Paraoxonase and arylesterase activities in fibromyalgia

We aimed to evaluate the association of serum paraoxonase and arylesterase activities and oxidative/antioxidative status in patients with fibromyalgia. Forty-two patients with fibromyalgia and 53 healthy controls were included in the study. Serum paraoxonase and arylesterase activities were measured spectrophotometrically. Oxidative and antioxidative status were evaluated by measuring serum lipid hydroperoxide (LOOH) levels, total antioxidant status (TAS) and free sulfhydryl groups (-SH = total thiol). Lipid parameters were determined by routine laboratory methods. Serum paraoxonase and arylesterase activities, and TAS were lower in patients with fibromyalgia than in controls (P < 0.001, for all), and the -SH level was also lower in the patient group (P = 0.03). LOOH levels were higher in the patient group than in controls (P = 0.01). Our results suggest that patients with fibromyalgia were exposed to oxidative stress, and paraoxonase and arylesterase activities were decreased in these patients. Patients with fibromyalgia might be prone to development of atherosclerosis with reduced paraoxonase and arylesterase activities.     

Serum paraoxonase and arylesterase activities in patients with chronic otitis media

Objectives: Paraoxonase-1 (PON1) prevents oxidative stress by inhibiting the oxidation of cell membrane lipids by the reactive oxygen species that form during acute and chronic inflammation. The aim of this study was to investigate serum PON1 activity and oxidative stress in patients with chronic otitis media (COM).

Methods: Fifty consecutive patients with COM and 55 controls were enrolled in the present study. The patients were divided into two groups according to the presence of cholesteatoma. The serum PON1 arylesterase activities and lipid hydroperoxide (LOOH) levels were determined.

Results: Serum paraoxonase and arylesterase activities were significantly lower in the COM patients than in the controls (P < 0.001 for all comparisons), whereas the LOOH levels were significantly higher (P < 0.001).

Discussion: These results indicated that a lower level of PON1 activity was associated with an oxidant–antioxidant imbalance. In addition, decreased PON1 activity may play an important role in the pathophysiology of COM.     

Lipid peroxidation markers in children with anxiety disorders and their diagnostic implications

Abstract

Objective

Numerous factors, including genetic, neurobiological, neurochemical, and psychological factors, are thought to be involved in the development of anxiety disorders. The latest findings show that the pathophysiology of anxiety disorders might be associated with oxidative stress and lipid peroxidation; however, no studies have so far investigated lipid peroxidation markers in children with anxiety disorders. Serum levels of lipid hydroperoxide (LOOH) are a reliable marker of lipid peroxidation. Paraoxonase and arylesterase are two enzymes that protect against such peroxidation, and might also be diagnostic markers. In this study, we investigated whether there are associations between anxiety disorders and lipid peroxidation markers in children, and assessed the diagnostic performance of these markers.

Methods

The study group consisted of 37 patients (children and adolescents) with anxiety disorders. A control group, matched for age and gender, was composed of 36 healthy subjects. Venous blood samples were collected, and LOOH levels and paraoxonase and arylesterase activity were measured.

Results

LOOH levels were significantly higher in the anxiety disorders group than in the control group. There were no significant differences in paraoxonase or arylesterase activities between the patient and the control groups.

Discussion

Lipid peroxidation or oxidative damage might play a role in the aetiopathogenesis of anxiety disorders. LOOH may be a potential biological marker for anxiety disorders in children.     

Activity of paraoxonase 1 and lipid profile in healthy children

Paraoxonase 1 (PON1) seems to have a relevant role in detoxifying processes and in atherosclerosis. The aim of this study was to determine PON1 activity, the total antioxidant capacity, as well as entire lipid profile in children for screening of possible risk of atherosclerosis development. Serum PON1 arylesterase/paraoxonase activities were determined spectrophotometrically. The total antioxidant capacity of the serum was measured by TEAC method. Parameters of lipid profile were analyzed by routine laboratory methods. It has been shown that PON1 arylesterase/ paraoxonase activities were very similar to values found in adults. In children, no significant correlation between PON1 arylesterase activity and HDL was observed. PON1 paraoxonase activity correlated only with atherogenic index. PON1 arylesterase activity was significantly higher in girls than in boys. The antioxidant capacity was inversely related to the body mass index. In this study, PON1 activity was determined in healthy children aged 11 to 12 years and we found a similarity in PON1 activities of children and adults. Moreover, the results of our study support the hypothesis that higher body weight of children may contribute to a greater risk for development of atherosclerosis in which oxidative stress plays a role.     

Oxidative stress and serum paraoxonase activity in experimental hypothyroidism: effect of vitamin E supplementation

Thyroid hormones are associated with the oxidative and antioxidative status of the organism. Since data on the oxidative status of hypothyroidism are limited and controversial, we investigated the oxidant and antioxidant status and serum paraoxonase/arylesterase activities in propylthiouracil-induced hypothyroidism and examined the effect of vitamin E supplementation on this experimental model. Forty male Sprague Dawley rats were randomly divided into four groups (group 1, control; group 2, control + vitamin E; group 3, propylthiouracil; group 4, propylthiouracil + vitamin E). Plasma, red blood cell, liver, heart and skeletal muscle malondialdehyde levels were increased in the propylthiouracil-treated group compared with the control rats and were decreased in propylthiouracil + vitamin E group compared with the propylthiouracil-treated group. Vitamin E supplementation also significantly increased liver and kidney reduced glutathione levels in propylthiouracil treated animals. Serum paraoxonase and arylesterase activities were decreased in propylthiouracil treated group and vitamin E supplementation caused significant increase in serum paraoxonase activity compared with the propylthiouracil-treated rats. These findings suggest that hypothyroidism is accompanied with increased oxidative stress and vitamin E supplementation exerts beneficial effects on this situation.     

Serum Paraoxonase and Arylesterase Activities and Oxidative Stress Levels in Patients with SSRI Intoxication

Oxidative stress is a critical route of damage in various psychological stress-induced disorders, such as depression. Paraoxonase-1 (PON1) plays an important role as an endogenous free-radical scavenging molecule. The aim of this study was to evaluate the influence of serum PON1 activity and oxidative stress in patients with selective serotonin reuptake inhibitor (SSRI) intoxication. A total of 11 patients with SSRI intoxication and 20 healthy controls were enrolled. The serum total antioxidant capacity (TAC) and malondialdehyde (MDA) levels, as well as the paraoxonase and arylesterase activities, were measured spectrophotometrically. The serum TAC levels and the paraoxonase and arylesterase activities were significantly lower (for all, p < 0.001), whereas the serum MDA levels were significantly higher in the patients with SSRI intoxication than in the controls (p < 0.001). These results indicated that decreased PON1 activity and increased oxidative stress represent alternative mechanisms in SSRI toxicity. More studies are needed to elucidate the role of PON1 activity in the etiology of SSRI intoxication.     

Paraoxonase and arylesterase levels in autoimmune thyroid diseases

Objective: The aim of this study was to evaluate serum paraoxonase-1 (PON1) activity and its association with oxidative stress in autoimmune thyroid disease (AITD).

Methods: A total of 50 patients with AITD, including 25 with Hashimoto's thyroiditis and 25 with Graves’ disease were enrolled. The control group comprised 27 healthy subjects. Blood samples were obtained in the euthyroid period and 3 months after initiation of medical treatment. Serum samples from patients with AITD and the healthy control group were analyzed for basal PON1, salt-stimulated PON1, and arylesterase (ARE) activities, along with lipid hydroperoxide (LOOH) and total free sulfhydryl (–SH) levels.

Results: Serum PON1 activities and –SH levels were significantly lower (P?<?0.001, for each), whereas LOOH levels were significantly higher (P?<?0.001, for each) in patients with AITD, compared to the control group. We observed no significant differences in ARE levels between the patient and healthy control groups (P?>?0.05). PON1 activity was positively correlated with –SH (r?=?0.522, P?<?0.001) and negatively correlated with LOOH (r?=??0.487, P?<?0.001). PON1 phenotype distribution of the subjects was not significantly different among the three groups (P?=?0.961).

Conclusions: Serum PON1 activity is decreased in patients with AITD, and correlated positively with –SH, a well-known antioxidant, and negatively with LOOH, an index of lipid oxidation.     

Serum lipid profile paraoxonase and arylesterase activities in psoriasis

Psoriasis is a common chronic and recurrent inflammatory skin disease with unknown etiology that has been associated with abnormal plasma lipid metabolism and oxidative stress. There are controversial results in the previous studies investigating oxidant/antioxidant systems in psoriasis. The aim of this work was to evaluate dyslipidemia, oxidative stress, total antioxidant capacity and serum paraoxonase (PON1) and arylesterase (ARE) activities in psoriasis, and to look for a correlation between these parameters and lesion percentage in psoriasis. Thirty psoriatic patients and twenty three sex‐ and agematched healthy volunteers were included in the study. From blood samples, lipid profile, malondialdehyde (MDA) levels, total antioxidant capacity (TAO), serum PON1 and ARE activities were determined. No significant differences between the patients and controls were found in terms of total cholesterol, triacylglycerol (TAG), HDL‐cholesterol, LDL‐cholesterol, VLDL‐cholesterol, MDA and TAO levels. Serum PON1 and sodium‐stimulated PON1 activities (p < 0.05) and ARE activity (p < 0.01) were found significantly higher in the patients than in the controls. There was not any significant correlation between lesion percentage and the parameters studied. Copyright © 2009 John Wiley & Sons, Ltd.     

Paraoxonase 1 (PON1) and its relationship to lipid variables, age and gender in healthy volunteers

Recent studies implied that low-density lipoprotein (LDL) modified predominantly by oxidation or glycation, significantly contributes to the formation of atherosclerotic lesions. In contrast to oxidized LDL (ox-LDL), high-density lipoprotein (HDL) is able to prevent accumulation of ox-LDL in arterial walls. This antiatherogenic property of HDL is attributed in part to several enzymes associated with the lipoprotein, including HDL-associated paraoxonase 1 (PON1). In this study we analyzed PON1 arylesterase/paraoxonase activities in relation to serum lipid profile, gender and age in thirty clinically healthy Slovak volunteers. Our results showed that PON1 arylesterase and paraoxonase activities were lower in citrated plasma than in serum by 16.6% and 27.3%, respectively. Among serum lipoproteins, only HDL-cholesterol level showed significant positive correlation with PON1 arylesterase activity (p = 0.042). Likewise, we found a significant relationship between atherogenic index (AI = total cholesterol/HDL-cholesterol) and PON1 arylesterase activity (p = 0.023). No significant correlation could be demonstrated between PON1 paraoxonase activity and serum lipid profile, age or gender. Furthermore, it was found that PON1 paraoxonase/arylesterase activities were higher in women compared with both investigated activities in men, but these differences were not statistically significant. These results confirmed a positive correlation between HDL-cholesterol and PON1 arylesterase activity. Moreover, it was found out that PON1 paraoxonase activity is not influenced either by gender or by age. PON1 arylesterase activity was however affected by gender to a limited extent.     

Activity of paraoxonase 1 (PON1) and its relationship to markers of lipoprotein oxidation in healthy Slovaks

Low-density lipoproteins (LDLs), when modified by free radicals derived from artery wall cells, induce atherosclerosis. In contrast to oxidized LDL (ox-LDL), high-density lipoproteins (HDLs) are able to prevent atherosclerosis through a protein with antioxidant properties, paraoxonase 1 (PON1). The purpose of this study was to explore the association between the activity of HDL-associated PON1 and circulating ox-LDL as well as to investigate the relationship between ox-LDL and parameters of lipid profile in thirty Slovaks aged 21-73 years because recent studies have presented controversial results concerning PON1 and its role in LDL oxidation. For determination of circulating ox-LDL sandwich ELISA was used and other lipid parameters were determined by routine laboratory analyses. PON1 activities were assayed by two synthetic substrates - paraoxon and phenyl acetate. Lipid peroxides were determined spectrophotometrically. Of the lipid parameters examined, ox-LDL level correlated positively with total (P < 0.0001) and LDL-cholesterol (P < 0.001). Triacylglycerols (TAG) (P < 0.001), lipid peroxides (P < 0.01) and atherogenic index (AI = total cholesterol/HDL) (P < 0.0001) were also strongly correlated with ox-LDL. No inverse relationships were observed between ox-LDL and HDL-cholesterol or arylesterase/paraoxonase activities of PON1. Furthermore, it was found that ox-LDL (P < 0.01) and lipid peroxides (P < 0.05) were significantly higher in men than in women. PON1 arylesterase activity was marginally affected by sex. The results of this study suggest that the anti-atherogenic properties of HDLs are not directly related to their total concentration and that PON1 activity determined towards synthetic compounds (paraoxon and phenyl acetate) reflects no association with markers of oxidative stress. Furthermore, it follows from our results that men are more susceptible to developing atherosclerosis compared to women.     

Serum prolidase activity and oxidative–antioxidative status in patients with developmental dysplasia of the hip and its relationship with radiographic severity

Background: We aimed to investigate serum prolidase activity and to investigate its association with oxidative–antioxidative status in patients with developmental dysplasia of the hip (DDH).

Methods: Oxidative status parameters, including lipid hydroperoxide (LOOH), total oxidant status (TOS), and the oxidative stress index (OSI), and antioxidative status parameters, free sulfhydryl groups (Total –SH), and total antioxidative capacity (TAC), as well as serum prolidase activity were assessed in patients with DDH (n?=?93), and in healthy controls (n?=?82). The severity of dysplasia was evaluated according to the Tonnis grading system.

Results: Serum prolidase activity and the oxidant parameters (LOOH, TOS, and OSI) were significantly higher and the antioxidant parameters (Total –SH and TAC) were significantly lower in patients with DDH compared to the controls (P?P?P?Conclusion: Increased levels of serum prolidase activity, LOOH, TOS, and OSI, and decreased levels of total –SH and TAC, may be associated with DDH, and these parameters may be useful adjunctive tools to assess the severity of DDH.     

Serum paraoxonase 1 activity and malondialdehyde levels in patients with ulcerative colitis

This study was designed to evaluate the oxidative and antioxidative status in patients with ulcerative colitis by detecting antioxidant enzyme paraoxonase 1 activity together with the level of a well-known marker of oxidative stress, malondialdehyde. Serum paraoxonase 1 activity and malondialdehyde levels were analysed in 30 patients with ulcerative colitis and 30 controls using a spectrophotometric method; correlation analysis was made between these variables. Serum malondialdehyde levels were higher in the ulcerative colitis group (median: 2.5, range: 0.5-9.4 nmol ml(-1)) than among the controls (median:1.1, range: 0.5-2.3 nmol ml(-1); p < 0.001) whereas paraoxonase 1 activities were lower in the ulcerative colitis group (median: 158.4, range: 61.6-264.1 U l(-1)) than in the control group (median: 233.3, range: 114.4-431.0 U l(-1); p < 0.001). There was no correlation between serum malondialdehyde level, paraoxonase 1 activity and disease activity. (1) Increased reactive oxygen metabolites levels in ulcerative colitis may result in a pro-oxidation environment, which in turn could result in decreased antioxidant paraoxonase 1 activity and increased malondialdehyde levels, (2) increased cytokines may be a possible cause of decreased paraoxonase 1 activity and (3) decreased serum paraoxonase 1 activity may be a part of an inflammatory response.     

Levels of paraoxonase and arylesterase activities and malondialdehyde in workers exposed to ionizing radiation

We examined levels of malondialdehyde (MDA) (an end-product of lipid peroxidation) and paraoxonase (PON1) (an antioxidant enzyme) activity and PON1 phenotypes in people who were exposed to ionizing radiation for different time periods and doses. A total of 78 individuals (mean age 34 +/- 7 years) were included in the study. Fifty-one of them were radiology workers whereas the control group was composed of 27 healthy volunteers who had never worked in a radiology-related job. Paraoxon was used as substrate for measurement of PON1 activity levels (basal and NaCl-stimulated). Phenylacetate was used as substrate for measurement of arylesterase activity levels. Cumulative levels of serum NaCl-stimulated PON1/arylesterase activities were utilized for phenotypic differentiation. In radiology workers, three different phenotypes were determined based on paraoxonase/arylesterase ratio. The ratios were 1.09 +/- 0.30 for AA (homozygote low activity); 2.91 +/- 1.07 for AB (heterozygote activity) and 4.97 +/- 1.21 for BB (homozygote high activity). There was a statistically meaningful negative correlation between serum MDA levels and PON1 activity levels in all phenotypes (p < 0.05). PON1 activity levels were found to be 25-35% lower in people who were exposed to long-term ( > 5 years) radiation compared to controls. There was no statistically significant correlation between serum arylesterase activity and MDA levels in these subjects (r = -0.185, p > 0.05). PON1 activity levels were decreased whereas serum MDA levels were increased in individuals exposed to radiation for a long period. PON phenotypes of people employed in jobs which expose them to radiation should be determined and based on these findings they should be advised to avoid risk factors inducing oxidative stress, such as smoking, and to consume foods rich in vitamins and trace elements to increase their antioxidant capacity.     

VLDL triglycerides inhibit HDL-associated paraoxonase 1 (PON1) activity: in vitro and in vivo studies

We analyzed, for the first time, both in vitro and in vivo, the effect of very low density lipoprotein (VLDL), or of pure triglycerides, on high-density lipoprotein (HDL)-associated paraoxonase1 (PON1) catalytic activities. Incubation of serum or HDL from healthy subjects with VLDL (0-330 μg protein/mL) significantly decreased serum PON1 lactonase or arylesterase activities by up to 11% or 24%, and HDL-associated PON1 lactonase or arylesterase activities by up to 32% or 46%, respectively, in a VLDL dose-dependent manner. VLDL (0-660μg protein/mL) also inhibited recombinant PON1 (rePON1) lactonase or arylesterase activities by up to 20% or 42%, respectively. Similar inhibitory effect was noted upon rePON1 incubation with pure triglyceride emulsion. Bezafibrate therapy to three hypertriglyceridemic patients (400 mg/day, for one month) significantly decreased serum triglyceride concentration by 67%, and increased serum HDL cholesterol levels by 48%. PON1 arylesterase or paraoxonase activities in the patients' HDL fractions after drug therapy were significantly increased by 86-88%, as compared to PON1 activities before treatment. Similarly, HDL-PON1 protein levels significantly increased after bezafibrate therapy. Finally, bezafibrate therapy improved HDL biological activity, as HDL obtained after drug therapy showed increased ability to induce cholesterol efflux from J774A.1 macrophages, by 19%, as compared to HDL derived before therapy. We thus conclude that VLDL triglycerides inhibit PON1 catalytic activities, and bezafibrate therapy significantly improved HDL-PON1 catalytic and biological activities. ? 2012 International Union of Biochemistry and Molecular Biology, Inc.     

Paraoxonase-1 activity in patients with hyperemesis gravidarum

There is increasing evidence that oxidative stress may play a role in the pathophysiology of hyperemesis gravidarum. Serum paraoxonase-1 (PON-1) is a high density lipoprotein (HDL)-associated enzyme that prevents oxidative modification of low density lipoprotein. The aim of the study was to measure the serum levels of PON-1 activity in women with hyperemesis gravidarum. Thirty-four women with hyperemesis gravidarum and 31 healthy pregnant women were enrolled in the study. Serum PON-1 activity was measured spectrophotometrically. Lipid hydroperoxide (LOOH) levels were measured by iodometric assay. PON-1 activity was significantly lower and LOOH levels were significantly higher in pregnant women with hyperemesis gravidarum than in healthy pregnant women (P < 0.0001, for all). There were significant correlations between PON-1 and LOOH, triglyceride, total cholesterol, HDL, low density lipoprotein (LDL) and high sensitive C-reactive protein (HSCRP; P < 0.0001, for all). By using multiple regression analysis LDL, HDL, HSCRP and LOOH were independent determinants of serum PON-1 activity in the study. Decreased PON-1 activity might be related to increased oxidative stress and inflammation in pregnant women with hyperemesis gravidarum. Subjects with hyperemesis gravidarum might be more prone to the development of atherogenesis due to low serum PON-1 activity.     

A sandwich enzyme-linked immunosorbent assay for human serum paraoxonase concentration

Serum paraoxonase (PON) is associated with plasma high density lipoproteins, and prevents the oxidative modification of low density lipoproteins. We have developed a sensitive sandwich enzyme-linked immunosorbent assay (ELISA), using two monoclonal antibodies against PON, to measure serum PON concentration. The concentration of PON in healthy Japanese subjects was 59.3 +/- 1.3 microgram/mL (mean +/- SEM; n = 87). Serum PON concentrations in relation to the PON 192 genetic polymorphism were: 69.5 +/- 2.9 microgram/mL in the QQ genotype; 63.0 +/- 1.9 microgram/mL in the QR genotype; and 52.8 +/- 1.7 microgram/mL in the RR genotype. Concentrations were significantly lower in the RR than in the QQ genotype (P < 0.01). Serum paraoxonase specific activity was higher in RR than in QQ subjects (18.6 +/- 0.40 vs. 2. 56 +/- 0.05 nmol/min/microgram, P < 0.01), but arylesterase specific activity was unrelated to genotype. PON concentration was positively associated (P < 0.001) with both serum arylesterase activity and, after adjusting for the effect of the position 192 polymorphism, with serum paraoxonase activity. Subjects with angiographically verified coronary heart disease had significantly lower PON concentrations than the healthy controls (52.0 +/- 2.3 microgram/mL; n = 35, P < 0.01). This association was independent of the position 192 genotype. Our new ELISA should be of value for epidemiologic and clinical studies of serum PON concentration. immunosorbent assay for human serum paraoxonase concentration.     

Paraoxonase-1 activity in patients with hyperemesis gravidarum

Abstract

There is increasing evidence that oxidative stress may play a role in the pathophysiology of hyperemesis gravidarum. Serum paraoxonase-1 (PON-1) is a high density lipoprotein (HDL)-associated enzyme that prevents oxidative modification of low density lipoprotein. The aim of the study was to measure the serum levels of PON-1 activity in women with hyperemesis gravidarum. Thirty-four women with hyperemesis gravidarum and 31 healthy pregnant women were enrolled in the study. Serum PON-1 activity was measured spectrophotometrically. Lipid hydroperoxide (LOOH) levels were measured by iodometric assay. PON-1 activity was significantly lower and LOOH levels were significantly higher in pregnant women with hyperemesis gravidarum than in healthy pregnant women (P < 0.0001, for all). There were significant correlations between PON-1 and LOOH, triglyceride, total cholesterol, HDL, low density lipoprotein (LDL) and high sensitive C-reactive protein (HSCRP; P < 0.0001, for all). By using multiple regression analysis LDL, HDL, HSCRP and LOOH were independent determinants of serum PON-1 activity in the study. Decreased PON-1 activity might be related to increased oxidative stress and inflammation in pregnant women with hyperemesis gravidarum. Subjects with hyperemesis gravidarum might be more prone to the development of atherogenesis due to low serum PON-1 activity.     

Indications that paraoxonase-1 contributes to plasma high density lipoprotein levels in familial hypercholesterolemia

HDL-associated paraoxonase type 1 (PON1) can protect LDL and HDL against oxidative modification in vitro and therefore may protect against cardiovascular disease. We investigated the effects of PON1 levels, activity, and genetic variation on high density lipoprotein-cholesterol (HDL-C) levels, circulating oxidized LDL (OxLDL), subclinical inflammation [high-sensitive C-reactive protein (Hs-CRP)], and carotid atherosclerosis. PON1 genotypes (L55M, Q192R, -107C/T, -162A/G, -824G/A, and -907G/C) were determined in 302 patients with familial hypercholesterolemia. PON1 activity was monitored by the hydrolysis rate of paraoxon, diazoxon, and phenyl acetate. PON1 levels, OxLDL, and Hs-CRP were determined using an immunoassay. The genetic variants of PON1 that were associated with high levels and activity of the enzyme were associated with higher HDL-C levels (P values for trend: 0.008, 0.020, 0.042, and 0.037 for L55M, Q192R, -107C/T, and -907G/C, respectively). In addition to the PON1 genotype, there was also a positive correlation between PON1 levels and activity and HDL-C (PON1 levels: r = 0.37, P < 0.001; paraoxonase activity: r = 0.23, P = 0.01; diazoxonase activity: r = 0.29, P < 0.001; arylesterase activity: r = 0.19, P = 0.03). Our observations support the hypothesis that both PON1 levels and activity preserve HDL-C in plasma.     

Effects of cold stress on serum lipids, lipoproteins, and the activity of lecithin:cholesterol acyltransferase in rabbits

Effects of prolonged stress on lipid metabolism factors were studied for 9 weeks using four groups of young New Zealand rabbits. Two groups (A,B) were rendered atherosclerotic by administering 1% (w/w) cholesterol. One group (C) was subjected to cold stress together with one of the atherosclerotic groups (B); one group was used as control (N). At the end of treatment serum total cholesterol and total lipids of A and B increased significantly, while in stress group (C) a significant decrease was observed. HDL-C levels were reduced in all experimental groups. Triglycerides did not change in A, while they were reduced in both stress groups (C,B). Serum lecithin:cholesterol acyltransferase (LCAT) activity levels of B and C were decreased. Lipoprotein electrophoresis patterns showed a significant redistribution of percentage values in all experimental groups: %LDL-C increased and %VLDL-C decreased in all groups, %HDL-C declined in A and B and did not change in C. The combination of stress and atherosclerosis in rabbits elicits far greater alterations in lipid and lipoprotein profiles than stress or atherosclerosis alone. A stress and atherosclerotic diet combination may be a hazardous one in relation to CHD and atherosclerosis.     

Ulva rigida improves carbohydrate metabolism, hyperlipidemia and oxidative stress in streptozotocin-induced diabetic rats

This study was designed to investigate the effects of Ulva rigida, one of the green algae, on the lipid profile and oxidative–antioxidative systems in streptozotocin‐induced diabetic rats. Forty Wistar rats randomly divided into four groups: control (C), control + U. rigida extract (C + URE), diabetes (D) and diabetes + U. rigida extract (D + URE). U. rigida (2%) was administered in drinking water for 5 weeks after the induction of diabetes. U. rigida reduced the blood glucose, serum total cholesterol, triglyceride levels and plasma and tissue malondialdehyde (MDA) levels in the D + URE group. Insulin levels were significantly higher in the D + URE than those of the D group. Serum total cholesterol and tissue MDA levels were reduced in the C + URE group. Whole blood glutathione peroxidase and erythrocyte superoxide dismutase activities were higher in the D and C + URE groups compared with the C group. Paraoxonase and arylesterase activities were lower in the D group while U. rigida increased paraoxonase activities in C + URE and D + URE groups. This is the first study which showed U. rigida has antidiabetic and antihyperlipidemic effects and improves oxidative stress in diabetic rats. We conclude that U. rigida might have a potential use as a protective and/or therapeutic agent in diabetes mellitus. Copyright © 2011 John Wiley & Sons, Ltd.