Oxidative Stress and Chemo Brain

Summary 

Chemotherapy is one of the treatment options for many different types of cancers including MDS. While often effective at killing cancer cells, it can come with some challenging side effects, including cognitive difficulties commonly known as "chemo brain." This condition can result in memory issues and difficulties in concentration. Researchers conducted a study in 2021 that showed chemo brain is linked to a harmful process called oxidative stress. Oxidative stress happens when there's an imbalance between the production of free radicals which are often a byproduct of chemotherapy and the body's ability to counteract their negative effects with antioxidants. This review explores how chemotherapy drugs can contribute to oxidative stress and subsequent cognitive impairments, examining studies conducted on both human and animal models. It also looks into potential treatments that could prevent or mitigate these effects. 

Oxidative Stress and Chemo Brain 

When someone undergoes chemotherapy, they are often focused on the primary goal: beating cancer. However, these powerful drugs don't just target cancer cells; they can also affect other parts of the body, including the brain. Patients may notice changes in their cognitive function, experiencing difficulties with memory, attention, and other mental tasks. This phenomenon, sometimes referred to as "chemo brain," can be distressing and impact quality of life. 

Research has found that certain chemotherapy drugs can cause oxidative stress, a condition where harmful molecules called free radicals damage cells. The brain is particularly vulnerable to oxidative stress because of its high oxygen consumption and rich fat content, which can be easily damaged by high amounts of these free radical molecules. 

In reviewing scientific studies, researchers have observed that chemotherapy drugs such as doxorubicin and cisplatin can lead to an increase in oxidative stress markers in the brain. This has been demonstrated not only in lab-grown brain cells but also in live animal models. For example, mice given high doses of doxorubicin showed increased protein and fat damage in the brain as a result of oxidative stress.  

Oxidative stress is also linked to inflammation in the brain, which can contribute to cognitive dysfunction. Inflammatory substances increase in the brain after treatment with these drugs, and pathways that signal stress responses become more active. Furthermore, oxidative stress can lead to damage to DNA and RNA within brain cells, affecting their function and communication. 

Interestingly, some studies indicate that cancer itself may prompt oxidative stress and cognitive impairments even before any treatment begins. Researchers found increased oxidative damage in the brains of mice with tumors, suggesting that the disease process might also contribute to these issues. 

Antioxidant Treatment for Brain Protection

Recognizing the potential role of oxidative stress in cognitive side effects, scientists are exploring treatments to protect the brain. Antioxidants, substances that can neutralize harmful free radicals, have shown promise in reducing oxidative stress in animal models. For instance, the antioxidant N-acetylcysteine (NAC) was found to protect brain cells from the effects of cisplatin. Other antioxidant substances, like MESNA, have improved markers of oxidative stress in blood and brain tissue. Something to note is that antioxidants do interfere with the effects of chemotherapy on the body during administration because antioxidants protect cells from damage. Patients should consult with their doctor about the potential use of antioxidant therapy after chemotherapy and not during to help ensure chemotherapy is effective during administration at killing cancer cells. 

Conclusion

The cognitive side effects of chemotherapy are an important consideration in cancer treatment. The evidence supports a link between these side effects and oxidative stress induced by chemotherapy drugs. As researchers continue to unravel the complex interactions between chemotherapy, the brain, and oxidative stress, there's hope for developing interventions that could safeguard cognitive function during cancer treatment. Antioxidants such as N-acetylcysteine show potential in protecting the brain and improving cognitive outcomes. Understanding the mechanisms of "chemo brain" is vital for creating comprehensive cancer care strategies that address both the physical and cognitive challenges patients face.