GWAS meta-analysis reveals key risk loci in essential tremor pathogenesis.

Essential tremor (ET) is a prevalent neurological disorder with a largely unknown underlying biology. In this genome-wide association study meta-analysis, comprising 16,480 ET cases and 1,936,173 controls from seven datasets, we identify 12 sequence variants at 11 loci. Evaluating mRNA expression, splicing, plasma protein levels, and coding effects, we highlight seven putative causal genes at these loci, including CA3 and CPLX1. CA3 encodes Carbonic Anhydrase III and carbonic anhydrase inhibitors have been shown to decrease tremors. CPLX1, encoding Complexin-1, regulates neurotransmitter release. Through gene-set enrichment analysis, we identify a significant association with specific cell types, including dopaminergic and GABAergic neurons, as well as biological processes like Rho GTPase signaling. Genetic correlation analyses reveals a positive association between ET and Parkinson's disease, depression, and anxiety-related phenotypes. This research uncovers risk loci, enhancing our knowledge of the complex genetics of this common but poorly understood disorder, and highlights CA3 and CPLX1 as potential therapeutic targets.

High-throughput proteomic analysis of chronic inflammatory skin diseases: Psoriasis and atopic dermatitis.

Common characteristics in the pathogenesis of psoriasis (PS) and atopic dermatitis (AD) have been presumed, but only a few studies have clearly supported this. The current aim was to find possible similarities and differences in protein expression patterns between these two major chronic inflammatory skin diseases. High-throughput tandem mass spectrometry proteomic analysis was performed using full thickness skin samples from adult PS patients, AD patients and healthy subjects. We detected a combined total of 3045 proteins in the three study groups. According to principal component analysis, there was significant overlap between the proteomic profiles of PS and AD, and both clearly differed from that of healthy skin. The following validation of selected proteins with western blot analysis showed similar tendencies in expression levels and produced statistically significant results. The expression of periostin (POSTN) was consistently high in AD and very low or undetectable in PS (5% FDR corrected p < 0.001), suggesting POSTN as a potential biomarker to distinguish these diseases. Immunohistochemistry further confirmed higher POSTN expression in AD compared to PS skin. Overall, our findings support the concept that these two chronic skin diseases might share considerably more common mechanisms in pathogenesis than has been suspected thus far.

Apnoea-hypopnoea index of 5†events·h-1 as a metabolomic threshold in patients with sleep complaints.

Background: The apnoea-hypopnoea index (AHI) forms the basis for severity of obstructive sleep apnoea (OSA), a condition expected to reprogramme metabolic pathways in humans. We aimed to identify the AHI breakpoint from which the majority of significant changes in the systemic metabolome of patients with sleep complaints occur. Methods: In a prospective observational study on symptomatic individuals, who underwent polysomnography for the diagnosis of OSA, profiles of 187 metabolites including amino acids, biogenic amines, acylcarnitines, lysophosphatidylcholines, phosphatidylcholines and sphingomyelins were analysed with liquid chromatography mass spectrometry in peripheral blood drawn at three different time points overnight. Comparisons of rank-transformed data using a general linear model for repeated measures after dichotomising the study group at different AHI levels were applied to define the best cut-off based on Cohen's f. Results: 65 subjects were recruited with a median AHI of 15.6 events·h-1. The mean Cohen's f over the metabolites was highest (0.161) at an AHI level of 5 events·h-1 representing the metabolomic threshold. Of the particular between-group differences, eight phosphatidylcholines, nine acylcarnitines and one amino acid (threonine) had significantly lower concentrations in the individuals with an AHI level equal to or above the metabolomic threshold. The metabolomic changes at AHI levels defining moderate and severe OSA were smaller than at an AHI of 5 events·h-1. Conclusions: The metabolomic threshold for patients with sleep complaints described in this report for the first time coincides with the AHI threshold required to confirm the diagnosis of OSA.

Changes in Lipoprotein Particles in the Blood Serum of Patients with Lichen Planus.

Lichen planus is a chronic inflammatory mucocutaneous disease that belongs to the group of papulosquamous skin diseases among diseases like psoriasis, a widely studied disease in dermatology. The aim of the study was to identify the changes between the blood sera of lichen planus patients and healthy controls to widen the knowledge about the metabolomic aspect of lichen planus and gain a better understanding about the pathophysiology of the disease. We used high-throughput nuclear magnetic resonance (NMR) spectroscopy to measure the levels of blood serum metabolites, lipoproteins and lipoprotein particles. Dyslipidemia has relatively recently been shown to be one of the comorbidities of lichen planus, but the changes in the components of lipoproteins have not been described yet. We found statistically significant changes in the concentrations of 16 markers regarding lipoproteins, which included the components of intermediate-density lipoproteins, low-density lipoproteins and large low-density lipoproteins. We propose that the detected changes may increase the risk for specific comorbidities (e.g., dyslipidemia) and resulting cardiovascular diseases, as the turnover and hepatic uptake of the altered/modified lipoprotein particles are disturbed.

Metabolomic Differences between the Skin and Blood Sera of Atopic Dermatitis and Psoriasis.

Atopic dermatitis (AD) and psoriasis (PS) are common chronic inflammatory dermatoses. Although the differences at the intercellular and intracellular signaling level between AD and PS are well described, the resulting differences at the metabolism level have not yet been systematically analyzed. We compared the metabolomic profiles of the lesional skin, non-lesional skin and blood sera of AD and PS. Skin biopsies from 15 patients with AD, 20 patients with PS and 17 controls were collected, and 25 patients with AD, 55 patients with PS and 63 controls were recruited for the blood serum analysis. Serum and skin samples were analyzed using a targeted approach to find the concentrations of 188 metabolites and their ratios. A total of 19 metabolites differed in the comparison of lesional skins, one metabolite in non-lesional skins and 5 metabolites in blood sera. Although we found several metabolomic similarities between PS and AD, clear differences were outlined. Sphingomyelins were elevated in lesional skin of AD, implying a deficient barrier function. Increased levels of phosphatidylcholines, carnitines and asymmetric dimethylarginine in PS lesional skin and carnitines amino acids in the PS serum pointed to elevated cell proliferation. The comparison of the metabolomic profiles of AD and PS skin and sera outlined distinct patterns that were well correlated with the differences in the pathogenetic mechanisms of these two chronic inflammatory dermatoses.

Seroprevalence and levels of IgG antibodies after COVID-19 infection or vaccination.

BACKGROUND: In a country-wide seroprevalence study of COVID-19 in Estonia, we aimed to determine the seroprevalence and the dynamics of IgG against SARS-CoV-2 after vaccination or positive PCR-test. METHODS: Leftover blood samples were selected between 8 February and 25 March 2021, by SYNLAB Estonia from all counties and age groups (0-9, 10-19, 20-59, 60-69, 70-79 and 80-100 years) proportionally to the whole Estonian population and tested for IgG against SARS-CoV-2 spike protein receptor-binding domain (anti-S-RBD IgG) using Abbott SARS-CoV-2 IgG II Quant assay. Antibody levels after positive PCR-test or vaccination were described by exponential increase-decrease models. RESULTS: According to total of 2517 samples, overall seroprevalence (95% confidence interval [CI]) was 20.1% (18.5-21.7%), similar in all age groups, but varied between counties. If individuals vaccinated with the first dose at least 14 d before antibody measurement were assumed to be seronegative, the overall seroprevalence was 15.8% (14.4-17.3%), 4.0-fold larger than the proportion of PCR-confirmed COVID-19 cases. Of seropositive individuals (n = 506) 194 (38.3%; 33.8-43.1%) had not had positive PCR-test or been vaccinated. According to exponential increase-decrease model, the peak of anti-S-RBD IgG in a 52-year-old (median age of PCR-positive and/or vaccinated individuals) was significantly higher after vaccination compared with positive PCR-test (22,082 (12,897-26,875) vs. 6732 (2321-8243) AU/mL), but half-life was similar (26.5 (6.9-46.1) vs. 38.3 (8.2-68.5) d). CONCLUSIONS: One year after the start of COVID-19 pandemic the actual prevalence of infection is still underestimated compared with PCR-confirmed COVID-19 cases. Older compared with younger individuals have lower anti-S-RBD IgG level after vaccination, but similar decline rate.

Metabolomic Profile of Abdominal Aortic Aneurysm.

Abdominal aortic aneurysm (AAA) is characterized by structural deterioration of the aortic wall, leading to aortic dilation and rupture. The aim was to compare 183 low molecular weight metabolites in AAA patients and aorta-healthy controls and to explore if low molecular weight metabolites are linked to AAA growth. Blood samples were collected from male AAA patients with fast (mean 3.3 mm/year; range 1.3-9.4 mm/year; n = 39) and slow growth (0.2 mm/year; range -2.6-1.1 mm/year; n = 40), and from controls with non-aneurysmal aortas (n = 79). Targeted analysis of 183 metabolites in plasma was performed with AbsoluteIDQ p180 kit. The samples were measured on a QTRAP 4500 coupled to an Agilent 1260 series HPLC. The levels of only four amino acids (histidine, asparagine, leucine, isoleucine) and four phosphatidylcholines (PC.ae.C34.3, PC.aa.C34.2, PC.ae.C38.0, lysoPC.a.C18.2) were found to be significantly lower (p < 0.05) after adjustment for confounders among the AAA patients compared with the controls. There were no differences in the metabolites distinguishing the AAA patients with slow or fast growth from the controls, or distinguishing the patients with slow growth from those with fast growth. The current study describes novel significant alterations in amino acids and phosphatidylcholines metabolism associated with AAA occurrence, but no associations were found with AAA growth rate.

The effect of obstructive sleep apnea on peripheral blood amino acid and biogenic amine metabolome at multiple time points overnight.

There are no clinical studies that have investigated the differences in blood serum metabolome between obstructive sleep apnea (OSA) patients and controls. In a single-center prospective observational study, we compared metabolomic profiles in the serum of OSA patients with apnea-hypopnea index (AHI) ≥ 15/h and control individuals. Peripheral blood was obtained at 3 different time points overnight: 9:00 p.m.; 5:00 a.m. and 7:00 a.m. We used a targeted approach for detecting amino acids and biogenic amines and analyzed the data with ranked general linear model for repeated measures. We recruited 31 patients with moderate-to-severe OSA and 32 controls. Significant elevations in median concentrations of alanine, proline and kynurenine in OSA patients compared to controls were detected. Significant changes in the overnight dynamics of serum concentrations occurred in OSA: glutamine, serine, threonine, tryptophan, kynurenine and glycine levels increased, whereas a fall occurred in the same biomarker levels in controls. Phenylalanine and proline levels decreased slightly, compared to a steeper fall in controls. The study indicates that serum profiles of amino acid and biogenic amines are significantly altered in patients with OSA referring to vast pathophysiologic shifts reflected in the systemic metabolism.

Metabolomic Analysis of Skin Biopsies from Patients with Atopic Dermatitis Reveals Hallmarks of Inflammation, Disrupted Barrier Function and Oxidative Stress.

The main objectives of this study were to characterize the metabolomic profile of lesional skin of patients with atopic dermatitis, and to compare it with non- lesional skin of patients with atopic dermatitis and skin of controls with no dermatological disease. Skin-punch biopsies were collected from 15 patients and 17 controls. Targeted analysis of 188 metabolites was conducted. A total of 77 metabolites and their ratios were found, which differed significantly between lesional skin of atopic dermatitis, non-lesional skin of atopic dermatitis and skin of controls. The metabolites were members of the following classes: amino acids, biogenic amines, acylcarnitines, sphingomyelins or phosphatidylcholines, and the most significant differences be-tween the groups compared were in the concentrations of putrescine, SM.C26.0 and SM.C26.1. The alterations in metabolite levels indicate inflammation, impaired barrier function, and susceptibility to oxidative stress in atopic skin.

Hyperproliferation is the main driver of metabolomic changes in psoriasis lesional skin.

Systematic understanding of the metabolite signature of diseases may lead to a closer understanding of the disease pathogenesis and ultimately to the development of novel therapies and diagnostic tools. Here we compared for the first time the full metabolomic profiles of lesional and non-lesional skin biopsies obtained from plaque psoriasis patients and skin samples of healthy controls. Significant differences in the concentration levels of 29 metabolites were identified that provide several novel insights into the metabolic pathways of psoriatic lesions. The metabolomic profile of the lesional psoriatic skin is mainly characterized by hallmarks of increased cell proliferation. As no significant differences were identified between non-lesional skin and healthy controls we conclude that local inflammatory process that drives the increased cell proliferation is the main cause of the identified metabolomic shifts.

Repeated Administration of D-Amphetamine Induces Distinct Alterations in Behavior and Metabolite Levels in 129Sv and Bl6 Mouse Strains.

The main goal of the study was to characterize the behavioral and metabolomic profiles of repeated administration (for 11 days) of d-amphetamine (AMPH, 3 mg/kg i. p.), indirect agonist of dopamine (DA), in widely used 129S6/SvEvTac (129Sv) and C57BL/6NTac (Bl6) mouse strains. Acute administration of AMPH (acute AMPH) induced significantly stronger motor stimulation in Bl6. However, repeated administration of AMPH (repeated AMPH) caused stronger motor sensitization in 129Sv compared acute AMPH. Body weight of 129Sv was reduced after repeated saline and AMPH, whereas no change occurred in Bl6. In the metabolomic study, acute AMPH induced an elevation of isoleucine and leucine, branched chain amino acids (BCAA), whereas the level of hexoses was reduced in Bl6. Both BCAAs and hexoses remained on level of acute AMPH after repeated AMPH in Bl6. Three biogenic amines [asymmetric dimethylarginine (ADMA), alpha-aminoadipic acid (alpha-AAA), kynurenine] were significantly reduced after repeated AMPH. Acute AMPH caused in 129Sv a significant reduction of valine, lysophosphatidylcholines (lysoPC a C16:0, lysoPC a C18:2, lysoPC a C20:4), phosphatidylcholine (PC) diacyls (PC aa C34:2, PC aa C36:2, PC aa C36:3, PC aa C36:4) and alkyl-acyls (PC ae C38:4, PC ae C40:4). However, repeated AMPH increased the levels of valine and isoleucine, long-chain acylcarnitines (C14, C14:1-OH, C16, C18:1), PC diacyls (PC aa C38:4, PC aa C38:6, PC aa C42:6), PC acyl-alkyls (PC ae C38:4, PC ae C40:4, PC ae C40:5, PC ae C40:6, PC ae C42:1, PC ae C42:3) and sphingolipids [SM(OH)C22:1, SM C24:0] compared to acute AMPH in 129Sv. Hexoses and kynurenine were reduced after repeated AMPH compared to saline in 129Sv. The established changes probably reflect a shift in energy metabolism toward lipid molecules in 129Sv because of reduced level of hexoses. Pooled data from both strains showed that the elevation of isoleucine and leucine was a prominent biomarker of AMPH-induced behavioral sensitization. Simultaneously a significant decline of hexoses, citrulline, ADMA, and kynurenine occurred. The reduced levels of kynurenine, ADMA, and citrulline likely reflect altered function of N-methyl-D-aspartate (NMDA) and NO systems caused by repeated AMPH. Altogether, 129Sv strain displays stronger sensitization toward AMPH and larger variance in metabolite levels than Bl6.

Phenotyping of Chronic Obstructive Pulmonary Disease Based on the Integration of Metabolomes and Clinical Characteristics.

Apart from the refined management-oriented clinical stratification of chronic obstructive pulmonary disease (COPD), the molecular pathologies behind this highly prevalent disease have remained obscure. The aim of this study was the characterization of patients with COPD, based on the metabolomic profiling of peripheral blood and exhaled breath condensate (EBC) within the context of defined clinical and demographic variables. Mass-spectrometry-based targeted analysis of serum metabolites (mainly amino acids and lipid species), untargeted profiles of serum and EBC of patients with COPD of different clinical characteristics (n = 25) and control individuals (n = 21) were performed. From the combined clinical/demographic and metabolomics data, associations between clinical/demographic and metabolic parameters were searched and a de novo phenotyping for COPD was attempted. Adjoining the clinical parameters, sphingomyelins were the best to differentiate COPD patients from controls. Unsaturated fatty acid-containing lipids, ornithine metabolism and plasma protein composition-associated signals from the untargeted analysis differentiated the Global Initiative for COPD (GOLD) categories. Hierarchical clustering did not reveal a clinical-metabolomic stratification superior to the strata set by the GOLD consensus. We conclude that while metabolomics approaches are good for finding biomarkers and clarifying the mechanism of the disease, there are no distinct co-variate independent clinical-metabolic phenotypes.

Metabolic profile associated with distinct behavioral coping strategies of 129Sv and Bl6 mice in repeated motility test.

We investigated the metabolic outcome of different coping strategies in 129S6/SvEvTac (129Sv) and C57BL/6Ntac (Bl6) strains. Two different batches of male 129Sv and Bl6 mice were used. One batch was not subjected to any behavioral manipulations (home cage control; HCC), whereas the other batch was treated with saline for 11 days and exposed after every treatment to the motor activity measurement (repeated motility tested; RMT). Bl6 RMT mice displayed a robust increase in number of rearings during repeated testing. 129Sv RMT mice experienced significant loss of body weight, but showed enhanced weight gain in HCC batch compared to Bl6. Serum metabolites (acylcarnitines, amino acids, biogenic amines, hexoses, glycerophospholipids and sphingolipids) were determined with AbsoluteIDQ p180 kit. Results of the metabolomic study revealed prominent peculiarities between strains in two different conditions. Comparison of both batches of mice demonstrated that in Bl6 biogenic amines (acetyl-ornithine, alpha-amionadipic acid, carnosine) and lysophosphatidylcholine PC(16:1/0:0) dominated. However in 129Sv acylcarnitine C5 clearly dominated, indicating shift towards short-chain acylcarnitines. Stable strain-specific ratios also emerged for both lines, ratio of glycine/PC ae C38:2 for Bl6 and ratios of C5/C0 as well as PC(16:0/0:0)/PC(16:1/0:0) for 129Sv. The described metabolic changes probably reflect different behavioral coping strategies of 129Sv and Bl6 mice.

Medium- and long-chain acylcarnitines are associated with osteoarthritis severity and arterial stiffness in end-stage osteoarthritis patients: a case-control study.

AIM: Arterial pathology has been suggested to be involved in osteoarthritis (OA). Metabolic profiling enables the determination of low-molecular-weight molecules, which might further explain the pathogenesis of OA and its relationship with cardiovascular diseases (CVD). The aim of this study was to compare the metabolic profile of lipid metabolism-related compounds and arterial stiffness in OA patients and in controls. METHOD: The serum of 70 end-stage OA patients prior to joint replacement surgery and 82 age-matched controls were analyzed by the AbsoluteIDQ™ p180 kit (BIOCRATES Life Sciences AG, Innsbruck, Austria) using the targeted metabolomic approach. Arterial stiffness was assessed by measuring carotid-femoral and carotid-radial pulse wave velocity. Aortic-brachial pulse wave velocity ratio (PWV-ratio) was used as the measure of arterial stiffness gradient. Principal component analysis was performed to analyze the large number of metabolites. RESULTS: The OA patients had decreased levels of C10:1, C10:2, C12, C12:1, C14, C14:2, C14:1-OH, carnitine palmitoyltransferase 1 (CPT1) ratio and total AC/C0 compared with age-matched controls. There was independent association between acylcarnitines and PWV-ratio in the OA patients. Furthermore, acylcarnitines were associated with OA radiographic severity. The component that resembles acylcarnitines was an independent predictor of the PWV-ratio for OA patients. CONCLUSION: We found decreased levels of acylcarnitines in OA patients. Furthermore, medium-and long-chain acylcarnitines associated independently with arterial stiffness and were related to radiographic severity of OA. Thus, acylcarnities might play an important role in the association between OA and CVD.

Blood serum metabolome of atopic dermatitis: Altered energy cycle and the markers of systemic inflammation.

Atopic dermatitis is a chronic inflammatory disease which usually starts in the early childhood and ends before adulthood. However up to 3% of adults remain affected by the disease. The onset and course of the disease is influenced by various genetic and environmental factors. Although the immune system has a great effect on the outcome of the disease, metabolic markers can also try to explain the background of atopic dermatitis. In this study we analyzed the serum of patients with atopic dermatitis using both targeted and untargeted metabolomics approaches. We found the most significant changes to be related to phosphatidylcholines, acylcarnitines and their ratios and a cleavage peptide of Fibrinogen A-α. These findings that have not been reported before will further help to understand this complex disease.

Profiling of Acylcarnitines in First Episode Psychosis before and after Antipsychotic Treatment.

Acylcarnitines (ACs) have been shown to have a potential to activate pro-inflammatory signaling pathways and to foster the development of insulin resistance. The first task of the current study was to study the full list of ACs (from C2 to C18) in first episode psychosis (FEP) patients before and after antipsychotic treatment. The second task was to relate ACs to inflammatory and metabolic biomarkers established in the same patient cohort as in our previous studies. Serum levels of ACs were determined with the AbsoluteIDQ p180 kit (BIOCRATES Life Sciences AG, Innsbruck, Austria) using the flow injection analysis tandem mass spectrometry ([FIA]-MS/MS) as well as liquid chromatography ([LC]-MS/MS) technique. Identification and quantification of the metabolites was achieved using multiple reactions monitoring along with internal standards. The comparison of ACs in antipsychotic-naïve first-episode psychosis (FEP) patients (N = 38) and control subjects (CSs, N = 37) revealed significantly increased levels of long-chain ACs (LCACs) C14:1 (p = 0.0001), C16 (p = 0.00002), and C18:1 (p = 0.000001) in the patient group. These changes of LCACs were associated with augmented levels of CARN palmitoyltransferase 1 (CPT-1) (p = 0.006). By contrast, the level of short-chain AC (SCAC) C3 was significantly reduced (p = 0.00003) in FEP patients. Seven months of antipsychotic drug treatment ameliorated clinical symptoms in patients (N = 36) but increased significantly their body mass index (BMI, p = 0.001). These changes were accompanied by significantly reduced levels of C18:1 (p = 0.00003) and C18:2 (p = 0.0008) as well as increased level of C3 (p = 0.01). General linear model revealed the relation of LCACs (C16, C16:1, and C18:1) to the inflammatory markers (epidermal growth factor, IL-2, IL-4, IL-6), whereas SCAC C3 was linked to the metabolic markers (leptin, C-peptide) and BMI. FEP was associated with an imbalance of ACs in patients because the levels of several LCACs were significantly higher and the levels of several SCACs were significantly reduced compared with CSs. This imbalance was modified by 7 months of antipsychotic drug treatment, reversing the levels of both LCACs and SCACs to that established for CSs. This study supports the view that ACs have an impact on both inflammatory and metabolic alterations inherent for FEP.

The metabolic analysis of psoriasis identifies the associated metabolites while providing computational models for the monitoring of the disease.

The majority of studies on psoriasis have focused on explaining the genetic background and its associations with the immune system's response. The aim of this study was to identify the low-molecular weight compounds contributing to the metabolomic profile of psoriasis and to provide computational models that help with the classification and monitoring of the severity of the disease. We compared the results from targeted and untargeted analyses of patients' serums with plaque psoriasis to controls. The main differences were found in the concentrations of acylcarnitines, phosphatidylcholines, amino acids, urea, phytol, and 1,11-undecanedicarboxylic acid. The data from the targeted analysis were used to build classification models for psoriasis. The results from this study provide an overview of the metabolomic serum profile of psoriasis along with promising statistical models for the monitoring of the disease.

Taurine and Epidermal Growth Factor Belong to the Signature of First-Episode Psychosis.

This study evaluated the levels of two amino acid derivatives taurine and spermine in first-episode psychosis (FEP) patients and their response to antipsychotic treatment. The levels of taurine and spermine were significantly up-regulated in antipsychotic-naïve FEP patients compared to control subjects (CS). Treatment of FEP patients with antipsychotic drugs significantly reduced the positive symptoms of schizophrenia. This positive effect was accompanied by a significant reduction of taurine and spermine to the levels measured in CS. General linear model was used to establish associations of taurine and spermine with the levels of cytokines and growth factors, measured in our previous experiments using the same study sample. There was a strong association between taurine and epidermal growth factor (EGF). Both biomarkers significantly correlated with the disease symptoms as well as with the effectiveness of antipsychotic treatment. Accordingly one can conclude that taurine and EGF belong to the signature of FEP. Most probably they reflect altered oxidative stress and corrupted function of N-methyl-D-aspartate (NMDA) receptors in FEP.