Carmen Curutiu

Development of Scaffolds for Vascular Tissue Engineering: Biomaterial Mediated Neovascularization.

Cardiovascular diseases remain the leading cause of mortality or disabled quality of life for people over the world. The necessity of neovascularization is essential for re-establishing the tissue functions after a major lesion that occurs in patients with cardiovascular disorders, such as ischemia, atherosclerosis, diabetes, peripheral vascular disease and burn wounds. This review focuses on the recent data regarding the polymers and scaffolds that are used for improving neovascularization with emphasis on the biocompatibility and mechanisms involved in stem cells proliferation, migration, adherence, differentiation and organization in vascular networks. The newly emerging techniques used in conjugation of synthetic polymers with polysaccharides or proteins attempt to improve the biocompatibility of scaffolds, but the complex structures of blood vessels make their construction to remain a major challenge for the vascular tissue engineering.

Identification of Genetically Modified Foods

Modern biotechnology is trying to create new genetically modified (GM) foods that express useful traits, such as insect resistance, herbicide tolerance, infectious-agent resistance, and resistance to environmental changes. The traceability of GM organisms (GMOs) is ensured through the use of strategies and regulations based on molecular detection methods. These methods can be categorized as indirect (e.g., immunologic) or direct (e.g., genetic). Among these analytical methods, real-time PCR is considered as the “gold standard” technique. This chapter aims to discuss the advantages and disadvantages of these techniques and provide information on new technologies that offer high-throughput screening of GM foods. Furthermore, the sample collection and validation criteria presented highlight their crucial role in obtaining reliable results.

Aspects of Gut Microbiota and Immune System Interactions in Infectious Diseases, Immunopathology, and Cancer

The microbiota consists of a dynamic multispecies community of bacteria, fungi, archaea, and protozoans, bringing to the host organism a dowry of cells and genes more numerous than its own. Among the different non-sterile cavities, the human gut harbors the most complex microbiota, with a strong impact on host homeostasis and immunostasis, being thus essential for maintaining the health condition. In this review, we outline the roles of gut microbiota in immunity, starting with the background information supporting the further presentation of the implications of gut microbiota dysbiosis in host susceptibility to infections, hypersensitivity reactions, autoimmunity, chronic inflammation, and cancer. The role of diet and antibiotics in the occurrence of dysbiosis and its pathological consequences, as well as the potential of probiotics to restore eubiosis is also discussed.

Impact of Pseudomonas aeruginosa quorum sensing signaling molecules on adhesion and inflammatory markers in endothelial cells

Pseudomonas aeruginosa relies on the quorum sensing (QS) signaling system as a central regulator mechanism of virulence expression that contributes to the formation and maintenance of biofilms and tolerance to conventional antimicrobials. QS Signaling molecules (QSSMs) may be recognized and may function also within the host cells, being potentially involved in the progression of the infectious process. In this study we evaluate the expression of adhesion and inflammatory molecules in endothelial cells treated with P. aeruginosa QSSMs, in order to bring new insights on the mechanisms involved in the interaction of P. aeruginosa with host cells during the infectious process. Endothelial cells were stimulated with 20 µM of main P. aeruginosa QSSMs (OdDHL = N-(3-oxododecanoyl)-L-homoserine lactone, C4HSL = N-butyryl-L-homoserine lactone, PQS = 2-heptyl-3-hydroxy-4(1H)-quinolone and HHQ = 2-heptyl-4-quinolone). Adherence to endothelial cells, inert substratum and biofilm formation was evaluated. The expression of adhesion molecules (VE-cadherin, PECAM-1, ICAM-1, and P-selectin) and inflammatory response molecules (IL-1β, IL-6, TNFα, TGFβ, and eNOS) was assessed by qRT-PCR and flow cytometry. Our results showed that bacterial adherence to inert substratum and biofilm were decreased in the presence of all tested QSSMs. The adherence index of PAO1 laboratory strain to host cells was decreased between 10–40% in the presence of QSSMs, as compared to untreated control. Expression of eukaryotic cells adhesion molecules ICAM-1 and P-selectin was stimulated by QSSMs, whereas VE-cadherin and PECAM-1 levels were increased only by C4HSL. The inflammatory response of endothelial cells was also modulated, as observed by the modified expression of IL-1β (for C4HSL, PQS and HHQ), IL-6 (for C4HSL and HHQ), TNFα (for C4HSL and HHQ), TGFβ, and eNOS factors. Our results demonstrate that the main pseudomonadal QSSMs differentially modulate endothelial cells adhesion and proinflammatory cytokine expression. These observations provide new insights in the mechanisms by which different QSSMs activate endothelial cells and modulate the infectious process, and support the importance of recent studies aiming to develop anti-QS therapeutic strategies to fight against P. aeruginosa infections.

18 – Microbial biofilms from the aquatic ecosystems and water quality

In nature, bacteria generally exists in the biofilm state, consisting cells attached to each other and also to a surface, embedded in a protective matrix. The aquatic biofilms are complex and dynamic communities developed on all exposed interfaces of the respective ecosystems, with a considerable microbial biodiversity, composed of different species of bacteria, diatoms, and protozoa. Their structure is dependent on the species composition of the respective area microbiota, their microbial metabolism, and environmental conditions. Drinking water distribution systems are continuously exposed to a variable water flow, containing biodegradable organic substances and microorganisms, which originate either from the natural biofilms or from some incidents appeared in the distribution network. A major concern for water retailers is to maintain the quality of drinking water from the treatment plant to the tap water. The purpose of this chapter is to give an overview on the characteristics of microbial biofilms found in the aquatic ecosystems with a special focus on their both negative and beneficial roles for the water treatment and quality.

Beta-lactam and quinolone resistance markers in uropathogenic strains isolated from renal transplant recipients

Abstract Our objectives were to investigate the extended-spectrum beta-lactamases (ESBLs) and carbapenemases (CR) genetic determinants and to assess the association between ESBL production and quinolone resistance in bacterial strains isolated from renal transplant recipients with urinary tract infections. Material and methods: A number of 30 isolates were recovered from urine specimens of patients with renal transplant from October 2015 to March 2016. The isolates were analyzed for ESBL production using double disc synergy test and for CR production by the Hodge test. Phenotypically confirmed isolates were screened by PCR for the identification of ESBL, CR and fluoroquinolone resistance genes. Results: The 30 clinical bacterial strains isolated from urinary tract infections in renal transplant recipients were identified as Klebsiella pneumoniae (17), Pseudomonas aeruginosa (7), Morganella morganii (2), Escherichia coli (2), Edwardsiella tarda (1) and Enterobacter cloacae (1). Out of them, 22 isolates were ESBL producers and 20 multi-drug resistant (MDR) (i.e., 13 K. pneumoniae and 7 P. aeruginosa strains). More than half of the ESBL clinical strains (14/22, 63.63%) revealed at least one ESBL gene, the most frequent being blaCTX-M type (18/22, 81.81%), either alone (4/22, 18.18%) or in combination with another ESBL gene (17/22, 77.27%), followed by blaTEM (13/22, 59.09%). The blaOXA-48 was present in 10 isolates (33.33%). The most frequent association of ESBLs and CR genes (5/14, 35.71%) was revealed by blaCTX-M- blaTEM - blaOXA-48, encountered particularly among K. pneumoniae isolates (4/17, 23.52%). The qnrB gene was identified in five strains, i.e. one P. aeruginosa ESBL isolate (expressing the blaCTX-M gene) and four K. pneumoniae ESBL isolates (harboring the blaCTX-M - blaTEM genes combination). Conclusions: The uropathogenic strains isolated from renal transplant recipients exhibited high rates of MDR and beta-lactam resistance. The selective pressure exerted by quinolones could enable uropathogenic bacteria to acquire resistance to this class of antibiotics.

Preparation and Antimicrobial Activity of Inorganic Nanoparticles

Abstract Nanotechnology provides unique alternatives to control the biological and medical processes to achieve benefits for biology and medicine. Nanoparticles provide appealing properties such as high stability and the possibility of changing their surface characteristics very easily. Metal oxide nanoparticles are promising antimicrobial agents because they do not cause resistance and have good microbicidal activity. This review is focused on applications and properties of inorganic nanostructured materials and discusses the main advantages and risks of using different metal and metal oxide nanoparticles, such as silver nanoparticles, gold nanoparticles, zinc oxide nanoparticles, magnetite nanoparticles, and copper oxide nanoparticles as antimicrobial agents.

Applications of nanoscale drugs carriers in the treatment of chronic diseases

Nanomedicine plays an important role in the medical field for applications as drug delivery and diagnosis. The requirement for the development of multiple systems, which can precisely and specifically deliver the pharmaceutical agent into the desired site, has increased over the last decade. These systems have a great impact in medical fields, such as oncology, cardiology, and immunology. In this regard, smart drug delivery systems with response to stimuli, such as pH, temperature, light, ultrasounds, electrical, and magnetical fields have been developed. Many nanoparticles have been investigated for drug targeting as nanocarriers, including gold NPs, silver NPs, magnetic NPs, quantum dots, and mesoporous silica NPs.

Nanostructurated materials for prolonged and safe food preservation

Even though many food preservation methods have been developed over time, most of the current approaches impact the quality of foods and/or change the regular form and aspect. Recent studies on the field of food engineering and processing are focused on the development of alternative methods able to assure a prolonged and safe preservation in order to overcome the current inconvenience related with poor quality food. Food nanotechnology represents an emerging field that aims to revolutionize the global food system, with wide applications in food engineering, food nanosensing, development of nanostructured ingredients, food quality control, safety evaluation, food processing, and food packaging and preservation. This chapter reveals the main properties, advantages, and disadvantages of current preservation methods and highlights the potential implications of nanostructured materials and nanotechnology in the design of alternative preservation and packaging methods, to assure safe food storage and consumption. Moreover, recent advances regarding the development of smart materials and nanostructured preservatives for agri-food sector are also discussed.

Antibiotic Drug Delivery Systems for the Intracellular Targeting of Bacterial Pathogens

Intracellular bacterial pathogens are hard to treat because of the inability of conventional antimicrobial agents belonging to widely used classes, like aminoglycosides and β-lac‐ tams, fluoroquinolones, or macrolides to penetrate, accumulate, or be retained in the mammalian cells. The increasing problem of antibiotic resistance complicates more the treatment of the diseases caused by these agents. In many cases, the increase in therapeu‐ tic doses and treatment duration is accompanied by the occurrence of severe side effects. Taking into account the huge financial investment associated with bringing a new antibi‐ otic to the market and the limited lifetime of antibiotics, the design of drug delivery sys‐ tems to enable the targeting of antibiotics inside the cells, to improve their activity in different intracellular niches at different pH and oxygen concentrations, and to achieve a reduced dosage and frequency of administration could represent a prudent choice. An ideal drug delivery system should possess several properties, such as antimicrobial activ‐ ity, biodegradability, and biocompatibility, making it suitable for use in biomedical and pharmaceutical formulations. This approach will allow reviving old antibiotics rendered useless by resistance or toxicity, rescuing the last line therapy antibiotics by increasing the therapeutic index, widening the antimicrobial spectrum of antibiotics scaffolds that failed due to membrane permeability problems, and thus reducing the gap between in‐ creasingly drug-resistant pathogens and the development of new antibiotics. Different improved drug carriers have been developed for treating intracellular pathogens, includ‐ ing antibiotics loaded into liposomes, microspheres, polymeric carriers, and nanoplexes. The purpose of this chapter is to present the limitations of each class of antibiotics in tar‐ geting intracellular pathogens and the main research directions for the development of drug delivery systems for the intracellular release of antibiotics.