The ECG or electrocardiogram is a familiar device in many doctors’ clinics. For individuals at risk of developing heart conditions, the ECG has been the go-to diagnostic tool for decades.
However, even for those with brain trauma, there is no equivalent diagnostic tool as the ECG.
Now, researchers from Harvard University have harnessed the body’s immune cells to literally spotlight brain injuries. They developed tiny patches that can be injected into the bloodstream to latch on to immune cells called macrophages. These patrolling cells then carry the patches straight to injury sites in the brain.
The patches light up when MRI scans are done, allowing clear view of damaged areas that would otherwise be missed. It is akin to giving the immune system its own GPS system to locate threats.
The tool, dubbed ‘M-GLAM’, was 30-70 per cent as sensitive as an ECG in identifying health conditions, and 70-100 per cent in distinguishing healthy individuals, notes Dr Lily Li Wen-Wang, a scientist at biotechnology firm Landmark Bio and author of the research paper.
Better than convention
While M-GLAMs are not as sensitive as ECGs are for heart conditions, they could still be useful in diagnosing mild traumatic brain injuries, notes Dr Wang. An imaging method, even with a modest performance, could significantly enhance the accuracy of diagnosing such injuries. This is because “conventional imaging techniques often fall short, leading to as many as 60 per cent of mild traumatic brain injury [TBI] cases being missed in emergency departments,” she adds.
Mild traumatic brain injury can occur when someone experiences a bump or jolt to the head, commonly known as a concussion. This can lead to brief unconsciousness, confusion, memory loss, headaches and other symptoms. If the symptoms persist, they can cause post-concussion syndrome.
With the introduction of M-GLAMs, there is potential to target the surrounding tissues of the brain barrier, allowing them to enter the central nervous system precisely where conventional diagnostics couldn’t penetrate to detect the injury site.
“In our study, we demonstrated the effective accumulation of M-GLAMs in the target tissues while minimising signals in off-target areas,” adds Dr Wang.
Future applications
The study was conducted in a small-scale pig model where M-GLAMs provided clearer MRI signals at significantly lower doses.
In the future, it could be interesting to explore other immune cell populations for TBI diagnosis depending on the duration between injury and diagnosis.
“For example, neutrophils, another type of immune cell, are known to exhibit greater movement into brain tissue as early as the 0-1-day window post-TBI. This suggests that neutrophils might be a better carrier for the contrast agent during that time window,” adds Dr Vineeth Chandran Suja, post-doctoral researcher at Harvard University.
Considering these insights, M-GLAMs stand as a beacon of hope for other brain disorders marked by inflammation in the future. Thus, for effective use of immune cells, it would be crucial to understand the specific mechanisms of how these cells can penetrate the injury site.
“In clinical practice, integrating M-GLAM-based imaging with existing diagnostic approaches, such as physical examinations and individual history, may offer a comprehensive pathway for diagnosis and treatment,” adds Dr Wang.
