Protective effect of hydrogen sulfide on TNF-α and IFN-γ-induced injury of intestinal epithelial barrier function in Caco-2 monolayers.

BACKGROUND AND AIM: Studies have verified the protective effect of Hydrogen Sulfide (H2S) on gastric ulcer and ulcerative colitis, but the mechanisms are not fully illustrated. In this study, the possible protective effect of H2S on TNF-α/IFN-γ induced barrier dysfunction was investigated in Caco-2 cell monolayers. METHOD: The barrier function of Caco-2 monolayers was evaluated by measuring trans-epithelial electrical resistance (TEER) and FITC-Dextran 4 kDa (FD-4) trans-membrane flux. ZO-1 and Occludin were chosen as markers of the localization of tight junction (TJ) proteins for immunofluorescence. The expression of MLCK and phosphorylation level of myosin light chain (MLC) were measured by immunoblotting. The activation of NF-kB p65 was analyzed by EMSA and immunofluorescence. RESULTS: NaHS at 500 uM significantly attenuated TNF-α/IFN-γ-indueced Caco-2 monolayer barrier injury. The increased expression of MLCK and increased phosphorylation level of MLC induced by TNF-α/IFN-γ was also inhibited significantly by NaHS. Additionally, NaHS inhibited TNF-α/IFN-γ induced activation and nuclear translocation of NF-kB p65. CONCLUSION: The present study reveals the protective effect of H2S on TNF-α and IFN-γ-induced injury of intestinal epithelial barrier function in Caco-2 monolayers and suggests that the suppression of MLCK-P-MLC signaling mediated by NF-kB P65 might be one of the mechanisms underlying the protective effect of H2S.

Cucurbit[7]uril as the host of adamantane-modified dyes for fluorescence enhancement in aqueous environments.

Taking advantage of the excellent host-guest complexation ability between an auxochrome (adamantane group) and CB[7], the fluorescence emission performance of dyes in water was effectively improved with the addition of two equivalents of CB[7], which provided an efficient method for increasing fluorescence intensity in aqueous environments. Furthermore, these dyes with the host were successfully used in cell imaging.

[Experimental study of radiofrequency ablation of liver in swine].

OBJECTIVE: To explore the feasibility and efficacy of multiple-radiofrequency ablation (RFA) in swine liver. METHODS: One swine undergone percutaneous and intra-operative RFA for three times in succession (an interval of 5 days) guided by real-time ultrasound. Then 6 ablated lesions formed. The outcome of RFA and the change of tissues adjacent to ablated lesions (biliary, liver vascular and abdominal wall) were observed by trans-abdominal ultrasonography (US), contrast enhanced ultrasound (CEUS), intra-operative ultrasound (IOUS) and contrast enhanced computed tomography (CT). RESULTS: Bile duct dilatation was found beside primary porta hepatis on US, CT, IOUS after RFA. There was no thrombus in liver vein through the ablated lesion with electrodes parallel to primary porta hepatis. Two ablated lesions were incompletely fused together. Small thermal injury was observed on abdominal wall after an injection of saline into subcapsular gap. Subcapsular hepatic tissue around ablation lesion changed into coagulative necrosis from hyperemia with elapsing time. Carbonizing granule formed during RFA on the top of intro-operative radio-frequency electrode easily caused bleeding along the withdrawing passage. Gelfoam was helpful to stop bleeding during intro-operative RFA. Occluding blood flow into liver definitely enlarged ablated area with the same amount of RFA energy. CONCLUSION: Multiple-RFA is feasible and efficacious for patients with RFA indication. But the complications of RFA increase if the ablation areas are adjacent to such organs as bile duct, stomach, intestine and diaphragm, etc.

[Malaria epidemic trend and characteristics at monitoring sites in Yunnan province in 2008].

Malaria situation in 5 monitoring sites of Yunnan showed a decline trend from 2005 to 2008. The average malaria incidence in 2008 was 11.84/10,000 with a decrease of 66.1% in comparison to 2005. The seropositive rate with immuno-fluorescence assay (IFA) was 4.61% for pupils. 82% of the cases chose town or township hospitals as the first place of seeking diagnosis and treatment. 83.6% cases were diagnosed over 3 days of symptom appearing. The main clinical manifestation was fever every other day attack (occupied 72.7%). 98.4% of the cases were with light symptoms. The proportion of primary attacks and relapses among malaria patients were 95.3% and 4.7%, respectively. Plasmodium vivax was the main malaria parasite, occupying 81.2%. 97.2% of the local infected cases were found in the bordering areas of the country. The mosquito net utilization rate was 51.4%. Results showed that malaria has been effectively controlled in the monitoring sites of Yunnan.

[Serological detection of malaria for people entering China from 19 ports of entry covering 8 border prefectures of Yunnan].

OBJECTIVE: To evaluate malaria situation in areas of Yunnan Province bordering with Myanmar, Laos and Vietnam. METHODS: Blood samples on filter paper were collected from the entry people in March to December of 2007 involving 19 national and provincial ports of entry. Indirect fluorescent antibody test (IFAT) was carried out by using the blood samples collected before June 30 as the first half year and after July 1 as the second half year. Analysis was made on the relationship of IFAT positive rate and GMRT to malaria incidence in the province reported by the China information system for disease control and prevention. RESULTS: IFAT positive rate in the first half year (5.6%) was 20.9% higher than that of second half year (4.4%) (chi2=12.95%, P<0.05). There was a positive correlation between IFAT positive rate and the number of malaria cases reported in 2007 from the 8 bordering prefectures (r=0.8124, P<.05). The highest IFAT positive rate was found in Dehong (8.7%), Baoshan (7.1%), and Lingcang (65%). Among the 19 entry ports, the highest IFAT positive rate was found in 5 entry ports: Lvliang, Laying, Jiegao, Houqiao, and Qingshuihe, all in China-Myanmar border. The IFAT positive rate in the Chinese entry people increased with their days of staying outside the border. Among the entry people, the highest antibody positive rate was from those of Myanmar nationality (11.7%) followed by those from Yunnan (3.7%). CONCLUSION: To certain extent, higher malaria incidence outside the border impacts that of Yunnan Province.

Multisite survey of bacterial contamination in ready-to-eat meat products throughout the cooking and selling processes in urban supermarket, Nanjing, China.

OBJECTIVE: Ready-to-eat (RTE) meat is a kind of popular instant food easily contaminated by microbes, which is one of the causes of foodborne diseases. This study analyzes the possible sources of RTE food bacterial contamination during processing and subsequent selling. METHOD: Samples of eight kinds of RTE meat were collected from four supermarkets in Nanjing, China. The knives, chopping boards, trays(containers of food), clamps, air, water, and hands of the sales staff were sampled, and the enumeration of aerobic plate count and total coliforms and pathogenic bacteria was performed. RESULTS: The survey revealed that poor hygienic levels was the causes that RTE meat products were contaminated by bacteria at different levels. With regard to pathogen, the incidences of Salmonella spp. and Staphylococcus aureus were 4.2% and 2.1%, respectively. These results also revealed that the bacterial contamination of RTE food was caused by the air, as well as clamps, chopping boards, knives, trays, and hands of the operators. The total number of aerobic colonies were positively correlated with the amount of RTE food in one pot (r = .87728, p = .0217), and negatively correlated with the maximum temperature in the center of the meat (r = -.81633, p = .0475). CONCLUSION: The high number of bacteria in RTE foods indicates potential food safety risks and the need to improve the health of supermarket sales staff. The most important thing is to determine how to raise hygiene awareness of employees through food safety education. Meanwhile, a comprehensive set of regulations on hand cleaning and disinfection should be developed to facilitate public health and reduce foodborne illness caused by the consumption of RTE food.

[Effect of external counterpulsation on morphological damage of endomembrane and endothelium-dependent vasodilatation in the carotid arteries in hypercholesterolemic pigs].

OBJECTIVE: To explore the effect of long-term enhanced external counterpulsation (EECP) on morphological damage of endomembrane and endothelium-dependent vasodilatation of the carotid arteries of hypercholesterolemic pigs. METHODS: Eighteen male infant pigs were randomly divided into three groups according to the contents of their diet: the normal control group (n=6), the high-cholesterol feeding control group (n=6) and EECP group (n=6). Porcine model of hypercholesterolemia was reproduced by feeding animals with high-cholesterol diet. After completion of EECP treatment for 36 hours in EECP group, carotid arterial rings were harvested from all animals. Both scanning and transmission electron microscopy was employed to observe the changes in morphology of their endomembrane. At the same time, their vasodilatation response to variant dose of acetylcholine (Ach) was detected. RESULTS: The surface of endothelium in the normal control group was smooth, and endothelial cells were in regular streamline array, and they were almost in same size, attaching closely to matrix without smooth muscle cell proliferation and lipid infiltration in intima. In contrast, the endothelial cells of hypercholesterolemic pigs were in irregular array, with marked desquamation, resulting in loose linkage. Smooth muscle cells were found to invade into intimal layer and proliferated, and foam cells could also be found in intimal layer. In hypercholesterolemic pigs treated with EECP, slight intimal damage was found. In addition, with Ach dose of 10(-8) mol/L to 10(-5)mol/L, endothelium-dependent vasodilatation ratio in hypercholesterolemic pigs with or without EECP treatment, was significantly lower than that of the normal control group (all P<0.05). However, endothelium-dependent vasodilatation ratio in pigs with EECP treatment was obviously higher compared with hypercholesterolemic pigs without EECP treatment with the dosage of Ach concentration ranged from 10(-7) mol/L to 10(-5) mol/L (all P<0.05). CONCLUSION: Long-term EECP ameliorates both the morphological damage and the impaired endothelium-dependent vasodilatation function resulting from hypercholesterolemia, contributing to prevention of atherosclerosis.

[Malaria situation in Yunnan Province during 2001-2005].

OBJECTIVE: To analyze the trends of malaria incidence from 2001 to 2005 in Yunnan Province. METHOD: Malaria data in 2001-2005 were collected and statistically analyzed by using Microsoft excel 2003 and ArcView GIS 3.3 software. RESULTS: Among 63,562 malaria cases reported in the 5 years from 129 counties of 16 prefecture in the province, the average annual malaria incidence was 3.049/10,000 with an increase of 4.67% than the previous 5 years chi2 = 63.15, P < 0.05). There were 2 peaks of malaria incidence: May to August and October to November. Five prefectures with the highest malaria incidence were the prefecture bordering to the southern nations, and counties ranged first ten places of malaria incidence were all at the first line border areas besides Liang-He County which is in the second line border area. There were 23 counties with malaria incidence higher than 5 per ten thousand, occupying 80. 31% of all cases in the province but only 12.74% of the population. 87.30% of the cases and 79.36% of the death occurred in those under 45 years-old. Farmers, laborers and students were at the high-risk of malaria infection. Moving population accounted for 17.06% of the cases and 23.42% of the death in the province. CONCLUSION: Malaria is still an important part of public health in Yunnan Province, and people younger than 45 years-old, farmers, laborers and moving population are at the high risk for malaria infection.

Reactive oxygen species inhibits Listeria monocytogenes invasion into HepG2 epithelial cells.

Listeria monocytogenes (Lm) can colonize human gastrointestinal tract and subsequently cross the intestinal barrier. Reactive oxygen species (ROS) are produced by NADPH oxidase. However, the role of ROS in bacterial invasion remains to be less understood. Herein, we investigated the impact of ROS on Lm invasion to HepG2 using NADPH oxidase inhibitor, diphenyleneiodonium chloride (DPI), as well as the ROS scavenger, N-acetyl cysteine (NAC). Our results showed that inhibiting ROS increased the invasive capability of Lm. Moreover, after Lm infection, inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin 1beta (IL-1ß) in HepG2 were significantly upregulated. However, after inhibiting ROS, the expression levels of TNF-α and IL-1ß were downregulated, indicating a failure of host cells to activate the immune mechanism. Taken together, ROS in Lm might be as a signal for host cells to sense Lm invasion and then stimulate cells to activate the immune mechanism.

Influence of 2,4-dinitrophenol on the characteristics of activated sludge in batch reactors.

The response of activated sludge characteristics to the presence of 2,4-dinitrophenol (dNP) in batch cultures was investigated in this study. The sludge yield slightly decreased with an increase in dNP concentration. At 10 mg l(-1), or lower, dNP significantly reduced sludge yield and relative specific growth rates (mu/mu0), but didn't substantially affect its relative specific chemical oxygen demand removal rate (q/q0). Presence of dNP at 1-20 mg l(-1) increased the specific oxygen uptake rate of activated sludge, and slightly changed its hydrophobicity. An analysis on inhibition indicated that the reduction in sludge yield in the presence of dNP was mainly attributed to the significant decreased sludge growth, rather than the reduced substrate degradation.

Overexpression of long non-coding RNA H19 is associated with unfavorable prognosis in patients with colorectal cancer and increased proliferation and migration in colon cancer cells.

Long non-coding RNA-imprinted maternally expressed transcript (non-protein coding) (H19) has been previously identified to be involved in the development of a number of types of cancer. However, the function of H19 in the pathogenesis of colorectal cancer remains unclear. The expression level of H19 in colorectal tumor tissues, and the association between H19 expression and clinicopathological variables and prognosis was investigated in the present study. In addition, the effect of H19 overexpression on viability, migration and epithelial-mesenchymal transition (EMT) of colon cancer cells was investigated in HCT-116 and SW-480 cells. The results of the present study suggest that overexpression of H19 is associated with decreased recurrence-free survival and overall survival rates in patients with colorectal cancer, and increased viability and migration in colon cancer cells. The induction of the EMT process may be an underlying molecular mechanism associated with the H19-induced increased metastasis potential of colon cancer cells.

Targeting HCCR expression resensitizes gastric cancer cells to chemotherapy via down-regulating the activation of STAT3.

The human cervical cancer oncogene (HCCR) has been found to be overexpressed in a variety of human cancers. However, the level of expression of HCCR and its biological function in gastric cancer are largely unknown. In this study, we evaluated HCCR expression in several gastric cancer cell lines and in one normal gastric mucosal cell line. We established a 5-FU-resistant gastric cancer cell subline, and we evaluated its HCCR expression. HCCR expression levels were high in gastric cancer lines, and expression was significantly increased in the 5-FU-resistant cancer cell subline. HCCR expression affected cell growth by regulating apoptosis in the cancer cells, and it had a positive correlation with p-STAT3 expression. Western blot and luciferase reporter assays showed that the activation of STAT3 upregulated HCCR expression in a positive feedback loop model. In vivo and in vitro studies showed that HCCR plays an important role in the apoptosis induced by 5-FU. Our data demonstrate that HCCR is probably involved in apoptosis and cancer growth and that it functions as a p-STAT3 stimulator in a positive feedback loop model. In gastric cancer cells, HCCR confers a more aggressive phenotype and resistance to 5-FU-based chemotherapy.

Effect of Long Noncoding RNA H19 Overexpression on Intestinal Barrier Function and Its Potential Role in the Pathogenesis of Ulcerative Colitis.

BACKGROUND: Recently, long noncoding RNA (lncRNA) H19 has been reported to be related with VDR signaling and the development of inflammatory diseases including osteoarthritis. The aim of this study was to investigate the correlation between the expression level of H19 and VDR in ulcerative colitis (UC) tissues and to investigate the effect of H19 overexpression on intestinal epithelial barrier function. METHODS: The expression level of H19, miR-675-5p, and VDR in UC tissues and paired normal tissues collected from 12 patients with UC was investigated by quantitative real-time polymerase chain reaction. Caco-2 monolayers were used to test the effect of H19 and miR-675-5p overexpression on the intestinal epithelial barrier function and the status of tight junction proteins and VDR. Luciferase assay was used to validate the target site of miR-675-5p in the 3'UTR of VDR mRNA. RESULTS: The expression of H19 was found to be negatively correlated with the expression of VDR in UC tissues (r = 0.5369, P < 0.05). The expression of miR-675-5p was also found to be negatively correlated with the expression of VDR in UC tissues (r = 0.5233, P < 0.01). H19 overexpression increased Caco-2 monolayer permeability and decreased the expression of tight junction proteins and VDR, which was significantly attenuated by cotransfection with miR-675-5p inhibitors. The 3'UTR of VDR mRNA was validated to be one of the direct targets of miR-675-5p. CONCLUSIONS: This study reveals the destructive effect of H19 overexpression on intestinal epithelial barrier function and suggests a potential role of H19 in the development of UC. In addition, H19 overexpression may be one of the mechanisms underlying the decreased expression of VDR in UC tissues and the interaction between H19 and VDR signaling may provide potential therapeutic targets for UC.

A three-dimensional registration method for automated fusion of micro PET-CT-SPECT whole-body images.

Micro positron emission tomography (PET) and micro single-photon emission computed tomography (SPECT), used for imaging small animals, have become essential tools in developing new pharmaceuticals and can be used, among other things, to test new therapeutic approaches in animal models of human disease, as well as to image gene expression. These imaging techniques can be used noninvasively in both detection and quantification. However, functional images provide little information on the structure of tissues and organs, which makes the localization of lesions difficult. Image fusion techniques can be exploited to map the functional images to structural images, such as X-ray computed tomography (CT), to support target identification and to facilitate the interpretation of PET or SPECT studies. Furthermore, the mapping of two functional images of SPECT and PET on a structural CT image can be beneficial for those in vivo studies that require two biological processes to be monitored simultaneously. This paper proposes an automated method for registering PET, CT, and SPECT images for small animals. A calibration phantom and a holder were used to determine the relationship among three-dimensional fields of view of various modalities. The holder was arranged in fixed positions on the couches of the scanners, and the spatial transformation matrix between the modalities was held unchanged. As long as objects were scanned together with the holder, the predetermined matrix could register the acquired tomograms from different modalities, independently of the imaged objects. In this work, the PET scan was performed by Concorde's microPET R4 scanner, and the SPECT and CT data were obtained using the Gamma Medica's X-SPECT/CT system. Fusion studies on phantoms and animals have been successfully performed using this method. For microPET-CT fusion, the maximum registration errors were 0.21 mm +/- 0.14 mm, 0.26 mm +/- 0.14 mm, and 0.45 mm +/- 0.34 mm in the X (right-left), Y (upper lower), and Z (rostral-caudal) directions, respectively; for the microPET-SPECT fusion, they were 0.24 mm +/- 0.14 mm, 0.28 mm +/- 0.15 mm, and 0.54 mm +/- 0.35 mm in the X, Y, and Z directions, respectively. The results indicate that this simple method can be used in routine fusion studies.

[Change in endothelial progenitor cells and endothelial function in patients with unstable angina pectoris].

OBJECTIVE: To investigate the relationship between endothelial progenitors cells (EPCs) and endothelium-dependent vasodilation in patients with unstable angina pectoris. METHODS: Thirty patients with unstable angina pectoris (UAP) and thirty control subjects were recruited. Flow-mediated dilation (FMD) in the brachial artery was evaluated by using ultrasound Doppler flow method. The number of circulating EPCs was analyzed by flow cytometry analysis. Total mononuclear cells were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. CD34 antigen of adherent cells was identified by immunohistochemical assay. EPCs were characterized as adherent cells double positive for FITC-UEA-I binding and DiI-acLDL uptake by direct fluorescent staining under inverted fluorescent microscope. RESULTS: FMD was significantly impaired in the UAP group compared with the control group (5.93% +/- 2.67% vs 11.1% +/- 4.36%, P < 0.05). There was no significant difference in NMD between two groups (13.60% +/- 5.03% vs 14.18% +/- 4.50%, P > 0.05). The number of CD34(+) cells significantly increased in the UAP group compared with the control group (0.13% +/- 0.05% vs 0.09% +/- 0.04%, P < 0.05). There was a negative association between impaired FMD and increased CD34(+) cell (r = -0.385, P < 0.05). A positive antigen of CD34 of adhesion cells and double positive adhesion cells were found. CONCLUSION: This study shows that the levels of peripheral CD34(+) cells in patients with UAP increase with an impaired endothelial function. The increase in EPCs may be an important compensatory response to acute coronary ischemia and impaired endothelium in patients with UAP.

[Impaired endothelium-dependent vasodilation and arterial elasticity in patients with coronary artery disease].

OBJECTIVE: To investigate the change in endothelium-dependent vasodilation and arterial elasticity and the association between them in patients with coronary artery disease (CAD). METHODS: Thirty patients with CAD and thirty control subjects were recruited for this study. Flow-mediated dilation (FMD) in the brachial artery was evaluated by ultrasound Doppler flow method. They also underwent a non-invasive assessment of C(1) large artery and C(2) small artery indices by using pulse wave analysis. RESULTS: FMD was significantly reduced in CAD group compared with that in control group [(5.17 +/- 2.13)% vs (11.1 +/- 4.36)%, P < 0.05], C(1) large artery elasticity index was similar between the two groups [(11.59 +/- 4.56) ml/mm Hg x 10 vs (12.11 +/- 3.82) ml/mm Hg x 10, P > 0.05]. However, C(2) small artery elasticity index was significantly reduced in CAD group compared with that in control group [(4.20 +/- 1.80) ml/mm Hg x 100 vs (6.26 +/- 2.36) ml/mm Hg x 100, P < 0.05]. There was a positive association between reduced C(2) small artery elasticity index and impaired FMD (r = 0.53, P < 0.05). CONCLUSIONS: There were impaired endothelium-dependent vasodilation and reduced C(2) small artery elasticity index in the patients with CAD, which were closely correlated with each other. The present study suggested that the measurement of C(2) small artery elasticity might be used as a novel index for the determination of endothelial function.

[A study of association between age-related circulating endothelial progenitor cells and arterial elasticity].

OBJECTIVE: Reduced arterial elasticity is a hallmark of aging in healthy humans independently of diseases and endothelial-cell injury and dysfunction may be responsible for this fall in arterial elasticity. We hypothesized that circulating endothelial progenitor cells (EPCs) are involved in endothelial repair and that lack of EPCs contributes to impaired arterial elasticity. METHODS: A total of 56 healthy male volunteers were divided into young (n = 26) and elderly (n = 30) groups. Large and small artery elasticity indices were non-invasively assessed by using pulse wave analysis. Flow cytometer was used to count the number of circulating CD34(+) mononuclear cells (MNCs), which were isolated from peripheral blood by Ficoll density gradient centrifugation, and then the cells were plated on fibronectin-coated culture dishes. EPCs were characterized as adherent cells double positive staining for DiI-acLDL uptake and lectin binding with using fluorescent microscope. RESULTS: C(1) (large artery elasticity index) and C(2) (small artery elasticity index) were significantly reduced in the elderly group compared with those in the young group (11.73 +/- 1.45 vs 16.89 +/- 1.69 ml/mm Hg x 10, P < 0.001; 8.40 +/- 1.45 vs 10.58 +/- 1.18 ml/mm Hg x 100, P < 0.001 respectively). In parallel, the number of circulating EPCs was significantly reduced in the elderly group compared with the young group (0.13 +/- 0.02 vs 0.17 +/- 0.04%, P < 0.05). The number of circulating EPCs correlated with C(1) large and C(2) small artery elasticity indices (r = 0.47, P < 0.01; r = 0.4, P < 0.01). Fluorescent microscope was used to identify EPCs, which were double positive staining for DiI-acLDL uptake and lectin binding. CONCLUSION: The present findings suggested that the fall in circulating EPCs with subsequently impaired endothelial-cell repair and function might contribute to reduced arterial elasticity in humans with aging. The decrease in circulating EPCs could serve as a surrogate biologic measure of vascular function and human age.

Protective effect of 1,25-dihydroxyvitamin d3 on lipopolysaccharide-induced intestinal epithelial tight junction injury in caco-2 cell monolayers.

Lipopolysaccharide was found to be elevated in the plasma of necrotizing enterocolitis (NEC) and inflammatory bowel disease (IBD) patients and may play an important role in the pathogenesis and propagation of these intestinal diseases. To illustrate the destructive effect of lipopolysaccharide (LPS) and to test the protective effect of 1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) on LPS-induced barrier injury, an in vitro intestinal epithelia barrier model was established with Caco-2 monolayers and treated with clinically relevant concentrations (1-10 ng/ml) of LPS with or without 1,25(OH)2D3. Transepithelial electrical resistance (TEER) and FITC-Dextran 40kda (FD-40) flux were measured to reflect monolayer permeability. We found that LPS at clinically relevant concentrations increased intestinal permeability by downregulating and redistributing tight junction (TJ) proteins. 1,25(OH)2D3 added at baseline or at day 4 abrogated the destructive effect of LPS on monolayer permeability by restoring the expression and localization of TJ proteins. LPS, at clinically relevant concentrations, also downregulated the expression of vitamin D receptor (VDR); 1,25 (OH)2D3, however, could restore the expression of VDR. Our findings illustrate the mechanism underlying the destructive effect of clinically relevant concentrations of LPS on intestinal TJ barrier and provide evidence for the clinical application of vitamin D in LPS-related intestinal barrier dysfunction.

Intestinal alkaline phosphatase inhibits the translocation of bacteria of gut-origin in mice with peritonitis: mechanism of action.

Exogenous intestinal alkaline phosphatase (IAP), an enzyme produced endogenously at the brush edge of the intestinal mucosa, may mitigate the increase in aberrant intestinal permeability increased during sepsis. The aim of this study was to test the efficacy of the inhibitory effect of IAP on acute intestinal inflammation and to study the molecular mechanisms underlying IAP in ameliorating intestinal permeability. We used an in vivo imaging method to evaluate disease status and the curative effect of IAP. Two Escherichia coli (E.coli) B21 strains, carrying EGFP labeled enhanced green fluorescent protein (EGFP) and RFP labeled red fluorescent protein (RFP), were constructed as tracer bacteria and were administered orally to C57/B6N mice to generate an injection peritonitis (IP) model. The IP model was established by injecting inflammatory lavage fluid. C57/B6N mice bearing the tracer bacteria were subsequently treated with (IP+IAP group), or without IAP (IP group). IAP was administered to the mice via tail vein injections. The amount of tracer bacteria in the blood, liver, and lungs at 24 h post-injection was analyzed via flow cytometry (FCM), in vivo imaging, and Western blotting. Intestinal barrier function was measured using a flux assay with the macro-molecule fluorescein isothiocyanate dextran, molecular weight 40kD, (FD40). To elucidate the molecular mechanism underlying the effects of IAP, we examined the levels of ERK phosphorylation, and the expression levels of proteins in the ERK-SP1-VEGF and ERK-Cdx-2-Claudin-2 pathways. We observed that IAP inhibited the expression of Claudin-2, a type of cation channel-forming protein, and VEGF, a cytokine that may increase intestinal permeability by reducing the levels of dephosphorylated ERK. In conclusion, exogenous IAP shows a therapeutic effect in an injection peritonitis model. This including inhibition of bacterial translocation. Moreover, we have established an imaging methodology for live-animals can effectively evaluate intestinal permeability and aberrant bacterial translocation in IP models.

Protective effect of 1,25-dihydroxyvitamin D3 on ethanol-induced intestinal barrier injury both in vitro and in vivo.

Studies have suggested the role of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in protecting intestinal barrier function from injuries induced by multiple reagents. Vitamin D deficiency was reported to be associated with poor prognosis in patients with alcoholic liver disease (ALD). This study is designed to investigate the effect of 1,25(OH)2D3 on ethanol-induced intestinal barrier dysfunction and the underlying mechanisms utilizing Caco-2 cell monolayers and a mouse model with acute ethanol injury. In Caco-2 monolayers, ethanol significantly increased monolayer permeability, disrupted TJ distribution, increased phosphorylation level of MLC, and induced generation of ROS compared with controls. However, pre-treatment with 1,25(OH)2D3 greatly ameliorated the ethanol-induced barrier dysfunction, TJ disruption, phosphorylation level of MLC, and generation of ROS compared with ethanol-exposed monolayers. Mice fed with vitamin d-sufficient diet had a higher plasma level of 25(OH)D3 and were more resistant to ethanol-induced acute intestinal barrier injury compared with the vitamin d-deficient group. These results suggest that the suppression of generation of ROS and increased phosphorylation level of MLC might be one of the mechanisms underlying the protective effect of 1,25(OH)2D3 on ethanol-induced intestinal barrier injury and provide evidence for the application of vitamin D as therapeutic factors against ethanol-induced gut leakiness.