Plasma glycated albumin level and atherosclerosis: Results from the Kyushu and Okinawa Population Study (KOPS)

Clinical effect of roxadustat vs. erythropoietin in non-dialysis CKD with diabetes: a single center propensity score matching analysis

PURPOSE

Renal anemia is a common complication of chronic kidney disease. Currently, recombinant human erythropoietin and roxadustat are the main treatments. In China, diabetic kidney disease is the primary cause of chronic kidney disease. However, high-quality evidence on the efficacy of roxadustat in patients with non-dialysis-dependent chronic kidney disease and diabetes mellitus is scarce. This study aimed to assess the clinical effect of roxadustat in such patients.

METHODS

Patients with non-dialysis-dependent anemia and diabetes mellitus who received roxadustat or recombinant human erythropoietin for ≥ 4 weeks were enrolled. We compared baseline characteristics, including age, gender, hypertension, and hemoglobin level, and then employed a 1:3 ratio propensity score matching. The primary efficacy outcomes were changes in hemoglobin levels. After propensity score matching, 212 patients were analyzed, including the roxadustat (n = 53) and recombinant human erythropoietin (n = 159) groups. Baseline characteristics were comparable, including hemoglobin level, estimated glomerular filtration rate, and glycated hemoglobin A1c (p > 0.05).

RESULTS

After 4, 12, and 24 weeks of treatment, the median hemoglobin levels in the roxadustat group were 97.5 g/L, 104 g/L, and 106.5 g/L, respectively, significantly surpassing the corresponding levels in the recombinant human erythropoietin group at 91 g/L, 94.5 g/L, and 94.5 g/L (p = 0.002, p = 0.025, p = 0.006, respectively). Additionally, subgroup analysis demonstrated better treatment efficacy of roxadustat patients with elevated high-sensitivity C-reactive protein and low albumin levels.

CONCLUSION

In Chinese patients with anemia and diabetes not on dialysis, roxadustat efficiently and rapidly improved and maintained hemoglobin levels unaffected by elevated high-sensitivity C-reactive protein and low albumin levels.

Serum glycated albumin as good biomarker for predicting type 2 diabetes: A retrospective cohort study of China National Diabetes and Metabolic Disorders Survey

AIMS

Glycated albumin (GA) is a biomarker for short-term (2-3 weeks) glycaemic control. However, the predictive utility of GA for diabetes and prediabetes is largely uncharacterised. We aimed to investigate the relationships of baseline serum GA levels with incident diabetes and prediabetes.

METHODS

This was a longitudinal cohort study involving 516 subjects without diabetes or prediabetes at baseline. Blood glucose levels were observed during follow-up. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using COX proportional hazard models. Receiver operating characteristic curves and areas under the curves (AUCs) were used to evaluate the discriminating abilities of glycaemic biomarkers and prediction models.

RESULTS

During a 9-year follow-up, 51 individuals (9.88%) developed diabetes and 92 (17.83%) prediabetes. Unadjusted HRs (95% CI) for both diabetes and prediabetes increased proportionally with increasing GA levels in a dose-response manner. Multivariable-adjusted HRs (95% CI) for diabetes were significantly elevated from 1.0 (reference) to 5.58 (1.86-16.74). However, the trend was no longer significant for prediabetes after multivariable adjustment. AUCs for GA, fasting blood glucose (FBG) and 2-h postprandial blood glucose (2h-PBG) for predicting diabetes were 0.698, 0.655 and 0.725, respectively. The AUCs for GA had no significant differences compared with those for FBG (p = 0.376) and 2h-PBG (p = 0.552). Replacing FBG or 2h-PBG or both with GA in diabetes prediction models made no significant changes to the AUCs of the models.

CONCLUSIONS

GA is of good prognostic utility in predicting diabetes. However, GA may not be a useful biomarker for predicting prediabetes.

Oxidized Albumin as a Mediator of Kidney Disease

Renal diseases are a global health concern, and nearly 24% of kidney disease patients are overweight or obese. Particularly, increased body mass index has been correlated with oxidative stress and urinary albumin excretion in kidney disease patients, also contributing to increased cardiovascular risk. Albumin is the main plasma protein and is able to partially cross the glomerular filtration barrier, being reabsorbed mainly by the proximal tubule through different mechanisms. However, it has been demonstrated that albumin suffers different posttranslational modifications, including oxidation, which appears to be tightly linked to kidney damage progression and is increased in obese patients. Plasma-oxidized albumin levels correlate with a decrease in estimated glomerular filtration rate and an increase in blood urea nitrogen in patients with chronic kidney disease. Moreover, oxidized albumin in kidney disease patients is independently correlated with higher plasma levels of transforming growth factor beta (TGF-β1), tumor necrosis factor (TNF-α), and interleukin (IL)-1β and IL-6. In addition, oxidized albumin exerts a direct effect on neutrophils by augmenting the levels of neutrophil gelatinase-associated lipocalin, a well-accepted biomarker for renal damage in patients and in different experimental settings. Moreover, it has been suggested that albumin oxidation occurs at early stages of chronic kidney disease, accelerating the patient requirements for dialytic treatment during disease progression. In this review, we summarize the evidence supporting the role of overweight- and obesity-induced oxidative stress as a critical factor for the progression of renal disease and cardiovascular morbimortality through albumin oxidation.

Recent Updates and Advances in the Use of Glycated Albumin for the Diagnosis and Monitoring of Diabetes and Renal, Cerebro- and Cardio-Metabolic Diseases

Diabetes mellitus is a heterogeneous and dysmetabolic chronic disease in which the laboratory plays a fundamental role, from diagnosis to monitoring therapy and studying complications. Early diagnosis and good glycemic control should start as early as possible to delay and prevent metabolic and cardio-vascular complications secondary to this disease. Glycated hemoglobin is currently used as the reference parameter. The accuracy of the glycated hemoglobin dosage may be compromised in subjects suffering from chronic renal failure and terminal nephropathy, affected by the reduction in the survival of erythrocytes, with consequent decrease in the time available for glucose to attach to the hemoglobin. In the presence of these renal comorbidities as well as hemoglobinopathies and pregnancy, glycated hemoglobin is not reliable. In such conditions, dosage of glycated albumin can help. Glycated albumin is not only useful for short-term diagnosis and monitoring but predicts the risk of diabetes, even in the presence of euglycemia. This protein is modified in subjects who do not yet have a glycemic alteration but, as a predictive factor, heralds the risk of diabetic disease. This review summarizes the importance of glycated albumin as a biomarker for predicting and stratifying the cardiovascular risk linked to multiorgan metabolic alterations.

Results of a Study Comparing Glycated Albumin to Other Glycemic Indices

CONTEXT

Intermediate-term glycemic control metrics fulfill a need for measures beyond hemoglobin A1C.

OBJECTIVE

Compare glycated albumin (GA), a 14-day blood glucose measure, with other glycemic indices.

DESIGN

24-week prospective study of assay performance.

SETTING

8 US clinics.

PARTICIPANTS

Subjects with type 1 (n = 73) and type 2 diabetes (n = 77) undergoing changes to improve glycemic control (n = 98) or with stable diabetes therapy (n = 52).

INTERVENTIONS

GA, fructosamine, and A1C measured at prespecified intervals. Mean blood glucose (MBG) calculated using weekly self-monitored blood glucose profiles.

MAIN OUTCOME MEASURES

Primary: Pearson correlation between GA and fructosamine. Secondary: magnitude (Spearman correlation) and direction (Kendall correlation) of change of glycemic indices in the first 3 months after a change in diabetes management.

RESULTS

GA was more concordant (60.8%) with changes in MBG than fructosamine (55.5%) or A1C (45.5%). Across all subjects and visits, the GA Pearson correlation with fructosamine was 0.920. Pearson correlations with A1C were 0.655 for GA and 0.515 for fructosamine (P < .001) and with MBG were 0.590 and 0.454, respectively (P < .001). At the individual subject level, Pearson correlations with both A1C and MBG were higher for GA than for fructosamine in 56% of subjects; only 4% of subjects had higher fructosamine correlations with A1C and MBG. GA had a higher Pearson correlation with A1C and MBG in 82% and 70% of subjects, respectively.

CONCLUSIONS

Compared with fructosamine, GA correlates significantly better with both short-term MBG and long-term A1C and may be more useful than fructosamine in clinical situations requiring monitoring of intermediate-term glycemic control (NCT02489773).

Glycated Serum Protein Genetics and Pleiotropy with Cardiometabolic Risk Factors

Measurements of fasting glucose (FG) or glycated hemoglobin A1c (HbA1c) are two clinically approved approaches commonly used to determine glycemia, both of which are influenced by genetic factors. Obtaining accurate measurements of FG or HbA1c is not without its challenges, though. Measuring glycated serum protein (GSP) offers an alternative approach for assessing glycemia. The aim of this study was to estimate the heritability of GSP and GSP expressed as a percentage of total serum albumin (%GA) using a variance component approach and localize genomic regions (QTLs) that harbor genes likely to influence GSP and %GA trait variation in a large extended multigenerational pedigree from Jiri, Nepal (n = 1,800). We also performed quantitative bivariate analyses to assess the relationship between GSP or %GA and several cardiometabolic traits. Additive genetic effects significantly influence variation in GSP and %GA levels (p values: 1.15 × 10^-5 and 3.39 × 10^-5, respectively). We localized a significant (LOD score = 3.18) and novel GSP QTL on chromosome 11q, which has been previously linked to type 2 diabetes. Two common (MAF > 0.4) SNPs within the chromosome 11 QTL were associated with GSP (adjusted pvalue < 5.87 × 10^-5): an intronic variant (rs10790184) in the DSCAML1 gene and a 3'UTR variant (rs8258) in the CEP164 gene. Significant positive correlations were observed between GSP or %GA and blood pressure, and lipid traits (p values: 0.0062 to 1.78 × 10^-9). A significant negative correlation was observed between %GA and HDL cholesterol (p = 1.12 × 10^-5). GSP is influenced by genetic factors and can be used to assess glycemia and diabetes risk. Thus, GSP measurements can facilitate glycemic studies when accurate FG and/or HbA1c measurements are difficult to obtain. GSP can also be measured from frozen blood (serum) samples, which allows the prospect of retrospective glycemic studies using archived samples.

Association of the Serum Endostatin Level, Renal Function, and Carotid Atherosclerosis of Healthy Residents of Japan: Results from the Kyushu and Okinawa Population Study (KOPS)

Aim: To analyze associations among the serum endostatin level, renal function, and carotid atherosclerosis of healthy residents of Japan.

Methods: Among 1,057 Japanese residents who attended free public physical examinations between 2010 and 2011, we evaluated the data of 648 healthy residents (200 men and 448 women, age 24 to 84 years) for whom the serum endostatin level and common carotid intima-media thickness (IMT) were measured. Renal function was assessed by estimated glomerular filtration rate (eGFR). Multiple linear regression analysis was done to determine the association of eGFR and serum endostatin level after adjustment for known covariates. Mediation analysis was done using Baron and Kenny's regression approach.

Results: The median endostatin level was 63.7 ng/mL (interquartile range: 49.7–93.2). The mean eGFR was 78.4 ± 14.8 mL/min/1.73m². Univariate analysis showed that age (r = −0.37, P < 0.01), non current smoking (85.8 ± 13.0 vs. 77.5 ± 14.8 mL/min/1.73 m², P < 0.01), hemoglobin A1c (r = −0.08, P = 0.05), low-density lipoprotein-cholesterol (r = −0.13, P < 0.01), uric acid (r = −0.15, P < 0.01), carotid IMT (r = −0.11, P < 0.01), and log-transformed endostatin (r = −0.36, P < 0.01) were significantly associated with eGFR. In multiple linear regression analysis, log-transformed endostatin was significantly associated with eGFR (beta = −0.24, P < 0.01). While, carotid IMT was no longer significant. Mediation analysis showed serum endostatin level to be a mediator in the association between carotid IMT and eGFR.

Conclusions: The association between carotid IMT and eGFR is mediated by the serum endostatin level of healthy individuals.

Alternate glycemic markers reflect glycemic variability in continuous glucose monitoring in youth with prediabetes and type 2 diabetes

OBJECTIVE

To determine whether the alternate glycemic markers, fructosamine (FA), glycated albumin (GA), and 1,5-anhydroglucitol (1,5AG), predict glycemic variability captured by continuous glucose monitoring (CGM) in obese youth with prediabetes and type 2 diabetes (T2D).

STUDY DESIGN

Youth with BMI ≥85th%ile, 10-18 years, had collection of fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), FA, GA, and 1,5AG and 72 hours of CGM. Participants with HbA1c ≥5.7% were included. Relationships between glycemic markers and CGM variables were determined with Spearman correlation coefficients. Linear models were used to examine the association between alternate markers and CGM measures of glycemic variability-standard deviation (SD) and mean amplitude of glycemic excursions (MAGE)-after controlling for HbA1c.

RESULTS

Total n = 56; Median (25th%ile, 75th%ile) age = 14.3 years (12.5, 15.9), 32% male, 64% Hispanic, 20% black, 13% white, HbA1c = 5.9% (5.8, 6.3), FA=211 mmol/L (200, 226), GA= 12% (11%, 12%), and 1,5AG = 22mcg/mL (19, 26). HbA1c correlated with average sensor glucose, AUC, SD, MAGE, and %time > 140 mg/dL. FA and GA correlated with average and peak sensor glucose, %time >140 and >200 mg/dL, and MAGE. GA also correlated with SD and AUC180. 1,5AG correlated with peak glucose, AUC180, SD, and MAGE. After adjusting for HbA1c, all 3 markers independently predicted MAGE; FA and GA independently predicted SD.

CONCLUSIONS

Alternate glycemic markers predict glycemic variability as measured by CGM in youth with prediabetes and T2D. After adjusting for HbA1c, these alternate markers continued to predict components of glycemic variability detected by CGM.

Correlation between Thyroid Stimulating Hormone and Renal Function in Euthyroid Residents of Japan: Results from the Kyushu and Okinawa Population Study (KOPS)

Aim: The present large-scale Japanese population study was performed to evaluate the relation between the serum thyroid stimulating hormone (TSH) level and renal function.

Methods: Out of 1,374 residents who participated in a free public physical examination between 2010 and 2011, we evaluated the data of 888 participants for whom the serum TSH level and estimated glomerular filtration rate (eGFR) were successfully measured. The participants were categorized into three groups based on TSH levels (normal TSH, ≤ 2.4; high-normal TSH, 2.5–4.4; and subclinical hypothyroid, ≥ 4.5 µIU/mL). Multiple linear regression analysis adjusted for cardiovascular risk factors was performed to determine the relationship between serum TSH level and renal function.

Results: The mean ± SD TSH level was 2.0 ± 1.4 µIU/mL, and 75.9% (n = 674) of the participants had normal, 17.9% (n = 159) had high-normal, and 6.2% (n = 55) had subclinical hypothyroid TSH levels. The mean eGFR significantly decreased with increased TSH levels (normal TSH, 79.3 ± 14.1; high-normal TSH, 77.4 ± 13.0; and subclinical hypothyroid, 72.3 ± 12.2 mL/min/1.73 m²: P for trend < 0.01). Multiple linear regression analysis extracted log-transformed TSH level as an independent factor correlated with eGFR in the high-normal TSH group (beta = −0.18, P = 0.02).

Conclusions: Our findings demonstrated a significant correlation between serum TSH levels and eGFR in high-normal TSH participants. In healthy individuals, high-normal TSH levels indicate increased the risk of chronic kidney disease.

Glycated albumin and its variability as an indicator of cardiovascular autonomic neuropathy development in type 2 diabetic patients

BACKGROUND

We investigated whether glycated albumin (GA) and its variability are associated with cardiovascular autonomic neuropathy (CAN) and further compared their associations with glycated hemoglobin (HbA1c).

METHODS

This retrospective longitudinal study included 498 type 2 diabetic patients without CAN. CAN was defined as at least two abnormal results in parasympathetic tests or presence of orthostatic hypotension. The mean, standard deviation (SD), and coefficient of variance (CV) were calculated from consecutively measured GA (median 7 times) and HbA1c levels (median 8 times) over 2 years. Logistic regression analysis was used to compare the associations between CAN and GA- or HbA1c-related parameters. Receiver operating characteristic (ROC) curve analysis was used to compare the predictive power for CAN between GA- and HbA1c-related parameters.

RESULTS

A total of 53 subjects (10.6%) developed CAN over 2 years. The mean, SD, and CV of GA or HbA1c were significantly higher in subjects with CAN. Higher mean GA and GA variability were associated with the risk of developing CAN, independent of conventional risk factors and HbA1c. In ROC curve analysis, the SD and CV of GA showed higher predictive value for CAN compared to the SD and CV of HbA1c, whereas the predictive value of mean GA did not differ from that of mean HbA1c. The mean, SD, and CV of GA showed additive predictive power to detect CAN development along with mean HbA1c.

CONCLUSIONS

Higher serum GA and its variability are significantly associated with the risk of developing CAN. Serum GA might be a useful indicator for diabetic complications and can enhance HbA1c's modest clinical prediction for CAN.

Do glycoalbumin levels preferentially reflect changes in postprandial glucose excursions?

AIMS

To evaluate whether plasma glycated albumin, which provides an integrated measure of plasma glucose levels over the preceding 2-4 weeks, better reflects changes in postprandial glucose excursions than HbA_1c .

METHODS

People with suboptimum glycaemic control on dual oral therapy were enrolled in the Treating-to-Target-in-Type 2 diabetes (4-T) trial, in which participants were randomized to the addition of once-daily basal insulin, twice-daily biphasic insulin or thrice-daily prandial insulin. Glycated albumin levels were assayed enzymatically from baseline and 1-year fasting plasma samples. We evaluated robust correlations of glycated albumin and HbA_1c both with fasting and postprandial glucose levels at these two time points, and with insulin-induced changes in the postprandial excursion.

RESULTS

Requisite data were available for 625 of the participants in the 4-T trial. Their mean (±sd) age was 62 ± 10 years and body weight was 85.8 ± 15.9 kg, and their median (interquartile range) diabetes duration was 9 (6, 13) years. Partial correlations at baseline and 1 year between postprandial glucose excursions and glycated albumin/HbA_1c , after adjusting for fasting glucose, were 0.27/0.15 and 0.22/0.18, respectively. Glycated albumin, compared with HbA_1c , explained 66% more of the variation in postprandial glucose excursions at baseline. At 1 year, postprandial glucose excursions on basal, biphasic and prandial and insulin therapy were reduced by 0.43, 0.78 and 1.88 mmol/l, respectively. These reductions were associated with changes in both glycated albumin and HbA_1c (P < 0.01), with a stronger association for glycated albumin.

CONCLUSION

Changes in glycated albumin and HbA_1c reflect changes in postprandial glucose excursions to a similar extent.

Higher dietary cholesterol and ω-3 fatty acid intakes are associated with a lower success rate of Helicobacter pylori eradication therapy in Japan

Background:Helicobacter pylori infection is a known risk factor for duodenal ulcers, gastritis, and gastric cancer. The eradication of H. pylori is successful in treating these disorders; however, the success rate of eradication therapy is declining. There may be an interaction with nutrient intake to account for this decline.Objective: We investigated the influence of food and nutrient intake on H. pylori eradication therapy.Design: In this study, 4014 subjects underwent endoscopy, were tested for serum antibodies to H. pylori (2046 positive; 51.0%), and had their food intake assessed with the use of a food-frequency questionnaire (FFQ). Of the positive subjects, endoscopies showed that 389 (19.0%) had gastritis and/or duodenal ulcers and were also positive for a ¹³C-urea breath test (UBT). These 389 subjects received 1-wk H. pylori eradication therapy with lansoprazole, amoxicillin, and clarithromycin and a second UBT 8 wk after treatment. Complete demographic characteristics, serum lipid, insulin, glycated hemoglobin, C-reactive protein (CRP), and creatinine concentrations as well as complete FFQs were available for 352 subjects. Multivariate logistic regression analyses were performed to determine factors that were associated with successful H. pylori eradication therapy.Results: The success rate of eradication therapy was 60.4% (235 of 389). Factors associated with the failure of eradication therapy included increased age (P = 0.02), higher CRP concentrations (P < 0.01), higher dietary cholesterol (P < 0.01) or egg intake (P < 0.01), higher ω-3 (n-3) fatty acid (P = 0.02) or fish intake (P = 0.01), and higher vitamin D intake (P = 0.02). Moreover, the higher vitamin D intake was strongly linked to higher fish intake. A limitation of the study is that we did not assess the antibiotic resistance of H. pyloriConclusions: Our results indicate that higher egg and fish intake may be negatively correlated with successful H. pylori eradication therapy in H. pylori-positive subjects with gastritis and/or duodenal ulcers.

Abundance matters: role of albumin in diabetes, a proteomics perspective

INTRODUCTION

Human serum albumin (HSA) is a multifaceted protein with vital physiological functions. It is the most abundant plasma protein with inherent capability to bind to diverse ligands, and thus susceptible to various post-translational modifications (PTMs) which alter its structure and functions. One such PTM is glycation, a non-enzymatic reaction between reducing sugar and protein leading to formation of heterogeneous advanced glycation end products (AGEs). Glycated albumin (GA) concentration increases significantly in diabetes and is implicated in development of secondary complications. Areas covered: In this review, we discuss in depth, formation of GA and its consequences, approaches used for characterization and quantification of GA, milestones in GA proteomics, clinical relevance of GA as a biomarker, significance of maintaining abundant levels of albumin and future perspectives. Expert commentary: Elevated GA levels are associated with development of insulin resistance as well as secondary complications, in healthy and diabetic individuals respectively. Mass spectrometry (MS) based approaches aid in precise characterization and quantification of GA including early and advanced glycated peptides, which can be useful in prediction of the disease status. Thus GA has evolved to be one of the best candidates in the pursuit of diagnostic markers for prediction of prediabetes and diabetic complications.

Metrics Beyond Hemoglobin A1C in Diabetes Management: Time in Range, Hypoglycemia, and Other Parameters

We review clinical instances in which A1C should not be used and reflect on the use of other glucose metrics that can be used, in substitution of or in combination with A1C and SMBG, to tailor an individualized approach that will result in better outcomes and patient empowerment.

Multicenter evaluation of an enzymatic method for glycated albumin

BACKGROUND

The use of glycated albumin (GA) has been proposed as an additional glycemic control marker particularly useful in intermediate-term monitoring and in situation when HbA_1c test is not reliable.

METHODS

We have performed the first multicenter evaluation of the analytical performance of the enzymatic method quantILab Glycated Albumin assay implemented on the most widely used clinical chemistry analyzers (i.e. Abbott Architect C8000, Beckman Coulter AU 480 and 680, Roche Cobas C6000, Siemens ADVIA 2400 and 2400 XPT).

RESULTS

The repeatability of the GA measurement (expressed as CV, %) implemented in the participating centers ranged between 0.9% and 1.2%. The within-laboratory CVs ranged between 1.2% and 1.6%. A good alignment between laboratories was found, with correlation coefficients from 0.996 to 0.998. Linearity was confirmed in the range from 7.6 to 84.7%.

CONCLUSION

The new enzymatic method for glycated albumin evaluated by our investigation is suitable for clinical use.

Glycated albumin: from biochemistry and laboratory medicine to clinical practice

This review summarizes current knowledge about glycated albumin. We review the changes induced by glycation on the properties of albumin, the pathological implications of high glycated albumin levels, glycated albumin quantification methods, and the use of glycated albumin as a complementary biomarker for diabetes mellitus diagnosis and monitoring and for dealing with long-term complications. The advantages and limits of this biomarker in different clinical settings are also discussed.

Cardiovascular disease prevalence and insulin resistance in the Kyushu-Okinawa Population Study and the Framingham Offspring Study

BACKGROUND

Age-adjusted cardiovascular disease (CVD) prevalence rates are significantly lower in Japan than in the United States.

OBJECTIVE

Our aim was to compare CVD risk in participants in Fukuoka and Framingham.

METHODS

We measured glucose, insulin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), small dense LDL-C, and triglycerides in men and women from Fukuoka (n = 1108), and age (median, 53 years) and gender-matched subjects from Framingham (n = 1101). Blood pressure, body mass index, use of medications, and history of CVD were also assessed.

RESULTS

CVD prevalence rates were more than 6-fold higher in Framingham men and women than their Fukuoka counterparts (P < .001). Median body mass index, LDL-C, insulin levels, and insulin resistance assessment in Fukuoka men and women were significantly (P < .01) lower than in Framingham; however, diabetes prevalence in Fukuoka men was significantly (P < .01) higher than in Framingham men, whereas female rates were similar, as were levels of systolic blood pressure. High-density lipoprotein cholesterol and surprisingly small dense LDL-C levels were significantly (P < .001) higher in Fukuoka than in Framingham. Standard risk factors do not account for the large differences in CVD prevalence rates between the 2 populations, and population differences in insulin resistance may explain some of these differences.

CONCLUSIONS

Our data are consistent with the concept that the CVD prevalence rate in a Japanese population is much lower than those observed in the United States, and that these differences cannot be explained by standard CVD risk factors, but may relate to marked population differences in insulin resistance.

Glycated albumin induces lipid infiltration in mice aorta independently of DM and RAS local modulation by inducing lipid peroxidation and inflammation

AIMS

Advanced glycated albumin (AGE-albumin) adversely impairs macrophage lipid homeostasis in vitro, which may be prevented by angiotensin receptor blockers. In vivo studies are inconclusive whether AGE-albumin itself plays important role in early-stage atherogenesis. We aimed at investigating how AGE-albumin by itself drives atherosclerosis development in dyslipidemic non-diabetic mice and if its effects are due to the activation of renin-angiotensin system in the arterial wall and the expression of genes and proteins involved in lipid flux.

METHODS AND RESULTS

Murine albumin glycation was induced by incubation with 10mM glycolaldehyde and C-albumin with PBS alone. Twelve-week-old-male apoE knockout mice were submitted to a daily IP injection of control (C) or AGE-albumin (2mg/mL) during 30days with or without losartan (LOS: 100mg/L; C+LOS and AGE+LOS). Aortic arch was removed, and gene expression was determined by RT-PCR and protein content by immunofluorescence. Plasma lipid and glucose levels were similar among groups. Systolic blood pressure was similarly reduced in both groups treated with LOS. In comparison to C-albumin, aortic lipid infiltration was 5.3 times increased by AGE-albumin, which was avoided by LOS. LOS prevented the enhancement induced by AGE-albumin in Ager, Tnf and Cybb mRNA levels but did not reduce Olr1. Nfkb and Agt mRNA levels were unchanged by AGE-albumin. LOS similarly reduced Agtr1a mRNA level in both C and AGE-albumin groups. In AGE-albumin-treated mice, immunofluorescence for carboxymethyl-lysine, 4-hydroxynonenal and RAGE was respectively, 4.8, 2.6 and 1.7 times enhanced in comparison to C-albumin. These increases were all avoided by LOS.

CONCLUSIONS

AGE-albumin evokes a pre-stage of atherogenesis in dyslipidemic mice independently of the presence of diabetes mellitus or modulation in the RAS in part by the induction of lipid peroxidation and inflammation.

The association of serum glycated albumin with the prevalence of diabetic retinopathy in Korean patients with type 2 diabetes mellitus

AIMS

To determine the clinical relationship between serum glycated albumin (GA) and diabetic retinopathy in Korean patients with type 2 diabetes mellitus (T2DM).

METHODS

A cross-sectional study including 424 patients with T2DM was conducted. Patients were divided into groups based on the presence of diabetic retinopathy and tertiles of serum GA and 1,5-anhydroglucitol levels.

RESULTS

Patients in the highest tertile of GA had a higher risk of diabetic retinopathy than those in the lowest tertile. Further analysis divided the groups based on glycated hemoglobin (HbA1c) levels, either above or below 8% (64mmol/mol), and revealed that in those with a HbA1c below 8% (64mmol/mol), the higher GA subgroup had an increased presence of diabetic retinopathy.

CONCLUSIONS

An increased GA level was significantly correlated with the presence of diabetic retinopathy, and measuring GA levels in addition to HbA1c was beneficial as a marker for retinopathy, especially in patients with moderate glycemic control.

Glycated Albumin is Independently Associated With Arterial Stiffness in Non-Diabetic Chronic Kidney Disease Patients

Glycated albumin (GA) exhibits atherogenic effects and increased serum GA levels are associated with the development of cardiovascular complications in diabetic patients. GA production also increases with aging, oxidative stress, and renal dysfunction. We performed this study to further ascertain the association between GA and arterial stiffness in nondiabetic chronic kidney disease (CKD) patients. We enrolled 129 nondiabetic CKD patients. Arterial stiffness was measured by brachial-ankle pulse wave velocity (baPWV) using a volume plethysmographic instrument along with simultaneous measurements of GA. Insulin resistance was determined with the homeostatic model assessment. The estimated glomerular filtration rate was calculated using serum creatinine and cystatin C according to the CKD-EPI Creatinine-Cystatin C equation adjusted for age, sex, and race (eGFRcr-cys). Nondiabetic CKD patients with arterial stiffness (baPWV ≥1400 cm/s) showed higher GA levels than those without arterial stiffness (14.2 [8.7-20.2]% vs 13.0 [8.8-18.9]%, P = 0.004). In the subgroup analysis, the patients who had both a higher GA level and a lower eGFRcr-cys, showed the highest baPWV compared with patients with a higher GA or a lower GFR alone. By Spearman's correlation analysis, GA correlated significantly with baPWV (r = +0.291, P = 0.001) and fasting serum glucose level (r = +0.191, P = 0.030), whereas The homeostatic model assessment of insulin resistance did not show any significant correlation with baPWV. Systolic blood pressure (r = +0.401 P < 0.001), age (r = +0.574, P < 0.001), high-density lipoprotein (HDL)-cholesterol level (r = -0.317, P < 0.001), and eGFRcr-cys (r = -0.285, P = 0.002) had a significant correlation with baPWV. According to multivariable logistic regression analysis, higher GA and systolic blood pressure were the independent risk factors affecting arterial stiffness. Our results suggest that serum GA is a potential risk factor of arterial stiffness in nondiabetic CKD patients.

The relation of postprandial plasma glucose and serum endostatin to the urinary albumin excretion of residents with prediabetes: results from the Kyushu and Okinawa Population Study (KOPS)

BACKGROUND

Previous clinical studies have shown that the circulating level of endostatin is related to kidney injury. We hypothesized that the impact of HbA1c, fasting, and postprandial plasma glucose on urinary albumin excretion would be related to the serum endostatin level.

METHODS

A cross-sectional, community-based population study of 1057 Japanese residents was conducted. Of these subjects, 162 with a fasting plasma glucose value between 5.5 and 6.9 mmol/L and an HbA1c level of <6.5 % received an oral glucose tolerance test, had serum endostatin measured, and had the urinary albumin/creatinine ratio (UACR) calculated.

RESULTS

In multivariate analysis, 2-h postprandial plasma glucose (β = 0.26, P < 0.01) was significantly associated with log-transformed UACR, independently of fasting plasma glucose (β = 0.14, P = 0.28) and HbA1c (β = -0.08, P = 0.57). When divided by the median value of endostatin (82.2 ng/mL), 2-h postprandial plasma glucose (β = 0.38, P = 0.01) remained significantly associated with the log-transformed UACR of the participants below the median, while the fasting plasma glucose (β = 0.34, P = 0.046) was independently associated with the log-transformed UACR of participants above the median.

CONCLUSION

Postprandial plasma glucose was independently associated with the urinary albumin excretion of the residents with prediabetes. Moreover, this relationship was limited to residents with a serum endostatin level below the median.

Association of IL28B rs8099917 genotype and female sex with spontaneous clearance of hepatitis C virus infection: a Japanese cross-sectional study

Hepatitis C virus (HCV) infection is a serious global health problem. Previous studies have suggested that the interleukin 28B (IL28B) rs8099917 genotype is related to spontaneous clearance of HCV in Caucasian populations. Our objective was to investigate the association of the IL28B rs8099917 genotype with spontaneous clearance of HCV by community-dwelling Japanese. A cross-sectional community-based population study of 993 Japanese residents was conducted. Based on anti-HCV antibody and HCV RNA levels, 50 subjects were assigned to the spontaneous-clearance group, 155 to the chronic-infection group, and 788 to the control group. Logistic regression analysis was done to examine the roles of the IL28B rs8099917 genotype and sex. To analyze the interactions between these factors, an "IL28B rs809991 genotype × sex" interaction term was included in the multivariate analysis. Significantly more subjects in the spontaneous-clearance group than in the chronic-infection group had the favorable IL28B rs8099917 genotype and were female. Multivariate logistic regression analysis extracted the favorable IL28B rs8099917 TT genotype (odds ratio [OR] 9.39; 95% confidence interval [CI], 2.16-40.83, P = 0.003) and female sex (OR, 2.27; 95% CI, 1.16-4.45, P = 0.017) as factors contributing to the spontaneous clearance of HCV. No significant interaction was found between the IL28B rs8099917 genotype and sex (P for interaction = 0.428). Both the favorable IL28B rs8099917 genotype and female sex were associated with the spontaneous clearance of HCV in this Japanese population.

GLYCATED ALBUMIN AT 4 WEEKS CORRELATES WITH A1C LEVELS AT 12 WEEKS AND REFLECTS SHORT-TERM GLUCOSE FLUCTUATIONS

OBJECTIVE

Evaluate the performance of glycated albumin (GA) monitoring by comparing it to other measures of glycemic control during intensification of antidiabetic therapy.

METHODS

This 12-week, prospective, multicenter study compared the diagnostic clinical performance of GA to glycated hemoglobin A1C (A1C), fructosamine corrected for albumin (FRA), fasting plasma glucose (FPG), and mean blood glucose (MBG) estimated from self-monitoring of blood glucose (SMBG) and continuous glucose monitoring (CGM) in 30 patients with suboptimally controlled type 1 or 2 diabetes.

RESULTS

Mean A1C decreased from 9.5% to 8.1%. Mean SMBG correlated closely with CGM (Pearson r = 0.783 for daily estimates and r = 0.746 for weekly estimates, P<.0001). Both GA and FRA levels significantly correlated with changes from baseline in A1C and mean weekly SMBG (P<.001). The lowest observed median GA occurred at 4 weeks, followed by a small increase and then a slight reduction, mirroring changes in overall mean SMBG values. The median A1C fell throughout the treatment period, failing to reflect short-term changes in SMBG. A ≥1% reduction in GA at 4 weeks was significantly associated with a ≥0.5% change in A1C at 12 weeks (odds ratio [OR] = 19.0, 95% confidence interval [CI]: 1.4, 944, P = .018).

CONCLUSION

In patients receiving glucose-lowering therapy, changes in GA at 4 weeks were concordant with changes in A1C at 12 weeks, and both GA and FRA more accurately reflected short-term blood glucose fluctuations than A1C.

The association between objective tongue color and endoscopic findings: results from the Kyushu and Okinawa population study (KOPS)

Background

The relation between tongue color and gastroesophageal disease is unclear. This study was done to investigate the associations between tongue color (TC), endoscopic findings, Helicobacter.pylori infection status, and serological atrophic gastritis (SAG).

Methods

The participants were 896 residents of Ishigaki Island, Okinawa, aged 28–86 years. The tongue was photographed, esophagogastroduodenoscopy was done, and serum antibody to H.pylori was measured. SAG was defined as a serum Pepsinogen (PG)Ilevel ≤70 ng/ml and a PGI/IIratio ≤3.0. TC was measured by the device-independent international commission on Illumination 1976 L*a*b* color space standards at four points: (1) edge, (2) posterior, (3) middle, and (4) apex. We also calculated the ratio of the tongue edge to the three other measured points to examine the association between the coating of the tongue and the endoscopic and laboratory findings.

Results

Participants were excluded who had two or more endoscopic findings (n = 315) or who had SAG without seropositivity to H.pylori (n = 33). The remaining 548 participants were divided into three groups: SAG and seropositive to H.pylori (n = 67), seropositive to H.pylori alone (n = 56), and without SAG and seronegative for H.pylori (n = 425). We divided 425 residents into a single endoscopic finding positive group (n = 207) and a negative group, which served as a control (n = 218). The most frequent single endoscopic finding was esophageal hernia (n = 110), followed by erosive esophagitis (n = 35) and erosive gastritis (EG) (n = 45). EH was significantly associated with TC (2b*/1b*) (P < 0.05). EG was significantly associated with TC (3a*, 3b*) (P < 0.05). Seropositivity to H.pylori was significantly associated with TC (3 L*, 3 L*/1 L*) (P < 0.05, <0.01), and seropositivity to both H.pylori and SAG was significantly associated with TC (3 L*/1 L*) (P < 0.05). Multivariate analysis extracted TC (3a*, 3b*) as an independent factor associated with a differential diagnosis of EG (Odds ratio (OR) 2.66 P = 0.008, OR 2.17 P = 0.045).

Conclusions

The tongue body color of the middle area reflects acute change of gastric mucosa, such as erosive gastritis. Tongue diagnosis would be a useful, non-invasive screening tool for EG.

Oxidized LDL and Fructosamine Associated with Severity of Coronary Artery Atherosclerosis in Insulin Resistant Pigs Fed a High Fat/High NaCl Diet

Background

Insulin-resistant subjects develop more severe and diffuse coronary artery atherosclerosis than insulin-sensitive controls but the mechanisms that mediate this atherosclerosis phenotype are unknown.

Research Objective

To determine the metabolic parameters that associate with the severity of coronary atherosclerosis in insulin resistant pigs fed a high fat/high NaCl diet.

Key Methods

The primary endpoint was severity of coronary atherosclerosis in adult pigs (Sus scrofa, n = 37) fed a high fat diet that also contained high NaCl (56% above recommended levels) for 1 year.

Principal Findings

Twenty pigs developed severe and diffuse distal coronary artery atherosclerosis (i.e., severe = intimal area as a percent medial area > 200% in at least 2 coronary artery cross sections and diffuse distal = intimal area as a percent medial area ≥ 150% over 3 sections separated by 2 cm in the distal half of the coronary artery). The other 17 pigs had substantially less coronary artery atherosclerosis. All 37 pigs had blood pressure in a range that would be considered hypertensive in humans and developed elevations in total and LDL and HDL cholesterol, weight gain, increased backfat, and increased insulin resistance (Bergman Si) without overt diabetes. Insulin resistance was not associated with atherosclerosis severity. Five additional pigs fed regular pig chow also developed increased insulin resistance but essentially no change in the other variables and little to no detectible coronary atherosclerosis. Most importantly, the 20 high fat/high NaCl diet -fed pigs with severe and diffuse distal coronary artery atherosclerosis had substantially greater increases (p< 0.05) in oxidized LDL (oxLDL) and fructosamine consistent with increased protein glycation.

Conclusion

In pigs fed a high fat/high NaCl diet, glycated proteins are induced in the absence of overt diabetes and this degree of increase is associated with the development of severe and diffuse distal coronary artery atherosclerosis.

Association of hemoglobin A1c and glycated albumin with carotid atherosclerosis in community-dwelling Japanese subjects: the Hisayama Study

Background

It is not clear which glucose measure is more useful in the assessment of atherosclerosis. We investigated the associations of hemoglobin A_1c (HbA_1c), glycated albumin (GA), 1,5-anhydroglucitol (1,5-AG), fasting plasma glucose (FPG), and 2-hour postload glucose (PG) with carotid intima-media thickness (IMT) in community-dwelling Japanese subjects.

Methods

A total of 2702 subjects aged 40–79 years underwent a 75-g oral glucose tolerance test and measurements of HbA_1c, GA, 1,5-AG, and carotid IMT by ultrasonography in 2007–2008. Carotid wall thickening was defined as a maximum IMT of >1.0 mm. The crude and multivariable-adjusted linear and logistic regression models were used to analyze cross-sectional associations between levels of glycemic measures and carotid IMT.

Results

The crude average of the maximum IMT increased significantly with rising quartiles of HbA_1c, GA, FPG, and 2-hour PG levels in subjects with and without glucose intolerance (GI), while no clear association was observed for 1,5-AG. After adjustment for other confounding factors, positive trends for HbA_1c, GA, and FPG (all p for trend < 0.05), but not 2-hour PG (p = 0.07) remained robust in subjects with GI, but no such associations were found in those without GI. When estimating multivariable-adjusted β values for the associations of 1 SD change in glycemic measures with the maximum IMT in subjects with GI, the magnitude of the influence of HbA_1c (β = 0.021), GA (β = 0.024), and FPG (β = 0.024) was larger than that of 2-hour PG (β = 0.014) and 1,5-AG (β = 0.003). The multivariable-adjusted odds ratios for the presence of carotid wall thickening increased significantly with elevating HbA_1c, GA, and FPG levels only in subjects with GI (all p for trend < 0.001). Among subjects with GI, the area under the receiver operating characteristic curve significantly increased by adding HbA_1c (p = 0.04) or GA (p = 0.04), but not 1,5-AG, FPG, or 2-hour PG, to the model including other cardiovascular risk factors.

Conclusions

In community-dwelling Japanese subjects with GI, elevated HbA_1c, GA, and FPG levels were significantly associated with increased carotid IMT, and HbA_1c and GA provided superior discrimination for carotid wall thickening compared to 1,5-AG, FPG, and 2-hour PG, suggesting that HbA_1c and GA are useful for assessing carotid atherosclerosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-015-0247-7) contains supplementary material, which is available to authorized users.

Glycated albumin as a diagnostic tool for diabetes in a general Japanese population

OBJECTIVE

Diabetes mellitus is a major cause of cardiovascular, kidney, neurologic, and eye diseases, and may be preventable in some cases by lifestyle modification. Screening tests for diabetes mellitus include fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c). Our objective was to evaluate the utility of plasma glycated albumin (GA) in the diagnosis of diabetes mellitus.

DESIGN AND METHODS

A cross-sectional, community-based population study of 908 non-diabetic Japanese residents was conducted. Of these subjects, 176 with FPG value between 5.5 and 6.9mmol/l, and an HbA1c level of <6.5% received an oral glucose tolerance test (OGTT).

RESULTS

The OGTT results were used for the diagnosis of diabetes mellitus using World Health Organization criteria. Receiver operating characteristic (ROC) analyses demonstrated that optimal threshold values for the diagnosis of diabetes in this population were 15.2% for GA and 5.9% for HbA1c, respectively. Using these cutoff levels, the sensitivity of GA at 62.1% for detecting diabetes was the same as that of HbA1c. However the specificity for GA for detecting diabetes was 61.9%, while for HbA1c it was higher at 66.7%.

CONCLUSIONS

Our results indicate that the measurement of glycated albumin may serve as a useful screening test for diabetes in a general Japanese population.

1,5-anhydroglucitol is associated with early-phase insulin secretion in chinese patients with newly diagnosed type 2 diabetes mellitus

BACKGROUND

The goal of the present study was to explore the correlations of 1,5-anhydroglucitol (l,5-AG), glycated hemoglobin (HbA1c), and glycated albumin (GA) with insulin sensitivity and secretion.

SUBJECTS AND METHODS

In total, 302 patients with newly diagnosed type 2 diabetes mellitus (166 men, 136 women) were enrolled in this study. The homeostasis model assessment for insulin resistance (HOMA-IR) and homeostasis model assessment for β-cell function (HOMA-β) were calculated to determine the basal insulin sensitivity and secretion. The insulinogenic index (IGI) was used to evaluate early-phase insulin secretion. 1,5-AG and GA were assayed via the enzymatic method, and HbA1c was detected by high-pressure liquid chromatography.

RESULTS

Among all 302 subjects, the serum 1,5-AG level was 13.1±7.2 μg/mL, and the HbA1c and GA levels [median (interquartile range)] were 6.7% (6.2-7.3%) and 17.7% (16.0-19.5%), respectively. Increased 1,5-AG quartiles were accompanied by trends toward a decreased HOMA-IR and an increased HOMA-β and IGI (for all trends, P<0.001). 1,5-AG was negatively associated with HOMA-IR (r=-0.200, P<0.001) and positively associated with HOMA-β and IGI (r=0.210 and 0.413, respectively; both P<0.001). 1,5-AG was independently related to HOMA-IR and HOMA-β and exhibited an independent positive association with IGI (standardized β=0.242, P<0.001). Additionally, both HbA1c and GA were independently correlated with HOMA-IR and HOMA-β.

CONCLUSIONS

1,5-AG is not only correlated with basal insulin sensitivity and secretion, but also closely associated with early-phase insulin secretion in Chinese patients with newly diagnosed type 2 diabetes mellitus.

Recent topics in chemical and clinical research on glycated albumin

The measuring method for glycated albumin (GA) has been developed as a new glycemic control marker since the beginning of the 21st century. Since GA has an advantage in reflecting glycemic status over a shorter period than hemoglobin A1c (HbA1c), much research and many reviews have been reported. However, so far there have been few reports on glycation sites based on the tertiary structure of human serum albumin (HSA) and the comparison of glycation rates between GA and HbA1c in detail. The present review discusses how the glycation sites of lysine residues in HSA are modified with glucose, whereas the glycation sites of lysine residues are located inside of HSA as well as the direct comparison of glycation rates between GA and HbA1c using human blood. Moreover, the most recent clinical researches on GA are described.

Glycated albumin is more closely correlated with coronary artery disease than 1,5-anhydroglucitol and glycated hemoglobin A1c

BACKGROUND

The aim of this study was to investigate the associations of two nontraditional glycemic markers, glycated albumin (GA) and 1,5-anhydroglucitol (1,5-AG), as well as glycated hemoglobin A1c (HbA1c) with coronary artery disease (CAD).

METHODS

In total, 272 subjects (178 men and 94 postmenopausal women) were enrolled in this study. All of them underwent coronary angiography which was used to diagnose CAD. The severity of coronary artery stenosis was assessed by the coronary stenosis index (CSI). GA and 1,5-AG were assayed using the enzymatic method, and HbA1c was detected by high-pressure liquid chromatography.

RESULTS

The HbA1c and GA levels were significantly higher in CAD group than those in non-CAD group (both P < 0.01). While the 1,5-AG level was significantly lower in CAD group than that in non-CAD group (P < 0.05). After adjustment for traditional risk factors of CAD, HbA1c, 1,5-AG, and GA, multivariate logistic regression analysis showed that GA was an independent risk factor for CAD (odds ratio = 1.143, 95% confidence interval: 1.048-1.247, P = 0.002). With CSI as a dependent variable, multiple stepwise regression analysis demonstrated an independent positive correlation between GA and CSI (standardized β = 0.184, P = 0.003), beyond gender, age, and lipid-lowering therapy, after adjustment for traditional risk factors of CAD, HbA1c, 1,5-AG, and GA.

CONCLUSIONS

GA was more closely correlated with CAD than HbA1c and 1,5-AG in a Chinese population with high risk of CAD.

Subclinical carotid atherosclerosis and triglycerides predict the incidence of chronic kidney disease in the Japanese general population: results from the Kyushu and Okinawa Population Study (KOPS)

OBJECTIVE

To examine whether or not subclinical atherosclerosis independently predicts the incidence of chronic kidney disease (CKD) in the Japanese general population.

METHODS

This study is part of the Kyushu and Okinawa Population Study (KOPS), a survey of vascular events associated with lifestyle-related diseases. Participants who attended both baseline (2004-2007) and follow-up (2009-2012) examinations were eligible. The common carotid intima-media thickness (IMT) was assessed for each participant at baseline. The end point was the incidence of CKD, defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2) during the follow-up of participants without CKD at baseline.

RESULTS

During the five-year follow-up, 224 of the 1824 participants (12.3%) who developed CKD had higher carotid IMT (0.74 ± 0.22 vs. 0.65 ± 0.14 mm, P < 0.001), higher triglycerides (1.6 ± 0.8 vs. 1.3 ± 0.7 mmol/L, P < 0.001), and lower high density lipoprotein cholesterol (1.5 ± 0.4 vs. 1.6 ± 0.4 mmol/L, P < 0.001) at baseline than those who did not. In logistic regression analysis adjusted for significant covariates, eGFR (Odds ratio [OR] 0.83, 95% confidence interval (CI) 0.80-0.85, P < 0.001), carotid IMT (0.10 mm increase: OR 1.17, 95% CI 1.04-1.33, P = 0.010), and triglycerides (OR 1.35, 95% CI 1.06-1.73, P = 0.015) at baseline were independent predictors for the development of CKD.

CONCLUSIONS

Higher carotid IMT and hypertriglyceridemia were independently associated with the development of CKD in the population studied.

1,5-Anhydroglucitol and glycated albumin in glycemia

The main purpose of treating diabetes is to prevent the onset and the progression of diabetic chronic complications. Since the mechanism of onset of chronic complications is still not well understood, the main strategy to achieve this purpose is to bring the plasma glucose level in diabetic patients as close as possible to that in healthy subjects and try to maintain good glycemic control over the long term. Glycated hemoglobin (HbA1c), glycated albumin (GA), fructosamine, and 1,5-anhydroglucitol (1,5 AG) are used for evaluating glycemic control. At present, HbA1c is widely used as a gold standard index for glycemic control in clinical practice. While HbA1c reflects the long-term glycemic control state (for the past 1-2 months), it does not accurately reflect glycemic control in the clinical state in which glycemic control improves or deteriorates in the short-term. It is also known that HbA1c in patients with hematological disorders such as anemia and variant hemoglobin shows an abnormal value. In addition, HbA1c mainly reflects the mean plasma glucose but does not reflect the postprandial plasma glucose. On the other hand, GA and 1,5-AG reflect intermediate- or short-term glycemic control and are not influenced by hemoglobin metabolism. While 1,5-AG is known to reflect the postprandial plasma glucose, it was shown recently that GA also reflects the postprandial plasma glucose. This chapter summarizes the measurement methods, usage methods, evidence, and problems concerning such indices for glycemic control.

Beyond HbA1c and glucose: the role of nontraditional glycemic markers in diabetes diagnosis, prognosis, and management

Fasting glucose and hemoglobin A1c (HbA1c) are the standard measures for diagnosis and monitoring of diabetes. There has been recent interest in nontraditional markers of hyperglycemia, including fructosamine, glycated albumin, and 1,5-anhydroglucitol (1,5-AG), as alternatives or adjuncts to standard measures. There is a growing literature linking these nontraditional markers with microvascular and macrovascular complications. Fructosamine and glycated albumin have also been shown to improve identification of persons with diabetes. However, long-term prospective studies with clinical outcomes are lacking. Some modern laboratory assays for fructosamine, glycated albumin, and 1,5-AG have excellent performance. Expanded use of these tests has the potential to improve diabetes care as these measures may overcome limitations of HbA1c in certain patients, complement traditional measures by providing additional information on shorter-term glycemic control, and improve risk stratification for diabetes and its complications. Nonetheless, studies are needed to demonstrate if their routine use will benefit patients and improve outcomes.

The utility of urinary myo-inositol as a marker of glucose intolerance

OBJECTIVE

The most common screening tests for glucose intolerance are fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c). Because it reflects the current status of hyperglycemia, urinary myo-inositol (UMI) may be useful. We evaluated UMI as a screening tool for glucose intolerance.

DESIGN AND METHODS

A cross-sectional, community-based population study of 1057 Japanese residents. 173 with an FPG level between 5.5 and 6.9 mmol/L and an HbA1c under 6.5% had an oral glucose tolerance test. We measured UMI level before (fasting UMI) and 2h after (2h-UMI) glucose ingestion. Δ-UMI was defined as the difference between fasting UMI and 2h-UMI.

RESULTS

Δ-UMI, 2h-UMI and HbA1c levels significantly increased as glucose intolerance worsened. Δ-UMI level was significantly positively correlated with 2h-UMI level (r=0.896, p<0.001). Using cutoff levels from receiver operating characteristic (ROC) analyses, the sensitivity of Δ-UMI (82.1%) and 2h-UMI (79.3%) were higher than that of HbA1c (48.3%). The area under the ROC curve values for Δ-UMI (0.903) and 2h-UMI (0.891) were higher than that for HbA1c (0.785).

CONCLUSIONS

2h-UMI is useful as a non-invasive screening of glucose intolerance.

Relationship of glycated albumin to blood glucose and HbA1c values and to retinopathy, nephropathy, and cardiovascular outcomes in the DCCT/EDIC study

The association of chronic glycemia, measured by HbA(1c), with long-term complications of type 1 diabetes has been well established in the Diabetes Control and Complications Trial (DCCT) and other studies. The role of intermediate-term and acute glycemia and of glucose variability on microvascular and cardiovascular disease (CVD) is less clear. In order to examine the interrelationships among long-term, intermediate-term, and acute measures of glucose and its daily variability, we compared HbA(1c), glycated albumin (GA), and seven-point glucose profile concentrations measured longitudinally in a case-cohort subpopulation of the DCCT. HbA(1c) and GA were closely correlated with each other and with the mean blood glucose (MBG) calculated from the seven-point profile. The associations of glucose variability and postprandial concentrations with HbA(1c) and GA were relatively weak and were further attenuated when MBG was included in multivariate models. In the case-cohort analyses, HbA(1c) and GA had similar associations with retinopathy and nephropathy, which were strengthened when both measures were considered together. Only HbA(1c) was significantly associated with CVD. The demonstrated interrelationships among different measures of glycemia will need to be considered in future analyses of their roles in the development of long-term complications of type 1 diabetes.

Association of increased serum glycated albumin levels with low coronary collateralization in type 2 diabetic patients with stable angina and chronic total occlusion

BACKGROUND

We investigated whether serum glycated albumin (GA) levels are related to coronary collateralization in type 2 diabetic patients with chronic total occlusion.

METHODS

Blood levels of GA and glycosylated hemoglobin (HbA1c) were determined in 317 diabetic and 117 non-diabetic patients with stable angina and angiographic total occlusion of at least one major coronary artery. The degree of collaterals supplying the distal aspect of a total occlusion from the contra-lateral vessel was graded as low (Rentrop score of 0 or 1) or high collateralization (Rentrop score of 2 or 3).

RESULTS

For diabetic patients, GA (21.2 ± 6.5% vs. 18.7 ± 5.6%, P < 0.001) but not HbA1c levels (7.0 ± 1.1% vs. 6.8 ± 1.3%, P = 0.27) was significantly elevated in low collateralization than in high collateralization group, and correlated inversely with Rentrop score (Spearmen's r = -0.28, P < 0.001; Spearmen's r = -0.10, P = 0.09, respectively). There was a trend towards a larger area under the curve of GA compared with that of HbA1c for detecting the presence of low collateralization (0.64 vs. 0.58, P = 0.15). In non-diabetic patients, both GA and HbA1c levels did not significantly differ regardless the status of coronary collateralization. In multivariable analysis, female gender, age > 65 years, smoke, non-hypertension, duration of diabetes > 10 years, metabolic syndrome, eGFR < 90 ml/min/1.73 m2, and GA > 18.3% were independently determinants for low collateralization in diabetic patients.

CONCLUSIONS

Increased GA levels in serum are associated with impaired collateral growth in type 2 diabetic patients with stable angina and chronic total occlusion.

Serum cholesterol and triglyceride reference ranges of twenty lipoprotein subclasses for healthy Japanese men and women

AIM

This epidemiological study was done to generate normal ranges for the cholesterol and triglyceride levels in serum lipoprotein subclasses isolated from healthy adults based on gender and menopausal status.

METHODS

Cholesterol and triglyceride levels in 20 lipoprotein subclasses as separated by high performance liquid chromatography were measured in serum obtained from 825 fasting healthy subjects (267 men, 558 women).

RESULTS

For serum cholesterol, 13.7% was found in very low density lipoprotein (VLDL) subclasses, 55.6% in low density lipoprotein (LDL) subclasses, and 30.4% in high density lipoprotein (HDL) subclasses. For serum triglycerides, these values were 52.1%, 27.9%, and 17.4%, respectively. Levels of cholesterol in some VLDL subclasses were inversely correlated with the levels of some HDL subclasses, while for triglycerides, elevated levels in any one subclass were generally strongly associated with elevated levels in all other subclasses. Men had significantly higher large VLDL-cholesterol levels than women (P < 0.05), while women had significantly higher small VLDL-cholesterol levels than men (P < 0.001). Women had significantly higher large LDL- and large and medium HDL-cholesterol levels than men (P < 0.001). Men had significantly higher chylomicron (CM), large and medium VLDL-, and small LDL-triglyceride levels than women (P < 0.001). Women had significantly higher very large and large HDL-triglyceride levels than men (P < 0.01). Postmenopausal women had significantly higher CM, all VLDL, and large, medium and small LDL-cholesterol levels, and significantly higher all VLDL, LDL, and HDL-triglyceride levels than premenopausal women (P < 0.001).

CONCLUSIONS

Our data document important gender and menopausal status differences in cholesterol and triglyceride subclass levels, as well as significant correlations between values in the various serum lipoprotein subclasses.

The serum undercarboxylated osteocalcin level and the diet of a Japanese population: results from the Kyushu and Okinawa Population Study (KOPS)

The elevated serum undercarboxylated osteocalcin (ucOC) level is related to osteoporosis. In Japan, vitamin K intake is lower, and the incidence of hip fractures noticeably higher in northern Kyushu than in other areas. The study was done to determine the serum ucOC levels in a Japanese population and its association with diet and glucose metabolism. The data of 3,658 healthy adults aged 40-69 (1,373 men and 2,285 women) who lived in northern Kyushu area were analyzed. The data included anthropometric measurements and a self-reported personal interview on daily intake of foods. The serum ucOC level of each participant was measured by electrochemiluminescence immunoassay. Glycohemoglobin A1c (HbA1c), fasting plasma glucose, and serum insulin concentrations were measured. The median serum ucOC level of the women (4.65 ng/mL) was significantly higher than that of the men (3.04 ng/mL) (P = 0.0021). The age-specific ucOC levels of the men decreased significantly with age. In contrast, the ucOC levels of the women aged ≥50 were elevated, but the levels varied markedly within the other age groups. For both men and women, multivariate analysis identified a daily diet rich in vitamin K and HbA1c level as independently having a significant, negative relationship to serum ucOC level. Our study indicates that the serum ucOC decreases with age in men, increases postmenopausally in women, and correlates inversely with dietary consumption of certain foods and with fasting glucose and HbA1c level.