Glycemia and Gluconeogenesis With Metformin and Liraglutide: A Randomized Trial in Youth-onset Type 2 Diabetes

OBJECTIVE

Elevated rates of gluconeogenesis are an early pathogenic feature of youth-onset type 2 diabetes (Y-T2D), but targeted first-line therapies are suboptimal, especially in African American (AA) youth. We evaluated glucose-lowering mechanisms of metformin and liraglutide by measuring rates of gluconeogenesis and β-cell function after therapy in AA Y-T2D.

METHODS

In this parallel randomized clinical trial, 22 youth with Y-T2D-age 15.3 ± 2.1 years (mean ± SD), 68% female, body mass index (BMI) 40.1 ± 7.9 kg/m2, duration of diagnosis 1.8 ± 1.3 years-were randomized to metformin alone (Met) or metformin + liraglutide (Lira) (Met + Lira) and evaluated before and after 12 weeks. Stable isotope tracers were used to measure gluconeogenesis [2H2O] and glucose production [6,6-2H2]glucose after an overnight fast and during a continuous meal. β-cell function (sigma) and whole-body insulin sensitivity (mSI) were assessed during a frequently sampled 2-hour oral glucose tolerance test.

RESULTS

At baseline, gluconeogenesis, glucose production, and fasting and 2-hour glucose were comparable in both groups, though Met + Lira had higher hemoglobin A1C. Met + Lira had a greater decrease from baseline in fasting glucose (-2.0 ± 1.3 vs -0.6 ± 0.9 mmol/L, P = .008) and a greater increase in sigma (0.72 ± 0.68 vs -0.05 ± 0.71, P = .03). The change in fractional gluconeogenesis was similar between groups (Met + Lira: -0.36 ± 9.4 vs Met: 0.04 ± 12.3%, P = .9), and there were no changes in prandial gluconeogenesis or mSI. Increased glucose clearance in both groups was related to sigma (r = 0.63, P = .003) but not gluconeogenesis or mSI.

CONCLUSION

Among Y-T2D, metformin with or without liraglutide improved glycemia but did not suppress high rates of gluconeogenesis. Novel therapies that will enhance β-cell function and target the elevated rates of gluconeogenesis in Y-T2D are needed.

Reevaluating First-line Therapies in Youth-Onset Type 2 Diabetes

The prevalence of youth-onset type 2 diabetes is growing worldwide and current first-line treatment with metformin and intensive behavior and lifestyle changes are suboptimal in over 50% of youth within 2 years of diagnosis. This perspective article is a call to action for reevaluation of existing strategies and critical appraisal of metformin as first-line therapy in youth-onset type 2 diabetes. Increased attention should be given to novel therapeutics approved in youth, including glucagon-like 1 receptor agonists, sodium glucose cotransporter-2, and sociocultural interventions that will promote diabetes self-management.

Abstract P560: Pilot Study Reveals Excellent Agreement in the Diagnosis of Diabetes Between the Newly Developed Pastry Sugar Tolerance Test and the OGTT: Africans in America Study

Introduction: Sub-Saharan Africa has the highest percentage of people in the world living with diabetes who are undiagnosed. To avoid end-organ damage, identification of undiagnosed diabetes needs prioritization. Glucola (75g glucose) used for the oral glucose tolerance test (OGTT) is expensive and rarely available in sub-Saharan Africa. Due to hemoglobinopathies, G6PD deficiency, and challenges associated with fasting, both A1C and fasting plasma glucose (FPG) may be diagnostically unreliable. As an alternative to the OGTT, we developed the Pastry Sugar Tolerance Test (PSTT). For the PSTT, pastry sugar (75g glucose powder) is dissolved in hot water. Pastry sugar is more widely available in sub-Saharan Africa and nine times less expensive than Glucola.

Objective: Our goals were to determine the diagnostic agreement for the detection of diabetes between the OGTT and: (1) PSTT, (2) A1C and (3) FPG.

Methods: The participants were 36 African-born Blacks enrolled in the Africans in America study (male: 67%; age: 42±10y (mean±SD); BMI: 28.5±5.2 kg/m2). At Visit 1, each enrollee had an OGTT, A1C and FPG. At Visit 2, which occurred 8±3 days after Visit 1, a PSTT was performed. Glucose tolerance status was based on glucose results from the OGTT. The kappa-statistic was used to determine the diagnostic agreement between the OGTT and each of the following: PSTT, A1C and FPG.

Results: Based on the OGTT, diabetes, prediabetes and normal glucose tolerance occurred in 11%(4/36), 33%(12/36) and 56%(20/36) resp. For diabetes, diagnostic agreement between the OGTT and PSTT was excellent (κ=0.99) but much lower for the OGTT and A1C (κ=0.64) and the OGTT and FPG (κ=0.38) (Figure).

Conclusions: This pilot study has revealed that for diabetes screening, the PSTT has excellent diagnostic agreement with the OGTT, is less expensive than the OGTT, and is more accurate than A1C or FPG.

The effects of prebiotics on gastrointestinal side effects of metformin in youth: A pilot randomized control trial in youth-onset type 2 diabetes

Disclosure summary

Dr. Yadav is Chief Scientific Officer and Co-Founder of Postbiotics Inc and has no conflict of interest with this work. All other authors have no conflicts of interest to disclose.

Background

Metformin is the only approved first-line oral glucose lowering agent for youth with type 2 diabetes mellitus (Y-T2DM) but often causes gastrointestinal (GI) side effects, which may contribute to reduced treatment adherence and efficacy. Prebiotic intake may reduce metformin's side effects by shifting microbiota composition and activity.

Objective

The aims of this study were to determine the feasibility and tolerability of a prebiotic supplement to improve metformin-induced GI symptoms and explore the changes in glycemia and shifts in the microbiota diversity.

Methods

In a two-phase pilot clinical trial, we compared, stool frequency and stool form every 1-2 days, and composite lower GI symptoms (weekly) at initiation of daily metformin combined with either a daily prebiotic or a placebo shake in a 1-week randomized double-blind crossover design (Phase 1), followed by a 1-month open-labeled extension (Phase 2). Plasma glycemic markers and stool samples were collected before and after each phase.

Results

Six Y-T2DM (17.2 ± 1.7y (mean ± SD), 67% male, BMI (42 ± 9 kg/m2), HbA1c (6.4 ± 0.6%)) completed the intervention. Stool frequency, stool composition, and GI symptom scores did not differ by group or study phase. There were no serious or severe adverse events reported, and no differences in metabolic or glycemic markers. After one week Phase 1metformin/placebo Proteobacteria, Enterobacteriaceae, and Enterobacteriales were identified as candidate biomarkers of metformin effects. Principle coordinate analyses of beta diversity suggested that the metformin/prebiotic intervention was associated with distinct shifts in the microbiome signatures at one week and one month.

Conclusion

Administration of a prebiotic fiber supplement during short-term metformin therapy was well tolerated in Y-T2DM and associated with modest shifts in microbial composition. This study provides a proof-of-concept for feasibility exploring prebiotic-metformin-microbiome interactions as a basis for adjunctive metformin therapy.

Clinical trial registration

https://clinicaltrials.gov/, identifier NCT04209075.

Lipoprotein Insulin Resistance Score: Validation and Utility in African Ancestry Populations

Lipoprotein insulin resistance (LPIR) is an emerging biomarker of insulin resistance (IR), and a score of >48 is a strong predictor of incident cardiometabolic disease disease in a predominantly European ancestry population. LPIR is derived from a composite score of nuclear magnetic resonance (NMR) lipoprotein (Lp) parameters: triglyceride-rich (TRLp), low density (LDLp), and high density (HDLp). Yet, there is a paucity of data in African ancestry population, in whom there is low-normal TRLp despite high rates of IR and diabetes. Therefore, we examined Lp profiles and LPIR in a large African ancestry cohort, stratified by sex to determine the relationship of LPIR with established markers of IR. This is a secondary analysis from 2 studies (The Africans in America and Federal Women’s Study) designed to evaluate the genetic, biological and socio-environmental factors of diabetes risk in those of African ancestry. All participants self-identified as healthy and lived in the DC metro area, n= 518: 87.7% African immigrant,12.3% African American; age 39±10 (20-65y); BMI 28.1±4.8 (18.2–45.2 kg/m2); 58% male; 31% with obesity, and 37% with abnormal glucose tolerance; mean±SD (range); median (25th-75th percentile). Fasting measures of IR (LPIR, triglyceride/HDL (TG/HDL) ratio and homeostasis model of insulin resistance (HOMA-IR)) were compared with the whole-body insulin sensitivity index (WBISI) obtained during a multi-sample 75g OGTT, using spearman correlations. Lp particle size and subclass concentrations were measured by the amplitudes of the lipid-methyl group signals (NMR LipoProfile®). Men had lower BMI (27.1±3.9 vs 29.3±5.6 kg/m2), fat mass (23.5±5.5 vs 37.9±6.8 %), insulin resistance (WBISI: 6.2 (3.7–10.1) vs 4.9 (3.2–8.6), HOMA-IR: 1.3 (0.7–2.0) vs 1.6 (0.9–2.4), TG/HDL: 1.4 (1.0–2.2) vs 1.1 (0.8–1.5)), all P<0.001. LDLp (1226 (959–1531) vs 1239 (981–1553) nmol/L) and HDLp (17.6 (16.2–19) vs 17.5 (15.9–19.7) µmol/L) were similar by sex, P>0.6, while small LDLp 734 (523–1039) vs 541 (370–805) nmol/L and TRLp 80.5 (52.2–116.4) vs 53.6 (28.7 -89.3) nmol/L were higher in men. The total mean LPIR score was 28.9±18.7 and was higher in men (34±19 vs. 23±17), P<0.001. LPIR and TG/HDL ratio correlated with WBISI (r≥-0.40) and HOMA-IR (r≥0.40), P<0.001 with no differences by sex. HOMA-IR correlated with WBISI (r=-0.95, P<0.001). Overall, African ancestry individuals had high rates of abnormal glucose tolerance, obesity and LDLp but LPIR was 20 points lower than the established score for predicting cardiometabolic disease. It’s utility for detecting IR was modest but it may be an important adjunct for early cardiometabolic risk stratification in African ancestry populations in whom traditional screening methods have lower sensitivity.

Triglyceride Paradox Is Related to Lipoprotein Size, Visceral Adiposity and Stearoyl-CoA Desaturase Activity in Black Versus White Women

RATIONALE

In black women, triglycerides are paradoxically normal in the presence of insulin resistance. This relationship may be explained by race-related differences in central adiposity and SCD (stearoyl-CoA desaturase)-1 enzyme activity index.

OBJECTIVE

In a cross-sectional study, to compare fasting and postprandial triglyceride-rich lipoprotein particle (TRLP) concentrations and size in black compared with white pre- and postmenopausal women and determine the relationship between TRLP subfractions and whole-body insulin sensitivity, hepatic and visceral fat, and SCD-1 levels.

METHODS AND RESULTS

In 122 federally employed women without diabetes mellitus, 73 black (58 African American and 15 African immigrant) and 49 white; age, 44±10 (mean±SD) years; body mass index, 30.0±5.6 kg/m², we measured lipoprotein subfractions using nuclear magnetic resonance. Hepatic fat was measured by proton magnetic resonance spectroscopy, insulin sensitivity index calculated by minimal modeling from a frequently sampled intravenous glucose test, and red blood cell fatty acid profiles were measured by gas chromatography and were used to estimate SCD-1 indices. Hepatic fat, insulin sensitivity index, and SCD-1 were similar in black women and lower than in whites, regardless of menopausal status. Fasting and postprandial large, medium, and small TRLPs, but not very small TRLPs, were lower in black women. Fasting large, medium, and very small TRLPs negatively correlated with insulin sensitivity index and positively correlated with visceral and hepatic fat and SCD-1 activity in both groups. In multivariate models, visceral fat and SCD-1 were associated with total fasting TRLP concentrations (adjR2, 0.39; P=0.001). Black women had smaller postprandial changes in large (P=0.005) and medium TRLPs (P=0.007).

CONCLUSIONS

Lower visceral fat and SCD-1 activity may contribute to the paradoxical association of lower fasting and postprandial TRLP subfractions despite insulin resistance in black compared with white pre- and postmenopausal women. Similar concentrations of very small TRLPs are related to insulin resistance and could be important mediators of cardiometabolic disease risk in women.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01809288.