High glucose levels reduce fatty acid oxidation and increase triglyceride accumulation in human placenta

Placentas of women with gestational diabetes mellitus (GDM) exhibit an altered lipid metabolism. The mechanism by which GDM is linked to alterations in placental lipid metabolism remains obscure. We hypothesized that high glucose levels reduce mitochondrial fatty acid oxidation (FAO) and increase triglyceride accumulation in human placenta. To test this hypothesis, we measured FAO, fatty acid esterification, de novo fatty acid synthesis, triglyceride levels, and carnitine palmitoyltransferase activities (CPT) in placental explants of women with GDM or no pregnancy complication. In women with GDM, FAO was reduced by ~30% without change in mitochondrial content, and triglyceride content was threefold higher than in the control group. Likewise, in placental explants of women with no complications, high glucose levels reduced FAO by ~20%, and esterification increased linearly with increasing fatty acid concentrations. However, de novo fatty acid synthesis remained unchanged between high and low glucose levels. In addition, high glucose levels increased triglyceride content approximately twofold compared with low glucose levels. Furthermore, etomoxir-mediated inhibition of FAO enhanced esterification capacity by ~40% and elevated triglyceride content 1.5-fold in placental explants of women, with no complications. Finally, high glucose levels reduced CPT I activity by ~70% and phosphorylation levels of acetyl-CoA carboxylase by ~25% in placental explants of women, with no complications. We reveal an unrecognized regulatory mechanism on placental fatty acid metabolism by which high glucose levels reduce mitochondrial FAO through inhibition of CPT I, shifting flux of fatty acids away from oxidation toward the esterification pathway, leading to accumulation of placental triglycerides. © 2013 the American Physiological Society.This study was supported by a grant from the Carlos III Health Institute (CP08/00106), the Spanish Ministry of Science and Innovation (SAF2009-11282), and the FP7-PEOPLE-2009-RG (PIRG06-GA-2009-25369) to G. Perdomo; a grant from the Consejería de Salud, Junta de Andalucía (N°0269/05.2005) to J. L. Bartha; and grant from the Carlos III Health Institute (PI11/00676) to F. Bugatto.Peer Reviewe

Combating virulence of Gramnegative bacilli by OmpA inhibition

Preventing the adhesion of pathogens to host cells provides an innovative approach to tackling multidrug-resistant bacteria. In this regard, the identifcation of outer membrane protein A (OmpA) as a key bacterial virulence factor has been a major breakthrough. The use of virtual screening helped us to identify a cyclic hexapeptide AOA-2 that inhibits the adhesion of Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli to host cells and the formation of bioflm, thereby preventing the development of infection in vitro and in a murine sepsis peritoneal model. Inhibition of OmpA ofers a strategy as monotherapy to address the urgent need for treatments for infections caused by Gram-negative bacilli.Instituto de Salud Carlos III, Ministerio de Economía y Competitividad REIPI RD12/0015/0001Unión Europea ES P201431400Ministerio de Economía y Competitividad CP15/01358Junta de Andalucía CTS-6173/12 y 2014LLAV-00064Junta de Andalucía PI12–006

Changes in the Serotype Distribution of Streptococcus Pneumoniae Causing Otitis Media After PCV13 Introduction in Spain

One of the beneficial effects of pneumococcal conjugate vaccines (PCVs) has been a decrease in the incidence of non-invasive infections, such as otitis media (OM) caused by vaccine serotypes. In this study, we analyzed the epidemiology of pneumococcal OM before and after PCV13 introduction in 2010. Between 2008 and 2016, the middle ear exudates from 2653 children under 14 years of age with OM were studied in two Spanish provinces (Gipuzkoa and Barcelona), and S. pneumoniae was isolated in 235 (8.9%) of cases. The 204 available isolates were serotyped and distributed in three 3-year periods: one before and two after PCV13 introduction (early and late post-PCV13). A significant decrease in the rate of OM caused by S. pneumoniae was observed mainly due to a decrease in infections caused by all PCV13 serotypes, although exceptions were observed including the persistence of serotype 3 in Gipuzkoa and a weak re-emergence of serotype 19F in both regions. The rate and diversity of non-PCV13 serotypes increased in both regions and an emerging clone causing OM was detected in each region: serotype 23B ST2372 in Gipuzkoa and serotype 11A ST838/ST6521 in Barcelona. The introduction of PCV13 has been followed by a change in the epidemiology of pneumococcal OM, with a decrease in the rate of vaccine serotypes accompanied by an increase in the diversity of non-vaccine serotype and the clonal spreading of different single clones in each region.JMM was funded in part by the Centro de Investigacion Biomedica en Red de Enfermedades Respiratorias (CIBERES-26). CMA was funded in part by the Centro de Investigacion Biomedica en Red de de Epidemiologia y Salud Publica (CIBERESP-57). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This work was funded in part by the Centro de Investigacion Biomedica en Red de Enfermedades Respiratorias (CIBERES-26) and de Epidemiologia y Salud Publica (CIBERESP-57)

Synergistic Activity of Niclosamide in Combination With Colistin Against Colistin-Susceptible and Colistin-Resistant Acinetobacter baumannii and Klebsiella pneumoniae

Colistin is among the few antibiotics effective against multidrug-resistant Acinetobacter baumannii and Klebsiella pneumoniae clinical isolates. However, in the last few years, colistin-resistant A. baumannii and K. pneumoniae strains have emerged. Therefore, combination therapies, between colistin and other old drugs, restoring the activity of colistin are required. The main objective of this study was to analyse the activity of niclosamide, an anthelmintic drug, in combination with colistin against colistin-susceptible (Col-S) and colistin-resistant (Col-R) A. baumannii and K. pneumoniae. The MIC were determined by microdilution assay and the time-kill curves were performed. The zeta potential of Col-S and Col-R of A. baumannii and K. pneumoniae in presence of niclosamide was assessed. Niclosamide in combination with colistin showed improved activity against Col-S and Col-R A. baumannii and K. pneumoniae. Time-killing curves showed synergic activity between niclosamide and colistin against Col-S and Col-R A. baumannii and K. pneumoniae, especially when niclosamide or colistin was added for second time at 4 h of the 24 h killing curve. Col-R A. baumannii and K. pneumoniae in presence of niclosamide exhibited a greater negative charge (−34.95 ± 0.35 mV and −38.85 ± 0.92 mV; P < 0.05) than Col-R A. baumannii and K. pneumoniae in absence of niclosamide (−26.85 ± 3.65 mV and −35.27 ± 0.72 mV). These data suggest that niclosamide might be combined with colistin, being a potential alternative for treatment of Col-R Gram-negative bacilli infections.Instituto de Salud Carlos IIIProyectos de Investigacion en Salud PI16/01378Ministerio de Economía y Competitividad CP15/0135

Targeted delivery of HGF to the skeletal muscle improves glucose homeostasis in diet-induced obese mice

Hepatocyte growth factor (HGF) is a cytokine that increases glucose transport ex vivo in skeletal muscle. The aim of this work was to decipher the impact of whether conditional overexpression of HGF in vivo could improve glucose homeostasis and insulin sensitivity in mouse skeletal muscle. Following tetracyclin administration, muscle HGF levels were augmented threefold in transgenic mice (SK-HGF) compared to control mice without altering plasma HGF levels. In conditions of normal diet, SK-HGF mice showed no differences in body weight, plasma triglycerides, blood glucose, plasma insulin and glucose tolerance compared to control mice. Importantly, obese SK-HGF mice exhibited improved whole-body glucose tolerance independently of changes in body weight or plasma triglyceride levels compared to control mice. This effect on glucose homeostasis was associated with significantly higher (∼80 %) levels of phosphorylated protein kinase B in muscles from SK-HGF mice compared to control mice. In conclusion, muscle expression of HGF counteracts obesity-mediated muscle insulin resistance and improves glucose tolerance in mice.This study was supported by a grant from ISCIII (CP08/00106), MINECO (SAF2009-11282) and FP7-PEOPLE-2009-RG (PIRG06-GA-2009-25369) to GP; a grant from MINECO (RYC-2011-08101) to IC; and grants from the NIH R-01 (DK067351 and DK077096) to AGO.Peer Reviewe

ERIC/RCS Report: Individualized Reading

Preventing the adhesion of pathogens to host cells provides an innovative approach to tackling multidrug-resistant bacteria. In this regard, the identification of outer membrane protein A (OmpA) as a key bacterial virulence factor has been a major breakthrough. The use of virtual screening helped us to identify a cyclic hexapeptide AOA-2 that inhibits the adhesion of Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli to host cells and the formation of biofilm, thereby preventing the development of infection in vitro and in a murine sepsis peritoneal model. Inhibition of OmpA offers a strategy as monotherapy to address the urgent need for treatments for infections caused by Gram-negative bacilli.This study was supported by the Consejería de Salud y Bienestar (grant PI12–0069), the Consejería de Economia, Innovación, Ciencia y Empleo (grants CTS-6173/12, and 2014LLAV-00064) of Andalusia, Spain, and by Plan Nacional de I + D + i 2008–2011 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Economía y Competitividad, Spanish Network for Research in Infectious Diseases (REIPI RD12/0015/0001) co-financed by European Development Regional Fund “A way to achieve Europe”. This work led to the provisional patent application ES P201431400. Y. Smani is supported by the Subprograma Miguel Servet Tipo I from the Ministerio de Economía y Competitividad of Spain [CP15/01358]. IRB Barcelona is the recipient of a Severo Ochoa Award of Excellence from MINECO (Government of Spain).Peer reviewe

Actividad in vitro e in vivo del inhibidor de la proteína de la membrana externa A (OmpA) frente a Acinetobacter baumannii sensible y resistente a colistina

Motivación: El tratamiento ante la infección por Acinetobacter baumannii se ha hecho difícil debido al aumento de la tasa de resistencia antibiótica, incluso a colistina que es el último recurso terapéutico (1). Recientemente, se describió que A. baumannii deficiente en el gen ompA presenta mayor sensibilidad a varios antibióticos incluso la colistina (2,3). Por lo tanto, OmpA podría ser una buena diana terapéutica para aumentar la sensibilidad de este patógeno a colistina. El objetivo del estudio es determinar la actividad in vitro de un péptido inhibidor de OmpA (MV5) frente a cepas sensible (Col-S) y resistente (Col-R) a colistina de A. baumannii y evaluar la eficacia terapéutica de MV5 en combinación con colistina in vivo.Métodos: Se utilizaron 2 cepas de A. baumannii, una Col-S y otra Col-R. Se determinó la concentración mínima inhibitoria (CMI) de colistina de estas cepas en presencia y en ausencia de MV5. Se realizaron curvas de crecimiento bajo distintas condiciones de colistina y MV5. Para estudiar el mecanismo de actuación del MV5, se efectuó la extracción de proteínas de la membrana externa (OMPs) y se analizó el perfil proteíco mediante SDS-PAGE de ambas cepas en presencia y ausencia de MV5. Se realizaron ensayos en modelo experimental murino de sepsis peritoneal por la cepa Col-S, tratados o no con MV5 (10 mg/kg/d) y colistina (10 mg/kg/d) durante 3 días, determinando la carga bacteriana en bazo y pulmón, la bacteriemia, así como la supervivencia.Resultados: Se observó una disminución en la CMI de colistina de ambas cepas en presencia de MV5. Las curvas de crecimiento mostraron una actividad sinérgica in vitro de MV5 con colistina, apreciándose un descenso significativo del crecimiento bacteriano en el tratamiento combinado respecto al tratamiento solo con colistina. Al analizar el perfil de OMPs de las cepas Col-S y Col-R se observó la sobrexpresión de la proteína Omp25 cuando ambas cepas se trataron con MV5, indicando un posible mecanismo de resistencia a colistina adicional de A. baumannii. El tratamiento con MV5 en el modelo de sepsis peritoneal murina redujo significativamente la carga bacteriana en bazo y pulmón con respecto al control y el porcentaje de hemocultivo positivo, y hubo una mayor supervivencia.Conclusiones: Nuestros resultados muestran que el MV5 puede actuar en sinergia con colistina in vitro e in vivo, lo que ayudaría a resolver los problemas relacionados con el tratamiento contra A. baumannii resistentes a colistina

Synergistic Activity of Niclosamide in Combination With Colistin Against Colistin-Susceptible and Colistin-Resistant Acinetobacter baumannii and Klebsiella pneumoniae

Colistin is among the few antibiotics effective against multidrug-resistant Acinetobacter baumannii and Klebsiella pneumoniae clinical isolates. However, in the last few years, colistin-resistant A. baumannii and K. pneumoniae strains have emerged. Therefore, combination therapies, between colistin and other old drugs, restoring the activity of colistin are required. The main objective of this study was to analyse the activity of niclosamide, an anthelmintic drug, in combination with colistin against colistin-susceptible (Col-S) and colistin-resistant (Col-R) A. baumannii and K. pneumoniae. The MIC were determined by microdilution assay and the time-kill curves were performed. The zeta potential of Col-S and Col-R of A. baumannii and K. pneumoniae in presence of niclosamide was assessed. Niclosamide in combination with colistin showed improved activity against Col-S and Col-R A. baumannii and K. pneumoniae. Time-killing curves showed synergic activity between niclosamide and colistin against Col-S and Col-R A. baumannii and K. pneumoniae, especially when niclosamide or colistin was added for second time at 4 h of the 24 h killing curve. Col-R A. baumannii and K. pneumoniae in presence of niclosamide exhibited a greater negative charge (−34.95 ± 0.35 mV and −38.85 ± 0.92 mV; P < 0.05) than Col-R A. baumannii and K. pneumoniae in absence of niclosamide (−26.85 ± 3.65 mV and −35.27 ± 0.72 mV). These data suggest that niclosamide might be combined with colistin, being a potential alternative for treatment of Col-R Gram-negative bacilli infections.This study was supported by the Instituto de Salud Carlos III, Proyectos de Investigación en Salud (grant PI16/01378). YS is supported by the Subprograma Miguel Servet Tipo I from the Ministerio de Economía y Competitividad of Spain (CP15/01358).Peer reviewe

Synergistic activity of an OmpA inhibitor and colistin against colistin-resistant Acinetobacter baumannii: mechanistic analysis and in vivo efficacy

[Objectives] Preventing bacterial contact with host cells can provide an additional approach to tackling MDR Acinetobacter baumannii. Recently, we identified AOA-2 as a potential blocker of A. baumannii outer membrane protein A without presenting bactericidal activity. Here, we aimed to study whether AOA-2 can increase the activity of colistin against colistin-resistant A. baumannii in vitro and in vivo.[Methods] Reference and clinical A. baumannii strains susceptible and resistant to colistin (CST-S and CST-R) were used. Microdilution and time–kill curve assays were performed to determine the synergy between AOA-2 and colistin. SDS-PAGE assays with CST-S and CST-R outer membrane proteins and MALDI-TOF-TOF (MS-MS/MS) analysis were performed to determine the AOA-2 and colistin synergy mechanism. In a murine peritoneal sepsis model, the therapeutic efficacy of AOA-2 (10 mg/kg/24 h) in combination with a sub-optimal dose of colistin (10 mg/kg/24 h) against CST-R was evaluated by determining the bacterial load in tissues and blood, and mouse survival.[Results] We showed that AOA-2 increased the in vitro colistin susceptibility of reference and clinical CST-S and CST-R strains. This combination also enhanced their killing activity after 24 h of drug exposure. This synergy is mediated by the overexpression of Omp25. In vivo, the combination of AOA-2 with colistin significantly reduced the bacterial load in tissues and blood, and increased mouse survival, compared with colistin monotherapy.[Conclusions] We identified a novel class of antimicrobial agents that has proven to be effective in combination with colistin in an experimental model of severe infection by CST-R A. baumannii.This study was supported by the Consejería de Salud y Bienestar Social (PI12-0069), by the Consejería de Economía, Innovación, Ciencia y Empleo (CTS-6173/12) of Andalusia, Spain, by the Instituto de Salud Carlos III, Ministerio de Economía, Industria y Competitividad (PI15/01358), by Plan Nacional de I + D+i 2013‐2016 and Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Economía, Industria y Competitividad, Spanish Network for Research in Infectious Diseases (REIPI RD16/0016/0009), by Ministerio de Economía, Industria y Competitividad (Bio2016-75327-R) ‐ cofinanced by European Development Regional Fund ‘A way to achieve Europe’, Operative programme Intelligent Growth 2014‐2020, and by the Generalitat de Catalunya (XRB, 2017SGR0998 and 2014LLAV-00064). Y. S. is supported by the Subprograma Miguel Servet Tipo I from the Ministerio de Economía y Competitividad of Spain (CP15/01358). IRB Barcelona is the recipient of a Severo Ochoa Award of Excellence from MINECO (Government of Spain).Peer reviewe