Caspase-1 inhibition alleviates acute renal injury in rats with severe acute pancreatitis.

AIM: To assess the effect of inhibition of caspase-1 on acute renal injury in rats with severe acute pancreatitis (SAP). METHODS: Forty-two Sprague-Dawley rats were randomly divided into three groups: healthy controls (HC, n = 6), SAP rats treated with saline (SAP-S, n = 18), or SAP rats treated with a caspase-1/interleukin (IL)-1ß-converting-enzyme (ICE) inhibitor (SAP-I-ICE, n = 18). SAP was induced by retrograde infusion of 5% sodium taurocholate into the bile-pancreatic duct. HC rats were subjected to identical treatment and surgical procedures without sodium taurocholate. Rats received an intraperitoneal injection of isotonic saline (SAP-S) or the inhibitor (SAP-ICE-I) at 2 and 12 h after induction of acute pancreatitis. Surviving rats were sacrificed at different time points after SAP induction; all samples were obtained and stored for subsequent analyses. The levels of blood urea nitrogen (BUN) and creatinine (Cr) were measured using automatic methods, and serum IL-1ß concentrations were measured by an enzyme-linked immunosorbent assay. Intrarenal expression of IL-1ß, IL-18 and caspase-1 mRNAs was detected by RT-PCR. IL-1ß protein expression and the pathologic changes in kidney tissues were observed by microscopy after immunohistochemical or hematoxylin and eosin staining, respectively. RESULTS: The serum levels of BUN and Cr in the SAP-S group were 12.48 ± 2.30 mmol/L and 82.83 ± 13.89 µmol/L at 6 h, 23.53 ± 2.58 mmol/L and 123.67 ± 17.67 µmol/L at 12 h, and 23.60 ± 3.33 mmol/L and 125.33 ± 21.09 µmol/L at 18 h, respectively. All were significantly increased compared to HC rats (P < 0.01 for all). Levels in SAP-ICE-I rats were significantly decreased compared to SAP-S rats both at 12 and 18 h (P < 0.01 for all). Serum IL-1ß levels in the SAP-S group were 276.77 ± 44.92 pg/mL at 6 h, 308.99 ± 34.95 pg/mL at 12 h, and 311.60 ± 46.51 pg/mL at 18 h; all significantly higher than those in the HC and SAP-ICE-I groups (P < 0.01 for all). Intrarenal expression of IL-1ß mRNA was weak in HC rats, but increased significantly in SAP-S rats (P < 0.01). ICE inhibition significantly decreased the expression of IL-1ß and IL-18 mRNAs (P < 0.05 for all vs SAP-S), whereas caspase-1 mRNA expression was not significantly different. Weak IL-1ß immunostaining was observed in HC animals, and marked staining was found in the SAP-S group mainly in renal tubular epithelial cells. IL-1ß immunostaining was significantly descended in SAP-ICE-I rats compared to SAP-S rats (P < 0.05). Caspase-1 inhibition had no effect on the severity of kidney tissue destruction. CONCLUSION: The expression of caspase-1-activated cytokines IL-1ß and IL-18 plays a pivotal role in acute renal injury in rats with experimental SAP. Caspase-1 inhibition improves renal function effectively.

Endoplasmic reticulum stress is involved in hepatic SREBP-1c activation and lipid accumulation in fructose-fed mice.

A link between fructose drinking and nonalcoholic fatty liver disease (NAFLD) has been demonstrated in human and rodent animals. The aim of the present study was to investigate whether endoplasmic reticulum (ER) stress is mediated in the development of fructose-induced NAFLD. Female CD-1 mice were fed with 30% fructose solution for eight weeks. Hepatic lipid accumulation was assessed. Hepatic nuclear sterol regulatory element-binding protein (SREBP)-1c was measured. Results showed that hepatic SREBP-1c was activated in mice fed with fructose solution. Fatty acid synthase (fas) and acetyl-CoA carboxylase (acc), two target genes of SREBP-1c, were up-regulated. Fructose-evoked hepatic SREBP-1c activation seemed to be associated with insulin-induced gene (Insig)-1 depletion. An ER stress and unfolded protein response (UPR), as determined by an increased glucose-regulated protein (GRP78) expression and an increased eIF2α and PERK phosphorylation, were observed in liver of mice fed with fructose solution. Phenylbutyric acid (PBA), an ER chemical chaperone, not only significantly attenuated ER stress, but also alleviated fructose-induced hepatic Insig-1 depletion. PBA inhibited fructose-evoked hepatic SREBP-1c activation and the expression of SREBP-1c target genes, and protected against hepatic lipid accumulation. In conclusion, ER stress contributes, at least in part, to hepatic SREBP-1c activation and lipid accumulation in fructose-evoked NAFLD.

Melatonin alleviates lipopolysaccharide-induced hepatic SREBP-1c activation and lipid accumulation in mice.

A link between endotoxemia and nonalcoholic fatty liver disease (NAFLD) has been demonstrated in human and rodent animals. Nevertheless, the molecular mechanisms of endotoxin-evoked NAFLD remain poorly understood. We hypothesize that reactive oxygen species (ROS) mediate lipopolysaccharide (LPS)-evoked hepatic lipid accumulation. Melatonin is an antioxidant. In the present study, we investigated the effects of melatonin on LPS-induced hepatic lipid accumulation. We showed that a single dose of LPS significantly increased hepatic triglyceride (TG) contents and caused hepatic lipid accumulation in mice. Further analysis found that hepatic sterol regulatory element-binding protein (SREBP)-1c was activated in LPS-treated mice. In agreement with hepatic SREBP-1c activation, fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), two SREBP-1c target genes, were significantly upregulated in liver of mice injected with LPS. Melatonin significantly attenuated LPS-induced SREBP-1c activation and the expression of SREBP-1c target genes. In addition, melatonin reduced serum and hepatic triglyceride (TG) content and prevented LPS-induced hepatic lipid accumulation. Taken together, these results suggest that ROS might be, at least partially, mediated in LPS-induced SREBP-1c activation and hepatic lipid accumulation. Melatonin may be useful as pharmacological agents to protect against endotoxin-evoked NAFLD.

Klippel-Trenaunay syndrome with gastrointestinal bleeding, splenic hemangiomas and left inferior vena cava.

Klippel-Trenaunay syndrome is a congenital vascular anomaly characterized by a triad of varicose veins, cutaneous capillary malformation, and hypertrophy of bone and (or) soft tissue. Gastrointestinal vascular malformations in Klippel-Trenaunay syndrome may present with gastrointestinal bleeding. The majority of patients with splenic hemangiomatosis and/or left inferior vena cava are asymptomatic. We herein report a case admitted to the gastroenterology clinic with life-threatening hematochezia and symptomatic iron deficiency anemia. Due to the asymptomatic mild intermittent hematochezia, splenic hemangiomas and left inferior vena cava, the patient did not seek any help for gastrointestinal bleeding until his admittance to our department for evaluation of massive gastrointestinal bleeding. He was referred to angiography because of his serious pathogenetic condition and inefficiency of medical therapy. The method showed that hemostasis was successfully achieved in the hemorrhage site by embolism of corresponding vessels. Further endoscopy revealed vascular malformations starting from the stomach to the descending colon. On the other hand, computed tomography revealed splenic hemangiomas and left inferior vena cava. To the best of our knowledge, this is the first Klippel-Trenaunay syndrome case presenting with gastrointestinal bleeding, splenic hemangiomas and left inferior vena cava. The literature on the evaluation and management of this case is reviewed.

Involvement of 90-kuD ribosomal S6 kinase in collagen type I expression in rat hepatic fibrosis.

AIM: To investigate the relationship between 90-kuD ribosomal S6 kinase (p90RSK) and collagen type I expression during the development of hepatic fibrosis in vivo and in vitro. METHODS: Rat hepatic fibrosis was induced by intraperitoneal injection of dimethylnitrosamine. The protein expression and cell location of p90RSK and their relationship with collagen type I were determined by co-immunofluoresence and confocal microscopy. Subsequently, RNAi strategy was employed to silence p90RSK mRNA expression in HSC-T6, an activated hepatic stellate cell (HSC) line. The expression of collagen type I in HSC-T6 cells was assessed by Western blotting and real-time polymerase chain reaction. Furthermore, HSCs were transfected with expression vectors or RNAi constructs of p90RSK to increase or decrease the p90RSK expression, then collagen type I promoter activity in the transfected HSCs was examined by reporter assay. Lastly HSC-T6 cells transfected with p90RSK siRNA was treated with or without platelet-derived growth factor (PDGF)-BB at a final concentration of 20 microg/L and the cell growth was determined by MTS conversion. RESULTS: In fibrotic liver tissues, p90RSK was over-expressed in activated HSCs and had a significant positive correlation with collagen type I levels. In HSC-T6 cells transfected with RNAi targeted to p90RSK, the expression of collagen type I was down-regulated (61.8% in mRNA, P < 0.01, 89.1% in protein, P < 0.01). However, collagen type I promoter activity was not increased with over-expression of p90RSK and not decreased with low expression either, compared with controls in the same cell line (P = 0.076). Furthermore, p90RSK siRNA exerted the inhibition of HSC proliferation, and also abolished the effect of PDGF on the HSC proliferation. CONCLUSION: p90RSK is over-expressed in activated HSCs and involved in regulating the abnormal expression of collagen type I through initiating the proliferation of HSCs.

Detection of RASSF1A promoter hypermethylation in serum from gastric and colorectal adenocarcinoma patients.

AIM: To evaluate the diagnostic role of serum RASSF1A promoter hypermethylation in gastric and colorectal adenocarcinoma. METHODS: Methylation-specific polymerase chain reaction (MSPCR) was used to examine the promoter methylation status of the serum RASSF1A gene in 47 gastric adenocarcinoma patients, 45 colorectal adenocarcinoma patients, 60 patients with benign gastrointestinal disease (30 with benign gastric disease and 30 with benign colorectal disease), and 30 healthy donor controls. A paired study of RASSF1A promoter methylation status in primary tumor, adjacent normal tissue, and postoperative serum were conducted in 25 gastric and colorectal adenocarcinoma patients who later were underwent surgical therapy. RESULTS: The frequencies of detection of serum RASSF1A promoter hypermethylation in gastric (34.0%) and colorectal (28.9%) adenocarcinoma patients were significantly higher than those in patients with benign gastric (3.3%) or colorectal (6.7%) disease or in healthy donors (0%) (P < 0.01). The methylation status of RASSF1A promoter in serum samples was consistent with that in paired primary tumors, and the MSPCR results for RASSF1A promoter methylation status in paired preoperative samples were consistent with those in postoperative serum samples. The serum RASSF1A promoter hypermethylation did not correlate with patient sex, age, tumor differentiation grade, surgical therapy, or serum carcinoembryonic antigen level. Although the serum RASSF1A promoter hypermethylation frequency tended to be higher in patients with distant metastases, there was no correlation between methylation status and metastasis. CONCLUSION: Aberrant CpG island methylation within the promoter region of RASSF1A is a promising biomarker for gastric and colorectal cancer.

Interleukin-18: a pro-inflammatory cytokine that plays an important role in acute pancreatitis.

A large body of clinical and experimental evidence suggests that cytokines play a key role in the pathogenesis of local and systemic complications of acute pancreatitis. IL-18 is a pro-inflammatory cytokine that plays a key role in many human diseases, including acute pancreatitis. This review focuses on the present understanding in IL-18 and its potential role in acute pancreatitis. IL-18 levels reflect the severity of acute pancreatitis and display a significant negative correlation with the concentrations of antioxidative damage factors, serum selenium and glutathione peroxidases (GPx). The relationship between IL-18 and other pro-inflammatory cytokines shows that IL-18 is one of the key mediators of inflammation in the pathogenesis of acute pancreatitis. Elevation of serum IL-18 levels may mediate acute pancreatitis associated liver injury. The use of IL-18 antagonists as direct routes to block IL-18 activity and P2X7 receptor antagonists and interleukin-1beta-converting enzyme (ICE) inhibitors as indirect routes to block IL-18 activity suggest that specific therapeutic inhibition of IL-18 is a promising therapeutic approach for acute pancreatitis.

Therapeutic effects of caspase-1 inhibitors on acute lung injury in experimental severe acute pancreatitis.

AIM: To assess the therapeutic effect of Caspase-1 inhibitors (ICE-I) on acute lung injury (ALI) in experimental severe acute pancreatitis (SAP). METHODS: Forty-two SD rats were randomly divided into 3 groups: healthy controls (HC, n = 6); SAP-S group (n = 18); SAP-ICE-I group (n = 18). SAP was induced by retrograde infusion of 5% sodium taurocholate into the bile-pancreatic duct. HC rats underwent the same surgical procedures and duct cannulation without sodium taurocholate infusion. In SAP-S group, rats received the first intraperitoneal injection of isotonic saline 2 h after induction of acute pancreatitis and a repeated injection after 12 h. In SAP-ICE-I group, the rats were firstly given ICE inhibitors intraperitoneally 2 h after induction of pancreatitis. As in SAP-S group, the injection was repeated at 12 h. Serum IL-1beta was measured by ELISA. Intrapulmonary expression of Caspase-1, IL-1beta and IL-18 mRNA were detected by semi-quantitative RT-PCR. The wet/dry weight ratios and histopathological changes of the lungs were also evaluated. RESULTS: Serum IL-1beta levels in SAP-S group were 276.77 +/- 44.92 pg/mL at 6 h, 308.99 +/- 34.95 pg/mL at 12 h, and 311.60 +/- 46.51 pg/mL at 18 h, which were increased significantly (P < 0.01, vs HC). In SAP-ICE-I group, those values were decreased significantly (P < 0.01, vs SAP-S). Intrapulmonary expression of Caspase-1, IL-1beta and IL-18 mRNA were observed in the HC group, while they were increased significantly in the SAP-S group (P < 0.01, vs HC). The expression of IL-1beta and IL-18 mRNA were decreased significantly in the SAP-ICE-I group (P < 0.01, vs SAP-S), whereas Caspase-1 mRNA expression had no significant difference (P > 0.05). The wet/dry weight ratios of the lungs in the SAP-S group were increased significantly (P < 0.05 at 6 h, P < 0.01 at 12 h and 18 h, vs HC) and they were decreased significantly in the SAP-ICE-I group (P < 0.05, vs SAP-S). Caspase-1 inhibitors ameliorated the severity of ALI in SAP. CONCLUSION: Caspase-1 activation, and overproduction of IL-1beta and IL-18 play an important role in the course of ALI, and Caspase-1 inhibition is effective for the treatment of ALI in experimental SAP.

Effects of recombinant human canstatin protein in the treatment of pancreatic cancer.

AIM: To examine the effect of canstatin, a newly discovered endogenous inhibitor of angiogenesis, in the treatment of pancreatic cancer in vivo. METHODS: The canstatin cDNA fragment was synthesized and amplified from the total RNA extracted from human placenta tissues by RT-PCR. The resulting product was firstly cloned into pUCm-T vector, then into plasmid pET-22b (+) and transformed into E. coli BL21. Isopropyl-1-thio-b-Dgalactopyran-oside (IPTG) was used to induce the expression of canstatin protein and affinity chromatography was used to purify the protein. To determine the activity of purified recombinant human canstatin (rhCanstatin), orthotopic xenograft human pancreatic cancer models were established. Human pancreatic cancer cells (SW1990) were injected into the pancreas of BALB/c nude mice. Twenty-four nude mice with orthotopic xenograft tumor were randomly divided into 3 groups 10 d after the inoculation, and were treated with PBS 0.3 mL, or canstatin 5 mg/kg, or 10 mg/kg per day for 3 wk intraperitoneally. When the experiment was over, all tumors were resected and the effects of rhCanstatin on tumor growth, microvessel density (MVD) were analyzed. RESULTS: After IPTG induction, SDS-PAGE showed a new monomeric 24 kDa protein band. This protein was purified through affinity chromatography and refolded through dialysis with a final concentration of 60 mg/L. In orthotopic pancreatic cancer models, the final tumor volume in groups treated with PBS, canstatin 5 mg/kg, 10 mg/kg were 355.21+/-39.54 mm3, 112.73+/-10.47 mm3, and 61.75+/-6.99 mm3 respectively. The immunohistochemical examination showed that the MVD in tumors treated with canstatin was significantly less than that in other group. CONCLUSION: These findings demonstrate that the rhCanstatin effectively retards the growth of pancreatic cancer in a dose-dependent manner through inhibiting angiogenesis and may be a promising therapeutic agent for pancreatic cancer treatment in the clinic.

Expression of gamma-aminobutyric acid and glutamic acid decarboxylases in rat descending colon and their relation to epithelial differentiation.

OBJECTIVE: To detect the expression of gamma-aminobutyric acid (GABA) and glutamic acid decarboxylases (GADs; including two isoforms GAD65 and GAD67) in the epithelial growth zones of the descending colon in rats, and to investigate their relation to epithelial differentiation and proliferation. METHODS: The expression of GABA and GADs in rat descending colon was investigated by immunofluorescent staining and confocal laser scanning techniques, and goblet cells were further investigated by wheat-germ agglutinin histochemistry. In addition, GAD65 and GAD67 mRNAs were also detected by reverse transcription-polymerase chain reaction. Furthermore, evaluation of cell kinetics in colonic epithelia was conducted by ABC immunostaining using a monoclonal antibody against proliferating cell nuclear antigen (PCNA). RESULTS: Immunoreactive GABA and GADs were distributed in the upper third of the crypts and at the luminal surface in the rat descending colon. Strong staining for GABA and GADs was localized mainly in the cytoplasm of epithelial cells near the neck of the crypts and along the luminal surface. In addition, GABA and GAD65 were also detected at the lamina propria in colonic mucosa. No staining for GABA or GADs was found in goblet cells. GAD65 and GAD67 mRNAs were identified in homogenates of rat descending colon. PCNA labeled nuclei were found in the lower two-thirds of the crypts. CONCLUSIONS: The expression of GABA and GADs in the maturation and function zones of rat descending colon suggests that GABA may be involved in the differentiation of colonic epithelial cells.

Characteristic expression of gamma-aminobutyric acid and glutamate decarboxylase in rat jejunum and its relation to differentiation of epithelial cells.

AIM: To investigate the expression between gamma-aminobutyric acid (GABA) and glutamate decarboxylase and its relation with differentiation and maturation of jejunal epithelial cells in rat jejunum. METHODS: Immunohistochemical expression of GABA and glutamate decarboxylase (GAD, including two isoforms, GAD65 and GAD67) was investigated in rat jejunum. Meanwhile, double staining was performed with GAD65 immunohistochemistry, followed by lectin histochemistry of fluorescent wheat germ agglutinin. Furthermore, evaluation of cell kinetics in jejunum was conducted by (3)H-thymidine autoradiography and immunohistochemistry using a monoclonal antibody to proliferating cell nuclear antigen (PCNA). RESULTS: The cells showing positive immunoreactivity GABA and GAD65 were mainly distributed in the villi in rat jejunum, while jejunal epithelial cells were negative for GAD67. Positive GABA or GAD65 staining was mainly located in the cytoplasm and along the brush border of epithelial cells in the middle and upper portions. In addition, a few GABA and GAD65 strongly positive cells were scattered in the upper two thirds of jejunal villi. Double staining showed that GAD65 immunoreactivity was not found in goblet cells. (3)H-thymidine-labeled nuclei were found in the lower and middle portions of jejunal crypts, which was consistent with PCNA staining. Therefore, GABA and GAD65 were expressed in a maturation or functional zone. CONCLUSION: The characteristic expression of GABA and GAD suggests that GABA might be involved in regulation of differentiation and maturation of epithelial cells in rat jejunum.

Differences in endoscopic classification of early colorectal carcinoma between China and Japan: a comparative study.

AIM: To compare the differences in the endoscopic classification of early colorectal carcinoma (CRC) between Japan and China. METHODS: Ten cases of early CRC were included in the study. After reviewing the color pictures of these cases, 5 Japanese endoscopists and 5 Chinese endoscopists made their classificatory diagnosis individually using the current Japanese classification, and indicated their findings on which the diagnosis was based. RESULTS: Some lesions diagnosed by the Japanese endoscopists as IIa or IIa plus IIc, were classified as Is or Isp by the Chinese endoscopists. For superficial lesions consisting of elevation plus central depression, IIa plus depression, IIa plus IIc or IIc plus IIa were classified according to the ratio of elevated area/depressed area. However, international as well as interobserver difference still existed in the classification of such lesions. In addition, most Chinese endoscopists overlooked slightly depressed part on the top of a protruded lesion. Laterally spreading tumor, a special type of IIa, was identified as LST by some Japanese endoscopists. CONCLUSION: Discrepancies on macroscopic classification for early CRC do exist between Japanese and Chinese endoscopists, which are found not only in terminology but also in recognition of some lesions. In order to develop a universal classification, it needs for international communication and cooperation.