Interleukin (IL)-4 induces production of cytokine-induced neutrophil chemoattractants (CINCs) and intercellular adhesion molecule (ICAM)-1 in lungs of asthmatic rats

Impact of Digestive Inflammatory Environment and Genipin Crosslinking on Immunomodulatory Capacity of Injectable Musculoskeletal Tissue Scaffold

The paracrine and autocrine processes of the host response play an integral role in the success of scaffold-based tissue regeneration. Recently, the immunomodulatory scaffolds have received huge attention for modulating inflammation around the host tissue through releasing anti-inflammatory cytokine. However, controlling the inflammation and providing a sustained release of anti-inflammatory cytokine from the scaffold in the digestive inflammatory environment are predicated upon a comprehensive understanding of three fundamental questions. (1) How does the release rate of cytokine from the scaffold change in the digestive inflammatory environment? (2) Can we prevent the premature scaffold degradation and burst release of the loaded cytokine in the digestive inflammatory environment? (3) How does the scaffold degradation prevention technique affect the immunomodulatory capacity of the scaffold? This study investigated the impacts of the digestive inflammatory environment on scaffold degradation and how pre-mature degradation can be prevented using genipin crosslinking and how genipin crosslinking affects the interleukin-4 (IL-4) release from the scaffold and differentiation of naïve macrophages (M0). Our results demonstrated that the digestive inflammatory environment (DIE) attenuates protein retention within the scaffold. Over 14 days, the encapsulated protein released 46% more in DIE than in phosphate buffer saline (PBS), which was improved through genipin crosslinking. We have identified the 0.5 (w/v) genipin concentration as an optimal concentration for improved IL-4 released from the scaffold, cell viability, mechanical strength, and scaffold porosity, and immunomodulation studies. The IL-4 released from the injectable scaffold could differentiate naïve macrophages to an anti-inflammatory (M2) lineage; however, upon genipin crosslinking, the immunomodulatory capacity of the scaffold diminished significantly, and pro-inflammatory markers were expressed dominantly.

Use of a biopolymer delivery system to investigate the influence of interleukin-4 on recruitment of neutrophils in equids

OBJECTIVE

To use a biopolymer delivery system to investigate the ability of interleukin (IL)-4 to recruit neutrophils into subcutaneous tissues of equids.

ANIMALS

16 horses and 2 ponies.

PROCEDURES

Animals were assigned to 3 experiments (6/experiment). Effects of recombinant equine (Req) IL-4 (100, 250, or 500 ng/site) versus a positive control (ReqIL-8; 100 ng, 250 ng, or 1 μg/site) and a negative control (Dulbecco PBSS or culture medium) on neutrophil chemotaxis were assessed after SC injection into the neck with an injectable biopolymer used as the vehicle. Tissue samples including the biopolymer plug were collected by biopsy at various time points from 3 hours to 7 days after injection. Neutrophil infiltration was evaluated by histologic scoring (experiments 1, 2, and 3) or flow cytometry (experiment 3).

RESULTS

Histologic neutrophil infiltration scores did not differ significantly among treatments at most evaluated time points. On flow cytometric analysis, log-transformed neutrophil counts in biopsy specimens were significantly greater for the ReqIL-8 treatment (1 μg/site) than the negative control treatment at 3 but not 6 hours after injection; results did not differ between ReqIL-4 and control treatments at either time point. Negative control treatments induced an inflammatory response in most equids in all experiments.

CONCLUSIONS AND CLINICAL RELEVANCE

Flow cytometry was a more reliable method to estimate neutrophil migration than histologic score analysis. The ReqIL-4 treatment did not induce a detectable neutrophil response, compared with the negative control treatment in this study. Evidence of inflammation in negative control samples suggested the biopolymer is not a suitable vehicle for use in equids.

Modulation of the IL-23/IL-17 axis by fenofibrate ameliorates the ovalbumin/lipopolysaccharide-induced airway inflammation and bronchial asthma in rats

The overlapping between asthmatic subtypes, including both CD4+ T helper (TH)2 and TH17 cells, is found in the natural course of allergic asthma, especially in exacerbations and severe and insensitive forms to steroids, which are in need of new molecular therapies. In the TH2-subset mediated asthma, fenofibrate displays therapeutic promises, besides evidenced therapeutic effects on TH17-mediated colitis and myocarditis. Therefore, the effects of fenofibrate versus dexamethasone on IL-23/IL-17 axis in ovalbumin (OVA)/lipopolysaccharide (LPS)-induced airway inflammation and bronchial asthma in rats were explored. The OVA/LPS sensitization and challenge were performed for 28 days in male Wistar rats. After sensitization, fenofibrate (100 mg/kg/day) or dexamethasone (2.5 mg/kg/day) was orally administered from the day 15 to 28. Either fenofibrate or dexamethasone attenuated the severity of OVA/LPS-induced airway inflammation and bronchial asthma through significant ameliorations in the total serum immunoglobulin (Ig)E assay; the total and differential leukocytic counts in the bronchoalveolar lavage (BAL) fluid; the lung inflammatory cytokines such as interleukin (IL)-4, IL-13, IL-17, and IL-23, transforming growth factor (TGF)-β₁, and tumor necrosis factor(TNF)-α levels; and the lung IL-17 and IL-23 expressions. In addition to the reduction in the inflammatory and fibrotic histopathological scores, fenofibrate significantly ameliorated the BAL neutrophilic count and the lung IL-17 and IL-23 expressions in comparison to dexamethasone. The suppression of IL-23/IL-17 axis could be considered a molecular therapeutic target for fenofibrate in OVA/LPS-induced airway inflammation and bronchial asthma. Combined therapeutic regimens of fenofibrate and steroids should be furtherly investigated in severe and resistant asthma.

In vivo lung perfusion rehabilitates sepsis-induced lung injury

BACKGROUND

Sepsis is the leading cause of lung injury in adults and can lead to acute respiratory distress syndrome (ARDS). Using a novel technique of isolated in vivo lung perfusion (IVLP), we hypothesized that normothermic IVLP will improve oxygenation and compliance in a porcine model of sepsis-induced lung injury.

METHODS

Mature adult swine (n = 8) were administered lipopolysaccharide (LPS; 50 μg/kg over 2 hours) via the external jugular vein, followed by sternotomy and central extracorporeal membrane oxygenation (ECMO) cannulation (right atrium to ascending aorta). The left pulmonary artery (inflow) and left superior and inferior pulmonary veins (outflow) were dissected out and cannulated to deliver isolated perfusion to the left lung. After 4 hours of normothermic IVLP with Steen solution, the left lung then underwent 4 hours of reperfusion after IVLP decannulation. Airway pressures and lung-specific pulmonary vein blood gases from the right lung (LPS control) and left lung (LPS + IVLP) of the same animal were compared.

RESULTS

All animals demonstrated a significant reduction in the ratio of partial pressure of oxygen in arterial blood (PaO₂)/fraction of inspired oxygen (FiO₂) (P/F ratio) and total lung compliance at 2 hours after the start of LPS infusion (mean, 469 ± 19.7 mm Hg vs 222.2 ± 21.4 mm Hg; P < .0001). After reperfusion, 6 animals (75%) exhibited improved lung function, allowing for ECMO decannulation. Lung-specific oxygenation was superior in the left lung after 4 hours of reperfusion (mean, 310.5 ± 54.7 mm Hg vs 201.1 ± 21.7 mm Hg; P = .01). Similarly, total lung compliance improved after IVLP of the left lung. The lung wet weight to dry weight ratio demonstrated reduced edema in rehabilitated left lungs (mean, 6.5 ± 0.3 vs 7.5 ± 0.4; P = .04).

CONCLUSIONS

IVLP successfully rehabilitated LPS-injured lungs compared to ECMO support alone in this preclinical porcine model.

Regulatory effect of cytokine-induced neutrophil chemoattractant, epithelial neutrophil-activating peptide 78 and pyrrolidine dithiocarbamate on pulmonary neutrophil aggregation mediated by nuclear factor-κB in lipopolysaccharide-induced acute respiratory distress syndrome mice

In the present study, the regulatory effect of cytokine-induced neutrophil chemoattractant (CINC) and epithelial neutrophil-activating peptide 78 (ENA-78) on pulmonary neutrophil (PMN) accumulation in lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) mice, and the therapeutic effect of pyrrolidine dithiocarbamate (PDTC), was investigated. BALB/c mice were divided into control, LPS and PDTC + LPS groups using a random number table. The phosphorylation of nuclear factor-κB (NF-κB) was detected using a western blot, and the mRNA expression levels of CINC were evaluated using reverse transcription-quantitative polymerase chain reaction. The expression of NF-κB, CINC and ENA-78 was detected using immunohistochemistry. The production of interleukin (IL)-8 and IL-10 in serum and broncho-alveolar lavage fluid (BALF) was analyzed using an enzyme-linked immunosorbent assay. The total number of leukocytes and proportion of PMNs in BALF was also determined. Following injection with LPS (20 mg/kg), the expression levels of p-NF-κB, CINC and ENA-78 were increased in lung tissue, and the expression levels of IL-8, IL-10 and the number of PMNs increased in serum and BALF. However, in comparison with the LPS group, the degree of lung injury was reduced in ARDS mice that were treated with PDTC. In addition, the expression level of p-NF-κB and the production of chemokines in lung tissue decreased in ARDS mice that were treated with PDTC, and the number of PMNs in BALF also decreased. In conclusion, the results of the present study suggest that the LPS-induced phosphorylation of NF-κB may result in the synthesis and release of CINC and ENA-78, which induce the accumulation of PMNs in the lung. Therefore, PDTC may be used to reduce the production of chemokines and cytokines, thereby decreasing the activation of PMNs in lung tissue and reducing the damage of lung tissue in ARDS.

Novel mechanisms of sildenafil in pulmonary hypertension involving cytokines/chemokines, MAP kinases and Akt

Pulmonary arterial hypertension (PH) is associated with high mortality due to right ventricular failure and hypoxia, therefore to understand the mechanism by which pulmonary vascular remodeling initiates these processes is very important. We used a well-characterized monocrotaline (MCT)-induced rat PH model, and analyzed lung morphology, expression of cytokines, mitogen-activated protein kinase (MAPK) phosphorylation, and phosphatidylinositol 3-kinase-Akt (PI-3k-Akt) pathway and nuclear factor (NF)-κB activation in order to elucidate the mechanisms by which sildenafil's protective effect in PH is exerted. Besides its protective effect on lung morphology, sildenafil suppressed multiple cytokines involved in neutrophil and mononuclear cells recruitment including cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2α/β, tissue inhibitor of metalloproteinase (TIMP)-1, interleukin (IL)-1α, lipopolysaccharide induced CXC chemokine (LIX), monokine induced by gamma interferon (MIG), macrophage inflammatory protein (MIP)-1α, and MIP-3α. NF-κB activation and phosphorylation were also attenuated by sildenafil. Furthermore, sildenafil reduced extracellular signal-regulated kinase (ERK)1/2 and p38 MAPK activation while enhanced activation of the cytoprotective Akt pathway in PH. These data suggest a beneficial effect of sildenafil on inflammatory and kinase signaling mechanisms that substantially contribute to its protective effects, and may have potential implications in designing future therapeutic strategies in the treatment of pulmonary hypertension.