Scientists developed the first-ever microscope that examines the muscles of the body in live action. This may pave the way for studying potentially-debilitating neuromuscular diseases.
Researchers from the Stanford University developed the machine to visualize and measure force-generating contractions of individual motor units. In the past, when scientists study muscles, they slice a tissue sample and examine it under a microscope. This means that they are not studying living tissue. With the new invention, scientists can see living muscles performing various actions.
There are millions of people around the globe diagnosed with severe neuromuscular diseases which, when diagnosed late, may lead to debilitating effects on the body. Immediate initiation of therapeutics may not be given at the right time.
This new microscope visualizes living muscle tissues in action. It will eventually shed light on the study of how certain diseases concerning muscles start and progress.
"When it comes to muscle microstructure and dynamics, we have not been able to visualize normal muscle, and we don't know how it changes with disease," Scott Delp, a professor of bioengineering at Stanford University and co-author of the study said.
He said that the new microscope will examine how muscles change with strokes and neuromuscular diseases such as amyotrophic lateral sclerosis (ALS) and muscular dystrophy (MD).
"We can immediately use it in humans; it's very low risk, and it gives us a new way to examine muscle microstructure and dynamics," he added.
In the study published in the journal Neuron, muscle contractions usually rely on the power of sarcomeres. Sarcomeres are the basic unit that makes muscles work and contract when triggered, causing muscle movement.
The length of a sarcomere influences its efficacy in pulling muscle fibers to move. When it becomes too short, it may lead to muscle weakness. Scientists pointed that one reason behind neuromuscular diseases is that sarcomeres become too short to produce potent muscle force.
The researchers developed the microscope based on a technology that has been known for around two decades. The microscope contains small components with an ultrafast laser light source. It connects to an optical needle inserted into a patient's muscle.
The wearable microscope straps to the human body wherein it will show the contractile dynamics of single motor units.
"We see this as a very useful companion diagnostic to track disease progression and, in the future, help personalize medicine by gauging how a person responds to a drug," co-author Gabriel Sanchez said.
Researchers visualized sarcomere displacements by electrically stimulating twitches through the microendoscope.
"Control experiments verified that these evoked twitches involved neuromuscular transmission and faithfully reported muscle force generation," the authors reported in their study.
"In post-stroke patients with spasticity of the biceps brachii, we found involuntary microscopic contractions and sarcomere length abnormalities," they added. "The wearable microscope facilitates exploration of many basic and disease-related neuromuscular phenomena never visualized before in live humans."
