Quantification Threshold Pixel Technique of Magnetic Resonance Imaging in Paraspinal Muscles Atrophy among Discopathy Patients

Purpose: To evaluate the relationship between lumbosacral discopathy status and paraspinal atrophic changes (Cross-sectional area (CSA) and fatty infiltration (FI)) among different age groups. Materials and Methods: We retrospectively evaluated 200 patients with confirmed discopathy who were examined by lumbosacral Magnetic Resonance Imaging (MRI) at the two main governmental hospitals in Gaza Strip. Using ImageJ software and quantification threshold technique, we measured the CSA and FI of paraspinal muscles {multifidus (MF) & erector spinae (ES)}. The interpretation of MRI images was performed by two radiologists with a good inter-observer agreement between the radiological discopathy findings. Results: The highest percentage and severity of discopathy were noticed at the level of L4/5 (89.5%), followed by L5/S1 (14.5%). The FI is increased towards lower levels of L3/4 to L5/S1. No correlation was found between discopathy level, the severity of discopathy, and CSA of MF & ES muscles. In contrast, a correlation was observed between FI of MF & ES muscles, discopathy level, and severity. Also, the results illustrated no significant relation was observed between CSA of MF & ES muscles and age groups (P > 0.05), while a significant correlation was reported between FI and age groups (P Conclusion: The MRI quantification threshold pixel technique for paraspinal muscles reflected the atrophic changes like CSA and FI in discopathy patients.

Spine system changes in soldiers after load carriage training in a plateau environment: A prediction model research

Background: Low back pain is the most common spinal disorder among soldiers, and load carriage training(LCT) is considered the main cause. We aimed to investigate changes in the spine system of soldiers after LCT at high altitudes and the change trend of the lumbar spine and surrounding soft tissues under different load conditions.Methods: Magnetic resonance imaging scans of the lumbar spines of nine soldiers from plateau troops were collected and processed. We used ImageJ and Surgimap software to analyze changes in the lumbar paraspinal muscles, intervertebral discs(IVDs), intervertebral foramina, and curvature. Furthermore, the multiple linear regression equation for spine injury owing to LCT at high altitudes was established as the mathematical prediction model using SPSS Statistics version 23.0 software.Results: In the paraspinal muscles, the cross-sectional area(CSA) increased significantly from(9126.4±691.6) mm~2 to(9862.7±456.4) mm~2, and the functional CSA(FCSA) increased significantly from(8089.6±707.7) mm~2 to(8747.9±426.2) mm~2 after LCT(P<0.05);however, the FCSA/CSA was not significantly different. Regarding IVD, the total lumbar spine showed a decreasing trend after LCT with a significant difference(P<0.05). Regarding the lumbar intervertebral foramen, the percentage of the effective intervertebral foraminal area of L3/4 significantly decreased from 91.6%±2.0% to 88.1%±2.9%(P<0.05). For curvature, the lumbosacral angle after LCT(32.4°±6.8°) was significantly higher(P<0.05) than that before LCT(26.6°±5.3°), while the lumbar lordosis angle increased significantly from(24.0°±7.1°) to(30.6°±7.4°)(P<0.05). The linear regression equation of the change rate, ΔFCSA%=–0.718+23.085×load weight, was successfully established as a prediction model of spinal injury after LCT at high altitudes.Conclusion: The spinal system encountered increased muscle volume, muscle congestion, tissue edema, IVD compression, decreased effective intervertebral foramen area, and increased lumbar curvature after LCT, which revealed important pathophysiological mechanisms of lumbar spinal disorders in soldiers following short-term and high-load weight training. The injury prediction model of the spinal system confirmed that a load weight <60% of soldiers' weight cannot cause acute pathological injury after short-term LCT, providing a reference supporting the formulation of the load weight standard for LCT.

Uncovering the prominent role of satellite cells in paravertebral muscle development and aging by single-nucleus RNA sequencing

To uncover the role of satellite cells(SCs)in paravertebral muscle development and aging,we constructed a single-nucleus transcriptomic atlas of mouse paravertebral muscle across seven timepoints spanning the embryo(day 16.5)to old(month 24)stages.Eight cell types,including SCs,fast muscle cells,and slow muscle cells,were identified.An energy metabolism-related gene set,TCA CYCLE IN SENESCENCE,was enriched in SCs.Forty-two skeletal muscle disease-related genes were highly expressed in SCs and exhibited similar expression patterns.Among them,Pdha1 was the core gene in the TCA CYCLE IN SENESCENCE;Pgam2,Sod1,and Suclg1 are transcription factors closely associated with skeletal muscle energy metabolism.Transcription factor enrichment analysis of the 42 genes revealed that Myod1 and Mef2a were also highly expressed in SCs,which regulated Pdha1 expression and were associated with skeletal muscle development.These findings hint that energy metabolism may be pivotal in SCs development and aging.Three ligand-receptor pairs of extracellular matrix(ECM)-receptor interactions,Lamc1-Dag1,Lama2-Dag1,and Hspg2-Dag1,may play a vital role in SCs interactions with slow/fast muscle cells and SCs self-renewal.Finally,we built the first database of a skeletal muscle single-cell transcriptome,the Musculoskeletal Cell Atlas(http://www.mskca.tech),which lists 630,040 skeletal muscle cells and provides interactive visualization,a useful resource for revealing skeletal muscle cellular heterogeneity during development and aging.Our study could provide new targets and ideas for developing drugs to inhibit skeletal muscle aging and treat skeletal muscle diseases.