Dual effects of extra virgin olive oil in acute wounds.

Extra virgin olive oil (EVOO) has proved beneficial effects in skin wound healing of chronic lesions; however, the effects of EVOO in acute wounds are not completely understood. This study investigated the effects of short-term and long-term administration of a diet rich in EVOO on acute wound healing. To check this, mice were fed with a diet rich in EVOO for 1 week (short term), 1 month, or 3 months (long term). The control group received a standard diet. Mouse macrophages were treated in vitro with EVOO or hydroxytyrosol (HT), which is the main EVOO polyphenol. Short-term administration of an EVOO rich diet in vivo increased lipid peroxidation and mRNA levels of pro-inflammatory cytokine levels and impaired acute wound closure. In contrast, long-term administration of an EVOO rich diet resulted in increased mRNA levels of anti-inflammatory cytokines and enhanced acute wound closure. In both in vivo and in vitro assays, the administration of EVOO or HT resulted in a predominantly anti-inflammatory macrophage phenotype. In conclusion, a diet rich in EVOO has a positive effect on acute wound healing that is dependent on the duration of EVOO administration. Short-term EVOO diet supplementation increases oxidative damage and pro-inflammatory responses, which impaired acute wound closure. On the other hand, long-term EVOO supplementation reduces oxidative damage and enhances anti-inflammatory responses, which improved acute wound closure. The effects of EVOO on oxidation and inflammation in acute wounds are linked to the EVOO polyphenol HT.

Chronic psychological stress aggravates psoriasis-like skin inflammation via overactivation of ß2-adrenoceptor and nuclear factor kappa B pathways.

The relationship between psoriasis severity and psychological stress has been described in several studies. However, the mechanism by which chronic stress exacerbates psoriasis is not completely understood. This study aimed at investigating whether chronic psychological stress can aggravate psoriasis-like skin inflammation. Mice were subjected to a restraint stress model and topically treated with imiquimod (IMQ). Differentiated human keratinocytes were treated with high epinephrine levels and IMQ in vitro. Stress aggravated macroscopic features and the increase in epidermal thickness induced by IMQ in mouse skin. The increase in NF-κB and IL-17A expression induced by IMQ was potentiated by chronic stress in mouse skin. The skin of stressed mice treated with IMQ showed higher levels of ß2-adrenergic receptors (ß2-AR). In human keratinocytes, high epinephrine levels exacerbated the increase in the levels of ß2-AR and IL-17A induced by IMQ. ß-AR antagonist reversed the effects of chronic stress in IMQ-induced inflammation both in vivo and in vitro. In conclusion, stress-stimulated overactivation of the ß2-AR and NF-κB pathways potentiates a Th1/Th17 profile leading to an exacerbation of psoriasis.

Dietary olive oil intake aggravates psoriatic skin inflammation in mice via Nrf2 activation and polyunsaturated fatty acid imbalance.

Psoriasis is a chronic inflammatory skin disease, which does not have effective treatment options. However, olive oil has been suggested as an alternative to treat psoriasis, but no study has evaluated the mechanisms involved in the effects of olive oil on psoriasis. Thus, the current study investigated whether olive oil could ameliorate psoriasiform skin inflammation. To test this, mice received topical application of imiquimod to induce inflammation and were treated orally with olive oil. Human immortalized keratinocytes were also treated with imiquimod and olive oil. Epidermal thickness and keratinocyte proliferation were increased in imiquimod-induced lesions of olive-oil-treated animals. In both in vitro and in vivo studies, protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) were elevated following imiquimod and olive oil administration. Inhibition of Nrf2 abolished the increased proliferation of keratinocytes treated with imiquimod and olive oil, demonstrating the role of Nrf2 in olive oil-mediated exacerbation of psoriasiform skin inflammation. In addition, lower levels of linoleic acid and higher levels of oleic acid were observed in imiquimod- and olive-oil-treated animals, which may also contribute to the adverse effects of olive oil on psoriasis. In conclusion, dietary intake of olive oil aggravates the symptoms of psoriatic skin lesions through the overexpression of Nrf2 and an imbalance in oleic and linoleic acids levels, suggesting that a diet rich in olive oil may have significant negative effects on psoriasis.

Olive oil-induced reduction of oxidative damage and inflammation promotes wound healing of pressure ulcers in mice.

BACKGROUND: The overproduction of reactive oxygen species (ROS) and exacerbated inflammatory response are the main events that impair healing of pressure ulcers. Therefore, olive oil may be a good alternative to improve the healing of these chronic lesions due to its anti-inflammatory and antioxidant properties. OBJECTIVE: This study investigated the effect of olive oil administration on wound healing of pressure ulcers in mice. METHODS: Male Swiss mice were daily treated with olive oil or water until euthanasia. One day after the beginning of treatment, two cycles of ischemia-reperfusion by external application of two magnetic plates were performed in skin to induced pressure ulcer formation. RESULTS: The olive oil administration accelerated ROS and nitric oxide (NO) synthesis and reduced oxidative damage in proteins and lipids when compared to water group. The inflammatory cell infiltration, gene tumor necrosis factor-α (TNF-α) expression and protein neutrophil elastase expression were reduced by olive oil administration when compared to water group. The re-epithelialization and blood vessel number were higher in the olive oil group than in the water group. The olive oil administration accelerated protein expression of TNF-α, active transforming growth factor-ß1 and vascular endothelial growth factor-A when compared to water group. The collagen deposition, myofibroblastic differentiation and wound contraction were accelerated by olive oil administration when compared to water group. CONCLUSION: Olive oil administration improves cutaneous wound healing of pressure ulcers in mice through the acceleration of the ROS and NO synthesis, which reduces oxidative damage and inflammation and promotes dermal reconstruction and wound closure.

Seed oil of Joannesia princeps improves cutaneous wound closure in experimental mice.

Joannesia princeps (Cotieira) is a well known medicinal plant in Brazil, however, the therapeutic effects of oil obtained from its seeds have still not been demonstrated. The beneficial effects of J. princeps seed oil on cutaneous wound healing on the back of experimental mice were investigated. An excisional lesion in male Swiss mice (n=20 per group) was topically treated with mineral oil or J. princeps seed oil once a day beginning on the day of lesion until the third day after wounding. Animals were killed and lesions collected after 14 days. Murine skin fibroblast cultures were treated with J. princeps seed oil and fibroblast activity was evaluated. In the in vivo assay, J. princeps seed oil increased wound contraction and migratory tongue length, but reduced neutrophil and macrophage number when compared with the control group. Blood vessel number, collagen deposition, and VEGF levels were increased in treated lesions when compared with control lesions. However, J. princeps seed oil reduced myofibroblast density and carbonyl protein levels when compared with the control group. In the in vitro assay, treatment with J. princeps seed oil increased fibroblast migration and proliferation, but reduced myofibroblastic differentiation in vitro. In conclusion, J. princeps seed oil accelerates wound closure increasing angiogenesis, keratinocyte migration, and fibroblast activity while reducing inflammatory response and oxidative damage.