Muscle Quantity, Quality, Function, and Biomarker Associations with Longitudinal Preservation of Bone Microarchitecture and Bone Strength in Older Adults
openNIAMS - National Institute of Arthritis and Musculoskeletal and Skin Diseases
The long-term goal of the project is to substantially improve the understanding of how muscle
impacts bone loss. Muscle and bone may be connected via mechanostat loading, as bone
adapts its morphology and strength from muscle contraction, or by bidirectional muscle-bone
signaling, which occurs beyond a purely mechanical perspective. We propose to examine
comprehensive muscle associations of maximal capacity of muscle to generate ATP (ATP max)
by 31P-Magnetic Resonance Spectroscopy (31P–MRS), quadriceps (thigh) contractile volume
by MRI, total muscle mass by D3 creatine dilution (D3Cr), muscle function (strength and power),
and myokines with 5-year longitudinal change in bone density, microarchitecture and strength
outcomes. The underlying scientific premise is that age-related decreases in the muscle ATP,
volume, total mass, function and myokines lead to declines in bone density, microarchitecture
and strength. This project leverages the recent renewal of the Study of Muscle, Mobility and
Aging (SOMMA), the first prospective study of muscle aging, which evaluates the role of skeletal
muscle to major mobility disability. In the first follow-up, we added measures of bone density,
microarchitecture and strength (failure load by finite element analysis) using high-resolution
peripheral quantitative computed tomography (HR-pQCT) in 327/385 (85%) of men and women
(76+5 years; 61% women) in Pittsburgh, PA. We anticipate 294 will repeat an HR-pQCT scan at
Visit 6 to determine: Aim 1, muscle energetics, mass, volume, and function (power, strength)
associations with 5-year change in HR-pQCT bone density, microarchitecture, and strength; and
Aim 2, if myokines (D-, L-BAIBA, GABA, and L-AABA aminobutyric acids) are associated with
cross-sectional and 5-year change in HR-pQCT bone parameters. We will examine trabecular
and cortical bone parameters in a weight bearing (tibia) and non-weight bearing (radius) bone
site, adjust for key risk factors (e.g., BMI, physical activity) and evaluate if bone biomarkers
(CTX-1, P1NP) explain associations. To our knowledge, no studies have linked ATP-max and
thigh contractile volume to longitudinal changes volumetric BMD, microarchitecture and
strength, or evaluated D3Cr and these longitudinal HR-pQCT changes on both older men and
women. Our SOMMA ancillary study offers a cost-efficient opportunity to investigate muscle-
bone longitudinal change using state-of-the-art measures. We will be the first to study novel
properties of muscle energetics, mass, volume and function, and myokines, in association with
changes in bone strength and microarchitecture in a well-characterized population of older men
and women. We may potentially identify targeted muscle pathways that improve bone tissue.
Up to $1.6M
health research