Passive cigarette smoking increases isoprostane formation

Passive smoking has been demonstrated to exert a variety of deleterious effects eventually resulting in vascular damage. Isoprostanes, a reliable marker of in vivo oxidation injury, have been shown to increase in active cigarette smoking. Data for passive smoking are lacking. We were examining the isoprostane 8-epi-PGF2alpha in 12 smokers and non-smokers exposed daily to passive cigarette smoke for 12 days. Plasma samples stored at liquid nitrogen from people having been examined earlier were used. Prevalues of 8-epi-PGF2alpha are higher in cigarette smokers. Exposure to passive smoking causes a significant increase in 8-epi-PGF2alpha in non-smokers, while in smokers there is only a trendwise increase. After repeated passive smoke exposure, 8-epi-PGF2alpha in non-smokers approaches the respective values of smokers. There is a significant correlation of 8-epi-PGF2alpha to the thromboxane (plasma, serum, conversion from exogenous precursor, 11-dehydro-TXB2) parameters (MDA, HHT- conversion) examined in these patients before. The findings document a significant temporary increase in in vivo oxidation injury due to passive smoke favouring development and/or progression of vascular disease.     

Effect of black tea on (iso-)prostaglandins and platelet aggregation in healthy volunteers

Flavonoids among others are found in tea. Many of them were shown to exhibit antioxidative action in vitro. We examined the effect of a 1-month consumption of 500 ml black tea containing 2.0 mg quercetin. While single tea consumption 2 h after finishing the intake did not affect any of the parameters (8-epi-PGF(2 alpha) in plasma and serum, 11-DH-TXB(2) and ADP-induced platelet aggregation) examined at all, 1-week consumption and even more than 1 month regular tea intake significantly decreased most of the parameters. The effect was somewhat more pronounced for females as compared with males, the values for 11-dehydro-thromboxane B(2) (11-DH-TXB(2)) and ADP-induced aggregation reached the level of significance in females only. These data show that regular daily black tea consumption for 1 month improves platelet function and decreases thromboxane and 8-epi-PGF(2 alpha) to a varying extent indicating a reduced in vivo oxidation injury.     

Increase of isoprostane 8-epi-PGF2 αafter restarting smoking

Isoprostanes are known as reliable markers of in vivo oxidation injury. Cigarette smoking has been shown to be associated with a significant increase in 8-epi-PGF(2alpha), a major member of this family of compounds. Quitting smoking reduces 8-epi-PGF(2alpha) values to normal within a couple of weeks only. In this follow-up we checked the 8-epi-PGF(2alpha), values in plasma, serum and urine in 28 people who restarted smoking after a quitting attempt of various duration. 8-epi-PGF(2alpha)shows a certain increase after restarting smoking reaching a maximum after already 1 week. Continuation of smoking does not significantly further increase 8-epi-PGF(2alpha). These data indicate a fast response of restarting as on quitting smoking on in vivo oxidation injury. The oxidation injury reflected by 8-epi-PGF(2alpha)may be a key pathogenetic mechanism in smoking-induced vascular injury.     

6-Oxo-PGF1alpha and 8-epi-PGF2alpha in human atherosclerotic vascular tissue.

Isoprostanes are a new family of compounds generated by the free radical catalyzed action on arachidonic acid. Formed during oxidation they have been claimed to be a reliable indicator of in vivo oxidation injury. We assessed the amount of 8-epi-PGF2alpha in human surgical specimens as compared to PGI2 (via its stable metabolite 6-oxo-PGF1alpha), the major compound generated by vascular tissue. 8-epi-PGF2alpha is low in normal vascular tissue as is the 8-epi-PGF2alpha/6-oxo-PGF1alpha ratio. The vessels of smokers in general exhibited an increased 8-epi-PGF2alpha (r=0.82) and a decreased 6-oxo-PGF1alpha (r=0.71). The 8-epi-PGF2alpha/6-oxo-PGF1alpha ratio is, not significantly, increased in vessels derived from hyperlipidemics and hypertensives. These findings indicate that lipid peroxidation occurs within the human arterial wall as evidenced by 8-epi-PGF2alpha, probably further decreasing the synthesis of PGI2 and promoting atherogenic mechanisms.     

Effect of giving up cigarette smoking and restarting in patients with clinically manifested atherosclerosis

Cigarette smoking, a key risk factor for the development of vascular disease, is associated with an increased 8-epi-prostaglandin (PG) F(2alpha). Elevated 8-epi-PGF(2alpha) has been found in vascular tissue, blood and urine as well. We examined the influence of quitting cigarette smoking in 71 patients (38 males, 33 females; aged 32-67 a) with clinically manifested atherosclerosis and various risk factors. In addition, in eight patients with hypercholesterolemia without clinical manifestation of atherosclerosis quitting smoking was monitored as well. Twenty-six of the patients with manifested atherosclerosis and five with hypercholesterolemia restarted and the isoprostanes in plasma, serum and urine were monitored in these patients as well. Quitting cigarette smoking induces an immediate decline becoming significant after 1 or 2 weeks. Restarting smoking results in an increase in 8-epi-PGF(2alpha) reaching prevalues within almost 1 week. These findings indicate that the in vivo oxidation injury associated with cigarette smoking quickly decreases after quitting but increases soon after restarting immediately.     

6-oxo-PGF(1 alpha)and 8-epi-PGF(2 alpha)in the arterial wall layers of various species: a comparison between intact and atherosclerotic areas

PGI(2)and 8-epi-prostaglandin(PG)F(2 alpha)are antagonizing compounds. For both a key role in vascular pathology has been hypothesized. The isoprostane 8-epi-PGF(2 alpha)and the stable derivative of PGI(2), 6-oxo-PGF(1 alpha)were determined immunologically in the arterial wall of various species including humans. Human arterial tissue contained the highest amounts of 8-epi-PGF(2 alpha)and synthesized the lowest PGI(2). A significant negative correlation between 8-epi-PGF(2 alpha)and 6-oxo-PGF(1 alpha)was observed. Atherosclerotic segments showed significantly higher 8-epi-PGF(2 alpha)and lower 6-oxo-PGF(1 alpha). 8-epi-PGF(2 alpha)in the intima was higher than in the media, the highest amounts being found in foam-cell rich areas. Synthetic (activated) smooth muscle cells were associated with an enhanced 8-epi-PGF(2 alpha)as well as 6-oxo-PGF(1 alpha). Tissue samples derived from smokers contained more 8-epi-PGF(2 alpha)and produced less PGI(2). The by far highest 8-epi-PGF(2 alpha)/6-oxo-PGF(1 alpha)ratio was found in foam cell rich areas. Similar findings were obtained in rabbit and in minipig arteries. The total 8-epi-PGF(2 alpha)/6-oxo-PGF(1 alpha)ratio is low in normal tissue, increases significantly in an active atherosclerotic process and seems to be even further increased in an inactive atherosclerotic process. These findings are providing an information on the extent of oxidation injury at various sites of different types of atherosclerotic process.     

Biomarkers of exposure and potential harm in adult smokers of 3-7 mg tar yield (Federal Trade Commission) cigarettes and in adult non-smokers.

The paper reports levels of 24-h urine nicotine and five of its major metabolites (expressed as nicotine-equivalents) and blood carboxyhaemoglobin as biomarkers of exposure to particulate- and gas-phase cigarette smoke, respectively, from an exploratory pilot study of adult smokers of 3.0-6.9 mg tar delivery (Federal Trade Commission (FTC) method) cigarettes. On multiple occasions over 6 weeks, blood high-sensitivity C-reactive protein (hs-CRP), fibrinogen, HDL- and LDL-cholesterol, and 24-h urine 8-epi-prostaglandin F2alpha (8-epi-PGF2alpha) and 11-dehydro-thromboxane B2 (11-dehydro-TxB2) were also evaluated as biomarkers of potential harm. All the biomarkers examined, except for LDL-cholesterol, discriminated with high sensitivity and specificity between adult smokers and non-smokers overall. Except for HDL-cholesterol, all biomarker medians were greater in adult smokers than in non-smokers: urine nicotine-equivalents 64.514 versus < 0.034 nmol mg-1 creatinine (p<0.001), carboxyhaemoglobin 4.0 versus 0.4% saturation (p<0.001), hs-CRP 0.27 versus 0.12 mg dl-1 (p=0.05), fibrinogen 292 versus 248 mg dl-1 (p<0.001), HDL-cholesterol 46 versus 53 mg dl-1 (p=0.003), LDL-cholesterol 119 versus 109 mg dl-1 (p=0.18), urine 8-epi-PGF2alpha 1935 versus 1034 pg mg-1 creatinine (p<0.001) and urine 11-dehydro-TxB2 973 versus 710 pg mg-1 creatinine (p<0.001). All the biomarkers of exposure and most of the biomarkers of potential harm showed no time of sampling (by visit week) effect.     

LDL-apheresis decreases plasma levels and urinary excretion of 8-epi-PGF2alpha

Isoprostanes (IP) generated during free radical catalyzed oxidation injury have been claimed as a reliable indicator of oxidative stress in vivo. In particular, they are formed during LDL-oxidation. Vascular content, plasma levels and urinary excretion of IP were reported to be elevated in hypercholesterolemia. We therefore assessed the values of the IP 8-epi-PGF2alpha in plasma and urine in nine patients (7 males, 2 females) suffering from severe heterozygous hypercholesterolemia before and after LDL-apheresis as well as during the interval. LDL-apheresis caused a significant (P<0.01) drop in 8-epi-PGF2alpha in plasma and urine. The respective values in smokers (n = 4) were significantly (P<0.01) higher as compared to non-smokers. No sex difference was seen. Together with the findings of a parallel decrease in oxidized LDL, these data show a significant benefit of LDL-apheresis reducing in vivo oxidation injury. This benefit may at least partly contribute to the clinical improvement seen in the patients treated.     

Urinary 8-epi-PGF2alpha and its endogenous beta-oxidation products (2,3-dinor and 2,3-dinor-5,6-dihydro) as biomarkers of total body oxidative stress

Although measurements of plasma F2-isoprostanes are established markers of oxidative stress, their quantification only reflects acute non-enzymatic lipid peroxidation. In this study, a new approach is described for the rapid isolation and measurement of urinary 8-epi-PGF2alpha and its endogenous beta-oxidation metabolites (2,3-dinor-8-epi-PGF2alpha and 2,3-dinor-5,6-dihydro-PGF2alpha) for use as index of total body oxidative stress. Isoprostanes were partitioned with ethyl acetate and subsequently purified by chromatography on an aminopropyl (NH2) and silica (Si) cartridge. Final analysis of F2-isoprostanes as trimethylsilyl-ester/pentafluorobenzyl ester derivatives was carried out by stable isotope dilution mass spectrometry. Overall recovery of F2-isoprostanes was 80+/-4%. Inter- and intra-assay coefficients of variation were 5% and 7%, respectively. In a group of healthy humans, the mean excretion rates expressed as nmol/mmol creatinine for 2,3-dinor-8-epi-PGF2alpha, 2,3-dinor-5,6-dihydro-8-epi-PGF2alpha, and 8-epi-PGF2alpha were 5.43+/-1.93, 2.16+/-0.71, and 0.36+/-0.16, respectively. Correlations were obtained between 8-epi-PGF2alpha and 2,3-dinor-8-epi-PGF2alpha or 2,3-dinor-5,6-dihydro-8-epi-PGF2alpha (r=0.998 and r=0.937, respectively). A strong relationship was also seen between 2,3-dinor-8-epi-PGF2 and 2,3-dinor-5,6-dihydro-8-epi-PGF2alpha (r=0.949). The new technique allows for high sample throughput and avoids the need for HPLC and/or other expensive equipment required for the initial sample preparation. Simultaneous analysis of urinary 8-epi-PGF2alpha and its metabolites should provide unique tool in clinical trials exploring the role of oxidant injury in human disease.     

Evaluation of the postprandial effects of a fast-food meal on human plasma F(2)-isoprostane levels

Measurement of the F(2)-isoprostane, 8-epi-PGF(2alpha) is increasingly used as a sensitive and reliable marker of lipid peroxidation in vivo. Because the majority of 8-epi-PGF(2alpha) in plasma is associated with lipoproteins, it is possible that 8-epi-PGF(2alpha) derived from polyunsaturated fatty acid-rich food may become incorporated within these lipoproteins during synthesis and could contribute to the levels detected in plasma. In this study, we evaluated the postprandial effect of a single fast-food meal (McDonald's Big Mac meal, McDonald's Corp., London, England) on plasma total 8-epi-PGF(2alpha) in nine healthy subjects. Blood was collected before and 2 h postprandially. 8-Epi-PGF(2alpha) was measured by immunoaffinity extraction and gas chromatography-mass spectrometry. Fasting plasma 8-epi-PGF(2alpha) (875 +/- 25 pM) increased postprandially (956 +/- 23 pM, p <.05), although no significant change was observed in the normalized concentrations (2. 78 +/- 0.1 vs. 2.95 +/- 0.3 nmol/mmol arachidonic acid). Plasma lipid hydroperoxides, fatty acids, vitamin E, total antioxidant status, cholesterol, and triglycerides were not altered. Plasma glucose increased postmeal (4.4 +/- 0.1 vs. 4.9 +/- 0.1 mM, p <.05). These results indicate that the overall contribution of this lipid-rich meal to plasma 8-epi-PGF(2alpha) and other lipid peroxidation markers was small.     

Eicosanoid generation and responsiveness of human lymphatics in hyperlipoproteinemia

In this work, the oxidation injury in hyperlipoproteinemia (HLP) was determined by measuring the isoprostane 8-epi-prostaglandin (PG) F2alpha in human lymphatics, lymph fluid, plasma, serum and urine. Lymphatics from 6 patients with HLP generated less PGI2 and contained more 8-epi-PGF2alpha as compared to 6 normolipemics without risk factors. Likewise, plasma (29.3 vs 19.7 pg/ml), lymph fluid (137.3 vs 65.3 pg/ml), serum (286.7 vs 204.1 pg/ml) and urinary (360.8 vs 241.0 pg/mg creatinine) values of 8-epi-PGF2alpha in HLP (as compared to normolipemics) were significantly elevated. Lymphatics from HLP showed an enhanced contractile response, less 14C-arachidonic acid conversion to PGI2 and less PGI2-formation upon various stimuli compared to normolipemics of comparable age. These findings indicate that HLP-induced oxidation injury, resulting in an altered (iso-)eicosanoid production and function, may also significantly affect (patho-) physiology of lymphathics.     

Measurement of plasma F2-isoprostanes as an index of lipid peroxidation does not appear to be confounded by diet

F2-isoprostanes (F2-IPs) are formed by the free radical-catalysed oxidation of arachidonic acid. The measurement of F2-IPs, especially 8-epi-PGF2alpha, is recognised as a reliable marker of lipid peroxidation and is currently used as a sensitive index of oxidative stress in vivo. The majority of 8-epi-PGF2alpha present in the circulation occurs in association with lipoproteins which are synthesised in the liver. Since lipoproteins are derived from dietary fatty acids and triglycerides, it is possible that 8-epi-PGF2alpha generated in polyunsaturated fatty acid-rich food (during initial processing/packaging or during meal preparation) may become incorporated within these lipoproteins during synthesis. In view of the growing use of 8-epi-PGF2alpha as a marker of lipid peroxidation in vivo in nutritional or clinical studies, it is therefore important to investigate the possibility that the circulating levels measured could be confounded by the presence of 8-epi-PGF2alpha in food. In this study we evaluated the levels of 8-epi-PGF2alpha present in several popular fast-foods, using a combination of solid phase extraction and gas chromatography-mass spectrometry. Fast-foods were selected to represent meals prepared from vegetable-, chicken-, fish- and meat-derived ingredients. Total (free + esterified) 8-epi-PGF2alpha levels ranged from 0.09 to 0.73 pmol/g (122-644 pmol/mmol arachidonic acid), with the highest levels present in beef-derived meals. Further investigation of hamburgers and cheeseburgers revealed 8-epi-PGF2alpha levels of 1.83 +/- 0.24 and 0.84 +/- 0.03nmol/mmol arachidonic acid, respectively. Lower concentrations of vitamin E were found in the hamburgers. The postprandial contribution to plasma 8-epi-PGF2alpha levels following ingestion of 100 g portions of these fast-foods would therefore be expected to be no greater than the low picomole range, and would be unlikely to influence the normal endogenous levels of 8-epi-PGF2alpha and those produced during oxidative stress.     

Cigarette smoke concentrate increases 8-epi-PGF2alpha and TGFbeta1 secretion in rat mesangial cells

Epidemiological studies have shown that cigarette smoke, an oxidant agent, is a risk factor for the development of diabetic nephropathy (DN), in which pathogenesis transforming growth factor beta(1) (TGFbeta(1)) plays a key role. In our experimental model we exposed mesangial cell cultures to cigarette smoke concentrate (CSC) to study the effect of smoking on the pathogenesis of DN. Thus, we analyzed the effect of CSC on TGFbeta(1) and lipid peroxidation (8-epi-PGF(2alpha)) in rat mesangial cells. Furthermore, since the protein kinase C (PKC) pathway appears to be a key factor for the enhanced production of TGFbeta(1), we also analyzed the effect of the selective PKCbeta inhibitor LY379196 on TGFbeta(1) response to CSC. CSC induced an increase of both TGFbeta(1) and 8-epi-PGF(2) compared to basal conditions (5 mM glucose). The CSC-induced increase in TGFbeta(1) secretion was significantly suppressed by LY379196. These data suggest that smoking could increase TGFbeta(1) production, probably due to oxidative stress and PKCbeta activation. This finding supports the concept that smoking is a risk factor for DN development.     

Salivary isoprostanes indicate increased oxidation injury in periodontitis with additional tobacco abuse

Isoprostanes (IPs) are indicators of in-vivo oxidative stress, and have been successfully used as markers for chronic inflammatory processes. The presence of chronic periodontal disease and cigarette smoking has been individually linked to the development of atherosclerosis, yet data regarding oxidative stress in this context are not available yet. The aim of this study was to evaluate levels of the salivary prostaglandins (PGs) 8-epi-PGF(2alpha), 6-oxo-PGF(1alpha), thromboxane B(2) (TXB(2)) and PGF(2alpha) in association with periodontal disease status with and without additional cigarette smoking. We analyzed saliva samples from 121 adults, (aged 21-73 years, 90 non-smokers, 31 smokers) for levels of 8-epi-PGF(2alpha), 6-oxo-PGF(1alpha), TXB(2) and PGF(2alpha). On the basis of periodontal disease indices the periodontal status of each subject was assessed and outcomes were then correlated with smoking status and laboratory findings. Salivary 8-epi-PGF(2alpha) levels increased with deteriorating plaque index, and were significantly higher (115.5 +/- 23.5 pg/ml) in smoking individuals, when compared to non-smokers (70.2 +/- 20.4 pg/ml, p<0.0001). In addition, smokers showed higher TXB(2) and PGF(2alphas) and lower 6-oxo-PGF(1alpha) levels p<0.0001). Oxidative stress, as reflected by elevated salivary 8-epi-PGF(2alpha) levels, is associated with the extent of periodontal disease and is significantly aggravated by concomitant tobacco abuse. Chronic inflammation and smoking have been individually associated with the development of atherosclerosis. The results of this study indicate that: 1) salivary IPs can reliably assess the degree of oxidative stress, and: 2) smoking and periodontal disease are two modifiable cardiovascular risk factors, able to potentiate each other.     

Enhanced accumulation of the isoprostane, 8-epi-PGF2 alpha,in human aortic and pulmonary valves of patients with coronary heart disease

The aim of the present study was to investigate whether the isoprostane 8-epi-PGF2 alpha differently accumulates in semilunar valves of patients suffering from coronary heart disease (CHD, n = 19) as compared to valves from healthy heart donors (controls, n = 6). Sections from isolated aortic and pulmonary valves were analyzed by semiquantitative immunohistochemistry. The 8-epi-PGF2 alpha-content was determined by using a specific radioimmunoassay. The accumulation of 8-epi-PGF2 alpha in both valves was higher in CHD-patients in comparison to controls (Aortic valves: 36.49 +/- 11.26% vs. 15.78 +/- 3.04%; pulmonary valves: 46.79 +/- 9.80% vs. 14.99 +/- 3.57%). The results from the radioimmunoassay revealed comparable findings in both groups (CHD vs. controls: 395.95 +/- 86.09 vs. 139.50 +/- 47.46 pg/mg protein in the aortic valves and 430.47 +/- 76.30 vs. 147.33 +/- 53.84 pg/mg protein in pulmonary valves). Pulmonary valves seem to be more susceptible to oxidative stress than aortic valves as evidenced by a higher accumulation of 8-epi-PGF2 alpha in CHD patients. Considering the data presented in this study, we suggest that 8-epi-PGF2 alpha is a valuable indicator of oxidative injury in human semilunar valves.     

Determination of urinary 8-epi-prostaglandin F(2alpha) using liquid chromatography-tandem mass spectrometry: increased excretion in diabetics

Liquid chromatography-tandem mass spectrometry (LC/MS-MS) was applied to the quantitative analysis of urinary 8-epi-prostaglandin F(2alpha) (8-epi-PGF(2alpha)) level. 8-Epi-PGF(2alpha) and its internal standard, [(2)H(4)]-8-epi-PGF(2alpha), were extracted from urine by using a solid phase extraction cartridge and loaded to LC/MS-MS in selected reaction monitoring (SRM) mode. The standard curve showed good linearity in the range of 40 pg to 10 ng (r = 0. 997). The accuracy of the added 8-epi-PGF(2alpha) ranged from 96.8 to 104.9% with a mean +/- SD of 99.5+/-2.5%. The average level +/- SD of urinary 8-epi-PGF(2alpha) in 13 healthy volunteers (five women and eight men, 31+/-7.4 years old) was 429.4+/-149.6 pg/mg creatinine. The level of seven patients with noninsulin dependent diabetes mellitus (two women and five men, 40+/-13.6 years old), 630.9+/-275.6 pg/mg creatinine, was statistically higher than that of healthy volunteers (P<0.05). This finding suggested that diabetics are in a highly oxidative condition. This simple and rapid LC/MS-MS method can be used to elucidate the pathophysiological feature of diabetes or for monitoring the curative effect.     

The effects of alcoholism and smoking on platelet eicosanoid production in vitro

Ethanol induces changes in eicosanoid synthesis in blood platelets and brain tissue. Cigarette smoking also causes alterations in eicosanoid formation. This preliminary report examined in vitro platelet sonicate eicosanoid production using 14C-arachidonic acid (14C-AA) and in separate experiments, 14C-PGH2, as substrates. Radiometric thin layer chromatography (TLC) was used to identify the products formed. Eicosanoid product formation in platelet sonicates collected from 28 abstinent male alcoholics were compared to those from 11 male control subjects. All but one of the alcoholics were chronic smokers and all control subjects were non-smokers. All smokers abstained from smoking for 12 h prior to the blood collection to control for any acute effects of cigarette smoke on eicosanoid production. Significant reductions in platelet sonicate production of PGD2 and PGE2 in vitro were observed in alcoholic smokers when 14C-PGH2, but not 14C-AA, was the substrate. These reductions were predicted equally well by two variables, smoking and alcoholism, using several statistical models. This is the first investigation that controlled for the acute effects of smoking and accounted for the potential effects of cigarette smoking on platelet eicosanoid production in alcoholics. Because cigarette smoking is prevalent among alcoholics, future studies on the role of eicosanoids in alcoholism should control for smoking.     

Cardiovascular effects of prostaglandin F(2 alpha) and prostaglandin E(2) in Atlantic cod (Gadus morhua)

Little is known of the cardiovascular functions of prostaglandins in non-mammalian vertebrates. There are indications that prostaglandins may have a function in haemostasis by constricting blood vessels in filament arteries in the fish gill after injury. Our aim was to examine the cardiovascular effect of the prostaglandins F(2 alpha) (PGF(2 alpha)) and E(2) (PGE(2)) with emphasis on branchial circulation. Intra-arterial injections of PGF(2 alpha) (10, 40, 160, 400 nmol kg(-1)) in cod caused a dose-dependent increase in ventral aortic blood pressure, a reduction in cardiac output, and an increase in gill vascular resistance. A contraction of filament arteries was observed with in vivo microscopy only seconds after injection. PGF(2 alpha) may therefore possibly be involved in a haemostatic vasoconstriction. In contrast, the most significant effects of PGE(2) appeared to be on the heart. PGE(2) also reduced dorsal aortic blood pressure.     

Impact of diabetic polyneuropathy and cardiovascular autonomic neuropathy on the excretion of urinary 8-epi-PGF2alpha and its metabolites (2, 3-dinor and 2, 3-dinor-5, 6-dihydro)

The objective of this study was to establish if diabetes in the presence of polyneuropathy (PN) and/or cardiovascular autonomic neuropathy (CAN) is associated with alterations in the amounts of 8-epi-PGF2alpha (IP) and its metabolites including 2, 3-dinor-8-epi-PGF2alpha (dinor-IP) and 2, 3-dinor-5, 6 dihydro-8-epi-PGF2alpha (dinor-dihydro-IP) in urine. Mass spectrometric separation showed that excretion of IP was similar in the PN + /CAN- and PN+/CAN+ groups but higher than in the PN-/CAN- group (n = 103, 22 and 60, respectively; P < 0.05). By contrast, excretion of dinor-IP or dinor-dihydro-IP were similar in the PN-/CAN- and PN+/CAN- groups but higher than in PN+/CAN+ group. Correlations were obtained between IP and dinor-IP or dinor-dihydro-IP (r = 0.30; P < 0.001 and r = 0.31; P < 0.001, respectively). A significant association was also observed between dinor-IP and dinor-dihydro-IP (r = 0.48; P < 0.001). In conclusion, these biomarkers should prove useful in studies evaluating the impact of therapeutic drugs or antioxidant interventions aimed at delaying the onset of diabetic complications.     

Cigarette smoking reduces human salivary eicosanoids.

The effect of cigarette smoking on salivary eicosanoid levels was investigated in 10 smoker and 10 non-smoker volunteers. The smokers consumed an average of 20 cigarettes/day for the past 5 years or longer. The smoking status was validated by salivary cotinine level. Eicosanoids were extracted from saliva with ethanol, and the radioimmunoassay was performed to determine the concentrations of four major eicosanoids, i.e. prostaglandin E2 (PGE2), PGF2 alpha, 6-sulphidopeptide-containing leukotrienes (LTs) and 12-hydroxyeicosatetraenoic acid (12-HETE). The levels of PGE2, PGF2 alpha, and LTs were significantly lower in the saliva of smokers as compared to that of the non-smokers (1.74 +/- 0.32 vs 2.41 +/- 0.64, p = 0.006; 0.36 +/- 0.12 vs 0.54 +/- 0.18, p = 0.04; 2.24 +/- 0.96 vs 4.92 +/- 1.29, p = 0.006; mean +/- SD, ng/ml saliva). No significant differences were found in the levels of 12-HETE between the two groups. The results suggest that cigarette smoking reduces the concentrations of both the cyclooxygenase and 5-lipoxygenase products in saliva.