Clinical usefulness of serum 1,5-anhydroglucitol in monitoring glycaemic control

Measurement of serum 1,5-AG provides insights for diabetes management and the anti-viral immune response

BACKGROUND

Achieving an in-range glycated haemoglobin (HbA1c) is essential for managing diabetes mellitus (DM). However, this parameter provides an estimate of long-term blood glucose control rather than daily glycaemic variations. Glycaemic variability can be more predictive than HbA1c in terms of identifying those at risk for diabetes complications, including risk of severe respiratory virus infections and is usually measured via a continuous glucose monitor (CGM). For individuals for whom a CGM is not available, serum 1,5 anhydroglucitol (1,5-AG) level has shown potential as an alternative method for monitoring glycaemic variability. Despite this, at present 1,5-AG is not routinely used in the clinical assessment of DM. Here, we aim to determine whether assessing 1,5-AG, in addition to HbA1c, is of any potential clinical utility to the management of DM for patients.

METHODS

Using machine learning and data derived from 78 patients with type I DM (for whom CGM data is available) we show that the combination of 1,5-AG and HbA1c improves the prediction of a patient's glycemia risk index (GRI) compared to HbA1c alone.

RESULTS

The GRI is an essential tool in the management of DM as it reflects both clinical priorities and patient centred outcomes. The inclusion of 1,5-AG in this prediction was particularly important for individuals who had very high or very low GRI. Furthermore, in the context of glycaemic variability and susceptibility to severe respiratory virus infections, we show that reduced 1,5-AG in the plasma is associated with reduced ex vivo CD4 + T cell cytokine responses to influenza virus in individuals with a matched HbA1c.

CONCLUSIONS

Taken together, these data argue for an increased monitoring of 1,5-AG in the clinic for individuals without a CGM to provide additional insights for diabetes management.

Serum betaine and dimethylglycine in mid-pregnancy and the risk of gestational diabetes mellitus: a case-control study

PURPOSE

To investigate the associations of choline, betaine, dimethylglycine (DMG), L-carnitine, and Trimethylamine-N-oxide (TMAO) with the risk of Gestational diabetes mellitus (GDM) as well as the markers of glucose homeostasis.

METHODS

We performed a case-control study including 200 diagnosed GDM cases and 200 controls matched by maternal age (±2 years) and gestational age (±2 weeks). Concentrations of serum metabolites were measured by the high-performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS).

RESULTS

Compared to the control group, GDM group had significantly lower serum betaine concentration and betaine/choline ratio, and higher DMG concentration. Furthermore, decreased betaine concentration and betaine/choline ratio, increased DMG concentration showed significant association with the risk of GDM. In addition, serum betaine concentrations were negatively associated with blood glucose levels at 1-h post-glucose load (OGTT-1h), and both betaine and L-carnitine concentrations were positively associated with 1,5-anhydroglucitol levels. Betaine/choline ratio was negatively associated with OGTT-1h and blood glucose levels at 2-h post-glucose load (OGTT-2h) and serum choline concentrations were negatively associated with fasting blood glucose and positively associated with OGTT-2h.

CONCLUSION

Decreased serum betaine concentrations and betaine/choline ratio, and elevated DMG concentrations could be significant risk factors for GDM. Furthermore, betaine may be associated with blood glucose regulation and short-term glycemic fluctuations.

Markers for obese and non-obese Type 2 diabetes identified using whole blood metabolomics

Definitive differences in blood metabolite profiles between obese and non-obese Type 2 diabetes (T2D) have not been established. We performed an LC-MS-based non-targeted metabolomic analysis of whole blood samples collected from subjects classified into 4 types, based on the presence or absence of obesity and T2D. Of the 125 compounds identified, 20, comprising mainly nucleobases and glucose metabolites, showed significant increases or decreases in the T2D group. These included cytidine, UDP-glucuronate, UMP, 6-phosphogluconate, and pentose-phosphate. Among those 20 compounds, 11 enriched in red blood cells (RBCs) have rarely been studied in the context of diabetes, indicating that RBC metabolism is more extensively disrupted than previously known. Correlation analysis revealed that these T2D markers include 15 HbA1c-associated and 5 irrelevant compounds that may reflect diabetic conditions by a different mechanism than that of HbA1c. In the obese group, enhanced protein and fatty acid catabolism causes increases in 13 compounds, including methylated or acetylated amino acids and short-chain carnitines. Our study, which may be considered a pilot investigation, suggests that changes in blood metabolism due to obesity and diabetes are large, but essentially independent.

Prognostic value of 1,5-anhydro-D-glucitol incorporating syntax score in acute coronary syndrome

The utility of adding information on 1,5-anhydro-D-glucitol (1,5-AG), a marker for postprandial hyperglycemia, to a pre-existing scoring system in acute coronary syndrome (ACS) patients is unknown. This retrospective cohort study included 266 ACS patients. The end point was major adverse cardiac and cerebral events (MACCE) through 5 years of follow-up. To evaluate incremental benefits of combining 1,5-AG with the syntax score, we applied time-dependent receiver operating curve (ROC) analysis, net reclassification improvement (NRI), integrated discrimination improvement (IDI) and decision curve analysis (DCA). Temporal changes to the area under time-dependent ROC curves showed that addition of 1,5-AG parameters to syntax score did not provide any incremental value (area under the curve for syntax alone, 0.673 (95% confidence interval (CI), 0.599-0.747) vs. with 1,5-AG combined, 0.671 (95%CI 0.596-0.746; Delong p = 0.65). Incorporating 1,5-AG into syntax score yielded a significant NRI of 0.291 (95%CI 0.015-0.567) and IDI of 0.055 (95%CI 0.018-0.093), while DCA analysis showed the limited net benefit in combination with 1,5-AG and syntax score. 1,5-AG values exhibited significant discriminatory utility for detecting MACCE within the ACS population. However, 1,5-AG levels contributed limited utility beyond syntax score based on time-dependent ROC and DCA analyses.Trial registration: UMIN000023837.

Plasma metabolomic signatures of obesity and risk of type 2 diabetes

OBJECTIVE

The mechanisms linking obesity to type 2 diabetes (T2D) are not fully understood. This study aimed to identify obesity-related metabolomic signatures (MESs) and evaluated their relationships with incident T2D.

METHODS

In a nested case-control study of 2076 Chinese adults, 140 plasma metabolites were measured at baseline, linear regression was applied with the least absolute shrinkage and selection operator to identify MESs for BMI and waist circumference (WC), and conditional logistic regression was applied to examine their associations with T2D risk.

RESULTS

A total of 32 metabolites associated with BMI or WC were identified and validated, among which 14 showed positive associations and 3 showed inverse associations with T2D; 8 and 18 metabolites were selected to build MESs for BMI and WC, respectively. Both MESs showed strong linear associations with T2D: odds ratio (95% CI) comparing extreme quartiles was 4.26 (2.00-9.06) for BMI MES and 9.60 (4.22-21.88) for WC MES (both p-trend < 0.001). The MES-T2D associations were particularly evident among individuals with normal WC: odds ratio (95% CI) reached 6.41 (4.11-9.98) for BMI MES and 10.38 (6.36-16.94) for WC MES. Adding MESs to traditional risk factors and plasma glucose improved C statistics from 0.79 to 0.83 (p < 0.001).

CONCLUSIONS

Multiple obesity-related metabolites and MESs strongly associated with T2D in Chinese adults were identified.

1,5-Anhydroglucitol Predicts Mortality in Patients with HBV-Related Acute-on-chronic Liver Failure

BACKGROUND AND AIMS

1,5-Anhydroglucitol (1,5AG) activity has been reported in chronic liver disease. Hepatitis B virus (HBV)-related acute-on-chronic liver failure (HBV-ACLF) patients have a high mortality. We aimed to discover the relationship between serum 1,5AG and the prognosis of HBV-ACLF.

METHODS

Serum 1,5AG levels were determined in 333 patients with HBV-ACLF, 300 without diabetes were allocated to derivation (n=206) and validation cohorts (n=94), and 33 were recruited to evaluate 1,5AG in those with diabetes. Forty patients with chronic hepatitis B, 40 with liver cirrhosis, and 40 healthy people were controls in the validation cohort.

RESULTS

In the derivation and validation cohorts, serum 1,5AG levels were significantly lower in nonsurvivors than in survivors. The AUC of 1,5AG for 28-day mortality was 0.811. In patients with diabetes, serum 1,5AG levels were also significantly lower in nonsurvivors than in survivors. In multivariate Cox regression analysis, serum 1,5AG levels were independently associated with 28-day mortality. A novel predictive model (ACTIG) based on 1,5AG, age, TB, cholesterol, and INR was derived to predict mortality. In ACTIG, the AUC for 28-day mortality was 0.914, which was superior to some prognostic score models. ACTIG was also comparable to those prognostic score models in predicting 6-month mortality. In mice with D-galactosamine/lipopolysaccharide-induced liver failure, 1,5AG levels were significantly reduced in serum and significantly increased in urine and liver tissue.

CONCLUSIONS

Serum 1,5AG levels are a promising predictor of short-term mortality in HBV-ACLF patients. The 1,5AG distribution changed in mice with D-galactosamine/ lipopolysaccharide-induced liver failure.

Predictive Metabolomic Markers in Early to Mid-pregnancy for Gestational Diabetes Mellitus: A Prospective Test and Validation Study

Gestational diabetes mellitus (GDM) predisposes pregnant individuals to perinatal complications and long-term diabetes and cardiovascular diseases. We developed and validated metabolomic markers for GDM in a prospective test-validation study. In a case-control sample within the PETALS cohort (GDM n = 91 and non-GDM n = 180; discovery set), a random PETALS subsample (GDM n = 42 and non-GDM n = 372; validation set 1), and a case-control sample within the GLOW trial (GDM n = 35 and non-GDM n = 70; validation set 2), fasting serum untargeted metabolomics were measured by gas chromatography/time-of-flight mass spectrometry. Multivariate enrichment analysis examined associations between metabolites and GDM. Ten-fold cross-validated LASSO regression identified predictive metabolomic markers at gestational weeks (GW) 10-13 and 16-19 for GDM. Purinone metabolites at GW 10-13 and 16-19 and amino acids, amino alcohols, hexoses, indoles, and pyrimidine metabolites at GW 16-19 were positively associated with GDM risk (false discovery rate <0.05). A 17-metabolite panel at GW 10-13 outperformed the model using conventional risk factors, including fasting glycemia (area under the curve: discovery 0.871 vs. 0.742, validation 1 0.869 vs. 0.731, and validation 2 0.972 vs. 0.742; P < 0.01). Similar results were observed with a 13-metabolite panel at GW 17-19. Dysmetabolism is present early in pregnancy among individuals progressing to GDM. Multimetabolite panels in early pregnancy can predict GDM risk beyond conventional risk factors.

Understanding the role of SGLT2 inhibitors in glycogen storage disease type Ib: the experience of one UK centre

BACKGROUND

Glycogen storage disease type Ib (GSD Ib) is a severe disorder of carbohydrate metabolism due to bi-allelic variants in SLC37A4. It is associated with neutropaenia and neutrophil dysfunction, which has recently been attributed to the accumulation of 1,5-anhydroglucitol-6-phosphate (1,5AG6P) within neutrophils. Treatment with sodium-glucose co-transporter-2 (SGLT2) inhibitors, such as empagliflozin, is a novel therapy that reduces 1,5-anhydroglucitol (1,5AG) in plasma.

RESULTS

We report our experience in treating 8 paediatric GSD Ib patients with empagliflozin with a cumulative treatment time greater than 12 years. Treatment with a median dose of 5 mg (0.22 mg/kg height weight) of empagliflozin resulted in improvement in bowel health, growth, and laboratory parameters. Plasma 1,5AG levels reduced by a median of 78%. Baseline 1,5AG levels in our cohort were higher than in adult patients with GSD Ib. Hypoglycaemia on empagliflozin treatment occurred in 50% of our cohort.

CONCLUSION

We report the largest single centre cohort of GSD Ib patients treated with empagliflozin to date. Treatment with SGLT2 inhibitors is a novel and favourable treatment option for neutropaenia and neutrophil dysfunction in GSD Ib. We suggest a low starting dose of empagliflozin with careful titration due to the risk of hypoglycaemia. The interpretation of 1,5AG levels and their role in treatment monitoring is yet to be established, and requires ongoing research.

Recent Developments in Biomarkers for Diagnosis and Screening of Type 2 Diabetes Mellitus

PURPOSE OF REVIEW

Diabetes mellitus is a complex, chronic illness characterized by elevated blood glucose levels that occurs when there is cellular resistance to insulin action, pancreatic β-cells do not produce sufficient insulin, or both. Diabetes prevalence has greatly increased in recent decades; consequently, it is considered one of the fastest-growing public health emergencies globally. Poor blood glucose control can result in long-term micro- and macrovascular complications such as nephropathy, retinopathy, neuropathy, and cardiovascular disease. Individuals with diabetes require continuous medical care, including pharmacological intervention as well as lifestyle and dietary changes.

RECENT FINDINGS

The most common form of diabetes mellitus, type 2 diabetes (T2DM), represents approximately 90% of all cases worldwide. T2DM occurs more often in middle-aged and elderly adults, and its cause is multifactorial. However, its incidence has increased in children and young adults due to obesity, sedentary lifestyle, and inadequate nutrition. This high incidence is also accompanied by an estimated underdiagnosis prevalence of more than 50% worldwide. Implementing successful and cost-effective strategies for systematic screening of diabetes mellitus is imperative to ensure early detection, lowering patients' risk of developing life-threatening disease complications. Therefore, identifying new biomarkers and assay methods for diabetes mellitus to develop robust, non-invasive, painless, highly-sensitive, and precise screening techniques is essential. This review focuses on the recent development of new clinically validated and novel biomarkers as well as the methods for their determination that represent cost-effective alternatives for screening and early diagnosis of T2DM.

Using Metabolomics in Diabetes Management with Traditional Chinese Medicine: A Review

The incidence of diabetes worldwide continues to rise, placing a huge economic and medical burden on human society. More than 90% of diabetic cases are type 2 diabetes (T2D). At present, the pathogenesis of T2D is not yet fully understood. Metabolomics uses high-resolution analytical techniques (typically NMR and MS) to help identify biomarkers associated with the risk of T2D and reveal potential pathogenesis. Many metabolites such as branched-chain amino acids (BCAAs), aromatic amino acids, glycine, 2-hydroxybutyric acid (2-HB), lysophosphatidylcholine (LPC) (18:2), and trehalose have proven to be biomarkers of T2D. Insulin resistance (IR) induced by BCAA in T2D mice is related to the activation of mammalian target of rapamycin (mTOR) and phosphorylation of insulin receptor substrate-1 (IRS1). Incomplete LCFA [Formula: see text]-oxidation promote acylcarnitine byproduct accumulation and stimulates proinflammatory NF[Formula: see text]B-related pathways to inhibit insulin action. Traditional Chinese Medicine (TCM) presents unique advantages in the treatment of T2D. Multiple metabolites and metabolic pathways have been identified in the treatment of TCM, providing valuable biomarkers and novel targets for drug therapy and pharmacological mechanism. Therefore, this paper reviews the modern achievements of metabolomics in T2D research and the progress of TCM management in recent years, in order to provide valuable information for related research.

The role of metabolomics in personalized medicine for diabetes

Metabolomics is rapidly evolving omics technology in personalized medicine, it offers a new avenue for identification of multiple novel metabolic mediators of impaired glucose tolerance and dysglycemia. Liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy are most commonly used analytical methods in the field of metabolomics. Recent evidences showed that metabolomic profiles are link to the incidence of diabetes. In this review, an overview of metabolomics studies in diabetes revealed several diabetes-associated metabolites including 1,5-anhydroglycitol, branch chain amino acids, glucose, α-hydroxybutyric acid, 3-hydroundecanoyl-carnitine and phosphatidylcholine that could be potential biomarkers associated with diabetes. These identified metabolites can be used to develop personalized prognostics and diagnostic, and help in diabetes management.

What methods are being used to create an evidence base on the use of laboratory tests to monitor long-term conditions in primary care? A scoping review

BACKGROUND

Studies have shown unwarranted variation in test ordering among GP practices and regions, which may lead to patient harm and increased health care costs. There is currently no robust evidence base to inform guidelines on monitoring long-term conditions.

OBJECTIVES

To map the extent and nature of research that provides evidence on the use of laboratory tests to monitor long-term conditions in primary care, and to identify gaps in existing research.

METHODS

We performed a scoping review-a relatively new approach for mapping research evidence across broad topics-using data abstraction forms and charting data according to a scoping framework. We searched CINAHL, EMBASE and MEDLINE to April 2019. We included studies that aimed to optimize the use of laboratory tests and determine costs, patient harm or variation related to testing in a primary care population with long-term conditions.

RESULTS

Ninety-four studies were included. Forty percent aimed to describe variation in test ordering and 36% to investigate test performance. Renal function tests (35%), HbA1c (23%) and lipids (17%) were the most studied laboratory tests. Most studies applied a cohort design using routinely collected health care data (49%). We found gaps in research on strategies to optimize test use to improve patient outcomes, optimal testing intervals and patient harms caused by over-testing.

CONCLUSIONS

Future research needs to address these gaps in evidence. High-level evidence is missing, i.e. randomized controlled trials comparing one monitoring strategy to another or quasi-experimental designs such as interrupted time series analysis if trials are not feasible.

Secondary Metabolites in the Treatment of Diabetes Mellitus: A Paradigm Shift

Diabetes mellitus (DM) is a chronic, polygenic and non-infectious group of diseases that occurs due to insulin resistance or its low production by the pancreas and is also associated with lifelong damage, dysfunction and collapse of various organs. Management of diabetes is quite complex having many bodily and emotional complications and warrants efficient measures for prevention and control of the same. As per the estimates of the current and future diabetes prevalence, around 425 million people were diabetic in 2017 which is anticipated to rise up to 629 million by 2045. Various studies have vaguely proven the fact that several vitamins, minerals, botanicals and secondary metabolites demonstrate hypoglycemic activity in vivo as well as in vitro. Flavonoids, anthocyanin, catechin, lipoic acid, coumarin metabolites, etc. derived from herbs were found to elicit a significant influence on diabetes. However, the prescription of herbal compounds depend on various factors, including the degree of diabetes progression, comorbidities, feasibility, economics as well as their ADR profile. For instance, cinnamon could be a more favorable choice for diabetic hypertensive patients. Diabecon®, Glyoherb® and Diabeta Plus® are some of the herbal products that had been launched in the market for the favorable or adjuvant therapy of diabetes. Moreover, Aloe vera leaf gel extract demonstrates significant activity in diabetes. The goal of this review was to inscribe various classes of secondary metabolites, in particular those obtained from plants, and their role in the treatment of DM. Recent advancements in recognizing the markers which can be employed for identifying altered metabolic pathways, biomarker discovery, limitations, metabolic markers of drug potency and off-label effects are also reviewed.

Diabetes mellitus in chronic kidney disease: Biomarkers beyond HbA1c to estimate glycemic control and diabetes-dependent morbidity and mortality

Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD). Optimal glycemic control contributes to improved outcomes in patients with DM, particularly for microvascular damage, but blood glucose levels are too variable to provide an accurate assessment and instead markers averaging long-term glycemic load are used. The most established glycemic biomarker of long-term glycemic control is HbA1c. Nevertheless, HbA1c has pitfalls that limit its accuracy to estimate glycemic control, including the presence of altered red blood cell survival, hemoglobin glycation and suboptimal performance of HbA1c assays. Alternative methods to evaluate glycemic control in patients with DM include glycated albumin, fructosamine, 1-5 anhydroglucitol, continuous glucose measurement, self-monitoring of blood glucose and random blood glucose concentration measurements. Accordingly, our aim was to review the advantages and pitfalls of these methods in the context of CKD.

Paper-based 1,5-anhydroglucitol quantification using enzyme-based glucose elimination

The monosaccharide 1,5-anhydroglucitol (1,5-AG) is a known indicator of glucose levels. Conventional 1,5-AG quantification methods with enzyme-based sensors using pyranose oxidase (PROD) require elimination of interference from the sample (a laborious and time-consuming process), as PROD cannot distinguish 1,5-AG from other sugars. We developed a one-step paper-based sensor for detecting 1,5-AG using glucose oxidase, catalase, and mutarotase that eliminates excess glucose, which interferes with 1,5-AG detection. This sensor consists of two compartments for the quantification of glucose and 1,5-AG and reflects the concentration of these targets after reaction with water or spiked human urine. The limit of detection of the sensor was 0.9 mg dL-1 for glucose and 3.2 μg mL-1 for 1,5-AG.

Association between a biomarker of glucose spikes, 1,5-anhydroglucitol, and cancer mortality

INTRODUCTION

1,5-Anhydroglucitol (1,5-AG) is a biomarker of glucose spikes. To evaluate the effect of acute glucose excursions on cancer death, we clarified the association between 1,5-AG and cancer mortality among Japanese individuals with normal glucose tolerance.

RESEARCH DESIGN AND METHODS

We measured 1,5-AG in 6783 (2842 men, 3941 women) individuals with normal fasting and 2-hour plasma glucose who received a 75 g oral glucose tolerance test between 1994 and 2012. They were followed for mortality until August 2013. A systematic review of death certificates was used to confirm the cause of death. We divided the participants into four groups according to the quartile of 1,5-AG level at registration. We used Cox regression to clarify the association between 1,5-AG levels and cancer mortality with multivariate adjustment for possible confounders.

RESULTS

During the follow-up period (median, 10.0 years), 140 men and 109 women died of cancer. The HR for cancer mortality of the lowest quartile group was higher than that of the highest quartile group in men (HR, 2.62; 95% CI, 1.60 to 4.41) and in women (HR, 1.47; 95% CI, 0.88 to 2.47). These associations were not attenuated with further adjustment for HbA1c.

CONCLUSIONS

1,5-AG was associated with high risk of cancer mortality in Japanese men after adjustment for HbA1c.

Review of methods for detecting glycemic disorders

Prediabetes (intermediate hyperglycemia) consists of two abnormalities, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) detected by a standardized 75-gram oral glucose tolerance test (OGTT). Individuals with isolated IGT or combined IFG and IGT have increased risk for developing type 2 diabetes (T2D) and cardiovascular disease (CVD). Diagnosing prediabetes early and accurately is critical in order to refer high-risk individuals for intensive lifestyle modification. However, there is currently no international consensus for diagnosing prediabetes with HbA1c or glucose measurements based upon American Diabetes Association (ADA) and the World Health Organization (WHO) criteria that identify different populations at risk for progressing to diabetes. Various caveats affecting the accuracy of interpreting the HbA1c including genetics complicate this further. This review describes established methods for detecting glucose disorders based upon glucose and HbA1c parameters as well as novel approaches including the 1-hour plasma glucose (1-h PG), glucose challenge test (GCT), shape of the glucose curve, genetics, continuous glucose monitoring (CGM), measures of insulin secretion and sensitivity, metabolomics, and ancillary tools such as fructosamine, glycated albumin (GA), 1,5- anhydroglucitol (1,5-AG). Of the approaches considered, the 1-h PG has considerable potential as a biomarker for detecting glucose disorders if confirmed by additional data including health economic analysis. Whether the 1-h OGTT is superior to genetics and omics in providing greater precision for individualized treatment requires further investigation. These methods will need to demonstrate substantially superiority to simpler tools for detecting glucose disorders to justify their cost and complexity.

Effects of hydrogen-rich water prepared by alternating-current-electrolysis on antioxidant activity, DNA oxidative injuries, and diabetes-related markers

Hydrogen-rich water is conventionally prepared by direct current-electrolysis, but has been not or scarcely prepared by alternating current (AC)-electrolysis. The AC preparations from tap water for 20-30 minutes exhibit a dissolved hydrogen concentration of 1.55 mg/L, which was close to the theoretical maximum value of 1.6 mg/L. These preparations also displayed an oxidation-reduction potential of -270 mV (tap water: +576 mV) and pH of 7.7-7.8, being closer to physiological values of body fluids than general types of direct current-electrolytic hydrogen-rich water. We examined whether AC-electrolytic hydrogen-water is retained for hydrogen-abundance after boiling or for antioxidant abilities, and whether the oral administration of this water is clinically effective for diabetes and prevention against systemic DNA-oxidative injuries. 5,5-Dimethyl-1-pyrroline-N-oxide spin trapping and electron spin resonance revealed that the hydrogen-rich water generated by AC-electrolysis exhibited hydroxyl-radical-scavenging activities. Laser nanoparticle tracking method revealed that nanoparticle suspensions as abundant as 5.4 × 107/mL were efficiently retained (up to 3.5 × 107/mL) even after boiling for 10 minutes, being thermodynamically contrary to Henry's law. Oral intake of hydrogen-rich water, 1500 mL per day, lasted for 8 weeks in nine people with the diabetes-related serum markers beyond the normal ranges. The subjects exhibited significant tendencies for the decreased fasting blood glucose and fructosamine, and for the increased 1,5-anhydro-D-glucitol, concomitantly with significant decreases in urinary 8-hydroxy-2-deoxyguanosine contents and its rate of generation. Hydrogen-rich water prepared by AC-electrolysis may be effective in improving diverse diabetes-related markers and systemic DNA oxidative injuries through the formation of abundant heat-resistant nanobubbles and the increased hydrogen concentrations. The study protocol was officially approved by the Medical Ethics Committee of the Japanese Center for Anti-Aging Medical Sciences (approval No. 01S02) on September 15, 2009.

Vitreous humor endogenous compounds analysis for post-mortem forensic investigation

The chemical and biochemical analysis of bodily fluids after death is an important thanatochemical approach to assess the cause and time since death. Vitreous humor (VH) has been used as a biofluid for forensic purposes since the 1960s. Due to its established relevance in toxicology, a literature review highlighting the use of VH with an emphasis on endogenous compounds has not yet been undertaken. VH is a chemically complex aqueous solution of carbohydrates, proteins, electrolytes and other small molecules present in living organisms; this biofluid is useful tool for its isolated environment, preserved from bacterial contamination, decomposition, autolysis, and metabolic reactions. The post-mortem analysis of VH provides an important tool for the estimation of the post-mortem interval (PMI), which can be helpful in determining the cause of death. Consequently, the present review evaluates the recent chemical and biochemical advances with particular importance on the endogenous compounds present at the time of death and their modification over time, which are valuable for the PMI prediction and to identify the cause of death.

Endoscopic duodenal mucosal resurfacing improves glycaemic and hepatic indices in type 2 diabetes: 6-month multicentre results

Insulin resistance is a core pathophysiological defect underscoring type 2 diabetes mellitus (T2DM) and non-alcoholic fatty liver disease (NAFLD). Both conditions improve with duodenal exclusion surgery. Duodenal mucosal resurfacing (DMR) is an endoscopic intervention developed to treat metabolic disease which has been shown to improve glycaemia in patients with poorly controlled T2DM. Herein, we aimed to further analyse the effects of DMR on hepatic and metabolic parameters in this patient cohort.

METHODS

Eighty-five patients with T2DM who received endoscopic DMR treatment were enrolled from 5 centres and followed up for 6 months. We assessed safety in all patients. Efficacy was evaluated in patients who received at least 9 cm of duodenal ablation (n = 67). Endpoints included HbA1c, fasting plasma glucose, weight and aminotransferase levels. Metabolomic analysis was conducted in a subgroup (n = 14). Data were analysed using paired t test or ANOVA for repeated measures with Bonferroni correction and correction for initial weight loss if applicable.

RESULTS

The DMR procedure was completed with no intraprocedural complications in the entire cohort. HbA1c was lower 6 months after DMR than at baseline (7.9 ± 0.2% vs. 9.0 ± 0.2% [mean ± SE], p ≪0.001). Fasting plasma glucose was also significantly lower 6 months after DMR compared to baseline (161 ± 7 mg/dl vs. 189 ± 6 mg/dl, p = 0.005). Body weight decreased slightly. At 6 months, alanine aminotransferase had decreased from 41 ± 3 IU/L to 29 ± 2 IU/L (p ≪0.001) and aspartate aminotransferase had decreased from 30 ± 2 IU/L to 23 ± 1 IU/L (p ≪0.001). Metabolomic analysis demonstrated that DMR had key lipid-lowering, insulin-sensitizing and anti-inflammatory effects, as well as increasing antioxidant capacity. Mean FIB-4 was also markedly decreased.

CONCLUSION

Hydrothermal ablation of the duodenum by DMR elicits a beneficial metabolic response in patients with T2DM. DMR also improves hepatic indices, potentially through an insulin-sensitizing mechanism. These encouraging data deserve further evaluation in randomized controlled trials.

LAY SUMMARY

Hydrothermal duodenal mucosal resurfacing (DMR) is an endoscopic technique designed to treat metabolic disease through ablation of the duodenal mucosa. DMR is a safe procedure which improves glycaemia and hepatic indices in patients with type 2 diabetes mellitus. DMR is an insulin-sensitizing intervention which can be complementary to lifestyle intervention approaches and pharmacological treatments aimed at preserving the pancreas and liver from failure. DMR is a potential therapeutic solution for patients with type 2 diabetes and fatty liver disease.

Immunological evidence for in vivo production of novel advanced glycation end-products from 1,5-anhydro-D-fructose, a glycogen metabolite

The anhydrofructose pathway is an alternate pathway for glycogen degradation by α-1,4-glucan lyase. The sugar 1,5-anhydro-D-fructose (1,5-AF) acts as the central intermediate of this pathway, but its physiological role of in mammals is unclear. Glycation reactions forming advanced glycation end-products (AGEs) are important in the development of complications of diabetes mellitus. We hypothesized that 1,5-AF may contribute to cellular damage by forming 1,5-AF-derived AGEs (AF-AGEs) with intracellular proteins. To clarify the role of 1,5-AF in protein modification, we created a novel antibody targeting AF-AGEs. Serum albumin modified by AF-AGEs was prepared by incubating rabbit serum albumin (RSA) or bovine serum albumin (BSA) with 1,5-AF. After immunizing rabbits with AF-AGEs-RSA, affinity chromatography of anti-AF-AGE antiserum was performed on a Sepharose 4B column coupled with AF-AGEs-BSA or N-(carboxymethyl)/N-(carboxyethyl)lysine-BSA. A novel immunopurified anti-AF-AGE antibody was obtained and was characterized using a competitive enzyme-linked immunosorbent assay. Then an AF-AGEs assay was established using this immunopurified antibody. This assay was able to detect AF-AGEs in human and animal serum samples. Finally, intracellular accumulation of AF-AGEs was shown to be associated with damage to cultured hepatocytes (HepG2 cells). This is the first report about in vivo detection of AF-AGEs with a novel structural epitope.

The Association of Late-Life Diabetes Status and Hyperglycemia With Incident Mild Cognitive Impairment and Dementia: The ARIC Study

OBJECTIVE

We sought to examine associations in older adults among diabetes, glycemic control, diabetes duration, and biomarkers of hyperglycemia with incident mild cognitive impairment (MCI) and incident dementia.

RESEARCH DESIGN AND METHODS

We conducted a prospective analysis of 5,099 participants from the Atherosclerosis Risk in Communities (ARIC) Study who attended the fifth (2011-2013) exam. Cognitive status was assessed during follow-up via telephone calls, death certificate codes, surveillance, and a follow-up examination (2016-2017). We defined incident cognitive impairment as incident MCI or incident dementia in persons dementia-free at the index examination; we also examined each outcome separately. Diabetes was defined using self-report, medications, or HbA1c ≥6.5%; poor glycemic control in persons with diabetes was defined as HbA1c ≥7%. We examined the following biomarkers of hyperglycemia: HbA1c, fructosamine, glycated albumin, and 1,5-anhydroglucitol.

RESULTS

Mean age at baseline was 76 years, 59% were female, and 21% were black. Diabetes (hazard ratio [HR] 1.14 [95% CI 1.00, 1.31]), poor glycemic control in persons with diabetes (HR 1.31 [95% CI 1.05, 1.63]), and longer diabetes duration (≥5 vs. <5 years; HR 1.59 [95% CI 1.23, 2.07]) were significantly associated with incident cognitive impairment. We found a J-shaped association between HbA1c and incident dementia. Glycated albumin and fructosamine were also associated with incident dementia, independently of HbA1c. HbA1c and fructosamine were also associated with incident MCI.

CONCLUSIONS

Diabetes status, poor glycemic control, and longer diabetes duration were associated with worse cognitive outcomes over a median follow-up of 5 years.

Impact of serum 1,5-anhydro-D-glucitol level on the prediction of severe coronary artery calcification: an intravascular ultrasound study

BACKGROUND

A low 1,5-anhydro-D-glucitol (AG) blood level is considered a clinical marker of postprandial hyperglycemia. Previous studies reported that 1,5-AG levels were associated with vascular endothelial dysfunction and coronary artery disease (CAD). However, the association between 1,5-AG levels and coronary artery plaque in patients with CAD is unclear.

METHODS

This study included 161 patients who underwent percutaneous coronary intervention for CAD. The culprit plaque characteristics and the extent of coronary calcification, which was measured by the angle of its arc, were assessed by preintervention intravascular ultrasound (IVUS). Patients with chronic kidney disease or glycosylated hemoglobin ≥ 7.0 were excluded. Patients were divided into 2 groups according to serum 1,5-AG levels (< 14.0 μg/mL vs. ≥ 14 μg/mL).

RESULTS

The total atheroma volume and the presence of IVUS-attenuated plaque in the culprit lesions were similar between groups. Calcified plaques were frequently observed in the low 1,5-AG group (p = 0.06). Compared with the high 1,5-AG group, the low 1,5-AG group had significantly higher median maximum calcification (144° vs. 107°, p = 0.03) and more frequent calcified plaques with a maximum calcification angle of ≥ 180° (34.0% vs. 13.2%, p = 0.003). Multivariate logistic regression analysis showed that a low 1,5-AG level was a significant predictor of a greater calcification angle (> 180°) (OR 2.64, 95% CI 1.10-6.29, p = 0.03).

CONCLUSIONS

Low 1,5-AG level, which indicated postprandial hyperglycemia, was associated with the severity of coronary artery calcification. Further studies are needed to clarify the effects of postprandial hyperglycemia on coronary artery calcification.

An Update on Measures of Preoperative Glycemic Control

Glycemic control represents a modifiable preoperative risk factor in surgery. Traditionally, hemoglobin A1c (HbA1c) and plasma glucose are utilized as measures of glycemic control. However, studies show mixed results regarding the ability of these conventional measures to predict adverse surgical outcomes. This may be explained by the time window captured by HbA1c and serum glucose: long-term and immediate glycemic control, respectively. Fructosamine, glycosylated albumin, and 1,5-anhydroglucitol constitute alternative metrics of glycemic control that are of growing interest but are underutilized in the field of surgery. These nontraditional measures reflect the temporal variations in glycemia over the preceding days to weeks. Therefore, they may more accurately reflect glycemic control within the time window that most significantly affects surgical outcomes. Additionally, these alternative measures are predictive of negative outcomes, even in the nondiabetic population and in patients with chronic renal disease and anemia, for whom HbA1c performs poorly. Adopting these newer metrics of glycemia may enhance the value of preoperative evaluation, such that the effectiveness of any preoperative glycemic control interventions can be assessed, and adverse outcomes associated with hyperglycemia better predicted. The goal of this review is to provide an update on the preoperative management of glycemia and to describe alternative metrics that may improve our ability to predict and control for the negative outcomes associated with poor glycemic control.

A decision algorithm to identify patients with high probability of monogenic diabetes due to HNF1A mutations

PURPOSE

To investigate the utility of biomarkers of maturity-onset diabetes of the young (MODY), high-sensitivity C-reactive protein (hsCRP), and 1,5-anhydroglucitol (1,5-AG) in conjunction with other clinical and laboratory features to improve diagnostic accuracy and provide a diagnostic algorithm for HNF1A MODY.

METHODS

We examined 77 patients with HNF1A MODY, 88 with GCK MODY mutations, 99 with type 1 diabetes, and 92 with type 2 diabetes. In addition to 1,5-AG and hsCRP, we considered body mass index (BMI), fasting glucose, and fasting serum C-peptide as potential biomarkers. Logistic regression and receiver operating characteristic curves were used in marker evaluation.

RESULTS

Concentration of hsCRP was lowest in HNF1A MODY (0.51 mg/l) and highest in type 2 diabetes (1.33 mg/l). The level of 1,5-AG was lowest in type 1 diabetes and HNF1A MODY, 3.8 and 4.7 μg/ml, respectively, and highest (11.2 μg/ml) in GCK MODY. In the diagnostic algorithm, we first excluded patients with type 1 diabetes based on low C-peptide (C-statistic 0.98) before using high BMI and C-peptide to identify type 2 diabetes patients (C-statistic 0.92). Finally, 1,5-AG and hsCRP in conjunction yielded a C-statistic of 0.86 in discriminating HNF1A from GCK MODY. We correctly classified 92.9% of patients with type 1 diabetes, 84.8% with type 2 diabetes, 64.9% HNF1A MODY, and 52.3% GCK MODY patients.

CONCLUSIONS

Plasma 1,5-AG and serum hsCRP do not discriminate sufficiently HNF1A MODY from common diabetes types, but could be potentially useful in prioritizing Sanger sequencing of HNF1A gene.

1,5 Anhydroglucitol in gestational diabetes mellitus

OBJECTIVE

1,5 Anhydroglucitol (1,5 AG) is reported to be a more sensitive marker of glucose variability and short-term glycemic control (1-2 weeks) in patients with type1 and type 2 diabetes. However, the role of 1,5 AG in gestational diabetes mellitus (GDM) is not clear. We estimated the serum levels of 1,5 AG in pregnant women with and without GDM.

METHODS

We recruited 220 pregnant women, 145 without and 75 with GDM visiting antenatal clinics in Tamil Nadu in South India. Oral glucose tolerance tests (OGTTs) were carried out using 82.5 g oral glucose (equivalent to 75 g of anhydrous glucose) and GDM was diagnosed based on the International Association of Diabetes and Pregnancy Study Group criteria. Serum 1,5 AG levels were measured using an enzymatic, colorimetric assay kit (Glycomark®, New York, NY). Receiver operating characteristic (ROC) curves were used to identify 1,5 AG cut-off points to identify GDM.

RESULTS

The mean levels of the 1,5 AG were significantly lower in women with GDM (11.8 ± 5.7 μg/mL, p < 0.001) compared to women without GDM (16.2 ± 6.2 μg/mL). In multiple logistic regression analysis, 1.5 AG showed a significant association with GDM (odds ratio [OR]: 0.876, 95% confidence interval [CI]: 0.812-0.944, p < 0.001) after adjusting for potential confounders. 1,5 AG had a C statistic of 0.693 compared to Fructosamine (0.671) and HbA1c (0.581) for identifying GDM. A 1,5 AG cut-off of 13.21 μg/mL had a C statistic of 0.6936 (95% CI: 0.6107-0.7583, p < 0.001), sensitivity of 67.6%, and specificity of 65.3% to identify GDM.

CONCLUSION

1,5AG levels are lower in pregnant women with GDM compared to individuals without GDM.

A metabolome-wide characterization of the diabetic phenotype in ZDF rats and its reversal by pioglitazone

Type 2 diabetes (T2D) is a complex metabolic disease associated with alterations in glucose, lipid and protein metabolism. In order to characterize the biochemical phenotype of the Zucker diabetic fatty (ZDF) rat, the most common animal model for the study of T2D, and the impact of the insulin sensitizer pioglitazone, a global, mass spectrometry-based analysis of the metabolome was conducted. Overall, 420 metabolites in serum, 443 in the liver and 603 in the intestine were identified at study end. In comparison to two control groups, obese diabetic ZDF rats showed characteristic metabolic signatures that included hyperglycemia, elevated β-oxidation, dyslipidemia—featured by an increase in saturated and monounsaturated fatty acids and a decrease of medium chain and of polyunsaturated fatty acids in serum–and decreased amino acid levels, consistent with their utilization in hepatic gluconeogenesis. A 13-week treatment with the PPARγ agonist pioglitazone reversed most of these signatures: Pioglitazone improved glycemic control and the fatty acid profile, elevated amino acid levels in the liver, but decreased branched chain amino acids in serum. The hitherto most comprehensive metabolic profiling study identified a biochemical blueprint for the ZDF diabetic model and captured the impact of genetic, nutritional and pharmacological perturbations. The in-depth characterization on the molecular level deepens the understanding and further validates the ZDF rat as a suitable preclinical model of diabetes in humans.

Progress in Metabonomics of Type 2 Diabetes Mellitus

With the improvement of living standards and a change in lifestyle, the incidence of type 2 diabetes mellitus (T2DM) is increasing. Its etiology is too complex to be completely understand yet. Metabonomics techniques are used to study the changes of metabolites and metabolic pathways before and after the onset of diabetes and make it more possible to further understand the pathogenesis of T2DM and improve its prediction, early diagnosis, and treatment. In this review, we summarized the metabonomics study of T2DM in recent years and provided a theoretical basis for the study of pathogenesis and the effective prevention and treatment of T2DM.

Reference intervals for serum 1,5-anhydroglucitol in children, adolescents, adults, and pregnant women

BACKGROUND

1,5-anhydroglucitol (1,5-AG) is a validated marker of short-term glycemic control. We determined the reference intervals of 1,5-AG in different age groups and during pregnancy.

METHODS

Blood samples were collected from 2303 Euro-Brazilian healthy subjects: 580 children, 496 adolescents, 922 adults matched by age and sex, and 305 pregnant women in four gestational periods. Serum 1,5-AG was measured using an enzymatic reagent in an automated system.

RESULTS

The calculated reference intervals (nonparametric, 2.5th-97.5th) for males and females were, respectively: children, 96-302 and 89-277 μmol/l; adolescents, 84-311 and 79-277 μmol/l; and adults, 80-260 and 62-241 μmol/l. Males consistently showed significantly higher concentrations than females. 1,5-AG reference intervals in pregnant women were 56-298 μmol/l at <23 weeks gestation (n = 110), 37-166 μmol/l at 24-28 weeks gestation (n = 106), 34-155 μmol/l at 29-32 weeks gestation (n = 52), and 33-246 μmol/l at >32 weeks gestation (n = 37). No significant differences in 1,5-AG concentration were observed between non-pregnant and pregnant women at <23 weeks of gestation. A negative correlation (r = -0.287; p < .001) between 1,5-AG concentration and age was observed.

CONCLUSIONS

The reference intervals for 1,5-AG were affected by sex and age.

Assessing the Associations of Blood Metabolites With Osteoporosis: A Mendelian Randomization Study

Context

Osteoporosis is a metabolic bone disease. The effect of blood metabolites on the development of osteoporosis remains elusive.

Objective

To explore the relationship between blood metabolites and osteoporosis.

Design and Methods

We used 2286 unrelated white subjects for the discovery samples and 3143 unrelated white subjects from the Framingham Heart Study (FHS) for the replication samples. The bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry. Genome-wide single nucleotide polymorphism (SNP) genotyping was performed using Affymetrix Human SNP Array 6.0 (for discovery samples) and Affymetrix SNP 500K and 50K array (for FHS replication samples). The SNP sets significantly associated with blood metabolites were obtained from a reported whole-genome sequencing study. For each subject, the genetic risk score of the metabolite was calculated from the genotype data of the metabolite-associated SNP sets. Pearson correlation analysis was conducted to evaluate the potential effect of blood metabolites on the variations in bone phenotypes; 10,000 permutations were conducted to calculate the empirical P value and false discovery rate.

Results

We analyzed 481 blood metabolites. We identified multiple blood metabolites associated with hip BMD, such as 1,5-anhydroglucitol (Pdiscovery < 0.0001; Preplication = 0.0361), inosine (Pdiscovery = 0.0018; Preplication = 0.0256), theophylline (Pdiscovery = 0.0048; Preplication = 0.0433, gamma-glutamyl methionine (Pdiscovery = 0.0047; Preplication = 0.0471), 1-linoleoyl-2-arachidonoyl-GPC (18:2/20:4n6; Pdiscovery = 0.0018; Preplication = 0.0390), and X-12127 (Pdiscovery = 0.0002; Preplication = 0.0249).

Conclusions

Our results suggest a modest effect of blood metabolites on the variations of BMD and identified several candidate blood metabolites for osteoporosis.

Evaluation of 1,5-anhydro-d-glucitol in clinical and forensic urine samples

Because of the lack of characteristic morphological findings post mortem diagnosis of diabetes mellitus and identification of diabetic coma can be complicated. 1,5-Anhydroglucitol (1,5-AG), the 1-deoxy form of glucose, competes with glucose for renal reabsorption. Therefore low serum concentrations of 1,5-AG, reflect hyperglycemic excursions over the prior 1-2 weeks in diabetic patients. Next to clinical applications determination of 1,5-AG can also be used in forensic analysis. To investigate the elimination of 1,5-AG, a liquid chromatographic-mass spectrometric method for the determination of 1,5-AG and creatinine in urine was developed and validated according to international guidelines. To evaluate ante mortem concentrations of 1,5-AG spot urine samples of 30 healthy subjects, 46 type 1 and 46 type 2 diabetic patients were analyzed. 1,5-AG urine concentrations of diabetic patients were significantly (p<0.001) lower (mean: 1.54μg/ml, n=92) compared to concentrations of healthy subjects (mean: 4.76μg/ml, n=30) which led to the idea that 1,5-AG urine concentrations post mortem might help in the interpretation of a diabetic coma post mortem. Urine of 47 deceased non-diabetics, 37 deceased diabetic and 9 cases of diabetic coma were measured. Comparison of blood and urine 1,5-AG concentrations in clinic samples (linear, R²=0.13) and forensic samples (linear, R²=0.02) showed no correlation. Urinary levels of 1,5-AG in deceased diabetic (mean 6.9μg/ml) and in non-diabetic patients (mean 6.3μg/ml) did not show a significant difference (p=0.752). However, urinary 1,5-AG concentrations in deceased due to diabetic coma (mean: 1.7μg/ml) were significantly lower than in non-diabetic (mean: 6.3μg/ml, p=0.039) and lower than in diabetic cases (mean: 4.7μg/ml, p=0.058). The determination of a reliable cut-off for the differentiation of diabetic to diabetic coma cases was not possible. Normalization of urinary 1,5-AG concentrations with the respective creatinine concentrations did not show any gain of information. In clinical (serum) and forensic blood samples a significant difference between all groups could be detected (p<0.05). Comparison of blood and urine 1,5-AG concentrations in clinical samples (linear, R²=0.13) and forensic samples (linear, R²=0.02) showed no correlation.

Low 1,5-anhydroglucitol levels are associated with long-term cardiac mortality in acute coronary syndrome patients with hemoglobin A1c levels less than 7.0

BACKGROUND

Diabetes mellitus is considered an important risk factor for cardiovascular diseases. High hemoglobin A1c (HbA1c) levels, which indicate poor glycemic control, have been associated with occurrence of cardiovascular diseases. There are few parameters which can predict cardiovascular risk in patients with well-controlled diabetes. Low 1,5-anhydroglucitol (1,5-AG) levels are considered a clinical marker of postprandial hyperglycemia. We hypothesized that low 1,5-AG levels could predict long-term mortality in acute coronary syndrome (ACS) patients with relatively low HbA1c levels.

METHODS

The present study followed a retrospective observational study design. We enrolled 388 consecutive patients with ACS admitted to the cardiac intensive care unit at the Juntendo University Hospital from January 2011 to December 2013. Levels of 1,5-AG were measured immediately before emergency coronary angiography. Patients with early stent thrombosis, no significant coronary artery stenosis, malignancy, liver cirrhosis, a history of gastrectomy, current steroid treatment, moderately to severely reduced kidney function (estimated glomerular filtration rate < 45 ml/min/1.73 m2; chronic kidney disease stage 3B, 4, and 5), HbA1c levels ≥ 7.0%, and those who received sodium glucose co-transporter 2 inhibitor therapy were excluded.

RESULTS

During the 46.9-month mean follow-up period, nine patients (4.5%) died of cardiovascular disease. The 1,5-AG level was significantly lower in the cardiac death group compared with that in the survivor group (12.3 ± 5.3 vs. 19.2 ± 7.7 µg/ml, p < 0.01). Kaplan-Meier survival analysis showed that low 1,5-AG levels were associated with cardiac mortality (p = 0.02). Multivariable Cox regression analysis showed that 1,5-AG levels were an independent predictor of cardiac mortality (hazard ratio 0.76; 95% confidence interval 0.41-0.98; p = 0.03).

CONCLUSION

Low 1,5-AG levels, which indicate postprandial hyperglycemia, predict long-term cardiac mortality even in ACS patients with HbA1c levels < 7.0%.

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.

High fasting insulin concentrations may be a pivotal predictor for the severity of hepatic fibrosis beyond the glycemic status in non-alcoholic fatty liver disease patients before development of diabetes mellitus

BACKGROUND

Insulin resistance and type 2 diabetes mellitus (T2DM) contribute to the progression of non-alcoholic fatty liver disease (NAFLD). However, the relationship between glucose metabolic factors and the histological severity in NAFLD patients before development of T2DM is not well known.

METHODS

In 103 biopsy-proven NAFLD patients (68 men and 35 women) with hemoglobin A1c of <6.5% and fasting blood glucose of <126 mg/dL, we investigated whether glucose metabolic factors influenced the severity of hepatic fibrosis without prior known T2DM.

RESULTS

Female gender, age, serum aspartate aminotransferase, the aspartate aminotransferase/alanine aminotransferase ratio, fasting immunoreactive insulin (f-IRI), homeostasis model assessment - insulin resistance, hemoglobin A1c, hyaluronic acid, and type IV collagen 7 s were significantly higher, and 1,5-anhydroglucitol was significantly lower, in the fibrosis stage F3 group than in the F0-2 group. Multiple logistic regression analysis showed that only f-IRI (P = 0.006; odds ratio, 1.15151; 95% confidence interval, 1.04198-1.27254) was significantly indicated as a predictive factor for F3. As determined by both forward and backward stepwise selection analyses to optimize the model, f-IRI (P = 0001; odds ratio, 1.16788) remained an independent predictive factor for F3. To discriminate the F3 group from the F0-2 group, the area under the receiver operating characteristic curves showed that fasting insulin was 0.7219, and the best cut-off value of f-IRI was 13.2 μU/mL in the receiver operating characteristic curve analysis.

CONCLUSIONS

High fasting insulin concentrations may be a pivotal glucose metabolic predictor for the severity of hepatic fibrosis beyond the glycemic status in NAFLD patients before development of T2DM.

Effects of 1,5-anhydroglucitol on postprandial blood glucose and insulin levels and hydrogen excretion in rats and healthy humans

The inhibition by 1,5-anhydro-d-glucitol (1,5-AG) was determined on disaccharidases of rats and humans. Then, the metabolism and fate of 1,5-AG was investigated in rats and humans. Although 1,5-AG inhibited about 50 % of sucrase activity in rat small intestine, the inhibition was less than half of d-sorbose. 1,5-AG strongly inhibited trehalase and lactase, whereas d-sorbose inhibited them very weakly. 1,5-AG noncompetitively inhibited sucrase. The inhibition of 1,5-AG on sucrase and maltase was similar between humans and rats. 1,5-AG in serum increased 30 min after oral administration of 1,5-AG (600 mg) in rats, and mostly 100 % of 1,5-AG was excreted into the urine 24 h after administration. 1,5-AG in serum showed a peak 30 min after ingestion of 1,5-AG (20 g) by healthy subjects, and decreased gradually over 180 min. About 60 % of 1,5-AG was excreted into the urine for 9 h following ingestion. Hydrogen was scarcely excreted in both rats and humans 24 h after administration of 1,5-AG. Furthermore, 1,5-AG significantly suppressed the blood glucose elevation, and hydrogen excretion was increased following the simultaneous ingestion of sucrose and 1,5-AG in healthy subjects. 1,5-AG also significantly suppressed the blood glucose elevation following the simultaneous ingestion of glucose and 1,5-AG; however, hydrogen excretion was negligible. The available energy of 1,5-AG, which is absorbed readily from the small intestine and excreted quickly into the urine, is 0 kJ/g (0 kcal/g). Furthermore, 1,5-AG might suppress the blood glucose elevation through the inhibition of sucrase, as well as intestinal glucose absorption.

A computational model of 1,5-AG dynamics during pregnancy

The importance of 1,5‐anhydroglucitol (1,5‐AG) as an intermediate biomarker for diabetic pregnancy is multi‐fold: (1) it serves as a reliable indicator of moderate‐level glycemic control, especially during early gestation; (2) it has been associated with increased risk of diabetes, independent of HbA1c and fasting glucose; and (3) it is an independent risk factor for the development of eclampsia during pregnancy. However, the clinical use of this biomarker during pregnancy has been underutilized due to physiological changes in glomerular filtration rate, plasma volume, and other hemodynamic parameters which have been hypothesized to bias gestational serum 1,5‐AG concentrations. Here, we develop an in‐silico model of gestational 1,5‐AG by combining pre‐existing physiological data in the literature with a two‐compartment mathematical model, building off of a previous kinetic model described by Stickle and Turk (1997) Am. J. Physiol., 273, E821. Our model quantitatively characterizes how renal and hemodynamic factors impact measured 1,5‐AG during normal pregnancy and during pregnancy with gestational diabetes and diabetes mellitus. During both normal and diabetic pregnancy, we find that a simple two‐compartment model of 1,5‐AG kinetics, with all parameters but reabsorption fraction adjusted for time in pregnancy, efficiently models 1,5‐AG kinetics throughout the first two trimesters. Allowing reabsorption fraction to decrease after 25 weeks permits parameters closer to expected physiological values during the last trimester. Our quantitative model of 1,5‐AG confirms the involvement of hypothesized renal and hemodynamic mechanisms during pregnancy, clarifying the expected trends in 1,5‐AG to aid clinical interpretation. Further research and data may elucidate biological changes during the third trimester that account for the drop in 1,5‐AG concentrations, and clarify physiological differences between diabetes subtypes during pregnancy.

Insulin induces a shift in lipid and primary carbon metabolites in a model of fasting-induced insulin resistance

INTRODUCTION

Prolonged fasting in northern elephant seals (NES) is characterized by a reliance on lipid metabolism, conservation of protein, and reduced plasma insulin. During early fasting, glucose infusion previously reduced plasma free fatty acids (FFA); however, during late-fasting, it induced an atypical elevation in FFA despite comparable increases in insulin during both periods suggestive of a dynamic shift in tissue responsiveness to glucose-stimulated insulin secretion.

OBJECTIVE

To better assess the contribution of insulin to this fasting-associated shift in substrate metabolism.

METHODS

We compared the responses of plasma metabolites (amino acids (AA), FFA, endocannabinoids (EC), and primary carbon metabolites (PCM)) to an insulin infusion (65 mU/kg) in early- and late-fasted NES pups (n = 5/group). Plasma samples were collected prior to infusion (T0) and at 10, 30, 60, and 120 min post-infusion, and underwent untargeted and targeted metabolomics analyses utilizing a variety of GC-MS and LC-MS technologies.

RESULTS

In early fasting, the majority (72%) of metabolite trajectories return to baseline levels within 2 h, but not in late fasting indicative of an increase in tissue sensitivity to insulin. In late-fasting, increases in FFA and ketone pools, coupled with decreases in AA and PCM, indicate a shift toward lipolysis, beta-oxidation, ketone metabolism, and decreased protein catabolism. Conversely, insulin increased PCM AUC in late fasting suggesting that gluconeogenic pathways are activated. Insulin also decreased FFA AUC between early and late fasting suggesting that insulin suppresses triglyceride hydrolysis.

CONCLUSION

Naturally adapted tolerance to prolonged fasting in these mammals is likely accomplished by suppressing insulin levels and activity, providing novel insight on the evolution of insulin during a condition of temporary, reversible insulin resistance.

Serum 1,5-anhydroglucitol level as a screening tool for diabetes mellitus in a community-based population at high risk of diabetes

AIMS

Early diagnosis of diabetes yields significant clinical benefits; however, currently available diagnostic tools for community-based population are limited. This study aimed to assess the value of serum 1,5-anhydroglucitol (1,5-AG) for the diagnosis and screening of diabetes mellitus in a community-based population at high risk of diabetes.

METHODS

In this diagnostic test, 1170 participants underwent a 75-g oral glucose tolerance test. Venous blood samples were collected for fasting blood glucose (FBG), 2-h postprandial blood glucose (PBG), and glycosylated hemoglobin A1c (HbA1c) measurements. Serum 1,5-AG levels were detected by the GlycoMark assay, and a receiver operating characteristic (ROC) curve was generated to assess their diagnostic value for diabetes.

RESULTS

A total of 298 adults were diagnosed with diabetes, indicating a prevalence of 25.47%. Partial Pearson correlation analysis adjusted for age and body mass index showed that serum 1,5-AG level was negatively correlated with FBG, PBG, and HbA1c (all P < 0.01). Areas under the curves (AUCs) for serum 1,5-AG, FBG, PBG, and HbA1c in identifying diabetes were 0.920, 0.874, 0.933, and 0.887, respectively. According to the ROC curve, the optimal cutoff value of serum 1,5-AG for diagnosing diabetes was 11.18 μg/ml, which yielded a sensitivity of 92.6% and a specificity of 82.3%, respectively. Comparisons between 1,5-AG and HbA1c showed that both the AUC and sensitivity of 1,5-AG were higher than those of HbA1c (both P < 0.01).

CONCLUSIONS

Serum 1,5-AG is a simple and effective marker with high sensitivity and specificity for identifying diabetes in populations at high risk of diabetes.

Repeated 3-minute stair climbing-descending exercise after a meal over 2 weeks increases serum 1,5-anhydroglucitol levels in people with type 2 diabetes

[Purpose] The purpose of this study was to examine the hypoglycemic effect of a postprandial exercise program using brief stair climbing-descending exercise in people with type 2 diabetes. [Subjects and Methods] Seven males with uncomplicated type 2 diabetes (age 68.0 ± 3.7 years) performed two sets of stair climbing-descending exercise 60 and 120 min after each meal for the first 2 weeks but not for the following 2 weeks. Each set of exercise comprised 3-min of continuous repetition of climbing briskly to the second floor followed by slow waking down to the first floor in their home. A rest period of 1–2 min was allowed between each set. [Results] Serum 1,5-anhydroglucitol level was significantly higher by 11.5% at the end of the 2-week exercise period than at the baseline. By contrast, the 1,5-anhydroglucitol level at the end of the following 2-week period did not differ from the baseline value. Fasting blood glucose level and insulin resistance index at the end of the exercise period did not differ from the baseline value. [Conclusion] Repeated 3-min bouts of stair climbing-descending exercise after a meal may be a promising method for improving postprandial glycemic control in people with type 2 diabetes.

Key elements of metabolomics in the study of biomarkers of diabetes

Metabolomics is instrumental in the analysis of disease mechanisms and biomarkers of disease. The human metabolome is influenced by genetics and environmental interactions and reveals characteristic signatures of disease. Population studies with metabolomics require special study designs and care needs to be taken with pre-analytics. Gas chromatography coupled to mass spectrometry, liquid chromatography coupled to mass spectrometry or NMR are popular techniques used for metabolomic analyses in human cohorts. Metabolomics has been successfully used in the biomarker search for disease prediction and progression, for analyses of drug action and for the development of companion diagnostics. Several metabolites or metabolite classes identified by metabolomics have gained much attention in the field of diabetes research in the search for early disease detection, differentiation of progressor types and compliance with medication. This review summarises a presentation given at the 'New approaches beyond genetics' symposium at the 2015 annual meeting of the EASD. It is accompanied by another review from this symposium by Bernd Mayer (DOI: 10.1007/s00125-016-4032-2 ) and an overview by the Session Chair, Leif Groop (DOI: 10.1007/s00125-016-4014-4 ).

Low and exacerbated levels of 1,5-anhydroglucitol are associated with cardiovascular events in patients after first-time elective percutaneous coronary intervention

Background

Postprandial hyperglycemia plays an important role in the pathogenesis of coronary artery disease and cardiovascular events. Serum 1,5-anhydroglucitol (1,5-AG) levels are known to be a clinical marker of postprandial hyperglycemia. However, the impact of 1,5-AG level on cardiovascular events has not been fully investigated.

Methods

We enrolled 240 consecutive patients who had undergone first-time elective percutaneous coronary intervention (PCI) with follow-up angiography within 1 year. We excluded patients with a history of acute coronary syndrome, advanced chronic kidney disease (estimated glomerular filtration rate <30 mL/min/1.73 m²), or uncontrolled diabetes mellitus (HbA1c ≥7.0 %). Fasting blood glucose (FBS), HbA1c, and 1,5-AG levels were measured prior to PCI and at the time of follow-up angiography. Clinical events, including target lesion revascularization, target vessel revascularization, and revascularization of new lesions, were evaluated.

Results

Subjects were divided into two groups according to clinical outcomes: the Event (+) group (n = 40) and the Event (−) group (n = 200). No significant differences were observed, except for the number of diseased vessels and the prevalence of statin use, in baseline clinical characteristics between the two groups. Serum levels of 1,5-AG at follow-up were significantly lower in the Event (+) group than in the Event (−) group (P = 0.02). A significant reduction in 1,5-AG level from baseline to follow-up was observed in the Event (+) group compared with the Event (−) group (P = 0.04). The association between 1,5-AG levels at follow-up and clinical events remained significant after adjustment for independent variables, including FBS and HbA1c levels (P = 0.04).

Conclusions

Low and exacerbated levels of 1,5-AG were associated with cardiovascular events in the present study, indicating that postprandial hyperglycemia is an important risk factor for adverse clinical events even in patients with HbA1c < 7.0 %, following first-time elective PCI.

Association of a Biomarker of Glucose Peaks, 1,5-Anhydroglucitol, With Subclinical Cardiovascular Disease

OBJECTIVE

1,5-Anhydroglucitol (1,5-AG) is a biomarker of glucose peaks and has been associated with clinical cardiovascular disease. However, the association between 1,5-AG and subclinical cardiovascular disease is unknown. We investigated the association of 1,5-AG with subclinical myocardial damage (assessed by high-sensitivity cardiac troponin T [hs-cTnT]) and atherosclerosis (assessed by carotid intima-media thickness [CIMT] and carotid plaque).

RESEARCH DESIGN AND METHODS

We measured 1,5-AG, hs-cTnT, CIMT, and carotid plaque among 10,072 people without diabetes and 681 with diabetes who attended the second examination of the Atherosclerosis Risk in Communities (ARIC) Study (baseline, 1990-1992). We used Poisson regression to characterize the associations between 1,5-AG and prevalent elevated hs-cTnT, thick CIMT, or carotid plaque. Among 9,145 people with a second hs-cTnT measurement 6 years later, we used multinomial logistic regression to assess associations with incident elevation in hs-cTnT.

RESULTS

We found that in people with diabetes, lower 1,5-AG (<6 μg/mL) was cross-sectionally associated with elevated hs-cTnT (prevalence ratio 2.06, 95% CI 1.23-3.46) compared with higher 1,5-AG (≥10 μg/mL). Associations in people without diabetes and with thick CIMT or the presence of carotid plaque were less robust. Low 1,5-AG was prospectively associated with the 6-year incident elevation in hs-cTnT (relative risk 2.90, 95% CI 1.23-6.85) in people with diabetes. All associations were strongly attenuated with further adjustment for HbA1c.

CONCLUSIONS

In people with diabetes, 1,5-AG was associated with subclinical cardiovascular disease, particularly chronic subclinical myocardial damage. Nonetheless, whether observed associations are truly independent of average glycemia is unclear.

Impact of serum 1,5-anhydro-d-glucitol level on prediction of major adverse cardiac and cerebrovascular events in non-diabetic patients without coronary artery disease

BACKGROUND AND AIMS

Increasing evidence has demonstrated that postprandial hyperglycemia and fluctuation of glucose level affect cardiovascular events. The serum 1,5-anhydro-d-glucitol (1,5-AG) level rapidly decreases concomitantly with urinary glucose excretion in hyperglycemia and is a useful clinical marker of short-term glycemic status. However, there is few established evidence regarding the predictive value of 1,5-AG for cardiovascular events in individuals without diabetes mellitus (DM). The aim of this study is 1) to prove predictive value of 1,5-AG for cardiovascular events in high risk population, and 2) the predictive value is true of even in non-diabetic population.

METHODS

Serum 1,5-AG values and coronary angiograms of 889 patients were evaluated. The study patients were divided into two groups (1,5-AG<10.0 μg/ml-group and 1,5-AG≥10.0 μg/ml-group) by their measured 1,5-AG values. They were followed-up and information regarding major adverse cardiac and cerebrovascular events (MACCE) was collected. MACCE consists of all causes of death, stroke, non-fatal myocardial infarction and cardiovascular hospitalization.

RESULTS

During the follow-up period (757 ± 357days), 216 patients presented with MACCE. In all patients, the 1,5-AG <10.0 μg/ml -group demonstrated significantly higher risk of MACCE (adjusted hazard ratio 1.63). Even in non-DM patients without coronary artery disease, the 1,5-AG <10.0 μg/m-group showed significantly higher risk of MACCE (adjusted hazard ratio 2.34). Similar results were found even if the events were limited to: all cause death, non-fatal myocardial infarction and stroke (adjusted hazard ratio 4.07) or all cause death (adjusted hazard ratio 3.54).

CONCLUSIONS

Serum 1,5-AG value predicts MACCE even in non-DM patients without coronary artery disease.

Measurement of 1,5-anhydroglucitol in blood and saliva: from non-targeted metabolomics to biochemical assay

Background

Diabetes testing using saliva, rather than blood and urine, could facilitate diabetes screening in public spaces. We previously identified 1,5-anhydro-d-glucitol (1,5-AG) in saliva as a diabetes biomarker. The Glycomark™ assay kit is FDA approved for 1,5-AG measurement in blood. Here we evaluated its applicability for 1,5-AG quantification in saliva.

Methods

Using pooled saliva samples, we validated Glycomark™ assay use with a RX Daytona⁺ clinical chemistry analyser. We then used this set-up to analyse 82 paired blood and saliva samples from a diabetes case–control study, for which broad mass spectrometry-based characterization of the blood and saliva metabolome was also available. Osmolality was measured to account for potential variability in saliva samples.

Results

The technical variability of the read-outs for the pooled saliva samples (CV = 2.05 %) was comparable to that obtained with manufacturer-provided blood surrogate quality controls (CV = 1.38–1.8 %). We found a high correlation between Glycomark assay and mass spectrometry measurements of serum 1,5-AG (r² = 0.902), showing reproducibility of the non-targeted metabolomics results. The significant correlation between the osmolality measurements performed at two independent platforms with the time interval of 2 years (r² = 0.887), also indicates the sample integrity. The assay read-out for saliva was not correlated with the mass spectrometry-based 1,5-AG saliva measurements. Comparison with the full saliva metabolome revealed a high correlation of the saliva assay read-outs with galactose.

Conclusions

Glycomark™ assay read-outs for saliva were stable and replicable. However, the signal was dominated by galactose, which is biochemically similar to 1,5-AG and absent in blood. Adapting the 1,5-AG kit for saliva analysis will require enzymatic depletion of galactose. This should be feasible, since the assay already includes a similar step for glucose depletion from blood samples.