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The pancreas is an exocrine gland that produces two key hormones involved in the regulation of blood sugar: Insulin and Glucagon. Beta cells are distinctive cells within the pancreas that are responsible for the production of insulin. They’re one of a minimum of 5 different types of islet cells, located within the section of the pancreas called the islets of Langerhans, that secrete hormones directly into the blood.
The Role of Beta Cells
The main role of beta cells is to provide and secrete insulin into the bloodstream when needed. When blood sugar levels begin to rise, such as when you are eating, beta cells quickly respond by secreting insulin into the bloodstream to take up the glucose being produced and store it in fat cells. Insulin should be considered primarily a fat storage hormone clearing the blood stream of excessive glucose and converting it to fat. Diabetes is a disease of insulin resistance in which these beta cells are either attacked or destroyed by the immune system (type 1 diabetes), or become resistant to the effects of insulin (type 2 diabetes).
The Role of Amylin and C-peptide
As a byproduct of insulin production, beta cells also produce two other products: Amylin and C-peptide.
Type 1 Diabetes
In Type 1 diabetes, beta cells die from an immune attack. Immune cells which normally fight harmful bacteria and viruses mistakenly destroy beta cells in the pancreas. The cause and avenue of destruction isn’t clear; however, the results of a study published in early 2011 show that these beta cells become stressed at the earliest stages of the illness.
In studies using mice, cells respond to this stress by triggering a death pathway leading to the loss of beta-cell function and ultimately loss of cell mass. As a result, stress on beta cells resulting from an immune attack may be responsible for type 1 diabetes. Type 1 diabetes has strong genetic links and mostly occurs in children.
Type 2 Diabetes
In Type 2 diabetes, the body loses sensitivity to insulin over time until it becomes immune to the effects of insulin. Consequently, it tries to compensate by producing more insulin. Research has shown that elevated blood sugar levels (chronic hyperglycemia) over a protracted amount of time will result in beta cell burn out or cell turnover. Although the exact cause is unclear, certain factors could contribute significantly such as chronic low-grade inflammation, the accumulation of high levels of glucose (glucotoxicity), or simply the effects of lipoproteins, leptin, and cytokines which play a role in glucose regulation.
Insulin Resistance in Type 2 Diabetes
The beta cells of the pancreas work as extremely connected clusters called islets, and their response to rising blood sugar levels are coordinated by little groups of “leader cells”, which initiate their coordination once blood sugar levels peak in the blood. It is possible that the leader cells are more metabolically active and more glucose-sensitive than the rest making them the primary target for insulin resistance.
Insulin resistance in type 2 diabetes starts out, as described above, with decreasing peripheral sensitivity to insulin leading to an overproduction of insulin by the beta cells. This peripheral insulin resistance is primarily triggered by chronic over storage of fat as a result of excessive carbohydrate consumption and inadequate glycogen depletion.
Due to the increasing levels of insulin resistance, patients continue to suffer from elevated blood glucose levels with sweeping consequences. After a period of time, internal insulin production decreases, likely from excessive fat accumulation in the pancreas and localized changes in blood flow, resulting in the patient needing an external source of insulin.
New Drug To Stimulate Growth of Beta Cells
Researchers from Mount Sinai Hospital have discovered a unique combination of medication that induces the growth of beta cells. The lead author of the study Andrew Stewart, MD had this to say:
“We have discovered a drug combination that makes beta cells regenerate at rates that are suitable for treatment. The next big hurdle is figuring out how to deliver them directly to the pancreas.”
If beta cells can be stimulated to regenerate, then insulin resistance will no longer be an insurmountable obstacle for diabetics, and it will provide the much-needed breakthrough in the treatment of diabetes.
1. Mayo Clinic: Type 2 diabetes. Retrieved from https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/symptoms-causes/syc-20351193
2. Mayo Clinic: Type 1 diabetes. Retrieved from https://www.mayoclinic.org/diseases-conditions/type-1-diabetes-in-children/symptoms-causes/syc-20355306
3. NCBI (2008): Insulin signaling in the pancreatic beta-cell. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/18481923
4. Science Daily (2018): Diabetes: New drug cocktail increases human beta cell proliferation at rapid rates. Retrieved from https://www.sciencedaily.com/releases/2018/12/181220111759.htm