AJP - Gastrointestinal and Liver Physiology

Uchinami, Hiroshi; Yamamoto, Yuzo; Kume, Makoto; Yonezawa, Kei; Ishikawa, Yasuhide; Taura, Kojiro; Nakajima, Akio; Hata, Koichiro; Yamaoka, Yoshio

doi: 10.1152/ajpgi.00466.2001pmid: 12016121

Abstract Hepatic ischemia-reperfusion (I/R) injury continues to be a fatal complication after liver surgery. Heat shock (HS) preconditioning is an effective strategy for protecting the liver from I/R injury, but its exact mechanism is still unclear. Because the activation of nuclear factor-κB (NF-κB) is an important event in the hepatic I/R-induced inflammatory response, the effect of HS preconditioning on the pathway for NF-κB activation was investigated. In the control group, NF-κB was activated 60 min after reperfusion, but this activation was suppressed in the HS group. Messenger RNA expressions of proinflammatory mediators during reperfusion were also reduced with HS preconditioning. Concomitant with NF-κB activation, NF-κB inhibitor I-κB proteins were degraded in the control group, but this degradation was suppressed in the HS group. This study shows that HS preconditioning protected the liver from I/R injury by suppressing the activation of NF-κB and the subsequent expression of proinflammatory mediators through the stabilization of I-κB proteins. hepatic ischemia-reperfusion nuclear factor-κB proinflammatory mediators Footnotes This work was partly supported by a Grant-in-Aid of the Japan Society for the Promotion of Science, Tokyo Japan (Nos. 12470258 and 13557105). Address for reprint requests and other correspondence: Y. Yamamoto, Dept. of Gastroenterological Surgery, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606–8507, Japan (E-mail: [email protected] ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. First published January 30, 2002;10.1152/ajpgi.00466.2001 Copyright © 2002 the American Physiological Society

Wang, Dongfang; Lehman, Richard E.; Donner, David B.; Matli, Mary R.; Warren, Robert S.; Welton, Mark L.

doi: 10.1152/ajpgi.00250.2001pmid: 12016135

Abstract Normal human colonic microvascular endothelial cells (HUCMEC) have been isolated from surgical specimens by their adherence to Ulex europaeus agglutinin bound to magnetic dynabeads that bind α- l -fucosyl residues on the endothelial cell membrane. Immunocytochemistry demonstrated the presence of a range of endothelial-specific markers on HUCMEC, including the von Willebrand factor, Ulex europaeus agglutinin, and platelet endothelial cell adhesion molecule-1. The growing cells form monolayers with the characteristic cobblestone morphology of endothelial cells and eventually form tube-like structures. HUCMEC produce vascular endothelial growth factor (VEGF) and express the receptors, kinase insert domain-containing receptor (KDR) and fms-like tyrosine kinase, through which VEGF mediates its actions in the endothelium. VEGF induces the tyrosine phosphorylation of KDR and a proliferative response from HUCMEC comparable to that elicited from human umbilical vein endothelial cells (HUVEC). On binding to HUCMEC or HUVEC, 125 I-labeled VEGF internalizes or dissociates to the medium. Once internalized, 125 I-labeled VEGF is degraded and no evidence of ligand recycling was observed. However, significantly less VEGF is internalized, and more is released to the medium from HUCMEC than HUVEC. Angiogenesis results from the proliferation and migration of microvascular, not large-vessel, endothelial cells. The demonstration that microvascular endothelial cells degrade less and release more VEGF to the medium than large-vessel endothelial cells identifies a mechanism permissive of the role of microvascular cells in angiogenesis. vascular endothelial growth factor colon Footnotes ↵ * R. Warren and M. Welton contributed equally to this work. This work was supported by National Institutes of Health Grant CA-84019 (to R. S. Warren). Address for reprint requests and other correspondence: R. S. Warren, U372, 533 Parnassus Ave., San Francisco, CA 94143-0790 (E-mail: [email protected] ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. First published January 2, 2002;10.1152/ajpgi.00250.2001 Copyright © 2002 the American Physiological Society

Moragoda, Lathika; Jaszewski, Richard; Kulkarni, Prasad; Majumdar, Adhip P. N.

doi: 10.1152/ajpgi.00312.2001pmid: 12016117

Abstract The current study is based on the hypothesis that aging predisposes gastric mucosa to carcinogenesis through altered expression and/or mutations of genes involved in cell growth. To test this hypothesis, we investigated the age-associated changes in mutation of adenomatous polyposis coli ( APC ), deleted in colorectal cancer ( DCC ), p53, and K- ras genes in the gastric mucosa of 19 healthy subjects of varying ages (25–91 yr). Specifically, we studied the loss of heterozygosity (LOH) of these genes in cardia, body, and antrum of the stomach. We observed that 3 of 19 subjects (16%) over 60 yr of age show LOH of at least one of the tumor suppressor genes. Among the subjects over 60 yr of age, the incidence of LOH is 38% (3/8). Two of three subjects had mutations in more than one tumor suppressor gene. In all three affected subjects, mutation in APC, DCC, or p53 was located mainly in the body of the stomach, suggesting increased susceptibility of this region to neoplastic changes. However, no LOH of K- ras was observed in these subjects. Our observation that subjects over 60 yr of age show mutation in one or more of the tumor suppressor genes suggests an age-related increase in predisposition of the stomach to neoplasia. aging mutations p53 adenomatous polyposis coli deleted in colorectal cancer K- ras neoplasia Footnotes Address for reprint requests and other correspondence: A. P. N. Majumdar, Research Service-151, VA Medical Center, 4646 John R, Detroit, MI 48201 (E-mail: [email protected] ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. First published January 30, 2002;10.1152/ajpgi.00312.2001 Copyright © 2002 the American Physiological Society

Schemann, Michael; Michel, Klaus; Peters, Saskia; Bischoff, Stephan C.; Neunlist, Michel

doi: 10.1152/ajpgi.00043.2002pmid: 12016115

Abstract Monitoring membrane potentials by multisite optical recording techniques using voltage-sensitive dyes is ideal for direct analysis of network signaling. We applied this technology to monitor fast and slow excitability changes in the enteric nervous system and in hundreds of neurons simultaneously at cellular and subcellular resolution. This imaging technique presents a powerful tool to study activity patterns in enteric pathways and to assess differential activation of nerves in the gut to a number of stimuli that modulate neuronal activity directly or through synaptic mechanisms. The optical mapping made it possible to record from tissues such as human enteric nerves, which were, until now, inaccessible by other techniques. multisite optical recording voltage-sensitive dyes enteric nervous system Footnotes Present Address of M. Neunlist: INSERM U 539 Hopital Hôtel Dieu, 3ème Nord Place Alexis Ricordeau, 44035 Nantes, France. Address for reprint requests and other correspondence: M. Schemann, Dept. of Physiology, School of Veterinary Medicine, Bischofsholer Damm 15/102, D-30173 Hannover, Germany (E-mail: [email protected] ). First published February 27, 2002;10.1152/ajpgi.00043.2002 Copyright © 2002 the American Physiological Society

González, Hernán E.; Eugenín, Eliseo A.; Garcés, Gladys; Solís, Nancy; Pizarro, Margarita; Accatino, Luigi; Sáez, Juan C.

doi: 10.1152/ajpgi.00298.2001pmid: 12016124

Abstract Hepatocyte gap junction proteins, connexins (Cxs) 26 and 32, are downregulated during obstructive cholestasis (OC) and lipopolysaccharide hepatocellular cholestasis (LPS-HC). We investigated rat hepatic Cxs during ethynylestradiol hepatocellular cholestasis (EE-HC) and choledochocaval fistula (CCF) and compared them with OC and LPS-HC. Levels (immunoblotting) and cellular distribution (immunofluorescence) of Cx26, -32, and -43, as well as macrophage infiltration, were studied in livers of rats under each condition. Cx26 and -32 were reduced in LPS-HC, OC, and CCF. However, in EE-HC, Cx26 did not change and Cx32 was increased. Prominent inflammation occurred in LPS-HC, OC, and CCF, which was associated with increased levels of Cx43 in LPS-HC and OC but not CCF. No inflammation nor changes in Cx43 levels occurred during EE-HC. In cultured hepatocytes, dye coupling was reduced by tumor necrosis factor-α and interleukins-1β and -6, whereas reduction induced by LPS required coculture with Kupffer cells. Thus hepatocyte gap junctions are downregulated in forms of cholestasis associated with inflammation, and reduced intercellular communication might be induced in part by proinflammatory mediators. obstructive cholestasis hepatocellular cholestasis cytokines macrophages. Footnotes This work was partially supported by Fondo Nacional parz el Desarrolo de la Ciencia y Tecnologı́a Grants 8990008 (to J. C. Sáez) and 1000563 (to L. Accatino) and by Grants 12/96 and 2/97 for residents of the school of medicine of the Pontificia Universidad Católica de Chile (to H. González). The data in this paper are from a thesis submitted in partial fulfillment of the requirements for the Degree of Doctor in Medical Sciences (H. González) at the Pontificia Universidad Católica de Chile. Address for reprint requests and other correspondence: J. C. Sáez, Dept. de Ciencias Fisiológicas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile (E-mail [email protected] ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. First published January 16, 2002;10.1152/ajpgi.00298.2001 Copyright © 2002 the American Physiological Society

Choudhry, Mashkoor A.; Fazal, Nadeem; Goto, Masakatsu; Gamelli, Richard L.; Sayeed, Mohammed M.

doi: 10.1152/ajpgi.00235.2001pmid: 12016118

Abstract The mechanism of alcohol-mediated increased infection in burn patients remains unknown. With the use of a rat model of acute alcohol and burn injury, the present study ascertained whether acute alcohol exposure before thermal injury enhances gut bacterial translocation. On day 2 postinjury, we found a severalfold increase in gut bacterial translocation in rats receiving both alcohol and burn injury compared with the animals receiving either injury alone. Whereas there were no demonstrable changes in intestinal morphology in any group of animals, a significant increase in intestinal permeability was observed in ethanol- and burn-injured rats compared with the rats receiving either injury alone. We further examined the role of intestinal immune defense by determining the gut-associated lymphoid (Peyer's patches and mesenteric lymph nodes) T cell effector responses 2 days after alcohol and burn injury. Although there was a decrease in the proliferation and interferon-γ by gut lymphoid T cells after burn injury alone; the suppression was maximum in the group of rats receiving both alcohol and burn injuries. Furthermore, the depletion of CD3 + cells in healthy rats resulted in bacterial accumulation in mesenteric lymph nodes; such CD3 + cell depletion in alcohol- and burn-injured rats furthered the spread of bacteria to spleen and circulation. In conclusion, our data suggest that the increased intestinal permeability and a suppression of intestinal immune defense in rats receiving alcohol and burn injury may cause an increase in bacterial translocation and their spread to extraintestinal sites. T lymphocyte infection immunity bacteria inflammation shock Footnotes This study was supported by National Institutes of Health through Grant R21AA-12901–01A1 (to M. A. Choudhry), and RO1 Grants GM-42577 (to R. L. Gamelli), and GM-53235 and GM-56865 (to M. M. Sayeed). Financial support from the Dept. of Surgery, Loyola University Chicago Medical Center (to M. A. Choudhry) is acknowledged. Address for reprint requests and other correspondence: M. A. Choudhry, Burn and Shock Trauma Institute, Loyola Univ. Chicago Medical Center, 2160 South First Ave., Maywood, IL 60153 (E-mail: [email protected] ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. First published January 30, 2002;10.1152/ajpgi.00235.2001 Copyright © 2002 the American Physiological Society

Hassoun, Heitham T.; Zou, Lei; Moore, Frederick A.; Kozar, Rosemary A.; Weisbrodt, Norman W.; Kone, Bruce C.

doi: 10.1152/ajpgi.00073.2001pmid: 12016132

Abstract Mesenteric ischemia-reperfusion (I/R) injury to the intestine is a common and often devastating clinical occurrence for which there are few therapeutic options. α-Melanocyte-stimulating hormone (α-MSH) is a tridecapeptide released by the pituitary gland and immunocompetent cells that exerts anti-inflammatory actions and abrogates postischemic injury to the kidneys and brainstem of rodents. To test the hypothesis that α-MSH would afford similar protection in the postischemic small intestine, we analyzed the effects of this peptide on intestinal transit, histology, myeloperoxidase activity, and nuclear factor-κB (NF-κB) activation after 45 min of superior mesenteric artery occlusion and ≤6 h of reperfusion. Rats subjected to I/R exhibited markedly depressed intestinal transit, histological evidence of severe injury to the ileum, increased myeloperoxidase activity in ileal cytoplasmic extracts, and biphasic activation of NF-κB in ileal nuclear extracts. In contrast, rats treated with α-MSH before I/R exhibited intestinal transit and histological injury scores comparable to those of sham-operated controls. In addition, the α-MSH-treated rats demonstrated less I/R-induced activation of intestinal NF-κB and myeloperoxidase activity after prolonged (6 h) reperfusion. We conclude that α-MSH significantly limits postischemic injury to the rat small intestine. transcription factor nuclear factor-κB ileus small intestine Footnotes This work was supported by National Institute of Diabetes and Digestive and Kidney Diseases Grants R01-DK-50745 (to B. C. Kone) and National Institute of General Medical Sciences Grant P50-GM-20529 (to B. C. Kone, F. A. Moore, and N. W. Weisbrodt), and the Department of Defense “DREAMS” Project (to B. C. Kone). Address for reprint requests and other correspondence: B. C. Kone, Departments of Medicine and of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, 6431 Fannin, Suite MSB 4.138, Houston, TX 77030 (E-mail: [email protected] ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. First published March 13, 2002;10.1152/ajpgi.00073.2001 Copyright © 2002 the American Physiological Society

Lourenssen, S.; Jeromin, A.; Roder, J.; Blennerhassett, M. G.

doi: 10.1152/ajpgi.00320.2001pmid: 12016136

Abstract The calcium-binding protein neuronal calcium sensor 1 (NCS-1) is involved in modulation of neurotransmitter release in the peripheral and central nervous systems. Since intestinal inflammation impairs neurotransmitter release, we evaluated the expression of NCS-1 in the normal rat colon and in dinitrobenzene sulfonic acid (DNBS)-induced colitis. Immunocytochemistry and Western blots showed high levels of NCS-1 in the myenteric plexus and in axons in the smooth muscle layers; 23 ± 2% of myenteric neurons were NCS-1 positive, with staining restricted to the largest neurons. NCS-1-positive axons decreased to 13.3 ± 0.4% of total axons by day 2 and dropped further to 7.0 ± 0.1% by day 4 , returning to control levels by day 16 . Dual-label Western blot analysis showed that the expression of NCS-1 relative to PGP 9.5 decreased by 50% on day 4 but returned to control by day 16 . The selective loss of NCS-1 during colitis may underlie the altered neural function seen in the inflamed intestine. frequenin enteric nervous system dinitrobenzene sulfonic acid Footnotes Address for reprint requests and other correspondence: M. G. Blennerhassett, Gastrointestinal Diseases Research Unit, Queens University, Hotel Dieu Hospital, 166 Brock St., Kingston, Ontario, Canada K7L 5G2 (E-mail: [email protected] ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. First published February 20, 2002;10.1152/ajpgi.00320.2001 Copyright © 2002 the American Physiological Society

Goodwin, Bryan; Kliewer, Steven A.

doi: 10.1152/ajpgi.00044.2002pmid: 12016116

Abstract Bile acids are required for the absorption of lipids and fat-soluble vitamins. The hepatic biosynthesis of bile acids is a major pathway for the catabolism and removal of cholesterol from the body. Because of their intrinsic toxicity, bile acid synthesis, transport, and metabolism must be tightly regulated. It is now apparent that members of the nuclear receptor family of lipid-activated transcription factors are key regulators of these physiological processes. A greater understanding of these receptors should afford novel opportunities for therapeutic intervention in chronic diseases such as cholestasis and dyslipidemia. farnesoid X receptor pregnane X receptor bile acids Footnotes Address for reprint requests and other correspondence: S. A. Kliewer, Univ. of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-8594 (E-mail: [email protected] ). 10.1152/ajpgi.00044.2002 Copyright © 2002 the American Physiological Society

Pandolfino, John E.; Shi, Guoxiang; Curry, Jennifer; Joehl, Raymond J.; Brasseur, James G.; Kahrilas, Peter J.

doi: 10.1152/ajpgi.00279.2001pmid: 12016131

Abstract To quantify the effect of hiatus hernia (HH) on esophagogastric junction (EGJ) distensibility, eight normal subjects and nine gastroesophageal reflux disease (GERD) patients with HH were studied with concurrent manometry, fluoroscopy, and stepwise controlled barostatic distention of the EGJ. The minimal barostatic pressure required to open the EGJ during the interswallow period was determined. Thereafter, barium swallows were imaged in 5-mmHg increments of intrabag pressure. EGJ diameter and length were measured at each pressure during deglutitive relaxation. The EGJ opening diameter was greater in hernia patients compared with normal subjects during deglutitive relaxation at all pressures, and EGJ length was 23% shorter. EGJ opening pressure among hernia patients was lower than normal subjects during the interswallow period. In conclusion, the EGJ of GERD patients with HH was more distensible and shorter than normal subjects. These findings partially explain why HH patients are predisposed to reflux by mechanisms other than transient lower esophageal sphincter relaxations, sustain greater volumes of refluxate, and have a reduced ability to discriminate gas from liquid reflux. hiatus hernia gastroesophageal reflux disease Footnotes Address for reprint requests and other correspondence: P. J. Kahrilas, Northwestern University Medical School, Division of Gastroenterology & Hepatology, Dept. of Medicine, Searle Bldg., 10th Floor, Suite 541, 303 East Chicago Ave., Chicago, IL 60611-3008 (E-mail: [email protected] ). The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “ advertisement ” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. 10.1152/ajpgi.00279.2001 Copyright © 2002 the American Physiological Society