Glycemic variability in type 2 diabetes mellitus: oxidative stress and macrovascular complications

Enhancing severe hypoglycemia prediction in type 2 diabetes mellitus through multi-view co-training machine learning model for imbalanced dataset

Patients with type 2 diabetes mellitus (T2DM) who have severe hypoglycemia (SH) poses a considerable risk of long-term death, especially among the elderly, demanding urgent medical attention. Accurate prediction of SH remains challenging due to its multifaced nature, contributed from factors such as medications, lifestyle choices, and metabolic measurements. In this study, we propose a systematic approach to improve the robustness and accuracy of SH predictions using machine learning models, guided by clinical feature selection. Our focus is on developing long-term SH prediction models using both semi-supervised learning and supervised learning algorithms. Using the action to control cardiovascular risk in diabetes trial, which includes electronic health records for over 10,000 individuals, we focus on studying adults with T2DM. Our results indicate that the application of a multi-view co-training method, incorporating the random forest algorithm, improves the specificity of SH prediction, while the same setup with Naive Bayes replacing random forest demonstrates better sensitivity. Our framework also provides interpretability of machine learning models by identifying key predictors for hypoglycemia, including fasting plasma glucose, hemoglobin A1c, general diabetes education, and NPH or L insulins. The integration of data routinely available in electronic health records significantly enhances our model's capability to predict SH events, showcasing its potential to transform clinical practice by facilitating early interventions and optimizing patient management. By enhancing prediction accuracy and identifying crucial predictive features, our study contributes to advancing the understanding and management of hypoglycemia in this population.

Ultra rapid lispro improves postprandial glucose control versus lispro in combination with basal insulin: a study based on CGM in type 2 diabetes in China

Aim

To evaluate the efficacy and safety of URLi (ultra rapid lispro insulin) compared to insulin lispro as bolus insulin with basal insulin using CGM in the individuals with type 2 diabetes(T2D) in China.

Methods

This was a double-blind, randomized, parallel, prospective, phase 3 study. Subjects with uncontrolled T2D were recruited and randomized 1:2 into the insulin lispro and URLi groups. Subjects received a consistent basal insulin regimen during the study and self-administered insulin lispro or URLi before each meal throughout the treatment period. Subjects underwent a 3-day continuous glucose monitoring (CGM) at the baseline and endpoint respectively, and then CGM data were analyzed. The primary endpoint was to compare the difference in postprandial glucose (PPG) control using CGM between the two groups.

Results

A total of 57 subjects with T2D completed the study. Our CGM data showed that postprandial glucose excursions after breakfast (BPPGE) in the URLi group was lower than that in the insulin lispro group (1.59 ± 1.57 mmol/L vs 2.51 ± 1.73 mmol/L, p = 0.046). 1-hour PPG was observed to decrease more in the URLi group than that in the insulin lispro group (-1.37 ± 3.28 mmol/L vs 0.24 ± 2.58 mmol/L, p = 0.047). 2-hour PPG was observed to decrease more in the URLi group than that in the insulin lispro group (-1.12 ± 4.00 mmol/L vs 1.22 ± 2.90 mmol/L, p = 0.021). The mean HbA1c level decreased by 1.1% in the URLi group and 0.99% in the insulin lispro group, with no treatment difference (p = 0.642). In the CGM profile, TBR was not significantly different between the two groups (p = 0.743). The weight gain also did not differ between the two groups (p = 0.303).

Conclusion

URLi can control breakfast PPG better than insulin lispro in adults with T2D in China, while it is non-inferior in improving HbA1c. The incidence of hypoglycemic and weight gain were similar between the two groups.

Longitudinal HbA1c trajectory modelling reveals the association of HbA1c and risk of hospitalization for heart failure for patients with type 2 diabetes mellitus

BACKGROUND

Inconsistent conclusions in past studies on the association between poor glycaemic control and the risk of hospitalization for heart failure (HHF) have been reported largely due to the analysis of non-trajectory-based HbA1c values. Trajectory analysis can incorporate the effects of HbA1c variability across time, which may better elucidate its association with macrovascular complications. Furthermore, studies analysing the relationship between HbA1c trajectories from diabetes diagnosis and the occurrence of HHF are scarce.

METHODS

This is a prospective cohort study of the SingHealth Diabetes Registry (SDR). 17,389 patients diagnosed with type 2 diabetes mellitus (T2DM) from 2013 to 2016 with clinical records extending to the end of 2019 were included in the latent class growth analysis to extract longitudinal HbA1c trajectories. Association between HbA1c trajectories and risk of first known HHF is quantified with the Cox Proportional Hazards (PH) model.

RESULTS

5 distinct HbA1c trajectories were identified as 1. low stable (36.1%), 2. elevated stable (40.4%), 3. high decreasing (3.5%), 4. high with a sharp decline (10.8%), and 5. moderate decreasing (9.2%) over the study period of 7 years. Poorly controlled HbA1c trajectories (Classes 3, 4, and 5) are associated with a higher risk of HHF. Using the diabetes diagnosis time instead of a commonly used pre-defined study start time or time from recruitment has an impact on HbA1c clustering results.

CONCLUSIONS

Findings suggest that tracking the evolution of HbA1c with time has its importance in assessing the HHF risk of T2DM patients, and T2DM diagnosis time as a baseline is strongly recommended in HbA1c trajectory modelling. To the authors' knowledge, this is the first study to identify an association between HbA1c trajectories and HHF occurrence from diabetes diagnosis time.

Glycaemia dynamics in gestational diabetes mellitus

Pregnant women may develop gestational diabetes mellitus (GDM), a disease of pregnancy characterised by maternal and fetal hyperglycaemia with hazardous consequences to the mother, the fetus, and the newborn. Maternal hyperglycaemia in GDM results in fetoplacental endothelial dysfunction. GDM-harmful effects result from chronic and short periods of hyperglycaemia. Thus, it is determinant to keep glycaemia within physiological ranges avoiding short but repetitive periods of hyper or hypoglycaemia. The variation of glycaemia over time is defined as 'glycaemia dynamics'. The latter concept regards with a variety of mechanisms and environmental conditions leading to blood glucose handling. In this review we summarized the different metrics for glycaemia dynamics derived from quantitative, plane distribution, amplitude, score values, variability estimation, and time series analysis. The potential application of the derived metrics from self-monitoring of blood glucose (SMBG) and continuous glucose monitoring (CGM) in the potential alterations of pregnancy outcome in GDM are discussed.

Fasting Glucose of 6.1 mmol/L as a Possible Optimal Target for Type 2 Diabetic Patients with Insulin Glargine: A Randomized Clinical Trial

To observe whether different insulin glargine titration algorithms based on fasting blood glucose (FBG) levels lead to different glycaemic variations (GVs) in type 2 diabetes (T2D) patients, a prospective, randomized, single-centre, comparative, three-arm parallel-group, open-label, treat-to-target, 24-week study was performed. A total of 71 uncontrolled T2D patients were recruited and randomized 1 : 3 : 3 into Groups 1, 2, and 3 (insulin titration goals of FBG ≤ 5.6, ≤6.1, and ≤7.0) for this study. The initiated insulin glargine dose was recommended at 0.2 U/kg/day and was then titrated following the FBG target. Patients were subjected to two 3-day continuous glucose monitoring (CGM) at baseline and the endpoint, wherein the CGM data were analysed, and the study's primary endpoint was the difference in 24 hrs mean amplitude of glycaemic excursion (MAGE) among the three groups. We observed that patients in the three groups had similar MAGE levels at the endpoint; however, Group 2 achieved a significant decrease in the MAGE level from baseline to the endpoint as compared to Groups 1 and 3 (all p < 0.05). We also observed that these patients had significant glycated haemoglobin A1c (HbA1c) value improvements as compared to the other two groups (all p < 0.05). Therefore, choosing an FBG level of 6.1 mmol/L as an insulin titration target provided significant GVs and HbA1c value improvements in T2D patients. Moreover, our data indicated that an FBG of 6.1 mmol/L could possibly be an insulin glargine titration target in T2D patients.

Paeoniflorin ameliorates glycemic variability-induced oxidative stress and platelet activation in HUVECs and DM rats

Glycemic variability (GV) plays an important role in the pathogenesis of vascular complications associated with diabetes mellitus (DM). Paeoniflorin is an effective Chinese traditional medicine with anti-inflammatory and immune-regulatory effects. Previous studies implicated the beneficial effects of paeoniflorin in treatment for diabetic complications, such as type 2 diabetic nephropathy and diabetes with myocardial ischemic injury. Current evidence suggests that oxidative stress and platelet activation, as well as their interaction, are potentially associated with GV and involved in the pathogenesis of diabetes-associated vascular complications. This study aimed to explore the effects of paeoniflorin on oxidative stress and platelet activation, using human umbilical vein endothelial cells (HUVECs) cultured with different glucose concentrations, and streptozotocin-induced diabetic rats fed different glycemic index diets. Paeoniflorin treatment effectively improved the morphology and cell viability of HUVECs under glucose fluctuation. Moreover, the platelet aggregation rate, CD62p expression, and reactive oxygen species (ROS) concentration decreased, while glutathione peroxidase (GSH-px) levels increased in paeoniflorin-treated groups. In conclusion, our study found that paeoniflorin ameliorates oxidative stress and platelet activation induced by glycemic variability both in vivo and in vitro, suggesting a novel potential strategy for treatment of diabetic complications.

Glycemic variability (GV) plays an important role in the pathogenesis of vascular complications associated with diabetes mellitus (DM).

Glycemic variability as predictor of contrast-induced nephropathy in diabetic patients with acute myocardial infarction undergoing percutaneous coronary intervention

Background

Contrast-induced nephropathy (CIN) is a frequent complication in patients undergoing percutaneous coronary intervention (PCI). Diabetes mellitus (DM) and acute myocardial infarction (AMI) are associated with an increased risk of CIN. However, it remains unclear whether glycemic variability (GV) has the important prognostic significance of CIN in diabetic patients with AMI undergoing PCI. We conducted this study to investigate the independent prognostic value of the in-hospital GV in diabetic patients who presented with AMI and were treated with PCI.

Methods

The study group comprised 252 diabetic patients with AMI who underwent PCI and were assigned to CINand non-CIN groups. A continuous glucose monitoring system (CGMS) was used to determine the mean amplitude of glycemic excursion (MAGE), a representative index of GV. Independent risk factors for CIN were determined by multivariate logistic regression analysis (MLRA), and receiver-operating characteristic (ROC) analysis was used to measure the prognostic potential of GV.

Results

A total of 55 patients had CIN and they showed markedly elevated MAGE compared with the non-CIN group. MLRA revealed that MAGE had potential to independently predict CIN. The area under the ROC curve, optimal cut-point value, sensitivity and specificity for MAGE were 0.739, 2.95, 70.91% and 61.42%, respectively.

Conclusions

In diabetic AMI patients undergoing PCI, high GV is associated with increased risk of CIN.

Efficacy of Vildagliptin Added to Continuous Subcutaneous Insulin Infusion (CSII) in Hospitalized Patients with Type 2 Diabetes

INTRODUCTION

The aim of this study was to compare the efficacy of vildagliptin as add-on therapy to short-term continuous subcutaneous insulin infusion (CSII) with CSII monotherapy in hospitalized patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 200 hospitalized patients with inadequately controlled T2DM were randomized into groups, with one group receiving CSII monotherapy (CSII group, n =100) and the other group receiving CSII plus vildagliptin as add-on (CSII + Vig group, n = 100). Of these, 191 completed the 7-day trial (CSII group, n = 99; CSII + Vig group, n = 92) and included in the analysis. The glycemic control and variability of the patients were measured using all-day capillary blood glucose (BG) monitoring. Weight and fasting C-peptide levels were evaluated before and after the interventions.

RESULTS

Mean BG concentrations during the whole treatment period were lower and the time to reach target BG was reduced in the CSII + Vig group compared with the CSII group (9.89 ± 3.37 vs. 9.46 ± 3.23 mmol/L, P < 0.01; 129 ± 4 vs. 94 ± 5 h, P < 0.01, respectively). Similarly, the indicators of glycemic variability, namely the standard deviation of BG and the largest amplitude of glycemic excursion, were significantly decreased in the CSII + Vig group compared with the CSII group (2.68 ± 1.05 vs. 2.39 ± 1.00 mmol/L, P < 0.01; 7.19 ± 2.86 vs. 6.23 ± 2.73 mmol/L, P < 0.01, respectively).

CONCLUSIONS

Short-term CSII with vildagliptin as add-on therapy may be an optimized treatment for hospitalized patients with T2DM compared with short-term CSII monotherapy.

Therapeutic Options Targeting Oxidative Stress, Mitochondrial Dysfunction and Inflammation to Hinder the Progression of Vascular Complications of Diabetes

Type 2 diabetes mellitus is a leading cause of morbidity and mortality worldwide, given its serious associated complications. Despite constant efforts and intensive research, an effective, ubiquitous treatment still eludes the scientific community. As such, the identification of novel avenues of research is key to the potential discovery of this evasive "silver bullet." We focus on this review on the matter of diabetic injury to endothelial tissue and some of the pivotal underlying mechanisms, including hyperglycemia and hyperlipidemia evoked oxidative stress and inflammation. In this sense, we revisited the most promising therapeutic interventions (both non-pharmacological and antidiabetic drugs) targeting oxidative stress and inflammation to hinder progression of vascular complications of diabetes. This review article gives particular attention to the relevance of mitochondrial function, an often ignored and understudied organelle in the vascular endothelium. We highlight the importance of mitochondrial function and number homeostasis in diabetic conditions and discuss the work conducted to address the aforementioned issue by the use of various therapeutic strategies. We explore here the functional, biochemical and bioenergetic alterations provoked by hyperglycemia in the endothelium, from elevated oxidative stress to inflammation and cell death, as well as loss of tissue function. Furthermore, we synthetize the literature regarding the current and promising approaches into dealing with these alterations. We discuss how known agents and therapeutic behaviors (as, for example, metformin, dietary restriction or antioxidants) can restore normality to mitochondrial and endothelial function, preserving the tissue's function and averting the aforementioned complications.

Association of Higher Circulating Insulin Antibody with Increased Mean Amplitude Glycemic Excursion in Patients with Type 2 Diabetes Mellitus: A Cross-Sectional, Retrospective Case-Control Study

Insulin antibody (IA) may potentially affect a patient's glycemic control due to its variability in both binding and/or releasing insulin. However, the association between IA titer and daily glycemic variability (GV) is still unknown. We thus performed this cross-sectional, retrospective case-control study to assess the relationship between IA titer and mean amplitude glycemic excursion (MAGE) in type 2 diabetes mellitus (T2DM) patients using a continuous glucose monitoring (CGM) system. We recruited 100 eligible patients (IA > 5%, IA positive) and divided them into two groups-a low (L) group and a high (H) group-based on their IA titer. The control (C) group consisted of 47 patients (IA ≤ 5%, IA negative) matched for age, BMI, gender, and glycosylated hemoglobin A1c (HbA1c). The CGM determined the GV of enrolled patients. The primary outcome was the relationship between the IA titer and the MAGE, and the secondary outcome was the differences of GV among the three groups. We found that patients in the H group had higher levels of blood glucose fluctuation parameters than those in the L and C groups. The Ln(IA) was positively correlated with Ln(MAGE) even after adjusting for age, gender, BMI, HbA1c, and fasting and postprandial C-peptide(r = 0.423, p < 0.001). Multiple linear stepwise regression analysis revealed that Ln(IA) was an independent factor of Ln(MAGE) (beta = 0.405, p < 0.001). In conclusion, the higher circulating IA titer was associated with increased MAGE in T2DM patients, indicating that those patients with elevated IA titer should receive GV assessment and individualized treatment.

Long-term Effect of Islet Transplantation on Glycemic Variability

Islet transplantation has been reported to restore normoglycemia and the overall metabolic control in type 1 diabetes mellitus (DM). In the most experienced centers, islet transplantation clinical outcome is similar to that of the whole pancreas transplantation. Long-term islet transplantation function remains a very interesting matter worth discussing. A progressive islet function decrease was reported, probably due to islet exhaustion. In 5 islet-transplanted patients with at least 3-yr follow-up and still insulin independent, their glycemic control was characterized by a blinded retrospective continuous glucose monitoring system (CGMS). Islet transplantation restored glycemic control and glucose variability. Data were compared with patients in the waiting list. All the parameters of glycemic variability tested had improved significantly in patients who had islet transplantation compared with those patients who were on the waiting list. In conclusion, islet transplantation is able to maintain a proper glucose control and normalize glycemic variability in selected patients. A blinded retrospective CGMS is a useful method to characterize glucose homeostasis deeply in vivo in islet-transplanted patients.

Particulate matter and markers of glycemic control and insulin resistance in type 2 diabetic patients: result from Wellcome Trust Genetic study

There is growing evidence that air pollution is associated with increased risk of type 2 diabetes (T2DM). However, information related to whether particulate matter (PM) contributing to worsened metabolic control in T2DM patients is inconsistent. We examined the association of PM₁₀ exposure with glucose-function parameters in young-onset T2DM patients. We investigated the association between a year ambient concentration of PM₁₀ at residential places, using AERMOD dispersion model, with fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), 2 h post meal plasma glucose (2hPG), homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-β) and disposition index (DI) in 1213 diabetic patients from the Wellcome Trust Genetic study at the Diabetes Unit, KEM Hospital Research Center, Pune, India. We used linear regression models and adjusted for a variety of individual and environmental confounding variables. Possible effect modification by age, gender, waist-to-hip ratio (WHR) and smoking status were investigated. Sensitivity analysis assessed the impact of relative humidity (RH) and temperature a day before examination and anti-diabetic and HHR medication (Hydralazine, Hydrochlorothiazide and Reserpine). We found that 1 SD increment in background concentration of PM₁₀ at residential places (43.83 µg/m³) was significantly associated with 2.25 mmol/mol and 0.38 mmol/l increase in arithmetic means of HbA1c and 2hPG, respectively. A similar increase in PM₁₀ was also associated with 4.89% increase in geometric mean of HOMA-IR. The associations remained significant after adjustment to RH and temperature, and WHR and smoking enhanced the size of the effect. Our study suggests that long-term exposure to PM₁₀ is associated with higher glycaemia and insulin resistance. In context of our previous demonstration of association of SO₂ and NO _x and plasma C-reactive protein, we suggest that air pollution could influence progression of diabetes complications. Prospective studies and interventions are required to define mechanism and confirm causality.

Periodontal Disease and Diabetes: Perceptions, Communication, and Referral Between Rural Primary Care Physicians and Dentists

BACKGROUND AND OBJECTIVE

Connections between oral health and systemic disease, specifically diabetes, are well described in the literature. Screening strategies for diabetes in dental settings and dental screenings in diabetes care settings exist. The purpose of this study was to evaluate the communication and referral patterns between dentists and physicians in a rural state with respect to recognition of dental disease and diabetes.

METHODS

Surveys were sent to the members of the North Dakota Academy of Family Physicians, the North Dakota Medical Association, and the North Dakota Dental Association.

RESULTS

Overall, 85 responses were collected, with 100% of responding physicians and dentists answering "yes" to a perceived link between oral and systemic health. Physician respondents tended to make a referral for dental evaluation in patients with prediabetes or diabetes more often than dentists referred patients with periodontal disease to physicians.

CONCLUSION

Awareness of the link between dental disease and diabetes and of the need for referral is higher among physicians than among dentists. Opportunity exists to improve awareness and increase referrals.

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.

Comparison of the Effects of Continuous Subcutaneous Insulin Infusion and Add-On Therapy with Sitagliptin in Patients with Newly Diagnosed Type 2 Diabetes Mellitus

To identify a new regimen to optimize treatment for patients with newly diagnosed type 2 diabetes (T2DM) by short-term continuous subcutaneous insulin infusion (CSII) alone. Methods. 60 patients with newly diagnosed T2DM were randomized into two groups (n = 30 each) and treated for 2 weeks with CSII alone (CSII group) or with CSII plus sitagliptin (CSII + Sig group). The glycemic variability of the patients was measured using a continuous glucose monitoring system (CGMS) for the last 72 hours. A standard meal test was performed before and after the interventions, and the levels of glycated albumin, fasting glucose, fasting C-peptide, postprandial 2 h blood glucose, and postprandial 2 h C-peptide were examined. Results. Compared with the CSII group, the indicators of glycemic variability, such as the mean amplitude of glycemic excursion (MAGE) and the standard deviation of blood glucose (SDBG), were decreased significantly in the CSII + Sig group. The changes before and after treatment in the C-peptide reactivity index (ΔCPI) and the secretory unit of islet in transplantation index (ΔSUIT) indicated a significant improvement in the CSII + Sig group. Conclusions. Add-on therapy with sitagliptin may be an optimized treatment for patients with newly diagnosed T2DM compared with short-term CSII alone.

Featured Article: Oxidative stress status and liver tissue defenses in diabetic rats during intensive subcutaneous insulin therapy

Long-term insulin delivery can reduce blood glucose variability in diabetic patients. In this study, its impact on oxidative stress status, inflammation, and liver injury was investigated. Diabetes was induced in Wistar rats with a single dose of streptozotocin (100 mg/kg). Untreated rats and rats administered Insuplant® (2 UI/200 g/day) through a subcutaneous osmotic pump for one or four weeks were compared with non-diabetic controls. Body weight, fructosamine level, total cholesterol, Insulin Growth Factor-1 (IGF-1) level, lipid peroxidation, and total antioxidant capacity were measured. Hepatic injury was determined through the measurement of glycogen content, reactive oxygen species (ROS) production, and macrophage infiltration. Liver oxidative stress status was evaluated through the measurement of superoxide dismutase (SOD), catalase (CAT), and nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase) expression, and p38 mitogen-activated protein kinase (p38MAPK) activation. Induction of diabetes led to increased plasma oxidative stress and inflammation. Moreover, ROS production and macrophage infiltration increased in addition to SOD, CAT, and NADPH oxidase expression. Intensive insulin therapy improved metabolic control in diabetic animals as seen by a restoration of hepatic glycogen, plasma IGF-1 levels, and a decrease in plasma oxidative stress. However, insulin treatment did not result in a decrease in acute inflammation in diabetic rats as seen by continued ROS production and macrophage infiltration in the liver, and a decrease of p38MAPK activation. These results suggest that the onset of diabetes induces liver oxidative stress and inflammation, and that subcutaneous insulin administration cannot completely reverse these changes. Targeting oxidative stress and/or inflammation in diabetic patients could be an interesting strategy to improve therapeutic options.

Effects of beta-carotene fortified synbiotic food on metabolic control of patients with type 2 diabetes mellitus: A double-blind randomized cross-over controlled clinical trial

BACKGROUND & AIMS

The aim of the present study was to determine the beneficial effects of beta-carotene fortified synbiotic food intake on metabolic status in patients with type 2 diabetes mellitus (T2DM).

METHODS

This randomized double-blinded placebo-controlled crossover clinical trial was conducted among 51 patients with T2DM. Individuals were randomly assigned to take either a beta-carotene fortified synbiotic (n = 51) or control food (n = 51) for 6 weeks. The beta-carotene fortified synbiotic was containing Lactobacillus sporogenes (1 × 10(7) CFU), 0.1 g inulin and 0.05 g beta-carotene. Control food (the same substance without probiotic, inulin and beta-carotene) was packed in identical 9-g packages. Patients were requested to use the beta-carotene fortified synbiotic and control foods three times a day.

RESULTS

Beta-carotene fortified synbiotic food consumption resulted in a significant decrease in insulin (-1.00 ± 7.90 vs. +3.68 ± 6.91 μIU/mL, P = 0.002), HOMA-IR (-0.73 ± 3.96 vs. +1.82 ± vbnm4.09, P = 0.002), HOMA-B (-0.52 ± 19.75 vs. +8.71 ± 17.15, P = 0.01), triglycerides (-2.86 ± 49.53 vs. +20.14 ± 50.10 mg/dL, P = 0.02), VLDL-cholesterol levels (-0.57 ± 9.90 vs. +4.03 ± 10.02 mg/dL, P = 0.02) and total-/HDL-cholesterol ratio (-0.01 ± 1.08 vs. +0.64 ± 0.81, P = 0.001) compared to the control food. In addition, beta-carotene fortified synbiotic food consumption led to elevated plasma nitric oxide (NO) (+6.83 ± 16.14 vs. -3.76 ± 16.47 μmol/L, P = 0.001) and glutathione (GSH) (+36.58 ± 296.71 vs. -92.04 ± 243.05 μmol/L, P = 0.01).

CONCLUSIONS

Beta-carotene fortified synbiotic food intake in patients with T2DM for 6 weeks had favorable effects on insulin, HOMA-IR, HOMA-B, triglycerides, VLDL-cholesterol, total-/HDL-cholesterol ratio, NO and GSH levels.

Insulin and GH-IGF-I axis: endocrine pacer or endocrine disruptor?

Growth hormone/insulin-like growth factor (IGF) axis may play a role in maintaining glucose homeostasis in synergism with insulin. IGF-1 can directly stimulate glucose transport into the muscle through either IGF-1 or insulin/IGF-1 hybrid receptors. In severely decompensated diabetes including diabetic ketoacidosis, plasma levels of IGF-1 are low and insulin delivery into the portal system is required to normalize IGF-1 synthesis and bioavailability. Normalization of serum IGF-1 correlated with the improvement of glucose homeostasis during insulin therapy providing evidence for the use of IGF-1 as biomarker of metabolic control in diabetes. Taking apart the inherent mitogenic discussion, diabetes treatment using insulins with high affinity for the IGF-1 receptor may act as an endocrine pacer exerting a cardioprotective effect by restoring the right level of IGF-1 in bloodstream and target tissues, whereas insulins with low affinity for the IGF-1 receptor may lack this positive effect. An excessive and indirect stimulation of IGF-1 receptor due to sustained and chronic hyperinsulinemia over the therapeutic level required to overtake acute/chronic insulin resistance may act as endocrine disruptor as it may possibly increase the cardiovascular risk in the short and medium term and mitogenic/proliferative action in the long term. In conclusion, normal IGF-1 may be hypothesized to be a good marker of appropriate insulin treatment of the subject with diabetes and may integrate and make more robust the message coming from HbA1c in terms of prediction of cardiovascular risk.

Protective and therapeutic effectiveness of taurine in diabetes mellitus: a rationale for antioxidant supplementation

Taurine, 2-amino ethanesulfonic acid, is a conditionally essential β amino acid which is not utilized in protein synthesis. Taurine is one of the most abundant free amino acids in mammals tissues and is one of the three well-known sulfur-containing amino acids; the others are methionine and cysteine which are considered as the precursors for taurine synthesis. Different scientific studies emphasize on the cytoprotective properties of taurine which included antioxidation, antiapoptosis, membrane stabilization, osmoregulation, and neurotransmission. Protective and therapeutic ameliorations of oxidative stress-induced pathologies were also attributed to taurine both in experimental and human models. Data demonstrating the beneficial effectiveness of taurine against type 1 and type 2 diabetes mellitus and their complications are growing and providing a better understanding of the underlying molecular mechanisms. Although the clinical studies are limited compared to the experimental ones, the present updated systematic review of the literature is set up to provide experimental and clinical evidences regarding the effectiveness of taurine in the context of diabetes mellitus and its complications. Gathering these scientific effects of taurine on diabetes mellitus could provide the physicians and specially the endocrinologists with a comprehensive overview on possible trends in the prevention and management of the disease and its complications through antioxidant supplementation.

Consumption of Mesona chinensis attenuates postprandial glucose and improves antioxidant status induced by a high carbohydrate meal in overweight subjects

Edible plants constitute a potential source for controlling postprandial hyperglycemia and oxidative stress. The objective of this study was to investigate in vitro antioxidant and intestinal α-glucosidase inhibitory activities of Mesona chinensis (MC). In addition, the acute effect of MC on postprandial glucose and plasma antioxidant status after the consumption of a high carbohydrate (HC) meal by overweight subjects was also determined. The results showed that total phenolic and flavonoid contents in the extract were 212.37 ± 5.64 mg gallic acid equivalents/g dried extract and 23.44 ± 2.50 mg catechin equivalents/g dried extract, respectively. MC extract markedly inhibited the intestinal maltase and sucrose with the IC50 values of 4.66 ± 0.22 mg/mL and 1.30 ± 0.43 mg/mL, respectively. However, MC extract had no inhibitory activity against pancreatic α-amylase. In addition, MC extract had antioxidant properties including DPPH radical scavenging activity, superoxide radical scavenging activity (SRSA), hydroxyl radical scavenging activity (HRSA), trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and ferrous ion cheating activity (FICP). The significant decrease in postprandial plasma glucose, triglyceride and malondialdehyde levels, and the increase in plasma antioxidant capacity (FRAP and ORAC) were observed in overweight subjects receiving a HC meal together with MC extract (1 g). The finding supports that MC helps normalize and enhance antioxidant defense induced by a HC meal, suggesting that MC may have the potential for the prevention of chronic conditions and diseases associated with overweight and obesity.

Molecular mechanisms of vascular dysfunction and cardiovascular biomarkers in type 2 diabetes

Prevalence of obesity and type 2 diabetes (T2DM) is alarmingly increasing worldwide. Albeit advances in therapy have reduced morbidity and mortality in T2DM, cardiovascular risk is far to be eradicated and mechanism-based therapeutic approaches are in high demand. In this perspective, deciphering novel molecular networks of vascular disease will be instrumental to develop novel diagnostic and therapeutic strategies in people affected by diabetes. There is therefore a need to address current knowledge gaps in disease aetiology in order to support innovation in diagnosis and treatment. Unfortunately, we are still lacking cost-effective markers able to identify atherosclerotic vascular disease at an early stage. The issue of risk stratification deserves attention because not every T2DM patient carries the same degree of inflammation and oxidative stress. The diversity of metabolic phenotypes with different outcomes underscores the need for cardiovascular risk stratification within such heterogeneous population. Early predictors of vascular damage are mandatory to implement intensive treatment strategies and, hence, reduce cardiovascular disease burden in this setting. In this review we critically discuss novel molecular mechanisms of diabetic vascular disease and their possible translation to the clinical setting.

A systematic review of type 2 diabetes mellitus and hypertension in imaging studies of cognitive aging: time to establish new norms

The rising prevalence of type 2 diabetes (T2DM) and hypertension in older adults, and the deleterious effect of these conditions on cerebrovascular and brain health, is creating a growing discrepancy between the "typical" cognitive aging trajectory and a "healthy" cognitive aging trajectory. These changing health demographics make T2DM and hypertension important topics of study in their own right, and warrant attention from the perspective of cognitive aging neuroimaging research. Specifically, interpretation of individual or group differences in blood oxygenation level dependent magnetic resonance imaging (BOLD MRI) or positron emission tomography (PET H2O(15)) signals as reflective of differences in neural activation underlying a cognitive operation of interest requires assumptions of intact vascular health amongst the study participants. Without adequate screening, inclusion of individuals with T2DM or hypertension in "healthy" samples may introduce unwanted variability and bias to brain and/or cognitive measures, and increase potential for error. We conducted a systematic review of the cognitive aging neuroimaging literature to document the extent to which researchers account for these conditions. Of the 232 studies selected for review, few explicitly excluded individuals with T2DM (9%) or hypertension (13%). A large portion had exclusion criteria that made it difficult to determine whether T2DM or hypertension were excluded (44 and 37%), and many did not mention any selection criteria related to T2DM or hypertension (34 and 22%). Of all the surveyed studies, only 29% acknowledged or addressed the potential influence of intersubject vascular variability on the measured BOLD or PET signals. To reinforce the notion that individuals with T2DM and hypertension should not be overlooked as a potential source of bias, we also provide an overview of metabolic and vascular changes associated with T2DM and hypertension, as they relate to cerebrovascular and brain health.

The association between different A1C-based measures of glycemia and risk of cardiovascular disease hospitalization

OBJECTIVE We tested whether average monthly glycemic burden (AMGB), a marker of hyperglycemia that is a function of the extent and duration that A1C exceeded 7%, indicated greater risk of cardiovascular disease (CVD) than traditional A1C measures. RESEARCH DESIGN AND METHODS Using a case-control design, we studied 2,456 members of Kaiser Permanente Northwest with type 2 diabetes: 1,228 who experienced a CVD hospitalization, matched on age, sex, and duration of diabetes to 1,228 patients who were not hospitalized for CVD. We calculated AMGB from diabetes diagnosis until CVD hospitalization as a function of the difference between each actual or interpolated A1C measurement and 7%, resulting in an area under the curve estimate of hyperglycemic exposure, adjusted for number of months of observation. We used conditional logistic regression to compare the association between several A1C-based measures of glycemia and CVD, controlling for clinical characteristics and comorbidities. RESULTS AMGB was associated with increased CVD risk of 29% (odds ratio 1.29 [95% CI 1.16-1.44]; P < 0.001), while mean A1C was associated with a 22% risk increase (1.22 [1.09-1.37]; P < 0.001). A1C ever exceeding 7% was associated with increased CVD risk of 39% (1.39 [1.08-1.79]; P = 0.010). No model with a glycemia measure provided substantially more information than an identical model without a glycemia measure. CONCLUSIONS AMGB demonstrated somewhat greater CVD risk than mean A1C, but its clinical usefulness may be limited. A1C ever rising above 7% (53 mmol/mol) was a simple predictor of CVD risk that may have important clinical ramifications for newly diagnosed patients.

Pathogenesis of chronic hyperglycemia: from reductive stress to oxidative stress

Chronic overnutrition creates chronic hyperglycemia that can gradually induce insulin resistance and insulin secretion impairment. These disorders, if not intervened, will eventually be followed by appearance of frank diabetes. The mechanisms of this chronic pathogenic process are complex but have been suggested to involve production of reactive oxygen species (ROS) and oxidative stress. In this review, I highlight evidence that reductive stress imposed by overflux of NADH through the mitochondrial electron transport chain is the source of oxidative stress, which is based on establishments that more NADH recycling by mitochondrial complex I leads to more electron leakage and thus more ROS production. The elevated levels of both NADH and ROS can inhibit and inactivate glyceraldehyde 3-phosphate dehydrogenase (GAPDH), respectively, resulting in blockage of the glycolytic pathway and accumulation of glycerol 3-phospate and its prior metabolites along the pathway. This accumulation then initiates all those alternative glucose metabolic pathways such as the polyol pathway and the advanced glycation pathways that otherwise are minor and insignificant under euglycemic conditions. Importantly, all these alternative pathways lead to ROS production, thus aggravating cellular oxidative stress. Therefore, reductive stress followed by oxidative stress comprises a major mechanism of hyperglycemia-induced metabolic syndrome.

Differential effects of vildagliptin and glimepiride on glucose fluctuations in patients with type 2 diabetes mellitus assessed using continuous glucose monitoring

AIM

To assess whether there is a difference in the effects of vildagliptin and glimepiride on glucose fluctuation in patients with type 2 diabetes mellitus (T2DM) using continuous glucose monitoring (CGM).

METHODS

This was an open-label, randomized cross-over study conducted in T2DM patients. A total of 24 patients (age: 58.3 ± 5.56 years, baseline HbA1c: 7.6 ± 0.50%) who were on stable metformin monotherapy (500-3000 mg) were enrolled, and all completed the study. Each patient received two 5-day treatments (vildagliptin 50 mg b.i.d. or glimepiride 2 mg q.d.) in a cross-over manner. Various biomarkers and blood glucose concentrations were measured following breakfast. The 24-h glucose profiles were also measured using the CGM device at baseline and after 5 days of treatment, and fluctuations in glucose levels were estimated from CGM data.

RESULTS

Both vildagliptin and glimepiride reduced postprandial glucose levels, based on both CGM data (15% vs. 16%) and measured plasma glucose (13% vs.17%). Vildagliptin showed lower glucose fluctuations than glimepiride as measured by mean amplitude of glycaemic excursions (MAGE, p = 0.1076), standard deviation (s.d., p = 0.1346) of blood glucose rate of change, but did not reach statistical significance attributed to the small sample size. MAGE was reduced by ∼20% with vildagliptin versus glimepiride. Vildagliptin led to statistically significant lowering of the rate of change in the median curve (RCMC) and interquartile range (IQR) of glucose. Treatment with vildagliptin significantly increased the levels of active glucagon-like peptide-1 by 2.36-fold (p ≤ 0.0001) and suppressed glucagon by 8% (p = 0.01), whereas glimepiride significantly increased the levels of insulin and C-peptide by 21% (p = 0.012) and 12% (p = 0.003), respectively.

CONCLUSIONS

Vildagliptin treatment was associated with less fluctuation of glucose levels than glimepiride treatment as assessed by 24-h CGM device, suggesting vildagliptin may have the potential to offer long-term beneficial effects for patients with T2DM in preventing the development of complications of diabetes.

Oxidative stress in diabetes: implications for vascular and other complications

In recent decades, oxidative stress has become a focus of interest in most biomedical disciplines and many types of clinical research. Increasing evidence shows that oxidative stress is associated with the pathogenesis of diabetes, obesity, cancer, ageing, inflammation, neurodegenerative disorders, hypertension, apoptosis, cardiovascular diseases, and heart failure. Based on these studies, an emerging concept is that oxidative stress is the “final common pathway” through which the risk factors for several diseases exert their deleterious effects. Oxidative stress causes a complex dysregulation of cell metabolism and cell–cell homeostasis; in particular, oxidative stress plays a key role in the pathogenesis of insulin resistance and β-cell dysfunction. These are the two most relevant mechanisms in the pathophysiology of type 2 diabetes and its vascular complications, the leading cause of death in diabetic patients.