The clinical utility of C-peptide measurement in the care of patients with diabetes

Role of Systemic Factors in Improving the Prognosis of Diabetic Retinal Disease and Predicting Response to Diabetic Retinopathy Treatment

Topic

To review clinical evidence on systemic factors that might be relevant to update diabetic retinal disease (DRD) staging systems, including prediction of DRD onset, progression, and response to treatment.

Clinical relevance

Systemic factors may improve new staging systems for DRD to better assess risk of disease worsening and predict response to therapy.

Methods

The Systemic Health Working Group of the Mary Tyler Moore Vision Initiative reviewed systemic factors individually and in multivariate models for prediction of DRD onset or progression (i.e., prognosis) or response to treatments (prediction).

Results

There was consistent evidence for associations of longer diabetes duration, higher glycosylated hemoglobin (HbA1c), and male sex with DRD onset and progression. There is strong trial evidence for the effect of reducing HbA1c and reducing DRD progression. There is strong evidence that higher blood pressure (BP) is a risk factor for DRD incidence and for progression. Pregnancy has been consistently reported to be associated with worsening of DRD but recent studies reflecting modern care standards are lacking. In studies examining multivariate prognostic models of DRD onset, HbA1c and diabetes duration were consistently retained as significant predictors of DRD onset. There was evidence of associations of BP and sex with DRD onset. In multivariate prognostic models examining DRD progression, retinal measures were consistently found to be a significant predictor of DRD with little evidence of any useful marginal increment in prognostic information with the inclusion of systemic risk factor data apart from retinal image data in multivariate models. For predicting the impact of treatment, although there are small studies that quantify prognostic information based on imaging data alone or systemic factors alone, there are currently no large studies that quantify marginal prognostic information within a multivariate model, including both imaging and systemic factors.

Conclusion

With standard imaging techniques and ways of processing images rapidly evolving, an international network of centers is needed to routinely capture systemic health factors simultaneously to retinal images so that gains in prediction increment may be precisely quantified to determine the usefulness of various health factors in the prognosis of DRD and prediction of response to treatment.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Physiological and psychological determinants of long-term diet-induced type 2 diabetes (T2DM) remission: A narrative review

Type 2 diabetes mellitus (T2DM) is a highly prevalent metabolic disease, causing a heavy burden on healthcare systems worldwide, with related complications and anti-diabetes drug prescriptions. Recently, it was demonstrated that T2DM can be put into remission via significant weight loss using low-carbohydrate diets (LCDs) and very low-energy diets (VLEDs) in individuals with overweight and obesity. Clinical trials demonstrated remission rates of 25-77%, and metabolic improvements such as improved blood lipid profile and blood pressure were observed. In contrast, clinical trials showed that remission rate declines with time, concurrent with weight gain, or diminished weight loss. This review aims to discuss existing literature regarding underlying determinants of long-term remission of T2DM including metabolic adaptations to weight loss (e.g., role of gastrointestinal hormones), type of dietary intervention (i.e., LCDs or VLEDs), maintaining beta (β)-cell function, early glycemic control, and psychosocial factors. This narrative review is significant because determining the factors that are associated with challenges in maintaining long-term remission may help in designing sustainable interventions for type 2 diabetes remission.

Phenotypic characterization of nonautoimmune diabetes in adult Ugandans with low body mass index

Background

Type 2 diabetes is common in relatively lean individuals in sub-Saharan Africa. It is unclear whether phenotypic differences exist between underweight and normal-weight African patients with type 2 diabetes. This study compared specific characteristics between underweight (body mass index <18.5 kg/m2) and normal-weight (body mass index of 18.5-24.9 kg/m2) adult Ugandans with new-onset nonautoimmune diabetes.

Methods

We collected the demographic, clinical, anthropometric, and metabolic characteristics of 160 participants with nonobese new-onset type 2 diabetes (defined as diabetes diagnosed <3 months, body mass index <25 kg/m2, and absence of islet-cell autoimmunity). These participants were categorized as underweight and normal weight, and their phenotypic characteristics were compared.

Results

Of the 160 participants with nonobese new-onset type 2 diabetes, 18 participants (11.3%) were underweight. Compared with those with normal weight, underweight participants presented with less co-existing hypertension (5.6% versus 28.2%, p = 0.04) and lower median visceral fat levels [2 (1-3) versus 6 (4-7), p < 0.001], as assessed by bioimpedance analysis. Pathophysiologically, they presented with a lower median 120-min post-glucose load C-peptide level [0.29 (0.13-0.58) versus 0.82 (0.39-1.50) nmol/l, p = 0.04] and a higher prevalence of insulin deficiency (66.7% versus 31.4%, p = 0.003).

Conclusion

This study demonstrates that nonautoimmune diabetes occurs in underweight individuals in sub-Saharan Africa and is characterized by the absence of visceral adiposity, reduced late-phase insulin secretion, and greater insulin deficiency. These findings necessitate further studies to inform how the prevention, identification, and management of diabetes in such individuals can be individualized.

Impact of Platelet-to-HDL-Cholesterol Ratio on Long-Term Mortality in Coronary Artery Disease Patients with or Without Type 2 Diabetes: Insights from a Chinese Multicenter Cohort

Background

Inflammation contributes to the initiation and advancement of both coronary atherosclerosis and type 2 diabetes mellitus (T2DM). Recent evidence has underscored the platelet-to-HDL-cholesterol ratio (PHR) as a promising inflammatory biomarker closely linked to the severity of coronary artery disease (CAD). Nevertheless, the risk of adverse clinical outcomes remains unclear among CAD patients with varying PHR levels and glycemic status.

Methods

A total of 56,316 CAD patients were enrolled, primarily focusing on mortality outcomes. Patients were categorized into four subgroups based on median baseline PHR values and glycemic status: lower PHR (PHR-L) and higher PHR (PHR-H) with or without T2DM. Cox proportional hazard model and subgroup analysis were employed to investigate the association between PHR and glycemic status with mortality.

Results

Over a median 5.32-year follow-up, 8909 (15.8%) patients experienced all-cause mortality, with 3873 (6.9%) deaths attributed to cardiovascular causes. Compared to individuals in PHR-L/non-DM, those in PHR-H/non-DM, PHR-L/DM and PHR-H/DM groups exhibited a higher risk of all-cause death [adjusted hazard ratio (HR) 1.12, 95% confidence interval (CI) 1.06-1.18; HR 1.21, 95% CI 1.14-1.29; HR 1.43, 95% CI 1.34-1.52, respectively], as well as cardiac mortality [HR 1.19, 95% CI 1.08-1.30; HR 1.58, 95% CI 1.44-1.74; HR 1.89, 95% CI 1.72-2.07, respectively]. Cox proportional hazard model also revealed the highest mortality risk among patients in PHR-H/DM compared to other groups (P <0.05). Restricted cubic spline regression analysis revealed a positive linear association between PHR and all-cause as well as cardiac mortality (P for non-linearity >0.05) after adjustment. Additionally, subgroup analysis indicated consistent effects on cardiac mortality within diverse subsets.

Conclusion

In this real-world observational cohort analysis, elevated PHR levels joint with T2DM were related to adverse long-term clinical outcomes in CAD patients. PHR levels may serve as a valuable tool for identifying high-risk individuals within this specific group.

Trial Registration

The Cardiorenal ImprovemeNt II registry NCT05050877.

Atypical Diabetes: What Have We Learned and What Does the Future Hold?

As our understanding of the pathophysiology of diabetes evolves, we increasingly recognize that many patients may have a form of diabetes that does not neatly fit with a diagnosis of either type 1 or type 2 diabetes. The discovery and description of these forms of "atypical diabetes" have led to major contributions to our collective understanding of the basic biology that drives insulin secretion, insulin resistance, and islet autoimmunity. These discoveries now pave the way to a better classification of diabetes based on distinct endotypes. In this review, we highlight the key biological and clinical insights that can be gained from studying known forms of atypical diabetes. Additionally, we provide a framework for identification of patients with atypical diabetes based on their clinical, metabolic, and molecular features. Helpful clinical and genetic resources for evaluating patients suspected of having atypical diabetes are provided. Therefore, appreciating the various endotypes associated with atypical diabetes will enhance diagnostic accuracy and facilitate targeted treatment decisions.

Copper Deficiency Associated with Glycemic Control in Individuals with Type 2 Diabetes Mellitus

Adequate copper (Cu) status has been associated with improved glycemic control, partly because of its role in reducing oxidative stress through superoxide dismutase (SOD) activity. Thus, the aim was to investigate the relationship between plasma Cu concentration and markers associated with glycemic control in individuals with type 2 diabetes mellitus (T2DM). This observational and cross-sectional study was conducted in individuals with T2DM of both sexes, aged between 19 and 59 years. Plasma Cu levels were analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). Fasting glucose and insulin concentrations, C-peptide levels, SOD activity, and glycated hemoglobin (%HbA1c) were measured. Homeostatic model assessments (HOMA%B, HOMA%S, and HOMA-IR) were also performed. Additionally, %body fat and waist circumference were measured, and body mass index was calculated. Participants were categorized based on their plasma Cu concentrations (< 70 µg/dL and ≥ 70 µg/dL). The associations between variables were analyzed using chi-squared or Fisher's test and binary logistic regression models. Statistical significance was set at P < 0.05. Of the 97 participants (74.2% women), 85.5% had Cu deficiency. Cu-deficient individuals showed elevated C-peptide concentrations and HOMA%B values compared to those with adequate Cu levels (2.8 ng/mL vs. 1.8 ng/mL, P = 0.011; and 71.4 vs. 31.0, P = 0.003), respectively. Cu deficiency was associated with insulin resistance (P = 0.044) and decreased likelihood of exceeding the target serum glucose level (OR = 0.147, P = 0.013). However, no significant association was found between SOD activity and plasma Cu concentration. Consequently, Cu deficiency was linked to improved glycemic control, although it was not associated with the other markers.

Predictive value of postprandial C-peptide for utilizing multiple daily injection therapy in type 2 diabetes

PURPOSE

Multiple daily injection (MDI) insulin therapy is an effective method of glycemic control and appropriate assignment to MDI therapy could minimize the risks of hypoglycemia and weight gain. The aim of the present study was to identify factors associated with indication for MDI therapy in type 2 diabetes (T2DM).

METHODS

We recruited 360 participants with T2DM that were admitted to the Endocrinology Department of Peking University People's Hospital between August 2017 and July 2018. They first underwent intensive insulin therapy, then were switched to an optimized, simpler insulin treatment that aimed to maintain fasting blood glucose between 4.4 and 7.2 mmol/L, without episodes of hypoglycemia. The baseline characteristics of groups administering either MDI or basal/premix insulin were compared and multivariable logistic regression analysis was used to determine the odds ratios (ORs) for factors associated with MDI therapy. Receiver operating characteristic (ROC) curves were then used to identify independent predictors of MDI insulin regimen efficacy.

RESULTS

The mean age of the participants was 57.6 ± 12.9 years, and diabetes duration was 14.2 ± 8.2 years. Two hundred and sixty-seven participants administered basal/premix insulin and 93 underwent MDI therapy, of whom 61.8% and 46.2% were male, respectively (p = 0.01). The duration of diabetes was significantly longer in the MDI group (13.1 ± 7.7 years vs. 17.3 ± 8.7 years; p < 0.01). Fasting plasma glucose (FPG) was higher in the MDI group than in the basal/premix group (8.3 [6.7, 11.3] mmol/L vs. 7.2 [5.7, 9.3] mmol/L; p < 0.01), while the postprandial C-peptide concentration (PCP) was significantly lower in the MDI group (2.6 [1.8, 3.5] ng/mL) compared to the basal/premix group (3.6 [2.5, 6.2] ng/mL, p < 0.01. Multivariable logistic regression analysis suggested that diabetes duration and FPG were positively associated with MDI therapy: OR (95% confidence interval [CI]) 1.06 (1.02, 1.10) and 1.12 (1.02, 1.24), respectively. In addition, PCP was negatively associated with MDI therapy (0.72 [0.60, 0.86]). ROC analysis suggested that a PCP of < 3.1 ng/mL predicted MDI therapy with 59.6% sensitivity and 72.1% specificity.

CONCLUSION

The results of our study suggest that longer diabetes duration, higher FPG, and lower PCP were associated with necessity for MDI insulin regimen. These findings should assist with the personalization of insulin treatment.

Infection with SARS-CoV-2 can cause pancreatic impairment

Evidence suggests associations between COVID-19 patients or vaccines and glycometabolic dysfunction and an even higher risk of the occurrence of diabetes. Herein, we retrospectively analyzed pancreatic lesions in autopsy tissues from 67 SARS-CoV-2 infected non-human primates (NHPs) models and 121 vaccinated and infected NHPs from 2020 to 2023 and COVID-19 patients. Multi-label immunofluorescence revealed direct infection of both exocrine and endocrine pancreatic cells by the virus in NHPs and humans. Minor and limited phenotypic and histopathological changes were observed in adult models. Systemic proteomics and metabolomics results indicated metabolic disorders, mainly enriched in insulin resistance pathways, in infected adult NHPs, along with elevated fasting C-peptide and C-peptide/glucose ratio levels. Furthermore, in elder COVID-19 NHPs, SARS-CoV-2 infection causes loss of beta (β) cells and lower expressed-insulin in situ characterized by islet amyloidosis and necrosis, activation of α-SMA and aggravated fibrosis consisting of lower collagen in serum, an increase of pancreatic inflammation and stress markers, ICAM-1 and G3BP1, along with more severe glycometabolic dysfunction. In contrast, vaccination maintained glucose homeostasis by activating insulin receptor α and insulin receptor β. Overall, the cumulative risk of diabetes post-COVID-19 is closely tied to age, suggesting more attention should be paid to blood sugar management in elderly COVID-19 patients.

Performance of European prediction models for classification of type 1 and type 2 diabetes in Indians

AIM

We aimed to determine the performance of European prediction models in an Indian population to classify type 1 diabetes(T1D) and type 2 diabetes(T2D).

METHODS

We assessed discrimination and calibration of published models of diabetes classification, using retrospective data from electronic medical records of 83309 participants aged 18-50 years living in India. Diabetes type was defined based on C-peptide measurement and early insulin requirement. Models assessed combinations of clinical measurements: age at diagnosis, body mass index(mean = 26.6 kg/m2), sex(male = 64.9 %), Glutamic acid decarboxylase(GAD) antibody, serum cholesterol, serum triglycerides, and high-density lipoprotein(HDL) cholesterol.

RESULTS

67955 participants met inclusion criteria, of whom 0.8 % had T1D, which was markedly lower than model development cohorts. Model discrimination for clinical features was broadly similar in our Indian cohort compared to the European cohort: area under the receiver operating characteristic curve(AUC ROC) was 0.90 vs. 0.90 respectively, but was lower in the subset of young participants with measured GAD antibodies(n = 2404): and an AUC ROC of 0.87 when clinical features, sex, lipids and GAD antibodies were combined. All models substantially overestimated the likelihood of T1D, reflecting the lower prevalence of T1D in the Indian population. However, good model performance was achieved after recalibration by updating the model intercept and slope.

CONCLUSION

Models for diabetes classification maintain the discrimination of T1D and T2D in this Indian population, where T2D is far more common, but require recalibration to obtain appropriate model probabilities. External validation and recalibration are needed before these tools can be used in non-European populations.

Future clinical prospects of C-peptide testing in the early diagnosis of gestational diabetes

Gestational diabetes is typically diagnosed in the late second or third trimester of pregnancy. It is one of the most common metabolic disorders among expectant mothers, with potential serious short- and long-term complications for both maternal and offspring health. C-peptide is secreted from pancreatic beta-cells into circulation in equimolar amounts with insulin. It is a useful biomarker to estimate the beta-cell function because it undergoes negligible hepatic clearance and consequently it has a longer half-life compared to insulin. Pregnancy induces increased insulin resistance due to physiological changes in hormonal and metabolic homeostasis. Inadequate compensation by islet beta-cells results in hyperglycemia. The standard oral glucose tolerance test at 24-28 wk of gestation sets the diagnosis. Accumulated evidence from prospective studies indicates a link between early pregnancy C-peptide levels and the risk of subsequent gestational diabetes. Elevated C-peptide levels and surrogate glycemic indices at the beginning of pregnancy could prompt appropriate strategies for secondary prevention.

High Prevalence of A-β+ Ketosis-Prone Diabetes in Children with Type 2 Diabetes and Diabetic Ketoacidosis at Diagnosis: Evidence from the Rare and Atypical Diabetes Network (RADIANT)

Background

A-β+ ketosis-prone diabetes (KPD) in adults is characterized by presentation with diabetic ketoacidosis (DKA), negative islet autoantibodies, and preserved β-cell function in persons with a phenotype of obesity-associated type 2 diabetes (T2D). The prevalence of KPD has not been evaluated in children. We investigated children with DKA at "T2D" onset and determined the prevalence and characteristics of pediatric A-β+ KPD within this cohort.

Methods

We reviewed the records of 716 children with T2D at a large academic hospital and compared clinical characteristics of those with and without DKA at onset. In the latter group, we identified patients with A-β+ KPD using criteria of the Rare and Atypical Diabetes Network (RADIANT) and defined its prevalence and characteristics.

Results

Mean age at diagnosis was 13.7 ± 2.4 years: 63% female; 59% Hispanic, 29% African American, 9% non-Hispanic White, and 3% other. Fifty-six (7.8%) presented with DKA at diagnosis and lacked islet autoantibodies. Children presenting with DKA were older and had lower C-peptide and higher glucose concentrations than those without DKA. Twenty-five children with DKA (45%) met RADIANT A-β+ KPD criteria. They were predominantly male (64%), African American or Hispanic (96%), with substantial C-peptide (1.3 ± 0.7 ng/mL) at presentation with DKA and excellent long-term glycemic control (HbA1c 6.6% ± 1.9% at follow-up (median 1.3 years postdiagnosis)).

Conclusions

In children with a clinical phenotype of T2D and DKA at diagnosis, approximately half meet criteria for A-β+ KPD. They manifest the key characteristics of obesity, preserved β-cell function, male predominance, and potential to discontinue insulin therapy, similar to adults with A-β+ KPD.

C-peptide Level in Patients With Uncontrolled Type 2 Diabetes Mellitus on Oral Anti-diabetic Drugs

BACKGROUND

In the development and progression of type 2 diabetes mellitus, β-cell dysfunction occurs after insulin resistance. Despite poor glycaemic control, there is a practice of increasing the dose of oral anti-diabetics or adding more drugs to the regimen due to the common perception that low endogenous insulin secretion is related to type 1 diabetes mellitus only and patient's poor compliance to injectables. Keeping this perspective in mind, this study was conducted to assess the prevalence of beta cell dysfunction by low serum C-peptide levels and its correlation with poor glycaemic control.

MATERIALS AND METHODS

A total of 134 patients with type 2 diabetes mellitus for more than 10 years on oral anti-diabetic drugs fulfilling our eligibility criteria were enrolled in our study. Blood samples for fasting blood sugar and fasting C-peptide level were taken before breakfast and uptake of anti-diabetic drugs. Correlation analysis was performed to evaluate the relationship between fasting C-peptide and glycaemic control with respect to glycated haemoglobin (HbA1c).

RESULTS

Of the patients, 19.40% had insufficient beta cell reserve serum levels (C-peptide < 0.5 ng/ml), of which most of the patients (14/26 = 53.85%) had poor glycaemic control (HbA1c < 8.0%). Overall, there was a significant correlation between poor glycaemic control with respect to HbA1c and low serum C-peptide levels (p < 0.05). We found a significant association of beta cell dysfunction (low fasting C-peptide level) with the use of insulin secretagogue. The proportion of patients with C-peptide levels less than 0.5 ng/ml was lower in patients using sodium-glucose cotransporter-2 (SGLT-2) inhibitors as compared to insulin secretagogue.

CONCLUSION

SGLT-2 inhibitors should be preferred over other anti-diabetic drugs as an add-on to existing metformin therapy. Insulin requirement must be assessed in patients who have long-term type 2 diabetes mellitus.

Diabetes Study of Children of Diverse Ethnicity and Race: Study design

AIMS

Determining diabetes type in children has become increasingly difficult due to an overlap in typical characteristics between type 1 diabetes (T1D) and type 2 diabetes (T2D). The Diabetes Study in Children of Diverse Ethnicity and Race (DISCOVER) programme is a National Institutes of Health (NIH)-supported multicenter, prospective, observational study that enrols children and adolescents with non-secondary diabetes. The primary aim of the study was to develop improved models to differentiate between T1D and T2D in diverse youth.

MATERIALS AND METHODS

The proposed models will evaluate the utility of three existing T1D genetic risk scores in combination with data on islet autoantibodies and other parameters typically available at the time of diabetes onset. Low non-fasting serum C-peptide (<0.6 nmol/L) between 3 and 10 years after diabetes diagnosis will be considered a biomarker for T1D as it reflects the loss of insulin secretion ability. Participating centres are enrolling youth (<19 years old) either with established diabetes (duration 3-10 years) for a cross-sectional evaluation or with recent onset diabetes (duration 3 weeks-15 months) for the longitudinal observation with annual visits for 3 years. Cross-sectional data will be used to develop models. Longitudinal data will be used to externally validate the best-fitting model.

RESULTS

The results are expected to improve the ability to classify diabetes type in a large and growing subset of children who have an unclear form of diabetes at diagnosis.

CONCLUSIONS

Accurate and timely classification of diabetes type will help establish the correct clinical management early in the course of the disease.

Use of a type 1 genetic risk score for classification of diabetes type in young Australian adults: the Fremantle Diabetes Study Phase II

The applicability of a UK-validated genetic risk score (GRS) was assessed in 158 participants in the Fremantle Diabetes Study Phase II diagnosed between 20 and <40 years of age with type 1 or type 2 diabetes or latent autoimmune diabetes of adults (LADA). For type 1 versus type 2/LADA, the area under the receiver operating characteristic curve (AUC) was highest for serum C-peptide (0.93) and lowest for the GRS (0.66). Adding age at diagnosis and body mass index to C-peptide increased the AUC minimally (0.96). The GRS appears of modest diabetes diagnostic value in young Australians.

Classification of type 1 diabetes: A pathogenic and treatment-based classification

AIM

To improve the diagnosis and classification of patients who fail to satisfy current type 1 diabetes diagnostic criteria.

METHODS

Review of the literature and current diagnostic guidelines.

DISCUSSION

We propose a novel, clinically useful classification based on islet autoantibody status and non-fasting C-peptide levels. Notably, we discuss the subgroup of latent autoimmune diabetes in the young and propose a new subgroup classification of autoantibody negative type 1 diabetes in remission.

CONCLUSION

A novel classification system is proposed. Further work is needed to accurately diagnose and manage minority type 1 diabetes subgroups.

Oral gavage delivery of Cornus officinalis extract delays type 1 diabetes onset and hyperglycemia in non-obese diabetic (NOD) mice

Type 1 diabetes (T1D) is an autoimmune disease initiated by genetic predisposition and environmental influences, which result in the specific destruction of insulin-producing pancreatic β-cells. Currently, there are over 1.6 million cases of T1D in the United States with a worldwide incidence rate that has been increasing since 1990. Here, we examined the effect of Cornus officinalis (CO), a well-known ethnopharmacological agent, on a T1D model of the non-obese diabetic (NOD) mouse. A measured dose of CO extract was delivered into 10-week-old NOD mice by oral gavage for 15 weeks. T1D incidence and hyperglycemia were significantly lower in the CO-treated group as compared to the water gavage (WT) and a no handling or treatment control group (NHT) following treatment. T1D onset per group was 30%, 60% and 86% for the CO, WT and NHT groups, respectively. Circulating C-peptide was higher, and pancreatic insulitis was decreased in non-T1D CO-treated mice. Our findings suggest that CO may have therapeutic potential as both a safe and effective interventional agent to slow early stage T1D progression.

High Frequency of Recessive WFS1 Mutations Among Indian Children With Islet Antibody-negative Type 1 Diabetes

BACKGROUND

While the frequency of islet antibody-negative (idiopathic) type 1 diabetes mellitus (T1DM) is reported to be increased in Indian children, its aetiology has not been studied. We investigated the role of monogenic diabetes in the causation of islet antibody-negative T1DM.

METHODS

We conducted a multicenter, prospective, observational study of 169 Indian children (age 1-18 years) with recent-onset T1DM. All were tested for antibodies against GAD65, islet antigen-2, and zinc transporter 8 using validated ELISA. Thirty-four islet antibody-negative children underwent targeted next-generation sequencing for 31 genes implicated in monogenic diabetes using the Illumina platform. All mutations were confirmed by Sanger sequencing.

RESULTS

Thirty-five (21%) children were negative for all islet antibodies. Twelve patients (7% of entire cohort, 34% of patients with islet antibody-negative T1DM) were detected to have pathogenic or likely pathogenic genetic variants. The most frequently affected locus was WFS1, with 9 patients (5% of entire cohort, 26% of islet antibody-negative). These included 7 children with homozygous and 1 patient each with a compound heterozygous and heterozygous mutation. Children with Wolfram syndrome 1 (WS) presented with severe insulin-requiring diabetes (including 3 patients with ketoacidosis), but other syndromic manifestations were not detected. In 3 patients, heterozygous mutations in HNF4A, ABCC8, and PTF1A loci were detected.

CONCLUSION

Nearly one-quarter of Indian children with islet antibody-negative T1DM had recessive mutations in the WFS1 gene. These patients did not exhibit other features of WS at the time of diagnosis. Testing for monogenic diabetes, especially WS, should be considered in Indian children with antibody-negative T1DM.

Use of probiotics and similar in pediatric patients with Type 1 Diabetes Mellitus: a systematic review

OBJECTIVE

To perform a systematic review of randomized controlled trials, evaluating the effect of probiotics, prebiotics or symbiotics supplementation on glycemic and inflammatory control in children with Type 1 Diabetes Mellitus (T1DM).

DATA SOURCE

The Medical Literature Analysis and Retrieval System Online (MEDLINE/PubMed), Clinical Trials, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) and Scientific Electronic Library Online (SciELO) databases were searched. Randomized clinical trials of pediatric patients with DM1 using probiotics, prebiotics or symbiotics were included, regardless of year or language of publication. Studies that did not evaluate glycated hemoglobin (HbA1c) were excluded. Metabolic results (HbA1c, total insulin dose and C-peptide) and inflammatory control [interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ)] during probiotic supplementation or similar, related to modification of the intestinal microbiota, were analyzed. PROSPERO ID: CRD42022384485.

DATA SYNTHESIS

Five studies were selected for a systematic review. Regarding metabolic markers, only one of the articles that analyzed HbA1c showed a significant decrease (p=0.03) in the intervention group. One study identified a reduction in the total dose of insulin and increased C-peptide levels. Regarding the evaluation of inflammatory parameters (IL-10, TNF-α, INF-γ), there were no statistical relevant modifications.

CONCLUSIONS

Current data from the literature were not conclusive in identifying an improvement in glycemic control and did not observe changes in inflammatory parameters with the use of probiotics, prebiotics or symbiotics in pediatric patients with T1DM.

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

CONTEXT

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.

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Effect of Serum C-Peptide Levels on the Development of Contrast-Induced Nephropathy in Diabetic Patients Undergoing Coronary Angiography

Contrast-induced nephropathy (CIN) is an important cause of morbidity and mortality, in patients with diabetes who undergo coronary angiography (CAG). It is known that serum C-peptide has renoprotective effects in diabetic nephropathy. Patients with diabetes (n = 552) who underwent CAG in our center between January 2020 and December 2021 were included, retrospectively. The patients were divided into 2 groups: not-developing CIN (group 1) and developing CIN (group 2). CIN developed in 128 (23.1%) of the patients with diabetes who underwent CAG. C-peptide, albumin, hemoglobin, hematocrit, initial creatinine, ejection fraction (EF), were significantly lower in the group that developed CIN compared with the group that did not (P < .05, for all). In correlation analysis, creatinine increase rate (ΔCr) was negatively correlated with C-peptide, hematocrit, and ejection fraction (r = -.241, P < .001; r = -.135, P < .001; r = -.194, P = .001; respectively). In logistic regression analysis, C-peptide level (Odds Ratio: .404, 95% Confidence Interval: .286-.571, P < .001) was an independent predictor of CIN. In the present study, C-peptide level was an independent predictor of CIN in patients with diabetes. This study suggests that low levels of C-peptide are associated with a greater risk of CIN.

Empagliflozin Normalizes Fasting Hyperglycemia and Improves Postprandial Glucose Tolerance in Totally Pancreatectomized Patients: A Randomized, Double-Blind, Placebo-Controlled Crossover Study

OBJECTIVE

Insulin remains the only glucose-lowering treatment modality recommended for totally pancreatectomized patients. We investigated the effects of the sodium-glucose cotransporter 2 inhibitor empagliflozin on fasting and postprandial glucose concentrations in pancreatectomized patients and matched healthy control participants.

RESEARCH DESIGN AND METHODS

In a randomized, double-blind, placebo-controlled crossover study, 10 pancreatectomized patients and 10 matched control participants underwent two 3-h liquid mixed meal tests preceded by two doses of 25 mg empagliflozin (administered the night before and in the morning of the meal test) or placebo, respectively. Basal insulin was administered as usual, but bolus insulin was omitted before the meal test during experimental days.

RESULTS

Compared with placebo, empagliflozin lowered fasting plasma glucose (5.0 ± 0.4 vs. 7.9 ± 0.9 mmol/L [mean ± SEM], P = 0.007) and postprandial plasma glucose excursions as assessed by baseline-subtracted area under the curve (1,080 [733; 1,231] vs. 1,169 [1,036; 1,417] pmol/L × min [median (25th and 75th percentiles)], P = 0.014) in the pancreatectomized patients. In the control participants, empagliflozin lowered fasting plasma glucose compared with placebo (5.1 ± 0.1 vs. 5.5 ± 0.1 mmol/L, P = 0.008) without affecting postprandial glucose excursions significantly. The pancreatomy group exhibited greater postprandial glucagon excursions compared with the control group on both experimental days (P ≤ 0.015); no within-group differences between days were observed.

CONCLUSIONS

Empagliflozin administered the day before and immediately before a standardized liquid mixed meal test normalized fasting hyperglycemia and improved postprandial glucose tolerance in pancreatectomized patients.

Pregnancy induces longitudinal changes in urinary C-peptide creatinine ratio in women with type 1 diabetes

AIMS

Changes in maternal serum C-peptide have been described during pregnancy in women with Type 1 diabetes. We aimed to determine whether in these women, C-peptide, as measured by the urinary C-peptide creatinine ratio (UCPCR), display changes during the course of pregnancy and in the postpartum period.

METHODS

In this longitudinal study including 26 women, UCPCR was measured in the first, second, and third trimester of pregnancy, and postpartum, using a high sensitivity two-step chemiluminescent microparticle immunoassay.

RESULTS

UCPCR was detectable in 7/26 (26.9%) participants in the first trimester, 10/26 (38.4%) in the second trimester, and 18/26 (69.2%) in the third trimester. Changes in UCPCR concentrations were observed throughout pregnancy, significantly increasing from first to third trimester. UCPCR concentration in the three trimesters was associated with a shorter duration of diabetes and in the third trimester also with first trimester UCPCR.

CONCLUSION

UCPCR detects longitudinal changes during pregnancy in women with type 1 diabetes mellitus, more marked in those with shorter diabetes duration.

Relations between Glucose and d-Amino Acids in the Modulation of Biochemical and Functional Properties of Rodent Islets of Langerhans

The cell-to-cell signaling role of d-amino acids (d-AAs) in the mammalian endocrine system, particularly in the islets of Langerhans, has drawn growing interest for their potential involvement in modulating glucose metabolism. Previous studies found colocalization of serine racemase [produces d-serine (d-Ser)] and d-alanine (d-Ala) within insulin-secreting beta cells and d-aspartate (d-Asp) within glucagon-secreting alpha cells. Expressed in the islets, functional N-methyl-d-aspartate receptors are involved in the modulation of glucose-stimulated insulin secretion and have binding sites for several d-AAs. However, knowledge of the regulation of d-AA levels in the islets during glucose stimulation as well as the response of islets to different levels of extracellular d-AAs is limited. In this study, we determined the intracellular and extracellular levels of d-Ser, d-Ala, and d-Asp in cultures of isolated rodent islets exposed to different levels of extracellular glucose. We found that the intracellular levels of the enantiomers demonstrated large variability and, in general, were not affected by extracellular glucose levels. However, significantly lower levels of extracellular d-Ser and d-Ala were observed in the islet media supplemented with 20 mM concentration of glucose compared to the control condition utilizing 3 mM glucose. Glucose-induced oscillations of intracellular free calcium concentration ([Ca2+]i), a proxy for insulin secretion, were modulated by the exogenous application of d-Ser and d-Ala but not by their l-stereoisomers. Our results provide new insights into the roles of d-AAs in the biochemistry and function of pancreatic islets.

Quantifying beta cell function in the preclinical stages of type 1 diabetes

Clinically symptomatic type 1 diabetes (stage 3 type 1 diabetes) is preceded by a pre-symptomatic phase, characterised by progressive loss of functional beta cell mass after the onset of islet autoimmunity, with (stage 2) or without (stage 1) measurable changes in glucose profile during an OGTT. Identifying metabolic tests that can longitudinally track changes in beta cell function is of pivotal importance to track disease progression and measure the effect of disease-modifying interventions. In this review we describe the metabolic changes that occur in the early pre-symptomatic stages of type 1 diabetes with respect to both insulin secretion and insulin sensitivity, as well as the measurable outcomes that can be derived from the available tests. We also discuss the use of metabolic modelling to identify insulin secretion and sensitivity, and the measurable changes during dynamic tests such as the OGTT. Finally, we review the role of risk indices and minimally invasive measures such as those derived from the use of continuous glucose monitoring.

The challenges of identifying and studying type 1 diabetes in adults

Diagnosing type 1 diabetes in adults is difficult since type 2 diabetes is the predominant diabetes type, particularly with an older age of onset (approximately >30 years). Misclassification of type 1 diabetes in adults is therefore common and will impact both individual patient management and the reported features of clinically classified cohorts. In this article, we discuss the challenges associated with correctly identifying adult-onset type 1 diabetes and the implications of these challenges for clinical practice and research. We discuss how many of the reported differences in the characteristics of autoimmune/type 1 diabetes with increasing age of diagnosis are likely explained by the inadvertent study of mixed populations with and without autoimmune aetiology diabetes. We show that when type 1 diabetes is defined by high-specificity methods, clinical presentation, islet-autoantibody positivity, genetic predisposition and progression of C-peptide loss remain broadly similar and severe at all ages and are unaffected by onset age within adults. Recent clinical guidance recommends routine islet-autoantibody testing when type 1 diabetes is clinically suspected or in the context of rapid progression to insulin therapy after a diagnosis of type 2 diabetes. In this moderate or high prior-probability setting, a positive islet-autoantibody test will usually confirm autoimmune aetiology (type 1 diabetes). We argue that islet-autoantibody testing of those with apparent type 2 diabetes should not be routinely undertaken as, in this low prior-prevalence setting, the positive predictive value of a single-positive islet antibody for autoimmune aetiology diabetes will be modest. When studying diabetes, extremely high-specificity approaches are needed to identify autoimmune diabetes in adults, with the optimal approach depending on the research question. We believe that until these recommendations are widely adopted by researchers, the true phenotype of late-onset type 1 diabetes will remain largely misunderstood.

C-peptide and metabolic outcomes in trials of disease modifying therapy in new-onset type 1 diabetes: an individual participant meta-analysis

BACKGROUND

Metabolic outcomes in type 1 diabetes remain suboptimal. Disease modifying therapy to prevent β-cell loss presents an alternative treatment framework but the effect on metabolic outcomes is unclear. We, therefore, aimed to define the relationship between insulin C-peptide as a marker of β-cell function and metabolic outcomes in new-onset type 1 diabetes.

METHODS

21 trials of disease-modifying interventions within 100 days of type 1 diabetes diagnosis comprising 1315 adults (ie, those 18 years and older) and 1396 children (ie, those younger than 18 years) were combined. Endpoints assessed were stimulated area under the curve C-peptide, HbA1c, insulin use, hypoglycaemic events, and composite scores (such as insulin dose adjusted A1c, total daily insulin, U/kg per day, and BETA-2 score). Positive studies were defined as those meeting their primary endpoint. Differences in outcomes between active and control groups were assessed using the Wilcoxon rank test.

FINDINGS

6 months after treatment, a 24·8% greater C-peptide preservation in positive studies was associated with a 0·55% lower HbA1c (p<0·0001), with differences being detectable as early as 3 months. Cross-sectional analysis, combining positive and negative studies, was consistent with this proportionality: a 55% improvement in C-peptide preservation was associated with 0·64% lower HbA1c (p<0·0001). Higher initial C-peptide levels and greater preservation were associated with greater improvement in HbA1c. For HbA1c, IDAAC, and BETA-2 score, sample size predictions indicated that 2-3 times as many participants per group would be required to show a difference at 6 months as compared with C-peptide. Detecting a reduction in hypoglycaemia was affected by reporting methods.

INTERPRETATION

Interventions that preserve β-cell function are effective at improving metabolic outcomes in new-onset type 1 diabetes, confirming their potential as adjuncts to insulin. We have shown that improvements in HbA1c are directly proportional to the degree of C-peptide preservation, quantifying this relationship, and supporting the use of C-peptides as a surrogate endpoint in clinical trials.

FUNDING

JDRF and Diabetes UK.

Oral glucose sensing in cephalic phase insulin release

Oral stimulation with foods or food components elicits cephalic phase insulin release (CPIR), which limits postprandial hyperglycemia. Despite its physiological importance, the specific gustatory mechanisms that elicit CPIR have not been clearly defined. While most studies point to glucose and glucose-containing saccharides (e.g., sucrose, maltodextrins) as being the most consistent elicitors, it is not apparent whether this is due to the detection of glucose per se, or to the perceived taste cues associated with these stimuli (e.g., sweetness, starchiness). This study investigated potential sensory mechanisms involved with eliciting CPIR in humans, focusing on the role of oral glucose detection and associated taste. Four stimulus conditions possessing different carbohydrate and taste profiles were designed: 1) glucose alone; 2) glucose mixed with lactisole, a sweet taste inhibitor; 3) maltodextrin, which is digested to starchy- and sweet-tasting products during oral processing; and 4) maltodextrin mixed with lactisole and acarbose, an oral digestion inhibitor. Healthy adults (N = 22) attended four sessions where blood samples were drawn before and after oral stimulation with one of the target stimuli. Plasma c-peptide, insulin, and glucose concentrations were then analyzed. Whereas glucose alone elicited CPIR (one-sample t-test, p < 0.05), it did not stimulate the response in the presence of lactisole. Likewise, maltodextrin alone stimulated CPIR (p < 0.05), but maltodextrin with lactisole and acarbose did not. Together, these findings indicate that glucose is an effective CPIR stimulus, but that an associated taste sensation also serves as an important cue for triggering this response in humans.

Insulinemic potential of diet and psychological disorders: A cross-sectional, population-based study

BACKGROUND

Serum insulin levels and insulin sensitivity can impact mental disorders. This study investigates the association of the insulinemic potential of diet calculated using the empirical dietary indices for insulin resistance (EDIR) and hyperinsulinemia (EDIH) with psychological disorders, including depression, anxiety, and stress.

METHODS

This cross-sectional study was undertaken on 5405 individuals, aged 20-70, from the Yazd Health Study (YaHS). The food frequency questionnaire (FFQ) was used to collect dietary intakes. EDIR and EDIH were calculated from the FFQ data. Psychological disorders were assessed by an Iranian-validated version of the depression, anxiety, and stress scale questionnaire 21 (DASS 21). Multivariable logistic regression analysis was performed and odds ratio (OR) and 95 % confidence interval (CI) were reported.

RESULTS

The mean ± SD of EDIR and EDIH were 0.32 ± 0.17 and 0.11 ± 0.08 in the total population, respectively. In the final adjusted model, participants in the highest versus the lowest quartile of EDIR had statistically higher odds of depression (OR: 1.28; 95 % CI: 1.01-1.62, P-trend = 0.032). However, no statistically significant association was observed between the EDIH score and depression. Also, EDIR and EDIH scores were not significantly associated with the odds of anxiety and stress.

LIMITATIONS

The cross-sectional design of the study prevented the inference of causality.

CONCLUSIONS

Higher adherence to EDIR was positively associated with depression, but there was no significant association between EDIH and depression. EDIR and EDIH were also not significantly related to anxiety or stress.

The HbA1c/C-Peptide Ratio is Associated With the No-Reflow Phenomenon in Patients With ST-Elevation Myocardial Infarction

Currently, the gold standard treatment for ST-elevation myocardial infarction (STEMI) is primary percutaneous coronary intervention (pPCI), but even after successful pPCI, a perfusion disorder in the epicardial coronary arteries, termed no-reflow phenomenon (NR), can develop, resulting in short- and long-term adverse events. The present study assessed the relationship between NR and HbA1c/C-peptide ratio (HCR) in 1834 consecutive patients who underwent pPCI due to STEMI. Participants were divided into two groups according to NR status and the demographic, clinical and periprocedural characteristics of the groups were compared. NR developed in 352 (19.1%) of the patients in the study. While C-peptide levels were significantly lower in the NR group, HbA1c and HCR were significantly higher (P < .001, for all). In multivariable analysis, C-peptide, HbA1c, and HCR, were determined as independent predictors for NR (P < .05, for all). In Receiver Operating Characteristic (ROC) analysis, HCR predicted the NR with 80% specificity and 77% sensitivity. In STEMI patients, combining HbA1c and C-peptide in a single fraction has a predictive value for NR independent of diabetes. This ratio may contribute to risk stratification of STEMI patients.

A Critical Analysis of the FDA's Omics-Driven Pharmacodynamic Biomarkers to Establish Biosimilarity

Demonstrating biosimilarity entails comprehensive analytical assessment, clinical pharmacology profiling, and efficacy testing in patients for at least one medical indication, as required by the U.S. Biologics Price Competition and Innovation Act (BPCIA). The efficacy testing can be waived if the drug has known pharmacodynamic (PD) markers, leaving most therapeutic proteins out of this concession. To overcome this, the FDA suggests that biosimilar developers discover PD biomarkers using omics technologies such as proteomics, glycomics, transcriptomics, genomics, epigenomics, and metabolomics. This approach is redundant since the mode-action-action biomarkers of approved therapeutic proteins are already available, as compiled in this paper for the first time. Other potential biomarkers are receptor binding and pharmacokinetic profiling, which can be made more relevant to ensure biosimilarity without requiring biosimilar developers to conduct extensive research, for which they are rarely qualified.

Obesity-related cardiometabolic indicators modify the associations of personal noise exposure with heart rate variability: A further investigation on the Study among Obese and Normal-weight Adults (SONA)

Elucidating the associations between environmental noise and heart rate variability (HRV) would be beneficial for the prevention and control of detrimental cardiovascular changes. Obese people have been found to manifest heightened susceptibility to the adverse effects of noise on HRV. However, the underlying mechanisms remain unclear. Based on 53 normal-weight and 44 obese young adults aged 18-26 years in Beijing, China, this study aimed to investigate the role of obesity-related cardiometabolic indicators for associations between short-term environmental noise exposure and HRV in the real-world context. The participants underwent personal noise exposure and ambulatory electrocardiogram monitoring using portable devices at 5-min intervals for 24 continuous hours. Obesity-related blood pressure, glucose and lipid metabolism, and inflammatory indicators were subsequently examined. Generalized mixed-effect models were used to estimate the associations between noise exposure and HRV parameters. The C-peptide, homeostasis model assessment of insulin resistance (HOMA-IR), and leptin levels were higher in obese participants compared to normal-weight participants. We observed amplified associations between short-term noise exposure and decreases in HRV among participants with higher C-peptide, HOMA-IR, and leptin levels. For instance, a 1 dB(A) increment in 3 h-average noise exposure level preceding each measurement was associated with changes of -0.20% (95%CI: -0.45%, 0.04%) and -1.35% (95%CI: -1.85%, -0.86%) in standard deviation of all normal to normal intervals (SDNN) among participants with lower and higher C-peptide levels, respectively (P for interaction <0.05). Meanwhile, co-existing fine particulate matter (PM2.5) could amplify the associations between noise and HRV among obese participants and participants with higher C-peptide, HOMA-IR, and leptin levels. The more apparent associations of short-term exposure to environmental noise with HRV and the effect modification by PM2.5 may be partially explained by the higher C-peptide, HOMA-IR, and leptin levels of obese people.

Antenatal depression moderated the association between gestational diabetes mellitus and fetal hyperinsulinism

BACKGROUND

Gestational diabetes mellitus and antenatal depression are common comorbidities. However, the combined effects of antenatal depression and diabetes mellitus during pregnancy on fetal β-cell function are unknown.

OBJECTIVE

This study aimed to test whether the association of maternal gestational diabetes mellitus and glucose metabolism with cord blood C-peptide levels varies with antenatal depression.

STUDY DESIGN

Data on mother-child pairs (N=5734) from the Maternal and Infant Health Cohort Study in Hefei were analyzed. Gestational diabetes mellitus was diagnosed using the 75-g oral glucose tolerance test at 24 to 28 weeks of gestation. Antenatal depression was measured using the Edinburgh Postnatal Depression Scale during midpregnancy and late pregnancy. Cord blood samples were collected at delivery and tested for C-peptide levels.

RESULTS

A total of 1054 mothers (18.38%) were diagnosed with gestational diabetes mellitus. Gestational diabetes mellitus was associated with a 5.57 (95% confidence interval, 3.65-7.50) percentile higher cord blood C-peptide level. This association varied with depression severity: the differences in cord blood C-peptide percentile for gestational diabetes mellitus vs no gestational diabetes mellitus were 5.12 (95% confidence interval, 2.81-9.75) for nonantenatal depression, 7.36 (95% confidence interval, 2.85-13.38) for moderate antenatal depression, and 10.06 (95% confidence interval, 4.69-14.8) for severe antenatal depression in midpregnancy. Similar associations stratified by antenatal depression in late pregnancy were observed. Antenatal depression was significantly positively correlated with fetal hyperinsulinism in participants with gestational diabetes mellitus but not in participants without gestational diabetes mellitus.

CONCLUSION

Antenatal depression, which is related to maternal hyperglycemia, can aggravate the risk of fetal hyperinsulinism in early life.

Circulating hormones and risk of gastric cancer by subsite in three cohort studies

BACKGROUND

Obesity has been positively associated with gastric cancer. Excess fat impacts hormones, which have been implicated in carcinogenesis. We investigated obesity-related hormones and cardia gastric cancer (CGC) and non-cardia gastric cancer (NCGC) risk.

METHODS

Nested case-control studies were conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort (61 CGCs, and 172 NCGCs and matched controls) and the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) study (100 CGCs and 65 NCGCs and matched controls); serum hormones were measured. In UK-Biobank (n = 458,713), we included 137 CGCs and 92 NCGCs. Sex-specific analyses were conducted. For EPIC and ATBC, odds ratios (ORs), and for UK-Biobank hazard ratios (HRs), were estimated using conditional logistic regression and Cox regression, respectively.

RESULTS

Insulin-like growth-factor-1 was positively associated with CGC and NCGC in EPIC men (ORper 1-SD increase 1.94, 95% CI 1.03-3.63; ORper 1-SD increase 1.63, 95% CI 1.05-2.53, respectively), with similar findings for CGC in UK-Biobank women (HRper 1-SD increase 1.76, 95% CI 1.08-2.88). Leptin in EPIC men and C-peptide in EPIC women were positively associated with NCGC (ORT3 vs. T1 2.72, 95% CI 1.01-7.34 and ORper 1-SD increase 2.17, 95% CI 1.19-3.97, respectively). Sex hormone-binding globulin was positively associated with CGC in UK-Biobank men (HRper 1-SD increase 1.29, 95% CI 1.02-1.64). Conversely, ghrelin was inversely associated with NCGC among EPIC and ATBC men (ORper 1-SD increase 0.53, 95% CI 0.34-0.84; ORper 1-SD increase 0.22, 95% CI 0.10-0.50, respectively). In addition, dehydroepiandrosterone was inversely associated with CGC in EPIC and ATBC men combined.

CONCLUSIONS

Some obesity-related hormones influence CGC and NCGC risk.

Effects of C-Peptide on Dexamethasone-Induced In Vitro and In Vivo Models as a Potential Therapeutic Agent for Muscle Atrophy

This study aimed to investigate the effects of C-peptide on C2C12 myotubes and a mouse model. Both in vitro and in vivo experiments were conducted to elucidate the role of C-peptide in muscle atrophy. Various concentrations (0, 0.01, 0.1, 1, 10, and 100 nM) of C-peptide were used on the differentiated C2C12 myotubes with or without dexamethasone (DEX). C57BL/6J mice were administered with C-peptide and DEX for 8 days, followed by C-peptide treatment for 12 days. Compared to the DEX group, C-peptide increased the fusion and differentiation indices and suppressed atrophic factor expression in C2C12 myotubes. However, 100 nM C-peptide decreased the fusion and differentiation indices and increased atrophic factor expression regardless of DEX treatment. In C57BL/6J mice, DEX + C-peptide co-treatment significantly attenuated the body and muscle weight loss and improved the grip strength and cross-sectional area of the gastrocnemius (Gas) and quadriceps (Quad) muscles. C-peptide downregulated the mRNA and protein levels of muscle degradation-related markers, particularly Atrogin-1, in Gas and Quad muscles. This study underscores the potential of C-peptides in mitigating muscle weight reduction and preserving muscle function during muscle atrophy via molecular regulation. In addition, the work presents basic data for future studies on the effect of C-peptide on diabetic muscular dystrophy.

Clinical prediction models combining routine clinical measures identify participants with youth-onset diabetes who maintain insulin secretion in the range associated with type 2 diabetes: The SEARCH for Diabetes in Youth Study

Objective

With the high prevalence of pediatric obesity and overlapping features between diabetes subtypes, accurately classifying youth-onset diabetes can be challenging. We aimed to develop prediction models that, using characteristics available at diabetes diagnosis, can identify youth who will retain endogenous insulin secretion at levels consistent with type 2 diabetes (T2D).

Methods

We studied 2,966 youth with diabetes in the prospective SEARCH study (diagnosis age ≤19 years) to develop prediction models to identify participants with fasting c-peptide ≥250 pmol/L (≥0.75ng/ml) after >3 years (median 74 months) of diabetes duration. Models included clinical measures at baseline visit, at a mean diabetes duration of 11 months (age, BMI, sex, waist circumference, HDL-C), with and without islet autoantibodies (GADA, IA-2A) and a Type 1 Diabetes Genetic Risk Score (T1DGRS).

Results

Models using routine clinical measures with or without autoantibodies and T1DGRS were highly accurate in identifying participants with c-peptide ≥0.75 ng/ml (17% of participants; 2.3% and 53% of those with and without positive autoantibodies) (area under receiver operator curve [AUCROC] 0.95-0.98). In internal validation, optimism was very low, with excellent calibration (slope=0.995-0.999). Models retained high performance for predicting retained c-peptide in older youth with obesity (AUCROC 0.88-0.96), and in subgroups defined by self-reported race/ethnicity (AUCROC 0.88-0.97), autoantibody status (AUCROC 0.87-0.96), and clinically diagnosed diabetes types (AUCROC 0.81-0.92).

Conclusion

Prediction models combining routine clinical measures at diabetes diagnosis, with or without islet autoantibodies or T1DGRS, can accurately identify youth with diabetes who maintain endogenous insulin secretion in the range associated with type 2 diabetes.

Blood C-peptide concentration as a proxy marker of cardiovascular disease: An observational cross-sectional study

Background and Aims

Cardiovascular diseases (CVDs) are among the leading causes of disability and early death in sub-Saharan Africa. Most of the current blood tests for CVD diagnosis involve performing about three test profiles; often at additional cost to patients. C-peptide, a cleavage product of proinsulin, is a promising marker that has the potential to serve as a proxy marker for diagnosing CVDs in resource-poor settings.

Methodology

The study was an observational cross-sectional one and involved 127 consenting persons diagnosed with CVD and 127 individuals without CVD. The socio-demographic and clinical characteristics of participants were obtained. Blood levels of C-peptide, fasting plasma glucose (FPG), total creatinine kinase (CK), creatine kinase myocardial bound (CKMB), lactate dehydrogenase (LDH), propeptide of brain natriuretic peptide (PBNP), Troponin T, lipids, and biomarkers of kidney and liver function were analyzed using ELISA and an automated analyzer. Insulin resistance was computed using the modified homeostatic model assessment (HOMA-IR).

Results

The CVD Group had significantly higher levels of C-peptide, CK, CKMB, troponin T, PBNP, FPG, HOMA-IR, and several selected kidney, liver, and lipid parameters compared to the non-CVD Group (p < 0.05 for all). Troponin T recorded a positive correlation (r = 0.34, p < 0.001) with C-peptide among the CVD Group. The sensitivity and specificity of C-peptide in identifying CVD were 96.1% and 91.3% respectively (area under the curve = 0.938, p < 0.001).

Conclusion

C-peptide levels were higher in the CVD Group and appeared to be a valuable (high sensitivity and specificity) biomarker in detecting CVD.

HbA1c/C-peptide ratio is associated with angiographic thrombus burden and short-term mortality in patients presenting with ST-elevation myocardial infarction

OBJECTIVES

Angiographic high thrombus burden (HTB) is associated with increased adverse cardiovascular events in patients with ST-elevation myocardial infarction (STEMI). HbA1c and C-peptide are two interrelated bioactive markers that affect many cardiovascular pathways. HbA1c exhibits prothrombogenic properties, while C-peptide, in contrast, exhibits antithrombogenic effects. In this study, we aimed to demonstrate the value of combining these two biomarkers in a single fraction in predicting HTB and short-term mortality in patients with STEMI.

METHODS

1202 patients who underwent primary percutaneous coronary intervention (pPCI) for STEMI were retrospectively included in this study. The study population was divided into thrombus burden (TB) groups and compared in terms of basic clinical demographics, laboratory parameters and HbA1c/C-peptide ratios (HCR). In addition, short-term mortality of the study population was compared according to HCR and TB categories.

RESULTS

HCR values were significantly higher in the HTB group than in the LTB group (3.5 ± 1.2 vs. 2.0 ± 1.1; P  < 0.001; respectively). In the multivariable regression analysis, HCR was determined as an independent predictor of HTB both as a continuous variable [odds ratio (OR): 2.377; confidence interval (CI): 2.090-2.704; P  < 0.001] and as a categorical variable (OR: 5.492; CI: 4.115-7.331; P  < 0.001). In the receiver operating characteristic (ROC) analysis, HCR predicted HTB with 73% sensitivity and 72% specificity, and furthermore, HCR's predictive value for HTB was superior to HbA1c and C-peptide. The Kaplan-Meier cumulative survival curve showed that short-term mortality increased at HTB. In addition, HCR strongly predicted short-term mortality in Cox regression analysis.

CONCLUSIONS

In conclusion, HCR is closely associated with HTB and short-term mortality in STEMI patients.

The Level of Inflammatory Markers and Their Relationship with Fat Tissue Distribution in Children with Obesity and Type 2 Diabetes Mellitus

OBJECTIVE

This study aimed to determine the changes in proinflammatory and anti-inflam- matory markers in children aged 10-18, who were not diagnosed with type 2 diabetes mel- litus, were obese/overweight, and children with type 2 diabetes mellitus. In addition, we aimed to investigate whether these markers were associated with clinical and laboratory parame- ters, subcutaneous adipose tissue, preperitoneal adipose tissue, visceral adipose tissue, and hepatosteatosis.

MATERIALS AND METHODS

Children between the ages of 10 and 18, obese/overweight, with type 2 diabetes mellitus, and with a normal body mass index were included. Fat tissue thick- ness was measured. Tumor necrosis factor-α, interleukin-1β, interleukin-6, interleukin-18, and interferon-γ as proinflammatory markers and transforming growth factor-β and interleukin-10 levels as anti-inflammatory markers were studied.

RESULTS

Twenty-eight (31.8%) controls, 44 (50%) obese/overweight, and 16 (18.2%) patients with type 2 diabetes mellitus were included in our study. Age, sex, and puberty were similar between the groups. In the type 2 diabetes mellitus group, the subcutaneous fat tissue thick- ness was higher than that in the obese group, and the preperitoneal and visceral fat tissue thicknesses were similar to those in the obese group. Proinflammatory markers and interleu- kin-10 levels were similar in the obese/overweight, type 2 diabetes mellitus, and control groups. Transforming growth factor-β levels were significantly lower in the type 2 diabetes mellitus group than in the control group (P = .039). Transforming growth factor-β levels and other labo- ratory variables did not differ significantly in the type 2 diabetes mellitus group.

CONCLUSION

While there was no change in all markers in the obese/overweight group com- pared with the control group, proinflammatory markers in the type 2 diabetes mellitus group were similar to those in the obese/overweight and control groups, and transforming growth factor-β level, an anti-inflammatory marker, was lower in the type 2 diabetes mellitus group than in the control group.

Selected musculoskeletal disorders in patients with thyroid dysfunction, diabetes, and obesity

Many medical conditions affect the skeletal system and constitute independent risk factors for fractures. The action of thyroid hormones is necessary to maintain adequate development, mineralization, and bone strength. Untreated hyperthyroidism can lead to a decrease in bone mineral density (BMD), osteoporosis, and pathological fractures. In hypothyroidism, the changes in the quality of bone structure lead to an increase in the frequency of fractures. Excessive body weight negatively impacts fracture risk, increases the risk of osteoarthritis and accelerates the development of rheumatoid arthritis and osteoporosis. Type 1 and type 2 diabetes are associated with an increased risk of bone fractures despite different etiopathogenesis due to the duration of the disease and the pro-inflammatory state, the incorporation of advanced glycation end products (AGEs) into the bone matrix, and microvascular disorders. This study summarizes the current literature on the influence of thyroid dysfunction, obesity, and diabetes on the skeletal system.

Exploration of suitable external quality assessment materials for serum C-peptide measurement

OBJECTIVES

To find suitable external quality assessment (EQA) materials for serum C-peptide, we evaluated the commutability of five types of processed materials.

METHODS

Seventy-four individual serum samples and 12 processed samples including three EQA samples currently in use, frozen human serum pools (FHSP), and three other kinds of processed samples were prepared by dissolving WHO International Standard Reagent for C-peptide (WHO ISR 13/146) in three different matrixes: 0.05 % bovine serum albumin, fetal bovine serum and human serum pools. Samples were analyzed using the isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method and six widely used immunoassays. The commutabilities of processed materials were assessed according to the difference in bias approach recommended by the IFCC. And the short- and long-term stability of FHSP samples at different temperatures were also evaluated.

RESULTS

Out of the five kinds of processed materials, FHSP samples were commutable on most assays. In contrast, the EQA materials currently in use were only commutable on a few immunoassays. Additionally, processed materials derived from WHO ISR 13/146 were found to be un-commutable on over half of immunoassays. The FHSP samples could be stably stored at 4 and -20 °C for at least 16 days, and at -80 °C for at least 1 year, but at room temperature only for 12 h.

CONCLUSIONS

With clarified commutability and stability information, the human serum pool samples along with the developed ID-LC-MS/MS method could be used in the EQA program to promote the comparability among laboratories for C-peptide measurement in China.

Association of common variants of TCF7L2 and PCSK2 with gestational diabetes mellitus in West Bengal, India

The genetic etiology of gestational diabetes mellitus (GDM) was suggested to overlap with type-2 diabetes(T2D). Transcription factor 7-like 2 (TCF7L2) and Proprotein Convertase Subtilisin/Kexin type 2 (PCSK2) are T2D susceptibility genes of the insulin synthesis/processing pathway. We analyzed associations of TCF7L2 and PCSK2 variants with GDM risk and evaluated their potential impact on impaired insulin processing in an eastern Indian population. The study included 114 GDM (case) and 228 non-GDM pregnant women (control). rs7903146, rs4132670, rs12255372 of TCF7L2, and rs2269023 of PCSK2 were genotyped by PCR-RFLP, and genotype distributions were compared between case and control. Fasting serum proinsulin and C-peptide levels were measured by ELISA and the Proinsulin/C-peptide ratio was considered an indicator of proinsulin conversion. Significantly higher frequency of risk allele (T) of rs12255372 (p = 0.02, OR = 2.0, 95%CI = 1.11-3.64) and rs4132670 (p = 0.002, OR = 2.26, 95%CI = 1.32-3.87) of TCF7L2 was found in GDM cases than non-GDM controls; TT genotype was associated with significantly increased disease risk. In rs7903146 (TCF7L2) and rs2269023 (PCSK2), although the frequency of risk allele (T) was not significantly higher in cases than controls, an association of TT for both variants remained significant with higher GDM risk in the recessive model. Increased serum pro-insulin and proinsulin:c-peptide ratio was found in GDM than non-GDM women and the phenomenon showed significant association with careers of risk alleles for TCF7L2 variants. In conclusion, TCF7L2 and PCSK2 variants are related to GDM risk in the studied population and hence may serve as potential biomarkers for assessing the disease risk. TCF7L2 variants contribute to impaired insulin processing.

Predictors of Responsiveness to GLP-1 Receptor Agonists in Insulin-Treated Patients with Type 2 Diabetes

Background

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are potent antihyperglycemic agents with beneficial effects on weight, cardiovascular, and renal outcomes. Physicians lack guidance as to which patients with insulin-requiring type 2 diabetes will respond best to GLP-1 RAs with respect to glycemic control, insulin dose reduction, and weight loss. This study evaluated the efficacy of GLP-1 RAs in patients with type 2 diabetes on insulin and patient factors that may predict a beneficial clinical response.

Methods

Adults with type 2 diabetes treated with insulin who had a GLP-1 RA added to their regimen were evaluated retrospectively. Baseline parameters and outcomes at 3, 6, and 12 months were collected.

Results

Among the 81 patients included, there was a mean reduction in hemoglobin A1C of 0.94% (SD, 0.26; p = 0.0007), 0.40% (SD, 0.21; p = 0.0636), and 0.58% (SD, 0.23, p = 0.0154) at 3, 6, and 12 months, respectively, following the addition of a GLP-1 RA. There was also a reduction in body weight noted at each time point. Baseline characteristics including BMI, duration of diabetes, and insulin requirement did not significantly affect A1C reduction when GLP-1 RA was added. At 3 months, patients with a random C-peptide that was normal (≥0.8 ng/ml) were significantly more likely to have discontinued insulin than those with random C-peptide that was low (<0.8 ng/ml) (11 of 23 vs. 0 of 7 patients, p = 0.029).

Conclusions

The addition of a GLP-1 RA reduced HbA1C, weight, and insulin requirements in this cohort of patients with type 2 diabetes on insulin. BMI, baseline insulin dose, and diabetes duration did not predict response. A C-peptide level ≥ 0.8 ng/ml predicted a beneficial response after 3 months of therapy.

Insulin: Know what your immunoassay detects. Evaluation of two new immunoassays

BACKGROUND

Insulin is essential for glycemic regulation but diseases can cause a default or an excess of insulin secretion leading to dysregulated glycemia. Hence, measurement of insulinemia is useful to investigate hypoglycemia, determine the pathogenesis of diabetes and evaluate β-cell function. Thus, diabetic patients need supplementation with recombinant human insulin and/or insulin analogues. Analogues have primary sequences different from native human insulin and may not be detected by some immunoassays. The objective of our study was to evaluate new insulin immunoassays by determining their ability to detect different types of human insulin or analogues.

METHODS

This study compared the reactivity of two new insulin immunoassays with five well-established immunoassays on ten commercial insulins. We also measured insulin in blood samples from diabetic or pancreas transplant patients with known treatment.

RESULTS

Contrary to recombinant human insulin, there were differences in the specificity to insulin analogues. We distinguished three immunoassay categories: those recognizing all types of insulin such as the non-specific BI-INS-IRMA®, Architect® and Access® immunoassays; those recognizing human insulin only (Cobas®); and those recognizing human insulin and analogues in variable proportions (Liaison XL®, iFlash® and Maglumi®).

CONCLUSION

An accurate biological interpretation of insulinemia relies on knowledge of the specificity of the immunoassay used.

Copper(II) Affects the Biochemical Behavior of Proinsulin C-peptide by Forming Ternary Complexes with Serum Albumin

Peptide hormones are essential signaling molecules with therapeutic importance. Identifying regulatory factors that drive their activity gives important insight into their mode of action and clinical development. In this work, we demonstrate the combined impact of Cu(II) and the serum protein albumin on the activity of C-peptide, a 31-mer peptide derived from the same prohormone as insulin. C-peptide exhibits beneficial effects, particularly in diabetic patients, but its clinical use has been hampered by a lack of mechanistic understanding. We show that Cu(II) mediates the formation of ternary complexes between albumin and C-peptide and that the resulting species depend on the order of addition. These ternary complexes notably alter peptide activity, showing differences from the peptide or Cu(II)/peptide complexes alone in redox protection as well as in cellular internalization of the peptide. In standard clinical immunoassays for measuring C-peptide levels, the complexes inflate the quantitation of the peptide, suggesting that such adducts may affect biomarker quantitation. Altogether, our work points to the potential relevance of Cu(II)-linked C-peptide/albumin complexes in the peptide's mechanism of action and application as a biomarker.

A Cross-sectional Study to Assess Beta-Cell Function in Individuals with Recently Diagnosed Young-Onset Type 2 Diabetes Mellitus and Its' Complications

Objective

The primary objective was to assess beta-cell function of recently-diagnosed young-onset type 2 diabetes mellitus (T2DM) individuals using basal and stimulated C-peptide levels. The secondary objective was to examine the association between C-peptide with metabolic factors and diabetes complications.

Methodology

A cross-sectional study was conducted for young-onset T2DM individuals aged 18-35 years with a disease duration of not more than 5 years. Plasma C-peptide was measured before and after intravenous glucagon injection. Demographic data, medical history and complications were obtained from medical records and clinical assessment. Continuous data were expressed as median and interquartile range (IQR). Categorical variables were described as frequency or percentage. Multivariable linear regression analysis was used to determine factors associated with C-peptide levels.

Results

113 participants with young-onset T2DM with a median (IQR) age of 29.0 (9.5) years and 24 (36) months were included in this study. The median (IQR) basal and stimulated C-peptide was 619 (655) pmol/L and 1231 (1024) pmol/L. Adequate beta-cell function was present in 78-86% of the participants based on the basal and stimulated C-peptide levels. We found hypertension, obesity and diabetic kidney disease (DKD) to be independently associated with higher C-peptide levels. In contrast, females, smokers, those on insulin therapy and with longer duration of disease had lower C-peptide levels.

Conclusion

Most recently diagnosed young-onset T2DM have adequate beta-cell function. Elevated C-peptide levels associated with obesity, hypertension and diabetic kidney disease suggest insulin resistance as the key driving factor for complications.

COMPARISON OF C-PEPTIDE LEVELS IN MONOGENIC FORMS OF DIABETES WITH OTHER TYPES OF DIABETES: A SINGLE-CENTER STUDY

Objective

This study aimed to evaluate the utility of C-peptide levels in the differentiation of monogenic forms of diabetes from type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) in clinical practice.

Subjects and Methods

A total of 104 patients aged >16 who visited the Dicle University's Faculty of Medicine between April 2011 and December 2020 and were diagnosed with monogenic diabetes by genetic analysis or with T1DM and T2DM were randomly selected for retrospective evaluation. The C-peptide levels of these patients at the time of diagnosis of diabetes were compared.

Results

Of the 104 patients, 24 (23%) were diagnosed with maturity-onset diabetes of the young (MODY), 40 (38.5%) with T1DM, and 40 (38.5%) with T2DM. Median C-peptide levels (ng/mL) (interquartile range) were 1.78 (1.24-2.88) in MODY group, 0.86 (0.34-1.22) in T1DM group, and 2.38 (1.58-4.27) in T2DM group.

Conclusions

There was a difference in C-peptide levels between MODY and T1DM groups but not between MODY and T2DM groups. As per clinical evaluations, although C-peptide levels of patients with MODY are similar to those of patients with T2DM patients, the possibility of C-peptide levels being similar to those required for T1DM diagnosis should also be considered.

An Accurate Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry Method for Serum C-Peptide and Its Use in Harmonization in China

Background

Serum C-peptide results from various routine methods used in China are highly variable, warranting well-performing methods to serve as an accuracy base to improve the harmonization of C-peptide measurements in China. We developed an accurate isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for serum C-peptide measurement and explored its use in harmonization.

Methods

After protein precipitation with Z_nSO₄ solution, C-peptide was extracted from serum samples by anion-exchange solid-phase extraction and quantified by ID-LC-MS/MS in positive ion mode. The precision and analytical recovery of the ID-LC-MS/MS method were assessed. Seventy-six serum samples were analyzed using the ID-LC-MS/MS method and six routine immunoassays. Ordinary linear regression (OLR) and Bland-Altman (BA) analyses were conducted to evaluate the relationship between the ID-LC-MS/MS method and routine immunoassays. Five serum pool samples assigned using the ID-LC-MS/MS method were used to recalibrate the routine assays. OLR and BA analyses were re-conducted after recalibration.

Results

The within-run, between-run, and total precision for the ID-LC-MS/MS method at four concentrations were 1.0%-2.1%, 0.6%-1.2%, and 1.3%-2.2%, respectively. The analytical recoveries for the ID-LC-MS/MS method at three concentrations were 100.3%-100.7%, 100.4%-101.0%, and 99.6%-100.7%. The developed method and the immunoassays were strongly correlated, with all R² >0.98. The comparability among the immunoassays was substantially improved after recalibration.

Conclusions

The performance of the ID-LC-MS/MS method was carefully validated, and this method can be used to improve the harmonization of serum C-peptide measurements in China.

Effect of glucagon-like peptide-1 receptor agonist on insulin secretion index and serum Wnt5a protein in patients with new-onset type 2 diabetes mellitus

Objective

Previous studies have found that wnt5a promotes β-cell insulin secretion and reduced concentrations in patients with type 2 diabetes. GLP-1RA (Glucagon-like peptide-1 receptor agonists) can regulate insulin secretion. However, the evidence that GLP-1RA affect insulin secretion through the Wnt5a is inconclusive. Therefore, this study aimed to evaluate the effect of GLP-1 RA on wnt5a levels in patients with type 2 diabetes.

Methods

A total of 56 onset diabetics were selected our study, 29 of them were treated by GLP-1RAs (1.2mg subcutaneous injection once a day, liraglutide, Novo Nordisk), the rest (27 case) treated by Metformin (0.5 g twice a day, Glucophage, Merck). Individuals who were using medications to manage platelet (Aspirin) and cholesterol (Statins) were enrolled and continued treatment throughout the study.

Results

Our study found that the waist circumference and insulin secretion index in the GLP-1RA intervention group were significantly increased, and the insulin resistance index was lower than that of the control group. More interestingly, the serum Wnt5a protein level increased dramatically after the GLP-1RA intervention, and the level of Secreted frizzled-related protein 5 (Sfrp5) decreased compared with the control group. Multivariate linear regression analysis showed that the change of HOMA-β (Homeostasis model assessment- β) was significantly correlated with the changes of Wnt5a and Sfrp5, and the change of Wnt5a protein was positively correlated with HOMA-β.

Conclusion

Our results confirmed that GLP-1RA may improve HOMA-β in patients with type 2 diabetes by affecting the level of Wnt5a protein.

Changes in C-Peptide Values in Children with Type 1 Diabetes - a Three-Year Study

Background: C-peptide is used as an important indicator of residual insulin secretion in patients diagnosed with type 1 diabetes mellitus (T1DM) and treated with insulin. Aim:We have aimed to monitor the serum C-peptide (CP) levels during the first three years after diagnosis of T1DM in a cohort of children admitted to the Diabetes Department of "M. S. Curie" Emergency Clinical Hospital for Children, Bucharest, Romania, and to investigate the factors that could influence the rate of decline in its secretion. Method:We conducted a longitudinal, retrospective cohort study on a group of 215 children and adolescents who met the inclusion criteria and were monitored in our clinic over the course of a long period of time. We analyzed several parameters, including fasting serum CP values at diagnosis and yearly throughout T1DM evolution, the severity of diabetic ketoacidosis (DKA) at onset, HbA1c at diagnosis, family history of T1DM/T2DM, patient gender and presence of concurrent acute infectious disease at diagnosis, with the purpose of evaluating their influence on the preservation of endogenous insulin secretion. Based on serum CP value measured three years after T1DM onset, patients were divided into two groups: group 1, with low insulin residual secretion (CP < 0.6 ng/mL), and group 2, with preserved insulin residual secretion (CP ≥0.6 ng/mL) Results:At the moment of diagnosis, patients in group 1 were younger than those in group 2 (6.03 ± 3.54 years and 9.76 ± 2.75 years, respectively). The proportion of children with diabetic ketoacidosis (DKA) at onset was greater in group 1 (68% of patients) than group 2, in which the majority of subjects (60%) did not have DKA. The C-peptide value at diagnosis was significantly lower (0.55 ± 0.36 ng/mL) among patients in group 1 than those in group 2 (1.11 ± 0.59 ng/mL). In group 1 there was a higher proportion of patients (65%) with acute infectious disease at onset. Family history of T1DM/T2DM was associated with a more rapid decline in CP values. Our data showed no correlation between CP levels monitored for three years and HbA1c at diagnosis and no association with the gender of each patient. Conclusion:Patients with higher CP concentrations at diagnosis maintained increased values (> 0.6 ng/mL) three years after disease onset. Younger children had a faster decline of CP secretion during the first three years following diabetes diagnosis. In patients with severe symptoms (DKA) and associated infectious disease at onset, a risk of rapid CP decline was found.