Consistency of plasma glucagon levels in patients with type 1 diabetes after a 1-year period

Newly discovered knowledge pertaining to glucagon and its clinical applications

Glucagon has been defined as an 'insulin counteracting hormone', which raises blood glucose levels. Recent progress in basic research has shown that glucagon is closely involved in glucose and amino acid metabolism. Additionally, its secretion is intricately, but precisely, regulated by various mechanisms involving molecules in addition to glucose, thus showing its critical role in systemic nutrient metabolism. An innovative dual-antibody-linked immunosorbent assay for glucagon that improves measurement accuracy has been developed, and substantial clinical findings have been obtained using this new system. This discovery expanded the pathophysiological significance of glucagon and accelerated the development of its clinical applications in diabetes.

Functional and morphological renal changes in a Göttingen Minipig model of obesity-related and diabetic nephropathy

Obesity-related glomerulopathy and diabetic nephropathy (DN) are serious complications to metabolic syndrome and diabetes. The purpose was to study effects of a fat, fructose and cholesterol-rich (FFC) diet with and without salt in order to induce hypertension on kidney function and morphology in Göttingen Minipigs with and without diabetes. Male Göttingen Minipigs were divided into 4 groups: SD (standard diet, n = 8), FFC (FFC diet, n = 16), FFC-DIA (FFC diet + diabetes, n = 14), FFC-DIA + S (FFC diet with extra salt + diabetes, n = 14). Blood and urine biomarkers, glomerular filtration rate (GFR), blood pressure (BP) and resistive index (RI) were evaluated after 6-7 months (T1) and 12-13 months (T2). Histology, electron microscopy and gene expression (excluding FFC-DIA + S) were evaluated at T2. All groups fed FFC-diet displayed obesity, increased GFR and RI, glomerulomegaly, mesangial expansion (ME) and glomerular basement membrane (GBM) thickening. Diabetes on top of FFC diet led to increased plasma glucose and urea and proteinuria and tended to exacerbate the glomerulomegaly, ME and GBM thickening. Four genes (CDKN1A, NPHS2, ACE, SLC2A1) were significantly deregulated in FFC and/or FFC-DIA compared to SD. No effects on BP were observed. Göttingen Minipigs fed FFC diet displayed some of the renal early changes seen in human obesity. Presence of diabetes on top of FFC diet exacerbated the findings and lead to changes resembling the early phases of human DN.

Characteristic changes in plasma glutamate levels and free amino acid profiles in Japanese patients with type 1 diabetes mellitus

AIMS/INTRODUCTION

In addition to absolute insulin deficiency, dysregulated glucagon in type 1 diabetes is considered pathophysiologically important. Previously, we confirmed the presence of dysregulated glucagon in Japanese patients with type 1 diabetes, and found a significant correlation between plasma glucagon and blood urea nitrogen levels, suggesting an association between glucagon and amino acid metabolism. In this study, we evaluated plasma amino acid levels in Japanese patients with type 1 diabetes in the context of their functional relationship with glucagon.

MATERIALS AND METHODS

We assessed plasma free amino acid levels using liquid chromatography-mass spectrometry in 77 Japanese patients with type 1 diabetes, and statistically analyzed their characteristics and relationships with clinical parameters, including glucagon.

RESULTS

Participants with type 1 diabetes showed a large decrease in glutamate levels together with a characteristic change in plasma free amino acid profiles. The network structural prediction analyses showed correlations between each amino acid and glucagon in type 1 diabetes.

CONCLUSIONS

Participants with type 1 diabetes showed characteristic changes in plasma glutamate levels and free amino acid profiles compared with controls and type 2 diabetes patients. Glucagon showed a closer correlation with amino acids than with parameters of glucose metabolism, suggesting that type 1 diabetes includes dysregulation in amino acids through dysregulated glucagon from remaining pancreatic α-cells, together with that in glucose by insulin deficiency.

Beginning of a new era in glucagon research: Breakthrough by the new glucagon assay

There is a new concept of diabetes as a "comprehensive nutrition disorder", caused due to both insulin and glucagon dysregulation. Dysregulated glucagon secretion in α-cells exacerbates multiple metabolic disorders: glycemic control and amino acid metabolism, together with insulin deficiency.