Pancreatic beta cells make insulin, a hormone that helps control blood sugar levels in the body. Type 2 diabetes (T2D) is a metabolic disease in which these beta cells do not work properly and cannot release enough insulin to keep blood sugar at a healthy level. To release insulin, beta cells need energy. This energy is produced by structures inside the cell called mitochondria.
Mitochondria act as the cell’s “power plants”. They produce energy through a process called electron transport, which takes place using special proteins in the inner membrane of the mitochondria. In people with T2D, beta cells are exposed to long-term stress. Under these conditions, electrons can escape from the transport system and react with oxygen, forming harmful molecules and causing oxidative stress.
Oxidative stress can damage important parts of the beta cell. It can harm proteins involved in energy production, making mitochondria less efficient. As a result, the cell produces less energy and struggles to release enough insulin. Oxidative stress can also damage mitochondrial DNA, which can trigger inflammation and further worsen mitochondrial function.
Healthy cells have systems that remove damaged mitochondria to maintain the health of mitochondrial networks. However, in T2D, ongoing oxidative stress causes mitochondria to break apart into smaller fragments. This fragmentation disrupts energy production even more and reduces the beta cell’s ability to release insulin. Studies have shown that beta cells from people with T2D often contain fragmented mitochondria, highlighting how important healthy mitochondria are for normal insulin release.
In summary, long-term stress in the mitochondria of beta cells leads to excessive oxidative stress, inflammation, and damage to mitochondrial structure. This reduces energy production and weakens insulin secretion. Researchers are now studying ways to protect or improve mitochondrial function, and early clinical studies suggest this approach may lead to new treatments for type 2 diabetes.
About the author
Hing Chuk Lau
Hing Chuk Lau is a graduate student at the University of Toronto researching the role of oxidative stress in diabetes, with the goal of uncovering novel treatment strategies for diabetes.
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