The significance of colonic mucosal lymphoid hyperplasia and aphthoid ulcers in Crohn's disease

OBJECTIVE

To access concordance between radiological severity of aphthae and the more advanced features of Crohn's disease.

PATIENTS AND METHODS

In 75 patients with an established diagnosis of Crohn's disease, we evaluated the radiological severity of colonic aphthae by meticulous double-contrast radiography. The degree of aphthae was defined as follows: AE0 = no lesions; AE1 = small nodules without barium flecks (lymphoid hyperplasia); AE2 = minute barium flecks < or = 1 mm in size with a translucent halo (umbilical or eroded lymphoid hyperplasia); AE3 = barium flecks varying from 2 mm to 5 mm in size (typical aphthoid ulcerations). We compared the degree of the lesions to the disease activity, and reviewed these sequential changes during a mean interval of 10 months.

RESULTS

AE3 lesions were more prevalent than AE1 or AE2 lesions in patients with active colitis. AE1 or AE2 lesions were found regardless of the involved bowel sites or the disease activity. Of 44 patients receiving a nutritional diet, 26 patients showed regression of the lesions although most of the patients still exhibited AE1 or AE2 lesions. In two of eight patients without the treatment, the lesions progressed.

CONCLUSION

In Crohn's disease, development of aphthoid ulcers is associated with disease activity; lymphoid hyperplasia may exist independently of disease activity.

Nonpolypoid adenomas of the duodenum in patients with familial adenomatous polyposis (Gardner's syndrome)

BACKGROUND

Although duodenal adenomas are very common in familial adenomatous polyposis, we wished to emphasize our experience with finding nonpolypoid adenomas in the duodenum of patients with this disease.

METHODS

Duodenoscopy was performed in 23 patients with an established diagnosis of familial adenomatous polyposis or Gardner's syndrome.

RESULTS

Endoscopy revealed single or multiple nonpolypoid adenomas of the duodenum in 7 patients (30%). The lesions were smaller than 5 mm and were endoscopically recognized as flat or depressed reddish lesions; one lesion was completely flat and the remaining lesions were flat-topped elevations with a central depression. All of the lesions were histologically diagnosed as tubular adenoma with moderate epithelial atypia.

CONCLUSION

These findings suggest that duodenal nonpolypoid adenomas are common in familial adenomatous polyposis or Gardner's syndrome and that careful surveillance endoscopy seems necessary in patients with this disease.

Myofibroblastic tumor of soft tissue displaying desmin-positive and actin-negative immunophenotypes

Myofibroblasts have ultrastructural and functional characteristics intermediate between fibroblasts and smooth muscle cells. Previous studies indicated that most myofibroblasts express actin and vimentin but not desmin immunophenotypes. Two benign intramuscular myofibroblastic tumors which displayed a desmin-positive and actin-negative immunophenotype are reported. The tumors occurred on the back of a 45 year old man who had neurofibromatosis 1 and the thigh of a 37 year old man without neurofibromatosis. Both tumors were encapsulated and composed of short intersecting bundles of spindle cells in a collagenous background. Although the tumors were cellular, nuclear pleomorphism was minimal and mitotic figures were rare. Characteristically, most tumor cells were immunoreactive strongly for desmin and vimentin but gave negative staining for muscle-specific actin, alpha-smooth muscle actin, alpha-sarcomeric actin, myosin, S-100 protein, cytokeratins, and CD34. On electron microscopy, the tumor cells were characterized by short spindle-indented nuclei, abundant cytoplasmic intermediate filaments, prominent plasmalemmal pinocytosis and frequent cell coverage by basal lamina. Aggregation of thin myofilaments with focal condensations was identified occasionally. Although the tumors showed distinct morphological and immunohistochemical features enabling delimitation from other soft tissue lesions, they may overlap histologically with myofibroblastoma of the breast, lymph node and soft tissue, low grade malignant nerve sheath tumor, leiomyosarcoma, cellular schwannoma, inflammatory fibrosarcoma and nodular fasciitis.

Immunohistochemical localization of activin A and follistatin in human tissues

We immunohistochemically investigated the localization of activin A and follistatin in various human tissues with specific antibodies to recombinant human (rh-) activin A and rh-follistatin. Specific immunostaining of activin A was detected in Leydig and Sertoli cells of the testis. In the ovary, granulosa cells of mature follicle and luteal cells of the corpus luteum stained for activin A. Immunoreactive activin A was present in somatotrophs of the pituitary gland and insulin-positive B cells of the pancreatic islets. Immunoreactivity for activin A was also found in thyroid follicular cells, adrenocortical cells, neuronal cells of the cerebrum and monocytoid cells in the bone marrow. Follistatin, an activin-binding protein, was immunostained in the same tissues as activin A. These findings indicated that activin A and follistatin are widely distributed in human tissues, suggesting that activin plays important roles as a common regulator in various tissues under the control of co-existing follistatin.

Association between thyroid cancer of cribriform variant and familial adenomatous polyposis

A case of a 20 year old Japanese woman who developed thyroid cancer exhibiting unusual cribriform structures while being followed up for familial adenomatous polyposis/Gardner's syndrome is reported. The patient presented with osteomas, pigmented retinal lesions, and adenomas of the duodenum and the papilla of Vater, in addition to numerous adenomatous polyps in the colorectum. On ultrasonography, the thyroid cancer was localised to the right lobe and was identified as an irregular, internal echo tumour with a peripheral hypoechoic zone, measuring 1.8 cm in diameter. Histological examination of the resected tumour showed a concomitance of papillary proliferation and cribriform structures with follicles of varying sizes. These features can be distinguished from sporadic thyroid cancer.

Evidence of HTLV-I in thyroid tissue in an HTLV-I carrier with Hashimoto's thyroiditis

Human T-lymphotropic virus type l (HTLV-I) protein and messenger RNA (mRNA) for HTLV-I were examined in thyroid tissues from two patients with Hashimoto's thyroiditis and serum anti-thyroid antibody. The virus envelope protein and signals for the mRNA were detected in many of the follicular epithelial cells of the thyroid tissue from one of the patients, respectively, by immunohistochemistry and in situ hybridization. PCR-Southern blotting revealed the presence of HTLV-I DNA in the thyroid tissue, in which the viral protein and mRNA were detected, although no virus particles were found in the epithelial cells by electron microscopy. HTLV-I virus was not present in the thyroid tissue from the second patient. The present findings suggest that infection of thyroid tissue with HTLV-I is associated with the pathogenesis of Hashimoto's thyroiditis in some patients.

Ultrastructural heterogeneity of acquired intradermal melanocytic nevus cells

The present ultrastructural evaluation of 12 acquired intradermal melanocytic nevi revealed that in contrast to the nested epithelioid melanocytic nevus cells of the upper dermis, the spindle nevus cells of the deep dermis showed perineurial differentiation, exhibiting a spindly configuration characterized by a melanosome-free cytoplasm that showed extremely slender bipolar contour and contained abundant intermediate filaments, a decreased number of cytoplasmic organelles, and, significantly, a fair number of plasmalemmal pinocytotic vesicles. The nevic corpuscles were found to consist of laminated slender cytoplasm showing subcellular conformation similar to that of the spindle nevus cells. By immunohistochemistry, many spindle nevus cells and nevic corpuscles were immunoreactive for nerve growth factor receptor. All the nevus cells were immunoreactive for vimentin and S-100 protein, and negative for protein gene product 9.5, epithelial membrane antigen, Leu-7, and myelin basic protein. Characteristically, protein gene product 9.5 immunohistochemistry revealed numerous immunoreactive axons intermingled with the spindle nevus cells in the deep portion. All the PGP9.5-immunoreactive axons were observed by immunoelectron microscope to be unmyelinated and always ensheathed by a thin cytoplasmic process of Schwann cells but not nevus cells. These findings indicate that differentiation plasticity exists in the various nevus cells, with the epithelioid nevus cells and the spindle nevus cells displaying more ultrastructural and immunophenotypical characteristics of melanocyte and perineurial cells, respectively, suggesting that a pluripotential cell of neural crest origin accounts for the histogenesis of this lesion.

Use of endosonographic evaluation of colorectal tumor depth in determining the appropriateness of endoscopic mucosal resection

OBJECTIVES

To determine the efficacy with which endoscopic ultrasonography (EUS) is able to differentiate between mucosal and submucosal invasion for application of endoscopic resection.

METHODS

We prospectively analyzed 60 patients who were diagnosed with early cancer by conventional EUS with regard to the accuracy of mucosal neoplasia as a function of gender, age, location, size, endoscopic configuration, histological diagnosis, and method of resection.

RESULTS

Forty lesions interpreted as mucosal by EUS were shown histologically to include 32 lesions in the mucosa and eight in the submucosa or deeper, whereas 20 tumors interpreted as invasive cancer included six lesions in the mucosa and 14 in the submucosa or deeper. The accuracy of mucosal neoplasia (AMN) detection was 77% (true-positive and true-negative mucosal neoplasias divided by all lesions). Assessment of pure cancers without adenomatous components produced a significantly lower AMN (59%, p = 0.03) than the assessment of pure adenomas (95%) or cancers in adenomas (87%). However, there were no significant differences in the EUS assessment of intramucosal neoplasia as a function of sex, age, endoscopic configuration, size, location, or treatment.

CONCLUSIONS

We conclude that conventional EUS interpretation alone cannot determine the appropriate treatment for early colorectal cancer.

Primary jejunal malignant mixed tumor in a patient with von Recklinghausen neurofibromatosis

A rare case of primary jejunal malignant mixed tumor arising in a 49-64-old Japanese male with von Recklinghausen's disease is reported. The patient, who had a past history of partial gastrectomy due to duodenal ulcer, was admitted with a complaint of epigastric pain. Upper gastrointestinal examinations showed a huge polypoid tumor located in the efferent loop of the gastrojejunostomy site. Because the tumor was strongly suggestive of leiomyosarcoma on histological examination of biopsy specimens, laparotomy was performed. The resected tumor measuring 10 X 7 X 7 cm was composed of adenocarcinoma admixed with various sarcomatous components, including rhabdomyosarcoma, osteosarcoma, and other sarcomas. Immunohistochemical analysis also supported this diagnosis. The features of this tumor closely resembled malignant mixed mullerian tumor of heterologous type that develops in female genital organs. It is well known that patients with von Recklinghausen neurofibromatosis have an increased incidence of mesenchymal tumors and malignant neoplasias, and therefore, it seems that there is a possible relationship between the histogenesis of this peculiar tumor and the genetic abnormality in this patient.

Pulmonary blastoma: an ultrastructural and immunohistochemical study with special reference to nuclear filament aggregation

A case is presented of pulmonary blastoma occurring in the right upper lobe of a 25-year-old man without distinct clinical features and laboratory abnormality. Light microscopic analysis revealed that the tumor was composed of branching glands and morulae embedded in a primitive but bland mesenchyme. Immunohistochemically the epithelial cells were immunoreactive for cytokeratins, S-100 protein, protein gene product 9.5, chromogranin A, calcitonin, and Ki-67 (MIB-1); the mesenchymal cells were immunoreactive for vimentin, actin, cytokeratins, and Ki-67; and all the tumor cells were negative for p53, estrogen receptor protein, and human chorionic gonadotropin beta. Characteristically, many epithelial cells contained optically clear nuclei which were immunoreactive for biotin (M743). Electron microscopic analysis revealed that the optically clearing change was due to replacement of the central area of the nuclei by a mass of parallel-arranged 7- to 10-nm filaments, and biotin-immunoreactive products were mainly localized in the nuclear matrix. Additionally, spherical bodies were identified in the cytoplasm of the nuclear filament-aggregated cells, suggestive of an intimate pathogenetic association of the two morphological abnormalities. The similarity of the aggregated nuclear filaments to those observed in gestational endometrium and ovarian endometrioid carcinoma implies that a similar mechanism plays a role in the pathogenesis of these abnormalities.

Prognostic implication of the p53 protein and Ki-67 antigen immunohistochemistry in malignant fibrous histiocytoma

BACKGROUND

Mounting evidence indicates that p53 regulates cell growth and abnormal p53 immunophenotypic expression is associated with an unfavorable prognosis for patients with some types of carcinoma. The prognostic significance of p53 overexpression in malignant fibrous histiocytomas (MFHs) of soft tissue has not yet been elucidated.

METHODS

Expressions of p53 protein and Ki-67 antigen in 54 primary MFHs of soft tissue were investigated immunohistochemically and indexed quantitatively by counting the number of immunoreactive nuclei versus the total neoplastic nuclei in the representative fields of each tumor to evaluate their prognostic implications and interrelations with other clinicopathologic parameters.

RESULTS

The percentages (labeling indices [LIs]) of p53 and Ki-67-immunoreactive nuclei versus the total neoplastic nuclei were 0.1-93.2% (mean +/- standard deviation [SD], 40.6% +/- 21.8%) and 5.3-90.8% (mean +/- SD, 42.7% +/- 29.4%), respectively. The Ki-67 LI correlated with histologic grade (P = 0.01498), primary tumor size (P = 0.04985), disease free interval (reverse correlation, P = 0.00776), and recurrence and metastasis (P = 0.00360). The p53 LI correlated with primary tumor size (P = 0.00431) but did not show any significant correlation with histologic grade, Ki-67 LI, primary tumor size, disease free interval, or recurrence and metastasis. Other significant correlations included histologic grade and disease free interval (P = 0.00010), primary tumor size and disease free interval (reverse correlation, P = 0.00869), histologic grade and recurrence (P = 0.02714), and primary tumor size and primary tumor location (P = 0.00028). In the grouped survival analysis, patients with recurrence or metastasis or with tumors of larger size (> or = 7 cm), high histologic grade, or higher Ki-67 LI (> or = 25%) had a significantly reduced survival (P < 0.05). The different p53 immunohistochemical expression and the different histologic types did not reflect different cumulative survival (P > 0.05). Regression analysis revealed that the primary tumor size and histologic grade, but not Ki-67 or p53 LIs, were independent statistical variables for prognostication.

CONCLUSIONS

These results indicate that (1) primary tumor size and histologic grade are two important prognostic factors, (2) Ki-67 LI should be used in adjunct with other main prognostic factors for patients with MFHs, and (3) nuclear p53 overexpression in MFHs of soft tissue is a comparatively common event that has no prognostic implication.

Differentiation and proliferative activity in benign and malignant cartilage tumors of bone

To assess the histological grade in benign and malignant cartilage tumors of bone by more objective methods, we examined the differentiation and proliferative activity of tumor cells in six enchondromas, five chondroblastomas, and 13 chondrosarcomas immunohistochemically. A variable number of cells in all tumors showed S-100 protein and vimentin immunoreactivity. In fully differentiated cartilage of enchondromas and low grade chondrosarcomas, tenascin, which is an extracellular matrix glycoprotein, was present in small amounts or absent but was increased at the periphery of tumor lobules and even in the matrix throughout the high grade chondrosarcomas. Higher rate and intensity of proliferating cell nuclear antigen (PCNA) reactivity were found in chondrosarcomas, especially in spindle-shaped cells of high grade tumors, than in enchondromas. The distribution of PCNA-positive cells almost corresponded to the regions with tenascin reactivity. One tumor of high grade chondrosarcoma showed p53 protein immunoreactivity. Aberrant expression of cytokeratin was observed in four chondroblastomas. The expression of desmin was identified in relatively large proportions of enchondromas and chondrosarcomas, regardless of their benign or malignant nature and histological grade. Smooth muscle or muscle-specific actins also were present in a smaller number of tumors. Based on these findings, it is concluded that unusual staining characteristics were present, in addition to those of a chondroblastic nature, in the cartilage tumors of bone. Tenascin and PCNA positivity of various degrees in all chondroblastomas may suggest that they are chondrogenic tumors having a relatively high proliferative activity, albeit their benign clinical course. Proliferative activity of tumor cells in enchondromas and chondrosarcomas correlated well with their histological grade. Tenascin may play a role in promoting tumor cell proliferation of cartilagenous neoplasms and, on the other hand, the alterations of extracellular matrix involving tenascin synthesis seem to be a result of tumor development.

Possible neoplastic transformation within gastric hyperplastic polyp. Application of endoscopic polypectomy

A total of 263 gastric hyperplastic polyps, which had been removed endoscopically from 202 patients, were clinicopathologically analyzed. Among these polyps, there were nine polyps with neoplastic components (3.4%), corresponding to adenoma in five lesions and mucosal adenocarcinoma in four lesions. Comparing the neoplastic transformed polyps with the pure hyperplastic polyps, there was no significant difference according to age, gender, location, gross appearance, or size. However, the transformed polyps which were located in the lower third of the stomach were larger in size (mean, 20.8 mm) and were more likely to be found among older patients (mean, 75.8 years) than were the pure hyperplastic polyps (mean size and age: 14.5 mm and 61.8 years). These results may indicate the possibility of a different carcinogenesis belonging to gastric hyperplastic polyps by location, and this finding seems to be significant in the application of endoscopic polypectomy.

Aneurysmal fibrous histiocytoma of the skin. A histological, immunohistochemical, and ultrastructural study

We present two cases of aneurysmal fibrous histiocytoma of the skin on the lower extremities of a 41-year-old man and a 23-year-old woman. Both the tumors appeared clinically as cutaneous nodules with a recent history of rapid growth and showed microscopically a unique formation of blood-filled tissue spaces and a storiform proliferation of histiocyte-like and fibroblast-like cells in a capillary-rich stroma. Such clinical and histologic features fit the original description of this entity. Immunohistochemically the tumor cells of both cases were immunoreactive for factor XIIIa, Mac 387, and vimentin and gave negative results for factor VIII-related antigen, desmin, actin, and S-100 protein. Ultrastructurally the tumors were composed mainly of siderosome-containing histiocyte-like cells, fibroblast-like cells, and intermediate cells and lacked prominent proliferation of endothelial cells. Thus, the ultrastructural findings agreed with the immunophenotypes expressed by the tumor cells, supporting the fibrohistiocytic origin of this lesion. In view of the recent rapid growth, the presence of hemorrhagic pseudocysts, the extravasation of erythrocytes, and the high vascularity of the present tumors, we emphasize the importance of distinguishing this lesion from angiomatoid fibrous histiocytoma and cutaneous malignancies of mesenchymal origin.

Endoscopic evaluation of gastric inflammatory fibroid polyp

Clinical and endoscopic manifestations of 18 gastric inflammatory fibroid polyps (IFP) in 16 patients who underwent endoscopic or surgical removal were retrospectively analyzed. All of the lesions were located within the pyloric antrum, and the sizes varied from 0.8 to 7.0 cm. On endoscopy, six polyps which measured 1.0 cm or less uniformly seemed to be sessile or intramural tumors, whereas four of the nine polyps between 1.1 and 2.0 cm in size were additionally accompanied by a central depression. The remaining three, which measured more than 2.0 cm, showed characteristic polypoid growth with ulcerations. Three polyps more than 1.0 cm in size occasionally prolapsed into the duodenal bulb. Three patients with these prolapsing polyps and two with polyps accompanied by ulcerations experienced abdominal pain, nausea, or severe anemia. Two polyps (11%) were precisely diagnosed as IFP by means of conventional forceps biopsy. Histological examinations revealed that all of the polyps proliferated within the submucosa. Therefore, this type of polyp may be subject to endoscopic removal to enable a precise diagnosis and treatment.

A clinicopathologic study of small flat colorectal carcinoma

BACKGROUND

Recent studies have noted that small flat carcinomas do exist in the human colon, but their clinicopathologic features have not been fully delineated.

METHODS

A clinicopathologic study of 62 flat colorectal carcinomas (FCC) and 80 polypoid colorectal carcinomas (PCC) was performed. FCC were defined for the study as colorectal adenocarcinomas confined to the mucosa or submucosa, macroscopically characterized as slightly elevated, often nearly flat, and sometimes with central shallow depressions.

RESULTS

In intramucosal and submucosal invasive carcinomas, the mean size of FCCs was significantly smaller than that of PCCs, (P < 0.001). When compared with PCCs, FCCs were found more often in the proximal colon, less frequently well differentiated, and had fewer adenomatous remnants. In submucosal invasive cases, FCCs showed more frequent deep invasion (67 versus 32%, P < 0.05) and lymphovascular permeation (41% versus 16%, P < 0.05) compared with PCCs.

CONCLUSIONS

These results suggest that FCCs are characterized by frequent deep invasion with lymphovascular permeation even when small, and that they may be more prevalent away from the rectosigmoid area.

Effects of diet on experimentally induced intestinal ulcers in rats: morphology and tissue leukotrienes

The effects of dietary pretreatment on longitudinal ulcers of the intestine induced by indomethacin given intracolonically were investigated in rats. The rats were pretreated with either standard diet or liquid meals. Intracolonic indomethacin (24 mg/kg/day) given for two days produced longitudinal ulcers and small scattered ulcers in the small intestine in the control rats that were receiving standard pelleted formula. Three days pretreatment with one of two types of liquid meals, low residual diet (LRD) or elemental diet (ED), significantly reduced the incidence (3% in ED group and 0% in the LRD group) and the length of the longitudinal ulcers in the small intestine. The caecum was affected in each dietary pretreatment group (67% in controls, 80% in LRD group, and 69% in ED group). Colonic ulcers that were located in a longitudinal fashion were found in 42% of LRD group, while these ulcers were less frequently found in the ED group (13%) and controls (0%). Development of ulcers in the caecum and in the colon of rats in ED and LRD groups was more delayed than that of small intestinal ulcers of control rats. In another experiment, pretreatment by ED significantly increased colonic tissue leukotriene B4 concentration when compared with that of controls. These findings suggest that the site of experimental enteropathy induced by indomethacin given intracolonically can be modified by dietary pretreatment. This animal model can be available for investigating differences in the pathophysiology of enteropathy according to the site of involvement.

Gastrointestinal involvement in tuberous sclerosis. Two case reports

Two patients with tuberous sclerosis had multiple semispherical polyps in the large intestine, predominantly in the rectosigmoid colon. These were hamartomas with an excess of smooth muscle fibers in the stroma. In addition, the 21-year-old man had multiple tiny protrusions in the esophagus and oral fibroepithelial polyps. In the 31-year-old woman, who had pulmonary lymphangiomyomatosis with positive estrogen and progesterone receptors, hamartomatous gastric polyps, colonic leiomyoma, and adenomatous rectal polyps were also identified. Our findings suggest that gastrointestinal polyposis may be one of the phenotypes of tuberous sclerosis complex, possibly linking this disease with other hereditary polyposis syndromes.

Ossifying fibromyxoid tumor of soft parts: a morphological and immunohistochemical study

A case is presented of ossifying fibromyxoid tumor of soft parts (OFMTSP) which occurred in the left cheek of a 59 year old Chinese woman. Histologically, the tumor was located in the subcutis with a fibrous pseudocapsule that contained discontinuous rims of mature trabecular bone. The tumor cells were small, round to ovoid with a uniform, round nucleus and a pale or slightly eosinophilic cytoplasm. Most of the cells were arranged in a random manner, some in a vague lace-like pattern. Mitotic figures were extremely rare. The stroma appeared fibromyxoid with scattered foci of mucinous lakes. Immunohistochemically, most of the neoplastic cells displayed immunoreactivities for S-100 protein, S-100 protein alpha, vimentin and alpha-smooth muscle actin; many tumor cells were positive for desmin. The tumor also showed stromal immunoreactivity for type IV collagen and was negative for cytokeratins, epithelial membrane antigen, glial fibrillary acidic protein, neurofilaments, muscle-specific actin, Leu-7, myelin-basic protein, osteocalcin and melanoma-specific antigen. The immunophenotypes expressed by the present OFMTSP seem to reflect two lineages of neoplastic cell differentiation, that is of nerve sheath and of smooth muscle; at the present stage, it is premature to diagnose this lesion as either nerve sheath or smooth muscle tumor.

Mucosal prolapse syndrome: diagnosis with endoscopic US

PURPOSE

To determine the value of endoscopic ultrasound (US) in the diagnosis of mucosal prolapse syndrome (MPS), also known as solitary ulcer of the rectum.

MATERIALS AND METHODS

Three male and two female patients (age range, 17-66 years) with biopsy-proved MPS underwent endoscopic US. The average rectal wall thicknesses of the affected areas were compared with those of normal-appearing mucosa.

RESULTS

The gross appearance of the rectal lesions was classified into three types: polypoid (n = 2), flat (n = 1), and ulcerative (n = 2). In all three types of lesions, endoscopic US demonstrated smooth, diffuse thickening of the third layer of the rectal wall; the other layers had minimal thickening. Neither a solid hypoechoic mass nor a transmural infiltrating lesion was visible, and the five-layer structure of the rectal wall was completely preserved. In the polypoid lesions, the third layer was winding as well as thickened, and microcystic components were occasionally found.

CONCLUSION

Endoscopic US enabled differentiation of MPS from other conditions such as malignant neoplasia and Crohn disease.

Preventive effect of immunosuppressive agents against indomethacin-induced small intestinal ulcers in rats

The mechanism of nonsteroidal antiinflammatory drug-induced intestinal ulcers is not clearly understood. To evaluate whether immunosuppressants have a preventive effect against indomethacin-induced gastrointestinal damage, we investigated the effects of prednisolone, cyclosporin, and the newly developed immunosuppressant FK-506 in intracolonically indomethacin-treated rats: 24 mg/kg of indomethacin, administered intracolonically for two days, caused gastric ulcers and two types of small intestinal ulcers (longitudinal ulcers and scattered small ulcers). Pretreatment with intraperitoneal immunosuppressants reduced the size of gastric ulcers. Both cyclosporin (10 mg/kg) and FK-506 (1 mg/kg, 2 mg/kg) treatments significantly reduced the incidence and the length of the longitudinal ulcers of the small intestine when compared to the vehicle-treated controls, whereas prednisolone (20 mg/kg) did not show any preventive effect. Furthermore, the number of small scattered ulcers of the small intestine was significantly reduced by the high dose of FK-506 (2 mg/kg), but not by cyclosporin or prednisolone. These findings indicate that immunosuppressants have protective and antiinflammatory effects in indomethacin-induced gastroenteropathy, suggesting that cytokines may be important mediators in the pathogenesis of enteropathy induced by nonsteroidal antiinflammatory drugs.