Department of Pharmacology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812 - 8582, Japan
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ABSTRACT |
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We examined the effects of acute glucose overload
(pretreatment for 3 h with 23 mM D-glucose) on the
cellular productivity of nitric oxide (NO) in bovine aortic endothelial
cells (BAEC). We had previously reported (Kimura C, Oike M, and Ito Y. Circ Res, 82: 677-685, 1998) that glucose overload
impairs Ca2+ mobilization due to an accumulation of
superoxide anions (O2) in BAEC. In control cells, ATP
induced an increase in NO production, assessed by diaminofluorescein 2 (DAF-2), an NO-sensitive fluorescent dye, mainly due to
Ca2+ entry. In contrast, ATP-induced increase in DAF-2
fluorescence was impaired by glucose overload, which was restored by
superoxide dismutase, but not by catalase or deferoxamine. Furthermore,
pyrogallol, an O2
donor, also attenuated ATP-induced
increase in DAF-2 fluorescence. In contrast, a nonspecific
intracellular Ca2+ concentration increase induced by the
Ca2+ ionophore A-23187, which depletes the intracellular
store sites, elevated DAF-2 fluorescence in both control and high
D-glucose-treated cells in Ca2+-free solution.
These results indicate that glucose overload impairs NO production by
the O2
-mediated attenuation of Ca2+ entry.
calcium; superoxide; diaminofluorescein 2
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INTRODUCTION |
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CARDIOVASCULAR DISEASE, including coronary heart disease, stroke, and peripheral vascular disease, is the most important cause of mortality and morbidity among patients with diabetes mellitus (1, 15, 31), in which impairment of endothelial functions may be involved (19). As vascular endothelium plays its physiological roles by producing various mediators, including nitric oxide (NO) (23), the production of these endothelium-derived substances might be impaired in hyperglycemic conditions. This idea is supported in a previous report, showing that the aortic ring from diabetic rabbit failed to induce endothelium-derived relaxation in response to acetylcholine (34).
Accumulation of superoxide anion (O2) is one of the
reported candidates for the pathogenesis of vascular and/or endothelial damage in a diabetic environment. Excess glucose causes autooxidation of glucose and nonenzymatic protein glycation, both of which generate O2
(40). Metabolism of excess
D-glucose via its collateral pathway, the polyol pathway,
increases the NADH/NAD+ ratio, which results in the
activation of protein kinase C and phospholipase A2.
Prostaglandins are then synthesized by cyclooxygenase, which is capable
of generating O2
as an intermediate (34,
39). Fructose, a product of the polyol pathway, also generates
O2
, because it induces protein glycation more
efficiently than glucose (33). Furthermore, it has been
reported that the activity of endogenous superoxide dismutase (SOD) is
suppressed by hyperglycemia due to glycation (2). We have
previously shown (12) that acute glucose overload
abolishes ATP-induced Ca2+ oscillations by inhibiting
Ca2+ release-activated Ca2+ entry (CRAC) and
Ca2+ extrusion and by accelerating Ca2+ leak
from the intracellular Ca2+ store sites in bovine aortic
endothelial cells (BAEC). Normally, vascular endothelium produces NO in
response to the elevation of intracellular Ca2+
concentration ([Ca2+]i), which complexes with
calmodulin (CaM), and the Ca2+-CaM complex stimulates NO
synthase (NOS) to produce NO (24). Therefore, our previous
findings raise a question that needs to be clarified, i.e., whether
these impairments of Ca2+ homeostasis are responsible for
the attenuation of endothelium-derived vasodilatation in the
hyperglycemic condition.
For the measurement of cellular NO production, direct measurement of released NO by porphyrinic microsensor (20) or measurement of its metabolite, nitrite, by the Griess method (38) has been used. Diaminofluorescein 2 (DAF-2) has been developed recently as an NO-sensitive fluorescent dye, whose fluorescence was shown to correlate with the NO concentration from submicromolar levels (14). Furthermore, intracellular production of NO has been measured successfully from living cells by use of a membrane-permeable form of DAF-2, diacetylated DAF-2 (DAF-2/DA), in rat aortic smooth muscle cells (14) and BAEC (11). The major advantage of using DAF-2 is that it enables the measurement of intracellular NO production from living cells after any arbitrary pretreatment of the cell, including glucose overload.
We examined the characteristics of cellular NO production in
hyperglycemic conditions in BAEC by using DAF-2. In the present study,
we used ATP to induce NO production in BAEC. We recently reported
(27) that ATP is released from BAEC in response to mechanical stress. Because vascular endothelium shows its various physiological functions autonomically in response to mechanical stress
(5), we supposed that ATP-induced cellular responses play
an important role in endothelial physiology. The results obtained
indicate that glucose overload attenuates endothelial NO production,
and that this can be attributed mainly to the
O2-mediated impairment of Ca2+
mobilization that we previously clarified.
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METHODS |
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Culture of BAEC.
Bovine thoracic aorta of 1-yr-old calf was obtained from the local
slaughterhouse. Endothelial cells were scraped off from the intima with
the edge of a razor. Collected endothelial cells were cultured in DMEM
(Life Technologies, Rockville, MD) containing 10% fetal calf serum
under 5% CO2-95% air at 37°C. Cells of a second
subculture were used in the present experiment. Cells were seeded,
either on coverslips for measuring [Ca2+]i
and NO production or on a 96-well culture plate for measuring O2 generation, and were cultured for
4 days after
seeding. Identification of endothelial cells was confirmed by the
specific uptake of acetylated low-density lipoprotein.
Measurement of [Ca2+]i. [Ca2+]i was measured from nonconfluent single cells by use of an Attofluor digital fluorescence microscopy system (Atto Instruments, Rockville, MD). Cells were loaded with fura 2 by incubation with 1 µM fura 2-AM (Dojindo, Kumamoto, Japan) for 20 min at 37°C. Fura 2 was excited at two alternative wavelengths (340 and 380 nm), and the emitted fura 2 fluorescence images of 510-nm wavelength were recorded into a rewritable optical disc recorder (LQ-4100A, Panasonic, Osaka, Japan) at a rate of ~1 Hz. For each cell, fluorescence intensities excited at 340 and 380 nm (F340 and F380, respectively) were calculated from each image, and these data were converted to fluorescence ratio (F340/F380) and apparent [Ca2+]i as previously reported (27).
Measurement of O2 by MCLA.
We measured the generation of O2
in BAEC by
using an O2
-sensitive luciferin derivative,
2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin-3-one (MCLA; Tokyo Kasei, Tokyo, Japan) (26). Cells
were cultured for 4 days on a 96-well culture plate, and the
culture medium was replaced with Krebs or high-glucose Krebs solutions
and incubated for 3 h. Then the solution was replaced with 50 µl
of 1µM MCLA-containing solutions, and illuminated photons were
counted for 10 min with a luminescence detection system (Argus-50/2D
luminometer, Hamamatsu Photonics, Hamamatsu, Japan). It has been
reported that MCLA chemiluminescence is highly specific for
O2
and singlet molecular oxygen
(1O2) (26). We used superoxide
dismutase (SOD) to distinguish between chemiluminescence of
O2
and 1O2, because SOD does
not scavenge 1O2 (8). Because it
is difficult to calibrate MCLA chemiluminescence into absolute values
of O2
(25), we expressed the amount of
O2
as an equivalent concentration of xanthine
oxidase, which reacts with xanthine and generates O2
in a concentration-dependent manner (see inset of Fig. 2).
Measurement of intracellular production of NO.
NO was measured by use of DAF-2, an NO-sensitive fluorescent dye
(14). Cells were loaded with 10 µM DAF-2/DA (Daiichi
Pure Chemicals, Tokyo, Japan) for 30 min at 37°C. The DAF-2
fluorescence was measured by use of the same equipment as for
[Ca2+]i measurements but with a different
filter set, i.e., excitation at 490 nm and emission at 515 nm. Because
we found in the preliminary experiment that the frequent application of
the excitation wavelength quenches DAF-2 fluorescence, we applied the
excitation wavelength with an interval of 30 s. Therefore,
temporal resolution of DAF-2 fluorescence was inevitably lower than
that of [Ca2+]i in the present study. It has
been reported that DAF-2 fluorescence increases almost linearly with
the NO concentration (14); therefore, we expressed the
intracellular NO production as the net increment of DAF-2 fluorescence
in 15 min relative to its basal value. Because NO synthase (NOS)
produces O2 instead of NO in the absence of a
sufficient concentration of L-arginine (30),
we added a maximal concentration of L-arginine (10 mM) to
all solutions used for NO measurement, except for the experiment with
N
-nitro-L-arginine methyl ester
(L-NAME)-treated cells. The solutions were alkalized by the
addition of a high concentration of L-arginine, and we
therefore readjusted the pH to 7.3 with HCl.
Drugs and solutions. The standard extracellular solution was a modified Krebs solution (1.5 mM Ca2+ solution) containing (in mM): 132 NaCl, 5.9 KCl, 1.2 MgCl2, 1.5 CaCl2, 11.5 glucose, 11.5 HEPES, with pH adjusted to 7.3 with NaOH. High-glucose solution was made by replacing 6 mM NaCl with 11.5 mM D- or L-glucose, and Ca2+-free solution was made by replacing 1.5 mM CaCl2 with 1 mM EGTA. The bath was perfused continuously with these solutions at a rate of 1.5 ml/min.
Thapsigargin and cyclopiazonic acid (CPA), inhibitors of endoplasmic Ca2+-ATPase, were used to deplete intracellular Ca2+ store sites. Neomycin was used to inhibit phospholipase C. We used SOD, a scavenger of O2Exposure of cells to high-glucose environment.
In this study, BAEC were pretreated for 3 h with either 11.5 mM
D-glucose solution (normal glucose), 23 mM
D-glucose solution (high D-glucose) or 11.5 mM
D-glucose + 11.5 mM L-glucose solution (high L-glucose). Because a lower D-glucose
concentration (5.8 mM) did not show any difference in Ca2+
mobilizing properties and DAF-2 fluorescence from those treated with
11.5 mM glucose, we used 11.5 mM glucose, employed in our laboratory as
normal Krebs, as "normal glucose" solution. We did not examine the
chronic effects of glucose overload, because culture medium, which
contains sufficient concentration of antioxidative amino acids and
vitamins, would have had to be used for pretreating the cells for days,
and this would have artificially reduced the impairing effects of
high-glucose-induced O2 accumulation.
Data analysis. Pooled data are given as means ± SE, and statistical significance was determined with Student's unpaired t-test and one-way ANOVA for comparing two groups and more than three groups, respectively. Probabilities of <5% (P < 0.05) were regarded as significant.
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RESULTS |
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Effects of glucose overload on Ca2+ mobilization in
BAEC.
First, we confirmed our previous findings, i.e., that
D-glucose overload impairs Ca2+ mobilization
due to the accumulation of O2 (12). As
shown in Fig. 1A, ATP (1 µM)
induced Ca2+ oscillations in Ca2+-containing
Krebs solution in control cells treated with normal glucose.
Ca2+ oscillations were not spontaneous, since perfusion of
normal Krebs solution alone without ATP did not induce any
Ca2+ responses. In high D-glucose-treated cells
(Fig. 1B), but not in high L-glucose-treated
cells (not shown), ATP (1 µM)-induced Ca2+ oscillations
were abolished. Impairment of ATP-induced Ca2+ oscillations
in high D-glucose-treated cells was restored by SOD (100 U/ml). However, catalase (1,200 U/ml) and deferoxamine (1 mM) did not
reverse the impairment of Ca2+ oscillation in high
D-glucose-treated cells (not shown).
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Generation of O2 in high-glucose-treated cells.
We then measured the amount of O2
released from BAEC
into extracellular space by the use of MCLA (26). As shown
in Fig. 2, the amount of
O2
generated from BAEC after the incubation with
normal glucose for 3 h was equivalent to 0.018 ± 0.005 mU/ml
of xanthine oxidase (n = 10). In contrast, the value
was significantly higher in high D-glucose (0.139 ± 0.003 mU/ml; n = 10) but similar in high
L-glucose solution (0.020 ± 0.008 mU/ml;
n = 10). This was completely scavenged by SOD (below
the detection limit) but not by catalase or deferoxamine (Fig. 2),
thereby suggesting that glucose overload-induced MCLA chemiluminescence
was due to the generation of O2
but not
1O2. On the other hand, O2
was not detected in normal Krebs or high D-glucose
solutions without endothelium. These suggest that O2
is actually generated and released from BAEC in high
D-glucose condition and that SOD completely scavenges the
released O2
.
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High D-glucose attenuates NO production in BAEC.
ATP (1 µM) induced a gradual increase in DAF-2 fluorescence in normal
glucose-treated cells (Fig.
3A). It
should be noted that the reaction between DAF-2 and NO is irreversible
(14); therefore, the accumulated level of DAF-2
fluorescence corresponds to the total amount of cellular NO production
of the period. The ATP-induced increase in DAF-2 fluorescence was
suppressed in cells pretreated with 0.1 mM L-NAME for 30 min, suggesting that DAF-2 fluorescence is linked to the cellular NO
production (Fig. 3A). ATP increased DAF-2 fluorescence in a
concentration-dependent manner in both Ca2+-containing and
Ca2+-free solutions (Fig. 3C). Pretreatment with
1 mM neomycin for 30 min suppressed the 10 µM ATP-induced increase in
DAF-2 fluorescence in Ca2+-free solution (Fig.
3C), thereby indicating that the increase in DAF-2
fluorescence in Ca2+-free solution was due to
Ca2+ release from intracellular store sites in BAEC.
However, the increment of DAF-2 fluorescence was significantly smaller
in Ca2+-free solution than in Krebs solution, and ATP <1
µM did not induce a DAF-2 increase in Ca2+-free solution
(Fig. 3C).
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O2 is responsible for the attenuation of NO
production in glucose-overloaded BAEC.
We have shown that impairment of Ca2+ homeostasis by
D-glucose overload is due to O2
(Fig. 1
and Ref. 12), which is markedly accumulated in the extracellular space in the high D-glucose condition (Fig.
2). Thus we pretreated the cells with high D-glucose
solution in the presence of SOD, catalase, or deferoxamine, and we
measured ATP-induced NO production. SOD-treated cells showed an
increase in DAF-2 fluorescence in response to 1 µM ATP similar to
that in control cells (Fig. 5). In
contrast, catalase and deferoxamine did not restore the glucose
overload-induced attenuation of NO production (Fig. 5).
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DISCUSSION |
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Many investigators have reported that the high-glucose condition
attenuates endothelium-derived vasorelaxation (7, 22, 29,
35). Therefore, it has been speculated that glucose overload would cause the impairment of NO release and/or the increased destruction of released NO. Langenstroer and Pieper (16)
reported that the resting level of NO release was rather increased in
diabetic rat aorta but that the endothelial functions were nevertheless attenuated since the destruction of NO was increased by
O2. Their report is supported by the fact
that NO easily reacts with O2
to generate
peroxynitrite (9). The present results indicate that the
production of NO is also impaired by acute glucose overload in BAEC due
to the O2
-induced attenuation of Ca2+
mobilization. The impairing effects of glucose overload are not due to
the nonspecific action of glucose but to the metabolism of excess
glucose, because nonmetabolizable L-glucose did not show an
inhibitory effect on DAF-2 fluorescence (Fig. 3B). We measured the intracellular NO production induced by ATP and A-23187 with DAF-2; therefore, it should be noted that the present results did
not take into account the possible destruction of released NO by
O2
. It should also be noted that the present study
was performed with the use of cultured endothelial cells, whose
properties may not be identical to those in vivo, and DAF-2
fluorescence may have been influenced by dye quenching. Furthermore,
the present study did not investigate the possible involvement of other
cellular changes, such as the activation of protein kinase C
(13) and the polyol pathway (3) in glucose
overload-induced endothelial dysfunction.
Cosentino et al. (4) reported that long-term incubation of human endothelium with 22.2 mM glucose for 5 days increased the expression level of endothelial NOS mRNA and ionomycin-induced nitrite production. However, we consider that this does not contradict the present results, because the agonist-induced Ca2+ mobilizing pathways were bypassed by use of the Ca2+ ionophore ionomycin in their report. Actually we observed that A-23187-induced NO production was not affected by glucose overload (Fig. 4). Therefore, although agonist-induced, Ca2+-dependent NO production requires CaM and NOS (24), we suppose that the attenuation of NO production by acute glucose overload can be attributed to the impairment of Ca2+ homeostasis but not to the alteration of these molecules. We have shown that glucose overload abolishes Ca2+ oscillations (Fig. 1 and Ref. 12). Generation of Ca2+ oscillations requires integrity of various Ca2+ pathways, i.e., Ca2+ release from the intracellular store sites, extrusion of released Ca2+ out of the cell, Ca2+ entry from the extracellular space, and reloading of the intracellular Ca2+ store sites (32). Therefore, although 1 µM ATP induced Ca2+ transient in high glucose-treated cells also (Fig. 1B), the fact that Ca2+ oscillations were abolished would indicate that some of the Ca2+ mobilizing pathways were impaired. Because we observed that CRAC was attenuated by glucose overload (Fig. 1, D and E), we suppose that at least the impairment of CRAC was involved in the disappearance of Ca2+ oscillations in high glucose-treated cells. Lantoine et al. (17) reported that, in human umbilical cord vein endothelial cells, NO production is triggered by Ca2+ entry from the extracellular space but not by Ca2+ release from store sites. The authors speculated that this was due to the submembrane localization of endothelial NOS. We also observed that ATP-induced NO production was much larger in the Ca2+-containing solution than in the Ca2+-free solution (Fig. 3C), suggesting the preferential production of NO by entered Ca2+, especially in the case of low levels of stimulation. However, considerable elevation of DAF-2 fluorescence was also induced by a high concentration of ATP or A-23187 in Ca2+-free solution, thereby indicating that depletion of the intracellular Ca2+ store sites leads to NO production in BAEC. As shown in Fig. 4C, store depletion-induced NO production was not inhibited by glucose overload. Therefore, we hypothesized that the impairment of CRAC plays a central role in the attenuation of ATP-induced NO production by acute D-glucose overload. This is not selective for ATP-induced NO production, since glucose overload also attenuated 0.3 µM ACh-induced NO production (C. Kimura and M. Oike, unpublished observation).
A high-glucose environment leads to the accumulation of
O2, as summarized in the introductory section. In the
present experiment, SOD, but not catalase or deferoxamine, restored
high-glucose-induced impairment of Ca2+ homeostasis (Fig.
1) and NO production (Fig. 5). Furthermore, we confirmed the impairing
effects of O2
on Ca2+ homeostasis and NO
production by pretreating the cell with pyrogallol (Fig. 6). Therefore,
we conclude that O2
, which affects
Ca2+ homeostasis, is responsible for the
impairment of NO production in the hyperglycemic condition. Using MCLA
chemiluminescence, we confirmed that the high D-glucose
condition induces the increased generation and/or decreased scavenging
of O2
, which was abolished by SOD (Fig. 2). MCLA is a
water-soluble substance that does not permeate the cell membrane
(25), and MCLA chemiluminescence was not detected in
cell-free culture wells (Fig. 2). Therefore, although
O2
is supposed to be generated inside the cell as a
result of glucose metabolism, it seems that O2
permeates the membrane and is released into the extracellular space and
then affects Ca2+ pathways of the cell and/or neighboring
cells. We suppose that this is why SOD, a large molecule (31 kDa) that
could not penetrate the cell membrane, scavenged the intracellularly
generated O2
and restored
Ca2+ mobilization and NO production. Graier
et al. (10) reported that the high-glucose-induced
generation of O2
enhanced endothelium-derived
relaxing factor formation in porcine aortic endothelium. They incubated
the cells for 24 h with a high-glucose culture medium and observed
that bradykinin-induced Ca2+ transient and cGMP
concentration were augmented in high-glucose-treated cells due to
O2
production. However, the present study and many
reports from other laboratories (7, 22, 28, 35) indicate
that glucose overload attenuates endothelium-derived relaxation or NO
production. Although it may be possible that this discrepancy was due
to the differences in the period of glucose overload, species, and
agonist, we could not identify the precise reason for the discrepancy.
It is well known that the impairment of endothelial constitutive NO
production would result not only in the loss of local control of
vascular tonus but also in the development of atherosclerosis (36), heart failure (6), or cerebrovascular
events (37). Therefore, the mechanism shown in the present
study is probably involved in the pathogenesis of some diabetic
vascular complications. In conclusion, we have shown that acute glucose
overload attenuates endothelial NO production by the impairment of
Ca2+ homeostasis, especially CRAC. Our results also suggest
that scavenging O2 might be a good therapeutic
approach to diabetic vascular complications.
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ACKNOWLEDGEMENTS |
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The authors thank Dr. Guy Droogmans for critical reading of the manuscript.
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FOOTNOTES |
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This work was supported by a grant-in-aid from the Japan Society for the promotion of Science (JSPS, 11003235) and the Japan Heart Foundation (C. Kimura). C. Kimura is a research fellow of JSPS.
Address for reprint requests and other correspondence: M.Oike, Dept. of Pharmacology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan (E-mail: moike{at}pharmaco.med.kyushu-u.ac.jp).
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Received 3 April 2000; accepted in final form 21 September 2000.
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REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Andresen, JL,
Rasmussen LM,
and
Ledet T.
Diabetic macroangiopathy and atherosclerosis.
Diabetes
45:
S91-S94,
1996[ISI][Medline].
2.
Arai, K,
Iizuka S,
Tada Y,
Oikawa K,
and
Taniguchi N.
Increase in the glucosylated form of erythrocyte Cu-Zn-superoxide dismutase in diabetes and close association of the nonenzymatic glucosylation with the enzyme activity.
Biochim Biophys Acta
924:
292-296,
1987[ISI][Medline].
3.
Bylander, JE,
and
Sens DA.
Elicitation of sorbitol accumulation in cultured human proximal tubule cells by elevated glucose concentrations.
Diabetes
39:
949-954,
1990[Abstract].
4.
Cosentino, F,
Hishikawa K,
Katusic ZS,
and
Luscher TF.
High glucose increases nitric oxide synthase expression and superoxide anion generation in human aortic endothelial cells.
Circulation
96:
25-28,
1997
5.
Davies, PF.
Flow-mediated endothelial mechanotransduction.
Physiol Rev
75:
519-560,
1995
6.
Ferrari, R,
Bachetti T,
Agnoletti L,
Comini L,
and
Curello S.
Endothelial function and dysfunction in heart failure.
Eur Heart J
19:
G41-G47,
1998[ISI][Medline].
7.
Giugliano, D,
Ceriello A,
and
Paolisso G.
Oxidative stress and diabetic vascular complications.
Diabetes Care
19:
257-267,
1996[Abstract].
8.
Goda, K,
Kimura T,
Thayer AL,
Kees K,
and
Schaap AP.
Singlet molecular oxygen in biological systems: non-quenching of singlet oxygen-mediated chemiluminescence by superoxide dismutase.
Biochem Biophys Res Commun
58:
660-666,
1974[ISI][Medline].
9.
Goldstein, S,
and
Czapski G.
The reaction of NO with O2
and HO2
: a pulse radiolysis study.
Free Radic Biol Med
19:
505-510,
1995[ISI][Medline].
10.
Graier, WF,
Simecek S,
Kukovetz WR,
and
Kostner GM.
High D-glucose-induced changes in endothelial Ca2+/EDRF signaling are due to generation of superoxide anions.
Diabetes
45:
1386-1395,
1996[Abstract].
11.
Igarashi, J,
Thatte HS,
Prabhakar P,
Golan DE,
and
Michel T.
Calcium-independent activation of endothelial nitric oxide synthase by ceramide.
Proc Natl Acad Sci USA
96:
12583-12588,
1999
12.
Kimura, C,
Oike M,
and
Ito Y.
Acute glucose overload abolishes Ca2+ oscillation in cultured endothelial cells from bovine aorta: a possible role of superoxide anion.
Circ Res
82:
677-685,
1998
13.
King, GL,
Kunisaki M,
Nishio Y,
Inoguchi T,
Shiba T,
and
Xia P.
Biochemical and molecular mechanisms in the development of diabetic vascular complications.
Diabetes
45:
S105-S108,
1996[ISI][Medline].
14.
Kojima, H,
Nakatsubo N,
Kikuchi K,
Kawahara S,
Kirino Y,
Nagoshi H,
Hirata Y,
and
Nagano T.
Detection and imaging of nitric oxide with novel fluorescent indicators: diaminofluoresceins.
Anal Chem
70:
2446-2453,
1998[ISI][Medline].
15.
Laakso, M.
Hyperglycemia and cardiovascular disease in type 2 diabetes.
Diabetes
48:
937-942,
1999[Abstract].
16.
Langenstroer, P,
and
Pieper GM.
Regulation of spontaneous EDRF release in diabetic rat aorta by oxygen free radicals.
Am J Physiol Heart Circ Physiol
263:
H257-H265,
1992
17.
Lantoine, F,
Iouzalen L,
Devynck MA,
Millanvoye Van Brussel E,
and
David Dufilho M.
Nitric oxide production in human endothelial cells stimulated by histamine requires Ca2+ influx.
Biochem J
330:
695-699,
1998[ISI][Medline].
18.
Lievremont, JP,
Rizzuto R,
Hendershot L,
and
Meldolesi J.
BiP, a major chaperone protein of the endoplasmic reticulum lumen, plays a direct and important role in the storage of the rapidly exchanging pool of Ca2+.
J Biol Chem
272:
30873-30879,
1997
19.
Lorenzi, M,
and
Cagliero E.
Pathobiology of endothelial and other vascular cells in diabetes mellitus. Call for data.
Diabetes
40:
653-659,
1991[Abstract].
20.
Malinski, T,
and
Taha Z.
Nitric oxide release from a single cell measured in situ by a porphyrinic-based microsensor.
Nature
358:
676-678,
1992[ISI][Medline].
21.
Marklund, S,
and
Marklund G.
Involvement of the superoxide anion radical in the autoxidation of pyrogallol and a convenient assay for superoxide dismutase.
Eur J Biochem
47:
469-474,
1974[ISI][Medline].
22.
Mayhan, WG.
Impairment of endothelium-dependent dilatation of cerebral arterioles during diabetes mellitus.
Am J Physiol Heart Circ Physiol
256:
H621-H625,
1989
23.
Moncada, S,
Palmer RM,
and
Higgs EA.
The discovery of nitric oxide as the endogenous nitrovasodilator.
Hypertension
12:
365-372,
1988[Abstract].
24.
Moncada, S,
Palmer RM,
and
Higgs EA.
Nitric oxide: physiology, pathophysiology, and pharmacology.
Pharmacol Rev
43:
109-142,
1991[ISI][Medline].
25.
Nakano, M.
Detection of active oxygen species in biological systems.
Cell Mol Neurobiol
18:
565-579,
1998[ISI][Medline].
26.
Nishida, A,
Kimura H,
Nakano M,
and
Goto T.
A sensitive and specific chemiluminescence method for estimating the ability of human granulocytes and monocytes to generate O2.
Clin Chim Acta
179:
177-181,
1989[ISI][Medline].
27.
Oike, M,
Kimura C,
Koyama T,
Yoshikawa M,
and
Ito Y.
Hypotonic stress-induced dual Ca2+ responses in bovine aortic endothelial cells.
Am J Physiol Heart Circ Physiol
279:
H630-H638,
2000
28.
Pieper, GM.
Review of alterations in endothelial nitric oxide production in diabetes: protective role of arginine on endothelial dysfunction.
Hypertension
31:
1047-1060,
1998
29.
Pieper, GM,
Meier DA,
and
Hager SR.
Endothelial dysfunction in a model of hyperglycemia and hyperinsulinemia.
Am J Physiol Heart Circ Physiol
269:
H845-H850,
1995
30.
Pou, S,
Pou WS,
Bredt DS,
Snyder SH,
and
Rosen GM.
Generation of superoxide by purified brain nitric oxide synthase.
J Biol Chem
267:
24173-24176,
1992
31.
Ruderman, NB,
Williamson JR,
and
Brownlee M.
Glucose and diabetic vascular disease.
FASEB J
6:
2905-2914,
1992
32.
Sneyd, J,
Keizer J,
and
Sanderson MJ.
Mechanisms of calcium oscillations and waves: a quantitative analysis.
FASEB J
9:
1463-1472,
1995
33.
Suarez, G,
Rajaram R,
Oronsky AL,
and
Gawinowicz MA.
Nonenzymatic glycation of bovine serum albumin by fructose (fructation). Comparison with the Maillard reaction initiated by glucose.
J Biol Chem
264:
3674-3679,
1989
34.
Tesfamariam, B.
Free radicals in diabetic endothelial cell dysfunction.
Free Radic Biol Med
16:
383-391,
1994[ISI][Medline].
35.
Tesfamariam, B,
and
Cohen RA.
Free radicals mediate endothelial cell dysfunction caused by elevated glucose.
Am J Physiol Heart Circ Physiol
263:
H321-H326,
1992
36.
Vanhoutte, PM.
Endothelial dysfunction and atherosclerosis.
Eur Heart J
18:
E19-29,
1997[ISI][Medline].
37.
Verrecchia, C,
Buisson A,
Lakhmeche N,
Plotkine M,
and
Boulu RG.
Nitric oxide and cerebral ischemia.
Ann NY Acad Sci
738:
341-347,
1994[ISI][Medline].
38.
Wang, Y,
Shin WS,
Kawaguchi H,
Inukai M,
Kato M,
Sakamoto A,
Uehara Y,
Miyamoto M,
Shimamoto N,
Korenaga R,
Ando J,
and
Toyooka T.
Contribution of sustained Ca2+ elevation for nitric oxide production in endothelial cells and subsequent modulation of Ca2+ transient in vascular smooth muscle cells in coculture.
J Biol Chem
271:
5647-5655,
1996
39.
Williamson, JR,
Chang K,
Frangos M,
Hasan KS,
Ido Y,
Kawamura T,
Nyengaard JR,
van den Enden M,
Kilo C,
and
Tilton RG.
Hyperglycemic pseudohypoxia and diabetic complications.
Diabetes
42:
801-813,
1993[Abstract].
40.
Wolff, SP,
Jiang ZY,
and
Hunt JV.
Protein glycation and oxidative stress in diabetes mellitus and ageing.
Free Radic Biol Med
10:
339-352,
1991[ISI][Medline].