Surgical and long-term functional outcomes of patients with Duchenne muscular dystrophy following spinal deformity correction

BACKGROUND Life expectancy in patients with Duchenne muscular dystrophy(DMD)has improved due to advances in medical care.DMD patients develop progressive spinal deformity after loss of ambulatory function and onset of wheelchair dependence for mobility.There is limited published data on the effect of spinal deformity correction on long-term functional outcomes,quality of life(QoL),and satisfaction in DMD patients.AIM To investigate the long-term functional outcomes following spinal deformity correction in DMD patients.METHODS This was a retrospective cohort study from 2000-2022.Data was collected from hospital records and radiographs.At follow-up,patients completed the muscular dystrophy spine questionnaire(MDSQ).Statistical analysis was performed by linear regression analysis and ANOVA to analyse clinical and radiographic factors significantly associated with MDSQ scores.RESULTS Forty-three patients were included with mean age 14.4 years at surgery.Spinopelvic fusion was performed in 41.9%of patients.Mean surgical time was 352.1 min and mean blood loss was 36%of estimated total blood volume.Mean hospital stay was 14.1 d.Postoperative complications occurred in 25.6%of patients.Mean preoperative scoliosis was 58°,pelvic obliquity 16.4°,thoracic kyphosis 55.8°,lumbar lordosis 11.1°,coronal balance 3.8 cm,and sagittal balance+6.1 cm.Mean surgical correction of scoliosis was 79.2%and of pelvic obliquity was 80.8%.Mean follow-up was 10.9 years(range:2-22.5).Twenty-four patients had died at follow-up.Sixteen patients completed the MDSQ at mean age 25.4 years(range 15.2-37.3).Two patients were bed-ridden and 7 were on ventilatory support.Mean MDSQ total score was 38.1.All 16 patients were satisfied with the results of spinal surgery and would choose surgery again if offered.Most patients(87.5%)reported no severe back pain at follow-up.Factors significantly associated with functional outcomes(MDSQ total score)included greater duration of post-operative follow-up,age,scoliosis postoperatively,correction of scoliosis,increased lumbar lordosis postoperatively,and greater age at loss of independent ambulation.CONCLUSION Spinal deformity correction in DMD patients leads to positive long-term effects on QoL and high patient satisfaction.These results support spinal deformity correction to improve long-term QoL in DMD patients.

The resistive range of motion exercise training in Duchenne muscular dystrophy:a case study

Background:To determine the effectiveness of resistive range of motion exercises in improving muscle strength and functional abilities in Duchenne muscular dystrophy.The study was also aimed to determine if resistive range of motion exercises can slow down the progression of the disease.Methods:A seven-year-old male child was diagnosed with Duchenne muscle dystrophy presented to outpatient physiotherapy clinic.The patient was presented with difficulty in stair climbing,sitting up from the floor,fatigue,and muscle weakness specifically weakness in the proximal limb muscles.The progressive resistive range of motion training was implemented for four years to improve muscle strength and functional abilities.The medical research council grading scale,north ambulatory assessment scale,and creatine kinase were used to evaluate muscle strength,functional abilities,and creatine kinase levels.Results:The muscular strength and functional abilities did not improve after four years of exercise training.The creatine kinase levels were decreased over the period of four years.Conclusion:Resistive range of motion exercises are helpful in maintaining the muscular strength and functional abilities in Duchenne muscular dystrophy.

An Automated Deep Learning Based Muscular Dystrophy Detection and Classification Model

Muscular Dystrophy (MD) is a group of inherited muscular diseases that are commonly diagnosed with the help of techniques such asmuscle biopsy, clinical presentation, and Muscle Magnetic Resonance Imaging(MRI). Among these techniques, Muscle MRI recommends the diagnosis ofmuscular dystrophy through identification of the patterns that exist in musclefatty replacement. But the patterns overlap among various diseases whereasthere is a lack of knowledge prevalent with regards to disease-specific patterns.Therefore, artificial intelligence techniques can be used in the diagnosis ofmuscular dystrophies, which enables us to analyze, learn, and predict forthe future. In this scenario, the current research article presents an automated muscular dystrophy detection and classification model using SynergicDeep Learning (SDL) method with extreme Gradient Boosting (XGBoost),called SDL-XGBoost. SDL-XGBoost model has been proposed to act as anautomated deep learning (DL) model that examines the muscle MRI dataand diagnose muscular dystrophies. SDL-XGBoost model employs Kapur’sentropy based Region of Interest (RoI) for detection purposes. Besides, SDLbased feature extraction process is applied to derive a useful set of featurevectors. Finally, XGBoost model is employed as a classification approach todetermine proper class labels for muscle MRI data. The researcher conductedextensive set of simulations to showcase the superior performance of SDLXGBoost model. The obtained experimental values highlighted the supremacyof SDL-XGBoost model over other methods in terms of high accuracy being96.18% and 94.25% classification performance upon DMD and BMD respectively. Therefore, SDL-XGBoost model can help physicians in the diagnosis of muscular dystrophies by identifying the patterns of muscle fatty replacementin muscle MRI.

Adipose-derived stem cells enhance myogenic differentiation in the mdx mouse model of muscular dystrophy via paracrine signaling

Adipose-derived stem cells have been shown to promote peripheral nerve regeneration through the paracrine secretion of neurotrophic factors. However, it is unclear whether these cells can promote myogenic differentiation in muscular dystrophy. Adipose-derived stem cells （6 × 106） were injected into the gastrocnemius muscle of mdx mice at various sites. Dystrophin expression was found in the muscle fibers. Phosphorylation levels of Akt, mammalian target of rapamycin （mTOR）, eIF-4E binding protein 1 and $6 kinase 1 were increased, and the Akt/mTOR pathway was activated. Simultaneously, myogenin levels were increased, whereas cleaved caspase 3 and vimentin levels were decreased. Necrosis and fibrosis were reduced in the muscle fibers. These findings suggest that adipose-derived stem cells promote the re- generation and survival of muscle cells by inhibiting apoptosis and fibrosis, thereby alleviating muscle damage in muscular dystrophy.

Stem cell transplantation for treating Duchenne muscular dystrophy A Web of Science-based literature analysis

OBJECTIVE： To identify global research trends in stem cell transplantation for treating Duchenne muscular dystrophy using a bibliometric analysis of Web of Science. DATA RETRIEVAL： We performed a bibliometric analysis of studies on stem cell transplantation for treating Duchenne muscular dystrophy from 2002 to 2011 retrieved from Web of Science. SELECTION CRITERIA： Inclusion criteria： （a） peer-reviewed published articles on stem cell transplantation for treating Duchenne muscular dystrophy indexed in Web of Science; （b） original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material, and news items; and （c） publication between 2002 and 2011. Exclusion criteria： （a） articles that required manual searching or telephone access; （b） documents that were not published in the public domain; and （c） corrected papers. MAIN OUTCOME MEASURES： （1）Annual publication output; （2） distribution according to subject areas; （3） distribution according to journals; （4） distribution according to country; （5） distribution according to institution; （6） distribution according to institution in China; （7） distribution according to institution that cooperated with Chinese institutions; （8） top-cited articles from 2002 to 2006; （9） top-cited articles from 2007 to 2011. RESULTS： A total of 318 publications on stem cell transplantation for treating Duchenne muscular dystrophy were retrieved from Web of Science from 2002 to 2011, of which almost half derived from American authors and institutes. The number of publications has gradually increased over the past 10 years. Most papers appeared in journals with a focus on gene and molecular research, such as Molecular Therapy, Neuromuscular Disorders, and PLoS One. The 10 most-cited papers from 2002 to 2006 were mostly about different kinds of stem cell transplantation for muscle regeneration, while the 10 most-cited papers from 2007 to 2011 were mostly about new techniques of stem cell transplantation for treating Duchenne muscular dystrophy. CONCLUSION： The publications on stem cell transplantation for treating Duchenne muscular dystrophy were relatively few. It also needs more research to confirm that stem cell therapy is a reliable treatment for Duchenne muscular dystrophy.

Limb-girdle muscular dystrophy subtypes First-reported cohort from northeastern China

The relative frequencies of different subtypes of limb-girdle muscular dystrophies vary widely among different populations. We estimated the percentage of limb-girdle muscular dystrophy subtypes in Chinese people based on 68 patients with limb-girdle muscular dystrophy from the Myology Clinic, Neurology Department, First Hospital of Jilin University, China. A diagnosis of calpainopathy was made in 12 cases （17%）, and dysferlin deficiency in 10 cases （15%）. Two biopsies revealed α-sarcoglycan deficiency （3%）, and two others revealed a lack of caveolin-3 （3%）. A diagnosis of unclassified limb-girdle muscular dystrophy was made in the remaining patients （62%）. The ap-pearances of calpain 3- and dysferlin-deficient biopsies were similar, though rimmed vacuoles were unique to dysferlinopathy, while inflammatory infiltrates were present in both these limb-girdle muscular dystrophy type 2D biopsies. Macrophages were detected in seven dysferlinopathy biop-sies. The results of this study suggest that the distribution of limb-girdle muscular dystrophy sub-types in the Han Chinese population is similar to that reported in the West. The less necrotic, re-generating and inflammatory appearance of limb-girdle muscular dystrophy type 2A, but with more lobulated fibers, supports the idea that calpainopathy is a less active, but more chronic disease than dysferlinopathy. Unusual features indicated an extended limb-girdle muscular dystrophy disease spectrum. The use of acid phosphatase stain should be considered in suspected dysferlinopathies. To the best of our knowledge, this is the first report to define the relative proportions of the various forms of limb-girdle muscular dystrophy in China, based on protein testing.

Expression of tissue inhibitor of metalloproteinase-1 in progression muscular dystrophy

Objective Tissue inhibitor of metalloproteinase-1 （TIMP-1） is a muhifunctional protein that has thc capacity to modify cellular activities and to modulate matrix turnover. This paper revealed the contributive role of TIMP-1 in progressive muscular dystrophy （PMD）. Methods We examined the expression and cellular localization of TIMP-1 protein using biopsied frozen muscle from patients with Duchenne muscular dystrophy （DMD）, Becker muscular dystrophy （BMD） , congenital muscular dystrophy （CMD） by immunohistochemistry, double immunofluorescence and Western blot analysis. Results The results of immunohistochemistry and double immunofluorescence showed that TIMP-1 was positive only in vascular endothelial cells of normal muscles. Immunohistochemistry and Western blot analysis showed that the staining intensity was distinctly increased in some dystrophic muscles of PMD for TIMP-1. Double immunofluorescence revealed that TIMP-1 strongly expressed in the regenerating muscle fibers, macrophages and macrophage infiltrating necrotic fibers. Some activated fibroblasts in endomysium and perimysium of DMD and CMD muscles were also positive for TIMP- 1. Conclusion The functional consequence of overexpression of TIMP-1 in the dystrophic muscles is unknown, but the elevated local expression of TIMP-1 in diseased muscles of PMD and their distinct distribution pattern provide evidence that TIMP-1 may participate in the pathogenesis of PMD.

Congenital muscular dystrophy caused by beta1,3-Nacetylgalactosaminyltransferase 2 gene mutation:Two case reports

BACKGROUND Mutations in the beta1,3-N-acetylgalactosaminyltransferase 2(B3GALNT2)gene can lead to impaired glycosylation ofα-dystroglycan,which,in turn,causes congenital muscular dystrophy(CMD).The clinical phenotypes of CMD are broad,and there are only a few reports of CMD worldwide.CASE SUMMARY This report describes the cases of two children with CMD caused by B3GALNT2 gene mutation.The main manifestations of the two cases were abnormal walking posture,language development delay,and abnormal development of the white matter.Case 2 also had unreported symptoms of meningocele and giant arachnoid cyst.Both cases had compound heterozygous mutations of the B3GALNT2 gene,each containing a truncated mutation and a missense mutation,and three of the four loci had not been reported.Nineteen patients with CMD caused by B3GALNT2 gene mutation were found in the literature.Summary and analysis of the characteristics of CMD caused by B3GALNT2 gene mutation showed that 100%of the cases had nervous system involvement.Head magnetic resonance imaging often showed abnormal manifestations,and more than half of the children had eye and muscle involvement;some of the gene-related symptoms were self-healing.CONCLUSION B3GALNT2 gene can be used as one of the candidate genes for screening CMD,cognitive development retardation,epilepsy,and multiple brain developmental malformations in infants.

Anesthesia management in a pediatric patient with Becker muscular dystrophy undergoing laparoscopic surgery:A case report

BACKGROUND Patients with Becker muscular dystrophy(BMD)have a high risk of developing hyperkalemia,rhabdomyolysis,and malignant hyperthermia when exposed to volatile anesthetics and depolarizing muscle relaxants.Patients with BMD are also prone to respiratory depression after general anesthesia.Thus,it is extremely challenging for anesthesiologists to manage anesthesia in BMD patients,particularly in pediatric BMD patients.Here,we present successful anesthesia management using transversus abdominis plane block(TAPB)combined with total intravenous anesthesia(TIVA)in a pediatric BMD patient undergoing laparoscopic inguinal hernia repair.CASE SUMMARY A 2-year-old boy,weighing 15 kg,with BMD,was scheduled for laparoscopic inguinal hernia repair.TIVA was used for induction,and continuous infusions of short-acting intravenous anesthetics combined with TAPB were performed for anesthesia maintenance.Moreover,TAPB provided good postoperative analgesia.The patient underwent uneventful surgery and anesthesia,and over the 17 mo follow-up period showed no anesthesia-induced complications.CONCLUSION TAPB combined with TIVA,using short-acting intravenous anesthetic agents,can provide safe and effective anesthesia management in pediatric BMD patients undergoing short-term abdominal surgery.

Myocardial Protection with Beta Blocker Treatment in Infants with Heart Failure Due to Congenital Heart Defects and Duchenne Muscular Dystrophy

Our first intention to treat infants’ heart failure with beta blockers was to improve the clinical condition as shown in our prospective randomized trial. We only use non-selective beta blockers in these infants, carvedilol in those with left ventricular dysfunction and propranolol in those with congenital heart disease without ventricular dysfunction. Despite a significant improvement of Ross’s heart failure score, we could not convince most colleagues within the last 25 years if the concept of neurohumoral activation in heart failure is not well-established pediatric cardiology. Recently, Honghai Liu et al. published that cardiomyocyte cytokinesis failure was increased in congenital heart disease. Inactivation of the beta adreno receptors genes and administration of the beta-blocker propranolol increased cardiomyocyte division in neonatal mice, which increased the number of cardiomyocytes (endowment) and conferred benefit after myocardial infarction in adults. We currently realize that propranolol in infants with congenital heart disease not only decrease highly elevated NT-Pro-BNP values but also decrease cardiac troponin T values that may indicate myocardial injury due to neurohumoral activation. We reproduce this observation, primarily seen in infants with congenital heart disease, in an infant with Duchenne muscular dystrophy. These observations were in good accordance with current data from H. Liu et al., who showed that treatment with non-selective beta blockers early after birth might rescue cytokinesis defects and prevent heart dysfunction in adulthood in a mouse model.

Homozygous deletion, c. 1114-1116del, in exon 8 of the CRPPA gene causes congenital muscular dystrophy in Chinese family: A case report

BACKGROUND Congenital muscular dystrophy(CMD)is a clinically and genetically heterogeneous group of inherited muscle disorders.Mutations in the CRPPA gene(encoding CDPLribitol pyrophosphorylase A)are recognized as causative factors of dystroglycanopathies,a subtype of CMD with defects in glycosylation.CASE SUMMARY The present study examined a Chinese family,whose proband presented mainly with muscle weakness in both lower limbs but without brain and eye symptoms.In this family,a homozygous deletion,c.1114-1116del(p.V372del),was identified in exon 8 of CRPPA in the proband,while a heterozygous deletion was identified in the proband’s father and mother,who lacked symptoms.A mild dystroglycanopathy of CMD was diagnosed.CONCLUSION The findings of this study expanded the clinical and mutational spectrum of patients with CMD associated with CRPPA mutations.

Ventilation function changes in patients with Duchenne muscular dystrophy under and over 12 years of age Analysis of 65 cases

BACKGROUND：Previous studies indicate that vital capacity in patients with Duchenne muscular dystrophy increases with age when they are under 12 years old, and decreases from 13 or 14 years of age; however, recent studies indicate that the vital capacity in patients with Duchenne muscular dystrophy begins to decrease even before 12 years of age. OBJECTIVE： To verify if the vital capacity in patients with Duchenne muscular dystrophy decreases before the age of 12 years and to observe the effect of rehabilitation exercise on vital capacity. DESIGN, TIME AND SETTING： The case analysis was performed at the Department of Neurology, The First Affiliated Hospital of Sun Yat-Sen University （Guangzhou, Guangdong Province, China） from December 2004 to January 2006. PARTICIPANTS： Sixty-five male patients diagnosed as having Duchenne muscular dystrophy and who underwent pulmonary ventilation function examination at the Department of Neurology, The First Affiliated Hospital of Sun Yat-Sen University （Guangzhou, Guangdong Province, China） from December 2004 to January 2006; ages ranged from 6 to 22 years old. METHODS： The ventilation function of 65 patients was determined using a Sensor Medics 2100 pulmonary function test apparatus （USA）, and the data obtained were subjected to statistical analysis comparing patients under 12 years of age and those above 13 years of age, and comparing those who performed rehabilitation exercise with those who did not. MAIN OUTCOME MEASURES： Forced vital capacity （FVC）; forced expiratory volume in one second （FEV1）; maximal voluntary ventilation （MMV）; the ratio of forced expiratory volume in one second and forced vital capacity （FEV1/FVC）; each measured value as a percentage of the corresponding predicted value. RESULTS： There were no significant differences in FVC, FEV1 and MMV between patients under 12 years of age and those above 13 years of age （P 〉 0.05）. The FVC, FEV1 and MMV values, as percentages of the predicted values, were, in patients under 12 years old, significantly higher than those in patients older than 13 （P 〈 0.05）. All ventilation function parameters except FEV1/FVC in patients undergoing rehabilitation exercise were higher than those in patients without rehabilitation exercise. This difference was not significant in patients under 12 years of age, but was statistically significant in those older than 13 years （P 〈 0.05）. CONCLUSION： Although the values of ventilation function measured increase with age in Duchenne muscular dystrophy patients less than 12 years of age, real ventilation function is already damaged. Thirteen years of age is an important time point for pulmonary function change. Rehabilitation exercise can slow down the process of pulmonary function exacerbation in Duchenne muscular dystrophy patients, especially when therapy starts before 12 years of age.

Clinical manifestations and prenatal diagnosis of Ullrich congenital muscular dystrophy: A case report

BACKGROUND Ullrich congenital muscular dystrophy(UCMD)is one of the collagen-VI-related myopathies caused by mutations of COL6A1,COL6A2,and COL6A3 genes.Affected individuals are characterized by muscle weakness,proximal joint contracture,distal joint hyperlaxity,and progressive respiratory failure.There is currently no cure for UCMD.Here,we report the clinical manifestations and prenatal diagnosis of compound heterozygous mutations of the COL6A2 gene in a Chinese family with UCMD.CASE SUMMARY A 3-year-old boy,his 4-year-old brother,their parents,and a 20-wk-old fetus in the mother’s womb were included in the study.The brothers had the typical manifestations of the early-severe subtype:A delayed motor milestone(never walking independently),torticollis,scoliosis,proximal joint contracture,distal joint hyperextension,right hip joint dislocation,and calcaneal protuberance.Both brothers were found by whole-exome sequencing and Sanger sequencing to carry two mutations of the COL6A2 gene(c.1353_c.1354insC,p.Arg453Profs-Ter42/c.2105G>A,p.Trp702Ter).The absence of collagen VI staining in the younger brother’s muscle was identified accurately.Genetic counseling and prenatal diagnosis were crucial for the family,as the autosomal recessive genetic disease affected a quarter of the patient’s siblings.The fetus of the mother’s third child underwent prenatal diagnosis and carried the same two mutations of COL6A2,confirmed in the amniotic fluid by multiplex ligation-dependent probe amplification and short tandem repeats.After a painful psychological struggle,the parents finally decided to terminate the pregnancy.CONCLUSION We report a Chinese family suffering from UCMD.By clarifying the COL6A2 mutations in the probands,the parents had the opportunity to opt for voluntary interruption of the third UCMD pregnancy.

Tetramethylpyrazine Nitrone Improved Motor Deficits and Alleviated Dystrophic Muscle Pathology in the <i>mdx</i>Mouse Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a lethal X-linked recessive neuromuscular disorder caused by mutations in the dystrophin encoding gene, with the characteristics of a severe and progressive destruction of muscle structure and function. Skeletal muscle fibrosis is one of the pathological features of DMD. Tetramethylpyrazine (2,3,5,6-tetramethylpyrazine, TMP) has been demonstrated to reduce heart and liver fibrosis. Meanwhile, previous studies showed that Tetramethylpyrazine nitrone (TBN), a nitrone derivative of TMP, has promising therapeutic effects in several neurodegenerative models and is more potent than TMP. In this study, we investigated the potential effect of TBN on the mdx mouse model of DMD. Eight-week-old mdx mice were administered with TBN (30 mg/kg) intragastrically twice daily, with deflazacort (1 mg/kg) once a day as a positive control, for a total of 24 weeks. Behavioral tests including pole-climbing open-field test were monitored every 4 weeks. Histopathological assessment was conducted in the gastrocnemius and diaphragm muscles. The effects of TBN on protein levels of dysferlin were measured by immunohistochemistry. TBN significantly reduced the climbing time in pole test and increased the total distance moved in an open-field test of mdx mice. TBN attenuated fibrosis in the gastrocnemius and diaphragmatic muscles. In addition, TBN protected gastrocnemius muscle fibers via increasing expression of the dysferlin in mdx mice. In conclusion, this study demonstrated that TBN could improve the motor deficits and muscle pathology of mdx mouse, and it is worth further exploring the mechanism of action of TBN for DMD treatment.

Disease Prevention and Alleviation by Human Myoblast Transplantation

Myoblast implantation is a unique, patented technology of muscle regeneration being tested in Phase III clinical trials of muscular dystrophy, ischemic cardiomyopathy, Phase II trial of cancer, and Phase I trial of Type II diabetes. Differentiated and committed, myoblasts are not stem cells. Implanted myoblasts fuse spontaneously among themselves, replenishing genetically normal myofibers. They also fuse with genetically abnormal myofibers of muscular dystrophy, cardiomyopathy, or Type II diabetes, transferring their nuclei containing the normal human genome to provide stable, long-term expression of the missing gene products. They develop to become cardiomyocytes in the infracted myocardium. Myoblasts transduced with VEGF165 allow concomitant regeneration of blood capillaries and myofibers. They are potent biologics for treating heart failure, ischemic cardiomyopathy, diabetic ischemia, erectile dysfunction, and baldness. Myoblasts, because of their small size, spindle shape, and resilience, can grow within wrinkles and on skin surfaces, thus enhancing the color, luster and texture of the skin “plated” with them. They can be injected subcutaneously as a cellular filler to reduce wrinkles. Intramuscular injection of myoblasts can augment the size, shape, consistency, tone and strength of muscle groups, improving the lines, contours and vitality to sculpt a youthful appearance. This highly promising technology has great social economic values in treating hereditary, fatal and debilitating disease conditions.

Transgene expression and differentiation of baculovirus-transduced adipose-derived stem cells from dystrophin-utrophin double knock-out mouse

In this study, recombinant baculovirus carrying the microdystrophin and β-catenin genes was used to infect adipose-derived stem cells from a dystrophin-utrophin double knock-out mouse. Results showed that, after baculovirus transgene infection, microdystrophin and β-catenin genes were effectively expressed in adipose-derived stem cells from the dystrophin-utrophin double knock-out mouse. Furthermore, this transgenic expression promoted adipose-derived stem cell differentiation into muscle cells, but inhibited adipogenic differentiation. In addition, protein expression related to the microdystrophin and Wnt/β-catenin signaling pathway was upregulated. Our experimental findings indicate that baculovirus can successfully deliver the microdystrophin and β-catenin genes into adipose-derived stem cells, and the microdystrophin and Wnt/β-catenin signaling pathway plays an important role in myogenesis of adipose-derived stem cells in the dystrophin-utrophin double knock-out mouse.

A sandwich ELISA kit reveals marked elevation of titin N-terminal fragment levels in the urine of mdx mice

The mdx mouse is a model of Duchenne muscular dystrophy(DMD),a fatal progressive muscle wasting disease caused by dystrophin deficiency,and is used most widely in preclinical studies.Mice with dystrophin deficiency,however,show milder muscle strength phenotypes than humans.In human,the introduction of a sandwich enzyme-linked immunosorbent assay(ELISA)kit revealed a more than 700-fold increase in titin N-terminal fragment levels in the urine of pediatric patients with DMD.Notably,the urinary titin level declines with aging,reflecting progression of muscle wasting.In mouse,development of a highly sensitive ELISA kit has been awaited.Here,a sandwich ELISA kit to measure titin N-terminal fragment levels in mouse urine was developed.The developed kit showed good linearity,recovery,and repeatability in measuring recombinant or natural mouse titin N-terminal fragment levels.The titin N-terminal fragment concentration in the urine of mdx mice was more than 500-fold higher than that of normal mice.Urinary titin was further analyzed by extending the collection of urine samples to both young(3-11 weeks old)and aged(56-58 weeks old)mdx mice.The concentration in the young group was significantly higher than that in the aged group.It was concluded that muscle protein breakdown is active and persistent in mdx mice even though the muscle phenotype is mild.Our results provide an opportunity to develop DMD treatments that aim to alleviate muscle protein breakdown by monitoring urinary titin levels.

Single Cell Analysis of Dystrophin and SRY Gene by Using Whole Genome Amplification

ve To develop a reliable and sensitive method for detection of sex and multi-loci of Duchenne muscular dystrophy (DMD) gene in single cell

In vitro study of micro-dystrophin gene-modified mesenchymal stem cells

BACKGROUND： Studies have shown that the transplantation of mesenchymal stem cells （MSCs） improves dystrophin expression in muscle cell membrane of mdx mice and plays a role in ameliorating sport injuries to the myocyte. In addition, dystrophin gene plasmid injection exhibits therapeutic effect in mdx mice. However, these two methods exhibit shortcomings, such as low rate of post-transplantation expression. Therefore, the present study determined the combinatorial effects of these two methods. OBJECTIVE： To transfect and observe effects of pSL139 plasmid carrying the micro-dystrophin gene into MSCs, as well as in vitro micro-dystrophin gene expression in transfected MSCs. DESIGN, TIME AND SETTING： A comparative, molecular biology study was performed at the Laboratory of Tissue Engineering, West China Medical Center, Sichuan University from March 2007 to February 2008. MATERIALS： The pSL139 plasmid was cloned and provided by the Department of Neurology, Washington University, USA. Lipofectamine 2000 was purchased from Invitrogen, USA. Mouse anti-human dystrophin N-based terminal monoclonal antibody was purchased from Chemicon, USA. METHODS： Differential velocity adherent technique and density gradient centrifugation were combined to separate and culture MSCs from C57/BL10 mice. The cells were induced to trans-differentiate into osteoblasts. Subsequently, the Lipofectamine 2000 method was used to mediate transfection of plasmid pSL139 into third generation MSCs. MAIN OUTCOME MEASURES： Semi-quantitative reverse transcription polymerase-chain reaction and immunofluorescence were respectively employed to detect micro-dystrophin mRNA and protein expressions in MSCs. RESULTS： At 48 hours after MSC transfection with plasmid pSL139, a 379-kb target band was observed by agarose gel electrophoresis. Immunofluorescence revealed micro-dystrophin expression up to 45%-55%. CONCLUSION： Micro-dystrophin mRNA and protein were highly expressed in pSL139-transfected MSCs, which provided a method for efficient expression of dystrophin.

Using Fluorescence in situ Hybridization to Identify DMD/BMD Deletion Carriers

Objective To identify the deletions in Duchenne/Becker muscular dystrophy (DMD/ BMD) by using fluorescence in situ hybridization (FISH)Methods The exon-specific cosmid DNA probes (representing 18 exons) were used to perform one-color FISH on metaphase and interphase preparations. The peripheral blood samples from 9 normal people (4 males and 5 females) and 5 females from independent deletion DMD/BMD families, as well as 2 amniotic fluid specimens and 2 chorionic villus samples (CVS) from normal pregnant females were analyzed. Results 72%-100% of peripheral blood lymphocyte metaphases or interphases, 60% -70% of amniocyte interphases, and 95 - 99% of chorionic villus cell interphases showed expected signals. One suspected female was identified as deletion carriers and two were excluded.Conclusion FISH in combination with other available techniques allows efficient screening of DMD/BMD deletion carriers, which also lay the ground work for prenatal diagnosis for potential fetal carriers.