> Is there a direct link between IBD and Dioxins?
Developmental dental toxicity of dioxin and related compounds--a
review.
Non-halogenated polycyclic aromatic hydrocarbons (PAHs) and
halogenated aromatic hydrocarbons such as polychlorinated dibenzo-p-
dioxins and dibenzofurans (PCDD/Fs, or dioxins), and polychlorinated
biphenyls (PCBs) are wide-spread environmental pollutants that have
unequivocal adverse effects on different species, including humans.
Accidental exposure of children to high amounts of PCDD/Fs has been
found to be associated with developmental enamel defects and missing
permanent teeth. An association between dioxin exposure via mother's
milk and developmental mineralisation defects in permanent first
molars was also found in otherwise healthy Finnish children born in
the late 1980s but not in those born in the late 1990s. Results of
experimental animal studies in vivo and in vitro are compatible with
findings in human teeth. In addition to the dose, dental effects of
the most toxic dioxin congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin
(TCDD), essentially depend on the stage of tooth development at the
time of exposure. Accordingly, TCDD arrests early rat and mouse molar
tooth development and in more advanced teeth it interferes with
mineralisation of enamel and dentine and arrests root development.
Expression of the specific dioxin receptor (AhR) in dental cells at
TCDD-sensitive stages of tooth development suggests that the dental,
like other developmental effects of TCDD, are mediated by the AhR.
Early effects also depend on the epidermal growth factor receptor and
involve enhanced apoptosis. The lowest TCDD dose (30ng/kg) causing
adverse dental effects in rats has been estimated to result in
maternal tissue levels approaching the high end of human background
range and human milk PCDD/F levels that were associated with enamel
defects in children. However, because of the uniform and clear decline
in background dioxin and PCB levels in mother's milk during the last
twenty years, dioxins are currently likely to be of small or no
account as regards developmental dental defects in children. Even so,
this is not the case after heavy exposure and little is known about
the possible synergistic effects of these toxicants with other
chemicals interfering with tooth development. PMID: 17243464
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