Effects of chronic arterial hypertension on constitutive and induced ICAM-1 expression in the splanchnic organ

Abstract

• Effects of chronic arterial hypertension on constitutive and induced ICAM-1 expression in the splanchnic organs. S Komatsu, J Pan6s, MA Perry#, JM Russell, DN Granger Dept. Physiology, LSU Medical Center, Shreveport, LA 71130 #University of South Wales, Sydney, Australia Recent reports indicate that the endothelial cell adhesion molecule, ICAM-1 is upregnlated in response to endotoxin to a greater extent in cultured endothelial cells derived from spontaneously hypertensive (SHR) than cells norrnotensive (WKY) rats. it remains unknown whether such a difference occurs in vivo and whether vessels in splancbnic organs exhibit these altered responses in Chronically hypertensive animals. The objectives of this study were to characterize and compare the in vivo expression of ICAM-1 in SHR and WKY rats, under basal conditions and after exposure to endotoxin. Methods: ICAM-1 expression was studied in the splanchnic organs of untreated or eadotoxin-treated SHR and WKY rats at 5 hours after endotoxin administration (5mg/kg i.p.). ICAM-1 expression was measured using a25I labeled anti-rat ICAM-1 mAb (1A29), and an isotype matched control mAb: J3~I P-23 (anti-dog ICAM-1) to correct for nonspecific accumulation of the binding mAb. ICAM-1 corrected activity is expressed as (% injected activity ~25I-1A29./g) (% injected activity 13~I-P-23 Ig), Results: Constitutive expression of ICAM-1 was detected in all splanchnic organs. The levels of constitutive expression of ICAM-1 were similar in SHR and WKY. After endotoxin administration ICAM-1 expression significantly increased in all organs except the liver and spleen in both SHR and WKY rats. However, the magnitude of upregu!ation of ICAM1 in both the small and the large intestine was significantly lower in SHR than in WKY (small intestine 0.425-+0.020 vs. 0.527-+0.024 %/g, p<0.01; large intestine 0.317_+0.017 vs. 0.423+0.018 %/g, p<0.01, respectively ). No significant differences hi endotoxin-induced ICAM-1 apregulation were noted between the two groups for fiver, spleen, pancreas~ mesentery, and stomach. Conclusions: Chronic arterial hypertension does not affect constitutive expression of ICAM-1 in splanchnic organs, but is associated with a decreased endotoxin-induced upregnlation of the endothelial cell adhesion molecule in the small and large intestine.(Supported by DK43785) DISCRIMI ANT EFFECTS OF HEMORRHAGIC SHOCK ON PHAGOCYTIC CLEARANCE AND PHAGOCYTIC KILLING BY THE HEPATIC RETICULOENDOTHELIAL SYSTEM ~ , Dajie Wang, ToshJhiko Ma~am~ Andrew Klein and Gregory Bulkley. Dept of Surgery, the Johns Hopkins University, Baltimore, MD