Andries J. Smit

Skin Autofluorescence, a Measure of Cumulative Metabolic Stress and Advanced Glycation End Products, Predicts Mortality in Hemodialysis Patients

Tissue advanced glycation end products (AGE) are a measure of cumulative metabolic stress and trigger cytokines driven inflammatory reactions. AGE are thought to contribute to the chronic complications of diabetes and ESRD. Tissue autofluorescence is related to the accumulation of AGE. Therefore, skin autofluorescence (AF) may provide prognostic information on mortality in hemodialysis (HD) patients. Skin AF was measured noninvasively with an AF reader at baseline in 109 HD patients. Overall and cardiovascular mortality was monitored prospectively during a period of 3 yr. The AF reader was validated against AGE contents in skin biopsies from 29 dialysis patients. Forty-two of the 109 (38.5%) HD patients died. Cox regression analysis showed that AF was an independent predictor of overall and cardiovascular mortality (for overall mortality odds ratio [OR] 3.9), as were pre-existing cardiovascular disease (CVD; OR 3.1), C-reactive protein (OR 1.1), and serum albumin (OR 0.3). Multivariate analysis revealed that 65% of the variance in AF could be attributed to the independent effects of age, dialysis and renal failure duration, presence of diabetes, triglycerides levels, and C-reactive protein. AF was also independently linked to the presence of CVD at baseline (OR 8.8; P < 0.001). AF correlated with collagen-linked fluorescence (r = 0.71, P < 0.001), pentosidine (r = 0.75, P < 0.001), and carboxy(m)ethyllysine (both r = 0.45, P < 0.01). Skin AF is a strong and independent predictor of mortality in ESRD. This supports a role for AGE as a contributor to mortality and CVD and warrants interventions specifically aimed at AGE accumulation.

Association between increased arterial-wall thickness and impairment in ABCA1-driven cholesterol efflux: an observational study

BACKGROUND Decreased concentrations of HDL cholesterol are associated with increased cardiovascular risk. These concentrations are directly related to cholesterol efflux from cells-the first step and a key process in reverse cholesterol transport. Cholesterol efflux is mediated by the ATP-binding cassette A1 transporter (ABCA1), the rate-limiting step in the production of HDL. We aimed to assess the relation between cholesterol efflux, HDL concentrations, and arterial-wall changes in individuals with impaired ABCA1 function. METHODS We investigated 30 individuals from families with ABCA1 mutations, and 110 controls matched for age, sex, and ethnic origin. We measured concentrations of HDL cholesterol in plasma and intima-media thickness of the carotid arteries by B-mode ultrasonography in all participants. We also measured cholesterol efflux from skin fibroblasts in nine individuals with ABCA1 mutations and in ten controls. FINDINGS Individuals with ABCA1 mutations had lower amounts of cholesterol efflux, lower HDL cholesterol concentrations, and greater intima-media thicknesses than controls. An intima-media thickness at the upper limit of normal (0.80 mm) was reached by age 55 years in the ABCA1 heterozygotes, and at age 80 years in unaffected controls (p<0.0001). Additionally, strong positive correlations were seen between HDL cholesterol concentrations and cholesterol efflux (r=0.90, p=0.001), and negative correlations between apolipoprotein-AI-mediated (r=-0.61, p=0.030) and HDL-particle-mediated (r=-0.60, p=0.018) efflux and intima-media thickness in the ABCA1 mutation carriers. INTERPRETATION These results show a direct relation between ABCA1-mediated cellular cholesterol efflux and arterial-wall thickness, and therefore suggest that increasing efflux could inhibit atherosclerosis progression before the manifestation of symptomatic cardiovascular disease.

ROC analysis of noninvasive tests for peripheral arterial disease

The purpose of this study is to evaluate the diagnostic accuracy of selected noninvasive tests for assessing peripheral arterial disease. The ankle/brachial index (ABI) and the femoral and popliteal pulsatility indices (PI), and combinations of these tests, were evaluated using receiver operating characteristic (ROC) analysis to determine their diagnostic accuracy depending on the localization of the disease. Verification bias, introduced by the preferential selection of patients for angiography based on the noninvasive test results, was examined. This study suggests that, in assessing whether a patient has significant peripheral arterial disease (lesions > or = 50%), determining an ABI is justified (ROC area 0.95 +/- 0.02). For disease localized to the aortoiliac segment, performing a single test, the femoral PI, is sufficient (ROC area 0.80 +/- 0.04). For disease including the femoropopliteal and infrapopliteal segments, a combination of tests is necessary. Utilized threshold values need to be adjusted for verification bias.

Advanced glycation end-products (AGEs) and heart failure: pathophysiology and clinical implications.

Advanced glycation end‐products (AGEs) are molecules formed during a non‐enzymatic reaction between proteins and sugar residues, called the Maillard reaction. AGEs accumulate in the human body with age, and accumulation is accelerated in the presence of diabetes mellitus. In patients with diabetes, AGE accumulation is associated with the development of cardiac dysfunction. Enhanced AGE accumulation is not restricted to patients with diabetes, but can also occur in renal failure, enhanced states of oxidative stress, and by an increased intake of AGEs. Several lines of evidence suggest that AGEs are related to the development and progression of heart failure in non‐diabetic patients as well. Preliminary small intervention studies with AGE cross‐link breakers in heart failure patients have shown promising results. In this review, the role of AGEs in the development of heart failure and the role of AGE intervention as a possible treatment for heart failure are discussed.

Skin Autofluorescence: A Tool to Identify Type 2 Diabetic Patients at Risk for Developing Microvascular Complications

OBJECTIVE—Skin autofluorescence is a noninvasive measure of the level of tissue accumulation of advanced glycation end products, representing cumulative glycemic and oxidative stress. Recent studies have already shown a relationship between skin autofluorescence and diabetes complications, as well as the predictive value of skin autofluorescence for total and cardiovascular mortality in type 2 diabetes. Our aim was to investigate the predictive value of skin autofluorescence for the development of microvascular complications in type 2 diabetes. RESEARCH DESIGN AND METHODS—At baseline, skin autofluorescence of 973 type 2 diabetic patients with well-controlled diabetes was noninvasively measured with an autofluorescence reader. The aggregate clinical outcome was defined as the development of any diabetes-associated microvascular complication of 881 surviving patients, which was assessed at baseline and at the end of follow-up. Single end points were the development of diabetes-associated retinopathy, neuropathy, and (micro)albuminuria. RESULTS—After a mean follow-up period of 3.1 years, baseline skin autofluorescence was significantly higher in patients who developed any microvascular complication, neuropathy, or (micro)albuminuria but not in those who developed retinopathy. Multivariate analyses showed skin autofluorescence as a predictor for development of any microvascular complication along with A1C, for development of neuropathy along with smoking, and for development of (micro)albuminuria together with sex, A1C, and diabetes duration. Skin autofluorescence did not have predictive value for the development of retinopathy, albeit diabetes duration did. CONCLUSIONS—Our study is the first observation of skin autofluorescence measurement as an independent predictor of development of microvascular complications in type 2 diabetes.

Symptom scoring systems to diagnose distal polyneuropathy in diabetes : the Diabetic Neuropathy Symptom score

Aims To provide one of the diagnostic categories for distal diabetic polyneuro‐pathy,several symptom scoring systems are available, which are often extensive andlack in validation. We validated a new four‐item Diabetic Neuropathy Symptom (DNS) scorefor diagnosing distal diabetic polyneuropathy.

Acute Chemotherapy-Induced Cardiovascular Changes in Patients With Testicular Cancer

PURPOSE After cisplatin- and bleomycin-containing chemotherapy for testicular cancer, part of the patient population will develop acute or long-term cardiovascular toxicity. It is largely unknown whether standard tests can be used to assess chemotherapy-induced cardiovascular changes. PATIENTS AND METHODS In 65 testicular cancer patients (median age, 27 years; range, 18 to 48 years), we measured the following cardiovascular parameters before and within 10 weeks after completion of cisplatin-based chemotherapy: platelet numbers, plasma levels of hemostatic and fibrinolytic factors, 24-hour ambulatory blood pressure, baroreflex sensitivity, intima-media thickness of the common carotid artery, and flow-mediated vasodilation of the brachial artery. RESULTS Compared with prechemotherapy values, the intima-media thickness of the carotid artery and plasma von Willebrand factor levels increased significantly after treatment. Platelet numbers and plasma levels of other hemostatic and fibrinolytic factors did not appear to change significantly. Blood pressure decreased significantly, but flow-mediated vasodilation and baroreflex sensitivity did not change. CONCLUSION In testicular cancer patients treated with cisplatin-based chemotherapy, we found an increase in plasma von Willebrand factor levels and in the intima-media thickness of the carotid artery. These changes may indicate chemotherapy-induced vascular damage and be of prognostic significance for the development of cardiovascular complications in the long term.

Simple Noninvasive Measurement of Skin Autofluorescence

Abstract: Accumulation of advanced glycation end products (AGEs) is thought to play a role in the pathogenesis of chronic complications of diabetes mellitus and renal failure. Several studies indicate that AGE accumulation in tissue may reflect the cumulative effect of hyperglycemia and oxidative stress over many years. Simple quantitation of AGE accumulation in tissue could provide a tool for assessing the risk of long‐term complications. Because several AGEs exhibit autofluorescence, we developed a noninvasive autofluorescence reader (AFR). Skin autofluorescence measured with the AFR correlates with collagen‐linked fluorescence and specific skin AGE levels from skin biopsy samples. Furthermore, skin autofluorescence correlates with long‐term glycemic control and renal function, and preliminary results show correlations with the presence of long‐term complications in diabetes. The AFR may be useful as a clinical tool for rapid assessment of risk for AGE‐related long‐term complications in diabetes and in other conditions associated with AGE accumulation.

Self-measurement of blood pressure at home reduces the need for antihypertensive drugs: a randomized, controlled trial.

It is still uncertain whether one can safely base treatment decisions on self-measurement of blood pressure. In the present study, we investigated whether antihypertensive treatment based on self-measurement of blood pressure leads to the use of less medication without the loss of blood pressure control. We randomly assigned 430 hypertensive patients to receive treatment either on the basis of self-measured pressures (n=216) or office pressures (OPs; n=214). During 1-year follow-up, blood pressure was measured by office measurement (10 visits), ambulatory monitoring (start and end), and self-measurement (8 times, self-pressure group only). In addition, drug use, associated costs, and degree of target organ damage (echocardiography and microalbuminuria) were assessed. The self-pressure group used less medication than the OP group (1.47 versus 2.48 drug steps; P<0.001) with lower costs (

Increased alpha-linolenic acid intake lowers C-reactive protein, but has no effect on markers of atherosclerosis

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