Skin autofluorescence predicts new cardiovascular disease and mortality in people with type 2 diabetes.

BACKGROUND: Skin autofluorescence (SAF) is a non-invasive marker of tissue accumulation of advanced glycation endproducts (AGE). Recently, we demonstrated in the general population that elevated SAF levels predict the development of type 2 diabetes (T2D), cardiovascular disease (CVD) and mortality. We evaluated whether elevated SAF may predict the development of CVD and mortality in individuals with T2D. METHODS: We included 2349 people with T2D, available baseline SAF measurements (measured with the AGE reader) and follow-up data from the Lifelines Cohort Study. Of them, 2071 had no clinical CVD at baseline. 60% were already diagnosed with diabetes (median duration 5, IQR 2-9 years), while 40% were detected during the baseline examination by elevated fasting blood glucose ≥7.0 mmol/l) and/or HbA1c ≥6.5% (48 mmol/mol). RESULTS: Mean (±SD) age was 57 ± 12 yrs., BMI 30.2 ± 5.4 kg/m2. 11% of participants with known T2D were treated with diet, the others used oral glucose-lowering medication, with or without insulin; 6% was using insulin alone. Participants with known T2D had higher SAF than those with newly-detected T2D (SAF Z-score 0.56 ± 0.99 vs 0.34 ± 0.89 AU, p < 0.001), which reflects a longer duration of hyperglycaemia in the former group. Participants with existing CVD and T2D had the highest SAF Z-score: 0.78 ± 1.25 AU. During a median follow-up of 3.7 yrs., 195 (7.6%) developed an atherosclerotic CVD event, while 137 (5.4%) died. SAF was strongly associated with the combined outcome of a new CVD event or mortality (OR 2.59, 95% CI 2.10-3.20, p < 0.001), as well as incidence of CVD (OR 2.05, 95% CI 1.61-2.61, p < 0.001) and death (OR 2.98, 2.25-3.94, p < 0.001) as a single outcome. In multivariable analysis for the combined endpoint, SAF retained its significance when sex, systolic blood pressure, HbA1c, total cholesterol, eGFR, as well as antihypertensive and statin medication were included. In a similar multivariable model, SAF was independently associated with mortality as a single outcome, but not with incident CVD. CONCLUSIONS: Measuring SAF can assist in prediction of incident cardiovascular disease and mortality in individuals with T2D. SAF showed a stronger association with future CVD events and mortality than cholesterol or blood pressure levels.

Skin autofluorescence predicts incident type 2 diabetes, cardiovascular disease and mortality in the general population.

AIMS/HYPOTHESIS: Earlier studies have shown that skin autofluorescence measured with an AGE reader estimates the accumulation of AGEs in the skin, which increases with ageing and is associated with the metabolic syndrome and type 2 diabetes. In the present study, we examined whether the measurement of skin autofluorescence can predict 4 year risk of incident type 2 diabetes, cardiovascular disease (CVD) and mortality in the general population. METHODS: For this prospective analysis, we included 72,880 participants of the Dutch Lifelines Cohort Study, who underwent baseline investigations between 2007 and 2013, had validated baseline skin autofluorescence values available and were not known to have diabetes or CVD. Individuals were diagnosed with incident type 2 diabetes by self-report or by a fasting blood glucose ≥7.0 mmol/l or HbA1c ≥48 mmol/mol (≥6.5%) at follow-up. Participants were diagnosed as having incident CVD (myocardial infarction, coronary interventions, cerebrovascular accident, transient ischaemic attack, intermittent claudication or vascular surgery) by self-report. Mortality was ascertained using the Municipal Personal Records Database. RESULTS: After a median follow-up of 4 years (range 0.5-10 years), 1056 participants (1.4%) had developed type 2 diabetes, 1258 individuals (1.7%) were diagnosed with CVD, while 928 (1.3%) had died. Baseline skin autofluorescence was elevated in participants with incident type 2 diabetes and/or CVD and in those who had died (all p < 0.001), compared with individuals who survived and remained free of the two diseases. Skin autofluorescence predicted the development of type 2 diabetes, CVD and mortality, independent of several traditional risk factors, such as the metabolic syndrome, glucose and HbA1c. CONCLUSIONS/INTERPRETATION: The non-invasive skin autofluorescence measurement is of clinical value for screening for future risk of type 2 diabetes, CVD and mortality, independent of glycaemic measures and the metabolic syndrome.

Skin Autofluorescence, a Measure of Cumulative Metabolic Stress and Advanced Glycation End Products, Decreases During the Summer in Dialysis Patients.

Tissue advanced glycation end products (AGEs) are a measure of cumulative metabolic and oxidative stress and cytokine-driven inflammatory reactions. AGEs are thought to contribute to the cardiovascular complications of hemodialysis (HD) patients. Skin autofluorescence (SAF) is related to the tissue accumulation of AGEs and rises with age. SAF is one of the strongest prognostic markers of mortality in these patients. The content of AGEs is high in barbecue food. Due to the location in northern Sweden, there is a short intense barbecue season between June and August. The aim of this study was to investigate if seasonal variations in SAF exist in HD patients, especially during the barbecue season. SAF was measured noninvasively with an AGE Reader in 34 HD-patients (15 of those with diabetes mellitus, DM). Each time the median of three measures were used. Skin-AF was measured before and after each one HD at the end of February and May in 31 patients (22 men/9 women); the end of May and August in 28 (20 m/8 w); the end of August and March in 25 (19 m/6 w). Paired statistical analyses were performed during all four periods (n = 23, 17 m/6 w); as was HbA1c of those with DM. There was at a median 5.6% increase in skin-AF during the winter period (February-May, P = 0.004) and a 10.6% decrease in the skin-AF during the summer (May-August, P < 0.001). HbA1c in the DM rose during the summer (P = 0.013). In conclusion, skin-AF decreased significantly during the summer. Future studies should look for favorable factors that prevent skin-AF and subsequently cardiovascular diseases.

Skin- and Plasmaautofluorescence in hemodialysis with glucose-free or glucose-containing dialysate.

BACKGROUND: Haemodialysis (HD) patients suffer from an increased risk of cardiovascular disease (CVD). Skin autofluorescence (SAF) is a strong marker for CVD. SAF indirectly measures tissue advanced glycation end products (AGE) being cumulative metabolites of oxidative stress and cytokine-driven inflammatory reactions. The dialysates often contain glucose. METHODS: Autofluorescence of skin and plasma (PAF) were measured in patients on HD during standard treatment (ST) with a glucose-containing dialysate (n = 24). After that the patients were switched to a glucose-free dialysate (GFD) for a 2-week period. New measurements were performed on PAF and SAF after 1 week (M1) and 2 weeks (M2) using GFD. Nonparametric paired statistical analyses were performed between each two periods. RESULTS: SAF after HD increased non-significantly by 1.2% while when a GFD was used during HD at M1, a decrease of SAF by 5.2% (p = 0.002) was found. One week later (M2) the reduction of 1.6% after the HD was not significant (p = 0.33). PAF was significantly reduced during all HD sessions. Free and protein-bound PAF decreased similarly whether glucose containing or GFD was used. The HD resulted in a reduction of the total PAF of approximately 15%, the free compound of 20% and the protein bound of 10%. The protein bound part of PAF corresponded to approximately 56% of the total reduction. The protein bound concentrations after each HD showed the lowest value after 2 weeks using glucose-free dialysate (p < 0.05). The change in SAF could not be related to a change in PAF. CONCLUSIONS: When changing to a GFD, SAF was reduced by HD indicating that such measure may hamper the accumulation and progression of deposits of AGEs to protein in tissue, and thereby also the development of CVD. Glucose-free dialysate needs further attention. Protein binding seems firm but not irreversible. TRIAL REGISTRATION: ISRCTN registry: ISRCTN13837553 . Registered 16/11/2016 (retrospectively registered).

Lifestyle and clinical determinants of skin autofluorescence in a population-based cohort study.

BACKGROUND: Skin autofluorescence (SAF) is a noninvasive marker of advanced glycation end products (AGEs). In diabetes, higher SAF levels have been positively associated with long-term complications, cardiovascular morbidity and mortality. Because little is known about the factors that influence SAF in nondiabetic individuals, we assessed the association of clinical and lifestyle parameters with SAF as well as their interactions in a large-scale, nondiabetic population and performed the same analysis in a type 2 diabetic subgroup. METHODS: In a cross-sectional study in participants from the LifeLines Cohort Study, extensive clinical and biochemical phenotyping, including SAF measurement, was assessed in 9009 subjects of whom 314 (3·5%) subjects with type 2 diabetes. RESULTS: Mean SAF was 2·04 ± 0·44 arbitrary units (AU) in nondiabetic individuals and 2·44 ± 0·55 AU in type 2 diabetic subjects (P < 0·0001). Multivariate backward regression analysis showed that in the nondiabetic population, SAF was significantly and independently associated with age, BMI, HbA1c, creatinine clearance, genetic polymorphism in NAT2 (rs4921914), current smoking, pack-years of smoking and coffee consumption. In the type 2 diabetic group, a similar set of factors was associated with SAF, except for coffee consumption. CONCLUSIONS: In addition to the established literature on type 2 diabetes, we have demonstrated that SAF levels are associated with several clinical and lifestyle factors in the nondiabetic population. These parameters should be taken into consideration when using SAF as a screening or prediction tool for populations at risk for cardiovascular disease and diabetes.

GWAS identifies an NAT2 acetylator status tag single nucleotide polymorphism to be a major locus for skin fluorescence.

AIMS/HYPOTHESIS: Skin fluorescence (SF) is a non-invasive marker of AGEs and is associated with the long-term complications of diabetes. SF increases with age and is also greater among individuals with diabetes. A familial correlation of SF suggests that genetics may play a role. We therefore performed parallel genome-wide association studies of SF in two cohorts. METHODS: Cohort 1 included 1,082 participants, 35-67 years of age with type 1 diabetes. Cohort 2 included 8,721 participants without diabetes, aged 18-90 years. RESULTS: rs1495741 was significantly associated with SF in Cohort 1 (p < 6 × 10(-10)), which is known to tag the NAT2 acetylator phenotype. The fast acetylator genotype was associated with lower SF, explaining up to 15% of the variance. In Cohort 2, the top signal associated with SF (p = 8.3 × 10(-42)) was rs4921914, also in NAT2, 440 bases upstream of rs1495741 (linkage disequilibrium r (2) = 1.0 for rs4921914 with rs1495741). We replicated these results in two additional cohorts, one with and one without type 1 diabetes. Finally, to understand which compounds are contributing to the NAT2-SF signal, we examined 11 compounds assayed from skin biopsies (n = 198): the fast acetylator genotype was associated with lower levels of the AGEs hydroimidazolones of glyoxal (p = 0.017). CONCLUSIONS/INTERPRETATION: We identified a robust association between NAT2 and SF in people with and without diabetes. Our findings provide proof of principle that genetic variation contributes to interindividual SF and that NAT2 acetylation status plays a major role.

Advanced glycation end-products and skin autofluorescence in end-stage renal disease: a review.

Chronic kidney disease (CKD), especially in its end stage, is marked by extremely high cardiovascular rates of morbidity and mortality; hemodialysis patients have a five-fold shorter life expectancy than healthy subjects of the same age. In CKD the metabolic products that accumulate in the body are so-called uremic toxins. These include advanced glycation end-products (AGE). AGE levels are markedly increased in CKD patients not only because of impaired excretion but also because of increased production. AGE formation has initially been described as a non-enzymatic reaction between proteins and glucose in the so-called Maillard reaction, but they are also more rapidly formed during oxidative stress and subsequent formation of reactive carbonyl compounds like (methyl)glyoxal. AGE accumulate in tissue where they cross-link with proteins, e.g., collagen, inducing tissue stiffening of blood vessels and skin. They may also interact with receptor of AGE (RAGE) and other receptors, which lead to activation of intracellular transduction mechanisms resulting in cytokine release and further tissue damage in CKD. The accumulation of AGE in the skin can be measured non-invasively using autofluorescence. The skin autofluorescence is a strong marker of cardiovascular mortality in CKD. The focus of this review is on the role of tissue and plasma AGE, and of skin autofluorescence as a proxy of tissue AGE accumulation, in the increase in cardiovascular disease in end stage renal disease (ESRD). This review will also present the possibility of reducing the AGE accumulation in ESRD patients using the following five methods: 1) use of low AGE peritoneal dialysis solutions; 2) use of advanced hemodialysis techniques; 3) use of AGE reducing drugs; 4) optimizing the nutrition of hemodialysis patients; and 5) renal transplantation.

Skin and plasma autofluorescence during hemodialysis: a pilot study.

Skin autofluorescence (AF) is related to the accumulation of advanced glycation end products (AGEs) and is one of the strongest prognostic markers of mortality in hemodialysis (HD) patients. The aim of this pilot study was to investigate whether changes in skin AF appear after a single HD session and if they might be related to changes in plasma AF. Skin and plasma AF were measured before and after HD in 35 patients on maintenance HD therapy (nine women and 26 men, median age 68 years, range 33-83). Median dialysis time was 4 h (range 3-5.5). Skin AF was measured noninvasively with an AGE Reader, and plasma AF was measured before and after HD at 460 nm after excitation at 370 nm. The HD patients had on average a 65% higher skin AF value than age-matched healthy persons (P < 0.001). Plasma AF was reduced by 14% (P < 0.001), whereas skin AF was not changed after a single HD treatment. No significant influence of the reduced plasma AF on skin AF levels was found. This suggests that the measurement of skin AF can be performed during the whole dialysis period and is not directly influenced by the changes in plasma AF during HD.

Increase in skin autofluorescence and release of heart-type fatty acid binding protein in plasma predicts mortality of hemodialysis patients.

Advanced glycation end-products (AGEs) are uremic toxins that accumulate progressively in hemodialysis (HD) patients. The aim of this study was to assess the 1-year increase in skin autofluorescence (ΔAF), a measure of AGEs accumulation and plasma markers, as predictors of mortality in HD patients. One hundred sixty-nine HD patients were enrolled in this study. Skin autofluorescence was measured twice, 1 year apart using an AGE Reader (DiagnOptics Technologies BV, Groningen, The Netherlands). Besides routine blood chemistry, additional plasma markers including superoxide dismutase, myeloperoxydase, intercellular adhesion molecule 1 (ICAM-1), C-reactive protein (hs-CRP), heart-type fatty acid binding protein (H-FABP), and von Willebrand factor were measured at baseline. The mortality of HD patients was followed for 36 months. Skin autofluorescence values of the HD patients at the two time points were significantly higher (P < 0.001) than those of healthy subjects of the same age. Mean 1-year ΔAF of HD patients was 0.16 ± 0.06, which was around seven- to ninefold higher than 1-year ΔAF in healthy subjects. Multivariate Cox regression showed that age, hypertension, 1-year ΔAF, hs-CRP, ICAM-1, and H-FABP were independent predictors of overall mortality. Hypertension, 1-year ΔAF, hs-CRP, and H-FABP were also independent predictors of cardiovascular mortality. One-year ΔAF and plasma H-FABP, used separately and in combination, are strong predictors of overall and cardiovascular mortality in HD patients.

Skin color independent assessment of aging using skin autofluorescence.

Skin autofluorescence (AF) for the non-invasive assessment of the amount of accumulated tissue Advanced Glycation Endproducts (AGEs) increases with aging. In subjects with darker skin colors, measurements typically result in lower AF values than in subjects with fair skin colors, e.g. due to selective absorption by skin compounds. Our aim was to provide a new method for calculating skin AF, yielding values that are independent of skin color. The deviation of skin AF of healthy subjects with various darker skin types (N = 99) compared to reference values from Caucasians showed to be a function of various parameters that were derived from reflectance and emission spectra in the UV and visible range (adjusted R(2) = 80%). Validation of the new algorithm, based on these findings, in a separate dataset (N = 141) showed that results of skin AF can now be obtained to assess skin AGEs independently of skin color.

Carotid artery intima media thickness associates with skin autofluoresence in non-diabetic subjects without clinically manifest cardiovascular disease.

BACKGROUND: Skin autofluorescence (skin AF) is determined in part by accumulation of advanced glycation end products. Increased skin AF was shown previously to predict cardiovascular events independently of conventional risk factors. We determined the association of carotid artery intima media thickness (IMT), a marker of subclinical cardiovascular disease, with skin AF in subjects without diabetes or clinically manifest cardiovascular disease. METHODS: In a cross-sectional observational study, IMT, skin AF, lipids and apolipoproteins, C-reactive protein (CRP), insulin resistance and paraoxonase-1 activity were measured in 59 non-smoking, non-obese subjects without diabetes mellitus and cardiovascular disease (32 women; 12 subjects with metabolic syndrome (MetS)). RESULTS: In univariate analyses, skin AF was correlated with IMT (r = 0.265, P = 0.042), but not significantly with clinical factors, (apo)lipoproteins, CRP, insulin resistance and paraoxonase-1. In multiple linear regression analyses, IMT was determined independently by age (beta = 0.549, P < 0.001), apo B (beta = 0.236, P = 0.022) and skin AF (beta = 0.216, P = 0.035). IMT was also associated with skin AF (beta = 0.213, P = 0.046) in a model which included the presence of MetS. CONCLUSIONS: IMT is positively related to skin AF, independently of clinical factors, (apo)lipoproteins and MetS, suggesting that skin AF represents a determinant of subclinical atherosclerosis. Increased skin AF may reflect early abnormalities in processes involved in atherosclerosis development.

The effects of cryopreservation on red blood cell rheologic properties.

BACKGROUND: In transfusion medicine, frozen red blood cells (RBCs) are an alternative for liquid-stored RBCs. Little is known about the rheologic properties (i.e., aggregability and deformability) of thawed RBCs. In this study the rheologic properties of high-glycerol frozen RBCs and postthaw stored in saline-adenine-glucose-mannitol medium were compared to those of conventionally liquid-stored and fresh RBCs. STUDY DESIGN AND METHODS: Fresh RBCs were obtained from healthy volunteers. Leukoreduced liquid-stored and thawed deglycerolized RBC units were obtained from the Sanquin Blood Bank. RBCs were tested for aggregability (aggregation index [AI]), deformability (elongation index [EI]), and various hematologic variables. RESULTS: The AI of thawed RBCs was reduced, compared to fresh and liquid-stored RBCs (p<0.05). The EI of stored RBCs was significantly enhanced over a shear stress range of 2.0 to 50Pa compared to fresh RBCs (p<0.05). No significant differences in EI between thawed and 21- or 35-day liquid-stored RBCs were observed. The osmotic fragility, hemolysis, mean cell volume, and mean cell hemoglobin concentration of thawed RBCs were markedly altered, compared to fresh and liquid-stored RBCs (p< 0.05). The adenosine triphosphate (ATP) content of thawed RBCs was similar to 3- or 21-day liquid-stored and fresh RBCs. CONCLUSIONS: Thawed RBCs are more fragile than conventionally liquid-stored and fresh RBC. The freeze-thaw-wash process, however, did not adversely affect the aggregability and deformability or the ATP content of thawed RBCs. Based on the rheologic properties, cryopreserved RBCs are a valuable alternative to liquid-stored RBCs.

Is red blood cell rheology preserved during routine blood bank storage?

BACKGROUND: Red blood cell (RBC) units stored for more than 2 weeks at 4 degrees C are currently considered of impaired quality. This opinion has primarily been based on altered RBC rheologic properties (i.e., enhanced aggregability, reduced deformability, and elevated endothelial cell interaction), during prolonged storage of nonleukoreduced RBC units. In this study, the rheologic properties and cell variables of leukoreduced RBC units, during routine blood bank storage in saline-adenine-glucose-mannitol, were investigated. STUDY DESIGN AND METHODS: Ten leukoreduced RBC units were stored at the blood bank for 7 weeks at 4 degrees C. RBCs were tested weekly for aggregability, deformability, and other relevant variables. RESULTS: RBC aggregability was significantly reduced after the first week of storage but recovered during the following weeks. After 7 weeks aggregability was slightly, but significantly, reduced (46.9 + or - 2.4-44.3 + or - 2.2 aggregation index). During storage the osmotic fragility was not significantly enhanced (0.47 + or - 0.01% phosphate-buffered saline) and the deformability at shear stress of 3.9 Pa was not significantly reduced (0.36 + or - 0.01 elongation index [EI]). The deformability at 50 Pa was reduced (0.58 + or - 0.01-0.54 + or - 0.01 EI) but remained within reference values (0.53 + or - 0.04). During 5 weeks of storage, adenosine triphosphate was reduced by 54% whereas mean cell volume, pH, and mean cell hemoglobin concentration were minimally affected. CONCLUSIONS: RBC biochemical and physical alterations during storage minimally affected the RBC ability to aggregate and deform, even after prolonged storage. The rheologic properties of leukoreduced RBC units were well preserved during 7 weeks of routine blood bank storage.

Does hepatitis C increase the accumulation of advanced glycation end products in haemodialysis patients?

BACKGROUND: Hepatitis C may cause increased levels of oxidative stress that contribute to accumulation of advanced glycation end products (AGEs), which increase the risk of cardiovascular disease (CVD). The aim of this study was to determine the influence of hepatitis C on AGE accumulation in haemodialysis patients. METHODS: AGE accumulation was measured by means of skin autofluorescence (AF) in 92 haemodialysis (HD) patients and 93 age-matched healthy controls. In the HD patients, CVD-related biochemical variables were also measured. The HD patients were tested for hepatitis C virus (HCV) antibodies and allocated to a HCV+ or HCV- group. RESULTS: Skin AF of the healthy subjects was lower than skin AF in the HD patients (3.13 +/- 0.95 vs 2.2 +/- 0.47; P < 0.001). We calculated the average increase of skin AF in the healthy subjects to be 0.017 arbitrary units per year, being 14 times lower than in HD patients with CVD only and 20 times lower than in HD patients suffering from combined CVD and diabetes mellitus (DM). Multivariate regression analysis showed that AGE accumulation in HD patients can be described by the independent effects of age, DM, CVD and HD vintage. Although inter-cellular adhesion molecule 1 and liver enzymes were elevated in HCV+ HD patients, levels of oxidative stress markers and skin AF were not significantly different between HCV+ and HCV- HD patients. CONCLUSIONS: AGE accumulation was higher in the HD patients than in the healthy controls. AGE accumulation did not differ in HCV+ and HCV- HD patients. This might be due to the fact that hepatitis C did not cause oxidative stress in our HD population. Independent markers of AGE accumulation were age, HD vintage, DM and CVD, but not hepatitis C.

Skin autofluorescence is a strong predictor of cardiac mortality in diabetes.

OBJECTIVE: Advanced glycation end products (AGEs) are biomarkers of metabolic stress and are thought to contribute to the increase of coronary heart disease (CHD) in diabetes. Tissue autofluorescence is related to the accumulation of AGEs. The aim of the present study was to evaluate the relationship between skin autofluorescence and metabolic burden (hyperglycemia and hyperlipidemia) and its relationship with CHD and mortality. RESEARCH DESIGN AND METHODS: Skin autofluorescence was measured noninvasively with an autofluorescence reader in 48 type 1 and 69 type 2 diabetic patients and 43 control subjects. The presence of CHD was observed at baseline and mortality during a follow-up period of 5 years. RESULTS: Autofluorescence correlated with mean A1C, triglycerides, and LDL. Autofluorescence values further increased with age, microalbuminuria, dialysis treatment, and diabetes duration. Autofluorescence was strongly related to the presence of CHD (odds ratio 7.9) and predicted mortality (3.0). Multivariate analysis showed that autofluorescence was more strongly associated with CHD and mortality compared with A1C, triglycerides, and LDL. CONCLUSIONS: Skin autofluorescence is strongly related to cumulative metabolic burden. Skin autofluorescence seems strongly associated with cardiac mortality and may provide important clinical information for risk assessment.

Skin autofluorescence as a noninvasive marker of vascular damage in patients with type 2 diabetes.

OBJECTIVE: Advanced glycation end products (AGEs) are thought to have a role in the pathogenesis of diabetes complications. We recently reported the association between skin autofluorescence, as a measure of tissue AGE accumulation, and diabetic neuropathy in a selected diabetic population. In this study, we investigated the relation between skin autofluorescence and clinical variables including micro- and macrovascular complications in a type 2 diabetes primary care population. RESEARCH DESIGN AND METHODS: Clinical data and skin autofluorescence were obtained in the type 2 diabetes group (n = 973) and in a control group (n = 231). Skin autofluorescence was assessed by illumination of the lower arm with a fluorescent tube (peak intensity approximately 370 nm). RESULTS: Skin autofluorescence was significantly higher in type 2 diabetic patients compared with control subjects in each age category. Multiple regression analysis showed significant correlation of skin autofluorescence with age, sex, diabetes duration, BMI, smoking, HbA1c, plasma creatinine, HDL cholesterol, and albumin-to-creatinine ratio in the type 2 diabetes group (R2 = 25%) and with age and smoking in the control group (R2 = 46%). Skin autofluorescence was significantly higher in the type 2 diabetes group, with both micro- and macrovascular disease, compared with the group without complications and the group with only microvascular complications. CONCLUSIONS: This study confirms in a large group of type 2 diabetic patients that skin autofluorescence is higher compared with age-matched control subjects and is associated with the severity of diabetes-related complications. Skin autofluorescence reflecting vascular damage might be a rapid and helpful tool in the diabetes outpatient clinic for identifying diabetic patients who are at risk for developing complications.

Skin advanced glycation end products in HIV infection are increased and predictive of development of cardiovascular events.

OBJECTIVE: HIV-1 infection is associated with an increased cardiovascular disease (CVD) risk. Advanced glycation end products are formed as stable markers of glycaemic and oxidative stress. Skin autofluorescence (SAF) as marker of accumulated advanced glycation end products is increased and predictive of CVD events in diabetes mellitus, chronic kidney disease (CKD), and preexisting CVD. We determined SAF levels in HIV-1 infected patients, testing the hypothesis that SAF predicts CVD events in HIV infection. DESIGN: Single-centre prospective cohort study. METHODS: In 2010-2011, SAF was measured in 91 patients. Development of CVD events was monitored during a median follow-up of 4.8 years. SAF values of the patients were expressed as a ratio (rSAF) to expected SAF levels in age-matched healthy volunteers. RESULTS: Seventy-nine men and 12 women were included, mean age 47 years; 81 patients were on combination antiretroviral therapy. With a mean rSAF of 1.155, SAF levels in patients were 15.5% higher than predicted for their age (95% confidence interval, 10.0-20.0; P < 0.001). In multivariate regression analysis, rSAF was associated with nadir CD4 cell count less than 200 cells/µl (ß -0.274; P = 0.01), smoking (ß 0.240; P = 0.03), and men who have sex with men (MSM) (ß 0.202; P = 0.07). CVD events occurred in six patients (7%). In Cox regression analysis including age, SAF, smoking, diabetes, hypertension and CKD, SAF (P = 0.01), and (Wet Medisch-wetenschappelijk Onderzoek met mensen; WMO) CKD (P = 0.03) remained as independent predictors of CVD events. CONCLUSION: SAF is increased in HIV-infected patients, and related with smoking, low nadir CD4 cell count, and MSM. Larger studies are needed to confirm whether SAF is an independent predictor of CVD events.

Skin autofluorescence, a non-invasive biomarker for advanced glycation end products, is associated with the metabolic syndrome and its individual components.

BACKGROUND: The metabolic syndrome (MetS) comprises several cardiometabolic risk factors associated with increased risk for both type 2 diabetes and cardiovascular disease. Skin autofluorescence (SAF), a non-invasive biomarker of advanced glycation end products accumulation, is associated with cardiovascular complications in subjects with diabetes. The aim of the present study was to examine the association between SAF and the presence of MetS as well as its individual components in a general population. METHODS: For this cross-sectional analysis, we included 78,671 non-diabetic subjects between 18 and 80 years of age who participated in the LifeLines Cohort Study and had SAF measurement obtained non-invasively using the AGE Reader. MetS was defined according to the revised NCEP ATP III criteria. Students unpaired t test was used to test differences between groups. Both logistic and linear regression analyses were performed in order to test associations between the individual MetS components and SAF. RESULTS: Subjects with MetS had higher SAF (2.07 ± 0.45 arbitrary units, AU) compared to individuals without MetS (1.89 ± 0.42 AU) (p < 0.001). There was a positive association between the number of MetS components and higher SAF Z-scores (p < 0.001). Individuals in the highest SAF tertile had a higher presence of MetS (OR 2.61; 95% CI 2.48-2.75) and some of the individual components compared to subjects in the lowest SAF tertile. After correction for age, gender, creatinine clearance, HbA1c and smoking status, only elevated blood pressure and low HDL cholesterol remained significantly associated with higher SAF (p = 0.002 and p = 0.001 respectively). CONCLUSION: Skin autofluorescence was associated with the presence of MetS and some of its individual components. In addition, increasing SAF Z-scores were observed with a higher number of MetS components. Prospective studies are needed to establish whether SAF can be used as an (additional) screening tool to predict both cardiovascular disease and type 2 diabetes in high-risk populations.

The association between various smoking behaviors, cotinine biomarkers and skin autofluorescence, a marker for advanced glycation end product accumulation.

BACKGROUND: Skin autofluorescence, a biomarker for advanced glycation end products (AGEs) accumulation, has been shown to predict diabetes-related cardiovascular complications and is associated with several environmental and lifestyle factors. In the present study, we examined the association between various smoking behaviors and skin autofluorescence, as well as the association between several cotinine biomarkers and skin autofluorescence, using both epidemiological and metabolomics data. METHODS: In a cross-sectional study, we evaluated participants from the LifeLines Cohort Study and the Qatar Metabolomics Study on Diabetes (QMDiab). In the LifeLines Cohort Study smoking behavior and secondhand smoking were assessed in 8,905 individuals including 309 individuals (3.5%) with type 2 diabetes. In QMDiab, cotinine biomarkers were measured in saliva, plasma and urine in 364 individuals of whom 188 (51%) had type 2 diabetes. Skin autofluorescence was measured non-invasively in all participants using the AGE Reader. RESULTS: Skin autofluorescence levels increased with a higher number of hours being exposed to secondhand smoking. Skin autofluorescence levels of former smokers approached levels of never smokers after around 15 years of smoking cessation. Urinary cotinine N-oxide, a biomarker of nicotine exposure, was found to be positively associated with skin autofluorescence in the QMDiab study (p = 0.03). CONCLUSIONS: In the present study, we have demonstrated that secondhand smoking is associated with higher skin autofluorescence levels whereas smoking cessation has a beneficial effect on skin autofluorescence. Finally, urinary cotinine N-oxide might be used as an alternative way for questionnaires to examine the effect of (environmental) tobacco smoking on skin autofluorescence.