Significant increases in sphinganine in CONT may reflect increasesd de novo synthesis driven in part by a higher rate of lipolysis following exercise. Exercise increases lipolysis but given obesity related decreases in muscle fatty acid oxidation, a rise in free palmitate following exercise may, in the short-term, favor increased ceramide synthesis. The observed rise in ceramides in CONT may therefore reflect transient increases in fatty acid mobilization. Further training which would result in an increased FAO capacity would be expected to normalize these parameters. Effects of exercise on ceramides were largely blunted when subjects consumed daily nutrient bars, suggesting enhanced muscle FAO by the provision of nutrient substrates missing from a typical American diet. The nutrient bar is enriched in polyphenols and omega-3 fatty acids, known to increase muscle peroxisome proliferator activated receptor coactivator 1 alpha activity and mitochondrial biogenesis, processes which would be expected to improve amino acid and fatty acid catabolism. In support of this mechanism, we also observed significant lowering of non-essential amino acids , serine, proline, aspartate, glutamine, and alanine . Lower NEAA’s may reflect improved substrate utilization and clearance of biomarkers associated with what has been termed the “metabolic gridlock” associated with obesity. Furthermore, because serine is a substrate for synthesis of sphingolipids,black plastic planting pots its decrease may also have contributed to the lack of a rise in ceramide detected among INT participants.

Alternatively, serine mobilization from other sites into plasma may be lessened when ceramide synthesis is not triggered. Although clinical changes in TG, FBG, insulin and lipoproteins were not significant, we observed several significant correlations between changes in the plasma lipidome with changes in TG and physiologically interrelated pro-atherogenic small dense LDL particles . Plasma contains upwards of 200 distinct SPL species distributed across HDL, apoB-containing lipoproteins and albumin, but differential association with the most atherogenic lipoprotein subspecies has not been described. As with baseline correlations, the change to change correlations following the nutrient bar intervention were highly granular with specific ceramide species showing associations with changes in TG. Ceramides with C14:0, C16:0, C24:1 and C26:1 showed positive associations with changes in TG. C14:0 ceramide has been previously been implicated in nonalcoholic fatty liver disease in adolescent children. C16:0 ceramide inhibits mitochondrial FAO, oxidant production, and impairs Complex IV activity. C24:1 ceramide significantly decreased in the INT group. Inhibition of synthesis of very long chain ceramides by deletion of fatty acid elongase 6 protects against hepatic steatosis in high fat diet induced obesity. Very small LDL particles showed a highly specific correlation with C18:1 ceramide . Deletion of ceramide synthase 1 responsible for C18 ceramide synthesis has also been shown to increase mitochondrial FAO and protect against high fat diet induced NAFLD. Interaction between specific ceramide species and small LDL may be involved in the progression from NAFLD to nonalcoholic steatohepatitis .

NASH is not only characterized by high concentrations of small LDL and a lowmean LDL diameter but post hoc analyses from the Pioglitazone vs Vitamin E vs Placebo for the Treatment of Nondiabetic Patients with NASH trial demonstrated that resolution of NASH was associated with an increase in the average LDL particle diameter and decreased small and very small LDL particles. These lipoprotein subspecies parameters worsened in the participants who did not resolve their NASH. Larger LDL particles have improved affinity for LDL receptors and decreased retention in the sub-endothelial glycoprotein matrix, so would be expected to lead to decreased LDL and reduced atherogenesis. These findings collectively suggest that early changes in ceramide species among INT participants signal favorable shifts in lipid metabolism that may precede improvement in traditional clinical biomarkers. In both CONT and INT participants, sphingosine-1-phosphate levels increased, but with S1P levels rising higher among INT participants. A previous study showed that exercise increases plasma S1P levels and decreases erythrocyte ceramide levels and this effect was more evident in untrained subjects. S1P is degraded by sphingosine-1-phosphate lyase . SPL dependent degradation of S1P is terminal step in sphinogolipid degradation critical for regulating the pool size of all sphingolipids. In blood, ~50–70% of S1P is bound to apolipoprotein M within the HDL complex and is important for its reverse cholesterol transport. Decreased S1P bound to HDL is associated with higher risk for coronary artery disease. Although there were no absolute changes in HDL subspecies, quantification of HDL-bound S1P may provide further insights as to whether increases in plasma S1P in our study participants contribute to improved antiatherogenic HDL functions.

Correlation analysis with changes in amino acids showed highly specific associations between changes in citrulline, arginine bio-availability and cystathionine and changes in measures of insulin resistance. Obesity and insulin resistance are associated with increased CRP, increased citrulline and decreased arginine bio-availability in Teens. This may reflect increased nitric oxide demand associated with the inflammatory metabolic stress of insulin resistance. Interestingly in this cohort with high baseline CRP, only change in ornithine correlated with change in CRP. Arginase expression and increased Ornithine/Arginine ratio has been shown to associate with vasculopathies in humans and in animals fed a high fat, high sugar Western diet. The favorable pairwise difference in arginine bio-availabity in the INT vs CONT groups may have contributed to subgroup specific improvement in systolic BP among INT Teens. Insulin sensitizing treatment with metformin plus pioglitazone for 3 months also improves arginine bioavailability in obese subjects with impaired glucose tolerance. Change in Cystathionine was positively associated with change in glucose, insulin, and HOMA. Cysth is part of an alternate redox pathway to NOS, synthesized by cystathionine-beta-synthase via the transsulfuration pathway. The expression of CBS in the liver observed in mice on a high fat diet has been proposed to be a defense mechanism against increased oxidative stress. Decreased Cysth among INT participants may therefore reflect a lower burden of oxidative stress that could lead to improved insulin regulation. Our study is limited by its relatively short observation period and the small sample size that precluded detailed analysis of data stratified by age. However, covariate analysis showed no significant effects of age with either the baseline correlations or with metabolic responses to the bar suggesting the metabolic impact of the nutrient bar intervention is conserved between the age groupings considered. The sample size was insufficient to consider hereditary factors. The findings in this predominantly minority study cohort may therefore not be generalizable. Furthermore, race and ethnicity, BMI and CRP differed by chance between INT and CONT groups although both groups exhibited comparable and considerable baseline CMR risk. The fact that lower total plasma Cers and specifically lower Cer 24:1 are described in persons ofAfrican American ancestry who by chance represented a larger proportion of the CONT group, cannot explain either the differential rise in total Cers among controls, nor the significant lowering of the Cer24:1 species in the INT group only. A larger study will be required to stratify analyses by race,drainage pot ethnicity and other hereditary factors that may affect sphingolipid metabolism to determine if this may have influenced results. In summary, our study has uncovered several granular and unique associations between plasma ceramides and amino acid metabolites with clinical parameters of dyslipidemia, inflammation and insulin resistance. These findings suggest that remediation of essential nutrients typically lacking in western style diets should be considered an essential component of preventive interventions directed towards the alleviation of CMR. In this regard, the metabolomic changes as monitored herein are more sensitive indicators of favorable, but subtle shifts in metabolism. A lack of response in traditional clinical CMR biomarkers does not necessarily reflect a lack of compliance with behavioral interventions. The positive associations between changes in established traditional risk factors and changes in metabolomic biomarkers support the hypothesis that metabolomic biomarkers are sensitive prognostic indicators at the leading edge of response to lifestyle therapy, possibly mediated at the level of mitochondrial function.

Further larger and longer studies are needed to validate whether the changes observed in these analyses will predict and precede future favorable changes in traditional CMR biomarkers and the benefits to weight regulation that can be anticipated with improved metabolism.Blueberries have been widely studied for their high phytonutrient content, particularly phenolic compounds. Dietary polyphenols found in blueberries consist of flavonoids and phenolic acids . Anthocyanins are the pigments responsible for the color of berries and blueberries have one of the highest anthocyanin contents among foods . The individual anthocyanin profile of blueberries is complex and contains 5 of the 6 anthocyanidins commonly present in food: malvidin, cyanidin, delphinidin, petunidin, and peonidin . The glycoside moieties attached to the anthocyanidin are predominantly galactose, arabinose, and glucose , with all combinations of the 5 anthocyanidins and 3 sugars found across blueberry cultivars. Blueberries are also rich in flavonols, with a predominance of quercetin derivatives , and proanthocyanidins, formed by polymerization of catechin and/or epicatechin units . Nonflavonoid phenolic acids are mainly represented by chlorogenic acid, which results from the esterification of caffeic acid with a quinic acid molecule . Blueberry phytochemicals used in the treatment of cells in vitro often consist of a whole extract, delivered as a reconstituted powder, juice, or pomace , concentrated or not. Specific classes of phytochemicals such as polyphenol-rich extracts and phenolic fractions, including anthocyanins, phenolic acids, and proanthocyanidins are prepared using solvent extraction and purified through solid phase extraction.Polyphenols found in blueberries have been shown to contribute to their health benefits . A number of reviews discuss the association between blueberry consumption and cardiovascular health , inflammatory markers , type 2 diabetes, neuroprotection, and ocular health . These claims on the health benefits of blueberry consumption are supported by epidemiological studies , animal studies , and diverse cell culture models . Randomized controlled trials have investigated antioxidant and anti-inflammatory effects of blueberry in the context of hypertension, cardiovascular diseases, arthritis, insulin resistance, and metabolic syndrome and supplemented with doses between 20 and 50 g of wild blueberry powder, equivalent to 1 to 2 cups of fresh blueberries daily for 6 to 16 wk . However, few reported direct modulation of molecular markers via blueberry supplementation, including circulating inflammatory cytokines and adhesion molecules. To complete and extend the body of literature covering the in vivo physiological effects of blueberry feeding, the current review considers mechanisms of action by focusing on in vitro responses to blueberry components. Evaluation of the bio-active potential of berry phytochemicals or extracts often uses cell models , which serve as controlled, simplified systems . Numerous limitations exist regarding cell culture conditions and the artificial environment in which the cells are maintained, because they are not completely representative of the body’s physiology . In general, cells are treated with parent compounds, disregarding potential host and microbial metabolism between consumption and the moment compounds reach the target organ . Cells are also not always treated with amounts representative of physiological concentrations in the body, which can be low due to the limited absorption of polyphenols . They are relatively simple to access and maintain, and provide insights into the cellular mechanisms of the studied compounds . Although blueberry phytochemicals may impact a multitude of health-related mechanisms, we focused on 2 intrinsically related systems , the regulation of which are central to health, and when dysregulated, underlie many disease outcomes. The objective of this narrative review is to discuss observations related to the modulatory role of blueberry phytochemicals on key pathways implicated in systems, and to consider the results from a physiological perspective.Inflammation is the innate immune system reaction to a stimulus generated by pathogens, damaged cells, carcinogens, toxic compounds, changes in concentrations of reactive oxygen species , and some foods or metabolites . In brief, the NF-κB and mitogen-activated protein kinase [MAPK, subdivided into extracellular-signal-regulated kinase , c-Jun Nterminal kinase , and p38] inflammatory pathways are activated following an external stimulus and/or by proinflammatory cytokines . Their activation generates the production of proinflammatory cytokines, including TNF-α, IL-1β, and IL-6, which upon release mobilize immune cells . Abnormal activation of inflammation-associated proteins, including NADPH oxidase , inducible NO synthase , and cyclooxygenase -2 , and failure to resolve the infection or injury can lead to chronic inflammation linked to diseases and cardiometabolic dysfunction. Studies on murine cell lines include the extensively used monocyte/macrophage RAW 264.7 cells and primary bone marrow-derived macrophages that can be readily activated by binding ligand to several toll-like receptors .