D i a b e t e s

by: Jeduthun Harris (Medical Student)

Type 1 characteristically affects young children. Its origin lies in an irregular immune response that causes white blood cells to attack the Islets of Langerhans in the pancreas. The Islets of Langerhans are the cells in the pancreas (an organ) that synthesize and secrete insulin. Insulin is the hormone that lowers blood glucose levels when it is elevated, e.g., just after a meal. The white blood cells destroys pathogens (bacteria, viruses, material foreign to the body) when they enter the body. Due to a genetic defect, the Islets of Langerhans cells fail to synthesize a protein that coats the outside surface of the cell. This protein is a “marker” that labels these cells as somatic (belonging to the body).  Therefore, since these cells lack this protein on their surface, the white blood cells “recognize” these cells as pathogenic (foreign) and destroy them. This ultimately leads to a deficiency in insulin. Hence, when blood glucose levels are elevated, the lack of insulin causes blood sugar levels to remain elevated. 

 Type 2 diabetes mainly affects adults. As cells age, some of them tend to develop resistance to the hormone insulin. Insulin mediates its response on cells so that they absorb glucose from the blood, lowering the blood glucose level. When these cells become unresponsive to insulin, they do not absorb glucose from the blood. The Islets of Langerhans responds to this resistance by secreting more insulin. This usually overcomes the resistance. Because the Islets of Langerhans cells are secreting excess insulin, being “overworked” in a sense, they develop impaired function.  Hence,  a combination of insulin resistance and impaired Beta cell (Islets of Langerhans) function, leads to elevated blood sugar levels in Type 2 Diabetes.