Methylated Arginine Metabolites as Biomarkers for Clinical Status and Response to Type 5 Phosphodiesterase Inhibition in Patients With Fontan Circulation
Bibliographic record
Abstract
BACKGROUND: There is significant interest in NO pathway modulators, specifically type 5 phosphodiesterase inhibitors (PDE5is), to treat patients with a Fontan circulation. Trials, however, have had mixed results. The relationship between the NO pathway and clinical status in patients with Fontan circulation is a significant knowledge gap. METHODS AND RESULTS: We performed targeted metabolomic analysis using liquid chromatography coupled to mass spectrometry to quantify plasma NO pathway metabolite concentrations from 2 well-characterized populations of patients with Fontan circulation: the Boston Adult Congenital Heart Disease Biobank and Fontan Udenafil Exercise Longitudinal studies. We investigated associations between NO metabolite concentrations and clinical outcomes, exercise capacity, and response to PDE5is. Increased plasma concentration of asymmetric dimethyl arginine (ADMA), an inhibitor of NO production, was associated with risk for hospitalization or death. Increased ADMA and symmetric dimethyl arginine (another inhibitor of NO production) concentrations were associated with decreased baseline exercise capacity among patients with Fontan circulation with <90% predicted peak oxygen uptake, and change in ADMA and symmetric dimethyl arginine concentrations were predictive of change in exercise capacity over time. Treatment with the PDE5i udenafil uncoupled this association. Finally, baseline ADMA and symmetric dimethyl arginine concentrations predicted response to PDE5is among patients with subnormal peak oxygen uptake. CONCLUSIONS: Plasma concentrations of metabolites that inhibit NO flux are associated with negative clinical outcomes and worse exercise capacity. Moreover, metabolite shifts over time associated with increased NO flux are associated with improved exercise capacity. In patients with a Fontan circulation, the NO pathway modulators ADMA and symmetric dimethyl arginine may be useful as biomarkers of clinical status and predictive of response to PDE5is.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".