Bone marrow-derived mesenchymal stem cell transplantation ameliorates oxidative stress and restores intestinal mucosal permeability in chemically induced colitis in mice

BACKGROUND

Ulcerative colitis (UC) can be viewed as an autoimmune disease. Bone marrow-derived mesenchymal stem cells (MSCs) with its regenerative, cellular multi-lineage and immunomodulatory abilities can influence the repair of damaged tissues in UC. This study investigated the effects of MSCs transplantation on the mice intestinal barrier in response to oxidative stress injury.

METHODS

Colitis was induced by daily consecutive administration of 5% dextran sulfate sodium (DSS) solution for 7 days. Male murine MSCs were isolated and transplanted into female mice via injection in the tail vein. Serum and colon specimens were collected at 12 h, 24 h, 3 d, 7 d and 14 d after injection. Serum levels of D-lactate (D-LAC), diamine oxidase (DAO), colonic levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were quantified. The SRY protein of the male sex determinant gene expression and E-cadherin were also ascertained intracellularly.

RESULTS

Three days after receiving male MSCs transplantation, SRY protein expression was detected. The quantity increased on successive days. Serum levels of D-LAC and DAO, colonic MDA and SOD normalized in a shorter time period compared to controls (p<0.05). Not surprisingly, histological regeneration of tissue and E-cadherin expression in the colon of MSCs transplanted mice also occurred in a shorter time period than controls.

CONCLUSIONS

Transplanted MSCs restored mucosal permeability, and minimized oxidative stress related injury.

Application of dsRNA in cancer immunotherapy: current status and future trends

Cancer cells create a microenvironment that prevents tumor rejection by the host's immune system. The activation of pattern recognition receptors (PRRs) can elicit an innate immune response and guide the adaptive immune response to overcome this. dsRNA analogs can trigger TLR3, RIG-I, MDA5, NLRP3 and several other PRRs to induce not only robust immune response against cancer but also programmed cell death. This review focuses on the signal pathways activated by dsRNA and examines examples of their clinical application in cancer treatment.

The effects of TLR activation on T-cell development and differentiation

Invading pathogens have unique molecular signatures that are recognized by Toll-like receptors (TLRs) resulting in either activation of antigen-presenting cells (APCs) and/or costimulation of T cells inducing both innate and adaptive immunity. TLRs are also involved in T-cell development and can reprogram Treg cells to become helper cells. T cells consist of various subsets, that is, Th1, Th2, Th17, T follicular helper (Tfh), cytotoxic T lymphocytes (CTLs), regulatory T cells (Treg) and these originate from thymic progenitor thymocytes. T-cell receptor (TCR) activation in distinct T-cell subsets with different TLRs results in differing outcomes, for example, activation of TLR4 expressed in T cells promotes suppressive function of regulatory T cells (Treg), while activation of TLR6 expressed in T cells abrogates Treg function. The current state of knowledge of regarding TLR-mediated T-cell development and differentiation is reviewed.

Low incidence of complications from endoscopic gastric variceal obturation with butyl cyanoacrylate

BACKGROUND & AIMS

Endoscopic variceal obturation with tissue adhesive is used to control gastric variceal bleeding. We investigated the prevalence of serious complications from this therapy.

METHODS

We performed a retrospective analysis of complications that occurred in 753 patients with gastric variceal hemorrhages who were hospitalized in 2 tertiary referral hospitals. All patients received N-butyl-2-cyanoacrylate as therapy for endoscopic variceal obturation.

RESULTS

Complications occurred in 51 patients. Thirty-three patients experienced rebleeding because of early-onset (within 3 months) extrusion of the N-butyl-2-cyanoacrylate glue cast (4.4%), 10 patients developed sepsis (1.3%), and 5 patients developed distant embolisms (0.7%; 1 pulmonary, 1 brain, and 3 splenic). One patient had major gastric variceal bleeding after endoscopic variceal obturation (0.1%), 1 developed a large gastric ulcer (0.1%), and 1 had mesentery hematoma, hemoperitoneum, and infection in the abdominal cavity (0.1%). The complication-related mortality was 0.53% (3 deaths from sepsis and 1 death from rebleeding after early-onset glue cast extrusion).

CONCLUSIONS

The occurrence of complications after endoscopic variceal obturation with N-butyl-2-cyanoacrylate in gastric varices treatment is rare.

Immunomodulatory effects of dsRNA and its potential as vaccine adjuvant

dsRNA can be detected by pattern recognition receptors, for example, TLR3, MDA-5, NLRP3 to induce proinflammatory cytokines responsible for innate/adaptive immunity. Recognized by endosomal TLR3 in myeloid DCs (mDCs), dsRNA can activate mDCs into mature antigen presenting cells (mAPCs) which in turn present antigen epitopes with MHC-I molecules to naïve T cells. Coadministration of protein and synthetic dsRNA analogues can elicit an antigen-specific Th1-polarized immune response which stimulates the CD8+ CTL response and possibly dampen Th17 response. Synthetic dsRNA analogues have been tested as vaccine adjuvant against viral infections in animal models. However, a dsRNA receptor, TLR3 can be expressed in tumor cells while other members of TLR family, for example, TLR4 and TLR2 have been shown to promote tumor progression, metastasis, and chemoresistance. Thus, the promising potential of dsRNA analogues as a tumor therapeutic vaccine adjuvant should be evaluated cautiously.

Induction of multispecific Th-1 type immune response against HCV in mice by protein immunization using CpG and Montanide ISA 720 as adjuvants

Recent studies demonstrate that Th1-type immune responses against a broad spectrum of hepatitis C virus (HCV) gene products are crucial to the resolution of acute HCV infection. We investigated new vaccine approaches to augment the strength of HCV-specific Th1-type immune responses. ELISPOT assay revealed that single or multiple protein immunization using both CpG ODN and Montanide ISA 720 as adjuvants induced much stronger IFN-gamma-producing Th1 responses against core, NS3 and NS5b targets than did the formulation without these adjuvants. Protein vaccination using CpG ODN and Montanide ISA 720 as adjuvants also greatly enhanced humoral responses to HCV core, E1/E2 and NS3. When specific IgG isotypes were assayed, protein immunization using CpG ODN and Montanide ISA 720 as adjuvants produced higher titers of IgG2a dominant antibodies than did protein immunization alone, indicating a more Th1-biased pathway. This increase in IgG2a is consistent with the induction of Th1 cells secreting IFN-gamma demonstrated by ELISPOT assay. In conclusion, protein immunization using CpG ODN and Montanide ISA 720 as adjuvants greatly enhanced cellular (Th1 type) as well as humoral immune responses against HCV in Balb/c mice. The use of adjuvants appears critical to the induction of Th1 immune responses during HCV vaccination with recombinant proteins.

Induction of potent cellular immune response in mice by hepatitis C virus NS3 protein with double-stranded RNA

Double-stranded RNA is produced during virus replication and, together with the viral antigen, is responsible for inducing host antivirus immunity. The hepatitis C virus (HCV) non-structural protein-3 (NS3) has been implicated in the immune evasion of HCV, and is one of the prime targets for inducing immunity against HCV infection. Mice were immunized with recombinant NS3 protein (rNS3) and poly (I:C) emulsified in Montanide ISA 720 (M720). Cytokine production was assayed by enzyme-linked immunospot assay, and CD4(+) IFN-gamma(+) T helper (Th) cells or CD8(+) IFN-gamma(+) cytotoxic T lymphocytes were detected by flow cytometry. Anti-NS3 titre and immunoglobulin G2a (IgG2a) and IgG1 levels were monitored by enzyme-linked immunosorbent assay. Administration of rNS3 formulated in poly (I:C) and M720 induced anti-NS3 titres with a predominantly IgG2a isotype comparable to those induced by rNS3 in CpG-ODN and M720. The cytokine profiles showed that this formulation induced a Th1-biased immune response with several-fold more interferon-gamma (IFN-gamma)-producing cells than interleukin-4-producing cells. In contrast, rNS3 in M720 induced a Th2-biased immune response. The frequency of IFN-gamma-producing CD4(+) and CD8(+) cells induced by rNS3 in poly (I:C) and M720 was significantly higher than that induced by rNS3, rNS3 in M720, or rNS3 in poly (I:C), and was comparable to that induced by rNS3 in CpG-ODN with M720. The antigen-specific CD8(+) T-cell immune response persisted for up to 7 months after immunization. In conclusion, poly (I:C) with rNS3 in M720 can elicit a strong and persistent Th1-biased immune response and a cytotoxic T-lymphocyte response through cross-priming in mice. This study highlighted a promising formulation for inducing an efficient cellular immune response against HCV that has potential for HCV vaccine development.

Vigorous hepatitis C virus-specific CD4+ and CD8+ T cell responses induced by protein immunization in the presence of Montanide ISA720 plus synthetic oligodeoxynucleotides containing immunostimulatory cytosine-guanine dinucleotide motifs

BACKGROUND

A prophylactic vaccine for hepatitis C virus (HCV) requires generation of strong humoral as well as CD4(+) and CD8(+) T cell responses.

METHODS

The immunomodulatory effects of the combination of 2 adjuvants, synthetic oligodeoxynucleotides containing immunostimulatory cytosine-guanine dinucleotide motifs emulsified with Montanide ISA720 (M-ISA720/CpG), were investigated using the murine model.

RESULTS

Administration of recombinant HCV (rHCV) nonstructural (NS) 3 and NS5B proteins plus M-ISA720/CpG (hereafter, "M-ISA720/CpG/rHCV protein") induced high anti-NS3 and anti-NS5B immunoglobulin (Ig) G titers, with the IgG2a isotype being predominant. NS3- and NS5B-specific interferon (IFN)- gamma - and interleukin-2-producing CD4(+) T cell responses, as assessed by enzyme-linked immunospot assay, were significantly more vigorous in mice immunized with M-ISA720/CpG/rHCV protein than in control mice immunized without adjuvant. NS3- and NS5B-specific IFN- gamma -producing CD8(+) T cell percentages, as measured by direct ex vivo intracellular cytokine staining assay, were, respectively, a mean+/-SD of 0.14% +/- 0.04% and 0.15% +/- 0.05% in mice immunized with M-ISA720/CpG/rHCV protein. Furthermore, boosting with recombinant NS3 expression plasmid DNA after priming with M-ISA720/CpG-adjuvanted rNS3 strikingly enhanced both CD4(+) and CD8(+) T cell responses.

CONCLUSION

Immunization with M-ISA720/CpG/rHCV protein is capable of inducing potent humoral as well as HCV-specific T helper type 1-biased CD4(+) and CD8(+) T cell responses. A DNA boost after a protein prime--a reversal of the conventional approach--may provide an alternative path to the development of an effective HCV vaccine.

Reversibility of experimental rabbit liver cirrhosis by portal collagenase administration

The regression of cirrhosis is associated with increased intrahepatic collagenolytic enzyme activity. We investigated whether collagenase supplementation via portal vein infusion can retard cirrhosis development and/or reverse cirrhosis. In all, 35 rabbits were initially assigned to study. However, because of high surgical mortality and infection, only 15 animals completed study. Four normal controls (group I) received olive oil subcutaneously (SC) for 12 weeks followed by normal saline portal perfusion for 12 weeks. Four (group II) received CCl(4) SC for 6 weeks followed by portal vein collagenase, 6 mg twice weekly, plus SC CCl(4) for 6 additional weeks and then killed. Four rabbits (group III) received CCl(4) SC for 12 weeks and then 6 mg of collagenase portally for 12 weeks, while three control rabbits (group IV) received CCl(4) for 12 weeks followed by saline for 12 weeks. After 12 weeks of CCl(4), liver hydroxyproline content of collagenase-treated group II (361.1+/-106.6 microg/g) was significantly reduced compared with group III+IV that had not yet received collagenase (589.0+/-162.9 microg/g; P<0.05). In the main comparison, hydroxyproline content of collagenase-treated group III (177.5+/-35.6 microg/g) was significantly decreased compared with saline-treated controls (446.3+/-150.1 microg/g; P<0.01). Further, liver histology showed complete regression of cirrhosis in the collagenase-treated animals. No toxicity of liver, kidney, lung, brain or heart was observed histologically. Anaphylaxis occurred in 2/35 original animals (one fatal). In conclusion, this study provides 'proof of principle' that collagenase portal administration can retard cirrhosis development and speed regression of established cirrhosis in the rabbit CCl(4) model. Potential application to humans is premature, but feasible, if these findings are confirmed in additional animal studies.

Cotreatment with interferon-alpha and -gamma reduces liver fibrosis in a rat model

Background/Aims: Interferon-alpha is used widely to treat viral hepatitis. Interferon-gamma modulates a system attacking infected cells and also has an anti-fibrotic effect. A treatment with interferon-alpha and -gamma has undergone trials in eliminating hepatitis C virus. We investigated effects of cotreatment in a liver fibrosis model to explore anti-fibrotic effects. Methods: Rats were assigned to groups including normal controls (NC), CCl(4) controls, rat interferon-alpha treatment, rat interferon-gamma treatment, and cotreatment. All groups except normal controls received CCl(4) orally for 8 weeks. At the beginning of the third week of exposure, 6 weeks of treatment were initiated according to interferon group. Digitally analyzed immunohistochemistry, biochemical assays, and Northern analysis were performed. Results: Pixels (x10(5)) per field containing immunoreactive type III collagen (fibrotic density) in CCl(4) controls, interferon-alpha, interferon-gamma, and cotreatment groups respectively were [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. Liver hydroxyproline content correlated with fibrotic density, and was significantly low in the cotreatment group. Plasma hyaluronate and transaminase were significantly low in cotreatment and interferon-alpha groups. Northern blotting showed lowest mRNA expression for type I collagen, desmin, transforming growth factor (TGF)-beta1, and matrix metalloproteinase-2 mRNA in the cotreatment group; tissue inhibitor of metalloproteinase-1 and -2 mRNAs were significantly low in the interferon-gamma group. Conclusions: Cotreatment can suppress collagen and transforming growth factor-beta1 and has an overall anti-fibrotic effect without exacerbating inflammation.

Increased expression of plasminogen activator and plasminogen activator inhibitor during liver fibrogenesis of rats: role of stellate cells

BACKGROUND/AIMS

Plasminogen activators and plasminogen activator inhibitors are important regulators of the balance between the proteolytic and antiproteolytic activities that determine extracellular matrix turnover. We examined the expression of plasminogen activator-plasmin system components in experimental liver fibrosis of rats.

METHODS

Liver fibrosis was produced in rats by injecting carbon tetrachloride for 6 to 12 weeks. Gene expression for plasminogen activator inhibitor-1 (PAI-1), urokinase and tissue plasminogen activators (uPA and tPA), urokinase plasminogen activator receptor (uPAR), and transforming growth factor-beta1 (TGF-beta1) was examined by Northern analysis. Western analysis was performed to detect protein expression of PAI-1, uPA and uPAR. An immunohistochemical study was performed to detect the localization of PAI-1. Additionally, primary cultured liver cells were examined by Northern and Western analyses for this protein with or without prior incubation with TGF-beta1.

RESULTS

At 6 weeks, when fibrosis had occurred, uPA and uPAR mRNAs had increased 2.8-fold and 1.8-fold, respectively; PAI-1 and tPA mRNA levels were unchanged. At the cirrhotic stage (9 to 12 weeks), mRNA levels for PAI-1, uPA, uPAR and tPA were all increased. Western analysis also showed increased uPA and uPAR expressions in fibrotic liver, and increased PAI-1, uPA and uPAR expressions in cirrhotic liver. PAI-1 protein was also demonstrated immunohistochemically along sinusoids, vessels, and bile duct cells of normal and fibrotic liver. In liver cell cultures, Kupffer cells, hepatocytes, and especially stellate cells, expressed PAI-1. Expression was enhanced in stellate cells cultured from fibrotic or cirrhotic liver or stimulated in vitro with TGF-beta1.

CONCLUSION

Though increased uPA and uPAR may act on matrix degradation in fibrotic liver, increased PAI-1 together with uPA, uPAR and tPA are associated with overall inhibition of matrix degradation in cirrhotic liver. Hepatic stellate cells are an important source of PAI-1 during liver fibrosis.

Spatial distribution of tissue inhibitor of metalloproteinase-1 mRNA in chronic liver disease

BACKGROUND/AIMS

Tissue inhibitor of metalloproteinase-1, a specific inhibitor of matrix metalloproteinases, plays an important role in the pathogenesis of fibrosis and tumor progression. However, the precise expression of tissue inhibitor of metalloproteinase-1 messenger RNA in human hepatic fibrosis has not yet been defined. We investigated the spatial distribution of tissue inhibitor of metalloproteinase-1 messenger RNA in chronic human liver disease.

METHODS

Northern and in situ hybridization of probes to tissue inhibitor of metalloproteinase-1 messenger RNA were performed in specimens from 16 surgically resected human livers. Immunohistochemical staining of sections for tissue inhibitor of metalloproteinase-1 and immunoelectron microscopy were also performed.

RESULTS

Northern hybridization demonstrated that expression of tissue inhibitor of metalloproteinase-1 messenger RNA was increased 3.9-fold in mild chronic hepatitis, 6.8-fold in moderate chronic hepatitis, and 6.4-fold in cirrhosis, compared with control liver. In situ hybridization showed the expression of tissue inhibitor of metalloproteinase-1 messenger RNA in spindle-shaped cells in the fibrous septa and lobules in chronic hepatitis and cirrhosis; these cells were immunohistochemically positive for a-smooth muscle actin. Immunoelectron microscopy revealed localization of tissue inhibitor of metalloproteinase-1 in between fibers, to the rough endoplasmic reticula of stellate cells located in the lobules and periportal areas, and to fibroblasts in the fibrous septa. These results indicate that tissue inhibitor of metalloproteinase-1 was produced mainly by stellate cells in the specimens of chronic liver diseases.

CONCLUSIONS

Expression of tissue inhibitor of metalloproteinase-1 messenger RNA is increased in hepatic fibrosis and stellate cells are involved primarily in its expression.

Dual expression of matrix metalloproteinase-2 and membrane-type 1-matrix metalloproteinase in fibrotic human livers

We have previously reported increased expression of matrix metalloproteinase-2 (MMP-2) using a rat model of liver fibrosis. However we did not clarify how the precursor of MMP-2 (proMMP-2) was activated. Therefore, we used human liver specimens with chronic hepatitis (CH) and liver cirrhosis (LC) to examine expression of membrane-type-1-MMP (MT1-MMP), which has recently been determined to activate proMMP-2. Northern hybridization studies showed a 5.4- and 1.4-fold increase in MMP-2 expression in CH and LC, respectively, as compared with normal liver. MT1-MMP gene expression simultaneously increased 4.0- and 1.4-fold in CH and LC, respectively. In situ hybridization using 35S-cRNA probes of MMP-2 and MT1-MMP showed prominent silver granules in elongated cells found in the lobules, periportal areas, and fibrous septa of CH and LC samples. These elongated cells expressed alpha-smooth muscle actin by immunohistochemistry. Immunoelectron microscopic examination localized MMP-2 and MT1-MMP to the rough endoplasmic reticulum of stellate cells located in the lobules and periportal areas, or to fibroblasts in the fibrous septa, suggesting that MMP-2 and MT1-MMP were produced by these cells. In addition, cytoplasmic and membranous immunodeposits of both MMPs were found in endothelial cells, Kupffer cells, capillary endothelial cells, and lymphocytes, indicating that activation of proMMP-2 occurs locally. Increased expression of MMP-2 and MT1-MMP was detected in CH and LC, while dual over-expression was found in stellate cells and fibroblasts, possibly resulting in the increase of active MMP-2 in and around these cells. These findings suggest that activated MMP-2 may remodel liver parenchyma during the process of liver fibrosis.