Behavioral and cognitive deficits occur only after prolonged exposure of mice to antiphospholipid antibodies

Antiphospholipid syndrome, antiphospholipid antibodies, and stroke

Antiphospholipid syndrome (APS) is a prothrombotic autoimmune disease with heterogeneous clinicopathological manifestations and is a well-established cause of acute ischemic stroke (AIS) and transient ischemic attack (TIA), particularly in younger patients. There is growing recognition of a wider spectrum of APS-associated cerebrovascular lesions, including white matter hyperintensities, cortical atrophy, and infarcts, which may have clinically important neurocognitive sequalae. Diagnosis of APS-associated AIS/TIA requires expert review of clinical and laboratory information. Management poses challenges, given the potential for substantial morbidity and recurrent thrombosis, additional risk conferred by conventional cardiovascular risk factors, and limited evidence base regarding optimal antithrombotic therapy for secondary prevention. In this review, we summarize key features of APS-associated cerebrovascular disorders, with focus on clinical and laboratory aspects of diagnostic evaluation. The current status of prognostic markers is considered. We review the evidence base for antithrombotic treatment in APS-associated stroke and discuss uncertainties, including the optimal intensity of anticoagulation and efficacy of direct oral anticoagulants. Clinical practice recommendations are provided, covering antithrombotic treatment, supportive management, and options for anticoagulant-refractory cases, and we highlight the benefits of adopting a considered, multidisciplinary team approach.

LPS-Induced Coagulation and Neuronal Damage in a Mice Model Is Attenuated by Enoxaparin

Background. Due to the interactions between neuroinflammation and coagulation, the neural effects of lipopolysaccharide (LPS)-induced inflammation (1 mg/kg, intraperitoneal (IP), n = 20) and treatment with the anti-thrombotic enoxaparin (1 mg/kg, IP, 15 min, and 12 h following LPS, n = 20) were studied in C57BL/6J mice. Methods. One week after LPS injection, sensory, motor, and cognitive functions were assessed by a hot plate, rotarod, open field test (OFT), and Y-maze. Thrombin activity was measured with a fluorometric assay; hippocampal mRNA expression of coagulation and inflammation factors were measured by real-time-PCR; and serum neurofilament-light-chain (NfL), and tumor necrosis factor-α (TNF-α) were measured by a single-molecule array (Simoa) assay. Results. Reduced crossing center frequency was observed in both LPS groups in the OFT (p = 0.02), along with a minor motor deficit between controls and LPS indicated by the rotarod (p = 0.057). Increased hippocampal thrombin activity (p = 0.038) and protease-activated receptor 1 (PAR1) mRNA (p = 0.01) were measured in LPS compared to controls, but not in enoxaparin LPS-treated mice (p = 0.4, p = 0.9, respectively). Serum NfL and TNF-α levels were elevated in LPS mice (p < 0.05) and normalized by enoxaparin treatment. Conclusions. These results indicate that inflammation, coagulation, neuronal damage, and behavior are linked and may regulate each other, suggesting another pharmacological mechanism for intervention in neuroinflammation.

Neurological and Neuropsychiatric Manifestations of Antiphospholipid-Antibody Syndrome (APS)

Antiphospholipid antibody syndrome (APS) is an autoimmune disorder mediated by the presence of a group of autoantibodies, specifically the anticardiolipin antibody (aCL), the beta-2 glycoprotein I (β2GPI), and the lupus anticoagulant (LA). Patients diagnosed with antiphospholipid antibody syndrome (APS) present with many symptoms, the most common being the consequence of thrombotic events that can be catastrophic and lead to mild to severe residual disabilities over a significant amount of time and can impair the quality of life. These events are often present in the younger population. Many times, these thrombotic events are heralded by a spectrum of psychiatric symptoms, which when worked up in the right direction may hint toward an oncoming thrombotic event and may potentially prevent those events by prompting primary prophylaxis treatment by the treating physician. In this review, we aim to comprehensively put forth the many neurological and neuropsychiatric manifestations of APS, their pathology, and management.

Teriflunomide normalizes anti-anxiety effect in anti-ANXA2 APS mice model teriflunomide in anti-ANXA2 mice model

Antiphospholipid syndrome (APS) affects the brain by both hypercoagulation and immunological mechanisms. APS is characterized by several autoantibodies binding to a thrombolytic complex including beta-2-glycoprotein I (β2-GPI) and annexin A2 (ANXA2). Teriflunomide, an oral drug for the treatment of multiple sclerosis (MS), has a cytostatic effect on B cells and is therefore a potential antibody-targeting treatment for APS. In this study, we assessed the effect of teriflunomide in two APS mouse models by inducing autoantibody formation against β2-GPI and ANXA2 in female BALB/c mice. The ANXA2 model displayed a behavioral change suggesting an anti-anxiety effect in open field and forced swim tests, early in the course of the disease. This effect was normalized following teriflunomide treatment. Conversely, behavioral tests done later during the study demonstrated depression-like behavior in the ANXA2 model. No behavioral changes were seen in the β2-GPI model. Total brain IgG levels were significantly elevated in the ANXA2 model but not in the teriflunomide treated group. No such change was noted in the brains of the β2-GPI model. High levels of serum autoantibodies were induced in both models, and their levels were not lowered by teriflunomide treatment. Teriflunomide ameliorated behavioral changes in mice immunized with ANXA2 without a concomitant change in serum antibody levels. These findings are compatible with the effect of teriflunomide on neuroinflammation.Teriflunomide ameliorated behavioral and brain IgG levels in mice immunized with ANXA2 without a concomitant change in serum antibody levels. These findings are compatible with an effect of teriflunomide on the IgG permeability to the brain and neuroinflammation.

Neurocoagulation from a Mechanistic Point of View in the Central Nervous System

Coagulation mechanisms are critical for maintaining homeostasis in the central nervous system (CNS). Thrombin, an important player of the coagulation cascade, activates protease activator receptors (PARs), members of the G-protein coupled receptor family. PAR1 is located on neurons and glia. Following thrombin activation, PAR1 signals through the extracellular signal-regulated kinase pathway, causing alterations in neuronal glutamate release and astrocytic morphological changes. Similarly, the anticoagulation factor activated protein C (aPC) can cleave PAR1, following interaction with the endothelial protein C receptor. Both thrombin and aPC are expressed on endothelial cells and pericytes in the blood-brain barrier (BBB). Thrombin-induced PAR1 activation increases cytosolic Ca²⁺ concentration in brain vessels, resulting in nitric oxide release and increasing F-actin stress fibers, damaging BBB integrity. aPC also induces PAR1 activation and preserves BBB vascular integrity via coupling to sphingosine 1 phosphate receptors. Thrombin-induced PAR1 overactivation and BBB disruption are evident in CNS pathologies. During epileptic seizures, BBB disruption promotes thrombin penetration. Thrombin induces PAR1 activation and potentiates N-methyl-D-aspartate receptors, inducing glutamate-mediated hyperexcitability. Specific PAR1 inhibition decreases status epilepticus severity in vivo. In stroke, the elevation of brain thrombin levels further compromises BBB integrity, with direct parenchymal damage, while systemic factor Xa inhibition improves neurological outcomes. In multiple sclerosis (MS), brain thrombin inhibitory capacity correlates with clinical presentation. Both thrombin inhibition by hirudin and the use of recombinant aPC improve disease severity in an MS animal model. This review presents the mechanisms underlying the effects of coagulation on the physiology and pathophysiology of the CNS.

Neuropsychiatric Manifestations of Antiphospholipid Syndrome—A Narrative Review

Antiphospholipid syndrome (APS) is a common autoimmune pro-thrombotic condition characterised by thrombosis and pregnancy morbidity. There are a broad range of neuropsychiatric manifestations associated with APS, from focal symptoms to more global dysfunction. Patients commonly present with transient ischaemic attacks and ischaemic strokes, with identifiable lesions on brain imaging. However, the underlying pathogenesis remains uncertain in other manifestations, such as cognitive dysfunction, seizures, headache and chorea. The aim is to provide a comprehensive review of the various neuropsychiatric manifestations associated with APS. A detailed literature search was applied to PubMed, including citations from 1983 to December 2021.

Cognitive Impairment in SLE: Mechanisms and Therapeutic Approaches

A wide range of patients with systemic lupus erythematosus (SLE) suffer from cognitive dysfunction (CD) which severely impacts their quality of life. However, CD remains underdiagnosed and poorly understood. Here, we discuss current findings in patients and in animal models. Strong evidence suggests that CD pathogenesis involves known mechanisms of tissue injury in SLE. These mechanisms recruit brain resident cells, in particular microglia, into the pathological process. While systemic immune activation is critical to central nervous system injury, the current focus of therapy is the microglial cell and not the systemic immune perturbation. Further studies are critical to examine additional potential therapeutic targets and more specific treatments based on the cause and progress of the disease.

Antiphospholipid Syndrome and the Neurologist: From Pathogenesis to Therapy

Antiphospholipid syndrome (APS) is an autoimmune antibody-mediated condition characterized by thrombotic events and/or pregnancy morbidity in association with persistent positivity to antiphospholipid antibodies (aPL). The nervous system is frequently affected, as intracranial vessels are the most frequent site of arterial pathology. Over the course of years, many other neurological conditions not included in the diagnostic criteria, have been associated with APS. The pathogenic mechanisms behind the syndrome are complex and not fully elucidated. aPL enhance thrombosis, interfering with different pathways. Nevertheless, ischemic injury is not always sufficient to explain clinical features of the syndrome and immune-mediated damage has been advocated. This may be particularly relevant in the context of neurological complications. The reason why only a subgroup of patients develop non-criteria nervous system disorders and what determines the clinical phenotype are questions that remain open. The double nature, thrombotic and immunologic, of APS is also reflected by therapeutic strategies. In this review we summarize known neurological manifestations of APS, revisiting pathogenesis and current treatment options.

Decreased hippocampal cell proliferation in mice with experimental antiphospholipid syndrome

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by the presence of antiphospholipid antibodies, which may trigger vascular thrombosis with consecutive infarcts. However, cognitive dysfunctions representing one of the most commonest neuropsychiatric symptoms are frequently present despite the absence of any ischemic brain lesions. Data on the structural and functional basis of the neuropsychiatric symptoms are sparse. To examine the effect of APS on hippocampal neurogenesis and on white matter, we induced experimental APS (eAPS) in adult female Balb/C mice by immunization with β2-glycoprotein 1. To investigate cell proliferation in the dentate gyrus granular cell layer (DG GCL), eAPS and control mice (n = 5, each) were injected with 5-bromo-2'-deoxyuridine (BrdU) once a day for 10 subsequent days. Sixteen weeks after immunization, eAPS resulted in a significant reduction of BrdU-positive cells in the DG GCL compared to control animals. However, double staining with doublecortin and NeuN revealed a largely preserved neurogenesis. Ultrastructural analysis of corpus callosum (CC) axons in eAPS (n = 6) and control mice (n = 7) revealed no significant changes in CC axon diameter or g-ratio. In conclusion, decreased cellular proliferation in the hippocampus of eAPS mice indicates a limited regenerative potential and may represent one neuropathological substrate of cognitive changes in APS while evidence for alterations of white matter integrity is lacking.

Cross-reactivity between annexin A2 and Beta-2-glycoprotein I in animal models of antiphospholipid syndrome

Antiphospholipid syndrome (APS) affects coagulation and the brain by autoimmune mechanisms. The major antigen in APS is beta-2-glycoprotein I (β2-GPI) is known to complex with annexin A2 (ANXA2), and antibodies to ANXA2 have been described in APS. We measured these antibodies in mice with experimental APS (eAPS) induced by immunization with β2-GPI. Sera of these mice reacted significantly with recombinant ANXA2 by enzyme-linked immunosorbent assay (ELISA) and the eAPS mice had significantly high levels of immunoglobulin G (IgG) in the brain by immunoblot assays compared to adjuvant immunized controls. Immunoprecipitation performed by mixing eAPS brain tissue with protein-G beads resulted in identification of two autoantigens unique to the eAPS group, one of which was ANXA2. In order to study more directly and methodically the specific role of anti-ANXA2 antibodies in APS, we immunized mice with β2-GPI which contained no ANXA2 or with ANXA2 and measured antibodies to these proteins. Levels of antibodies to ANXA2 measured by ELISA were 0.72 ± 0.007 arbitrary units (a.u), 0.24 ± 0.03 and 0.02 ± 0.01 a.u for sera from ANXA2, β2-GPI and control mice, respectively (p < 0.0001 and p = 0.037 for the comparison of the ANXA2 and β2-GPI groups to the controls). Purified IgG from β2-GPI sera did not show cross-binding with ANXA2. Antibodies to β2-GPI and phospholipids were found in the β2-GPI immunized group only. The present study suggests an immune response to the β2-GPI-ANXA2 complex in eAPS and provides a novel ANXA2 immunization model which will serve to study the role of ANXA2 antibodies in of APS.

Fish oil attenuates neurologic severity of antiphospholipid syndrome in a mice experimental model

INTRODUCTION

Murine experimental models of antiphospholipid syndrome (eAPLS) showed neurologic dysfunction and therapeutic effect of the anticoagulant enoxaparin is well established. Omega-3 fatty acids and curcumin, tested in neuroinflammation and auto-immunity diseases, might be interesting therapeutic candidates. The aim of this study was to evaluate the effects of these candidates on neurologic severity in eAPLS.

METHODS

One month after immunization of BALB/c mice with beta-2-glycoprotein I, daily treatments were initiated with enoxaparin (1 mg/kg), omega-3 fatty acids (0.5 g/kg), and curcumin (200 mg/kg) for 3 months.

RESULTS

Mortality was significantly decreased by enoxaparin and omega-3 treatments. Fish oil and curcumin group exhibited the highest mean of swimming behavior in forced swim test in surviving mice. Mice under omega-3 fatty acids or curcumin presented low anxiety-like behavior in the elevated plus-maze test. Cerebral histopathology revealed heavy inflammatory infiltrates in cortical and subcortical regions with vacuolization, swelling, and degeneration of astrocytes in the control group, with aggravation under curcumin; no infiltrate was retrieved in enoxaparin and omega-3 groups.

CONCLUSION

Our study is the first to demonstrate a potential therapeutic effect of omega-3 fatty acids in eAPLS. Enoxaparin and omega-3 fatty acids combination would be interesting for further investigation.

Neuropsychological development of children born to patients with systemic lupus erythematosus

To verify the neuropsychological development in the offspring of patients with systemic lupus erythematosus (SLE), 47 children (23 male and 24 female) from affected women were studied. The tests applied were related to the children’s ages: Griffiths scale up to four years, WPPSI and metaphonological tests (MP, evaluating the phonological consciousness) from four to six years of age, WISC-R test and Rey test (evaluating the visual-space abilities) from six years onwards; finally, specific tests for the diagnosis of learning disabilities (LD) between the ages of seven and 13. Intelligence levels were always normal (mean IQ score 106.32; median 104; SD 9.05). Three out of eight examined children failed MP, therefore may develop LD and will need further evaluation later. Fourteen children were specifically studied for LD and three reported scores lower than normal, but only two (who were brothers) were defined dyslexic. Antiphospholipid antibodies (aPL) were positive in the mothers of the three children with impaired LD tests. Other maternal autoantibodies or drugs administered during pregnancy did not seem to be related to LD. In conclusion, maternal SLE does not impair intelligence levels, but may increase the occurrence of LD particularly in male children (2/8 males examined, 25%). Both maternal aPL and genetic background may have pathogenetic implications.

CNS dysfunction in the antiphospholipid syndrome

Though many neurological deficits have been described in the antiphospholipid syndrome (APS), only stroke is well establishedand accepted as a diagnosticcriterion in this disease. We review clinical data obtainedfrom a large series of cases regardingstroke, dementia, epilepsy, chorea, migraine, white matter disease and behavioralchangesin APS or linked to laboratory criteria such as antiphospholipid antibodies (aPL). The contribution of animal models to our understanding of these manifestations of APS is stressed, especially regarding the cognitive and behavioral aspects for which we have established model systems in the mouse. These models utilize immunization of mice with b2-glycoprotein I, a central autoantigen in APS, which induces persistent high levels of aPL. These mice develop hyperactive behavior after a period of four to five months as well as deficits in learning and memory and are potentiallyvaluableas a system in which to study the pathogenesisand treatment of cognitive and behavioral aspects of APS. Another model we have developed, in which IgG from APS patients induce depolarization of brain synaptoneurosomes, may serve as a model for the pathogenesis of epilepsy in APS.

Annexin A2, autoimmunity, anxiety and depression

OBJECTIVES

Antiphospholipid syndrome (APS) is associated with neurological manifestations and one of the novel autoantigens associated with this disease is Annexin A2 (ANXA2). In this work we have examined the effect of high levels of autoantibodies to ANXA2 on the brain in a mouse model.

METHODS

Recombinant ANXA2 emulsified in adjuvant was used to immunize mice while mice immunized with adjuvant only served as controls. At peak antibody levels the animal underwent behavioral and cognitive tests and their brains were examined for ANXA2 immunoglobulin G (IgG) and expression of ANXA2 and the closely linked protein p11.

RESULTS

Very high levels of anti-ANXA2 antibodies (Abs) were associated with reduced anxiety in the open field 13.14% ± 0.89% of the time in the center compared to 8.64% ± 0.91% observed in the control mice (p < 0.001 by t-test). A forced swim test found significantly less depression manifested by immobility in the ANXA2 group. The changes in behavior were accompanied by a significant reduction in serum corticosteroid levels of ANXA2 group compared to controls. Moreover, higher levels of total IgG and p11 expression were found in ANXA2 group brains. Lower levels of circulating anti-ANXA2 Abs were not associated with behavioral changes.

CONCLUSIONS

We have established an animal model with high levels of anti-ANXA2 Abs which induced IgG accumulation in the brain and specific anxiolytic and anti-depressive effects. This model promises to further our understanding of autoimmune disease such as APS and to provide better understanding of the role of the ANXA2-p11 complex in the brain.

Increased Risk of Autism Spectrum Disorders in Children Born to Women With Systemic Lupus Erythematosus: Results From a Large Population-Based Cohort

OBJECTIVE

In utero exposure to maternal antibodies and cytokines are potential risk factors for autism spectrum disorders (ASDs). The aim of this study was to determine whether children born to mothers with systemic lupus erythematosus (SLE) have an increased risk of ASD compared to children born to mothers without SLE.

METHODS

The study population was derived from the Offspring of SLE Mothers Registry (OSLER), a large population-based cohort identified through healthcare databases in Quebec (1989-2009) comprising all women who had ≥1 hospitalization for a delivery (stillbirth or live birth) after SLE diagnosis. As general population controls, a randomly selected group of women without SLE was matched ≥4:1 to the mothers with SLE for age and year of delivery. Children born live to mothers with SLE and those born live to matched controls were identified, and a recorded diagnosis of ASD was ascertained for each child. Multivariate analyses were performed to adjust for parents' demographic characteristics, sex, birth order of the child, maternal comorbidities, and obstetric complications.

RESULTS

In total, 509 women with SLE had 719 children, and 5,824 matched controls had 8,493 children. Children born to women with SLE were more frequently found to have a diagnosis of ASD compared to controls (frequency of recorded ASDs 1.4% [95% confidence interval (95% CI) 0.8-2.5] versus 0.6% [95% CI 0.5-0.8]), a difference of 0.8% (95% CI 0.1-1.9). The mean age at ASD diagnosis was younger in offspring of SLE mothers (mean 3.8 years, 95% CI 1.8-5.8) compared to offspring of controls (mean 5.7 years, 95% CI 4.9-6.5). In primary multivariate analysis, SLE offspring had a substantially increased risk of ASD compared to controls (odds ratio 2.19, 95% CI 1.09-4.39).

CONCLUSION

Compared to children from the general population, children born to women with SLE have an increased risk of ASD, although, in absolute terms, it represents a rare outcome. These hypothesis-generating data provide direction for additional studies of maternal autoimmunity and ASD risk.

Frontotemporal Dementia with Motor Neuron Disease in a Patient with Antiphospholipid Syndrome: A Case Report

Background

Frontotemporal dementia (FTD) with motor neuron disease (MND) is a syndrome of progressive changes in behavior, language, muscle weakness and atrophy due to loss of function of neurons in the frontal and temporal lobes and in motor neurons. Etiology and pathogenesis of FTD with MND are still uncertain.

Case Report

A 71-year-old man presented with a 2-year history of progressive muscle weakness and cognitive deficits. We diagnosed this patient as FTD with MND by neurological examination, electromyography, brain imaging and neuro-psychological evaluation. We also confirmed antiphospholipid syndrome (APS) in this patient as a way to rule out secondary causes of MND.

Conclusions

This was a very rare case of FTD with MND in APS. We should focus study on the possible role of autoimmune pathogenesis in FTD with MND.

Mice with experimental antiphospholipid syndrome display hippocampal dysfunction and a reduction of dendritic complexity in hippocampal CA1 neurones

AIMS

The antiphospholipid syndrome (APS) is an autoimmune disease characterized by high titres of auto-antibodies (aPL) leading to thrombosis and consequent infarcts. However, many affected patients develop neurological symptoms in the absence of stroke. Similarly, in a mouse model of this disease (eAPS), animals consistently develop behavioural abnormalities despite lack of ischemic brain injury. Therefore, the present study was designed to identify structural alterations of hippocampal neurones underlying the neurological symptoms in eAPS.

METHODS

Adult female Balb/C mice were subjected to either induction of eAPS by immunization with β2-Glycoprotein 1 or to a control group. After sixteen weeks animals underwent behavioural and cognitive testing using Staircase test (experiment 1 and 2) and Y-maze alternation test (experiment 1) and were tested for serum aPL levels (both experiments). Animals of experiment 1 (n = 7/group) were used for hippocampal neurone analysis using Golgi-Cox staining. Animals of experiment 2 (n = 7/group) were used to analyse molecular markers of total dendritic integrity (MAP2), presynaptic plasticity (synaptobrevin 2/VAMP2) and dendritic spines (synaptopodin) using immunohistochemistry.

RESULTS

eAPS mice developed increased aPL titres and presented with abnormal behaviour and impaired short term memory. Further, they revealed a reduction of dendritic complexity of hippocampal CA1 neurones as reflected by decreased dendritic length, arborization and spine density, respectively. Additional decrease of the spine-associated protein expression of Synaptopodin points to dendritic spines as major targets in the pathological process.

CONCLUSION

Reduction of hippocampal dendritic complexity may represent the structural basis for the behavioural and cognitive abnormalities of eAPS mice.

Obstetrical APS: is there a place for hydroxychloroquine to improve the pregnancy outcome?

The use of the conventional APS treatment (the combination of low-dose aspirin and LMWH) dramatically improved the obstetrical prognosis in primary obstetrical APS (OAPS). The persistence of adverse pregnancy outcome raises the need to find other drugs to improve obstetrical outcome. Hydroxychloroquine is widely used in patients with various autoimmune diseases, particularly SLE. Antimalarials have many anti-inflammatory, anti-aggregant and immune-regulatory properties: they inhibit phospholipase activity, stabilize lysosomal membranes, block the production of several pro-inflammatory cytokines and, in addition, impair complement-dependent antigen-antibody reactions. There is ample evidence of protective effects of hydroxychloroquine in OAPS similar to the situation in SLE arising from in vitro studies of pathophysiological working mechanism of hydroxychloroquine. However, the clinical data on the use of hydroxychloroquine in primary APS are lacking and prospective studies are necessary.

Neurodevelopmental disorders in children born to mothers with systemic lupus erythematosus

Children born to women with systemic lupus erythematosus seem to have a potentially increased risk of neurodevelopmental disorders compared to children born to healthy women. Recent experimental data suggest in utero exposure to maternal antibodies and cytokines as important risk factors for neurodevelopmental disorders. Interestingly, women with systemic lupus erythematosus display high levels of autoantibodies and cytokines, which have been shown, in animal models, to alter fetal brain development and induce behavioral anomalies in offspring. Furthermore, subjects with systemic lupus erythematosus and neurodevelopmental disorders share a common genetic predisposition, which could impair the fetal immune response to in utero immunologic insults. Moreover, systemic lupus erythematosus pregnancies are at increased risk of adverse obstetrical outcomes and medication exposures, which have been implicated as potential risk factors for neurodevelopmental disorders. In this article, we review the current state of knowledge on neurodevelopmental disorders and their potential determinants in systemic lupus erythematosus offspring.

Revisiting the molecular mechanism of neurological manifestations in antiphospholipid syndrome: beyond vascular damage

Antiphospholipid syndrome (APS) is a multiorgan disease often affecting the central nervous system (CNS). Typically, neurological manifestations of APS include thrombosis of cerebral vessels leading to stroke and requiring prompt initiation of treatment with antiplatelet drugs or anticoagulant therapy. In these cases, alterations of the coagulation system at various levels caused by multiple effects of antiphospholipid antibodies (aPL) have been postulated to explain the vascular damage to the CNS in APS. However, several nonvascular neurological manifestations of APS have progressively emerged over the past years. Nonthrombotic, immune-mediated mechanisms altering physiological basal ganglia function have been recently suggested to play a central role in the pathogenesis of these manifestations that include, among others, movement disorders such as chorea and behavioral and cognitive alterations. Similar clinical manifestations have been described in other autoimmune CNS diseases such as anti-NMDAR and anti-VGCK encephalitis, suggesting that the spectrum of immune-mediated basal ganglia disorders is expanding, possibly sharing some pathophysiological mechanisms. In this review, we will focus on thrombotic and nonthrombotic neurological manifestations of APS with particular attention to immune-mediated actions of aPL on the vascular system and the basal ganglia.

Altered receptor binding densities in experimental antiphospholipid syndrome despite only moderately enhanced autoantibody levels and absence of behavioral features

Experimental antiphospholipid syndrome (eAPS) in Balb/c mice causes neuropsychiatric abnormalities including hyperactivity, increased explorative behavior and cognitive deficits. Recently, we have demonstrated that these behavioral changes were linked to an upregulation of serotonergic 5-HT1A receptor binding densities in cortical and hippocampal regions while excitatory and inhibitory neurotransmitter receptors remain largely unchanged. To examine whether the observed behavioral features depend on a critical antibody concentration, mice with only moderately enhanced antiphospholipid antibodies (aPL), about 50-80% of high levels, were analyzed and compared to controls. The staircase test was used to test animals for hyperactivity and explorative behavior. The brains were analyzed for tissue integrity and inflammation. Ligand binding densities of NMDA, AMPA, GABAA, 5-HT1A, M1 and M2 muscarinic acetylcholine receptors, respectively, were analyzed by in vitro receptor autoradiography and compared to brains of mice from our previous study with high levels of aPL. Mice with only moderately enhanced aPL did not develop significant behavioral changes. Brain parenchyma remained intact and neither inflammation nor glial activation was detectable. However, there was a significant decrease of NMDA receptor binding densities in the motor cortex as well as an increase in M1 binding densities in cortical and hippocampal regions, whereas the other receptors analyzed were not altered. Lack of neuropsychiatric symptoms may be due to modulations of receptors resulting in normal behavior. In conclusion, our results support the hypothesis that high levels of aPL are required for the manifestation of neuropsychiatric involvement while at lower antibody levels compensatory mechanisms may preserve normal behavior.

Movement disorders in systemic lupus erythematosus and the antiphospholipid syndrome

Movement disorders (MDs), particularly chorea, may be the presenting neurological complication of systemic lupus erythematosus (SLE) and the antiphospholipid syndrome (APS), but the association is not often initially recognized. Current evidence suggests an autoimmune mechanism related to antiphospholipid antibodies in these two conditions, although the antigenic target within the central nervous system has not yet been identified. Based on a comprehensive review of the literature, this article summarizes the current knowledge on MDs in SLE and APS. A high index of suspicion is required to make an early diagnosis and initiate appropriate treatment to provide symptomatic relief and to prevent other systemic complications related to the autoimmune process.

Coagulopathy triggered autoimmunity: experimental antiphospholipid syndrome in factor V Leiden mice

BACKGROUND

We investigated interactions between genetically and autoimmune-mediated coagulopathies by inducing experimental antiphospholipid syndrome (eAPS) in mice carrying the factor V Leiden (FVL) mutation.

METHODS

eAPS was induced in heterozygous and homozygous FVL transgenic mice (C57BL/6 background) by immunization with β(2)-glycoprotein I (β(2)-GPI). Autoantibody levels were measured at 1 and 5 months post-immunization. Mice were tested at 4 months post-immunization for behavior and cognitive function in the staircase, elevated plus-maze, and swim T-maze tests. Brains were removed and analyzed by immunohistochemistry for inflammatory markers and neurodegenerative processes.

RESULTS

A single immunization with β(2)-GPI induced significantly higher and longer-lasting immune responses, and this was dependent on the number of FVL alleles. At 1 and 5 months post-immunization, levels of antibodies rose from 1.17 ± 0.07 to 1.62 ± 0.17 (optical density units; ODU) in homozygous FVL mice, compared with stable levels of 0.59 ± 0.17 and 0.48 ± 0.16 ODU in heterozygous FVL mice and a drop from 1.62 ± 0.21 to 0.61 ± 0.13 ODU in wild-type mice. Behavioral and cognitive clinical features of eAPS were also correlated with FVL allele load, as assessed by the elevated plus-maze (altered anxiety), staircase (hyperactivity and higher exploration), and swim T-maze (impaired learning) tests. Histological studies identified significant neurodegenerative changes in both grey and white matter in the eAPS-FVL brains. In spite of the potential interaction of two prothrombotic disease states, there were no ischemic lesions seen in this group.

CONCLUSIONS

The results indicate that genetically mediated coagulopathies increase the risk of developing coagulation-targeted autoimmune responses, and suggest the importance of antibody-mediated neurodegenerative processes in the brain in APS.

Neurological impairment in experimental antiphospholipid syndrome is associated with increased ligand binding to hippocampal and cortical serotonergic 5-HT1A receptors

The antiphospholipid syndrome (APS) is an autoimmune disease where the presence of high titers of circulating autoantibodies causes thrombosis with consecutive infarcts. In experimental APS (eAPS), a mouse model of APS, behavioral abnormalities develop in the absence of vessel occlusion or infarcts. Using brain hemispheres of control and eAPS mice with documented neurological and cognitive deficits, we checked for lymphocytic infiltration, activation of glia and macrophages, as well as alterations of ligand binding densities of various neurotransmitter receptors to unravel the molecular basis of this abnormal behavior. Lymphocytic infiltrates were immunohistochemically characterized using antibodies against CD3, CD4, CD8 and forkhead box P3 (Foxp3), respectively. GFAP, Iba1 and CD68-immunohistochemistry was performed, to check for activation of astrocytes, microglia and macrophages. Ligand binding densities of NMDA, AMPA, GABAA and 5-HT1A receptors were analyzed by in vitro receptor autoradiography. No significant inflammatory reaction occurred in eAPS mice. There was neither activation of astrocytes or microglia nor accumulation of macrophages. Binding values of excitatory and inhibitory neurotransmitter receptors were largely unchanged. However, ligand binding densities of the modulatory serotonergic 5-HT1A receptors in the hippocampus and in the primary somatosensory cortex of eAPS mice were significantly upregulated which is suggested to induce the behavioral abnormalities observed.

European registry of babies born to mothers with antiphospholipid syndrome

Objectives

This study aimed to describe the long-term outcome and immunological status of children born to mothers with antiphospholipid syndrome, to determine the factors responsible for childhood abnormalities, and to correlate the child's immunological profile with their mothers.

Methods

A prospective follow-up of a European multicentre cohort was conducted. The follow-up consisted of clinical examination, growth data, neurodevelopmental milestones and antiphospholipid antibodies (APL) screening. Children were examined at 3, 9, 24 months and 5 years.

Results

134 children were analysed (female sex in 65 cases, birth weight 3000±500 g, height 48±3 cm). Sixteen per cent had a preterm birth (<37 weeks; n=22), and 14% weighted less than 2500 g at birth (n=19). Neonatal complications were noted in 18 cases (13%), with five infections (4%). During the 5-year follow-up, no thrombosis or systemic lupus erythematosus (SLE) was noted. Four children displayed behavioural abnormalities, which consisted of autism, hyperactive behaviour, feeding disorder with language delay and axial hypotony with psychomotor delay. At birth lupus anticoagulant was present in four (4%), anticardiolipin antibodies (ACL) IgG in 18 (16%), anti-β₂ glycoprotein-I (anti-β2GPI) IgG/M in 16 (15%) and three (3%), respectively. ACL IgG and anti-β2GPI disappeared at 6 months in nine (17%) and nine (18%), whereas APL persisted in 10% of children. ACL and anti-β2GPI IgG were correlated with the same mother's antibodies before 6 months of age (p<0.05).

Conclusion

Despite the presence of APL in children, thrombosis or SLE were not observed. The presence of neurodevelopmental abnormalities seems to be more important in these children, and could justify long-term follow-up.

Adjuvant immunization induces high levels of pathogenic antiphospholipid antibodies in genetically prone mice: another facet of the ASIA syndrome

Adjuvants may induce autoimmune diseases in susceptible individuals, a phenomenon recently defined as autoimmune/inflammatory syndrome induced by adjuvants (ASIA). Patients with both antiphospholipid antibodies (aPL) and the genetic coagulopathy factor V Leiden (FVL) are frequently found. We therefore evaluated whether adjuvant can induce aPL in heterozygous FVL mice. aPL were measured in naïve mice and at 1 and 5 months after immunization with either complete or incomplete Freund's adjuvant (CFA, IFA) in FVL and control C57/B6 background mice. We defined antibody levels 3 SD above the mean of C57/B6 mice immunized with adjuvant as positive (specificity of 99%). For β(2)GPI-dependent aPL, 28.6% (6/21) of FVL mice 5 months after immunization with adjuvant (both IFA and CFA) were positive compared with 4.8% (1/22) of FVL mice 1 month after adjuvant and 0% of naïve FVL and C57/B6 mice (0/16, p < 0.001). aPL levels correlated with behavioral hyperactivity in the staircase test. FVL mice immunized with adjuvant did not develop β(2)GPI-independent aPL. We hypothesize that the FVL aPL association is not a coincidence, but that chronic coagulation defects combined with external inflammatory stimuli analogous to adjuvant may induce aPL and also antiphospholipid syndrome, thus supporting the notion of ASIA.

Neurocognitive dysfunction in systemic lupus erythematosus: association with antiphospholipid antibodies, disease activity and chronic damage

INTRODUCTION

Systemic lupus erythematosus (SLE) is characterized by frequent neuropsychiatric involvement, which includes cognitive impairment (CI). We aimed at assessing CI in a cohort of Italian SLE patients by using a wide range of neurocognitive tests specifically designed to evaluate the fronto-subcortical dysfunction. Furthermore, we aimed at testing whether CI in SLE is associated with serum autoantibodies, disease activity and chronic damage.

METHODS

Fifty-eight consecutive patients were enrolled. Study protocol included data collection, evaluation of serum levels of ANA, anti-dsDNA, anti-cardiolipin, anti-β(2)-glycoprotein I, anti-P ribosomal, anti-endothelial cell, and anti-Nedd5 antibodies. SLEDAI-2000 and SLICC were used to assess disease activity and chronic damage. Patients were administered a test battery specifically designed to detect fronto-subcortical dysfunction across five domains: memory, attention, abstract reasoning, executive function and visuospatial function. For each patient, the raw scores from each test were compared with published norms, then transformed into Z scores (deviation from normal mean), and finally summed in the Global Cognitive Dysfunction score (GCDs).

RESULTS

Nineteen percent of patients had mild GCDs impairment (GCDs 2-3), 7% moderate (GCDs 4-5) and 5% severe (GCDs≥6). The visuospatial domain was the most compromised (MDZs = -0.89±1.23). Anti-cardiolipin IgM levels were associated with visuospatial domain impairment (r = 0.331, P = 0.005). SLEDAI correlated with GCDs, and attentional and executive domains; SLICC correlated with GCDs, and with visuospatial and attentional domains impairment.

CONCLUSIONS

Anti-phospholipids, disease activity, and chronic damage are associated with cognitive dysfunction in SLE. The use of a wide spectrum of tests allowed for a better selection of the relevant factors involved in SLE cognitive dysfunction, and standardized neuropsychological testing methods should be used for routine assessment of SLE patients.

Significant changes in the levels of secreted cytokines in brains of experimental antiphospholipid syndrome mice

Antiphospholipid syndrome (APS) is characterized by thromboses and neuropsychiatric manifestations possibly linked to brain inflammation. In order to examine the levels of proinflammatory and anti-inflammatory cytokines in experimental APS (eAPS) mice brains, we measured the levels of TNF-α, IFN-γ, and IL-10 in brain homogenates (cytosolic fractions) and in brain slices (secreted level) at 6, 15, and 24 weeks after immunization. We induced eAPS by immunization of Balb/c mice with β(2)-glycoprotein I (β(2)GPI), the major autoantigen in the disease and controls with adjuvant alone. We found increased levels of secreted TNF-α in eAPS mice for the entire experiment period. Cytosolic and secreted IL-10 and IFN-γ levels in eAPS mice were lower at 6 and 15 weeks and higher at 24 weeks after immunization. The results suggest that brain disease in APS is associated with significant and complex changes in proinflammatory and anti-inflammatory cytokines.

Cognitive impairment in antiphospholipid syndrome: evidence from animal models

Although antiphospholipid syndrome (APS) is a multisystem prothrombotic condition, its inflammatory nature has been increasingly recognized in recent years. Stroke and transitory ischemic attacks are the neurological manifestations included in APS criteria, however many other neurological involvements have been attributed to antiphospholipid antibodies (aPL), such as seizures, transverse myelitis, and cognitive impairment. In this article we will review evidence from animal model that explain the role of aPL in cognition.

Neurodevelopment in the offspring of Japanese systemic lupus erythematosus patients

OBJECTIVE

To evaluate pregnancy outcome of systemic lupus erythematosus (SLE) and the neuropsychological outcomes in offspring of SLE mothers.

STUDY DESIGN

Pregnancy outcomes of SLE patients from 1989 to 2006 were determined and the neuropsychological development of the children born to SLE patients was examined suited for their age; Bayley Scales of Infant Development up to four years and Kauffmann Assessment Battery for Children from four years onwards.

RESULTS

Of the 233 deliveries, 58 (24.7%) were preterm, 72 (30.9%) were low-birth-weight, and 46 (19.7%) were IUGR. Twenty-six children enrolled in this study had normal intelligence. The mean MDI and PDI were 95.8+/-10.1 and 94.6+/-14.1, respectively. The mean scores for the Sequential Processing scale, Simultaneous Processing scale, and Mental Processing composite were 103.1+/-13.3, 104.2+/-10.2, and 104.2+/-12.2, respectively. In the children with anti-Ro/SS-A antibody-positive mothers, mean gestational age and birth weight were significantly lower (p<0.05), as a result, the mean score of Sequential Processing and Mental Processing were significantly lower than that of negative mothers. The presence of maternal antiphospholipid antibody was not related to gestational age, birth weight and any score on the intelligence tests, except for the rate of IUGR.

CONCLUSION

The rates of preterm delivery and IUGR were frequent in the SLE patients and careful monitoring and management of the disease during pregnancy are still necessary. We should examine the neurodevelopment of the children born from mothers with anti-Ro/SS-A antibody prospectively.

Hyperactivity induced by antiphospholipid syndrome serum

Antiphospholipid syndrome (APS) is a multisystem disorder characterized by arterial and venous thrombosis, pregnancy morbidity, and neuropsychiatric manifestations. Antiphospholipid IgG injected intracerebroventricularly (i.c.v.) cause behavioral hyperactivity in mice. In the present study we investigated the effects of APS whole-serum i.c.v. administration in female Balb/C mice. Control mice were injected with serum derived from healthy subjects or saline solution. Behavior was assessed by the staircase apparatus which combines locomotor (stair-climbing) exploratory activities and rearing as a measure of anxiety. Mice injected with serum from APS patients or serum from normal subjects showed a trend to an increase in the number of stairs climbed in the APS group. The results suggest a differential effect of specific IgG and other serum components in the CNS manifestations of APS.

Antiphospholipid syndrome induction exacerbates a transgenic Alzheimer disease model on a female background

The antiphospholipid syndrome (APS) is characterized by antiphospholipid antibodies (aPL) and vascular brain disease which is often associated with dementia. We examined the neurodegenerative pathological processes underlying APS by inducing APS in a transgenic animal model of Alzheimer's disease. Female C57B6/SJL mice carrying the APP(695)SWE mutation (Tg2576) and wild-type (wt) controls were immunized with β₂-glycoprotein-I (APS mice) or adjuvant alone (controls) at 4 months of age. At the age of 8 months the APP-APS mice developed high levels of aPL associated with motor hypoactivity in a staircase test (p<0.03 by t-test) and impaired performance in the cognitive T-maze (p<0.02 for main effect of treatment by repeated measures ANOVA) relative to APP-CFA mice and controls. wt-APS and wt-control did not differ significantly in their behavior or cognition. Histological studies revealed mature plaques only in the APP-APS group which also had higher amyloid load and number of activated microglia compared to all other groups. The results indicate a significant interaction between APP genotype and the induction of APS on a female background. The mechanisms involved may also be important in human APS-AD co-morbidity.

Neuropsychiatric lupus and infectious triggers

Infections can act as environmental triggers inducing or promoting systemic lupus erythematosus (SLE) in genetically predisposed individuals. The aim of the present study was to compare the titres of antibodies (Abs) to infectious agents with neuropsychiatric (NPSLE) clinical manifestations. The sera of 260 individuals (120 patients with SLE and 140 geographic controls) were evaluated for the titres of Epstein bar virus (EBV), cytomegalovirus (CMV), toxoplasma, rubella and syphilis Abs using the BioPlex 2200 Multiplexed Immunoassay method (BioRad) and by the ELISA method for Helicobacter pylori and Hepatitis B core Ag. All BioPlex 2200 kits used were in developmental stages. Data analysis was performed using SPSS 9.0 statistical analysis software (SPSS Inc., Chicago, IL, USA, 1999). Correlation analysis indicated that rubella IgM Ab titres were marginally, positively associated with psychosis ( P = 0.09). No other associations were detected between the 17 infectious Abs and five NP manifestations. When the positivity cut-off for anti-rubella IgM Abs was set at three standard deviations above normal, three positive subjects were identified: one patient with psychosis and one with depression, for a total NPSLE prevalence of 33.3%. On the contrary, the prevalence of NPSLE in the remaining subjects was 6.5%. Marginally significant correlations between elevated titres of rubella IgM Ab with psychosis and depression were found. Although this nearly 5-fold increase is not statistically significant, it appears that in a larger sample size, significance would be reached. This is the first study reported that examined the correlation of NPSLE manifestations with anti-infectious Abs.

Antiphospholipid antibodies in blood and cerebrospinal fluids of patients with psychosis

Antiphospholipid antibodies (aPL) have been reported in the cerebrospinal fluids (CSF) of neurology patients but no CSF studies with psychiatric patients exist. We tested serum from 100 hospitalized psychotic patients having hallucinations and/or delusions for aPL. Patients with positive serum aPL findings were asked to submit CSF for aPL testing. Five CSF samples had aPL specificities not found in the patient's serum suggesting the possibility of intrathecal synthesis. Specificity and isotype discordance between CSF and blood aPL in these psychiatric patients implicates a central nervous system independent autoimmune process that may have an underlying association with the pathophysiology of their diseases.

Autoantibodies Involved in Neuropsychiatric SLE and Antiphospholipid Syndrome

OBJECTIVE

We sought (1) to identify and (2) to define the association of all reported antibodies (Abs) with neuropsychiatric lupus (NPSLE), (3) to search for possible mechanisms that are involved in NPSLE, and (4) to determine whether we can recognize a panel of Abs associated with specific neuropsychiatric (NP) manifestations.

METHODS

A MEDLINE search (1975 to 2005) was performed utilizing the following terms: neuropsychiatric lupus, antiphospholipid syndrome, or central nervous system systemic lupus erythematosus matched with the term antibodies.

RESULTS

Twenty Abs (11 brain-specific and 9 systemic) were described in NPSLE patients. These include Abs that target brain-specific antigens (neuronal, ganglioside, synaptosomes, glia, methyl-d-aspartate receptors, lymphocytotoxic) and systemic antigens (nuclear, cytoplasmic, phospholipid, endothelial cells). Cognitive impairment, psychosis, and depression were associated with many Abs. Elevated titers of anticardiolipin Abs (aCL) were reported most often and found in patients with cognitive impairment, psychosis, depression, seizures, chorea, and migraine. No specificity was encountered among brain-specific or systemic Abs for any single NP manifestation. No studies evaluated a specific NP manifestation with the full panel of 20 Abs. A panel of brain-specific and systemic Abs may be helpful in establishing the diagnosis of NPSLE. Postulated mechanisms in experimental models included vascular occlusion and injury by pathogenic Abs in a disrupted blood brain barrier.

CONCLUSIONS

NPSLE is associated with brain-specific and systemic Abs. Cognitive impairment, psychosis, and depression were associated with many Abs, including aCL Abs. Possible mechanisms include vascular occlusion and injury by pathogenic Abs in a disrupted blood brain barrier.