Mellová Y

Alterations in the rat forebrain apoptosis following exposure to ionizing radiation

Ionizing radiation commonly used in the radiotherapy of brain tumours can cause adverse side effects to surrounding normal brain tissue. The most significant response of adult brain to radiation damage is induction of apoptosis. The adult mammalian subventricular zone (SVZ) of the brain lateral ventricles (LV) and their subsequent lateral ventricular extension, the rostral migratory stream (RMS), is one of the few areas, which retains the ability to generate new neurons and glial cells throughout life. Taking into account the fact, that ionizing radiation is one of the strongest exogenous factors affecting cell proliferation, the aim of the present study was to investigate the occurrence of radiation-induced apoptosis in this neurogenic region. Adult male Wistar rats were investigated 1, 5 or 10 days after single whole-body gamma irradiation with the dose of 3 Gy. Apoptotic cell death was determined by in situ labelling of DNA nick ends (TUNEL) and fluorescence microscopy evaluation of TUNEL-positive cells. Considerable increase of apoptotic TUNEL-positive cells was observed 24 hrs after irradiation in caudal parts of RMS; i.e. in the vertical arm and elbow of RMS. Initial increase was followed by strong reduction of apoptosis in the RMS and by secondary over-accumulation of apoptotic cells in the animals that survived ten days after exposure. Results showed, that the proliferating population of cells, arisen in SVZ are highly sensitive to radiation-induced apoptosis. This observation should have implications for clinical radiotherapy to avoid complications in therapeutic brain irradiation.

Quantitative comparison of angiogenesis and lymphangiogenesis in cutaneous lichen planus and psoriasis: Immunohistochemical assessment

Recent experimental studies revealed that angiogenesis and lymphangiogenesis are closely related to chronic inflammation. The present study aims to evaluate quantitative changes of blood and lymphatic microcirculatory beds in cutaneous lichen planus (CLP) and psoriatic lesions using immunohistochemical analysis with antibodies to CD34, D2-40 and VEGF. Morphometric software was used to determine the area of blood and lymphatic vessels (BVA and LVA) and also the VEGF positive area. Statistical analysis of these parameters confirmed a significant enlargement of both the blood and lymphatic microcirculatory beds in psoriatic and CLP lesions. BVA in CLP lesions was increased by 56% however this augmentation was not as great as in psoriatic lesions where BVA was increased by 123%. Interestingly, LVA in psoriatic and CLP lesions was increased equally by 85%. The strongest VEGF expression was detected in psoriatic lesions, with lower, but still significant, overexpression in CLP lesions. VEGF-C was significantly increased in both psoriatic and CLP lesions in comparable level. Noticeably higher VEGF and VEGF-C expression was observed in the epidermis than in the dermis. Finally, our results indicate that the level of angiogenesis is considerably greater in psoriatic lesions than in CLP lesions, but the level of lymphangiogenesis is equal in both psoriatic and CLP lesions.

Quantitative immunohistochemical assessment of blood and lymphatic microcirculation in cutaneous lichen planus lesions.

Latest advances have brought to light the hypothesis that angiogenesis and lymphangiogenesis are tightly connected to some chronic inflammatory diseases. The present study focuses on immunohistochemical assessment of the quantitative changes in the blood and lymphatic microcirculatory bed in common chronic dermatosis - cutaneous lichen planus. Double immunohistochemistry with CD34 and podoplanin antibodies was used to detect blood and lymphatic endothelium, while anti-human VEGF was used for the observation of a key angiogenesis and lymphangiogenesis inducer. Morphometric analysis was performed with QuickPhoto Micro image analysis software. Results confirmed statistically significant enlargement of both the blood and lymphatic microcirculatory beds. Compared to healthy skin, cutaneous lichen planus lesions revealed 1.6 times enlarged blood microcirculatory bed and 1.8 times enlarged lymphatic microcirculatory bed. Vascular endothelial growth factor (VEGF) expression in lesional skin was significantly higher in the epidermis (19.1 times increase) than in the dermis (10.3 times increase). These findings indicate a tight association of angiogenesis and lymphangiogenesis with the pathogenesis of cutaneous lichen planus.

Microvascular changes in relation to inflammation and epidermal hyperplasia in chronic cutaneous lesions of psoriasis vulgaris.

Epidermal proliferation, inflammatory changes and microvascular augmentation are prominent features of chronic cutaneous psoriatic lesions. The objective of this study was the investigation of blood and lymphatic microvascular changes in relation to epidermal changes and inflammatory infiltration in dermis. Immunohistochemical analysis with antibodies to CD34, podoplanin, vascular endothelial growth factors - A and C (VEGF-A and C) and morphometric software were used for quantification of the following parameters: blood and lymphatic vessel area (BVA and LVA), VEGF - A and VEGF-C positive area, inflammatory cell infiltration in dermis (CIA) and epidermal area (EA). In comparison to healthy skin psoriatic lesions showed remarkable elevation of all measured parameters with the following average increase: BVA (2.8-times increased), LVA (2.6-times increased), VEGF-A and VEGF-C area (in epidermis 29-times and 19- times increased, in dermis 25-times and 15- times increased, respectively ), and EA (3-times increased). Statistical analysis revealed significant positive correlation between CIA and EA in psoriatic samples. Blood vessels area and VEGF - A expression in epidermis showed mild positive correlation with epidermal hyperplasia and weak positive correlation with dermal inflammatory infiltration. VEGF - A expression in epidermis also significantly correlated with blood vessels area. As for the lymphatic microcirculation we found a statistically significant positive correlation between lymphatic vessels area and the cellular infiltration in dermis but only weak correlation with epidermal hyperplasia. We hypothesize that angiogenesis in psoriasis is to a greater extent responding to epidermal hyperplasia and in a lesser way to inflammatory infiltration in dermis. However, lymphangiogenesis is significantly related to dermal inflammatory infiltration.