👤 Phyllis L Faust

Intrinsic Capacity (IC) is defined as the composite of physical and mental abilities an individual possesses, encompassing five domains: cognition, psychological health, sensory function, vitality, and locomotion. This construct is central to the World Health Organization's framework for assessing functional ability in older adults. Growing evidence highlights the critical role of the musculoskeletal system in maintaining these domains, while conditions such as sarcopenia, osteoporosis, and their coexistence as osteosarcopenia (OS) are increasingly associated with IC decline. This narrative review compiles current evidence on the modulatory role of muscles and bones in IC and the impacts of sarcopenia, osteoporosis, and OS. Most findings suggest that musculoskeletal tissues influence IC not only through biomechanical functions but also as secretory organs, releasing myokines and osteokines with endocrine, paracrine, and autocrine effects. Among the most studied are brain-derived neurotrophic factor, irisin, osteocalcin, and interleukin-6. Dysregulation of these pathways, along with biomechanical dysfunction and systemic inflammation, links sarcopenia, osteoporosis, and OS to IC impairment. Further research is needed to clarify the specific mechanisms involved, particularly in the sensory and vitality domains, to inform targeted interventions that promote healthy aging. Show less

The Lingo-1 sequence variant has been associated with essential tremor (ET) in several genome-wide association studies. However, the role that Lingo-1 might play in pathogenesis of ET is not understood. Since Lingo-1 protein is a negative regulator of axonal regeneration and neurite outgrowth, it could contribute to Purkinje cell (PC) or basket cell axonal pathology observed in postmortem studies of ET brains. In this study, we used Western blotting and immunohistochemistry to examine Lingo-1 protein in ET vs. control brains. In Western blots, Lingo-1 protein expression level was significantly increased in cerebellar cortex (1.56 ± 0.46 in ET cases vs. 0.99 ± 0.20 in controls, p = 0.002), but was similar in the occipital cortex (p = 1.00) of ET cases vs. controls. Lingo-1 immunohistochemistry in cerebellum revealed that Lingo-1 was enriched in the distal axonal processes of basket cells, which formed a "pinceau" structure around the PC axon initial segment (AIS). We found that some Lingo-1-positive pinceau had abnormally elongated processes, targeting PC axon segments distal to the AIS. In ET cases, the percentage of Lingo-1-positive pinceau that were ≥30 or ≥40 μm in length was increased 2.4- to 4.1-fold, respectively, vs. pinceau seen in control brains (p < 0.0001). Elongated Lingo-1-positive pinceau strongly correlated with number of PC axonal torpedoes and a rating of basket cell axonal pathology. The increased cerebellar Lingo-1 expression and elongated Lingo-1-positive pinceau processes could contribute to the abnormal PC and basket cell axonal pathology and cerebellar dysfunction observed in ET. Show less