In vitro and in vivo uptake study of Escherichia coli Nissle 1917 bacterial ghosts: cell-based delivery system to target ocular surface diseases.
OBJECTIVE
For the successful topical administration of drugs or vaccines to treat ocular surface diseases, efficient and well-tolerated delivery systems/carriers for conjunctival delivery are crucial in the development of new treatment strategies. The present study investigated the efficiency of internalization of bacterial ghosts (BGs) produced from probiotic Escherichia coli Nissle 1917 (EcN) by human conjunctival epithelial (HCjE) cell line, the EcN BGs cytotoxicity for HCjE cells, and in vivo uptake of EcN BGs by conjunctival guinea pig epithelial cells.


METHODS
The uptake of EcN BGs by HCjE cells was analyzed by laser scanning microscopy and flow cytometry. Immunohistochemistry was used to localize the EcN BGs in the guinea pig conjunctival tissue. Cytotoxicity of EcN BGs on HCjE cells was evaluated by measurement of LDH.


RESULTS
Laser scanning microscopy and flow cytometry revealed that EcN BGs internalization by HCjE cells was time- and dose dependent. No cytotoxic effect on HCjE cells was observed after EcN BGs inoculation for 30 and 120 minutes, as well as 24 hours. In addition, the uptake of EcN BGs was detected in the conjunctival cells after in vivo administration of EcN BGs into the eye of the guinea pig.


CONCLUSIONS
The findings that EcN BGs are nontoxic and effectively internalized in vitro by human and in vivo by guinea pig conjunctival cells comprise an important contribution to the future use of BGs as a system for conjunctival delivery of drugs and vaccines, either to treat or prevent ocular surface diseases.
Medical University Vienna, OCUVAC-Laura Bassi Centres of Expertise, Institute of Specific Prophylaxis and Tropical Medicine, Centre of Pathophysiology, Infectiology and Immunology, Vienna, Austria.
Elisabeth
E
Stein
Aleksandra
A
Inic-Kanada
Sandra
S
Belij
Jacqueline
J
Montanaro
Nora
N
Bintner
Simone
S
Schlacher
Ulrike Beate
UB
Mayr
Werner
W
Lubitz
Marijana
M
Stojanovic
Hristo
H
Najdenski
Talin
T
Barisani-Asenbauer
D000818:Animals; D002460:Cell Line; D003228:Conjunctiva / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D003229:Conjunctival Diseases / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D016503:Drug Delivery Systems; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004926:Escherichia coli; D005434:Flow Cytometry; D006168:Guinea Pigs; D006801:Humans; D018613:Microscopy, Confocal; D019936:Probiotics / Q000008:administration & dosage / Q000493:pharmacokinetics*
bacterial ghosts; drug delivery; guinea pig; human conjunctival cell line; ocular surface