Isomaltitol exacerbates neutrophilia but reduces eosinophilia: new insights into the sephadex model of lung inflammation.
BACKGROUND
We have previously examined isomaltitol in an in vitro static adhesion assay and were interested in investigating whether the potentially anti-inflammatory effects observed there could be relevant in vivo. The Sephadex-induced lung inflammation model was considered a suitablemodel due to the significant changes in global inflammatory endpoints seen upon provocation with Sephadex.


METHODS
Male Sprague-Dawley rats were instilled intratracheally with Sephadex (5 mg/ml), vehicle (0.9% NaCl), isomaltitol (50 mg/ml) or a combination of isomaltitol and Sephadex. After 24 h, the lungs were weighed to measure edema and preserved for histology. Bronchoalveolar lavage fluid was used for analysis of tumor necrosis factor, cysteinyl leukotrienes, and differential and total leukocyte counts.


RESULTS
Differential counts showed that isomaltitol increased the neutrophil component while decreasing the eosinophilia, thus asserting a modulatory role on the usually eosinophil-dominated Sephadex-induced cell profile. Isomaltitol alone also increased edema and cysteinyl leukotrienes, and generally aggravated total inflammation in combination with Sephadex. The mechanisms were not investigated in this study, but effects could relate to a combination of isomaltitol's osmotic and structure-specific properties.


CONCLUSIONS
Our results show that isomaltitol can modulate the inflammatory response induced by Sephadex instillation in addition to having proinflammatory effects on its own, and may therefore provide new insights into the mechanisms of this widely used animal model. Sugar alcohols similar to isomaltitol have already been used to aid mucus clearance in cystic fibrosis patients, and it is possible that isomaltitol could also be used for this purpose.
Department of Clinical and Experimental Medicine, Division of Cell Biology, Linköping University, Linköping, Sweden. chaev@liu.se
Chamilly
C
Evaldsson
Ingvar
I
Rydén
Srinivas
S
Uppugunduri
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology / Q000276:immunology; D003911:Dextrans; D004195:Disease Models, Animal; D004802:Eosinophilia / Q000139:chemically induced / Q000209:etiology / Q000276:immunology*; D004804:Eosinophils / Q000187:drug effects; D007509:Irritants; D008297:Male; D009504:Neutrophils / Q000187:drug effects*; D011014:Pneumonia / Q000139:chemically induced / Q000276:immunology* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013402:Sugar Alcohols / Q000494:pharmacology*
D000893:Anti-Inflammatory Agents; D003911:Dextrans; D007509:Irritants; D013402:Sugar Alcohols; C025614:sephadex; C008187:isomaltitol