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Epigallocatechin-3-gallate (EGCG) is a candidate for treatment of Alzheimer's disease (AD) but its inherent instability limits bioavailability and effectiveness. We found that EGCG displayed increased stability when formulated as dualdrug loaded PEGylated PLGA nanoparticles (EGCG/AA NPs). Oral administration of EGCG/AA NPs in mice resulted in EGCG accumulation in all major organs, including the brain. Pharmacokinetic comparison of plasma and brain accumulation following oral administration of free or EGCG/AA NPs showed that, whilst in both cases initial EGCG concentrations were similar, long-term (5-25 h) concentrations were ca. 5 fold higher with EGCG/AA NPs. No evidence was found that EGCG/AA NPs utilised a specific pathway across the blood-brain barrier (BBB). However, EGCG, empty NPs and EGCG/AA NPs all induced tight junction disruption and opened the BBB in vitro and ex vivo. Oral treatment of APPswe/PS1dE9 (APP/PS1) mice, a familial model of AD, with EGCG/AA NPs resulted in a marked increase in synapses, as judged by synaptophysin (SYP) expression, and reduction of neuroinflammation as well as amyloid β (Aβ) plaque burden and cortical levels of soluble and insoluble Aβ(1-42) peptide. These morphological changes were accompanied by significantly enhanced spatial learning and memory. Mechanistically, we propose that stabilisation of EGCG in NPs complexes and a destabilized BBB led to higher therapeutic EGCG concentrations in the brain. Thus EGCG/AA NPs have the potential to be developed as a safe and strategy for the treatment of AD.

Although metabolic syndrome (MS) and systemic lupus erythematosus (SLE) are often associated, a common link has not been identified. Using the BWF1 mouse, which develops MS and SLE, we sought a molecular connection to explain the prevalence of these two diseases in the same individuals. We determined SLE- markers (plasma anti-ds-DNA antibodies, splenic regulatory T cells (Tregs) and cytokines, proteinuria and renal histology) and MS-markers (plasma glucose, non-esterified fatty acids, triglycerides, insulin and leptin, liver triglycerides, visceral adipose tissue, liver and adipose tissue expression of 86 insulin signaling-related genes) in 8-, 16-, 24-, and 36-week old BWF1 and control New-Zealand-White female mice. Up to week 16, BWF1 mice showed MS-markers (hyperleptinemia, hyperinsulinemia, fatty liver and visceral adipose tissue) that disappeared at week 36, when plasma anti-dsDNA antibodies, lupus nephritis and a pro-autoimmune cytokine profile were detected. BWF1 mice had hyperleptinemia and high splenic Tregs till week 16, thereby pointing to leptin resistance, as confirmed by the lack of increased liver P-Tyr-STAT-3. Hyperinsulinemia was associated with a down-regulation of insulin related-genes only in adipose tissue, whereas expression of liver mammalian target of rapamicyn (mTOR) was increased. Although leptin resistance presented early in BWF1 mice can slow-down the progression of autoimmunity, our results suggest that sustained insulin stimulation of organs, such as liver and probably kidneys, facilitates the over-expression and activity of mTOR and the development of SLE.

[cat] Nombroses evidències mostren l'important paper dels receptors nuclears PPAR en el control de l'homeòstasi energètica a través de les seves accions reguladores sobre el metabolisme lipídic i glucídic, a més de la seva implicació en processos inflamatoris, tumorals i en la reproducció i el desenvolupament embrionari. La falta de lligands específics de PPARβ/δ fins fa relativament poc ha fet que els efectes fisiològics d'aquest subtipus hagin estat poc estudiats en relació als altres subtipus de PPAR, PPARα i PPARγ. Actualment però, la disponibilitat d'agonistes selectius de PPARβ/δ com GW501516, ha ajudat a conèixer i entendre l'important paper fisiològic que juga aquest receptor com regulador de múltiples funcions cel·lulars, especialment en la regulació del metabolisme i la resposta inflamatòria. Encara, però, resta per determinar els mecanismes moleculars responsables d'aquets efectes provocats per l'administració d'aquests fàrmacs, ja que només han estat parcialment estudiats. Els objectius d'aquesta tesi doctoral han estat: 1. Establir els mecanismes responsables de l'efecte hipotrigliceremiant de l'agonista de PPARβ/δ GW501516 en ratolins alimentats amb una dieta rica en greixos (HFD). 2. Establir els mecanismes responsables pels quals l'activador de PPARβ/δ GW501516 és capaç d'inhibir la resposta inflamatòria en queratinòcits humans estimulats amb TNF-α. Respecte el primer objectiu els resultats obtinguts indiquen que l'agonista PPARβ/δ GW501516 podria reduir els nivells de triglicèrids en plasma en un model animal de hipertrigliceridèmia evitant la reducció de l'AMPK i activant la via PGC1-α-Lipin 1-PPARα. D'altra banda, respecte el segon objectiu els resultats també demostren que GW501516 pot evitar la inflamació induïda per TNF-α en queratinòcits humans reduint l'activació del factor de transcripció pro-inflamatori NF-κB per l'activació de l'AMPK i SIRT1., [eng] The effects of PPARβ/δ subtype and its role in the metabolic syndrome and the inflammatory diseases has been elucidated in the last years, in part, by the availability of PPARβ/δ agonist GW501516, althought the mechanism involved is still unkonwn. In this study we examined the effects of PPARβ/δ activator GW501516 on high-fat diet (HFD)-induced hypertriglyceridemia. Our results showed that the hipertrigliceridemia caused by the HFD was reduced by the drug treatment. Also the PPARβ/δ activation prevented the reduction in the AMPK-Lipin1-PGC-1α pathway caused by the HFD, leading to an increase in hepatic fatty acid oxidation. This effect, together with increased hepatic expression in VLDL-receptor might be responsible for the hypotriglyceridemic effect of GW501516. Moreover, the PPARβ/δ activation by GW501516 also prevented TNF-α-induced NF-κB activation in human HaCaT cells by reducing p65 acetylation through AMPK and SIRT1.

OBJECTIVE: The very low-density lipoprotein receptor (VLDLR) plays an important role in the development of hepatic steatosis. In this study, we investigated the role of Peroxisome Proliferator-Activated Receptor (PPAR)beta/delta and fibroblast growth factor 21 (FGF21) in hepatic VLDLR regulation. METHODS: Studies were conducted in wild-type and Pparbeta/delta-null mice, primary mouse hepatocytes, human Huh-7 hepatocytes, and liver biopsies from control subjects and patients with moderate and severe hepatic steatosis. RESULTS: Increased VLDLR levels were observed in liver of Pparbeta/delta-null mice and in Pparbeta/delta-knocked down mouse primary hepatocytes through mechanisms involving the heme-regulated eukaryotic translation initiation factor 2alpha (eIF2alpha) kinase (HRI), activating transcription factor (ATF) 4 and the oxidative stress-induced nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathways. Moreover, by using a neutralizing antibody against FGF21, Fgf21-null mice and by treating mice with recombinant FGF21, we show that FGF21 may protect against hepatic steatosis by attenuating endoplasmic reticulum (ER) stress-induced VLDLR upregulation. Finally, in liver biopsies from patients with moderate and severe hepatic steatosis, we observed an increase in VLDLR levels that was accompanied by a reduction in PPARbeta/delta mRNA abundance and DNA-binding activity compared with control subjects. CONCLUSIONS: Overall, these findings provide new mechanisms by which PPARbeta/delta and FGF21 regulate VLDLR levels and influence hepatic steatosis development.

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/67430, Diabetic cardiomyopathy is characterized by structural and functional alterations in the heart muscle of people with diabetes that finally lead to heart failure. Metabolic disturbances characterized by increased lipid oxidation, intramyocardial triglyceride accumulation and reduced glucose utilization have all been involved in the pathogenesis of diabetic cardiomyopathy. On the other hand, evidences arisen in the recent years point to a potential link between chronic low-grade inflammation in the heart and metabolic dysregulation. Interestingly, the progression of heart failure and cardiac hypertrophy usually entails the activation of pro-inflammatory pathways. Therefore, in this chapter we summarize novel insights into the crosstalk between inflammatory processes and metabolic dysregulation in the failing heart during diabetes.