Developing non-invasive methods to measure muscle force, relaxation time and mitochondrial dysfunction in sarcopenia

Principal Investigator - Dr Karen Suetterlin, NIHR Clinical Lecturer in Neurophysiology, Newcastle University

‌Sarcopenia is the accelerated loss of muscle mass and function due to ageing. It leads to falls and reduced quality of life. Sarcopenia is very common affecting up to 10% of people over the age of 50.  It can be diagnosed by a simple and inexpensive grip force test. However, this doesn’t tell us about the cause of sarcopenia.

One possible cause for sarcopenia is a problem with the mitochondria. Most of the energy in cells comes from mitochondria which are highly specialised energy powerhouses. Muscles need a lot of energy and so if there are problems with the mitochondria this can lead to sarcopenia. This project aimed to develop a simple, non-invasive test (including a measure of grip strength plus muscle relaxation time and muscle oxygen levels) that can be used to reliably diagnose and monitor sarcopenia and mitochondrial dysfunction. 

The study team purchased and trained in the use of a painless, non-invasive technique that uses near-infra-red spectroscopy to measure muscle oxygen levels. They developed and refined a new digital dynamometer, adapted to have a very high sampling frequency so that as well as measuring contraction force it can detect small changes in relaxation time (an energy intense process).

A total of 18 healthy volunteers have been recruited and recruitment is ongoing of genetically confirmed mitochondrial disease patients (obtained by access to the Newcastle Mitochondrial Cohort). Recruiting people with known mitochondrial dysfunction will allow the study team to validate these tests’ ability to reliably detect mitochondrial dysfunction.

This project facilitated the training of early career researchers in the development of an ethics application, interdisciplinary collaboration and the technique of neuromuscular ultrasound.  This learning was shared at an interactive workshop, led by Dr Suetterlin, at the International Sarcopenia Translational Research Conference in October 2023.  Initial findings from the project have been presented at international conferences with publications set to follow.

Collaborating Institutions - Newcastle University, National Institutes of Health Clinical Center, USA