BACKGROUND: Hair loss following skin inflammation may in part be mediated by keratinocyte (KC) apoptosis. While the effects of different cytokines or other apoptosis stimulating agents such as interferon (IFN)-gamma or tumour necrosis factor (TNF)-alpha on KC apoptosis in vitro have been addressed in several studies, little is known about the effects of proinflammatory cytokines on KC apoptosis in vivo. OBJECTIVES: To study the effects of intradermally injected TNF-alpha, interleukin (IL)-1beta and IFN-gamma on KC apoptosis in the back skin of C57BL/6 mice. METHODS: Apoptosis in epidermal and hair bulb KCs was analysed by immunohistology using TUNEL staining. RESULTS: Injection of TNF-alpha induced a significantly higher number of apoptotic cells within the epidermis than vehicle; all three proinflammatory cytokines together further increased their number. Intrafollicular hair bulb KCs were much more susceptible to apoptosis induction by TNF-alpha or IL-1beta; their injection significantly upregulated apoptosis after 6 h, which was further increased after 24 h. The combination of all cytokines together accelerated intrafollicular apoptosis after 6 h by doubling the number of apoptotic cells per hair bulb, compared with the effects of TNF-alpha or IL-1beta alone. CONCLUSIONS: These data suggest that programmed cell death of proliferating KCs in vivo can be induced by proinflammatory cytokines.
BACKGROUND:Hair loss following skin inflammation may in part be mediated by keratinocyte (KC) apoptosis. While the effects of different cytokines or other apoptosis stimulating agents such as interferon (IFN)-gamma or tumour necrosis factor (TNF)-alpha on KC apoptosis in vitro have been addressed in several studies, little is known about the effects of proinflammatory cytokines on KC apoptosis in vivo. OBJECTIVES: To study the effects of intradermally injected TNF-alpha, interleukin (IL)-1beta and IFN-gamma on KC apoptosis in the back skin of C57BL/6 mice. METHODS: Apoptosis in epidermal and hair bulb KCs was analysed by immunohistology using TUNEL staining. RESULTS: Injection of TNF-alpha induced a significantly higher number of apoptotic cells within the epidermis than vehicle; all three proinflammatory cytokines together further increased their number. Intrafollicular hair bulb KCs were much more susceptible to apoptosis induction by TNF-alpha or IL-1beta; their injection significantly upregulated apoptosis after 6 h, which was further increased after 24 h. The combination of all cytokines together accelerated intrafollicular apoptosis after 6 h by doubling the number of apoptotic cells per hair bulb, compared with the effects of TNF-alpha or IL-1beta alone. CONCLUSIONS: These data suggest that programmed cell death of proliferating KCs in vivo can be induced by proinflammatory cytokines.
Authors: Kyros Ipaktchi; Aladdein Mattar; Andreas D Niederbichler; Laszlo M Hoesel; Sabrina Vollmannshauser; Mark R Hemmila; Rebecca M Minter; Grace L Su; Stewart C Wang; Saman Arbabi Journal: Surgery Date: 2007-07 Impact factor: 3.982
Authors: Petra Clara Arck; Bori Handjiski; Eva Milena J Peters; Anita S Peter; Evelin Hagen; Axel Fischer; Burghard F Klapp; Ralf Paus Journal: Am J Pathol Date: 2003-03 Impact factor: 4.307
Authors: Petra C Arck; Bori Handjiski; Arne Kuhlmei; Eva M J Peters; Maike Knackstedt; Anita Peter; Stephen P Hunt; Burghard F Klapp; Ralf Paus Journal: J Mol Med (Berl) Date: 2005-03-10 Impact factor: 4.599
Authors: Eva Milena J Peters; Bori Handjiski; Arne Kuhlmei; Evelin Hagen; Hannes Bielas; Armin Braun; Burghard F Klapp; Ralf Paus; Petra Clara Arck Journal: Am J Pathol Date: 2004-07 Impact factor: 4.307
Authors: Eva M J Peters; Sofia Liotiri; Eniko Bodó; Evelin Hagen; Tamás Bíró; Petra C Arck; Ralf Paus Journal: Am J Pathol Date: 2007-11-30 Impact factor: 4.307