LPS-induced microvascular leukocytosis can be assessed by blue-field entoptic phenomenon

• Published in: American journal of physiology. Heart and circulatory physiology 2004-08, Vol.287 (2), p.H691-H694
• Main Authors: Kolodjaschna, Julia, Berisha, Fatmire, Lung, Solveig, Schaller, Georg, Polska, Elzbieta, Jilma, Bernd, Wolzt, Michael, Schmetterer, Leopold
• Format: Article
• Language: English
• Subjects: Adult; Blood Flow Velocity - drug effects; Cell Movement; Erythrocytes - drug effects; Escherichia coli; Eye - blood supply; Humans; Laser-Doppler Flowmetry; Leukocyte Count; Leukocytosis - blood; Leukocytosis - chemically induced; Leukocytosis - pathology; Leukocytosis - physiopathology; Lipopolysaccharides - pharmacology; Male; Microcirculation - drug effects; Retinal Vessels - pathology; Retinal Vessels - physiopathology; Vasodilation
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.01240.2003

Departments of 1 Clinical Pharmacology and 2 Medical Physics, University of Vienna, A-1090 Vienna, Austria Submitted 31 December 2003 ; accepted in final form 27 February 2004 Administration of low doses of Escherichia coli endotoxin [a lipopolysaccharide (LPS)] to humans enables the study of inflammatory mechanisms. The purpose of the present study was to investigate whether the blue-field entoptic technique may be used to quantify the increase in circulating leukocytes in the ocular microvasculature after LPS infusion. In addition, combined laser Doppler velocimetry and retinal vessel size measurement were used to study red blood cell movement. Twelve healthy male volunteers received 20 IU/kg iv LPS as a bolus infusion. Outcome parameters were measured at baseline and 4 h after LPS administration. In the first protocol ( n = 6 subjects), ocular hemodynamic effects were assessed with the blue-field entoptic technique, the retinal vessel analyzer, and laser Doppler velocimetry. In the second protocol ( n = 6 subjects), white blood cell (WBC) counts from peripheral blood samples and blue-field entoptic technique measurements were performed. LPS caused peripheral blood leukocytosis and increased WBC density in ocular microvessels (by 49%; P = 0.036) but did not change WBC velocity. In addition, retinal venous diameter was increased (by 9%; P = 0.008), but red blood cell velocity remained unchanged. The LPS-induced changes in retinal WBC density and leukocyte counts were significantly correlated ( r = 0.87). The present study indicates that the blue-field entoptic technique can be used to assess microvascular leukocyte recruitment in vivo. In addition, our data indicate retinal venous dilation in response to endotoxin. ocular blood flow; inflammation; retinal vessel analyzer; laser Doppler velocimetry Address for reprint requests and other correspondence: L. Schmetterer, Dept. of Clinical Pharmacology, Währinger Gürtel 18-20, A-1090 Vienna, Austria (E-mail: Leopold.Schmetterer{at}univie.ac.at ).