Central role of the ß-cell in driving regression of diabetes after liver transplantation in cirrhotic patients.

BACKGROUND & AIMS: Diabetes occurring as a direct consequence of loss of liver function is usually characterized by non-diabetic fasting plasma glucose (FPG) and haemoglobin A1c (HbA1c) levels and should regress after orthotopic liver transplantation (OLT). This observational, longitudinal study investigated the relationship between the time-courses of changes in all 3 direct determinants of glucose regulation, i.e., ß-cell function, insulin clearance and insulin sensitivity, and diabetes regression after OLT. METHODS: Eighty cirrhotic patients with non-diabetic FPG and HbA1c levels underwent an extended oral glucose tolerance test (OGTT) before and 3, 6, 12 and 24 months after OLT. The OGTT data were analysed with a mathematical model to estimate derivative control (DC) and proportional control (PC) of ß-cell function and insulin clearance (which determine insulin bioavailability), and with the Oral Glucose Insulin Sensitivity (OGIS)-2 h index to estimate insulin sensitivity. RESULTS: At baseline, 36 patients were diabetic (45%) and 44 were non-diabetic (55%). Over the 2-year follow-up, 23 diabetic patients (63.9%) regressed to non-diabetic glucose regulation, whereas 13 did not (36.1%); moreover, 4 non-diabetic individuals progressed to diabetes (9.1%), whereas 40 did not (90.9%). Both DC and PC increased in regressors (from month 3 and 24, respectively) and decreased in progressors, whereas they remained stable in non-regressors and only PC decreased in non-progressors. Insulin clearance increased in all groups, apart from progressors. Likewise, OGIS-2 h improved at month 3 in all groups, but thereafter it continued to improve only in regressors, whereas it returned to baseline values in the other groups. CONCLUSIONS: Increased insulin bioavailability driven by improved ß-cell function plays a central role in favouring diabetes regression after OLT, in the presence of a sustained improvement of insulin sensitivity. LAY SUMMARY: Diabetes occurring in cirrhosis as a direct consequence of loss of liver function should regress after transplantation of a new functioning liver, though the pathophysiological mechanisms are unclear. This is the first study evaluating the contribution of all 3 direct determinants of insulin-dependent glucose regulation using a sophisticated mathematical model. Results show that ß-cell function is the key process governing favourable or detrimental changes in glucose regulation in cirrhotic patients undergoing transplantation, pointing to the need to develop therapies to sustain ß-cell function in these individuals. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02038517.

Management of diabetes mellitus in patients undergoing liver transplantation.

Diabetes is a common feature in cirrhotic individuals both before and after liver transplantation and negatively affects prognosis. Certain aetiological agents of chronic liver disease and loss of liver function per se favour the occurrence of pre-transplant diabetes in susceptible individuals, whereas immunosuppressant treatment, changes in lifestyle habits, and donor- and procedure-related factors contribute to diabetes development/persistence after transplantation. Challenges in the management of pre-transplant diabetes include the profound nutritional alterations characterizing cirrhotic individuals and the limitations to the use of drugs with liver metabolism. Special issues in the management of post-transplant diabetes include the diabetogenic potential of immunosuppressant drugs and the increased cardiovascular risk characterizing solid organ transplant survivors. Overall, the pharmacological management of cirrhotic patients undergoing liver transplantation is complicated by the lack of specific guidelines reflecting the paucity of data on the impact of glycaemic control and the safety and efficacy of anti-hyperglycaemic agents in these individuals.

Impaired glucose metabolism in subjects with the Williams-Beuren syndrome: A five-year follow-up cohort study.

OBJECTIVE: The Williams-Beuren syndrome (WS) is associated with impaired glucose metabolism (IGM) early in adulthood. However, the pathophysiology of IGM remains poorly defined, due to the lack of longitudinal studies investigating the contribution of ß-cell dysfunction and impaired insulin sensitivity. This study aimed at assessing incidence of IGM and the underlying mechanisms in WS adults. METHODS: This observational, longitudinal (5-year), cohort study enrolled thirty-one consecutive WS subjects attending a tertiary referral center. An oral glucose tolerance test (OGTT) was performed yearly and used to classify patients as normal or IGM, including impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) and diabetes mellitus (DM), and to calculate surrogate measures of insulin secretion and/or sensitivity. RESULTS: IGM patients were 18 (58.1%, three DM) at baseline and 19 (61.3%, five DM) at end-of-follow-up. However, 13 individuals changed category of glucose homeostasis in both directions during follow-up (8 progressors, 5 regressors) and 18 did not (8 non-progressors, 10 non-regressors). New cases of IGM and DM were 11.1 and 2.53 per 100 persons-year, respectively, and were treated non-pharmacologically. In the whole cohort and, to a higher extent, in progressors, indices of early-phase insulin secretion and insulin sensitivity decreased significantly from baseline to end-of-follow-up, with concurrent reduction of the oral disposition index and insulin secretion-sensitivity index-2 (ISSI-2), compensating insulin secretion for the level of insulin resistance. No baseline measure independently predicted progression, which correlated with change from baseline in ISSI-2. Compared with patients with normal glucose homeostasis, IGT subjects had impaired insulin sensitivity, whereas insulin secretion was reduced only in those with IFG+IGT or DM. CONCLUSIONS: IGM incidence is high in young adults with WS, suggesting the need of early screening and timed intervention. As in classical type 2 diabetes, impaired insulin sensitivity and ß-cell dysfunction contribute, in this sequence, to progression to IGM and DM.

Basal and stimulated calcitonin levels in patients with type 2 diabetes did not change during 1 year of Liraglutide treatment.

BACKGROUND AND AIMS: The administration of Liraglutide, a long-acting GLP-1 receptor (GLP-1R) agonist, is associated with C-cell adenomas and carcinomas in rats. In humans, GLP-1R is highly expressed in C-cells hyperplasia (CCH) and in medullary thyroid cancer (MTC), though no changes in basal serum calcitonin (bCT) levels were recorded in type 2 diabetic (T2DM) patients treated with Liraglutide. To diagnose the possible development of CCH during Liraglutide treatment, we evaluated CT levels stimulated by calcium test (sCT). MATERIALS AND METHODS: bCT and sCT and metabolic and anthropometric parameters were evaluated in 26 T2DM patients at baseline and at 1, 3, 6 and 12 months of treatment. RESULTS: In all patients, bCT remained within the normal range during the entire study period. In females and males, the higher sCT values were reached after 3 months and 1 month, respectively, with a progressive reduction at 6-12 months. The greater decrease of HbA1c values was reached at 3 months, while body weight and waist circumference decreased over the first 4 weeks of therapy. Lipase levels significantly increased, with a peak value at 1 month. CONCLUSION: The chronic administration of Liraglutide did not lead to statistically significant variations in both bCT and sCT. Stimulated CT levels increased, though always below the normal range, during the first 1-3 months of treatment, and progressively decreased to baseline levels. This finding is consistent with the effects recorded at the glycometabolic level, and suggests the possible induction of a drug tolerance involving also the C cells and thus preventing CCH.