Dog Lung Research Articles

Greater virulence of highly pathogenic H5N1 influenza virus in cats than in dogs.

Highly pathogenic H5N1 influenza virus continues to infect animals and humans. We compared the infectivity and pathogenesis of H5N1 virus in domestic cats and dogs to find out which animal is more susceptible to H5N1 influenza virus. When cats and dogs were infected with the H5N1 virus, cats suffered from severe outcomes including death, whereas dogs did not show any mortality. Viruses were shed in the nose and rectum of cats and in the nose of dogs. Viruses were detected in brain, lung, kidney, intestine, liver, and serum in the infected cats, but only in the lung in the infected dogs. Genes encoding inflammatory cytokines and chemokines, Toll-like receptors, and apoptotic factors were more highly expressed in the lungs of cats than in those of dogs. Our results suggest that the intensive monitoring of dogs is necessary to prevent human infection by H5N1 influenza virus, since infected dogs may not show clear clinical signs, in contrast to infected cats.

Effect of lung ischemic preconditioning on expression of aquaporin-1 during lung ischemia-reperfusion induced by cardiopulmonary bypass in dogs

Objective To investigate the effect of lung ischemic preconditioning (IP) on the expression of aquaporin-1 (AQP1) during lung ischemia-reperfusion (I/R) induced by cardiopulmonary bypass (CPB) in dogs.Methods Twelve adult mongrel dogs,weighing 15-20 kg,were randomly divided into 2 groups (n =6 each):lung I/R (group I/R) and ischemic preconditioning group (group IP).The left pulmonary artery was occluded at 10 min of off-pump CPB and mechanical ventilation was stopped in the left lung,60 min later occlusion was released,and mechanical ventilation was recovered to establish the model of left lung ischemia-reperfusion injury induced by CPB.In group IP,lung ischemic preconditioning was induced by 2 cycles of 5 min ischemia followed by 5 min reperfusion before occlusion of the left pulmonary artery.Before CPB (T1),immediately after occlusion of the left pulmonary artery (T2),at the end of CPB (T3),and at 2 h after the end of CPB (T4),pulmonary specimens were collected for determination of wet to dry lung weight ratio (W/D ratio) and expression of AQP1 and for examination of the pathological changes of lungs which were scored.Respiration index (RI),oxygenation index (OI),and alveolar-arterial oxygen tension difference (P(A-a)O2) were calculated at T1,T3 and T4,and the left pulmonary alveolar fluid clearance (AFC) was calculated at T4.Results Compared with group I/R,P(A-a) O2 and RI were significantly decreased,OI was increased,W/D ratio and pathological scores were decreased,the expression of AQP1 was up-regulated,and the AFC was increased at T3 and T4 in group IP.The pathological changes of the lung were significantly attenuated in group IP as compared with group I/R.Conclusion The mechanism by which lung ischemic preconditioning mitigates lung I/R injury induced by CPB is related to upregulation of the expression of AQP1 in dog lung tissues. Key words: Ischemic preconditioning; Cardiopulmonary bypass ; Reperfusion injury ; Lung ; Aquaporin 1

Lung inflammation associated with acute necrotizing pancreatitis in dogs (LB513)

There is evidence that dogs suffering from acute necrotizing pancreatitis (ANP) can develop respiratory disease. However, there are no data describing the lung histopathology in clinical cases of ANP in dogs. Therefore, we hypothesized that lungs of dogs that died due to ANP (n=21) will be inflamed along with recruitment of PIMs, a pro‐inflammatory cell normally present in ruminants and equines, compared to lungs of control dogs (n=6). Histologic sections of the pancreas graded independently by two blinded pathologists showed the presence of necrosis and infiltration of inflammatory cells (scores 3‐10) whereas control dogs received a score of 0. Lungs from ANP dogs showed no (score of 0/6) to moderate (score 3/6) inflammation, but there was no statistical difference between the lung histological score of the control (median ± SEM: 0.5±0.3) and the ANP (median ± SEM: 1.5±0.2) dogs. However, immunohistochemistry revealed an increase in the numbers of septal macrophages/monocytes in lungs of ANP dogs (median ± SEM: 138±49) compared to control dogs (median ± SEM: 1.5±0,2; p<0,01). There was a moderate correlation (r=0.46) between the recruitment of macrophages/monocytes in the lungs and the total inflammatory cells score in the pancreas of ANP dogs. Only ANP dogs showed expression of vWF in alveolar septal capillaries and septal inflammatory cells. iNOS was expressed only in alveolar macrophages of ANP dogs. TLR4 and IL6 were variably expressed and localized in alveolar macrophages and septal inflammatory cells in lungs from both ANP and control dogs. We conclude that dogs suffering from ANP have pronounced lung inflammation along with recruitment of PIMs and increased expression of vWF. The PIMs may increase the susceptibility of the host to lung inflammation in response to circulating endotoxins.Grant Funding Source: Supported by Companion Animal Health Fund

2:15 PM; Abstract No. 51 - Pharmacokinetics study of bronchial artery infusion chemotherapy in dog lung on the basis of microdialysis technique

2:15 PM; Abstract No. 51 - Pharmacokinetics study of bronchial artery infusion chemotherapy in dog lung on the basis of microdialysis technique

Detection of Anaplasma phagocytophilum in red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) from Brandenburg, Germany

Anaplasma phagocytophilum is an obligate intracellular and tick-transmitted bacterium, which causes granulocytic anaplasmosis in animals and humans. Although infection with A. phagocytophilum in domestic animals and vector ticks is documented, there is sparse information on the occurrence of A. phagocytophilum in wild animals. Red foxes (Vulpes vulpes) as well as raccoon dogs (Nyctereutes procyonoides) are wildlife species highly abundant in certain areas of Germany and represent a potential wildlife reservoir for zoonotic diseases. To obtain data about the occurrence of A. phagocytophilum in these animals, red fox and raccoon dog carcasses (hunted or found dead) were collected from January to September 2009 in the Federal State of Brandenburg, Germany. Lung tissue samples were subjected to DNA extraction and were examined for the presence of A. phagocytophilum DNA by means of real-time PCR. Anaplasma phagocytophilum was detected in 10 out of 122 (8.2%) lungs of red foxes and in 3 out of 13 (23%) lungs of raccoon dogs. To the best of our knowledge, A. phagocytophilum was detected for the first time in red foxes and raccoon dogs in Germany.

H3N2 canine influenza virus causes severe morbidity in dogs with induction of genes related to inflammation and apoptosis

Dogs are companion animals that live in close proximity with humans. Canine H3N2 influenza virus has been isolated from pet dogs that showed severe respiratory signs and other clinical symptoms such as fever, reduced body weight, and interstitial pneumonia. The canine H3N2 influenza virus can be highly transmissible among dogs via aerosols. When we analyzed global gene expression in the lungs of infected dogs, the genes associated with the immune response and cell death were greatly elevated. Taken together, our results suggest that canine H3N2 influenza virus can be easily transmitted among dogs, and that severe pneumonia in the infected dogs may be partially due to the elevated expression of genes related to inflammation and apoptosis.

Analysis of gene expression in canine idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) in dogs is a rare disease of unknown aetiology, seen in terrier breeds, particularly the West Highland white terrier (WHWT). The aim of this study was to determine pulmonary gene expression in canine IPF in order to gain insights into the pathogenesis of the disease and to identify possible biomarkers. Microarray analyses were conducted to determine gene expression profiles in the lungs of dogs with IPF and control dogs of various breeds. More than 700 genes were identified as having greater than two-fold difference in expression between the two groups. The significant biological functions associated with these genes were related to cellular growth and proliferation, developmental processes, cellular movement, cell to cell signalling and interaction, and antigen presentation. Altered levels of expression were confirmed by quantitative reverse transcriptase PCR for genes encoding chemokine (C–C) ligand (CCL) 2 (+4.9 times), CCL7 (+6.8 times), interleukin 8 (+4.32 times), chemokine (C–X–C) ligand 14 (+3.4 times), fibroblast activation protein (+4.7 times) and the palate, lung and nasal associated protein (PLUNC, −25 times). Serum CCL2 concentrations were significantly higher in WHWTs with IPF (mean 628.1pg/mL, interquartile range 460.3–652.7pg/mL) than unaffected WHWTs (mean 344.0pg/mL, interquartile range 254.5–415.5pg/mL; P=0.001). The results support CCL2 as a candidate biomarker for IPF in dogs.

Measurement of respiratory system compliance and respiratory system resistance in healthy dogs undergoing general anaesthesia for elective orthopaedic procedures: Lung compliance and resistance in healthy dogs

Objective The aim of this study was to investigate normal values for the dynamic compliance of the respiratory system (Crs) and respiratory system resistance (Rrs) in mechanically ventilated anaesthetized dogs. Study design Prospective clinical study. Animals Forty healthy dogs undergoing elective orthopaedic surgery. Body weight was (mean ± SD) 26.8 ± 10.7 kg (range: 1.9–45.0 kg), age 4.7 ± 2.9 years (range: 0.1–10.6 years). Methods Dogs were premedicated with acepromazine and methadone administered intramuscularly and anaesthesia induced with propofol intravenously. After endotracheal intubation the dog's lungs were connected to an appropriate breathing system depending on body weight and isoflurane in oxygen administered for maintenance of anaesthesia. The lungs were ventilated mechanically with variables set to maintain normocapnia (end‐tidal carbon dioxide concentration 4.7–6.0 kPa). Peak inspiratory pressure, Crs, Rrs, tidal volume, respiratory rate and positive end‐expiratory pressure were recorded at 5, 30, 60, 90 and 120 minutes after start of mechanical ventilation. Cardiovascular variables were recorded at time of collection of respiratory data. Results General additive modeling revealed the following relationships: Crs = [0.895 × body weight (kg)] + 8.845 and Rrs = [−0.0966 × body weight (kg)] + 6.965. Body weight and endotracheal tube diameter were associated with Crs (p < 0.001 and p = 0.002 respectively) and Rrs (p = 0.017 and p = 0.002 respectively), body weight being linearly related to Crs and inversely to Rrs. Conclusion and clinical relevance Body weight was linearly related to Crs while Rrs has an inverse linear relationship with body weight in mechanically ventilated dogs. The derived values of Crs and Rrs may be used for monitoring of lung function and ventilation in healthy dogs under anaesthesia.

Effect of rhythmic pressure waves on balancing airway basic mucus secretion in dogs

To investigate the effect of different pressure on mucin (MUC) secretion in dog airway mucus layer and explore the participation mechanisms. Totally 24 healthy dogs were randomly divided into 4 groups (n=6) after double-lumen endobronchial tube intubation. In group A the dogs were ventilated bilaterally with normal breathing frequency and pressure; In group B: one side of the dog lung did not ventilate, while the other side was excessively ventilated. In group C: the tension-sensitive cation channel (TRPV) 4 blocker Ruthenium Red (RR) was injected in advance, and ventilated as in group A. In group D: TRPV4 blocker RR was injected firstly, and then ventilated as in group B. After 12 h ventilation, we collected bronchoalveolar lavage fluid (BALF), tested MUC (2, 5AC, 5B) protein content by ELISA, and detected the transcription of MUC (2, 5AC, 5B) mRNA of bronchial lung tissue by RTPCR. Compared with the normal ventilation (A2) group, the protein level of MUC of excessive ventilation (B2) group was significantly higher, mainly MUC5AC (P<0.05); compared with the normal ventilation (A1) group, the protein level of MUC of no ventilation (B1) group was significantly decreased (P<0.05). After pretreatment with RR, the MUC protein level of group C1, C2 were significantly lower than that of group A1, A2 (P<0.05); the MUC protein level of group B2were significantly lower than that of group D2 (P<0.05). The MUC (2, 5AC and 5B) mRNA level was higher in excessive ventilation group (B2) than in normal ventilation group (A2). After pretreatment with RR, in comparison with group A1, A2, the MUC (2, 5AC and 5B) mRNA level of group C1, C2 declined; in comparison with group B2, the MUC (2, 5AC and 5B) mRNA level of group D2 declined. Rhythmic pressure waves may regulate and balance basic airway mucin secretion through activating the TRPV4 channel in dogs.

Separating in vivo mechanical stimuli for postpneumonectomy compensation: imaging and ultrastructural assessment

Following right pneumonectomy (PNX), the remaining lung expands and its perfusion more than doubles. Tissue and microvascular mechanical stresses are putative stimuli for compensatory lung growth and remodeling, but their relative contribution remains uncertain. To temporally separate expansion- and perfusion-related stimuli, we replaced the right lung of adult dogs with a customized inflated prosthesis. Four months later, the prosthesis was either acutely deflated (DEF) or kept inflated (INF). Thoracic high-resolution computed tomography (HRCT) was performed pre- and post-PNX before and after prosthesis deflation. Lungs were fixed for morphometric analysis ∼12 mo post-PNX. The INF prosthesis prevented mediastinal shift and lateral lung expansion while allowing the remaining lung to expand 27-38% via caudal elongation, associated with reversible capillary congestion in dependent regions at low inflation and 40-60% increases in the volumes of alveolar sepal cells, matrix, and fibers. Delayed prosthesis deflation led to further significant increases in lung volume, alveolar tissue volumes, and alveolar-capillary surface areas. At postmortem, alveolar tissue volumes were 33% higher in the DEF than the INF group. Lateral expansion explains ∼65% of the total post-PNX increase in left lung volume assessed in vivo or ex vivo, ∼36% of the increase in HRCT-derived (tissue + microvascular blood) volume, ∼45% of the increase in ex vivo septal extravascular tissue volume, and 60% of the increase in gas exchange surface areas. This partition agrees with independent physiological measurements obtained in these animals. We conclude that in vivo signals related to lung expansion and perfusion contribute separately and nearly equally to post-PNX growth and remodeling.

AP301, a synthetic peptide mimicking the lectin-like domain of TNF, enhances amiloride-sensitive Na+ current in primary dog, pig and rat alveolar type II cells

Pulmonary permeability oedema is a frequent complication in a number of life-threatening lung conditions, such as ALI and ARDS. Apart from ventilation strategies, no specific therapy yet exists for treatment of these potentially fatal illnesses. The oedema-reducing capacity of the lectin-like domain of TNF (TIP) and of synthetic peptides, mTIP and hTIP, which mimic the TIP domain of mouse and human TNF, have been demonstrated in various studies in rodents. Cell-based electrophysiological studies have revealed that the alveolar fluid clearing capacity of TNF and the TIP peptides is due to activation of the amiloride-sensitive Na+ current in alveolar epithelial cells and that the primary site of action is on the apical side of these cells.AP301, a synthetic cyclic peptide mimicking the TIP domain of human TNF is currently undergoing clinical trials as a therapy for pulmonary permeability oedema. AP301 has been shown to improve alveolar liquid clearance and lung function in a porcine model of ALI.For non-clinical regulatory assessment, dog, pig and rat are standard animal models; accordingly, pre-clinical toxicological and pharmacological safety studies have been conducted with AP301 in dogs and rats. Hitherto, no studies have assessed the pharmacodynamic effect of AP301 on primary canine or porcine type II AEC. The current study describes the effect of AP301 on the amiloride-sensitive Na+ current in type II AEC isolated from dog, pig and rat lungs. In whole cell patch clamp experiments with dog type II AEC, an increase in the amiloride-sensitive Na+ current from 3.7 pA to 49.4 pA was observed in the presence of AP301; in pig type II AEC, an increase from 10.0 pA to 159.6 pA was observed, and in rat AEC, from 6.9 pA to 62.4 pA. In whole cell patch clamp experiments in A549 cells, AP301-induced enhancement of the amiloride-sensitive current was eliminated when Na+ in the bath solution was replaced with N-methyl-d-glucamine (NMDG), and when the cells were pre-incubated with 5-aminoimidazole-4-carboxamide-1-ß-d-ribofuranoside (AICAR), an inhibitor of ENaC, but enhancement was unaffected by addition of cyclic nucleotide-gated (CNG) channel inhibitors Zn2+ or l-cis-diltiazem prior to AP301.These results provide strong evidence that AP301 activates the amiloride-sensitive Na+ current through ENaC in type II AEC from dog, pig and rat. To our knowledge, this is the first cell-based analysis of the oedema-clearing effect of AP301 observed in the porcine model of pulmonary oedema. Furthermore, the results validate the dog and pig models in non-clinical assessment of AP301.

Expression of Transforming Growth Factor Beta 1 in Lung Tissue during Cardiopulmonary Bypass-Induced Lung Injury in Dogs

Cardiopulmonary bypass (CPB) is a necessary technique for cardiac surgery and usually induces acute lung injury. Transforming growth factor β1 (TGFβ1) has been found to play a crucial role in the pathogenesis of inflammatory diseases; however, whether TGFβ1 is also involved in CPB-induced lung injury has yet to be determined. Therefore, we aimed to investigate the TGFβ1 expression in the lungs of dogs after CPB. A total of 36 healthy mongrel dogs were randomly assigned to control and CPB groups. Six dogs in each group were killed before, 30 min after the operation, and 60 min after the operation (T0, T1, and T2). Lung injury was evaluated by hematoxylin and eosin staining. Respiratory index (RI), oxygenation index (OI), malondialdehyde (MDA) content in the lung, and pulmonary permeability index (PPI) were determined at each time point. TGFβ1 expression was determined using real-time reverse transcription polymerase chain reaction and immunohistochemistry. There was a serious lung injury observed after CPB in dogs. RI increased and OI decreased in the dogs after CPB. The MDA content significantly increased after CPB; however, no significant change of MDA occurred in the control group. A significant increase of PPI was detected in CPB group at the T1 and T2 time points compared with that at the T0 time point. TGFβ1 expression in the lung was increased after CPB on both the mRNA and protein levels. Positive correlations between TGFβ1 mRNA level and MDA (r = 0.867, p < 0.01) and between TGFβ1 mRNA and PPI (r = 0.821, p < 0.01) were detected by linear correlation. The upregulation of TGFβ1 expression plays an important role in the development and progression of CPB-induced acute lung injury.

Separating in vivo mechanical stimuli for postpneumonectomy compensation: physiological assessment

Following right pneumonectomy (PNX), the remaining lung expands and its perfusion doubles. Tissue and microvascular mechanical stresses are putative stimuli for initiating compensatory lung growth and remodeling, but their relative contributions to overall compensation remain uncertain. To temporally isolate the stimuli related to post-PNX lung expansion (parenchyma deformation) from those related to the sustained increase in perfusion (microvascular distention and shear), we replaced the right lung of adult dogs with a custom-shaped inflated prosthesis. Following stabilization of perfusion and wound healing 4 mo later, the prosthesis was either acutely deflated (DEF group) or kept inflated (INF group). Physiological studies were performed pre-PNX, 4 mo post-PNX (inflated prosthesis, INF1), and again 4 mo postdeflation (DEF) compared with controls with simultaneous INF prosthesis (INF2). Perfusion to the remaining lung increased ~76-113% post-PNX (INF1 and INF2) and did not change postdeflation. Post-PNX (INF prosthesis) end-expiratory lung volume (EELV) and lung and membrane diffusing capacities (DL(CO) and DM(CO)) at a given perfusion were 25-40% below pre-PNX baseline. In the INF group EELV, DL(CO) and DM(CO) remained stable or declined slightly with time. In contrast, all of these parameters increased significantly after deflation and were 157%, 26%, and 47%, respectively, above the corresponding control values (INF2). Following delayed deflation, lung expansion accounted for 44%-48% of total post-PNX compensatory increase in exercise DL(CO) and peak O(2) uptake; the remainder fraction is likely attributable to the increase in perfusion. Results suggest that expansion-related parenchyma mechanical stress and perfusion-related microvascular stress contribute in equal proportions to post-PNX alveolar growth and remodeling.

Ventilation heterogeneity: small length scales, big challenges

the distribution of regional ventilation is heterogeneous in normal lung and increases dramatically under pathological conditions. This has been demonstrated both in humans and in animal models using a number of different imaging techniques. General anesthesia and mechanical ventilation can

How the Dream of an “Artificial Heart” Was Realized in Japan

How the Dream of an “Artificial Heart” Was Realized in Japan

Effects of Air Pollution on the Respiratory System Pathological Findings and Metals Content in Dog Lungs in Kawasaki City

Effects of Air Pollution on the Respiratory System Pathological Findings and Metals Content in Dog Lungs in Kawasaki City

Hypo-elastic model for lung parenchyma

A simple, isotropic, elastic constitutive model for the spongy tissue in lung is formulated from the theory of hypo-elasticity. The model is shown to exhibit a pressure dependent behavior that has been interpreted in the literature as indicating extensional anisotropy. In contrast, we show that this behavior arises naturally from an analysis of isotropic hypo-elastic invariants and is a result of non-linearity, not anisotropy. The response of the model is determined analytically for several boundary value problems used for material characterization. These responses give insight into both the material behavior as well as admissible bounds on parameters. The model predictions are compared with published experimental data for dog lung.

Characterization of iodinated adrenomedullin derivatives suitable for lung nuclear medicine

We have recently demonstrated the effectiveness of 99m-technetium adrenomedullin (AM) as a new molecular lung imaging agent that could provide significant advantages for the diagnosis and follow-up of disorders affecting the pulmonary circulation such as pulmonary embolism and pulmonary hypertension. Having the possibility to conjugate the targeting molecule with different radionuclides would offer more flexibility and potential advantages depending on clinical situations. Since various iodine isotopes are currently used in nuclear medicine and in pharmacological studies, we have evaluated which iodination method should be privileged in order to produce a good iodinated AM-derived nuclear medicine agent. Synthetic AM was labeled with iodine through chemical and lactoperoxidase oxidation methods. Position of the iodine atom onthe peptide was determined by MALDI-TOF mass spectrometry analysis following cyanogen bromide cleavage and carboxypeptidase Y digestion. Binding affinity of iodinated AM analogues was evaluated by competition and saturation binding experiments on dog lungpreparations. In this study, we demonstrated that, upon lactoperoxidase oxidation, iodination occurred at Tyr(1) and that this radioligand retained higher binding affinity and specificity over preparations obtained through chemical oxidation. These results emphasize the fact that even a small chemical modification, i.e. iodination, might deeply modify the pharmacological profile of a compound and support observations that the C-terminal tail of human AM plays an important role in the AM receptor binding process. Consequently, incorporation of a radionuclide to produce an AM-based nuclear medicine agent should privilege the N-terminus of the molecule.

Fine structure of tubular myelin from mammalian lungs

Tubular myelin and intracellular surfactant images are presented from human, rabbit, rat, and dog lung. The samples represent a long‐term study of normal as well as cystic fibrosis specimens. Tubular myelin is seen in its typical lattice‐like form as it is found on the extracellular surface. Surfactant within lamellar bodies is also shown with a unique relationship to mitochondria. Images from lung parenchyma and rabbit lung washes reveal the complex architecture of tubular myelin. Specimens are fixed with glutaraldehyde and secondary fix common to electron microscopy protocols. Comparative study of cystic fibrosis samples and normal lung did not reveal any differences in tubular myelin pattern. It is hoped that an analysis of these specimens will yield further information regarding cellular surfactant production, its arrangement, and its appearance on the cell surface in both the human normal and disease condition.

Isoflurane pre-treatment before cardiopulmonary bypass alleviates neutrophil accumulation in dog lungs

This study investigated the effect of isoflurane pretreatment on cardiopulmonary bypass (CPB)-related lung injury. Twelve dogs were randomly divided into two groups of six each. In one group, 1.0 minimum alveolar concentration (MAC) of isoflurane was dministered for 30 min before CPB, while the control group received no anaesthetic. Both groups then underwent 100 min of mild hypothermic CPB with 60-min aortic cross clamping. Haemodynamic parameters, respiratory mechanics and alveolar arterial oxygen difference (AaDO₂) were measured during the experiment. One hundred and fifty minutes after CPB, lung tissue samples from the non-dependent and dependent portions of the left and right lungs were harvested for polymorphonulear leukocyte (PMNs) counts. Following CPB, within the control group, pulmonary vascular resistance (PVR) was significantly increased at 60, 120 and 180 min after declamping, AaDO₂ deteriorated at 180 min post-declamping, and dynamic lung compliance (DLC) was reduced dramatically after declamping. Isoflurane pretreatment before CPB significantly reduced PVR compared to the controls. AaDO₂ was impaired at 180 min after declamping and DLC was decreased after declamping within the isoflurane group. No differences in AaDO₂ and DLC were found between the isoflurane and control groups. At 180 min after declamping, the PMN count in both the non-dependent and dependent regions of the isoflurane pre-treated lungs was significantly lower than that of the controls. Our results suggest that 30-min pre-treatment with 1.0 MAC isoflurane before CPB caused a reduction in PMN accumulation in the dog lungs, inhibition of increases in PVR, and it did not affect AaDO₂ in the early post-CPB stage.