Application of vascular endothelial growth factor at different phases of intestinal ischemia/reperfusion: what are its effects on oxidative stress, inflammation and telomerase activity?

Background. Intestinal ischemic reperfusion injury (IRI) represents a great challenge in clinical practice, with high morbidity and mortality. Vascular endothelial growth factor (VEGF), asasignal protein, contributes tovasculogenesis and angiogenesis.Objectives. To evaluate the local effectiveness of VEGF following intestinal IRI and its relation with application time.Material and methods. Thirty Wistar albino rats were allocated to5 groups and underwent laparotomy. Thesuperior mesenteric arteries (SMA) were dissected in4 groups, while thecontrol group (GrC) underwent aresection ofsmall and large intestines. The VEGF group (Gr V) received VEGF following SMA dissection, with no further intervention, and theremaining 3 groups were subjected toischemia for 90min through occlusion ofSMA and reperfusion for 4h. Ischemic reperfusion group (Gr I/R) received no additional medication, while theremaining 2 groups received VEGF just before ischemia (Gr V+I/R) and during reperfusion (Gr I/R+V).Results. Both applications of VEGF caused decreases inplasma levels of interleukin6 (IL-6), tumor necrosis factor ? (TNF-?), intestinal malondialdehyde (MDA), oxidized glutathione, protein carbonyl levels, and increases inintestinal total glutathione and superoxide dismutase (SOD) levels. Telomerase activity, which disappeared for Gr I/R, was found to be elevated following both treatment groups. Similarly, the histopathological scores were found better for both treatment groups, but Gr V-I/R represented best outcomes.Conclusions. The findings of our study revealed that VEGF, applied either before ischemia or during reperfusion, iseffective onlocal damage following intestinal IRI. Byinterpreting thebiochemical analysis and histopathological findings, we conclude either treatment option to be considered according to the reason of intestinal IRI

Surface chemistry and morphology in single particle optical imaging

Biological nanoparticles such as viruses and exosomes are important biomarkers for a range of medical conditions, from infectious diseases to cancer. Biological sensors that detect whole viruses and exosomes with high specificity, yet without additional labeling, are promising because they reduce the complexity of sample preparation and may improve measurement quality by retaining information about nanoscale physical structure of the bio-nanoparticle (BNP). Towards this end, a variety of BNP biosensor technologies have been developed, several of which are capable of enumerating the precise number of detected viruses or exosomes and analyzing physical properties of each individual particle. Optical imaging techniques are promising candidates among broad range of label-free nanoparticle detectors. These imaging BNP sensors detect the binding of single nanoparticles on a flat surface functionalized with a specific capture molecule or an array of multiplexed capture probes. The functionalization step confers all molecular specificity for the sensor’s target but can introduce an unforeseen problem; a rough and inhomogeneous surface coating can be a source of noise, as these sensors detect small local changes in optical refractive index. In this paper, we review several optical technologies for label-free BNP detectors with a focus on imaging systems. We compare the surface-imaging methods including dark-field, surface plasmon resonance imaging and interference reflectance imaging. We discuss the importance of ensuring consistently uniform and smooth surface coatings of capture molecules for these types of biosensors and finally summarize several methods that have been developed towards addressing this challenge