Tissue-Specific Landscape of Metabolic Dysregulation during Ageing

The dysregulation of cellular metabolism is a hallmark of ageing. To understand the metabolic changes that occur as a consequence of the ageing process and to find biomarkers for age-related diseases, we conducted metabolomic analyses of the brain, heart, kidney, liver, lung and spleen in young (9–10 weeks) and old (96–104 weeks) wild-type mice [mixed genetic background of 129/J and C57BL/6] using NMR spectroscopy. We found differences in the metabolic fingerprints of all tissues and distinguished several metabolites to be altered in most tissues, suggesting that they may be universal biomarkers of ageing. In addition, we found distinct tissue-clustered sets of metabolites throughout the organism. The associated metabolic changes may reveal novel therapeutic targets for the treatment of ageing and age-related diseases. Moreover, the identified metabolite biomarkers could provide a sensitive molecular read-out to determine the age of biologic tissues and organs and to validate the effectiveness and potential off-target effects of senolytic drug candidates on both a systemic and tissue-specific level

Phosphatidylethanolamine N-Methyltransferase Knockout Modulates Metabolic Changes in Aging Mice

Phospholipid metabolism, including phosphatidylcholine (PC) biosynthesis, is crucial for various biological functions and is associated with longevity. Phosphatidylethanolamine N-methyltransferase (PEMT) is a protein that catalyzes the biosynthesis of PC, the levels of which change in various organs such as the brain and kidneys during aging. However, the role of PEMT for systemic PC supply is not fully understood. To address how PEMT affects aging-associated energy metabolism in tissues responsible for nutrient absorption, lipid storage, and energy consumption, we employed NMR-based metabolomics to study the liver, plasma, intestine (duodenum, jejunum, and ileum), brown/white adipose tissues (BAT and WAT), and skeletal muscle of young (9–10 weeks) and old (91–132 weeks) wild-type (WT) and PEMT knockout (KO) mice. We found that the effect of PEMT-knockout was tissue-specific and age-dependent. A deficiency of PEMT affected the metabolome of all tissues examined, among which the metabolome of BAT from both young and aged KO mice was dramatically changed in comparison to the WT mice, whereas the metabolome of the jejunum was only slightly affected. As for aging, the absence of PEMT increased the divergence of the metabolome during the aging of the liver, WAT, duodenum, and ileum and decreased the impact on skeletal muscle. Overall, our results suggest that PEMT plays a previously underexplored, critical role in both aging and energy metabolism

Metabolomic Profiles of Mouse Tissues Reveal an Interplay between Aging and Energy Metabolism

Energy metabolism, including alterations in energy intake and expenditure, is closely related to aging and longevity. Metabolomics studies have recently unraveled changes in metabolite composition in plasma and tissues during aging and have provided critical information to elucidate the molecular basis of the aging process. However, the metabolic changes in tissues responsible for food intake and lipid storage have remained unexplored. In this study, we aimed to investigate aging-related metabolic alterations in these tissues. To fill this gap, we employed NMR-based metabolomics in several tissues, including different parts of the intestine (duodenum, jejunum, ileum) and brown/white adipose tissues (BAT, WAT), of young (9–10 weeks) and old (96–104 weeks) wild-type (mixed genetic background of 129/J and C57BL/6) mice. We, further, included plasma and skeletal muscle of the same mice to verify previous results. Strikingly, we found that duodenum, jejunum, ileum, and WAT do not metabolically age. In contrast, plasma, skeletal muscle, and BAT show a strong metabolic aging phenotype. Overall, we provide first insights into the metabolic changes of tissues essential for nutrient uptake and lipid storage and have identified biomarkers for metabolites that could be further explored, to study the molecular mechanisms of aging

The anticoagulant effects of ethyl pyruvate in whole blood samples.

BackgroundEthyl pyruvate (EP), the ethyl ester of pyruvate, has proven antiinflammatory and antioxidative properties. Additionally, anticoagulant properties have been suggested recently. EP, therefore, is a potentially antiatherosclerotic drug. We aimed to investigate whether EP possesses antiplatelet and anticoagulant properties particularly in the physiological environment of whole blood.MethodsWe investigated the effects of increasing concentrations of EP on platelet function, on the course of clot development, and on standard coagulation times. Additionally, clot ultrastructure using scanning electron microscopy was analysed.ResultsEP exerted significant antiplatelet actions: i) Impedance aggregometry amplitudes (11.7 ± 3.0 ohm, 0 μg/mL EP) dose dependently decreased (7.8 ± 3.1 ohm, 1000 μg/mL EP; -33.3%). ATP exocytosis (0.87 ± 0.24 nM, 0 μg/mL EP) measured by the luminiscent method dose-dependently decreased (0.56 ± 0.14 nM, 1000 μg/mL; -35.6%). ii) Closure times (104.4 ± 23.8 s, 0 μg/mL EP) using the Platelet function analyzer were dose-dependently prolonged (180.5 ± 82.5 s, 1000 μg/mL EP; +72.9%) using membranes coated with collagen/ADP. iii) Surface coverage (15.9 ± 5.1%, 0 μg/mL EP) dose-dependently decreased (9.0 ± 3.7%, 1000 μg/mL EP; -43.4%) using the Cone and Platelet analyzer. EP also exerted significant anticoagulant actions: Coagulation times (177.9 ± 37.8, 0 μg/mL EP) evaluated by means of thrombelastometry were dose-dependently prolonged (212.8 ± 57.7 s, 1000 μg/mL EP; +19.6%). Activated partial thromboplastin times (31.5 ± 1.8 s, 0 μg/mL EP) were dose-dependently prolonged (35.6 ± 2.3 s, 1000 μg/mL EP; +13.0%). Prothrombin times (0.94 ± 0.02 INR, 0 μg/mL EP) were dose-dependently prolonged (1.09 ± 0.04 INR, 1000 μg/mL EP; +16.0%).ConclusionWe found that EP possesses antiplatelet and anticoagulant properties in whole blood. Together with its proven anti-inflammatory and antioxidative properties, EP is a potentially antiatherogenic drug

Simvastatin Efficiently Lowers Small LDL-IgG Immune Complex Levels: A Therapeutic Quality beyond the Lipid-Lowering Effect

<div><p>We investigated a polyethylene glycol non-precipitable low-density lipoprotein (LDL) subfraction targeted by IgG and the influence of statin therapy on plasma levels of these small LDL-IgG-immune complexes (LDL-IgG-IC). LDL-subfractions were isolated from 6 atherosclerotic subjects and 3 healthy individuals utilizing iodixanol density gradient ultracentrifugation. Cholesterol, apoB and malondialdehyde (MDA) levels were determined in each fraction by enzymatic testing, dissociation-enhanced lanthanide fluorescence immunoassay and high-performance liquid chromatography, respectively. The levels of LDL-IgG-IC were quantified densitometrically following lipid electrophoresis, particle size distribution was assessed with dynamic light scattering and size exclusion chromatography. The influence of simvastatin (40 mg/day for three months) on small LDL-IgG-IC levels and their distribution among LDL-subfractions (salt gradient separation) were investigated in 11 patients with confirmed coronary artery disease (CAD). We demonstrate that the investigated LDL-IgG-IC are small particles present in atherosclerotic patients and healthy subjects. In vitro assembly of LDL-IgG-IC resulted in particle density shifts indicating a composition of one single molecule of IgG per LDL particle. Normalization on cholesterol levels revealed MDA values twice as high for LDL-subfractions rich in small LDL-IgG-IC if compared to dominant LDL-subfractions. Reactivity of affinity purified small LDL-IgG-IC to monoclonal antibody OB/04 indicates a high degree of modified apoB and oxidative modification. Simvastatin therapy studied in the CAD patients significantly lowered LDL levels and to an even higher extent, small LDL-IgG-IC levels without affecting their distribution. In conclusion simvastatin lowers levels of small LDL-IgG-IC more effectively than LDL-cholesterol and LDL-apoB levels in atherosclerotic patients. This antiatherogenic effect may additionally contribute to the known beneficial effects of this drug in the treatment of atherosclerosis.</p></div

Identification of in vitro produced small LDL-IgG-IC by density shift.

<p>Small LDL-IgG-IC were produced by in vitro assembly of LDL-subfraction #8 and an anti-human apoB antibody (IgG). After self-generated iodixanol gradient single-step ultracentrifugation (fractionation step size: 3.0 mm) the cholesterol content was measured in the obtained subfractions and the presence of small LDL-IgG-IC was assessed by DELFIA (<b>A</b>). LDL-IgG-F(ab')₂-IC consisting of an HRP-antibody fragment (targeting the F(ab)₂ fragment of human IgG) and small LDL-IgG-IC were produced by incubation of an LDL-IgG-IC rich subfraction (#11) with the HRP-antibody fragment (antibody/LDL particle ratio of 1:100). After self-generated iodixanol gradient single-step ultracentrifugation fractionation was carried out with a step size of 1.0 mm. The density shift of LDL-IgG-IC (peak to peak difference) due to formation LDL-IgG-F(ab')₂-IC is detected by measurement of HRP activity and immunodetection (dot-blot) of IgG in the control experiment (incubation without HRP-antibody fragment) (<b>B</b>).</p

Simvastatin lowers small LDL-IgG-IC levels more effectively than cholesterol and apoB in patients with CAD.

<p>The reduction of total small LDL-IgG-IC levels is presented as percentage change from baseline for the 6 individual LDL-subfractions. Total amounts of small LDL-IgG-IC per fraction were calculated by conversion of the LDL-IgG-IC DELFIA counts. For each subject and each LDL fraction the baseline value and the value after statin therapy were used to calculate the difference as a percentage (post-statin minus pre-statin). Each bar represents the mean difference of total small LDL-IgG-IC per fraction on a percentage basis (*p < 0.05; **p < 0.01). (<b>A</b>). Comparison of the reduction of LDL-cholesterol, LDL-apoB levels and total small LDL-IgG-IC (average of reduction of LDL-subfractions) expressed as percentage change from baseline. Bars for LDL-cholesterol and LDL-apoB represent the percentage differences (post-statin minus pre-statin) determined in the entire LDL fractions. The reduction of the total amount of small LDL-IgG-IC of LDL is presented as average of the percentage differences calculated for LDL-subfractions 1–6 (shown in Fig 5A). Data represent means ± SD (<b>B</b>).</p