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Nasal PMN response to repeated challenge with endotoxin in healthy volunteers**
Citation:
Doreswamy, V., N. Alexis, H. Zhou, AND D. Peden. Nasal PMN response to repeated challenge with endotoxin in healthy volunteers**. INHALATION TOXICOLOGY. Informa Healthcare USA, New York, NY, 23(3):142-147, (2011).
Impact/Purpose:
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Description:
Abstract Rationale: We have employed nasal challenge with Iipopolysaccharid (lPS) followed by nasal lavage (NU to experimentally induce and examine upper airway inflammation in human volunteers.It is unclear however whether adaptation within individuals occurs following repeated nasal challenge. This was a pilot study to determine if repeated nasal LPS challenge yields attenuation of markers of inflammation (primarily neutrophil response) in the NL fluid of healthy humans. Methods: We employed a 3-day nasal LPS challenge protocol with NL using a·"split nose" design. The controland LPS nares received two consecutive day saline (O.9% saline/day) and LPS(2ug LPS/day) challenges, respectively followed by an LPS (2 ug/day) challenge to each nare on Day 3. NL was performed Immediately pre Day 1 challenges and 6-h post nasal LPS challenges on both Days 1 and 3. Markers of inflammation(PMlI/s/mg,cytokines)were assessed in NL and the inflammatory response to LPS(measured as the difference between pre and post challenge)was evaluated in both nares on Day 3 and compared to Day 1. Results: Significant (p <0.05) blunting of the LPS-induced polymorphonuclear leukocyte (PMN)response was observed in the nare that received repeated LPS chalienges as compared to the control nare(67.60±22.39vs.157.8±76.04 PMN/mg) and initial LPS challenge on Day 1 (121 ±32 PMN/mg). decreased soluble CD14 and significantly decreased interleukin-8 were also found In the repeat LPS-treated nare. ln the LPS-treated nare, the blunted PMN response on Day3 correlated well with the observed PMN response on Day1 (r=0.58, p = 0.02). Conclusions: We show attenuation of PMN response to repeated LPS in the nasal airways in healthy humans. Effect of repeat endotoxin exposure prior to allergen delivery on local airway inflammation in both healthy and atopic subjects can be studied.