Anne Hiukka

Insulin resistance and adiposity correlate with acute-phase reaction and soluble cell adhesion molecules in type 2 diabetes

OBJECTIVE To investigate the relationship of inflammation and endothelial activation with insulin resistance and adiposity in type 2 diabetes. METHODS AND RESULTS Hundred and thirty-four (45 female) type 2 diabetic subjects aged 50-75 in the Fenofibrate Intervention and Event Lowering in Diabetes Study in Helsinki were examined before fenofibrate intervention. Fasting levels of circulating intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) (vascular cell adhesion molecule), ultra-sensitive C-reactive protein (CRP), human serum amyloid A (hSAA), interleukin-6 (IL-6), macrophage colony-stimulating factor (M-CSF), secretory phospholipase A(2) IIA (PLA(2)), total, HDL and LDL cholesterol, triglycerides, P-glucose, HbA1c, and serum free insulin were determined. Insulin resistance was assessed by the homeostasis model. HOMA IR correlated significantly with all measures of adiposity and markers of inflammation and endothelial dysfunction. BMI was significantly associated with inflammation and endothelial activation, but with neither lipoproteins nor glycaemic control. After controlling for age, gender and BMI, HbA1c correlated significantly with CRP, hSAA, ICAM-1, E-selectin, and HOMA IR. HDL cholesterol correlated inversely with IL-6, M-CSF, E-selectin, and HOMA IR. HbA1c, phospholipase A(2), VCAM-1, and HDL cholesterol remained independent determinants of HOMA IR in the linear regression analysis controlled for age, gender, and BMI. CONCLUSION Endothelial activation and acute-phase reaction correlate with insulin resistance and obesity in type 2 diabetic patients.

ApoCIII-Enriched LDL in Type 2 Diabetes Displays Altered Lipid Composition, Increased Susceptibility for Sphingomyelinase, and Increased Binding to Biglycan

OBJECTIVE Apolipoprotein CIII (apoCIII) is an independent risk factor for cardiovascular disease, but the molecular mechanisms involved are poorly understood. We investigated potential proatherogenic properties of apoCIII-containing LDL from hypertriglyceridemic patients with type 2 diabetes. RESEARCH DESIGN AND METHODS LDL was isolated from control subjects, subjects with type 2 diabetes, and apoB transgenic mice. LDL-biglycan binding was analyzed with a solid-phase assay using immunoplates coated with biglycan. Lipid composition was analyzed with mass spectrometry. Hydrolysis of LDL by sphingomyelinase was analyzed after labeling plasma LDL with [3H]sphingomyelin. ApoCIII isoforms were quantified after isoelectric focusing. Human aortic endothelial cells were incubated with desialylated apoCIII or with LDL enriched with specific apoCIII isoforms. RESULTS We showed that enriching LDL with apoCIII only induced a small increase in LDL-proteoglycan binding, and this effect was dependent on a functional site A in apoB100. Our findings indicated that intrinsic characteristics of the diabetic LDL other than apoCIII are responsible for further increased proteoglycan binding of diabetic LDL with high-endogenous apoCIII, and we showed alterations in the lipid composition of diabetic LDL with high apoCIII. We also demonstrated that high apoCIII increased susceptibility of LDL to hydrolysis and aggregation by sphingomyelinases. In addition, we demonstrated that sialylation of apoCIII increased with increasing apoCIII content and that sialylation of apoCIII was essential for its proinflammatory properties. CONCLUSIONS We have demonstrated a number of features of apoCIII-containing LDL from hypertriglyceridemic patients with type 2 diabetes that could explain the proatherogenic role of apoCIII.

Low‐grade inflammation, endothelial activation and carotid intima‐media thickness in type 2 diabetes

Objectives.  The objective of this study was to assess the relationship between inflammation, endothelial activation and incipient atherosclerosis in type 2 diabetes.

Effects of Long-Term Fenofibrate Treatment on Markers of Renal Function in Type 2 Diabetes: The FIELD Helsinki substudy

OBJECTIVE Although fenofibrate was associated with less progression of albuminuria in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study, it is unknown if it has any effect on renal function. We explored if there were changes in commonly available markers of renal function during fenofibrate treatment in the FIELD Helsinki cohort excluding statin users. RESEARCH DESIGN AND METHODS One hundred and seventy subjects with type 2 diabetes were randomly assigned to micronized fenofibrate (200 mg/day) or placebo for 5 years. In this substudy, we measured several markers of albumin excretion and renal function. RESULTS After intensified treatment, blood pressure and fasting glucose decreased in both groups while A1C remained at 7.2%. Plasma creatinine increased with fenofibrate while urine creatinine remained comparable between the groups, resulting in significant decreases in both creatinine clearance and estimated glomerular filtration rate (eGFR) by the Modification of Diet in Renal Disease (MDRD)-4 and Cockroft-Gault equations in the fenofibrate group. Cystatin C increased during fenofibrate treatment. Urinary albumin-to-creatinine ratio and diurnal urine protein remained unchanged, whereas overnight urinary albumin excretion rate showed minor decreases in both groups. CONCLUSIONS We report concomitant decreases in creatinine clearance and eGFR by fenofibrate. These changes complicate the clinical surveillance during fenofibrate treatment. We could not demonstrate the beneficial effects of fenofibrate on albumin excretion. A novel finding is the increase of cystatin C in type 2 diabetic patients during fenofibrate treatment. The clinical relevance of the changes needs to be assessed in a long-term outcome study of renal function.

Decreased High-Density Lipoprotein (HDL) Particle Size, Preβ-, and Large HDL Subspecies Concentration in Finnish Low-HDL Families Relationship With Intima-Media Thickness

Objective—High-density lipoprotein (HDL) cholesterol correlates inversely with the risk of coronary heart disease (CHD). The precise antiatherogenic mechanisms of HDL subspecies are not thoroughly elucidated. We studied the relationship between carotid intima-media thickness (IMT) and HDL subspecies distribution in Finnish families with low HDL cholesterol and premature CHD. Methods and Results—Altogether, 148 members of Finnish low-HDL families and 133 healthy control subjects participated in our study. HDL particle size was significantly smaller in affected family members (HDL ≤10th Finnish age-sex specific percentile) compared with unaffected family members and control subjects (9.1±0.04 nm versus 9.5±0.05 nm, P<0.0001, versus 9.8±0.03 nm, P<0.0001 [mean±SE]). Large HDL2b particles as well as pre&bgr;-HDL concentration were significantly decreased among the affected family members. Mean IMT was significantly higher in the affected family members than in the control subjects (0.85±0.01 mm versus 0.79±0.01 mm; P<0.0001). Age, HDL2b, systolic blood pressure, and pre&bgr;-HDL were significant independent determinants of mean IMT. Conclusions—The decreased levels of HDL2b and pre&bgr;-HDL reflect the potentially efflux-deficient HDL subspecies profile in the affected low-HDL family members. Decreased HDL particle size caused by the decrease of plasma concentration of HDL2b and decreased pre&bgr;-HDL levels correlate with increased IMT.

Alterations of lipids and apolipoprotein CIII in very low density lipoprotein subspecies in type 2 diabetes

Aims/hypothesisVery low density lipoprotein (VLDL) particles are heterogeneous, comprising two main subspecies, VLDL 1 (Sf 60-400) and VLDL 2 (Sf 20-60). The aim of the study was to examine the distribution and composition of VLDL subspecies in type 2 diabetes.Subjects, materials and methodsWe studied the composition and concentration of triglyceride-rich lipoproteins (TRLs) in 217 type 2 diabetic patients and 93 control subjects between 50 and 75 years of age. Lipoprotein subspecies were separated by density-gradient ultracentrifugation. Apolipoprotein (apo) CIII and apo E in plasma and apo CIII in TRL subspecies were measured by nephelometry and apo CII in serum by a commercial kit using a single radial immunodiffusion method.ResultsThe concentrations of VLDL 1, VLDL 2 and intermediate density lipoprotein were significantly increased in type 2 diabetes subjects, the change being most marked for VLDL 1. There was a strong linear correlation between VLDL 1 triglycerides and plasma triglycerides in both groups (r=0.879, p<0.001 and r=0.899, p<0.001). Diabetic subjects had markedly higher plasma ratios of apo CII:apo CIII and apo CIII:apo E. Despite elevated plasma apo CIII, type 2 diabetic subjects had a relative deficiency of apo CIII in all TRL subspecies, suggesting profound disturbances of apo CIII metabolism.Conclusions/interpretationThe elevation of VLDL 1 triglycerides is the major determinant of plasma triglyceride concentration in normal subjects and in type 2 diabetic individuals. Both apo CIII and apo E metabolism are disturbed in type 2 diabetes.

Long-Term Effects of Fenofibrate on Carotid Intima-Media Thickness and Augmentation Index in Subjects With Type 2 Diabetes Mellitus

OBJECTIVES The aim of this substudy was to ascertain whether long-term treatment with fenofibrate reduces surrogate measures of atherosclerosis, biomarkers of inflammation, and endothelial activation in patients with type 2 diabetes. BACKGROUND Some fibrates may decrease cardiovascular events, improve endothelial function, and reduce levels of acute-phase proteins. In the FIELD (Fenofibrate Intervention and Event Lowering in Diabetes) study, fenofibrate failed to decrease the primary end point of coronary events in patients with type 2 diabetes. METHODS A total of 170 patients with type 2 diabetes of the FIELD Helsinki cohort were randomly assigned to micronized fenofibrate 200 mg/day or placebo in a double-blind design. Carotid intima-media thickness (IMT) and the augmentation index (a measure of large artery stiffness) were measured at baseline and at second- and fifth-year visits. Plasma levels of interleukin (IL)-6, C-reactive protein (CRP), serum amyloid A (SAA), secretory phospholipase A2 IIA (SPLA2), E-selectin, vascular cellular adhesion molecule (VCAM)-1, and intercellular adhesion molecule (CAM)-1 were determined by commercial enzyme-linked immunosorbent assay kits at the same visits. RESULTS IMT and the augmentation index increased similarly in both treatment groups during the study. Plasma levels of CRP, IL-6, SPLA2, SAA, VCAM-1, ICAM-1, and E-selectin remained unchanged in both groups. CONCLUSIONS Fenofibrate treatment was not associated with beneficial changes in IMT, augmentation index, or biomarkers of inflammation and endothelial function. (Fenofibrate Intervention and Event Lowering in Diabetes; NCT00132886).

Increased augmentation of central blood pressure is associated with increases in carotid intima–media thickness in type 2 diabetic patients

Aims/hypothesisType 2 diabetes is associated with a two- to seven-fold increase in cardiovascular morbidity and mortality. The aim of this study was to determine the relationships between intima–media thickness (IMT), an established marker of atherosclerosis, large artery function and other determinants of cardiovascular risk in type 2 diabetic patients.MethodsWe studied 228 type 2 diabetic patients (75 women, aged 62±2 years [mean±SEM]). Carotid IMT was bilaterally measured using ultrasound technology. Applanation tonometry and pulse wave analysis were used to measure aortic systolic and diastolic blood pressures, central pressure augmentation (AG) and the augmentation index (AIx), a measure of systemic arterial stiffness. Conventional cardiovascular risk factors (lipids, HbA1c, smoking and diabetes duration) were also assessed.ResultsWomen had higher AG and AIx (p<0.0001), despite comparable systolic BP and heart rate in women and men. In women, AG (r=0.39, p<0.001), age (r=0.32, p<0.01), brachial systolic BP (r=0.34, p<0.01) and aortic systolic BP (r=0.34, p<0.01) correlated with IMT. In men, age (r=0.41, p<0.001), diabetes duration (r=0.25, p<0.01), AG (r=0.22, p<0.01), aortic systolic BP (r=0.21, p<0.01), brachial systolic BP (r=0.21, p<0.01) and body weight (r=0.16, p<0.05) correlated with IMT. In multiple linear regression analyses, AG and aortic systolic BP, but not brachial systolic BP, were age-independent determinants of IMT in men and women. In all patients, increased AG (adjusted for sex, age and heart rate) correlated with longer duration of diabetes, urinary albumin excretion and IMT.Conclusions/interpretationMeasures of central systolic pressure correlate with carotid IMT, independently of age and other risk markers.

High Density Lipoprotein Structural Changes and Drug Response in Lipidomic Profiles following the Long-Term Fenofibrate Therapy in the FIELD Substudy

In a recent FIELD study the fenofibrate therapy surprisingly failed to achieve significant benefit over placebo in the primary endpoint of coronary heart disease events. Increased levels of atherogenic homocysteine were observed in some patients assigned to fenofibrate therapy but the molecular mechanisms behind this are poorly understood. Herein we investigated HDL lipidomic profiles associated with fenofibrate treatment and the drug-induced Hcy levels in the FIELD substudy. We found that fenofibrate leads to complex HDL compositional changes including increased apoA-II, diminishment of lysophosphatidylcholines and increase of sphingomyelins. Ethanolamine plasmalogens were diminished only in a subgroup of fenofibrate-treated patients with elevated homocysteine levels. Finally we performed molecular dynamics simulations to qualitatively reconstitute HDL particles in silico. We found that increased number of apoA-II excludes neutral lipids from HDL surface and apoA-II is more deeply buried in the lipid matrix than apoA-I. In conclusion, a detailed molecular characterization of HDL may provide surrogates for predictors of drug response and thus help identify the patients who might benefit from fenofibrate treatment.

Common ABCA1 variants, HDL levels, and cellular cholesterol efflux in subjects with familial low HDL.

HDL promotes cholesterol efflux from peripheral cells via ABCA1 in the first step of reverse cholesterol transport (RCT). We investigated whether the early steps of RCT were disturbed in subjects with familial low HDL and an increased risk for early atherosclerosis. Cholesterol efflux from monocyte-derived macrophages to lipid-free apolipoprotein A-I (apoA-I; %) was measured in 22 patients with familial low HDL without Tangier disease mutations and in 21 healthy controls. In addition, we defined the different alleles of ABCA1 using single-nucleotide polymorphism haplotypes and measured ABCA1 and ABCG1 mRNA transcript levels in cholesterol-loaded macrophages. Similar ABCA1-mediated cholesterol efflux levels were observed for macrophages derived from control subjects and from low-HDL subjects. However, when efflux of cholesterol was estimated as cholesterol efflux to apoA-I (%)/relative ABCA1 mRNA expression level, cholesterol removal was significantly (P = 0.001) lower in the low-HDL group. Cholesterol-loaded macrophages from low-HDL subjects showed significantly increased levels of ABCA1 mRNA but not of ABCG1 mRNA and were more often carriers of the rare ABCA1 alleles L158 and R219K. These results suggest that defective ABCA1 function in cholesterol-loaded macrophages is one potential contributor to the impaired RCT process and the increased coronary heart disease risk in subjects with familial low HDL.