Nanotoxicity - The Nanobiotechnology - page 611

Nanoparticles

Oxidative stress

Depletion of anti-
oxidants

Lipid peroxidation

Activate MAPK/NF-κB or other redox
sensitive signal transduction pathways

Expression of inflammatory factors

Inflammation response of respiratory
and cardiovascular system

Figure 27.6
Hypothetical.molecular.mechanism.of.inlammation.triggered.by.nanoparticles.

explained. by. translocation. of. nanoparticles. (or. ultraine. particles). from. the. respiratory.
epithelium.toward.circulation.and.subsequent.toxicity.to.vascular.endothelium;.alteration.
of. blood. coagulation;. and. triggering. of. autonomic. nervous. system. relexes. eventually.
altering. the. cardiac. frequency. and. function.. Further. experimental. results. indicate. that.
the. adverse. cardiovascular. events. mainly. come. from. inlammation,. which. is. caused.
by. nanoparticles. accumulation.. Recent. direct. evidence. comes. from. an. isolated. beating.
heart.model.system..This.model.enables.observation.and.analysis.of.electrophysiological.
parameters.over.a.minimal.time.period.of.4.h.without.inluence.by.systemic.effects.and.
allows. the. determination. of. the. stimulated. release. of. substances. under. the. inluence. of.
nanoparticles..It.has.been.found.that.a.signiicant.dose.and.material.dependence.causes.
an. increase. in. heart. rate. accompanied. by. arrhythmia,. elevation. of. ST. segment,. and.
atrioventricular. block. evoked. by. engineered. nanoparticles. made. of. lame. soot. (Printex.
90),.spark.discharge.generated.soot,.anatas.TiO 2 ,.and.SiO 2 ..However,.lame.derived.SiO 2 .
(aerosil).and.monodispersed.polystyrene.lattices.exhibited.no.effects..The.increase.in.heart.
rate.could.be.assigned.to.a.catecholamine.release.from.adrenergic.nerve.endings.within.
the.heart.(Stampl.et.al..2011)..Atherosclerosis.and.its.attendant.morbidity.and.mortality.
remain.a.big.threat.to.global.health..The.importance.of.oxidant.stress.in.atherothrombotic.
cardiovascular. disease. is. demonstrated. by. the. observation. that. increased. markers. of.
oxidant. stress. have. been. shown. to. predict. coronary. heart. disease.. F 2 -isoprostanes. are.
lipid. peroxidation. products. of. arachidonic. acid. in. the. cell. membrane. and. are. reliable.
biomarkers. for.oxidative. stress.and.cell. membrane.damage.. The.levels. of.F 2 -isoprostane.