Interaction of inflammation, thrombosis, aspirin and enoxaparin in CNS experimental antiphospholipid syndrome
Experimental antiphospholipid syndrome (eAPS) induced by immunization with beta(2)-glycoprotein I (beta(2)-GPI) causes behavioral hyperactivity. We assessed the role of thrombotic and inflammatory perivascular factors and standard APS therapies for CNS manifestations. Groups of mice (n=10 per group) were immunized once with beta(2)-GPI (eAPS) or adjuvant (controls) and treated daily from 1 month after immunization with either sham injections, aspirin (1.2 mg/kg) or enoxaparin (1 mg/kg) for 3 months. Serum antiphospholipid antibodies (aPL) and brain levels of tissue necrosis factor-alpha (TNF-alpha) and prostaglandin E (PGE) were then measured by ELISA and thrombin inhibitors by immunoblot. …
Human antiphospholipid antibodies induce TNFα in monocytes via Toll-like receptor 8
The antiphospholipid syndrome (APS) is characterized by recurrent arterial and/or venous thromboses, pregnancy loss and the presence of antiphospholipid antibodies (aPL). One of the discussed mechanisms of this thrombotic activity in APS patients is attributed to TNFalpha secretion in monocytes after aPL stimulation. To investigate this mechanism in detail, we employed a monoclonal aPL and IgG fractions of APS patients for stimulation of human peripheral monocytes. Stimulation with this monoclonal aPL resulted in an increased expression and secretion of TNFalpha, caused by specific upregulation of TLR8 mRNA and protein expression levels. To confirm the specificity of this finding we could d…
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…
Plasma myeloperoxidase levels in acute brain ischaemia and high grade carotid stenosis.
Myeloperoxidase (MPO) is an important oxidative enzyme participating in different stages of cardiovascular disease and predicts prognosis. Little is known about its role in acute cerebrovascular events and carotid plaque vulnerability. In this study, the aim was to assess plasma MPO levels in acute stroke patients and their correlation to stroke severity and stroke outcome.Plasma MPO levels were assessed in patients presenting with acute brain ischaemia within 36 h of symptom onset (n = 144, mean age 64.7 ± 11.6 years, 67% men) and in patients with moderate-to-severe carotid stenosis undergoing carotid artery stenting (n = 51, mean age 66.3 ± 8.4 years, 75% men). Patients presenting with ac…
TLR7 and TLR8 ligands and antiphospholipid antibodies show synergistic effects on the induction of IL-1beta and caspase-1 in monocytes and dendritic cells.
TLRs represent the first line of defense against invading pathogens in the innate immune system. Certain cytokines are important mediators and essentially necessary to assure an appropriately regulated immune response. Recent data gave initial evidence that IL-1beta is one of the most relevant members of these regulating cytokines. We investigated the induction of IL-1beta production in monocytes and pDCs stimulated with ligands for TLR7 and TLR8 and with antiphospholipid antibodies (aPL). Using human monocytes and pDCs for stimulation with specific TLR7 and TLR8 ligands such as resiquimod (R848) and single stranded RNA (RNA42) as well as with a human monoclonal aPL HL5B resulted in a speci…
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 a…
Altered receptor binding densities in experimental antiphospholipid syndrome despite only moderately enhanced autoantibody levels and absence of behavioral features
Abstract 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 staircas…
The experimental antiphospholipid syndrome: an invaluable tool to study autoimmunity-induced neurodegeneration
cells and its activation inhibits their differentiation and remyelination. These suggest a possible role of CNS TLR2 in progressive autoimmune demyelination. Methods: We examined the effects of intra-cerebro-ventricular (ICV) injection of Zymozan, a TLR2 agonist, on the clinical and pathological course of EAE. The survival and clinical scores were monitored; demyelination and axonal loss were quantified by gold-black and Bielschowsky stains, and the nature of neuro-inflammatory response was characterized by TLR2, IBA-1 and CD3 stainings and PCR for immune cytokines. Immune cells were isolated from EAE brain tissue and their proliferative response to the autoantigen (PLP peptide) or Concaval…