Effects of short-term moderate intensity exercise on the serum metabolome in older adults: a pilot randomized controlled trial.

BACKGROUND: We previously reported changes in the serum metabolome associated with impaired myocardial relaxation in an asymptomatic older community cohort. In this prospective parallel-group randomized control pilot trial, we subjected community adults without cardiovascular disease to exercise intervention and evaluated the effects on serum metabolomics. METHODS: Between February 2019 to November 2019, thirty (83% females) middle-aged adults (53 ± 4 years) were randomized with sex stratification to either twelve weeks of moderate-intensity exercise training (Intervention) (n = 15) or Control (n = 15). The Intervention group underwent once-weekly aerobic and strength training sessions for 60 min each in a dedicated cardiac exercise laboratory for twelve weeks (ClinicalTrials.gov: NCT03617653). Serial measurements were taken pre- and post-intervention, including serum sampling for metabolomic analyses. RESULTS: Twenty-nine adults completed the study (Intervention n = 14; Control n = 15). Long-chain acylcarnitine C20:2-OH/C18:2-DC was reduced in the Intervention group by a magnitude of 0.714 but increased in the Control group by a magnitude of 1.742 (mean difference -1.028 age-adjusted p = 0.004). Among Controls, alanine correlated with left ventricular mass index (r = 0.529, age-adjusted p = 0.018) while aspartate correlated with Lateral e' (r = -764, age-adjusted p = 0.016). C20:3 correlated with E/e' ratio fold-change in the Intervention group (r = -0.653, age-adjusted p = 0.004). Among Controls, C20:2/C18:2 (r = 0.795, age-adjusted p = 0.005) and C20:2-OH/C18:2-DC fold-change (r = 0.742, age-adjusted p = 0.030) correlated with change in E/A ratio. CONCLUSIONS: Corresponding relationships between serum metabolites and cardiac function in response to exercise intervention provided pilot observations. Future investigations into cellular fuel oxidation or central carbon metabolism pathways that jointly impact the heart and related metabolic systems may be critical in preventive trials.

Prior studies have found changes in cellular biological processes in both cardiac aging and heart failure suggesting a common underlying mechanism. I has also been shown that exercise in healthy participants can reverse the signs of early cardiac aging. In this experimental study, we examined the effects of exercise on biological markers and cardiac function among healthy community older adults. After twelve weeks of exercise, there were changes in biological components associated with cardiac function. These findings highlight the potential of exercise as a strategy to target biological alterations in early cardiac aging and potentially prevent it.

Characteristics of pulmonary artery strain assessed by cardiovascular magnetic resonance imaging and associations with metabolomic pathways in human ageing.

Background: Pulmonary artery (PA) strain is associated with structural and functional alterations of the vessel and is an independent predictor of cardiovascular events. The relationship of PA strain to metabolomics in participants without cardiovascular disease is unknown. Methods: In the current study, community-based older adults, without known cardiovascular disease, underwent simultaneous cine cardiovascular magnetic resonance (CMR) imaging, clinical examination, and serum sampling. PA global longitudinal strain (GLS) analysis was performed by tracking the change in distance from the PA bifurcation to the pulmonary annular centroid, using standard cine CMR images. Circulating metabolites were measured by cross-sectional targeted metabolomics analysis. Results: Among n = 170 adults (mean age 71 ± 6.3 years old; 79 women), mean values of PA GLS were 16.2 ± 4.4%. PA GLS was significantly associated with age (ß = -0.13, P = 0.017), heart rate (ß = -0.08, P = 0.001), dyslipidemia (ß = -2.37, P = 0.005), and cardiovascular risk factors (ß = -2.49, P = 0.001). Alanine (ß = -0.007, P = 0.01) and proline (ß = -0.0009, P = 0.042) were significantly associated with PA GLS after adjustment for clinical risk factors. Medium and long-chain acylcarnitines were significantly associated with PA GLS (C12, P = 0.027; C12-OH/C10-DC, P = 0.018; C14:2, P = 0.036; C14:1, P = 0.006; C14, P = 0.006; C14-OH/C12-DC, P = 0.027; C16:3, P = 0.019; C16:2, P = 0.006; C16:1, P = 0.001; C16:2-OH, P = 0.016; C16:1-OH/C14:1-DC, P = 0.028; C18:1-OH/C16:1-DC, P = 0.032). Conclusion: By conventional CMR, PA GLS was associated with aging and vascular risk factors among a contemporary cohort of older adults. Metabolic pathways involved in PA stiffness may include gluconeogenesis, collagen synthesis, and fatty acid oxidation.

Longitudinal aortic strain, ventriculo-arterial coupling and fatty acid oxidation: novel insights into human cardiovascular aging.

Aging-induced aortic stiffness has been associated with altered fatty acid metabolism. We studied aortic stiffness using cardiac magnetic resonance (CMR)-assessed ventriculo-arterial coupling (VAC) and novel aortic (AO) global longitudinal strain (GLS) combined with targeted metabolomic profiling. Among community older adults without cardiovascular disease, VAC was calculated as aortic pulse wave velocity (PWV), a marker of arterial stiffness, divided by left ventricular (LV) GLS. AOGLS was the maximum absolute strain measured by tracking the phasic distance between brachiocephalic artery origin and aortic annulus. In 194 subjects (71 ± 8.6 years; 88 women), AOGLS (mean 5.6 ± 2.1%) was associated with PWV (R = -0.3644, p < 0.0001), LVGLS (R = 0.2756, p = 0.0001) and VAC (R = -0.3742, p <0.0001). Stiff aorta denoted by low AOGLS <4.26% (25th percentile) was associated with age (OR 1.13, 95% CI 1.04-1.24, p = 0.007), body mass index (OR 1.12, 95% CI 1.01-1.25, p = 0.03), heart rate (OR 1.04, 95% CI 1.01-1.06, p = 0.011) and metabolites of medium-chain fatty acid oxidation: C8 (OR 1.005, p = 0.026), C10 (OR 1.003, p = 0.036), C12 (OR 1.013, p = 0.028), C12:2-OH/C10:2-DC (OR 1.084, p = 0.032) and C16-OH (OR 0.82, p = 0.006). VAC was associated with changes in long-chain hydroxyl and dicarboxyl carnitines. Multivariable models that included acyl-carnitine metabolites, but not amino acids, significantly increased the discrimination over clinical risk factors for prediction of AOGLS (AUC [area-under-curve] 0.73 to 0.81, p = 0.037) and VAC (AUC 0.78 to 0.87, p = 0.0044). Low AO GLS and high VAC were associated with altered medium-chain and long-chain fatty acid oxidation, respectively, which may identify early metabolic perturbations in aging-associated aortic stiffening. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02791139.

Urine tricarboxylic acid cycle metabolites and risk of end stage kidney disease in patients with type 2 diabetes.

CONTEXT: Metabolites in tricarboxylic acid (TCA) pathway have pleiotropic functions. OBJECTIVE: To study the association between urine TCA cycle metabolites and the risk for chronic kidney disease (CKD) progression in individuals with type 2 diabetes. DESIGN, SETTING AND PARTICIPANTS: A prospective study in a discovery (n = 1826) and a validation (n = 1235) cohort of type 2 diabetes in a regional hospital and a primary care facility. EXPOSURE AND OUTCOME: Urine lactate, pyruvate, citrate, alpha-ketoglutarate, succinate, fumarate and malate were measured by mass spectrometry. CKD progression was defined as a composite of sustained eGFR below 15 ml/min/1.73 m2 , dialysis, renal death or doubling of serum creatinine. RESULTS: During a median of 9.2 (IQR 8.1-9.7) and 4.0 (3.2-5.1) years of follow-up, 213 and 107 renal events were identified. Cox regression suggested that urine lactate, fumarate and malate were associated with an increased risk (adjusted hazard ratio, aHR [95% CI] 1.63 [1.16-2.28], 1.82 [1.17-2.82] and 1.49 [1.05-2.11], per SD), while citrate was associated with a low risk (aHR 0.83 [0.72-0.96] per SD) for the renal outcome after adjustment for cardio-renal risk factors. These findings were reproducible in the validation cohort. Noteworthy, fumarate and citrate were independently associated with the renal outcome after additional adjustment for other metabolites. CONCLUSION: Urine fumarate and citrate predict the risk for progression to ESKD independent of clinical risk factors and other urine metabolites. These two metabolites in TCA cycle pathway may play important roles in the pathophysiological network underpinning progressive loss of kidney function in patients with type 2 diabetes.

Abnormal lactate metabolism is linked to albuminuria and kidney injury in diabetic nephropathy.

Diabetic nephropathy (DN) is characterized by abnormal kidney energy metabolism, but its causes and contributions to DN pathogenesis are not clear. To examine this issue, we carried out targeted metabolomics profiling in a mouse model of DN that develops kidney disease resembling the human disorder. We found a distinct profile of increased lactate levels and impaired energy metabolism in kidneys of mice with DN, and treatment with an angiotensin-receptor blocker (ARB) reduced albuminuria, attenuated kidney pathology and corrected many metabolic abnormalities, restoring levels of lactate toward normal while increasing kidney ATP content. We also found enhanced expression of lactate dehydrogenase isoforms in DN. Expression of both the LdhA and LdhB isoforms were significantly increased in kidneys of mice, and treatment with ARB significantly reduced their expression. Single-cell sequencing studies showed specific up-regulation of LdhA in the proximal tubule, along with enhanced expression of oxidative stress pathways. There was a significant correlation between albuminuria and lactate in mice, and also in a Southeast Asian patient cohort consisting of individuals with type 2 diabetes and impaired kidney function. In the individuals with diabetes, this association was independent of ARB and angiotensin-converting enzyme inhibitor use. Furthermore, urinary lactate levels predicted the clinical outcomes of doubling of serum creatinine or development of kidney failure, and there was a significant correlation between urinary lactate levels and biomarkers of tubular injury and epithelial stress. Thus, we suggest that kidney metabolic disruptions leading to enhanced generation of lactate contribute to the pathogenesis of DN and increased urinary lactate levels may be a potential biomarker for risk of kidney disease progression.

Plasma Tryptophan-Kynurenine Pathway Metabolites and Risk for Progression to End-Stage Kidney Disease in Patients With Type 2 Diabetes.

OBJECTIVE: We sought to study the associations between plasma metabolites in the tryptophan-kynurenine pathway and the risk of progression to end-stage kidney disease (ESKD) in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: Plasma tryptophan, kynurenine, 3-hydroxykynurenine, kynurenic acid, and xanthurenic acid concentrations were measured in discovery (n = 1,915) and replication (n = 346) cohorts. External validation was performed in Chronic Renal Insufficiency Cohort (CRIC) participants with diabetes (n = 1,312). The primary outcome was a composite of incident ESKD (progression to estimated glomerular filtration rate [eGFR] <15 mL/min/1.73 m2, sustained dialysis, or renal death). The secondary outcome was annual eGFR decline. RESULTS: In the discovery cohort, tryptophan was inversely associated with risk for ESKD, and kynurenine-to-tryptophan ratio (KTR) was positively associated with risk for ESKD after adjustment for clinical risk factors, including baseline eGFR and albuminuria (adjusted hazard ratios [HRs] 0.62 [95% CI 0.51, 0.75] and 1.48 [1.20, 1.84] per 1 SD). High levels of kynurenic acid and xanthurenic acid were associated with low risks of ESKD (0.74 [0.60, 0.91] and 0.74 [0.60, 0.91]). Consistently, high levels of tryptophan, kynurenic acid, and xanthurenic acid were independently associated with a slower eGFR decline, while a high KTR was predictive of a faster eGFR decline. Similar outcomes were obtained in the replication cohort. Furthermore, the inverse association between kynurenic acid and risk of ESKD was externally validated in CRIC participants with diabetes (adjusted HR 0.78 [0.65, 0.93]). CONCLUSIONS: Accelerated catabolism of tryptophan in the kynurenine pathway may be involved in progressive loss of kidney function. However, shunting the kynurenine pathway toward the kynurenic acid branch may potentially slow renal progression.

Lipidomics Workflow for Analyzing Lipid Profiles Using Multiple Reaction Monitoring (MRM) in Liver Homogenate of Mice with Non-alcoholic Steatohepatitis (NASH).

Non-alcoholic steatohepatitis (NASH) is a condition characterized by inflammation and hepatic injury/fibrosis caused by the accumulation of ectopic fats in the liver. Recent advances in lipidomics have allowed the identification and characterization of lipid species and have revealed signature patterns of various diseases. Here, we describe a lipidomics workflow to assess the lipid profiles of liver homogenates taken from a NASH mouse model. The protocol described below was used to extract and analyze the metabolites from the livers of mice with NASH by liquid chromatography-mass spectrometry (LC-MS); however, it can be applied to other tissue homogenate samples. Using this method, over 1,000 species of lipids from five classes can be analyzed in a single run on the LC-MS. Also, partial elucidation of the identity of neutral lipid (triacylglycerides and diacylglycerides) aliphatic chains can be performed with this simple LC-MS setup. Key features Over 1,000 lipid species (sphingolipids, cholesteryl esters, neutral lipids, phospholipids, fatty acids) are analyzed in one run. Analysis of liver lipids in non-alcoholic steatohepatitis (NASH) mouse model. Normal-phase chromatography coupled to a triple quadrupole mass spectrometer.

DEGS1 -related leukodystrophy: a clinical report and review of literature.

BACKGROUND: Leukodystrophies are a heterogeneous group of disorders affecting the white matter of the central nervous system, with or without affecting the peripheral nervous system. Biallelic variants in DEGS1 , coding for desaturase 1 (Des1) protein, were recently reported to be associated with hypomyelinating leukodystrophy (HLD), a subclass of leukodystrophies where the formation of the myelin sheath is affected. METHODS: Genomic sequencing was performed on our index patient with severe developmental delay, severe failure to thrive, dystonia, seizures, and hypomyelination on brain imaging. Sphingolipid analysis was performed and dihydroceramide/ceramide (dhCer/Cer) ratios were obtained by the measurement of ceramide and dihydroceramide species. RESULTS: A homozygous missense variant was identified in DEGS1 (c.565A > G:p Asn189Asp). The identified DEGS1 variant has been annotated as "conflicting reports of pathogenicity" on ClinVar. Follow-up sphingolipid analysis on our patient showed significantly raised dhCer/Cer and this was consistent with dysfunction of the Des1 protein, providing additional evidence to support the pathogenicity of this variant. CONCLUSION: While rare, pathogenic variants in DEGS1 should be considered in patients with HLD phenotype. To date, 25 patients have been reported across four studies on DEGS1 -related HLD, and, in this report, we summarize the literature. More such reports will enable deeper phenotypic characterization of this disorder.

Gut-brain axis through the lens of gut microbiota and their relationships with Alzheimer's disease pathology: Review and recommendations.

Alzheimer's disease (AD) is a neurodegenerative disorder that affects millions of people worldwide. Growing evidence suggests that the gut microbiome (GM) plays a pivotal role in the pathogenesis of AD through the microbiota-gut-brain axis (MGB). Alterations in GM composition and diversity have been observed in both animal models and in human patients with AD. GM dysbiosis has been implicated in increased intestinal permeability, blood-brain barrier (BBB) impairment, neuroinflammation and the development of hallmarks of AD. Further elucidation of the role of GM in AD could pave way for the development of holistic predictive methods for determining AD risk and progression of disease. Furthermore, accumulating evidence suggests that GM modulation could alleviate adverse symptoms of AD or serve as a preventive measure. In addition, increasing evidence shows that Type 2 Diabetes Mellitus (T2DM) is often comorbid with AD, with common GM alterations and inflammatory response, which could chart the development of GM-related treatment interventions for both diseases. We conclude by exploring the therapeutic potential of GM in alleviating symptoms of AD and in reducing risk. Furthermore, we also propose future directions in AD research, namely fecal microbiota transplantation (FMT) and precision medicine.

The Utility of Amino Acid Metabolites in the Diagnosis of Major Depressive Disorder and Correlations with Depression Severity.

Major depressive disorder (MDD) is a highly prevalent and disabling condition with a high disease burden. There are currently no validated biomarkers for the diagnosis and treatment of MDD. This study assessed serum amino acid metabolite changes between MDD patients and healthy controls (HCs) and their association with disease severity and diagnostic utility. In total, 70 MDD patients and 70 HCs matched in age, gender, and ethnicity were recruited for the study. For amino acid profiling, serum samples were analysed and quantified by liquid chromatography-mass spectrometry (LC-MS). Receiver-operating characteristic (ROC) curves were used to classify putative candidate biomarkers. MDD patients had significantly higher serum levels of glutamic acid, aspartic acid and glycine but lower levels of 3-Hydroxykynurenine; glutamic acid and phenylalanine levels also correlated with depression severity. Combining these four metabolites allowed for accurate discrimination of MDD patients and HCs, with 65.7% of depressed patients and 62.9% of HCs correctly classified. Glutamic acid, aspartic acid, glycine and 3-Hydroxykynurenine may serve as potential diagnostic biomarkers, whereas glutamic acid and phenylalanine may be markers for depression severity. To elucidate the association between these indicators and clinical features, it is necessary to conduct additional studies with larger sample sizes that involve a spectrum of depressive symptomatology.

Adverse cardiovascular and metabolic perturbations among older women: 'fat-craving' hearts.

BACKGROUND: Despite known sex-based differences in cardiovascular aging, differences in aging biology are poorly understood. We hypothesize that circulating metabolites studied cross-sectionally with cardiac aging may be associated with cardiovascular changes that distinguish cardiac aging in women. METHODS: A population-based cohort of community men and women without cardiovascular disease from Singapore underwent detailed clinical and echocardiography examinations. Cross-sectional associations between cardiac functional characteristics and metabolomics profiles were examined. RESULTS: Five hundred sixty-seven adults (48.9% women) participated. Women were younger (72 ± 4.4 years vs 73 ± 4.3 years, p = 0.022), had lower diastolic blood pressures (71 ± 11.0 mmHg vs 76 ± 11.2 mmHg, p < 0.0001, and less likely to have diabetes mellitus (18.0% vs 27.6%, p = 0.013) and smoking (3.8% vs 34.5%, p < 0.001). Body mass indices were similar (24 ± 3.8 kg/m2 vs 24 ± 3.4 kg/m2, p = 0.29), but women had smaller waist circumferences (81 ± 10.1 cm vs 85 ± 9.2 cm, p < 0.001). Women had a significantly higher E/e' ratios (10.9 ± 3.4 vs 9.9 ± 3.3, p = 0.007) and mitral A peak (0.86 ± 0.2 m/s vs 0.79 ± 0.2 m/s, p < 0.001) than men. Among women, lower E/e' ratio was associated with higher levels of C16 (OR 1.019, 95%CI 1.002-1.036, p = 0.029), C16:1 (OR 1.06, 95%CI 1.006-1.118, p = 0.028), serine (OR 1.019, 95%CI 1.002-1.036, p = 0.025), and histidine (OR 1.045, 95%CI 1.013-1.078, p = 0.006). Lower mitral A peak was associated with higher levels of histidine (OR 1.039, 95%CI 1.009-1.070, p = 0.011), isoleucine (OR 1.013, 95%CI 1.004-1.021, p = 0.004), and C20 (OR 1.341, 95%CI 1.067-1.684, p = 0.012). CONCLUSION: Impairments in diastolic functions were more frequent among older women compared to men, despite lower prevalence of vascular risk factors and preserved cardiac structure. Cardiac aging in women correlated with metabolites involved in fatty acid oxidation and tricyclic acid cycle fuelling.

Fasting increases susceptibility to acute myocardial ischaemia/reperfusion injury through a sirtuin-3 mediated increase in fatty acid oxidation.

Fasting increases susceptibility to acute myocardial ischaemia/reperfusion injury (IRI) but the mechanisms are unknown. Here, we investigate the role of the mitochondrial NAD+-dependent deacetylase, Sirtuin-3 (SIRT3), which has been shown to influence fatty acid oxidation and cardiac outcomes, as a potential mediator of this effect. Fasting was shown to shift metabolism from glucose towards fatty acid oxidation. This change in metabolic fuel substrate utilisation increased myocardial infarct size in wild-type (WT), but not SIRT3 heterozygous knock-out (KO) mice. Further analysis revealed SIRT3 KO mice were better adapted to starvation through an improved cardiac efficiency, thus protecting them from acute myocardial IRI. Mitochondria from SIRT3 KO mice were hyperacetylated compared to WT mice which may regulate key metabolic processes controlling glucose and fatty acid utilisation in the heart. Fasting and the associated metabolic switch to fatty acid respiration worsens outcomes in WT hearts, whilst hearts from SIRT3 KO mice are better adapted to oxidising fatty acids, thereby protecting them from acute myocardial IRI.

Dried Blood Spots as Matrix for Evaluation of Valproate Levels and the Immediate and Delayed Metabolomic Changes Induced by Single Valproate Dose Treatment.

The immediate and delayed metabolic changes in rats treated with valproate (VPA), a drug used for the treatment of epilepsy, were profiled. An established approach using dried blood spots (DBS) as sample matrices for gas chromatography/mass spectrometry-based metabolomics profiling was modified using double solvents in the extraction of analytes. With the modified method, some of the previously undetectable metabolites were recovered and subtle differences in the metabolic changes upon exposure to a single dose of VPA between males and female rats were identified. In male rats, changes in 2-hydroxybutyric acid, pipecolic acid, tetratriacontane and stearic acid were found between the control and treatment groups at various time points from 2.5 h up to 24 h. In contrast, such differences were not observed in female rats, which could be caused by the vast inter-individual variations in metabolite levels within the female group. Based on the measured DBS drug concentrations, clearance and apparent volume of distribution of VPA were estimated and the values were found to be comparable to those estimated previously from full blood drug concentrations. The current study indicated that DBS is a powerful tool to monitor drug levels and metabolic changes in response to drug treatment.

Sensitive ex vivo human skin transdermal assay testing method with mass spectrometric analysis for cosmetics application.

BACKGROUND: Cosmetics manufacturers are focused on cosmetic delivery systems into the skin, but the level of diffusion of the systems in the skin tissues is not well understood. The current methods, such as Franz diffusion, assess analyte diffusion in the whole skin or artificial membranes, which has limitations for understanding skin delivery systems. AIMS: Our study aimed to create a transdermal delivery method which is based on dermal-epidermal separation of human skin, allowing us to assess each layer of skin separately for its efficacy. MATERIALS AND METHODS: During the experiment, resveratrol was used as the target analyte by applying it to the skin and then separating it into dermis and epidermis. Each layer is treated individually and subjected to a high-resolution mass spectrometry analysis to detect resveratrol levels. As a result, the efficiency of resveratrol diffusion in the dermal and epidermal layers of the skin can be evaluated. RESULTS: We found that resveratrol was detected in both the dermal and epidermal layers using our method. CONCLUSIONS: Hence, we developed a sensitive method for transdermal delivery testing that can be used to evaluate skin delivery systems for cosmetic or pharmaceutical purposes.

Plasma acylcarnitines as metabolic signatures of declining health-related quality of life measure in community-dwelling older adults: a combined cross-sectional and longitudinal pilot study.

BACKGROUND: Health-related quality of life (HRQoL) measures are predictors of adverse health outcomes in older adults. Studies have demonstrated cross-sectional associations between HRQoL measures and blood-based biochemical markers. Acylcarnitines (ACs) are a class of metabolites generated in the mitochondria and are predictive of multiple geriatric syndromes. Changes in ACs reflect alterations in central carbon metabolic pathways. However, the prospective relationship between plasma acylcarnitines and declining HRQoL has not been examined. This study aimed to investigate both cross-sectional and longitudinal associations of baseline ACs with baseline and declining EuroQol-5 Dimension/ EuroQol Visual Analogue Scale (EQ-5D/ EQ-VAS) in community-dwelling older adults. METHODS: 120 community-dwelling older adults with EQ-5D/ EQ-VAS measurements at baseline and follow-up were included. We quantified ACs at baseline using targeted plasma metabolomics profiling. Multivariate regressions were performed to examine cross-sectional and longitudinal associations between the measures. RESULTS: Cross-sectionally, ACs showed no significant associations with either EQ-5D index or EQ-VAS scores. Longitudinally, multiple baseline short-chain ACs were significantly and inversely associated with declining EQ-5D index score, explaining up to 8.5% of variance in the decline. CONCLUSIONS: Within a cohort of community-dwelling older adults who had high HRQoL at baseline, we showed that short-chain acylcarnitines are independent predictors of declining HRQoL. These findings reveal a novel association between central carbon metabolic pathways and declining HRQoL. Notably, dysregulation in mitochondrial central carbon metabolism could be detected prior to clinically important decline in HRQoL, providing the first evidence of objective biomarkers as novel predictors to monitor HRQoL in non-pharmacological interventions and epidemiology.

Ceramidas Plasmáticas na Estratificação de Risco das Doenças Cardiovasculares / Plasma Ceramides in Cardiovascular Disease Risk Stratification

Resumo A produção de ceramida ocorre em todo o corpo e desempenha um papel importante na manutenção da fisiologia normal. No entanto, os níveis de ceramidas são alterados em estados de doença, principalmente durante o desenvolvimento de diabetes e dislipidemia. A produção de ceramidas também está associada à instabilidade das placas ateroscleróticas. Estudos recentes revelam que pacientes com doença arterial coronariana instável apresentam níveis plasmáticos aumentados de ceramidas (principalmente C16, C18 e C24:1). Atualmente, são consideradas biomarcadores emergentes nas doenças cardiovasculares, sendo utilizadas na predição de instabilidade da placa aterosclerótica e eventos cardiovasculares adversos de forma independente aos fatores de risco tradicionais. Com o objetivo de descrever e discutir o papel das ceramidas na estratificação das doenças cardiovasculares, o desenvolvimento desta revisão narrativa contextualiza a importância desse biomarcador no cenário atual da cardiologia.

Abstract Ceramide production takes place throughout the body and plays a key role in the maintenance of normal physiology. However, ceramide levels are altered during disease states, particularly considering the development of diabetes and dyslipidemia. Ceramide production is also associated with atherosclerotic plaque instability. Recent studies revealed that patients with unstable coronary artery disease (CAD) presented increased plasma ceramide levels (especially C16, C18, and C24:1). These molecules are currently considered emerging biomarkers of cardiovascular diseases (CVD), being used for predicting atherosclerotic plaque instability and adverse cardiovascular events independently from traditional risk factors. With the aim of describing and discussing the role of ceramides in the stratification of cardiovascular diseases, this narrative review contextualizes the importance of this biomarker in the present cardiology scenario.

Thyroid Hormone Decreases Hepatic Steatosis, Inflammation, and Fibrosis in a Dietary Mouse Model of Nonalcoholic Steatohepatitis.

Background: Nonalcoholic steatohepatitis (NASH) is characterized by hepatic steatosis, lobular inflammation, and fibrosis. Thyroid hormone (TH) reduces steatosis; however, the therapeutic effect of TH on NASH-associated inflammation and fibrosis is not known. This study examined the therapeutic effect of TH on hepatic inflammation and fibrosis during NASH and investigated THs molecular actions on autophagy and mitochondrial biogenesis. Methods: HepG2-TRß cells were treated with bovine serum albumin-conjugated palmitic acid (PA) to mimic lipotoxic conditions in vitro. Mice with NASH were established by feeding C57BL/6J mice Western diet with 15% fructose in drinking water for 16 weeks. These mice were administered triiodothyronine (T3)/thyroxine (T4) supplemented in drinking water for the next eight weeks. Results: In cultured HepG2-TRß cells, TH treatment increased mitochondrial respiration and fatty acid oxidation under basal and PA-treated conditions, as well as decreased lipopolysaccharides and PA-stimulated inflammatory and fibrotic responses. In a dietary mouse model of NASH, TH administration decreased hepatic triglyceride content (3.19 ± 0.68 vs. 8.04 ± 0.42 mM/g liver) and hydroxyproline (1.44 ± 0.07 vs. 2.58 ± 0.30 mg/g liver) when compared with mice with untreated NASH. Metabolomics profiling of lipid metabolites showed that mice with NASH had increased triacylglycerol, diacylglycerol, monoacylglycerol, and hepatic cholesterol esters species, and these lipid species were decreased by TH treatment. Mice with NASH also showed decreased autophagic degradation as evidenced by decreased transcription Factor EB and lysosomal protease expression, and accumulation of LC3B-II and p62. TH treatment restored the level of lysosomal proteins and resolved the accumulation of LC3B-II and p62. Impaired mitochondrial biogenesis was also restored by TH. The simultaneous restoration of autophagy and mitochondrial biogenesis by TH increased ß-oxidation of fatty acids. Additionally, the elevated oxidative stress and inflammasome activation in NASH liver were also decreased by TH. Conclusions: In a mouse model of NASH, TH restored autophagy and mitochondrial biogenesis to increase ß-oxidation of fatty acids and to reduce lipotoxicity, oxidative stress, hepatic inflammation, and fibrosis. Activating thyroid hormone receptor in the liver may represent an effective strategy for NASH treatment.

Amino acid profile of skeletal muscle loss in type 2 diabetes: Results from a 7-year longitudinal study in asians.

AIMS: Little is known about pathophysiology of sarcopenia in diabetes. We aimed to study amino acid profile associated with skeletal muscle mass loss longitudinally in Type 2 Diabetes Mellitus (T2DM). METHODS: This is a prospective study of 1140 patients aged 56.6 ± 10.6 years from the SMART2D cohort. Skeletal muscle mass was measured using bio-impedance analysis at baseline and follow-up. Amino acids were measured by mass spectrometry. RESULTS: Over a period of up to 7.9 years, 43.9% experienced skeletal muscle mass loss. Lower baseline valine, leucine and isoleucine levels were associated with decreased skeletal muscle mass index (SMI) with corresponding coefficient 0.251(95 %CI 0.009 to 0.493), 0.298(95 %CI 0.051 to 0.544)) and 0.366(95 %CI 0.131 to 0.600). Higher baseline valine, leucine, isoleucine, alanine and tryptophan levels were associated with reduced odds of muscle mass loss with corresponding odds ratio (OR)0.797 (95 %CI 0.690 to 0.921), 0.825 (95 %CI 0.713 to 0.955), 0.826 (95 %CI 0.718-0.950), 0.847 (95 %CI 0.739-0.969) and 0.835 (95 %CI 0.720-0.979). CONCLUSION: The branched-chain amino acids valine, leucine and isoleucine were positively associated with change in SMI and reduced odds of muscle mass loss longitudinally. Further studies should be conducted to elucidate the pathophysiological mechanisms underlying the relationship between these amino acids and muscle mass loss in T2DM.

Integration of the Cortical Haemodynamic Response Measured by Functional Near-Infrared Spectroscopy and Amino Acid Analysis to Aid in the Diagnosis of Major Depressive Disorder.

BACKGROUND: Major depressive disorder (MDD) is a debilitating condition with a high disease burden and medical comorbidities. There are currently few to no validated biomarkers to guide the diagnosis and treatment of MDD. In the present study, we evaluated the differences between MDD patients and healthy controls (HCs) in terms of cortical haemodynamic responses during a verbal fluency test (VFT) using functional near-infrared spectroscopy (fNIRS) and serum amino acid profiles, and ascertained if these parameters were correlated with clinical characteristics. METHODS: Twenty-five (25) patients with MDD and 25 age-, gender-, and ethnicity-matched HCs were recruited for the study. Real-time monitoring of the haemodynamic response during completion of a VFT was quantified using a 52-channel NIRS system. Serum samples were analysed and quantified by liquid chromatography-mass spectrometry for amino acid profiling. Receiver-operating characteristic (ROC) curves were used to classify potential candidate biomarkers. RESULTS: The MDD patients had lower prefrontal and temporal activation during completion of the VFT than HCs. The MDD patients had lower mean concentrations of oxy-Hb in the left orbitofrontal cortex (OFC), and lower serum histidine levels. When the oxy-haemoglobin response was combined with the histidine concentration, the sensitivity and specificity of results improved significantly from 66.7% to 73.3% and from 65.0% to 90.0% respectively, as compared to results based only on the NIRS response. CONCLUSIONS: These findings demonstrate the use of combination biomarkers to aid in the diagnosis of MDD. This technique could be a useful approach to detect MDD with greater precision, but additional studies are required to validate the methodology.

The Kynurenine Pathway in Acute Kidney Injury and Chronic Kidney Disease.

BACKGROUND: The kynurenine pathway (KP) is the major catabolic pathway for tryptophan degradation. The KP plays an important role as the sole de novo nicotinamide adenine dinucleotide (NAD+) biosynthetic pathway in normal human physiology and functions as a counter-regulatory mechanism to mitigate immune responses during inflammation. Although the KP has been implicated in a variety of disorders including Huntington's disease, seizures, cardiovascular disease, and osteoporosis, its role in renal diseases is seldom discussed. SUMMARY: This review summarizes the roles of the KP and its metabolites in acute kidney injury (AKI) and chronic kidney disease (CKD) based on current literature evidence. Metabolomics studies demonstrated that the KP metabolites were significantly altered in patients and animal models with AKI or CKD. The diagnostic and prognostic values of the KP metabolites in AKI and CKD were highlighted in cross-sectional and longitudinal human observational studies. The biological impact of the KP on the pathophysiology of AKI and CKD has been studied in experimental models of different etiologies. In particular, the activation of the KP was found to confer protection in animal models of glomerulonephritis, and its immunomodulatory mechanism may involve the regulation of T cell subsets such as Th17 and regulatory T cells. Manipulation of the KP to increase NAD+ production or diversion toward specific KP metabolites was also found to be beneficial in animal models of AKI. Key Messages: KP metabolites are reported to be dysregulated in human observational and animal experimental studies of AKI and CKD. In AKI, the magnitude and direction of changes in the KP depend on the etiology of the damage. In CKD, KP metabolites are altered with the onset and progression of CKD all the way to advanced stages of the disease, including uremia and its related vascular complications. The activation of the KP and diversion to specific sub-branches are currently being explored as therapeutic strategies in these diseases, especially with regards to the immunomodulatory effects of certain KP metabolites. Further elucidation of the KP may hold promise for the development of biomarkers and targeted therapies for these kidney diseases.