Glucose & Pulmonary Infection Group

Aims of Group

1. To investigate mechanisms underlying pulmonary infection in people with diabetes mellitus or stress hyperglycaemia.
2. To identify how lung secretions are normally kept free of glucose

Background

Morbidity and mortality from pulmonary infection is greater in people with diabetes than in those with normal blood glucose. This is a particular problem in people with pre-existing lung disease (eg COPD and cystic fibrosis) and may be a factor in the development of nosocomial infections in patients with acute stress hyperglycaemia.

Normal Glucose Transport in the Lung

Glucose is not normally present in human airway secretions. We have performed hyperglycaemic clamp studies in healthy volunteers and shown that glucose does diffuse across the respiratory epithelium when blood glucose is raised. We estimate a threshold of ~8mM. Furthermore glucose rapidly disappears from the airway when the blood glucose falls suggesting the presence of glucose transporters within the respiratory epithelium.

Glucose Transporters in the Lung

In human airway epithelium we have used RT-PCR to detect mRNA for the glucose transporters SGLT-1, GLUT-1 and GLUT-2.

Airway Glucose and Pulmonary Infection

The appearance of glucose within airway secretions of patients intubated on our ITU was significantly associated with the presence of methicillin resistant Staphylococcus aureus (MRSA) from the secretions. In addition hyperglycaemic patients with COPD have higher rates of MRSA in sputum, increased mortality and longer hospital stays than their normoglycaemic counterparts.

Funding