Surrogate measures of first-phase insulin secretion versus reference methods intravenous glucose tolerance test and hyperglycemic clamp: a systematic review and meta-analyses.

INTRODUCTION: In this systematic review, we investigated the diagnostic accuracy of surrogate measures of insulin secretion based on fasting samples and the oral glucose tolerance test (OGTT). The first phase of insulin secretion was calculated using two gold standard methods; the hyperglycemic clamp (HGC) test and intravenous glucose tolerance test (IVGTT). RESEARCH DESIGN AND METHODS: We conducted searches in the PubMed, Cochrane Central, and Web of Science databases, the last of which was conducted at the end of June 2021. Studies were included that measured first-phase insulin secretion in adults using both a gold-standard reference method (either HGC or IVGTT) and one or more surrogate measures from either fasting samples, OGTT or a meal-tolerance test. QUADAS-2, a revised tool for the quality assessment of diagnostic accuracy studies, was used for quality assessment. Random-effects meta-analyses were performed to examine the correlation between first-phase measured with gold standard and surrogate methods. RESULTS: A total of 33 articles, encompassing 5362 individuals with normal glucose tolerance, pre-diabetes or type 2 diabetes, were included in our systematic review. Homeostatic model assessment (HOMA)-beta and Insulinogenic Index 30 (IGI(30)) were the surrogate measures validated in the largest number of studies (17 and 13, respectively). HOMA-beta's pooled correlation to the reference methods was 0.48 (95% CI 0.40 to 0.56) The pooled correlation of IGI to the reference methods was 0.61 (95% CI 0.54 to 0.68). The surrogate measures with the highest correlation to the reference methods were Kadowaki (0.67 (95% CI 0.61 to 0.73)) and Stumvoll's first-phase secretion (0.65 (95% CI 0.58 to 0.71)), both calculated from an OGTT. CONCLUSIONS: Surrogate measures from the first 30 min of an OGTT capture the first phase of insulin secretion and are a good choice for epidemiological studies. HOMA-beta has a moderate correlation to the reference methods but is not a measure of the first phase specifically. PROSPERO REGISTRATION NUMBER: The meta-analysis was registered at PROSPERO (Id: CRD42020169064) before inclusion started.

Awareness of cardiovascular risk among persons with type 2 diabetes: a qualitative study.

PURPOSE: To describe the process of becoming aware of and acting on personal cardiovascular (CVD) risk in type 2 diabetes (T2D). METHOD: A purposive sample of 14 persons living with T2D participated in semi-structured, open-ended, in-dept interviews. The interviews were analysed with grounded theory. RESULT: The analysis identified the core category "Balancing emotions, integrating knowledge and understanding to achieve risk awareness and act on it." Five categories describe the movement from not being aware of the risk of cardiovascular disease (CVD) to becoming aware of this risk and taking action to reduce it. Persons with T2D need to transform their knowledge and experience of CVD risk and incorporate it in their individual situations. Emotional and existential experiences of CVD risk can lead to awareness about the severity of the condition and contribute to increased motivation for self-management. However, an overly high emotional response can be overwhelming and may result in insufficient self-management. CONCLUSION: Persons with T2D seemed not to fully grasp their increased risk of CVD or recognize that self-management activities were aimed at reducing this risk. However, their awareness of CVD risk gradually increased as they came to understand the severity of T2D and became more emotionally and existentially engaged.

Prevalence of atherosclerosis in individuals with prediabetes and diabetes compared to normoglycaemic individuals-a Swedish population-based study.

BACKGROUND: Patients with type 2 diabetes have an increased risk of death and cardiovascular events and people with diabetes or prediabetes have been found to have increased atherosclerotic burden in the coronary and carotid arteries. This study will estimate the cross-sectional prevalence of atherosclerosis in the coronary and carotid arteries in individuals with prediabetes and diabetes, compared with normoglycaemic individuals in a large population-based cohort. METHODS: The 30,154 study participants, 50-64 years, were categorized according to their fasting glycaemic status or self-reported data as normoglycaemic, prediabetes, and previously undetected or known diabetes. Prevalence of affected coronary artery segments, severity of stenosis and coronary artery calcium score (CACS) were determined by coronary computed tomography angiography. Total atherosclerotic burden was assessed in the 11 clinically most relevant segments using the Segment Involvement Score and as the presence of any coronary atherosclerosis. The presence of atherosclerotic plaque in the carotid arteries was determined by ultrasound examination. RESULTS: Study participants with prediabetes (n = 4804, 16.0%) or diabetes (n = 2282, 7.6%) had greater coronary artery plaque burden, more coronary stenosis and higher CACS than normoglycaemic participants (all, p < 0.01). Among male participants with diabetes 35.3% had CACS ≥ 100 compared to 16.1% among normoglycaemic participants. For women, the corresponding figures were 8.9% vs 6.1%. The prevalence of atherosclerosis in the coronary arteries was higher in participants with previously undetected diabetes than prediabetes, but lower than in patients with known diabetes. The prevalence of any plaque in the carotid arteries was higher in participants with prediabetes or diabetes than in normoglycaemic participants. CONCLUSIONS: In this large population-based cohort of currently asymptomatic people, the atherosclerotic burden in the coronary and carotid arteries increased with increasing degree of dysglycaemia. The finding that the atherosclerotic burden in the coronary arteries in the undetected diabetes category was midway between the prediabetes category and patients with known diabetes may have implications for screening strategies and tailored prevention interventions for people with dysglycaemia in the future.

Experiences of transition to adulthood and transfer to adult care in young adults with type 1 diabetes: A qualitative study.

AIM: To explore young adults' experiences of living with type 1 diabetes in the transition to adulthood, including experiences of the transfer from paediatric to adult care. DESIGN: A qualitative approach was used. METHOD: Ten young adults, six women and four men, aged 19-29 years, participated. Participants were recruited at their regular diabetes clinic from spring 2021 to spring 2022. Semi-structured interviews were transcribed and analysed using qualitative content analysis. FINDINGS: Dreaming of being nurtured towards self-reliance was the overarching theme. Personal experiences of the transition to adulthood, including the transfer from paediatric to adult care, were described in terms of struggling to find balance in daily life, dealing with feelings of being different, being gradually supported to achieve independence, and wishing to be approached as a unique person in healthcare. CONCLUSION: In healthcare, it is important to emphasize not only diabetes-related factors but also emotional and psychosocial aspects of life connected to the transition to adulthood, including the transfer to adult care. The young adults wished to be seen as unique persons in healthcare during their emerging adulthood and should therefore be supported to achieve self-reliance through personal preparations for new challenges and for the consequences of transitioning to adulthood. Specialist nurses can provide appropriate knowledge and leadership. IMPLICATIONS FOR THE PROFESSION: These findings can guide nurse specialists in support for emerging adults to achieve self-reliance and indicate the importance of person-centred care when experiencing transition and transfer. REPORTING METHOD: The study adhered to EQUATOR guidelines, and the COREQ checklist for qualitative studies was used as the reporting method.

Comprehensive validation of fasting-based and oral glucose tolerance test-based indices of insulin secretion against gold standard measures.

INTRODUCTION: With pre-diabetes and diabetes increasingly recognized as heterogeneous conditions, assessment of beta-cell function is gaining clinical importance to identify disease subphenotypes. Our study aims to comprehensively validate all types of surrogate indices based on oral glucose tolerance test (OGTT) and fasting measurements in comparison with gold standard methods. RESEARCH DESIGN AND METHODS: The hyperglycemic clamp extended with glucagon-like peptide 1 (GLP-1) infusion and intravenous glucose tolerance test (IVGTT), as well as OGTT, was performed in two well-phenotyped cohorts. The gold standard-derived indices were compared with surrogate insulin secretion markers, derived from fasting state and OGTT, using both Pearson's and Spearman's correlation coefficients. The insulin-based and C-peptide-based indices were analyzed separately in different groups of glucose tolerance and the entire cohorts. RESULTS: The highest correlation coefficients were found for area under curve (AUC) (I0-30)/AUC (G0-30), I30/G30, first-phase Stumvoll and Kadowaki model. These indices have high correlation coefficients with measures obtained from both insulin and C-peptide levels from IVGTT and hyperglycemic clamp. AUC (I0-120)/AUC (G0-120), BIGTT-AIR0-60-120, I30/G30, first-phase Stumvoll and AUC (I0-30)/AUC (G0-30) demonstrated the strongest association with incretin-stimulated insulin response. CONCLUSIONS: We have identified glucose-stimulated and GLP-1-stimulated insulin secretion indices, derived from OGTT and fasting state, that have the strongest correlation with gold standard measures and could be potentially used in future researches and clinical practice.

Distinctive exercise-induced inflammatory response and exerkine induction in skeletal muscle of people with type 2 diabetes.

Mechanistic insights into the molecular events by which exercise enhances the skeletal muscle phenotype are lacking, particularly in the context of type 2 diabetes. Here, we unravel a fundamental role for exercise-responsive cytokines (exerkines) on skeletal muscle development and growth in individuals with normal glucose tolerance or type 2 diabetes. Acute exercise triggered an inflammatory response in skeletal muscle, concomitant with an infiltration of immune cells. These exercise effects were potentiated in type 2 diabetes. In response to contraction or hypoxia, cytokines were mainly produced by endothelial cells and macrophages. The chemokine CXCL12 was induced by hypoxia in endothelial cells, as well as by conditioned medium from contracted myotubes in macrophages. We found that CXCL12 was associated with skeletal muscle remodeling after exercise and differentiation of cultured muscle. Collectively, acute aerobic exercise mounts a noncanonical inflammatory response, with an atypical production of exerkines, which is potentiated in type 2 diabetes.

Oral glucose tolerance testing as a complement to fasting plasma glucose in screening for type 2 diabetes: population-based cross-sectional analyses of 146 000 health examinations in Västerbotten, Sweden.

OBJECTIVE: To assess the effect of adding an oral glucose tolerance test (OGTT) to fasting plasma glucose (FPG) in terms of detection of type 2 diabetes (T2D) and impaired glucose tolerance (IGT). DESIGN: Retrospective analysis of serial cross-sectional screening study. SETTING: Population-based health examinations within primary care in Västerbotten County, Sweden. PARTICIPANTS: Individuals aged 40- 50 and 60 years with participation from 1985 to 2017. Those with previously diagnosed diabetes and FPG≥7 mmol/L were excluded. PRIMARY AND SECONDARY OUTCOME MEASURES: Prevalence of hyperglycaemia on the OGTT (IGT and T2D defined as 2-hour postload capillary plasma glucose of 8.9-12.1 mmol/L and ≥12.2 mmol/L, respectively). Analyses were further stratified by age, sex and risk factor burden to identify groups at high or low risk of IGT and T2D on testing. The numbers needed to screen (NNS) to prevent one case of T2D through detection and treatment of IGT was estimated, combining prevalence numbers with average progression rates and intervention effects from previous meta-analyses. RESULTS: The prevalence of IGT ranged from 0.9% (95% CI 0.7% to 1.1%) to 29.6% (95% CI 27.4% to 31.7%), and the prevalence of T2D ranged from 0.06% (95% CI 0.02% to 0.11%) to 7.0% (95% CI 5.9% to 8.3%), depending strongly on age, sex and risk factor burden. The estimated NNS to prevent one case of T2D through detection and lifestyle treatment of IGT ranged from 1332 among 40-year-old men without risk factors, to 39 among 60-year-old women with all risk factors combined. CONCLUSIONS: The prevalence of hyperglycaemia on OGTT is highly dependent on age, sex and risk factor burden; OGTT should be applied selectively to high-risk groups to avoid unnecessary testing in the general population.

Fasting C-peptide at type 2 diabetes diagnosis is an independent risk factor for total and cancer mortality.

AIMS: We assessed the association between insulin resistance and blood glucose concentrations at type 2 diabetes diagnosis and future development of diabetes-related complications and mortality. MATERIALS AND METHODS: This retrospective cohort study included 864 individuals with type 2 diabetes (median age 60 years) whose fasting C-peptide and HbA1c were measured at diabetes diagnosis. The median follow-up time until death or study end was 16.4 years (interquartile range 13.3-19.6). The association between C-peptide and mortality/complications was estimated by Cox regression adjusted for sex, age at diabetes diagnosis, smoking, hypertension, BMI, total cholesterol, and HbA1c. C-peptide and HbA1c were converted to Z scores before the Cox regression analysis. RESULTS: An increase by one standard deviation in fasting C-peptide at diabetes diagnosis was associated with all-cause (hazard ratio [HR] 1.33; 95% confidence intervals [CI] 1.12-1.58; p = 0.001) and cancer mortality (HR 1.51; 95% CI 1.13-2.01; p = 0.005) in the fully adjusted model. An increase by one standard deviation in HbA1c at diabetes diagnosis was associated with all-cause mortality (HR 1.24; 95% CI 1.07-1.44; p = 0.005), major cardiovascular events (HR 1.20; 95% CI 1.04-1.39; p = 0.015), stroke (HR 1.36; 95% CI 1.09-1.70; p = 0.006), and retinopathy (HR 1.54; 95% CI 1.34-1.76; p < 0.0001) in the fully adjusted model. CONCLUSIONS: Fasting C-peptide at type 2 diabetes diagnosis is an independent risk factor for total and cancer-related mortality. Thus, treatment of type 2 diabetes should focus not only on normalising blood glucose levels but also on mitigating insulin resistance.

Improved Peripheral and Hepatic Insulin Sensitivity after Lifestyle Interventions in Type 2 Diabetes Is Associated with Specific Metabolomic and Lipidomic Signatures in Skeletal Muscle and Plasma.

Lifestyle interventions with weight loss can improve insulin sensitivity in type 2 diabetes (T2D), but mechanisms are unclear. We explored circulating and skeletal muscle metabolite signatures of altered peripheral (pIS) and hepatic insulin sensitivity (hIS) in overweight and obese T2D individuals that were randomly assigned a 12-week Paleolithic-type diet with (diet-ex, n = 13) or without (diet, n = 13) supervised exercise. Baseline and post-intervention measures included: mass spectrometry-based metabolomics and lipidomics of skeletal muscle and plasma; pIS and hIS; ectopic lipid deposits in the liver and skeletal muscle; and skeletal muscle fat oxidation rate. Both groups lowered BMI and total % fat mass and increased their pIS. Only the diet-group improved hIS and reduced ectopic lipids in the liver and muscle. The combined improvement in pIS and hIS in the diet-group were associated with decreases in muscle and circulating branched-chain amino acid (BCAA) metabolites, specifically valine. Improved pIS with diet-ex was instead linked to increased diacylglycerol (34:2) and triacylglycerol (56:0) and decreased phosphatidylcholine (34:3) in muscle coupled with improved muscle fat oxidation rate. This suggests a tissue crosstalk involving BCAA-metabolites after diet intervention with improved pIS and hIS, reflecting reduced lipid influx. Increased skeletal muscle lipid utilization with exercise may prevent specific lipid accumulation at sites that perturb insulin signaling.

The liver-alpha-cell axis after a mixed meal and during weight loss in type 2 diabetes.

OBJECTIVE: Glucagon and amino acids may be regulated in a feedback loop called the liver-alpha-cell axis with alanine or glutamine as suggested signal molecules. We assessed this concept in individuals with type 2 diabetes in the fasting state, after ingestion of a protein-rich meal, and during weight loss. Moreover, we investigated if postprandial glucagon secretion and hepatic insulin sensitivity were related. METHODS: This is a secondary analysis of a 12-week weight-loss trial (Paleolithic diet ± exercise) in 29 individuals with type 2 diabetes. Before and after the intervention, plasma glucagon and amino acids were measured in the fasting state and during 180 min after a protein-rich mixed meal. Hepatic insulin sensitivity was measured using the hyperinsulinemic-euglycemic clamp with [6,6-2H2]glucose as a tracer. RESULTS: The postprandial increase of plasma glucagon was associated with the postprandial increase of alanine and several other amino acids but not glutamine. In the fasted state and after the meal, glucagon levels were negatively correlated with hepatic insulin sensitivity (rS = -0.51/r = -0.58, respectively; both P < 0.05). Improved hepatic insulin sensitivity with weight loss was correlated with decreased postprandial glucagon response (r = -0.78; P < 0.001). CONCLUSIONS: Several amino acids, notably alanine, but not glutamine could be key signals to the alpha cell to increase glucagon secretion. Amino acids may be part of a feedback mechanism as glucagon increases endogenous glucose production and ureagenesis in the liver. Moreover, postprandial glucagon secretion seems to be tightly related to hepatic insulin sensitivity.

Structural Analysis of a Genetically Encoded FRET Biosensor by SAXS and MD Simulations.

Inspired by the modular architecture of natural signaling proteins, ligand binding proteins are equipped with two fluorescent proteins (FPs) in order to obtain Förster resonance energy transfer (FRET)-based biosensors. Here, we investigated a glucose sensor where the donor and acceptor FPs were attached to a glucose binding protein using a variety of different linker sequences. For three resulting sensor constructs the corresponding glucose induced conformational changes were measured by small angle X-ray scattering (SAXS) and compared to recently published single molecule FRET results (Höfig et al., ACS Sensors, 2018). For one construct which exhibits a high change in energy transfer and a large change of the radius of gyration upon ligand binding, we performed coarse-grained molecular dynamics simulations for the ligand-free and the ligand-bound state. Our analysis indicates that a carefully designed attachment of the donor FP is crucial for the proper transfer of the glucose induced conformational change of the glucose binding protein into a well pronounced FRET signal change as measured in this sensor construct. Since the other FP (acceptor) does not experience such a glucose induced alteration, it becomes apparent that only one of the FPs needs to have a well-adjusted attachment to the glucose binding protein.

Using a Paleo Ratio to Assess Adherence to Paleolithic Dietary Recommendations in a Randomized Controlled Trial of Individuals with Type 2 Diabetes.

This study is a secondary analysis of a randomized controlled trial using Paleolithic diet and exercise in individuals with type 2 diabetes. We hypothesized that increased adherence to the Paleolithic diet was associated with greater effects on blood pressure, blood lipids and HbA1c independent of weight loss. Participants were asked to follow a Paleolithic diet for 12 weeks and were randomized to supervised exercise or general exercise recommendations. Four-day food records were analyzed, and food items characterized as "Paleolithic" or "not Paleolithic". Foods considered Paleolithic were lean meat, poultry, fish, seafood, fruits, nuts, berries, seeds, vegetables, and water to drink; "not Paleolithic" were legumes, cereals, sugar, salt, processed foods, and dairy products. A Paleo ratio was calculated by dividing the Paleolithic calorie intake by total calorie intake. A multiple regression model predicted the outcome at 12 weeks using the Paleo ratio, group affiliation, and outcome at baseline as predictors. The Paleo ratio increased from 28% at baseline to 94% after the intervention. A higher Paleo ratio was associated with lower fat mass, BMI, waist circumference, systolic blood pressure, and serum triglycerides at 12 weeks, but not with lower HbA1c levels. The Paleo ratio predicted triglyceride levels independent of weight loss (p = 0.046). Moreover, an increased monounsaturated/saturated fatty acids ratio and an increased polyunsaturated/saturated fatty acids ratio was associated with lower triglyceride levels independent of weight loss. (p = 0.017 and p = 0.019 respectively). We conclude that a higher degree of adherence to the Paleolithic diet recommendations improved fat quality and was associated with improved triglyceride levels independent of weight loss among individuals with type 2 diabetes.

Association between nutritional profiles of foods underlying Nutri-Score front-of-pack labels and mortality: EPIC cohort study in 10 European countries.

OBJECTIVE: To determine if the Food Standards Agency nutrient profiling system (FSAm-NPS), which grades the nutritional quality of food products and is used to derive the Nutri-Score front-of-packet label to guide consumers towards healthier food choices, is associated with mortality. DESIGN: Population based cohort study. SETTING: European Prospective Investigation into Cancer and Nutrition (EPIC) cohort from 23 centres in 10 European countries. PARTICIPANTS: 521 324 adults; at recruitment, country specific and validated dietary questionnaires were used to assess their usual dietary intakes. A FSAm-NPS score was calculated for each food item per 100 g content of energy, sugars, saturated fatty acids, sodium, fibre, and protein, and of fruit, vegetables, legumes, and nuts. The FSAm-NPS dietary index was calculated for each participant as an energy weighted mean of the FSAm-NPS score of all foods consumed. The higher the score the lower the overall nutritional quality of the diet. MAIN OUTCOME MEASURE: Associations between the FSAm-NPS dietary index score and mortality, assessed using multivariable adjusted Cox proportional hazards regression models. RESULTS: After exclusions, 501 594 adults (median follow-up 17.2 years, 8 162 730 person years) were included in the analyses. Those with a higher FSAm-NPS dietary index score (highest versus lowest fifth) showed an increased risk of all cause mortality (n=53 112 events from non-external causes; hazard ratio 1.07, 95% confidence interval 1.03 to 1.10, P<0.001 for trend) and mortality from cancer (1.08, 1.03 to 1.13, P<0.001 for trend) and diseases of the circulatory (1.04, 0.98 to 1.11, P=0.06 for trend), respiratory (1.39, 1.22 to 1.59, P<0.001), and digestive (1.22, 1.02 to 1.45, P=0.03 for trend) systems. The age standardised absolute rates for all cause mortality per 10 000 persons over 10 years were 760 (men=1237; women=563) for those in the highest fifth of the FSAm-NPS dietary index score and 661 (men=1008; women=518) for those in the lowest fifth. CONCLUSIONS: In this large multinational European cohort, consuming foods with a higher FSAm-NPS score (lower nutritional quality) was associated with a higher mortality for all causes and for cancer and diseases of the circulatory, respiratory, and digestive systems, supporting the relevance of FSAm-NPS to characterise healthier food choices in the context of public health policies (eg, the Nutri-Score) for European populations. This is important considering ongoing discussions about the potential implementation of a unique nutrition labelling system at the European Union level.

The associations of major foods and fibre with risks of ischaemic and haemorrhagic stroke: a prospective study of 418 329 participants in the EPIC cohort across nine European countries.

AIM: To investigate the associations between major foods and dietary fibre with subtypes of stroke in a large prospective cohort. METHODS AND RESULTS: We analysed data on 418 329 men and women from nine European countries, with an average of 12.7 years of follow-up. Diet was assessed using validated country-specific questionnaires which asked about habitual intake over the past year, calibrated using 24-h recalls. Multivariable-adjusted Cox regressions were used to estimate hazard ratios (HRs) for ischaemic and haemorrhagic stroke associated with consumption of red and processed meat, poultry, fish, dairy foods, eggs, cereals, fruit and vegetables, legumes, nuts and seeds, and dietary fibre. For ischaemic stroke (4281 cases), lower risks were observed with higher consumption of fruit and vegetables combined (HR; 95% CI per 200 g/day higher intake, 0.87; 0.82-0.93, P-trend < 0.001), dietary fibre (per 10 g/day, 0.77; 0.69-0.86, P-trend < 0.001), milk (per 200 g/day, 0.95; 0.91-0.99, P-trend = 0.02), yogurt (per 100 g/day, 0.91; 0.85-0.97, P-trend = 0.004), and cheese (per 30 g/day, 0.88; 0.81-0.97, P-trend = 0.008), while higher risk was observed with higher red meat consumption which attenuated when adjusted for the other statistically significant foods (per 50 g/day, 1.07; 0.96-1.20, P-trend = 0.20). For haemorrhagic stroke (1430 cases), higher risk was associated with higher egg consumption (per 20 g/day, 1.25; 1.09-1.43, P-trend = 0.002). CONCLUSION: Risk of ischaemic stroke was inversely associated with consumption of fruit and vegetables, dietary fibre, and dairy foods, while risk of haemorrhagic stroke was positively associated with egg consumption. The apparent differences in the associations highlight the importance of examining ischaemic and haemorrhagic stroke subtypes separately.

Diet-induced weight loss alters hepatic glucocorticoid metabolism in type 2 diabetes mellitus.

CONTEXT: Altered tissue-specific glucocorticoid metabolism has been described in uncomplicated obesity and type 2 diabetes. We hypothesized that weight loss induced by diet and exercise, which has previously been shown to reverse abnormal cortisol metabolism in uncomplicated obesity, also normalizes cortisol metabolism in patients with type 2 diabetes. OBJECTIVE: Test the effects of a diet intervention with added exercise on glucocorticoid metabolism. DESIGN: Two groups followed a Paleolithic diet (PD) for 12 weeks with added 180 min of structured aerobic and resistance exercise per week in one randomized group (PDEX). SETTING: Umeå University Hospital. PARTICIPANTS: Men and women with type 2 diabetes treated with lifestyle modification ± metformin were included. Twenty-eight participants (PD, n = 15; PDEX, n = 13) completed measurements of glucocorticoid metabolism. MAIN OUTCOME MEASURES: Changes in glucocorticoid metabolite levels in 24-h urine samples, expression of HSD11B1 mRNA in s.c. adipose tissue and conversion of orally administered cortisone to cortisol measured in plasma. Body composition and insulin sensitivity were measured using a hyperinsulinemic-euglycemic clamp, and liver fat was measured by magnetic resonance spectroscopy. RESULTS: Both groups lost weight and improved insulin sensitivity. Conversion of orally taken cortisone to plasma cortisol and the ratio of 5α-THF + 5ß-THF/THE in urine increased in both groups. CONCLUSIONS: These interventions caused weight loss and improved insulin sensitivity with concomitant increases in the conversion of cortisone to cortisol, which is an estimate of hepatic HSD11B1 activity. This suggests that dysregulation of liver glucocorticoid metabolism in these patients is a consequence rather than a cause of metabolic dysfunction.

A FRET-based biosensor for the quantification of glucose in culture supernatants of mL scale microbial cultivations.

BACKGROUND: In most microbial cultivations D-glucose is the main carbon and energy source. However, quantification of D-glucose especially in small scale is still challenging. Therefore, we developed a FRET-based glucose biosensor, which can be applied in microbioreactor-based cultivations. This sensor consists of a glucose binding protein sandwiched between two fluorescent proteins, constituting a FRET pair. Upon D-glucose binding the sensor undergoes a conformational change which is translated into a FRET-ratio change. RESULTS: The selected sensor shows an apparent Kd below 1.5 mM D-glucose and a very high sensitivity of up to 70% FRET-ratio change between the unbound and the glucose-saturated state. The soluble sensor was successfully applied online to monitor the glucose concentration in an Escherichia coli culture. Additionally, this sensor was utilized in an at-line process for a Corynebacterium glutamicum culture as an example for a process with cell-specific background (e.g. autofluorescence) and medium-induced quenching. Immobilization of the sensor via HaloTag® enabled purification and covalent immobilization in one step and increased the stability during application, significantly. CONCLUSION: A FRET-based glucose sensor was used to quantify D-glucose consumption in microtiter plate based cultivations. To the best of our knowledge, this is the first method reported for online quantification of D-glucose in microtiter plate based cultivations. In comparison to D-glucose analysis via an enzymatic assay and HPLC, the sensor performed equally well, but enabled much faster measurements, which allowed to speed up microbial strain development significantly.

Postprandial levels of GLP-1, GIP and glucagon after 2 years of weight loss with a Paleolithic diet: a randomised controlled trial in healthy obese women.

Objective To investigate how weight loss by different diets impacts postprandial levels of glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and glucagon. Methods In this single-centre, parallel group 2-year trial, 70 healthy postmenopausal obese women were randomised to the Paleolithic diet or a healthy control diet based on Nordic Nutrition Recommendations. Both diets were without calorie restriction. The primary outcome was the change in fat mass. Here, secondary analyses on GLP-1, GIP and glucagon measured during an OGTT are described. Results In the Paleolithic diet group, mean weight loss compared to baseline was 11% at 6 months and 10% at 24 months. In the control diet group, mean weight loss was 6% after 6 and 24 months (P = 0.0001 and P = 0.049 for the comparison between groups at 6 and 24 months respectively). Compared to baseline, the mean incremental area under the curve (iAUC) for GLP-1 increased by 34 and 45% after 6 and 24 months in the Paleolithic diet group and increased by 59% after 24 months in the control diet group. The mean iAUC for GIP increased only in the Paleolithic diet group. The area under the curve (AUC) for glucagon increased during the first 6 months in both groups. The fasting glucagon increase correlated with the ß-hydroxybutyrate increase. Conclusions Weight loss caused an increase in postprandial GLP-1 levels and a further rise occurred during weight maintenance. Postprandial GIP levels increased only after the Paleolithic diet. Reduced postprandial glucagon suppression may be caused by a catabolic state.

Impact of Molecular Crowding on Translational Mobility and Conformational Properties of Biological Macromolecules.

Effects of molecular crowding on structural and dynamical properties of biological macromolecules do depend on the concentration of crowding agents but also on the molecular mass and the structural compactness of the crowder molecules. By employing fluorescence correlation spectroscopy (FCS), we investigated the translational mobility of several biological macromolecules ranging from 17 kDa to 2.7 MDa. Polyethylene glycol and Ficoll polymers of different molecular masses were used in buffer solutions to mimic a crowded environment. The reduction in translational mobility of the biological tracer molecules was analyzed as a function of crowder volume fractions and was generally more pronounced in PEG as compared to Ficoll solutions. For several crowding conditions, we observed a molecular sieving effect, in which the diffusion coefficient of larger tracer molecules is reduced to a larger extent than predicted by the Stokes-Einstein relation. By employing a FRET-based biosensor, we also showed that a multiprotein complex is significantly compacted in the presence of macromolecular crowders. Importantly, with respect to sensor in vivo applications, ligand concentration determining sensors would need a crowding specific calibration in order to deliver correct cytosolic ligand concentration.

Exercise Training Adds Cardiometabolic Benefits of a Paleolithic Diet in Type 2 Diabetes Mellitus.

Background The accumulation of myocardial triglycerides and remodeling of the left ventricle are common features in type 2 diabetes mellitus and represent potential risk factors for the development of diastolic and systolic dysfunction. A few studies have investigated the separate effects of diet and exercise training on cardiac function, but none have investigated myocardial changes in response to a combined diet and exercise intervention. This 12-week randomized study assessed the effects of a Paleolithic diet, with and without additional supervised exercise training, on cardiac fat, structure, and function. Methods and Results Twenty-two overweight and obese subjects with type 2 diabetes mellitus were randomized to either a Paleolithic diet and standard-care exercise recommendations ( PD ) or to a Paleolithic diet plus supervised exercise training 3 hours per week ( PD - EX ). This study includes secondary end points related to cardiac structure and function, ie, myocardial triglycerides levels, cardiac morphology, and strain were measured using cardiovascular magnetic resonance, including proton spectroscopy, at baseline and after 12 weeks. Both groups showed major favorable metabolic changes. The PD - EX group showed significant decreases in myocardial triglycerides levels (-45%, P=0.038) and left ventricle mass to end-diastolic volume ratio (-13%, P=0.008) while the left ventricle end-diastolic volume and stroke volume increased significantly (+14%, P=0.004 and +17%, P=0.008, respectively). These variables were unchanged in the PD group. Conclusions Exercise training plus a Paleolithic diet reduced myocardial triglycerides levels and improved left ventricle remodeling in overweight/obese subjects with type 2 diabetes mellitus. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 01513798.

Treadmill workstations in office workers who are overweight or obese: a randomised controlled trial.

BACKGROUND: Treadmill workstations that enable office workers to walk on a treadmill while working at their computers might increase physical activity in offices, but long-term effects are unknown. We therefore investigated whether treadmill workstations in offices increased daily walking time. METHODS: We did a randomised controlled trial of healthy office workers who were either overweight or obese. We recruited participants from 13 different companies, which comprised 17 offices, in Umeå, Sweden. We included people who were aged 40-67 years, had sedentary work tasks, and had a body-mass index (BMI) between 25 kg/m2 and 40 kg/m2. After the baseline measurement, we stratified participants by their BMI (25-30 kg/m2 and >30 to 40 kg/m2); subsequently, an external statistician randomly assigned these participants (1:1) to either the intervention group (who received treadmill workstations for optional use) or the control group (who continued to work at their sit-stand desks as usual). Participants in the intervention group received reminders in boosting emails sent out to them at four occasions during the study period. Researchers were masked to group assignment until after analysis of the primary outcome. After the baseline measurement, participants were not masked to group belongings. The primary outcome was total daily walking time at weekdays and weekends, measured at baseline, 2 months, 6 months, 10 months, and 13 months with the accelerometer activPAL (PAL Technologies, Glasgow, UK), which was worn on the thigh of participants for 24 h a day for 7 consecutive days. We used an intention-to-treat approach for our analyses. This trial is registered with ClinicalTrials.gov, number NCT01997970, and is closed to new participants. FINDINGS: Between Nov 1, 2013, and June 30, 2014, a total of 80 participants were recruited and enrolled (n=40 in both the intervention and control groups). Daily walking time during total time awake at weekdays increased between baseline and 13 months by 18 min (95% CI 9 to 26) in the intervention group and 1 min (-7 to 9) in the control group (difference 22 min [95% CI 7 to 37], pinteraction=0·00045); for weekend walking, the change from baseline to 13 months was 5 min (-8 to 18) in the intervention group and 8 min (-5 to 21) in the control group (difference -1 min [-19 to 17]; pinteraction=0·00045). Neither measure met our predetermined primary outcome of 30 min difference in total walking time between the intervention and control group, so the primary outcome of the trial was not met. One adverse event was reported in a participant who accidently stepped on their Achilles tendon. INTERPRETATION: In a sedentary work environment, treadmill workstations result in a statistically significant but smaller-than-expected increase in daily walking time. Future studies need to investigate how increasing physical activity at work might have potentially compensatory effects on non-work activity. FUNDING: Umeå University, the Västerbotten County Council, and the Mayo Clinic Foundation for Research.