Cockroach extract antigen increases bronchial airway epithelial permeability.
BACKGROUND
The bronchial epithelial cells of airways are subject to recurrent environmental injury throughout the life of an individual. Recently, a high incidence of asthma has been reported in inner-city children. The increased incidence of asthma in inner-city children is thought to be caused, in part, by frequent exposure to allergens of the common household pest the cockroach.


OBJECTIVE
We sought to investigate whether cockroach extract antigen (CrAg) induces vascular permeability factor, also known as vascular endothelial growth factor (VEGF), and whether it increases permeability in bronchial airway epithelial cells (BAECs).


METHODS
We estimated CrAg-induced VEGF release in BAECs by using an ELISA and VEGF mRNA expression by using an RT-PCR reaction. The influence of CrAg on BAEC barrier function was estimated by measuring electrical resistance with an electric cell substrate impedance-sensing system.


RESULTS
Our results demonstrate that CrAg induces VEGF release in BAECs in a time-dependent manner. The VEGF induction was also confirmed by means of VEGF mRNA expression in CrAg-stimulated BAECs. CrAg decreased electrical resistance across BAEC monolayers. The maximum decrease in electrical resistance was noticed 6 hours after activation and reached a plateau thereafter. Neutralizing antibodies to VEGF significantly inhibited the decrease in BAEC electrical resistance caused by CrAg.


CONCLUSIONS
These data suggest that CrAg induces VEGF release in BAECs and alters bronchial airway permeability.
Antony
Ajay B
AB
Division of Pulmonary Allergy Critical Care and Occupational Medicine, Department of Medicine, Veterans Affairs Medical Center, 1481 West 10th Street, 111P, Indianapolis, IN 46202, USA.
Tepper
Robert S
RS
Mohammed
Kamal A
KA
D000818:Animals; D000941:Antigens / Q000737:chemistry / Q000494:pharmacology*; D016282:Aspartic Acid Endopeptidases / Q000032:analysis; D001980:Bronchi / Q000378:metabolism* / Q000502:physiology; D002478:Cells, Cultured; D003058:Cockroaches / Q000737:chemistry*; D017097:Electric Impedance; D016228:Endothelial Growth Factors / Q000235:genetics / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism / Q000502:physiology; D006801:Humans; D008222:Lymphokines / Q000235:genetics / Q000378:metabolism; D010539:Permeability / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D012697:Serine Endopeptidases / Q000032:analysis; D014020:Tissue Extracts / Q000737:chemistry / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D000941:Antigens; D016228:Endothelial Growth Factors; D008222:Lymphokines; D012333:RNA, Messenger; D014020:Tissue Extracts; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D012697:Serine Endopeptidases; D016282:Aspartic Acid Endopeptidases