Daily patterns of clock and cognition-related factors are modified in the hippocampus of vitamin A-deficient rats

The circadian expression of clock and clock-controlled cognition-related genes in the hippocampus would be essential to achieve an optimal daily cognitive performance. There is some evidence that retinoid nuclear receptors (RARs and RXRs) can regulate circadian gene expression in different tissues. In this study, Holtzman male rats from control and vitamin A-deficient groups were sacrificed throughout a 24-h period and hippocampus samples were isolated every 4 or 5 h. RARα and RXRβ expression level was quantified and daily expression patterns of clock BMAL1, PER1, RORα, and REVERB genes, RORα and REVERB proteins, as well as temporal expression of cognition-related RC3 and BDNF genes were determined in the hippocampus of the two groups of rats. Our results show significant daily variations of BMAL1, PER1, RORα, and REVERB genes, RORα and REVERB proteins and, consequently, daily oscillating expression of RC3 and BDNF genes in the rat hippocampus. Vitamin A deficiency reduced RXRβ mRNA level as well as the amplitude of PER1, REVERB gene, and REVERB protein rhythms, and phase-shifted the daily peaks of BMAL1 and RORα mRNA, RORα protein, and RC3 and BDNF mRNA levels. Thus, nutritional factors, such as vitamin A and its derivatives the retinoids, might modulate daily patterns of BDNF and RC3 expression in the hippocampus, and they could be essential to maintain an optimal daily performance at molecular level in this learning-and-memory-related brain area.     

Induction of multi-functional T cells in a phase I clinical trial of dendritic cell immunotherapy in hepatitis C virus infected individuals

We have previously reported a world-first phase I clinical trial to treat HCV patients using monocyte-derived dendritic cells (Mo-DC) loaded with HCV-specific lipopeptides. While the brief treatment proved to be safe, it failed to reduce the viral load and induced only transient cell-mediated immune responses, measured by IFNγ ELIspot. Here we reanalysed the PBMC samples from this trial to further elucidate the immunological events associated with the Mo-DC therapy. We found that HCV-specific single- and multi-cytokine secreting T cells were induced by the Mo-DC immunotherapy in some patients, although at irregular intervals and not consistently directed to the same HCV antigen. Despite the vaccination, the responses were generally poor in quality and comprised of primarily single-cytokine secreting cells. The frequency of FOXP3(+) regulatory T cells (Treg) fluctuated following DC infusion and eventually dropped to below baseline by week 12, an interesting trend suggesting that the vaccination may have resulted in a more subtle outcome than was initially apparent. Our data suggested that Mo-DC therapy induced complex immune responses in vivo that may or may not lead to clinical benefit.     

Improved immune response to recombinant influenza nucleoprotein formulated with ISCOMATRIX

Current influenza vaccines elicit antibodies effective against homologous strains, but new strategies are urgently needed for protection against emerging epidemic or pandemic strains. Although influenza vaccine candidates based on the viral nucleoprotein (NP) or matrix protein do not elicit sterilizing immunity, they have the advantage of inducing immunity that may cover a larger number of viral strains. In this study, recombinant NP produced in Escherichia coli was purified and formulated in combination with the adjuvant ISCOMATRIX. This formulation increased a NP-specific immunity in mice, with a Th1 profile, and may constitute a promising low-cost influenza vaccine candidate, with ability to stimulate humoral and cellular immune responses..     

The rostral micro-tooth morphology of blue marlin,Makaira nigricans

Billfish rostra potentially have several functions; however, their role in feeding is unequivocal in some species. Recent work linked morphological variation in rostral micro-teeth to differences in feeding behavior in two billfish species, the striped marlin (Kajikia audax) and the sailfish (Istiophorus platypterus). Here, we present the rostral micro-tooth morphology for a third billfish species, the blue marlin (Makaira nigricans), for which the use of the rostrum in feeding behavior is still undocumented from systematic observations in the wild. We measured the micro-teeth on rostrum tips of blue marlin, striped marlin, and sailfish using a micro–computed tomography approach and compared the tooth morphology among the three species. This was done after an analysis of video-recorded hunting behavior of striped marlin and sailfish revealed that both species strike prey predominantly with the first third of the rostrum, which provided the justification to focus our analysis on the rostrum tips. In blue marlin, intact micro-teeth were longer compared to striped marlin but not to sailfish. Blue marlin had a higher fraction of broken teeth than both striped marlin and sailfish, and broken teeth were distributed more evenly on the rostrum. Micro-tooth regrowth was equally low in both marlin species but higher in sailfish. Based on the differences and similarities in the micro-tooth morphology between the billfish species, we discuss potential feeding-related rostrum use in blue marlin. We put forward the hypothesis that blue marlin might use their rostra in high-speed dashes as observed in striped marlin, rather than in the high-precision rostral strikes described for sailfish, possibly focusing on larger prey organisms.     

Melatonin protects against taurolithocholic‐induced oxidative stress in rat liver

Cholestasis, encountered in a variety of clinical disorders, is characterized by intracellular accumulation of toxic bile acids in the liver. Furthermore, oxidative stress plays an important role in the pathogenesis of bile acids. Taurolithocholic acid (TLC) was revealed in previous studies as the most pro‐oxidative bile acid. Melatonin, a well‐known antioxidant, is a safe and widely used therapeutic agent. Herein, we investigated the hepatoprotective role of melatonin on lipid and protein oxidation induced by TLC alone and in combination with FeCl₃ and ascorbic acid in rat liver homogenates and hepatic membranes. The lipid peroxidation products, malondialdehyde and 4‐hydroxyalkenals (MDA + 4‐HDA), and carbonyl levels were quantified as indices of oxidative damage to hepatic lipids and proteins, respectively. In the current study, the rise in MDA + 4‐HDA levels induced by TLC was inhibited by melatonin in a concentration‐dependent manner in both liver homogenates and in hepatic membranes. Melatonin also had protective effects against structural damage to proteins induced by TLC in membranes. These results suggest that the indoleamine melatonin may potentially act as a protective agent in the therapy of those diseases that involve bile acid toxicity. J. Cell. Biochem. 110: 1219–1225, 2010. Published 2010 Wiley‐Liss, Inc.     

Functional Characterization of TLR4 +3725 G/C Polymorphism and Association with Protection against Overweight

Subclinical low-grade systemic inflammation has been associated with obesity, insulin resistance and metabolic syndrome (MS). Recent studies have highlighted the role of gut microbiota in these disorders. The toll-like receptor 4 (TLR4) plays a key role in the innate immune response activation. We studied two polymorphisms (+3725G/C and 11350G/C) in the 3′ untranslated region (3′UTR) of the TLR4 gene that may alter its expression and their association with metabolic disorders related to systemic inflammation. We cloned the 3′UTR into a luciferase reporter system and compared wild-type 3′UTR (WT) and +3725C variant (MUT) constructs luciferase activities. MUT construct reduced the reporter gene activity by 30% compared to WT (P = 0.0001). To evaluate the association between these polymorphisms with biochemical and clinical overweight related variables, we conducted a population cross-sectional study in 966 men of Argentine general population. Considering smoking as a confounding variable that causes systemic inflammation, we studied these possible effects in both, smokers and nonsmokers. The 11350G/C polymorphism was not detected in our sample whereas the CC genotype of +3725 polymorphism was associated with lean subjects (p = 0.011) and higher Adiponectin levels (p = 0.021). Subjects without any NCEP/ATP III MS component were associated with this genotype as well (p = 0.001). These results were strengthened in nonsmokers, in which CC genotype was associated with lean subjects (p = 0.003) and compared with G carriers showed significantly lower BMI (25.53 vs. 28.60 kg/m2; p = 0.023) and waist circumference (89.27 vs. 97.51 cm; p = 0.025). None of these associations were found in smokers. These results showed that +3725C variant has a functional effect down-regulating gene expression and it could be considered as a predictive factor against overweight, particularly in nonsmokers. Considering the role of TLR4 in inflammation, these findings would suggest that the presence of +3725C variant could predict a lower prevalence of chronic metabolic disorders.     

Hypersaline waters - a potential source of foodborne toxigenic aspergilli and penicillia

Previous studies of hypersaline environments have revealed the dominant presence of melanized yeast-like fungi and related Cladosporium spp. In this study, we focused on the genera Aspergillus and Penicillium and their teleomorphic forms. From oligotrophic and eutrophic hypersaline waters around the world, 60 different species were identified, according to their morphological characteristics and extrolite profiles. For the confirmation of five new species, additionally, sequence analysis of the internal transcribed spacer region, the partial large subunit-rDNA and the partial β-tubulin gene was performed. The species Aspergillus niger, Eurotium amstelodami and Penicillium chrysogenum were detected with the highest frequencies at all of the sampled sites; thus, they represent the pan-global stable mycobiota in hypersaline environments. Possible candidates were also Aspergillus sydowii and Eurotium herbariorum, as they were quite evenly distributed among the sampled sites, and Aspergillus candidus, which was abundant, but more locally distributed. These species and their byproducts can accumulate downstream following evaporation of brine, and they can become entrapped in the salt crystals. Consequently, marine salt used for consumption can be a potential source of food-borne fungi and their byproducts. For example, ochratoxin-A-producing species Penicillium nordicum was recovered from brine, salt and salted meat products.     

Increased urinary glucocorticoid metabolites are associated with metabolic syndrome, hypoadiponectinemia, insulin resistance and β cell dysfunction

Metabolic syndrome (MetS) may have increased cortisol (F) production caused by 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in liver and adipose tissue and/or by HPA axis dysregulation. F is then mainly metabolized by liver reductases into inactive tetrahydrometabolites (THMs). We measured THM levels in patients with or without MetS and evaluate the correlation between THMs and anthropometric and biochemical parameters. We recruited 221 subjects, of whom 130 had MetS by ATP III. We evaluated F, cortisone (E), adipokines, glucose, insulin and lipid profiles as well as urinary (24 h) F, E and THM levels. β Cell function was estimated by the HOMA Calculator. We observed that patients with MetS showed higher levels of THMs, HOMA-IR and leptin and lower levels of adiponectin and HOMA-β but no differences in F and E in plasma or urine. THM was associated with weight (r = +0.44, p < 0.001), waist circumference (r = +0.38, p < 0.01), glycemia (r = +0.37, p < 0.01), and triglycerides (r = +0.18, p = 0.06) and negatively correlated with adiponectin (r = −0.36, p < 0.001), HOMA-β (r = −0.21, p < 0.001) and HDL (r = −0.29, p < 0.01). In a logistic regression model, THM levels were associated with hypertension, hyperglycemia and dyslipidemia. We conclude that MetS is associated with increased urinary THMs but not with F and E levels in plasma or urine. Increased levels of THM, reflecting the daily cortisol production subsequently metabolized, are correlated with hypoadiponectinemia, hypertension, dyslipidemia, insulin resistance and β cell dysfunction. A subtle increased in glucocorticoid production may further account for the phenotypic and biochemical similarities observed in central obesity and Cushing’s syndrome.