Characterization of insulin secretion and resistance in type 2 diabetes of adolescents

Autoantibodies against beta cells to predict early insulin requirements in pediatric patients with clinically diagnosed type 2 diabetes

BACKGROUND

Autoimmunity has emerged as a probable disease modifier in patients with clinically diagnosed type 2 diabetes mellitus (T2DM), that is, patients who have insulin resistance, obesity, and other cardiovascular risk factors, suggesting that the presence of glutamic acid decarboxylase (anti-GAD65), islet antigen 2 (anti-IA2), and zinc transporter 8 (anti-Zn8T) antibodies could have deleterious effects on beta cell function, causing failure and earlier requirement for insulin treatment.

AIM

To evaluate anti-GAD65, anti-IA2 and anti-Zn8T as predictors of early insulin requirement in adolescents with a clinical diagnosis of T2DM.

METHODS

This was a case-control study in patients with clinically diagnosed with T2DM (68 cases and 64 controls with and without early insulin dependence respectively), male and female, aged 12-18 years. Somatometry, blood pressure, glucose, insulin, C-peptide, glycated hemoglobin A1c, and lipid profiles were assessed. ELISA was used to measure anti-GAD65, anti-IA2, and anti-Zn8T antibodies. Descriptive statistics, Pearson's χ 2 test, Student's t test, and logistic regression was performed. P < 0.05 was considered statistically significant.

RESULTS

There were 132 patients (53.8% female), with a mean age was 15.9 ± 1.3 years, and there was a disease evolution time of 4.49 ± 0.88 years. The presence of anti-GAD65, anti-IA2, and anti-Zn8T positivity was found in 29.5%, 18.2%, and 15.9%, respectively. Dividing the groups by early or no insulin dependence showed that the group with insulin had a higher frequency of antibody positivity: anti-GAD65 odds ratio (OR): 2.42 (1.112-5.303, P = 0.026); anti-IA2: OR: 1.55 (0.859-2.818, P = 0.105); and anti-Zn8T: OR: 7.32 (2.039-26.279, P = 0.002).

CONCLUSION

Anti-GAD65 positivity was high in our study. Anti-GAD65 and anti-Zn8T positivity showed a significantly depleted beta cell reserve phenotype, leading to an increased risk of early insulin dependence.

Challenges and pitfalls of youth-onset type 2 diabetes

The incidence and prevalence of youth-onset type 2 diabetes mellitus (T2DM) are increasing. The rise in frequency and severity of childhood obesity, inclination to sedentary lifestyle, and epigenetic risks related to prenatal hyperglycemia exposure are important drivers of the youth-onset T2DM epidemic and might as well be responsible for the early onset of diabetes complications. Indeed, youth-onset T2DM has a more extreme metabolic phenotype than adult-onset T2DM, with greater insulin resistance and more rapid deterioration of beta cell function. Therefore, intermediate complications such as microalbuminuria develop in late childhood or early adulthood, while end-stage complications develop in mid-life. Due to the lack of efficacy and safety data, several drugs available for the treatment of adults with T2DM have not been approved in youth, reducing the pharmacological treatment options. In this mini review, we will try to address the present challenges and pitfalls related to youth-onset T2DM and summarize the available interventions to mitigate the risk of microvascular and macrovascular complications.

In vitro and in silico inhibitory validation of Tapinanthus cordifolius leaf extract on alpha-glucosidase in the management of type 2 diabetes

The anti-diabetic properties of medicinal plants are becoming more widely recognized. To identify potential anti-diabetic agents for diabetes drug discovery, the current study used in vitro and in silico approaches to assess the alpha glucosidase inhibitory activities of Tapinanthus cordifolius (TC) leaf extracts and its bioactive components respectively. In vitro alpha glucosidase inhibitory assay was carried out on TC extract and fractions at various concentrations (50-1600 µg/mL), and the compounds with alpha glucosidase inhibitory potentials were identified using molecular docking, pharmacophore modelling, and molecular dynamics simulation. The crude extract exhibited the highest activity with an IC50 value of 248 μg/mL. Out of the 42 phytocompounds of the extract, α-Tocopherol-β-d-mannoside gave the lowest binding energy of -6.20 Kcal/mol followed by, 5-Ergosterol (-5.46 kcal/mol), Acetosyringone (-4.76 kcal/mol), and Benzaldehyde, 4-(Ethylthio)-2,5-Dimethoxy-(-4.67 kcal/mol). The selected compounds interacted with critical active site amino acid residues of alpha-glucosidase, just like the reference ligand. Molecular dynamics simulation revealed the formation of a stable complex between α-glucosidase and α-Tocopherol-β-d-mannoside, with ASP 564 sustaining two hydrogen bond connections for 99.9 and 75.0% of the simulation duration, respectively. Therefore, the selected TC compounds, especially α-Tocopherol-β-d-mannoside might be explored for future research and development as diabetic medicines.Communicated by Ramaswamy H. Sarma.

Coronary Plaque Characteristics and Underlying Mechanism of Acute Coronary Syndromes in Different Age Groups of Patients With Diabetes

BACKGROUND

High cardiovascular mortality has been reported in young patients with diabetes. However, the underlying pathology in different age groups of patients with diabetes has not been studied.

METHODS AND RESULTS

The aim of this study was to investigate the plaque characteristics and underlying pathology of acute coronary syndrome in different age groups of patients with or without diabetes in a large cohort. Patients who presented with acute coronary syndrome and underwent preintervention optical coherence tomography imaging were included. Culprit plaque was classified as plaque rupture, plaque erosion, or calcified plaque and stratified into 5 age groups. Plaque characteristics including features of vulnerability were examined by optical coherence tomography. Among 1394 patients, 482 (34.6%) had diabetes. Patients with diabetes, compared with patients without diabetes, had a higher prevalence of lipid-rich plaque (71.2% versus 64.8%, P=0.016), macrophage (72.0% versus 62.6%, P<0.001), and cholesterol crystal (27.6% versus 19.7%, P<0.001). Both diabetes and nondiabetes groups showed a decreasing trend in plaque erosion with age (patients with diabetes, P=0.020; patients without diabetes, P<0.001). Patients without diabetes showed an increasing trend with age in plaque rupture (P=0.004) and lipid-rich plaque (P=0.018), whereas patients with diabetes had a high prevalence of these vulnerable features at an early age that remained high across age groups.

CONCLUSIONS

Patients without diabetes showed an increasing trend with age in plaque rupture and lipid-rich plaque, whereas patients with diabetes had a high prevalence of these vulnerable features at an early age. These results suggest that atherosclerotic vascular changes with increased vulnerability start at a younger age in patients with diabetes.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifiers: NCT04523194, NCT03479723. URL: https://www.umin.ac.jp/ctr/. Unique identifier: UMIN000041692.

Genetics of diabetes

Diabetes mellitus is a complicated disease characterized by a complex interplay of genetic, epigenetic, and environmental variables. It is one of the world's fastest-growing diseases, with 783 million adults expected to be affected by 2045. Devastating macrovascular consequences (cerebrovascular disease, cardiovascular disease, and peripheral vascular disease) and microvascular complications (like retinopathy, nephropathy, and neuropathy) increase mortality, blindness, kidney failure, and overall quality of life in individuals with diabetes. Clinical risk factors and glycemic management alone cannot predict the development of vascular problems; multiple genetic investigations have revealed a clear hereditary component to both diabetes and its related complications. In the twenty-first century, technological advancements (genome-wide association studies, next-generation sequencing, and exome-sequencing) have led to the identification of genetic variants associated with diabetes, however, these variants can only explain a small proportion of the total heritability of the condition. In this review, we address some of the likely explanations for this "missing heritability", for diabetes such as the significance of uncommon variants, gene-environment interactions, and epigenetics. Current discoveries clinical value, management of diabetes, and future research directions are also discussed.

Youth-onset type 2 diabetes mellitus: an urgent challenge

The incidence and prevalence of youth-onset type 2 diabetes mellitus (T2DM) and its complications are increasing worldwide. Youth-onset T2DM has been reported in all racial and ethnic groups, but Indigenous peoples and people of colour are disproportionately affected. People with youth-onset T2DM often have a more aggressive clinical course than those with adult-onset T2DM or those with type 1 diabetes mellitus. Moreover, the available treatment options for children and adolescents with T2DM are more limited than for adult patients. Intermediate complications of youth-onset T2DM, such as increased albuminuria, often develop in late childhood or early adulthood, and end-stage complications, including kidney failure, develop in mid-life. The increasing frequency, earlier onset and greater severity of childhood obesity in the past 50 years together with increasingly sedentary lifestyles and an increasing frequency of intrauterine exposure to diabetes are important drivers of the epidemic of youth-onset T2DM. The particularly high risk of the disease in historically disadvantaged populations suggests an important contribution of social and environmental factors, including limited access to high-quality health care, healthy food choices and opportunities for physical activity as well as exposure to stressors including systemic racism and environmental pollutants. Understanding the mechanisms that underlie the development and aggressive clinical course of youth-onset T2DM is key to identifying successful prevention and management strategies.

Diabetogenic viruses: linking viruses to diabetes mellitus

Diabetes Mellitus (DM) is a group of chronic metabolic diseases distinguished by elevated glycemia due to the alterations in insulin metabolism. DM is one of the most relevant diseases of the modern world, with high incidence and prevalence worldwide, associated with severe systemic complications and increased morbidity and mortality rates. Although genetic factors and lifestyle habits are two of the main factors involved in DM onset, viral infections, such as enteroviruses, cytomegalovirus, hepatitis C virus, human immunodeficiency virus, severe acute respiratory syndrome coronavirus 2, among others, have been linked as triggers of type 1 (T1DM) and type 2 (T2DM) diabetes. Over the years, various groups identified different mechanisms as to how viruses can promote these metabolic syndromes. However, this field is still poorly explored and needs further research, as millions of people live with these pathologies. Thus, this review aims to ex-plore the different processes of how viruses can induce DM and their contribution to the prevalence and incidence of DM worldwide.

Type 2 diabetes and bone fragility in children and adults

Type 2 diabetes (T2D) is a global epidemic disease. The prevalence of T2D in adolescents and young adults is increasing alarmingly. The mechanisms leading to T2D in young people are similar to those in older patients. However, the severity of onset, reduced insulin sensitivity and defective insulin secretion can be different in subjects who develop the disease at a younger age. T2D is associated with different complications, including bone fragility with consequent susceptibility to fractures. The purpose of this systematic review was to describe T2D bone fragility together with all the possible involved pathways. Numerous studies have reported that patients with T2D show preserved, or even increased, bone mineral density compared with controls. This apparent paradox can be explained by the altered bone quality with increased cortical bone porosity and compr-omised mechanical properties. Furthermore, reduced bone turnover has been described in T2D with reduced markers of bone formation and resorption. These findings prompted different researchers to highlight the mechanisms leading to bone fragility, and numerous critical altered pathways have been identified and studied. In detail, we focused our attention on the role of microvascular disease, advanced glycation end products, the senescence pathway, the Wnt/β-catenin pathway, the osteoprotegerin/receptor-activator of nuclear factor kappa B ligand, osteonectin and fibroblast growth factor 23. The understanding of type 2 myeloid bone fragility is an important issue as it could suggest possible interventions for the prevention of poor bone quality in T2D and/or how to target these pathways when bone disease is clearly evident.

The Theory of Hyperlipidemic Memory of Type 1 Diabetes

A literature search was conducted to identify publications addressing the early phases of lipid phenotypes in children and adults with either type 1 diabetes or type 2 diabetes. Medline, EMBASE, and Ovid were searched using the following search terms: clinical remission, partial remission, partial clinical remission, honeymoon phase, C-peptide, type 1 or 2 diabetes, children, pediatric type 1 or 2 diabetes, and paediatrics type 1 or 2 diabetes, adults, adult type 1 or type 2 diabetes. Partial clinical remission (PR) of type 1 diabetes (T1D) is characterized by continued endogenous production of insulin and C-peptide following the diagnosis and the introduction of exogenous insulin therapy. PR is associated with improved glycemic control and reduced prevalence of diabetes complications. The theory of hyperglycemic memory was proposed to explain this concept of improved glycemic outcomes in remitters (those who experienced PR) versus non-remitters (those who did not experience PR). However, this theory is incomplete as it does not explain the dichotomy in early lipid phenotypes in T1D based on PR status, which is an understudied area in diabetology and lipidology. To fill this knowledge gap, we propose the Theory of Hyperlipidemic Memory of T1D. This theory is premised on our 5-year research on early post-diagnostic dichotomy in lipid phenotypes between remitters and non-remitters across the lifespan. It provides a more rigorous explanation for the differences in lifelong atherosclerotic cardiovascular disease (ASCVD) risk between remitters and non-remitters. We conducted 4 clinical studies in pediatric and adult subjects with diabetes mellitus to characterize the particulars of the hyperlipidemic memory. In the first investigation, we explored the impact of the presence or absence of PR on lipid parameters in children and adolescents with T1D. In the second, we investigated whether pubertal maturation influenced our findings in T1D; and whether these findings could be replicated in healthy, non-diabetic children and adolescents. In the third, we leveraged our findings from T1D and controls to investigate the mechanisms of early lipid changes in T2D by comparing the earliest lipid phenotype of subjects with type 2 diabetes (T2D) to those of remitters, non-remitters, and controls. In the fourth, we investigated the impact of PR on the earliest lipid phenotypes in adults with T1D and compared these early lipid data to those of T2D subjects and controls. This body of work across the lifespan in children, adolescents, and adults supports the Theory of Hyperlipidemic Memory. This new theory clarifies why PR largely determines the risks for early-phase dyslipidemia, mid-term microvascular disease risk, and long-term ASCVD risk in subjects with T1D.

Association of β-cell function and insulin resistance with pediatric type 2 diabetes among Chinese children

BACKGROUND

In addition to insulin resistance, impaired insulin secretion has recently been identified as a crucial factor in the pathogenesis of type 2 diabetes mellitus (T2DM). Scarce clinical data exist for pediatric T2DM.

AIM

To investigate the association of β-cell function and insulin resistance with pediatric T2DM in the first Chinese multicenter study.

METHODS

This multicenter cross-sectional study included 161 newly diagnosed T2DM children and adolescents between January 2017 and October 2019. Children with normal glycemic levels (n = 1935) were included as healthy control subjects. The homeostasis models (HOMAs) were used to assess the β-cell function (HOMA2-%B) and insulin resistance (HOMA2-IR) levels. The HOMA index was standardized by sex and age. We performed logistic regression analysis to obtain odds ratios (ORs) for T2DM risk using the standardized HOMA index, adjusted for confounding factors including sex, Tanner stage, T2DM family history, body mass index z-score, and lipid profile.

RESULTS

The male-female ratio of newly diagnosed T2DM patients was 1.37:1 (OR = 2.20, P = 0.011), and the mean ages of onset for boys and girls were 12.5 ± 1.9 years and 12.3 ± 1.7 years, respectively. The prevalence of related comorbidities including obesity, elevated blood pressure, and dyslipidemia was 58.2%, 53.2%, and 80.0%, respectively. The T2DM group had lower HOMA2-%B levels (P < 0.001) and higher HOMA2-IR levels (P < 0.001) than the control group. Both the decrease in HOMA2-%B z-score (OR = 8.40, 95%CI: 6.40–11.02, P < 0.001) and the increase in HOMA2-IR z-score (OR = 1.79, 95%CI: 1.60–2.02, P < 0.001) were associated with a higher risk of T2DM, and the decrease in HOMA2-%B z-score always had higher ORs than the increase in HOMA2-IR z-score after adjusting for confounding factors.

CONCLUSION

Besides insulin resistance, β-cell function impairment is also strongly associated with Chinese pediatric T2DM. Gender difference in susceptibility and high comorbidities warrant specific T2DM screening and prevention strategies in Chinese children.

Type 2 diabetes in pediatrics

Type 2 diabetes (T2D) in adolescents has become an increasing health concern throughout the world and its prevention and screening should be implemented in pediatric care. As clinical features at presentation, in some cases can be similar to type 1 diabetes and family history can be in favour of a monogenic form of diabetes, it is pivotal for physicians to be aware of youth-onset T2D specificities to ensure an accurate diagnosis. The global increase of overweight and obesity can complicate the diagnostic process and makes it essential to apply a systematic approach to each new diagnosis. Microvascular complications may be present at the time of diagnosis and chronic complications are frequent and need to be screened regularly. Regular screening of comorbidities should also be performed. Childhood T2D should be followed up by pediatric diabetes units to avoid diagnostic errors and delay in care. A multidisciplinary approach, by an experienced team, is pivotal to provide treatment options targeting the unique needs of pediatric patients. Treatment programs must include the whole family and address all the aspects of the care (lifestyle, pharmacological therapy, psychological aspects, complications and comorbidities). An organized process of transition to adult care is essential.

The Capacity to Secrete Insulin Is Dose-Dependent to Extremely High Glucose Concentrations: A Key Role for Adenylyl Cyclase

Insulin secretion is widely thought to be maximally stimulated in glucose concentrations of 16.7-to-30 mM (300-to-540 mg/dL). However, insulin secretion is seldom tested in hyperglycemia exceeding these levels despite the Guinness World Record being 147.6 mM (2656 mg/dL). We investigated how islets respond to 1-h exposure to glucose approaching this record. Insulin secretion from human islets at 12 mM glucose intervals dose-dependently increased until at least 72 mM glucose. Murine islets in 84 mM glucose secreted nearly double the insulin as in 24 mM (p < 0.001). Intracellular calcium was maximally stimulated in 24 mM glucose despite a further doubling of insulin secretion in higher glucose, implying that insulin secretion above 24 mM occurs through amplifying pathway(s). Increased osmolarity of 425-mOsm had no effect on insulin secretion (1-h exposure) or viability (48-h exposure) in murine islets. Murine islets in 24 mM glucose treated with a glucokinase activator secreted as much insulin as islets in 84 mM glucose, indicating that glycolytic capacity exists above 24 mM. Using an incretin mimetic and an adenylyl cyclase activator in 24 mM glucose enhanced insulin secretion above that observed in 84 mM glucose while adenylyl cyclase inhibitor reduced stimulatory effects. These results highlight the underestimated ability of islets to secrete insulin proportionally to extreme hyperglycemia through adenylyl cyclase activity.

Early-onset of type 2 diabetes mellitus is a risk factor for diabetic nephropathy progression: a biopsy-based study

Several studies show that patients with early-onset diabetes have higher risk of diabetic complications than those diagnosed in middle age. However, whether early-onset of type 2 diabetes mellitus (T2DM) is a risk factor for diabetic nephropathy (DN) progression remains unclear, especially a lack of data in biopsy-confirmed cohort. In This study, we enrolled 257 patients with T2DM and biopsy-confirmed DN to investigate the role of early-onset T2DM in DN progression. Participants were divided into two groups according to the age of T2DM diagnosis: early-onset group (less than 40 years) and later-onset group (40 years or older). We found that patients with early-onset T2DM had higher glomerular grades and arteriolar hyalinosis scores than those in later-onset group. After adjusted for confounding factors, early-onset of T2DM remained an independent predictor of end-stage renal disease (ESRD) for patients with DN. In conclusion, although with the comparable renal function and proteinuria, patients with early-onset T2DM and DN had worse renal pathological changes than those with later-onset. Early-onset of T2DM might be an important predictor of ESRD for patients with DN, which called more attention to early supervision and prevention for patients with early-onset T2DM and DN.

Oral minimal model-based estimates of insulin sensitivity in obese youth depend on oral glucose tolerance test protocol duration

Introduction

The Oral Minimal Model (OMM), a differential-equations based mathematical model of glucose-insulin dynamics, utilizes data from a frequently sampled oral glucose tolerance test (OGTT) to quantify insulin sensitivity ( S I ). OMM-based estimates of S I can detect differences in insulin resistance (IR) across population groups and quantify effects of clinical or behavioral interventions. These estimates of S I have been validated in healthy adults using data from OGTTs with durations from 2 to 7 h. However, data demonstrating how protocol duration affects S I estimates in highly IR populations such as adolescents with obesity are limited.

Methods

A 6-h frequently sampled OGTT was performed in adolescent females with obesity. Two, 3-, and 4- hour implementations of OMM assuming an exponentially-decaying rate of glucose appearance beyond measured glucose concentrations were compared to the 6-h implementation. A 4- hour OMM implementation with truncated data (4h Tr) was also considered.

Results

Data from 68 participants were included (age 15.8 ± 1.2 years, BMI 35.4 ± 5.6 kg/m²). Although S I values were highly correlated for all implementations, they varied with protocol duration (2h: 2.86 ± 3.31, 3h: 2.55 ± 2.62, 4h: 2.81 ± 2.59, 4h tr: 3.13 ± 3.14, 6h: 3.06 ± 2.85 x 10^-4 dl/kg/min per U/ml). S I estimates based on 2 or 3 h of data underestimated S I values, whereas 4-h S I estimates more closely approximated 6-h S I values.

Discussion

These results suggest that OGTT protocol duration should be considered when implementing OMM to estimate S I in adolescents with obesity and other IR populations.

Association Between Age at Diagnosis of Type 2 Diabetes and Cardiovascular Diseases: A Nationwide, Population-Based, Cohort Study

OBJECTIVES

Nationwide studies focusing on the impact of early-onset type 2 diabetes and obesity on the development of cardiovascular diseases (CVD) are limited in China. We aimed to investigate the association between age at diagnosis of type 2 diabetes and the risk of CVD, and to further examine the modifying effect of obesity on this association among Chinese adults.

METHODS

This study included 23,961 participants with previously diagnosed diabetes from a large nationwide population-based cohort study across mainland China. With an interviewer-assisted questionnaire, we collected detailed information on CVDs. Logistic regression analysis was used to evaluate the risk of CVDs associated with age at diagnosis of diabetes.

RESULTS

Compared with patients with late-onset diabetes (≥60 years), those with earlier-onset diabetes had increased risks for CVD, with adjusted ORs (95% CIs) of 1.72 (1.36-2.17), 1.52 (1.31-1.75) and 1.33 (1.19-1.48) for patients diagnosed aged <40, 40-49 and 50-59 years, respectively. Each 5-year earlier age at diagnosis of type 2 diabetes was significantly associated with 14% increased risk of CVD (OR, 1.14; 95%CI, 1.11-1.18). This association was more prominent for patients with obesity than those with normal body mass index (BMI). Significant interaction was detected between age at diagnosis and BMI categories on CVD risk (P for interaction=0.0457).

CONCLUSION

Early-onset type 2 diabetes was significantly associated with higher risk of CVD, and this association was more prominent among patients with obesity.

The roles of vitamin D and cathelicidin in type 1 diabetes susceptibility

Type 1 diabetes has an increasingly greater incidence and prevalence with no cure available. Vitamin D supplementation is well documented to reduce the risk of developing type 1 diabetes. Being involved in the modulation of cathelicidin expression, the question whether cathelicidin may be one of the underlying cause arises. Cathelicidin has been implicated in both the development and the protection against type 1 diabetes by mediating the interplay between the gut microbiome, the immune system and β cell function. While its potential on type 1 diabetes treatment seems high, the understanding of its effects is still limited. This review aims to contribute to a more comprehensive understanding of the potential of vitamin D and cathelicidin as adjuvants in type 1 diabetes therapy.

Mechanisms and early patterns of dyslipidemia in pediatric type 1 and type 2 diabetes

Objectives The is no consensus on the early patterns of lipid-based cardiovascular disease (CVD) risk in youth with either type 1 diabetes (T1D) or type 2 diabetes (T2D). The aim was todetermine the differences in CVD risk, using lipid profiles, in children and adolescents with either T1D or T2D at the time of their first lipid assessment, after stratifying the T1D cohort into remitters and non-remitters based on their honeymoon history. Methods A cross-sectional study of 249 subjects consisting of 73 controls, 53 T2D subjects, and 123 T1D subjects stratified into remitters (n=44), and non-remitters (n=79). Partial clinical remission (PCR) was defined as insulin-dose adjusted HbA1c of ≤9. Pubertal status was determined by Tanner staging. Results After adjusting for age, sex, BMI, race, and pubertal status, T2D patients had significantly higher LDL-C compared to the controls (p=0.022), the remitters (p=0.029), but not the non-remitters (103.1 ± 5.9 mg/dL vs. 91.4 ± 4.2 mg/dL, p=0.49). Similarly, T2D patients had significantly higher non-HDL-C compared to the controls (p=0.006), the remitters (p=0.0002), but not the non-remitters (137.6 ± 7.1 mg/dL vs. 111.71 ± 5.0 mg/dL, p=0.053). Total cholesterol was also significantly higher in T2D patients compared to the controls (p=0.0005), the remitters (p=0.006) but not the non-remitters (183.5 ± 6.6 mg/dL vs. 166.2 ± 4.8 mg/dL, p=0.27). Conclusions Lack of the honeymoon phase in children and adolescents with T1D confers early and significantly increased lipid-based cardiovascular risk to these patients that is similar to the elevated cardiovascular risk seen in T2D.

Good agreement between hyperinsulinemic-euglycemic clamp and 2 hours oral minimal model assessed insulin sensitivity in adolescents

BACKGROUND/OBJECTIVE

Rates of dysglycemia are increasing in youth, secondary to obesity and decreased insulin sensitivity (IS) in puberty. The oral minimal model (OMM) has been developed in order to measure IS using an easy oral glucose load, such as an oral glucose tolerance test (OGTT), instead of an hyperinsulinemic-euglycemic clamp (HE-clamp), a more invasive and time-consuming procedure. However, this model, following a standard 2 hour- OGTT has never been validated in youth, a population known for a different physiologic response to OGTT than adults. Thus, we compared IS measurements obtained from OMM following a 2-hour OGTT to HE-clamp and isotope tracer-assessed tissue IS in adolescents. We also compared the liver/muscle-specific IS from HE-clamp with other liver/muscle-specific IS surrogates following an OGTT previously validated in adults.

METHODS

Secondary analysis of a cross-sectional study. Adolescent girls with (n = 26) and without (n = 7) polycystic ovary syndrome (PCOS) (14.6 ± 1.7 years; BMI percentile 23.3%-98.2%) underwent a 2-hour 75 g OGTT and a 4-phase HE-clamp. OMM IS (Si), dynamic Si (Si^d ) and other OGTT-derived muscle and liver IS indices were correlated with HE-clamp tissue-specific IS.

RESULTS

OMM Si and Si^d correlated with HE-clamp-measured peripheral IS (r = 0.64, P <.0001 and r = 0.73; P <.0001, respectively) and the correlation coefficient trended higher than the Matsuda index (r = 0.59; P =.003). The other tissue-specific indices were poorly correlated with their HE-clamp measurements.

CONCLUSION

In adolescent girls, the 2-hour OMM provided the best estimate of peripheral IS. Additional surrogates for hepatic IS are needed for youth.

One elevated oral glucose tolerance test value in pregnancy increases the risk for future diabetes mellitus type 2

PURPOSE

Women with only one elevated 100 g OGTT value are not considered as having gestational diabetes mellitus (GDM) and therefore there are no recommendations to address this population as a risk group for type 2 diabetes mellitus (T2DM). We aimed to elucidate whether one elevated OGTT value increases the risk for T2DM.

METHODS

A retrospective population-based cohort study of women with a first diagnosis of GDM who delivered between 1991 and 2011 was conducted. Women were divided according to GDM diagnosis criteria into three groups: (1) at least two elevated values of Carpenter and Coustan criteria (C&C; N = 209), (2) At least two elevated values of the National Diabetes Data Group (NDDG) criteria (NDDG2; N = 290) and (3) only one elevated value of the NDDG criteria (NDDG1; N = 226). A fourth group comprising women without GDM was included (control; N = 352). The primary outcome was the development of T2DM.

RESULTS

The mean follow-up was 12.4 ± 5.3 years and the mean age at follow-up was 43.0 ± 5.7 years. The rate of T2DM in the control, C&C, NDDG1 and NDDG2 groups were 5%, 18%, 19% and 31%, respectively. All GDM diagnoses were independent risk factors for T2DM in multivariable Cox regression when compared to controls, adjusted hazard ratio and 95% CI: C&C 7.8 [95% CI 3.7-16.4], NDDG1 5.5 [2.6-11.6], and NDDG2 10.5 [5.2-21.4]. Additional independent risk factors were parity, fasting and 1-h post-glucose load of the OGTT and insulin use.

CONCLUSIONS

Women with one elevated OGTT value using the NDDG criteria are at increased risk for T2DM. Further studies are needed to decide whether those women should be considered a focus group for long-term surveillance and T2DM prevention interventions.

Young-onset type 2 diabetes mellitus - implications for morbidity and mortality

Accumulating data suggest that type 2 diabetes mellitus (T2DM) in younger people (aged <40 years), referred to as young-onset T2DM, has a more rapid deterioration of β-cell function than is seen in later-onset T2DM. Furthermore, individuals with young-onset T2DM seem to have a higher risk of complications than those with type 1 diabetes mellitus. As the number of younger adults with T2DM increases, young-onset T2DM is predicted to become a more frequent feature of the broader diabetes mellitus population in both developing and developed nations, particularly in certain ethnicities. However, the magnitude of excess risk of premature death and incident complications remains incompletely understood; likewise, the potential reasons for this excess risk are unclear. Here, we review the evidence pertaining to young-onset T2DM and its current and future burden of disease in terms of incidence and prevalence in both developed and developing nations. In addition, we highlight the associations of young-onset T2DM with premature mortality and morbidity.

The changing face of paediatric diabetes

The purpose of this review is to provide an update on the changing face of paediatric type 1 diabetes and type 2 diabetes. Paediatric diabetes is on the rise, with extensive research dedicated to understanding its pathophysiology, comorbidities and complications. As obesity continues to increase among all youth, differentiating between type 1 diabetes and type 2 diabetes has become increasingly difficult but remains important for optimising treatment, anticipating complications and predicting disease risk. Novel treatments are emerging, with the ultimate goal being to achieve glycaemic control, limit weight gain, improve quality of life and reduce comorbidities. In this review, we focus on updates regarding the epidemiology, clinical presentation, comorbidities and complications of paediatric type 1 diabetes and type 2 diabetes and conclude with current and emerging treatments.

Nonalcoholic fatty liver disease in obese adolescent females is associated with multi-tissue insulin resistance and visceral adiposity markers

Objective

Nonalcoholic fatty liver disease (NAFLD) is associated with insulin resistance (IR) and visceral adiposity in adults and boys, but girls with NAFLD are understudied. We sought to evaluate adipose, liver, and skeletal muscle insulin sensitivity in obese adolescent females with or without hepatic steatosis (HS) (intrahepatic triglyceride (IHTG) content >5.5%) along with cardiometabolic components typically associated with IR.

Study design

73 obese adolescent girls at high risk for NAFLD were enrolled. Participants underwent fasting labs, an MRI to measure IHTG and visceral fat, ³¹phosphorous MR spectroscopy for muscle mitochondrial function, ¹H MR spectroscopy for intramyocellular lipid (IMCL), bicycle ergometry to assess VO₂peak and a 4-phase hyperinsulinemic euglycemic clamp with isotope tracers to measure hepatic and peripheral IR. 29 participants had HS [age 15 yrs(13,16), BMI%ile 98.7(97.4,99.0), IHTG 10.4%(8.0,13.5)] and 44 did not [age 15 yrs(13,17), BMI%ile 98.5(96.2,99.0), IHTG 2.0%(1.1,3.0)].

Results

During hyperinsulinemia, participants with HS vs. non-HS had failure to suppress free fatty acids (p = 0.008), endogenous glucose release (p = 0.002), and a lower glucose metabolic rate of disappearance (Rd) (p = 0.012). Girls with NALFD also had higher visceral fat (p < 0.001), systolic blood pressure (p = 0.026), triglycerides (p = 0.02), ALT (p < 0.01) and white blood cell count (p < 0.01), and lower adiponectin (p = 0.02). There was no difference between girls with and without HS in systemic glycerol turnover measured with glycerol release, or in IMCL, mitochondrial function or VO₂peak.

Conclusions

Obese adolescent girls with HS have evidence of multi-tissue IR, visceral adiposity, inflammation and multiple components of the metabolic syndrome, arguing for close cardiometabolic surveillance over time of girls with HS.

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We described tissue specific insulin sensitivity in adolescent girls ± NAFLD.

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Girls with NAFLD have higher hepatic and muscular insulin resistance.

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Intramyocellular lipids and muscle mitochondrial function were not different between groups.

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Adipose tissue insulin resistance was not different between groups.

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Girls with NAFLD have worst metabolic profile than those without.

Youth with type 2 diabetes have hepatic, peripheral, and adipose insulin resistance

Adolescents with type 2 diabetes (T2D) have severe insulin resistance (IR) secondary to obesity, genetics, and puberty, and IR predicts metabolic comorbidities. Adults with T2D have multitissue IR, which has guided therapeutic developments, but this is not established in youth. We sought to assess adipose, hepatic, and peripheral insulin sensitivity in adolescents with and without T2D. Twenty-seven youth with T2D [age: 15.6 ± 0.4 yr; female: 78%; body mass index (BMI) percentile: 96.1 (52.6, 95.9), late puberty; hemoglobin A1c (HbA1c) 7.3% (6.2, 10.1)] and 21 controls of similar BMI, pubertal stage, and habitual activity were enrolled. Insulin action was measured with a four-phase hyperinsulinemic-euglycemic clamp (basal, 10, 16, and 80 mU·m^-2·min^-1 for studying adipose, hepatic, and peripheral IR, respectively) with glucose and glycerol isotope tracers. Total fat mass, fat-free mass, liver fat fraction, and visceral fat were measured with dual-energy x-ray absorptiometry (DXA) and MRI, respectively. Free fatty acids (FFAs), lipid profile, and inflammatory markers were also measured. Adolescents with T2D had higher lipolysis ( P = 0.012), endogenous glucose production ( P < 0.0001), and lower glucose clearance ( P = 0.002) during hyperinsulinemia than controls. In T2D, peripheral IR positively correlated to FFA ( P < 0.001), inflammatory markers, visceral ( P = 0.004) and hepatic fat ( P = 0.007); hepatic IR correlated with central obesity ( P = 0.004) and adipose IR ( P = 0.003). Youth with T2D have profound multitissue IR compared with BMI-equivalent youth without T2D. The development of multitissue interactions appears crucial to the pathogenesis of T2D. Therapeutic targets on multitissue IR may be of benefit, deserving of further research.

Using simple clinical measures to predict insulin resistance or hyperglycemia in girls with polycystic ovarian syndrome

BACKGROUND

Polycystic ovarian syndrome (PCOS) includes insulin resistance (IR) and impaired glucose tolerance (IGT) in youth, and a greatly elevated risk of type 2 diabetes in adulthood. Identifying IR is challenging and documenting IGT requires an oral glucose tolerance test (OGTT).

OBJECTIVE

Identify easily applied surrogate measures for IR and IGT in girls with PCOS.

METHODS

We studied 28 girls with PCOS (body mass index [BMI] percentile 98 (83.99); 15.5 (14.5,16.6) years of age) and 20 with normal menses [BMI percentile (97 (88.99); 15.5 (13.3,16.1) years]. Hyperinsulinemic-euglycemic clamps (insulin dose of 80 μU/ml/min) to determine glucose infusion rate (GIR) and a 75 g OGTT were performed. Surrogates for IR including fasting insulin, homeostatic model assessment-insulin resistant (HOMA-IR), Matsuda index, and estimate of insulin sensitivity (e-IS) were compared to IGT status and GIR. Spearman correlations were performed between surrogates and GIR or IGT, and receiver operator curve (ROC) analysis to predict GIR below the median or IGT status.

RESULTS

GIR was lower in PCOS (12.9 ± 4.6 vs 17.1 ± 5.1 mg/kg fat-free mass·min; P = 0.01). Within PCOS, HOMA-IR (r = -0.78, P < 0.0001), e-IS (r = 0.70, P < 0.001), and Matsuda (r = 0.533, P < 0.001) correlated with GIR. e-IS provided a good sensitivity (100%) and specificity (71%) to identify IR (e-IS cutoff: <6.3, ROC-area under curve = 0.898). Fasting insulin >22 IU/mL had the best sensitivity (88%), specificity (78%), and ROC (0.760) for IGT status.

CONCLUSIONS

Girls with PCOS have significant IR, and IGT is common. Both e-IS and fasting insulin are obtainable without an OGTT or clamp and could be used clinically to guide treatment in PCOS.

Youth With Type 1 Diabetes Have Adipose, Hepatic, and Peripheral Insulin Resistance

CONTEXT

Adolescents with type 1 diabetes (T1D) have difficulty obtaining optimal glucose control, which may relate to insulin resistance (IR), especially during puberty. Moreover, IR increases the risk for cardiovascular disease, the leading cause of death in T1D. However, the tissue specificity of IR in adolescents with T1D has not been fully phenotyped.

OBJECTIVE

To assess adipose, hepatic, and peripheral insulin sensitivity in adolescents with and without T1D.

DESIGN AND SETTING

Thirty-five youth with T1D [median age, 16 (first and third quartiles, 14, 17) years; 53% female; median body mass index (BMI) percentile, 82nd (55th, 96th); late puberty; median hemoglobin A1c, 8.3% (7.3%, 9.4%)] and 22 nondiabetic youth of similar age, BMI, pubertal stage, and level of habitual physical activity were enrolled. Insulin action was measured with a four-phase hyperinsulinemic euglycemic clamp (basal and 10, 16, and 80 mU/m2/min) with glucose and glycerol isotope tracers.

RESULTS

Adolescents with T1D had a significantly higher rate of lipolysis (P < 0.0001) and endogenous glucose production (P < 0.001) and lower peripheral glucose uptake (glucose rate of disappearance, 6.9 ± 2.9 mg/kg/min for patients with T1D vs 11.3 ± 3.3 for controls; P < 0.0001) during hyperinsulinemia compared with controls. In youth with T1D, glucose rate of disappearance correlated with free fatty acid at the 80-mU/m2/min phase (P = 0.005), markers of inflammation (IL-6; P = 0.012), high-sensitivity C-reactive protein (P = 0.001), and leptin (P = 0.008)], but not hemoglobin A1c.

CONCLUSIONS

Adolescents with T1D have adipose, hepatic and peripheral IR. This IR occurs regardless of obesity and metabolic syndrome features. Youth with T1D may benefit from interventions directed at improving IR in these tissues, and this area requires further research.

Oral Glucose Tolerance Test Glucose Peak Time Is Most Predictive of Prediabetes and Hepatic Steatosis in Obese Girls

Obese adolescent girls are at increased risk for type 2 diabetes, characterized by defects in insulin secretion and action. We sought to determine if later glucose peak timing (>30 minutes), 1-hour glucose >155 mg/dl, or monophasic pattern of glucose excursion during an oral glucose tolerance test (OGTT) reflect a worse cardiometabolic risk profile. Post-pubertal overweight/obese adolescent girls without diabetes were studied (N = 88; age, 15.2 ± 0.2 years; body mass index percentile, 97.7 ± 0.5). All participants completed an OGTT and body composition measures. Thirty-two girls had a four-phase hyperinsulinemic euglycemic clamp with isotope tracers, vascular imaging, and muscle mitochondrial assessments. Participants were categorized by glucose peak timing (≤30 min = early; >30 min = late), 1-hour glucose concentration (±155 mg/dL) and glucose pattern (monophasic, biphasic). Girls with a late (N = 54) vs earlier peak (n = 34) timing had higher peak glucose (P < 0.001) and insulin (P = 0.023), HbA1c (P = 0.021); prevalence of hepatic steatosis (62% vs 26%; P = 0.003) and lower oral disposition index (P < 0.001) and glucagon-like peptide-1 response (P = 0.037). When classified by 1-hour glucose, group differences were similar to peak timing, but minimal when classified by glucose pattern. In the >155 mg/dL group only, peripheral insulin sensitivity and fasting free fatty acids were worse. A later glucose peak or >155 mg/dL 1-hour glucose predicts metabolic disease risk in obese adolescent girls. This may defect incretin effects and first phase insulin response, and muscle and adipose insulin resistance.

Oral Glucose Tolerance Test Glucose Peak Time Is Most Predictive of Prediabetes and Hepatic Steatosis in Obese Girls

Obese adolescent girls are at increased risk for type 2 diabetes, characterized by defects in insulin secretion and action. We sought to determine if later glucose peak timing (>30 minutes), 1-hour glucose >155 mg/dl, or monophasic pattern of glucose excursion during an oral glucose tolerance test (OGTT) reflect a worse cardiometabolic risk profile. Post-pubertal overweight/obese adolescent girls without diabetes were studied (N = 88; age, 15.2 ± 0.2 years; body mass index percentile, 97.7 ± 0.5). All participants completed an OGTT and body composition measures. Thirty-two girls had a four-phase hyperinsulinemic euglycemic clamp with isotope tracers, vascular imaging, and muscle mitochondrial assessments. Participants were categorized by glucose peak timing (≤30 min = early; >30 min = late), 1-hour glucose concentration (±155 mg/dL) and glucose pattern (monophasic, biphasic). Girls with a late (N = 54) vs earlier peak (n = 34) timing had higher peak glucose (P < 0.001) and insulin (P = 0.023), HbA1c (P = 0.021); prevalence of hepatic steatosis (62% vs 26%; P = 0.003) and lower oral disposition index (P < 0.001) and glucagon-like peptide-1 response (P = 0.037). When classified by 1-hour glucose, group differences were similar to peak timing, but minimal when classified by glucose pattern. In the >155 mg/dL group only, peripheral insulin sensitivity and fasting free fatty acids were worse. A later glucose peak or >155 mg/dL 1-hour glucose predicts metabolic disease risk in obese adolescent girls. This may defect incretin effects and first phase insulin response, and muscle and adipose insulin resistance.

Type 2 diabetes in adolescents and young adults

The prevalence of type 2 diabetes in adolescents and young adults is dramatically increasing. Similar to older-onset type 2 diabetes, the major predisposing risk factors are obesity, family history, and sedentary lifestyle. Onset of diabetes at a younger age (defined here as up to age 40 years) is associated with longer disease exposure and increased risk for chronic complications. Young-onset type 2 diabetes also affects more individuals of working age, accentuating the adverse societal effects of the disease. Furthermore, evidence is accumulating that young-onset type 2 diabetes has a more aggressive disease phenotype, leading to premature development of complications, with adverse effects on quality of life and unfavourable effects on long-term outcomes, raising the possibility of a future public health catastrophe. In this Review, we describe the epidemiology and existing knowledge regarding pathophysiology, risk factors, complications, and management of type 2 diabetes in adolescents and young adults.

Identification of key gene pathways and coexpression networks of islets in human type 2 diabetes

PURPOSE

The number of people with type 2 diabetes (T2D) is growing rapidly worldwide. Islet β-cell dysfunction and failure are the main causes of T2D pathological processes. The aim of this study was to elucidate the underlying pathways and coexpression networks in T2D islets.

MATERIALS AND METHODS

We analyzed the differentially expressed genes (DEGs) in the data set GSE41762, which contained 57 nondiabetic and 20 diabetic samples, and developed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Protein-protein interaction (PPI) network, the modules from the PPI network, and the gene annotation enrichment of modules were analyzed as well. Moreover, a weighted correlation network analysis (WGCNA) was applied to screen critical gene modules and coexpression networks and explore the biological significance.

RESULTS

We filtered 957 DEGs in T2D islets. Then GO and KEGG analyses identified that key pathways like inflammatory response, type B pancreatic cell differentiation, and calcium ion-dependent exocytosis were involved in human T2D. Three significant modules were filtered from the PPI network. Ribosome biogenesis, extrinsic apoptotic signaling pathway, and membrane depolarization during action potential were associated with the modules, respectively. Furthermore, coexpression network analysis by WGCNA identified 13 distinct gene modules of T2D islets and revealed four modules, which were strongly correlated with T2D and T2D biomarker hemoglobin A1c (HbA1c). Functional annotation showed that these modules mainly enriched KEGG pathways such as NF-kappa B signaling pathway, tumor necrosis factor signaling pathway, cyclic adenosine monophosphate signaling pathway, and peroxisome proliferators-activated receptor signaling pathway.

CONCLUSION

The results provide potential gene pathways and underlying molecular mechanisms for the prevention, diagnosis, and treatment of T2D.

Higher parity is associated with increased risk of Type 2 diabetes mellitus in women: A linear dose-response meta-analysis of cohort studies

AIM

The goal of this study is to investigate the association between higher parity and the risk of occurrence of type 2 diabetes mellitus (T2DM) in women and to quantify the potential dose-response relation.

METHODS

We searched MEDLINE, and EMBASE electronic databases for related cohort studies up to March 10th, 2016. Summary rate ratios (RRs) and 95% confidence intervals (CIs) for T2DM with at least 3 categories of exposure were eligible. A random-effects dose-response analysis procedure was used to study the relations between them.

RESULTS

After screening a total of 13,647 published studies, only 7 cohort studies (9,394 incident cases and 286,840 female participants) were found to be eligible for this meta-analysis. In the category analysis, the pooled RR for the highest number of parity vs. the lowest one was 1.42 (95% CI: 1.17-1.72, I²=71.5%, P_{heterogeneity}=0.002, Power=0.99). In the dose-response analysis, a noticeable linear dose-risk relation was found between parity and T2DM (P_{for nonlinearity test}=0.942). For every live birth increase in parity, the combined RR was 1.06 (95% CI: 1.02-1.09, I²=84.3%, P_{heterogeneity}=0.003, Power=0.99). Subgroup and sensitivity analyses yielded similar results. No publication bias was found in the results.

CONCLUSION

This meta-analysis suggests that higher parity and the risk of T2DM show a linear relationship in women.

Hepatic Steatosis is Common in Adolescents with Obesity and PCOS and Relates to De Novo Lipogenesis but not Insulin Resistance

OBJECTIVE

Increased liver fat and type 2 diabetes are prevalent in women with polycystic ovarian syndrome (PCOS) and cause excess mortality, yet little is known about their development during adolescence. The objective of this study was to measure hepatic steatosis and related metabolic contributors in girls with obesity, with and without PCOS.

METHODS

Nondiabetic adolescents with obesity, 41 with PCOS (PCOS; age 15.0 [13.0-16.0] years, BMI 35.2 ± 0.61 kg/m2 ) and 30 without PCOS (OB; age 14.5 [13.0-17.0], BMI 33.2 ± 1.8), were studied. Visceral and liver fat were assessed with MRI. Serum measures included androgens and 16:1 and 18:1 N7 fatty acids specific to de novo lipogenesis. Adipose, hepatic, and peripheral insulin sensitivity (IS) were assessed with a four-phase hyperinsulinemic-euglycemic clamp with isotope tracers.

RESULTS

Forty-nine percent of the PCOS group had hepatic steatosis versus fourteen percent of the OB group (P = 0.02), and the PCOS group had higher N7 (43 ± 4 vs. 29 ± 5 nmol/g; P = 0.02). Peripheral IS was lower in PCOS (9.4 [7.2-12.3] vs. 14.5 [13.1-18.05 mg/lean kg/min]; P < 0.001) as was hepatic (P = 0.006) and adipose IS (P = 0.005). Percent liver fat correlated with N7 (R = 0.46, P = 0.02) and visceral fat (R = 0.42, P < 0.001), not androgens or peripheral IS.

CONCLUSIONS

Nearly 50% of nondiabetic girls with PCOS and obesity have hepatic steatosis, which relates to visceral fat and lipogenesis, but not to IS or androgens.

Modeling changes in glucose and glycerol rates of appearance when true basal rates of appearance cannot be readily determined

Advancing diabetes care requires accurate physiological assessments. Hyperinsulinemic clamps with stable isotope tracers can simultaneously measure insulin's ability to suppress lipolysis and hepatic glucose release. Traditionally, these methods require an assessment of basal glucose and glycerol rate of appearance (Ra). Basal Ra is challenging to measure in insulin-dependent diabetes, where exogenous insulin required to maintain normoglycemia can raise peripheral insulin concentrations sufficiently to suppress basal Ra. Thus we identified two alternative statistical approaches to describe changes in glucose and glycerol Ra that are less reliant on basal assessments. Sixteen youths (4 type 1 diabetic, 4 type 2 diabetic, 4 lean controls, and 4 obese nondiabetic) underwent a four-phase ("basal" and 10, 16, and 80 mU·m(2)·min(-1)) hyperinsulinemic euglycemic clamp with glucose and glycerol tracers. Glucose and glycerol Ra were calculated per phase. A statistical method, the standard two-stage (STS) algorithm, was applied to the individual log insulin vs. Ra curves to calculate a single predicted Ra value. A population-based mixed-effects model (MEM) compared the group average Ra with log insulin curves and described individual deviations from group means and was used to calculate individual predicted Ra. Both models were applied to the participant data, and predicted Ras at the mean insulin concentration per phase (10 for glycerol, 16 for glucose) were calculated, with good agreement between observed and predicted values. In our data set, the MEM was better able to detect group differences. Both STS and MEM can model lipolysis and endogenous glucose release in insulin-dependent states when basal Ra cannot be accurately measured.

The changing face of diabetes in youth: lessons learned from studies of type 2 diabetes

The incidence of youth type 2 diabetes (T2D), linked with obesity and declining physical activity in high-risk populations, is increasing. Recent multicenter studies have led to a number of advances in our understanding of the epidemiology, pathophysiology, diagnosis, treatment, and complications of this disease. As in adult T2D, youth T2D is associated with insulin resistance, together with progressive deterioration in β cell function and relative insulin deficiency in the absence of diabetes-related immune markers. In contrast to adult T2D, the decline in β cell function in youth T2D is three- to fourfold faster, and therapeutic failure rates are significantly higher in youth than in adults. Whether the more aggressive nature of youth T2D is driven by genetic heterogeneity or physiology/metabolic maladaptation is yet unknown. Besides metformin, the lack of approved pharmacotherapeutic agents for youth T2D that target the pathophysiological mechanisms is a major barrier to optimal diabetes management. There is a significant need for effective therapeutic options, in addition to increased prevention, to halt the projected fourfold increase in youth T2D by 2050 and the consequences of heightened diabetes-related morbidity and mortality at younger ages.

Diabetes mellitus: The epidemic of the century

The epidemic nature of diabetes mellitus in different regions is reviewed. The Middle East and North Africa region has the highest prevalence of diabetes in adults (10.9%) whereas, the Western Pacific region has the highest number of adults diagnosed with diabetes and has countries with the highest prevalence of diabetes (37.5%). Different classes of diabetes mellitus, type 1, type 2, gestational diabetes and other types of diabetes mellitus are compared in terms of diagnostic criteria, etiology and genetics. The molecular genetics of diabetes received extensive attention in recent years by many prominent investigators and research groups in the biomedical field. A large array of mutations and single nucleotide polymorphisms in genes that play a role in the various steps and pathways involved in glucose metabolism and the development, control and function of pancreatic cells at various levels are reviewed. The major advances in the molecular understanding of diabetes in relation to the different types of diabetes in comparison to the previous understanding in this field are briefly reviewed here. Despite the accumulation of extensive data at the molecular and cellular levels, the mechanism of diabetes development and complications are still not fully understood. Definitely, more extensive research is needed in this field that will eventually reflect on the ultimate objective to improve diagnoses, therapy and minimize the chance of chronic complications development.

HLA-typing, clinical, and immunological characterization of youth with type 2 diabetes mellitus phenotype from the German/Austrian DPV database

AIM

To characterize the clinical and immunological features of HLA-typed youth with pediatric onset of type 2 diabetes mellitus (T2DM).

METHOD

One hundred and seven patients with clinically diagnosed T2DM (aged ≤20 yr at diagnosis) were examined. DNA and serum, obtained after a median diabetes duration of 2.2 (Q1-Q3: 0.8-4.6) yr, were used for centralized HLA-typing and autoantibody (GADA, IA-2A, ZnT8A) measurements.

RESULTS

64.6% of patients were female and median age at diagnosis was 13.8 (Q1-Q3: 11.6-15.4) yr. Patients were obese [median body mass index-standard deviation score (BMI-SDS): 2.6 (2.0-3.1)], 88.0% had a family history of diabetes and 40.2% a migration background. Islet autoantibodies were detected in 16 (15.0%), among which 7 (6.5%) had multiple islet autoantibodies. Autoantibody positive patients had poorer metabolic control than autoantibody negative patients [glycosylated hemoglobin A1c (HbA1c): 8.1 (6.9-10.1) % vs. 6.6 (5.9-8.0) %; p = 0.033], while patients with HLA-DR genetic risk had higher BMI-SDS than those with HLA-DRXX [2.6 (2.4-3.7) vs. 2.4 (1.7-2.9); p = 0.007]. Metabolic syndrome (61.7%), microalbuminuria (13.4%), and retinopathy (3.9%) were diagnosed. Therapies used were lifestyle only (35.5%), oral anti-diabetics (OAD) only (43.3 %), insulin +  OAD (15.9%) and insulin only (5.6%). Patients with β-cell autoimmunity or HLA-DR genetic risk more frequently used insulin than confirmed T2DM patients (50.0 vs. 22.0%; p = 0.037) and less often had diabetic relatives (61.1 vs. 86.0%; p = 0.030).

CONCLUSION

T2DM was confirmed in about 90% of patients while about 10% with β-cell autoimmunity or HLA-DR genetic risk likely had either T1.5DM or 'double diabetes' or an unknown diabetes type.

Characterization of β-cell function and insulin resistance in overweight Chinese adolescents with normal glucose tolerance

This study aimed to investigate the characteristics of insulin resistance and β-cell secretion in healthy adolescents. A total of 124 adolescents with normal glucose tolerance (NGT) were divided according to BMI into normal weight (n=31; control), overweight (n=52) and obese (n=41) groups. Oral glucose tolerance tests were performed, and blood glucose (G₀, G₃₀ and G₁₂₀) and insulin (I₀, I₃₀ and I₁₂₀) levels at 0, 30 and 120 min, respectively, were measured. The homeostasis model assessment estimate of insulin resistance (HOMA-IR) and early insulin release index (IRI) were calculated to evaluate insulin sensitivity and early β-cell secretion. The G₀, G₁₂₀ levels and the natural logarithm (Ln) of I₃₀ and ΔI₃₀/ΔG₃₀ were similar in the overweight and obese groups, but significantly higher compared with those of the normal weight group (P<0.05). LnI₀ and LnHOMA-IR progressively increased (P<0.01) in correlation with the degree of obesity among the three groups. LnΔI₃₀/ΔG₃₀ and LnHOMA-IR were significantly positively correlated with the indices of obesity (P<0.001 and P<0.05, respectively). LnHOMA-IR was also positively correlated with the insulin levels at 30 and 120 min (r=0.454 and 0.314, respectively; P<0.001). In healthy adolescents, insulin resistance progressively increased with increased body mass index (BMI), but the compensatory increase in early insulin secretion was limited.

Aldosterone excess impairs first phase insulin secretion in primary aldosteronism

CONTEXT

Primary aldosteronism (PA) represents the most frequent cause of secondary arterial hypertension. Conflicting data have been published regarding the effect of aldosterone excess on glucose metabolism.

OBJECTIVE

Our aim was to analyze insulin sensitivity and β-cell function in a cohort of PA patients. Prospective follow-up investigations were performed in a subgroup of patients before and after adrenalectomy to assess the metabolic outcome.

DESIGN

Oral glucose tolerance test, combined intravenous glucose tolerance test, hyperinsulinemic-euglycemic glucose clamp test, and arginine test were carried out after a 12-hour fasting period.

PATIENTS

Twenty-two consecutive patients with both unilateral aldosterone-producing adenoma and bilateral idiopathic adrenal hyperplasia were recruited through the Munich center of the German Conn's Registry. The control group of patients with essential hypertension (n = 11) of corresponding age and body mass index was recruited from our hypertension unit. A normotensive cohort (n = 11) served as a further control group.

RESULTS

At baseline, first-phase insulin reaction in intravenous glucose tolerance test was significantly reduced in patients with PA as compared to normal controls (36.0 [24.0; 58.7] vs 90.1 [52.6; 143.8] μU/mL, P = .031) and lower in comparison to essential hypertension without reaching statistical significance (53.2 [30.8; 73.3] μU/mL, P = .123). The study was repeated 6 months after unilateral adrenalectomy in 9 consecutive patients with aldosterone-producing adenoma. At this time point, blood pressure had been normalized in most of the patients while body mass index remained unchanged (26.9 [25.5; 37.6] vs 27.5 [25.1; 35.6] kg/m(2), P = .401). First-phase insulin reaction in response to glucose significantly increased at follow-up (from 36.0 [25.5; 58.7] to 48.5 [40.4; 95.2] μU/mL, P = .038, n = 9). In contrast, insulin sensitivity and response to iv arginine did not differ before and after adrenalectomy.

CONCLUSION

Aldosterone excess has a direct negative effect on β-cell function in patients with PA. After adrenalectomy, glucose-induced first-phase insulin secretion improves significantly in the patients.

Progressive deterioration of β-cell function in obese youth with type 2 diabetes

OBJECTIVE

In adults, type 2 diabetes (T2DM) is characterized with progressive deterioration in insulin secretion. Data are scanty in youth. We investigated prospectively the change in β-cell function and in insulin sensitivity in youth with T2DM.

RESEARCH DESIGN AND METHODS

Six adolescents with T2DM [hemoglobin A1c (HbA1c) 6.6 ± 1.0%] underwent evaluation of hepatic glucose production (HGP; [6,6-²H₂] glucose), insulin-stimulated glucose disposal (Rd; hyperinsulinemic-euglycemic clamp), first- and second-phase insulin/C-peptide secretion (hyperglycemic clamp), body composition dual energy X-ray absorptiometry (DEXA), and abdominal adiposity (computed tomography) within 3 yr of the diagnosis of diabetes and after 12-16 months of follow-up.

RESULTS

Weight, body mass index (37.1 ± 6.9), HbA1c (6.3 ± 0.7%), HGP (2.8 ± 1.2 mg/kg/min), and Rd (4.9 ± 3.4 mg/kg/min) did not change significantly from baseline. However, first-phase insulin and C-peptide declined (152.6 ± 261.2 vs. 75.9 ± 108.5 μU/mL, p = 0.028; 8.0 ± 6.3 vs. 5.9 ± 4.4 ng/mL, p = 0.048, respectively) with no significant change in second-phase insulin/C-peptide. The rate of decline in β-cell function was ∼20% per year.

CONCLUSIONS

After a median duration of 20 months of diabetes, youth with T2DM manifest a rapid decline in β-cell function with no significant changes in peripheral or hepatic insulin sensitivity. Interventions to retard this deterioration in β-cell function should be investigated.

The influence of exposure to maternal diabetes in utero on the rate of decline in β-cell function among youth with diabetes

Abstract We explored the influence of exposure to maternal diabetes in utero on β cell decline measured by fasting C-peptide (FCP) among 1079 youth <20 years with diabetes, including 941 with type 1 and 138 with type 2 diabetes. Youths exposed to maternal diabetes had FCP levels that were 17% lower among youth with type 2 diabetes [95% confidence interval (CI): -34%, +6%] and 15% higher among youth with type 1 diabetes (95%CI: -14%, +55%) than their unexposed counterparts, although differences were not statistically significant (p=0.13 and p=0.35, respectively). Exposure to maternal diabetes was not associated with FCP decline in youth with type 2 (p=0.16) or type 1 diabetes (p=0.90); nor was the effect of in utero exposure on FCP modified by diabetes type. Findings suggest that exposure to maternal diabetes in utero may not be an important determinant of short-term β-cell function decline in youth with type 1 or type 2 diabetes.

Clinical evolution of beta cell function in youth with diabetes: the SEARCH for Diabetes in Youth study

AIMS/HYPOTHESIS

Few studies have explored the epidemiology of beta cell loss in youth with diabetes. This report describes the evolution and major determinants of beta cell function, assessed by fasting C-peptide (FCP), in the SEARCH for Diabetes in Youth study.

METHODS

Participants were 1,277 youth with diabetes (948 positive for diabetes autoantibodies [DAs] and 329 negative for DAs), diagnosed when aged <20 years, who were followed from a median of 8 months post diagnosis, for approximately 30 months. We modelled the relationship between rate of change in log FCP and determinants of interest using repeated measures general linear models.

RESULTS

Among DA-positive youth, there was a progressive decline in beta cell function of 4% per month, independent of demographics (age, sex, race/ethnicity), genetic susceptibility to autoimmunity (HLA risk), HbA(1c) and BMI z score, or presence of insulin resistance. Among DA-negative youth, there was marked heterogeneity in beta cell loss, reflecting an aetiologically mixed group. This group likely includes youths with undetected autoimmunity (whose decline is similar to that of DA-positive youth) and youth with non-autoimmune, insulin-resistant diabetes, with limited decline (~0.7% per month).

CONCLUSIONS/INTERPRETATION

SEARCH provides unique estimates of beta cell function decline in a large sample of youth with diabetes, indicating that autoimmunity is the major contributor. These data contribute to a better understanding of clinical evolution of beta cell function in youth with diabetes, provide strong support for the aetiological classification of diabetes type and may inform tertiary prevention efforts targeted at high-risk groups.

The incidence, clinical features, and treatment of type 2 diabetes in children <15 yr in a population-based cohort from Auckland, New Zealand, 1995–2007

BACKGROUND

The incidence of type 2 diabetes mellitus (T2DM) is increasing in adolescents in most western countries. The time-course of glycemic control and impact of early treatment remain poorly understood.

OBJECTIVES

To determine the change in incidence of T2DM, and the time-course of glycemic control in a regional pediatric cohort with T2DM.

METHODS

Retrospective analysis of prospectively collected data on 52 patients with T2DM from a population-based treatment referral cohort from 1 January 1995 to 31 December 2007.

RESULTS

The annual incidence of new cases of T2DM in children <15 yr increased fivefold in the Auckland region of New Zealand from 1995 [0.5/100,000; 95% confidence interval (CI) 0.0–2.2] to 2007 (2.5/100,000; 95% CI 1.0–5.5). The average annual incidence per 100,000 over the entire period was 1.3 (95% CI 1.0–1.8) overall, 0.1 (0.0–0.4) in Europeans, and 3.4 in both Maori (2.0–5.3) and Pacifica (2.2–5.0). Fifty-seven percent of children were symptomatic at presentation. Fifty-eight percent of patients were treated with insulin from diagnosis, most of whom were symptomatic (p = 0.003). Follow-up data were available for 48 patients with a mean of 2.4 yr. Although insulin therapy was associated with a greater fall in HbA1c values in the first 12 months of treatment (to a nadir of 7.1 vs. 8.1%, p < 0.05), there was a rapid deterioration after 12 months, and subsequent mean HbA1c values were >9% in both groups. Therapy did not affect body mass index standard deviation score (BMI SDS).

CONCLUSIONS

The incidence of T2DM in childhood or adolescence increased markedly over a 13-yr period in the Auckland region. Long-

Glycemic control in youth with type 2 diabetes declines as early as two years after diagnosis

OBJECTIVES

To determine the course of glycemic decline in a pediatric cohort with type 2 diabetes mellitus (T2DM) by defining longitudinal changes in hemoglobin A1c (HbA1c) and insulin requirement. We also followed markers of insulin reserve (fasting C-peptide and IGFBP-1) over time.

STUDY DESIGN

Participants included two groups: (1) T2DM Nonacidotic (NA) (n = 46); and (2) T2DM diabetic ketoacidosis (n = 13). HbA1c, insulin dose, and fasting C-peptide and IGFBP-1 were obtained at baseline and every 6 months for 4 years.

RESULTS

At baseline, Mann Whitney tests demonstrated that the diabetic ketoacidosis group had higher HbA1c (P = .002), required more insulin (P = .036), and had lower C-peptide (P = .003) than the NA group. Baseline insulin dose (Spearman r = -0.424, P = .009) and baseline IGFBP-1 (Spearman r = -0.349, P = .046) correlated negatively with C-peptide. Over time, HbA1c, insulin dose, and C-peptide changed significantly in a complex manner, with group differences. HbA1c reached a nadir at 6 to 12 months and began to rise after 1.5 years. Insulin requirements reached a nadir at 1 year and began to rise after 2 years.

CONCLUSIONS

Unlike adults, children with T2DM require increasing insulin doses over a 4-year period, and diabetic ketoacidosis at diagnosis predicts greater β-cell decline over time.

Remission of diabetes mellitus in cats cannot be predicted by the arginine stimulation test

BACKGROUND

Cats with diabetes mellitus frequently achieve clinical remission, suggesting residual β-cell function. Responsiveness of β-cells to arginine persists the longest during diabetes progression, making the intravenous arginine stimulation test (IVAST) a useful tool to assess residual insulin and glucagon secretion.

HYPOTHESIS

Diabetic cats with and without remission will have different arginine-induced insulin or glucagon response.

ANIMALS

Seventeen cats with diabetes, 7 healthy cats.

METHODS

Blood samples collected on admission and during subsequent IVAST. Glucose, insulin, and glucagon were measured. Response to IVAST was assessed by calculating the insulin and glucagon area under the curve (AUC) and the AUC glucagon-to-insulin ratio. Diabetic cats were treated with insulin and were followed for 18 weeks. Remission was defined as normoglycemia and disappearance of clinical signs of diabetes for ≥4 weeks, without requiring insulin.

RESULTS

Seven diabetic cats (41%) achieved remission. On admission, blood glucose concentration was significantly lower in cats with remission (median, 389 mg/dL; range, 342-536 mg/dL) than in those without remission (median, 506 mg/dL; range, 266-738 mg/dL). After IVAST, diabetic cats with remission had higher AUC glucagon-to-insulin ratios (median, 61; range, 34-852) than did cats without remission (median, 26; range, 20-498); glucose, insulin, and glucagon AUCs were not different. Diabetic cats had lower insulin AUC than did healthy cats but comparable glucagon AUC.

CONCLUSIONS AND CLINICAL IMPORTANCE

Diabetic cats with and without remission have similar arginine-stimulated insulin secretion on admission. Although cats with remission had lower blood glucose concentrations and higher AUC glucagon-to-insulin ratios, large overlap between groups prevents use of these parameters in clinical practice.

Impaired beta-cell sensitivity to glucose and maximal insulin secretory capacity in adolescents with type 2 diabetes

BACKGROUND

Adults with type 2 diabetes mellitus (T2DM) have broad impairments in beta-cell function, including severe attenuation of the first-phase insulin response to glucose, and reduced beta-cell mass. In adolescents with T2DM, there is some evidence that beta-cell dysfunction may be less severe. Our objective was to determine beta-cell sensitivity to glucose and maximal insulin secretory capacity (AIR(max)) in teenagers with T2DM.

METHODS

Fifteen adolescents with T2DM [11 F/4 M, age 18.4 +/- 0.3 yr, body mass index (BMI) 39.8 +/- 2.2 kg/m(2)] and 10 non-diabetic control subjects (7 F/3 M, age 17.4 +/- 0.5 yr, BMI 41.5 +/- 2.2 kg/m(2)) were studied. T2DM subjects had a mean duration of diabetes of 48.8 +/- 6.4 months, were treated with conventional therapies, and had good metabolic control [hemoglobin A1c (HbA1c) 6.7 +/- 1.2%]. Insulin and C-peptide were determined before and after a graded glucose infusion and after intravenous arginine at a whole blood glucose level of >or=22 mM.

RESULTS

The insulin response to increasing plasma glucose concentrations was blunted in the diabetic compared with control subjects (34.8 +/- 11.9 vs. 280.5 +/- 57.8 pmol/mmol; p < 0.0001), and AIR(max) was also significantly reduced in the diabetic group (1868 +/- 330 vs. 4445 +/- 606; p = 0.0005).

CONCLUSION

Even adolescents with well-controlled T2DM have severe impairments of insulin secretion. These data support beta-cell dysfunction as central in the pathogenesis of T2DM in young people, and indicate that these abnormalities can develop over a period of just several years.

Type 2 diabetes in children and adolescents

The emergence of Type 2 diabetes (T2D) in children and adolescents parallels the rising rates of childhood obesity. As a condition of impaired insulin sensitivity and relative insulin deficiency resulting in hyperglycemia, T2D has a complex underlying physiology that is reflected by the multiple approaches used to optimize medical care and prevent the myriad of diabetes-related complications. T2D diagnosed in children and adolescents represents a distinct and challenging condition to evaluate and treat. Here, we highlight the epidemiology, pathophysiology, risk factors, clinical presentation and diagnosis, treatment and public health impact of T2D in children and adolescents.

Bariatric surgery in young massively obese diabetic patients

Obesity is the most important lifestyle-related risk factor for type 2 diabetes (T2DM). The prevalence of T2DM in adolescents is increasing in parallel with the increasing incidence of major obesity. In adult obese subjects, the greatest degree of T2DM prevention, improvement or recovery has been reported in patients who have undergone bariatric surgery. However, few studies are available on the benefits and risks of bariatric surgery in adolescents with T2DM. The indications for obesity surgery in this population are unusual, and should only be considered in academic settings after comprehensive interdisciplinary evaluation.