Inflammatory myofibroblastic tumor of the nasal cavity

Inflammatory myofibroblastic tumor (IMT) is a rare tumor with a variable natural history and biologic behavior, ranging from completely benign to malignant with fatal outcome. We report a case of benign IMT in the left nasal cavity with radiologic features mimicking angiofibroma. We also demonstrate the hypervascular nature of this disease on angiography and the contribution of preoperative embolization in assisting surgical excision and minimizing the potential uncontrolled intraoperative bleeding.     

Roles of Neutrophil Gelatinase-Associated Lipocalin in Continuous Ambulatory Peritoneal Dialysis-Related Peritonitis

Introduction  We measured the neutrophil gelatinase-associated lipocalin (NGAL) concentration in peritoneal dialysate effluent (PDE) collected following an acute episode of continuous ambulatory peritoneal dialysis (CAPD)-related peritonitis. Results  NGAL concentration in PDE increased in the first 3 days after developing peritonitis and correlated well with the neutrophil count. In patients with culture-negative peritonitis, the NGAL in PDE was lower than that in patients with gram-positive or gram-negative peritonitis. Apart from providing additional diagnostic support to bacterial-induced peritonitis, measurement of NGAL in PDE may be useful to differentiate the neutrophil-dependent culture-negative peritonitis from that associated with non-bacterial or non-cellular etiologies. Conclusion  Human peritoneal mesothelial cell (HPMC) is another source of NGAL during peritonitis. NGAL was specifically induced in HPMC by IL-1β. Incubation of HPMC with recombinant NGAL reversed the transforming growth factor-β-induced up-regulation of Snail and vimentin but rescued the down-regulation of E-cadherin. Our data suggest that NGAL may exert a protective effect in modulating the epithelial-to-mesenchymal transition activated following peritonitis.     

Surface Mucin-1 does not play a role in dendritic cell migration

Mucin-1 (MUC1) is a transmembrane glycoprotein that is upregulated upon maturation of dendritic cells (DC) in vitro or in vivo. One of the proposed functions of surface expressed MUC1 is its involvement in migration of cells. We hypothesized that MUC1 is involved in DC migration since mature DC (mDC) are highly migratory cells and MUC1 is upregulated on the surface of DC upon maturation. In this study we cultured DC using two maturation cocktails, one cocktail containing IL-4, GM-CSF, TNFalpha, PGE2, IL-1 beta and IL-6 (TP1,6-DC) and the other IL-13, GM-CSF, Ribomunyl and IFN-gamma (RI-DC). Both maturation cocktails render DC with a similar surface phenotype including CCR7 expression, but only the former induces a migratory capacity of DC to a CCL19 gradient. To analyze the role of surface-expression of MUC1 on TP1,6-DC, that are capable of migration, expression of MUC1 was prevented by adding an anti-MUC1 antibody (Ab) during the maturation process. Compared with matured DC in the absence of the Ab, no difference was observed in chemokine-induced migratory behaviour between the MUC1+ and MUC1- DC populations in a standard Transwell chemotaxis assay, nor in organotypic cultures. Our data clearly demonstrate that surface MUC1 on DC does not influence intrinsic cell-motility, nor is it involved in cell-cell and cell-matrix dependent migration.     

Microfeature guided skeletal muscle tissue engineering for highly organized 3-dimensional free-standing constructs

Engineering tissue similar in structure to their natural equivalents is a major challenge and crucial to function. Despite attempts to engineer skeletal muscle, it is still difficult to effectively mimic tissue architecture. Rigid scaffolds can guide cell alignment but have the critical drawback of hindering mechanical function of the resultant tissue. We present a method for creating highly ordered tissue-only constructs by using rigid microtopographically patterned surfaces to first guide myoblast alignment, followed by transfer of aligned myotubes into a degradable hydrogel and self-organization of the ordered cells into a functional, 3-dimensional, free-standing construct independent of the initial template substrate. Histology revealed an intracellular organization resembling that of native muscle. Aligned cell constructs exhibited a 2-fold increase in peak force production compared to controls. Effective specific force, or force normalized over cross-sectional area, was increased by 23%. This template, transfer, and self-organization strategy is envisioned to be broadly useful in improving construct function and clinical applicability for highly ordered tissues like muscle.     

Biological performance of a polycaprolactone-based scaffold used as fusion cage device in a large animal model of spinal reconstructive surgery

A bioactive and bioresorbable scaffold fabricated from medical grade poly (epsilon-caprolactone) and incorporating 20% beta-tricalcium phosphate (mPCL–TCP) was recently developed for bone regeneration at load bearing sites. In the present study, we aimed to evaluate bone ingrowth into mPCL–TCP in a large animal model of lumbar interbody fusion. Six pigs underwent a 2-level (L3/4; L5/6) anterior lumbar interbody fusion (ALIF) implanted with mPCL–TCP + 0.6 mg rhBMP-2 as treatment group while four other pigs implanted with autogenous bone graft served as control. Computed tomographic scanning and histology revealed complete defect bridging in all (100%) specimen from the treatment group as early as 3 months. Histological evidence of continuing bone remodeling and maturation was observed at 6 months. In the control group, only partial bridging was observed at 3 months and only 50% of segments in this group showed complete defect bridging at 6 months. Furthermore, 25% of segments in the control group showed evidence of graft fracture, resorption and pseudoarthrosis. In contrast, no evidence of graft fractures, pseudoarthrosis or foreign body reaction was observed in the treatment group. These results reveal that mPCL–TCP scaffolds could act as bone graft substitutes by providing a suitable environment for bone regeneration in a dynamic load bearing setting such as in a porcine model of interbody spine fusion.     

Leptin Signaling Protects NK Cells from Apoptosis During Development in Mouse Bone Marrow

Increasing evidence indicates a role of leptin in immune response, but it remains largely unclear whether leptin signaling is involved in regulating NK cell development in the bone marrow （BM）. In this study, we have characterized NK cell differentiation and maturation in the BM of leptin-receptor deficient db/db mice at a prediabetic stage. Although the BM cellularity was similar to the control value, the total number of NK cells was severely reduced in mutant mice. Flow cytometric analysis of db/db BM cells revealed significantly decreased frequencies of developing NK cells at various stages of differentiation. BM db/db NK cells displayed markedly increased apoptosis but maintained normal cell cycling status and proliferative capacity. Moreover, recombinant leptin could significantly enhance the survival of NK cells from wild-type mice in cultures. Further examination on NK cell functional activity showed that db/db NK cells exhibited normal intrinsic cytotoxicity with significantly increased IL-10 production. Taken together, our findings suggest that leptin signaling regulates NK cell development via enhancing the survival of immature NK cells in mouse BM.     

Salmonella enterica Serovar Enteritidis Pathogenicity Island 1 Is Not Essential for but Facilitates Rapid Systemic Spread in Chickens

Salmonella enterica subsp. enterica serovar Enteritidis is a leading cause of human food-borne illness that is mainly associated with the consumption of contaminated poultry meat and eggs. To cause infection, S. Enteritidis is known to use two type III secretion systems, which are encoded on two salmonella pathogenicity islands, SPI-1 and SPI-2, the first of which is thought to play a major role in invasion and bacterial uptake. In order to study the role of SPI-1 in the colonization of chicken, we constructed deletion mutants affecting the complete SPI-1 region (40 kb) and the invG gene. Both ΔSPI-1 and ΔinvG mutant strains were impaired in the secretion of SipD, a SPI-1 effector protein. In vitro analysis using polarized human intestinal epithelial cells (Caco-2) revealed that both mutant strains were less invasive than the wild-type strain. A similar observation was made when chicken cecal and small intestinal explants were coinfected with the wild-type and ΔSPI-1 mutant strains. Oral challenge of 1-week-old chicken with the wild-type or ΔSPI-1 strains demonstrated that there was no difference in chicken cecal colonization. However, systemic infection of the liver and spleen was delayed in birds that were challenged with the ΔSPI-1 strain. These data demonstrate that SPI-1 facilitates systemic infection but is not essential for invasion and systemic spread of the organism in chickens.Salmonella enterica is a gram-negative enteropathogenic bacterium. Within the S. enterica species, more than 2,300 serovars have been identified, of which the serovars Enteritidis and Typhimurium have been the most frequently associated with human infections (49). S. Enteritidis is a well-known zoonotic pathogen (30), and infected poultry are among the most common reservoir of salmonellae that can be transmitted through the food chain to humans (18). In young chicks, S. Enteritidis infection can lead to increased incidence of illness, while older birds are less susceptible to the effects of this pathogen, often experiencing intestinal colonization and even systemic dissemination without significant morbidity or mortality. Hence, a better understanding of the pathogenesis of S. Enteritidis in chickens may subsequently lower the rates of human disease caused by this pathogen.S. Enteritidis requires a substantial number of genes for virulence, which are clustered in large chromosomal regions known as Salmonella pathogenicity islands (SPI) (40). Two of these pathogenicity islands encode two functionally distinct type III secretion systems (T3SS) that are utilized as “molecular syringes” to translocate virulence determinants, called effector proteins, from the bacterial cytoplasm into (29, 30) or in the vicinity of the target cell (52). Effector proteins delivered by the SPI-1 T3SS are mainly involved in host cell invasion by inducing membrane ruffling and disrupting actin polymerization to facilitate bacterial uptake (17). The SPI-2 T3SS plays a major role in systemic virulence and in facilitating intracellular survival, especially within macrophages. However, recent evidence suggests that the SPI-2 T3SS also plays a role in intestinal colonization (10, 11) and is expressed prior to bacterial uptake (6).Invasion of epithelial cells by Salmonella enterica subspecies enterica serovar Typhimurium has been shown to disrupt tight junctions (15, 31, 54) which, along with other components, form important intercellular junctions found in polarized epithelial cells. Tight junctions regulate the paracellular flow of ions and solutes across the intestinal epithelium. They also maintain distinct apical and basolateral domains with well-defined plasma membrane components (42). SPI-1 effector proteins have been associated with the disruption of tight junctions (5, 31, 54) by activating Cdc42 and Rac-1 (Rho family GTPases), which subsequently activate signal transduction pathways that lead to the reorganization of actin, resulting in the uptake of Salmonella (45). Further, the S. Typhimurium SPI-1 effectors SopB, SopE, SopE2, and SipA have been identified as major contributors in the disruption of tight junctions (5).The contribution of S. Typhimurium SPI-1 to intestinal cell invasion has been studied in cell culture using different SPI-1 deletion mutants. SPI-1 regulatory gene hilA and sipB (SPI-1 effector gene) mutants have been shown to be attenuated in invasion relative to the wild-type strain in porcine intestinal epithelioid (IPI-21) cells. However, the use of polarized porcine intestinal epithelial cells (IPEC-J2) has revealed that, in addition to hilA and sipB mutant strains, a sipA (SPI-1 effector gene) mutant strain was also recovered at a significantly lower rate than the wild-type strain (4), suggesting that SPI-1 is important for efficient invasion. In another study, it was demonstrated that the S. Typhimurium SPI-1 effectors SipA, SopA, SopB, SopD, and SopE2 all contributed to invasion of polarized human colon carcinoma cells (T84). Mutants lacking the genes for the aforementioned effector proteins were less invasive than the wild-type strain (51). Moreover, an S. Typhimurium strain lacking the invG gene (encoding an outer membrane component of the SPI-1 T3SS apparatus) was also impaired in invasion of COS-7 cells (24). Taken together, the results from these invasion studies suggest that SPI-1 plays a role in invasion in cell culture. However, most of the data available is from research that has been conducted using S. Typhimurium.Several in vivo experiments have been performed to investigate the role of SPI-1 during the course of a Salmonella infection in different animal species using deletion mutants in SPI-1 genes. In the murine model of infection, it was observed that S. Typhimurium strains containing mutations in hilA and invG were recovered from intestinal contents and systemic sites at a lower frequency than the wild-type strain (43). Other groups have reported that a functional SPI-1 T3SS is required to induce intestinal inflammation and cause significant histopathological changes in the streptomycin-treated mouse model of infectious enterocolitis (1, 10, 24). Similarly, in the bovine model of enteritis, SPI-1 has been shown to be important for intestinal colonization (20). In addition, it has been demonstrated that S. Typhimurium SPI-1 gene (sipA, sipB, and hilA) mutants were impaired in their ability to colonize the porcine gut in a ligated intestinal loop model (4). However, a recent study has shown that a SPI-1 functional mutant induces intestinal pathology that is very similar to the wild-type strain when studied 5 days postchallenge in a novel bovine ileal loop model (11).Studies investigating the contribution of SPI-1 in chicken during the course of an S. Enteritidis infection are limited in number and have mostly observed colonization and systemic infection over a short time frame. Infection of 1-day-old birds with S. Enteritidis strains containing mutations in the invA, invB, and invC genes (SPI-1 genes) has shown that these organisms are attenuated in the colonization of the gastrointestinal tract, as well as in the systemic spread of the organism over a period of 6 days postinfection (48). In another study, it was observed that S. Enteritidis sipD mutants were unable to colonize spleens compared to the wild-type strain 3 days postinfection in 1-day-old chicks (44). However, the colonization of the spleen was only measured at one time point, making it difficult to predict the effect of the mutant strain prior to and after, the third day after infection. A similar trend was seen in the ceca of 1-day-old chicks challenged with a S. Enteritidis hilA mutant strain over a period of 28 days postinfection (3). However, the hilA mutant strain did not have a significant impact on the infection of the livers and spleens. Recently, the impact of SPI-1 was examined using a S. Typhimurium spaS mutant strain in 1-day-old and 1-week-old birds (32). Inactivation of spaS (SPI-1 structural protein) did not affect colonization of the livers or ceca of 1-day-old birds over a period of 72 h postinfection. In 1-week-old birds, the same strain was recovered at lower levels from the ceca over a period of 14 days postinfection, while the recovery from the liver was lower at 3 days postinfection (32).Taken together, the experimental evidence from the in vitro studies suggests that S. Typhimurium SPI-1 has an impact on invasion. However, studies investigating the role of S. Enteritidis SPI-1 in vivo are limited. Moreover, research from the murine, bovine, and porcine models of salmonellosis indicates that SPI-1 may play a role in breaching the intestinal epithelial layer during the course of an infection. Nevertheless, little is known about the virulence properties of the S. Enteritidis SPI-1 T3SS in the colonization of chickens. In addition, recent evidence suggests that S. enterica is capable of establishing infection without the presence of SPI-1 (11, 25, 28). The objective of the present study was to investigate the contribution of the S. Enteritidis SPI-1 T3SS in the invasion of polarized Caco-2 cells and chicken intestinal explants and in the colonization of chickens over a period of 4 days postchallenge. Our data indicate that S. Enteritidis SPI-1 is important for invasion in polarized Caco-2 cells and intestinal epithelial cells in vitro. We also show that a ΔSPI-1 mutant strain is not impaired in the cecal colonization of 1-week-old chickens. However, the deletion of the SPI-1 region causes a delay in systemic infection.     

Effect of omeprazole on the pharmacokinetics and toxicities of irinotecan in cancer patients: a prospective cross-over drug-drug interaction study

Background

Omeprazole is one of the most prescribed medications worldwide and within the class of proton pump inhibitors, it is most frequently associated with drug interactions. In vitro studies have shown that omeprazole can alter the function of metabolic enzymes and transporters that are involved in the metabolism of irinotecan, such as uridine diphosphate glucuronosyltransferase subfamily 1A1 (UGT1A1), cytochrome P-450 enzymes subfamily 3A (CYP3A) and ATP-binding cassette drug-transporter G2 (ABCG2). In this open-label cross-over study we investigated the effects of omeprazole on the pharmacokinetics and toxicities of irinotecan.

Methods

Fourteen patients were treated with single agent irinotecan (600 mg i.v., 90 min) followed 3 weeks later by a second cycle with concurrent use of omeprazole 40 mg once daily, which was started 2 weeks prior to the second cycle. Plasma samples were obtained up to 55 h after infusion and analysed for irinotecan and its metabolites 7-ethyl-10-hydroxycampothecin (SN-38), SN-38-glucuronide (SN-38G), 7-ethyl-10-[4-(1-piperidino)-1-amino]-carbonyloxycamptothecin (NPC) and 7-ethyl-10-[4-N-(5-aminopentanoic acid)-1-piperidino]-carbonyloxycamptothecin (APC) by high-performance liquid chromatography (HPLC). Non-compartmental modelling was performed. Toxicities were monitored during both cycles. Paired statistical tests were performed with SPSS.

Results

The exposure to irinotecan and its metabolites was not significantly different between both cycles. Neither were there significant differences in the absolute nadir and percentage decrease of WBC and ANC, nor on the incidence and severity of neutropenia, febrile neutropenia, diarrhoea, nausea and vomiting when irinotecan was combined with omeprazole.

Conclusion

Omeprazole 40 mg did not alter the pharmacokinetics and toxicities of irinotecan. This widely used drug can, therefore, be safely administered during a 3-weekly single agent irinotecan schedule.     

FGF8b oncogene mediates proliferation and invasion of Epstein-Barr virus-associated nasopharyngeal carcinoma cells: implication for viral-mediated FGF8b upregulation

The fibroblast growth factor 8b (FGF8b) oncogene is known to be primarily involved in the tumorigenesis and progression of hormone-related cancers. Its role in other epithelial cancers has not been investigated, except for esophageal cancer, in which FGF8b overexpression was mainly found in tumor biopsies of male patients. These observations were consistent with previous findings in these cancer types that the male sex-hormone androgen is responsible for FGF8b expression. Nasopharyngeal carcinoma (NPC) is a highly metastatic cancer of head and neck commonly found in Asia. It is etiologically associated with Epstein-Barr Virus (EBV) infection, inflammatory tumor microenvironment and relatively higher male predominance. Here, we reported for the first time that FGF8b is overexpressed in this EBV-associated non-hormone-related cancer of the head and neck, NPC. More importantly, overexpression of FGF8b mRNA and protein was detected in a large majority of NPC tumors from both male and female genders, in addition to multiple NPC cell lines. We hypothesized that FGF8b overexpression may contribute to NPC tumorigenesis. Using EBV-associated NPC cell lines, we demonstrated that specific knockdown of FGF8b by small interfering RNA inhibited cell proliferation, migration and invasion, whereas exogenous FGF8b stimulated these multiple phenotypes. Further mechanistic investigation revealed that in addition to NF-κB signaling (a major inflammatory signaling pathway known to be activated in NPC), an important EBV oncoprotein, the latent membrane protein 1 (LMP1), was found to be a direct inducer of FGF8b overexpression in NPC cells, whereas androgen (testosterone) has minimal effect on FGF8b expression in EBV-associated NPC cells. In summary, our study has identified LMP1 as the first viral oncogene capable of directly inducing FGF8b (an important cellular oncogene) expression in human cancer cells. This novel mechanism of viral-mediated FGF8 upregulation may implicate a new role of oncoviruses in human carcinogenesis.