Sphingomyelin (SM) levels in the circulation correlate positively with atherosclerosis burden. SM is a ubiquitous component of human diets, but it is unclear if dietary SM increases circulating SM levels. Dietary choline increases atherosclerosis by raising circulating trimethylamine N-oxide (TMAO) levels in mice and humans. As SM has a choline head group, we ask in this study if dietary SM accelerates atherosclerotic lesion development by increasing circulating SM and TMAO levels. Three studies were performed: (Study 1) C57BL/6 mice were maintained on a high fat diet with or without SM supplementation for 4 weeks prior to quantification of serum TMAO and SM levels; (Study 2) atherosclerosis was studied in apoE^-/- mice after 16 weeks of a high fat diet without or with SM supplementation and (Study 3) apoE^-/- mice were maintained on a chow diet for 19 weeks without or with SM supplementation and antibiotic treatment prior to quantification of atherosclerotic lesions and serum TMAO and SM levels. SM consumption did not increase circulating SM levels or atherosclerosis in high fat-fed apoE^-/- mice. Serum TMAO levels in C57BL/6 mice were low and had no effect atherosclerosis lesion development. Dietary SM supplementation significantly reduced atherosclerotic lesion area in the aortic arch of chow-fed apoE^-/- mice. This study establishes that dietary SM does not affect circulating SM levels or increase atherosclerosis in high fat-fed apoE^-/- mice, but it is anti-atherogenic in chow-fed apoE^-/- mice.

Lutein is a dietary lipophilic compound with anti-inflammatory properties. We have previously shown that dairy fat can improve the lutein content in spinach smoothies. It is, however, unclear whether fat concentrations and fermentation status in dairy products affect lutein liberation in smoothies. Moreover, plant-based milks vary in fat, protein, and fiber content which may affect lutein dissolution. This study aimed to provide translatable information to consumers by comparing lutein liberation in spinach smoothies made with different dairy or plant-based liquids in domestic settings. The smoothies were digested in vitro, and liberated lutein was measured by high-performance liquid chromatography (HPLC). High-fat and medium-fat cow’s milk, as well as coconut milk with and without additives, were found to significantly improve lutein liberation by 36%, 30%, 25%, and 42%, respectively, compared to blending spinach with water alone. Adjustment models suggested that the effects of cow’s milk and coconut milk were derived from fat and protein, respectively. On the other hand, soymilk with and without additives showed significantly reduced lutein liberation by 40% and 61%, respectively. To summarize, only 4 out of 14 tested liquids increased lutein liberation in spinach smoothies. The results highlight the importance of testing food companions for lipophilic active ingredients.

Background: High intake of fruits and vegetables is generally associated with reduced levels of inflammation. In line with this, plasma levels of carotenoids have shown inverse associations with inflammatory markers, in particular C-reactive protein (CRP) and leukocyte counts. However, it remains unclear to what extent carotenoids are associated with specific leukocyte subsets or other inflammatory markers. This study systematically assessed the inter-relationships among total and individual carotenoids, circulating leukocyte subsets, and soluble inflammatory markers in a middle-aged population. Methods: A subcohort of 1078 subjects, aged 50–64, was recruited from the Swedish CArdioPulmonary bioImage Study (SCAPIS) cohort. Leukocyte subsets were determined by whole blood flow cytometry. Five major carotenoids, namely lutein, β-cryptoxanthin, lycopene, α-carotene and β-carotene, and inflammatory markers including CRP, interleukin (IL)-6 and interleukin-18, matrix metalloproteinase (MMP)-9, and myeloperoxidase (MPO), were measured in plasma. Nutrient intake was estimated by validated food frequency questionnaires. Results: Among leukocyte subsets, only granulocytes showed independent and inverse associations with all carotenoids after adjustment. CRP, IL-18, and MMP-9 exhibited similar inverse relationships with most carotenoids. Mediation analysis revealed that the associations of carotenoids with CRP and MMP-9 were mediated by granulocyte counts. Lutein and β-cryptoxanthin remained independently associated with MMP-9 after accounting for the mediation effects of granulocyte counts. No estimated nutrient intake showed comparable associations with leukocyte subsets or inflammatory markers. Conclusions: To our knowledge, this is the largest population-based study investigating relationships between plasma carotenoids, leukocyte subsets, and soluble inflammatory markers. It provides evidence that low levels of carotenoids in plasma are linked to low-grade chronic inflammation and, furthermore, that this relationship is mediated by granulocyte numbers.

BACKGROUND: Persistent inflammation is linked to poor outcomes in patients with a history of myocardial infarction. The inflammatory state has been associated with activation of neutrophils as well as with regulatory T-cell (T _reg ) deficiency. The role of T _regs in the regulation of neutrophil survival has been postulated recently. Here, we investigated neutrophil apoptosis along with the potential impact of T _regs on neutrophil apoptosis in patients with postmyocardial infarction chronic coronary syndrome, compared with healthy controls. METHODS: Twenty patients and 19 controls were included. Neutrophil apoptosis was assessed after 5-hour culture with or without IL (interleukin)-10, TNF (tumor necrosis factor), or lipopolysaccharide. Neutrophil phenotype was evaluated through flow cytometry analysis of surface receptors (CD66b and CXCR4) and ex vivo release of cytokines and proteins. The ability of T _regs to induce neutrophil apoptosis was examined in autologous neutrophil-T _reg cocultures. RESULTS: Spontaneous neutrophil apoptosis was significantly delayed in patients compared with controls (10.3% versus 19.2%, P =0.025). Also, neutrophils from patients overexpressed CD66b and CXCR4 and were more prone to release proinflammatory mediators. Notably, T _regs induced neutrophil apoptosis in healthy subjects, but not in patients, indicating a loss of T _reg -mediated regulation in the latter. There was no evidence that IL-10 had any influence on neutrophil apoptosis. However, cell-to-cell contact was found essential for T _reg -induced neutrophil apoptosis. CONCLUSIONS: Patients with postmyocardial infarction chronic coronary syndrome display delayed neutrophil apoptosis and a proinflammatory neutrophil phenotype that is resistant to T _reg -mediated apoptosis. Neutrophil dysfunction may contribute to persistent inflammation in patients with postmyocardial infarction chronic coronary syndrome, and as such constitutes a novel therapeutic target.