Reduced plaque size and inflammation in the APP23 mouse model for Alzheimer's disease after chronic application of polymeric nanoparticles for CNS targeted zinc delivery.

A local dyshomeostasis of zinc ions in the vicinity of amyloid aggregates has been proposed in Alzheimer's disease (AD) due to the sequestration of zinc in senile plaques. While an increase in zinc levels may promote the aggregation of amyloid beta (Aß), increased brain zinc might also be beneficial rescuing some pathological alterations caused by local zinc deficiency. For example, increased Aß degradation by metalloproteinases, and a reduction in inflammation can be hypothesized. In addition, zinc may allow a stabilization of the number of synapses in AD brains. Thus, to evaluate whether altering zinc-levels within the brain is a promising new target for the prevention and treatment of AD, we employed novel zinc loaded nanoparticles able to deliver zinc into the brain across the blood-brain barrier. We performed in vivo studies using wild type (WT) and APP23 mice to assess plaque load, inflammatory status and synapse loss. Furthermore, we performed behavioral analyses. After chronically injecting these nanoparticles for 14 days, our results show a significant reduction in plaque size and effects on the pro-inflammatory cytokines IL-6 and IL-18. On behavioral level we could not detect negative effects of increased brain zinc levels in APP23 mice and treatment with g7-NP-Zn normalized the observed hyperlocomotion of APP23 mice. Therefore, we conclude that a targeted increase in brain zinc levels may have beneficial effects in AD.

"Heart-cut" bidimensional achiral-chiral liquid chromatography applied to the evaluation of stereoselective metabolism, in vivo biological activity and brain response to chiral drug candidates targeting the central nervous system.

A "heart-cut" two-dimensional achiral-chiral liquid chromatography triple-quadrupole mass spectrometry method (LC-LC-MS/MS) was developed and coupled to in vivo cerebral microdialysis to evaluate the brain response to the chiral compound (±)-7-chloro-5-(3-furanyl)-3-methyl-3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide ((±)-1), a potent positive allosteric modulator (PAM) of AMPA receptor. The method was successfully employed to evaluate also its stereoselective metabolism and in vitro biological activity. In particular, the LC achiral method developed, employs a pentafluorinated silica based column (Discovery HS-F5) to separate dopamine, acetylcholine, serotonin, (±)-1 and its two hepatic metabolites. In the "heart-cut" two-dimension achiral-chiral configuration, (±)-1 and (±)-1-d4 eluted from the achiral column (1st dimension), were transferred to a polysaccharide-based chiral column (2nd dimension, Chiralcel OD-RH) by using an automatic six-port valve. Single enantiomers of (±)-1 were separated and detected using electrospray positive ionization mode and quantified in selected reaction monitoring mode. The method was validated and showed good performance in terms of linearity, accuracy and precision. The new method employed showed several possible applications in the evaluation of: (a) brain response to neuroactive compounds by measuring variations in the brain extracellular levels of selected neurotransmitters and other biomarkers; (b) blood brain barrier penetration of drug candidates by measuring the free concentration of the drug in selected brain areas; (c) the presence of drug metabolites in the brain extracellular fluid that could prove very useful during drug discovery; (d) a possible stereoselective metabolization or blood brain barrier stereoselective crossing of chiral drugs. Finally, compared to the methods reported in the literature, this technique avoids the necessity of euthanizing an animal at each time point to measure drug concentration in whole brain tissue and provides continuous monitoring of extracellular concentrations of single chiral drug enantiomers along with its metabolites in specific brain regions at each selected time point for a desired period by using a single animal.

7-Chloro-5-(furan-3-yl)-3-methyl-4H-benzo[e][1,2,4]thiadiazine 1,1-Dioxide as Positive Allosteric Modulator of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptor. The End of the Unsaturated-Inactive Paradigm?

5-Arylbenzothiadiazine type compounds acting as positive allosteric modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-PAMs) have received particular attention in the past decade for their nootropic activity and lack of the excitotoxic side effects of direct agonists. Recently, our research group has published the synthesis and biological activity of 7-chloro-5-(3-furanyl)-3-methyl-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (1), one of the most active benzothiadiazine-derived AMPA-PAMs in vitro to date. However, 1 exists as two stereolabile enantiomers, which rapidly racemize in physiological conditions, and only one isomer is responsible for the pharmacological activity. In the present work, experiments carried out with rat liver microsomes show that 1 is converted by hepatic cytochrome P450 to the corresponding unsaturated derivative 2 and to the corresponding pharmacologically inactive benzenesulfonamide 3. Surprisingly, patch-clamp experiments reveal that 2 displays an activity comparable to that of the parent compound. Molecular modeling studies were performed to rationalize these results. Furthermore, mice cerebral microdialysis studies suggest that 2 is able to cross the blood-brain barrier and increases acetylcholine and serotonin levels in the hippocampus. The experimental data disclose that the achiral hepatic metabolite 2 possesses the same pharmacological activity of its parent compound 1 but with an enhanced chemical and stereochemical stability, as well as an improved pharmacokinetic profile compared with 1.

Modern industrial and pharmacological applications of indigo dye and its derivatives--a review.

Plant sources, chemical properties, bioactivities, as well as the synthesis of indigo dye and its derivatives, are reviewed in this paper. These compounds were chosen because of their significant benefits and scope of application as both coloring agents in the textile industry and as pharmacologically active natural products. Their use in traditional chinese medicine (TCM) has directed the attention of European researchers and medical doctors alike. The preparation of indigoferous plants--Indigo naturalis is currently about to be introduced into the European Pharmacopoeia.