PMID- 32749719 OWN - NLM STAT- MEDLINE DCOM- 20211018 LR - 20211018 IS - 1469-445X (Electronic) IS - 0958-0670 (Linking) VI - 105 IP - 10 DP - 2020 Oct TI - Epidural stimulation for cardiovascular function increases lower limb lean mass in individuals with chronic motor complete spinal cord injury. PG - 1684-1691 LID - 10.1113/EP088876 [doi] AB - NEW FINDINGS: What is the central question of this study? Spinal cord injury results in paralysis and deleterious neuromuscular and autonomic adaptations. Lumbosacral epidural stimulation can modulate motor and/or autonomic functions. Does long-term epidural stimulation for normalizing cardiovascular function affect leg muscle properties? What is the main finding and its importance? Leg lean mass increased after long-term epidural stimulation for cardiovascular function, which was applied in the sitting position and did not activate the leg muscles. Leg muscle strength and fatigue resistance, assessed in a subgroup of individuals, also increased. These adaptations might support interventions for motor recovery and warrant further mechanistic investigation. ABSTRACT: Chronic motor complete spinal cord injury (SCI) results in paralysis and deleterious neuromuscular and autonomic adaptations. Paralysed muscles demonstrate atrophy, loss of force and increased fatigability. Also, SCI-induced autonomic impairment results in persistently low resting blood pressure and heart rate, among other features. We previously reported that spinal cord epidural stimulation (scES) optimized for cardiovascular (CV) function (CV-scES), which is applied in sitting position and does not activate the leg muscles, can maintain systolic blood pressure within a normotensive range during quiet sitting and during orthostatic stress. In the present study, dual-energy X-ray absorptiometry collected from six individuals with chronic clinically motor complete SCI demonstrated that 88 +/- 11 sessions of CV-scES (7 days week(-1) ; 2 h day(-1) in four individuals and 5 h day(-1) in two individuals) over a period of approximately 6 months significantly increased lower limb lean mass (by 0.67 +/- 0.39 kg or 9.4 +/- 8.1%; P < 0.001). Additionally, muscle strength and fatigability data elicited by neuromuscular electrical stimulation in three of these individuals demonstrated a general increase (57 +/- 117%) in maximal torque output (between 2 and 44 N m in 14 of the 17 muscle groups tested overall) and torque-time integral during intermittent, fatiguing contractions (63 +/- 71%; between 7 and 230% in 16 of the 17 muscle groups tested overall). In contrast, whole-body mass and composition did not change significantly. In conclusion, long-term use of CV-scES can have a significant impact on lower limb muscle properties after chronic motor complete SCI. CI - (c) 2020 The Authors. Experimental Physiology (c) 2020 The Physiological Society. FAU - Legg Ditterline, Bonnie AU - Legg Ditterline B AD - Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA. AD - Department of Neurological Surgery, University of Louisville, Louisville, KY, USA. FAU - Harkema, Susan J AU - Harkema SJ AD - Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA. AD - Department of Neurological Surgery, University of Louisville, Louisville, KY, USA. AD - Frazier Rehabilitation Institute, University of Louisville Health, Louisville, KY, USA. AD - Department of Bioengineering, University of Louisville, Louisville, KY, USA. FAU - Willhite, Andrea AU - Willhite A AD - Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA. FAU - Stills, Sean AU - Stills S AD - Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA. FAU - Ugiliweneza, Beatrice AU - Ugiliweneza B AD - Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA. AD - Department of Neurological Surgery, University of Louisville, Louisville, KY, USA. FAU - Rejc, Enrico AU - Rejc E AUID- ORCID: 0000-0001-9368-2220 AD - Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, USA. AD - Department of Neurological Surgery, University of Louisville, Louisville, KY, USA. LA - eng GR - Leona M. and Harry B. Helmsley Charitable Trust/ GR - Christopher and Dana Reeve Foundation/ GR - Craig H. Neilsen Foundation/ PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20200815 PL - England TA - Exp Physiol JT - Experimental physiology JID - 9002940 SB - IM MH - Adaptation, Physiological/physiology MH - Adult MH - Cardiovascular System/*physiopathology MH - Epidural Space/*physiopathology MH - Female MH - Humans MH - Leg/*physiopathology MH - Male MH - Muscle Contraction/physiology MH - Muscle Strength/physiology MH - Muscle, Skeletal/physiopathology MH - Paralysis/physiopathology MH - Spinal Cord/*physiopathology MH - Spinal Cord Injuries/*physiopathology MH - Spinal Cord Stimulation/methods MH - Torque MH - Young Adult OTO - NOTNLM OT - cardiovascular function OT - muscle hypertrophy OT - muscle properties OT - spinal cord epidural stimulation OT - spinal cord injury EDAT- 2020/08/05 06:00 MHDA- 2021/10/21 06:00 CRDT- 2020/08/05 06:00 PHST- 2020/06/26 00:00 [received] PHST- 2020/07/31 00:00 [accepted] PHST- 2020/08/05 06:00 [pubmed] PHST- 2021/10/21 06:00 [medline] PHST- 2020/08/05 06:00 [entrez] AID - 10.1113/EP088876 [doi] PST - ppublish SO - Exp Physiol. 2020 Oct;105(10):1684-1691. doi: 10.1113/EP088876. Epub 2020 Aug 15.