New insight into the biological activity of Salmo salar NK-lysin antimicrobial peptides

NK-lysin is a potent antimicrobial peptide (AMP) with antimicrobial activity against bacteria, fungi, viruses, and parasites. NK-lysin is a type of granulysin, a member of the saposin-like proteins family first isolated from a pig's small intestine. In previous work, for the first time, we identified four variants of nk-lysin from Atlantic salmon (Salmo salar) using EST sequences. In the present study, we reported and characterized two additional transcripts of NK-lysin from S. salar. Besides, we evaluated the tissue distribution of three NK-lysins from S. salar and assessed the antimicrobial, hemolytic, and immunomodulatory activities and signaling pathways of three NK-lysin-derived peptides. The synthetic peptides displayed antimicrobial activity against Piscirickettsia salmonis (LF-89) and Flavobacterium psychrophilum. These peptides induced the expression of immune genes related to innate and adaptive immune responses in vitro and in vivo. The immunomodulatory activity of the peptides involves the mitogen-activated protein kinases-mediated signaling pathway, including p38, extracellular signal-regulated kinase 1/2, and/or c-Jun N-terminal kinases. Besides, the peptides modulated the immune response induced by pathogen-associated molecular patterns (PAMPs). Our findings show that NK-lysin could be a highly effective immunostimulant or vaccine adjuvant for use in fish aquaculture.

Design and functional characterization of Salmo salar TLR5 agonist peptides derived from high mobility group B1 acidic tail

Toll-like receptor 5 (TLR5) responds to the monomeric form of flagellin and induces the MyD88-depending signaling pathway, activating proinflammatory transcription factors such as NF-κB and the consequent induction of cytokines. On the other hand, HMGB1 is a highly conserved non-histone chromosomal protein shown to interact with and activate TLR5. The present work aimed to design and characterize TLR5 agonist peptides derived from the acidic tail of Salmo salar HMGB1 based on the structural knowledge of the TLR5 surface using global molecular docking platforms. Peptide binding poses complexed on TLR5 ectodomain model from each algorithm were filtrated based on docking scoring functions and predicted theoretical binding affinity of the complex. Circular dichroism spectra were recorded for each peptide selected for synthesis. Only intrinsically disordered peptides (6W, 11W, and SsOri) were selected for experimental functional assay. The functional characterization of the peptides was performed by NF-κB activation assays, RT-qPCR gene expression assays, and Piscirickettsia salmonis challenge in SHK-1 cells. The 6W and 11W peptides increased the nuclear translation of p65 and phosphorylation. In addition, the peptides induced the expression of genes related to the TLR5 pathway activation, pro- and anti-inflammatory response, and differentiation and activation of T lymphocytes towards phenotypes such as TH1, TH17, and TH2. Finally, it was shown that the 11W peptide protects immune cells against infection with P. salmonis bacteria. Overall, the results indicate the usefulness of novel peptides as potential immunostimulants in salmonids.

Agonistic effect of peptides derived from a truncated HMGB1 acidic tail sequence in TLR5 from Salmo salar

Based on the structural knowledge of TLR5 surface and using blind docking platforms, peptides derived from a truncated HMGB1 acidic tail from Salmo salar was designed as TLR5 agonistic. Additionally, a template peptide with the native N-terminal of the acidic tail sequence as a reference was included (SsOri). Peptide binding poses complexed on TLR5 ectodomain model from each algorithm were filtrated based on docking scoring functions and predicted theoretical binding affinity of the complex. The best peptides, termed 6WK and 5LWK, were selected for chemical synthesis and experimental functional assay. The agonist activity by immunoblotting and immunocytochemistry was determined following the NF-κBp65 phosphorylation (p-NF-κBp65) and the nuclear translocation of the NF-κBp65 subunit from the cytosol, respectively. HeLa cells stably expressing a S. salar TLR5 chimeric form (TLR5c7) showed increased p-NF-κBp65 levels regarding extracts from flagellin-treated cells. No statistically significant differences (p > 0.05) were found in the detected p-NF-κBp65 levels between cellular extracts treated with peptides or flagellin by one-way ANOVA. The image analysis of NF-κBp65 immunolabeled cells obtained by confocal microscopy showed increased nuclear NF-κBp65 co-localization in cells both 5LWK and flagellin stimulated, while 6WK and SsOri showed less effect on p65 nuclear translocation (p < 0.05). Also, an increased transcript expression profile of proinflammatory cytokines such as TNFα, IL-1β, and IL-8 in HKL cells isolated from Salmo salar was evidenced in 5LWK - stimulated by RT-PCR analysis. Overall, the result indicates the usefulness of novel peptides as a potential immunostimulant in S. salar.

New Formulation of a Subunit Vaccine Candidate against Lawsonia intracellularis Increases Humoral and Cellular Immune Responses

Previously, we designed a subunit vaccine candidate based on three L. intracellularis antigens with promising results in pigs. In this study, antigens were produced individually to achieve an even antigen ratio in the formulation. The emulsion characterization included the drop size and the mechanical and thermal stability. Immune response was evaluated by indirect and sandwich ELISAs, qPCR, and flow cytometry. The vaccine candidate's safety was assessed by histopathology and monitoring the clinical behavior of animals. The average production yielded for the chimeric antigen as inclusion bodies was around 75 mg/L. The formulation showed mechanical and thermal stability, with a ratio Hu/Ho > 0.85 and a drop size under 0.15 nm. Antigens formulated at a ratio of 1:1:1 induced a significant immune response in inoculated pigs that persisted until the end of the experiment (week 14). The dose of 200 μg significantly activated cellular response measured by transcriptional and translational levels of cytokines. The cell proliferation assay revealed an increment of lymphocytes T CD4+ at the same dose. Animals gained weight constantly and showed proper clinical behavior during immunization assays. This research demonstrated the immunological robustness of the new subunit vaccine candidate against Porcine Proliferative Enteropathy evenly formulated with three chimeric antigens of L. intracellularis.

Immunomodulatory role of vasoactive intestinal peptide and ghrelin in Oncorhynchus mykiss

Neuropeptides are a group of peptides derived from precursor proteins synthesized in neuronal and nonneuronal cells. The classical functions of neuropeptides have been extensively studied in mammals, including neuromodulation in the central nervous system, molecular signaling in the peripheral nervous system, and immunomodulation associated mainly with anti-inflammatory activity. In contrast, in teleosts, studies of the immunomodulatory function of these neuropeptides are limited. In Oncorhynchus mykiss, vasoactive intestinal peptide (VIP) mRNA sequences have not been cloned, and the role of VIP in modulating the immune system has not been studied. Furthermore, in relation to other neuropeptides with possible immunomodulatory function, such as ghrelin, there are also few studies. Therefore, in this work, we performed molecular cloning, identification, and phylogenetic analysis of three VIP precursor sequences (prepro-VIP1, VIP2 and VIP3) in rainbow trout. In addition, the immunomodulatory function of both neuropeptides was evaluated in an in vitro model using the VIP1 sequence identified in this work and a ghrelin sequence already studied in O. mykiss. The results suggest that the prepro-VIP2 sequence has the lowest percentage of identity with respect to the other homologous sequences and is more closely related to mammalian orthologous sequences. VIP1 induces significant expression of both pro-inflammatory (IFN-γ, IL-1β) and anti-inflammatory (IL-10 and TGF-β) cytokines, whereas ghrelin only induces significant expression of proinflammatory cytokines such as IL-6 and TNF-α.

Co-Formulation of Recombinant Porcine IL-18 Enhances the Onset of Immune Response in a New Lawsonia intracellularis Vaccine

Pig is one of the most consumed meats worldwide. One of the main conditions for pig production is Porcine Enteropathy caused by Lawsonia intracellularis. Among the effects of this disease is chronic mild diarrhea, which affects the weight gain of pigs, generating economic losses. Vaccines available to prevent this condition do not have the desired effect, but this limitation can be overcome using adjuvants. Pro-inflammatory cytokines, such as interleukin 18 (IL-18), can improve an immune response, reducing the immune window of protection. In this study, recombinant porcine IL-18 was produced and expressed in Escherichia coli and Pichia pastoris. The protein's biological activity was assessed in vitro and in vivo, and we determined that the P. pastoris protein had better immunostimulatory activity. A vaccine candidate against L. intracellularis, formulated with and without IL-18, was used to determine the pigs' cellular and humoral immune responses. Animals injected with the candidate vaccine co-formulated with IL-18 showed a significant increase of Th1 immune response markers and an earlier increase of antibodies than those vaccinated without the cytokine. This suggests that IL-18 acts as an immunostimulant and vaccine adjuvant to boost the immune response against the antigens, reducing the therapeutic window of recombinant protein-based vaccines.

Chitosan Microparticles Enhance the Intestinal Release and Immune Response of an Immune Stimulant Peptide in Oncorhynchus mykiss

The aquaculture industry is constantly increasing its fish production to provide enough products to maintain fish consumption worldwide. However, the increased production generates susceptibility to infectious diseases that cause losses of millions of dollars to the industry. Conventional treatments are based on antibiotics and antivirals to reduce the incidence of pathogens, but they have disadvantages, such as antibiotic resistance generation, antibiotic residues in fish, and environmental damage. Instead, functional foods with active compounds, especially antimicrobial peptides that allow the generation of prophylaxis against infections, provide an interesting alternative, but protection against gastric degradation is challenging. In this study, we evaluated a new immunomodulatory recombinant peptide, CATH-FLA, which is encapsulated in chitosan microparticles to avoid gastric degradation. The microparticles were prepared using a spray drying method. The peptide release from the microparticles was evaluated at gastric and intestinal pH, both in vitro and in vivo. Finally, the biological activity of the formulation was evaluated by measuring the expression of il-1β, il-8, ifn-γ, Ifn-α, and mx1 in the head kidney and intestinal tissues of rainbow trout (Oncorhynchus mykiss). The results showed that the chitosan microparticles protect the CATH-FLA recombinant peptide from gastric degradation, allowing its release in the intestinal portion of rainbow trout. The microparticle-protected CATH-FLA recombinant peptide increased the expression of il-1β, il-8, ifn-γ, ifn-α, and mx1 in the head kidney and intestine and improved the antiprotease activity in rainbow trout. These results suggest that the chitosan microparticle/CATH-FLA recombinant peptide could be a potential prophylactic alternative to conventional antibiotics for the treatment of infectious diseases in aquaculture.

First report of bovine viral diarrhea virus subgenotypes 1d and 1e in southern Chile

Bovine viral diarrhea virus (BVDV) affects cattle worldwide causing severe productive and economic loss. In this study, we investigated the subgenotypes of BVDV circulating in cattle samples from the Aysén region, an active cattle breeding area located in southern Chile. Partial amplification of the 5' untranslated region (UTR) was performed by polymerase chain reaction (PCR), and twelve samples were analyzed by Sanger sequencing and phylogenetic analysis. Eight samples were identified as belonging to Pestivirus bovis subgenotype 1e, three to 1-b, and one to 1-d. The phylogenetic analyses performed revealed a marked distance between these now-identified strains and those previously reported in the country. These findings support the need to continually expand the analysis of the variability of the viral phylogeny for the currently circulating BVDV strains and to update the vaccines recommended for this livestock area and surrounding areas.

Effects of recombinant FSH (bscrFSH) and pituitary FSH (FSH-p) on embryo production in superovulated dairy heifers inseminated with unsorted and sex-sorted semen

Superovulation is a drug-based method used in cattle to stimulate the ovarian folliculogenesis and the number of oocytes and transferable embryos. The present study aimed to test the effects of recombinant FSH (bscrFSH) and pituitary FSH (FSH-p) on ovarian response and in vivo embryo production in superovulated dairy heifers inseminated with unsorted and sex-sorted semen. Forty healthy Holstein heifers subjected to a superovulation (SOV) protocol by using FSH-p or bscrFSH were divided randomly into four groups: a) FSH-p inseminated with unsorted semen (USP; n = 10), b) FSH-p inseminated with sex-sorted semen (SSP; n = 10), c) bscrFSH inseminated with unsorted semen (USR; n = 10), and d) bscrFSH inseminated with sex-sorted semen (SSR; n = 10). Ultrasonography was carried out on Day 8 (estrus) and Day 15 (embryo collection) to evaluate the ovarian structures [follicles (FL), corpora lutea (CL), and non-ovulated follicles (NOFL)]. Embryonic-derived parameters were scored on Day 15 [total structures collected (TS), unfertilised oocytes (UFOs), total embryos (TEs), transferable embryos (TFEs), freezable embryos (FEs), and degenerated embryos (DEs)]. No differences were observed regarding ovarian structures (FL and NOFL) irrespective of SOV protocol or group assessed (P > 0.05). CL increased in bscrFSH-derived SOV protocol (P < 0.05). On Day 15, the embryonic-derived parameters TEs, TFEs, and FEs decreased in SSP/SSR compared to USP/USR (P < 0.05). Differences were observed regarding UFOs, with a greater number in SSP and SSR (P = 0.01). In conclusion, the bscrFSH-derived SOV protocol showed improved results compared to FSH-p-derived SOV protocol regarding ovarian (CL) and embryo-derived (TFE) parameters irrespective of the type of semen used.

Long-term release of bioactive interferon-alpha from PLGA-chitosan microparticles: in vitro and in vivo studies

Effective cytokine treatments often require high- and multiple-dose due to the short half-life of these molecules. Here, porcine interferon-alpha (IFNα) is encapsulated in PLGA-chitosan microparticles (IFNα-MPs) to accomplish both slow drug release and drug protection from degradation. A procedure that combines emulsion and spray-drying techniques yielded almost spherical microspheres with an average diameter of 3.00 ± 1.50 μm. SEM, Microtrac, and Z-potential analyses of three IFNα-MP batches showed similar results, indicating the process is reproducible. These studies supported molecular evidence obtained in FTIR analysis, which indicated a compact structure of IFNα-MPs. Consistently, IFNα release kinetics assessed in vitro followed a zero-order behavior typical of sustained release from a polymeric matrix. This study showed that IFNα-MPs released bioactive molecules for at least 15 days, achieving IFNα protection. In addition, pigs treated with IFNα-MPs exhibited overexpression of IFNα-stimulated genes 16 days after treatment. Instead, the expression levels of these genes decreased after day 4th in pigs treated with non-encapsulated IFNα. In vitro and in vivo experiments demonstrated that the formulation improved the prophylactic and therapeutic potential of IFNα, accomplishing molecule protection and long-term release for at least two weeks. The procedure used to obtain IFNα-MPs is reproducible, scalable, and suitable for encapsulating other drugs.

New strategy for the design, production and pre-purification of chimeric peptide with immunomodulatory activity in Salmosalar

The intensive salmon farming is associated with massive outbreaks of infections. The use of antibiotics for their prevention and control is related to damage to the environment and human health. Antimicrobial peptides (AMPs) have been proposed as an alternative to the use of antibiotics for their antimicrobial and immunomodulatory activities. However, one of the main challenges for its massive clinical application is the high production cost and the complexity of chemical synthesis. Thus, recombinant DNA technology offers a more sustainable, scalable, and profitable option. In the present study, using an AMPs function prediction methodology, we designed a chimeric peptide consisting of sequences derived from cathelicidin fused with the immunomodulatory peptide derived from flagellin. The designed peptide, CATH-FLA was produced by recombinant expression using an easy pre-purification system. The chimeric peptide was able to induce IL-1β and IL-8 expression in Salmo salar head kidney leukocytes, and prevented Piscirickettsia salmonis-induced cytotoxicity in SHK-1 cells. These results suggest that pre-purification of a recombinant AMP-based chimeric peptide designed in silico allow obtaining a peptide with immunomodulatory activity in vitro. This could solve the main obstacle of AMPs for massive clinical applications.

Salmonid MyD88 is a key adapter protein that activates innate effector mechanisms through the TLR5M/TLR5S signaling pathway and protects against Piscirickettsia salmonis infection

The membrane-anchored and soluble Toll-like Receptor 5 -TLR5M and TLR5S, respectively-from teleost recognize bacterial flagellin and induce the pro-inflammatory cytokines expression in a MyD88-dependent manner such as the TLR5 mammalian orthologous receptor. However, it has not been demonstrated whether the induced signaling pathway by these receptors activate innate effector mechanisms MyD88-dependent in salmonids. Therefore, in this work we study the MyD88 dependence on the induction of TLR5M/TLR5S signaling pathway mediated by flagellin as ligand on the activation of some innate effector mechanisms. The intracellular and extracellular Reactive Oxygen Species (ROS) production and conditioned supernatants production were evaluated in RTS11 cells, while the challenge with Piscirickettsia salmonis was evaluated in SHK-1 cells. Our results demonstrate that flagellin directly stimulates ROS production and indirectly stimulates it through the production of conditioned supernatants, both in a MyD88-dependent manner. Additionally, flagellin stimulation prevents the cytotoxicity induced by infection with P. salmonis in a MyD88-dependent manner. In conclusion we demonstrate that MyD88 is an essential adapter protein in the activation of the TLR5M/TLR5S signaling pathway mediated by flagellin in salmonids, which leads downstream to the induction of innate effector mechanisms, promoting immuno-protection against a bacterial challenge with P. salmonis.

The Hitchhiker's Guide to Human Therapeutic Nanoparticle Development

Nanomedicine plays an essential role in developing new therapies through novel drug delivery systems, diagnostic and imaging systems, vaccine development, antibacterial tools, and high-throughput screening. One of the most promising drug delivery systems are nanoparticles, which can be designed with various compositions, sizes, shapes, and surface modifications. These nanosystems have improved therapeutic profiles, increased bioavailability, and reduced the toxicity of the product they carry. However, the clinical translation of nanomedicines requires a thorough understanding of their properties to avoid problems with the most questioned aspect of nanosystems: safety. The particular physicochemical properties of nano-drugs lead to the need for additional safety, quality, and efficacy testing. Consequently, challenges arise during the physicochemical characterization, the production process, in vitro characterization, in vivo characterization, and the clinical stages of development of these biopharmaceuticals. The lack of a specific regulatory framework for nanoformulations has caused significant gaps in the requirements needed to be successful during their approval, especially with tests that demonstrate their safety and efficacy. Researchers face many difficulties in establishing evidence to extrapolate results from one level of development to another, for example, from an in vitro demonstration phase to an in vivo demonstration phase. Additional guidance is required to cover the particularities of this type of product, as some challenges in the regulatory framework do not allow for an accurate assessment of NPs with sufficient evidence of clinical success. This work aims to identify current regulatory issues during the implementation of nanoparticle assays and describe the major challenges that researchers have faced when exposing a new formulation. We further reflect on the current regulatory standards required for the approval of these biopharmaceuticals and the requirements demanded by the regulatory agencies. Our work will provide helpful information to improve the success of nanomedicines by compiling the challenges described in the literature that support the development of this novel encapsulation system. We propose a step-by-step approach through the different stages of the development of nanoformulations, from their design to the clinical stage, exemplifying the different challenges and the measures taken by the regulatory agencies to respond to these challenges.

The special case of the spectral emission of a Tb3+ mono metal complex

The fine structure in the spectral lines of the visible fluorescence of Tb 3+  complexes are replaced by a single peak in the case of a singular molecular complex Tb(H 3 PTC) 3  , where H 4 PTC represents perylene-3,4,9,10-tetracarboxylic acid, and its emission wavelength depends on the film thickness. This single peak challenges the old creed that the f-orbital electrons of Tb 3+  are always protected from the influence of the surrounding atoms. We perform density functional theory calculations to show that the wavefunction of the ground state is localized and in addition, spin-polarized, and this facilitates fluorescent transitions under UV to the first excited state instead of the fundamental state. We discuss the possibility of making a spintronic device with the molecule, Tb(H 3 PTC) 3  .

Raman spectroscopy and silver nanoparticles for efficient detection of membrane proteins in living cells

Molecular fingerprints revealed by Raman techniques show great potential for biomedical applications, like disease diagnostic through Raman detection of tumor markers and other molecules in the cell membrane. However, SERS substrates used in membrane molecule studies produce enhanced Raman spectra of high variability and challenging band assignments that limit their application. In this work, these drawbacks are addressed to detect membrane-associated hemoglobin (Hb_m) in human erythrocytes through Raman spectroscopy. These cells are incubated with silver nanoparticles (AgNPs) in PBS before Raman measurements. Our results showed that AgNPs form large aggregates in PBS that adhered to the erythrocyte membrane, which enhances Raman scattering by molecules around the membrane, like Hb_m. Also, deoxyHb markers may allow Hb_mdetection in Raman spectra of oxygenated erythrocytes (oxyRBCs). Raman spectra of oxyRBCs incubated with AgNPs showed enhanced deoxyHb signals with good spectral reproducibility, supporting the Hb_mdetection through deoxyHb markers. Instead, Raman spectra of oxyRBCs showed oxyHb bands associated with free cytoplasmic hemoglobin. Other factors influencing Raman detection of membrane proteins are discussed, like bothz-position and dimension of the sample volume. The results encourage membrane protein studies in living cells using Raman spectroscopy, leading to the characterization and diagnostic of different pathologies through a non-invasive technique.

A trivalent TNF-R2 as a new tumor necrosis factor alpha-blocking molecule

The neutralization of tumor necrosis factor alpha (TNFα) with biopharmaceuticals is a successful therapy for inflammatory diseases. Currently, one of the main TNFα-antagonists is Etanercept, a dimeric TNF-R2 ectodomain. Considering that TNFα and its receptors are homotrimers, we proposed that a trimeric TNF-R2 ectodomain could be an innovative TNFα-antagonist. Here, the 3cTNFR2 protein was designed by the fusion of the TNF-R2 ectodomain with the collagen XV trimerization domain. 3cTNFR2 was produced in HEK293 cells and purified by immobilized metal affinity chromatography. Monomers, dimers, and trimers of 3cTNFR2 were detected. The interaction 3cTNFR2-TNFα was assessed. By microscale thermophoresis, the K_D value for the interaction was 4.17 ± 0.88 nM, and complexes with different molecular weights were detected by size exclusion chromatography-high performance liquid chromatography. Moreover, 3cTNFR2 neutralized the TNFα-induced cytotoxicity totally in vitro. Although more studies are required to evaluate the anti-inflammatory effect, the results suggest that 3cTNFR2 could be a TNFα-antagonist agent.

Design and characterization of a novel dimeric blood-brain barrier penetrating TNFα inhibitor

Tumor necrosis factor-alpha (TNFα) inhibitors could prevent neurological disorders systemically, but their design generally relies on molecules unable to cross the blood-brain barrier (BBB). This research was aimed to design and characterize a novel TNFα inhibitor based on the angiopeptide-2 as a BBB shuttle molecule fused to the extracellular domain of human TNFα receptor 2 and a mutated vascular endothelial growth factor (VEGF) dimerization domain. This new chimeric protein (MTV) would be able to trigger receptor-mediated transcytosis across the BBB via low-density lipoprotein receptor-related protein-1 (LRP-1) and inhibit the cytotoxic effect of TNFα more efficiently because of its dimeric structure. Stably transformed CHO cells successfully expressed MTV, and its purification by Immobilized-Metal Affinity Chromatography (IMAC) rendered high purity degree. Mutated VEGF domain included in MTV did not show cell proliferation or angiogenic activities measured by scratch and aortic ring assays, which corroborate that the function of this domain is restricted to dimerization. The pairs MTV-TNFα (Kd 279 ± 40.9 nM) and MTV-LRP1 (Kd 399 ± 50.5 nM) showed high affinity by microscale thermophoresis, and a significant increase in cell survival was observed after blocking TNFα with MTV in a cell cytotoxicity assay. Also, the antibody staining in CHOK1 and bEnd3 cells demonstrated the adhesion of MTV to the LRP1 receptor located in the cell membrane. These results provide compelling evidence for the proper functioning of the three main domains of MTV individually, which encourage us to continue the research with this new molecule as a potential candidate for the systemic treatment of neurological disorders.

In vivo modification of the goat mammary gland glycosylation pathway

Complex recombinant glycoproteins produced as potential biopharmaceuticals in goat's milk have an aberrant pattern of N-glycosylation due to the lack of multi-antennary structures. Overexpression of glycosyltransferases may increase oligosaccharide branching of the desired glycoproteins. Here, human erythropoietin fused to human IgG Fc (EPO-Fc) was co-expressed with N-acetyl-glucosaminyltransferase-IVa (GnT-IVa) by adenoviral transduction in goat mammary gland to evaluate the in vivo modification of N-glycosylation pattern in this tissue. Adenoviral vectors, containing the EPO-Fc and GnT-IVa sequences were assembled for in vitro and in vivo expression in mammalian cell culture or in goat mammary gland. Protein detection was assessed by gel electrophoresis and western blot, and N-glycans were identified by HPLC and mass spectrometry. GnT-IVa overexpression and its colocalization with EPO-Fc in the Golgi apparatus of SiHa cells were demonstrated. N-glycan analysis of in vitro and in vivo expression of EPO-Fc modified by GnT-IVa (EPO-Fc/GnT-IVa) showed an increase in high molecular weight structures, which corresponded to tri- and tetra-antennary N-glycans in SiHa cells and mostly tri-antennary N-glycans in goat's milk from transformed mammary tissue. The results confirmed that successful modification of the goat mammary gland secretion pathway could be achieved by co-expressing glycoenzymes together with the glycoprotein of interest. This is the first report of modification of the N-glycosylation pattern in the goat mammary gland in vivo, and constitutes a step forward for improving the use of the mammary gland as a bioreactor for the production of complex recombinant proteins.

Maytenus disticha Extract and an Isolated β-Dihydroagarofuran Induce Mitochondrial Depolarization and Apoptosis in Human Cancer Cells by Increasing Mitochondrial Reactive Oxygen Species

Maytenus disticha (Hook F.), belonging to the Celastraceae family, is an evergreen shrub, native of the central southern mountains of Chile. Previous studies demonstrated that the total extract of M. disticha (MD) has an acetylcholinesterase inhibitory activity along with growth regulatory and insecticidal activities. β-Dihydroagarofurans sesquiterpenes are the most active components in the plant. However, its activity in cancer has not been analyzed yet. Here, we demonstrate that MD has a cytotoxic activity on breast (MCF-7), lung (PC9), and prostate (C4-2B) human cancer cells with an IC₅₀ (µg/mL) of 40, 4.7, and 5 µg/mL, respectively, an increasing Bax/Bcl2 ratio, and inducing a mitochondrial membrane depolarization. The β-dihydroagarofuran-type sesquiterpene (MD-6), dihydromyricetin (MD-9), and dihydromyricetin-3-O-β-glucoside (MD-10) were isolated as the major compounds from MD extracts. From these compounds, only MD-6 showed cytotoxic activity on MCF-7, PC9, and C4-2B with an IC₅₀ of 31.02, 17.58, and 42.19 µM, respectively. Furthermore, the MD-6 increases cell ROS generation, and MD and MD-6 induce a mitochondrial superoxide generation and apoptosis on MCF-7, PC9, and C4-2B, which suggests that the cytotoxic effect of MD is mediated in part by the β-dihydroagarofuran-type that induces apoptosis by a mitochondrial dysfunction.

In vitro immunomodulatory activities of peptides derived from Salmo salar NK-lysin and cathelicidin in fish cells

Antimicrobial peptides (AMPs) are amphipathic peptides, which play an important role in innate defence. These peptides are gene-encoded and either constitutively expressed and/or upregulated during an infection. NK-lysins are AMPs with a three-dimensional globular structure. They are larger molecules, which comprise 74-78 amino acid residues and six conserved cysteine residues forming three disulphide bonds. Cathelicidins are a family of antimicrobial peptides that act as important components of the innate immune system with a broad spectrum of antimicrobial activity and immunomodulatory properties. Although they are widely studied in mammals, little is known about their immunomodulatory function. In the present study, we identified and characterized for the first time four NK-lysin-like transcripts from Atlantic salmon (Salmo salar) based on EST reported sequences. In vitro, NK-lysin derived peptides were able to induce the expression of IL-1β and IL-8 in Salmo salar head kidney leukocytes. We also tested Salmo salar cathelicidin 1 derived peptide in a similar assay, showing its ability to induce the expression of IFN-γ. These results indicate that NK-lysin and cathelicidin 1 derived peptides are able to modulated immune response, suggesting their potential use to enhance immune response in fish.

Neuroprotective effects of EpoL against oxidative stress induced by soluble oligomers of Aβ peptide

Erythropoietin is a glycoproteic hormone that regulates hematopoiesis by acting on its specific receptor (EpoR). The expression of EpoR in the central nervous system (CNS) suggests a role for this hormone in the brain. Recently, we developed a new Epo variant without hematopoietic activity called EpoL, which showed marked neuroprotective effects against oxidative stress in brain ischemia related models. In this study, we have evaluated the neuroprotective effects of EpoL against oxidative stress induced by chronic treatment with Aβ. Our results show that EpoL was neuroprotective against Aβ-induced toxicity by a mechanism that implicates EpoR, reduction in reactive oxygen species, and reduction in astrogliosis. Furthermore, EpoL treatment improved calcium handling and SV2 levels. Interestingly, the neuroprotective effect of EpoL against oxidative stress induced by chronic Aβ treatment was achieved at a concentration 10 times lower than that of Epo. In conclusion, EpoL, a new variant of Epo without hematopoietic activity, is of potential interest for the treatment of diseases related to oxidative stress in the CNS such as Alzheimer disease.

FSH in bovine superovulation

Bovine follicle stimulating hormone (FSH) is the hormone mainly used for superovulation treatments. It is used so that several secondary follicles can reach a dominant state at the same time and thus, treated cows can release up to ten or more ovules in each zeal, decreasing the generational interval and increasing livestock production. The hormones available in the current market are obtained mostly from pituitary extracts of swine and sheep, and although they are widely used. Several negative aspects have been reported, implying high risks of contamination with pathogens, contamination with other hormones that interfere with assisted fertilization processes, significant variations between each production batch and the decreased half-life that exhibit FSH leading to excessive handling of donor cows. In this review, we detail some new approaches to overcome these problems, like slow-release FSH formulations that have been developed in order to increase the half-life of FSH and, finally the use of recombinant DNA technology to ensure a pure product.

Neuroprotective effect of a new variant of Epo nonhematopoietic against oxidative stress

Human erythropoietin is mainly recognized for its hematopoietic function; however, by binding to its receptor (EpoR), it can activate different signaling pathways as STAT, PI3K, MAPK and RAS to increase cellular differentiation or provide neuroprotective effects, among others. A recombinant human erythropoietin variant with low glycosylation and without hematopoietic effect (EpoL) was purified from skimmed goat milk. Recombinant human erythropoietin (Epo) was obtained from CHO cell line and used as control to compare EpoL effects. Neuroprotection studies were performed in PC12 cells and rat hippocampal slices. Cells were pretreated during 1h with EpoL or Epo and exposed to oxidative agents (H2O2 or FCCP); cell viability was assayed at the end of the experiment by the MTT method. Hippocampal slices were exposed to 15min of oxygen and glucose deprivation (OGD) and the neuroprotective drugs EpoL or Epo were incubated for 2h post-OGD in re-oxygenated medium. Cell cultures stressed with oxidative agents, and pretreated with EpoL, showed neuroprotective effects of 30% at a concentration 10 times lower than that of Epo. Moreover, similar differences were observed in OGD ex vivo assays. Neuroprotection elicited by EpoL was lost when an antibody against EpoR was present, indicating that its effect is EpoR-dependent. In conclusion, our results suggest that EpoL has a more potent neuroprotective profile than Epo against oxidative stress, mediated by activation of EpoR, thus EpoL represents an important target to develop a potential biopharmaceutical to treat different central nervous system pathologies related to oxidative stress such as stroke or neurodegenerative diseases.

LOX-1 activation by oxLDL triggers an epithelial mesenchymal transition and promotes tumorigenic potential in prostate cancer cells

Obesity is related to an increased risk of developing prostate cancer with high malignancy stages or metastasis. Recent results demonstrated that LOX-1, a receptor associated with obesity and atherosclerosis, is overexpressed in advanced and metastatic prostate cancer. Furthermore, high levels of oxLDL, the main ligand for LOX-1, have been found in patients with advanced prostate cancer. However, the role of LOX-1 in prostate cancer has not been unraveled completely yet. Here, we show that LOX-1 is overexpressed in prostate cancer cells and its activation by oxLDL promotes an epithelial to mesenchymal transition, through of lowered expression of epithelial markers (E-cadherin and plakoglobin) and an increased expression of mesenchymal markers (vimentin, N-cadherin, snail, slug, MMP-2 and MMP-9). Consequently, LOX-1 activation by oxLDL promotes actin cytoskeleton restructuration and MMP-2 and MMP-9 activity inducing prostate cancer cell invasion and migration. Additionally, LOX-1 increased the tumorigenic potential of prostate cancer cells and its expression was necessary for tumor growth in nude mice. In conclusion, our results suggest that oxLDL/LOX-1 could be ones of mechanisms that explain why obese patients with prostate cancer have an accelerated tumor progression and a greater probability of developing metastasis.

Bone stroma-derived cells change coregulators recruitment to androgen receptor and decrease cell proliferation in androgen-sensitive and castration-resistant prostate cancer cells

Prostate cancer (CaP) bone metastasis is an early event that remains inactive until later-stage progression. Reduced levels of circulating androgens, due to andropause or androgen deprivation therapies, alter androgen receptor (AR) coactivator expression. Coactivators shift the balance towards enhanced AR-mediated gene transcription that promotes progression to androgen-resistance. Disruptions in coregulators may represent a molecular switch that reactivates latent bone metastasis. Changes in AR-mediated transcription in androgen-sensitive LNCaP and androgen-resistant C4-2 cells were analyzed for AR coregulator recruitment in co-culture with Saos-2 and THP-1. The Saos-2 cell line derived from human osteosarcoma and THP-1 cell line representing human monocytes were used to display osteoblast and osteoclast activity. Increased AR activity in androgen-resistant C4-2 was due to increased AR expression and SRC1/TIF2 recruitment and decreased SMRT/NCoR expression. AR activity in both cell types was decreased over 90% when co-cultured with Saos-2 or THP-1 due to dissociation of AR from the SRC1/TIF2 and SMRT/NCoR coregulators complex, in a ligand-dependent and cell-type specific manner. In the absence of androgens, Saos-2 decreased while THP-1 increased proliferation of LNCaP cells. In contrast, both Saos-2 and THP-1 decreased proliferation of C4-2 in absence and presence of androgens. Global changes in gene expression from both CaP cell lines identified potential cell cycle and androgen regulated genes as mechanisms for changes in cell proliferation and AR-mediated transactivation in the context of bone marrow stroma cells.

Expression and purification of the surface proteins from Andes virus

Andes virus is the main causative agent of Hantavirus cardiopulmonary syndrome in South America. There are currently no vaccines or treatments against Andes virus. However, there are several evidences suggesting that antibodies against Andes virus envelope glycoproteins may be enough to confer full protection against Hantavirus cardiopulmonary syndrome. The goal of the present work was to express, purify and characterize the extracellular domains of Andes virus glycoproteins Gn and Gc. We generated two adenoviral vectors encoding the extracellular domains of Andes virus glycoproteins Gn and Gc. Both molecules were expressed by adenoviral transduction in SiHa cells. We found that sGc ectodomain was mainly secreted into the culture medium, whereas sGn was predominantly retained inside the cells. Both molecules were expressed at very low concentrations (below 1 μg/mL). Treatment with the proteasome inhibitor ALLN raised sGc concentration in the cell culture medium, but did not affect expression levels of sGn. Both ectodomains were purified by immobilized metal ion affinity chromatography, and were recognized by sera from persons previously exposed to Andes virus. To our knowledge, this is the first work that addresses the expression and purification of Andes virus glycoproteins Gn and Gc. Our results demonstrate that sGn and sGc maintain epitopes that are exposed on the surface of the viral envelope. However, our work also highlights the need to explore new strategies to achieve high-level expression of these proteins for development of a vaccine candidate against Andes virus.

Cis-regulatory elements involved in species-specific transcriptional regulation of the SVCT1 gene in rat and human hepatoma cells

Ascorbic acid is transported into cells by the sodium-coupled vitamin C transporters (SVCTs). Recently, we obtained evidence of differential regulation of SVCT expression in response to acute oxidative stress in cells from species that differ in their capacity to synthesize vitamin C, with a marked decrease in SVCT1 mRNA and protein levels in rat hepatoma cells that was not observed in human hepatoma cells. To better understand the regulatory aspects involved, we performed a structural and functional analysis of the proximal promoter of the SVCT1 rat gene. We cloned a 1476-bp segment containing the proximal promoter of the rat SVCT1 gene and generated deletion-derived truncated promoters of decreasing sizes and mutant promoters by modification of consensus binding sites for transcription factors by site-directed mutagenesis. We next analyzed their capacity to direct the transcription of a reporter gene after transfection into rat H4IIE and human HepG2 hepatoma cells, in experiments involving the coexpression of transcription factors whose consensus binding sequences are present in the SVCT1 promoter. This analysis revealed the presence of two critical cis-regulatory elements of the transcriptional activity of the rat SVCT1 gene promoter, sites containing consensus sequences for the binding of the transcription factors Bach1 and HNF4 that are not present in equivalent locations in the human SVCT1 gene promoter. Moreover, a consensus site for HNF1 that is crucial for the regulation of the human SVCT1 promoter is present in the SVCT1 rat promoter but has no effect on its transcriptional activity. These findings imply that regulation of vitamin C metabolism in the rat, a species with the capacity to synthesize large amounts of ascorbic acid, may differ from that of humans, a species that must obtain ascorbic acid from the diet through a transport mechanism that depends on proper SVCT1 expression.

Post-translational modification of a chimeric EPO-Fc hormone is more important than its molecular size in defining its in vivo hematopoietic activity

BACKGROUND

Recombinant erythropoietin (EPO) has been marketed as biopharmaceutical for anemia and chronic renal failure. Long-acting EPO variants that aimed at achieving less frequent dosing have been generated, either by the addition of glycosylation sites or increasing its molecular weight.

METHODS

The hEPO cDNA linked to the human IgG Fc fragment was cloned as a single codifying gene on the pAdtrack-CMV vector, yielding the recombinant adenoviral genome. For in vitro and in vivo expression assays cervical cancer cell line (SiHa) and nulliparous goats were used, respectively. The hematopoietic activity of EPO-Fc, expressed as the differential increment of hematocrit was evaluated in B6D2F1 mice. NP-HPLC of the 2AB-labeled N-glycan was carried out to profile analysis.

RESULTS

The direct transduction of mammary secretory cells with adenoviral vector is a robust methodology to obtain high levels of EPO of up to 3.5mg/mL in goat's milk. SiHa-derived EPO-Fc showed significant improvement in hematopoietic activity compared to the commercial hEPO counterpart or with the homologous milk-derived EPO-Fc. The role of the molecular weight seemed to be important in enhancing the hematopoietic activity of SiHa-derived EPO-Fc. However, the lack of sialylated multi-antennary glycosylation profile in milk-derived EPO-Fc resulted in lower biological activity.

CONCLUSIONS

The low content of tri- or tetra-antennary sialylated N-glycans linked to the chimeric EPO-Fc hormone, expressed in the goat mammary gland epithelial cells, defined its in vivo hematopoietic activity.

GENERAL SIGNIFICANCE

The sialylated N-glycan content plays a more significant role in the in vivo biological activity of hEPO than its increased molecular weight.

Lectin-like oxidized LDL receptor-1 is an enhancer of tumor angiogenesis in human prostate cancer cells

Altered expression and function of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) has been associated with several diseases such as endothelial dysfunction, atherosclerosis and obesity. In these pathologies, oxLDL/LOX-1 activates signaling pathways that promote cell proliferation, cell motility and angiogenesis. Recent studies have indicated that olr1 mRNA is over-expressed in stage III and IV of human prostatic adenocarcinomas. However, the function of LOX-1 in prostate cancer angiogenesis remains to be determined. Our aim was to analyze the contribution of oxLDL and LOX-1 to tumor angiogenesis using C4-2 prostate cancer cells. We analyzed the expression of pro-angiogenic molecules and angiogenesis on prostate cancer tumor xenografts, using prostate cancer cell models with overexpression or knockdown of LOX-1 receptor. Our results demonstrate that the activation of LOX-1 using oxLDL increases cell proliferation, and the expression of the pro-angiogenic molecules VEGF, MMP-2, and MMP-9 in a dose-dependent manner. Noticeably, these effects were prevented in the C4-2 prostate cancer model when LOX-1 expression was knocked down. The angiogenic effect of LOX-1 activated with oxLDL was further demonstrated using the aortic ring assay and the xenograft model of tumor growth on chorioallantoic membrane of chicken embryos. Consequently, we propose that LOX-1 activation by oxLDL is an important event that enhances tumor angiogenesis in human prostate cancer cells.

Human αIFN co-formulated with milk derived E2-CSFV protein induce early full protection in vaccinated pigs

Subunit vaccines are a suitable alternative for the control of classical swine fever. However, such vaccines have as the main drawback the relatively long period of time required to induce a protective response, which hampers their use under outbreak conditions. In this work, type I interferon is used as an immunostimulating molecule in order to increase the immunogenicity of a vaccine candidate based on the E2-CSFV antigen produced in goat milk. Pigs vaccinated with E2-CSFV antigen co-formulated with recombinant human alpha interferon were protected against clinical signs and viremia as early as 7 days post-vaccination. It was also demonstrated that interferon stimulates a response of specific anti-CSFV neutralizing antibodies. The present work constitutes the first report of a subunit vaccine able to confer complete protection by the end of the first week after vaccination. These results suggest that the E2-CSFV antigen combined with type I interferons could be potentially used under outbreak conditions to stop CSFV spread and for eradication programs in CSF enzootic areas.

N-glycosylation pattern of E2 glycoprotein from classical swine fever virus

The extracellular domain of E2 glycoprotein outer surface of the classical swine fever virus was expressed in epithelial kidney pig cells. The N-glycosylation determined by combination of Normal Phase-HPLC, Weak Anion Exchange-HPLC, exoglycosidase digestions and Mass Spectrometry revealed a complex mixture of neutral and monosialylated multiantennary N-glycans with variable number of alpha1-3-Gal-Gal antennae terminals. The most abundant neutral N-glycan has a composition of Hex(7)HexNAc(4)dHex(1), Negative ion ESI-MS/MS confirmed the presence of the alpha1-3-Gal-Gal motif on each arm of the fucosylated biantennary N-glycan. The most abundant monosialylated glycan was Hex(6)HexNAc(4)dHex(1)Neu(5)Ac(1), with the sialic acid linked to the terminal beta1-4-Gal-GlcNAc. Sialic acid on the antenna capping position was predominantly of the N-acetyl form.

Classical swine fever virus E2 glycoprotein antigen produced in adenovirally transduced PK-15 cells confers complete protection in pigs upon viral challenge

E2 is the major envelope glycoprotein present on the outer surface of the classical swine fever virus (CSFV). It is exposed as a homodimer originated by disulfide linkage and represents an important target for the induction of neutralizing immune responses against the viral infection. The E2his glycoprotein nucleotide sequence used in this work contains the CSFV E2 extracellular domain preceded by the tissue plasminogen signal peptide and a hexa-histidine tag in the 3' terminus. The recombinant antigen was produced at a range of 120-150 microg/mL in the culture media of epithelial kidney pig cells, transduced with a replication defective adenoviral vector (Ad-E2his) generated by means of cloning the E2his sequence in the vector genome. The glycoprotein was obtained from clarified culture media as a homodimer of 110 kDa with purity over 95% after a single affinity chromatography step in Ni-NTA Agarose column. The E2his characterization by lectin-specific binding assay showed the presence of N-linked oligosaccharides of both hybrid and complex types. The protective capacity of E2his was demonstrated in two immunization and challenge experiments in pigs using doses of 15 or 30 microg of the glycoprotein, emulsified in Freund's adjuvant. The intramuscular immunization followed by a unique boost three weeks later, elicited high titers of neutralizing antibodies between the second and the fourth week after the primary vaccination. The immunized animals were fully protected from the viral infection after challenge with 10(5) PLD(50) of homologous CSFV "Margarita" strain administered by intramuscular injection. Consequently, no clinical signs of the disease or viral isolation from lymphocytes were detected in the vaccinated pigs. These results suggest that the E2his antigen produced in mammalian cells may be a feasible vaccine candidate for CSF prevention.

The goat mammary glandular epithelial (GMGE) cell line promotes polyfucosylation and N,N′-diacetyllactosediaminylation of N-glycans linked to recombinant human erythropoietin

We have established a continuous, non-transformed cell line from primary cultures from Capra hircus mammary gland. Low-density cultures showed a homogeneous epithelial morphology without detectable fibroblastic or myoepithelial cells. The culture was responsive to contact inhibition of proliferation and its doubling time was dependent on the presence of insulin and epidermal growth factor (EGF). GMGE cells secrete caseins regardless of the presence or absence of lactogenic hormones in the culture media. Investigation of the total N-glycan pool of human erythropoietin (rhEPO) expressed in GMGE cells by monosaccharide analysis, HPLC profiling, and mass spectrometry, indicated significant differences with respect to the same protein expressed in Chinese hamster ovary (CHO) cells. N-Glycans of rhEPO-GMGE are core-fucosylated, but fucosylation of outer arms was also found. Our results also revealed the presence of low levels of sialylation (>95% Neu5Ac), N,N'-diacetyllactosediamine units, and possibly Gal-Gal non-reducing terminal elements.

Molecular and antigenic characterization of rabbit hemorrhagic disease virus isolated in Cuba indicates a distinct antigenic subtype

Phylogenetic analyses conducted on isolates of rabbit hemorrhagic disease virus (RHDV) from throughout the world have shown well-defined genogroups comprising representative strains of the virus and antigenic variants. In this work, we have isolated and characterized RHDV from the major epizootic that occurred in Cuba in 2004-2005. Sequence analysis of the capsid protein gene and antigenic characterization of this strain has allowed its inclusion as a member of the distinct RHDVa subtype. We also found that specific antibodies directed against RHDV reference strains bound to the Cuban isolate in a competition ELISA and inhibited virus hemagglutination in vitro. This is the second report on the molecular characterization of RHDVa circulating in the American region.

High expression level of recombinant human erythropoietin in the milk of non-transgenic goats

The high degree of structural conservation of erythropoietin between species, make it, especially, difficult to produce this protein growth factor in the milk of transgenic animals. Here, we show that through the direct transduction of the mammary epithelium, it is possible to produce high levels of recombinant human erythropoietin in the milk of non-transgenic goats without causing harm to the animals. The efficiency of viral transduction was improved through a temporal disruption of tight-junctions with EGTA allowing for the expression of human erythropoietin at levels of up to 2g/L in milk. The human erythropoietin was purified from the milk using a multi-step protocol involving milk clarification, two precipitation steps and two affinity chromatographies, with a yield of about 70% and purity over 98%. However, the human erythropoietin expressed in milk was underglycosylated, which seems to be the main cause for its low in vivo hematopoietic activity. Nonetheless, these results demonstrate that through the direct transduction of the mammary epithelium it is possible to produce potentially toxic proteins in milk, at levels high enough for their purification and biological characterization.

Differential in vitro and in vivo glycosylation of human erythropoietin expressed in adenovirally transduced mouse mammary epithelial cells

The expression of human erythropoietin in the mammary gland is an attractive approach to diminish its current production cost. Previous attempts to produce erythropoietin in the milk of transgenic animals resulted in very low expression levels and in a detrimental effect in the health of the founder animals. Here, we show that the direct transduction of the mouse mammary gland with an adenoviral vector carrying the cDNA of erythropoietin promotes its expression in milk at a level as high as 3.5 mg/ml. The recombinant erythropoietin derived from mouse milk showed a different migration and distribution after SDS-PAGE electrophoresis as well as a low in vivo hematopoietic activity. Enzymatic deglycosylation showed that these molecular weight disparities are in part due to differential glycosylation compared to with its counterpart produced in CHO and HC11 cell lines. The difference between in vivo and in vitro glycosylation of human erythropoietin expressed in adenovirally transduced mammary epithelial cells suggests that key enzymes in the glycosylation pathway may be insufficient during lactation. Thus, the direct transduction of the mammary epithelium seems to be a powerful tool to express toxic proteins in milk at levels high enough for their physical, chemical and biological characterization before undertaking the generation of a transgenic mammal.

Adenoviral vector mediates high expression levels of human growth hormone in the milk of mice and goats

The production of large quantities of complex proteins with biopharmaceutical purposes is the main drawback for their more extensive use. Here we demonstrated that a direct instillation of a recombinant adenoviral vector containing an expression cassette for the human growth hormone gene into the mammary gland of mice and goats allowed for the efficient secretion of human growth hormone in the milk. Through this approach we were able to express human growth hormone at maximal levels of 2.8 mg/ml in the milk of mice and up to 0.3 mg/ml in goat milk. We found that the expression levels were closely dependent on both the degree of differentiation of the secretory epithelium and on the adenoviral dose used. Here we demonstrated that the direct transduction of mammary epithelial cells by means of a recombinant adenovirus could be a suitable alternative to transgenic technology for the production of recombinant proteins of biopharmaceutical interest.

Computed tomographic study of cervical carotid calcification

Contrast-enhanced computed tomography of the neck permits low-risk evaluation of morphologic complications of carotid plaque, including (and foremost) calcification. To investigate the patterns and clinical significance of calcified deposits in the cervical carotid arteries using computed tomography we studied 40 patients with unilateral symptoms of hemispheric ischemia. Calcium deposits observed in the external, internal, and common carotid arteries were oriented in space and individually scored. We found calcified deposits in 39 patients. Stepwise multiple regression of the data provided evidence strongly suggesting a correlation between advancing age and calcium scores. Calcium was more heavily concentrated in the posterior half of arteries (p less than 0.01), in particular of the internal and common carotid arteries, and always in relation to an atheromatous plaque, suggesting a causative link to hemodynamic forces within the arteries. There was no difference in calcification scores between symptomatic and asymptomatic sides, indicating that calcium deposits do not contribute to the development of symptoms.

Endorphins and placebo fear reduction

This study examined whether endorphins play a role in placebo fear reduction in addition to their apparent mediation of placebo analgesia. 27 female undergraduate students were intravenously administered either saline or the endorphin antagonist, naloxone, under double-blind conditions prior to exposure to a nonspecific analogue treatment for snake fear. Analysis indicated that the two groups of subjects performed comparably and significantly better than no-treatment controls on posttest measures of self-efficacy, self-rated fear, and approach toward a live, harmless snake. These preliminary findings suggest that a mechanism other than endorphin release underlies fear reduction in psychological placebo treatments.