Serum 1,5-anhydroglucitol when used with fasting plasma glucose improves the efficiency of diabetes screening in a Chinese population

Clinical utility of glycated albumin and 1,5-anhydroglucitol in the screening and prediction of diabetes: A multi-center study

BACKGROUND

Despite being the gold standard, the use of glycated hemoglobin (HbA1c) and fasting plasma glucose (FPG) for diagnosing dysglycemia is imperfect. In particular, a low level of agreement between HbA1c and FPG in detecting prediabetes and diabetes has led to difficulties in clinical interpretation. Glycated albumin (GA) and 1,5-anhydroglucitol (1,5-AG) may potentially serve as biomarkers for the detection and prediction of diabetes, as well as glycemic monitoring.

AIM

To explore the diagnostic performance of GA and 1,5-AG for screening dysglycemia; assess whether they can be used for glycemic monitoring in Chinese morbidly-obese patients; and examine their predictive ability for incident diabetes in a Chinese community-based cohort.

METHODS

GA and 1,5-AG concentrations were measured in 462 morbidly-obese patients from the Obese Chinese Cohort (OCC). A sub-group of diabetes subjects (n = 24) was prospectively followed-up after bariatric surgery. Differences between baseline and post-surgery biomarker values were converted to percentage change from baseline to assess the response to glycemic control. Predictive ability of the biomarkers was assessed in 132 incident diabetes cases and 132 matched non-diabetes controls in the community-based Cardiovascular Risk Factor Prevalence Study (CRISPS). A prediction model was developed and compared with clinical models based on conventional risk factors.

RESULTS

GA exhibited an excellent diagnostic value with an area under the receiver operating characteristic curve (AUC) of 0.919 (95%CI: 0.884-0.955) for identifying diabetes and a high agreement in the classification of diabetes with both FPG and HbA1c in the OCC. GA demonstrated the fastest response to glycemic control. In CRISPS, the 'B3A' prediction model, which consisted of body mass index (BMI) and 3 biomarkers (HbA1c, GA and 1,5-AG), achieved a comparable predictive value [AUC (95%CI): 0.793 (0.744-0.843)] to that of a clinical model comprising BMI, HbA1c, FPG and 2-hour glucose (2hG) [AUC (95%CI): 0.783 (0.733-0.834); DeLong P value = 0.736]. The 'B3A' was significantly superior to a clinical model including BMI, HbA1c, FPG and triglycerides [AUC (95%CI): 0.729 (0.673-0.784); DeLong P value = 0.027].

CONCLUSION

GA and 1,5-AG have the potential to act as robust biomarkers for the screening and risk prediction of diabetes. FPG and 2hG may be replaced by GA and 1,5-AG in future diabetes predictions.

Emerging biomarkers in type 2 diabetes mellitus

Diabetes mellitus is a chronic condition caused by high blood glucose resulting from insufficient insulin production or cellular resistance to insulin action or both. It is one of the fastest-growing public health concerns worldwide. Development of long-term nephropathy, retinopathy, neuropathy, and cardiovascular disease are some of the complications commonly associated with poor blood glycemic control. Type 2 diabetes mellitus (T2DM), the most prevalent type of diabetes, accounts for around 95 % of all cases globally. Although middle-aged or older adults are more likely to develop T2DM, its prevalence has grown in children and young people due to increased obesity, sedentary lifestyle and poor nutrition. Furthermore, it is believed that more than 50 % of cases go undiagnosed annually. Routine screening is essential to ensure early detection and reduce risk of life-threatening complications. Herein, we review traditional biomarkers and highlight the ongoing pursuit of novel and efficacious biomarkers driven by the objective of achieving early, precise and prompt diagnoses. It is widely acknowledged that individual biomarkers will inevitably have certain limitations necessitating the need for integrating multiple markers in screening.

Reference Interval for Glycated Albumin, 1,5-AG/GA, and GA/HbA1c Ratios and Cut-Off Values for Type 1, Type 2, and Gestational Diabetes: A Cross-Sectional Study

Background/Objectives: Glycated albumin (GA) serves as a biomarker for short-term glycemic control (2-3 weeks), playing a role in diabetes management. Our goal was to establish reference intervals (RIs) for serum GA, and the ratios of 1,5-anhydroglucitol to GA (AGI) and GA to HbA1c in a Euro-Brazilian pediatric population (10 y, n = 299), adults (43.5 y; n = 290), and pregnant women (26 y, n = 406; 26.5 ± 3.1 gestation weeks). Methods: Receiver operating characteristic curve analysis was employed to determine RIs for type 1 diabetes (T1D) in children (n = 148) and adults (n = 81), type 2 diabetes (T2D, n = 283), and gestational diabetes mellitus (GDM, n = 177). Results: Both non-pregnant and pregnant women exhibited GA RIs of 10.0-13.3% and 10.6-14.7%, respectively. The AGI ratio varied from 1.2-4.3 in children, 0.9-3.6 in adults, and 0.8-3.1 in pregnant women. Meanwhile, the GA/HbA1c ratio ranged from 1.8-2.6 in children and adults to 2.3-3.6 in pregnant women. GA and AGI ratios accurately differentiated between T1D and T2D, demonstrating high sensitivity (>84%) and specificity (>97%), with AGI showing superior performance (AUC > 0.99). The GA/HbA1c ratio exhibited moderate discriminatory power (AUC > 0.733) but was less effective in distinguishing adult-onset T1D and T2D, suggesting its limited utility in certain groups. Conclusions: The proposed RIs are consistent with those of other Caucasian populations, affirming their relevance for Euro-Brazilian patients. The GA and AGI ratios emerge as valuable diagnostic tools for T1D and T2D, though their reduced sensitivity in diagnosing GDM warrants further investigation. Clinicians might leverage GA and AGI ratios for more tailored diabetes management, especially when HbA1c results are not optimal.

The clinical potential of 1,5-anhydroglucitol as biomarker in diabetes mellitus

A crucial measure of diabetes management is to monitor blood glucose, which often requires continuous blood collection, leading to economic burden and discomfort. Blood glucose and glycated hemoglobin A1c serve as traditional indicators of glucose monitoring. But now glycated albumin, fructosamine, and 1,5-anhydroglucitol (1,5-AG) have been gaining more attention. 1,5-AG is a chemically stable monosaccharide that exists in the human body. Its serum concentration remains stable when blood glucose levels are normal. However, it decreases when blood glucose exceeds the renal glucose threshold. Studies have shown that 1.5-AG reflects blood glucose changes in 1 to 2 weeks; therefore, decreased levels of serum 1,5-AG can serve as a clinical indicator of short-term blood glucose disturbances. Recent studies have shown that 1,5-AG can be used not only for the screening and managing of diabetes but also for predicting diabetes-related adverse events and islet β cell function in prediabetic patients. In addition, saliva 1,5-AG demonstrates potential value in the screening and diagnosis of diabetes. This review focuses on the biological characteristics, detection methods, and clinical application of 1,5-AG to promote understanding and applicable research of 1,5-AG in the future.

Comorbidities confound metabolomics studies of human disease

The co-occurrence of multiple chronic conditions, termed multimorbidity, presents an expanding global health challenge, demanding effective diagnostics and treatment strategies. Chronic ailments such as obesity, diabetes, and cardiovascular diseases have been linked to metabolites interacting between the host and microbiota. In this study, we investigated the impact of co-existing conditions on risk estimations for 1375 plasma metabolites in 919 individuals from population-based Estonian Biobank cohort using liquid chromatography mass spectrometry (LC-MS) method. We leveraged annually linked national electronic health records (EHRs) data to delineate comorbidities in incident cases and controls for the 14 common chronic conditions. Among the 254 associations observed across 13 chronic conditions, we primarily identified disease-specific risk factors (92%, 217/235), with most predictors (93%, 219/235) found to be related to the gut microbiome upon cross-referencing recent literature data. Accounting for comorbidities led to a reduction of common metabolite predictors across various conditions. In conclusion, our study underscores the potential of utilizing biobank-linked retrospective and prospective EHRs for the disease-specific profiling of diverse multifactorial chronic conditions.

Cutoff Values for Glycated Albumin, 1,5-Anhydroglucitol, and Fructosamine as Alternative Markers for Hyperglycemia

BACKGROUND

Glycated albumin (GA), 1,5-anhydroglucitol (1,5-AG), and fructosamine have attracted considerable interest as markers of hyperglycemia. This study aimed to evaluate the optimal cutoff values for GA, 1,5-AG, and fructosamine and to determine their respective diagnostic efficacies in relation to hyperglycemia.

METHODS

We enrolled 6012 individuals who had undergone fasting blood glucose (FBG) and Hemoglobin A1c (HbA1c) tests along with at least one alternative glycemic marker. Receiver operating characteristic (ROC) curves and the upper or lower limit of the reference range (97.5 or 2.5 percentiles) were used to ascertain the optimal cutoff values. Follow-up data from healthy individuals were used to identify patients who developed diabetes mellitus (DM).

RESULTS

The ROC cutoff values for GA, 1,5-AG, and fructosamine were 13.9%, 13.3 μg/mL, and 278 μmol/L, respectively, with corresponding area under the curve (AUC) values of 0.860, 0.879, and 0.834. The upper limits of the reference intervals for GA and fructosamine were 15.1% and 279 μmol/L, respectively, and the lower limit for 1,5-AG was 5.3 μg/mL. Among the GA cutoff values, the ROC cutoff had the highest sensitivity. Analyzing the follow-up data showed that lowering the GA cutoff from 16.0% to 13.9% identified an additional 40 people with DM progression.

CONCLUSIONS

Lowering the GA cutoff values significantly increased the sensitivity of DM diagnosis and enhanced its potential as a screening marker by identifying more individuals with diabetes progression. Conversely, modifications to the cutoff values for 1,5-AG and fructosamine did not confer any discernible diagnostic or predictive advantages.

Advanced Mass Spectrometry-Based Biomarker Identification for Metabolomics of Diabetes Mellitus and Its Complications

Over the years, there has been notable progress in understanding the pathogenesis and treatment modalities of diabetes and its complications, including the application of metabolomics in the study of diabetes, capturing attention from researchers worldwide. Advanced mass spectrometry, including gas chromatography-tandem mass spectrometry (GC-MS/MS), liquid chromatography-tandem mass spectrometry (LC-MS/MS), and ultra-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOF-MS), etc., has significantly broadened the spectrum of detectable metabolites, even at lower concentrations. Advanced mass spectrometry has emerged as a powerful tool in diabetes research, particularly in the context of metabolomics. By leveraging the precision and sensitivity of advanced mass spectrometry techniques, researchers have unlocked a wealth of information within the metabolome. This technology has enabled the identification and quantification of potential biomarkers associated with diabetes and its complications, providing new ideas and methods for clinical diagnostics and metabolic studies. Moreover, it offers a less invasive, or even non-invasive, means of tracking disease progression, evaluating treatment efficacy, and understanding the underlying metabolic alterations in diabetes. This paper summarizes advanced mass spectrometry for the application of metabolomics in diabetes mellitus, gestational diabetes mellitus, diabetic peripheral neuropathy, diabetic retinopathy, diabetic nephropathy, diabetic encephalopathy, diabetic cardiomyopathy, and diabetic foot ulcers and organizes some of the potential biomarkers of the different complications with the aim of providing ideas and methods for subsequent in-depth metabolic research and searching for new ways of treating the disease.

Liquid Biopsy: A Game Changer for Type 2 Diabetes

As the burden of type 2 diabetes (T2D) continues to escalate globally, there is a growing need for novel, less-invasive biomarkers capable of early diabetes detection and monitoring of disease progression. Liquid biopsy, recognized for its minimally invasive nature, is increasingly being applied beyond oncology, and nevertheless shows its potential when the collection of the tissue biopsy is not possible. This diagnostic approach involves utilizing liquid biopsy markers such as cell-free nucleic acids, extracellular vesicles, and diverse metabolites for the molecular diagnosis of T2D and its related complications. In this context, we thoroughly examine recent developments in T2D liquid biopsy research. Additionally, we discuss the primary challenges and future prospects of employing liquid biopsy in the management of T2D. Prognosis, diagnosis and monitoring of T2D through liquid biopsy could be a game-changing technique for personalized diabetes management.

SGLT5 is the renal transporter for 1,5-anhydroglucitol, a major player in two rare forms of neutropenia

Neutropenia and neutrophil dysfunction in glycogen storage disease type 1b (GSD1b) and severe congenital neutropenia type 4 (SCN4), associated with deficiencies of the glucose-6-phosphate transporter (G6PT/SLC37A4) and the phosphatase G6PC3, respectively, are the result of the accumulation of 1,5-anhydroglucitol-6-phosphate in neutrophils. This is an inhibitor of hexokinase made from 1,5-anhydroglucitol (1,5-AG), an abundant polyol in blood. 1,5-AG is presumed to be reabsorbed in the kidney by a sodium-dependent-transporter of uncertain identity, possibly SGLT4/SLC5A9 or SGLT5/SLC5A10. Lowering blood 1,5-AG with an SGLT2-inhibitor greatly improved neutrophil counts and function in G6PC3-deficient and GSD1b patients. Yet, this effect is most likely mediated indirectly, through the inhibition of the renal 1,5-AG transporter by glucose, when its concentration rises in the renal tubule following inhibition of SGLT2. To identify the 1,5-AG transporter, both human and mouse SGLT4 and SGLT5 were expressed in HEK293T cells and transport measurements were performed with radiolabelled compounds. We found that SGLT5 is a better carrier for 1,5-AG than for mannose, while the opposite is true for human SGLT4. Heterozygous variants in SGLT5, associated with a low level of blood 1,5-AG in humans cause a 50-100% reduction in 1,5-AG transport activity tested in model cell lines, indicating that SGLT5 is the predominant kidney 1,5-AG transporter. These and other findings led to the conclusion that (1) SGLT5 is the main renal transporter of 1,5-AG; (2) frequent heterozygous mutations (allelic frequency > 1%) in SGLT5 lower blood 1,5-AG, favourably influencing neutropenia in G6PC3 or G6PT deficiency; (3) the effect of SGLT2-inhibitors on blood 1,5-AG level is largely indirect; (4) specific SGLT5-inhibitors would be more efficient to treat these neutropenias than SGLT2-inhibitors.

Treatment of the Neutropenia Associated with GSD1b and G6PC3 Deficiency with SGLT2 Inhibitors

Glycogen storage disease type Ib (GSD1b) is due to a defect in the glucose-6-phosphate transporter (G6PT) of the endoplasmic reticulum, which is encoded by the SLC37A4 gene. This transporter allows the glucose-6-phosphate that is made in the cytosol to cross the endoplasmic reticulum (ER) membrane and be hydrolyzed by glucose-6-phosphatase (G6PC1), a membrane enzyme whose catalytic site faces the lumen of the ER. Logically, G6PT deficiency causes the same metabolic symptoms (hepatorenal glycogenosis, lactic acidosis, hypoglycemia) as deficiency in G6PC1 (GSD1a). Unlike GSD1a, GSD1b is accompanied by low neutrophil counts and impaired neutrophil function, which is also observed, independently of any metabolic problem, in G6PC3 deficiency. Neutrophil dysfunction is, in both diseases, due to the accumulation of 1,5-anhydroglucitol-6-phosphate (1,5-AG6P), a potent inhibitor of hexokinases, which is slowly formed in the cells from 1,5-anhydroglucitol (1,5-AG), a glucose analog that is normally present in blood. Healthy neutrophils prevent the accumulation of 1,5-AG6P due to its hydrolysis by G6PC3 following transport into the ER by G6PT. An understanding of this mechanism has led to a treatment aimed at lowering the concentration of 1,5-AG in blood by treating patients with inhibitors of SGLT2, which inhibits renal glucose reabsorption. The enhanced urinary excretion of glucose inhibits the 1,5-AG transporter, SGLT5, causing a substantial decrease in the concentration of this polyol in blood, an increase in neutrophil counts and function and a remarkable improvement in neutropenia-associated clinical signs and symptoms.

Circulating 1,5-Anhydroglucitol as a Biomarker of ß-cell Mass Independent of a Diabetes Phenotype in Human Subjects

CONTEXT

During an asymptomatic prediabetic state, the functional ß-cell mass decreases to a critical threshold, triggering diabetes and related symptoms. To date, there are no reliable readouts able to capture in vivo a potential drop of the ß-cell mass.

OBJECTIVE

Beside its use as a short-term marker of glycemic control, the deoxyhexose 1,5-anhydroglucitol was identified in rodents as a circulating biomarker of the functional ß-cell mass already in the asymptomatic prediabetic stage. The present study investigated the putative corresponding relevance of circulating 1,5-anhydroglucitol in different human cohorts.

METHODS

We analyzed clinical and blood parameters in patients with established type 2 diabetes and subjects considered at high risk of developing diabetes, as well as patients with no history of diabetes scheduled for pancreaticoduodenectomy.

RESULTS

Circulating 1,5-anhydroglucitol was reduced in type 2 diabetic patients, negatively correlating with fasting plasma glucose (P < 0.0001) and hemoglobin A1c (P < 0.0001). In healthy subjects, 1,5-AG levels positively correlated with body mass index (P = 0.004) and Homeostatic Model Assessment of Insulin Resistance %S (P < 0.03) and was particularly high in nondiabetic obese individuals, potentially accounting for compensatory ß-cell expansion. Patients with no history of diabetes undergoing pancreaticoduodenectomy exhibited a 50% reduction of circulating 1,5-anhydroglucitol levels following surgery leading to an acute loss of their ß-cell mass (P = 0.002), regardless their glucose tolerance status.

CONCLUSION

In summary, plasma concentration of 1,5-anhydroglucitol follows the ß-cell mass and its noninvasive monitoring may alert about the loss of ß cells in subjects at risk for diabetes, an event that cannot be captured by other clinical parameters of glycemic control.

Successful use of empagliflozin to treat neutropenia in two G6PC3-deficient children: Impact of a mutation in SGLT5

Neutropenia and neutrophil dysfunction found in deficiencies in G6PC3 and in the glucose-6-phosphate transporter (G6PT/SLC37A4) are due to accumulation of 1,5-anhydroglucitol-6-phosphate (1,5-AG6P), an inhibitor of hexokinase made from 1,5-anhydroglucitol (1,5-AG), an abundant polyol present in blood. Lowering blood 1,5-AG with an SGLT2 inhibitor greatly improved neutrophil counts and function in G6PC3-deficient mice and in patients with G6PT-deficiency. We evaluate this treatment in two G6PC3-deficient children. While neutropenia was severe in one child (PT1), which was dependent on granulocyte cololony-stimulating factor (GCSF), it was significantly milder in the other one (PT2), which had low blood 1,5-AG levels and only required GCSF during severe infections. Treatment with the SGLT2-inhibitor empagliflozin decreased 1,5-AG in blood and 1,5-AG6P in neutrophils and improved (PT1) or normalized (PT2) neutrophil counts, allowing to stop GCSF. On empagliflozin, both children remained infection-free (>1 year - PT2; >2 years - PT1) and no side effects were reported. Remarkably, sequencing of SGLT5, the gene encoding the putative renal transporter for 1,5-AG, disclosed a rare heterozygous missense mutation in PT2, replacing the extremely conserved Arg401 by a histidine. The higher urinary clearance of 1,5-AG explains the more benign neutropenia and the outstanding response to empagliflozin treatment found in this child. Our data shows that SGLT2 inhibitors are an excellent alternative to treat the neutropenia present in G6PC3-deficiency.

HbA1c combined with glycated albumin or 1,5-anhydroglucitol improves the efficiency of diabetes screening in a Chinese population

AIMS

This study aimed to evaluate the ability of HbA_1c combined with glycated albumin (GA) or 1,5-anhydroglucitol (1,5-AG) to detect diabetes in residents of Jiangsu, China.

METHODS

The oral glucose tolerance test (OGTT) was performed on 2184 people in Jiangsu. HbA_1c , GA, 1,5-AG and other serum biochemical parameters were measured. Receiver operating characteristic curves were plotted to determine the optimal thresholds of HbA_1c , GA and 1,5-AG according to the Youden index.

RESULTS

(1) The optimal thresholds of HbA_1c , GA and 1,5-AG for the screening of diabetes were ≥45 mmol/mol (6.3%), ≥13.0% and ≤23.0 μg/ml, respectively. (2) The sensitivities of HbA_1c combined with GA and 1,5-AG were both 85%, higher than that of HbA_1c (70%, p < 0.001).

CONCLUSIONS

This study is suitable for cases where plasma glucose is unavailable. Among the residents of Jiangsu, HbA_1c combined with GA or 1,5-AG can improve the sensitivity of diabetes screening, reduce the miss rate and save the use of OGTT. GA and 1,5-AG are superior in individuals with mild glucose metabolism disorder. GA enhances the detection of diabetes in the nonobese, and 1,5-AG enhances the detection in those with hyperuricaemia.

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.

Saliva 1,5-anhydroglucitol is associated with early-phase insulin secretion in Chinese patients with type 2 diabetes

INTRODUCTION

Saliva collection is a non-invasive test and is convenient. 1,5-anhydroglucitol (1,5-AG) is a new indicator reflecting short-term blood glucose levels. This study aimed to explore the relationship between saliva 1,5-AG and insulin secretion function and insulin sensitivity.

RESEARCH DESIGN AND METHODS

Adult patients with type 2 diabetes who were hospitalized were enrolled. Based on blood glucose and C-peptide, homeostasis model assessment 2 for β cell secretion function, C-peptidogenic index (CGI), △2-hour C-peptide (2hCP)/△2-hour postprandial glucose (2hPG), ratio of 0-30 min area under the curve for C-peptide and area under the curve for glucose (AUC_CP30/AUC_PG30), and AUC_2hCP/AUC_2hPG were calculated to evaluate insulin secretion function, while indicators such as homeostasis model assessment 2 for insulin resistance were used to assess insulin sensitivity.

RESULTS

We included 284 subjects (178 men and 106 women) with type 2 diabetes aged 20-70 years. The saliva 1,5-AG level was 0.133 (0.089-0.204) µg/mL. Spearman's correlation analysis revealed a significantly negative correlation between saliva 1,5-AG and 0, 30, and 120 min blood glucose, glycated hemoglobin A_1c, and glycated albumin (all p<0.05), and a significantly positive association between saliva 1,5-AG and CGI (r=0.171, p=0.004) and AUC _CP30 /AUC _PG30 (r=0.174, p=0.003). The above correlations still existed after adjusting for age, sex, body mass index, and diabetes duration. In multiple linear regression, saliva 1,5-AG was an independent factor of CGI (standardized β=0.135, p=0.015) and AUC _CP30 /AUC _PG30 (standardized β=0.110, p=0.020).

CONCLUSIONS

Saliva 1,5-AG was related to CGI and AUC_CP30/AUC_PG30 in patients with type 2 diabetes.

TRIAL REGISTRATION NUMBER

ChiCTR-SOC-17011356.

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.

Reference intervals for serum 1,5-anhydroglucitol of a population with normal glucose tolerance in Jiangsu Province

BACKGROUND

Serum 1,5-anhydroglucitol (1,5-AG) is a new glycemic marker which can reflect glucose fluctuation over 3 to 7 days and is now increasingly used to monitor glucose control and to screen for diabetes. However, 1,5-AG has not been widely used in China due to lack of epidemiological support. Our study aims to establish the reference intervals for a population with normal glucose tolerance in Jiangsu Province and to explore the determinants of these intervals.

METHOD

The study enrolled 646 healthy adults aged 20 to 70 years in Jiangsu Province in 2018 after oral glucose tolerance test. 1,5-AG, fasting and 2-hour glucose, UA, liver enzyme, serum lipid, creatinine, and glycosylated hemoglobin were measured. We calculated reference intervals using the parametric method and examined the relationship between 1,5-AG and influence factors.

RESULTS

The average age of the participants was 50.5 ± 9.0 years, and 69.5% of them were females. The reference intervals were 15.8 to 52.6 μg/mL for males and 14.3 to 48.0 μg/mL for females. Among females, the reference intervals were 13.9 to 45.3 and 14.6 to 49.6 μg/mL for menopausal and postmenopausal females, respectively. Males showed higher 1,5-AG concentrations than females, and postmenopausal females had higher 1,5-AG than menopausal females. There was a positive correlation between uric acid and 1,5-AG in both genders. Positive correlation between 1,5-AG and age was only observed in females.

CONCLUSION

We established reference intervals for 1,5-AG in Jiangsu Province, and the level of 1,5-AG is affected by sex, uric acid, and age.

Diabetes Screening: Detection and Application of Saliva 1,5-Anhydroglucitol by Liquid Chromatography-Mass Spectrometry

CONTEXT

Unlike other commonly used invasive blood glucose-monitoring methods, saliva detection prevents patients from suffering physical uneasiness. However, there are few studies on saliva 1,5-anhydroglucitol (1,5-AG) in patients with diabetes mellitus (DM).

OBJECTIVE

This study aimed to evaluate the effectiveness of saliva 1,5-AG in diabetes screening in a Chinese population.

DESIGN AND PARTICIPANTS

This was a population-based cross-sectional study. A total of 641 subjects without a valid diabetic history were recruited from September 2018 to June 2019. Saliva 1,5-AG was measured with liquid chromatography-mass spectrometry.

MAIN OUTCOME MEASURES

DM was defined per American Diabetes Association criteria. The efficiency of saliva 1,5-AG for diabetes screening was analyzed by receiver operating characteristic curves, and the optimal cutoff point was determined according to the Youden index.

RESULTS

Saliva 1,5-AG levels in subjects with DM were lower than those in subjects who did not have DM (both P < .05). Saliva 1,5-AG was positively correlated with serum 1,5-AG and negatively correlated with blood glucose and glycated hemoglobin (HbA1c) (all P < .05). The optimal cutoff points of saliva 1,5-AG0 and 1,5-AG120 for diabetes screening were 0.436 μg/mL (sensitivity: 63.58%, specificity: 60.61%) and 0.438 μg/mL (sensitivity: 62.25%, specificity: 60.41%), respectively. Fasting plasma glucose (FPG) combined with fasting saliva 1,5-AG reduced the proportion of people who required an oral glucose tolerance test by 47.22% compared with FPG alone.

CONCLUSION

Saliva 1,5-AG combined with FPG or HbA1c improved the efficiency of diabetes screening. Saliva 1,5-AG is robust in nonfasting measurements and a noninvasive and convenient tool for diabetes screening.

1,5-Anhydroglucitol × glycated hemoglobin A1c/100 as a potential biomarker for islet β-cell function among patients with type 2 diabetes

AIMS

This study aimed to explore the level of and changes in the 1,5-anhydroglucitol × glycated hemoglobin A_1c/100 (AH index, AHI) associated with different glucose metabolism statuses and to evaluate the islet function and insulin sensitivity of patients with type 2 diabetes (T2DM) with different AHI levels.

METHODS

Of the 3562 subjects enrolled in this study, 1697 had T2DM. The disposition index (DI) was the product of islet secretion function and insulin sensitivity-related indexes.

RESULTS

The mean AHI level was 1.0 (0.7-1.3) in the general population, while the mean AHI level in the T2DM group was 0.8 (0.5-1.2), which was significantly lower than that in the impaired glucose regulation and normal glucose tolerance group (both 1.2 (0.9-1.5), both P < 0.01). We further divided patients with T2DM into four subgroups according to the quartile of AHI. The results showed that with the increase in AHI level, the homeostasis model assessment of insulin resistance (HOMA-IR) decreased, while HOMA-β, insulin generation index, insulin sensitivity index, and DI increased (all P_{for trend} < 0.01). Multivariate logistic regression showed that the odds ratios for a low DI for increasing levels of AHI were 1.00, 0.22 (0.16-0.29), 0.16 (0.11-0.22), and 0.09 (0.06-0.13), showing a decreasing trend (P_{for trend} < 0.05).

CONCLUSION

The AHI could reflect the variation in glycemic disorder and the function of islet β cells. The lower the AHI, the worse the glycemic disorder, as well as the islet β-cell function.

Serum 1,5-Anhydroglucitol to Glycated Albumin Ratio Can Help Early Distinguish Fulminant Type 1 Diabetes Mellitus from Newly Onset Type 1A Diabetes Mellitus

BACKGROUND

Fulminant type 1 diabetes mellitus (FT1DM) onsets abruptly and usually occurs within 1 week after the onset of hyperglycemic symptoms. Glycated albumin (GA) and 1,5-anhydroglucitol (1,5-AG) are indicators that reflect short-term glucose levels. This study was aimed at investigating whether the 1,5-AG/GA index (AGI) is a suitable indicator for early FT1DM identification.

METHODS

A total of 226 subjects were enrolled, all with glycated hemoglobin A1c (HbA1c) < 8.7%. FT1DM was diagnosed based on the 2012 Japan Diabetes Society criteria.

RESULTS

The AGI level was 0.54 (0.17-1.36) in the whole group. It was lower in FT1DM patients (0.16 [0.10-0.25]). Among the participants whose HbA1c did not exceed 7.0%, the AGI of FT1DM decreased significantly compared to type 1A diabetes (T1ADM) and latent autoimmune diabetes in adults (LADA) patients (0.16 [0.12-0.26] vs. 0.46 [0.24-0.72] vs. 0.46 [0.24-0.72] P < 0.05). The receiver operating characteristic (ROC) curve showed that AGI can be used to distinguish FT1DM and T1ADM patients with HbA1c < 8.7%. Diagnosing FT1DM based on AGI ≤ 0.3 only can help narrow down suspected FT1DM by up to 26.87%. If we diagnosed FT1DM when AGI was ≤0.3 and HbA1c was ≤7.0%, the success rate further increased to 86.57%, among which 85.00% of FT1DM and 87.23% of T1ADM patients were successfully identified. Therefore, using the combination criteria of AGI and HbA1c would improve the differential diagnosis efficacy by 61.11% compared with the AGI criterion only.

CONCLUSION

AGI can help facilitate the early differential diagnosis of FT1DM and T1ADM when HbA1c < 8.7%, with an optimal cut-off point of 0.3.

Enhancement of Fenton processes at initial circumneutral pH for the degradation of norfloxacin with Fe@Fe2O3 core-shell nanomaterials

The degradation of norfloxacin by Fenton reagent with core-shell Fe@Fe₂O₃ nanomaterials was studied under neutral conditions in a closed batch system. Norfloxacin was significantly degraded (90%) in the Fenton system with Fe@Fe₂O₃ in 30 min at the initial pH 7.0, but slightly degraded in Fenton system without Fe@Fe₂O₃ under the same experimental conditions. The intermediate products were investigated by gas chromatography-mass spectrometry, and the possible Fenton oxidation pathway of norfloxacin in the presence of Fe@Fe₂O₃ nanowires was proposed. Electron spin resonance spectroscopy was used to identify and characterize the free radicals generated, and the mechanism for norfloxacin degradation was also revealed. Finally, the reusability and the stability of Fe@Fe₂O₃ nanomaterials were studied using x-ray diffraction and scanning electron microscope, which indicated that Fe@Fe₂O₃ is a stable catalyst and can be used repetitively in environmental pollution control.

The marker of adverse prognosis 1.5-anhydroglucitol in patients with coronary heart disease in the long-term period after planned myocardial revascularization

AIM

Determination of the prognostic value of 1.5-anhydroglucitol (1.5-AG) for the development of cardiovascular events in patients with coronary heart disease (CHD) within a year after a planned percutaneous coronary intervention (PCI).

MATERIALS AND METHODS

A prospective study was conducted in Federal State Budgetary Institution Research Institute for Complex Issues of Cardiovascular Disease among 149 patients admitted to planned PCI in the period from 2016 to 2017. Criteria for inclusion in the study: age up to 70 years, angina I-IV functional classes or post-infarction cardiosclerosis, the presence of indications for planned PCI. -Exclusion criteria from the study: previous myocardial revascularization; prosthetic heart valves; decompensation of chronic heart failure, anemia of any degree; acute coronary syndrome in index hospitalization; exacerbation of somatic diseases. The results of the research were processed by Statistica Windows 6.0.

RESULTS

During the year after planned PCI, 39 (26.14%) cardiovascular events were registered in patients with CHD, of whom more than half of the cases (51.28%) were associated with the presence of indications for PCI of de novo. Lower levels of 1.5-AG were observed in the group of patients with cardiovascular events (p=0.000). When patients were divided according to median of the studied marker patients with a concentration of 1.5-AG less 20.96 μg/ml (before PCI) were more likely to have PCI after restenosis of the stent, compared with patients whose median concentration of this marker was higher (p=0.028). The logistic regression method revealed a significant direct relationship reflecting the prognostic value of lower concentration of 1.5-AG in relation to the development of cardiovascular events in patients regardless of the presence of carbohydrate metabolism disorders [OR 0.25 (0.10-0.62)].

CONCLUSION

According to the results of the study, the prognostic value of the concentration of 1.5-AG less 20.96 µg/ml was established in relation to the development of cardiovascular events in patients with CHD during the year after a planned PCI, regardless of the presence of carbohydrate metabolism disorders.

The metabolism and transport of 1,5-anhydroglucitol in cells

AIMS

Our previous studies demonstrated that serum 1,5-anhydroglucitol (1,5-AG) levels increased slightly rather than declined after an acute glucose load. Therefore, the current study aims at exploring the transport and metabolic characteristics of 1,5-AG, as well as the effect of glucose on 1,5-AG transport.

METHODS

K_m and V_max were determined to measure the affinity of glucose oxidase (GOD) and hexokinase (HK) for 1,5-AG and glucose. HepG2, C2C12, and primary mouse hepatocytes were incubated for 2 h with 1,5-AG at concentrations of 0, 80, and 160 μg/mL. Then, intracellular and extracellular concentrations of 1,5-AG were measured before and after washing with PBS to evaluate the transport and metabolic rates of 1,5-AG. In addition, the influence of an acute glucose load on the transport of 1,5-AG was studied.

RESULTS

The affinity of GOD and HK for 1,5-AG is 5 and 42.5% of that for glucose, respectively. Moreover, there is no de novo synthesis of 1,5-AG, and its metabolic rate is < 3%. After a 2 h incubation with additional 1,5-AG, the intracellular levels of 1,5-AG were 50-80% of extracellular levels. Moreover, intracellular 1,5-AG concentrations decreased rapidly and reached zero following the removal of 1,5-AG from the external medium. In addition, an acute glucose load can affect the dynamic balance of 1,5-AG, causing the intracellular 1,5-AG levels to decline significantly and the extracellular levels to increase slightly in HepG2 cells.

CONCLUSIONS

Unlike glucose, 1,5-AG is hard to be metabolized in vivo, and its transport is influenced by an acute glucose load in hepatocytes.