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The current board of the interassociative Italian association of medical diabetologists (AMD)/Italian society of diabetology (SID) Diabetes and Pregnancy Italian Study Group commented about two recent papers published in the New England Journal of Medicine that investigated the screening and diagnostic methods for gestational diabetes mellitus (GDM). It is well recognized that effective screening and accurate, early diagnosis of GDM contributes to better management of these women in order to reduce adverse maternal and fetal/neonatal outcomes. However, there is worldwide controversy concerning which screening (selective or universal; one step or two steps) and which diagnostic criteria (glucose thresholds) are appropriate. The main findings of these papers are discussed along with their implications for the management of pregnant women., Competing Interests: Conflict of interest All authors declare no conflict of interest., (Copyright © 2023 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.)

Background and Aim: Insulin resistance is a main feature, and possibly a pathogenic factor, of non-alcoholic fatty liver disease. It is usually measured on glucose metabolism; the effects on amino acid regulation have never been assessed. In particular, no data are available on insulin-dependent branched-chain amino acid metabolism, which is under insulin control., Materials and Methods: We measured amino acid disappearance from plasma during an euglycemic glucose clamp in 39 biopsy-proven non-alcoholic fatty liver disease patients and in ten control subjects. A primed-constant infusion of insulin (constant rate, 40 mU/m2 per min for 2 h) was used to raise plasma insulin to approximately 100 mU/l. Euglycemia was maintained by a variable glucose infusion, a measure of tissue insulin sensitivity. Plasma amino acids were assayed during the clamp after ninhidrin derivatization., Results: Fasting plasma amino acids were similar in the two groups. Steady-state insulin levels were significantly higher in non-alcoholic fatty liver disease patients, whereas tissue sensitivity to insulin was reduced by 50%. The plasma disappearance of branched-chain amino acids, as well as the disappearance of the sum of glutamine and glutamate and that of serine were significantly reduced in non-alcoholic fatty liver disease. Differences were maintained after adjustment for steady-state insulin, and correlated with reduced tissue sensitivity to glucose., Conclusion: Insulin resistance in non-alcoholic fatty liver disease patients also affects amino acid metabolism, especially for amino acids involved in peripheral muscle nitrogen exchange. The metabolic effects of altered protein/amino acid metabolism must be considered.