Residual insulin secretion in long‐standing type 1 diabetes

Diabetic Medicine, vol. 42, pp. e70104

Abstract

AIMS: Studies involving the use of sensitive C-peptide assays have revealed that a significant number of persons with long-standing type 1 diabetes have measurable serum C-peptide concentrations. We investigated meal-stimulated C-peptide levels in persons with diabetes duration of more than 30 years and whether they were associated with the presence of diabetes-associated autoantibodies. METHODS: This was an observational study of 105 participants with a clinical diagnosis of type 1 diabetes and a diabetes duration ≥30 years. Participants underwent mixed-meal tolerance tests (MMTTs) with measurements of C-peptide at 0 and 90 min. The levels of autoantibodies against GAD, IA-2 and ZnT8 were measured with radio-binding assays. RESULTS: Participants were divided into tertiles of post-meal (90 min) C-peptide values as non-responders (NR), low-responders (LR) and high-responders (HR). Compared with the NRs and HRs, the LRs had significantly lower BMI values (p < 0.001), plasma triglyceride concentrations (p = 0.010) and triglyceride/HDL-cholesterol ratios (p = 0.004). Twenty-nine and eight participants were positive for one or 2-3 antibodies, respectively. The presence of antibodies was not associated with post-meal C-peptide levels, as evidenced by the fact that the proportions of antibody-positive participants did not differ between the groups. CONCLUSIONS: We conclude that a subgroup of type 1 diabetes participants with long-standing diabetes (>30 years) has residual beta-cell function. Participants with type 1 diabetes and low stimulated C-peptide concentrations are characterized by lower BMI, triglyceride concentrations and higher insulin sensitivity.

Authors 7

1. Petra Augstein corresponding

   Institute for Diabetes Gerhardt Katsch

   Affiliation as printed

   Department for Diabetes and Metabolism Heart and Diabetes Center Karlsburg Karlsburg Germany

   Department for Diabetes and Metabolism, Heart and Diabetes Center Karlsburg, Karlsburg, Germany

2. Natalie Buschmann

   St. Josefs-Hospital Cloppenburg

   Affiliation as printed

   Department of General Surgery and Visceral Surgery St. Josefs‐Hospital Cloppenburg Cloppenburg Germany

   Department of General Surgery and Visceral Surgery, St. Josefs-Hospital Cloppenburg, Cloppenburg, Germany

3. Janik Riese Aachen Institute of Pathology

   RWTH Aachen University · Universitätsklinikum Aachen · Universitätsmedizin Greifswald · Universität Greifswald

   Affiliation as printed

   Experimental Surgical Research Laboratory, Department of General Surgery, Visceral, Thoracic and Vascular Surgery University Greifswald Greifswald Germany

   Institute of Pathology, RWTH University Hospital Aachen Aachen Germany

   Experimental Surgical Research Laboratory, Department of General Surgery, Visceral, Thoracic and Vascular Surgery, University Greifswald, Greifswald, Germany

   Institute of Pathology, RWTH University Hospital Aachen, Aachen, Germany

4. Sabine Bochnig

   Institute for Diabetes Gerhardt Katsch

   Affiliation as printed

   Department for Diabetes and Metabolism Heart and Diabetes Center Karlsburg Karlsburg Germany

   Department for Diabetes and Metabolism, Heart and Diabetes Center Karlsburg, Karlsburg, Germany

5. Peter Heinke

   Institute for Diabetes Gerhardt Katsch

   Affiliation as printed

   Institute of Diabetes “Gerhardt Katsch” Karlsburg Germany

   Institute of Diabetes "Gerhardt Katsch", Karlsburg, Germany

6. Michael Schlosser

   Universitätsmedizin Greifswald · Universität Greifswald

   Affiliation as printed

   Experimental Surgical Research Laboratory, Department of General Surgery, Visceral, Thoracic and Vascular Surgery University Greifswald Greifswald Germany

   Dr. Michael Schlosser, who played a decisive role in the planning and implementation of the study, died on 10 November 2022. Michael will be fondly remembered and sadly missed

   Experimental Surgical Research Laboratory, Department of General Surgery, Visceral, Thoracic and Vascular Surgery, University Greifswald, Greifswald, Germany

7. W. Kerner

   Institute for Diabetes Gerhardt Katsch

   Affiliation as printed

   Department for Diabetes and Metabolism Heart and Diabetes Center Karlsburg Karlsburg Germany

   Department for Diabetes and Metabolism, Heart and Diabetes Center Karlsburg, Karlsburg, Germany