Preeclamptic placental stress and over expression of mitochondrial HSP70.
BACKGROUND
Evidence is accumulating that mitochondrial (Mt) oxidative stress plays a role in the pathogenesis of preeclampsia. The current study analyzes the stress levels, energy status and associated enzymatic alteration in placental mitochondria of preeclamptic (n=30) and normotensive (n=35) subjects.


METHODS
Total Mt stress was measured using dichlorofluorescin (DCFH) oxidant analysis, malondialdehyde (MDA) concentrations, protein carbonyl (PC) concentrations and measurement of nitrite (NO2(-)) and nitrate (NO3(-)). Activity of antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPx) and the glutathione redox ratio (GRR) were measured. The ATP/ADP (adenosine triphosphate/adenosine diphosphate) concentrations and respiratory chain enzyme activities were also analyzed. The expression of heat shock protein 70 (HSP70) was measured in mitochondria.


RESULTS
The DCFH oxidants, MDA, PC concentrations, and concentrations of NO2(-) and NO3(-) were significantly higher in the preeclamptic group (p<0.01) compared with the control group. The activities of SOD, GPx, GRR [glutathione (GSH)/glutathione disulfate (GSSG)] (p<0.01, p<0.001), ATP/ADP and respiratory chain enzyme activities were reduced significantly (p<0.001) in preeclamptic conditions. The placental mitochondrial HSP70 (mtHSP70) showed significant over expression in the preeclamptic group (p<0.001) compared with the control group.


CONCLUSIONS
These results provide the first line of evidence for accumulated Mt stress demonstrated by increased stress markers, decreased antioxidants and enhanced mtHSP70. The study illustrates the probable protective mechanism of mtHSP70 against the generated stress. This is primarily to combat the enzymatic and free radical mediated damage produced in preeclampsia.
Padmini
Ekambaram
E
P.G. Department of Biochemistry, Bharathi Women's College, Affiliated to University of Madras, Chennai, Tamilnadu, India. ntrfbwc@gmail.com
Lavanya
Srinivasan
S
Uthra
Venkatraman
V
D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism; D018384:Oxidative Stress; D011225:Pre-Eclampsia / Q000175:diagnosis / Q000378:metabolism*; D011247:Pregnancy; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D018840:HSP70 Heat-Shock Proteins; D009569:Nitric Oxide; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase