Serum antibodies to L-type calcium channels in patients with amyotrophic lateral sclerosis

NPC1-dependent alterations in KV2.1-CaV1.2 nanodomains drive neuronal death in models of Niemann-Pick Type C disease

Lysosomes communicate through cholesterol transfer at endoplasmic reticulum (ER) contact sites. At these sites, the Niemann Pick C1 cholesterol transporter (NPC1) facilitates the removal of cholesterol from lysosomes, which is then transferred to the ER for distribution to other cell membranes. Mutations in NPC1 result in cholesterol buildup within lysosomes, leading to Niemann-Pick Type C (NPC) disease, a progressive and fatal neurodegenerative disorder. The molecular mechanisms connecting NPC1 loss to NPC-associated neuropathology remain unknown. Here we show both in vitro and in an animal model of NPC disease that the loss of NPC1 function alters the distribution and activity of voltage-gated calcium channels (CaV). Underlying alterations in calcium channel localization and function are KV2.1 channels whose interactions drive calcium channel clustering to enhance calcium entry and fuel neurotoxic elevations in mitochondrial calcium. Targeted disruption of KV2-CaV interactions rescues aberrant CaV1.2 clustering, elevated mitochondrial calcium, and neurotoxicity in vitro. Our findings provide evidence that NPC is a nanostructural ion channel clustering disease, characterized by altered distribution and activity of ion channels at membrane contacts, which contribute to neurodegeneration.

Passive Transfer of Blood Sera from ALS Patients with Identified Mutations Results in Elevated Motoneuronal Calcium Level and Loss of Motor Neurons in the Spinal Cord of Mice

Introduction: Previously, we demonstrated the degeneration of axon terminals in mice after repeated injections of blood sera from amyotrophic lateral sclerosis (ALS) patients with identified mutations. However, whether a similar treatment affects the cell body of motor neurons (MNs) remained unresolved. Methods: Sera from healthy individuals or ALS patients with a mutation in different ALS-related genes were intraperitoneally injected into ten-week-old male Balb/c mice (n = 3/serum) for two days. Afterward, the perikaryal calcium level was measured using electron microscopy. Furthermore, the optical disector method was used to evaluate the number of lumbar MNs. Results: The cytoplasmic calcium level of the lumbar MNs of the ALS-serum-treated mice, compared to untreated and healthy-serum-treated controls, was significantly elevated. While injections of the healthy serum did not reduce the number of MNs compared to the untreated control group, ALS sera induced a remarkable loss of MNs. Discussion: Similarly to the distant motor axon terminals, the injection of blood sera of ALS patients has a rapid degenerative effect on MNs. Analogously, the magnitude of the evoked changes was specific to the type of mutation; furthermore, the degeneration was most pronounced in the group treated with sera from ALS patients with a mutation in the chromosome 9 open reading frame 72 gene.

Passive Transfer of Sera from ALS Patients with Identified Mutations Evokes an Increased Synaptic Vesicle Number and Elevation of Calcium Levels in Motor Axon Terminals, Similar to Sera from Sporadic Patients

Previously, we demonstrated increased calcium levels and synaptic vesicle densities in the motor axon terminals (MATs) of sporadic amyotrophic lateral sclerosis (ALS) patients. Such alterations could be conferred to mice with an intraperitoneal injection of sera from these patients or with purified immunoglobulin G. Later, we confirmed the presence of similar alterations in the superoxide dismutase 1 G93A transgenic mouse strain model of familial ALS. These consistent observations suggested that calcium plays a central role in the pathomechanism of ALS. This may be further reinforced by completing a similar analytical study of the MATs of ALS patients with identified mutations. However, due to the low yield of muscle biopsy samples containing MATs, and the low incidence of ALS patients with the identified mutations, these examinations are not technically feasible. Alternatively, a passive transfer of sera from ALS patients with known mutations was used, and the MATs of the inoculated mice were tested for alterations in their calcium homeostasis and synaptic activity. Patients with 11 different ALS-related mutations participated in the study. Intraperitoneal injection of sera from these patients on two consecutive days resulted in elevated intracellular calcium levels and increased vesicle densities in the MATs of mice, which is comparable to the effect of the passive transfer from sporadic patients. Our results support the idea that the pathomechanism underlying the identical manifestation of the disease with or without identified mutations is based on a common final pathway, in which increasing calcium levels play a central role.

IgGs from patients with amyotrophic lateral sclerosis and diabetes target CaVα2δ1 subunits impairing islet cell function and survival

We provide evidence of a mechanistic link between ALS and T2DM. Our data show that a subgroup of ALS-T2DM patients have sera that enhance Ca_V1 channel-mediated Ca²⁺ influx and exaggerate [Ca²⁺]_i. These effects occur because the sera accommodate cytotoxic IgG autoantibodies that immunocapture Ca_Vα₂δ1 subunits. As a consequence, impairments in [Ca²⁺]_i dynamics, mitochondrial function, insulin secretion, and cell viability appear. We could clarify not only the identity of this serum factor but also the molecular mechanisms underlying its effects on the islet cells. Our findings may lay the foundation for a treatment strategy for this complex and severe group of diabetic patients.

Patients with amyotrophic lateral sclerosis (ALS) often show hallmarks of type 2 diabetes mellitus (T2DM). However, the causal link between ALS and T2DM has remained a mystery. We now demonstrate that 60% of ALS patients with T2DM (ALS-T2DM) have sera that exaggerated K⁺-induced increases in cytosolic free Ca²⁺ concentration ([Ca²⁺]_i) in mouse islet cells. The effect was attributed to the presence of pathogenic immunoglobulin Gs (IgGs) in ALS-T2DM sera. The pathogenic IgGs immunocaptured the voltage-dependent Ca²⁺ (Ca_V) channel subunit Ca_Vα₂δ1 in the plasma membrane enhancing Ca_V1 channel-mediated Ca²⁺ influx and [Ca²⁺]_i, resulting in impaired mitochondrial function. Consequently, impairments in [Ca²⁺]_i dynamics, insulin secretion, and cell viability occurred. These data reveal that patients with ALS-T2DM carry cytotoxic ALS-T2DM-IgG autoantibodies that serve as a causal link between ALS and T2DM by immunoattacking Ca_Vα₂δ1 subunits. Our findings may lay the foundation for a pharmacological treatment strategy for patients suffering from a combination of these diseases.

The C9orf72-interacting protein Smcr8 is a negative regulator of autoimmunity and lysosomal exocytosis

A mutation in C9ORF72 is the most common genetic contributor to ALS. Zhang et al. found that C9ORF72's long isoform complexes with and stabilizes SMCR8. Smcr8 loss-of-function mutant mice exhibit a loss of tolerance for many nervous system autoantigens and increased lysosomal exocytosis in mutant macrophages.

While a mutation in C9ORF72 is the most common genetic contributor to amyotrophic lateral sclerosis (ALS), much remains to be learned concerning the function of the protein normally encoded at this locus. To elaborate further on functions for C9ORF72, we used quantitative mass spectrometry-based proteomics to identify interacting proteins in motor neurons and found that its long isoform complexes with and stabilizes SMCR8, which further enables interaction with WDR41. To study the organismal and cellular functions for this tripartite complex, we generated Smcr8 loss-of-function mutant mice and found that they developed phenotypes also observed in C9orf72 loss-of-function animals, including autoimmunity. Along with a loss of tolerance for many nervous system autoantigens, we found increased lysosomal exocytosis in Smcr8 mutant macrophages. In addition to elevated surface Lamp1 (lysosome-associated membrane protein 1) expression, we also observed enhanced secretion of lysosomal components—phenotypes that we subsequently observed in C9orf72 loss-of-function macrophages. Overall, our findings demonstrate that C9ORF72 and SMCR8 have interdependent functions in suppressing autoimmunity as well as negatively regulating lysosomal exocytosis—processes of potential importance to ALS.

An electronic nose may sniff out amyotrophic lateral sclerosis

Amyothrophic lateral Sclerosis (ALS) is a neurodegenerative disease characterized by a progressive degeneration of the cortical and spinal motor neuron. Exhaled molecular profiles that have potential in the diagnosis of several respiratory and systemic diseases can be obtained by analyzing human breath with an electronic nose. We hypothesized that exhaled molecular profiling may discriminate well-characterized patients with ALS from controls. 20 ALS patients (age: 63.5±12.3), and 20 healthy controls (age: 58.1±4.4) participated in a cross-sectional study. A Tedlar bag was used to collect exhaled breath by using a validated method. Bags were then sampled by an electronic nose (Cyranose 320). Statistical analysis on sensor responses was performed off-line by principal component analysis, linear discriminant analysis and ROC curves. Breathprints from patients with ALS were discriminated from healthy controls (CVA: 75.0%; p=0.003; AUC 0.795). Based on our results, patients with ALS can be discriminated from healthy controls. This suggests that exhaled breath analysis has potential for screening and/or diagnosis of this neuromuscular disease.

Calcium in the pathomechanism of amyotrophic lateral sclerosis - Taking center stage?

Amyotrophic lateral sclerosis is an incurable, relentlessly progressive disease primarily affecting motor neurons. The cause of the disease, except for the mutations identified in a small fraction of patients, is unknown. The major mechanisms contributing to the degeneration of motor neurons have already been disclosed and characterized, including excitotoxicity, oxidative stress, mitochondrial dysfunction, and immune/inflammatory processes. During the progression of the disease these toxic processes are not discrete, but each facilitates the deleterious effect of the other. However, due to their common reciprocal calcium dependence, calcium ions may act as a common denominator and through a positive feedback loop may combine the individual pathological processes into a unified escalating mechanism of neuronal destruction. This mini-review provides an overview of the mutual calcium dependence of the major toxic mechanisms associated with amyotrophic lateral sclerosis.

Pathogenic Mechanisms in Sporadic Amyotrophic Lateral Sclerosis

In recognition of the 100th anniversary of Charcot’s death we have reviewed possible pathogenic mechanisms in amyotrophic lateral sclerosis (ALS). Advances in the last 5 years in molecular biology and genetics have identified mutations in the cytosolic dismutase (SODI) gene in some patients with familial ALS raising the possibility that oxidative stress may be involved in the pathogenesis. An excitotoxic pathogenesis has been implicated based on elevated plasma and CSF levels of amino acids and altered contents of amino acids in the nervous system of ALS patients and changes in the number of excitatory amino acid receptors. ALS sera containing antibodies to L-type calcium channels and the development of immune mediated lower and upper and lower motor neuron models have revitalized research efforts focusing on an immune basis for ALS. Other pathogenic mechanisms which have been the subject of recent research include elemental toxicity, apoptosis and programmed cell death and possibly a deficiency or abnormality in growth factors. Pathogenic processes for ALS must account for an increasing incidence of ALS, male preponderance, and the selective vulnerability of the corticomotoneuronal system.

Effect of ALS IgG on Motor Neurons in Organotypic Spinal Cord Cultures

Objective:

Reports about the role of autoimmunity in amyotrophic lateral sclerosis (ALS) are inconsistent. The aim of this work was to investigate the effect of IgG from patients with ALS on motor neurons in a physiological-like surrounding.

Methods:

Using affinity chromatography, IgG from six ALS patients, four disease controls and five healthy subjects was purified. Organotypic spinal cord cultures, which conserve the structure of the spinal cord in a horizontal plane and are suitable for studies with long-term treatment, were used and IgG with different concentrations ranging from 0.05 mg/mL to 0.5 mg/mL was added to the culture medium. Ventral motor neuron survival was evaluated by morphology and SMI-32 immunohistochemistry staining. Lactate dehydrogenase (LDH) level in the culture medium was measured by colorimetry.

Results:

After cultures were treated with ALS IgG for three weeks, the number and morphology of motor neurons showed little change. In addition, there was no significant difference in lactate dehydrogenase release between cultures treated with medium alone, normal control IgG, disease control IgG or ALS IgG.

Conclusions:

The results indicate that IgG from these ALS patients was insufficient per se to induce motor neuron death in Organotypic slice cultures. However, this does not preclude the possibility that other changes may have occurred in the motor neurons. This work offered a new model to evaluate the role of IgG in the pathogenesis of ALS. Organotypic cultures contribute to study of the impact of IgG on motor neurons by mimicking physiological conditions.

Highly immunoreactive IgG antibodies directed against a set of twenty human proteins in the sera of patients with amyotrophic lateral sclerosis identified by protein array

Amyotrophic lateral sclerosis (ALS), the most common adult-onset motor neuron disorder, is characterized by the progressive and selective loss of upper and lower motor neurons. Diagnosis of this disorder is based on clinical assessment, and the average survival time is less than 3 years. Injections of IgG from ALS patients into mice are known to specifically mark motor neurons. Moreover, IgG has been found in upper and lower motor neurons in ALS patients. These results led us to perform a case-control study using human protein microarrays to identify the antibody profiles of serum samples from 20 ALS patients and 20 healthy controls. We demonstrated high levels of 20 IgG antibodies that distinguished the patients from the controls. These findings suggest that a panel of antibodies may serve as a potential diagnostic biomarker for ALS.

Pathogenic immune mechanisms at the neuromuscular synapse: the role of specific antibody-binding epitopes in myasthenia gravis

Autoantibodies against three different postsynaptic antigens and one presynaptic antigen at the neuromuscular junction are known to cause myasthenic syndromes. The mechanisms by which these antibodies cause muscle weakness vary from antigenic modulation and complement-mediated membrane damage to inhibition of endogenous ligand binding and blocking of essential protein-protein interactions. These mechanisms are related to the autoantibody titre, specific epitopes on the target proteins and IgG autoantibody subclass. We here review the role of specific autoantibody-binding epitopes in myasthenia gravis, their possible relevance to the pathophysiology of the disease and potential implications of epitope mapping knowledge for new therapeutic strategies.

Amyotrophic lateral sclerosis with positive anti-acetylcholine receptor antibodies. Case report and review of the literature

Myasthenia gravis is a nerve-muscle junction disease, for which the most specific test is an increase in the anti-acetylcholine receptor antibodies (anti-AChR-Abs) titer. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting both upper and lower motor neurons. Positive AChR-Ab in patients with pure ALS are exceedingly rare. We report the case of a patient with confirmed ALS and very high levels of AChR-Ab and review the literature on this topic.

Increased risk of pneumocystis jiroveci pneumonia among patients with inflammatory bowel disease

OBJECTIVES

Patients with inflammatory bowel disease (IBD) may be at increased risk for pneumocystis jiroveci pneumonia (PCP). Our aims were (1) to determine the incidence and relative risk of PCP in IBD and (2) to describe medication exposures in patients with IBD with PCP.

METHODS

We performed a retrospective cohort study and a case series using administrative data from IMS Health Inc, LifeLink Health Plan Claims Database. In the cohort, patients with IBD were matched to 4 individuals with no IBD claims. PCP risk was evaluated by incidence rate ratio and adjusted Cox proportional hazards modeling. The demographics and medication histories of the 38 cases of PCP in patients with IBD were extracted.

RESULTS

The cohort included 50,932 patients with Crohn's disease, 56,403 patients with ulcerative colitis, and 1269 patients with unspecified IBD; matched to 434,416 individuals without IBD. The crude incidence of PCP was higher in the IBD cohort (10.6/100,000) than in the non-IBD cohort (3.0/100,000). In the adjusted analyses, PCP risk was higher in the IBD versus non-IBD cohort (hazard ratio, 2.96; 95% confidence interval, 1.75-4.29), with the greatest risk in Crohn's disease compared with non-IBD (hazard ratio, 4.01; 95% confidence interval, 1.88-8.56). In the IBD case series of PCP cases (n = 38), the median age was 49 (interquartile range, 43-57). A total of 20 individuals (53%) were on corticosteroids alone or in combination with other immunosuppression.

CONCLUSIONS

Although the overall incidence of PCP is low, patients with IBD are at increased risk. Patients with IBD with PCP are predominantly on corticosteroids alone or in combination before PCP diagnosis.

Calcium channel agonists protect against neuromuscular dysfunction in a genetic model of TDP-43 mutation in ALS

TAR DNA binding protein (TDP-43, encoded by the TARDBP gene) has recently been shown to be associated with amyotrophic lateral sclerosis (ALS), but the early pathophysiological deficits causing impairment in motor function are unknown. Here we expressed the wild-type human gene (wtTARDBP) or the ALS mutation G348C (mutTARDBP) in zebrafish larvae and characterized their motor (swimming) activity and the structure and function of their neuromuscular junctions (NMJs). Of these groups only mutTARDBP larvae showed impaired swimming and increased motoneuron vulnerability with reduced synaptic fidelity, reduced quantal transmission, and more orphaned presynaptic and postsynaptic structures at the NMJ. Remarkably, all behavioral and cellular features were stabilized by chronic treatment with either of the L-type calcium channel agonists FPL 64176 or Bay K 8644. These results indicate that expression of mutTARDBP results in defective NMJs and that calcium channel agonists could be novel therapeutics for ALS.

Amyotrophic lateral sclerosis immunoglobulins G enhance the mobility of Lysotracker-labelled vesicles in cultured rat astrocytes

AIM

We examined the effect of purified immunoglobulins G (IgG) from patients with amyotrophic lateral sclerosis (ALS) on the mobility and exocytotic release from Lysotracker-stained vesicles in cultured rat astrocytes.

METHODS

Time-lapse confocal images were acquired, and vesicle mobility was analysed before and after the application of ALS IgG. The vesicle counts were obtained to assess cargo exocytosis from stained organelles.

RESULTS

At rest, when mobility was monitored for 2 min in bath with Ca(2+), two vesicle populations were discovered: (1) non-mobile vesicles (6.1%) with total track length (TL) < 1 μm, averaging at 0.33 ± 0.01 μm (n = 1305) and (2) mobile vesicles (93.9%) with TL > 1 μm, averaging at 3.03 ± 0.01 μm (n = 20,200). ALS IgG (0.1 mg mL(-1)) from 12 of 13 patients increased the TL of mobile vesicles by approx. 24% and maximal displacement (MD) by approx. 26% within 4 min, while the IgG from control group did not alter the vesicle mobility. The mobility enhancement by ALS IgG was reduced in extracellular solution devoid of Ca(2+), indicating that ALS IgG vesicle mobility enhancement involves changes in Ca(2+) homeostasis. To examine whether enhanced mobility relates to elevated Ca(2+) activity, cells were stimulated by 1 mm ATP, a cytosolic Ca(2+) increasing agent, in the presence (2 mm) and in the absence of extracellular Ca(2+). ATP stimulation triggered an increase in TL by approx. 7% and 12% and a decrease in MD by approx. 11% and 1%, within 4 min respectively. Interestingly, none of the stimuli triggered the release of vesicle cargo.

CONCLUSION

Amyotrophic lateral sclerosis-IgG-enhanced vesicle mobility in astrocytes engages changes in calcium homeostasis.

Amyotrophic lateral sclerosis-immunoglobulins selectively interact with neuromuscular junctions expressing P/Q-type calcium channels

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by a gradual loss of motoneurons. The majority of ALS cases are associated with a sporadic form whose etiology is unknown. Several pieces of evidence favor autoimmunity as a potential contributor to sporadic ALS pathology. To gain understanding concerning possible antigens interacting with IgGs from sporadic ALS patients (ALS-IgGs), we studied immunoreactivity against neuromuscular junction (NMJ), spinal cord and cerebellum of mice with and without the Ca(V) 2.1 pore-forming subunit of the P/Q-type voltage-gated calcium (Ca(2+)) channel. ALS-IgGs showed a strong reactivity against NMJs of wild-type diaphragms. ALS-IgGs also increased muscle miniature end-plate potential frequency, suggesting a functional role for ALS-IgGs on synaptic signaling. In support, in mice lacking the Ca(V) 2.1 subunit ALS-IgGs showed significantly reduced NMJ immunoreactivity and did not alter spontaneous acetylcholine release. This difference in reactivity was absent when comparing N-type Ca(2+) channel wild-type or null mice. These results are particularly relevant because motoneurons are known to be early pathogenic targets in ALS. Our findings add further evidence supporting autoimmunity as one of the possible mechanisms contributing to ALS pathology. They also suggest that serum autoantibodies in a subset of ALS patients would interact with NMJ proteins down-regulated when P/Q-type channels are absent.

Autoimmunity in amyotrophic lateral sclerosis: past and present

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting particularly motor neurons for which no cure or effective treatment is available. Although the cause of ALS remains unknown, accumulative evidence suggests an autoimmune mechanism of pathogenesis. In this paper, we will summarize the current research related to autoimmunity in the sporadic form of ALS and discuss the potential underlying pathogenic mechanisms and perspectives. Presented data supports the view that humoral immune responses against motor nerve terminals can initiate a series of physiological changes leading to alteration of calcium homeostasis. In turn, loss of calcium homeostasis may induce neuronal death through apoptotic signaling pathways. Additional approaches identifying specific molecular features of this hypothesis are required, which will hopefully allow us to develop techniques of early diagnosis and effective therapies.

Intrinsic properties of lumbar motor neurones in the adult G127insTGGG superoxide dismutase-1 mutant mouse in vivo: evidence for increased persistent inward currents

AIM

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by a preferential loss of motor neurones. Previous publications using in vitro neonatal preparations suggest an increased excitability of motor neurones in various superoxide dismutase-1 (SOD1) mutant mice models of ALS which may contribute to excitotoxicity of the motor neurones.

METHODS

Using intracellular recording, we tested this hypothesis in vivo in the adult presymptomatic G127insTGGG (G127X) SOD1 mutant mouse model of ALS.

RESULTS

At resting membrane potentials the basic intrinsic properties of lumbar motor neurones in the adult presymptomatic G127X mutant are not significantly different from those of wild type. However, at more depolarized membrane potentials, motor neurones in the G127X SOD1 mutants can sustain higher frequency firing, showing less spike frequency adaption (SFA) and with persistent inward currents (PICs) being activated at lower firing frequencies and being more pronounced.

CONCLUSION

We demonstrated that, in vivo, at resting membrane potential, spinal motor neurones of the adult G127X mice do not show an increased excitability. However, when depolarized they show evidence of an increased PIC and less SFA which may contribute to excitotoxicity of these neurones as the disease progresses.

Congenital heart block: identification of autoantibody binding site on the extracellular loop (domain I, S5-S6) of alpha(1D) L-type Ca channel

Congenital heart block (CHB) is an autoimmune disease associated with autoantibodies against intracellular ribonucleoproteins SSB/La and SSA/Ro. The hallmark of CHB is complete atrioventricular block. We have recently established that anti-SSA/Ro -SSB/La autoantibodies inhibit alpha(1D) L-type Ca current, I(Ca-L), and cross-react with the alpha(1D) Ca channel protein. This study aims at identifying the possible binding sites on alpha(1D) protein for autoantibodies from sera of mothers with CHB children. GST fusion proteins of the extracellular regions between the transmembrane segments (S5-S6) of each of the four alpha(1D) Ca channel protein domains I-IV were prepared and tested for reactivity with sera from mothers with CHB children and controls using ELISA. Sera containing anti-Ro/La autoantibodies from 118 mothers with CHB children and from 15 mothers with anti-Ro/La autoantibodies but have healthy children, and from 28 healthy mothers without anti-Ro/La autoantibodies and healthy children were evaluated. Seventeen of 118 (14.4%) sera from mothers with CHB children reacted with the extracellular loop of domain I S5-S6 region (E1). In contrast, only 2 of 28 (7%) of sera from healthy mothers (-anti-Ro/La) and healthy children reacted with E1 loop and none (0 of 15) of sera from healthy mothers (+anti-Ro/La) and healthy children reacted with the E1 loop. Preincubation of E1 loop with the positive sera decreased the O.D reading establishing the specificity of the response. Electrophysiological characterization of the ELISA positive sera and purified IgG showed inhibition (44.1% and 49.8%, respectively) of the alpha(1D) I(Ca-L) expressed in tsA201 cells. The inhibition was abolished when the sera were pre-incubated with E1 fusion protein. The results identified the extracellular loop of domain I S5-S6 of L-type Ca channel alpha(1D) subunit as a target for autoantibodies from a subset of mothers with CHB children. This novel finding provides insights into the potential development of therapeutic peptides that could bind to the pathogenic antibodies and prevent CHB.

Alternation of neurofilaments in immune-mediated injury of spinal cord motor neurons

STUDY DESIGN

Observational cross-section study.

OBJECTIVE

The objective of our study was to determine if phosphorylation of aggregated neurofilaments (NFs) would occur in autoimmune-mediated motor neuron injury. Our main hypothesis was that autoimmune-mediated damage of spinal cord motor neurons may influence NF phosphorylation and lead to NF aggregation.

METHODS

A total of 20 guinea pigs were inoculated with bovine spinal cord anterior horn homogenates (experimental autoimmune gray matter model) and 20 guinea pigs were inoculated with phosphate-buffered saline (control). NF phosphorylation and aggregation were observed by immunohistochemistry and electron microscopic examination. Data were analyzed using Student's t-test with P<0.05 being considered significant.

RESULTS

Abnormal phosphorylation and distribution of NF occurred in motor neurons and axons of animals with experimental autoimmune gray matter disease but not in the control animals.

CONCLUSION

Aberrant accumulation and phosphorylation of neurofilaments in perikarya of spinal cord motor neurons occur in immune-mediated motor neuron death. As both immunologic response and alteration of neurofilaments are observed in amyotrophic lateral sclerosis (ALS) patients and aberrant neurofilament change harms motor neurons, our present findings suggest that autoimmunity-induced ALS may mediate in part through neurofilament modification.

Models of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurological disorder caused by degeneration of the motor neurons in cortex, brainstem and spinal cord. Two experimental models of ALS are described in this unit: organotypic cultures of spinal cord, and transgenic mice expressing a human mutant superoxide dismutase 1 (SOD1) gene. Appropriate animal and cell culture models of ALS can be used to help unravel the sequence of events in motor neuronal degeneration and test potential therapies.

Golgi apparatus and neurodegenerative diseases

Neurodegenerative disorders are typically characterized by progressive and extensive neuronal loss in specific populations of neurons and brain areas which lead to the observed clinical manifestations. Despite the recent advances in molecular neuroscience, the subcellular bases such as Golgi apparatus (GA) for most neurodegenerative diseases are poorly understood. This review gives a brief overview of the contribution of the neuronal GA in the pathogeneses of neurodegeneration, summarizes what is known of the GA machinery in these diseases, and present the relationship between GA fragmentation and the aggregation and accumulation of misfolded or aberrant proteins including mutant SOD1, a-synuclein, tau, which is considered to be a key event in the pathogenic process, and perturbating in calcium homeostasis, regulation of hormones, lipid metabolism are also linkage to the function of the GA thought to underlie neurodegeneration. Although these precise diseases mechanisms remain to be clarified, more research is needed to better understand how GA function for it and to enable physicians to use this knowledge for the benefit of the patients.

Prophylaxis against Pneumocystis pneumonia in patients with inflammatory bowel disease: toward a standard of care

Patients with Crohn's Disease and ulcerative colitis are increasingly treated with a host of immunomodulatory and immunosuppressive medications, including thiopurines and antibody-based biologic agents. Despite the known infectious complications associated with these therapies from the HIV and solid organ transplant literature, there are currently no well-defined concise guidelines to assist gastroenterologists and other physicians in the utility and indication for prophylaxis against Pneumocystis pneumonia and other infections in inflammatory bowel disease (IBD) patients. In this article, we discuss the evidence of various infections associated with immunocompromise in HIV/AIDS, organ transplantation, and in other immunocompromised states, and discuss the evidence for the efficacy and safety of various infectious prophylaxis protocols. In addition, we discuss the evidence for Pneumocystis and other infections in IBD patients treated with corticosteroids, azathioprine/6-MP, biologic agents and other therapies, and we present the case for various antibiotic (and antiviral) regimens to prevent such infections. Based on the review of the literature, this discussion represents a true call for guidelines for infection prophylaxis, to help guide gastroenterologists and all practitioners who care for the challenging population of IBD patients.

Efficacy and safety of tacrolimus in refractory ulcerative colitis and Crohn's disease: a single-center experience

BACKGROUND

The published experience regarding the use of tacrolimus in Crohn's disease (CD) and ulcerative colitis (UC) refractory to more commonly used medical therapy has been fairly limited. Our objective was to describe our experience with its use in a cohort of patients which, to our knowledge, represents the largest North American cohort described to date.

METHODS

This was a retrospective, single-center chart analysis. Patients were identified by compiling all hospital discharges with principle diagnoses of ICD-9 codes for 555.0-555.9 (regional enteritis) and 556.0-556.9 (ulcerative colitis) from January 1, 2000, to October 31, 2005, and then cross-referencing the electronic charts for tacrolimus serum concentrations ordered during this time period. Additional patients were identified through verbal communication with participating clinicians. Information abstracted included proportion with clinical response and remission (using a modified disease activity index), ability to wean from steroids, need for surgery / time to surgery, and side-effect profile.

RESULTS

In all, 32 UC patients and 15 CD patients were identified. The mean disease duration was: UC 81 months (range, 1 month to 37 years), CD 100 months (range, 1 month to 35 years). The disease distribution for UC was: pancolitis 12 (37.5%), extensive colitis 6 (18.8%), left-sided 11 (34.4%), and proctitis 3(9.4%). For CD this was: TI 2 (13.3%), small bowel 2 (13.3%), colonic 3 (20.7%), ileocolonic 7(46.7%), and perianal 1 (6.7%). The duration of tacrolimus treatment for UC was mean, 29 weeks. For CD it was mean, 9.9 weeks. In all, 30/32 UC and 7/15 CD patients were on steroids; 4/30 UC and 0/7 CD patients were able to subsequently wean off steroids. In all, 12/32 UC patients proceeded to colectomy. Mean time to colectomy was 28 weeks and 6/15 CD patients proceeded to a resective surgery. The mean time to surgery was 22 weeks. In all, 22/32 UC patients achieved a clinical response; 3/32 achieved remission and 8/15 CD patients achieved a clinical response; 1/15 achieved remission. Adverse reactions were generally mild. In 6 patients the drug had to be discontinued because of an adverse reaction. There were no opportunistic infections identified, no cases of renal insufficiency related to drug administration, and no deaths while on the medicine.

CONCLUSIONS

Our experience with tacrolimus in UC and CD indicates that it is safe and relatively well tolerated, although its clinical efficacy is quite variable. More prospective studies assessing its use are necessary.

The use of tacrolimus in the treatment of inflammatory bowel disease

Tacrolimus is a calcineurin inhibitor that suppresses pro-inflammatory cytokine production and T-cell activation. These immunosuppressant effects have been used to treat inflammatory bowel disease, especially fistulising Crohn's disease and refractory ulcerative colitis. The more predictable oral bioavailability and better side-effect profile makes tacrolimus a more favourable choice as compared with ciclosporin. Dose-dependent side effects, such as nephrotoxicity, are reported but are mostly reversible with dose reduction or cessation of therapy. Topical tacrolimus has also been used to treat pyoderma gangrenosum, an extra-intestinal manifestation of inflammatory bowel disease. Tacrolimus is well-tolerated and should be considered as an alternative agent in the treatment of inflammatory bowel disease, especially those intolerant or refractory to the more conventional immunomodulators.

Parkinson disease IgG and C5a-induced synergistic dopaminergic neurotoxicity: Role of microglia

Increasing evidence suggests the involvement of immune/inflammatory system in Parkinson's disease (PD). Many immune/inflammatory factors may synergistically participate in PD. In this study, we demonstrated that immunoglobulin G from the serum of 4/11 PD patients (PDIgG, 60microg/ml) and recombinant human C5a (0.1nM) synergistically induced selective dopaminergic neurodegeneration in rat mesencephalic neuron-glia cultures, while that PDIgG alone or C5a alone was minimally toxic or nontoxic. IgG from 17 disease controls and from 7 normal controls did not significantly induce dopaminergic neurotoxicity in the cultures even in the presence of C5a. Using mesencephalic neuron-enriched cultures, we found that the synergistic dopaminergic neurotoxicity was mediated by glia. The results from microglia-supplemented neuronal cultures, astroglia-supplemented neuronal cultures and neuron-astroglia cocultures indicated that microglia, not astroglia, played a pivotal role in the neurotoxicity. Through immunocytochemistry analysis and assay of proinflammatory factors, we observed that each of the four PDIgGs (60microg/ml) and C5a (0.1nM) synergistically induced microglia activation and production of superoxide and nitric oxide (NO) in neuron-glia cultures. Further investigations indicated that superoxide and NO were both responsible for the synergistic neurotoxicity. Finally, using F(ab')(2) fragments of PDIgG, we demonstrated that microglial Fc receptors may play an important role in the neurotoxicity. Our work provides new evidence for the involvement of the immune/inflammatory system in PD and helpful clues for studying the combined effect of antibody and complement on microglia.

Serine proteases purified from sera of patients with amyotrophic lateral sclerosis (ALS) induce contrasting cytopathology in murine motoneurones to IgG

Affinity purified IgG from sera of patients with amyotrophic lateral sclerosis (ALS) is claimed to enhance transmitter release, induce apoptotic death of cultured motoneurones, and elicit a distinctive cytopathology with raised Ca(2+) in mouse motoneurones. An alternative hypothesis attributes these events to serine proteases in ALS sera. To test this, motoneurones in BALB/c mice injected intraperitoneally with plasminogen affinity purified from sera of ALS patients and healthy controls were analysed using immunochemical and ultrastructural morphometric methods. The responses were validated in motoneurones of mice injected with commercially purified plasminogen, tissue plasminogen activator (tPA), or plasmin. Motoneurones in non-injected mice had normal morphology and ultrastructure without evidence of electron-dense degeneration. Purified plasminogen from both ALS patients and healthy controls, evoked electron-dense motoneurone degeneration, as did commercially purified plasminogen and tPA. The common cytopathology comprised disruption and distension of Nissl body rough endoplasmic reticulum, cytoplasmic polyribosomal proliferation, and significant Ca(2+) enhancement in mitochondria. By contrast, using affinity purified serum immunoglobulins, ALS-IgG but not IgG from healthy or disease controls, elicited necrosis, with 30% of ALS-IgGs tested evoking electron-dense degeneration in 40% of motoneurones. The primary cytopathology was extensive swelling of Golgi endoplasmic reticulum and mitochondria, with enhancement of Ca(2+) in Golgi endoplasmic reticulum and presynaptic boutons. We conclude that serine proteases purified from sera of ALS patients elicits a distinctive cytopathology and pattern of Ca(2+) enhancement in motoneurones different from that found on passive transfer of affinity purified ALS-IgG.

Calcium signaling pathways mediating synaptic potentiation triggered by amyotrophic lateral sclerosis IgG in motor nerve terminals

Sporadic amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects particularly motoneurons. Several pieces of evidence suggested the involvement of autoimmune mechanisms mediated by antibodies in ALS. However, the significance of those antibodies in the disease and the underlying mechanisms are unknown. Here we showed that IgG purified from a group of sporadic ALS patients, but not familial ALS patients, specifically interact with the presynaptic membrane of motoneurons through an antigen-antibody interaction and modulated synaptic transmission. Immunoreactivity against nerve terminals showed strong correlation with synaptic modulation ability. In addition, several controls have ruled out the possibility for this synaptic modulation to be mediated through proteases or nonspecific effects. Effective IgG potentiated both spontaneous and asynchronous transmitter release. Application of pharmacological inhibitors suggested that activation of this increased release required a nonconstitutive Ca2+ influx through N-type (Cav2.2) channels and phospholipase C activity and that activation of IP3 and ryanodine receptors were necessary to both activate and sustain the increased release. Consistent with the notion that ALS is heterogeneous disorder, our results reveal that, in approximately 50% of ALS patients, motor nerve terminals constitutes a target for autoimmune response.

[Antireceptor and antichannel autoantibodies]

This review of literature concerns the different autoantibodies directed against membrane receptors and ion channels. The target antigens, the associated pathologies, the pathogenesis and the methods of detection of these autoantibodies will be addressed. Some of these autoantibodies are thought to be closely related to the autoimmune disease whereas for some others their pathogenesis role is still unclear. Overall, the roles of antibodies are different between diseases, but the presence of such autoantibodies support the basis of intervening immunotherapy, antibody titers predicted the activity of the diseases and some of them are very specific and become the useful markers for the diagnosis. Some autoantibodies are detected routinely as the antiacetylcholine receptor, voltage-gated potassium and calcium channels autoantibodies whereas most of them are detected very rarely and only by specialized laboratories. This review will be divided in three parts with the following classification: the first group of autoantibodies directed against membrane receptors included receptors with an enzymatic activity (mostly tyrosine kinase) with one transmembrane domain, receptors associated to G protein with seven transmembrane domains, ion channels and receptors associated to the membrane by the glycosyl phosphatidyl inositol and the second group of intracellular receptor autoantibodies directed to the estrogens, androgens, lamin and kinesin receptors.

Potential clinical applications using stem cells derived from human umbilical cord blood

There is an abundance of clinical applications using human umbilical cord blood (HUCB) as a source for stem cell populations. Other than haematopoietic progenitors, there are mesenchymal, endothelial stem cells and neuronal precursors, in varying quantities, that are found in human umbilical cord blood. These may be useful in diseases such as immune deficiency and autoimmune disorders. Considering issues of safety, availability, transplant methodology, rejection and side effects, it is contended that a therapeutic stem cell transplant, utilizing stem cells from HUCB, provides a reliable repository of early precursor cells that can be useful in a great number of diverse conditions. Drawbacks of relatively smaller quantities of mononucleated cells in one unit of cord blood can be mitigated by in-vitro expansion procedures, improved in-vivo signalling, and augmentation of the cellular milieu, while simultaneously choosing the appropriate transplantation site and technique for introduction of the stem cell graft.

Intravenous cyclosporine for the treatment of severe steroid refractory ulcerative colitis: what is the cost?

PURPOSE

Intravenous cyclosporine often is used to treat patients with severe steroid refractory colitis secondary to ulcerative colitis in an attempt to avoid urgent total abdominal colectomy. The purpose of this study was to evaluate the success and cost of cyclosporine.

METHODS

A retrospective, chart review of all patients from 1996 to 2002 who were treated with cyclosporine and/or had a three-stage ileal pouch-anal anastomosis for severe steroid refractory colitis at our institution was performed. Patients were divided into three groups: TAC and CyA: patients who failed cyclosporine and had urgent total abdominal colectomy on the same admission; TAC no CyA: patients who had an urgent total abdominal colectomy without cyclosporine; and CyA only: patients treated successfully with cyclosporine and discharged without surgery. A subgroup of patients who had an ileal pouch-anal anastomosis was identified from each group. Cost data were obtained from the hospital's financial records.

RESULTS

Forty-one patients (25 males) were identified. Twenty-nine patients received cyclosporine for severe steroid refractory colitis. Of these, 18 (62 percent) failed and underwent total abdominal colectomy on the same admission. Eleven (38 percent) responded to the cyclosporine and were discharged. Of the 11, 4 never had surgery, 1 had a three-stage ileal pouch-anal anastomosis, 5 had a two-stage ileal pouch-anal anastomosis, and 1 had a total abdominal colectomy only. Only 14 percent of patients avoided colectomy in the long-term. Complications of cyclosporine occurred in 8 patients (28 percent), and surgical complications occurred in 12 patients.

CONCLUSIONS

The highest costs, highest length of stay, and highest number of overall complications were found in the group of patients who failed intravenous cyclosporine and required colectomy during the same hospitalization.

ALS-IgG-induced selective motor neurone apoptosis in rat mixed primary spinal cord cultures

There is evidence that in sporadic amyotrophic lateral sclerosis (ALS) immunological mechanisms may be involved in the pathophysiology of the disease. We tested whether purified IgG from ALS patients induce cell death in rat mixed primary spinal cord cultures and compared this with the effect of IgG purified from patients with Guillain-Barré syndrome (GBS) or from healthy donors. Treatment with ALS-IgG increases caspase-3 apoptosis when compared with control IgG or with GBS-IgG, but does not induce death by necrosis. Because ALS is characterized by the selective loss of motor neurones, we next assessed the differential effect of ALS-IgG on motor neurones or astrocytes. We showed, semiquantitatively, that motor neurones are more susceptible to apoptosis when cultures were treated with ALS-IgG compared with control-IgG. In conclusion, we have demonstrated in primary spinal cord cultures that IgG from patients with ALS induces apoptosis selectively in motor neurones, and that the caspase-3 pathway is involved. This suggests that immunological mechanisms may contribute to the selective loss of motor neurones in ALS.

Novel molecular mechanism involving alpha1D (Cav1.3) L-type calcium channel in autoimmune-associated sinus bradycardia

BACKGROUND

Congenital heart block (CHB) is an autoimmune disease that affects fetuses/infants born to mothers with anti-Ro/La antibodies (positive IgG). Although the hallmark of CHB is complete atrioventricular block, sinus bradycardia has been reported recently in animal models of CHB. Interestingly, knockout of the neuroendocrine alpha1D Ca channel in mice results in significant sinus bradycardia and atrioventricular block, a phenotype reminiscent to that seen in CHB. Here, we tested the hypothesis that the alpha1D Ca channel is a novel target for positive IgG.

METHODS AND RESULTS

Reverse transcription-polymerase chain reaction, confocal indirect immunostaining, and Western blot data established the expression of the alpha1D Ca channel in the human fetal heart. The effect of positive IgG on alpha1D Ca current (I(Ca-L)) was characterized in heterologous expression systems (tsA201 cells and Xenopus oocytes) because of the unavailability of alpha1D-specific modulators. alpha1D I(Ca-L) activated at negative potentials (between -60 and -50 mV). Positive IgG inhibited alpha1D I(Ca-L) in both expression systems. This inhibition was rescued by a Ca channel activator, Bay K8644. No effect on alpha1D I(Ca-L) was observed with negative IgG and denatured positive IgG. Western blot data showed that positive IgG binds directly to alpha1D Ca channel protein.

CONCLUSIONS

The data are the first to demonstrate (1) expression of the alpha1D Ca channel in human fetal heart, (2) inhibition of alpha1D I(Ca-L) by positive IgG, and (3) direct cross-reactivity of positive IgG with the alpha1D Ca channel protein. Given that alpha1D I(Ca-L) activates at voltages within the pacemaker's diastolic depolarization, inhibition of alpha1D I(Ca-L) in part may account for autoimmune-associated sinus bradycardia. In addition, Bay K8644 rescue of alpha1D I(Ca-L) inhibition opens new directions in the development of pharmacotherapeutic approaches in the management of CHB.

Therapeutic developments in amyotrophic lateral sclerosis

There is currently no effective treatment for amyotrophic lateral sclerosis (ALS), a devastating disorder of the human nervous system that, due to motoneurone degeneration, causes progressive loss of muscle function and death. The relentless progression of ALS and the uniformly poor prognosis have been unhindered by a variety of therapeutic agents tested in previous clinical studies. Recently, two drugs, namely riluzole and recombinant human insulin-like growth factor-I (IGF-1), have been reported to benefit patients with ALS by improving survival or slowing disease progression. Several other drugs, such as gabapentin and various neurotrophic factors, are being investigated in on-going clinical trials. Therapeutic developments in ALS have been hampered by the fact that the precise cause of the disease remains unknown. In addition, there are considerable variations in disease related characteristics among patients, rendering accurate measurements of disease progression difficult. Advances in theories of pathogenesis, such as genetic factors, glutamate excitotoxicity, oxidative stress, autoimmune mechanism and cytoskeletal abnormality will help guide the development of future therapies. Newer approaches to therapy may include suitable glutamate antagonists, small molecules that augment neurotrophic factor function, and anti-oxidants. Combination therapy of effective agents should be considered.

Differential expression of voltage-activated calcium channels in III and XII motoneurones during development in the rat

To further our understanding of the role that voltage-activated Ca2+ channels play in the development, physiology and pathophysiology of motoneurones (MNs), we used whole-cell patch-clamp recording to compare voltage-activated Ca2+ currents in oculomotor (III) and hypoglossal (XII) MNs of neonatal [postnatal day (P)1-5] and juvenile (P14-19) rats. In contrast to III MNs that innervate extraocular muscles, XII MNs that innervate tongue muscles mature more rapidly, fire bursts of low frequency action potentials and are vulnerable to degeneration in amyotrophic lateral sclerosis. In neonates, low voltage-activated (LVA) Ca2+ current densities are similar in XII and III MNs but high voltage-activated (HVA) Ca2+ current densities are twofold higher in XII MNs. The HVA Ca2+ channel antagonists (nimodipine and nifedipine for L-type, omega-agatoxin-TK for P/Q-type and omega-conotoxin-GVIA for N-type) revealed that, while N- and P/Q-type HVA Ca2+ channels are present in both MN pools, a 3.5-fold greater P/Q-type Ca2+ current in XII MNs accounts for their greater HVA Ca2+ currents. Developmentally, LVA and HVA Ca2+ current densities decrease in III MNs but remain unchanged in XII MNs. Thus, the differences between these MN pools increase developmentally so that, in juveniles, the LVA Ca2+ current density is twofold greater and the HVA Ca2+ current density is threefold greater in XII compared with III MNs. We propose that this differential expression of LVA and HVA Ca2+ channels in XII and III MNs during development contributes to their distinct physiology and may also be a factor contributing to the greater susceptibility of XII MNs to degeneration as seen in amyotrophic lateral sclerosis.

Pneumocystis carinii pneumonia during maintenance anti-tumor necrosis factor-alpha therapy with infliximab for Crohn's disease

BACKGROUND

Clinical trials using infliximab have not reported cases of Pneumocystis carinii pneumonia (PCP), and PCP infection during standard medical treatment of inflammatory bowel disease is uncommon. Postmarketing surveillance through June of 2001 has identified 10 cases of PCP occurring during treatment with infliximab; 3 patients died.

CASE HISTORY

A 19-year-old man with Crohn's colitis developed thrush, leukopenia, fever, shortness of breath, and dry cough 21 months after initiating maintenance therapy with azathioprine and infliximab. Azathioprine had been at a stable dose of 75 mg per day (1 mg/kg) and the patient had received his 14th infusion of infliximab 4 weeks prior to presentation. Evaluation revealed the presence of Pneumocystis carinii on induced sputum. Azathioprine was discontinued, and the patient improved after initiating treatment with steroids and trimethoprim-sulfamethoxazole. Follow-up 2 weeks later confirmed clinical response to therapy.

CONCLUSIONS

This case report describes the uncommon occurrence of Pneumocystis pneumonia in the setting of maintenance therapy for Crohn's disease using infliximab and azathioprine. Mechanisms by which azathioprine and infliximab may impair the natural defense mechanisms against Pneumocystis are discussed.

Cumulative experience with short- and long-term toxicity to 6-mercaptopurine in the treatment of Crohn's disease and ulcerative colitis

BACKGROUND AND AIMS

The efficacy of 6-mercaptopurine (6-MP) in the treatment and long-term maintenance of remission of inflammatory bowel disease and prevention of recurrence after resection in Crohn's disease have been established. Concern about 6-MP toxicity remains, especially the development of neoplasm. The aim of this study is to determine the incidence of all short- and long-term toxicity by follow-up of all patients with inflammatory bowel disease treated with 6-MP over a 20-year period.

MATERIALS AND METHODS

We reviewed the office and hospital records and also determined the recent status of 410 patients with inflammatory bowel disease treated with 6-MP from 1980 to 1999. All toxicity was recorded.

RESULTS

There was a low incidence of early drug-related allergic reactions (3.9%) and pancreatitis (1.2%). Desensitization to either 6-MP or azathioprine is often successful with the same or the other drug. Significant leukopenia (<or=3500) was observed in 11.5%. In some cases, this was caused purposefully. Infectious complications occurred at different times during treatment with 6-MP in 14%, including pneumonia in 3.9% and herpes zoster in 3%. We now establish diabetes as a 6-MP-related complication. No significant difference in the incidence of neoplasm was seen from our earlier study or from patients not treated with 6-MP. We have now seen three lymphomas and two leukemias, again not greater in incidence than the overall inflammatory bowel disease population.

CONCLUSIONS

Our data support the long-term safety of 6-MP in the management of patients with inflammatory bowel disease. Earlier development of a neoplasm in a patient predisposed, without a change in incidence, remains possible.

Endogenous protectant kynurenic acid in amyotrophic lateral sclerosis

OBJECTIVES

Excitotoxicity may play a role in neurodegeneration in amyotrophic lateral sclerosis (ALS). Kynurenic acid (KYNA), an endogenous antagonist of excitatory amino acid receptors, may inhibit excitotoxic lesions. The aim of this study was to determine the concentration of KYNA in ALS patients.

MATERIAL AND METHODS

KYNA was measured by high-performance liquid chromatography in the serum and cerebrospinal fluid (CSF) from ALS and control patients.

RESULTS

Our study revealed that CSF KYNA concentration was significantly higher in patients with bulbar onset of ALS compared to controls, and compared to patients with limb onset of the disease. CSF KYNA was also higher in patients with severe clinical status compared to controls. Serum KYNA was significantly lower in ALS patients with severe clinical status compared to controls, and compared to patients with mild clinical status. There were no significant differences in CSF and serum KYNA concentration between the whole ALS group of patients and controls. There was no difference in CSF KYNA concentration between males and females, and there was no correlation between KYNA concentration and age of patients, and duration of ALS.

CONCLUSIONS

An increased CSF KYNA concentration in patients with bulbar onset of ALS and in patients with severe clinical status may indicate neuroprotective role of KYNA against excitotoxicity. The difference of KYNA concentration in CSF of patients with bulbar and limb onset of ALS suggests that these two variants of motor neuron disease may have different etiopathogenetic mechanisms.

Treatment of inflammatory bowel disease in childhood: best available evidence

The physician treating children with inflammatory bowel disease is confronted with a number of specific problems, one of them being the lack of randomized, controlled drug trials in children. In this review, the role of nutritional therapy is discussed with a focus on primary treatment, especially for children with Crohn's disease. Then, the available medical therapies are highlighted, reviewing the evidence of effectiveness and side effects in children, as compared with what is known in adults. Nutritional therapy has proven to be effective in inducing and maintaining remission in Crohn's disease while promoting linear growth. Conventional treatment consists of aminosalicylates and corticosteroids, whereas the early introduction of immunosuppressives (such as azathioprine or 6-mercaptopurine) is advocated as maintenance treatment. If these drugs are not tolerated or are ineffective, methotrexate may serve as an alternative in Crohn's disease. Cyclosporine is an effective rescue therapy in severe ulcerative colitis, but only will postpone surgery. A novel strategy to treat Crohn's disease is offered by infliximab, a monoclonal antibody to the proinflammatory cytokine tumor necrosis factor (TNF)-alpha. Based on the best-available evidence, suggested usage is provided for separate drugs with respect to dosage and monitoring of side effects in children.

Altered calcium in motoneurons by IgG from human motoneuron diseases

OBJECTIVES

The effect of IgG from patients with multifocal motor neuropathy (MMN) on the content and distribution of calcium in spinal motoneurons was compared with the effect of IgG from patients with sporadic amyotrophic lateral sclerosis (SALS) and IgG from normal individuals.

MATERIAL AND METHODS

Different purified IgG samples were injected intraperitoneally in mice. Then, the animals were subjected to histochemical techniques to visualize calcium in electron microscopic sections.

RESULTS

Quantitative morphometric analysis verified that IgG from MMN decreased the vesicular and axoplasmic calcium content in the axon terminals at the neuromuscular junctions and had no influence on the perikaryon. In contrast to this, IgG from patients with SALS increased the intracellular calcium both in the axon terminal and in the perikaryon. IgG from normal individuals exerted no effect. Elevated intracellular calcium may contribute to motoneuron degeneration. The lack of such effect with MMN immunoglobulins helps to explain the relative sparing of motoneurons in the disease.

Elevated levels of neurotrophins in human biceps brachii tissue of amyotrophic lateral sclerosis

Previous studies suggest that neurotrophins support regeneration and survival of injured motoneurons. Based on these findings, brain-derived neurotrophic factor (BDNF) has been clinically investigated for its therapeutic potential in amyotrophic lateral sclerosis (ALS), a rapidly progressing and fatal motoneuronal disease. We questioned whether imbalances of neurotrophic levels are indeed involved in the pathology of ALS. Therefore the expression of nerve growth factor (NGF), BDNF, neurotrophin-3 (NT-3), and neurotrophin-4/5 (NT-4/5) was investigated in postmortem muscle tissue of the biceps from 15 patients with neuropathologically confirmed sporadic ALS and 15 age-matched controls. Using mRNA analysis techniques and quantitative protein measurements, we have demonstrated that both mRNA and protein levels of all four neurotrophins are increased in muscle tissue of ALS patients. The production levels displayed a disease duration dependency and different expression patterns emerged for the four neurotrophins. Whereas the early phase of the disease was characterized by a strong upregulation of BDNF, levels of NGF, NT-3, and NT-4/5 gradually increased in the course of the disorder, peaking at later stages. We conclude that decreased neurotrophic support from muscle tissue is most likely not the cause of motoneuron degeneration in ALS. On the contrary, our results suggest that degenerating motoneurons in ALS are exposed to elevated levels of muscle-derived neurotrophins.

Cyclosporin therapy in severe ulcerative colitis: is it worth the effort?

PURPOSE

Cyclosporin is advocated in the treatment of acute severe ulcerative colitis that has failed to respond to high-dose corticosteroid therapy. This approach is controversial, with critics highlighting the temporary nature of remissions and the potential for adverse effects. There have been few reports of the long-term outcome of those patients who do respond. The purpose of this study was to investigate the clinical outcome of all patients treated with cyclosporin at our institution over the past five years.

METHODS

We conducted a retrospective study of 46 patients who presented to a tertiary referral center. Initial responders were those who avoided colectomy; a sustained response was defined as a remission that lasted while the patient was taking oral cyclosporin and for three months after this therapy was discontinued.

RESULTS

Thirty-two (69 percent) of 46 patients had an initial response to therapy, and 50 percent met criteria for a sustained response. Eleven of 23 sustained responders subsequently relapsed. At a mean of 22 months' follow-up, 26 percent of patients remain well and have never relapsed. Serious infective complications occurred in two patients, possibly attributable to therapy. No factors predictive of a likely response were identifiable on retrospective analysis.

CONCLUSIONS

This study confirms the efficacy of cyclosporin in the management of severe ulcerative colitis. Although many initial responders subsequently relapse, such patients may benefit from having even a short time to adjust to the need for surgery. A substantial minority (26 percent) of all patients treated remain in long-term remission.

Microglial activation and dopaminergic cell injury: an in vitro model relevant to Parkinson's disease

Microglial activation and oxidative stress are significant components of the pathology of Parkinson's disease (PD), but their exact contributions to disease pathogenesis are unclear. We have developed an in vitro model of nigral injury, in which lipopolysaccharide-induced microglial activation leads to injury of a dopaminergic cell line (MES 23.5 cells) and dopaminergic neurons in primary mesencephalic cell cultures. The microglia are also activated by PD IgGs in the presence of low-dose dopa-quinone- or H(2)O(2)-modified dopaminergic cell membranes but not cholinergic cell membranes. The activation requires the microglial FCgammaR receptor as demonstrated by the lack of activation with PD IgG Fab fragments or microglia from FCgammaR-/- mice. Although microglial activation results in the release of several cytokines and reactive oxygen species, only nitric oxide and H(2)O(2) appear to mediate the microglia-induced dopaminergic cell injury. These studies suggest a significant role for microglia in dopaminergic cell injury and provide a mechanism whereby immune/inflammatory reactions in PD could target oxidative injury relatively specifically to dopaminergic cells.

Brain-directed autoantibodies levels in the serum of Rett syndrome patients

Increased titer of brain-directed autoantibodies (AAB) may represent a risk for brain development in children with Rett syndrome (RTT). The aims of this work were to study the levels of brain-directed AAB, mainly nerve growth factor (NGF) and S-100 protein AAB, to analyze morphological features of brain labeling by AAB produced in RTT patients, and to correlate with clinical manifestation. The increased titer of anti-NGF AAB, but not of anti-S100 AAB has been determined in the blood of RTT patients. The blood from five RTT girls was investigated repeatedly (two to four times) within 0.5-3 years. In these RTT patients the level of anti-NGF AAB was stable, not depending on the stage of illness, so individual stability of anti-NGF AAB levels have been detected. However, the negative correlation between the level of these AAB and severity of disease has been found: girls with the milder course of illness (with relative preservation of speech and locomotor functions, later disease onset, and later development of regressive symptoms) were characterized by the higher levels of AAB. The study also revealed immunohistochemical labeling of neuronal population with serum from RTT patients. Serum AAB from RTT cases labeled the cytoplasm and apical dendrites of pyramidal neurons in the neocortex and hippocampus, neurons in basal ganglia and brain stem, but not in the cerebellum of rats. Our results show the presence of brain-directed AAB in blood serum of RTT patients, which suggests an autoimmune component in pathogenesis of RTT.

Glutamate uptake

Brain tissue has a remarkable ability to accumulate glutamate. This ability is due to glutamate transporter proteins present in the plasma membranes of both glial cells and neurons. The transporter proteins represent the only (significant) mechanism for removal of glutamate from the extracellular fluid and their importance for the long-term maintenance of low and non-toxic concentrations of glutamate is now well documented. In addition to this simple, but essential glutamate removal role, the glutamate transporters appear to have more sophisticated functions in the modulation of neurotransmission. They may modify the time course of synaptic events, the extent and pattern of activation and desensitization of receptors outside the synaptic cleft and at neighboring synapses (intersynaptic cross-talk). Further, the glutamate transporters provide glutamate for synthesis of e.g. GABA, glutathione and protein, and for energy production. They also play roles in peripheral organs and tissues (e.g. bone, heart, intestine, kidneys, pancreas and placenta). Glutamate uptake appears to be modulated on virtually all possible levels, i.e. DNA transcription, mRNA splicing and degradation, protein synthesis and targeting, and actual amino acid transport activity and associated ion channel activities. A variety of soluble compounds (e.g. glutamate, cytokines and growth factors) influence glutamate transporter expression and activities. Neither the normal functioning of glutamatergic synapses nor the pathogenesis of major neurological diseases (e.g. cerebral ischemia, hypoglycemia, amyotrophic lateral sclerosis, Alzheimer's disease, traumatic brain injury, epilepsy and schizophrenia) as well as non-neurological diseases (e.g. osteoporosis) can be properly understood unless more is learned about these transporter proteins. Like glutamate itself, glutamate transporters are somehow involved in almost all aspects of normal and abnormal brain activity.

Disturbances in the peripheral T-cell repertoire of patients with motor neuron disease: high levels of activation and indirect evidence of superantigen

Our data on peripheral blood T cells from Motor neuron disease (MND) patients indicate major immunological disturbances linked to this disease. Both CD4+ and CD8+ T-cell subsets display an increased fraction of cells showing activation markers compared to controls, indicating an unusually high level of activity in both populations. Likewise, an increased number of T-cell expansions were noted in MND patients compared to controls, most dramatically observed in the CD4+ T-cell subset, where 5/144 T-cell V genes analyzed in eight subjects turned out to be expanded in the peripheral blood. In the CD8+ T-cell subset, four out of eight MND patients had peripheral BV gene expansions, 9/144 V genes analyzed. However, the most interesting result was the observation that in three out eight MND patients, expansions concerning the same BV gene were present in both CD4+ and CD8+ subsets (BV8S1 in two and BV12S1 in one patient). Parallel expansions of BV-gene restricted populations in both CD4+ and CD8+ subsets in the same individual, in an major histocompatibility complex (MHC)-unrestricted manner, are normally limited to situations where superantigens are involved. No known superantigen has to date been described with the capacity to simultaneously stimulate both BV8S1 and BV12S1, suggesting that the postulated 'MND-associated' superantigen is a hitherto undefined molecule.