To assess the clinical efficacy of alternative techniques for biliary stricture cannulation in patients undergoing living donor liver transplantation (LDLT), after cannulation failure with a conventional (0.035-inch guidewire) technique.
Subjects and Methods
Of 293 patients with biliary strictures after LDLT, 19 (6%) patients, 11 men and 8 women of mean age 48.5 years, had the failed cannulation of the stricture by conventional techniques. Recannulation was attempted by using two alternative methods, namely a micro-catheter set via percutaneous access and a snare (rendezvous) technique using percutaneous and endoscopic approaches.
Strictures were successfully cannulated in 16 (84%) of the 19 patients. A microcatheter set was used in 12 and a snare technique in four patients. Stricture cannulation failed in the remaining three patients, who finally underwent surgical revision.
Most technical failures using a conventional technique for biliary stricture cannulation after LDLT can be overcome by using a microcatheter set or a snare (rendezvous) technique.
Living donor liver transplantation; Biliary complications; Endoscopy; Fluoroscopy
To assess the role of clusterin in retinal vascular development and in free radical damage in vivo and in vitro.
The expression of clusterin, von Willebrand factor (vWF), flk‐1, heat shock protein 27 (Hsp27) and heat shock protein 70 (Hsp70) was examined in the retinas of developing mice and oxygen‐induced retinopathy (OIR) mice by immunofluorescence staining and western blot analysis. Hydrogen peroxide (H2O2)‐pretreated human retinal endothelial cells (HREC) and astrocytes were cultured in the presence or absence of exogenous clusterin, and then the cell viability was measured using the MTT assay and DAPI staining.
Clusterin was expressed mainly in the inner retina and co‐localised with vWF, an endothelial cell marker. During the mouse developmental process, clusterin expression was decreased, which was similar to the expression of flk‐1, vWF and Hsp27. Furthermore, in the OIR model, clusterin expression changed in a similar way to both vWF and Hsp27. Under hypoxic conditions, clusterin expression increased in HREC and astrocytes. In H2O2‐pretreated HREC and astrocytes, clusterin protected against apoptotic cell death.
These results suggest that clusterin is associated with protection from apoptotic retinal cell death in retinal development and in free radical damage.
Though melatonin was known to regulate gap junctional intercellular communication (GJIC) in chick astrocytes and mouse hepatocytes, the underlying mechanism by melatonin was not elucidated in hydrogen peroxide- (H2O2-) treated HaCaT keratinocyte cells until now. In the current study, though melatonin at 2 mM and hydrogen peroxide (H2O2) at 300 μM showed weak cytotoxicity in HaCaT keratinocyte cells, melatonin significantly suppressed the formation of reactive oxygen species (ROS) in H2O2-treated HaCaT cells compared to untreated controls. Also, the scrape-loading dye-transfer assay revealed that melatonin enhances the intercellular communication by introducing Lucifer Yellow into H2O2-treated cells. Furthermore, melatonin significantly enhanced the expression of connexin 26 (Cx26) and connexin 43 (Cx43) at mRNA and protein levels, but not that of connexin 30 (Cx30) in H2O2-treated HaCaT cells. Of note, melatonin attenuated the phosphorylation of extracellular signal-regulated protein kinases (ERKs) more than p38 MAPK or JNK in H2O2-treated HaCaT cells. Conversely, ERK inhibitor PD98059 promoted the intercellular communication in H2O2-treated HaCaT cells. Furthermore, combined treatment of melatonin (200 μM) and vitamin C (10 μg/mL) significantly reduced ROS production in H2O2-treated HaCaT cells. Overall, these findings support the scientific evidences that melatonin facilitates gap junctional intercellular communication in H2O2-treated HaCaT keratinocyte cells via inhibition of connexin 26/43 and ERK as a potent chemopreventive agent.
Heat shock protein 47 (Hsp47) is a well-known molecular chaperone in collagen synthesis and maturation. The aim of this study is to investigate its putative role in the transdifferentiation of Tenon’s fibroblasts to myofibroblasts.
Primary cultured human Tenon’s fibroblasts were exposed to transforming growth factor-β1 (TGF-β1) for up to 48 hours. The mRNA levels of Hsp47 and α smooth muscle actin (αSMA) were determined by quantitative real time RT-PCR. After delivery of small interfering RNA (siRNA) molecules targeting Hsp47 into the cells, the expression of Hsp47 and αSMA proteins was determined by western immunoblotting.
TGF-β1 increased the mRNA expressions of both Hsp47 and αSMA in human Tenon’s fibroblasts, as determined by quantitative real time RT-PCR. However, it induced the protein expression of only αSMA but not Hsp47, as determined by western immunoblots. When siRNAs specific for Hsp47 were introduced into those cells, the TGF-β1-induced expression of αSMA was significantly attenuated on western immunoblots; after 48 hours of exposure to TGF-β1, the relative densities of immunobands were 11.58 for the TGF-β1 only group and 2.75 for the siRNA treatment group, compared with the no treatment control group (p < 0.001).
Our data suggest that Hsp47 may be related to the TGF-β1-induced transdifferentiation of human Tenon’s fibroblasts to myofibroblasts.
Fibroblast; Fibrosis; Heat shock protein; Myofibroblast; Transforming growth factor-β
Vascular endothelial growth factor (VEGF) is a major regulator in retinal and choroidal angiogenesis, which are common causes of blindness in all age groups. Recently anti-VEGF treatment using anti-VEGF antibody has revolutionarily improved the visual outcome in patients with vaso-proliferative retinopathies. Herein, we demonstrated that bevacizumab as an anti-VEGF antibody could inhibit differentiation of retinoblastoma cells without affection to cellular viability, which would be mediated via blockade of extracellular signal-regulated kinase (ERK) 1/2 activation. The retinoblastoma cells expressed VEGFR-2 as well as TrkA which is a neurotrophin receptor associated with differentiation of retinoblastoma cells. TrkA in retinoblastoma cells was activated with VEGF treatment. Interestingly even in the concentration of no cellular death, bevascizumab significantly attenuated the neurite formation of differentiated retinoblastoma cells, which was accompanied by inhibition of neurofilament and shank2 expression. Furthermore, bevacizumab inhibited differentiation of retinoblastoma cells by blockade of ERK 1/2 activation. Therefore, based on that the differentiated retinoblastoma cells are mostly photoreceptors, our results suggest that anti-VEGF therapies would affect to the maintenance or function of photoreceptors in mature retina.
Upper gastrointestinal (GI) bleeding is a serious complication that sometimes occurs after percutaneous radiologic gastrostomy (PRG). We evaluated the incidence of bleeding complications after a PRG and its management including transcatheter arterial embolization (TAE).
Materials and Methods
We retrospectively reviewed 574 patients who underwent PRG in our institution between 2000 and 2010. Eight patients (1.4%) had symptoms or signs of upper GI bleeding after PRG.
The initial presentation was hematemesis (n = 3), melena (n = 2), hematochezia (n = 2) and bloody drainage through the gastrostomy tube (n = 1). The time interval between PRG placement and detection of bleeding ranged from immediately after to 3 days later (mean: 28 hours). The mean decrease in hemoglobin concentration was 3.69 g/dL (range, 0.9 to 6.8 g/dL). In three patients, bleeding was controlled by transfusion (n = 2) or compression of the gastrostomy site (n = 1). The remaining five patients underwent an angiography because bleeding could not be controlled by transfusion only. In one patient, the bleeding focus was not evident on angiography or endoscopy, and wedge resection including the tube insertion site was performed for hemostasis. The other four patients underwent prophylactic (n = 1) or therapeutic (n = 3) TAEs. In three patients, successful hemostasis was achieved by TAE, whereas the remaining one patient underwent exploration due to persistent bleeding despite TAE.
We observed an incidence of upper GI bleeding complicating the PRG of 1.4%. TAE following conservative management appears to be safe and effective for hemostasis.
Percutaneous radiologic gastrostomy; Bleeding; Transcatheter arterial embolization
To evaluate the safety and effectiveness of a 20-mm diameter dual-design expandable colorectal stent for malignant colorectal obstruction.
Materials and Methods
The study series included 34 patients with malignant colorectal obstruction who underwent implantation of a 20-mm dual-design expandable colorectal stent in our department between March 2009 and June 2010. The 20-mm dual-design expandable colorectal stent was placed by using a 3.8-mm delivery system that had 28-mm diameter proximal and distal ends. Among the 34 patients, stent placement for palliation was performed in 20 patients, while stent placement for bridge to surgery was performed in 14 patients.
A 97% (33 of 34) success rate was achieved for the stent placement. The perforation rate in the bridge to surgery group was 7% (1 of 14), compared to 0% (0 of 19) in palliative group. Migration occurred in one of 33 patients (3%) at 30 days after stent placement.
The placement of a 20-mm diameter dual-design stent appears to be clinically safe and effective for the management of colorectal obstruction, with low perforation and migration rates.
Colorectal cancer; Stent; Dual-design; Expandable
Cancer-associated retinopathy is a paraneoplastic retinal degeneration which may primarily result from auto-immune mediated apoptosis. It has been hypothesized that high titer of auto-antibodies are able to cross the blood-retinal barrier (BRB) and to enter retinal cells to activate apoptotic pathway which has been already well-established. However, it still remains to be elucidated whether auto-antibodies could cross BRB in the retina. Herein, we demonstrated that intravenously administrated anti-recoverin antibodies could not pass through BRB and not lead to retinal cell death.
Anti-recoverin antibody was intravenously injected to C57BL/6 mice, which were sacrificed 1 and 7 days to obtain eye. Vascular endothelial growth factor was intravitreally injected to induce BRB breakdown, which was confirmed by fluorescein angiography and western blotting for zonula occludens (ZO)-1, ZO-2 and occludin. To investigate the location of anti-recoverin antibody in the retina, immunofluorescein was performed. The retinal toxicity of intravenous anti-recoverin antibody was evaluated by histological examination and transferase-mediated dUTP nick-end labeling. Immunofluorescein staining for glial fibrillary acidic protein was done to address glial activation as well.
Intravenously administrated anti-recoverin antibodies were exclusively distributed on retinal vessels which were co-localized with CD31, and led to neither increase of glial fibrillary acidic protein expression, as an indicator of retinal stress, nor apoptotic retinal cell death. Moreover, even in the condition of vascular endothelial growth factor-induced BRB breakdown, anti-recoverin antibodies could not migrate across BRB and still remained on retinal vessels without retinal cytotoxicity.
Our results suggest that high titer of intravascular anti-recoverin antibodies could not penetrate into the retina by themselves, and BRB breakdown mediated by dysregulation of tight junction might not be sufficient to allow anti-recoverin antibodies to pass through BRB.
Anti-recoverin antibody; Blood-retinal barrier; Cancer-associated retinopathy; Intravenous administration; Retina
Clusterin is a secretory glycoprotein, which is highly up-regulated in a variety of normal and injury tissues undergoing apoptosis including infarct region of the myocardium. Here, we report that clusterin protects H9c2 cardiomyocytes from H2O2-induced apoptosis by triggering the activation of Akt and GSK-3β. Treatment with H2O2 induces apoptosis of H9c2 cells by promoting caspase cleavage and cytochrome c release from mitochondria. However, co-treatment with clusterin reverses the induction of apoptotic signaling by H2O2, thereby recovers cell viability. The protective effect of clusterin on H2O2-induced apoptosis is impaired by PI3K inhibitor LY294002, which effectively suppresses clusterin-induced activation of Akt and GSK-3β. In addition, the protective effect of clusterin is independednt on its receptor megalin, because inhibition of megalin has no effect on clusturin-mediated Akt/GSK-3β phosphoylation and H9c2 cell viability. Collectively, these results suggest that clusterin has a role protecting cardiomyocytes from oxidative stress and the Akt/GSK-3β signaling mediates anti-apoptotic effect of clusterin.
apoptosis; clusterin; glycogen synthase kinase 3β; myocytes, cardiac; oxidative stress; proto-oncogene proteins c-akt
Benign strictures of the esophagus and gastric outlet are difficult to manage conservatively and they usually require intervention to relieve dysphagia or to treat the stricture-related complications. In this article, authors review the non-surgical options that are used to treat benign strictures of the esophagus and gastric outlet, including balloon dilation, temporary stent placement, intralesional steroid injection and incisional therapy.
Benign esophageal strictures; Benign gastric-outlet strictures; Interventional procedure; Fluoroscopy; Endoscopy
Despite curative resection, hepatic recurrences cause a significant reduction in survival in patients with primary pancreatic adenocarcinoma. Transcatheter arterial chemoembolization (TACE) has recently been used successfully to treat primary and secondary hepatic malignancy.
Between 2003 and 2008, 15 patients underwent TACE because of hepatic recurrence after curative resection of a pancreatic adenocarcinoma. The tumor response was evaluated based on computed tomography scans after TACE. The overall duration of patient survival was measured.
After TACE, a radiographically evident response occurred in six patients whose tumors demonstrated a tumor blush on angiography. Four patients demonstrated stabilization of a hypovascular mass. The remaining five patients demonstrated continued progression of hypovascular hepatic lesions. The median survival periods from the time of diagnosis and from the time of initial TACE were 9.6 and 7.5 months, respectively.
TACE may represent a viable therapeutic modality in patients with hepatic recurrence after curative resection of pancreatic adenocarcinoma.
Pancreatic adenocarcinoma; Transcatheter arterial chemoembolization; Liver
Unresectable malignant gastric outlet obstruction (GOO) severely affects the quality of life, with complications that include nausea, vomiting, aspiration, pain, and malnutrition. Although palliative surgical procedures have been traditionally performed, they are associated with high morbidity and mortality rates. Placing self-expandable metallic stents is associated with higher clinical success rates, lower morbidity, shorter time from the procedure to starting oral intake, lower incidence of delayed gastric emptying, and a shorter hospital stay than palliative surgery. Fluoroscopic or endoscopic placement of either bare or covered self-expandable metallic stents is a safe, nonsurgical, palliative treatment option for unresectable malignant GOOs, with a high clinical success rate and a low rate of serious complications. Stent obstruction and migration are the most common complications, but most can be managed by interventional treatments. Although there have been substantial developments in stent design over the past decade, large prospective, randomized studies are required to determine the ideal stent for malignant GOOs.
Malignant gastric outlet obstruction; Palliative treatment; Placement of a self-expandable metallic stent; Endoscopy; Fluoroscopy
To evaluate the clinical and radiological outcomes of transcatheter embolotherapy for treating sporadic pulmonary arteriovenous malformations (PAVMs) that were not associated with hereditary hemorrhagic telangiectasia.
Materials and Methods
Between January 2001 and June 2008, thirty-five sporadic PAVMs were detected in 23 patients. The clinical follow up consisted of assessing the changes of the signs and symptoms of the PAVMs, and radiological evaluation with chest radiographs or chest CT scans.
The lower lung regions (63%) and peripheral locations (86%) were the common locations of the PAVMs. Thirty-four PAVMs (97%) had simple architecture (one arterial feeder within a single pulmonary segment). Technical success was achieved in 33 PAVMs (94%); two cases of technical failure were due to catheterization failure (n = 1) and too large a feeding artery (17 mm) that disabled embolotherapy (n = 1). Coils and Amplatz vascular plugs were used in 30 and three PAVMs, respectively. Inadvertent placement of one coil (n = 1) and pulmonary infarction (n = 1) occurred, but no relevant symptoms developed. For the 13 patients with available data, the mean arterial O2 saturation changed significantly from 92% to 98%. Complete or near-complete involution of the sac was observed in 30 of the 33 embolized PAVMs (91%). In these 33 embolized PAVMs, the mean sac diameter significantly decreased from 17.83 mm to 0.68 mm.
Sporadic PAVMs are mostly the simple type with predominance in the lower lobe and peripheral locations. Transcatheter embolotherapy with coils or Amplatz vascular plugs is a safe and effective treatment for sporadic PAVMs and this provides excellent functional and radiological improvement.
Pulmonary arteriovenous malformation; Hereditary hemorrhagic telangiectasia; Embolotherapy; Amplatz vascular plug
An esophagorespiratory fistula (ERF) is an often fatal consequence of esophageal or bronchogenic carcinomas. The preferred treatment is placement of esophageal and/or airway stents. Stent placement must be performed as quickly as possible since patients with ERFs are at a high risk for aspiration pneumonia. In this review, choice of stents and stenting area, fistula reopening and its management, and the long-term outcome in the interventional management of malignant ERFs are considered. Lastly, a review of esophagopulmonary fistulas will also be provided.
Interventional technique; Esophagorespiratory fistula; Esophagopleural fistula
To investigate the relationship between vascular endothelial growth factor (VEGF) and the cancer stem cell-vascular niche complex in human retinoblastoma tissue.
Six human retinoblastoma specimens primarily enucleated for Reese-Ellsworth classification stage 5a were stained to detect cancer stem cell markers, including ABCG2 for the stem cell marker and MCM2 for the neural stem cell marker, as well as to detect VEGF for the angiogenic cytokine. Using immunofluorescence, the expression of these proteins was analyzed, and their relative locations noted.
In non-neoplastic retina of tumor-bearing eyes, ABCG2 and MCM2 were sporadically expressed in the ganglion cell layer and the inner nuclear layer, whereas VEGF was sporadically expressed in inner retina where retinal vessels are abundantly distributed. In the tumor, ABCG2 was strongly expressed out of Wintersteiner rosettes, whereas MCM2 and VEGF were strongly stained in the rosettes. Interestingly, the outer portion of the rosettes was positive for MCM2, and the inner portion of the rosettes was positive for VEGF.
Our data demonstrated that MCM2 and VEGF are strongly expressed in the rosettes of the tumor, which were far from the area of ABCG2-positive cells. Although VEGF might not directly contribute to the cancer stem cell-vascular niche complex, it could play some role in the differentiation of tumor cells to build up the rosettes.
Biological tumor markers; Neoplastic stem cells; Retinoblastoma; Vascular endothelial growth factors
To evaluate the incidence, predictive factors, and clinical outcomes of angiographically negative acute arterial upper and lower gastrointestinal (GI) bleeding.
Materials and Methods
From 2001 to 2008, 143 consecutive patients who underwent an angiography for acute arterial upper or lower GI bleeding were examined.
The angiographies revealed a negative bleeding focus in 75 of 143 (52%) patients. The incidence of an angiographically negative outcome was significantly higher in patients with a stable hemodynamic status (p < 0.001), or in patients with lower GI bleeding (p = 0.032). A follow-up of the 75 patients (range: 0-72 months, mean: 8 ± 14 months) revealed that 60 of the 75 (80%) patients with a negative bleeding focus underwent conservative management only, and acute bleeding was controlled without rebleeding. Three of the 75 (4%) patients underwent exploratory surgery due to prolonged bleeding; however, no bleeding focus was detected. Rebleeding occurred in 12 of 75 (16%) patients. Of these, six patients experienced massive rebleeding and died of disseminated intravascular coagulation within four to nine hours after the rebleeding episode. Four of the 16 patients underwent a repeat angiography and the two remaining patients underwent a surgical intervention to control the bleeding.
Angiographically negative results are relatively common in patients with acute GI bleeding, especially in patients with a stable hemodynamic status or lower GI bleeding. Most patients with a negative bleeding focus have experienced spontaneous resolution of their condition.
Upper gastrointestinal bleeding; Lower gastrointestinal bleeding; Angiography
The retinal activity for vision requires a precise synaptic connectivity. Shank proteins at postsynaptic sites of excitatory synapses play roles in signal transmission into the postsynaptic neuron. However, the correlation of Shank 2 expression with neuronal differentiation in the developing retina remains to be elucidated regardless of previous evidences of Shank 2 expression in retina. Herein, we demonstrated that with progression of development, Shank 2 is initially detected in the inner plexiform layer at P2, and then intensively detected in inner plexiform layer, outer plexiform layer, and ganglion cell layer at P14, which was closely colocalized to the neurofilament expression. Shank 2 was, however, not colocalized with glial fibrillary acidic protein. Shank 2 expression was increased in the differentiated retinoblastoma cells, which was mediated by ERK 1/2 activation. Moreover, Shank 2 expression was colocalized with neurofilament at the dendritic region of cells. In conclusion, our data suggests that Shank 2 is expressed in the neurons of the developing retina and could play a critical role in the neuronal differentiation of the developing retina.
cell differentiation; extracellular signal-regulated MAP kinases; neurons; retina; SHANK 2 protein, human
Pathologic angiogenesis in the retina leads to the catastrophic loss of vision. Retinopathy of prematurity (ROP), a vasoproliferative retinopathy, is a leading cause of blindness in children. We evaluated the inhibitory effect of decursin on retinal neovascularization.
Anti-angiogenic activity of decursin was evaluated by vascular endothelial growth factor (VEGF)-induced proliferation, migration, and in vitro tube formation assay of human retinal microvascular endothelial cells (HRMECs). We also used western blot analysis to assess inhibition of vascular endothelial growth factor receptor-2 (VEGFR-2) phosphorylation by decursin. After intravitreal injection of decursin in a mouse model of ROP, retinal neovascularization was examined by fluorescence angiography and vessel counting in cross-sections. The toxicity of decursin was evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in HRMECs as well as histologic and immunohistochemistry examination for glial fibrillary acidic protein in the retina.
Decursin significantly inhibited VEGF-induced proliferation, migration, and the formation of capillary-like networks of retinal endothelial cells in a dose-dependent manner. Decursin inhibited VEGF-induced phosphorylation of VEGFR-2, blocking the VEGFR-2 signaling pathway. When intravitreously injected, decursin dramatically suppressed retinal neovascularization in a mouse model of ROP. Even in a high concentration, decursin never induced any structural or inflammatory changes to cells in retinal or vitreous layers. Moreover, the upregulation of glial fibrillary acidic protein expression was not detected in Mueller cells.
Our data suggest that decursin may be a potent anti-angiogenic agent targeting the VEGFR-2 signaling pathway, which significantly inhibits retinal neovascularization without retinal toxicity and may be applicable in various other vasoproliferative retinopathies as well.
A benign anastomotic stricture is a common complication of upper gastrointestinal (UGI) surgery and is difficult to manage conservatively. Fluoroscopically guided balloon dilation has a number of advantages and is a safe and effective procedure for the treatment of various benign anastomotic strictures in the UGI tract.
Gastrointestinal tract, interventional procedures; Stomach, interventional procedures; Esophagus, interventional procedures; Stomach, stenosis or obstruction; Esophagus, stenosis or obstruction
Age-related macular degeneration (AMD) is the leading cause of blindness in elderly. The detailed mechanism of choroidal neovascularization (CNV) leads to severe vision loss in patients with AMD. This study was undertaken to evaluate the inhibitory effect of homoisoflavanone on CNV.
Antiangiogenic activity of homoisoflavanone was evaluated by in vitro tube formation assay of human umbilical vein endothelial cells (HUVECs) and cell migration assay of HUVECs., Homoisoflavanone or PBS was injected intravitreously into a mouse model of laser-photocoagulation-induced CNV. Fluorescein angiography and vessel counting in cross sections were employed to examine CNV lesions. The toxicity of homoisoflavanone was evaluated through 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT) assay in HUVECs as well as histological examination and terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining in the retina.
Homoisoflavanone effectively inhibited in vitro tube formation and cell migration of HUVECs. Interestingly, homoisoflavanone significantly reduced CNV and its leakage in a mouse model of laser-photocoagulation-induced CNV. In addition, homoisoflavanone showed no effect on cell viability of HUVECs and no retinal toxicity in a concentration range of 1-10 μM.
Our data suggest that homoisoflavanone is a potent inhibitor of CNV and may be applied in the treatment of other vasoproliferative retinopathies and tumor.
Control of currently circulating re-assorted low-pathogenicity avian influenza (LPAI) H9N2 is a major concern for both animal and human health. Thus, an improved LPAI H9N2 vaccination strategy is needed to induce complete immunity in chickens against LPAI H9N2 virus strains. Cytokines play a crucial role in mounting both the type and extent of an immune response generated following infection with a pathogen or after vaccination. To improve the efficacy of inactivated LPAI H9N2 vaccine, attenuated Salmonella enterica serovar Typhimurium was used for oral co-administration of chicken interferon-α (chIFN-α) and chicken interleukin-18 (chIL-18) as natural immunomodulators.
Oral co-administration of S. enterica serovar Typhimurium expressing chIFN-α and chIL-18, prior to vaccination with inactivated AI H9N2 vaccine, modulated the immune response of chickens against the vaccine antigen through enhanced humoral and Th1-biased cell-mediated immunity, compared to chickens that received single administration of S. enterica serovar Typhimurium expressing either chIFN-α or chIL-18. To further test the protective efficacy of this improved vaccination regimen, immunized chickens were intra-tracheally challenged with a high dose of LPAI H9N2 virus. Combined administration of S. enterica serovar Typhimurium expressing chIFN-α and chIL-18 showed markedly enhanced protection compared to single administration of the construct, as determined by mortality, clinical severity, and feed and water intake. This enhancement of protective immunity was further confirmed by reduced rectal shedding and replication of AIV H9N2 in different tissues of challenged chickens.
Our results indicate the value of combined administration of chIFN-α and chIL-18 using a Salmonella vaccine strain to generate an effective immunization strategy in chickens against LPAI H9N2.
Attenuated Salmonella vaccine; Chicken interferon-α; Chicken interleukin-18; Avian influenza H9N2; Oral delivery