β-Cell Mass and Function, Pancreatic Volume, and Fat Differences Between Short- and Long-Duration Type 1 Diabetes: A Detailed PET/CT Imaging Study

People with recent-onset diabetes often have preserved C-peptide production, which tends to decline during the first 7 y after diagnosis and stabilizes thereafter. Whether this holds true for β-cell mass is unknown. In this pooled post hoc analysis, we aimed to investigate total β-cell mass in individuals with short- and long-duration type 1 diabetes. Methods: Data of 16 individuals with short- (<7 y) and 10 with long-duration type 1 diabetes (≥7 y) who underwent [68Ga]Ga-NODAGA-exendin-4 PET/CT and mixed-meal tolerance test were used to determine total β-cell mass and function, respectively. Intrapancreatic fat deposition and pancreatic volume were derived from CT. Results: Total β-cell mass was higher in individuals with short-duration type 1 diabetes compared with those with long-duration type 1 diabetes (4.4 ± 1.8 vs. 2.8 ± 1.3 kBq/MBq, P = 0.012). Larger pancreatic volume, lower intrapancreatic fat deposition, and higher β-cell function were observed in individuals with short-duration type 1 diabetes compared with the long-duration group. Total β-cell mass positively correlated with β-cell function (r = 0.46, P = 0.019) and pancreatic volume (r = 0.91, P < 0.0001) and inversely correlated with body mass index (r = −0.61, P = 0.0009). Conclusion: This study offers insights in the potential of imaging markers together with function tests to monitor disease progression and may offer valuable information for the timing to restore β-cell function or to slow down β-cell destruction.