Metabolome-wide association study on ABCA7 indicates a role of ceramide metabolism in Alzheimer's disease.

Genome-wide association studies (GWASs) have identified genetic loci associated with the risk of Alzheimer's disease (AD), but the molecular mechanisms by which they confer risk are largely unknown. We conducted a metabolome-wide association study (MWAS) of AD-associated loci from GWASs using untargeted metabolic profiling (metabolomics) by ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). We identified an association of lactosylceramides (LacCer) with AD-related single-nucleotide polymorphisms (SNPs) in ABCA7 (P = 5.0 × 10-5 to 1.3 × 10-44). We showed that plasma LacCer concentrations are associated with cognitive performance and genetically modified levels of LacCer are associated with AD risk. We then showed that concentrations of sphingomyelins, ceramides, and hexosylceramides were altered in brain tissue from Abca7 knockout mice, compared with wild type (WT) (P = 0.049-1.4 × 10-5), but not in a mouse model of amyloidosis. Furthermore, activation of microglia increases intracellular concentrations of hexosylceramides in part through induction in the expression of sphingosine kinase, an enzyme with a high control coefficient for sphingolipid and ceramide synthesis. Our work suggests that the risk for AD arising from functional variations in ABCA7 is mediated at least in part through ceramides. Modulation of their metabolism or downstream signaling may offer new therapeutic opportunities for AD.

Infra-areolar subcutaneous mastectomy in the surgical treatment of adolescent gynecomastia.

BACKGROUND: Despite being a common condition in puberty, only 5-10% of pubertal gynecomastia need surgical treatment. Here the authors present their experiences with infra-areolar subcutaneous mastectomy in the surgical treatment of adolescent gynecomastia. METHODS: The records of patients who underwent infra-areolar subcutaneous mastectomy for adolescent gynecomastia between January 2004 and December 2021 were reviewed retrospectively. The patients' demographic data, complaints and clinical presentation, physical examination, laboratory and radiological findings, surgical management, and postoperative follow-ups were evaluated. The patients were evaluated according to the localization of the gynecomastia (unilateral/bilateral) and according to the patients' body mass index (BMI) (normal/overweight). RESULTS: A total of 21 boys with a mean age of 15 ± 1.4 years were operated by the senior author and infra-areolar subcutaneous mastectomy by a semilunar incision was performed for adolescent gynecomastia. The mean duration of the complaint was 24.2 ± 10.9 months. Gynecomastia was bilateral in 15 (71.5%) and unilateral in 6 (28.5%) of the patients. Sixteen patients (76.2%) were normal weight, 5 (23.8%) were overweight. Chromosomal anomaly and hypogonadism were detected in two patients. Pseudoangiomatous stromal hyperplasia was detected in the pathology of one patient. The mean follow-up time was 2.7 ± 1 years, seroma developed in 2 patients at the early postoperative period. Their long-term follow-up was uneventful without complication. CONCLUSIONS: The results of infra-areolar subcutaneous mastectomy are very promising in pubertal gynecomastia due to good skin elasticity and without obesity in the adolescent age group. We believe that this method provides an almost invisible incision and a natural pectoral appearance for adolescent patients who have experienced serious emotional problems related to their body images.

Pathway-based integration of multi-omics data reveals lipidomics alterations validated in an Alzheimer's disease mouse model and risk loci carriers.

Alzheimer's disease (AD) is a highly prevalent neurodegenerative disorder. Despite increasing evidence of the importance of metabolic dysregulation in AD, the underlying metabolic changes that may impact amyloid plaque formation are not understood, particularly for late-onset AD. This study analyzed genome-wide association studies (GWAS), transcriptomics, and proteomics data obtained from several data repositories to obtain differentially expressed (DE) multi-omics elements in mouse models of AD. We characterized the metabolic modulation in these data sets using gene ontology, transcription factor, pathway, and cell-type enrichment analyses. A predicted lipid signature was extracted from genome-scale metabolic networks (GSMN) and subsequently validated in a lipidomic data set derived from cortical tissue of ABCA-7 null mice, a mouse model of one of the genes associated with late-onset AD. Moreover, a metabolome-wide association study (MWAS) was performed to further characterize the association between dysregulated lipid metabolism in human blood serum and genes associated with AD risk. We found 203 DE transcripts, 164 DE proteins, and 58 DE GWAS-derived mouse orthologs associated with significantly enriched metabolic biological processes. Lipid and bioenergetic metabolic pathways were significantly over-represented across the AD multi-omics data sets. Microglia and astrocytes were significantly enriched in the lipid-predominant AD-metabolic transcriptome. We also extracted a predicted lipid signature that was validated and robustly modeled class separation in the ABCA7 mice cortical lipidome, with 11 of these lipid species exhibiting statistically significant modulations. MWAS revealed 298 AD single nucleotide polymorphisms-metabolite associations, of which 70% corresponded to lipid classes. These results support the importance of lipid metabolism dysregulation in AD and highlight the suitability of mapping AD multi-omics data into GSMNs to identify metabolic alterations.

Metabolomic Profile of the Healthy Eating Index-2015 in the Multiethnic Study of Atherosclerosis.

BACKGROUND: Poor diet quality is a risk factor for type 2 diabetes and cardiovascular disease. However, knowledge of metabolites marking adherence to Dietary Guidelines for Americans (2015 version) are limited. OBJECTIVES: The goal was to determine a pattern of metabolites associated with the Healthy Eating Index (HEI)-2015, which measures adherence to the Dietary Guidelines for Americans. METHODS: The analysis examined 3557 adult men and women from the longitudinal cohort Multiethnic Study of Atherosclerosis (MESA), without known cardiovascular disease and with complete dietary data. Fasting serum specimens and diet and demographic questionnaires were assessed at baseline. Untargeted 1H 1-dimensional nuclei magnetic resonance spectroscopy (600 MHz) was used to generate metabolomics and lipidomics. A metabolome-wide association study specified each spectral feature as outcomes, HEI-2015 score as predictor, adjusting for age, sex, race, and study site in linear regression analyses. Subsequently, hierarchical clustering defined the discrete groups of correlated nuclei magnetic resonance features associated with named metabolites, and the linear regression analysis assessed for associations with HEI-2015 total and component scores. RESULTS: The sample included 50% women with an mean age of 63 years, with 40% identifying as White, 23% as Black, 24% as Hispanic, and 13% as Chinese American. The mean HEI-2015 score was 66. The metabolome-wide association study identified 179 spectral features significantly associated with HEI-2015 score. The cluster analysis identified 7 clusters representing 4 metabolites; HEI-2015 score was significantly associated with all. HEI-2015 score was associated with proline betaine [ß = 0.12 (SE = 0.02); P = 4.70 × 10-13] and was inversely related to proline [ß = -0.13 (SE = 0.02); P = 4.45 × 10-14], 1,5 anhydrosorbitol [ß = -0.08 (SE = 0.02); P = 4.37 × 10-7] and unsaturated fatty acyl chains [ß = 0.08 (SE = 0.02); P = 8.98 × 10-7]. Intake of total fruit, whole grains, and seafood and plant proteins was associated with proline betaine. CONCLUSIONS: Diet quality is significantly associated with unsaturated fatty acyl chains, proline betaine, and proline. Further analysis may clarify the link between diet quality, metabolites, and pathogenesis of cardiometabolic disease.

Finding Correspondence between Metabolomic Features in Untargeted Liquid Chromatography-Mass Spectrometry Metabolomics Datasets.

Integration of multiple datasets can greatly enhance bioanalytical studies, for example, by increasing power to discover and validate biomarkers. In liquid chromatography-mass spectrometry (LC-MS) metabolomics, it is especially hard to combine untargeted datasets since the majority of metabolomic features are not annotated and thus cannot be matched by chemical identity. Typically, the information available for each feature is retention time (RT), mass-to-charge ratio (m/z), and feature intensity (FI). Pairs of features from the same metabolite in separate datasets can exhibit small but significant differences, making matching very challenging. Current methods to address this issue are too simple or rely on assumptions that cannot be met in all cases. We present a method to find feature correspondence between two similar LC-MS metabolomics experiments or batches using only the features' RT, m/z, and FI. We demonstrate the method on both real and synthetic datasets, using six orthogonal validation strategies to gauge the matching quality. In our main example, 4953 features were uniquely matched, of which 585 (96.8%) of 604 manually annotated features were correct. In a second example, 2324 features could be uniquely matched, with 79 (90.8%) out of 87 annotated features correctly matched. Most of the missed annotated matches are between features that behave very differently from modeled inter-dataset shifts of RT, MZ, and FI. In a third example with simulated data with 4755 features per dataset, 99.6% of the matches were correct. Finally, the results of matching three other dataset pairs using our method are compared with a published alternative method, metabCombiner, showing the advantages of our approach. The method can be applied using M2S (Match 2 Sets), a free, open-source MATLAB toolbox, available at https://github.com/rjdossan/M2S.

The effect of pulsed radiofrequency application on nerve healing after sciatic nerve anastomosis in rats.

The Effect of Pulsed Radiofrequency Application on Nerve Healing After Sciatic Nerve Anastomosis in Rats. In this study, we aimed to evaluate the histomorphological and functional effect of Pulsed Radiofrequency (PRF) application on regeneration after experimental nerve damage in rats. Forty Sprague-Dawley male rats were used in the study. Sciatic nerve incision was applied to all rats and then anastomosis was performed. Twenty rats were separated as the control group, and the remaining 20 rats underwent PRF every day at 42oC, for 120 seconds. The groups were divided into two further subgroups to be sacrificed on the 15th and 30th days. Tissue samples were obtained from all groups at 24 hours and 72 hours after the injury. Sections of sciatic nerve samples were stained with hematoxylin-eosin for light microscopic investigation and prepared for evaluation of ultrastructural changes with transmission electron microscopy. In the evaluation of axon numbers and diameters were seen that the 30th-day RF group had an increase compared to the control group. In the electron microscopic examination, it was observed that myelinated and unmyelinated nerve fiber sheaths had borders that are more regular in the RF group, the nucleus structures of schwann cells were better preserved, mitochondrial damage was less, and the extensions of fibroblast and collagen fibers were smoother than the control group. The findings suggested that PRF application has a positive contribution histologically on nerve healing in the early period after full-layer incision nerve injury anastomosis surgery.

COVID-19 pandemic and lockdown: what has changed in common home accidents such as foreign bodies and corrosive injuries?

BACKGROUND: COVID-19 pandemic greatly affected our lives in all areas. Due to the social isolation policies implemented during this period, the majority of parents and all school-age children spent their lives at home. This study aims to investigate the effects of pandemic and isolation on home accidents treated in our center. METHODS: Foreign body ingestion (gastric foreign bodies: G.FB), foreign body aspiration (respiratory foreign bodies: R.FB), and corrosive substance (CS) ingestion cases admitted to our hospital between March 11, 2019, and March 10, 2021, were retrospectively analyzed. Demographic data, type and cause of home accidents, the time of the accident and the admission to the hospital, the location of the foreign body, and the follow-up data were recorded. The patients were divided into two groups: the pre-pandemic period (11 March 2019-10 March 2020) and the COVID pandemic period (11 March 2020-10 March 2021), and the data were evaluated between two groups as < 6 years old and 6-18 years old. RESULTS: During the 2 years, a total of 982 patients were admitted to our hospital for G.FB, R.FB, or CS. Four hundred and eighty-three of them (49.2%) were in the pre-pandemic period and 499 (50.8%) were in the pandemic period (p = 0.206). The mean age of the patients was 3.63 ± 3.32 years; 82.4% of the patients in the pre-pandemic group and 85.4% of the patients in the pandemic group were children < 6 years old. While the F/M ratio was 1/1.5 during the pre-pandemic period, it was 1/1.1 during the pandemic period. Of the cases, 73.3% were G.FB, 4.6% were R.FB, and 22.1% were CS. Almost half of the accidents occurred between the hours of 16 and 24. During the pandemic period, the accidents increased to occur between 0 and 8 am in children < 6 years old, and between 8 am and 4 pm in children 6-18 years old (p = 0.003). All of the home accidents in the 6-18 age group between 0 and 8 o'clock were girls (p < 0.0001). During the pandemic period, the frequency of button batteries and food products increased in G.FB. Also, the frequency of R.FB increased significantly (p = 0.006) and the most common R.FB was the food products. The frequency of CS increased in girls during the pandemic period, and CSs were brought to the hospital in a shorter time after the accident during the pandemic period (p = 0.007). CONCLUSIONS: It can be thought that the main reason why home accidents are common in the 0-6 age group is due to the developmental characteristics of the child rather than the longer time spent at home. The pandemic and isolation increase the frequency of foreign body aspirations and home accidents in girls.

The effects of hesperidin on stricture formation in corrosive esophageal burns: an experimental study.

AIM/BACKGROUND: Esophageal strictures in children that develop as a result of accidental ingestion of corrosive substances remain an important health problem. The purpose of this study is to determine the effects of Hesperidin, an effective bioflavonoid in the proliferative and exudative phase of inflammation, on the stricture formation in corrosive esophageal burns. METHODS: Experimental esophageal burns in rats were created using a modified Gehanno and Guedon model with 20% NaOH. Rats were divided into 5 groups. In the Sham group, the distal esophagus was prepared and cannulated according to the model, but no NaOH was administrated. The esophageal burn was created with NaOH in the other groups. The burned groups were divided into two groups as untreated (T14, T21) and treated with 100 mg/kg/day Hesperidin (H14, H21) intraperitoneally, and these groups were divided into two according to their sacrification periods (14 and 21 days). Inflammation, fibrosis, and necrosis were graded by histopathological evaluation in all groups. The efficacy of treatment was evaluated using the weight of rats, stenosis index, and histopathological parameters. RESULTS: Histopathologic damage scores such as inflammation, necrosis, and fibrosis were lower in the H14 and H21 groups and higher in the T14 and T21 groups. And also stenosis index was found higher in T14 and T21 groups (p < 0.05), while it was similar to the Sham group in H14 and H21 groups. No statistically significant difference was found between the H14 and H21 groups in terms of stenosis index. When weights of the rats at the beginning and end of the experiment were compared, weights of the H14 and H21 groups and the Sham group were similar. There was a significant decrease in the weight of the rats in the T14 and T21 groups (p < 0.001). CONCLUSIONS: This study is the first to use Hesperidin in preventing esophageal damage in an esophageal caustic burn model. It was shown that Hesperidin was effective in reducing macroscopic and microscopic histopathologic damage in the corrosive esophageal burn model, preventing the stricture formation, and has positive effects on nutrition in rats with an esophageal burn.

Higher thyrotropin leads to unfavorable lipid profile and somewhat higher cardiovascular disease risk: evidence from multi-cohort Mendelian randomization and metabolomic profiling.

BACKGROUND: Observational studies suggest interconnections between thyroid status, metabolism, and risk of coronary artery disease (CAD), but causality remains to be proven. The present study aimed to investigate the potential causal relationship between thyroid status and cardiovascular disease and to characterize the metabolomic profile associated with thyroid status. METHODS: Multi-cohort two-sample Mendelian randomization (MR) was performed utilizing genome-wide significant variants as instruments for standardized thyrotropin (TSH) and free thyroxine (fT4) within the reference range. Associations between TSH and fT4 and metabolic profile were investigated in a two-stage manner: associations between TSH and fT4 and the full panel of 161 metabolomic markers were first assessed hypothesis-free, then directional consistency was assessed through Mendelian randomization, another metabolic profile platform, and in individuals with biochemically defined thyroid dysfunction. RESULTS: Circulating TSH was associated with 52/161 metabolomic markers, and fT4 levels were associated with 21/161 metabolomic markers among 9432 euthyroid individuals (median age varied from 23.0 to 75.4 years, 54.5% women). Positive associations between circulating TSH levels and concentrations of very low-density lipoprotein subclasses and components, triglycerides, and triglyceride content of lipoproteins were directionally consistent across the multivariable regression, MR, metabolomic platforms, and for individuals with hypo- and hyperthyroidism. Associations with fT4 levels inversely reflected those observed with TSH. Among 91,810 CAD cases and 656,091 controls of European ancestry, per 1-SD increase of genetically determined TSH concentration risk of CAD increased slightly, but not significantly, with an OR of 1.03 (95% CI 0.99-1.07; p value 0.16), whereas higher genetically determined fT4 levels were not associated with CAD risk (OR 1.00 per SD increase of fT4; 95% CI 0.96-1.04; p value 0.59). CONCLUSIONS: Lower thyroid status leads to an unfavorable lipid profile and a somewhat increased cardiovascular disease risk.

Targeted realignment of LC-MS profiles by neighbor-wise compound-specific graphical time warping with misalignment detection.

MOTIVATION: Liquid chromatography-mass spectrometry (LC-MS) is a standard method for proteomics and metabolomics analysis of biological samples. Unfortunately, it suffers from various changes in the retention times (RT) of the same compound in different samples, and these must be subsequently corrected (aligned) during data processing. Classic alignment methods such as in the popular XCMS package often assume a single time-warping function for each sample. Thus, the potentially varying RT drift for compounds with different masses in a sample is neglected in these methods. Moreover, the systematic change in RT drift across run order is often not considered by alignment algorithms. Therefore, these methods cannot effectively correct all misalignments. For a large-scale experiment involving many samples, the existence of misalignment becomes inevitable and concerning. RESULTS: Here, we describe an integrated reference-free profile alignment method, neighbor-wise compound-specific Graphical Time Warping (ncGTW), that can detect misaligned features and align profiles by leveraging expected RT drift structures and compound-specific warping functions. Specifically, ncGTW uses individualized warping functions for different compounds and assigns constraint edges on warping functions of neighboring samples. Validated with both realistic synthetic data and internal quality control samples, ncGTW applied to two large-scale metabolomics LC-MS datasets identifies many misaligned features and successfully realigns them. These features would otherwise be discarded or uncorrected using existing methods. The ncGTW software tool is developed currently as a plug-in to detect and realign misaligned features present in standard XCMS output. AVAILABILITY AND IMPLEMENTATION: An R package of ncGTW is freely available at Bioconductor and https://github.com/ChiungTingWu/ncGTW. A detailed user's manual and a vignette are provided within the package. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Relationship between Serum YKL-40 Level and Forearm Arterial Patency after Repair.

BACKGROUND: The study aimed to assess the effects of serum YKL-40 level on patency at the repair site in patients who underwent arterial repair at the level of the forearm. METHODS: The study included 58 subjects, including 29 patients (aged 18-50 years) who had ulnar or radial artery injury secondary to cut injury to wrist between June 2015 and November 2019 and no comorbid disease and 29 age- and sex-matched healthy controls. The vascular patency was assessed using Doppler sonography in patients who underwent arterial repair at the level of the forearm. The patients were defined as flow failure if the blood flow was ≤50%, and sufficient flow if the blood flow was >50% of those in the synonymous artery on the intact extremity. The YKL-40 level differences in the patient and control groups were compared to those in the sufficient and insufficient flow groups. RESULTS: The patients were stratified into 2 groups based on the presence of sufficient flow. The mean YKL level was 11.96 ± 8.87 in the sufficient flow groups, whereas it was 32.22 ± 15.43 in the insufficient flow groups (p= 0.038). Besides, it was found that each unit of increase in the YKL-40 level increased the likelihood of having flow failure by 1.128. CONCLUSION: Based on our results, it was observed that over-expression of the YKL-40 level has adverse effects on patency following arterial repair.

Serum metabolic signatures of coronary and carotid atherosclerosis and subsequent cardiovascular disease.

AIMS: To characterize serum metabolic signatures associated with atherosclerosis in the coronary or carotid arteries and subsequently their association with incident cardiovascular disease (CVD). METHODS AND RESULTS: We used untargeted one-dimensional (1D) serum metabolic profiling by proton nuclear magnetic resonance spectroscopy (1H NMR) among 3867 participants from the Multi-Ethnic Study of Atherosclerosis (MESA), with replication among 3569 participants from the Rotterdam and LOLIPOP studies. Atherosclerosis was assessed by coronary artery calcium (CAC) and carotid intima-media thickness (IMT). We used multivariable linear regression to evaluate associations between NMR features and atherosclerosis accounting for multiplicity of comparisons. We then examined associations between metabolites associated with atherosclerosis and incident CVD available in MESA and Rotterdam and explored molecular networks through bioinformatics analyses. Overall, 30 1H NMR measured metabolites were associated with CAC and/or IMT, P = 1.3 × 10-14 to 1.0 × 10-6 (discovery) and P = 5.6 × 10-10 to 1.1 × 10-2 (replication). These associations were substantially attenuated after adjustment for conventional cardiovascular risk factors. Metabolites associated with atherosclerosis revealed disturbances in lipid and carbohydrate metabolism, branched chain, and aromatic amino acid metabolism, as well as oxidative stress and inflammatory pathways. Analyses of incident CVD events showed inverse associations with creatine, creatinine, and phenylalanine, and direct associations with mannose, acetaminophen-glucuronide, and lactate as well as apolipoprotein B (P < 0.05). CONCLUSION: Metabolites associated with atherosclerosis were largely consistent between the two vascular beds (coronary and carotid arteries) and predominantly tag pathways that overlap with the known cardiovascular risk factors. We present an integrated systems network that highlights a series of inter-connected pathways underlying atherosclerosis.

Management of perinatal testicular torsion: experience of two tertiary centers.

PURPOSE: Perinatal testicular torsion is a rare condition in which testicular salvage rates are significantly low and management is controversial. We retrospectively evaluated our patients and aimed to go through our management approach. METHODS: The newborn patients who underwent surgery for testicular torsion in two tertiary referral centers between 2000 and 2019 are enrolled. Radiological and clinical findings are retrospectively evaluated. RESULTS: Thirty-two newborns are enrolled in the study. All of the cases were unilateral and 30 ended up with immediate orchidectomy while 2 received orchidopexy but both underwent atrophy on follow-up. No bilateral torsion is demonstrated neither in 16 patients with bilateral exploration nor in the follow up of the rest 16 with unilateral exploration. Intravaginal torsion was encountered in five patients (16%). No morbidity or mortality related to anesthesia is documented. No malignancy is encountered in any of the patients. CONCLUSION: Although ipsilateral testicular salvage rates are low, urgent bilateral exploration in a multidisciplinary center seems reasonable to give a chance to the ipsilateral testis and to avoid the rare but catastrophic bilateral torsion, after discussing with the family.

A comparison of human serum and plasma metabolites using untargeted 1H NMR spectroscopy and UPLC-MS.

INTRODUCTION: Differences in the metabolite profiles between serum and plasma are incompletely understood. OBJECTIVES: To evaluate metabolic profile differences between serum and plasma and among plasma sample subtypes. METHODS: We analyzed serum, platelet rich plasma (PRP), platelet poor plasma (PPP), and platelet free plasma (PFP), collected from 8 non-fasting apparently healthy women, using untargeted standard 1D and CPMG 1H NMR and reverse phase and hydrophilic (HILIC) UPLC-MS. Differences between metabolic profiles were evaluated using validated principal component and orthogonal partial least squares discriminant analysis. RESULTS: Explorative analysis showed the main source of variation among samples was due to inter-individual differences with no grouping by sample type. After correcting for inter-individual differences, lipoproteins, lipids in VLDL/LDL, lactate, glutamine, and glucose were found to discriminate serum from plasma in NMR analyses. In UPLC-MS analyses, lysophosphatidylethanolamine (lysoPE)(18:0) and lysophosphatidic acid(20:0) were higher in serum, and phosphatidylcholines (PC)(16:1/18:2, 20:3/18:0, O-20:0/22:4), lysoPC(16:0), PE(O-18:2/20:4), sphingomyelin(18:0/22:0), and linoleic acid were lower. In plasma subtype analyses, isoleucine, leucine, valine, phenylalanine, glutamate, and pyruvate were higher among PRP samples compared with PPP and PFP by NMR while lipids in VLDL/LDL, citrate, and glutamine were lower. By UPLC-MS, PE(18:0/18:2) and PC(P-16:0/20:4) were higher in PRP compared with PFP samples. CONCLUSIONS: Correction for inter-individual variation was required to detect metabolite differences between serum and plasma. Our results suggest the potential importance of inter-individual effects and sample type on the results from serum and plasma metabolic phenotyping studies.

Improving Visualization and Interpretation of Metabolome-Wide Association Studies: An Application in a Population-Based Cohort Using Untargeted 1H NMR Metabolic Profiling.

1H NMR spectroscopy of biofluids generates reproducible data allowing detection and quantification of small molecules in large population cohorts. Statistical models to analyze such data are now well-established, and the use of univariate metabolome wide association studies (MWAS) investigating the spectral features separately has emerged as a computationally efficient and interpretable alternative to multivariate models. The MWAS rely on the accurate estimation of a metabolome wide significance level (MWSL) to be applied to control the family wise error rate. Subsequent interpretation requires efficient visualization and formal feature annotation, which, in-turn, call for efficient prioritization of spectral variables of interest. Using human serum 1H NMR spectroscopic profiles from 3948 participants from the Multi-Ethnic Study of Atherosclerosis (MESA), we have performed a series of MWAS for serum levels of glucose. We first propose an extension of the conventional MWSL that yields stable estimates of the MWSL across the different model parameterizations and distributional features of the outcome. We propose both efficient visualization methods and a strategy based on subsampling and internal validation to prioritize the associations. Our work proposes and illustrates practical and scalable solutions to facilitate the implementation of the MWAS approach and improve interpretation in large cohort studies.

Preprocessing and Pretreatment of Metabolomics Data for Statistical Analysis.

From data acquisition to statistical analysis, metabolomics data need to undergo several processing steps, which are crucial for the data quality and interpretation of the results. In this chapter, methods for preprocessing, normalization, and pretreatment of metabolomics data generated from nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS) are presented and discussed. Preprocessing is reported for both NMR and MS analysis. The challenges in preprocessing such complex data are highlighted. Subsequently, normalization methods such as total area normalization, probabilistic quotient normalization, and quantile normalization are explained. Finally, several scaling and data transformation methods are discussed for metabolomics data pretreatment, which is an important step prior to statistical analysis.

Workflow for Integrated Processing of Multicohort Untargeted 1H NMR Metabolomics Data in Large-Scale Metabolic Epidemiology.

Large-scale metabolomics studies involving thousands of samples present multiple challenges in data analysis, particularly when an untargeted platform is used. Studies with multiple cohorts and analysis platforms exacerbate existing problems such as peak alignment and normalization. Therefore, there is a need for robust processing pipelines that can ensure reliable data for statistical analysis. The COMBI-BIO project incorporates serum from ∼8000 individuals, in three cohorts, profiled by six assays in two phases using both 1H NMR and UPLC-MS. Here we present the COMBI-BIO NMR analysis pipeline and demonstrate its fitness for purpose using representative quality control (QC) samples. NMR spectra were first aligned and normalized. After eliminating interfering signals, outliers identified using Hotelling's T2 were removed and a cohort/phase adjustment was applied, resulting in two NMR data sets (CPMG and NOESY). Alignment of the NMR data was shown to increase the correlation-based alignment quality measure from 0.319 to 0.391 for CPMG and from 0.536 to 0.586 for NOESY, showing that the improvement was present across both large and small peaks. End-to-end quality assessment of the pipeline was achieved using Hotelling's T2 distributions. For CPMG spectra, the interquartile range decreased from 1.425 in raw QC data to 0.679 in processed spectra, while the corresponding change for NOESY spectra was from 0.795 to 0.636, indicating an improvement in precision following processing. PCA indicated that gross phase and cohort differences were no longer present. These results illustrate that the pipeline produces robust and reproducible data, successfully addressing the methodological challenges of this large multifaceted study.

Medium-term outcomes of mosaicplasty versus arthroscopic microfracture with or without platelet-rich plasma in the treatment of osteochondral lesions of the talus.

PURPOSE: This study aimed to compare medium-term functional effects of three different treatment modalities in patients with osteochondral lesions of the talus (OLT). METHODS: Fifty-four patients undergoing arthroscopic surgery for osteochondral lesion of the talus were included in this study. Patients were assigned to one of the three treatment groups: microfracture surgery (n = 19), microfracture surgery plus platelet-rich plasma (PRP) (n = 22), and mosaicplasty (n = 13). Function was assessed using the American Orthopedic Foot and Ankle Society (AOFAS) scoring system and VAS scores for pain, before and after surgery. In addition, the Foot and Ankle Ability Measure (FAAM) tests for pain and 15-min walking were done at follow-up visits. RESULTS: The median duration of follow-up was 42 months (range 12-84 months). All groups showed significant improvements in AOFAS and VAS pain scores at the last follow-up visit, when compared to baseline. The groups did not differ with regard to change in baseline AOFAS score; however, improvement in VAS pain scores was significantly better in the mosaicplasty group when compared to the microfracture group (change from baseline, -5.8 ± 1.0 vs. -3.2 ± 2.9, p = 0.018). CONCLUSIONS: All the three treatment modalities resulted in good medium-term functional results. However, mosaicplasty procedure seems to be a promising option and it might be preferred particularly in patients where pain control is important. LEVEL OF EVIDENCE: II.

Whole Grain Consumption Increases Gastrointestinal Content of Sulfate-Conjugated Oxylipins in Pigs - A Multicompartmental Metabolomics Study.

The effects of increased intake of dietary fiber as either whole grain rye or as resistant starch compared to a typical low dietary fiber Western-style diet on the metabolomics responses were studied in gastrointestinal content and tissue, peripheral plasma, and urine using a multicompartmental nontargeted liquid chromatography-mass spectrometry (LC-MS) approach in pigs. Both unsupervised and supervised multivariate analyses were used to study differences between the intervention groups, revealing significant effects of the dietary intervention on gastrointestinal contents and urine metabolites. Consumption of a diet composed of whole grain rye flakes and enzyme treated wheat bran increased gastrointestinal content of novel sulfate- and acetic acid-conjugated oxylipins, and urinary secretion of phenolic compounds. Furthermore, potential gastrointestinal and urinary biomarkers for consumption of resistant starch, whole grain rye, and a low dietary fiber intake were detected using multiblock analysis. This study provides insight into microbial fermentation products in the gastrointestinal tract and suggests a potential role in sulfate conjugation of metabolites on the bioavailability of ingested nutrients.

Clinical outcomes of platelet rich plasma (PRP) as an adjunct to microfracture surgery in osteochondral lesions of the talus.

PURPOSE: To compare the effect of arthroscopic microfracture surgery alone or in combination with platelet rich plasma (PRP) on functional outcomes in osteochondral lesions of the talus. METHODS: A total of 35 patients were included in the study. Control subjects (n = 16) received treatment with microfracture surgery alone, while the remaining patients (PRP group, n = 19) were also given PRP. After an average follow-up of 16.2 months (range 12-24 months), patients were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) scoring system, Foot and Ankle Ability Measure (FAAM), and the visual analogue scale (VAS) for pain. RESULTS: At baseline, AOFAS and FAAM scores were similar in the two groups, whereas pain scores (VAS) were higher in those who were assigned to combined treatment. Despite the latter finding, the combined treatment with PRP resulted in better outcomes in terms of functional scores [AOFAS, 89.2 ± 3.9 vs. 71.0 ± 10.2, (p = 0.001); FAAM overall pain domain, 1.0 (1.0-2.0) vs. 2.5 (1.0-4.0), (p = 0.04); FAAM 15-min walking domain, 1.0 (1.0-2.0) vs. 2.0 (1.0-4.0) (p = 0.001)]; and pain-related scores [VAS, 2.2 ± 0.8 vs. 3.8 ± 1.2, (p = 0.001)] as compared to arthroscopic microfracture surgery alone. CONCLUSIONS: PRP as an adjunct to arthroscopic microfracture surgery for the treatment of osteochondral lesions of the talus resulted in improved functional score status in the medium-term. Further studies to determine the long-term efficacy of this approach were warranted. LEVEL OF EVIDENCE: II.