Extracellular proteasome in the alveolar space: characterisation and function under physiological and pathophysiological condition: an observational study
We hypothesised that 20S proteasome is present and functional in the extracellular alveolar space of healthy subjects and patients with Acute Respiratory Distress Syndrome (ARDS), sarcoidosis and in the alveolar space after lung transplantation in humans.
Ethics approval received from the local ethics committee (Vorsitzender der Ethikkommission, Institut für Pharmakologie, Universitätsklinikum Essen) on the 9th December 2002 (ref: 01-97-1697).
This study is an observational, single-centre study. The aim of this study is the description and characterisation of the extracellular alveolar proteasome in healthy and sick subjects.
Primary study design
Secondary study design
Patient information sheet
Extracellular proteasome in the alveolar space
Healthy caucasians subjects and patients with ARDS, sarcoidosis and patients after lung transplantation were included after approval of the local ethics committee and informed written consent.
Proteasomal activity will be measured in Broncho-Alveolar Lavage (BAL) supernatant from healthy subjects, patients with acute respiratory distress syndrome and lung transplantation using specific proteasomal fluorogenic substrates and I125 albumin, with and without specific proteasome inhibitors. After that the different enzyme activities of the study groups were compared with healthy subjects. Furthermore, gel filtration, western blot technique, Enzyme-Linked Immuno-Sorbent Assay (ELISA) and mass spectrometry, were applied for proteasome characterisation in the different study groups.
Primary outcome measures
1. Enzyme activity using specific proteasomal fluorogenic substrates and I125 albumin, with and without specific proteasome inhibitors
2. Detection of 20S proteasome with polyclonal antibody (western-blot)
3. Detection of immunoproteasome with LMP2 and LMP7 antibody (western-blot)
4. Gel filtration to evaluate the molecular weight of the extracellular proteasome in the bronchoalveolar space
5. Mass spectrometry of the gel filtration revealed hydrolysing activity and ELISA technique for the amount of extracellular, alveolar proteasome
Secondary outcome measures
No secondary outcome measures
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Acute respiratory distress syndrome:
1.1. Timing: acute onset
1.2. Oxygenation: Partial Pressure of Oxygen in Arterial Blood (PaO2)/Fraction of Inspired Oxygen (FiO2) ratio less than 200 mmHg (regardless of Positive End Expiratory Pressure [PEEP])
1.3. Chest radiograph: bilateral infiltrates seen on frontal chest radiograph
1.4. Pulmonary Artery Wedge (PAW): less than 18 mmHg when measured or no clinical evidence of left atrial hypertension
3. Lung transplantation: patient after lung transplantation were lavaged in a routine diagnostic, for the screening of organ rejection and infection
4. Aged 18 to 70 years, both genders
Target number of participants
300 subjects, including healthy subjects and patients with acute respiratory distress syndrome, sarcoidosis and lung transplantation.
Participant exclusion criteria
1. Acute respiratory distress syndrome: contraindication against bronchoscopy
2. Sarcoidosis: contraindication against bronchoscopy
3. Lung transplantation: contraindication against bronchoscopy
4. Healthy subjects:
4.1. Contraindication against bronchoscopy
4.2. Any lung diseases
4.5. Coronary heart disease
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Klinik fur Anasthesiologie und Intensivmedizin
German Research Council (Deutsche Forschungsgemeinschaft [DFG]) (Germany)
c/o Dr. Simone Mueller
German Research Council (Deutsche Forschungsgemeinschaft [DFG]) (Germany) (ref: PE 301/4-1) - submitted
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting
Initial findings at
Sixt SU, Beiderlinden M, Jennissen HP, Peters J, Extracellular proteasome in the human alveolar space: a new housekeeping enzyme?, Am. J. Physiol. Lung Cell Mol. Physiol., 2007, 292, 5, L1280-8, doi: 10.1152/ajplung.00140.2006.