Daily consumption of ketone ester, bis-octanoyl (R)-1,3-butanediol, is safe and tolerable in healthy older adults in a randomized, parallel arm, double-blind, placebo-controlled, pilot study.

OBJECTIVES: Ketone bodies are endogenous metabolites produced during fasting or a ketogenic diet that have pleiotropic effects on aging pathways. Ketone esters (KEs) are compounds that induce ketosis without dietary changes, but KEs have not been studied in an older adult population. The primary objective of this trial was to assess the tolerability and safety of KE ingestion in a cohort of older adults. DESIGN: Randomized, placebo-controlled, double-blinded, parallel-arm trial (NCT05585762). SETTING: General community, Northern California, USA. PARTICIPANTS: Community-dwelling older adults, independent in activities of daily living, with no unstable acute medical conditions (n = 30; M = 15, F = 15; age = 76 y, range 65-90 y) were randomized and n = 23 (M = 14, F = 9) completed the protocol. INTERVENTION: Participants were randomly allocated to consume either KE (25 g bis-octanoyl (R)-1,3-butanediol) or a taste, appearance, and calorie-matched placebo (PLA) containing canola oil daily for 12 weeks. MEASUREMENTS: Tolerability was assessed using a composite score from a daily log for 2-weeks, and then via a bi-weekly phone interview. Safety was assessed by vital signs and lab tests at screening and weeks 0, 4 and 12, along with tabulation of adverse events. RESULTS: There was no difference in the prespecified primary outcome of proportion of participants reporting moderate or severe nausea, headache, or dizziness on more than one day in a two-week reporting period (KE n = 2 (14.3% [90% CI = 2.6-38.5]); PLA n = 1 (7.1% [90% CI = 0.4-29.7]). Dropouts numbered four in the PLA group and two in the KE group. A greater number of symptoms were reported in both groups during the first two weeks; symptoms were reported less frequently between 2 and 12 weeks. There were no clinically relevant changes in safety labs or vital signs in either group. CONCLUSIONS: This KE was safe and well-tolerated in this study of healthy older adults. These results provide an initial foundation for use of KEs in clinical research with older adults.

Diet, microbiome, and inflammation predictors of fecal and plasma short-chain fatty acids in humans.

BACKGROUND: Gut microbes produce short-chain fatty acids (SCFAs) which are associated with broad health benefits. However, it is not fully known how diet and/or the gut microbiome could be modulated to improve SCFA production. OBJECTIVE: To identify dietary, inflammatory, and/or microbiome predictors of SCFAs in a cohort of healthy adults. METHODS: SCFAs were measured in fecal and plasma samples from 359 healthy adults in the USDA Nutritional Phenotyping Study. Habitual and recent diet was assessed using a Food Frequency Questionnaire and ASA24 dietary recalls. Markers of systemic and gut inflammation were measured in fecal and plasma samples. The gut microbiome was assessed using shotgun metagenomics. Using statistics and machine learning, we determined how the abundance and composition of SCFAs varied with measures of diet, inflammation, and the gut microbiome. RESULTS: We show that fecal pH may be a good proxy for fecal SCFA abundance. A higher Healthy Eating Index for habitual diet was associated with a compositional increase in fecal butyrate, relative to acetate and propionate. SCFAs were associated with markers of subclinical GI inflammation. Fecal SCFA abundance was inversely related to plasma lipopolysaccharide binding protein. When we analyzed hierarchically organized diet and microbiome data with taxonomy-aware algorithms, we observed that diet and microbiome features were far more predictive of fecal SCFA abundances compared to plasma SCFA abundances. The top diet and microbiome predictors of fecal butyrate included potatoes and the thiamine biosynthesis pathway, respectively. CONCLUSION: These results suggest that resistant starch in the form of potatoes and microbially produced thiamine provide a substrate and essential cofactor, respectively, for butyrate synthesis. Thiamine may be a rate-limiting nutrient for butyrate production in adults. Overall, these findings illustrate the complex biology underpinning SCFA production in the gut. This trial was registered on clinicaltrials.gov as NCT02367287.

Role of the National Institute on Aging in Transforming Aging Research Through Geroscience and Gerotherapeutics-50 Years of Innovation.

This Viewpoint discusses the role of the National Institute on Aging (NIA) in the fields of geroscience and gerotherapeutics.

Unveiling the "hidden quality" of the walnut pellicle: a precious source of bioactive lipids.

Tree nut consumption has been widely associated with various health benefits, with walnuts, in particular, being linked with improved cardiovascular and neurological health. These benefits have been attributed to walnuts' vast array of phenolic antioxidants and abundant polyunsaturated fatty acids. However, recent studies have revealed unexpected clinical outcomes related to walnut consumption, which cannot be explained simply with the aforementioned molecular hallmarks. With the goal of discovering potential molecular sources of these unexplained clinical outcomes, an exploratory untargeted metabolomics analysis of the isolated walnut pellicle was conducted. This analysis revealed a myriad of unusual lipids, including oxylipins and endocannabinoids. These lipid classes, which are likely present in the pellicle to enhance the seeds' defenses due to their antimicrobial properties, also have known potent bioactivities as mammalian signaling molecules and homeostatic regulators. Given the potential value of this tissue for human health, with respect to its "bioactive" lipid fraction, we sought to quantify the amounts of these compounds in pellicle-enriched waste by-products of mechanized walnut processing in California. An impressive repertoire of these compounds was revealed in these matrices, and in notably significant concentrations. This discovery establishes these low-value agriculture wastes promising candidates for valorization and translation into high-value, health-promoting products; as these molecules represent a potential explanation for the unexpected clinical outcomes of walnut consumption. This "hidden quality" of the walnut pellicle may encourage further consumption of walnuts, and walnut industries may benefit from a revaluation of abundant pellicle-enriched waste streams, leading to increased sustainability and profitability through waste upcycling.

Compartment Syndrome Following Snake Envenomation in the United States: A Scoping Review of the Clinical Literature.

Introduction: Local tissue destruction following envenomation from North American snakes, particularly those within the Crotalinae subfamily, has the potential to progress to compartment syndrome. The pathophysiology of venom-induced compartment syndrome (VICS) is a debated topic and is distinct from trauma/reperfusion-induced compartment syndrome. Heterogeneity exists in the treatment practices of VICS, particularly regarding the decision to progress to fasciotomy. Associations with functional outcomes and evolution in clinical practice since the introduction of Crotalidae polyvalent immune Fab (FabAV) have not been well defined. Our goal was to identify the potential gaps in the literature regarding this phenomenon, as well as illuminate salient themes in the clinical characteristics and treatment practices of VICS. Methods: We conducted this systematic scoping-style review using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Records were included if they contained data surrounding the envenomation and hospital course of one or more patients who were envenomated by a snake species native to North America and were diagnosed with compartment syndrome from 1980-2020. Results: We included 19 papers: 10 single- or two-patient case reports encompassing 12 patients, and nine chart reviews providing summary statistics of the included patients. In case reports, the median compartment pressure when reported was 60 millimeters of mercury (interquartile range 55-68), 66% underwent fasciotomy, and functional outcomes varied. Use of antivenom appeared to be more liberal with FabAV than the earlier antivenin Crotalidae polyvalent. Rapid progression of swelling was the most commonly reported symptom. Among the included retrospective chart reviews, important data such as compartment pressures, consistent laboratory values, and snake species was inconsistently reported. Conclusions: Venom-induced compartment syndrome is relatively rare. Existing papers generally describe good outcomes even in the absence of surgical management. Significant gaps in the literature regarding antivenom dosing practices, serial compartment pressure measurements, and functional outcomes highlight the need for prospective studies and consistent standardized reporting.

The Undiagnosed Diseases Network: Characteristics of solvable applicants and diagnostic suggestions for non-accepted ones.

PURPOSE: Can certain characteristics identify as solvable some undiagnosed patients who seek extensive evaluation and thorough record review, like by the Undiagnosed Diseases Network (UDN)? METHODS: The UDN is a national research resource to solve medical mysteries through team science. Applicants provide informed consent to access to their medical records. After review, expert panels assess if applicants meet inclusion and exclusion criteria to select participants. When not accepting applicants, UDN experts may offer suggestions for diagnostic efforts. Using minimal information from initial applications, we compare features in applicants not accepted with those accepted and either solved or still not solved by the UDN. The diagnostic suggestions offered to non-accepted applicants and their clinicians were tallied. RESULTS: Non-accepted applicants were more often female, older at first symptoms and application, and longer in review than accepted applicants. The accepted and successfully diagnosed applicants were younger in ages, shorter in review time, more often non-white, of Hispanic ethnicity, and presenting with nervous system features. Half of non-accepted applicants were given suggestions for further local diagnostic evaluation. A few seemed to have two major diagnoses or a provocative environmental exposure history. CONCLUSION: Comprehensive UDN record review generates possibly helpful advice.

Peripheral inflammation is associated with brain atrophy and cognitive decline linked to mild cognitive impairment and Alzheimer's disease.

Inflammation is an important factor in Alzheimer's disease (AD). An NMR measurement in plasma, glycoprotein acetyls (GlycA), captures the overall level of protein production and glycosylation implicated in systemic inflammation. With its additional advantage of reducing biological variability, GlycA might be useful in monitoring the relationship between peripheral inflammation and brain changes relevant to AD. However, the associations between GlycA and these brain changes have not been fully evaluated. Here, we performed Spearman's correlation analyses to evaluate these associations cross-sectionally and determined whether GlycA can inform AD-relevant longitudinal measurements among participants in the Alzheimer's Disease Neuroimaging Initiative (n = 1506), with additional linear models and stratification analyses to evaluate the influences of sex or diagnosis status and confirm findings from Spearman's correlation analyses. We found that GlycA was elevated in AD patients compared to cognitively normal participants. GlycA correlated negatively with multiple concurrent regional brain volumes in females diagnosed with late mild cognitive impairment (LMCI) or AD. Baseline GlycA level was associated with executive function decline at 3-9 year follow-up in participants diagnosed with LMCI at baseline, with similar but not identical trends observed in the future decline of memory and entorhinal cortex volume. Results here indicated that GlycA is an inflammatory biomarker relevant to AD pathogenesis and that the stage of LMCI might be relevant to inflammation-related intervention.

ABCA1 and apoA-I dependent 12-hydroxyeicosatetraenoic acid efflux regulates macrophage inflammatory signaling.

Aberrant high-density lipoprotein (HDL) function is implicated in inflammation-associated pathologies. While HDL ABCA1-mediated reverse cholesterol and phospholipid transport are well described, the movement of pro-/anti-inflammatory lipids has not been explored. HDL phospholipids are the largest reservoir of circulating arachidonic acid-derived oxylipins. Endotoxin-stimulation activates inflammatory cells leading to hydroxyeicosatetraenoic acid (HETE) production, oxylipins which are involved in inflammatory response coordination. Active signaling in the non-esterified (NE) pool is terminated by sequestration of HETEs as esterified (Es) forms and degradation. We speculate that an ABCA1-apoA-I-dependent efflux of HETEs from stimulated cells could regulate intracellular HETE availability. Here we test this hypothesis both in vitro and in vivo. In endotoxin-stimulated RAW-264.7 macrophages preloaded with d8-arachidonic acid we use compartmental tracer modeling to characterize the formation of HETEs, and their efflux into HDL. We found that in response to endotoxin: I) Cellular NE 12-HETE is positively associated with MCP-1 secretion (p<0.001); II) HETE transfer from NE to Es pools is ABCA1-depedent (p<0.001); III) Cellular Es HETEs are transported into media when both apoA-I and ABCA1 are present (p<0.001); IV) The stimulated efflux of HETEs >> arachidonate (p<0.001). Finally, in endotoxin challenged humans (n=17), we demonstrate that intravenous lipopolysaccharide (0.6 ng/kg body weight) resulted in accumulation of 12-HETE in HDL over a 168-hour follow-up. Therefore, HDL can suppress inflammatory responses in macrophages by regulating intracellular HETE content in an apoA-I/ABCA1 dependent manner. The described mechanism may apply to other oxylipins and explain anti-inflammatory properties of HDL. This newly defined HDL property opens new doors for the study of lipoprotein interactions in metabolic diseases.

Metabolic Responses to an Acute Glucose Challenge: The Differential Effects of Eight Weeks of Almond vs. Cracker Consumption in Young Adults.

This study investigated the dynamic responses to an acute glucose challenge following chronic almond versus cracker consumption for 8 weeks (clinicaltrials.gov ID: NCT03084003). Seventy-three young adults (age: 18-19 years, BMI: 18-41 kg/m2) participated in an 8-week randomized, controlled, parallel-arm intervention and were randomly assigned to consume either almonds (2 oz/d, n=38) or an isocaloric control snack of graham crackers (325 kcal/d, n=35) daily for 8 weeks. Twenty participants from each group underwent a 2-hour oral glucose tolerance test (oGTT) at the end of the 8-week intervention. Metabolite abundances in the oGTT serum samples were quantified using untargeted metabolomics, and targeted analyses for free PUFAs, total fatty acids, oxylipins, and endocannabinoids. Multivariate, univariate, and chemical enrichment analyses were conducted to identify significant metabolic shifts. Findings exhibit a biphasic lipid response distinguished by higher levels of unsaturated triglycerides in the earlier periods of the oGTT followed by lower levels in the latter period in the almond versus cracker group (p-value<0.05, chemical enrichment analyses). Almond (vs. cracker) consumption was also associated with higher AUC120 min of aminomalonate, and oxylipins (p-value<0.05), but lower AUC120 min of L-cystine, N-acetylmannosamine, and isoheptadecanoic acid (p-value<0.05). Additionally, the Matsuda Index in the almond group correlated with AUC120 min of CE 22:6 (r=-0.46; p-value<0.05) and 12,13 DiHOME (r=0.45; p-value<0.05). Almond consumption for 8 weeks leads to dynamic, differential shifts in response to an acute glucose challenge, marked by alterations in lipid and amino acid mediators involved in metabolic and physiological pathways.

Ketogenic diet administration later in life improves memory by modifying the synaptic cortical proteome via the PKA signaling pathway in aging mice.

Aging compromises brain function leading to cognitive decline. A cyclic ketogenic diet (KD) improves memory in aged mice after long-term administration; however, short-term effects later in life and the molecular mechanisms that govern such changes remain unclear. Here, we explore the impact of a short-term KD treatment starting at elderly stage on brain function of aged mice. Behavioral testing and long-term potentiation (LTP) recordings reveal that KD improves working memory and hippocampal LTP. Furthermore, the synaptosome proteome of aged mice fed a KD long-term evidence changes predominantly at the presynaptic compartment associated to the protein kinase A (PKA) signaling pathway. These findings were corroborated in vivo by western blot analysis, with high BDNF abundance and PKA substrate phosphorylation. Overall, we show that a KD modifies brain function even when it is administered later in life and recapitulates molecular features of long-term administration, including the PKA signaling pathway, thus promoting synaptic plasticity at advanced age.

A randomized open-label, observational study of the novel ketone ester, bis octanoyl (R)-1,3-butanediol, and its acute effect on ß-hydroxybutyrate and glucose concentrations in healthy older adults.

Bis-octanoyl (R)-1,3-butanediol (BO-BD) is a novel ketone ester (KE) ingredient which increases blood beta-hydroxybutyrate (BHB) concentrations rapidly after ingestion. KE is hypothesized to have beneficial metabolic effects on health and performance, especially in older adults. Whilst many studies have investigated the ketogenic effect of KE in young adults, they have not been studied in an exclusively older adult population, for whom age-related differences in body composition and metabolism may alter the effects. This randomized, observational, open-label study in healthy older adults (n = 30, 50% male, age = 76.5 years, BMI = 25.2 kg/m2) aimed to elucidate acute tolerance, blood BHB and blood glucose concentrations for 4 hours following consumption of either 12.5 or 25 g of BO-BD formulated firstly as a ready-to-drink beverage (n = 30), then as a re-constituted powder (n = 21), taken with a standard meal. Both serving sizes and formulations of BO-BD were well tolerated, and increased blood BHB, inducing nutritional ketosis (≥ 0.5mM) that lasted until the end of the study. Ketosis was dose responsive; peak BHB concentration (Cmax) and incremental area under the curve (iAUC) were significantly greater with 25 g compared to 12.5 g of BO-BD in both formulations. There were no significant differences in Cmax or iAUC between formulations. Blood glucose increased in all conditions following the meal; there were no consistent significant differences in glucose response between conditions. These results demonstrate that both powder and beverage formulations of the novel KE, BO-BD, induce ketosis in healthy older adults, facilitating future research on functional effects of this ingredient in aging.

War veterans, minorities and crisis points in Yugoslav welfare.

This article provides an analytical overview of welfare policymaking and provision in the twentieth century in Yugoslavia at three decisive historical junctures. Those are: the Kingdom of Yugoslavia after the First World War; the socialist state after 1945; and the rump 'Yugoslavia' after the break-up of the state in 1991. In each of these periods welfare policies were crisis-driven, a response to massive social and economic upheaval caused by war, but they were also a reflection, of course, of the political ideals and the values of the state in which they were formed. The authors argue that the Yugoslav welfare state in its various incarnations was in part a response to socio-economic crisis caused by war, in part a mediation and an adaptation of the welfare regime it replaced (rather than a complete tabula rasa), and in part an articulation of the aspirations for national politics and citizenship held by the incoming leadership of the state. This comparative study of three important moments in Yugoslavia's welfare history, then, offers an opportunity to look anew at the social history of the state itself. Study of the Yugoslav welfare model, or rather models, helps us understand the larger political transformations that were bound up in the lifespan of the South Slav state, how the state thought about and created minorities through welfare regimes, and how welfare policies withstood (or not) socio-economic crisis.

Illuminating the function of the orphan transporter, SLC22A10, in humans and other primates.

SLC22A10 is an orphan transporter with unknown substrates and function. The goal of this study is to elucidate its substrate specificity and functional characteristics. In contrast to orthologs from great apes, human SLC22A10, tagged with green fluorescent protein, is not expressed on the plasma membrane. Cells expressing great ape SLC22A10 orthologs exhibit significant accumulation of estradiol-17ß-glucuronide, unlike those expressing human SLC22A10. Sequence alignments reveal a proline at position 220 in humans, which is a leucine in great apes. Replacing proline with leucine in SLC22A10-P220L restores plasma membrane localization and uptake function. Neanderthal and Denisovan genomes show proline at position 220, akin to modern humans, indicating functional loss during hominin evolution. Human SLC22A10 is a unitary pseudogene due to a fixed missense mutation, P220, while in great apes, its orthologs transport sex steroid conjugates. Characterizing SLC22A10 across species sheds light on its biological role, influencing organism development and steroid homeostasis.

Daily consumption of ketone ester, bis-octanoyl (R)-1,3-butanediol, is safe and tolerable in healthy older adults, a randomized, parallel arm, double-blind, placebo-controlled, pilot study.

Objectives: Ketone bodies are endogenous metabolites produced during fasting or a ketogenic diet that have pleiotropic effects on aging pathways. Ketone esters (KEs) are compounds that induce ketosis without dietary changes, but KEs have not been studied in an older adult population. The primary objective of this trial was to determine tolerability and safety of KE ingestion in older adults. Design: Randomized, placebo-controlled, double-blinded, parallel-arm trial, with a 12-week intervention period ( NCT05585762 ). Setting: General community, Northern California, USA. Participants: Community-dwelling older adults, independent in activities of daily living, with no unstable acute medical conditions (n=30) were randomized and n=23 (M= 14, F=9) completed the protocol. Intervention: Participants were randomly allocated to consume either KE (bis-octanoyl (R)-1,3-butanediol) or a taste, appearance, and calorie-matched placebo (PLA) containing canola oil. Measurements: Tolerability was assessed using a composite score from a daily log for 2-weeks, and then via a bi-weekly phone interview. Safety was assessed by vital signs and lab tests at screening and weeks 0, 4 and 12, along with tabulation of adverse events. Results: There was no difference in the prespecified primary outcome of proportion of participants reporting moderate or severe nausea, headache, or dizziness on more than one day in a two-week reporting period (KE n =2 (14.3% [90% CI = 2.6 - 38.5]); PLA n=1 (7.1% [90% CI = 0.4 - 29.7]). Dropouts numbered four in the PLA group and two in the KE group. A greater number of symptoms were reported in both groups during the first two weeks; symptoms were reported less frequently between 2 - 12 weeks. There were no clinically relevant changes in safety labs or vital signs in either group. Conclusions: This KE was safe and well-tolerated in healthy older adults. These results provide a foundation for use of KEs in aging research. Highlights: Ketones esters induce ketosis without dietary changes and may target aging biologyStudies of ketone esters were limited in duration and focused on younger adultsWe found ketone esters were safe and tolerable for 12 weeks in healthy older adults.

Pulmonary vascular disease in Veterans with post-deployment respiratory syndrome.

Exertional dyspnea has been documented in US military personnel after deployment to Iraq and Afghanistan. We studied whether continued exertional dyspnea in this patient population is associated with pulmonary vascular disease (PVD). We performed detailed histomorphometry of pulmonary vasculature in 52 Veterans with biopsy-proven post-deployment respiratory syndrome (PDRS) and then recruited five of these same Veterans with continued exertional dyspnea to undergo a follow-up clinical evaluation, including symptom questionnaire, pulmonary function testing, surface echocardiography, and right heart catheterization (RHC). Morphometric evaluation of pulmonary arteries showed significantly increased intima and media thicknesses, along with collagen deposition (fibrosis), in Veterans with PDRS compared to non-diseased (ND) controls. In addition, pulmonary veins in PDRS showed increased intima and adventitia thicknesses with prominent collagen deposition compared to controls. Of the five Veterans involved in our clinical follow-up study, three had borderline or overt right ventricle (RV) enlargement by echocardiography and evidence of pulmonary hypertension (PH) on RHC. Together, our studies suggest that PVD with predominant venular fibrosis is common in PDRS and development of PH may explain exertional dyspnea and exercise limitation in some Veterans with PDRS.

Associations of Systemic Inflammation and Senescent Cell Biomarkers with Clinical Outcomes in Older Adults with Schizophrenia.

Individuals with schizophrenia suffer from higher morbidity and mortality throughout life partly due to acceleration of aging-related diseases and conditions. Systemic inflammation is a hallmark of aging and is also observed in schizophrenia. An improved understanding of how inflammation and accelerated aging contribute to long-term health outcomes in schizophrenia could provide more effective treatments to preserve long-term cognitive and physical function. In this pilot cross-sectional study, 24 older adults (≥55 years old) with schizophrenia were assessed on symptoms (Positive and Negative Syndrome Scale), neurocognition (Matrics Consensus Cognitive Battery), mobility (Timed Get Up and Go), and general health (SF-12). Serum levels of 112 different cytokines were measured, from which we derived estimated senescence-associated secretory phenotype (SASP) scores for each participant. Two-tailed Pearson's bivariate correlations were computed to test the associations between schizophrenia clinical outcomes with individual cytokines, and SASP. Higher levels of eotaxin, IL-1α, IL-1ß, and IFNα are associated with both worse PANSS negative and depressive symptoms scores. IL-1α and IL-1ß negatively associated with general physical health whereas eotaxin negatively associated with mobility and global cognition. Overall, we found that specific inflammatory cytokines, but not composite measurements of SASP, are associated with clinical outcomes in older adults with schizophrenia.

Navigating the Landscape of Translational Geroscience in Canada: A Comprehensive Evaluation of Current Progress and Future Directions.

The inaugural Canadian Conferences on Translational Geroscience were held as 2 complementary sessions in October and November 2023. The conferences explored the profound interplay between the biology of aging, social determinants of health, the potential societal impact of geroscience, and the maintenance of health in aging individuals. Although topics such as cellular senescence, molecular and genetic determinants of aging, and prevention of chronic disease were addressed, the conferences went on to emphasize practical applications for enhancing older people's quality of life. This article summarizes the proceeding and underscores the synergy between clinical and fundamental studies. Future directions highlight national and global collaborations and the crucial integration of early-career investigators. This work charts a course for a national framework for continued innovation and advancement in translational geroscience in Canada.

Characterization of pediatric non-hematopoietic tumor metastases to the central nervous system: A single institution review.

Central nervous system (CNS) metastases represent a small portion of pediatric CNS neoplasms and data surrounding this condition with high morbidity is scarce. Single institutional archival institutional pathology records between 1999 and 2022 were searched for patients over 21 years old and younger with CNS, dura, cranial nerve, CSF, or leptomeningeal metastases; 41 cases were identified. We documented primary tumor types and locations, metastasis locations, types of invasion (direct extension vs distant metastasis), times from imaging or pathologic diagnosis to CNS involvement, and outcomes. Distant metastasis was the most common mechanism of metastasis (n = 32, 78%). Interval times to CNS metastasis varied by both tumor type and primary tumor location. In this cohort, osteosarcoma portended the shortest survival following CNS metastasis. This study highlights the diverse mechanisms and locations of CNS involvement in pediatric CNS metastases and illuminates a need for varied monitoring strategies when considering primary tumor type and anatomic location.

Effects of Preanalytical Sample Collection and Handling on Comprehensive Metabolite Measurements in Human Urine Biospecimens.

Epidemiology studies evaluate associations between the metabolome and disease risk. Urine is a common biospecimen used for such studies due to its wide availability and non-invasive collection. Evaluating the robustness of urinary metabolomic profiles under varying preanalytical conditions is thus of interest. Here we evaluate the impact of sample handling conditions on urine metabolome profiles relative to the gold standard condition (no preservative, no refrigeration storage, single freeze thaw). Conditions tested included the use of borate or chlorhexidine preservatives, various storage and freeze/thaw cycles. We demonstrate that sample handling conditions impact metabolite levels, with borate showing the largest impact with 125 of 1,048 altered metabolites (adjusted P < 0.05). When simulating a case-control study with expected inconsistencies in sample handling, we predicted the occurrence of false positive altered metabolites to be low (< 11). Predicted false positives increased substantially (³63) when cases were simulated to undergo alternate handling. Finally, we demonstrate that sample handling impacts on the urinary metabolome were markedly smaller than those in serum. While changes in urine metabolites incurred by sample handling are generally small, we recommend implementing consistent handling conditions and evaluating robustness of metabolite measurements for those showing significant associations with disease outcomes.