Tight junction defects are seen in the buccal mucosa of patients receiving standard dose chemotherapy for cancer

Oral mucositis is one of the most common and debilitating side effects of chemotherapy treatment. Patients are often unable to eat and drink, which can lead to poor clinical outcomes and extensive resource utilisation. The primary aim of this study was to determine the molecular integrity of oral epithelial tight junctions in patients undergoing chemotherapy. The secondary aim was to correlate these changes with proinflammatory cytokines and matrix metalloproteinase profiles.Patients (n = 23) were recruited from the Royal Adelaide Hospital between 2000 and 2003. Reach patient underwent two oral buccal mucosa biopsies (4 mm): one prior to chemotherapy treatment and a second one after chemotherapy treatment. Oral buccal mucosa biopsies were also taken from seven healthy volunteers with no history of cancer, chemo- or radiotherapy treatment or inflammatory disorders. Routine haematoxylin and eosin staining was performed to determine epithelial thickness. Immunohistochemical staining was performed for claudin-1, zonular occludens-1, occludin, interleukin-1β, tumour necrosis factor, interleukin-6, matrix metalloproteinase-2 and metalloproteinase-9.Patients receiving standard dose chemotherapy had significant epithelial atrophy. Elevations in all cytokines and matrix metalloproteinases were seen, with significant lamina propria staining for interleukin-6 and tumour necrosis factor. Matrix metalloproteinase-2 appeared most upregulated within the oral epithelium. These changes coincided with altered tight junction staining properties. Changes in the staining intensity and localisation were both noted, with clear cytoplasmic staining for zonular occludens-1 and claudin-1 in patients treated with chemotherapy.Chemotherapy causes defects in oral tight junctions, coupled with altered cytokine and matrix metalloproteinase profiles. Tight junction disruption in the epithelium may contribute to ulcer development or lead to poor tissue integrity, and the timing of these events may be a target for preventative treatment.Hannah R. Wardill, Richard M. Logan, Joanne M. Bowen, Ysabella Z. A. Van Sebille, Rachel J. Gibso

A novel in vitro platform for the study of SN38-induced mucosal damage and the development of Toll-like receptor 4-targeted therapeutic options

Tight junction and epithelial barrier disruption is a common trait of many gastrointestinal pathologies, including chemotherapy-induced gut toxicity. Currently, there are no validated in vitro models suitable for the study of chemotherapy-induced mucosal damage that allow paralleled functional and structural analyses of tight junction integrity. We therefore aimed to determine if a transparent, polyester membrane insert supports a polarized T84 monolayer with the phenotypically normal tight junctions. T84 cells (passage 5-15) were seeded into either 0.6 cm(2), 0.4 µm pore mixed-cellulose transwell hanging inserts or 1.12 cm(2), 0.4 µm pore polyester transwell inserts at varying densities. Transepithelial electrical resistance was measured daily to assess barrier formation. Immunofluoresence for key tight junction proteins (occludin, zonular occludens-1, claudin-1) and transmission electron microscopy were performed to assess tight junction integrity, organelle distribution, and polarity. Reverse transcription-polymerase chain reaction was performed to determine expression of toll-like receptor 4 (TLR4). Liquid chromatography was also conducted to assess SN38 degradation in this model. Polyester membrane inserts support a polarized T84 phenotype with functional tight junctions in vitro. Transmission electron microscopy indicated polarity, with apico-laterally located tight junctions. Immunofluorescence showed membranous staining for all tight junction proteins. No internalization was evident. T84 cells expressed TLR4, although this was significantly lower than levels seen in HT29 cells (P = .0377). SN38 underwent more rapid degradation in the presence of cells (-76.04 ± 1.86%) compared to blank membrane (-48.39 ± 4.01%), indicating metabolic processes. Polyester membrane inserts provide a novel platform for paralleled functional and structural analysis of tight junction integrity in T84 monolayers. T84 cells exhibit the unique ability to metabolize SN38 as well as expressing TLR4, making this an excellent platform to study clinically relevant therapeutic interventions for SN38-induced mucosal damage by targeting TLR4.Hannah R Wardill, Rachel J Gibson, Ysabella ZA Van Sebille, Kate R Secombe, Richard M Logan, and Joanne M Bowe

Routine assessment of the gut microbiome to promote preclinical research reproducibility and transparency

Letter. Published online 9 January 2017Hannah R Wardill, Joanne M Bowen, Ysabella ZA Van Sebille, Rachel J Gibso

TLR4-dependent claudin-1 internalization and secretagogue-mediated chloride secretion regulate irinotecan-induced diarrhea

Published OnlineFirst August 22, 2016Abstract not availableHannah R.Wardill, Joanne M. Bowen, Ysabella Z.A. Van Sebille, Kate R. Secombe, Janet K. Coller, Imogen A. Ball, Richard M. Logan, and Rachel J Gibso

Irinotecan-induced gastrointestinal dysfunction and pain are mediated by common TLR4-dependent mechanisms

Published Online First March 29, 2016Abstract not availableHannah R. Wardill, Rachel J. Gibson, Ysabella Z.A. Van Sebille, Kate R. Secombe, Janet K. Coller, Imogen A. White, Jim Manavis, Mark R. Hutchinson, Vasiliki Staikopoulos, Richard M. Logan, and Joanne M. Bowe

Identification of candidate pelagic marine protected areas through a seabird seasonal-, multispecific- and extinction risk-based approach

With increasing pressure on the oceans from environmental change, there has been a global call for improved protection of marine ecosystems through the implementation of marine protected areas (MPAs). Here, we used species distribution modelling (SDM) of tracking data from 14 seabird species to identify key marine areas in the southwest Atlantic Ocean, valuing areas based on seabird species occurrence, seasonality and extinction risk. We also compared overlaps between the outputs generated by the SDM and layers representing important human threats (fishing intensity, ship density, plastic and oil pollution, ocean acidification), and calculated loss in conservation value using fishing and ship density as cost layers. The key marine areas were located on the southern Patagonian Shelf, overlapping extensively with areas of high fishing activity, and did not change seasonally, while seasonal areas were located off south and southeast Brazil and overlapped with areas of high plastic pollution and ocean acidification. Non-seasonal key areas were located off northeast Brazil on an area of high biodiversity, and with relatively low human impacts. We found support for the use of seasonal areas depending on the seabird assemblage used, because there was a loss in conservation value for the seasonal compared to the non-seasonal approach when using ‘cost’ layers. Our approach, accounting for seasonal changes in seabird assemblages and their risk of extinction, identified additional candidate areas for incorporation in the network of pelagic MPAs

The pathogenesis of mucositis: updated perspectives and emerging targets

Published online: 8 July 2019Mucositis research and treatment are a rapidly evolving field providing constant new avenues of research and potential therapies. The MASCC/ISOO Mucositis Study Group regularly assesses available literature relating to pathogenesis, mechanisms, and novel therapeutic approaches and distils this to summary perspectives and recommendations. Reviewers assessed 164 articles published between January 2011 and June 2016 to identify progress made since the last review and highlight new targets for further investigation. Findings were organized into sections including established and emerging mediators of toxicity, potential insights from technological advances in mucositis research, and perspective. Research momentum is accelerating for mucositis pathogenesis, and with this has come utilization of new models and interventions that target specific mechanisms of injury. Technological advances have the potential to revolutionize the field of mucositis research, although focused effort is needed to move rationally targeted interventions to the clinical setting.J. Bowen, N. Al-Dasooqi, P. Bossi, H. Wardill, Y. Van Sebille, A. Al-Azri, E. Bateman, M. E. Correa, J. Raber-Durlacher, A. Kandwal, B. Mayo, R. G. Nair, A. Stringer, K. ten Bohmer, D. Thorpe, R. V. Lalla, S. Sonis, K. Cheng, S. Elad . On behalf of The Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO

Identification of candidate pelagic marine protected areas through a seabird seasonal-, multispecific- and extinction risk-based approach

With increasing pressure on the oceans from environmental change, there has been a global call for improved protection of marine ecosystems through the implementation of marine protected areas (MPAs). Here, we used species distribution modelling (SDM) of tracking data from 14 seabird species to identify key marine areas in the southwest Atlantic Ocean, valuing areas based on seabird species occurrence, seasonality and extinction risk. We also compared overlaps between the outputs generated by the SDM and layers representing important human threats (fishing intensity, ship density, plastic and oil pollution, ocean acidification), and calculated loss in conservation value using fishing and ship density as cost layers. The key marine areas were located on the southern Patagonian Shelf, overlapping extensively with areas of high fishing activity, and did not change seasonally, while seasonal areas were located off south and southeast Brazil and overlapped with areas of high plastic pollution and ocean acidification. Non-seasonal key areas were located off northeast Brazil on an area of high biodiversity, and with relatively low human impacts. We found support for the use of seasonal areas depending on the seabird assemblage used, because there was a loss in conservation value for the seasonal compared to the non-seasonal approach when using ‘cost’ layers. Our approach, accounting for seasonal changes in seabird assemblages and their risk of extinction, identified additional candidate areas for incorporation in the network of pelagic MPAs

Microplastic-Associated Biofilms: A Comparison of Freshwater and Marine Environments

Microplastics (<5 mm particles) occur within both engineered and natural freshwater ecosystems, including wastewater treatment plants, lakes, rivers, and estuaries. While a significant proportion of microplastic pollution is likely sequestered within freshwater environments, these habitats also constitute an important conduit of microscopic polymer particles to oceans worldwide. The quantity of aquatic microplastic waste is predicted to dramatically increase over the next decade, but the fate and biological implications of this pollution are still poorly understood. A growing body of research has aimed to characterize the formation, composition, and spatiotemporal distribution of microplastic-associated (“plastisphere”) microbial biofilms. Plastisphere microorganisms have been suggested to play significant roles in pathogen transfer, modulation of particle buoyancy, and biodegradation of plastic polymers and co-contaminants, yet investigation of these topics within freshwater environments is at a very early stage. Here, what is known about marine plastisphere assemblages is systematically compared with up-to-date findings from freshwater habitats. Through analysis of key differences and likely commonalities between environments, we discuss how an integrated view of these fields of research will enhance our knowledge of the complex behavior and ecological impacts of microplastic pollutants