الفهرس 
ACKNOWLEDGEMENT
Clinical pictureOnly 14 pages are availabe for public view
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Abstract
Vitiligo is a chronic pigmentary disorder of the skin and mucous membranes that is characterized by persistent well-circumscribed, depigmented macules and patches caused by selective destruction of melanocytes. The worldwide prevalence of vitiligo ranges from a low of 0.06% to a high of 2.28%.
Several groups have reviewed the subject of vitiligo etiopathogenesis, but, despite the tremendous progress in molecular biology and genetics, there is still no universally accepted hypothesis.
Diverse pathogenic mechanisms have been proposed such as pigment cell structural aberration, oxidative stress, cathecholamines, alterations of cellular and humoral immunity, epidermal cytokines, metabolic dysregulations, melanocytorrhagia and a convergence hypothesis with simultaneous defects.
It has been speculated that there is an alteration of redox balance state of the vitiliginous skin. This results in dramatic production of ROS, as H2O2. ROS oxidize components of the cell leading to melanocytes’ destruction creating the depigmented macules.
This study is a case-control hospital-based study, aimed to signify the role of oxidative stress and apoptosis in the pathogenesis of vitiligo. It includes 50 vitiligo cases and 30 age and sex matched healthy volunteers as a control group. Patients and controls were selected according to proposed criteria. Blood samples and tissue specimens were taken to measure oxidative stress and apoptosis markers. Oxidative stress markers included; TAC, FoxO3a, zinc and iron as anti-oxidation markers and AOPP and MDA as oxidation markers. Apoptosis markers included Bcl-2, active caspase-9 (in serum) and inactive caspase (in tissue). Oxidative stress markers were measured biochemically using Elisa kits in serum and tissue. Apoptosis markers were measured biochemically using Elisa kits in serum and immunohistochemically in tissue by immunohistochemical staining using the avidin biotin immunoperoxidase complex technique.
The patients’ mean age was 32.6±12.4 years. 66% were females and 34% were males. The age of onset of vitiligo ranged from 6-53 years with a mean of 24.5±12.31 years. The duration of vitiligo ranged from 1-35 years with a mean of 8.21±6.49 years. Family history was present in 36% of patients and 50% of them had first-degree relative affection (18 % of total patients). 68% of patients had unstable vitiligo and 32% had stable type. History of koebner phenomenon was present in 40%. 56% of patients had skin type IV and 32% had skin type III. According to clinical type, 58% of patients presented with generalized type, 38% presented with acrofacial type and 4% with focal type. Leukotrichia was detected in 38% of patients. The VASI ranged from 0.25-29.6with a mean of 5.84±6.57.
Oxidative stress markers
Antioxidation markers
Regarding TAC
o TAC levels were significantly lower in serum and tissue of vitiligo patients than in controls.
o In patients, TAC level in lesional skin was significantly lower than in perilesional and unaffected skin and serum. However, the TAC level in serum was significantly lower than in unaffected skin. TAC level in lesional skin was significantly higher in patients with focal type than other types. In unaffected skin, it was significantly higher in focal type than in acrofacial type. TAC was significantly lower in all samples of patients with unstable disease. There was a significant positive correlation between TAC level in unaffected skin and VASI. However, no significant correlations were found between TAC levels in serum and tissues with age and disease duration.
Regarding FoxO3a
o No significant differences were found between serum FoxO3a levels in patients and controls, whereas lesional FoxO3a was significantly lower than its level in controls’ skin.
o In patients, FoxO3a level in lesional skin was significantly lower than in perilesional skin and unaffected skin. On the other hand, its level in serum was insignificantly lower than in lesional skin. However, its serum level was lower than its level in perilesional and unaffected skin. FoxO3a level in unaffected skin of patients with unstable disease was significantly lower than its level in stable disease. A significantly positive correlation between VASI and FoxO3a levels was found in perilesional and unaffected skin. However, no significant correlations were detected between FoxO3a levels in serum and tissues with age, disease duration and clinical type.
Regarding zinc
o Zinc levels were significantly lower in serum and tissue of vitiligo patients than in controls.
o In patients, zinc level in lesional skin was insignificantly lower than in perilesional skin and significantly lower than in unaffected skin and serum. However, its level in perilesional skin was significantly lower than unaffected skin. Regarding serum level, it was significantly higher than in perilesional skin and insignificantly higher than unaffected skin. Zinc level in serum increases significantly as the disease duration increases. In perilesional skin, zinc level was significantly higher in focal type than in acrofacial and generalized types. Whereas in unaffected skin, it was significantly higher in acrofacial type than in generalized type. No significant correlations were detected between zinc levels in serum and tissues with age, stability and VASI.
Regarding iron
o Iron levels were significantly lower in serum and tissue of vitiligo patients than in controls.
o In patients, the iron level in lesional skin was significantly lower than in perilesional skin, unaffected skin and serum. Its level was significantly lower in perilesional than in unaffected skin and significantly lower in serum than in unaffected skin. We noticed that serum iron level increases significantly as disease duration increases. Regarding stability, iron level in unaffected skin of patients with stable disease was significantly higher than its level in unstable patients. No significant correlations were detected between iron levels in serum and tissues with age, clinical type and VASI.
Oxidation markers
Regarding AOPP
o AOPP levels were significantly higher in serum and tissue of vitiligo patients than in controls.
o In patients, AOPP was significantly higher in lesional skin than in perilesional skin and unaffected skin, but it was insignificantly higher than in serum. Serum AOPP levels were significantly higher than perilesional and unaffected skin levels. Regarding stability, AOPP levels were significantly higher in serum, lesional and perilesional skin of patients with unstable vitiligo than in those with stable disease. No significant correlations were detected between AOPP levels in serum and tissues with age, disease duration, clinical type and VASI.
Regarding MDA
o MDA levels were significantly higher in serum and tissue of vitiligo patients than in controls.
o In patients, the MDA level was significantly higher in patients’ serum than in lesional, perilesional and unaffected skin. The lesional skin MDA level was significantly higher than its levels in perilesional and unaffected skin. Also, its level in perilesional skin was significantly higher than in unaffected skin. No significant correlations were detected between MDA levels in serum and tissues with age, disease duration, stability, clinical type and VASI.
Apoptosis markers
Regarding Bcl-2
o The Bcl-2 expression was insignificantly lower in serum of patients than controls. Whereas; its expression in lesional skin of patients was significantly lower than in skin of controls.
o In patients, the expression of Bcl-2 in lesional skin was significantly lower than in perilesional, unaffected skin and serum. The expression of Bcl-2 in perilesional skin was insignificantly lower than unaffected skin, and its level in unaffected skin was insignificantly lower than that in serum. However, the expression of Bcl-2 in perilesional skin was significantly lower than in serum. No significant correlations were detected between the levels of Bcl-2 in serum and tissues with age, disease duration, clinical types, stability and VASI.
Regarding active caspase-9 in serum and inactive caspase-9 in tissue
o Serum level of active caspase-9 in patients was significantly higher than in controls.
o Expression of inactive caspase-9 in lesional skin was significantly lower than in skin of controls.
o In patients, inactive caspase-9 expression was lower in lesional skin than in perilesional skin and lower in perilesional skin than in unaffected skin, however, the differences were insignificant.
o No significant correlations were detected between the levels of active caspase-9 in serum and inactive caspase-9 in tissue with age, disease duration, clinical type, stability and VASI.
Relation between antioxidation markers and apoptosis markers
In serum, no significant correlations were detected between the levels of TAC, zinc and iron with the Bcl-2 or active caspase-9 levels. There were significant positive correlations between the levels of FoxO3a with Bcl-2 and active caspase-9 levels.
In lesional skin, no significant correlations were found between the levels of TAC, FoxO3a, zinc and iron with Bcl-2 level. In addition, no significant correlations were detected between the levels of TAC, FoxO3a and iron with inactive caspase-9 levels. However, there was a significant positive correlation between the levels of zinc and inactive caspase-9.
In perilesional and unaffected skin, no significant correlations were detected between the levels of TAC, FoxO3a, zinc and iron with Bcl-2 or inactive caspase-9 levels.
Relation between oxidation markers and apoptosis markers
In serum, no significant correlations were detected between the levels of AOPP and MDA with Bcl-2 or active caspase-9.
In lesional and unaffected skin, no significant correlations were detected between the levels of AOPP and MDA with Bcl-2 or inactive caspase-9.
In perilesional skin, no significant correlations were detected between the levels of AOPP with Bcl-2 or inactive caspase-9. However, there was a significant positive correlation between the levels of MDA and Bcl-2. No significant correlation was detected between MDA and inactive caspase-9.