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- Efeitos genómicos do octilmetoxicinamato (OMC) a nível vascularPublication . Lorigo, Margarida Ferreira; Lusquinos, José Ignacio Verde; Oliveira, Maria Elisa Cairrão RodriguesA aplicação tópica de protetores solares contra os efeitos nocivos da radiação ultravioleta é a proteção preferida a nível mundial. Atualmente, o octilmetoxicinamato (OMC) é um dos filtros ultravioleta-B mais utilizado na composição dos protetores solares. Estudos recentes demostraram que o OMC pode comportar-se como um disruptor endócrino, mas a nível vascular apenas um estudo inicou a avaliação dos seus efeitos. Neste sentido, o objetivo geral do presente trabalho consistiu no estudo do efeito do OMC no tónus arterial e na análise dos possíveis mecanismos envolvidos neste efeito. Para atingir este objetivo foram delineados os seguintes objetivos específicos: 1) Realizar com sucesso o isolamento e cultura de células musculares lisas da artéria umbilical humana (HUASMC); 2) Analisar o efeito do OMC em artérias umbilicais humanas (HUA) sem endotélio, e em HUASMC; 3) Analisar possíveis mecanismos envolvidos no efeito do OMC em HUA, principalmente o envolvimento dos nucleótidos cíclicos e dos canais de cálcio. Os resultados demonstraram que o OMC exerce um efeito relaxante arterial rápido (não genómico) e independente de endotélio. Também provoca relaxamento a nível das HUASMC. O mecanismo de ação do OMC pode ser, em parte, semelhante ao dos estrogénios, envolvendo a ativação da guanil ciclase solúvel, com aumento dos níveis de cGMP. Para além disso, este mecanismo não envolve a ativação dos canais de cálcio do tipo L. Estudos adicionais são necessários para compreender melhor o mecanismo de ação do OMC a nível vascular.
- Antioxidants as stabilizers of UV filters: an example for the UV-B filter octylmethoxycinnamatePublication . Lorigo, Margarida; Cairrão, ElisaBackground: Sunlight is one of the main harmful exogenous factors that induce the reactive oxygen species formation. The human skin is the first line of photoprotection against harmful exogenous factors, such as UV radiations. The topical application of sunscreens, containing UV-B filters, is widely used to protect against UV-induced damage. Octylmethoxycinnamate is the world’s most widely used UV-B filter in sunscreens. However, recent studies have demonstrated that this substance is an endocrine disruptor compound and with potential to damage DNA. Thus, the safety of this organic filter is a current concern for human health, and it was urgent to develop new photoprotective strategies. In this sense, due to the potential to neutralize the UV-induced free radicals, the use of antioxidants as UV filter stabilizers presented as a novel promising strategy. Research: The purpose of this review was to assess the use of antioxidants as stabilizers for UV-B filter octylmethoxycinnamate. For this, we discuss the chemical and physical characteristics of UV-B filter octylmethoxycinnamate, emphasizing the stability, photostability, and reactivity of this UV filter. The use of antioxidants in sunscreens will also be addressed, from a perspective of the main characteristics that allowed their use in sunscreen formulations. Then, the concomitant use of both was described from a historical and physical chemical perspective, always emphasizing the advantages and disadvantages of this association. Conclusions: The combination of antioxidants with UV-B filter octylmethoxycinnamate in appropriated formulations represents a viable strategy to protect the human skin against UV-induced damage.
- UV-B Filter Octylmethoxycinnamate Induces Vasorelaxation by Ca2+ Channel Inhibition and Guanylyl Cyclase Activation in Human Umbilical ArteriesPublication . Lorigo, Margarida; Antunes, Carla; Lemos, Manuel C.; Oliveira, J. Martinez de; Granadeiro, Luiza Breitenfeld; Cairrão, ElisaUltraviolet (UV) filters are chemicals widely used in personal care products (PCPs). Due to their effect as endocrine disruptor compounds (EDCs), the toxicity of UV filters is a current concern for human health. EDC exposure may be correlated to cardiovascular diseases (CVD), but to our knowledge, no studies assessed the UV filters effects as human EDCs at the vascular level. Octylmethoxycinnamate (OMC) is the world's most widely used UV-B filter, present in more than 90% of PCPs. Due to its demonstrated multiple hormonal activities in animal models, this substance is also suspected to be a human EDC. The purpose of this study was to assess the rapid/short-term effects of OMC on arterial tonus and analyse its mode of action (MOA). Using human umbilical arteries, the endocrine effects of OMC were evaluated in in vitro (cellular and organ) experiments by planar cell surface area (PCSA) and organ bath, respectively. Our data show that OMC induces a rapid/short-term smooth muscle relaxation acting through an endothelium-independent MOA, which seems to be shared with oestrogens, involving an activation of soluble guanylyl cyclase (sGC) that increases the cyclic guanosine monophosphate (cGMP) intracellular levels and an inhibition of L-type voltage-operated Ca2+ channels (L-Type VOCC).
- Vascular Pathways of Testosterone: Clinical ImplicationsPublication . Lorigo, Margarida; Mariana, Melissa; Oliveira, Nelson; Lemos, Manuel C.; Cairrão, ElisaCardiovascular diseases (CVD) are one of the leading causes of death worldwide. Testosterone (T) is an important sex hormone that triggers several genomic and non-genomic pathways, leading to improvements of several cardiovascular risk factors and quality of life in men. At the vascular level, the key effect of T is the vasorelaxation. This review discusses the molecular pathways and clinical implications of T in the vascular system. Firstly, the mechanisms involved in the T vasodilator effect will be presented. Then, it will be discussed the association of T with the main risks for CVD, namely metabolic syndrome, type 2 diabetes mellitus, obesity, atherosclerosis, dyslipidaemia and hypertension. Several studies have shown a correlation between low T levels and an increased prevalence of several CVD. These observations suggest that T has beneficial effects on the cardiovascular system and that testosterone replacement therapy may become a therapeutic reality for some of these disorders.