Pancreatic Beta-cell Function Research Articles

290-LB: Single-Cell Analysis of Endocrine Development Identifies Novel Roles for GLIS3 in Pancreatic ß-Cell Fate

The Krüppel-like zinc finger transcription factor GLIS3 has been identified as a critical regulator of pancreatic beta cell development and function. Mice lacking a functional Glis3 gene fail to produce enough insulin and suffer from severe hyperglycemia soon after birth. This phenotype matches what has been observed in humans with genetic mutations in GLIS3 and who have been diagnosed with permanent neonatal diabetes within the first month of life. Additional and ongoing work has begun to identify some of the transcriptional mechanisms utilized by GLIS3, yet many questions remain unanswered. One such question is whether GLIS3 has roles in endocrine development prior to the formation of functional β-cells. To address this question, I have utilized single cell RNA-sequencing of mouse embryonic pancreas, at embryonic days (e)15.5 and e18.5, of both wild type (WT) and Glis3 knockout (KO) embryos. Analysis of this data has identified the expected developmental populations, from bipotent progenitor cells to pro-endocrine cells and ultimately hormone positive β-, α-, δ-, and ε-cells. Interestingly, there is little difference in gene expression between the WT and Glis3 KO pancreas in most of the populations observed (pro-endocrine, FEV+, α-/δ-/ε-cells). However, there are significant differences in gene expression between WT β-cells and KO β-cells. Surprisingly, most of the differences are in genes upregulated in the KO cells, with only a small number of genes downregulated. These upregulated genes are normally downregulated over the course of development from FEV+ to β-cells. These data indicate that GLIS3 plays a unique role in developing β-cells in that it primarily represses genes during the course of development but is also critical for the transcriptional activation of specific targets, particularly Ins2. Understanding how GLIS3 regulates β-cell generation, and how GLIS3 itself is regulated, could potentially provide new therapeutic avenues for the treatment of diabetes. Disclosure D. W. Scoville: None. S. Grimm: None. A. M. Jetten: None. Funding National Institutes of Health (Z01-ES-101585)

771-P: Tirzepatide Reduces HbA1c and Body Weight Significantly More than Placebo or Semaglutide Irrespective of Baseline Beta-Cell Function—Post Hoc Analysis from SURPASS-1 and SURPASS-2

Tirzepatide (TZP), a once-weekly GIP/GLP-1 receptor agonist, achieved significantly greater HbA1c and body weight (BW) reductions with all doses (5, 10, 15 mg) vs placebo (SURPASS-1 [S-1]) and semaglutide (SEMA) 1 mg (SURPASS-2 [S-2]) in randomized Phase 3 trials in people with type 2 diabetes controlled by diet and exercise (S-1) or metformin (S-2). Exploratory post hoc analyses examined changes from baseline in HbA1c and BW in these studies at 40 weeks across HOMA2-B (C-peptide) and HOMA2-IR (insulin) quartiles (Q) from low (lower beta-cell function/insulin resistance) (Q1) to high (Q4) as assessed by mixed model repeated measures (MMRM). HbA1c reductions were greater with all TZP doses than placebo or SEMA within each HOMA2-B and HOMA2-IR baseline Q. HbA1c reductions were largest in people within HOMA-2B Q1, yet similar across all HOMA2-IR Qs (Fig). BW reductions were greater across Qs with all TZP doses (ranging from 6%-14%) than placebo (up to 2%) or SEMA (up to 7%). TZP was more efficacious than placebo or SEMA in reducing HbA1c and BW across a spectrum of pancreatic beta-cell function, notably achieving greater glycemic improvement in people with markers of diminished pancreatic beta cell function at baseline. Disclosure J.M.Maldonado: Employee; Eli Lilly and Company. C.De block: Advisory Panel; Abbott Diagnostics, Indigo Diabetes, Insulet Corporation, Eli Lilly and Company, Novo Nordisk, Research Support; Boehringer-Ingelheim, AstraZeneca, Indigo Diabetes, Eli Lilly and Company, Speaker's Bureau; Novo Nordisk. J.P.Frias: Advisory Panel; Becton, Dickinson and Company, Pfizer Inc., Sanofi, Consultant; Akero Therapeutics, Inc., 89bio, Inc., Aimmune, Boehringer Ingelheim Inc., Eli Lilly and Company, Carmot Therapeutics, Inc., Echosens, Merck & Co., Inc., Metacrine, Inc., Novo Nordisk, Pfizer Inc., Sanofi, Employee; Ionis Pharmaceuticals, Research Support; Akero Therapeutics, Inc., 89bio, Inc., Altimmune, Axcella Health Inc., Boehringer Ingelheim Inc., Eli Lilly and Company, Intercept Pharmaceuticals, Inc., Carmot Therapeutics, Inc., Janssen Pharmaceuticals, Inc., Madrigal Pharmaceuticals, Inc., Merck & Co., Inc., Metacrine, Inc., Novo Nordisk, Oramed Pharmaceuticals, Novartis, Pfizer Inc., Sanofi, Speaker's Bureau; Eli Lilly and Company, Sanofi. C.Lee: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. K.Brown: Employee; Eli Lilly and Company. H.Wang: None. M.K.Thomas: Employee; Eli Lilly and Company, Stock/Shareholder; Eli Lilly and Company. Funding Eli Lilly and Company

1760-P: Mining Animal Venoms as a Source of Insulinotropic Peptides for Potential Diabetes Therapy

T2D development and progression is widely known to be caused by pancreatic beta cell dysfunction, whether in the presence or absence of insulin resistance. There are however limited diabetes drugs that directly target the beta cell. Hence, there is a need to discover yet untapped pathways to increase or rescue beta cell function. Animal venoms provide a rich resource of bioactive compounds, many of which are highly potent and selective. Venom peptides have been harnessed for therapeutic drug development, such as the blockbuster diabetes drug, exenatide, a GLP-1 receptor agonist, being a synthetic form of exendin-4 that was first isolated from the saliva of the Gila monster. We hypothesize that we can further discover and develop new therapeutic agents that promote pancreatic beta cell function based on venom-derived compounds. We studied up to seven animal venoms from snakes, bees and scorpions. Pancreatic beta cells (including EndoC-βH1 cells, human islets, and MIN6 cells) were treated with crude animal venoms from each species and evaluated for insulin secretion capacity. We used a range of doses that elicit insulin secretion without causing cellular damage. Venoms from Apis mellifera (honey bee) and Naja naja (Indian cobra) were shown to robustly stimulate insulin secretion in a dose-dependent manner without affecting cell viability. Treatment with these venoms were also able to rescue diabetic cell models. We prioritized these two venoms for fractionation via gel filtration and reverse phase HPLC. After subsequent screening of the venom sub-fractions in insulin secretion assays, we pinpointed specific sub-fractions responsible for stimulating insulin release. Ongoing work is in progress to identify and validate selected peptides for insulinotropic activity, safety and stability. The insulinotropic peptides (and any modifications) may represent new therapeutic strategies for tackling T2D in future. Disclosure N.Ng: Stock/Shareholder; BetaLife. C.Koh: None. C.Ching: None. P.Gopalakrishnakone: None. A.Teo: None. Funding A*STAR Career Development Fund (202D800020)

298-OR: Safety and Efficacy of Immunomodulatory Therapy Using Antithymocyte Globulin and Pegfilgrastim in Japanese Patients with Type 1 Diabetes—A Pilot Randomized Clinical Trial

While immunomodulatory therapy using low-dose anti-thymocyte globulin (ATG) has been shown to be efficacious in preserving pancreatic beta-cell function in patients with type 1 diabetes (T1D) in the United States, no clinical trials of immunomodulatory therapy for T1D have been reported in Asia. In this study, we first evaluated the safety and efficacy of ATG/pegfilgrastim (PEG) therapy in Japanese patients with T1D. This was a pilot, open-label, randomized clinical trial. Twelve patients, with the age ≥ 20 years, T1D duration < 12 months, and serum CPR ≥ 0.3 ng/ml, were randomized into the ATG/PEG group (A/P; n = 6) and control group (Ctrl; n = 6). The A/P was administered 2.0 mg/kg ATG and six times of 3.5 mg PEG. The primary endpoint was the frequency of adverse events (AEs), which were evaluated per the CTCAE v5.0, and secondary endpoints included the percentages of decline (%Dec) in CPR-area under the curve (AUC) after mixed-meal loading, the SUIT index, and changes in glycemic control during an observation period of 104 weeks. Regarding safety, no grade 4 and 5 AEs were reported in either group. Grade 3 lymphocytopenia, which is considered to be the clinical effect of ATG, was noted in all 6 patients in the A/P. One severe AE, cellulitis, was reported in the Ctrl. The frequencies of infection were not significantly different between the two groups. Regarding efficacy, %Dec in CPR-AUC in 52 weeks was less than the median value in 5 out of 6 patients in the A/P, whereas 1 out of 5 patients in Ctrl (P = 0.03). Additionally, %Dec in the SUIT index in 104 weeks tended to be lower in the A/P than in the Ctrl (P = 0.06). Changes in HbA1c and glycated albumin levels and the amount of insulin administered were not significantly different between the two groups. In conclusion, ATG/PEG therapy was safely administered to Japanese patients with T1D. Larger scale trials and mechanistic analyses are required to confirm the efficacy of this treatment. Disclosure D.Chujo: None. N.Ohmagari: None. H.Ohyanagi: None. M.Shimoda: None. K.Ueki: Advisory Panel; Abbott Japan Co., Ltd., Research Support; Abbott Japan Co., Ltd., Boehringer Ingelheim Japan, Inc., Eli Lilly Japan K.K., Sumitomo Dainippon Pharma Co., Ltd., Novo Nordisk, Sanofi K.K., MSD Life Science Foundation, Takeda Pharmaceutical Co., Ltd., Speaker's Bureau; Boehringer Ingelheim Japan, Inc., Eli Lilly Japan K.K., Astellas Pharma Inc., AstraZeneca, Sumitomo Dainippon Pharma Co., Ltd., Novo Nordisk, Taiho Pharmaceutical Co. Ltd., Kowa Company, Ltd., Mitsubishi Tanabe Pharma Corporation, Ono Pharmaceutical Co., Ltd. H.Kajio: None. K.Tobe: Other Relationship; MSD K.K., Novo Nordisk Pharma Ltd., Takeda Pharmaceutical Company Limited, Daiichi Sankyo, Mitsubishi Tanabe Pharma Corporation, Suntory Global Corporation, Ltd.,, Taiho Pharmaceutical Co. Ltd., Japan Diabetes Foundation, Japan Association for Diabetes Education and Care. A.Enkaku: None. M.Kamigishi: None. A.Takikawa: None. M.Matsushita: None. M.Kobayashi: None. K.Yamamoto: None. T.Sato: None. Y.Yamamoto: None. Funding National Center for Global Health and Medicine (28A1204); Japan IDDM Network

289-LB: Intestinal Stem Cells as a Source of Insulin-Positive Beta-Like Cells for Treating Diabetes

Shortage of functional pancreatic beta-cells is the basic cause of type 1 and some late-stage type 2 diabetes, making generation of new beta-cells from stem cells a promising strategy for treating diabetes. Intestinal stem cells (ISCs) are adult stem cells found in the base of the crypts of the adult intestine, which is responsible for the continuous life-long renewal of intestinal epithelia cells and thus could also be used a potential source for autologous transplantation. Unlike the most extensively studied bone marrow derived stem cells, ISCs share the advantage of having a common endodermic origin with beta-cells, making their differentiation into beta-cells easier. However, purifying ISCs has been a challenge. Here, we reported a novel method that successfully purifies ISCs from wildtype mice by exploiting their specific binding to a lectin. The only other cell type in the intestine that also binds to this lectin was found to be Paneth cells, which could be excluded through a negative selection for CD24. The purified Lectin+CD24-ISCs, confirmed by gene profiling, were labeled with a fluorescent tag and shown to differentiate into insulin-producing beta-like cells when injected into day 11.5 mouse embryonic pancreatic explants and grown for a week. Further analysis of gene profile alterations and signaling pathways allowed us to develop a time-sensitive protocol with recombinant growth factors to optimize the differentiation of ISCs into beta-like cells in vitro, without the need for an embryonic environment. Our results not only demonstrate a new method for purifying ISCs, but also their potential to differentiate into insulin-producing beta-like cells. This study provides a promising strategy for beta-cell replacement therapy in diabetes. Disclosure Y. Xiao: None. Y. Xiao: None. Y. Jiang: None. Funding University of Pittsburgh; Children?s Hospital of Pittsburgh; Cochrane-Weber Endowed Fund in Diabetes Research

Ca2+-Mediated Signaling Pathways: A Promising Target for the Successful Generation of Mature and Functional Stem Cell-Derived Pancreatic Beta Cells In Vitro.

Diabetes mellitus is a chronic disease affecting over 500 million adults globally and is mainly categorized as type 1 diabetes mellitus (T1DM), where pancreatic beta cells are destroyed, and type 2 diabetes mellitus (T2DM), characterized by beta cell dysfunction. This review highlights the importance of the divalent cation calcium (Ca2+) and its associated signaling pathways in the proper functioning of beta cells and underlines the effects of Ca2+ dysfunction on beta cell function and its implications for the onset of diabetes. Great interest and promise are held by human pluripotent stem cell (hPSC) technology to generate functional pancreatic beta cells from diabetic patient-derived stem cells to replace the dysfunctional cells, thereby compensating for insulin deficiency and reducing the comorbidities of the disease and its associated financial and social burden on the patient and society. Beta-like cells generated by most current differentiation protocols have blunted functionality compared to their adult human counterparts. The Ca2+ dynamics in stem cell-derived beta-like cells and adult beta cells are summarized in this review, revealing the importance of proper Ca2+ homeostasis in beta-cell function. Consequently, the importance of targeting Ca2+ function in differentiation protocols is suggested to improve current strategies to use hPSCs to generate mature and functional beta-like cells with a comparable glucose-stimulated insulin secretion (GSIS) profile to adult beta cells.

Diabetic Neuropathy of the Retina and Inflammation: Perspectives.

A clear connection exists between diabetes and atherosclerotic cardiovascular disease. Consequently, therapeutic approaches that target both diseases are needed. Clinical trials are currently underway to explore the roles of obesity, adipose tissue, gut microbiota, and pancreatic beta cell function in diabetes. Inflammation plays a key role in diabetes pathophysiology and associated metabolic disorders; thus, interest has increased in targeting inflammation to prevent and control diabetes. Diabetic retinopathy is known as a neurodegenerative and vascular disease that occurs after some years of poorly controlled diabetes. However, increasing evidence points to inflammation as a key figure in diabetes-associated retinal complications. Interconnected molecular pathways, such as oxidative stress, and the formation of advanced glycation end-products, are known to contribute to the inflammatory response. This review describes the possible mechanisms of the metabolic changes in diabetes that involve inflammatory pathways.

Serum fibroblast growth factor 1 and its association with pancreatic beta cell function and insulin sensitivity in adults with glucose intolerance.

Beneficial role of fibroblast growth factor 1 (FGF1) in the regulation of glucose metabolism and adipose tissue remodeling was suggested in rodents. This study aimed to investigate the association between serum FGF1 levels and metabolic parameters in adults with glucose intolerance. Serum FGF1 levels were examined using an enzyme-linked immunosorbent assay in 153 individuals with glucose intolerance. Associations between serum FGF1 levels and metabolic parameters, including body mass index (BMI), glycated hemoglobin (HbA1c), and 75 g oral glucose tolerance test-derived parameters, including insulinogenic index (IGI), Matsuda insulin sensitivity index (ISI), and disposition index (DI), were examined. Serum FGF1 was detected in 35 individuals (22.9%), possibly due to the autocrine/paracrine nature of the peptide. IGI and DI levels were significantly lower in individuals with higher FGF1 levels than in those with lower FGF1 levels or undetectable FGF1 (p=0.006 and 0.005 for IGI and DI, respectively, after adjustment for age, sex, and BMI). Univariable and multivariable analyses using the Tobit regression model also revealed a negative association between FGF1 levels and IGI and DI. The regression coefficients per 1-SD of log-transformed IGI and DI were -0.461 (p=0.013) and -0.467 (p=0.012), respectively, after adjustment for age, sex, and BMI. In contrast, serum FGF1 levels were not significantly associated with ISI, BMI, or HbA1c. The serum concentration of FGF1 was significantly elevated in individuals with low insulin secretion, suggesting a possible interaction between FGF1 and beta cell function in humans.

Single Nucleotide Polymorphism at rs7903146 of Transcription Factor 7-like 2 gene Among Subjects with Type 2 Diabetes Mellitus in Myanmar.

To investigate the association between the single nucleotide polymorphism (SNP) rs7903146 in the transcription factor 7-like 2 (TCF7L2) gene and type 2 diabetes mellitus (T2DM) and to examine the impact of this variant on pancreatic beta-cell function in the Myanmar population. A case-control study was undertaken in 100 subjects with T2DM and 113 controls. The SNP rs7903146 was genotyped using the allele-specific polymerase chain reaction method. Plasma glucose and serum insulin levels were determined using the enzymatic colorimetric method and ELISA respectively. Beta-cell function was calculated by the HOMA-β formula. The frequencies of carrier genotypes (CT and TT) were higher in subjects with T2DM than in controls. The minor T alleles of rs7903146 were found to statistically increase type 2 diabetes risk than the C allele with an allelic odds ratio of 2.07 (95% CI 1.39-3.09, p=0.0004). The mean HOMA-β level of the group with non-carrier genotype (CC) was significantly higher than that of the groups with carrier genotypes (CT and TT) in subjects with T2DM and controls with a p-value of 0.0003 and less than 0.0001, respectively. The rs7903146 variant of the TCF7L2 gene was found to be associated with T2DM and low β-cell function among Myanmar subjects.

Abstract #1412358: A Case of Neonatal Diabetes

Neonatal diabetes is a term commonly used to describe the different forms of monogenic diabetes that present in infancy. The average time of presentation is within six months of age however it can present up to 12 months of age. This contrasts to type 1 diabetes which rarely presents within the first six months of life. The incidence of neonatal diabetes is estimated to be 1 in 90,000 to 160,000 live births. There have been over 30 genetic mutations identified that affect pancreatic beta cell function. The phenotypic expression of these mutations varies from transient diabetes (20% of cases), to diabetes responsive to sulfonylurea (40% of cases), to permanent diabetes requiring lifelong insulin therapy (10% of cases), to syndromic and autoimmune diabetes with extra pancreatic features. Here we present a case of neonatal diabetes secondary to a KCNJ11 mutation being treated with sulfonylurea. A 24-year-old male with a past medical history of diabetes mellitus diagnosed at three months of age, behavioral disorders and developmental delay is being managed in Endocrinology clinic for uncontrolled diabetes complicated by multiple admissions with diabetic ketoacidosis. He has a family history of type 2 diabetes in his father. The patient was initially diagnosed and treated as a type I diabetic until at ten years of age genetic testing confirmed a heterozygous R201C mutation of the KCJN11 gene consistent with the diagnosis of neonatal diabetes. He was successfully switched from insulin to high doses of glyburide including 50mg with breakfast, 50mg with dinner, and 30mg at bedtime. The hemoglobin A1c ranged 11-12% due to issues with non-adherence, so Tresiba 22 units at bedtime was added. At the age of 19, the patient transferred care to adult Endocrinology. His exam was remarkable for a BMI of 23 and difficulty with serial seven count down and five-word recall. Relevant labs included c-peptide < 0.1, negative GAD65 Ab, A1c 13%. After an admission for DKA, the patient was prescribed Glargine 28 units daily and Humalog 20 units before meals. Due to difficulty titrating and adhering to this insulin regimen, he was recently restarted this year on glyburide 50mg twice a day with Tresiba 15 units at bedtime with plan to titrate up the doses of the sulfonylurea and discontinue insulin. Mutations in KCNJ11 and ABCC8 are the most common affecting around 46% of infants with neonatal diabetes. They encode for subunits of the ATP-sensitive potassium channel (KATP), which affects the membrane depolarization required for insulin exocytosis in the pancreatic beta cell. Infants with these mutations may also present with varying degrees of neurodevelopmental and psychiatric problems due to presence of KATP channels in the brain. Early treatment with sulfonylurea may improve neurologic outcomes. It is estimated that 80-90% of patients with these mutations will respond to sulfonylurea treatment with high doses of glyburide (up to 2.5mg/kg per day) and eliminate the need for insulin, while 10% may not respond and may still need insulin.

Effect of verapamil on pancreatic beta cell function in newly diagnosed type 1 diabetes in children

Effect of verapamil on pancreatic beta cell function in newly diagnosed type 1 diabetes in children

PIMT Controls Insulin Synthesis and Secretion through PDX1.

Pancreatic beta cell function is an important component of glucose homeostasis. Here, we investigated the function of PIMT (PRIP-interacting protein with methyl transferase domain), a transcriptional co-activator binding protein, in the pancreatic beta cells. We observed that the protein levels of PIMT, along with key beta cell markers such as PDX1 (pancreatic and duodenal homeobox 1) and MafA (MAF bZIP transcription factor A), were reduced in the beta cells exposed to hyperglycemic and hyperlipidemic conditions. Consistently, PIMT levels were reduced in the pancreatic islets isolated from high fat diet (HFD)-fed mice. The RNA sequencing analysis of PIMT knockdown beta cells identified that the expression of key genes involved in insulin secretory pathway, Ins1 (insulin 1), Ins2 (insulin 2), Kcnj11 (potassium inwardly-rectifying channel, subfamily J, member 11), Kcnn1 (potassium calcium-activated channel subfamily N member 1), Rab3a (member RAS oncogene family), Gnas (GNAS complex locus), Syt13 (synaptotagmin 13), Pax6 (paired box 6), Klf11 (Kruppel-Like Factor 11), and Nr4a1 (nuclear receptor subfamily 4, group A, member 1) was attenuated due to PIMT depletion. PIMT ablation in the pancreatic beta cells and in the rat pancreatic islets led to decreased protein levels of PDX1 and MafA, resulting in the reduction in glucose-stimulated insulin secretion (GSIS). The results from the immunoprecipitation and ChIP experiments revealed the interaction of PIMT with PDX1 and MafA, and its recruitment to the insulin promoter, respectively. Importantly, PIMT ablation in beta cells resulted in the nuclear translocation of insulin. Surprisingly, forced expression of PIMT in beta cells abrogated GSIS, while Ins1 and Ins2 transcript levels were subtly enhanced. On the other hand, the expression of genes, PRIP/Asc2/Ncoa6 (nuclear receptor coactivator 6), Pax6, Kcnj11, Syt13, Stxbp1 (syntaxin binding protein 1), and Snap25 (synaptosome associated protein 25) associated with insulin secretion, was significantly reduced, providing an explanation for the decreased GSIS upon PIMT overexpression. Our findings highlight the importance of PIMT in the regulation of insulin synthesis and secretion in beta cells.

Non-invasive imaging of functional pancreatic islet beta-cell mass in people with type 1 diabetes mellitus.

To investigate whether manganese-enhanced magnetic resonance imaging can assess functional pancreatic beta-cell mass in people with type 1 diabetes mellitus. In a prospective case-control study, 20 people with type 1 diabetes mellitus (10 with low (≥50 pmol/L) and 10 with very low (<50 pmol/L) C-peptide concentrations) and 15 healthy volunteers underwent manganese-enhanced magnetic resonance imaging of the pancreas following an oral glucose load. Scan-rescan reproducibility was performed in 10 participants. Mean pancreatic manganese uptake was 31 ± 6 mL/100 g of tissue/min in healthy volunteers (median 32 [interquartile range 23-36] years, 6 women), falling to 23 ± 4 and 13 ± 5 mL/100 g of tissue/min (p ≤ 0.002 for both) in people with type1 diabetes mellitus (52 [44-61] years, 6 women) and low or very low plasma C-peptide concentrations respectively. Pancreatic manganese uptake correlated strongly with plasma C-peptide concentrations in people with type1 diabetes mellitus (r = 0.73, p < 0.001) but not in healthy volunteers (r = -0.054, p = 0.880). There were no statistically significant correlations between manganese uptake and age, body-mass index, or glycated haemoglobin. There was strong intra-observer (mean difference: 0.31 (limits of agreement -1.42 to 2.05) mL/100 g of tissue/min; intra-class correlation, ICC = 0.99), inter-observer (-1.23 (-5.74 to 3.27) mL/100 g of tissue/min; ICC = 0.85) and scan-rescan (-0.72 (-2.9 to 1.6) mL/100 g of tissue/min; ICC = 0.96) agreement for pancreatic manganese uptake. Manganese-enhanced magnetic resonance imaging provides a potential reproducible non-invasive measure of functional beta-cell mass in people with type 1 diabetes mellitus. This holds major promise for investigating type 1 diabetes, monitoring disease progression and assessing novel immunomodulatory interventions.

Development of Imeglimin Electrospun Nanofibers as a Potential Buccal Antidiabetic Therapeutic Approach.

The prevalence of type 2 diabetes (T2D) has been growing worldwide; hence, safe and effective antidiabetics are critically warranted. Recently, imeglimin, a novel tetrahydrotriazene compound, has been approved for use in T2D patients in Japan. It has shown promising glucose-lowering properties by improving pancreatic beta-cell function and peripheral insulin sensitivity. Nevertheless, it has several drawbacks, including suboptimal oral absorption and gastrointestinal (GI) discomfort. Therefore, this study aimed to fabricate a novel formulation of imeglimin loaded into electrospun nanofibers to be delivered through the buccal cavity to overcome the current GI-related adverse events and to provide a convenient route of administration. The fabricated nanofibers were characterized for diameter, drug-loading (DL), disintegration, and drug release profiles. The data demonstrated that the imeglimin nanofibers had a diameter of 361 ± 54 nm and DL of 23.5 ± 0.2 μg/mg of fibers. The X-ray diffraction (XRD) data confirmed the solid dispersion of imeglimin, favoring drug solubility, and release with improved bioavailability. The rate of drug-loaded nanofibers disintegration was recorded at 2 ± 1 s, indicating the rapid disintegration ability of this dosage form and its suitability for buccal delivery, with a complete drug release after 30 min. The findings of this study suggest that the developed imeglimin nanofibers have the potential to be given via the buccal route, thereby achieving optimal therapeutic outcomes and improving patient compliance.

Validation of Doi's weighted average glucose as a measure of post-load glucose excursion for clinical use.

In this study, we examined the performance of a novel index of glucose excursion (Doi’s weighted average glucose [dwAG]) in relation to the conventional measure of area under the oral glucose tolerance test (A-GTT) and the homeostatic model assessment for insulin sensitivity (HOMA-S) and pancreatic beta cell function (HOMA-B). A cross-sectional comparison of the new index was conducted using 66 oral glucose tolerance tests (GTTs) performed at different follow-up times among 27 participants who had undergone surgical subcutaneous fat removal (SSFR). Comparisons across categories were made using box plots and the Kruskal-Wallis one-way ANOVA on ranks. Passing-Bablok regression was used to compare the dwAG against the conventional A-GTT. The Passing-Bablok regression model suggested a cutoff for normality for the A-GTT of 15.14 mmol/L·2h-1 compared to the dwAG’s suggested threshold of 6.8 mmol/L. For every 1 mmol/L·2h-1 increase in A-GTT, the dwAG value increased by 0.473 mmol/L. The glucose area under the curve correlated well with the four defined dwAG categories, with at least one of the categories having a different median A-GTT value (KW Chi2 = 52.8 [df = 3], P < 0.001). The HOMA-S tertiles were also associated with significantly different levels of glucose excursion measured through both the dwAG value (KW Chi2 = 11.4 [df = 2], P = 0.003) and A-GTT measure (KW Chi2 = 13.1 [df = 2], P = 0.001). It is concluded that the dwAG value and categories serve as a simple and accurate tool that can be used for interpreting glucose homeostasis across clinical settings.

EpiCRISPR targeted methylation of Arx gene initiates transient switch of mouse pancreatic alpha to insulin-producing cells.

Beta cell dysfunction by loss of beta cell identity, dedifferentiation, and the presence of polyhormonal cells are main characteristics of diabetes. The straightforward strategy for curing diabetes implies reestablishment of pancreatic beta cell function by beta cell replacement therapy. Aristaless-related homeobox (Arx) gene encodes protein which plays an important role in the development of pancreatic alpha cells and is a main target for changing alpha cell identity. In this study we used CRISPR/dCas9-based epigenetic tools for targeted hypermethylation of Arx gene promoter and its subsequent suppression in mouse pancreatic αTC1-6 cell line. Bisulfite sequencing and methylation profiling revealed that the dCas9-Dnmt3a3L-KRAB single chain fusion constructs (EpiCRISPR) was the most efficient. Epigenetic silencing of Arx expression was accompanied by an increase in transcription of the insulin gene (Ins2) mRNA on 5th and 7th post-transfection day, quantified by both RT-qPCR and RNA-seq. Insulin production and secretion was determined by immunocytochemistry and ELISA assay, respectively. Eventually, we were able to induce switch of approximately 1% of transiently transfected cells which were able to produce 35% more insulin than Mock transfected alpha cells. In conclusion, we successfully triggered a direct, transient switch of pancreatic alpha to insulin-producing cells opening a future research on promising therapeutic avenue for diabetes management.

Tirzepatide as Monotherapy Improved Markers of Beta-cell Function and Insulin Sensitivity in Type 2 Diabetes (SURPASS-1).

Tirzepatide is a glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist approved for treatment of type 2 diabetes (T2D). SURPASS-1, a phase 3 trial of tirzepatide monotherapy in people with early T2D, enables evaluating effects of tirzepatide on pancreatic beta-cell function and insulin sensitivity (IS) without other background antihyperglycemic medications. Explore changes in biomarkers of beta-cell function and IS with tirzepatide monotherapy. Post hoc analyses of fasting biomarkers with analysis of variance and mixed model repeated measures. Forty-seven sites in 4 countries. Four hundred seventy-eight T2D participants. Tirzepatide (5, 10, 15 mg), placebo. Analyze biomarkers of beta-cell function and IS at 40 weeks. At 40 weeks, markers of beta-cell function improved with tirzepatide monotherapy vs placebo with reductions from baseline in fasting proinsulin levels (49-55% vs -0.6%) and in intact proinsulin/C-peptide ratios (47-49% vs -0.1%) (P < .001, all doses vs placebo). Increases from baseline in homeostatic model assessment for beta-cell function (computed with C-peptide) (77-92% vs -1.4%) and decreases in glucose-adjusted glucagon levels (37-44% vs +4.8%) were observed with tirzepatide vs placebo (P < .001, all doses vs placebo). IS improved as indicated by reductions from baseline in homeostatic model assessment for insulin resistance (9-23% vs +14.7%) and fasting insulin levels (2-12% vs +15%), and increases in total adiponectin (16-23% vs -0.2%) and insulin-like growth factor binding protein 2 (38-70% vs +4.1%) with tirzepatide vs placebo at 40 weeks (P ≤ .031, all doses vs placebo, except for fasting insulin levels with tirzepatide 10 mg). As monotherapy for early T2D, tirzepatide achieved significant improvements in biomarkers of both pancreatic beta-cell function and IS.

Gene–environment interactions in the associations of PFAS exposure with insulin sensitivity and beta-cell function in a Faroese cohort followed from birth to adulthood

BackgroundExposure to perfluoroalkyl substances (PFAS) has been associated with changes in insulin sensitivity and pancreatic beta-cell function in humans. Genetic predisposition to diabetes may modify these associations; however, this hypothesis has not been yet studied. ObjectivesTo evaluate genetic heterogeneity as a modifier in the PFAS association with insulin sensitivity and pancreatic beta-cell function, using a targeted gene–environment (GxE) approach. MethodsWe studied 85 single-nucleotide polymorphisms (SNPs) associated with type 2 diabetes, in 665 Faroese adults born in 1986–1987. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were measured in cord whole blood at birth and in participants’ serum from age 28 years. We calculated the Matsuda-insulin sensitivity index (ISI) and the insulinogenic index (IGI) based on a 2 h-oral glucose tolerance test performed at age 28. Effect modification was evaluated in linear regression models adjusted for cross-product terms (PFAS*SNP) and important covariates. ResultsPrenatal and adult PFOS exposures were significantly associated with decreased insulin sensitivity and increased beta-cell function. PFOA associations were in the same direction but attenuated compared to PFOS. A total of 58 SNPs were associated with at least one PFAS exposure variable and/or Matsuda-ISI or IGI in the Faroese population and were subsequently tested as modifiers in the PFAS-clinical outcome associations. Eighteen SNPs showed interaction p-values (PGxE) < 0.05 in at least one PFAS-clinical outcome association, five of which passed False Discovery Rate (FDR) correction (PGxE-FDR<0.20). SNPs for which we found stronger evidence for GxE interactions included ABCA1 rs3890182, FTO rs9939609, FTO rs3751812, PPARG rs170036314 and SLC12A3 rs2289116 and were more clearly shown to modify the PFAS associations with insulin sensitivity, rather than with beta-cell function. DiscussionFindings from this study suggest that PFAS-associated changes in insulin sensitivity could vary between individuals as a result of genetic predisposition and warrant replication in independent larger populations.

Effect of Tight Glycemic Control on Pancreatic Beta Cell Function in Newly Diagnosed Pediatric Type 1 Diabetes

Near normalization of glucose levels instituted immediately after diagnosis of type 1 diabetes has been postulated to preserve pancreatic beta cell function by reducing glucotoxicity. Previous studies have been hampered by an inability to achieve tight glycemic goals. To determine the effectiveness of intensive diabetes management to achieve near normalization of glucose levels on preservation of pancreatic beta cell function in youth with newly diagnosed type 1 diabetes. This randomized, double-blind, clinical trial was conducted at 6 centers in the US (randomizations from July 20, 2020, to October 13, 2021; follow-up completed September 15, 2022) and included youths with newly diagnosed type 1 diabetes aged 7 to 17 years. Random assignment to intensive diabetes management, which included use of an automated insulin delivery system (n = 61), or standard care, which included use of a continuous glucose monitor (n = 52), as part of a factorial design in which participants weighing 30 kg or more also were assigned to receive either oral verapamil or placebo. The primary outcome was mixed-meal tolerance test-stimulated C-peptide area under the curve (a measure of pancreatic beta cell function) 52 weeks from diagnosis. Among 113 participants (mean [SD] age, 11.8 [2.8] years; 49 females [43%]; mean [SD] time from diagnosis to randomization, 24 [5] days), 108 (96%) completed the trial. The mean C-peptide area under the curve decreased from 0.57 pmol/mL at baseline to 0.45 pmol/mL at 52 weeks in the intensive management group, and from 0.60 to 0.50 pmol/mL in the standard care group (treatment group difference, -0.01 [95% CI, -0.11 to 0.10]; P = .89). The mean time in the target range of 70 to 180 mg/dL, measured with continuous glucose monitoring, at 52 weeks was 78% in the intensive management group vs 64% in the standard care group (adjusted difference, 16% [95% CI, 10% to 22%]). One severe hypoglycemia event and 1 diabetic ketoacidosis event occurred in each group. In youths with newly diagnosed type 1 diabetes, intensive diabetes management, which included automated insulin delivery, achieved excellent glucose control but did not affect the decline in pancreatic C-peptide secretion at 52 weeks. ClinicalTrials.gov Identifier: NCT04233034.

Effect of Verapamil on Pancreatic Beta Cell Function in Newly Diagnosed Pediatric Type 1 Diabetes

In preclinical studies, thioredoxin-interacting protein overexpression induces pancreatic beta cell apoptosis and is involved in glucotoxicity-induced beta cell death. Calcium channel blockers reduce these effects and may be beneficial to beta cell preservation in type 1 diabetes. To determine the effect of verapamil on pancreatic beta cell function in children and adolescents with newly diagnosed type 1 diabetes. This double-blind, randomized clinical trial including children and adolescents aged 7 to 17 years with newly diagnosed type 1 diabetes who weighed 30 kg or greater was conducted at 6 centers in the US (randomized participants between July 20, 2020, and October 13, 2021) and follow-up was completed on September 15, 2022. Participants were randomly assigned 1:1 to once-daily oral verapamil (n = 47) or placebo (n = 41) as part of a factorial design in which participants also were assigned to receive either intensive diabetes management or standard diabetes care. The primary outcome was area under the curve values for C-peptide level (a measure of pancreatic beta cell function) stimulated by a mixed-meal tolerance test at 52 weeks from diagnosis of type 1 diabetes. Among 88 participants (mean age, 12.7 [SD, 2.4] years; 36 were female [41%]; and the mean time from diagnosis to randomization was 24 [SD, 4] days), 83 (94%) completed the trial. In the verapamil group, the mean C-peptide area under the curve was 0.66 pmol/mL at baseline and 0.65 pmol/mL at 52 weeks compared with 0.60 pmol/mL at baseline and 0.44 pmol/mL at 52 weeks in the placebo group (adjusted between-group difference, 0.14 pmol/mL [95% CI, 0.01 to 0.27 pmol/mL]; P = .04). This equates to a 30% higher C-peptide level at 52 weeks with verapamil. The percentage of participants with a 52-week peak C-peptide level of 0.2 pmol/mL or greater was 95% (41 of 43 participants) in the verapamil group vs 71% (27 of 38 participants) in the placebo group. At 52 weeks, hemoglobin A1c was 6.6% in the verapamil group vs 6.9% in the placebo group (adjusted between-group difference, -0.3% [95% CI, -1.0% to 0.4%]). Eight participants (17%) in the verapamil group and 8 participants (20%) in the placebo group had a nonserious adverse event considered to be related to treatment. In children and adolescents with newly diagnosed type 1 diabetes, verapamil partially preserved stimulated C-peptide secretion at 52 weeks from diagnosis compared with placebo. Further studies are needed to determine the longitudinal durability of C-peptide improvement and the optimal length of therapy. ClinicalTrials.gov Identifier: NCT04233034.