Reduced ratio of protective versus proinflammatory cytokine responses to commensal bacteria in HLA-B27 transgenic rats.

Germ-free HLA-B27 transgenic (TG) rats do not develop colitis, but colonization with specific pathogen-free (SPF) bacteria induces colitis accompanied by immune activation. To study host-dependent immune responses to commensal caecal bacteria we investigated cytokine profiles in mesenteric lymph node (MLN) cells from HLA-B27 TG versus nontransgenic (non-TG) littermates after in vitro stimulation with caecal bacterial lysates (CBL). Supernatants from CBL-stimulated unseparated T- or B- cell-depleted MLN cells from HLA-B27 TG and non-TG littermates were analysed for IFN-gamma, IL-12, TNF, IL-10 and TGF-beta production. Our results show that unfractionated TG MLN cells stimulated with CBL produced more IFN-gamma, IL-12 and TNF than did non-TG MLN cells. In contrast, CBL-stimulated non-TG MLN cells produced more IL-10 and TGF-beta. T cell depletion abolished IFN-gamma and decreased IL-12 production, but did not affect IL-10 and TGF-beta production. Conversely, neither IL-10 nor TGF-beta was produced in cultures of B cell-depleted MLN. In addition, CD4(+) T cells enriched from MLN of HLA-B27 TG but not from non-TG rats produced IFN-gamma when cocultured with CBL-pulsed antigen presenting cells from non-TG rats. Interestingly, IL-10 and TGF-beta, but not IFN-gamma, IL-12 and TNF were produced by MLN cells from germ-free TG rats. These results indicate that the colitis that develops in SPF HLA-B27 TG rats is accompanied by activation of IFN-gamma-producing CD4(+) T cells that respond to commensal bacteria. However, B cell cytokine production in response to components of commensal intestinal microorganisms occurs in the absence of intestinal inflammation.

Differential expression of vasoactive intestinal polypeptide receptor 1 and 2 mRNA in murine intestinal T lymphocyte subtypes.

Neuropeptides may exert a variety of effects on the immune cells at both systemic and mucosal immune sites. The immunoregulatory properties refer to the ability of physiological signals and pathways to influence various immune functions. Vasoactive intestinal polypeptide (VIP), a neuropeptide present in high concentration in gut, was studied for its production and receptor expression in intraepithelial and lamina propria T lymphocytes of mouse intestine. Using reverse transcription-polymerase chain reaction (RT-PCR) analysis, it was demonstrated that VIP receptor 1 (VIPR1) was constantly expressed in intraepithelial and lamina propria T lymphocytes from both small and large intestine. In contrast, VIPR2 was identified only in T cells from small intestine. Further studies on purified subpopulations of T lymphocytes indicated the existence of VIPR2 in CD8(+) T cells, but not CD4(+) and CD4CD8 double negative T cells, although all these three subpopulations displayed VIPR1. In addition, VIPR1 mRNA was detected in splenic T lymphocytes, but no signal was obtained for VIPR2 mRNA, even after stimulation of the cells with anti-CD3(epsilon)-chain mAb, phorbol 12-myristate 13-acetate (PMA) and/or VIP. The presence of VIP receptor(s) on intestinal T lymphocytes was supported by the detection of VIP on the cell surface using dual colour immunoflowcytometry. In-vitro treatment with VIP resulted in a tendency towards an increased size of the VIP immunoreactive T cell population and significantly enhanced the average immunofluorescence intensity of the surface labelling. This indicates that the receptors are partially occupied by locally produced VIP in vivo and that more peptide molecules can be bound on the lymphocytes when needed, released and accumulated in higher concentration at the action sites. We failed to detect the expression of VIP mRNA in T lymphocytes, from either intestine or spleen. These observations support that VIP may be an important immune modulator in gut acting through specific receptors on T lymphocytes. The differential mRNA expression of VIP receptor subtypes in cells with different phenotypes and in different immune compartments may suggest diverse regulatory roles of the neuropeptide in immune responses.

Both substance P and its receptor are expressed in mouse intestinal T lymphocytes.

Substance P (SP), one of the most prevalent neuropeptides in gut, has been reported to have potent immune modulatory effects as a proinflammatory agent. The synthesis of SP and SP receptor expression in intraepithelial and lamina propria T lymphocytes of mouse intestine was investigated. Using RT-PCR analysis, it was demonstrated that SP receptor mRNA was exclusively expressed in intraepithelial and lamina propria T lymphocytes as well as their purified CD4+, CD8+ and CD4-CD8-CD3+ subsets. Messenger RNAs (mRNAs) for the two precursors of SP, beta and gamma-preprotachykinin-A, were also detected. These results were consistent in lymphocytes from both epithelium and lamina propria of small and large intestines, although the frequencies and/or intensities of mRNA expression varied. However, none of the findings could be repeated in splenic T lymphocytes. Activation of splenocytes with anti-CD3epsilon-chain mAb and PMA did not induce expression of SP or its receptor mRNAs. Furthermore, both cytoplasmic and surface-bound SP was demonstrated in intestinal T lymphocytes using dual color immunocytochemistry and immunoflow cytometry. In vitro treatment with SP did not significantly change the size of the SP-immunoreactive T cell population, indicating the presence of SP receptor on intestinal T lymphocytes as well as in vivo binding of endogenously released SP. Our data suggest that SP production and SP receptor expression are distinctive for mouse intestinal mucosal immunity and that SP may act as a modulator of an ongoing controlled inflammation in normal gut, by acting through its specific receptor on T lymphocytes in an autocrine and/or paracrine pattern.

Neuroendocrine changes in colon of mice with a disrupted IL-2 gene.

Neuroendocrine peptides have a variety of physiological functions in the gastrointestinal tract. This study was carried out to investigate the impact of IL-2 deficiency on the neuroendocrine system in normal colon, and the neuroendocrine changes during colonic inflammation. Mice with homozygous disrupted IL-2 gene (IL-2-/-) spontaneously developed a bowel disease with similarities to human ulcerative colitis. Different types of colonic endocrine cells and myenteric nerves were analysed in the IL-2-/- mice using immunomorphometry. The neuropeptide contents in the colonic tissues were determined by radioimmunoassay. Age-matched healthy IL-2+/- and IL-2+/+ mice served as controls and the colonic IL-2 levels were compared between these two groups of mice by ELISA. Our data showed that less than half the amount of IL-2 was synthesized in the colon of IL-2+/- mice compared with the IL-2+/+ wild-type mice. Two major differences in the neuroendocrine colon were found between the mice with an intact and disrupted IL-2 gene. One was age-related. The frequencies of various endocrine cells and myenteric nerves increased with age in the IL-2+/+ mice. However, no such increases were seen in the mice with a disrupted IL-2 gene. Instead, the volume densities of enteroglucagon, serotonin cells and substance P (SP), vasoactive intestinal polypeptide (VIP) and total myenteric nerves were lower in the older IL-2+/- and IL-2-/- mice compared with the wild type. The other was disease-related. Polypeptide YY (PYY) cells and tissue levels of PYY, SP and VIP were significantly decreased in the IL-2-/- mice during the course of bowel inflammation compared with the healthy IL-2+/- and IL-2+/+ controls. These findings indicate that colonic neuroendocrine alterations did occur in the mice with a disrupted IL-2 gene and diminished local IL-2 level, suggesting a role of IL-2 in the regulation of the neuroendocrine system and a prevalent interaction between the immune and neuroendocrine systems in normal colon. On the other hand, there were some changes that seemed to correlate with the bowel inflammatory process. They might be associated with the impaired function in inflamed gut and contribute to the development and/or prolongation of disease.

Neuroendocrine peptide levels in the gastrointestinal tract of mice after unilateral cervical vagotomy.

The effects of left and right unilateral cervical vagotomy on the content of several neuroendocrine peptides were studied in different parts of the murine gastrointestinal tract, known to receive vagal innervation. The neuroendocrine peptides investigated were secretin, gastric inhibitory peptide (GIP), gastrin, motilin, peptide YY (PYY), somatostatin, substance P, VIP, neurotensin, neuropeptide Y (NPY), and galanin. The neuroendocrine peptide concentration was affected after both left and right vagotomy, and that the changes in the concentrations of the neuroendocrine peptide levels occurred in all the gastrointestinal segments investigated, namely antrum, small and large intestine. However, these changes varied, depending on which side was vagotomized and the interval after vagotomy. It is concluded that the vagus nerve had an important impact on the neuroendocrine system in the murine gut. It is suggested, furthermore that the contradictory results obtained earlier on the effect of vagotomy on the gastrointestinal peptides may depend on differences in the vagotomy methods used and on differences in observation time after vagotomy.

Effects of unilateral cervical vagotomy on antral endocrine cells in mouse.

The present study was carried out to investigate the effect of unilateral cervical vagotomy on the antral endocrine cells in mouse. Fifty-four mice were randomly divided into three groups, 18 in each, for left or right cervical vagotomy, or sham operation as controls. The animals were sacrificed 2, 4, and 8 weeks after the operation, respectively. Chromogranin-, gastrin/CCK-, serotonin-, and somatostatin-cells were detected by immunohistochemistry and quantitated by computerised image analysis. The results showed that the number of chromogranin-cells was decreased in both left and right vagotomized mice after 4 weeks and remained at the same level after 8 weeks. The numbers of gastrin-, serotonin- and somatostatin-cells did not change after right vagotomy. However, the numbers of gastrin- and somatostatin-cells were decreased after left vagotomy, whereas no change was found in serotonin-cells. Endocrine cells with vacuolated cytoplasm and pyknotic nuclei were also observed during the course of time. The alteration in the antral endocrine cells observed in this study seemed to be dynamic and depended on the observation time after the operation as well as the denervated branches of the vagus nerve. This may explain, at least partially the contradictory results obtained earlier by different investigators.

Changes in intestinal endocrine cells in the mouse after unilateral cervical vagotomy.

The effect of right or left unilateral cervical vagotomy on the intestinal endocrine cells was studied in 23 mice at 2 and 8 weeks after operation, respectively. The results were compared with that from 10 sham operated mice. Various types of endocrine cells in duodenum and proximal colon were detected by immunohistochemistry and quantified by computerized image analysis. In mouse duodenum, chromogranin-, CCK/gastrin-, GIP- and somatostatin-cells were significantly decreased at 2 weeks after right vagotomy, but returned to the control levels at 8 weeks. Serotonin-cells were reduced at both 2 and 8 weeks after right vagotomy. The amount of the duodenal endocrine cells did not change after left vagotomy with the exception of secretin-cells, which were diminished at 8 weeks after both right and left vagotomy. In the proximal colon, chromogranin-cells were also decreased at 2 weeks after right vagotomy. Serotonin-cells were reduced at 8 weeks after left vagotomy but not right vagotomy. There was no significant difference between the unilaterally vagotomized and the sham operated mice with regard to PYY- and glucagon-cells. It was concluded that vagotomy affected the intestinal endocrine cells in mouse. The influence was more pronounced in the small intestine than the proximal colon. The right vagus nerves seemed to exert more effect on the intestinal endocrine cells than the left ones.

[Total hip arthroplasties in 190 cases: follow-up study].

One hundred and ninety-six cemented total hip arthroplasties performed in 190 patients (mean age, 62 years) followed-up with an average of 8.7 years were reviewed. The results were compared with the same group previously reported at an average follow-up of 4 years. Clinically satisfactory results were observed at the short- and medium-terms. Evaluation of the study with Harris score system showed that the score records fell from 85 to 78.4 points in the same group and the revision rate rose from 6.84% to 14.73%. The main causes of the prosthesis failure were loosening of the prosthesis and of breakage of the prosthesis stem. This follow-up study showed that the short-term prosthesis failure was mainly related to the cement-fixing technique, while the medium-term failure was due to side effects of the cement. This series showed that cemented prosthesis is a good selection especially for elderly patients.