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Kupffer Cell Aggregation and Perivenular Distribution in Steatohepatitis Jay H

Kupffer Cell Aggregation and Perivenular Distribution in Steatohepatitis Jay H

Kupffer Cell Aggregation and Perivenular Distribution in Jay H. Lefkowitch, M.D., Jennifer H. Haythe, M.D., Nicole Regent, M.D. Departments of Pathology (JHL) and Medicine (JHH), College of Physicians and Surgeons, Columbia University; and Department of Psychiatry (NR), The New York Hospital—Weill Medical Center, New York, New York

KEY WORDS: Fatty , Kupffer cells, Liver , release from inflammatory cells, en- Liver pathology, Steatohepatitis. dotoxin, peroxidation, and generation of Mod Pathol 2002;15(7):699–704 reactive oxygen species are among the factors currently thought to be important in the patho- Steatohepatitis (SH) has received exceptional atten- genesis of alcoholic and nonalcoholic steato- tion in clinical and research during the (SH). To more fully evaluate the role of past decade because of the wide prevalence of al- mononuclear inflammatory cells in SH, 11 nee- cohol use, obesity, and diabetes (1, 2). The patho- dle liver showing SH were selected for genesis of SH is related to the oxidative stress and immunohistochemical staining to analyze the lipid peroxidation associated with the fatty liver (3), type and distribution of mononuclear inflam- endotoxemia (4), activation of hepatic stellate cells, matory cells, including T and B and a complex cytokine network in which produc- and Kupffer cells (using immunostains for CD3, tion of (TNF)-␣ is prominent CD4, CD8; CD20; and CD68, respectively). An (5–7). Although classic morphologic studies of alco- additional seven biopsies showing normal or holic steatohepatitis (ASH; 8–10) and, more re- fatty liver were also selected for CD68 immuno- cently, of nonalcoholic steatohepatitis (NASH; 11– staining. Immunohistochemistry showed mild 13) have demonstrated the prominence of -to moderate (1؉ to 2؉) numbers of T cells, with neutrophilic leukocytes within the centrilobular le equal representation of CD4 and CD8 cells. T sion of steatohepatitis ( ballooning, fatty cells were found in portal tracts and in regions change, Mallory bodies, and pericellular/perisinu- of SH. B cells were only rarely present. CD68 soidal ), current hypotheses concerning the staining of simple fatty liver and normal liver pathogenesis of SH indicate major roles for lym- showed elongated, spindle-shaped Kupffer cells phocytes and (Kupffer cells). diffusely distributed along the sinusoids In this study, immunohistochemical stains of 11 throughout the lobules. In contrast, in cases of needle liver biopsies showing steatohepatitis were SH, there was prominent enlargement and ag- used to demonstrate T cells (including CD4 and gregation of Kupffer cells in perivenular re- CD8 cells), B cells, and Kupffer cells. The type and gions. Scattered large vacuoles of that had distribution of these mononuclear cells were eval- appeared to be within on routine uated with regard to current data concerning the stain were found actually to be within Kupffer pathogenesis of SH. cells. These results support the concept that hepatic Kupffer cells are a major immune effec- MATERIALS AND METHODS tor cell in the pathogenesis of steatohepatitis. A potential direct role in hepatic lipid The files of the Division of Surgical Pathology of processing is also postulated. the Department of Pathology, Columbia- Presbyterian Medical Center, were searched for liver biopsies with a diagnosis of SH from 1990 to Copyright © 2002 by The and Canadian Academy of 2001. Eleven cases (needle biopsies) were selected, Pathology, Inc. VOL. 15, NO. 7, P. 699, 2002 Printed in the U.S.A. and the medical records of the respective patients Date of acceptance: April 11, 2002. were reviewed for history of use, obesity, Address reprint requests to: Jay H. Lefkowitch, M.D., Department of Pathology, College of Physicians and Surgeons, 630 West 168th Street, diabetes or other putative etiologic factors. Seven New York, NY 10032; e-mail: [email protected]; fax: 212-305-5498. control cases were also selected for CD68 (Kupffer DOI: 10.1097/01.MP.0000019579.30842.96 cell) immunohistochemical staining once the CD68

699 FIGURE 1. CD68 immunostaining of Kupffer cells in a case of mild steatohepatitis. A, low magnification shows prominent aggregated Kupffer cells near the central (arrows; magnification, 50ϫ). B, a portion of A shows a portal tract (P) and aggregated prominent Kupffer cells near the central (arrow). Individual elongated Kupffer cells in the midzonal and periportal regions are less conspicuous (magnification, 125ϫ). C, aggregated Kupffer cells with enlarged, rounded cell bodies and intracytoplasmic granules are present near mildly ballooned hepatocytes and the central vein (V; magnification, 325ϫ).

700 Modern Pathology their specific location, including perivenular (V), within portal tracts (P), within lobular sinusoids (L), and within fibrous septa (SE).

RESULTS

Immune cells in Steatohepatitis Cases T and B cells CD3-positive T cells were found in mild to mod- erate numbers within portal tracts and fibrous septa and in regions of perivenular steatohepatitis. The T cells were composed of an equal admixture of CD4- and CD8-positive cells. B cells were only rarely identified at any site.

Kupffer cells Aggregates of prominent CD68-positive Kupffer cells were present in perivenular regions of SH, readily seen even at low magnification (Fig. 1A-C). At these sites they were characterized by enlarged and rounded cell bodies containing numerous densely stained intracellular granules (positive ly- sosomal staining). Elsewhere, along sinusoids in the midzonal and periportal regions, Kupffer cells were nonaggregated, individual cells with elongated ta- pering cell bodies identical to the appearance of CD68-stained Kupffer cells in control sections of normal liver (Fig. 2).

FIGURE 2. CD68 immunostaining of normal control liver shows individual elongated Kupffer cells diffusely within the sinusoids. (V ϭ central vein; magnification, 125ϫ.) Inset, individual, elongated, tapering Kupffer cells are present within sinusoids (magnification, 325ϫ). TABLE 1. Grading and Distribution of Immune Cells in Steatohepatitis

a ASH/NASH Distribution Case Sex Age (y) b staining results for SH cases were apparent. These (Risk) CD3 CD20 CD68 included three normal liver biopsies, two with mild 1 F 31 NASH 2ϩ (V) R (V) Agg (V) or moderate fat, and two with marked fat. (Ob) 2ϩ (P) Immunohistochemical staining was performed 2 M 51 NASH 1ϩ (V) R (V) Agg (V) (Ob) 1ϩ (P) on deparaffinized sections from paraffin- 3 M 63 NASH 3ϩ (V) R (P) Agg (V) embedded, formalin-fixed needle spec- (Ob)a 3ϩ (P) imens using the DAKO EnVision™ ϩ System, Per- 4 F 55 NASH 2ϩ (V) R (V) Agg (V) (Ob) 1ϩ (P) oxidase (3,3'-diaminobenzidine), a two-step 5 F 39 ASH 1ϩ (V) O Agg (V) immunohistochemical technique using an avidin R (P) and biotin-free horseradish peroxidase–labeled 6 M 51 NASH 1ϩ (V) R (P) Agg (V) (D) 2ϩ (P) polymer conjugated with secondary to 7 F 59 ASH 2ϩ (V) R (V) Agg (V) bind to the primary . The primary mouse 2ϩ (P) monoclonal antibodies used included CD3 (T cells), 8 F 35 ASH 2ϩ (L) O Agg (V) 2ϩ (SE) CD8 (T cytotoxic/suppressor cells), CD20 (B cells), 9 M 64 ASH 1ϩ (L) 1ϩ (SE) Agg (V) and CD68 (Kupffer cells/macrophages) from DAKO 2ϩ (SE) (Carpinteria, CA) and CD4 (T helper/inducer cells) 10 F 76 NASH 2ϩ (V) R (P ϩ V) Agg (V) (Ob) 1ϩ (P) from Novocastra, distributed by Vector (Burlin- 11 M 71 ASH 2ϩ (V) 1ϩ (V) Agg (V) game, CA). 3ϩ (P) 1ϩ (P) Immunohistochemical staining results were re- ASH, alcoholic steatohepatitis; NASH, nonalcoholic steatohepatitis. viewed, and the numbers of respective positively a Lobular distribution of immune cells includes V (perivenular), P stained immune cells were graded as follows: 0 (portal tract), L (lobular sinusoids), and SE (within fibrous septa). Agg, ϩ ϩ aggregates. (none); R (rare cells present); 1 (few); 2 (mod- b NASH risk factors include obesity (Ob) and diabetes (D). erate numbers); 3 (many). Notation was made of c Case 3 was also virus positive.

Kupffer Cells in Steatohepatitis (J.H. Lefkowitch et al.) 701 One case of NASH (Case 4) was sectioned serially seen in cases of SH. Kupffer cells in the fatty and stained alternately with hematoxylin and eosin were occasionally enlarged (Fig. 4B) and rarely con- (H&E) and CD68 immunostaining to closely com- tained lipid vacuoles. pare the routine light-microscopic appearances with the corresponding adjacent immunostain re- DISCUSSION sults (Fig. 3A and B). This case showed aggregated and enlarged Kupffer cells in sinusoids directly sur- Although classic morphologic studies have long rounding hepatocytes with severe hydropic swell- emphasized infiltration of in the he- ing and Mallory bodies. Inspection of the H&E sec- patic lesion of (8, 10), more re- tion disclosed the relative inconspicuousness of the cent investigations of the pathogenesis of SH in Kupffer cells in these foci as well as the potential for alcoholic and nonalcoholic individuals have dem- misidentifying them as lymphocytes or endothelial onstrated the presence of a complex cytokine net- cells. In addition, these sections demonstrated that work in which Kupffer cells and lymphocytes play some of the large lipid vacuoles that appeared to be important roles (5, 14). Among the in- ␣ ␣ within hepatocytes on routine H&E were within volved in SH, generation of TNF- and TNF- – Kupffer cells (Fig. 3B). This was also found in other inducible cytokines such as interleukin-1, -6, and -8 SH cases and in the control fatty livers (see below). were stressed in a recent overview of the topic by Tilg and Diehl (5). The significance of TNF-␣ acti- vation of nuclear factor-kappa B in in CD68 Immunostaining of Normal and Fatty Liver alcoholics and the subsequent transcription of The normal liver showed a diffuse sinusoidal dis- -related genes have also been the sub- tribution of elongated individual Kupffer cells (Fig. ject of recent studies (15, 16). 2). This pattern was maintained in the fatty livers Our study reconfirms earlier work that immuno- (Fig. 4A and B), without the perivenular aggregation histochemically demonstrated T cells in the livers of

FIGURE 3. A and B are consecutive serial sections from a case of severe NASH. A, the centrilobular region at center right shows markedly ballooned hepatocytes, many of which contain Mallory bodies (short arrows). Sinusoidal inflammation at Points 1, 2, and 3 correspond in B to prominent aggregates of Kupffer cells. A large lipid droplet at top appears to be within a hepatocyte (open arrow). Hematoxylin and eosin stain, 325ϫ. B, CD68-immunostained serial section demonstrates Kupffer cells aggregates within sinusoids. A large vacuole of lipid at top is enclosed within a Kupffer cell (open arrow; specific immunoperoxidase; magnification, 325ϫ.)

702 Modern Pathology FIGURE 4. Mild (A) and marked (B) fatty liver with CD68 immunostaining for Kupffer cells. A diffuse sinusoidal distribution of individual Kupffer cells is present, without perivenular aggregation. V ϭ central vein. An enlarged Kupffer cell is seen near the bottom in B. (Magnification, A and B, 125ϫ.) individuals with alcoholic liver (14). A com- also demonstrated clusters of Kupffer cells with parative light-microscopic study of ASH and NASH CD68 immunostaining. also recorded the presence of 1ϩ portal inflamma- The finding of lipid vacuoles in some Kupffer tion in 49 and 57% of cases, respectively (12), cells suggests that these cells may be processing whereas another study of NASH found 21 of 49 lipid or phagocytosing effete fatty hepatocytes. Ly- cases to have predominance of perivenular mono- sosomal activity in these Kupffer cells could repre- nuclear cells (13). In our study, portal tract and sent one mechanism by which reactive oxygen spe- sinusoidal T cells were generally mild to moderate cies are generated in the fatty liver. in number. B cells were rarely identified, as also The localization of Kupffer cells to perivenular shown in the study of Chedid et al. (14). regions of steatohepatitis is consonant with the cur- The most distinctive finding in our study was rent view that the pathogenesis of this condition is the presence of aggregates of enlarged Kupffer related to intrahepatic release of TNF-␣ by Kupffer cells in perivenular regions of steatohepatitis, as cells, with subsequent generation of cytokines such compared with the diffuse, panlobular sinusoidal as interleukin-1, interleukin-6, interleukin-8 and distribution seen in the normal or fatty liver with- transforming growth factor-␤ (5). Induction of out SH. On routine light microscopy, these CD14 receptors on Kupffer cells by ethanol or by Kupffer cells may be relatively inapparent or mis- of endotoxin appears to be a taken for lymphocytes or endothelial cells. The critical event preceding the cytokine cascade and presence of Kupffer cells among the constituent production of reactive oxygen species by Kupffer inflammatory infiltrates of SH was not assessed in cells (6, 7). Future immunohistochemical studies to several classic pathologic studies of alcoholic evaluate expression of CD14 receptors on Kupffer hepatitis (8–10) but was cited in a recent ultra- cells in SH would provide additional support for structural and immunohistochemical investiga- this concept. tion of stellate and Kupffer cells in 35 patients In summary, this study demonstrated the pres- with alcoholic (17). The latter study ence of T cells and Kupffer cells as constituents of

Kupffer Cells in Steatohepatitis (J.H. Lefkowitch et al.) 703 the inflammatory lesion of ASH and NASH, with 6. Järveläinen HA, Fang C, Ingelman-Sundberg M, Lindros KO. unusual prominence of enlarged and aggregated Effect of chronic coadministration of endotoxin and ethanol Kupffer cells present in perivenular regions of ste- on liver pathology and proinflammatory and anti- inflammatory cytokines. Hepatology 1999;29:1503–10. atohepatitis. No significant differences between 7. Järveläinen HA, Fang C, Ingelman-Sundberg M, Lukkari TA, steatohepatitis of alcoholic versus nonalcoholic Sippel H, Lindros KO. Kupffer cell inactivation alleviates type were detected in the numbers or distribution ethanol-induced steatosis and CYP2E1 induction but not of these inflammatory cells. Although previous his- inflammatory responses in rat liver. J Hepatol 2000;32:900– topathological criteria for the diagnosis of steato- 10. hepatitis have stressed the presence of 8. Mallory FB. of the liver. Five different types of lesions from which it may arise. Bull Johns Hopkins Hosp infiltrates, a contemporary comprehensive mor- 1911;22:69–74. phologic definition of this lesion should provide a 9. French SW, Nash J, Shitabata P, et al. Pathology of alcoholic more inclusive approach to the spectrum of inflam- liver disease. Semin Liver Dis 1993;13:154–69. mation seen, with particular recognition of the par- 10. Baptista A, Bianchi L, De Groote J, et al. : ticipation of Kupffer cells. morphological manifestations. Lancet 1981;1:707–11. 11. Ludwig J, Viggiano TR, McGill DB, Oh BJ. Nonalcoholic steatohepatitis: experiences with a hitherto un- Acknowledgments: The authors thank Dianne named disease. Mayo Clin Proc 1980;55:434–8. Alexis and Ritchie Alsberry for immunohistochemi- 12. Diehl AM, Goodman Z, Ishak KG. Alcohollike liver disease cal staining and Alfred Lamme for photography. in nonalcoholics. A clinical and histologic comparison with alcohol-induced . 1988;95:1056– 62. REFERENCES 13. Lee RG. Nonalcoholic steatohepatitis: a study of 49 patients. Hum Pathol 1989;20:594–8. 1. Maher J. The CYP2E1 knockout delivers another punch: first 14. Chedid A, Mendenhall CL, Moritz TE, et al. Cell-mediated ASH, now NASH. Hepatology 2001;33:311–2. hepatic injury in alcoholic liver disease. Gastroenterology 2. Sheth SG, Gordon FD, Chopra S. Nonalcoholic steatohepa- 1993;105:254–66. titis. Annu Intern Med 1997;126:137–45. 3. James OFW, Day CP. Non-alcoholic steatohepatitis (NASH): 15. Szabo G. New insights into the molecular mechanisms of a disease of emerging identity and importance. J Hepatol alcoholic hepatitis: a potential role for NF-KB activation? 1998;29:495–501. J Lab Clin Med 2000;135:367–9. 4. Enomoto N, Ikejima K, Bradford B, et al. Alcohol causes both 16. Hill DB, Barve S, Joshi-Barve S, McClain C. Increased mono- tolerance and sensitization of rat Kupffer cells via mecha- cyte nuclear factor-KB activation and tumor necrosis factor nisms dependent on endotoxin. Gastroenterology 1998;115: production in alcoholic hepatitis. J Lab Clin Med 2000;135: 443–51. 387–95. 5. Tilg H, Diehl AM. Cytokines in alcoholic and nonalcoholic 17. Cameron RG, Neuman MG. Novel morphologic findings in steatohepatitis. N Engl J Med 2000;343:1467–76. alcoholic liver disease. Clin Biochem 1999;32:579–84.

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