Quantitation of transforming growth factor-beta in plasma and pulmonary epithelial lining fluid of sheep experimentally infected with maedi-visna virus

Single use and conventional bronchoscopes for Broncho alveolar lavage (BAL) in research: a comparative study (NCT 02515591)

Background

Broncho alveolar lavage (BAL) is widely used for investigative research to study innate, cellular and humoral immune responses, and in early phase drug trials. Conventional (multiple use) flexible bronchoscopes have time and monetary costs associated with cleaning, and carries a small risk of cross infection. Single use bronchoscopes may provide an alternative, but have not been evaluated in this context.

Methods

Healthy volunteers underwent bronchoscopy at a day-case clinical research unit using the Ambu® aScope^TM single-use flexible intubation bronchoscope. Broncho alveolar lavage was performed from a sub segmental bronchus within the right middle lobe; a total of 200 ml of warmed normal saline was instilled then aspirated using handheld suction. BAL volume yield, cell yield and viability were recorded.

Results

Ten volunteers, (mean age 23 years, six male) participated. Bronchoscopies were carried out by one of two senior bronchoscopists, experienced in the technique of obtaining BAL for research purposes. The results were compared to 50 (mean age 23, 14 male) procedures performed using the conventional scope by the same two bronchoscopists. The total volume yield was significantly higher in the disposable group median 152 ml (IQR 141–166 ml) as compared to conventional 124 ml (110–135 ml), p = <0.01. The total cell yield and viability were similar in both groups, with no significant differences.

Conclusions

With single use bronchoscopes, we achieved a larger BAL volume yield than conventional bronchoscopes, with comparable cell yield and viability. Better volume yields can potentially reduce post procedure side effects such as pleuritic chest pain and cough. The risk of cross infection can be eliminated, providing reassurance to researchers and participants. Reduced maintenance requirements can be cost effective. These could potentially be used for early phase drug development studies.

Trial registration

This trial was registered prospectively in July 2015 with the National Clinical Trials register, with the following registration number assigned: NCT 02515591.

Equid herpesvirus 1: platelets and alveolar macrophages are potential sources of activated TGF-B1 in the horse

Cell mediated responses to Equid herpesvirus 1 (EHV-1) are of short duration in vivo and require considerable expansion to be detected in vitro. Raised serum levels of active transforming growth factor B (TGF-B1) have been shown to depress proliferative T cell responses in experimental infections with EHV-1 in ponies. The present work indicates that latent transforming growth factor B (TGF-B1) is present in circulating platelets, lymph node, bronchial epithelium and alveolar macrophages. Activation of platelets in vitro by thrombin resulted in the release of latent TGF-B1 from platelets, with a pg level of conversion to active TGF-B1, but virus alone did not activate TGF-B1. Exposure of circulating leucocytes to EHV-1 in vivo or in vitro does not result in detection of active TGF-B1 above residual levels that could be attributed to activation of platelets by manipulation. However, alveolar macrophages obtained by lavage at autopsy yield both latent and active TGF-B1 in ng quantities. Bronchial epithelium, and mesenteric lymph node leucocytes had equivalent levels of latent TGF-B1, but horses varied as to whether these tissues were a source of activated TGF-B1 and as to whether EHV-1 activated TGF-B1.

Transforming growth factor-beta 1 (TGF-beta1) expression in ovine lentivirus-induced lymphoid interstitial pneumonia

The aim of this study was to detect the localization of TGF-beta1 protein expression in normal sheep lungs and lungs with interstitial pneumonia associated with infection with maedi-visna virus (MVV). Immunohistochemical localization of TGF-beta1 was determined in 24 lungs of adult sheep naturally infected with MVV and six control lungs of seronegative sheep. The lungs of infected animals showed different lesional degrees: grade 0, no lesions; grade I, mild; grade II, moderate; grade III, severe. In normal lungs, TGF-beta1 was primarily expressed in airway epithelium, bronchial cartilage and glands, endothelial cells and smooth muscle of blood vessels, alveolar macrophages and type II pneumocytes. No staining was observed in alveolar interstitium. In MVV-infected sheep an increased number of positive alveolar and interstitial macrophages and staining of alveolar interstitium was observed in grade I, grade II and some grade III lesions. In grade III lesions an inverse relationship was found between TGF-beta1 staining and smooth muscle hyperplasia. Small lymphoid aggregates, in general, showed strong reactivity, whereas larger ones showed weak reactivity, mainly associated with follicular areas. No significant differences in the staining intensity of airways and blood vessels were observed between control and MVV lungs. The increased expression of TGF-beta1 in early maedi lesions and its down-regulation in more advanced disease suggest the operation of a temporal regulatory mechanism whereby early expression may lead to the smooth muscle hyperplasia which develops during the disease. The striking inverse relationship between TGF-beta1 expression and follicle organization is intriguing and warrants further investigation.