Spinal motor neurons and motor function in older adults

Abstract

This study examined the relation of lumbar spinal motor neuron (SMN) indices and motor function proximate to death in community-dwelling older adults. Older adults (N=145) participating in the Rush Memory and Aging Project underwent structured clinical testing proximate to death and brain and spinal cord autopsy at time of death. Ten motor performances were summarized by a composite global motor score. Choline acetyltransferase immunostaining was used to identify spinal motor neurons of the L4/5 segment. SMN counts and area and ventral horn area were collected. Linear regression modeling showed that the association of SMN counts and density with global motor scores proximate to death varied with sex. Separate models in men and women showed that this significant interaction was due to the association of higher SMN counts and density with higher global motor scores proximate to death in men but not women. These associations were unchanged when we controlled for indices of brain pathologies or chronic health conditions. In 38 cases with counts of activated microglia available, higher counts of activated microglia were associated with lower SMN counts. Activated spinal microglia and loss of spinal motor neurons may contribute to motor impairments in older men.

Compensation vestibulaire et vieillissement

“…Les motoneurones spinaux sont aussi touchés par le vieillissement : la réduction de leur nombre s'accompagne de niveaux d'activation de la microglie plus élevés. Ces données suggèrent que la perte de motoneurones spinaux chez les personnes âgées peut contribuer, en partie, à une déficience motrice tardive [33]. [36].…”

Physical Activity in the Elderly and Orthopaedic Surgery

“…Regarding rotator cuff tendinopathy, there is consistent evidence that both focused shock wave therapy and radial pressure wave treatment reduce pain and improve shoulder function when degenerative tendinopathy is present [76,77]. Conversely, extracorporeal shock wave therapies may be less effective for calcific rotator cuff tendinopathy, while ultrasound-guided percutaneous irrigation treatment [55,[78][79][80], also known as ultrasound-guided lavage [80], seems to be more effective than physical therapies or corticosteroid injection [80].…”

Central and Peripheral Neuromuscular Adaptations to Ageing

“…In addition, the loss of motor neurons appears to be associated with an increase in the number of astrocytes as well as an alteration of the dendritic networks [74]. Several human studies also reported a reduction in the density and diameter of myelinated and unmyelinated axons in the ventral horns of the spinal cord of aged individuals [75][76][77][78][79][80]. Jacobs and Love [81] demonstrated that old adults show a decline in myelinated and unmyelinated fibres of 38% compared to young adults.…”