Airway constrictor response to cotton bract extracts in the absence of endotoxin.

Abstract

Crude and purified aqueous extracts of cotton bracts shown to cause airway constriction in naive subjects were assayed for endotoxin content. Pulmonary function measured by flow changes on partial expiratory flow volume curves was used to assess airway responses to the bract extracts after their inhalation by a panel of volunteers. These responses are similar to the acute responses experienced by cotton textile workers. Crude aqueous extracts from various bracts harvested before and after senescence of the cotton plant displayed endotoxin concentrations ranging widely from 0-086 to 50 ig/ml. No correlation was found between these differences in endotoxin content and the severity of the airway constrictor response. Purifying the bract extract by a series of procedures that included precipitation of polymeric material by addition of methanol and chromatography on an anion exchange column of DEAE-Sephacel resulted in the elimination of almost all the endotoxin. The partially purified extract contained less than 1 ng/ml of endotoxin. The panel of volunteers responded to this purified bract extract, however, with a decrease in pulmonary function which was more than 60% of that seen with the crude extract of bracts. It is concluded that aqueous extracts of cotton bract contain an agent(s) other than endotoxin that causes acute airway constriction in people.Cotton dust and cotton bract contain endotoxin, the amount of which varies widely depending, at least in part, on cotton quality, growing conditions, and growing location.' Pernis et al suggested that byssinosis, the specific lung disease of cotton textile workers, may be due to endotoxins produced by the Gram negative bacteria normally found on cotton bracts.2 The bacterial content of the cotton bales being processed in one experiment3 and airborne microorganisms in another4 correlated with the prevalence of byssinotic symptoms. In the latter study, however, airborne endotoxin did not correlate with symptoms. In recent studies Diem et al found that decreases in pulmonary function over the work shift correlated with airborne dust concentration, not with bacterial or endotoxin concentrations.' By contrast, Olenchock et al found in an experimental card room environment that FEV, decreases correlated with endotoxin content in the air significantly better than with airborne dust levels,6 and Rylander et al also found a dose response relation between airborne endotoxin and decreases in FEV, although the latter cautioned that the endotoxin levels may be only an

Long-term respiratory health effects in textile workers

“…Another component in cotton dust may cause the acute bronchoconstrictive response to cotton dust; a study in healthy human volunteers did not demonstrate a dose-response relationship between the endotoxin content of cotton bract extracts and acute drops in FEV 1 [45]. …”

Gender differences in the effect of occupational endotoxin exposure on impaired lung function and death: the Shanghai Textile Worker Study

“…There remains debate about whether chronic exposure to the endotoxin component of organic dust ultimately leads to abnormal lung function12 in a healthy working population with often better than predicted lung function. The effects of cotton dust have been best studied in the context of respiratory effects, where an asthma-like syndrome called byssinosis was first described,13 with later studies demonstrating an accelerated decline in lung function 14.…”

Pulmonary Reactions to Organic Dust Exposures: Development of an Animal Model

“…An etiologic agent associated with organic ckist, in addition to endotoxin, is supported by evidence that grain dust extracts remained chemotactic to neutrophils even after removal of endotoxin (98). Similarly, cotton bract extracts, purified by column chromatography to remove endotoxin, still caused bronchoconstriction in human volunteers (99). At relatively high doses, this cotton bract extract caused a significant increase in breathing rate and cellular inflammation in guinea pigs (100); however, it should be noted that this cellular and breathing rate response was smaller than that seen with cotton dust exposure.…”