The relationship between flow-mediated dilatation and left ventricular function in type 2 diabetic patients with microalbuminuria

The continuums of impairment in vascular reactivity across the spectrum of cardiometabolic health: A systematic review and network meta-analysis

This study aimed to assess, for the first time, the change in vascular reactivity across the full spectrum of cardiometabolic health. Systematic searches were conducted in MEDLINE and EMBASE databases from their inception to March 13, 2017, including studies that assessed basal vascular reactivity in two or more of the following health groups (aged ≥18 years old): healthy, overweight, obesity, impaired glucose tolerance, metabolic syndrome, or type 2 diabetes with or without complications. Direct and indirect comparisons of vascular reactivity were combined using a network meta-analysis. Comparing data from 193 articles (7226 healthy subjects and 19344 patients), the network meta-analyses revealed a progressive impairment in vascular reactivity (flow-mediated dilation data) from the clinical onset of an overweight status (-0.41%, 95% CI, -0.98 to 0.15) through to the development of vascular complications in those with type 2 diabetes (-4.26%, 95% CI, -4.97 to -3.54). Meta-regressions revealed that for every 1 mmol/l increase in fasting blood glucose concentration, flow-mediated dilation decreased by 0.52%. Acknowledging that the time course of disease may vary between patients, this study demonstrates multiple continuums of vascular dysfunction where the severity of impairment in vascular reactivity progressively increases throughout the pathogenesis of obesity and/or insulin resistance, providing information that is important to enhancing the timing and effectiveness of strategies that aim to improve cardiovascular outcomes.

Endothelial function is associated with myocardial diastolic function in women with systemic lupus erythematosus

Endothelial dysfunction is associated with traditional and systemic lupus erythematosus (SLE)-specific risk factors, and early data suggest reversibility of endothelial dysfunction with therapy. The clinical relevance of endothelial function assessment has been limited by the lack of studies, demonstrating its prognostic significance and impact on early myocardial function. Therefore, we aimed to determine the association between endothelial and myocardial diastolic function in SLE women. Women with SLE and no coronary artery disease were prospectively recruited and underwent radionuclide myocardial perfusion imaging (MPI) (Jetstream, Philips, the Netherlands) to exclude subclinical myocardial ischemia. Cardiac and vascular functions were assessed in all patients (Alpha 10, Aloka, Tokyo). Diastolic function was assessed using pulse wave early (E) and late mitral blood inflow and myocardial tissue Doppler (mean of medial and lateral annulus e') velocities. Endothelial function was measured using brachial artery flow-mediated vasodilatation (FMD%). Univariate and multivariate linear regressions were used to assess the association between FMD% and myocardial diastolic function, adjusting for potential confounders. Thirty-eight patients without detectable myocardial ischemia on MPI were studied (mean age 44 ± 10 years; mean disease duration 14 ± 6 years). About 61 % of patients had normal diastolic function (E/e' ≤ 8), and 5 % of patients had definite diastolic dysfunction with E/e' > 13 (mean 7.1 ± 2.9). FMD% was associated with E/e' (regression coefficient β = -0.35; 95 % CI -0.62 to -0.08; p = 0.01) independent of systolic blood pressure, age, and SLICC/ACR Damage Index.

Impaired glucose tolerance, but not impaired fasting glucose, underlies left ventricular diastolic dysfunction

OBJECTIVE

Glucose intolerance is recognized as a predictor of congestive heart failure (CHF). However, the association of postprandial hyperglycemia or fasting hyperglycemia with CHF has not been clarified. We determined the impact of the total spectrum of glucose abnormalities on left ventricular (LV) geometry and diastolic function.

RESEARCH DESIGN AND METHODS

Two hundred and eighty-seven Japanese subjects who visited the university hospital to be checked for glucose intolerance or known type 2 diabetes were consecutively recruited. Participants underwent an oral glucose tolerance test if they had no history of diabetes, and LV geometry and LV systolic and diastolic function were analyzed by Doppler echocardiography.

RESULTS

The frequency of LV diastolic dysfunction in subjects with normal glucose tolerance, impaired fasting glucose (IFG), impaired glucose tolerance (IGT), newly detected diabetes, and known diabetes were 13, 22, 50, 51, and 61%, respectively (χ(2) = 54.2, P < 0.0001). IGT was a predictor for LV diastolic dysfunction after adjusting for age, sex, systolic blood pressure, and heart rate (odds ratio 3.43 [95% CI 1.09-11.2]), but IFG was not (0.49 [0.06-3.08]). IGT was a predictor after adjusting for established CHF risk factors but was no longer significant after adjusting for BMI and homeostasis model assessment of insulin resistance.

CONCLUSIONS

In this hospital-based registry of subjects without CHF, the prevalence of LV diastolic dysfunction was higher in subjects with IGT but not in those with IFG. Results suggest that IGT, as well as newly detected and known diabetes, could be linked to an increased risk of cardiovascular events, partly through LV diastolic dysfunction.

PPAR gamma agonist normalizes glomerular filtration rate, tissue levels of homocysteine, and attenuates endothelial-myocyte uncoupling in alloxan induced diabetic mice

Background: Homocysteine (Hcy) is an independent cardiovascular risk factor; however, in diabetes, the role of tissue Hcy leading to cardiac dysfunction is unclear.

Aims: To determine whether tissue Hcy caused endothelial-myocyte uncoupling and ventricular dysfunction in diabetes.

Methods: Diabetes was created in C57BL/6J male mice by injecting 65 mg/kg alloxan. To reverse diabetic complications, ciglitazone (CZ) was administered in the drinking water. Plasma glucose, Hcy, left ventricular (LV) tissue levels of Hcy and nitric oxide (NO) were measured. Glomerular filtration rate (GFR) was measured by inulin-FITC. Endothelial-myocyte coupling was measured in cardiac rings. In vivo diastolic relaxation and LV diameters were measured by a Millar catheter in LV and by M-mode echocardiography, respectively.

Results: Plasma glucose, GFR and LV tissue Hcy were increased in diabetic mice and were normalized after CZ treatment; whereas, elevated plasma Hcy level remained unchanged with or without CZ treatment. NO levels in the LV were found inversely related to tissue Hcy levels. Attenuated endothelial-myocyte function in diabetic mice was ameliorated by CZ treatment. Cardiac relaxation, the ratio of LV wall thickness to LV diameter was decreased in diabetes, and normalized after CZ treatment.

Conclusion: CZ normalized LV tissue levels of Hcy and ameliorated endothelial-myocyte coupling; therefore, specifically suggest the association of LV tissue Hcy levels with impair endothelial-myocyte function in diabetes.

Importance of low-grade albuminuria

The well-described association between chronic kidney disease and cardiovascular disease is typically thought to originate from loss of renal function, as estimated by the glomerular filtration rate. However, recent data suggest that urinary albumin excretion has an important role in this association. Albuminuria is a marker of underlying vascular dysfunction and has been correlated with structural and functional integrity of the vasculature. Although the traditional upper limit of normal daily albumin excretion has been 30 mg/d, recent epidemiologic data suggest that levels in the general population are actually much lower. Further, within this range of low-grade albuminuria (LGA), increasing excretion rates are associated with increasing risk of cardiovascular disease. This association is independent of renal function, and in the earliest stages of chronic kidney disease, LGA seems to be a more important determinant than the glomerular filtration rate. This emerging association underscores the complexity of albumin excretion, in which subtle changes in albumin excretion reflect widespread vascular processes. Using the key words albuminuria, low-grade albuminuria, and microalbuminuria in a PubMed search of literature from January 1, 1995, to February 29, 2008, this review summarizes the most recent data on LGA and its association with cardiovascular and renal disease.