Lipopolysaccharide-Binding Protein: A New Biomarker for Infectious Endocarditis?

Abstract

Background: Infectious endocarditis (IE) is a bacterial infection of the endocardium. Diagnosis is based on results obtained from echocardiography, blood cultures, and molecular genetic screening for bacteria and on data for inflammatory markers such as the leukocyte (WBC) count and the C-reactive protein (CRP) concentration. The aim of the present study was to evaluate lipopolysaccharide-binding protein (LBP) as a supportive biomarker for the diagnosis and therapeutic monitoring of IE. Methods: We measured LBP and CRP concentrations and WBC counts in 57 IE patients at hospital admission, 40 patients with noninfectious heart valve diseases (HVDs), and 55 healthy blood donors. The progression of these 3 markers and the influence of cardiac surgery on them were evaluated in 29 IE patients and 21 control patients. Results: Serum LBP concentrations were significantly higher in IE patients [mean (SD), 33.41 (32.10) mg/L] compared with HVD patients [6.67 (1.82) mg/L, P < 0.0001] and healthy control individuals [5.61 (1.20) mg/L]. The progression in the LBP concentration during therapy of IE patients correlated with the changes in the CRP concentration. The 2 markers were equally influenced by antibiotic treatment and surgical intervention. Conclusions: Serial LBP measurement may provide an effective and useful tool for evaluating the response to therapy in IE patients. We found a strong correlation between LBP and CRP concentrations; LBP has a tendency to increase earlier in cases of reinfection.

A systematic review of biomarkers in the diagnosis of infective endocarditis

“…Using Spearman's rank correlation, the study found a strong correlation between LBP and CRP concentrations (coefficient of 0.70). This study also found that LBP tended to increase at an earlier stage in cases of reinfection in IE-cases [27].…”

“…LBP correlated with the duration of antibiotic treatment, showing increased values in patients with IE compared to their two control groups with heart valve disease and healthy blood donors, respectively. Median LBP in IE-cases was significantly increased compared to controls with heart valve disease (33.41 mg/L vs. 6.67 mg/L) [27]. However, in another study the median LBP level did not vary significantly between IE patients (19 μg/mL) compared to healthy controls (15.8 μg/mL) [6].…”

“…Several studies in recent years, have presented the hypothesis that PCT might be a useful biomarker in IE cases. PCT-values tend to increase [11] 46 rejected IE [11] 21 [11] 2.3 ng/mL [11] 81/85 [11] 72/92 [11] Kryptor [11] NT-proBNP [17][18][19] Serum [17] No control group 125 [17] NA [17] NA [17] NA [17] Elecsys pro BNP assay [17] Plasma [18] 45 [18] 1500 pg/mL [18] 97/92 [18] NA [18] Elecsys pro BNP 2010 Analyzer [18] Blood [19] 45 [19] 400 pg/mL [19] NA [19] NA [19] NA [19] Cys C [17] Serum No control group 125 NA NA NA Modular P 2551 LBP [6,26,27] Serum [6] 71 IHD-patients [6] 63 [6] 15 μg/mL [6] NA [6] NA [6] ELISA [6] Serum [26] 156 matched blood donors [26] 78 [26] NA [26] NA [26] NA [26] IMMULITE LBP, LightCycler PCR [26] Serum …”

“…Its function is vital to the macrophage binding to the microorganism, inducing production of the proinflammatory cytokines IL-1, IL-6 and tumor necrosis factor-α (TNFα). Furthermore, LBP has also been investigated as a potential novel biomarker for IE [26,27]. A recent study assessed LBP in patients with IE finding an association with CRP, therapy response and surgery [27].…”

“…Furthermore, LBP has also been investigated as a potential novel biomarker for IE [26,27]. A recent study assessed LBP in patients with IE finding an association with CRP, therapy response and surgery [27]. LBP correlated with the duration of antibiotic treatment, showing increased values in patients with IE compared to their two control groups with heart valve disease and healthy blood donors, respectively.…”