Application of novel peptide (Pp1) improving the half-life of exendin-4 in vivo

Magnetically-driven implantable pump for on-demand bolus infusion of short-acting glucagon-like peptide-1 receptor agonist

For type 2 diabetic patients, short acting glucagon-like peptide-1 receptor agonist (GLP-1 RA) is often prescribed with frequent needled injections. Long-acting GLP-1 RA for less frequent injections do not mimic physiologic secretion of GLP-1. Therefore, an implantable pump is proposed in this work, which can deliver a short-acting GLP-1 RA, exenatide, without needles and batteries. The implanted pump can infuse an accurate amount of exenatide bolus only when a noninvasive magnetic force is applied from outside the body. The pump includes a safety feature of patterned magnets for actuation to prevent accidental infusion possibly caused by a general household magnet. The reservoir for exenatide is made of a flexible biomaterial and thus, a negative pressure build-up in the reservoir can be prevented even after multiple actuations and almost all drug consumption (~ 94%). This allows a reproducible drug dose for a longer period after implantation, hence less frequent replenishment procedures. The pump is also equipped with an intermediate container with two distinct check-valves and thus, the reservoir of exenatide can be further separated and better prevented from infiltration of the bodily fluid surrounding the implanted pump. When tested in Goto-Kakizaki rats, the pump demonstrates the efficacy of exenatide similar to conventional subcutaneous injections. Therefore, the pump can be promising for patient-friendly, optimal delivery of short-acting GLP-1 RA that better follows the physiologic secretion profile of GLP-1.

Comparison of ELISA and HPLC-MS methods for the determination of exenatide in biological and biotechnology-based formulation matrices

The development of biotechnology-based active pharmaceutical ingredients, such as GLP-1 analogs, brought changes in type 2 diabetes treatment options. For better therapeutic efficiency, these active pharmaceutical ingredients require appropriate administration, without the development of adverse effects or toxicity. Therefore, it is required to develop several quantification methods for GLP-1 analogs products, in order to achieve the therapeutic goals, among which ELISA and HPLC arise. These methods are developed, optimized and validated in order to determine GLP-1 analogs, not only in final formulation of the active pharmaceutical ingredient, but also during preclinical and clinical trials assessment. This review highlights the role of ELISA and HPLC methods that have been used during the assessment for GLP-1 analogs, especially for exenatide.

Pleiotropic Effects of GLP-1 and Analogs on Cell Signaling, Metabolism, and Function

The incretin hormone Glucagon-Like Peptide-1 (GLP-1) is best known for its "incretin effect" in restoring glucose homeostasis in diabetics, however, it is now apparent that it has a broader range of physiological effects in the body. Both in vitro and in vivo studies have demonstrated that GLP-1 mimetics alleviate endoplasmic reticulum stress, regulate autophagy, promote metabolic reprogramming, stimulate anti-inflammatory signaling, alter gene expression, and influence neuroprotective pathways. A substantial body of evidence has accumulated with respect to how GLP-1 and its analogs act to restore and maintain normal cellular functions. These findings have prompted several clinical trials which have reported GLP-1 analogs improve cardiac function, restore lung function and reduce mortality in patients with obstructive lung disease, influence blood pressure and lipid storage, and even prevent synaptic loss and neurodegeneration. Mechanistically, GLP-1 elicits its effects via acute elevation in cAMP levels, and subsequent protein kinase(s) activation, pathways well-defined in pancreatic β-cells which stimulate insulin secretion in conjunction with elevated Ca2+ and ATP. More recently, new studies have shed light on additional downstream pathways stimulated by chronic GLP-1 exposure, findings which have direct relevance to our understanding of the potential therapeutic effects of longer lasting analogs recently developed for clinical use. In this review, we provide a comprehensive description of the diverse roles for GLP-1 across multiple tissues, describe downstream pathways stimulated by acute and chronic exposure, and discuss novel pleiotropic applications of GLP-1 mimetics in the treatment of human disease.

A novel GLP-1 analog exhibits potent utility in the treatment of type 2 diabetes with an extended half-life and efficient glucose clearance in vivo

The multiple physiological characterizations of glucagon-like peptide-1 (GLP-1) make it a promising drug candidate for the therapy of type 2 diabetes. However, the half-life of GLP-1 is short in vivo due to degradation by dipeptidyl peptidase-IV (DPP-IV) and renal clearance. Therefore, the stabilization of GLP-1 is critical for its utility in drug development. Based on our previous research, a GLP-1 analog that contained an intra-disulfide bond exhibited a prolonged biological half-life. In this study, we improved upon previous analogs with a novel GLP-1 analog that contained a tryptophan cage-like sequence for an improved binding affinity to the GLP-1 receptor. The binding capacities and the stabilities of GLP715a were investigated, and the physiological functions of the GLP715a were compared to those of the wild-type GLP-1 in animals. The results demonstrated that the new GLP-1 analog (GLP715a) increased its biological half-life to approximately 48h in vivo; GLP715a also exhibited a higher binding affinity to the GLP-1 receptor than the wild-type GLP-1. The increased binding capacity of GLP715a to its receptor resulted in a quick response to glucose administration. The long-acting anti-diabetic property of GLP715a was revealed by its increased glucose tolerance, higher HbA(1c) reduction, more efficient glucose clearance and quicker insulin stimulation upon glucose administration compared to the wild-type GLP-1 in rodents. The improved physiological characterizations of GLP715a make it a possible potent anti-diabetic drug in the treatment of type 2 diabetes mellitus.