Alzheimer Disease: Fernandez F

Giunta B, Fernandez F, Nikolic WV, Obregon D, Rrapo E, Town T, Tan J. · Neuroimmunology Laboratory, Department of Psychiatry, Behavioral Medicine, Institute for Research in Psychiatry, University of South Florida, College of Medicine, Tampa, FL 33613, USA. · J Neuroinflammation. · Pubmed #19014446 links to  free full text

Abstract: Recently, the term "inflammaging" was coined by Franceshci and colleagues to characterize a widely accepted paradigm that ageing is accompanied by a low-grade chronic up-regulation of certain pro-inflammatory responses. Inflammaging differs significantly from the traditional five cardinal features of acute inflammation in that it is characterized by a relative decline in adaptive immunity and T-helper 2 responses and is associated with increased innate immunity by cells of the mononuclear phagocyte lineage. While the over-active innate immunity characteristic of inflammaging may remain subclinical in many elderly individuals, a portion of individuals (postulated to have a "high responder inflammatory genotype") may shift from a state of "normal" or "subclinical" inflammaging to one or more of a number of age-associated diseases. We and others have found that IFN-gamma and other pro-inflammatory cytokines interact with processing and production of Abeta peptide, the pathological hallmark feature of Alzheimer's disease (AD), suggesting that inflammaging may be a "prodrome" to AD. Although conditions of enhanced innate immune response with overproduction of pro-inflammatory proteins are associated with both healthy aging and AD, it is suggested that those who age "well" demonstrate anti-inflammaging mechanisms and biomarkers that likely counteract the adverse immune response of inflammaging. Thus, opposing the features of inflammaging may prevent or treat the symptoms of AD. In this review, we fully characterize the aging immune system. In addition, we explain how three novel treatments, (1) human umbilical cord blood cells (HUCBC), (2) flavanoids, and (3) Abeta vaccination oppose the forces of inflammaging and AD-like pathology in various mouse models.

Rezai-Zadeh K, Arendash GW, Hou H, Fernandez F, Jensen M, Runfeldt M, Shytle RD, Tan J. · Rashid Laboratory for Developmental Neurobiology, Silver Child Development Center, Department of Psychiatry and Behavioral Medicine, and Department of Neurosurgery, University of South Florida, Tampa, FL 33613, USA. · Brain Res. · Pubmed #18457818 No free full text.

Abstract: We previously reported that intraperitoneal (i.p.) injection (20 mg/kg) of (-)-epigallocatechin-3-gallate (EGCG), the main polyphenolic constituent of green tea, decreased beta-amyloid (Abeta) levels and plaques via promotion of the non-amyloidogenic alpha-secretase proteolytic pathway in "Swedish" mutant amyloid precursor protein overexpressing (APPsw, Tg) mice. Here, we find that EGCG administered orally in drinking water (50 mg/kg) similarly reduces Abeta deposition in these mice. Following a six month treatment of an 8 month old cohort, immunohistochemical analysis of coronal sections reveals that plaque burdens were reduced in the cingulate cortex, hippocampus, and entorhinal cortex by 54%, 43%, and 51%, respectively. Congo red plaque burdens were decreased in the cingulate cortex, hippocampus, and entorhinal cortex by 53%, 53%, and 58%, respectively as well. ELISA of brain homogenates of the treatment Tg mice revealed consistent reductions in both Abeta1-40 and 1-42 soluble and insoluble forms. In the present study we also investigated the effect EGCG administration had on tau pathology and cognition in Tg mice. Both i.p. and orally-treated Tg animals were found to have modulated tau profiles, with markedly suppressed sarkosyl-soluble phosphorylated tau isoforms. Radial arm water maze (RAWM) testing for working memory indicated that EGCG provided cognitive benefit to Tg mice with both i.p. and oral administration, although i.p.-treated animals showed a more pronounced benefit because of the greater impairment of their Tg controls at the time of testing. Taken together, these data further the notion of EGCG dietary supplementation as a potentially safe and effective prophylaxis for Alzheimer's disease.

Obregon D, Hou H, Bai Y, Nikolic WV, Mori T, Luo D, Zeng J, Ehrhart J, Fernandez F, Morgan D, Giunta B, Town T, Tan J. · Neuroimmunology Laboratory, Institute for Research in Psychiatry, Department of Psychiatry and Behavioral Medicine, USA. · Neurobiol Dis. · Pubmed #18055209 No free full text.

Abstract: Amyloid-beta (Abeta) immunization efficiently reduces amyloid plaque load and memory impairment in transgenic mouse models of Alzheimer's disease (AD). Active Abeta immunization has also yielded favorable results in a subset of AD patients. However, a small percentage of patients developed severe aseptic meningoencephalitis associated with brain inflammation and infiltration of T-cells. We have shown that blocking the CD40-CD40 ligand (L) interaction mitigates Abeta-induced inflammatory responses and enhances Abeta clearance. Here, we utilized genetic and pharmacologic approaches to test whether CD40-CD40L blockade could enhance the efficacy of Abeta(1-42) immunization, while limiting potentially damaging inflammatory responses. We show that genetic or pharmacologic interruption of the CD40-CD40L interaction enhanced Abeta(1-42) immunization efficacy to reduce cerebral amyloidosis in the PSAPP and Tg2576 mouse models of AD. Potentially deleterious pro-inflammatory immune responses, cerebral amyloid angiopathy (CAA) and cerebral microhemorrhage were reduced or absent in these combined approaches. Pharmacologic blockade of CD40L decreased T-cell neurotoxicity to Abeta-producing neurons. Further reduction of cerebral amyloidosis in Abeta-immunized PSAPP mice completely deficient for CD40 occurred in the absence of Abeta immunoglobulin G (IgG) antibodies or efflux of Abeta from brain to blood, but was rather correlated with anti-inflammatory cytokine profiles and reduced plasma soluble CD40L. These results suggest CD40-CD40L blockade promotes anti-inflammatory cellular immune responses, likely resulting in promotion of microglial phagocytic activity and Abeta clearance without generation of neurotoxic Abeta-reactive T-cells. Thus, combined approaches of Abeta immunotherapy and CD40-CD40L blockade may provide for a safer and more effective Abeta vaccine.

Townsend KP, Town T, Mori T, Lue LF, Shytle D, Sanberg PR, Morgan D, Fernandez F, Flavell RA, Tan J. · Neuroimmunology Laboratory, Department of Psychiatry, University of South Florida College of Medicine, Tampa, USA. · Eur J Immunol. · Pubmed #15688347 No free full text.

Abstract: Although deposition of amyloid beta-peptide (Abeta) as Abeta plaques involves activation of microglia-mediated inflammatory responses, activated microglia ultimately fail to clear Abeta plaques in the brains of either Alzheimer's disease (AD) patients or AD mouse models. Mounting evidence suggests that chronic microglia-mediated immune response during Abeta deposition etiologically contributes to AD pathogenesis by promoting Abeta plaque formation. However, the mechanisms that govern microglia response in the context of cerebral Abeta/beta-amyloid pathology are not well understood. We show that ligation of CD40 by CD40L modulates Abeta-induced innate immune responses in microglia, including decreased microglia phagocytosis of exogenous Abeta(1-42) and increased production of pro-inflammatory cytokines. CD40 ligation in the presence of Abeta(1-42) leads to adaptive activation of microglia, as evidenced by increased co-localization of MHC class II with Abeta. To assess their antigen-presenting cell (APC) function, cultured microglia were pulsed with Abeta(1-42) in the presence of CD40L and co-cultured with CD4(+) T cells. Under these conditions, microglia stimulate T cell-derived IFN-gamma and IL-2 production, suggesting that CD40 signaling promotes the APC phenotype. These data provide a mechanistic explanation for our previous work showing decreased microgliosis associated with diminished cerebral Abeta/beta-amyloid pathology when blocking CD40 signaling in transgenic Alzheimer's mice.