Effect of transforming growth factor-ß1 (TGF-ß1) released from a scaffold on chondrogenesis in an osteochondral defect model in the rabbit

Articular cartilage repair might be stimulated by the controlled delivery of therapeutic factors. We tested the hypotheses whether TGF-ß1 can be released from a polymeric scaffold over a prolonged period of time in vitro and whether its transplantation modulates cartilage repair in vivo. Unloaded control or TGF-ß1 poly(ether-ester) copolymeric scaffolds were applied to osteochondral defects in the knee joints of rabbits. In vitro, a cumulative dose of 9 ng TGF-ß1 was released over 4 weeks. In vivo, there were no adverse effects on the synovial membrane. Defects treated with TGF-ß1 scaffolds showed no significant difference in individual parameters of chondrogenesis and in the average cartilage repair score after 3 weeks. There was a trend towards a smaller area (42.5 %) of the repair tissue that stained positive for safranin O in defects receiving TGF-ß1 scaffolds. The data indicate that TGF-ß1 is released from emulsioncoated scaffolds over a prolonged period of time in vitro and that application of these scaffolds does not significantly modulate cartilage repair after 3 weeks in vivo. Future studies need to address the importance of TGF-ß1 dose and release rate to modulate chondrogenesis

Metabolic analysis of the interaction between plants and herbivores

Insect herbivores by necessity have to deal with a large arsenal of plant defence metabolites. The levels of defence compounds may be increased by insect damage. These induced plant responses may also affect the metabolism and performance of successive insect herbivores. As the chemical nature of induced responses is largely unknown, global metabolomic analyses are a valuable tool to gain more insight into the metabolites possibly involved in such interactions. This study analyzed the interaction between feral cabbage (Brassica oleracea) and small cabbage white caterpillars (Pieris rapae) and how previous attacks to the plant affect the caterpillar metabolism. Because plants may be induced by shoot and root herbivory, we compared shoot and root induction by treating the plants on either plant part with jasmonic acid. Extracts of the plants and the caterpillars were chemically analysed using Ultra Performance Liquid Chromatography/Time of Flight Mass Spectrometry (UPLCT/MS). The study revealed that the levels of three structurally related coumaroylquinic acids were elevated in plants treated on the shoot. The levels of these compounds in plants and caterpillars were highly correlated: these compounds were defined as the ‘metabolic interface’. The role of these metabolites could only be discovered using simultaneous analysis of the plant and caterpillar metabolomes. We conclude that a metabolomics approach is useful in discovering unexpected bioactive compounds involved in ecological interactions between plants and their herbivores and higher trophic levels.

Identification of Biologically Relevant Compounds in Aboveground and Belowground Induced Volatile Blends

Plants under attack by aboveground herbivores emit complex blends of volatile organic compounds (VOCs). Specific compounds in these blends are used by parasitic wasps to find their hosts. Belowground induction causes shifts in the composition of aboveground induced VOC blends, which affect the preference of parasitic wasps. To identify which of the many volatiles in the complex VOC blends may explain parasitoid preference poses a challenge to ecologists. Here, we present a case study in which we use a novel bioinformatics approach to identify biologically relevant differences between VOC blends of feral cabbage (Brassica oleracea L.). The plants were induced aboveground or belowground with jasmonic acid (JA) and shoot feeding caterpillars (Pieris brassicae or P. rapae). We used Partial Least Squares—Discriminant Analysis (PLSDA) to integrate and visualize the relation between plant-emitted VOCs and the preference of female Cotesia glomerata. Overall, female wasps preferred JA-induced plants over controls, but they strongly preferred aboveground JA-induced plants over belowground JA-induced plants. PLSDA revealed that the emission of several monoterpenes was enhanced similarly in all JA-treated plants, whereas homoterpenes and sesquiterpenes increased exclusively in aboveground JA-induced plants. Wasps may use the ratio between these two classes of terpenes to discriminate between aboveground and belowground induced plants. Additionally, it shows that aboveground applied JA induces different VOC biosynthetic pathways than JA applied to the root. Our bioinformatic approach, thus, successfully identified which VOCs matched the preferences of the wasps in the various choice tests. Additionally, the analysis generated novel hypotheses about the role of JA as a signaling compound in aboveground and belowground induced responses in plants

Differences in Volatile Profiles of Turnip Plants Subjected to Single and Dual Herbivory Above- and Belowground

Plants attacked by herbivorous insects emit volatile organic compounds that are used by natural enemies to locate their host or prey. The composition of the blend is often complex and specific. It may vary qualitatively and quantitatively according to plant and herbivore species, thus providing specific information for carnivorous arthropods. Most studies have focused on simple interactions that involve one species per trophic level, and typically have investigated the aboveground parts of plants. These investigations need to be extended to more complex networks that involve multiple herbivory above- and belowground. A previous study examined whether the presence of the leaf herbivore Pieris brassicae on turnip plants (Brassica rapa subsp. rapa) influences the response of Trybliographa rapae, a specialist parasitoid of the root feeder Delia radicum. It showed that the parasitoid was not attracted by volatiles emitted by plants under simultaneous attack. Here, we analyzed differences in the herbivore induced plant volatile (HIPV) mixtures that emanate from such infested plants by using Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA). This multivariate model focuses on the differences between odor blends, and highlights the relative importance of each compound in an HIPV blend. Dual infestation resulted in several HIPVs that were present in both isolated infestation types. However, HIPVs collected from simultaneously infested plants were not the simple combination of volatiles from isolated forms of above- and belowground herbivory. Only a few specific compounds characterized the odor blend of each type of damaged plant. Indeed, some compounds were specifically induced by root herbivory (4-methyltridecane and salicylaldehyde) or shoot herbivory (methylsalicylate), whereas hexylacetate, a green leaf volatile, was specifically induced after dual herbivory. It remains to be determined whether or not these minor quantitative variations, within the background of more commonly induced odors, are involved in the reduced attraction of the root feeder’s parasitoid. The mechanisms involved in the specific modification of the odor blends emitted by dual infested turnip plants are discussed in the light of interferences between biosynthetic pathways linked to plant responses to shoot or root herbivory

Evaluation of multi-exponential curve fitting analysis of oxygen-quenched phosphorescence decay traces for recovering microvascular oxygen tension histograms

Although it is generally accepted that oxygen-quenched phosphorescence decay traces can be analyzed using the exponential series method (ESM), its application until now has been limited to a few (patho)physiological studies, probably because the reliability of the recovered oxygen tension (pO2) histograms has never been extensively evaluated and lacks documentation. The aim of this study was, therefore, to evaluate the use of the ESM to adequately determine pO2 histograms from phosphorescence decay traces. For this purpose we simulated decay traces corresponding to uni- and bimodal pO2 distributions and recovered the pO2 histograms at different signal-to-noise ratios (SNRs). Ultimately, we recovered microvascular pO2 histograms measured in the rat kidney in a model of endotoxemic shock and fluid resuscitation and showed that the mean microvascular oxygen tension, 〈pO2〉, decreased after induction of endotoxemia and that after 2 h of fluid resuscitation, 〈pO2〉 remained low, but the hypoxic peak that had arisen during endotoxemia was reduced. This finding illustrates the importance of recovering pO2 histograms under (patho)physiological conditions. In conclusion, this study has characterized how noise affects the recovery of pO2 histograms using the ESM and documented the reliability of the ESM for recovering both low- and high-pO2 distributions for SNRs typically found in experiments. This study might therefore serve as a frame of reference for investigations focused on oxygen (re)distribution during health and disease and encourage researchers to (re-)analyze data obtained in (earlier) studies possibly revealing new insights into complex disease states and treatment strategies

Posaconazole inhibits dengue virus replication by targeting oxysterol-binding protein

Dengue virus (DENV) is associated with an estimated 390 million infections per year, occurring across approximately 100 countries in tropical and sub-tropical regions. To date, there are no antiviral drugs or specific therapies to treat DENV infection. Posaconazole and itraconazole are potent antifungal drugs that inhibit ergosterol biosynthesis in fungal cells, but also target a number of human proteins. Here, we show that itraconazole and posaconazole have antiviral activity against DENV. Posaconazole inhibited replication of multiple serotypes of DENV and the related flavivirus Zika virus, and reduced viral RNA replication, but not translation of the viral genome. We used a combination of knockdown and drug sensitization assays to define the molecular target of posaconazole that mediates its antiviral activity. We found that knockdown of oxysterol-binding protein (OSBP) inhibited DENV replication. Moreover, knockdown of OSBP, but not other known targets of posaconazole, enhanced the inhibitory effect of posaconazole. Our findings imply OSBP as a potential target for the development of antiviral compounds against DENV

Cholestasis is associated with hepatic microvascular dysfunction and aberrant energy metabolism before and during ischemia-reperfusion

The aim was to investigate the impact of ischemia-reperfusion (I/R) on intrahepatic oxidative stress, oxidative phosphorylation, and nucleotide metabolism in relation to liver damage and inflammation in cholestatic rats to elucidate the molecular mechanisms responsible for post-I/R pathogenesis during cholestasis. Pre-I/R cholestatic livers exhibited mild hepatopathology in the form of oxidative/nitrosative stress, perfusion defects, necrosis and apoptosis, inflammation, and fibrosis. Plasma bilirubin concentration in cholestatic livers was 190 μM. I/R in cholestatic livers exacerbated hepatocellular damage and leukocyte infiltration. However, myeloperoxidase activity in neutrophils at 6 h reperfusion was not elevated in cholestatic livers compared to pre-I/R levels and to control (Ctrl) livers. At 6 h reperfusion, cholestatic livers exhibited severe histological damage, which was absent in Ctrl livers. Despite a lower antioxidative capacity after I/R, no cardiolipin peroxidation and equivalent reduced glutathione/oxidized glutathione ratios and Hsp70 levels were found in cholestatic livers versus Ctrls. Bilirubin acted as a potent and protective antioxidant. Postischemic resumption of oxidative phosphorylation in Ctrl livers proceeded rapidly and encompassed reactive hyperemia, which was significantly impaired in cholestatic livers owing to extensive vasoconstriction and perfusion defects. Normalization of intrahepatic energy status and nucleotide-based metabolic cofactors was delayed in cholestatic livers during reperfusion. Innovation and Cholestatic livers possess sufficient antioxidative capacity to ameliorate radical-mediated damage during I/R. I/R-induced damage in cholestatic livers is predominantly caused by microvascular perfusion defects rather than exuberant oxidative/nitrosative stress. The forestalled rate of oxidative phophorylation and recovery of bioenergetic and possibly metabolic parameters during the early reperfusion phase are responsible for extensive liver damag

Noninvasive cardiac output monitoring during exercise testing: Nexfin pulse contour analysis compared to an inert gas rebreathing method and respired gas analysis

Exercise testing is often used to assess cardiac function during physical exertion to obtain diagnostic information. However, this procedure is limited to measuring the electrical activity of the heart using electrocardiography and intermittent blood pressure (BP) measurements and does not involve the continuous assessment of heart functioning. In this study, we compared continuous beat-to-beat pulse contour analysis to monitor noninvasive cardiac output (CO) during exercise with inert gas rebreathing and respired gas analysis. Nineteen healthy male volunteers were subjected to bicycle ergometry testing with increasing workloads. Cardiac output was deter- mined noninvasively by continuous beat-to-beat pulse contour analysis (Nexfin) and by inert gas rebreathing, and estimated using the respired gas analysis method. The effects of the rebreathing maneuver on heart rate (HR), stroke volume (SV), and CO were evaluated. The CO values derived from the Nexfin- and inert gas rebreathing methods were well correlated (r = 0.88, P < 0.01) and the limits of agreement were 30.3% with a measurement bias of 0.4 ± 1.8 L/min. Nexfin- and respired gas analysis-derived CO values correlated even better (r = 0.94, P < 0.01) and the limits of agreement were 21.5% with a measurement bias of -0.70 ± 1.6 L/min. At rest, the rebreathing maneuver increased HR by 13 beats/min (P < 0.01), SV remained unaffected (P = 0.7), while CO increased by 1.0 L/min (P < 0.01). Rebreathing did not affect these parameters during exercise. Nexfin continuous beat-to-beat pulse contour analysis is an appropriate method for noninvasive assessment of CO during exercis