Nanocomposite particles with improved microstructure for 3D culture systems and bone regeneration

Nano-apatite and gelatin-alginate hydrogel microparticles have been prepared by a one-step synthesis combined with electrostatic bead generation, for the reconstruction of bone defects. Based on the analysis of bone composition, architecture and embryonic intramembranous ossification, a bio-inspired fabrication has been developed. Accordingly, the mineral phase has been in situ synthesized, calcifying the hydrogel matrix while the latter was crosslinked, finally generating microparticles that can assemble into a bone defect to ensure interconnected pores. Although nano-apatite-biopolymer composites have been widely investigated, microstructural optimization to provide improved distribution and stability of the mineral is rarely achieved. The optimization of the developed method progressively resulted in two types of formulations (15P and 7.5P), with 15 and 7.5 (wt%) phosphate content in the initial precursor. The osteolytic potential was investigated using differentiated macrophages. A commercially available calcium phosphate bone graft substitute (Eurocer 400) was incorporated into the hydrogel, and the obtained composites were in vitro tested for comparison. The cytocompatibility of the microparticles was studied with mouse osteoblast-like cell line MC3T3-E1. Results indicated the best in vitro performance have been obtained for the sample loaded with 7.5P. Preliminary evaluation of biocompatibility into a critical size (3 mm) defect in rabbits showed that 7.5P nanocomposite is associated with newly formed bone in the proximity of the microparticles, after 28 days.

Improved antibacterial behavior of titanium surface with torularhodin-polypyrrole film

The problem of microorganisms attaching and proliferating on implants and medical devices surfaces is still attracting interest in developing research on different coatings based on antibacterial agents. The aim of this work is centered on modifying titanium (Ti) based implants surfaces through incorporation of a natural compound with antimicrobial effect, torularhodin (T), by means of a polypyrrole (PPy) film. This study tested the potential antimicrobial activity of the new coating against a range of standard bacterial strains: Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis and Pseudomonas aeruginosa. The morphology, physical and electrochemical properties of the synthesized films were assessed by SEM, AFM, UV-Vis, FTIR and cyclic voltammetry. In addition, biocompatibility of this new coating was evaluated using L929 mouse fibroblast cells. The results showed that PPy-torularhodin composite film acts as a corrosion protective coating with antibacterial activity and it has no harmful effect on cell viability.

[Perioperative immunologic changes in colorectal cancer patients]

The aim of the study was to investigate the perioperative immunological profile in colon cancer patients and possible correlations with disease. To investigate the changes in immune mediators profile induced by tumor resection, we assessed the serum levels of cytokines (IL-6, IL-8, IL-10, IFN-gamma, TNF-alpha), chemokines (MIP-1alpha, MCP-1, ENA-78) and growth factors (VEGF, bFGF) in colon cancer patients before, during and after surgery and compared the results with those measured for a group of healthy controls. We have used XMap profiling technology (Luminex) that allows simultaneous measurement of multiple parameters in small volumes of samples. Circulating levels of proinflammatory cytokines IL-1, IL-6, IL-8 and antiinflamatory cytokine IL-10 were elevated in cancer patients with respect to healthy controls. Before surgery, serum levels of MCP-1 and MIP-1alpha positively correlated with the levels of proinflammatory cytokines. During surgery, an increase in serum concentration of all determined mediators was noticed, with positive correlation between TNF-alpha, IL-8, MCP-1 and MIP-1alpha. Interestingly, these correlations were no more noticed one week after operation. Postoperatively, cytokines levels decreased as compared to those noticed before surgery, but still higher than in control group. These preliminary results suggest that both tumor and surgical act may influence immune mediators' network.

Bacterial extract cantastim activates macrophages via TLR-2

CANTASTIM is a second generation bacterial immunomodulator. The aim of this study was to examine the mechanism by which bacterial immunomodulator CANTASTIM induces production of inflammatory cytokines in monocytes/macrophages. Proinflammatory cytokines were induced in PMA-differentiated THP-1 cells by stimulation with TLR agonists and CANTASTIM in the presence or absence of anti-TLR blocking antibodies or isotype matched control antibodies. Also, RNA interference was used to knockdown TLR2 or TLR4 expression in PMA-differentiated THP-1 cells before stimulation. As expected, induction of TNF-alpha and IL-6 by TLR4 agonist LPS was inhibited in a significant manner by anti-TLR4 but not by anti-TLR2 antibody. Unexpectedly, treatment with anti-LR2 blocking antibody inhibited only IL-6 production induced by Pam3CSK4 while the level of TNF-alpha was unchanged. When cells were stimulated by TLR2 agonist heat-killed Listeria monocytogenes the release of TNF-alpha was significantly attenuated by anti-TLR2 antibodies. Silencing of TLR2 led to a statistically significant inhibition of TNF-alpha secretion induced by TLR2 agonist while siRNA silencing of TLR4 did not affect the response to TLR2 agonist. Cells exposed to CANTASTIM produced significant levels of pro-inflammatory cytokines but the levels were lower than LPS-stimulated cells. Production of both cytokines was inhibited by treatment with anti-TLR2 blocking antibody and not by anti-TLR4 antibody. Silencing of TLR2 led to a statistically significant inhibition of TNF-a secretion induced by CANTASTIM while silencing of TLR4 had no effect on the response to CANTASTIM. These results support the hypothesis that CANTASTIM may exert its immunomodulatory and adjuvant activities through interaction of its bacterial components with TLR2.

Serum levels of adipokines resistin and leptin in patients with colon cancer

Adipose tissue displays characteristics of an endocrine organ releasing a number of adipocyte-specific factors known as adipocytokines. It has been recently suggested that adipocytokines may play a role in pathogenesis and progression of certain cancers, in particular in colorectal cancer. The aim of this study was to investigate the association between several blood adipocytokine levels and clinicopathological characteristics of colon cancer patients undergoing surgery. The study group comprised of 29 patients who underwent surgical resection for colon cancer at Emergency University Hospital Bucharest and 27 healthy volunteers. The serum levels of adipocytokines were measured using multianalyte xMap profiling technology (Luminex). Resistin levels were significantly higher in colon cancer patients while leptin serum levels were significantly lower as compared to controls. Leptin levels decreased gradually with tumor stage and aggressiveness. Taken together, these results of this study suggest that adipokines, in particular resistin and leptin may be involved in development and progression of colon cancer.

Impact of smoking on the immunological profile of patients with laryngeal carcinoma

Immunity plays an important role in the prognosis and the natural development of cancer. Previous studies have shown that the presence of tumor in the body could modify the immune response leading to immunosuppression. The aim of this study was to evaluate the immunological changes of patients with larynx squamous cell carcinoma undergoing potentially curative surgery. We assessed the serum levels of cytokines (IL-1, IL-2, IL-4, IL-6, IL-8, IL-10, IFN-gamma, TNF-alpha, GM-CSF), chemokines (MCP-1 and MIP-1alpha) and growth factors (VEGF and bFGF) in laryngeal cancer patients before, during and after surgery. We have used a novel multianalyte XMap profiling technology that allows simultaneous measurement of multiple parameters in small volumes of samples. To investigate the changes in immune mediators' profile induced by tumor resection, we assessed the culture supernatants of the peripheral blood mononuclear cells (PBMC) derived from the patients, before and after surgery. The results suggested a predominance of a Th2 type of immune response associated with the presence of the tumor (especially in the case of heavy smokers who smoke more than 40 pack-years). However, shifts towards a Th1 type of immune response as well as an improvement of monocyte functions were noticed after surgery.

Primary cell culture of human adenocarcinomas--practical considerations

Cell culture is one of the major tools for oncology research, being an excellent system in which to study the biochemistry and molecular biology associated with individual cancer types and to understand cancer cell physiology. Progress in understanding the biology of any type of carcinoma has been impeded by the inability to culture adequately malignant cells from most epithelial tissues. The ultimate in vitro tumor model would completely reflect the in vivo tumor microenvironment in function and mechanism. Unfortunately, such a model does not currently exist. Homogeneous cell lines that can be continuously propagated on plastic surfaces have been extensively used as a surrogate for tumor environment; however they are very different from the in vivo tumor cells. Model systems involving primary culture represent the situation most closely related to the original tissue although they have a number of disadvantages over cell lines, such as the limited ability to repeat studies with a well characterized culture system that can be used in multiple laboratories. The primary culture may contain many types of stromal and infiltrating cell types potentially complicating the interpretation of data. Yet, their properties better reflect the cellular interactions present in intact tissue. The present article reviews the critical steps in obtaining, routine maintenance and cryopreservation of primary tumor cell cultures, based on information from literature and personal experience on the subject. The article also includes an updated protocol for primary tumor cell isolation and culture.

[Involvement of soluble mediators of inflammation in the pathogenic agent interaction--immune system in acute bacterial meningitis]

Acute Bacterial Meningitis is a medical emergency, which warrants early diagnosis and aggressive therapy, which in most cases must be initiated as an "empirical" treatment. Such an approach needs permanent epidemiological surveillance due to the major variability of the etiological agents depending upon time, geographical areas and demographic characteristics of the population. A program for the surveillance of meningitis is in progress in Romania, but the available clinical inbformation is incomplete and not well documented by paraclinical data, poorly reflecting the real incidence of the disease. The specific anatomic localization of the disease has major influences on the antiinfectious immune response. Inflammation is involved in the disease pathogenesis, especially in promotion and evolution of neurological sequelae (neuronal demyelinisation and degeneration) even in case of pathogen clearance following antimicrobial therapy. Activation of the immune response in a immunologically "privileged "region can lead to the break of tolerance and induction of autoimmunity (neuronal degenerescence). On the other hand, an efficient immune response is necessary for the clearance of pathogenic agents. A detailed investigation of the interaction between pathogenic agents and the immune system in relation to the particular meningeal localization and also a study on the involvement of soluble mediators of inflammation (cytokines, chemokines) in the pathogenesis of meningitis might prove useful for differential diagnosis (viral or "aseptic" meningitis) and also for elucidating the mechanisms which that underlie the disease pathogenesis/neurological complications.

Bacterial product cantastim derived from Pseudomonas aeruginosa induces migration and maturation of dendritic cells

Dendritic cells (DCs) play a pivotal role in linking innate and adaptive immunity. Migration to the lymph nodes and maturation of DCs are crucial steps in the initiation of specific immune responses. The bacterial product CANTASTIM (CS) is a purified extract of Pseudomonas aeruginosa that induces non-specific protection against bacterial infection, enhances macrophage effector functions and modulates cytokines production. In this study, we used a mouse skin explant culture model and human monocyte-derived DCs to study the effect of CS on the migration and maturation of DCs, respectively. We noticed a significant increase in the number of DCs which migrated from the skin explants when CS was added to the culture medium. Also, CS was able to induce the expression of maturation-associated marker CD83 on human monocyte-derived DCs. DC-based tumor vaccines represent a promising approach for cancer immunotherapy and the migration rate and maturation state of DCs are important parameters for their clinical effectiveness. CS may be an attractive candidate to be tested for the production of DC-based vaccine.

Cytokine profiling by multiplex immunoassay as an effective approach to assess immunomodulatory activity of bacterial product CANTASTIM

The bacterial product CANTASTIM (CS) is a purified extract of Pseudomonas aeruginosa that induces non-specific protection against bacterial infection, enhances macrophage effector functions and modulates production of cytokines. Most likely, it interacts with components of the innate immune response. Cytokine production can be used to assess the bioactivity of this product but these biomolecules operate in vivo in a complex regulatory network with reciprocal influences so there is a need for profiling an array of cytokines rather than an individual analysis. Current technology development of multiplex immunoassay for simultaneous measurement of multiple analytes in a single assay has greatly improved the throughput and cost effectiveness of cytokine profiling and proved to be an effective approach to evaluate the immunomodulatory activity of the bacterial product CS.

New insights into the pathogenesis and prognosis of aortic sclerosis

Aortic valve disease includes a wide spectrum of conditions, from leaflets thickening to hemodynamically significant aortic stenosis and is one of the most important causes of morbidity and mortality worldwide. Studies performed during the last years bring consistent evidence that these lesions of the aortic valves share remarkable similarities with atherosclerotic lesions. They also reveal new risk factors for its development, which are superposed in fact with the major risk factors for atherosclerosis. Moreover, large prospective studies reported an increased risk for cardiovascular events and for total and cardiovascular mortality in patients with aortic sclerosis. Hence, recent papers also propose therapeutic targets, using statins for delaying the progression of the disease.

Experimental studies on bacterial product cantastim derived from Pseudomonas aeruginosa. VI. Protection in tolerant mice

Endotoxin tolerance is defined as a hyporesponsiveness state to a second stimulation with lipopolysaccharide (LPS). This refractory state is primarily associated with an attenuated cytokine production. Whether this down-regulation of cytokine production results in an increased susceptibility to infection remains a matter of controversy. The aim of this study was to investigate the resistance of tolerant mice to a subsequent bacterial infection and the role of bacterial immunomodulator CANTASTIM (CS) in this experimental model. We have shown that the LPS-tolerant mice (intraperitoneally inoculated with LPS Salmonella typhimurium 10 microg/mouse, daily for two days) were protected against a challenge with Pseudomonas aeruginosa (LD 100) administered 24 h later. On the contrary, when the animals were challenged 1 h after the last LPS injection, they did not survive. However if these animals were pre-treated with CS 3 days before LPS treatment, they became resistant to a subsequent bacterial challenge. More interestingly, if the treatment with LPS was substituted with CS (same schedule, route of administration and doses) there was a significant increase in the survival of mice challenged with Pseudomonas aeruginosa after either 1 h or 24 h. In this case, the increase in the rate of survival was correlated with an enhanced production of IL-10 in the peritoneal cavities of CS treated mice as compared to LPS treated mice.

[A nonspecific immunostimulant effect with Cantastim on the cellular and humoral immune responses in mice evaluated by in vivo and in vitro tests]

The stimulatory effect was evaluated, of an ethanol extraction obtained from a pathogenic strain of Pseudomonas aeruginosa type XV. It was noted that this extract, commercially known as "Cantastim" has mitogenic effects in vitro for mouse lymphocytes, but not for those of humans or of guinea pigs. It activates the cytostatic functions of macrophages. It is thermoresistant, nonimmunogenic and it is not allergic. A low amount of proteins and carbohydrates are contained in this extract, but it contains over 80% phospholipids. It has a transient stimulating effect of the cytotoxic effects of NK cells, and it also activates the synthesis of antibodies from the IgM and the IgG classes. It probably stimulates the expression of receptors for PHA in the membrane of T lymphocytes, and retards the development of the Ehrlich ascites tumour, protecting at the same time the animals from severe infections with conditionally pathogenic germs. These data suggests that "Cantastim" is a potent immunomodulating agent that could be used successfully in the fight against certain chronic diseases with a bacterial or neoplastic etiology of humans.

Comparative study of the biological characteristics of mucoid and non-mucoid Pseudomonas aeruginosa strains isolated from chronic respiratory infections

Morphological, culture and enzymatic characteristics, as well as virulence, susceptibility to antimicrobial agents and epidemiological markers, were studied for 100 mucoid and 100 non-mucoid Ps. aeruginosa strains isolated from chronic respiratory infections. For 10 mucoid and 10 non-mucoid strains was performed the active protection test in mice, both with inactivated germs (10(9) germs), and LPS extracted by Westphal method. It was ascertained that mucoid Ps. aeruginosa strains differ from non-mucoid strains by the slow growth on culture media, more reduced proteolytic activity (81% as compared to 99%), slow oxidation of carbohydrates (5-7 days), reduced virulence in mice (8%) or avirulence (92%), higher sensitivity to some antibiotics (amikacin, dibekacin, ticarcillin, tetracycline, cefotaxime, ceftriaxone), lysoresistance (74%) and polyagglutinability (67%). The mucoid strains ensure a reduced active protection in mice, 70% of strains did not protect the mice against the infection with virulent homologous strains, while the non-mucoid strains ensured 80%-100% protection.