Anthony J. Windebank

Effects of Alterations in Pulmonary Function and Sleep Variables on Survival in Patients With Amyotrophic Lateral Sclerosis

Breathing abnormalities and nocturnal hypoventilation occur in patients with amyotrophic lateral sclerosis (ALS). A prospective study was undertaken to determine the relationship of pulmonary function test abnormalities with quality of sleep and survival in 21 patients with ALS. Results of spirometry including determination of maximal respiratory pressures and arterial blood gases were compared with several formal polysomnographic variables and then also with 18-month survival. The patients had mild to moderate pulmonary function deficits, but the quality of sleep was best related to age (mean age, 58.5 years). The results of pulmonary function tests and arterial blood gas measurements did not correlate well with the presence of nocturnal breathing events or survival time, but the maximal inspiratory pressure was 86% sensitive for predicting the presence of a nocturnal oxygen saturation nadir of 80% or less and 100% sensitive for predicting 18-month survival. Although obstructive breathing events occurred, the primary explanation for the decline in nocturnal oxygen saturation was hypoventilation. We conclude that routine pulmonary function tests may be useful for screening for reductions in nocturnal oxygen saturation and also may have prognostic value. Further studies may determine whether treatment of nocturnal hypoventilation will have an effect on survival in patients with ALS who have breathing impairment.

Cisplatin-Induced Apoptosis of DRG Neurons Involves Bax Redistribution and Cytochrome cRelease But Not fas Receptor Signaling

Cisplatin causes apoptosis of DRG neurons in vitro and in vivo that can be prevented by high dose NGF. Design of a neuronal rescue strategy for patients receiving cisplatin will be facilitated by knowledge of the mechanism by which cisplatin causes DRG death. Inhibition of the fas receptor/ligand interaction prevents apoptosis in certain cancer cell lines treated with DNA damaging agents, including cisplatin. We demonstrated that killing curves from mice lacking a functional fas receptor and wild-type controls were not different over a wide range of therapeutically relevant concentrations. However, cisplatin treatment of DRG caused redistribution of cytosolic bax and mitochondrial release of cytochrome c. Bax redistribution was prevented by high dose NGF. This demonstrates for the first time that cisplatin does not signal for death via the fas pathway, but it does initiate the mitochondrial stress pathway in neurons and that NGF blocks death upstream of bax redistribution.

MSP, a trypsin-like serine protease, is abundantly expressed in the human nervous system

The goal of the present investigation was to determine the regional and cellular specific expression patterns of the newly identified serine protease, myelencephalon‐specific protease (MSP), in the adult human brain (Scarisbrick et al. [ 1997b ] J. Neurosci. 17:8156–8168). To assess the potential scope of MSP activity, Northern blot techniques were used to determine the relative abundance of MSP mRNA in 16 different adult human brain regions, and in the brain and peripheral tissues of the midgestation human fetus. The regional and temporal specific expression patterns of MSP mRNA were directly compared with those of tissue plasminogen activator (tPA), a serine protease strongly implicated in the development, ongoing plasticity, and response of the nervous system to injury and disease. mRNA encoding each protease was distributed widely throughout the normal adult human central nervous system (CNS), but the expression of each was only partially overlapping. Additionally, compared with tPA, MSP exhibited a more restricted distribution and delayed developmental onset. By immunohistochemical localization, MSP was present at moderate to high levels in neurons and oligodendroglia of the adult human brain, at a level closely resembling the relative abundance indicated by Northern blot. MSP was most abundantly expressed in the spinal cord, hippocampus, substantia nigra, and basal ganglia. The robust expression of MSP in clinically significant regions of the adult human CNS indicates that further study of this protease in terms of both normal brain physiology and neurodegenerative disorders is warranted. J. Comp. Neurol. 431:347–361, 2001.

Inflammation and neuropathic attacks in hereditary brachial plexus neuropathy

Objective: To study the role of mechanical, infectious, and inflammatory factors inducing neuropathic attacks in hereditary brachial plexus neuropathy (HBPN), an autosomal dominant disorder characterised by attacks of pain and weakness, atrophy, and sensory alterations of the shoulder girdle and upper limb muscles. Methods: Four patients from separate kindreds with HBPN were evaluated. Upper extremity nerve biopsies were obtained during attacks from a person of each kindred. In situ hybridisation for common viruses in nerve tissue and genetic testing for a hereditary tendency to pressure palsies (HNPP; tomaculous neuropathy) were undertaken. Two patients treated with intravenous methyl prednisolone had serial clinical and electrophysiological examinations. One patient was followed prospectively through pregnancy and during the development of a stereotypic attack after elective caesarean delivery. Results: Upper extremity nerve biopsies in two patients showed prominent perivascular inflammatory infiltrates with vessel wall disruption. Nerve in situ hybridisation for viruses was negative. There were no tomaculous nerve changes. In two patients intravenous methyl prednisolone ameliorated symptoms (largely pain), but with tapering of steroid dose, signs and symptoms worsened. Elective caesarean delivery did not prevent a typical postpartum attack. Conclusions: Inflammation, probably immune, appears pathogenic for some if not all attacks of HBPN. Immune modulation may be useful in preventing or reducing the neuropathic attacks, although controlled trials are needed to establish efficacy, as correction of the mutant gene is still not possible. The genes involved in immune regulation may be candidates for causing HBPN disorders.

Gene-modified mesenchymal stem cells express functionally active nerve growth factor on an engineered poly lactic glycolic acid (PLGA) substrate

Delivery of cellular and/or trophic factors to the site of injury may promote neural repair or regeneration and return of function after peripheral nerve or spinal cord injury. Engineered scaffolds provide a platform to deliver therapeutic cells and neurotrophic molecules. We have genetically engineered mesenchymal stem cells (MSCs) from the green rat (CZ-004 [SD TgN(act-EGFP)OsbCZ-004]) to express nerve growth factor (NGF) using an adenoviral vector. Cells maintained their stem cell phenotype as judged by expression of CD71 and CD172 markers, and absence of the hematopoietic marker CD45. Cells continued to express green fluorescent protein (GFP) on a long-term basis. Morphology, viability, and growth kinetics were maintained when cells were grown on a poly-lactic-co-glycolic acid (PLGA) polymer scaffold. Under appropriate growth conditions, they differentiated into chondrogenic, osteogenic, and adipogenic phenotypes, demonstrating that they retained their characteristics as MSCs. NGF was secreted from transduced MSCs at physiologically relevant levels ( approximately 25 ng/mL) measured by enzyme-linked immunoabsorbent assay (ELISA). Secreted NGF was functionally active in a neurite growth assay with PC12 cells. We conclude that MSCs are a good candidate for delivery of therapeutic factors into the injured nervous system. They are autologous, may be genetically modified to express neurotrophins, and are compatible with polymer surfaces that may be used as a potential delivery system.

Preferential expression of myelencephalon-specific protease by oligodendrocytes of the adult rat spinal cord white matter

Myelencephalon‐specific protease (MSP) is a novel serine protease that is expressed predominantly in the nervous system. In the adult rat spinal cord, MSP mRNA expression was dramatically upregulated, in both the white and gray matter, after systemic exposure to the glutamate receptor agonist, kainic acid (KA) (Scarisbrick et al. J Neurosci 17: 8156–8168, 1997b). To determine the cell‐specific expression patterns of MSP, we generated MSP‐specific monoclonal antibodies. These have been used in immunohistochemical and in situ hybridization colocalization studies, to demonstrate that MSP mRNA and protein are produced predominantly by CNP‐immunoreactive oligodendroglia, but not by GFAP‐immunoreactive astrocytes, in the white matter of the normal adult cord. In vitro, the soma of oligodendrocytes were also densely MSP immunoreactive, as were their growth tips, while astrocytes were associated with lower levels. These findings suggest that the enzymatic activity of MSP is likely to be important in the biology of oligodendrocytes and/or in the maintenance of the nerve fiber tracts of the adult spinal cord. GLIA 30:219–230, 2000.

Electrophysiologic findings and grip strength after nerve injuries in the rat forelimb

We developed electrophysiologic methods for testing the three major forelimb nerves as a tool to evaluate motor and sensory recovery in rats. Median, ulnar, or radial nerves were transected and repaired in Sprague–Dawley rats. Compound muscle action potentials (CMAPs) and somatosensory evoked potentials (SSEPs) were recorded preoperatively and at various postoperative intervals. Correlation between grip strength and CMAPs was investigated. Reliable CMAPs were recorded for all three nerves. Median‐ or ulnar‐nerve–derived SSEPs were reliably recorded; radial SSEPs could not be recorded. CMAPs followed typical regeneration patterns after nerve repair. SSEPs showed a consistent peak latency but fluctuating amplitude. Grip strength and median CMAP amplitude correlated positively. We conclude that it is possible to conduct minimally invasive electrophysiologic testing in rat forelimbs. The CMAP is a valid parameter that shows the typical time course of nerve regeneration and reinnervation. Muscle Nerve, 2008

Composite ganglioside autoantibodies and immune treatment response in MMN and MADSAM

Introduction: Multifocal motor neuropathy (MMN) is a motor only, asymmetric onset neuropathy that is relatively treatment‐refractory compared with classic chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy. Methods: We reviewed 35 patients seropositive for GM1 (monosialo‐asialo [immunoglobulin M, IgM; immunoglobulin G, IgG]) and/or GD1b (disialo [IgG, IgM]) autoantibodies having MMN, classic CIDP, or MADSAM. Immune‐treatment responsiveness and clinical course was compared with antibody negative disease controls. Results: Seventy‐nine percent of seropositives with an initial diagnosis of MMN were immunotherapy responsive compared with 46% of seronegatives (P = 0.045). Eight ganglioside antibody positive MMN patients of 19 (42%) developed sensory findings consistent with MADSAM compared with 3 of 41 (7%) seronegative MMN patients (P = 0.003). MMN and MADSAM patients with ganglioside antibody positivity had more sustained treatment responses (P = 0.03). Discussion: Patients initially diagnosed with MMN seropositive for diverse GM1 autoantibodies appear more likely to have sustained treatment response and evolution to MADSAM. Muscle Nerve 57: 1000–1005, 2018