Hepes may stimulate cultured endothelial cells to make growth-retarding oxygen metabolites

Bowman, C. Michael; Berger, E.; Butler, Elaine N.; Toth, K M; Repine, John E.

doi:10.1007/bf02621350

Cited by 29 publications

(11 citation statements)

References 18 publications

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“…A NaHCO 3 buffer was used instead of a HEPES buffer because the HEPES buffer induced more unstable or variable responses under ischemic conditions than the NaHCO 3 buffer. The reason is unknown, but it may relate to the ®nding that HEPES buffer could have some cytotoxic effects due to the production of toxic oxygen metabolites under certain conditions (Bowman et al, 1985;Zigler et al, 1985). This glucose-free solution was composed of the following (mM, pH 7 .…”

Section: Solutions and Application Of Test Solutionsmentioning

confidence: 99%

Intracellular Ca2+Changes Induced by in vitro Ischemia in Rat Retinal Slices

Kuriyama

Nakagawa²,

Tsuda³

2001

Experimental Eye Research

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Section: Solutions and Application Of Test Solutionsmentioning

confidence: 99%

Intracellular Ca2+Changes Induced by in vitro Ischemia in Rat Retinal Slices

Kuriyama

Nakagawa²,

Tsuda³

2001

Experimental Eye Research

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“…A spontaneous activation can also result from the effect of the medium used for Ž . incubating the haemocytes, as shown in vertebrate blood cells Bowman et al, 1985 and, in our study, when incubating haemocytes in Dulbecco's PBS. High base activity values may reveal stressful or injurious situations due to in vitro factors.…”

mentioning

confidence: 97%

Measurement of reactive oxygen intermediate production in haemocytes of the penaeid shrimp, Penaeus vannamei

et al. 2000

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Ž. A spectrophotometric nitroblue tetrazolium NBT reduction assay was used to demonstrate the Ž y . production of superoxide anions O by haemocytes of the white shrimp Penaeus Õannamei. It 2 was found that haemocytes, without receiving an experimental stimulant, showed a rather high Ž background activity. Therefore, optimal parameters number of haemocytes, type of incubation . medium, type and concentration of stimulants were first established, in order to obtain a reliable and reproducible quantitative assay. With this optimized assay, and using specific inhibitors, it was shown that it is indeed the production of O y that was measured. Activities varied strongly 2 among individual shrimp specimens. Live bacteria, among these Vibrio strains, induced O y 2 production in the haemocytes, in a dose-dependent manner. Whereas Vibrio anguillarum and a probiotic strain of V. alginolyticus evoked clear reactions, a pathogenic strain of V. harÕeyi failed to elicit O y production in the haemocytes. It is discussed that this may explain this strain's 2 capability of evading the host's oxidative microbicidal activity, which would be a virulence factor in these bacteria. Heat-killed bacteria hardly induced NBT reduction in the cells. The fungicide propiconazole or Tilt w , found as a pollutant in the aquatic environment where the shrimp are reared, was tested for its effect on NBT reduction by the haemocytes. In haemocytes that did not receive an experimental stimulant, Tilt w induced the reduction of NBT in a dose-dependent manner. In experimentally stimulated haemocytes, however, Tilt w strongly reduced the reaction upon the stimulant PMA. Probable explanations for these seemingly controversial effects of Tilt w are discussed, as are possible consequences of this sort of pollutants for shrimp aquaculture. This easy to perform and relatively cheap and simple quantitative assay for measuring the activity of an oxidative microbicidal mechanism in shrimp haemocytes, appears quite reliable and may therefore prove to be a valuable tool for monitoring shrimp health and immunologic status. q

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“…HEPES was excluded from the final serum-free media since this buffer has been reported to stimulate endothelial cells to produce reactive oxygen metabolites. 40 The use of chloramphenicol during all steps of LDL purification protects against contamination with gram-negative bacterial endotoxins, which are known to induce PGI 2 production in endothelial cells. 41 During LDL preparation, NaN 3…”

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confidence: 99%

Oxidized low density lipoprotein stimulates prostacyclin production by adult human vascular endothelial cells.

1988

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Interactions between vascular endothelium and low density lipoprotein (LDL) have been implicated in the development of atherosclerosis. The effect of normal and oxidized LDL (Ox-LDL) on prostaglandin release by cultured adult human saphenous vein endothelial cells was investigated. Ox-LDL induced a rapid release of prostacyclin (PGI 2 ) to levels which were several-fold higher than those observed with control LDL. PGI 2 release was concentration-dependent and was biphasic, with a first peak occurring within 30 minutes (followed by a decrease), and a second peak occurring after several hours of incubation. PGI 2 production was inhibited by lipoproteindepleted serum and by indomethacin, an antagonist of cyclooxygenase activity. These cells produced mainly PGF^, with some PGE 2 and PGI 2 when stimulated by the ionophore A23187 at confluency. However, among these prostanoids, mainly PGI 2 was produced in response to Ox-LDL. The data indicate that Ox-LDL induces the production of PGI 2 by human vascular endothelial cells. Since Ox-LDL is cytotoxic, this phenomenon may be a manifestation of an early response to injury. (Arteriosclerosis 8:810-818, November/December 1988) T he interaction of low density lipoprotein (LDL) with endothelial cells is of significant interest to researchers in the field of atherosclerosis. LDL is toxic to endothelial cells cultured in serum-free medium.1 -2 LDL cytotoxicity is due to oxidation of its lipid moiety, and oxidized LDL (Ox-LDL) cytotoxicity is prevented by the use of antioxidants in vitro.3 -6 Endothelial cells, smooth muscle cells,' and leukocytes oxidize LDL in vitro in a manner similar to the oxidation catalyzed by transition metals. 5789Ox-LDL inhibits macrophage mobility, is metabolized via the scavenger receptor, and induces cholesterol ester accumulation in the macrophage.9 -12 Ox-LDL may thus promote atherosclerosis.3 " 12 Prostacyclin (PGI 2 ) is a potent vasodilator and decreases platelet aggregation.13 PGI 2 is produced by endothelial cells, and increased levels of 2,3-dinor-6-keto-PGF 1(I , a major urinary metabolite of PGI 2 , have been observed in patients with atherosclerosis.141516 When endothelial cells are subjected to various forms of injury such as balloon catheter trauma, radiation, shear stress, or exposure to mellitin, PGI 2 is released. 17 -20 We tested the hypothesis that adult human vascular endothelial cells produce PGI 2 in response to Ox-LDL. The data presented support this hypothesis. Methods Tissue CultureHuman saphenous vein endothelial cell (HSVEC) cultures were prepared by collagenase digestion of unused saphenous vein sections obtained during coronary artery bypass surgery. 21 The use of normally discarded human tissues was approved by the Human Investigation Review Committee of the New England Medical Center, Boston, MA. The cells were grown on human fibronectin-coated dishes (1.5 /xg/cm 2 ) in Morgan's M-199 medium containing 25 mM HEPES, and supplemented with 5% fetal bovine serum (FBS), 50 /Ag/ml bovine endothelial cell growth factor, 10...

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Hepes may stimulate cultured endothelial cells to make growth-retarding oxygen metabolites

Cited by 29 publications

References 18 publications

Intracellular Ca2+Changes Induced by in vitro Ischemia in Rat Retinal Slices

Intracellular Ca2+Changes Induced by in vitro Ischemia in Rat Retinal Slices

Measurement of reactive oxygen intermediate production in haemocytes of the penaeid shrimp, Penaeus vannamei

Oxidized low density lipoprotein stimulates prostacyclin production by adult human vascular endothelial cells.

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