Vascular dementia with no cure, challenging the world's first research

Professor Ko Sung-ho of the Department of Neurology at Hanyang University Guri Hospital / Provided by Hanyang University Guri Hospital

What is the difference between vascular dementia and Alzheimer's disease?

Vascular dementia is a condition caused by impaired blood circulation to the brain or a lack of oxygen and nutrients, leading to brain damage. It particularly affects cognitive functions responsible for memory and judgment. Symptoms may develop gradually or suddenly. In contrast, Alzheimer's disease involves the accumulation of amyloid beta proteins or tau proteins in the brain over a long period. However, it is not easy to distinguish between the two based solely on symptoms. Especially among vascular dementias, subcortical dementia is very similar to Alzheimer's disease. The subcortical area is close to the surface of the brain and is closely related to cognitive functions. If blood supply to this area is disrupted, it can lead to vascular dementia very gradually. In such cases, the clinical symptoms are very similar to those of Alzheimer's disease.

- How is vascular dementia diagnosed?

If it is difficult to distinguish, perform a test to determine whether it is Alzheimer's disease and assess for vascular dementia. Among outpatient cases, there was a patient who experienced a stroke a year ago and had a decline in memory. While it clearly meets the criteria for dementia, it was not immediately clear whether it was Alzheimer's disease or vascular dementia. Therefore, an amyloid PET/CT scan was performed, which showed that it was not Alzheimer's disease. This revealed that it was vascular dementia.

Stroke is a condition where the brain's blood vessels become blocked or burst, causing brain damage. If the area responsible for specific memories is affected by a stroke, it can be difficult to distinguish from vascular dementia symptoms. If, six months after a stroke, normal memory function has not been restored and there is a clear decline in cognitive abilities such as difficulty recognizing time, place, or people, it is diagnosed as vascular dementia.

Ischemic stroke caused by blocked cerebral blood vessels also shares many symptoms with vascular dementia. Even if vascular dementia appears, if language impairment or paralysis of the arms and legs occurs due to the stroke, these symptoms can easily lead to overlooking the signs of vascular dementia. Ultimately, if cognitive function does not recover within six months after the stroke, vascular dementia is suspected.

–It seems difficult to diagnose. How is the treatment going?

Currently, there is no cure at all. If symptoms appear similar to those of a stroke, antiplatelet agents, which are stroke treatments, can be used, but there are no medications specifically for treating vascular dementia. In the past, Alzheimer's disease treatments such as cholinesterase inhibitors were sometimes prescribed as treatments for vascular dementia. However, large-scale Phase 3 clinical trials to verify whether this method could effectively treat vascular dementia failed to demonstrate efficacy. As a result, in 2019, the Ministry of Food and Drug Safety issued guidelines advising against prescribing these drugs for vascular dementia. Recently developed Alzheimer's treatments, such as donanemab and lecanemab (whose active ingredient is lecanemab), also have side effects including brain edema and cerebral hemorrhage, making it impossible to prescribe them if there is even a slight possibility of vascular dementia. This is because such treatments could potentially worsen the condition.

How many patients have vascular dementia?

Korea has a low level of interest in vascular dementia, yet its incidence rate is high. Since there are no characteristic patterns unique to vascular dementia, diagnosis requires estimation, but it is known that over 10% of dementia patients worldwide suffer from vascular dementia. In Korea, this ratio is estimated to be at least 15%, potentially reaching up to 30%. Considering mixed dementia, which involves multiple types of dementia occurring together, the ratio is likely even higher. The reason why more patients with vascular dementia appear in Korea has not been clearly identified, but factors such as racial characteristics, a diet that is salty and spicy, and insufficient physical activity are suspected causes. The fact that there are no treatments for diseases that are particularly prominent in Korea is a serious issue.

They are developing a new drug for vascular dementia.

It is still in the preclinical stage, so it is difficult to speak specifically. However, the focus is on nerve regeneration. As people age, the regenerative function of nerve cells or cells supporting nerve cells becomes significantly weakened. When these cells are damaged, the nervous system also cannot regenerate, leading to a broken nerve cell network. If these symptoms accumulate, they can develop into vascular dementia. Therefore, by reducing neuroinflammation and promoting regeneration, it is hypothesized that vascular dementia can also be treated, and new drugs are being developed based on this hypothesis. Not only new drugs but also medical devices such as ultrasound therapy are being utilized to enhance treatment effects. The project receives government support for five years, and the goal in the fifth year is to proceed to clinical trials involving humans.

How to prevent vascular dementia in daily life.

The preventive measures themselves are not very different from those for Alzheimer's disease or stroke. This is because vascular dementia often occurs alongside stroke or cerebral infarction. Risk factors such as hypertension, hyperlipidemia, diabetes, obesity, as well as alcohol and smoking, must be actively managed. Additionally, maintaining healthy sleep habits and a diet focused on vegetables, such as the Mediterranean or Korean diet, is recommended.

The reason for changing the research direction to vascular dementia.

Alzheimer's disease has already received a lot of attention. To exaggerate a bit, a new paper comes out every time I wake up. Since last year, new treatments like Leqembi and Donanemab have also appeared, and I have developed a blood-based biomarker (biomarker) for diagnosing Alzheimer's disease through blood tests. However, vascular dementia has not received attention either in Korea or worldwide. There are not many studies on it. I think this is probably because it often overlaps with other brain diseases, leading to many clinical trials focused solely on vascular dementia to fail.

However, we cannot give up on treatment for patients with vascular dementia. Feeling sorry for this situation, I became interested in vascular dementia. On the other hand, although it is not easy for Korea to surpass advanced medical countries like the United States in the field of Alzheimer's disease, vascular dementia also motivated me with a sense of challenge and reward, as I could potentially conduct the world's first research. I hope that research on vascular dementia will yield results and help patients.