Increased Intraabdominal Pressure Impairs Liver Regeneration after Partial Hepatectomy in Rats Yavuz Kaya, M.D.,* Erinc Aral, M.D.,† Teoman Coskun, M.D.,* Nilufer Erkasap, M.D.,‡ and Ahmet Var, M.D.§ *Department of Surgery and §Department of Biochemistry, Celal Bayar University Faculty of Medicine, 45020 Manisa, Turkey; and †Department of Histology and Embryology and ‡Department of Physiology, Osmangazi University Faculty of Medicine, Eskisehir, Turkey Submitted for publication April 15, 2002 Background. There are many experimental studies showing that increased intraabdominal pressure (IAP) reduces liver blood flow, leading to ischemia and portal venous congestion. But, there is no study eval- uating the effect of increased IAP on liver regenera- tion. It is well known that acute liver ischemia and portal venous congestion impair liver regeneration. We, therefore, aimed to determine the effect of in- creased IAP on liver regeneration in this study. Methods. Sprague–Dawley rats underwent partial hepatectomy with or without IAP of 12–14 mm Hg for 24 h or sham operation. Rats were randomly divided into six groups: two sham-operated groups, two hepa- tectomy groups, and two hepatectomy with increased IAP groups. Mitotic index, proliferating cell nuclear antigen (PCNA)-labeling index, and liver regeneration rate as liver regeneration parameters were studied on day 1 or on day 4 after operation. Additionally, serum aspartate transaminase (AST) level and histopatholog- ical changes in intestinal mucosa were studied. Results. Hepatectomy with/without increased IAP groups had significantly higher serum AST levels than the sham-operated group on day 1. Serum AST level was found to be significantly higher in the hepatec- tomy with increased IAP group than in the other groups on day 4. Intestinal mucosal injury was found in the hepatectomy with increased IAP groups on days 1 and 4. Mitotic index and PCNA-labeling index were markedly higher in all hepatectomy with/without in- creased IAP groups than in the sham-operated groups. However, together with liver regeneration rate, both indices were significantly less in the hepatectomy with increased IAP groups than in the hepatectomy groups both on day 1 and on day 4. Conclusion. Maintenance of IAP between 12 and 14 mm Hg for 24 h impaired liver regeneration after par- tial hepatectomy in rats. © 2002 Elsevier Science (USA) Key Words: intraabdominal pressure; abdominal compartment syndrome; liver regeneration; partial hepatectomy. INTRODUCTION Increased intraabdominal pressure (IAP) is a com- mon problem encountered under many clinical condi- tions, such as abdominal trauma, liver transplanta- tion, and liver surgery secondary to trauma or cancer [1– 4]. The cardiovascular, respiratory, and renal ef- fects of increased IAP have been recognized for some time [5, 6]. Recently, the consequences of increased IAP on hepatic circulation as well as the splanchnic bed have attracted considerable attention. In experi- mental studies, mesenteric arterial, intestinal muco- sal, hepatic arterial, hepatic microcirculatory, and por- tal venous blood flow all have been shown to be reduced with increased IAP [5, 7–9]. In addition, it has been shown that increased IAP leads to significant increases in hepatic and portal vascular resistance [10]. Accord- ing to the results of these studies, increased IAP causes liver ischemia and portal venous congestion. It is well known that liver ischemia and/or portal venous conges- tion impairs liver regeneration after partial hepatec- tomy in experimental animals [11–13]. We, therefore, aimed to determine the effect of increased IAP on liver regeneration after partial hepatectomy in this experi- mental study. MATERIALS AND METHODS The procedures followed in this randomized experimental study were performed under aseptic condition and the protocol was ap- proved by the Institutional Committee for Animal Care and Guide- lines. Journal of Surgical Research 108, 250 –257 (2002) doi:10.1006/jsre.2002.6555 250 0022-4804/02 $35.00 © 2002 Elsevier Science (USA) All rights reserved.