Liraglutide treatment for the prevention of glucose tolerance deterioration in women with prior gestational diabetes mellitus: A 52-week randomized controlled clinical trial

AIM

We investigated the effect of 52-week treatment with liraglutide, a glucagon-like peptide 1 receptor agonist, on glucose tolerance and incretin effect in women with previous gestational diabetes mellitus (pGDM).

MATERIALS AND METHODS

Women with overweight/obesity and pGDM were randomized to once daily subcutaneous liraglutide 1.8 mg or placebo for 52 weeks. Participants underwent oral glucose tolerance test (OGTT) and isoglycaemic intravenous glucose infusion at baseline and at 52 weeks, and an additional OGTT after the drug wash-out.

RESULTS

In total, 104 women [age: mean ± SD, 38 ± 5 years; fasting plasma glucose (FPG): 5.5 ± 0.4 mmol/L; glycated haemoglobin (HbA1c): 33 ± 4 mmol/mol, bodyweight: 88.2 ± 14.8 kg, body mass index: 31.1 ± 4.3 kg/m2 ] were assigned to liraglutide (n = 49) or placebo (n = 55). Estimated treatment difference (ETD) for area under curve during OGTT was -173 (95% confidence interval -250 to -97) mmol/L × min, p < .0001, but after wash-out the difference disappeared [ETD 58 (-30 to 146) mmol/L × min, p = .536]. Liraglutide reduced FPG [ETD -0.2 (-0.4 to -0.1) mmol/L, p = .018], HbA1c [-2.2 (-3.5 to -0.8) mmol/mol, p = .018] and bodyweight [-3.9 (-6.2 to -1.6) kg, p = .012]. No change in the incretin effect was observed. The number of women with prediabetes was reduced from 64% to 10% with liraglutide vs. 50% with placebo [adjusted odds ratio 0.10 (0.03-0.32), p = .002].

CONCLUSIONS

Treatment with liraglutide for 52 weeks improved glucose tolerance, FPG, HbA1c and bodyweight in women with overweight/obesity and pGDM. Progression to prediabetes while on drug was markedly reduced, but after a 1-week drug wash-out, the effect was lost.

One Year's Treatment with the Glucagon-Like Peptide 1 Receptor Agonist Liraglutide Decreases Hepatic Fat Content in Women with Nonalcoholic Fatty Liver Disease and Prior Gestational Diabetes Mellitus in a Randomized, Placebo-Controlled Trial

Prior gestational diabetes mellitus (pGDM) is associated with increased risk of nonalcoholic fatty liver disease (NAFLD). Treatment with glucagon-like peptide 1 (GLP-1) receptor agonists has shown beneficial effects in NAFLD patients. We evaluated the effect of the GLP-1 analogue liraglutide on NAFLD features in women with pGDM. Eighty-two overweight/obese, nondiabetic women with pGDM were included. We performed abdominal ultrasound, transient elastography with controlled attenuation parameter (CAP), and blood sampling at baseline and after 1 year. Thirty-seven women were randomized to liraglutide (1.8 mg once-daily) and 45 to placebo. Based on the ultrasound scan, 18 women (22%) had ultrasound-verified NAFLD at baseline and of these, 10 (56%) received liraglutide treatment. After 1 year, eight participants no longer had steatosis, four in each treatment group. The number of participants who developed NAFLD was similar in the two treatment groups; five in the liraglutide group and six in the placebo group (p = 0.74). Compared to placebo, liraglutide reduced the CAP-assessed intrahepatic fat content (−28 (−44;−11) vs. 2 (−13;18) dB/m, p < 0.01) and body weight (−4.7 (−6.4;−2.9) vs. −1.4 (−3;0.3) kg, p < 0.01). One-year’s liraglutide treatment had no effect on the presence of ultrasound-diagnosed NAFLD in overweight/obese nondiabetic women with pGDM, but reduced body weight and steatosis assessed by transient elastography with CAP.

Glucose-Dependent Insulinotropic Polypeptide Is a Pancreatic Polypeptide Secretagogue in Humans

BACKGROUND

Glucose-dependent insulinotropic polypeptide (GIP) has been suggested to stimulate the secretion of pancreatic polypeptide (PP), an islet hormone thought to regulate gut motility, appetite, and glycemia.

OBJECTIVE

To determine whether human GIP1-42 (hGIP) stimulates PP secretion.

METHOD

As glycemia modulates the secretion of PP, we measured plasma PP concentrations from 2 studies in healthy men (n = 10) and in patients with type 2 diabetes (T2D) (n = 12), where hGIP1-42 had been administered intravenously during fasting glycemia, hyperglycemia (12 mmol/L), and insulin-induced hypoglycemia (targets: 2.5 mmol/L [healthy]; 3.5 mmol/L [T2D]). Porcine GIP1-42 (pGIP) was also infused intra-arterially in isolated porcine pancreata (n = 4).

RESULTS

Mean fasting plasma glucose concentrations were approximately 5 mmol/L (healthy) and approximately 8 mmol/L (T2D). At fasting glycemia, PP concentrations were higher during intravenous hGIP1-42 infusion compared with saline in healthy men (mean [standard error of the mean, SEM], net incremental areas under the curves (iAUCs)[0-30min], 403 [116] vs -6 [57] pmol/L × min; P = 0.004) and in patients with T2D (905 [177] vs -96 [86] pmol/L × min; P = 0.009). During hyperglycemic clamping, mean [SEM] PP concentrations were significantly higher during hGIP1-42 infusion compared with saline in patients with T2D (771 [160] vs -183 [117] pmol/L × min; P = 0.001), but not in healthy individuals (-8 [86] vs -57 [53] pmol/L × min; P = 0.69). When plasma glucose levels were declining in response to exogenous insulin, mean [SEM] PP concentrations were higher during hGIP1-42 infusion compared with saline in healthy individuals (294 [88] vs -82 [53] pmol/L × min; P = 0.0025), but not significantly higher in patients with T2D (586 [314] vs -120 [53]; P = 0.070). At target hypoglycemia, PP levels surged in both groups during both hGIP1-42 and saline infusions. In isolated pancreata, pGIP1-42 increased mean [SEM] PP output in the pancreatic venous effluent (baseline vs infusion, 24[5] vs 79 [16] pmol/min x min; P = 0.044).

CONCLUSION

GIP1-42 increases plasma PP secretion in healthy individuals, patients with T2D, and isolated porcine pancreata. Hyperglycemia blunts the stimulatory effect of hGIP1-42 in healthy individuals, but not in patients with T2D.

One-year follow-up on liraglutide treatment for prediabetes and overweight/obesity in clozapine- or olanzapine-treated patients

OBJECTIVE

Treatment with most antipsychotics is associated with an increased risk of weight gain and metabolic disturbances. In a randomized trial, we previously demonstrated that 16 weeks of glucagon-like peptide-1 receptor agonist liraglutide treatment vs. placebo significantly reduced glucometabolic disturbances and body weight in prediabetic, overweight/obese schizophrenia-spectrum disorder patients treated with clozapine or olanzapine. The aim of this study was to investigate whether the beneficial effects of the 16-week intervention were sustained beyond the intervention period.

METHOD

One year after completion of the intervention, we investigated changes in body weight, fasting glucose, glycated hemoglobin, C-peptide, and lipids comparing 1-year follow-up levels to end of treatment (week 16) and baseline (week 0) levels.

RESULTS

From end of treatment to the 1-year follow-up, body weight had increased in the liraglutide-treated group. However, compared to baseline levels, the placebo-subtracted body weight loss remained significantly reduced (-3.8 kg, 95% CI: -7.3 to -0.2, P = 0.04). Fasting glucose, glycated hemoglobin, C-peptide, and lipids had each returned to baseline levels 1 year after stopping liraglutide.

CONCLUSION

The body weight reduction during 16 weeks of liraglutide treatment was partially sustained 1 year after the intervention was completed. However, the improvements in other metabolic parameters returned to baseline levels.

Effects of liraglutide on gallbladder emptying: A randomized, placebo-controlled trial in adults with overweight or obesity

AIMS

Treatment with liraglutide 3.0 mg has been associated with gallbladder-related adverse events. To conduct a single-centre, double-blind, 12-week trial comparing the effect of 0.6 mg liraglutide and steady-state liraglutide 3.0 mg with placebo on gallbladder emptying in adults with body mass index (BMI) ≥27 kg/m² and without diabetes.

METHODS

Participants were randomized 1:1 to once-daily subcutaneous liraglutide (n = 26) or placebo (n = 26), starting at 0.6 mg with 0.6-mg weekly increments to 3.0 mg, with nutritional and physical activity counselling. A 600-kcal (23.7 g fat) liquid meal test was performed at baseline, after the first dose and after 12 weeks. The primary endpoint was the 12-week maximum postprandial gallbladder ejection fraction (GBEF_max ), measured over 240 minutes after starting the meal.

RESULTS

Baseline characteristics were similar between groups (mean ± SD overall age 47.6 ± 10.0 years, BMI 32.6 ±3.4 kg/m² , 50% women). Mean 12-week GBEF_max (treatment difference -3.7%, 95% confidence interval [CI] -13.1, 5.7) and area under the GBEF curve in the first 60 minutes (-390% × min, 95% CI -919, 140) did not differ for liraglutide 3.0 mg (n = 23) vs placebo (n = 24). The median (range) time to GBEF_max was 151 (11-240) minutes with liraglutide 3.0 mg and 77 (22-212) minutes with placebo. Similar findings were noted after the first 0.6-mg liraglutide dose. Gastrointestinal disorders, notably nausea and constipation, were the most frequently reported adverse events.

CONCLUSIONS

Treatment with liraglutide did not affect the GBEF_max but appeared to prolong the time to GBEF_max .

Women with prior gestational diabetes mellitus and prediabetes are characterised by a decreased incretin effect

AIMS/HYPOTHESIS

We investigated whether a reduced incretin effect, as observed in patients with type 2 diabetes, can be detected in high-risk individuals, such as women with prior gestational diabetes mellitus (pGDM).

METHODS

In this cross-sectional study, 102 women without diabetes with pGDM and 15 control participants without pGDM and with normal glucose tolerance (NGT) underwent a 4 h 75 g OGTT and an isoglycaemic i.v. glucose infusion (IIGI). Women with pGDM were classified as having NGT or prediabetes (impaired fasting glucose and/or impaired glucose tolerance). Insulin sensitivity was assessed using the Matsuda index and HOMA2-IR and the incretin effect was calculated from insulin responses during the study (100% × [AUC_insulin,OGTT - AUC_insulin,IIGI]/AUC_insulin,OGTT).

RESULTS

Sixty-three of the 102 women with pGDM (62%) had prediabetes (median [interquartile range]: age, 38.3 [6.5] years; BMI, 32.1 [5.8] kg/m²) and 39 women (38%) had NGT (age, 39.5 [5.6] years; BMI, 31.0 [6.7] kg/m²). Control participants (n = 15) were not significantly different from the pGDM group with regards to age (39.2 [7.4] years) and BMI (28.8 [9.2] kg/m²). Compared with women with NGT and control participants, women with prediabetes had lower insulin sensitivity, as measured by the Matsuda index (3.0 [2.4] vs 5.0 [2.6] vs 1.5 [1.8], respectively; p < 0.001). The incretin effect was 55.3% [27.8], 73.8% [19.0] and 76.7% [24.6] in women with prediabetes, women with normal glucose tolerance and control participants, respectively (p < 0.01).

CONCLUSION/INTERPRETATION

Prediabetes was highly prevalent in women with pGDM, and alterations in the incretin effect were detected in this group before the development of type 2 diabetes.

TRIAL REGISTRATION

clinicaltrialsregister.eu 2012-001371-37-DK.

Effect of Liraglutide Treatment on Prediabetes and Overweight or Obesity in Clozapine- or Olanzapine-Treated Patients With Schizophrenia Spectrum Disorder: A Randomized Clinical Trial

IMPORTANCE

Compared with the general population, patients with schizophrenia have a 2- to 3-fold higher mortality rate primarily caused by cardiovascular disease. Previous interventions designed to counteract antipsychotic-induced weight gain and cardiometabolic disturbances reported limited effects.

OBJECTIVES

To determine the effects of the glucagon-like peptide-1 receptor agonist liraglutide added to clozapine or olanzapine treatment of schizophrenia spectrum disorders.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical double-blind trial enrolled participants at 2 clinical sites in Denmark. Of 214 eligible participants with a schizophrenia spectrum disorder, 103 were randomized to liraglutide or placebo. Participants received stable treatment with clozapine or olanzapine, were overweight or obese, and had prediabetes. Data were collected from May 1, 2013, through February 25, 2016.

INTERVENTIONS

Treatment for 16 weeks with once-daily subcutaneous injection of liraglutide or placebo. Trial drug therapy was titrated during the first 2 weeks of the study.

MAIN OUTCOMES AND MEASURES

The primary end point was change in glucose tolerance estimated by a 75-g oral glucose tolerance test result. Secondary end points included change in body weight and cardiometabolic parameters.

RESULTS

Of the 103 patients undergoing randomization (60 men [58.3%] and 43 women [41.7%]), 97 were included in the efficacy analysis, with a mean (SD) age of 42.5 (10.5) years and mean (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) of 33.8 (5.9). The liraglutide and placebo groups had comparable characteristics (mean [SD] age, 42.1 [10.7] vs 43.0 [10.5] years; 30 men in each group; mean [SD] body mass index, 33.7 [5.1] vs 33.9 [6.6]). A total of 96 randomized participants (93.2%) completed the trial. Glucose tolerance improved in the liraglutide group compared with the placebo group (P < .001). Altogether, 30 liraglutide-treated participants (63.8%) developed normal glucose tolerance compared with 8 placebo-treated participants (16.0%) (P < .001; number needed to treat, 2). Body weight decreased with liraglutide compared with placebo (-5.3 kg; 95% CI, -7.0 to -3.7 kg). Reductions in waist circumference (-4.1 cm; 95% CI, -6.0 to -2.3 cm), systolic blood pressure (-4.9 mm Hg; 95% CI, -9.5 to -0.3 mm Hg), visceral fat (-250.19 g; 95% CI, -459.9 to -40.5 g), and low-density lipoprotein levels (-15.4 mg/dL; 95% CI, -23.2 to -7.7 mg/dL) occurred with liraglutide compared with placebo. Adverse events with liraglutide affected mainly the gastrointestinal tract.

CONCLUSIONS AND RELEVANCE

Liraglutide significantly improved glucose tolerance, body weight, and cardiometabolic disturbances in patients with schizophrenia spectrum disorders treated with clozapine or olanzapine.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01845259.

Efficacy and safety of fixed-ratio combination of insulin degludec and liraglutide (IDegLira) for the treatment of type 2 diabetes

INTRODUCTION

Type 2 diabetes (T2D) is a progressive disease with increasing prevalence in most countries. The majority of patients with T2D have inadequate glycaemic control, which increases the risk of diabetic complications later in life. New therapies with improved safety profiles are required to tackle the progressive nature of T2D. Areas covered: The efficacy and safety profile of IDegLira - a once-daily, fixed-ratio combination of insulin degludec and liraglutide, a glucagon-like peptide-1 receptor agonist (GLP-1RA), for the treatment of T2D - has been extensively evaluated. IDegLira's phase 3 clinical trial programme builds upon the clinical programmes of its mono-components, and their cardiovascular outcomes trials. The results are described here, focusing on different patient populations and compared with alternative insulin regimens. Expert opinion: IDegLira provides superior glycaemic control and mitigates the primary adverse effects associated with insulin therapy (weight gain and hypoglycaemia) and GLP-1RAs (gastrointestinal side effects) with no indication of additive effects. Accordingly, co-formulations such as IDegLira are likely to be increasingly preferred over stepwise addition and titration of the individual agents in the management of T2D.

Nonalcoholic Fatty Liver Disease Is Prevalent in Women With Prior Gestational Diabetes Mellitus and Independently Associated With Insulin Resistance and Waist Circumference

OBJECTIVE

Type 2 diabetes increases the risk of nonalcoholic fatty liver disease (NAFLD), which is a potentially reversible condition but is also associated with progressive fibrosis and cirrhosis. Women with prior gestational diabetes mellitus (pGDM) have a higher risk for NAFLD.

RESEARCH DESIGN AND METHODS

One hundred women without diabetes who had pGDM (median [interquartile range]: age 38.6 [6.4] years; BMI 31.0 [6.2] kg/m²) and 11 healthy control subjects without NAFLD (age 37.9 [7.8] years; BMI 28.1 [0.8] kg/m²) underwent a 75-g oral glucose tolerance test (OGTT), DXA whole-body scan, and ultrasonic evaluation of hepatic steatosis.

RESULTS

Twenty-four (24%) women with pGDM had NAFLD on the basis of the ultrasound scan. None had cirrhosis. Women with NAFLD had a higher BMI (P = 0.0002) and waist circumference (P = 0.0003), increased insulin resistance (P = 0.0004), and delayed suppression of glucagon after the OGTT (P < 0.0001), but NAFLD was not associated with the degree of glucose intolerance (P = 0.2196). Visceral fat mass differed among the three groups, with the NAFLD group having the highest amount of fat and the control subjects the lowest (P = 0.0003). By logistic regression analysis, insulin resistance (P = 0.0057) and waist circumference (P = 0.0109) were independently associated with NAFLD.

CONCLUSIONS

NAFLD was prevalent in this cohort of relatively young and nonseverely obese women with pGDM who are considered healthy apart from their increased risk for diabetes. Insulin resistance and a larger waist circumference were independently associated with the presence of NAFLD, whereas glucose intolerance was not.

Fixed combination of insulin and a glucagon-like peptide-1 analog for the treatment of type 2 diabetes, exemplified by insulin degludec and liraglutide

Insulin therapy in the management of Type 2 diabetes is often postponed and/or not adequately intensified to maintain glycemic control because of the risk of weight gain and hypoglycemia. A fixed combination of the long-acting insulin degludec and liraglutide has recently been accepted by the EMA for the management of Type 2 diabetes. The incentive for this combination is to exploit the advantages of each of the drugs while counterbalancing the side effects. Insulin degludec effectively reduces fasting plasma glucose, but carries the risk of hypoglycemia and body weight gain. Liraglutide, on the other hand, exerts glycemic control with a minimal risk of hypoglycemia and, at the same time, reduces appetite and body weight.

Does a GLP-1 receptor agonist change glucose tolerance in patients treated with antipsychotic medications? Design of a randomised, double-blinded, placebo-controlled clinical trial

BACKGROUND

Metabolic disturbances, obesity and life-shortening cardiovascular morbidity are major clinical problems among patients with antipsychotic treatment. Especially two of the most efficacious antipsychotics, clozapine and olanzapine, cause weight gain and metabolic disturbances. Additionally, patients with schizophrenia-spectrum disorders not infrequently consume alcohol. Glucagon-like peptide-1 (GLP-1) has shown to improve glycaemic control and reduce alcohol intake among patients with type 2 diabetes.

OBJECTIVES

To investigate whether the beneficial effects of GLP-1 analogues on glycaemic control and alcohol intake, in patients with type 2 diabetes, can be extended to a population of pre-diabetic psychiatric patients receiving antipsychotic treatment.

METHODS AND ANALYSIS

Trial design, intervention and participants: The study is a 16-week, double-blinded, randomised, parallel-group, placebo-controlled clinical trial, designed to evaluate the effects of the GLP-1 analogue liraglutide on glycaemic control and alcohol intake compared to placebo in patients who are prediabetic, overweight (body mass index ≥27 kg/m(2)), diagnosed with a schizophrenia-spectrum disorder and on stable treatment with either clozapine or olanzapine.

OUTCOMES

The primary endpoint is the change in glucose tolerance from baseline (measured by area under the curve for the plasma glucose excursion following a 4 h 75 g oral glucose tolerance test) to follow-up at week 16. The secondary endpoints include changes of dysglycaemia, body weight, waist circumference, blood pressure, secretion of incretin hormones, insulin sensitivity and β cell function, dual-energy X-ray absorption scan (body composition), lipid profile, liver function and measures of quality of life, daily functioning, severity of the psychiatric disease and alcohol consumption from baseline to follow-up at week 16. Status: Currently recruiting patients.

ETHICS AND DISSEMINATION

Ethical approval has been obtained. Before screening, all patients will be provided oral and written information about the trial. The study will be disseminated by peer-review publications and conference presentations.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT01845259, EudraCT: 2013-000121-31.

The effect of a glucagon-like peptide-1 receptor agonist on glucose tolerance in women with previous gestational diabetes mellitus: protocol for an investigator-initiated, randomised, placebo-controlled, double-blinded, parallel intervention trial

INTRODUCTION

Pregnancy is associated with decreased insulin sensitivity, which is usually overcome by a compensatory increase in insulin secretion. Some pregnant women are not able to increase their insulin secretion sufficiently, and consequently develop gestational diabetes mellitus (GDM). The disease normally disappears after delivery. Nevertheless, women with previous GDM have a high risk of developing type 2 diabetes (T2D) later in life. We aim to investigate the early development of T2D in women with previous GDM and to evaluate whether treatment with the glucagon-like peptide-1 receptor (GLP-1R) agonist, liraglutide, may modify their risk of developing T2D.

METHODS AND ANALYSES

100 women with previous GDM will be randomised to either liraglutide or placebo treatment for 1 year (blinded) with an open-label extension for another 4 years. Additionally, 15 women without previous GDM will constitute a baseline control group. Women will be tested with an oral glucose tolerance test (primary endpoint: area under the curve for plasma glucose) and an isoglycaemic intravenous glucose infusion at baseline, after 1 year and after 5 years. Additional evaluations include a glucagon test, dual-energy X-ray absorptiometry, imaging of the liver (ultrasound elastography and fibroscanning), an ad libitum meal for food intake evaluation and questionnaires related to appetite, quality of life and alcohol consumption habits.

ETHICS AND DISSEMINATION

The protocol has been approved by the Danish Medicines Agency, the Scientific-Ethical Committee of the Capital Region of Denmark, and the Danish Data Protection Agency and will be carried out under the surveillance and guidance of the GCP unit at Copenhagen University Hospital Bispebjerg in compliance with the ICH-GCP guidelines and in accordance with the Helsinki Declaration. Positive, negative and inconclusive results will be published at scientific conferences and as one or more scientific manuscripts in peer-reviewed journals.

REGISTRATIONS

The trial is registered at https://eudract.ema.europa.eu (2012-001371-37) and http://www.clinicaltrials.gov (NCT01795248).

Glucose-dependent insulinotropic polypeptide: a bifunctional glucose-dependent regulator of glucagon and insulin secretion in humans

OBJECTIVE

To evaluate the glucose dependency of glucose-dependent insulinotropic polypeptide (GIP) effects on insulin and glucagon release in 10 healthy male subjects ([means ± SEM] aged 23 ± 1 years, BMI 23 ± 1 kg/m(2), and HbA(1c) 5.5 ± 0.1%).

RESEARCH DESIGN AND METHODS

Saline or physiological doses of GIP were administered intravenously (randomized and double blinded) during 90 min of insulin-induced hypoglycemia, euglycemia, or hyperglycemia.

RESULTS

During hypoglycemia, GIP infusion caused greater glucagon responses during the first 30 min compared with saline (76 ± 17 vs. 28 ± 16 pmol/L per 30 min, P < 0.008), with similar peak levels of glucagon reached after 60 min. During euglycemia, GIP infusion elicited larger glucagon responses (62 ± 18 vs. -11 ± 8 pmol/L per 90 min, P < 0.005). During hyperglycemia, comparable suppression of plasma glucagon (-461 ± 81 vs. -371 ± 50 pmol/L per 90 min, P = 0.26) was observed with GIP and saline infusions. In addition, during hyperglycemia, GIP more than doubled the insulin secretion rate (P < 0.0001).

CONCLUSIONS

In healthy subjects, GIP has no effect on glucagon responses during hyperglycemia while strongly potentiating insulin secretion. In contrast, GIP increases glucagon levels during fasting and hypoglycemic conditions, where it has little or no effect on insulin secretion. Thus, GIP seems to be a physiological bifunctional blood glucose stabilizer with diverging glucose-dependent effects on the two main pancreatic glucoregulatory hormones.

Liraglutide, but not vildagliptin, restores normoglycaemia and insulin content in the animal model of type 2 diabetes, Psammomys obesus

In order to investigate the effect and mechanism of liraglutide and vildagliptin in diabetic Psammomys obesus, we examined proliferation and apoptosis of beta-cells, beta-cell mass (BCM), and pancreatic insulin content after zero, six and fourteen days of treatment compared to control groups. One group of animals was kept on low-energy diet and seven groups were given high-energy diet (HED) that induced diabetes over a four week period. Non-fasting morning blood glucose, body weight, HbA(1C) and pancreatic insulin content were measured and beta cell mass (BCM), proliferation and apoptosis frequencies were determined using stereological point counting. Liraglutide significantly reduced blood glucose and even normalized it in all animals treated for six days and in 11 out of 17 animals treated for fourteen days. HED increased BCM and treatment with liraglutide did not change this. However, compared to the vehicle-treated animals pancreatic insulin content was normalized in animals treated for six and fourteen days with liraglutide. In contrast, vildagliptin, in doses causing full inhibition of plasma DPP-IV activity, neither reduced blood glucose nor altered HED-induced increases in BCM or pancreatic insulin content. These results suggest that liraglutide restores normoglycaemia and improves glycaemic control in P. obesus by increasing their insulin content and improving the function of the beta-cells. In contrast, vildagliptin does not improve glycaemic control in P. obesus nor affect beta-cell insulin content.

Developmental Biology of the Psammomys obesus Pancreas: Cloning and Expression of the Neurogenin-3 Gene

The desert gerbil Psammomys obesus, an established model of type 2 diabetes (T2D), has previously been shown to lack pancreatic and duodenal homeobox gene 1 (Pdx-1) expression. Pdx-1 deficiency leads to pancreas agenesis in both mice and humans. We have therefore further examined the pancreas of P. obesus during embryonic development. Using Pdx-1 antisera raised against evolutionary conserved epitopes, we failed to detect Pdx-1 immunoreactivity at any time points. However, at E14.5, Nkx6.1 immunoreactivity marks the nuclei of all epithelial cells of the ventral and dorsal pancreatic buds and the only endocrine cell types found at this time point are glucagon and PYY. At E18.5 the pancreas is well branched and both glucagon- and ghrelin-positive cells are scattered or found in clusters, whereas insulin-positive cells are not found. At E22.5, the acini of the exocrine pancreas are starting to mature, and amylase and carboxypeptidase A immunoreactivity is found scattered and not in all acini. Ghrelin-, glucagon-, PYY-, gastrin-, somatostatin (SS)-, pancreatic polypeptide (PP)-, and insulin-immunoreactive cells are found scattered or in small groups within or lining the developing ductal epithelium as marked by cytokeratin 19. Using degenerate PCR, the P. obesus Neurogenin-3 (Ngn-3) gene was cloned. Nucleotide and amino acid sequences show high homology with known Ngn-3 sequences. Using specific antiserum, we can observe that Ngn-3-immunoreactive cells are rare at E14.5 but readily detectable at E18.5 and E22.5. In conclusion, despite the lack of detection of Pdx-1, the P. obesus pancreas develops similarly to Muridae species, and the Ngn-3 sequence and expression pattern is highly conserved in P. obesus.