researchers of the University of Barcelona have developed a new tool to assess the presence and severity of muscle failure that manifests sarcopenia, which occurs, above all, in older people. A key feature of this degenerative disease is the deterioration in the amount and muscle qualitywhich worsens the quality of life and is associated with cardiorespiratory diseases and an increased risk and prolongation of hospital admission.
Muscle quality is an important factor in other muscle diseases besides sarcopenia. Thus, for researchers, musculoskeletal ultrasound could also have application in other disorders or even in the rehabilitation of athletessince it will allow to delve into the knowledge of the muscle qualitythe variations of this in different immunological, degenerative, metabolic diseases and treatment monitoring. “It is the starting point in an area in which there is no similar test, so we believe that it is a tool that will spread in this and other diseases,” he points out. Ingrid Mollerresearcher at the UB and the Poal Institute of Rheumatology and first signatory of the article.
Now a new study, published in the journal RMD Openprovides a scoring system for the muscle quality based on musculoskeletal ultrasound scans, which has been validated with anatomical and histological samples from patients. According to the researchers, these results could be useful “not only for diagnostic purposes, but also for monitoring patients in clinical practice and in clinical trials.”
Researchers from the Human Anatomy and Embryology Unit and the Histology Unit of the Department of Pathology and Experimental Therapeutics of the Faculty of Medicine and Health Sciences (Campus Bellvitge) of the UB have participated in the work. Experts from the Puigvert Foundation, the University of Genoa, the University of Oslo and the University of Copenhagen have also taken part in the study.
falls and weakness
Currently, a wide variety of tests and tools are available for the characterization of the disease in practice and in research. «In most cases the diagnosis and evolution is measured by functional tests or patient surveys on aspects such as falls, feeling weak, slow walking, trouble getting up from a chair, or weight losswhich allow us to know the state of the patient”, explains Ingrid Moller.
In this context, imaging techniques have a critical role in the objective evaluation of sarcopenic patients. However, most, such as absorptiometry with dual-energy x-rays (DXA), magnetic resonance imaging (MRI), or computed tomography (CT), focus on muscle quantity. «These techniques show the amount of muscle, but the muscle quality —which is a relatively new term— is more important, since the amount is highly variable due to different factors such as age or height”, the researcher points out.
Currently there is no universal consensus on the appropriate assessment methods of muscle quality in routine clinical practice. In this situation, the researchers propose the use of musculoskeletal ultrasound, as it is a technique able to show muscle texture and changes on micro and macroscopic aspects of the architecture and muscular composition that causes sarcopenia. Furthermore, unlike other imaging techniques, it is a test of low cost, portable and harmless, which does not emit ionizing radiation.
To confirm the diagnostic validity of this new tool, the study evaluated a muscle from the lower extremity (rectus femoris) and another from the upper extremity (biceps brachii) from ten cadavers of blood donors. between 68 and 91 years. To do this, two investigators qualitatively assessed and scored the severity of muscle degeneration from ultrasound images and then compared the results with the anatomical and histological evaluation of the cadavers.
The evaluation was carried out blindly with respect to the other evaluator and half an hour later, each of the investigators repeated it. In addition, evaluation by an experienced histologist under the same methodological conditions was also added. According to the researchers, this methodology is one of the “strengths of the study, as it allows direct comparison between imaging and clinical measurements of muscle quality.”
The next challenge for the researchers is to verify the scoring system in patients and test the added value of the tool in the long-term follow-up of patients with sarcopenia, as well as its application in related clinical trials. In this sense, as the researcher explains, the team from the University of Copenhagen who has participated in this work, will apply the new tool in a cohort of patients to see how it works in prognostic value. “We believe that it works very well on diagnoses, but both in this case and in its prognostic value, it must be confirmed in longitudinal studies with patients”, explains Ingrid Möller.