F. Lacy et al., PLASMA HYDROGEN-PEROXIDE PRODUCTION IN HYPERTENSIVES AND NORMOTENSIVESUBJECTS AT GENETIC RISK OF HYPERTENSION, Journal of hypertension, 16(3), 1998, pp. 291-303
Background Oxygen free radicals may play roles in hypertension both in
arteriolar constriction and in formation of lesions. Objective To qua
ntify free radical production in blood plasma of genetic hypertensives
. Design Hydrogen peroxide levels were measured, because it is one of
the most stable reactive oxygen species. Methods An electrode techniqu
e was used to determine plasma hydrogen peroxide levels after blockade
of endogenous catalase with sodium azide. This method was validated b
y an independent spectrophotometric technique. Results Members of the
essential hypertensive group (n = 21) had higher plasma hydrogen perox
ide levels (3.16 +/- 0.14 versus 2.50 +/- 0.16 mu mol/l, P = 0.005) th
an did members of the normotensive group (n = 29). Furthermore, within
the normotensive group, those with a family history of hypertension (
n = 15) exhibited higher hydrogen peroxide levels (2.83 +/- 0.27 versu
s 2.14 +/- 0.13 mu mol/l, P = 0.03) than did those without such a fami
ly history (n = 14). Plasma hydrogen peroxide levels in these 50 subje
cts were correlated to their mean arterial pressures (r = 0.54, P < 0.
001). When hypertensives were grouped with normotensives without a fam
ily history of hypertension, the correlation improved (r = 0.70, P < 0
.001). Statistical analysis (two-way analysis of variance) revealed th
at a family history of hypertension was a better predictor of plasma h
ydrogen peroxide production than was blood pressure status (P = 0.003
versus P = 0.093). Further investigations showed that superoxide is pr
oduced in plasma and that one of its sources is xanthine oxidase. Conc
lusions Hydrogen peroxide is produced in blood plasma and elevation of
its level could constitute a pathogenic factor in vascular organ dama
ge attendant upon systemic hypertension. (C) 1998 Rapid Science Ltd.