Fatty acid profile of phospholipids and sphingomyelin in milk and regulation of sphingomyelin synthesis of mammary glands in cows receiving increasing levels of crushed sunflower seeds.

The objective of this study was to investigate the effect of increasing dietary supplementation of crushed sunflower seed (CSS) in the diet of dairy cows on the fatty acid (FA) composition of phospholipids and sphingomyelin in milk, and on mammary transcription of genes that are important for sphingomyelin de novo synthesis. Four groups of 6 cows received diets supplemented with CSS at 0% (control), or 5, 10, or 15% of dry matter for a 5-wk experimental period. Milk samples and mammary biopsies were collected at the end of the experiment. Phospholipid concentration in milk fat decreased linearly with CSS supplementation. Sphingomyelin concentration in milk fat was unaffected by CSS supplementation. Daily yield of phospholipids decreased linearly with CSS supplementation. Daily yield of sphingomyelin was not significantly affected. The CSS supplementation linearly increased the proportion of monounsaturated FA in milk phospholipids. The major isomer incorporated into phospholipids was C18:1 (n-9 cis), which showed a linear increase with CSS supplementation. The C22:0 proportion in sphingomyelin increased linearly with CSS supplementation and constituted between 15.2 to 25.4% of total FA in sphingomyelin. However, CSS supplementation linearly decreased C23:0 sphingomyelin. Mammary transcription of serine palmitoyl transferase, long chain subunit 1 and subunit 2, the rate-limiting enzymes in ceramide synthesis, showed a linear decrease with increasing CSS supplementation. In conclusion, the data showed that dietary supplementation of CSS linearly increased the proportion of unsaturated FA and monounsaturated FA in milk phospholipids with no effect on phospholipid concentration. In addition, CSS supplementation linearly decreased n-3 polyunsaturated fatty acid proportion in sphingomyelin. The results further showed that mammary transcription of important genes for sphingomyelin de novo synthesis is regulated by lipid supplementation.

Hand eczema and stratum corneum ceramides.

BACKGROUND: Hand eczema (HE) is a multifactorial disease, comprising different aetiological conditions and different morphologies. There are two aetiologically distinct groups of HE recognised: exogenous, such as contact dermatitis (allergic and/or irritant HE) and endogenous, such as the classic hyperkeratotic HE. Differences in the skin barrier properties of these two conditions could theoretically be expected. AIM: To examine whether differences exist in the lipid profile and the susceptibility of the stratum corneum (SC) in patients with allergic/irritant HE and those with hyperkeratotic HE. METHODS: Using cyanoacrylate, SC samples were taken from 23 patients with allergic/irritant HE and 15 with hyperkeratotic HE for lipid analysis by high-performance thin-layer chromatography (HPTLC). Samples were also taken from adjacent, unaffected skin. Severity of HE was assessed by the Hand Eczema Severity Index (HECSI), and skin barrier susceptibility was assessed by measuring transepidermal water loss (TEWL) after a 24-hour patch test with sodium lauryl sulfate (SLS). RESULTS: No statistically significant difference was found between groups for the lipid analysis or for skin susceptibility to SLS. We found a significantly higher HECSI score for hyperkeratotic HE compared with irritant or allergic HE (P = 0.02). CONCLUSIONS: There appears to be no difference in skin barrier between allergic/irritant HE (exogenous eczema) and hyperkeratotic HE (endogenous eczema) with regard to SC lipids or susceptibility to SLS.

Effects of pregnancy on obesity-induced inflammation in a mouse model of fetal programming.

OBJECTIVE: Maternal obesity is associated with increased risk of metabolic dysfunction in the offspring. It is not clear whether it is the metabolic changes or chronic low-grade inflammation in the obese state that causes this metabolic programming. We therefore investigated whether low-grade inflammation was present in obese dams compared with controls dams at gestation day 18 (GD18). METHODS: Female mice were fed either a standard chow diet or a highly palatable obesogenic diet for 6 weeks before conception. Mice were either kileed before mating (n=12 in each group) or on GD18 (n=8 in each group). Blood and tissues were collected for analysis. RESULTS: The obesogenic diet increased body weight and decreased insulin sensitivity before conception, while there was no difference between the groups at GD18. Local inflammation was assayed by macrophage count in adipose tissue (AT) and liver. Macrophage count in the AT was increased significantly by the obesogenic diet, and the hepatic count also showed a tendency to increased macrophage infiltration before gestation. This was further supported by a decreased population of monocytes in the blood of the obese animals, which suggested that monocytes are being recruited from the blood to the liver and AT in the obese animals. Gestation reversed macrophage infiltration, such that obese dams showed a lower AT macrophage count at the end of gestation compared with pre-pregnancy obese mice, and there were no longer a tendency toward increased hepatic macrophage count. Placental macrophage count was also similar in the two groups. CONCLUSION: At GD18, obese dams were found to have similar macrophage infiltration in placenta, AT and liver as lean dams, despite an incipient infiltration before gestation. Thus, the obesity-induced inflammation was reversed during gestation.

Ceramide profile in hypohidrotic ectodermal dysplasia.

BACKGROUND: Hypohidrotic ectodermal dysplasia (HED) is a rare genetic disease. The clinical presentation includes lack of sweating ability, and an often widely spread dermatitis resembling atopic dermatitis (AD). In AD, the skin-barrier defect is partly ascribed to the altered lipid profile in the stratum corneum and partly to mutations of the filaggrin genes. To our knowledge, no data are available about the epidermal lipid profile of HED. AIM: To compare the ceramide profile for patients with HED and AD. METHODS: The ceramide profile and ceramide/cholesterol ratio were compared between patients with HED (n = 7) and patients with AD (n = 21), using cyanoacrylate to take biopsy samples from the stratum corneum. Lipids were extracted from the biopsies and analysed using high-performance thin-layer chromatography. RESULTS: The lipid profiles of HED and AD were similar in distribution, apart from ceramide 1, which was significantly higher in HED (P = 0.04). CONCLUSIONS: The increased ceramide 1 level found in HED compared with AD is known to play a role in the structure of the lipid bilayers. However, further studies are needed to identify the functional significance of these observations and thereby elucidate differences in the skin barrier between HED and AD.

Muscle ceramide content is similar after 3 weeks' consumption of fat or carbohydrate diet in a crossover design in patients with type 2 diabetes.

This study aimed at investigating the effect of prolonged adaptation to fat- or carbohydrate-rich diet on muscle ceramide in type 2 diabetes patients, using a longitudinal crossover study. Eleven type 2 diabetes patients consumed isocaloric fat- or carbohydrate-rich diet for 3 weeks in random order. After each dietary intervention period, muscle glycogen, triacylglycerol and ceramide content and plasma concentrations of insulin, adiponectin, glucose and FFA were determined. Insulin resistance was assessed by HOMA2 calculation. After the dietary period, plasma glucose and insulin, insulin sensitivity, muscle glycogen, triacylglycerol and ceramide content were similar. Plasma adiponectin concentration was significantly higher after fat compared with carbohydrate-rich diet. Results indicated that following fat-rich diet intake muscle ceramide and triacylglycerol concentrations were not different compared with that after carbohydrate-rich diet. Furthermore, plasma adiponectin concentration was higher after fat-rich compared with carbohydrate-rich diet, but insulin sensitivity remained similar despite the major difference in dietary macronutrient composition.

Stratum corneum lipids, skin barrier function and filaggrin mutations in patients with atopic eczema.

BACKGROUND: Prior to the discovery of filaggrin (FLG) mutations, evidence for an impaired skin barrier in atopic dermatitis (AD) has been documented, and changes in ceramide profile, altered skin pH and increased trans-epidermal water loss (TEWL) in patients with AD have been reported. Until now, no studies have analysed stratum corneum (SC) lipids combined with skin barrier parameters in subjects of known FLG genotype. METHODS: A cohort of 49 German individuals genotyped for the most common FLG mutations (R501X, 2282del4) had SC samples taken for lipid analysis by high-performance thin layer chromatography. In addition, TEWL, erythema, skin hydration and pH were measured. In 27 of the 49 individuals, a 24-h irritation patch test with sodium lauryl sulphate was performed. For the analysis, both the AD group and the control group were stratified by FLG mutation status (FLGmut/FLGwt). RESULTS: In the FLGmut AD group, significantly lower levels of ceramide 4 and significantly higher levels of ceramide 7 were observed when compared to both healthy control groups. However, ceramide 7 levels also significantly differed between FLGwt AD and FLGwt controls, as did ceramide 1 levels. No significant differences were observed for ceramide 2, 3, 5 and 6. FLGmut individuals had significantly higher skin pH values than individuals not carrying FLG mutations. Patients with AD with FLG mutations had significantly higher erythema compared to patients with AD without FLG mutations. CONCLUSION: Our results confirm previous observations of altered ceramide levels in AD, which however appear to show no clear relationship with FLG mutations.

Ethnicity and stratum corneum ceramides.

BACKGROUND: The barrier function of the skin is dependent on an optimal composition of the stratum corneum lipids, exemplified by the altered lipid profile in patients with atopic eczema (AE). Differences in the global prevalence of AE point to the environment as an important factor in AE. Studies on filaggrin point to a genetic aspect in AE. The influence of environment and genes needs to be explored. OBJECTIVES: To investigate possible differences in stratum corneum lipids between different healthy ethnicities living in the same environment. METHODS: Healthy participants without any major skin diseases were enrolled in the study. Twenty-five participants of Asian origin (Asians), 18 of African origin (Africans) and 28 of Danish origin (white-skinned), all students at universities in the Copenhagen area of Denmark, had the ceramide profile of their stratum corneum examined using the cyanoacrylate method and analysed using high-performance thin layer chromatography. RESULTS: For the ceramide/cholesterol ratio we found statistically significant differences between groups, with Asians having the highest ratio (P < 0·001 as compared with both white-skinned individuals and Africans), white-skinned individuals having intermediate values, and Africans having the lowest values. No statistically significant differences were found between any of the ceramide subgroups. CONCLUSIONS: We found different ceramide/cholesterol ratios in comparable groups of different ethnicity, pointing to unknown genetic differences.

Validation of cyanoacrylate method for collection of stratum corneum in human skin for lipid analysis.

BACKGROUND AND OBJECTIVE: Lipids in the stratum corneum (SC) are of major importance for the skin barrier function. Many different methods have been used for the collection of SC for the analysis of SC lipids. The objective of the present study was to validate the cyanoacrylate method for the collection of SC in relation to lipid analysis. METHODS: The results of the lipid analysis (ceramide/cholesterol and ceramide profile) of SC samples obtained by the cyanoacrylate method were compared to the results of the lipid analysis of mechanically removed SC samples. The intra- and interindividual variations in lipid composition were assessed when using the cyanoacrylate method, and lipid compositions in cyanoacrylate samples and samples taken from different depths of SC were compared. RESULTS: No statistically significant differences were found between mean values of lipids from the mechanically removed total thickness of the SC and cyanoacrylate samples. With respect to the cyanoacrylate samples, the intraindividual variation was significantly smaller than the interindividual variation, and the results did not indicate a change in lipid profile related to the depth of SC. The results clearly indicate that the cyanoacrylate method used for obtaining SC for lipid analysis is a useful and valid method for the purpose.

High-fat feeding induces mobilization of vitamin C in obese prone rats.

In obesity and dyslipidemia, hydrolysis of triacylglycerol (TAG) into non-esterified fatty acids (NEFAs) may contribute to insulin resistance, and production of oxygenated, bioactive polyunsaturated fatty acids may increase oxidative stress. Here we show that after six weeks of high-fat feeding of obese prone rats (Crl:OP(CD), vitamin C was increased both in liver (P < 0.01) and plasma (P < 0.001), while both TAG (P < 0.01) and NEFA (P < 0.001) were lower than in low-fat fed control rats. Hepatic vitamin C biosynthesis was similar between groups, indicating that a new steady state level was established with a higher vitamin C level adequate for supplying the systemic needs. Glucose and insulin sensitivity were unaffected at this stage. Eventually, the mobilization of vitamin C may be seen as a mechanism to protect the host against insulin resistance.

The effect of maternal Inflammation on foetal programming of metabolic disease.

Maternal obesity during pregnancy increases the child's risk of developing obesity and obesity-related diseases later in life. Key components in foetal programming of metabolic risk remain to be identified; however, chronic low-grade inflammation associated with obesity might be responsible for metabolic imprinting in the offspring. We have therefore surveyed the literature to evaluate the role of maternal obesity-induced inflammation in foetal programming of obesity and related diseases. The literature on this topic is limited, so this review also includes animal models where maternal inflammation is mimicked by single injections with lipopolysaccharide (LPS). An LPS challenge results in an immunological response that resembles the obesity-induced immune profile, although LPS injections provoke a stronger response than the subclinical obesity-associated response. Maternal LPS or cytokine exposures result in increased adiposity and impaired metabolic homeostasis in the offspring, similar to the phenotype observed after exposure to maternal obesity. The cytokine levels might be specifically important for the metabolic imprinting, as cytokines are both transferable from maternal to foetal circulation and have the capability to modulate placental nutrient transfer. However, the immune response associated with obesity is moderate and therefore potentially weakened by the pregnancy-driven immune modulation, dominated by anti-inflammatory Treg and Th2 cells. We know from other low-grade inflammatory diseases, such as rheumatoid arthritis, that pregnancy can improve disease state. If pregnancy is also capable of suppressing the obesity-associated inflammation, the immunological markers might be less likely to affect metabolic programming in the developing foetus than otherwise implied.

Pre-natal undernutrition and post-natal overnutrition are associated with permanent changes in hepatic metabolism markers and fatty acid composition in sheep.

AIM: Determine the impacts of pre- and early-post-natal nutrition on selected markers of hepatic glucose and fat metabolism. METHODS: Twin-bearing ewes were fed 100% (NORM) or 50% (LOW) of protein and energy requirements during the last 6-weeks of gestation. Twin-lambs received either a high-carbohydrate high-fat (HCHF) or conventional (CONV) diet from 3 days to 6 months of age (around puberty), whereafter lambs from the four subgroups were slaughtered (16 males/3 females). Remaining lambs (19 females) were fed a moderate diet and slaughtered at 2 years of age (young adults). RESULTS: Pre-natal LOW nutrition was associated with increased hepatic triglyceride, ceramide and free fatty acid content in adulthood (not observed in lambs), which was accompanied by up-regulated early-stage insulin signalling as reflected by increased INSRß and PI3K-p110 protein expression. The HCHF diet increased hepatic triglyceride content in lambs, associated with down-regulated expressions of energy-metabolism-related genes (GLUT1, PPARα, SREBP1c, PEPCK). These post-natal effects were not observed in adult HCHF sheep, after they had received a moderate (body-fat correcting) diet for 1.5 years. Interestingly, pre-natal LOW nutrition induced permanent alterations in hepatic phospholipids' fatty acid composition. Thus, the amount of linoleic acid (C18 : 2 ∆(9,12)) was significantly increased and composition of rumen-derived fatty acids were altered, indicating changed composition of rumenal microbiota. CONCLUSION: Hepatic insulin signalling and linoleic and microbial-derived fatty acid content in phospholipids are targets of foetal programming induced by late-gestation undernutrition. Future studies are required to explain their cause-effect associations with increased risks of developing hepatic steatosis and insulin insensitivity in adulthood.

Improved glucose tolerance after intensive life style intervention occurs without changes in muscle ceramide or triacylglycerol in morbidly obese subjects.

AIM: This study investigated the effect of a 15-week life style intervention (hypocaloric diet and regular exercise) on glucose tolerance, skeletal muscle lipids and muscle metabolic adaptations in 14 female and 9 male morbidly obese subjects (age: 32.5±2.3 years, body mass index: 46.1±1.9 kg m(-2) ). METHOD: Before and after the life style intervention, an oral glucose tolerance test was performed and a muscle biopsy was obtained in the fasted state. Maximal oxygen uptake was measured by an indirect test. RESULTS: After the intervention, body weight was decreased (P<0.05) by 11±1%, maximal oxygen uptake increased (P<0.05) by 18±5% and glucose tolerance increased (P<0.05) by 12±3%. Muscle glycogen was significantly increased by 47±14%, but muscle ceramide and triacylglycerol content remained completely unchanged. No sex difference was observed for any of these parameters, but during submaximal exercise a marked decrease (P<0.05) of 15±2% in respiratory exchange ratio was seen only in females indicating an enhanced fat oxidation. CONCLUSION: Despite a marked weight loss and an improved aerobic capacity muscle ceramide and triacylglycerol remained unchanged after intensive life style intervention, and muscle lipids hence do not seem to play a major role for the improved glucose tolerance in these morbidly obese subjects. Interestingly, only the females improved fat oxidation during submaximal exercise after the intervention implying the presence of a sex-dependent response to intensive life style adaptation.

Milk-derived GM(3) and GD(3) differentially inhibit dendritic cell maturation and effector functionalities.

Gangliosides are complex glycosphingolipids, which exert immune-modulating effects on various cell types. Ganglioside GD(3) and GM(3) are the predominant gangliosides of human breast milk but during the early phase of lactation, the content of GD(3) decreases while GM(3) increases. The biological value of gangliosides in breast milk has yet to be elucidated but when milk is ingested, dietary gangliosides might conceptually affect immune cells, such as dendritic cells (DCs). In this study, we address the in vitro effect of GD(3) and GM(3) on DC effector functionalities. Treatment of bone marrow-derived DCs with GD(3) before lipopolysaccharide-induced maturation decreased the production of interleukin-6 (IL-6), IL-10, IL-12 and tumor necrosis factor-alpha as well as reduced the alloreactivity in mixed leucocyte reaction (MLR). In contrast, only IL-10 and IL-12 productions were significantly inhibited by GM(3,) and the potency of DCs to activate CD4(+) cells in MLR was unaffected by GM(3). However, both gangliosides suppressed expression of CD40, CD80, CD86 and major histocompatibility complex class II on DCs. Because GD(3) overall inhibits DC functionalities more than GM(3), the immune modulating effect of the ganglioside fraction of breast milk might be more prominent in the commencement of lactation during which the milk contains the most GD(3).

Age-dependent variation in membrane lipid synthesis in leaves of garden pea (Pisum sativum L.).

To study membrane lipid synthesis during the life-span of a dicotyledon leaf, the second oldest leaf of 10-40-d-old plants of garden pea (Pisum sativum L.) was labelled with [1-(14)C]acetate and the distribution of radioactivity between the major membrane lipids was followed for 3 d. In the expanding second oldest leaf of 10-d-old plants, acetate was primarily allocated into phosphatidylcholine (PC) during the first 4 h of labelling. During the following 3 d, labelling of PC decreased and monogalactosyldiacylglycerol (MGDG) became the most radioactive lipid. In the fully expanded second oldest leaf of older plants, acetate was predominantly allocated into phosphatidylglycerol (PG), which remained the major radiolabelled lipid during the 3 d studied. The proportion of radioactivity recovered in MGDG decreased with increasing plant age up to 20 d, suggesting that, in expanded leaves, MGDG is more stable and requires renewal to a lower extent than PG. When the second oldest leaf approached senescence, labelling of MGDG again increased, indicating an increased need for thylakoid repair. The proportion of acetate allocated into phosphatidylethanolamine and free sterols was largest in leaves of 18-26-d-old plants and in the youngest leaves, respectively. Thus, these results demonstrate that the distribution of newly synthesized fatty acids between acyl lipid synthesis in the chloroplast and extraplastidial membranes strongly varies with leaf age, as do the proportion utilized for sterol synthesis. The findings emphasize the importance of defining the developmental stage of the leaf material used when performing studies on leaf lipid metabolism.