Basic research
The relationship between high-density lipoprotein, bacterial lipopolysaccharide, and tumour necrosis factor-α in patients with acute decompensated heart failure

Introduction:
We attempted to assess the relationship between serum lipoproteins and plasma concentrations of bacterial lipopolysaccharide (LPS, endotoxin), tumour necrosis factor-α (TNF-α) and soluble TNF receptor 1 and 2 (sTNF-R1 and 2) in patients with chronic heart failure (CHF). It has been shown that lipoproteins are able to act as endotoxin-binding proteins, thereby diminishing its bioactivity to induce inflammatory cytokine release.

Material and methods: Endotoxin, cytokines and lipoproteins were measured in 25 CHF patients (age 68±2 years) and 10 healthy controls (age 60±6, all mean ±SE). CHF patients were divided in oedematous (n=10) and non-oedematous (n=15) according to standard criteria. Interrelationships between endotoxin, cytokines and lipoproteins were analyzed.

Results: Oedematous patients had the highest endotoxin (P<0.05), TNF-α (P<0.001), sTNF-R1 and sTNF-R2 (both P<0.0001, all ANOVA), and lowest HDL (P<0.05, ANOVA). Amongst patients, HDL correlated with TNF-α (r=–0.60, P=0.002) and endotoxin (r=–0.50, P=0.01). The endotoxin/HDL ratio, indicating biologically active LPS, was highest in oedematous patients (P=0.005, ANOVA) and strongly related to TNF-α plasma concentrations (r=0.87, P<0.0001), independently of NYHA class (P<0.01), creatinine clearance (P=0.05), hepatic function, and age.

Conclusions: The degree of immune activation in oedematous CHF patients is related to endotoxaemia and inversely to serum HDL, suggesting an underlying relationship. This clinical observation supports previous experimental data and observational studies; hence further studies should explore its potential therapeutic use.