Renal dysfunction can occur in advanced-stage Duchenne muscular dystrophy

A case of Duchenne muscular dystrophy recovered from prolonged ischemic kidney injury which emerged with a normal creatinine level

Duchenne muscular dystrophy (DMD) is an inherited disease characterized by progressive degeneration of the skeletal muscles. Renal dysfunction in patients with DMD has recently become more apparent as life expectancy has increased owing to advances in respiratory devices and heart failure therapies. A 23-year-old man with DMD who required nasal tube feeding was referred to our hospital with a 4-month history of renal dysfunction and anemia. The patient's serum creatinine (sCr) level was within the normal range (0.84 mg/dL), but his serum cystatin C level and estimated glomerular filtration rate calculated by cystatin C (5.90 mg/L and 7.5 mL/min/1.73 m2, respectively) indicated severe renal impairment. A urinalysis revealed elevated levels of protein and tubular markers. The patient's hemoglobin and erythropoietin levels indicated renal anemia. Hypotension, a collapsed inferior vena cava, and a poor tube feeding episode suggested that the kidney injury was due to renal ischemia, which progressed to tubulointerstitial kidney injury, an intrinsic kidney injury. The angiotensin-converting enzyme inhibitors and beta-blockers were discontinued, and extracellular fluid was infused. Thereafter, the patient's renal function recovered. Subsequently, the patient's urinary findings and anemia improved. Although advances in cardioprotective agents are expected to improve the prognosis of patients with DMD, it is important to consider that the number of patients with kidney injury due to renal ischemia may increase and that it is difficult to evaluate renal function using sCr level in patients with DMD because of decreased skeletal muscle mass.

Impairments and comorbidities in adults with cerebral palsy and spina bifida: a meta-analysis

Introduction

Aging with a childhood-onset disability, such as cerebral palsy (CP), spina bifida (SB), and muscular diseases (MD), comes along with significant impairments and comorbidities. Despite the increasing evidence an overall picture is lacking. This study aimed to review the literature about adults with CP/SB/MD and impairments and comorbidities to perform a meta-analysis.

Materials and methods

Embase, PubMed, Cinahl, and Google Scholar were searched (2000-2020). Search terms included adults with one of the aforementioned disabilities combined with impairments and comorbidities. If specific impairments or comorbidities were reported by at least four studies, these were included in the study. Pooled prevalence (95% Confidence Interval) of impairments/comorbidities were calculated.

Results

The search yielded 7,054 studies of which 95 were included in the meta-analysis (64 CP, 31 SB, 0 MD). In total estimates were calculated for 26 (CP) and 11 (SB) outcomes. In adults with CP, pain [56.4% (95%CI 48.8-63.8)], deformities [44.2% (95%CI 12.9-78.4)], intellectual disability [37.2% (95%CI 26.7-48.3)], and fatigue [36.9% (95%CI 24.6-50.1)] were most prevalent; renal disease [3.0% (95%CI 2.1-4.2)] and stroke/rheumatic diseases {4.8% (95%CI 3.4-6.5; 4.8% (95%CI 1.5-9.9)] respectively} were least prevalent. For adults with SB, bladder incontinence [60.0% (95%CI 50.5-69.2)], bowel incontinence [49.2% (95%CI 34.5-64.0)], pain [44.1% (95%CI 27.4-61.5)], and sleeping problems [30.3% (95%CI 4.7-65.8)] were most prevalent; diabetes [4.8% (95%CI 2.8-7.3)] and renal disease [8.7% (95%CI 2.0-19.9)] were least prevalent. The included studies showed large heterogeneity.

Conclusions

More research is needed to study health issues in adults with MD. Adults with CP or SB deal with a variety of health issues. More attention for the mental health of these adults is needed. There also is a need for accessible and adequate screening, preventive measures and clinical follow-up.

miR-378 affects metabolic disturbances in the mdx model of Duchenne muscular dystrophy

Although Duchenne muscular dystrophy (DMD) primarily affects muscle tissues, the alterations to systemic metabolism manifested in DMD patients contribute to the severe phenotype of this fatal disorder. We propose that microRNA-378a (miR-378) alters carbohydrate and lipid metabolism in dystrophic mdx mice. In our study, we utilized double knockout animals which lacked both dystrophin and miR-378 (mdx/miR-378^-/-). RNA sequencing of the liver identified 561 and 194 differentially expressed genes that distinguished mdx versus wild-type (WT) and mdx/miR-378^-/- versus mdx counterparts, respectively. Bioinformatics analysis predicted, among others, carbohydrate metabolism disorder in dystrophic mice, as functionally proven by impaired glucose tolerance and insulin sensitivity. The lack of miR-378 in mdx animals mitigated those effects with a faster glucose clearance in a glucose tolerance test (GTT) and normalization of liver glycogen levels. The absence of miR-378 also restored the expression of genes regulating lipid homeostasis, such as Acly, Fasn, Gpam, Pnpla3, and Scd1. In conclusion, we report for the first time that miR-378 loss results in increased systemic metabolism of mdx mice. Together with our previous finding, demonstrating alleviation of the muscle-related symptoms of DMD, we propose that the inhibition of miR-378 may represent a new strategy to attenuate the multifaceted symptoms of DMD.

Global, segmental and layer specific analysis of myocardial involvement in Duchenne muscular dystrophy by cardiovascular magnetic resonance native T1 mapping

BACKGROUND

Progressive cardiomyopathy accounts for almost all mortality among Duchenne muscular dystrophy (DMD) patients.‍ Thus, our aim was to comprehensively characterize myocardial involvement by investigating the heterogeneity of native T1 mapping in DMD patients using global and regional (including segmental and layer-specific) analysis across a large cohort.

METHODS

We prospectively enrolled 99 DMD patients (8.8 ± 2.5 years) and 25 matched male healthy controls (9.5 ± 2.5 years). All subjects underwent cardiovascular magnetic resonance (CMR) with cine, T1 mapping and late gadolinium enhancement (LGE) sequences. Native T1 values based on the global and regional myocardium were measured, and LGE was defined.

RESULTS

LGE was present in 49 (49%) DMD patients. Global native T1 values were significantly longer in LGE-positive (LGE +) patients than in healthy controls, both in basal slices (1304 ± 55 vs. 1246 ± 27 ms, p < 0.001) and in mid-level slices (1305 ± 57 vs. 1245 ± 37 ms, p < 0.001). No significant difference in global native T1 was found between healthy controls and LGE-negative (LGE-) patients. In segmental analysis, LGE + patients had significantly increased native T1 in all analyzed segments compared to the healthy control group. Meanwhile, the comparison between LGE- patients and healthy controls showed significantly elevated values only in the basal anterolateral segment (1273 ± 62 vs. 1234 ± 40 ms, p = 0.034). Interestingly, the epicardial layer had a significantly higher native T1 in LGE- patients than in healthy controls (p < 0.05), whereas no such pattern was noticed in the global myocardium. Epicardial layer native T1 resulted in the highest diagnostic performance for distinguishing between healthy controls and DMD patients in receiver operating curve analyses (area under the curve [AUC] 0.84 for basal level and 0.85 for middle level) when compared to global native T1 and endocardial layer native T1.

CONCLUSIONS

Myocardial regional native T1, particularly epicardial native T1, seems to have potential as a novel robust marker of very early cardiac involvement in DMD patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ( http://www.chictr.org.cn/index.aspx ) ChiCTR1800018340, 09/12/2018, Retrospectively registered.

Complexity of skeletal muscle degeneration: multi-systems pathophysiology and organ crosstalk in dystrophinopathy

Duchenne muscular dystrophy is a highly progressive muscle wasting disorder due to primary abnormalities in one of the largest genes in the human genome, the DMD gene, which encodes various tissue-specific isoforms of the protein dystrophin. Although dystrophinopathies are classified as primary neuromuscular disorders, the body-wide abnormalities that are associated with this disorder and the occurrence of organ crosstalk suggest that a multi-systems pathophysiological view should be taken for a better overall understanding of the complex aetiology of X-linked muscular dystrophy. This article reviews the molecular and cellular effects of deficiency in dystrophin isoforms in relation to voluntary striated muscles, the cardio-respiratory system, the kidney, the liver, the gastrointestinal tract, the nervous system and the immune system. Based on the establishment of comprehensive biomarker signatures of X-linked muscular dystrophy using large-scale screening of both patient specimens and genetic animal models, this article also discusses the potential usefulness of novel disease markers for more inclusive approaches to differential diagnosis, prognosis and therapy monitoring that also take into account multi-systems aspects of dystrophinopathy. Current therapeutic approaches to combat muscular dystrophy are summarised.

Non-contrast cardiovascular magnetic resonance detection of myocardial fibrosis in Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) leads to progressive cardiomyopathy. Detection of myocardial fibrosis with late gadolinium enhancement (LGE) by cardiovascular magnetic resonance (CMR) is critical for clinical management. Due to concerns of brain deposition of gadolinium, non-contrast methods for detecting and monitoring myocardial fibrosis would be beneficial.

OBJECTIVES

We hypothesized that native T1 mapping and/or circumferential (εcc) and longitudinal (εls) strain can detect myocardial fibrosis.

METHODS

156 CMRs with gadolinium were performed in 66 DMD boys and included: (1) left ventricular ejection fraction (LVEF), (2) LGE, (3) native T1 mapping and myocardial tagging (εcc-tag measured using harmonic phase analysis). LGE was graded as: (1) presence/absence by segment, slice, and globally; (2) global severity from 0 (no LGE) to 4 (severe); (3) percent LGE using full width half maximum (FWHM). εls and εcc measured using feature tracking. Regression models to predict LGE included native T1 and either εcc-tag or εls and εcc measured at each segment, slice, and globally.

RESULTS

Mean age and LVEF at first CMR were 14 years and 54%, respectively. Global εls and εcc strongly predicted presence or absence of LGE (OR 2.6 [1.1, 6.0], p = 0.029, and OR 2.3 [1.0, 5.1], p = 0.049, respectively) while global native T1 did not. Global εcc, εls, and native T1 predicted global severity score (OR 2.6 [1.4, 4.8], p = 0.002, OR 2.6 [1.4, 6.0], p = 0.002, and OR 1.8 [1.1, 3.1], p = 0.025, respectively). εls correlated with change in LGE by severity score (n = 33, 3.8 [1.0, 14.2], p = 0.048) and εcc-tag correlated with change in percent LGE by FWHM (n = 34, OR 0.2 [0.1, 0.9], p = 0.01).

CONCLUSIONS

Pre-contrast sequences predict presence and severity of LGE, with εls and εcc being more predictive in most models, but there was not an observable advantage over using LVEF as a predictor. Change in LGE was predicted by εls (global severity score) and εcc-tag (FWHM). While statistically significant, our results suggest these sequences are currently not a replacement for LGE and may only have utility in a very limited subset of DMD patients.

Kidney involvement and associated risk factors in children with Duchenne muscular dystrophy

BACKGROUND

Kidney dysfunction is a common complication in adults with Duchenne muscular dystrophy (DMD); however, little attention has been paid to kidney function in pediatric patients.

METHODS

Medical records of patients with DMD who were followed up for ≥ 12 months were retrospectively reviewed. Inclusion criteria were (i) aged 5-18 years, (ii) proven mutations in the dystrophin gene, and (iii) absence of structural anomalies of the kidney and urinary tract. Serum creatine kinase (CK) was used as an indirect marker of muscle destruction.

RESULTS

Forty-four patients (mean age, 10.9 ± 3.3 years) were included. Blood pressure was evaluated by 24-h ambulatory blood pressure monitoring in 28 patients. Hypertension was found in 9 (32.1%), eight of whom were using steroids. Mild proteinuria, hypercalciuria, hypocalciuria, and hyperphosphaturia in 24-h urine collection (n = 36) were detected in 3 (8.3%), 5 (13.9%), 7 (19.7%), and 6 (16.7%) patients, respectively. Twenty-one (58.3%) demonstrated hyperuricosuria, associated with hyperuricemia in 4. Logarithmic cystatin C (CysC) had a positive correlation to creatinine (Cr) (p = 0.001, r = 0.54), CK (p = 0.048, r = 0.30), and parathormone (PTH) (p = 0.001, r = 0.49). Moreover, the patients were divided into two groups according to median CysC value: group 1 (n = 20, CysC ≤ 0.76 mg/l) and group 2 (n = 24, CysC > 0.76 mg/l). Mean CK, PTH, and Cr levels were significantly elevated in group 2 compared with group 1 (p = 0.010, 0.033, and 0.023, respectively).

CONCLUSIONS

Long-term exposure to the excessive burden of intracellular components released from damaged muscles may be associated with an increased risk over time of chronic kidney impairment in pediatric DMD patients. Graphical abstract.

Proteomic profiling of fatty acid binding proteins in muscular dystrophy

Introduction: Duchenne muscular dystrophy is a neuromuscular disorder, which is caused by abnormalities in the DMD gene that encodes the membrane cytoskeletal protein dystrophin. Besides progressive skeletal muscle wasting, dystrophinopathy also affects non-skeletal muscle tissues, including cells in the cardio-respiratory system, the central nervous system, the liver and the kidney.Areas covered: This review summarizes the proteomic characterization of a key class of lipid chaperones, the large family of fatty acid binding proteins, and their potential role in muscular dystrophy. Recent proteomic surveys using animal models and patient specimens are reviewed. Pathobiochemical changes in specific proteoforms of fatty acid binding protein in the multi-system pathology of dystrophinopathy are discussed.Expert opinion: The mass spectrometric identification of distinct changes in fatty acid binding proteins in muscle, heart, liver, kidney and serum demonstrates that considerable alterations occur in key steps of metabolite transport and fat metabolism in muscular dystrophy. These new findings might be helpful to further develop a comprehensive biomarker signature of metabolic changes in X-linked muscular dystrophy, which should improve (i) our understanding of complex pathobiochemical changes due to dystrophin deficiency, (ii) the identification of novel therapeutic targets, and (iii) the design of differential diagnostic, prognostic and therapy-monitoring approaches.