Browsing by Author "Sims, Emily K."
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Item 100 years of insulin: celebrating the past, present and future of diabetes therapy(Springer Nature, 2021) Sims, Emily K.; Carr, Alice L.J.; Oram, Richard A.; DiMeglio, Linda A.; Evans-Molina, Carmella; Pediatrics, School of MedicineThe year 2021 marks the centennial of Banting and Best's landmark description of the discovery of insulin. This discovery and insulin's rapid clinical deployment effectively transformed type 1 diabetes from a fatal diagnosis into a medically manageable chronic condition. In this Review, we describe key accomplishments leading to and building on this momentous occasion in medical history, including advancements in our understanding of the role of insulin in diabetes pathophysiology, the molecular characterization of insulin and the clinical use of insulin. Achievements are also viewed through the lens of patients impacted by insulin therapy and the evolution of insulin pharmacokinetics and delivery over the past 100 years. Finally, we reflect on the future of insulin therapy and diabetes treatment, as well as challenges to be addressed moving forward, so that the full potential of this transformative discovery may be realized.Item A proteomic meta-analysis refinement of plasma extracellular vesicles(Springer Nature, 2023-11-28) Vallejo, Milene C.; Sarkar, Soumyadeep; Elliott, Emily C.; Henry, Hayden R.; Powell, Samantha M.; Diaz Ludovico, Ivo; You, Youngki; Huang, Fei; Payne, Samuel H.; Ramanadham, Sasanka; Sims, Emily K.; Metz, Thomas O.; Mirmira, Raghavendra G.; Nakayasu, Ernesto S.; Pediatrics, School of MedicineExtracellular vesicles play major roles in cell-to-cell communication and are excellent biomarker candidates. However, studying plasma extracellular vesicles is challenging due to contaminants. Here, we performed a proteomics meta-analysis of public data to refine the plasma EV composition by separating EV proteins and contaminants into different clusters. We obtained two clusters with a total of 1717 proteins that were depleted of known contaminants and enriched in EV markers with independently validated 71% true-positive. These clusters had 133 clusters of differentiation (CD) antigens and were enriched with proteins from cell-to-cell communication and signaling. We compared our data with the proteins deposited in PeptideAtlas, making our refined EV protein list a resource for mechanistic and biomarker studies. As a use case example for this resource, we validated the type 1 diabetes biomarker proplatelet basic protein in EVs and showed that it regulates apoptosis of β cells and macrophages, two key players in the disease development. Our approach provides a refinement of the EV composition and a resource for the scientific community.Item Abnormalities in proinsulin processing in islets from individuals with longstanding T1D(Elsevier, 2019-11) Sims, Emily K.; Syed, Farooq; Nyalwidhe, Julius; Bahnson, Henry T.; Haataja, Leena; Speake, Cate; Morris, Margaret A.; Balamurugan, Appakalai N.; Mirmira, Raghavendra G.; Nadler, Jerry; Mastracci, Teresa L.; Arvan, Peter; Greenbaum, Carla J.; Evans-Molina, Carmella; Pediatrics, School of MedicineWe recently described the persistence of detectable serum proinsulin in a large majority of individuals with longstanding type 1 diabetes (T1D), including individuals with undetectable serum C-peptide. Here, we sought to further explore the mechanistic etiologies of persistent proinsulin secretion in T1D at the level of the islet, using tissues obtained from human donors. Immunostaining for proinsulin and insulin was performed on human pancreatic sections from the Network for Pancreatic Organ Donors with Diabetes (nPOD) collection (n = 24). Differential proinsulin processing enzyme expression was analyzed using mass spectrometry analysis of human islets isolated from pancreatic sections with laser capture microdissection (n = 6). Proinsulin processing enzyme mRNA levels were assessed using quantitative real-time PCR in isolated human islets (n = 10) treated with or without inflammatory cytokines. Compared to nondiabetic controls, immunostaining among a subset (4/9) of insulin positive T1D donor islets revealed increased numbers of cells with proinsulin-enriched, insulin-poor staining. T1D donor islets also exhibited increased proinsulin fluorescence intensity relative to insulin fluorescence intensity. Laser capture microdissection followed by mass spectrometry revealed reductions in the proinsulin processing enzymes prohormone convertase 1/3 (PC1/3) and carboxypeptidase E (CPE) in T1D donors. Twenty-four hour treatment of human islets with inflammatory cytokines reduced mRNA expression of the processing enzymes PC1/3, PC2, and CPE. Taken together, these data provide new mechanistic insight into altered proinsulin processing in long-duration T1D and suggest that reduced β cell prohormone processing is associated with proinflammatory cytokine-induced reductions in proinsulin processing enzyme expression.Item Altered β-Cell Prohormone Processing and Secretion in Type 1 Diabetes(American Diabetes Association, 2021) Rodriguez-Calvo, Teresa; Chen, Yi-Chun; Verchere, C. Bruce; Haataja, Leena; Arvan, Peter; Leete, Pia; Richardson, Sarah J.; Morgan, Noel G.; Qian, Wei-Jun; Pugliese, Alberto; Atkinson, Mark; Evans-Molina, Carmella; Sims, Emily K.; Pediatrics, School of MedicineAnalysis of data from clinical cohorts, and more recently from human pancreatic tissue, indicates that reduced prohormone processing is an early and persistent finding in type 1 diabetes. In this article, we review the current state of knowledge regarding alterations in islet prohormone expression and processing in type 1 diabetes and consider the clinical impact of these findings. Lingering questions, including pathologic etiologies and consequences of altered prohormone expression and secretion in type 1 diabetes, and the natural history of circulating prohormone production in health and disease, are considered. Finally, key next steps required to move forward in this area are outlined, including longitudinal testing of relevant clinical populations, studies that probe the genetics of altered prohormone processing, the need for combined functional and histologic testing of human pancreatic tissues, continued interrogation of the intersection between prohormone processing and autoimmunity, and optimal approaches for analysis. Successful resolution of these questions may offer the potential to use altered prohormone processing as a biomarker to inform therapeutic strategies aimed at personalized intervention during the natural history of type 1 diabetes and as a pathogenic anchor for identification of potential disease-specific endotypes.Item Analysis of Incident DKA in the Indiana New Onset T1D Patient Population(Indiana University, 2020) Beer, Brianna; Moors, Kelly; Evans-Molina, Carmella; Sims, Emily K.; Pediatrics, School of MedicineBackground/Objective: Diabetic ketoacidosis (DKA) is a life-threatening complication of type 1 diabetes (T1D) resulting from ketone body production and metabolic acidosis occurring due to insulin deficiency. We sought to define the occurrence of DKA amongst pediatric patients presenting with new-onset T1D in Indiana and to determine whether patterns of DKA were affected by the COVID-19 pandemic. Methods: This was a retrospective chart review for patients <18 years admitted to Riley Children’s Hospital with a clinical diagnosis of new onset T1D who had available chemistry values. Patients diagnosed from March 23- June 30, 2020 and over the same period in 2019 were included. DKA was classified as mild (bicarbonate 10-15 mmol/L) or severe (bicarbonate <10 mmol/L). Results: Ninety-four patients met inclusion criteria. The total number of incident T1D cases in 2019 and 2020 were similar (48 vs. 46, respectively). Similarly, there was no significant difference in rates of DKA (21 in 2019 vs. 25 in 2020; p>0.05). Of the 94 patients, 49% met criteria for DKA; 79% of cases were classified as severe and 21% as mild. More males were diagnosed with DKA in both 2019 and 2020 (61% of DKA cases). Non-Hispanic whites comprised 75% of all new onset T1D patients and no differences in race or ethnicity were present amongst those presenting in DKA. Conclusion: DKA was present in nearly half of all new onset pediatric T1D cases in Indiana in 2019 and 2020. There was no observed impact of the COVID-19 pandemic on T1D or DKA. Impact and Implications: DKA is common amongst pediatric patients with new onset T1D in Indiana. Prompt recognition of symptoms is needed to prevent this life-threatening complication of T1D.Item Analysis of serum Hsp90 as a potential biomarker of β cell autoimmunity in type 1 diabetes(PLOS, 2019-01-10) Ocaña, Gail J.; Sims, Emily K.; Watkins, Renecia A.; Ragg, Susanne; Mather, Kieren J.; Oram, Richard A.; Mirmira, Raghavendra G.; DiMeglio, Linda A.; Blum, Janice S.; Evans-Molina, Carmella; Microbiology and Immunology, School of MedicineHeat shock protein 90 (Hsp90) is a protein chaperone that is upregulated and released from pancreatic β cells under pro-inflammatory conditions. We hypothesized that serum Hsp90 may have utility as a biomarker of type 1 diabetes risk and exhibit elevations before the onset of clinically significant hyperglycemia. To this end, total levels of the alpha cytoplasmic isoform of Hsp90 were assayed in autoantibody-positive progressors to type 1 diabetes using banked serum samples from the TrialNet Pathway to Prevention Cohort that had been collected 12 months prior to diabetes onset, with comparison to age, sex, and BMI-category matched autoantibody-positive nonprogressors and healthy controls. Hsp90 levels were higher in autoantibody-positive progressors and nonprogressors ≤ 18 years of age compared to matched healthy controls. However, Hsp90 levels were not different between progressors and nonprogressors in any age group. Hsp90 was positively correlated with age in control subjects, but this correlation was absent in autoantibody positive individuals. In aggregate these data indicate that elevated Hsp90 levels are present in youth with β cell autoimmunity, but are not able to distinguish youth or adult type 1 diabetes progressors from nonprogressors in samples collected 12 months prior to diabetes development.Item Assessing the Pathophysiology of Hyperglycemia in the Diabetes RElated to Acute Pancreatitis and Its Mechanisms (DREAM) Study: From the Type 1 Diabetes in Acute Pancreatitis Consortium (T1DAPC)(Wolters Kluwer, 2022) Dungan, Kathleen M.; Hart, Phil A.; Andersen, Dana K.; Basina, Marina; Chinchilli, Vernon M.; Danielson, Kirstie K.; Evans-Molina, Carmella; Goodarzi, Mark O.; Greenbaum, Carla J.; Kalyani, Rita R.; Laughlin, Maren R.; Pichardo-Lowden, Ariana; Pratley, Richard E.; Serrano, Jose; Sims, Emily K.; Speake, Cate; Yadav, Dhiraj; Bellin, Melena D.; Toledo, Frederico G. S.; Type 1 Diabetes in Acute Pancreatitis Consortium; Medicine, School of MedicineObjectives: The metabolic abnormalities that lead to diabetes mellitus (DM) following an episode of acute pancreatitis (AP) have not been extensively studied. This manuscript describes the objectives, hypotheses, and methods of mechanistic studies of glucose metabolism that comprise secondary outcomes of the Diabetes RElated to Acute pancreatitis and its Mechanisms (DREAM) Study. Methods: Three months after an index episode of AP, participants without pre-existing DM will undergo baseline testing with an oral glucose tolerance test. Participants will be followed longitudinally in three sub-cohorts with distinct metabolic tests. In the first and largest subcohort, oral glucose tolerance tests will be repeated 12 months after AP and annually to assess changes in β-cell function, insulin secretion, and insulin sensitivity. In the second, mixed meal tolerance tests will be performed at 3 and 12 months, then annually, and following incident DM to assess incretin and pancreatic polypeptide responses. In the third, frequently-sampled intravenous glucose tolerance tests will be performed at 3 months and 12 months to assess the first-phase insulin response and more precisely measure β-cell function and insulin sensitivity. Conclusions: The DREAM study will comprehensively assess the metabolic and endocrine changes that precede and lead to the development of DM after AP.Item Associations of HbA1c with the Timing of C‐peptide Responses during the Oral Glucose Tolerance Test at the Diagnosis of Type 1 Diabetes(Wiley, 2019) Ismail, Heba M.; Evans-Molina, Carmella; DiMeglio, Linda A.; Becker, Dorothy J.; Libman, Ingrid; Sims, Emily K.; Boulware, David; Herold, Kevan C.; Rafkin, Lisa; Skyler, Jay; Cleves, Mario A.; Palmer, Jerry; Sosenko, Jay; Pediatrics, School of MedicineBackground In new onset type 1 diabetes (T1D), overall C‐peptide measures such as area under the curve (AUC) C‐peptide and peak C‐peptide are useful for estimating the extent of β‐cell dysfunction, and for assessing responses to intervention therapy. However, measures of the timing of C‐peptide responsiveness could have additional value. Objectives We assessed the contribution of the timing of C‐peptide responsiveness during oral glucose tolerance tests (OGTTs) to HbA1c variation at T1D diagnosis. Methods We analyzed data from 85 individuals <18 years with OGTTs and HbA1c measurements at diagnosis. Overall [AUC and peak C‐peptide] and timing measures [30‐0 minute C‐peptide (early); 60 to 120 minute C‐peptide sum‐30 minutes (late); 120/30 C‐peptide; time to peak C‐peptide] were utilized. Results At diagnosis, the mean (±SD) age was 11.2±3.3 years, BMI‐z was 0.4±1.1, 51.0% were male and the HbA1c was 43.54±8.46 mmol/mol (6.1±0.8%). HbA1c correlated inversely with the AUC C‐peptide (p<0.001), peak C‐peptide (p<0.001), early and late C‐peptide responses (p<0.001 each), and 120/30 C‐peptide (p<0.001). Those with a peak C‐peptide occurring at ≤60 minutes had higher HbA1c values than those with peaks later (p=0.003). HbA1c variance was better explained with timing measures added to regression models (R2=11.6% with AUC C‐peptide alone; R2=20.0% with 120/30 C‐peptide added; R2=13.7% with peak C‐peptide alone, R2=20.4% with timing of the peak added). Similar associations were seen between the 2‐hr glucose and the C‐peptide measures. Conclusions These findings show that the addition of timing measures of C‐peptide responsiveness better explains HbA1c variation at diagnosis than standard measures alone.Item Barriers to Screening: An Analysis of Factors Impacting Screening for Type 1 Diabetes Prevention Trials(Oxford University Press, 2023-01-11) Kinney, Mara; You, Lu; Sims, Emily K.; Wherrett, Diane; Schatz, Desmond; Lord, Sandra; Krischer, Jeffrey; Russell, William E.; Gottlieb, Peter A.; Libman, Ingrid; Buckner, Jane; DiMeglio, Linda A.; Herold, Kevan C.; Steck, Andrea K.; Pediatrics, School of MedicineContext: Participants with stage 1 or 2 type 1 diabetes (T1D) qualify for prevention trials, but factors involved in screening for such trials are largely unknown. Objective: To identify factors associated with screening for T1D prevention trials. Methods: This study included TrialNet Pathway to Prevention participants who were eligible for a prevention trial: oral insulin (TN-07, TN-20), teplizumab (TN-10), abatacept (TN-18), and oral hydroxychloroquine (TN-22). Univariate and multivariate logistic regression models were used to examine participant, site, and study factors at the time of prevention trial accrual. Results: Screening rates for trials were: 50% for TN-07 (584 screened/1172 eligible), 9% for TN-10 (106/1249), 24% for TN-18 (313/1285), 17% for TN-20 (113/667), and 28% for TN-22 (371/1336). Younger age and male sex were associated with higher screening rates for prevention trials overall and for oral therapies. Participants with an offspring with T1D showed lower rates of screening for all trials and oral drug trials compared with participants with other first-degree relatives as probands. Site factors, including larger monitoring volume and US site vs international site, were associated with higher prevention trial screening rates. Conclusions: Clear differences exist between participants who screen for prevention trials and those who do not screen and between the research sites involved in prevention trial screening. Participant age, sex, and relationship to proband are significantly associated with prevention trial screening in addition to key site factors. Identifying these factors can facilitate strategic recruitment planning to support rapid and successful enrollment into prevention trials.Item Beta cell extracellular vesicle miR-21-5p cargo is increased in response to inflammatory cytokines and serves as a biomarker of type 1 diabetes(Springer Nature, 2018-05) Lakhter, Alexander J.; Pratt, Rachel E.; Moore, Rachel E.; Doucette, Kaitlin K.; Maier, Bernhard F.; DiMeglio, Linda A.; Sims, Emily K.; Pediatrics, School of MedicineAIMS/HYPOTHESIS: Improved biomarkers are acutely needed for the detection of developing type 1 diabetes, prior to critical loss of beta cell mass. We previously demonstrated that elevated beta cell microRNA 21-5p (miR-21-5p) in rodent and human models of type 1 diabetes increased beta cell apoptosis. We hypothesised that the inflammatory milieu of developing diabetes may also increase miR-21-5p in beta cell extracellular vesicle (EV) cargo and that circulating EV miR-21-5p would be increased during type 1 diabetes development. METHODS: MIN6 and EndoC-βH1 beta cell lines and human islets were treated with IL-1β, IFN-γ and TNF-α to mimic the inflammatory milieu of early type 1 diabetes. Serum was collected weekly from 8-week-old female NOD mice until diabetes onset. Sera from a cross-section of 19 children at the time of type 1 diabetes diagnosis and 16 healthy children were also analysed. EVs were isolated from cell culture media or serum using sequential ultracentrifugation or ExoQuick precipitation and EV miRNAs were assayed. RESULTS: Cytokine treatment in beta cell lines and human islets resulted in a 1.5- to threefold increase in miR-21-5p. However, corresponding EVs were further enriched for this miRNA, with a three- to sixfold EV miR-21-5p increase in response to cytokine treatment. This difference was only partially reduced by pre-treatment of beta cells with Z-VAD-FMK to inhibit cytokine-induced caspase activity. Nanoparticle tracking analysis showed cytokines to have no effect on the number of EVs, implicating specific changes within EV cargo as being responsible for the increase in beta cell EV miR-21-5p. Sequential ultracentrifugation to separate EVs by size suggested that this effect was mostly due to cytokine-induced increases in exosome miR-21-5p. Longitudinal serum collections from NOD mice showed that EVs displayed progressive increases in miR-21-5p beginning 3 weeks prior to diabetes onset. To validate the relevance to human diabetes, we assayed serum from children with new-onset type 1 diabetes compared with healthy children. While total serum miR-21-5p and total serum EVs were reduced in diabetic participants, serum EV miR-21-5p was increased threefold compared with non-diabetic individuals. By contrast, both serum and EV miR-375-5p were increased in parallel among diabetic participants. CONCLUSIONS/INTERPRETATION: We propose that circulating EV miR-21-5p may be a promising marker of developing type 1 diabetes. Additionally, our findings highlight that, for certain miRNAs, total circulating miRNA levels are distinct from circulating EV miRNA content.