Serum paraoxonase and arylesterase activity and oxidative status in patients with multiple sclerosis

Oxidative Stress Markers in Multiple Sclerosis

The pathogenesis of multiple sclerosis (MS) is not completely understood, but genetic factors, autoimmunity, inflammation, demyelination, and neurodegeneration seem to play a significant role. Data from analyses of central nervous system autopsy material from patients diagnosed with multiple sclerosis, as well as from studies in the main experimental model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), suggest the possibility of a role of oxidative stress as well. In this narrative review, we summarize the main data from studies reported on oxidative stress markers in patients diagnosed with MS and in experimental models of MS (mainly EAE), and case-control association studies on the possible association of candidate genes related to oxidative stress with risk for MS. Most studies have shown an increase in markers of oxidative stress, a decrease in antioxidant substances, or both, with cerebrospinal fluid and serum/plasma malonyl-dialdehyde being the most reliable markers. This topic requires further prospective, multicenter studies with a long-term follow-up period involving a large number of patients with MS and controls.

Oxidative stress-related risk of the multiple sclerosis development

Background

Multiple sclerosis (MS) is characterized by inflammation, demyelination and axonal degeneration. Oxidative stress (OS) plays a significant role in the pathogenesis of the disease. The aim of the study was to examine the association between OS and smoking on the MS development.

Methods

The study included 175 patients with relapsing-remitting multiple sclerosis (RRMS) (76 males, 99 females) and 254 healthy subjects (81 males and 173 females). Oxidative stress biomarkers in serum, Total Antioxidant Status (TAS) and Total Oxidative Status (TOS) were determined spectrophotometrically. Oxidative Stress Index (OSI) was calculated as the ratio of TOS and TAS. Urinary 8-oxo7,8-dihydro-2'-deoxyguanosine were determined by HPLC-MS/MS and expressed as 8-oxodG/creatinine.

Results

In females with RRMS were higher TOS, OSI and 8-oxodG/creatinine than in females in control group. The group of males with RRMS had lower level of TAS than the males in control group. Higher levels of 8-oxodG/creatinine was obtained in active, passive and former smokers with RRMS than in control group with the same exposition to tobacco smoke. Independent predictors of MS are passive smoking, increased OSI and increased levels of urinary 8-oxodG/creatinine.

Conclusions

Our results demonstrate that the OS parameters should be included in the assessment of the risk for MS development. Due to the more sensitivity to oxidative stress, females may be at higher risk of MS development. This data indicates the importance of introducing the antioxidant therapy as a complementary treatment in patients with RRMS.

Oxidative brain and cerebellum injury induced by d-galactosamine: Protective effect of S-methyl methionine sulfonium chloride

The objective of this study was to examine the protective effects of S-methyl methionine sulfonium chloride (MMSC) against galactosamine (GalN)-induced brain and cerebellum injury in rats. A total of 22 female Sprague-Dawley rats were randomly divided into four groups as follows: Group I (n = 5), intact animals; Group II (n = 6), animals received 50 mg/kg/day of MMSC by gavage technique for 3 consecutive days; Group III (n = 5), animals injected with a single dose of 500 mg/kg of GalN intraperitoneally (ip); and Group IV (n = 6), animals injected with the same dose of GalN 1 h after MMSC treatment. After 6 h of the last GalN treatment (at the end of the experiments), all animals were killed under anesthesia, brain and cerebellum tissues were dissected out. Reduced glutathione, total antioxidant status levels, and antioxidant enzymes (catalase, superoxide dismutase, and glutathione-related enzymes), aryl esterase, and carbonic anhydrase activities remarkably declined whereas advanced oxidized protein products, reactive oxygen species, total oxidant status, oxidative stress index levels, and myeloperoxidase, acetylcholinesterase, lactate dehydrogenase, and xanthine oxidase activities were significantly elevated in the GalN group compared with intact rats. In contrast, the administration of MMSC to GalN groups reversed these alterations. In conclusion, we may suggest that MMSC has protective effects against GalN-induced brain and cerebellar toxicity in rats.

Paraoxonase Role in Human Neurodegenerative Diseases

The human body has biological redox systems capable of preventing or mitigating the damage caused by increased oxidative stress throughout life. One of them are the paraoxonase (PON) enzymes. The PONs genetic cluster is made up of three members (PON1, PON2, PON3) that share a structural homology, located adjacent to chromosome seven. The most studied enzyme is PON1, which is associated with high density lipoprotein (HDL), having paraoxonase, arylesterase and lactonase activities. Due to these characteristics, the enzyme PON1 has been associated with the development of neurodegenerative diseases. Here we update the knowledge about the association of PON enzymes and their polymorphisms and the development of multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD) and Parkinson's disease (PD).

Oxidative Stress Marker Aberrations in Multiple Sclerosis: A Meta-Analysis Study

Oxidative stress has been suggested to play a key role in multiple sclerosis (MS), but clinical data on oxidative stress markers in MS patients were inconsistent. This study sought to quantitatively summarize the data of oxidative stress markers in the blood and cerebrospinal fluid (CSF) of patients with MS in the literature. We conducted a systematic search of PubMed and Web of Science and included studies if they provided data on the concentrations of oxidative stress markers in the peripheral blood and CSF of MS patients and healthy control (HC) subjects. The systematic search resulted in the inclusion of 31 studies with 2,001 MS patients and 2,212 HC subjects for meta-analysis. Random-effects meta-analysis demonstrated that patients with MS had significantly increased concentrations of blood oxidative stress markers compared with HC subjects for malondialdehyde (MDA; Hedges' g, 2.252; 95% CI, 1.080 to 3.424; p < 0.001) and lipid hydroperoxide by tert-butyl hydroperoxide-initiated chemiluminescence (CL-LOOH; Hedges' g, 0.383; 95% CI, 0.065 to 0.702; p = 0.018). In contrast, concentrations of albumin (Hedges' g, −1.036; CI, −1.679 to −0.394; p = 0.002) were significantly decreased in MS patients when compared with those in HC subjects. However, the other analyzed blood oxidative stress markers did not show significant differences between cases and controls. Furthermore, this meta-analysis showed significant association between CSF MDA and MS (Hedges' g, 3.275; 95% CI, 0.859 to 5.691; p = 0.008). Taken together, our results revealed increased blood and CSF MDA and decreased blood albumin levels in patients with MS, strengthening the clinical evidence of increased oxidative stress in MS.

Cladribine Treatment Improved Homocysteine Metabolism and Increased Total Serum Antioxidant Activity in Secondary Progressive Multiple Sclerosis Patients

Hyperhomocysteinemia plays a crucial role in the pathogenesis of many diseases of the central nervous system (CNS). The nervous system is particularly sensitive to high homocysteine (Hcy) level mainly due to its prooxidative and cytotoxic effects. Cladribine, a drug recently registered for the treatment of multiple sclerosis (MS), possesses additionally neuroprotective effects which are independent of its peripheral immunosuppressant action. Accumulating evidence suggests that oxidative stress and homocysteine thiolactone-mediated protein homocysteinylation play a causal role in MS. Both of these processes may be attenuated by paraoxonase 1 (PON1). Therefore, in the present study, we aimed to examine whether the beneficial effects of the drug in MS patients with a secondary progressive (SP) clinical course, treated with cladribine subcutaneously (s.c.), may be related to its ability to modify serum PON1 activity, Hcy concentration, and protein homocysteinylation, as well as to correct total antioxidant status. A total of 118 subjects were enrolled into the study: (1) patients with a SP type of MS, SP-MS (n = 40); (2) patients with a relapsing-remitting (RR) type of MS, RR-MS (n = 30); and (3) healthy people (n = 48). Patients with SP-MS were treated with cladribine. The drug was given in SP-SM patients s.c. six times every 6 weeks up to a total mean cumulative dose of 1.8 mg/kg. PON1 activity was assessed spectrophotometrically. The level of Hcy, homocysteine thiolactone (HTL) attached to plasma proteins (N-Hcy-protein), and antibodies against homocysteinylated proteins was assessed with an enzyme immunoassay. The total antioxidant activity of the serum was assessed with the ferric-reducing activity of plasma (FRAP) method. Basically, there was no difference in PON1 activity between untreated SP-MS, RR-MS, and control subjects. Serum Hcy was significantly higher in RR-MS patients (p < 0.001) and in SP-MS patients (p < 0.01) compared to the control group. The N-Hcy protein level was higher in RR-MS patients (p < 0.05) in comparison to the control group. Moreover, the elevated level of antibodies against homocysteinylated proteins was observed in the serum of patients with SP-MS. The total antioxidant capacity of serum was lower in MS patients vs. the control group (p < 0.001). After cladribine treatment, the activity of PON1 did not change in SP-MS patients, whereas cladribine treatment decreased the level of total Hcy (p < 0.05). Treatment with cladribine increased the total serum antioxidant activity in SP-MS patients (p < 0.01). The Expanded Disability Status Scale (EDSS) score did not change in SP-MS patients. Cladribine treatment in the SP-MS group attenuates hyperhomocysteinemia-induced protein homocysteinylation (n.s.). It also stabilises the neurological condition of SP-MS patients. The stabilisation of a neurological condition observed in SP-MS patients after cladribine treatment may be partially related to its ability to reduce elevated Hcy level and to improve serum antioxidant potential.

The Relation between Eating Habits and Abdominal Fat, Anthropometry, PON1 and IL-6 Levels in Patients with Multiple Sclerosis

BACKGROUND

Multiple sclerosis (MS) is a chronic neurodegenerative disease of an inflammatory, demyelinating and autoimmune nature. Diets with a high caloric density could be especially relevant in terms of the pathogenesis related to an increase in adipose tissue that is metabolically active and releases mediators, which can induce systemic inflammation and an increased oxidation state. The aim of this study was to analyse the eating habits related to calorie intake and their impact on abdominal obesity associated with anthropometric variables, the activity of the oxidation marker paraoxonase 1 (PON1), and interleukin 6 (IL-6) levelsin MS patients.

METHODS

An analytical and quantitative observational study was conducted with a population of 57 MS patients. The dietary-nutritional anamnesis was gained through the Food Frequency Questionnaire and a food diary. Diet and eating habits have been analysed through the Easy Diet-Programa de gestión de la consulta® software. Anthropometric measurements were taken in order to determine the presence of abdominal obesity. In addition, PON1 was quantified in serum by means of automated spectrophotometric assays and IL-6 was quantified using the ELISA technique.

RESULTS

A normal calorie intake was determined for women, yet a slightly lower intake was observed in men. Carbohydrate consumption was below what was established, and protein and lipids were over, in both cases. Furthermore, most patients had abdominal obesity, with significantly higher body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), fat percentage and IL-6 levels. IL-6 is greatly correlated with waist circumference and WHtR.

CONCLUSION

MS patients' nutrient intake shows an imbalance between macronutrients. This seems to favour the abdominal obesity associated with high values of proinflammatory IL-6 that is not correlated with a lower activity of PON1.

Paraoxonases Activities and Polymorphisms in Elderly and Old-Age Diseases: An Overview

Aging is defined as the accumulation of progressive organ dysfunction. There is much evidence linking the involvement of oxidative stress in the pathogenesis of aging. With increasing age, susceptibility to the development of diseases related to lipid peroxidation and tissue injury increases, due to chronic inflammatory processes, and production of reactive oxygen species (ROS) and free radicals. The paraoxonase (PON) gene family is composed of three members (PON1, PON2, PON3) that share considerable structural homology and are located adjacently on chromosome 7 in humans. The most studied member product is PON1, a protein associated with high-density lipoprotein with paraoxonase/esterase activity. Nevertheless, all the three proteins prevent oxidative stress. The major aim of this review is to highlight the importance of the role of PON enzymes in the aging process, and in the development of the main diseases present in the elderly: cardiovascular disease, diabetes mellitus, neurodegenerative diseases, and cancer.

Serum Paraoxonase, Arylesterase, and Glutathione-S-Transferase Activities and Oxidative Stress Levels in Patients with Mushroom Poisoning

OBJECTIVES

Consumption of toxic species of mushrooms may have detrimental effects and increase oxidative stress. Paraoxonase, arylesterase and glutathione-S-transferase are antioxidants that resist oxidative stress. In this study, we analyzed the changes in these enzymes during intoxication due to mushrooms.

METHODS

The study enrolled 49 adult patients with a diagnosis of mushroom poisoning according to clinical findings and 49 healthy volunteers as the control group. The patients with mild clinical findings were hospitalized due to the possibility that the patient had also eaten the mushrooms and due to clinical findings in the late period, which could be fatal. Paraoxonase, arylesterase, and glutathione-S-transferase concentrations, as well as total antioxidant and oxidant status, were determined in the 49 patients and 49 healthy volunteers by taking blood samples in the emergency department.

RESULTS

While paraoxonase, arylesterase, and total antioxidant status were significantly decreased in the patient group (p<0.05), glutathione-S-transferase, total oxidant status and the oxidative stress index were significantly higher (p<0.05). There was a positive correlation between the hospitalization time and the oxidative stress index (r=0.752, p<0.001), whereas a negative correlation was found with glutathione-S-transferase (r=-0.420, p=0.003).

CONCLUSION

We observed a significant decrease in paraoxonase and arylesterase and an increase in glutathione-S-transferase and oxidative stress indexes in patients with mushroom poisoning, indicating that these patients had an oxidative status. In particular, a low total antioxidant status and high oxidative stress index may gain importance in terms of the assessment of hospitalization duration.

The Evaluation of Oxidative Stress Parameters in Serum Patients with Relapsing-Remitting Multiple Sclerosis Treated with II-Line Immunomodulatory Therapy

Objectives

The assessment of oxidative stress (OS) in serum relapsing-remitting multiple sclerosis patients treated with II-line immunomodulatory therapy (fingolimod, natalizumab) compared to newly diagnosed patients (de novo group) treated with interferon (IFN) beta and controls. The relationship between OS parameters and gender, age, disease duration, Expanded Disability Status Scale, annualized relapse rate, MRI lesions in patients treated with II-line.

Materials and Methods

One hundred and twenty-one patients with RRMS were enrolled in the study. Patients were divided into groups: de novo group, IFN, fingolimod (FG), natalizumab (NT), and controls. Lipid hydroperoxides (LHP), malondialdehyde (MDA), lipofuscin (LPS), and total oxidative status (TOS) were determined.

Results

LHP, MDA, and TOS were lower in NT and FG groups compared to the de novo group. Levels of OS were different between NT and FG patients and the IFN group. Women treated with FG and NT had lower MDA, LPH, and TOS than women who were not treated while in men only LPH was lowered. Positive correlations were found between MDA, LHP, TOS, and ARR in the NT group.

Conclusion

The II-line immunomodulatory treatment decreased OS particularly among women. No difference in OS levels was observed between II-line therapy and IFN beta.

New Insights into the Role of Oxidative Stress Mechanisms in the Pathophysiology and Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a multifactorial disease of the central nervous system (CNS) characterized by an inflammatory process and demyelination. The etiology of the disease is still not fully understood. Therefore, finding new etiological factors is of such crucial importance. It is suspected that the development of MS may be affected by oxidative stress (OS). In the acute phase OS initiates inflammatory processes and in the chronic phase it sustains neurodegeneration. Redox processes in MS are associated with mitochondrial dysfunction, dysregulation of axonal bioenergetics, iron accumulation in the brain, impaired oxidant/antioxidant balance, and OS memory. The present paper is a review of the current literature about the role of OS in MS and it focuses on all major aspects. The article explains the mechanisms of OS, reports unique biomarkers with regard to their clinical significance, and presents a poorly understood relationship between OS and neurodegeneration. It also provides novel methods of treatment, including the use of antioxidants and the role of antioxidants in neuroprotection. Furthermore, adding new drugs in the treatment of relapse may be useful. The article considers the significance of OS in the current treatment of MS patients.

Decreased arylesterase activity of paraoxonase-1 (PON-1) might be a common denominator of neuroinflammatory and neurodegenerative diseases

High-density lipoprotein (HDL)-bound paraoxonase-1 (PON-1) is mechanistically related to oxidative stress, inflammation and atherosclerosis and this multirole nature positions the enzyme as potential pathogenic player and candidate biomarker for many diseases. Our previous work suggests that decline in serum PON-1 activities, i.e. arylesterase and paraoxonase, might be associated with the occurrence of mild cognitive impairment (MCI) to late onset Alzheimer's disease (LOAD) or vascular dementia (VAD). The present study aimed to: (1) expand our previous findings in a larger and different population, including patients with LOAD-VAD mixed dementia (MD); (2) explore a possible association between PON-1 and multiple sclerosis (MS); (3) evaluate if cerebrospinal fluid (CSF) levels of PON-1 activities might be useful biomarkers for MS. We found that serum arylesterase, but not paraoxonase, levels of PON-1 were significantly lower in patients affected by MCI (n=232), VAD (n=65), LOAD (n=175), MD (n=88) as well as those with MS (n=104) as compared to healthy controls. Notably, the most pronounced decline in this activity was shown by MD (-18%, p<0.01) and MS (-23%, p<0.001), while the lowest changes were detected in the MCI group (11%, p<0.05). Only arylesterase was detectable in the CSF of MS patients and the levels were not significantly different from those detected in the other two neurological control groups. Overall our data suggest that a depressed arylesterase activity could be a common denominator of different neurological diseases which, independently of their peculiar ethiopathogenesis and pathophysiology, appear to be all characterized by an altered systemic redox balance.

The pleiotropic role of HDL in autoimmune diseases

As is widely known, the classic function of HDL is reverse cholesterol transport (RCT), thus removing cholesterol from peripheral tissues. Early epidemiological studies, such as Framingham's, stated that increased HDL levels were associated with a significant decrease in relative risk for cardiovascular disease (CVD) mortality. However, those with heightened expectations in recent years for the development of therapeutic targets to increase HDL levels have been disappointed, because efforts have demonstrated the opposite effect on cardiovascular and global mortality. However, in contrast, studies have highlighted the complexity and the intriguing role of HDL in different pathological conditions, such as infections, neoplasms, and autoimmune diseases. In this review an attempt is made to summarize some biological pathways that link HDL function with the immune system, and its possible clinical repercussions in autoimmune diseases.

Ischemia modified albumin is an indicator of oxidative stress in multiple sclerosis

Introduction:

Oligodendrocytes need iron in processes of energy generation and myelination. However, excessive levels of iron may exert iron induced oxidative stress and thus lead to tissue degeneration. Monitoring oxidative stress will be of paramount importance in follow-up of patients with many diseases including multiple sclerosis (MS). The aim of this study was to measure total anti-oxidative status (TAS), total oxidative status (TOS) and ischemia modified albumin (IMA) in stable relapse remitting MS (RRMS) patients.

Materials and methods:

Thirty-five RRMS patients (15 males and 20 females; median age 42 (20–55) years) and thirty-five age-sex matched healthy controls (13 males and 22 females; median age 37 (21–60) years) were included in this study. All patients were diagnosed with MS according to the criteria of McDonald.

Results:

IMA levels were significantly higher in RRMS patients (P < 0.001), while TAS and TOS did not show any significant difference between groups (P = 0.870 and P = 0.460, respectively).

Conclusions:

Our results suggest IMA as a more efficient serum marker than TAS and TOS in detecting the oxidative stress in MS patients. Serum oxidative stress markers should be included in future study protocols besides clinical and radiological parameters.

Markers of oxidative stress in plasma and saliva in patients with multiple sclerosis

BACKROUND

Oxidative stress plays a role in multiple sclerosis. Saliva can be potentially used to study the disease progression or treatment, because of its non-invasiveness and easy collection. But studies on saliva and multiple sclerosis are missing. The aim of this study was to compare the concentrations of salivary oxidative stress markers in patients and healthy controls.

OBJECTIVE

Whole saliva and blood samples were collected from 29 patients and 29 healthy controls. Samples were collected during relapse, after corticosteroid therapy, and after three months. Markers of oxidative, carbonyl stress and antioxidant status were measured.

RESULTS

In plasma, thiobarbituric acid reacting substances, advanced oxidation protein products and fructosamine were significantly higher in patients compared to controls (by 271%, 46% and 24%, respectively; p<0.01). Total antioxidant capacity in plasma was lower by 20% (p<0.01) in patients versus controls. In saliva, higher levels of thiobarbituric acid reacting substances and advanced glycation end-products were observed in patients when compared to controls (by 51% and 49% respectively; p<0.01). Ferric reducing ability was reduced by 38% (p<0.05) in patients with multiple sclerosis.

CONCLUSION

According to our knowledge, this is the first report showing higher markers of oxidative stress and lower antioxidant status in patients with multiple sclerosis in saliva.