Discover how a simple urinary biomarker is unlocking new insights into muscle strength, bone health, and physical fitness in young adults, paving the way for better health monitoring and interventions.

Short Report: Urinary pentosidine as a potential biomarker of muscle and physical performance in young adult men. Image Credit: Shutterstock AI

In a recent study published in the Journal of Physiological Anthropology, researchers assessed the associations between urinary pentosidine levels and physical performance and musculoskeletal status in young adult males.

Peak bone and muscle mass during early adulthood is essential to sustain (and prevent) bone and muscle mass losses in late adulthood. Pentosidine is representative of the crosslinked structure of advanced glycation end products that form after the oxidation of bone collagen crosslinks. Urine pentosidine levels are known to increase with age and have been associated with various health parameters in older adults.

Serum pentosidine levels have been reported to be negatively associated with muscle strength in older people. Urinary pentosidine is a risk factor for fracture in postmenopausal females, irrespective of bone density and age. Therefore, urinary pentosidine may be a valuable biomarker for assessing muscle mass and bone and muscle strength in puberty and later life.

About the study

In the present study, researchers investigated the associations of urinary pentosidine with physical performance and musculoskeletal status in young adult males. They recruited 32 Japanese males aged 19–39. A bioelectrical impedance analysis was performed to measure fat-free mass index (FFMI), skeletal muscle, and body mass.

The thickness of the anterior thigh and rectus femoris muscles of the dominant leg was measured using an ultrasound system. Further, the heel stiffness index was measured by quantitative ultrasound. The team conducted four performance tests: grip strength, a timed up and go (TUG) test, a functional reach (FR) test, and a 30-second (30-s) chair stand test.

A digital dynamometer was used to measure the grip strength of the dominant hand. The TUG test involved getting up from a chair, walking three meters forward, and returning to the chair at the usual speed. A TUG score was calculated as the average of two (TUG) trials. In the FR test, participants stood upright and extended their arms as far as possible without losing balance or stepping forward.

In the 30-s chair stand test, subjects were seated on a chair with arms crossed over the chest, knees at 90°, and flat feet; they stood up with an erect back and returned to their seated position, maintaining smooth motion and proper form throughout. Participants were asked to repeat this task as many times as possible. Further, participants provided second urine samples for biomarker analysis.

Subjects were asked to avoid drinking and eating from two hours before the experiment. High-performance liquid chromatography was performed to measure urinary pentosidine levels. Further, N-telopeptide of type 1 collagen (NTx) and cortisol levels in urine were measured using a chemiluminescent enzyme assay. Correlations between urinary biomarkers and other variables were calculated using Pearson’s correlation analysis.

Findings

The average age of participants was 24.3 years, with a mean body mass index (BMI) of 21.5 kg/m². On average, urinary pentosidine levels were 5.2 pmol/ml. The researchers observed that urinary pentosidine levels were significantly inversely correlated with FFMI, dominant grip strength, and the thickness of the dominant anterior thigh and rectus femoris muscles.

Urinary pentosidine levels were not correlated with body fat percentage. Further, a marginal inverse correlation was observed between urinary pentosidine and the FR test. The researchers also noted an inverse correlation between urinary NTx levels and the TUG score, though the physiological mechanisms behind this association remain unclear.

Conclusions

In sum, the findings illustrate inverse associations of urinary pentosidine levels with grip strength and the thickness of the dominant leg’s rectus femoris and anterior thigh muscles. Further, urinary pentosidine levels showed a marginal inverse correlation with the FR test and no associations with other physical performance parameters, such as the TUG and 30-s chair stand tests.

Urinary NTx levels were only associated with the TUG score and showed no correlation with bone mass or other metrics, which highlights the potential limitations of NTx as a biomarker for young adults.

The study’s limitations include the inability to establish causal links given the cross-sectional nature. Besides, the study could not account for the underlying confounding factors due to a limited number of parameters and the small sample size. The researchers emphasized that further investigation is needed to clarify these findings and explore the biological mechanisms involved.

Together, the findings suggest urinary pentosidine as a potential biomarker for physical performance and muscle status in young adults. In addition, the study highlights the potential value of reducing advanced glycation end product (AGE) accumulation through lifestyle interventions such as diet and exercise to preserve muscle health.