Adjuvant immunization induces high levels of pathogenic antiphospholipid antibodies in genetically prone mice: another facet of the ASIA syndrome.

Adjuvants may induce autoimmune diseases in susceptible individuals, a phenomenon recently defined as autoimmune/inflammatory syndrome induced by adjuvants (ASIA). Patients with both antiphospholipid antibodies (aPL) and the genetic coagulopathy factor V Leiden (FVL) are frequently found. We therefore evaluated whether adjuvant can induce aPL in heterozygous FVL mice. aPL were measured in naïve mice and at 1 and 5 months after immunization with either complete or incomplete Freund's adjuvant (CFA, IFA) in FVL and control C57/B6 background mice. We defined antibody levels 3 SD above the mean of C57/B6 mice immunized with adjuvant as positive (specificity of 99%). For ß(2)GPI-dependent aPL, 28.6% (6/21) of FVL mice 5 months after immunization with adjuvant (both IFA and CFA) were positive compared with 4.8% (1/22) of FVL mice 1 month after adjuvant and 0% of naïve FVL and C57/B6 mice (0/16, p < 0.001). aPL levels correlated with behavioral hyperactivity in the staircase test. FVL mice immunized with adjuvant did not develop ß(2)GPI-independent aPL. We hypothesize that the FVL aPL association is not a coincidence, but that chronic coagulation defects combined with external inflammatory stimuli analogous to adjuvant may induce aPL and also antiphospholipid syndrome, thus supporting the notion of ASIA.

The role of apolipoprotein E polymorphisms in levodopa-induced dyskinesia.

OBJECTIVES: To determine the relationship between apolipoprotein E (APOE) polymorphisms to the time to appearance of levodopa-induced dyskinesia (LID) in patients with Parkinson's disease. METHODS: The APOE genotype of 155 consecutive patients treated with levodopa was determined and its effect on the time of onset of LID was examined using Cox regression model, controlling for gender, age of disease onset, time to initiation of levodopa treatment and history of smoking. RESULTS: Two patients were homozygous for the APOE ε2 allele, 7 had ε2/ε3, 1 had ε2/ε4, 130 had ε3/ε3, 12 had ε3/ε4 and 3 had ε4/ε4; LID appeared in 57.4% of the patients, appearing 4.1 ± 3.5 years after the initiation of levodopa treatment. The survival curve for LID was not affected by the APOE genotype (P = 0.34). CONCLUSION: APOE polymorphisms were found not to be associated with either the occurrence or the time to development of LID.

Age-dependent differential expression of BACE splice variants in brain regions of tg2576 mice.

Plaques found in the brains of patients suffering from Alzheimer's disease (AD) mainly consist of beta-amyloid (Abeta), which is produced by sequential cleaving of amyloid precursor protein (APP) by two proteolytic enzymes, beta- and gamma-secretases. Any change in the fine balance between these enzymes and their substrate may contribute to the etio-pathogenesis of AD. Indeed, the protein level and enzymatic activity of beta-secretase (BACE), but not its mRNA level, were found elevated in brain areas of AD patients who suffer a high load of Abeta plaque formation. Similarly, increased BACE activity but no mRNA change was observed in a transgenic mouse model of AD, tg2576, in which over expression of the Swedish mutated human APP leads to Abeta plaque formation and learning deficits. Based on the recent demonstration of four BACE splice variants with different enzymatic activity, the discrepancy between BACE activity and mRNA expression may be explained by the altered BACE alternative splicing. To test this hypothesis, we studied the expression of all BACE splice variants in different brain areas of tg2576 mice at age of 4 months and 1 year old. We found developmental and regional differences between wild-type and tg2576 mice. Our results indicate that over expression of APP in tg2576 mice leads to the altered alternative splicing of BACE and the increase of its enzymatically more active splice variant (I-501).

CNS dysfunction in the antiphospholipid syndrome.

Though many neurological deficits have been described in the antiphospholipid syndrome (APS), only stroke is well established and accepted as a diagnostic criterion in this disease. We review clinical data obtained from a large series of cases regarding stroke, dementia, epilepsy, chorea, migraine, white matter disease and behavioral changes in APS or linked to laboratory criteria such as antiphospholipid antibodies (aPL). The contribution of animal models to our understanding of these manifestations of APS is stressed, especially regarding the cognitive and behavioral aspects for which we have established model systems in the mouse. These models utilize immunization of mice with beta2-glycoprotein I, a central autoantigen in APS, which induces persistent high levels of aPL. These mice develop hyperactive behavior after a period of four to five months as well as deficits in learning and memory and are potentially valuable as a system in which to study the pathogenesis and treatment of cognitive and behavioral aspects of APS. Another model we have developed, in which IgG from APS patients induce depolarization of brain synaptoneurosomes, may serve as a model for the pathogenesis of epilepsy in APS.

Hyperactivity in a mouse model of the antiphospholipid syndrome.

In the antiphospholipid syndrome (APS), antibodies to a complex of phospholipids and beta2-glycoprotein I (beta2-GPI) are associated with recurrent thromboembolic events, spontaneous abortions, thrombocytopenia and central nervous system (CNS) disturbances. Animals immunized with beta2-GPI develop the systemic manifestations of APS but the involvement of the (CNS) in these animals has not been studied. The objective of the present study was to examine mice with induced experimental APS for behavioral changes. Female Balb/C mice were immunized once with beta2-GPI in complete Freund's adjuvant (CFA) or with CFA alone. Four months after immunization the mice were tested in the staircase apparatus and the following two variables were measured: (1) number of rears: and (2) number of stairs climbed by the mice. Immunization with beta2-GPI resulted in elevated levels of circulating anti-negatively charged phospholipids and anti-beta2-GPI antibodies. The APS mice exhibited hyperactive behavior as reflected by more frequent rears (P < 0.023) and higher number of stairs climbed (P < 0.019) by the mice in 3 min. This simple test demonstrated that experimental APS animals are significantly hyperactive and may serve as a marker for CNS involvement in this model.

Behavioral and cognitive deficits occur only after prolonged exposure of mice to antiphospholipid antibodies.

The antiphospholipid (Hughes) syndrome (APS) includes systemic and central nervous system (CNS) pathology associated with antibodies to a complex of phospholipids and beta2-glycoprotein I (beta2-GPI). Beta2-GPI immunized mice develop systemic manifestations of APS and we presently examined CNS manifestations in this APS model. Female BALB/c mice were immunized once with beta2-GPI in complete Freund's adjuvant (CFA) or with CFA alone (controls). A staircase test and a T-maze alternation test were performed to test behavior and cognition in independent groups of mice 6, 12 and 18 weeks following the immunization. The APS mice developed elevated levels of antibodies against negatively charged phospholipids and beta2-GPI. Neurological impairment was detected only 18 weeks after the induction of the APS and consisted of both cognitive (53 +/- 4 vs 71 +/- 3% correct choices in the T-maze alternation for APS vs control mice, P < 0.001) and behavioral changes (higher number of rears (18 +/- 2 vs 11 +/- 1, P < 0.006) and higher number of stairs climbed (12 +/- 2 vs 7 +/- 1, P < 0.02). This is the first report of cognitive deficits in this APS model and demonstrates the time course for the development of previously described behavioral changes. The mechanism involved in these CNS manifestations remains to be elucidated.

Treatment of MRL/lpr mice, a genetic autoimmune model, with the Ras inhibitor, farnesylthiosalicylate (FTS).

Activation and proliferation of lymphocytes requires the active signal transducer Ras. Activation of lymphocytes, associated with autoimmunity, may therefore be modified by S-farnesylthiosalicylic acid (FTS), a synthetic substance that detaches Ras from the inner cell membrane and induces its rapid degradation. The MRL/lpr mouse is a genetic model of a generalized autoimmune disease sharing many features and organ pathology with systemic lupus erythematosus (SLE) and the primary antiphospholipid syndrome (APS). The objective of the present study was to examine the effect of FTS on laboratory and clinical pathology in the MRL/lpr mouse. Female MRL/lpr (n = 50) and MRL/++ control (n = 35) mice were treated intraperitoneally with either FTS (5 mg/kg/day) or saline between 6 and 18 weeks of age. The mice were weighed, tested for proteinuria and lymphadenopathy, lymphocyte proliferation, antibodies, grip strength and behaviour in an open field. FTS treatment resulted in a 50% decrease in splenocyte proliferation to ConA, LPS and a disease specific antigen, beta(2)-glycoprotein-I, and in a significant decrease in serum antibody levels against cardiolipin and dsDNA. Proteinuria and grip strength were normalized and lymphadenopathy and postmortem lymph node and spleen weights were significantly reduced in FTS treated MRL/lpr mice. These findings indicate that modulation of Ras activation has a significant impact on the MRL/lpr model and may represent a new therapeutic approach for the treatment of systemic autoimmune diseases such as SLE and APS.