Publications by authors named "Damijan Erzen"

11 Publications

  • Page 1 of 1

Mechanisms associated with increased physical activity in patients undergoing self-management behaviour modification in the randomised PHYSACTO trial.

ERJ Open Res 2021 Jan 29;7(1). Epub 2021 Mar 29.

University of Québec at Montréal/CIUSSS-NIM - Hôpital du Sacré-Coeur de Montréal, Montréal, Canada.

Introduction: In this analysis of the PHYSACTO® study, we assessed the efficacy of a self-management behaviour modification (SMBM) programme to improve physical activity (PA) levels, and the extent to which effects were mediated by readiness to change, motivation and confidence.

Methods: PHYSACTO® was a randomised, partially double-blind, parallel-group, 12-week trial to evaluate the effects of treatment on exercise capacity and PA. COPD patients received placebo, tiotropium 5 µg or tiotropium/olodaterol 5/5 µg, with or without exercise training, all with an SMBM intervention (the Living Well with COPD programme). Changes were assessed in readiness to change (stage of change visual analogue scale [VAS]), motivation (Treatment Self-Regulation Questionnaire [TSRQ]) and confidence (Perceived Competence Scale [PCS]) to engage in PA.

Results: PA was increased in all patients with complete PA data at Week 12 (n=262; +6038 steps·week, p<0.001). Significant increases were observed in patients' readiness to change (VAS 0.7 [0.6-0.8]), autonomous regulation (TRSQ 0.2 [0.1-0.3]) and confidence (PCS 0.5 [0.3-0.6]) (all p<0.01). Of note, 23% of the total effect of SMBM on steps·week was found to be mediated by increases in readiness to change, 5% by TSRQ autonomous regulation and 12% by PCS.

Conclusion: Our study demonstrated that an SMBM programme delivered to COPD patients increased PA, mediated by an improvement of three key hypothesised mechanisms of change: readiness to change, autonomous motivation and confidence. For the first time, this study shows that an SMBM programme can be successful in altering the mechanisms of change targeted by the intervention.
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http://dx.doi.org/10.1183/23120541.00533-2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8005679PMC
January 2021

Validity and responsiveness of the Daily- and Clinical visit-PROactive Physical Activity in COPD (D-PPAC and C-PPAC) instruments.

Thorax 2021 03 21;76(3):228-238. Epub 2021 Jan 21.

Department of Respiratory Diseases, University Hospital Leuven, Leuven, Belgium.

Background: The Daily-PROactive and Clinical visit-PROactive Physical Activity (D-PPAC and C-PPAC) instruments in chronic obstructive pulmonary disease (COPD) combines questionnaire with activity monitor data to measure patients' experience of physical activity. Their amount, difficulty and total scores range from 0 (worst) to 100 (best) but require further psychometric evaluation.

Objective: To test reliability, validity and responsiveness, and to define minimal important difference (MID), of the D-PPAC and C-PPAC instruments, in a large population of patients with stable COPD from diverse severities, settings and countries.

Methods: We used data from seven randomised controlled trials to evaluate D-PPAC and C-PPAC internal consistency and construct validity by sex, age groups, COPD severity, country and language as well as responsiveness to interventions, ability to detect change and MID.

Results: We included 1324 patients (mean (SD) age 66 (8) years, forced expiratory volume in 1 s 55 (17)% predicted). Scores covered almost the full range from 0 to 100, showed strong internal consistency after stratification and correlated as a priori hypothesised with dyspnoea, health-related quality of life and exercise capacity. Difficulty scores improved after pharmacological treatment and pulmonary rehabilitation, while amount scores improved after behavioural physical activity interventions. All scores were responsive to changes in self-reported physical activity experience (both worsening and improvement) and to the occurrence of COPD exacerbations during follow-up. The MID was estimated to 6 for amount and difficulty scores and 4 for total score.

Conclusions: The D-PPAC and C-PPAC instruments are reliable and valid across diverse COPD populations and responsive to pharmacological and non-pharmacological interventions and changes in clinically relevant variables.
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http://dx.doi.org/10.1136/thoraxjnl-2020-214554DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7892393PMC
March 2021

Effect of Bronchodilation, Exercise Training, and Behavior Modification on Symptoms and Physical Activity in Chronic Obstructive Pulmonary Disease.

Am J Respir Crit Care Med 2018 10;198(8):1021-1032

7 Research Institute of the McGill University Health Centre and McGill University, Montréal, Québec, Canada.

Rationale: Bronchodilation and exercise training (ExT) improve exercise tolerance in patients with chronic obstructive pulmonary disease (COPD); however, behavior modification is required to impact daily physical activity (PA).

Objectives: To assess whether tiotropium/olodaterol, with or without ExT, would improve exercise endurance time (EET) and PA compared with placebo in patients participating in a self-management behavior-modification (SMBM) program.

Methods: This was a 12-week, randomized, partially double-blind, placebo-controlled, parallel-group trial in patients with COPD (PHYSACTO; NCT02085161). All patients were enrolled into SMBM and randomized 1:1:1:1 to once-daily placebo, tiotropium 5 μg, tiotropium/olodaterol 5/5 μg, or tiotropium/olodaterol 5/5 μg plus 8 weeks ExT. EET, measured by endurance shuttle walk test after 8 weeks, was the primary endpoint. Additional endpoints assessed downstream effects on PA (measured via accelerometry), and activity-related dyspnea and difficulty (using validated patient-reported questionnaires).

Measurements And Main Results: SMBM plus tiotropium/olodaterol, with or without ExT, significantly improved EET at Week 8 versus SMBM plus placebo (treatment ratio vs. placebo: with ExT, 1.46; 95% confidence interval, 1.20-1.78; P = 0.0002; without ExT, 1.29; 95% confidence interval, 1.06-1.57; P = 0.0109). No significant increases in steps per day from baseline were observed over SMBM plus placebo at Week 12 (increase of 1,098) when other therapies were added. Adding tiotropium/olodaterol, with or without ExT, to SMBM reduced activity-related dyspnea versus placebo, whereas adding tiotropium/olodaterol plus ExT reduced activity-related difficulty.

Conclusions: Tiotropium/olodaterol, with or without ExT, improved EET in patients with COPD taking part in an SMBM program. Combination bronchodilation, with or without ExT, did not provide additional increases in objective PA compared with SMBM alone but did reduce PA-related dyspnea and difficulty. Clinical trial registered with www.clinicaltrials.gov (NCT02085161).
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http://dx.doi.org/10.1164/rccm.201706-1288OCDOI Listing
October 2018

Enhancing exercise tolerance and physical activity in COPD with combined pharmacological and non-pharmacological interventions: PHYSACTO randomised, placebo-controlled study design.

BMJ Open 2016 Apr 13;6(4):e010106. Epub 2016 Apr 13.

Boehringer Ingelheim (Canada) Ltd, Burlington, Ontario, Canada.

Introduction: Chronic obstructive pulmonary disease (COPD) is associated with exercise limitation and physical inactivity, which are believed to have significant long-term negative health consequences for patients. While a number of COPD treatments and exercise training programmes increase exercise capacity, there is limited evidence for their effects on physical activity levels, with no clear association between exercise capacity and physical activity in clinical trials. Physical activity depends on a number of behaviour, environmental and physiological factors. We describe the design of the PHYSACTO trial, which is investigating the effects of bronchodilators, either alone or with exercise training, in combination with a standardised behaviour-change self-management programme, on exercise capacity and physical activity in patients with COPD. It is hypothesised that bronchodilators in conjunction with a behaviour-change self-management programme will improve physical activity and that this effect will be amplified by the addition of exercise training.

Methods And Analysis: Patients are being recruited from 34 sites in Australia, New Zealand, the USA, Canada and Europe. Patients receiving a multicomponent intervention designed to support behaviour change related to physical activity are randomised to four treatment arms: placebo, tiotropium, tiotropium+olodaterol, and tiotropium+olodaterol+exercise training. The primary outcome is improvement in exercise capacity after 8 weeks, measured by endurance time during a shuttle walk test. The secondary outcome is improvement in physical activity, including objective accelerometer assessment and patient-reported functioning using the Functional Performance Inventory-Short Form and the novel hybrid PROactive instrument. Additionally, the influence of moderating variables (ie, factors influencing a patient's choice to be physically active) on increases in physical activity is also explored.

Ethics And Dissemination: The study has been approved by the relevant Institutional Review Boards, Independent Ethics Committee and Competent Authority according to national and international regulations. The findings of the trial will be disseminated through relevant peer-reviewed journals and international conference presentations.

Trial Registration Number: NCT02085161.
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http://dx.doi.org/10.1136/bmjopen-2015-010106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4838678PMC
April 2016

Behaviour-change intervention in a multicentre, randomised, placebo-controlled COPD study: methodological considerations and implementation.

BMJ Open 2016 Apr 4;6(4):e010109. Epub 2016 Apr 4.

Evidera, Bethesda, Maryland, USA.

Introduction: Chronic obstructive pulmonary disease is generally progressive and associated with reduced physical activity. Both pharmacological therapy and exercise training can improve exercise capacity; however, these are often not sufficient to change the amount of daily physical activity a patient undertakes. Behaviour-change self-management programmes are designed to address this, including setting motivational goals and providing social support. We present and discuss the necessary methodological considerations when integrating behaviour-change interventions into a multicentre study.

Methods And Analysis: PHYSACTO is a 12-week phase IIIb study assessing the effects on exercise capacity and physical activity of once-daily tiotropium+olodaterol 5/5 µg with exercise training, tiotropium+olodaterol 5/5 µg without exercise training, tiotropium 5 µg or placebo, with all pharmacological interventions administered via the Respimat inhaler. Patients in all intervention arms receive a behaviour-change self-management programme to provide an optimal environment for translating improvements in exercise capacity into increases in daily physical activity. To maximise the likelihood of success, special attention is given in the programme to: (1) the Site Case Manager, with careful monitoring of programme delivery; (2) the patient, incorporating patient-evaluation/programme-evaluation measures to guide the Site Case Manager in the self-management intervention; and (3) quality assurance, to help identify and correct any problems or shortcomings in programme delivery and ensure the effectiveness of any corrective steps. This paper documents the comprehensive methods used to optimise and standardise the behaviour-change self-management programme used in the study to facilitate dialogue on the inclusion of this type of programme in multicentre studies.

Ethics And Dissemination: The study has been approved by the relevant Institutional Review Boards, Independent Ethics Committee and Competent Authority according to national and international regulations. The results of this study will be disseminated through relevant, peer-reviewed journals and international conference presentations.

Trial Registration Number: NCT02085161.
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http://dx.doi.org/10.1136/bmjopen-2015-010109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4823464PMC
April 2016

Aerosolized clindamycin is superior to aerosolized dexamethasone or clindamycin-dexamethasone combination in the treatment of severe Porphyromonas gingivalis aspiration pneumonia in an experimental murine model.

Exp Lung Res 2012 Feb 8;38(1):9-18. Epub 2011 Dec 8.

Veterinary Faculty, Small Animal Clinic, University of Ljubljana, Ljubljana, Slovenia.

Adjunctive corticosteroid treatment to reduce excessive local inflammatory response in pneumonia is controversial. To study the effects of an early local adjunct dexamethasone treatment on the course of pneumonia and inflammatory/cytokine response, mice were intratracheally inoculated with live Porphyromonas gingivalis and treated with either clindamycin (C), dexamethasone (D), C+D combination, or were not treated (Pg). Six mice from each group were euthanized at 6, 24, 72, and 168 hours after inoculation. Levels of tumor necrosis factor (TNF)-α, soluble TNF-α receptors (sTNFR1 and sTNFR2), interleukin (IL)-1β, and IL-6 in the serum and lung-homogenate supernatant were determined. Lung samples were histopathologically assessed and all findings compared to those found in 24 sham-inoculated mice (phosphate-buffered saline [PBS]). Severe P. gingivalis-induced bronchopneumonia progressed from 24 hours, peaked at 72 hours, and resolved after 168 hours with changes in local and systemic cytokine levels. Clindamycin-treated mice developed only mild bronchopneumonia that resolved fast (72 hours) with an early (6-24 hours) normalization of local and systemic cytokine levels. Similar course of pneumonia and cytokine level changes were observed in mice treated with C+D, but later. Early (6-24 hours) local elevation of sTNFRs was observed in C and C+D groups of mice, whereas nontreated (Pg) mice had increased systemic sTNFRs. Severe bronchopneumonia with delayed resolution was observed in D-group mice, with an early local and systemic decrease in sTNFR1 and persistent elevation of local TNF-α. Clindamycin or a clindamycin-dexamethasone combination treatment significantly improves the course of P. gingivalis-aspiration pneumonia, but more so if clindamycin alone is used. A favorable course of pneumonia seems to be associated with an early elevation of sTNFRs and normalization of TNF-α.
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http://dx.doi.org/10.3109/01902148.2011.632063DOI Listing
February 2012

Early systemic inflammatory response in mice after a single oral gavage with live Escherichia coli is evidenced by increased TNF-alpha and nitric oxide production.

Res Vet Sci 2012 Jun 12;92(3):401-7. Epub 2011 Apr 12.

Veterinary Faculty Small Animal Clinic, University of Ljubljana, Gerbičeva 60, 1115 Ljubljana, Slovenia.

Twenty-four female BALB/c mice were orally inoculated with 10(8) CFU Escherichia coli ATCC 25922 and euthanized 2.5, 7, 13 and 25 h post-inoculation. The levels of organ nitric oxide (NO) and plasma endotoxin, TNF-alpha and nitrite/nitrate (NO(x)) were compared to those found in sham-inoculated mice, to evaluate systemic host-response to a low-level oral exposure to Gram-negative bacteria. Organ bacterial culture and immunohistochemistry for iNOS were performed on lungs, liver, kidneys and brain from all mice. Organ NO and plasma TNF-alpha levels were higher in E. coli-inoculated animals, but no differences were detected in plasma endotoxin levels, NO(x) or iNOS immunostaining for any of the animal groups. Single oral gavage with live E. coli stimulates an early systemic immune response in clinically healthy mice as evidenced by increased plasma TNF-alpha and organ NO levels, but bacteremia and endotoxemia are not related to this inflammatory response.
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http://dx.doi.org/10.1016/j.rvsc.2011.03.021DOI Listing
June 2012

Systemic use of selective iNOS inhibitor 1400W or non-selective NOS inhibitor l-NAME differently affects systemic nitric oxide formation after oral Porphyromonas gingivalis inoculation in mice.

Arch Oral Biol 2010 Jul 28;55(7):509-14. Epub 2010 Apr 28.

University of Ljubljana, Gerbiceva, Slovenia.

Objective: Nitric oxide synthase (NOS) inhibitors are reported to protect against the local tissue damage in gingivitis and periodontal disease by reducing nitroxidative stress during inflammation, but their systemic effects are not well investigated.

Design: NOS inhibitors systemic effects were investigated in a murine chronic oral inoculation model using live Porphyromonas gingivalis ATCC 33277 (0.3 ml; 10(9)cfu/ml) or sterile broth (0.3 ml). Organ nitric oxide (NO) and plasma nitrite/nitrate (NOx) were determined in mice treated with non-selective NOS inhibitor l-NAME (50mg/kg/24h i.p.) or selective iNOS inhibitor 1400W (10mg/kg/6h i.p.) for the last 5 days of the experiment. Differences between groups were evaluated by nonparametric Wilcoxon's rank-sum one-sided two-sample test and the results compared to those obtained from sham-treated (sterile broth) sham-inoculated animals (water for injection i.p./6h).

Results: Repeated ingestion of P. gingivalis resulted in generalized production of NO in organs and NOx in plasma, the levels of both typically being reduced in P. gingivalis-inoculated-1400W-treated mice, whilst the use of l-NAME was largerly ineffective, even promoting NO/NOx formation. Application of either inhibitor to sham-inoculated animals enhanced NO/NOx formation, due only in part to the repeated i.p. injections.

Conclusions: The systemic use of 1400W or l-NAME differently affects systemic nitric oxide formation in mice orally challenged with P. gingivalis, but the sequelae of such an intervention should be evaluated further.
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http://dx.doi.org/10.1016/j.archoralbio.2010.04.003DOI Listing
July 2010

Lack of soluble tumor necrosis factor alpha receptor 1 and 2 and interleukin-1beta compartmentalization in lungs of mice after a single intratracheal inoculation with live Porphyromonas gingivalis.

Exp Lung Res 2009 Sep;35(7):605-20

Veterinary Faculty, Small Animal Clinic, University of Ljubljana, Ljubljana, Slovenia.

Porphyromonas gingivalis aspiration pneumonia induces local and systemic cytokine responses, but the dynamic of the immune response following lung exposure to live P. gingivalis is poorly understood. Groups of 50 12-week-old male BALB/c mice were inoculated intratracheally with live P. gingivalis ATCC 33277 using low dose (2 x 10(5) colony-forming units [CFU]), high dose (2.9 x 10(9) CFU), or phosphate-buffered saline (PBS; sham-inoculated), and the 3 groups were sacrificed at 2, 6, 24, 72, 168 hours. Lung and serum samples were collected for tumor necrosis factor alpha (TNF-alpha), soluble TNF-alpha receptors (sTNFRs), interleukin (IL)-1beta, and IL-6 analysis and lung histology. Pneumonia, only observed in the high-dose group, was associated with an early increase in lung TNF-alpha, IL-1beta, and IL-6, whereas no significant changes were observed in lung sTNFRs. Serum sTNFRs were significantly increased in high-dose animals at all times. IL-1beta elevation occurred earlier in serum than in lungs. IL-1beta was also significantly elevated in serum from low-dose animals at 6 hours. Serum IL-6 and sTNFRs remained raised at 7 days, whereas all other measured cytokines returned to basal levels with resolution of pneumonia. Development of pneumonia is dependent on the P. gingivalis dose; however, part of the cytokine response is unique to the systemic compartment, even in animals that do not develop pneumonia.
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http://dx.doi.org/10.1080/01902140902783381DOI Listing
September 2009

Single oral inoculation with Escherichia coli (ATCC 25922) stimulates generalised production of nitric oxide in mice.

Acta Vet Hung 2009 Mar;57(1):127-38

Veterinary Faculty Small Animal Clinic, University of Ljubljana, Gerbiceva 60, 1115 Ljubljana, Slovenia.

Nitric oxide (NO) production was investigated in the lungs, thoracic aorta, heart, liver, spleen, kidneys and brain of mice inoculated orally with Escherichia coli ATCC 25922. Detection of NO was performed by electron paramagnetic resonance (EPR) using diethyldithiocarbamate (DETC) spin trap. Nitric oxide synthase (NOS) inhibitors [nonselective: L-NAME and inducible NOS (iNOS) selective: 1400W] were used to determine the source of NO. Spin-trap only and untreated mice were included as controls. Within 2.5 hours (h) of a single oral inoculation with E. coli half of the animals had increased NO levels in all investigated organs. Thereafter the signals dropped before increasing again to reach maximal median values by 25 h in all organs of all inoculated mice. The most intense response occurred in livers, followed by aorta and lungs. Early (2.5 h) inhibition of the signal was achieved using both NOS inhibitors. L-NAME was also effective at 25 h, while 1400W-treated mice had increased NO levels beyond 7 h. The generalised increase in NO production in the short and longer term indicates a host response to E. coli administered by the oral route of infection.
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http://dx.doi.org/10.1556/AVet.57.2009.1.13DOI Listing
March 2009

Molecular epidemiology of tuberculosis in Slovenia: results of a one-year (2001) nation-wide study.

Scand J Infect Dis 2003 ;35(11-12):863-8

University Clinic of Respiratory and Allergic Diseases, Golnik, Slovenia.

Slovenia is a small Central European country with a population of 1.99 million and an incidence of tuberculosis (TB) of 18.6 per 100,000 inhabitants in 2001. In a prospective nation-wide, 1-y DNA fingerprinting study, the genetic diversity of 99.7% of all Mycobacterium tuberculosis isolates obtained from Slovenian patients with culture-verified TB in 2001 were assessed using a standardized IS6110 restriction fragment length polymorphism (RFLP) method. Among 306 M. tuberculosis isolates, 228 different IS6110 RFLP patterns were found. The number of IS6110 copies varied from 2 to 16 (9.2 copies per isolate on average). Only 2 isolates (0.7%) with less than 5 IS6110 copies were identified. Clustered M. tuberculosis isolates were detected in 116 (37.9%) patients. The degree of recent transmission in the 1-y period was 25%. The clustering rate decreased with age from 46.4% (age group under 35 y) to 19.5% (age group above 65 y). A history of alcohol abuse and homelessness was found to be associated with clustering of TB cases. In conclusion, a high clustering frequency was identified among Slovenian TB patients. The study increased our understanding of important risk factors and routes of TB transmission in Slovenia.
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http://dx.doi.org/10.1080/00365540310017221DOI Listing
February 2004
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