New Potential Targets of Glucagon-Like Peptide 1 Receptor Agonists in Pancreatic β-Cells and Hepatocytes

Potential Role of Phytochemicals as Glucagon-like Peptide 1 Receptor (GLP-1R) Agonists in the Treatment of Diabetes Mellitus

Currently, there is no known cure for diabetes. Different pharmaceutical therapies have been approved for the management of type 2 diabetes mellitus (T2DM), some are in clinical trials and they have been classified according to their route or mechanism of action. Insulin types, sulfonylureas, biguanides, alpha-glucosidase inhibitors, thiazolidinediones, meglitinides, sodium-glucose cotransporter type 2 inhibitors, and incretin-dependent therapies (glucagon-like peptide-1 receptor agonists: GLP-1R, and dipeptidyl peptidase 4 inhibitors: DPP-4). Although some of the currently available drugs are effective in the management of T2DM, the side effects resulting from prolonged use of these drugs remain a serious challenge. GLP-1R agonists are currently the preferred medications to include when oral metformin alone is insufficient to manage T2DM. Medicinal plants now play prominent roles in the management of various diseases globally because they are readily available and affordable as well as having limited and transient side effects. Recently, studies have reported the ability of phytochemicals to activate glucagon-like peptide-1 receptor (GLP-1R), acting as an agonist just like the GLP-1R agonist with beneficial effects in the management of T2DM. Consequently, we propose that careful exploration of phytochemicals for the development of novel therapeutic candidates as GLP-1R agonists will be a welcome breakthrough in the management of T2DM and the co-morbidities associated with T2DM.

Venom Peptides, Polyphenols and Alkaloids: Are They the Next Antidiabetics That Will Preserve β-Cell Mass and Function in Type 2 Diabetes?

Improvement of insulin secretion by pancreatic β-cells and preservation of their mass are the current challenges that future antidiabetic drugs should meet for achieving efficient and long-term glycemic control in patients with type 2 diabetes (T2D). The successful development of glucagon-like peptide 1 (GLP-1) analogues, derived from the saliva of a lizard from the Helodermatidae family, has provided the proof of concept that antidiabetic drugs directly targeting pancreatic β-cells can emerge from venomous animals. The literature reporting on the antidiabetic effects of medicinal plants suggests that they contain some promising active substances such as polyphenols and alkaloids, which could be active as insulin secretagogues and β-cell protectors. In this review, we discuss the potential of several polyphenols, alkaloids and venom peptides from snake, frogs, scorpions and cone snails. These molecules could contribute to the development of new efficient antidiabetic medicines targeting β-cells, which would tackle the progression of the disease.

Diabetes, Incretin Therapy and Thoracic Aortic Aneurysm - What Does the Evidence Show?

Epidemiological evidence supports a reduced prevalence of Thoracic Aortic Aneurysm (TAA) and Abdominal Aortic Aneurysm (AAA) in patients with Diabetes (DM). The mechanisms underlying this negative association are unknown. Some studies support that hyperglycemia has effects on the Extracellular Matrix (ECM), resulting in collagen cross-links and altered proteolytic activity, which ultimately counteracts aneurysm formation. However, recent experimental research indicates that incretin- based anti-diabetic therapy and Glucagon-Like Peptide-1 (GLP-1) may reduce the formation of TAA. GLP-1 is a peptide hormone, released from intestinal L-cells in response to hormonal, neural and nutrient stimuli. In addition to potentiation of meal-stimulated insulin secretion, GLP-1 signaling exerts numerous pleiotropic effects on various tissues, including protective effects on the myocardium and vascular endothelium. Recent studies also report protective effects of GLP-1 based therapy on the formation of aneurysms in animal models and direct effects of GLP-1 signaling on the molecular mechanisms suggested to influence TAA formation, including inflammation, proteolytic activity and collagen composition. In this narrative review, we present the available evidence for effects of GLP-1 on experimental aneurysm development and discuss the potential role of GLP-1 in aneurysm formation based on available data from pre-clinical and clinical studies.