ORIGINAL RESEARCH published: 16 December 2020 doi: 10.3389/fneur.2020.613446 Intensive Teenage Activity Is Associated With Greater Muscle Hyperintensity on T1W Magnetic Resonance Imaging in Adults With Dysferlinopathy Ursula Moore 1 , Marni Jacobs 2,3 , Roberto Fernandez-Torron 1,4 , Jaume LLauger Rossello 5 , Fiona E. Smith 6 , Meredith James 1 , Anna Mayhew 1 , Laura Rufibach 7 , Pierre G. Carlier 8 , Andrew M. Blamire 6 , John W. Day 9 , Kristi J. Jones 10 , Diana X. Bharucha-Goebel 11,12 , Emmanuelle Salort-Campana 13 , Alan Pestronk 14 , Maggie C. Walter 15 , Edited by: Carmen Paradas 16,17 , Tanya Stojkovic 18 , Madoka Mori-Yoshimura 19 , Elena Bravver 20† , Xin-Ming Shen, Elena Pegoraro 21 , Jerry R. Mendell 22 , on behalf of The Jain COS Consortium, Mayo Clinic, United States Kate Bushby 1 , Volker Straub 1 and Jordi Diaz-Manera 1,23,24* Reviewed by: 1 Anna Pichiecchio, The John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University, Neurological Institute Foundation Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom, 2 Division of Biostatistics and Study Casimiro Mondino (IRCCS), Italy Methodology, Center for Translational Science, Children’s National Health System, Washington, DC, United States, 3 Teerin Liewluck, Pediatrics, Epidemiology and Biostatistics, George Washington University, Washington, DC, United States, 4 Neuromuscular Mayo Clinic, United States Area, Biodonostia Health Research Institute, Neurology Service, Donostia University Hospital, Donostia-San Sebastian, Spain, 5 Radiology Department, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain, *Correspondence: 6 Magnetic Resonance Centre, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, Jordi Diaz-Manera United Kingdom, 7 Jain Foundation, Newcastle upon Tyne, Seattle, WA, United States, 8 Université Paris-Saclay, CEA, DRF, jordi.diaz-manera@newcastle.ac.uk Service Hospitalier Frederic Joliot, Orsay, France, 9 Department of Neurology and Neurological Sciences, Stanford University † deceased School of Medicine, Stanford, CA, United States, 10 The Children’s Hospital at Westmead, The University of Sydney, Sydney, NSW, Australia, 11 Department of Neurology Children’s National Health System, Washington, DC, United States, 12 National Institutes of Health (NINDS), Bethesda, MD, United States, 13 Service des maladies neuromusculaire et de la SLA, Hôpital de Specialty section: La Timone, Marseille, France, 14 Department of Neurology Washington University School of Medicine, St. Louis, MO, This article was submitted to United States, 15 Department of Neurology, Friedrich-Baur-Institute, Ludwig-Maximilians-University of Munich, Munich, Neuromuscular Diseases, Germany, 16 Center for Biomedical Network Research on Eurodegenerative Diseases, Instituto de Salud Carlos III, Madrid, a section of the journal Spain, 17 Neuromuscular Unit, Department of Neurology, Hospital U. Virgen del Rocío/Instituto de Biomedicina de Sevilla, Frontiers in Neurology Sevilla, Spain, 18 Centre de référence des maladies neuromusculaires, Institut de Myologie, AP-HP, Sorbonne Université, Received: 02 October 2020 Hôpital Pitié-Salpêtrière, Paris, France, 19 Department of Neurology, National Center Hospital, National Center of Neurology Accepted: 23 November 2020 and Psychiatry Tokyo, Tokyo, Japan, 20 Carolinas Neuromuscular/ALS-MDA Center, Neuroscience Institute, Carolinas Published: 16 December 2020 HealthCare System, Charlotte, NC, United States, 21 Department of Neuroscience, University of Padova, Padova, Italy, 22 The Abigail Wexner Research Institute at Nationwide Children’s Hospital, Columbus, OH, United States, 23 Neuromuscular Citation: disorders Unit, Department of Neurology, Hospital de la Santa Creu I Sant Pau, Barcelona, Spain, 24 Centro de Investigación Moore U, Jacobs M, Biomédica en Red en Enfermedades Raras (CIBERER), Valencia, Spain Fernandez-Torron R, LLauger Rossello J, Smith FE, James M, Mayhew A, Rufibach L, Carlier PG, Blamire AM, Practice of sports during childhood or adolescence correlates with an earlier onset and Day JW, Jones KJ, Bharucha-Goebel DX, Salort-Campana E, Pestronk A, more rapidly progressing phenotype in dysferlinopathies. To determine if this correlation Walter MC, Paradas C, Stojkovic T, relates to greater muscle pathology that persists into adulthood, we investigated the Mori-Yoshimura M, Bravver E, Pegoraro E, Mendell JR, Bushby K, effect of exercise on the degree of muscle fatty replacement measured using muscle Straub V and Diaz-Manera J (2020) MRI. We reviewed pelvic, thigh and leg T1W MRI scans from 160 patients with genetically Intensive Teenage Activity Is confirmed dysferlinopathy from the Jain Foundation International clinical outcomes Associated With Greater Muscle Hyperintensity on T1W Magnetic study in dysferlinopathy. Two independent assessors used the Lamminen-Mercuri visual Resonance Imaging in Adults With scale to score degree of fat replacement in each muscle. Exercise intensity for each Dysferlinopathy. Front. Neurol. 11:613446. individual was defined as no activity, minimal, moderate, or intensive activity by using doi: 10.3389/fneur.2020.613446 metabolic equivalents and patient reported frequency of sports undertaken between Frontiers in Neurology | www.frontiersin.org 1 December 2020 | Volume 11 | Article 613446 Moore et al. Dysferlinopathy: Exercise Effect on MRI the ages of 10 and 18. We used ANCOVA and linear modeling to compare the mean Lamminen-Mercuri score for the pelvis, thigh, and leg between exercise groups, controlling for age at assessment and symptom duration. Intensive exercisers showed greater fatty replacement in the muscles of the pelvis than moderate exercisers, but no significant differences of the thigh or leg. Within the pelvis, Psoas was the muscle most strongly associated with this exercise effect. In patients with a short symptom duration of <15 years there was a trend toward greater fatty replacement in the muscles of the thigh. These findings define key muscles involved in the exercise-phenotype effect that has previously been observed only clinically in dysferlinopathy and support recommendations that pre-symptomatic patients should avoid very intensive exercise. Keywords: dysferlinopathy, Magnetic Resonace Imaging (MRI), Miyoshi myopathy, LGMDR2, limb girdle muscle dystrophy, exercise INTRODUCTION of muscle involvement in dysferlinopathy, with certain muscles consistently demonstrating greater, or earlier, fat replacement Dysferlinopathy is an autosomal recessively inherited form of than others (9). muscular dystrophy caused by mutations in the DYSF gene. In this study we use T1W images from this previously It usually presents in early adulthood and is characterized by described cohort, in combination with questionnaire derived progressive weakness and wasting of skeletal muscles (1). information about pre-symptomatic activity levels to objectively Unlike many other forms of muscular dystrophy, patients assess the impact of teenage exercise on muscle fat replacement. with dysferlinopathy often report performing a large amount We review if this supports the patient reported earlier onset of physical activity as children and young adults, before their and more rapid loss of ambulation in intensive exercisers, symptoms first present (2, 3). This intensive exercise appears to if exercise has differential effects in muscle, such that some be detrimental and we have previously demonstrated that higher muscles are more impacted than others and if conclusions can levels of exercise before symptom onset is associated with both be reached about the types of exercise that may be detrimental earlier patient reported symptom onset and earlier subsequent in dysferlinopathy. wheelchair requirement (4). The association of exercise and disease progression in dysferlinopathy has been investigated in mouse models, with METHODS interesting results. Eccentric muscle contractions (such as running) cause more rapid progression of muscular dystrophy Study Subjects pathology and greater functional weakness, while concentric This investigation reviews MRI imaging from the Jain muscle contraction (such as swimming) appeared to be protective Foundation’s international longitudinal Clinical Outcomes against both general disease progression and in mitigating Study for Dysferlinopathy (COS). This study included 201 the myofiber damage caused by subsequent eccentric muscle patients with genetically confirmed dysferlinopathy from 15 sites contraction (5, 6). This finding clearly has implications for internationally (10). This study received ethical approval in all patients in terms of the type or intensity of exercise that should participating countries. MRI was not mandatory for inclusion be recommended. However, murine models of dysferlinopathy in the study and some sites could only perform lower limb MRI are not particularly good mimics of the human phenotype, being (not including the pelvis). Overall, 182 patients had a baseline much less severe, and it is not certain if these findings can be MRI, including 84 patients with a whole body scan and 98 generalized (6). In humans with dysferlinopathy, pathological patients with only lower limb scans. Imaging from 22 patients differences depending on exercise type or intensity have not been did not produce adequate images for visual scoring to be applied assessed and it is not clear if early influences of exercise would (see below) and were excluded. This investigation therefore remain detectable after many years of symptomatic disease. reviews MRI imaging from 160 patients. Magnetic resonance imaging (MRI) can be used to non- This report uses the questionnaire based exercise information invasively and objectively measure increases in intramuscular fat, (Supplementary Material) and the MRI images collected acting as marker for muscle pathology. T1W sequences clearly from the patients screening and baseline visits, respectively. delineate fat and muscle and are used to produce images for These visits also involved medical interview and examination, visual inspection to determine the degree of the muscle that has physiotherapy assessment, blood sampling, cardiac, and been replaced by fat. This method is used to determine both the respiratory investigations. A cross-sectional description of the pattern and severity of muscle involvement in neuromuscular baseline cohort demographic and functional information (10), disorders, and is widely used to support genetic diagnosis (7, 8). and pattern of muscle involvement on T1W MRI at baseline (9) T1W MRI has been used to characterize a distinctive pattern have been previously published. Frontiers in Neurology | www.frontiersin.org 2 December 2020 | Volume 11 | Article 613446 Moore et al. Dysferlinopathy: Exercise Effect on MRI Semiquantitative MRI Assessment (Supplementary Material). Exercise was coded based on the Semiquantitative assessments of MRIs were performed by maximum patient reported frequency between the age of a blinded neurologist (RF-T) and radiologist (JL), who 10 and 18 years, and the metabolic equivalent (MET) of independently evaluated axial T1-weighted sequences with the the activities described, as previously reported (4). Group 0 Lamminen-Mercuri visual scale, with an inter-rater agreement reported no physical activity, group 1 reported vigorous activity kappa of 0.93 (95% CI 0.91–0.96), as previously reported (9). occasionally/monthly, or moderate activity once a week, group For the 4% of scans where observers scores did not match, 2 reported moderate activity multiple times a week or vigorous observers reviewed the muscles together and agreed a final score activity once weekly, and group 3 reported vigorous activity (9). All 160 patients had complete Lamminen-Mercuri score multiple times per week. results for the lower leg muscles—Tibialis anterior, extensor digitorum, peroneus longus, peroneus brevis, gastrocnemius Statistical Analysis medialis and lateralis, soleus, flexor digitorum, and tibialis Age at MRI and symptom duration were not normally posterior. Complete imaging of adductors was not included in distributed and so were compared in a stepwise fashion between some patients, leaving 106 of these 160 patients who also had exercise groups using the Wilcoxon-Mann-Whitney test for non- a complete set of Lamminen-Mercuri scores for thigh muscles parametric unpaired samples (i.e., group 0 vs. group 1, group 0 (Adductor brevis, longus an major, quadratus femoris, rectus vs. group 2 and so forth for comparison between all groups). femoris, vastus lateralis, vastus intermedius and vastus medialis, A mean Lamminen-Mercuri score for the distal leg was sartorius, gracilis, semimembranosus, semitendinosus, long, and calculated from the sum of scores of each individual muscle (n = short head of biceps femoris). Full pelvic muscle Lamminen- 160). This was repeated to generate a mean Lamminen-Mercuri Mercuri scores were available for 67 of the 160. Pelvic muscles score for the thigh (n = 106) and the pelvis (n = 67). Muscles were psoas, pectineus, piriformis, iliacus, gluteus medius, gluteus included are listed above. maximus, gluteus minor, tensor fasciae latae, obturator internus, To determine if there was any difference in Lamminen- and obturator externus. Mercuri scores between exercise groups, mean Lamminen- Mercuri scores of the a. leg, b. thigh and c. pelvis were compared Exercise Scoring between exercise groups using type III ANCOVA, using the At the screening visit, patients reported the type and frequency “Anova” function from the package “car” in the programme R. of all regular activities performed as children and teenagers Age at MRI and symptom duration were assessed as covariates. TABLE 1 | Table showing demographic factors of patients in each exercise group at baseline. Exercise group 0 1 2 3 Distal leg MRI (n = 160) Number of patients 39 17 54 50 Male (%) 14 (36) 9 (53) 30 (56) 28 (56) Symptom onset age in years—median (range)* 25.00 (12–48) 17.00 (12–60) 18.00 (10–41) 18.00 (12.5–40) Symptom duration in years—median (range)** 20.00 (4–41) 11.00 (2–42) 12.50 (2–38) 17.00 (3–51) Age at assessment in years—median (range)*** 47.00 (22–86) 35.00 (15–71) 31.50 (15–57) 37.50 (22–67) Thigh MRI in (n = 106) Number of patients 25 12 40 29 Male (%) 9 (36) 6 (50) 23 (58) 17 (59) Symptom onset age in years – median (range)(*) 25.00 (12–48) 18.5 (12–60) 18.00 (10–41) 17.5 (13–28) Symptom duration in years—median (range) 21(4–41) 18.5 (3–42) 13.00 (2–38) 16.5 (3–51) Age at assessment in years—median (range)**** 47.00 (32–86) 37.5 (15–71) 30.00 (15–57) 37.00 (22–64) Pelvic MRI (n = 67) Number of patients 11 6 28 22 Male (%) 2 (18) 3 (50) 13 (46) 12 (55) Symptom onset age in years—median (range)* 26.00 (14–39) 16.00 (12–60) 18.00 (12–41) 17.50 (13–27) Symptom duration in years—median (range)** 16.00 (10–41) 14.00 (3–26) 13.00 (4–23) 19.00 (6–51) Age at assessment in years—median (range)*** 47.00 (32–66) 32.50 (15–71) 32.500 (19–57) 39.00 (22–64) MRI: T1 weighted magnetic resonance imaging. *Median age of symptom onset significantly higher in group 0 compared to group 1, 2, and 3. **Median disease duration significantly shorter in group 2 than in group 0 or group 3. ***Group 0 are significantly older than group 3 who are, in turn, significantly older than group 2. ****Group 0 is significantly older than group 2. Frontiers in Neurology | www.frontiersin.org 3 December 2020 | Volume 11 | Article 613446 Moore et al. Dysferlinopathy: Exercise Effect on MRI Firstly, age was considered as a covariate to determine if patients ANCOVA of the Lamminen-Mercuri scores of the individual in a particular exercise group at any given age had a different muscles within that group and compared in the same way as for Lamminen-Mercuri score than those in another group. Secondly, the muscle groups. symptom duration and age were combined as covariates to In order to review if results differed in a subset of patients with determine if fat replacement on MRI progressed more rapidly a shorter disease duration, we repeated this analysis of pelvic, (from the onset of symptoms) in one exercise group than another. thigh and leg muscle groups in patients with symptoms for <15 Post-hoc analysis of significant (p < 0.05) ANCOVA results was years at the time of assessment. completed using the “lsmeans()” function, from the package Post-hoc review of p-values using Bonferonni correction for “lsmeans.” This was to identify which exercise groups were multiple comparisons was performed. No power calculations significantly different from each other, and thus causing the were conducted to determine group size as data was from an significant ANCOVA result. existing study. For visual representation of the exercise dependent effects, linear modeling was used. A linear model of Lamminen- RESULTS Mercuri score was generated with age and exercise group as covariates. This allowed calculation of the mean model predicted Demographics Lamminen-Mercuri score for each exercise group as if all Patient reported age of symptom onset was later in the inactive patients were of the same age (39 years—the mean age of group 0 than in all of the other exercise groups (Table 1). Patients the cohort). This was repeated with disease duration as an in group 0 were significantly older at the time of assessment than additional covariate (along with age) to produce model predicted those in the extremely active group 3, who were in turn older Lamminen-Mercuri scores as if all patients had had the same than those in group 2 (p < 0.05) (Table 1). Overall, patients in disease duration (17 years—the mean disease duration of the the moderately active group 2 had a shorter median symptom cohort) and age. duration at the time of assessment than those in group 0 or in Muscle groups showing significant differences between group 3 (p < 0.05). Number of patients in group 1 was small (17 exercise groups were then further reviewed with additional patients in distal leg MRI group) with variable age and disease FIGURE 1 | ANCOVA predicted Lamminen-Mercuri scores for each exercise group. The top row (A) shows predicted score in each exercise group (0, 1, 2, or 3) adjusted for age—i.e., as though all patients were the cohort mean age of 39 years. The bottom row (B) shows predicted score in each exercise group (0, 1, 2, or 3) adjusted for disease duration and age—i.e., as though all patients had an age of 39 years and the cohort mean symptom duration of 17 years. Bars show the 95% confidence interval. Red text denotes groups showing significant differences on ANCOVA (p < 0.005). Frontiers in Neurology | www.frontiersin.org 4 December 2020 | Volume 11 | Article 613446 Moore et al. Dysferlinopathy: Exercise Effect on MRI FIGURE 2 | ANCOVA predicted Lamminen-Mercuri scores of the pelvis muscles, adjusted for age. Bars show the 95% confidence interval. Red text denotes groups showing significant differences on ANCOVA (p < 0.005). Patients are split into exercise groups 0, 1, 2, or 3. duration, which was not significantly different from those in multiple comparisons, this only remained significant for psoas other exercise groups. (p = 0.0004), which showed a significantly higher predicted In the groups of patients who had pelvic or thigh imaging, the Lamminen-Mercuri score in exercise group 3 compared to median age of onset, age at assessment and symptom duration in groups 0 (p = 0.03), 1 (p = 0.0032), and 2 (p = 0.007). each exercise group did not differ significantly from that in the In the smaller subset of patients (n = 73) with symptoms for larger cohort. <15 years, there was a trend toward greater Lamminen-Mercuri score in groups 3 than 2 and in group 2 than 1 in the pelvis Age Adjusted Mercuri Score and thigh. However, there was no longer a significant difference There were significant differences between exercise groups in the in pelvic muscles by exercise group and although there was a mean predicted Lamminen-Mercuri score of the pelvic muscles difference between groups in the thigh muscles (p = 0.044), (p ≤ 0.0001), when controlling for age as a covariate. This was this did not remain after correction for multiple comparisons driven by a significantly higher predicted Lamminen-Mercuri (Figure 3). score in exercise group 3, compared to group 1 (3 vs. 1, p = 0.0018) and group 2 (3 vs. 2, p = 0.0002). There was no significant Symptom Duration and Age Adjusted difference between group 0 and any of the other exercise groups. Mercuri Score There was no difference in mean predicted Lamminen-Mercuri In ANCOVA of Lamminen-Mercuri score with symptom score of thigh or leg muscles between groups (Figure 1). duration, age and exercise group as covariates, symptom duration Modeling using age and teenage exercise level could account was always a stronger predictor of Lamminen-Mercuri score than for one third of the observed variability in Lamminen-Mercuri age and age was not an independent predictor of Lamminen- score in the whole leg (adjusted R2 = 0.33), while using age alone Mercuri score. produced an R2 value of 0.14. Symptom duration was a strong predictor of Lamminen- The individual muscles in the pelvis showing a significant Mercuri score and modeling using symptom duration alone difference (p < 0.05) in age normalized Lamminen-Mercuri score accounted for 38% of the variation in Lamminen-Mercuri score between exercise groups were psoas, piriformis, pectineus, iliacus, (adjusted R2 = 0.38) in the whole leg. Adding exercise group to and gluteus medius (Figure 2). However, after correction for the model improved the adjusted R2 value to 0.47, which was not Frontiers in Neurology | www.frontiersin.org 5 December 2020 | Volume 11 | Article 613446 Moore et al. Dysferlinopathy: Exercise Effect on MRI FIGURE 3 | ANCOVA predicted Lamminen-Mercuri scores for each exercise group in those with <15 years of symptoms. The top row (A) shows predicted score in each exercise group (0, 1, 2, or 3) adjusted for age—i.e., as though all patients were the cohort mean age of 31 years. The bottom row (B) shows predicted score in each exercise group (0, 1, 2, or 3) adjusted for disease duration and age—i.e., as though all patients had an age of 31 years and the cohort mean symptom duration of 8 years. Bars show the 95% confidence interval. Red text denotes groups showing significant differences on ANCOVA (p < 0.005). bettered by the further addition of age to the model (adjusted R2 after their teenage years. Psoas, pectineus, and piriformis were = 0.47). When accounting for symptom duration and age, there the most differentially affected muscles. Patients who performed remained significant differences in mean predicted Lamminen- intensive exercise as teenagers generally demonstrated a higher Mercuri score of the pelvic muscles (p = 0.0015) between exercise (worse) Lamminen-Mercuri score at a given age and disease groups. Again, this was driven by a significantly higher predicted duration, suggesting a more rapid progression of fat replacement Lamminen-Mercuri score in exercise group 3, compared to group from symptom onset. 2 (3 vs. 2, p = 0.0029) and group 1 (3 vs. 1, p = 0.0148). There was We did not demonstrate any association between exercise no significant difference between group 0 and any of the other group and the muscle groups of the thigh or distal leg in exercise groups in the pelvis. There were no differences between the overall group, but there was a trend toward a higher exercise groups in thigh or leg muscle groups (Figure 1). Lamminen-Mercuri score in the thigh muscle of intensive The muscle in the pelvis showing the greatest difference in exercisers with <15 years symptom duration. The thigh and age and symptom duration adjusted Lamminen-Mercuri score leg muscles generally have a higher Lamminen-Mercuri score between exercise groups remained psoas (p = 0.016) (Figure 4, in this cohort than the muscles of pelvis (9), suggesting earlier example MRI images in Figure 5). However, differences between or more significant involvement of these muscles in the disease groups in psoas Lamminen-Mercuri score were not significant on process. It may be that no difference was demonstrated between ANCOVA after correction for multiple comparisons. exercise groups in the thigh and distal leg overall because too In the smaller subset of patients with symptoms for <15 years, many patients are already at a stage where these muscles are there was no longer a significant difference between exercise severely affected, essentially reaching a ceiling of the maximum groups in any of the muscle groups. Lamminen-Mercuri score of 4 relatively early in the disease process. The finding of potential differences in the thigh muscles DISCUSSION in less advanced disease suggests that there may have been differences in all muscles at some point in progression of We have demonstrated an association between intensive teenage the disease. exercise and a subsequent more severely affected MRI appearance In earlier work, we showed that symptom onset and age of part of pelvic musculature in adult patients with dysferlinopathy, long and full time wheelchair use is significantly earlier in intensive Frontiers in Neurology | www.frontiersin.org 6 December 2020 | Volume 11 | Article 613446 Moore et al. Dysferlinopathy: Exercise Effect on MRI FIGURE 4 | ANCOVA predicted Lamminen-Mercuri scores of the pelvis muscles, adjusted for age, and disease duration. Bars show the 95% confidence interval. Red text denotes groups showing significant differences on ANCOVA (p < 0.005). Patients are split into exercise groups 0, 1, 2, or 3. FIGURE 5 | T1W MRI images from age and duration matched patients. T1W MRI images of the lower abdomen and pelvisfor a representative patient from each exercise group (0, 1, 2, and 3) of a similar age and symptom duration. GMa, gluteus maximus; GMe, gluteus medius; GMi, gluteus minimus; I, Iliacus. Representative patients from groups 0, 2, and 3 were all aged 36 years with symptom duration 18 or 19 years at the time of the MRI. Group 1 patient was aged 33 years with a symptom duration of 21 years. than moderate exercisers (4). While this MRI study adds objective this may translate to differences in Lamminen-Mercuri score evidence to this observation, we did not observe the previously between exercise group 0, group 2, and group 3. However, this described “dose” type of association with exercise—with non was not seen and the key differences in Lamminen-Mercuri score and very light exercisers (groups 0 and 1) having a significantly were between exercise groups 2 and 3 and not group 0. There later age of onset and wheelchair requirement than those in are several possible explanations for this. Firstly, this may be group 2. We had anticipated that when investigating the MRI, related to the possible ceiling effect of the Lamminen-Mercuri Frontiers in Neurology | www.frontiersin.org 7 December 2020 | Volume 11 | Article 613446 Moore et al. Dysferlinopathy: Exercise Effect on MRI score, as patients in group 0 were significantly older and had had use to intensive teenage exercise. For patients who receive symptoms for significantly longer than patients in group 2 and a diagnosis before symptom onset, such as through family 3, making them more likely to have reached this plateau. It is screening or detection of high CK, this evidence would support a also possible that, the more time that intervenes between teenage recommendation to avoid very intensive exercise regimens before years and subsequent assessment the less marked the effect of symptom onset, while maintaining a healthy lifestyle. exercise on imaging results—this would again dilute any effect in the older group 0. Finally, while the majority of non-exercisers had a relatively late onset of symptoms, some had a younger DATA AVAILABILITY STATEMENT onset and probably did not exercise precisely because they had already started to experience symptoms. The muscle MRI of these The raw data supporting the conclusions of this article will more severely affected patients may “skew” the results of the be made available on reasonable request to the study steering non-exercising group 0. group. Requests should be directed to Professor Volker Straub The method used here to quantify the “amount” of exercise at volker.straub@newcastle.ac.uk. performed used the relative metabolic equivalents of the sports performed, giving an estimate of the intensity of the exercise. However, research in mice suggests that it may be ETHICS STATEMENT the type of muscle contraction, rather than the metabolic The studies involving human participants were reviewed and cost, which determines the effect on dysferlin deficient muscle approved by local ethics committees in each country involved (5, 6). Unfortunately we were not able to assess this here in the study: Comité Etico de investigacion con médicamentos because, as anticipated in an observational study, none of our de la Fundacio de Gestio Sanitaria de la Santa Creu I participants had performed exclusively concentric exercise (such Sant Pau, Barcelona, Spain; The Carolinas HealthCare System as swimming) without also reporting frequent eccentric sports Institutional Review Board Federal-Wide Assurance, Charlotte, (such as running). United States; IRB at Nationwide Children’s Hospital, Columbus, We have identified specific muscles in the pelvis that were United States; Le Comité de Protection des Personnes Sud- more affected in intensive exercisers in this cohort. This raises Méditerranée, Marseille and Paris, France; Ethikkomission bei the question of why these particular muscles are affected while de LMU Munchen, Munich, Germany; Stanford University IRB, others are not. This may in part be due to differences only being Panel on Human Subjects, Panel 7, Stanford, United States; observable in less affected muscle, as discussed above. However, The Washington University in St. Louis Institutional Review there were some muscles which are not extensively involved Board, St Louis, United States; The Medical Ethics Committee across exercise groups (such as gluteus maximum) and yet still of the NCNP, Tokyo, Japan; Children’s National Medical do not demonstrate differential involvement. It seems reasonable Center Institutional Review Board (Children’s National IRB), that sports that preferentially use specific muscles could affect Washing DC, United States; Newcastle and North Tyneside these muscles more than others, and as many intensive sports 2 medical ethics committee, Newcastle, United Kingdom; El involve a significant amount of running, intensive exercisers may comité de Etica de a investigacion de Centro H.U Virgen see proportionally greater damage in muscles involved heavily in del Rocio de Sevilla, Seville, Spain; REGIONE VENETO running—such as psoas (11, 12). We did attempt to review this in AZIENDA OSPEDALIERA DI PADOVA Comitato Etico per la our cohort, comparing Lamminen-Mercuri scores for individual Sperimentazione, Padova, Italy; Children’s Hospitals Network muscles between patients who reported different activities (e.g., Human Research Ethics Committee, Sydney, Australia; North predominantly running vs. predominantly swimming). We did East—Newcastle and North Tyneside Health Research Authority not find differential Lamminen-Mercuri scores between the most research ethics committee, Newcastle, United Kingdom. The frequently performed activities, however this analysis is likely patients/participants provided their written informed consent to significantly confounded by the multiple activities performed by participate in this study. each patient. Muscle MRI offers the possibility to analyse the impact of exercise in muscle structure. In our opinion, the results of AUTHOR CONTRIBUTIONS this study should encourage further research in muscle MRI biomarkers in dysferlinopathy patients performing different UM contributed to data acquisition, conception and study types of exercise. Muscle MRI sequences that could be helpful design, analysis of data, and preparation of the manuscript. include but are not limited to STIR, T2 imaging, sodium MRI, MaJ contributed to review of statistical analysis and drafting. and P31-spectroscopy (13–15). All of these previous imaging RF-T, JL, FS, MeJ, AM, LR, PC, AB, JD, KJ, DB-G, ES-C, sequences have identified early changes in muscle structure, that AP, MW, CP, TS, MM-Y, EB, EP, JM, and KB contributed in the case of dysferlinopathy patients, could help to elucidate to acquisition and analysis of data and drafting. VS which program of exercise is less harmful for the skeletal muscles. contributed to conception and study design, acquisition This analysis confirms that T1W imaging demonstrates and analysis of data, and drafting. JD-M contributed to more severe fat replacement in muscles of patients with conception and study design, acquisition and analysis of dysferlinopathy who performed intensive, rather than moderate, data, drafting, and final sign of corresponding author. exercise as teenagers. This adds pathological evidence to the All authors contributed to the article and approved the previous report linking symptom onset and earlier wheelchair submitted version. Frontiers in Neurology | www.frontiersin.org 8 December 2020 | Volume 11 | Article 613446 Moore et al. Dysferlinopathy: Exercise Effect on MRI FUNDING development, management, and analysis of this Study. The Jain Foundation, based in Seattle, USA, is entirely focused on The estimated $4 million USD needed to fund this study LGMD2B/dysferlinopathy/Miyoshi Myopathy. The foundation was provided by the Jain Foundation. VS was supported does not solicit funding from patients, but instead funds research by an MRC strategic award to establish an International and clinical studies worldwide with the goal of finding treatments Centre for Genomic Medicine in Neuromuscular Diseases for dysferlinopathy. Please visit www.jain-foundation.org for (ICGNMD) MR/S005021/1. more information about the foundation and if you are a patient suffering from dysferlinopathy, please consider enrolling into their interactive dysferlinopathy registry that seeks to build ACKNOWLEDGMENTS a strong, engaged, and supportive community (patients@jain- foundation.org). This study has only been possible thanks to the international collaboration of several specialized centres promoted by the SUPPLEMENTARY MATERIAL Jain Foundation. The Jain COS consortium would like to thank the study participants and their families for their The Supplementary Material for this article can be found invaluable contribution and would also like to acknowledge online at: https://www.frontiersin.org/articles/10.3389/fneur. the ongoing support the Jain Foundation provides in the 2020.613446/full#supplementary-material REFERENCES 13. Carlier PG, Azzabou N, de Sousa PL, Hicks A, Boisserie J-M, Amadon A, et al. Skeletal muscle quantitative nuclear magnetic resonance imaging 1. Aoki M. Dysferlinopathy. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, follow-up of adult Pompe patients. J Inherited Metab Dis. (2015) 38:565–72. Bean LJH, Stephens K, et al., editors. GeneReviews( R ). Seattle, WA: University doi: 10.1007/s10545-015-9825-9 of Washington, Seattle (2004). 14. Reyngoudt H, Marty B, Caldas de Almeida Araújo E, Baudin PY, Le 2. Klinge L, Aboumousa A, Eagle M, Hudson J, Sarkozy A, Vita G, et al. Louër J, Boisserie JM, et al. 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Muscular strategy shift in human publication in this journal is cited, in accordance with accepted academic practice. running: dependence of running speed on hip and ankle muscle performance. No use, distribution or reproduction is permitted which does not comply with these J Exp Biol. (2012) 215:1944–56. doi: 10.1242/jeb.064527 terms. Frontiers in Neurology | www.frontiersin.org 9 December 2020 | Volume 11 | Article 613446