Redefining COVID-19 Severity and Prognosis: The Role of Clinical and Immunobiotypes.

Background: Most of the explanatory and prognostic models of COVID-19 lack of a comprehensive assessment of the wide COVID-19 spectrum of abnormalities. The aim of this study was to unveil novel biological features to explain COVID-19 severity and prognosis (death and disease progression). Methods: A predictive model for COVID-19 severity in 121 patients was constructed by ordinal logistic regression calculating odds ratio (OR) with 95% confidence intervals (95% CI) for a set of clinical, immunological, metabolomic, and other biological traits. The accuracy and calibration of the model was tested with the area under the curve (AUC), Somer's D, and calibration plot. Hazard ratios with 95% CI for adverse outcomes were calculated with a Cox proportional-hazards model. Results: The explanatory variables for COVID-19 severity were the body mass index (BMI), hemoglobin, albumin, 3-Hydroxyisovaleric acid, CD8+ effector memory T cells, Th1 cells, low-density granulocytes, monocyte chemoattractant protein-1, plasma TRIM63, and circulating neutrophil extracellular traps. The model showed an outstanding performance with an optimism-adjusted AUC of 0.999, and Somer's D of 0.999. The predictive variables for adverse outcomes in COVID-19 were severe and critical disease diagnosis, BMI, lactate dehydrogenase, Troponin I, neutrophil/lymphocyte ratio, serum levels of IP-10, malic acid, 3, 4 di-hydroxybutanoic acid, citric acid, myoinositol, and cystine. Conclusions: Herein, we unveil novel immunological and metabolomic features associated with COVID-19 severity and prognosis. Our models encompass the interplay among innate and adaptive immunity, inflammation-induced muscle atrophy and hypoxia as the main drivers of COVID-19 severity.

Dimethylguanidino Valerate: A Lifestyle-Related Metabolite Associated With Future Coronary Artery Disease and Cardiovascular Mortality.

Background Identification of lifestyle modifiable metabolic pathways related to cardiometabolic disease risk is essential for improvement of primary prevention in susceptible individuals. It was recently shown that plasma dimethylguanidino valerate (DMGV) levels are associated with incident type 2 diabetes mellitus. Our aims were to investigate whether plasma DMGV is related to risk of future coronary artery disease and with cardiovascular mortality and to replicate the association with type 2 diabetes mellitus and pinpoint candidate lifestyle interventions susceptible to modulate DMGV levels. Methods and Results Plasma DMGV levels were measured using liquid chromatography-mass spectrometry in a total of 5768 participants from the MDC (Malmö Diet and Cancer Study-Cardiovascular Cohort), MPP (Malmö Preventive Project), and MOS (Malmö Offspring Study). Dietary intake assessment was performed in the MOS. Baseline levels of DMGV associated with incident coronary artery disease in both the MDC (hazard ratio=1.29; CI=1.16-1.43; P<0.001) and MPP (odds ratio=1.25; CI=1.08-1.44; P=2.4e-3). In the MDC, DMGV was associated with cardiovascular mortality and incident coronary artery disease, independently of traditional risk factors. Furthermore, the association between DMGV and incident type 2 diabetes mellitus was replicated in both the MDC (hazard ratio=1.83; CI=1.63-2.05; P<0.001) and MPP (odds ratio=1.65; CI=1.38-1.98; P<0.001). Intake of sugar-sweetened beverages was associated with increased levels of DMGV, whereas intake of vegetables and level of physical activity was associated with lower DMGV. Conclusions We discovered novel independent associations between plasma DMGV and incident coronary artery disease and cardiovascular mortality, while replicating the previously reported association with incident type 2 diabetes mellitus. Additionally, strong associations with sugar-sweetened beverages, vegetable intake, and physical activity suggest the potential to modify DMGV levels using lifestyle interventions.

Determination of ß-hydroxy-ß-methylbutyrate concentration and enrichment in human plasma using chemical ionization gas chromatography tandem mass spectrometry.

Our objective was to develop a quick and simplified method for the determination of ß-Hydroxy-ß-methylbutyrate (HMB) and ɑ-ketoisocaproic acid (KIC) concentrations and enrichments by GC/MS/MS to determine the turnover rate of HMB in humans. In experiment 1, we provided a pulse of L-[5,5,5-2H3]leucine to younger adults in the postabsorptive state then collected blood samples over a 4h time period. In experiment 2, we provided a pulse of [3,4,methyl-13C3]HMB to older adults in the postabsorptive state then collected blood samples over a 3h time period. Plasma concentrations of KIC and HMB and MPE of KIC and HMB were determined by GC/MS/MS. Plasma enrichment of leucine was determined by LC/MS/MS. To determine plasma enrichment of [5,5,5-2H3]HMB and [3,4,methyl-13C3]HMB, samples were derivatized using pentafluorobenzyl bromide and analyzed using chemical ionization mode. The final methods used included multiple reaction monitoring of transitions 117.3>59.3 for M+0 and 120.3>59.3 for M+3. In experiment 1, peak MPE of Leu peaked at 9.76% generating a peak MPE of KIC at 2.67% and a peak HMB MPE of 0.3%. In experiment 2, the rate of appearance for HMB was 0.66µmol/kg ffm/h. We calculated that production of HMB in humans accounts for 0.66% of total leucine turnover.

Metabolomic profiling of serum from human pancreatic cancer patients using 1H NMR spectroscopy and principal component analysis.

Pancreatic cancer is a malignant tumor with the worst prognosis among all cancers. At the time of diagnosis, surgical cure is no longer a feasible option for most patients, thus early detection of pancreatic cancer is crucial for its treatment. Metabolomics is a powerful new analytical approach to detect the metabolome of cells, tissue, or biofluids. Here, we report the application of (1)H nuclear magnetic resonance (NMR) combined with principal components analysis to discriminate pancreatic cancer patients from healthy controls based on metabolomic profiling of the serum. The metabolic analysis revealed significant lower of 3-hydroxybutyrate, 3-hydroxyisovalerate, lactate, and trimethylamine-N-oxide as well as significant higher level of isoleucine, triglyceride, leucine, and creatinine in the serum from pancreatic cancer patients compared to that of healthy controls. Our data demonstrate that the subtle differences in metabolite profiles in serum of pancreatic cancer patients and that of healthy subjects as a result of physiological and pathological variations could be identified by NMR-based metabolomics and exploited as metabolic markers for the early detection of pancreatic cancer.

Analysis of beta-hydroxy-beta-methyl butyrate in plasma by gas chromatography and mass spectrometry.

A method for measuring the branched chain hydroxy acid beta-hydroxy-beta-methyl butyrate (HMB, a product of leucine catabolism) has been described. A [2H6]HMB internal standard was added to plasma and standards, and samples were extracted with diethyl ether, backextracted into neutral phosphate, dried, and derivatized for gas chromatography and mass spectrometry. The natural HMB was monitored at 175 amu and the deuterated HMB was monitored at 181 amu. Standard curves were linear to at least 25 microns and were quantitatively recovered from plasma. Basal concentrations of plasma HMB were from 1 to 2 microM in sheep and increased three- to fourfold when leucine's alpha-ketoacid (alpha-ketoisocaproate, KIC) was fed to lambs. This method can also be adapted to quantitate KIC and other branched chain ketoacids in plasma during the same run.

Fanconi syndrome in a patient with a variant of isovaleric acidemia.

Fanconi syndrome with proximal renal tubular acidosis is caused by a variety of anatomic, functional and metabolic disorders. We report a patient with a variant of isovaleric acidosis who developed proximal tubular acidosis. This patient was able to acidify the urine during metabolic acidosis, developed a hyperchloremic metabolic acidosis, and needed 24 mEq/kg/day of bicarbonate to maintain normal serum bicarbonate. She had a FE Bicarbonate of 12 +/- 4% during bicarbonate infusion. Isovaleric acidosis may be another toxic cause of proximal RTA.

The pancytopenia of isovaleric acidemia.

Severe pancytopenia developed in two infants with isovaleric acidemia. Previous reports indicate these hematologic abnormalities are a leading cause of death in affected infants. Our findings suggest that the pancytopenia may be due to arrested maturation of hematopoietic precursors. Prompt transfusion of appropriate blood components prevented complications due to the hematologic abnormalities.

Short chain fatty acids in plasma and brain: quantitative determination by gas chromatography.

A reliable and practicable method for the determination of short chain fatty acids in plasma and brain tissue is presented. The sample preparation by partition chromatography on silicic acid allows subsequently a quantitation of short chain fatty acids without interference by methylmalonic acid, or other more polar compounds. With the gas-chromatographic system 2-methylbutyrate is separated from isovalerate. Reference values are given for plasma. The system is also useful in combination with mass spectrometry.

Gas chromatographic measurement of plasma levels of sodium valproate: tentative therapeutic range of a new anticonvulsant in the treatment of refractory epileptics.

1. A precise and rapid gas chromatographic method for the measurement of plasma sodium valproate concentrations is presented. 2. The extraction is a single step procedure, and is reproducible and linear throughout the concentration range encountered. 3. Clinical evaluation of the drug is presented in eighteen epileptics on the basis of the percentage of days on which subjects had seizures before and after sodium valproate therapy. 4. A tentative therapeutic range for sodium valproate is presented on the basis of plasma levels and therapeutic effect.

A rapid and sensitive gas-liquid chromatographic procedure for the micro determination of sodium valproate (sodium di-N-propylacetate) in plasma or serum.

A gas-liquid chromatographic procedure for the micro determination of sodium valproate is described. Valproic acid is extracted from acidified plasma or serum into n-heptane containing an internal standard (octanoic acid) and after phase separation an aliquot is analysed by gas-liquid chromatography. The procedure is rapid, reliable, sensitive and specific. It requires 25--50 microliter sample for a single estimation, has a detection threshold of less than 10 mumol/l, and is suitable for routine clinical use.

Determination of the anticonvulsant drug--dipropyl acetate (Epilim) in human plasma by gas chromatography.

A relatively simple gas chromatographic procedure is proposed for the analysis of the drug dipropylacetic acid in plasma. The compound is chromatographed, as the free acid after ether extraction. Prior to concentration of the solvent the acid is converted to its potassium salt, then regenerated to the free acid immediately before analysis.

The estimation of plasma valproate by gas-liquid chromatography.

A gas chromatographic method for the plasma assay of the anticonvulsant, sodium valproate, is described. Derivatization is not necessary. 200 microliter plasma are required for a single estimation. The method involves a chloroform extraction of valproate and the internal standard, cyclopentane carboxylic acid, from acidified plasma. Gas-liquid chromatography using the stationary phase 10% SP-216-PS gives complete separation of valproate and the internal standard in eight minutes. The limit of detection is 20 mumol valproate/1 plasma (equivalent to 40 pmol on column). This is well below the lower therapeutic plasma level. The between-run precision of the method indicates a variation for each sample within+/-3% of its mean value.

Rapid determination of valproate sodium in serum by gas-liquid chromatography.

A rapid and simple gas-liquid chromatographic procedure is described for the measurement of valproate sodium (sodium di-n-propylacetate) in serum. Valproate is extracted from serum by a micro-extraction method and chromatographed on a 10% Carbowax 6000 column using 2-ethyl-2-methyl-caproic acid as internal standard. The method is capable of measuring at least 2 microgram of valproate per milliliter serum.

[Rapid gas chromatographic method for determination of acetate in human plasma and hemodialysis baths (author's transl)]. / Dosage rapide par chromatographie en phase gazeuse de l'acétate dans le plasma et les bains d'hémodialyse de suppléance

A rapid and sensitive method for acetate determination in human plasma and in hemodialysis baths (dialysates) is going to become necessary owing to the extensive using of sodium acetate solution in hemodialysis. The gas chromatographic method reported here allows, in about 35 minutes, the precise and reproducible measurement of acetate concentrations ranging from 0.2 to 20 mmol/1. This method can be used to investigate the kinetics of acetate concentration variations in the blood of patients undergoing hemodialysis with sodium acetate solution and to evaluate the amount of acetate absorbed during this treatment.

Alterations in volatile free fatty acids of blood after hepatectomy.

Volatile free fatty acids (VFA) in blood increased approximately twofold in dogs subjected to total hepatectomy. The average total plasma VFA preoperatively was 1,585 mug percent and shortly before death, postoperatively, was 2,798 mug percent. The corresponding red cell concentrations were essentially the same. Acetic acid was 81 percent of the total VFA, propionic acid 7 percent, isobutyric acid 4 percent, butyric acid one percent, and isovaleric acid 5 percent. There was little or no isovalerate in red cells. The increments in the individual fatty acids after hepatectomy were highly variable, but the average increase with time was almost linear. The increase in VFA probably reflects an increased utilization of the branched-chain aminoacids by extrahepatic tissues.