Department of Endocrinology, The First Affiliated Hospital with Nanjing Medical University, Nanjing Medical University, Nanjing, Jiangsu, China.
Department of Endocrinology, The Affiliated Changzhou Second People's Hospital of Nanjing Medical University, Nanjing Medical University, Changzhou, Jiangsu, China.
Front Endocrinol (Lausanne). 2024 Aug 1;15:1419329. doi: 10.3389/fendo.2024.1419329. eCollection 2024.
The functional changes in alpha cells in patients with type 1 diabetes (T1D) with different residual beta cell functions remain poorly elucidated. The study aimed to investigate the relationship between glucagon secretion and C-peptide levels and to explore the relationship between glucagon response and glucose increment in respond to a secretagogue in a steamed bread meal tolerance test (BMTT) in T1D.
The study enrolled 43 adult patients with T1D and 24 healthy control subjects. Patients with T1D who underwent BMTT were divided into two groups based on peak C-peptide levels: C peptide low (CPL; C-peptide < 200 pmol/L; n=14) and high (CPH; C peptide ≥ 200 pmol/L; n=29). Plasma glucose, C-peptide, glucagon levels at 0, 30, 60, 120, and 180 min were measured. The glucagon response to the BMTT was defined by areas under the curve (AUC) as early (AUC), late (AUC), or total (AUC) glucagon.
Compared to healthy individuals, fasting plasma glucagon was lower and postprandial plasma glucagon level was increased in patients with T1D. Glucagon levels after BMTT between the CPL and CPH group showed significant group by time interaction. Peak glucagon and glucagon at 60-180 min, total and late glucagon response were higher in CPL than CPH group, while fasting glucagon and early glucagon response adjusted for glucose were comparable between CPL and CPH group. The higher late glucagon response and late glucagon response adjusted for glucose were associated with lower peak C-peptide in T1D. The higher late glucagon response and lower peak C-peptide were associated with the higher value of ▵glucose at 180 min.
Stimulated C-peptide levels affect the paradoxical increase in postprandial glucagon secretion in patients with T1D, especially late glucagon response. The exaggerated postprandial glucagon secretion further stimulates the elevation of postprandial glucose in patients with T1D.
1 型糖尿病（T1D）患者的α细胞功能变化与不同的β细胞功能残留之间的关系仍不清楚。本研究旨在探讨馒头餐耐量试验（BMTT）中胰高血糖素分泌与 C 肽水平的关系，并探讨胰高血糖素反应与葡萄糖增量之间的关系。
本研究纳入 43 例成年 T1D 患者和 24 例健康对照者。接受 BMTT 的 T1D 患者根据峰值 C 肽水平分为两组：C 肽低（CPL；C 肽 < 200pmol/L；n=14）和 C 肽高（CPH；C 肽≥200pmol/L；n=29）。测量 0、30、60、120 和 180 分钟时的血糖、C 肽和胰高血糖素水平。BMTT 的胰高血糖素反应通过曲线下面积（AUC）定义为早期（AUC）、晚期（AUC）或总（AUC）胰高血糖素。
与健康个体相比，T1D 患者空腹胰高血糖素降低，餐后胰高血糖素水平升高。CPL 和 CPH 组之间 BMTT 后的胰高血糖素水平显示出显著的组间时间交互作用。CPL 组的峰值胰高血糖素和 60-180 分钟时的胰高血糖素以及总胰高血糖素和晚期胰高血糖素反应均高于 CPH 组，而 CPL 和 CPH 组的空腹胰高血糖素和经葡萄糖校正的早期胰高血糖素反应无差异。更高的晚期胰高血糖素反应和经葡萄糖校正的晚期胰高血糖素反应与 T1D 患者的峰值 C 肽较低相关。更高的晚期胰高血糖素反应和更低的峰值 C 肽与 180 分钟时的 ▵葡萄糖值较高相关。
刺激的 C 肽水平影响 T1D 患者餐后胰高血糖素分泌的反常增加，尤其是晚期胰高血糖素反应。餐后胰高血糖素分泌的过度增加进一步刺激了 T1D 患者餐后血糖的升高。
