Interpretation
Martinique is an insular region of France located in the Lesser Antilles
of the West Indies in the eastern Caribbean Sea. Coastlines of
Martinique have witnessed successive and massive waves of sargassum
seaweed invasions over the last two decades 12-14.
Ecological prediction models indicate that these massive strandings are
likely to repeat leading to economic, social and public health concerns34. Due to marine currents and maritime trade winds,
strandings of sargassum seaweed only impacted the Atlantic coastlines of
Martinique. Specific areas are particularly impacted by sargassum
strandings, which motivated the installation of ground gas sensors to
monitor H2S released from anaerobic degradation of
sargassum strandings. Since 2016, this network has allowed to evaluate
exposure of the population, to inform the local population and
authorities about air quality on a daily basis, as well as to launch
population evacuation warnings when required. In our study, we used the
living place and/or workplace by define H2S exposure13. We observed that less than a half of pregnant
women had a job, which was located in the borough of residency in more
than ninety percent of cases (data no shown). Overall, qualitative
classification of H2S exposure of pregnant women was
reasonable well defined.
The increased risk of preeclampsia that we found in H2S
exposure pregnant women seem to conflict the large body of literature
showing protective action of H2S in cardiovascular
pathologies such as hypertension, atherosclerosis and pulmonary
hypertension 30-32. Proposed mechanisms of
H2S-induced vascular beneficial effects include
anti-oxidative action, preservation of mitochondrial function, reduction
of apoptosis, anti-inflammatory responses, angiogenic action, regulation
of ion channel, and increasing the production of NO9,10, 30-32. In line, few epidemiological studies have
previously suggested a protective role of H2S in
atherosclerosis onset and development 20,23,24,27. As
a different paradigm, H2S have several mechanisms of
toxicity, including inhibition of cytochrome c oxidase activity, protein
kinases (JNK and Erk) activation and cellular damage from reactive
oxygen species, which participate to vascular structure and function
impairment 30-32. Although the primary action of
H2S on the vasculature is relaxation,
H2S can exert vasoconstriction under some conditions9. Indeed, H2S exerts biphasic effect
on vascular tissue and produces vasoconstriction at low concentrations,
while inducing vasorelaxation at higher concentrations.
H2S-induced vasoconstriction has been attributed to NO
quenching or inactivation, inhibition of endothelial cell NO synthase,
and NO-independent mechanisms which include lowering cyclic adenosine
monophosphate (cAMP) levels in vascular smooth muscle cells9,11,31,33. Such impact of H2S on the
vasculature may explain the deleterious cardiovascular effects of
H2S exposure observed in geothermal areas and industrial
regions. For example, a significant increase of incidence for diseases
of circulatory system and of mortality for hypertensive disease was
observed in the geothermal area and industrial regions20,26,27. Overall, increased risk of preeclampsia that
we found in H2S-exposed pregnant women is consistent
with these previous studies.