Reduced plasmalogen concentration as a surrogate marker of oxidative stress in elderly septic patients.

Severe sepsis is reportedly accompanied by oxidative stress with a depletion of antioxidant defense. We estimated plasmalogen vinyl ether bond (PVEB) levels in blood plasma of 20 elderly patients with initial severe sepsis, serving as a sensitive surrogate marker of oxidative stress, and compared them with standard markers, i.e., Acute Physiology and Chronic Health Evaluation (APACHE) II score, C-reactive protein (CRP), creatinine, white blood cell and platelet counts. Patients were included in the study and then blood samples were taken within 24h of the onset of symptoms of severe sepsis. Twenty sex- and age-matched, healthy individuals were included in the study as controls. We measured plasmalogen-derived hexadecanal dimethyl acetal (16:0 DMA) in isolated phospholipids from EDTA-plasma using gas chromatography. We found a 55% lower concentration of 16:0 DMA, corresponding to lower levels of PVEB in the patients' plasma compared to the controls (0.26±0.15 vs 0.58±0.13g/100g; p<0.001). In all patients' and non-survivors' samples the 16:0 DMA levels correlated negatively with plasma CRP values (RS=-0.48 and RS=-0.70, respectively; p<0.05), but not with APACHE II scores or other markers. The observed lower baseline content of PVEB may indicate oxidative stress contributing to the sequlae of sepsis, but did not correlate with the outcome or the severity of illness. Serial measurements are needed to validate PVEB as a marker in sepsis.

Decreased concentrations of serum phospholipid plasmalogens indicate oxidative burden of uraemic patients undergoing haemodialysis.

Experimental evidence indicates that uraemic patients undergoing haemodialysis are subject to increased oxidative stress. Plasmalogens are a phospholipid subclass found in cell membranes and plasma lipoproteins, which may work as an endogenous antioxidant. Using gas chromatography, we measured reduced portions of fatty aldehyde dimethyl acetals (16:0 DMA and 18:0 DMA, representing derivatives of plasmalogens) in fatty acid patterns of fasting serum phospholipids from 30 patients with chronic renal failure (CRF) receiving repeated ambulatory haemodialysis, as compared to 99 normal control subjects (CS). The highly significant difference of mean 16:0 DMA and 18:0 DMA values between CRF patients and CS (0.53 +/- 0.15 vs. 0.67 +/- 0.13, p < 0.001 and 0.33 +/- 0.11 vs. 0.40 +/- 0.11, p < 0.01, respectively) was lost when the patients were compared to subjects older than 85 (16:0 DMA) or 75 years (18:0 DMA). Weak, but significant inverse correlations with age or triglycerides were observed in blood serum of CS for 16:0 DMA and 18:0 DMA, respectively, but not of the patients. Partial correlation analysis indicated a mutually independent association of age and triglyceride values with serum plasmalogens in CS, but not in CRF patients. In conclusion, the reduced content of serum plasmalogen phospholipids of uraemic patients undergoing haemodialysis suggests an increased oxidative stress.