Evaluation of effects of continued corticosteroid treatment on cardiac and pulmonary function in non-ambulatory males with Duchenne muscular dystrophy from MD STARnet.

INTRODUCTION/AIMS: Corticosteroids have been shown to improve muscle strength and delay loss of ambulation (LOA) in Duchenne muscular dystrophy (DMD) and are considered standard of care despite significant side-effects. The objective of this study is to evaluate whether corticosteroid treatment after LOA is beneficial for cardiac or pulmonary functions among boys with DMD. METHODS: We used the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) to characterize associations between corticosteroid use and onset of abnormal left ventricular (LV) function or abnormal percent predicted forced vital capacity (ppFVC) among 398 non-ambulatory boys with DMD. Kaplan-Meier curve estimation was used to compare time to onset by corticosteroid use groups; Cox proportional hazards modeling was used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals. RESULTS: We found no differences in time to onset of abnormal LV function by corticosteroid use groups. We observed a longer time from LOA to first abnormal ppFVC in boys that were treated with corticosteroid ≥1 y beyond LOA compared with those with no corticosteroid use or those who stopped corticosteroid use within 1 y of LOA. DISCUSSION: Our findings show no association of corticosteroid use beyond LOA with the onset of abnormal LV function, but a significant association with a delay in onset of abnormal ppFVC. Prospective studies of corticosteroid use in boys with DMD who have lost ambulation may identify benefits and can better elucidate risks, allowing for more effective counseling of patients on continuing treatment after LOA.

A population-based study of scoliosis among males diagnosed with a dystrophinopathy identified by the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet).

INTRODUCTION/AIMS: Scoliosis is a common comorbidity among individuals diagnosed with a dystrophinopathy. We examined associations between clinical predictors and scoliosis in childhood-onset dystrophinopathy. METHODS: The progression and treatment of scoliosis were obtained from data collected by the US population-based Muscular Dystrophy Surveillance, Tracking, and Research Network. Associations between loss of independent ambulation (LoA) and corticosteroid use and scoliosis outcomes (ages at or exceeding Cobb angle thresholds [10°, 20°, 30°]; surgery) were estimated using Kaplan-Meier curve estimation and extended Cox regression modeling. RESULTS: We analyzed curvature data for 513 of 1054 individuals ascertained. Overall, approximately one-half had at least one radiograph and one-quarter had a curvature of at least 20°. The average maximum curvature was 25.0° (SD = 21.5°) among all individuals and 42.8° (SD = 18.8°) among those recommended for surgery. Higher adjusted hazards ratio of curvature (aHR(curvature) [95% confidence interval]) were found among individuals with LoA compared to those without LoA (aHR(10)  = 6.2 [4.4, 8.7], aHR(20)  = 15.3 [7.4, 31.7], aHR(30)  = 31.6 [7.7, 128.9]), among individuals who did not use corticosteroids compared to those who did (aHR(10)  = 1.2 [0.9, 1.7], aHR(20)  = 1.8 [1.1, 2.7], aHR(30)  = 2.3 [1.3, 4.0]), and among non-ambulatory individuals who used corticosteroids after LoA compared to those who did not (aHR(10)  = 1.8 [1.2, 2.8], aHR(20)  = 1.6 [1.0, 2.6], aHR(30)  = 3.6 [1.6, 7.9]). Scoliosis surgery among individuals with LoA who did not use corticosteroids was more than double compared to those who used (aHR = 2.3 [1.3, 4.2]). DISCUSSION: Our retrospective observational study suggests corticosteroids may delay spinal curvature progression and need for scoliosis surgery. Continuing corticosteroids after LoA also showed potential benefits of delaying curvature progression, additional studies are needed to confirm this finding or address the magnitude of benefit.

Association of genetic mutations and loss of ambulation in childhood-onset dystrophinopathy.

BACKGROUND: Quantifying associations between genetic mutations and loss of ambulation (LoA) among males diagnosed with childhood-onset dystrophinopathy is important for understanding variation in disease progression and may be useful in clinical trial design. METHODS: Genetic and clinical data from the Muscular Dystrophy Surveillance, Tracking, and Research Network for 358 males born and diagnosed from 1982 to 2011 were analyzed. LoA was defined as the age at which independent ambulation ceased. Genetic mutations were defined by overall type (deletion/duplication/point mutation) and among deletions, those amenable to exon-skipping therapy (exons 8, 20, 44-46, 51-53) and another group. Cox proportional hazards regression modeling was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: Mutation type did not predict time to LoA. Controlling for corticosteroids, Exons 8 (HR = 0.22; 95% CI = 0.08, 0.63) and 44 (HR = 0.30; 95% CI = 0.12, 0.78) were associated with delayed LoA compared to other exon deletions. CONCLUSIONS: Delayed LoA in males with mutations amenable to exon-skipping therapy is consistent with previous studies. These findings suggest that clinical trials including exon 8 and 44 skippable males should consider mutation information prior to randomization.

The effect of steroid treatment on weight in nonambulatory males with Duchenne muscular dystrophy.

To describe the long-term effect of steroid treatment on weight in nonambulatory males with Duchenne Muscular Dystrophy (DMD), we identified 392 males age 7-29 years with 4,512 weights collected after ambulation loss (176 steroid-naïve and 216 treated with steroids ≥6 months) from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet). Comparisons were made between the weight growth curves for steroid-naïve males with DMD, steroid-treated males with DMD, and the US pediatric male population. Using linear mixed-effects models adjusted for race/ethnicity and birth year, we evaluated the association between weight-for-age and steroid treatment characteristics (age at initiation, dosing interval, cumulative duration, cumulative dose, type). The weight growth curves for steroid-naïve and steroid-treated nonambulatory males with DMD were wider than the US pediatric male growth curves. Mean weight-for-age z scores were lower in both steroid-naïve (mean = -1.3) and steroid-treated (mean = -0.02) nonambulatory males with DMD, compared to the US pediatric male population. Longer treatment duration and greater cumulative dose were significantly associated with lower mean weight-for-age z scores. Providers should consider the effect of steroid treatment on weight when making postambulation treatment decisions for males with DMD.

Multimodal SHG-2PF Imaging of Microdomain Ca2+-Contraction Coupling in Live Cardiac Myocytes.

RATIONALE: Cardiac myocyte contraction is caused by Ca(2+) binding to troponin C, which triggers the cross-bridge power stroke and myofilament sliding in sarcomeres. Synchronized Ca(2+) release causes whole cell contraction and is readily observable with current microscopy techniques. However, it is unknown whether localized Ca(2+) release, such as Ca(2+) sparks and waves, can cause local sarcomere contraction. Contemporary imaging methods fall short of measuring microdomain Ca(2+)-contraction coupling in live cardiac myocytes. OBJECTIVE: To develop a method for imaging sarcomere level Ca(2+)-contraction coupling in healthy and disease model cardiac myocytes. METHODS AND RESULTS: Freshly isolated cardiac myocytes were loaded with the Ca(2+)-indicator fluo-4. A confocal microscope equipped with a femtosecond-pulsed near-infrared laser was used to simultaneously excite second harmonic generation from A-bands of myofibrils and 2-photon fluorescence from fluo-4. Ca(2+) signals and sarcomere strain correlated in space and time with short delays. Furthermore, Ca(2+) sparks and waves caused contractions in subcellular microdomains, revealing a previously underappreciated role for these events in generating subcellular strain during diastole. Ca(2+) activity and sarcomere strain were also imaged in paced cardiac myocytes under mechanical load, revealing spontaneous Ca(2+) waves and correlated local contraction in pressure-overload-induced cardiomyopathy. CONCLUSIONS: Multimodal second harmonic generation 2-photon fluorescence microscopy enables the simultaneous observation of Ca(2+) release and mechanical strain at the subsarcomere level in living cardiac myocytes. The method benefits from the label-free nature of second harmonic generation, which allows A-bands to be imaged independently of T-tubule morphology and simultaneously with Ca(2+) indicators. Second harmonic generation 2-photon fluorescence imaging is widely applicable to the study of Ca(2+)-contraction coupling and mechanochemotransduction in both health and disease.

Perceived quality of life among caregivers of children with a childhood-onset dystrophinopathy: a double ABCX model of caregiver stressors and perceived resources.

BACKGROUND: Duchenne and Becker muscular dystrophies, collectively referred to as dystrophinopathies, are recessive X-linked disorders characterized by progressive muscle weakness and ultimately cardiac and respiratory failure. Immediate family members are often primary caregivers of individuals with a dystrophinopathy. METHODS: We explored the impact of this role by inviting primary caregivers (n = 209) of males diagnosed with childhood-onset dystrophinopathy who were identified by the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet) to complete a mailed questionnaire measuring perceived social support and stress, spirituality, and family quality of life (FQoL). Bivariate and multivariate analyses examined associations between study variables using the Double ABCX model as an analytic framework. RESULTS: Higher stressor pile-up was associated with lower perceived social support (r = -0.29, p < .001), availability of supportive family (r = -0.30, p < .001) or non-family (r = -0.19, p < .01) relationships, and higher perceived stress (r = 0.33, p < .001); but not with spirituality (r = -0.14, p > 0.05). FQoL was positively associated with all support measures (correlations ranged from: 0.25 to 0.58, p-values 0.01-0.001) and negatively associated with perceived stress and control (r = -0.49, p < .001). The association between stressor pile-up and FQoL was completely mediated through global perceived social support, supportive family relationships, and perceived stress and control; supportive non-family relationships did not remain statistically significant after controlling for other mediators. CONCLUSIONS: Findings suggest caregiver adaptation to a dystrophinopathy diagnosis can be optimized by increased perceived control, supporting family resources, and creation of a healthy family identity. Our findings will help identify areas for family intervention and guide clinicians in identifying resources that minimize stress and maximize family adaptation.

Smart and Fast Blood Counting of Trace Volumes of Body Fluids from Various Mammalian Species Using a Compact, Custom-Built Microscope Cytometer.

We report an accurate method to count red blood cells, platelets, and white blood cells, as well as to determine hemoglobin in the blood of humans, horses, dogs, cats, and cows. Red and white blood cell counts can also be performed on human body fluids such as cerebrospinal fluid, synovial fluid, and peritoneal fluid. The approach consists of using a compact, custom-built microscope to record large field-of-view, bright-field, and fluorescence images of samples that are stained with a single dye and using automatic algorithms to count blood cells and detect hemoglobin. The total process takes about 15 min, including 5 min for sample preparation, and 10 min for data collection and analysis. The minimum volume of blood needed for the test is 0.5 µL, which allows for minimally invasive sample collection such as using a finger prick rather than a venous draw. Blood counts were compared to gold-standard automated clinical instruments, with excellent agreement between the two methods as determined by a Bland-Altman analysis. Accuracy of counts on body fluids was consistent with hand counting by a trained clinical lab scientist, where our instrument demonstrated an approximately 100-fold lower limit of detection compared to current automated methods. The combination of a compact, custom-built instrument, simple sample collection and preparation, and automated analysis demonstrates that this approach could benefit global health through use in low-resource settings where central hematology laboratories are not accessible.

Patterns of growth in ambulatory males with Duchenne muscular dystrophy.

OBJECTIVE: To provide weight-for-age, height-for-age, and body mass index-for-age growth reference standards for ambulatory, steroid-naïve males, ages 2-12 years, with Duchenne muscular dystrophy (DMD) and to compare these growth curves to the 2000 Centers for Disease Control and Prevention growth charts for boys, which serve as references of physical size and growth for the general male pediatric population in the US. STUDY DESIGN: Through a multi-state population-based surveillance of individuals with muscular dystrophy, a total of 1877 weight and 1544 height measurements ascertained during 1985-2010 from 513 males with DMD were obtained retrospectively from medical record review. Cases were classified as DMD if loss of ambulation occurred before the 12th birthday or, if younger than 12 years and still ambulating, the earliest symptoms of dystrophinopathy occurred before the 6th birthday. Each growth chart was constructed using 5 percentiles: 10th, 25th, 50th, 75th, and 90th. Smoothing procedures were applied in 2 stages to the irregular plots of the empirical percentile values. RESULTS: A set of growth curves, derived from a large cohort of male youth with DMD, are presented. These curves demonstrate that DMD males are shorter and tend to the extremes of weight and body mass index compared with the general male pediatric population in the US. CONCLUSION: Charts representing the pattern of growth in ambulatory, steroid-naïve males with DMD can facilitate monitoring of growth and early detection of unusual growth patterns. Use of these growth standards also will assist in monitoring responses to corticosteroid treatment.

Differentiation of Pediatric-Onset Duchenne and Becker Muscular Dystrophy Subphenotypes Using Data from the Muscular Dystrophy Surveillance Tracking and Research Network (MD STARnet).

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) phenotypes are used to describe disease progression in affected individuals. However, considerable heterogeneity has been observed across and within these two phenotypes, suggesting a spectrum of severity rather than distinct conditions. Characterizing the phenotypes and subphenotypes aids researchers in the design of clinical studies and clinicians in providing anticipatory guidance to affected individuals and their families. Using data from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet), we used K-means cluster analysis to group phenotypically similar males with pediatric-onset dystrophinopathy. We identified four dystrophinopathy clusters: Classical BMD, Classical DMD, late ambulatory DMD, and severe DMD. The clusters that we identified align with both 'classical' and 'non-classical' dystrophinopathy described in the literature. Individuals with dystrophinopathies have heterogenous clinical presentations that cluster into phenotypically similar groups. Use of clinically-derived phenotyping may provide a clearer understanding of disease trajectories, reduce variability in study results, and prevent exclusion of certain cohorts from analysis. Findings from studying subphenotypes may ultimately improve our ability to predict disease progression.

A Conversation Between Past and Present Chairs of the American Board of Physical Medicine and Rehabilitation: Four Decades of History and the Future of Board Certification.

ABSTRACT: On the 75th anniversary of the founding of the American Board of Physical Medicine and Rehabilitation, 11 of the surviving chairs of the board convened virtually to reflect on the past 40 years of major trends for the accrediting body of physiatrists. The field rapidly expanded in the 1980s, driven by changes in the reimbursement environment. This rapid expansion drove an improvement in the caliber of residents choosing the field and in the quality of training programs. As physical medicine and rehabilitation evolved from a small- to medium-sized specialty, the board addressed many challenges: securing a credible position within the American Board of Medical Specialties; addressing a rising demand for subspecialty certification; improving training and exposure to physiatry; enhancing the quality of the accreditation process; and reducing the burden of accreditation on diplomates. The future development of physiatry includes improving diversity, equity, and inclusion, while restoring provider morale, well-being, and meaningfulness in work. Although challenges remain, physiatry as a field has grown to be well established through the board's efforts and respected within the larger medical community.

Palliative care services in families of males with Duchenne muscular dystrophy.

INTRODUCTION: Palliative care services that address physical pain and emotional, psychosocial, and spiritual needs may benefit individuals with Duchenne muscular dystrophy (DMD). METHODS: The objective of this study was to describe the palliative care services that families of males with DMD report they receive. A questionnaire was administered to families of males with DMD born prior to January 1, 1982. Thirty-four families responded. RESULTS: Most families (85%) had never heard the term palliative care. Only attendant care and skilled nursing services showed much usage, with 44% and 50% indicating receipt of these services, respectively. Receipt of other services was reported less frequently: pastoral care (27%); respite care (18%); pain management (12%); and hospice care (6%). Only 8 respondents (25%) reported having any type of directive document in place. CONCLUSION: The data suggest a need for improved awareness of palliative care and related services among families of young men with DMD.

Long-term effect of botulinum toxin A on the hip and spine in cerebral palsy: A national retrospective cohort study in Taiwan.

OBJECTIVES: To investigate the effect of botulinum toxin A (BTA) on the development of hip dislocation and scoliosis, surgical rates for hip and spine, and mortality in cerebral palsy (CP). STUDY DESIGN: A cohort study was conducted using CP data from a Taiwan National Insurance Health Research Database. Diagnoses were defined using the International Classification of Diseases codes, 9th revision. Adjusted hazard ratios for outcomes were calculated using Cox regression analysis and adjusted for the following variables: BTA injection, sex, age, severities of CP, comorbidities, location, urbanization level, and level of care. RESULTS: A total of 1,405 CP children (670 female vs. 735 male), 281 in the BTA group and 1,124 in the controls, were followed-up for a mean of 5 years 4 months. There were no significant differences in the outcomes in both groups, in the incidence rates of hip dislocation and scoliosis, nor in the surgical rates for hip and spine surgery. Mortality rate in the BTA group was 0.49 times lower than that in the controls (p = 0.001). Moderate to severe types of CP had higher incidence rates of hip dislocation, scoliosis, hip surgery, spine surgery, and mortality. CONCLUSION: Moderate to severe types of CP had poorer outcomes in all aspects, including a higher risk of hip dislocation, scoliosis, surgical rate for hip and spine, and mortality. Although BTA injection in children with CP proved to not significantly reduce hip dislocation and scoliosis, it is considered safe as an anti-spasticity treatment and may be beneficial for survival.

Characterizing the origin of autofluorescence in human esophageal epithelium under ultraviolet excitation.

The autofluorescence under ultraviolet excitation arising from normal squamous and columnar esophageal mucosa is investigated using multispectral microscopy. The results suggest that the autofluorescence signal arises from the superficial tissue layer due to the short penetration depth of the ultraviolet excitation. As a result, visualization of esophageal epithelial cells and their organization can be attained using wide-field autofluorescence microscopy. Our results show tryptophan to be the dominant source of emission under 266 nm excitation, while emission from NADH and collagen are dominant under 355 nm excitation. The analysis of multispectral microscopy images reveals that tryptophan offers the highest image contrast due to its non-uniform distribution in the sub-cellular matrix. This technique can simultaneously provide functional and structural imaging of the microstructure using only the intrinsic tissue fluorophores.

Reliability of the Tardieu Scale for assessing spasticity in children with cerebral palsy.

OBJECTIVE: To measure the Tardieu Scale's reliability in children with cerebral palsy (CP) when used by raters with and without experience in using the scale, before and after training. DESIGN: Single-center, intrarater and interrater reliability study. SETTING: Institutional ambulatory care. PARTICIPANTS: Referred children with CP in the pretraining phase (n=5), during training (n=3), and in the posttraining phase (n=15). INTERVENTIONS: The Tardieu Scale involves performing passive muscle stretch at 2 velocities, slow and fast. The rater derives 2 parameters; the Spasticity Angle X is the difference between the angles of arrest at slow speed and of catch-and-release or clonus at fast speed; the Spasticity Grade Y is an ordinal variable that grades the intensity (gain) of the muscle reaction to fast stretch. In phase 1, experienced raters without formalized training in the scale graded elbow, knee, and ankle plantar flexors bilaterally, without and with a goniometer. In phase 2, after training, the experienced and nonexperienced raters graded the same muscles unilaterally. MAIN OUTCOME MEASURES: Intrarater and interrater reliability of the Tardieu Scale. RESULTS: After training, nonexperienced raters had mean +/- SD intrarater and interrater agreement rates across all joints and parameters of 80%+/-14% and 74%+/-16%, respectively. For experienced raters, intrarater and interrater agreement rates before training were 77%+/-13% and 66%+/-15%, respectively, versus 90%+/-8% and 81%+/-13%, respectively, after training (P<.001 for both). Specific angle measurements at the knee were less reliable for the angles of catch measured at fast speed. Across all joints, agreement rates were similar using visual or goniometric measurements. CONCLUSIONS: Both parameters of the Tardieu Scale have excellent intrarater and interrater reliability when assessed at the elbow and ankle joints of children with CP, with no difference noted between visual and goniometric measurements. Angle measurements were less reliable at the knee joints. Training was associated with a highly significant improvement in reliability.

Efficacy of Repeat AbobotulinumtoxinA (Dysport®) Injections in Improving Gait in Children with Spastic Cerebral Palsy.

Purpose: This secondary analysis of a randomized, double-blind study plus open-label extension (NCT01249417/NCT01251380) evaluated the efficacy of abobotulinumtoxinA versus placebo in improving gait pattern in children with dynamic equinus due to cerebral palsy (CP) as assessed by the observational gait scale (OGS). Methods: Ambulatory children with CP (N = 241, aged 2-17) and dynamic equinus were randomized to treatment with abobotulinumtoxinA (10 or 15U/kg/leg) or placebo injected into the gastrocsoleus. All children received abobotulinumtoxinA in the open-label phase. Results: In the double-blind phase, abobotulinumtoxinA significantly improved OGS total scores versus placebo at Week 4 (treatment effect vs. placebo: 10U/kg/leg: 1.5 [0.7, 2.3], p = .0003; 15U/kg/leg: 1.1 [0.3, 1.9], p = .01). In the open-label phase, treatment with abobotulinumtoxinA continued to improve the OGS score at the same magnitude as seen in the double-blind study. Conclusion: Repeat treatment with abobotulinumtoxinA improved gait in children with dynamic equinus.

Delayed diagnosis in duchenne muscular dystrophy: data from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet).

OBJECTIVE: To identify key factors for the delay in diagnosis of Duchenne muscular dystrophy (DMD) without known family history. STUDY DESIGN: The cohort comes from the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STARnet), a multistate, multiple-source, population-based surveillance system that identifies and gathers information on all cases of Duchenne and Becker muscular dystrophy born since 1982. We analyzed medical records of 453 Duchenne and Becker muscular dystrophy boys to document the time course and steps taken to reach a definitive diagnosis. RESULTS: Among 156 boys without known family history of DMD prior to birth, first signs or symptoms were noted at a mean age of 2.5 years. Concerns resulted in primary care provider evaluation of the child at a mean age of 3.6 years. Mean age at time of initial creatine kinase was 4.7 years. Mean age at definitive diagnosis of DMD was 4.9 years. CONCLUSIONS: There is a delay of about 2.5 years between onset of DMD symptoms and the time of definitive diagnosis, unchanged over the previous 2 decades. This delay results in lost opportunities for timely genetic counseling and initiation of corticosteroid treatment. We recommend checking creatine kinase early in the evaluation of boys with unexplained developmental delay.

A non-contact method and instrumentation to monitor renal ischemia and reperfusion with optical spectroscopy.

The potential of NADH autofluorescence as an in vivo intrinsic optical signature to monitor tissue metabolism is well recognized and supported by experimental results mainly in animal models. In this work, we propose a non-contact implementation of this method using large area excitation and employing a normalization method to account for non-metabolic signal changes. Proof of principle in vivo experiments were carried out using an autofluorescence imaging experimental system and a rat renal ischemia model. A hand-held fiber-optic probe was utilized to test the ability of the signal normalization method to address operational conditions associated with the translation of this method to a clinical setting. Preliminary pre-clinical in vivo test of the probe system was carried out using the same rat model.

Real-time microscopic imaging of esophageal epithelial disease with autofluorescence under ultraviolet excitation.

Detection of esophageal disease in current clinical practice is limited to visualization of macroscopic epithelial morphology. In this work, we investigate high resolution autofluorescence imaging under ultra violet excitation to visualize microscopic epithelial changes related to disease progression using a bench top prototype microscope. The approach is based on the hypothesis that UV excitation light can only penetrate the superficial layer of cells resulting in autofluorescence images of the epithelial layer without using an additional image sectioning approach. The experiments were performed using ex vivo human esophagus biopsy specimens. The results indicate that cellular morphology information related to disease progression is attainable without tissue preparation.

Evaluation of the contribution of the renal capsule and cortex to kidney autofluorescence intensity under ultraviolet excitation.

The use of reduced nicotinamide adenine dinucleotide (NADH) fluorescence to gain metabolic information on kidneys in response to an alteration in oxygen availability has previously been experimentally demonstrated, but signal quantification has not, to date, been addressed. In this work the relative contribution to rat kidney autofluorescence of the capsule versus cortex under ultraviolet excitation is determined from experimental results obtained using autofluorescence microscopy and a suitable mathematical model. The results allow for a quantitative assessment of the relative contribution of the signal originating in the metabolically active cortex as a function of capsule thickness for different wavelengths.