Anti-N-Methyl-D-Aspartic Acid Receptor 2 (Anti-NR2) Antibody in Neuropsychiatric Lupus Serum Damages the Blood-Brain Barrier and Enters the Brain

Depression in systemic lupus erythematosus: A manifestation of microcirculation dysfunction?

OBJECTIVES

Depression is highly prevalent among systemic lupus erythematosus (SLE) patients. Brain hypoperfusion in neuropsychiatric SLE patients might be associated with emotional difficulties. However, no previous study examined possible associations of depression with brain oxygenation during a mild physical stress in non-neuropsychiatric SLE patients. Our study aimed to identify possible differences in cerebral oxygenation during exercise in SLE patients with and without depressive symptoms using near-infrared spectroscopy (NIRS) and examine possible underlying mechanisms through evaluation of vascular cell adhesion molecule 1 (VCAM-1) levels.

METHODS

SLE patients without a known neuropsychiatric history or treatment with antidepressants or antipsychotic drugs were enrolled. Participants were assigned into groups based on Beck's Depression Inventory I (BDI-I). Patients with BDI-I score ≥10 comprised the SLE-depression group and those with BDI-I score <9 the SLE-non-depression group. All participants underwent a protocol involving a seated rest, a 3-min handgrip exercise (at 30% of maximal strength), and a 3-min recovery. NIRS was used to monitor changes in cerebral oxygenated hemoglobin (O2Hb), deoxygenated (HHb), and total hemoglobin (tHb). VCAM-1 levels were measured in serum samples.

RESULTS

Twenty-three patients were enrolled. During exercise, the SLE-depression group exhibited a significantly lower increase in cerebral O2Hb [(peak-O2Hb (p = 0.039); O2Hb-area under the curve, AUC, p = 0.027) vs. SLE-non-depression group. BDI-I score was inversely correlated with AUC (rho = -0.493, p = 0.017) and positively correlated with VCAM-1 levels (rho = 0.501, p = 0.034).

CONCLUSION

This study suggests a possible association between emotional abnormalities and microvascular impairment (cerebral oxygenation and endothelial dysfunction) in SLE However, larger studies are needed to confirm these results.

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.

Autoantibody-associated psychiatric syndromes: a systematic literature review resulting in 145 cases

BACKGROUND

Autoimmune encephalitis (AE) is an important consideration during the diagnostic work-up of secondary mental disorders. Indeed, isolated psychiatric syndromes have been described in case reports of patients with underlying AE. Therefore, the authors performed a systematic literature review of published cases with AE that have predominant psychiatric/neurocognitive manifestations. The aim of this paper is to present the clinical characteristics of these patients.

METHODS

The authors conducted a systematic Medline search via Ovid, looking for case reports/series of AEs with antineuronal autoantibodies (Abs) against cell surface/intracellular antigens combined with predominant psychiatric/neurocognitive syndromes. The same was done for patients with Hashimoto encephalopathy/SREAT. Only patients with signs of immunological brain involvement or tumors in their diagnostic investigations or improvement under immunomodulatory drugs were included.

RESULTS

We identified 145 patients with AE mimicking predominant psychiatric/neurocognitive syndromes. Of these cases, 64% were female, and the mean age among all patients was 43.9 (±22.1) years. Most of the patients had Abs against neuronal cell surface antigens (55%), most frequently against the NMDA-receptor (N = 46). Amnestic/dementia-like (39%) and schizophreniform (34%) syndromes were the most frequently reported. Cerebrospinal fluid changes were found in 78%, electroencephalography abnormalities in 61%, and magnetic resonance imaging pathologies in 51% of the patients. Immunomodulatory treatment was performed in 87% of the cases, and 94% of the patients responded to treatment.

CONCLUSIONS

Our findings indicate that AEs can mimic predominant psychiatric and neurocognitive disorders, such as schizophreniform psychoses or neurodegenerative dementia, and that affected patients can be treated successfully with immunomodulatory drugs.

Anti-NR2 glutamate receptor antibodies as an early biomarker of cerebral small vessel disease

OBJECTIVES

Cerebral small vessel disease (SVD) associated with age and vascular risk factors is one of the leading causes of cognitive disorders as well as ischemic and hemorrhagic strokes. The pathogenesis of this disease has not been fully understood yet. The previously established association of the antibodies against the NR2 subunit of the NMDA receptor (NR2ab) with the mechanisms of SVD such as ischemia and blood-brain barrier (BBB) disruption, might suggest their importance in the brain damage.

DESIGN & METHODS

We studied the NR2ab serum level in 70 patients (45 females, 61.1 ± 6.3 y.o.) with different severity of cognitive impairment and MRI features of SVD and 20 healthy volunteers (12 females, 58.5 ± 6.4 y.o.).

RESULTS

The elevated level of NR2ab was associated with subjective cognitive impairment (SCI) (p = 0.028) and mild cognitive impairment (MCI) (p = 0.017), Fazekas grade (F) 2 (p = 0,002) and F3 (p = 0,009) of white matter hyperintensities (WMH) and the numbers of lacunes in the cerebral white matter (less than 5) (p = 0,039).

CONCLUSION

The detected increase in serum NR2ab level in patients with SCI, as well as the minimal amount of white matter lacunes, is most likely caused by hypoxia-induced endothelial damage in the early stage of SVD. Normal NR2ab values in patients with F1 WMH, the increased NR2ab level in patients with F2 and F3 WMH and those with the minimal number of lacunes can indicate that NR2bs are involved in diffuse brain damage due to hypoxia-induced loss of BBB integrity.

The management of neuropsychiatric lupus in the 21st century: still so many unmet needs?

Neuropsychiatric (NP) events occur in the majority of patients with SLE and predominantly affect the CNS in addition to the peripheral and autonomic systems. Approximately 30% of all NP events are attributable to SLE (NPSLE) and present most frequently around the time of SLE onset. NPSLE is associated with increased morbidity and mortality and the proposed pathogenesis includes both ischaemic and neuroinflammatory mechanisms. Following diagnosis and causal attribution, the treatment of NPSLE is tailored to the type of NP event, the predominant putative pathogenic pathway and the activity and severity of the clinical event. There is a dearth of controlled clinical trials to guide management, but therapeutic options include symptomatic, antithrombotic and immunosuppressive agents that are supported by observational cohort studies. Our objective was to review what is currently known about NPSLE and to identify deficiencies in diagnostic biomarkers, novel therapies and clinical trials for this manifestation of SLE.

Management of inflammatory neurologic and psychiatric manifestations of systemic lupus erythematosus: A systematic review

BACKGROUND

The neurological and psychiatric manifestations of systemic lupus erythematosus (NPSLE) are a heterogeneous group of conditions with variable clinical presentation and significant morbidity and mortality.

OBJECTIVES

Our aim was to comprehensively assess and present the evidence for treatments used in the management of inflammatory NPSLE.

METHODS

Medline, Embase, CINHAL and Cochrane CENTRAL were searched from 1990 to end of March 2019 using key words that related to NPSLE and treatment. Included studies comprised clinical trials, observational studies or case series with ≥5 patients and sufficient data related to treatment and outcome in NPSLE patients.

RESULTS

There were 7222 studies identified in the search, of which 90 were included in the review. There was a notable paucity of clinical trials, with only two randomised controlled trials and one pilot study. Treatment categories included corticosteroids (14 studies), cyclophosphamide (18 studies), synthetic DMARDs (7 studies), biologic therapies (14 studies), therapeutic plasma exchange (6 studies), intravenous immunoglobulin (2 studies), autologous stem cell transplant (3 studies), other therapies (8 studies), combination therapies (6 studies), studies with grouped outcome data (5 studies) and observational studies with therapy-specific associations (7 studies). Corticosteroids are accepted as first line treatment in NPSLE and there is low-moderate evidence supporting their benefit. Moderate evidence, based on consistent data in numerous studies and some trial data, supports the use of cyclophosphamide in the treatment of NPSLE. Limited data support some synthetic DMARDs such as mycophenolate, azathioprine and intrathecal methotrexate. In refractory disease, low-moderate evidence supports rituximab therapy and limited evidence supports benefit following autologous stem cell transplant. Regarding adjuvant treatments, limited evidence favours addition of plasma exchange, intravenous immunoglobulin and hydroxychloroquine. There exists very limited data for other therapies.

CONCLUSION

There are multiple therapeutic options for the management of inflammatory NPSLE including systemic, biologic and interventional therapies; however, currently there is a paucity of high-quality trial data to guide firm recommendations. In order to better understand the optimal treatment of NPSLE and its different subtypes, further well-designed clinical trials are needed.

Advances in the diagnosis, pathogenesis and treatment of neuropsychiatric systemic lupus erythematosus

PURPOSE OF REVIEW

Diagnosing and treating neuropsychiatric systemic lupus erythematosus (NPSLE) remains challenging as the pathogenesis is still being debated. In this review, we discuss studies evaluating recent advances in diagnostic methods, pathogenic mediators and potential treatments.

RECENT FINDINGS

Screening tools used for neurodegenerative diseases were found to be both sensitive and moderately specific for cognitive dysfunction in NPSLE. Neuroimaging can be used to distinguish systemic lupus erythematosus (SLE) patients from healthy controls, but further refinement is needed to differentiate between lupus patients with and without neuropsychiatric manifestations. Elevated levels of specific molecules in the cerebrospinal fluid and/or serum, as well as the presence of certain autoantibodies, have been identified as potential biomarkers in attempts to facilitate a more accurate and objective diagnosis. Among such autoantibodies, anti-NR2 and anti-ribosomal P autoantibodies also have a pathogenic role, although newer studies demonstrate that blood-brain barrier damage may not always be required as previously believed. These and other observations, together with new evidence for disease attenuation after microglial modulation, suggest direct involvement of the central nervous system in NPSLE pathogenesis.

SUMMARY

Neuropsychiatric involvement of SLE includes a variety of symptoms that impact quality of life and patient prognosis. There have been recent advances in improving the diagnosis of NPSLE as well as in dissecting the underlying pathogenesis. The attenuation of neuropsychiatric disease in mouse models demonstrates the potential for targeted therapies, which are based on a clearer understanding of the pathogenesis of NPSLE. Further assessment of these treatments is required in NPSLE patients, as well as the potential use of neuroimaging to distinguish between SLE patients with or without neuropsychiatric manifestations.

Update on the pathogenesis of central nervous system lupus

PROPOSE OF REVIEW

Neuropsychiatric systemic lupus erythematosus (NPSLE) is an emerging frontier in lupus care encompassing a wide spectrum of clinical manifestations. Its pathogenesis remains poorly understood because of the complexity of pathophysiologic mechanisms involved and limited access to tissue. We highlight recent advances in the pathophysiology of neuropsychiatric lupus.

RECENT FINDINGS

Disruption of blood-brain barrier (BBB) facilitating entrance of neurotoxic antibodies into the central nervous system (CNS), neuroinflammation and cerebral ischemia are the key mechanisms. Disruption of the BBB may occur not only at the traditional BBB, but also at the blood-cerebrospinal fluid barrier. Certain autoantibodies, such as anti-N-methyl-D-aspartate receptors, antiribosomal P and antiphospholipid antibodies may cause injury in subsets of patients with diffuse neuropsychiatric disease. Activation of microglia via autoantibodies, interferon-a or other immune reactants, may amplify the inflammatory response and promote neuronal damage. New inflammatory pathways, such as TWEAK/Fn14, Bruton's tyrosine kinase, Nogo-a and ACE may represent additional potential targets of therapy. Novel neuroimaging techniques suggest alterations in brain perfusion and metabolism, increased concentration of neurometabolites, indicative of glial activation, vasculopathy and neuronal impairment.

SUMMARY

NPSLE encompasses a diverse phenotype with distinct pathogenic mechanisms, which could be targeted by novel therapies or repositioning of existing drugs.

Cerebral microvascular and microstructural integrity is regionally altered in patients with systemic lupus erythematosus

Background

To measure regional brain microvascular and microstructural changes in childhood-onset SLE (cSLE) using diffusion-weighted imaging (DWI) at multiple b values and investigate relationships of those measures with neurocognitive function and disease activity.

Methods

In this cross-sectional, case-control study, vascular volume fraction, effective diffusion, parenchymal diffusion, and blood flow parameters were regionally compared in cSLE patients and matched healthy controls. These markers of microvascular and microstructural integrity were derived by diffusion-weighted brain MRI and intravoxel incoherent motion (IVIM) modeling. Formal neurocognitive testing was completed focused on the domains of attention, visuoconstructional ability, working memory, and psychomotor speed. Test scores and measures of disease severity were regressed against regional microvascular integrity parameters among cSLE patients.

Results

Formal cognitive testing confirmed normal cognitive ability among all cSLE patients included in the analysis (n = 11). Nevertheless, reduction in blood volume fraction coincided with increased effective diffusion and flow parameters in cSLE patients vs. controls in posterior brain regions including the cuneus and precuneus. Regional microvascular measures correlated (|r| = 0.54–0.66) with neuropsychiatric scores and disease activity among cSLE patients.

Conclusions

There is imaging evidence, using IVIM, of degraded microvascular integrity in cSLE patients with normal cognitive ability. The observed regional changes correspond with posterior vascular border zones. These outcomes appear consistent with regional gray matter volume loss previously observed in cSLE patients with overt neurocognitive deficits, supporting the notion that adverse vascular changes precede loss of cognitive ability in cSLE. Longitudinal studies are needed to confirm the findings of this initial study.