Combination of IL-8 plus TNF alpha induces additive neutrophil migration

Cross-kingdom microbial interactions in dental implant-related infections: is Candida albicans a new villain?

Candida albicans, an oral fungal opportunistic pathogen, has shown the ability to colonize implant surfaces and has been frequently isolated from biofilms associated with dental implant-related infections, possibly due to its synergistic interactions with certain oral bacteria. Moreover, evidence suggests that this cross-kingdom interaction on implant can encourage bacterial growth, leading to increased fungal virulence and mucosal damage. However, the role of Candida in implant-related infections has been overlooked and not widely explored or even considered by most microbiological analyses and therapeutic approaches. Thus, we summarized the scientific evidence regarding the ability of C. albicans to colonize implant surfaces, interact in implant-related polymicrobial biofilms, and its possible role in peri-implant infections as far as biologic plausibility. Next, a systematic review of preclinical and clinical studies was conducted to identify the relevance and the gap in the existing literature regarding the role of C. albicans in the pathogenesis of peri-implant infections.

Immune defence mechanisms and immunoenhancement strategies in oropharyngeal candidiasis

The prevalence of oropharyngeal candidiasis continues to be high, mainly because of an increasing population of immunocompromised patients. Traditional treatment of oropharyngeal candidiasis has relied on the use of antimicrobial drugs. However, unsatisfactory results with drug monotherapy and the emergence of resistant strains have prompted investigations into the potential use of adjunctive immunoenhancing therapies for the treatment of these infections. Here we review the host-recognition systems of Candida albicans, the immune and inflammatory response to infection, and antifungal effector mechanisms. The potential of immune modulation as a therapeutic strategy in oropharyngeal candidiasis is also discussed.

Tumor necrosis factor (TNF) is a potent rat mast cell chemoattractant

It is well known that mast cell number increases in local tissues under different pathophysiologic conditions, although the humoral factors that stimulate local mast cell accumulation within tissues are not yet well known. Taking into account that tumor necrosis factor (TNF) influences tissue mast cell activity in various ways, the aim of the present study was to investigate the chemotactic activity of TNF for rat peritoneal mast cells. We have found that TNF induces mast cell migratory response in a dose-dependent manner, even in the absence of extracellular matrix (ECM) proteins. Significant migration was observed at concentrations of TNF as low as approximately 3 fM; higher TNF concentrations caused significant inhibition of spontaneous mast cell migration. In the presence of ECM proteins, TNF induced migration of mast cells in a biphasic manner, with peaks of migration occurring at approximately 0.3 fM and approximately 60 pM (in the presence of fibronectin) and at approximately 0.6 fM and approximately 600 pM (in the presence of laminin). Under the same experimental conditions, RANTES induced dose-dependent mast cell migration, and the optimal concentration of this chemokine for maximal migration was approximately 13 nM. The mast cell migratory response to lower concentrations of TNF was chemotactic and to higher TNF concentrations was due to chemokinesis. TNF-induced mast cell migration was completely blocked by neutralizing anti-TNF and anti-TNFR1 antibodies. The tyrosine kinase inhibitor, genistein, significantly abrogated mast cell migration toward TNF. Additionally, we have documented that TNF does not induce degranulation of rat mast cells. Taken together, our results indicate that TNF serves as an extremely potent chemotactic factor for rat mast cells that would cause accumulation of these cells at the site of diverse pathophysiologic conditions accompanied by inflammation.

Invasive phenotype of Candida albicans affects the host proinflammatory response to infection

Candida albicans is a major opportunistic pathogen in immunocompromised patients. Production of proinflammatory cytokines by host cells in response to C. albicans plays a critical role in the activation of immune cells and final clearance of the organism. Invasion of host cells and tissues is considered one of the virulence attributes of this organism. The purpose of this study was to investigate whether the ability of C. albicans to invade host cells and tissues affects the proinflammatory cytokine responses by epithelial and endothelial cells. In this study we used the invasion-deficient RIM101 gene knockout strain DAY25, the highly invasive strain SC5314, and highly invasive RIM101-complemented strain DAY44 to compare the proinflammatory cytokine responses by oral epithelial or endothelial cells. Using a high-throughput approach, we found both qualitative and quantitative differences in the overall inflammatory responses to C. albicans strains with different invasive potentials. Overall, the highly invasive strains triggered higher levels of proinflammatory cytokines in host cells than the invasion-deficient mutant triggered. Significant differences compared to the attenuated mutant were noted in interleukin-1alpha (IL-1alpha), IL-6, IL-8, and tumor necrosis factor alpha in epithelial cells and in IL-6, growth-related oncogene, IL-8, monocyte chemoattractant protein 1 (MCP-1), MCP-2, and granulocyte colony-stimulating factor in endothelial cells. Our results indicate that invasion of host cells and tissues by C. albicans enhances the host proinflammatory response to infection.

Red blood cells stimulate human lung fibroblasts to secrete interleukin-8

Following lung injury, red blood cells (RBC) may interact with extracellular matrix (ECM). Fibroblasts, the resident cell in the ECM, have the capacity to produce and secrete a variety of mediators including interleukin-8 (IL-8). In the present study we hypothesized that RBC, or soluble factors released from them, may stimulate IL-8 production by fibroblasts. Fibroblasts were cultured in a three-dimensional collagen gel culture system in the presence or absence of RBC or conditioned medium from RBC (RBC-CM). IL-8 release from fibroblasts was significantly increased when cultured with RBC or RBC-CM and both tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) further stimulated this IL-8 secretion. The enhanced production of IL-8 within fibroblasts was accompanied by increased IL-8 mRNA expression. To evaluate whether RBC-fibroblast interaction may lead to recruitment of neutrophils, a functional migration assay was performed. RBC and RBC-CM, in the presence of IL-1beta and TNF-alpha, increased the transmigration of neutrophils. Our results indicate that RBC, when interacting with ECM, may participate in the recruitment of inflammatory cells by stimulating fibroblasts to secrete IL-8. This might be an important mechanism regulating tissue repair after injury.

Neutrophil chemotactic activity of sputum from patients with COPD: role of interleukin 8 and leukotriene B4

STUDY OBJECTIVES

Neutrophilic inflammation is a major feature of COPD. Several factors in bronchial secretions have been identified as chemoattractants for neutrophils. The present study was designed to assess the contribution of interleukin (IL)-8 and leukotriene B(4) (LTB(4)) to neutrophil chemotaxis evoked by sputum obtained from patients with established COPD.

DESIGN

Sputum supernatant of 20 patients with COPD was used as chemoattractant in a 96-well chemotaxis chamber, with subsequent quantification of migrated cells by a luminescence assay. The contribution of IL-8 and LTB(4) to chemotaxis was determined by addition of a neutralizing antibody and a selective receptor antagonist, respectively.

MEASUREMENTS AND RESULTS

COPD sputum caused neutrophil chemotaxis in a concentration-dependent manner, with a maximum response evoked with a 10-fold dilution of the original sample. Pretreatment of sputum or neutrophils with either an anti-IL-8 antibody or the LTB(4) antagonist, SB 201146, led to a concentration-dependent inhibition of sputum-induced neutrophil chemotaxis, with a maximum suppression (mean +/- SEM) of 29.2 +/- 4.9% (p < 0.001) from baseline by 100 ng/mL of anti-IL-8 antibody, and 45.6 +/- 7% (p < 0.02) by 10 micro mol/L of SB 201146. The combination of the anti-IL-8 antibody and SB 201146 inhibited neutrophil chemotaxis, but this was not significantly greater than the effect of SB 201146 or anti-IL-8 alone.

CONCLUSIONS

These data confirm the importance of IL-8 and LTB(4) as chemoattractants for neutrophils in bronchial secretions from patients with COPD, and suggest that specific inhibitors may have therapeutic potential in COPD.

Sputum levels of metalloproteinase-9 and tissue inhibitor of metalloproteinase-1, and their ratio correlate with airway obstruction in lung transplant recipients: relation to tumor necrosis factor-alpha and interleukin-10

BACKGROUND

Chronic transplant rejection is characterized by progressive narrowing of small airways caused by matrix remodeling and fibrosis. Matrix-metalloproteinases (MMPs) and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), are involved in the turnover of extracellular matrix.

METHODS

To clarify the contribution of MMPs and TIMPs to airway inflammation in patients after lung transplantation (LTx), we used enzyme immunoassays to measure induced sputum concentrations of MMP-9, TIMP-1, and controlling cytokines tumor necrosis factor (TNF)-alpha and interleukin (IL)-10 of 30 LTx patients and 15 control subjects.

RESULTS

Sputum concentrations of MMP-9, TIMP-1, the MMP-9:TIMP-1 ratio, and TNF-alpha were higher in LTx patients than in control subjects (p < 0.04, all comparisons). The MMP-9, MMP-9:TIMP-1, and TNF-alpha levels were also significantly higher in LTx patients with chronic rejection compared with those with stable organ function (p < 0.03, all comparisons), whereas IL-10 levels were higher in the latter group (p = 0.05). In all LTx patients, MMP-9 and the MMP-9:TIMP-1 ratio were negatively correlated with forced expiratory volume in 1 second values (rho = -0.47, p = 0.01, and rho = -0.53, p = 0.003, respectively). We found that MMP-9 positively correlated with sputum neutrophils and TNF-alpha whereas MMP-9 and TIMP-1 did not correlate with IL-10.

CONCLUSIONS

These data underline the possible contribution of proteases such as MMP-9 to chronic transplant rejection, and suggest that an imbalance of MMP-9 and TIMP-1 may be involved in the pathogenesis of airway obstruction after LTx. We found that MMP-mediated inflammation seems to be controlled by TNF-alpha whereas IL-10 might elicit anti-inflammatory effects through different pathways.

In vitro biocompatibility study of electrically conductive polypyrrole-coated polyester fabrics

This study investigated the basic biocompatibility aspects of two types of polypyrrole (PPy)-coated polyester fabrics for possible use as vascular prostheses. These PPy-coated fabrics, PPy-Phos and PPy-Plas, were sterilized with ethylene oxide (EO) and the following characterizations were performed: surface morphology by scanning electron microscope, EO residuals analysis by the headspace method, acute systemic toxicity in the mouse model, hemolysis, blood coagulation time, viability and proliferation of endothelial cells measured with the WST-1 method, and activation of polymorphonuclear (PMN) cells indicated by the specific expression of interleukin 8 mRNA measured by reverse transcription polymerase chain reaction. Virgin polyester fabrics, expanded poly(tetrafluoroethylene) (ePTFE), and medical-grade Bionate 80A poly(carbonate urethane) were used as references in the cell culture experiments. The PPy-coated fabrics revealed different surface morphologies by showing more PPy lamina and clusters on the PPy-Plas. Neither of the PPy-coated fabrics had an adverse effect on hemolysis and coagulation time, and they did not cause any acute systemic toxicity. The EO residual level was as low as 5 ppm or less, which is considered quite acceptable. Although exhibiting a relatively low initial cell adhesion at 24 h, the two PPy-coated samples showed no cytotoxicity at 72 and 168 h. Bionate 80A and ePTFE recorded cytotoxicity at 72 and 168 h, respectively. The virgin fabrics also demonstrated a decrease of viable cells at 72 h that was not significant. The activation of PMN cells induced by both PPy-coated fabrics, the ePTFE, and the negative control was significantly lower than that induced by their respective tumor necrosis factor-alpha controls. These results therefore highlighted the potential of PPy-coated fabrics for use as cardiovascular prostheses. It was suggested that cell adhesion moieties should be incorporated into the PPy/fabric composite to increase cell adhesion and subsequent cell proliferation.