Novel lateral whole-body dual-energy X-ray absorptiometry of lumbar paraspinal muscle mass: results from the SarcoSpine study

Human primary myoblasts derived from paraspinal muscle reflect donor age as an experimental model of sarcopenia

BACKGROUND

Low back pain is a general phenomenon of aging, and surgery is an unavoidable choice to relieve severe back pain. The discarded surgical site during surgery is of high value for muscle and muscle-related research. This study investigated the age-dependent properties of patients' paraspinal muscles at the cellular level.

METHODS

To define an association of paraspinal muscle degeneration with sarcopenia, we analyzed lumbar paraspinal muscle and myoblasts isolated from donors of various ages (25-77 years). Preoperative evaluations were performed by bioimpedance analysis using the InBody 720, magnetic resonance (MR) imaging of the lumbar spine, and lumbar extension strength using a lumbar extension dynamometer. In addition, the growth and differentiation capacity of myoblasts obtained from the donor was determined using proliferation assay and western blotting.

RESULTS

The cross-sectional area of the lumbar paraspinal muscle decreased with age and was also correlated with the appendicular skeletal muscle index (ASM/height2). Human primary myoblasts isolated from paraspinal muscle preserved their proliferative capacity in vitro, which tended to decrease with donor age. The age-dependent decline in myoblast proliferation was correlated with levels of cell cycle inhibitory proteins (p16INK4a, p21CIP1, and p27KIP1) associated with cellular senescence. Primary myoblasts isolated from younger donors differentiated into multinucleate myotubes earlier and at a higher rate than those from older donors in vitro. Age-dependent decline in myogenic potential of the isolated primary myoblasts was likely correlated with the inactivation of myogenic transcription factors such as MyoD, myogenin, and MEF2c.

CONCLUSIONS

Myoblasts isolated from human paraspinal muscle preserve myogenic potential that correlates with donor age, providing an in vitro model of sarcopenia.

The association between morphological characteristics of paraspinal muscle and spinal disorders

BACKGROUND

Spinal disorders affect millions of people worldwide, and can cause significant disability and pain. The paraspinal muscles, located on either side of the spinal column, play a crucial role in the movement, support, and stabilization of the spine. Many spinal disorders can affect paraspinal muscles, as evidenced by changes in their morphology, including hypertrophy, atrophy, and degeneration.

OBJECTIVES

The objectives of this review were to examine the current literature on the relationship between the paraspinal muscles and spinal disorders, summarize the methods used in previous studies, and identify areas for future research.

METHODS

We reviewed studies on the morphological characteristics of the paravertebral muscle and discussed their relationship with spinal disorders, as well as the current limitations and future research directions.

RESULTS

The paraspinal muscles play a critical role in spinal disorders and are important targets for the treatment and prevention of spinal disorders. Clinicians should consider the role of the paraspinal muscles in the development and progression of spinal disorders and incorporate assessments of the paraspinal muscle function in clinical practice.

CONCLUSION

The findings of this review highlight the need for further research to better understand the relationship between the paraspinal muscles and spinal disorders, and to develop effective interventions to improve spinal health and reduce the burden of spinal disorders.

Combined exercise and nutrition intervention for older women with spinal sarcopenia: an open-label single-arm trial

PURPOSE

Spinal sarcopenia is a multifactorial disorder associated with atrophy and fatty changes in paraspinal muscles. Interventional studies for spinal sarcopenia are limited. We aimed to evaluate the effectiveness of a combined exercise and nutrition intervention for the treatment of spinal sarcopenia.

METHODS

35 community-dwelling older women diagnosed with spinal sarcopenia in a previous cohort study were included. The 12-week combined intervention consisted of back extensor strengthening exercises and protein supplementation. The following outcomes were measured at baseline (week 0), after the intervention (week 12), and follow-up (week 24): conventional variables of sarcopenia (appendicular skeletal muscle mass, handgrip strength, 6-meter gait speed, and short physical performance battery); lumbar extensor muscle mass; lumbar extensor muscle volume and signal intensity; back extensor isokinetic strength; and back performance scale. We used the intention-to-treat analysis method, and repeated measures analysis of variance was used to analyze the data.

RESULTS

Of the total 35 potential participants, 26 older women participated in the study (mean age 72.5 ± 4.0 years old). After 12 weeks of combined exercise and nutrition intervention, there were no changes in the appendicular skeletal muscle mass, lumbar extensor muscle mass, volume, or signal intensity. Handgrip strength and back extensor isokinetic strength did not change significantly. Short physical performance battery significantly increased (P = 0.042) from 11.46 ± 0.86 to 11.77 ± 0.53 at week 12 and 11.82 ± 0.40 at week 24. The back performance scale sum score also significantly improved (P = 0.034) from 2.68 ± 1.81 to 1.95 ± 1.21 at week 12 and 2.09 ± 1.34 at week 24.

CONCLUSION

The combined exercise and nutrition intervention for community-dwelling older women with spinal sarcopenia could be feasible and helpful in improving the physical performance as well as back performance.

Natural aging course of lumbar extensor muscle mass and strength in community-dwelling older women: a 1-year prospective observational study

BACKGROUND

Although the loss of skeletal limb muscle mass and muscle strength in the elderly have been demonstrated, the aging process of the back muscles to maintain core stability is not well known. This 1-year prospective observational study aimed to investigate the natural aging course of the lumbar extensor muscles (LEMs) compared with the extremity muscles and determine whether muscle strength or mass decreases more in community-dwelling older women.

METHODS

Twenty-four older urban-dwelling women aged 70 years or older were initially enrolled. Their demographic variables, conventional and spinal sarcopenia indices, and functional outcome parameters were evaluated. We also measured back extensor strength, radiological parameters for spinal sagittal balance on whole-spine radiography, and volumetric parameters of the LEM on computed tomography.

RESULTS

After the exclusion of 6 subjects, 18 older women were finally analyzed. All variables related to extremity muscle mass, muscle strength, physical performance, and LEM volume declined over the study period, but the changes were insignificant. However, back extensor strength decreased significantly (median, first, and third quartile: 35.20 [30.80, 44.00] N to 31.40 [29.25, 37.90] N, P = 0.026). Among spinal sagittal balance-related parameters, lumbar lordosis (44.25 [39.30, 47.35]° to 43.15 [31.43, 45.75]°, P = 0.043) and sagittal vertical axis (33.85 [3.57, 58.75] mm to 45.15 [25.35, 58.68] mm, P = 0.004) showed significant changes during the study.

CONCLUSIONS

When the natural aging course of LEM in women aged 70 years or older was observed for 1 year, muscle mass decreased less than back extensor strength and spinal sagittal balance. Measurements of back extensor strength and spinal sagittal balance are necessary for the clinical evaluation of spinal aging.

Novel lateral whole-body dual-energy X-ray absorptiometry of lumbar paraspinal muscle mass: results from the SarcoSpine study

BACKGROUND

Here, we aimed to propose novel lateral whole-body dual-energy X-ray absorptiometry (lateral DXA) as a simple tool for measuring spinal muscle mass and investigate the feasibility of lateral DXA to measure lumbar paraspinal muscle (LPM) mass compared with lumbosacral spine three-dimensional magnetic resonance imaging (3D MRI).

METHODS

Twenty consecutive participants were enrolled from a prospective observational cohort (SarcoSpine study). Lateral DXA was scanned with each participant in the lateral decubitus position. The region of interest was defined to analyse the LPM mass. LPM total volume, LPM cross-sectional area at the L3 mid-vertebra and L4/5 mid-disc levels and each signal intensity were measured by 3D MRI. Isokinetic and isometric back extensor muscle strengths as well as back extensor endurance were examined. The correlation between lateral DXA-based mass (weight) and 3D MRI-based LPM volume was analysed.

RESULTS

The mean age of the 20 participants (15 women, 5 men) was 72.2 ± 4.9 years. LPM mass by lateral DXA was positively correlated with LPM volume by 3D MRI (β = 0.333, r = 0.692, p < 0.001) and negatively correlated with signal intensity of the total LPM (β = -0.263, r = -0.530, p = 0.016). LPM mass was also correlated with appendicular limb muscle mass, handgrip strength and gait speed as well as back extensor endurance (r = 0.620, p = 0.004).

CONCLUSIONS

Our data suggest that LPM mass assessed by lateral DXA was positively correlated with LPM volume by 3D MRI in older adults. Lateral DXA may be a potential substitute for the cross-sectional area measurement of LPM mass. Further studies are required to validate this lateral DXA technique.