Slightly elevated B-type natriuretic peptide levels in a non-heart failure range indicate a worse left ventricular diastolic function in individuals with, as compared with individuals without, type 2 diabetes: the Hoorn Study.

AIMS: Higher plasma B-type natriuretic peptide (BNP) in a non-heart failure (HF) range predicts HF and cardiovascular disease (CVD) mortality in the general population. Heart failure is highly prevalent in type 2 diabetes mellitus (T2DM), but associations of BNP to left ventricular (LV) mass and function in individuals with a different glucose status have not been compared. We therefore aimed to explore (i) the association of BNP levels in a non-HF range with structural and functional markers of LV function, and (ii) possible effect modification by glucose tolerance categories. METHODS AND RESULTS: Linear regression analyses were performed to investigate associations of BNP with 2D echocardiographic measures of LV mass index, LV systolic function, and markers of LV diastolic function in a population-based study of men and women with normal glucose metabolism (NGM, n = 197), impaired glucose metabolism (IGM, n = 128), or T2DM (n = 204). Patients were aged between 50 and 87 years, had BNP levels below 50 pmol/L, and no LV wall motion abnormalities. B-type natriuretic peptide levels ranged from 0.4 to 46.1 pmol/L, the median was 4.2 pmol/L. Higher BNP was significantly associated with increased LV mass and deteriorated LV diastolic function, but not with LV systolic function. B-type natriuretic peptide was more strongly associated with LV diastolic function in T2DM compared with NGM and IGM. CONCLUSION: B-type natriuretic peptide was associated with LV mass and markers of LV diastolic function, and the association of BNP with the latter appeared to be particularly strong in individuals with T2DM. This implies that the presence or absence of T2DM should be taken into account if BNP levels are used to assess CVD risk.

Acute effects of decaffeinated coffee and the major coffee components chlorogenic acid and trigonelline on glucose tolerance.

OBJECTIVE: Coffee consumption has been associated with lower risk of type 2 diabetes. We evaluated the acute effects of decaffeinated coffee and the major coffee components chlorogenic acid and trigonelline on glucose tolerance. RESEARCH DESIGN AND METHODS: We conducted a randomized crossover trial of the effects of 12 g decaffeinated coffee, 1 g chlorogenic acid, 500 mg trigonelline, and placebo (1 g mannitol) on glucose and insulin concentrations during a 2-h oral glucose tolerance test (OGTT) in 15 overweight men. RESULTS: Chlorogenic acid and trigonelline ingestion significantly reduced glucose (-0.7 mmol/l, P = 0.007, and -0.5 mmol/l, P = 0.024, respectively) and insulin (-73 pmol/l, P = 0.038, and -117 pmol/l, P = 0.007) concentrations 15 min following an OGTT compared with placebo. None of the treatments affected insulin or glucose area under the curve values during the OGTT compared with placebo. CONCLUSIONS: Chlorogenic acid and trigonelline reduced early glucose and insulin responses during an OGTT.

The heritability of HbA1c and fasting blood glucose in different measurement settings.

In an extended twin study we estimated the heritability of fasting HbA1c and blood glucose levels. Blood glucose was assessed in different settings (at home and in the clinic). We tested whether the genetic factors influencing fasting blood glucose levels overlapped with those influencing HbA1c and whether the same genetic factors were expressed across different settings. Fasting blood glucose was measured at home and during two visits to the clinic in 77 healthy families with same-sex twins and siblings, aged 20 to 45 years. HbA1c was measured during the first clinic visit. A 4-variate genetic structural equation model was used that estimated the heritability of each trait and the genetic correlations among traits. Heritability explained 75% of the variance in HbA1c. The heritability of fasting blood glucose was estimated at 66% at home and lower in the clinic (57% and 38%). Fasting blood glucose levels were significantly correlated across settings (0.34 < r < 0.54), mostly due to a common set of genes that explained between 53% and 95% of these correlations. Correlations between HbA1c and fasting blood glucoses were low (0.11 < r < 0.23) and genetic factors influencing HbA1c and fasting glucose were uncorrelated. These results suggest that in healthy adults the genes influencing HbA1c and fasting blood glucose reflect different aspects of the glucose metabolism. As a consequence these two glycemic parameters can not be used interchangeably in diagnostic procedures or in studies attempting to find genes for diabetes. Both contribute unique (genetic) information.

Albuminuria, but not estimated glomerular filtration rate, is associated with maladaptive arterial remodeling: the Hoorn Study.

OBJECTIVE: Arterial remodeling aims to maintain a constant circumferential wall stress (sigmac). A failing remodeling process is associated with stroke. Data on the relationship between chronic kidney disease and arterial remodeling are scarce. METHODS: We investigated the association between a lower glomerular filtration rate (GFR) and microalbuminuria with arterial remodeling of the common carotid artery (CCA) in a population-based study of 806 patients. CCA properties including intima-media thickness and interadventitial diameter (IAD) were assessed. Lumen diameter, circumferential wall tension (CWT), and circumferential wall stress (sigmac) were calculated. GFR was estimated (eGFR) by the Modification of Diet in Renal Disease formula. Albuminuria was expressed as urinary albumin/creatinine ratio. RESULTS: Mean eGFR was 60.3 (+/-10.8) ml/min/1.73 m2; median urinary albumin/creatinine ratio was 0.57 (range 0.10-26.6 mg/mmol). After adjustment for age, sex, glucose tolerance status, and prevalent cardiovascular disease, eGFR was not independently associated with CCA properties. A greater urinary albumin/creatinine ratio (per quartile) was associated with a greater lumen diameter [regression coefficient beta with 95% confidence interval, 0.14 (0.08-0.20; P < 0.01)], IAD [0.15 (0.09-0.21; P < 0.01)], CWT [0.95 (0.52-1.38; P < 0.01)], and sigmac [1.7 (0.5-2.9; P < 0.01)] but not with a greater IMT [0.01 (-0.002-0.02; P = 0.12)]. Additional adjustments for mean arterial pressure, pulse pressure, and eGFR did not change the results. CONCLUSION: Greater albuminuria is independently associated with an increase in lumen diameter and IAD of the CCA. In addition, greater albuminuria is associated with a maladaptive carotid remodeling process as shown by an increase in CWT and sigmac. These findings may explain, why microalbuminuria is associated with a greater risk of cardiovascular disease and especially stroke.

Homocysteine, S-adenosylmethionine and S-adenosylhomocysteine are associated with retinal microvascular abnormalities: the Hoorn Study.

The aim of the present study was to investigate the relationship between homocysteine and homocysteine metabolism components and retinal microvascular disorders in subjects with and without Type 2 diabetes. In this population-based study of 256 participants, aged 60-85 years, we determined total plasma homocysteine, SAM (S-adenosylmethionine) and SAH (S-adenosylhomocysteine) in plasma and erythrocytes, total folate in serum and erythrocytes, 5-MTHF (5-methyltetrahydrofolate), and vitamins B12 and B6. Participants were examined ophthalmologically by means of indirect funduscopy and two-field 45 degrees fundus photography, and were graded for retinopathy and retinal sclerotic vessel abnormalities. A computer-assisted method was used to measure retinal vessel diameters. Total plasma homocysteine was inversely associated with retinal arteriolar diameters {standardized beta, -0.20 [95% CI (confidence interval), -0.33 to -0.07]} or a decrease of 3.78 microm CRAEs (central retinal arteriolar equivalents) per 1 S.D. increase in homocysteine level (=4.6 micromol/l). In addition, the SAM/SAH ratio in plasma was inversely associated with retinal sclerotic vessel abnormalities and retinopathy [odds ratios, 0.61 (95% CI, 0.39-0.96) and 0.50 (95% CI, 0.30-0.83) per 1 S.D. respectively]. The associations were independent of age, sex, glucose tolerance status, other homocysteine metabolism components and cardiovascular risk factors. In conclusion, the results of the present study support the concept that total plasma homocysteine and a low SAM/SAH ratio in plasma, which may reflect reduced transmethylation reactions, may contribute to the pathogenesis of (retinal) microangiopathy.

Endothelial dysfunction and low-grade inflammation explain much of the excess cardiovascular mortality in individuals with type 2 diabetes: the Hoorn Study.

OBJECTIVE: The mechanisms responsible for the increased cardiovascular disease risk that accompanies type 2 diabetes (T2D) remain poorly understood. It is commonly held that endothelial dysfunction and low-grade inflammation can explain, at least in part, why deteriorating glucose tolerance is associated with cardiovascular disease. However, there is no direct evidence for this contention. METHODS AND RESULTS: In this population-based study (n=631), T2D was cross-sectionally associated with both endothelial dysfunction and low-grade inflammation, whereas impaired glucose metabolism (IGM) was associated only with low-grade inflammation. These findings were independent of other risk factors that accompany T2D or IGM. During a follow-up of 11.7 years (median; range 0.5 to 13.2 years), low-grade inflammation was associated with a greater risk of cardiovascular mortality (hazard ratio, 1.43 [95% CI, 1.17 to 1.77] per 1 SD difference). For endothelial dysfunction, the association with cardiovascular mortality was stronger in diabetic (hazard ratio, 1.87 [95% CI, 1.43 to 2.45]) than in nondiabetic individuals (hazard ratio, 1.23 [95% CI, 0.86 to 1.75]; P interaction=0.06). Finally, T2D-associated endothelial dysfunction and low-grade inflammation explained approximately 43% of the increase in cardiovascular mortality risk conferred by T2D. CONCLUSIONS: These data emphasize the necessity of randomized controlled trials of strategies that aim to decrease cardiovascular disease risk by improving endothelial function and decreasing low-grade inflammation, especially for T2D patients.

Mitochondrial diabetes: molecular mechanisms and clinical presentation.

Mutations in mitochondrial DNA (mtDNA) associate with various disease states. A few mtDNA mutations strongly associate with diabetes, with the most common mutation being the A3243G mutation in the mitochondrial DNA-encoded tRNA(Leu,UUR) gene. This article describes clinical characteristics of mitochondrial diabetes and its molecular diagnosis. Furthermore, it outlines recent developments in the pathophysiological and molecular mechanisms leading to a diabetic state. A gradual development of pancreatic beta-cell dysfunction upon aging, rather than insulin resistance, is the main mechanism in developing glucose intolerance. Carriers of the A3243G mutation show during a hyperglycemic clamp at 10 mmol/l glucose a marked reduction in first- and second-phase insulin secretion compared with noncarriers. The molecular mechanism by which the A3243G mutation affects insulin secretion may involve an attenuation of cytosolic ADP/ATP levels leading to a resetting of the glucose sensor in the pancreatic beta-cell, such as in maturity-onset diabetes of the young (MODY)-2 patients with mutations in glucokinase. Unlike in MODY2, which is a nonprogressive form of diabetes, mitochondrial diabetes does show a pronounced age-dependent deterioration of pancreatic function indicating involvement of additional processes. Furthermore, one would expect that all mtDNA mutations that affect ATP synthesis lead to diabetes. This is in contrast to clinical observations. The origin of the age-dependent deterioration of pancreatic function in carriers of the A3243G mutation and the contribution of ATP and other mitochondrion-derived factors such as reactive oxygen species to the development of diabetes is discussed.