The Oxidant and Antioxidant Status in Pityriasis Rosea

Abstract

Background:

Pityriasis rosea (PR) is usually an asymptomatic and self-limiting papulosquamous skin disease with acute onset. The etiology has not been clarified yet. Recently, increased oxidative stress was found to play a role in etiopathogenesis of multiple cutaneous diseases with T cell-mediated immune response. However, there are no studies demonstrating the oxidative stress status in PR.

Aim:

The aim of the study is to determine the status of oxidative stress (OS) and paraoxonase (PON) 1/arylesterase enzyme activities in PR.

Materials and Methods:

Study included 51 patients with active PR lesions, and 45 healthy volunteers. Serum levels of total oxidant status (TOS), total antioxidant status (TAS), and PON1/arylesterase (ARES) activity were determined and oxidative stress index (OSI) was calculated in all patients and controls.

Results:

TAS levels and ARES activities in the patient group were significantly lower than the control group. On the other hand, TOS and OSI levels were significantly higher in patients compared with controls. There was no significant correlation between the duration of disease and TAS, TOS, OSI levels, and ARES activities.

Conclusion:

A systemic oxidative stress exists in PR, which suggests that OS may be involved in the etiopathogenesis of disease.

Introduction

What was known?

PR may be seen all over the world and peaks during adolescence. The etiology of PR has not been completely elucidated.

Pityriasis rosea (PR) is usually an asymptomatic and self-limiting cutaneous disease with papulosquamous eruptions and acute onset. It is more frequent in young, healthy individuals. The disease may be seen all over the world and peaks during adolescence. Patients with PR are estimated to constitute 2% of the attendants of outpatient dermatology polyclinics.[1] Although there are epidemiological studies reporting an increased prevalence in autumn and winter, majority of the studies do not report any seasonal differences.[2,3,4,5] A typical eruption continues for about 4-6 weeks; however, sometimes it may continue for 5 months or more. Pink colored papulosquamous lesions appear parallel to cutaneous lines, particularly in the body, and these follow the initial lesions called medallion plaques.[6]

The etiology of PR has not been completely elucidated. The rash does not look like exanthema and the disease rarely reoccurs or does not reoccur at all. It has been reported with increased frequency in some societies. Some possible infectious origins have been suggested, with human herpes virus (HHV) 6, HHV 7, Epstein-Barr virus (EBV), and cytomegalovirus (CMV) having been blamed for the etiology of PR; however, no exact correlation has ever been shown. Although HHV 6 and 7 appear to be the infectious agents most associated with PR, the findings regarding these viruses are contradictory.[7,8,9,10] Pityriasis rosea is known to occur most often with a weakened immune system and has also been suggested to take place with psychological stress-induced immune suppression rather than being psychosomatic in nature.[1]

A histopathological evaluation of PR revealed the predominance of a T cell-mediated immune system.[11,12] Moreover, studies on other T cell-mediated cutaneous diseases; such as psoriasis, contact dermatitis, and atopic dermatitis; have demonstrated an increase in oxidative stress (OS).[13,14,15] However, there are no studies showing the role of OS concerning inflammatory response of PR. In this study, we aimed to determine the oxidant and antioxidant status of PR patients by measuring total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI) levels, paraoxonase 1/arylesterase (PON1/ARES) activity and investigate the association between determined oxidative stress parameters and disease duration.

Materials and Methods

A single center, prospective, controlled study was conducted with 51 patients who were clinically and/or histopathologically diagnosed as having PR and 45 healthy controls between December 2011 and June 2012. The patients had active lesions. Neither patients nor controls were on any local and/or systemic treatments. Pregnant or nursing women, any subjects who had cardiac, renal or hepatic disease, diabetes mellitus, a positive HIV test, allergies or active infection, and smokers and alcohol users were excluded from the study. The study was conducted in accordance with the guidelines of Good Clinical Practice (GCP) and Declaration of Helsinki and the Clinical Research Ethics Committee of the hospital approved the study. All participants signed the written informed consent.

Blood sampling

Following 12 h of fasting in the morning, 8 cm³ of blood samples were drawn from the antecubital vein using a 21 G needle after cleaning the injection site with alcohol, and these were placed in biochemistry test tubes. The samples rested for 30 min and then were centrifuged at 2,500 g for 10 min to separate the serum. Hemolyzed blood samples were not included. The samples were then returned to the test tubes and stored in a deep freezer at -80°C (Sanyo, Japan) until the test date.

Measurement of serum TOS

The TOS of the serum was measured using an automated colorimetric measurement method for TOS.[16] In this method, the oxidants present in the sample oxidized the ferrous ion-o-dianisidine complex to ferric ion. The oxidation reaction was enhanced by glycerol molecules, which are abundantly present in the reaction medium. The ferric ion produced a colored complex with xylenol orange in an acidic medium. The color intensity, which could be measured spectrophotometrically, was related to the total amount of oxidant molecules present in the sample. The assay was calibrated with hydrogen peroxide and the results are expressed in terms of micromolar hydrogen peroxide equivalent per liter (μmol H₂O₂ Eq/L).

Measurement of serum TAS

The total antioxidant levels of the serum was measured using an automated colorimetric measurement method for TAS.[17] This method is based on the bleaching of characteristic color of a more stable ABTS (2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) radical cation by antioxidants. The assay has excellent precision values, which are lower than 3%. The results were expressed as mmol Trolox (Rel Assay) equivalent/L. Rel Assay™ commercial kit is convenient for all autoanalyzers which determine fastness of measurement. In this study the Rel Assay analyzer, provided by Mega Tip (Gaziantep, Turkey), was used and speed of the analyzer was 200 tests in 1 h. Rel Assay commercial kit works on the basis of a colorimetric method at 660 nm absorbance.

Determination of OSI

The ratio of TOS to TAS represents the OSI, an indicator of the degree of oxidative stress. The OSI value is calculated according to the formula[18] in which TAS values were converted to μmol/L:

OSI (arbitrary unit) = [TOS (μmol H₂O₂ Eq/L)/TAS (μmol Trolox Eq/L)] × 100.

Measurement of serum PON1/arylesterase activities

Serum PON1/arylesterase (ARES) activity was measured by using commercially available kits (Rel Assay Diagnostics, Mega Tύp, Gaziantep, Turkey). Serum ARES activity was determined by the presence of phenol following the reaction of phenylacetate. The molar extinction coefficient of phenol was 4,000 M^-1 cm^-1; the results were expressed as kU/L.

Statistical analysis

Evaluation of normality was performed with the Shapiro-Wilk test. Normally distributed continuous variables were expressed as mean and standard deviation (mean ± SD), and were compared with Student's t-test for independent groups. Non-normally distributed continuous variables were expressed as median and range (minimum-maximum) and were compared with Mann-Whitney U test for independent groups. Categorical variables are reported as number and percentage and compared with the Chi-square test. The association between continuous variables was explored by Pearson (normally distributed) or Spearman (non-normally scattered) correlation analysis. Statistical significance was considered at a two-tailed value of P < 0.05. Statistical analyses were performed using Statistical Package for the Social Sciences (SPSS), version 16.0; SPSS Inc., Chicago, IL.

Results

Of the 51 patients, 25 (49.0%) were males and 26 (51.0%) were females (median age: 28.0 years). The control group consisted of 45 subjects with 20 (44.4%) males and 25 (55.6%) females (median age: 28.0 years) [Table 1]. There were no significant differences between the patient and control groups with regards to age and gender (P = 0.888 and P = 0.654, respectively). The range of disease duration was 3-90 days (median: 10.5 days).

Table 1.

Baseline characteristics of the patients and controls

The total cholesterol, high density lipoprotein (HDL), triglyceride (TG), and low density lipoprotein (LDL) levels of both patient and control groups were within normal ranges, and these values did not differ between the two groups (all P < 0.05) [Table 2].

Table 2.

The HDL, TG, LDL, alanine aminotransferase, and aspartate aminotransferase levels of patients with pityriasis rosea and controls

The TAS levels and ARES activities of the patient group were statistically significantly lower than those of the control group (P = 0.000), whereas the TOS and OSI levels of the patient group were statistically significantly higher than the control group (P = 0.000) [Table 3]. No significant correlation was found between the disease duration and TAS, TOS, OSI levels, and ARES activities [Table 4].

Table 3.

Serum total antioxidant status, total oxidant status levels, oxidative stress index, and arylesterase activities of patients with PR and controls

Table 4.

Correlation between disease duration and oxidative stress parameters including TAS, TOS, OSI, and ARES activity

Discussion

Although PR was first described in 1860 by the French dermatologist Camille Melchior Gilbert and is now recognized as a worldwide disease, its etiology and pathogenesis have not been clearly identified.[1,10] The inflammatory response in PR occurs due to activation of cellular immunity. The demonstration of role of OS in other T cell-mediated diseases; for example, psoriasis, contact dermatitis, and atopic dermatitis; led us to consider role of OS in PR, another T cell-mediated disease. Therefore, the OS parameters including TAS, TOS, and OSI were investigated in our study. An imbalance due to an increase in generation of oxidative products or decrease in endogenous antioxidative protection mechanism is called OS.[19] In order to determine OS, TOS levels which reflects the total amount of oxidative products in the body, were assessed. By measuring TOS levels, many of OS products in the serum were determined, such as reactive nitrogen types (RNT), hydrochloric acid, malonylaldehyde (MDA), and lipid peroxides.[16]

In this study, the TAS was used to measure the sum of antioxidant molecules.[17] When the oxidative products increase dramatically, the production of antioxidant protection systems also increases accordingly to try and maintain functional integrity.[13] Therefore, separate identification of TAS and TOS levels may be insufficient to reflect the stress status. OSI is the most significant parameter used to reflect OS status. OS is obtained by estimating the TOS/TAS ratio.[20] This study, which demonstrated the oxidant and antioxidant status, revealed that the TOS levels of PR patients significantly increased compared with the healthy control group, whereas the TAS levels were significantly decreased. In addition to these findings, increase in OS was ideally supported by markedly higher OSI levels in patients than healthy controls. This increase occurred due to the presence of both excess oxidant generation and decreased levels of antioxidant products.

Oxidative stress affects the skin by stimulating production and release of proinflammatory cytokines which play an important role in the development of cutaneous disorders.[21] Today, OS is known to be the culprit in development of pathogenesis of more than a hundred diseases, including allergic and inflammatory cutaneous disorders, vitiligo, psoriasis, acne vulgaris, atopic dermatitis, Behcet's disease, and cutaneous cancers.[20,22] Increased oxidant molecules in OS, such as ROT and RNT, results in oxidative damage that leads to an increased release of inflammatory cytokines.[23] Under these circumstances, orally administered antioxidant nutritional support is shown to decrease cytokines that resemble tumor necrosis factor-alpha (TNF-α) and interleukin-1 (IL-1).[24] Topically administered antioxidants were also shown to protect the skin against oxidative damage and speed up healing of damaged skin.[25,26,27]

In our study, patients with PR had increased OS, which suggested that OS may play a role in etiopathogenesis of PR. Polyunsaturated fatty acids (PUFA), which exist in the composition of membrane phospholipids, have a critical role in the maintenance of normal structures and functions of epidermal cells, and they are the most sensitive compounds with regard to lipid peroxidation by free radicals. Oxidation of the PUFA in cell membrane is most important indicator of OS. Therefore, oxidation changes the lipid structure of membrane and breaks down the composition and functions of the cell. Previous studies have shown that abnormalities in essential fatty acid metabolism may play a role in inflammatory dermatoses, for instance atopic eczema, acne, and psoriasis. Plasma deficiency of PUFA in animals induces manifestations on the skin characterized by scaly dermatoses, hyperproliferation of the epidermis, hyperkeratosis, hypergranulosis, achanthosis, and erythema.[28] The major component of the antioxidant properties of HDL originates from PON1. The ARES activity represents one of the antioxidant enzymatic activities of PON1 enzyme, which has an important role in modulating OS and in protection from cardiovascular diseases.[29] In our study, serum ARES levels were found to be significantly lower in the patient group than in the control group.

A cross-sectional investigation was performed in this study to determine the OS status of patients. Our investigations did not reveal a correlation between OS and disease duration. However, this finding does not explain whether OS is effective in the duration of PR. Sequential measurements and comparisons within various periods in larger patient groups are needed to investigate the association between disease duration and OS. Another limitation in our study was that, OS status of the patient was not investigated after the lesions disappeared. Despite these limitations, this study is important for being the first investigation demonstrating increase of OS in PR and for providing new ideas to clarify the pathogenesis.

Although the PR lesions improved after approximately 4 weeks in most of the patients as expected in this study, it is not known why the disease lasted for months for some. All of the patients included had active PR lesions and duration of lesions varied between 3 and 90 days at the time the patients were enrolled. We did not determine any positive or negative correlation between disease duration and OS parameters among patients with acute disease or those with a long duration. The most important finding revealed by our study was increased levels of OS in patients with acute disease and in those with longer disease duration, such as 3 months, compared with the healthy subjects. This suggests that the lesions may continue longer in chronic OS status. Discovering the triggering mechanisms leading to chronic OS, needs to provide detailed information of the disease pathogenesis. Although PR is a common skin disorder, there are a few studies about its pathogenesis. The previous studies were frequently focused on viral etiology, in which findings could not demonstrate a certain relationship with PR. In the present study, we performed a different evaluation and investigated if OS was affected in patients with PR. It is not clear if increased OS is related to inflammation of disease or if PR is triggered in patients with higher OS. New studies are needed to clarify this important issue. Since there is limited number of studies about PR, the results of our study were compared with other inflammatory disorders. In conclusion, this study demonstrates a different evaluation of PR and gives rise to future studies on the etiopathogenesis of the disorder.

What is new?

TAS levels and ARES activities in patients with PR were significantly lower than the healthy controls. On the other hand, TOS and OSI levels were significantly higher in patients compared with controls. Patients with PR had increased systemic OS, which suggested that OS may play a role in etiopathogenesis of PR.