Insulin release from isolated cat islets of Langerhans

Assessment of Exenatide Extended-Release for Maintenance of Diabetic Remission in Cats

BACKGROUND

Insulin-treated diabetic cats frequently achieve transient remission. The glucagon-like peptide-1 receptor agonist, exenatide extended-release (exenatide-ER), preserves β cell function in people with type 2 diabetes mellitus (DM).

OBJECTIVES

Investigate the effect of exenatide-ER on the duration of diabetic remission in cats.

ANIMALS

Twenty-two client-owned cats with recent diabetic remissions.

METHODS

Placebo-controlled, single-blinded study. Cats were assigned randomly to receive exenatide-ER (0.13 mg/kg) or saline injection SC, once monthly for 2 years or until DM relapsed. Cats were fed low-carbohydrate diets; weight control was actively supervised. Paired t-tests and Mann-Whitney were used to compare pre- versus post-study characteristics within groups and between group outcomes, respectively.

RESULTS

Treatment groups (placebo, N = 10; exenatide-ER, N = 12) were similar in age, sex, and body weight upon inclusion. Thirteen cats completed the 2-year study without diabetic relapse. Nine cats (placebo, n = 4; exenatide-ER, n = 5) exited prematurely. Three of these exited because of DM relapse (placebo: N = 1, day 212; exenatide-ER: N = 2, days 553 and 558). There was no difference in remission duration between treatments (placebo: 669 [121-721]; exenatide-ER: 662 [28-735] days, p = 0.9). Median body weight decreased in both groups at study exit (placebo: -0.6 kg [-1.3 to +0.3], p = 0.03; exenatide-ER: -0.2 kg [-1.2 to +0.5], p = 0.02). Hemoglobin A1c remained unchanged on exenatide-ER (-0.05% [-6.9 to +2.1]) but increased on placebo (+2.3% [-1.7 to +4.4]; p = 0.03).

CONCLUSIONS AND CLINICAL IMPORTANCE

Exenatide-ER contributed to the maintenance of glycemic control as reflected by hemoglobin A1c but did not affect remission duration. Management might have contributed to the extended remission duration.

Isolation of feline islets of Langerhans by selective osmotic shock produces glucose responsive islets

Introduction

Pancreatic islet isolation is essential for studying islet physiology, pathology, and transplantation, and feline islets could be an important model for human type II diabetes mellitus (T2D). Traditional isolation methods utilizing collagenases inflict damage and, in cats, may contribute to the difficulty in generating functional islets, as demonstrated by glucose-stimulated insulin secretion (GSIS). GLUT2 expression in β cells may allow for adaptation to hyperosmolar glucose solutions while exocrine tissue is selectively disrupted.

Methods

Here we developed a protocol for selective osmotic shock (SOS) for feline islet isolation and evaluated the effect of different hyperosmolar glucose concentrations (300 mmol/L and 600 mmol/L) and incubation times (20 min and 40 min) on purity, morphology, yield, and GSIS.

Results

Across protocol treatments, islet yield was moderate and morphology excellent. The treatment of 600 mmol/L glucose solution with 20 min incubation resulted in the highest stimulation index by GSIS.

Discussion

Glucose responsiveness was demonstrated, permitting future in vitro studies. This research opens avenues for understanding feline islet function and transplantation possibilities and enables an additional islet model for T2D.