[Long-term survival of a patient with advanced colon cancer and para-aortic lymph node metastases treated with re-administration of high-dose molecular targeted agent bevacizumab].

A 49-year-old woman was admitted to our hospital because of epigastralgia and abdominal distension. She was diagnosed as advanced colon cancer with para-aortic and common iliac lymph node metastases, without liver and lung metastasis. Extended right hemicolectomy was performed to remove symptoms of stenosis. Bevacizumab (BV) (5 mg/kg) + mFOLFOX6 was performed as the initial postoperative chemotherapy. The tumor marker CEA, CA19-9 decreased, and reduction in the size of distant lymph node metastasis was confirmed, which obtained PR. In July 2009, computed tomography revealed the right pulmonary hilar lymph node metastases and progressive disease was confirmed; therefore, cetuximab and FOLFIRI combination therapy was initiated. However, in October 2009, bilateral inguinal lymph node metastases was seen; therefore we changed chemotherapy to BV (10 mg/kg) and FOLFIRI. Although the abdominal lymph node was decreased slightly after 2 months, chemotherapy was changed to BV (10 mg/kg) and mFOLFOX6 since the inguinal lymph node had enlarged. Skin metastases appeared, and there was no change in the inguinal lymph node and abdominal lymph node. She was deceased due to peritonitis carcinomatosis; however, her survival time exceeded 30 months. There was a possibility that long-term survival could be obtained by increasing the quantity of BV and re-administering it in second-line chemotherapy after PD in BV + FOLFOX first-line chemotherapy.

Polaprezinc prevents ongoing thioacetamide-induced liver fibrosis in rats.

AIMS: Cirrhotic patients commonly have a liver zinc deficiency, which may aggravate liver fibrosis due to the lack of antioxidative effects of zinc. This study examined the ability of polaprezinc, N-(3-aminopropionyl)-l-histidinato zinc, to prevent fibrosis in a rat model of thioacetamide (TAA)-induced hepatic fibrosis. MAIN METHODS: Liver cirrhosis was induced by orally administering TAA for 20 weeks. The rats were cotreated with one of the following for the last 10 weeks of TAA treatment: (1) polaprezinc (50 or 200mg/kg/day); (2) l-carnosine (155 mg/kg/day), which contained equal amounts of l-carnosine as 200mg/kg/day polaprezinc; (3) zinc sulfate (112 mg/kg/day) or (4) zinc-l-aspartic complex (317.8 mg/kg/day). Both zinc supplementations contained equal amounts of zinc as high-dose polaprezinc. KEY FINDINGS: Hepatic zinc levels fell significantly in rats treated with TAA for 20 weeks. Cotreating with high-dose polaprezinc and zinc-l-aspartic complex for 10 weeks prevented hepatic zinc loss. Hepatic hydroxyproline and tissue inhibitor of metalloproteinases-1 (TIMP-1) were significantly higher in rats treated with TAA for 20 weeks than 10 weeks, whereas polaprezinc prevented changes in these fibrosis markers and reduced hepatic transforming growth factor-ß1 protein concentration, macroscopic and histologic changes. TAA caused oxidative stress-related changes in the liver that were prevented by high-dose polaprezinc and partially by zinc-l-aspartic complex. Treatment with l-carnosine, low-dose polaprezinc or zinc sulfate for 10 weeks did not affect liver fibrosis progression or oxidative stress-related changes. SIGNIFICANCE: Polaprezinc may prevent ongoing fibrosis by preventing zinc depletion, oxidative stress and fibrosis markers in cirrhotic livers.

Preventive effect of urinary trypsin inhibitor on the development of liver fibrosis in mice.

Urinary trypsin inhibitor (UTI) is a serine protease inhibitor produced in the liver that inhibits the production and activation of various cytokines, notably transforming growth factor-ß (TGF-ß), which are associated with the progression of liver fibrosis. However, the various roles of endogenous UTI in liver fibrosis have not been examined. This study, therefore, examined the long-term effects of UTI deficiency during both steady-state conditions and thioacetamide (TA)-induced liver fibrosis. Furthermore, the effects of continuous exogenous UTI administration were examined. Analyses of liver fibrosis marker, hyaluronic acid (HA), TGF-ß concentrations and histological findings at 30 weeks of age showed that homozygous UTI-knockout (KO) mice had higher HA and TGF-ß concentrations than did heterozygous UTI-KO mice and wild-type mice, although there was no histological evidence of liver fibrosis in these mice. TA treatment for 20 weeks also resulted in greater HA and TGF-ß levels in homozygous mice than in heterozygous and wild-type mice. Furthermore, homozygous mice had more severe liver fibrosis based on histological analyses. HA and TGF-ß levels were lower in homozygous UTI-KO mice that were continuously administered UTI versus those given distilled water. These findings indicate that UTI deficiency leads to the production of HA and hepatic TGF-ß and that administering exogenous UTI can ameliorate these changes. We conclude that endogenous UTI is produced in the liver to suppress the production and activation of TGF-ß and that administering exogenous UTI may be therapeutically beneficial for preventing liver fibrosis.

A new antimesenteric functional end-to-end handsewn anastomosis: surgical prevention of anastomotic recurrence in Crohn's disease.

BACKGROUND: Recurrence of Crohn's disease usually occurs at anastomotic sites. OBJECTIVE: A new anastomosis technique (Kono-S anastomosis) designed to minimize anastomotic restenosis was compared with conventional anastomoses. DESIGN AND SETTINGS: The Kono-S anastomosis technique was first used for Crohn's disease in 2003 at the Asahikawa Medical University Hospital. The resection is accomplished by transecting the bowel with a linear cutter so that the mesentery side is located in the center of the stump. Both stumps are sutured to create a supporting column to maintain the diameter and dimension of the anastomosis. Longitudinal enterotomies are made at the antimesenteric sides of the 2 segments of intestine. The side-to-side antimesenteric anastomosis is then performed in transverse fashion. The medical records and follow-up details of all patients undergoing this procedure were reviewed. PATIENTS: : From 2003 to 2009, 69 patients with Crohn's disease who underwent Kono-S anastomosis (group S) were compared with 73 historical patients with Crohn's disease who underwent conventional anastomosis (group C) from 1993 to 2003. MAIN OUTCOME MEASURES: A Kaplan-Meier analysis of the follow-up data on surgical recurrence at the anastomosis was performed. The endoscopic recurrence score at the anastomosis was calculated. RESULTS: The median endoscopic recurrence score in group S was significantly lower than that in group C (2.6 vs 3.4; P = .008). The Kaplan-Meier analysis showed a lesser probability of anastomotic surgical recurrence in the S group at 5 years (0% vs 15%; P = .0013). The absence of postoperative infliximab did not affect the restenosis rate in group S. LIMITATIONS: This study was limited by its historical retrospective nature. CONCLUSION: The Kono-S anastomosis appears to be effective in preventing anastomotic surgical recurrence in Crohn's disease.

Efficacy of goshajinkigan for peripheral neurotoxicity of oxaliplatin in patients with advanced or recurrent colorectal cancer.

Peripheral neurotoxicity is the major limiting factor for oxaliplatin therapy. Goshajinkigan (GJG), a traditional Japanese herbal medicine, was recently shown to be effective in protecting against the neurotoxicity of taxanes in Japan. We retrospectively investigated the effect of GJG on peripheral neurotoxicity associated with oxaliplatin therapy. Ninety patients with metastatic colorectal cancer that received FOLFOX4 or modified FOLFOX6 therapy were assigned to receive one of the following adjuncts: oral GJG at 7.5 g day(-1) (Group A, n = 11), intravenous supplementation of calcium gluconate and magnesium sulfate (1 g each before and after FOLFOX) (Group B, n = 14), combined GJG and calcium gluconate and magnesium sulfate therapies (Group C, n = 21), or no concomitant therapy (Group D, n = 44). The incidence of peripheral neurotoxicity was investigated when the cumulative dose of oxaliplatin exceeded 500 mg m(-2). When the cumulative dose of oxaliplatin exceeded 500 mg m(-2), the incidence of neuropathy (all grades) in Groups A-D was 50.0%, 100%, 78.9%, and 91.7%, respectively. It was lowest in the group that received GJG alone. Concomitant administration of GJG reduced the neurotoxicity of oxaliplatin in patients that received chemotherapy for colorectal cancer.

Anti-colitis and -adhesion effects of daikenchuto via endogenous adrenomedullin enhancement in Crohn's disease mouse model.

BACKGROUND AND AIMS: Adrenomedullin (ADM) is a member of the calcitonin family of regulatory peptides, and is reported to have anti-inflammatory effects in animal models of Crohn's disease (CD). We investigated the therapeutic effects of daikenchuto (DKT), an extracted Japanese herbal medicine, on the regulation of endogenous ADM in the gastrointestinal tract in a CD mouse model. METHODS: Colitis was induced in mice by intrarectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS); afterwards, DKT was given orally. Colonic damage was assessed on day 3 by macroscopic and microscopic observation, enzyme immunoassays of proinflammatory cytokines in the colonic mucosa, and serum amyloid A (SAA), a hepatic acute-phase protein. To determine the involvement of ADM, an ADM antagonist was instilled intrarectally before DKT administration. The effect of DKT on ADM production by intestinal epithelial cells was evaluated by enzyme immunoassay and real-time PCR. RESULTS: DKT significantly attenuated mucosal damage and colonic inflammatory adhesions, and inhibited elevations of SAA in plasma and the proinflammatory cytokines TNFα and IFNγ in the colon. Small and large intestinal epithelial cells produced higher levels of ADM after DKT stimulation. A DKT-treated IEC-6 cell line also showed enhanced ADM production at protein and mRNA levels. Abolition of this effect by pretreatment with an ADM antagonist shows that DKT appears to exert its anti-colitis effect via up-regulation of endogenous ADM in the intestinal tract. CONCLUSION: DKT exerts beneficial effects in a CD mouse model through endogenous release and production of ADM. Endogenous ADM may be a therapeutic target for CD.

Topical Application of Hangeshashinto (TJ-14) in the Treatment of Chemotherapy-Induced Oral Mucositis.

BACKGROUND: The optimal treatment of chemotherapy-induced oral mucositis is not well established. A recent study showed that hangeshashinto (TJ-14) might be useful for periodontal disease via downregulating pro-inflammatory prostaglandins in the cyclooxygenase pathway in human. Our study aimed to determine whether TJ-14 is effective in the management of chemotherapy-induced oral mucositis. METHODS: Fourteen patients afflicted with chemotherapy-induced oral mucositis during mFOLFOX6 or FOLFIRI treatment for metastasis of advanced colorectal cancer were randomly assigned to topical TJ-14 treatment thrice daily for 7 days. Patients prepared a 50 ml solution with 2.5 g of TJ-14 dissolved in tap water and rinsed their oral mucosa for more than 5 seconds and then expectorated it. TJ-14 was also topically applied with a cotton pellet on the mucosal lesions. The severity of oral mucositis was evaluated using the Common Terminology Criteria for Adverse Events version 4 before and after one-week TJ-14 treatment. RESULTS: After the one-week topical treatment with TJ-14, thirteen of the fourteen patients (92.8 %) showed improvements in oral mucositis, with significantly decreased mean CTCAE grades (P = 0.0012). Compared to baseline, none of the patients' CTCAE grades worsened. The compliance of TJ-14-treatment was good and side effects from TJ-14 were not observed. CONCLUSIONS: Topical application of TJ-14 may have therapeutic effects in patients with chemotherapy-induced oral mucositis via downregulation of pro-inflammatory prostaglandins. A prospective, randomized, controlled, double-blind studies are necessary to confirm the findings of this open-label, pilot study.

Cetuximab-induced hypomagnesaemia aggravates peripheral sensory neurotoxicity caused by oxaliplatin.

Calcium and magnesium replacement is effective in reducing oxaliplatin-induced neurotoxicity. However, cetuximab treatment has been associated with severe hypomagnesaemia. Therefore, we retrospectively investigated whether cetuximab-induced hypomagnesaemia exacerbated oxaliplatin-induced neurotoxicity. Six patients with metastatic colorectal cancer who were previously treated with oxaliplatin-fluorouracil combination therapy were administered cetuximab in combination with irinotecan alone or irinotecan and fluorouracil as a second-line treatment. All patients had normal magnesium levels before receiving cetuximab. The Common Terminology Criteria for Adverse Events version 3.0 was used to evaluate the grade of neurotoxicity, hypomagnesaemia, hypocalcaemia, and hypokalemia every week. All six patients had grade 1 or higher hypomagnesaemia after starting cetuximab therapy. The serum calcium and potassium levels were within the normal range at the onset of hypomagnesaemia. Oxaliplatin-induced neurotoxicity occurred in all patients at the beginning of cetuximab therapy, with grade 1 neurotoxicity in five patients and grade 2 in one patient. After cetuximab administration, the neurotoxicity worsened in all six patients, and three progressed to grade 3. Among the three patients with grade 3 neurotoxicity, two required a dose reduction and one had to discontinue cetuximab therapy. A discontinuation or dose reduction in cetuximab therapy was associated with exacerbated oxaliplatin-induced neurotoxicity due to cetuximab-induced hypomagnesaemia in half of patients who had previously received oxaliplatin. Therefore, when administering cetuximab after oxaliplatin therapy, we suggest serially evaluating serum magnesium levels and neurotoxicity.

[Survey of oxaliplatin-associated peripheral sensory neuropathy using an interview-based questionnaire in patients with advanced colorectal cancer].

In performing FOLFOX chemotherapy (infusional 5-FU/LV with oxaliplatin) for advanced colorectal cancer, the neurotoxicity of oxaliplatin (L-OHP) is the dose-limiting factor. A retrospective study of 25 consecutive patients, receiving modified FOLFOX6 (mFOLFOX6) for advanced colorectal cancer, was conducted. From March 2006 to February 2008, we investigated the process of development of sensory neuropathy by adverse effect grading and our original interview-based intake about the afflicted regions. Neurotoxicity developed in 21 cases (84%) after 6 courses and the cumulative L-OHP dose was 410 mg/m(2) in median. In 11 cases (52%), it developed from the fingers, while in 8 cases (38%), it occurred from the fingers and toes simultaneously. It developed from the toes or tongue only in one case each. In 6 cases (55%), in which it occurred from the fingers, the symptom aggravated to grade 2 (G2) according to the Neurotoxicity Criteria of DEBIOPHARM (DEBNTC). On the other hand, in cases of coexpression of the fingers and toes, 7 cases (88%) developed G2 neuropathy, among one of whom suffered from grade 3 (G3). The coexistence of diabetes mellitus without neuropathy had no influence on the development of the neurotoxicity in the grading of DEB-NTC. One month after the last mFOLFOX6 therapy, neurotoxicity newly developed in one case, and was aggravated in two cases two months after cessation of the chemotherapy. Therefore, careful observation of the course should be continued even after the end of mFOLFOX6 therapy. Our results suggest that L-OHP neurotoxicity develops on fingers or fingers and toes simultaneously in most cases. And when it occurred on fingers and toes simultaneously, it would aggravate to G2 or G3 during the chemotherapy. The interviewed-based intake about the afflicted region, such as ours, can be used to predict the deterioration of the neurotoxicity.

Colonic vascular conductance increased by Daikenchuto via calcitonin gene-related peptide and receptor-activity modifying protein 1.

BACKGROUND: Daikencyuto (DKT) is a traditional Japanese medicine (Kampo) and is a mixture of extract powders from dried Japanese pepper, processed ginger, ginseng radix, and maltose powder and has been used as the treatment of paralytic ileus. DKT may increase gastrointestinal motility by an up-regulation of the calcitonin gene-related peptide (CGRP). CGRP is also the most powerful vasoactive substance. In the present study, we investigated whether DKT has any effect on the colonic blood flow in rats. MATERIALS AND METHODS: Experiments were performed on fasted anesthetized and artificially ventilated Wistar rats. Systemic mean arterial blood pressure and heart rate were recorded. Red blood cell flux in colonic blood flow was measured using noncontact laser tissue blood flowmetry, and colonic vascular conductance (CVC) was calculated as the ratio of flux to mean arterial blood pressure. We examined four key physiological mechanisms underlying the response using blocker drugs: CGRP1 receptor blocker (CGRP(8-37)), nitric oxide synthase inhibitor, vasoactive intestinal polypeptide (VIP) receptor blocker ([4-Cl-DPhe6, Leu17]-VIP), and substance P receptor blocker (spantide). Reverse transcription-polymerase chain reaction was used for the detection of mRNA of calcitonin receptor-like receptor, receptor-activity modifying protein 1, the component of CGRP 1 receptor and CGRP. After laparotomy, a cannula was inserted into the proximal colon to administer the DKT and to measure CVC at the distal colon. RESULTS: Intracolonal administration of DKT (10, 100, and 300 mg/kg) increased CVC (basal CVC, 0.10 mL/mmHg) from the first 15-min observation period (0.14, 0.17, and 0.17 mL/mmHg, respectively) and with peak response at either 45 min (0.17 mL/mmHg by 10 mg/kg), or 75 and 60 min (0.23 and 0.21 mL/mmHg by 100 and 300 mg/kg, respectively). CGRP(8-37) completely abolished the DKT-induced hyperemia, whereas nitric oxide synthase inhibitor partially attenuated the DKT-induced hyperemia. [4-Cl-DPhe6, Leu17]-VIP and spantide did not affect the hyperemia. Japanese pepper significantly increased CVC at 45 min or later, whereas ginseng radix only showed a significant increase at 15 min. Reverse transcription-polymerase chain reaction showed that mRNA for calcitonin receptor-like receptor, receptor-activity modifying protein 1, and CGRP were expressed in rat colon and up-regulated by DKT. CONCLUSIONS: The present study demonstrated that DKT increased CVC, which was mainly mediated by CGRP and its receptor components.

[A case of neurotoxicity reduced with goshajinkigan in modified FOLFOX6 chemotherapy for advanced colon cancer].

In performing FOLFOX (infusional 5-FU/LV with oxaliplatin) for advanced colorectal cancer, neurotoxicity of oxaliplatin (L-OHP) is the serious dose limiting factor. On the other hand, goshajinkigan is recently considered as an effective agent for the neurotoxicity of taxanes in Japan. We have applied goshajinkigan (TJ 107) for a case of advanced colon cancer with mFOLFOX 6, and experienced a reduction in numbness, the adverse effect of LOHP. A 57-year-old woman with descending colon cancer (H 1, P 3, Stage IV) underwent hemicolectomy D 2, rt.colectomy, bilateral oophorectomy, cholecystectomy and transverse colonostomy. After operation, mFOLFOX 6 was applied. In order to reduce the neurotoxicity of L-OHP, TJ 107 was used together from the third course. The severities of neurotoxicity before and after administration of TJ 107 were grade 2 and 1,respectively. TJ 107 could reduce or prevent the neurotoxicity of L-OHP.

Acute rhabdomyolysis of the soleus muscle induced by a lightning strike: magnetic resonance and scintigraphic findings.

Among natural disasters, a lightning strike is a rare but potentially life-threatening phenomenon. If victims survive a cardiac arrest due to instantaneous passage of an exceptionally high voltage electric charge through the whole body, they may be afflicted with various complications such as muscle necrosis resulting in acute renal failure. In this article, we report a case of a 54-year-old man with acute rhabdomyolysis of the left soleus muscle associated with a lightning strike. T2-weighted and short-tau inversion recovery MR images showed a high signal intensity in the left soleus muscle. A whole-body bone scintigram showed abnormal uptakes in the left soleus muscle and the dorsal aspect of the left foot. MR and scintigraphic evaluations were very useful in depicting the site and extent of muscle damage. Since the patient showed a surprisingly high level of serum creatine kinase, the added information was very valuable for determining the patient's management.

Direct evidence that induced nitric oxide production in hepatocytes prevents liver damage during lipopolysaccharide tolerance in rats.

BACKGROUND: The role of nitric oxide (NO) in lipopolysaccharide (LPS) tolerance in the liver has been investigated in a number of previous studies, but it is still not clear whether NO is cytotoxic or cytoprotective. The aims of this study were to investigate whether low-dose LPS (LLPS)-induced hepatic production of NO is beneficial and to clarify the origins of cytoprotective NO-producing cells in the liver during LPS tolerance. MATERIALS AND METHODS: Male Wistar rats received saline or LLPS intraperitoneally (i.p.; 0.01-1000 microg/kg) followed by a high dose of LPS (HLPS, 5 mg/kg) at various time intervals (4-16 h). NG-nitro-L-arginine methyl ester (L-NAME) was used to investigate the effects of inhibition of NOS. 4,5-Diaminofluorescein (DAF-2) was used to identify NO-producing cells in isolated liver cells in vitro. At various time points (4-16 h) after saline or LLPS (1 microg/kg, i.p.) injection, hepatocytes and Kupffer cells were isolated, incubated in 7 microm DAF-2 diacetate, and perfused with Krebs solution. Illumination at 495 nm revealed DAF-fluorescence (515 nm) in isolated cells under confocal laser fluorescence microscopy. The NO production in hepatocytes and Kupffer cells was assessed by the number of labeled cells per 1000 cells or per 100 cells, respectively. RESULTS: Pretreatment with LLPS (0.1-100 microg/kg) resulted in a significant reduction (maximal at 8 h) of the HLPS-induced liver damage. L-NAME abolished the LLPS-induced protection. The NO production in hepatocytes was significantly increased and reached a maximum of 84% of all cells 8 h after LLPS administration. By contrast, the NO production in Kupffer cells remained constant at 95%, even following preinjection of LLPS. CONCLUSION: LLPS-induced NO in hepatocytes, but not in Kupffer cells, exhibits cytoprotective effects on HLPS-induced liver damage, suggesting that NO has a beneficial role in the induction of the early phase of LPS tolerance.

Successful low-dose chemotherapy using vinblastine and methotrexate for the treatment of an ileoanal pouch mesenteric desmoid tumor: report of a case.

The purpose of this report was to describe the first known case of ileoanal pouch salvage by a low-dose regimen of vinblastine and methotrexate chemotherapy for the treatment of desmoid tumor arising from the mesentery of the ileoanal pouch in a patient who had undergone ileal pouch-anal anastomosis for familial adenomatous polyposis. Mesenteric desmoid tumor involving the ileoanal pouch in a 28-year-old female was treated with vinblastine and methotrexate biweekly for 12 months and monthly for 12 months in an outpatient unit. The desmoid tumor response to the treatment was assessed at routine intervals by physical examination and magnetic resonance imaging. Desmoid tumor was successfully treated with a low-dose regimen of vinblastine and methotrexate chemotherapy without significant side effects, and function of the ileoanal pouch was fully preserved. Magnetic resonance imaging showed a decrease in desmoid tumor size and cellularity, and changes consistent with fibrosis. This is a unique case highlighting the possibility of ileoanal pouch salvage by low-dose combination chemotherapy using vinblastine and methotrexate in a familial adenomatous polyposis patient with mesenteric desmoid tumor.

Impaired nitric oxide production of the myenteric plexus in colitis detected by a new bioimaging system.

Direct measurement of the release of nitric oxide (NO) from the myenteric plexus has been extremely difficult to date, due to the lack of suitable methodologies. We have developed a new bioimaging system to visualize the nitrergic neurons of the myenteric plexus and investigated whether NO production is impaired in dextran sulfate sodium (DSS)-induced colitis. Longitudinal muscle layers with the myenteric plexus intact were obtained from the rat colon and were incubated with 4,5-diaminofluorescein-2-diacetate (DAF-2DA) (7 microm) for 30 min. Illumination at 450-490 nm revealed the fluorescence in the myenteric plexus. Confocal laser microscopy and three-dimensional reconstruction techniques were used to quantify the changes in the amount of NO production by the myenteric plexus. Fluorescent double-labeled immunostaining for nNOS was performed to confirm the colocalization of nNOS in 4,5-diaminofluorescein (DAF-2)-positive cells. DAF-2 fluorescence was abolished by pretreatment with N(G)-nitro-l-arginine methyl ester (l-NAME; a nonselective NOS inhibitor), 1-(2-trifluoromethylphenyl) imidazole (TRIM; a selective neuronal NOS inhibitor), and omega-conotoxin GVIA (an N-type Ca(2+) channel blocker), but not by nifedipine (an l-type Ca(2+) channel blocker). Fluorescent double-labeled immunostaining showed that DAF-2-positive cells colocalized with nNOS-positive cells. Oral administration of 5% DSS for 7 days induced distal colitis and the number of DAF-2-positive neurons were significantly reduced to 55 +/- 17% of control. DAF-2 offers a sensitive indicator for visualizing production of NO with high spatial resolution. This new system may contribute to the study of the pathophysiological role of the nitrergic pathway in the gastrointestinal tract.

Acetic acid-derived prostaglandin-dependent colonic adaptive cytoprotection is preserved in chronic colitis: role of cyclo-oxygenase.

BACKGROUND AND AIMS: We recently reported the phenomenon of prostaglandin-dependent colonic adaptive cytoprotection (CAP) against acute colonic injury induced by acetic acid (AA) in the normal colon. This study investigated whether the CAP is preserved in the chronic inflamed colon. MATERIALS AND METHODS: Normal rats and a chronic colitis model, induced by trinitrobenzene sulfonic acid, received an intracolonal administration (0.5 ml) of saline or AA at low concentration (1%) followed by high concentration (8%) 30 min later. The distal colon was removed 48 h after 8% AA administration, and colitis was assessed by macroscopic scoring and measurement of the myeloperoxidase (MPO) activity. Indomethacin (5 mg/kg), a nonselective cyclo-oxygenase (COX) inhibitor, or N-[2-cyclohexyloxy-4-nitrophenyl] methane-sulfonamide (NS398, 1 mg/kg), a COX type 2 selective inhibitor, was injected intraperitoneally 1 h before pretreatment with 1% AA. RESULTS: Intracolonal administration of 8% AA induced colonic mucosal damage (macroscopic score 10.0+/-0.9) and elevated MPO activity (2.8+/-0.2 U/g), which were significantly reduced to 3.3+/-0.8 and 1.8+/-0.2 U/g by 1% AA pretreatment, respectively. Indomethacin abolished the gross mucosal protective effect by 1% AA pretreatment in 8% AA-derived colitis in normal rats while the NS398 had no effect. Both indomethacin and NS398 reversed the MPO activity reduction induced by 1% AA pretreatment. In chronic inflamed colon 8% AA treatment resulted in an increase in the macroscopic score to 11.5+/-0.4 from 4.7+/-0.4, but not the MPO activity, which was significantly reduced to 5.7+/-0.9 by 1% AA pretreatment. This gross mucosal protective effect by 1% AA pretreatment in chronic inflamed colon was reversed by indomethacin while the NS398 had no effect. CONCLUSION: These data show that COX-1 and COX-2 derived prostaglandins induced by low concentration AA pretreatment reduce the colonic mucosal injury and the increase in the MPO activity in colitis, respectively. The protective effect of COX-1 is preserved in chronic inflamed colon. These findings support the existence of a low concentration of AA-derived prostaglandin-dependent CAP and suggest that colonic AA, which is derived from bacterial breakdown of carbohydrate and protein in the colon, plays a crucial role in the endogenous defense mechanisms.