The importance of hyperglycemia in the nonfasting state to the development of cardiovascular disease

Exosomal microRNAs in diabetic heart disease

Diabetes is a metabolic disorder that affects millions of people worldwide. Diabetic heart disease (DHD) comprises coronary artery disease, heart failure, cardiac autonomic neuropathy, peripheral arterial disease, and diabetic cardiomyopathy. The onset and progression of DHD have been attributed to molecular alterations in response to hyperglycemia in diabetes. In this context, microRNAs (miRNAs) have been demonstrated to have a significant role in the development and progression of DHD. In addition to their effects on the host cells, miRNAs can be released into circulation after encapsulation within the exosomes. Exosomes are extracellular nanovesicles ranging from 30 to 180 nm in diameter secreted by all cell types. They carry diverse cargos that are altered in response to various conditions in their parent cells. Exosomal miRNAs have been extensively studied in recent years due to their role and therapeutic potential in DHD. This review will first provide an overview of exosomes, their biogenesis and function, followed by the role of exosomes in cardiovascular disease and then focuses on the known role of exosomes and associated miRNAs in DHD.

Infrared Spectroscopy of Blood

The magnitude of infectious diseases in the twenty-first century created an urgent need for point-of-care diagnostics. Critical shortages in reagents and testing kits have had a large impact on the ability to test patients with a suspected parasitic, bacteria, fungal, and viral infections. New point-of-care tests need to be highly sensitive, specific, and easy to use and provide results in rapid time. Infrared spectroscopy, coupled to multivariate and machine learning algorithms, has the potential to meet this unmet demand requiring minimal sample preparation to detect both pathogenic infectious agents and chronic disease markers in blood. This focal point article will highlight the application of Fourier transform infrared spectroscopy to detect disease markers in blood focusing principally on parasites, bacteria, viruses, cancer markers, and important analytes indicative of disease. Methodologies and state-of-the-art approaches will be reported and potential confounding variables in blood analysis identified. The article provides an up to date review of the literature on blood diagnosis using infrared spectroscopy highlighting the recent advances in this burgeoning field.

Predictors of postprandial glycaemia, insulinaemia and insulin resistance in adolescents

Postprandial glycaemia and insulinaemia are important risk factors for type 2 diabetes. The prevalence of insulin resistance in adolescents is increasing, but it is unknown how adolescent participant characteristics such as BMI, waist circumference, fitness and maturity offset may explain responses to a standard meal. The aim of the present study was to examine how such participant characteristics affect the postprandial glycaemic and insulinaemic responses to an ecologically valid mixed meal. Data from the control trials of three separate randomised, crossover experiments were pooled, resulting in a total of 108 participants (fifty-two boys, fifty-six girls; aged 12·5 (SD 0·6) years; BMI 19·05 (SD 2·66) kg/m2). A fasting blood sample was taken for the calculation of fasting insulin resistance, using the homoeostatic model assessment of insulin resistance (HOMA-IR). Further capillary blood samples were taken before and 30, 60 and 120 min after a standardised lunch, providing 1·5 g/kg body mass of carbohydrate, for the quantification of blood glucose and plasma insulin total AUC (tAUC). Hierarchical multiple linear regression demonstrated significant predictors for plasma insulin tAUC were waist circumference, physical fitness and HOMA-IR (F(3,98) = 36·78, P < 0·001, adjusted R2 = 0·515). The variance in blood glucose tAUC was not significantly explained by the predictors used (F(7,94) = 1·44, P = 0·198). Significant predictors for HOMA-IR were BMI and maturity offset (F(2,102) = 14·06, P < 0·001, adjusted R2 = 0·021). In summary, the key findings of the study are that waist circumference, followed by physical fitness, best explained the insulinaemic response to an ecologically valid standardised meal in adolescents. This has important behavioural consequences because these variables can be modified.

Phytochemical constituents, biological activities, and health-promoting effects of the genus Origanum

Origanum species are mostly distributed around the Mediterranean, Euro-Siberian, and Iran-Siberian regions. Since time immemorial, the genus has popularly been used in Southern Europe, as well as on the American continent as a spice now known all over the world under the name "oregano" or "pizza-spice." Origanum plants are also employed to prepare bitter tinctures, wines, vermouths, beer, and kvass. The major components of Origanum essential oil are various terpenes, phenols, phenolic acids, and flavonoids with predominant occurrence of carvacrol and thymol (with reasonable amounts of p-cymen and -terpinene) or of terpinene-4-ol, linalool, and sabinene hydrate. Many species of Origanum genus are used to treat kidney, digestive, nervous, and respiratory disorders, spasms, sore throat, diabetes, lean menstruation, hypertension, cold, insomnia, toothache, headache, epilepsy, urinary tract infections, etc. Origanum essential oil showed potent bioactivities owing to its major constituents' carvacrol, thymol, and monoterpenes. Several preclinical studies evidenced its pharmacological potential as antiproliferative or anticancer, antidiabetic, antihyperlipidemic, anti-obesity, renoprotective, antiinflammatory, vasoprotective, cardioprotective, antinociceptive, insecticidal, and hepatoprotective properties. Its nanotechnological applications as a promising pharmaceutical in order to enhance the solubility, physicochemical stability, and the accumulation rate of its essential oils have been investigated. However, Origanum has been reported causing angioedema, perioral dermatitis, allergic reaction, inhibition of platelet aggregation, hypoglycemia, and abortion. Conclusive evidences are still required for its clinical applications against human medical conditions. Toxicity analyses and risk assessment will aid to its safe and efficacious application. In addition, elaborate structure-activity studies are needed to explore the potential use of Origanum-derived phytochemicals as promising drug candidates.

Impaired glucose tolerance and future cardiovascular risk after coronary revascularization: a 10-year follow-up report

AIMS

Practical management guidelines for impaired glucose tolerance (IGT) have not been established. Although IGT is a potent marker of cardiovascular disease (CVD), it is still controversial whether its magnitude of CVD risk is comparable to that of frank diabetes. Moreover, information on long-term clinical outcomes of IGT patients undergoing coronary revascularization is limited. The aim of the present work was to investigate the 10-year prognostic impact of IGT in comparison with diabetes in patients with CAD undergoing coronary revascularization.

METHODS

This cohort recruited from two Japanese clinical sites included patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) between 2004 and 2008. Patients were categorized into previously known diabetes (PKD, n = 197), newly diagnosed diabetes (NDD, n = 51), and IGT (n = 50) groups according to oral glucose tolerance test results except for PKD. The primary end point was defined as a composite of cardiovascular death, myocardial infarction, stroke, repeat revascularization, and heart failure hospitalization.

RESULTS

The cumulative risk of the primary outcome was significantly higher in the PKD and IGT than in the NDD (log-rank test p = 0.017). A Cox proportional hazards model demonstrated that IGT (hazard ratio [HR], 7.91; 95% confidence interval [CI], 1.84-27.58) and creatinine clearance (HR, 7.89, 95% CI, 2.73-19.10) were predictors of long-term CVD risk, while NDD and PKD were not.

CONCLUSIONS

IGT significantly increased the long-term risk of developing CVD in patients with CAD after PCI compared with diabetes.

Short-acting insulin analogues versus regular human insulin for adult, non-pregnant persons with type 2 diabetes mellitus

BACKGROUND

The use of short-acting insulin analogues (insulin lispro, insulin aspart, insulin glulisine) for adult, non-pregnant people with type 2 diabetes is still controversial, as reflected in many scientific debates.

OBJECTIVES

To assess the effects of short-acting insulin analogues compared to regular human insulin in adult, non-pregnant people with type 2 diabetes mellitus.

SEARCH METHODS

For this update we searched CENTRAL, MEDLINE, Embase, the WHO ICTRP Search Portal, and ClinicalTrials.gov to 31 October 2018. We placed no restrictions on the language of publication.

SELECTION CRITERIA

We included all randomised controlled trials with an intervention duration of at least 24 weeks that compared short-acting insulin analogues to regular human insulin in the treatment of people with type 2 diabetes, who were not pregnant.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias. We assessed dichotomous outcomes by risk ratios (RR), and Peto odds ratios (POR), with 95% confidence intervals (CI). We assessed continuous outcomes by mean differences (MD) with 95% CI. We assessed trials for certainty of the evidence using the GRADE approach.

MAIN RESULTS

We identified 10 trials that fulfilled the inclusion criteria, randomising 2751 participants; 1388 participants were randomised to receive insulin analogues and 1363 participants to receive regular human insulin. The duration of the intervention ranged from 24 to 104 weeks, with a mean of about 41 weeks. The trial populations showed diversity in disease duration, and inclusion and exclusion criteria. None of the trials were blinded, so the risk of performance bias and detection bias, especially for subjective outcomes, such as hypoglycaemia, was high in nine of 10 trials from which we extracted data. Several trials showed inconsistencies in the reporting of methods and results.None of the included trials defined all-cause mortality as a primary outcome. Six trials provided Information on the number of participants who died during the trial, with five deaths out of 1272 participants (0.4%) in the insulin analogue groups and three deaths out of 1247 participants (0.2%) in the regular human insulin groups (Peto OR 1.66, 95% CI 0.41 to 6.64; P = 0.48; moderate-certainty evidence). Six trials, with 2509 participants, assessed severe hypoglycaemia differently, therefore, we could not summarise the results with a meta-analysis. Overall, the incidence of severe hypoglycaemic events was low, and none of the trials showed a clear difference between the two intervention arms (low-certainty evidence).The MD in glycosylated haemoglobin A1c (HbA1c) change was -0.03% (95% CI -0.16 to 0.09; P = 0.60; 9 trials, 2608 participants; low-certainty evidence). The 95% prediction ranged between -0.31% and 0.25%. The MD in the overall number of non-severe hypoglycaemic episodes per participant per month was 0.08 events (95% CI 0.00 to 0.16; P = 0.05; 7 trials, 2667 participants; very low-certainty evidence). The 95% prediction interval ranged between -0.03 and 0.19 events per participant per month. The results provided for nocturnal hypoglycaemic episodes were of questionable validity. Overall, there was no clear difference between the two short-acting insulin analogues and regular human insulin. Two trials assessed health-related quality of life and treatment satisfaction, but we considered the results for both outcomes to be unreliable (very low-certainty evidence).No trial was designed to investigate possible long term effects (all-cause mortality, microvascular or macrovascular complications of diabetes), especially in participants with diabetes-related complications. No trial reported on socioeconomic effects.

AUTHORS' CONCLUSIONS

Our analysis found no clear benefits of short-acting insulin analogues over regular human insulin in people with type 2 diabetes. Overall, the certainty of the evidence was poor and results on patient-relevant outcomes, like all-cause mortality, microvascular or macrovascular complications and severe hypoglycaemic episodes were sparse. Long-term efficacy and safety data are needed to draw conclusions about the effects of short-acting insulin analogues on patient-relevant outcomes.

Deep Multi-OMICs and Multi-Tissue Characterization in a Pre- and Postprandial State in Human Volunteers: The GEMM Family Study Research Design

Cardiovascular disease (CVD) and type 2 diabetes (T2D) are increasing worldwide. This is mainly due to an unhealthy nutrition, implying that variation in CVD risk may be due to variation in the capacity to manage a nutritional load. We examined the genomic basis of postprandial metabolism. Our main purpose was to introduce the GEMM Family Study (Genetics of Metabolic Diseases in Mexico) as a multi-center study carrying out an ongoing recruitment of healthy urban adults. Each participant received a mixed meal challenge and provided a 5-hours’ time course series of blood, buffy coat specimens for DNA isolation, and adipose tissue (ADT)/skeletal muscle (SKM) biopsies at fasting and 3 h after the meal. A comprehensive profiling, including metabolomic signatures in blood and transcriptomic and proteomic profiling in SKM and ADT, was performed to describe tendencies for variation in postprandial response. Our data generation methods showed preliminary trends indicating that by characterizing the dynamic properties of biomarkers with metabolic activity and analyzing multi-OMICS data it could be possible, with this methodology and research design, to identify early trends for molecular biology systems and genes involved in the fasted and fed states.

Sargassum sagamianum Extract Alleviates Postprandial Hyperglycemia in Diabetic Mice

In this study, we investigated the postprandial hypoglycemic effect of Sargassum sagamianum extract (SSE) in streptozotocin-induced diabetic mice. Freeze-dried S. sagamianum was extracted with 80% ethanol and concentrated. The inhibition of postprandial hyperglycemia was determined by the inhibitory activity against α-glucosidase and α-amylase as well as the measurement of postprandial blood glucose levels. SSE demonstrated a high inhibitory activity against α-glucosidase and α-amylase. The IC50 value of SSE against α-glucosidase and α-amylase was 0.095 mg/mL and 0.199 mg/mL, respectively, and thus it was significantly more efficacious than the pharmaceutical acarbose (0.115 mg/mL and 0.229 mg/mL, respectively). The postprandial blood glucose levels in the SSE-administered group were significantly lower than those in the control group. Furthermore, the area under the curve significantly decreased following the administration of SSE. These results indicate that SSE can be used as an α-glucosidase and α-amylase inhibitor and can delay the absorption of dietary carbohydrates.

Diabetes, plasma glucose and incidence of pancreatic cancer: A prospective study of 0.5 million Chinese adults and a meta-analysis of 22 cohort studies

Diabetes is associated with an increased risk of pancreatic cancer (PC) in Western populations. Uncertainty remains, however, about the relevance of plasma glucose for PC among people without diabetes and about the associations of diabetes and high blood glucose with PC in China where the increase in diabetes prevalence has been very recent. The prospective China Kadoorie Biobank (CKB) study recruited 512,000 adults aged 30‐79 years from 10 diverse areas of China during 2004‐2008, recording 595 PC cases during 8 years of follow‐up. Cox regression yielded adjusted hazard ratios (HRs) for PC associated with diabetes (previously diagnosed or screen‐detected) and, among those without previously diagnosed diabetes, with levels of random plasma glucose (RPG). These were further meta‐analysed with 22 published prospective studies. Overall 5.8% of CKB participants had diabetes at baseline. Diabetes was associated with almost twofold increased risk of PC (adjusted HR = 1.87, 95% CI 1.48‐2.37), with excess risk higher in those with longer duration since diagnosis (p for trend = 0.01). Among those without previously diagnosed diabetes, each 1 mmol/L higher usual RPG was associated with a HR of 1.12 (1.04‐1.21). In meta‐analysis of CKB and 22 other studies, previously diagnosed diabetes was associated with a 52% excess risk (1.52, 1.43‐1.63). Among those without diabetes, each 1 mmol/L higher blood glucose was associated with a 15% (1.15, 1.09‐1.21) excess risk. In Chinese and non‐Chinese populations, diabetes and higher blood glucose levels among those without diabetes are associated with an increased risk of PC.

What's new?

Diabetes is associated with increased risk of pancreatic cancer (PC) in Western populations, but uncertainty remains about the relevance of plasma glucose among people without diabetes. In this first prospective study investigating the association of diabetes with PC risk in China, where the increase in diabetes prevalence has been very recent, diabetes was associated with an almost twofold increased risk of PC, with random plasma glucose being positively associated with PC risk among participants without prior diagnosis of diabetes. In meta‐analysis, the results were consistent with previous evidence in Western populations, highlighting diabetes as a potential aetiological factor of PC.

Low-Level Environmental Lead Exposure and Dysglycemia in Adult Individuals: Results from the Canadian Health and Measure Survey 2007-2011

We aimed to evaluate the association of exposure to lead with glycated hemoglobin (HbA1c), fasting glucose levels (FGLs), and the likelihood for dysglycemia. We accessed data from Canada Health and Measures Survey. General linear models were used to estimate the association between blood lead concentrations (BPb) and both HbA1c and FGLs, while controlling for confounders. Multivariate logistic regression was used for assessing the relation between BPb and the likelihood for dysglycemia. FGLs in participants with moderate BPb (2.5-5.0 μg/dL) were 1.03 (95 % CI 1.00-1.06) times higher compared with participants with BPb < 2.5 μg/dL. Equivalent figures for those with BPb ≥ 5.0 μg/dL were 1.10 (95 % CI 1.01-1.20) times, relative to the lowest stratum. This association was attenuated using HbA1c to define dysglycemia. Lead exposure was associated with the likelihood for neither FGLs ≥ 1.10 g/L nor HbA1c ≥ 5.7 %. The association between lead exposure and dysglycemia, if any, is likely to be very modest, at least at the population level.

Review: Peripheral arterial disease in diabetes: time for a co-ordinated approach to management

Peripheral arterial disease (PAD) is a major manifestation of systemic atherosclerosis. A close association between PAD and diabetes mellitus has long been recognised. Substantial morbidity results from PAD-related intermittent claudication, ulceration and critical limb ischaemia, culminating for some patients in limb loss or death. While effective lifestyle and pharmacological treatments are available for intermittent claudication these approaches are widely underutilised. Surgical intervention is indicated in relatively few patients with stable intermittent claudication. However, the high risk of premature death from the consequences of generalised atherosclerosis, notably coronary heart disease, mandates identification and treatment of modifiable cardiovascular risk factors. Sub-optimal management of cardiovascular risk in patients with PAD may reflect disparate and poorly co-ordinated care. Among patients with diabetes, PAD poses additional dangers, arterial insufficiency being a major, and possibly underestimated, component of diabetic foot disease. The combination of PAD and diabetic neuropathy is common, particularly in the elderly, resulting in impaired infection control and delayed healing of foot ulcers. PAD may also cause ischaemic ulcers. The contribution of PAD to duration of hospitalisation and longer-term clinical outcomes remains uncertain. There appears to be scope for improving the efficiency of clinical care for patients with PAD. A co-ordinated multi-disciplinary approach is required to deliver optimal care to these patients. Modifiable cardiovascular risk factors should be identified and treated. Deficiencies in podiatry and related services in the UK need to be addressed.

Short-acting insulin analogues versus regular human insulin for adults with type 1 diabetes mellitus

BACKGROUND

Short-acting insulin analogue use for people with diabetes is still controversial, as reflected in many scientific debates.

OBJECTIVES

To assess the effects of short-acting insulin analogues versus regular human insulin in adults with type 1 diabetes.

SEARCH METHODS

We carried out the electronic searches through Ovid simultaneously searching the following databases: Ovid MEDLINE(R), Ovid MEDLINE(R) In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid OLDMEDLINE(R) (1946 to 14 April 2015), EMBASE (1988 to 2015, week 15), the Cochrane Central Register of Controlled Trials (CENTRAL; March 2015), ClinicalTrials.gov and the European (EU) Clinical Trials register (both March 2015).

SELECTION CRITERIA

We included all randomised controlled trials with an intervention duration of at least 24 weeks that compared short-acting insulin analogues with regular human insulins in the treatment of adults with type 1 diabetes who were not pregnant.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed trials for risk of bias, and resolved differences by consensus. We graded overall study quality using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) instrument. We used random-effects models for the main analyses and presented the results as odds ratios (OR) with 95% confidence intervals (CI) for dichotomous outcomes.

MAIN RESULTS

We identified nine trials that fulfilled the inclusion criteria including 2693 participants. The duration of interventions ranged from 24 to 52 weeks with a mean of about 37 weeks. The participants showed some diversity, mainly with regard to diabetes duration and inclusion/exclusion criteria. The majority of the trials were carried out in the 1990s and participants were recruited from Europe, North America, Africa and Asia. None of the trials was carried out in a blinded manner so that the risk of performance bias, especially for subjective outcomes such as hypoglycaemia, was present in all of the trials. Furthermore, several trials showed inconsistencies in the reporting of methods and results.The mean difference (MD) in glycosylated haemoglobin A1c (HbA1c) was -0.15% (95% CI -0.2% to -0.1%; P value < 0.00001; 2608 participants; 9 trials; low quality evidence) in favour of insulin analogues. The comparison of the risk of severe hypoglycaemia between the two treatment groups showed an OR of 0.89 (95% CI 0.71 to 1.12; P value = 0.31; 2459 participants; 7 trials; very low quality evidence). For overall hypoglycaemia, also taking into account mild forms of hypoglycaemia, the data were generally of low quality, but also did not indicate substantial group differences. Regarding nocturnal severe hypoglycaemic episodes, two trials reported statistically significant effects in favour of the insulin analogue, insulin aspart. However, due to inconsistent reporting in publications and trial reports, the validity of the result remains questionable.We also found no clear evidence for a substantial effect of insulin analogues on health-related quality of life. However, there were few results only based on subgroups of the trial populations. None of the trials reported substantial effects regarding weight gain or any other adverse events. No trial was designed to investigate possible long-term effects (such as all-cause mortality, diabetic complications), in particular in people with diabetes related complications.

AUTHORS' CONCLUSIONS

Our analysis suggests only a minor benefit of short-acting insulin analogues on blood glucose control in people with type 1 diabetes. To make conclusions about the effect of short acting insulin analogues on long-term patient-relevant outcomes, long-term efficacy and safety data are needed.

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.

Methylglyoxal in diabetes: link to treatment, glycaemic control and biomarkers of complications

Diabetic complications are major health problems worldwide, with the cost of caring for diabetes rising to US$245 billion in 2012 in the U.S.A. alone. It is widely recognized that non-enzymatic glycation in diabetes is a major cause of damage and dysfunction of key vascular cells. MG (methylglyoxal) is directly toxic to tissues, and is a major precursor of AGEs (advanced glycation end-products). Various propensities to diabetic complications are seen among individuals with diabetes, with accelerated rates occurring in some individuals with modest hyperglycaemia, while others never progress in spite of poor glycaemic control over many years. Since production and detoxification of MG is ultimately controlled by enzymatic mechanisms, both genetic and environmental factors could regulate tissue glycation and potentially account for these variable complication rates. Activation of pathways that determine MG levels occurs in susceptible patients, indicting an important role in pathogenesis. MG leads to formation of specific AGEs, which are likely to predict propensity to diabetic complications. We have shown recently that three specific plasma AGE biomarkers [MG-H1 (MG-derived hydroimidazolones), CEL (Nε-carboxyethyl-lysine) and CML (Nε-carboxymethyl-lysine)] predict biopsy-documented fast DN (diabetic nephropathy) progression. Since two of the predictive biomarkers are MG end-products, these outcomes support a role for MG in the development of DN. Our studies on MG and its end-products have also shown anti-complication effects of the drug metformin, which binds and inactivates MG, thus reducing MG-related AGEs. We have also shown that reducing post-meal glucose decreases MG levels, as well as levels of MG-related AGEs. Our clinical outcome studies have been based on the novel concept that the unique glycation products that we can measure reflect the activity of specific chemical pathways that are selectively activated by hyperglycaemia in patients that are inherently more susceptible to diabetic complications, and can be used to solve other diabetes-related medical questions.

Acute activation of cannabinoid receptors by anandamide reduces gastrointestinal motility and improves postprandial glycemia in mice

The endocannabinoid system (ECS) is associated with an alteration of glucose homeostasis dependent on cannabinoid receptor-1 (CB1R) activation. However, very little information is available concerning the consequences of ECS activation on intestinal glucose absorption. Mice were injected intraperitoneally with anandamide, an endocannabinoid binding both CB1R and CB2R. We measured plasma glucose and xylose appearance after oral loading, gastrointestinal motility, and glucose transepithelial transport using the everted sac method. Anandamide improved hyperglycemia after oral glucose charge whereas glucose clearance and insulin sensitivity were impaired, pointing out some gastrointestinal events. Plasma xylose appearance was delayed in association with a strong decrease in gastrointestinal transit, while anandamide did not alter transporter-mediated glucose absorption. Interestingly, transit was nearly normalized by coinjection of SR141716 and AM630 (CB1R and CB2R antagonist, respectively), and AM630 also reduced the delay of plasma glucose appearance induced by anandamide. When gastric emptying was bypassed by direct glucose administration in the duodenum, anandamide still reduced plasma glucose appearance in wild-type but not in CB1R(-/-) mice. In conclusion, our findings demonstrated that acute activation of intestinal ECS reduced postprandial glycemia independently on intestinal glucose transport but rather inhibiting gastric emptying and small intestine motility and strongly suggest the involvement of both CB1R and CB2R.

Effect of long-term supplementation of low molecular weight chitosan oligosaccharide (GO2KA1) on fasting blood glucose and HbA1c in db/db mice model and elucidation of mechanism of action

Background

Type 2 diabetes is a serious problem for developed countries. Prevention of prediabetes progression to type 2 diabetes with the use of natural products appears to a cost-effective solution. Previously we showed that enzymatically digested low molecular weight chitosan-oligosaccharide with molecular weight (MW) below 1,000 Da (GO2KA1) has potential for hyperglycemia management.

Methods

In this study we evaluated the effect of long-term supplementation of GO2KA1 on hyperglycemia using a db/db mice model. Additionally, we evaluated the effect of GO2KA1 on sucrase and glucoamylase activities and expression, using the same db/db mice model.

Results

After 42 days we observed that GO2KA1 supplementation reduced both the blood glucose level and HbA1c in a similar manner with a known anti-diabetic drug, acarbose. When the sucrase and glucoamylase activities of GO2KA1 and control mice were evaluated using enzymatic assay, we observed that GO2KA1 significantly inhibited sucrase in all 3 parts of the intestine, while glucoamylase activity was significantly reduced only in the middle and lower part. When the sucrase-isomaltase (SI) complex expression on mRNA level was evaluated, we observed that GO2KA1 had minimal inhibitory effect on the upper part, more pronounced inhibitory effect on the middle part, while the highest inhibition was observed on the lower part. Our findings suggest that long-term GO2KA1 supplementation in db/db mice results to significant blood glucose and HbA1c reduction, to levels similar with those of acarbose. Furthermore, our findings confirm previous in vitro observations that GO2KA1 has inhibitory effect on carbohydrate hydrolysis enzymes, namely sucrase, maltase and SI complex.

Conclusions

Results from this study provide a strong rationale for the use of GO2KA1 for type 2 diabetes prevention, via inhibition of carbohydrate hydrolysis enzymes. Based on the findings of this animal trial, clinical trials will be designed and pursued.

Role of endoplasmic reticulum stress in atherosclerosis and diabetic macrovascular complications

Age-related changes in endoplasmic reticulum (ER) are associated with stress of this cell organelle. Unfolded protein response (UPR) is a normal physiological reaction of a cell in order to prevent accumulation of unfolded and misfolded proteins in the ER and improve the normal ER function. However, in pathologic conditions such as atherosclerosis, obesity, and diabetes, ER function becomes impaired, leading to the development of ER stress. In chronic ER stress, defective posttranslational protein folding results in deposits of aberrantly folded proteins in the ER and the induction of cell apoptosis mediated by UPR sensors C/EBPα-homologous protein (CHOP) and inositol requiring protein-1 (IRE1). Since ER stress and ER-induced cell death play a nonredundant role in the pathogenesis of atherosclerosis and diabetic macrovascular complications, pharmaceutical targeting of ER stress components and pathways may be beneficial in the treatment and prevention of cardiovascular pathology.

Free Radicals Scavenging Capacity, Antidiabetic and Antihypertensive Activities of Flavonoid-Rich Fractions from Leaves of Trichilia emetica and Opilia amentacea in an Animal Model of Type 2 Diabetes Mellitus

Trichilia emetica and Opilia amentacea traditional Burkinabe medicinal plants were investigated to determine their therapeutic potential to inhibit key enzymes in carbohydrate metabolism, which has relevance to the management of type 2 diabetes. In vitro and in vivo antioxidant and antihypertensive potential and antilipidemia and antihyperglycemia activities in an animal model of type 2 diabetes mellitus have been studied. The antioxidant activity of the flavonoids from leaves of Trichilia emetica and Opilia amentacea has been evaluated using β -carotene-linoleic acid system, 1,1-diphenyl-2-picrylhydrazyl inhibitory activity, chelation of iron (II) ions, and lipid peroxidation which showed more pronounced antioxidant capacities of Trichilia emetica. Total cholesterol concentrations decreased in an animal model of type 2 diabetes mellitus under effects of flavonoid-rich fractions from leaves of Trichilia emetica and Opilia amentacea has been observed. Extract of flavonoid-rich fractions from Trichilia emetica shown maximum radical scavenging activity and possessed marked antiamylase activity which may be due to the presence of certain secondary metabolites. Suggested better antihyperglycemia, antilipidemia, and antihypertensive properties of flavonoid-rich fractions from Trichilia emetica compared to the extract of Opilia amentacea are demonstrating antidiabetic potential of Trichilia emetica as therapeutic targets for the management of type 2 diabetes.

Combined acute hyperglycemic and hyperinsulinemic clamp induced profibrotic and proinflammatory responses in the kidney

Increase in matrix protein content in the kidney is a cardinal feature of diabetic kidney disease. While renal matrix protein content is increased by chronic hyperglycemia, whether it is regulated by acute elevation of glucose and insulin has not been addressed. In this study, we aimed to evaluate whether short duration of combined hyperglycemia and hyperinsulinemia, mimicking the metabolic environment of prediabetes and early type 2 diabetes, induces kidney injury. Normal rats were subjected to either saline infusion (control, n = 4) or 7 h of combined hyperglycemic-hyperinsulinemic clamp (HG+HI clamp; n = 6). During the clamp, plasma glucose and plasma insulin were maintained at about 350 mg/dl and 16 ng/ml, respectively. HG+HI clamp increased the expression of renal cortical transforming growth factor-β (TGF-β) and renal matrix proteins, laminin and fibronectin. This was associated with the activation of SMAD3, Akt, mammalian target of rapamycin (mTOR) complexes, and ERK signaling pathways and their downstream target events in the initiation and elongation phases of mRNA translation, an important step in protein synthesis. Additionally, HG+HI clamp provoked renal inflammation as shown by the activation of Toll-like receptor 4 (TLR4) and infiltration of CD68-positive monocytes. Urinary F2t isoprostane excretion, an index of renal oxidant stress, was increased in the HG+HI clamp rats. We conclude that even a short duration of hyperglycemia and hyperinsulinemia contributes to activation of pathways that regulate matrix protein synthesis, inflammation, and oxidative stress in the kidney. This finding could have implications for the control of short-term rises in blood glucose in diabetic individuals at risk of developing kidney disease.

Impact of postprandial glycaemia on health and prevention of disease

Postprandial glucose, together with related hyperinsulinemia and lipidaemia, has been implicated in the development of chronic metabolic diseases like obesity, type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). In this review, available evidence is discussed on postprandial glucose in relation to body weight control, the development of oxidative stress, T2DM, and CVD and in maintaining optimal exercise and cognitive performance. There is mechanistic evidence linking postprandial glycaemia or glycaemic variability to the development of these conditions or in the impairment in cognitive and exercise performance. Nevertheless, postprandial glycaemia is interrelated with many other (risk) factors as well as to fasting glucose. In many studies, meal-related glycaemic response is not sufficiently characterized, or the methodology with respect to the description of food or meal composition, or the duration of the measurement of postprandial glycaemia is limited. It is evident that more randomized controlled dietary intervention trials using effective low vs. high glucose response diets are necessary in order to draw more definite conclusions on the role of postprandial glycaemia in relation to health and disease. Also of importance is the evaluation of the potential role of the time course of postprandial glycaemia.

Nonfasting glucose, ischemic heart disease, and myocardial infarction: a Mendelian randomization study

OBJECTIVES

The purpose of this study was to test whether elevated nonfasting glucose levels associate with and cause ischemic heart disease (IHD) and myocardial infarction (MI).

BACKGROUND

Elevated fasting plasma glucose levels associate with increased risk of IHD, but whether this is also true for nonfasting levels and whether this is a causal relationship is unknown.

METHODS

Using a Mendelian randomization approach, we studied 80,522 persons from Copenhagen, Denmark. Of those, IHD developed in 14,155, and MI developed in 6,257. Subjects were genotyped for variants in GCK (rs4607517), G6PC2 (rs560887), ADCY5 (rs11708067), DGKB (rs2191349), and ADRA2A (rs10885122) associated with elevated fasting glucose levels in genome-wide association studies.

RESULTS

Risk of IHD and MI increased stepwise with increasing nonfasting glucose levels. The hazard ratio for IHD in subjects with nonfasting glucose levels ≥11 mmol/l (≥198 mg/dl) versus <5 mmol/l (<90 mg/dl) was 6.9 (95% confidence interval [CI]: 4.2 to 11.2) adjusted for age and sex, and 2.3 (95% CI: 1.3 to 4.2) adjusted multifactorially; corresponding values for MI were 9.2 (95% CI: 4.6 to 18.2) and 4.8 (95% CI: 2.1 to 11.2). Increasing number of glucose-increasing alleles was associated with increasing nonfasting glucose levels and with increased risk of IHD and MI. The estimated causal odds ratio for IHD and MI by instrumental variable analysis for a 1-mmol/l (18-mg/dl) increase in nonfasting glucose levels due to genotypes combined were 1.25 (95% CI: 1.03 to 1.52) and 1.69 (95% CI: 1.28 to 2.23), and the corresponding observed hazard ratio for IHD and MI by Cox regression was 1.18 (95% CI: 1.15 to 1.22) and 1.09 (95% CI: 1.07 to 1.11), respectively.

CONCLUSIONS

Like common nonfasting glucose elevation, plasma glucose-increasing polymorphisms associate with increased risk of IHD and MI. These data are compatible with a causal association.

Postchallenge responses of nitrotyrosine and TNF-alpha during 75-g oral glucose tolerance test are associated with the presence of coronary artery diseases in patients with prediabetes

BACKGROUND

Meta-analysis has demonstrated an exponential relationship between 2-hr postchallenge hyperglycemia and coronary artery disease (CAD). Pulsatile hyperglycemia can acutely increase proinflammatory cytokines by oxidative stress. We hypothesized that postchallenge proinflammatory and nitrosative responses after 75 g oral glucose tolerance tests (75 g-OGTT) might be associated with CAD in patients without previously recognized type 2 diabetes mellitus (T2DM).

METHODS

Serial changes of plasma glucose (PG), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and nitrotyrosine levels were analyzed during 75 g-OGTT in 120 patients (81 male; age 62 ± 11 years) before coronary angiography. Patients were classified as normal (NGT; 42%), impaired (IGT; 34%) and diabetic (T2DM; 24%) glucose tolerance by 75 g-OGTT.

RESULTS

Postchallenge hyperglycemia elicited TNF-α, IL-6 and nitrotyrosine levels time-dependently, and 2-hr median levels of TNF-α (7.1 versus 6.4 pg/ml; P < 0.05) and nitrotyrosine (1.01 versus 0.83 μmol/l; P < 0.05), but not IL-6 or PG, were significantly higher in patients with CAD in either IGT or T2DM groups. After adjusting risk factors and glucose tolerance status, 2-hr nitrotyrosine in highest quartiles (OR: 3.1, P < 0.05) remained an independent predictor of CAD by logistic regression analysis.

CONCLUSIONS

These results highlight postchallenge proinflammatory and nitrosative responses by 75 g-OGTT, rather than hyperglycemia per se, are associated with CAD in patients without previous recognized diabetes.

The role of glucosamine-induced ER stress in diabetic atherogenesis

Cardiovascular disease (CVD) is the major cause of mortality in individuals with diabetes mellitus. However the molecular and cellular mechanisms that predispose individuals with diabetes to the development and progression of atherosclerosis, the underlying cause of most CVD, are not understood. This paper summarizes the current state of our knowledge of pathways and mechanisms that may link diabetes and hyperglycemia to atherogenesis. We highlight recent work from our lab, and others', that supports a role for ER stress in these processes. The continued investigation of existing pathways, linking hyperglycemia and diabetes mellitus to atherosclerosis, and the identification of novel mechanisms and targets will be important to the development of new and effective antiatherosclerotic therapies tailored to individuals with diabetes.

Physicochemical properties, in vitro antioxidant activities and inhibitory potential against α-glucosidase of polysaccharides from Ampelopsis grossedentata leaves and stems

In the present study, polysaccharides named ALPS and ASPS were isolated from Ampelopsis grossedentata leaves and stems, respectively. Physicochemical properties, in vitro antioxidant activities and the inhibitory effects on α-glucosidase of ALPS and ASPS were investigated. It was found that both ALPS and ASPS were acid protein-bound heteropolysaccharides, although with considerably different chemical composition and molecular weight distribution. Meanwhile, in comparison with ALPS, ASPS exhibited stronger antioxidant activity and inhibitory potential against α-glucosidase according to the in vitro evaluation. Moreover, our results suggested that protein and uronic acid might, at least partly, contribute positively to the biological behavior of ALPS and ASPS.

High glucose induced rat aorta vascular smooth muscle cell oxidative injury: involvement of protein tyrosine nitration

The alteration and further damage of vascular smooth muscle function have been implicated in the development of vascular complications and diabetes. Little is known about protein tyrosine nitration in vascular smooth muscle cell injury induced by high glucose. In this article, vascular smooth muscle cell was exposed to 30 and 40 mM high glucose for 72 h, and then the cell injury in vascular smooth muscle cell induced by high glucose was studied. It was found that high glucose stimulated vascular smooth muscle cell injury in a dose-dependent manner, including decreasing intracellular and extracellular glutathione contents, increasing malondialdehyde and intracellular reactive oxygen species content, increasing the production of nitric oxide (increased nitrite content in cell and medium), as well as increasing protein tyrosine nitration. By comparing protein tyrosine nitration induced by high glucose conditions and extrinsic factors (hemin-nitrite-glucose oxidase system and 3-morpholinosydnonimine), it may be speculated that protein is nitrated selectively, and specific protein tyrosine nitration is involved in diabetic vascular complications.

Microneedle-based intradermal versus subcutaneous administration of regular human insulin or insulin lispro: pharmacokinetics and postprandial glycemic excursions in patients with type 1 diabetes

BACKGROUND

This study assessed pharmacokinetics (PK) and pharmacodynamic postprandial glycemia (PPG) in patients with type 1 diabetes mellitus (T1DM) after a standardized liquid meal following insulin lispro (IL) or regular human insulin (RHI) given by microneedle-based intradermal (ID) versus subcutaneous (SC) delivery.

RESEARCH DESIGN AND METHODS

In this randomized, open-label, five-way crossover study, 29 T1DM patients received IL and RHI (0.125 U/kg) at 2 min and 17 min premeal, respectively, by both the SC and ID routes and also received RHI by the ID route at 2 min premeal. Blood glucose was stabilized at 120 mg/dL prior to a standardized 82-g carbohydrate liquid meal. ID delivery used a 34-gauge 1.5-mm steel microneedle, and SC delivery used a 31-gauge 8-mm syringe needle.

RESULTS

The 90-min PPG (blood glucose area under the curve for 0-1.5 h) for ID RHI was 14% lower than SC RHI at -17 min (P < 0.0001) and 11% lower than ID RHI at -2 min (P = 0.0006). PPG did not differ between ID RHI and SC IL, both at -2 min (P = 0.8345). ID IL PPG was lower than SC, both at -2 min, but not significantly (P = 0.10). Both ID IL and ID RHI PK data showed significantly faster uptake and time to maximum concentration, higher maximum concentration, and shorter systemic circulating duration versus SC dosing. ID IL and RHI delivery was generally well tolerated.

CONCLUSIONS

PPG with RHI administered ID via microneedle was improved versus SC delivery when dosed 17 min premeal. ID RHI provided similar control of PPG as SC IL immediately premeal. Further studies of ID insulin delivery via steel microneedles are warranted.

The cost effectiveness of rapid-acting insulin aspart compared with human insulin in type 2 diabetes patients: an analysis from the Japanese third-party payer perspective

OBJECTIVES

The Nippon Ultra-Rapid Insulin and Diabetic Complication Evaluation Study (NICE Study) (NCT00575172) was a 5-year, open-label, randomised controlled trial which compared cardiovascular outcomes in Japanese type 2 diabetes patients intensively treated with regular human insulin or insulin aspart (NovoRapid; Novo Nordisk A/S, Bagsvaerd, Denmark), a rapid-acting insulin analogue. The aim of the present analysis was to evaluate the cost effectiveness of insulin aspart versus regular human insulin from the perspective of a Japanese third-party healthcare payer.

RESEARCH DESIGN AND METHODS

A discrete event-simulation model was developed in Microsoft Excel to assess the within-trial cost effectiveness and make longer-term clinical projections in patients treated with regular human insulin or insulin aspart. In addition to severe hypoglycaemia, the model captured myocardial and cerebral infarction events and percutaneous coronary intervention and coronary artery bypass graft procedures. Within-trial mortality, incidence of severe hypoglycaemia and cardiovascular event probabilities were derived from the annual rates observed during the trial period, while post-trial outcomes were calculated using the event rates from the trial, adjusted for increasing patient age. Event costs were accounted from the healthcare payer perspective and expressed in 2008 Japanese yen (JPY), while health-related quality of life (HRQoL) was captured using event and state utilities. Future costs and clinical benefits were discounted at 3% annually. Life expectancy, quality-adjusted life expectancy, cardiovascular event rates and costs were evaluated over 5- and 10-year time horizons and sensitivity analyses were performed to assess variability in model outcomes.

RESULTS

Over 5 years of treatment, insulin aspart dominated human insulin both in incremental life expectancy and in incremental quality-adjusted life-years (QALYS). Insulin aspart was associated with a small improvement in discounted life expectancy of 0.005 years (4.688 vs. 4.684 years) and an increase of 0.023 quality-adjusted life-years (QALYs) (3.800 vs. 3.776 QALYs) when compared with regular human insulin. Insulin aspart also incurred lower costs (JPY 481,586 vs. 594,717, difference -113,131) which resulted from the decreased incidence of cardiovascular events with insulin aspart (0.013 events per patient year vs. 0.030 on regular human insulin). Breakdown of costs indicated that pharmacy costs were higher with insulin aspart (JPY 346,608 vs. 278,468), but these costs were more than offset by the reduced costs associated with cardiovascular complications and hypoglycaemia over 5 years of treatment (JPY 134,978 vs. 316,249). Sensitivity analysis showed that insulin aspart was still cost-effective in the case where only 18% of the within-trial cardiovascular and mortality benefit over regular human insulin was captured in the model (assuming a willingness-to-pay threshold of JPY 5,000,000).

LIMITATIONS

The NICE study cohort was relatively small (n = 325), meaning that caution should be exercised when calculating and interpreting the incremental cost-effectiveness ratio. Also, despite the differences in cardiovascular risk profile between the Japanese and UK populations, UKPDS-derived risk equations were used to project MI outcomes and PCI and CABG procedures and UKPDS HRQoL scores were applied to all health states. While these risk formulas and HRQoL utilities may not be directly applicable to the Japanese population, no equivalent Japanese-specific data are currently available.

CONCLUSIONS

In a Japanese type 2 diabetes population, prescribing rapid-acting insulin aspart significantly reduced cardiovascular complications over 5- and 10-year time horizons, resulting in increased quality of life and decreased costs when compared with human insulin.

Combined use of fasting plasma glucose and glycated hemoglobin A1c in the screening of diabetes and impaired glucose tolerance

The aim of this study is to assess the validity of combined use of fasting plasma glucose (FPG) and glycated hemoglobin A1c (HbA1c) as screening tests for diabetes and impaired glucose tolerance (IGT) in high-risk subjects. A total of 2,298 subjects were included. All subjects underwent a 75-g oral glucose tolerance test (OGTT) and HbA1c measurement. Receiver operating characteristic curve (ROC curve) analysis was used to examine the sensitivity and specificity of FPG and HbA1c for detecting diabetes and IGT, which was defined according to the 1999 World Health Organization (WHO) criteria. (1) Based on the ROC curve, the optimal cut point of FPG related to diabetes diagnosed by OGTT was 6.1 mmol/l that was associated with a sensitivity and specificity of 81.5 and 81.0%, respectively; The optimal cut point of HbA1c related to diabetes diagnosed by OGTT was 6.1%, which was associated with a sensitivity and specificity of 81.0 and 81.0%, respectively; The screening model using FPG > or = 6.1 mmol/l or HbA1c > or = 6.1% had sensitivity of 96.5% for detecting undiagnosed diabetes; the screening model using FPG > or = 6.1 mmol/l and HbA1c > or = 6.1% had specificity of 96.3% for detecting undiagnosed diabetes. (2) Based on the ROC curve, the optimal cut point of FPG related to IGT diagnosed by OGTT was 5.6 mmol/l that was associated with a sensitivity and specificity of 64.1 and 65.4%, respectively; The optimal cut point of HbA1c related to IGT diagnosed by OGTT was 5.6%, which was associated with a sensitivity and specificity of 66.2 and 51.0%, respectively; The screening model using FPG > or = 5.6 mmol/l or HbA1c > or = 5.6% had sensitivity of 87.9% for detecting undiagnosed IGT; The screening model using FPG > or = 5.6 mmol/l and HbA1c > or = 5.6% had specificity of 82.4% for detecting undiagnosed IGT. Compared with FPG or HbA1c alone, the simultaneous measurement of FPG and HbA1c (FPG and/or HbA1C) might be a more sensitive and specific screening tool for identifying high-risk individuals with diabetes and IGT at an early stage.

In vitro potential of Ascophyllum nodosum phenolic antioxidant-mediated alpha-glucosidase and alpha-amylase inhibition

Ascophyllum nodosum is a brown seaweed that grows abundantly in the Northeast coastal region. In this study, the potential of A. nodosum for type 2 diabetes management through antioxidant-mediated alpha-glucosidase and alpha-amylase inhibition was investigated. After the initial screening of 4 locally harvested seaweeds, A. nodosum was chosen for its highest phenolic content and was subjected to water extraction. Among extraction ratios of 50 g to 100 to 1000 mL at room temperature, 50 g/400 mL yielded the highest phenolic content of 4.5 mg/g wet weight. For evaluation of extraction temperature ranging from 20 to 80 degrees C, 50 g/400 mL was chosen as a minimum amount of extractant. Among temperatures studied, extraction at 80 degrees C resulted in the highest total phenolic contents (4.2 mg/g wet weight). All extracts had similar levels of antioxidant activity in the range of 60% to 70% in terms of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The 80 degrees C extract had the highest alpha-glucosidase and alpha-amylase inhibitory activity with IC(50) of 0.24 and 1.34 microg phenolics, respectively, compared to the IC(50) of acarbose, reference inhibitor, being 0.37 and 0.68 microg. The results show that fresh A. nodosum has strong alpha-glucosidase and mild alpha-amylase inhibitory activities that correlated with phenolic contents. This study suggests a nutraceutical potential of A. nodosum based on phytochemical antioxidant and antihyperglycemia activities.

Insulin-dependent diabetes mellitus in mice does not alter liver heparan sulfate

Diabetes -associated hyperlipidemia is generally attributed to reduced clearance of plasma lipoproteins, especially remnant lipoproteins enriched in cholesterol and triglycerides. Hepatic clearance of remnants occurs via low density lipoprotein receptors and the heparan sulfate proteoglycan, syndecan-1. Previous studies have suggested alterations in heparan sulfate proteoglycan metabolism in rat and mouse diabetic models, consistent with the idea that diabetic dyslipidemia might be caused by alterations in proteoglycan expression in the liver. In this study we analyzed the content and composition of liver heparan sulfate in streptozotocin-induced insulin-deficient diabetic mice that displayed fasting hypertriglyceridemia and delayed clearance of dietary triglyceride-rich lipoproteins. No differences between normal and diabetic littermates in liver heparan sulfate content, sulfation, syndecan-1 protein levels, or affinity for heparin-binding ligands, such as apolipoprotein E or fibroblast growth factor-2, were noted. Decreased incorporation of [(35)S]sulfate in insulin-deficient mice in vivo was observed, but the decrease was due to increased plasma inorganic sulfate, which reduced the efficiency of labeling of liver heparan sulfate. These results show that hyperlipidemia in insulin-deficient mice is not due to changes in hepatic heparan sulfate composition.

Glucose homeostasis abnormalities in cardiac intensive care unit patients

The aim of this study was to characterize the abnormalities in glucose homeostasis in intensive care unit patients following an acute coronary event. The study population included all non-diabetic patients ages 20-80 years that were admitted to a coronary intensive unit. Glucose, insulin and C-peptide levels during an oral glucose tolerance test (OGTT) were measured during the acute admission. From January to September 2003, 277 patients were admitted to the coronary unit. Of these, 127 patients underwent an OGTT. Of these, only 29 patients (23%) exhibited normal glucose metabolism. The remainder had type 2 diabetes (32%), impaired glucose tolerance (37%) or isolated impaired fasting glucose (8%, 100-125 mg/dl). Based on homeostasis model assessment (HOMA) calculations, diabetic patients had impaired beta-cell function and patients with elevated fasting glucose levels were insulin resistant. Beta-cell dysfunction during the acute stress seems to contribute to the glucose abnormalities. Most patients who experience an acute coronary event demonstrate abnormal glucose metabolism. Post glucose-load abnormalities are more common than abnormal fasting glucose level in this situation. It is postulated that the acute stress of a coronary event may contribute to the dysglycemia.

The second-meal phenomenon is associated with enhanced muscle glycogen storage in humans

The rise in blood glucose after lunch is less if breakfast has been eaten. The metabolic basis of this second-meal phenomenon remains uncertain. We hypothesized that storage of ingested glucose as glycogen could be responsible during the post-meal suppression of plasma NEFAs (non-esterified fatty acids; 'free' fatty acids). In the present study we determined the metabolic basis of the second-meal phenomenon. Healthy subjects were studied on two separate days, with breakfast and without breakfast in a random order. We studied metabolic changes after a standardized test lunch labelled with 3 g of 13C-labelled (99%) glucose. Changes in post-prandial muscle glycogen storage were measured using 13C magnetic resonance spectroscopy. The rise in plasma glucose after lunch was significantly less if breakfast had been taken (0.9+/-0.3 compared with 3.2+/-0.3 mmol/l, with and without breakfast respectively; P<0.001), despite comparable insulin responses. Pre-lunch NEFAs were suppressed after breakfast (0.13+/-0.03 compared with 0.51+/-0.04 mmol/l) and levels correlated positively with the maximum glucose rise after lunch (r=0.62, P=0.001). The increase in muscle glycogen signal was greater 5 h after lunch on the breakfast day (103+/-21 compared with 48+/-12 units; P<0.007) and correlated negatively with plasma NEFA concentrations before lunch (r=-0.48, P<0.05). The second-meal effect is associated with priming of muscle glycogen synthesis consequent upon sustained suppression of plasma NEFA concentrations.

Changes in insulin sensitivity and insulin release in relation to glycemia and glucose tolerance in 6,414 Finnish men

OBJECTIVE

We evaluated insulin sensitivity and insulin secretion across the entire range of fasting (FPG) and 2-h plasma glucose (PG), and we investigated the differences in insulin sensitivity and insulin release in different glucose tolerance categories.

RESEARCH DESIGN AND METHODS

A total of 6,414 Finnish men (aged 57 +/- 7 years, BMI 27.0 +/- 3.9 kg/m2) from our ongoing population-based METSIM (Metabolic Syndrome in Men) study were included. Of these subjects, 2,168 had normal glucose tolerance, 2,859 isolated impaired fasting glucose (IFG), 217 isolated impaired glucose tolerance (IGT), 701 a combination of IFG and IGT, and 469 newly diagnosed type 2 diabetes.

RESULTS

The Matsuda index of insulin sensitivity decreased substantially within the normal range of FPG (-17%) and 2-h PG (-37%) and was approximately -65 and -53% in the diabetic range of FPG and 2-h PG, respectively, compared with the reference range (FPG and 2-h PG <5.0 mmol/l). Early-phase insulin release declined by only approximately -5% within the normal range of FPG and 2-h PG but decreased significantly in the diabetic range of FPG (by 32-70%) and 2-h PG (by 33-51%). Changes in insulin sensitivity and insulin secretion in relation to hyperglycemia were independent of obesity. The predominant feature of isolated IGT was impaired peripheral insulin sensitivity. Isolated IFG was characterized by impaired early and total insulin release.

CONCLUSIONS

Peripheral insulin sensitivity was already decreased substantially at low PG levels within the normoglycemic range, whereas impairment in insulin secretion was observed mainly in the diabetic range of FPG and 2-h PG. Obesity did not affect changes in insulin sensitivity or insulin secretion in relation to hyperglycemia.

Association of impaired fasting glucose and coronary artery calcification as a marker of subclinical atherosclerosis in a population-based cohort--results of the Heinz Nixdorf Recall Study

AIMS/HYPOTHESIS

Atherosclerosis and cardiovascular diseases are often present at the time of diagnosis of type 2 diabetes mellitus. Whether subclinical atherosclerosis can be detected in the pre-diabetic (borderline fasting hyperglycemia) state is not clear. This study investigated the association of impaired fasting glucose (IFG) and coronary artery calcification (CAC), a marker of subclinical atherosclerosis, among participants without a history of coronary heart disease or manifest diabetes mellitus.

METHODS

Study participants (aged 45-75 years) of the population-based Heinz Nixdorf Recall Study were categorised into those with normal fasting glucose (glucose <6.1 mmol/l) and those with IFG (glucose >or=6.1 to <7.0 mmol/l), excluding participants with a history of CHD or diabetes mellitus. CAC was assessed by electron-beam computed tomography, and risk factors were assessed by extended interviews, anthropometric measurements and laboratory tests. Various CAC cut-off points were used in multiple logistic and ordinal logistic regression models to estimate ORs and 95% CIs.

RESULTS

Of the 2,184 participants, more men had IFG than did women (37% vs 22%). Participants with IFG showed a higher prevalence of CAC > 0 (men OR 1.90, 95% CI 1.33-2.70; women 1.63, 1.23-2.15). Risk factor adjustment weakened this association in both sexes (men 1.63, 1.12-1.36; women 1.26, 0.93-1.70). When the age- and sex-specific 75th percentile was used as the cut-off point for CAC, the association further decreased in men (1.10, 0.81-1.50), but became stronger in women (1.41, 1.02-1.94).

CONCLUSIONS/INTERPRETATION

These data support the hypothesis that CAC is already present in the pre-diabetic state and that IFG has a modest and independent impact on the atherosclerotic process. Biological sex appears to modify the association between IFG and CAC.

Defining the role of insulin lispro in the management of postprandial hyperglycaemia in patients with type 2 diabetes mellitus

The role of postprandial hyperglycaemia in contributing to the risk of both micro- and macrovascular complications in patients with diabetes mellitus is being increasingly recognized. In type 2 diabetes, there is a progressive shift in the relative contributions of postprandial and fasting hyperglycaemia to the overall glycaemic control as the disease progresses. For patients with fairly good glycaemic control (glycosylated haemoglobin [HbA(1c)] <8.5%), postprandial hyperglycaemia makes a relatively greater contribution to the overall glycaemic load than fasting hyperglycaemia, but in patients with poorer control, the relative contribution of the two states to the overall glycaemic load is reversed. This finding, coupled with epidemiological evidence that elevated postprandial glucose concentration is an independent risk factor for cardiovascular disease (CVD), and is associated with a greater CVD risk than elevated fasting glucose, points to the need to monitor and target postprandial glucose, as well as fasting glucose and HbA(1c) levels, when optimizing insulin therapy for patients with type 2 diabetes. When insulin therapy becomes necessary in patients with type 2 diabetes who can no longer be controlled with oral antihyperglycaemic therapy, use of short-acting insulin analogues with a rapid onset of action and capable of controlling postprandial glycaemic excursions when injected immediately before a meal, has advantages over regular human insulin in that they provide a more favourable time-action profile that mimics normal physiological insulin secretion. Among the available rapid-acting insulin analogues, insulin lispro has been shown to reduce postprandial glucose concentrations to a significantly greater degree than regular human insulin in patients with type 2 diabetes. Moreover, premixed combinations of insulin lispro with the longer acting analogue neutral insulin lispro protamine suspension in 25% : 75% or 50% : 50% combinations are significantly more effective in lowering postprandial blood glucose concentrations than premixed regular human insulin plus neutral protamine Hagedorn (NPH) 30% : 70%. The premixed insulin lispro combinations offer the advantage of fewer daily injections than intensive insulin therapy, and the convenience of not having to mix insulin preparations manually. Although it has yet to be conclusively established that targeting postprandial hyperglycaemia reduces CVD risk, the potential benefits of improved postprandial and interprandial hyperglycaemia favour the use of newer insulin analogues, such as insulin lispro and insulin lispro mixes, over conventional insulin therapy, whenever insulin therapy becomes necessary in patients with type 2 diabetes.

In vitro studies of eggplant (Solanum melongena) phenolics as inhibitors of key enzymes relevant for type 2 diabetes and hypertension

National Diabetes Education Program of NIH, Mayo Clinic and American Diabetes Association recommend eggplant-based diet as a choice for management of type 2 diabetes. The rationale for this suggestion is the high fiber and low soluble carbohydrate content of eggplant. We propose that a more physiologically relevant explanation lies in the phenolic-linked antioxidant activity and alpha-glucosidase inhibitory potential of eggplant which could reduce hyperglycemia-induced pathogenesis. Results from this study indicate that phenolic-enriched extracts of eggplant with moderate free radical scavenging-linked antioxidant activity had high alpha-glucosidase inhibitory activity and in specific cases moderate to high angiotensin I-converting enzyme (ACE) inhibitory activity. Inhibition of these enzymes provide a strong biochemical basis for management of type 2 diabetes by controlling glucose absorption and reducing associated hypertension, respectively. This phenolic antioxidant-enriched dietary strategy also has the potential to reduce hyperglycemia-induced pathogenesis linked to cellular oxidation stress. These results provide strong rationale for further animal and clinical studies.

Improvement of postprandial lipid handling and glucose tolerance in a non-diabetic population by the dual PPARalpha/gamma agonist, tesaglitazar

This study examined the effect of tesaglitazar (GALIDA), a dual peroxisome proliferator-activated receptor (PPAR)alpha/gamma agonist, on postprandial metabolism. This investigation was part of the Study in Insulin Resistance (SIR) (SH-SBT-0001), a randomised, double-blind, placebo-controlled study that reported improvements in fasting lipid and glucose values with tesaglitazar (0.1, 0.25, 0.5 or 1 mg once daily for 12 weeks) in hypertriglyceridaemic, abdominally obese, non-diabetic patients. A subgroup of 222 patients underwent postprandial lipid and glucose testing at baseline and treatment end. Tesaglitazar 0.25, 0.5 and 1 mg reduced postprandial area under the curve (AUC) for triglycerides by 20% (p=0.003), 30% (p<0.0001) and 41% (p<0.0001), respectively. Free fatty acid (FFA) levels were reduced by 17% with tesaglitazar 0.5 mg (p=0.002) and by 29% with tesaglitazar 1 mg (p<0.0001). Tesaglitazar significantly improved glucose tolerance and increased the proportion of patients with normal glucose tolerance as measured by the oral glucose tolerance test (OGTT). To conclude, postprandial dyslipidaemia and hyperglycaemia, indicators of increased vascular risk, were significantly improved by tesaglitazar treatment in these non-diabetic, hypertriglyceridaemic, abdominally obese subjects.

Cardiovascular actions of insulin

Insulin has important vascular actions to stimulate production of nitric oxide from endothelium. This leads to capillary recruitment, vasodilation, increased blood flow, and subsequent augmentation of glucose disposal in classical insulin target tissues (e.g., skeletal muscle). Phosphatidylinositol 3-kinase-dependent insulin-signaling pathways regulating endothelial production of nitric oxide share striking parallels with metabolic insulin-signaling pathways. Distinct MAPK-dependent insulin-signaling pathways (largely unrelated to metabolic actions of insulin) regulate secretion of the vasoconstrictor endothelin-1 from endothelium. These and other cardiovascular actions of insulin contribute to coupling metabolic and hemodynamic homeostasis under healthy conditions. Cardiovascular diseases are the leading cause of morbidity and mortality in insulin-resistant individuals. Insulin resistance is typically defined as decreased sensitivity and/or responsiveness to metabolic actions of insulin. This cardinal feature of diabetes, obesity, and dyslipidemia is also a prominent component of hypertension, coronary heart disease, and atherosclerosis that are all characterized by endothelial dysfunction. Conversely, endothelial dysfunction is often present in metabolic diseases. Insulin resistance is characterized by pathway-specific impairment in phosphatidylinositol 3-kinase-dependent signaling that in vascular endothelium contributes to a reciprocal relationship between insulin resistance and endothelial dysfunction. The clinical relevance of this coupling is highlighted by the findings that specific therapeutic interventions targeting insulin resistance often also ameliorate endothelial dysfunction (and vice versa). In this review, we discuss molecular mechanisms underlying cardiovascular actions of insulin, the reciprocal relationships between insulin resistance and endothelial dysfunction, and implications for developing beneficial therapeutic strategies that simultaneously target metabolic and cardiovascular diseases.

Effect of simulated postprandial hyperglycemia on coronary blood flow in cardiac transplant recipients

Patients with diabetes mellitus exhibit postprandial hyperglycemia, systemic oxidative stress, impaired endothelium-dependent, nitric oxide (NO)-mediated coronary artery dilatation, and an increased incidence of coronary events. Whether hyperglycemia causally mediates these associations is unknown. To test the hypothesis that postprandial hyperglycemia acutely impairs coronary endothelial function in humans, we compared the ability of the endothelium-dependent vasodilator acetylcholine to increase conduit coronary diameter (the macrovascular response) and coronary blood flow velocity (the microvascular response) in 12 cardiac transplant recipients without diabetes before and after blood glucose was raised from 6.7 ± 1.3 mmol/l (121 ± 24 mg/dl) to 17.8 ± 1.5 mmol/l (321 ± 27 mg/dl) for 1 h. Hyperglycemia acutely doubled circulating levels of the oxidation product malondialdehyde, indicating systemic oxidative stress, but did not affect the ability of acetylcholine to dilate conduit coronary segments or accelerate coronary blood flow. We conclude that the oxidative stress associated with a single acute episode of hyperglycemia affects neither acetylcholine-mediated coronary endothelial NO release nor the subsequent bioavailability, metabolism, or action of NO within the coronary circulation of cardiac transplant recipients. These observations imply that the relationship among hyperglycemia, oxidative stress, and coronary endothelial dysfunction is presumably mediated by mechanisms operating over longer periods of time.

Prevention of cardiovascular disease in persons with type 2 diabetes mellitus: current knowledge and rationale for the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial

Patients with type 2 diabetes mellitus die of cardiovascular disease (CVD) at rates 2-4 times higher than patients without diabetes but with similar demographic characteristics. The prevalence of diabetes is increasing in the United States and, thus, the prevention of CVD in patients with diabetes poses an urgent public health challenge. The objective of this report is to review the current knowledge base for the prevention of CVD in patients with diabetes, with particular emphasis on the control of glycemia, lipids, and blood pressure. Epidemiologic analyses suggest that each 1% increase in glycosylated hemoglobin increases the risk for CVD by approximately 18%; however, evidence from the randomized trials that have examined whether glucose lowering reduces this risk is conflicting. Randomized trials have shown that lowering low-density lipoprotein cholesterol reduces CVD event rates by 17%-43% in patients with diabetes. Limited data support a role for lowering triglycerides and increasing high-density lipoprotein cholesterol in the prevention of CVD. Evidence from clinical trials shows that reducing systolic blood pressure to <140 mm Hg results in 30%-60% reductions in CVD events; however, epidemiologic evidence suggests that lowering to optimal systolic blood pressure levels (<120 mm Hg) may be additionally beneficial. Important questions regarding prevention of CVD in patients with diabetes remain unresolved, including the benefits of near-normal glycemic control, comprehensive therapy for diabetes-related dyslipidemia, and optimal blood pressure control. The Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial will test hypotheses to address these unanswered questions.

Effect of pioglitazone on the metabolic and hormonal response to a mixed meal in type II diabetes

We explored the mechanisms by which a 4-month, placebo-controlled pioglitazone treatment (45 mg/day) improves glycemic control in type II diabetic patients (T2D, n=27) using physiological testing (6-h mixed meal) and a triple tracer technique ([6,6-(2)H(2)]glucose infusion, (2)H(2)O and [6-(3)H]glucose ingestion) to measure endogenous glucose production (EGP), gluconeogenesis (GNG), insulin-mediated glucose clearance and beta-cell glucose sensitivity (by c-peptide modeling). Compared to sex/age/weight-matched non-diabetic controls, T2D patients showed inappropriately (for prevailing insulinemia) raised glucose production (1.05[0.53] vs 0.71[0.36]mmol min(-1) kg(ffm)(-1) pM, P=0.03) because of enhanced GNG (73.1+/-2.4 vs 59.5+/-3.6%, P<0.01) persisting throughout the meal, reduced insulin-mediated glucose clearance (6[5] vs 12[13]ml min(-1) kg(ffm)(-1) nM(-1), P<0.005), and impaired beta-cell glucose-sensitivity (27[38] vs 71[37]pmol min(-1) m(-2) mM(-1), P=0.002). Compared to placebo, pioglitazone improved glucose overproduction (P=0.0001), GNG and glucose underutilization (P=0.05) despite lower insulinemia. GNG improvement was quantitatively related to raised adiponectin. beta-cell glucose sensitivity was unchanged. In mild-to-moderate T2D, pioglitazone monotherapy decreased fasting and post-prandial glycemia, principally via inhibition of gluconeogenesis, improved hepatic and peripheral insulin resistance.

Insulin glargine in combination with nateglinide in people with Type 2 diabetes: a randomized placebo-controlled trial

OBJECTIVE

To determine the effect of adding nateglinide to therapy with insulin glargine in adults with Type 2 diabetes previously treated with insulin and with poor blood glucose control.

RESEARCH DESIGN AND METHODS

In this 16-week, double-blind, placebo-controlled study, people with Type 2 diabetes [n = 55, HbA(1c) 8.2 +/- 1.0 (+/- sd)%, duration of diabetes 12.8 +/- 6.0 years, duration of insulin treatment 6.0 +/- 4.0 years] were transferred to single bedtime injection of insulin glargine for a titration period of 4 weeks, and then randomized to nateglinide or matching placebo before meals in addition to insulin glargine. Metformin was continued if taken. Doses of insulin and oral medication were titrated to protocol for the treatment period of 12 weeks.

RESULTS

Baseline-adjusted self-monitored capillary blood glucose concentration at 12 weeks was significantly lower with nateglinide + insulin glargine compared with placebo + insulin glargine after breakfast [difference -2.3 (95% confidence interval -4.4, -0.2) mmol/l, P = 0.030], before lunch [-2.5 (-4.6, -0.3) mmol/l, P = 0.029], and after lunch [-2.3 (-4.3, -0.4) mmol/l, P = 0.021], but not at other times. Baseline-adjusted HbA(1c) was not lower with nateglinide + insulin glargine as compared with placebo + insulin glargine [7.8 +/- 1.4 vs. 8.3 +/- 1.0%, difference -0.43 (-0.98, 0.12)%].

CONCLUSIONS

Addition of nateglinide before meals to once-daily insulin glargine in people with long-standing diabetes already requiring insulin therapy improves blood glucose control in the early part of the day after breakfast and lunch, but does not provide good control of blood glucose levels overall.

Tumor suppressor BRCA1 inhibits a breast cancer-associated promoter of the aromatase gene (CYP19) in human adipose stromal cells

Adipose tissue provides an important extragonadal source of estrogen. Obesity-associated elevation of estrogen production increases risk of breast cancer in postmenopausal women. Aromatase (CYP19), which converts androgen to estrogen, is a key enzyme in estrogen biosynthesis. In normal adipose tissue, transcription of the aromatase gene is initiated from a relatively weak adipose-specific promoter (I.4). However, in breast cancer, a switch of promoter utilization from I.4 to a strong ovary-specific promoter, PII, leads to increased aromatase expression and, hence, elevated estrogen production. Here, we report an intriguing relationship between the breast cancer susceptibility gene BRCA1 and aromatase expression in human adipose stromal cells (ASCs). Upon stimulation by phorbol ester or dexamethasone, increased aromatase expression in ASCs was accompanied by significant reduction of the BRCA1 level. In addition, adipogenesis-induced aromatase expression was also inversely correlated with BRCA1 abundance. Downregulation of BRCA1 expression in response to various stimuli was through distinct transcription or posttranscription mechanisms. Importantly, siRNA-mediated knockdown of BRCA1 led to specific activation of the breast cancer-associated PII promoter. Therefore, in addition to its well-characterized activities in breast epithelial cells, a role of BRCA1 in modulation of estrogen biosynthesis in ASCs may also contribute to its tissue-specific tumor suppressor function.

Prevalence and correlates of post-prandial hyperglycaemia in a large sample of patients with type 2 diabetes mellitus

AIMS/HYPOTHESIS

Post-prandial glucose may be a risk factor for cardiovascular disease and chronic diabetic complications. We tested the hypothesis that post-prandial hyperglycaemia is common in type 2 diabetes, even among patients in apparently good glycaemic control, and that simple clinical characteristics identify subsets of diabetic patients with frequent post-prandial hyperglycaemia.

SUBJECTS AND METHODS

Three self-assessed daily blood glucose profiles over a 1-week period, including 18 glucose readings before and 2 h after meals, were obtained from 3,284 unselected outpatients (men 51%; age 63+/-10 years) with non-insulin-treated type 2 diabetes mellitus attending 500 different diabetes clinics operating throughout Italy.

RESULTS

A post-prandial blood glucose value >8.89 mmol/l (160 mg/dl) was recorded at least once in 84% of patients, and 81% of patients had at least one Delta glucose > or =2.22 mmol/l (40 mg/dl). Among patients with apparently good metabolic control, 38% had >40% of post-prandial blood glucose readings >8.89 mmol/l (> or =4 of 9 meals in total), and 36% had >40% Delta glucose > or =2.22 mmol/l. In multivariate analysis adjusted for pre-prandial glucose levels, older age, longer duration of diabetes, absence of obesity, hyperlipidaemia and hypertension, as well as treatment with sulfonylureas, were significantly associated with greater glucose excursions after meals.

CONCLUSIONS/INTERPRETATION

These results indicate that post-prandial hyperglycaemia is a very frequent phenomenon in patients with type 2 diabetes mellitus on active treatment; can occur even when metabolic control is apparently good; and can be predicted by simple clinical features.