Amyotrophic lateral sclerosis (ALS) is a paralytic and usually fatal disorder caused by motor-neuron degeneration in the brain and spinal cord. Most cases of ALS are sporadic but about 5-10% are ...familial. Mutations in superoxide dismutase 1 (SOD1), TAR DNA-binding protein (TARDBP, also known as TDP43) and fused in sarcoma (FUS, also known as translocated in liposarcoma (TLS)) account for approximately 30% of classic familial ALS. Mutations in several other genes have also been reported as rare causes of ALS or ALS-like syndromes. The causes of the remaining cases of familial ALS and of the vast majority of sporadic ALS are unknown. Despite extensive studies of previously identified ALS-causing genes, the pathogenic mechanism underlying motor-neuron degeneration in ALS remains largely obscure. Dementia, usually of the frontotemporal lobar type, may occur in some ALS cases. It is unclear whether ALS and dementia share common aetiology and pathogenesis in ALS/dementia. Here we show that mutations in UBQLN2, which encodes the ubiquitin-like protein ubiquilin 2, cause dominantly inherited, chromosome-X-linked ALS and ALS/dementia. We describe novel ubiquilin 2 pathology in the spinal cords of ALS cases and in the brains of ALS/dementia cases with or without UBQLN2 mutations. Ubiquilin 2 is a member of the ubiquilin family, which regulates the degradation of ubiquitinated proteins. Functional analysis showed that mutations in UBQLN2 lead to an impairment of protein degradation. Therefore, our findings link abnormalities in ubiquilin 2 to defects in the protein degradation pathway, abnormal protein aggregation and neurodegeneration, indicating a common pathogenic mechanism that can be exploited for therapeutic intervention.
Objective
Determine toxicity and efficacy of autologous hematopoietic stem cell transplantation (HSCT) for patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) who are ...dependent on intravenous immunoglobulins or plasmapheresis.
Methods
Unselected peripheral blood stem cells were re-infused on day 0 after conditioning with cyclophosphamide 200 mg/kg/intravenously (IV), rATG (thymoglobulin) 5.5 mg/kg/IV, and rituximab 1000 mg/IV.
Results
Sixty-six patients underwent HSCT for CIDP. Data on sixty patients with a mean follow-up of 4.5 years (range 2–5 years) were available for analysis. There were no treatment-related deaths, and overall survival was 97%. Post-transplant immune medication-free remission was 80%, 78%, 76% 78%, and 83% at 1, 2, 3, 4, and 5 years. Ambulation without assistance improved from 33% pre-HSCT to 82% 82%, 81%, 86%, and 83% at 1, 2, 3, 4, and 5 years, respectively. Mean right/left hand grip strength (kg) improved significantly (all
p
values < 0.01) from 18.1/16.5 pre-HSCT to 26.3/25.4, 29.2/28.2, 28.8/28.6, 30.3/25.5, and 30.8/29.1 at 1, 2, 3, 4, and 5 years, respectively. Average nerve conduction velocity (NCV) (m/s) improved significantly (all
p
values ≤ 0.001) from a mean of 27.2 pre-HSCT to 33.5, 33.8, 37.7, 38.2, and 38.3 at 1, 2, 3, 4, and 5 years, respectively. Average compound motor action potential (CMAP) (mv) improved significantly (
p
values ≤ 0.001) from a mean of 3.6 pre-HSCT to 4.6, 4.6, 5.0, 5.1, and 4.1 at 1, 2, 3, 4, and 5 years, respectively.
Conclusion
A randomized trial is indicated to verify these results and confirm that HSCT reverses disability and offers long-term immune therapy independence.
Objective
Amyotrophic lateral sclerosis (ALS) is a fatal disorder of motor neuron degeneration. Most cases of ALS are sporadic (SALS), but about 5 to 10% of ALS cases are familial (FALS). Recent ...studies have shown that mutations in FUS are causal in approximately 4 to 5% of FALS and some apparent SALS cases. The pathogenic mechanism of the mutant FUS‐mediated ALS and potential roles of FUS in non‐FUS ALS remain to be investigated.
Methods
Immunostaining was performed on postmortem spinal cords from 78 ALS cases, including SALS (n = 52), ALS with dementia (ALS/dementia, n = 10), and FALS (n = 16). In addition, postmortem brains or spinal cords from 22 cases with or without frontotemporal lobar degeneration were also studied. In total, 100 cases were studied.
Results
FUS‐immunoreactive inclusions were observed in spinal anterior horn neurons in all SALS and FALS cases, except for those with SOD1 mutations. The FUS‐containing inclusions were also immunoreactive with antibodies to TDP43, p62, and ubiquitin. A fraction of tested FUS antibodies recognized FUS inclusions, and specific antigen retrieval protocol appeared to be important for detection of the skein‐like FUS inclusions.
Interpretation
Although mutations in FUS account for only a small fraction of FALS and SALS, our data suggest that FUS protein may be a common component of the cellular inclusions in non‐SOD1 ALS and some other neurodegenerative conditions, implying a shared pathogenic pathway underlying SALS, non‐SOD1 FALS, ALS/dementia, and related disorders. Our data also indicate that SOD1‐linked ALS may have a pathogenic pathway distinct from SALS and other types of FALS. ANN NEUROL 2010;67:739–748
Objective: To assess safety and define efficacy measures of hepatocyte growth factor (HGF) DNA plasmid, VM202, administered by intramuscular injections in patients with amyotrophic lateral sclerosis ...(ALS).
Methods: Eighteen participants were treated with VM202 administered in divided doses by injections alternating between the upper and lower limbs on d 0, 7, 14, and 21. Subjects were followed for nine months to evaluate possible adverse events. Functional outcome was assessed using the ALS Functional Rating Scale-Revised (ALSFRS-R) as well as by serially measuring muscle strength, muscle circumference, and forced vital capacity.
Results: Seventeen of 18 participants completed the study. All participants tolerated 64 mg of VM202 well with no serious adverse events (SAE) related to the drug. Twelve participants reported 26 mild or moderate injection site reactions. Three participants experienced five SAEs unrelated to VM202. One subject died from respiratory insufficiency secondary to ALS progression.
Conclusions: Multiple intramuscular injection of VM202 into the limbs appears safe in ALS subjects. Future trials with retreatment after three months will determine whether VM202 treatment alters the long-term course of ALS.
Background Mitochondrial abnormalities exist in gastrocnemius muscle of people with peripheral artery disease (PAD). Whether abnormalities in mitochondrial biogenesis and autophagy are associated ...with greater ischemia or walking impairment in PAD is unknown. Methods and Results Protein markers of mitochondrial biogenesis and autophagy and the abundance of mitochondrial electron transport chain complexes were quantified in gastrocnemius muscle biopsies from people with and without PAD. Their 6-minute walk distance and 4-m gait speed were measured. Sixty-seven participants (mean age 65.0 years ±6.8, 16 23.9% women, 48 71.6% Black) were enrolled, including 15 with moderate to severe PAD (ankle brachial index ABI <0.60), 29 with mild PAD (ABI 0.60-0.90), and 23 without PAD (ABI 1.00-1.40). Abundance of all electron transport chain complexes was significantly higher in participants with lower ABI (eg, complex I: 0.66, 0.45, 0.48 arbitrary units AU, respectively,
trend=0.043). Lower ABI values were associated with a higher LC3A/B II-to-LC3A/B I (microtubule-associated protein 1A/1B-light chain 3) ratio (2.54, 2.31, 2.15 AU, respectively,
trend=0.017) and reduced abundance of the autophagy receptor p62 (0.71, 0.69, 0.80 AU, respectively,
trend=0.033). The abundance of each electron transport chain complex was positively and significantly associated with 6-minute walk distance and 4-m gait speed at usual and fast pace only among participants without PAD (eg, complex I:
=0.541,
=0.008;
=0.477,
=0.021;
=0.628,
=0.001, respectively). Conclusions These results suggest that accumulation of electron transport chain complexes in gastrocnemius muscle of people with PAD may be because of impaired mitophagy in the setting of ischemia. Findings are descriptive, and further study in larger sample sizes is needed.
Background Peripheral artery disease (PAD) is a manifestation of atherosclerosis characterized by reduced blood flow to the lower extremities and mobility loss. Preliminary evidence suggests PAD ...damages skeletal muscle, resulting in muscle impairments that contribute to functional decline. We sought to determine whether PAD is associated with an altered macrophage profile in gastrocnemius muscles and whether muscle macrophage populations are associated with impaired muscle phenotype and walking performance in patients with PAD. Methods and Results Macrophages, satellite cells, and extracellular matrix in gastrocnemius muscles from 25 patients with PAD and 7 patients without PAD were quantified using immunohistochemistry. Among patients with PAD, both the absolute number and percentage of cluster of differentiation (CD) 11b+CD206+ M2-like macrophages positively correlated to satellite cell number (
=0.461
=0.023 and
=0.416
=0.042, respectively) but not capillary density or extracellular matrix. The number of CD11b+CD206- macrophages negatively correlated to 4-meter walk tests at normal (
=-0.447,
=0.036) and fast pace (
=-0.510,
=0.014). Extracellular matrix occupied more muscle area in PAD compared with non-PAD (8.72±2.19% versus 5.30±1.03%,
<0.001) and positively correlated with capillary density (
=0.656,
<0.001). Conclusions Among people with PAD, higher CD206+ M2-like macrophage abundance was associated with greater satellite cell numbers and muscle fiber size. Lower CD206- macrophage abundance was associated with better walking performance. Further study is needed to determine whether CD206+ macrophages are associated with ongoing reparative processes enabling skeletal muscle adaptation to damage with PAD. Registration URL: https://www.clinicaltrials.gov; Unique identifiers: NCT00693940, NCT01408901, NCT0224660.
Background Peripheral artery disease (PAD) is associated with gastrocnemius muscle abnormalities. However, the biological pathways associated with gastrocnemius muscle dysfunction and their ...associations with progression of PAD are largely unknown. This study characterized differential gene and microRNA (miRNA) expression in gastrocnemius biopsies from people without PAD compared with those with PAD. Participants with PAD included those with and without PAD progression. Methods and Results mRNA and miRNA sequencing were performed to identify differentially expressed genes, differentially expressed miRNAs, mRNA-miRNA interactions, and associated biological pathways for 3 sets of comparisons: (1) PAD progression (n=7) versus non-PAD (n=7); (2) PAD no progression (n=6) versus non-PAD; and (3) PAD progression versus PAD no progression. Immunohistochemistry was performed to determine gastrocnemius muscle fiber types and muscle fiber size. Differentially expressed genes and differentially expressed miRNAs were more abundant in the comparison of PAD progression versus non-PAD compared with PAD with versus without progression. Among the top significant cellular pathways in subjects with PAD progression were muscle contraction or development, transforming growth factor-beta, growth/differentiation factor, and activin signaling, inflammation, cellular senescence, and notch signaling. Subjects with PAD progression had increased frequency of smaller Type 2a gastrocnemius muscle fibers in exploratory analyses. Conclusions Humans with PAD progression exhibited greater differences in the number of gene and miRNA expression, biological pathways, and Type 2a muscle fiber size compared with those without PAD. Fewer differences were observed between people with PAD without progression and control patients without PAD. Further study is needed to confirm whether the identified transcripts may serve as potential biomarkers for diagnosis and progression of PAD.
Background Patients with peripheral artery disease (PAD) undergo frequent episodes of ischemia-reperfusion in lower extremity muscles that may negatively affect mitochondrial health and are ...associated with impaired mobility. We hypothesized that skeletal muscle from PAD patients will show high mitochondrial DNA heteroplasmy, especially in regions more susceptible to oxidative damage, such as the displacement loop, and that the degree of heteroplasmy will be correlated with the severity of ischemia and mobility impairment. Methods and Results Mitochondrial mutations and deletions and their relative abundance were identified by targeted mitochondrial DNA sequencing in biopsy specimens of gastrocnemius muscle from 33 PAD (ankle brachial index <0.9) and 9 non-PAD (ankle brachial index >0.9) subjects aged ≥60 years. The probability of heteroplasmy per DNA base was significantly higher for PAD subjects than non-PAD within each region. In adjusted models, PAD was associated with higher heteroplasmy than non-PAD (
=0.003), but the association was limited to microheteroplasmy, that is heteroplasmy found in 1% to 5% of all mitochondrial genomes (
=0.004). Heteroplasmy in the displacement loop and coding regions were significantly higher for PAD than non-PAD subjects after adjustment for age, sex, race, and diabetes mellitus (
=0.037 and 0.004, respectively). Low mitochondrial damage, defined by both low mitochondrial DNA copy number and low microheteroplasmy, was associated with better walking performance. Conclusions People with PAD have higher "low frequency" heteroplasmy in gastrocnemius muscle compared with people without PAD. Among people with PAD, those who had evidence of least mitochondrial damage, had better walking performance than those with more mitochondrial damage. Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02246660.
Abstract People with lower extremity peripheral artery disease (PAD) have increased oxidative stress, impaired mitochondrial activity, and poor walking performance. NAD+ reduces oxidative stress and ...is an essential cofactor for mitochondrial respiration. Oral nicotinamide riboside (NR) increases bioavailability of NAD+ in humans. Among 90 people with PAD, this randomized double-blind clinical trial assessed whether 6-months of NR, with and without resveratrol, improves 6-min walk distance, compared to placebo, at 6-month follow-up. At 6-month follow-up, compared to placebo, NR significantly improved 6-min walk (+7.0 vs. −10.6 meters, between group difference: +17.6 (90% CI: + 1.8,+∞). Among participants who took at least 75% of study pills, compared to placebo, NR improved 6-min walk by 31.0 meters and NR + resveratrol improved 6-min walk by 26.9 meters. In this work, NR meaningfully improved 6-min walk, and resveratrol did not add benefit to NR alone in PAD. A larger clinical trial to confirm these findings is needed.
Patients with lower extremity peripheral artery disease (PAD) have decreased mobility, which is not fully explained by impaired blood supply to the lower limb. Additionally, reports are conflicted ...regarding fiber type distribution patterns in PAD, but agree that skeletal muscle mitochondrial respiration is impaired.
To test the hypothesis that reduced muscle fiber oxidative activity and type I distribution are negatively associated with walking performance in PAD, calf muscle biopsies from non-PAD (n = 7) and PAD participants (n = 26) were analyzed immunohistochemically for fiber type and size, oxidative activity, markers of autophagy, and capillary density. Data were analyzed using analysis of covariance.
There was a wide range in fiber type distribution among subjects with PAD (9-81 % type I fibers) that did not correlate with walking performance. However, mean type I fiber size correlated with 4-min normal- and fastest-paced walk velocity (r = 0.4940, P = 0.010 and r = 0.4944, P = 0.010, respectively). Although intensity of succinate dehydrogenase activity staining was consistent with fiber type, up to 17 % of oxidative fibers were devoid of mitochondria in their cores, and the core showed accumulation of the autophagic marker, LC3, which did not completely co-localize with LAMP2, a lysosome marker.
Calf muscle type I fiber size positively correlates with walking performance in PAD. Accumulation of LC3 and a lack of co-localization of LC3 with LAMP2 in the area depleted of mitochondria in PAD fibers suggests impaired clearance of damaged mitochondria, which may contribute to reduced muscle oxidative capacity. Further study is needed to determine whether defective mitophagy is associated with decline in function over time, and whether interventions aimed at preserving mitochondrial function and improving autophagy can improve walking performance in PAD.
PDF
