Enrique Diaz-Guzman

Epidemiology and Prevalence of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) represents one of the main causes of morbidity and mortality worldwide. According to the World Health Organization, approximately 3 million people in the world die as a consequence of COPD every year. Tobacco use remains the main factor associated with development of disease in the industrialized world, but other risk factors are important and preventable causes of COPD, particularly in the developing world. The purpose of this review is to summarize the literature on the subject and to provide an update of the most recent advances in the field.

COPD and gender differences: an update.

Chronic obstructive lung disease (COPD) is one of the most prevalent health conditions, and a major cause of morbidity and mortality around the globe. Once thought of primarily as a disease of men, COPD is now known to be increasingly prevalent among women. Although increasing tobacco consumption among women during the past several decades might explain some of this increase, the relationship may be more complex, including factors such as differential susceptibility to tobacco, anatomic and hormonal differences, behavioral differences, and differences in response to available therapeutic modalities. Moreover, women with COPD may present differently, may have a different pattern of comorbidities, and may have a better survival after acute exacerbations. Care providers continue to have a gender bias that may affect both diagnosis and treatment. Future work should focus on factors that lead to gender differences in COPD as well as gender-specific treatment strategies.

Characteristics of patients with pulmonary venoocclusive disease awaiting transplantation.

RATIONALE Pulmonary venoocclusive disease (PVOD) is an uncommon cause of pulmonary arterial hypertension (PAH). However, unlike PAH, treatment options for PVOD are usually quite limited. The impact of the lung allocation score on access to transplantation for patients with PVOD and the clinical course of these patients have not been well-described. OBJECTIVES To examine the association between the diagnosis of PVOD and lung transplantation for patients on the transplant waiting list. METHODS Patients with a diagnosis of PVOD and PAH registered on the United Network for Organ Sharing wait list for transplantation from May 4, 2005 to May 3, 2013 were included. Lung transplantation was the primary outcome measure. Multivariable analyses were performed to determine the odds of dying or receiving a lung transplant after listing. Survival was compared using Kaplan-Meier and competing risks methods. RESULTS Of 12,251 patients listed for lung transplantation, 49 with PVOD and 647 with PAH were identified. There were no significant differences in the lung allocation score between patients with PVOD and PAH at listing, transplant, or wait list removal for death/too sick for transplant. By 6 months, 22.6% of patients with PVOD had been removed from the wait list due to death, compared with 11.0% of patients with PAH (Chi-square P = 0.03). Patients with PVOD who died or were considered too sick for transplant were removed from the waiting list sooner after listing (22 vs. 105 d, P = 0.08). There was no difference in the proportion of patients with PVOD and PAH transplanted (50.0 vs. 47.6%, P = 0.60). CONCLUSIONS In the lung allocation score era, patients with PVOD may be at higher risk for death while on the transplant waiting list. After wait list registration, close monitoring for disease progression is advised.

Distal airway microbiome is associated with immunoregulatory myeloid cell responses in lung transplant recipients

BACKGROUND Long-term survival of lung transplant recipients (LTRs) is limited by the occurrence of bronchiolitis obliterans syndrome (BOS). Recent evidence suggests a role for microbiome alterations in the occurrence of BOS, although the precise mechanisms are unclear. In this study we evaluated the relationship between the airway microbiome and distinct subsets of immunoregulatory myeloid-derived suppressor cells (MDSCs) in LTRs. METHODS Bronchoalveolar lavage (BAL) and simultaneous oral wash and nasal swab samples were collected from adult LTRs. Microbial genomic DNA was isolated, 16S rRNA genes amplified using V4 primers, and polymerase chain reaction (PCR) products sequenced and analyzed. BAL MDSC subsets were enumerated using flow cytometry. RESULTS The oral microbiome signature differs from that of the nasal, proximal and distal airway microbiomes, whereas the nasal microbiome is closer to the airway microbiome. Proximal and distal airway microbiome signatures of individual subjects are distinct. We identified phenotypic subsets of MDSCs in BAL, with a higher proportion of immunosuppressive MDSCs in the proximal airways, in contrast to a preponderance of pro-inflammatory MDSCs in distal airways. Relative abundance of distinct bacterial phyla in proximal and distal airways correlated with particular airway MDSCs. Expression of CCAAT/enhancer binding protein (C/EBP)-homologous protein (CHOP), an endoplasmic (ER) stress sensor, was increased in immunosuppressive MDSCs when compared with pro-inflammatory MDSCs. CONCLUSIONS The nasal microbiome closely resembles the microbiome of the proximal and distal airways in LTRs. The association of distinct microbial communities with airway MDSCs suggests a functional relationship between the local microbiome and MDSC phenotype, which may contribute to the pathogenesis of BOS.

Prolonged Extracorporeal Membrane Oxygenation Use as a Bridge to Lung Transplantation: It Is Time for a National Registry

Correspondence Although we cited reference 30 (cited here as reference 2) under Subjects in the Materials and Methods section, it might have been better to also cite it under Estimation of Sleep Duration in the Materials and Methods section. Altogether, we believed that the use of the actigraph along with the diary for the purpose of the two studies would be superior to the use of only a sleep diary. As Dr Kawada mentioned, sleep duration was a key factor in this study, 1 and the participants wore the actigraph for 7 days so we could measure the mean daily sleep duration. An actigraph (Actiwatch AW-Light; Mini Mitter or Koninklijke Philips Electronics NV) has been used in many reports. We believed that the use of the actigraph as described here was suitable for this study. We appreciate the comments of Dr Kawada. They enabled us to provide details of our method for calculating sleep duration that were only briefl y provided in our article. 1

Unexplained hemolysis in patients undergoing ECMO: beware of hypertriglyceridemia

Hemolysis is a common complication of extracorporeal membrane oxygenation (ECMO) support and is associated with increased mortality. Frequent monitoring of markers of hemolysis is performed at ECMO centers. We report two cases of spurious hemolysis caused by hypertriglyceridemia in patients undergoing ECMO support. Critically ill patients, including those receiving ECMO, may be at risk of developing medication-induced hypertriglyceridemia. The interference of lipids with the measurement of plasma free hemoglobin, a marker of hemolysis, should be recognized. Our cases highlight the importance of investigating hypertriglyceridemia as part of the assessment of unexplained hemolysis in patients supported with ECMO.