Alice Cristina Rodrigues

Short-term, moderate exercise is capable of inducing structural, BDNF-independent hippocampal plasticity.

Exercise is known to improve cognitive functions and to induce neuroprotection. In this study we used a short-term, moderate intensity treadmill exercise protocol to investigate the effects of exercise on usual markers of hippocampal synaptic and structural plasticity, such as synapsin I (SYN), synaptophysin (SYP), neurofilaments (NF), microtubule-associated protein 2 (MAP2), glutamate receptor subunits GluR1 and GluR2/3, brain-derived neurotrophic factor (BDNF) and glial fibrillary acidic protein (GFAP). Immunohistochemistry, Western blotting and real-time PCR were used. We also evaluated the number of cells positive for the proliferation marker 5-bromo-2-deoxyuridine (BrdU), the neurogenesis marker doublecortin (DCX) and the plasma corticosterone levels. Adult male Wistar rats were adapted to a treadmill and divided into 4 groups: sedentary (SED), 3-day exercise (EX3), 7-day exercise (EX7) and 15-day exercise (EX15). The protein changes detected were increased levels of NF68 and MAP2 at EX3, of SYN at EX7 and of GFAP at EX15, accompanied by a decreased level of GluR1 at EX3. Immunohistochemical findings revealed a similar pattern of changes. The real-time PCR analysis disclosed only an increase of MAP2 mRNA at EX7. We also observed an increased number of BrdU-positive cells and DCX-positive cells in the subgranular zone of the dentate gyrus at all time points and increased corticosterone levels at EX3 and EX7. These results reveal a positive effect of short-term, moderate treadmill exercise on hippocampal plasticity. This effect was in general independent of transcriptional processes and of BDNF upregulation, and occurred even in the presence of increased corticosterone levels.

Molecular Targets Related to Inflammation and Insulin Resistance and Potential Interventions

Inflammation and insulin resistance are common in several chronic diseases, such as obesity, type 2 diabetes mellitus, metabolic syndrome, cancer, and cardiovascular diseases. Various studies show a relationship between these two factors, although the mechanisms involved are not completely understood yet. Here, we discuss the molecular basis of insulin resistance and inflammation and the molecular aspects on inflammatory pathways interfering in insulin action. Moreover, we explore interventions based on molecular targets for preventing or treating correlated disorders, advances for a better characterization, and understanding of the mechanisms and mediators involved in the different inflammatory and insulin resistance conditions. Finally, we address biotechnological studies for the development of new potential therapies and interventions.

High baseline serum total and LDL cholesterol levels are associated with MDR1 haplotypes in Brazilian hypercholesterolemic individuals of European descent

The MDR1 gene encodes the P-glycoprotein, an efflux transporter with broad substrate specificity. P-glycoprotein has raised great interest in pharmacogenetics because it transports a variety of structurally divergent drugs, including lipid-lowering drugs. The synonymous single-nucleotide polymorphism C3435T and the nonsynonymous single-nucleotide polymorphism G2677T/A in MDR1 have been indicated as potential determinants of variability in drug disposition and efficacy. In order to evaluate the effect of G2677T/A and C3435T MDR1 polymorphisms on serum levels of lipids before and after atorvastatin administration, 69 unrelated hypercholesterolemic individuals from São Paulo city, Brazil, were selected and treated with 10 mg atorvastatin orally once daily for four weeks. MDR1 polymorphisms were analyzed by PCR-RFLP. C3435T and G2677T polymorphisms were found to be linked. The allelic frequencies for C3435T polymorphism were 0.536 and 0.464 for the 3435C and 3435T alleles, respectively, while for G2677T/A polymorphism allele frequencies were 0.580 for the 2677G allele, 0.384 for the 2677T allele and 0.036 for the 2677A allele. There was no significant relation between atorvastatin response and MDR1 polymorphisms (repeated measures ANOVA; P > 0.05). However, haplotype analysis revealed an association between T/T carriers and higher basal serum total (TC) and LDL cholesterol levels (TC: 303 +/- 56, LDL-C: 216 +/- 57 mg/dl, respectively) compared with non-T/T carriers (TC: 278 +/- 28, LDL-C: 189 +/- 24 mg/dl; repeated measures ANOVA/Tukey test; P < 0.05). These data indicate that MDR1 polymorphism may have an important contribution to the control of basal serum cholesterol levels in Brazilian hypercholesterolemic individuals of European descent.

Efflux and uptake transporters as determinants of statin response

Importance of the field: The important role of drug transporters in drug absorption and disposition has been well documented. Statins are subjected to active transport of membrane proteins of the superfamilies ATP-binding cassette and solute carrier, and there is limited understanding of the mechanisms by which differences in transporter expression and activity contributes to variability of pharmacokinetics (PKs)/pharmacodynamics (PDs) of statins. Areas covered in this review: This review aims to discuss the roles of drug transporters in the PKs and PDs of statins, and in drug interactions with statins. What the reader will gain: A comprehensive summary of the literature on this subject including in vitro and in vivo observations. Take home message: In vivo and in vitro studies have shown that efflux and uptake transporters modulate the PKs/PDs of statins. Until now organic anion transporting polypeptides (OATP)1B1 variants have been considered major factors in limiting the uptake of statins and increasing statin exposure, and, consequently, increasing risk of myopathy. Further studies in pharmacogenetics and in vitro models to assess statin disposition and toxicity are required to understand the contribution of others transporters, such as multidrug resistance-associated protein (MRP)1, MRP2, breast cancer resistance protein, OATP2B1, OAT1B3 and OATP1A2, in interindividual variability to statins efficacy and safety.

Pharmacogenetics of OATP Transporters Reveals That SLCO1B1 c.388A>G Variant Is Determinant of Increased Atorvastatin Response

Aims The relationship between variants in SLCO1B1 and SLCO2B1 genes and lipid-lowering response to atorvastatin was investigated. Material and Methods One-hundred-thirty-six unrelated individuals with hypercholesterolemia were selected and treated with atorvastatin (10 mg/day/4 weeks). They were genotyped with a panel of ancestry informative markers for individual African component of ancestry (ACA) estimation by SNaPshot® and SLCO1B1 (c.388A>G, c.463C>A and c.521T>C) and SLCO2B1 (−71T>C) gene polymorphisms were identified by TaqMan® Real-time PCR. Results Subjects carrying SLCO1B1 c.388GG genotype exhibited significantly high low-density lipoprotein (LDL) cholesterol reduction relative to c.388AA+c.388AG carriers (41 vs. 37%, p = 0.034). Haplotype analysis revealed that homozygous of SLCO1B1*15 (c.521C and c.388G) variant had similar response to statin relative to heterozygous and non-carriers. A multivariate logistic regression analysis confirmed that c.388GG genotype was associated with higher LDL cholesterol reduction in the study population (OR: 3.2, CI95%:1.3–8.0, p < 0.05). Conclusion SLCO1B1 c.388A>G polymorphism causes significant increase in atorvastatin response and may be an important marker for predicting efficacy of lipid-lowering therapy.

CYP3A5*3A allele is associated with reduced lowering-lipid response to atorvastatin in individuals with hypercholesterolemia

BACKGROUND The cytochrome P450 isoenzyme 3A5 (CYP3A5) has an important role on biotransformation of xenobiotics. CYP3A5 SNPs have been associated with variations on enzyme activity that can modify the metabolism of several drugs. METHODS In order to evaluate the influence of CYP3A5 variants on response to lowering-cholesterol drugs, 139 individuals with hypercholesterolemia were selected. After a wash-out period of 4 weeks, individuals were treated with atorvastatin (10 mg/day/4 weeks). Genomic DNA was extracted by a salting-out procedure. CYP3A5*3C, CYP3A5*6 and CYP3A5*1D were analyzed by PCR-RFLP and DNA sequencing. RESULTS >Frequencies of the CYP3A5*3C and CYP3A5*1D alleles were lower in individuals of African descent (*3C: 47.8% and *1D: 55.2%) than in non-Africans (*3C: 84.9% and *1D 84.8%, p<0.01). Non-Africans carrying *3A allele (*3C and *1D combined alleles) had lower total and LDL-cholesterol response to atorvastatin than non-*3A allele carriers (p<0.05). CONCLUSION CYP3A5*3A allele is associated with reduced cholesterol-lowering response to atorvastatin in non-African individuals.

Moderate exercise changes synaptic and cytoskeletal proteins in motor regions of the rat brain.

Physical exercise is known to enhance brain function in several aspects. We evaluated the acute effects of a moderate forced exercise protocol on synaptic proteins, namely synapsin I (SYN) and synaptophysin (SYP), and structural proteins (neurofilaments, NFs) in rat brain regions related to motor function and often affected by neurodegenerative disorders. Immunohistochemistry, Western blotting and real-time PCR were used to analyze the expression of those proteins after 3, 7 and 15days of exercise (EX3, EX7 and EX15). In the cerebellum, increase of SYN was observed at EX7 and EX15 and of NF68 at EX3. In the substantia nigra, increases of protein levels were observed for NF68 and NF160 at EX3. In the striatum, there was an increase of SYN at EX3 and EX7, of SYP at EX7 and of NF68 at EX3. In the cortex, decreased levels of NF68 and NF160 were observed at EX3, followed by an increase of NF68 at EX15. In the reticular formation, all NF proteins were increased at EX15. The mRNA data for each time-point and region also revealed significant exercise-related changes of SYN, SYP and NF expression. These results suggest that moderate physical exercise modulates synaptic and structural proteins in motor brain areas, which may play an important role in the exercise-dependent brain plasticity.

The expression of efflux and uptake transporters are regulated by statins in Caco-2 and HepG2 cells

AbstractAim:Statin disposition and response are greatly determined by the activities of drug metabolizing enzymes and efflux/ uptake transporters. There is little information on the regulation of these proteins in human cells after statin therapy. In this study, the effects of atorvastatin and simvastatin on mRNA expression of efflux (ABCB1, ABCG2 and ABCC2) and uptake (SLCO1B1, SLCO2B1 and SLC22A1) drug transporters in Caco-2 and HepG2 cells were investigated.Methods:Quantitative real-time PCR was used to measure mRNA levels after exposure of HepG2 and Caco-2 cells to statins.Results:Differences in mRNA basal levels of the transporters were as follows: ABCC2>ABCG2>ABCB1>SLCO1B1>>>SLC22A1>SLC O2B1 for HepG2 cells, and SLCO2B1>>ABCC2>ABCB1>ABCG2>>>SLC22A1 for Caco-2 cells. While for HepG2 cells, ABCC2, ABCG2 and SLCO2B1 mRNA levels were significantly up-regulated at 1, 10 and 20 μmol/L after 12 or 24 h treatment, in Caco-2 cells, only the efflux transporter ABCB1 was significantly down-regulated by two-fold following a 12 h treatment with atorvastatin. Interestingly, whereas treatment with simvastatin had no effect on mRNA levels of the transporters in HepG2 cells, in Caco-2 cells the statin significantly down-regulated ABCB1, ABCC2, SLC22A1, and SLCO2B1 mRNA levels after 12 or 24 h treatment.Conclusion:These findings reveal that statins exhibits differential effects on mRNA expression of drug transporters, and this effect depends on the cell type. Furthermore, alterations in the expression levels of drug transporters in the liver and/or intestine may contribute to the variability in oral disposition of statins.

Fish oil supplementation for two generations increases insulin sensitivity in rats

We investigated the effect of fish oil supplementation for two consecutive generations on insulin sensitivity in rats. After the nursing period (21 days), female rats from the same prole were divided into two groups: (a) control group and (b) fish oil group. Female rats were supplemented with water (control) or fish oil at 1 g/kg body weight as a single bolus for 3 months. After this period, female rats were mated with male Wistar rats fed on a balanced chow diet (not supplemented). Female rats continued to receive supplementation throughout gestation and lactation periods. The same treatment was performed for the next two generations (G1 and G2). At 75 days of age, male offspring from G1 and G2 generations from both groups were used in the experiments. G1 rats did not present any difference with control rats. However, G2 rats presented reduction in glycemia and lipidemia and improvement in in vivo insulin sensitivity (model assessment of insulin resistance, insulin tolerance test) as well as in vitro insulin sensitivity in soleus muscle (glucose uptake and metabolism). This effect was associated with increased insulin-stimulated p38 MAP kinase phosphorylation and lower n-6/n-3 fatty acid ratio, but not with activation of proteins from insulin signaling (IR, IRS-1 and Akt). Global DNA methylation was decreased in liver but not in soleus muscle. These results suggest that long-term fish oil supplementation improves insulin sensitivity in association with increased insulin-stimulated p38 activation and decreased n-6:n-3 ratio in skeletal muscle and decreased global DNA methylation in liver.

Participation of neuronal nitric oxide synthase in experimental neuropathic pain induced by sciatic nerve transection

Nerve injury leads to a neuropathic pain state that results from central sensitization. This phenomenom is mediated by NMDA receptors and may involve the production of nitric oxide (NO). In this study, we investigated the expression of the neuronal isoform of NO synthase (nNOS) in the spinal cord of 3-month-old male, Wistar rats after sciatic nerve transection (SNT). Our attention was focused on the dorsal part of L3-L5 segments receiving sensory inputs from the sciatic nerve. SNT resulted in the development of neuropathic pain symptoms confirmed by evaluating mechanical hyperalgesia (Randall and Selitto test) and allodynia (von Frey hair test). Control animals did not present any alteration (sham-animals). The selective inhibitor of nNOS, 7-nitroindazole (0.2 and 2 microg in 50 microL), blocked hyperalgesia and allodynia induced by SNT. Immunohistochemical analysis showed that nNOS was increased (48% by day 30) in the lumbar spinal cord after SNT. This increase was observed near the central canal (Rexeds lamina X) and also in lamina I-IV of the dorsal horn. Real-time PCR results indicated an increase of nNOS mRNA detected from 1 to 30 days after SNT, with the highest increase observed 1 day after injury (1469%). Immunoblotting confirmed the increase of nNOS in the spinal cord between 1 and 15 days post-lesion (20%), reaching the greatest increase (60%) 30 days after surgery. The present findings demonstrate an increase of nNOS after peripheral nerve injury that may contribute to the increase of NO production observed after peripheral neuropathy.