Electrically polarized nanoscale surfaces generate reactive oxygenated and chlorinated species for deactivation of microorganisms.

Because of the decreasing supply of new antibiotics, recent outbreaks of infectious diseases, and the emergence of antibiotic-resistant microorganisms, it is imperative to develop new effective strategies for deactivating a broad spectrum of microorganisms and viruses. We have implemented electrically polarized nanoscale metallic (ENM) coatings that deactivate a wide range of microorganisms including Gram-negative and Gram-positive bacteria with greater than 6-log reduction in less than 10 minutes of treatment. The electrically polarized devices were also effective in deactivating lentivirus and Candida albicans. The key to the high deactivation effectiveness of ENM devices is electrochemical production of micromolar cuprous ions, which mediated reduction of oxygen to hydrogen peroxide. Formation of highly damaging species, hydroxyl radicals and hypochlorous acid, from hydrogen peroxide contributed to antimicrobial properties of the ENM devices. The electric polarization of nanoscale coatings represents an unconventional tool for deactivating a broad spectrum of microorganisms through in situ production of reactive oxygenated and chlorinated species.

Translational mobility medicine and ugo carraro: a life of significant scientific contributions reviewed in celebration.

Prof. Ugo Carraro reached 80 years of age on 23 February 2023, and we wish to celebrate him and his work by reviewing his lifetime of scientific achievements in Translational Myology. Currently, he is a Senior Scholar with the University of Padova, Italy, where, as a tenured faculty member, he founded the Interdepartmental Research Center of Myology. Prof. Carraro, a pioneer in skeletal muscle research, is a world-class expert in structural and molecular investigations of skeletal muscle biology, physiology, pathology, and care. An authority in bidimensional gel electrophoresis for myosin light chains, he was the first to separate mammalian muscle myosin heavy chain isoforms by SDS-gel electrophoresis. He has demonstrated that long-term denervated muscle can survive denervation by myofiber regeneration, and shown that an athletic lifestyle has beneficial impacts on muscle reinnervation. He has utilized his expertise in translational myology to develop and validate rehabilitative treatments for denervated and ageing skeletal muscle. He has authored more than 160 PubMed listed papers and numerous scholarly books, including his recent autobiography. Prof. Carraro founded and serves as Editor-in-Chief of the European Journal of Translational Myology and Mobility Medicine. He has organized more than 40 Padua Muscle Days Meetings and continues this, encouraging students and young scientists to participate. As he dreams endlessly, he is currently validating non-invasive analyses on saliva, a promising approach that will allow increased frequency sampling to analyze systemic factors during the transient effects of training and rehabilitation by his proposed Full-Body in- Bed Gym for bed-ridden elderly.

Five Padua days on muscle and mobility medicine (2024Pdm3) 27 February - 2 March, 2024 at Hotel Petrarca, Thermae of Euganean Hills, Padua, and San Luca Hall, Prato della Valle, Padua, Italy.

At the end of the 2023 Padua Days of Muscle and Mobility Medicine the next year's meeting was scheduled from 27 February to 2 March 2024 (2024Pdm3). During the summer and autumn the program was confirmed with Scientific Sessions that will take place over five days, starting in the afternoon of February 27, 2024 at the Conference Room of the Hotel Petrarca, Thermae of Euganean Hills (Padua), Italy. As usual, the next day will be spent in Padua, in this occasion at the San Luca Hall of the Santa Giustina monastery in Prato della Valle, Padua, Italy. Collected during Autumn 2023, many more titles and abstracts than expected were submitted, forcing the organization of parallel sessions both on March 1 and March 2 2024 confirming attractiveness of the 2024 Pdm3. The five days will include oral presentations of scientists and clinicians from Argentina, Austria, Belgium, Brazil, Canada, Denmark, Egypt, France, Germany, Iceland, Ireland, Italy, Romania, Russia, Slovenia, Switzerland, UK and USA. Together with the preliminary Program at December 1, 2023, the early submitted Abstracts is e-published in this Issue 33 (4) 2023 of the European Journal of Translational Myology (EJTM). You are invited to join, submitting your Last Minute Abstracts to ugo.carraro@unipd.it by February 1, 2024. Furthermore, with the more generous deadline of May 20, 2024, submit please "Communications" to the European Journal of Translational Myology (Clarivate's ESCI Impact factor 2.2; SCOPUS Cite Score: 3.2). See you soon at the Hotel Petrarca in Montegrotto Terme, Padua, on February 27, 2024, but the complete program can be followed from home via zoom connection.

Aerobic training and vitamin E administration ameliorates cardiac apoptosis markers in rats exposed to methamphetamine.

Methamphetamine (MA) abuse is related to risks to the cardiovascular system. The present study aimed to compare the effects of moderate-intensity aerobic training (MIAT) and vitamin E (Vit.E) supplementation on markers of cardiac apoptosis following MA exposure. Fifty-four rats were randomly divided into six groups. CON group did not receive MA, while the others received MA alone or in combination with MIAT, Vit. E, MIAT+Vit E, or paraffin (PAR). These groups received MA incrementally for 23 consecutive days. Vit.E and MIAT+Vit.E groups received vitamin E three times a week for six weeks. MIAT and MIAT+Vit.E groups exercised for 25-40 min. Immunohistochemical and gene expression analyses were performed on the heart tissues. Bax and TGF-ß expression was significantly higher, while Bcl-2 and VEGF expression was significantly lower in the MA and PAR groups than in the other groups (p < 0.05). Bcl-2 and VEGF expression was higher, and Bax and TGF-ß expression was significantly lower in the MIAT and MIAT+Vit.E groups than in the other groups (p < 0.05). In Vit.E treated groups, Bax and TGF-ß expression were lower, and VEGF was higher than that in the MA and PAR groups, but higher than those in the CON, MIAT and MIAT+Vit.E groups. MA increased the expression of Bax and TGF-ß, and decreased the expression of Bcl-2 and VEGF, suggesting increased cardiac apoptosis. In contrast, MIAT and Vit.E decreased the expression of Bax and TGF-ß, suggesting a reduction in cardiac apoptosis induced by MA.

Reinnervation of Vastus lateralis is increased significantly in seniors (70-years old) with a lifelong history of high-level exercise (2013, revisited here in 2022).

In 2013 we presented results showing that at the histological level lifelong increased physical activity promotes reinnervation of muscle fibers in aging muscles. Indeed, in muscle biopsies from 70-year old men with a lifelong history of high-level physical activity, we observed a considerable increase in fiber-type groupings (F-TG), almost exclusively of the slow type. Slow-type transformation by denervation-reinnervation in senior sportsmen seems to fluctuate from those with scarce fiber-type transformation and groupings to almost fully transformed muscle, going through a process in which isolated fibers co-expressing fast and slow Myosin Heavy Chains (MHCs) seems to fill the gaps. Taken together, our results suggest that, beyond the direct effects of aging on the muscle fibers, changes occurring in skeletal muscle tissue appear to be largely, although not solely, a result of sparse denervation-reinnervation. The lifelong exercise allows the body to adapt to the consequences of the age-related denervation and to preserve muscle structure and function by saving otherwise lost muscle fibers through recruitment to different, mainly slow, motor units. These beneficial effects of high-level life-long exercise on motoneurons, specifically on the slow type motoneurones that are those with higher daily activity, and on muscle fibers, serve to maintain size, structure and function of muscles, delaying the functional decline and loss of independence that are commonly seen in late aging. Several studies of independent reserchers with independent analyses confirmed and cited our 2013 results. Thus, the results we presented in our paper in 2013 seem to have held up rather well.

The ERG1A K+ Channel Is More Abundant in Rectus abdominis Muscle from Cancer Patients Than that from Healthy Humans.

BACKGROUND: The potassium channel encoded by the ether-a-gogo-related gene 1A (erg1a) has been detected in the atrophying skeletal muscle of mice experiencing either muscle disuse or cancer cachexia and further evidenced to contribute to muscle deterioration by enhancing ubiquitin proteolysis; however, to our knowledge, ERG1A has not been reported in human skeletal muscle. METHODS AND RESULTS: Here, using immunohistochemistry, we detect ERG1A immunofluorescence in human Rectus abdominis skeletal muscle sarcolemma. Further, using single point brightness data, we report the detection of ERG1A immunofluorescence at low levels in the Rectus abdominis muscle sarcolemma of young adult humans and show that it trends toward greater levels (10.6%) in healthy aged adults. Interestingly, we detect ERG1A immunofluorescence at a statistically greater level (53.6%; p < 0.05) in the skeletal muscle of older cancer patients than in age-matched healthy adults. Importantly, using immunoblot, we reveal that lower mass ERG1A protein is 61.5% (p < 0.05) more abundant in the skeletal muscle of cachectic older adults than in healthy age-matched controls. Additionally, we report that the ERG1A protein is detected in a cultured human rhabdomyosarcoma line that may be a good in vitro model for the study of ERG1A in muscle. CONCLUSIONS: The data demonstrate that ERG1A is detected more abundantly in the atrophied skeletal muscle of cancer patients, suggesting it may be related to muscle loss in humans as it has been shown to be in mice experiencing muscle atrophy as a result of malignant tumors.

MERG1A Protein Abundance Increases in the Atrophied Skeletal Muscle of Denervated Mice, But Does Not Affect NFκB Activity.

Skeletal muscle atrophy may occur with disease, injury, decreased muscle use, starvation, and normal aging. No reliably effective treatments for atrophy are available, thus research into the mechanisms contributing to muscle loss is essential. The ERG1A K+ channel contributes to muscle loss by increasing ubiquitin proteasome proteolysis (UPP) in the skeletal muscle of both unweighted and cachectic mice. Because the mechanisms which produce atrophy vary based upon the initiating factor, here we investigate atrophy produced by denervation. Using immunohistochemistry and immunoblots, we demonstrate that ERG1A protein abundance increases significantly in the Gastrocnemius muscle of rodents 7 days after both sciatic nerve transection and hind limb unweighting. Further, we reveal that ectopic expression of a Merg1a encoded plasmid in normal mouse Gastrocnemius muscle has no effect on activity of the NFκB transcription factor family, a group of proteins which contribute to muscle atrophy by modulation of the UPP. Further, although NFκB activity increases significantly after denervation, we show that expression of a plasmid encoding a dominant negative Merg1a mutant in Gastrocnemius muscle prior to denervation, has no effect on NFκB activity. Thus, although the ERG1A K+ channel increases UPP, it does not do so through modulation of NFκB transcription factors.

The ERG1a potassium channel increases basal intracellular calcium concentration and calpain activity in skeletal muscle cells.

BACKGROUND: Skeletal muscle atrophy is the net loss of muscle mass that results from an imbalance in protein synthesis and protein degradation. It occurs in response to several stimuli including disease, injury, starvation, and normal aging. Currently, there is no truly effective pharmacological therapy for atrophy; therefore, exploration of the mechanisms contributing to atrophy is essential because it will eventually lead to discovery of an effective therapeutic target. The ether-a-go-go related gene (ERG1A) K+ channel has been shown to contribute to atrophy by upregulating ubiquitin proteasome proteolysis in cachectic and unweighted mice and has also been implicated in calcium modulation in cancer cells. METHODS: We transduced C2C12 myotubes with either a human ERG1A encoded adenovirus or an appropriate control virus. We used fura-2 calcium indicator to measure intracellular calcium concentration and Calpain-Glo assay kits (ProMega) to measure calpain activity. Quantitative PCR was used to monitor gene expression and immunoblot evaluated protein abundances in cell lysates. Data were analyzed using either a Student's t test or two-way ANOVAs and SAS software as indicated. RESULTS: Expression of human ERG1A in C2C12 myotubes increased basal intracellular calcium concentration 51.7% (p < 0.0001; n = 177). Further, it increased the combined activity of the calcium-activated cysteine proteases, calpain 1 and 2, by 31.9% (p < 0.08; n = 24); these are known to contribute to degradation of myofilaments. The increased calcium levels are likely a contributor to the increased calpain activity; however, the change in calpain activity may also be attributable to increased calpain protein abundance and/or a decrease in levels of the native calpain inhibitor, calpastatin. To explore the enhanced calpain activity further, we evaluated expression of calpain and calpastatin genes and observed no significant differences. There was no change in calpain 1 protein abundance; however, calpain 2 protein abundance decreased 40.7% (p < 0.05; n = 6). These changes do not contribute to an increase in calpain activity; however, we detected a 31.7% decrease (p < 0.05; n = 6) in calpastatin which could contribute to enhanced calpain activity. CONCLUSIONS: Human ERG1A expression increases both intracellular calcium concentration and combined calpain 1 and 2 activity. The increased calpain activity is likely a result of the increased calcium levels and decreased calpastatin abundance.

IFN-γ and CIITA modulate IL-6 expression in skeletal muscle.

Interleukin 6 (IL-6) is a secreted cytokine that is an important mediator of the immune response in numerous tissues, including skeletal muscle. IL-6 is considered a myokine as it can be secreted by muscle. IL-6 is secreted following exercise, where it exerts both pro-myogenic effects as well as anti-myogenic effects such as promoting atrophy and muscle wasting. The regulation of IL-6 in skeletal muscle is not well understood. The purpose of this study was to determine if IFN-γ and TNF-ɑ stimulate IL-6 in skeletal muscle. We found that both IFN-γ and TNF-α stimulate IL-6 in skeletal muscle, but the stimulation is not cooperative as seen in monocytes. We have previously shown that the IFN-γ stimulated class II major histocompatibility complex transactivator (CIITA) mediates many of the effects of IFN-γ in skeletal muscle and we show here that CIITA directly stimulates IL-6. The regulation of IL-6 by CIITA is clearly complex, as we found that CIITA both stimulates and restrains IL-6 expression. To show that these effects could be observed in a physiological setting, mice were treated with IFN-γ and we found that both CIITA and IL-6 were upregulated in skeletal muscle.

Two-years of home based functional electrical stimulation recovers epidermis from atrophy and flattening after years of complete Conus-Cauda Syndrome.

To evaluate progression of skin atrophy during 8 years of complete Conus-Cauda Syndrome and its recovery after 2 years of surface Functional Electrical Stimulation a cohort study was organized and implemented.Functional assessments, tissue biopsies, and follow-up were performed at the Wilhelminenspital, Vienna, Austria; skin histology and immunohistochemistry at the University of Padova, Italy on 13 spinal cord injury persons suffering up to 10 years of complete conus/cauda syndrome. Skin biopsies (n. 52) of both legs were analyzed before and after 2 years of home-based Functional Electrical Stimulation delivered by large anatomically shaped surface electrodes placed on the skin of the anterior thigh. Using quantitative histology we analyzed: 1. Epidermis atrophy by thickness and by area; 2. Skin flattening by computing papillae per mm and Interdigitation Index of dermal-epidermal junctions; 3. Presence of Langerhans cells.Linear regression analyses show that epidermal atrophy and flattening worsen with increasing years post- spinal cord injury and that 2 years of skin electrostimulation by large anatomically shaped electrodes reverses skin changes (pre-functional Electrical Stimulation vs post-functional Electrical Stimulation: thickness 39%, P < .0001; area 41%, P < .0001; papillae n/mm 35%, P < 0.0014; Interdigitation index 11%, P < 0.018), producing a significant recovery to almost normal levels of epidermis thickness and of dermal papillae, with minor changes of Langerhans cells, despite 2 additional years of complete Conus-Cauda Syndrome.In complete Conus-Cauda Syndrome patients, the well documented beneficial effects of 2 years of surface h-b Functional Electrical Stimulation on strength, bulk, and muscle fiber size of thigh muscles are extended to skin, suggesting that electrical stimulation by anatomically shaped electrodes fixed to the skin is also clinically relevant to counteract atrophy and flattening of the stimulated skin. Mechanisms, pros and cons are discussed.

Ether-a-go-go related gene-1a potassium channel abundance varies within specific skeletal muscle fiber type.

The ERG1A K+ channel, which is partially responsible for repolarization of the cardiac action potential, has also been reported in skeletal muscle where it modulates ubiquitin proteolysis. Because ERG1A protein appears variably expressed in muscles composed of mixed fiber types, we hypothesized that its abundance in skeletal muscle might differ with fiber type. Indeed, skeletal muscle fibers vary in speed of contraction (fast or slow), which is mainly determined by myosin heavy chain (MyHC) isoform content, but a sarcolemmal K+ channel might also modulate contraction speed. To test our hypothesis, we cryo-sectioned Soleus (SOL), Extensor Digitorum Longus (EDL), and Gastrocnemius muscles from five rats. These muscles were chosen because the SOL and EDL contain an abundance of slow- and fast-twitch fibers, respectively, while the Gastrocnemius has a more heterogeneous composition. The muscle sections were co-immunostained for the ERG1A protein and either the fast- or slow-twitch MyHC to identify fiber type. ERG1A fluorescence was then measured in the sarcolemma of each fiber type and compared. The data reveal that the ERG1A protein is more abundant in the fibers of the SOL than in the EDL muscles, suggesting ERG1A may be more abundant in the slow than the fast fibers, and this was confirmed with immunoblot. However, because of the homogeneity of fiber type within these muscles, it was not possible to get enough data from both fiber types within a single muscle to compare ERG1A composition within fiber type. However, immunohistochemistry of sections from the fiber type heterogeneous Gastrocnemius muscle reveals that slow fibers had, on average, a 17.2% greater ERG1A fluorescence intensity than fast fibers (p<0.03). Further, immunoblot reveals that ERG1A protein is 41.6% more abundant (p=0.051) in old than in young rat Gastrocnemius muscle. We postulate that this membrane bound voltage-gated channel may affect membrane characteristics, the duration of the action potential generated, and/or the speed of contraction. Indeed, ERG1A protein is more abundant in aged and atrophic skeletal muscle, both of which exhibit slower rates of contraction.

To Reverse Atrophy of Human Muscles in Complete SCI Lower Motor Neuron Denervation by Home-Based Functional Electrical Stimulation.

After spinal cord injury (SCI), patients spend daily several hours in wheelchairs, sitting on their hamstring muscles. SCI causes muscle atrophy and wasting, which is especially severe after complete and permanent damage to lower motor neurons. A European Union (EU)-supported work demonstrates that electrical fields produced by large electrodes and purpose-developed electrical stimulators recover both quadriceps and hamstring muscles, producing a cushioning effect capable of benefitting SCI patients, even in the worst case of complete and long-term lower motor neuron denervation of leg muscles. We reported that 20 out of 25 patients completed a 2-year h-bFES program, which resulted in (1) a 35% increase in cross-sectional area of the quadriceps muscles (P < 0.001), (2) a 75% increase in mean diameter of quadriceps muscle fibers (P < 0.001), and (3) improvement of the ultrastructural organization of contractile machinery and of the Ca2+-handling system. Though not expected, after 2 years during which the 20 subjects performed 5 days per week h-bFES of the atrophic quadriceps muscles, the CT cross-sectional area of the hamstring muscles also augmented, increasing from 26.9+/-8.4 (cm2) to 30.7+/-9.8 (cm2), representing a significant (p ≤ 0.05) 15% increase. Here we show by quantitative muscle color computed tomography (QMC-CT) that h-bFES-induced tissue improvements are present also in the hamstring muscles: a once supposed drawback (lack of specificity of muscle activation by large surface electrodes) is responsible for a major positive clinical effect. Interestingly, 2 years of home-based FES by large surface electrodes reversed also the denervation-induced skin atrophy, increasing epidermis thickness. Finally, we would like to attract attention of the readers to quantitative muscle color computed tomography (QMC-CT), a sensitive quantitative imaging analysis of anatomically defined skeletal muscles introduced by our group to monitor atrophy/degeneration of skeletal muscle tissue. Worldwide acceptance of QMC-CT will provide physicians an improved tool to quantitate skeletal muscle atrophy/degeneration before and during rehabilitation strategies so that therapy for mobility-impaired persons can be better prescribed, evaluated, and altered where needed.

In complete SCI patients, long-term functional electrical stimulation of permanent denervated muscles increases epidermis thickness.

Our studies have shown that atrophic Quadriceps muscles from spinal cord injury patients suffering with permanent denervation-induced atrophy and degeneration of muscle fibers, were almost completely rescued to normal size after two years of home-based functional electrical stimulation (h-bFES). Because we used surface electrodes to stimulate the muscle, we wanted to know how the skin was affected by the treatments. Here, we report preliminary data from histological morphometry of Hematoxylin-Eosin-stained paraffin-embedded skin sections harvested from the legs of three SCI patients before and after two years of h-bFES. Despite the heterogeneity of gender and time from SCI, comparing pre vs post h-bFES in these three SCI patients, the data show that: (1) In one subject skin biopsies from both the right and left leg experienced a statistically significant increase in thickness of the epidermis after two years of H-bFES; (2) In the other two subjects, one leg showed a significant increase in epidermis thickness, while in the other leg there was either small positive or negative non-significant changes in epidermis thickness; and (3) more importantly, comparison of grouped data from the three subjects shows that there was a significant 28% increase in the thickness of the epidermis in response to two years of h-bFES rehabilitation. In conclusion, the three educational cases show a long-term positive modulation of epidermis thickness after two years of h-bFES, thus extending to skin the positive results previously demonstrated in skeletal muscle, specifically, a substantial recovery of muscle mass and contractile function after long-term h-bFES.

Acrolein-mediated neuronal cell death and alpha-synuclein aggregation: Implications for Parkinson's disease.

Growing evidence suggests that oxidative stress plays a critical role in neuronal destruction characteristic of Parkinson's disease (PD). However, the molecular mechanisms of oxidative stress-mediated dopaminergic cell death are far from clear. In the current investigation, we tested the hypothesis that acrolein, an oxidative stress and lipid peroxidation (LPO) product, is a key factor in the pathogenesis of PD. Using a combination of in vitro, in vivo, and cell free models, coupled with anatomical, functional, and behavioral examination, we found that acrolein was elevated in 6-OHDA-injected rats, and behavioral deficits associated with 6-OHDA could be mitigated by the application of the acrolein scavenger hydralazine, and mimicked by injection of acrolein in healthy rats. Furthermore, hydralazine alleviated neuronal cell death elicited by 6-OHDA and another PD-related toxin, rotenone, in vitro. We also show that acrolein can promote the aggregation of alpha-synuclein, suggesting that alpha-synuclein self-assembly, a key pathological phenomenon in human PD, could play a role in neurotoxic effects of acrolein in PD models. These studies suggest that acrolein is involved in the pathogenesis of PD, and the administration of anti-acrolein scavengers such as hydralazine could represent a novel strategy to alleviate tissue damage and motor deficits associated with this disease.

Muscle and skin improve by home-based FES and full-body in-bed gym.

All progressive muscle contractile impairments, including advanced age-related muscle power decline, need permanent management. Most elderly persons, in particular octogenarians, spend small amounts of time in daily physical activity, resulting in a decline in body condition with more and more frequent hospitalizations and finally potentially forcing them to bed permanently. Further several neurological injuries, which are even more acutely debilitating than those problems related to aging, are responsible for early limitation of mobility. Inspired by the proven capability to recover skeletal muscle contractility and strength by home-based functional electrical stimulation (h-bFES) in both elderly and SCI patients, we suggest that the elderly and early aging patients participate in hbFES and add a 20 min daily routine of 12 easy and safe physical exercises, namely home-based Full-Body In-Bed Gym. Continued regularly, h-bFES and the Full-Body In-Bed Gym will help to maintain the independence of frail older people and may reduce the risks of serious consequences of accidental falls and pressure sore complications.

Atrophy, ultra-structural disorders, severe atrophy and degeneration of denervated human muscle in SCI and Aging. Implications for their recovery by Functional Electrical Stimulation, updated 2017.

OBJECTIVES: Long-term lower motor neuron denervation of skeletal muscle is known to result in degeneration of muscle with replacement by adipose and fibrotic tissues. However, long-term survival of a subset of skeletal myofibers also occurs. METHODS: We performed transverse and longitudinal studies of patients with spinal cord injury (SCI), patients specifically complete Conus and Cauda Equina Syndrome and also of active and sedentary seniors which included analyses of muscle biopsies from the quadriceps m. RESULTS: Surprisingly, we discovered that human denervated myofibers survive years of denervation after full and irreversible disconnection from their motor neurons. We found that atrophic myofibers could be rescued by home-based Functional Electrical Stimulation (h-bFES), using purpose developed stimulators and electrodes. Although denervated myofibers quickly lose the ability to sustain high-frequency contractions, they respond to very long impulses that are able to allow for re-emergence of tetanic contractions. A description of the early muscle changes in humans are hampered by a paucity of patients suffering complete Conus and Cauda Equina Syndrome, but the cohort enrolled in the EU RISE Project has shown that even five years after SCI, severe atrophic myofibers with a peculiar cluster reorganization of myonuclei are present in human muscles and respond to h-bFES. CONCLUSIONS: Human myofibers survive permanent denervation longer than generally accepted and they respond to h-bFES beyond the stage of simple atrophy. Furthermore, long-term denervation/reinnervation events occur in elderly people and are part of the mechanisms responsible for muscle aging and again h-bFES was beneficial in delaying aging decay.

Recovery from muscle weakness by exercise and FES: lessons from Masters, active or sedentary seniors and SCI patients.

Many factors contribute to the decline of skeletal muscle that occurs as we age. This is a reality that we may combat, but not prevent because it is written into our genome. The series of records from World Master Athletes reveals that skeletal muscle power begins to decline at the age of 30 years and continues, almost linearly, to zero at the age of 110 years. Here we discuss evidence that denervation contributes to the atrophy and slowness of aged muscle. We compared muscle from lifelong active seniors to that of sedentary elderly people and found that the sportsmen have more muscle bulk and slow fiber type groupings, providing evidence that physical activity maintains slow motoneurons which reinnervate muscle fibers. Further, accelerated muscle atrophy/degeneration occurs with irreversible Conus and Cauda Equina syndrome, a spinal cord injury in which the human leg muscles may be permanently disconnected from the nervous system with complete loss of muscle fibers within 5-8 years. We used histological morphometry and Muscle Color Computed Tomography to evaluate muscle from these peculiar persons and reveal that contraction produced by home-based Functional Electrical Stimulation (h-bFES) recovers muscle size and function which is reversed if h-bFES is discontinued. FES also reverses muscle atrophy in sedentary seniors and modulates mitochondria in horse muscles. All together these observations indicate that FES modifies muscle fibers by increasing contractions per day. Thus, FES should be considered in critical care units, rehabilitation centers and nursing facilities when patients are unable or reluctant to exercise.

Persistent Muscle Fiber Regeneration in Long Term Denervation. Past, Present, Future.

Despite the ravages of long term denervation there is structural and ultrastructural evidence for survival of muscle fibers in mammals, with some fibers surviving at least ten months in rodents and 3-6 years in humans. Further, in rodents there is evidence that muscle fibers may regenerate even after repeated damage in the absence of the nerve, and that this potential is maintained for several months after denervation. While in animal models permanently denervated muscle sooner or later loses the ability to contract, the muscles may maintain their size and ability to function if electrically stimulated soon after denervation. Whether in mammals, humans included, this is a result of persistent de novo formation of muscle fibers is an open issue we would like to explore in this review. During the past decade, we have studied muscle biopsies from the quadriceps muscle of Spinal Cord Injury (SCI) patients suffering with Conus and Cauda Equina syndrome, a condition that fully and irreversibly disconnects skeletal muscle fibers from their damaged innervating motor neurons. We have demonstrated that human denervated muscle fibers survive years of denervation and can be rescued from severe atrophy by home-based Functional Electrical Stimulation (h-bFES). Using immunohistochemistry with both non-stimulated and the h-bFES stimulated human muscle biopsies, we have observed the persistent presence of muscle fibers which are positive to labeling by an antibody which specifically recognizes the embryonic myosin heavy chain (MHCemb). Relative to the total number of fibers present, only a small percentage of these MHCemb positive fibers are detected, suggesting that they are regenerating muscle fibers and not pre-existing myofibers re-expressing embryonic isoforms. Although embryonic isoforms of acetylcholine receptors are known to be re-expressed and to spread from the end-plate to the sarcolemma of muscle fibers in early phases of muscle denervation, we suggest that the MHCemb positive muscle fibers we observe result from the activation, proliferation and fusion of satellite cells, the myogenic precursors present under the basal lamina of the muscle fibers. Using morphological features and molecular biomarkers, we show that severely atrophic muscle fibers, with a peculiar cluster reorganization of myonuclei, are present in rodent muscle seven-months after neurectomy and in human muscles 30-months after complete Conus-Cauda Equina Syndrome and that these are structurally distinct from early myotubes. Beyond reviewing evidence from rodent and human studies, we add some ultrastructural evidence of muscle fiber regeneration in long-term denervated human muscles and discuss the options to substantially increase the regenerative potential of severely denervated human muscles not having been treated with h-bFES. Some of the mandatory procedures, are ready to be translated from animal experiments to clinical studies to meet the needs of persons with long-term irreversible muscle denervation. An European Project, the trial Rise4EU (Rise for You, a personalized treatment for recovery of function of denervated muscle in long-term stable SCI) will hopefully follow.

Biology of Muscle Atrophy and of its Recovery by FES in Aging and Mobility Impairments: Roots and By-Products.

There is something in our genome that dictates life expectancy and there is nothing that can be done to avoid this; indeed, there is not yet any record of a person who has cheated death. Our physical prowess can vacillate substantially in our lifetime according to our activity levels and nutritional status and we may fight aging, but we will inevitably lose. We have presented strong evidence that the atrophy which accompanies aging is to some extent caused by loss of innervation. We compared muscle biopsies of sedentary seniors to those of life long active seniors, and show that these groups indeed have a different distribution of muscle fiber diameter and fiber type. The senior sportsmen have many more slow fiber-type groupings than the sedentary people which provides strong evidence of denervation-reinnervation events in muscle fibers. It appears that activity maintains the motoneurons and the muscle fibers. Premature or accelerated aging of muscle may occur as the result of many chronic diseases. One extreme case is provided by irreversible damage of the Conus and Cauda Equina, a spinal cord injury (SCI) sequela in which the human leg muscles may be completely and permanently disconnected from the nervous system with the almost complete disappearance of muscle fibers within 3-5 years from SCI. In cases of this extreme example of muscle degeneration, we have used 2D Muscle Color CT to gather data supporting the idea that electrical stimulation of denervated muscles can retain and even regain muscle. We show here that, if people are compliant, atrophy can be reversed. A further example of activity-related muscle adaptation is provided by the fact that mitochondrial distribution and density are significantly changed by functional electrical stimulation in horse muscle biopsies relative to those not receiving treatment. All together, the data indicate that FES is a good way to modify behaviors of muscle fibers by increasing the contraction load per day. Indeed, it should be possible to defer the muscle decline that occurs in aging people and in those who have become unable to participate in physical activities. Thus, FES should be considered for use in rehabilitation centers, nursing facilities and in critical care units when patients are completely inactive even for short periods of time.

Long-term high-level exercise promotes muscle reinnervation with age.

The histologic features of aging muscle suggest that denervation contributes to atrophy, that immobility accelerates the process, and that routine exercise may protect against loss of motor units and muscle tissue. Here, we compared muscle biopsies from sedentary and physically active seniors and found that seniors with a long history of high-level recreational activity up to the time of muscle biopsy had 1) lower loss of muscle strength versus young men (32% loss in physically active vs 51% loss in sedentary seniors); 2) fewer small angulated (denervated) myofibers; 3) a higher percentage of fiber-type groups (reinnervated muscle fibers) that were almost exclusive of the slow type; and 4) sparse normal-size muscle fibers coexpressing fast and slow myosin heavy chains, which is not compatible with exercise-driven muscle-type transformation. The biopsies from the old physically active seniors varied from sparse fiber-type groupings to almost fully transformed muscle, suggesting that coexpressing fibers appear to fill gaps. Altogether, the data show that long-term physical activity promotes reinnervation of muscle fibers and suggest that decades of high-level exercise allow the body to adapt to age-related denervation by saving otherwise lost muscle fibers through selective recruitment to slow motor units. These effects on size and structure of myofibers may delay functional decline in late aging.