Antiplatelet and anticoagulant agents for secondary prevention of stroke and other thromboembolic events in people with antiphospholipid syndrome

Innovations in Breaking Barriers: Liposomes as Near-Perfect Drug Carriers in Ischemic Stroke Therapy

Liposomes, noted for their tunable particle size, surface customization, and varied drug delivery capacities, are increasingly acknowledged in therapeutic applications. These vesicles exhibit surface flexibility, enabling the incorporation of targeting moieties or peptides to achieve specific targeting and avoid lysosomal entrapment. Internally, their adaptable architecture permits the inclusion of a broad spectrum of drugs, contingent on their solubility characteristics. This study thoroughly reviews liposome fabrication, surface modifications, and drug release mechanisms post-systemic administration, with a particular emphasis on drugs crossing the blood-brain barrier (BBB) to address lesions. Additionally, the review delves into recent developments in the use of liposomes in ischemic stroke models, offering a comparative evaluation with other nanocarriers like exosomes and nano-micelles, thereby facilitating their clinical advancement.

Bleeding events in thrombotic antiphospholipid syndrome: prevalence, severity, and associated damage accrual

Background

Life-long anticoagulation increases bleeding risk in patients with antiphospholipid syndrome (APS). The Damage Index for Antiphospholipid Syndrome does not include bleeding events in damage accrual.

Objectives

We aimed to characterize the prevalence, severity, and damage associated with bleeding events in patients with APS.

Methods

This was a single-center retrospective analysis of patients with thrombotic APS (2006 Sydney criteria). Bleeding events were reviewed up to 43 years and classified according to the ISTH definitions into 2 groups: 1) major bleedings and 2) nonmajor bleedings (minor bleedings and clinically relevant nonmajor bleedings). Damage events were recorded as bleeding events a) resulting in permanent (>6 months) decrease in organ function and b) complicated by total/partial organ resection.

Results

Among 197 patients (2412 patient-years [PYs] of follow-up), all of whom had been exposed to antithrombotic therapy, 40.6% experienced 167 bleedings (6.9 events per 100 PYs), of whom 61.3% had nonmajor bleedings (77.2% of bleedings: 42.6% minor, 57.4% clinically relevant nonmajor) and 38.8% had major bleedings (22.8% of bleedings; 1.6 events per 100 PYs). Soft/connective tissue was affected in 44.3% of bleedings, and 94.6% were nonmajor bleedings. Central nervous system was affected in 20.9% of bleedings, and 62.9% were major bleedings. Bleeding events were spontaneous in 90.4% of cases, and thrombocytopenia was likely involved in 62.2% of bleedings. Damage occurred in 11.4% of bleedings and affected 7.6% of patients. Most of the damage was associated with central nervous system events (8.4% of all bleedings).

Conclusion

Approximately 40% of patients experienced at least 1 bleeding, and almost 8% of patients were left with organ damage not recognized by the current version of the Damage Index for Antiphospholipid Syndrome.

Neurologic Manifestations of Catastrophic Antiphospholipid Syndrome

PURPOSE OF REVIEW

Understanding of antiphospholipid antibody syndrome (APS), associated neurological manifestations, and disease-directed treatment has grown considerably over the last decade. Herein, we critically review the current and high-yield literature related to the pathophysiology, neurological presentations, and management of APS with particular emphasis on the rare and more fatal subset of APS, catastrophic antiphospholipid syndrome (CAPS).

RECENT FINDINGS

APS may manifest with a variety of neurologic syndromes, with cerebrovascular disease representing the most commonly encountered presentation. Diagnostic evaluation and treatment are often tailored to the specific presentation, with suspicion and testing for antiphospholipid antibodies recommended when neurologic presentations occur atypically or in younger individuals. In CAPS, which is more rapidly progressive with multiorgan involvement, potential alternative microangiopathic syndromes should be carefully considered in the differential diagnosis. To date, anticoagulation with vitamin K antagonists remains the mainstay of therapy in APS while triple therapy with anticoagulation, corticosteroids, and plasma exchange is standard of care in CAPS. Immunotherapy has shown early promise in refractory cases. APS is an autoimmune clinical syndrome with neurologic presentations classically characterized by vascular thrombosis, though recent understandings suggest additional direct immune-mediated phenomena. Our understanding of the underlying pathogenic mechanisms of APS continues to grow and will continue to influence our therapeutic approaches.

Sex Differences in Clinical Characteristics and Prognosis in Primary Thrombotic Antiphospholipid Syndrome

Objectives

This study aimed to investigate whether there are sex differences in clinical characteristics and prognosis in patients with primary thrombotic antiphospholipid syndrome (ptAPS).

Methods

From January 2013 to July 2021, 154 consecutive patients diagnosed with ptAPS were prospectively recruited. Multivariable Cox regression was used to evaluate the association between gender and the composite endpoint including thromboembolic recurrence or all-cause death during follow-up.

Results

Totally, 80 (52%) male and 74 (48%) female patients with ptAPS were included, and men had a higher percentage of smokers/ex-smokers [50 (62%) vs. 6 (8%), p < 0.001] and hyperhomocysteinemia [26 (32%) vs. 9 (12%), p = 0.003]. The baseline thromboembolic events were similar in two genders, except for limb ischemia [15 (19%) in men vs. 1 (1%) in women, p < 0.001]. During a median follow-up of 42 months, the composite endpoint occurred in 30 (38%) male and 15 (20%) female patients (p = 0.019). Male gender [HR 2.499, 95% CI (1.316, 4.743), p = 0.005] and warfarin administration [HR 0.482, 95% CI (0.257, 0.905), p = 0.023] remained independent risk factors for the composite endpoint. Male gender [HR 3.699, 95% CI (1.699, 8.246), p = 0.001] and isolated lupus anticoagulant positivity [HR 2.236, 95% CI (1.039, 4.811), p = 0.040] were independent risk factors for thromboembolic recurrence.

Conclusion

There are sex disparities in the clinical characteristics in patients with ptAPS and the male gender is an independent risk factor for the poor prognosis. Male patients with isolated lupus anticoagulant (LA) positivity have the highest risk of thromboembolic recurrence.

High Levels of Thromboxane (TX) Are Associated with the Sex-Dependent Non-Dipping Phenomenon in Ischemic Stroke Patients

BACKGROUND

Inflammation and high blood pressure (nondipping profile) during the rest/sleep period have been associated with an effect on the incidence of cardiovascular disorders and a more severe course in the ischemic cerebrovascular event. There are no available data on the relationship between dipping status and the pro-inflammatory metabolites of arachidonic acid (AA); therefore, we undertook a study to investigate the influence of thromboxane on the incidence of nondipping among patients after stroke.

METHODS

Sixty-two patients with ischemic stroke (including 34 women and 28 men) were tested for the involvement of thromboxane in the nondipping phenomenon. Subjects were analyzed for the presence of the physiological phenomenon of dipping (DIP group) versus its absence-nondipping (NDIP group). Thromboxane (TX) measurements were performed using liquid chromatography, and blood pressure was measured 24 h a day in all subjects.

RESULTS

The analysis of the thromboxane level in the plasma of patients after ischemic stroke showed significant differences in terms of sex (p = 0.0004). Among women in both groups, the concentration of TX was high, while similar levels were observed in the group of men from the NDIP group. However, when comparing men in the DIP and NDIP groups, a lower TX level was noticeable in the DIP group.

CONCLUSIONS

A higher level of TX may be associated with a disturbance of the physiological phenomenon of DIP in men and women. However, in our opinion, TX is not the main determinant of the DIP phenomenon and, at the same time, other pro-inflammatory factors may also be involved in the occurrence of this singularity.

Clinical Management of Thrombotic Antiphospholipid Syndrome

Thrombotic manifestations of antiphospholipid syndrome are often a therapeutic dilemma and challenge. Despite our increasing knowledge of this relatively new disease, many issues remain widely unknown and controversial. In this review, we summarise the latest literature and guidelines on the management of thrombotic antiphospholipid syndrome. These include the laboratory assays involved in antiphospholipid antibodies (aPL) testing, the use of direct oral anticoagulants in secondary prevention, management of recurrent thrombosis, individuals with isolated aPL, and catastrophic antiphospholipid syndrome. Treatment aims to prevent the potentially fatal and often disabling complications of APS with antithrombotic and cardiovascular risks prevention strategies. Some insights and updates on topical issues in APS are provided. We also include our current practice, which we believe is the pragmatic approach based on the currently available evidence.

Research progress of stem cell therapy for ischemic stroke

Ischemic stroke is a serious cerebrovascular disease with high morbidity, disability and mortality. There is no doubt that the disease has a severe impact on the physical and mental health and quality of life of patients, as well as impose a heavy burden on families and societies. Unfortunately, there has been a lack of effective treatment. This overview reviews the pathophysiology of stem cell therapy in Ischemic stroke, and discuss its effects on neurogenesis, the latest clinical trials, and advances in tracking and monitoring of endogenous and exogenous stem cells.

Use of Direct Oral Anticoagulants in Patients With Antiphospholipid Syndrome: A Systematic Review and Comparison of the International Guidelines

Antiphospholipid antibody syndrome (APS) requires long-term anticoagulation to prevent recurrent thrombosis. Direct oral anticoagulants (DOACs) have been increasingly used in APS patients, but contradictory guidelines recommendations on their use do exist. We performed a systematic review of literature including studies investigating the role of DOACs in APS patients. At this aim, PubMed and Cochrane databases were searched according to PRISMA guidelines. We identified 14 studies which investigated the use of DOACs in patients with APS, of which 3 randomized clinical trials (RCTs), 1 post-hoc analysis of 3 RCTs, 7 case series and 3 cohort studies (2 prospective and 1 retrospective). Among DOACs, rivaroxaban was the most used (n = 531), followed by dabigatran (n = 90) and apixaban (n = 46). Regarding guidelines indications, the 2019 European Society of Cardiology (ESC) and American Society of Hematology (ASH) guidelines recommend against the use of DOACs in all APS patients. The European League Against Rheumatism (EULAR), British Society for Haematology (BSH), and International Society on Thrombosis and Haemostasis (ISTH) guidance provided more detailed indications stating that warfarin should be the first-choice treatment but DOACs may be considered in patients (1) already on a stable anticoagulation with a DOAC, (2) with low-quality anticoagulation by warfarin, (3) unwilling/unable to undergo INR monitoring, (4) with contraindications or serious adverse events under warfarin. Patients with arterial APS or triple positivity should be treated with warfarin while venous APS with single or double positivity may be candidate to DOACs, but high-quality studies are needed.

Neurologic Manifestations of the Antiphospholipid Syndrome - an Update

PURPOSE OF REVIEW

In recent years, the spectrum of neurological manifestations of antiphospholipid syndrome (APS) has been growing. We provide a critical review of the literature with special emphasis on presentation, proposed mechanisms of disease, and treatment of neurological involvement in APS.

RECENT FINDINGS

Although stroke is the most common cause of neurological manifestations in patients with APS, other neurological disorders have been increasingly associated with the disease, including cognitive dysfunction, headache, and epilepsy. Direct oral anticoagulants have failed to show non-inferiority compared to vitamin K antagonists for the prevention of major thrombotic events. Antiphospholipid antibodies are often found in patients with acute COVID-19 but clear evidence supporting an association between these antibodies and the risk of thrombotic events, including stroke and cerebral venous thrombosis, is still lacking. APS patients may present with several distinct neurological manifestations. New criteria will facilitate the classification of patients presenting with increasingly recognized non-criteria neurological manifestations.

Potential Mechanisms and Perspectives in Ischemic Stroke Treatment Using Stem Cell Therapies

Ischemic stroke (IS) remains one of the major causes of death and disability due to the limited ability of central nervous system cells to regenerate and differentiate. Although several advances have been made in stroke therapies in the last decades, there are only a few approaches available to improve IS outcome. In the acute phase of IS, mechanical thrombectomy and the administration of tissue plasminogen activator have been widely used, while aspirin or clopidogrel represents the main therapy used in the subacute or chronic phase. However, in most cases, stroke patients fail to achieve satisfactory functional recovery under the treatments mentioned above. Recently, cell therapy, especially stem cell therapy, has been considered as a novel and potential therapeutic strategy to improve stroke outcome through mechanisms, including cell differentiation, cell replacement, immunomodulation, neural circuit reconstruction, and protective factor release. Different stem cell types, such as mesenchymal stem cells, marrow mononuclear cells, and neural stem cells, have also been considered for stroke therapy. In recent years, many clinical and preclinical studies on cell therapy have been carried out, and numerous results have shown that cell therapy has bright prospects in the treatment of stroke. However, some cell therapy issues are not yet fully understood, such as its optimal parameters including cell type choice, cell doses, and injection routes; therefore, a closer relationship between basic and clinical research is needed. In this review, the role of cell therapy in stroke treatment and its mechanisms was summarized, as well as the function of different stem cell types in stroke treatment and the clinical trials using stem cell therapy to cure stroke, to reveal future insights on stroke-related cell therapy, and to guide further studies.