Cytidine-5-diphosphocholine reduces microvascular permeability during experimental endotoxemia

Abstract

Background: Microvascular permeability and leukocyte adhesion are pivotal mechanisms in sepsis pathophysiology contributing to the development of shock and mortality. No effective pharmacological therapy is currently available to restore microvascular barrier function in sepsis. Cholinergic mediators have been demonstrated to exert anti-inflammatory effects during inflammation. Cytidine-5-diphosphocholine (CDP-choline) is an extensively studied cholinergic drug due to its brain protective characteristics in cerebrovascular diseases. This study evaluated the effect of CDP-choline on microvascular permeability and leukocyte adhesion during endotoxemia.

Methods: Macromolecular leakage, leukocyte adhesion, and venular wall shear rate were examined in mesenteric postcapillary venules of rats by using intravital microscopy (IVM). Lipopolysaccharide (LPS) (4 mg/kg/h) or equivalent volumes of saline were continuously infused following baseline IVM at 0 min. IVM was repeated after 60 and 120 min in endotoxemic and nonendotoxemic animals. CDP-choline (100 mg/kg) was applied as an i.v. bolus. Animals received either saline alone, CDP-choline alone, CDP-choline 10 min before or 30 min after LPS administration, or LPS alone. Due to nonparametric data distribution, Wilcoxon test and Dunn's multiple comparisons test were used for data analysis. Data were considered statistically significant at p < 0.05.

Results: Treatment with LPS alone significantly increased microvascular permeability and leukocyte adhesion and decreased venular wall shear rate. CDP-choline significantly reduced microvascular permeability in animals treated with LPS. Leukocyte adhesion and venular wall shear rate were not affected by CDP-choline during endotoxemia.

Conclusion: CDP-choline has a protective effect on microvascular barrier function during endotoxemia. Considering the excellent pharmacologic safety profile of CDP-choline, its use could be an approach for the treatment of capillary leakage in sepsis.

Fig. 1

Experimental protocol. Intravital microscopic measurements (IVM) were performed at 0-, 60-, and 120- min in endotoxemic and nonendotoxemic animals following a stabilization period after surgical preparation. LPS (4 mg/kg/h) or an equivalent volume of saline was continuously infused starting directly after baseline IVM at 0 min. CDP-choline (100 mg/kg) was applied as an i.v. bolus in treatment groups. All administered fluids were calculated to guarantee that all animals received equal amounts of intravenous fluids. The color and number code of the experimental groups introduced in this figure is used in all other figures

Fig. 2

Effect of CDP-choline administration on macromolecular leakage during endotoxemia. Macromolecular leakage is expressed as ratio of perivenular to venular fluorescence intensity in arbitrary units. CDP-choline reduced microvascular permeability in postcapillary venules during endotoxemia. These results indicate that CDP-choline has a protective effect on microvascular permeability. Scatterplots with medians are displayed. *Significant difference vs. LPS (v). Medians with interquartile range (Q1–Q3) and p values are presented in Table 1

Fig. 3

IVM images demonstrating the CDP-choline effect on microvascular permeability during endotoxemia. Fluorescent IVM images show postcapillary venules recorded at 0 min (upper panels) and 120 min after the treatment (lower panels). LPS administration alone (v) induces distinctive macromolecular leakage compared to the baseline measurement at 0 min and to the NaCl group (i). Note the effect of CDP-choline on reducing macromolecular leakage in endotoxemic animals (iii, iv) compared to the LPS group (v)

Fig. 4

Effect of CDP-choline administration on leukocyte adherence during endotoxemia. CDP-choline had no effect on the number of adhering leukocytes during endotoxemia. Scatterplots with medians are displayed. * Significant difference vs. LPS (v). Medians with interquartile range (Q1–Q3) and p values are presented in Table 2