RESUMEN
BACKGROUND: The international Inherited Neuropathy Consortium (INC) was created with the goal of obtaining much needed natural history data for patients with Charcot-Marie-Tooth (CMT) disease. We analysed clinical and genetic data from patients in the INC to determine the distribution of CMT subtypes and the clinical impairment associated with them. METHODS: We analysed data from 1652 patients evaluated at 13 INC centres. The distribution of CMT subtypes and pathogenic genetic mutations were determined. The disease burden of all the mutations was assessed by the CMT Neuropathy Score (CMTNS) and CMT Examination Score (CMTES). RESULTS: 997 of the 1652 patients (60.4%) received a genetic diagnosis. The most common CMT subtypes were CMT1A/PMP22 duplication, CMT1X/GJB1 mutation, CMT2A/MFN2 mutation, CMT1B/MPZ mutation, and hereditary neuropathy with liability to pressure palsy/PMP22 deletion. These five subtypes of CMT accounted for 89.2% of all genetically confirmed mutations. Mean CMTNS for some but not all subtypes were similar to those previously reported. CONCLUSIONS: Our findings confirm that large numbers of patients with a representative variety of CMT subtypes have been enrolled and that the frequency of achieving a molecular diagnosis and distribution of the CMT subtypes reflects those previously reported. Measures of severity are similar, though not identical, to results from smaller series. This study confirms that it is possible to assess patients in a uniform way between international centres, which is critical for the planned natural history study and future clinical trials. These data will provide a representative baseline for longitudinal studies of CMT. CLINICAL TRIAL REGISTRATION: ID number NCT01193075.
Asunto(s)
Enfermedad de Charcot-Marie-Tooth/clasificación , Proteínas Adaptadoras Transductoras de Señales , Proteínas de Ciclo Celular , Enfermedad de Charcot-Marie-Tooth/genética , Enfermedad de Charcot-Marie-Tooth/patología , Enfermedad de Charcot-Marie-Tooth/fisiopatología , Conexinas/genética , Costo de Enfermedad , Estudios Transversales , Femenino , GTP Fosfohidrolasas/genética , Humanos , Masculino , Proteínas Mitocondriales/genética , Mutación/genética , Proteína P0 de la Mielina/genética , Proteínas de la Mielina/genética , Proteínas Nucleares , Proteínas/genética , Proteína beta1 de Unión ComunicanteRESUMEN
BACKGROUND: Charcot Marie Tooth disease (CMT) affects one in 2500 people. Genetic testing is often pursued for family planning purposes, natural history studies and for entry into clinical trials. However, identifying the genetic cause of CMT can be expensive and confusing to patients and physicians due to locus heterogeneity. METHODS: We analyzed data from more than 1000 of our patients to identify distinguishing features in various subtypes of CMT. Data from clinical phenotypes, neurophysiology, family history, and prevalence was combined to create algorithms that can be used to direct genetic testing for patients with CMT. FINDINGS: The largest group of patients in our clinic have slow motor nerve conduction velocities (MNCV) in the upper extremities. Approximately 88% of patients in this group have CMT1A. Those who had intermediate MNCV had primarily CMT1X (52.8%) or CMT1B (27.8%). Patients with very slow MNCV and delayed walking were very likely to have CMT1A (68%) or CMT1B (32%). No patients with CMT1B and very slow MNCV walked before 15 months of age. Patients with CMT2A form our largest group of patients with axonal forms of CMT. INTERPRETATION: Combining features of the phenotypic and physiology groups allowed us to identify patients who were highly likely to have specific subtypes of CMT. Based on these results, we created a series of algorithms to guide testing. A more detailed review of this data is published in Annals of Neurology (1).
Asunto(s)
Manejo de Caso/organización & administración , Enfermedad de Charcot-Marie-Tooth/diagnóstico , Enfermedad de Charcot-Marie-Tooth/genética , Pruebas Genéticas/métodos , Conducción Nerviosa , Extremidad Superior , Edad de Inicio , Algoritmos , Enfermedad de Charcot-Marie-Tooth/epidemiología , Enfermedad de Charcot-Marie-Tooth/fisiopatología , Electrodiagnóstico , Pruebas Genéticas/normas , Pruebas Genéticas/estadística & datos numéricos , Humanos , Patrón de Herencia , Neuronas Motoras/patología , Selección de Paciente , Linaje , Guías de Práctica Clínica como Asunto/normas , Prevalencia , Índice de Severidad de la Enfermedad , Extremidad Superior/inervación , Extremidad Superior/fisiopatologíaRESUMEN
Dominant mutations in ubiquitously expressed transfer RNA (tRNA) synthetase genes cause axonal peripheral neuropathy, accounting for at least six forms of Charcot-Marie-Tooth (CMT) disease. Genetic evidence in mouse and Drosophila models suggests a gain-of-function mechanism. In this study, we used in vivo, cell typespecific transcriptional and translational profiling to show that mutant tRNA synthetases activate the integrated stress response (ISR) through the sensor kinase GCN2 (general control nonderepressible 2). The chronic activation of the ISR contributed to the pathophysiology, and genetic deletion or pharmacological inhibition of Gcn2 alleviated the peripheral neuropathy. The activation of GCN2 suggests that the aberrant activity of the mutant tRNA synthetases is still related to translation and that inhibiting GCN2 or the ISR may represent a therapeutic strategy in CMT.
Asunto(s)
Enfermedad de Charcot-Marie-Tooth/metabolismo , Glicina-ARNt Ligasa/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Estrés Fisiológico , Tirosina-ARNt Ligasa/metabolismo , Factor de Transcripción Activador 4/genética , Factor de Transcripción Activador 4/metabolismo , Animales , Enfermedad de Charcot-Marie-Tooth/genética , Enfermedad de Charcot-Marie-Tooth/fisiopatología , Modelos Animales de Enfermedad , Femenino , Eliminación de Gen , Genes Dominantes , Glicina-ARNt Ligasa/genética , Masculino , Ratones , Ratones Mutantes , Neuronas Motoras/fisiología , Biosíntesis de Proteínas , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Serina-Treonina Quinasas/genética , Médula Espinal/fisiopatología , Estrés Fisiológico/efectos de los fármacos , Estrés Fisiológico/genética , Estrés Fisiológico/fisiología , Transcriptoma , Tirosina-ARNt Ligasa/genéticaRESUMEN
There has been considerable progress in developing treatments for Charcot-Marie-Tooth disease with a number of therapies either completing or nearing clinical trials. In the case of CMT1A, the commonest subtype of CMT, there have been more than five randomised, double blind placebo-controlled trials. Although these trials were negative for the primary outcome measure, considerable lessons have been learnt leading to the collection of large prospective natural history data sets with which to inform future trial design as well as the development of new and sensitive outcome measures. In this review we summarise the difficulties of conducting clinical trials in a slowly progressive disease such as CMT1A and the requirement for sensitive, reproducible and clinically relevant outcome measures. We summarise the current array of CMT specific outcome measures subdivided into clinical outcome measures, functional outcome measures, patient reported outcome measures, biomarkers of disease burden and treatment specific biomarkers of target engagement. Although there is now an array of CMT specific outcome measures, which collectively incorporate clinically relevant, sensitive and reproducible outputs, a single outcome measure incorporating all three qualities remains elusive.
Asunto(s)
Enfermedad de Charcot-Marie-Tooth/terapia , Ensayos Clínicos como Asunto , Evaluación de Resultado en la Atención de Salud , Biomarcadores/análisis , HumanosRESUMEN
The genetic neuropathies are a clinically and genetically heterogeneous group of diseases of which the most common types are Charcot-Marie-Tooth disease (CMT), the hereditary sensory and autonomic neuropathies and the distal hereditary motor neuropathies. More than 30 causative genes have been described, making an accurate genetic diagnosis increasingly possible. Although no specific therapies are yet available, research into their pathogenesis has revolutionised our understanding of the peripheral nervous system and allowed the development of rational approaches to therapy. The first therapeutic trials in CMT are currently underway. This review will suggest an approach to the diagnosis of these disorders and provide an update on new therapies.
Asunto(s)
Neuropatías Hereditarias Sensoriales y Autónomas/diagnóstico , Neuropatías Hereditarias Sensoriales y Autónomas/terapia , Neuropatía Hereditaria Motora y Sensorial/diagnóstico , Neuropatía Hereditaria Motora y Sensorial/terapia , Enfermedad de Charcot-Marie-Tooth/clasificación , Enfermedad de Charcot-Marie-Tooth/terapia , Terapia Genética , Neuropatías Hereditarias Sensoriales y Autónomas/clasificación , Neuropatías Hereditarias Sensoriales y Autónomas/genética , Neuropatía Hereditaria Motora y Sensorial/clasificación , Neuropatía Hereditaria Motora y Sensorial/genéticaRESUMEN
Mutations of myelin protein zero gene (MPZ) are found in 5% of Charcot-Marie-Tooth patients. In 2004, Shy et al. identified two main phenotypes associated with them: an early-onset subtype with mainly demyelinating features and a late-onset subgroup with prominent axonal impairment. We evaluated whether novel MPZ mutations described in literature during the last 14 years could still fit with this classification. We collected and revised reports of 69 novel MPZ mutations. Almost 90% of them could be alternatively classified as responsible for: (a) an early-onset phenotype, with first limitations starting before 3 years (2.5 ± 0.50 years), motor milestones delays, frequently severe course and upper limb MNCVs below 15 m/s; (b) late-onset neuropathy, with mean age of onset of 42.8 ± 1.5 years and mean upper limbs motor nerve conduction velocities (MNCVs) of 47.2 ± 1.4 m/s; (c) a phenotype more similar to typical CMT1A neuropathy, with onset during the 2nd decade, MNCV in the range of 15-30 m/s and slowly progressive course. The present work confirms that P0-related neuropathies may be separated into two main distinct phenotypes, while a third, relatively small, group comprehend patients carrying MPZ mutations and a childhood-onset disease, substantiating the subdivision into three groups proposed by Sanmaneechai et al. (Brain 138:3180-3192, 2015). Interestingly, during the last years, an increasing number of novel MPZ mutations causing a late-onset phenotype has been described, highlighting the clinical relevance of late-onset P0 neuropathies. Since the family history for neuropathy is often uncertain, due to the late disease onset, the number of patients carrying this genotype is probably underestimated.
Asunto(s)
Enfermedad de Charcot-Marie-Tooth/genética , Proteína P0 de la Mielina/genética , Edad de Inicio , Humanos , Mutación , FenotipoRESUMEN
Charcot-Marie-Tooth disease type 1A (CMT1A) is the more frequent cause of demyelinating CMT, and CMT2A is the most common cause of axonal CMT. We conducted a magnetic resonance imaging (MRI) study on 39 CMT1A and 21 CMT2A patients to compare their neuroimaging patterns and correlate with clinical features. CMT1A patients showed selective fatty infiltration with a preference for anterior and lateral compartment muscles, whereas CMT2A patients showed a preference for superficial posterior compartment muscles. Early-onset CMT2A patients showed more severe leg fatty atrophy than late-onset CMT2A patients. In late-onset CMT2A, soleus muscle was the earliest, and most severely affected than the other leg muscles. Selective involvement of intrinsic foot muscles is a characteristic pattern of minimal CMT1A and CMT2A. Our MRI study demonstrates different patterns of fatty infiltration involving superficial posterior compartment muscles in CMT2A (partial T-type), and peroneal nerve innervated muscles in CMT1A (P-type).
Asunto(s)
Enfermedad de Charcot-Marie-Tooth/clasificación , Enfermedad de Charcot-Marie-Tooth/patología , Tejido Adiposo/patología , Adolescente , Adulto , Edad de Inicio , Anciano , Atrofia , Enfermedad de Charcot-Marie-Tooth/genética , Niño , Preescolar , ADN/genética , Edema/patología , Femenino , Pie/patología , Duplicación de Gen , Humanos , Extremidad Inferior/patología , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Fuerza Muscular/genética , Fuerza Muscular/fisiología , Músculo Esquelético/patología , Mutación/genética , Mutación/fisiologíaRESUMEN
In a previous report, we demonstrated that a first-generation (E1- and E3-deleted) recombinant adenovirus can transduce expression of the E. coli lacZ gene into Schwann cells, both in vitro and in vivo, suggesting that this method might be useful for future therapy of peripheral neuropathy, including CMT1. Adenovirus-mediated gene transfer was limited, however, by demyelination and Wallerian degeneration at the site of virus injection, as well as by attenuation of viral transgene expression over time. In our current work we have optimized adenoviral vector-mediated transgene expression after intraneural injection into sciatic nerve. Using an improved injection protocol, peak expression of lacZ occurs between 10 and 14 days after injection of 2-week-old rats, decreases thereafter, and there is minimal associated tissue injury. In contrast, few lacZ-expressing Schwann cells are found in nerve of adult animals 10 days after injection, probably owing to immune clearance of virus-infected cells. Consistent with this notion, high levels of LacZ are found in sciatic nerve 30 days after injection of adult SCID mice, which have a genetic defect in both cellular and humoral immunity, of adult beta2-microglobulin-deficient mice (beta2M4-/-), which have a genetic defect in cellular immunity, or of adult mice treated with the immunosuppressing agent FK506. In addition, adenovirus-infected Schwann cells cocultured with axons in vitro, in the absence of a host immune response, ensheathe axons and express lacZ for at least 8 weeks. These data thus demonstrate that lacZ transgene expression of first-generation recombinant adenovirus in sciatic nerve in adult mice, as in other tissues, is limited mainly by the host cellular immune response to the virus, which can be overcome by attenuation of host cell-mediated immunity. Adenoviral vectors might thus be used to modulate Schwann cell gene expression in patients with peripheral neuropathy after appropriate immunosuppression.
Asunto(s)
Técnicas de Transferencia de Gen , Inmunidad Celular/fisiología , Nervio Ciático/metabolismo , Adenoviridae/genética , Factores de Edad , Animales , Compuestos Azo/metabolismo , Southern Blotting , Colorantes/metabolismo , Cartilla de ADN , Vectores Genéticos , Inmunohistoquímica , Inmunosupresores/farmacología , Operón Lac , Mediciones Luminiscentes , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones SCID , Naftalenos , Plásmidos , Ratas , Ratas Sprague-Dawley , Células de Schwann/citología , Células de Schwann/metabolismo , Nervio Ciático/anatomía & histología , Tacrolimus/farmacología , Factores de Tiempo , beta-Galactosidasa/metabolismoRESUMEN
Demyelinating peripheral neuropathies are clinically divided into inherited and acquired types. Inherited demyelinating neuropathies are caused by mutations in genes expressed by myelinating Schwann cells, whereas acquired ones, including chronic inflammatory demyelinating polyneuropathy (CIDP), are probably caused by autoimmune mechanisms. We find that heterozygous P0 knockout (P0+/-) mice develop a neuropathy that resembles CIDP. By one year of age, P0+/- mice develop severe, asymmetric slowing of motor nerves, with temporal dispersion or conduction block, which are features of acquired demyelinating neuropathies including CIDP. Moreover, morphological analysis of affected nerves reveals severe and selective demyelination of motor fibers, focal regions of demyelination, and inflammatory cells. These data suggest that immune-mediated mechanisms may contribute to the pathogenesis of the neuropathy in P0+/- mice.
Asunto(s)
Enfermedades Desmielinizantes/patología , Modelos Animales de Enfermedad , Ratones Noqueados/genética , Potenciales de Acción , Envejecimiento/patología , Envejecimiento/fisiología , Animales , Enfermedad Crónica , Enfermedades Desmielinizantes/genética , Enfermedades Desmielinizantes/fisiopatología , Inflamación/patología , Ratones , Conducción Nerviosa , Nervio Ciático/patología , Nervio Ciático/fisiopatología , Factores de TiempoRESUMEN
Patients with motor neuron disease with thyroid disorders have been described, although the relationship between the two conditions is unclear. We treated a patient with amyotrophic lateral sclerosis who also had a follicular adenoma of the thyroid gland. Because thyroid gland plasma membranes contain high concentrations of complex gangliosides, such as GD1b, and some patients with motor neuron disease have IgM antibodies to GD1b, we decided to assay serum from this patient for the presence of antiganglioside antibodies. IgM antibodies to GD1b were detectable at serum dilutions of 1:500 and 1:1000 by enzyme-linked immunosorbent assay. While these titers are less than those usually described in patients with plasma cell dyscrasia, they are well in excess of normal values. Antibody to GM1 was also detectable at a lower (1:100) dilution. We do not know the importance of the anti-GD1b antibodies in this patient, but it is possible that antibodies to GD1b are involved in this and other cases of motor neuron disease associated with thyroid disease.
Asunto(s)
Adenoma/inmunología , Esclerosis Amiotrófica Lateral/inmunología , Anticuerpos/análisis , Gangliósidos/inmunología , Neoplasias de la Tiroides/inmunología , Adenoma/complicaciones , Esclerosis Amiotrófica Lateral/complicaciones , Gangliósido G(M1)/inmunología , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Tiroides/complicacionesRESUMEN
We report three patients who developed chronic inflammatory demyelinating polyneuropathy (CIDP) in association with malignant melanoma. In two cases, melanoma was discovered during the initial evaluation for neuropathy. Two patients also had vitiligo, an antibody-mediated disorder that may complicate melanoma. Melanoma cells and Schwann cells are both of neuroectodermal cell origin, with shared surface antigens. Shared immunoreactivity may account for the association between melanoma and CIDP, as with vitiligo.
Asunto(s)
Enfermedades Desmielinizantes/complicaciones , Enfermedades Linfáticas/complicaciones , Melanoma/complicaciones , Enfermedades del Sistema Nervioso Periférico/complicaciones , Adulto , Enfermedad Crónica , Humanos , Ganglios Linfáticos/patología , Enfermedades Linfáticas/patología , Masculino , Melanoma/patología , Persona de Mediana Edad , Vitíligo/complicacionesRESUMEN
IgM lambda monoclonal antibodies in two patients with motor neuron disease showed the same unique antigenic specificity. They bound to gangliosides GM1 and GD1b and to lacto-N-tetraose-BSA. By immunofluorescence microscopy they bound to central and peripheral nerve tissue and to motor end-plates at the neuromuscular junction. Sera from control subjects did not contain antibodies of similar specificity. Monoclonal IgMs with the same unique specificity could be responsible for motor neuron disease in some patients with monoclonal gammopathies.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Gangliósidos/inmunología , Inmunoglobulina M/inmunología , Neuronas Motoras , Enfermedades Neuromusculares/enzimología , Oligosacáridos/inmunología , Autoanticuerpos/inmunología , Epítopos , Femenino , Técnica del Anticuerpo Fluorescente , Gangliósido G(M1)/inmunología , Humanos , Masculino , Persona de Mediana Edad , Tejido Nervioso/inmunologíaRESUMEN
We followed a patient with a lower motor neuron form of motor neuron disease whose neurologic disorder improved following immunotherapy. The patient did not have an M protein but did have IgM antibodies to ganglioside GM1 detectable at serum titers of 1:2,000 by ELISA. These antibodies were found only in the IgM fraction with lambda light chains and immunoreacted with GD1b and Gal (beta 1-3) GalNAc.
Asunto(s)
Antígenos de Carbohidratos Asociados a Tumores , Autoanticuerpos/análisis , Disacáridos/inmunología , Gangliósido G(M1)/inmunología , Gangliósidos/inmunología , Inmunoglobulina M/análisis , Inmunoterapia , Neuronas Motoras/inmunología , Enfermedades Neuromusculares/inmunología , Adulto , Cromatografía Líquida de Alta Presión/métodos , Ensayo de Inmunoadsorción Enzimática , Humanos , Masculino , Enfermedades Neuromusculares/terapiaRESUMEN
In the years 1977 to 1984, 10 of 206 patients (4.8%) with motor neuron disease (MND) had M proteins; 4 had IgM and 6 had IgG. Among 100 control patients with other neurologic diseases, only 1 had an M protein. We later added six cases of MND and M proteins, as well as three with polyclonal IgM elevations and two with Bence-Jones proteins. Including other reports, there are now 37 known cases of MND with monoclonal and 5 with polyclonal gammopathy. There is evidence that plasma cell dyscrasia is often undetected; the actual incidence of serum immunoglobulin abnormality in patients with MND may be greater than our figure.
Asunto(s)
Esclerosis Amiotrófica Lateral/diagnóstico , Neuronas Motoras , Atrofia Muscular/complicaciones , Paraproteinemias/complicaciones , Adolescente , Adulto , Anciano , Esclerosis Amiotrófica Lateral/complicaciones , Femenino , Glicoproteínas/análisis , Humanos , Inmunoglobulina G/análisis , Inmunoglobulina M/análisis , Masculino , Persona de Mediana Edad , Atrofia Muscular/diagnóstico , Paraproteinemias/diagnósticoRESUMEN
Some patients with neuropathy have IgM M-proteins that bind to myelin and to myelin-associated glycoprotein (MAG). We compared the binding properties of a human anti-MAG M-protein with three mouse monoclonal anti-MAG antibodies (GEN-S1, GEN-S3, GEN-S8) and with a mouse monoclonal antibody (HNK-1) that binds to both MAG and to human natural killer cells. The antibodies GEN-S1, GEN-S3, and GEN-S8 bound to different epitopes in the polypeptide portion of MAG as shown by peptide mapping, deglycosylation and competitive binding studies. The M-protein and HNK-1 bound to both CNS and PNS MAG and to several additional protein bands of 70K, 30K, 26K, and 23K daltons in peripheral, but not in central myelin; they did not bind to deglycosylated MAG. The M-protein and HNK-1 immunostained myelin diffusely, whereas GEN-S8 immunostained only the periaxonal and outer regions of myelin sheath, and there was no staining with GEN-S1 or GEN-S3. The human M-proteins probably bind to a carbohydrate moiety in MAG that is also present in other PNS myelin proteins. This may explain the observed differences in immunostaining and the sparing of the CNS in patients with anti-MAG M-proteins.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Epítopos , Proteínas de la Mielina/inmunología , Animales , Humanos , Ratones , Ratones Endogámicos BALB C , Glicoproteína Asociada a MielinaRESUMEN
In some patients with neuropathy and IgM M-proteins the M-proteins bind to a carbohydrate determinant that is shared by the CNS and PNS myelin-associated glycoprotein (MAG) and by several additional glycoproteins and 2 glycolipids in peripheral nerve. The HNK-1 mouse monoclonal antibody binds to the same glycoproteins and glycolipids as well as to a number of other neuronal adhesion molecules and to human natural killer cells. To isolate the epitope-bearing oligosaccharides from their respective glycoproteins we digested delipidated spinal cord and peripheral nerve with pronase. The resulting glycopeptides were fractionated by concanavalin A-Sepharose chromatography to yield tri- and tetraantennary-complex, biantennary-complex and high mannose-type glycopeptides. Glycopeptides bearing the antigenic determinant were identified by their ability to block binding of M-proteins and HNK-1 antibodies to MAG-coated microwells by enzyme-linked immunosorbent assay (ELISA). Blocking activity was detected in the tri- and tetraantennary glycopeptide fraction from both CNS and PNS. The blocking activity was destroyed by pretreatment of the isolated glycopeptides with mild acid hydrolysis. Further fractionation by gel filtration chromatography indicated that the reactive glycopeptides from peripheral nerve and spinal cord eluted in the same position. The data suggest that CNS and PNS MAG and other peripheral nerve glycoproteins share similar oligosaccharides, and that the M-proteins and HNK-1 bind to the same structures.
Asunto(s)
Anticuerpos Monoclonales/metabolismo , Proteínas Sanguíneas/metabolismo , Enfermedades Desmielinizantes/metabolismo , Glicoproteínas/análisis , Inmunoglobulinas , Proteínas de la Mielina/inmunología , Oligosacáridos/metabolismo , Animales , Anticuerpos Monoclonales/inmunología , Proteínas Sanguíneas/inmunología , Química Encefálica , Humanos , Ratones , Glicoproteína Asociada a Mielina , Oligosacáridos/aislamiento & purificación , Nervios Periféricos/análisis , Médula Espinal/análisisRESUMEN
In a previous report, we demonstrated that a first generation (E1- and E3-deleted) recombinant adenovirus can transduce expression of the E. coli lacZ gene into Schwann cells, both in vitro and in vivo, suggesting that this method might be useful for future therapy of peripheral neuropathy, including CMT1. Adenoviral-mediated gene transfer was limited, however, by demyelination and Wallerian degeneration at the site of virus injection, as well as by attenuation of viral gene expression over time. In our current work we have optimized adenoviral-mediated gene expression after intraneural injection into sciatic nerve. Using an improved injection protocol, peak expression of lacZ occurs between 10 and 14 days after injection of 2-week-old animals, decreases thereafter, and there is minimal associated tissue injury. In contrast, very few adenoviral-infected Schwann cells are found in nerves of adult animals 10 days after injection, probably due to immune clearance of viral-infected cells. Consistent with this notion, high levels of lacZ are found in sciatic nerve 30 days after injection of adult SCOD mice, which have a genetic defect in both cellular and humoral immunity, of adult beta 2 microglobulin-deficient mice (beta 2 M-/-), which have a genetic defect in cellular immunity, or of adult mice treated with the immunosuppressing agent FK506. In addition, adenoviral-infected Schwann cells co-cultured with axons in vitro, in the absence of a host immune response, ensheath axons and express lacZ for at least 8 weeks. These data thus demonstrate that expression of first generation recombinant adenovirus in sciatic nerve in adult mice, as in other tissues, is limited mainly by the host cellular immune response to the virus, which can be overcome by attenuation of host cell-mediated immunity. Adenoviral vectors might thus be used to modulate Schwann cell gene expression in patients with peripheral neuropathy after appropriate immunosuppression.
Asunto(s)
Adenoviridae , Técnicas de Transferencia de Gen , Vectores Genéticos , Células de Schwann/fisiología , Nervio Ciático , beta-Galactosidasa/genética , Animales , Células Cultivadas , Técnicas de Cocultivo , Ganglios Espinales/citología , Ganglios Espinales/fisiología , Inmunidad Celular , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Ratones SCID , Reacción en Cadena de la Polimerasa , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/metabolismo , Células de Schwann/citología , Células de Schwann/inmunología , Nervio Ciático/inmunología , beta-Galactosidasa/metabolismoRESUMEN
We have developed a protocol to measure the progression of disability in patients with Charcot Marie Tooth (CMT) disease, particularly CMT1 over a several year period. Because CMT1 is a chronic disease, the natural history of changes occurring in such a brief period are not well understood, making clinical trials for CMT1 patients difficult to evaluate. We hypothesize that weakness in CMT1 correlates with axonal loss secondary to the abnormalities in Schwann cell myelin gene expression, which cause the disease. To test this hypothesis, we elected to carefully evaluate CMT patients by various modalities to measure strength, sensory loss, and axonal loss and demyelination and to compare these modalities to determine whether they correlated with findings on clinical examination. As suspected, patient weakness correlates more with secondary axonal loss than with demyelination, even though the primary abnormality in CMT1 is demyelination.
Asunto(s)
Axones/patología , Enfermedad de Charcot-Marie-Tooth/patología , Enfermedad de Charcot-Marie-Tooth/fisiopatología , Adolescente , Adulto , Anciano , Niño , Preescolar , Progresión de la Enfermedad , Humanos , Persona de Mediana Edad , Conducción NerviosaRESUMEN
IgM M-proteins in some motor neuron disease (MND) patients bind immunologically to shared determinants on gangliosides GM1 and GD1b. Since patients with these M-proteins have improved with immunotherapy the antibodies may be important in the pathogenesis of MND. To study how the M-proteins might damage motor neurons, we established co-cultures of human neurons from spinal cord explants and human myotubes. Antibodies from patient but not control serum bound to the cultured neurons. Neurons in co-cultures degenerated after incubation with patient but not control serum. These results demonstrate that anti-GM1 antibodies can bind to and destroy spinal cord neurons that are cultured with muscle. Nerve-muscle co-cultures can serve as a system to examine effects of anti-GM1/GD1b M-proteins on motor neurons.