Plasma Ceramides Pathophysiology, Measurements, Challenges, and Opportunities

Ceramides are a family of lipid molecules, composed of sphingosine and a fatty acid, and transported by lipoproteins (primarily by low-density lipoproteins) in the bloodstream. They are not only structural lipids, but multifunctional and bioactive molecules with key roles in many important cellular pathways, such as inflammatory processes and apoptosis, representing potential biomarkers of cardiometabolic diseases as well as pharmacological targets. Recent data reported ceramide modulation by diet and aerobic exercise, suggesting nutrients and exercise-targeting sphingolipid pathways as a countermeasure, also in combination with other therapies, for risk and progression of chronic disease prevention and health maintenance. In this review, we focus on the available data regarding remarks on ceramide structure and metabolism, their pathophysiologic roles, and the effect of dietary habit and aerobic exercise on ceramide levels. Moreover, advancements and limitations of lipidomic techniques and simplification attempts to overcome difficulties of interpretation and to facilitate practical applications, such as the proposal of scores, are also discussed.

Fructan Structure and Metabolism in Overwintering Plants

In northern regions, annual and perennial overwintering plants such as wheat and temperate grasses accumulate fructan in vegetative tissues as an energy source. This is necessary for the survival of wintering tissues and degrading fructan for regeneration in spring. Other types of wintering plants, including chicory and asparagus, store fructan as a reserve carbohydrate in their roots during winter for shoot- and spear-sprouting in spring. In this review, fructan metabolism in plants during winter is discussed, with a focus on the fructan-degrading enzyme, fructan exohydrolase (FEH). Plant fructan synthase genes were isolated in the 2000s, and FEH genes have been isolated since the cloning of synthase genes. There are many types of FEH in plants with complex-structured fructan, and these FEHs control various kinds of fructan metabolism in growth and survival by different physiological responses. The results of recent studies on the fructan metabolism of plants in winter have shown that changes in fructan contents in wintering plants that are involved in freezing tolerance and snow mold resistance might be largely controlled by regulation of the expressions of genes for fructan synthesis, whereas fructan degradation by FEHs is related to constant energy consumption for survival during winter and rapid sugar supply for regeneration or sprouting of tissues in spring.

Two Origins, Two Functions: The Discovery of Distinct Secretory Ducts Formed during the Primary and Secondary Growth in Kielmeyera

Secretory ducts have been reported for more than 50 families of vascular plants among primary and secondary tissues. A priori, all ducts of a plant are of the same type, and only slight variations in the concentration of their compounds have been reported for few species. However, two types of secretion were observed in primary and secondary tissues of Kielmeyera appariciana, leading us to investigate the possible influence of duct origins on the structure and metabolism of this gland. Kielmeyera appariciana has primary ducts in the cortex and pith and secondary ducts in the phloem. Both ducts are composed of uniseriate epithelium surrounded by a sheath and a lumen formed by a schizogenous process. Despite their similar structure and formation, the primary ducts produce resin, while the secondary ducts produce gum. This is the first report of two types of ducts in the same plant. The distinct origin of the ducts might be related to the metabolic alteration, which likely led to suppression of the biosynthetic pathway of terpenoids and phenolics in the secondary ducts. The functional and evolutionary implications of this innovation are discussed in our study and may be related to the diversification of Kielmeyera and Calophyllaceae in tropical environments.

Histamine

Histamine has at least twenty-three known physiological functions, including playing a prominent role in immunologically mediated inflammation. The structure and metabolism of histamine is discussed, together with the various types of histamine receptors. Histamine plays a role in anaphylaxis, mast cell activation syndromes and mastocytosis and these conditions are relevant to anaesthetic practice. The antihistamine drugs and the H2 receptors agonists are discussed with regard to their role in anaesthesia.

Sex-Specific Associations between Cartilage Structure and Metabolism at Rest and Acutely Following Walking and Drop-Landing

Objective Cartilage health is thought to be dependent on the relationship between mechanics, structure, and metabolism, rather than these individual components in isolation. Due to sex differences in cartilage health, there is need to determine if the relationships between these cartilage components separately for males and females. Therefore, we sought to determine the sex-specific associations between cartilage structure and metabolism at rest and their acute response following walking and drop-landing in healthy individuals. Design A cartilage ultrasound assessment and an ante-cubital blood draw were performed before and after walking and drop-landing conditions in 20 males and 20 females. Cartilage structure was assessed via medial and lateral femoral cartilage cross-sectional area. Cartilage metabolism was quantified with serum cartilage oligomeric matrix protein (COMP) concentration. Percent change scores from pre- to postloading were used to calculate acute alterations in cross-sectional area and COMP. Correlational analyses were used to assess the association between cartilage structure and metabolism measures separately for males and females. Results In females, greater resting COMP concentration was associated with less cartilage cross-sectional area in the medial(ρ = −0.50, P = 0.03) and lateral (ρ = −0.69, P = 0.001) femur. Resting cartilage measures were not associated among males. Following walking and drop-landing, percent change scores in cartilage structure and metabolism were not associated. Conclusions This study highlights that, in females, thinner anterior femoral cartilage is associated with greater resting serum COMP concentrations, a biomarker often linked to cartilage breakdown. Future studies into the relationships between various cartilage components should consider sex-specific analyses as these relationships are sex dependent.

Bioactive Compounds and Metabolites from Grapes and Red Wine in Breast Cancer Chemoprevention and Therapy

Phytochemicals and their metabolites are not considered essential nutrients in humans, although an increasing number of well-conducted studies are linking their higher intake with a lower incidence of non-communicable diseases, including cancer. This review summarizes the current findings concerning the molecular mechanisms of bioactive compounds from grapes and red wine and their metabolites on breast cancer—the most commonly occurring cancer in women—chemoprevention and treatment. Flavonoid compounds like flavonols, monomeric catechins, proanthocyanidins, anthocyanins, anthocyanidins and non-flavonoid phenolic compounds, such as resveratrol, as well as their metabolites, are discussed with respect to structure and metabolism/bioavailability. In addition, a broad discussion regarding in vitro, in vivo and clinical trials about the chemoprevention and therapy using these molecules is presented.