Hyperglucagonemia Does Not Explain the β-Cell Hyperresponsiveness and Insulin Resistance in Dysglycemic Youth Compared With Adults: Lessons From the RISE Study

Altered postprandial glucose metabolism and enteropancreatic hormone responses during pregnancy following Roux-en-Y gastric bypass: a prospective cohort study

INTRODUCTION

Roux-en-Y gastric bypass (RYGB) increases the risk of postprandial hypoglycemia, whereas pregnancy decreases insulin sensitivity, which could be expected to counteract hypoglycemia. We examined if RYGB performed prior to pregnancy altered the postprandial glucose metabolism and enteropancreatic hormone responses to a mixed meal test (MMT).

RESEARCH DESIGN AND METHODS

Twenty-three women with RYGB and 23 women matched on prepregnancy body mass index and parity underwent a 4-hour MMT in the first and third trimester of pregnancy with measurement of circulating levels of glucose, insulin, C-peptide, glucose-dependent insulin peptide (GIP), glucagon-like peptide 1 (GLP-1), glucagon, free fatty acids, and lactate. Biochemical hypoglycemia was defined as plasma glucose <3.5 mmol/L.

RESULTS

Women with RYGB had earlier and higher peak glucose, lower nadir glucose levels, and a higher frequency of biochemical hypoglycemia compared with women without RYGB in both the first and third trimester. The lower glucose levels were preceded by markedly elevated total GLP-1 and insulin levels in women with RYGB, whereas total GIP levels were unaltered. The glucagon levels were lower in women with RYGB. In the first trimester MMT, peak and area under the curve of total plasma GLP-1 and serum insulin levels were negatively associated with nadir plasma glucose, while the early postmeal response of plasma glucagon was positively associated with nadir plasma glucose in the third trimester.

CONCLUSIONS

These results provide novel insights into the combined effects of RYGB and pregnancy on postmeal glucose metabolism and enteropancreatic hormone responses during pregnancy, and how these changes associate with an increased risk of postprandial hypoglycemia.

TRIAL REGISTRATION NUMBER

NCT03713060.

Glycemia, Insulin Sensitivity, and Secretion Improve 3 Months Post-sleeve Gastrectomy in Youth With Type 2 Diabetes

Context

Metabolic bariatric surgery reduces weight in youth with severe obesity; however, its impacts on youth-onset type 2 diabetes (T2D) are unclear.

Objective

We evaluated short-term outcomes in youth with T2D 3 months after vertical sleeve gastrectomy (VSG).

Design

Longitudinal, observational study in the Impact of Metabolic surgery on Pancreatic, Renal, and cardiOVascular hEalth in youth with T2D study (IMPROVE-T2D).

Setting

Academic medical university and children's hospital.

Participants

Fourteen youth with T2D [mean age ± SD 16.8 ± 1.4 years; 50% female, pre-VSG hemoglobin A1c (HbA1c) 6.6 ± 0.2%; diabetes duration 17.6 ± 13.8 months; age at diabetes diagnosis 15.9 ± 1.4 years; body mass index (BMI) 46.7 ± 2 kg/m2].

Interventions

Participants underwent a mixed-meal tolerance test (MMTT), body composition, and indirect calorimetry before and 3 months after VSG.

Main Outcomes

Glycemic control (HbA1c, diabetes medications), insulin sensitivity (Matsuda Index, Homeostasis Model of Insulin Sensitivity, oral minimal model), and secretion (C-peptide model).

Results

After VSG, weight and BMI decreased (25.2 ± 5.6 kg [19%], -8.7 ± 2 kg/m2 [18%], respectively, P < .001). Body fat decreased (4.5%, P = .012), with reductions of 14.1 ± 5.4 kg of fat mass (P = .005) and 4.5 kg of fat-free mass (P = .034). HbA1c decreased from 6.6 ± 0.2% to 5.7 ± 0.2% (P = .003), with 86% of participants no longer requiring diabetes medications. Glucose was lower throughout the MMTT, with insulin, C-peptide, free fatty acids, glucagon-like peptide-1, and peptide-YY significantly changing postsurgery (P < .05 for all). Insulin sensitivity and insulin secretion rate during the MMTT significantly improved.

Conclusion

Three months post-VSG, youth showed significant improvements in weight, body composition, insulin sensitivity and secretion, and glycemic control, with most no longer requiring diabetes medications.

Proteomic Analysis Uncovers Multiprotein Signatures Associated with Early Diabetic Kidney Disease in Youth with Type 2 Diabetes Mellitus

Key Points

Proteomics analyses identified seven proteins predictive of time to development of albuminuria among youth with type 2 diabetes in the Treatment Options for Type 2 Diabetes in Adolescents and Youth cohort, 118 proteins predictive of time to development of hyperfiltration, and three proteins predictive of time to rapid eGFR decline. Seven proteins were predictive of all three outcomes (SEM4A, PSB3, dihydroxyphenylalanine decarboxylase, C1RL1, T132A, pyruvate carboxylase, and C1-esterase inhibitor) and have been implicated in immune regulatory mechanisms, metabolic dysregulation, proteostasis, and cellular signaling pathways. Elastic net Cox proportional hazards model identified distinct multiprotein signatures (38–68 proteins) of time to albuminuria, hyperfiltration, and rapid eGFR decline with concordance for models with clinical covariates and selected proteins between 0.81 and 0.96, whereas the concordance for models with clinical covariates only was between 0.56 and 0.63.

Background

The onset of diabetic kidney disease (DKD) in youth with type 2 diabetes (T2D) mellitus often occurs early, leading to complications in young adulthood. Risk biomarkers associated with the early onset of DKD are urgently needed in youth with T2D.

Methods

We conducted an in-depth analysis of 6596 proteins (SomaScan 7K) in 374 baseline plasma samples from the Treatment Options for Type 2 Diabetes in Adolescents and Youth study to identify multiprotein signatures associated with the onset of albuminuria (urine albumin-to-creatinine ratio ≥30 mg/g), a rapid decline in eGFR (annual eGFR decline >3 ml/min per 1.73 m2 and/or ≥3.3% at two consecutive visits), and hyperfiltration (≥135 ml/min per 1.73 m2 at two consecutive visits). Elastic net Cox regression with ten-fold cross-validation was applied to the top 100 proteins (ranked by P value) to identify multiprotein signatures of time to development of DKD outcomes.

Results

Participants in the Treatment Options for Type 2 Diabetes in Adolescents and Youth study (14±2 years, 63% female, 7±6 months diabetes duration) experienced high rates of early DKD: 43% developed albuminuria, 48% hyperfiltration, and 16% rapid eGFR decline. Increased levels of seven and three proteins were predictive of shorter time to develop albuminuria and rapid eGFR decline, respectively; 118 proteins predicted time to development of hyperfiltration. Elastic net Cox proportional hazards models identified multiprotein signatures of time to incident early DKD with concordance for models with clinical covariates and selected proteins between 0.81 and 0.96, whereas the concordance for models with clinical covariates only was between 0.56 and 0.63.

Conclusions

Our research sheds new light on proteomic changes early in the course of youth-onset T2D that associate with DKD. Proteomic analyses identified promising risk factors that predict DKD risk in youth with T2D and could deepen our understanding of DKD mechanisms and potential interventions.

Clinical Trial registry name and registration number:

NCT00081328 .

Glucagon, Metabolic Dysfunction-Associated Steatotic Liver Disease and Amino Acids in Humans and Animals without Diabetes Mellitus-An Evidence Map

INTRODUCTION

Health systems are confronted with not only the growing worldwide childhood obesity epidemic but also associated comorbidities. These subsequently cause variations in distinct metabolic pathways, leading to metabolic dysfunction-associated steatotic liver disease (MASLD). The aim of this evidence map is to systematically evaluate the evidence and to identify research gaps on glucagon-induced amino acid (AA) turnover and its metabolic interaction with MASLD.

METHODOLOGY

A systematic literature search was conducted up to April 2023 in three electronic databases. Studies were required to include at least two of the main research areas, glucagon, AA metabolism and MASLD. Two independent reviewers screened titles and abstracts according to prespecified eligibility criteria, as well as full-text articles. Results are summarized in tables stratified by human and animal studies and study population age.

RESULTS

Thirty-four references were ultimately included. The publication years dated back to 1965 showed a great increase from 2012 to 2023. In total, there were 19 animal studies and 15 human studies. Among the human studies, except for two studies in adolescents, all the studies were conducted in adults. In human studies, the methods used to evaluate metabolic changes differed among hyperinsulinemic-euglycemic clamp and oral glucose tolerance tests. Thirteen studies focused on the metabolic effects of MASLD, while only two studies explored the interaction between MASLD, glucagon and AA metabolism in humans. The other 19 studies focused on metabolomics, beta cell function or just one topic of a research area and not on interactions between one another.

CONCLUSION

Research on the interaction between MASLD, glucagon and AA metabolism in humans is sparse and complete lacking in pediatrics. Furthermore, longitudinal studies with a focus on hyperglucagonemia independent of diabetes but related to MASLD present an unambiguous research gap.

Insulin Dynamics and Pathophysiology in Youth-Onset Type 2 Diabetes

Youth-onset type 2 diabetes (T2D) is increasing around the globe. The mounting disease burden of youth-onset T2D portends substantial consequences for the health outcomes of young people and for health care systems. The pathophysiology of this condition is characterized by insulin resistance and initial insulin hypersecretion ± an inherent insulin secretory defect, with progressive loss of stimulated insulin secretion leading to pancreatic β-cell failure. Research studies focusing on youth-onset T2D have illuminated key differences for youth- vs adult-onset T2D, with youth having more profound insulin resistance and quicker progression to loss of sufficient insulin secretion to maintain euglycemia. There is a need for therapies that are targeted to improve both insulin resistance and, importantly, maintain sufficient insulin secretory function over the lifespan in youth-onset T2D.

Rise in fasting and dynamic glucagon levels in children and adolescents with obesity is moderate in subjects with impaired fasting glucose but accentuated in subjects with impaired glucose tolerance or type 2 diabetes

Background

Fasting levels of glucagon are known to be elevated in youth and adults with type 2 diabetes mellitus (T2D). Children and adolescents with obesity were previously reported to show increasing fasting and post-glucose-challenge hyperglucagonemia across the spectrum of glucose tolerance, while no data are available in those with impaired fasting glucose (IFG).

Materials and methods

Individuals from the Beta-JUDO study population (Uppsala and Salzburg 2010-2016) (n=101, age 13.3 ± 2.8, m/f =50/51) were included (90 with overweight or obesity, 11 with normal weight). Standardized OGTT were performed and plasma glucose, glucagon and insulin concentrations assessed at baseline, 5, 10, 15, 30, 60, 90 and 120 minutes. Patients were grouped according to their glycemic state in six groups with normal glucose metabolism (NGM) and normal weight (NG-NW), NGM with obesity or overweight (NG-O), impaired glucose tolerance (IGT), impaired fasting glucose (IFG), IGT+IFG and T2D, and in two groups with NGM and impaired glucose metabolism (IGM), for statistical analysis.

Results and conclusion

Glucagon concentrations were elevated in young normoglycemic individuals with overweight or obesity (NG-O) compared to normoglycemic individuals with normal weight. Glucagon levels, fasting and dynamic, increased with progressing glycemic deterioration, except in IFG, where levels were comparable to those in NG-O. All glycemic groups showed an overall suppression of glucagon during OGTT. An initial increase of glucagon could be observed in T2D. In T2D, glucagon showed a strong direct linear correlation with plasma glucose levels during OGTT. Glucagon in adolescents, as in adults, may play a role in the disease progression of T2D.

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.

Beta Cell Dysfunction in Youth- and Adult-Onset Type 2 Diabetes: An Extensive Narrative Review with a Special Focus on the Role of Nutrients

Traditionally a disease of adults, type 2 diabetes (T2D) has been increasingly diagnosed in youth, particularly among adolescents and young adults of minority ethnic groups. Especially, during the recent COVID-19 pandemic, obesity and prediabetes have surged not only in minority ethnic groups but also in the general population, further raising T2D risk. Regarding its pathogenesis, a gradually increasing insulin resistance due to central adiposity combined with a progressively defective β-cell function are the main culprits. Especially in youth-onset T2D, a rapid β-cell activity decline has been observed, leading to higher treatment failure rates, and early complications. In addition, it is well established that both the quantity and quality of food ingested by individuals play a key role in T2D pathogenesis. A chronic imbalance between caloric intake and expenditure together with impaired micronutrient intake can lead to obesity and insulin resistance on one hand, and β-cell failure and defective insulin production on the other. This review summarizes our evolving understanding of the pathophysiological mechanisms involved in defective insulin secretion by the pancreatic islets in youth- and adult-onset T2D and, further, of the role various micronutrients play in these pathomechanisms. This knowledge is essential if we are to curtail the serious long-term complications of T2D both in pediatric and adult populations.

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.

The relationship between glucose and the liver-alpha cell axis - A systematic review

Until recently, glucagon was considered a mere antagonist to insulin, protecting the body from hypoglycemia. This notion changed with the discovery of the liver-alpha cell axis (LACA) as a feedback loop. The LACA describes how glucagon secretion and pancreatic alpha cell proliferation are stimulated by circulating amino acids. Glucagon in turn leads to an upregulation of amino acid metabolism and ureagenesis in the liver. Several increasingly common diseases (e.g., non-alcoholic fatty liver disease, type 2 diabetes, obesity) disrupt this feedback loop. It is important for clinicians and researchers alike to understand the liver-alpha cell axis and the metabolic sequelae of these diseases. While most of previous studies have focused on fasting concentrations of glucagon and amino acids, there is limited knowledge of their dynamics after glucose administration. The authors of this systematic review applied PRISMA guidelines and conducted PubMed searches to provide results of 8078 articles (screened and if relevant, studied in full). This systematic review aims to provide better insight into the LACA and its mediators (amino acids and glucagon), focusing on the relationship between glucose and the LACA in adult and pediatric subjects.

ISPAD Clinical Practice Consensus Guidelines 2022: Type 2 diabetes in children and adolescents

Since the 2018 ISPAD guidelines on this topic, follow-up of large cohorts from around the globe have continued informing the current incidence and prevalence of co-morbidities and complications in young adults with youth-onset type 2 diabetes (T2D). This chapter focuses on the risk factors, diagnosis and presentation of youth-onset T2D, the initial and subsequent management of youth-onset T2D, and management of co-morbidities and complications. We include key updates from the observational phase of the multi-center Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) clinical trial, the SEARCH for Diabetes in Youth (SEARCH) study and new data from the Restoring Insulin Secretion (RISE) study, a head-to-head comparison of youth onset vs adult-onset T2D. We also include an expanded section on risk factors associated with T2D, algorithms and tables for treatment, management, and assessment of co-morbidities and complications, and sections on recently approved pharmacologic therapies for the treatment of youth-onset T2D, social determinants of health, and settings of care given COVID-19 pandemic.

Hyperglucagonemia in Pediatric Adiposity Associates With Cardiometabolic Risk Factors but Not Hyperglycemia

CONTEXT

In adults, hyperglucagonemia is associated with type 2 diabetes, impaired glucose tolerance, and obesity. The role of glucagon in pediatric overweight/obesity remains unclear.

OBJECTIVE

We examined whether fasting concentrations of glucagon are elevated in youth with overweight/obesity and whether this associates with cardiometabolic risk profiles.

METHODS

Analyses were based on the cross-sectional HOLBAEK study, including children and adolescents 6 to 19 years of age, with overweight/obesity from an obesity clinic group (n = 2154) and with normal weight from a population-based group (n = 1858). Fasting concentrations of plasma glucagon and cardiometabolic risk outcomes were assessed, and multiple linear and logistic regressions models were performed.

RESULTS

The obesity clinic group had higher glucagon concentrations than the population-based group (P < 0.001). Glucagon positively associated with body mass index (BMI) standard deviation score (SDS), waist, body fat %, liver fat %, alanine transaminase (ALT), high-sensitivity C-reactive protein, homeostasis model assessment of insulin resistance, insulin, C-peptide, LDL-C, triglycerides, SDS of diastolic and systolic blood pressure, and was inversely associated with fasting glucose. The inverse relationship between glucagon and glucose was attenuated in individuals with high BMI SDS and high fasting insulin. Glucagon was associated with a higher prevalence of insulin resistance, increased ALT, dyslipidemia, and hypertension, but not with hyperglycemia. Glucagon was positively associated with fasting total glucagon-like peptide-1.

CONCLUSION

Compared with normal weight peers, children and adolescents with overweight/obesity had elevated concentrations of fasting glucagon, which corresponded to worsened cardiometabolic risk outcomes, except for hyperglycemia. This suggests hyperglucagonemia in youth may precede impairments in glucose regulation.

Effect of Medical and Surgical Interventions on α-Cell Function in Dysglycemic Youth and Adults in the RISE Study

OBJECTIVE

To compare effects of medications and laparoscopic gastric band surgery (LB) on α-cell function in dysglycemic youth and adults in the Restoring Insulin Secretion (RISE) Study protocols.

RESEARCH DESIGN AND METHODS

Glucagon was measured in three randomized, parallel, clinical studies: 1) 91 youth studied at baseline, after 12 months on metformin alone (MET) or glargine followed by metformin (G/M), and 3 months after treatment withdrawal; 2) 267 adults studied at the same time points and treated with MET, G/M, or liraglutide plus metformin (L+M) or given placebo (PLAC); and 3) 88 adults studied at baseline and after 12 and 24 months of LB or MET. Fasting glucagon, glucagon suppression by glucose, and acute glucagon response (AGR) to arginine were assessed during hyperglycemic clamps. Glucagon suppression was also measured during oral glucose tolerance tests (OGTTs).

RESULTS

No change in fasting glucagon, steady-state glucagon, or AGR was seen at 12 months following treatment with MET or G/M (in youth and adults) or PLAC (in adults). In contrast, L+M reduced these measures at 12 months (all P ≤ 0.005), which was maintained 3 months after treatment withdrawal (all P < 0.01). LB in adults also reduced fasting glucagon, steady-state glucagon, and AGR at 12 and 24 months (P < 0.05 for all, except AGR at 12 months [P = 0.098]). Similarly, glucagon suppression during OGTTs was greater with L+M and LB. Linear models demonstrated that treatment effects on glucagon with L+M and LB were largely associated with weight loss.

CONCLUSIONS

Glucagon concentrations were reduced by L+M and LB in adults with dysglycemia, an effect principally attributable to weight loss in both interventions.