Functional Metabolomics\u27 Enhances Assessment of Tissue Dysfunction as Demonstrated in a Rat Model of Sub-Acute D-Serine Exposure

We describe a methodology that combines urinary metabolomics with a tissue-specific stressor administration to enhance assessment of tissue function. Kidney function in rats was mildly compromised with a sub-acute dose of D-serine and stressed with furosemide. NMR-based metabolomics analyses showed no detectable effects due to D-serine alone; but furosemide or D-serine + furosemide groups, classified separately from each other, and from control. Furosemide alone caused a ca. 2-fold increase in glucose, lactate, choline, and a 30% decrease in TCA intermediates (p≤0.05). D-serine suppressed these effects and produced a 1.7-fold increase in a p-phenolic acid-derivative of tyrosine (PAdY) relative to control (p≤0.05). The PAdY/tyrosine ratio increased 2-fold relative to rats given furosemide alone. D-serine effects were only detectable in furosemide-challenged rats, suggesting that minor disruption in kidney function, induced by low-level D-serine, is manifested by this functional metabolomics methodology. This technique may improve sensitivity for assessment of tissue function and diseas

A descriptive retrospective cohort study of thoracic surgery experiences from September 2015 to July 2017 at three referral hospitals in Rwanda

Background: Universal access to safe surgery is still a challenge in low- and middle-income countries. An insufficient surgical workforce is a major barrier for performing surgery in these settings, especially specialized operations, such as cardiac and thoracic surgeries. This article describes the thoracic surgical procedures performed at three referral hospitals in Rwanda. Methods: We conducted a retrospective cohort study involving patients with various chest pathologies operated by or under the supervision of a thoracic surgeon (faculty from the Human Resources for Health Program), at three teaching hospitals in Rwanda, from September 2015 through July 2017. This study included only major thoracic procedures. Data were collected from the faculty logbook and patient files. The information collected included demographic data, clinical presentation, radiological and intraoperative findings, and outcomes. Ethical approval was obtained from the University of Rwanda College of Medicine and Health Sciences Institutional Review Board. Results: Thirty-two patients underwent 33 operations during the 23 months of the study (1 patient had 2 procedures). Twenty-one of the patients (66%) were male, and 11 (34%) were female. Patients’ ages ranged between 13 and 77 years, with a mean age of 41 years. Infectious chest pathologies (mostly tuberculosis-related) were common indications for surgery. Sixteen cases (48%) were thoracic empyemas that required either thoracotomy and pulmonary decortication or open thoracostomy (modified Eloesser flap). Other operations performed were anterior mediastinotomy for mediastinal mass (4 cases), biopsy and resection of chest wall mass (3 cases), pericardial window for pericardial tamponade (2 cases), resection of lung aspergilloma (2 cases), resection of a lung tumour (2 cases), and others (4 cases). Mortality was 6% (2 patients), and 3 patients had postoperative complications, which were surgical site infection in 1 patient and ineffective thoracotomy in 2 patients. Conclusions: With clinical mentorship and dedicated teams, thoracic surgery can be performed in low-resource settings, where infectious pathologies predominate, with acceptable morbidity and mortality. Keywords: thoracic surgery; thoracostomy; tuberculosis; empyema; outcomes; complications; Rwanda

Evidence That Myo-Inositol Plus Ethanolamine Elevates Plasmalogen Levels And Lends Protection Against Oxidative Stress In Neuro-2A Cells

Plasmalogens are glycerophospholipids abundant in brain and heart tissues. Evidence suggests that they have antioxidant properties. Studies from our laboratory showed that rats treated with myo-inositol plus ethanolamine (ME) have elevated ethanolamine plasmalogens (PE-Pls) in brain and are protected against phosphine-induced oxidative stress. We hypothesized that ME elevates PE-Pls levels and protects against oxidative stress through oxidation of its vinyl ether bond. We tested this hypothesis in Neuro-2A cell culture and assessed the effects of treatments with myo-inositol (M), ethanolamine (Etn), or a combination (ME) on the: (1) effects on phospholipid (PL) classes, especially Etn PLs; (2) effects on cell viability in response to H2O2-induced oxidative stress; and (3) molecular species of Etn PLs preferentially affected by ME and H2O2 treatments, especially PE-Pls and their degradation byproducts – lyso-phosphatidylethanolamines (LPE). 31P NMR data show that treating the cells with equimolar amounts (500 uM) of M or Etn for 24 h did not influence PL levels, but ME yielded a 3-fold increase in both PE-Pls and PE (p\u3c0.001). Cells exposed to 650 uM H2O2 for 24 h decreased cell viability to 53% ± 1.7. While pretreatment with M or ME significantly increased cell survival to 62% ± 1.2 or 80% ± 0.6, respectively (p\u3c0.05), Etn alone had no effect. Mass spectrometry showed that ME preferentially elevated the levels of PE-Pls species containing saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) by 60%, while PE-Pls containing polyunsaturated fatty acids (PUFA) increased by only 10%. H2O2 caused a significant decrease in PE-Pls (27%), producing a 39% increase in LPE and a 4-fold increase in glycerophosphoethanolamine (GPE), but had no impact on PE levels, suggesting that LPE and GPE were primarily byproducts of PE-Pls degradation. Surprisingly, all these effects were blocked by pre-treating cells with ME prior to H2O2 exposure. Taken together, these data suggest that a preferential increase in PE-Pls species containing SFA+MUFA in response to ME may protect cells from H2O2-induced oxidative stress. The mechanism for this effect is unclear, but further investigations to understand these processes may help to develop neuroprotective approaches to alleviate the progression of neurodegenerative diseases/disorders

Furosemide Enhances the Sensitivity of Urinary Metabolomics for Assessment of Kidney Function

Introduction The ability of urinary metabolomics to detect meaningful, tissue-specific, biological effects (i.e., toxicity, disease) is compounded by high background variability. We hypothesize that sensitivity can be enhanced by imposing a tissue-targeted metabolic stressor. Objective We tested whether the sensitivity of metabolomics to assess kidney function is improved under the diuretic stress of furosemide. Methods To mildly compromise kidney, rats were given a sub-acute dose of d-serine. Then at 24 h postdose, we administered vehicle solution (control) or the diuretic drug, furosemide, and conducted NMR-based urinary metabolomics. Results Principal Components and OPLS discriminant analyses showed no effects on urinary profiles in rats receiving d-serine alone. However, the effects of d-serine were observable under furosemide-induced stress, as urinary profiles classified separately from rats receiving furosemide alone or vehicle-treated controls (p \u3c 0.001). Furthermore, this profile was uniquely different from a co-treatment effect observed following co-administration of d-serine + furosemide. We identified 24 metabolites to classify the effects of furosemide in normal rats vs. d-serine-compromised rats. Most notably, a furosemide-induced increase in urinary excretion of α-ketoglutarate, creatinine, trigonelline, and tryptophan in control rats, was significantly reduced in d-serine exposed rats (p \u3c 0.05). Interestingly, increased tryptophan metabolism has been shown to correlate with the severity of kidney transplant failure and chronic kidney disease. Conclusions We attribute these effects to differences in kidney function, which were only detectable under the stress imposed by furosemide. This technique may extend to other organ systems and may provide improved sensitivity for assessment of tissue function or early detection of disease

Furosemide Enhances the Sensitivity of Urinary Metabolomics for Assessment of Kidney Function

Introduction The ability of urinary metabolomics to detect meaningful, tissue-specific, biological effects (i.e., toxicity, disease) is compounded by high background variability. We hypothesize that sensitivity can be enhanced by imposing a tissue-targeted metabolic stressor. Objective We tested whether the sensitivity of metabolomics to assess kidney function is improved under the diuretic stress of furosemide. Methods To mildly compromise kidney, rats were given a sub-acute dose of d-serine. Then at 24 h postdose, we administered vehicle solution (control) or the diuretic drug, furosemide, and conducted NMR-based urinary metabolomics. Results Principal Components and OPLS discriminant analyses showed no effects on urinary profiles in rats receiving d-serine alone. However, the effects of d-serine were observable under furosemide-induced stress, as urinary profiles classified separately from rats receiving furosemide alone or vehicle-treated controls (p \u3c 0.001). Furthermore, this profile was uniquely different from a co-treatment effect observed following co-administration of d-serine + furosemide. We identified 24 metabolites to classify the effects of furosemide in normal rats vs. d-serine-compromised rats. Most notably, a furosemide-induced increase in urinary excretion of α-ketoglutarate, creatinine, trigonelline, and tryptophan in control rats, was significantly reduced in d-serine exposed rats (p \u3c 0.05). Interestingly, increased tryptophan metabolism has been shown to correlate with the severity of kidney transplant failure and chronic kidney disease. Conclusions We attribute these effects to differences in kidney function, which were only detectable under the stress imposed by furosemide. This technique may extend to other organ systems and may provide improved sensitivity for assessment of tissue function or early detection of disease

Urinary Metabolite Profiles May be Predictive of Cognitive Performance under Conditions of Acute Sleep Deprivation

Continuous and sustained actions in military and civilian operational environments typically lead to reduced sleep normally required to perform optimally. Because cognitive fatigue leading to defects in performance is an occupational hazard, there is a recognized need for real-time detection technologies that minimize cognitive fatigue-induced mishaps. Here, 23 individuals were subjected to 36 h of continuous wakefulness, and cognitive psychomotor vigilance and automated neuropsychological assessment metric tests were conducted over the last 24 h of wakefulness. Urine was collected prior to and during the cognitive testing period for metabolite analysis using proton NMR spectroscopy. Multivariate statistical analysis showed that temporal changes in urinary metabolite profiles mirrored cognitive performance during continuous wakefulness. Additionally, subjects identified by cognitive assessments as having a high tolerance (n=6) or low tolerance (n=6) to sleep deprivation could be classified separately with statistical confidence (

Urinary Metabolite Profiles May be Predictive of Cognitive Performance under Conditions of Acute Sleep Deprivation

Continuous and sustained actions in military and civilian operational environments typically lead to reduced sleep normally required to perform optimally. Because cognitive fatigue leading to defects in performance is an occupational hazard, there is a recognized need for real-time detection technologies that minimize cognitive fatigue-induced mishaps. Here, 23 individuals were subjected to 36 h of continuous wakefulness, and cognitive psychomotor vigilance and automated neuropsychological assessment metric tests were conducted over the last 24 h of wakefulness. Urine was collected prior to and during the cognitive testing period for metabolite analysis using proton NMR spectroscopy. Multivariate statistical analysis showed that temporal changes in urinary metabolite profiles mirrored cognitive performance during continuous wakefulness. Additionally, subjects identified by cognitive assessments as having a high tolerance (n=6) or low tolerance (n=6) to sleep deprivation could be classified separately with statistical confidence (

Metabolomics Characterization of U.S. and Japanese F-15 and C-130 Flight Line Crews Exposed to Jet Fuel Volatile Organic Compounds and Aerosols

Air and ground crews transfer a significant amount of jet fuel, and as a result of transfers, breathe its volatile emission from residues. Working on the flight line also exposes maintainers to exhaust from the jet fuel as engines are tested or run before and after flight. Since little is known concerning level of exposure and the corresponding biological response associated with human jet fuel exposure, nuclear magnetic resonance (NMR)-based metabolomics analysis of human urine was utilized for characterization of metabolite profiles of flight line personnel for potential biomarker discovery. This project was a collaborative research effort between the US Air Force (USAF) and the Japan Air Self-Defense Force(JASDF) to correlate flight line exposure to jet fuel volatile organic compounds (VOC)/exhaust with NMR-derived urinary metabolite profiles obtained from USAF personnel (JP-8 fueled aircraft) and Japanese personnel (JP-4 fueled aircraft) working F-15 and C-130 flight lines. Urine was collected from volunteers at USAF and JASDF air bases located in Japan preshift, postshift and the following morning. Metabolomics data suggested that urinary metabolite profiling may be a useful tool for monitoring flight line personnel exposures to hazardous chemicals.Incorporating select metadata (i.e. total VOC exposure, time on flight line, etc.) influenced NMR spectra to enhance the discriminatory power andaccuracy of the metabolomics data analysis. Additional work is still required to identify key metabolites that are predictive of exposure to jet fuels or combustion products

Metabolomics Characterization of U.S. and Japanese F-15 and C-130 Flight Line Crews Exposed to Jet Fuel Volatile Organic Compounds and Aerosols

Air and ground crews transfer a significant amount of jet fuel, and as a result of transfers, breathe its volatile emission from residues. Working on the flight line also exposes maintainers to exhaust from the jet fuel as engines are tested or run before and after flight. Since little is known concerning level of exposure and the corresponding biological response associated with human jet fuel exposure, nuclear magnetic resonance (NMR)-based metabolomics analysis of human urine was utilized for characterization of metabolite profiles of flight line personnel for potential biomarker discovery. This project was a collaborative research effort between the US Air Force (USAF) and the Japan Air Self-Defense Force(JASDF) to correlate flight line exposure to jet fuel volatile organic compounds (VOC)/exhaust with NMR-derived urinary metabolite profiles obtained from USAF personnel (JP-8 fueled aircraft) and Japanese personnel (JP-4 fueled aircraft) working F-15 and C-130 flight lines. Urine was collected from volunteers at USAF and JASDF air bases located in Japan preshift, postshift and the following morning. Metabolomics data suggested that urinary metabolite profiling may be a useful tool for monitoring flight line personnel exposures to hazardous chemicals.Incorporating select metadata (i.e. total VOC exposure, time on flight line, etc.) influenced NMR spectra to enhance the discriminatory power andaccuracy of the metabolomics data analysis. Additional work is still required to identify key metabolites that are predictive of exposure to jet fuels or combustion products

BIOMARKERS OF FATIGUE: Metabolomics Profiles Predictive of Cognitive Performance

Cognitive performance and fatigue are well known to be inversely related. Continuous and sustained actions in operational environments typically lead to reduced sleep normally required to perform optimally. These operational environments subject the warfighter to intense physical and mental exertion. Because fatigue continues to be an occupational hazard, leading to cognitive defects in performance, there has been a recognized need for real-time detection technologies that minimize fatigue-induced mishaps. I the current study, 23 subjects were subjected to 36h of sleep deprivation and cognitive psychomotor vigilance and automated neuropsychological assessment metric tests were conducted over the last 24 h of sleep deprivation. In addition, urine was collected prior to and over the course of the cognitive testing period for metabolite analysis using nuclear magnetic resonance (NMR) spectroscopy. Bioinformatics analysis of the NMR data identified 23 spectral resonances associated with specific urinary metabolites that could be used to classify subject fatigue susceptibility 12 h prior to cognitive testing and at 28 h of sleep deprivation on cognitive testing. Of these, 14 were found to statistically significant when associated with testing cognitive performance. A majority of these metabolites appeared to be associated with nutritional status and suggested that observed increases in dietary protein intake prior to cognitive testing led to increased cognitive performance when sleep deprived. NMR data were also found to correlate with previously reported psychological testing results of these same subjects. Taken together, our results indicate that a subset of urinary metabolites may provide a useful noninvasive biomarker screen for mission performance and readiness during sustained, demeaning missions