The inflammatory response in stroke.

Inflammation and glial responses in ischemic brain lesions

Epidemiology of the Antiphospholipid Antibody Syndrome

The antiphospholipid syndrome (APS) is defined by the presence of anti-phospholipid antibodies (aPLs) and venous or arterial thrombosis, recurrent pregnancy loss, or thrombocytopenia. The syndrome can be either primary or secondary to an underlying condition, most commonly systemic lupus erythematosus (SLE). Echocardiographic studies have disclosed heart valve abnormalities in about a third of patients with primary APS. SLE patients with aPLs have a higher prevalence of valvular involvement than those without these antibodies. Valvular lesions associated with aPLs occur as valve masses (nonbacterial vegetations) or thickening. These two morphological alterations can be combined and are thought to reflect the same pathological process. Both can be associated with valve dysfunction, although such association is much more common with the latter alteration. The predominant functional abnormality is regurgitation; stenosis is rare. The mitral valve is mainly affected, followed by the aortic valve. Valvular involvement usually does not cause clinical valvular heart disease. The presence of aPLs seems to further increase the risk for thromboembolic complications, mainly cerebrovascular, posed by valve lesions. Superadded bacterial endocarditis is rare but may be difficult to distinguish from pseudoinfective endocarditis. The current therapeutic guidelines are those for APS in general. Secondary antithrombotic prevention with long-term, high-intensity oral anticoagulation is advised. The efficacy of aspirin, either alone or in combination, is yet to be assessed. Corticosteroids are not beneficial and may even facilitate valve damage. Immunosuppressive agents should only be used for the treatment of an underlying condition. Current data suggest a role for aPLs in the pathogenesis of valvular lesions. aPLs may promote the formation of valve thrombi. These antibodies may also act by another mechanism, as indicated by the finding of subendothelial deposits of immunoglobulins, including anti-cardiolipin antibodies, and of colocalized complement components in deformed valves from patients with APS.

Heart Valve Involvement (Libman-Sacks Endocarditis) in the Antiphospholipid Syndrome

As part of the neurovascular unit, the blood-brain barrier (BBB) is a unique, dynamic regulatory boundary that limits and regulates the exchange of molecules, ions, and cells between the blood and ...

Neuroinflammatory mechanisms of blood-brain barrier damage in ischemic stroke.

The Hemostasis and Thrombosis Laboratory at the Oregon Health Sciences University identified 80 patients with significantly elevated anticardiolipin antibody (ACLA) levels. We reviewed all of their available medical records and found that 25 of these patients had associated neurological symptoms or disorders. These symptoms and disorders could be grouped into four distinct clinical patterns comprising encephalopathy, multiple cerebral infarctions, migraine-like headaches, and visual abnormalities including amaurosis fugax and ischemic optic neuropathy. Cerebral ischemia best explained these neurological dysfunctions. There was no correlation between the presence or absence of neurological disease and ACLA levels, but ACLA levels were higher in patients with encephalopathy than in others with neurological involvement (p less than 0.05). How neurological dysfunction and the presence of these antiphospholipid antibodies are related remains to be clarified. Nevertheless, in patients with unexplained cerebral ischemia, establishing the presence of ACLA may have prognostic and therapeutic importance. In particular, acute immunosuppressive therapy and plasmapheresis may be useful in patients with acute ischemic encephalopathy.

Neurological disease associated with antiphospholipid antibodies.

Although treatment with agents that block leukocyte function, including anti-ICAM-1 and doxycycline, reduces experimental central nervous system (CNS) ischemic injury, it is not known how leukocyte subset accumulation is affected by these agents. Using the rat two-vessel occlusion model and immunohistochemistry, we investigated granulocyte (PMN) and monocyte/macrophage (Mφ) accumulation at 1 and 4 d postischemia. A total of 24 animals were randomized to sham surgery, or to ischemia with saline, anti-ICAM-1, or doxycycline treatments. No leukocytes were observed in sham animals. At 24 h postischemia, there was a moderate infiltration of PMN and Mφ in untreated animals that was significantly decreased with either treatment. At 4 d after ischemia no PMN were identified, with extensive Mφ accumulation occurring in untreated animals that was only partially reduced with doxycycline treatment. These results confirm that both anti-ICAM-1 and doxycycline treatments reduce PMN and Mφ infiltration at 24 h. Delayed Mφ accumulation occurs despite treatment, suggesting that some of these cells represent transformed resident microglia.

Bruce M. Coull

Papers

Neurological disease associated with antiphospholipid antibodies.

The influence of antiadhesion therapies on leukocyte subset accumulation in central nervous system ischemia in rats