Intrathecal levels of matrix metalloproteinases in systemic lupus erythematosus with central nervous system engagement

Biomarkers for systemic lupus erythematosus - a focus on organ damage

INTRODUCTION

Systemic lupus erythematosus (SLE) is complex autoimmune disease with heterogenous manifestations, unpredictable disease course and response to treatment. One of the critical needs in SLE management is the identification of reliable biomarkers that can aid in early diagnosis, accurate monitoring of disease activity, and assessment of treatment response.

AREAS COVERED

In the current review, we focus on the commonly affected organs (skin, kidney, and nervous system) in SLE to summarize the emerging biomarkers that show promise in disease diagnosis, monitoring and treatment response assessment. The subtitles within each organ domain were determined based on the most relevant and promising biomarkers for that specific organ damage.

EXPERT OPINION

Biomarkers have the potential to significantly benefit the management of SLE by aiding in diagnosis, disease activity monitoring, prognosis, and treatment response assessment. However, despite decades of research, none has been validated and implemented for routine clinical use. Novel biomarkers could lead to the development of precision medicine for SLE, guide personalized treatment, and improve patient outcomes. Challenges in biomarker research in SLE include defining clear and clinically relevant questions, accounting for the heterogeneity of SLE, and confirming initial findings in larger, multi-center, multi-ethnic, independent cohorts that reflect real-world clinical scenarios.

Novel CSF biomarkers for diagnosis and integrated analysis of neuropsychiatric systemic lupus erythematosus: based on antibody profiling

BACKGROUND

Neuropsychiatric systemic lupus erythematosus (NPSLE), with various morbidities and multiple manifestations in the central nervous system, remains a limited standard for diagnosis. Our study was to discover novel biomarkers for improving the diagnostic efficiency for NPSLE.

METHODS

We performed a quantitative planar protein antibody microarray to screen 1000 proteins in cerebrospinal fluid from controls, systemic lupus erythematosus (SLE, non-NPSLE) patients, and NPSLE patients. Differentially expressed proteins (DEPs) as candidate biomarkers were developed into a custom multiplexed protein antibody array for further validation in an independent larger cohort. Subsequently, we used least absolute shrinkage and selection operator regression (LASSO) analysis and multivariable logistic regression analysis for optimizing feature selection and constructing a diagnostic model. A receiver operating characteristic curve (ROC) was generated to assess the effectiveness of the models.

RESULTS

The expression of 29 proteins in CSF was significantly altered in the comparison of the three groups. We selected 17 proteins as candidate biomarkers in accordance with protein interaction analysis. In the larger cohort, we identified 5 DEPs as biomarkers for NPSLE, including TCN2, CST6, KLK5, L-selectin, and Trappin-2. The diagnostic model included 3 hub proteins (CST6, TCN2, KLK5) and was best at discriminating NPSLE from SLE patients. These CSF biomarkers were also highly associated with disease activity. In addition, there were 6 molecules with remarkable changes in NPSLE CSF and hippocampus, which indicated the consistency of the environment in the brain and the promising molecular targets in the pathogenesis of NPSLE.

CONCLUSIONS

The dual-chips screening strategy demonstrated KLK5, L-selectin, Trappin-2, TCN2, and CST6 as CSF biomarkers for diagnosing NPSLE.

The conundrum of neuropsychiatric systemic lupus erythematosus: Current and novel approaches to diagnosis

Recognising neuropsychiatric involvement by systemic lupus erythematosus (SLE) is of growing importance, however many barriers to this exist at multiple levels of our currently available diagnostic algorithms that may ultimately delay its diagnosis and subsequent treatment. The heterogeneous and non-specific clinical syndromes, serological and cerebrospinal fluid (CSF) markers and neuroimaging findings that often do not mirror disease activity, highlight important research gaps in the diagnosis of neuropsychiatric SLE (NPSLE). Formal neuropsychological assessments or the more accessible screening metrics may also help improve objective recognition of cognitive or mood disorders. Novel serum and CSF markers, including autoantibodies, cytokines and chemokines have also shown increasing utility as part of diagnosis and monitoring, as well as in distinguishing NPSLE from SLE patients without SLE-related neuropsychiatric manifestations. Novel neuroimaging studies also expand upon our existing strategy by quantifying parameters that indicate microarchitectural integrity or provide an assessment of neuronal function. Some of these novel markers have shown associations with specific neuropsychiatric syndromes, suggesting that future research move away from considering NPSLE as a single entity but rather into its individually recognized neuropsychiatric manifestations. Nevertheless, it is likely that a composite panel of these investigations will be needed to better address the gaps impeding recognition of neuropsychiatric involvement by SLE.

Progress in the Pathogenesis and Treatment of Neuropsychiatric Systemic Lupus Erythematosus

Neuropsychiatric systemic lupus erythematosus (NPSLE) has a broad spectrum of subtypes with diverse severities and prognoses. Ischemic and inflammatory mechanisms, including autoantibodies and cytokine-mediated pathological processes, are key components of the pathogenesis of NPSLE. Additional brain-intrinsic elements (such as the brain barrier and resident microglia) are also important facilitators of NPSLE. An improving understanding of NPSLE may provide further options for managing this disease. The attenuation of neuropsychiatric disease in mouse models demonstrates the potential for novel targeted therapies. Conventional therapeutic algorithms include symptomatic, anti-thrombotic, and immunosuppressive agents that are only supported by observational cohort studies, therefore performing controlled clinical trials to guide further management is essential and urgent. In this review, we aimed to present the latest pathogenetic mechanisms of NPSLE and discuss the progress in its management.

Insights into the role of neutrophils in neuropsychiatric systemic lupus erythematosus: Current understanding and future directions

Central nervous system (CNS) involvement of systemic lupus erythematosus (SLE), termed neuropsychiatric SLE (NPSLE), is a major and debilitating manifestation of the disease. While patients with SLE mostly complain of common neuropsychological symptoms such headache and mild mood disorders that may not even be technically attributed to SLE, many SLE patients present with life-threatening NPSLE syndromes such as cerebrovascular disease, seizures and psychosis that are equally challenging in terms of early diagnosis and therapy. While we are just beginning to unravel some mysteries behind the immunologic basis of NPSLE, advancements in the mechanistic understanding of the complex pathogenic processes of NPSLE have been emerging through recent murine and human studies. The pathogenic pathways implicated in NPSLE are multifarious and various immune effectors such as cell-mediated inflammation, autoantibodies and cytokines including type I interferons have been found to act in concert with the disruption of the blood-brain barrier (BBB) and other neurovascular interfaces. Beyond antimicrobial functions, neutrophils are emerging as decision-shapers during innate and adaptive immune responses. Activated neutrophils have been recognized to be involved in ischemic and infective processes in the CNS by releasing neutrophil extracellular traps (NETs), matrix metalloproteinase-9 and proinflammatory cytokines. In the context of NPSLE, these mechanisms contribute to BBB disruption, neuroinflammation and externalization of modified proteins on NETs that serve as autoantigens. Neutrophils that sediment within the peripheral blood mononuclear cell fraction after density centrifugation of blood are generally defined as low-density neutrophils (LDNs) or low-density granulocytes. LDNs are a proinflammatory subset of neutrophils that are increased with SLE disease activity and are primed to undergo NETosis and release cytokines such as interferon-α and tumor necrosis factor. This review discusses the immunopathogenesis of NPSLE with a focus on neutrophils as a core mediator of the disease and potential target for translational research in NPSLE.

Extensive Longitudinal Transverse Myelitis after Influenza A Virus Infection in a Patient with Systemic Lupus Erythematosus

Transverse myelitis (TM) is a rare complication seen in 1–2% of patients with systemic lupus erythematosus (SLE). Viral infections may cause TM in these patients by causing a dysregulation of their immune system. We report a 30-year-old woman with SLE who had influenza A and a few days later developed urinary retention, bilateral lower extremity paralysis, upper extremity weakness, and optic nerve and macular edema. Magnetic resonance imaging showed C4-T12 hyperintense lesions consistent with TM. She was treated with intravenous methylprednisolone 1 g daily for 3 days and then 6 cycles of monthly intravenous cyclophosphamide. This treatment was followed by oral prednisone. She had a remarkable clinical response. Visual acuity improved to her baseline, and muscle strength almost fully recovered. Clinicians should be aware that viral infections, including influenza, may induce TM. This case highlights the importance of early recognition and prompt treatment with immunosuppressive drugs in such cases.

Tissue resident cell processes determine organ damage in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects almost any organ. Multiple immunological abnormalities involving every domain of the immune system contribute to the expression of the disease. It is now recognized that elements of the immune system instigate processes in tissue resident cells which execute organ damage. Although correction of ongoing immune aberrations is important in the control of disease activity, targeting tissue specific injurious processes may prove desirable in limiting organ damage.

Neutrophil Dysregulation in the Pathogenesis of Systemic Lupus Erythematosus

The recent identifications of a subset of proinflammatory neutrophils, low-density granulocytes, and their ability to readily form neutrophil extracellular traps led to a resurgence of interest in neutrophil dysregulation in the pathogenesis of systemic lupus erythematosus (SLE). This article presents an overview on how neutrophil dysregulation modulates the innate and adaptive immune responses in SLE and their putative roles in disease pathogenesis. The therapeutic potential of targeting this pathogenic process in the treatment of SLE is also discussed.

Cognitive Dysfunction in Systemic Lupus Erythematosus: Immunopathology, Clinical Manifestations, Neuroimaging and Management

Cognitive dysfunction (CD) is a common yet often clinically subtle manifestation that considerably impacts the health-related quality of life in patients with systemic lupus erythaematosus (SLE). Given the inconsistencies in CD assessment and challenges in its attribution to SLE, the reported prevalence of CD differs widely, ranging from 3 to 88%. The clinical presentation of CD in SLE is non-specific and may manifest concurrently with overt neuropsychiatric illness such as psychosis or mood disorders or as isolated impairment of attention, working memory, executive dysfunction or processing speed. Despite the lack of standardized and sensitive neuropsychological tests and validated diagnostic biomarkers of CD in SLE, significant progress has been made in identifying pathogenic neural pathways and neuroimaging. Furthermore, several autoantibodies, cytokines, pro-inflammatory mediators and metabolic factors have been implicated in the pathogenesis of CD in SLE. Abrogation of the integrity of the blood-brain barrier (BBB) and ensuing autoantibody-mediated neurotoxicity, complement and microglial activation remains the widely accepted mechanism of SLE-related CD. Although several functional neuroimaging modalities have consistently demonstrated abnormalities that correlate with CD in SLE patients, a consensus remains to be reached as to their clinical utility in diagnosing CD. Given the multifactorial aetiology of CD, a multi-domain interventional approach that addresses the risk factors and disease mechanisms of CD in a concurrent fashion is the favourable therapeutic direction. While cognitive rehabilitation and exercise training remain important, specific pharmacological agents that target microglial activation and maintain the BBB integrity are potential candidates for the treatment of SLE-related CD.

The immunologic etiology of psychiatric manifestations in systemic lupus erythematosus: A narrative review on the role of the blood brain barrier, antibodies, cytokines and chemokines

INTRODUCTION

The aim of this narrative review is to provide an overview of the literature on the possible immunologic pathophysiology of psychiatric manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

A systematic search on PubMed was conducted. English studies with full text availability that investigated the correlation between blood-brain barrier (BBB) dysfunction, intrathecal synthesis of antibodies, antibodies, cytokines, chemokines, metalloproteinases, complement and psychiatric NPSLE manifestations in adults were included.

RESULTS

Both transient BBB-dysfunction with consequent access of antibodies to the cerebrospinal fluid (CSF) and intrathecal synthesis of antibodies could occur in psychiatric NPSLE. Anti-phospholipid antibodies, anti-NMDA antibodies and anti-ribosomal protein p antibodies seem to mediate concentration dependent neuronal dysfunction. Interferon-α may induce microglial engulfment of neurons, direct neuronal damage and production of cytokines and chemokines in psychiatric NPSLE. Several cytokines, chemokines and matrix metalloproteinase-9 may contribute to the pathophysiology of psychiatric NPSLE by attracting and activating Th1-cells and B-cells.

DISCUSSION

This potential pathophysiology may help understand NPSLE and may have implications for the diagnostic management and therapy of psychiatric NPSLE. However, the presented pathophysiological model is based on correlations between potential immunologic etiologies and psychiatric NPSLE that remain questionable. More research on this topic is necessary to further elucidate the pathophysiology of NPSLE.

Advances in the Potential Biomarkers of Epilepsy

Epilepsy is a group of chronic neurological disorders characterized by recurrent, spontaneous, and unpredictable seizures. It is one of the most common neurological disorders, affecting tens of millions of people worldwide. Comprehensive studies on epilepsy in recent decades have revealed the complexity of epileptogenesis, in which immunological processes, epigenetic modifications, and structural changes in neuronal tissues have been identified as playing a crucial role. This review discusses the recent advances in the biomarkers of epilepsy. We evaluate the possible molecular background underlying the clinical changes observed in recent studies, focusing on therapeutic investigations, and the evidence of their safety and efficacy in the human population. This article reviews the pathophysiology of epilepsy, including recent reports on the effects of oxidative stress and hypoxia, and focuses on specific biomarkers and their clinical implications, along with further perspectives in epilepsy research.

Review: Nervous System Disease in Systemic Lupus Erythematosus: Current Status and Future Directions

The American College of Rheumatology's case definitions for 19 neuropsychiatric syndromes in systemic lupus erythematosus (SLE) constitute a comprehensive classification of nervous system events in this disease. However, additional strategies are needed to determine whether a neuropsychiatric syndrome is attributable to SLE versus a competing comorbidity. Cognitive function is a clinical surrogate of overall brain health, with applications in both diagnosis and determination of clinical outcomes. Ischemic and inflammatory mechanisms are both key components of the immunopathogenesis of neuropsychiatric SLE (NPSLE), including abnormalities of the blood-brain barrier and autoantibody-mediated production of proinflammatory cytokines. Advances in neuroimaging provide a platform to assess novel disease mechanisms in a noninvasive way. The convergence of more rigorous clinical characterization, validation of biomarkers, and brain neuroimaging provides opportunities to determine the efficacy of novel targeted therapies in the treatment of NPSLE.

Identification of Levels of Serum Amyloid A and Apolipoprotein A1 in Serum Proteomic Analysis of Neuropsychiatric Systemic Lupus Erythematosus Patients

Neuropsychiatric Systemic Lupus Erythematosus (NPSLE) has multiple pathogenic mechanisms that cause diverse manifestations and whose diagnosis is challenging because of the absence of appropriate diagnostic tests. In the present study the application of proteomics using two-dimensional electrophoresis (2D) and mass spectrometry (MS) allowed the comparison of the protein profile of the serum low and high abundance protein fractions of NPSLE patients (NPSLE group) and SLE without neuropsychiatric syndromes (SLE group), Neuropsychiatric syndromes not associated with SLE (NPnoSLE groups), and healthy controls (CTRL group). The gels obtained were digitalized and analyzed with the PDQuest software. The statistical analysis of the spots was performed using the nonparametric Kruskal Wallis and Dunn's multiple comparison tests. Two spots showed significant differences and were identified by MS. Spot 4009 was significantly lower in NPSLE with regard to NPnoSLE (p= 0,004) and was identified as apolipoprotein A1 (APOA1) (score 809-1132). Spot 8001 was significantly higher in NPSLE regarding CTRL and NPnoSLE (p= 0,01 y 0,03, respectively) and was identified as serum amyloid A (SAA) (score 725-2488). The proinflammatory high density lipoproteins (HDL) have been described in SLE. In this HDL the decrease of APOA1 is followed by an increase in SAA. This altered level of both proteins may be related to the inflammatory state that is characteristic of an autoimmune disease like SLE, but this is not specific for NPSLE.

Regulation of Neuroinflammation: What Role for the Tumor Necrosis Factor-Like Weak Inducer of Apoptosis/Fn14 Pathway?

Observed in many central nervous system diseases, neuroinflammation (NI) proceeds from peripheral immune cell infiltration into the parenchyma, from cytokine secretion and from oxidative stress. Astrocytes and microglia also get activated and proliferate. NI manifestations and consequences depend on its context and on the acute or chronic aspect of the disease. The tumor necrosis factor-like weak inducer of apoptosis (TWEAK)/Fn14 pathway has been involved in chronic human inflammatory pathologies such as neurodegenerative, autoimmune, or malignant diseases. New data now describe its regulatory effects in tissues or fluids from patients with neurological diseases. In this mini-review, we aim to highlight the role of TWEAK/Fn14 in modulating NI in multiple sclerosis, neuropsychiatric systemic lupus erythematosus, stroke, or glioma. TWEAK/Fn14 can modulate NI by activating canonical and non-canonical nuclear factor-κB pathways but also by stimulating mitogen-activated protein kinase signaling. These downstream activations are associated with (i) inflammatory cytokine, chemokine and adhesion molecule expression or release, involved in NI propagation, (ii) matrix-metalloproteinase 9 secretion, implicated in blood–brain barrier disruption and tissue remodeling, (iii) astrogliosis and microgliosis, and (iv) migration of tumor cells in glioma. In addition, we report several animal and human studies pointing to TWEAK as an attractive therapeutic target.

Lupus brain fog: a biologic perspective on cognitive impairment, depression, and fatigue in systemic lupus erythematosus

Cognitive disturbances, mood disorders and fatigue are common in SLE patients with substantial adverse effects on function and quality of life. Attribution of these clinical findings to immune-mediated disturbances associated with SLE remains difficult and has compromised research efforts in these areas. Improved understanding of the role of the immune system in neurologic processes essential for cognition including synaptic plasticity, long term potentiation and adult neurogenesis suggests multiple potential mechanisms for altered central nervous system function associated with a chronic inflammatory illness such as SLE. This review will focus on the biology of cognition and neuroinflammation in normal circumstances and potential biologic mechanisms for cognitive impairment, depression and fatigue attributable to SLE.

The diagnosis and clinical management of the neuropsychiatric manifestations of lupus

Neuropsychiatric (NP) involvement in Systemic Lupus Erythematosus (SLE), can be a severe and troubling manifestation of the disease that heavily impacts patient's health, quality of life and disease outcome. It is one of the most complex expressions of SLE which can affect central, peripheral and autonomous nervous system. Complex interrelated pathogenetic mechanisms, including genetic factors, vasculopathy, vascular occlusion, neuroendocrine-immune imbalance, tissue and neuronal damage mediated by autoantibodies, inflammatory mediators, blood brain barrier dysfunction and direct neuronal cell death can be all involved. About NPSLE a number of issues are still matter of debate: from classification and burden of NPSLE to attribution and diagnosis. The role of neuroimaging and new methods of investigation still remain pivotal and rapidly evolving as well as is the increasing knowledge in the pathogenesis. Overall, two main pathogenetic pathways have been recognized yielding different clinical phenotypes: a predominant ischemic-vascular one involving large and small blood vessels, mediated by aPL, immune complexes and leuko-agglutination which it is manifested with more frequent focal NP clinical pictures and a predominantly inflammatory-neurotoxic one mediated by complement activation, increased permeability of the BBB, intrathecal migration of autoantibodies, local production of immune complexes and pro-inflammatory cytokines and other inflammatory mediators usually appearing as diffuse NP manifestations. In the attempt to depict a journey throughout NPSLE from diagnosis to a reasoned therapeutic approach, classification, epidemiology, attribution, risk factors, diagnostic challenges, neuroimaging techniques and pathogenesis will be considered in this narrative review based on the most relevant and recent published data.

Proposed response criteria for neurocognitive impairment in systemic lupus erythematosus clinical trials

The objective of this study was to identify reliable and valid instruments to measure cognitive impairment in systemic lupus erythematosus (SLE), and to define minimally important change of cognitive impairment in SLE for clinical trials. Neurocognitive measures used in randomized clinical trials in SLE were reviewed, and response criteria were developed using consensus expert opinion. The definition of cognitive impairment in the ACR nomenclature for neuropsychiatric lupus syndrome was adopted. Cognitive impairment is a deficit of 2.0 or more standard deviations (SD) below the mean, compared to normative data, in the key domains of attention, memory and psychomotor speed. Cognitive decline is defined as a deficit of 1.5—1.9 SD below the mean. Focal decline is defined if impairment exists in one or more measures within one domain, and multifocal decline if impairment exists on measures spanning two or more domains. The combination of ACR neuropsychological battery and the Cognitive Symptoms Inventory (CSI) is recommended to quantitate cognitive function. A clinically important response is defined as an improvement of ≥ 1.0 SD with an effect size of 1.0 in the key domains of the ACR neuropsychological testing, and an improvement of ≥ 1.0 SD with an effect size of 1.0 in functional performance of the CSI. Lupus (2007) 16, 418—425

Combined Effects of ACE and MMP-3 Polymorphisms On Migraine Development

Migraine is a primary headache disorder which involves both genetic and environmental components. Since angiotensin-converting enzyme (ACE) and matrix metalloproteinase (MMP) share the same homology, we investigated whether the MMP-3 and ACE I/D gene variants are involved in migraine risk and whether the ACE variant might act in combination with the MMP-3 genetic variant in patients with migraine. This is the first study to evaluate the association between MMP-3 and ACE polymorphisms, and migraine. Genotypes were determined by polymerase chain reaction. The frequencies of 5A5A genotypes of the MMP-3 and D allele of ACE were significantly elevated, but II genotypes of the ACE and 6A allele of MMP-3 significantly decreased in all patients. The combined DD/5A5A and ID/5A5A genotypes increased the risk of migraine. Individuals who were homozygous for the deletion (D) allele showed increased ACE activity. Subjects with the 5A5A genotype and/or D allele or with the combined DD/5A5A or ID/5A5A might be more susceptible to migraine development. In contrast, subjects with the II and/or 6A6A genotypes may be protected from migraine development. The greater activity of the 5A5A and DD genotypes might result in vascular reactivity that is more pronounced in migraine. Taken together, our data suggest that numerous genes may influence ACE activity. Discovery of new genes might better clarify the pathogenesis of migraine and open an avenue to therapeutic strategies against migraine.

Anti-NR2A/B Antibodies and Other Major Molecular Mechanisms in the Pathogenesis of Cognitive Dysfunction in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects approximately 1–45.3 per 100,000 people worldwide. Although deaths as a result of active and renal diseases have been substantially declining amongst SLE patients, disease involving the central nervous system (CNS), collectively termed neuropsychiatric systemic lupus erythematosus (NPSLE), remains one of the important causes of death in these patients. Cognitive dysfunction is one of the most common manifestations of NPSLE, which comprises deficits in information-processing speed, attention and executive function, in conjunction with preservation of speech. Albeit a prevalent manifestation of NPSLE, the pathogenetic mechanisms of cognitive dysfunction remain unclear. Recent advances in genetic studies, molecular techniques, neuropathology, neuroimaging and cognitive science have gleaned valuable insights into the pathophysiology of lupus-related cognitive dysfunction. In recent years, a role for autoantibodies, molecular and cellular mechanisms in cognitive dysfunction, has been emerging, challenging our previous concept of the brain as an immune privileged site. This review will focus on the potential pathogenic factors involved in NPSLE, including anti-N-methyl-d-aspartate receptor subunit NR2A/B (anti-NR2A/B) antibodies, matrix metalloproteinase-9, neutrophil extracellular traps and pro-inflammatory mediators. Better understanding of these mechanistic processes will enhance identification of new therapeutic modalities to halt the progression of cognitive decline in SLE patients.

Matrix metalloproteinase 9 polymorphisms and systemic lupus erythematosus: correlation with systemic inflammatory markers and oxidative stress

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple organs and is characterized by persistent systemic inflammation. Among the effects of inflammatory mediators, the induction of matrix metalloproteinases-2 and -9 (MMP-2 and MMP-9) and oxidative stress has been demonstrated to be important in the development of SLE. In this study, the possible association between MMP-9 and MMP-2 functional promoter polymorphism, stress, and inflammatory markers with development of severe cardiovascular disease (CVD), high blood pressure (HBP), and lupus nephropathy (LN) in SLE patients was investigated. The present case-control study consisted of 109 SLE patients with and without CVD, HBP and LN and 101 gender- and age-matched unrelated healthy controls from a population in western Iran. MMP-2 –G1575A and MMP-9 –C1562T polymorphisms were detected by PCR-RFLP, serum MMP-2 and MMP-9, neopterin, malondialdehyde (MDA) and lipid levels were determined by ELISA, HPLC and enzyme assay, respectively. We found that MMP-9 –C1562 T and MMP-2 –G1575A alleles act synergistically to increase the risk of SLE by 2.98 times ( p = 0.015). Findings of this study also demonstrated that there is a significant increase in the serum levels of MMP-2, neopterin and MDA and a significant decrease in serum level of MMP-9 in the presence of MMP-9-C1562 T and MMP-2 –G1575A alleles in SLE patients compared to controls. Further, SLE patients with MMP-9 (C/T + T/T) genotype had significantly higher serum concentrations of MMP-2, neopterin, MDA and LDL-C, but lower serum MMP-9 and HDL-C levels than corresponding members of the control group. MMP-9 (C/T + T/T) genotype increased risk of hypertension in SLE patients 2.71-fold. This study for the first time not only suggests that MMP-9 –C1562 T and MMP-2 –G1575A alleles synergistically increase the risk of SLE but also high serum levels of MDA, neopterin, and circulatory levels of MMP-2 and lower MMP-9 in SLE patients. This information may be important in the evaluation of SLE progression and in the elucidation of the mechanisms of the disease pathogenesis.

MMPs: a novel drug target for schizophrenia

INTRODUCTION

Schizophrenia, a multifactorial disorder, is associated with dopaminergic hyperactivity, dysregulated glutamatergic neurotransmission, neuroinflammation and extracellular matrix (ECM) disturbances. MMPs, a group of structurally related proteolytic enzymes, are responsible for remodeling of ECM that maintains synaptic functions and blood-brain barrier (BBB) patency. Overstimulation of MMPs by neuroinflammation triggers ECM abnormalities that directly or indirectly alter neuronal functions like synaptic plasticity and damage to BBB. MMP-mediated ECM abnormality plays a central role in the pathogenesis of schizophrenia.

AREAS COVERED

The current review discusses the mechanistic involvement of MMPs in the pathogenesis of schizophrenia and briefly gives an overview on the recent studies on various MMP modulators.

EXPERT OPINION

Overexpression of MMPs and imbalance between MMP versus tissue inhibitors of metalloproteinase are associated with various ECM disturbances in the schizophrenic brain. Therefore, MMPs can be projected as potential therapeutic target for treatment and/or prevention of positive, negative and cognitive symptoms of schizophrenia. From past decade, scientific community is focusing on broad spectrum MMP modulators as potential therapeutic moieties for prevention of plethora of neurological, cardiovascular and pulmonary diseases. In future, specific MMP modulators should be tailored to regulate ECM integrity and explored for their pharmacotherapeutic potential in schizophrenia.

Raised IL-2 and TNF-α concentrations are associated with postoperative delirium in patients undergoing coronary-artery bypass graft surgery

BACKGROUND

The knowledge base regarding the pathogenesis of postoperative delirium is limited. The primary aim of this study is to investigate whether increased levels of IL-2 and TNF-α are associated with delirium in patients who underwent coronary-artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB). The secondary aim is to establish whether any association between raised cytokine levels and delirium is related to surgical and anesthetic procedures or mediated by pre-existing conditions associated with raised cytokine levels, such as major depressive disorder (MDD), cognitive impairment, or aging.

METHODS

Patients were examined and screened for MDD and cognitive impairment one day preoperatively, using the Mini International Neuropsychiatric Interview and The Montreal Cognitive Assessment and Trail Making Test Part B. Blood samples were collected postoperatively for cytokine levels.

RESULTS

Postoperative delirium screening was found positive in 36% (41 of 113) of patients. A multivariate logistic regression revealed that an increased concentration of pro-inflammatory cytokines is associated with delirium, and related to advancing age, preoperative cognitive decline of participants, and duration of CPB. According to receiver operating characteristic analysis, the most optimal cut-off for IL-2 and TNF-α concentrations in predicting the development of delirium were 907.5 U/ml and 10.95 pg/ml, respectively.

CONCLUSIONS

The present study suggests that raised postoperative cytokine concentrations are associated with delirium after CABG surgery. Postoperative monitoring of pro-inflammatory markers combined with regular surveillance may be helpful in the early detection of postoperative delirium in this patient group.

Neuropsychiatric Lupus, the Blood Brain Barrier, and the TWEAK/Fn14 Pathway

Patients with systemic lupus erythematosus (SLE) can experience acute neurological events such as seizures, cerebrovascular accidents, and delirium, psychiatric conditions including depression, anxiety, and psychosis, as well as memory loss and general cognitive decline. Neuropsychiatric SLE (NPSLE) occurs in between 30 and 40% of SLE patients, can constitute the initial patient presentation, and may occur outside the greater context of an SLE flare. Current efforts to elucidate the mechanistic underpinnings of NPSLE are focused on several different and potentially complementary pathways, including thrombosis, brain autoreactive antibodies, and complement deposition. Furthermore, significant effort is dedicated to understanding the contribution of neuroinflammation induced by TNF, IL-1, IL-6, and IFN-γ. More recent studies have pointed to a possible role for the TNF family ligand TWEAK in the pathogenesis of neuropsychiatric disease in human lupus patients, and in a murine model of this disease. The blood brain barrier (BBB) consists of tight junctions between endothelial cells (ECs) and astrocytic projections which regulate paracellular and transcellular flow into the central nervous system (CNS), respectively. Given the privileged environment of the CNS, an important question is whether and how the integrity of the BBB is compromised in NPSLE, and its potential pathogenic role. Evidence of BBB violation in NPSLE includes changes in the albumin quotient (Q_alb) between plasma and cerebrospinal fluid, activation of brain ECs, and magnetic resonance imaging. This review summarizes the evidence implicating BBB damage as an important component in NPSLE development, occurring via damage to barrier integrity by environmental triggers such as infection and stress; cerebrovascular ischemia as result of a generally prothrombotic state; and immune mediated EC activation, mediated by antibodies and/or inflammatory cytokines. Additionally, new evidence supporting the role of TWEAK/Fn14 signaling in compromising the integrity of the BBB in lupus will be presented.

Neuropsychiatric systemic lupus erythematosus

Neuropsychiatric systemic lupus erythematosus (NPSLE) is the least understood, yet perhaps the most prevalent manifestation of lupus. The pathogenesis of NPSLE is multifactorial and involves various inflammatory cytokines, autoantibodies, and immune complexes resulting in vasculopathic, cytotoxic and autoantibody-mediated neuronal injury. The management of NPSLE is multimodal and has not been subjected to rigorous study. Different treatment regimens include nonsteroidal anti-inflammatory drugs, anticoagulation, and immunosuppressives such as cyclophosphamide, azathioprine, mycophenolate mofetil, and methotrexate. For refractory NPSLE, intravenous immunoglobulin (IVIG), plasmapheresis, and rituximab have been used. Adjunctive symptomatic treatment complements these therapies by targeting mood disorders, psychosis, cognitive impairment, seizures or headaches. Several new biological agents are being tested including Belimumab, a human monoclonal antibody that targets B lymphocyte stimulator. This review focuses on the pathophysiology, treatment, and new potential therapies for neuropsychiatric manifestations of systemic lupus erythematosus.

Why dapsone stops seizures and may stop neutrophils' delivery of VEGF to glioblastoma

Lopez-Gomez et al. recently published remarkable but mechanistically unexplained empirical evidence that the old antibiotic dapsone has antiepileptic activity. We addressed the question "Why should a sulfone antibiotic reduce seizures?". We report here our conclusions based on data from past studies that seizures are associated with elevated interleukin-8 (IL-8) and that dapsone inhibits IL-8 release and function in several different clinical and experimental contexts. Diverse CNS insults cause an increase in CNS IL-8. Thus, the pro-inflammatory environment generated by increase IL-8 leads to a lower seizure threshold. Together this evidence indicates dapsone exerts anti-seizure activity by diminishing IL-8 signalling. Since IL-8 is clearly upregulated in glioblastoma and contributes to the florid angiogenesis of that disease, and since interference with IL-8 function has been shown to inhibit glioblastoma invasion and growth in several experimental models, and dapsone has been repeatedly been shown to clinically inhibit IL-8 function when used to treat human neutrophilic dermatoses, we believe that dapsone thereby reduces seizures by countering IL-8 function and may similarly retard glioblastoma growth by such anti-IL-8 function.

Matrix metalloproteinases

Remodeling of extracellular matrix is crucial for many physiological (cell migration, proliferation, growth, and development) and pathological (remodeling of heart, carcinogenesis, metastasis, etc.) events. Thus, the interaction between cells and extracellular matrix plays a key role in normal development and differentiation of organism and many pathological states as well. Changes in extracellular matrix are regulated by a system of proteolytic enzymes that are responsible for proteolysis of huge quantity of extracellular matrix components. Matrix metalloproteinases (MMPs) represent the main group of regulating proteases in ECM. Ability of matrix metalloproteinases to modify the structural integrity of tissues is essential for certain aspects of normal physiology and pathology. The ability to process molecules such as growth factors, receptors, adhesion molecules, other proteinases, and proteinase inhibitors makes MMPs potent controllers of physiological and pathological events in the cell microenvironment. Overactivation of MMPs has been implicated in numerous disease states.

Glutamate receptor biology and its clinical significance in neuropsychiatric systemic lupus erythematosus

The recent appreciation that a subset of anti-DNA antibodies cross-reacts with the N-methyl-d-aspartate receptor encourages a renewed examination of antibrain reactivity in systemic lupus erythematosus (SLE) autoantibodies. Moreover, investigations of their autospecificity present a paradigm for studies of antibrain reactivity and show that (1) serum antibodies access brain tissue only after a compromise of blood-brain barrier integrity, (2) the same antibodies have differential effects on brain function depending on the region of brain exposed to the antibodies, and (3) insults to the blood-brain barrier are regional rather than diffuse. These studies suggest that an anatomic classification scheme for neuropsychiatric SLE may facilitate research on etiopathogenesis and the design of clinical trials.

Pathogenesis, diagnosis and management of neuropsychiatric SLE manifestations

Neuropsychiatric events are common in patients with systemic lupus erythematosus (SLE), but less than one-third of these events can be directly attributed to SLE. Increased generalized SLE disease activity or damage, previous or concurrent major neuropsychiatric SLE (NPSLE) events, and persistently positive moderate-to-high antiphospholipid antibody titers are established risk factors, and their presence could facilitate proper attribution to the disease itself. Diagnostic evaluation is guided by the presenting manifestation; MRI is used to visualize brain or spinal pathologies. For neuropsychiatric events believed to reflect an immune or inflammatory process, or when these events occur in the context of active generalized disease, evidence (primarily from uncontrolled studies) supports the use of glucocorticoids alone or in combination with immunosuppressive therapy. Antiplatelet and/or anticoagulation therapy is recommended for NPSLE manifestations related to antiphospholipid antibodies, especially for thrombotic cerebrovascular disease. For the future, we anticipate that novel biomarkers and advanced neuroimaging tests will better define the underlying pathologic mechanisms of SLE-related neuropsychiatric disease, and help guide therapeutic decisions.

TWEAK as a target for therapy in systemic lupus erythematosus

Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is a recently identified proinflammatory cytokine of the TNF superfamily. Through activation of the fibroblast growth factor-inducible 14 (Fn14) receptor, TWEAK regulates cell proliferation, cell death and inflammation. The available evidences have indicated that TWEAK might be a target for therapeutic intervention in renal, vascular injury and neuropathy. Since renal, vascular and neuropsychiatric complications are frequently encountered in systemic lupus erythematosus (SLE)--a systemic autoimmune disease, TWEAK-Fn14 pathway may be implicated in the pathogenesis of SLE. In this review, we will discuss the TWEAK-Fn14 pathway and the therapeutic potential of modulating this pathway in SLE.

Intrathecal cytokine and chemokine profiling in neuropsychiatric lupus or lupus complicated with central nervous system infection

The aims of this study are to investigate the cytokine, chemokine and adhesion molecule profiles in cerebrospinal fluid from patients with neuropsychiatric systemic lupus erythematosus and systemic lupus erythematosus with central nervous system infection. Experimental sets were established which included 108 patients and 132 cerebrospinal fluid samples. The patients were grouped as neuropsychiatric systemic lupus erythematosus (n = 54), systemic lupus erythematosus with central nervous system infection (n = 16), systemic lupus erythematosus controls (n=20), and non-inflammatory neurological disease (n=18). The dynamic changes of 21 patients in the neuropsychiatric systemic lupus erythematosus group before and after induction therapy were further analyzed. IL-1β, IL-4, IL-6, IL-8, IL-10, IL-12, IL-17, TNFα, IFNγ, IP-10, MCP-1, RANTES, VCAM-1, and P-selectin were measured in cerebrospinal fluid samples by using a fluorescent bead-based assay. Cerebrospinal fluid levels of IL-8, MCP-1, P-selectin and VCAM-1 were significantly increased in neuropsychiatric systemic lupus erythematosus compared with systemic lupus erythematosus controls. IL-6, IL-17, IL-8 and VCAM-1 were higher in systemic lupus erythematosus with central nervous system infection than in systemic lupus erythematosus controls. Among systemic lupus erythematosus with central nervous system infection, the IL-6, IL-17, IL-8 and IP-10 levels were higher than those in neuropsychiatric systemic lupus erythematosus. After sufficient induction therapy, IL-8, MCP-1, P-selectin, VCAM-1 and IL-6 in patients with neuropsychiatric systemic lupus erythematosus decreased significantly. Levels of all molecules tested in non-inflammatory central nervous system disease were not different from those of systemic lupus erythematosus controls. From our data, the intrathecal cytokine/chemokine profile is different among patients with neuropsychiatric systemic lupus erythematosus, systemic lupus erythematosus complicated with central nervous system infection and systemic lupus erythematosus controls. IL-8, MCP-1, VCAM-1, P-selectin and IL-6 in cerebrospinal fluid are effective parameters to monitor neuropsychiatric systemic lupus erythematosus disease activity and response to treatment. Significantly elevated IL-17, IL-6, and to a lesser extent, IL-8, favors central nervous system infection in systemic lupus erythematosus. Lupus (2010) 19, 689—695.

Pathogenesis of neuropsychiatric systemic lupus erythematosus and potential biomarkers

Systemic lupus erythematosus is a chronic, multisystemic, autoimmune disease that may involve the central, peripheral, and autonomic nervous systems and can present with a wide variety of neurological and psychiatric manifestations. In this article, we review the recent literature pertaining to the pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE). We searched the PUBMED database with no chronological constraints using the following terms: "neuropsychiatric systemic lupus erythematosus" cross-referenced with the terms "pathogenesis" and "biomarkers" for full-text articles in English. The etiology of NPSLE is as yet unknown, though numerous autoantibodies and cytokines have been suggested as possible mediators. Of the numerous autoantibodies and biomarkers examined, anti-phospholipid, anti-ribosomal P, anti-neuronal, anti-glial fibrillary acidic protein (GFAP), anti-endothelial cell, anti-N-methyl-D: -aspartate (NMDA), microtubule-associated protein 2 (MAP-2), and matrix metalloproteinase-9 (MMP-9) appear to be elevated in patients with NPSLE. Cytokines that may be involved in the pathology of NPSLE include interleukin (IL)-2, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-alpha, and interferons (IFN)-alpha and -gamma. With continued advances in immunological research, new insights into the pathophysiologic mechanisms of NPSLE may lead to the development of biomarkers and new treatment strategies.

Accuracy of cerebrospinal fluid IL-6 testing for diagnosis of lupus psychosis. A multicenter retrospective study

Psychiatric manifestations are relatively common in systemic lupus erythematosus (SLE) patients. Since there are factors causing psychiatric manifestations other than SLE, the diagnosis of lupus psychosis (LP) is often difficult. Previous studies disclosed that cerebrospinal fluid (CSF) IL-6 was elevated in SLE patients with neuropsychiatric manifestation. The current studies were therefore designed to examine the efficacy of CSF IL-6 in diagnosis of LP. Multicenter retrospective study was performed with 45 SLE patients who showed psychiatric manifestations between 1993 and 2000. The diagnosis of LP and psychosis due to causes other than SLE (non-LP) was confirmed by retrospective review of the clinical records. Thirty-two of the 45 patients were reconfirmed as LP in the retrospective study. Receiver operating characteristic curve analysis revealed that the sensitivity and specificity of CSF IL-6 for diagnosis of LP were 87.5% and 92.3%, respectively, at the cut-off value of 4.3 pg/ml. These results indicate that CSF IL-6 might be an effective measure in diagnosing LP, although exclusion of infectious meningoencephalitis and cerebrovascular accident is necessary.

Do schizophrenia and bipolar disorders share a common disease susceptibility variant at the MMP3 gene?

There is growing evidence of partial etiological overlap between schizophrenia (SZ) and bipolar I disorder (BD-I) from linkage analysis, genetic epidemiology and molecular genetics studies. SZ and BD-I are neurodevelopmental disorders with genetic and environmental etiologies. Recent studies have demonstrated that matrix metalloproteinase 3 (MMP3) is a key event in associative memory formation, learning and synaptic plasticity, which are important in psychiatric disorders. In the light of these findings, we analyzed the genetic variations in the MMP3-1171 5A/6A in patients with SZ, patients with BD-I and healthy controls. To the best of our knowledge, this is the first study to report an association of variation in gene encoding MMP3 with SZ. Our study group consisted of 111 unrelated patients with SZ, 141 unrelated patients with BD-I, and 121 unrelated healthy controls. The frequencies of 6A6A genotype and 6A allele distributions of MMP3 in patients with SZ were significantly decreased when compared with controls. In contrast, in patients with SZ, the distributions of 5A5A genotype and 5A allele of MMP3 gene were significantly increased as compared with healthy controls. When the frequencies of genotypes or alleles in schizophrenic patients and bipolar patients were compared, 6A6A genotype and 6A allele in patients with BD-I were significantly higher than patients with SZ. In contrast, 5A5A genotype and 5A allele distributions of MMP3 gene were significantly frequent in patients with SZ. On the other hand, no significant differences were found in the allele or genotype distribution in patients with BD-I compared with controls. In conclusion, our data have supported the hypothesis that there is a possible relationship between -1171 5A/6A polymorphism of MMP3 gene and SZ. A larger sample group is needed to confirm the potential role of this gene in the pathophysiology of psychiatric disorders.

Glomerular matrix metalloproteinases and their regulators in the pathogenesis of lupus nephritis

Lupus nephritis is a major contributor to morbidity and mortality in systemic lupus erythematosus, but little is known about the pathogenic processes that underlie the progressive decay in renal function. A common finding in lupus nephritis is thickening of glomerular basement membranes associated with immune complex deposition. It has been speculated that alterations in the synthesis or degradation of membrane components might contribute to such changes, and thereby to initiation and progression of nephritis through facilitation of immune complex deposition. Matrix metalloproteinases (MMPs) are enzymes that are intimately involved in the turnover of major glomerular basement membrane constituents, including collagen IV and laminins. Alterations in the expression and activity of MMPs have been described in a number of renal diseases, suggesting their relevance to the pathogenesis of various glomerulopathies. The same is true for their natural inhibitors, the tissue inhibitor of metalloproteinase family. Recent data from our group have identified an increase in proteolytic activity within the glomerulus coinciding with the development of proteinuria in the mouse model of systemic lupus erythematosus. (NXB x NZW)F1 Here we review current understanding of MMP/tissue inhibitor of metalloproteinase function within the kidney, and discuss their possible involvement in the development and progression of lupus nephritis.

Raised intrathecal levels of APRIL and BAFF in patients with systemic lupus erythematosus: relationship to neuropsychiatric symptoms

Introduction

The tumour necrosis factor (TNF) family ligands BAFF (B-cell activating factor of TNF family) and APRIL (a proliferation-inducing ligand) are essential for B-cell survival and function. Elevated serum levels of BAFF and APRIL have been reported earlier in patients with systemic lupus erythematosus (SLE). Since autoantibody formation in the central nervous system (CNS) is a distinct feature of neuropsychiatric SLE (NPSLE), we have investigated whether NPSLE is associated with an enhanced intrathecal production of APRIL and BAFF.

Methods

Levels of BAFF and APRIL in cerebrospinal fluid (CSF) and serum from healthy controls, SLE patients without CNS involvement, and patients with NPSLE were determined by enzyme-linked immunosorbent assay. Interleukin-6 (IL-6) levels were determined by an IL-6-specific bioassay.

Results

SLE patients had levels of APRIL in CSF that were more than 20-fold higher and levels of BAFF in CSF that were more than 200-fold higher than those of healthy controls. Separate analyses of SLE patients with and without CNS involvement revealed that NPSLE patients had enhanced levels of APRIL in CSF. BAFF and APRIL were likely produced locally in the CNS as CSF and serum levels did not correlate. Moreover, CSF levels of APRIL correlated with BAFF but not with IL-6, suggesting that APRIL and BAFF in the CNS are regulated together but that they are produced independently of IL-6.

Conclusion

To our knowledge this is the first study to show elevated levels of BAFF and APRIL in CSF of SLE patients. APRIL was augmented in NPSLE patients compared with SLE patients without CNS involvement. APRIL and BAFF antagonists breeching the blood-brain barrier therefore could have beneficial effects on SLE patients, in particular patients with NPSLE.