C-peptide Measurements Research Articles

12450 Beyond the Surface: A Deep Dive into Pancreatic Insulinoma

Abstract Disclosure: S. Bhandari: None. R. Elhag: None. J. Singh: None. N. Rastogi: None. Background: Pancreatic neuroendocrine tumors (NET) are rare lesions that are typically sporadic, solitary and usually <2cm in diameter, with reported incidence of 4 cases per 1 million patients per year[1]. The most common hormone secreting NET are insulinomas. The hallmark of insulinomas is hypersecretion of insulin, leading to neuroglycopenic symptoms and uncontrolled sympathoadrenal activity. Clinical case: 51 years old female with no significant past medical history was referred to endocrine clinic by her primary care physician for hypoglycemia with a blood glucose level of 48 mg/dl. She reported an increased frequency of headaches and dizziness which began with intermittent fasting (10-12 hours) for past 6 months. These symptoms improved upon increasing meal frequency. Initial laboratory investigations revealed glucose of 54 mg/dl, normal HbA1c, and negative sulfonylurea panel. The patient had normal liver and kidney function with no malnutrition or malabsorption issues. Further work up showed C-peptide level 1.56 ng/ml (n 0.80-3.85ng/ml), insulin level 7.9 uIU/mL (n <18.4 uIU/mL), pro-insulin level significantly elevated at 77.6 pmol/L (n </= 18.8pmol/L) and beta hydroxybutyrate of 0.12 mmol/l (n 0.02-0.27mmol/l). Insulin like growth factor was normal. Insulin antibodies were negative, and pituitary hormones were within normal limits. Pancreatic ultrasound was normal. CT abdomen/pelvis showed a 0.8x1.1 cm homogenously hypervascular anterior pancreatic body soft tissue lesion consistent with NET. Patient was started on diazoxide and continuous glucose monitoring (CGM). She was referred to general surgery and underwent successful tumor resection. Insulinoma is suggested by Whipple's triad, which is presence of hypoglycemic symptoms, documented hypoglycemia and resolution of hypoglycemic symptoms after glucose administration. As clinical manifestations are non-specific, diagnosing an insulinoma is challenging and depends on collateral history and a high index of suspicion. The gold standard of diagnosis is supervised 72-hour fasting test with plasma glucose, insulin, C-peptide, and proinsulin level measurements. Medical management of insulinoma includes the use of diazoxide, calcium channel blockers, propranolol, and glucocorticoids. Surgery is definitive treatment for insulinomas, with cure rates ranging from 77 to 100%. Conclusion: Insulinomas are benign and curable in most cases but can be fatal if misdiagnosed. Incidental findings of hypoglycemia should warrant thorough diagnostic workup to facilitate timely diagnosis and management.

TNF-α inhibitors for type 1 diabetes: exploring the path to a pivotal clinical trial.

Type 1 diabetes (T1D) is an autoimmune disease characterized by the destruction of insulin-producing β-cells in the pancreas. This destruction leads to chronic hyperglycemia, necessitating lifelong insulin therapy to manage blood glucose levels. Typically diagnosed in children and young adults, T1D can, however, occur at any age. Ongoing research aims to uncover the precise mechanisms underlying T1D and to develop potential interventions. These include efforts to modulate the immune system, regenerate β-cells, and create advanced insulin delivery systems. Emerging therapies, such as closed-loop insulin pumps, stem cell-derived β-cell replacement and disease-modifying therapies (DMTs), offer hope for improving the quality of life for individuals with T1D and potentially moving towards a cure. Currently, there are no disease-modifying therapies approved for stage 3 T1D. Preserving β-cell function in stage 3 T1D is associated with better clinical outcomes, including lower HbA1c and decreased risk of hypoglycemia, neuropathy, and retinopathy. Tumor Necrosis Factor alpha (TNF-α) inhibitors have demonstrated efficacy at preserving β-cell function by measurement of C-peptide in two clinical trials in people with stage 3 T1D. However, TNF-α inhibitors have yet to be evaluated in a pivotal trial for T1D. To address the promising clinical findings of TNF-α inhibitors in T1D, Breakthrough T1D convened a panel of key opinion leaders (KOLs) in the field. The workshop aimed to outline an optimal clinical path for moving TNF-α inhibitors to a pivotal clinical trial in T1D. Here, we summarize the evidence for the beneficial use of TNF-α inhibitors in T1D and considerations for strategies collectively identified to advance TNF-α inhibitors beyond phase 2 clinical studies for stage 3 T1D.

Development and Validation of a Novel Isotope Dilution-Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Serum C-Peptide.

Mass spectrometry (MS) methods exhibit higher accuracy and comparability in measuring serum C-peptide concentrations than immunoassays. We developed and validated a novel isotope dilution-ultraperformance liquid chromatography-tandem MS (ID-UPLC-MS/MS) assay to measure serum C-peptide concentrations. Sample pretreatment involved solid-phase extraction, ion-exchange solid-phase extraction, and derivatization with 6-aminoquinolyl-N-hydroxysuccinimidylcarbamate (Cayman Chemical, Ann Arbor, Michigan, USA). We used an ExionLC UPLC system (Sciex, Framingham, MA, USA) and a Sciex Triple Quad 6500+ MS/MS system (Sciex) for electrospray ionization in positive-ion mode with multiple charge states of [M+3H]3+ and multiple reaction monitoring transitions. The total run time was 50 mins, and the flow rate was 0.20 mL/min. We evaluated the precision, trueness, linearity, lower limit of quantitation (LLOQ), carryover, and matrix effects. Method comparison with electrochemiluminescence immunoassay (ECLIA) was performed in 138 clinical specimens. The intra- and inter-run precision coefficients of variation were <5% and the bias values for trueness were <4%, which were all acceptable. The verified linear interval was 0.050-15 ng/mL, and the LLOQ was 0.050 ng/mL. No significant carryover or matrix effects were observed. The correlation between this ID-UPLC-MS/MS method and ECLIA was good (R=0.995, slope=1.564); however, the ECLIA showed a positive bias (51.8%). The developed ID-UPLC-MS/MS assay shows acceptable performance in measuring serum C-peptide concentrations. This will be useful in situations requiring accurate measurement of serum C-peptide in clinical laboratories.

α- or β-Adrenergic blockade does not affect transplanted islet cell responses to hypoglycemia in type 1 diabetes.

Type 1 diabetes recipients of intrahepatic islet transplantation exhibit glucose-dependent suppression of insulin and activation of glucagon secretion in response to insulin-induced hypoglycemia associated with clinical protection from hypoglycemia. Whether sympathetic activation of adrenergic receptors on transplanted islets is required for these responses in defense against hypoglycemia is not known. To evaluate the adrenergic contribution to posttransplant glucose counterregulation, we performed a randomized, double-blind crossover study of responses during a hyperinsulinemic euglycemic-hypoglycemic clamp under phentolamine (α-adrenergic blockage), propranolol (β-adrenergic blockage), or placebo infusion. Characteristics of participants (5 females/4 males) were as follows: median (range) age 53 (34-63) yr, diabetes duration 29 (18-56) yr, posttransplant 7.0 (1.9-8.4) yr, HbA1c 5.8 (4.5-6.8)%, insulin in-/dependent 5/4, all on tacrolimus-based immunosuppression. During the clamp, blood pressure was lower with phentolamine and heart rate was lower with propranolol versus placebo (P < 0.05). There was no difference in the suppression of endogenous insulin secretion (derived from C-peptide measurements) during the euglycemic or hypoglycemic phases, and although levels of glucagon were similar with phentolamine or propranolol vs. placebo, the increase in glucagon from eu- to hypoglycemia was greater with propranolol vs. placebo (P < 0.05). Pancreatic polypeptide was greater with phentolamine versus placebo during the euglycemic phase (P < 0.05), and free fatty acids were lower and the glucose infusion rate was higher with propranolol versus placebo during the hypoglycemic phase (P < 0.05 for both). These results indicate that neither physiological α- nor β-adrenergic blockade attenuates transplanted islet responses to hypoglycemia, suggesting sympathetic reinnervation of the islet graft is not necessary for posttransplant glucose counterregulation.NEW & NOTEWORTHY Whether adrenergic input to islets is necessary for glucose homeostasis in humans is debated. Here, the adrenergic contribution to intrahepatically transplanted islet cell responses to hypoglycemia in individuals with type 1 diabetes was investigated through α- or β-adrenergic receptor blockade during hyperinsulinemic euglycemic-hypoglycemic clamps. Neither α- nor β-adrenergic blockage affected the suppression of endogenous insulin or activation of glucagon secretion, suggesting that sympathetic reinnervation of islet grafts is not required for posttransplant defense against hypoglycemia.

Non-invasive quantification of stem cell-derived islet graft size and composition.

Stem cell-derived islets (SC-islets) are being used as cell replacement therapy for insulin-dependent diabetes. Non-invasive long-term monitoring methods for SC-islet grafts, which are needed to detect misguided differentiation in vivo and to optimise their therapeutic effectiveness, are lacking. Positron emission tomography (PET) has been used to monitor transplanted primary islets. We therefore aimed to apply PET as a non-invasive monitoring method for SC-islet grafts. We implanted different doses of human SC-islets, SC-islets derived using an older protocol or a state-of-the-art protocol and SC-islets genetically rendered hyper- or hypoactive into mouse calf muscle to yield different kinds of grafts. We followed the grafts with PET using two tracers, glucagon-like peptide 1 receptor-binding [18F]F-dibenzocyclooctyne-exendin-4 ([18F]exendin) and the dopamine precursor 6-[18F]fluoro-L-3,4-dihydroxyphenylalanine ([18F]FDOPA), for 5 months, followed by histological assessment of graft size and composition. Additionally, we implanted a kidney subcapsular cohort with different SC-islet doses to assess the connection between C-peptide and stem cell-derived beta cell (SC-beta cell) mass. Small but pure and large but impure grafts were derived from SC-islets. PET imaging allowed detection of SC-islet grafts even <1 mm3 in size, [18F]exendin having a better detection rate than [18F]FDOPA (69% vs 44%, <1 mm3; 96% vs 85%, >1 mm3). Graft volume quantified with [18F]exendin (r2=0.91) and [18F]FDOPA (r2=0.86) strongly correlated with actual graft volume. [18F]exendin PET delineated large cystic structures and its uptake correlated with graft SC-beta cell proportion (r2=0.68). The performance of neither tracer was affected by SC-islet graft hyper- or hypoactivity. C-peptide measurements under fasted or glucose-stimulated conditions did not correlate with SC-islet graft volume or SC-beta cell mass, with C-peptide under hypoglycaemia having a weak correlation with SC-beta cell mass (r2=0.52). [18F]exendin and [18F]FDOPA PET enable non-invasive assessment of SC-islet graft size and aspects of graft composition. These methods could be leveraged for optimising SC-islet cell replacement therapy in diabetes.

A Systematic Review of the Accuracy of Insulin and C-peptide Secretion Ratios During the Oral Glucose Tolerance Test to Diagnose Insulinoma.

Insulinoma is one of the causes of recurrent hypoglycemia, one of the chief complaints for emergency department admission. The gold standard in diagnosing insulinoma is a 72-hour fasting test which is inconvenient and inefficient as it requires hospitalization. Research has found that measurement of insulin and C-peptide during OGTT may help diagnose insulinoma. We aimed to assess the diagnostic value of OGTT in diagnosing insulinoma. The literature search was conducted on 19 August 2022 using several databases (MEDLINE, Scopus, Embase, and ScienceDirect). All studies that measured OGTT as diagnostic tools in diagnosing insulinoma and 72-hour fasting test as reference standard were included. The quality assessment of the selected studies was based on the Centre of Evidence-Based Medicine University of Oxford and the Quality Assessment of Diagnostic Accuracy-2 tool (QUADAS-2). Analysis of the included studies was performed qualitatively. This study was registered on PROSPERO (CRD42022360205). A total of two case-control studies (106 patients) were included, which were at risk of bias and low concern of applicability. Both studies demonstrated that the combination of insulin and C-peptide levels measured during OGTT had high specificity, sensitivity, positive predictive value, and negative predictive value in diagnosing insulinoma compared to the reference standard. A logistic regression model of 8.305 - (0.441 × insulin 2-h/0-h) - (1.679 × C-peptide 1-h/0-h) >0.351 has the highest diagnostic value in one study (AUC 0.97, Sensitivity 86.5%, Specificity 95.2%, PPV 94.1, NPV 88.9). The measurement of 0-h and 2-h insulin and C-peptide levels during 2-h OGTT was found in two small case-control studies with a total of 106 patients to have good sensitivity and specificity. However, due to these limitations, future research is still needed to validate the potential use of OGTT for the diagnosis of insulinoma.

Clinical and Biochemical Features Used to Classify Type-1 and Type-2 Diabetes: A Scoping Review

Abstract The classification of diabetes into type-1 (T1D) and type-2 (T2D) is a critical step in tailoring effective treatment strategies. This distinction relies on a nuanced evaluation of clinical and biochemical features. While age at diagnosis, autoimmune markers, and beta-cell function are among the crucial clinical parameters, biochemical indicators like C-peptide levels and antibody analyses play a pivotal role. This review comprehensively examines the utility of these features in accurately categorizing individuals into T1D and T2D subtypes, providing valuable insights for clinical practice. This scoping review systematically analyses 32 studies aimed at classifying T1D and T2D using various predictor variables. Clinical parameters including family history of diabetes, age at diagnosis, sex, history of insulin use, percent desirable weight or body mass index, waist, and blood pressure emerge as pivotal diagnostic tools. C-peptide measures, encompassing urinary C-peptide to creatinine ratio (UCPCR), and serum fasting and stimulated C-peptide levels further augment classification. Biochemical markers beyond C-peptide, such as serum level of adiponectin, triglycerides (TG), high-density lipoprotein–cholesterol (HDL-C), low-density lipoprotein (LDL-C), Total cholesterol, fasting and postprandial plasma glucose, and glycated hemoglobin (HbA1c), provide supplementary information for classification. Ketonuria and postglucagon or meal-stimulated C-peptide measurements contribute to nuanced classification, particularly in insulin-treated populations. Antibody analyses, particularly presence of GAD65, Zinc Transporter, and IA2 antibodies, highlight the autoimmune nature of T1D. In conclusion, this scoping review underscores the importance of a comprehensive approach that integrates clinical, biochemical, and immunological markers in accurately differentiating between T1D and T2D in clinical practice.

Interlaboratory Comparison of Antibody-Free LC-MS/MS Measurements of C-peptide and Insulin.

The enhanced precision and selectivity of liquid chromatography-tandem mass spectrometry (LC-MS/MS) makes it an attractive alternative to certain clinical immunoassays. Easily transferrable work flows could help facilitate harmonization and ensure high-quality patient care. We aimed to evaluate the interlaboratory comparability of antibody-free multiplexed insulin and C-peptide LC-MS/MS measurements. The laboratories that comprise the Targeted Mass Spectrometry Assays for Diabetes and Obesity Research (TaMADOR) consortium verified the performance of a validated peptide-based assay (reproducibility, linearity, and lower limit of the measuring interval [LLMI]). An interlaboratory comparison study was then performed using shared calibrators, de-identified leftover laboratory samples, and reference materials. During verification, the measurements were precise (2.7% to 3.7%CV), linear (4 to 15 ng/mL for C-peptide and 2 to 14 ng/mL for insulin), and sensitive (LLMI of 0.04 to 0.10 ng/mL for C-peptide and 0.03 ng/mL for insulin). Median imprecision across the 3 laboratories was 13.4% (inter-quartile range [IQR] 11.6%) for C-peptide and 22.2% (IQR 20.9%) for insulin using individual measurements, and 10.8% (IQR 8.7%) and 15.3% (IQR 14.9%) for C-peptide and insulin, respectively, when replicate measurements were averaged. Method comparison with the University of Missouri reference method for C-peptide demonstrated a robust linear correlation with a slope of 1.044 and r2 = 0.99. Our results suggest that combined LC-MS/MS measurements of C-peptide and insulin are robust and adaptable and that standardization with a reference measurement procedure could allow accurate and precise measurements across sites, which could be important to diabetes research and help patient care in the future.

A Prospective 1-Year Follow-up of Glycemic Status and C-Peptide Levels of COVID-19 Survivors with Dysglycemia in Acute COVID-19 Infection.

We evaluated changes in glycemic status, over 1 year, of coronavirus disease 2019 (COVID-19) survivors with dysglycemia in acute COVID-19. COVID-19 survivors who had dysglycemia (defined by glycosylated hemoglobin [HbA1c] 5.7% to 6.4% or random glucose ≥10.0 mmol/L) in acute COVID-19 were recruited from a major COVID-19 treatment center from September to October 2020. Matched non-COVID controls were recruited from community. The 75-g oral glucose tolerance test (OGTT) were performed at baseline (6 weeks after acute COVID-19) and 1 year after acute COVID-19, with HbA1c, insulin and C-peptide measurements. Progression in glycemic status was defined by progression from normoglycemia to prediabetes/diabetes, or prediabetes to diabetes. Fifty-two COVID-19 survivors were recruited. Compared with non-COVID controls, they had higher C-peptide (P< 0.001) and trend towards higher homeostasis model assessment of insulin resistance (P=0.065). Forty-three COVID-19 survivors attended 1-year reassessment. HbA1c increased from 5.5%±0.3% to 5.7%±0.2% (P<0.001), with increases in glucose on OGTT at fasting (P=0.089), 30-minute (P=0.126), 1-hour (P=0.014), and 2-hour (P=0.165). At baseline, 19 subjects had normoglycemia, 23 had prediabetes, and one had diabetes. Over 1 year, 10 subjects (23.8%; of 42 non-diabetes subjects at baseline) had progression in glycemic status. C-peptide levels remained unchanged (P=0.835). Matsuda index decreased (P=0.007) and there was a trend of body mass index increase from 24.4±2.7 kg/m2 to 25.6±5.2 (P=0.083). Subjects with progression in glycemic status had more severe COVID-19 illness than non-progressors (P=0.030). Reassessment was not performed in the control group. Subjects who had dysglycemia in acute COVID-19 were characterized by insulin resistance. Over 1 year, a quarter had progression in glycemic status, especially those with more severe COVID-19. Importantly, there was no significant deterioration in insulin secretory capacity.

Approaches to Measuring Beta Cell Reserve and Defining Partial Clinical Remission in Paediatric Type 1 Diabetes.

Type 1 diabetes (T1D) results from the autoimmune T-cell mediated destruction of pancreatic beta cells leading to insufficient insulin secretion. At the time of diagnosis of T1D, there is residual beta cell function that declines over the subsequent months to years. Recent interventions have been approved to preserve beta cell function in evolving T1D. The aim of this review is to summarise the approaches used to assess residual beta cell function in evolving T1D, and to highlight potential future directions. Studies including subjects aged 0 to 18 years were included in this review. The following search terms were used; "(type 1 diabetes) and (partial remission)" and "(type 1 diabetes) and (honeymoon)". References of included studies were reviewed to determine if additional relevant studies were eligible. There are numerous approaches to quantifying beta cell reserve in evolving T1D. These include c-peptide measurement after a mixed meal or glucagon stimuli, fasting c-peptide, the urinary c-peptide/creatinine ratio, insulin dose-adjusted haemoglobin A1c, and other clinical models to estimate beta cell function. Other biomarkers may have a role, including the proinsulin/c-peptide ratio, cytokines, and microRNA. Studies using thresholds to determine if residual beta cell function is present often differ in values used to define remission. As interventions are approved to preserve beta cell function, it will become increasingly necessary to quantify residual beta cell function in research and clinical contexts. In this report, we have highlighted the strengths and limitations of the current approaches.

Evaluation of endogenous residual insulin secretion by C-peptide measurement

C-peptide measurement allows an estimation of the residual endogenous insulin secretion in diabetic patients. Nowadays plasmatic testing is convenient and unexpensive, but we lack standardized tests. Therefore, there are no official recommendation regarding its use. As an indication, in some circumstances, C-peptide measurement could be used to specify the type of diabetes, help guide the treatment strategy and potentially assess the risk for complications. Its use is still limited and not recommended on a routine base for all patients living with diabetes, but in the future, tests standardization and establishment of reference ranges could give more insight on the clinical relevance of C-peptide measurement.

A high-fat and fructose diet in dogs mirrors insulin resistance and β-cell dysfunction characteristic of impaired glucose tolerance in humans.

This study examined the impact of a hypercaloric high-fat high-fructose diet (HFFD) in dogs as a potential model for human impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM). The HFFD not only led to weight gain but also triggered metabolic alterations akin to the precursors of human T2DM, notably insulin resistance and β-cell dysfunction. Following the HFFD intervention, the dogs exhibited a 50% decrease in insulin sensitivity within the first four weeks, paralleling observations in the progression from normal to IGT in humans. Calculations of the insulinogenic index using both insulin and C-peptide measurements during oral glucose tolerance tests revealed a significant and sustained decrease in early-phase insulin release, with partial compensation in the later phase, predominantly stemming from reduced hepatic insulin clearance. In addition, the Disposition Index, representing the β-cell's capacity to compensate for diminished insulin sensitivity, fell dramatically. These results confirm that a HFFD can instigate metabolic changes in dogs akin to the early stages of progression to T2DM in humans. The study underscores the potential of using dogs subjected to a HFFD as a model organism for studying human IGT and T2DM.

A novel model for predicting diabetes remission after bariatric surgery based on the measurement of C-peptide and creatinine in serum: A pilot study

Background and aimsBariatric surgery is effective for treating type 2 diabetes (T2D) in patients with obesity, although a significant proportion of these patients do not achieve diabetes remission after the surgery even after significant weight loss and metabolic improvement. C-peptide is a valuable marker of beta cell function and insulin secretion, but renal function must be considered when interpreting measurements in patients with T2D. The study aims to investigate the association of serum levels of C-peptide adjusted for creatinine with diabetes remission and glycemic target achievement after bariatric surgery in patients with obesity and T2D. Methods and resultsProspective data from a cohort of 84 patients with obesity and T2D submitted to Roux-en-Y gastric bypass (RYGB) were collected at baseline and at least a 6-month follow up. A multivariate binomial regression model showed that Ln(C-peptide/creatinine) and age were significantly associated with 6-month T2D remission. The area under the curve for the receiver operating characteristic analysis (AUROC) to predict remission was 0.87, and more accurate than the AUROC based on C-peptide levels alone (0.75). The same model was also able to predict achieving an HbA1c target of 7 % (53 mmol/mol) (AUROC 0.96). ConclusionIn conclusion, Ln(C-peptide/creatinine) ratio could be a useful tool in predicting T2D remission and target achievement after RYGB surgery, providing a more accurate reflection of beta cell function in bariatric patients.

Transdermal Blood Sampling for C-Peptide Is a Minimally Invasive, Reliable Alternative to Venous Sampling in Children and Adults With Type 1 Diabetes.

C-peptide and islet autoantibodies are key type 1 diabetes biomarkers, typically requiring venous sampling, which limits their utility. We assessed transdermal capillary blood (TCB) collection as a practical alternative. Ninety-one individuals (71 with type 1 diabetes, 20 control; individuals with type 1 diabetes: aged median 14.8 years [interquartile range (IQR) 9.1-17.1], diabetes duration 4.0 years [1.5-7.7]; control individuals: 42.2 years [38.0-52.1]) underwent contemporaneous venous and TCB sampling for measurement of plasma C-peptide. Participants with type 1 diabetes also provided venous serum and plasma, and TCB plasma for measurement of autoantibodies to glutamate decarboxylase, islet antigen-2, and zinc transporter 8. The ability of TCB plasma to detect significant endogenous insulin secretion (venous C-peptide ≥200 pmol/L) was compared along with agreement in levels, using Bland-Altman. Venous serum was compared with venous and TCB plasma for detection of autoantibodies, using established thresholds. Acceptability was assessed by age-appropriate questionnaire. Transdermal sampling took a mean of 2.35 min (SD 1.49). Median sample volume was 50 µL (IQR 40-50) with 3 of 91 (3.3%) failures, and 13 of 88 (14.7%) <35 µL. TCB C-peptide showed good agreement with venous plasma (mean venous ln[C-peptide] - TCB ln[C-peptide] = 0.008, 95% CI [-0.23, 0.29], with 100% [36 of 36] sensitivity/100% [50 of 50] specificity to detect venous C-peptide ≥200 pmol/L). Where venous serum in multiple autoantibody positive TCB plasma agreed in 22 of 32 (sensitivity 69%), comparative specificity was 35 of 36 (97%). TCB was preferred to venous sampling (type 1 diabetes: 63% vs. 7%; 30% undecided). Transdermal capillary testing for C-peptide is a sensitive, specific, and acceptable alternative to venous sampling; TCB sampling for islet autoantibodies needs further assessment.

One third of cases of new-onset diabetic ketosis in adults are associated with ketosis-prone type 2 diabetes-A systematic review and meta-analysis.

Ketosis-prone type 2 diabetes was defined by the World Health Organization in 2019. According to the literature, the diagnosis is based on the presence of ketosis, islet autoantibody negativity and preserved insulin secretion. Our meta-analysis assessed the prevalence and clinical characteristics of ketosis-prone type 2 diabetes among patients hospitalised with diabetic ketoacidosis (DKA) or ketosis. The systematic search was performed in five main databases as of 15 October 2021 without restrictions. We calculated the pooled prevalence of ketosis-prone type 2 diabetes (exposed group) within the diabetic population under examination, patients with ketoacidosis or ketosis, to identify the clinical characteristics, and we compared it to type 1 diabetes (the comparator group). The random effects model provided pooled estimates as prevalence, odds ratio and mean difference (MD) with 95% confidence intervals. Eleven articles were eligible for meta-analysis, thus incorporating 2010 patients of various ethnic backgrounds. Among patients presenting with DKA or ketosis at the onset of diabetes, 35% (95% CI: 24%-49%) had ketosis-prone type 2 diabetes. These patients were older (MD=11.55years; 95% CI: 5.5-17.6) and had a significantly higher body mass index (BMI) (MD=5.48kg/m2 ; 95% CI: 3.25-7.72) than those with type 1 diabetes. Ketosis-prone type 2 diabetes accounts for one third of DKA or ketosis at the onset of diabetes in adults. These patients are characterised by islet autoantibody negativity and preserved insulin secretion. They are older and have a higher BMI compared with type 1 diabetes. C-peptide and diabetes-related autoantibody measurement is essential to identify this subgroup among patients with ketosis at the onset of diabetes.

SAT087 Maternally Inherited Diabetes And Deafness: Support For SGLT2 Inhibitor Use

Abstract Disclosure: S. Pandya: None. K. Selk: None. Introduction: Maternally inherited diabetes and deafness (MIDD) is a rare genetic disease resulting from a mitochondrial mutation. There is a wide phenotypic expression secondary to heteroplasmy. The clinical manifestations of MIDD are hyperglycemia, sensorineural hearing loss, maculopathy, cardiac conduction defects, myopathy/poor exercise tolerance, and neuropathy. Diabetes mellitus generally occurs during the third decade of life, and there tends to be rapid progression to insulin therapy with reported earlier onset of microvascular complications. Here we present a case of MIDD successfully treated long-term with empagliflozin and linagliptin. Clinical Case: A 36-year-old male with sensorineural hearing loss presented with a 20-pound unintentional weight loss, polyphagia, and polydipsia. His blood glucose level was 300 mg/dL and HbA1c was 14.3%. His mother carried a diagnosis of type 2 diabetes mellitus and his grandmother had latent autoimmune diabetes of adulthood. Prior to presenting to endocrinology, he had been started on metformin, glipizide, and linagliptin with ongoing poor glycemic control. Given his presentation, family history, and lean habitus with BMI of 20, he was assessed for possible autoimmune diabetes. Testing for glutamic acid decarboxylase 65-kilodalton isoform antibody (GAD65), islet cell antibody, tyrosine phosphatase-related islet antigen 2 (IA2), and zinc transporter 8 antibody (ZNT8) was unrevealing. A C-peptide level was detectable but &amp;lt;1 ng/mL. His sulfonylurea was discontinued, and he was started on basal insulin with a dramatic improvement in his glycemic control. He was later able to discontinue insulin therapy. However, given poor exercise tolerance and his known hearing loss, he was seen by genetics where he underwent testing and was found to have a m.3243 A&amp;gt;G mutation in MT-TL1 gene making the diagnosis of MIDD. Metformin was discontinued due to a possible risk of lactic acidosis and sitagliptin was initiated. Due to hyperglycemia, empagliflozin was added and he was later transitioned to empagliflozin-linagliptin to reduce his pill burden. He has continued to have a1c levels of 6.5% or less for the last 3 years and periodic C-peptide measurements have been &amp;gt;1 ng/mL. Conclusion: Given MIDD is a rare form of monogenic diabetes, treatment tends to be individualized with many transitioning to insulin early in their disease course. Given the reported increased risk for microvascular complications, sodium-glucose cotransporter-2 (SGLT2) inhibitors are an attractive therapeutic agent. However, there is little literature on the use of these agents in MIDD and there is concern about the risk for diabetic ketoacidosis given insulin use is required by many afflicted individuals. This case highlights the safety of long-term empagliflozin in a patient with MIDD. Presentation: Saturday, June 17, 2023

Antibodies to Glutamic Acid Decarboxylase-65 is Associated with Total Daily Dose of Insulin Requirement in Children with Type 1 Diabetes

BACKGROUND: Type 1 diabetes (T1D) mostly occurs due to the destruction of pancreatic beta cells due to autoimmune processes. Diagnosis of T1D can be established by examining the c-peptide levels and the markers of pancreatic autoantibodies, including glutamic acid decarboxylase 65 autoantibodies (GAD-65). However, the association between c-peptide and anti-GAD-65 toward patients’ clinical manifestations needs to be further explored. Hence, the aim of current study was to identify the association of anti-GAD65 with c-peptide and clinical characteristics in children with T1D.METHODS: Case-control study involving 47 T1D children (T1D group) and 41 healthy children (control group) younger than 18 years old was conducted. Secondary data regarding subjects’ demographic characteristics and medical history were collected from subjects, and serum blood was drawn from each subject for the anti-GAD65 and c-peptide measurement. Anti-GAD65 and c-peptide levels were measured using an Enzyme-Linked Immunosorbent Assay (ELISA) methods.RESULTS: Anti-GAD65 antibody was detected in 78.7% T1D group, while only 2.43% were detected in control group subject (p=0.0000). The c-peptide level of T1D group was 0.07±0.19 nmol/L and control group was 1.5±0.77 nmol/L (p=0.0000). The total daily dose of insulin in subjects with positive anti-GAD65 was greater than in the negative anti-GAD65 (p=0.012). The sensitivity and specificity of the anti-GAD65 were 85.4% was 66.7%, respectively.CONCLUSION: The results of this study show that anti-GAD65 was associated with total daily dose of insulin requirement in children with T1D.KEYWORDS: diabetes mellitus, type 1 diabetes, anti-GAD65, c-peptide

Intraduodenal nutrient infusion differentially alters intestinal nutrient sensing, appetite, and satiety responses in lean and obese subjects

BackgroundIntestinal nutrient sensing regulates food intake and energy metabolism by acting locally and relaying nutritional status to the brain. It is unclear whether these mechanisms are altered in obese humans. ObjectivesWe aimed to investigate differences in duodenal nutrient sensing in humans with or without obesity and the effects of transiently blocking vagal transmission on nutrient sensing, hunger, and appetite. MethodsIn a single-blinded, randomized, cross-over design, subjects with or without obesity (n = 14 and n = 11, respectively) were infused intraduodenally with saline or a combination of glucose and oleic acid for 90 min (glucose load: 22.5 g, 1 kcal/min; oleic acid load: 10 g, 1 kcal/min) in the presence or absence of local anesthetic (benzocaine). Blood was sampled at 10-min intervals (120–240 min) and 15-min intervals until termination of the study for measurements of gut hormones, insulin, leptin, and C-peptide. Hunger and satiety sensations were scored using the visual analog scale, and hepatic glucose production and glucose oxidation rates were measured. ResultsDuodenal nutrient infusion in lean subjects led to a 65% drop in acyl ghrelin release and robustly increased cholecystokinin 8 (CCK-8) release (65%; P = 0.023); benzocaine infusion delayed this response (2-factor repeated-measures analysis of variance, P = 0.0065). In contrast, subjects with obesity had significantly blunted response to nutrient infusion, and no further effects were observed with benzocaine. Additionally, significant delays were observed in peptide YY (3-36), pancreatic polypeptide, glucose inhibitory peptide, and glucagon-like peptide 1 (7-36) response. No significant interactions were found between body mass index (BMI) or baseline hormone levels and areas under the curve for hormones except CCK-8 (BMI, P = 0.018; baseline CCK, P = 0.013). Nutrient-induced hunger and satiety sensations were impeded by benzocaine only in the lean cohort. Hunger and satiety sensations in subjects with obesity were not responsive to nutrient entry into the duodenum, and no additional effects were observed by blocking neural signaling. ConclusionNutrient-induced gut hormone release and response to transient vagal blockade are significantly blunted in subjects with obesity.This trial was registered at clinicaltrials.org as NCT02537314.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus.

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially. An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association of Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association. Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (Hb A1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of Hb A1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed. The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus.

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially. An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association for Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association. Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (HbA1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of HbA1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed. The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.