Sex Differences in Branched-chain Amino Acid and Tryptophan Metabolism and Pathogenesis of Youth-onset Type 2 Diabetes

OBJECTIVES

Insulin resistance is associated with elevations in plasma branched-chain amino acids (BCAAs). BCAAs compete with aromatic amino acids including tryptophan for uptake into β cells. To explore relationships between BCAAs and tryptophan metabolism, adiposity, and glucose tolerance, we compared urine metabolites in overweight/obese youth with type 2 diabetes (T2D) with those in nondiabetic overweight/obese and lean youth.

METHODS

Metabolites were measured in 24-hour and first-morning urine samples of 56 nondiabetic adolescents with overweight/obesity, 42 adolescents with T2D, and 43 lean controls, aged 12 to 21 years. Group differences were assessed by Kruskal Wallis or ANOVA.

RESULTS

Groups were comparable for age, pubertal status, and ethnicity. Youth with T2D were predominantly female and had highest percent body fat. BCAAs, branched-chain ketoacids (BCKAs), tryptophan, and kynurenine were higher in urine of subjects with T2D. There were no differences between lean controls and nondiabetic youth with overweight/obesity. T2D was associated with diversion of tryptophan from the serotonin to the kynurenine pathway, with higher urinary kynurenine/serotonin ratio and lower serotonin/tryptophan and 5-HIAA/kynurenine ratios. Urinary BCAAs, BCKAs, tryptophan, and ratios reflecting diversion to the kynurenine pathway correlated positively with metrics of body fat and hemoglobin A1c. Increases in these metabolites in the obese T2D group were more pronounced and statistically significant only in adolescent girls.

CONCLUSION

Increases in urinary BCAAs and BCKAs in adolescent females with T2D are accompanied by diversion of tryptophan metabolism from the serotonin to the kynurenine pathway. These adaptations associate with higher risks of T2D in obese adolescent females than adolescent males.

Disrupted Pediatric Diabetes Trends in the Second Year of the COVID-19 Pandemic

Context

Increases in incident cases of pediatric type 1 (T1D) and type 2 diabetes (T2D) were observed during the first year of the COVID-19 pandemic.

Objective

This work aimed to identify trends in incidence and presentation of pediatric new-onset T1D and T2D during the second year of the COVID-19 pandemic.

Methods

A retrospective chart review was conducted. Demographics, anthropometrics, and initial laboratory results from patients aged 0 to 21 years who presented with new-onset diabetes to a pediatric tertiary care center were recorded.

Results

The incident cases of T1D (n = 46) and T2D (n = 46) in 2021-2022 (second year of the pandemic) were consistent with the incident cases of T1D (n = 46) and T2D (n = 53) in 2020 to 2021 (first year of the pandemic). Compared to the incident cases of diabetes in the prepandemic years, in the second year, the incident cases of T1D increased 48%, and the incident cases of T2D increased 188%. In the second year of the pandemic, incident cases of T2D represented half (50%) of all newly diagnosed pediatric diabetes cases. Patients with T2D were more likely to present in diabetic ketoacidosis, though this was not statistically significant (P = .08).

Conclusion

The increase in incident cases of pediatric T1D and T2D observed during the first year of the COVID-19 pandemic persisted during the second pandemic year. This suggests that despite pediatric vaccination efforts and return to social in-person activities, we may continue to see effects of the pandemic on pediatric diabetes trends.