Dysregulation of Metabolic Peptides in the Gut-Brain Axis Promotes Hyperinsulinemia, Obesity, and Neurodegeneration.

Metabolic peptides can influence metabolic processes and contribute to both inflammatory and/or anti-inflammatory responses. Studies have shown that there are thousands of metabolic peptides, made up of short chains of amino acids, that the human body produces. These peptides are crucial for regulating many different processes like metabolism and cell signaling, as they bind to receptors on various cells. This review will cover the role of three specific metabolic peptides and their roles in hyperinsulinemia, diabetes, inflammation, and neurodegeneration, as well as their roles in type 3 diabetes and dementia. The metabolic peptides glucagon-like peptide 1 (GLP-1), gastric inhibitor polypeptide (GIP), and pancreatic peptide (PP) will be discussed, as dysregulation within their processes can lead to the development of various inflammatory and neurodegenerative diseases. Research has been able to closely investigate the connections between these metabolic peptides and their links to the gut-brain axis, highlighting changes made in the gut that can lead to dysfunction in processes in the brain, as well as changes made in the brain that can lead to dysregulation in the gut. The role of metabolic peptides in the development and potentially reversal of diseases such as obesity, hyperinsulinemia, and type 2 diabetes will also be discussed. Furthermore, we review the potential links between these conditions and neuroinflammation and the development of neurodegenerative diseases like dementia, specifically Parkinson's disease and Alzheimer's disease.