Acne vulgaris is the most common cutaneous disorder manifested by comedones, papules, pustules and cysts. The etiology of acne appears to be multifactorial, involving follicular hyperkeratinization, hormonal function, proliferation of Propionibacterium acnes, increased sebum production and inflammation. Despite a significant body of scientific literature, the sequence of events leading to the production of acne lesions is not well understood [1]. Specific dietary agents and certain supplements are known to enhance the health and appearance of the skin by improving immune function at the skin level and providing therapeutic bioactive agents that assist in the treatment of many skin conditions, such as psoriasis, eczema and acne [2,3]. It has become increasingly clear that nutritional factors such as vitamins and minerals are involved in the pathogenesis of acne [4]. Previous studies over the last three decades have shown that zinc (Zn) levels are lower in acne patients than healthy subjects and that oral and topical combination of zinc may be of therapeutic value [5,6]. Pohit et al. in 1985 suggest that people with acne have lower-than-normal levels of Zn in their bodies [7]. This fact alone does not prove that taking zinc supplements will help acne, but several small double-blind studies involving a total of more than 300 people have found generally positive results [8].The results of El-Saaiee et al. in 1983 revealed differences in the copper and iron content of the sera between 30 individuals complaining of moderate acne vulgaris type II and healthy individuals, although they were statistically not significant. The Zn content showed no changes compared to the control group [9].

Recently, Nasiri et al. in 2009 indicated that serum zinc levels in 30 Iranian acne patients were lower than that of 35 healthy controls; however, this difference was not significant (P=0.32) [10].

Many studies including an epidemiological Iraqi study had showed that acne vulgaris in general was more common in males than females (74.24%) versus (61.9%) [11-13]. On literature review, we found several studies, of which [14], conducted on female patients with acne to investigate the pathogenesis of this disease, however, few involved male acne patients. Therefore, the aim of the present study is to assess the serum concentrations of zinc, copper, and magnesium in male Iraqi patients with acne vulgaris and to clarify their correlation with the severity of acne.

This case controlled study was carried out in the Department of Biochemistry, College of Medicine, in the Dermatology and Venerology and in the Poisoning Consultation Center of Baghdad Teaching Hospital, Iraq, from May 2009 to January 2010. The study involved 45 male patients with acne vulgaris, aged range between 18- 30 (mean ± SD; 21.82 ± 3.77 years). Patients were divided into three groups according to the severity of their acne. A mild acne group that included 15 patients a moderate acne group of 15 patients and severe acne group of 15 patients. Scoring the severity of acne was according to the following rule:

Mild acne

In which the count of papules is less than 10 and the count of pustules is less than 20.

Moderate acne

In which the count of papules ranges from 10 to 30 and the count of pustules ranges from 20 to 40.

Severe acne

In which the count of papules is more than 30 and the count of pustules is more than 40 [15]. Exclusion criteria were intake of oral zinc, magnesium, or copper supplements or multivitamins containing such elements three months before the study, and the presence of any metabolic disease that affected serum elements levels. Control group consisted of 45 healthy males without acne, and were matched for age 18-30 years (mean ± SD; 22.18 ± 3.85 years), and body mass index (mean ± SD; 23.04 ± 1.38 Kg/m²).

Five milliliters of peripheral venous blood was collected from each patient and control male in plain test tubes, left to clot, then centrifuged at 2500 rpm for 10 minute. The separated serum stored at -20°C until the time of mineral assay.

Serum zinc, copper, and magnesium were determined using flame atomic absorption spectrophotometer (AA-646 Shimazdzu, Japan). Samples were diluted 1:10 with n- butanol solution as diluents [16]. Levels of serum Zn, Cu, and Mg were calculated after application of absorbancies on suitable calibration curve for each element made from standard solutions.

SPSS version 6 for window was used for all statistical analysis. Statistical significance was assessed by ANOVA and student t-tests. The linear regression test was applied for the correlation between different parameters, and the significance of the r-value was checked using t-test. P-values of less than 0.05 were considered significant.

Table 1 shows the clinical [age and BMI values as mean (±SD)] and biochemical data for healthy male subjects and male patients with acne. The results showed that the mean (± SD) value of serum Zn levels of acne patients (97.33 ± 17.50 mg/dl) was lower than that of controls (102.42 ± 18.10 mg/dl), but the difference did not reach the significant level. Similarly, the mean (± SD) values of serum Cu and Mg levels did not differ significantly between acne male patients and controls (Table 1).

Table 1: Clinical and biochemical data for healthy male controls and patients with acne vulgaris.

The mean (±SD) values of serum Zn, Cu, and Mg concentrations in patients with –mild, -moderate, and –severe acne types and male controls group are shown in Table 2 and Figures 1 and 2. These results revealed that mean value of serum Zn levels of severe acne (79.67 ± 7.19 mg/dl) was significantly lower than that of healthy males (102.42 ± 18.10 mg/dl, P=0.0001), mild acne- (116.67 ± 12.34 mg/dl, P=0.0001), and moderate acne- types (95.67 ± 4.58 mg/dl, P=0.003). Moreover, patients with moderate type of acne had significantly lower levels of serum Zn mean (± SD) value than that of mild acne type (P= 0.0001). The mean (±SD) value of serum Cu levels did not differ significantly between the acne group types and controls as well as between the acne patient groups themselves. With regard to serum Mg serum level, the mean (±SD) value of serum Mg levels was significantly decreased in severe type of acne patients (1.13 ± 0.20 mg/dl) when compared with that of mild acne type (1.29 ± 0.18 mg/dl, P=0.011). However, the mean values of serum Zn, Cu, and Mg concentrations of acne patients did not differ significantly with respect to their BMI values. Furthermore, the results of the present study revealed no significant correlation between the serum levels of the studied elements (Zn, Cu, and Mg) and the values of BMI and age of patient and control groups (p>0.05).

Table 2: Mean ( ± SD) values of Serum Zinc, Copper, and Magnesium Concentrations in Healthy Male Controls and Patients with Mild-, Moderate,- and Severe Acne Vulgaris.

Figure 1: Serum Concentrations of Zinc (μg/dl), Copper (μg/dl) in healthy control, Mild-, Moderate-, and Severe acne patients groups.

Figure 2: Serum concentration of Magnesium (mg/dl) in Healthy Control, Mild-, Moderate-, and Severe acne patients groups.

The present study showed that serum Zn level was lower in acne patients than in healthy male controls, but the difference was not significant. This finding is consistent with that observed by Nasiri et al. in 2009 [10] who found insignificant decrease of serum Zn in their Iranian people compared with healthy controls. However, the present study has shown that serum Zn levels of the severe type of acne were significantly lower than that of healthy controls, mild, and moderate types of acne. These data are in agreement with that reported by Michaelsson et al. and Amer et al. [17,18] who showed that serum Zn level was significantly reduced in severe acne male patients compared with controls. These authors suggested that low levels of zinc in the serum of patients with severe acne may provide a rational for the beneficial effect of oral zinc treatment seen in clinical practice [17]. The mineral zinc is emerging as vital nutrient for skin health and appearance. Zinc nutritional status is necessary for oil gland function, local skin hormone activation, wound healing, skin inflammation control and regeneration of skin cells. Zinc supplementation has been used with success in the treatment of many acne cases [19]. Studies indicated that most individuals consume only 8-9 mg/day of zinc from dietary sources, whereas the recommended daily acquirement (RDA) for zinc is set at 15 mg/day for adults [20]. A review reported by Dr. Preston, indicated that lack of zinc is a recipe for acne [21]. Nasiri et al. in 2009 concluded from their study that zinc as anti-inflammatory element may play a role in the pathogenesis of acne, and there is a need for further studies [10].

The present study also found that serum magnesium level was significantly decreased in severe type of acne compared with mild acne patients. This element (Mg) is vital for the production of proteins and enzymes in every tissue of the body. This includes the proteins and enzymes of skin cells where new cells are constantly being produced. It is also absolutely essential for the proper use of the vitamin Pyridoxine [21]. The author of the latter review suggested taking supplements of about 500 mg of this mineral each day is essential.

Copper is an important element for numerous metalloenzymes and metalloproteins such as superoxide dismutase that are involved in energy and antioxidant metabolism. Human keratinocytes are susceptible to peroxidative damage because they contain high concentrations of polyunsaturated fatty acids and also possess a significant ability to generate a reactive oxygen species (ROS), mainly superoxide anion and hydrogen peroxide. Superoxide dismutase (Cu-metalloenzyme) protects human skin cell from this peroxidative damage [22]. Although, this study showed that there was no significant difference in serum copper level between patient and control groups; Further studies are needed to show the beneficial effect of Cu compounds in prevention and treatment of acne vulgaris.

Elements are also important to mammalian target of rapamycin (mTOR) protein. This serine and threonine protein kinase regulates protein translation through a rapamycin-sensitive pathway. mTOR protein integrates signals from mitogens and the nutrients, glucose and amino acids, to regulate cellular growth and profileration. The study of Lynch et al. [23] indicated that Zn²⁺ regulates, but is not absolutely required for, mTOR protein kinase activity. Zinc also stimulated a recombinant human form of mTOR. The stimulatory effects of Zn²⁺ were maximal at ∼100 μM but decreased and became inhibitory at higher physiologically irrelevant concentrations. Micromolar concentrations of other divalent cations, Ca²⁺, Fe²⁺, and Mn²⁺, had no effect on the protein kinase activity of mTOR in the presence of excess Mg²⁺. These authors also suggested that zinc acts at multiple steps in amino acid- and insulin cell-signaling pathways, including mTOR, and that the additive effects of Zn²⁺ on these steps may thereby promote insulin and nutritional signaling. A study conducted by Saleh concluded that male Iraqi acne patients, particularly those suffering from the severe type, have a significant elevation of serum levels of growth hormone (GH) and insulin like growth factor-(IGF)-1, which can stimulate androgen hormone synthesis and secretion, leading to the proliferation of sebocytes and keratinocytes resulting in aggravation of acne [24] The results of the study conducted by Savastano et al. [25] underlined that spleen enlargement, a parameter expressing low-grade chronic inflammatory status, was a major determinant of low IGF-I/ IGFBP-3 ratio than hepatic steatosis per se. The investigators also found a significant negative correlation between all the components of the IGF-I axis investigated and fat mass % (FM %), insulin resistance, or hepatic steatosis severity. However, FM% was a better determinant of IGF-I and IGFBP-1 than HS per se in the same population. In Conclusion; the present study revealed significant association between each of Zn and Mg levels with the severity of acne. Further studies that deal with serum concentrations of zinc, magnesium and mTOR in severe acne patients are required.

We would like to thank Assist. Prof. Maysaa Jalal (Ph D student Clinical Biochem, Biochemistry Department, College of Medicine, Baghdad) for help with statistical calculations.