Mortality and morbidity are significantly higher among patients with dialysis catheters, which has been associated with chronic activation of the immune system. We hypothesized that bacteria colonizing the catheter lumen trigger an inflammatory response. We aimed to evaluate the inflammatory profile of hemodialysis patients before and after locking catheters with an antimicrobial lock solution. High-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), IL-10, and tumor necrosis factor alpha (TNF-␣) were measured in serum, and levels of mRNA gene expression of IL-6, IL-10, and TNF-␣ were analyzed in peripheral blood mononuclear cells (PBMC). Samples were obtained at baseline and again after 3 months' use of taurolidinecitrate-heparin lock solution (TCHLS) in 31 hemodialysis patients. The rate of catheter-related bloodstream infections (CRBSI) was 1.08 per 1,000 catheter-days in the heparin period and 0.04 in the TCHLS period (P ؍ 0.023). Compared with the baseline data, serum levels of hs-CRP and IL-6 showed median percent reductions of 18.1% and 25.2%, respectively (P < 0.01), without significant changes in TNF-␣ or IL-10 levels. Regarding cytokine gene expression in PBMC, the median mRNA expression levels of TNF-␣ and IL-6 decreased by 20% (P < 0.05) and 19.7% (P ؍ 0.01), respectively, without changes in IL-10 expression levels. The use of TCHLS to maintain the catheter lumen sterility significantly reduces the incidence of CRBSI and improves the inflammatory profile in hemodialysis patients with tunneled catheters. Further studies are needed to evaluate the potential beneficial effects on clinical outcomes.
During the last few years, switching from a catheter to an arteriovenous fistula has been shown to be associated with a substantial decrease in mortality risk (1). Some authors have demonstrated that, even in the absence of catheter-related infection, patients receiving hemodialysis through a catheter had significantly higher serum concentrations of C-reactive protein, suggesting that chronic inflammation could be the reason for their significantly higher mortality rate (2-4). However, some patients are unable to have an arteriovenous fistula and it is therefore highly important to identify the mechanism through which catheters trigger a chronic inflammatory response even in the absence of clinically evident infection.The catheter lumen is colonized by microorganisms during its insertion or as a result of manipulating the hub (5). Once the microorganisms are attached to the intraluminal surface of the catheter, they embed themselves in a matrix of extracellular polymeric substances, thereby creating a biofilm (6). The maturation of this complex structure is a dynamic process that requires a chemically controlled detachment of biofilm fragments that starts after the third day of biofilm formation (7). Dittmer et al. (8) grew blood cultures from the catheter weekly after insertion in 31 patients with a central venous hemodialysis catheter. When the central cultures became positive, indicating cat...