The Role of Physiological Vitamin C Concentrations on Key Functions of Neutrophils Isolated from Healthy Individuals.
Level 5 - mechanism / opinion, no new human data
In vitro laboratory experiment using primary human cells
PubMed 31212992 · doi:10.3390/nu11061363
What was done
Neutrophils were isolated from healthy human donors to evaluate the effect of physiological vitamin C concentrations (50–200 µmol/L ascorbate or dehydroascorbic acid) on cellular functions. The investigators measured intracellular ascorbate uptake, chemotaxis towards the chemoattractant fMLP, superoxide production, programmed cell death (phosphatidylserine exposure), and neutrophil extracellular trap (NET) formation in vitro.
What was found
Baseline neutrophils from healthy donors were already ascorbate-replete (0.35 nmol/10^6 cells) and did not take up additional extracellular ascorbate unless stimulated. Pre-loading with dehydroascorbic acid significantly increased intracellular ascorbate but did not alter superoxide production or chemotaxis. Extracellular ascorbate enhanced directional mobility toward fMLP. When cells were stimulated in the presence of ascorbate, intracellular ascorbate increased, phosphatidylserine exposure showed a non-significant increase, and NET formation was significantly attenuated. Specific numerical p-values and effect sizes were not reported in the abstract.
Why it matters
This study shows that even in vitamin C-replete healthy individuals, extracellular ascorbate under activating conditions can suppress NETosis and support directional migration, suggesting a potential mechanism by which physiological vitamin C could modulate inflammation and tissue damage.
Limits
The abstract does not disclose the sample size (number of blood donors). Findings are derived entirely from in vitro cell culture assays and cannot be directly extrapolated to in vivo immune responses or clinical outcomes without clinical trial validation.
Cited by
- supports Neutrophils and leukocytes maintain intracellular vitamin C concentrations 50 to 100 times higher than plasma concentrations.