Steroid Resistance During COPD Exacerbations With Respiratory Failure

Chronic obstructive pulmonary disease (COPD) is a cigarette smoke-induced disease of the lungs that affects millions of people in the United States and worldwide. COPD is the 3rd leading cause of death, making it one our most important public health problems. Perhaps most importantly, COPD confines many people to their homes, tethers them to oxygen lines, and destroys their independence. Like many diseases of chronic inflammation, the course of COPD is marred by intermittent disease flares that need more intensive treatment. In COPD, disease flares are called acute exacerbations of COPD (AECOPDs). AECOPDs are characterized by increased shortness of breath, wheezing or cough that leads to urgent, and sometimes emergent, treatment with inhaled bronchodilators, antibiotics and steroids. AECOPDs can be devastating to many because they worsen quality of life and lung function, frequently lead to hospitalization, and increase the risk of death. For instance, the death rate can reach 25-30% when COPD patients are admitted to the intensive care unit with respiratory failure (i.e. needing ventilator support). Accordingly, our research is focused on improving outcomes in the sickest patients admitted to the hospital with an AECOPD. Oral or intravenous steroids (glucocorticoids) have been the mainstay of treatment for over 40 years, but virtually no research has been done to determine the optimal therapy for the sickest patients who are admitted to the intensive care unit. Results from the few clinical studies suggest that steroid resistance is increased in these critically-ill patients and that many physicians under- or over-dose steroids. For example, patients hospitalized with an AECOPD (without respiratory failure) are effectively treated with steroids (such as prednisone) dosed as low as 40mg/day. In contrast, two recent clinical studies showed that \~80mg/day of prednisone was ineffective for AECOPD patients hospitalized with respiratory failure (those who require ventilatory support), while in a second study \~160mg/day of methylprednisolone improved outcomes. The investigators recent epidemiologic study showed that 66% of patients admitted with an AECOPD and respiratory failure between 2003-2008 were treated with \>240mg/day of methylprednisolone, a dose that increases steroid-related side effects. The investigators hypothesize that there is a stepwise increase in steroid resistance with COPD\<AECOPD\<AECOPD with respiratory failure. A newly launched team of investigators is focused on establishing the presence of steroid resistance, defining the cause(s), devising new treatments to combat this problem and optimizing therapy for these vulnerable patients. Steroids suppress inflammation by inducing anti-inflammatory genes, such as the dual-specificity phosphatase (DUSP) family - including DUSP1. DUSP1 inhibits inflammatory cytokines by removing phosphates from p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinases, which turns them off. Preliminary data show that DUSP1 is decreased in alveolar macrophages from COPD patients, suggesting the central hypothesis that steroid resistance is increased in AECOPDs with respiratory failure due to impaired glucocorticoid-mediated induction of DUSP1. To address this hypothesis, the investigators will inject 23 AECOPD patients with respiratory failure and 23 matched stable COPD subjects with 60mg of methylprednisolone to: 1) determine the presence of corticosteroid resistance in AECOPDs, 2) determine the role of DUSP1, and 3) examine alternative mechanisms driving steroid resistance. The goal of The AECOPD Resistance Study is to identify targets associated with steroid resistance in AECOPDs with respiratory failure to pave the way for new treatments based upon novel mechanisms.