Adiponectin levels predict prediabetes risk: the Pathobiology of Prediabetes in A Biracial Cohort (POP-ABC) study

Exogenous APN protects normal tissues from radiation-induced oxidative damage and fibrosis in mice and prostate cancer patients with higher levels of APN have less radiation-induced toxicities

Radiation causes damage to normal tissues that leads to increased oxidative stress, inflammation, and fibrosis, highlighting the need for the selective radioprotection of healthy tissues without hindering radiotherapy effectiveness in cancer. This study shows that adiponectin, an adipokine secreted by adipocytes, protects normal tissues from radiation damage invitro and invivo. Specifically, adiponectin (APN) reduces chronic oxidative stress and fibrosis in irradiated mice. Importantly, APN also conferred no protection from radiation to prostate cancer cells. Adipose tissue is the primary source of circulating endogenous adiponectin. However, this study shows that adipose tissue is sensitive to radiation exposure exhibiting morphological changes and persistent oxidative damage. In addition, radiation results in a significant and chronic reduction in blood APN levels from adipose tissue in mice and human prostate cancer patients exposed to pelvic irradiation. APN levels negatively correlated with bowel toxicity and overall toxicities associated with radiotherapy in prostate cancer patients. Thus, protecting, or modulating APN signaling may improve outcomes for prostate cancer patients undergoing radiotherapy.

Ethnic Disparities in the Risk Factors, Morbidity, and Mortality of Cardiovascular Disease in People With Diabetes

Cardiovascular disease (CVD) is the leading cause of death in people with diabetes. Compared with European Americans, African Americans have more favorable lipid profiles, as indicated by higher high-density lipoprotein cholesterol, lower triglycerides, and less dense low-density lipoprotein particles. The less atherogenic lipid profile translates to lower incidence and prevalence of CVD in African Americans with diabetes, despite higher rates of hypertension and obesity. However, African Americans with CVD experience worse clinical outcomes, including higher mortality, compared with European Americans. This mini-review summarizes the epidemiology, pathophysiology, mechanisms, and management of CVD in people with diabetes, focusing on possible factors underlying the "African American CVD paradox" (lower CVD incidence/prevalence but worse outcomes). Although the reasons for the disparities in CVD outcomes remain to be fully elucidated, we present a critical appraisal of the roles of suboptimal control of risk factors, inequities in care delivery, several biological factors, and psychosocial stress. We identify gaps in current knowledge and propose areas for future investigation.

Serum adiponectin and peroxisome proliferator-activated receptors-γ levels in obese patients with and without prediabetes

OBJECTIVE

Obesity is an increasingly prevalent global health problem, which is generally caused by the increase in body fat mass above normal and observed in all societies. If the blood glucose level is higher than normal but not high enough to diagnose diabetes, this condition is defined as prediabetes. Adiponectin increases fatty acid oxidation and insulin sensitivity and is closely associated with obesity. One of the nuclear receptor superfamily member peroxisome proliferator-activated receptors is shown to have an important role in various metabolic reactions. This study aimed to investigate the serum levels of adiponectin and peroxisome proliferator-activated receptors-gamma parameters, which are closely related to adipose tissue, energy metabolism, and insulin sensitivity, in obese patients with and without prediabetes.

METHODS

For this purpose, 52 obese patients with prediabetes, 48 obese patients with non-prediabetes, and 76 healthy individuals were included in this study. Serum adiponectin and peroxisome proliferator-activated receptors-γ levels were analyzed by ELISA.

RESULTS

Serum adiponectin levels were significantly higher in obese patients with prediabetes (18.15±15.99) compared with the control group (15.17±15.67; p=0.42). No significant difference was observed in both adiponectin and peroxisome proliferator-activated receptors-γ levels in the obese patients with the non-prediabetes group compared with the control group. However, no significant difference was observed in the obese patients with prediabetes group and obese patients with non-prediabetes group.

CONCLUSION

Our results suggest that adiponectin may serve as an indicator of prediabetes. This implies that examining adiponectin levels in individuals diagnosed with prediabetes may enhance our understanding of the metabolic processes closely linked to prediabetes and related conditions.

Plasma Ceramides and Other Sphingolipids in Relation to Incident Prediabetes in a Longitudinal Biracial Cohort

CONTEXT

Sphingolipids are linked to the pathogenesis of type 2 diabetes (T2D).

OBJECTIVE

To test the hypothesis that plasma sphingolipid profiles predict incident prediabetes.

DESIGN

A case-control study nested in the Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) study, a 5-year follow-up study.

SETTING

Academic health center.

PARTICIPANTS

Normoglycemic adults enrolled in the POP-ABC study. Assessments included OGTT, insulin sensitivity and insulin secretion. Participants with incident prediabetes were matched in age, sex, and ethnicity with non-progressors.

INTERVENTIONS

We assayed 58 sphingolipid species (ceramides, monohexosyl ceramides, sphingomyelins, and sphingosine) using LC/tandem mass spectrometry in baseline plasma levels from participants and determined association with prediabetes risk.

MAIN OUTCOME MEASURE

The primary outcome was progression from normoglycemia to prediabetes, defined as impaired fasting glucose or impaired glucose tolerance.

RESULTS

The mean age of participants (N = 140; 50% Black, 50% female) was 48.1 ± 8.69 y, BMI 30.1 ± 5.78 kg/m2, fasting plasma glucose (FPG) 92.7 ± 5.84 mg/dl, and two-hour plasma glucose (2hrPG) 121 ± 23.3 mg/dl. Of the 58 sphingolipid species assayed, higher ratios of sphingomyelin C26:0/C26:1 (OR 2.73 [95% CI 1.172-4.408], P = 0.015) and ceramide C18:0/C18:1 (OR 1.236 [95% CI 1.042-1.466], P = 0.015) in baseline plasma specimens were significantly associated with progression to prediabetes during the 5-year follow-up period, after adjustments for age, race, sex, BMI, FPG, 2hPG, insulin sensitivity, and insulin secretion.

CONCLUSIONS

We conclude that the saturated-to-monounsaturated ratios of long-chain ceramide C18:0/C18:1 and very-long-chain sphingomyelin C26:0/C26:1 are potential biomarkers of prediabetes risk among individuals with parental history of T2D.

Liquid Biopsy: A Game Changer for Type 2 Diabetes

As the burden of type 2 diabetes (T2D) continues to escalate globally, there is a growing need for novel, less-invasive biomarkers capable of early diabetes detection and monitoring of disease progression. Liquid biopsy, recognized for its minimally invasive nature, is increasingly being applied beyond oncology, and nevertheless shows its potential when the collection of the tissue biopsy is not possible. This diagnostic approach involves utilizing liquid biopsy markers such as cell-free nucleic acids, extracellular vesicles, and diverse metabolites for the molecular diagnosis of T2D and its related complications. In this context, we thoroughly examine recent developments in T2D liquid biopsy research. Additionally, we discuss the primary challenges and future prospects of employing liquid biopsy in the management of T2D. Prognosis, diagnosis and monitoring of T2D through liquid biopsy could be a game-changing technique for personalized diabetes management.

Therapeutic potential of adiponectin in prediabetes: strategies, challenges, and future directions

Adiponectin, an adipose-derived hormone, plays a pivotal role in glucose regulation and lipid metabolism, with a decrease in circulating adiponectin levels being linked to insulin resistance and prediabetes. This review examines the therapeutic potential of adiponectin in managing prediabetes, elucidating on multiple aspects including its role in glucose and lipid metabolism, influence on insulin sensitivity, and anti-inflammatory properties. Moreover, the paper highlights the latest strategies to augment adiponectin levels, such as gene therapy, pharmacological interventions, dietary modifications, and lifestyle changes. It also addresses the challenges encountered in translating preclinical findings into clinical practice, primarily related to drug delivery, safety, and efficacy. Lastly, the review proposes future directions, underlining the need for large-scale human trials, novel adiponectin analogs, and personalized treatment strategies to harness adiponectin's full therapeutic potential in preventing the transition from prediabetes to diabetes.

Glycemic and metabolic sub-classification of prediabetes and risk factors for cardiovascular disease in the D2d cohort

Objectives

Prediabetes represents a spectrum of metabolic abnormalities, including insulin resistance and secretory impairment, that carries increased cardiovascular disease (CVD) risk. It is unclear whether specific glycemic and metabolic sub-classifications are associated with CVD risk. This cross-sectional analysis of 3946 participants from the Vitamin D and Type 2 Diabetes (D2d) study cohort aimed to determine the associations between various baseline CVD risk factors, glycemic sub-classifications of prediabetes (FPG, 2hPG, and HbA1c), and measures of insulin sensitivity and secretion from an OGTT.

Methods

The metabolic syndrome and atherosclerotic cardiovascular disease (ASCVD) risk scores were determined for tertiles of insulin sensitivity (HOMA2S) and insulinogenic index (IGI). Unadjusted analyses showed elevated CVD risk factors in the lowest tertile for both IGI and HOMA2S.

Results

After adjustment for age, gender, race, obesity, and smoking status, the association remained between HOMA2S and ASCVD score (r = -0.11, p< 0.001) but not for IGI. Those who met at least 2 diagnosic criteria for prediabetes had the largest proportion (> 40%) of participants with high ASCVD risk score >20. A higher percentage of individuals that met all 3 criteria for prediabetes had metabolic syndrome and ASCVD risk score >20 (87.2% and 15.3%, respectively) than those who only met 1 prediabetes criterion (51.6% and 7.1%, respectively).

Conclusions

In conclusion, multiple metabolic (HOMA2S, IGI) and glycemic criteria of prediabetes (FPG, 2hPG, & HbA1c) are needed to fully recognize the elevated CVD risk profile that can manifest in prediabetes.

Evaluation of Adiponectin and ANGPTL8 in Women With Metabolic Syndrome in the Madinah Region of Saudi Arabia

OBJECTIVE

 "Metabolic syndrome" (MetS) is a set of abnormalities that may be risk factors for cardiovascular disease (CVD) and diabetes. The current study sought to (1) determine MetS prevalence and (2) examine Adiponectin and ANGPTL8 levels in connection to MetS components and CVDs and diabetes risk in females with MetS.

METHODS

A total of 350, 20-35-year-old Saudi females were studied. Waist circumference (WC), body mass index (BMI), glucose, HbA1c, insulin, lipid profiles, and blood pressure (BP) were examined for MetS. ANGPTL8 and Adiponectin were also measured.

RESULTS

The patients were classified into two groups, namely MetS and non-MetS, according to the criteria established by the National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATPIII). We examined biomarker and anthropometric results between these groups. One hundred forty-four of 350 female participants (41.2%) had MetS, with a mean age of 30.5 years. Fasting blood glucose (FBG), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), ANGPTL8, adiponectin, and insulin resistance (IR) were statistically significant differences observed between the two groups. BP, BMI, WC, and Atherogenic Index of Plasma (AIP) all changed significantly (P ≤0.05). Correlation studies linked MetS components to higher ANGPTL-8 and reduced adiponectin. The levels of ANGPTL8 were shown to be influenced by the increase in FBG, TG, BP, IR, and AIP (P < 0.05). Factors such as FBG, BMI, WC, and IR have been found to have an inverse relationship with adiponectin levels.

CONCLUSION

41.2% out of 350 Saudi females at Taibah University in the Madinah region had MetS, medium CVD risk, and slightly elevated BMI, TG, WC, and BP. To lower their risk of CVD and diabetes later in life, overweight young women should be evaluated for MetS. FBG and TG were substantially associated with ANGPTL8 while reducing adiponectin was associated with elevated TG and BP. Our findings may lead to ANGPTL8 and adiponectin's possible predictive function for CVD in early MetS in females.

Adiponectin as a therapeutic target for diabetic foot ulcer

The global burden of diabetic foot ulcers (DFUs) is a significant public health concern, affecting millions of people worldwide. These wounds cause considerable suffering and have a high economic cost. Therefore, there is a need for effective strategies to prevent and treat DFUs. One promising therapeutic approach is the use of adiponectin, a hormone primarily produced and secreted by adipose tissue. Adiponectin has demonstrated anti-inflammatory and anti-atherogenic properties, and researchers have suggested its potential therapeutic applications in the treatment of DFUs. Studies have indicated that adiponectin can inhibit the production of pro-inflammatory cytokines, increase the production of vascular endothelial growth factor, a key mediator of angiogenesis, and inhibit the activation of the intrinsic apoptotic pathway. Additionally, adiponectin has been found to possess antioxidant properties and impact glucose metabolism, the immune system, extracellular matrix remodeling, and nerve function. The objective of this review is to summarize the current state of research on the potential role of adiponectin in the treatment of DFUs and to identify areas where further research is needed in order to fully understand the effects of adiponectin on DFUs and to establish its safety and efficacy as a treatment for DFUs in the clinical setting. This will provide a deeper understanding of the underlying mechanisms of DFUs that can aid in the development of new and more effective treatment strategies.

Association of bone mineral density with prediabetes risk among African-American and European-American adult offspring of parents with type 2 diabetes

Introduction

Type 2 diabetes mellitus (T2DM) is associated with alterations in bone mineral density (BMD), but association between prediabetes and BMD is unclear.

Methods

We analyzed BMD among the initially normoglycemic participants in the Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) study in relation to incident prediabetes during 5 years of follow-up.

Results and Discussion

A total of 343 participants (193 Black, 150 White) underwent DEXA during Year 1 of POP-ABC and were followed quarterly for 5 years. The mean age was 44.2 ± 10.6 years; BMI was 30.2 ± 7.23 kg/m2. At baseline, the mean BMD was 1.176 ± 0.135 g/cm2 (1.230 ± 0.124 g/cm2 in men vs. 1.154 ± 0.134 g/cm2 in women, P<0.0001; 1.203 ± 0.114 g/cm2 in Black vs. 1.146 ± 0.150 g/cm2 in White participants, P=0.0003). During 5 years of follow-up, 101 participants developed prediabetes and 10 subjects developed T2DM (progressors); 232 were nonprogressors. Progressors to prediabetes had numerically higher baseline BMD and experienced lower 1-year decline in BMD (P<0.0001) compared with nonprogressors. From Kaplan-Meier analysis, the time to 50% prediabetes survival was 2.15 y among participants in the lowest quartile of baseline BMD, longer than those in higher quartiles (1.31 - 1.41 y). Values for BMD correlated inversely with age and adiponectin levels, and positively with BMI. In logistic regression analysis, BMD z score significantly predicted incident prediabetes: more negative BMD z scores were associated with decreased incident prediabetes (odds ratio 0.598 [95% confidence interval 0.407 - 0.877], P=0.0085), after controlling for age, BMI, change in BMI, ethnicity, blood glucose and adiponectin.

Conclusions

Among initially normoglycemic individuals, higher baseline BMD was associated with higher risk of incident prediabetes during 5 years of follow-up.

Circulating and Adipose Tissue Adiponectin Level and Outcomes in Incident Peritoneal Dialysis Patients

Rationale & Objective

Cardiovascular disease is the major cause of mortality and morbidity in peritoneal dialysis (PD) patients. Adiponectin, a key adipokine, is related to obesity and insulin resistance. We determined the clinical and prognostic value of plasma adiponectin level and its adipose tissue messenger RNA (mRNA) expression in new PD patients.

Study Design

Retrospective analysis of a prospective observational study.

Setting & Participants

152 new PD patients from a single center; 6 adults undergoing abdominal surgeries without kidney disease served as controls.

Predictors

Plasma adiponectin level and its adipose tissue mRNA expression.

Outcomes

Body build and composition, patient and technique survival.

Analytical Approach

Adiponectin level and mRNA expression were grouped in quartiles for correlation analysis for body build and Cox regression for survival analysis.

Results

The median plasma adiponectin level was 31.98 μg/mL (IQR, 16.81-49.49 μg/mL), and adiponectin mRNA expression in adipose tissue was 1.65 times higher than in controls (IQR, 0.98-2.63). There was a modest but statistically significant correlation between plasma adiponectin and its adipose tissue mRNA expression (r = 0.40, P < 0.001). Plasma adiponectin level inversely correlated with body mass index, waist-hip ratio, mid-arm circumference, adipose tissue mass, plasma triglyceride (r = -0.39, -0.38, -0.41, -0.38, and -0.30, respectively; P < 0.001 for all), as well as serum insulin level (r = -0.24, P = 0.005). Similar correlations were present but less marked with adipose tissue adiponectin mRNA level. Neither plasma adiponectin level nor adipose tissue adiponectin mRNA level predicted patient or technique survival.

Limitations

Observational study, single center, single baseline measurement.

Conclusions

Plasma adiponectin level correlated with the degree of adiposity in new PD patients. However, neither plasma adiponectin level nor its adipose tissue mRNA expression was an independent prognostic indicator in kidney failure patients newly started on PD.

Poor Eating Behaviors Related to the Progression of Prediabetes in a Japanese Population: An Open Cohort Study

This study aimed to examine lifestyle factors associated with the change in glucose categories among individuals without diabetes. We analyzed cohort data of medical check-ups at baseline between April 2008 and December 2012. The primary and secondary outcomes were the change in glucose categories from normoglycemia (glycated hemoglobin (HbA1c) < 5.7% and fasting plasma glucose (FPG) < 5.6 mmol/L) to prediabetes (HbA1c 5.7-6.4% or FPG 5.6-6.9 mmol/L) and from prediabetes to normoglycemia. During a mean follow-up of 2.4 years, 7083 of 57,018 individuals with normoglycemia developed prediabetes, whereas 4629 of 9926 individuals with prediabetes returned to normoglycemia. Factors associated with progression to prediabetes were baseline BMI (hazard ratio [95% confidence interval]: 1.08 [1.07-1.09]), change in BMI during follow-up (1.05 [1.03-1.07]), late dinner/snacking (1.16 [1.10-1.22]), skipping breakfast (1.12 [1.06-1.18]), and heavy alcohol consumption (1.33 [1.24-1.42]). Factors associated with return to normoglycemia from prediabetes were baseline BMI (0.94 [0.93-0.95]) and change in BMI during follow-up (0.95 [0.93-0.97]). In conclusion, poor eating behaviors, such as skipping breakfast, late dinner/snacking, and heavy alcohol consumption, were associated with the progression from normoglycemia to prediabetes.

Adiponectin Can Be an Early Predictable Marker for Type 2 Diabetes Mellitus and Nephropathy

Background

Several studies have examined serum adiponectin concentrations in prediabetes, newly diagnosed type 2 diabetes mellitus (T2DM), and other types of diabetes associated with the risk of T2DM and diabetic nephropathy (DN); however, the results to date are inconclusive. An aim of the current study is to determine whether adiponectin is a useful marker for the earlier development of T2DM and DN.

Methodology

This cross-sectional study included 400 subjects. Among the subjects, 100 were prediabetes subjects, 200 were T2DM patients, and the remaining 100 were healthy controls. The biochemical and clinical parameters of all patients were analyzed and the data were recorded.

Results

The mean levels of adiponectin were significantly lower in prediabetic subjects than in healthy controls (3.22 ± 0.98, 5.36 ± 2.24, p = 0.0001**). Furthermore, the levels of adiponectin were significantly higher in both the groups of T2DM patients when compared to healthy controls (19.85 ± 3.31, 11.83 ± 3.01, and 5.36 ± 2.24, p = 0.0001**). In both diabetic groups, adiponectin was positively correlated with body mass index, glycated hemoglobin, insulin, homeostasis model assessment of insulin resistance, and microalbuminuria, while negatively correlated with estimated glomerular filtration rate. Interestingly, adiponectin had a reversed correlation in the prediabetic group.

Conclusion

Based on the results, the present study suggests that significantly decreased levels of serum adiponectin in prediabetic subjects might be used as a variable marker for T2DM. Moreover, adiponectin may useful for detecting the early onset of nephropathy, compared to microalbumin, as its concentration was significantly elevated in patients who were newly diagnosed with T2DM without nephropathy. 

Longitudinal association of inflammatory markers with markers of glycaemia and insulin resistance in European children

PURPOSE

Subclinical systemic inflammation may lead to development of type 2 diabetes, but there has been no investigation into its relationship with early progression of glycaemic deterioration and insulin resistance, especially in younger population. In this study we assessed longitudinal associations of pro- and anti-inflammatory markers with markers that evaluate glycaemia and insulin resistance.

METHODS

This study includes 6537 initially nondiabetic children (mean age at baseline = 6.2 years) with repeated measurements from the IDEFICS/I.Family cohort study (mean follow-up = 5.3 years) from eight European countries. Markers of inflammation were used as independent variables and markers of glycaemia/insulin resistance as dependent variables. Associations were examined using two-level growth model. Models were adjusted for sex, age, major lifestyle, metabolic risk factors, early life markers, and other inflammatory markers in final model.

RESULTS

Children with 6 years of follow-up showed that a one-unit increase in z-score of leptin level was associated with 0.38 (95% CI = 0.32 to 0.44) unit increase in HOMA-IR z-scores. Leptin continued to be associated with HOMA-IR even when analysis was limited to children with no overall obesity, no abdominal obesity, and low to normal triglyceride levels. An inverse association was observed between IL-15 and HOMA-IR (β = -0.11, 95% CI = -0.15 to -0.07).

CONCLUSIONS

IL-15 should be evaluated further in the prevention or treatment of prediabetes whereas leptin may prove to be useful in early detection of prediabetes via their association with markers of insulin resistance in European children.

Outcome of lifestyle intervention in relation to duration of pre-diabetes: the Pathobiology and Reversibility of Prediabetes in a Biracial Cohort (PROP-ABC) study

INTRODUCTION

In studies that enrolled people with prevalent pre-diabetes of unknown duration, lifestyle intervention (LI) delayed progression to type 2 diabetes (T2D) but did not reverse pre-diabetes in most participants. Here, we assessed the effects of LI among individuals with pre-diabetes of known duration to determine whether outcomes are related to duration of pre-diabetes.

RESEARCH DESIGN AND METHODS

The Pathobiology and Reversibility of Prediabetes in a Biracial Cohort study initiated LI in subjects with incident pre-diabetes during follow-up of initially normoglycemic African Americans and European Americans with parental T2D. Participants were stratified into those initiating LI after <3, 3-5, or >5 years of pre-diabetes diagnosis. Assessments included anthropometry, body fat, fasting and 2-hour plasma glucose (FPG, 2hPG), and insulin sensitivity and secretion. The outcomes were normal glucose regulation (NGR; ie, normal FPG and 2hPG), persistent pre-diabetes, or T2D. Participants who maintained normal FPG and normal 2hPG levels during follow-up served as the control. The control subjects did not receive lifestyle or other intervention to alter the course of glycemia or body weight.

RESULTS

Of 223 participants (age 53.3±9.28 years, body mass index 30.6±6.70 kg/m²), 72 (control) maintained normoglycemia during follow-up and 138 subjects with incident pre-diabetes initiated LI after 4.08±2.02 years (range 3 months-8.3 years) of diagnosis. Compared with control, LI participants showed decrease in glucose, weight, and body fat; 42.8% reverted to NGR, 50% had persistent pre-diabetes, and 7.2% developed T2D after 5 years. These outcomes were similar across race and pre-diabetes duration strata, but greater glycemic decrease occurred when LI was initiated within 5 years of pre-diabetes diagnosis.

CONCLUSIONS

Ninety-three per cent of adults with parental T2D who initiated LI within 3 months to 8.3 years of developing pre-diabetes did not progress to T2D; nearly half reverted to NGR.Trial registration number NCT02027571.

The association of adiponectin with risk of pre-diabetes and diabetes in different subgroups: cluster analysis of a general population in south China

OBJECTIVE

Adiponectin is an adipocyte-derived hormone with an important role in glucose metabolism. The present study explored the effect of adiponectin in diverse population groups on pre-diabetes and newly diagnosed diabetes.

METHODS

A total of 3300 individuals were enrolled and their data were collected in the analyses dataset from December 2018 to October 2019. Cluster analysis was conducted based on age, BMI, waistline, body fat, systolic blood pressure, triglycerides, and glycosylated hemoglobin 1c. Cluster analysis divided the participants into four groups: a young-healthy group, an elderly-hypertension group, a high glucose-lipid group, and an obese group. Odds ratio (OR) and 95% CIs were calculated using multivariate logistic regression analysis.

RESULTS

Compared with the first quartile of adiponectin, the risk of pre-diabetes of fourth quartile was decreased 61% (aOR = 0.39, 95% CI (0.20-0.73)) in the young-healthy group; and the risk of diabetes of fourth quartile was decreased 85% (aOR = 0.15, 95% CI (0.02-0.67)) in the obese group. There were no significant correlations between the adiponectin level and diabetes/pre-diabetes in the other two groups. Additionally, receiver operating characteristic curve analysis indicated that adiponectin could significantly improve the diagnosis based on models in the young-healthy group (from 0.640 to 0.675) and the obese group (from 0.714 to 0.761).

CONCLUSIONS

Increased adiponectin levels were associated with decreased risk of pre-diabetes in the young-healthy population, and with a decreased the risk of diabetes in the obese population. An increased adiponectin level is an independent protective factor for pre-diabetes and diabetes in a specific population in south China.

Metabolic Dysfunction Biomarkers as Predictors of Early Diabetes

During the pathophysiological course of type 2 diabetes (T2D), several metabolic imbalances occur. There is increasing evidence that metabolic dysfunction far precedes clinical manifestations. Thus, knowing and understanding metabolic imbalances is crucial to unraveling new strategies and molecules (biomarkers) for the early-stage prediction of the disease's non-clinical phase. Lifestyle interventions must be made with considerable involvement of clinicians, and it should be considered that not all patients will respond in the same manner. Individuals with a high risk of diabetic progression will present compensatory metabolic mechanisms, translated into metabolic biomarkers that will therefore show potential predictive value to differentiate between progressors/non-progressors in T2D. Specific novel biomarkers are being proposed to entrap prediabetes and target progressors to achieve better outcomes. This study provides a review of the latest relevant biomarkers in prediabetes. A search for articles published between 2011 and 2021 was conducted; duplicates were removed, and inclusion criteria were applied. From the 29 studies considered, a survey of the most cited (relevant) biomarkers was conducted and further discussed in the two main identified fields: metabolomics, and miRNA studies.

Can vitamin D be considered an adiponectin secretagogue? A systematic review and meta-analysis

There is some evidence for ameliorating effect of vitamin D on glycemic and lipidemic status which are likely to be mediated through other molecules including adiponectin. However, the overall results have been controversial. This study was conducted to evaluate the effect of vitamin D supplementation on serum adiponectin concentration. MEDLINE, PubMed, Embase, Cochrane Library, and Google Scholar were searched and 402 studies were found in a preliminary search. After screening of titles and abstracts nine studies were selected. Pooled data showed no significant effect on adiponectin concentrations (mean difference (MD) 0.37, 95 % CI: -0.1 to 0.87). However, there was a significant effect in a subgroup of participants who had diabetes (MD: 0.03, 95 % CI: 0.00 to 0.05, p = 0.029). The treatment effect on adiponectin concentrations was significant in those trials that used supplementation on a daily basis (MD: 0.03, 95 % CI: 0.00 to 0.05, p = 0.028) and vitamin D plus calcium (MD: 0.04, 95 % CI: 0.01 to 0.07, p = 0.014). The meta-regression revealed a significant association between BMI and age of participants at baseline and the treatment effect (B, -0.144, 95 % CI: -0.276 to -0.011, p = 0.033 and B, -0.043, 95 % CI: -0.075 to -0.012, p = 0.006). The results of this meta-analysis study indicates that vitamin D may be considered an adiponectin secretagogue in subjects with diabetes and this effect may be potentiated if vitamin D intake is on daily basis and in combination with calcium but can be weakened by increasing BMI.

FGF21/adiponectin ratio predicts deterioration in glycemia: a 4.6-year prospective study in China

Background

The fibroblast growth factor (FGF) 21-adiponectin pathway is involved in the regulation of insulin resistance. However, the relationship between the FGF21-adiponectin pathway and type 2 diabetes in humans is unclear. Here, we investigated the association of FGF21/adiponectin ratio with deterioration in glycemia in a prospective cohort study.

Methods

We studied 6361 subjects recruited from the prospective Shanghai Nicheng Cohort Study in China. The association between baseline FGF21/adiponectin ratio and new-onset diabetes and incident prediabetes was evaluated using multiple logistic regression analysis.

Results

At baseline, FGF21/adiponectin ratio levels increased progressively with the deterioration in glycemic control from normal glucose tolerance to prediabetes and diabetes (p for trend < 0.001). Over a median follow-up of 4.6 years, 195 subjects developed new-onset diabetes and 351 subjects developed incident prediabetes. Elevated baseline FGF21/adiponectin ratio was a significant predictor of new-onset diabetes independent of traditional risk factors, especially in subjects with prediabetes (odds ratio, 1.367; p = 0.001). Moreover, FGF21/adiponectin ratio predicted incident prediabetes (odds ratio, 1.185; p = 0.021) while neither FGF21 nor adiponectin were independent predictors of incident prediabetes (both p > 0.05). Furthermore, net reclassification improvement and integrated discrimination improvement analyses showed that FGF21/adiponectin ratio provided a better performance in diabetes risk prediction than the use of FGF21 or adiponectin alone.

Conclusions

FGF21/adiponectin ratio independently predicted the onset of prediabetes and diabetes, with the potential to be a useful biomarker of deterioration in glycemia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01351-1.

Glucose Effectiveness Decreases in Relationship to a Subtle Worsening of Metabolic Parameters in Young Japanese with Normal Glucose Tolerance

Background: The aim of the study was to investigate the relationship between glucose effectiveness (Sg) and some metabolic parameters in male and female young Japanese. Methods: We measured plasma glucose and immunoreactive insulin levels in 1309 young Japanese persons (age <40 years) with normal glucose tolerance (NGT) before and at 30, 60, and 120 min during a 75 gram oral glucose tolerance test. We also measured serum adiponectin and high-sensitivity C-reactive protein (hsCRP) levels and oral glucose effectiveness (SgI_O), and investigated factors related to SgI_O. Results: The results of Spearman correlation analysis revealed that high-density lipoprotein cholesterol (HDL) and adiponectin were positively correlated with SgI_O, whereas the proportion of males, body mass index, waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure, triglycerides (TG), and hsCRP were inversely correlated with SgI_O. The results of multiple regression analysis indicated negative correlations between SgI_O and the proportion of males, WC, and SBP and a positive correlation with HDL. The results of multiple regression analysis excluding WC indicated negative correlations between SgI_O and the proportion of males, SBP, and TG and positive correlations with HDL and adiponectin. Conclusions: Sg decreased with a subtle worsening of metabolic parameters, even in young persons with NGT. Decreased Sg may be involved in the development of glucose intolerance in individuals with worse metabolic parameters.

Emerging Diabetic Novel Biomarkers of the 21st Century

Diabetes is a growing epidemic with estimated prevalence of infected to reach ~592 million by the year 2035. An effective way to approach is to detect the disease at a very early stage to reduce the complications and improve lifestyle management. Although several traditional biomarkers including glucated hemoglobin, glucated albumin, fructosamine, and 1,5-anhydroglucitol have helped in ease of diagnosis, there is lack of sensitivity and specificity and are inaccurate in certain clinical settings. Thus, search for new and effective biomarkers is a continuous process with an aim of accurate and timely diagnosis. Several novel biomarkers have surged in the present century that are helpful in timely detection of the disease condition. Although it is accepted that a single biomarker will have its inherent limitations, combining several markers will help to identify individuals at high risk of developing prediabetes and eventually its progression to frank diabetes. This review describes the novel biomarkers of the 21st century, both in type 1 and type 2 diabetes mellitus, and their present potential for assessing risk stratification due to insulin resistance that will pave the way for improved clinical outcome.

Association of plasma acylcarnitines with insulin sensitivity, insulin secretion, and prediabetes in a biracial cohort

The ability to predict prediabetes, which affects ∼90 million adults in the US and ∼400 million adults worldwide, would be valuable to public health. Acylcarnitines, fatty acid metabolites, have been associated with type 2 diabetes risk in cross-sectional studies of mostly Caucasian subjects, but prospective studies on their link to prediabetes in diverse populations are lacking. Here, we determined the association of plasma acylcarnitines with incident prediabetes in African Americans and European Americans enrolled in a prospective study. We analyzed 45 acylcarnitines in baseline plasma samples from 70 adults (35 African-American, 35 European-American) with incident prediabetes (progressors) and 70 matched controls (non-progressors) during 5.5-year (mean 2.6 years) follow-up in the Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) study. Incident prediabetes (impaired fasting glucose/impaired glucose tolerance) was confirmed with OGTT. We measured acylcarnitines using tandem mass spectrometry, insulin sensitivity by hyperinsulinemic euglycemic clamp, and insulin secretion using intravenous glucose tolerance test. The results showed that progressors and non-progressors during POP-ABC study follow-up were concordant for 36 acylcarnitines and discordant for nine others. In logistic regression models, beta-hydroxy butyryl carnitine (C4-OH), 3-hydroxy-isovaleryl carnitine/malonyl carnitine (C5-OH/C3-DC), and octenoyl carnitine (C8:1) were the only significant predictors of incident prediabetes. The combined cut-off plasma levels of <0.03 micromol/L for C4-OH, <0.03 micromol/L for C5-OH/C3-DC, and >0.25 micromol/L for C8:1 acylcarnitines predicted incident prediabetes with 81.9% sensitivity and 65.2% specificity. Thus, circulating levels of one medium-chain and two short-chain acylcarnitines may be sensitive biomarkers for the risk of incident prediabetes among initially normoglycemic individuals with parental history of type 2 diabetes.

Effect of physical activity promotion on adiponectin, leptin and other inflammatory markers in prediabetes: a systematic review and meta-analysis of randomized controlled trials

AIMS

Inflammatory stage in prediabetes is associated with increase in level of adipokines and pro-inflammatory cytokines. Physical activity promotion considered as a first-line therapeutic strategy to treat prediabetes. We have conducted the systematic review and meta-analysis to strengthen the evidence on the impact of physical activity promotion on inflammatory markers in prediabetes.

METHODS

Studies were identified using electronic search and manual search techniques by choosing keywords for prediabetes, physical activity and inflammatory marker. Randomized controlled trials on individuals diagnosed with prediabetes and provided intervention in the form of physical activity were included in this review. Adiponectin, leptin, C-reactive protein, interleukin-6 and tumour necrosis factor-α were the considered outcome measures.

RESULTS

Our search retrieved 1,688 citations, 31 full-text articles assessed for eligibility of inclusion. Nine studies satisfied the pre-specified criteria for inclusion. Meta-analysis found that physical activity with or without dietary or lifestyle modification reduces level of leptin (MD-2.11 ng/mL, 95% CI -3.81 - -0.42) and interleukin-6 (MD -0.15 pg/mL, 95% CI -0.25--0.04). It has no effect on level of adiponectin (MD 0.26 µg/mL, 95% CI -0.42- 0.93), C-reactive protein (MD -0.05 mg/L, 95% CI -0.33-0.23) and tumour necrosis factor-α (MD 0.67 pg/mL, 95% CI -2.56-3.89).

CONCLUSIONS

This review suggests that physical activity promotion with dietary and lifestyle modification may reduce the level of leptin and interleukin-6 but are uncertain if there is any effect on levels of adiponectin, C-reactive protein and tumour necrosis factor-α in the individuals with prediabetes.

Dietary quality score is positively associated with serum adiponectin level in Indonesian preschool-age children living in the urban area of Jakarta

An unhealthy diet during childhood directly impacts the risk of developing noncommunicable diseases (NCDs) later on in life. However, well-documented information on this issue is lacking. We investigated the dietary quality of young Indonesian children and assessed the relationship to serum adiponectin levels as an early marker of NCDs. Eighty-five (44 girls and 41 boys) Indonesian preschool-age children in East Jakarta were included in this study. Dietary intake data were gathered by collecting repeated 24-hour recalls for one weekday and one day during the weekend, which were then further converted into participants' Healthy Eating Index (HEI) 2015 scores. Meanwhile, an enzyme-linked immunosorbent assay was performed to determine the serum adiponectin level. A multiple regression analysis was performed to assess the association between the HEI 2015 score and serum adiponectin, adjusting for potential confounders. The mean HEI 2015 score was 33.2 ± 8.3 points, which was far below the recommended score of ≥ 80 points, while the mean serum adiponectin was 10.3 ± 4.1 μg/mL. Multiple linear regression testing showed that a one-point increase in the HEI 2015 score was significantly associated with an increase in the serum adiponectin level by 0.115 μg/mL after adjusting for exclusive breastfeeding history (β = 0.115; 95% CI = 0.010-0.221; p = 0.032). In conclusion, better adherence of young children to a healthy diet has a positive association with their adiponectin level. This result suggests that strengthening children's dietary quality from an early age by involving all parties in the children's environment (e.g., parents, teachers at school, policymakers) may help to reduce the risk of NCDs later on in childhood and during adult life.

Role of ceramides in the pathogenesis of diabetes mellitus and its complications

Diabetes mellitus (DM) is a systemic metabolic disease that affects 463 million adults worldwide and is a leading cause of cardiovascular disease, blindness, nephropathy, peripheral neuropathy, and lower-limb amputation. Lipids have long been recognized as contributors to the pathogenesis and pathophysiology of DM and its complications, but recent discoveries have highlighted ceramides, a class of bioactive sphingolipids with cell signaling and second messenger capabilities, as particularly important contributors to insulin resistance and the underlying mechanisms of DM complications. Besides their association with insulin resistance and pathophysiology of type 2 diabetes, evidence is emerging that certain species of ceramides are mediators of cellular mechanisms involved in the initiation and progression of microvascular and macrovascular complications of DM. Advances in our understanding of these associations provide unique opportunities for exploring ceramide species as potential novel therapeutic targets and biomarkers. This review discusses the links between ceramides and the pathogenesis of DM and diabetic complications and identifies opportunities for novel discoveries and applications.

Trajectories of Body Weight and Fat Mass in Relation to Incident Prediabetes in a Biracial Cohort of Free-Living Adults

Objectives

Obesity is a risk factor for type 2 diabetes (T2D), but prospective data relating adiposity measures to incident prediabetes are scant.

Methods

The Pathobiology of Prediabetes in A Biracial Cohort study followed normoglycemic African Americans (AA) and European Americans (EA) with parental history of T2D for the primary outcome of incident prediabetes (impaired fasting glucose and/or impaired glucose tolerance) for 5.5 years. Serial assessments included anthropometry and body fat composition. We analyzed weight, body mass index (BMI), waist, total, and abdominal fat mass in relation to incident prediabetes risk.

Results

Of the 376 subjects enrolled (217 AA, 159 EA; mean age 44.2 years, BMI 31.4 kg/m²), 343 (192 AA, 151 EA) had evaluable follow-up data. A total of 101 (52 AA, 49 EA) developed prediabetes during follow-up. Progressors to prediabetes had a mean baseline weight of 90.0 ± 20.4 kg versus 82.9 ± 21.7 kg among nonprogressors (P = 0.0036). During 5.5 (mean 2.62) years of follow-up, the weight change among nonprogressors was 0.63 ± 6.11 kg compared with 2.54 ± 6.91 kg among progressors (ANOVA P = 0.0072). Progressors also showed greater increases in total fat (P = 0.0015) and trunk fat (P = 0.0005) mass than nonprogressors. Adjusted for age and sex, the significant predictors of incident prediabetes were BMI (P = 0.0013), waist (P < 0.0001), total fat (P = 0.0025), and trunk fat (P < 0.0001) mass.

Conclusions

Among obese free-living offspring of parents with T2D, long-term normoglycemic status was associated with a weight gain of ~0.2 kg/y, whereas progression to prediabetes was associated with a weight gain of ~1 kg/y.

Insulin and Proinsulin Dynamics Progressively Deteriorate From Within the Normal Range Toward Impaired Glucose Tolerance

Context

Slight elevations in plasma glucose (PG) manifest in advance of diabetes onset, but abnormalities in immunoreactive insulin (IRI), proinsulin (Pro), and adiponectin dynamics during this stage remain poorly understood.

Objective

The objective of this work is to investigate whether IRI and Pro dynamics become abnormal as glucose tolerance deteriorates from within the normal range toward impaired glucose tolerance (IGT), as well as the relationship between PG, and these dynamics and serum adiponectin levels.

Design

A cross-sectional study was designed.

Setting

This study took place at Jichi Medical University in Japan.

Participants and Measurements

PG, IRI, and Pro levels were determined in 1311 young Japanese individuals (age < 40 years) with normal or IGT before and at 30, 60, and 120 minutes during a 75-g oral glucose tolerance test. Participants were assigned to 4 groups according to glucose tolerance, and then background factors, adiponectin levels, insulin sensitivity (SI), and insulin secretion (β) indexes were determined.

Results

PG levels as well as IRI and Pro levels 60 and 120 minutes after glucose-loading increased incrementally with deteriorating glucose tolerance. All measures of β and the SI measure index of insulin sensitivity (ISI)-Matsuda decreased incrementally. Serum adiponectin levels were not significantly different among the glucose tolerance groups, but were independently and negatively correlated with fasting glucose.

Conclusions

Early β decreased and postloading Pro levels became excessive in a progressive manner as glucose tolerance deteriorated from within the normal range toward IGT.

Pathobiology and Reversibility of Prediabetes in a Biracial Cohort (PROP-ABC) Study: design of lifestyle intervention

INTRODUCTION

Intensive lifestyle intervention (ILI) prevents progression from prediabetes to type 2 diabetes (T2D) but reversal of prediabetes is less well studied.

RESEARCH DESIGN AND METHODS

The overall objectives of the Pathobiology and Reversibility of Prediabetes in a Biracial Cohort (PROP-ABC) Study (ClinicalTrials.gov ID: NCT02027571) are to determine the natural history and reversibility of prediabetes. The study tests specific hypotheses on the patterns of progression to prediabetes among normoglycemic African-American (AA) and European-American (EA) offspring of parents with T2D; emergence of microvascular and macrovascular complications during transition from normal to impaired glucose regulation; significance of the 'metabolically healthy' obese phenotype; and effect of duration of the prediabetic state on its reversibility with lifestyle intervention. Participants who developed incident prediabetes were offered ILI and evaluated quarterly for 5 years. The primary outcome was restoration of normal glucose regulation (fasting plasma glucose <100 mg/dL and two-hour plasma glucose (2hrPG)<140 mg/dL).

RESULTS

Of the 223 subjects enrolled in the PROP-ABC Study, 158 participants with incident prediabetes started ILI. The mean age was 53.3±9.28 years; body mass index 30.6±6.70 kg/m²; 70% were female, 52.4% AA and 47.6% EA. The ILI program used goal setting, weight-based calorie restriction, physical activity (180 min/week), self-monitoring, and meal replacement. Monthly face-to-face (F2F) counseling sessions during the initial 6 months, and quarterly visits thereafter, were supplemented with electronic and postal contacts. Attendance at F2F sessions was highly correlated with weight loss (r=0.98, p<0.0001). Meal replacement induced ~5 kg weight loss within 3 months in participants with recrudescent weight pattern. Self-reported exercise minutes correlated with pedometer step counts (r=0.47, p<0.0001).

CONCLUSION

The PROP-ABC Study has demonstrated the feasibility of executing an ILI program designed to test reversibility of incident prediabetes in a biracial cohort.

Adipokines as key players in β cell function and failure

The growing prevalence of obesity and its related metabolic diseases, mainly Type 2 diabetes (T2D), has increased the interest in adipose tissue (AT) and its role as a principal metabolic orchestrator. Two decades of research have now shown that ATs act as an endocrine organ, secreting soluble factors termed adipocytokines or adipokines. These adipokines play crucial roles in whole-body metabolism with different mechanisms of action largely dependent on the tissue or cell type they are acting on. The pancreatic β cell, a key regulator of glucose metabolism due to its ability to produce and secrete insulin, has been identified as a target for several adipokines. This review will focus on how adipokines affect pancreatic β cell function and their impact on pancreatic β cell survival in disease contexts such as diabetes. Initially, the "classic" adipokines will be discussed, followed by novel secreted adipocyte-specific factors that show therapeutic promise in regulating the adipose-pancreatic β cell axis.

Regression from prediabetes to normal glucose regulation: State of the science

IMPACT STATEMENT

Prediabetes increases the risks of future type 2 diabetes (T2D) and vascular complications, risks that can be prevented by restoring normal glucose regulation (NGR). Few studies have pre-specified reversal of prediabetes and restoration of NGR as primary outcome, and current approaches that prevent T2D in people with prediabetes do not always reverse the prediabetes. The present review focuses on studies that have assessed reversal of the prediabetes, and discusses known and emerging predictors of prediabetes. We argue that fuller knowledge of such predictors could inform the discovery of novel, targeted interventions for reversing prediabetes.

Amino acid signature predictive of incident prediabetes: A case-control study nested within the longitudinal pathobiology of prediabetes in a biracial cohort

OBJECTIVE

Circulating branched-chain amino acids (BCAAs, isoleucine, leucine, valine) and aromatic amino acids (AAAs, tyrosine and phenylalanine) predicted type 2 diabetes mellitus (T2DM) risk in a Caucasian population. Here, we assessed amino acid levels in relation to incident prediabetes among initially normoglycemic African Americans (AA) and European Americans (EA).

RESEARCH DESIGN AND METHODS

Using a nested case-control design, we studied 70 adults (35 AA, 35 EA) who developed prediabetes (progressors) and 70 matched participants who maintained normoglycemia (nonprogressors) during 5.5 years of follow-up in the Pathobiology of Prediabetes in a Biracial Cohort study. Assessments included plasma amino acid levels, insulin sensitivity, and beta-cell function.

RESULTS

The total level of all 18 amino acid assayed was significantly associated with lean mass (r = 0.36, P < 0.0001), waist circumference (r = 0.27, P = 0.001), fasting plasma glucose (r = 0.24, P = 0.005), HOMA-IR (r = 0.22, P = 0.01) and HDL cholesterol (r = -0.18, P = 0.03). Individual amino acid levels were significantly associated with insulin sensitivity and insulin secretion. Compared with nonprogressors, progressors had higher baseline levels of asparagine and aspartic acid (P <0.0001), glutamine/glutamic acid (P = 0.005) and phenylalanine (P = 0.02), and lower histidine (P = 0.02) levels. In fully-adjusted logistic regression models, aspartic acid/asparagine (OR 2.72 [95% CI 1.91-3.87]) and histidine (OR 0.90 [95% CI 0.85-0.96]) were the only amino acids that significantly predicted incident prediabetes.

CONCLUSIONS

Baseline plasma aspartic acid and asparagine levels predicted progression to prediabetes, whereas histidine levels were protective of prediabetes risk. Thus, the amino acid signature associated with prediabetes in a diverse population may be distinct from that previously linked to T2DM in Caucasians.

Ethnic Disparities in Adiposity: Focus on Non-alcoholic Fatty Liver Disease, Visceral, and Generalized Obesity

PURPOSE OF REVIEW

Excessive adiposity has become a public health problem worldwide, contributing to the rise in obesity-related diseases and associated morbidity and mortality. This review details the relative significance of race/ethnicity as it pertains to adiposity and non-alcoholic fatty liver disease (NAFLD).

RECENT FINDINGS

Fat distribution remains a more reliable measure of adiposity than anthropometric measures, with visceral adipose tissue (VAT) associated with increased risk of cardiometabolic disease. While obesity is the most common risk factor for NAFLD, the racial/ethnic prevalence of obesity does not completely parallel NAFLD risk. Combating racial/ethnic disparities in obesity requires understanding differential risk among various groups. Hispanics are disproportionally impacted by NAFLD and have high rates of obesity, VAT, and insulin resistance (IR). This contrasts with Blacks, who have high prevalence of obesity and IR, accompanied by a paradoxically favorable lipid profile and low prevalence of VAT and NAFLD. Many features of adiposity and NAFLD are mediated by genetic and environmental factors, the latter being modifiable and the focus of interventions.

Seafood intake and the development of obesity, insulin resistance and type 2 diabetes

We provide an overview of studies on seafood intake in relation to obesity, insulin resistance and type 2 diabetes. Overweight and obesity development is for most individuals the result of years of positive energy balance. Evidence from intervention trials and animal studies suggests that frequent intake of lean seafood, as compared with intake of terrestrial meats, reduces energy intake by 4–9 %, sufficient to prevent a positive energy balance and obesity. At equal energy intake, lean seafood reduces fasting and postprandial risk markers of insulin resistance, and improves insulin sensitivity in insulin-resistant adults. Energy restriction combined with intake of lean and fatty seafood seems to increase weight loss. Marine n-3 PUFA are probably of importance through n-3 PUFA-derived lipid mediators such as endocannabinoids and oxylipins, but other constituents of seafood such as the fish protein per se, trace elements or vitamins also seem to play a largely neglected role. A high intake of fatty seafood increases circulating levels of the insulin-sensitising hormone adiponectin. As compared with a high meat intake, high intake of seafood has been reported to reduce plasma levels of the hepatic acute-phase protein C-reactive protein level in some, but not all studies. More studies are needed to confirm the dietary effects on energy intake, obesity and insulin resistance. Future studies should be designed to elucidate the potential contribution of trace elements, vitamins and undesirables present in seafood, and we argue that stratification into responders and non-responders in randomised controlled trials may improve the understanding of health effects from intake of seafood.

Adipokines Regulate the Expression of Tumor-Relevant MicroRNAs

BACKGROUND

Increasing prevalence of obesity requires the investigation of respective comorbidities, including tumor diseases like colorectal, renal, post-menopausal breast, prostate cancer, and leukemia. To date, molecular mechanisms of the malignant transformation of these peripheral tissues induced by obesity remain unclear. Adipose tissue secretes factors with hormone-like functions, the adipokines, and is therefore categorized as an endocrine organ. Current research demonstrates the ability of adipose tissue to alter DNA methylation and gene expression in peripheral tissues, probably affecting microRNA (miR) expression.

METHODS

Literature was analyzed for adipokine-regulated miRs. Many of these adipokine upregulated or downregulated miRs exert either oncogenic or anti-tumoral potential.

RESULTS

The three selected and analyzed adipokines, adiponectin, leptin, and resistin, induce more strongly oncogenic miRs and simultaneously reduce anti-tumoral miRs than vice versa. This effect is not only true for the pure number of regulated miRs, it is also the case by consideration of the abundance of the respective miR expression based on actual data sets derived from next-generation sequencing.

CONCLUSION

The link of obesity and cancer is analyzed under the aspect of adipokine-regulated miRs. At the same time the impact of miR abundance is considered as a regulatory variable. This context offers new strategies for tumor therapy and diagnostics.

Higher circulating adiponectin and lower orosomucoid were associated with postload glucose ≤70 mg/dL, a possible inverse marker for dysglycemia, in young Japanese women

OBJECTIVE

To examine whether serum adiponectin and orosomucoid were associated with postload glucose ≤70 mg/dL during an oral glucose tolerance test (OGTT), termed as postload low glycemia, a possible inverse marker for dysglycemia.

RESEARCH DESIGN AND METHODS

75 g OGTTs were performed with multiple postload glucose and insulin measurements over a 30-120 min period in 168 normal-weight Japanese women (18-24 years). Insulin resistance (IR) and β-cell function inferred from serum insulin kinetics during OGTT, fat mass and distribution by dual-energy X-ray absorptiometry (DXA), serum adiponectin and inflammatory markers were compared cross-sectionally between 39 women with and 129 women without postload low glycemia.

RESULTS

Of 168 women, 161 had normal glucose tolerance. Women with as compared with those without postload low glycemia had lower fasting and postload glycemia despite similar fasting and postload insulinemia. They had higher insulinogenic index (p=0.03) and lower adipose IR (a product of fasting free fatty acid and insulin, p=0.01), although DXA-derived general and central adiposity, the Matsuda Index and homeostasis model assessment-IR did not differ. In addition, they had higher adiponectin and lower orosomucoid (both p<0.001). Multivariate logistic regression analyses revealed that adiponectin (OR: 1.14, 95% CI 1.03 to 1.26, p=0.009) and orosomucoid (0.96, 0.93 to 0.97, p=0.008) were associated with postload low glycemia independently of adipose IR and insulinogenic index.

CONCLUSIONS

Higher adiponectin and lower orosomucoid were associated with 70 or lower mg/dL of postload glucose, a possible inverse marker for dysglycemia, in young women independently of DXA-derived fat mass and distribution, insulin secretion and IR.

Association of Adiponectin and rs1501299 of the ADIPOQ Gene with Prediabetes in Jordan

Type 2 diabetes mellitus (T2DM) is a worldwide health problem caused by resistance to insulin action. This chronic debilitating diseaseis preceded by a stage, known as prediabetes, in which a healthy lifestyle can delay the disease. The discovery of biochemical changes in prediabetes is important to identify individuals at risk of developing T2DM and in explaining disease pathogenesis. Adiponectin is secreted by fat cells and is linked with insulin resistance. Adiponectin levels are dysregulated in prediabetic subjects. This relationship had not been tested in Jordan. We recruited 130 subjects with prediabetes and 130 control subjects. We measured serum levels of adiponectin and genotyped subjects for three single nucleotide polymorphisms (SNPs) in the ADIPOQ gene; rs266729, rs1501299 and rs2241766. In multivariate analysis, we found that serum adiponectin lowers the risk of prediabetes (p = 0.002; odds ratio (OR), 0.764; 95% confidence interval (CI), 0.646⁻0.905). The rs1501299 SNP of the ADIPOQ gene was associated with prediabetes in our population (p = 0.041). Specifically, in multivariate analysis, the GT genotype of rs1501299 increased the risk of prediabetes (p = 0.010; OR, 2.350; 95% CI, 1.231⁻4.486) as well as the TT genotype (p = 0.006; OR, 4.774; 95% CI, 1.551⁻14.693). Our findings indicate that serum adiponectin and SNPs in the ADIPOQ gene are associated with prediabetes in Jordan.

Clinical Applications of Adiponectin Measurements in Type 2 Diabetes Mellitus: Screening, Diagnosis, and Marker of Diabetes Control

Background

Adipose tissue-derived adiponectin has pleiotropic protective effects with suppression of inflammatory and metabolic derangements that may result in insulin resistance, metabolic syndrome, type 2 diabetes mellitus (T2DM), and cardiovascular disease. The aim of this study was to evaluate adiponectin as a diagnostic marker of T2DM and diabetes control.

Methods

Fasting adiponectin, insulin, glucose, and HbA1c were determined in 376 patients with known T2DM and 575 subjects with undiagnosed diabetes but with family history of T2DM. Clinical and anthropometric data were recorded. Subjects were classified on the basis of degree of adiposity, insulin resistance (IR), and achievement of target HbA1c levels. Receiver operating characteristic (ROC) curve analysis was used to examine the diagnostic performance for undiagnosed DM.

Results

In undiagnosed subjects, adiponectin was significantly lower in subjects with IR and diabetic subjects compared with those without. The area under the adiponectin ROC curve for diagnosis of DM was 0.740. In known T2DM subjects, those with good control had significantly higher adiponectin (8.6 versus 7.4 μg/mL) compared to subjects with poor control.

Conclusions

Adiponectin levels are associated with better glycemic control and could be a useful adjunct for screening for IR and T2DM. Therapeutic measures that increase adiponectin levels might be valuable targets for improving diabetes control and decreasing complications.

Increased insulin sensitivity in individuals with neurofibromatosis type 1

Objects To compare insulin resistance (IR) and metabolic aspects of patients with neurofibromatosis type 1 (NF1) and individuals without the disease. Subjects and methods Forty patients with NF1 were matched by sex, age, and body mass index (BMI) to 40 controls from the community. Blood samples were collected for biochemical assessment. Homeostasis model assessment adiponectin (HOMA-AD), Homeostasis model assessment insulin resistance (HOMA-IR), and adiponectin/leptin ratio (ALR) were used to identify IR. Results The median HOMA-IR values were similar between the groups. However, the HOMA-AD value was significantly lower and the ALR significantly higher in the NF1 group. Fasting blood glucose (FBG), leptin, and visfatin levels of patients with NF1 were significantly lower, although adiponectin levels were significantly higher than those in the controls. Fasting insulin and blood glucose levels 2 hours after administration of 75 g of dextrose, glycated hemoglobin, and resistin showed no significant differences between groups. The HOMA-AD correlated with BMI, FBG, blood glucose levels 2 hours after administration of 75 g of dextrose, fasting insulin, glycated hemoglobin, adiponectin, leptin, visfatin, ALR, and HOMA-IR. The ALR correlated with BMI leptin, visfatin, and adiponectin. Conclusions Lower levels of FBG, leptin, visfatin, and HOMA-AD, and higher adiponectin levels and ALR may be related to increased insulin sensitivity and lower occurrence of type 2 diabetes mellitus in patients with NF1.

Ethnic Disparities in Endothelial Function and Its Cardiometabolic Correlates: The Pathobiology of Prediabetes in A Biracial Cohort Study

BACKGROUND

Endothelial function (EF) reflects the balance between vasodilatory and vasoconstrictive factors produced by (or acting on) the innermost lining of blood vessels. Endothelial dysfunction, an imbalance between these factors that favors vasoconstriction, has been associated with increased risk for cardiovascular disease. However, the influence of race/ethnicity and glycemic status on association between EF and cardiovascular risk factors remain to be clarified.

SUBJECTS AND METHODS

We assessed EF in relation to glycemia and cardiometabolic profile in African-American (AA) and European-American (EA) offspring of parents with type 2 diabetes (T2D), who are participants in the prospective pathobiology and reversibility of prediabetes in a biracial cohort (PROP-ABC) study. Assessments at enrollment included a 75 g oral glucose tolerance test (OGTT), blood pressure, anthropometry, body composition (DEXA), and lipid profile. Other assessments were insulin sensitivity and resting energy expenditure. EF was measured using flow-mediated vasodilation (EndoPAT 2000) and expressed as reactive hyperemia index (RHI).

RESULTS

We studied 190 subjects (100 AA, 90 C), mean age (±SD) 53.1 ± 9.1 years, and body mass index 30.6 ± 6.8 kg/m2. Based on OGTT data, 96 subjects (52 AA, 44 EA) had prediabetes and 94 subjects were normoglycemic (48 AA and 46 EA). The RHI was lower in AA than EA (2.17 ± 0.55 vs. 2.36 ± 0.72, P = 0.05) and in prediabetic than normoglycemic subjects (2.14 ± 0.62 vs. 2.38 ± 0.65, P = 0.013). Using RHI ≤ 1.68 as diagnostic cut-off, 19% of participants with prediabetes and 10% of normoglycemic participants had endothelial dysfunction (P = 0.04). In univariate models, RHI was positively associated with age and HDL cholesterol levels, and inversely associated with adiposity, diastolic blood pressure, and 2hr plasma glucose. The association between RHI and adiposity was stronger in men than women. The association between RHI and age, glucose and HDL cholesterol displayed marked ethnic disparities.

CONCLUSION

In our biracial cohort comprising offspring of parents with T2D, prediabetes increased the risk of endothelial dysfunction. However, the association between EF and cardiometabolic risk factors was significantly modified by ethnicity and gender. Our findings support current understanding of endothelial dysfunction as an early sensitive indicator of cardiometabolic risk.

Prediabetes and Cardiovascular Disease: Pathophysiology and Interventions for Prevention and Risk Reduction

Prediabetes is a state characterized by impaired fasting glucose or impaired glucose tolerance. This review discusses the pathophysiology and macrovascular complications of prediabetes. The pathophysiologic defects underlying prediabetes include insulin resistance, alpha- and beta-cell dysfunction, increased lipolysis, inflammation, and suboptimal incretin effect. Recent studies have revealed that the long-term complications of diabetes manifest in some people with prediabetes; these complications include microvascular and macrovascular disorders. Finally, we present an overview of randomized control trials aimed at preventing progression from prediabetes to type 2 diabetes and discuss their implications for macrovascular risk reduction.

Classical (adiponectin, leptin, resistin) and new (chemerin, vaspin, omentin) adipocytokines in patients with prediabetes

Background

In the last decade, there has been an increased interest toward fat tissue as an endocrine organ that secretes many cytokines and bioactive mediators that play a role in insulin sensitivity, inflammation, coagulation and the pathogenesis of atherosclerosis. The aim of this study was to investigate classical (adiponectin, leptin, resistin) and new (chemerin, vaspin, omentin) adipocytokine levels in subjects with prediabetes [impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT)] and obese subjects with normoglycemia.

Methods

In this study, 80 patients with a mean age of 50.4 ± 10.6 years were recruited, divided into two groups with similar age and body mass index (BMI) – with obesity and normoglycemia (n = 41) and with obesity and prediabetes (n = 39).

Results

Serum adiponectin levels were significantly higher in subjects with normoglycemia compared to patients with prediabetes. Adiponectin has a good discriminating power to distinguish between patients with and without insulin resistance in our study population [area under the curve (AUC) = 0.728, p = 0.002]. Other adipocytokine levels were not significantly different between the two groups. The patients with metabolic syndrome (MetS) had significantly lower levels of leptin compared to those without MetS (33.03 ± 14.94 vs. 40.24 ± 12.23 ng/mL) and this difference persisted after adjustment for weight and BMI. Receiver operating characteristic (ROC) analysis showed that low serum leptin can predict the presence of MetS (p = 0.03), AUC = 0.645.

Conclusion

Serum adiponectin is statistically higher in patients with normoglycemia compared to those with prediabetes and has a predictive value for distinguishing between patients with and without insulin resistance in the studied population. Serum leptin has a good predictive value for distinguishing between patients with and without MetS in the studied population.

Relationship Between Adiponectin and apoB in Individuals With Diabetes in the Atlantic PATH Cohort

Context

The increasing prevalence of obesity and diabetes greatly influences the risk for cardiovascular (CV) comorbidities and affects the quality of life of many people. However, the relationship among diabetes, obesity, and cardiovascular risk is complex and requires further investigation to understand the biological milieu connecting these conditions.

Objective

The aim of the current study was to explore the relationship between biological markers of adipose tissue function (adiponectin) and CV risk (apolipoprotein B) in body mass index (BMI)-matched participants with and without diabetes.

Design

Nested case-control study.

Setting

The Atlantic Partnership for Tomorrow's Health (PATH) cohort represents four Atlantic Canadian provinces: Newfoundland and Labrador, New Brunswick; Nova Scotia; and Prince Edward Island.

Participants

The study population (n = 480) was aged 35 to 69 years, 240 with diabetes and 240 without diabetes.

Main Outcome Measures

Groups with and without diabetes were matched for sex and BMI. Both measured and self-reported data were used to examine disease status, adiposity, and lifestyle factors. Immunoassays were used to measure plasma markers.

Results

In these participants, plasma adiponectin levels were lower among those with diabetes than those without diabetes; these results were sex-specific, with a strong relationship seen in women. In contrast, in participants matched for sex and adiposity, plasma apoB levels were similar between participants with and those without diabetes.

Conclusion

Measures of adiposity were higher in participants with diabetes. However, when matched for adiposity, the adipokine adiponectin exhibited a strong inverse association with diabetes.

Relationships between blood pressure and blood glucose among offspring of parents with type 2 diabetes: Prediction of incident dysglycemia in a biracial cohort

AIMS

We assessed blood pressure (BP) and blood glucose (BG) values in healthy subjects, and examined baseline BP as a predictor of incident prediabetes during follow-up.

METHODS

Participants in the Pathobiology of Prediabetes in a Biracial Cohort (POP-ABC) study underwent screening assessments (anthropometry, BP, OGTT) and were stratified into normal BP (NBP), prehypertension, or hypertension, and normal glucose regulation (NGR), prediabetes (IFG/IGT), or type 2 diabetes (T2D) status. NGR subjects who met all inclusion criteria were enrolled in a 5-yr prospective study, with the primary outcome of incident prediabetes.

RESULTS

We screened 602 adults (341 black, 261 white) and enrolled 343 (193 black, 150 white) for prospective follow-up. Systolic and diastolic BP correlated significantly with fasting and nonfasting BG (P=0.003-<0.0001). Compared to NGR group, more prediabetic subjects had prehypertension (42.5% vs. 36.2%) and fewer had NBP (35.9% vs. 48.6%) (P=0.009). During ~5years of follow-up, 26.3% of NBP and 35.7% of prehypertensive subjects developed prediabetes (P=0.02). Kaplan-Meier analysis showed higher probability of incident prediabetes among participants with prehypertension compared to NBP during ~5years of follow-up (P=0.0012).

CONCLUSIONS

In our biracial cohort, BP and BG values were significantly correlated, and BP status predicted incident prediabetes among initially normoglycemic individuals. These findings suggest co-evolution of factors involved in the dysregulation of BP and BG.

Sex-Specific Modulation of Fetal Adipogenesis by Gestational Bisphenol A and Bisphenol S Exposure

The endocrine-disrupting chemical bisphenol A (BPA) increases adipose tissue mass in vivo and promotes adipogenesis in vitro; however, mechanisms explaining BPA's obesogenic effect remain unknown. We investigated the effects of gestational BPA and its analog, bisphenol S (BPS), exposure on the adipogenic differentiation ability of fetal preadipocytes and the role of endoplasmic reticulum stress in regulating this process. Pregnant sheep (n = 7 to 8 per group) mated to the same male were exposed to BPA or BPS from days 30 to 100 of gestation; pregnancies were terminated 20 days later. Adipose tissue was harvested and fetal preadipocytes isolated. Adipose tissue gene expression, adipocyte size, preadipocyte gene expression, adipogenic differentiation, and dynamic expression of genes involved in adipogenesis and endoplasmic reticulum stress were assessed. Gestational BPA enhanced adipogenic differentiation in female, but not male, preadipocytes. The unfolded protein response (UPR) pathway was upregulated in BPA-exposed female preadipocytes supportive of a higher endoplasmic reticulum stress. Increased expression of estradiol receptor 1 and glucocorticoid receptor in female preadipocytes suggests that this may be a potential cause behind the sex-specific effects observed upon BPA exposure. Gestational BPS affected adipogenic terminal differentiation gene expression in male preadipocytes, but not adipogenic differentiation potential. We demonstrate that gestational BPA exposure can modulate the differentiation ability of fetal preadipocytes. UPR upregulation in gestationally BPA-exposed female preadipocytes may contribute to the increased preadipocyte's adipogenic ability. The marked sex-specific effect of BPA highlights higher susceptibility of females to bisphenol A and potentially, a higher risk to develop obesity in adulthood.

Identification of novel biomarkers to monitor β-cell function and enable early detection of type 2 diabetes risk

A decline in β-cell function is a prerequisite for the development of type 2 diabetes, yet the level of β-cell function in individuals at risk of the condition is rarely measured. This is due, in part, to the fact that current methods for assessing β-cell function are inaccurate, prone to error, labor-intensive, or affected by glucose-lowering therapy. The aim of the current study was to identify novel circulating biomarkers to monitor β-cell function and to identify individuals at high risk of developing β-cell dysfunction. In a nested case-control study from the Relationship between Insulin Sensitivity and Cardiovascular disease (RISC) cohort (n = 1157), proteomics and miRNA profiling were performed on fasting plasma samples from 43 individuals who progressed to impaired glucose tolerance (IGT) and 43 controls who maintained normal glucose tolerance (NGT) over three years. Groups were matched at baseline for age, gender, body mass index (BMI), insulin sensitivity (euglycemic clamp) and β-cell glucose sensitivity (mathematical modeling). Proteomic profiling was performed using the SomaLogic platform (Colorado, USA); miRNA expression was performed using a modified RT-PCR protocol (Regulus Therapeutics, California, USA). Results showed differentially expressed proteins and miRNAs including some with known links to type 2 diabetes, such as adiponectin, but also novel biomarkers and pathways. In cross sectional analysis at year 3, the top differentially expressed biomarkers in people with IGT/ reduced β-cell glucose sensitivity were adiponectin, alpha1-antitrypsin (known to regulate adiponectin levels), endocan, miR-181a, miR-342, and miR-323. At baseline, adiponectin, cathepsin D and NCAM.L1 (proteins expressed by pancreatic β-cells) were significantly lower in those that progressed to IGT. Many of the novel prognostic biomarker candidates were within the epithelial-mesenchymal transition (EMT) pathway: for example, Noggin, DLL4 and miR-181a. Further validation studies are required in additional clinical cohorts and in patients with type 2 diabetes, but these results identify novel pathways and biomarkers that may have utility in monitoring β-cell function and/ or predicting future decline, allowing more targeted efforts to prevent and intercept type 2 diabetes.