Free radicals in inflammatory neurological disease: increased lipid peroxidation and haptoglobin levels in Guillain Barré syndrome

Trauma-Related Guillain-Barré Syndrome: Systematic Review of an Emerging Concept

Guillain-Barré syndrome (GBS) is mainly associated with preceding exposure to an infectious agent, although the precise pathogenic mechanisms and causes remain unknown. Increasing evidence indicates an association between trauma-related factors and GBS. Here, we performed a systematic review, summarized the current scientific literature related to the onset of GBS associated with trauma, and explored the possible pathogenesis. A literature search of various electronic databases was performed up to May 2020 to identify studies reporting diverse trauma-related triggers of GBS. Data were extracted, summarized descriptively, and evaluated with respect to possible mechanisms. In total, 100 publications, including 136 cases and 6 case series involving GBS triggered by injury, surgery, intracranial hemorrhage, and heatstroke, met our eligibility criteria. The median age of the patients was 53 [interquartile range (IQR) 45-63] years, and 72.1% of the patients were male. The median number of days between the trigger to onset of GBS symptoms was 9 (IQR 6.5-13). Overall, 121 patients (89.0%) developed post-injury/surgical GBS, whereas 13 (9.6%) and 2 (1.5%) patients had preexisting spontaneous intracranial hemorrhage and heatstroke, respectively. The main locations of injury or surgeries preceding GBS were the spine and brain. Based on available evidence, we highlight possible mechanisms of GBS induced by these triggers. Moreover, we propose the concept of "trauma-related GBS" as a new research direction, which may help uncover more pathogenic mechanisms than previously considered for typical GBS triggered by infection or vaccination.

Immunomodulatory and anti-oxidative effect of the direct TRPV1 receptor agonist capsaicin on Schwann cells

Background

Only few studies describe the impact of nutritive factors on chronic inflammatory demyelinating polyneuropathy (CIDP), an inflammatory disease of the peripheral nervous system. The active component of chili pepper, capsaicin, is the direct agonist of the transient receptor potential channel vanilloid subfamily member 1. Its anti-inflammatory effect in the animal model experimental autoimmune neuritis (EAN) has been previously demonstrated.

Methods

In the present study, we describe the anti-inflammatory and anti-oxidative influence of capsaicin on Schwann cells (SCs) in an in vitro setting. Hereby, we analyze the effect of capsaicin on Schwann cells’ gene expression pattern, major histocompatibility complex class II (MHC-II) presentation, and H₂O₂-induced oxidative stress. Furthermore, the effect of capsaicin on myelination was examined in a SC-dorsal root ganglia (DRG) coculture by myelin basic protein staining. Finally, in order to investigate the isolated effect of capsaicin on SCs in EAN pathology, we transplant naïve and capsaicin pre-treated SCs intrathecally in EAN immunized rats and analyzed clinical presentation, electrophysiological parameters, and cytokine expression in the sciatic nerve.

Results

In SC monoculture, incubation with capsaicin significantly reduces interferon gamma-induced MHC-II production as well as toll-like receptor 4 and intercellular adhesion molecule 1 mRNA expression. Calcitonin gene-related peptide mRNA production is significantly upregulated after capsaicin treatment. Capsaicin reduces H₂O₂-induced oxidative stress in SC in a preventive, but not therapeutic setting. In a SC-DRG coculture, capsaicin does not affect myelination rate. After intrathecal transplantation of naïve and capsaicin pre-treated SCs in EAN-immunized rats, naïve, but not capsaicin pre-treated intrathecal SCs, ameliorated EAN pathology in rats.

Conclusions

In conclusion, we were able to demonstrate a direct immunomodulatory and anti-oxidative effect of capsaicin in a SC culture by reduced antigen presentation and expression of an anti-inflammatory profile. Furthermore, capsaicin increases the resistance of SCs against oxidative stress. A primary effect of capsaicin on myelination was not proven. These results are in concordance with previous data showing an anti-inflammatory effect of capsaicin, which might be highly relevant for CIDP patients.

Alterations of plasma concentrations of lipophilic antioxidants are associated with Guillain-Barre syndrome

BACKGROUND

Guillain-Barré syndrome (GBS) is an acute inflammatory polyneuropathy resulting in demyelination in peripheral nervous system. Myelin enriched in lipids is easily oxidized by reactive oxygen species during inflammation. Oxidative stress and lipophilic anti-oxidative capacities in GBS patients have not been fully explored. To evaluate the redox status of GBS patients, we measured malondialdehyde (MDA), myeloperoxidase (MPO), lipophilic antioxidants, and tocopherols concentrations in plasma from GBS patients and age-matched healthy controls.

RESULTS

Concentrations of γ-tocopherol and δ-tocopherol decreased significantly, and α-carotene significantly increased in GBS patients compared to healthy controls. However, no significant changes in MDA and MPO concentrations were detected. In GBS patients, the γ-tocopherol concentration correlated positively with concentrations of δ-tocopherol, α-tocopherol, lutein, Q10, and γ-CEHC, respectively. Similarly, the δ-tocopherol concentration correlated positively with γ-tocopherol, α-tocopherol, lutein, Q10, δ-CEHC, and γ-CEHC concentrations, respectively. The receiver operating characteristics curve analysis showed that γ-tocopherol may serve as a good predictor for GBS.

CONCLUSIONS

Diminished lipophilic antioxidant defense, mainly γ-tocopherol and δ-tocopherol, in GBS patients accounting for their lowered resistance to reactive oxygen species is probably associated with pathogenesis of GBS, and potentially useful for the development of therapeutic strategies.

Mining the fecal proteome: from biomarkers to personalised medicine

INTRODUCTION

Fecal proteomics has gained increased prominence in recent years. It can provide insights into the diagnosis and surveillance of many bowel diseases by both identifying potential biomarkers in stool samples and helping identify disease-related pathways. Fecal proteomics has already shown its potential for the discovery and validation of biomarkers for colorectal cancer screening, and the analysis of fecal microbiota by MALDI-MS for the diagnosis of a range of bowel diseases is gaining clinical acceptance. Areas covered: Based on a comprehensive analysis of the current literature, we introduce the range of sensitive and specific proteomics methods which comprise the current 'Proteomics Toolbox', explain how the integration of fecal proteomics with data processing/bioinformatics has been used for the identification of potential biomarkers for both CRC and other gut-related pathologies and analysis of the fecal microbiome, outline some of the current fecal assays in current clinical practice and introduce the concept of personalised medicine which these technologies will help inform. Expert commentary: Integration of fecal proteomics with other proteomics and genomics strategies as well as bioinformatics is paving the way towards personalised medicine, which will bring with it improved global healthcare.

Changes in Serum Ceruloplasmin Levels Based on Immunomodulatory Treatments and Melatonin Supplementation in Multiple Sclerosis Patients

BACKGROUND The cause of multiple sclerosis (MS) is currently unknown, but it is thought that oxidative damage and iron metabolism mechanisms are involved. The aim of this study was to examine ceruloplasmin concentration in MS patients based on various immunomodifying therapies and to test the effect of antioxidative melatonin on ceruloplasmin levels. MATERIAL AND METHODS This prospective study included 102 MS patients and 15 healthy controls. Patients were divided into groups according to different immunomodifying therapies: interferons beta 1a, interferons beta 1b, glatiramer acetate, mitoxantrone, and immunomodifying pre-treatment (A, B, G, Mx, and P groups, respectively), and the relapse R group. MS patients were supplemented with melatonin for 3 months. Serum ceruloplasmin concentrations, EDSS, brain MRI, serum C-reactive protein level, and white blood cell count were examined. RESULTS The results indicated significantly increased levels of ceruloplasmin in MS patients. No differences in ceruloplasmin concentrations between the relapse group and controls were observed. In A and G groups, ceruloplasmin levels before and after melatonin were similar to levels in controls. In group B, ceruloplasmin concentration was significantly higher vs. control and relapse groups. After melatonin administration in group B, ceruloplasmin levels decreased. Ceruloplasmin concentrations in the Mx group were significantly higher compared to controls. CONCLUSIONS We found for the first time that ceruloplasmin concentration in MS patients varies depending on different immunomodulatory treatment and decrease after 3 months of melatonin administration. Ceruloplasmin could be a valuable serum marker for the chronic demyelinating process participating in oxidative stress mechanisms, as well as a neurodegenerative marker, but not a marker of acute-phase MS.

Increased levels of lipid hydroperoxides in plasma of patients with multiple sclerosis: a relationship with paraoxonase activity

Paraoxonase, an enzyme associated with high density lipoproteins (HDL), plays an important role in the anti-oxidant and anti-inflammatory properties exerted by HDL. Increasing evidence supports a role of free radicals and oxidative stress in the inflammatory processes and in the pathogenesis of multiple sclerosis (MS). The aim of this study was to further investigate the relationship between oxidative damage and MS; therefore we compared the paraoxonase activity and levels of cholesteryl ester hydroperoxides (CE-OOH), as marker of lipid peroxidation, in plasma isolated from healthy subjects (n=89) and from MS patients (n=24) in the early stage disability (EDSSB<3.5). Our results demonstrated for the first time that the activity of paraoxonase in the plasma of MS subjects was significantly lower with respect to controls (p<0.001). Moreover, our results showed a significant increase in the levels of CE-OOH in plasma from MS subjects (p<0.001). CE-OOH are biologically active substances derived from the oxidation of cholesteryl ester localized in the hydrophobic core of plasma lipoproteins (HDL, LDL). Therefore, our study demonstrates alterations of lipoprotein peroxidation in MS and provides further evidence that oxidative stress and impairment of the anti-oxidant system may play a role in MS.

Oxidative Stress in the Hypothalamus: the Importance of Calcium Signaling and Mitochondrial ROS in Body Weight Regulation

A considerable amount of evidence shows that reactive oxygen species (ROS) in the mammalian brain are directly responsible for cell and tissue function and dysfunction. Excessive reactive oxygen species contribute to various conditions including inflammation, diabetes mellitus, neurodegenerative diseases, tumor formation, and mental disorders such as depression. Increased intracellular calcium levels have toxic roles leading to cell death. However, the exact connection between reactive oxygen production and high calcium stress is not yet fully understood. In this review, we focus on the role of reactive oxygen species and calcium stress in hypothalamic arcuate neurons controlling feeding. We revisit the role of NPY and POMC neurons in the regulation of appetite and energy homeostasis, and consider how ROS and intracellular calcium levels affect these neurons. These novel insights give a new direction to research on hypothalamic mechanisms regulating energy homeostasis and may offer novel treatment strategies for obesity and type-2 diabetes.

Zonulin and its regulation of intestinal barrier function: the biological door to inflammation, autoimmunity, and cancer

The primary functions of the gastrointestinal tract have traditionally been perceived to be limited to the digestion and absorption of nutrients and to electrolytes and water homeostasis. A more attentive analysis of the anatomic and functional arrangement of the gastrointestinal tract, however, suggests that another extremely important function of this organ is its ability to regulate the trafficking of macromolecules between the environment and the host through a barrier mechanism. Together with the gut-associated lymphoid tissue and the neuroendocrine network, the intestinal epithelial barrier, with its intercellular tight junctions, controls the equilibrium between tolerance and immunity to non-self antigens. Zonulin is the only physiological modulator of intercellular tight junctions described so far that is involved in trafficking of macromolecules and, therefore, in tolerance/immune response balance. When the finely tuned zonulin pathway is deregulated in genetically susceptible individuals, both intestinal and extraintestinal autoimmune, inflammatory, and neoplastic disorders can occur. This new paradigm subverts traditional theories underlying the development of these diseases and suggests that these processes can be arrested if the interplay between genes and environmental triggers is prevented by reestablishing the zonulin-dependent intestinal barrier function. This review is timely given the increased interest in the role of a "leaky gut" in the pathogenesis of several pathological conditions targeting both the intestine and extraintestinal organs.

Serum and cerebrospinal fluid antioxidant activity and lipid peroxidation in Guillain-Barre syndrome and multiple sclerosis patients

Oxidative stress through the changes in the levels of reactive oxygen species and antioxidative parameters can cause various neurological disorders. The aim of the present study was to show antioxidant activity (AOA) and malondialdehyde (MDA) levels in affected people with Guillain-Barre syndrome (GBS) and multiple sclerosis (MS). A total of 15 GBS patients, 13 MS patients, and 15 age and sex matched controls were included in this study. MDA and AOA values were determined in both cerebrospinal fluid (CSF) and serum, spectrophotometrically. We have shown an increase in the values of MDA in the CSF of both GBS and MS patients (0.32 +/- 0.073 and 0.22 +/- 0.06 micromol/L) compared to the control (undetectable levels). Furthermore, a significant decrease in the serum MDA levels was shown in both GBS and MS patients (0.81 +/- 0.18 and 0.73 +/- 0.18 micromol/L) when compared to the control (1.7 +/- 0.46 micromol/L). A decrease was shown for serum AOA in both GBS (1.7 +/- 0.21 mmol/L) and MS patients (2.6 +/- 0.62 mmol/L) when compared to the control (3.2 +/- 0.17 mmol/L). However, a significant increase in the values of CSF AOA was shown in both MS and GBS patients (1.47 +/- 0.19 and 1.42 +/- 0.26 mmol/L) compared to the control (0.71 +/- 0.19 mmol/L). An imbalance between the levels of AOA and MDA in both CSF and serum can be followed in both MS and GBS patients.

Measurements of oxidative stress status and antioxidant activity in chronic leukaemia patients

There is an interactive relationship between leukaemia and oxidative stress. Leukaemic cells produce larger amounts of reactive oxygen species (ROS) than non-leukaemic cells as they are under a continual state of oxidative siege. So, this study was performed on 20 patients with chronic leukaemia from the Oncology Centre, Mansoura University. We measured leucocytic H2O2 concentrations and lipid peroxidation as serum malondialdehyde (MDA) concentration, serum total antioxidant activity, plasma ascorbic acid and dehydroascorbic acid concentrations, blood reduced glutathione concentration, haemolysate G6PD activity, blood catalase activity, serum superoxide dismutase (SOD) activity and serum anti-dsDNA concentration. We found that chronic leukaemia patients showed a significant increase (P &lt; 0.05) in leucocytic H2O2, serum MDA concentration and total anti-oxidant activity either before or after treatment as compared with control group. Also, there was a significant increase in the other parameters (glutathione, catalase and SOD) either before or after treatment, but we found a significant decrease in ascorbic acid concentration and G6PD activity. There was a significant increase in anti-dsDNA concentration either before or after treatment. It can be concluded that leukaemic patients produce larger amounts of ROS than non-leukaemic patients. Also, the increase in antioxidant activity in leukaemic patients is not high enough to counteract the harmful effects of free radicals. This scenario becomes worse after administration of chemotherapy.

Haptoglobin study in myasthenia gravis

OBJECTIVE: A cross-sectional study of haptoglobin (Hp) in myasthenia gravis (MG) was designed, with the objective to identify its values and correlate them with different disease status. METHOD: 46 patients were enrolled in the study, all having disease severity established according to the quantitative myasthenia gravis strength scores (QMGSS). Based on the functional scale determined by Myasthenia Gravis Foundation of America (MGFA) recommendations, patients were classified as having: complete stable remission (CSR; n=10); minimal manifestations-0 (MM0; n=6), minimal manifestations-1 (MM1; n=4); pharmacological remission (PR; n=6). Two other groups participated: thymomatous patients (T; n=10) and patients without imunosuppression or thymectomy, until the assessment for Hp (WIT; n=10). Hp dosage was done by immunonephelometry, blindly to clinical data. Student's t-test, Anova test and linear regression were employed for statistical analyses. RESULTS: Statistically significant differences occurred between CSR+MM0xWIT groups (86.62x157.57, p<0.001) and PR+MM1xWIT groups (73.93x157.57, p<0.001). Linear regression showed correlation between Hp levels and QMGSS (r=0.759, p<0.001). CONCLUSION: Our results suggest that Hp may be useful in clinical practice as a disease severity marker in MG.

Identification of disease-related biomarkers by proteome analysis of cerebrospinal fluid in Guillain–Barré syndrome

Evaluation of: Jin T, Hu LS, Chang M, Wu J, Winblad B, Zhu J: Proteomic identification of potential protein markers in cerebrospinal fluid of GBS patients. Eur. J. Neurol. 14(5), 563–568 (2007). This study aimed to identify disease-related biomarkers in cerebrospinal fluid (CSF) from patients with Guillain–Barré syndrome (GBS) using the proteomic analysis 2D difference in gel electrophoresis. Six different protein levels were found to be changed in CSF of GBS patients as compared with controls. Haptoglobin, ApoA-IV and an unnamed protein (PRO2044) were increased in CSF of GBS patients, while transthyretin, ApoE and fibrinogen were found to be decreased. The significance of these proteins remains to be further evaluated by quantitative assays and by taking into account disease-related variables such as blood–CSF barrier function and subtype of GBS.

Proteomic identification of potential protein markers in cerebrospinal fluid of GBS patients

Increased protein level in the cerebrospinal fluid (CSF) is a characteristic of patients with Guillain-Barré syndrome (GBS), an acute inflammatory autoimmune disorder in the peripheral nervous system (PNS). However, the molecular mechanisms underlying the disease remain poorly understood and so far no reliable disease-related markers are available. By comparing the CSF proteome of GBS patients with control subjects suffering from other neurological disorders, it may be possible to identify proteins that involve in the disease process and thus to study the pathogenesis of GBS. We used two-dimensional difference gel electrophoresis (2D DIGE) technique, in combination with matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS), to determine the abnormal CSF proteins in GBS patients. Our data showed that the levels of six proteins and their isoforms in CSF were significantly altered in GBS patients compared with controls. Haptoglobin, apolipoprotein A-IV and PRO2044 (unnamed protein) were considerably increased in the CSF of GBS patients, whereas transthyretin, apolipoprotein E and fibrinogen were considerably decreased. We concluded that these six proteins may be involved in the pathogenesis of GBS and call for further studying the role of these proteins in the pathogenesis of the disease.

Demyelination: the role of reactive oxygen and nitrogen species

This review summarises the role that reactive oxygen and nitrogen species play in demyelination, such as that occurring in the inflammatory demyelinating disorders multiple sclerosis and Guillain-Barré syndrome. The concentrations of reactive oxygen and nitrogen species (e.g. superoxide, nitric oxide and peroxynitrite) can increase dramatically under conditions such as inflammation, and this can overwhelm the inherent antioxidant defences within lesions. Such oxidative and/or nitrative stress can damage the lipids, proteins and nucleic acids of cells and mitochondria, potentially causing cell death. Oligodendrocytes are more sensitive to oxidative and nitrative stress in vitro than are astrocytes and microglia, seemingly due to a diminished capacity for antioxidant defence, and the presence of raised risk factors, including a high iron content. Oxidative and nitrative stress might therefore result in vivo in selective oligodendrocyte death, and thereby demyelination. The reactive species may also damage the myelin sheath, promoting its attack by macrophages. Damage can occur directly by lipid peroxidation, and indirectly by the activation of proteases and phospholipase A2. Evidence for the existence of oxidative and nitrative stress within inflammatory demyelinating lesions includes the presence of both lipid and protein peroxides, and nitrotyrosine (a marker for peroxynitrite formation). The neurological deficit resulting from experimental autoimmune demyelinating disease has generally been reduced by trial therapies intended to diminish the concentration of reactive oxygen species. However, therapies aimed at diminishing reactive nitrogen species have had a more variable outcome, sometimes exacerbating disease.

Free radical toxicity and antioxidants in Guillain–Barre syndrome, a preliminary study

BACKGROUND

The generation of reactive oxygen species (ROS) has been implicated in the pathogenesis of a vast array of disease processes including some neurological disorders.

METHOD

Ten patients with Guillain-Barre syndrome (GBS) and 10 age and sex-matched controls were included in this study. The erythrocyte glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) levels, as well as plasma antioxidant vitamins C and E and serum glutathione-S-transferase (GST) levels were estimated spectrophotometrically.

RESULTS

The plasma vitamin E and the serum total glutathione-S-transferase levels were markedly increased in both pre- and post-treated cases of GBS when compared to controls. The erythrocyte glutathione and malondialdehyde levels were significantly reduced in GBS cases when compared to normals. However, plasma vitamin C and erythrocyte superoxide dismutase were not altered when compared to controls.

CONCLUSION

Free radical toxicity may have an influence in patients suffering from GBS.

Antioxidant status, erythrocyte membrane lipid peroxidation and osmotic fragility in malignant lymphoma patients

We studied erythrocyte and leukocyte superoxide dismutase and catalase activities, erythrocyte malondialdehyde (MDA) and osmotic fragility and plasma L-ascorbic acid and L-dehydroascorbic acid levels in adult patients with acute lymphoblastic leukemia (ALL), Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) before and after treatment. SOD activity was elevated in leukocytes of ALL and HD patients before treatment, and borderlike-significantly elevated in leukocytes of the same patients after treatment in comparison to the control subjects. SOD activity was not changed in NHL patients before or after chemotherapy. Erythrocyte superoxide dismutase and catalase activities were elevated in the three groups of lymphomas before and after treatment. MDA level and osmotic fragility of red blood cells of patients with lymphomas were increased before and after treatment in comparison to the control group. Plasma L-ascorbic acid concentrations were decreased, whereas L-dehydroascorbic acid concentrations were increased in ALL, HD and NHL patients before and after treatment. There were also significant differences in the activities of the antioxidant enzymes, concentrations of antioxidants, MDA and osmotic fragility in the most of the malignant lymphoma patients. The present data suggest that hematological complications and autoimmune hemolytic anemia might be attributed to the oxidative stress produced by malignant lymphomas.