A novel workflow combining plaque imaging,plaque and plasma proteomics identifies biomarkers of human coronary atherosclerotic plaque disruption

Background

Atherosclerotic plaque rupture is the culprit event which underpins most acute vascular syndromes such as acute myocardial infarction. Novel biomarkers of plaque rupture could improve biological understanding and clinical management of patients presenting with possible acute vascular syndromes but such biomarker(s) remain elusive. Investigation of biomarkers in the context of de novo plaque rupture in humans is confounded by the inability to attribute the plaque rupture as the source of biomarker release, as plaque ruptures are typically associated with prompt down-stream events of myocardial necrosis and systemic inflammation.

Methods

We developed a novel approach to identify potential biomarkers of plaque rupture by integrating plaque imaging, using optical coherence tomography, with both plaque and plasma proteomic analysis in a human model of angioplasty-induced plaque disruption.

Results

We compared two pairs of coronary plaque debris, captured by a FilterWire Device, and their corresponding control samples and found matrix metalloproteinase 9 (MMP9) to be significantly enriched in plaque. Plaque contents, as defined by optical coherence tomography, affect the systemic changes of MMP9. Disruption of lipid-rich plaque led to prompt elevation of plasma MMP9, whereas disruption of non-lipid-rich plaque resulted in delayed elevation of plasma MMP9. Systemic MMP9 elevation is independent of the associated myocardial necrosis and systemic inflammation (measured by Troponin I and C-reactive protein, respectively). This information guided the selection of a subset of subjects of for further label free proteomics analysis by liquid chromatography tandem mass spectrometry (LC–MS/MS). We discovered five novel, plaque-enriched proteins (lipopolysaccharide binding protein, Annexin A5, eukaryotic translocation initiation factor, syntaxin 11, cytochrome B5 reductase 3) to be significantly elevated in systemic circulation at 5 min after plaque disruption.

Conclusion

This novel approach for biomarker discovery in human coronary artery plaque disruption can identify new biomarkers related to human coronary artery plaque composition and disruption.

     

Distribution of the Transposable Element Minos in the Genus Drosophila

We analyzed 28 species of the genus Drosophilafor the presence of the Tc1-like transposable element Minosusing Southern blot hybridization under high stringency conditions. The Minostransposon was found in members of both the Drosophilaand the Sophophorasubgenus showing a distribution that is wider if compared to other well-studied Drosophilatransposons such as the Pelement, hoboand mariner. The presence of Minos-hybridizing sequences was discontinuous in the Sophophorasubgenus, especially in the melanogasterspecies group. Using the Polymerase Chain Reaction we amplified a portion corresponding to the putative Minostransposase from different Drosophilaspecies. Cloning and sequence analysis of randomly selected Minoscopies from D. mojavensisis, D. saltansand D. willistonisupports the idea that event(s) of horizontal transfer may have contributed to the spreading of this transposon in the Drosophilagenus. This revised version was published online in July 2006 with corrections to the Cover Date.     

Lipid peroxidation and inguinal hernia repair. Tension-free vs. Andrews technique

AIM OF THE STUDY: To evaluate the early effect of inguinal hernia repair by the tension-free method compared to the conventional Andrew's technique on lipid peroxidation. PATIENTS-METHODS: Thirty-four patients subjected to elective hernia repair were enrolled in the study divided in two groups. Group A (n=18) underwent hernia repair by the tension-free method using a polypropylene mesh. Group B (n=16) underwent hernia repair by the Andrew's technique (i.e. a modification of the Bassini's technique). Venous blood samples were drawn preoperatively and at 12, 24 and 48 h postoperatively. Malondialdehyde (MDA) was estimated by the thiobarbiturate assay. RESULTS: Neutrophil counts were significantly higher in patients of group B compared to group A at 12 and 48 h postoperatively. Concentrations of fibrinogen were similar between the two groups. MDA was significantly higher in patients of group B hours compared to group A at 12, 24 and 48 h postoperatively. Positive correlation was found between neutrophil counts and MDA at 12 h (r: +0.43, P: 0.015) and 48 h (r: +0.496, P: 0.005) but not at 24 h. No correlation was found between serum fibrinogen and MDA. CONCLUSION: Hernia repair by the Andrews's technique elicits a sustained triggering of lipid peroxidation, compared to the tension-free method.     

Insect population control using female specific pro-drug activation

A system for population control of insects is proposed. It is based on transgenic insects expressing an enzyme which converts an inactive pro-drug into an active, toxic form. A model system is presented which relies on transposon-mediated integration of a bacterial cytosine deaminase (CD) gene into the genome of Drosophila melanogaster. We demonstrate female-specific sterility and transgene-dependent lethality when flies carrying the CD gene under a Drosophila female-specific promoter/enhancer are treated with 5-Fluorocytosine, a low-toxicity nucleoside analogue which is converted to toxic 5-Fluorouracil by the enzyme. The approach can be used with existing pro-insecticides and appropriate converting enzymes in combination with established mass rearing technology, for targeted, environmentally acceptable control of insects of economic and public health importance.     

Ultrastructural effects of Clostridium difficile toxin B on smooth muscle cells and fibroblasts

The mechanism by which Clostridium difficile toxin B causes cells in culture to round was investigated. Cultured human lung fibroblasts and rabbit aortic smooth muscle cells were treated with partially purified or purified toxin B and monitored by light and transmission electron microscopy (TEM). Both preparations caused progressive cell rounding which correlated with disorganization of actin-containing myofilament bundles. Thin myofilaments became fragmented and finally disappeared (after 24 h) and dense bodies became more prominent, while all other organelles appeared unaffected.     

The Relation between Geometry and Time in Mental Actions

Mental imagery is a cognitive tool that helps humans take decisions by simulating past and future events. The hypothesis has been advanced that there is a functional equivalence between actual and mental movements. Yet, we do not know whether there are any limitations to its validity even in terms of some fundamental features of actual movements, such as the relationship between space and time. Although it is impossible to directly measure the spatiotemporal features of mental actions, an indirect investigation can be conducted by taking advantage of the constraints existing in planar drawing movements and described by the two-thirds power law (2/3PL). This kinematic law describes one of the most impressive regularities observed in biological movements: movement speed decreases when curvature increases. Here, we compared the duration of identical actual and mental arm movements by changing the constraints imposed by the 2/3PL. In the first two experiments, the length of the trajectory remained constant, while its curvature (Experiment 1) or its number of inflexions (Experiment 2) was manipulated. The results showed that curvature, but not the number of inflexions, proportionally and similarly affected actual and mental movement duration, as expected from the 2/3PL. Two other control experiments confirmed that the results of Experiment 1 were not attributable to eye movements (Experiment 3) or to the perceived length of the displayed trajectory (Experiment 4). Altogether, our findings suggest that mental movement simulation is tuned to the kinematic laws characterizing actions and that kinematics of actual and mental movements is completely specified by the representation of their geometry.     

Length polymorphism in the threonine-glycine-encoding repeat region of theperiod gene inDrosophila

Summary Single-fly polymerase chain reaction amplification and direct DNA sequencing revealed high levels of length polymorphism in the threonine-glycine encoding repeat region of theperiod (per) gene in natural populations ofDrosophila melanogaster. DNA comparison of two alleles of identical lengths gave a high number of synonymous substitutions suggesting an ancient time of separation. However detailed examination of the sequences of different Thr-Gly length variants indicated that this divergence could be understood in terms of four deletion/insertion events. InDrosophila pseudoobscura a length polymorphism is observed in a five-amino acid degenerate repeat, which corresponds tomelanogaster's Thr-Gly domain. In spite of the differences betweenD. melanogaster andD. pseudoobscura in the amino acid sequence of the repeats, the predicted secondary structures suggest evolutionary and mechanistic constraints on theper protein of these two species.