Endothelial dysfunction, cellular adhesion molecules and the metabolic syndrome

Over the last two decades, it has become evident that the endothelium is more than an inert, single-cell lining covering the internal surface of blood vessels. Normally, the endothelium actively decreases vascular tone, maintains vascular permeability within narrow bounds, inhibits platelet adhesion and aggregation, limits activation of the coagulation system, and stimulates fibrinolysis. Endothelium dysfunction can be considered present when its functions, either in the basal state or after stimulation, are altered in a way that is inappropriate to the preservation of organ function. Endothelial dysfunction has been associated to many cardiovascular risk factors including diabetes, hypertension and hypercholesterolemia. In addition, endothelial dysfunction may play a crucial role in the development and progression of atherosclerosis. This review will give a brief overview of the different methods to assess endothelial function, and then will focus on the current knowledge on soluble cellular adhesion molecules in relation to the metabolic syndrome and type 2 diabetes

Advanced glycation end products are associated with pulse pressure in type 1 diabetes: the EURODIAB Prospective Complications Study

We investigated the associations of pulse pressure (a measure of arterial stiffness) with the early glycation products hemoglobin A1c (HbA1c) and Amadori albumin and the advanced glycation end products pentosidine, Nepsilon-(carboxymethyl)lysine and Nepsilon-(carboxyethyl)lysine in a large group of type 1 diabetic individuals of the EURODIAB Prospective Complications Study. We did a cross-sectional nested case-control study from the EURODIAB Prospective Complications Study of 543 (278 men) European individuals with type 1 diabetes diagnosed at <36 years of age. We used linear regression analyses to investigate the association of pulse pressure with glycation products. Pulse pressure was significantly associated with plasma levels of Nepsilon-(carboxymethyl)lysine and Nepsilon-(carboxyethyl)lysine but not with HbA1c, Amadori albumin, and urinary levels of pentosidine. Regression coefficients adjusted for age, sex, mean arterial pressure, and duration of diabetes were 0.09 mm Hg (P=0.003) per 1 microM/M lysine Nepsilon-(carboxymethyl)lysine; 0.24 mm Hg (P=0.001) and -0.03 mm Hg (P=0.62) per 1 microM/M lysine Nepsilon-(carboxyethyl)lysine (in individuals with and without complications, respectively; P interaction=0.002); and 0.50 mm Hg (P=0.16) per 1% HbA1c; 0.07 mm Hg (P=0.12) per 1 U/mL Amadori albumin; and 0.77 mm Hg (P=0.48) per 1 nmol/mmol creatinine pentosidine. In young type 1 diabetic individuals, arterial stiffness is strongly associated with the advanced glycation end products Nepsilon-(carboxymethyl)lysine and Nepsilon-(carboxyethyl)lysine. These findings suggest that the formation of advanced glycation end products is an important pathway in the development of arterial stiffness in young type 1 diabetic individuals

Neighbourhood property value and type 2 diabetes mellitus in the Maastricht study: A multilevel study

Objective Low individual socioeconomic status (SES) is known to be associated with a higher risk of type 2 diabetes mellitus (T2DM), but the extent to which the local context in which people live may influence T2DM rates remains unclear. This study examines whether living in a low property value neighbourhood is associated with higher rates of T2DM independently of individual SES. Research design and methods Using cross-sectional data from the Maastricht Study (2010\u20132013) and geographical data from Statistics Netherlands, multilevel logistic regression was used to assess the association between neighbourhood property value and T2DM. Individual SES was based on education, occupation and income. Of the 2,056 participants (aged 40\u201375 years), 494 (24%) were diagnosed with T2DM. Results Individual SES was strongly associated with T2DM, but a significant proportion of the variance in T2DM was found at the neighbourhood level (VPC = 9.2%; 95% CI = 5.0%\u201316%). Participants living in the poorest neighbourhoods had a 2.38 times higher odds ratio of T2DM compared to those living in the richest areas (95% CI = 1.58\u20133.58), independently of individual SES. Conclusions Neighbourhood property value showed a significant association with T2DM, suggesting the usefulness of area-based programmes aimed at improving neighbourhood characteristics in order to tackle inequalities in T2DM

Increased central artery stiffness in impaired glucose metabolism and type 2 diabetes - The Hoorn study

Impaired glucose metabolism (IGM) and type 2 diabetes (DM-2) are associated with high cardiovascular disease risk. Increases in peripheral and central artery stiffness may represent pathophysiologic pathways through which glucose tolerance status leads to cardiovascular disease. Peripheral artery stiffness increases with deteriorating glucose tolerance status, whereas this trend remains unclear for central artery stiffness. Therefore, we investigated the associations between glucose tolerance status and estimates of central arterial stiffness. We performed a population-based study of 619 individuals (normal glucose metabolism, n=261; IGM, n=170; and DM-2, n=188) and assessed central artery stiffness by measuring total systemic arterial compliance, aortic pressure augmentation index, and carotid-femoral transit time. After adjustment for sex, age, heart rate, height, body mass index, and mean arterial pressure, DM-2 was associated with decreased total systemic arterial compliance, increased aortic augmentation index, and decreased carotid-femoral transit time. IGM was borderline significantly associated with decreased total systemic arterial compliance. Respective regression coefficients (95% confidence intervals) for IGM and DM-2 compared with normal glucose metabolism were -0.05 (-0.11 to 0.01) and -0.13 (-0.19 to -0.07) mL/mm Hg for total system carterial compliance; 1.1 (-0.2 to 2.5) and 1.6 (0.2 to 3.0) percentage points for aortic augmentation index; and -0.85 (-5.20 to 3.49) and -4.95 (-9.41 to -0.48) ms for carotid-femoral transit time. IGM and DM-2 are associated with increased central artery stiffness, which is more pronounced in DM-2. Deteriorating glucose tolerance is associated with increased central and peripheral arterial stiffness, which may partly explain why both DM-2 and IGM are associated with increased cardiovascular risk

Association between serum uric acid, aortic, carotid and femoral stiffness among adults aged 40-75 years without and with type 2 diabetes mellitus: The Maastricht Study

Objective: Arterial stiffness may be a mechanism to explain the association between uric acid and cardiovascular disease. We aimed to analyse associations between serum uric acid and regional and local arterial stiffness, and assess potential differences related to sex and glucose metabolism status. Methods: A cross-sectional study was performed in 614 adults [52.6% men; mean age 58.7 +/- 8.5 years; 23.2% type 2 diabetes mellitus (by design)] from The Maastricht Study. Arterial stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV), distensibility, and compliance coefficient of the carotid and femoral artery, and carotid artery Young's elastic modulus. Results: Higher uric acid (per SD of 74 mu mol/l) was associated with greater stiffness indicated by a significantly higher cfPWV [beta = 0.216 (95% confidence interval 0.061, 0.372); P = 0.006] and lower carotid distensibility coefficient [beta = -0.633 (95% confidence interval -1.099, -0.166); P = 0.008] after adjustment for sex, age, and glucose metabolism status. Associations lost significance after adjusting for mean arterial pressure, BMI, waist, smoking status, heart rate, total : high-density lipoprotein cholesterol ratio, triglycerides, estimated glomerular filtration rate, use of lipid-lowering, antihypertensive, and diabetes medication, and use of secondary uricosurics. No associations were found between uric acid and carotid compliance coefficient, carotid Young's elastic modulus, or stiffness of the femoral artery. A significant interaction (P <0.10) with glucose metabolism status was found for cfPWV. However, none of the stratified associations were significant. There was no interaction with sex. Conclusion: Uric acid was not significantly associated with stiffness of the aorta, or the carotid or femoral artery among adults aged 40-75 years without and with type 2 diabetes mellitus

Interplay of White Matter Hyperintensities, Cerebral Networks, and Cognitive Function in an Adult Population:Diffusion-Tensor Imaging in the Maastricht Study

Background: Lesions of cerebral small vessel disease, such as white matter hyperintensities (WMHs) in individuals with cardiometabolic risk factors, interfere with the trajectories of the white matter and eventually contribute to cognitive decline. However, there is no consensus yet about the precise underlying topological mechanism. Purpose: To examine whether WMH and cognitive function are associated and whether any such association is mediated or explained by structural connectivity measures in an adult population. In addition, to investigate underlying local abnormalities in white matter by assessing the tract-specific WMH volumes and their tract-specific association with cognitive function. Materials and Methods: In the prospective type 2 diabetes-enriched population-based Maastricht Study, structural and diffusion-tensor MRI was performed (December 2013 to February 2017). Total and tract-specific WMH volumes; network measures; cognition scores; and demographic, cardiovascular, and lifestyle characteristics were determined. Multivariable linear regression and mediation analyses were used to investigate the association of WMH volume, tract-specific WMH volumes, and network measures with cognitive function. Associations were adjusted for age, sex, education, diabetes status, and cardiovascular risk factors. Results: A total of 5083 participants (mean age, 59 years +/- 9 [standard deviation]; 2592 men; 1027 with diabetes) were evaluated. Larger WMH volumes were associated with stronger local (standardized beta coefficient, 0.065; P Conclusion: White matter hyperintensity volume, local network efficiency, and information processing speed scores are interrelated, and local network properties explain lower cognitive performance due to white matter network alterations. (C) RSNA, 202

Associations of Advanced Glycation End-Products With Cognitive Functions in Individuals With and Without Type 2 Diabetes: The Maastricht Study

Context: Advanced glycation end-products (AGEs) are thought to be involved in the pathogenesis of Alzheimer's disease. AGEs are products resulting from nonenzymatic chemical reactions between reduced sugars and proteins, which accumulate during natural aging, and their accumulation is accelerated in hyperglycemic conditions such as type 2 diabetes mellitus. Objective: The objective of the study was to examine associations between AGEs and cognitive functions. Design, Setting, and Participants: This study was performed as part of the Maastricht Study, a population-based cohort study in which, by design, 215 participants (28.1%) had type 2 diabetes mellitus. Main Outcome Measures: We examined associations of skin autofluorescence (SAF) (n = 764), an overall estimate of skin AGEs, and specific plasma protein-bound AGEs (n = 781) with performance on tests for global cognitive functioning, information processing speed, verbal memory (immediate and delayed word recall), and response inhibition. Results: After adjustment for demographics, diabetes, smoking, alcohol, waist circumference, total cholesterol/high-density lipoprotein cholesterol ratio, triglycerides, and lipid-lowering medication use, higher SAF was significantly associated with worse delayed word recall (regression coefficient, b = - 0.44; P = .04), and response inhibition (b = 0.03; P = .04). After further adjustment for systolic blood pressure, cardiovascular disease, estimated glomerular filtration rate, and depression, associations were attenuated (delayed word recall, b = - 0.38, P = .07; response inhibition, b = 0.02, P = .07). Higher pentosidine levels were associated with worse global cognitive functioning (b = - 0.61; P = .04) after full adjustment, but other plasma AGEs were not. Associations did not differ between individuals with and without diabetes. Conclusion: We found inverse associations of SAF (a noninvasive marker for tissue AGEs) with cognitive performance, which were attenuated after adjustment for vascular risk factors and depression

Exercise SBP response and incident depressive symptoms: The Maastricht Study

Objective : An exaggerated exercise SBP, which is potentially modifiable, may be associated with incident depressive symptoms via an increased pulsatile pressure load on the brain. However, the association between exaggerated exercise SBP and incident depressive symptoms is unknown. Therefore, we examined whether exaggerated exercise SBP is associated with a higher risk of depressive symptoms over time. Methods : We used longitudinal data from the population-based Maastricht Study, with only individuals free of depressive symptoms at baseline included (n = 2121; 51.3% men; age 59.5 +/- 8.5 years). Exercise SBP was measured at baseline with a submaximal exercise cycle test. We calculated a composite score of exercise SBP based on four standardized exercise SBP measures: SBP at moderate workload, SBP at peak exercise, SBP change per minute during exercise and SBP 4 min after exercise. Clinically relevant depressive symptoms were determined annually at follow-up and defined as a Patient Health Questionnaire score of at least 10. Results : After a mean follow-up of 3.9 years, 175 participants (8.3%) had incident clinically relevant depressive symptoms. A 1 SD higher exercise SBP composite score was associated with a higher incidence of clinically relevant depressive symptoms [hazard ratio: 1.27 (95% confidence interval: 1.04-1.54)]. Results were adjusted for age, sex, education level, glucose metabolism status, lifestyle, cardiovascular risk factors, resting SBP and cardiorespiratory fitness. Conclusion : A higher exercise SBP response is associated with a higher incidence of clinically relevant depressive symptoms

A single site in human β-hexosaminidase A binds both 6-sulfate-groups on hexosamines and the sialic acid moiety of GM2 ganglioside

AbstractHuman β-hexosaminidase A (Hex A) (αβ) is composed of two subunits whose primary structures are ∼60% identical. Deficiency of either subunit results in severe neurological disease due to the storage of GM2 ganglioside; Tay–Sachs disease, α deficiency, and Sandhoff disease, β deficiency. Whereas both subunits contain active sites only the α-site can efficiently bind negatively charged 6-sulfated hexosamine substrates and GM2 ganglioside. We have recently identified the αArg424 as playing a critical role in the binding of 6-sulfate-containing substrates, and βAsp452 as actively inhibiting their binding. To determine if these same residues affect the binding of the sialic acid moiety of GM2 ganglioside, an αArg424Gln form of Hex A was expressed and its kinetics analyzed using the GM2 activator protein:[3H]-GM2 ganglioside complex as a substrate. The mutant showed a ∼3-fold increase in its Km for the complex. Next a form of Hex B (ββ) containing a double mutation, βAspLeu453AsnArg (duplicating the α-aligning sequences), was expressed. As compared to the wild type (WT), the mutant exhibited a >30-fold increase in its ability to hydrolyze a 6-sulfated substrate and was now able to hydrolyze GM2 ganglioside when the GM2 activator protein was replaced by sodium taurocholate. Thus, this α-site is critical for binding both types of negatively charge substrates