Association of glycemic variability and the presence and severity of coronary artery disease in patients with type 2 diabetes

BACKGROUND

Glucose variability is one of components of the dysglycemia in diabetes and may play an important role in development of diabetic vascular complications. The objective of this study was to assess the relationship between glycemic variability determined by a continuous glucose monitoring (CGM) system and the presence and severity of coronary artery disease (CAD) in patients with type 2 diabetes mellitus (T2DM).

METHODS

In 344 T2DM patients with chest pain, coronary angiography revealed CAD (coronary stenosis ≥ 50% luminal diameter narrowing) in 252 patients and 92 patients without CAD. Gensini score was used to assess the severity of CAD. All participants' CGM parameters and biochemical characteristics were measured at baseline.

RESULTS

Diabetic patients with CAD were older, and more were male and cigarette smokers compared with the controls. Levels of the mean amplitude of glycemic excursions (MAGE) (3.7 ± 1.4 mmol/L vs. 3.2 ± 1.2 mmol/L, p < 0.001), postprandial glucose excursion (PPGE) (3.9 ± 1.6 mmol/L vs. 3.6 ± 1.4 mmol/L, p = 0.036), serum high-sensitive C-reactive protein (hs-CRP) (10.7 ± 12.4 mg/L vs. 5.8 ± 6.7 mg/L, p < 0.001) and creatinine (Cr) (87 ± 23 mmol/L vs. 77 ± 14 mmol/L, p < 0.001) were significantly higher in patients with CAD than in patients without CAD. Gensini score closely correlated with age, MAGE, PPGE, hemoglobin A1c (HbA1c), hs-CRP and total cholesterol (TC). Multivariate analysis indicated that age (p < 0.001), MAGE (p < 0.001), serum levels of HbA1c (p = 0.022) and hs-CRP (p = 0.005) were independent determinants for Gensini score. Logistic regression analysis revealed that MAGE ≥ 3.4 mmol/L was an independent predictor for CAD. The area under the receiver-operating characteristic curve for MAGE (0.618, p = 0.001) was superior to that for HbA1c (0.554, p = 0.129).

CONCLUSIONS

The intraday glycemic variability is associated with the presence and severity of CAD in patients with T2DM. Effects of glycemic excursions on vascular complications should not be neglected in diabetes.

Impact of admission glycemic variability, glucose, and glycosylated hemoglobin on major adverse cardiac events after acute myocardial infarction

OBJECTIVE

Dysglycemia is associated with poorer prognosis in patients with acute myocardial infarction (AMI). Whether admission glycemic variability (GV) has important value in prognosis of AMI patients is still unknown. The aim of the study is to investigate the prognostic value of admission GV, glucose, and glycosylated hemoglobin (HbA(1c)) in AMI patients.

RESEARCH DESIGN AND METHODS

We measured blood glucose, HbA(1c), and GV on admission in 222 consecutive patients with diagnosed AMI. GV, indicated as the mean amplitude of glycemic excursions (MAGE), was determined by a continuous glucose monitoring system. MAGE was categorized as ≥3.9 or <3.9 mmol/L, admission glucose as ≥8.61 or <8.61 mmol/L, and HbA(1c) as ≥6.5 or <6.5%. Participants were followed up prospectively for 12 months. The relationship of admission MAGE, glucose, and HbA(1c) to the major adverse cardiac event (MACE) of AMI patients was analyzed.

RESULTS

In 222 enrolled patients with AMI, the rate of MACE by MAGE category (<3.9 or ≥3.9 mmol/L) was 8.4 and 24.1%, respectively (P = 0.001), by admission glucose category (<8.61 or ≥8.61 mmol/L) was 10.1 and 21.6%, respectively (P = 0.020), and by HbA(1c) category (<6.5 vs. ≥6.5%) was 10.7 versus 18.7%, respectively (P = 0.091). In multivariate analysis, high MAGE level was significantly associated with incidence of MACE (hazard ratio 2.419 [95% CI 1.273-9.100]; P = 0.017) even after adjusting for Global Registry of Acute Coronary Events risk score, but admission glucose and HbA(1c) was not.

CONCLUSIONS

Elevated admission GV appears more important than admission glucose and prior long-term abnormal glycometabolic status in predicting 1-year MACE in patients with AMI.

Prognostic value of early in-hospital glycemic excursion in elderly patients with acute myocardial infarction

BACKGROUND

Acute phase hyperglycemia has been associated with increased mortality in patients with acute myocardial infarction (AMI). However, the predictive value of glycemic excursion for adverse outcome in elderly AMI patients is not clear. The aim of this study is to investigate the prognostic value of early in-hospital glycemic excursion and hemoglobin A1c (HbA1c) for one-year major adverse cardiac event (MACE) in elderly patients with AMI.

METHODS

We studied 186 elderly AMI patients, whose clinical data were collected and the Global Registry of Acute Coronary Events (GRACE) risk score were calculated on admission. The fluctuations of blood glucose in patients were measured by a continuous glucose monitoring system (CGMS) for 72 hours. Participants were grouped into tertiles of mean amplitude of glycemic excursions (MAGE) and grouped into HbA1c levels (as ≥6.5% or <6.5%). The MACE of patients, including new-onset myocardial infarction, acute heart failure and cardiac death, was documented during one year follow-up. The relationship of MAGE and HbA1c to the incidence of MACE in elderly AMI patients was analyzed.

RESULTS

In all participants, a higher MAGE level was associated with the higher GRACE score (r = 0.335, p < 0.001). The rate of MACE by MAGE tertiles (>3.94 mmol/L, 2.55-3.94 mmol/L or <2.55 mmol/L) was 30.2% vs. 14.8% vs. 8.1%, respectively (p = 0.004); by HbA1c category (≥6.5% vs. <6.5%) was 22.7% vs. 14.4%, respectively (p = 0.148). Elderly AMI patients with a higher MAGE level had a significantly higher cardiac mortality. In multivariable analysis, high MAGE level was significantly associated with incidence of MACE (HR 3.107, 95% CI 1.190-8.117, p = 0.021) even after adjusting for GRACE risk score, but HbA1c was not.

CONCLUSIONS

The early in-hospital intraday glycemic excursion may be an important predictor of mortality and MACE even stronger than HbA1c in elderly patients after AMI.

Association Between Blood Glucose Variability and the Characteristics of Vulnerable Plaque in Elderly Non-ST Segment Elevation Acute Coronary Syndrome Patients

Blood glucose variability is considered to be one of the risk factors for coronary heart disease, and there is growing evidence that blood glucose fluctuation is closely related to the characteristics of plaques. The aim of the study was to investigate the influence of blood glucose variability on the vulnerability of culprit plaques in elderly non-ST segment elevation acute coronary syndrome (NSTE-ACS) patients.Coronary angiography and VH-IVUS were applied to evaluate the components of culprit plaque in NSTE-ACS patients. CGMS monitoring was performed for 72 hours and blood glucose variability was assessed by glycemic excursions (MAGE), absolute means of daily differences (MODD), postprandial glycemic excursions (PPGE), and the largest amplitude of glycemic excursions (LAGE). An oxidative stress indicator (urinary 8-iso-PGF2α) was also tested.Eighty two elderly NSTE-ACS patients were enrolled in this study. Higher glucose variability was associated with the increased culprit plaque instability. MODD was positively correlated with urinary 8-iso-PGF2α. PPGE and urinary 8-iso-PGF2α were independent risk factors for percent fibrous and necrotic volume in culprit plaques (PPGE: β = -0.340, P = 0.024; urinary 8-iso-PGF2α: β = -0.294, P = 0.013).Blood glucose variability is positively related to oxidative stress. With an increase in blood glucose variability, the instability of criminal plaques in elderly NSTE-ACS patients increased.

Comparison of in-hospital glycemic variability and admission blood glucose in predicting short-term outcomes in non-diabetes patients with ST elevation myocardial infarction underwent percutaneous coronary intervention

AIMS

Admission hyperglycemia is associated with increased mortality and major adverse cardiac events (MACE) in patients with or without diabetes mellitus after acute myocardial infarction (AMI). However, effects of glycemic variability (GV) on outcomes of non-diabetes patients with AMI still remains unclear. The aim of this study is to compare the prognostic value of in-hospital GV with admission blood glucose (ABG) for 3-month MACE in non-diabetes patients with ST elevation myocardial infarction (STEMI) who underwent percutaneous coronary intervention (PCI).

METHODS

We analyzed 256 non-diabetes patients with STEMI in study. The GV accessed by mean amplitude of glycemic excursions (MAGE) was calculated from blood glucose profiles of continuous glucose monitoring system (CGMS) during hospitalization. ABG was measured on admission. Main endpoints were 3-month MACE; secondary endpoints were GRACE scores and enzymatic infarct size. Predictive effects of MAGE and ABG on the MACE in patients were analyzed.

RESULTS

In all participants, MAGE level was associated with ABG level (r = 0.242, p < 0.001). Both elevated MAGE levels (p = 0.001) and elevated ABG (p = 0.046) were associated with incidences of short-term MACE. Patients with a higher MAGE level had a significantly higher cardiac mortality (5.8 vs. 0.6%, p = 0.017) and incidence of acute heart failure (12.8 vs. 2.4%, p = 0.001) during 3 months follow-up. In multivariable analysis, high MAGE level (HR 2.165, p = 0.023) was significantly associated with incidence of short-term MACE, but ABG (HR 1.632, p = 0.184) was not. The area under the receiver-operating characteristic curve for MAGE (0.690, p < 0.001) was superior to that for ABG (0.581, p = 0.076).

CONCLUSIONS

To compare with ABG, in-hospital GV may be a more important predictor of short-term MACE and mortality in non-diabetes patients with STEMI treated with PCI.

Carvedilol prevents counterregulatory failure and impaired hypoglycaemia awareness in non-diabetic recurrently hypoglycaemic rats

AIMS/HYPOTHESIS

This study evaluates whether the non-selective β-blocker, carvedilol, can be used to prevent counterregulatory failure and the development of impaired awareness of hypoglycaemia (IAH) in recurrently hypoglycaemic rats.

METHODS

Sprague Dawley rats were implanted with vascular catheters and intracranial guide cannulas targeting the ventromedial hypothalamus (VMH). These animals underwent either three bouts of insulin-induced hypoglycaemia or received three saline injections (control group) over 3 days. A subgroup of recurrently hypoglycaemic animals was treated with carvedilol. The next day, the animals underwent a hypoglycaemic clamp with microdialysis without carvedilol treatment to evaluate changes in central lactate and hormone levels. To assess whether carvedilol prevented IAH, we treated rats that had received repeated 2-deoxyglucose (2DG) injections to impair their awareness of hypoglycaemia with carvedilol and measured food intake in response to insulin-induced hypoglycaemia as a surrogate marker for hypoglycaemia awareness.

RESULTS

Compared with the control group, recurrently hypoglycaemic rats had a ~1.7-fold increase in VMH lactate and this was associated with a 75% reduction in the sympathoadrenal response to hypoglycaemia. Treatment with carvedilol restored VMH lactate levels and improved the adrenaline (epinephrine) responses. In 2DG-treated rats compared with control animals receiving saline, food intake was reduced in response to hypoglycaemia and increased with carvedilol treatment.

CONCLUSIONS/INTERPRETATION

We conclude that carvedilol may be a useful therapy to prevent counterregulatory failure and improve IAH.

Effect of 1,5-anhydroglucitol levels on culprit plaque rupture in diabetic patients with acute coronary syndrome

BACKGROUND

Postprandial hyperglycemia was reported to play a key role in established risk factors of coronary artery diseases (CAD) and cardiovascular events. Serum 1,5-anhydroglucitol (1,5-AG) levels are known to be a clinical marker of short-term postprandial glucose (PPG) excursions. Low serum 1,5-AG levels have been associated with occurrence of CAD. However, the relationship between 1,5-AG levels and coronary plaque rupture has not been fully elucidated. The aim of this study was to evaluate 1,5-AG as a predictor of coronary plaque rupture in diabetic patients with acute coronary syndrome (ACS).

METHODS

A total of 144 diabetic patients with ACS were included in this study. All patients underwent intravascular ultrasound examination, which revealed 49 patients with plaque rupture and 95 patients without plaque rupture in the culprit lesion. Fasting blood glucose (FBG), hemoglobin A1c (HbA1c) and 1,5-AG levels were measured before coronary angiography. Fasting urinary 8-iso-prostaglandin F2α (8-iso-PGF2α) level was measured and corrected by creatinine clearance.

RESULTS

Patients with ruptured plaque had significantly lower serum 1,5-AG levels, longer duration of diabetes, higher HbA1c and FBG levels than patients without ruptured plaque in our study population. In multivariate analysis, low 1,5-AG levels were an independent predictor of plaque rupture (odds ratio 3.421; P = 0.005) in diabetic patients with ACS. The area under the receiver-operating characteristic curve for 1,5-AG (0.658, P = 0.002) to predict plaque rupture was superior to that for HbA1c (0.587, P = 0.087). Levels of 1,5-AG were significantly correlated with urinary 8-iso-prostaglandin F2α levels (r = - 0.234, P = 0.005).

CONCLUSIONS

Serum 1,5-AG may identify high risk for coronary plaque rupture in diabetic patients with ACS, which suggests PPG excursions are related to the pathogenesis of plaque rupture in diabetes.

Admission glycemic variability correlates with in-hospital outcomes in diabetic patients with non-ST segment elevation acute coronary syndrome undergoing percutaneous coronary intervention

OBJECTIVE

The aim of this study is to evaluate the effects of admission glycemic variability (AGV) on in-hospital outcomes in diabetic patients with non-ST segment elevation acute coronary syndrome (NSTE-ACS) undergoing percutaneous coronary intervention (PCI).

METHODS

We studied 759 diabetic patients with NSTE-ACS undergoing PCI. AGV was accessed based on the mean amplitude of glycemic excursions (MAGEs) in the first 24 hours after admission. Primary outcome was a composite of in-hospital events, all-cause mortality, new-onset myocardial infarction, acute heart failure, and stroke. Secondary outcomes were each of these considered separately. Predictive effects of AGV on the in-hospital outcomes in patients were analyzed.

RESULTS

Patients with high MAGE levels had significantly higher incidence of total outcomes (9.9% vs. 4.8%, p=0.009) and all-cause mortality (2.3% vs. 0.4%, p=0.023) than those with low MAGE levels during hospitalization. Multivariable analysis revealed that AGV was significantly associated with incidence of in-hospital outcomes (Odds ratio=2.024, 95% CI 1.105-3.704, p=0.022) but hemoglobin A1c (HbA1c) was not. In the receiver-operating characteristic curve analysis for MAGE and HbA1c in predicting in-hospital outcomes, the area under the curve for MAGE (0.608, p=0.012) was superior to that for HbA1c (0.556, p=0.193).

CONCLUSION

High AGV levels may be closely correlated with increased in-hospital poor outcomes in diabetic patients with NSTE-ACS following PCI.

Association of Isoprostanes-Related Oxidative Stress with Vulnerability of Culprit Lesions in Diabetic Patients with Acute Coronary Syndrome

Urinary excretion of 8-iso-prostaglandin F2α (8-iso-PGF2α), a reliable biomarker for enhanced oxidant stress in vivo, has been described in association with diabetes and coronary heart disease. The aim of this study was to evaluate the relationship between urinary 8-iso-PGF2α levels and the characteristics of coronary culprit lesion in diabetic patients with acute coronary syndrome (ACS). A total of 79 diabetic patients with ACS were included. iMAP intravascular ultrasound (iMAP-IVUS) was performed to evaluate the characteristics of culprit plaques. Fasting urinary 8-iso-PGF2α level was measured and corrected by creatinine clearance. iMAP-IVUS data showed culprit plaques in high urinary 8-iso-PGF2α level patients had a greater percentage of necrotic core and less fibrous components. High urinary 8-iso-PGF2α levels were correlated with increased necrotic plaque components (r = 0.325, P = 0.003). Meanwhile, the presence of thin-capped fibroatheroma (50.0% versus 11.5%, P = 0.003), ruptured plaques (30.8% versus 7.7%, P = 0.035), and thrombus (38.5% versus 7.7%, P = 0.008) were significantly more frequent in the upper tertile of urinary 8-iso-PGF2α levels than in the low tertile. Multivariate analysis showed high levels of urinary 8-iso-PGF2α (OR 4.240, P = 0.007) was independently associated with the presence of vulnerable culprit plaque in diabetic ACS patients. Urinary 8-iso-PGF2α also displayed a significant value in predicting vulnerable plaques in diabetic patients with ACS by constructing the receiver-operating characteristic (ROC) curve (Area under the ROC curve: 0.713, P = 0.001). Urinary 8-iso-PGF2α levels are associated with the vulnerability of the coronary culprit lesion in diabetic patients with ACS and may provide additional information for risk assessment in suspected vulnerable patients.

Carvedilol prevents impairment of the counterregulatory response in recurrently hypoglycaemic diabetic rats

AIM

It has been suggested that repeated activation of the adrenergic system during antecedent episodes of hypoglycaemia contributes to the development of counterregulatory failure. We previously reported that treatment with carvedilol, a non-specific β-blocker, prevented the development of counterregulatory failure and improved hypoglycaemia awareness in recurrently hypoglycaemic non-diabetic rats. The current study investigated whether carvedilol has similar benefits in diabetic rats.

METHODS

Recurrently hypoglycaemic streptozotocin-diabetic rats (STZ+RH) were treated with carvedilol for one week prior to undergoing a hypoglycaemic clamp. Hypoglycaemia awareness was evaluated in streptozotocin-diabetic rats made hypoglycaemia unaware using repeated injections of 2-deoxyglucose.

RESULTS

Compared to hypoglycaemia-naïve STZ-diabetic controls, exogenous glucose requirements were more than doubled in the STZ+RH animals and this was associated with a 49% reduction in the epinephrine response to hypoglycaemia. Treating STZ+RH animals with carvedilol improved the epinephrine response to hypoglycaemia. Of note, neither recurrent hypoglycaemia nor carvedilol treatment affected the glucagon response in diabetic animals. Additionally, carvedilol treatment improved the feeding response to insulin-induced hypoglycaemia in diabetic animals made 'hypoglycaemia unaware' using repeated injections of 2-deoxyglucose, suggesting the treatment improved awareness of hypoglycaemia as well.

CONCLUSION

Our data suggest that carvedilol may be useful in preventing impairments of the sympathoadrenal response and the development of hypoglycaemia unawareness during recurring episodes of hypoglycaemia in diabetic animals.

Urinary 8-iso-prostaglandin F2α as a risk marker for the vulnerability of culprit plaque in diabetic patients with stable coronary artery disease

We evaluated the association of urinary excretion of 8-iso-prostaglandin F2α (8-iso-PGF2α) with the vulnerability of culprit lesions in 156 age- and sex-matched diabetic stable coronary artery disease (CAD) patients with or without thin-capped fibroatheroma (TCFA) identified by iMAP intravascular ultrasound. Fasting urinary 8-iso-PGF2α level was measured and corrected by creatinine clearance. Compared to non-TCFA group, patients with TCFA had higher urinary 8-iso-PGF2α levels [114.6 (71.1, 181.5) vs. 83.0 (63.2, 138.2) pmol/mmolCr, P = 0.012]. Urinary 8-iso-PGF2α level was positively correlated with percent necrotic volume of culprit lesion (r = 0.218, P = 0.006). High urinary 8-iso-PGF2α level (OR 2.941, P = 0.009) was independently associated with the presence of TCFA and displayed a significant value in predicting TCFA plaques in study patients. The current study indicated that urinary 8-iso-PGF2α may be an important surrogate marker for the vulnerability of culprit lesion in diabetic patients with CAD.

Comparison of glycemic variability and glycated hemoglobin as risk factors of coronary artery disease in patients with undiagnosed diabetes

BACKGROUND

The role of chronic hyperglycaemia as a coronary artery disease (CAD) risk factor is well-known, and the glycemic variability is still a matter of debate. The aim of this study was to investigate the association of admission glycemic excursion and hemoglobin A(1c) (HbA(1c)) with the presence and severity of CAD in patients with undiagnosed diabetes mellitus (DM).

METHODS

We studied 286 newly diagnosed DM patients without prior revascularization undergoing coronary angiography for suspected ischaemic chest pain. Patients were grouped into those with CAD and without CAD according to angiographic results. The severity of CAD was assessed using the Gensini score. Glycemic variability, indicated as the mean amplitude of glycemic excursions (MAGE), was determined by a continuous glucose monitoring system. Serum levels of HbA(1c) and high-sensitive C-reactive protein (hs-CRP) as well as plasma concentrations of fasting glucose, lipids and creatinine were measured in all patients. Predictors of CAD were determined using multivariate Logistic regression model and receiver-operating characteristic (ROC) curves.

RESULTS

The newly diagnosed DM patients with CAD were older, and more were male and current cigarette smokers compared with the patients without CAD. The CAD group had significantly higher levels of MAGE and HbA(1c). Individuals with high levels of HbA(1c) (≥ 7%) or MAGE (≥ 3.4 mmol/L) had also significantly higher CAD prevalence. Logistic regression analysis revealed that high MAGE level and high HbA(1c) level were independent predictors for CAD. The area under the receiver-operating characteristic curve for MAGE (0.606, P = 0.005) was superior to that for HbA(1c) (0.582, P = 0.028). Gensini score closely correlated with age, MAGE, HbA(1c), hs-CRP, creatinine and total cholesterol. Multivariate analysis indicated that age (P < 0.001), MAGE (P < 0.001), HbA(1c) (P = 0.022) and hs-CRP (P = 0.005) were independent determinants for Gensini score.

CONCLUSIONS

Both admission glycemic excursion and chronic hyperglycaemia are associated with the severity of CAD in newly diagnosed DM patients. MAGE displays a significant value in predicting CAD in patients with undiagnosed diabetes even more than HbA(1c).

Imaging of atherosclerotic aorta of rabbit model by detection of plaque inflammation with fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography

BACKGROUND

Atherosclerotic plaque rupture is the primary mechanism of thrombosis which plays a key role in the onset of acute coronary syndromes. Detection of these plaques prone to rupture (vulnerable plaque) could be clinically significant for prevention of cardiac events. It has been shown that high metabolism cells have a high uptake of fluorine-18 fluorodeoxyglucose ((18)F-FDG). The objective of this study was to investigate the correlation of FDG uptake and the immuno-histochemistry parameters of plaques, and the effect of atorvastatin on vulnerable atherosclerotic plaque in a rabbit model.

METHODS

Ten male New Zealand White rabbits were divided into three groups as follows: (1) normal control group (n = 2, C group): the animals were fed a standard diet at 120 g/d and were given water ad labium; (2) atherosclerosis group (n = 4, As group): animals were fed with high fat diet for 5 months after aortic endothelia damage; (3) treatment group (atherosclerosis + atorvastatin, n = 4, Statin group): animals were fed with high fat diet for 5 months and then changed into normal chow plus atorvastatin (2.5 mg·d(-1)·kg(-1)) treatment for another 4 months. Then these four rabbits were imaged with fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and sacrificed for pathohistologic studies. FDG uptake by the aorta was expressed as target-to-background ratio (TBR). Maximal standardized uptake value (SUV) was measured over the thoracic and abdominal aortas. The aortic smooth muscle cell (SMC) number, CD-14 antibody positive cell (macrophage) number and the ratio of the thickness of fibrous cap to the thickness of lipid core (cap-to-core ratio) in atherosclerotic plaques were analyzed.

RESULTS

As group showed significantly higher uptake of FDG than C group (SUVs: 0.746 ± 0.172 vs. 0.286 ± 0.073, P < 0.001). After 4 months of atorvastatin treatment and the modification of diet, SUVs decreased significantly (Statin group: 0.550 ± 0.134, compared to As group, P < 0.001). However, no marked difference was found in TBR, the number of macrophages, the number of SMC and the cap-to-core ratio in the aortic segments between Statin group and As group. The correlation of aortic FDG uptake with SMC assessed by histopathology was negatively significant (r = -0.57, P < 0.001). When aortic FDG uptake was expressed as TBR, it correlated significantly (r = 0.69, P < 0.001) with the macrophage number, and also correlated significantly (r = -0.78, P < 0.001) with the cap-to-core ratio.

CONCLUSION

(18)F-FDG PET/CT might serve as a useful non-invasive imaging technique for detection of atherosclerotic plaque and potentially permit monitoring of relative changes in inflammation within the atherosclerotic lesion.

Astrocyte Glycogen Is a Major Source of Hypothalamic Lactate in Rats With Recurrent Hypoglycemia

Lactate is an important metabolic substrate for sustaining brain energy requirements when glucose supplies are limited. Recurring exposure to hypoglycemia (RH) raises lactate levels in the ventromedial hypothalamus (VMH), which contributes to counterregulatory failure. However, the source of this lactate remains unclear. The current study investigates whether astrocytic glycogen serves as the major source of lactate in the VMH of RH rats. By decreasing the expression of a key lactate transporter in VMH astrocytes of RH rats, we reduced extracellular lactate concentrations, suggesting excess lactate was locally produced from astrocytes. To determine whether astrocytic glycogen serves as the major source of lactate, we chronically delivered either artificial extracellular fluid or 1,4-dideoxy-1,4-imino-d-arabinitol to inhibit glycogen turnover in the VMH of RH animals. Inhibiting glycogen turnover in RH animals prevented the rise in VMH lactate and the development of counterregulatory failure. Lastly, we noted that RH led to an increase in glycogen shunt activity in response to hypoglycemia and elevated glycogen phosphorylase activity in the hours following a bout of hypoglycemia. Our data suggest that dysregulation of astrocytic glycogen metabolism following RH may be responsible, at least in part, for the rise in VMH lactate levels.

ARTICLE HIGHLIGHTS

Astrocytic glycogen serves as the major source of elevated lactate levels in the ventromedial hypothalamus (VMH) of animals exposed to recurring episodes of hypoglycemia. Antecedent hypoglycemia alters VMH glycogen turnover. Antecedent exposure to hypoglycemia enhances glycogen shunt activity in the VMH during subsequent bouts of hypoglycemia. In the immediate hours following a bout of hypoglycemia, sustained elevations in glycogen phosphorylase activity in the VMH of recurrently hypoglycemic animals contribute to sustained elevations in local lactate levels.

Comparison of admission glycemic variability and glycosylated hemoglobin in predicting major adverse cardiac events among type 2 diabetes patients with heart failure following acute ST-segment elevation myocardial infarction

BACKGROUND AND OBJECTIVES

Hyperglycemia is associated with adverse outcomes in patients with acute myocardial infarction (AMI) as well as in patients with heart failure. However, the significance of admission glycemic variability (GV) in predicting outcomes among diabetes patients with heart failure (HF) following acute ST-segment elevation myocardial infarction (ASTEMI) remains unclear. This study aims to explore the prognostic value of admission GV and admission glycosylated hemoglobin (HbA1c) levels in individuals diagnosed with type 2 diabetes and HF following ASTEMI.

METHODS

We measured GV and HbA1c upon admission in 484 consecutive patients diagnosed with type 2 diabetes and HF following ASTEMI. GV, indicated as the mean amplitude of glycemic excursions (MAGE), was assessed utilizing a continuous glucose monitoring system (CGMS). admission MAGE values were categorized as < 3.9 or ≥ 3.9 mmol/L, while HbA1c levels were classified as < 6.5 or ≥ 6.5%. Participants were followed up prospectively for 12 months. The relationship of admission MAGE and HbA1c to the major adverse cardiac event (MACE) of patients with type 2 diabetes and HF following ASTEMI was analyzed.

RESULTS

Among the 484 enrolled patients, the occurrence of MACE differed significantly based on MAGE categories (< 3.9 vs. ≥ 3.9 mmol/L), with rates of 13.6% and 25.3%, respectively (P = 0.001). While MACE rates varied by HbA1c categories (< 6.5 vs. ≥ 6.5%) at 15.7% and 21.8%, respectively (P = 0.086). Patients with higher MAGE levels exhibited a notably elevated risk of cardiac mortality and an increased incidence of HF rehospitalization. The Kaplan-Meier curves analysis demonstrated a significantly lower event-free survival rate in the high MAGE level group compared to the low MAGE level group (log-rank test, P < 0.001), while HbA1c did not exhibit a similar distinction. In multivariate analysis, high MAGE level was significantly associated with incidence of MACE (hazard ratio 3.645, 95% CI 1.287-10.325, P = 0.015), whereas HbA1c did not demonstrate a comparable association (hazard ratio 1.075, 95% CI 0.907-1.274, P = 0.403).

CONCLUSIONS

Elevated admission GV emerges as a more significant predictor of 1-year MACE in patients with type 2 diabetes and HF following ASTEMI, surpassing the predictive value of HbA1c.

Monitoring of atherosclerosis evolution by detection of inflammatory states of aortae in a rabbit model using 18F-FDG -PET/CT

AIM

In vivo dynamic evaluation of atherosclerosis could be clinically significant in the prevention of cardiovascular events. We aimed to monitor Fluorine-18 fluorodeoxyglucose (18F-FDG) uptake in different stages of atherosclerosis, and investigate the feasibility of detecting vulnerable plaques using positron emission tomography/computed tomography (PET/CT) angiography.

METHODS

Twenty-two male NZW rabbits were divided into two groups: atherosclerosis group (group A, N.=11) and atherosclerosis and statin group (group S, N.=11). The rabbits underwent two pharmacological triggerings to induce thrombus at the 18th week. In vivo PET/CT scans were performed on four time points: before cholesterol diet (baseline, N.=6), at 8th week (the middle-of-feeding, N.=4), at 18th week (the end-of-feeding, N.=22) and after triggering (post-triggering, N.=15). 18F-FDG uptake by the aorta was expressed as maximal standardized uptake value (SUVmax) and mean SUV (SUVmean). SUVs were measured on serial 7.5 mm arterial segments.

RESULTS

SUVmean and SUVmax were 0.449±0.108 and 0.550±0.132 at baseline, 0.694±0.117 and 0.754±0.129 at the middle-of-feeding, 0.788±0.121 and 0.861±0.139 in group A, and 0.651±0.194 and 0.736±0.243 in group S at the end-of feeding before triggering. SUVmean and SUVmax were 1.128±0.420 and 1.302±0.489 in thrombosis group, 0.774±0.159 and 0.859±0.191 in non-thrombosis group after triggering. Thrombus were identified in 10 of 22 rabbits (45.5%): 8 of 11 (72.3%) in group A, and 2 of 11 (18.2%) in group S (P<0.001).

CONCLUSION

The inflammatory states of atherosclerosis and vulnerable plaque can be detected by quantitative analysis of 18F-FDG uptake. PET/CT may be used for predicting thrombosis events in patients with atherosclerotic disease.