Olimpio Montero

BACKGROUND: Inflammation and metabolic reprogramming are hallmarks of cardiovascular disorders, wherein myocardiocytes switch from fatty acids to glucose to yield energy. This has also been found in the myocardium of patients with calcific aortic valve disease, a prevalent disease exhibiting features of inflammatory disease that lacks pharmacological treatments. Therefore, we posited that the analysis of proinflammatory and metabolic mechanisms might give cues to disclose therapeutic targets. METHODS: The metabolic analysis of aortic valve interstitial cells (VIC) explanted from human valves was performed by Seahorse real-time cell metabolic analysis, fluxomics using ultra-performance liquid chromatography/mass spectrometry, quantitative polymerase chain reaction, metabolite quantitation, and loss-of-function experiments with gene silencing and pharmacological approaches. Findings were validated in quiescent VIC, 3-dimensional porcine VIC–valve endothelial cell cocultures, as well as in valve leaflets and VIC from human patients. RESULTS: The hyperglycolytic program present in calcific aortic valve disease was replicated in control/nonstenotic VIC by cytokine exposure and enhanced by pathogen-associated molecular patterns. Inflammatory stimuli increased fluxes in glycolysis, tricarboxylic acid cycle, and the pentose phosphate pathway. Inflamed VIC exhibited increased glycolytic ATP production and lactate secretion, as well as changes in redox state and metabolic gene profile, that is, upregulation of glycolytic enzyme expression and downregulation of G6PD (glucose-6-phosphate dehydrogenase), the rate-limiting enzyme of the oxidative phase of pentose phosphate pathway. Notably, these alterations were replicated in quiescent VIC and 3-dimensional VIC–valve endothelial cell cocultures and are observed in diseased valves from patients. Strikingly, metabolic rewiring in control VIC was required for inflammation-triggered calcification and differentiation. A Food and Drug Administration–approved JAK (Janus kinase) inhibitor blunted these changes, whose major drivers are the JAK-STAT (signal transducer and activator of transcription) system, HIF (hypoxia-inducible factor)-1α, and NF-κB (nuclear factor-κB). CONCLUSIONS: Inflammation reprograms VIC metabolism to support calcification by downregulating oxidative phase of pentose phosphate pathway and enhancing glycolytic flux and oxidative stress. These findings parallel the metabolic profile of stenotic VIC and provide novel therapeutic clues.

Background/Objectives: Type 2 diabetes mellitus (T2DM) is a metabolic disease whose importance rises with aging, though it is also looming large in younger populations due to increasing obesity. Its effects may damage renal and heart functioning. Plasma biomarkers of T2DM have been shown through metabolomic studies under different conditions, mainly obesity, but untargeted metabolomic studies on T2DM are lacking for elderly people. Methods: A UPLC-MS-based metabolomic approach was conducted to ascertain potential plasma biomarkers in a cohort older than 65 years. Results: The dipeptide Gly-His, along with diverse lysophosphatidylcholines (LPCs), mainly LPC(14:0) and LPC(20:4), and three gangliosides were found to have different plasma content in T2DM subjects compared to control (non-diabetic) subjects (NT2DM). LPC(20:4) exhibited a gender dependence, with statistically significant differences only in females. Gly-His correlated with MEDAS-14, whereas LPC(14:0) correlated with sugar-rich food consumption. Conclusions: As previously demonstrated for other conditions, mainly obesity, altered lipid metabolism was shown in this study to be a hallmark of T2DM in elderly people also.

Background/Objectives: Type 2 Diabetes Mellitus (DM2) is a metabolic disease whose importance rises with aging. Its effects may damage renal and heart functioning. Plasma biomarkers of DM2 have been shown through metabolomic studies under different conditions, mainly obesity, but untargeted metabolomic studies on DM2 were lacking for elderly people. Methods: A UPLC-MS-based metabolomics approach was conducted to ascertain potential plasma biomarkers in an older than 65 years cohort. Results: the dipeptide Gly-His, along with diverse lysophosphatidylcholines (LPCs), mainly LPC(14:0) and LPC(20:4), as well as three gangliosides, were found to have a different plasma content in DM2 subjects as compared to control (non-diabetic) subjects (NDM2). LPC(20:4) exhibited a gender dependence with statistically significant differences only in females. Gly-His correlated with MEDAS-14, whereas LPC(14:0) did with sugar-rich food consumption. Conclusions: as previously shown for other conditions, mainly obesity, altered lipid metabolism was shown in this study to be a hallmark of DM2 also in elderly people.

Platelet‐activating factor (PAF, 1‐alkyl‐2‐acetyl‐sn‐glycero‐3‐phosphorylcholine) was discovered when the mechanisms involved in the deposition of immune complex in tissues were being scrutinized in the experimental model of rabbit serum sickness. The initial adscription of PAF to IgE‐dependent anaphylaxis was soon extended after disclosing its release from phagocytes stimulated by calcium mobilizing agents, formylated peptides, and phagocytosable particles. This explains why ongoing research in the field turned to the analysis of immune cell types and stimuli involved in PAF production with the purpose of establishing its role in pathology. This was spurred by the identification of the chemical structure of PAF and the enzymic mechanisms involved in its biosynthesis and degradation, which showed commonalities with those involved in eicosanoid production and the Lands' cycle of phospholipid fatty acid remodeling. The reassignment of PAF function in immunopathology is explained by the finding that the most robust mechanisms leading to PAF production are associated with opsonic and non‐opsonic phagocytosis, depending on the cell type. While polymorphonuclear leukocytes exhibit opsonic phagocytosis, monocyte‐derived dendritic cells show a marked preference for non‐opsonic phagocytosis associated with C‐type lectin receptors. This is particularly relevant to the defense against fungal invasion and explains why PAF exerts an autocrine feed‐forwarding mechanism required for the selective expression of some cytokines.

Cytokine expression is fine-tuned by metabolic intermediates, which makes research on immunometabolism suitable to yield drugs with a wider prospect of application than the biological therapies that block proinflammatory cytokines. Switch from oxidative phosphorylation (OXPHOS) to glycolysis has been considered a characteristic feature of activated immune cells. However, some stimuli might enhance both routes concomitantly. The connection between the tricarboxylic acid cycle and cytokine expression was scrutinized in human monocyte-derived dendritic cells stimulated with the fungal surrogate zymosan. Results showed that nucleocytosolic citrate and ATP-citrate lyase activity drove IL1B, IL10, and IL23A expression by yielding acetyl-CoA and oxaloacetate, with the latter one supporting glycolysis and OXPHOS by maintaining cytosolic NAD⁺ and mitochondrial NADH levels through mitochondrial shuttles. Succinate dehydrogenase showed a subunit-specific ability to modulate IL23A and IL10 expression. Succinate dehydrogenase A subunit activity supported cytokine expression through the control of the 2-oxoglutarate/succinate ratio, whereas C and D subunits underpinned cytokine expression by conveying electron flux from complex II to complex III of the electron transport chain. Fatty acids may also fuel the tricarboxylic acid cycle and influence cytokine expression. Overall, these results show that fungal patterns support cytokine expression through a strong boost of glycolysis and OXPHOS supported by the use of pyruvate, citrate, and succinate, along with the compartmentalized NAD(H) redox state maintained by mitochondrial shuttles. Visual Abstract Key Points The TCA cycle intermediates citrate and succinate modulate cytokine expression. SDH subunits exert different effects on IL-1β, IL-10, and IL-23 induction. NAD⁺/NADH redox balance supports cytokine production through mitochondrial shuttles.

Correct assessment of the fatty acyl at the glycerol sn-2 position in triacylglycerol (TAG) analysis by liquid chromatography and mass spectrometry (LC-MS) is challenging. Ammonium hydroxide (NH₄OH) is the preferred choice for the solvent additive for the formation of the ammonium adduct ([M + NH₄]⁺). In this study, the influence of different NH₄OH concentrations in the eluents on TAG adduct formation and fragmentation under LC-MS analysis was assessed. Increasing NH₄OH concentrations delayed the chromatographic elution time according to a power function. The [M + NH₄]⁺ and [M + ACN + NH₄]⁺ adducts (where ACN means acetonitrile) were formed at all ammonium concentrations assayed. [M + ACN + NH₄]⁺ predominated above 18.26 mM [NH₄OH], and the intensity of [M + NH₄]⁺ dropped. TAG fragmentation for fatty acyl release in the MS^E was reduced with increasing [M + ACN + NH₄]⁺ adduct, which suggests that ACN stabilizes the adduct in a way that inhibits the rupture of the ester bonds in TAGs. A linear equation (H_sn-I = a × H_[M+NH4]+, where sn-I refers to the sn position of the glycerol (I = 1, 2, or 3) and H is the peak height) was deduced to quantify the dehydroxydiacylglycerol fragment intensity in relation to [M + NH₄]⁺ intensity in the full scan. This equation had a slope mean value of 0.369 ± 0.058 for the sn-1 and sn-3 positions, and of 0.188 ± 0.007 for the sn-2 position.

The membrane glycerolipids of four phototrophs that were isolated from an edaphic assemblage were determined by UPLC–MS after cultivation in a laboratory growth chamber. Identification was carried out by 18S and 16S rDNA sequencing. The algal species were Klebsormidium flaccidum (Charophyta), Oocystis sp. (Chlorophyta), and Haslea spicula (Bacillariophyta), and the cyanobacterium was Microcoleus vaginatus (Cyanobacteria). The glycerolipid profile of Oocystis sp. was dominated by monogalactosyldiacylglycerol (MGDG) species, with MGDG(18:3/16:4) accounting for 68.6%, whereas MGDG(18:3/16:3) was the most abundant glycerolipid in K. flaccidum (50.1%). A ratio of digalactosyldiacylglycerol (DGDG) species to MGDG species (DGDG/MGDG) was shown to be higher in K. flaccidum (0.26) than in Oocystis sp. (0.14). This ratio increased under high light (HL) as compared to low light (LL) in all the organisms, with its highest value being shown in cyanobacterium (0.38–0.58, LL−HL). High contents of eicosapentaenoic acid (EPA, C20:5) and hexadecenoic acid were observed in the glycerolipids of H. spicula. Similar Fourier transform infrared (FTIR) and Raman spectra were found for K. flaccidum and Oocystis sp. Specific bands at 1629.06 and 1582.78 cm⁻¹ were shown by M. vaginatus in the Raman spectra. Conversely, specific bands in the FTIR spectrum were observed for H. spicula at 1143 and 1744 cm⁻¹. The results of this study point out differences in the membrane lipid composition between species, which likely reflects their different morphology and evolutionary patterns.

This article details a correction to: Albillos SM, Montero O, Calvo S, Solano B, Trejo JM, Cubo E. Can Plasma α-Synuclein Help Us to Differentiate Parkinson’s Disease from Essential Tremor? Tremor and Other Hyperkinetic Movements. 2021; 11(1): 20, pp. 1–8. DOI: https://doi.org/10.5334/tohm.600

Studies have revealed controversial results regarding the diagnostic accuracy of plasma α-synuclein levels in patients with Parkinson’s disease (PD). This study was aimed to analyze the diagnostic accuracy of plasma α-synuclein in PD versus healthy controls and patients with essential tremor (ET). In this cross-sectional study, we included de novo (n = 19) and advanced PD patients [OFF (n = 33), and On (n = 35) states], patients with ET (n = 19), and controls (n = 35). The total plasma α-synuclein levels were determined using an ELISA sandwich method. We performed adjusted multivariate regression analysis to estimate the association of α-synuclein levels with group conditions [controls, ET, and de novo, OFF and ON-PD]. We studied the diagnostic accuracy of plasma α-synuclein using the area under the curve (AUC). The plasma α-synuclein levels were higher in controls compared to PD and ET (p < 0.0001), discriminating de novo PD from controls (AUC = 0.74, 95% CI 0.60–0.89), with a trend towards in advanced PD (OFF state) from ET (AUC = 0.69, 95% CI 0.53–0.84). This is the first study examining and comparing plasma α-synuclein levels in ET vs. PD and controls. Preliminary findings suggest that plasma α-synuclein levels might help to discriminate de novo and advanced PD from controls and ET.