Luke Aldrich

The presentation aims to give an overview of how a liquid chromatography and mass spectrometry system (LCMS-8045 and Nexera X2, Shimadzu Corporation Europa GmbH, Milton Keynes, UK) has been successfully integrated into the biochemistry laboratory at the Carnegie School of Sport at Leeds Beckett University. It also provides an outline of the main concepts and goals of the overarching research project. The LCMS mass spectrometry systems have become an increasingly popular analytical tool in sports and nutritional science because of their sensitivity and specificity in identifying and quantifying compounds in complex biological matrices. Specifically, it can detect and quantify small molecules such as hormones, and several metabolites, making it a valuable tool in the analysis of sports supplements and nutritional interventions. Their use has also become widespread in doping control and forensic investigations in sports. With its capability to analyse a wide range of substances, such as nutrients, proteins, and drugs, the procurement of this equipment has enabled staff and PhD students at the Carnegie School of Sport at Leeds Beckett University to conduct analyses that support ongoing research and facilitate future aspirations. As the technology continues to advance, LCMS mass spectrometry is expected to play an even greater role in advancing our understanding of the effects of nutrition and exercise on human physiology. Furthermore, the presentation will provide a summary of two optimised methods for amino acid and steroid analyses and discuss the challenges encountered while implementing these methods. It will also provide a detailed description of the essential amino acid method, including the presentation of samples and standards, along with key findings of the completed projects. Through the optimisation of the analytical method for measuring amino acid concentrations, we were able to achieve rapid and precise quantification of 18 proteinogenic amino acids in plasma samples collected from older adults involved in research projects focusing on age-related sarcopenia. The samples were first filtered and labelled with a known quantity of standards to compensate for matrix effects and ensure accurate quantification. Chromatographic separation was performed using a specific column, and mass spectrometric detection was performed using an LCMS-8045 triple quadrupole instrument. A gradient elution was used, and the mobile phases were specified. Quality control samples were prepared to measure recovery and ensure the correct application of the method. Samples and standards were injected using an autosampler. In summary, the integration of LCMS technology in the Carnegie School of Sport has led to notable advancements in research quality and capacity. The instrument’s selection has enabled the acquisition of highly sensitive and intricate data. Our analysis of plasma amino acid levels has yielded promising findings, suggesting a possible association between decreased plasma amino acid concentrations and decreased muscle function in older adults. The implementation of this technology has the potential to foster the development of novel insights in our field.

We appreciate the opportunity to respond to the comments raised by Silva and Cipriano [1] regarding our recently published systematic review and meta-analysis on acute sarcopenia [2]. Constructive discussions such as this help clarify methodological considerations and enhance scientific understanding. Firstly, regarding knee extensor strength measurement, Silva and Cipriano [1] note that our review stated their study [3] did not assess knee extensor strength. We acknowledge that they measured strength using neuromuscular electrical stimulation to evoke peak force. However, our review excluded studies using electrically evoked contractions, as voluntary contractions are the recognised standard for sarcopenia assessments. This exclusion criterion was applied consistently across all studies, ensuring methodological alignment. Although we did not explicitly state this in our inclusion/exclusion criteria, we appreciate the opportunity to clarify this point. To further justify our stance on excluding this, we would like to highlight conclusions from Jenkins et al. [4] who acknowledged that voluntary and evoked contractions offer unique information to each other and should not be used interchangeably. Secondly, with reference to the sample size inclusion, we included only the control group from Silva et al.'s study, as per our inclusion criteria that specified that only control groups from intervention studies would be included. Although their total sample size was 60 participants, we reported only the control group (n = 30) as our review focused on muscle changes during hospitalisation independent of interventions. We acknowledge that this distinction could have been stated more clearly. We respectfully disagree with the claim that our review contains inaccuracies that could compromise the integrity of the scientific record. Our methodological decisions were carefully considered, transparent, and aligned with standard sarcopenia assessment practices. The exclusion of electrically evoked contraction measures was a deliberate methodological choice, as voluntary contractions are the established standard. Although this criterion was not explicitly outlined in our inclusion/exclusion criteria, it reflects a methodological decision rather than an inaccuracy. We appreciate the opportunity to clarify this and believe our approach remains clear to researchers familiar with standard assessment methods. We thank Silva et al. for their engagement and the opportunity to address these points.

Background: Acute sarcopenia is sarcopenia lasting less than six months, typically following acute illness or injury. It may impact patient recovery and quality of life, advancing to chronic sarcopenia. However, its development and assessment remain poorly understood, particularly during hospitalisation. This systematic review aimed to elucidate the incidence of acute sarcopenia and examine changes in muscle parameters during hospitalisation. Methods: Eighty-eight papers were included in the narrative synthesis; 33 provided data for meta-analyses on the effects of hospitalisation on handgrip strength (HGS), rectus femoris cross-sectional area (RFCSA) and various muscle function tests. Meta-regressions were performed for length of hospital stay (LoS) and age for all meta-analyses; sex was also considered for HGS. Results: Acute sarcopenia development was assessed in four studies with a pooled incidence of 18% during hospitalisation. Incidence was highest among trauma patients in intensive care (59%) while it was lower among medical and surgical patients (15-20%). Time of development ranged from 4-44 days. HGS remained stable during hospitalisation (SMD = 0.05, 95% CI = -0.18:0.28, P = 0.67) as did knee extensor strength. LoS affected HGS performance (θ = 0.04, 95% CI = 0.001:0.09, P = 0.045) but age (P = 0.903) and sex (P = 0.434) did not. RFCSA, reduced by 16.5% over 3 to 21 days (SMD = -0.67, 95% CI = -0.92:-0.43, P <0.001); LoS or time between scans did significantly predict the reduction (θ = -0.04, 95% CI = -0.077:-0.011, P = 0.012). Indices of muscle quality also reduced. Muscle function improved when assessed by the short physical performance battery (SMD = 0.86, 95% CI = 0.03:1.69, P = 0.046); there was no change in 6-minute walk (P = 0.22), timed up-and-go (P = 0.46) or gaitspeed tests (P = 0.98). The only significant predictor of timed up-and-go performance was age (θ = -0.11, 95% CI = -0.018:-0.005, P = 0.009). Conclusions: Assessment and understanding of acute sarcopenia in clinical settings is limited. Incidence varies between clinical conditions and muscle parameters are affected differently. HGS and muscle function tests may not be sensitive enough to identify acute changes during hospitalisation. Currently, muscle health deterioration may be underdiagnosed impacting recovery, quality of life and overall health following hospitalisation. Further evaluation is necessary to determine the suitability of existing diagnostic criteria of acute sarcopenia. Muscle mass and quality indices might need to become the primary determinants for muscle health assessment in hospitalised populations.