title: Gap junction intercellular communication and cytotoxicity in normal human cells after exposure to smoke condensates from cigarettes that burn or primarily heat tobacco.
abstract: Heating tobacco, rather than burning it, reduces tobacco combustion and pyrolysis products. This study tested the hypothesis that the simplified smoke chemistry of a cigarette which primarily heats tobacco (TOB-HT) significantly reduces the potential to alter the structure or function of cellular plasma membranes relative to low "tar" 1R4F and ultra low "tar" lR5F Kentucky reference cigarettes which burn tobacco. Gap junction intercellular communication (GJIC) and lactate dehydrogenase release (LDH) were used to quantify functional and structural changes to the plasma membrane, respectively. Cigarette smoke condensate (CSC) from the mainstream smoke of TOB-HT, lR4F and 1R5F cigarettes were compared in the GJIC and LDH release assays following a 1-hr exposure in vitro. Human bronchial/tracheal epithelial cells, coronary artery endothelial cells, coronary artery smooth muscle cells, foreskin keratinocytes and the WB-344 rat liver epithelial cell line were studied. TOB-HT did not inhibit GJIC in any of the human cell types tested (P0.05) at concentrations where 1R4F and lR5F did inhibit GJIC (P<0.05). TOB-HT did not elevate LDH release (P0.05) when tested at concentrations where lR4F and lR5F did elevate LDH release (P<0.05). Our results suggest that CSC from TOB-HT cigarettes is less damaging to the structure or function of the cellular plasma membranes of a variety of human cell lines than CSC from 1R4F and 1R5F tobacco burning reference cigarettes.
authors.affiliation: Research and Development, Bowman Gray Technical Center, R.J. Reynolds Tobacco Company, Winston-Salem, NC 27102, USA.
authors.forename: S C
authors.initials: SC
authors.lastname: McKarns
authors.forename: D W
authors.initials: DW
authors.lastname: Bombick
authors.forename: M J
authors.initials: MJ
authors.lastname: Morton
authors.forename: D J
authors.initials: DJ
authors.lastname: Doolittle
mesh_terms: D000328:Adult; D001980:Bronchi / Q000166:cytology; D002450:Cell Communication / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002999:Clone Cells; D003331:Coronary Vessels / Q000166:cytology / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects; D005260:Female; D017629:Gap Junctions / Q000187:drug effects*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015603:Keratinocytes / Q000187:drug effects; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012906:Smoke / Q000009:adverse effects*
chemical_list: D012906:Smoke; D007770:L-Lactate Dehydrogenase