bluuebunny/crossref_metadata_2025 huggingface dataset:
1461-P: HbA1c-Independent Association between DNA Methylation (DNAm) and 28-Year Risk of Microvascular Complications in Type 1 Diabetes (T1D)
Authors: MILLER RACHEL G. , MYCHALECKYJ JOSYF , ONENGUT-GUMUSCU SUNA , ORCHARD TREVOR J. , COSTACOU TINA
Published: June 2023

DNAm has been associated with microvascular disease but the few epigenome-wide association studies (EWAS) of complications in T1D were largely cross-sectional with limited data on glycemic exposure. We thus performed separate EWAS of 28-yr overt nephropathy (ON) and proliferative retinopathy (PR) risk to determine whether DNAm associations are independent of concurrent HbA1c or differ by long-term HbA1c trajectory in the Pittsburgh Epidemiology of Diabetes Complications study of childhood onset (<17 yrs) T1D (baseline mean age 29, T1D duration 21 yrs). After quality control, baseline whole blood DNAm (Illumina EPIC array) at 683,597 CpGs was analyzed in Cox models for time-to-ON (albumin excretion rate >200µg/min in ≥2 of 3 timed urines, n=306 free of ON at baseline) and PR (ETDRS grade≥60 or laser photocoagulation, n=265 free of PR), adjusting for T1D duration, sex, smoking pack-years, est. blood cell composition, and technical covariates. Additional EWAS further adjusted for baseline HbA1c. CpGs with false discovery rate (FDR) <0.20 were examined by previously derived latent HbA1c trajectory (Low: stable 7-8%, Improved: 10% decreasing to 7%, Intermediate-High: stable 9%-11%). Over 28 yrs, 65 (21.2%) developed ON; 139 (52.5%) PR. For ON, DNAm at cg19693031 (TXNIP) was associated (β per 5% DNAm=−0.43±0.09, p=2.84E-07, FDR=0.19) but attenuated in a baseline HbA1c-adjusted EWAS (β=−0.32±0.08, p=7.76E-05, FDR=0.98). For PR, 3 CpGs (cg27512687 [KIF16B]; cg04202206 [ISCA1]; cg14678509 [intergenic]) had FDR<0.20; only cg27512687 remained so after HbA1c adjustment (β=−2.6±0.49, p=8.46E-08, FDR=0.06). There was no interaction with baseline HbA1c (p=0.49); the magnitude of the cg27512687-PR association was similar regardless of HbA1c trajectory. Thus, further study of cg27512687 in KIF16B, a locus encoding a kinesin involved in receptor recycling/degradation, is warranted as it may make an HbA1c-independent contribution to PR risk T1D.

Disclosure

R.G.Miller: None. J.Mychaleckyj: None. S.Onengut-gumuscu: None. T.J.Orchard: None. T.Costacou: None.

Funding

American Diabetes Association (1-19-JDF-109 to R.G.M.); National Institute of Diabetes and Digestive and Kidney Diseases (R01DK034818)
1464-P: Identification of Candidate Biomarkers for Type 1 Diabetes Mellitus by Bioinformatics Analysis of Pooled Microarray Gene Expression Datasets in Gene Expression Omnibus
Authors: FENG KEVIN
Published: June 2023

Background: Type 1 diabetes (T1DM) is a serious threat to childhood life and has a complicated pathogenesis. Currently, molecular mechanisms of T1DM remain largely unclear. The aim of this study was to identify the candidate genes in T1DM by integrated bioinformatics analysis.

Methods: Transcriptomic datasets (GSE156035) in the GEO database were analyzed for differentially expressed genes (DEGs) using the R statistical language. The differentially expressed genes (DEGs) were identified, and the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed. A protein - protein interaction (PPI) network was applied to screen out the candidate genes.

Results: The results revealed that 273 DEGs of the three datasets were ascertained in our study, including 135 upregulated genes and 138 downregulated genes. The GO and KEGG enrichment analysis results showed that the functions of DEGs mainly involved in regulation of transcription from RNA polymerase II promoter, specific granule lumen, transcriptional activator activity, Osteoclast differentiation pathway, etc. Through the PPI analysis network, the core genes with the highest degree of 6 nodes were selected: FOS, RHOA, CXCL8, FOSB, EGR1, and DUSP1.

Conclusion: The genes, identified in this study, may play a vital regulatory role in the occurrence and development of T1DM. Also, they are closely related to obesity and diabetes mellitus. Our results provide novel biomarkers that could be used as representative reference indicators or potential therapeutic targets for T1DM clinical applications.

Disclosure

K.Feng: None.

Funding

SBHS (2022-16)
1468-P: Integrating Whole-Genome Sequence Analysis and eQTL Data from the TOPMed Program Improves Understanding of Type 2 Diabetes Risk Loci in Diverse Populations
Authors: WANG NINGYUAN , DICORPO DANIEL A. , ZHANG YIXIN , WESSEL JENNIFER , MANNING ALISA
Published: June 2023

Type 2 diabetes (T2D) has been well characterized by genetic studies with over 550 risk loci identified in mostly European populations. To better understand the genetic basis of T2D in diverse ancestries, we performed a whole genome sequence association analysis with T2D and related traits of fasting insulin (FI), glucose (FG) and hemoglobin A1c (HbA1c). We then used the colocalization method COLOC to evaluate if the risk locus and expression quantitative trait loci (eQTL) region shared a variant. Four relevant eQTL specific to tissues or cell types were obtained from the NHLBI Trans Omics for Precision Medicine (TOPMed) program, including 6,602 samples for whole blood, 1,265 for peripheral blood mononuclear cells (PBMC), 368 for T cells, and 352 for monocytes. A signal was considered colocalized if the posterior probability of colocalization (PP.coloc) was >0.5.

Our analysis included 21,913 prevalent T2D cases, 61,036 controls, and up to 50,201 non-T2D individuals with FG, FI or HbA1c from African, Atlantic Islander, East Asian, European, Hispanic, and Samoan groups. Single variant analysis identified 35 variants in known regions that were significantly associated with T2D or related traits (P < 4.00 × 10−9). Among these regions, we detected six genes (SLC2A2, NKX6-3, KCNQ1, HBB, FN3K, and G6PD) having colocalizing signals in at least one relevant tissue or cell type. For example, variant rs1050828 near G6PD on chromosome X was strongly associated with HbA1c (P <1.0×10−200). Colocalization analysis revealed that rs1050828 also affected the gene expression in various tissues or cell types, including BCAP31 in whole blood, TKTL1 in PBMC, MPP1 in T cell, and RENBP in monocytes. This novel finding, obtained using TOPMed eQTL data from multiple cohorts, suggests a link between risk-associated variation and effector genes, providing insight into potential causal genes and regulatory variants at T2D risk loci in diverse populations.

Disclosure

N.Wang: None. D.A.Dicorpo: None. Y.Zhang: None. J.Wessel: None. A.Manning: None. Topmed diabetes working group: n/a.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (UM1DK078616, R01HL151855)
1469-P: Gene-Level Gene–Mediterranean Diet Interaction Detection Influencing Inflammatory and Glycemic Biomarkers in 137,000 UK Biobank Participants
Authors: WESTERMAN KENNETH E. , MEIGS JAMES B. , MANNING ALISA
Published: June 2023

Adherence to a Mediterranean diet pattern strongly reduces type 2 diabetes risk on average, but there is substantial heterogeneity in the long-term glycemic and inflammatory response to dietary changes, likely due in part to genetic factors. Using a genome-wide interaction association analysis in the UK Biobank (UKB) cohort, we sought to prioritize and characterize genes contributing to this heterogeneity in the Mediterranean diet-risk factor relationship. We studied an unrelated, multi-ancestry UKB subset who completed at least one 24-hour diet questionnaire, had available glycemic (hemoglobin A1c; HbA1c) and inflammatory (high-sensitivity C-reactive protein; hsCRP) biomarkers measured in blood, and were free of major disease at baseline (N = 136,880). A nine-item, point-based Mediterranean diet score (MDS) based on food group and nutrient intakes was calculated. We conducted a series of genome-wide interaction studies (GWIS) to test for significant variant-diet interactions: one for the MDS itself and one for each sub-component. Variant-level results were aggregated by gene using the MAGMA tool. Gene-level MDS interaction results revealed two genes with false discovery rate < 0.1 for HbA1c: LRRC24 (p = 3.2×10−6) and CCDC40 (p = 3.3×10−6). Gene-level sub-component-specific analysis showed that these two interactions were primarily driven by alcohol and fish intake, respectively, and further prioritized an interaction between intake of nuts and LIN9 gene variants impacting HbA1c (p = 8.8×10−8). Follow-up analysis at the top variant in LIN9, rs9729447, showed a substantial attenuation of the negative nut intake-HbA1c association in major allele carriers and revealed a stronger interaction effect size in individuals who completed at least two dietary questionnaires. Our GWIS analysis suggests that there are locus-specific interactors with Mediterranean diet patterns influencing glycemic and inflammatory health.

Disclosure

K.E.Westerman: None. J.B.Meigs: Consultant; Quest Diagnostics. A.Manning: None.

Funding

National Institutes of Health (K01DK133637)
1470-P: Novel Associations of Glycometabolic Traits in Ethnically Diverse Africans
Authors: HANSEN MATTHEW , HARRIS DANIEL , HARRIS ALEXANDRE M. , NYAMBO THOMAS B. , BELAY GURJA , MPOLOKA SUNUNGUKO , BURANT CHARLES , TISHKOFF SARAH A.
Published: June 2023

Prior studies have identified genetic factors that impact an individual’s risk of developing type 2 diabetes (T2D). However, African ancestry is underrepresented in genetic studies despite the higher prevalence of T2D in African Americans compared to European or Asian Americans. To better understand risk factors for this health disparity, we used a unique dataset of T2D biomarkers (C-peptide and standing glucose) and ~5 million single nucleotide polymorphism genotypes from an ethnically diverse sampling of sub-Saharan Africans (N~1,250) to identify genetic variants associated with these traits. Because the individuals in our dataset practice traditional subsistence patterns and live in rural settings, there is less environmental heterogeneity than observed in urban settings. Between both traits, we uncovered hundreds of novel marginal associations (p<10−5) and three genome-wide significant associations (p<5×10−8), one with C-peptide (rs147703855, in DAAM1) and two with glucose (rs74085215, near KLC1; rs951516, intergenic). The minor alleles for these three associations are rare outside of Africa (<0.1%) but attain frequencies ~5-10% in at least one African ancestry group. Although none of these associations have been previously reported, the genes near the marginal C-peptide associations (<200kbp) are enriched for variants with previously reported T2D associations (GWAS catalogue), as well as chylomicron, VLDL, and triglyceride associations. The genes near our marginal glucose associations were not found to be enriched for previously reported T2D associations (p>0.05), though they were significantly enriched for body size, chylomicron, and triglyceride associations (p<0.006). We are following up this preliminary study with an expanded GWAS using a new proteomics dataset in ~500 subjects, and a metabolomics dataset in ~700 subjects. These data will be used to construct polygenic risk scores for biomarkers of T2D that are more effective in people of recent African descent.

Disclosure

M.Hansen: None. D.Harris: None. A.M.Harris: None. T.B.Nyambo: None. G.Belay: None. S.Mpoloka: None. C.Burant: Research Support; Rhythm Pharmaceuticals, Inc. S.A.Tishkoff: None.

Funding

American Diabetes Association (1-19-VSN-02 to S.A.T.); National Institutes of Health (R35GM134922)
1471-P: Metabolomic Profiling of Type 2 Diabetes Pathway-Partitioned Polygenic Risk Scores Offers Insights into Disease Etiology
Authors: SEVILLA MAGDALENA , LAMIQUIZ-MONEO ITZIAR , SMITH KIRK , CANYELLES MARINA , FLOREZ JOSE C. , MANNING ALISA , CIVEIRA FERNANDO , MERINO JORDI , UDLER MIRIAM
Published: June 2023

Previous studies have identified type 2 diabetes (T2D) subtypes using clinical phenotypes and/or genetic information. This study aimed to identify molecular signatures associated with genetically based T2D subtypes. We analyzed data from ~100,000 unrelated European UK Biobank participants without T2D and not taking lipid-lowering medications. T2D subtypes were characterized using five polygenic scores denoting three forms of insulin resistance (lipodystrophy, obesity, and impaired lipid/hepatic metabolism) and two subtypes of insulin secretion (beta-cell dysfunction and impaired proinsulin synthesis). Nuclear magnetic resonance profiles of 249 plasma metabolites on the Nightingale platform were tested for association with T2D subtypes using linear regression adjusted for age, sex, batch, and ancestry-derived principal components; P<0.0002 was considered significant. Independent validation was conducted in two independent cohorts, including 720 from the ANTORCHA cohort. In general, the T2D subtypes driven by insulin resistance were characterized by alterations in lipid and lipoproteins, while the impaired insulin secretion subtypes showed aberrant plasma amino acid levels. The lipodystrophy cluster showed the most distinct molecular signature, with higher concentrations of extremely large, very large, and large VLDL particles which were enriched by triglycerides and phospholipids, and lower concentrations of HDL. The beta-cell dysfunction cluster was characterized by higher concentrations of amino acids (alanine, valine, leucine, and tyrosine). These associations were broadly consistent after adjusting for BMI, and the pattern of alterations in lipid metabolites was partially replicated in the ANTORCHA cohort. We identified specific metabolic signatures related to T2D genetic clusters before T2D onset, offering further characterization of the putative underlying pathways.

Disclosure

M.Sevilla: None. I.Lamiquiz-moneo: None. K.Smith: None. M.Canyelles: None. J.C.Florez: Consultant; AstraZeneca, Novo Nordisk, Other Relationship; AstraZeneca, Merck & Co., Inc. A.Manning: None. F.Civeira: None. J.Merino: None. M.Udler: None.

Funding

American Diabetes Association (9-22-PDFPM-04 to M.S.)
1479-P: Targeted Exome Sequencing for Long-Term Efficacy and Weight Loss of Dulaglutide in Type 2 Diabetes
Authors: AN KIM YE , HYUN SEO JE
Published: June 2023

Introduction: There are individual differences in glucose lowering effect and weight reduction of dulaglutide, long-acting glucagon-like peptide-1 (GLP-1) receptor agonist. It is expected that genetic variations in the mechanism of action of drugs are involved in treatment response to drugs. This study aims to investigate genetic variants associated with long-term efficacy and weight reduction of dulaglutide using targeted next-generation sequencing.

Methods: We recruited 77 patients those who were treated with dulaglutide at least one year after switching from DPP-4 inhibitors (±basal insulin) due to uncontrolled type 2 diabetes (HbA1c ≥8.0%) at Korean VHS medical center between September 2018 and October 2019, and followed up until March 2021. The responder was defined by ≥1.0% HbA1c reduction at 24 weeks and achievement of HbA1c ≤7.5% at 52 weeks. We designed targeted exome panel based on the mechanism of drug action, and candidate genetic variants included known GLP-1 response related genes (n=10), gastric emptying related genes (n=18), pancreatic insulin secretion related genes (n=25). At the same time, we also performed whole exome sequencing.

Results: During follow-up period of median 2.5±1.3 years, HbA1c was 9.7±1.3% at baseline and reduced to 8.2±1.5% at 6 months, and maintained thereafter up to 4 years. Glycemic response was associated with GNB3, SPARC, and COL4A1 genes. Weight loss (n=13) was more frequently observed in patients with minor G alleles of COL4A1 gene (OR 2.516, 95% CI 1.013, 6.249, p=0.047). Glycemic effectiveness of dulaglutide therapy is associated with genetic variants (OR 2.106, 95% CI 1.358, 3.265, p=0.001) as well as baseline HbA1c (OR 1.682, 95% CI 1.067, 2.650, p=0.025).

Conclusion: The glucose lowering effect of dulaglutide, which exempts some patients from insulin therapy, has been associated with GNB3, SPARC, and COL4A1 variants. Polymorphisms in COL4A1 gene was associated with weight loss, although further studies are needed for validation.

Disclosure

Y.Kim: None. J.Seo: None.

Funding

VHS Medical Center (VHSMC20026)
1480-P: Mitochondrial Haplogroup H Is Protective against Type 2 Diabetes in Arabs from Gulf Region
Authors: DASHTI MOHAMMED H. , ALI NASER , ALSALEH HUSSAIN , NIZAM RASHEEBA , ALMULLA FAHD , THANGAVEL ALPHONSE T.
Published: June 2023

Background: Mitochondrial dysfunction is implicated in the pathogenesis of type 2 diabetes (T2D) via impaired glucose-stimulated insulin secretion in pancreatic beta cells and decreased oxidative phosphorylation in insulin target tissues. Several global studies have been performed to delineate the genetic associations of mitochondrial DNA (mtDNA) haplogroups and variants with T2D incidence. Maternal haplogroups F, D, M9 and N9a and a rare variant (mtDNA 3243 A>G) and a common variant (mtDNA 16189 T>C) were associated with increased risk of T2D in different populations. It is worth noting that some of these proposed associations were not consistent across populations. Since the Gulf Cooperation Council (GCC) countries are marked by high prevalence of T2D, we aim to study association of mitochondrial haplogroups and variants in Arabs from GCC region.

Methods: We examined mitochondrial haplogroups and variants in 1,112 Kuwaiti and Qatari native individuals using whole exome sequencing data. The cohort was divided into T2D cases (685) and non-T2D controls (427).

Results: The association tests indicated that individuals with haplogroup H have a protective effect against T2D with a suggestive significance [odds ratio (OR) = 0.65; P = 0.022]. The haplogroup H association remained significant even after adjusting for age, sex, and body mass index (BMI) (OR= 0.607; P= 0.021). We also identified mtDNA variants with suggestive significance of association (adjusting for covariates) with T2D.

Conclusion: The study demonstrates that maternal H haplogroup, which we previously identified as protective towards obesity in Kuwaiti Arabs, is a protective haplogroup for T2D in Arabs from GCC. Further, the mtDNA variants delineated as associated with T2D are from genes involved in cell energy production.

Disclosure

M.H.Dashti: None. N.Ali: None. H.Alsaleh: None. R.Nizam: None. F.Almulla: None. A.T.Thangavel: None.
1484-P: CD57+CD8+T Cells Exhibit Distinct Features in T1D Patients with Partial Remission Phase
Authors: LI XIA , ZHONG TING , TANG RONG , LI XINYU , KANG LEI
Published: June 2023

Partial remission (PR) in type 1 diabetes (T1D) is accompanied by downregulation of the immune response. The CD8+ CD57+ T cells, termed effector memory cells, is expanded in several immune-mediated diseases, but their changes in the PR phase are unclear. Combined with flow cytometry and bioinformatics analysis, we found that CD8+ CD57+ T cells had strong cytotoxic functions and transcriptional heterogeneity, and that the proportion of CD8+ CD57+ T cells increased in new-onset patients, decreased in patients during PR and then repleted again after the end of PR. These findings suggests that CD8+ CD57+ T cells might have potential roles in immune modulation during the PR stage and might serve as a therapeutic target.

Disclosure

X.Li: None. T.Zhong: None. R.Tang: None. X.Li: None. L.Kang: None.
1489-P: iPLA2gamma as a Mediator of Lipid-Induced Metabolic Inflammation and Insulin Resistance
Authors: LEE MYUNG-SHIK , KANG HYEREEN
Published: June 2023

We have reported that bromenol lactone (BEL) improves metabolic profile. Here, we studied effect of BEL and its target iPLA2 in inflammasome which is a crucial in insulin resistance and metabolic inflammation. BEL inhibited inflammasome by LPS+palmitic acid (PA). BEL also ameliorated mitochondrial ROS and mitochondrial potential loss by LPS+PA, explaining reduced inflammasome. BEL administration in vivo also reduced metabolic inflammation and inflammasome. iPLA2gamma-KO but not iPLA2beta-KO macrophages showed reduced inflammasome by LPS+PA. Mitochondrial ROS and mitochondrial potential loss by LPS+PA were markedly reduced by iPLA2gamma KO. Cardiolipin content in macrophages was reduced by LPS+PA, which was recovered by BEL or myxothiazol, an inhibitor of mitochondrial complex bc1. Cardiolipin loss by LPS+PA was also ameliorated by iPLA2gamma KO. Cardiolipin liposome or expression of CRLS1, a gene for rate-limiting step of cardiolipin biosynthesis, reduced inflammasome by LPS+PA, while CRLS1 siRNA aggravated, suggesting that reduced cardiolipin content is critical in inflammasome by LPS+PA. iPLA2gamma-KO mice were protected from diet-induced insulin resistance, associated with reduced inflammasome and metabolic inflammation. These results suggest that initial reduction of cardiolipin content by PA-induced ROS probably due to removal of oxidized cardiolipin by iPLA2gamma might induce further mitochondrial ROS accumulation likely due to compromised mitochondrial complex activity, which would eventually lead to massive mitochondrial ROS production, marked loss of mitochondrial cardiolipin, profound mitochondrial dysfunction, and finally metabolic inflammation with lipid-induced insulin resistance, through a feed-forward mechanism. Replenishment of cardiolipin could a novel modality for treatment of diet-induced insulin resistance through recovery of mitochondrial function and amelioration of lipid-mediated inflammasome or metabolic inflammation.

Disclosure

M.Lee: None. H.Kang: None.

Funding

National Research Foundation of Korea (2019R1A2C3002924)
1494-P: ILV-001, a Highly Promising Therapeutic Agent for Islet Transplantation
Authors: LANGLOIS ALLAN , GRABARZ ANASTASIA , PINGET MICHEL , BOUZAKRI KARIM
Published: June 2023

Introduction: Our team has shown a bimodal effect on β-cells of muscle-secreted myokines from normal or insulin-resistant human skeletal muscle. We identified ILV-001, a component of the muscle secretome regulated by muscle fiber type and physical exercise, moreover naturally present in the extracellular matrix of the islet niche. Thus, we aimed at investigating the therapeutic potential of ILV-001 in protecting β-cell function and survival during islet transplantation.

Methods: In vitro: Rat islets were incubated 24h ± ILV-001 (1µg/mL). Islet survival was assessed by TUNEL assay ± cytomix. Islet function was evaluated using GSIS test. In vivo: 10000 IEQ/kg ± ILV-001 were injected intraportaly in diabetic syngeneic rats. For 3 months body weight gain, glycaemia, c-peptidemia and graft function (IPGTT) were followed. Inflammation was evaluated titrating plasmatic α2-macroglobulin. Histology was performed on grafted islets.

Results: In vitro: ILV-001 improves islet function and survival and potentiates insulin secretion after GSIS test. In vivo: ILV-001 improves graft function in terms of glycaemia (p<0.001) and c-peptidaemia (p<0.01) and decreases exogenous insulin intake requirements. ILV-001 reduced inflammation 24h post graft with a lower plasmatic α2-macroglobulin versus control with respectively 459±70 versus 903±191 µg/mL (p<0.05). Finally, histology showed a preservation of insulin positive cells with ILV-001 versus control at the end of study (69±3% versus 39±3% of β-cells/islet, p< 0.001).

Conclusion: ILV-001 is a highly promising candidate for the achievement of a functional cure in T1D thanks to potent β-cell preservation and obtaining long term graft maintenance following islet transplant.

Disclosure

A.Langlois: None. A.Grabarz: Stock/Shareholder; Ilonov. M.Pinget: Consultant; Novo Nordisk, Stock/Shareholder; ILONOV. K.Bouzakri: Consultant; Adocia, Stock/Shareholder; ILONOV.
1499-P: Adipocyte Development from Mesenchymal Progenitor Cells Differ between Subjects with Normal Glucose Tolerance or Type 2 Diabetes
Authors: CORVERA SILVIA , DESOUZA TIFFANY A. , ZIEGLER RACHEL N. , ROSANO NINA , THOMPSON MICHAEL J.
Published: June 2023

Subcutaneous adipose tissue protects from T2D by sequestering lipids and preventing lipotoxicity and insulin resistance. Adipose depots are maintained throughout the lifetime by the formation of new adipocytes from mesenchymal progenitor cells that reside within the tissue. In previous studies, we have found that mesenchymal progenitor cells from human adipose tissue can be expanded with little loss of multipotency by culturing tissue explants in 3-dimensional hydrogels under pro-angiogenic conditions. Mesenchymal progenitor cells obtained in this manner can be induced to differentiate into multiple adipocyte subtypes, including beige adipocytes characterized by their induction of UCP1 upon cAMP elevation. Using this approach, we explored whether mesenchymal progenitor cells from the subcutaneous abdominal (ABD) and gluteal (GLU) depots of subjects with normal glucose tolerance (NGT) or T2D would differ in their capacity to differentiate into adipocyte subtypes. Results from n=12 subjects (6 with NGT and 6 with T2D) revealed no significant differences between depots or glycemic states in the number of mesenchymal progenitor cells that can be expanded, in their proliferative rate upon subsequent passaging, or in their capacity to differentiate into either white or beige adipocytes. However, we found that cells from either the ABD or GLUT depot from NGT subjects displayed substantial spontaneous adipocyte differentiation even without adipogenic induction, but cells from subjects with T2D did not. This difference was highly significant, and potentially reflects a diminished capacity of mesenchymal progenitor cells to maintain subcutaneous adipose depots in-vivo in subjects with T2D. Further transcriptomic and epigenomic analyses of expanded progenitor cells, currently underway, has the potential to reveal cellular mechanisms of impaired spontaneous adipocyte differentiation in subjects with Type 2 Diabetes.

Disclosure

S.Corvera: None. T.A.Desouza: None. R.N.Ziegler: None. N.Rosano: None. M.J.Thompson: None.
150-LB: Evaluation of a Diabetes Screening Clinical Decision Support Tool
Authors: TSENG EVA , MATHIOUDAKIS NESTORAS , MARUTHUR NISA M. , YEH HSIN-CHIEH , STEIN ARIELLA
Published: June 2023

As part of a health system diabetes prevention initiative, we implemented and evaluated if an EHR clinical decision support tool improves diabetes screening rates. The EHR clinical decision support tool, implemented in 7/2021, alerts clinicians when a patient is due for diabetes screening based on USPSTF 2021 guidelines (BMI ≥25 kg/m² and age 35-70 years). The primary outcome was the monthly screening lab order rate, % patients eligible for screening who received a lab order during their primary care visit in that month. The secondary outcome was the monthly screening lab completion rate, % patients eligible for screening who completed a screening lab test during their primary care visit in that month. We used logistic regression to evaluate changes in outcomes from baseline to post-implementation periods. In a tertiary health system, 16,431 eligible primary care patients were seen between 7/2020-12/2022. At baseline (7/2020-7/14/21), screening lab order and completion rates were 65% and 58%, respectively. Rates increased significantly in the post-implementation period (1/2022-12/2022) compared to baseline (lab orders: OR 1.7, p<0.001, completion: OR 1.8, p<0.001). Our study demonstrates an EHR clinical decision support tool, in the context of a system-wide initiative, can successfully improve diabetes screening rates. These findings support other healthcare organizations to explore clinical support tools for diabetes screening.

Disclosure

E. Tseng: None. N. Mathioudakis: None. N. M. Maruthur: Other Relationship; Johns Hopkins HealthCare Solutions. H. Yeh: None. A. Stein: None.

Funding

National Institutes of Health (K23DK118205)
1502-P: Adipose Tissue Protein Response and Insulin Sensitivity in Obesity
Authors: LYTLE KELLI , JENSEN MICHAEL D.
Published: June 2023

Dysregulation of adipose tissue (AT) lipolysis, a hallmark of obesity and type 2 diabetes, results in elevated postabsorptive and postprandial plasma free fatty acid (FFA) concentrations. This is thought to be due to adipose insulin resistance with regards to anti-lipolysis effects. Alterations in intracellular adipocyte pathways and/or proteins that mediate this phenomenon in humans are poorly understood. To test the hypothesis that impaired insulin signaling is associated with adipose insulin resistance measured whole body insulin sensitivity (the insulin concentration that suppresses palmitate flux by 50% (IC50 FFA)) in 12 lean, 7 lower body obese and 15 upper body obese (n=15) volunteers using a single step hyperinsulinemic-euglycemic clamp. We also measured adipose pAkt/Akt (a measure of insulin signaling) and hormone sensitive lipase (pHSL/HSL) (a measure of lipolysis protein regulation) in biopsies of abdominal and thigh adipose obtained before and during the insulin clamp were measured. Contrary to our hypothesis, there was a positive relationship between IC50 FFA and insulin clamp fold change of pAkt/Akt in thigh samples (ρ = 0.38, p <0.05) and no relationship for abdominal adipose samples. There was good correlation between abdominal and thigh adipose samples in the fractional change in pAkt/Akt in response to insulin clamp (ρ= 0.49, p < 0.01). IC50 FFA was correlated to fractional decrease in HSL phosphorylation in both abdominal (r = 0.36, p< 0.05) and thigh (r = 0.41, p <0.05) Surprisingly, fold changes of pAKT/AKT in response to insulin clamp were positively correlated to fold change of pHSL/HSL in abdominal adipose tissue (ρ= 0.41, p < 0.05) but not thigh samples. In conclusion we found that insulin resistance in adipose is not related to canonical insulin signaling responses but is related to lipase responses.

Disclosure

K.Lytle: None. M.D.Jensen: Other Relationship; Novo Nordisk, Elsevier.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (DK40484)
1503-P: Insulin Regulates Expression and Secretion of Exosomal MicroRNAs in Adipocytes
Authors: LINO MARSEL , PAN HUI , DREYFUSS JONATHAN , RONALD KAHN C.
Published: June 2023

Transfer of regulatory molecules, such as microRNAs (miRNAs), via small extracellular vesicles (sEVs) called exosomes represents a newly recognized mode of inter-organ communication that provides an important mechanism of metabolic regulation. We have previously shown that adipose tissue is a major contributor to the pool of circulating exosomal miRNAs and that these adipose-derived exosomal miRNAs can be taken up by target tissues and suppress gene expression. We have also shown that biogenesis, secretion, and exosomal cargo sorting is a highly regulated process and that miRNAs contain 4-8 nucleotide motifs which contribute to exosomal secretion. Several exosomal miRNAs have been linked to obesity and diabetes, yet their regulation by physiological stimuli such as insulin remains unknown. To identify the role of insulin in regulation of adipose miRNAs and their secretion in exosomes, we performed small RNA-seq on exosomes isolated from differentiated 3T3-L1 cells with and without insulin stimulation. We find that out of the 460 miRNAs detected, 39 were up- and 75 were down-regulated in exosomes in response to insulin, whereas only 14 were up- and 39 were down-regulated in cells. In some cases, exosomal secretion correlated with cellular expression of the miRNA. More interestingly, 103 of the 114 miRNAs (90.3%) that were regulated in exosomes had no significant change at the cellular level or even a change in the opposite direction, demonstrating insulin’s ability to regulate miRNA exosomal secretion independent of cellular level. These insulin-regulated exosomal miRNAs included members of the let-7 family, which have known functions in adipogenesis, as well miRNAs predicted to target mRNAs of molecules involved in fatty acid biosynthesis and insulin signaling. Thus, insulin can independently regulate miRNA expression and secretion in adipocyte-derived exosomes. These can serve as adipokines and create a novel mechanism for regulation of cell-cell and inter-organ communication.

Disclosure

M.Lino: None. H.Pan: None. J.Dreyfuss: None. C.Kahn: None.

Funding

National Institutes of Health (5R01DK082659)
1505-P: CD44 Knockdown in Human Adipocytes—Effect on Adipocyte Proliferation and Differentiation
Authors: CHEN HENRY , SAINI NATESH R. , AYHAN EKREM M. , MCLAUGHLIN TRACEY
Published: June 2023

Introduction: eGWAS implicates the immune-cell receptor CD44 as the top candidate gene in the molecular pathogenesis of T2D1. We have shown that in human adipose tissue, CD44 expression is associated with inflammatory gene expression, M1 macrophage phenotype, and systemic insulin resistance2. Here we sought to determine whether CD44 directly impairs adipocyte function via siRNA knockdown in human preadipocytes with quantification of proliferation, differentiation, and gene expression.

Methods: Abdominal subcutaneous adipose tissue was harvested from five healthy nondiabetic obese individuals during bariatric surgery. Preadipocytes were isolated via collagenase digestion and seeded at 1×10^4 cells/well and treated with siRNA-CD44 or mock condition (control) using siRNA Maxi Transfection Reagents (Invitrogen). Cell proliferation was assayed by MTS (Promega) on Days 1, 2, 3 post transfection. Differentiation was induced at confluence (as described3), and cells were harvested at days 3, 6, 12 after confluence for gene expression and at day 12 for oil red O staining (total lipid uptake) and immunofluorescence microscopy (% differentiation = bodipy/dapi*100).

Results: CD44 knockdown decreased preadipocyte proliferation and increased adipocyte differentiation and lipid uptake.

Conclusion: CD44 may contribute to human insulin resistance by impairing adipocyte differentiation and fat storage.

Disclosure

H.Chen: None. N.R.Saini: None. E.M.Ayhan: None. T.Mclaughlin: Board Member; January, Inc., Research Support; Merck & Co., Inc., Stock/Shareholder; Eiger Bio.

Funding

National Institutes of Health (1R21AI159024-01A1)
1507-P: Carnosic Acid–Induced Browning in 3T3-L1 Adipocytes Is Dependent on AMPK Activation
Authors: VLAVCHESKI FILIP , TSAKIRIDIS NICOLE , GIACCA ADRIA , TSIANI EVANGELIA
Published: June 2023

Background: Increased adiposity has long been associated with insulin resistance and adipose tissue plays a crucial role in regulating metabolic homeostasis, as its dysfunction in obesity leads to insulin resistance and type 2 diabetes (T2D). The primary function of white adipose tissue (WAT) is to store energy as lipids while brown adipose tissue (BAT) regulates thermogenesis by dissipating energy in a form of heat. The process of browning involves transdifferention of WAT into brown-like or beige adipocytes, which exhibit the same functional properties as BAT. Browning of WAT is an attractive approach against obesity and insulin resistance. In addition, evidence indicate that activation of the energy sensor AMP-activated protein kinase (AMPK) could counteract insulin resistance. The aim of this study is to examine if carnosic acid (CA), induces browning via activation of AMPK in 3T3-L1 white adipocytes.

Material and methods: Cell morphology, lipid accumulation, mitochondrial density, and browning markers such as uncoupling protein-1 (UCP-1) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) levels were assessed using Cytation5 microscope, Oil-O-Red (ORO), MitoTracker Red, immunoblotting and immunocytochemistry.

Results: Microscopic investigation revealed that CA reduced the size and number of lipid droplets in the cells, giving a rise to a brown-like phenotype. The reduction of lipid accumulation was also confirmed by ORO stain. Next, CA increased mitochondrial density and protein expression of UCP-1 and PGC-1-α in 3T3-L1 adipocytes. Most importantly, pre-treatment with compound C, prevented the CA-induced reduction in lipid accumulation, and mitochondrial density and blocked the CA-induced increase in UCP-1 and PGC-1 expression.

Conclusion: This study demonstrates that CA has a pronounced potential in stimulating browning of adipocytes via AMPK-dependent mechanism. Future in vivo studies are required to fully examine the effects of CA.

Disclosure

F.Vlavcheski: None. N.Tsakiridis: None. A.Giacca: None. E.Tsiani: None.

Funding

Natural Science and Engineering Research Council of Canada (RGPIN-2018-06666)
1509-P: Global Metabolomic Profiling and the Pathobiology of Prediabetes and Type 2 Diabetes
Authors: DUBEY DHRUV , DUTTA TUMPA , NUNEZ LOPEZ YURY O. , GARDELL STEPHEN J. , PRATLEY RICHARD E.
Published: June 2023

Introduction: Metabolomics has provided valuable insights into metabolic alterations associated with diabetes. However, prior studies profiled only a small subset of metabolites that was possible with the contemporaneous technology. We aimed to reassess and extend the current knowledge by implementing comprehensive LC-MS/MS metabolomic analyses.

Methods: Untargeted metabolomic analysis was performed using serum samples from people with normal glucose tolerance, prediabetes, and type 2 diabetes (n=30, balanced ORIGINS cohort subset, NCT02226640), at baseline and 2 hours (2h) after an oral glucose tolerance test (OGTT). Differential expression (MetaboAnalyst) and coexpression network (WGCNA) analyses were implemented. Random Forest classification was used to further assess variable importance.

Results: A total of 697 known metabolites were detected in more than 80% of the samples. This represents a significant increase in the number of detected circulating metabolites compared to previous studies in diabetes. WGCNA identified modules of correlated metabolites that associated with glucose tolerance at baseline and 2h. The top module for each timepoint was enriched in metabolites that significantly changed in response to the glucose challenge and highlighted an underappreciated role of glyoxylate and dicarboxylate metabolism in early stages of diabetes evolution. Elevation of hexoses and bile acids, and downregulation of amino acids, lipids, and free fatty acids were demonstrated after the glucose challenge. Random forest classification further unveiled the biomarker potential of baseline levels of aminoadipic and methyluric acids.

Conclusions: Comprehensive profiling of serum metabolites in humans underscored the role of carbohydrate metabolism, the citric acid and urea cycles, suppression of lipolysis, ketogenesis, and proteolysis in response to a glucose challenge. Potential biomarkers of early diabetes development and progression were identified.

Disclosure

D.Dubey: None. T.Dutta: None. Y.O.Nunez lopez: None. S.J.Gardell: None. R.E.Pratley: Other Relationship; Bayer Inc., Corcept Therapeutics, Dexcom, Inc., Gasherbrum Bio, Inc., Hanmi Pharm. Co., Ltd., Hengrui (USA) Ltd., Merck Sharp & Dohme Corp., Novo Nordisk, Pfizer Inc., Rivus Pharmaceuticals Inc., Sanofi, Scohia Pharma Inc., Sun Pharmaceutical Industries Ltd.

Funding

AdventHealth Translational Research Institute
151-OR: Social Determinants of Health Predict Diabetic Foot Infection Development
Authors: SCHMIDT BRIAN M. , BURANT AARON , BAKER NICOLE , KATONA AIMEE , MARTIN CATHERINE , HOLMES CRYSTAL M. , BUSUI RODICA
Published: June 2023

The objective was to identify social determinants of health (SDOH) associated with development of diabetic foot infection using the CDC Healthy People Framework at a tertiary care center. Targeted interrogation of structured and unstructured data using novel electronic medical record search engines was used to analyze patient encounters in individuals with diabetes and a concomitant diabetic foot complication during a twenty-year period (2001-2021). Among ~ 200 million encounters from people with diabetic foot complications, 8351 developed diabetic foot ulcers (DFU), and 1671 suffered a DFU infection. The risk of infection development in people with a DFU was assessed with the neighborhood disadvantaged index score from over 200 million separate patient encounters. The neighborhood disadvantaged index based on available geolocation data, provides a unitless value to describe the relative socioeconomic background of an individual as determined by the proportion (%) of non-Hispanic black, proportion (%) of female headed families with children, and the proportion of households (%) with public assistance income or food stamps in a defined area. The average disadvantaged index score for the DFU population was 0.06 and was comparable to the state of Michigan's average disadvantaged index of 0.05. In those persons who developed DFU infection, the index score averaged 0.13, 2.2x higher than the DFU population (p<0.05). Additionally, divorced individuals represented 2% of all individuals with DFU but accounted for 5% of those who developed DFU infection. This was disproportionate to other marriage statuses. These data strongly support the need to incorporate SDOH into updated DFU standard of care guidelines. Moreover, we clearly demonstrate that SDOH, more specifically geolocation data, can be used to identify individuals who are more likely to develop DFU infection. Thus, it is essential that SDOH are included in patient risk stratification to prevent severe diabetic foot complications.

Disclosure

B.M.Schmidt: None. A.Burant: None. N.Baker: None. A.Katona: None. C.Martin: Advisory Panel; Nevro Corp. C.M.Holmes: None. R.Busui: Board Member; American Diabetes Association, Consultant; Averitas Pharma, Inc., Lexicon Pharmaceuticals, Inc., Nevro Corp., Novo Nordisk, Roche Diagnostics, Procter & Gamble, Research Support; Novo Nordisk, Medtronic, National Institutes of Health.

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (1K23DK131261-01A1, 5U01DK119083-05)
1511-P: Identifying How Endothelial Protease-Activated Receptors Control Insulin Signaling—Implications for Diabetes
Authors: RAJALA RAHUL , GRIFFIN COURTNEY
Published: June 2023

Endothelial cell (EC) dysfunction occurs in diabetes. Thrombin, a circulating serine protease with increased activity in diabetics, signals through protease-activated receptors 1 and 4 (PAR1/PAR4). To determine EC-specific roles of PARs in diabetes, we generated Par1fl//fl; Par4fl/fl; iCdh5 (PAC)-CreERT2 (Par1/4dECko) mice and challenged them with streptozotocin (STZ) to induce hyperglycemia. STZ-treated Par1/4dECko mice had reduced blood glucose levels, weighed significantly more, and lost less abdominal fat than control littermates. Neither Par4ECko nor Par1ECko mice phenocopied Par1/4ECko mutants, suggesting that loss of both thrombin receptors is required to drive these phenotypes. Notably, STZ-treated Par1/4dECko mice showed comparable insulin levels to their STZ-treated littermates, suggesting mutant mice had heightened insulin sensitivity, which was verified by insulin/glucose tolerance testing. Using primary human ECs that express PAR1 but not PAR4, we found that PAR1/4 depletion increased basal insulin receptor (IR) activity as measured by the uptake of a glucose-analog. PAR1/4-depleted ECs also showed increased insulin receptor Type-A (IR-A) spliceform expression, which has high insulin-independent basal activity. Conversely, treatment of ECs with a PAR1 ligand upregulated the insulin-dependent IR Type-B (IR-B) spliceform, suggesting that endothelial PAR1/4 can modulate IR splicing/activity. Additionally, we found that ECs in many wildtype mouse organs, including skeletal muscle, predominantly express IR-B in vivo. Therefore, a switch to IR-A expression in Par1/4dECko mice may enhance endothelial IR activity. IR activity in ECs regulates insulin transport from the bloodstream to the parenchyma. We propose that loss of EC PAR1/4 elevates whole-body insulin sensitivity by increasing IR splicing/activity and subsequent transcytosis to the parenchyma. Thus, EC PAR1/4 modulation may hold promise for treating diabetes.

Disclosure

R.Rajala: None. C.Griffin: None.

Funding

American Heart Association (23PRE1014240); National Institutes of Health (HL144605)
1514-P: Insulin Sensitivity Initially Worsens but Later Improves with Aging in C57BL/6N Mice
Authors: KONDO HIROYA , ONO HIRAKU , YOKOTE KOUTARO
Published: June 2023

Objective: Aging is believed to induce insulin resistance in humans. However, when and how insulin sensitivity changes with aging remain unclear in both humans and mice.

Methods: Groups of C57BL/6N mice at 9-15 weeks (young), 34-67 weeks (one-year-old) and 107-121 weeks (two-year-old) of age underwent hyperinsulinemic-euglycemic clamp studies with somatostatin infusion under awake and non-restrained conditions.

Results: The glucose infusion rates for maintaining euglycemia were 17.11±2.94, 5.58±1.28 and 25.30±4.42 mg/kg/min in young, one-year-old and two-year-old mice, respectively. Thus, compared with young mice, one-year-old mice exhibited the expected insulin resistance. In contrast, the insulin sensitivity of two-year-old mice showed significant improvement. These age-related changes were mainly observed in glucose uptake into adipose tissue and skeletal muscle. Epididymal fat weight and hepatic triglyceride levels were highest in one-year-old mice, while being similar in young and two-year-old mice.

Conclusions: Our observations indicate that, in mice, insulin resistance appears at one year of age but subsequently improves markedly. These alterations in insulin sensitivity are attributable to changes in visceral fat accumulations and age-related factors.

Disclosure

H.Kondo: None. H.Ono: None. K.Yokote: None.

Funding

Japan Society for the Promotion of Science (15K09398, 18K08502, 20H00524); Japan Agency for Medical Research and Development (17GM5010002H0001, 18GM5010002H0002, 19GM5010002H0003, 20GM5010002H0004)
1516-P: Free Fatty Acid and Amino Acid Predictors of Response to Metformin in Polycystic Ovary Syndrome
Authors: CHANG ALICE Y. , ASOKAN ANEESH K. , SAKRIKAR DHANANJAY , LALIA ANTIGONI , LANZA IAN R. , PETTERSON MAI , SREEKUMARAN NAIR K.
Published: June 2023

Metformin is one of the most widely used antidiabetic drugs and is also effectively used in treating women with polycystic ovary syndrome (PCOS). Our global objective is to separate women with PCOS into subtypes by their response to metformin. This pilot study aims to determine which free fatty acids and amino acids metabolites predict response to metformin as categorized by changes in insulin sensitivity and testosterone concentrations after three months of metformin therapy. We recruited 42 participants with PCOS aged between 18-50 years. Participants were randomly categorized into metformin (n= 29; 32.41 ± 7.4 years) and placebo groups (n=13; 32.15 ± 5.65 years). The Metformin group was challenged with three months of metformin titrated to at least 1500 mg daily. Body weights decreased significantly in the metformin treatment group from 98.55 ± 22.76 to 97.27 ± 23.14 (p-value=0.01) but did not change in the placebo group. Fasting plasma glucose decreased only in the metformin group from 89.25 ± 9.12 to 86.37 ± 9.53. Testosterone levels decreased in the metformin-treated group after 12 weeks from 29.0 (18.5 - 35.5) to 23.0 (15.5 - 32.5), but no significant change was observed in the placebo group from 28.0 (20.0 - 43.0) to 27.0 (21.5 -49.0). However, we did not observe a statistically significant change in insulin sensitivity values in PCOS and placebo groups. Linear regression analysis was performed to check the predictive power of those associated metabolites with delta values of testosterone and insulin sensitivity. Our results showed that changes in insulin sensitivity and testosterone levels after metformin treatment could be significantly predicted by using concentrations of metabolites (Fig.1).

Disclosure

A.Y. Chang: None. A.K. Asokan: None. D. Sakrikar: Employee; The Binding Site. A. Lalia: None. I.R. Lanza: None. M. Petterson: None. K. Nair: None.

Funding

National Institutes of Health (UL1TR000135)