Antiphospholipid Antibody and Recurrent Ischemic Stroke

Patterns of Cerebrovascular Accidents in Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease that primarily affects young adults. It is characterized by the development of antiphospholipid antibodies (APL) and a wide range of macro- and microvascular symptoms. The primary causes of morbidity and mortality in APS are cardiovascular events. Subclinical atherosclerosis and cardiovascular events are associated with high-risk APL profiles, particularly with the presence of lupus anticoagulant and triple APL positivity (all three APL subtypes), co-existence with systemic lupus erythematosus (SLE), and traditional risk factors like smoking, hypertension, obesity, and hyperlipemia. We present a case series involving three female stroke patients with APS. This series highlights the importance of immunological profiles in all stroke patients.

Antiphospholipid Syndrome and Antibodies Associated With Malignancy and Older Age: A Retrospective Study

BACKGROUND

Antiphospholipid syndrome (APLS) is an established cause of thrombosis and hypercoagulability. However, the clinical characteristics of those with APLS or patients with positive antiphospholipid antibodies (APLA) in the embolic stroke of undetermined source (ESUS) have not been well studied.

METHODS

A retrospective analysis was conducted between January 1, 2010, and December 31, 2020, across all three Mayo Clinic sites. Patients who were included in the study were tested for APLA and had a diagnosis of ESUS. Baseline characteristics, radiographic parameters, and outcome data were collected and compared between those who tested positive for APLS or had positive APLA and those who were negative.

RESULTS

A total of 206 patients were included in the study. Eight (4%) patients were diagnosed with APLS, and 21 (10%) patients had positive APLA. On comparing those with a diagnosis of APLS and those without, patients with APLS were found to be significantly older (75 years old ± 9 vs. 58 years old ± 14, p = 0.001) and were more likely to have a history of cancer (50% vs. 13%, p = 0.012). Those with positive APLA had similar findings of being older (67 years old ±13 vs. 58 years old ± 14 p = 0.003) and more likely to have a history of cancer (29% vs. 8.4% p = 0.027). Radiographically, those with APLS had a higher white matter disease burden (Fazekas score median 2 (IQR 1.5-3) vs. median 1 (IQR 1-2), p = 0.028).

CONCLUSION

Both APLS and positive APLA are associated with older age and a history of malignancy. These findings highlight the importance of considering a hypercoagulable evaluation even in the elderly ESUS population.

Thrombophilia screening in the routine clinical care of children with arterial ischemic stroke

BACKGROUND

Current guidelines recommend thrombophilia evaluation in childhood arterial ischemic stroke, but the impact of screening on management is unknown. The objective of the current study is to report the incidence of thrombophilia identified as part of routine clinical care in the context of available literature reports, and to describe the impact of a diagnosis of thrombophilia on patient management.

METHODS

We conducted a single-institution retrospective chart review for all children with arterial ischemic stroke occurring between January 1, 2009 and January 1, 2021. We collected thrombophilia screening results, stroke etiology, and management. We also reviewed the literature of thrombophilia testing in childhood arterial ischemic stroke published prior to June 30, 2022. Meta-analysis methods were used to assess prevalence rates.

RESULTS

Among children with thrombophilia testing performed, 5% (six of 122 patients) were factor V Leiden heterozygous, 1% (one of 102 patients) were prothrombin gene mutation heterozygous, 1% (one of 122) had protein S deficiency, 20% (23/116 patients) had elevated lipoprotein(a), 3% (three of 110 patients) had elevated homocysteine levels, and 9% (10/112) had elevated antiphospholipid antibodies, only two of whom had persistently elevated levels. There was no change in stroke therapy due to these results. Literature review revealed a wide range of prevalence for most thrombophilia traits, with high cross-study heterogeneity in most cases.

CONCLUSIONS

The rates of thrombophilia in our cohort were consistent with that expected in the general population. The identification of thrombophilia did not alter stroke care. However, some of the results were actionable, prompting evaluation for lipid disorders and patient-specific counseling on cardiovascular risk and risk for venous thrombosis.

Anti-β2-GPI Antibodies Induce Endothelial Cell Expression of Tissue Factor by LRP6 Signal Transduction Pathway Involving Lipid Rafts

In this study we analyzed whether anti-β2-GPI antibodies from patients with APS induce the endothelial cell expression of Tissue Factor (TF) by a LRP6 signal transduction pathway involving lipid rafts. HUVEC were stimulated with affinity purified anti-β2-GPI antibodies. Both LRP6 and β-catenin phosphorylation, as well as TF expression, were evaluated by western blot. Results demonstrated that triggering with affinity purified anti-β2-GPI antibodies induced LRP6 phosphorylation with consequent β-catenin activation, leading to TF expression on the cell surface. Interestingly, the lipid rafts affecting agent methyl-β-cyclodextrin as well as the LRP6 inhibitor Dickkopf 1 (DKK1) partially reduced the anti-β2-GPI antibodies effect, indicating that the anti-β2-GPI effects on TF expression may depend on a signalling transduction pathway involving both lipid rafts and LRP6. An interaction between β2-GPI, LRP6 and PAR-2 within these microdomains was demonstrated by gradient fractionation and coimmunoprecipitation experiments. Thus, anti-β2-GPI antibodies react with their target antigen likely associated to LRP6 and PAR-2 within plasma membrane lipid rafts of the endothelial cell. Anti-β2-GPI binding triggers β-catenin phosphorylation, leading to a procoagulant phenotype characterized by TF expression. These findings deal with a novel signal transduction pathway which provides new insight in the APS pathogenesis, improving the knowledge of valuable therapeutic target(s).

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.

Thrombophilia Testing After Ischemic Stroke: Why, When, and What?

Thrombophilia testing is frequently performed after an ischemic stroke, particularly when cryptogenic. However, there is minimal evidence supporting a significant association between most conditions assessed through thrombophilia testing and ischemic stroke, and the rationale for thrombophilia testing in many clinical situations remains uncertain. In this topical review, we review and contextualize the existing data on the risks, predictors, and outcomes of thrombophilic conditions in patients with ischemic stroke. We report that inherited thrombophilias have an uncertain relationship with ischemic stroke. Conversely, antiphospholipid syndrome, an acquired immune-mediated thrombophilia, seems to be a strong risk factor for arterial thromboembolic events, including ischemic stroke, and especially among young patients. Our findings suggest that certain circumstances may warrant targeted thrombophilia testing, such as stroke in the young, cryptogenic stroke, and high estrogen states. Future prospective studies should investigate the utility and cost effectiveness of thrombophilia testing in various stroke settings, including among patients with patent foramen ovale; as well as the optimal secondary stroke prevention regimen in patients with confirmed thrombophilia, particularly if no other potential stroke mechanism is identified.