Is there an oxidative cost of acute stress? Characterization, implication of glucocorticoids and modulation by prior stress experience.

Acute rises in glucocorticoid hormones allow individuals to adaptively respond to environmental challenges but may also have negative consequences, including oxidative stress. While the effects of chronic glucocorticoid exposure on oxidative stress have been well characterized, those of acute stress or glucocorticoid exposure have mostly been overlooked. We examined the relationship between acute stress exposure, glucocorticoids and oxidative stress in Japanese quail (Coturnix japonica). We (i) characterized the pattern of oxidative stress during an acute stressor in two phenotypically distinct breeds; (ii) determined whether corticosterone ingestion, in the absence of acute stress, increased oxidative stress, which we call glucocorticoid-induced oxidative stress (GiOS); and (iii) explored how prior experience to stressful events affected GiOS. Both breeds exhibited an increase in oxidative stress in response to an acute stressor. Importantly, in the absence of acute stress, ingesting corticosterone caused an acute rise in plasma corticosterone and oxidative stress. Lastly, birds exposed to no previous acute stress or numerous stressful events had high levels of GiOS in response to acute stress, while birds with moderate prior exposure did not. Together, these findings suggest that an acute stress response results in GiOS, but prior experience to stressors may modulate that oxidative cost.

The red cell distribution width as a prognostic indicator in idiopathic pulmonary fibrosis.

BACKGROUND: The course of idiopathic pulmonary fibrosis (IPF) is characterized by variable patterns of disease progression. The red cell distribution width (RDW) is a parameter that is routinely reported with all CBC counts. We sought to test the prognostic usefulness of this parameter in a well-defined cohort of patients with IPF. METHODS: CBCs, demographics, and pulmonary function data from patients with IPF evaluated between January 1997 and June 2011 were collated. Patient outcomes were ascertained from the program's database and the Social Security Death Index. RESULTS: There were 319 patients with IPF evaluated in whom baseline CBCs were available. The range in the RDW was 11.9 to 21.9 (median 14.1). There were 228 subjects with RDW values ≤ 15 (normal) and 91 patients with RDW values > 15. Patients with normal RDW values had a median survival of 43.1 months compared with 16.3 months for those whose RDW was > 15 (P = .001). There were 198 patients with available serial RDW data. Those patients who had a change in the RDW of less or greater than +0.010/mo had median survivals of 43.0 and 23.9 months, respectively (P = .0246). CONCLUSIONS: The RDW is a readily available laboratory test result that may provide important, independent prognostic information at baseline and follow-up in patients with IPF. Further studies are warranted to validate this as a biomarker for IPF outcomes, as well as to define the biologic basis for this association.