Older adults' decision-making following bad advice

There is minimal research investigating the influence of advice on decision-making in older age. The present study investigated the effect of different types of bad advice, relative to no advice, on young and older adults' decision-making in the Iowa Gambling Task (IGT). Fifty-four older adults and 59 young adults completed the IGT after receiving no advice, or advice to select from disadvantageous deck A (small, high-frequency losses), or disadvantageous deck B (larger, low-frequency losses). Corrugator EMG, memory and fluid intelligence were assessed. Averaged across advice conditions, older adults made more disadvantageous selections than young adults. There were no age-related differences in responding to bad advice, nor in corrugator activity in response to losses (i.e. frowning), or in learning to avoid deck A faster than deck B. Selecting from deck B was associated with reduced education among older adults, and reduced fluid intelligence among young adults. The data suggest that older adults make more disadvantageous decisions than young adults, and this is not exacerbated by bad advice. Both young and older adults are slower at learning to avoid choices resulting in low frequency relative to high-frequency losses, and this may be associated with individual differences in cognitive processing.

Do DEEPER ROOTING 1 Homologs Regulate the Lateral Root Slope Angle in Cucumber (Cucumis sativus)?

The architecture of the root system is fundamental to plant productivity. The rate of root growth, the density of lateral roots, and the spatial structure of lateral and adventitious roots determine the developmental plasticity of the root system in response to changes in environmental conditions. One of the genes involved in the regulation of the slope angle of lateral roots is DEEPER ROOTING 1 (DRO1). Its orthologs and paralogs have been identified in rice, Arabidopsis, and several other species. However, nothing is known about the formation of the slope angle of lateral roots in species with the initiation of lateral root primordia within the parental root meristem. To address this knowledge gap, we identified orthologs and paralogs of the DRO1 gene in cucumber (Cucumis sativus) using a phylogenetic analysis of IGT protein family members. Differences in the transcriptional response of CsDRO1, CsDRO1-LIKE1 (CsDRO1L1), and CsDRO1-LIKE2 (CsDRO1L2) to exogenous auxin were analyzed. The results showed that only CsDRO1L1 is auxin-responsive. An analysis of promoter-reporter fusions demonstrated that the CsDRO1, CsDRO1L1, and CsDRO1L2 genes were expressed in the meristem in cell files of the central cylinder, endodermis, and cortex; the three genes displayed different expression patterns in cucumber roots with only partial overlap. A knockout of individual CsDRO1, CsDRO1L1, and CsDRO1L2 genes was performed via CRISPR/Cas9 gene editing. Our study suggests that the knockout of individual genes does not affect the slope angle formation during lateral root primordia development in the cucumber parental root.

Decision-making style explains the withdrawal behavior of shy individuals: evidence from Chinese college students

Few studies have examined the mechanisms linking motivated behavior and reward-punishment stimuli in shy individuals. This study was designed to probe these mechanisms by examining shy and non-shy college student responses to both monetary rewards and penalties in the Iowa Gambling Task (IGT). Specifically, out of the 280 undergraduates surveyed in East China, 45 participants (18 boys) identified as shy and 45 (19 boys) identified as non-shy based on their shyness questionnaire scores were selected to participate in the IGT. Results revealed that shy participants selected favorable low-risk seeking decks (deck C) more frequently and adverse high-risk seeking decks (deck B) less frequently and were more inclined to change deck selection after incurring a net loss. Furthermore, the net score of shy students was higher than that of nonshy students. Results demonstrated that shy people were the winners of IGT games, indicating that they are more likely to exhibit risk-averse behaviors when making decisions. The results are discussed from the perspective of the decision-making style and practical implications of shy individuals.

Decision-making and frontoparietal resting-state functional connectivity among impulsive-compulsive diagnoses. Insights from a Bayesian approach

The Iowa Gambling Task (IGT) is one of the most widely used paradigms for assessing decision-making. An impairment in this process may be linked to several psychopathological disorders, such as obsessive-compulsive disorder (OCD), substance abuse disorder (SUD) or attention-deficit/hyperactivity disorder (ADHD), which could make it a good candidate for being consider a transdiagnostic domain. Resting-state functional connectivity (rsFC) has been proposed as a promising biomarker of decision-making. In this study, we aimed to identify idiosyncratic decision-making profiles among healthy people and impulsive-compulsive spectrum patients during the IGT, and to investigate the role of frontoparietal network (FPN) rsFC as a possible biomarker of different decision-making patterns. Using functional near-infrared spectroscopy (fNIRS), rsFC of 114 adults (34 controls; 25 OCD; 41 SUD; 14 ADHD) was obtained. Then, they completed the IGT. Hybrid clustering methods based on individual deck choices yielded three decision-makers subgroups. Cluster 1 (n = 27) showed a long-term advantageous strategy. Cluster 2 (n = 25) presented a maladaptive decision-making strategy. Cluster 3 (n = 62) did not develop a preference for any deck during the task. Interestingly, the proportion of participants in each cluster was not different between diagnostic groups. A Bayesian general linear model showed no credible differences in the IGT performance between diagnostic groups nor credible evidence to support the role of FPN rsFC as a biomarker of decision-making under the IGT context. This study highlights the importance of exploring in depth the behavioral and neurophysiological variables that may drive decision-making in clinical and healthy populations.

De Novo Assembly and Comparative Analysis of the Complete Mitochondrial Genome of Chaenomeles speciosa (Sweet) Nakai Revealed the Existence of Two Structural Isomers

As a valuable Chinese traditional medicinal species, Chaenomeles speciosa (Sweet) Nakai (C. speciosa) is a natural resource with significant economic and ornamental value. However, its genetic information is not well understood. In this study, the complete mitochondrial genome of C. speciosa was assembled and characterized to explore the repeat sequences, recombination events, rearrangements, and IGT, to predict RNA editing sites, and to clarify the phylogenetic and evolutionary relationship. The C. speciosa mitochondrial genome was found to have two circular chromosomes as its major conformation, with a total length of 436,464 bp and 45.2% GC content. The mitochondrial genome contained 54 genes, including 33 unique protein-coding genes, 18 tRNAs, and 3 rRNA genes. Seven pairs of repeat sequences involving recombination events were analyzed. Both the repeat pairs, R1 and R2, played significant roles in mediating the major and minor conformations. In total, 18 MTPTs were identified, 6 of which were complete tRNA genes. There were 454 RNA editing sites in the 33 protein-coding sequences predicted by the PREPACT3 program. A phylogenetic analysis based on 22 species of mitochondrial genomes was constructed and indicated highly conserved PCG sequences. Synteny analyses showed extensive genomic rearrangements in the mitochondrial genome of C. speciosa and closely related species. This work is the first to report the C. speciosa mitochondrial genome, which is of great significance for conducting additional genetic studies on this organism.

Integrated versus trial specific focus improves decision-making in older preschoolers

This study explored the effect of integrated-focus (focusing on a depiction of overall gains/losses) versus trial-focus (focusing on gains/losses at each trial) on choice in a preschool variant of the Iowa Gambling task. Participants included 65 preschoolers (M = 47.82, SD = 7.29). Children completed two versions of the Preschool Gambling task, three cool executive function tasks, a moral reasoning task, and an affective perspective taking task. The results indicated that while the integrated-focus condition led to improvement in the awareness of the game, the condition effect was moderated by age for decision-making choice; older preschoolers showed improvement in decision-making in the integrated focus condition, while younger preschoolers showed no condition effect. Further analysis indicated that differences in the increase of advantageous choice across blocks and the condition effect were partly explained by these differences in awareness. Furthermore, a component of cool executive function (shifting) was associated with the latter phase of decision-making. The findings additionally indicated an association of advantageous decision-making with moral/emotional measures, suggesting that the PGT may be a potentially useful clinical tool for early assessment. Finally, the findings of the current study have implications for how hot and cool executive function abilities may work together to enable adaptive decisions.

Identification and characterization of immunoglobulin tau (IgT) in Asian Seabass (Lates calcarifer) and mucosal immune response to nervous necrosis virus

Mucosal immunity plays a critical role in the protection of teleost fish against infection, but mucosal immunoglobulin of important aquaculture species unique to Southeast Asia remained greatly understudied. In this study, the sequence of immunoglobulin T (IgT) from Asian sea bass (ASB) is described for the first time. IgT of ASB possesses the characteristic structure of immunoglobulin with a variable heavy chain and four CH4 domains. The CH2-CH4 domains and full-length IgT were expressed and CH2-CH4 specific antibody was validated against full-length IgT expressed in Sf9 III cells. Subsequent use of the anti-CH2-CH4 antibody in immunofluorescence staining confirmed the presence of IgT-positive cells in the ASB gill and intestine. The constitutive expression of ASB IgT was characterized in different tissues and in response to red-spotted grouper nervous necrosis virus (RGNNV) infection. The highest basal expression of secretory IgT (sIgT) was observed in the mucosal and lymphoid tissues such as the gills, intestine and head kidney. Following NNV infection, IgT expression was upregulated in the head kidney and mucosal tissues. Moreover, a significant increase in localized IgT was found in gills and intestines of infected fish on day 14 post-infection. Interestingly, a significant increase in NNV-specific IgT secretion was only observed in the gills of the infected group. Our results suggest that ASB IgT may play an important role in the adaptive mucosal immune responses against viral infection and could potentially be adapted as a tool for the evaluation of prospective mucosal vaccines and adjuvants for the species.

The role of selected nutraceuticals in management of prediabetes and diabetes: An updated review of the literature

Dysglycemia is a disease state preceding the onset of diabetes and includes impaired fasting glycemia and impaired glucose tolerance. This review aimed to collect and analyze the literature reporting the results of clinical trials evaluating the effects of selected nutraceuticals on glycemia in humans. The results of the analyzed trials, generally, showed the positive effects of the nutraceuticals studied alone or in association with other supplements on fasting plasma glucose and post-prandial plasma glucose as primary outcomes, and their efficacy in improving insulin resistance as a secondary outcome. Some evidences, obtained from clinical trials, suggest a role for some nutraceuticals, and in particular Berberis, Banaba, Curcumin, and Guar gum, in the management of prediabetes and diabetes. However, contradictory results were found on the hypoglycemic effects of Morus, Ilex paraguariensis, Omega-3, Allium cepa, and Trigonella faenum graecum, whereby rigorous long-term clinical trials are needed to confirm these data. More studies are also needed for Eugenia jambolana, as well as for Ascophyllum nodosum and Fucus vesiculosus which glucose-lowering effects were observed when administered in combination, but not alone. Further trials are also needed for quercetin.

Aberrations in carbohydrate metabolism in patients with diagnosed acromegaly - observational study

INTRODUCTION

Acromegaly is characterized by excessive secretion of growth hormone (GH). The incidence rate of acromegaly is 40 to 70 persons per one million people. Carbohydrate disorders often accompany the above pathology. The aim of this study was to examine the influence of high levels of somatotropin on aberrations in glycaemia in patients with acromegaly, and then a 5-year observation.

MATERIAL AND METHODS

The study group consisted of 86 patients (48 females and 38 males) with acromegaly diagnosed on the basis of clinical features, elevated insulin-like growth factor 1 (IGF-1) levels, and/or no inhibition of GH ≤ 1 ug/L secretion during 2 hours after an oral glucose load.

RESULTS

In the study group type 2 diabetes mellitus (T2DM) was diagnosed in 21 patients (24.4%). There were also 14 cases (16.3%) of the diagnosis of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) combined. The mean age of participants with concomitant T2DM was 52.1 years, while the mean age of those without carbohydrate metabolism disturbances was 46.1 years. During a 5-year observation, we noticed an increase level of glycated haemoglobin (HbA1c) and new cases of pre-diabetes and T2DM.

CONCLUSION

In patients with acromegaly the incidence rate of T2DM is 3-4 times higher than in the rest of the population, and it increases with age, especially after the patient reaches 55 years old.

Abnormal glucose regulation in Chinese patients with coronary artery disease: a gender analysis

BACKGROUND

Diabetes and impaired glucose regulation are very common in patients with coronary artery disease (CAD). In this study, we aim to investigate the prevalence of abnormal glucose regulation in men and women in Chinese CAD patients.

METHODS

In this retrospective study, 4100 patients (male, n = 2873; female, n = 1227)with CAD were enrolled. The mean age of these patients was 63 years. The demographic data, medical history, echocardiography findings and blood investigations were collected and analyzed.

RESULTS

In this population, 953 (24%) patients had definite diagnosis of type 2 diabetes mellitus, including 636 males (23%) and 317 females (27%). There was a higher prevalence of diabetes in females than men (p < 0.05). For the remaining patients, 48% (n = 959) undergone an oral glucose tolerance test (OGTT), which revealed that 83 male patients (12%) and 41 female patients (16%) suffered from the type 2 diabetes (p > 0.05). 283 men (40%) and 105 women (41%) had impaired glucose regulation (IGR) (p > 0.05). Only 338 men (25%) and 109 women (19%) showed the normal glucose regulation, implying a higher prevalence of abnormal glucose regulation in females (p < 0.01). The odd ratio (OR) showed that women were more prone to have diabetes mellitus or IGT than men and the OR was 1.44 and 1.43 respectively.

CONCLUSION

Abnormal glucose regulation is highly prevalent in CAD patients. The women are more prone to have diabetes mellitus or IGT than men.

Prevalence and Predictors of Impaired Glucose Tolerance and Diabetes Mellitus Type 2 in Patients with Polycystic Ovary Syndrome

Aim: To estimate the prevalence of impaired glucose tolerance (IGT) and diabetes mellitus type 2 (DMT2), as well as the predictors for glucose abnormalities in women with polycystic ovary syndrome (PCOS). Material and methods: A cross-sectional study with 80 consecutive patients with newly diagnosed PCOS who underwent the standard 75g oral glucose tolerance test (OGTT) and the measurement of sex steroid hormone and lipid profile. Results: According to the results from the OGTT, 63% had a normal test (NT), 23% had IGT, and 9% had DMT2. The NT group was younger with lower BMI than IGT and DMT2 groups (25.1 ± 7.3, 31.5 ± 6.5, 37.4 ± 4.0 years, and 29.1 ± 8.3 kg/m2, 31.7 ± 4.6 kg/m2, and 34.5 ± 5.6 kg/m2, respectively). The testosterone levels were highest in the group with a normal test (2.7 ± 0.8 nmol/l) and lowest in the DMT2 group (1.9 ± 0.8 nmol/L), with statistical significance. The sex hormone bounding globulin (SHBG) levels were low in all three groups, with statistically significant differences between NG and IGT, and the NT and DMT2 groups. The multivariate linear regression model identified age, BMI, SHBG and testosterone as major independent predictors for abnormal glucose metabolism. Conclusion: It seems that the prevalence of IGT and DMT2 among PCOS women in our country is not as high as in Western countries. Age, BMI, and SHBG increase the risk for the development of IGT and DMT2. Thus, close monitoring of older, obese women with low SHBG is needed because of the higher risk for the development of IGT and DMT2 in such patients.

The Performance of College Students on the Iowa Gambling Task: Differences Between Scoring Approaches

The Iowa Gambling Task (IGT) is one of the most common behavioral decision-making tasks used in clinical and research settings. Less-than-expected performance among healthy adults generates concerns about the validity of this task, and it is possible the particular scoring approach utilized could impact interpretation. We examined how performance patterns changed across several scoring approaches, utilizing a large, college student sample, both with (n = 406) and without (n = 1,547) a self-reported history of psychiatric or other diagnosis. Higher net scores were seen when participants selected decks with a low loss frequency than decks with high long-term outcomes; however, participants overall underperformed the IGT normative data sample. Receiver operating characteristic curves examining multiple scoring approaches revealed no threshold of impaired performance that both maximized sensitivity and minimized false positive rate on the IGT. Scoring approach matters in the determination of impaired decision making via the IGT in adults.

Normatively Irrelevant Affective Cues Affect Risk-Taking under Uncertainty: Insights from the Iowa Gambling Task (IGT), Skin Conductance Response, and Heart Rate Variability

Being able to distinguish between safe and risky options is paramount in making functional choices. However, deliberate manipulation of decision-makers emotions can lead to risky behaviors. This study aims at understanding how affective reactions driven by normatively irrelevant affective cues can interfere with risk-taking. Good and Bad decks of the Iowa Gambling Task have been manipulated to make them unpleasant through a negative auditory manipulation. Anticipatory skin conductance response (SCR) and heart rate variability (HRV) have been investigated in line with the somatic marker hypothesis. Results showed fewer selections from Good decks when they were negatively manipulated (i.e., Incongruent condition). No effect of the manipulation was detected when Bad decks were negatively manipulated (i.e., Congruent condition). Higher anticipatory SCR was associated with Bad decks in Congruent condition. Slower heart rate was found before selections from Good decks in Control and Congruent condition and from Bad decks in Incongruent condition. Differences in heart rate between Bad and Good decks were also detected in Congruent condition. Results shed light on how normatively irrelevant affective cues can interfere with risk-taking.

Heart Rate Variability and Decision-Making: Autonomic Responses in Making Decisions

Decision-making is one of the most crucial cognitive processes in daily life. An adaptable, rapid, and flexible decision requires integration between brain and body. Heart rate variability (HRV) indexes this brain–body connection and appears to be related to cognitive performance. However, its relationship with decision-making is poorly analyzed. This study investigates the relationship between HRV and the decision-making process, assessed through the Iowa Gambling Task (IGT). One hundred and thirty healthy university students (mean age = 23.35 ± 2.50) participated in the study. According to IGT performance, they were divided into high decision-makers (n = 79) and low decision-makers (n = 51). Heart rate variability was measured in the resting, reactivity (i.e., during IGT), and recovery phases. Higher vagally mediated HRV (vmHRV; indexed in frequency domain measures) was evidenced in good decision-makers in the resting, reactivity, and recovery phases. During the task, a higher vagal modulation after a first evaluation was highlighted in good decision-makers. In conclusion, HRV proves to be a valid index of inhibitory circuit functioning in the prefrontal cortex. The relationship with cognitive functions was also confirmed, considering the ability to inhibit disadvantageous responses and make better decisions.

Toward targeted prevention: risk factors for prediabetes defined by impaired fasting glucose, impaired glucose tolerance and increased HbA1c in the population-based KORA study from Germany

AIMS

To identify socioeconomic, behavioral and clinical factors that are associated with prediabetes according to different prediabetes definition criteria.

METHODS

Analyses use pooled data of the population-based Cooperative Health Research in the Region of Augsburg (KORA) studies (n = 5312 observations aged ≥ 38 years without diabetes). Prediabetes was defined through either impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or elevated HbA1c according to thresholds of the American Diabetes Association. Explanatory variables were regressed on prediabetes using generalized estimating equations.

RESULTS

Mean age was 58.4 years; 50% had prediabetes (33% had IFG, 16% IGT, and 26% elevated HbA1c, 10% fulfilled all three criteria). Age, obesity, hypertension, low education, unemployment, statutory health insurance, urban residence and physical inactivity were associated with prediabetes. Male sex was a stronger risk factor for IFG (OR = 2.5; 95%-CI: 2.2-2.9) than for IGT or elevated HbA1c, and being unemployed was a stronger risk factor for IGT (OR = 3.2 95%-CI: 2.6-4.0) than for IFG or elevated HbA1c.

CONCLUSIONS

The overlap of people with IFG, IGT and elevated HbA1c is small, and some factors are associated with only one criterion. Knowledge on sociodemographic and socioeconomic risk factors can be used to effectively target interventions to people at high risk for type 2 diabetes.

Behavioral and Neural Arguments of Motivational Influence on Decision Making During Uncertainty

The scientific world is increasingly interested in motivation, primarily due to the suspected impact on decision-making abilities, particularly in uncertain conditions. To explore this plausible relationship, 28 healthy participants were included in the study and performed decision-making and motivational tasks while their neural activity was recorded. All participants performed the Iowa Gambling Task (IGT) and were split into two groups based on their score, one favorable group with 14 participants who performed advantageously and one undecided group with 14 participants who failed to develop the correct strategy on the IGT. In addition, all participants performed the Effort Expenditure for Reward Task (EEfRT), which defines the motivational level of each participant by the effort that participants agree to do in function of reward magnitudes and probabilities to receive these reward (10, 50, and 90%). The completion of both tasks allowed for the exploration of the relationship between the motivational level and decision-making abilities. The EEfRT was adapted to electroencephalography (EEG) recordings to explore how motivation could influence reward experience. Behavioral results showed no difference in EEfRT performances on the whole task between the two groups’ performances on the IGT. However, there was a negative correlation between the difficulty to develop an optimal strategy on the IGT and the percentage of difficult choices at the 90% condition on the EEfRT. Each probability condition has been previously associated to different motivational and emotional states, with the 90% condition associated to the reward sensitivity. This behavioral result leads to the hypothesis that reward sensitivity may induce an inability to develop an optimal strategy on the IGT. Group analysis demonstrated that only the undecided group showed a P300 during the processing of the outcome, whereas the favorable group showed a blunted P300. Similarly, there was a negative correlation between the P300 amplitude and the ability to develop an optimal strategy on the IGT. In conclusion, behavioral and neuronal data provides evidence that the propensity to focus only on the immediate outcomes is related to the development of an inefficient strategy on the IGT, without influence of motivation.

Association between triclocarban and triclosan exposures and the risks of type 2 diabetes mellitus and impaired glucose tolerance in the National Health and Nutrition Examination Survey (NHANES 2013-2014)

BACKGROUND

There has been increasing interest in the concept that exposure to environmental chemicals may be contributing factors to epidemics of diabetes mellitus (DM). Triclocarban and triclosan (TCs) are synthetic antibacterial chemicals that are widely used in personal care products. Studies have shown that TCs are endocrine disruptors that alter metabolic conditions. However, it remains unclear whether exposure to TCs is a risk factor for impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM).

OBJECTIVE

We explored the hypothesis that TCs exposure is associated with an increased risk of IGT and T2DM.

METHOD

To test our hypothesis, we analyzed the U.S. National Health and Nutrition Examination Survey (NHANES) cross-sectional data from 2013 to 2014. IGT and T2DM were diagnosed based on an oral glucose tolerance test (OGTT) and the WHO standards. The levels of urinary TCs were measured using an HPLC-MS/MS method that NHANES investigators developed. The association between urinary TCs status and IGT and T2DM was examined separately in men and women using multivariable logistic regression models adjusted for age, race, BMI, education, ratio of family income to poverty, smoking, exercise and hypertension.

RESULTS

Nine hundred US participants (429 men and 471 women) were included in the analysis, of whom 242 (26.89%) were diagnosed with T2DM and 117 (13.00%) had IGT. Among women, there was a significant positive association between triclocarban, but not triclosan exposure and T2DM (OR: 1.79, 95% CI: 1.05, 2.05) after adjusting for potential confounding factors. Among men, no significant association between TCs exposure and IGT or T2DM was observed.

CONCLUSIONS

Triclocarban exposure may increase the risk of T2DM in the women, although additional studies are needed to confirm the results of this study and to investigate the underlying mechanisms.

The role of inhibition capacities in the Iowa gambling test performance in young tattooed women

Background

Using the Iowa Gambling Test (IGT), we demonstrated previously impaired decision- making process in young tattooed women. The purpose of the present study was to explore the associations among the three facets of impaired inhibition (response inhibition, reflection inhibition and interference inhibition) and decision-making processes in this population.

Methods

To this end, the participants of the previous study (60 tattooed women and 60 non-tattooed women) were assessed in the Go/NoGo task, a measure of response inhibition, the Matched Familiar Figure Test (MFFT), a measure of reflection inhibition and the Stroop task a measure of interference inhibition.

Results

Tattooed women were significantly slower than non-tattooed women in the Go/NoGo performance; however, no differences were detected in the MFFT and the Stroop task. A hierarchical regression analysis did not reveal any significant main effects of these inhibition measures on the IGT performance.

Conclusions

These findings do not support the hypothesis that risky decision in young tattooed women is due to impaired inhibitory control. Further studies are needed to identify the cognitive mechanisms involved in the tendency to risky decisions in young tattooed women.

Behavioral and Electrophysiological Arguments in Favor of a Relationship between Impulsivity, Risk-Taking, and Success on the Iowa Gambling Task

The aim of the present study was to investigate the relationship between trait impulsivity, risk-taking, and decision-making performance. We recruited 20 healthy participants who performed the Iowa Gambling Task (IGT) and the Balloon Analog Risk Task (BART) to measure decision-making and risk-taking. The impulsivity was measured by the Barratt Impulsiveness Scale. Resting-state neural activity was recorded to explore whether brain oscillatory rhythms provide important information about the dispositional trait of impulsivity. We found a significant correlation between the ability to develop a successful strategy and the propensity to take more risks in the first trials of the BART. Risk-taking was negatively correlated with cognitive impulsivity in participants who were unable to develop a successful strategy. Neither risk-taking nor decision-making was correlated with cortical asymmetry. In a more exploratory approach, the group was sub-divided in function of participants’ performances at the IGT. We found that the group who developed a successful strategy at the IGT was more prone to risk, whereas the group who failed showed a greater cognitive impulsivity. These results emphasize the need for individuals to explore their environment to develop a successful strategy in uncertain situations, which may not be possible without taking risks.

Circulating microRNA-21 is an early predictor of ROS-mediated damage in subjects with high risk of developing diabetes and in drug-naïve T2D

BACKGROUND

Impaired glucose tolerance (IGT) is a risk factor for the development of diabetes and related complications that ensue. Early identification of at-risk individuals might be beneficial to reduce or delay the progression of diabetes and its related complications. Recently, microRNAs emerged as potential biomarkers of diseases. The aim of the present study was to evaluate microRNA-21 as a potential biomarker for the risk of developing diabetes in adults with IGT and to investigate its downstream effects as the generation of reactive oxygen species (ROS), the induction of manganese-superoxide dismutase-2 (SOD2), and the circulating levels of 4-HNE (4-hydroxynonenal).

METHODS

To evaluate the prognostic and predictive values of plasmatic microRNA-21 in identifying metabolic derangements, we tested a selected cohort (n = 115) of subjects enrolled in the DIAPASON Study, whom were selected on ADA criteria for 2hPG. Statistical analysis was performed using ANOVA or the Kruskal-Wallis test as appropriate. ROC curves were drawn for diagnostic accuracy of the tests; positive and negative predictive values were performed, and Youden's index was used to seek the cut-off optimum truncation point. ROS, SOD2 and 4-HNE were also evaluated.

RESULTS

We observed significant upregulation of microRNA-21 in IGT and in T2D subjects, and microRNA-21 was positively correlated with glycaemic parameters. Diagnostic performance of microRNA-21 was high and accurate. We detected significant overproduction of ROS by electron paramagnetic resonance (EPR), significant accumulation of the lipid peroxidation marker 4-HNE, and defective SOD2 antioxidant response in IGT and newly diagnosed, drug-naïve T2D subjects. In addition, ROC curves demonstrated the diagnostic accuracy of markers used.

CONCLUSIONS

our data demonstrate that microRNA-21 is associated with prediabetic status and exhibits predictive value for early detection of glucose imbalances. These data could provide novel clues for miR-based biomarkers to evaluate diabetes.

Efficacy and safety of berberine for dyslipidaemias: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

In recent years, berberine has become widely used as an effective alternative to treat dyslipidaemias; much clinical evidence has emerged. It is important to systematically and critically evaluate the existing evidence.

PURPOSE

This study aims to evaluate the efficacy and safety of berberine in patients with dyslipidaemias.

STUDY DESIGN

A systematic review and meta-analysis of randomized clinical trials.

METHODS

Five electronic databases were searched up to Apr 15, 2018 to identify randomized controlled trials (RCTs) of berberine in treatment of dyslipidaemias. The outcomes were lipid profile parameters and adverse events. Study selection, data collection, risk of bias assessment, data analyses and interpretations were conducted according to the Cochrane handbook.

RESULTS

Sixteen trials with total of 2147 participants were judged to be eligible and were included in the meta-analysis. The included trials were assessed to be of high clinical heterogeneity. The methodological quality of the majority of the trials was generally low in terms of random sequence generation, allocation concealment, blinding and incomplete outcome data. Thus, selection bias, performance bias, detection bias, attrition bias and confounding bias might exist. Meta-analysis showed that berberine significantly reduced levels of total cholesterol (TC) (MD = -0.47  mmol/l 95% CI [-0.64, -0.31], p < 0.00001), low-density lipoprotein cholesterol (LDL-C) (MD =-0.38  mmol/l 95% CI [-0.53, -0.22], p < 0.00001) and triglycerides (TG) (MD = -0.28  mmol/l 95% CI [-0.46, -0.10], p = 0.002). Berberine also increased the level of high-density lipoprotein cholesterol (HDL-C) when used alone (MD = 0.08  mmol/l 95% CI [0.03, 0.12], p = 0.001). No significant differences were found between groups in terms of incidence of adverse events (RR = 0.64 95% CI [0.31, 1.30], p = 0.22). No severe adverse effects were reported in either group.

CONCLUSION

Berberine improves lipid profiles in dyslipidaemias with satisfactory safety. Nevertheless, these findings should be interpreted with caution because of the high clinical heterogeneity and high risk of bias in the included trials. Rigorous clinical trials should be carried out to provide more reliable evidence.

Five-year effectiveness of short messaging service (SMS) for pre-diabetes

Objective

An observational post-randomized controlled trial (RCT) design was adopted to evaluate the long-term sustainability and maintenance of improved glycemic control, lipid profile, reduced progression to diabetes at 3-year following a 2-year short messaging service (SMS). We performed a naturalistic follow-up to the 104 participants of SMS intervention, a 2-year randomized controlled trial comparing the SMS to non-SMS for pre-diabetes. All participants were arranged screening for diabetes at 5-year assessment. Primary outcome of this post-RCT study was cumulative incidence of diabetes whereas secondary outcomes were the change in biometric data over a 5-year period.

Results

After a mean 57-month follow-up, 19 (18.3%) were lost to follow-up after the RCT period. Progression to diabetes occurred in 20 and 16 patients among the intervention and control group respectively, with no significant between-group difference (8.06 and 7.31 cases per 100 person years, respectively; Hazard Ratio in the intervention group, 1.184; 95% confidence interval, 0.612 to 2.288; p-value = 0.616). No significant effect of SMS on reduction in diabetes was observed in overall and pre-defined subgroups. The SMS intervention preserved the clinical benefits within the trial period but failed to transform from treatment efficacy to long-term effectiveness beyond 2 years after intervention.

Trail registration ClinicalTrials.gov Identifier NCT01556880, retrospectively registered on March 16, 2012

Personality Traits and Cortical Activity Affect Gambling Behavior in Parkinson's Disease

BACKGROUND

Pathological gambling (PG) in Parkinson's disease (PD) manifests as a persistent and uncontrollable gambling behavior, characterized by dysfunctional decision-making and emotional impairment related to high-risk decisions.

OBJECTIVE

The aim of this study was to explore the relationship between personality traits and prefrontal cortex activity in PD patients with or without PG.

METHODS

Thus, hemodynamic cortical activity measured by functional near-infrared spectroscopy (fNIRS) and Iowa Gambling Task (IGT) performance were recorded in forty-six PD patients, divided into three groups according to their gambling status: PD patients with active gambling behavior (PDG); PD patients who remitted from PG (PDNG); and a control group (CG) composed by patients with PD only.

RESULTS

Results indicates that gambling behavior in PD patients is strongly predictive of dysfunctional cognitive strategy; affecting anomalous cortical response with a left hemispheric unbalance in dorsal areas; and it is related to more reward sensitivity than impulsivity personality components.

CONCLUSIONS

PDG patients differed from PDNG and CG from both behavioral and brain response to decision-making. Overall, these effects confirm a pathological condition related to cognitive and emotional aspects which makes the patients with PGD victims of their dysfunctional behavior.

Effects of medicinal food plants on impaired glucose tolerance: A systematic review of randomized controlled trials

BACKGROUND

The objective of this systematic review was to assess available scientific data on the efficacy and safety of medicinal food plants for the treatment of impaired glucose tolerance.

METHODS

We included randomized controlled trials (RCTs) with a minimum follow-up period of 6weeks. The diagnosis was determined by fasting plasma glucose values after two-hour oral glucose tolerance testing (OGTT). Two authors independently extracted data and evaluated bias. The Cochrane tool of risk of Bias Tool was used.

RESULTS

This review included ten trials. Most studies were highly biased as data were incomplete or reporting was selective. The two-hour fasting plasma glucose after the curcumin extract intervention showed statistical significance after 3, 6 and 9months: p<0.01. Also, glycosylated haemoglobin levels A1c (HbA1c) values after curcumin extract intervention showed statistical significance after 3, 6 and 9months: p<0.01. Insulin resistance (HOMA-IR) after curcumin extract intervention showed statistical significance after 6months and after 9months: p<0.05 and p<0.01.

CONCLUSIONS

Curcumin has shown the confident results to be effective for the treatment of impaired glucose tolerance. Fenugreek and flaxseed may also be effective, but due to low quality of these studies the results must be interpreted with caution.

Binge Drinking Trajectory and Decision-Making during Late Adolescence: Gender and Developmental Differences

Objective: Impaired affective decision-making has been consistently related to alcohol dependence. However, less is known about decision-making and binge drinking (BD) in adolescents. The main goal of this longitudinal study was to determine the association between BD and decision-making from late adolescence to early adulthood. A second aim is to assess developmental changes and performance differences in males and females.

Method: An initial sample of 155 1st-year university students, (76 non-BDs, 40 females; and 79 BDs, 39 females), was followed prospectively over a 4-year period. The students were classified as stable non-BDs, stable BDs and ex-BDs according to their scores in item 3 of the AUDIT and the speed of alcohol consumption. Decision-making was assessed by the Iowa Gambling Task (IGT) three times during the study. Dependent variables were net gain and net loss. Results were analyzed using generalized linear mixed models.

Results: A stable BD pattern was not associated with either disadvantageous decision-making or sensitivity to loss frequency. Performance improved significantly in both genders over the study period, especially in the last blocks of the task. Females showed a higher sensitivity to loss frequency than males. No gender-related differences were observed in gains.

Conclusion: Performance in affective decision-making continues to improve in late adolescence, suggesting neuromaturational development in both genders. Females are more sensitive to loss frequency. Stable BD during late adolescence and emerging adulthood is not associated with deficits in decision-making. Poor performance of the IGT may be related to more severe forms of excessive alcohol consumption.

Comparing glucose and hemoglobin A1c diagnostic tests among a high metabolic risk Hispanic population

BACKGROUND

Compare glycated hemoglobin (HbA1c ) diagnostic tests for prediabetes and diabetes with plasma glucose criteria and compare the metabolic profiles of people classified by HbA1c versus by glucose levels.

METHODS

Participants were recruited for the San Juan Overweight Adults Longitudinal Study. The participants were primarily Hispanic (98%), without previously diagnosed diabetes, and aged 40 to 65 years. Participants classified as normal glycemic, prediabetes, or diabetes on the basis of baseline HbA1c and plasma glucose criteria were compared with respect to baseline cardiometabolic factors.

RESULTS

The 1342 participants had a mean age of 50.5 ± 6.8 years and 28% were men. Thirty-one percent were diagnosed with prediabetes by plasma glucose criteria and 53.4% by HbA1c , and 8.1% were diagnosed with diabetes by plasma glucose criteria and 6.3% by HbA1c ; overall concordance rate was 55.1%. The area under the receiver operating characteristic curve of HbA1c compared to plasma glucose criteria was 0.62 for impaired glucose and 0.76 for diabetes. A worse cardiometabolic profile was seen within subgroups that met HbA1c and plasma glucose criteria for diabetes or prediabetes. Those diagnosed with prediabetes by plasma glucose criteria had significantly higher systolic blood pressure and higher homeostatic model assessment than those diagnosed using HbA1c . Participants diagnosed with diabetes by plasma glucose criteria had lower body mass index, smaller waist circumference, and lower insulinogenic and disposition indices, but higher homeostatic model assessment of insulin resistance, than those diagnosed by HbA1c .

CONCLUSIONS

Low concordance was seen between HbA1c and glucose measurements. The HbA1c is not a good test for prediabetes but shows reasonable validity for diabetes in this high-risk predominantly female Hispanic population. People classified by HbA1c , plasma glucose criteria, or both show different metabolic profiles; a combined test may be ideal.

Aging and risky decision-making: New ERP evidence from the Iowa Gambling Task

Several pieces of evidence have highlighted the presence of an age-related decline in risky decision-making (DM), but the reason of this decline is still unclear. The aim of the present study was to investigate the neural correlates of feedback processing in risky DM. Twenty-one younger (age <50 years) and 15 older (age >50 years) adults were tested with the Iowa Gambling Task (IGT) during Event Related Potentials (ERP) recording. The analysis was focused on the feedback-related negativity (FRN) and P3, two ERP components that represent different stages of feedback processing. Behavioral results revealed that older adults, despite showing a significant learning trend, completed the IGT with a gain of a smaller amount of money compared to the younger ones. ERP results revealed that while the FRN response was comparable in the two groups, the P3 amplitude was significantly reduced after negative feedback in older adults, compared with the younger ones. Furthermore, the difference in the P3 amplitude evoked by positive and negative feedback was significantly correlated with age. Hence, the present findings suggest that older adults seem to be less willing to shift attention from positive to negative information, and that this relevant change in the later stages of feedback processing could be the cause of a poor performance in risky DM contexts.

Anodal Stimulation of the Left DLPFC Increases IGT Scores and Decreases Delay Discounting Rate in Healthy Males

Previous correlational imaging studies have implicated the dorsolateral prefrontal cortex (DLPFC) in decision making. Using High-Definition Transcranial Direct Current Stimulation (HD-tDCS), the present study directly investigated the causal role of the DLPFC in performing the Iowa Gambling Task (IGT) and the Inter-Temporal Choice (ITC) task. Three experiments were conducted: Experiment 1 (N = 41) to study the left DLPFC, Experiment 2 (N = 49) to study the right DLPFC, and Experiment 3 (N = 20, a subset of those in Experiment 1) to switch the experimental and control conditions. All participants were healthy male college students. For Experiments 1 and 2, participants were randomly assigned to either the HD-tDCS or the sham stimulation condition. For Experiment 3, participants were assigned to the condition they were not in during Experiment 1. Results showed that HD-tDCS over the left DLPFC increased IGT score, decreased the recency parameter in IGT, and lowered delay discounting rate (k) in the ITC task. We discussed the potential roles of impulse control and time perception in mediating the effect of tDCS stimulation of left DLPFC on decision making. Our results have clinical implications for the treatment of disorders involving poor decision-making, such as addictions.

IGT-Open: An open-source, computerized version of the Iowa Gambling Task

The Iowa Gambling Task (IGT) is commonly used to understand the processes involved in decision-making. Though the task was originally run without a computer, using a computerized version of the task has become typical. These computerized versions of the IGT are useful, because they can make the task more standardized across studies and allow for the task to be used in environments where a physical version of the task may be difficult or impossible to use (e.g., while collecting brain imaging data). Though these computerized versions of the IGT have been useful for experimentation, having multiple software implementations of the task could present reliability issues. We present an open-source software version of the Iowa Gambling Task (called IGT-Open) that allows for millisecond visual presentation accuracy and is freely available to be used and modified. This software has been used to collect data from human subjects and also has been used to run model-based simulations with computational process models developed to run in the ACT-R architecture.

Role of MicroRNA 126 in screening, diagnosis, and prognosis of diabetic patients in Egypt

MicroRNAs (miRNAs), family of non-coding small RNAs, play a vital role in the regulation of blood glucose level. We aimed to investigate the relation of serum miRNA-126 expression with impaired glucose tolerance as well as type 2 diabetes mellitus (T2DM) patients with and without complications. One hundred healthy controls, eighty-six patients with IGT, and one hundred patients with T2DM were recruited in this study. Serum miRNA-126 expression was assessed by quantitative real-time polymerase chain reaction. We found a significant decrease of serum miRNA-126 expression between IGT patients as well as diabetic patients when both compared with controls and between diabetic patients compared to IGT patients. A significant decrease of serum miRNA-126 expression was detected in diabetic patients with complications compared to those without evident complications especially those with diabetic macrovascular complications and diabetic retinopathy. Serum microRNA-126 expression could be a good marker for diagnosis of IGT and T2DM as well as for monitoring the outcomes of such disease. © 2016 IUBMB Life, 68(6):452-458, 2016.

Older Age, Higher Body Mass Index and Inflammation Increase the Risk for New-Onset Diabetes and Impaired Glucose Tolerance in Patients on Peritoneal Dialysis

♦

OBJECTIVES

To identify predictors of new-onset diabetes and impaired glucose tolerance (IGT) events in patients undergoing peritoneal dialysis (PD) based on baseline and time-dependent covariates, respectively. ♦

METHODS

In this prospective, single center-based cohort, all non-diabetic incident PD patients between August 2003 and August 2011 were included. All demographic and laboratory data were recorded at baseline. Repeated measurements for laboratory, dialysis prescription, and nutrition parameters were recorded at regular intervals. Multivariable Cox regression models built from baseline and time-dependent variables respectively were used to calculate the hazard ratio (HR) of potential predictors for new-onset diabetes and IGT (NODI). ♦

RESULTS

Of the 612 PD patients, 25 (4.1%) and 7 (1.1%) patients were identified with NODI, respectively, during a mean follow-up period of 32.4 (12.9 - 60.8) months. Using multivariable Cox regression analysis, age and body mass index (BMI) at baseline were significantly associated with NODI after adjustment for potential confounders. During follow-up, time-dependent BMI and serum high-sensitive C-reactive protein (HS-CRP) independently predicted the risk for NODI. Patients with NODI had significantly elevated plasma glucose concentrations and BMI from the start of PD therapy, with serum HS-CRP maintained at high levels. Dietary/dialysate energy intake and other laboratory parameters were not correlated with NODI risk either as baseline or time-dependent variables. ♦

CONCLUSIONS

Traditional and uremic-related risk factors, such as older age, higher BMI, and inflammation, contribute to new-onset diabetes and impaired glucose tolerance in PD patients.

Decision-making deficits in patients with chronic schizophrenia: Iowa Gambling Task and Prospect Valence Learning model

PURPOSE

Decision-making is the process of forming preferences for possible options, selecting and executing actions, and evaluating the outcome. This study used the Iowa Gambling Task (IGT) and the Prospect Valence Learning (PVL) model to investigate deficits in risk-reward related decision-making in patients with chronic schizophrenia, and to identify decision-making processes that contribute to poor IGT performance in these patients.

MATERIALS AND METHODS

Thirty-nine patients with schizophrenia and 31 healthy controls participated. Decision-making was measured by total net score, block net scores, and the total number of cards selected from each deck of the IGT. PVL parameters were estimated with the Markov chain Monte Carlo sampling scheme in OpenBugs and BRugs, its interface to R, and the estimated parameters were analyzed with the Mann-Whitney U-test.

RESULTS

The schizophrenia group received significantly lower total net scores compared to the control group. In terms of block net scores, an interaction effect of group × block was observed. The block net scores of the schizophrenia group did not differ across the five blocks, whereas those of the control group increased as the blocks progressed. The schizophrenia group obtained significantly lower block net scores in the fourth and fifth blocks of the IGT and selected cards from deck D (advantageous) less frequently than the control group. Additionally, the schizophrenia group had significantly lower values on the utility-shape, loss-aversion, recency, and consistency parameters of the PVL model.

CONCLUSION

These results indicate that patients with schizophrenia experience deficits in decision-making, possibly due to failure in learning the expected value of each deck, and incorporating outcome experiences of previous trials into expectancies about options in the present trial.

Osteocalcin and type 2 diabetes risk in Latinos: a life course approach

OBJECTIVE

To examine associations between circulating levels of the bone-derived protein osteocalcin (OC) and type 2 diabetes (T2D) risk in Latino children and adults.

METHODS

Serum OC was measured in 136 children and 531 adults who had the following T2D risk factors assessed, body mass index (BMI), Hemoglobin A1c (HbA1c), fasting and 2-hour glucose during an oral glucose tolerance test.

RESULTS

OC was significantly higher in children than adults (209.0 ± 12.1 vs. 41.0 ± 0.9 ng/ml, p<0.0001). In adults, OC was inversely associated (all p<0.001) with BMI (r=-0.2), HbA1c (r=-0.2), fasting glucose (r=-0.16), and 2-hour glucose (r=-0.21), while there were no significant associations in children. There was a stepwise decrease in OC with increasing dysglycemia in adults, normoglycemic (44.1 ± 1.3 ng/ml), prediabetic (39.3 ± 1.3 ng/ml), and T2D (31.8 ± 1.2 ng/ml), (p<0.0001), whereas there were no differences between normal and prediabetic youth (195.7 ± 16.1 vs. 194.7 ± 25.8 ng/ml, p=0.3).

CONCLUSIONS

OC was inversely associated with T2D risk in Latino adults; however, this pattern was not observed in children.

Oral magnesium supplementation improves glycaemic status in subjects with prediabetes and hypomagnesaemia: A double-blind placebo-controlled randomized trial

AIM

This study evaluated the efficacy of oral magnesium supplementation in the reduction of plasma glucose levels in adults with prediabetes and hypomagnesaemia.

METHODS

A total of 116 men and non-pregnant women, aged 30 to 65 years with hypomagnesaemia and newly diagnosed with prediabetes, were enrolled into a randomized double-blind placebo-controlled trial to receive either 30 mL of MgCl2 5% solution (equivalent to 382 mg of magnesium) or an inert placebo solution once daily for four months. The primary trial endpoint was the efficacy of magnesium supplementation in reducing plasma glucose levels.

RESULTS

At baseline, there were no significant statistical differences in terms of anthropometric and biochemical variables between individuals in the supplement and placebo groups. At the end of follow-up, fasting (86.9 ± 7.9 and 98.3 ± 4.6 mg/dL, respectively; P = 0.004) and post-load glucose (124.7 ± 33.4 and 136.7 ± 23.9 mg/dL, respectively; P = 0.03) levels, HOMA-IR indices (2.85 ± 1.0 and 4.1 ± 2.7, respectively; P = 0.04) and triglycerides (166.4 ± 90.6 and 227.0 ± 89.7, respectively; P = 0.009) were significantly decreased, whereas HDL cholesterol (45.6 ± 10.9 and 46.8 ± 9.2 mg/dL, respectively; P = 0.04) and serum magnesium (1.96 ± 0.27 and 1.60 ± 0.26 mg/dL, respectively; P = 0.005) levels were significantly increased in those taking MgCl2 compared with the controls. A total of 34 (29.4%) people improved their glucose status (50.8% and 7.0% in the magnesium and placebo groups, respectively; P < 0.0005).

CONCLUSION

Our results show that magnesium supplementation reduces plasma glucose levels, and improves the glycaemic status of adults with prediabetes and hypomagnesaemia.

Does Twice-weekly Cabergoline Improve Anthropometrical and Biochemical Profiles in Prediabetes? A Randomized Double-blind Clinical Trial Pilot Study

Dopaminergic signaling is one of the regulatory pathways being investigated for its implication in glucose metabolism. The aim of this study was to determine the effect of cabergoline on biochemical and anthropometric parameters in prediabetes stage (impaired fasting glucose and impaired glucose tolerance). In this double blind, placebo-controlled, pilot study, 27 prediabetic adults were randomized to receive 0.25-mg cabergoline twice weekly for two weeks, followed by 0.5 mg twice weekly for next 14 weeks (n = 13) or placebo (n = 14). All subjects were advised to follow a 500 kcal-deficit energy diet. Fasting plasma glucose (FPG), oral glucose tolerance, glycated hemoglobin (A1c), fasting, and 2-h insulin were measured at baseline and at 16-week follow-up. Homeostasis model assessment (HOMA) 2 was calculated to estimate steady-state beta-cell function, insulin sensitivity, and insulin resistance. Our results showed significant reductions in fasting (P = 0.004) and 2-h plasma glucose (P = 0.01) after treatment, and significant improvements in beta-cell function (P = 0.03) and insulin resistance (P = 0.04) in the cabergoline group. The trend of non-significant A1c changes was decreasing in the cabergoline group versus an increasing trend in the placebo group. All anthropometric parameters were similar between the two groups. Our results revealed that twice-weekly cabergoline could improve glucose metabolism in prediabetes stage. Larger studies of longer duration are warranted to investigate the effect of cabergoline in preventing progression of prediabetes to type 2 diabetes mellitus.

A novel test for IGT utilizing metabolite markers of glucose tolerance

The oral glucose tolerance test (OGTT) is the only method to diagnose patients having impaired glucose tolerance (IGT), but its use has diminished considerably in recent years. Metabolomic profiling studies have identified a number of metabolites whose fasting levels are associated with dysglycemia and type 2 diabetes. These metabolites may serve as the basis of an alternative test for IGT. Using the stable isotope dilution technique, quantitative assays were developed for 23 candidate biomarker metabolites. These metabolites were measured in fasting plasma samples taken just prior to an OGTT from 1623 nondiabetic subjects: 955 from the Relationship between Insulin Sensitivity and Cardiovascular Disease Study (RISC Study; 11.7% IGT) and 668 subjects from the Diabetes Mellitus and Vascular Health Initiative (DMVhi) cohort from the DEXLIFE project (11.8% IGT). The associations between metabolites, anthropometric, and metabolic parameters and 2hPG values were assessed by Pearson correlation coefficients and Random Forest classification analysis to rank variables for their ability to distinguish IGT from normal glucose tolerance (NGT). Multivariate logistic regression models for estimating risk of IGT were developed and evaluated using AUCs calculated from the corresponding ROC curves. A model based on the fasting plasma levels of glucose, α-hydroxybutyric acid, β-hydroxybutyric acid, 4-methyl-2-oxopentanoic acid, linoleoylglycerophosphocholine, oleic acid, serine and vitamin B5 was optimized in the RISC cohort (AUC = 0.82) and validated in the DMVhi cohort (AUC = 0.83). A novel, all-metabolite-based test is shown to be a discriminate marker of IGT. It requires only a single fasted blood draw and may serve as a more convenient surrogate for the OGTT or as a means of identifying subjects likely to be IGT.

Impact of gastric emptying to the glycemic and insulinemic responses to a 75-g oral glucose load in older subjects with normal and impaired glucose tolerance

The majority of studies relating to the oral glucose tolerance test (OGTT) have not taken gastric emptying (GE), which exhibits a substantial inter-individual variation, into account. We sought to evaluate the impact of GE, on the glycemic and insulinemic responses to a 75-g oral glucose load in older subjects with normal and impaired glucose tolerance. Eighty-seven healthy 'older' subjects (47F, 40M; age 71.0 ± 0.5 year) were given a drink comprising of 75-g glucose and 150 mg C(13)-acetate made up to 300 mL with water on a single occasion. Exhaled breath was obtained for analysis of (13)CO2 and calculation of the 50% GE time (T50). Blood glucose, serum insulin and plasma glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) were measured, and the insulin sensitivity index (ISI), and the disposition index (DI), were calculated. Thirty-one subjects had normal glucose tolerance (NGT) and 46 had impaired glucose tolerance (IGT). Blood glucose at t = 60 min and t = 120 min were related inversely to ISI (P < 0.001) and DI P < 0.001). The rise in blood glucose at t = 60 min was related inversely to the T50 in all subjects (P < 0.01), and those with IGT (P < 0.001), but not NGT. There were no significant relationships between the blood glucose at t = 120 min with the T50, but in both groups the change in blood glucose from baseline at t = 180 min was related (NGT: P < 0.001; IGT: P < 0.001) to the T50. We conclude that in NGT and IGT, the effect of GE on both the 'early' and 'late' glycemic responses to a 75-g oral glucose load is complementary to that of insulin sensitivity.

Pioglitazone decreases coronary artery inflammation in impaired glucose tolerance and diabetes mellitus: evaluation by FDG-PET/CT imaging

OBJECTIVES

The aim of this study was to compare the effect of pioglitazone with glimepiride on coronary arterial inflammation with serial (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) combined with computed tomography (CT) angiography.

BACKGROUND

Recent studies have shown that FDG-PET combined with CT is a reliable tool to visualize and quantify vascular inflammation. Although pioglitazone significantly prevented the progression of coronary atherosclerosis and reduced the recurrence of myocardial infarction in patients with type 2 diabetes mellitus (DM), it remains unclear whether pioglitazone could attenuate coronary artery inflammation.

METHODS

Fifty atherosclerotic patients with impaired glucose tolerance or type 2 DM underwent determination of blood chemistries, anthropometric and inflammatory variables, and FDG-PET/CT angiography, and then were randomized to receive either pioglitazone or glimepiride for 16 weeks. Effects of the treatments on vascular inflammation of the left main trunk were evaluated by FDG-PET/CT angiography at baseline and end of the study. Vascular inflammation of the left main trunk was measured by blood-normalized standardized uptake value, known as a target-to-background ratio.

RESULTS

Three patients dropped out of the study during the assessment or treatment. Finally, 25 pioglitazone-treated patients and 22 glimepiride-treated patients (37 men; mean age: 68.1 ± 8.3 years; glycosylated hemoglobin: 6.72 ± 0.70%) completed the study. After 16-week treatments, fasting plasma glucose and glycosylated hemoglobin values were comparably reduced in both groups. Changes in target-to-background ratio values from baseline were significantly greater in the pioglitazone group than in the glimepiride group (-0.12 ± 0.06 vs. 0.09 ± 0.07, p = 0.032), as well as changes in high-sensitivity C-reactive protein (pioglitazone vs. glimepiride group: median: -0.24 [interquartile range (IQR): -1.58 to -0.04] mg/l vs. 0.08 [IQR: -0.07 to 0.79] mg/l, p = 0.031).

CONCLUSIONS

Our study indicated that pioglitazone attenuated left main trunk inflammation in patients with impaired glucose tolerance or DM in a glucose-lowering independent manner, suggesting that pioglitazone may protect against cardiac events in patients with impaired glucose tolerance or DM by suppressing coronary inflammation. (Anti-Inflammatory Effects of Pioglitazone; NCT00722631).

A home-based method for the detection of impaired glucose tolerance in hypertensive primary care patients

OBJECTIVE

The aim of this project was to compare an oral glucose tolerance test (OGTT) partly performed in the patient's home (OGTTh) with a clinic-obtained OGTT with regard to the ability of the tests to identify patients with impaired glucose tolerance (IGT) and type 2 diabetes mellitus (DM-2).

DESIGN

A method comparison.

SETTING

The study was completed at two primary health care centres.

SUBJECTS

Fifty-one patients with hypertension aged 50-79 years completed both OGTT tests.

MAIN OUTCOME MEASURES

Values for capillary P-glucose obtained two hours after a glucose load were compared between the two OGTT tests. Fasting plasma glucose (fP-glucose) and HbA1c were also measured.

RESULTS

Thirty-seven patients were classified in the same group (normal/IGT/DM-2) by the two tests. The index of validity based on the test's ability to identify normal or pathological values (≥ 8.9 mmol/l) was 0.75. The value for kappa was 0.66 with a sensitivity of 0.54 and a specificity of 0.82.

CONCLUSION

OGTTh may be a useful screening method for IGT in risk groups such as hypertensive patients.

Use of drugs related to the treatment of diabetes mellitus and other cardiovascular risk factors in the Spanish population. The Di@bet.es study

INTRODUCTION AND OBJECTIVES

To assess the patterns of use of 8 therapeutic drug groups for the treatment of diabetes mellitus and other cardiovascular risk factors, and to identify sociodemographic and health determinants of their use in the overall Spanish population.

METHODS

A representative sample of the Spanish population within the Di@bet.es study, a cross-sectional population-based survey, was included.

STUDY VARIABLES

sociodemographic, clinical, and lifestyle data; physical examination, and an oral glucose tolerance test in patients without known diabetes mellitus. Furthermore, patients were systematically queried about current medication use, and 8 pharmacotherapeutic groups were evaluated: lipid-lowering therapy, antihypertensives, oral hypoglycemic agents, insulin, thyroid hormone, uricosurics, psychoactive drugs, and nonsteroidal anti-inflammatory drugs.

RESULTS

Sixty-six percent of the Spanish population was taking at least one medication. Therapeutic drug use was associated with age, independently of the higher prevalence of diabetes mellitus, hypertension, or hyperlipidemia in older patients. Sex disparities were found in the use of lipid-lowering agents, allopurinol, levothyroxine, nonsteroidal anti-inflammatory drugs, and psychoactive drugs. Use of psychoactive drugs was related to education level, work status, physical activity, smoking, and alcohol consumption. Almost 30% of patients with diabetes mellitus were taking 6 or more medications daily. Diabetes mellitus was associated with greater use of antihypertensives, lipid-lowering agents, and nonsteroidal anti-inflammatory drugs.

CONCLUSIONS

Age and sex are the most important factors determining therapeutic drug use. Lifestyle patterns and sociocultural factors have an impact only on psychoactive drug use. Diabetes mellitus is associated with greater use of antihypertensives, lipid-lowering agents, and nonsteroidal anti-inflammatory drugs.

Hypertriglyceridemia is associated with development of metabolic glucose disorders, irrespective of glucose and insulin levels: a 15-year follow-up study

BACKGROUND

Because the role of 2-h postload glucose and insulin levels as confounders in the relationship between hypertriglyceridemia and development of metabolic glucose disorders (MGD) has not been elucidated, the aim of this study was to determine whether triglyceride levels ≥ 1.7 mmol/L are a risk factor of developing MGD in otherwise healthy men and women.

METHODS

A total of 341 healthy men and non-pregnant women, 30 to 50 years of age, were enrolled in a 15-year follow-up study and allocated into the exposed (triglycerides ≥ 1.7 mmol/L) and non-exposed (triglycerides <1.7 mmol/L) groups. Follow-up visits were scheduled every 3 years to complete 5 visits (mean 3.8 visits). At final follow-up, about 15 years later (mean 13.6 years), contact was re-established in 236 individuals to complete 3540 person-years of follow-up. At baseline, all subjects in both groups were required to be free of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), IFG+IGT, and type 2 diabetes.

RESULTS

The Poisson regression models, adjusted by age, sex, family history of diabetes, waist circumference, body mass index, total body fat, blood pressure, fasting and postload glucose, fasting and postload insulin, and HOMA-IR index, showed a significant association between triglycerides ≥ 1.7 mmol/L and IFG (relative risk - RR - 1.40; 95% CI 1.2-2.2), IGT (RR 1.60; 95% CI 1.3-2.2), IFG+IGT (RR 1.80; 95% CI 1.5-2.7), and type 2 diabetes (RR 3.0; 95% CI 2.5-3.8).

CONCLUSIONS

Serum triglyceride levels ≥ 1.7 mmol/L are an independent risk factor of developing IFG, IGT, IFG+IGT, and type 2 diabetes in young and middle-aged, men and women.

Elevated 1 h postload plasma glucose levels identify adults with normal glucose tolerance but increased risk of non-alcoholic fatty liver disease

OBJECTIVE

To determine the ability of the proposed diagnostic value of a 1-h OGTT glucose ≥155mg/dL to identify individuals with non-alcoholic fatty liver disease (NAFLD) diagnosed by ultrasonography in a cohort of adult white individuals.

DESIGN

The study group comprised 710 white individuals participating to the CATAnzaro MEtabolic RIsk factors (CATAMERI) Study, a cross-sectional study assessing cardio-metabolic risk factors in individuals carrying at least one risk factor including dysglycemia, overweight/obesity, hypertension, dyslipidemia. a 75 g oral Oral Glucose Tolerance Test (OGTT) was performed with 0, 30, 60, 90 and 120 min sampling for plasma glucose and insulin measurements. Cardio-metabolic risk factors including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase (GGT) were assessed in the whole cohort.

RESULTS

Of the 710 participants examined, 295 had normal glucose tolerance (NGT) with 1-hour post-load plasma glucose <155 mg/dL (NGT 1h-low), 109 individuals had NGT 1h-high, 104 had isolated impaired fasting glucose (IFG), and 202 had impaired glucose tolerance (IGT). As compared with NGT 1h-low, NGT 1h-high and IGT subjects exhibited significantly higher body mass index (BMI), triglycerides, high sensitivity C reactive protein, ALT, GGT, and hepatic insulin resistance (IR), assessed by the liver IR index, as well as lower high density lipoprotein, and insulin-like growth factor-1 (IGF-1) levels. In a logistic regression analysis adjusted for age, gender, and BMI, NGT 1h-high participants had a 1.5-fold increased risk of having NAFLD and an even increased risk was observed in subjects with IGT (1.8-fold), but not in the isolated IFG group (1.01-fold).

CONCLUSIONS

These data suggest that the value of a 1-hour OGTT glucose ≥155 mg/dL may be helpful to identify a subset of NGT individuals at risk for NAFLD.

A meta-analysis of the effect of angiotensin receptor blockers and calcium channel blockers on blood pressure, glycemia and the HOMA-IR index in non-diabetic patients

OBJECTIVE

This study compared the efficacy of angiotensin receptor blockers (ARBs) and calcium channel blockers (CCBs) in the effect of insulin resistance (IR) as assessed using the homeostasis model assessment of insulin resistance (HOMA-IR) in non-diabetic patients.

METHODS

The MEDLINE, EMBASE, and Cochrane Library databases were searched to identify studies published before December 2012 that investigated the use of ARBs and CCBs to determine the effect on the HOMA-IR index in non-diabetics. Parameters on IR and blood pressure were collected. Review Manager 5.2 and Stata 12.0 were used to perform the meta-analysis. Fixed and random effects models were applied to various aspects of the meta-analysis, which assessed the therapeutic effects of the two types of drug using the HOMA-IR index in non-diabetic patients.

RESULTS

The meta-analysis included five clinical trials. Patient comparisons before and after treatment with ARBs and CCBs revealed that ARBs reduced the HOMA-IR index (weighted mean difference (WMD) -0.65, 95% confidence interval (CI) -0.93 to -0.38) and fasting plasma insulin (FPI) (WMD -2.01, 95% CI -3.27 to -0.74) significantly more than CCBs. No significant differences in the therapeutic effects of these two types of drug on blood pressure were observed.

CONCLUSION

Given that there are no significant differences in the therapeutic effects of ARBs and CCBs on blood pressure, as ARBs are superior to CCBs in their effect on the HOMA-IR index in non-diabetics, they might be a better choice in hypertension patients without diabetes.

A refined-JinQi-JiangTang tablet ameliorates prediabetes by reducing insulin resistance and improving beta cell function in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Refined-JQ (JQ-R) is a mixture of refined extracts from three major herbal components of JinQi-JiangTang tablet: Coptis chinensis (Ranunculaceae), Astragalus membranaceus (Leguminosae), and Lonicera japonica (Caprifoliaceae). Our previous studies have indicated that JQ-R could decrease fasting blood glucose levels in diabetic mice and insulin resistance mice. Investigating the hypoglycemic effect of JQ-R on prediabetes has practical application value for preventing or delaying insulin resistance, impaired glucose tolerance and possibly the development of clinical diabetes.

MATERIALS AND METHODS

The anti-diabetic potential of JQ-R was investigated using a high fat-diet (HFD)-induced obesity mouse model. C57BL/6J mice (HFD-C57 mice) were fed with high-fat diet for 4 months. HFD-C57 mice were treated with either JQ-R (administered intragastrically once daily for 4 weeks) or metformin (as positive control), and the effects of JQ-R on body weight, blood lipids, glucose metabolism, insulin sensitivity, and beta cell function were monitored.

RESULTS

The body weight, serum cholesterol, and the Homeostasis Model Assessment ratio (insulin resistance index) were significantly reduced in JQ-R or metformin-treated mice, and the glucose tolerance was enhanced and insulin response was improved simultaneously. Moreover, both JQ-R and metformin could activate liver glycogen syntheses even under a relatively high glucose loading. Although glyconeogenesis was inhibited in the metformin treated mice, it was not observed in JQ-R treated mice. Similar to metformin, JQ-R could also improve the glucose infusion rate (GIR) in hyperglycemic clamp test. JQ-R was also shown to increase the levels of phosphorylated AMPKα and phosphorylated acetyl CoA carboxylase (ACC), similar to metformin.

CONCLUSION

JQ-R could reduce HFD-induced insulin resistance by regulating glucose and lipid metabolism, increasing insulin sensitivity through activating the AMPK signaling pathway, and subsequently improving β cell function. Therefore, JQ-R may offer an alternative in treating disorders associated with insulin resistance, such as prediabetes and T2DM.

The serum level of soluble CD26/dipeptidyl peptidase 4 increases in response to acute hyperglycemia after an oral glucose load in healthy subjects: association with high-molecular weight adiponectin and hepatic enzymes

A soluble form of CD26/dipeptidyl peptidase 4 (sCD26/DPP4) is found in serum and it has DPP4 enzymatic activity. We investigated whether the serum level of sCD26/DPP4 was influenced by the oral glucose tolerance test (OGTT) in healthy subjects. The serum sCD26/DPP4 level increased significantly from 824.5 ng/mL (interquartile range, from 699.0 to 1050 ng/mL) at baseline to a peak of 985.0 ng/mL (interquartile range, from 796.5 to 1215 ng/mL) during the OGTT (P < 0.0001). The peak sCD26/DPP4 level correlated positively with the baseline age and body mass index, and fasting plasma glucose (FPG), homeostasis model assessment of insulin resistance (HOMA-IR), triglycerides (TG), alanine aminotransferase, and γ-glutamyl transpeptidase (GGT) levels whereas it correlated negatively with high-density lipoprotein (HDL) cholesterol and the serum levels of total and high-molecular weight (HMW) adiponectin. Stepwise regression analysis was done with forward selection of variables, including age, FPG, HOMA-IR, TG, HDL cholesterol, uric acid, GGT, C-reactive protein, and HMW adiponectin. In a model that explained 57.5% of the variation of the peak sCD26/DPP4 level, GGT (β = 0.382, P = 0.007) and HOMA-IR (β = 0.307, P = 0.034) were independent determinants of the peak serum level of sCD26/DPP4. Serum HMW adiponectin decreased significantly from 4.43 μg/mL (interquartile range, from 2.80 to 6.65 μg/mL) at baseline to 4.17 μg/mL (interquartile range, from 2.48 to 6.96 μg/mL) 120 minutes after the oral glucose load (P < 0.0001). The baseline serum level of sCD26/DPP4 showed a significant negative correlation with the percent change of HMW adiponectin during the OGTT. In conclusion, the serum level of sCD26/DPP4 increased acutely after an oral glucose load in apparently healthy subjects. The abrupt increase of serum sCD26/DPP4 after a glucose load may be a marker of insulin resistance that could come from liver or muscle.

Serum osteocalcin is associated with improved metabolic state via adiponectin in females versus testosterone in males. Gender specific nature of the bone-energy homeostasis axis

OBJECTIVE

The osteoblast-derived protein osteocalcin (OCN) is known to be involved in glucose metabolism by increasing adiponectin secretion from adipocytes. Recently, OCN was also found to enhance testosterone production in mouse testes, suggesting that OCN effects on energy metabolism may be mediated through testosterone. Our aim was to assess a possible gender difference in the metabolic effect of OCN in humans.

METHODS

We included 135 women and 155 men exhibiting changes in glucose tolerance in our study. Oral and intravenous glucose tolerance tests (OGTT and IVGTT, respectively) and a hyperinsulinemic normoglycemic clamp were performed. For clamp indices, whole body (M1) and muscle (M2) glucose uptake values were used. Leptin, adiponectin serum lipid, lipoprotein, total serum OCN and testosterone levels, and body composition were determined.

RESULTS

Higher OCN values were associated with improving metabolic state in both genders. Adiponectin and OCN correlated significantly only in females (r=+0.254, p=0.0029), while in men, testosterone and OCN values showed a significant positive correlation (r=+0.243, p=0.0023), independent of age, BMI, HbA1c and body composition. In women, adiponectin was confirmed by feature selection analysis as being an independent determinant of OCN, in addition to age and three of the IVGTT glucose values. In men, besides M1, BMI, M2, leptin, body fat percent, and the 90-minute OGTT glucose reading testosterone, but not adiponectin were identified as independent contributors for OCN.

CONCLUSION

We confirmed the 'classic' adiponectin-mediated insulin-sensitising effect of OCN only in females. In men, a testosterone-mediated OCN metabolic effect is more likely.

Inflammatory cytokines and chemokines, skeletal muscle and polycystic ovary syndrome: effects of pioglitazone and metformin treatment

OBJECTIVE

Chronic low-grade inflammation is a common feature of insulin resistant states, including obesity and type 2 diabetes. Less is known about inflammation in Polycystic Ovary Syndrome (PCOS). Thus we evaluated the impact of PCOS on circulating cytokine levels and the effects of anti-diabetic therapies on insulin action, cytokine and chemokine levels and inflammatory signaling in skeletal muscle.

METHODS

Twenty subjects with PCOS and 12 healthy normal cycling (NC) subjects of similar body mass index were studied. PCOS subjects received oral placebo or pioglitazone, 45 mg/d, for 6 months. All PCOS subjects then had metformin, 2 g/day, added to their treatment. Circulating levels of cytokines, chemokines, and adiponectin, skeletal muscle markers of inflammation and phosphorylation of signaling proteins, insulin action evaluated by the hyperinsulinemic/euglycemic clamp procedure and Homeostasis Model Assessment of Insulin Resistance were measured.

RESULTS

Circulating levels of a number of cytokines and chemokines were generally similar between PCOS and NC subjects. Levels in PCOS subjects were not altered by pioglitazone or metformin treatment, even though whole body insulin action and adiponectin levels increased with pioglitazone. In spite of the lack of change in levels of cytokines and chemokines, several markers of inflammation in skeletal muscle were improved with Pio treatment.

CONCLUSIONS

PCOS may represent a state of elevated sensitivity of inflammatory cells in skeletal muscle to cytokines and chemokines, a property that could be reversed by pioglitazone treatment together with improved insulin action.

Depressive symptoms and metabolic markers of risk for type 2 diabetes in obese adolescents

OBJECTIVE

Although higher rates of depression are found among individuals with type 2 diabetes, it remains unknown if the presence of depressive symptoms is associated with heightened metabolic risk for the development of type 2 diabetes among youth. The objective of this study was to evaluate whether depressive symptoms in obese adolescents are associated with impaired β-cell function relative to insulin sensitivity [oral disposition index (oDI)] and/or dysglycemia or prediabetes, predictors of type 2 diabetes development.

RESEARCH DESIGN AND METHODS

Fasting and oral glucose tolerance test (OGTT)-derived indices of glucose tolerance, insulin sensitivity, secretion, and oDI were evaluated in obese youth (n = 56, age 15.0 ± 1.6 yr, 68% female). The Children's Depression Inventory was utilized to determine depressive symptomatology.

RESULTS

Despite no association between depressive symptoms and measures of adiposity, youth with higher depressive symptoms had (i) significantly higher fasting and stimulated glucose levels (13% higher glucose area under the OGTT curve), (ii) ∼50% lower oDI, and (iii) a 50% frequency of prediabetes.

CONCLUSIONS

These data point to an important relationship between depressive symptoms and a heightened metabolic risk for type 2 diabetes in obese adolescents, including prediabetes and impairment in β-cell function relative to insulin sensitivity. While the directionality of these relationships is unknown, it should be determined if treating one disorder improves the other or vice versa.

Prognostic association of HbA1c and fasting plasma glucose with reduced kidney function in subjects with and without diabetes mellitus. Results from a population-based cohort study from Germany

OBJECTIVE

To determine the risk for incident reduced kidney function (RKF) of subjects with pre-diabetes (impaired fasting glucose (IFG, 5.6-6.9 mmol/L)) or HbA1c-defined pre-diabetes (5.7%-6.4%) and to determine dose-response relationships of fasting glucose and HbA1c with RKF in subjects with manifest diabetes mellitus.

METHOD

In a German population-based cohort, recruited 2000-2002 with ages 50-74 years, log-binomial regression was used to estimate relative risks (RR) with 95% confidence intervals (95%CI) and restricted cubic splines to plot dose-response relationships.

RESULTS

During 8 years of follow-up, 678 of 3538 study participants developed primary RKF. Although RKF risk factor prevalences and RKF incidences were higher in subjects with pre-diabetes than in subjects with normal FPG and/or HbA1c levels, an increased risk did not persist after adjusting for established cardiovascular risk factors (RR(IFG): 0.97 (95% CI: 0.75-1.25) and RR(HbA1c-defined pre-diabetes): 1.03 (95% CI: 0.86-1.23)). In subjects with manifest diabetes, RKF risk increased linearly to a more than three-fold risk with increasing fasting glucose and HbA1c levels (at HbA1c>6.4%).

CONCLUSION

This study provides further evidence that pre-diabetes may not directly contribute to the development of kidney disease. Subjects with pre-diabetes might nevertheless profit from preventive efforts reducing their cardiovascular risk profile because cardiovascular and kidney disease share common risk factors.

The combination of GIP plus xenin-25 indirectly increases pancreatic polypeptide release in humans with and without type 2 diabetes mellitus

Xenin-25 (Xen) is a 25-amino acid neurotensin-related peptide that activates neurotensin receptor-1 (NTSR1). We previously showed that Xen increases the effect of glucose-dependent insulinotropic polypeptide (GIP) on insulin release 1) in hyperglycemic mice via a cholinergic relay in the periphery independent from the central nervous system and 2) in humans with normal or impaired glucose tolerance, but not type 2 diabetes mellitus (T2DM). Since this blunted response to Xen defines a novel defect in T2DM, it is important to understand how Xen regulates islet physiology. On separate visits, subjects received intravenous graded glucose infusions with vehicle, GIP, Xen, or GIP plus Xen. The pancreatic polypeptide response was used as an indirect measure of cholinergic input to islets. The graded glucose infusion itself had little effect on the pancreatic polypeptide response whereas administration of Xen equally increased the pancreatic polypeptide response in humans with normal glucose tolerance, impaired glucose tolerance, and T2DM. The pancreatic polypeptide response to Xen was similarly amplified by GIP in all 3 groups. Antibody staining of human pancreas showed that NTSR1 is not detectable on islet endocrine cells, sympathetic neurons, blood vessels, or endothelial cells but is expressed at high levels on PGP9.5-positive axons in the exocrine tissue and at low levels on ductal epithelial cells. PGP9.5 positive nerve fibers contacting beta cells in the islet periphery were also observed. Thus, a neural relay, potentially involving muscarinic acetylcholine receptors, indirectly increases the effects of Xen on pancreatic polypeptide release in humans.