ORIGINAL ARTICLE

Plasma paraoxonase 1 arylesterase activity in D-galactose-inducedaged rat model: correlation with LDL oxidation and redox status

Dileep Kumar • Syed Ibrahim Rizvi

Received: 2 July 2013 / Accepted: 30 October 2013

� Springer International Publishing Switzerland 2013

Abstract

Objective There is much evidence linking the involve-

ment of oxidative stress in the pathogenesis of aging.

Paraoxonase 1 (PON1) is an HDL-associated antioxidant

enzyme that inhibits the oxidative modification of low-

density lipoproteins (LDL). We have investigated the

changes in plasma PON1 activity, LDL oxidation, radical

scavenging activity and lipid peroxidation in D-galactose-

induced aging rat model and also compared the results with

24-month naturally aged rats.

Method Arylesterase activity of PON1, susceptibility of

LDL for oxidation, plasma radical scavenging activity and

plasma thiobarbituric acid reactive substances (TBARS)

were measured in normal control rats (4-months-old con-

trol rats subjected to D-galactose-induced experimental

aging, and 24-month-old naturally aged rats).

Results There was a significant decrease in plasma PON1

arylesterase activity in both subcutaneous D-galactose-

treated groups and 24-month-old aged rats (P \ 0.05, for

each). TBARS, an oxidative stress marker, was seen to

increase in the experimental groups (P \ 0.01). In both

subcutaneous galactose-treated and naturally aged rats,

there was a significant rise in plasma LDL oxidation

(P \ 0.05, for each). However, radical scavenging activity

was decreased significantly (P \ 0.01) in both groups, as

compared to control.

Conclusions The D-galactose-induced rat model of aging

mimics the naturally aged rat with reference to PON1

arylesterase activity and susceptibility to LDL oxidation.

The results emphasize the importance of PON1 with

respect to aging and its association with redox balance of

the body.

Keywords D-galactose � Aging model � PON1

arylesterase activity � Oxidative stress

Introduction

Aging is impairment of various cellular modulatory func-

tions affecting almost all systems leading to death [1]. It is

an inevitable biological process that eventually causes

many chronic age-associated diseases, including cancer,

cardiovascular diseases and neurodegenerative diseases.

Accumulated evidence has shown that the generation of

free radical or reactive oxygen species (ROS) can lead to

cell and tissue damage, resulting in aging and ultimately

cell death [2].

Scientists in China first reported that sub-acute toxicity

of several carbohydrates, such as D-galactose could induce

neurological impairments in rodents [3, 4]. In most stud-

ies, the mouse or rat aging model was established by

injecting 50–500 mg/kg D-galactose subcutaneously daily

for 6–8 weeks. Both physiologically and pathologically,

the D-galactose-treated animals resemble their aged con-

trol counterparts of 16–24 months [5]. Chronic exposure

of D-galactose has been reported to induce memory loss,

neurodegeneration, oxidative damage and impair neuro-

genesis, a process similar to the natural aging [6, 7]. The

underlying mechanism(s) responsible for D-galactose-

induced aging changes have been explained to be due to

formation of high concentration of advanced glycation

end products (AGE) and also due to increase in osmotic

stress resulting from the reduction of galactose to galac-

titol [8].

D. Kumar � S. I. Rizvi (&)

Department of Biochemistry, University of Allahabad,

Allahabad, UP 211002, India

e-mail: sirizvi@gmail.com

123

Aging Clin Exp Res

DOI 10.1007/s40520-013-0170-2

Paraoxonase 1 (PON1) is an HDL bound enzyme system

which plays a key role in the protection of low-density

lipoproteins (LDL) and HDL from oxidation by hydro-

lyzing activated phospholipids and lipid peroxide products

[9]. PON1 activity is reduced during cardiovascular dis-

eases and cancer [10], as well as during acute infections,

like influenza [11]. Previous researches show that both

LDL and HDL have an increased susceptibility to oxida-

tion with age [12]. Recent interest in the enzyme has arisen

from the idea that PON1 protects LDL and HDL from the

lipid peroxidation [13]. This protection was proposed to be

related to the peroxidase-like activity of PON1 on preex-

isting peroxides and the ability of PON1 to modify the

proportion of oxidation products in oxidized LDL [14].

Despite the association of PON1 activity with the protec-

tion against LDL oxidation, the mechanism by which

PON1 inhibits the oxidation of LDL phospholipids is not

clear. In addition, under oxidative stress conditions, HDL

constitutes a target for oxidative modifications that may

affect their antioxidant properties [15]. It should also be

noted that PON1 activity is strongly dependent on its sta-

bility, which is enhanced in a phospholipid environment

and in association with ApoA1. Nevertheless, there have

been few attempts to define the in vivo conditions for

oxidative inactivation of PON1 and the relationship

between oxidative inactivation of PON1 and its antioxidant

capacity [16]. In a recent study, we have shown a decrease

of PON1 arylesterase activity in humans during aging

which correlates with susceptibility of LDL oxidation [17,

18].

In the present study, we have investigated the PON1

arylesterase activity and susceptibility of low-density

lipoproteins for induced oxidation as a function of age in

rats subjected to D-galactose-induced aging [19, 20]. We

have compared the results with 24-month-old naturally

aged rats.

Material and method

Animal model and study protocol

The experiment was carried out with 21 male wistar rats.

They were housed in a temperature controlled room

(25 ± 5 �C) with 12-h light–dark cycles. All rats were fed

with a normal laboratory diet nutrients rich pellets con-

taining total energy as fat, protein and carbohydrates, and

had free access to drinking water. After 1-week adaptation

period, the animals were divided into three groups of seven

animals each. Group 1: control rats (4 months old), Group

II: rats (4 months old) given daily subcutaneous injections

of D-galactose (100 mg/kg body weight) for 8 weeks,

Group III: naturally aged rats (24 months old).

Collection of blood, isolation of red blood cells

and plasma

During experimental period over, rats were sacrificed under

light anesthesia. Blood samples were collected by cardiac

puncture into 10 U/ml heparin rinsed anticoagulant syrin-

ges, and then red blood cells were pelleted by centrifuga-

tion at 800g for 10 min at 4 �C. After the removal of

plasma (immediately frozen at -80 �C until use for bio-

chemical assays), the aliquots were used for the experi-

ment. All protocols for experiments were approved by the

Animal Care and Ethics Committee of University of

Allahabad.

Plasma lipid profile

Plasma total cholesterol, HDL, and triglycerides were

measured using reagent kits from Erba Diagnostics,

Mannheim, Germany, on Erba Mannheim Chem-7

analyser.

PON1 arylesterase activity

This assay was performed by method developed by Ayub

et al. [21] and subsequently detailed in our earlier papers

[17, 18]. Enzyme activity towards phenyl acetate (arylest-

erase activity) was determined by measuring the initial rate

of substrate hydrolysis in the assay mixture (3 ml) con-

taining 2 mM substrate (phenyl acetate), 2 mM CaCl2 and

10 ll of plasma in 100 mM Tris–HCl (pH 8.0). The

absorbance was monitored for 3 min at 270 nm and the

activity was calculated from E270 = 1,310 per M/cm. The

results are expressed in U/ml, 1 U of arylesterase hydro-

lyses 1 mmol of phenyl acetate per minute.

LDL oxidation

This assay was performed according to the method devel-

oped by Schnitzer et al. [22]. Rate of LDL oxidation was

measured in assay mixture (2 ml) containing 0.72 mM

sodium citrate, 90 lM copper chloride and 40 ll of plasma

in 10 mM phosphate buffer (pH 7.4). Absorbance was

monitored at 245 nm for 3,000 s and graph was plotted for

absorbance versus time. Age-dependent LDL oxidation

was obtained by measuring oxidation at 3,000 s.

Radical scavenging activity of plasma

This assay was performed according to the method as

proposed by Szabo et al. [23]. 100 ll of plasma was added

to 10 mM phosphate buffer (1.9 ml), 0.1 mM DPPH in

methanol (2.0 ml) with a control having 2 ml of 10 mM

phosphate buffer with same amount of DPPH solution. It

Aging Clin Exp Res

123

was kept for incubation for 30 min at 21 �C and centri-

fuged for 5 min at 1,0009g. Absorbance was measured at

517 nm with methanol as a blank. Values were compared

for control (A0) and plasma (A) and percent radical scav-

enging activity (% RSA) was calculated using 100 (A0-A)/

A0. Graph was plotted for different experimental groups

versus % RSA.

Plasma lipid peroxidation

Plasma lipid peroxidation, in terms of thiobarbituric acid

reactive substances (TBARS) was measured according to

the method of Esterbauer and Cheeseman [24], with slight

modification. Plasma (0.2 ml) was added to 1 mL of 10 %

trichloroacetic acid (TCA) and 2 ml of 0.67 % thiobarbi-

turic acid (TBA) boiled for 20 min at 90–100 �C, cooled,

the mixture was centrifuged at 1,000g for 5 min and the

absorbance of supernatant was read at 532 nm. The con-

centration of TBARS in plasma was calculated using

extinction coefficient (e = 31,500) and is expressed as

nmol mL-1 of plasma.

Statistical analysis

All values are expressed as mean ± SD. Statistical analysis

was conducted using Student’s t test and Mann–Whitney

U test using the software PRISM version 5.01. P \ 0.05

was considered as statistically significant. To assess rela-

tionships between parameters, Pearson’s correlation coef-

ficient (r) was derived at 95 % confidence interval by

taking P value \0.05 as significant.

Results

The plasma lipid profile of rats (control, D-galactose trea-

ted, and naturally aged) is given in Table 1. An increase of

30.76 and 35.71 % in cholesterol level is observed in D-

galactose-treated rats and naturally aged rats, respectively,

as compared to control. HDL showed an increase of 13.6

and 18.2 % in D-galactose-treated and naturally aged rats,

respectively, as compared to control. Our results show

decrease in PON1 activity concomitant with increase in

low-density lipoprotein oxidation in D-galactose-induced

aged rats (Figs. 1, 2). The D-galactose-induced aged rats

had significantly (P \ 0.05) lower (37 %) PON1 arylest-

erase activity as compared to age-matched control rats. The

naturally aged rats showed a 40 % decrease in PON1

activity. The aging mimic group animals and 24-month-old

rat groups showed significantly (P \ 0.05) increased ox-

LDL when compared with the normal control group rats

(Fig. 2).

Plasma TBARS levels in D-galactose-induced aged rats

and 24-month-old rats were significantly (P \ 0.01)

Table 1 Lipid profile of experimental rats

Control

(4 months old)

(Mean ± SD)

D-galactose

(Mean ± SD)

Naturally aged

(24 months old)

(Mean ± SD)

Total

cholesterol

(mg/dl)

90 ± 10 130 ± 15 140 ± 20

HDL (mg/dl) 44 ± 5 38 ± 6 36 ± 7

LDL (mg/dl) 42 ± 8 105 ± 15 120 ± 16

Triglyceride

(mg/dl)

85 ± 7 130 ± 13 139 ± 15

Fig. 1 Paraoxonase 1 (arylesterase) activity as a function of age in

different experimental groups including aged groups. *P \ 0.05 as

compared to control. (Control: 4-month-old rats receiving no

treatment/supplementation; D-galactose: rats injected with D-galactose

subcutaneously at 100 mg/kg body weight daily. Naturally aged rats:

24 months old)

Fig. 2 Increasing absorbance of induced LDL oxidation of different

group samples at 245 nm as a function of time measured for 3,000 s.

(only selected group samples are shown). *P \ 0.05 as compared to

control. (Control: 4-month-old rats receiving no treatment/supple-

mentation; D-galactose: rats injected with D-galactose subcutaneously

at 100 mg/kg body weight daily. Naturally aged rats: 24 months old)

Aging Clin Exp Res

123

increased compared with those of the normal control

groups (Fig. 3). The DPPH radical scavenging activity of

plasma in D-galactose-induced aged rats and 24-month-old

rats is shown in Fig. 4. The aging mimetic group showed a

significantly (P \ 0.05) 46 % lower DPPH scavenging

activity as compared to age-matched control rats. The

24-month naturally aged rats had 56 % lower DPPH radical

scavenging activity as compared to control.

The correlations among PON1, LDL oxidation, and

TBARS are shown in Fig. 5. A highly significant

(P \ 0.001) inverse correlation (r = -0.687) is observed

between PON1 and oxidized LDL (Fig. 5a) and PON1 and

TBARS (r = -0.678) (Fig. 5b). A significant (P \ 0.001)

positive correlation (r = 0.742) exists between PON1 and

DPPH scavenging activity of plasma (Fig. 5c).

Discussion

Chemicals can accelerate the process of aging by inducing

changes in various organ systems. D-galactose induces

memory impairment and alters motor skills in experimental

animals [25]. In addition, it alters calcium homeostasis

[26], neurotransmitter synthesis and mitochondrial function

[27]. D-galactose promotes accumulation of free radicals

there by deteriorating neuronal cells [28]. Owing to the

above reasons, D-galactose has been widely employed to

experimentally induce aging in rodents [29]. Alterations in

behavior and neurochemistry are easily replicated by D-

galactose making it a plausible agent to accelerate aging

[30].

PON1 is an HDL-associated antioxidant enzyme that

inhibits LDL cholesterol oxidation in human serum [31,

32]. PON1 confers protection against free radicals by

limiting the oxidation of phospholipids and is known to

lose its activity in the oxidative environment [14, 33]. The

modulation of PON1 by environmental factors has toxi-

cological and clinical consequences because of its protec-

tive role in organophosphate toxicity [34] and in

atherosclerosis [35]. Lifestyle factors such as smoking [36],

stress and exercise [37] also affect on PON1 activity.

The three members of paraoxonase gene family PON1,

PON2 and PON3 are aligned next to each other on the long

arm of mouse chromosome 6 while in human chromosome 7

q21.3-22.1 (38). PON1 polymorphisms (Q192R and L55M)

have been studied in humans; however, no such report is

available for rodents [39]. PON1 and PON3 exert their anti-

atherogenic property by preventing the accumulation of the

lipoperoxides and inhibition of lipid oxidation in LDL [40].

However, several recent studies have suggested that PON1

concentration decreases in some inflammatory and ischemic

diseases, such as diabetes acute pancreatitis, and also losing

its capability during stress and aging condition [17, 18]

which are associated with an increase in oxidative stress [41,

42]. We recently reported the reduction in human PON1

activity and increased susceptibly of LDL oxidation during

aging in humans [17, 18]. The possible role of PON1 in aging

and its effect on longevity has been thoroughly reviewed

with a focus on the relationship between enzyme activity and

genetic polymorphism as well as its capability to counteract

oxidative stress [43].

The results of the current study indicate that PON1

activity was significantly decreased in D-galactose-induced

animal when compared with healthy controls (Fig. 2). The

decrease in PON1 activity (37 %) cannot be attributed to

the observed decrease in HDL levels which is only 13.6 %

(Table 1). In previous studies, reduced serum PON1

activity has been reported to be associated with insulin

resistance [44]. In addition, lower serum PON1 activity has

been associated with increased susceptibility to

Fig. 3 Plasma TBARS content as an oxidative stress marker in

different experimental groups including aged groups. *P \ 0.01 as

compared to control. (Control: 4-month-old rats receiving no

treatment/supplementation; D-galactose: rats injected with D-galactose

subcutaneously at 100 mg/kg body weight daily. Naturally aged rats:

24 months old)

Fig. 4 DPPH radical scavenging activity as a function of age in

different experimental groups including aged groups. *P \ 0.05 as

compared to control. (Control: 4-month-old rats receiving no

treatment/supplementation; D-galactose: rats injected with D-galactose

subcutaneously at 100 mg/kg body weight daily. Naturally aged rats:

24 months old)

Aging Clin Exp Res

123

atherosclerosis, neuropathy, retinopathy and other compli-

cations in diabetic populations compared with healthy

controls [45]. It has been shown that the decrease in

paraoxonase activity may not only be due to development

of oxidative stress conditions with aging but also may be

due to increased susceptibility of HDL oxidation in aged

subjects [17, 18].

Decrease in serum PON1 activity under oxidative stress

has been mostly attributed to changes in the redox status of

the protein free sulfhydryl group which prevent the inhi-

bition of PON1 activity caused by ROS [46]. In addition,

there is some evidence from animal models that PON1 can

protect the HDL particle from oxidation and preserve the

integrity of HDL [47]. In our study, serum PON1 arylest-

erase activity was decreased in the D-galactose-induced

animal model and strongly associated with the severity of

antioxidant potential in terms of radical scavenging assay

(Fig. 4). The importance of maintenance of enzyme –SH

group justifies the importance of plasma redox status as an

important factor in modulation of PON1 activity.

The mechanism of the observed decrease in serum PON1

arylesterase activity in D-galactose-induced animal remains

unclear. This decrease could be related to enhanced lipid

peroxidation in plasma (Fig. 3), since oxidized lipids are

reported to inhibit PON1 activity. Increased inactivation of

PON1 according to increased generation of ROS by D-gal-

actose can explain the decrease in serum PON1 activity [14].

In recent studies, reduced serum PON1 activity has been

reported to be associated with some diseases under oxidative

stress and inflammation conditions [48]. Serum PON1

expression is down-regulated by oxidative stress [49]. In the

present study, MDA levels were increased in the D-galactose

groups. Many clinical investigations have established that

oxidative stress mediated by the ROS plays an important role

in the aging [2]. Ates et al. [50] have demonstrated that

reduced PON1 activity was related to increased MDA levels

in patients with macular degeneration.

These observations suggest that low levels of PON1

may further contribute to the susceptibility of LDL

oxidation in D-galactose inducing group (Fig. 1). Low-

density lipoproteins were found to be more prone to oxi-

dation with increasing age [17, 18]. Minimally oxidized

LDL can be recycled into blood circulation and can be

detected as a serum oxidized LDL because it has a low

affinity to macrophage scavenger receptors. Extensively

oxidized LDL can be taken up by macrophages through the

scavenger receptors. Our results suggest that increase in the

susceptibility of low-density lipoprotein for oxidation is

due to the decrease in serum PON1 arylesterase activity

with D-galactose in a dose-dependent manner and this

prompts us to speculate that decreased PON1 activity

promotes LDL oxidation.

Conclusion

Our findings indicate that lower serum paraoxonase ary-

lesterase and free radical scavenging activities may be

associated with oxidized lipid metabolic disorders and

oxidative damage in D-galactose-induced animal. The D-

galactose-induced rat model of aging mimics the naturally

aged rat with reference to PON1 arylesterase activity and

susceptibility to LDL oxidation. The results emphasize the

importance of PON1 with respect to aging and its associ-

ation with redox balance of the body.

Acknowledgments The authors are grateful to University Grants

Commission, New Delhi for financial support in the form of grant F

37-392/2009 to SIR.

Conflict of interest The authors declare no conflicts of interest.

References

1. Kawakami K, Kadota J, Iida K, Shirai R, Abe K, Kohno S (1999)

Reduced immune function and malnutrition in the elderly. To-

hoku J Exp Med 187:157–171

Fig. 5 a Correlation between PON1/LDL oxidation, b PON1 and TBARS, and c PON1 and DPPH scavenging activity of plasma

Aging Clin Exp Res

123

2. Harman D (2006) Free radical theory of aging: an update:

increasing the functional life span. Ann N Y Acad Sci

1067:10–21

3. Xu FB (1985) Sub-acute toxicity of D-galactose. In: Proceedings

of the Second National Conference on Aging Research. Herbin

China

4. Zhang X, Li WB, Zhang BL (1990) Biochemical changes in D-

galactose induced subacute toxicity and mimetic aging in mice.

Chin J Pharmacol Toxicol 4:309–310

5. Zheng JY, Fu YR, Li M, Gao KS, Zhang XG (2009) Effect of

LTA isolated from bifidobacteria on D-galactose-induced aging.

Exp Gerontol 44:760–765

6. Cui X, Zuo P, Zhang Q, Li X, Hu Y, Long J, Packer L, Liu J

(2006) Chronic systemic D-galactose exposure induces memory

loss, neurodegeneration, and oxidative damage in mice: protec-

tive effects of R-alpha-lipoic acid. J Neurosci Res 84:647–654

7. Zhang Q, Li XK, Cui X, Zuo PP (2009) D-galactose injured

neurogenesis in the hippocampus of adult mice. Neurol Res

27:552–556

8. Yanar K, Aydın S, Cakatay U, Mengi M, Buyukpınarbas N, A-

tukeren P, Sitar ME, Sonmez A, Uslu E (2011) Protein and DNA

oxidation in different anatomic regions of rat brain in a mimetic

ageing model. Basic Clin Pharmacol Toxicol 109(6):423–433

9. Durrington PN, Mackness B, Mackness MI (2001) Paraoxonase

and atherosclerosis. Arterioscler Thromb Vasc Biol 21:473–480

10. Goswami B, Tayal D, Gupta N, Mallika V (2009) Paraoxonase: a

multifaceted biomolecule. Clin Chim Acta 410:1–12

11. Van Lenten BJ, Wagner AC, Nayak DP, Hama S, Navab M,

Fogelman AM (2001) High-density lipoprotein loses its anti-

inflammatory properties during acute influenza infection. Circu-

lation 103:2283–2288

12. Cherki M, Berrougui H, Isabelle M, Cloutier M, Koumbadinga

GA, Khalil A (2007) Effect of PON1 polymorphism on HDL

antioxidant potential is blunted with aging. Exp Gerontol

42:815–824

13. La Du BN (1996) Structural and functional diversity of parao-

xonases. Nat Med 2:1186–1187

14. Nguyen DS, Sok DE (2003) Oxidative inactivation of parao-

xonase 1, an antioxidant protein and its effect on antioxidant

action. Free Radic Res 37:1319–1330

15. Berliner JA, Heinecke JW (1996) The role of oxidized lipopro-

teins in atherogenesis. Free Radic Biol Med 20:707–727

16. Marathe GK, Zimmerman GA, McIntyre TM (2003) Platelet

activating factor acetylhydrolase, and not paraoxonase-1, is the

oxidized phospholipid hydrolase of high density lipoprotein

particles. J Biol Chem 278:3937–3947

17. Mehdi MM, Rizvi SI (2012) Human plasma paraoxonase 1

(PON1) arylesterase activity during aging: correlation with sus-

ceptibility of LDL oxidation. Arch Med Res 43:438–443

18. Mehdi MM, Rizvi SI (2012) Plasma protein hydroperoxides

during aging in humans: correlation with paraoxonase 1 (PON1)

arylesterase activity and plasma total thiols. Arch Med Res

44:136–141

19. Sheng-lang J, Yong-guang Y (2012) In vivo antioxidant activity

of total flavonoids from indocalamus leaves in aging mice caused

by D-galactose. Food Chem Toxicol 50:3814–3818

20. Song X, Mingmin B, Diandong L, Yong LM (1999) Advanced

glycation in D-galactose induced mouse aging model. Mech

Ageing Dev 108:239–251

21. Ayub A, Mackness MI, Arrol S, Mackness B, Patel J, Durrington

PN (1999) Serum paraoxonase after myocardial infarction. Ar-

terioscler Thromb Vasc Biol 19:330–335

22. Schnitzer E, Pinchuk I, Bor A, Fainaru M, Samuni AM, Lich-

tenberg D (1998) Lipid oxidation in unfractionated serum and

plasma. Chem Phys Lipids 92:151–170

23. Szabo MR, Iditoiu C, Chambre D, Lupea AX (2007) Improved

DPPH determination for antioxidant activity spectrophotometric

assay. Chem Paper 61:214–216

24. Esterbauer H, Cheeseman KH (1990) Determination of aldehydic

lipid peroxidation products: malondialdehyde and 4-hydroxy-

nonenal. Methods Enzymol 186:407–413

25. Wei H, Li L, Song Q, Ai H, Chu J, Li W (2005) Behavioural

study of the D-galactose induced aging model in C57BL/6Jmice.

Behav Brain Res 157:245–251

26. Moyer JR Jr, Furtak SC, McGann JP, Brown TH (2009) Aging-

related changes in calcium-binding proteins in rat perirhinal

cortex. Neurobiol Aging 32:1693–1706

27. Kong WJ, Wang Y, Wang Q, Hu YJ, Han YC, Liu J (2006) The

relation between D-galactose injection and mitochondrial DNA

4834 bp deletion mutation. Exp Gerontol 41:628–634

28. Hua X, Lei M, Zhang Y, Ding J, Han Q, Hu G, Xiao M (2007)

Long-term D-galactose injection combined with ovariectomy

serves as a new rodent model for Alzheimer’ disease. Life Sci

80:1897–1905

29. Parameshwaran K, Irwin MH, Steliou K, Pinkert CA (2010) D-

galactose effectiveness in modeling aging and therapeutic anti-

oxidant treatment in mice. Rejuvenation Res 13:729–735

30. Lei M, Hua X, Xiao M, Han Q, Hu G (2008) Impairments of

astrocytes are involved in the D-galactose induced brain aging.

Biochem Biophys Res Commun 369:1082–1087

31. Santanam N, Parthasarathy S (2007) Aspirin is a substrate for

paraoxonase-like activity: implications in atherosclerosis. Ath-

erosclerosis 191:272–275

32. Tsuzura S, Ikeda Y, Suehiro T, Ota K, Osaki F, Arii K, Kumon Y,

Hashimoto K (2004) Correlation of plasma oxidized low-density

lipoprotein levels to vascular complications and human serum

paraoxonase in patients with type 2 diabetes. Metabolism

53:297–302

33. Jaouad L, Milochevitch C, Khalil A (2003) PON1 paraoxonase

activity is reduced during HDL oxidation and is an indicator of

HDL antioxidant capacity. Free Radic Res 37:77–83

34. Li WF, Furlong CE, Costa LG (1995) Paraoxonase protects

against chlorpyrifos toxicity in mice. Toxicol Lett 76:219–226

35. Costa LG, Vitalone A, Cole TB, Furlong CE (2005) Modulation

of paraoxonase (PON1) activity. Biochem Pharmacol 69:541–550

36. Van Himbergen TM, van der Schouw YT, Voorbij HA, van Tits

LJ, Stalenhoef AF, Peeters PH, Roest M (2008) Paraoxonase

(PON1) and the risk for coronary heart disease and myocardial

infarction in a general population of Dutch women. Atheroscle-

rosis 199:408–414

37. Ozturk H, Gungor M, Yigit S, Tacyildiz H, Basinoglu F, Koldas

M (2009) Effect of exercise on the paraoxonase activity. Clin

Biochem 42:343–346

38. La Du BN, Aviram M, Billecke S, Navab M, Primo-Parmo S,

Sorenson RC, Standiford TJ (1999) On the physiological role(s) of

the paraoxonases. Chem Biol Interact 14(119–120):379–388

39. Costa LG, Giordano G, Cole TB, Marsillach J, Furlong CE

(2013) Paraoxonase 1 (PON1) as a genetic determinant of sus-

ceptibility to organophosphate toxicity. Toxicol 10(307):115–122

40. Tavori H, Aviram M, Khatib S, Musa R, Nitecki S, Hoffman A,

Vaya J (2009) Human carotid atherosclerotic plaque increases

oxidative state of macrophages and low-density lipoproteins,

whereas paraoxonase 1 (PON1) decreases such atherogenic

effects. Free Radic Biol Med 46:607–615

41. Mackness B, Durrington PN, Boulton AJM, Hine D, Mackness

MI (2002) Serum paraoxonase activity in patients with type 1

diabetes compared to healthy controls. Eur J Clin Invest

32:259–264

42. Unal E, Uzun H, Kusaslan R, Dogan M, Genc H, Gunes P, Titiz I

(2005) Serum paraoxonase (a high-density lipoprotein-associated

Aging Clin Exp Res

123

lipophilic antioxidant) activity and lipid profile in experimental

acute pancreatitis. Pancreas 31:84–87

43. Marchegiani F, Mara M, Oliveri F, Cardelli M, James RW, Bo-

emi M, Franceschi C (2008) Paraoxonase 1: genetics and activ-

ities during aging. Rejuvenation Res 11:113–127

44. Polat D, Ezgi D, Ahmet B, Hakan Y (2006) Decreased serum

paraoxonase 1 (PON1) activity: an additional risk factor for

atherosclerotic heart disease in patients with PCOS? Hum Reprod

21:104–108

45. Caroline AA, Michael IM, Sudhesh K, Andrew JB, Paul ND

(1995) Serum paraoxonase activity, concentration, and phenotype

distribution in diabetes mellitus and its relationship to serum

lipids and lipoproteins. Arterioscler Thromb Vasc Biol

15:1812–1818

46. Jaouad L, de Guise C, Berrougui H, Cloutier M, Isabelle M,

Fulop T, Payette H, Khalil A (2006) Age-related decrease in

high-density lipoproteins antioxidant activity is due to an alter-

ation in the PON1’s free sulfhydryl groups. Atherosclerosis

185:191–200

47. Aviram M, Rosenblat M, Bisgaier CL, Newton RS, Primo-Parmo

SL, La Du BN (1998) Paraoxonase inhibits high-density lipo-

protein oxidation and preserves its functions. A possible peroxi-

dative role for paraoxonase. J Clin Invest 101:1581–1590

48. Mackness B, Durrington PN, Mackness MI (1998) Review

human serum paraoxonase. Gen Pharmacol 31:329–336

49. Rozenberg O, Aviram M (2006) S-Glutathionylation regulates

HDL associated paraoxonase 1 (PON1) activity. Biochem Bio-

phys Res Commun 351:492–498

50. Ates O, Azizi S, Alp HH, Kiziltunc A, Kocer I, Baykal O (2009)

Decreased serum paraoxonase 1 activity and increased serum

homocysteine and malondialdehyde levels in age-related macular

degeneration. Tohoku J Exp Med 217:17–22

Aging Clin Exp Res

123