Free radical lipid peroxidation inhibits enzymatic conversion of beta-carotene into vitamin A

Astaxanthin improves osteopenia caused by aldehyde-stress resulting from Aldh2 mutation due to impaired osteoblastogenesis

Aldehyde dehydrogenase 2 (ALDH2) plays major roles in aldehyde detoxification and in the catalysis of amino acids. ALDH2∗2, a dominant-negative transgenic expressing aldehyde dehydrogenase 2 (ALDH2) protein, is produced by a single nucleotide polymorphism (rs671) and is involved in the development of osteoporosis and hip fracture with aging. In a previous study, transgenic mice expressing Aldh2∗2(Aldh2∗2 Tg) osteoblastic cells or acetaldehyde -treated MC3T3-E1 showed impaired osteoblastogenesis and caused osteoporosis [1]. In this study, we demonstrated the effects of astaxanthin for differentiation to osteoblasts of MC3T3-E1 by the addition of acetaldehyde and Aldh2∗2 Tg mesenchymal stem cells in bone marrow. Astaxanthin restores the inhibited osteoblastogenesis by acetaldehyde in MC 3T3-E1 and in bone marrow mesenchymal stem cells of Aldh2∗2 Tg mice. Additionally, astaxanthin administration improved femur bone density in Aldh2∗2 Tg mice. Furthermore, astaxanthin improved cell survival and mitochondrial function in acetaldehyde-treated MC 3T3-E1 cells. Our results suggested that astaxanthin had restorative effects on osteoblast formation and provide new insight into the regulation of osteoporosis and suggest a novel strategy to promote bone formation in osteopenic diseases caused by impaired acetaldehyde metabolism.

Redox status as a metabolic stage, integrating emotional pattern and blood pressure in adolescents

Investigation of emotional sphere and LPO processes in adolescents of both sexes aged 14-17 years suffering from essential hypertension revealed pronounced changes in the emotional status associated with dysregulation in the LPO-antioxidant protection system. The emotional sphere in adolescents with hypertension was characterized by increased anxiety in combination with emotional lability, tendency to depression, and aggressive reactions. The most meaningful parameters describing significant differences between the groups of healthy and hypertensive patients in parameters of LPO-antioxidant protection system were fatty acids with double bonds, antioxidant activity, and retinol. Statistically significant opposite correlations between the emotional status parameters and components of LPO-antioxidant protection system were revealed.

Carotenóides como alternativa contra a hipovitaminose A

A hipovitaminose A acarreta xeroftalmia, cegueira e morte em milhares de crianças no mundo e constitui um dos principais problemas nutricionais de populações de países em desenvolvimento, incluído o Brasil. Embora haja grande disponibilidade de frutas e verduras, fontes de carotenóides no Brasil, a hipovitaminose A constitui um grave problema de saúde pública. A falta de informação da população, no que diz respeito às fontes alimentares e aos fatores que interferem na biodisponibilidade dos carotenóides, citados na literatura, com a "mnemônica" SLAMENGHI são possíveis causas associadas a esta contradição. Os atuais fatores de conversão de carotenóides em retinol são superiores aos antigos fatores, o que pressupõe uma efetividade ainda menor na conversão dos carotenóides na forma ativa da vitamina A e coloca em questão a utilização destes no combate à hipovitaminose A. Esta revisão tem como objetivo relatar o que vem sendo abordado acerca do tema biodisponibilidade e fontes de carotenóides, para possibilitar um melhor posicionamento na utilização dos carotenóides no combate à hipovitaminose A.

Carotenoid bioavailability and bioconversion

The possible role of carotenoids and their metabolites in disease prevention is far from fully understood, because the bioavailabilities of carotenoids are complicated by multiple factors that affect their absorption, breakdown, transport, and storage. Rapid progress in developing sophisticated methodologies, including use of stable-isotope dilution methods, now allows for an accurate determination of the true vitamin A activity of provitamin A carotenoids. The recent identification of specific enzymes, which catalyze the breakdown of beta-carotene as well as nonprovitamin A carotenoids, is providing a better understanding of the functions of carotenoids at the molecular level. The pathways and possible mechanisms of carotenoid breakdown and factors affecting the bioavailability of carotenoids, such as carotenoid type, food matrix, interaction with other carotenoids and other food components, nutritional status, aging, and infection, are discussed in this review.