Expression of apoptosis regulatory markers in the skin of advanced hepatitis-C virus liver patients

Abstract

Background: Hepatitis-C virus (HCV) infection is considered a major worldwide public health problem with a global prevalence. Maintenance of skin homeostasis requires a delicate balance between proliferation, differentiation, and apoptosis. Meanwhile, it is unclear if there is an altered keratinocyte proliferation/apoptosis balance in advanced liver disease with HCV infection.

Aim: This work aimed to evaluate the epidermal thickness and changes in the expression of apoptosis regulatory markers as well as apoptotic index in skin samples of advanced HCV liver patients compared to normal controls.

Materials and methods: Twenty biopsies were taken from apparently normal skin of advanced HCV liver disease patients, as well as five healthy control subjects. These specimens were used for histometric epidermal measurement, immunohistochemical staining of apoptosis regulatory proteins (Bax, Fas, p53, Caspase-3, Bcl-2, Bcl-xL) as well as the TUNEL technique for detection of apoptotic cells.

Results: The mean epidermal thickness was significantly lower than the control group (P=0.000). There were significant overexpression of pro-apoptotic markers (Bax, Fas, P53, and Caspase-3) in patients (P=0.03, 0.03, 0.003, 0.003 respectively), with increased apoptotic index in HCV liver patients (P=0.002) when compared to normal controls. On the other hand, no statistically significant difference were encountered in the expression of antiapoptotic markers (Bcl-2, Bcl-xL) in HCV patients when compared to normal controls (P=0.5, 0.9, respectively).

Conclusion: These findings suggest that an alteration in the proliferation/apoptosis balance is present in the skin of HCV liver patients.

Keywords: Apoptosis; Bcl-2; epidermal thickness; hepatitis-C virus; liver disease.

Figure 1

The epidermis of advanced HCV liver disease patients (a) is lower in thickness when compared to controls (b) (H and E, ×100)

Figure 2

Expression of pro-apoptotic (Bax, Fas, P53, Caspase-3) and anti-apoptotic (Bcl-2, Bcl-xL) markers, and apoptotic index in HCV liver patients and controls

Figure 3

Expression of pro-apoptotic markers (Bax, Fas, p53, Caspase-3) in epidermal keratinocytes of advanced HCV liver disease patients (a,c,e,g) and in controls (b,d,f,h) respectively showing the following:

1. Significant increase of cytoplasmic expression of Bax staining in basal and squamous cell layers in patients (a) when compared to that confined to the basal cell layer of controls (b) (Immunohistochemical, ×400).

2. Significant increase of membranous expression of Fas staining in basal and lower 2/3 of squamous cell layers in patients (c) when compared to that confined to the basal cell layer of controls (d) (Immunohistochemical, ×400).

3. Significant increase of nuclear expression of P53 staining in basal and lower 2/3 of squamous cell layers in patients (e) when compared to that confined to the basal cell layer of controls (f) (Immunohistochemical, ×200).

4. Significant increase of cytoplasmic expression of Caspase 3 staining in basal and squamous cell layers in patients (g) when compared to minimal staining confined to the basal cell layer of controls (h) (Immunohistochemical, ×400)

Figure 4

Expression of anti-apoptotic markers (Bcl-2, Bcl-xL) in epidermal keratinocytes of advanced HCV liver disease patients (a,c) and in controls (b,d):

1. Insiginificant lower cytoplasmic expression of Bcl-2 staining, mainly confined to the basal cell layer, in patients (a) when compared to controls (b).

2. Insiginificant lower perinuclear cytoplasmic expression of Bcl-xL staining, mainly confined to the basal cell layer, in patients (c) when compared to that confined to the basal and supra basal cell layer of controls (d) (Immunohistochemical, ×400).

Figure 5

Many apoptotic cells present in basal and squamous cell layer in advanced HCV liver disease patients (a), compared to few apoptotic cells seen in controls (b) (TUNEL, ×400)