The effect of video-guidance on passive movement in patients with cerebral palsy: fMRI study

In patients with cerebral palsy (CP), neuroimaging studies have demonstrated that passive movement and action-observation tasks have in common to share neuronal activation in all or part of areas involved in motor system. Action observation with simultaneous congruent passive movements may have additional effects in the recruitment of brain motor areas. The aim of this functional magnetic resonance imaging (fMRI) study was to examine brain activation in patients with unilateral CP during passive movement with and without simultaneous observation of simple hand movement. Eighteen patients with unilateral CP (fourteen male, mean age 14 years and 2 months) participated in the study. Using fMRI block design, brain activation following passive simple opening-closing hand movement of either the paretic or nonparetic hand with and without simultaneous observation of a similar movement performed by either the left or right hand of an actor was compared. Passive movement of the paretic hand performed simultaneously to the observation of congruent movement activated more "higher motor areas" including contralesional pre-supplementary motor area, superior frontal gyrus (extending to premotor cortex), and superior and inferior parietal regions than nonvideo-guided passive movement of the paretic hand. Passive movement of the paretic hand recruited more ipsilesional sensorimotor areas compared to passive movement of the nonparetic hand. Our study showed that the combination of observation of congruent hand movement simultaneously to passive movement of the paretic hand recruits more motor areas, giving neuronal substrate to propose video-guided passive movement of paretic hand in CP rehabilitation.

Restriction of calpain3 expression to the skeletal muscle prevents cardiac toxicity and corrects pathology in a murine model of limb-girdle muscular dystrophy

BACKGROUND

Genetic defects in calpain3 (CAPN3) lead to limb-girdle muscular dystrophy type 2A, a disease of the skeletal muscle that affects predominantly the proximal limb muscles. We previously demonstrated the potential of adeno-associated virus-mediated transfer of the CAPN3 gene to correct the pathological signs in a murine model for limb-girdle muscular dystrophy type 2A after intramuscular and locoregional administrations.

METHODS AND RESULTS

Here, we showed that intravenous injection of calpain3-expressing vector in mice can induce mortality in a dose-dependent manner. An anatomopathological investigation revealed large areas of fibrosis in the heart that we related to unregulated proteolytic activity of calpain3. To circumvent this toxicity, we developed new adeno-associated virus vectors with skeletal muscle-restricted expression by using new muscle-specific promoters that include the CAPN3 promoter itself and by introducing a target sequence of the cardiac-specific microRNA-208a in the cassette. Our results show that CAPN3 transgene expression can be successfully suppressed in the cardiac tissue, preventing the cardiac toxicity, whereas expression of the transgene in skeletal muscle reverts the pathological signs of calpain3 deficiency.

CONCLUSIONS

The molecular strategies used in this study may be useful for any gene transfer strategy with potential toxicity in the heart.

Post-acute assessment programme for patients with traumatic brain injury: measuring the gap between patients' expectations on entering and end of programme recommendations

OBJECTIVE

To compare the expectations of patients with brain injury (TBI) entering a post-acute programme to the recommendations made at the end.

DESIGN

Retrospective study (1997 and 2009).

INTERVENTION

This 12-week post-acute programme included ecological multidisciplinary assessment of physical and cognitive disabilities, independence in activities of daily living and work abilities. Recommendations made at the conclusion of the programme included advice regarding the ability to work in an unsheltered or a sheltered environment and possible social activities.

RESULTS

Two hundred and forty patients participated. The main objective of 95.8% was return-to-work: 93.7% expected a normal work environment, 2.1% considered a sheltered environment and 4% entered the programme with the aim of improving social abilities and integration in the community. The recommendations included return-to-work in 68.3% of cases, in an unsheltered environment in 44.2% and in a sheltered environment in 24.1% and advice for contact with social services in order to achieve better social integration in 31.7%. There was a discrepancy between expectations and recommendations in half of the cases.

CONCLUSION

The discrepancy between patients' expectations and recommendations is in part due to the cognitive disorders; long-term rehabilitation programmes should focus on this issue.

Effect of observation of simple hand movement on brain activations in patients with unilateral cerebral palsy: an fMRI study

The aim of this functional magnetic resonance imaging (fMRI) study was to examine and compare brain activation in patients with unilateral cerebral palsy (CP) during observation of simple hand movement performed by the paretic and nonparetic hand. Nineteen patients with clinical unilateral CP (14 male, mean age 14 years, 7-21 years) participated in the study. Hand motor impairment was assessed using the sequential finger opposition task. Using fMRI block design, brain activation was examined following observation at rest of a simple opening-closing hand movement, performed by either the left or right hand of an actor. Eighteen fMRI dataset were analyzed. Observing hand movement produced large bilateral activations in temporo-parieto-fronto-occipital network, comprising most of the nodes of the well described action-observation network. For either side, observing hand movements recruits the primary motor cortex (M1), contralateral to the viewed hand, as would be expected in healthy persons. Viewing movement performed by an actor's hand representing the paretic side of patients activated more strongly ipsilesional M1 than viewing movement performed by an actor's hand representing the nonparetic side of patients. Observation of hand movement in patients with CP engaged the motor execution network regardless of the degree of motor impairment.

The phenotype of dysferlin-deficient mice is not rescued by adeno-associated virus-mediated transfer of anoctamin 5

Mutations in dysferlin and anoctamin 5 are the cause of muscular disorders, with the main presentations as limb-girdle muscular dystrophy or Miyoshi type of distal myopathy. Both these proteins have been implicated in sarcolemmal resealing. On the basis of similarities in associated phenotypes and protein functions, we tested the hypothesis that ANO5 protein could compensate for dysferlin absence. We first defined that the main transcript of ANO5 expressed in skeletal muscle is the 22-exon full-length isoform, and we demonstrated that dysferlin-deficient (Dysf (prmd)) mice have lower Ano5 expression levels, an observation that further enhanced the rational of the tested hypothesis. We then showed that AAV-mediated transfer of human ANO5 (hANO5) did not lead to apparent toxicity in wild-type mice. Finally, we demonstrated that AAV-hANO5 injection was not able to compensate for dysferlin deficiency in the Dysf (prmd) mouse model or improve the membrane repair defect seen in the absence of dysferlin. Consequently, overexpressing hANO5 does not seem to provide a valuable therapeutic strategy for dysferlin deficiency.

Ionization behavior of chitosan and chitosan-DNA polyplexes indicate that chitosan has a similar capability to induce a proton-sponge effect as PEI

Polycations having a high buffering capacity in the endosomal pH range, such as polyethylenimine (PEI), are known to be efficient at delivering nucleic acids by overcoming lysosomal sequestration possibly through the proton sponge effect, although other mechanisms such as membrane disruption arising from an interaction between the polycation and the endosome/lysosome membrane, have been proposed. Chitosan is an efficient delivery vehicle for nucleic acids, yet its buffering capacity has been thought to be significantly lower than that of PEI, suggesting that the molecular mechanism responsible for endolysosomal escape was not proton sponge based. However, previous comparisons of PEI and chitosan buffering capacity were performed on a mass concentration basis instead of a charge concentration basis, the latter being the most relevant comparison basis because polycation-DNA complexes form at ratios of charge groups (amine to phosphate), rather than according to mass. We hypothesized that chitosan has a high buffering capacity when compared to PEI on a molar basis and could therefore possibly mediate endolysosomal release through the proton sponge effect. In this study, we examined the ionization behavior of chitosan and chitosan-DNA complexes and compared to that of PEI and polylysine on a charge concentration basis. A mean field theory based on the use of the Poisson-Boltzmann equation and an Ising model were also applied to model ionization behavior of chitosan and PEI, respectively. We found that chitosan has a higher buffering capacity than PEI in the endolysosomal pH range, while the formation of chitosan-DNA complexes reduces chitosan buffering capacity because of the negative electrostatic environment of nucleic acids that facilitates chitosan ionization. These data suggest that chitosans have a similar capacity as PEI to mediate endosomal escape through the proton sponge effect, possibly in a manner which depends on the presence of excess chitosan.

Cardiac characterization of mdx mice using high-resolution doppler echocardiography

OBJECTIVES

Duchenne muscular dystrophy is an X-linked neuromuscular disorder. The heart is traditionally involved, leading to heart failure. The mdx mouse is a natural animal model of the disease. We conducted a prospective study to analyze left ventricular (LV) function in mdx mice at different ages using high-resolution Doppler echocardiography.

METHODS

Echocardiography was performed with a 30-MHz cardiac probe. Wild-type and mdx mice were scanned at 10 and 12 months. We measured the interventricular septal wall thickness, posterior wall thickness, and LV diameter in systole and diastole. The LV shortening fraction, LV ejection fraction, and LV mass were then calculated.

RESULTS

At 10 months, the shortening fractions in mdx and wild-type mice were relatively close (29% ± 5% versus 25% ± 4%). We found a significant difference in the posterior wall thickness change (40% ± 12% in mdx versus 28% ± 10% in wild-type; P = .048). The LV mass/body weight ratio was higher in mdx than wild-type mice (3.67 ± 0.25 versus 3.39 ± 0.26; P = .05). At 12 months, the LV mass was elevated in mdx mice compared to wild-type (152 ±16 versus 135 ± 3.7 mg; P = .04). The diastolic posterior wall thickness change was decreased in mdx mice at 12 months compared to wild-type (21% ± 7% versus 33% ± 4%; P = .01). The LV ejection fraction was not statistically different between mdx and wild-type mice (50% ± 6% versus 54% ± 2%).

CONCLUSIONS

Ten-month-old mdx mice had a significantly higher posterior wall thickness than wild-type mice, but it was not significant at 12 months. In 12-month-old mdx mice, the posterior wall thickness change was significantly lower, and the LV mass was significantly higher. These findings indicate the role of LV function in the early stages of Duchenne muscular dystrophy.

A human skeletal muscle interactome centered on proteins involved in muscular dystrophies: LGMD interactome

Background

The complexity of the skeletal muscle and the identification of numerous human disease-causing mutations in its constitutive proteins make it an interesting tissue for proteomic studies aimed at understanding functional relationships of interacting proteins in both health and diseases.

Method

We undertook a large-scale study using two-hybrid screens and a human skeletal-muscle cDNA library to establish a proteome-scale map of protein-protein interactions centered on proteins involved in limb-girdle muscular dystrophies (LGMD). LGMD is a group of more than 20 different neuromuscular disorders that principally affect the proximal pelvic and shoulder girdle muscles.

Results and conclusion

The interaction network we unraveled incorporates 1018 proteins connected by 1492 direct binary interactions and includes 1420 novel protein-protein interactions. Computational, experimental and literature-based analyses were performed to assess the overall quality of this network. Interestingly, LGMD proteins were shown to be highly interconnected, in particular indirectly through sarcomeric proteins. In-depth mining of the LGMD-centered interactome identified new candidate genes for orphan LGMDs and other neuromuscular disorders. The data also suggest the existence of functional links between LGMD2B/dysferlin and gene regulation, between LGMD2C/γ-sarcoglycan and energy control and between LGMD2G/telethonin and maintenance of genome integrity. This dataset represents a valuable resource for future functional investigations.

Distinctive serum miRNA profile in mouse models of striated muscular pathologies

Biomarkers are critically important for disease diagnosis and monitoring. In particular, close monitoring of disease evolution is eminently required for the evaluation of therapeutic treatments. Classical monitoring methods in muscular dystrophies are largely based on histological and molecular analyses of muscle biopsies. Such biopsies are invasive and therefore difficult to obtain. The serum protein creatine kinase is a useful biomarker, which is however not specific for a given pathology and correlates poorly with the severity or course of the muscular pathology. The aim of the present study was the systematic evaluation of serum microRNAs (miRNAs) as biomarkers in striated muscle pathologies. Mouse models for five striated muscle pathologies were investigated: Duchenne muscular dystrophy (DMD), limb-girdle muscular dystrophy type 2D (LGMD2D), limb-girdle muscular dystrophy type 2C (LGMD2C), Emery-Dreifuss muscular dystrophy (EDMD) and hypertrophic cardiomyopathy (HCM). Two-step RT-qPCR methodology was elaborated, using two different RT-qPCR miRNA quantification technologies. We identified miRNA modulation in the serum of all the five mouse models. The most highly dysregulated serum miRNAs were found to be commonly upregulated in DMD, LGMD2D and LGMD2C mouse models, which all exhibit massive destruction of striated muscle tissues. Some of these miRNAs were down rather than upregulated in the EDMD mice, a model without massive myofiber destruction. The dysregulated miRNAs identified in the HCM model were different, with the exception of one dysregulated miRNA common to all pathologies. Importantly, a specific and distinctive circulating miRNA profile was identified for each studied pathological mouse model. The differential expression of a few dysregulated miRNAs in the DMD mice was further evaluated in DMD patients, providing new candidates of circulating miRNA biomarkers for DMD.