Photobiomodulation therapy (red/NIR LEDs) reduced the length of stay in intensive care unit and improved muscle function: A randomized, triple-blind, and sham-controlled trial

Photobiomodulation therapy (PBMT) in skeletal muscle regeneration: A comprehensive review of mechanisms, clinical applications, and future directions

Photobiomodulation therapy (PBMT) emerged as a significant non-invasive method of stimulating regeneration of the skeletal muscle tissue. This review considers the pathophysiologic and molecular mechanisms of muscle repair, with a focus on the imperative of inflammation resolution, activation of satellite cells, mitochondrial ATP generation, and angiogenesis, with consideration of the role of PBMT. We systematically evaluate preclinical and clinical studies, highlighting the translational gaps caused by differences between controlled experimental models and the complex, heterogeneous nature of human muscle injuries. Variability in PBMT parameters-such as wavelength, fluence, and pulse mode-and the lack of standardized protocols are identified as major barriers to consistent therapeutic outcomes. Furthermore, we discuss the effects of PBMT in acute and chronic muscle injury models and provide an in-depth analysis of laser parameters to elucidate dose-response relationships. Future directions for research involve the application of real-time biofeedback devices, the utilization of artificial intelligence-based individualized therapeutic approaches, as well as the integration of photobiomodulation therapy with nanotechnology, biomaterials, and multiple mechanical stimulation methods. In concusion, while PBMT has significant potential for muscle regeneration therapies, its clinical application requires more complete mechanistic validation, rigorous standardization, and interdisciplinary technological development.

Acute Sarcopenia: Systematic Review and Meta-Analysis on Its Incidence and Muscle Parameter Shifts During Hospitalisation

BACKGROUND

Acute sarcopenia is sarcopenia lasting less than 6 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%), whereas it was lower among medical and surgical patients (15%-20%). Time of development ranged from 4 to 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 3-21 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-min walk (p = 0.22), timed up-and-go (p = 0.46) or gait speed 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 are 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.