Increased plasma concentrations of glucagon (hyperglucagonemia) are reported in patients with type 2 diabetes (T2D) and act as a prediabetogenic risk factor. Emerging evidence suggests that hepatic ...steatosis in obesity is causing a condition of glucagon resistance towards amino acid catabolism, resulting in a compensatory hyperglucagonemia. We investigated the presence of hyperglucagonemia in individuals with biopsy-verified metabolic dysfunction-associated steatotic liver disease (MASLD), and whether body mass index (BMI), T2D, hepatic steatosis and/or fibrosis contribute to this relationship. To dissect potential mechanisms, we determined hepatic gene expression related to amino acid transport and catabolism. Individuals with MASLD had hyperglucagonemia (controls ( n=74) versus MASLD ( n=106); median Q1, Q3; 4 3, 7 versus 8 6, 13 pM), p<.0001) and were glucagon resistant (assessed by the glucagon-alanine index) (1.3 0.9, 2.1 versus 3.3 2.1, 5.3 pM*mM, p<.0001). These changes associated with hepatic steatosis ( p<.001, R 2 >.25) independently of BMI, sex, age, and T2D. Plasma levels of glucagon were similar in individuals with MASLD when stratified on T2D status (MASLD-T2D ( n=52) versus MASLD+T2D ( n=54); 8 6, 11 versus 8 6, 13 pM, p=.34) and hepatic fibrosis (MASLD+F0 ( n=25) versus MASLD+F1-F3 ( n=67); 8.4 7.0, 13.3 versus 7.9 5.2, 11.6 pM, p=.43). Obesity (BMI=30kg/m 2 ) did not alter glucagon levels ( p=.65) within groups (control/MASLD). The mRNA expression of proteins involved in amino acid transport and catabolism were downregulated in MASLD. Thus, prediabetogenic hyperglucagonemia is present in individuals with biopsy-verified MASLD, and hepatic steatosis partially drives hyperglucagonemia and glucagon resistance, irrespective of T2D, BMI, and hepatic fibrosis.
Metabolic dysfunction in patients with metabolic fatty liver disease (MAFLD) may increase the risk for diabetes development. The liver is essential for the postprandial control of our metabolism and ...hormonal response, yet most studies focus on fasting conditions. We therefore studied the fasting and postprandial phase in individuals with biopsy-proven nonalcoholic fatty liver disease (NAFLD, (n = 9, mean age 50 y, mean BMI 35 kg/m2, no/mild fibrosis) , cirrhosis (n = 10, age 62 y, BMI 32 kg/m2, CHILD A/B) and healthy controls (n = 10, age 23, BMI 25 kg/m2) , randomized 1:1 to fasting or Nutridrink (Nutricia, 300 kcal) . None of the postprandial patients had type 2 diabetes (T2D) . In the NAFLD/cirrhosis groups, 17/classified as MAFLD. Peripheral blood samples were collected at 0, 15, 45, 60, 90 and 120 minutes. At time point 60, a transjugular liver biopsy and liver vein blood were taken. Levels of glucose, insulin, C-peptide, glucagon, and fibroblast growth factor 21 (FGF21) were measured in peripheral blood, glucagon and FGF21 also in liver vein blood. Postprandial peak glucose and C-peptide was increased in NAFLD and cirrhosis compared with healthy (mean peak glucose (mM) 7, 10, 6; mean peak C-peptide (pM) 2675, 3340, 1689, respectively) . The postprandial incremental AUC for insulin was significantly increased in patients with NAFLD compared to healthy. Patients with NAFLD and cirrhosis had hyperglucagonemia, a phenotype related to prediabetes. FGF21 was increased in NAFLD and cirrhosis and correlated to age (r= .61, P = .001) and fasting glucose (r = .54, P = .006) . Glucagon levels were higher in liver vein compared to peripheral blood, while FGF21 levels were similar in both compartments.
In summary, patients with NAFLD and cirrhosis without T2D showed significant metabolic dysfunction after a standardized meal compared to healthy controls. We found impaired glucose tolerance, hyperinsulinemia and hyperglucagonemia in both NAFLD and cirrhosis, suggesting a condition of prediabetes in patients with MAFLD.
Disclosure
J. Grandt: None. A.H. Jensen: None. M.P. Werge: None. E.B. Rashu: None. A. Junker: None. L. Hobolth: None. C. Mortensen: None. M. Vyberg: None. R. Serizawa: Consultant; Merck Sharp & Dohme Corp. L. Gluud: Advisory Panel; Novo Nordisk. Consultant; Pfizer Inc. Research Support; Alexion Pharmaceuticals, Inc., Gilead Sciences, Inc., Novo Nordisk, Sobi. N.J. Wewer Albrechtsen: Research Support; Mercodia AB, Novo Nordisk, Regeneron Pharmaceuticals Inc. Speaker's Bureau; Merck & Co., Inc., Mercodia AB.
Funding
Nicolai J. Wewer Albrechtsen was financed by NNF Excellence Emerging Investigator Grant – Endocrinology and Metabolism (Application No. NNF19OC0055001) , EFSD Future Leader Award (NNF21SA0072746) and DFF Sapere Aude.
Gluco-regulatory disturbances such as hepatic insulin resistance, hyperinsulinemia and prediabetes are commonly present in patients with nonalcoholic fatty liver disease (NAFLD) and those individuals ...may over time develop full-blown type 2 diabetes. Chronic liver diseases such as NAFLD and autoimmune liver diseases (AILDs) are heterogenous but may affect glucose-metabolism similarly. It is, however, unknown if AILDs—such as primary biliary cholangitis (PBC) —display gluco-regulatory impairments. We therefore investigated glucose and hormonal responses during a 75 g oral glucose tolerance test (OGTT) in patients with biopsy-verified, non-cirrhotic PBC (n = 9, age 55 ± y (mean ± sd) , BMI 31 ± 6 kg/m2 (mean ± sd)) , NAFLD (n = 6, age 38 ± 17 y, BMI 31 ± 4 kg/m2) and healthy controls (n = 8, age 23 ± 3 y, BMI 23 ± 2 kg/m2) . None of the participants had diabetes. In the PBC group, 3 had NAFLD. Fasting glucose, c-peptide and insulin levels were significantly increased in PBC and NAFLD compared with healthy controls (mean (95 % CI) ; glucose (mM) 5.6 (4.7-6.7) , 5.7 (5.2-6.1) , 4.7 (3.9-5.6) ; c-peptide (pM) 993 (556-1773) , 1334 (1036-1719) , 483 (268-869) ; insulin (pM) 98 (33-298) , 166 (103-267) , 43 (14-136) ; respectively) . Hepatic insulin resistance (reflected by fasting homeostasis model assessment of insulin resistance (HOMA-IR)) was present in PBC (mean 4.0 (95 % CI 1.2-13.9)) and NAFLD (7.0 (4.1-11.9)) but not in healthy controls (1.5 (0.4-5.4)) . There was no significant difference in glucose levels between the groups. Beta-cell secretion (c-peptide) was significantly increased in PBC and NAFLD. Insulin responses were higher in PBC and NAFLD compared with healthy but only reached statistical significance in NAFLD. Our data suggest that patients with PBC have gluco-regulatory disturbances including hepatic insulin resistance and impaired beta-cell function. Metabolic dysfunction of PBC may be underestimated and warrant further investigation.
Disclosure
A.H. Jensen: None. H. Ytting: Other Relationship; Gilead Sciences, Inc. J. Grandt: None. M.P. Werge: None. E.B. Rashu: None. L.E. Hetland: None. A. Junker: None. L. Hobolth: None. C. Mortensen: None. F. Tofteng: None. M. Vyberg: None. R. Serizawa: Consultant; Merck Sharp & Dohme Corp. L. Gluud: Advisory Panel; Novo Nordisk. Consultant; Pfizer Inc. Research Support; Alexion Pharmaceuticals, Inc., Gilead Sciences, Inc., Novo Nordisk, Sobi. N.J. Wewer Albrechtsen: Research Support; Mercodia AB, Novo Nordisk, Regeneron Pharmaceuticals Inc. Speaker’s Bureau; Merck & Co., Inc., Mercodia AB.
Funding
Nicolai J. Wewer Albrechtsen were financed by NNF Excellence Emerging Investigator Grant – Endocrinology and Metabolism (Application No. NNF19OC0055001) , EFSD Future Leader Award (NNF21SA0072746) and DFF Sapere Aude
Autoimmune liver diseases are associated with an increased risk of diabetes, yet the underlying mechanisms remain unknown. In this cross-sectional study, we investigated the glucose-regulatory ...disturbances in patients with autoimmune hepatitis (AIH, n=19), primary biliary cholangitis (PBC, n=15), and primary sclerosing cholangitis (PSC, n=6). Healthy individuals (n=24) and patients with metabolic dysfunction-associated steatotic liver disease (MASLD, n=18) were included as controls. Blood samples were collected during a 120 min oral glucose tolerance test. We measured the concentrations of glucose, C-peptide, insulin, glucagon, the two incretin hormones glucose insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1). We calculated the homeostasis model assessment of insulin resistance (HOMA-IR), whole body insulin resistance (Matsuda index), insulin clearance, and insulinogenic index. All patient groups had increased fasting plasma glucose and impaired glucose responses compared with healthy controls. Beta-cell secretion was increased in AIH, PBC, and MASLD but not in PSC. AIH and MASLD patients had hyperglucagonemia and hepatic, as well as peripheral, insulin resistance and decreased insulin clearance, resulting in hyperinsulinemia. Patients with autoimmune liver disease had an increased GIP response, and those with AIH or PBC had an increased GLP-1 response. Our data demonstrate that the mechanism underlying glucose disturbances in patients with autoimmune liver disease differs from that underlying MASLD, including compensatory incretin responses in patients with autoimmune liver disease. Our results suggest that glucose disturbances are present at an early stage of the disease.
Increased plasma levels of glucagon (hyperglucagonaemia) promote diabetes development but is also observed in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). This may ...reflect hepatic glucagon resistance towards amino acid catabolism. A clinical test for measuring glucagon resistance has not been validated. We evaluated our glucagon sensitivity (GLUSENTIC) test, consisting of two study days: a glucagon injection and measurements of plasma amino acids, and an infusion of mixed amino acids and subsequent calculation of the GLUSENTIC index (primary outcome measure) from measurements of glucagon and amino acids. To distinguish glucagon-dependent from insulin-dependent actions on amino acid metabolism, we also studied patients with type 1 diabetes (T1D). The delta-decline in total amino acids was 49% lower in MASLD following exogenous glucagon (p=0.01), and the calculated GLUSENTIC index was 34% lower in MASLD (p<0.0001), but not T1D (p>0.99). In contrast, glucagon-induced glucose increments were similar in controls and MASLD (p=0.41). The GLUSENTIC test and index may be used to measure glucagon resistance in individuals with obesity and MASLD.
Glucagon is essential for glucose control and increased levels of glucagon (hyperglucagonemia) observed in patients with type 2 diabetes contribute to their hyperglycemia. Recently, hyperglucagonemia ...has also been found in individuals with non-alcoholic fatty liver disease (NAFLD) as well as impaired actions of glucagon on amino acid catabolism. Whether glucagon actions on hepatic glucose production are impaired is unknown. We investigated the acute effects of a single bolus of glucagon (0.2mg) on glucose dynamics in 18 normoglycemic individuals (age: 51±3 years, BMI; 31± 0.8kg/m2, hepatic fat content: 20±2%, fasting glucose: 5.5±0.1mM) with magnetic resonance imaging verified NAFLD and 22 controls (age: 38±3 years, BMI; 24± 0.8kg/m2, hepatic fat content: 4±0.1%, fasting glucose: 5.0±0.1mM) . On a separate day, a mixture of amino acids (14 g/L; 331 mg/min/kg body weight) was infused intravenously for 45min to evaluate the actions of endogenous glucagon on glucose dynamics. Glucose levels (see figure) were significantly increased in individuals with NAFLD 60min after the glucagon bolus and during the amino acid infusion with a maximal difference of 0.5mM 30min into the infusion. These data suggest that the actions of glucagon on hepatic glucose production are not impaired by NAFLD. Therefore, the hyperglucagonemia in patients with NAFLD may constitute a diabetogenic risk factor.
Disclosure
S.Kjeldsen: None. H.Vilstrup: None. F.V.Schiødt: Advisory Panel; Novo Nordisk. A.Møller: None. E.B.Rashu: None. L.Gluud: Advisory Panel; Novo Nordisk, Consultant; Pfizer Inc., Research Support; Alexion Pharmaceuticals, Inc., Gilead Sciences, Inc., Novo Nordisk, Sobi. S.B.Haugaard: None. J.J.Holst: Advisory Panel; Novo Nordisk, Board Member; Antag Therapeutics, Bainan Biotech. J.Rungby: Advisory Panel; Abbott, Boehringer Ingelheim International GmbH, Speaker’s Bureau; AstraZeneca, Bayer AG, Novo Nordisk, Pfizer Inc. N.J.Wewer albrechtsen: Research Support; Mercodia AB, Novo Nordisk, Regeneron Pharmaceuticals Inc., Speaker’s Bureau; Merck & Co., Inc., Mercodia AB. N.J.Jensen: None. M.Nilsson: None. N.Heinz: None. J.D.Nybing: None. F.H.Linden: None. E.Høgh-schmidt: n/a. M.P.Boesen: None. S.Madsbad: None.
Funding
NNF Excellence Emerging Investigator Grant – Endocrinology and Metabolism (Application No. NNF19OC0055001) , EFSD Future Leader Award (NNF21SA0072746) and DFF Sapere Aude.
Aims
Sacubitril/valsartan is a neprilysin‐inhibitor/angiotensin II receptor blocker used for the treatment of heart failure. Recently, a post‐hoc analysis of a 3‐year randomized controlled trial ...showed improved glycaemic control with sacubitril/valsartan in patients with heart failure and type 2 diabetes. We previously reported that sacubitril/valsartan combined with a dipeptidyl peptidase‐4 inhibitor increases active glucagon‐like peptide‐1 (GLP‐1) in healthy individuals. We now hypothesized that administration of sacubitril/valsartan with or without a dipeptidyl peptidase‐4 inhibitor would lower postprandial glucose concentrations (primary outcome) in patients with type 2 diabetes via increased active GLP‐1.
Methods
We performed a crossover trial in 12 patients with obesity and type 2 diabetes. A mixed meal was ingested following five respective interventions: (a) a single dose of sacubitril/valsartan; (b) sitagliptin; (c) sacubitril/valsartan + sitagliptin; (d) control (no treatment); and (e) valsartan alone. Glucose, gut and pancreatic hormone responses were measured.
Results
Postprandial plasma glucose increased by 57% (incremental area under the curve 0‐240 min) (p = .0003) and increased peak plasma glucose by 1.7 mM (95% CI: 0.6‐2.9) (p = .003) after sacubitril/valsartan compared with control, whereas postprandial glucose levels did not change significantly after sacubitril/valsartan + sitagliptin. Glucagon, GLP‐1 and C‐peptide concentrations increased after sacubitril/valsartan, but insulin and glucose‐dependent insulinotropic polypeptide did not change.
Conclusions
The glucose‐lowering effects of long‐term sacubitril/valsartan treatment reported in patients with heart failure and type 2 diabetes may not depend on changes in entero‐pancreatic hormones. Neprilysin inhibition results in hyperglucagonaemia and this may explain the worsen glucose tolerance observed in this study.
ClinicalTrials.gov (NCT03893526).
Glucagon regulates hepatic glucose production and hyperglucagonemia contributes to diabetes. Equally important, glucagon may regulate amino acid (AA) levels that in turn control glucagon secretion. ...Hepatic steatosis may uncouple glucagon's effect on AA metabolism causing impaired actions of glucagon (resistance) on AA metabolism but not glucose production, thereby creating a diabetogenic circle. In order to quantify glucagon's effect on AA metabolism, we developed and evaluated a glucagon sensitivity test. The test consists of a bolus-infusion of glucagon (200 μg) and an AA infusion (330 mg/min/kg body weight for 45 min) on two separate days following an overnight fast. Liver fat was measured using magnetic resonance imaging. Preliminary data from six individuals without diabetes (HbA1c < 48mmol/mol) including three lean controls (CON) (mean ± SD; Age: 32 ± 7 years, liver fat: 4.1 ± 1 %, BMI; 22 ± 2 kg/m2) and three individuals with obesity (OBE) (47 ± 12 years, 12 ± 6 %, 30 ± 4 kg/m2) are presented. A glucagon injection reduced AA levels 29% less in OBE compared to CON (dAUC0-120min; 41 ± 6 vs. 29 ± 10 mmol/L x min) during the fasted state. AA levels increased 33% more in OBE compared to CON during an AA infusion (iAUC0-45min; 118 ± 28 vs. 89 ± 12 mmol/L x min). We conclude that glucagon sensitivity towards AA metabolism may be evaluated by a bolus-infusion of glucagon and an AA infusion, and that hepatic steatosis may cause glucagon resistance.
Fatty liver disease has mainly been characterized under fasting conditions. However, as the liver is essential for postprandial homeostasis, identifying postprandial disturbances may be important. ...Here, we investigated postprandial changes in markers of metabolic dysfunction between healthy individuals, obese individuals with non‐alcoholic fatty liver disease (NAFLD) and patients with cirrhosis. We included individuals with biopsy‐proven NAFLD (n = 9, mean age 50 years, mean BMI 35 kg/m2, no/mild fibrosis), cirrhosis with hepatic steatosis (n = 10, age 62 years, BMI 32 kg/m2, CHILD A/B) and healthy controls (n = 10, age 23, BMI 25 kg/m2), randomized 1:1 to fasting or standardized mixed meal test (postprandial). None of the patients randomized to mixed meal test had type 2 diabetes (T2D). Peripheral blood was collected for 120 min. After 60 min, a transjugular liver biopsy and liver vein blood was taken. Plasma levels of glucose, insulin, C‐peptide, glucagon, and fibroblast growth factor 21 (FGF21) were measured. Postprandial peak glucose and C‐peptide were significantly increased in NAFLD, and cirrhosis compared with healthy. Patients with NAFLD and cirrhosis had hyperglucagonemia as a potential sign of glucagon resistance. FGF21 was increased in NAFLD and cirrhosis independent of sampling from the liver vein versus peripheral blood. Glucagon levels were higher in the liver vein compared with peripheral blood. Patients with NAFLD and cirrhosis without T2D showed impaired glucose tolerance, hyperinsulinemia, and hyperglucagonemia after a meal compared to healthy individual. Postprandial characterization of patients with NAFLD may be important to capture their metabolic health.
Postprandial state is explored in patients with fatty liver disease highlighting the importance of evaluting fasting and postprandial conditions in metabolic diseases.
A physiological feedback system exists between hepatocytes and the alpha cells, termed the liver-alpha cell axis and refers to the relationship between amino acid-stimulated glucagon secretion and ...glucagon-stimulated amino acid catabolism. Several reports indicate that non-alcoholic fatty liver disease (NAFLD) disrupts the liver-alpha cell axis, because of impaired glucagon receptor signaling (glucagon resistance). However, no experimental test exists to assess glucagon resistance in humans. The objective was to develop an experimental test to determine glucagon sensitivity with respect to amino acid and glucose metabolism in humans. The proposed glucagon sensitivity test (comprising two elements: 1) i.v. injection of 0.2 mg glucagon and 2) infusion of mixed amino acids 331 mg/hour/kg) is based on nine pilot studies which are presented. Calculation of a proposed glucagon sensitivity index with respect to amino acid catabolism is also described. Secondly, we describe a complete study protocol (GLUSENTIC) according to which the glucagon sensitivity test will be applied in a cross-sectional study currently taking place. 65 participants including 20 individuals with a BMI 18.6–25 kg/m2, 30 individuals with a BMI ≥ 25–40 kg/m2, and 15 individuals with type 1 diabetes with a BMI between 18.6 and 40 kg/m2 will be included. Participants will be grouped according to their degree of hepatic steatosis measured by whole-liver magnetic resonance imaging (MRI). The primary outcome measure will be differences in the glucagon sensitivity index between individuals with and without hepatic steatosis. Developing a glucagon sensitivity test and index may provide insight into the physiological and pathophysiological mechanism of glucagon action and glucagon-based therapies.
•A glucagon sensitivity test towards hepatic amino acid catabolism was developed.•Pilot studies leading to the final glucagon test are presented.•A novel glucagon sensitivity index is presented.•The test may be an important tool to investigate glucagon resistance.
