Chronic Obstructive Pulmonary Disease (COPD)

The World Health Organisation (WHO) predicts that COPD will become the third leading cause of death worldwide by 2030.

A progressive-obstructive disease that is not completely reversible and is predominantly caused by smoking. It is characterised by intermittent flare-ups that commonly lead to bacterial infections. Emphysema and chronic bronchitis are both features of COPD. 

Facts on COPD

• 80 million people have moderate–to–severe COPD worldwide
• The annual cost of COPD is estimated to be €38.8 billion in Europe

Emphysema

A result of terminal bronchiole and distal airway tissue destruction. Patients with emphysema will have a hyper-inflated chest and respiration will be inadequate.

Chronic Bronchitis

Chronic hyper-secretion of mucus, associated with proliferation of mucus producing cells along the epithelium of the respiratory tract, this leads to obstruction.

Acute exacerbation COPD - AECOPD 

An AECOPD episode refers to a short period when COPD symptoms worsen dramatically. 

We have multiple projects focused on investigating the bacterial composition in COPD with respect to air pollution; similarly to cigarette smoke, air pollution can contribute to the onset and acute exacerbations of COPD. We know that particle matter (PM), an air pollutant, is a particular contributor and part of our work aims to increase an understanding of this issue.

Microbiology and COPD

The microbiome of the respiratory tract can play an important role in the identity of COPD.

The microbiome refers to the microbial communities which colonise various areas of the human body. At the University of Leicester we are discovering the importance of these communities in our health and wellbeing, and we take interest in the communities in the respiratory tract and on the skin.

More specifically Professor Mike Barer and Professor Chris Brightling are studying the microbiome profiles of individuals who are suffering from two major respiratory diseases, chronic obstructive pulmonary disease (COPD) and asthma. These studies are focused on identifying efficacious therapeutics and determining whether microbiome composition leads to biologic exacerbation clusters in these diseases. 

The microbiome of the respiratory tract is dominated by two major bacterial genera, Bacteroidetes and Firmicutes. An increased number of bacterial species are associated with stable COPD. During AECOPD the lung microbiome shifts so that an abundance of proteobacteria are present. In fact, 40-60% of AECOPD patients are colonised by Haemophilus influenzae, Moraxella catarrhalis and/or Streptococcus pneumoniae. AECOPD episodes worsen the respiratory function and disease progression consequently decreasing the quality of life for patients. 

• Haemophilus influenzae (NTHi -non- typeable Haemophilus influenzae)
• Streptococcus pneumoniae
• Moraxella catarrhalis  

Streptococcus pneumoniae

S. pneumoniae is the most common respiratory pathogen in the United Kingdom and a frequent cause of mortality worldwide. Often S. pneumoniae infection is preceded by asymptomatic colonisation that has the potential to lead to three acute infections; sepsis, meningitis and pneumonia. The role of this bacterial species in COPD has not of yet been fully elucidated and is under appreciated. This is an area where LeMID researchers are collaboratively working towards impacting on disease outcome and progression. 

More on Streptococcus pneumoniae

Moraxella catarrhalis 

Strains of M. catarrhalis are less common than H. influenzae and Streptococcus in COPD patients, nevertheless the number of strains of this species is diverse among COPD patients. M. catarrhalis is an opportunistic, gram-negative aerobic, bacteria. This bacterial species is found in the normal flora of the nasopharynx of 1-5% of healthy adults and at higher rates in toddlers. M. catarrhalis is one of three most common pathogens associated with AECOPD.

Sputum M. catarrhalis strains exhibit diversity within and between COPD subjects, Brightling et al. 

Haemophilus influenzae

H. influenzae is a frequent commensal of the nasopharynx in healthy children and to a lesser extent in adult. This bacterial species is also, however, an opportunistic pathogen causing ear infections (otitis media), meningitis (serogroup b strains only) and lower respiratory tract (LRT) infections. Multiple mechanisms have evolved in this organisms that facilitate evasion of the host-immune system. These mechanisms, combined with immunosuppression, can lead to the bacteria residing in the lower respiratory tract (LRT). H. influenzae colonisation of the LRT will lead to inflammation and exacerbate COPD symptoms.

COPD and the bigger picture

Professor Chris Brightling, a Wellcome Trust Senior Research Fellow at the University of Leicester and an honorary consultant, has been a major contributor to the AirPROM project that began in 2011. AirPROM (Airway Disease Predicting Outcomes through Patient Specific Computational Modelling) brings together experts and current research to build a multi-scale computational model of the lung as a new way of characterising asthma and COPD.

In a 2017 press release Professor Brightling said: