Glucose "peak" and glucose "spike": Impact on endothelial function and oxidative stress.
Level 3 - non-randomized controlled study
Non-randomized controlled physiological human interventional study (clamp experiment)
PubMed 18950890 · doi:10.1016/j.diabres.2008.07.015
What was done
Investigators conducted stepwise euinsulinemic hyperglycemic clamps targeting 10 and 15 mmol/l glucose levels, with and without concurrent vitamin C infusion, in individuals with diabetes and healthy control subjects. In a second experiment, a 10 mmol/l hyperglycemic clamp was administered to two groups of diabetic patients categorized by different baseline fasting glucose concentrations. Endothelial function was assessed via flow-mediated dilation, and oxidative stress was evaluated by measuring plasma nitrotyrosine levels.
What was found
The abstract reports no numerical values, baseline participant characteristics, sample sizes, or p-values. Glucose elevations to 10 and 15 mmol/l produced concentration-dependent reductions in flow-mediated dilation and increases in nitrotyrosine, an effect counterbalanced by co-administration of vitamin C. Raising glucose to 10 mmol/l impaired endothelial function and elevated nitrotyrosine across both diabetic cohorts. When assessed as the change (delta) from baseline, patients starting with lower baseline fasting glucose experienced greater relative worsening in endothelial function and oxidative stress markers.
Why it matters
These findings suggest that the magnitude of an acute glucose surge relative to fasting levels (the glucose spike) may drive vascular oxidative stress and endothelial impairment, rather than absolute post-challenge glucose concentrations alone.
Limits
The abstract omits sample size, participant demographics, standard deviation metrics, and exact quantitative results. The study design lacks details regarding randomization or blinding, and the acute clamp setting does not establish long-term clinical cardiovascular outcomes.
Cited by
- partial Postprandial blood glucose spikes above 140 mg/dL cause arterial damage.