Effect of renal function on serum concentration of 1,5-anhydroglucitol in type 2 diabetic patients in chronic kidney disease stages I-III: A comparative study with HbA1c and glycated albumin

BACKGROUND

1,5-Anhydroglucitol (1,5-AG) is a new blood glucose control marker reflecting temporary glucose elevations. However, 1,5-AG is of limited value in patients with advanced renal insufficiency. The aim of the present study was to assess the correlation between 1,5-AG levels and renal function in patients with earlier stages of nephropathy compared with another two markers of diabetes control, namely HbA1c and glycated albumin (GA).

METHODS

The following parameters were measured in 377 patients with type 2 diabetes: HbA1c, serum concentrations of 1,5-AG, GA and creatinine, hemoglobin, urinary albumin/creatinine ratio, and urinary excretion of α1 -microglobulin (A1M). Estimated glomerular filtration rate (eGFR) was calculated according to the Cockgroft-Gault formula.

RESULTS

There was a negative correlation between 1,5-AG and renal function (r = -0.18; P < 0.001). Concentrations of 1,5-AG were, on average, 27.2% lower in patients with glomerular hyperfiltration (eGFR >120 mL/min) compared with patients with moderate renal impairment (eGFR 30-59 mL/min; P = 0.016). In contrast, HbA1c, GA levels and urinary A1M excretion did not differ between the two patient groups. The mean age of patients with eGFR 30-59 mL/min was substantially higher than that of patients with glomerular hyperfiltration (P < 0.001). Thus, an age-related change in the renal glucose threshold could be the reason for the observed correlation between 1,5-AG and renal function.

CONCLUSIONS

In clinical practice, age and renal function must be taken into consideration when interpreting 1,5-AG levels, even in the absence of advanced renal impairment.

Association of 1,5-Anhydroglucitol With Cardiovascular Disease and Mortality

In diabetes, low concentrations of the biomarker 1,5-anhydroglucitol (1,5-AG) reflect hyperglycemic excursions over the prior 1-2 weeks. To the extent that hyperglycemic excursions are important in atherogenesis, 1,5-AG may provide independent information regarding cardiovascular risk. Nonetheless, few studies have evaluated associations of 1,5-AG with long-term cardiovascular outcomes in a population-based setting. We measured 1,5-AG in 11,106 participants in the Atherosclerosis Risk in Communities (ARIC) study without cardiovascular disease at baseline (1990-1992) and examined prospective associations with coronary heart disease (n = 1,159 events), ischemic stroke (n = 637), heart failure (n = 1,553), and death (n = 3,120) over 20 years of follow-up. Cox proportional hazards models were adjusted for demographic and cardiovascular risk factors. Compared with persons with 1,5-AG ≥6 μg/mL and no history of diabetes, persons with diabetes and 1,5-AG <6.0 μg/mL had an increased risk of coronary heart disease (HR 3.85, 95% CI 3.11-4.78), stroke (HR 3.48, 95% CI 2.66-4.55), heart failure (HR 3.50, 95% CI 2.93-4.17), and death (HR 2.44, 95% CI 2.11-2.83). There was a threshold effect, with little evidence for associations at "nondiabetic" concentrations of 1,5-AG (e.g., >10 μg/mL). Associations remained but were attenuated with additional adjustment for fasting glucose or HbA1c. These data add to the growing evidence for the prognostic value of 1,5-AG for long-term complications in the setting of diabetes.

Model analysis of effect of canagliflozin (Invokana), a sodium-glucose cotransporter 2 inhibitor, to alter plasma 1,5-anhydroglucitol

BACKGROUND

Renal reabsorption of 1,5-anhydroglucitol (AG) is competitively inhibited by elevated glucose and leads to depleted plasma AG in diabetes. Plasma AG recovery in diabetes normally correlates with improved glycemic control. However, use of sodium-glucose co-transporter 2 (SGLT2) inhibitors (e.g., canagliflozin) to treat diabetes by inhibition of renal glucose reabsorption can negate this correlation, via an indirect effect (increase of renal filtrate glucose concentration) to inhibit AG reabsorption by sodium-glucose co-transporter 4 (SGLT4). Conversely, then, AG measurement might be useful as an independent marker for SGLT2 inhibitor activity.

METHODS

Using an AG mass balance model, we analyzed literature data on plasma AG before and after initiation of canagliflozin therapy (CT) to quantitatively characterize the effect of CT on AG reabsorption.

RESULTS

According to model calculations, modest decreases (<5%) in fractional reabsorption of AG account for the drastic decrease in [AG] observed during CT. Decreases are predicted to be rapid (t1/2<3days) after CT initiation.

CONCLUSION

CT negates the usual premise of AG measurement (that [AG] should increase with improved glycemic control). However, according to model calculations, a substantial and likely rapid effect of CT on [AG] means that AG measurement might provide an early marker for CT activity.

Effect of postprandial hyperglycaemia on coronary flow reserve in patients with impaired glucose tolerance and type 2 diabetes mellitus

BACKGROUND

This study investigated whether postprandial hyperglycaemia has an adverse effect on coronary microvascular function and left ventricular diastolic function.

METHODS

In all, 28 patients with type 2 diabetes mellitus with no significant stenosis in left anterior descending artery were enrolled. In all subjects, plasma 1,5-anhydroglucitol was measured, and coronary flow reserve in the left anterior descending artery was evaluated using a Doppler wire. Membrane type-1 matrix metalloproteinase expression on circulating peripheral blood mononuclear cells was measured by flow cytometry. Correlation analyses were performed for coronary flow reserve and 1,5-anhydroglucitol, other coronary risk factors, membrane type-1 matrix metalloproteinase and E/e'.

RESULTS

Strong correlations were found only between 1,5-anhydroglucitol and coronary flow reserve and membrane type-1 matrix metalloproteinase. On multiple regression analysis, 1,5-anhydroglucitol remained an independent predictor of coronary flow reserve (β = 0.38, p = 0.048).

CONCLUSION

Postprandial hyperglycaemia appears to have an adverse effect on coronary microvascular function, suggesting that improvement of postprandial hyperglycaemia may contribute to the improvement of coronary microvascular dysfunction.

Low levels of C-peptide have clinical significance for established Type 1 diabetes

AIM

To determine whether the low C-peptide levels (< 50 pmol/l) produced by the pancreas for decades after onset of Type 1 diabetes have clinical significance.

METHODS

We evaluated fasting C-peptide levels, duration of disease and age of onset in a large cross-sectional series (n = 1272) of people with Type 1 diabetes. We then expanded the scope of the study to include the relationship between C-peptide and HbA1c control (n = 1273), as well as diabetic complications (n = 324) and presence of hypoglycaemia (n = 323). The full range of C-peptide levels was also compared with 1,5-Anhydroglucitol, a glucose responsive marker.

RESULTS

C-peptide levels declined for decades after diagnosis, and the rate of decline was significantly related to age of onset (P < 0.0001), after adjusting for disease duration. C-peptide levels > 10 pmol/l were associated with protection from complications (e.g. nephropathy, neuropathy, foot ulcers and retinopathy; P = 0.03). Low C-peptide levels were associated with poor metabolic control measured by HbA1c (P < 0.0001). Severe hypoglycaemia was associated with the lowest C-peptide levels compared with mild (P = 0.049) or moderate (P = 0.04) hypoglycaemia. All levels of measurable C-peptide were responsive to acute fluctuations in blood glucose levels as assessed by 1,5-Anhydroglucitol (P < 0.0001).

CONCLUSIONS

Low C-peptide levels have clinical significance and appear helpful in characterizing groups at-risk for faster C-peptide decline, complications, poorer metabolic control and severe hypoglycaemia. Low C-peptide levels may be a biomarker for characterizing at-risk patients with Type 1 diabetes.

Teneligliptin improves left ventricular diastolic function and endothelial function in patients with diabetes

Incretin hormones have been reported to have cytoprotective actions in addition to their glucose-lowering effects. We evaluated whether teneligliptin, a novel dipeptidyl peptidase-4 (DPP-4) inhibitor, affects left ventricular (LV) function in patients with type 2 diabetes mellitus (T2DM). Twenty-nine T2DM patients not receiving any incretin-based drugs were enrolled and prescribed with teneligliptin for 3 months. Compared to baseline levels, hemoglobin A1c levels decreased (7.6 ± 1.0 % to 6.9 ± 0.7 %, p < 0.01) and 1,5-anhydro-D-glucitol levels increased (9.6 ± 7.2 μg/mL to 13.5 ± 8.7 μg/mL, p < 0.01) after treatment. Clinical parameters, including body mass index and blood pressure, did not show any difference before and after treatment. Three months after treatment, there were improvements in LV systolic and diastolic function [LV ejection fraction, 62.0 ± 6.5 % to 64.5 ± 5.0 %, p = 0.01; peak early diastolic velocity/basal septal diastolic velocity (E/e') ratio, 13.3 ± 4.1 to 11.9 ± 3.3, p = 0.01]. Moreover, there was an improvement in endothelial function (reactive hyperemia peripheral arterial tonometry [RH-PAT] index; 1.58 ± 0.47 to 2.01 ± 0.72, p < 0.01). There was a significant negative correlation between changes in the E/e' ratio and RH-PAT values. Furthermore, circulating adiponectin levels increased (27.0 ± 38.5 pg/mL to 42.7 ± 33.2 pg/mL, p < 0.01) without changes in patient body weight. Teneligliptin treatment was associated with improvements in LV function and endothelial functions, and an increase in serum adiponectin levels. These results support the cardio-protective effects of teneligliptin in T2DM patients and increase in serum adiponectin levels.

Chronic Dietary Administration of the Glycolytic Inhibitor 2-Deoxy-D-Glucose (2-DG) Inhibits the Growth of Implanted Ehrlich's Ascites Tumor in Mice

Background

Dietary energy restriction (DER) has been well established as a potent anticancer strategy. Non-adoption of restricted diet for an extended period has limited its practical implementation in humans with a compelling need to develop agents that mimic effects similar to DER, without reduction in actual dietary intake. Glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), has recently been shown to possess potential as an energy restriction mimetic agent (ERMA). In the present study we evaluated the effect of dietary 2-DG administration on a mouse tumor model, with a focus on several potential mechanisms that may account for the inhibition of tumorigenesis.

Methodology/Principal Findings

Swiss albino strain ‘A’ mice were administered with 0.2% and 0.4% w/v 2-DG in drinking water for 3 months prior to tumor implantation (Ehrlich’s ascites carcinoma; EAC) and continued till the termination of the study with no adverse effects on general physiology and animal growth. Dietary 2-DG significantly reduced the tumor incidence, delayed the onset, and compromised the tumor growth along with enhanced survival. We observed reduced blood glucose and serum insulin levels along with decreased proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine positive (BrdU⁺) tumor cells in 2-DG fed mice. Also, reduced levels of certain key players of metabolic pathways such as phosphatidylinositol 3-kinase (PI3K), phosphorylated-Akt and hypoxia inducible factor-1 alpha (HIF-1α) were also noted in tumors of 2-DG fed mice. Further, decrease in CD4⁺/CD8⁺ ratio and T-regulatory cells observed in 2-DG fed mice suggested enhanced antitumor immunity and T cell effector function.

Conclusion/Significance

These results strongly suggest that dietary 2-DG administration in mice, at doses easily achievable in humans, suitably modulates several pleotrophic factors mimicking DER and inhibits tumorigenesis, emphasizing the use of ERMAs as a promising cancer preventive strategy.

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

BACKGROUND

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

SUBJECTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Add-on treatment with teneligliptin ameliorates glucose fluctuations and improves glycemic control index in Japanese patients with type 2 diabetes on insulin therapy

BACKGROUND

This study investigated whether teneligliptin, a novel dipeptidyl peptidase-4 inhibitor, ameliorated glucose fluctuations in hospitalized Japanese patients with type 2 diabetes receiving insulin therapy, with or without other antidiabetes drugs, and using continuous glucose monitoring (CGM).

PATIENTS AND METHODS

Twenty-six patients with type 2 diabetes were admitted for glycemic control. After admission, patients continued to be treated with optimal dietary therapy plus insulin therapy, with or without other antidiabetes drugs, until they achieved stable glycemic control. CGM measurements were made for 7 consecutive days. On Days 1-3, patients received insulin with or without other antidiabetes drugs, and on Days 4-7, teneligliptin 20 mg once daily at breakfast was added to ongoing therapy. Doses of insulin were fixed during the study. Levels of serum glycated albumin (GA), 1,5-anhydro-d-glucitol (1,5-AG), and high-sensitivity C-reactive protein (hsCRP) were measured.

RESULTS

Add-on treatment with teneligliptin led to significant improvements in 24-h mean glucose levels, the proportion of time in normoglycemia, mean amplitude of glycemic excursions, and total area under the curve within 2 h after each meal. The proportion of time in hypoglycemia and hsCRP levels did not increase significantly compared with before teneligliptin. Values of 1,5-AG and GA were significantly improved by treatment with teneligliptin.

CONCLUSIONS

Addition of teneligliptin to insulin therapy led to a significant improvement in diurnal glycemic control and significant reductions in glucose fluctuations in 24-h periods without increasing hypoglycemia in Japanese patients with type 2 diabetes on insulin therapy, with or without other antidiabetes agents.

Differential mechanisms of radiosensitization by 2-deoxy-D-glucose in the monolayers and multicellular spheroids of a human glioma cell line

In vitro studies using monolayer cultures of human tumor cell lines have shown that 2-DG selectively inhibits energy-dependent DNA repair and cellular recovery processes in cancer cells. However, monolayer cultures differ greatly from the complex environmental conditions generated in solid tumors that develop inhomogeneous hypoxic and necrotic regions. In contrast, multicellular spheroids mimic heterogeneous cellular behavior and the consequent functional characteristics of in vivo solid tumors, and serve as important in vitro model to investigate tumor biology and responses to potential therapeutic agents. The present study compares the radiomodification by 2-DG in monolayer cultures and spheroids of a human glioma cell line (BMG-1) to gain insight into the effects in solid tumors. In spheroids, the glucose consumption (2.1 p mole/cell/h) and lactate production (3.67 p mole/cell/h) was nearly 2-3 fold higher than in monolayer cells (0.83 and 1.43 p mole/cell/h respectively). Presence of 2-DG (5 mM) for 2-4 h inhibited the glucose usage and lactate production by 70% in spheroids, while a 35% reduction was observed in monolayer cells. Under these conditions, 2-DG drastically enhanced the radiation-induced cell death of spheroids (by 2-3 folds); while a 40% increase was observed in monolayer cells. Radiosensitization by 2-DG in monolayer cells was primarily due to an increase in mitotic death (23%) linked to cytogenetic damage (micronuclei), whereas a profound induction of apoptosis (40%) accounted for the sensitization in spheroids. Although the Bcl-2 and Bax levels were significantly higher in spheroids, Bcl-2/Bax ratio was similar in monolayers and spheroids. Comet assay revealed a late onset of DNA breaks in the presence of 2- DG following irradiation only in spheroids, which corroborated well with the late onset of oxidative stress. 2-DG did not induce a significant cell cycle delay in monolayers, while a transient G(2) delay was apparent in spheroids.

1,5-Anhydroglucitol and glycated albumin in glycemia

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

Association of reduced levels of serum 1,5-Anhydro-d-glucitol with carotid atherosclerosis in patients with type 2 diabetes

BACKGROUND

HbA1c level represents mean blood glycemic control. 1,5-Anhydro-d-glucitol (1,5-AG) level reflects glycemic fluctuations, a strong risk factor for the development of macroangiopathy. The present study investigated the relationship between serum 1,5-AG levels and macroangiopathy in patients with type 2 diabetes.

METHODS

A total of 115 consecutive patients with type 2 diabetes, aged 45-79 years, were included. HbA1c, 1,5-AG, and lipid profile were measured. Carotid maximum intima-media thickness (IMT) and plaque score (PS) were determined by carotid sonography. An 1,5-AG level < 14.2 μg/mL was used as a predictor of a post-challenge 2-h blood glucose level > 200 mg/dL. Patients were divided into four groups: A (n=32), HbA1c ≥ 6.5% and 1,5-AG<14.2 μg/mL; B (n=23), HbA1c ≥ 6.5% and 1,5-AG ≥ 14.2 μg/mL; C (n=24), HbA1c < 6.5% and 1,5-AG <14.2 μg/mL; and D (n=36), HbA1c < 6.5% and 1,5-AG ≥ 14.2 μg/mL.

RESULTS

HbA1c level had significant positive correlation with IMT and PS. 1,5-AG level had a significant negative correlation with PS. PS was significantly higher in group C than in group D, but similar to that in group B. In multivariate analysis, HbA1c (β=0.27, p=0.03) and 1,5-AG (β=-0.24, P=0.04) were independent determinants of PS.

CONCLUSIONS

1,5-AG level might provide additional information to identify macroangiopathy of patients with type 2 diabetes, especially in those with excellent HbA1c levels.

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

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

[Indicators of glycemic control --hemoglobin A1c (HbA1c), glycated albumin (GA), and 1,5-anhydroglucitol (1,5-AG)]

The clinical goal of diabetes management is a good quality of life that is not different from that of a healthy subjects. To fulfill the goal, prevention of complications is needed under good glycemic control. Although blood glucose measurement is essential for glycemic control, there are diurnal variations in blood glucose levels. An indicator of long-term glycemic control is necessary. HbA1c is the gold standard measurement for the assessment of glycemic control, and worldwide large scale clinical studies of diabetes complications have greatly valued HbA1c as an indicator of glycemic control. In addition, recently, HbA1c was recommended for use in the diagnosis of diabetes in Japan and in the United States. Although HbA1c is used widely and internationally, international standardization of the HbA1c value has not been achieved. In Japan, from April 2014, it has been decided to adopt the National Glycohemoglobin Standardization Program (NGSP) value, which is used by many countries globally, as the first step toward internationalization. Recently, cardiovascular disease in diabetic patients has been increasing in Japan. Relationships between postprandial hyperglycemia and cardiovascular disease have been noted. Therefore, the correction of postprandial hyperglycemia is one of the important goals of glycemic control to prevent cardiovascular disease. HbA1c or glycated albumin (GA) results from the glycation of hemoglobin or serum albumin and represents 2-month or 2-week glycemia, respectively. In addition, the glycation speed of GA is ten times faster than HbA1c, so GA is likely to reflect the variation in blood glucose and postprandial hyperglycemia in combination with HbA1c and its value. 1,5-anhydroglucitol (AG) is a marker of glycemia-induced glycosuria, since reabsorption of filtered 1,5-AG in the proximal tubule is competitively inhibited by glucose. It is an indicator to identify rapid changes in hyperglycemia. Understanding the characteristics of the indicators above, it is important to use them suitably for each diabetes subject and to recognize glycemic control conditions more accurately.

Glycemic variability is an independent predictive factor for development of hepatic fibrosis in nonalcoholic fatty liver disease

Patients with nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) often have metabolic disorders including insulin resistance and type 2 diabetes mellitus (T2DM). We clarified the predictive factors in glucose metabolism for progression of hepatic fibrosis in patients with NAFLD by the 75-g oral glucose tolerance test (75gOGTT) and a continuous glucose monitoring system (CGMS). One hundred sixty-nine patients (68 female and 101 male patients) with biopsy-proven NAFLD with performance with 75gOGTT were enrolled and divided into four groups according to the stage of hepatic fibrosis (F0–3). The proportion of patients with T2DM significantly gradually increased, HbA1c and the homeostasis model assessment of insulin resistance were significantly elevated, and 1,5-anhydroglucitol (1,5-AG) was remarkably decreased with the progression of fibrosis. In the 75gOGTT, both plasma glucose and insulin secretion were remarkably increased with the progression of fibrosis. The only factor significantly associated with advanced fibrosis was 1,5-AG (P = 0.008) as determined by multivariate logistic regression analysis. We next evaluated the changes in blood glucose during 24 hours by monitoring with the CGMS to confirm the relationship between glycemic variability and progression of fibrosis. Variability of median glucose, standard deviation of median glucose (P = 0.0022), maximum blood glucose (P = 0.0019), and ΔMin–max blood glucose (P = 0.0029) were remarkably higher in severe fibrosis than in mild fibrosis.

Conclusion

Hyperinsulinemia and hyperglycemia, especially glycemic variability, are important predictive factors in glucose impairment for the progression of hepatic fibrosis in NAFLD.

Evaluation of 1,5-anhydroglucitol as a marker for glycemic variability in patients with type 2 diabetes mellitus

1,5-anhydroglucitol (1,5-AG) has been suggested as a marker for short-term glycemic control and postprandial hyperglycemia. However, the role of 1,5-AG in glycemic variability has not been established. The aim of this study was to demonstrate the usefulness of 1,5-AG as a marker for glycemic variability in patients with type 2 diabetes. Sixty patients with type 2 diabetes were enrolled, and a continuous glucose monitoring system (CGMS) was applied for 72 h. Continuous overlapping net glycemic action (CONGA), mean amplitude of glycemic excursion (MAGE), and mean of the daily differences (MODD) were calculated for the assessment of glycemic variability and compared with 1,5-AG. Urinary 8-iso prostaglandin F2α (8-isoPGF2α) was measured to assess oxidative stress. 1,5-AG was correlated with fasting blood glucose, HbA1c, postprandial area under the curve for glucose above 180 mg/dL (AUC-180), and mean post-meal maximum glucose (MPMG). However, 1,5-AG did not show significant correlation with CONGA-1, MAGE, and MODD (R = -0.053, P = 0.689; R = -0.148, P = 0.259; R = -0.123, P = 0.350). In patients with HbA1c ≤ 8.0% (n = 35), 1,5-AG was significantly correlated with HbA1c, mean glucose, postprandial AUC-180, and MPMG. However, in patients with HbA1c > 8.0% (n = 25), 1,5-AG did not show correlation with any glycemic markers. Oxidative stress measured as urine 8-isoPGF2α showed positive correlations with CONGA-1, MAGE, AUC-180, postprandial AUC-180, and MPMG only in men. However, 1,5-AG did not correlate with oxidative stress. Our data suggested a limited usefulness of 1,5-AG in estimating glycemic variability and oxidative stress. 1,5-AG was able to represent mean glucose and postprandial hyperglycemia only in well-controlled diabetic patients.

Evaluation of glycemic variability in well-controlled type 2 diabetes mellitus

AIMS

It is necessary to evaluate glucose variability and postprandial hyperglycemia in patients with well-controlled type 2 diabetes mellitus because of the limitations associated with hemoglobin A1c (HbA1c) measurements. We evaluated parameters reflecting postprandial hyperglycemia and glycemic variability in patients with optimal HbA1c.

PATIENTS AND METHODS

Thirty-nine patients with HbA1c levels below 7% were recruited to the study. A continuous glucose monitoring system (CGMS) was applied for two 72-h periods. 1,5-Anhydroglucitol (1,5-AG) and fructosamine (FA) were measured as parameters for postprandial hyperglycemia and glucose variability. Using CGMS data, the following postprandial hyperglycemia parameters were calculated: mean postprandial maximum glucose (MPMG) and area under the curve for glucose above 180 mg/dL (AUC-180). To measure glycemic variability, we calculated mean amplitude of glucose excursion (MAGE) using a classical (MAGEc) and new method (MAGE group of sign [MAGEgos]).

RESULTS

The baseline HbA1c level was 6.3±0.3%. The mean MPMG was 10.34±1.84 mmol/L, and the mean AUC-180 was 0.17±0.23 mmol/L/day. The mean MAGEgos was 3.27±1.29 mmol/L, and MAGEc was 4.30±1.43 mmol/L, indicating glycemic variability in our patients. The mean levels of 1,5-AG and FA were 16.7±7.4 μg/mL and 273.0±22.5 μmol/L, respectively. In a correlation analysis, FA was significantly correlated with MPMG, AUC-180, MAGEgos, and MAGEc. In contrast, 1,5-AG was only correlated with AUC-180.

CONCLUSIONS

This study demonstrated postprandial hyperglycemia and glycemic variability in subjects with well-controlled diabetes. FA may reflect postprandial hyperglycemia and glycemic variability, but 1,5-AG may be of limited value for assessing glucose variability in patients with well-controlled type 2 diabetes mellitus.

1,5-Anhydroglucitol as a marker of maternal glycaemic control and predictor of neonatal birthweight in pregnancies complicated by type 1 diabetes mellitus

AIMS/HYPOTHESIS

Most pregnant women with type 1 diabetes mellitus achieve HbA1c targets; however, macrosomia remains prevalent and better pregnancy glycaemic markers are therefore needed. 1,5-Anhydroglucitol (1,5-AG) is a short-term marker of glycaemia, reflecting a period of 1 to 2 weeks. Its excretion rate depends on the renal glucose threshold and thus it is unclear whether it may be used in pregnant type 1 diabetes women. We evaluated 1,5-AG as a glycaemic marker and birthweight predictor in pregnant women with type 1 diabetes, and compared its performance with HbA1c.

METHODS

1,5-AG and HbA1c were measured in 82 pregnant women with type 1 diabetes. In addition, 58 continuous glucose monitoring system (CGMS) records were available. Macrosomia was defined as birthweight >90th centile. The data were analysed with Pearson's correlations, and linear and logistic regression models. Receiver operating characteristic (ROC) analysis was used to evaluate third trimester 1,5-AG as a predictor of macrosomia.

RESULTS

Unlike HbA1c, 1,5-AG strongly correlated with CGMS indices: the AUC above 7.8 mmol/l (r = -0.66; p < 0.001), average maximum glucose (r = -0.58; p < 0.001) and mean glucose (r = -0.54; p < 0.001). In the third trimester, 1,5-AG was the strongest predictor of macrosomia, with ROC AUC 0.81 (95% CI 0.70, 0.89). In contrast, HbA1c in the third trimester had a ROC AUC of 0.69 (95% CI 0.58, 0.81). The best discrimination was achieved when both markers were used jointly, yielding a ROC AUC of 0.84 (95% CI 0.76, 0.93).

CONCLUSIONS/INTERPRETATION

In pregnant women with type 1 diabetes, 1,5-AG is a better glycaemic marker than HbA1c, as assessed by CGMS. A decreased third trimester 1,5-AG level, either singly or with HbA1c, is a strong predictor of macrosomia.