Beta cells are specialised cells located in the islets of Langerhans in the pancreas that produce and secrete insulin, a hormone crucial for regulating blood glucose levels. Their dysfunction or destruction is central to the pathophysiology of diabetes mellitus, leading to hyperglycaemia and associated complications. For instance, in Type 1 diabetes, autoimmune destruction of beta cells results in insulin deficiency, necessitating lifelong insulin therapy to manage blood sugar levels.