Not enough known about fenofibrate's kidney effects in people with Type 2 diabetes

Globally ≈10% of adults have diabetes, with 80% in disadvantaged regions, hence low-cost renoprotective agents are desirable. Fenofibrate demonstrated microvascular benefits in several cardiovascular end-point diabetes trials, but knowledge of effects in late-stage kidney disease is limited. We report new FIELD substudy data and call for further kidney outcomes data.

Relationship of low molecular weight fluorophore levels with clinical factors and fenofibrate effects in adults with type 2 diabetes

People with diabetes are at risk of chronic complications and novel biomarkers, such as Advanced glycation end-products (AGEs) may help stratify this risk. We assessed whether plasma low-molecular weight AGEs, also known as LMW-fluorophores (LMW-F), are associated with risk factors, predict complications, and are altered by fenofibrate in adults with type 2 diabetes. Plasma LMW-F were quantified at baseline, after six weeks fenofibrate, and one year post-randomisation to fenofibrate or placebo. LMW-F associations with existing and new composite vascular complications were determined, and effects of fenofibrate assessed. LMW-F correlated positively with age, glycated haemoglobin (HbA1c), pulse pressure, kidney dysfunction and inflammation; and negatively with urate, body mass index, oxidative stress and leptin, albeit weakly (r = 0.04–0.16, all p < 0.01). Independent determinants of LMW-F included smoking, diastolic blood pressure, prior cardiovascular disease or microvascular complications, Caucasian ethnicity, kidney function, HbA1c and diabetes duration (all p ≤ 0.01). Baseline LMW-F tertiles correlated with on-trial macrovascular and microvascular complications (trend p < 0.001) on univariate analyses only. Six weeks of fenofibrate increased LMW-F levels by 21% (p < 0.001). In conclusion, LMW-F levels correlate with many risk factors and chronic diabetes complications, and are increased with fenofibrate. LMW-F tertiles predict complications, but not independently of traditional risk factors.

The relationship of neutrophil elastase and proteinase 3 with risk factors, and chronic complications in type 2 diabetes: A Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) sub-study

INTRODUCTION

Neutrophil elastase (NE) and proteinase 3 (PR3) are novel inflammation biomarkers. We investigated their associations with chronic complications, determinants of biomarker levels and effects of fenofibrate in patients with type 2 diabetes mellitus (T2DM) from Fenofibrate Intervention and Event Lowering in Diabetes study.

METHODS

Plasma NE and PR3 levels were quantified at baseline (n = 2000), and relationships with complications over 5-years assessed. Effects of fenofibrate on biomarker levels (n = 200) were determined at four follow-up visits.

RESULTS

Higher waist-to-hip ratio, homocysteine and C-reactive protein and lower apoA-II were determinants of higher NE and PR3 levels. Higher NE levels were associated with on-trial stroke and cardiovascular mortality, and higher PR3 levels with on-trial stroke, but associations were not significant after adjustment for confounding factors. Although higher NE and PR3 levels were associated with baseline total microvascular disease, only NE levels were associated with on-trial neuropathy or amputation. These associations were not significant after adjusting for multiple comparisons. NE and PR3 levels did not change with fenofibrate.

CONCLUSIONS

In T2DM plasma NE and PR3 levels are associated with vascular risk factors, and total microvascular disease at baseline, but on rigorous analyses were not associated with on-trial complications. Levels were not changed by fenofibrate.

Uric acid predicts long-term cardiovascular risk in type 2 diabetes but does not mediate the benefits of fenofibrate: The FIELD study

AIM

To explore the relationship between baseline uric acid (UA) levels and long-term cardiovascular events in adults with type 2 diabetes (T2D) and to determine whether the cardioprotective effects of fenofibrate are partly mediated through its UA-lowering effects.

METHODS

Data from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial were utilized, comprising 9795 adults with T2D randomly allocated to treatment with fenofibrate or matching placebo. Plasma UA was measured before and after a 6-week, active fenofibrate run-in phase in all participants. Cox proportional hazards models were used to explore the relationships between baseline UA, pre-to-post run-in reductions in UA and long-term cardiovascular outcomes.

RESULTS

Mean baseline plasma UA was 0.33 mmol/L (SD 0.08). Baseline UA was a significant predictor of long-term cardiovascular events, with every 0.1 mmol/L higher UA conferring a 21% increase in event rate (HR 1.21, 95% CI 1.13-1.29, P < .001). This remained significant after adjustment for treatment allocation, cardiovascular risk factors and renal function. The extent of UA reduction during fenofibrate run-in was also a significant predictor of long-term cardiovascular events, with every 0.1 mmol/L greater reduction conferring a 14% lower long-term risk (HR 0.86, 95% CI 0.76-0.97, P = .015). This effect was not modified by treatment allocation (P_interaction = .77).

CONCLUSIONS

UA is a strong independent predictor of long-term cardiovascular risk in adults with T2D. Although greater reduction in UA on fenofibrate is predictive of lower cardiovascular risk, this does not appear to mediate the cardioprotective effects of fenofibrate.

Detecting episomal or integrated human papillomavirus 16 DNA using an exonuclease V-qPCR-based assay

Screening for human papillomavirus (HPV) integration into host cell chromosomes typically requires large amounts of time and reagents. We developed a rapid and sensitive assay based on exonuclease V (ExoV) and quantitative polymerase chain reaction (qPCR) to determine HPV genome configurations in cell lines and tissues. We established the assay using genomic DNA from cell lines known to harbor integrated or episomal HPV16. DNA was incubated with ExoV, which is specific for linear DNA, and the DNA fraction resistant to digestion was measured by qPCR. The percent of DNA resistant to ExoV digestion was calculated relative to undigested DNA for determination of episomal or integrated HPV16. The ExoV assay was accurate, capable of distinguishing episomal from integrated HPV16 in cell lines and tissues. Future applications of the ExoV assay may include screening of HPV genome configurations in the progression of HPV-associated cancers.

Effect of fenofibrate on uric acid and gout in type 2 diabetes: a post-hoc analysis of the randomised, controlled FIELD study

BACKGROUND

Gout is a painful disorder and is common in type 2 diabetes. Fenofibrate lowers uric acid and reduces gout attacks in small, short-term studies. Whether fenofibrate produces sustained reductions in uric acid and gout attacks is unknown.

METHODS

In the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial, participants aged 50-75 years with type 2 diabetes were randomly assigned to receive either co-micronised fenofibrate 200 mg once per day or matching placebo for a median of 5 years follow-up. We did a post-hoc analysis of recorded on-study gout attacks and plasma uric acid concentrations according to treatment allocation. The outcomes of this analysis were change in uric acid concentrations and risk of on-study gout attacks. The FIELD study is registered with ISRCTN, number ISRCTN64783481.

FINDINGS

Between Feb 23, 1998, and Nov 3, 2000, 9795 patients were randomly assigned to fenofibrate (n=4895) or placebo (n=4900) in the FIELD study. Uric acid concentrations fell by 20·2% (95% CI 19·9-20·5) during the 6-week active fenofibrate run-in period immediately pre-randomisation (a reduction of 0·06 mmol/L or 1 mg/dL) and remained -20·1% (18·5-21·7, p<0·0001) lower in patients taking fenofibrate than in those on placebo in a random subset re-measured at 1 year. With placebo allocation, there were 151 (3%) first gout events over 5 years, compared with 81 (2%) among those allocated fenofibrate (HR with treatment 0·54, 95% CI 0·41-0·70; p<0·0001). In the placebo group, the cumulative proportion of patients with first gout events was 7·7% in patients with baseline uric acid concentration higher than 0·36 mmol/L and 13·9% in those with baseline uric acid concentration higher than 0·42 mmol/L, compared with 3·4% and 5·7%, respectively, in the fenofibrate group. Risk reductions were similar among men and women and those with dyslipidaemia, on diuretics, and with elevated uric acid concentrations. For participants with elevated baseline uric acid concentrations despite taking allopurinol at study entry, there was no heterogeneity of the treatment effect of fenofibrate on gout risk. Taking account of all gout events, fenofibrate treatment halved the risk (HR 0·48, 95% CI 0·37-0·60; p<0·0001) compared with placebo.

INTERPRETATION

Fenofibrate lowered uric acid concentrations by 20%, and almost halved first on-study gout events over 5 years of treatment. Fenofibrate could be a useful adjunct for preventing gout in diabetes.

FUNDING

None.

Baseline Circulating FGF21 Concentrations and Increase after Fenofibrate Treatment Predict More Rapid Glycemic Progression in Type 2 Diabetes: Results from the FIELD Study

BACKGROUND

It is not known whether circulating fibroblast growth factor 21 (FGF21) concentrations are associated with glycemic progression in patients with established type 2 diabetes. This study reports this relationship in type 2 diabetes patients participating in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial.

METHODS

Plasma FGF21 was quantified in 9697 study participants. Among patients with lifestyle-only glucose control measures at baseline, glycemic progression was defined as the initiation of oral hypoglycemic agents or insulin therapy. We assessed the relationship of FGF21 concentrations with glycohemoglobin (Hb A1c), the homeostasis model assessment of β-cell function (HOMA-B) and insulin resistance (HOMA-IR), and glycemic progression.

RESULTS

Among 2584 patients with lifestyle-only glycemic therapy at baseline, plasma FGF21 concentrations were positively associated with HOMA-IR (5.1% increase per 100% increase in FGF21 concentrations). Patients with higher baseline plasma FGF21 concentrations had higher risk of glycemic progression over a 5-year period (P = 0.02), but the association was not significant after further adjusting for alanine aminotransferase (ALT) enzyme activity. During the fenofibrate active run-in phase, higher tertiles of fenofibrate-induced increase in FGF21 concentrations were associated with higher risk of glycemic progression (adjusted hazards ratio = 1.09 and 1.18 for tertiles 2 and 3, respectively, P for trend = 0.01), even after adjusting for ALT enzyme activity. This association was statistically significant in the fenofibrate group only (P = 0.01).

CONCLUSIONS

Higher baseline and fenofibrate-induced increase in FGF21 concentrations predict more rapid glycemic progression in type 2 diabetes patients. This association may be partly explained by hepatic function.

The interaction between human papillomavirus and other viruses

The etiological role of human papillomavirus (HPV) in anogenital tract and head and neck cancers is well established. However, only a low percentage of HPV-positive women develop cancer, indicating that HPV is necessary but not sufficient in carcinogenesis. Several biological and environmental cofactors have been implicated in the development of HPV-associated carcinoma that include immune status, hormonal changes, parity, dietary habits, tobacco usage, and co-infection with other sexually transmissible agents. Such cofactors likely contribute to HPV persistent infection through diverse mechanisms related to immune control, efficiency of HPV infection, and influences on tumor initiation and progression. Conversely, HPV co-infection with other factors may also harbor anti-tumor effects. Here, we review epidemiological and experimental studies investigating human immunodeficiency virus (HIV), herpes simplex virus (HSV) 1 and 2, human cytomegalovirus (HCMV), Epstein-Barr virus (EBV), BK virus (BKV), JC virus (JCV), and adeno-associated virus (AAV) as viral cofactors in or therapeutic factors against the development of genital and oral HPV-associated carcinomas.

The Effectiveness of Diabetes Education for Non-Insulin-Dependent Diabetic Persons

Individuals with noninsulin depend ent diabetes mellitus referred to a dia betes education programme were al located at random to treatment (n = 32) or non-treatment (n = 28) groups to assess the effectiveness of this pro gramme. The education course lasted four weeks, at the end of which the participants showed reductions of HbA1c and post-prandial glucose levels, improvement in knowledge and less anxiety. On the other hand, the control group experienced more anxiety and did not show significant changes in measured indices of glu cose control. Nevertheless, these im provements in glucose control were not sustained. Within four weeks of cessation of the intervention pro gramme, HbA1c and glucose levels were not significantly different from those measured at entry to the pro gramme. In addition, a delay of four weeks from the time of referral until initiation of education was associated with lack of significant reduction of HbA1c and glucose levels.

Relationship of fibroblast growth factor 21 with baseline and new on-study microvascular disease in the Fenofibrate Intervention and Event Lowering in Diabetes study

AIMS/HYPOTHESIS

Baseline circulating fibroblast growth factor 21 (FGF21) levels can predict total cardiovascular disease events in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study. This paper describes the relationship of baseline FGF21 levels and new on-study microvascular disease in patients with type 2 diabetes from the FIELD study.

METHODS

Baseline FGF21 levels were measured in plasma by enzyme-linked immunosorbent assay in 9697 study participants. Total microvascular disease was defined as the presence of any nephropathy, retinopathy, neuropathy and/or microvascular amputation. The relationship between FGF21 levels and microvascular disease was assessed by multivariable logistic regression.

RESULTS

Higher baseline FGF21 levels were found in patients with baseline total microvascular disease (p<0.001). The association remained significant after adjusting for potential confounding factors (OR [95% CI] 1.13 [1.08, 1.19] per SD increase in log e -transformed FGF21 levels, p<0.001). Of 6465 patients without baseline total microvascular disease, 1517 developed new on-study total microvascular disease over 5 years of follow-up. Higher baseline FGF21 levels were associated with a higher risk of new on-study total microvascular disease after adjusting for potential confounding factors (OR [95% CI] 1.09 [1.02, 1.16] per SD increase in log e -transformed FGF21 levels, p=0.01). Addition of FGF21 levels in a model of new on-study total microvascular disease with established risk factors significantly, but modestly, increased the integrated discrimination improvement and the net reclassification improvement (both p < 0.01).

CONCLUSIONS/INTERPRETATION

Higher baseline FGF21 levels are seen in patients with type 2 diabetes and established microvascular disease, and predict the future development of new microvascular disease.

The relationship of fibroblast growth factor 21 with cardiovascular outcome events in the Fenofibrate Intervention and Event Lowering in Diabetes study

AIMS/HYPOTHESIS

Circulating fibroblast growth factor 21 (FGF21) levels are often elevated in obesity, dyslipidaemia, insulin resistance and type 2 diabetes. This study investigated the relationship of plasma FGF21 levels with cardiovascular events in patients with type 2 diabetes.

METHODS

Plasma FGF21 levels were measured by ELISA at baseline in 9,697 individuals with type 2 diabetes participating in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study. We assessed the association of FGF21 levels with the incidence of different cardiovascular outcomes over 5 years. The primary outcome was total cardiovascular disease (CVD) events and the secondary outcomes were the four individual components: coronary heart disease events, total stroke, CVD mortality and coronary and carotid revascularisation. The tertiary outcome was hospitalisation for angina pectoris.

RESULTS

Higher baseline FGF21 levels were associated with higher risks of all cardiovascular outcome events after adjusting for the study treatment allocation (all p < 0.01). The associations remained significant for total CVD events and for coronary and carotid revascularisation after further adjusting for confounding factors, with the HR (95% CI) being 1.28 (1.10, 1.50) and 1.26 (1.01, 1.56), respectively, for the highest tertile compared with the lowest tertile (overall effect p = 0.002 and 0.007, respectively). The addition of FGF21 levels to a model including established CVD risk factors predicting total CVD events led to a non-significant increase in the C-statistic but there was a significant improvement in integrated discrimination and net reclassification.

CONCLUSIONS/INTERPRETATION

Higher baseline plasma FGF21 levels were associated with higher risk of cardiovascular events in patients with type 2 diabetes.

TRIAL REGISTRATION

ISRCTN64783481.

Pharmacokinetic comparison of a generic coenzyme Q₁₀ solubilizate and a formulation with soybean phytosterols

Coenzyme Q₁₀ (CoQ₁₀) is essential for all cells, and deficiency has been implicated in cardiovascular disease. Plant phytosterols inhibit cholesterol absorption, and may thereby also reduce cardiovascular risk. This study compared the relative bioavailability of CoQ₁₀ solubilized in low-dose soybean phytosterols (SterolQ₁₀) with a generic CoQ₁₀ solubilizate. In a randomized, cross-over design, 36 healthy males received a single 100 mg dose of CoQ₁₀, as SterolQ₁₀ or generic CoQ₁₀, with a two-week washout between treatments. Plasma CoQ₁₀ was analysed at baseline, and at 2, 4, 6, 8 and 10 h after supplement ingestion. Subjects were then administered either 100 mg/day of generic CoQ₁₀ or SterolQ₁₀ for 4 weeks. Fasting plasma CoQ₁₀ levels were measured at baseline and following supplementation. The two preparations were bioequivalent in regard to the area under the curve (AUC(0-10h) ) and maximum increase in concentration (C(max) ), with geometric mean ratios of 0.89 (CI 0.81-0.98) and 0.88 (CI 0.80-0.96), respectively. Four-weeks of CoQ₁₀ resulted in a comparable twofold increase in CoQ₁₀ levels for both formulations (p < 0.001), which was similar between preparations (p = 0.74). The combined CoQ₁₀ and phytosterol formulation, SterolQ₁₀, showed bioequivalence to the generic CoQ₁₀ following a single CoQ₁₀ dose, and demonstrated comparable bioavailability following multiple dose administration.

Effects of fenofibrate on renal function in patients with type 2 diabetes mellitus: the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) Study

AIMS/HYPOTHESIS

Fenofibrate caused an acute, sustained plasma creatinine increase in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) and Action to Control Cardiovascular Risk in Diabetes (ACCORD) studies. We assessed fenofibrate's renal effects overall and in a FIELD washout sub-study.

METHODS

Type 2 diabetic patients (n = 9,795) aged 50 to 75 years were randomly assigned to fenofibrate (n = 4,895) or placebo (n = 4,900) for 5 years, after 6 weeks fenofibrate run-in. Albuminuria (urinary albumin/creatinine ratio measured at baseline, year 2 and close-out) and estimated GFR, measured four to six monthly according to the Modification of Diet in Renal Disease Study, were pre-specified endpoints. Plasma creatinine was re-measured 8 weeks after treatment cessation at close-out (washout sub-study, n = 661). Analysis was by intention-to-treat.

RESULTS

During fenofibrate run-in, plasma creatinine increased by 10.0 μmol/l (p < 0.001), but quickly reversed on placebo assignment. It remained higher on fenofibrate than on placebo, but the chronic rise was slower (1.62 vs 1.89 μmol/l annually, p = 0.01), with less estimated GFR loss (1.19 vs 2.03 ml min(-1) 1.73 m(-2) annually, p < 0.001). After washout, estimated GFR had fallen less from baseline on fenofibrate (1.9 ml min(-1) 1.73 m(-2), p = 0.065) than on placebo (6.9 ml min(-1) 1.73 m(-2), p < 0.001), sparing 5.0 ml min(-1) 1.73 m(-2) (95% CI 2.3-7.7, p < 0.001). Greater preservation of estimated GFR with fenofibrate was observed with baseline hypertriacylglycerolaemia (n = 169 vs 491 without) alone, or combined with low HDL-cholesterol (n = 140 vs 520 without) and reductions of ≥ 0.48 mmol/l in triacylglycerol over the active run-in period (pre-randomisation) (n = 356 vs 303 without). Fenofibrate reduced urine albumin concentrations and hence albumin/creatinine ratio by 24% vs 11% (p < 0.001; mean difference 14% [95% CI 9-18]; p < 0.001), with 14% less progression and 18% more albuminuria regression (p < 0.001) than in participants on placebo. End-stage renal event frequency was similar (n = 21 vs 26, p = 0.48).

CONCLUSIONS/INTERPRETATION

Fenofibrate reduced albuminuria and slowed estimated GFR loss over 5 years, despite initially and reversibly increasing plasma creatinine. Fenofibrate may delay albuminuria and GFR impairment in type 2 diabetes patients. Confirmatory studies are merited.

TRIAL REGISTRATION

ISRCTN64783481.

What is the best predictor of the atherogenic LDL subclass phenotype 'pattern B' in patients with type 2 diabetes mellitus?

BACKGROUND

The atherogenic lipoprotein phenotype 'pattern B' comprises a predominance of small-dense low-density lipoprotein (sdLDL). Gradient gel electrophoresis (GGE) is considered a 'gold standard' method for identifying this phenotype, but is impractical for routine laboratory use. The low-density lipoprotein cholesterol:apolipoprotein-B (LDL-C:Apo-B) ratio has been advocated as a surrogate marker for sdLDL and a direct assay for sdLDL has recently become available. We compared the sdLDL assay and LDL-C:Apo-B with more established lipid parameters to predict the presence of 'pattern B' phenotype.

METHOD

Blood was collected from 97 fasted subjects on three separate occasions. Total cholesterol, triglyceride, Apo-B and sdLDL were measured; LDL- and HDL-cholesterol were determined after ultracentrifugation. The predominant LDL particle size and phenotype were assigned by GGE.

RESULTS

'Pattern B' phenotype was identified in 36% of samples. Peak particle size showed a positive correlation with HDL-cholesterol and a negative correlation with triglyceride and Apo-B. Receiver operating curve (ROC) analysis showed triglyceride:HDL-C ratio and triglyceride alone to be the best predictors of 'pattern B' phenotype, with area under the curve (AUC) being 0.87 and 0.84, respectively. AUCs for sdLDL (0.74) and LDL-C:Apo-B (0.71) were significantly lower (P < 0.05). A high sdLDL concentration had the greatest specificity (95%) and positive predictive value (74%) for 'pattern B' phenotype, but low sensitivity (43%).

CONCLUSION

Direct measurement of sdLDL provided the most specific predictor of 'pattern B' phenotype, whereas triglyceride:HDL-C ratio or triglycerides alone, parameters readily available in most laboratories, were the best predictors by ROC analysis.

The fungicide ciclopirox inhibits lymphatic endothelial cell tube formation by suppressing VEGFR-3-mediated ERK signaling pathway

Ciclopirox olamine (CPX), an off-patent antifungal agent used to treat mycoses of skin and nails, has recently been demonstrated to be a potential anticancer agent. However, the underlying mechanism is not well understood. Here for the first time we show that CPX inhibited lymphangiogenesis in an in vitro model (tube formation). This effect was in part associated with inhibition of vascular endothelial growth factor receptor 3 (VEGFR-3) expression, as overexpression of VEGFR-3 conferred partial resistance to CPX inhibitory effect on tube formation in lymphatic endothelial cells (LECs), whereas downregulation of VEGFR-3 mimicked the effect of CPX, blocking the tube formation. Further study revealed that CPX did not alter mRNA level, but inhibited protein synthesis and promoted protein degradation of VEGFR-3. In addition, we found that CPX inhibited phosphorylation of the extracellular signal-related kinase 1/2 (ERK1/2), a downstream effector of VEGFR-3. Overexpression of VEGFR-3 attenuated CPX inhibition of ERK1/2 phosphorylation, whereas downregulation of VEGFR-3 inhibited extracellular signal-related kinase 1/2 (ERK1/2) phosphorylation in LECs. Ectopic expression of constitutively active mitogen -activated protein kinase kinase 1 (MKK1) resulted in activation of ERK1/2, and partially prevented CPX inhibition of LEC tube formation. The results suggest that CPX inhibits LEC tube formation at least in part through inhibiting VEGFR-3-mediated ERK signaling pathway.

Fibrates plus betaine: a winning combination?

Because most of the cardiac risk remains despite successful statin therapy there has been renewed interest in fibrate therapy for persisting hyperlipidaemia. Fibrate therapy lowers triglycerides but causes the urinary loss of betaine, which is an essential metabolite that is involved in osmoregulation, in methyl group metabolism, and which also affects lipid partitioning in the body. Loss of betaine is associated with an elevation of homocysteine and may compromise the potential benefits of fibrate therapy. However, betaine deficiency could be easily and inexpensively corrected by concurrent betaine supplementation. Clinical trials of combinations of betaine and fibrate, to complement statin therapy, are needed to determine the value of these agents in reducing the residual cardiovascular disease risk.

Plasma sex hormone-binding globulin, corticosteroid-binding globulin, cortisol, and free cortisol levels in outpatients attending a lipid disorders clinic: a cross-sectional study of 1137 subjects

We measured plasma sex hormone-binding globulin (SHBG), corticosteroid-binding globulin (CBG), and total cortisol, and calculated free plasma cortisol in 1 137 subjects attending a hospital outpatient lipid disorders clinic to investigate whether or not these analytes correlated with the degree of insulin resistance and the presence of the metabolic syndrome. In both males and females, plasma SHBG correlated inversely with anthropometric measures and with fasting glucose, insulin, insulin resistance, and triglycerides, and positively with HDL-cholesterol. However, in males with the metabolic syndrome, unlike females, the relationship between SHBG, some anthropometric measures, fasting glucose, insulin, and HDL-cholesterol were lost, which suggests that in males SHBG may not co-cluster with other components of the metabolic syndrome. In males and males with the metabolic syndrome, total plasma cortisol and calculated plasma free cortisol correlated positively with fasting glucose. Corticosteroid-binding globulin correlated inversely with percentage body fat and positively with HDL-cholesterol in males with and without the metabolic syndrome. CBG correlated negatively with age in both sexes. Overall, the results confirm the finding that SHBG is a marker of insulin resistance in males and females and that SHBG is associated with fasting triglycerides in males with the metabolic syndrome. Importantly, SHBG could be considered a stronger component of the metabolic syndrome in females than in males. However, the aetiological role of CBG and cortisol in insulin resistance is uncertain, although in males, cortisol and CBG could be subtly related to the degree of insulin resistance.

Variability in measurements of blood glucose response to foods in human subjects is not reduced after a standard breakfast

Measurements of blood glucose response to food are highly variable. We determined whether within-individual variability in data for blood glucose responses were reduced if individuals consumed a standard meal 2 hours before testing and investigated the effect of serving size. Blood glucose responses to muesli and macaroni cheese were determined in 13 individuals by taking 2 fasting capillary blood samples. Food was then consumed, and capillary blood samples were taken every 15 minutes for the first hour and every 30 minutes for the second hour. The incremental area under the blood glucose response curve was determined, and glycemic glucose equivalents (GGEs) were calculated. The GGE values were not significantly different whether the muesli and macaroni cheese were fed fasting or after a standard breakfast (29.2 vs 34.5 g for muesli and 11.0 vs 14.6 g for macaroni cheese). Within-individual coefficients of variation were not significantly different whether the food was consumed fasting or after a standard breakfast (24.9% and 32.5% for muesli and 38.1% and 59.4% for macaroni cheese). Differences in GGE between measured and estimated half serving size for macaroni cheese were 0.8 g (P = .6) and for muesli, 3 g (P = .2); for the double serving size for macaroni cheese, 1.7 g (P = .7); and for muesli, 6.7 g (P = .06). The GGE values for foods and variability in blood glucose response within individuals were not significantly different whether individuals fasted or consumed a standard breakfast before testing. However, blood glucose levels tended to differ significantly after consumption of the double serving size of muesli compared with other serving sizes.

Plasma levels of sex hormone-binding globulin, corticosteroid-binding globulin and cortisol in overweight subjects who develop impaired fasting glucose: a 3-year prospective study

Circulating sex hormone-binding globulin (SHBG), corticosteroid-binding globulin (CBG), and total and calculated free cortisol were measured in 206 overweight subjects to investigate whether or not they were markers of insulin resistance. Measurements were carried out on two occasions 36 months apart and subjects were grouped according to fasting plasma glucose. Fifty-one subjects, with a normal basal fasting glucose (<5.6 mmol/l) developed impaired fasting glucose 3 years later (> or = 5.6 mmol/l). Analysis either in toto or based on gender showed a highly significant increase in fasting insulin and insulin resistance, a modest increase in body mass index (BMI), but importantly no change in plasma SHBG, CBG, or cortisol concentrations. Subjects (n=101) with a normal fasting glucose both at baseline (<5.6 mmol/l) and at 36 months showed no significant change in fasting insulin, insulin resistance, SHBG, CBG, cortisol, or BMI. Cross-sectional analysis of the study population showed that plasma SHBG correlated negatively with insulin resistance both in men and women. Overall SHBG at baseline was not predictive of changes in fasting glucose. In females, plasma CBG correlated negatively with BMI. The major finding is that overweight subjects who developed impaired fasting glucose showed no significant change in plasma SHBG, CBG or cortisol, and therefore these indices are probably not early markers of insulin resistance in overweight subjects.

Lipid-altering efficacy and safety of simvastatin 80 mg/day: long-term experience in a large group of patients with hypercholesterolemia. World Wide Expanded Dose Simvastatin Study Group

BACKGROUND

Elevated levels of low-density lipoprotein (LDL) cholesterol promote the development of atherosclerosis and coronary heart disease.

HYPOTHESIS

Simvastatin 80 mg/day will be more effective than simvastatin 40 mg/day at reducing LDL cholesterol and will be well tolerated.

METHODS

Two similar, randomized, multicenter, controlled, double-blind, parallel-group, 48-week studies were performed to evaluate the long-term lipid-altering efficacy and safety of simvastatin 80 mg/day in patients with hypercholesterolemia. One study conducted in the US enrolled patients meeting the National Cholesterol Education Program (NCEP) LDL cholesterol criteria for pharmacologic treatment. In the other multinational study, patients with LDL cholesterol levels > or = 4.2 mmol/l were enrolled. At 20 centers in the US and 19 countries world-wide, 1,105 hypercholesterolemic patients, while on a lipid-lowering diet, were randomly assigned at a ratio of 2:3 to receive simvastatin 40 mg (n = 436) or 80 mg (n = 669) once daily for 24 weeks. Those patients completing an initial 24-week base study were enrolled in a 24-week blinded extension. Patients who had started on the 80 mg dose in the base study continued on the same dose in the extension, while those who had started on the 40 mg dose were rerandomized at a 1:1 ratio to simvastatin 40 or 80 mg in the extension.

RESULTS

There was a significant advantage in the LDL cholesterol-lowering effect of the 80 mg dose compared with that of the 40 mg dose, which was maintained over the 48 weeks of treatment. The mean percentage reductions (95% confidence intervals) from baseline in LDL cholesterol for the 40 and 80 mg groups were 41% (42, 39) and 47% (48, 46), respectively, for the 24-week base study, and 41% (43, 39) and 46% (47, 45), respectively, after 48 weeks of treatment (p < 0.001 between groups). Larger reductions in total cholesterol and triglycerides were also observed with the 80 mg dose compared with the 40 mg dose at Weeks 24 and 48. Both doses were well tolerated, with close to 95% of patients enrolled completing the entire 48 weeks of treatment. Myopathy (muscle symptoms plus creatine kinase increase > 10 fold upper limit of normal) and clinically significant hepatic transaminase increases (> 3 times the upper limit of normal) occurred infrequently with both doses. There was no significant difference between the groups in the number of patients with such increases, although there were more cases for both with the 80 mg dose.

CONCLUSIONS

Compared with the 40 mg dose, simvastatin 80 mg produced greater reductions in LDL cholesterol, total cholesterol, and triglycerides. Both doses were well tolerated.

Comparison of insulin resistance, metabolic syndrome and adiponectin in overweight bipolar patients taking sodium valproate and controls

OBJECTIVE

Metabolic abnormalities in patients with bipolar disorder may be secondary to obesity, aspects of the disorder or its treatment. To investigate this further, the purpose the present study was to compare insulin resistance, components of the metabolic syndrome and adiponectin levels in a group of overweight bipolar patients taking sodium valproate and a group of non-psychiatric control subjects.

METHODS

Data were collected from 60 overweight bipolar patients who had experienced clinically significant weight gain thought to be related to sodium valproate treatment and from 60 control subjects without psychiatric illness matched for age, gender, body mass index and ethnicity.

RESULTS

The frequency of the metabolic syndrome was high in both groups (50% and 32%, respectively), although not significantly different between groups (p = 0.06). Similar frequencies of insulin resistance (HOMA-IR), abdominal obesity, hypertriglyceridaemia, hypertension and fasting hyperglycaemia were found in both groups. High-density lipoprotein cholesterol levels were lower in patients (p = 0.006), while adiponectin was unexpectedly higher than in control subjects (9.6+/-5.9 microg mL(-1) vs 7.4+/-4.3 microg mL(-1), p = 0.03). The frequencies of insulin resistance (HOMA-IR), the metabolic syndrome and its individual components were not significantly different in patients taking atypical antipsychotic medication and patients not on these medications.

CONCLUSIONS

Frequencies of insulin resistance and the metabolic syndrome were similar in bipolar patients taking sodium valproate and matched control subjects, but dyslipidaemia was more frequent. Adiponectin levels were higher in patients. Further research is required to clarify the reasons for these findings.

Considerable temporal variability in glucose reference curves in humans for a year period

Glycemic glucose equivalent (GGE) is a measure of the blood glucose response to a defined portion of food. Their calculation requires the measurement of a standard glucose-response curve, with beverages containing 0, 12.5, 25, 50, and 75 g of glucose measured twice each. This study was designed to determine the stability of an individual's glucose-response curve measured every 3 months for a year and of their GGE estimates for 10 foods for that period. The blood glucose response to beverages containing 0, 12.5, 25, 50, and 75 g glucose and to 10 foods was measured for 16 healthy individuals. Capillary blood samples were collected fasting, then every 15 minutes for 1 hour, and every 30 minutes for at least 2 hours. The slopes and intercepts of the 4 glucose curves and the GGE of the 10 foods calculated using the available curves for each food was compared. The results showed considerable temporal variability in the slope (intraindividual coefficient of variation (CV) = 30%) and intercept (intraindividual CV = 40%) of the glucose curves. However, if GGE values were categorized into 3 groups (low GGE, < or = 10; medium GGE, 10.01-19.99; and high GGE, > or = 20), all but one food was consistently classified in the same category across the 4 glucose curves. In conclusion, it appears that if the exact GGE value is required, glucose curves should be repeated at least once every 3 months, but if foods are classed into general GGE categories, it may be possible to use the same glucose curve for a longer period.

Plasma retinol-binding protein is not a marker of insulin resistance in overweight subjects: a three year longitudinal study

OBJECTIVES

This longitudinal study investigated whether or not plasma retinol-binding protein (RBP), recently referred to as RBP4, was a marker of insulin resistance in overweight subjects.

METHODS

We measured anthropometric markers as well as RBP, fasting glucose and insulin in 206 overweight subjects and repeated these measurements 36 months later. Subjects were grouped according to fasting plasma glucose concentration at baseline and 36 months.

RESULTS

Subjects (n=51) with a normal basal fasting glucose (<5.6 mmol/L) who developed impaired fasting glucose (IFG) 3 years later (>or=5.6 mmol/L) showed a highly significant increase in both fasting insulin and insulin resistance, but importantly no change in plasma RBP. This group had a significant increase in body mass index (BMI). Subjects (n=101) with a normal fasting glucose at both baseline (<5.6 mmol/L) and 36 months showed no significant change in fasting insulin, insulin resistance, RBP or BMI. The remaining subjects had impaired basal fasting glucose and were not analysed on a group-wise basis. Overall, RBP correlated significantly, but inversely, with anthropometric measures, but not with fasting glucose, insulin or insulin resistance.

CONCLUSIONS

This is the first report of a long-term longitudinal study on RBP and the major finding is that subjects who developed insulin resistance showed no change in plasma RBP. On the basis of our results we consider that RBP cannot be construed as a marker of insulin resistance in overweight humans.

Effect of atorvastatin on plasma levels of asymmetric dimethylarginine in patients with non-ischaemic heart failure

BACKGROUND

Elevated plasma levels of asymmetric dimethylarginine (ADMA), an endothelial nitric oxide synthase (eNOS) inhibitor, may contribute to endothelial dysfunction in chronic heart failure (CHF). Since statins upregulate eNOS and ameliorate endothelial dysfunction in non-ischaemic CHF, we hypothesized that this may be in part through modification of ADMA.

AIM

To evaluate the effect of atorvastatin on the relationship between ADMA and endothelial function in non-ischaemic CHF.

METHODS

Twenty-four patients with CHF (ejection fraction <40%, New York Heart Association Functional Classes II and III) were randomised to atorvastatin treatment (40 mg) or placebo once daily for 6 weeks in a double-blinded, placebo-controlled crossover study. Plasma ADMA and l-arginine levels were measured by HPLC. Endothelial function was assessed by flow-mediated dilatation and invasive forearm plethysmography.

RESULTS

Post-statin therapy, endothelial function was improved (p<0.05) independent of LDL-cholesterol reductions, but no changes were observed in ADMA levels or the l-arginine to ADMA ratio. There was a trend for ADMA to inversely correlate with endothelial function at baseline.

CONCLUSIONS

Short-term atorvastatin treatment in non-ischaemic CHF improves endothelial function but has no effect on ADMA or the l-arginine to ADMA ratio. Our finding suggests that the observed statin-induced improvements in endothelial function are likely mediated via alternative pathways.

All-cause mortality in insulin-treated diabetic patients: a 20-year follow-up

AIMS

To establish all-cause mortality rates, and risk factors for mortality in insulin-treated diabetic individuals living in Canterbury, New Zealand.

METHODS

Insulin-treated diabetic subjects (n=995) on the Canterbury Diabetes Registry were followed up over 20-year and vital status determined. Death rates were standardised and hazard regression was used to model the effects of demographic covariates on relative survival time.

RESULTS

Six subjects had emigrated, the remaining 989 diabetic subjects contributed a total of 13705.53 person-years of follow-up, a mean of 13.7 years per subject. During follow-up 525 deaths occurred in subjects' aged 17.3-96.7, (261 females, 264 males). All-cause mortality rates in diabetic subjects exceeded those in the general population at all ages. SMRs were slightly higher for females than males in almost all age-at-onset groups, being 2.48 (95% CI: 2.18-2.78) for females and 2.17 (95% CI: 1.91-2.43) for males overall, but reaching a peak in the <30 age at onset group for both females and males being 4.25 (3.07-5.44) and 3.26 (2.49-4.03), respectively.

CONCLUSIONS

Mortality rates for diabetic individuals remain high, resulting in shortened life spans relative to the general population. This study provides a baseline for further studies of mortality and changes in mortality within New Zealand.

Cause-specific mortality in insulin-treated diabetic patients: a 20-year follow-up

BACKGROUND

Diabetes is one of the most common chronic diseases in Western populations. There have been few large published cohort studies of diabetes with 20 years of follow-up worldwide, and none other than the present one in NZ.

AIMS

To establish cause-specific death rates, by age and sex in insulin-treated diabetic individuals living in Canterbury, NZ.

METHODS

Insulin-treated diabetic subjects on the Canterbury Diabetes Registry were followed over 20 years and vital status determined. Following notification of deaths, age- and sex-specific mortality rates, and sex-specific mortality ratios (SMRs) were calculated.

RESULTS

During follow-up 966 diabetic subjects contributed 13,495 person-years and 525 deaths occurred (261 females and 264 males). At all ages mortality rates were considerably higher than expected mortality. Relative mortalities were increased for cardiovascular (SMR women 3.73, 95% CI: 3.16-4.30; men 3.27, 95% CI: 2.76-3.78), renal (SMR women 5.55, 95% CI: 2.53-8.57; men 7.15, 95% CI: 3.40-10.90), respiratory disease (SMR women 3.31, 95% CI: 1.98-4.63; men 2.32, 95% CI: 1.41-3.23) and malignancy (SMR women 4.99, 95% CI: 2.99-6.99; men 2.19, 95% CI: 1.42-2.96) with cardiovascular disease accounting for the single greatest cause of excess death at all ages.

CONCLUSIONS

Mortality rates for diabetic individuals remain high, resulting in shortened life spans relative to the general population. To reduce these death rates attention must be paid to the early detection and treatment of CVD and associated risk factors.

Plasma retinol-binding protein is unlikely to be a useful marker of insulin resistance

To assess whether plasma retinol-binding protein (RBP) is a marker of insulin resistance we measured RBP, insulin and glucose in 285 fasting subjects attending a Lipid Disorders Clinic as outpatients. They were grouped as either subjects without diabetes mellitus and with varying degrees of insulin resistance or subjects with diabetes mellitus according to the WHO criteria. We show that there was no association between plasma RBP and insulin-resistance, insulin, glucose, % body fat, waist circumference or BMI whether analysed together or in groups. We confirm, using the largest study cohort to date, that plasma RBP is unlikely to be a useful marker of insulin resistance.

Effect of coenzyme Q(10) supplementation on simvastatin-induced myalgia

Myalgia is the most frequently reported adverse side effect associated with statin therapy and often necessitates reduction in dose, or the cessation of therapy, compromising cardiovascular risk management. One postulated mechanism for statin-related myalgia is mitochondrial dysfunction through the depletion of coenzyme Q(10), a key component of the mitochondrial electron transport chain. This pilot study evaluated the effect of coenzyme Q(10) supplementation on statin tolerance and myalgia in patients with previous statin-related myalgia. Forty-four patients were randomized to coenzyme Q(10) (200 mg/day) or placebo for 12 weeks in combination with upward dose titration of simvastatin from 10 mg/day, doubling every 4 weeks if tolerated to a maximum of 40 mg/day. Patients experiencing significant myalgia reduced their statin dose or discontinued treatment. Myalgia was assessed using a visual analogue scale. There was no difference between combined therapy and statin alone in the myalgia score change (median 6.0 [interquartile range 2.1 to 8.8] vs 2.3 [0 to 12.8], p = 0.63), in the number of patients tolerating simvastatin 40 mg/day (16 of 22 [73%] with coenzyme Q(10) vs 13 of 22 [59%] with placebo, p = 0.34), or in the number of patients remaining on therapy (16 of 22 [73%] with coenzyme Q(10) vs 18 of 22 [82%] with placebo, p = 0.47). In conclusion, coenzyme Q(10) supplementation did not improve statin tolerance or myalgia, although further studies are warranted.

Short-term statin treatment improves endothelial function and neurohormonal imbalance in normocholesterolaemic patients with non-ischaemic heart failure

OBJECTIVES

To investigate the effect of short-term statin treatment on impaired endothelium-dependent vasodilatation and haemodynamic abnormalities typically occurring in chronic heart failure (CHF).

METHODS

In a double-blind, crossover study endothelium-dependent vasodilatation was measured in conduit and resistance vessels of 23 patients with non-ischaemic CHF after 6 weeks of placebo and 40 mg atorvastatin. The haemodynamic impact was assessed by cardioendocrine hormones, echocardiography and clinical indicators of CHF.

RESULTS

Cholesterol concentrations were population average (low density lipoprotein 3.56 (SEM 0.16) mmol/l, triglycerides 1.70 (0.20) mmol/l and high density lipoprotein 1.17 (0.07) mmol/l). In resistance vessels, the area under the curve ratio during acetylcholine infusion increased from 9.2 (1.9) with placebo to 12.2 (2.1) with statin (p < 0.01). This improvement was reversed during co-infusion with the nitric oxide antagonist N(G)-monomethyl-L-arginine. In conduit arteries, flow-mediated dilatation increased from 5.64 (SEM 0.88)% with placebo to 6.83 (0.97)% with statin (p < 0.05). Endothelium-independent vasodilatation did not change (p = 0.68 for conduit and p = 0.45 for resistance vessels). Endothelin 1 and atrial natriuretic peptide (ANP) decreased from 1.57 (0.08) and 51.3 (1.0) with placebo to 1.42 (0.09) pg/ml (p < 0.05) and 42.1 (7.5) pmol/l (p < 0.05), respectively, with statin.

CONCLUSIONS

In patients with non-ischaemic CHF and population-average cholesterol concentrations, short-term statin treatment improves endothelial function in conduit and resistance vessels and lowers plasma endothelin 1 and ANP concentrations.

Epstein-Barr virus shed in saliva is high in B-cell-tropic glycoprotein gp42

Epstein-Barr virus is an orally transmitted human herpesvirus that infects epithelial cells and establishes latency in memory B lymphocytes. Movement of virus between the two cell types is facilitated by changes in amounts of an envelope glycoprotein, gp42, which are effected by interaction of gp42 with HLA class II in a B cell. Here we used the differential ability of virus to bind to CD21-positive B cells and CD21-negative epithelial cells, which is also influenced by levels of gp42, to determine that the majority of virus shed in saliva is derived from an HLA class II-negative cell.

Comparative effects of enzogenol and vitamin C supplementation versus vitamin C alone on endothelial function and biochemical markers of oxidative stress and inflammation in chronic smokers

Chronic smoking is associated with endothelial dysfunction and inflammation, with oxidative stress contributing to both these processes. In this study, we investigated the effect of combined antioxidant treatment with Enzogenol, a flavonoid extract from the bark of Pinus radiata and vitamin C, over and above vitamin C alone, on endothelial function, plasma markers of inflammation and oxidative stress, blood pressure (BP) and anthropometrics. Forty-four chronic smokers without established cardiovascular disease were assigned randomly to receive either 480 mg Enzogenol and 60 mg vitamin C, or 60 mg vitamin C alone daily for 12 weeks. Endothelial function in the brachial artery was assessed by flow-mediated vasodilation (FMD). FMD improved in both treatment groups (p < 0.001), with no significant difference between the two groups (p = 0.84). In the group receiving Enzogenol and vitamin C, protein carbonyl levels were significantly reduced compared to the group taking vitamin C alone (p = 0.03). Enzogenol and vitamin C resulted in a significant reduction in fibrinogen levels in heavy smokers compared with vitamin C alone (p < 0.009). These findings demonstrated that co-supplementation with Enzogenol and vitamin C in smokers conferred no additional beneficial effect on macrovascular endothelial function over and above that seen in the vitamin C alone group. However, Enzogenol did demonstrate additional favourable effects on protein oxidative damage and fibrinogen levels.

Endothelium-ameliorating effects of statin therapy and coenzyme Q10 reductions in chronic heart failure

Although not currently indicated for chronic heart failure (CHF), statins have been associated with improved outcome in retrospective analysis. However, statin therapy reduces plasma levels of coenzyme Q(10) (ubiquinone), which may have adverse effects on heart failure states. We hypothesized that atorvastatin treatment improves endothelial function in patients with chronic heart failure independent of LDL-cholesterol alterations. Furthermore, we assessed how reductions in coenzyme Q(10) levels impact on potentially improved endothelial function. Twenty-four patients with stable, symptomatic heart failure (New York Heart Association Class II or III) and a left ventricular ejection fraction <40% were randomised to 40 mg atorvastatin or placebo for 6 weeks and crossed over to the other treatment arm for a further 6 weeks, after a 2-week wash out. Forearm resistance vessel function was assessed by venous occlusion plethysmography during infusion of acetylcholine (ACh), sodium nitroprusside (SNP), and N(G)-monomethyl-L-arginine (L-NMMA) into the brachial artery. Atorvastatin treatment lowered triglycerides, LDL-cholesterol and coenzyme Q(10) levels (all p<0.001) and improved endothelium-dependent vasodilatation during acetylcholine infusion (p=0.015). Endothelium-dependent forearm blood flow improvements correlated with reductions in coenzyme Q(10) levels (p=0.011), but not with LDL-cholesterol levels (p=0.084). Coenzyme Q(10) remained the significant variable predicting improvement in NO dependent endothelial function after adjusting for LDL-cholesterol levels (p=0.041). In conclusion, short-term atorvastatin therapy improved endothelial function in chronic heart failure patients. Further studies are required to determine whether coenzyme Q(10) reductions are limiting the maximum favourable effects of statin therapy on the microcirculation.

Homocysteine, glycine betaine, and N,N-dimethylglycine in patients attending a lipid clinic

We recruited nondiabetic subjects (n = 158) attending a lipid disorders clinic, a subset of whom (n = 46) had established cardiovascular disease. Glycine betaine, N,N-dimethylglycine, and carnitine were measured in fasting plasma and urine samples. The concentrations and excretions were related to known cardiovascular risk factors in multivariate regression models. The relationships between homocysteine and plasma and urinary glycine betaine were highly significant (P < .002), comparable with the known relationships with folate and plasma creatinine. The regression coefficient for plasma glycine betaine was consistently approximately -0.1 in 5 different regression models (3 best-subsets and forward and backward stepwise regression models) for predicting homocysteine using 23 variables. Plasma glycine betaine was higher in males than in females, and the difference was associated with a difference in percentage of body fat. Its concentration included a constant factor of approximately 20 micromol/L that was independent of any of the variables investigated here. In the total group, body fat, homocysteine, and carnitine were significant predictors of plasma glycine betaine. Carnitine, an important betaine that is involved in lipid metabolism positively correlated with both homocysteine and glycine betaine. In our sample, the urinary excretion of glycine betaine was outside the reference range in 14 of the 158 subjects and the betaine fractional clearances were above the reference range in 23 subjects. Fractional clearance correlated strongly with plasma homocysteine (r = 0.50), and this relationship may be stronger in patients with known vascular disease. Urinary loss of glycine betaine may contribute to hyperhomocysteinemia and the development of cardiovascular disease.

Genetic screening of patients with familial hypercholesterolaemia (FH): a New Zealand perspective

Using denaturing high performance liquid chromatography (DHPLC) to screen the LDL receptor gene of people with familial hypercholesterolaemia (FH) in Christchurch, New Zealand, we have identified mutations in 65 patients (44 different mutations, of which 15 are novel). We also test family members of probands for the mutation identified in their relative, allowing diagnosis of affected children and those without classical FH symptoms. This screening programme is helpful to clinicians and benefits FH patients and their families, and has provided us with a pool of LDL receptor variants on which to base research into this disease.

The postprandial state does not impair endothelial function in women with type 2 diabetes irrespective of glycaemic control

AIMS/HYPOTHESIS

The postprandial state has been shown to be associated with endothelial dysfunction, a predictor of cardiovascular morbidity. In type 2 diabetes, postprandial metabolic excursions are prolonged and exaggerated, but less pronounced if glycaemic control is optimised. We investigated the impact of improved glycaemic control on endothelial function in the postprandial state.

METHODS

We studied 19 postmenopausal women with type 2 diabetes and ten non-diabetic subjects. Participants with diabetes were re-studied 3 months after intensive glucose regulation. We measured forearm blood flow by strain gauge plethysmography during rest, during acetylcholine infusion and post ischaemia in the fasting state, and again 3 hours after a mixed meal (660 kcal, 55% fat).

RESULTS

Endothelium-dependent vasodilation was impaired in the diabetic group (p<0.005) and improved following an HbA1c reduction of 0.96% (p<0.05 for high-dose acetylcholine infusion). Postprandial metabolic excursions were higher in the diabetic group (p<0.001, p<0.01 and p<0.05 for glucose, insulin and triglycerides respectively). Resting forearm blood flow increased in all groups after the meal (p<0.005). There was no difference in fasting and postprandial endothelium-dependent vasodilation before and after improved glucose regulation in either group.

CONCLUSIONS/INTERPRETATION

The postprandial state does not impair endothelial function in non-diabetic women and does not make pre-existing endothelial dysfunction worse in women with type 2 diabetes, irrespective of glycaemic control.

Plasma sex hormone-binding globulin rather than corticosteroid-binding globulin is a marker of insulin resistance in obese adult males

AIM

Plasma levels of corticosteroid-binding globulin (CBG) and sex hormone-binding globulin (SHBG) may be regulated by insulin. The aim of this study was to test the hypothesis that these steroid-binding proteins are markers of insulin resistance and obesity in adult patients with the metabolic syndrome.

METHODS

Fasting blood samples were obtained from 108 male and 88 female overweight adult patients who had varying degrees of dyslipidaemia, adiposity and insulin resistance. We measured plasma levels of SHBG and CBG and investigated their correlation with insulin resistance [homeostasis model assessment (HOMA) % sensitivity] and anthropometric markers of adiposity.

RESULTS

In male patients, plasma SHBG correlated positively with HOMA (% sensitivity) and negatively with anthropometric measurements, including body mass index, waist circumference (cm) and percentage body fat. There was no correlation with CBG and any other parameter in the male patients. The female patients were treated as two groups, those not using oral contraceptives or hormone replacement therapy (n = 67) and those taking steroid medications (n = 21). Female patients using steroid medications had significantly higher SHBG levels but neither group showed any correlation between SHBG, insulin resistance and adiposity. Correlation studies of CBG with other parameters in the female subgroups did not reach statistical significance.

CONCLUSIONS

We conclude that plasma SHBG is another surrogate marker for insulin resistance in obese males but not in obese females. It also appears that plasma CBG is not a useful marker of insulin resistance in patients with the metabolic syndrome.

Prospective audit of conversion from regular to lispro insulin during routine clinical care

BACKGROUND

Randomized controlled trials show that lispro insulin has the potential to improve glycaemic control. Observational, practice-based studies provide information that is complementary to that obtained from randomized controlled trials and results of both types of studies are of relevance when advising patients of likely outcomes during routine clinical care.

AIMS

This prospective audit aimed to determine whether conversion from regular (short-acting, soluble) preprandial insulin to lispro during routine clinical care improved glycated haemoglobin.

METHODS

Eligible patients were those using regular insulin before main meals and a basal neutral protamine Hagedorn (NPH) insulin. Study group patients were those who chose to convert to lispro insulin. Patients who elected not to change their regimen were used as a comparison group. Follow up was for a minimum of 1 year.

RESULTS

Glycated haemoglobin (HbA(1c)) and body mass index showed no change in either the study or comparison groups. Post-hoc analysis revealed that the patients most likely to improve their HbA(1c) on lispro were those with a higher baseline HbA(1c). Patients using lispro reported a decreased frequency of hypoglycaemia and improved convenience of use.

CONCLUSIONS

Administration of lispro insulin was perceived by patients as convenient to use and was also associated with less hypoglycaemia when compared with the use of regular insulin. There was, however, no improvement in HbA(1c). This finding may be informative when advising patients during routine clinical care of the likely metabolic outcome of changing their insulin regimen.

Differential effects of simvastatin and atorvastatin on high-density lipoprotein cholesterol and apolipoprotein A-I are consistent across hypercholesterolemic patient subgroups

BACKGROUND

In addition to lowering plasma levels of low-density lipoprotein cholesterol (LDL-C), statins also raise high-density lipoprotein cholesterol (HDL-C).

HYPOTHESIS

Recent studies have shown that treatment with simvastatin results in larger increases in HDL-C than those seen with atorvastatin. The results of three clinical studies are analyzed, comparing the effects of simvastatin and atorvastatin on HDL-C and apolipoprotein A-I (apo A-I) in the total cohort and in several subgroups of hypercholesterolemic patients. The three studies were all multicenter, randomized clinical trials that included simvastatin (20-80 mg) and atorvastatin (10-80 mg) treatment arms. The subgroup analyses performed were gender; age (< 65 and > or = 65 years); baseline HDL-C (male: < 40 or > or = 40 mg/dl; female: < 45 or > or = 45 mg/dl), baseline LDL-C (< 160 or > or = 160 mg/dl), and baseline triglycerides (< 200 or > or = 200 mg/dl).

RESULTS

Both drugs produced similar increases in HDL-C levels at low doses; however, at higher drug doses (40 and 80 mg), HDL-C showed a significantly greater increase with simvastatin than with atorvastatin (p < 0.05 to < 0.001). Therefore, while HDL-C remained consistently elevated across all doses of simvastatin, there appeared to be a pattern of decreasing HDL-C with an increasing dose of atorvastatin. A similar negative dose response pattern was also observed with apo A-I in atorvastatin-treated patients, suggesting a reduction in the number of circulating HDL particles at higher doses. Both drugs reduced LDL-C and triglycerides in a dose-dependent fashion, with atorvastatin showing slightly greater effects. The differential effects of atorvastatin and simvastatin on HDL-C and apo A-I were observed for both the whole study cohorts and all subgroups examined; thus, no consistent treatment-by-subgroup interactions were observed.

CONCLUSION

The data presented show that, across different hypercholesterolemic patient subgroups, simvastatin increases HDL-C and apo A-I more than atorvastatin at higher doses, with evidence of a negative dose response effect on HDL-C and apo A-I with atorvastatin, but not simvastatin.

The deleted in colorectal carcinoma (DCC) gene 201 R → G polymorphism: no evidence for genetic association with autoimmune disease

The product of the deleted in colorectal carcinoma (DCC) gene has a role in apoptosis and is a positional candidate for IDDM6, the putative chromosome 18q12-q23 autoimmune disease locus. We hypothesised that a nonconservative substitution (DCC 201 R --> G; nucleotide (nt) 601 C --> G), located in an extracellular immunoglobulin-like domain of DCC, is an aetiological determinant of autoimmunity. We tested this hypothesis by genetically testing the nt 601 C --> G polymorphism for association with three autoimmune phenotypes in a large population-based case-control study. There was no evidence for association of DCC nt 601 C --> G with autoimmune disease in cohorts comprising 2253 subjects with rheumatoid arthritis, type I diabetes and Graves' disease, and 2225 control subjects, from New Zealand and the United Kingdom. Furthermore, using the transmission disequilibrium test, there was no significant evidence for biased transmission of the nt 601 C --> G polymorphism to probands within a 382 family type I diabetes affected sibpair cohort from the United Kingdom. Thus, the DCC 201 R --> G polymorphism does not appreciably influence risk of developing the autoimmune diseases tested.

Plasma adiponectin in overweight, nondiabetic individuals with or without insulin resistance

AIM

Adiponectin is a protein produced exclusively by adipocytes with putative insulin-sensitizing and anti-atherogenic properties. This cross-sectional study investigated the relationship between plasma adiponectin and a range of anthropometric, glycaemic, lipid and inflammatory parameters in overweight and obese subjects expressing characteristics of the metabolic syndrome.

METHODS

Subjects were selected for the study from a clinical database, if they were non-diabetic, overweight [body mass index (BMI) > 25] and had features of the metabolic syndrome. The subjects were grouped according to BMI (25-30, 31-35 and >35 kg/m2) and then stratified for insulin resistance [homeostasis model assessment (HOMA) %S]. One hundred and ninety-seven patients (109 males and 88 females) were selected for the study by taking an equal number with the highest and lowest HOMA indices from each of the three BMI groups. Plasma adiponectin concentration was measured in duplicate by radioimmunoassay, and the relationship between these levels and the other parameters was investigated using correlation and multiple linear regression analyses.

RESULTS

Plasma adiponectin concentration was higher in females than males (median 10.3 vs. 7.1 micro g/ml, p < 0.001) despite being matched for BMI. In both genders, adiponectin levels were inversely related to BMI, waist circumference, percentage body fat, insulin resistance and the fasting plasma concentration of leptin. A direct correlation in both sexes was found between adiponectin levels and high-density lipoprotein (HDL)-cholesterol, apolipoprotein A1 and age. Multiple linear regression analyses showed that the independent determinants of low plasma adiponectin concentrations were gender, age, BMI, insulin resistance and HDL-cholesterol. An association between reduced adiponectin and increased high-sensitivity plasma C-reactive protein concentration was observed only in female subjects and was independent of anthropometric variables. Our observation that adiponectin levels increase with age differs from the majority of other studies and may simply reflect the demographics of the population studied.

CONCLUSIONS

This study shows that adiponectin is an important molecular link between obesity, insulin resistance and atherogenic lipoproteins. It is possible that plasma adiponectin concentration may be a convenient marker for identifying subjects with the metabolic syndrome who may progress to impaired glucose tolerance. Longitudinal studies are required in order to verify this clinical application of adiponectin.

Cause-specific and total mortality in the Canterbury (New Zealand) insulin-treated Diabetic Registry population: a 15-year follow-up study

AIMS

To establish all-cause and cause-specific death rates, and risk factors for mortality in insulin-treated diabetic individuals living in the province of Canterbury, New Zealand.

METHODS

Insulin-treated diabetic subjects (n = 995) on the Canterbury Diabetes Registry were followed up over 15 years and vital status determined. Death rates were standardized and hazard regression was used to model the effects of demographic covariates on relative survival time.

RESULTS

There were 419 deaths in 11 226.3 person-years of follow-up with a standardized mortality ratio (SMR) of 2.0 (95% confidence interval (CI) 1.8-2.2). Relative mortality was greatest for the group aged 0-29 years (SMR 3.0 (95% CI 2.4-3.7)). After controlling for diabetes duration and gender, a 10-year increment in age of onset was associated with a 33% decrease in relative hazard (95% CI 29-36%), indicating that excess mortality due to diabetes declines with rising age of onset. After controlling for age of onset and gender, each 10-year increment in duration of diabetes is associated with a 26% decrease in relative hazard (95% CI 24-29%), indicating that with longer survival the mortality hazard approaches the general population hazard. Relative mortalities were increased for cardiovascular, renal and respiratory disease, but not malignancy. Relative mortality from acute metabolic complications was increased in the subgroup with age of onset of diabetes < 30 years and requiring insulin within 1 year of diagnosis.

CONCLUSIONS

Mortality rates are high for insulin-treated diabetic individuals relative to the general population.