Dietary factors that affect carotenoid bioavailability

Carotenoids are thought to contribute to the beneficial effects of increased vegetable consumption. To better understand the potential benefits of carotenoids, we investigated the bioavailability of carotenoids from vegetables and dietary factors which might influence carotenoid bioavailability.In a four weeks intervention trial, we found that the increases in plasma concentrations ofβ-carotene and lutein after consumption of a high vegetable diet were 14% and 67%, respectively, of those after consumption of the same amount of carotenoids, supplied in their purified form. In another study, it appeared that the bioavailability ofβ-carotene was particularly low from spinach. Broccoli and green peas were more effective in enhancing plasma concentrations ofβ-carotene after four days consumption (relative bioavailability ca. 3%, 74% and 96% for spinach, broccoli and green peas, respectively). Disruption of the vegetable matrix by mechanical homogenisation significantly improved the bioavailability of lutein from spinach by 14% and of lycopene from tomatoes by 20 to 60%. One hour additional heating of the tomatoes (100°C) also enhanced the bioavailability of lycopene but this effect lacked significance.Carotenoids are absorbed in association with dietary fat and therefore the presence of dietary fat is thought crucial for carotenoid absorption. Four weeks consumption of a full-fat margarine (80% fat), supplemented withα-carotene andβ-carotene, effectively enhanced blood concentrations of these carotenoids. In a further study, we found that in healthy adult volunteers, only a small amount of fat (i.e. 3-5 g per meal) was sufficient to ensure uptake ofα-carotene andβ-carotene. For lutein supplied as lutein esters, however, the amount of fat required for optimal uptake was greater. Daily consumption of an unabsorbable fat replacer, sucrose polyester, with the main meal for four weeks, significantly reduced the bioavailability of carotenoids. Plasma concentrations ofβ-carotene and lycopene were reduced by 20% and 38% if 3 g/d sucrose polyester was consumed.Interaction among carotenoids appeared to interfere with carotenoid bioavailability in some but not all cases. Simultaneous ingestion ofα-carotene andβ-carotene did not affect the bioavailability ofβ-carotene whereas four weeks supplementation withβ-carotene and lutein significantly reduced the plasma concentration of lycopene by 39%.In conclusion, the type of food matrix in which carotenoids are located largely determines their bioavailability. Processing, such as mechanical homogenisation or heat treatment, has the potential to enhance the bioavailability of carotenoids from vegetables. The amount of dietary fat needed to ensure carotenoid absorption seems low, although it depends on the physico-chemical characteristics of the carotenoids ingested. Unabsorbable, fat-soluble compounds reduce carotenoid absorption and interaction among carotenoids may also result in a reduced carotenoid bioavailability.Research into the functional benefits of carotenoids should consider the fact that the bioavailability ofβ-carotene in particular is one order of magnitude higher when provided as pure compound added to foods than when naturally present in foods.</p

AB ve Türkiye Politikaları Ekseninde Kobi'ler ve Kurumsal Sosyal Sorumluluk

Türkiye’nin Onuncu Kalkınma Planı’nda (2014-2018) ve Avrupa Komisyonu’nun 2020 planında KOBİ’lerin rekabet güçlerinin artırılarak ekonomik büyümeye katkısının yükseltilmesi temel stratejik hedef olarak tanımlanmaktadır. Buna göre KOBİ’lerin akıllı, sürdürülebilir ve kapsayıcı büyüme gerçekleştirmeleri, yani kurumsal sosyal sorumluluğu iş süreçlerinin parçası haline getirmeleri gerekmektedir. Bu çalışma akıllı, sürdürülebilir ve kapsayıcı kalkınma ile KSS arasındaki bağları Avrupa’daki ve Türkiye’deki idari, sektörel ve akademik raporların karşılaştırmalı bir analizi ile ortaya koymaya çalışmaktadır. KSS hedeflerine ulaşmak için KOBİ’lerin KSS anlayışlarının, potansiyellerinin, paydaşların rollerinin ve AB hedeflerinin iyi anlaşılması gerekmektedir. KOBİ’lerin sosyal sorumluluklarının kalkınma ve ekonomik büyüme ile olan ilişkisine yönelik araştırmaların gelişmesi kuramsal ve kavramsal çerçevenin kurulması ile mümkündür. Paydaş yönetimi ve sistem kuramı yaklaşımlarını birleştiren bu kuramsal makale ile iletişim yönetimi, kamu ve işletme yönetimi disiplinlerinde geliştirilecek saha çalışmalarının önünün açılması amaçlanmaktadır

Control surface wettability with nanoparticles from phase-change materials

The wetting state of surfaces can be controlled physically from the highly hydrophobic to hydrophilic states using the amorphous-to-crystalline phase transition of Ge2Sb2Te5 (GST) nanoparticles as surfactant. Indeed, contact angle measurements show that by increasing the surface coverage of the amorphous nanoparticles the contact angle increases to high values ∼140°, close to the superhydrophobic limit. However, for crystallized nanoparticle assemblies after thermal annealing, the contact angle decreases down to ∼40° (significantly lower than that of the bare substrate) leading to an increased hydrophilicity. Moreover, the wettability changes are also manifested on the capillary adhesion forces by being stronger for the crystallized GST state

Sphingosine 1-phosphate receptor 5 mediates the immune quiescence of the human brain endothelial barrier

BACKGROUND: The sphingosine 1-phosphate (S1P) receptor modulator FTY720P (Gilenya®) potently reduces relapse rate and lesion activity in the neuroinflammatory disorder multiple sclerosis. Although most of its efficacy has been shown to be related to immunosuppression through the induction of lymphopenia, it has been suggested that a number of its beneficial effects are related to altered endothelial and blood–brain barrier (BBB) functionality. However, to date it remains unknown whether brain endothelial S1P receptors are involved in the maintenance of the function of the BBB thereby mediating immune quiescence of the brain. Here we demonstrate that the brain endothelial receptor S1P(5) largely contributes to the maintenance of brain endothelial barrier function. METHODS: We analyzed the expression of S1P(5) in human post-mortem tissues using immunohistochemistry. The function of S1P(5) at the BBB was assessed in cultured human brain endothelial cells (ECs) using agonists and lentivirus-mediated knockdown of S1P(5). Subsequent analyses of different aspects of the brain EC barrier included the formation of a tight barrier, the expression of BBB proteins and markers of inflammation and monocyte transmigration. RESULTS: We show that activation of S1P(5) on cultured human brain ECs by a selective agonist elicits enhanced barrier integrity and reduced transendothelial migration of monocytes in vitro. These results were corroborated by genetically silencing S1P(5) in brain ECs. Interestingly, functional studies with these cells revealed that S1P(5) strongly contributes to brain EC barrier function and underlies the expression of specific BBB endothelial characteristics such as tight junctions and permeability. In addition, S1P(5) maintains the immunoquiescent state of brain ECs with low expression levels of leukocyte adhesion molecules and inflammatory chemokines and cytokines through lowering the activation of the transcription factor NFκB. CONCLUSION: Our findings demonstrate that S1P(5) in brain ECs contributes to optimal barrier formation and maintenance of immune quiescence of the barrier endothelium

MicroRNAs regulate human brain endothelial cell-barrier function in inflammation: implications for multiple sclerosis.

Blood-brain barrier (BBB) dysfunction is a major hallmark of many neurological diseases, including multiple sclerosis (MS). Using a genomics approach, we defined a microRNA signature that is diminished at the BBB of MS patients. In particular, miR-125a-5p is a key regulator of brain endothelial tightness and immune cell efflux. Our findings suggest that repair of a disturbed BBB through microRNAs may represent a novel avenue for effective treatment of MS