Anthony E. Bolton

Neuroprotective effects of novel phosphatidylglycerol-based phospholipids in the 6-hydroxydopamine model of Parkinson's disease

Administration of VP025 (Vasogen Inc.), a novel drug formulation based on phospholipid nanoparticles incorporating phosphatidylglycerol, has previously been shown to have a neuroprotective effect in the brain. We examined the effect of VP025 in a rat model of Parkinsons disease, the 6‐hydroxydopamine (6‐OHDA) lesion of the medial forebrain bundle. VP025 or phosphate‐buffered saline (PBS) was administered to rats 14 days, 13 days and 1 day before the unilateral 6‐OHDA lesion. Functional integrity of nigrostriatal dopaminergic neurons was assessed 7 and 21 days later by amphetamine‐induced rotational testing and we observed that rotational counts were significantly less in rats that were pretreated with VP025 compared with PBS‐pretreated 6‐OHDA‐lesioned rats. Neurochemical analysis at 10 and 28 days after lesion revealed that VP025 protected against a 6‐OHDA‐induced decrease in concentrations of striatal dopamine and its metabolites. Immunocytochemical studies of the ipsilateral substantia nigra showed that VP025 significantly inhibited 6‐OHDA‐induced loss of dopaminergic neurons. We also observed that increases in immunostaining for activated microglia and for activated p38 in dopaminergic neurons of 6‐OHDA‐lesioned rats were prevented by VP025. This study shows that VP025 has significant protective effects on the 6‐OHDA‐lesioned nigrostriatal pathway and may therefore have potential for the treatment of Parkinsons disease.

Attenuation of LPS-Induced Changes in Synaptic Activity in Rat Hippocampus by Vasogen’s Immune Modulation Therapy

Systemic injection of lipopolysaccharide (LPS) blocks the expression of long-term potentiation in the hippocampus of the rat. This is coupled with increased IL-1β concentration and c-Jun NH2-terminal kinase activity, as well as an increase in the number of cells displaying apoptotic characteristics in the hippocampus. Vasogen’s Immune Modulation Therapy (IMT) is a procedure involving intramuscular administration of syngeneic blood which has been exposed ex vivo to elevated temperature, oxidation and ultraviolet light. We report that Vasogen’s IMT significantly abrogates these LPS-induced effects with a concomitant increase in the concentration of the anti-inflammatory cytokine IL-10. These data suggest that Vasogen’s IMT may play a protective role against the deleterious effects of immune insults in the brain.

The effect of VAS972 on allergic contact hypersensitivity.

Background: Contact hypersensitivity (CHS) is a Th1-mediated immune response that can be down-regulated by immunosuppressive agents such as cyclosporine and environmental stimuli such as ultraviolet light. Recently, an immunomodulation therapy, VAS972, has been developed which is believed to down-regulate the Th1 arm of the immune response. This VAS972 involves modifying autologous blood by controlled exposure to the oxidizing agent ozone and UVC light, at an elevated temperature ex vivo. The processed blood is then administered by intramuscular injection. Objective: To further evaluate the immune modulating effect of VAS972. Methods: We examined the effect of VAS972 treatment on CHS. Contact hypersensitivity was induced with dinitro-fluorobenzene (DNFB) in animals receiving VAS972-processed blood, control blood, or saline. A preliminary study was also conducted to evaluate the effect of plasma and cellular fractions of processed blood. Results: Mice injected with VAS972-processed blood demonstrated a significantly lower (46%) CHS response than controls. Histologic examination of challenged ear skin from control mice displayed edema with a significant lymphocytic infiltration, whereas animals administered processed blood demonstrated a reduction in lymphocytic infiltration. Mice injected with either plasma or the cellular fraction of the VAS972-treated blood also demonstrated a significant suppression (49% and 41%, respectively). Conclusion: The results of this study demonstrated that VAS972 suppresses CHS and cellular infiltration. Furthermore, the plasma and cellular components of the VAS972 treatment were also able to induce immunosuppression. This further supports the hypothesis that VAS972 down-regulates the Th1 arm of the immune response.

The deficit in long-term potentiation induced by chronic administration of amyloid-β is attenuated by treatment of rats with a novel phospholipid-based drug formulation, VP025

Amyloid-beta (Abeta) peptides, the primary component of the amyloid plaques in Alzheimers disease (AD), exert profound effects on neurons in vitro and negatively impact on neuronal function in vivo. One of the consequences of increased Abeta in the brain, either as a result of overexpression of the precursor amyloid precursor protein in transgenic mice, or injection into the brain is a decrease in one form of synaptic plasticity, long-term potentiation (LTP) in the hippocampus. Here we investigated the effect of infusion of Abeta for 28 days on LTP in dentate gyrus of rats and demonstrate that it was profoundly decreased compared with control-treated rats. We show that this effect is accompanied by increased activity of caspase 3, which is an indicator of cell stress. Significantly these changes were attenuated in animals which were pretreated with particles incorporating phosphatidylglycerol (VP025) and the evidence indicated that even when treatment was given 2 weeks after the start of the Abeta infusion, VP025 was capable of attenuating Abeta-induced changes. The evidence suggests that activation of caspase 3 was mediated by an Abeta-induced increase in sphingomyelinase, with the subsequent production of ceramide which is known to have a detrimental effect on neuronal function.

Treatment with phosphotidylglycerol-based nanoparticles prevents motor deficits induced by proteasome inhibition: Implications for Parkinson’s disease

Failure of the ubiquitin-proteasome system to degrade abnormal proteins may underlie the accumulation of alpha-synuclein and dopaminergic neuronal degeneration that occurs in Parkinsons disease. Consequently, a reduction of functional proteasome activity has been implicated in Parkinsons disease. VP025 (Vasogen Inc.) is a preparation of phospholipid nanoparticles incorporating phosphatidylglycerol that has been shown to have neuroprotective effects. We show that VP025 prevents the deficits in motor coordination and dopamine observed in a proteasome inhibitor rat model of PD. Thus, VP025 may have a therapeutic effect on the impairment of dopaminergic-mediated motor activity induced by proteasome inhibition.

A Novel Phospholipid-Based Drug Formulation, VP025, Modulates Age- and LPS-Induced Microglial Activity in the Rat

Background: A common change that occurs with age in the central nervous system is an increase in microglial-associated inflammation. This is usually coupled with an increase in the concentration of the inflammatory cytokine interleukin-1β (IL-1β) in the hippocampus and an inhibition in long-term potentiation. Objectives: To assess the effects of a novel preparation of phospholipid nanoparticles incorporating phosphatidylglycerol, VP025, on inflammatory changes in hippocampus of aged and lipopolysaccharide (LPS)-treated rats. Methods/Results: We report that a possible initial target cell of the putative anti-inflammatory actions of VP025 may be macrophages, as VP025 is engulfed by, and has the capacity to alter the activity of, these cells. VP025 reversed the increase in IFN-γ concentration in supernatant taken from peritoneal macrophages harvested from LPS-treated rats. In addition, markers of microglial activity, major histocompatibility complex class II (MHC II) mRNA expression, CD40 expression and IL-1β concentration were increased, and CD200 expression was reduced, in the hippocampus of these rats. VP025 reversed changes in CD40, IL-1β and CD200 in aged rats, and also restored long-term potentiation in aged and LPS-treated rats. Conclusions: We conclude that VP025 has the ability to modulate the activity of macrophage, microglia and neurons in response to stressors such as ageing and LPS treatment.

Evidence of an anti-inflammatory role for Vasogen's immune modulation therapy.

We have reported that Vasogen’s immune modulation therapy (IMT), a procedure involving intramuscular administration of autologous/syngeneic blood, which has been exposed ex vivo to increased temperature, UVC light and oxidation, prevents several LPS-induced inflammatory changes in the hippocampus. Here, we investigated neuroprotective effects of IMT in cortical tissue, and report that the treatment acts as an anti-inflammatory and antioxidative agent, reducing the concentration of TNFα and the accumulation of reactive oxygen species. The data couple these changes with an increase in the concentration of the anti-inflammatory cytokine IL-10, and a decrease in activation of the stress-activated protein kinase, c-jun N-terminal kinase. Consistent with these putative protective effects of IMT, we report that the LPS-induced increase in TUNEL staining, which is indicative of cell death, is prevented by IMT.

Acknowledgement to the Reviewers

R. Ader, Rochester, N.Y., USA M. Anthracopoulos, Rio Patras, Greece E.G. Araujo, Rio de Janeiro, Brazil E. Arzt, Buenos Aires, Argentina A. Aubert, Tours, France L. Barbeito, Montevideo, Uruguay M. Bauer, Porto Alegre, Brazil I. Berczi, Winnipeg, Man., Canada H.O. Besedovsky, Marburg, Germany S. Bornstein, Dresden, Germany O. Bottasso, Santa Fe, Argentina S.D. Brain, London, UK A. Buske-Kirschbaum, Dresden, Germany M. Canal, Manchester, UK E. Charmandari, Athens, Greece D. Chiasserini, Perugia, Italy F.A. Costa-Pinto, São Paulo, Brazil M. Dardenne, Paris, France E.G. de Moura, Rio de Janeiro, Brazil K. Dornmair, Martinsried, Germany R.L. Doty, Philadelphia, Pa., USA J. Drouin, Montreal, Que., Canada G.E. Duffield, Notre Dame, Ind., USA A.J. Dunn, Honolulu, Hawaii, USA I. Elenkov, Rome, Italy G.G. Freund, Urbana, Ill., USA R. Furlan, Milan, Italy R.C. Gaillard, Lausanne, Switzerland Y. Gidron, Tilburg, The Netherlands N. Gilhus, Bergen, Norway F. Haour, Paris, France K. Hirata, Kyushu, Japan S.K. Jindal, Chandigarh, India J. Kasckow , Pittsburgh, Pa., USA T. Katafuchi, Fukuoka, Japan

Neuroimmunomodulation of Inflammatory, Autoimmune and Allergic Diseases

50 Neuroimmunomodulation 2002–03;10:47–72 Abstracts Neuroimmune Regulations in the Brain