Prediabetes: a must to recognise disease state

Dysmetabolism and Neurodegeneration: Trick or Treat?

Accumulating evidence suggests the existence of a strong link between metabolic syndrome and neurodegeneration. Indeed, epidemiologic studies have described solid associations between metabolic syndrome and neurodegeneration, whereas animal models contributed for the clarification of the mechanistic underlying the complex relationships between these conditions, having the development of an insulin resistance state a pivotal role in this relationship. Herein, we review in a concise manner the association between metabolic syndrome and neurodegeneration. We start by providing concepts regarding the role of insulin and insulin signaling pathways as well as the pathophysiological mechanisms that are in the genesis of metabolic diseases. Then, we focus on the role of insulin in the brain, with special attention to its function in the regulation of brain glucose metabolism, feeding, and cognition. Moreover, we extensively report on the association between neurodegeneration and metabolic diseases, with a particular emphasis on the evidence observed in animal models of dysmetabolism induced by hypercaloric diets. We also debate on strategies to prevent and/or delay neurodegeneration through the normalization of whole-body glucose homeostasis, particularly via the modulation of the carotid bodies, organs known to be key in connecting the periphery with the brain.

Distinct Gut Microbiota Induced by Different Fat-to-Sugar-Ratio High-Energy Diets Share Similar Pro-obesity Genetic and Metabolite Profiles in Prediabetic Mice

Various types of diet can lead to type 2 diabetes. The gut microbiota in type 2 diabetic patients are also different. So, two questions arise: whether there are any commonalities between gut microbiota induced by different pro-obese diets and whether these commonalities lead to disease. Here we found that high-energy diets with two different fat-to-sugar ratios can both cause obesity and prediabetes but enrich different gut microbiota. Still, these different gut microbiota have similar genetic and metabolite compositions. The microbial metabolites in common between the diets modulate lipid accumulation and macrophage inflammation in vivo and in vitro. This work suggests that studies that only use 16S rRNA amplicon sequencing to determine how the microbes respond to diet and associate with diabetic state are missing vital information.

Gut microbiota play important roles in host metabolism, especially in diabetes. However, why different diets lead to similar diabetic states despite being associated with different microbiota is not clear. Mice were fed two high-energy diets (HED) with the same energy density but different fat-to-sugar ratios to determine the associations between the microbiota and early-stage metabolic syndrome. The two diets resulted in different microbiota but similar diabetic states. Interestingly, the microbial gene profiles were not significantly different, and many common metabolites were identified, including l-aspartic acid, cholestan-3-ol (5β, 3α), and campesterol, which have been associated with lipogenesis and inflammation. Our study suggests that different metabolic-syndrome-inducing diets may result in different microbiota but similar microbiomes and metabolomes. This suggests that the metagenome and metabolome are crucial for the prognosis and pathogenesis of obesity and metabolic syndrome.

IMPORTANCE Various types of diet can lead to type 2 diabetes. The gut microbiota in type 2 diabetic patients are also different. So, two questions arise: whether there are any commonalities between gut microbiota induced by different pro-obese diets and whether these commonalities lead to disease. Here we found that high-energy diets with two different fat-to-sugar ratios can both cause obesity and prediabetes but enrich different gut microbiota. Still, these different gut microbiota have similar genetic and metabolite compositions. The microbial metabolites in common between the diets modulate lipid accumulation and macrophage inflammation in vivo and in vitro. This work suggests that studies that only use 16S rRNA amplicon sequencing to determine how the microbes respond to diet and associate with diabetic state are missing vital information.

Effects of Lifestyle Modification and Anti-diabetic Medicine on Prediabetes Progress: A Systematic Review and Meta-Analysis

Background: Pre-diabetes is a risk factor for full-blown diabetes; it presents opportunities to prevent the actual diseases. It is therefore essential to identify effective preventive strategies, and to clarify the direction of future research. Methods: PubMed, Embase and Cochrane Central Register of Controlled Trials were searched using key terms (Supplementary Table 1). We applied network meta-analysis to multiple comparisons among various diabetic preventive strategies, including lifestyle and pharmacological interventions; traditional meta-analysis for the synthesis of basal metabolic changes after interventions; and trial sequential analysis for determinations as to whether analysis conclusions meet expectations. Results: We included 32 randomized controlled trials comprising 43,669 patients and 14 interventions in the meta-analysis. Both lifestyle modifications and anti-diabetic medications improved physical conditions, including weight loss, blood glucose, and blood pressure. Network meta-analysis suggested that the progression of diabetes could be delayed to varying degrees by lifestyle and pharmacological interventions, except for angiotensin-converting enzyme inhibitors, statins, sulfonylureas and vitamin D. The risk ratios (RR) [95% credible interval (CrI)] compared with control were: GLP-1RAs 0.28 (0.15, 0.50), Orlistat 0.33 (0.18, 0.55), TZM 0.33 (0.16, 0.63), TZD 0.39 (0.27, 0.53), LST 0.54 (0.32, 0.88), lifestyle 0.58 (0.49, 0.67), LSM 0.62 (0.45, 0.80), GI 0.66 (0.46, 0.88), SU 0.67 (0.40, 1.00), Vitamin D 0.91 (0.59, 1.40), ACEI 0.93 (0.62, 1.40), statins 1.20 (0.84, 1.60). Conclusions: In adults with pre-diabetes, firm evidence supports the notion that lifestyle modifications and metformin reduces the incidence of diabetes with an average of 20% relative risk reduction, while statins increase the relative risk 20%. We found that lifestyle modifications, promising long-term strategies involving three factors (nutrition, exercise, and weight loss) contribute to health by reducing BMI, body weight, waist and hip circumference, systolic and diastolic pressure, fasting, and 2-h postprandial blood glucose, total cholesterol and by increasing HDL. We made this determination using TSA, avoiding further waste of experimental resources.

Effects of caloric restriction on neuropathic pain, peripheral nerve degeneration and inflammation in normometabolic and autophagy defective prediabetic Ambra1 mice

There is a growing interest on the role of autophagy in diabetes pathophysiology, where development of neuropathy is one of the most frequent comorbidities. We have previously demonstrated that neuropathic pain after nerve damage is exacerbated in autophagy-defective heterozygous Ambra1 mice. Here, we show the existence of a prediabetic state in Ambra1 mice, characterized by hyperglycemia, intolerance to glucose and insulin resistance. Thus, we further investigate the hypothesis that prediabetes may account for the exacerbation of allodynia and chronic pain and that counteracting the autophagy deficit may relieve the neuropathic condition. We took advantage from caloric restriction (CR) able to exert a double action: a powerful increase of autophagy and a control on the metabolic status. We found that CR ameliorates neuropathy throughout anti-inflammatory and metabolic mechanisms both in Ambra1 and in WT animals subjected to nerve injury. Moreover, we discovered that nerve lesion represents, per se, a metabolic stressor and CR reinstates glucose homeostasis, insulin resistance, incomplete fatty acid oxidation and energy metabolism. As autophagy inducer, CR promotes and anticipates Schwann cell autophagy via AMP-activated protein kinase (AMPK) that facilitates remyelination in peripheral nerve. In summary, we provide new evidence for the role of autophagy in glucose metabolism and identify in energy depletion by dietary restriction a therapeutic approach in the fight against neuropathic pain.

Healthy and unhealthy dietary patterns are related to pre-diabetes: a case–control study

Pre-diabetes increases the risk of diabetes and CVD. Several studies have investigated the relationship between food intake and pre-diabetes morbidity, but the dietary patterns of pre-diabetes subjects were not taken into consideration. The aim of this study was to determine the relationship between dietary patterns and pre-diabetes. In this regard, 150 pre-diabetic subjects and 150 healthy controls, who attended the diabetes screening centre in Shahreza, Iran, were matched for age group and sex. The weight, height, waist circumference, physical activity, systolic and diastolic blood pressures, and blood glucose levels of all participants were measured. Dietary information was collected using a semi-quantitative FFQ. Using factor analysis, two dietary patterns were identified: the vegetables, fruits and legumes (VFL) dietary pattern and the sweet, solid fat, meat and mayonnaise (SSMM) dietary pattern. Multivariate logistic regression was used to assess the relationship between pre-diabetes and dietary patterns. After adjusting for age, education, physical activity, BMI and energy intake, the VFL dietary pattern was found to be negatively associated with lower pre-diabetes (OR 0·16; 95 % CI 0·10, 0·26). Furthermore, the SSMM dietary pattern was positively associated with pre-diabetes (OR 5·45; 95 % CI 3·22, 9·23). In conclusion, the VFL dietary pattern is inversely related to pre-diabetes, whereas the SSMM dietary pattern is associated with increased risk of pre-diabetes.

Identification of impaired fasting glucose, healthcare utilization and progression to diabetes in the UK using the Clinical Practice Research Datalink (CPRD)

PURPOSE

Few studies have examined patients with prediabetes in usual, "real-world" clinical practice settings. Among patients with impaired fasting glucose (IFG), we aimed to describe the rates of progression to diabetes and to examine the long-term reduction in diabetes risk associated with regression to normoglycemia at 1 year.

METHODS

The UK-based study included 120 055 non-diabetic patients in Clinical Practice Research Datalink from 2001 to 2012 aged 25+ years and with ≥1 fasting plasma glucose (FPG) test between ≥6.1 and <7.0 mmol/l indicating IFG who were followed for progression to diabetes. In a subgroup of 45 167 patients with IFG with subsequent FPG results 1 year later, we assessed the 1-year glycemic status change and estimated the relative hazard of diabetes comparing patients with regression to normoglycemia (IFG-normoglycemia) to those who remained in IFG (IFG-IFG) using a multivariable Cox model.

RESULTS

Among patients with IFG with over 414 649 person-years of follow-up, 52% received a subsequent FPG test, and 10% developed diabetes within 1 year after recognition of IFG. The incidence rate of diabetes was 5.86 (95% CI: 5.78 to 5.93) per 100 person-years. In the subgroup analysis, 31% of these patients remained in IFG, while 53% and 16% converted to normoglycemia or diabetes, respectively. The adjusted hazard ratio of developing diabetes was 0.33 (95% CI: 0.31 to 0.35) comparing IFG-normoglycemia to IFG-IFG.

CONCLUSIONS

IFG is a high-risk state for diabetes. Regression to normoglycemia from IFG strongly reduces the long-term risk of developing diabetes. Our study also shows the feasibility of identifying patients with IFG in the Clinical Practice Research Datalink. Copyright © 2016 John Wiley & Sons, Ltd.

Association between health-related quality of life and impaired glucose metabolism in Iran: the Qazvin Metabolic Diseases Study

AIM

To evaluate the association between health-related quality of life and glucose metabolism status in a study population in Qazvin, Iran.

METHODS

This cross-sectional study was conducted in 1044 people (aged 20-78 years old) between September 2010 and April 2011 in Qazvin, Iran. An oral glucose tolerance test was performed for each participant who had never been diagnosed with diabetes. Participants were characterized as having normal glucose metabolism, pre-diabetes or diabetes according to American Diabetes Association criteria. The short-form 36 questionnaire was used to measure quality of life. Data were analysed using a chi-squared test, anova and ancova.

RESULTS

A total of 530 (51.7%) of the participants were women, and 24.1 and 11.6% of the participants were categorized as having prediabetes and diabetes mellitus, respectively. Except for the role emotional domain, there was a gradual decrease in the mean scores of every domain of the short-form 36 scale across the three study groups. The mean scores in the physical domains were significantly different among the participants with normal glucose metabolism and those with diabetes. After adding age as covariate, there were no significant differences between the categories in any of the domains.

CONCLUSION

There is no association between quality of life domains and glucose metabolism status in Iranian subjects. More longitudinal studies are necessary to investigate the natural history of pre-diabetes, diabetes and quality of life.

Therapeutic interventions to reduce the risk of progression from prediabetes to type 2 diabetes mellitus

Clinical trials have demonstrated that it is possible to prevent diabetes through lifestyle modification, pharmacological intervention, and surgery. This review aims to summarize the effectiveness of these various therapeutic interventions in reducing the risk of progression of prediabetes to diabetes, and address the challenges to implement a diabetes prevention program at a community level. Strategies focusing on intensive lifestyle changes are not only efficient but cost-effective and/or cost-saving. Indeed, lifestyle intervention in people at high risk for type 2 diabetes mellitus (T2DM) has been successful in achieving sustained behavioral changes and a reduction in diabetes incidence even after the counseling is stopped. Although prediabetes is associated with health and economic burdens, it has not been adequately addressed by interventions or regulatory agencies in terms of prevention or disease management. Lifestyle intervention strategies to prevent T2DM should be distinct for different populations around the globe and should emphasize sex, age, ethnicity, and cultural and geographical considerations to be feasible and to promote better compliance. The translation of diabetes prevention research at a population level, especially finding the most effective methods of preventing T2DM in various societies and cultural settings remains challenging, but must be accomplished to stop this worldwide epidemic.

Elevated blood glucose levels in the emergency department: missed opportunities

INTRODUCTION

Prediabetes is an important public health issue. In 2011, 79 million Americans had prediabetes, and 7 million were undiagnosed. By 2025, the number of persons with prediabetes is projected to increase to 472 million globally. For many, the emergency department may be the only source of medical care or interaction with a health care provider. This makes the emergency department an ideal place to identify individuals with elevated random blood glucose levels, inform them of the elevation, and refer them for follow-up.

METHODS

This was a descriptive, correlational, cross-sectional study using retrospective data from 2 emergency departments in north San Diego County to determine the incidence of elevated blood glucose levels and the disposition of these individuals. Descriptive and correlational statistical analyses were completed with SPSS software (IBM, Armonk, NY).

RESULTS

Patients (N = 106) with random blood glucose levels of 150 mg/dL or greater, without a prior diagnosis of diabetes, were identified over a 9-day period. The mean glucose level was 181.53 mg/dL. Of the patients, 45 (42%) were discharged. Only 1 of these 45 patients (2.2%) was informed about the elevated blood glucose level and referred for follow-up.

DISCUSSION

Emergency nurses and providers care for patients with elevated blood glucose levels who may have undiagnosed prediabetes. The finding that only 1 patient with an elevated glucose level was informed and referred for follow-up indicates opportunities to address this population of patients who are being missed. Failing to inform and provide referral minimizes patients' abilities to make relevant lifestyle changes to help prevent or delay progression to type 2 diabetes.

Prediabetes: the importance of early identification and intervention

Prediabetes is a state of abnormal glucose homeostasis characterized by the presence of impaired fasting glucose, impaired glucose tolerance, or both. Individuals with prediabetes are at increased risk for type 2 diabetes, compared with individuals with normal glucose values (normal fasting plasma glucose, < 100 mg/dL [5.6 mmol/L]). The increased risk for cardiovascular disease in prediabetes is multifactorial, with etiologies including insulin resistance, hyperglycemia, dyslipidemia, hypertension, systemic inflammation, and oxidative stress. The preferred treatment is intensive lifestyle management and aggressive pharmacologic therapies directed toward individual coronary heart disease risk factors. The use of antihyperglycemic agents in this setting is a topic of intense debate. This review discusses the pathophysiology of prediabetes and its clinical implications, highlighting the importance of early identification and intervention.

Rationale and design of a clinical trial to evaluate metformin and colesevelam HCl as first-line therapy in type 2 diabetes and colesevelam HCl in prediabetes

OBJECTIVE

The complications of type 2 diabetes mellitus (DM) can begin early in the progression from impaired glucose tolerance to type 2 DM. Metformin is recommended as initial drug therapy for managing hyperglycemia in type 2 DM. The bile acid sequestrant colesevelam hydrochloride (HCl) is approved in the United States for glycemic control in adults with type 2 DM. Colesevelam HCl improves glycemic control and reduces low-density lipoprotein-cholesterol in patients inadequately controlled on metformin-, sulfonylurea-, or insulin-based therapy. This trial is designed to evaluate whether initial therapy with metformin + colesevelam HCl provides greater glucose control and additional lipid and lipoprotein benefits, as compared to metformin alone in drug-naïve patients with type 2 DM, and whether treatment with colesevelam HCl has a beneficial effect on lipid and glucose levels in drug-naïve patients with impaired glucose tolerance and/or impaired fasting glucose (prediabetes).

RESEARCH DESIGN AND METHODS

In this multicenter, randomized, double-blind, placebo-controlled, parallel-group trial, drug-naïve patients with type 2 DM will be randomized 1 : 1 to metformin + colesevelam HCl or metformin + matching placebo, while those with prediabetes will be randomized 1 : 1 to colesevelam HCl or placebo, for 16 weeks of treatment. The primary efficacy endpoint will be change in glycosylated hemoglobin (HbA(1c)) in patients with type 2 DM and change in low-density lipoprotein-cholesterol levels in patients with prediabetes.

CONCLUSION

A potential limitation is that there is no direct comparator for the dual glucose- and lipid-lowering effect of colesevelam HCl in the prediabetes cohort. However, results of this trial will help to define the extent to which colesevelam HCl can help improve cardiometabolic risk factors for complications of type 2 DM in the first-line environment, and will also indicate the extent to which early intervention with colesevelam HCl can help to correct metabolic abnormalities associated with prediabetes.