Genetic determinants of 5-lipoxygenase pathway in a Spanish population and their relationship with cardiovascular risk

OBJECTIVE

Leukotrienes (LT) play a role in inflammation, cardiovascular diseases, and cancer. Although some studies suggest that there are genes that determine variability of some LT-related phenotypes, the genetic influence on these phenotypes has not been evaluated.

METHODS

The relative contributions of genetic and environmental influences to the 5-lipoxygenase pathway-related phenotypes (5-Lipoxygenase, five lipoxygenase activating protein (FLAP), LTA(4)-hydrolase and LTC(4)-synthase expression, and LTB(4)-plasma concentration and LTB(4) production by stimulated whole blood) were assessed in a sample of 934 individuals in 35 extended families. Our design is based on extended families recruited through a probands with idiopathic thrombophilia. This strategy allows us the analysis of the effects of measured covariates (such as sex, age and smoking), genes, and environmental variables shared by members of a household.

RESULTS

All of these phenotypes showed significant genetic contributions, with heritabilities ranging from 0.33 to 0.51 for enzyme expression and from 0.25 to 0.50 for LTB(4) production of the residual phenotypic variance. Significant phenotypic and genetic correlation among the LT-related traits was found. More importantly, FLAP and LTA(4)-hydrolase expression exhibit significant genetic correlations with arterial thrombosis, indicating that some of the genes that influence quantitative variation in these phenotypes also influence the risk of thrombosis.

CONCLUSION

This is the first study that quantifies the genetic component of 5-Lipoxygenase pathway phenotypes. The high heritability of these traits and the significant genetic correlations between arterial thrombosis and some of these phenotypes suggest that the exploitation of correlated quantitative phenotypes will aid the search for susceptibility genes.

Imidazolineoxyl N-oxide induces COX-2 in endothelial cells: role of free radicals

cPTIO (2-[4-carboxyphenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) exerts beneficial actions on systemic inflammatory response. Besides its nitric oxide (NO) scavenging properties cPTIO could exert beneficial effects through modulation of arachidonic acid metabolism. We studied the effect of cPTIO on the biosynthesis of vasoactive prostaglandins (PG) by endothelial cells. Human cord umbilical vein endothelial cells (HUVEC) were treated with cPTIO, and expression of cycloxygenase (COX) isoenzymes in terms of mRNA and protein was determined by real-time-PCR and immunoblotting. Release of PGE2 (as index of untransformed PGH2 release) and 6-oxo-PGF1alpha (PGI2 stable metabolite) was determined by enzyme-immunoassay. cPTIO significantly increases the release of untransformed PGH2 associated to the induction of COX-2 expression. Experiments with NO-synthase inhibitors and radical scavengers showed that induction of COX-2 by cPTIO was mediated by free radical species, likely caused by the mobilization of NO from cellular stores. Finally, using specific signal-transduction inhibitors we show the involvement of Src/PI3-K/PKC pathway. Additional effects other than a direct NO scavenging activity may confer therapeutic advantages to cPTIO as compared with NO-synthase inhibitors for the treatment of systemic inflammation-associated vascular hyporeactivity.

Gene expression as a predictor of radiotherapy or chemoradiotherapy response in head and neck squamous cell carcinoma patients: A molecular approach

5590

Background: There are not validated markers of radioresistance in patients with a head and neck squamous cell carcinoma (HNSCC). The objective of our study was to explore the relationship between response to radiotherapy and the expression at transcriptional level of a panel of genes related with the HNSCC carcinogenic process. Methods: The study group was 76 consecutive HNSCC patients treated with radiotherapy (n=51) or chemoradiotherapy (n=25) with curative intention, and a minimum follow-up of three years. Thirty-seven patients were T1-T2 tumors and 16 had an advanced tumor (T3-T4). Biopsy specimens were performed from the primary tumor before treatment and conveniently stored until processing. Expression of genes related with cell cycle (cyclin D1), apoptosis (Bcl-XL), angiogenesis (VEGF), inflammation (IL-8), and tissue invasiveness (MMP-2 and MMP-9) were examined using a RT-PCR method. The continuous value of the mRNA expression level was evaluated with a classification and regression tree (CRT) method, considering the local control of the disease achieved with radiotherapy as the dependent variable. Results: During the follow-up 26 patients (33.8%) had a local failure. The CRT method found a significant relationship between VEGF and MMP-9 expression and local control of the disease. According the expression level of VEGF and MMP-9 the patients were classified in three groups: the A group (n=19) defined by a low expression of VEGF, the B group (n=19) defined by a high expression of VEGF and a low expression of MMP-9 and the C group (n=38) defined by a high expression of both VEGF and MMP-9. The 5-year local recurrence free survival was: A group 94.7% (CI 95%: 84.7-100%), B group 83.3% (CI 95%: 66.1-100%), and C group 37.6% (CI 95%: 21.0-54.2%). There were significant differences in the local control of the disease according to the VEGF and MMP-9 expression values (test log rank, P<0.0001). Conclusions: Expression of VEGF and MMP-9 genes may be a radiosensitivity marker for patients with HNSCC treated with radical intention. We didn’t find prognostic significance for other genes explored.

First Report of Fruit Rot on Plum Caused by Monilinia fructicola at Alcalá del Río (Seville), Southwestern Spain

Monilinia fructicola, causal agent of brown rot, is one of the most important fungal pathogens of stone fruit. In the summer of 2011, Japanese plum fruit of 'Larry Ann' (Prunus salicina Lindl) showing symptoms of fruit rot disease were detected and collected from trees in an experimental field at Alcalá del Río (Seville), southwestern Spain. Fruit rot lesions were brown, sunken, and covered with grayish brown tufts or pustules. The majority of infected fruit became dry and mummified on the trees after 30 days. Symptoms were similar to those caused by three Monilinia species, M. laxa, M. fructigena, and M. fructicola (2). Pieces of infected tissue, previously disinfested in 0.6% NaOCl, were placed on potato dextrose agar (PDA) amended with 50 μg of streptomycin per liter and incubated at 22°C with a 12-h photoperiod for 15 days. The isolates produced abundant, grayish white mycelium, which after sporulation became hazel in color, and colonies displayed concentric rings. Colonies produced scarce conidia, which were arranged in branched, monilioid chains. Conidia were one celled, hyaline, ellipsoid to lemon shaped, and measured 15.42 ± 1.91 × 8.02 ± 0.9 μm. The morphological data and growth rates match the description of M. fructicola (Winter) Honey (2-4). Fungal identification was confirmed by PCR using genomic DNA extracted from the mycelia of pure cultures. The DNA was amplified with a common reverse primer and three specific forward primers obtained from a sequence-characterized, amplified region that distinguishes between M. fructicola, M. fructigena, and M. laxa. The size of the amplified fragment (a product of 535 bp) fit with the one described for M. fructicola (2). To confirm the pathogenicity of the isolate, mature 'Larry Ann' and 'Sungold' plum fruits (six fruits per cultivar) were inoculated by placing an agar plug from the edge of an actively growing colony on PDA directly on the fruit surface. After 5 days of incubation, typical brown rot symptoms developed on inoculated fruit and the fungus was successfully reisolated, thus fulfilling Koch's postulates. No symptoms appeared on control fruit. To our knowledge, this is the first report of M. fructicola on plums in southwestern Spain. M. fructicola is a quarantined pathogen in Europe and has been reported on imported apricot and nectarine (1) and peach in several European countries (3,4). References: (1) E. Bosshard et al. Plant Dis. 90:1554, 2006. (2) M. J. Côté. Plant Dis. 88:1219, 2004. (3) A. De Cal and I. Gell. Plant Dis. 93:763, 2009. (4). C. Pellegrino et al. Plant Dis. 93:668, 2009.

Overexpression of the nuclear factor-kappa B (p65) in association with local failure in patients with head and neck carcinoma undergong radiotherapy or chemoradiotherapy

BACKGROUND

The aim of this study was to evaluate nuclear factor-kappa B (NF-κB) expression as a biologic marker to predict local control in patients with head and neck squamous cell carcinoma (HNSCC) treated with radiotherapy or chemoradiotherapy.

METHODS

The mRNA expression levels of the NF-κB family genes were determined with real-time-polymerase chain reaction in 77 patients with HNSCC treated with radiotherapy or chemoradiotherapy.

RESULTS

The mRNA NF-κB (p65) expression in pretreatment tumors was significantly related to local control (p = .03). The 5-year local recurrence-free survival rate in patients with low-level NF-κB (p65) expression (n = 42) was 79.9%, and in patients with a high level of expression it was 42.1% (p = .001). In a multivariate analysis, the mRNA NF-κB (p65) expression level was the only variable related to local control of the tumor.

CONCLUSION

Expression of the NF-κB (p65) gene may be a radiosensitivity marker for patients with a HNSCC.

Interaction between head and neck squamous cell carcinoma cells and fibroblasts in the biosynthesis of PGE2

Prostaglandin (PG)E(2) is relevant in tumor biology, and interactions between tumor and stroma cells dramatically influence tumor progression. We tested the hypothesis that cross-talk between head and neck squamous cell carcinoma (HNSCC) cells and fibroblasts could substantially enhance PGE(2) biosynthesis. We observed an enhanced production of PGE(2) in cocultures of HNSCC cell lines and fibroblasts, which was consistent with an upregulation of COX-2 and microsomal PGE-synthase-1 (mPGES-1) in fibroblasts. In cultured endothelial cells, medium from fibroblasts treated with tumor cell-conditioned medium induced in vitro angiogenesis, and in tumor cell induced migration and proliferation, these effects were sensitive to PGs inhibition. Proteomic analysis shows that tumor cells released IL-1, and tumor cell-induced COX-2 and mPGES-1 were suppressed by the IL-1-receptor antagonist. IL-1α levels were higher than those of IL-1β in the tumor cell-conditioning medium and in the secretion from samples obtained from 20 patients with HNSCC. Fractionation of tumor cell-conditioning media indicated that tumor cells secreted mature and unprocessed forms of IL-1. Our results support the concept that tumor-associated fibroblasts are a relevant source of PGE(2) in the tumor mass. Because mPGES-1 seems to be essential for a substantial biosynthesis of PGE(2), these findings also strengthen the concept that mPGES-1 may be \a target for therapeutic intervention in patients with HNSCC.

Salt gland adenitis as only cause of stranding of loggerhead sea turtles Caretta caretta

The present study describes pathological and microbiological findings in 9 stranded loggerhead sea turtles Caretta caretta, whose only observed lesion was bilateral purulent salt gland adenitis. Histological lesions ranged from the presence of abundant eosinophilic material associated with bacterial colonies in the lumen of the central ducts of the glandular lobules to the destruction of the glandular tissue and presence of abundant eosinophilic material composed of heterophils and cell debris, lined by multinucleated giant cells. Aeromonas hydrophila, Staphylococcus sp., and Vibrio alginolyticus were the bacteria most frequently isolated. Plasma concentrations of sodium and chloride and plasma osmolality from 2 turtles suffering from salt gland adenitis were, respectively 45.7, 69.2, and 45.7% higher than the mean value for healthy turtles. These cases suggest that failure to maintain homeostasis due to severe lesions in the salt glands can cause stranding and/or death of loggerhead sea turtles.

Hypoxia upregulates PGI-synthase and increases PGI₂ release in human vascular cells exposed to inflammatory stimuli

Hypoxia affects vascular function and cell metabolism, survival, growth, and motility; these processes are partially regulated by prostanoids. We analyzed the effect of hypoxia and inflammation on key enzymes involved in prostanoid biosynthesis in human vascular cells. In human vascular smooth muscle cells (VSMC), hypoxia and interleukin (IL)-1β synergistically increased prostaglandin (PG)I₂ but not PGE₂ release, thereby increasing the PGI₂/PGE₂ ratio. Concomitantly, these stimuli upregulated cyclooxygenase-2 (COX-2) expression (mRNA and protein) and COX activity. Interestingly, hypoxia enhanced PGI-synthase (PGIS) expression and activity in VSMC and human endothelial cells. Hypoxia did not significantly modify the inducible microsomal-PGE-synthase (mPGES)-1. Hypoxia-inducible factor (HIF)-1α-silencing abrogated hypoxia-induced PGIS upregulation. PGIS transcriptional activity was enhanced by hypoxia; however, the minimal PGIS promoter responsive to hypoxia (-131 bp) did not contain any putative hypoxia response element (HRE), suggesting that HIF-1 does not directly drive PGIS transcription. Serial deletion and site-directed mutagenesis studies suggested several transcription factors participate cooperatively. Plasma levels of the stable metabolite of PGI₂ and PGIS expression in several tissues were also upregulated in mice exposed to hypoxia. These data suggest that PGIS upregulation is part of the adaptive response of vascular cells to hypoxic stress and could play a role in counteracting the deleterious effect of inflammatory stimuli.

Tumor cells induce COX-2 and mPGES-1 expression in microvascular endothelial cells mainly by means of IL-1 receptor activation

Prostaglandin (PG) E(2) plays a key role in immune response, tumor progression and metastasis. We previously showed that macrovessel-derived endothelial cells do not produce PGE(2) enzymatically because they do not express the inducible microsomal PGE-synthase-1 (mPGES-1). Nevertheless, differences between macro- and micro-vessel-derived endothelial cells regarding arachidonic acid (AAc) metabolism profile have been reported. The present work was conducted to evaluate the expression of PGE(2)-pathway-related enzymes in human microvascular endothelial cells (HMVEC) in culture and to test the hypothesis that the tumor cell-HMVEC cross talk could increase mPGES-1 expression in HMVEC. We treated HMVEC in culture with human recombinant IL-1β. IL-1β induced PGE(2) release and COX-2 and mPGES-1 expression in terms of mRNA and protein, determined by real-time PCR and immunoblotting, respectively. HMVEC constitutively expressed mPGES-2 and cytosolic PGES (cPGES) and the IL-1β treatment did not modify their expression. PGE(2) synthesized by HMVEC from exogenous AAc was linked to mPGES-1 expression. Immunohistochemistry analysis confirmed mPGES-1 expression in microvessels in vivo. COX-2 and mPGES-1 were also induced in HMVEC by the conditioned medium from two squamous head and neck carcinoma cell lines. Conditioned medium from tumor cell cultures contained several cytokines including the IL-1β and IL-1α. Tumor cell-induced COX-2 and mPGES-1 in HMVEC was strongly inhibited by the IL-1-receptor antagonist, indicating the important implication of IL-1 in this effect. HMVEC could therefore contribute directly to PGE(2) formed in the tumor. Our findings support the concept that mPGES-1 could be a target for therapeutic intervention in patients with cancer.

[Staphylococcus aureus: new and old antimicrobial agents]

The objective of the study was to evaluate the susceptibility to old and new antimicrobial agents against hospital-acquired oxacillin-resistant Staphylococcus aureus (HA-ORSA), community-acquired oxacillin-resistant S. aureus (CA-ORSA), and oxacillin-susceptible S. aureus(OSSA). The minimum inhibitory concentration of different antimicrobial agents against 118 S. aureus consecutive and prospective isolates was studied by the CLSI agar dilution method. In ORSA isolates without accompanying resistance, the mecA gene, the Panton-Valentine leukocidin gene (PVL), and the gamma-hemolysin gene were determined by PCR, and the SCC cassette mec gene by multiplex PCR. Out of the 118 isolates, 44 were HA-ORSA, 16 were CA-ORSA, and 58 corresponded to OSSA. The HA-ORSA isolates presented simultaneous resistance to erythromycin, clindamycin, gentamicin, ciprofloxacin, levofloxacin, and moxifloxacin whereas all of them were susceptible to tigecycline (TIG), vancomycin, teicoplanin and linezolid (LZD). The CA-ORSA isolates were only resistant to OXA and presented susceptibility to all the antimicrobial agents assayed. In all of them, the mec-A gene, the PVL gene, the gamma-hemolysin gene and the SCC cassette mec type IV gene were detected. With the OSSA and CA-ORSA isolates, all the non-beta-lactam antimicrobial agents assayed exhibited excellent in vitro activity. However, in the HA-ORSA isolates, only the old antimicrobial agents such as glycopeptides, doxyciclin, rifampin, and trimethoprim-sulfamethoxazole and the new antimicrobial agents LZD and TIG, presented good in vitro activity. The ORSA phenotype without accompanying resistance was highly predictive of CA-ORSA as confirmed by a positive SCC cassette mec type IV.

Heritability of thromboxane A2 and prostaglandin E2 biosynthetic machinery in a Spanish population

OBJECTIVE

Prostanoids play a critical role in clinical areas such as inflammation, thrombosis, immune response, and cancer. Although some studies suggest that there are genes that determine variability of some prostanoid-related phenotypes, the genetic influence on these traits has not been evaluated.

METHODS AND RESULTS

The relative contributions of genetic and environmental influences to the prostanoid biosynthetic pathway-related phenotypes, cyclooxygenase isoenzymes, microsomal-PGE-synthase-1 and TxA-synthase expression, and thromboxane-A(2) and prostaglandin-E(2) production by stimulated whole blood, were assessed in a sample of 308 individuals in 15 extended families. The effects of measured covariates (such as sex, age, and smoking), genes, and environmental variables shared by members of a household were quantified. Heritabilities ranging from 0.406 to 0.634 for enzyme expression and from 0.283 to 0. 751 for prostanoid production were found.

CONCLUSIONS

These results demonstrate clearly the importance of genetic factors in determining variation in phenotypes that are components of the prostanoid biosynthetic pathways. The presence of such strong genetic effects suggest that it will be possible to localize previously unknown genes that influence quantitative variation in these phenotypes, some of which affect multiple aspects of cell biology, with important clinical implications.

[Effect of posture on spinal cord stimulation in patients with chronic pain syndromes: analysis of energy requirements in different patient postures]

BACKGROUND AND OBJECTIVE

Patients being treated with spinal cord stimulation for chronic pain complain of variable paresthesias, particularly in relation to changes in posture. Such changes affect the great majority of patients with implantable pulse generators, requiring them to use the external programmer for avoidance of painful paresthesias or even to disconnect the generator, leading to loss of pain relief. The aim of this study was to determine the relationship between the pulse charge needed for stimulation and the patient's different postures.

MATERIAL AND METHODS

Observational study of 70 patients treated with spinal cord stimulation in the following postures and situations: decubitus position, standing, seated, and walking. With the patients standing, we analyzed the thresholds of perception, pain, and pain relief, as well as the therapeutic range. Studies were performed in all patients. Later, data were analyzed by anatomical positioning of the stimulator (cervical, thoracic, sacral, occipital, or subcutaneous).

RESULTS

In the analysis of the therapeutic range in the overall group we identified statistically significant differences between decubitus and standing positions and between decubitus position and walking. At the level of the thoracic spine differences were identified between all positions except between standing and walking and between seated and decubitus positions. At the level of the cervical spine, no significant differences were detected. Analysis of the pulse charge showed a significant difference in the decubitus position, in which less charge was needed to achieve satisfactory stimulation. When electrodes implanted at the cervical and thoracic levels were compared, differences were found between standing and seated positions (P=.04) but none between decubitus position or walking and the other positions.

CONCLUSION

Stimulation systems are not currently designed to adapt to changes in distance between the electrodes and nerve fibers. Improvements are required in this respect.