Autoimmune diseases of the spine and spinal cord

Magnetic resonance imaging (MRI) and clinicopathological tools have led to the identification of a wide spectrum of autoimmune entities that involve the spine. A clearer understanding of the unique imaging features of these disorders, along with their clinical presentations, will prove invaluable to clinicians and potentially limit the need for more invasive procedures such as tissue biopsies. Here, we review various autoimmune diseases affecting the spine and highlight salient imaging features that distinguish them radiologically from other disease entities.

Autoimmune disease of head and neck, imaging, and clinical review

Autoimmune disease of the head and neck (H&N) could be primary or secondary to systemic diseases, medications, or malignancies. Immune-mediated diseases of the H&N are not common in daily practice of radiologists; the diagnosis is frequently delayed because of the non-specific initial presentation and lack of familiarity with some of the specific imaging and clinical features. In this review, we aim to provide a practical diagnostic approach based on the specific radiological findings for each disease. We hope that our review will help radiologists expand their understanding of the spectrum of the discussed disease entities, help them narrow the differential diagnosis, and avoid unnecessary tissue biopsy when appropriate based on the specific clinical scenarios.

Autoimmune diseases of the brain, imaging and clinical review

There is an extensive spectrum of autoimmune entities that can involve the central nervous system, which has expanded with the emergence of new imaging modalities and several clinicopathologic entities. Clinical presentation is usually non-specific, and imaging has a critical role in the workup of these diseases. Immune-mediated diseases of the brain are not common in daily practice for radiologists and, except for a few of them such as multiple sclerosis, there is a vague understanding about differentiating them from each other based on the radiological findings. In this review, we aim to provide a practical diagnostic approach based on the unique radiological findings for each disease. We hope our diagnostic approach will help radiologists expand their basic understanding of the discussed disease entities and narrow the differential diagnosis in specific clinical scenarios. An understanding of unique imaging features of these disorders, along with laboratory evaluation, may enable clinicians to decrease the need for tissue biopsy.

Primed mesenchymal stem cells package exosomes with metabolites associated with immunomodulation

Mesenchymal stem cell (MSC) based therapies are currently being evaluated as a putative therapeutic in numerous human clinical trials. Recent reports have established that exosomes mediate much of the therapeutic properties of MSCs. Exosomes are nanovesicles which mediate intercellular communication, transmitting signals between cells which regulate a diverse range of biological processes. MSC-derived exosomes are packaged with numerous types of proteins and RNAs, however, their metabolomic and lipidomic profiles to date have not been well characterized. We previously reported that MSCs, in response to priming culture conditions that mimic the in vivo microenvironmental niche, substantially modulate cellular signaling and significantly increase the secretion of exosomes. Here we report that MSCs exposed to such priming conditions undergo glycolytic reprogramming, which homogenizes MSCs' metabolomic profile. In addition, we establish that exosomes derive from primed MSCs are packaged with numerous metabolites that have been directly associated with immunomodulation, including M2 macrophage polarization and regulatory T lymphocyte induction.

Exosomes Derived from Human Primed Mesenchymal Stem Cells Induce Mitosis and Potentiate Growth Factor Secretion

Mesenchymal stem cells (MSCs) facilitate functional recovery in numerous animal models of inflammatory and ischemic tissue-related diseases with a growing body of research suggesting that exosomes mediate many of these therapeutic effects. It remains unclear, however, which types of proteins are packaged into exosomes compared with the cells from which they are derived. In this study, using comprehensive proteomic analysis, we demonstrated that human primed MSCs secrete exosomes (pMEX) that are packaged with markedly higher fractions of specific protein subclasses compared with their cells of origin, indicating regulation of their contents. Notably, we found that pMEX are also packaged with substantially elevated levels of extracellular-associated proteins. Fibronectin was the most abundant protein detected, and data established that fibronectin mediates the mitogenic properties of pMEX. In addition, treatment of SHSY5Y cells with pMEX induced the secretion of growth factors known to possess mitogenic and neurotrophic properties. Taken together, our comprehensive analysis indicates that pMEX are packaged with specific protein subtypes, which may provide a molecular basis for their distinct functional properties.

Phase 2 Trial of Ibudilast in Progressive Multiple Sclerosis

BACKGROUND

There are limited treatments for progressive multiple sclerosis. Ibudilast inhibits several cyclic nucleotide phosphodiesterases, macrophage migration inhibitory factor, and toll-like receptor 4 and can cross the blood-brain barrier, with potential salutary effects in progressive multiple sclerosis.

METHODS

We enrolled patients with primary or secondary progressive multiple sclerosis in a phase 2 randomized trial of oral ibudilast (≤100 mg daily) or placebo for 96 weeks. The primary efficacy end point was the rate of brain atrophy, as measured by the brain parenchymal fraction (brain size relative to the volume of the outer surface contour of the brain). Major secondary end points included the change in the pyramidal tracts on diffusion tensor imaging, the magnetization transfer ratio in normal-appearing brain tissue, the thickness of the retinal nerve-fiber layer, and cortical atrophy, all measures of tissue damage in multiple sclerosis.

RESULTS

Of 255 patients who underwent randomization, 129 were assigned to ibudilast and 126 to placebo. A total of 53% of the patients in the ibudilast group and 52% of those in the placebo group had primary progressive disease; the others had secondary progressive disease. The rate of change in the brain parenchymal fraction was -0.0010 per year with ibudilast and -0.0019 per year with placebo (difference, 0.0009; 95% confidence interval, 0.00004 to 0.0017; P=0.04), which represents approximately 2.5 ml less brain-tissue loss with ibudilast over a period of 96 weeks. Adverse events with ibudilast included gastrointestinal symptoms, headache, and depression.

CONCLUSIONS

In a phase 2 trial involving patients with progressive multiple sclerosis, ibudilast was associated with slower progression of brain atrophy than placebo but was associated with higher rates of gastrointestinal side effects, headache, and depression. (Funded by the National Institute of Neurological Disorders and Stroke and others; NN102/SPRINT-MS ClinicalTrials.gov number, NCT01982942 .).

Treatment of γ-aminobutyric acid B receptor-antibody autoimmune encephalitis with oral corticosteroids

BACKGROUND

Autoimmune encephalitis is increasingly identified as a cause of nonviral, idiopathic encephalitis. Present treatment algorithms recommend costly immune-modulating treatments and do not identify a role for oral corticosteroids.

OBJECTIVE

To present a patient with γ-aminobutyric acid(B) receptor-antibody encephalitis before and after treatment with oral corticosteroids.

DESIGN

Case report.

SETTING

The inpatient course as well as outpatient follow-up is discussed.

PATIENT

A 43-year-old man with initial presentation of seizures and altered mental status.

INTERVENTION

Our patient was treated with an extended course of oral corticosteroids as an outpatient.

RESULTS

After treatment with oral corticosteroids, our patient had steady clinical improvement, achieved seizure freedom, and experienced improved mental status to within normal limits.

CONCLUSIONS

This case supports the use of low-cost oral corticosteroids in treating patients with γ-aminobutyric acid(B) receptor-antibody encephalitis.

Identification and validation of suitable endogenous reference genes for gene expression studies in human peripheral blood

BACKGROUND

Gene expression studies require appropriate normalization methods. One such method uses stably expressed reference genes. Since suitable reference genes appear to be unique for each tissue, we have identified an optimal set of the most stably expressed genes in human blood that can be used for normalization.

METHODS

Whole-genome Affymetrix Human 2.0 Plus arrays were examined from 526 samples of males and females ages 2 to 78, including control subjects and patients with Tourette syndrome, stroke, migraine, muscular dystrophy, and autism. The top 100 most stably expressed genes with a broad range of expression levels were identified. To validate the best candidate genes, we performed quantitative RT-PCR on a subset of 10 genes (TRAP1, DECR1, FPGS, FARP1, MAPRE2, PEX16, GINS2, CRY2, CSNK1G2 and A4GALT), 4 commonly employed reference genes (GAPDH, ACTB, B2M and HMBS) and PPIB, previously reported to be stably expressed in blood. Expression stability and ranking analysis were performed using GeNorm and NormFinder algorithms.

RESULTS

Reference genes were ranked based on their expression stability and the minimum number of genes needed for nomalization as calculated using GeNorm showed that the fewest, most stably expressed genes needed for acurate normalization in RNA expression studies of human whole blood is a combination of TRAP1, FPGS, DECR1 and PPIB. We confirmed the ranking of the best candidate control genes by using an alternative algorithm (NormFinder).

CONCLUSION

The reference genes identified in this study are stably expressed in whole blood of humans of both genders with multiple disease conditions and ages 2 to 78. Importantly, they also have different functions within cells and thus should be expressed independently of each other. These genes should be useful as normalization genes for microarray and RT-PCR whole blood studies of human physiology, metabolism and disease.

Corticosteroid effects on blood gene expression in Duchenne muscular dystrophy

Though Deflazacort and prednisone improve clinical endpoints in Duchenne muscular dystrophy (DMD) patients, Deflazacort produces fewer side effects. As mechanisms of improvement and side effect differences remain unknown, we evaluated effects of corticosteroid administration on gene expression in blood of DMD patients. Whole blood was obtained from 14 children and adolescents with DMD treated with corticosteroids (DMD-STEROID) and 20 DMD children and adolescents naïve to corticosteroids (DMD). The DMD-STEROID group was further subdivided into Deflazacort and prednisone groups. Affymetrix U133 Plus 2.0 expression microarrays were used to evaluate mRNA expression. Expression of 524 probes changed with corticosteroids, including genes in iron trafficking and the chondroitin sulfate biosynthesis pathway. Deflazacort compared with prednisone yielded 508 regulated probes, including many involved in adipose metabolism. These genes and pathways help explain mechanisms of efficacy and side effects of corticosteroids, and could provide new treatment targets for DMD and other neuromuscular disorders.

Gene expression in peripheral blood differs after cardioembolic compared with large-vessel atherosclerotic stroke: biomarkers for the etiology of ischemic stroke

There are no biomarkers that differentiate cardioembolic from large-vessel atherosclerotic stroke, although the treatments differ for each and approximately 30% of strokes and transient ischemic attacks have undetermined etiologies using current clinical criteria. We aimed to define gene expression profiles in blood that differentiate cardioembolic from large-vessel atherosclerotic stroke. Peripheral blood samples were obtained from healthy controls and acute ischemic stroke patients (<3, 5, and 24 h). RNA was purified, labeled, and applied to Affymetrix Human U133 Plus 2.0 Arrays. Expression profiles in the blood of cardioembolic stroke patients are distinctive from those of large-vessel atherosclerotic stroke patients. Seventy-seven genes differ at least 1.5-fold between them, and a minimum number of 23 genes differentiate the two types of stroke with at least 95.2% specificity and 95.2% sensitivity for each. Genes regulated in large-vessel atherosclerotic stroke are expressed in platelets and monocytes and modulate hemostasis. Genes regulated in cardioembolic stroke are expressed in neutrophils and modulate immune responses to infectious stimuli. This new method can be used to predict whether a stroke of unknown etiology was because of cardioembolism or large-vessel atherosclerosis that would lead to different therapy. These results have wide ranging implications for similar disorders.

Genomic Profiles of Stroke in Blood

These studies show that gene expression changes in most patients by 2 to 3 hours after ischemic stroke, and in all patients studied by 24 hours.

The future of genomic profiling of neurological diseases using blood

Sequencing of the human genome and new microarray technology make it possible to assess all genes on a single chip or array. Recent studies show different patterns of gene expression related to different tissues and diseases, and these patterns of gene expression are beginning to be used for diagnosis and treatment decisions in various types of lymphoid and solid malignancies. Because of obvious problems obtaining brain tissue, progress in genomics of neurological diseases has been slow. To address this, we demonstrated that different types of acute injury in rodent brain produced different patterns of gene expression in peripheral blood. These animal studies have now been extended to human studies. Two groups have shown that there are specific genomic profiles in the blood of patients after ischemic stroke that are highly sensitive and specific for predicting stroke. Other recent studies demonstrate specific genomic profiles in the blood of patients with Down syndrome, neurofibromatosis, tuberous sclerosis, Huntington disease, multiple sclerosis, Tourette syndrome, and others. In addition, data demonstrate specific profiles of gene expression in the blood related to different drugs, toxins, and infections. Although all of these studies are still preliminary basic scientific endeavors, they suggest that this approach will have clinical applications to neurological diseases in humans.

Genomics of brain and blood: progress and pitfalls

Gene expression profiles in brain and blood of animals and humans can be useful for diagnosis, prognosis, and treatment of epilepsy. This article reviews recent progress and prospects for the future.

Psychogenic nonepileptic seizures are associated with an increased risk of obesity

Psychogenic nonepileptic seizures (NES) are somatic manifestations of psychological distress. There is some evidence that weight problems are more common in patients with psychiatric illness. We have observed that patients admitted for video-EEG monitoring who we diagnosed with NES commonly have a larger body habitus than patients with epilepsy. The goal of this study was to test our hypothesis that there was a significant difference in body mass index (BMI) in patients with nonepileptic seizures compared with their epileptic counterparts. We compared the BMIs of 46 NES patients and 46 age- and gender-matched epileptic controls and found that the NES patients had significantly higher BMIs (30.5 vs 26.1, P=0.006) than controls. This remained true after controlling for weight-gain properties of antiepileptic drugs. These results are compared with the prevalence of overweight and obesity in the general population. Possible explanations of the findings and limitations of the study are discussed.

Levetiracetam monotherapy for elderly patients with epilepsy

We retrospectively identified 14 elderly patients with a history of partial seizures who received levetiracetam (LEV) monotherapy. Patients began LEV either as first line therapy (n=5) or were converted to LEV monotherapy (n=9) after failing prior antiepileptic medications (AEDs). Thirteen patients continued on LEV monotherapy for at least 6 months. One patient was lost to follow-up. Eight patients (61.5%) became seizure free. Four patients who began LEV as a first line therapy became seizure free, whereas the remaining four patients who converted to LEV after they failed their previous AEDs became seizure free. Four patients (30.7%) had more than a 50% seizure reduction of seizures. Only one patient had no significant change in seizure frequency after started on LEV. The total dosages used to control seizures were 500-3000 mg/day, (mean 1839.2 mg/day). LEV monotherapy can be effective and well tolerated in this group of patients. A prospective, larger, double blind monotherapy study is needed to confirm this finding.

Citron binds to PSD-95 at glutamatergic synapses on inhibitory neurons in the hippocampus

Synaptic NMDA-type glutamate receptors are anchored to the second of three PDZ (PSD-95/Discs large/ZO-1) domains in the postsynaptic density (PSD) protein PSD-95. Here, we report that citron, a protein target for the activated form of the small GTP-binding protein Rho, preferentially binds the third PDZ domain of PSD-95. In GABAergic neurons from the hippocampus, citron forms a complex with PSD-95 and is concentrated at the postsynaptic side of glutamatergic synapses. Citron is expressed only at low levels in glutamatergic neurons in the hippocampus and is not detectable at synapses onto these neurons. In contrast to citron, p135 SynGAP, an abundant synaptic Ras GTPase-activating protein that can bind to all three PDZ domains of PSD-95, and Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) are concentrated postsynaptically at glutamatergic synapses on glutamatergic neurons. CaM kinase II is not expressed and p135 SynGAP is expressed in less than half of hippocampal GABAergic neurons. Segregation of citron into inhibitory neurons does not occur in other brain regions. For example, citron is expressed at high levels in most thalamic neurons, which are primarily glutamatergic and contain CaM kinase II. In several other brain regions, citron is present in a subset of neurons that can be either GABAergic or glutamatergic and can sometimes express CaM kinase II. Thus, in the hippocampus, signal transduction complexes associated with postsynaptic NMDA receptors are different in glutamatergic and GABAergic neurons and are specialized in a way that is specific to the hippocampus.

A yeast protein, homologous to the proteolipid of the chromaffin granule proton-ATPase, is important for cell growth

We have characterized a gene, PPA1, adjacent to the yeast MAS2 gene. DNA sequence analysis of PPA1 predicts a hydrophobic protein of 23 kDa. This protein is homologous to the proteolipid of the bovine chromaffin granule proton ATPase and to the proteolipid of the yeast vacuolar proton ATPase. Gene disruption experiments indicate that the PPA1 protein is essential for viability in three unrelated yeast strains and important for optimal growth in a fourth strain.