47 research outputs found
The SARS-CoV-2 viral load in COVID-19 patients is lower on face mask filters than on nasopharyngeal swabs.
Face masks and personal respirators are used to curb the transmission of SARS-CoV-2 in respiratory droplets; filters embedded in some personal protective equipment could be used as a non-invasive sample source for applications, including at-home testing, but information is needed about whether filters are suited to capture viral particles for SARS-CoV-2 detection. In this study, we generated inactivated virus-laden aerosols of 0.3-2 microns in diameter (0.9 µm mean diameter by mass) and dispersed the aerosolized viral particles onto electrostatic face mask filters. The limit of detection for inactivated coronaviruses SARS-CoV-2 and HCoV-NL63 extracted from filters was between 10 to 100 copies/filter for both viruses. Testing for SARS-CoV-2, using face mask filters and nasopharyngeal swabs collected from hospitalized COVID-19-patients, showed that filter samples offered reduced sensitivity (8.5% compared to nasopharyngeal swabs). The low concordance of SARS-CoV-2 detection between filters and nasopharyngeal swabs indicated that number of viral particles collected on the face mask filter was below the limit of detection for all patients but those with the highest viral loads. This indicated face masks are unsuitable to replace diagnostic nasopharyngeal swabs in COVID-19 diagnosis. The ability to detect nucleic acids on face mask filters may, however, find other uses worth future investigation
2-Pyrrolidinone and Succinimide as Clinical Screening Biomarkers for GABA-Transaminase Deficiency: Anti-seizure Medications Impact Accurate Diagnosis
Broad-scale untargeted biochemical phenotyping is a technology that supplements widely accepted assays, such as organic acid, amino acid, and acylcarnitine analyses typically utilized for the diagnosis of inborn errors of metabolism. In this study, we investigate the analyte changes associated with 4-aminobutyrate aminotransferase (ABAT, GABA transaminase) deficiency and treatments that affect GABA metabolism. GABA-transaminase deficiency is a rare neurodevelopmental and neurometabolic disorder caused by mutations in ABAT and resulting in accumulation of GABA in the cerebrospinal fluid (CSF). For that reason, measurement of GABA in CSF is currently the primary approach to diagnosis. GABA-transaminase deficiency results in severe developmental delay with intellectual disability, seizures, and movement disorder, and is often associated with death in childhood. Using an untargeted metabolomics platform, we analyzed EDTA plasma, urine, and CSF specimens from four individuals with GABA-transaminase deficiency to identify biomarkers by comparing the biochemical profile of individual patient samples to a pediatric-centric population cohort. Metabolomic analyses of over 1,000 clinical plasma samples revealed a rich source of biochemical information. Three out of four patients showed significantly elevated levels of the molecule 2-pyrrolidinone (Z-score ≥ 2) in plasma, and whole exome sequencing revealed variants of uncertain significance in ABAT. Additionally, these same patients also had elevated levels of succinimide or its ring-opened form, succinamic acid, in plasma, urine, and CSF and/or homocarnosine in urine and CSF. In the analysis of clinical EDTA plasma samples, the levels of succinamic acid and 2-pyrrolidinone showed a high level of correlation (R = 0.72), indicating impairment in GABA metabolism and further supporting the association with GABA-transaminase deficiency and the pathogenicity of the ABAT variants. Further analysis of metabolomic data across our patient population revealed the association of elevated levels of 2-pyrrolidinone with administration of vigabatrin, a commonly used anti-seizure medication and a known inhibitor of GABA-transaminase. These data indicate that anti-seizure medications may alter the biochemical and metabolomic data, potentially impacting the interpretation and diagnosis for the patient. Further, these data demonstrate the power of combining broad scale genotyping and phenotyping technologies to diagnose inherited neurometabolic disorders and support the use of metabolic phenotyping of plasma to screen for GABA-transaminase deficiency
IL‑6 Linkage to Exercise-Induced Shifts in Lipid-Related Metabolites: A Metabolomics-Based Analysis
Metabolomics profiling
and bioinformatics technologies were used
to determine the relationship between exercise-induced increases in
IL-6 and lipid-related metabolites. Twenty-four male runners (age
36.5 ± 1.8 y) ran on treadmills to exhaustion (2.26 ± 0.01
h, 24.9 ± 1.3 km, 69.7 ± 1.9% VO<sub>2max</sub>). Vastus
lateralis muscle biopsy and blood samples were collected before and
immediately after running and showed a 33.7 ± 4.2% decrease in
muscle glycogen, 39.0 ± 8.8-, 2.4 ± 0.3-, and 1.4 ±
0.1-fold increases in plasma IL-6, IL-8, and MCP-1, respectively,
and 95.0 ± 18.9 and 158 ± 20.6% increases in cortisol and
epinephrine, respectively (all, <i>P</i> < 0.001). The
metabolomics analysis revealed changes in 209 metabolites, especially
long- and medium-chain fatty acids, fatty acid oxidation products
(dicarboxylate and monohydroxy fatty acids, acylcarnitines), and ketone
bodies. OPLS-DA modeling supported a strong separation in pre- and
post-exercise samples (R2Y = 0.964, Q2Y = 0.902). OPLSR analysis failed
to produce a viable model for the relationship between IL-6 and all
lipid-related metabolites (R2Y = 0.76, Q2Y = −0.0748). Multiple
structure equation models were evaluated based on IL-6, with the best-fit
pathway model showing a linkage of exercise time to IL-6, then carnitine,
and 13-methylmyristic acid (a marker for adipose tissue lipolysis)
and sebacate. These metabolomics-based data indicate that the increase
in plasma IL-6 after long endurance running has a minor relationship
to increases in lipid-related metabolites
Untargeted metabolomics identifies unique though benign biochemical changes in patients with pathogenic variants in UROC1
Urocanic aciduria is caused by a deficiency in the enzyme urocanase (E.C. 4.2.1.49) encoded by the gene UROC1. In the past, deficiency of urocanase has been associated with intellectual disability in a few case studies with some suggestion that the enzyme deficiency was the causative etiology. Here, we describe two phenotypically normal siblings with compound heterozygous pathogenic variants in UROC1 and characteristic biochemical evidence of urocanase deficiency collected utilizing untargeted metabolomic analysis. These findings suggest that urocanic aciduria may represent an otherwise benign biochemical phenotype and that those individuals with concurrent developmental delay should continue to be evaluated for other underlying causes for their symptoms. Keywords: UROC1, Urocanic aciduria, Untargeted metabolomics, Cis-urocanate, Trans-urocanate, Imidazole propionat
Examination of physiological function and biochemical disorders in a rat model of prolonged asphyxia-induced cardiac arrest followed by cardio pulmonary bypass resuscitation.
Cardiac arrest induces whole body ischemia, which causes damage to multiple organs particularly the heart and the brain. There is clinical and preclinical evidence that neurological injury is responsible for high mortality and morbidity of patients even after successful cardiopulmonary resuscitation. A better understanding of the metabolic alterations in the brain during ischemia will enable the development of better targeted resuscitation protocols that repair the ischemic damage and minimize the additional damage caused by reperfusion.A validated whole body model of rodent arrest followed by resuscitation was utilized; animals were randomized into three groups: control, 30 minute asphyxial arrest, or 30 minutes asphyxial arrest followed by 60 min cardiopulmonary bypass (CPB) resuscitation. Blood gases and hemodynamics were monitored during the procedures. An untargeted metabolic survey of heart and brain tissues following cardiac arrest and after CPB resuscitation was conducted to better define the alterations associated with each condition.After 30 min cardiac arrest and 60 min CPB, the rats exhibited no observable brain function and weakened heart function in a physiological assessment. Heart and brain tissues harvested following 30 min ischemia had significant changes in the concentration of metabolites in lipid and carbohydrate metabolism. In addition, the brain had increased lysophospholipid content. CPB resuscitation significantly normalized metabolite concentrations in the heart tissue, but not in the brain tissue.The observation that metabolic alterations are seen primarily during cardiac arrest suggests that the events of ischemia are the major cause of neurological damage in our rat model of asphyxia-CPB resuscitation. Impaired glycolysis and increased lysophospholipids observed only in the brain suggest that altered energy metabolism and phospholipid degradation may be a central mechanism in unresuscitatable brain damage
Serum Metabolic Signatures Induced By a Three-Day Intensified Exercise Period Persist After 14 h of Recovery in Runners
This study investigated changes in
the human serum metabolome elicited
by a 3-day period of intensified training. Runners (<i>N</i> = 15, mean ± SD age, 35.2 ± 8.7 years) ran for 2.5 h/day
on treadmills at ∼70% VO<sub>2max</sub> for 3 days in a row,
with blood samples collected pre-exercise, and immediately and 14
h post-exercise. Samples were analyzed using gas and liquid chromatography/mass
spectrometry (GC–MS, LC–MS), with compounds identified
based on comparison to more than 2800 purified standards. Repeated
measures ANOVA was used to identify metabolites that differed significantly
across time, with multiple testing corrected by the false discovery
rate (FDR) (<i>q</i>-value). Immediately following the 3-day
exercise period, significant 2-fold or higher increases in 75 metabolites
were measured, with all but 22 of these metabolites related to lipid/carnitine
metabolism, 13 to amino acid/peptide metabolism, 4 to hemoglobin/porphyrin
metabolism, and 3 to Krebs cycle intermediates (<i>q</i>-values < 0.001). After a 14 h overnight recovery period, 50 of
the 75 metabolites remained elevated, with 8 decreased (primarily
amino acid-related metabolites) (<i>q</i>-values < 0.05).
Among the top 20 metabolites, the mean fold changes were 12.4 ±
5.3 and 2.9 ± 1.3 immediately and 14-h post-exercise, respectively.
Significant decreases (40–70%, <i>q</i> < 0.01)
in 22 metabolites (primarily related to lysolipid and bile acid metabolism)
were measured post-exercise, with all but 4 of these still decreased
after 14 h rest recovery (<i>q</i> < 0.025). Runners
experienced a profound systemic shift in blood metabolites related
to energy production especially from the lipid super pathway following
3 days of heavy exertion that was not fully restored to pre-exercise
levels after 14 h recovery
Metabolomics Study of the Effects of Inflammation, Hypoxia, and High Glucose on Isolated Human Pancreatic Islets
The transplantation of human pancreatic
islets is a therapeutic
possibility for a subset of type 1 diabetic patients who experience
severe hypoglycemia. Pre- and post-transplantation loss in islet viability
and function, however, is a major efficacy-limiting impediment. To
investigate the effects of inflammation and hypoxia, the main obstacles
hampering the survival and function of isolated, cultured, and transplanted
islets, we conducted a comprehensive metabolomics evaluation of human
islets in parallel with dynamic glucose-stimulated insulin release
(GSIR) perifusion studies for functional evaluation. Metabolomics
profiling of media and cell samples identified a total of 241 and
361 biochemicals, respectively. Metabolites that were altered in highly
significant manner in both included, for example, kynurenine, kynurenate,
citrulline, and mannitol/sorbitol under inflammation (all elevated)
plus lactate (elevated) and <i>N</i>-formylmethionine (depressed)
for hypoxia. Dynamic GSIR experiments, which capture both first- and
second-phase insulin release, found severely depressed insulin-secretion
under hypoxia, whereas elevated baseline and stimulated insulin-secretion
was measured for islet exposed to the inflammatory cytokine cocktail
(IL-1β, IFN-γ, and TNF-α). Because of the uniquely
large changes observed in kynurenine and kynurenate, they might serve
as potential biomarkers of islet inflammation, and indoleamine-2,3-dioxygenase
on the corresponding pathway could be a worthwhile therapeutic target
to dampen inflammatory effects
Conserved Metabolic Changes in Nondiabetic and Type 2 Diabetic Bariatric Surgery Patients: Global Metabolomic Pilot Study.
The goal of this study was to provide insight into the mechanism by which bariatric surgical procedures led to weight loss and improvement or resolution of diabetes. Global biochemical profiling was used to evaluate changes occurring in nondiabetic and type 2 diabetic (T2D) patients experiencing either less extreme sleeve gastrectomy or a full gastric bypass. We were able to identify changes in metabolism that were affected by standard preoperation liquid weight loss diet as well as by bariatric surgery itself. Preoperation weight-loss diet was associated with a strong lipid metabolism signature largely related to the consumption of adipose reserves for energy production. Glucose usage shift away from glycolytic pyruvate production toward pentose phosphate pathway, via glucose-6-phosphate, appeared to be shared across all patients regardless of T2D status or bariatric surgery procedure. Our results suggested that bariatric surgery might promote antioxidant defense and insulin sensitivity through both increased heme synthesis and HO activity or expression. Changes in histidine and its metabolites following surgery might be an indication of altered gut microbiome ecology or liver function. This initial study provided broad understanding of how metabolism changed globally in morbidly obese nondiabetic and T2D patients following weight-loss surgery
Serum caffeine (interaction effect, P<0.001; group contrast immediately-post-exercise, P = 0.0012, Q = 0.0626).
<p>Serum caffeine (interaction effect, P<0.001; group contrast immediately-post-exercise, P = 0.0012, Q = 0.0626).</p