A regulatory circuit controlled by extranuclear and nuclear retinoic acid receptor α determines T cell activation and function

Ligation of retinoic acid receptor alpha (RARα) by RA promotes varied transcriptional programs associated with immune activation and tolerance, but genetic deletion approaches suggest the impact of RARα on TCR signaling. Here, we examined whether RARα would exert roles beyond transcriptional regulation. Specific deletion of the nuclear isoform of RARα revealed an RARα isoform in the cytoplasm of T cells. Extranuclear RARα was rapidly phosphorylated upon TCR stimulation and recruited to the TCR signalosome. RA interfered with extranuclear RARα signaling, causing suboptimal TCR activation while enhancing FOXP3+ regulatory T cell conversion. TCR activation induced the expression of CRABP2, which translocates RA to the nucleus. Deletion of Crabp2 led to increased RA in the cytoplasm and interfered with signalosome-RARα, resulting in impaired anti-pathogen immunity and suppressed autoimmune disease. Our findings underscore the significance of subcellular RA/RARα signaling in T cells and identify extranuclear RARα as a component of the TCR signalosome and a determinant of immune responses.

Small Intestine Epithelial CD4 Cytotoxic T Lymphocytes Provide Innate-Like Protection against Enteric Pathogens without Risk of Immunopathology

CD4 T helper (Th) cells reprogram to cytotoxic T lymphocytes (CTLs) in the small intestinal epithelium. In the present study, CD4 CTLs were evaluated for their potential to promote tolerance during steady state as well as their ability to fend off enteric pathogens during infection.

The CD4 T cell adoptive transfer model of colitis was used to determine if CTLs can promote tolerance. Naïve CD4 T cells were differentiated towards a CTL, Treg, or inflammatory Th (Th1 or Th17) fate and transferred into RagKO recipients. Strikingly, the recipients that received CTLs, like the Treg condition, had minimal disease; in contrast, the Th conditions all exhibited pathology. To determine if the forced presence of Th cells exacerbates colitis disease, CD4 T cell adoptive transfers were performed using cells that were forced to stay Th or predisposed to becoming CTLs. Altogether, the conversion of Th to CTL mitigated disease pathology and promoted tolerogenic conditions.

The protective role of CD4 CTLs to rapidly respond to enteric pathogens and contain infections was also examined. Using Salmonella as a bacterial model, the data show that pre-existing CD4 CTLs have the capacity to kill infected cells, thereby preserving the integrity of the barrier and preventing bacterial dissemination. Functionally, CD4 CTLs represent a strategy of protective tolerance by the immune system to fortify the epithelium with quiescent but primed CTLs that can provide rapid immunity during enteric infection.

Supported by grants from the NIH (U01 AI125957, F31 DK124078)

12α-Hydroxylated bile acid enhances accumulation of adiponectin and immunoglobulin A in the rat ileum

We previously reported that dietary supplementation with cholic acid (CA), the primary 12α-hydroxylated (12αOH) bile acid (BA), reduces plasma adiponectin concentration in rats. The aim of this study was to examine the distribution of adiponectin in the body of CA-fed rats and its influence on mucosal immunoglobulin A concentration in the intestine. Rats were fed a diet supplemented with or without CA (0.5 g CA/kg diet) for 13 weeks. A reduction in plasma adiponectin level was observed from week 3. At the end of the experiment, the CA diet reduced plasma adiponectin concentration both in the portal and aortic plasma. Accumulation of adiponectin was accompanied by an increase in cadherin-13 mRNA expression in the ileal mucosa of CA-fed rats. No increase was observed in adiponectin mRNA expression in the ileal and adipose tissues of the CA-fed rats. Immunoglobulin A concentration in the ileal mucosa was elevated in the CA-fed rats and was correlated with the ileal adiponectin concentration. 12αOH BAs may modulate mucosal immune response that are involved in the accumulation of adiponectin in the ileum.

Dietary Antigens Drive Protective Innate-like CD4 T Cell Immunity at the Mucosal Barrier of the Small Intestine

CD4 T helper (Th) cells reprogram to cytotoxic T lymphocytes (CTLs) in the intestinal epithelium during steady state. The unique localization of mucosal CD4 CTLs, in the absence of a pathogenic threat, suggests local non-pathogen antigens and organ-specific properties direct the CTL conversion.

Similar to myeloid antigen presenting cells, intestinal epithelial cells (IECs) constitutively express MHC class II (MHCII), indicating crosstalk with nearby CD4 T cells. IECs constantly absorb and process luminal digested proteins and present these dietary antigens to neighboring CD4 T cells on their basolateral side. We have generated solid evidence with murine conditional knock-out and bone marrow chimera models that MHCII+ IECs and the dietary epitopes they present are instrumental in the development of small intestinal CD4 CTLs in a homeostatic, non-inflammatory environment.

These dietary antigen-specific CD4 CTLs accumulate over time as innate-like protective cells that fortify the epithelium with a pre-existing protective arm. As fully differentiated and functional resident T cells, CD4 CTLs are aptly designed to rapidly respond, independent of pathogen specificity, and contain infections. Using Salmonella as an enteric pathogen model, the data show that dietary antigen-specific CD4 CTLs have the capacity to rapidly and effectively kill infected epithelial cells, thereby preserving the integrity of the barrier and blocking systemic spreading of the pathogen. The double-pronged ability for CD4 CTLs to protect against invaders while also mitigating immunopathology, by differentiating inflammatory CD4 T cells into excellently trained CD4 CTLs, reveal previously unknown mechanisms of mucosal lymphocyte biology.

Correlation between 12α-hydroxylated bile acids and insulin secretion during glucose tolerance tests in rats fed a high-fat and high-sucrose diet

Background

Previously, we found a significant relationship in a rat study between energy intake and bile acid (BA) metabolism especially 12α-hydroxylated (12αOH) BAs. The present study was designed to reveal relationships among BA metabolism, glucose tolerance, and cecal organic acids in rats fed a high-fat and high-sucrose diet (HFS) by using multivariate and multiple regression analyses in two types of glucose tolerance tests (GTTs).

Methods

Male WKAH/HkmSlc rats were fed with a control or a HFS for 13 weeks. Oral glucose tolerance test (OGTT) and intraperitoneal glucose tolerance test (IPGTT) were performed at week 9 and 11, respectively. BAs were analyzed by using ultra high-performance liquid chromatography-mass spectrometry. Organic acid concentrations in cecal contents were analyzed by using ultra high-performance liquid chromatography with post-column pH buffered electric conductivity method.

Results

A positive correlation of aortic 12αOH BA concentration was observed with energy intake and visceral adipose tissue weight. We found that an increase of 12αOH BAs in enterohepatic circulation, intestinal contents and feces in the HFS-fed rats compared to those in control rats regardless of no significant increase of total BA concentration in the feces in the test period. Fecal 12αOH BA concentration was positively correlated with maximal insulin level in OGTT and area under curve of insulin in IPGTT. There was a positive correlation between aortic 12αOH BAs concentration and changes in plasma glucose level in both OGTT and IPGTT. In contrast, a decrease in the concentration of organic acids was observed in the cecal contents of the HFS-fed rats. Multiple linear regression analysis in the IPGTT revealed that the concentrations of aortic 12αOH BA and cecal acetic acid were the predictors of insulin secretion. Moreover, there was a positive correlation between concentration of portal 12αOH BAs and change in insulin concentration of peripheral blood in the IPGTT.

Conclusion

The distribution analysis of BA compositions accompanied by GTTs revealed a close relationship between 12αOH BA metabolism and insulin secretion in GTTs in rats.

Alteration of Bile Acid Metabolism by a High-Fat Diet Is Associated with Plasma Transaminase Activities and Glucose Intolerance in Rats

Ingestion of a high-fat (HF) diet is known to enhance bile acid (BA) secretion, but precise information about the BA molecular species is lacking, especially information on the conjugated BAs in enterohepatic circulation. As cholesterol is the precursor of BAs, we analyzed alterations of the entire BA metabolic pathway in response to a HF diet without the addition of cholesterol and BA in the diet. Additionally, we evaluated the relationships between BA metabolism and some disorders, such as plasma transaminase activities and glucose intolerance induced by the HF diet. Acclimated WKAH/HkmSlc male rats (3 wk old) were divided into two groups fed a control or the HF diet for 22 wk. Fasting blood glucose was measured during the experimental period, and an intraperitoneal glucose tolerance test was performed at week 21. As a result, ingestion of the HF diet selectively increased the concentration of taurocholic acid in the bile and small intestinal contents as well as deoxycholic acid in the large intestinal contents and feces. These results indicated a selective increase of 12α-hydroxylated BA concentrations in response to the HF diet. Moreover, fecal 12α-hydroxylated BA concentration was positively correlated with cumulative energy intake, visceral adipose tissue weight, and glucose intolerance. The present study suggests that fecal 12α-hydroxylated BA is a non-invasive marker that can detect the early phase of glucose intolerance.

TCR signal strength shapes functional imprinting during CD4 T cell development

Naïve CD4 and CD8ab T cells are selected in the thymus in response to low-avidity TCR interactions. Such weak TCR signals install a quiescent program that guides naïve T cells to the lymph nodes where they differentiate upon encounter of cognate antigen. Thymocytes expressing self-specific TCRs can be agonist-selected in response to a strong TCR signal and differentiate in the thymus to functionally committed double negative T cells, NKT cells or regulatory T cells. Although the role for strength of TCR activation is clear in instructing these different outcomes, the impact of self-recognition in the thymus on “naïve” T cells is unclear. Previous work demonstrated that negative selection of self-specific T cells is not all encompassing and that affinity for self could even enhance immune protection against pathogens.

We have used Stim1fl/fl Stim2fl/fl conditional deletion mice that fail to sustain calcium entry into the cytosol upon TCR activation to assess the role of TCR strength during selection. We confirmed that agonist selection is drastically affected in these mice whereas numbers of conventional T cells are not. Interestingly, viSNE representation of multi-parameter flow cytometry revealed single cell heterogeneity among the CD4SP thymocyte subset that is controlled by Stim1/Stim2. This indicates that differential TCR activation levels give rise to phenotypically different CD4 T cells. Purification of a strongly signaled (Stim1/2-dependent) subset of CD4 thymocytes showed functional differences in terms of their ability to proliferate in response to TCR activation. Our work points to a role for self-recognition during T cell selection that shapes the response of individual CD4 T cells to TCR activation in the periphery.

CD160-HVEM signaling in intestinal epithelial cells modulates gut microbial homeostasis

Intestinal epithelial cells (IEC) are a first barrier that segregates host and commensal bacteria to maintain intestinal homeostasis. Intestinal intraepithelial lymphocytes (IEL) are located beneath or between adjacent IEC and directly contact IEC. The herpes virus entry mediator (HVEM), a member of the tumor necrosis factor receptor superfamily (TNFRSF), is highly expressed by IEC. Epithelial HVEM expression was previously reported as a regulator of innate immune defense during acute infections in the intestine (Shui et al., Nature, 2012). Here, we identify that HVEM signaling in IEC is important for the regulation of the gut microbiota at steady state. Mice with an epithelial-specific deletion of the gene encoding HVEM (HvemΔIEC) had significantly increased segmented filamentous bacteria (SFB) which caused an increase in Th17 cells in the ileum. Treatment with the antibiotic vancomycin eliminated SFB and decreased Th17 cells in HvemΔIEC mice. Additionally, mice with a deletion of the gene encoding CD160, which is a ligand for HVEM and is highly expressed by IEL, including intraepithelial innate lymphoid cells (ILC) and intraepithelial T cells, had increased SFB in the ileum. Our findings suggest that the interaction of CD160 expressed by IEL with HVEM expressed by IEC is important at steady state for shaping the microbiota in the intestine.

The Cd8 locus Controls the Functional Conversion of CD4 Th cells to CD4 CTL in the Intestine

CD4 T cells adapt to their surroundings by differentiating into various T helper (Th) subsets. At steady state, regulatory CD4 T cells (Treg) and interleukin (IL)-17 producing CD4 T cells (Th17 cells) are present in the intestine and localize mainly to the lamina propria, whereas CD4 cytotoxic T lymphocytes (CTL) reside in the epithelium. A hallmark of CD4 CTL is the reactivation of the Cd8 locus and the re-expression of CD8a controlled by the Cd8 enhancer I (E8I). We showed before that CD4 Th cells can reprogram to CTL. Here, we elucidated a mechanism that drives the CTL reprogramming of CD4 Th cells. We identified a long noncoding RNA transcribed from the Cd8 locus, as the critical regulator of the reciprocal expression of T-BET and RUNX combined with the suppression of Foxp3 and Rorc in CD4 CTL precursors. We further found that the E8I region functions as is central coordinator of the RUNX3-controlled cytotoxic gene expression program marked by the re-expression of CD8a. Adoptive transfer of naïve E8I deletion mutant CD4 T cells to Rag1−/− recipient mice led to accelerated weight loss, and severe small and large intestine inflammation with excessive accumulation of pathogenic IL-17A and IL-17A/IFNg double producing CD4 T cells. Altogether, these findings indicate that the Cd8 locus controls the functional polarization of CD4 Th cells and furthermore, that the conversion to CTL not only enhances the direct protective capacity but also regulate the immune response and prevents excessive inflammation and immune pathology at the mucosal border of the intestine.

Small Intestinal Cytotoxic CD4 T Cells: Novel Mechanisms of Development and Unique Protective Capability

Conventional CD4 T helper T cells convert to CD4 cytotoxic T lymphocytes (CTL) in the small intestinal epithelium during steady state, but the mechanism and antigens that drive their generation and purpose(s) at this barrier are largely unknown. The unique localization of mucosal CD4 CTL to the small intestinal epithelium suggests local non-pathogen antigens and organ-specific properties that direct CD4 CTL to develop from CD4 T helper (Th) cells.

Similar to traditional antigen presenting cells (APCs), intestinal epithelial cells (IECs) express MHC class II (MHCII), indicating a possible influence over nearby CD4 T cells. In addition, IECs are constantly processing luminal contents and therefore are likely to present non-pathogen-derived antigens (e.g. diet or commensal bacteria-derived) to CD4 T cells at its baso-lateral side. Taken together, we hypothesized and now show that the constant presentation of dietary antigens by IECs in a non-inflammatory environment leads to the development of CD4 CTL in the small intestinal epithelium.

These CD4 CTL accumulate over time and fortify the small intestine as an innate-like defensive arm specifically designed to contain infections while minimizing inflammation at this delicate interface. Many types of immune cells are involved in combating Salmonella infection, but CD4 CTL represent a distinct niche. Here, we demonstrate the protective capacity of CD4 CTL to rapidly and effectively kill infected epithelial cells thereby preventing systemic spread of pathogens as well as excessive immune pathology caused by infiltrating peripheral adaptive immune cells.

Natural ThPOK− CD4 cytotoxic T lymphocytes : Thymic development of a new distinct self-specific CD4 T cell population

The lineage commitment to either CD4 or CD8 T cells is made in the thymus, where thymocytes with specificity for MHC-II molecules differentiates into the CD4 “helper” linage whereas ones specific for MHC-I molecules commit to the CD8 “cytotoxic” lineage. The molecular regulation is controlled by the action of key transcription factors. Notably ThPOK, which promotes the CD4 fate and suppress the cytotoxic fate of CD4 T cells. Recently, we made a major breakthrough and showed that these lineages is not fixed and the mature peripheral CD4 T cells have the plasticity to lose ThPOK expression and reprogram to ThPOKneg CD4 CTL (cytotoxic T lymphocytes) marked by the expression of CD8a, Granzyme B and potent killer capacity.

Investigating the origin of CD4 CTL, we observed in ThPOK fate maping mouse a strong proportion of CD4 CTL that never expressed ThPOK, suggesting that some CD4 CTL are natural cytotoxic cells that develop in the thymus. Based on a recent works allowing the analysis of mature CD4 cells in the thymus, we observed a substantial number of mature CD4 T cells that do not express ThPOK and display an active-like phenotype. Moreover, once injected, thymic ThPOKneg mature CD4 T cells remain ThPOKneg in the periphery and start to acquire CD8a expression demonstrating that natural CD4 CTL arise from the thymus. We also demonstrated that this population requires a strong TCR signal during their development, suggesting that natural CD4 CTL have a repertoire specific for self-antigens.

We have identified a new distinct population of mature CD4 T cells that develop in the thymus: the natural cytotoxic CD4 T lymphocytes. We also established mechanism underlying these process by demonstrating that CD4 CTL needs a strong TCR signal for their differentiation.

Zinc directly stimulates cholecystokinin secretion from enteroendocrine cells and reduces gastric emptying in rats

Zinc, an essential mineral element, regulates various physiological functions such as immune responses and hormone secretion. Cholecystokinin (CCK), a gut hormone, has a role in protective immunity through the regulation of gastrointestinal motility, appetite, and inflammatory response. Here, we examined the effect of zinc on CCK secretion in STC-1 cells, an enteroendocrine cell line derived from murine duodenum, and in rats. Extracellular zinc triggered CCK secretion accompanied with increased intracellular Ca(2+) and Zn(2+) mobilization in STC-1 cells. Zinc-induced CCK secretion was abolished in the absence of intracellular Zn(2+) or extracellular calcium. Upon inhibition of transient receptor potential ankyrin 1 (TRPA1), extracellular zinc failed to increase intracellular Ca(2+) and subsequent CCK secretion. In rats, oral zinc administration decreased gastric emptying through the activation of CCK signaling. These results suggest that zinc is a novel stimulant for CCK secretion through the activation of TRPA1 related to intracellular Zn(2+) and Ca(2+) mobilization.

Peripheral Reprogrammed CD4+ CTL Efficiently Control Tumor Growth

The initial commitment to either the CTL- or Th-lineage is made during thymic development, where thymocytes expressing an MHC class II–reactive TCR commit to the CD4 helper T cell lineage, whereas thymocytes with specificity for MHC class I differentiate into the CD8 CTL lineage. The molecular regulation is controlled by the action and counteraction of transcription factors, such as t ThPOK, which promotes the Th fate and Runx3 which drives the differentiation of MHC class I restricted thymocytes into the CD8 CTL-lineage. This dichotomy persists in the periphery, where ThPOK continues to suppress the cytotoxic fate of MHC class II–restricted CD4+ Th cells. Recently, our team made a major breakthrough and showed that the thymic lineage commitment of CD4 Th cells is not fixed and that mature peripheral CD4+ T cells have the plasticity to lose ThPOK expression.

We demonstrated that the loss of Thpok expression and the Th fate coincides with the re-expression of CD8α and the induction of a typical CTL phenotype, including 2B4 and Granzyme B expression and IFN-γ and TNF-α cytokine production. Using an in vitro cytotoxic assay, our lab found that these reprogrammed ThPOK− CD4+ T cells display killer capacities.

In a new study we now investigate the role of CD4 CTL in anti-tumor immune surveillance. Using the well-described B16-melanoma tumor model, we demonstrated that in vitro differentiated OVA-specific CD4 CTL display anti-tumor capacity and efficiently killed OVA-expressing B16 tumor cells.

This studies on CD4 CTL in the cancer field will not only greatly expand our basic understanding of anti-tumor immunity but it will undoubtedly have major implications for translational research to design new cell therapies to treat devastating cancers.

Deoxycholic acid is involved in the proliferation and migration of vascular smooth muscle cells

Obesity is increasingly becoming associated with increased risk of atherosclerosis. Serum levels of the bile acid deoxycholic acid (DCA) are elevated in mice with obesity induced by a high-fat (HF) diet. Therefore, we investigated the influence of DCA on the functions of vascular smooth muscle cells (VSMCs) because the initiation and progression of atherosclerosis are associated with VSMC proliferation and migration. DCA induced c-jun N-terminal kinase (JNK) activation whereas a JNK inhibitor prevented DCA-induced VSMC proliferation and migration. Based on these findings, we examined whether DCA promotes the expression of platelet-derived growth factor β-receptor (PDGFRβ) that has a c-Jun binding site in its promoter region. The mRNA and protein expression levels of PDGFRβ were upregulated in VSMCs after a 24- and 48-h incubation with DCA, respectively. The effects of PDGF such as proliferation and migration of VSMCs were promoted after a 48-h incubation with DCA despite the absence of DCA during PDGF stimulation. These findings suggest that elevated serum concentrations of DCA are involved in the pathogenesis of atherosclerosis in HF-induced obesity.

Acyl-homoserine lactones suppresses IEC-6 cell proliferation and increase permeability of isolated rat colon

We investigated to determine whether a variety of acyl-homoserine lactones (AHLs) influences epithelial cell proliferation and mucosal permeability. 3-Oxo-C12-homoserine lactone (HSL) and 3-oxo-C14-HSL significantly suppressed IEC-6 cell proliferation. A significant increase in mucosal permeability was observed in isolated rat colon tissue exposed to C12-HSL, 3-oxo-C12-HSL, and 3-oxo-C14-HSL. These data indicate that AHLs suppress epithelial proliferation and disrupt barrier function in intestinal mucosa.

Zinc deficiency induces dysregulation of cytokine productions in an experimental colitis of rats

Dextran sulfate sodium (DSS)-induced colitis is an experimental model of ulcerative colitis, although the precise mechanism has not yet been elucidated. We investigate whether Zn deficiency affects the pathogenesis of colitis induced by DSS with a focus on immune responses. Male WKAH/Hkm Slc rats were fed either a Zn-adequate (ZA, 30 mg Zn/kg diet) as a control or Zndeficient (ZD, 5 mg Zn/kg diet) diet for 21 days and then treated with 2% DSS via deionized drinking water for 7 days. The disease activity index (DAI) was recorded daily throughout DSS treatment. Serum Zn concentrations were significantly lowered in rats fed the ZD diet than those fed the ZA diet at day 7 and 14. Surprisingly, DSS treatment considerably reduced the serum Zn in both groups. The rats fed the ZD diet showed exacerbated colitis based on clinical outcomes, including weight loss, increased DAI, and shortened colon length. An in vitro study corroborated these results, showing that a large amount of TNFα was induced by rat mesenteric leukocytes in response to lipopolysaccharide in ZD medium, but not in ZA medium. These results indicate that a modulation of TNFα production due to Zn deficiency influences disease activity in DSS-induced colitis. In addition, more attention should be given to Zn for prevention of colitis.

The delay in the development of experimental colitis from isomaltosyloligosaccharides in rats is dependent on the degree of polymerization

Background

Isomaltosyloligosaccharides (IMO) and dextran (Dex) are hardly digestible in the small intestine and thus influence the luminal environment and affect the maintenance of health. There is wide variation in the degree of polymerization (DP) in Dex and IMO (short-sized IMO, S-IMO; long-sized IMO, L-IMO), and the physiological influence of these compounds may be dependent on their DP.

Methodology/Principal Findings

Five-week-old male Wistar rats were given a semi-purified diet with or without 30 g/kg diet of the S-IMO (DP = 3.3), L-IMO (DP = 8.4), or Dex (DP = 1230) for two weeks. Dextran sulfate sodium (DSS) was administered to the rats for one week to induce experimental colitis. We evaluated the clinical symptoms during the DSS treatment period by scoring the body weight loss, stool consistency, and rectal bleeding. The development of colitis induced by DSS was delayed in the rats fed S-IMO and Dex diets. The DSS treatment promoted an accumulation of neutrophils in the colonic mucosa in the rats fed the control, S-IMO, and L-IMO diets, as assessed by a measurement of myeloperoxidase (MPO) activity. In contrast, no increase in MPO activity was observed in the Dex-diet-fed rats even with DSS treatment. Immune cell populations in peripheral blood were also modified by the DP of ingested saccharides. Dietary S-IMO increased the concentration of n-butyric acid in the cecal contents and the levels of glucagon-like peptide-2 in the colonic mucosa.

Conclusion/Significance

Our study provided evidence that the physiological effects of α-glucosaccharides on colitis depend on their DP, linkage type, and digestibility.

Mucosal permeability is an intrinsic factor in susceptibility to dextran sulfate sodium-induced colitis in rats

We investigated differences in the pathogenesis of dextran sulfate sodium (DSS)-induced colitis between two inbred rat strains, Wistar King A Hokkaido (WKAH) and Dark Agouti (DA) rats, to determine the intrinsic factors responsible for the development of colitis. DSS exposure exacerbated the clinical symptoms such as body weight loss, stool consistency and rectal bleeding in DA rats rather than that in WKAH rats. Additionally, the average survival was shorter in DA rats than in WKAH rats. The expression levels of tumor necrosis factor-α, interleukin (IL)-12 p35 and IL-23 p19 increased prominently in the DA rats that were administered DSS, accompanied by severe infiltration of leukocytes into the colon. We also found that colonic permeability was greater in the DA rats than in the WKAH rats. In Ussing chambers, exposure of the isolated colon tissue to DSS enhanced the colonic permeability of both strains. Immunoblot analysis revealed that the expression levels of tight junction (TJ) proteins were modulated during DSS administration. Higher expression levels of claudin-4 and junctional adhesion molecule-A proteins were observed in DA rats than in WKAH rats, even in intact conditions. These results indicated that the expression pattern of TJ proteins determines the colonic permeability of the rats. In conclusion, the intrinsic colonic permeability is one of critical factors responsible for the susceptibility of rats to colitis.

Marginal zinc deficiency exacerbates experimental colitis induced by dextran sulfate sodium in rats

We investigated the impact of Zn status on the maintenance of mucosal homeostasis. Rats were fed diets containing different amounts of Zn (30, 10, 5, <1 mg Zn/kg diet) for 21 d. Serum Zn concentrations were lower in rats fed marginally Zn-deficient (MZD; 5 mg Zn/kg diet) and severely Zn-deficient (<1 mg/kg) diets but not in those fed the marginally Zn-adequate diet (10 mg/kg) or the Zn-adequate (ZA; 30 mg/kg) group (P < 0.05). However, organ weights, colonic epithelial cell proliferation, and crypt fission did not differ between the MZD and ZA groups. We then evaluated whether MZD modulated dextran sulfate sodium (DSS)-induced colonic inflammation by administering 2% DSS to the MZD and ZA groups for 7 d. Myeloperoxidase activity and TNFα production increased in response to DSS in the MZD group (P < 0.03). Colonic permeability in the 2 groups did not differ after DSS administration. In a culture experiment using isolated mesenteric leukocytes, TNFα production was higher (P < 0.05) and TNF receptor type I (TNFR1) expression was detected in culture medium containing 20 and 30 μmol/L of Zn compared with culture medium lacking Zn supplementation. These results suggest that MZD exacerbated colitis by modulating the immune response through the impairment of TNFα production and TNFR1 expression rather than through the impairment of epithelial barrier function.

Androgen-producing ovarian tumors: a clinicopathological study of 3 cases

The clinical course and pathological findings of 3 rare cases of androgen-producing ovarian tumors are presented. The ages of the 3 patients (Cases 1, 2, and 3, respectively) were 43, 34, and 57 years, respectively. Their preoperative serum testosterone levels were 506, 491, and 231 ng/dl, respectively. The pathological diagnoses of Cases 1, 2, and 3 were a Sertoli-stromal cell tumor of intermediate differentiation, a stromal tumor containing Leydig cells, and a stromal tumor with minor sex cord elements, respectively. Patient 1 experienced a recurrence, of a lesion at the vaginal stump 1 year and 2 months after the initial surgery. The clinical courses of Cases 2 and 3 have been non-contributory.

Usefulness of endometrial aspiration cytology for the preoperative diagnosis of ovarian carcinoma

OBJECTIVE

To evaluate the usefulness of endometrial aspiration cytology for the preoperative diagnosis of ovarian carcinoma.

STUDY DESIGN

A total of 210 patients with ovarian carcinoma were investigated by endometrial aspiration cytology.

RESULTS

Fifty-five of 210 patients (26.2%) had positive endometrial aspiration cytology. The positive rates of endometrial cytology were 3.9% in stage I, 23.8% in stage II, 36.5% in stage III and 53.3% in stage IV. When classified by histologic type, the positive rates of endometrial cytology in patients with serous adenocarcinoma, mucinous adenocarcinoma, clear cell adenocarcinoma, undifferentiated carcinoma and yolk sac tumor were 38.9%, 11.8%, 21.1%, 16.7% and 16.7%, respectively. One hundred twenty-eight of 210 patients (61.0%) were positive on peritoneal cytology, and 54 of these 128 cases (42.2%) were also positive on endometrial cytology. The positive rates of endometrial cytology were especially high in patients with serous adenocarcinoma (51.2%) and those with clear cell adenocarcinoma (40.0%) among those who were positive on peritoneal cytology. Of 74 patients who were negative on peritoneal cytology, only one (1.4%) with mucinous adenocarcinoma had positive endometrial cytology. Hysterectomy was performed on 130 patients, and the positive rate of endometrial cytology was 100% in 4 patients with endometrial invasion and 15.9% in 126 cases without invasion.

CONCLUSION

Endometrial aspiration cytology can detect ovarian carcinoma cells not only in patients with endometrial involvement but also in patients with positive peritoneal cytology. Endometrial aspiration cytology appears to be useful for the preoperative diagnosis of ovarian carcinoma.