Which C-peptide assay do you use? Increasing need for describing C-peptide assay performance

Dekker, Pim; Vries, Martine de; Aanstoot, Henk‐Jan; Groen, J

doi:10.5114/pedm.2022.113741

Cited by 3 publications

(3 citation statements)

References 4 publications

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“…Many different commercially available C-peptide assays are used for research and routine analysis, but not all assays are suitable for measurements in the lower picomolar range and those which are not equally sensitive. 45 Samples from the cohort (only from one centre) were first used to compare and verify the ultrasensitive Mercodia enzyme-linked immunosorbent C-peptide assay (ELISA) with the Beckman immunoradiometric assay (IRMA) for C-peptide. Reproducibility (coefficient of variation), limit of blank, limit of detection and limit of quantitation were compared.…”

Section: Findings To Datementioning

confidence: 99%

Cohort profile: the ‘Biomarkers of heterogeneity in type 1 diabetes’ study—a national prospective cohort study of clinical and metabolic phenotyping of individuals with long-standing type 1 diabetes in the Netherlands

Aanstoot,

Varkevisser,

Mul

et al. 2024

BMJ Open

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PurposeThe ‘Biomarkers of heterogeneity in type 1 diabetes’ study cohort was set up to identify genetic, physiological and psychosocial factors explaining the observed heterogeneity in disease progression and the development of complications in people with long-standing type 1 diabetes (T1D).ParticipantsData and samples were collected in two subsets. A prospective cohort of 611 participants aged ≥16 years with ≥5 years T1D duration from four Dutch Diabetes clinics between 2016 and 2021 (median age 32 years; median diabetes duration 12 years; 59% female; mean glycated haemoglobin (HbA1c) 61 mmol/mol (7.7%); 61% on insulin pump; 23% on continuous glucose monitoring (CGM)). Physical assessments were performed, blood and urine samples were collected, and participants completed questionnaires. A subgroup of participants underwent mixed-meal tolerance tests (MMTTs) at baseline (n=169) and at 1-year follow-up (n=104). Genetic data and linkage to medical and administrative records were also available. A second cross-sectional cohort included participants with ≥35 years of T1D duration (currently n=160; median age 64 years; median diabetes duration 45 years; 45% female; mean HbA1c 58 mmol/mol (7.4%); 51% on insulin pump; 83% on CGM), recruited from five centres and measurements, samples and 5-year retrospective data were collected.Findings to dateStimulated residual C-peptide was detectable in an additional 10% of individuals compared with fasting residual C-peptide secretion. MMTT measurements at 90 min and 120 min showed good concordance with the MMTT total area under the curve. An overall decrease of C-peptide at 1-year follow-up was observed. Fasting residual C-peptide secretion is associated with a decreased risk of impaired awareness of hypoglycaemia.Future plansResearch groups are invited to consider the use of these data and the sample collection. Future work will include additional hormones, beta-cell-directed autoimmunity, specific immune markers, microRNAs, metabolomics and gene expression data, combined with glucometrics, anthropometric and clinical data, and additional markers of residual beta-cell function.Trial registration numberNCT04977635.

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Section: Findings To Datementioning

confidence: 99%

Cohort profile: the ‘Biomarkers of heterogeneity in type 1 diabetes’ study—a national prospective cohort study of clinical and metabolic phenotyping of individuals with long-standing type 1 diabetes in the Netherlands

Aanstoot,

Varkevisser,

Mul

et al. 2024

BMJ Open

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“…Many C-peptide assays are commercially available for research and routine use. 35 We compared the ultrasensitive Mercodia enzyme-linked immunosorbent C-peptide assay (ELISA) with the Beckman immunoradiometric assay (IRMA) for C-peptide, assessing reproducibility (coefficient of variation [CV]), limit of blank (LoB), limit of detection (LoD) and limit of quantitation (LoQ). 20 Because only the IRMA met the specifications claimed by the manufacturer, providing the lowest threshold for quantification of serum C-peptide, we chose this assay for our C-peptide analyses.…”

Section: C-peptide Assay Validation and Sample Analysismentioning

confidence: 99%

Cohort profile: the ‘Biomarkers of heterogeneity in type 1 diabetes’ study – a prospective cohort study of clinical and metabolic phenotyping of individuals with long-standing type 1 diabetes

Mul,

Varkevisser,

Aanstoot

et al. 2023

Preprint

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PurposeThe ‘Biomarkers of heterogeneity in type 1 diabetes’ study cohort was set up to identify genetic, physiological and psychosocial factors explaining the observed heterogeneity in disease progression and the development of complications in people with long-standing type 1 diabetes (T1D). Data and samples are available for new studies and collaborations.ParticipantsData- and samples were collected in two subsets. 1) A prospective cohort of 611 participants aged ≥16 years with ≥5 years T1D duration was recruited from four Dutch Diabetes clinics between June 2016 and March 2021. At baseline and 1- and 2-year follow-up visits, physical assessments were performed, and blood and urine samples were collected. Participants completed questionnaires about diabetes-related problems, quality of life, neuropathy and impaired awareness of hypoglycaemia at baseline and at the last follow-up visit. A subgroup of participants underwent mixed-meal tolerance tests (MMTT) at baseline (n=169) and at 1-year follow-up (n=104). Genetic data and linkage to medical and administrative records were also available. 2) A second cross-sectional cohort, aiming to include 200 participants aged ≥18 years with ≥35 years T1D duration, was recruited from 7 centres, collecting measurements and samples plus 5-year retrospective data.Findings to dateFasting residual C-peptide secretion associated with decreased risk of impaired awareness of hypoglycaemia. Stimulated residual C-peptide was detectable in an additional 10% of individuals compared with fasting residual C-peptide secretion. MMTT measurements at 90 minutes and 120 minutes showed good concordance with the MMTT total area under the curve. An overall decrease of C-peptide at 1-year follow-up was observed.Future plansResearch groups are invited to consider the use of this data and sample collection. Future work will include additional hormones, beta-cell-directed autoimmunity, specific immune markers, microRNA’s, metabolomics and gene expression data, combined with glucometrics, anthropometric/clinical data and additional markers of residual beta-cell function.Strengths and limitations of this studyStrengths- The Biomarker cohort is a large longitudinal prospective cohort study with three time points, collecting biosamples and clinical data from participants with well-established and long-standing type 1 diabetes (≥5 years).- A subgroup with detailed clinical data underwent MMTT tests at two timepoints allowing further residual beta-cell marker studies.- The Biomarker and Long-Term type 1 Diabetes cohorts represent a “real-world” population, also including participants from non-academic/-specialised centres.Limitations- Despite the fact that data and biosamples were collected from more than 600 participants, this number may be too low for (sub) stratification of the data (e.g. insulin delivery modality, different treating centres and therapies etc.).- In the prospective group there was a relatively high dropout rate of 25% after 2 years, largely affected by the Covid-19 outbreak.

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“…Cela pose, bien entendu, un problème, en particulier dans les travaux de recherche concernant le DT1, lorsque les résultats doivent être confrontés entre les études. 9 Il existe également des aspects précis quant à la façon de prélever le plasma pour doser le peptide-C de manière à conserver sa stabilité, mais ces considérations dépassent le cadre de cet article. 10 Dans l'étude DCCT, la limite maximale de peptide-C plasmatique pour être inclus dans le protocole (au début des années 80) était de 500 pmol/l après stimulation.…”

Section: Introductionunclassified

Sécrétion résiduelle en insuline et traitement du diabète de type 1. Intérêt des nouveaux dosages du peptide-C

Coune¹,

Paquot²

2022

Revue Médicale Suisse

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Intérêt des nouveaux dosages du peptide-CLe peptide-C plasmatique constitue une mesure directe de la sécrétion endogène d'insuline. Le développement de nouveaux dosages du peptide-C a permis de démontrer qu'il persiste chez 30 à 80 % des sujets diabétiques de type 1 (DT1) une faible sécrétion d'insuline, même sur le long terme. Plusieurs études ont établi que la persistance de la fonction B des îlots de Langerhans était associée à une protection contre le développement des complications microvasculaires et engendrait une réduction significative de la prévalence des hypoglycémies sévères chez les personnes DT1. Mais des études complémentaires sont encore nécessaires afin de préciser les mécanismes physiopathologiques sous-jacents et les stratégies thérapeutiques qui permettraient de maintenir la fonction de la cellule B et d'améliorer ainsi la qualité de vie des sujets avec un DT1. Residual insulin secretion and management of type 1 diabetes: Interest of new C-peptide assaysPlasma C-peptide represents a direct measure of endogenous insulin secretion. The development of new assays for measuring C-peptide have made it possible to demonstrate that a low insulin secretion persists in 30 to 80% of subjects with type 1 diabetes (T1D), even among those with long-standing disease. Several studies have established that the persistence of B cell function of the islets of Langerhans is associated with a protection against the development of microvascular complications and resulted in a significant reduction in the prevalence of severe hypoglycaemia in people with T1D. Further studies are needed to clarify the underlying pathophysiological mechanisms and the therapeutic strategies that would maintain B-cell function and thus improve the quality of life of patients with T1D.

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Which C-peptide assay do you use? Increasing need for describing C-peptide assay performance

Cited by 3 publications

References 4 publications

Cohort profile: the ‘Biomarkers of heterogeneity in type 1 diabetes’ study—a national prospective cohort study of clinical and metabolic phenotyping of individuals with long-standing type 1 diabetes in the Netherlands

Cohort profile: the ‘Biomarkers of heterogeneity in type 1 diabetes’ study—a national prospective cohort study of clinical and metabolic phenotyping of individuals with long-standing type 1 diabetes in the Netherlands

Cohort profile: the ‘Biomarkers of heterogeneity in type 1 diabetes’ study – a prospective cohort study of clinical and metabolic phenotyping of individuals with long-standing type 1 diabetes

Sécrétion résiduelle en insuline et traitement du diabète de type 1. Intérêt des nouveaux dosages du peptide-C

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