Porcine Trachea Research Articles

Comparative quasi-static mechanical characterization of fresh and stored porcine trachea specimens

Tissues of the upper airways of critically ill patients are particularly vulnerable to mechanical damage associated with the use of ventilators. Ventilation is known to disrupt the structural integrity of respiratory tissues and their function. This damage contributes to the vulnerability of these tissues to infection. We are currently developing tissue models of damage and infection to the upper airways. As part of our studies, we have compared how tissue storage conditions affect mechanical properties of excised respiratory tissues using a quasi-static platform. Data presented here show considerable differences in mechanical responses of stored specimens compared to freshly excised specimens. These data indicate that implementation of storage and maintenance procedures that minimize rapid degradation of tissue structure are essential for retaining the material properties in our tissue trauma models.

Dynamic Assessment of Ca2+ Sensitivity of Isometric Force in Intact Airway Smooth Muscle Using Phase Loop Plots

A transient elevation of cytosolic Ca2+ concentration ([Ca2+]cyt) triggers a force response in excitation‐contraction coupling. The Ca2+ sensitivity of muscle reflects the relationship between [Ca2+]cyt and force, and in skeletal and cardiac muscle is often defined as the [Ca2+]cyt at which 50% force is generated (ED50). In smooth muscle, Ca2+ sensitivity has been assessed as the ratio of peak force to peak cytosolic [Ca2+]cyt. However, this conventional measurement overlooks the dynamic nature of Ca2+ regulation of force generation. In the present study, in order to provide a dynamic index of Ca2+ sensitivity in airway smooth muscle (ASM), we simultaneously measured [Ca2+]cyt and force and determined their temporal dependence using a phase loop plot. We examined the phase loop plot assessment of Ca2+ sensitivity in ASM under the condition in which the conditional assessment indicated an increase (Calyculin A treatment) in Ca2+ sensitivity. Intact ASM strips were isolated from porcine tracheas obtained from local abattoir. ASM strips were loaded with Fura‐2 AM (Ca2+ fluorescent indicator) and stimulated using 1 mM ACh. Isometric force and [Ca2+]cyt responses were simultaneously measured using a Guth Muscle Research System. ASM strips were exposed to Calyculin A (phosphatase inhibitor; 100 nM for 10 min), which was previously reported to alter static Ca2+ sensitivity. Phase loop plots were calculated from simultaneous [Ca2+]cyt and force responses. The extent of rMLC phosphorylation was determined at different time periods after ACh stimulation using Phos‐tag SDS‐PAGE (SuperSep Phos‐tag; Wako Pure Chemical Industries, Ltd.) and Western blotting. Calyculin A increased ACh‐induced isometric force in ASM strips, but it had no effect on the amplitude of evoked [Ca2+]cyt transients. These results suggested that Calyculin A increased static Ca2+ sensitivity. However, the phase loop plots showed no significant shift in dynamic Ca2+ sensitivity with Calyculin A. These results indicate that the phase loop plot provides a valuable tool to assess dynamic Ca2+ sensitivity of isometric force generation in ASM, which better reflects the complex process of excitation‐contraction coupling in smooth muscle. These results further indicate that dynamic Ca2+ sensitivity of force generation in ASM is independent of rMLC phosphorylation.Support or Funding InformationSupported by NIH grant HL126451 (GCS)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Imidazole-induced contractions in bovine tracheal smooth muscle are not dependent on the cAMP pathway.

The mechanism of imidazole-induced contraction on the bovine tracheal smooth muscle was investigated. Imidazole induced muscle contraction in a concentration-dependent manner on bovine, porcine and guinea-pig tracheas, but not in rat or mouse. In bovine tracheas, imidazole was cumulatively applied and induced muscle tension and increasesd intracellular Ca2+ level in a concentration -dependent manner. Imidazole, even at 300 µM, the concentration at which maximum contractile response occurs, did not significantly increase in cAMP content relative to control. Atropine inhibited imidazole-induced contraction at a concentration- dependent manner and pretreatment of hemicholinium-3 almost abolished imidazole-induced contraction. Conversely, pretreatment of tripelennamine, indomethacin or tetrodotoxin did not affect imidazole-induced contraction. Acetylcholine or eserine induced contraction in bovine, porcine, guinea pig, rat and mice trachea in a concentration-dependent manner. However, there was little difference in the rank order of maximum contraction of these agents. Imidazole-induced contraction was greater in bovine trachea compared to the other species tested. Further, cAMP did not appear to play a role in imidazole-induced contraction, suggesting other mechanisms, such as the release of endogenous acetylcholine.

Characteristic oligosaccharides released from acid hydrolysis for the structural analysis of chondroitin sulfate

Because the glycosidic linkage of uronic acid is most resistant to acid, oligosaccharides may be formed during the acid hydrolysis of acidic polysaccharides. To take chondroitin sulfate (CS) as an example of acidic polysaccharides, the present study characterized the oligosaccharides released through acid hydrolysis and demonstrated their usefulness for structural confirmation. Acid hydrolysates of commercial standard CSs from shark cartilage and porcine bone were elucidated using HPLC-MSn after 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization, and altogether 11 di-, tri- and tetra-saccharides with or without sulfate/acetyl groups were identified by their multi-stage mass spectra. Meanwhile the trends of reaction yields of these oligosaccharides alone with trifluoroacetic acid (TFA) concentrations (0.1–2.0 M) were investigated, and 0.2 M TFA was recommended. Then three real samples, sturgeon backbone, porcine trachea and sea cucumber were analyzed, and their CSs were identified by detection of characteristic oligosaccharide fragments. The present study indicated that acid hydrolysis could provide information for acetyl substitution, sulfation and glycosidic linkages, and was helpful for the structural analysis of acidic polysaccharides.

Do chondroitin sulfates with different structures have different activities on chondrocytes and macrophages?

The aim of the present study was to investigate the activities of natural chondroitin sulfates (CS) with different structures on cultured chondrocytes and macrophages. CS were isolated from cartilages of bovine trachea (BT), porcine trachea (PT), chicken sternum (Ch) and skate (Sk). The preparations were 90–98% pure, with ∼1% proteins, nucleic acids and keratan sulfate contaminants. Structural analysis of these CS and of commercial chondroitin 4- and 6-sulfate (C4S, C6S) have shown that most of their disaccharides are monosulfated, with varying proportions of 4- and 6-sulfation, and 2–7% non-sulfated disaccharides. Sk-CS and C6S contained detectable amounts of disulfated disaccharides. All the CS were polydisperse, with modal molecular weights of 26–135kDa. These CS had anti-inflammatory activities on both chondrocytes and macrophages, but with different efficiencies. On horse and human chondrocytes, they reduced the IL-1β-induced liberation of NO and PGE2, and on RAW 264.7 immortalized macrophage-like cell line, C4S, C6S, Ch and Sk-CS decreased the LPS-induced liberation of TNF-α, but did not affect IL-6. In contrast, on bone marrow derived macrophages, C4S, C6S, BT and PT-CS reduced the LPS-induced liberation of TNF-α, IL-6, IL-1β and NO, indicating that the RAW response to CS was different from that of primary macrophages.

Use of Phase Loop Plots to Assess Ca2+ Sensitivity of Force Generation in Airway Smooth Muscle

In excitation‐contraction coupling, a transient elevation of cytosolic Ca2+ concentration ([Ca2+]cyt) triggers a force response. The Ca2+ sensitivity of muscle reflects the relationship between [Ca2+]cyt and force, and in skeletal and cardiac muscle is often defined as the [Ca2+]cyt at which 50% force is generated. In smooth muscle, Ca2+ sensitivity has been assessed as the ratio of peak force to peak cytosolic [Ca2+]cyt. However, this measurement overlooks the dynamic nature of Ca2+ regulation of force generation. In the present study, in order to provide a dynamic index of Ca2+ sensitivity in airway smooth muscle (ASM), we simultaneously measured [Ca2+]cyt and force and determined their temporal dependence using a phase loop plot. We hypothesized that [Ca2+]cyt/force phase loop plot in ASM would be altered by conditions in which the extent of regulatory myosin light chain (rMLC) phosphorylation was affected.Intact ASM strips were isolated from porcine tracheas obtained from local abattoir. ASM strips, were loaded with Fura‐2 AM (Ca2+ fluorescent indicator) and stimulated using 1 μM ACh. Isometric force and [Ca2+]cyt responses were simultaneously measured using a Guth Muscle Research System. In the first set of experiments we examined the effect of Y27623, a Rho‐kinase inhibitor, and calyculin A, a protein phosphatase inhibitor that affected Ca2+‐induced rMLC phosphorylation. In a second set of experiments, we examined the effect of cytochalasin D (Cyto‐D), an inhibitor of actin polymerization, which reduces force independent of Ca2+‐induced rMLC phosphorylation.As expected, Y27623 decreased ACh‐induced isometric force but had no effect on evoked [Ca2+]cyt transients. Cyto‐D also decreased force with no effects on evoked [Ca2+]cyt. By comparison, calyculin A increased force with no effect on [Ca2+]cyt. Although these results suggest changes in Ca2+ sensitivity, the phase loop plots showed no significant shift indicative of changes in dynamic Ca2+ sensitivity. These results do not support our hypothesis that dynamic Ca2+ sensitivity in ASM is modulated by the extent of rMLC phosphorylation. Under these experimental conditions, it appears that isometric force generation in ASM is not entirely dependent on [Ca2+]cyt.Support or Funding InformationSupported by NIH grant HL126451 (GCS)

Airway compliance measured by anatomic optical coherence tomography.

Quantification of airway compliance can aid in the diagnosis and treatment of obstructive airway disorders by detecting regions vulnerable to collapse. Here we evaluate the ability of a swept-source anatomic optical coherence tomography (SSaOCT) system to quantify airway cross-sectional compliance (CC) by measuring changes in the luminal cross-sectional area (CSA) under physiologically relevant pressures of 10-40 cmH2O. The accuracy and precision of CC measurements are determined using simulations of non-uniform rotation distortion (NURD) endemic to endoscopic scanning, and experiments performed in a simplified tube phantom and ex vivo porcine tracheas. NURD simulations show that CC measurements are typically more accurate than that of the CSAs from which they are derived. Phantom measurements of CSA versus pressure exhibit high linearity (R2>0.99), validating the dynamic range of the SSaOCT system. Tracheas also exhibited high linearity (R2 = 0.98) suggestive of linear elasticity, while CC measurements were obtained with typically ± 12% standard error.

Multi-modal anatomical Optical Coherence Tomography and CT for in vivo Dynamic Upper Airway Imaging.

We describe a novel, multi-modal imaging protocol for validating quantitative dynamic airway imaging performed using anatomical Optical Coherence Tomography (aOCT). The aOCT system consists of a catheter-based aOCT probe that is deployed via a bronchoscope, while a programmable ventilator is used to control airway pressure. This setup is employed on the bed of a Siemens Biograph CT system capable of performing respiratory-gated acquisitions. In this arrangement the position of the aOCT catheter may be visualized with CT to aid in co-registration. Utilizing this setup we investigate multiple respiratory pressure parameters with aOCT, and respiratory-gated CT, on both ex vivo porcine trachea and live, anesthetized pigs. This acquisition protocol has enabled real-time measurement of airway deformation with simultaneous measurement of pressure under physiologically relevant static and dynamic conditions- inspiratory peak or peak positive airway pressures of 10-40 cm H2O, and 20-30 breaths per minute for dynamic studies. We subsequently compare the airway cross sectional areas (CSA) obtained from aOCT and CT, including the change in CSA at different stages of the breathing cycle for dynamic studies, and the CSA at different peak positive airway pressures for static studies. This approach has allowed us to improve our acquisition methodology and to validate aOCT measurements of the dynamic airway for the first time. We believe that this protocol will prove invaluable for aOCT system development and greatly facilitate translation of OCT systems for airway imaging into the clinical setting.

Swept-Source Anatomic Optical Coherence Elastography of Porcine Trachea.

Quantitative endoscopic imaging is at the vanguard of novel techniques in the assessment upper airway obstruction. Anatomic optical coherence tomography (aOCT) has the potential to provide the geometry of the airway lumen with high-resolution and in 4 dimensions. By coupling aOCT with measurements of pressure, optical coherence elastography (OCE) can be performed to characterize airway wall stiffness. This can aid in identifying regions of dynamic collapse as well as informing computational fluid dynamics modeling to aid in surgical decision-making. Toward this end, here we report on an anatomic optical coherence tomography (aOCT) system powered by a wavelength-swept laser source. The system employs a fiber-optic catheter with outer diameter of 0.82 mm deployed via the bore of a commercial, flexible bronchoscope. Helical scans are performed to measure the airway geometry and to quantify the cross-sectional-area (CSA) of the airway. We report on a preliminary validation of aOCT for elastography, in which aOCT-derived CSA was obtained as a function of pressure to estimate airway wall compliance. Experiments performed on a Latex rubber tube resulted in a compliance measurement of 0.68±0.02 mm2/cmH2O, with R2=0.98 over the pressure range from 10 to 40 cmH2O. Next, ex vivo porcine trachea was studied, resulting in a measured compliance from 1.06±0.12 to 3.34±0.44 mm2/cmH2O, (R2>0.81). The linearity of the data confirms the elastic nature of the airway. The compliance values are within the same order-of-magnitude as previous measurements of human upper airways, suggesting that this system is capable of assessing airway wall compliance in future human studies.

Differentiation of respiratory epithelium in a 3-dimensional co-culture with fibroblasts embedded in fibrin gel

Background: Tracheal tissue engineering is a promising option for the treatment of tracheal defects. In a previous study we proved the suitability of fibrin gel as a scaffold for tracheal tissue engineering. This study investigates whether the differentiation of respiratory epithelium can be increased by culturing epithelial cells in a three dimensional system containing fibroblasts embedded into fibrin gel. Methods: Respiratory epithelial cells were isolated from porcine trachea, seeded onto a fibrin gel and kept in air-liquid-interface culture for 33 days. Morphology as well as pan-cytokeratin, MUC5AC and claudin-1 expression of cells cultured on pure fibrin gel were compared to culture on gels containing fibroblasts. Results: After two weeks, cells seeded on pure fibrin gel were multilayered, showed hyperproliferation and dedifferentiation. Co-cultured cells built up a pseudostratified epithelium. The differentiation and organization of epithelial structure improved with respect to time. After four weeks, morphology of the co-cultured respiratory epithelium resembled native tracheal epithelium. Immunohistochemistry showed that respiratory epithelium co-cultured with fibroblasts had an increasing similarity of pan-cytokeratin expression compared to native trachea. Cells cultured without fibroblasts differed in pan-cytokeratin expression from native trachea and did not show any improvement of differentiation. Immunohistochemical staining of MUC5AC and claudin-1 proved seeded cells being respiratory epithelial cells. Conclusions: This study indicates that adding fibroblasts to fibrin gel positively influences the differentiation of respiratory epithelium.

Biomechanical and biochemical characterization of porcine tracheal cartilage.

The trachea is essential to respiratory function and is a mechanically and biochemically complex composite tissue. Tissue-engineering approaches to treat tracheal diseases require detailed knowledge of the native mechanical and biochemical properties of the trachea. Although the porcine trachea represents an excellent preclinical model, relevant mechanical and biochemical composition are incompletely characterized. Experimental. The mechanical and biochemical properties of 12 intact porcine tracheas were determined to characterize their compliance, as well as the aggregate modulus, bidirectional elastic modulus, hydraulic permeability, and biochemical characteristics of individual cartilage rings. Data demonstrate the glycosaminoglycan content of tracheal rings was (mean ± standard deviation) 190 ± 49 μg/mg. Hydroxyproline content was 8.2 ± 3.2 μg/mg, and DNA content was 1.3 ± 0.27 μg/mg, a four-fold difference between circumferential elastic modulus (5.6 ± 2.0 megapascal [MPa]) and longitudinal composite elastic modulus (1.1 ± 0.7 MPa, P < 0.0001) was also observed. Aggregate modulus (stiffness) of porcine tracheal rings was 1.30 ± 0.28 MPa, and inflationary compliance was 0.00472 ± 0.00188 cmH2 O(-1) . This study presents a comprehensive characterization of the relevant biochemical and mechanical properties of porcine tracheal cartilage, which is considered an excellent candidate for xenogenic tracheal graft and a source for tissue-engineered tracheal reconstruction. The range of parameters characterized in this study agrees with those reported for hyaline cartilage of the airway in other species. These characteristics can be used as quantitative benchmarks for tissue-engineering approaches to treat tracheal disease. NA. Laryngoscope, 126:E325-E331, 2016.

Isolation and characterization of pepsin solubilized type II collagen from porcine cartilage and cartilagious fish for intervertebral disc (IVD) regeneration

Event Abstract Back to Event Isolation and characterization of pepsin solubilized type II collagen from porcine cartilage and cartilagious fish for intervertebral disc (IVD) regeneration Zhuning Wu1, 2*, Anne Maria Mullen3, Abhay Pandit2 and Dimitrios Zeugolis1, 2 1 National University of Ireland Galway (NUI Galway), Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Ireland 2 National University of Ireland Galway (NUI Galway), Centre for Research in Medical Devices (CÚRAM), Ireland 3 Food Research Centre, Teagasc, Ireland Introduction: Collagen is the main component of ECM with 29 types identified. Type II collagen presents supportive function in cartilaginous tissues. Since type II collagen is the major component of nucleus pulposus in intervertebral disc, the potential of injectable type II collagen hydrogel as a cell carrier for intervertebral disc regeneration is being investigated in this project. At this stage, we isolated and characterised type II collagen from porcine cartilage nad cartilaginous fish. Type II collagen was cross-linked with 4arm and 8arm StarPEG. We hypothesise that pure type II collagen can be obtained from cartilaginous tissue and 8arm StarPEG crosslinking will increase the mechanical, biological and biomedical properties of collagen hydrogel. Materials and Methods: Tyep II collagen was extracted from porcine trachea, ear, articular cartilage and cartilaginous fish through acid-pepsin digestion at 4ºC. SDS-PAGE was used to reveal the number and size of collagen chains. Thermal stability was tested by differential scanning calorimetry (DSC). Enzymatic degradation was assessed by collagenase assay. TNBSA assay will be carried out to test the free amine group in cross-linked collagen hydrogel. Human chondrocyte cell phenotype maintenance will be assessed with proteina and gene assays. Results: Conclusions: Pure type II collagen can be extracted from porcine cartilage and cartilaginous fish. Further biological assays will be carried out to characterise collagen enzymatic degradation and thermal stability. The authors would like to thank Teagasc, Irish Agriculture and Food Development Authority, Funding agency for providing financial support for this project.

Differentiation of respiratory epithelium in a 3-dimensional co-culture with fibroblasts embedded in fibrin gel.

BackgroundTracheal tissue engineering is a promising option for the treatment of tracheal defects. In a previous study we proved the suitability of fibrin gel as a scaffold for tracheal tissue engineering. This study investigates whether the differentiation of respiratory epithelium can be increased by culturing epithelial cells in a three dimensional system containing fibroblasts embedded into fibrin gel.MethodsRespiratory epithelial cells were isolated from porcine trachea, seeded onto a fibrin gel and kept in air-liquid-interface culture for 33 days. Morphology as well as pan-cytokeratin, MUC5AC and claudin-1 expression of cells cultured on pure fibrin gel were compared to culture on gels containing fibroblasts.ResultsAfter two weeks, cells seeded on pure fibrin gel were multilayered, showed hyperproliferation and dedifferentiation. Co-cultured cells built up a pseudostratified epithelium. The differentiation and organization of epithelial structure improved with respect to time. After four weeks, morphology of the co-cultured respiratory epithelium resembled native tracheal epithelium. Immunohistochemistry showed that respiratory epithelium co-cultured with fibroblasts had an increasing similarity of pan-cytokeratin expression compared to native trachea. Cells cultured without fibroblasts differed in pan-cytokeratin expression from native trachea and did not show any improvement of differentiation. Immunohistochemical staining of MUC5AC and claudin-1 proved seeded cells being respiratory epithelial cells.ConclusionsThis study indicates that adding fibroblasts to fibrin gel positively influences the differentiation of respiratory epithelium.

Development of a Bronchial Wall Model: Triple Culture on a Decellularized Porcine Trachea.

In vitro coculture models mimicking the bronchial barrier are a significant step forward in investigating the behavior and function of the upper respiratory tract mucosa. To date, mostly synthetic materials have been used as substrates to culture the cells. However, decellularized tissues provide a more in vivo-like environment based on the native extracellular matrix. In this study, an in vitro, bronchial wall coculture model has been established using a decellularized, porcine luminal trachea membrane and employing three relevant human cell types. The tissue was decellularized and placed in plastic transwell supports. The human bronchial epithelial cell line, 16HBE14o-, was seeded on the apical side of the membrane with the human lung fibroblast cell line, Wi-38, and/or the microvascular endothelial cell line, ISO-HAS-1, seeded on the basolateral side. Transepithelial electrical resistance (TER) was measured over 10 days and tight/adherens junctions (ZO-1, occludin/β-catenin) were studied through immunofluorescence. Scanning electron microscopy (SEM) was performed to evaluate microvilli and cilia formation. All cultures grew successfully on the membrane. TER values of 555 Ω·cm(2) (±21, SEM) were achieved in the monoculture. Cocultures with fibroblasts reached 565 Ω·cm(2) (±41, SEM), with endothelial cells at 638 Ω·cm(2) (±37, SEM), and the triple culture achieved 552 Ω·cm(2) (±38, SEM). ZO-1, occludin, and β-catenin were expressed in 16HBE14o- under all culture conditions. Using SEM, a dense microvilli population was found. Prominent cell-cell contacts and clusters of emerging cilia could be identified. Fibroblasts and endothelial cells strengthened the formation of a tight barrier by the 16HBE14o-. Thus, the coculture of three relevant cell types in combination with native decellularized scaffolds as a substrate approaches more closely the in vivo situation and could be used to study mechanisms of upper respiratory damage and regeneration.

Perfusion-Decellularization of Porcine Lung and Trachea for Respiratory Bioengineering.

Decellularization of native organs may provide an acellular tissue platform for organ regeneration. However, decellularization involves a trade-off between removal of immunogenic cellular elements and preservation of biomechanical integrity. We sought to develop a bioartificial scaffold for respiratory tissue engineering by decellularization of porcine lungs and trachea while preserving organ architecture and vasculature. Lung-trachea preparations from 25 German Landrace pigs were perfused in a modified Langendorff circuit and decellularized by an SDC (sodium deoxycholate)-based perfusion protocol. Decellularization was evaluated by histology and fluorescence microscopy, and residual DNA quantified spectrophotometrically and compared with controls. Airway compliance was evaluated by endotracheal intubation and mechanical ventilation to simulate physiological breathing-induced stretch. Structural integrity was evaluated by bronchoscopy and biomechanical stress/strain analysis by measuring passive tensile strength, all compared with controls. Decellularized lungs and trachea lacked intracellular components but retained specific collagen fibers and elastin. Quantitative DNA analysis demonstrated a significant reduction of DNA compared with controls (32.8 ± 12.4 μg DNA/mg tissue vs. 179.7 ± 35.8 μg DNA/mg tissue, P < 0.05). Lungs and trachea decellularized by our perfusion protocol demonstrated increased airway compliance but preserved biomechanical integrity as compared with native tissue. Whole porcine lungs-tracheae can be successfully decellularized to create an acellular scaffold that preserves extracellular matrix and retains structral integrity and three-dimensional architecture to provide a bioartifical platform for respiratory tissue engineering.

Electromechanical reshaping of ex vivo porcine trachea.

The trachea is a composite cartilaginous structure particularly prone to various forms of convexities. Electromechanical reshaping (EMR) is an emerging technique used to reshape cartilaginous tissues by applying electric current in tandem with imposed mechanical deformation to achieve shape change. In this study, EMR was used to reshape tracheal cartilage rings to demonstrate the feasibility of this technology as a potentially minimally invasive procedure to alter tracheal structure. Controlled laboratory study using ex vivo porcine tracheae. The natural concavity of each porcine tracheal ring was reversed around a cork mandrel. Two pairs of electrodes were inserted along the long axis of the tracheal ring and placed 1.5 millimeters from the midline. Current was applied over a range of voltages (3 volts [V], 4V, and 5V) for either 2 or 3 minutes. The degree of EMR-induced reshaping was quantified from photographs using digital techniques. Confocal imaging with fluorescent live and dead assays was conducted to determine viability of the tissue after EMR. Specimens that underwent EMR for 2 or 3 minutes at 4V or 5V were observed to have undergone significant (P < .05) reshaping relative to the control. Viability results demonstrated that EMR reshaping occurs at the expense of tissue injury, although the extent of injury is modest relative to conventional techniques. EMR reshapes tracheal cartilage rings as a function of voltage and application time. It has potential as a minimally invasive and cost-efficient endoscopic technology to treat pathologic tracheal convexities. Given our findings, consideration of EMR for use in larger ex vivo tracheal segments and animal studies is now plausible.

Isolation and immobilization of influenza virus-specific N-SA-α-2,3-Gal receptors using magnetic nanoparticles coated with chitosan and Maackia amurensis lectin.

Avian influenza viruses preferentially bind to sialic acid alpha-2,3-galactose (N-SA-α-2,3-Gal) receptors on epithelial cells. Herein, we describe a procedure we have developed for isolation of N-SA-α-2,3-Gal receptors from porcine trachea using magnetic nanoparticles (NPs) coated with chitosan (NP-Ch) and functionalized with Maackia amurensis lectin (NP-lectin). Magnetic nanoparticles were coated with chitosan in a one-step co-precipitation, and then M. amurensis lectin was immobilized covalently using glutaraldehyde. Lectin coated nanoparticles were incubated with sialic acid enriched fraction of tracheal homogenate, and N-SA-α-2,3-Gal receptor was extracted under magnetic field in two cycles. The presence of 66.4 kDa protein was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The interaction of immobilized receptor (NP-Ch-R) with M. amurensis lectin (NP-Ch-R-L) was demonstrated by Fourier transform infrared spectrometry (FTIR) and thermogravimetric analysis (TGA).

Evaluation of recombinant Mycoplasma hyopneumoniae P97/P102 paralogs formulated with selected adjuvants as vaccines against mycoplasmal pneumonia in pigs

Pig responses to recombinant subunit vaccines containing fragments of eight multifunctional adhesins of the Mycoplasma hyopneumoniae (Mhp) P97/P102 paralog family formulated with Alhydrogel® or Montanide™ Gel01 were compared with a commercial bacterin following experimental challenge. Pigs, vaccinated intramuscularly at 9, 12 and 15 weeks of age with either of the recombinant formulations (n=10 per group) or Suvaxyn® M. hyo (n=12), were challenged with Mhp strain Hillcrest at 17 weeks of age. Unvaccinated, challenged pigs (n=12) served as a control group. Coughing was assessed daily. Antigen-specific antibody responses were monitored by ELISA in serum and tracheobronchial lavage fluid (TBLF), while TBLF was also assayed for cytokine responses (ELISA) and bacterial load (qPCR). At slaughter, gross and histopathology of lungs were quantified and damage to epithelial cilia in the porcine trachea was evaluated by scanning electron microscopy. Suvaxyn® M. hyo administration induced significant serological responses against Mhp strain 232 whole cell lysates (wcl) and recombinant antigen F3P216, but not against the remaining vaccine subunit antigens. Alhydrogel® and Montanide™ Gel01-adjuvanted antigen induced significant antigen-specific IgG responses, with the latter adjuvant eliciting comparable Mhp strain 232 wcl specific IgG responses to Suvaxyn® M. hyo. No significant post-vaccination antigen-specific mucosal responses were detected with the recombinant vaccinates. Suvaxyn® M. hyo was superior in reducing clinical signs, lung lesion severity and bacterial load but the recombinant formulations offered comparable protection against cilial damage. Lower IL-1β, TNF-α and IL-6 responses after challenge were associated with reduced lung lesion severity in Suvaxyn® M. hyo vaccinates, while elevated pathology scores in recombinant vaccinates corresponded to cytokine levels that were similarly elevated as in unvaccinated pigs. This study highlights the need for continued research into protective antigens and vaccination strategies that will prevent Mhp colonisation and establishment of infection.

Immobilization of SA-α-2,6-Gal Receptors Related to Influenza on Magnetic Nanoparticles Coated with Chitosan

Influenza infection is carried out due to the virus hemagglutinin recognizes host cell surface with terminal sialic acid (SA) linked receptors SA-α-2,6-Gal for human strain.Sambucus nigralectin has structural similarity to the viral hemagglutinin. Magnetic nanoparticles (MNP) coated with chitosan can be used as support for the study of these receptors. The goal of this study was to extract the SA-α-2,6-Gal receptors of porcine trachea for their immobilization on magnetic nanoparticles coated with chitosan. The extraction was carried out based on affinity ofSambucus nigralectin to SA-α-2,6-Gal receptors. It was possible to immobilize up to 76% of SA-α-2,6-Gal receptors, with a molecular weight at 88.4 kDa for more representative protein. The presence of the receptors was confirmed trough FTIR analysis. Magnetic functionalized nanoparticles showed superparamagnetic properties and an average diameter around 10 nm. These results may be used to evaluate the interaction between functionalized nanoparticles and specific lectin or hemagglutinin of influenza virus as model of study virus-receptor.

Innate immune response to a H3N2 subtype swine influenza virus in newborn porcine trachea cells, alveolar macrophages, and precision-cut lung slices

Viral respiratory diseases remain of major importance in swine breeding units. Swine influenza virus (SIV) is one of the main known contributors to infectious respiratory diseases. The innate immune response to swine influenza viruses has been assessed in many previous studies. However most of these studies were carried out in a single-cell population or directly in the live animal, in all its complexity. In the current study we report the use of a trachea epithelial cell line (newborn pig trachea cells – NPTr) in comparison with alveolar macrophages and lung slices for the characterization of innate immune response to an infection by a European SIV of the H3N2 subtype. The expression pattern of transcripts involved in the recognition of the virus, interferon type I and III responses, and the host-response regulation were assessed by quantitative PCR in response to infection. Some significant differences were observed between the three systems, notably in the expression of type III interferon mRNA. Then, results show a clear induction of JAK/STAT and MAPK signaling pathways in infected NPTr cells. Conversely, PI3K/Akt signaling pathways was not activated. The inhibition of the JAK/STAT pathway clearly reduced interferon type I and III responses and the induction of SOCS1 at the transcript level in infected NPTr cells. Similarly, the inhibition of MAPK pathway reduced viral replication and interferon response. All together, these results contribute to an increased understanding of the innate immune response to H3N2 SIV and may help identify strategies to effectively control SIV infection.