Ángel Carazo

Mitochondrial regulation by melatonin And its metabolites

Our results show that melatonin and N-acetyl-5-methoxykynurenamine (aMK) physiologically regulate both the electron transport chain (ETC) and OXPHOS, increasing the electron transport and ATP synthesis by normal mitochondria. Melatonin also counteracts mitochondrial oxidative damage induced by t-butyl hydroperoxide, recovering glutathione levels and ATP production. However, the effects of melatonin not only depend of its antioxidant properties, since the indoleamine specifically interacts with complex I and IV of the ETC increasing their activity. Experiments in vivo showed that melatonin administration prevents sepsis-induced ETC damage decreasing the activity and expression of INOS and mtNOS, thus reducing intramitochondrial nitric oxide (NO) and peroxynitrite (ONOO-) levels. Consequently, mitochondrial ETC ad ATP production recovered to normal conditions. The presence of specific binding of melatonin in mitochondrial matrix led us to explore the genomic role of the indoleamine in these organelles. In vivo and in vitro experiments showed that administration of melatonin increased mtONA transcriptional activity of the subunits 1-3 of the complex IV. These effects correlated well with the effects of melatonin on complex IV activity. The data suggest a new rate for melatonin to regulate mitochondrial homeostasis. Due to the relationships between mitochondrial damage, aging and neurodegenerative diseases, the effects of melatonin here described further support its antiaging and neuroprotective properties.

Importance of Host Genetic Factors HLA and IL28B as Predictors of Response to Pegylated Interferon and Ribavirin

OBJECTIVES:Viral factors are considered the best predictors of response to treatment for chronic hepatitis C (CHC), but genetic factors are known to have an important role in this respect. This paper investigates the relationships among the host genetic factors HLA and IL28B, viral factors, and the outcome of combination therapy.METHODS:A multicenter retrospective cohort of 428 previously untreated CHC patients was treated with pegylated interferon/ribavirin (pegIFN/RBV) for 48 weeks. In all, 378 (88%) of these patients were genotype 1 or 4, and 50 (12%) were genotype 2 or 3.RESULTS:Multivariate logistic regression showed the rs12979860 CC genotype (adjusted odds ratio (aOR)=4.3, 95% confidence interval (95% CI): 2.6–7), the HLA-DQB1*0301 allele (aOR=2.08, 95% CI: 1.2–3.5) and age, viral genotype, and viral load levels to be significantly associated with sustained virological response (SVR). When the variable rs12979860 was eliminated, the area under the receiver operating characteristic (ROC) curve (AUC) decreased significantly (0.76 vs. 0.69; P=0.03). AUC values derived from viral factors were lower than those corresponding to host genetic factors (0.67 vs. 0.72, respectively; P=0.04). The HLA-DQB1*0301 and A*0201 alleles were associated with rs12979860 CC genotype and SVR (P<0.0001).CONCLUSIONS:The HLA-DQB1*0301 allele and IL28B genotype are factors that are associated independently with SVR. There is a synergism between the HLA-DQB1*0301 and HLA-A*0201 alleles with polymorphism rs12979860 CC, which increases the SVR rate. IL28B genotype is the best predictor of SVR.

Nanoengineering of doxorubicin delivery systems with functionalized maghemite nanoparticles

Superparamagnetic iron oxide nanoparticles are developing as promising candidates for biomedical applications such as targeted drug delivery. In particular, they represent an alternative to existing antitumor drug carriers, because of their ultra-fine size, low toxicity and magnetic characteristics. Nevertheless, there is a need to functionalize them in order to achieve good biocompatibility, efficient modification for further attachment of biomolecules, and improved stability. In this work we describe the functionalization of superparamagnetic maghemite nanoparticles encapsulated in a silica shell. After their chemical modification with positive (3-aminopropyl)trimethoxysilane, a gold layer was deposited in order to facilitate incorporation of the antitumor drug, doxorubicin (DOX), up to a maximum loading of 80 μmol/g. In vitro cell uptake of nanocomposites was performed with DLD-1 colon cancer cells and PLC-PRF-5 liver cancer cells. Confocal microscopy photos illustrate that doxorubicin-loaded nanoparticles accumulate in both the cytoplasm and the cell nuclei. Cell survival efficiency with maghemite nanocomposites was determined via the MTT assay, and the cytotoxicity study proved that they exhibited significant toxicity against both types of cancer cells, although the improvement over free DOX treatment is more evident in the case of DLD-1 cancer cells when the most dilute drug and particle solutions are compared.

Inhibition of poly (ADP-ribose) polymerase-1 enhances doxorubicin activity against liver cancer cells

The purpose of this study was to investigate whether PARP-1 inhibition sensitizes human liver cancer cell lines to doxorubicin treatment. Both the addition of PARP-1 inhibitor (ANI) and depletion by means of stable siRNA significantly enhanced the growth inhibition induced by the DNA damage agents used. This effect was associated with an accumulation of unrepaired DNA, with a reduction in EGFR and Bcl-xL gene expression as well as with positive annexin-V staining. These results provide novel evidence of the direct role of PARP-1 in tumour chemoresistance in relation to its effects on the transcription of key genes involved in tumour survival.

Changes in cultured arterial smooth muscle cells isolated from chicks upon cholesterol feeding.

We have developed cultures of smooth muscle cells (SMC) isolated from arterial hypercholesterolemic chicks (cholesterol-SMC). These cultures are suitable for the study at the molecular level of the changes in arterial SMC induced by a cholesterol diet. By using a strong dose of cholesterol (5%) for 10 d, we obtained very proliferative SMC which became foam cells after 30 d in culture. On the other hand, SMC cultures isolated from control-fed chicks has a lower growth rate than the SMC ones under the same culture conditions. DNA synthesis was fourfold greater in cholesterol-SMC than in control-SMC cultures. Intracellular cholesterol concentrations were the same in both cholesterol and control SMC during the first 14 d of culture but afterward increased in differing ways: after 20 d of culture the cholesterol-SMC increased their cholesterol content to double the control. We give here the results obtained from transmission electron microscopy, lipid analysis, proliferation studies, DNA, RNA and protein synthesis, and then discuss their implications.

Functionalized magnetic nanoparticles as vehicles for the delivery of the antitumor drug gemcitabine to tumor cells. Physicochemical in vitro evaluation

Gemcitabine is a chemotherapy drug used in different carcinomas, although because it displays a short biological half-life, its plasmatic levels can quickly drop below the effective threshold. Nanoparticle-based drug delivery systems can provide an alternative approach for regulating the bioavailability of this and most other anticancer drugs. In this work we describe a new model of composite nanoparticles consisting of a core of magnetite nanoparticles, coated with successive layers of high molecular weight poly(acrylic acid) and chitosan, and a final layer of folic acid. The possibility of using these self-assembled nanostructures for gemcitabine vehiculization is explored. First, the surface charge of the composite particles is studied by means of electrophoretic mobility measurements as a function of pH for poly(acrylic acid) (carbopol) of different molecular weights. The adsorption of folic acid, aimed at increasing the chances of the particles to pass the cell membrane, is followed up by optical absorbance measurements, which were also employed for drug adsorption determinations. As a main result, it is shown that gemcitabine adsorbs onto the surface of chitosan/carbopol-coated magnetite nanoparticles. In vitro experiments show that the functionalized magnetic nanoparticles are able to deliver the drug to the nuclei of liver, colon and breast tumor cells.

Hepatic Expression of Adiponectin Receptors Increases with Non-alcoholic Fatty Liver Disease Progression in Morbid Obesity in Correlation with Glutathione Peroxidase 1

BackgroundThe prevalence of non-alcoholic fatty liver disease (NAFLD) in obesity is very high. The role of adiponectin receptors in NAFLD progression remains still unclear. We speculate that changes in the hepatic expression levels of the two adiponectin receptors may be associated with the expression of oxidative stress-related genes.MethodsWe studied 60 morbidly obese patients with NAFLD, who underwent liver biopsy at the time of bariatric surgery. We measured the hepatic messenger-RNA concentration of adiponectin receptors (ADIPOR1 and ADIPOR2), glutathione peroxidase 1 (GPx1), glutathione reductase (GRd) and inducible oxide nitric synthase. Additionally, biochemical parameters and oxidative stress markers were determined in blood samples. According to the Kleiner score, the patients were divided into two groups: group 1 (25 patients without steatohepatitis) and group 2 (25 patients with probable steatohepatitis and ten patients with steatohepatitis).ResultsThe messenger-RNA concentration of all genes analysed in the study was higher among the patients in group 2. However, no differences in blood oxidative stress markers were observed. Strong correlations were found among the expression levels of ADIPOR1, ADIPOR2 and GPx1. The multivariate analysis showed that the only independent variable associated with NAFLD progression was the increase in GPx1 expression levels.ConclusionsNAFLD progression in morbid obesity is associated with increase in hepatic adiponectin receptor and oxidative stress-related genes. The linear correlations suggest that ADIPOR1, ADIPOR2 and GPx1 share key molecular factors in the regulation of the genetic expressions.

Importance of IL-10 and IL-6 during chronic hepatitis C genotype-1 treatment and their relation with IL28B.

UNLABELLED This paper investigates serum levels of interleukin 10 (IL-10) and interleukin 6 (IL-6) in patients with chronic hepatitis C genotype 1 (CHC-GT1), the relation of each with clinical and virological characteristics, how they affect the response to combined therapy and their relation with the IL28B polymorphisms rs12979860. Serum level expression and the polymorphism of IL-10, IL-6 and IL28B were determined in 138 CHC-GT1 patients, treated with pegylated interferon/ribavirin (pegIFN-α/RBV) for 48 weeks, in the following samples: baseline, week-12 (during treatment) and week-72 (post-treatment). 77 patients (56%) presented Sustained Virological Response (SVR) and 61 (44%) were non-SVR. Multivariate logistic regression showed that age ≤ 40 years (aOR=3.7, 95%CI=1.5-8.9, P=0.004), low activity of gamma glutamyl transferase (GGT) (aOR=0.9, 95%CI=0.98-0.99, P=0.028), CC genotype of IL28B polymorphism (aOR=2.7, 95%CI=1.0-7.2, P=0.044) and low IL-6 (aOR=0.5, 95%CI=0.3-1.0, P=0.038) were predictor factors of virological response. In all patients, following treatment, IL-6 decreased at week-12 (P=0.004) from baseline and had returned to basal values at week-72. Serum IL-10 concentration was significantly decreased at week-72 only in SVR patients (P ≤ 0.001). When patients were stratified by IL28B polymorphisms rs12979860 CC vs non-CC patients, a statistically significant decrease in IL-10 at week-72 in both groups was observed (P=0.003 and P ≤ 0.001, respectively). None of the polymorphisms of IL-10 or IL-6 studied were associated with SVR. CONCLUSIONS CC genotype of IL28B and low IL-6 serum concentration are factors associated independently with SVR. Moreover, decreased IL-10 at week-72 is associated with SVR in both CC and non-CC patients, and both factors are important to determine the effectiveness of treatment.

Gender-related invasion differences associated with mRNA expression levels of melatonin membrane receptors in colorectal cancer

Melatonin inhibits growth and invasive capacity of colon cancer cells in vitro through its membrane (MT1 and MT2) and/or nuclear receptors (RORα). Previous studies showed that this indoleamine is present in both the normal and colon cancer at similar levels. Therefore, we analyzed MT1, MT2, and RORα expression in tumor samples versus normal mucosa (NM) from patients suffering from colorectal cancer (CRC). Given the existence of sex differences in the incidence and pathology of CRC and the involvement of steroid receptors in the oncostatic actions of melatonin in some types of cancer, we also analyzed the expression of androgen (AR) and estrogen receptor (ER) α and ERβ. Finally, we conducted some experiments in colon cancer cell lines to corroborate the experiments carried out in human tumors. We found a decreased expression of MT1, MT2, AR, ERα, and ERβ in tumor samples versus NM, but no changes in RORα expression in the whole cohort of patients. Classifying tumors by stage and gender, MT1, MT2, AR, ERα, and ERβ expression decreased in both early stage and advanced tumors, but only in male patients. On the other hand, MT1 and MT2 expression correlated positively with AR, ERα, and ERβ expression in male patients and with ERα or ERβ in female patients. In vitro, the invasive capacity was higher in cells with the least expression of MT1, MT2, and AR, and nonselective MT1/MT2 agonists inhibited cell growth and invasion. These results could indicate a possible interaction of these pathways.

Variation of Transaminases, HCV-RNA Levels and Th1/Th2 Cytokine Production during the Post-Partum Period in Pregnant Women with Chronic Hepatitis C

This study analyses the evolution of liver disease in women with chronic hepatitis C during the third trimester of pregnancy and the post-partum period, as a natural model of immune modulation and reconstitution. Of the 122 mothers recruited to this study, 89 were HCV-RNA+ve/HIV-ve and 33 were HCV-RNA-ve/HIV-ve/HCVantibody+ve and all were tested during the third trimester of pregnancy, at delivery and post-delivery. The HCV-RNA+ve mothers were categorized as either Type-A (66%), with an increase in ALT levels in the post-partum period (>40 U/L; P<0.001) or as Type-B (34%), with no variation in ALT values. The Type-A mothers also presented a significant decrease in serum HCV-RNA levels in the post-delivery period (P<0.001) and this event was concomitant with an increase in Th1 cytokine levels (INFγ, P = 0.04; IL12, P = 0.01 and IL2, P = 0.01). On the other hand, the Type-B mothers and the HCV-RNA-ve women presented no variations in either of these parameters. However, they did present higher Th1 cytokine levels in the partum period (INFγ and IL2, P<0.05) than both the Type-A and the HCV-RNA-ve women. Cytokine levels at the moment of delivery do not constitute a risk factor associated with HCV vertical transmission. It is concluded that differences in the ALT and HCV-RNA values observed in HCV-RNA+ve women in the postpartum period might be due to different ratios of Th1 cytokine production. In the Type-B women, the high partum levels of Th1 cytokines and the absence of post-partum variation in ALT and HCV-RNA levels may be related to permanent Th1 cytokine stimulation.