Iron chelation effects on lipid peroxidation, inflammation and ventricular performance in a rat model of isoproterenol induced acute myocardial stress.

Acute cardiac pathologies represent one of the leading causes of death, while iron metabolism is recognized to be implicated in reactive oxygen species production, lipid peroxidation, and inflammation. The aim of the present study was to assess iron chelation effects in isoproterenol (ISO) induced acute cardiac stress. We divided male Wistar rats into preventive and secondary treatment groups, with the active arm consisting in deferiprone (DFP), a lipid permeable chelator. Mortality of ISO was 10-18.18% in both preventive and secondary groups. We analyzed serum and myocardial tissue parameters of inflammation, iron dynamics, and lipid peroxidation, accompanied by ultramicroscopy, histological, and ultrasound-derived parameters of left ventricular function. Results reveal that ISO-mediated lipid peroxidation and inflammation are alleviated by administration of DFP, with negligible effect on systemic ferroregulation dynamics and global ventricular function (as assessed by ultrasound). DFP administration after cardiovascular stress is associated with a decrease in lipid peroxidation and inflammation, without an improvement in gross left ventricular parameters.

Natural chemopreventive alternatives in oral cancer chemoprevention.

We studied the effect of grape seed extract Burgund Mare (BM) on oral carcinogenesis and compared it with that of curcumin (CU). Wistar rats were divided into six groups (n = 10): 4-nitro-quinoline-1-oxide (4NQO) oral carcinogenesis was induced to groups 1 - 5; groups 2 and 3 received BM and CU respectively during initiation and groups 4 and 5 BM and CU during post-initiation of carcinogenesis; group 6 represented the negative control group. Total malondialdehyde (MDA) and reduced glutathione (GSH) were assayed fluorometrically in oral tissue (gingival, jugal, palatal, lingual mucosa) and serum. Histopathological exam was performed and a dysplasia score given to each oral mucosal lesion. Ki67, cyclin D1, p63, Bcl2 and p53 were immunohistochemically evaluated. BM and CU reduced tissue MDA values elevated by 4NQO (P = 0.000). The difference between CU and BM effect was significant in the initiation (P = 0.02) but not in the post-initiation phase of carcinogenesis (P = 0.58). Tissue GSH levels decreased by 4NQO (P < 0.001) were not significantly modified by BM or CU. Serum MDA levels increased by 4NQO (P = 0.000) were significantly lowered by CU (P = 0.04) and BM (P = 0.04) during initiation and by CU during post-initiation of carcinogenesis (P = 0.01). CU was more potent than BM during post-initiation of carcinogenesis (P = 0.01). Serum GSH lowered by 4NQO (P = 0.55) was significantly decreased by BM and CU (P < 0.012), with no significant difference between groups receiving BM or CU. Moderate dysplasia was the most advanced dysplasia induced and gingival localization the most frequent. Both BM and CU lowered dysplasia scores, with BM being the most efficient during post-initiation of carcinogenesis (P = 0.001). Ki67, cyclin D1, p63, Bcl2 and p53 expression increased with dysplasia scores. BM showed chemopreventive properties during initiation and post-initiation of oral carcinogenesis, reducing local and general oxidative stress and the intensity of dysplasia. During post-initiation of carcinogenesis BM and CU exhibited similar effects.

Photodynamic therapy in melanoma--an update.

Melanoma, a cancer that arises from melanocytes is one of the most unresponsive cancers to known therapies. Several studies showed encouraging results of the efficacy of photodynamic therapy (PDT) using different experimental settings in vitro and in vivo as well as a few clinical reports, suggesting a possible role as an adjuvant therapy in the management of advanced melanoma (stage III and IV). In experimental settings, PDT using different protocols on human and mice melanoma cells induced significant apoptosis, necrosis, tumor growth arrest and prolonged the survival of the animals, but seldom achieved complete remission and/or was followed by recurrence and side effects. Clinical reports showed regression of choroidal melanoma and skin melanoma metastasis following PDT. PDT consists in administration of a photosensitizer, which undergoes excitation after suitable irradiation emitted from a light source and generates singlet oxygen (¹O2) and other cytotoxic oxygen species such as superoxide anion radical (O2·â») and hydroxyl radical (OH·). The antitumor effects result from the combination of direct tumor cell photodamage, destruction of tumor vasculature and activation of an immune response. To increase the effectiveness of PDT in melanoma, the therapy has to overcome the protective mechanisms like pigmentation and increased oxidative stress defense, possibly through inhibition of melanogenesis and melanosome targeted photosensitizers. The optimal protocols for tumor and vascular targeted PDT could destroy melanoma and endothelial tumor cells and activate the immune response, thus increasing the overall efficacy. Combination of PDT with immune stimulation therapies might increase the efficiency in destroying the initial tumor as well as micro metastases and decrease the melanoma relapses.

Possible in vivo mechanisms involved in photodynamic therapy using tetrapyrrolic macrocycles

Photodynamic therapy (PDT) mediated by oxidative stress causes direct tumor cell damage as well as microvascular injury. To improve this treatment new photosensitizers are being synthesized and tested. We evaluated the effects of PDT with 5,10,15,20-tetrakis(4-methoxyphenyl)-porphyrin (TMPP) and its zinc complex (ZnTMPP) on tumor levels of malondialdehyde (MDA), reduced glutathione (GSH) and cytokines, and on the activity of caspase-3 and metalloproteases (MMP-2 and -9) and attempted to correlate them with the histological alterations of tumors in 3-month-old male Wistar rats, 180 ± 20 g, bearing Walker 256 carcinosarcoma. Rats were randomly divided into five groups: group 1, ZnTMPP+irradiation (IR) 10 mg/kg body weight; group 2, TMPP+IR 10 mg/kg body weight; group 3, 5-aminolevulinic acid (5-ALA+IR) 250 mg/kg body weight; group 4, control, no treatment; group 5, only IR. The tumors were irradiated for 15 min with red light (100 J/cm², 10 kHz, 685 nm) 24 h after drug administration. Tumor tissue levels of MDA (1.1 ± 0.7 in ZnTMPP vs 0.1 ± 0.04 nmol/mg protein in control) and TNF-α (43.5 ± 31.2 in ZnTMPP vs 17.3 ± 1.2 pg/mg protein in control) were significantly higher in treated tumors than in controls. Higher caspase-3 activity (1.9 ± 0.9 in TMPP vs 1.1 ± 0.6 OD/mg protein in control) as well as the activation of MMP-2 (P < 0.05) were also observed in tumors. These parameters were correlated (Spearman correlation, P < 0.05) with the histological alterations. These results suggest that PDT activates the innate immune system and that the effects of PDT with TMPP and ZnTMPP are mediated by reactive oxygen species, which induce cell membrane damage and apoptosis.

Possible in vivo mechanisms involved in photodynamic therapy using tetrapyrrolic macrocycles.

Photodynamic therapy (PDT) mediated by oxidative stress causes direct tumor cell damage as well as microvascular injury. To improve this treatment new photosensitizers are being synthesized and tested. We evaluated the effects of PDT with 5,10,15,20-tetrakis(4-methoxyphenyl)-porphyrin (TMPP) and its zinc complex (ZnTMPP) on tumor levels of malondialdehyde (MDA), reduced glutathione (GSH) and cytokines, and on the activity of caspase-3 and metalloproteases (MMP-2 and -9) and attempted to correlate them with the histological alterations of tumors in 3-month-old male Wistar rats, 180 ± 20 g, bearing Walker 256 carcinosarcoma. Rats were randomly divided into five groups: group 1, ZnTMPP+irradiation (IR) 10 mg/kg body weight; group 2, TMPP+IR 10 mg/kg body weight; group 3, 5-aminolevulinic acid (5-ALA+IR) 250 mg/kg body weight; group 4, control, no treatment; group 5, only IR. The tumors were irradiated for 15 min with red light (100 J/cm², 10 kHz, 685 nm) 24 h after drug administration. Tumor tissue levels of MDA (1.1 ± 0.7 in ZnTMPP vs 0.1 ± 0.04 nmol/mg protein in control) and TNF-α (43.5 ± 31.2 in ZnTMPP vs 17.3 ± 1.2 pg/mg protein in control) were significantly higher in treated tumors than in controls. Higher caspase-3 activity (1.9 ± 0.9 in TMPP vs 1.1 ± 0.6 OD/mg protein in control) as well as the activation of MMP-2 (P < 0.05) were also observed in tumors. These parameters were correlated (Spearman correlation, P < 0.05) with the histological alterations. These results suggest that PDT activates the innate immune system and that the effects of PDT with TMPP and ZnTMPP are mediated by reactive oxygen species, which induce cell membrane damage and apoptosis.