Frédéric Billen

CCDC39 is required for assembly of inner dynein arms and the dynein regulatory complex and for normal ciliary motility in humans and dogs

Primary ciliary dyskinesia (PCD) is an inherited disorder characterized by recurrent infections of the upper and lower respiratory tract, reduced fertility in males and situs inversus in about 50% of affected individuals (Kartagener syndrome). It is caused by motility defects in the respiratory cilia that are responsible for airway clearance, the flagella that propel sperm cells and the nodal monocilia that determine left-right asymmetry. Recessive mutations that cause PCD have been identified in genes encoding components of the outer dynein arms, radial spokes and cytoplasmic pre-assembly factors of axonemal dyneins, but these mutations account for only about 50% of cases of PCD. We exploited the unique properties of dog populations to positionally clone a new PCD gene, CCDC39. We found that loss-of-function mutations in the human ortholog underlie a substantial fraction of PCD cases with axonemal disorganization and abnormal ciliary beating. Functional analyses indicated that CCDC39 localizes to ciliary axonemes and is essential for assembly of inner dynein arms and the dynein regulatory complex.

Comparison of the value of measurement of serum galactomannan and Aspergillus-specific antibodies in the diagnosis of canine sino-nasal aspergillosis.

Serology is currently used for the diagnosis of canine sino-nasal aspergillosis (SNA). However, the accuracy of serological testing using commercially available, standardized purified antigen preparations of Aspergillus (CAPurAspAg) has only been poorly documented. The aim of the present study was to assess the diagnostic value of an agar-gel double immunodiffusion (AGDD) test and an anti-Aspergillus IgG ELISA, using CAPurAspAg and the commercially available Platelia test for the detection of serum galactomannan. Sera from 17 dogs with SNA, 18 dogs with a nasal tumour (NT), 11 dogs with lymphoplasmacytic rhinitis (LPR) and 33 control dogs were tested with the 3 methods. AGDD result was positive in 76.5% of dogs with SNA, whereas all sera from dogs with non-fungal nasal disease and control dogs were negative. A positive IgG ELISA result was obtained in 88% of dogs with SNA and in 18% of dogs with LPR. All patients with NT and control dogs had a negative IgG ELISA result. The Platelia test was positive in 24% of dogs with SNA, 11% of dogs with NT, 9% of dogs with LPR and 24% of control dogs. The results of this study suggest that (1) the detection of serum Aspergillus-specific antibodies with AGDD or ELISA, using CAPurAspAg, provides excellent specificity and good sensitivity, (2) the specificity is higher for AGDD (100%) than for ELISA (96.8%) while sensitivity is higher for ELISA (88.2%) than for AGDD (76.5%) and (3) serum galactomannan quantification with the Plateliat test is unreliable for the diagnosis of canine SNA.

Prophylactic effects of omega-3 polyunsaturated fatty acids and luteolin on airway hyperresponsiveness and inflammation in cats with experimentally-induced asthma.

The aim of this study was to assess the preventive effects of omega-3 polyunsaturated fatty acids (omega3 PUFA) and luteolin supplementation on allergen-induced inflammation in eight Ascaris suum (AS)-sensitised cats. Airway responsiveness (AR) tests were performed and venous blood and bronchoalveolar lavage fluid (BALF) collected before and following a single (AS-stimulated) allergen exposure, as well as at the end of a 4-week treatment period, which was followed by a second AS-challenge. The omega6/omega3 fatty acid ratio in erythrocyte membranes, BALF cytology, AR to carbachol, and BALF lipoxin A(4) (LXA(4)), an endogenous inhibitor of inflammation, were assessed at each time point. Compared to respective unstimulated values, AS-challenged cats exhibited a significant rise in BALF eosinophil percentage and there was a trend to increased BALF total cell counts, increased AR and reduced BALF LXA(4) concentrations. The significant decrease in the blood omega6/omega3 ratio seen after supplementation demonstrated that omega3 PUFA were efficiently absorbed. No changes in BALF cytology were found between untreated and treated AS-stimulated cats, but BALF LXA(4) levels were significantly elevated and AR significantly decreased following supplement intake. The study suggests that omega3-luteolin supplementation may have some beneficial effects on AR through a LXA(4)-dependent pathway in cats with experimentally-induced asthma.

Effect of sampling method and incubation temperature on fungal culture in canine sinonasal aspergillosis.

OBJECTIVES To evaluate the most appropriate sampling procedure and the effect of incubation temperature on fungal culture in the diagnosis of canine sinonasal aspergillosis (SNA). METHODS Sixteen dogs with SNA and 20 dogs with non-fungal nasal disease entered a prospective study. Nasal secretions and mucosal biopsies were collected in all dogs. Fungal plaques were also sampled in dogs with SNA. Each specimen was taken in duplicate from each dog and incubated at room temperature and 37 degrees C. RESULTS In dogs with SNA, nasal secretions, mucosal biopsies and fungal plaques yielded fungal growth at room temperature in one, one and seven dogs, respectively, whereas fungal growth was obtained at 37 degrees C in three, 12 and 14 dogs, respectively. No specimen collected from any dog with non-fungal nasal disease yielded fungal growth at room temperature or at 37 degrees C. CLINICAL SIGNIFICANCE The diagnosis of canine SNA is more likely to be confirmed following culture of mucosal biopsies or fungal plaques than nasal secretions sampled blindly with swabs. Incubating cultures at 37 degrees C is more likely to provide a diagnostic outcome than when samples are cultured at room temperature. Fungal culture of nasal specimens has good specificity for the diagnosis of SNA in dogs.

Salmeterol or doxycycline do not inhibit acute bronchospasm and airway inflammation in cats with experimentally-induced asthma

The objective of this study was to determine if inhaled salmeterol, a long-acting β(2)-adrenergic agonist, and oral doxycycline, a tetracycline antibiotic displaying matrix metalloproteinase (MMP) inhibitory activity, reduce airway inflammation and obstruction in cats with experimentally-induced asthma. Eight Ascaris suum (AS)-sensitised cats were enrolled in a prospective study in which they underwent four AS-challenges at 1 month intervals. The challenged animals were given no treatment or were treated on 4 consecutive days with either: (1) oral prednisolone (1mg/kg twice daily), (2) inhaled salmeterol (50 μg twice daily), or (3) oral doxycycline (5mg/kg twice daily), according to a randomised cross-over design. Inhibition of allergen-induced early (EAR) and late (LAR) asthmatic reactions were assessed by barometric whole-body plethysmography. Cytology and measurement of MMP-2 and -9 activities were carried out on bronchoalveolar lavage fluid (BALF). Although none of the treatments prevented the EAR, prednisolone treatment inhibited the LAR. Relative to untreated cats, the eosinophil percentage and MMP-2 activity in BALF were significantly reduced following prednisolone treatment (P<0.05). Short-term therapy with either salmeterol or doxycycline had no effect on the EAR or LAR or on airway inflammation. Given the chronic nature of this disease in cats, long-term therapy may be required to produce more favourable functional and clinical outcomes.

Primary ciliary dyskinesia and situs inversus in a young dog

THE triad of situs inversus, bronchiectasis and rhinosinusitis in the same individual is known as Siewert-Kartagener syndrome ([Carlen and Stenram 2005][1]) or immotile cilia syndrome ([Neil and others 2002][2]). This short communication describes the investigation and diagnosis of Siewert-

Potential role of Alternaria and Cladosporium species in canine lymphoplasmacytic rhinitis.

OBJECTIVES To evaluate the possible role of Alternaria and Cladosporium species in the pathogenesis of canine lymphoplasmacytic rhinitis by comparing the amount of specific fungal DNA in nasal mucosal biopsies between dogs without nasal neoplasia and those with lymphoplasmacytic rhinitis or nasal neoplasia. METHODS Quantitative real-time polymerase chain reaction (qPCR) assays detecting DNA from Alternaria and Cladosporium fungi were applied to nasal mucosal biopsies collected from dogs with lymphoplasmacytic rhinitis (n = 8), dogs with nasal neoplasia (n = 10) and control animals (n = 10). A copy number for each sample was calculated using a standard curve of known copy number and differences amongst groups were assessed using Kruskal-Wallis tests. RESULTS No significant difference was found between the groups. Low levels of Alternaria DNA (10-100 copies/PCR) were detected in one sample; very low levels of DNA (<10 copies/qPCR) were detected in 6 samples, and 21 samples were negative. Low levels of Cladosporium DNA were detected in 2 samples; very low levels of DNA in 18; and 8 were negative. CLINICAL SIGNIFICANCE Results of this study reveal that Alternaria and Cladosporium species are part of the canine nasal flora, and that these fungi are probably not involved in the pathogenesis of lymphoplasmacytic rhinitis.

Syncope secondary to transient atrioventricular block in a German shepherd dog with dilated cardiomyopathy and atrial fibrillation.

This case report describes transient atrioventricular block as the etiology for syncopal events in a 6-year-old male German shepherd dog with atrial fibrillation and dilated cardiomyopathy. The arrhythmia diagnosis was obtained via Holter monitoring. Medical treatment with a sustained-release preparation of theophylline, as an additive to the standard congestive heart failure treatment (benazepril, furosemide and pimobendan) may have contributed to temporary remission of the syncopal events. However, the congestive heart failure progressed and the dog was euthanized. Veterinarians should be aware of the possibility of transient atrioventricular block causing syncope in dogs with DCM and AF and should be careful in empirically lowering the ventricular response rate if these dogs present with syncopal episodes.

Removal of oesophageal foreign bodies: comparison between oesophagoscopy and oesophagotomy in 39 dogs

OBJECTIVES To compare complication rates and outcomes after removal of oesophageal foreign bodies by endoscopy or by oesophagotomy. METHODS Retrospective evaluation of medical records of dogs with oesophageal foreign bodies treated by endoscopy and/or oesophagotomy. Postoperative clinical signs, management, length of hospitalisation, type and rate of complications, and time interval to return to eating conventional diet were compared. RESULTS Thirty-nine dogs diagnosed with oesophageal foreign bodies between 1999 and 2011 were included in the study. Most common breeds included West Highland white terrier, Jack Russell terrier and shih-tzu. Successful endoscopic removal was possible in 24 out of 32 cases (Group 1), while surgical removal was successful in 15 out of 15 cases (7 of which had unsuccessful attempts at endoscopic removal) (Group 2). Length of hospitalisation, time to removal of gastrostomy tube and time to eat conventional diet did not differ between the groups. After foreign body removal, the incidence of oesophagitis, oesophageal stricture and perforation observed during repeated endoscopy were similar between the groups. CLINICAL SIGNIFICANCE In this retrospective study, removal of oesophageal foreign bodies either by oesophagoscopy or oesophagotomy had a similar outcome.

Clinical Findings and Prevalence of the Mutation Associated with Primary Ciliary Dyskinesia in Old English Sheepdogs

Background Primary ciliary dyskinesia (PCD) is generally a recessively inherited disorder characterized by dysfunction of motile cilia. A mutation in a new causative gene (CCDC39) has been identified in the Old English Sheepdog (OES). Objectives To describe the clinical findings and the molecular changes of affected dogs and estimate the worldwide prevalence of the mutation in a large cohort of OES. Animals 578 OES, including 28 affected and 550 clinically healthy dogs. Methods This retrospective study reviewed the data of OES diagnosed with PCD and OES tested for the mutation. Clinical data including results of physical examination and further investigations were obtained on 11/28 dogs. CCDC39 expression was assessed by qRT‐PCR and Western blot analysis in affected dogs and healthy dogs. DNA was extracted on 561/578 dogs and a genetic test by Taqman technology was developed to genotype the CCDC39 mutation in these dogs. Results Clinical findings were recurrent nasal discharge and cough, pyrexia, leucocytosis, and bronchopneumonia. Ultrastructural defects were characterized by central microtubular abnormalities and decreased number of inner dynein arms (IDAs). Molecular analysis revealed a reduced expression of CCDC39 RNA and an absence of CCDC39 protein in affected dogs compared to healthy dogs. The mutation was more frequent in nonrandomly selected European OES population with a higher proportion of carriers (19%) compared to non‐European dogs (7%). Conclusion and Clinical Importance CCDC39 mutation is dispersed in a worldwide population and is responsible for PCD in this breed. Genetic testing might enable control of this disease.