Skin Autofluorescence Is Associated with Endothelial Dysfunction in Uremic Subjects on Hemodialysis

Association between endothelial function and skin advanced glycation end-products (AGEs) accumulation in a sample of predominantly young and healthy adults

BACKGROUND

In populations with chronic disease, skin autofluorescence (SAF), a measure of long-term fluorescent advanced glycation end-products (AGEs) accumulation in body tissues, has been associated with vascular endothelial function, measured using flow-mediated dilation (FMD). The primary aim of this study was to quantify the relationship between endothelial function and tissue accumulation of AGEs in adults from the general population to determine whether SAF could be used as a marker to predict early impairment of the endothelium.

METHODS

A cross-sectional study was conducted with 125 participants (median age: 28.5 y, IQR: 24.4-36.0; 54% women). Endothelial function was measured by fasting FMD. Skin AGEs were measured as SAF using an AGE Reader. Participant anthropometry, blood pressure, and blood biomarkers were also measured. Associations were evaluated using multivariable regression analysis and were adjusted for significant covariates.

RESULTS

FMD was inversely correlated with SAF (ρ = -0.50, P < 0.001) and chronological age (ρ = -0.51, P < 0.001). In the multivariable analysis, SAF, chronological age, and male sex were independently associated with reduced FMD (B [95% CI]; -2.60 [-4.40, -0.80]; -0.10 [-0.16, -0.03]; 1.40 [0.14, 2.67], respectively), with the multivariable model adjusted R2 = 0.31, P < 0.001.

CONCLUSIONS

Higher skin AGE levels, as measured by SAF, were associated with lower FMD values, in a predominantly young, healthy population. Additionally, older age and male participants exhibited significantly lower FMD values, corresponding with compromised endothelial function. These results suggest that SAF, a simple and inexpensive marker, could be used to predict endothelial impairment before the emergence of any structural artery pathophysiology or classic cardiovascular disease risk markers.

TRIAL REGISTRATION

The study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12621000821897) and concurrently entered into the WHO International Clinical Trials Registry Platform under the same ID number.

Toxin Removal and Inflammatory State Modulation during Online Hemodiafiltration Using Two Different Dialyzers (TRIAD2 Study)

Uremic toxins play a pathological role in atherosclerosis and represent an important risk factor in dialysis patients. Online hemodiafiltration (HDF) has been introduced to improve the clearance of middle- and large-molecular-weight solutes (>500 Da) and has been associated with reduced cardiovascular mortality compared to standard hemodialysis. This non-randomized, open-label observational study will explore the efficacy of two dialyzers currently used for online HDF, a polysulfone-based high-flux membrane, and a cellulose triacetate membrane, in hemodialysis patients with signs of middle-molecule intoxication or intradialytic hypotension. In particular, the two filters will be evaluated for their ability in uremic toxin removal and modulation of inflammatory status. Sixteen subjects in standard chronic bicarbonate hemodialysis requiring a switch to online HDF in view of their clinical status will be enrolled and divided into two treatment arms, according to the previous history of hypersensitivity to polysulfone/polyethersulfone dialysis filters and hypersensitivity to drugs or other allergens. Group A will consist of 16 patients without a previous history of hypersensitivity and will be treated with a polysulfone filter (Helixone FX100), and group B, also consisting of 16 patients, with a previous history of hypersensitivity and will be treated with asymmetric triacetate (ATA; SOLACEA 21-H) dialyzer. Each patient will be followed for a period of 24 months, with monthly assessments of circulating middle-weight toxins and protein-bound toxins, markers of inflammation and oxidative stress, lymphocyte subsets, activated lymphocytes, and monocytes, cell apoptosis, the accumulation of advanced glycation end-products (AGEs), variations in arterial stiffens measured by pulse wave velocity (PWV), and mortality rate. The in vitro effect on endothelial cells of uremic serum collected from patients treated with the two different dialyzers will also be investigated to examine the changes in angiogenesis, cell migration, differentiation, apoptosis and proliferative potential, and gene and protein expression profile. The expected results will be a better awareness of the different effects of polysulfone gold-standard membrane for online HDF and the new ATA membrane on the removal of uremic toxins removal and inflammation due to blood-membrane interaction.

Serum and Tissue Levels of Advanced Glycation End Products and Risk of Mortality in Patients on Maintenance Hemodialysis

BACKGROUND

The relation of tissue and circulating advanced glycation end products (AGEs) with mortality in hemodialysis (HD) patients remains inconclusive. We aimed to investigate the association of serum AGEs (CML) and tissue AGEs estimated by skin autofluorescence (SAF) with all-cause and cardiovascular disease (CVD) mortality, and examine the possible modifiers for the association in HD patients with by far the largest sample size in any similar studies.

METHODS

A total of 1,634 HD patients were included from the China Cooperative Study on Dialysis (CCSD), a multicenter prospective cohort study. The primary and secondary outcomes were all-cause mortality and CVD mortality, respectively.

RESULTS

The median follow-up duration was 5.2 years. Overall, there was a positive relation of baseline SAF levels with the risk of all-cause mortality (per 1 AU increment, adjusted hazard ratio (HR), 1.30; 95% confidence interval (CI): 1.12, 1.50) and CVD mortality (per 1 AU increment, adjusted HR, 1.36; 95% CI: 1.14, 1.62). Moreover, a stronger positive association between baseline SAF (per 1 AU increment) and all-cause mortality was found in participants with shorter dialysis vintage, or lower C-reactive protein levels (Both p interactions <0.05). Nevertheless, there was no significant association between serum CML and the risk of mortality.

CONCLUSIONS

In patients undergoing long-term HD, baseline SAF, but not serum CML, was significantly associated with the risk of all-cause and CVD death.

Arterial endothelial function, carotid artery intima-media thickness and abdominal aortic calcification in diabetic and nondiabetic CKD stage 4-5 patients not on dialysis

AIMS

We aimed to study the effect of diabetes (DM) on endothelial dysfunction assessed by flow-mediated vasodilatation (FMD), carotid intima-media thickness (cIMT) and abdominal aortic calcification score (AAC) in chronic kidney disease (CKD) stage 4-5 patients not on dialysis.

METHODS

Altogether 199 non-dialysis CKD stage 4-5 patients enrolled in the Chronic Arterial Disease, quality of life and mortality in chronic KIDney injury (CADKID) study with plain lumbar radiograph for the assessment of AAC were included. Data on cIMT and FMD were available for 172 and 161 patients, respectively.

RESULTS

Median age was 65 (IQR 54-76) years, 88 (44.2%) patients had DM and median eGFR was 12 (IQR 10-14) ml/min/1.73 m² in the study. FMD [controls: 3.3(2.0-6.7)% vs. DM-patients: 4.3(1.3-6.6)%, p = 0.73] and cIMT [controls: 0.65(0.58-0.87)mm vs. DM-patients: 0.67(0.59-0.81)mm, p = 0.65], were similar between the groups. AAC was higher in patients with DM [controls: 5(1-9) vs. DM-patients: 7(2-13), p = 0.01]. The significant multivariate determinants for AAC were older age (β = 0.22, p < 0.0001), pulse pressure (β = 0.05, p < 0.0001), DM (β = 1.33, p = 0.04) and ProBNP (per µg/l β = 0.18, p = 0.0008). AAC and cIMT were associated with incident cardiovascular death independent of DM.

CONCLUSIONS

DM is associated with increased AAC but not increased cIMT or attenuated FMD in advanced CKD patients.

The association of non-invasive skin autofluorescence measurements with cardiovascular and all-cause mortality in hemodialysis patients: a meta-analysis

BACKGROUND

This systematic review and meta-analysis were aimed to study the association of tissue accumulation of advanced glycation end products (AGEs) measured as skin autofluorescence (SAF) with cardiovascular disease (CVD), cardiovascular mortality (CVM) and all-cause mortality (ACM) in hemodialysis (HD) patients.

METHODS

All major databases were searched for relevant studies reporting SAF in dialysis patients. Data for meta-analyses were extracted in the form of odds ratios (OR) and/or hazard ratios (HR) and the pooled overall outcomes were computed for the association of SAF with CVD, CVM, ACM in HD patients using either fixed or random effects meta-analysis based on the between-study heterogeneity. The sensitivity and meta-regression analyses were performed.

RESULTS

We included nine studies in this meta-analysis. The SAF levels were associated with higher risk for cardiovascular morbidity (pooled OR = 2.59, Z = 2.30, P = 0.02), cardiovascular (pooled HR = 3.03, Z = 3.13, P = 0.002) and overall mortalities (pooled HR = 2.23, Z = 6.30, P < 0.001) in HD patients.

CONCLUSION

In HD patients, the novel and non-invasive measurement of tissue AGEs as SAF levels could be useful for risk estimating the cardiovascular and all-cause mortalities.

Skin Autofluorescence as a Predictor of First Heart Failure Hospitalization in Patients With Heart Failure With Preserved Ejection Fraction

Background

An autofluorescence (AF) reader can be used to diagnose skin AF non-invasively by measuring local accumulation of advanced glycation end-products. A number of studies have investigated the relationships between skin AF and cardiovascular disease. However, data regarding the usefulness of skin AF as a predictor of chronic heart failure remain limited. This prospective study aimed to elucidate the usefulness of skin AF as a predictor of first heart failure (HF) hospitalization in patients with HF with preserved ejection fraction (HFpEF).

Methods

A total of 412 outpatients with HFpEF with no history of HF hospitalization were enrolled. Patients were assigned to either the low (group L; skin AF ≤ 2.9 arbitrary units (AU); n = 303) or the high (group H; skin AF ≥ 3.0 AU; n = 109) group according to optimal skin AF cut-off levels determined using receiver operating characteristic curves. Clinical parameters and the usefulness of skin AF as a predictor of first HF hospitalization were evaluated.

Results

The E/e' ratio as a marker of left ventricular diastolic function was significantly higher in group H patients than in group L patients at baseline (group H, 11.8 ± 3.8; group L, 10.6 ± 3.3; P = 0.002). During the 72.7-month follow-up period, 43 HF cases were hospitalized (group L, 15 cases; group H, 28 cases; P < 0.001, log-rank test). Multivariate Cox regression analyses revealed that group H exhibited a significantly higher risk of first HF hospitalization than did group L (hazard ratio, 2.26; 95% confidence interval, 1.21 - 3.52; P = 0.014).

Conclusions

The present study demonstrated that skin AF can predict the risk of first HF hospitalization in patients with HFpEF. Prospective studies, including intervention therapies, are required to validate our observations.

Spironolactone ameliorates endothelial dysfunction through inhibition of the AGE/RAGE axis in a chronic renal failure rat model

BACKGROUND

Spironolactone can improve endothelial dysfunction in the setting of heart failure and diabetes models. However, its beneficial effect in the cardiovascular system is not clear in the setting of non-diabetic renal failure. We conducted this study to investigate whether spironolactone can ameliorate endothelial dysfunction in a 5/6 nephrectomy model, and to determine the underlying mechanism.

METHODS

Twenty-four Sprague-Dawley rats were divided into four groups. A renal failure model was created using the 5/6 nephrectomy method. The four groups included: Sham-operation group (Group1), chronic kidney disease (CKD; Group2), CKD + ALT-711 (advanced glycation end products [AGEs] breaker; Group 3), and CKD + spironolactone group (Group4). Acetylcholine (Ach)-mediated vasodilatation responses were compared between the four groups. To investigate the underlying mechanism, we cultured human aortic endothelial cells (HAECs) for in-vitro assays. Differences between two groups were determined with the paired student's t test. Differences between three or more groups were determined through one-way analysis of variance (ANOVA) with post-hoc analysis with LSD method.

RESULTS

Compared with Group 1, Group 2 has a significantly impaired Ach-mediated vasodilatation response. Group 3 and 4 exhibited improved vasoreactivity responses. To determine the underlying mechanism, we performed an in-vitro study using cultured HAECs. We noted significant sirtuin-3 (SIRT3) protein downregulation, reduced phosphorylation of endothelial nitric oxide synthase at serine 1177 (p-eNOS), and increased intracellular oxidative stress in cultured HAECs treated with AGEs (200 μg/mL). These effects were counter-regulated when cultured HAECs were pretreated with spironolactone (10 μM). Furthermore, the increased p-eNOS production by spironolactone was abrogated when the HAECs were pretreated with tenolvin (1 μM), a SIRT3 inhibitor.

CONCLUSIONS

Spironolactone could ameliorate endothelial dysfunction in a 5/6 nephrectomy renal failure model through AGEs/Receptor for AGEs (RAGEs) axis inhibition, SIRT3 upregulation, and nicotinamide adenine dinucleotide phosphate oxidase-2 (NOX-2) and its associated intracellular oxidative stress attenuation.

Relations of advanced glycation endproducts and dicarbonyls with endothelial dysfunction and low-grade inflammation in individuals with end-stage renal disease in the transition to renal replacement therapy: A cross-sectional observational study

Background

Cardiovascular disease (CVD) related mortality and morbidity are high in end-stage renal disease (ESRD). The pathophysiology of CVD in ESRD may involve non-traditional CVD risk factors, such as accumulation of advanced glycation endproducts (AGEs), dicarbonyls, endothelial dysfunction (ED) and low-grade inflammation (LGI). However, detailed data on the relation of AGEs and dicarbonyls with ED and LGI in ESRD are limited.

Methods

We examined cross-sectional Spearman’s rank correlations of AGEs and dicarbonyls with serum biomarkers of ED and LGI in 43 individuals with chronic kidney disease (CKD) stage 5 not on dialysis (CKD5-ND). Free and protein-bound serum AGEs (N^∈-(carboxymethyl)lysine (CML), N^∈-(carboxyethyl)lysine (CEL), N_δ-(5-hydro-5-methyl-4-imidazolon-2-yl)ornithine (MG-H1)) and serum dicarbonyls (glyoxal, methylglyoxal, 3-deoxyglucosone) were analyzed with tandem mass spectrometry, and tissue AGE accumulation was estimated by skin autofluorescence (SAF). Further, serum biomarkers of ED and LGI included sVCAM-1, sE-selectin, sP-selectin, sThrombomodulin, sICAM-1, sICAM-3, hs-CRP, SAA, IL-6, IL-8 and TNF-α.

Results

After adjustment for age, sex and diabetes status, protein-bound CML was positively correlated with sVCAM-1; free CEL with sVCAM-1 and sThrombomodulin; glyoxal with sThrombomodulin; and methylglyoxal with sVCAM-1 (correlation coefficients ranged from 0.36 to 0.44). In addition, free CML was positively correlated with SAA; protein-bound CML with IL-6; free CEL with hs-CRP, SAA and IL-6; free MG-H1 with SAA; protein-bound MG-H1 with IL-6; and MGO with hs-CRP and IL-6 (correlation coefficients ranged from 0.33 to 0.38). Additional adjustment for eGFR attenuated partial correlations of serum AGEs and serum dicarbonyls with biomarkers of ED and LGI.

Conclusions

In individuals with CKD5-ND, higher levels of serum AGEs and serum dicarbonyls were related to biomarkers of ED and LGI after adjustment for age, sex and diabetes mellitus. Correlations were attenuated by eGFR, suggesting that eGFR confounds and/or mediates the relation of serum AGEs and dicarbonyls with ED and LGI.

Relationships Between Skin Autofluorescence and Cardio-Ankle Vascular Index in Japanese Male Patients With Metabolic Syndrome

Background

An autofluorescence (AF) reader can be used to noninvasively measure tissues that accumulated advanced glycation end-products to diagnose skin AF. This study aimed to clarify the clinical significance of skin AF as a risk factor for cardiovascular disease in Japanese male patients with metabolic syndrome using the cardio-ankle vascular index (CAVI) as a marker of arterial function.

Methods

This cross-sectional study enrolled 261 Japanese male patients with metabolic syndrome without history of cardiovascular disease (mean age, 58 ± 7 years (mean ± standard deviation)). Associations between skin AF and various clinical parameters including CAVI were examined.

Results

Skin AF was significantly positively correlated with CAVI (r = 0.40, P < 0.001). Furthermore, multiple regression analyses revealed that skin AF (β = 0.18, P = 0.002) was selected as an independent subordinate factor for CAVI. Meanwhile, homeostatic model assessment of insulin resistance (HOMA-IR) as a marker of insulin resistance, smoking habits and high-sensitivity C-reactive protein as an inflammation marker were independent variables for either CAVI or skin AF as a subordinate factor. According to the receiver-operating characteristic curve analysis and results of previous reports that determined CAVI of ≥ 9.0 as a diagnostic criterion for vascular failure, skin AF of > 2.7 arbitrary unit is the optimal cut-off point for discriminating high CAVI (area under the curve = 0.718, P < 0.001).

Conclusion

Findings in this study indicate that skin AF may be an important risk factor of cardiovascular disease in Japanese male patients with metabolic syndrome. In addition, the risk value of skin AF was considered as higher than 2.7 arbitrary unit. Further investigations in a large number of prospective studies, including intervention therapies, are required to validate the results in this study.

Skin autofluorescence is associated with rapid renal function decline in subjects at increased risk of coronary artery disease

Skin autofluorescence (AF) has been validated as a tool for estimating tissue advanced glycation end products (AGEs) accumulation and predicting long-term cardiovascular outcomes. However, whether measurements of skin AF could predict renal function decline remains controversial. From April, 2014 to April, 2015, we enrolled 245 subjects with at least two conventional risk factors for coronary artery disease (CAD). All were measured for body height and weight, blood pressure, plasma creatinine level, and skin AF at the start of the study. Baseline demographics and laboratory tests data were obtained by chart reviews and patient interviews. Serial plasma creatinine levels were followed regularly every 6-12 months for 2 years. In a stepwise multivariate linear regression analysis, skin AF, was an independent factor for predicting the relative renal function decline rate after adjustment of multiple covariates (ß = -0.036±0.016; p = 0.03). Subgroups analysis revealed that skin AF was a significant factor for relative renal function decline rate in subgroups of age < 65 years (ß = -0.068±0.024; p = 0.02), male sex (ß = -0.053±0.016; p< 0.01), body mass index≧25 Kg/m2(ß = -0.042±0.021; p = 0.04), and estimated glomerular filtration rate ≥ 60 ml/min/1.73m2(ß = -0.043±0.020; p = 0.04). However, only an interaction between skin AF and age attained significance (p for interaction = 0.04). Skin AF is a useful predictor for renal function decline in patients at increased risk of CAD.

Association between Subclinical Atherosclerosis Markers and the Level of Accumulated Advanced Glycation End-Products in the Skin of Patients with Diabetes

Aim: The level of accumulated advanced glycation end-products (AGEs) in the skin has been shown to predict the risk of complications in patients with diabetes mellitus (DM). Recently, the level of accumulated fluorescent AGEs in the skin has become measurable as skin autofluorescence (skin AF) using a non-invasive apparatus, autofluorescence reader. The purpose of this study was to evaluate the association between skin AF and the subclinical atherosclerosis markers, especially endothelial dysfunction, in patients with DM.

Methods: We enrolled 140 Japanese subjects with DM who attended Osaka University Hospital, and measured the skin level of AGEs by skin AF and three subclinical atherosclerosis markers: endothelial function by flow-mediated vasodilation, FMD; carotid intima-media thickness, IMT; and brachial-ankle pulse wave velocity, baPWV.

Results: FMD was significantly associated with skin AF (r = −0.259, p = 0.002). Furthermore, a stepwise multivariate regression analysis revealed that skin AF was an independent determinant of FMD (β = −0.180, p = 0.038). Although there were significant associations between skin AF and maximum carotid intima-media thickness (max-IMT)(r = 0.298, p < 0.001) as well as baPWV (r = 0.284, p = 0.001) in univariate analysis, skin AF was not an independent determinant of either carotid max-IMT or baPWV after adjustment for conventional cardiovascular risk factors. Receiver-operating characteristic curve analysis revealed that skin AF can identify the subjects whose FMD, max-IMT, and baPWV were completely within the normal range (C-statistics, 0.73; 95% confidence interval, 0.61–0.84; p < 0.001).

Conclusions: Skin AF was independently associated with FMD as an indicator of endothelial dysfunction, and can be utilized as a screening marker of atherosclerosis in Japanese patients with DM.

Critical Appraisal of Advanced Glycation End Products (AGEs) and Circulating Soluble Receptors for Advanced Glycation End Products (sRAGE) as a Predictive Biomarkers for Cardiovascular Disease in Hemodialysis Patients

The interaction of advanced glycation end products (AGE) and their receptors promote vascular complications of diabetes in hemodialysis (HD) patients. The soluble form of the receptor for the advanced glycation end-products (sRAGE) has been studied as a vascular biomarker in various diseases with controversial results. Our aim was to evaluate the association of the serum levels of the AGEs and their receptor sRAGE with cardiovascular disease (CVD) and the cardiovascular risk factors among HD patients. There were 130 HD patients and 80 age and gender matched control subjects were involved; 31.5% of the HD group were diabetic, which was an underlying cause of renal impairment; 36.1% had CVD, which was comprising 44.7% of diabetics and 55.3% of non-diabetic patients. The AGEs and sRAGE were assessed by enzyme linked immunosorbent assay (ELISA). In addition, the lipid profile, glycemic indices, pre-dialysis renal function tests, and hemoglobin % (Hb) were evaluated. The results show that the circulating AGEs and sRAGE levels were significantly higher in the HD patients. Those with underlying diabetes displayed higher sRAGE levels, which were positively correlated with hyperglycemia, HbA1C, and total cholesterol (TC). The HD patients with an increased serum sRAGE exhibited more cardiovascular risk factors (hypercholesterolemia and anemia) with a high prevalence of CVD. Using a linear regression analysis, we found a significant association of sRAGE with CVD and TC among HD patients, regardless of whether associating diabetes was an underlying cause of renal impairment. Overall, the HD patients displayed significantly higher serum AGEs with a concomitant increase in the circulating sRAGE levels, mainly in the diabetic HD, which were significantly associated with the CVD (independent predictors) and CV risk factors (hypercholesterolemia), mainly sRAGEs, regardless of the underlying diabetes mellitus. This highlights the prognostic role of AGEs and sRAGE in HD patients regardless of underlying cause in order to predict the risk for CVD.

Clinical Significance of Skin Autofluorescence in Patients With Type 2 Diabetes Mellitus With Chronic Heart Failure

Background

Recent clinical studies have shown that skin autofluorescence (AF) levels are significantly associated with diabetic complications. In contrast, data regarding the relationships between skin AF and chronic heart failure (CHF) are limited. The aim of this study was to clarify the clinical significance of skin AF in patients with type 2 diabetes mellitus (DM) with CHF.

Methods

This cross-sectional study enrolled 257 outpatients with type 2 DM with CHF who were treated medically (96 men and 161 women; mean age, 79 ± 7 years). Associations between skin AF and various clinical parameters were examined.

Results

Incidence of skin AF in patients with a history of hospitalization due to HF was significantly higher than in those without a history of hospitalization due to HF (3.0 ± 0.5 AU vs. 2.7 ± 0.5 AU, respectively, P < 0.001). Significant positive correlations were found between skin AF and various clinical parameters, such as E/e′ as a maker of left ventricular diastolic function (r = 0.30, P < 0.001), high-sensitivity cardiac troponin T levels as a marker of myocardial injury (r = 0.45, P < 0.001), reactive oxygen metabolite levels as an oxidative stress marker (r = 0.31, P < 0.001), and cardio-ankle vascular index as a marker of arterial function (r = 0.38, P < 0.001). Furthermore, multiple regression analyses showed that these clinical parameters (E/e′ (β = 0.25, P < 0.001)), high-sensitivity cardiac troponin T levels (β = 0.30, P < 0.001), cardio-ankle vascular index (β = 0.21, P < 0.001), reactive oxygen metabolite levels (β = 0.15, P < 0.01), and a history of hospitalization due to HF (β = 0.23, P < 0.001) were independent variables when skin AF was used as a subordinate factor.

Conclusion

The findings of this study showed that skin AF may be a determining factor for prognosis in patients with type 2 DM with CHF. Further investigations in a large prospective study, including intervention therapies, are required to validate the results of this study.

Sevelamer reduces endothelial inflammatory response to advanced glycation end products

Background

Advanced glycation end products (AGEs) have been related to the pathogenesis of cardiovascular diseases (CVD), chronic kidney disease (CKD) and diabetes mellitus. We sought to investigate the binding capacity of sevelamer to both AGEs and uremic serum in vitro and then test this pharmaceutical effect as a potential vascular anti-inflammatory strategy.

Methods

AGEs were prepared by albumin glycation and characterized by absorbance and electrophoresis. Human endothelial cells were incubated in culture media containing AGEs and uremic serum with or without sevelamer. Receptor for advanced glycation end product (RAGE) expression was evaluated through immunocytochemistry and western blot to explore the interactions between AGEs and the endothelium. Inflammatory and endothelial dysfunction biomarkers, such as interleukin 6 (IL-6) and IL-8, monocyte chemoattractant protein-1 (MCP-1), plasminogen activator inhibitor-1 (PAI-1) and serum amyloid A (SAA) were also measured in cell supernatant. The chemotactic property of the supernatant was evaluated.

Results

AGEs significantly induced the expression of RAGE, inflammatory and endothelial activation biomarkers [IL-6, (P < 0.005); IL-8, MCP-1, PAI-1 and SAA (P < 0.001)] and monocyte chemotaxis as compared with controls. In addition, AGEs increased the levels of inflammatory biomarkers, which were observed after 6 h of endothelial cell incubation with uremic serum [IL-6 (P < 0.001) IL-8, MCP-1 and PAI-1 (P < 0.05)]. On the other hand, after 6 h of endothelial cell treatment with sevelamer, RAGE expression (P < 0.05) and levels of inflammatory biomarkers [IL-6 and IL-8 (P < 0.001), MCP-1 (P < 0.01), PAI-1 and SAA (P < 0.005)] significantly decreased compared with the AGEs/uremic serum treatment alone.

Conclusions

Sevelamer decreased both endothelial expression of RAGE and endothelial dysfunction biomarkers, induced by AGEs, and uremic serum. Further studies are necessary for a better understanding of the potential protective role of sevelamer on uremic serum and AGEs-mediated endothelial dysfunction.

Relationships between the arterial velocity pulse index as a novel marker of atherosclerosis and biomarkers of cardiac or renal condition in patients with type 2 diabetes mellitus

BACKGROUND

The arterial velocity pulse index (AVI) has been explored as a novel marker of atherosclerosis using pulse wave analysis in the clinical setting. The aim of this study was to clarify the relationships between the AVI and biomarkers of cardiac or renal condition in patients with type 2 diabetes mellitus.

METHODS

In total, 301 outpatients with type 2 diabetes mellitus (116 males and 185 females; mean age ± standard deviation: 63 ± 12 years) without a history of cardiovascular events were enrolled in this study. The AVI and biomarkers of cardiac or renal condition were measured using a commercial device, and the relationships between the AVI and the biomarkers were examined.

RESULTS

The AVI was significantly associated with biomarkers of cardiac condition such as the blood levels of brain natriuretic peptide (r = 0.29, P < 0.001) and high-sensitivity cardiac troponin T (hs-cTnT) (r = 0.48, P < 0.001). The AVI was also significantly associated with biomarkers of renal condition such as the estimated glomerular filtration rate (r = -0.22, P < 0.001) and urinary albumin excretion (r = 0.42, P < 0.001). Multiple regression analysis revealed that hs-cTnT and urinary albumin excretion were independent variables that were correlated with the AVI when it was used as a subordinate factor.

CONCLUSION

The results of this study indicate that the AVI is significantly associated with hs-cTnT and urinary albumin excretion in patients with type 2 diabetes mellitus.

Electronegative low-density lipoprotein increases the risk of ischemic lower-extremity peripheral artery disease in uremia patients on maintenance hemodialysis

Electronegative low-density lipoprotein (LDL) has been shown to increase coronary artery disease risk in hemodialysis patients, but its effect on the risk of peripheral artery disease (PAD) remains unclear. We separated plasma LDL from 90 uremia patients undergoing hemodialysis into 5 subfractions (L1-L5) according to charge by using fast-protein liquid chromatography with an anion-exchange column and examined the distribution of L5-the most electronegative LDL subfraction-in total LDL (i.e. L5%). During a 5-year period, we followed up with these patients until the occurrence of ischemic lower-extremity PAD. During the follow-up period, ischemic lower-extremity PAD developed in 24.4% of hemodialysis patients. L5% was higher in hemodialysis patients in whom ischemic lower-extremity PAD occurred (3.03% [IQR, 2.36-4.54], n = 22) than in hemodialysis patients in whom PAD did not occur (1.13% [IQR, 0.90-1.83], n = 68) (p < 0.001). Furthermore, L5% significantly increased the adjusted hazard ratio of ischemic lower-extremity PAD (1.54 [95% CI, 1.14-2.10]) (p = 0.005). Flow-mediated dilation was negatively associated with L5% (p < 0.001). Additionally, in vivo experiments from mice showed that L5 compromised endothelium-dependent vascular relaxation through a nitric oxide-related mechanism. Our findings indicate that increased L5% may be associated with the occurrence of ischemic lower-extremity PAD in hemodialysis patients.

Skin Autofluorescence and Subclinical Atherosclerosis in Mild to Moderate Chronic Kidney Disease: A Case-Control Study

Advanced glycation end-products (AGEs) are increased and predict mortality in patients with chronic kidney disease (CKD) who are undergoing hemodialysis, irrespective of the presence of type 2 diabetes. However, little information exits about the relationship between AGEs and subclinical atherosclerosis at the early stages of CKD. A case-control study was performed including 87 patients with mild-to-moderate stages of CKD (glomerular filtration rate from 89 to 30 ml/min/per 1.73m²) and 87 non-diabetic non-CKD subjects matched by age, gender, body mass index, and waist circumference. Skin autofluorescence (AF), a non-invasive assessment of AGEs, was measured. The presence of atheromatous disease in carotid and femoral arteries was evaluated using vascular ultrasound, and vascular age and SCORE risk were estimated. Patients with mild-to-moderate stages of CKD showed an increase in skin AF compared with control subjects (2.5±0.6 vs. 2.2±0.4 AU, p<0.001). A skin AF value >2.0 AU was accompanied by a 3-fold increased risk of detecting the presence of an atheromathous plaque (OR 3.0, 95% CI 1.4–6.5, p = 0.006). When vascular age was assessed through skin AF, subjects with CKD were almost 12 years older than control subjects (70.3±25.5 vs. 58.5±20.2 years, p = 0.001). Skin AF was negatively correlated with glomerular filtration rate (r = -0.354, p<0.001) and LDL-cholesterol (r = -0.269, p = 0.001), and positively correlated with age (r = 0.472, p<0.001), pulse pressure (r = 0.238, p = 0.002), and SCORE risk (r = 0.451, p<0.001). A stepwise multivariate regression analysis showed that age and glomerular filtration rate independently predicted skin AF (R² = 0.289, p<0.001). Skin AF is elevated in patients with mild-to-moderate CKD compared with control subjects. This finding may be independently associated with the glomerular filtration rate and the presence of subclinical atheromatous disease. Therefore, the use of skin AF may help to accurately evaluate the real cardiovascular risk at the early stages of CKD.

Skin autofluorescence is associated with inappropriate left ventricular mass and diastolic dysfunction in subjects at risk for cardiovascular disease

Background

Enhanced advanced glycation end products deposition within myocardial tissue may cause diastolic dysfunction. However, whether this is related to left ventricular hypertrophy or inappropriate left ventricular mass remains unclear.

Methods

We prospectively enrolled 139 subjects at risk for cardiovascular diseases. We used echocardiography for measurements of left ventricular mass and cardiac systolic and diastolic functional parameters. An advanced glycation end product reader was applied for measurements of skin autofluorescence values. Comparisons of left ventricular mass and echocardiographic parameters between the higher and lower skin autofluorescence groups were analyzed.

Results

Compared with the lower skin autofluorescence group, left ventricular mass index and the ratio of observed left ventricular mass/predicted left ventricular mass (oLVM/pLVM) was significantly higher in the higher skin autofluorescence group (61.22 ± 17.76 vs. 47.72 ± 11.62, P < 0.01, 1.62 ± 0.38 vs. 1.21 ± 0.21, P < 0.01). After adjustment for potential confounding factors, skin autofluorescence was an independent factor for left ventricular mass index (β = 0.32, P < 0.01) and the ratio of oLVM/pLVM (β = 0.41, P < 0.01). Skin autofluorescence ≥2.35 arbitrary unit predicted left ventricular hypertrophy at a sensitivity of 58.8%, and a specificity of 73.0% (P < 0.01). Skin autofluorescence ≥2.25 arbitrary unit predicted inappropriate left ventricular mass at a sensitivity of 71.1%, and a specificity of 83.9% (P < 0.01). Skin autofluorescence was positively correlated with E/E′, an indicator for diastolic dysfunction (r = 0.21, P = 0.01).

Conclusions

Skin autofluorescence is a useful tool for detecting left ventricular hypertrophy, inappropriate left ventricular mass and diastolic dysfunction.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-017-0495-9) contains supplementary material, which is available to authorized users.