Long-Lasting Immune Responses 4 Years after GAD-Alum Treatment in Children with Type 1 Diabetes

A phase II clinical trial with glutamic acid decarboxylase (GAD) 65 formulated with aluminium hydroxide (GAD-alum) has shown efficacy in preserving residual insulin secretion in children and adolescents with recent-onset type 1 diabetes (T1D). We have performed a 4-year follow-up study of 59 of the original 70 patients to investigate long-term cellular and humoral immune responses after GAD-alum-treatment. Peripheral blood mononuclear cells (PBMC) were stimulated in vitro with GAD65. Frequencies of naïve, central and effector memory CD4+ and CD8+ T cells were measured, together with cytokine secretion, proliferation, gene expression and serum GAD65 autoantibody (GADA) levels. We here show that GAD-alum-treated patients display increased memory T-cell frequencies and prompt T-cell activation upon in vitro stimulation with GAD65, but not with control antigens, compared with placebo subjects. GAD65-induced T-cell activation was accompanied by secretion of T helper (Th) 1, Th2 and T regulatory cytokines and by induction of T-cell inhibitory pathways. Moreover, post-treatment serum GADA titres remained persistently increased in the GAD-alum arm, but did not inhibit GAD65 enzymatic activity. In conclusion, memory T- and B-cell responses persist 4 years after GAD-alum-treatment. In parallel to a GAD65-induced T-cell activation, our results show induction of T-cell inhibitory pathways important for regulating the GAD65 immunity

The fraction of activated N-methyl-d-Aspartate receptors during synaptic transmission remains constant in the presence of the glutamate release inhibitor riluzole

Excessive N-methyl-d-aspartate (NMDA) receptor activation is widely accepted to mediate calcium-dependent glutamate excitotoxicity. The uncompetitive, voltage-dependent NMDA receptor antagonist memantine has been successfully used clinically in the treatment of neurodegenerative dementia and is internationally registered for the treatment of moderate to severe Alzheimer′s disease. Glutamate release inhibitors (GRIs) may also be promising for the therapy of some neurodegenerative diseases. During the clinical use of GRIs, it could be questioned whether there would still be a sufficient number of active NMDA receptors to allow any additional effects of memantine or similar NMDA receptor antagonists. To address this question, we determined the fraction of NMDA receptors contributing to postsynaptic events in the presence of therapeutically relevant concentrations of the GRI riluzole (1 μM) using an in vitro hippocampal slice preparation. We measured the charge transfer of pharmacologically isolated excitatory synaptic responses before and after the application of the selective, competitive NMDA receptor antagonist D-AP5 (100 μM). The fraction of activated NMDA receptors under control conditions did not differ from those in the presence of riluzole. It is therefore likely that NMDA receptor antagonists would be able to exert additional therapeutic effects in combination therapy with GRIs

Dichotomy of Tyrosine Hydroxylase and Dopamine Regulation between Somatodendritic and Terminal Field Areas of Nigrostriatal and Mesoaccumbens Pathways

Measures of dopamine-regulating proteins in somatodendritic regions are often used only as static indicators of neuron viability, overlooking the possible impact of somatodendritic dopamine (DA) signaling on behavior and the potential autonomy of DA regulation between somatodendritic and terminal field compartments. DA reuptake capacity is less in somatodendritic regions, possibly placing a greater burden on de novo DA biosynthesis within this compartment to maintain DA signaling. Therefore, regulation of tyrosine hydroxylase (TH) activity may be particularly critical for somatodendritic DA signaling. Phosphorylation of TH at ser31 or ser40 can increase activity, but their impact on L-DOPA biosynthesis in vivo is unknown. Thus, determining their relationship with L-DOPA tissue content could reveal a mechanism by which DA signaling is normally maintained. In Brown-Norway Fischer 344 F1 hybrid rats, we quantified TH phosphorylation versus L-DOPA accumulation. After inhibition of aromatic acid decarboxylase, L-DOPA tissue content per recovered TH protein was greatest in NAc, matched by differences in ser31, but not ser40, phosphorylation. The L-DOPA per catecholamine and DA turnover ratios were significantly greater in SN and VTA, suggesting greater reliance on de novo DA biosynthesis therein. These compartmental differences reflected an overall autonomy of DA regulation, as seen by decreased DA content in SN and VTA, but not in striatum or NAc, following short-term DA biosynthesis inhibition from local infusion of the TH inhibitor α-methyl-p-tyrosine, as well as in the long-term process of aging. Such data suggest ser31 phosphorylation plays a significant role in regulating TH activity in vivo, particularly in somatodendritic regions, which may have a greater reliance on de novo DA biosynthesis. Thus, to the extent that somatodendritic DA release affects behavior, TH regulation in the midbrain may be critical for DA bioavailability to influence behavior

Excitatory amino acidergic pathways and receptors in the basal ganglia

The striatum receives the majority of excitatory amino acidergic input to the basal ganglia from neocortical and allocortical sources. The subthalamic nucleus and the substantia nigra also receive excitatory amino acidergic inputs from neocortex. The subthalamic nucleus, which has prominent projections to the pallidum and nigra, is the only known intrinsic excitatory amino acidergic component of the basal ganglia. Possible excitatory amino acidergic inputs reach the basal ganglia from the intralaminar thalamic nuclei and the pedunculo-pontine nucleus. The striatum is richly endowed with all subtypes of excitatory amino acid receptors and these appear to be inhomogeneously distributed within the striatal complex. The non-striatal nuclei contain lesser levels of excitatory amino acid receptors and the relative proportion of these receptors varies between nuclei. The presence of high densities of excitatory amino acid receptors is a phylogenetically conserved feature of the striatum and its non-mammalian homologues. In Huntington's disease, there is substantial depletion of α -amino-3-hydroxy-5-methylisoxazole-4-propionic acid, N-methyl-D-aspartate, and kainate receptors within the striatum. In Parkinson's disease substantia nigra, there is significant loss of N-methyl-D-aspartate and α -amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41734/1/726_2004_Article_BF00814003.pd

Thin micro-cold plate for hot-spot aware chip cooling

International audienc

RF characterization of the substrate coupling noise between TSV and active devices in 3D integrated circuits

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