 0.88 (0.65-1.14) vs 1.01 (0.78-1.36), respectively, adjusted P < 0.05, both. Previous coronary artery disease in diabetes patients (n = 15) was associated with lower sirtuin 1 and growth-differentiating factor 11 messenger ribonucleic acid expression (adjusted P < 0.03, both). In the combined diabetes and control group, previous artery coronary disease (n = 18) presented with significantly shorter telomeres (adjusted P = 0.038). Newly diagnosed obstructive coronary artery disease, defined as >50% stenosis, was not associated with the investigated variables.

CONCLUSIONS

Long-term type 1 diabetes presented with reduced telomeres and sirtuin 1 expression, with additional reduction in diabetes patients with previous coronary artery disease, showing their importance for cardiovascular disease development with potential as novel biomarkers in diabetes and coronary artery disease.

Autoantibodies Against Methylglyoxal-Modified Apolipoprotein B100 and ApoB100 Peptide Are Associated With Less Coronary Artery Atherosclerosis and Retinopathy in Long-Term Type 1 Diabetes

OBJECTIVE

Methylglyoxal (MGO), a reactive aldehyde forming advanced glycation end products (AGEs), is increased in diabetes and recognized by the immune system, resulting in anti-AGE-specific autoantibodies. The association of these immune responses with macro- and microvascular complications in type 1 diabetes remains unclarified. We investigated associations between MGO-modified apolipoprotein B100 (apoB100) and apoB100 peptide 5 (MGO-p5) autoantibodies and coronary atherosclerosis and retinopathy in type 1 diabetes.

RESEARCH DESIGN AND METHODS

IgM and IgG against MGO-apoB100 and MGO-p5 were measured by ELISA in plasma from 103 subjects with type 1 diabetes and 63 control subjects (Dialong study) and in a replication cohort of 27 subjects with type 1 diabetes (Oslo study). Coronary atherosclerosis was assessed by computed tomography coronary angiography or intravascular ultrasound. Retinopathy was classified by retinal photos.

RESULTS

MGO-apoB100 IgM and MGO-p5 IgM levels were higher in subjects with diabetes with no coronary artery stenosis compared with subjects with significant stenosis (median [interquartile range]: 96.2 arbitrary units [AU] [71-126.8] vs. 54 AU [36.1-85.4], P = 0.003 for MGO-apoB100; and 77.4 AU [58-106] vs. 36.9 AU [28.9-57.4], P = 0.005 for MGO-p5). MGO-apoB100 IgM and MGO-p5 IgM were associated with less severe coronary stenosis after adjusting for confounders (odds ratio 0.2 [95% CI 0.05-0.6], P = 0.01; and 0.22 [0.06-0.75], P = 0.02). The inverse association of MGO-p5 IgM and coronary stenosis was confirmed in the replication cohort. Subjects with proliferative retinopathy had significantly lower MGO-apoB100 IgM and MGO-p5 IgM than those with background retinopathy.

CONCLUSIONS

Autoantibodies against AGE-modified apoB100 are inversely associated with coronary atherosclerosis and proliferative retinopathy, suggesting vascular protective effects of these autoantibodies in type 1 diabetes.

Discoveries from the study of longstanding type 1 diabetes

Award programmes that acknowledge the remarkable accomplishments of long-term survivors with type 1 diabetes have naturally evolved into research programmes to determine the factors associated with survivorship and resistance to chronic complications. In this review, we present an overview of the methodological sources of selection bias inherent in survivorship research (selection of those with early-onset diabetes, incidence-prevalence bias and bias from losses to follow-up in cohort studies) and the breadth and depth of literature focusing on this special study population. We focus on the learnings from the study of longstanding type 1 diabetes on discoveries about the natural history of insulin production loss and microvascular complications, and mechanisms associated with them that may in future offer therapeutic targets. We detail descriptive findings about the prevalence of preserved insulin production and resistance to complications, and the putative mechanisms associated with such resistance. To date, findings imply that the following mechanisms exist: strategies to maintain or recover beta cells and their function; activation of specific glycolytic enzymes such as pyruvate kinase M2; modification of AGE production and processing; novel mechanisms for modification of renin-angiotensin-aldosterone system activation, in particular those that may normalise afferent rather than efferent renal arteriolar resistance; and activation and modification of processes such as retinol binding and DNA damage checkpoint proteins. Among the many clinical and public health insights, research into this special study population has identified putative mechanisms that may in future serve as therapeutic targets, knowledge that likely could not have been gained without studying long-term survivors.

Collagen methionine sulfoxide and glucuronidine/LW-1 are markers of coronary artery disease in long-term survivors with type 1 diabetes. The Dialong study

Objectives

Type 1 diabetes is a risk factor for coronary heart disease. The underlying mechanism behind the accelerated atherosclerosis formation is not fully understood but may be related to the formation of oxidation products and advanced glycation end-products (AGEs). We aimed to examine the associations between the collagen oxidation product methionine sulfoxide; the collagen AGEs methylglyoxal hydroimidazolone (MG-H1), glucosepane, pentosidine, glucuronidine/LW-1; and serum receptors for AGE (RAGE) with measures of coronary artery disease in patients with long-term type 1 diabetes.

Methods

In this cross-sectional study, 99 participants with type 1 diabetes of ≥ 45-year duration and 63 controls without diabetes had either established coronary heart disease (CHD) or underwent Computed Tomography Coronary Angiography (CTCA) measuring total, calcified and soft/mixed plaque volume. Skin collagen methionine sulfoxide and AGEs were measured by liquid chromatography-mass spectrometry and serum sRAGE/esRAGE by ELISA.

Results

In the diabetes group, low levels of methionine sulfoxide (adjusted for age, sex and mean HbA_1c) were associated with normal coronary arteries, OR 0.48 (95% CI 0.27–0.88). Glucuronidine/LW-1 was associated with established CHD, OR 2.0 (1.16–3.49). MG-H1 and glucuronidine/LW-1 correlated with calcified plaque volume (r = 0.23–0.28, p<0.05), while pentosidine correlated with soft/mixed plaque volume (r = 0.29, p = 0.008), also in the adjusted analysis.

Conclusions

Low levels of collagen-bound methionine sulfoxide were associated with normal coronary arteries while glucuronidine/LW-1 was positively associated with established CHD in long-term type 1 diabetes, suggesting a role for metabolic and oxidative stress in the formation of atherosclerosis in diabetes.

Increased Plasma Soluble Interleukin-2 Receptor Alpha Levels in Patients With Long-Term Type 1 Diabetes With Vascular Complications Associated With IL2RA and PTPN2 Gene Polymorphisms

Type 1 diabetes (T1D) is largely considered an autoimmune disease leading to the destruction of insulin-producing pancreatic β cells. Further, patients with T1D have 3-4-fold increased risk of developing micro- and macrovascular complications. However, the contribution of immune-related factors contributing to these diabetes complications are poorly understood. Individuals with long-term T1D who do not progress to vascular complications offer a great potential to evaluate end-organ protection. The aim of the present study was to investigate the association of inflammatory protein levels with vascular complications (retinopathy, nephropathy, cardiovascular disease) in individuals with long-term T1D compared to individuals who rapidly progressed to complications. We studied a panel of inflammatory markers in plasma of patients with long-term T1D with (n = 81 and 26) and without (n = 313 and 25) vascular complications from two cross-sectional Scandinavian cohorts (PROLONG and DIALONG) using Luminex technology. A subset of PROLONG individuals (n = 61) was screened for circulating immune cells using multicolor flow cytometry. We found that elevated plasma levels of soluble interleukin-2 receptor alpha (sIL-2R) were positively associated with the complication phenotype. Risk carriers of polymorphisms in the IL2RA and PTPN2 gene region had elevated plasma levels of sIL-2R. In addition, cell surface marker analysis revealed a shift from naïve to effector T cells in T1D individuals with vascular complications as compared to those without. In contrast, no difference between the groups was observed either in IL-2R cell surface expression or in regulatory T cell population size. In conclusion, our data indicates that IL2RA and PTPN2 gene variants might increase the risk of developing vascular complications in people with T1D, by affecting sIL-2R plasma levels and potentially lowering T cell responsiveness. Thus, elevated sIL-2R plasma levels may serve as a biomarker in monitoring the risk for developing diabetic complications and thereby improve patient care.

Cardiovascular Risk in Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is associated with premature cardiovascular disease (CVD), but the underlying mechanisms remain poorly understood. The American Diabetes Association and the European Association for the Study of Diabetes recently updated their position statement on the management of type 2 diabetes mellitus (T2DM) to include additional focus on cardiovascular risk; improved management of risk factors in T1DM is also needed. There are important differences in the pathophysiology of CVD in T1DM and T2DM. Hyperglycaemia appears to have a more profound effect on cardiovascular risk in T1DM than T2DM, and other risk factors appear to cause a synergistic rather than additive effect, so achievement of treatment targets for all recognized risk factors is crucial to reducing cardiovascular risk. Here we discuss the evidence for addressing established cardiovascular risk factors, candidate biomarkers and surrogate measurements, and possible interventions.

Coronary plaque characteristics and epicardial fat tissue in long term survivors of type 1 diabetes identified by coronary computed tomography angiography

OBJECTIVES

The aim was to assess coronary atherosclerosis, plaque morphology and associations to cardiovascular risk factors and epicardial adipose tissue (EAT) in patients with long duration of type 1 diabetes mellitus (T1DM).

MATERIALS AND METHODS

Eighty-eight patients with ≥ 45 year T1DM duration and 60 controls underwent coronary CT angiography (CCTA) for evaluation of coronary artery plaque volume (total, calcified or mixed/soft), coronary artery calcification score (CAC) and EAT.

RESULTS

Plaques were detected in 75 (85%) T1DM patients and 28 (47%) controls, p < 0.01. Median (interquartile range) plaque volume (mm³) in T1DM vs. controls was: 21.0 (1.0-66.0) vs. 0.2 (0.0-7.1), p < 0.01 for calcified, 0.0 (0.0-8.7) vs. 0.0 (0.0-0.0), p < 0.01 for soft/mixed and 29.5 (3.9-95.8) vs. 0.4 (0.0-7.4), p < 0.01 for total plaque volume. Median CAC was 128 (13-671) vs. 1 (0.0-39.0), p < 0.01 in T1DM vs. controls. Median EAT volume did not differ between the groups; 52.3 (36.1-65.5) cm³ vs. 55 (38.3-79.6), p = 0.20. No association between CAC or plaque volumes and EAT were observed. Low time-weighted LDL-cholesterol and HbA1c for 30 years were associated with having plaque volume < 25th percentile, OR (95% CI) 0.18 (0.05-0.70), p = 0.01 and 0.45 (0.20-1.00), p < 0.05, respectively. Time-weighted LDL-c was linearly associated with CAC (beta 0.82 (95% CI 0.03-1.62), p = 0.04) and total plaque volume (beta 0.77 (95% CI 0.19-1.36), p = 0.01).

CONCLUSION

Long-term survivors of T1DM have a higher prevalence of coronary atherosclerosis compared to controls. Low LDL-cholesterol and HbA1c over time have a protective effect on coronary atherosclerosis. EAT volume was not associated with coronary atherosclerosis in T1DM patients.