Cardiomyopathy and cardiovascular events by gender in a comprehensive Finnish patient population with Fabry disease

Background/Introduction

Fabry disease (FD) is a lysosomal storage disorder caused by mutations in the α- galactosidase A gene (GLA) leading to lack of an active GLA enzyme and accumulation of glycosphingolipids in different organs, including heart. Because of X-linked inheritance, the phenotype is usually more severe in males than in females.

Purpose

There are very few national studies on FD. Our aim was to investigate the genetics, phenotype, treatment and prognosis of Finnish Fabry patients by gender.

Methods

Finnish Fabry Registry includes 98 patients, approximately 90% of all Finnish patients with FD, diagnosed from 1972 to 2018. Cardiovascular, neurological and renal events, and cardiac imaging data were recorded from medical charts until 2020. Cardiac ultrasound and MRI (CMR) were performed in 86% and 77% of females and 88% and 78% of males, respectively.

Results

Altogether, 24 different pathogenic GLA mutations were found in 66 females and 32 males from 27 Finnish families. FD, or the causative mutation, was diagnosed at an average age of 41 years in females, and at 29 years in males. During the mean 17 years of follow-up, either ERT or migalastat was started for 58% of females and 88% of males.

At the end of the follow-up, Fabry cardiomyopathy (FCM; maximal left ventricular wall thickness (LVMWT) 13 mm or more in cardiac imagining) had been diagnosed in 47% of females and 66% of males at the mean age of 55 years and 41 years, respectively. Atrial fibrillation (AF) was diagnosed in 21% of females and 9% of males. Heart failure (HF) due to FCM was diagnosed in 20% of females and in 12% of males at the mean age of 62 and 54 years, respectively. A bradycardia pacemaker was required for 9 females and for 2 males and one female and one male had also implantable cardioverter defibrillator. Over 20% of both female and male FD patients suffered a stroke during the follow-up. End-stage kidney disease was not found in females, but 9% of males received a renal transplantation.

During the follow-up 5 females and 3 males died. The mean age at death was 77 years in females, and 48 years in males. All deceased males and 40% of females had been treated with ERT from an average age of 40 and 66 years, respectively. All deceased subjects had FCM. All females and one male died of FD. Two females died of a stroke and three of HF. All deceased males had severe classical FD phenotype. One male suffering from severe HF died of a stroke. One male with an ICD and renal transplant, died of malignancy. The third male withdrew from follow-up and died of gastrointestinal bleeding.

Conclusions

In Finnish patients with FD, cardiomyopathy, related arrhythmias and heart failure were common in both genders. All eight deceased subjects had Fabry cardiomyopathy, and the immediate cause of death was most often heart failure or stroke.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Finnish Heart Research Foundationand Sanofi Genzyme

Prevalence, genotype and phenotype of familial hypercholesterolemia in 10,194 Finnish men

Background

Familial hypercholesterolemia (FH) is the most frequent monogenic disease with an estimated prevalence of 1:250. The prevalence of different variants varies widely between the populations. According to previous studies, the prevalence of heterozygous FH in Finland has been reported to be 1:400–650, seven Finnish LDLR founder mutations having been considered to cause 80% of FH.

Purpose

To investigate the genetics of FH in the large Finnish population-based study.

Methods

The whole exome sequencing using Next Generation Sequencing method was performed for 10,194 men from eastern Finland who participated in the METSIM (Metabolic Syndrome in Men) study. The findings were confirmed by Sanger sequencing. The coding regions of the FH causing genes LDLR, APOB and PCSK9 were sequenced. The pathogenicity of the variants was classified according to the ACMG guidelines, and using the Genome Aggregation Database (gnomAD), and the ClinVar archive.

Results

Total 22 individuals of 10,194 carry 8 different pathogenic/likely pathogenic (P/LP) FH variants (7 LDLR variants, 1 APOB variant and 0 PCK9 variants). Seven LDLR gene variants classified as P/LP were detected in 21 individuals. Two of the seven variants are founder mutations (p.Pro309Lysfs*59, p.Arg595Gln), four are other previously reported variants (p.Arg124Trp, p.Glu228*, p.Asp266Asn, p.Asp445Glu) and one is a novel variant (p.Gly396Ala). Of the 21 individuals carrying P/LP LDLR variants, 16 carry founder mutations and five other P/LP LDLR variants. Of individuals carrying any P/LP LDLR variant, 28.6% had premature (men <55 years, women <60 years) atherosclerotic cardiovascular disease (CVD): coronary artery disease (CAD) 28.6%, peripheral artery disease (PAD) 0.0%, and stroke or TIA 0.0%. CVD at any age was diagnosed in 38.1% (CAD 33.3%, PAD 4.8%, stroke or TIA 9.5%). Only one individual from 10,194 carry APOB variant which is classified as P/LP. The detected APOB variant is a previously reported variant (p.Gln4494del). None of the 10,194 individuals carry P/LP PCSK9 variants. Thus, the prevalence of P/LP FH variants in the population from eastern Finland was 0.22%, 1 in 463.4 (LDLR variants 0.21%, 1 in 485; APOB variants 0.01%, 1 in 10 194). Of the P/LP variant carriers, 72.7% carry founder mutation of the LDLR, and 27.3% carry other LDLR and APOB variants.

Conclusions

The prevalence of heterozygous FH in the population-based study of 10,194 men from eastern Finland was 1 in 463.4, which is about the same as previously reported. LDLR variants accounted for the majority of FH cases, and although previously reported Finnish LDLR founder mutations were common, about 30% of the mutations detected were other LDLR and APOB variants. Pathogenic/likely pathogenic APOB variants were, however, rare and PCSK9 variants were not found.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Kuopio university hospital

Magnetic resonance imaging derived cardiac first pass perfusion in cryptogenic ischemic stroke in the young

Funding Acknowledgements

Type of funding sources: None.

Introduction

Up to 50% of ischemic strokes in adults aged between 18 and 50 are cryptogenic by nature. Heart has been a hypothesised source.

Purpose: Purpose of the study was to investigate the wash in and wash out of gadolinium based contrast agent in the left atrial appendage, and cardiac chambers in first pass cardiac magnetic resonance imaging.

Methods

The study comprised 30 patients with first-ever cryptogenic ischemic stroke and 30 age and gender matched stroke-free controls included in the prospective multicenter study Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Etiology, Triggers and Outcome (SECRETO; NCT01934725). Cardiac magnetic resonance imaging was performed on all participants with a 1.5T magnetic resonance system. Dynamic contrast enhanced T1 weighted first pass perfusion images were acquired in the superior vena cava, the left atrial appendage (Fig. 1), and the left ventricle. The images were analyzed for time-intensity curves (Fig. 2), and results were normalised to individual heart rate. Arrival times, peak times, areas under the curves, relative blood flows (defined as area under the curve/full width at half maximum), and maximum and minimum rates of bolus wash in / wash out were calculated.

Results

The wash in of the contrast agent bolus was similar in patients and controls. Arrival times and peak timings showed similar characteristics in patients and controls in the left atrial appendage (arrival time: 12.4 [2.3] vs. 13.5 [3.6] cardiac cycles, p = 0.657; peak time: 19.6 [5.1] vs. 19.8 [6.9] cardiac cycles, p = 0.929) and the left atrium (arrival time: 12.2 [2.8] vs. 13.0 [3.6] cardiac cycles, p = 0.535; peak time: 18.7 [5.5] vs. 18.1 [5.2] cardiac cycles, p = 0.790). Areas under under the curves and relative blood flows were similar in patients and controls. A significant difference between patients and controls was found in the wash out rate of gadolinium in the left ventricle (-28 [11] vs. -36 [13] 1/cardiac cycles, p = 0.012), indicating slightly slower wash out in the patients.

Conclusions

Cryptogenic ischemic stroke in the young is not associated with prolonged blood flow in the left atrial appendage or left atrium. There were no significant differences in the first pass perfusion between subjects and healthy controls. However, there might be a slight tendency for stagnation of blood flow in the left ventricles of cryptogenic stroke patients.

Left ventricular septal convexity in differentiating hypertrophic cardiomyopathy from hypertensive heart disease – cardiac MRI study

Background

Subjects with hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD) have left ventricular hypertrophy (LVH). It is a common clinical problem to distinguish HCM from HHD. Septal convexity (SC) into the left ventricle is increased in subjects with hypertrophic cardiomyopathy (HCM)-causing mutations with and without LVH.

Purpose

Our objective was to study if SC by cardiac magnetic resonance (CMR) differentiates between HCM and HHD.

Methods

We measured SC in 29 subjects with hypertension and LVH (left ventricular maximal wall thickness (LVMWT) ≥13 mm), in 49 subjects with HCM (LVMWT ≥13 mm) caused by the D175N mutation in the alpha-tropomyosin (TPM1) or the Q1061X mutation in the myosin binding protein C (MYBPC3) genes, and in 20 healthy controls with no LVH. SC into the LV was measured in end-diastolic 4-chamber images as the maximal distance between LV septal endocardial border and a line connecting septal mid-wall points at the level of tricuspid valve insertion and at the level of apical right ventricular insertion on the LV.

Results

Subjects with HCM had significantly increased septal convexity compared to subjects with HHD both in non-indexed and in BSA-indexed measurements (10.7±4.0 mm vs 4.9±2.7 mm, P<0.001 and 5.5±2.1 mm/m2 vs 2.4±1.3 mm/m2, P<0.001). To differentiate between HCM and HHD, septal convexity cutoff value of 7.85 mm performed best with sensitivity of 77% and specificity of 90%. BSA-indexed SC cutoff value of 3.68 mm differentiated between HCM and HHD with sensitivity of 81% and specificity of 86%.

Conclusions

CMR derived septal convexity is easily measured and is useful in discriminating between HCM caused by sarcomere mutations versus HHD.

Measurement of septal convexity

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Finnish Foundation of Cardiovascular Research, the special governmental subsidy for health sciences research of the University Hospital of Kuopio

P4663Hyperinsulinemia, hypertension and two clusters of biomarkers predict aortic stenosis in 10,144 Finnish men

Purpose

To investigate a large panel of biomarkers as predictors of AS in the population-based METSIM cohort.

Methods

Anthropometric, metabolic and inflammatory biomarkers were measured at baseline in the cohort of 10,197 Finnish men. Subjects with AS at baseline (n=53) were excluded from the analyses. Cases of AS were identified from the medical records. Cox regression analysis was used to identify variables predicting AS. Principal components analysis was applied to investigate clustering of variables predicting AS. Uni- and multivariate logistic regression analysis were used to investigate the clusters of biomarkers as predictors of AS.

Results

Over a mean follow-up time of 10.8 years, incident AS was diagnosed in 116 (1.1%) men. In Cox regression analysis, fasting plasma insulin (9.8±12.8 in men without AS vs. 14.5±18.2 mU/l in men with incident AS; P=6.13 x 10–6) and systolic blood pressure (138.2±16.7 vs. 146.3±19.4 mmHg; P=3.8 x 10–7) were associated with higher risk of AS (HR 1.44 (95% CI 1.23–1.68); P=4.04 x 10–5 and HR 1.54 (1.30–1.83); P=3.01 x 10–7, respectively). Other biomarkers, which significantly predicted AS were age, body mass index, waist, waist/hip ratio, body fat mass percentage, urine albumin, CRP, blood GHbA1C, fasting plasma glucose and proinsulin, oral glucose tolerance test (OGTT) 30 min plasma insulin and proinsulin, OGTT 120 min plasma insulin and proinsulin, and serum C-peptide. Glucose tolerance (ADA 2003), and insulin resistance and insulin secretion indices based on HOMA were significant predictors of AS. After adjusting for age, the same biomarkers except for OGTT 120 min plasma proinsulin, blood GHbA1C and fasting plasma glucose significantly predicted AS. After exclusion of diabetic subjects, all biomarkers mentioned above except for GHbA1C, fasting plasma glucose and glucose tolerance predicted AS in unadjusted Cox models. Two clusters of risk factors were found in principal components analysis, one consisting of fasting plasma insulin, HOMA insulin resistance index, waist/hip ratio, GHbA1c and CRP, and another consisting of age, systolic blood pressure and urine albumin, explaining 38.33 and 15.37% of the total variance, respectively. In univariate logistic regression analysis both clusters predicted AS (HR 1.35 (1.15–1.59); P=2.47 x 10–4 and HR 1.73 (1.46–2.04); P=1.53 x 10–10, respectively), and were statistically significant when entered in the multivariate model (HR 1.30 (1.11–1.52); P=1.01 x 10–3 and HR 1.69 (1.43–1.99); P=5.84 x 10–10, respectively).

Conclusion

In the present large-scale population-based study, several biomarkers, particularly hyperinsulinemia and systolic blood pressure, predicted AS. In addition, two clusters of biomarkers, one with high loading on insulin and another on systolic blood pressure, independently predicted AS.

Acknowledgement/Funding

Kuopio University Hospital ja Academy of Finland

Family history of type 2 diabetes increases the risk of both obesity and its complications: is type 2 diabetes a disease of inappropriate lipid storage?

OBJECTIVES

The aim of this study was to characterize diabetes risk in relation to amount and distribution of body fat (environmental factors) and genetic risk defined as having first-degree (FH1) or second-degree relatives with diabetes.

DESIGN

We analysed the METSIM population of 10 197 middle-aged, randomly selected men. At baseline, information about family history of diabetes was registered and all individuals underwent extensive phenotyping. A follow-up study was conducted after 6 years. The metabolic consequences of increased visceral versus subcutaneous fat were characterized in a separate cohort of 158 healthy men (the Kuopio Cohort of the EUGENE2 study).

RESULTS

At baseline, individuals with a family history of diabetes (FH+) had approximately a twofold increase in the prevalence of type 2 diabetes compared with individuals without a family history of the disease (FH-) (18.0% vs. 9.9%; P = 1.3 × 10(-31) ). FH1 individuals were more commonly overweight and obese compared with FH- (69.2% vs. 64.8%; P = 1.3 × 10(-4) ) and, for a given body mass index, showed an increased risk profile for both type 2 diabetes and cardiovascular disease as well as a greater susceptibility to the negative consequences of increased body fat also when nonobese. Subgroup analyses indicated that the metabolic consequences were due primarily to increased ectopic/visceral fat rather than subcutaneous fat. The increased risk profile in FH+ individuals was not altered by adjusting for 43 major diabetes risk genes.

CONCLUSIONS

Family history of type 2 diabetes (particularly FH1) is associated with both increased risk of becoming overweight/obese and with a greater susceptibility to the negative consequences of increasing body fat, probably as a consequence of an increased propensity to accumulate ectopic (nonsubcutaneous) fat.

Associations of erythrocyte membrane fatty acids with the concentrations of C-reactive protein, interleukin 1 receptor antagonist and adiponectin in 1373 men

Dietary and endogenous fatty acids could play a role in low-grade inflammation. In this cross-sectional study the proportions of erythrocyte membrane fatty acids (EMFA) and the concentrations of C-reactive protein (CRP), interleukin-1 receptor antagonist (IL-1Ra) and adiponectin were measured and their confounder-adjusted associations examined in 1373 randomly selected Finnish men aged 45-70 years participating in the population based Metsim study in Eastern Finland. The sum of n-6 EMFAs, without linoleic acid (LA), was positively associated with concentrations of CRP and IL-1Ra (r partial=0.139 and r partial=0.115, P<0.001). These associations were especially strong among lean men (waist circumference <94 cm; r partial=0.156 and r partial=0.189, P<0.001). Total n-3 EMFAs correlated inversely with concentrations of CRP (r partial=-0.098, P<0.001). Palmitoleic acid (16:1n-7) correlated positively with CRP (r partial=0.096, P<0.001). Cis-vaccenic acid (18:1n-7) was associated with high concentrations of adiponectin (r partial=0.139, P<0.001). In conclusion, n-6 EMFAs, except for LA, correlated positively with the inflammatory markers. Palmitoleic acid was associated with CRP, whereas, interestingly, its elongation product, cis-vaccenic acid, associated with anti-inflammatory adiponectin.

Exome sequencing-driven discovery of coding polymorphisms associated with common metabolic phenotypes

AIMS/HYPOTHESIS

Human complex metabolic traits are in part regulated by genetic determinants. Here we applied exome sequencing to identify novel associations of coding polymorphisms at minor allele frequencies (MAFs) >1% with common metabolic phenotypes.

METHODS

The study comprised three stages. We performed medium-depth (8×) whole exome sequencing in 1,000 cases with type 2 diabetes, BMI >27.5 kg/m(2) and hypertension and in 1,000 controls (stage 1). We selected 16,192 polymorphisms nominally associated (p < 0.05) with case-control status, from four selected annotation categories or from loci reported to associate with metabolic traits. These variants were genotyped in 15,989 Danes to search for association with 12 metabolic phenotypes (stage 2). In stage 3, polymorphisms showing potential associations were genotyped in a further 63,896 Europeans.

RESULTS

Exome sequencing identified 70,182 polymorphisms with MAF >1%. In stage 2 we identified 51 potential associations with one or more of eight metabolic phenotypes covered by 45 unique polymorphisms. In meta-analyses of stage 2 and stage 3 results, we demonstrated robust associations for coding polymorphisms in CD300LG (fasting HDL-cholesterol: MAF 3.5%, p = 8.5 × 10(-14)), COBLL1 (type 2 diabetes: MAF 12.5%, OR 0.88, p = 1.2 × 10(-11)) and MACF1 (type 2 diabetes: MAF 23.4%, OR 1.10, p = 8.2 × 10(-10)).

CONCLUSIONS/INTERPRETATION

We applied exome sequencing as a basis for finding genetic determinants of metabolic traits and show the existence of low-frequency and common coding polymorphisms with impact on common metabolic traits. Based on our study, coding polymorphisms with MAF above 1% do not seem to have particularly high effect sizes on the measured metabolic traits.

Lipoprotein subclass profiles in individuals with varying degrees of glucose tolerance: a population-based study of 9399 Finnish men

OBJECTIVES

We investigated serum concentrations of lipoprotein subclass particles and their lipid components determined by proton nuclear magnetic resonance spectroscopy in a population-based study.

DESIGN AND METHODS

A total of 9399 Finnish men were included in the study: 3034 men with normal fasting glucose and normal glucose tolerance; 4345 with isolated impaired fasting glucose (IFG); 312 with isolated impaired glucose tolerance (IGT); 1058 with both IFG and IGT; and 650 with newly diagnosed type 2 diabetes (New DM). Lipoprotein subclasses included chylomicrons (CM) and largest VLDL particles, other VLDL particles (five subclasses), intermediate-density lipoprotein (IDL), LDL (three subclasses) and HDL (four subclasses). The phospholipid, triglyceride (TG), cholesterol, free cholesterol and cholesterol ester levels of the lipoprotein particles were measured.

RESULTS

Abnormal glucose tolerance (especially IGT and New DM) was significantly associated with increased concentrations of VLDL subclass particles and their components (with the exception of very small VLDL particles). After further adjustment for total TGs and HDL cholesterol, increased lipid concentrations in the CM/largest VLDL particles and in most of the other VLDL particles remained significant in individuals with isolated IGT, IFG+IGT and New DM. There was a consistent trend towards a decrease in large and an increase in small HDL particle concentrations in individuals with hyperglycaemia even after adjustment for serum total TGs and HDL cholesterol.

CONCLUSIONS

Abnormal glucose tolerance modifies the concentrations of lipoprotein subclass particles and their lipid components in the circulation and is also related to compositional changes in these particles.

Association between liver insulin resistance and cardiovascular risk factors

OBJECTIVES

The objective of this study was to examine the associations between indices of liver insulin resistance (IR) and whole-body insulin sensitivity and different cardiovascular disease (CVD) risk factors.

DESIGN AND SUBJECTS

A total of 8750 nondiabetic men (age 57.2 ± 7.1 years, body mass index 26.8 ± 3.8 kg m(-2) ) were included in this study from the population-based cross-sectional Metabolic Syndrome In Men (METSIM) cohort. Liver IR index and Matsuda insulin sensitivity index (ISI) were used as markers of liver IR and whole-body insulin sensitivity, respectively. Pearson correlation analysis was performed to examine the associations between these indices and various CVD risk factors.

RESULTS

Total cholesterol (r = -0.088 vs. r = 0.020; P < 0.0019), high-sensitivity C-reactive protein (CRP) (r = 0.284 vs. r = -0.219; P < 0.0019) and total triglycerides (r = 0.507 vs. r = -0.477; P < 0.05) were more highly correlated with liver IR index than with Matsuda ISI. By contrast, Matsuda ISI was nominally more highly correlated with systolic and diastolic blood pressure (r = -0.234 and r = -0.275 vs. r = 0.202 and r = 0.239, respectively) compared to liver IR index. Furthermore, the variance explained by liver IR index was larger than that explained by Matsuda ISI for the majority of CVD risk factors measured.

CONCLUSIONS

Liver IR index correlated more strongly than Matsuda ISI with levels of total cholesterol, CRP and triglycerides. Therefore, liver IR might be a significant indicator of CVD risk amongst men.

Glomerular filtration rate and parathyroid hormone are associated with 1,25-dihydroxyvitamin D in men without chronic kidney disease

BACKGROUND AND AIM

Vitamin D, estimated glomerular filtration rate (eGFR) and parathyroid hormone (PTH) are related to cardiovascular disease risk. We examined the associations between the levels of 25-hydroxyvitamin D (25-D) and 1,25-dihydroxyvitamin D (1,25-D) and both eGFR and PTH.

DESIGN AND SETTING

Cross-sectional population-based study in Kuopio, Eastern Finland.

SUBJECTS

A total of 909 men without known chronic kidney disease (CKD) and not receiving antidiabetic medication, aged from 45 to 73 years, were included in the study. Main outcome measures. Fasting levels of 25-D, 1,25-D, creatinine and PTH were measured, and an oral glucose tolerance test (OGTT) was performed.

RESULTS

High levels of 25-D were associated with low levels of eGFR and PTH (β = -0.17, P = 9 × 10(-7) and β = -0.28, P = 6 × 10(-17) , respectively, adjusted for age, body mass index and levels of calcium, phosphorus and glucose in a 2-h OGTT, and also for either eGFR or PTH). By contrast, high 1,25-D levels were associated with high levels of eGFR and PTH (β = 0.17, P = 2 × 10(-6) and β = 0.19, P = 5 × 10(-8) , respectively, adjusted as mentioned earlier and additionally for 25-D). Eighteen per cent of men in the highest 25-D quartile were in the lowest 1,25-D quartile and also had a lower eGFR than men with high levels of both 25-D and 1,25-D (P = 4 × 10(-5) ). Finally, 15% of men in the lowest 25-D quartile were in the highest 1,25-D quartile and also had higher PTH levels than men with low levels of both 25-D and 1,25-D (P = 2 × 10(-3) ).

CONCLUSION

Our findings suggest that both eGFR and PTH are significantly associated with vitamin D metabolism in men without known CKD.

Association of the FTO gene variant (rs9939609) with cardiovascular disease in men with abnormal glucose metabolism--the Finnish Diabetes Prevention Study

BACKGROUND AND AIM

The common single nucleotide polymorphism (SNP) in the FTO (fat mass and obesity associated) gene has been consistently associated with an increased risk of obesity. We investigated whether the SNP rs9939609 (T/A) of the FTO is associated with risk factors of cardiovascular diseases (CVD), including serum levels of C - reactive protein (CRP), the chemokine RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted; CCL5), and serum and lipoprotein lipids in the Finnish Diabetes Prevention Study (DPS). Furthermore, we examined whether the rs9939609 increased the CVD risk in the DPS and if these results could be replicated in a larger cross-sectional population-based random sample of Finnish men (the METSIM).

METHODS AND RESULTS

In the DPS, altogether 490 (BMI≥25kg/m(2)) subjects with impaired glucose tolerance were genotyped for rs9939609. Cardiovascular morbidity and mortality data were collected during the median follow-up of 10.2 years. The replication study was a population-based cross-sectional study of 6214 men. In the DPS, the AA genotype of rs9939609 was associated, independently of BMI, with increased RANTES (p=0.002) and decreased HDL cholesterol concentrations (p=0.007) in men. During the follow-up, the AA genotype was associated with an adjusted 2.09-fold risk (95% CI 1.17-3.73, p=0.013) of CVD in men. In the METSIM Study, the association with a history of myocardial infarction was replicated in the subgroup of men with type 2 diabetes.

CONCLUSION

We suggest that the variation in the FTO gene may contribute to the development of CVD in men with an abnormal glucose metabolism.

Glucose tolerance, insulin sensitivity and insulin release in European non-diabetic carriers of a polymorphism upstream of CDKN2A and CDKN2B

AIMS/HYPOTHESIS

The aim of this study was to investigate the association of the rs10811661 polymorphism near the CDKN2B/CDKN2A genes with glucose tolerance, insulin sensitivity and insulin release in three samples of white people with European ancestry.

METHODS

Sample 1 comprised 845 non-diabetic offspring of type 2 diabetes patients recruited in five European centres participating in the EUGENE2 study. Samples 2 and 3 comprised, respectively, 864 and 524 Italian non-diabetic participants. All individuals underwent an OGTT. Screening for the rs10811661 polymorphism was performed using a TaqMan allelic discrimination assay.

RESULTS

The rs10811661 polymorphism did not show a significant association with age, BMI and insulin sensitivity. Participants carrying the TT genotype showed a significant reduction in insulin release, measured by an OGTT-derived index, compared with carriers of the C allele, in the three samples. When these results were pooled with those of three published studies, and meta-analysed with a random-effects model, the T allele was significantly associated with reduced insulin secretion (-35.09 [95% CI 14.68-55.52], p = 0.0008 for CC+CT vs TT; and -29.45 [95% CI 9.51-49.38], p = 0.0038, for the additive model). In addition, in our three samples, participants carrying the TT genotype exhibited an increased risk for impaired glucose tolerance (IGT) compared with carriers of the C allele (OR 1.55 [95% CI 1.20-1.95] for the meta-analysis of the three samples).

CONCLUSIONS/INTERPRETATION

Our data, together with the meta-analysis of previously published studies, show that the rs10811661 polymorphism is associated with impaired insulin release and IGT, suggesting that this variant may contribute to type 2 diabetes by affecting beta cell function.

A novel surrogate index for hepatic insulin resistance

AIMS/HYPOTHESIS

In epidemiological and genetic studies surrogate indices are needed to investigate insulin resistance in different insulin-sensitive tissues. Our objective was to develop a surrogate index for hepatic insulin resistance.

METHODS

A sample of 368 non-diabetic participants (age 43.0 ± 8.2 years, BMI 26.0 ± 4.0 kg/m(2); mean ± SD) whose endogenous glucose production (EGP) was measured with [6-6(2)H(2)]glucose in the fasting state and during the euglycaemic-hyperinsulinaemic clamp were included in the study. EGP multiplied by fasting plasma insulin (FPI) concentration was the reference measurement for liver insulin resistance (liver IR). Liver IR index was calculated with linear regression analysis including age, obesity indices, lipids, lipoproteins and several variables regulating glucose metabolism.

RESULTS

The following variables were significantly associated with liver IR in multiple forward stepwise regression analysis: insulin AUC in an OGTT, fat mass, HDL-cholesterol and BMI. Liver IR index correlated significantly with EGP×FPI (r = 0.65, p < 0.001). In participants with abnormal glucose tolerance, the correlation of liver IR with EGP×FPI was slightly stronger (r = 0.69, p < 0.001) than in those with normal glucose tolerance (r = 0.62, p < 0.001).

CONCLUSIONS/INTERPRETATION

We generated a novel surrogate index for liver insulin resistance correlating strongly with EGP × FPI.

Association of indices of liver and adipocyte insulin resistance with 19 confirmed susceptibility loci for type 2 diabetes in 6,733 non-diabetic Finnish men

AIMS/HYPOTHESIS

Of the confirmed type 2 diabetes susceptibility loci only a few are known to affect insulin sensitivity. We examined the association of indices of hepatic and adipocyte insulin resistance (IR) with 19 confirmed type 2 diabetes risk loci in a large population-based study.

METHODS

Non-diabetic participants (n = 8,460, age 57.3 ± 7.0 years, BMI 26.8 ± 3.8 kg/m(2); mean ± SD) from a population-based cohort underwent an OGTT. Of them, 6,733 non-diabetic men were genotyped for single nucleotide polymorphisms (SNPs) in or near PPARG2 (also known as PPARG), KCNJ11, TCF7L2, SLC30A8, HHEX, CDKN2B, IGF2BP2, CDKAL1, HNF1B, WFS1, JAZF1, CDC123, TSPAN8, THADA, ADAMTS9, NOTCH2, KCNQ1, MTNR1B and SNP rs7480010. We investigated hepatic IR with a new index of liver IR. The adipocyte IR index was defined as a product of fasting NEFA and plasma insulin levels.

RESULTS

Type 2 diabetes risk SNPs in or near KCNJ11 and HHEX were significantly (p < 0.0013), and those in or near CDKN2B, NOTCH2 and MTNR1B were nominally (p < 0.05), associated with decreased liver IR index. The Pro12 allele of PPARG2 was significantly associated with a high adipocyte IR index and nominally associated with high liver IR.

CONCLUSIONS/INTERPRETATION

The Pro12 allele of PPARG2 seems to impair insulin's antilipolytic effect, leading to high NEFA release in the fasting state and IR. In addition, the type 2 diabetes risk alleles of KCNJ11 and HHEX, which are known to impair insulin secretion, were associated with increased hepatic insulin sensitivity.

A role for coding functional variants in HNF4A in type 2 diabetes susceptibility

AIMS/HYPOTHESIS

Rare mutations in the gene HNF4A, encoding the transcription factor hepatocyte nuclear factor 4α (HNF-4A), account for ~5% of cases of MODY and more frequent variants in this gene may be involved in multifactorial forms of diabetes. Two low-frequency, non-synonymous variants in HNF4A (V255M, minor allele frequency [MAF] ~0.1%; T130I, MAF ~3.0%)-known to influence downstream HNF-4A target gene expression-are of interest, but previous type 2 diabetes association reports were inconclusive. We aimed to evaluate the contribution of these variants to type 2 diabetes susceptibility through large-scale association analysis.

METHODS

We genotyped both variants in at least 5,745 cases and 14,756 population controls from the UK and Denmark. We also undertook an expanded association analysis that included previously reported and novel genotype data obtained in Danish, Finnish, Canadian and Swedish samples. A meta-analysis incorporating all published association studies of the T130I variant was subsequently carried out in a maximum sample size of 14,279 cases and 26,835 controls.

RESULTS

We found no association between V255M and type 2 diabetes in either the initial (p = 0.28) or the expanded analysis (p = 0.44). However, T130I demonstrated a modest association with type 2 diabetes in the UK and Danish samples (additive per allele OR 1.17 [95% CI 1.08-1.28]; p = 1.5 × 10⁻⁴), which was strengthened in the meta-analysis (OR 1.20 [95% CI 1.10-1.30]; p = 2.1 × 10⁻⁵).

CONCLUSIONS/INTERPRETATION

Our data are consistent with T130I as a low-frequency variant influencing type 2 diabetes risk, but are not conclusive when judged against stringent standards for genome-wide significance. This study exemplifies the difficulties encountered in association testing of low-frequency variants.

Diverse associations of 25-hydroxyvitamin D and 1,25-dihydroxy-vitamin D with dyslipidaemias

BACKGROUND AND AIM

Previous studies have suggested a link between circulating levels of 25-hydroxyvitamin D (25-D) and dyslipidaemias. However, it is not known whether 25-D and the active hormone 1,25-dihydroxyvitamin D (1,25-D) have similar associations with dyslipidaemias. Therefore, we studied the associations between both 25-D and 1,25-D and total cholesterol (total-C), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides in a population-based study.

DESIGN

Cross-sectional population-based study.

SETTING

Kuopio, Eastern Finland.

SUBJECTS

A total of 909 men, aged from 45 to 70 years, who were not receiving antidiabetic medication were enrolled.

MAIN OUTCOME MEASURES

Fasting serum samples were obtained for measurement of 25-D, 1,25-D and lipid levels. An oral glucose tolerance test was performed, and insulin sensitivity was evaluated using the Matsuda insulin sensitivity index (Matsuda ISI).

RESULTS

We found a significant inverse association between 25-D and total-C, LDL-C and triglycerides (β = -0.15, -0.13 and -0.17, respectively, P < 0.001), but no association between 25-D and HDL-C was observed. By contrast, 1,25-D was associated with HDL-C (β = 0.18, P < 0.001), whereas no relationship was found between 1,25-D and LDL-C or triglycerides. The associations remained significant after the exclusion of subjects receiving statin treatment and after adjustment for age, waist circumference, body mass index, alcohol consumption, smoking, renal function, glucose tolerance and Matsuda ISI.

CONCLUSION

Low levels of active vitamin D (1,25-D) are associated with low HDL-C levels, whereas low levels of the storage form 25-D are associated with high levels of total-C, LDL-C and triglycerides. Our findings may provide new insights into the understanding of the link between vitamin D deficiency and cardiovascular disease.

Variants of transcription factor 7-like 2 (TCF7L2) gene predict conversion to type 2 diabetes in the Finnish Diabetes Prevention Study and are associated with impaired glucose regulation and impaired insulin secretion

AIMS/HYPOTHESIS

We investigated the association of variants of the transcription factor 7-like 2 (TCF7L2) gene with: (1) incident diabetes in the Finnish Diabetes Prevention Study (DPS, Study I); (2) type 2 diabetes and impaired glucose regulation (i.e. IGT or IFG) in a cross-sectional study (Study II); and (3) insulin secretion, insulin sensitivity and adipose tissue expression of TCF7L2 in offspring of type 2 diabetic probands (III).

SUBJECTS AND METHODS

Study I (the DPS) included 507 individuals with IGT who were randomly allocated to control and intervention groups and followed for an average of 3.9 years to monitor for progression to diabetes. Study II was a population-based cross-sectional study of 1,766 men, aged 50-70 years, randomly selected from the population of Kuopio, eastern Finland. Study III included 238 non-diabetic offspring of patients with type 2 diabetes. Genotyping of rs12255372 and rs7903146 of TCF7L2 was carried out.

RESULTS

In the DPS, the TT genotype of rs12255372 was significantly associated with an adjusted 2.85-fold risk (95% CI 1.17-6.95, p = 0.021) of incident diabetes in the control group, but not in the intervention group. In Study II, the adjusted odds ratio in subjects with the TT genotype was 3.40 (1.45-7.97, p = 0.005) for the comparison of diabetic subjects with normoglycaemic subjects. The T allele of rs12255372 was significantly associated with decreased insulin secretion (Studies II, III). Expression of TCF7L2 in adipose tissue tended to be lower in subjects with the TT risk genotypes of rs12255372 and rs7903146.

CONCLUSIONS/INTERPRETATION

The variant of rs12255372 of TCF7L2 was associated with incident type 2 diabetes in the DPS and in a separate population-based cross-sectional study. Impaired insulin secretion is likely to be the main cause for our findings.

Association of metabolic syndrome with Alzheimer disease: a population-based study

OBJECTIVE

To assess the association of metabolic syndrome (MetS) with Alzheimer disease (AD).

METHODS

The authors derived subjects from a population-based study of 980 randomly selected elderly subjects. After exclusion of all non-Alzheimer dementia cases, the final study population included 959 subjects (337 men and 622 women) aged 69 to 78 years. The presence of MetS was defined according to the National Cholesterol Education Program (Adult Treatment Panel III) criteria, and the diagnosis of AD was based on the criteria of the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association.

RESULTS

Of the study subjects, 418 (43.6%) had MetS. Probable or possible AD was diagnosed in 45 subjects (4.7%). AD was more frequently detected in subjects with MetS than in subjects without MetS (7.2 vs 2.8%; p < 0.001). The prevalence of AD was higher in women with MetS vs women without the syndrome (8.3 vs 1.9%; p < 0.001), but in men with MetS, the prevalence of AD was not increased (3.8 vs 3.9%; p = 0.994). In univariate logistic regression analysis, MetS was significantly associated with AD (odds ratio [OR] 2.71; 95% CI 1.44 to 5.10). In multivariate logistic regression analysis including also apolipoprotein E4 phenotype, education, age, and total cholesterol, MetS was significantly associated with AD (OR 2.46; 95% CI 1.27 to 4.78). If only nondiabetic subjects were included in the multivariate analysis, MetS was still significantly associated with AD (OR 3.26; 95% CI 1.45 to 7.27).

CONCLUSION

Metabolic syndrome is associated with Alzheimer disease in elderly subjects.

Common polymorphisms of calpain-10 are associated with abdominal obesity in subjects at high risk of type 2 diabetes

AIMS/HYPOTHESIS

The mechanisms by which the calpain-10 gene (CAPN10) affects the risk of type 2 diabetes are unclear. Therefore, we investigated the effects of four polymorphisms in CAPN10 (single nucleotide polymorphism [SNP]-43, SNP-44, Insertion/Deletion [Indel]-19 and SNP-63) on insulin secretion, insulin action and abdominal fat distribution in offspring of patients with type 2 diabetes.

SUBJECTS AND METHODS

Insulin secretion was determined by an IVGTT, insulin action by the hyperinsulinaemic-euglycaemic clamp and abdominal fat distribution by computed tomography in 158 non-diabetic offspring (age 34.9+/-6.3 years [mean+/-SD], BMI 26.2+/-4.9 kg/m(2)) of type 2 diabetic patients.

RESULTS

SNP-43 (p=0.009 over the three genotypes, adjusted for age, sex, BMI and family relationship) and haplotypes carrying the A allele of SNP-43 were associated with intra-abdominal fat area. The A allele of SNP-43 was associated with intra-abdominal fat area in men (p=0.014) but not in women. SNP-44, InDel-19 and SNP-63 were not associated with intra-abdominal fat area or insulin action. Furthermore, we demonstrated in a separate sample of middle-aged men (n=234) who had a history of type 2 diabetes in first-degree relatives that the A allele of SNP-43 was associated with a large waist circumference, and high insulin levels in an OGTT.

CONCLUSIONS/INTERPRETATION

SNP-43 of CAPN10 may contribute to the risk of diabetes by regulating abdominal obesity in subjects with high risk of type 2 diabetes.

Inducibility of life-threatening ventricular arrhythmias is related to maximum left ventricular thickness and clinical markers of sudden cardiac death in patients with hypertrophic cardiomyopathy attributable to the Asp175Asn mutation in the alpha-tropomyosin gene

We investigated inducibility of life-threatening arrhythmias with programmed ventricular stimulation (PVS) in relation to clinical markers of sudden cardiac death (SCD) in subjects with hypertrophic cardiomyopathy (HCM) attributable to the Asp175Asn mutation in the alpha-tropomyosin gene (TPM1-Asp175Asn). PVS was performed with up to three extrastimuli and distribution of markers of SCD was evaluated in 21 adult subjects with the TPM1-Asp175Asn. Sustained polymorphic ventricular tachycardia (VT) or ventricular fibrillation (VF) was induced in seven of 21 subjects (33%). Inducible subjects had more severe left ventricular hypertrophy (LVH) and an increased number of markers of SCD (family history of SCD, syncope or presyncope, fall in systolic blood pressure (BP) during exercise, documented non-sustained VT (NSVT), and marked LVH) compared to non-inducible subjects (IVS 2.4 +/- 0.3 cm vs. 1.6 +/- 0.5 cm, P < 0.001; and two to three vs. one to two markers of SCD, P = 0.007, respectively). In conclusion, in HCM attributable to the Asp175Asn mutation in the alpha-tropomyosin gene, life-threatening arrhythmias were induced in one third of the patients. Inducibility was associated with the maximum left ventricular (LV) thickness and the number of markers of SCD, suggesting that in HCM patients with an identical causative mutation, susceptibility to ventricular arrhythmias is related to the cardiomyopathic phenotype.

Insulin resistance syndrome predicts coronary heart disease events in elderly type 2 diabetic men

OBJECTIVE

To investigate whether cardiovascular risk factors cluster with hyperinsulinemia in elderly type 2 diabetic subjects and, if so, whether this clustering predicts coronary heart disease (CHD) events during a 7-year follow-up.

RESEARCH DESIGN AND METHODS

Clustering of cardiovascular risk factors was analyzed by factor analysis. Cox regression models were used to investigate whether these clusters (factors) predict CHD events (CHD death or nonfatal myocardial infarction) during a 7-year follow-up in 229 type 2 diabetic subjects aged 65-74 years.

RESULTS

There were 70 CHD events (21 in men and 49 in women) during the follow-up period. In diabetic men, components of the insulin resistance syndrome (IRS) loaded on Factor 1 (the insulin resistance factor), which reflected high fasting insulin, obesity (high BMI), central obesity (high waist-to-hip ratio), high total triglycerides, and a short duration of diabetes. Only this IRS factor predicted CHD events in multivariate Cox regression analysis (hazard ratio [HR] 1.71, 95% CI 1.08-2.71, P = 0.022). In diabetic women, components of IRS loaded on two factors, none of which predicted CHD events. In women, only Factor 4, characterized by advanced age, left ventricular hypertrophy on electrocardiogram, high alcohol consumption, high systolic blood pressure, and albuminuria, predicted CHD events in multivariate Cox regression analysis (1.34, 1.03-1.74, P = 0.03).

CONCLUSIONS

IRS is a risk factor for CHD in elderly type 2 diabetic men.

New amino acid substitutions in the IRS-2 gene in Finnish and Chinese subjects with late-onset type 2 diabetes

We investigated the significance of the variants of the IRS-2 gene in patients with type 2 diabetes. The entire coding part of the IRS-2 gene was screened by single-strand conformation polymorphism analysis in 40 Chinese and 40 Finnish patients with late-onset type 2 diabetes. The association of the variants of the IRS-2 gene with type 2 diabetes was studied in 85 Finnish diabetic patients and 82 Finnish control subjects and in 100 Chinese diabetic patients and 85 Chinese control subjects. The four variants predicting structural changes in the insulin receptor substrate (IRS)-2 protein included an insertion of AAC (Asn) in the Asn repeat sequence centered around codons 29-36 (allele frequencies of 0 vs. 0.6% and 1.5 vs. 0%), the Ala157Thr substitution (0 vs. 0% and 0.5 vs. 0%), the Leu647Val substitution (0.6 vs. 0% and 0 vs. 0%), and the Gly1057Asp polymorphism (31 vs. 31% and 35 vs. 30%) (P = NS for all comparisons). Furthermore, six silent variants were observed (CGC147CGG, CCC155CCG, GCC156GCT, AGT723AGC, TGT816TGC, and CCC829CCT). The Gly1057Asp polymorphism was not associated with insulin resistance or impaired insulin secretion in Finnish subjects with normal glucose tolerance (n = 295) or impaired glucose tolerance (n = 38). These data indicate that structural variants of the IRS-2 gene were uncommon in Finnish and Chinese patients with type 2 diabetes. Thus, the variants in the coding part of the IRS-2 gene are unlikely to have a major role in the development of type 2 diabetes in Finnish or Chinese subjects.

APOE-epsilon4 is associated with weight loss in women with AD: a population-based study

OBJECTIVE

To investigate whether the APOE-epsilon4 allele is associated with weight loss in patients with AD or in nondemented elderly subjects.

BACKGROUND

Weight loss has been considered a typical feature of AD. APOE-epsilon4 is a risk factor for AD and was recently proposed to be associated with weight loss in elderly women. It is not known whether APOE-epsilon4 is associated with weight loss in patients with AD or in the general population.

METHODS

Weight and BMI measurements at an average interval of 3.5 years and APOE phenotype determination were performed in an elderly population (n = 980), including 46 patients with AD and 911 control subjects at the end of the follow-up.

RESULTS

On average, patients with AD with the epsilon4 allele lost 1.9 +/- 4.0 kg (BMI 0.8 +/- 1.8 kg/m2) whereas epsilon4 noncarriers gained 1.2 +/- 3.8 kg (BMI 0.4 +/- 1.5 kg/m2) (both p < 0.05), after controlling for diabetes and exercise. However, when men and women were analyzed separately, weight loss was observed only in those women with AD with the epsilon4 allele. Clinically significant weight loss, defined as loss of > or = 5% of body weight, occurred more frequently in both patients with AD (30% versus 6%; p < 0.05) and control subjects (28% versus 18%; p < 0.001) carrying the epsilon4 allele.

CONCLUSIONS

The APOE-epsilon4 allele may contribute to the unexplained weight loss in AD, especially in women.

Apolipoprotein E phenotype alone does not influence survival in Alzheimer's disease: a population-based longitudinal study

Apolipoprotein E4 (ApoE4) phenotype is a known risk factor for development of Alzheimer's disease (AD). Contradictory results exist concerning the role of ApoE4 in the rate of decline and mortality in AD. Conflicting findings have also been reported about ApoE and gender interactions with respect to survival. We examined the survival of subjects with AD and non-AD controls with respect to ApoE phenotype and gender in a population-based longitudinal study. Cognitive evaluation was performed for a total of 980 subjects (then aged 69-78 years), and 48 cases with AD were identified. ApoE4 phenotype was more frequently present among subjects with AD. In the whole study population, survival was not related to the presence of AD or ApoE4 phenotype. Risk of death was increased for men compared to women, independently of the ApoE4 phenotype (HR 0.5, 95% confidence interval 0.44-0.69). In subjects with AD, the presence of ApoE4 alone did not influence survival. However, in the AD group, ApoE4-negative men had significantly increased risk of mortality compared to the risk in ApoE4-negative women (p < 0.01). We conclude that the presence of ApoE4 phenotype or AD did not influence mortality in the aged population. Once AD had become manifest, ApoE4 alone did not relate to survival. However, in subjects with AD not carrying ApoE4, men had reduced survival compared to women.

Gene encoding the catalytic subunit p110beta of human phosphatidylinositol 3-kinase: cloning, genomic structure, and screening for variants in patients with type 2 diabetes

Phosphatidylinositol (PI) 3-kinase is a key signaling molecule in insulin-stimulated glucose transport. Therefore, we investigated the catalytic subunit p110beta, of human PI 3-kinase as a candidate gene for type 2 diabetes. Human p110beta gene was cloned from the placental genomic library. All 22 exons, intronic regions flanking the exons and 1.5 kb of the proximal/5' region of the p110beta gene, were screened for variants by single-strand conformation polymorphism analysis in 79 Finnish patients with type 2 diabetes . Allele frequencies of the variants were also determined in 77 nondiabetic control subjects. No variants were found in exons in diabetic patients. However, we identified two nucleotide polymorphisms in the proximal/5' region of the p110beta gene and a variation in the number of 2-bp repeat sequence (TA)n in intron 4. The allele frequencies did not differ between diabetic and control subjects. Our results may indicate that the catalytic subunit p110beta of PI 3-kinase plays such a fundamental role in the insulin-signaling pathway that structural variants are not likely to exist in that gene. The importance of the polymorphisms in the proximal/5' region of the p110beta gene for insulin signaling remains to be determined.

Variants in the hepatocyte nuclear factor-1alpha and -4alpha genes in Finnish and Chinese subjects with late-onset type 2 diabetes

OBJECTIVE

To determine the role of the hepatocyte nuclear factor (HNF)-1alpha and HNF-4alpha genes in the etiology of late-onset type 2 diabetes in Finnish and Chinese subjects.

RESEARCH DESIGN AND METHODS

The whole coding regions of the genes encoding for HNF-1alpha and HNF-4alpha, including approximately 800 bp of the HNF-1alpha promoter, were investigated in 40 Finnish subjects (fasting C-peptide 50-570 pmol/l) and 47 Chinese subjects with type 2 diabetes by single-strand conformation polymorphism (SSCP) analysis. Frequencies of the variants of these genes were analyzed by restriction fragment-length polymorphism analysis in additional samples of 100 Finnish diabetic patients and 82 Finnish control subjects and in 58 Chinese diabetic patients and 51 Chinese control subjects.

RESULTS

No previously reported gene defects were detected, but one novel functionally silent GCC-->GCG variant (nucleotide 73, exon 10) was observed in the HNF-4alpha gene in a Chinese diabetic patient. Interestingly, the Ala98Val substitution of the HNF-1alpha gene occurred at a significantly higher frequency in 140 Finnish diabetic patients compared with 82 control subjects (P = 0.014). The Ala98Val variant was not, however, associated with abnormalities in insulin secretion evaluated by oral and intravenous glucose tolerance tests in subjects with normal (n = 295) or impaired (n = 38) glucose tolerance.

CONCLUSIONS

Variants in the HNF-1alpha and HNF-4alpha genes are unlikely to play a major role in the pathogenesis of late-onset type 2 diabetes in Finnish and Chinese subjects. However, the association of the Ala98Val variant of the HNF-1alpha gene with type 2 diabetes in Finnish subjects may indicate a diabetogenic locus close to the HNF-1alpha gene.

The Pro12A1a substitution in the peroxisome proliferator activated receptor gamma 2 is associated with an insulin-sensitive phenotype in families with familial combined hyperlipidemia and in nondiabetic elderly subjects with dyslipidemia

Dyslipidemias and insulin resistance often present simultaneously, as in familial combined hyperlipidemia (FCHL), and therefore may have a common genetic background. In our previous study the Pro12A1a substitution of peroxisome proliferator receptor gamma 2 (PPARgamma2) associated with insulin sensitivity, low body mass index (BMI) and high-density lipoprotein (HDL) cholesterol levels. In this study, we investigated the role of this substitution in dyslipidemias. Therefore, 228 nondiabetic members of FCHL families and 866 nondiabetic elderly subjects with (n=217) and without dyslipidemia (n=649) were genotyped. The allele frequencies of the Pro12A1a substitution did not differ between elderly subjects with or without dyslipidemia or 27 probands with FCHL. However, this substitution was associated with low fasting insulin levels both in FCHL family members (P = 0.036 adjusted for gender and age) and elderly subjects with dyslipidemia (P=0.050) but not in elderly subjects without dyslipidemia (P=0.080). In addition, the Ala12 allele of PPARgamma2 was associated with low BMI (P= 0.034) and low total triglycerides (P=0.027), and increased HDL-cholesterol (P < 0.001) in elderly subjects with dyslipidemia (n=299) but not among any other study groups. We conclude that the Ala12 isoform of PPARgamma2 ameliorates the insulin resistance and unfavorable lipid and lipoprotein profiles in FCHL and hyperlipidemic elderly subjects.

Sulfonylurea receptor 1 gene variants are associated with gestational diabetes and type 2 diabetes but not with altered secretion of insulin

OBJECTIVE

To investigate the possible association of the variants in the nucleotide binding fold regions of the sulfonylurea receptor 1 (SUR1) gene with gestational diabetes mellitus (GDM), type 2 diabetes, and altered insulin secretion in Finnish subjects.

RESEARCH DESIGN AND METHODS

The nucleotide binding fold regions of the SUR1 gene were amplified with polymerase chain reaction and screened by the single-strand conformational polymorphism analysis in 42 subjects with GDM and 40 subjects with type 2 diabetes. Detected variants were further investigated in 377 normoglycemic subjects by restriction fragment-length polymorphism analysis. The effect of the variants of the SUR1 gene on first-phase insulin secretion was studied in 295 normoglycemic subjects.

RESULTS

In subjects with GDM or type 2 diabetes, one amino acid change (S1369A), four silent substitutions (R1273R, L829L, T759T, and K649K), and three intron variants were identified in the nucleotide binding fold regions of the SUR1 gene. A tagGCC allele of exon 16 splice acceptor site was more frequent in subjects with GDM (0.55 allele frequency, n = 42) and type 2 diabetes (0.60, n = 40) than in normoglycemic subjects (0.43, n = 377) (P1 = 0.024 and P2 = 0.009, respectively). Similarly, an AGG allele of the R1273R polymorphism was more common in subjects with GDM (0.87) and type 2 diabetes (0.87) than in normoglycemic subjects (0.74) (P1 = 0.009 and P2 = 0.001, respectively). However, the S1369A, R1273R, and cagGCC-->tagGCC variants of the SUR1 gene were not associated with altered first-phase insulin secretion in 295 normoglycemic subjects.

CONCLUSIONS

These results suggest that a functional variant that contributes to the risk of GDM and type 2 diabetes may locate close to the SUR1 gene.

LDL size and risk of coronary heart disease in elderly men and women

A predominance of small, dense, low density lipoprotein (LDL) particles has consistently been associated with coronary heart disease (CHD) in young and middle-aged subjects in cross-sectional studies. Recently, 3 prospective, case-control studies showed that decreased LDL size is a predictor of CHD in middle-aged subjects. However, it is not known whether decreased LDL size is mainly associated with premature CHD or whether it continues to play a role in CHD risk at older ages also. We performed a prospective, nested case-control study in 86 subjects (58 nondiabetic and 28 type 2 diabetic) aged 65 to 74 years who were free of myocardial infarction at baseline and who then had a myocardial infarction or CHD death during a 3.5-year follow-up (cases) and in 172 controls matched for sex and diabetes status but who remained free of CHD during follow-up. LDL particle size determined by gradient gel electrophoresis (268.2+/-0.9 versus 268.5+/-0.7 A, P=0.782) and the proportion of subjects with LDL subclass phenotype B (20.9 versus 21. 5, P=0.914) were similar among cases and controls. Furthermore, diastolic blood pressure, total cholesterol, high density lipoprotein cholesterol, triglycerides, apolipoprotein A(1), fasting glucose, fasting insulin, waist-to-hip ratio, and body mass index were not associated with CHD risk. However, smoking and increased systolic blood pressure, apolipoprotein B levels, and the total cholesterol-high density lipoprotein cholesterol ratio were significant predictors of CHD events both in univariate and multivariate analyses. Our findings indicate that LDL size is not a predictor of CHD events in elderly white subjects after controlling for diabetes status.

The cardiac troponin I gene is not associated with hypertrophic cardiomyopathy in patients from eastern Finland

Defects in seven genes encoding sarcomere proteins have been shown to cause hypertrophic cardiomyopathy. To date, only one study reporting defects in the cardiac troponin I gene associated with hypertrophic cardiomyopathy has been published, and the proportion of hypertrophic cardiomyopathy cases caused by defects in this gene is unknown. Therefore, the authors screened 37 unrelated Finnish patients with hypertrophic cardiomyopathy for variants in the cardiac troponin I gene. Exons 1-8 of the troponin I gene were screened with the polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) method. Five different variants (four intron variants and one silent exon variant) were found. Most variants were also present in control samples and none of the variants co-segregated with the disease in families. The results of the present study indicate that defects in the cardiac troponin I gene do not cause hypertrophic cardiomyopathy in patients from Eastern Finland.

Simultaneous hypertrophic cardiomyopathy and ventricular septal defect in children

Our findings are based on clinical observations and not on a designed study. However, in our University Hospital area, all children with suspected or verified HC are sent to the same pediatric cardiologist (TT). Therefore, our patients are probably representative of children with HC, at least in East Finland. Although the number of patients was small, the prevalence of VSD in children with HC was so high, that it is improbable that the association between the 2 diseases is due to chance alone. Larger studies are needed to confirm our results and to show if muscular VSDs are typical of all HC cases or of specific subgroups only. We suggest that children with HC should undergo a thorough echocardiographic examination to detect possible muscular VSDs, which are usually readily detected by modern color flow mapping techniques. Importantly, in children with a muscular VSD, the possibility of HC as an underlying pathology should be kept in mind.

Type-2 diabetes and cognitive function in a non-demented population

OBJECTIVES

To study if type-2 (non-insulin-dependent) diabetes mellitus (NIDDM) is associated with cognitive dysfunction independently of clinically diagnosed dementia in an elderly population.

MATERIAL AND METHODS

Cognitive function was investigated with a brief neuropsychological test battery in a non-demented elderly population consisting of 183 NIDDM (World Health Organization, 1985) patients and 732 non-diabetic subjects.

RESULTS

Patients with NIDDM were impaired in the Trail-Making Test parts A and C, which may be a reflection of mildly affected frontal lobe/executive functions. Women with NIDDM performed better than non-diabetic subjects in the Mini-Mental State Examination.

CONCLUSIONS

We conclude that NIDDM per se is not associated with impaired memory in the elderly, and the minor defects observed in tests of frontal lobe/executive functions are unlikely to affect daily living. In the non-demented population aged 69 78 years, NIDDM does not carry a significant risk of cognitive dysfunction, when compared to the non-diabetic subjects.

Insulin resistance syndrome predicts coronary heart disease events in elderly nondiabetic men

BACKGROUND

The role of a cluster of risk factors characteristic for the insulin resistance syndrome as a predictor for coronary heart disease (CHD) has not been studied previously.

METHODS AND RESULTS

Clustering of cardiovascular risk factors was analyzed by factor analysis to investigate whether these clusters (factors) predict CHD events (CHD death or nonfatal myocardial infarction) in a nondiabetic population of 1069 subjects 65 to 74 years old from eastern Finland followed up for 7 years. There were 151 CHD events (92 for men, 59 for women) during the follow-up period. In men, factor 1 (the insulin resistance factor, which reflected primarily body mass index, waist-to-hip ratio, triglycerides, fasting plasma glucose, and insulin) (hazards ratio [HR] with 95% CI, 1.33, CI 1.08, 1.65, P=0.008), factor 2 (alcohol consumption, high HDL cholesterol, low triglycerides) (HR 0.78, CI 0.63, 0.96, P=0.020), factor 3 (age, systolic blood pressure, urinary albumin/creatinine ratio, left ventricular hypertrophy) (HR 1.52, CI 1.26, 1.83, P<0.001), and factor 4 (high total cholesterol and triglycerides) (HR 1.42, CI 1. 15, 1.77, P=0.002) predicted CHD events in multivariate Cox regression analysis. In women, the insulin resistance factor did not predict CHD events (HR 1.06, CI 0.82, 1.36), but factor 2 (previous stroke, low HDL cholesterol and high triglycerides) (HR 1.34, CI 1. 06, 1.69, P=0.014) and factor 3 (age, systolic blood pressure, urinary albumin/creatinine ratio, left ventricular hypertrophy) (HR 1.44, CI 1.15, 1.82, P=0.002) predicted CHD events.

CONCLUSIONS

Our study supports the notion that the insulin resistance syndrome is a risk factor for CHD in elderly men.

Prandial glucose regulation and cardiovascular disease in type 2 diabetes

Type 2 diabetes is associated with an increased risk for cardiovascular disease. In recent years, prospective studies have indicated that, in addition to conventional risk factors, glycaemic control of diabetes predicts cardiovascular disease in both middle-aged and elderly patients with Type 2 diabetes. However, there are no consistent data from different studies to indicate that postprandial glucose is a better predictor for cardiovascular risk than fasting glucose level. Although no clinical trials are available to show that improving glycaemic control prevents cardiovascular mortality and morbidity, recent studies imply that hyperglycaemia in patients with Type 2 diabetes should be treated more intensively than recommended by current guidelines

Exopolysaccharide-producing bacteria from sugar beets

Six hundred microorganisms were isolated from sugar beets collected from different parts of Finland to study their slime production. A total of 170 of them produced exopolysaccharides, of which 35% were heteropolysaccharides. The yield of heteropolysaccharides from sucrose was lower than that of dextrans. Five isolates, which were chosen for closer study, were identified as Leuconostoc mesenteroides (two species), Rahnella aquatilis (two species), and Enterobacter amnigenus.

The cardiac beta-myosin heavy chain gene is not the predominant gene for hypertrophic cardiomyopathy in the Finnish population

OBJECTIVES

The aim of the study was to screen 36 unrelated patients with hypertrophic cardiomyopathy (HCM; 16 familial and 20 sporadic cases) from a genetically homogeneous area in eastern Finland for variants in the cardiac beta-myosin heavy chain (beta-MHC) and alpha-tropomyosin (alpha-TM) genes.

BACKGROUND

Mutations in the beta-MHC and alpha-TM genes have been reported to be responsible for 30% to 40% and less than 5% of familial HCM cases, respectively. However, most genetic studies have included patients from tertiary care centers and are subject to referral bias.

METHODS

Exons 3-26 and 40 of the beta-MHC gene and the nine exons of the alpha-TM gene were screened with the PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) method. Linkage analyses between familial HCM locus and two intragenic polymorphic markers (MYO I and MYO II) of the beta-MHC gene were performed in 16 familial HCM kindreds.

RESULTS

A previously reported Arg719Trp (arginine converted to tryptophan in codon 719) mutation of the beta-MHC gene was found in one proband and two relatives. In addition, a novel Asn696Ser (asparagine converted to serine in codon 696) substitution was found in one HCM patient. No linkage between familial HCM and the beta-MHC gene was observed in 16 familial kindreds. A previously reported Aspl75Asn (aspartic acid converted to asparagine in codon 175) mutation of the alpha-TM gene was found in four probands and 16 relatives. Mutations in the beta-MHC and alpha-TM genes accounted for 6% and 25% familial HCM cases and 3% and 11% of all cases, respectively.

CONCLUSIONS

Our results indicate that the beta-MHC gene is not the predominant gene for HCM in the Finnish population, whereas HCM caused by the Aspl75Asn mutation of the a-TM gene is more common than previously reported.

A Pro12Ala substitution in PPARgamma2 associated with decreased receptor activity, lower body mass index and improved insulin sensitivity

The peroxisome proliferator-activated receptor-gamma (PPARgamma) is a transcription factor that has a pivotal role in adipocyte differentiation and expression of adipocyte-specific genes. The PPARgamma1 and gamma2 isoforms result from alternative splicing and have ligand-dependent and -independent activation domains. PPARgamma2 has an additional 28 amino acids at its amino terminus that renders its ligand-independent activation domain 5-10-fold more effective than that of PPARgamma1. Insulin stimulates the ligand-independent activation of PPARgamma1 and gamma2 (ref. 5), however, obesity and nutritional factors only influence the expression of PPARgamma2 in human adipocytes. Here, we report that a relatively common Pro12Ala substitution in PPARgamma2 is associated with lower body mass index (BMI; P=0.027; 0.015) and improved insulin sensitivity among middle-aged and elderly Finns. A significant odds ratio (4.35, P=0.028) for the association of the Pro/Pro genotype with type 2 diabetes was observed among Japanese Americans. The PPARgamma2 Ala allele showed decreased binding affinity to the cognate promoter element and reduced ability to transactivate responsive promoters. These findings suggest that the PPARgamma2 Pro12Ala variant may contribute to the observed variability in BMI and insulin sensitivity in the general population.

Glucokinase gene islet promoter region variant (G-->A) at nucleotide -30 is not associated with reduced insulin secretion in Finns

OBJECTIVE

To investigate the effect of the islet promoter region variant (G-->A) at nucleotide -30 of the glucokinase (GCK) gene on insulin levels in subjects with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and NIDDM.

RESEARCH DESIGN AND METHODS

The study population included 294 subjects with NGT, 83 subjects with IGT, and 36 subjects with NIDDM. Oral glucose tolerance tests (OGTTs) were performed in all subjects, and intravenous glucose tolerance tests (IVGTTs) were performed in subjects with NGT. The islet promoter region of the GCK gene was amplified with polymerase chain reaction and screened for the variant (-30) using single-strand conformation polymorphism analysis.

RESULTS

The islet promoter variant (-30) of the GCK gene was found in 17% of subjects with NGT, 23% of subjects with IGT, and 14% of patients with NIDDM (NS between the groups). Fasting, 1-h, and 2-h insulin levels, measured by OGTT, did not differ between subjects with and without this variant in any of the three groups. Furthermore, first-phase insulin secretion, determined by an IVGTT in subjects with NGT, did not associate with presence of the islet promoter region variant (-30) of the GCK gene.

CONCLUSIONS

These results indicate that the variant (-30) of the islet promoter region of the GCK gene does not have a significant effect on insulin secretion in Finnish subjects with NGT, IGT, or NIDDM.