Abstract WP219: Lipoprotein Subfractions Are Associated With Stroke Among 9,795 Patients in the Field Trial

Background: In the FIELD trial, a 5-year randomized double-blind placebo-controlled trial of fenofibrate vs. placebo in 9,795 adults with type 2 diabetes (T2D), the only standard lipid parameter correlating with microvascular (renal) events was triglycerides. Given the high prevalence of stroke among diabetic patients, we explored associations between lipoprotein subfractions and risk for stroke in the FIELD trial.

Methods: We performed ultracentrifugation using the vertical auto profile (VAP, Atherotech) on plasma (baseline and after 6 weeks of fenofibrate). Analyses were performed using Cox proportional hazards and logistic regression for new on-study events. Results were adjusted for gender and fenofibrate or placebo allocation.

Results: HDL related analytes (HDL-C, HDL3-C, apo A1, apoA2) correlated with reduced risk for all stroke. LDL and its subfractions and Lp(a)-C did not. VLDL and its subfractions, non-HDL-C, triglycerides, apo B, apo En, various ratios incorporating apo C3, and the ratios of apoB/A1 and apoB/apoA2 all correlated with increased risk for stroke.

Conclusions: VAP identifies multiple lipoprotein subclasses, apoproteins, and VAP subclass/apoprotein ratios associated with stroke. Many of these measures improved with fenofibrate therapy.

The effect of alogliptin and pioglitazone combination therapy on various aspects of β-cell function in patients with recent-onset type 2 diabetes

OBJECTIVE

Type 2 diabetes mellitus (T2DM) management requires continuous treatment intensification due to progressive decline in β-cell function in insulin resistant individuals. Initial combination therapy of a dipeptidyl peptidase (DPP)-4 inhibitor with a thiazolidinedione (TZD) may be rational. We assessed the effects of the DPP4 inhibitor alogliptin (ALO) combined with the TZD pioglitazone (PIO), vs ALO monotherapy or placebo (PBO), on β-cell function and glycemic control in T2DM.

MATERIAL AND METHODS

A 16-week, two-center, randomized, double-blind, PBO-controlled, parallel-arm intervention study in 71 patients with well-controlled T2DM (age 59.1±6.3 years; A1C 6.7±0.1%) treated with metformin, sulfonylurea, or glinide monotherapy was conducted. Patients were treated with combined ALO 25 mg and PIO 30 mg daily or ALO 25 mg daily monotherapy or PBO. Main outcome measures included change in A1C and fasting plasma glucose (FPG) from baseline to week 16. In addition, change in β-cell function parameters obtained from standardized meal tests at baseline and at week 16 was measured.

RESULTS

ALO/PIO and ALO decreased A1C from baseline by 0.9±0.1 and 0.4±0.2% respectively (both P<0.001 vs PBO). FPG was decreased to a greater extent by ALO/PIO compared with ALO monotherapy (P<0.01). ALO/PIO treatment improved β-cell glucose sensitivity (vs PBO; P<0.001) and fasting secretory tone (vs PBO; P=0.001), while ALO monotherapy did not change β-cell function parameters. All treatments were well tolerated.

CONCLUSION

Short-term treatment with ALO/PIO or ALO improved glycemic control in well-controlled T2DM patients, but only combined ALO/PIO improved β-cell function. These data support that initial combination therapy with a DPP4 inhibitor and TZD to address multiple core defects in T2DM may be a sensible approach.

Acquired liver fat is a key determinant of serum lipid alterations in healthy monozygotic twins

OBJECTIVE

The effects of acquired obesity on lipid profile and lipoprotein composition in rare BMI-discordant monozygotic (MZ) twin pairs were studied.

DESIGN AND METHODS

Abdominal fat distribution, liver fat (magnetic resonance imaging and spectroscopy), fasting serum lipid profile (ultracentrifugation, gradient gel-electrophoresis, and colorimetric enzymatic methods), and lifestyle factors (questionnaires and diaries) were assessed in 15 BMI-discordant (within-pair difference [Δ] in BMI >3 kg/m2) and nin concordant (ΔBMI <3 kg/m2) MZ twin pairs, identified from two nationwide cohorts of Finnish twins.

RESULTS

Despite a strong similarity of MZ twins in lipid parameters (intra-class correlations 0.42-0.90, P < 0.05), concentrations of apolipoprotein B (ApoB), intermediate-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein 3a% (HDL3a%), and HDL3c% were higher (P < 0.05) and those of HDL cholesterol, HDL2-C, and HDL2b% were lower (P < 0.01) in the heavier co-twins of BMI-discordant pairs. The composition of lipoprotein particles was similar in the co-twins. When BMI-discordant pairs were further divided into liver fat-discordant and concordant (based on median for Δliver fat, 2.6%), the adverse lipid profile was only seen in those heavy co-twins who also had high liver fat. Conversely, BMI-discordant pairs concordant for liver fat did not differ significantly in lipid parameters. In multivariate analyses controlling for Δsubcutaneous, Δintra-abdominal fat, sex, Δsmoking and Δphysical activity, Δliver fat was the only independent variable explaining the variation in ΔApoB, Δtotal cholesterol, and ΔLDL-C concentration.

CONCLUSIONS

Several pro-atherogenic changes in the amounts of lipids but not in the composition of lipoprotein particles were observed in acquired obesity. In particular, accumulation of liver fat was associated with lipid disturbances, independent of genetic effects.

Heritability and familiality of type 2 diabetes and related quantitative traits in the Botnia Study

AIMS/HYPOTHESIS

To study the heritability and familiality of type 2 diabetes and related quantitative traits in families from the Botnia Study in Finland.

METHODS

Heritability estimates for type 2 diabetes adjusted for sex, age and BMI are provided for different age groups of type 2 diabetes and for 34 clinical and metabolic traits in 5,810 individuals from 942 families using a variance component model (SOLAR). In addition, family means of these traits and their distribution across families are calculated.

RESULTS

The strongest heritability for type 2 diabetes was seen in patients with age at onset 35-60 years (h (2) = 0.69). However, including patients with onset up to 75 years dropped the h (2) estimates to 0.31. Among quantitative traits, the highest h (2) estimates in all individuals and in non-diabetic individuals were seen for lean body mass (h (2) = 0.53-0.65), HDL-cholesterol (0.52-0.61) and suppression of NEFA during OGTT (0.63-0.76) followed by measures of insulin secretion (insulinogenic index [IG(30)] = 0.41-0.50) and insulin action (insulin sensitivity index [ISI] = 0.37-0.40). In contrast, physical activity showed rather low heritability (0.16-0.18), whereas smoking showed strong heritability (0.57-0.59). Family means of these traits differed two- to fivefold between families belonging to the lowest and highest quartile of the trait (p < 0.00001).

CONCLUSIONS/INTERPRETATION

To detect stronger genetic effects in type 2 diabetes, it seems reasonable to restrict inclusion of patients to those with age at onset 35-60 years. Sequencing of families with extreme quantitative traits could be an important next step in the dissection of the genetics of type 2 diabetes.

Acute suppression of VLDL1 secretion rate by insulin is associated with hepatic fat content and insulin resistance

AIMS/HYPOTHESIS

Overproduction of VLDL(1) seems to be the central pathophysiological feature of the dyslipidaemia associated with type 2 diabetes. We explored the relationship between liver fat and suppression of VLDL(1) production by insulin in participants with a broad range of liver fat content.

METHODS

A multicompartmental model was used to determine the kinetic parameters of apolipoprotein B and TG in VLDL(1) and VLDL(2) after a bolus of [(2)H(3)]leucine and [(2)H(5)]glycerol during a hyperinsulinaemic-euglycaemic clamp in 20 male participants: eight with type 2 diabetes and 12 control volunteers. The participants were divided into two groups with low or high liver fat. All participants with diabetes were in the high liver-fat group.

RESULTS

The results showed a rapid drop in VLDL(1)-apolipoprotein B and -triacylglycerol secretion in participants with low liver fat during the insulin infusion. In contrast, participants with high liver fat showed no significant change in VLDL(1) secretion. The VLDL(1) suppression following insulin infusion correlated with the suppression of NEFA, and the ability of insulin to suppress the plasma NEFA was impaired in participants with high liver fat. A novel finding was an inverse response between VLDL(1) and VLDL(2) secretion in participants with low liver fat: VLDL(1) secretion decreased acutely after insulin infusion whereas VLDL(2) secretion increased.

CONCLUSIONS/INTERPRETATION

Insulin downregulates VLDL(1) secretion and increases VLDL(2) secretion in participants with low liver fat but fails to suppress VLDL(1) secretion in participants with high liver fat, resulting in overproduction of VLDL(1). Thus, liver fat is associated with lack of VLDL(1) suppression in response to insulin.

Long-term effects of fenofibrate on VLDL and HDL subspecies in participants with type 2 diabetes mellitus

AIMS/HYPOTHESIS

Low HDL-cholesterol (HDL-C) is frequently accompanied by high triacylglycerol levels in diabetic dyslipidaemia, increasing the risk of CHD. In the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study, fenofibrate treatment lowered triacylglycerol levels, but the initial 5% increase in HDL-C attenuated over 5 years. We explored the changes in VLDL and HDL subspecies during fenofibrate treatment in a statin-free FIELD cohort.

METHODS

We randomised 171 participants with type 2 diabetes mellitus, who had been recruited to the FIELD study in Helsinki, to micronised fenofibrate (200 mg/day) or placebo in double-blind study design. VLDL and HDL subspecies were separated by ultracentrifugation at baseline and at the second and fifth year. Apolipoprotein (apo)A-I and apoA-II were measured by immunoturbidometric methods and lipoprotein (Lp)A-I and LpAI-AII particles by differential immunoassay.

RESULTS

Fenofibrate reduced plasma triacylglycerol levels by 26%, resulting from a marked reduction in VLDL1 triacylglycerol (0.62 vs 0.29 mmol/l, p < 0.001). Fenofibrate caused an increase in LDL size (Delta 0.80 nm, p < 0.001). HDL-C was similar between the groups. HDL2-C was decreased by fenofibrate (-27.5% at 5th year, p < 0.001) and HDL3-C increased (13.0% at 5th year, p < 0.001). Fenofibrate had no effect on apoA-I, whereas apoA-II increased. Thus, LpA-I decreased while LpAI-AII increased. Activities of cholesteryl ester transfer protein, phospholipids transfer protein and lecithin:cholesterylacyl transferase were unchanged by fenofibrate. High homocysteine levels were associated with a slight decrease in HDL-C and apoA-I.

CONCLUSIONS/INTERPRETATION

Fenofibrate markedly reduced large VLDL particles and produced a clear shift in HDL subspecies towards smaller particles. The HDL3-C increase in conjunction with unchanged apoA-I [corrected] levels is a dilemma with regard to cardiovascular disease.

Impact of postprandial lipaemia on low-density lipoprotein (LDL) size and oxidized LDL in patients with coronary artery disease

BACKGROUND

Remnant lipoprotein particles (RLPs) and oxidative stress are components of postprandial state. We investigated the concentrations of triglyceride-rich lipoproteins (TRLs), RLPs, low-density lipoprotein (LDL) size, and oxidized LDL (oxLDL) during alimentary lipaemia, and evaluated whether changes among these variables could be associated with the severity and extent of coronary artery disease (CAD).

MATERIALS AND METHODS

Eighty men and 27 women with clinically suspected CAD underwent quantitative coronary angiography (QCA). TRLs were isolated by density gradient ultracentrifugation before and 6 h after an oral fat load. RLPs were measured by an immunoseparation method, oxLDL by ELISA, and LDL size by gradient gel electrophoresis.

RESULTS

Triglycerides, apolipoprotein (apo) B-48, and apoB-100 concentration in Swedberg flotation units (Sf) > 400 and in Sf 12-400 fractions were markedly increased at 6 h. Postprandial cholesterol content of RLPs (RLP-C) correlated with respective triglycerides in Sf > 400 (r = 0.737) and Sf 12-400 (r = 0.857), apoB-48 in Sf > 400 (r = 0.710) and Sf 12-400 (r = 0.664), apoB-100 in Sf > 400 (r = 0.812) and Sf 12-400 (r = 0.533). RLP-C correlated with oxLDL both in fasting and in fed state (r = 0.482 and r = 0.543, respectively) and inversely with LDL size (r = -0.459 and r = -0.442, respectively). (P < 0.001 for all). OxLDL was elevated postprandially (P < 0.001). In multivariate analysis, oxLDL was a determinant of severity and extent of CAD.

CONCLUSION

Postprandial state is associated with oxidative stress. The magnitude of oxLDL increases during alimentary lipaemia and is associated with coronary atherosclerosis.

Effects of long-term fenofibrate therapy on cardiovascular events in 9795 people with type 2 diabetes mellitus (the FIELD study): randomised controlled trial

BACKGROUND

Patients with type 2 diabetes mellitus are at increased risk of cardiovascular disease, partly owing to dyslipidaemia, which can be amenable to fibrate therapy. We designed the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study to assess the effect of fenofibrate on cardiovascular disease events in these patients.

METHODS

We did a multinational, randomised controlled trial with 9795 participants aged 50-75 years, with type 2 diabetes mellitus, and not taking statin therapy at study entry. After a placebo and a fenofibrate run-in phase, we randomly assigned patients (2131 with previous cardiovascular disease and 7664 without) with a total-cholesterol concentration of 3.0-6.5 mmol/L and a total-cholesterol/HDL-cholesterol ratio of 4.0 or more or plasma triglyceride of 1.0-5.0 mmol/L to micronised fenofibrate 200 mg daily (n=4895) or matching placebo (n=4900). Our primary outcome was coronary events (coronary heart disease death or non-fatal myocardial infarction); the outcome for prespecified subgroup analyses was total cardiovascular events (the composite of cardiovascular death, myocardial infarction, stroke, and coronary and carotid revascularisation). Analysis was by intention to treat. The study was prospectively registered (number ISRCTN 64783481).

FINDINGS

Vital status was confirmed on all but 22 patients. Averaged over the 5 years' study duration, similar proportions in each group discontinued study medication (10% placebo vs 11% fenofibrate) and more patients allocated placebo (17%) than fenofibrate (8%; p<0.0001) commenced other lipid treatments, predominantly statins. 5.9% (n=288) of patients on placebo and 5.2% (n=256) of those on fenofibrate had a coronary event (relative reduction of 11%; hazard ratio [HR] 0.89, 95% CI 0.75-1.05; p=0.16). This finding corresponds to a significant 24% reduction in non-fatal myocardial infarction (0.76, 0.62-0.94; p=0.010) and a non-significant increase in coronary heart disease mortality (1.19, 0.90-1.57; p=0.22). Total cardiovascular disease events were significantly reduced from 13.9% to 12.5% (0.89, 0.80-0.99; p=0.035). This finding included a 21% reduction in coronary revascularisation (0.79, 0.68-0.93; p=0.003). Total mortality was 6.6% in the placebo group and 7.3% in the fenofibrate group (p=0.18). Fenofibrate was associated with less albuminuria progression (p=0.002), and less retinopathy needing laser treatment (5.2%vs 3.6%, p=0.0003). There was a slight increase in pancreatitis (0.5%vs 0.8%, p=0.031) and pulmonary embolism (0.7%vs 1.1%, p=0.022), but no other significant adverse effects.

INTERPRETATION

Fenofibrate did not significantly reduce the risk of the primary outcome of coronary events. It did reduce total cardiovascular events, mainly due to fewer non-fatal myocardial infarctions and revascularisations. The higher rate of starting statin therapy in patients allocated placebo might have masked a moderately larger treatment benefit.

Study of agreement between LDL size as measured by nuclear magnetic resonance and gradient gel electrophoresis

LDL particle size can be measured by gradient gel electrophoresis (GGE) and NMR. The agreement between the two methods has not been extensively evaluated. Therefore, we measured LDL size by NMR and GGE in 324 individuals (152 with type 1 diabetes and 172 controls). The Spearman correlation between both methods was 0.39 [95% confidence interval (CI) = 0.29, 0.48]. The average difference was 5.38 nm (NMR being smaller), but it increased with increasing LDL size. Less than 50% of people classified as pattern B on GGE were classified as pattern B on NMR (kappa = 0.31; 95% CI = 0.17, 0.45). Agreement was lower for diabetic subjects compared with controls, for women compared with men, and for subjects with triglycerides less than 1.30 mmol/l compared with subjects with triglycerides greater than 1.30 mmol/l. External validation showed that cholesteryl ester transfer rate was related to LDL size on GGE in all subgroups and to LDL size on NMR only in men and nondiabetic subjects. Our findings show that agreement between NMR- and GGE-based LDL size is far from perfect and is not consistent across subgroups of patients. In particular, the two methods should not be assumed to be interchangeable in women and diabetic subjects. Whether NMR or GGE predicts cardiovascular disease risk better has not yet been evaluated.

Associations between HDL oxidation and paraoxonase-1 and paraoxonase-1 gene polymorphisms in families affected by familial combined hyperlipidemia

BACKGROUND AND AIM

It has been shown in vitro that the HDL-bound enzyme paraoxonase-1 (PON1) protects LDL against oxidation, and PON1 and PON1 gene polymorphisms may affect the oxidation of HDL particles. The aim of this study was to investigate the associations between in vitro HDL oxidation parameters, endogenous PON1 and PON1 genotypes in families affected by asymptomatic FCHL.

METHODS AND RESULTS

Serum arylesterase (ARE) and PON1 activities, PON1 mass, PON1 genotypes and the kinetics of CuSO4-induced HDL oxidation in vitro were measured in 150 members of FCHL families free of clinical CAD. At univariate analysis, log PON1/apoA-I and the PON1 mass/apoA-I ratio significantly correlated with lag time, maximum diene formation and the propagation rate. The oxidation parameters also correlated with PON1 genotypes. Multivariate analysis showed that the associations between PON1 mass/unit apoA-I and the oxidation parameters were independent of the other variables. The lag time of HDL oxidation was also associated with the PON1 genotype 192QR.

CONCLUSIONS

Endogenous PON1 may have protective effects on the different stages of HDL oxidation in the members of families affected by FCHL. This protective effect is independent of other biochemical factors, but may be influenced by the PON1 gene polymorphism. The endogenous PON1 content of HDL seems to be an important determinant of the anti-atherogenicity of this lipoprotein.

Controlling lipid levels in diabetes

Coronary heart disease (CHD) is associated with a 2- to 4-times greater risk of morbidity and mortality in patients with type 2 diabetes than in non-diabetic individuals. Dyslipidaemia is an important CHD risk factor in diabetic patients. The key atherogenic features of diabetic dyslipidaemia are elevated levels of serum triglycerides, low levels of high density lipoprotein (HDL) cholesterol, and the preponderance of small, dense low density lipoprotein (LDL). As a result, treatment guidelines for diabetic dyslipidaemia recommend elevated LDL cholesterol and triglyceride levels and low HDL cholesterol levels as targets of therapy. Unfortunately, however, these lipid abnormalities often persist despite best efforts to control hyperglycaemia, improve diet, and increase physical exercise, and therefore demand specific therapeutic intervention. Statins are the first choice for LDL cholesterol lowering as they are effective and well tolerated, and do not have adverse effects on glycaemic control. Furthermore, recent evidence suggests that statins may also be employed to treat moderately elevated levels of triglycerides. An increasing number of primary and secondary prevention trials have shown that lipid-lowering therapy with statins can significantly reduce the risk of CHD events in patients with diabetic dyslipidaemia.

Lipoprotein subclasses and particle sizes and their relationship with coronary artery calcification in men and women with and without type 1 diabetes

Type 1 diabetes is associated with increased coronary atherosclerosis, especially in women, even though such patients often have an apparently normal lipid profile. We examined whether lipoprotein particle sizes and subclasses differed between type 1 diabetic subjects (n = 194, age 30-55 years) and age- and sex-matched control subjects (n = 195). We examined whether any abnormalities were of similar magnitude in men and women. The relationship of particle size to electron beam computer tomography-defined coronary artery calcification, a measure of atherosclerosis, was also examined. Proton nuclear magnetic resonance (NMR) spectroscopy was used to quantify VLDL, LDL, and HDL subclass levels and average particle size on fasting samples. LDL size and subclass were similar in diabetic and nondiabetic men. In contrast, in women diabetes was associated with less large and more small LDL and a reduced LDL size (mean difference 0.2 nm; P = 0.0009). This greater effect of diabetes on LDL size in women compared with men was significant (P = 0.007). Diabetes was associated with more large and less small HDL and, to a similar degree in both sexes, a higher HDL size (difference of 0.4 nm in men and 0.3 nm in women; both P < 0.0001). There were no definitive abnormalities in VLDL size. In nondiabetic subjects, lower average HDL particle size, lower LDL size, and higher VLDL size were significantly associated with coronary calcification (P = 0.001, 0.02, and 0.04, respectively). Thus the HDL size differences with diabetes would be expected to be antiatherogenic and the LDL size differences pro-atherogenic. However, there was no clear relationship between particle size and calcification in diabetic subjects. We conclude that in the general population NMR spectroscopy-derived particle size reveals important information about the atherogenicity of lipoprotein profile. Type 1 diabetes is associated with differences in NMR-derived particle size, but their pathogenic significance is unclear.

Pathogenesis of dyslipidemia in type 2 diabetes

The recognition that hypertriglyceridemia is associated with multiple alterations of other lipoproteins that are potentially atherogenic has expanded the picture of diabetic dyslipidemia. Elevation of large VLDL1 particles initiate a sequence of events that results in generation of atherogenic lipoproteins including remnants and small dense LDL. This abnormality is also associated with the lowering of HDL cholesterol. The clinical implication is that the concentration of plasma triglycerides should be maintained as low as possible to avoid these deleterious consequences of hypertriglyceridemia.

Differing associations of lipid and lipoprotein disturbances with the macrovascular and microvascular complications of type 1 diabetes

OBJECTIVE

Cardiovascular disease (CVD) is increased in patients with type 1 diabetes, but lipid and lipoprotein patterns remain favorable. In contrast, nephropathy is associated with an adverse distribution. We compared the associations and predictive power of lipid and lipoprotein disturbances with these complications.

RESEARCH DESIGN AND METHODS

A nested case-control study from the EURODIAB cohort of 140 case subjects with evidence of at least one complication and 84 control subjects with no complications were analyzed. Conventional and unconventional lipid and lipoprotein fractions, including apolipoprotein (apo)-A1, lipoprotein (Lp)-A1, LpA1/A2, apoB, and LDL particle size were measured centrally.

RESULTS

CVD was only associated with increased LDL cholesterol (3.6 vs. 3.0 mmol/l, P = 0.02). In contrast, albuminuria was associated with elevated cholesterol, triglyceride, LDL, and apoB and with diminished LDL particle size. No disturbances in HDL and related lipoproteins were noted. In normoalbuminuric patients, CVD was not associated with any significant changes in lipids. CVD in macroalbuminuric patients was associated with increased triglyceride level (2.37 vs. 1.07 mmol/l, P = 0.001; P = 0.02 for CVD/albuminuria interaction) and LDL cholesterol (5.4 vs. 3.3 mmol/l, P = 0.005; P = 0.004 for interaction). Independent associations were observed for total cholesterol and for LDL particle size and albuminuria.

CONCLUSIONS

Abnormalities in lipid and lipoprotein disturbances are more closely related to albuminuria than to CVD in patients with type 1 diabetes. Measurement of conventional parameters provide sufficient risk information. ApoB and LDL particle size offer limited extra information. HDL metabolism remains undisturbed in the presence of complications. These changes reflect associations with glycemic control, which is the key to understanding lipid and lipoprotein disturbances.

The metabolic syndrome influences the risk of chronic complications in patients with type II diabetes

AIMS/HYPOTHESIS

We examined features of the metabolic syndrome to see if they modified the risk of chronic diabetic complications in patients with Type II (non-insulin-dependent) diabetes mellitus.

METHODS

A total of 85 randomly selected patients with the metabolic syndrome (WHO definition) were compared with 85 Type II diabetic patients matched for age, sex, duration of diabetes, glycaemic control and without the syndrome to assess the microvascular and macrovascular complications.

RESULTS

The patients with the metabolic syndrome had a higher prevalence of cardiovascular disease (52 vs 21%, p < 0.001), microalbuminuria or macroalbuminuria (23 vs 7%, p = 0.003) and distal neuropathy (16 vs 6%, p = 0.048) than patients without the syndrome. The patients with the metabolic syndrome had smaller LDL particle size (25.4+/-1.4 vs 26.4+/-1.1 nm; p < 0.001), which correlated with the ratio of serum triglycerides to HDL cholesterol (r = -0.64, p < 0.001). In a multiple logistic regression analysis the metabolic syndrome was associated with coronary heart disease (RR 3.84, p < 0.001) and microalbuminuria (RR 3.99, p = 0.01). Small LDL particle size was independently associated with neuropathy (RR 0.58; p = 0.04), whereas a high HbA1c was related to neuropathy (RR 1.69, p = 0.04), retinopathy (RR 1.53, p = 0.002) and microalbuminuria (RR 1.54, p = 0.01).

CONCLUSION/INTERPRETATION

Although chronic hyperglycaemia is the main predictor of microvascular complications in patients with Type II diabetes, this risk is modified by some of the components of the metabolic syndrome.

Serum C3 but not plasma acylation-stimulating protein is elevated in Finnish patients with familial combined hyperlipidemia

A trapping defect of fatty acids due to impaired function of acylation-stimulating protein (ASP) has been suggested as one mechanism underlying the metabolic abnormalities in familial combined hyperlipidemia (FCHL). The study aimed at defining the role of ASP and complement C3 in 35 Finnish FCHL families. There was no difference in plasma ASP levels between the 66 hypertriglyceridemic FCHL patients and their 84 normotriglyceridemic relatives. No response in plasma ASP could be observed after a fatty meal in 10 FCHL patients or in 10 control subjects. In familial correlation analyses, C3 exhibited a significant sibling-sibling correlation. The FCHL patients had higher serum C3 levels than their unaffected relatives (P<0.001). Furthermore, serum C3 levels correlated significantly with several lipid parameters. The correlations between ASP and lipid variables were weaker than those of C3. These analyses suggest that common genes might contribute to the regulation of serum C3, triglycerides, HDL-C, free fatty acids, and insulin. The present data do not support the hypothesis that defects of the ASP pathway are reflected in plasma lipoproteins or in impaired plasma lipid clearance postprandially.

Remnant-like lipoprotein particle cholesterol concentration and progression of coronary and vein-graft atherosclerosis in response to gemfibrozil treatment

Remnant lipoproteins such as chylomicron and very low density lipoprotein (VLDL) remnants have been implicated in the progression of coronary atherosclerosis. Recently, a novel method for the determination of the remnant-like lipoprotein particle cholesterol (RLP-C) concentration was developed based on immunoaffinity-separation of plasma. The compositional characteristics of RLP are strikingly similar to those of postprandially modified VLDL. In addition, the method also detects chylomicron remnants. We investigated the relationship between the plasma RLP-C concentration and the angiographic outcome of the 2-year, randomised, placebo-controlled Lipid Coronary Angiography Trial (LOCAT), which used gemfibrozil as lipid lowering agent. The RLP-C response to gemfibrozil treatment has not been described before. Gemfibrozil reduced the median RLP-C concentration by 34%. The on-treatment RLP-C concentration was significantly associated with the progression of the minimum lumen diameter (MLD) (P<0.004). The plasma levels of RLP-C as well as the change in response to treatment was closely associated with plasma triglycerides and the association between on-treatment RLP-C concentration and progression of MLD was not independent of plasma triglycerides. A significant relation was seen between RLP-C and the occurrence of new lesions in vein grafts. Subjects with one new lesion had an approximately 25% higher on-treatment RLP-C concentration and the four patients showing two new lesions had a 100% higher RLP-C concentration than patients without vein graft stenosis. A total of 19 out of 23 subjects having one new lesion, and all four patients showing two new lesions, were assigned to the placebo group. We conclude that the RLP-C concentration, which is likely to reflect the plasma cholesterol contained in postprandially modified VLDL and chylomicron remnants, is strongly associated with angiographically verified progression of focal coronary atherosclerosis, and that lowering of RLPs prevents vein graft stenosis.

Metabolic effects of metformin in patients with impaired glucose tolerance

AIMS

To assess the effect of metformin on insulin sensitivity, glucose tolerance and components of the metabolic syndrome in patients with impaired glucose tolerance (IGT).

METHODS

Forty first-degree relatives of patients with Type 2 diabetes fulfilling WHO criteria for IGT and participating in the Botnia study in Finland were randomized to treatment with either metformin 500 mg b.i.d. or placebo for 6 months. An oral glucose tolerance test (OGTT) and a euglycaemic hyperinsulinaemic clamp in combination with indirect calorimetry was performed at 0 and 6 months. The patients were followed after stopping treatment for another 6 months in an open trial and a repeat OGTT was performed at 12 months.

RESULTS

Metformin treatment resulted in a 20% improvement in insulin-stimulated glucose metabolism (from 28.7 +/- 13 to 34.4 +/- 10.7 micromol/kg fat-free mass (FFM)/min) compared with placebo (P = 0.01), which was primarily due to an increase in glucose oxidation (from 16.6 +/- 3.6 to 19.1 +/- 4.4 micromol/kg FFM; P = 0.03) These changes were associated with a minimal improvement in glucose tolerance, which was maintained after 12 months.

CONCLUSIONS

Metformin improves insulin sensitivity in subjects with IGT primarily by reversal of the glucose fatty acid cycle. Obviously large multicentre studies are needed to establish whether these effects are sufficient to prevent progression to manifest Type 2 diabetes and associated cardiovascular morbidity and mortality. Diabet. Med. 18, 578-583 (2001)

Effects of oral and transdermal estrogen replacement therapy on markers of coagulation, fibrinolysis, inflammation and serum lipids and lipoproteins in postmenopausal women

We compared the effects of oral estradiol (2 mg), transdermal estradiol (50 microg), and placebo on measures of coagulation, fibrinolysis, inflammation and serum lipids and lipoproteins in 27 postmenopausal women at baseline and after 2 and 12 weeks of treatment. Oral and transdermal estradiol induced similar increases in serum free estradiol concentrations. Oral therapy increased the plasma concentrations of factor VII antigen (FVIIag) and activated factor VII (FVIIa), and the plasma concentration of the prothrombin activation marker prothrombin fragment 1+2 (F1+2). Oral but not transdermal estradiol therapy significantly lowered plasma plasminogen activator inhibitor-1 (PAI-1) antigen and tissue-type plasminogen activator (tPA) antigen concentrations and PAI-1 activity, and increased D-dimer concentrations, suggesting increased fibrinolysis. The concentration of soluble E-selectin decreased and serum C-reactive protein (CRP) increased significantly in the oral but not in the transdermal or placebo groups. In the oral but not in the transdermal or placebo estradiol groups low-density-lipoprotein (LDL) cholesterol, apolipoprotein B and lipoprotein (a) concentrations decreased while high-density-lipoprotein (HDL) cholesterol, apolipoprotein AI and apolipoprotein All concentrations increased significantly. LDL particle size remained unchanged. In summary, oral estradiol increased markers of fibrinolytic activity, decreased serum soluble E-selectin levels and induced potentially antiatherogenic changes in lipids and lipoproteins. In contrast to these beneficial effects, oral estradiol changed markers of coagulation towards hypercoagulability, and increased serum CRP concentrations. Transdermal estradiol or placebo had no effects on any of these parameters. These data demonstrate that oral estradiol does not have uniformly beneficial effects on cardiovascular risk markers and that the oral route of estradiol administration rather than the circulating free estradiol concentration is critical for any changes to be observed.

Cardiovascular morbidity and mortality associated with the metabolic syndrome

OBJECTIVE

To estimate the prevalence of and the cardiovascular risk associated with the metabolic syndrome using the new definition proposed by the World Health Organization

RESEARCH DESIGN AND METHODS

A total of 4,483 subjects aged 35-70 years participating in a large family study of type 2 diabetes in Finland and Sweden (the Botnia study) were included in the analysis of cardiovascular risk associated with the metabolic syndrome. In subjects who had type 2 diabetes (n = 1,697), impaired fasting glucose (IFG)/impaired glucose tolerance (IGT) (n = 798) or insulin-resistance with normal glucose tolerance (NGT) (n = 1,988), the metabolic syndrome was defined as presence of at least two of the following risk factors: obesity, hypertension, dyslipidemia, or microalbuminuria. Cardiovascular mortality was assessed in 3,606 subjects with a median follow-up of 6.9 years.

RESULTS

In women and men, respectively, the metabolic syndrome was seen in 10 and 15% of subjects with NGT, 42 and 64% of those with IFG/IGT, and 78 and 84% of those with type 2 diabetes. The risk for coronary heart disease and stroke was increased threefold in subjects with the syndrome (P < 0.001). Cardiovascular mortality was markedly increased in subjects with the metabolic syndrome (12.0 vs. 2.2%, P < 0.001). Of the individual components of the metabolic syndrome, microalbuminuria conferred the strongest risk of cardiovascular death (RR 2.80; P = 0.002).

CONCLUSIONS

The WHO definition of the metabolic syndrome identifies subjects with increased cardiovascular morbidity and mortality and offers a tool for comparison of results from diferent studies.

Cholesterol efflux capacity in vitro predicts the severity and extent of coronary artery disease in patients with and without type 2 diabetes

OBJECTIVE

To investigate the relation between severity and extent of coronary artery disease (CAD) and in vitro cholesterol efflux capacity.

DESIGN

This study consisted of 46 type 2 diabetic, and 42 nondiabetic men undergoing coronary angiography. Quantitative coronary angiography was used to estimate the severity, extent, and overall "atheroma burden" of CAD. The capacity of patient plasma to induce cholesterol efflux from cultured Fu5AH rat hepatoma cells was measured in vitro.

RESULTS

In the combined study population (n = 88), there was a significant inverse correlation between efflux and global atheroma burden (r = -0.23, p < 0.05). In the diabetic group, the global atheroma burden index was independently associated both with cholesterol efflux and with LpA-I levels. However, in the nondiabetic CAD group this association was lost when efflux and LpA-I levels were included in the same model.

CONCLUSION

The present study demonstrated that efflux capacity was inversely associated with the severity and extent of CAD. In the diabetic group this association was independent of LpA-I levels, suggesting impaired antiatherogenic potential of these particles in type 2 diabetic patients.

Determinants of the severity and extent of coronary artery disease in patients with type-2 diabetes and in nondiabetic subjects

BACKGROUND

Factors predicting the anatomic distribution and the severity and extent of coronary atherosclerosis in patients with clinically manifest coronary artery disease (CAD) for type-2 diabetic patients could be different than those for nondiabetic patients.

OBJECTIVE

To study the determinants of severity and extent of CAD in consecutive patients with type 2 diabetes mellitus, compared with those for matched nondiabetic patients, undergoing clinically indicated coronary angiography.

METHODS

Coronary angiograms of 48 men and seven women with type-2 diabetes and an equal number of nondiabetic subjects were analyzed quantitatively. Scores reflecting severity and extent of CAD were compared with potential risk factors using univariate correlation analyses and multivariate regression models.

RESULTS

For the diabetics, a global coronary atheroma burden index was independently and directly related to age (P = 0.022) and to level of intermediate-density lipoprotein cholesterol (P = 0.055), and inversely to level of particles of a subtype of high-density lipoprotein (P = 0.022). Several angiographic indexes were related to the duration of diabetes and control of glycemia. For the nondiabetic group, global atheroma burden was independently related to age (P = 0.028), a history of hypertension (P = 0.028), and concentration of low-density lipoprotein (P = 0.013), and inversely to level of apolipoprotein A-I (P = 0.008). The duration of coronary disease and a history of smoking were also predictive of severe coronary atherosclerosis among nondiabetic patients.

CONCLUSIONS

Classical risk factors are strong predictors of the severity and extent of coronary atherosclerosis in nondiabetic patients, but the most important determinants for type-2 diabetic patients are levels of triglyceride-rich lipoproteins and apolipoprotein A-I-containing particles of high-density lipoprotein, and factors directly related to diabetes.

Reduced hormone-sensitive lipase activity is not a major metabolic defect in Finnish FCHL families

The pathogenetic mechanisms behind familial combined hyperlipidemia (FCHL) are unknown. However, exaggerated postprandial lipemia and excessive serum free fatty acid (FFA) concentrations have drawn attention to altered lipid storage and lipolysis in peripheral adipose tissue. Hormone-sensitive lipase (HSL) is the enzyme responsible for intracellular lipolysis in adipocytes and a decrease of adipocyte HSL activity has been demonstrated in Swedish FCHL subjects. The aim of the study was to investigate if adipose tissue HSL activity had any effect on lipid phenotype and if low HSL activity and FCHL were linked in Finnish FCHL families. A total of 48 family members from 13 well-characterized Finnish FCHL families and 12 unrelated spouses participated in the study. FCHL patients with different lipid phenotypes (IIA, IIB, IV) did not differ in adipose tissue HSL activity from each other or from the 12 normolipidemic spouses (P = 0.752). In parametric linkage analysis using an affecteds-only strategy the low adipose tissue HSL activity was not significantly linked with FCHL phenotype. However, we found a significant sibling-sibling correlation for the HSL trait (0.51, P < 0.01). Thus, a modifying or interacting role of HSL in the pathogenesis of FCHL could not be excluded.

Differential effects of oral and transdermal estrogen replacement therapy on endothelial function in postmenopausal women

BACKGROUND

We determined whether the vascular effects of estradiol depend on the route of administration by comparing the effects of oral estradiol and transdermal placebo, transdermal estradiol and oral placebo, and transdermal placebo and oral placebo on in vivo endothelial function in 27 postmenopausal women.

METHODS AND RESULTS

Endothelial function was assessed from blood flow responses to intrabrachial artery infusions of endothelium-dependent (7.5 and 15 microgram/min acetylcholine) and endothelium-independent (3 and 10 microgram/min of sodium nitroprusside) vasodilators at 0, 2, and 12 weeks. In the oral estradiol group, the increase in flow above basal during infusion of the low dose of acetylcholine at 0, 2, and 12 weeks averaged 6.0+/-0.8, 6.9+/-0.8, and 11.3+/-1.2 (P<0.01 versus 0 and 2 weeks) mL. dL(-1). min(-1) at 0, 2, and 12 weeks. The percentage increases versus 0 weeks averaged 21+/-14% at 2 and 120+/-34% at 12 weeks. During the high-dose acetylcholine infusion, the increase in flow above basal averaged 8.6+/-1.3, 10.2+/-1.5, and 15.1+/-1.8 (P<0.05 versus 0 weeks) mL. dL(-1). min(-1), respectively. The percentage increases versus 0 weeks averaged 22+/-10% at 2 weeks and 119+/-46% at 12 weeks. In the oral estradiol group, endothelium-independent vasodilatation also improved significantly, but less markedly than endothelium-dependent responses. In the transdermal and placebo groups, all vascular responses remained unchanged. Oral but not transdermal estradiol also induced significant decreases in LDL cholesterol and Lp(a) concentrations and an increase in HDL cholesterol within 2 weeks.

CONCLUSIONS

We conclude that oral but not transdermal estradiol induces potentially antiatherogenic changes in in vivo endothelium-dependent vasodilatation and lipid concentrations.

Angiographic severity and extent of coronary artery disease in patients with type 1 diabetes mellitus

Studies of the characteristics of coronary artery disease (CAD) in diabetic patients have shown conflicting results. Only 2 studies exploring the severity of CAD, specifically in type 1 diabetes, have been published, and neither of them has used computer-aided quantitative coronary angiography. This retrospective study comprised 64 (24 women and 40 men) type 1 diabetic patients and nondiabetic control subjects. To estimate the severity, extent, and overall "atheroma burden" of CAD, we used quantitative coronary angiographic-based segmental analysis of coronary angiograms. Type 1 diabetic patients had greater global severity (p < 0.001), global extent (p < 0.001), and global atheroma burden (p < 0.001) indexes than nondiabetic control subjects. Quantitative coronary angiographic-derived indexes of CAD were, on average, 1.4- to 4.3-fold higher in diabetic than in nondiabetic patients. These differences were particularly marked in women. We found that type 1 diabetic patients with a clinical indication for coronary angiography, especially women, have more severe, extensive, and distal type of CAD than individually matched nondiabetic control patients. Our findings, including a loss of sex difference for CAD among type 1 diabetic patients and a marked impact of type 1 diabetes in women, are not explained by established risk factors.

Differences in HDL-cholesterol:apoA-I + apoA-II ratio and apoE phenotype with albuminuric status in Type I diabetic patients

AIMS/HYPOTHESIS

To examine whether the HDL-cholesterol:apoA-I + apoA-II ratio and the epsilon2 allele are related to albuminuria at baseline and whether they are risk factors for progression of albuminuria in a cohort study of patients with Type I (insulin-dependent) diabetes mellitus.

METHODS

At baseline, the study cohort comprised 617 patients, aged 15-60 years, from seven European diabetic centres of the EURODIAB study. Albumin excretion rate, measured in a central laboratory, was categorised as normoalbuminuria at 20 microg/min or less, microalbuminuria between 20 and 200 microg/min or macroalbuminuria at 200 microg/min or over. Of the 250 patients who were normoalbuminuric at baseline and had follow-up albuminuria measurements, 34 patients were defined as early progressors.

RESULTS

At baseline, the mean HDL-cholesterol:apoA-I + apoA-II ratio was lower in macroalbuminuric patients (0.79, 95 % CI:0.74-0.83) compared with normoalbuminuric (0.88, 95 % CI:0.87-0.90) patients (p = 0.0002, adjusted for age and sex). At follow-up, 34 patients who progressed from normoalbuminuria to microalbuminuria or macroalbuminuria also had a slightly lower baseline ratio (0.85, 95% CI:0.80-0.89) than those 216 who remained normoalbuminuric (0.89, 95 % CI:0.87-0.92) (adjusted p = 0.08). Neither of these relations were independent of LDL-cholesterol or fasting triglyceride. There was no association of the epsilon2 allele with albuminuria either at baseline (OR = 1.4, 95% CI:0.7-2.8) or with progression of albuminuria (OR = 0.4, 95 % CI:0.1-3.5).

CONCLUSION/INTERPRETATION

There is an inverse relation of HDL-cholesterol:apoA-I + apoA-II ratio with albuminuria at baseline. This lower ratio in microalbuminuric or macroalbuminuric patients could contribute to the increased risk of cardiovascular disease associated with nephropathy. There is weak evidence that HDL-composition is a risk factor for progression of albuminuria and no association of the epsilon2 allele with diabetic nephropathy.

Endothelial dysfunction in men with small LDL particles

BACKGROUND

It is unknown whether LDL particle size is, independent of other lipids and lipoproteins, associated with endothelial dysfunction in vivo.

METHODS AND RESULTS

We determined in vivo endothelial function in 34 healthy men by measuring forearm blood flow responses to intrabrachial artery infusions of acetylcholine (ACh, an endothelium-dependent vasodilator) and sodium nitroprusside (an endothelium-independent vasodilator). LDL peak particle size was measured with gradient gel electrophoresis. Men with small LDL particles (LDL diameter </=25.5 nm, n=10) had a 39% lower blood flow response to ACh than men with large LDL particles (LDL diameter >25. 5 nm, n=24, blood flow 6.9+/-3.6 versus 11.4+/-5.1 mL/dL. min, P=0. 006). The groups had comparable LDL cholesterol concentrations (3. 9+/-0.6 versus 3.7+/-1.0 mmol/L, men with small versus large LDL particles), blood pressure, glucose concentrations, and body mass indexes. LDL size (r=0.45, P=0.01) but not HDL cholesterol (r=0.31, P=0.09) or triglycerides (r=-0.19, P=0.30) was significantly correlated with endothelium-dependent vasodilation. Serum triglyceride concentrations and LDL size were inversely correlated (r=-0.44, P=0.01). In multivariate regression analysis, LDL size was the only significant determinant of the ACh-induced increase in blood flow. Sodium nitroprusside-stimulated endothelium-independent vasodilation was similar in both groups.

CONCLUSIONS

Small LDL particles are associated with impaired in vivo endothelial function independent of HDL and LDL cholesterol and triglyceride concentrations. LDL size may therefore mediate adverse effects of hypertriglyceridemia on vascular function.

Interaction between the Asn291Ser variant of the LPL gene and insulin resistance on dyslipidaemia in high risk individuals for Type 2 diabetes mellitus

AIMS

Lipoprotein lipase (LPL) is a major regulator of triglyceride clearance. A genetic variant of the LPL gene on chromosome 8p22, Asn291Ser, has previously been associated with dyslipidaemia and an increased frequency of cardiovascular disease as well as familial disorders of lipoprotein metabolism. The aim of this study was to test whether the phenotypic expression of the LPL Asn291Ser variant is dependent upon glucose tolerance and insulin resistance. Therefore, the Asn291Ser variant was examined in 192 patients with Type 2 diabetes, 278 subjects with normal glucose tolerance who are first degree relatives of patients with Type 2 diabetes and 226 healthy control spouses without family history of diabetes.

METHODS

The subjects were genotyped with an allele-specific mini-sequencing method. Insulin resistance was estimated using the homeostasis model assessment (HOMA) index.

RESULTS

The frequency of the Asn/Ser genotype was significantly increased in normoglycaemic subjects with hypertriglyceridaemia (> 1.7 mmol/1), and was associated with dyslipidaemia and increased systolic blood pressure. There was a significant interaction between Asn291Ser and insulin resistance in normoglycaemic subjects, indicating that dyslipidaemia is more severe in Asn/ Ser carriers with reduced insulin sensitivity. The frequency of the Asn/Ser genotype was not increased in diabetic subjects with hypertriglyceridaemia, but was associated with increased systolic blood pressure.

CONCLUSIONS

The Asn/Ser genotype of the LPL gene is associated with dyslipidaemia in normoglycaemic subjects, and the dyslipidaemic phenotype is more severe in insulin-resistant subjects. This association is not seen in diabetic subjects.

G-250A substitution in promoter of hepatic lipase gene is associated with dyslipidemia and insulin resistance in healthy control subjects and in members of families with familial combined hyperlipidemia

Low activity of hepatic lipase (HL) has been associated with high levels of triglycerides and high density lipoproteins, but the association of the HL promoter variants with insulin sensitivity has not been investigated. Therefore, in this study, the relationship of the G-250A promoter variant of the HL gene to the rates of insulin-stimulated glucose uptake measured by the hyperinsulinemic euglycemic clamp was investigated in 110 control subjects (82 men and 28 women, aged 50.7+/-7.6 [mean+/-SD] years, body mass index 26. 1+/-3.6 kg/m(2)) and in 105 first-degree relatives (65 men and 40 women, aged 47.8+/-16.0 years, body mass index 26.9+/-5.3 kg/m(2)) of 34 families with familial combined hyperlipidemia (FCHL). The A-250 allele of the HL promoter was associated with low rates of insulin-stimulated whole-body nonoxidative glucose disposal in control subjects (41.1+/-12.7 micromol. kg(-1). min(-1) in subjects with the G-250G genotype, 36.9+/-13.1 micromol. kg(-1). min(-1) in subjects with the G-250A genotype, and 29.9+/-13.5 micromol. kg(-1). min(-1) in subjects with the A-250A genotype; P=0.012 adjusted for age and sex) and with low rates of insulin-stimulated whole-body glucose oxidation in FCHL family members (16.7+/-4.2 versus 15.0+/-4. 4 versus 14.1+/-4.4 micromol. kg(-1). min(-1), P=0.024). In addition, the A-250 allele was associated with high levels of fasting insulin (P=0.047), very low density lipoprotein cholesterol (P=0.007), and total (P=0.009) and very low density lipoprotein (P=0.005) triglycerides in control subjects and with high levels of low density lipoprotein triglycerides (P=0.001) in FCHL family members (n=340). We conclude that the G-250A promoter variant of the HL gene is associated with dyslipidemia and insulin resistance. Mechanisms via which this polymorphism could affect insulin sensitivity remain to be elucidated.

Insulin secretion and insulin sensitivity in relation to glucose tolerance: lessons from the Botnia Study

Recently, a new stage in glucose tolerance, impaired fasting glucose (IFG) (fasting plasma glucose level of 6.1-6.9 mmol/l), was introduced in addition to impaired glucose tolerance (IGT) (2-h glucose level of 7.8-11.0 mmol/l). It is not clear whether IFG and IGT differ with respect to insulin secretion or sensitivity. To address this question, we estimated insulin secretion (by measuring both insulin levels and the ratio of insulin-to-glucose levels in 30-min intervals) and insulin sensitivity (by using the homeostasis model assessment [HOMA] index) from an oral glucose tolerance test (OGTT) in 5,396 individuals from the Botnia Study who had varying degrees of glucose tolerance. There was poor concordance between IFG and IGT: only 36% (303 of 840) of the subjects with IFG had IGT, whereas 62% (493 of 796) of the subjects with IGT did not have IFG. Compared with subjects with normal glucose tolerance (NGT), subjects with IFG were more insulin resistant (HOMA-insulin resistance [IR] values 2.64 +/- 0.08 vs. 1.73 +/- 0.03, P < 0.0005), had greater insulin responses during an OGTT (P = 0.0001), had higher waist-to-hip ratios (P < 0.005), had higher triglyceride and total cholesterol concentrations (P < 0.0005), and had lower HDL cholesterol concentrations (P = 0.0001). Compared with subjects with IFG, subjects with IGT had a lower incremental 30-min insulin-to-glucose area during an OGTT (13.8 +/- 1.7 vs. 21.7 +/- 1.7, P = 0.0008). Compared with subjects with IGT, subjects with mild diabetes (fasting plasma glucose levels <7.8 mmol/l) showed markedly impaired insulin secretion that could no longer compensate for IR and elevated glucose levels. A progressive decline in insulin sensitivity was observed when moving from NGT to IGT and to subjects with diabetes (P < 0.05 for trend), whereas insulin secretion followed an inverted U-shaped form. We conclude that IFG is characterized by basal IR and other features of the metabolic syndrome, whereas subjects with IGT have impaired insulin secretion in relation to glucose concentrations. An absolute decompensation of beta-cell function characterizes the transition from IGT to mild diabetes.

A nine-month, placebo-controlled study of the effects of growth hormone treatment on lipoproteins and LDL size in abdominally obese men

Abdominal/visceral obesity is associated with blunted growth hormone (GH) secretion and an unfavourable lipoprotein pattern. In this study, the effect of GH treatment on LDL size and on serum lipoprotein concentrations was determined in abdominally obese men. Thirty men, aged 48-66 years, with a body mass index (BMI) of 25-35 kg/m(2)and a waist:hip ratio of >0.95, received treatment with GH (9. 5 microg/kg/day) or placebo for 9 months. Serum concentrations of total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (apoB) were reduced (P<0.05, P<0.05 and P<0.001 vs placebo, respectively). Serum lipoprotein(a) [Lp(a)] concentration increased (P<0.05 vs. placebo). Mean low density lipoprotein (LDL) particle diameter was marginally increased by active treatment as compared with placebo (P =0.08). No changes were observed in the serum concentrations of high density lipoprotein-cholesterol (HDL-C), apolipoprotein A-I (apoA-I) and apolipoprotein E (apoE). In conclusion, 9 months of GH treatment in abdominally obese men beneficially reduced serum concentrations of TC, LDL-C and apoB, and marginally increased mean LDL diameter, while serum Lp(a) increased. The ultimate effect of GH therapy on the cardiovascular risk remains, however, to be determined.

Suppression of nocturnal fatty acid concentrations by bedtime carbohydrate supplement in type 2 diabetes: effects on insulin sensitivity, lipids, and glycemic control

BACKGROUND

Bedtime ingestion of slow-release carbohydrates leads to sustained nocturnal fatty acid suppression and improved glucose tolerance in type 2 diabetic patients.

OBJECTIVE

This study assessed the effects of 2 different doses of bedtime carbohydrate supplement (BCS) on morning glycemic control and glycated hemoglobin (Hb A(1c)) in type 2 diabetic patients. In addition, the effects of the high-dose BCS on insulin sensitivity and postprandial glucose and triacylglycerol concentrations were assessed.

DESIGN

Two BCS doses were studied separately in 7-wk randomized, placebo-controlled, double-blind studies with either a parallel (low-dose BCS; n = 24 patients) or crossover (high-dose BCS; n = 14 patients) design. The effects of the low and high doses (0.30 and 0.55 g uncooked cornstarch/kg body wt, respectively) were compared with those of a starch-free placebo.

RESULTS

Compared with the starch-free placebo, the high-dose BCS ( approximately 45 g) produced enhanced nocturnal glucose (P < 0.01) and insulin (P < 0.01) concentrations as well as a 32% suppression of fatty acid concentrations (P < 0.01). Moreover, glucose tolerance (P < 0.05) and C-peptide response (P < 0.05) improved after breakfast the next morning. The low-dose BCS ( approximately 25 g) improved fasting blood glucose concentrations (P < 0.05). However, there were no improvements in insulin sensitivity, postprandial triacylglycerol concentrations, or Hb A(1c) after 7 wk.

CONCLUSION

Nocturnal fatty acid suppression by BCS improved fasting and postprandial blood glucose concentrations in type 2 diabetic patients the next morning. In contrast, no improvements in insulin sensitivity, postprandial triacylglycerol concentrations, or long-term glycemic control assessed by Hb A(1c) were seen after BCS supplementation.

Consequences of a family history of type 1 and type 2 diabetes on the phenotype of patients with type 2 diabetes

OBJECTIVE

To investigate the impact of a family history of type 1 and type 2 diabetes on the phenotype of patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

In a population-based study, we compared the phenotype in 3 groups of patients with type 2 diabetes. The first group had no family history of diabetes (FH-, n = 148); the second group had a family history of type 2 diabetes only (FH+(TYPE2), n = 1,211); and the third group had a family history of both type 1 and type 2 diabetes (FH+(MIXED), n = 240). Furthermore, we studied the frequency of GAD antibodies (GADabs), HLA-DQB1 risk genotypes, and the presence of coronary heart disease (CHD) according to family history in unrelated patients with type 2 diabetes from 787 families (148 FH-, 546 FH+(TYPE2) and 93 FH+(MIXED)).

RESULTS

Patients with no family history of diabetes were older at the onset of the disease, had a better beta-cell function (P = 0.004), and had higher HDL cholesterol concentrations (P = 0.006) than patients with a family history of diabetes. Patients with a family history of only type 2 diabetes had higher BMI and fasting C-peptide concentrations (P = 0.031) but lower frequency of GADab (11 vs. 23%, P = 0.001) and DQB1 risk genotypes (37 vs. 54%, P = 0.003) compared with patients with a family history of both type 1 and type 2 diabetes. In addition, hypertension (P = 0.05) and CHD (P = 0.031) were more common in FH+(TYPE2) than in FH+(MIXED) patients. In patients <60 years old, a family history of type 1 diabetes was associated with a reduced risk of CHD independent of age, hypertension, and HDL cholesterol concentrations. The results were similar when the GADab+ patients were excluded from the analysis.

CONCLUSIONS

A family history of both type 1 and type 2 diabetes had a profound influence on the phenotype of patients with type 2 diabetes, which suggests a genetic interaction between type 1 and type 2 diabetes.

Postprandial metabolism of apolipoprotein B-48- and B-100-containing particles in type 2 diabetes mellitus: relations to angiographically verified severity of coronary artery disease

The aim of the present cross-sectional angiographic study was to examine if there is a relationship between the severity of CAD and postprandial lipemia in patients with type 2 diabetes mellitus. Special emphasis was directed to determining the contribution of apolipoprotein B-48 (apoB-48)-containing and B-100 (apoB-100)-containing triglyceride-rich particles to the magnitude of postprandial lipemia and degree of CAD. The role of apolipoprotein E (apoE) phenotype as a modulator of postprandial lipemia was also evaluated. The severity of CAD was determined by a quantitative coronary angiography and the subjects were classified into two groups based on the presence (severe CAD) or absence (mild CAD) of at least 50% stenosis in a major coronary vessel. The study population consisted of 43 subjects (31 men and 12 women) with fair glycemic control and comparable fasting lipids and body mass index. Postprandial responses of TG, apoB-48 and apoB-100 in lipoprotein subfractions (chylomicrons, VLDL1, VLDL2 and IDL) were determined after a fat load. Type 2 diabetic patients exhibited the classical dyslipidemia of the insulin resistance syndrome and delayed clearance of both hepatic and intestinal particles. Fasting or postprandial lipid or lipoprotein measurements, including apoB-48 and apoB-100 concentrations, did not differ between the groups. The presence or absence of apoE-4 allele did not significantly influence postprandial lipemia. The severity of the most significant coronary stenosis in angiography correlated with plasma and with chylomicron area under curve (AUC) for TG (n=27) and chylomicron AUC for apoB-48 (n=20). The strongest correlate of maximal stenosis was area under incremental curve (AUIC) for apoB-100 in IDL fraction (r=0.548, P=0. 012, n=20). In conclusion, postprandial apoB-48 and apoB-100 metabolism in triglyceride rich lipoproteins is distorted in type 2 diabetic patients, even in those with only mild CAD. The data suggest that postprandial change in small remnant particle numbers may contribute to the severity of CAD in type 2 diabetes.

Fibrinolytic proteins and progression of coronary artery disease in relation to gemfibrozil therapy

Impaired fibrinolytic function, mainly due to increased plasma plasminogen activator inhibitor-1 (PAI-1) activity, is common in patients with manifest coronary artery disease (CAD) and a predictor of recurrent cardiovascular events. We investigated the relationships of plasma tissue-type plasminogen activator (tPA) and PAI-1 antigen levels, plasma PAI-1 activity and PAI 4/5-guanosine (4G/5G) genotype to CAD progression in 203 middle-aged men participating in the Lopid Coronary Angiography Trial (LOCAT). A higher tPA antigen concentration, whether baseline or on-trial, was associated with a more severe global angiographic response (p < 0.05), an association mainly accounted for by progression of diffuse lesions in graft-affected segments (change in per-patient means of average diameters of segments haemodynamically related to bypass grafts). Plasma PAI-1 activity and mass concentration and 4G/5G PAI-1 genotype were unrelated to angiographic outcome measurements. tPA and PAI-1 antigen increased significantly in the gemfibrozil group (+11.3% and + 16.4%, respectively, p < 0.001), whereas there was no treatment effect on PAI-1 activity (median change 0.0%). It is concluded that fibrinolytic function does not substantially influence progression of CAD as assessed by angiography in middle-aged men. Furthermore, pronounced long-term lowering of serum triglycerides by gemfibrozil treatment does not significantly affect the plasma PAI-1 activity level but increases the plasma tPA and PAI-1 antigen concentrations.

Strategies for the management of diabetic dyslipidaemia

Atherosclerosis, the complication most prominently associated with type 2 diabetes and cardiovascular disease, represents a major burden for both individuals and society. Mortality rates associated with cardiovascular disease among patients with type 2 diabetes are at least 3 times those in the general population, and although 'traditional' cardiovascular risk factors affect patients with this disorder as they do other individuals, they do not account for the excess risk attached to type 2 diabetes. There is a growing body of evidence to show that hyperglycaemia and dyslipidaemia are connected with this excess cardiovascular risk: hypertriglyceridaemia has been implicated in several prospective clinical studies, and available data suggest that low density lipoprotein (LDL)-cholesterol is more atherogenic in patients with type 2 diabetes than in other individuals. It is possible that this increased atherogenicity is associated with a preponderance of small, dense LDL particles that are more prone to oxidation and glycation than larger fractions and that may be involved in endothelial dysfunction. These findings lead to the recommendation of mandatory global risk assessment, accompanied by good glycaemic control, aggressive lowering of serum levels of LDL-cholesterol and maintenance of serum levels of triglyceride at the lowest possible level in patients with type 2 diabetes.

Effect of heparin-stimulated plasma lipolytic activity on VLDL APO B subclass metabolism in normal subjects

Heparin given intravenously enhances lipolysis, although fasting lipids are not markedly altered in long-term administration. In the present study we investigated heparin-induced acute perturbation of VLDL subclass metabolism. Eight men were examined during a control study and during an 8.5 h infusion of heparin. 2H3-leucine was used as tracer and kinetic constants derived using a non-steady-state model. Heparin infusion increased both plasma lipoprotein and hepatic lipase activity and raised plasma FFAs two-fold (P < 0.001). The fractional catabolic rate (FCR) of VLDL1 apo B increased on heparin (25.7 +/- 4.2 and 10.8 +/- 1.7 pools/d, heparin vs. control, P < 0.02). The FCR of VLDL2 apo B increased to 12.6 +/- 1.9 pools/d on heparin vs. 8.8 +/- 1.1 pools/d during the control (NS). Total VLDL apo B production was not significantly changed (824 +/- 45 and 692 +/- 91 mg/d, heparin vs. control, NS). We conclude that during heparin infusion, the catabolism of especially large triglyceride-rich VLDL1 apo B is greatly increased. However, although the FFA levels were high during the heparin study, the production of total VLDL apo B did not rise. These findings are consistent with the known action of heparin on lipoprotein lipase but indicate that acute increase in plasma FFA levels does not lead to a rise in VLDL apo B production.

Delayed clearance of postprandial large TG-rich particles in normolipidemic carriers of LPL Asn291Ser gene variant

The carrier frequency of Asn291Ser polymorphism of the lipoprotein lipase (LPL) gene is 4;-6% in the Western population. Heterozygotes are prone to fasting hypertriglyceridemia and low high density lipoprotein (HDL) cholesterol concentrations especially when secondary factors are superimposed on the genetic defect. We studied the LPL Asn291Ser gene variant as a modulator of postprandial lipemia in heterozygote carriers. Ten normolipidemic carriers were compared to ten control subjects, who were selected to have similar age, sex, BMI, and apolipoprotein (apo)E-phenotype. The subjects were given a lipid-rich mixed meal and their insulin sensitivity was determined by euglycemic hyperinsulinemic clamp technique. The two groups had comparable fasting triglycerides and glucose utilization rate during insulin infusion, but fasting HDL cholesterol was lower in carriers (1.25 +/- 0.05 mmol/L) than in the control subjects (1. 53 +/- 0.06 mmol/L, P = 0.005). In the postprandial state the most pronounced differences were found in the very low density lipoprotein 1 (VLDL1) fraction, where the carriers displayed higher responses of apoB-48 area under the curve (AUC), apoB-100 AUC, triglyceride AUC, and retinyl ester AUC than the control subjects. The most marked differences in apoB-48 and apoB-100 concentrations were observed late in the postprandial period (9 and 12 h), demonstrating delayed clearance of triglyceride-rich particles of both hepatic and intestinal origin. Postprandially, the carriers exhibited enrichment of triglycerides in HDL fraction. Thus, in normolipidemic carriers the LPL Asn291Ser gene variant delays postprandial triglyceride, apoB-48, apoB-100, and retinyl ester metabolism in VLDL1 fraction and alters postprandial HDL composition compared to matched non-carriers.

Intense physical training decreases circulating antioxidants and endothelium-dependent vasodilatation in vivo

Physical training increases free radical production and consumes antioxidants. It has previously been shown that acute exercise markedly increases the susceptibility of LDL to oxidation but whether such changes are observed during physical training is unknown. We measured circulating antioxidants, lipids and lipoproteins, and blood flow responses to intrabrachial infusions of endothelium-dependent (acetylcholine, ACh, L-N-monomethyl-arginine, L-NMMA) and -independent (sodium nitroprusside, SNP) vasoactive agents, before and after 3 months of running in 9 fit male subjects. Maximal aerobic power increased from 53 +/- 1 to 58 +/- 2 ml/kg min (P < 0.02). All circulating antioxidants (uric acid, SH-groups, alpha-tocopherol, beta-carotene, retinol) except ascorbate decreased significantly during training. Endothelium-dependent vasodilatation in forearm vessels decreased by 32-35% (P < 0.05), as determined from blood flow responses to both a low (10.8 +/- 2.1 vs. 7.3 +/- 1.5 ml/dl min, 0 vs. 3 months) and a high (14.8 +/- 2.6 vs. 9.6 +/- 1.8) ACh dose. The % endothelium-dependent blood flow (% decrease in basal flow by L-NMMA), decreased through training from 37 +/- 3 to 22 +/- 7% (P < 0.05). Blood flow responses to SNP remained unchanged. The decrease in uric acid was significantly correlated with the change in the % decrease in blood flow by L-NMMA (r = 0.74, P < 0.05). The lag time for the susceptibility of plasma LDL to oxidation in vitro, LDL size and the concentration of LDL cholestetol remained unchanged. We conclude that relatively intense aerobic training decreases circulating antioxidant concentrations and impairs endothelial function in forearm vessels.

Chronic complications in patients with slowly progressing autoimmune type 1 diabetes (LADA)

OBJECTIVE

To study the prevalence of chronic diabetic complications in patients with the slowly progressing autoimmune form of type 1 diabetes, also referred to as latent autoimmune diabetes in adults (LADA).

RESEARCH DESIGN AND METHODS

We evaluated factors associated with chronic diabetic complications in 59 patients with GAD antibodies (GADAs) and age at onset of diabetes >35 years and in 59 GADA-negative type 2 diabetic patients. The prevalence of chronic complications was further compared with the prevalence in 111 type 1 diabetic patients.

RESULTS

The LADA patients had lower BMI (P = 0.04), waist-to-hip ratio (P = 0.02 for men and P = 0.03 for women), and fasting C-peptide concentrations (P<0.001) higher HDL2 concentrations (P = 0.04), and less hypertension (58 vs. 75%, P = 0.05) than the type 2 diabetic patients. These differences were even more marked in patients with short disease duration. The prevalence of retinopathy (51 vs. 56%), neuropathy (29 vs. 27%), and microalbuminuria (27 vs. 29%) did not differ between the groups. The type 1 diabetic patients had lower prevalence of neuropathy (13%, P = 0.02) and higher prevalence of retinopathy (76%, P = 0.002) compared with the other groups. Neither the prevalence of coronary heart disease (CHD) (56 vs. 58%) nor cardiovascular mortality (7.4 vs. 12.4%, P = 0.2) significantly differed between the LADA and type 2 diabetic patients. In a multiple logistic regression analysis, glycemic control was associated with CHD (P = 0.02) in the LADA group but not in the type 2 diabetic group.

CONCLUSIONS

Glycemic control is a stronger risk factor for cardiovascular disease in LADA patients than in patients with type 2 diabetes. This could be related to the lower prevalence of the metabolic syndrome seen in the former.

Postprandial hypertriglyceridemia and insulin resistance in normoglycemic first-degree relatives of patients with type 2 diabetes

BACKGROUND

Impaired ability to eliminate lipids in the postprandial state is an atherogenic trait associated with insulin resistance.

OBJECTIVE

To assess insulin sensitivity and postprandial triglyceride metabolism in prediabetic persons.

DESIGN

Cross-sectional study.

SETTING

Sahlgrenska University Hospital, Göteborg, Sweden.

PARTICIPANTS

13 healthy, normotriglyceridemic men with two first-degree relatives with type 2 diabetes and 13 carefully matched controls without known diabetes heredity.

MEASUREMENTS

Oral glucose tolerance test, insulin sensitivity (euglycemic clamp technique), and fasting and postprandial triglyceride levels after a mixed meal.

RESULTS

Relatives of persons with type 2 diabetes were insulin resistant but had normal glucose tolerance. They exhibited postprandial hypertriglyceridemia; the 6-hour triglyceride incremental area under the curve was 50% higher than that of the control group (P = 0.037).

CONCLUSIONS

These healthy male first-degree relatives of patients with type 2 diabetes are insulin resistant and exhibit postprandial lipid intolerance despite having normal fasting triglyceride levels. These characteristics, which occur in the absence of glucose intolerance, are associated with an increased risk for macroangiopathy.

Treatment of obese subjects with the oral growth hormone secretagogue MK-677 affects serum concentrations of several lipoproteins, but not lipoprotein(a)

Obesity is associated with blunted GH secretion and an unfavorable lipoprotein pattern. The objective of this study was to investigate the effects of treatment with the oral GH secretagogue MK-677 on lipoproteins in otherwise healthy obese males. The study was randomized, double blind, and parallel. Twenty-four obese males, aged 18-50 yr, with body mass index greater than 30 kg/m2 and waist/hip ratio above 0.95 were treated with 25 mg MK-677 (n = 12) or placebo (n = 12) daily for 8 weeks. MK-677 treatment did not significantly change serum lipoprotein(a) [Lp(a)] levels. Serum apolipoprotein A-I and E (apoA-I and apoE) were increased at 2 weeks (P < 0.001 and P < 0.01 vs. placebo, respectively), but were not changed at study end. Serum total cholesterol and low density lipoprotein (LDL) cholesterol (LDL-C) levels were not significantly changed by MK-677 treatment. Serum high density lipoprotein (HDL) cholesterol (HDL-C) was increased at 2 weeks of MK-677 treatment (P < 0.01 vs. placebo), but not at 8 weeks. The LDL-C/HDL-C ratio was reduced after 8 weeks of MK-677 treatment (P < 0.05 vs. placebo). Mean LDL particle diameter was decreased at 2 weeks (P < 0.05 vs. placebo), but was unchanged compared with baseline values at 8 weeks (P = NS vs. placebo). The level of serum triglycerides was increased at 2 (P < 0.05 vs. placebo), but not at 8, weeks. Lipoprotein lipase activity in abdominal and gluteal sc adipose tissue was not affected by active treatment. In conclusion, treatment with the oral GH secretagogue MK-677 affected circulating lipoproteins. The effects on serum apoA-1, apoE, triglycerides, and mean LDL particle diameter were transient. At study end, the LDL-C/HDL-C ratio was decreased. MK-677 treatment did not significantly affect serum Lp(a) concentrations at the present dose and administration protocol.