Surgery (RMH) - Research Publications
Now showing items 1-12 of 155
Local delivery of corticosteroids in clinical ophthalmology: A review
Locally administered steroids have a long history in ophthalmology for the treatment of inflammatory conditions. Anterior segment conditions tend to be treated with topical steroids whilst posterior segment conditions generally require periocular, intravitreal or systemic administration for penetration. Over recent decades, the clinical applications of periocular steroid delivery have expanded to a wide range of conditions including macular oedema from retino-vascular conditions. Formulations have been developed with the aim to provide practical, targeted, longer-term and more efficacious therapy whilst minimizing side effects. Herein, we provide a comprehensive overview of the types of periocular steroid delivery, their clinical applications in ophthalmology and their side effects.
Overexpression of MMP13 is associated with clinical outcomes and poor prognosis in oral squamous cell carcinoma.
(Hindawi Limited, 2014)
Matrix metalloproteinase 13 (MMP13) plays a central role in the MMP activation cascade that enables degradation of the extracellular matrix and basement membranes, and it is identified as a potential driver in oral carcinogenesis. Therefore, this study aims to determine the copy number, mRNA, and protein expression of MMP13 in oral squamous cell carcinoma (OSCC) and to associate these expressions with clinicopathological parameters. Copy number, mRNA, and protein expression analysis of MMP13 were determined using real-time quantitative PCR and immunohistochemistry methods in OSCC samples. The correlations between MMP13 expressions and clinicopathological parameters were evaluated, and the significance of MMP13 as a prognostic factor was determined. Despite discrepancies between gene amplification and mRNA and protein overexpression rates, OSCC cases showed high amplification of MMP13 and overexpression of MMP13 at both mRNA and protein levels. High level of MMP13 protein expression showed a significant correlation with lymph node metastasis (P = 0.011) and tumor staging (P = 0.002). Multivariate Cox regression model analysis revealed that high level of mRNA and protein expression of MMP13 were significantly associated with poor prognosis (P < 0.050). Taken together, these observations indicate that the MMP13 protein overexpression could be considered as a prognostic marker of OSCC.
Phenotypic screen for oxygen consumption rate identifies an anti-cancer naphthoquinone that induces mitochondrial oxidative stress
A hallmark of cancer cells is their ability to reprogram nutrient metabolism. Thus, disruption to this phenotype is a potential avenue for anti-cancer therapy. Herein we used a phenotypic chemical library screening approach to identify molecules that disrupted nutrient metabolism (by increasing cellular oxygen consumption rate) and were toxic to cancer cells. From this screen we discovered a 1,4-Naphthoquinone (referred to as BH10) that is toxic to a broad range of cancer cell types. BH10 has improved cancer-selective toxicity compared to doxorubicin, 17-AAG, vitamin K3, and other known anti-cancer quinones. BH10 increases glucose oxidation via both mitochondrial and pentose phosphate pathways, decreases glycolysis, lowers GSH:GSSG and NAPDH/NAPD+ ratios exclusively in cancer cells, and induces necrosis. BH10 targets mitochondrial redox defence as evidenced by increased mitochondrial peroxiredoxin 3 oxidation and decreased mitochondrial aconitase activity, without changes in markers of cytosolic or nuclear damage. Over-expression of mitochondria-targeted catalase protects cells from BH10-mediated toxicity, while the thioredoxin reductase inhibitor auranofin synergistically enhances BH10-induced peroxiredoxin 3 oxidation and cytotoxicity. Overall, BH10 represents a 1,4-Naphthoquinone with an improved cancer-selective cytotoxicity profile via its mitochondrial specificity.
Genotype-free demultiplexing of pooled single-cell RNA-seq
A variety of methods have been developed to demultiplex pooled samples in a single cell RNA sequencing (scRNA-seq) experiment which either require hashtag barcodes or sample genotypes prior to pooling. We introduce scSplit which utilizes genetic differences inferred from scRNA-seq data alone to demultiplex pooled samples. scSplit also enables mapping clusters to original samples. Using simulated, merged, and pooled multi-individual datasets, we show that scSplit prediction is highly concordant with demuxlet predictions and is highly consistent with the known truth in cell-hashing dataset. scSplit is ideally suited to samples without external genotype information and is available at: https://github.com/jon-xu/scSplit.
Therapeutic Targeting of Cancer Stem Cells in Human Glioblastoma by Manipulating the Renin-Angiotensin System
Patients with glioblastoma (GB), a highly aggressive brain tumor, have a median survival of 14.6 months following neurosurgical resection and adjuvant chemoradiotherapy. Quiescent GB cancer stem cells (CSCs) invariably cause local recurrence. These GB CSCs can be identified by embryonic stem cell markers, express components of the renin-angiotensin system (RAS) and are associated with circulating CSCs. Despite the presence of circulating CSCs, GB patients rarely develop distant metastasis outside the central nervous system. This paper reviews the current literature on GB growth inhibition in relation to CSCs, circulating CSCs, the RAS and the novel therapeutic approach by repurposing drugs that target the RAS to improve overall symptom-free survival and maintain quality of life.
Plant poisoning leads to alpha-synucleinopathy and neuromelanopathy in kangaroos
(NATURE PUBLISHING GROUP, 2019-11-13)
The pathogenesis of synucleinopathies, common neuropathological lesions normally associated with some human neurodegenerative disorders such as Parkinson's disease, dementia with Lewy bodies and multiple system atrophy, remains poorly understood. In animals, ingestion of the tryptamine-alkaloid-rich phalaris pastures plants causes a disorder called Phalaris staggers, a neurological syndrome reported in kangaroos. The aim of the study was to characterise the clinical and neuropathological changes associated with spontaneous cases of Phalaris staggers in kangaroos. Gross, histological, ultrastructural and Immunohistochemical studies were performed to demonstrate neuronal accumulation of neuromelanin and aggregated α-synuclein. ELISA and mass spectrometry were used to detect serum-borne α-synuclein and tryptamine alkaloids respectively. We report that neurons in the central and enteric nervous systems of affected kangaroos display extensive accumulation of neuromelanin in the perikaryon without affecting neuronal morphology. Ultrastructural studies confirmed the typical structure of neuromelanin. While we demonstrated strong staining of α-synuclein, restricted to neurons, intracytoplasmic Lewy bodies inclusions were not observed. α-synuclein aggregates levels were shown to be lower in sera of the affected kangaroos compared to unaffected herd mate kangaroos. Finally, mass spectrometry failed to detect the alkaloid toxins in the sera derived from the affected kangaroos. Our preliminary findings warrant further investigation of Phalaris staggers in kangaroos, potentially a valuable large animal model for environmentally-acquired toxic synucleinopathy.
The projected burden of primary total knee and hip replacement for osteoarthritis in Australia to the year 2030
BACKGROUND: Comprehensive national joint replacement registries with well-validated data offer unique opportunities for examining the potential future burden of hip and knee osteoarthritis (OA) at a population level. This study aimed to forecast the burden of primary total knee (TKR) and hip replacements (THR) performed for OA in Australia to the year 2030, and to model the impact of contrasting obesity scenarios on TKR burden. METHODS: De-identified TKR and THR data for 2003-2013 were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. Population projections and obesity trends were obtained from the Australian Bureau of Statistics, with public and private hospital costs sourced from the National Hospital Cost Data Collection. Procedure rates were projected according to two scenarios: (1) constant rate of surgery from 2013 onwards; and (2) continued growth in surgery rates based on 2003-2013 growth. Sensitivity analyses were used to estimate future TKR burden if: (1) obesity rates continued to increase linearly; or (2) 1-5% of the overweight or obese population attained a normal body mass index. RESULTS: Based on recent growth, the incidence of TKR and THR for OA is estimated to rise by 276% and 208%, respectively, by 2030. The total cost to the healthcare system would be $AUD5.32 billion, of which $AUD3.54 billion relates to the private sector. Projected growth in obesity rates would result in 24,707 additional TKRs totalling $AUD521 million. A population-level reduction in obesity could result in up to 8062 fewer procedures and cost savings of up to $AUD170 million. CONCLUSIONS: If surgery trends for OA continue, Australia faces an unsustainable joint replacement burden by 2030, with significant healthcare budget and health workforce implications. Strategies to reduce national obesity could produce important TKR savings.
Mitochondrial Fusion by M1 Promotes Embryoid Body Cardiac Differentiation of Human Pluripotent Stem Cells
(HINDAWI LTD, 2019-09-19)
Human induced pluripotent stem cells (iPSCs) can be differentiated in vitro into bona fide cardiomyocytes for disease modelling and personalized medicine. Mitochondrial morphology and metabolism change dramatically as iPSCs differentiate into mesodermal cardiac lineages. Inhibiting mitochondrial fission has been shown to promote cardiac differentiation of iPSCs. However, the effect of hydrazone M1, a small molecule that promotes mitochondrial fusion, on cardiac mesodermal commitment of human iPSCs is unknown. Here, we demonstrate that treatment with M1 promoted mitochondrial fusion in human iPSCs. Treatment of iPSCs with M1 during embryoid body formation significantly increased the percentage of beating embryoid bodies and expression of cardiac-specific genes. The pro-fusion and pro-cardiogenic effects of M1 were not associated with changes in expression of the α and β subunits of adenosine triphosphate (ATP) synthase. Our findings demonstrate for the first time that hydrazone M1 is capable of promoting cardiac differentiation of human iPSCs, highlighting the important role of mitochondrial dynamics in cardiac mesoderm lineage specification and cardiac development. M1 and other mitochondrial fusion promoters emerge as promising molecular targets to generate lineages of the heart from human iPSCs for patient-specific regenerative medicine.
Understanding the role of primary tumour localisation in colorectal cancer treatment and outcomes
(ELSEVIER SCI LTD, 2017-10-01)
Metastatic colorectal carcinoma (mCRC) is a heterogeneous disease with differing outcomes and clinical responses and poor prognosis. CRCs can be characterised by their primary tumour location within the colon. The left-sided colon, derived from the hindgut, includes the distal third of the transverse colon, splenic flexure, descending colon, sigmoid colon and rectum. The right-sided colon, derived from the midgut, includes the proximal two-thirds of the transverse colon, ascending colon and caecum. Sometimes, the rectum is described separately, despite originating from the hindgut, and in many clinical series, the left-sided colon includes only tumours within and distal to the splenic flexure. Differences in the microbiome, clinical characteristics and chromosomal and molecular characteristics have been reported between the right and left side of the colon, regardless of how this is defined. There is now strong evidence from clinical studies in patients with mCRC for the prognostic effect of primary tumour location. The impact of primary colonic tumour location on response to treatment is now under investigation in a large number of clinical studies in patients with mCRC. In this review, we summarise the microbiome, clinical, chromosomal and molecular differences associated with the primary location of CRC. We present an overview of the proven prognostic impact of primary tumour location for patients with mCRC and discuss emerging data for the predictive impact of primary tumour location on clinical outcome.
IL33 and Mast Cells-The Key Regulators of Immune Responses in Gastrointestinal Cancers?
(Frontiers Media SA, 2020)
The Interleukin (IL-)1 family IL33 is best known for eliciting type 2 immune responses by stimulating mast cells (MCs), regulatory T-cells (Tregs), innate lymphoid cells (ILCs) and other immune cells. MCs and IL33 provide critical control of immunological and epithelial homeostasis in the gastrointestinal (GI) tract. Meanwhile, the role of MCs in solid malignancies appears tissue-specific with both pro and anti-tumorigenic activities. Likewise, IL33 signaling significantly shapes immune responses in the tumor microenvironment, but these effects remain often dichotomous when assessed in experimental models of cancer. Thus, the balance between tumor suppressing and tumor promoting activities of IL33 are highly context dependent, and most likely dictated by the mixture of cell types responding to IL33. Adding to this complexity is the promiscuous nature by which MCs respond to cytokines other than IL33 and release chemotactic factors that recruit immune cells into the tumor microenvironment. In this review, we integrate the outcomes of recent studies on the role of MCs and IL33 in cancer with our own observations in the GI tract. We propose a working model where the most abundant IL33 responsive immune cell type is likely to dictate an overall tumor-supporting or tumor suppressing outcome in vivo. We discuss how these opposing responses affect the therapeutic potential of targeting MC and IL33, and highlight the caveats and challenges facing our ability to effectively harness MCs and IL33 biology for anti-cancer immunotherapy.
CD8(+) tumor-infiltrating lymphocytes within the primary tumor of patients with synchronous de novo metastatic colorectal carcinoma do not track with survival
Objectives: Tumor-infiltrating lymphocytes (TIL), particularly CD8+ TILs in patients with colorectal cancer (CRC), are highly prognostic in the early-disease stages (I-II). In metastatic disease (stage IV; mCRC), their influence is less well defined. It has presumably failed to contain tumor cells to the primary site; however, is this evident? We explored the prognostic impact of TILs at the primary site in patients who presented de novo with mCRC. Methods: Treatment-naïve patients (109) with mCRC were assessed for CD8+ TILs and PD-L1 expression. Microsatellite instability (MSI) was evaluated by IHC for PMS2 and MSH6 proteins and/or by PCR using the Bethesda panel. Results: Microsatellite instability-high tumors had significantly more CD8+ TILs, with no significant survival advantage observed between MSI-H and microsatellite stable (MSS) tumors (12 vs 19 months, P = 0.304). TIL density for all cases had no impact on OS (low: 20 vs high: 13 months, P = 0.426), while PD-L1 of 1% or higher was associated with reduced mean survival (9.6 vs 18.9 months; P = 0.038). MSI-H tumors and associated immune cells had higher PD-L1 expression than in MSS cases. A positive correlation between PD-L1 on immune cells and CD8+ve TILs was found. A subset of MSS tumors had relatively high TILs approximating that of MSI-H tumors. Conclusion: In contrast to early-stage CRC, the immune response in primary tumors of patients with de novo mCRC does not appear to influence survival. A subgroup of MSS tumors was identified with increased TILs/PD-L1 comparable to MSI-H tumors, traditionally not be considered for immune checkpoint blockade and perhaps should be.
Prostatic relapse of an undifferentiated teratoma 24 years after orchidectomy.
(Springer Science and Business Media LLC, 2015-10-01)
BACKGROUND: Non-seminomatous germ cell tumours make up about 40 % of all germ cell tumours, which in turn are the most common tumours in men aged 15-44 years. Low risk stage I non-seminomatous germ cell tumours, which are confined to the testes, are commonly treated by orchiectomy and surveillance. Up to 20 % of patients with this diagnosis relapse, usually within 1-2 years of follow up, but very rarely after more than 5 years. The most common sites of relapse are the retroperitoneal lymph nodes, the mediastinum, and the lungs. We describe a case of relapse in the prostate over 20 years after initial diagnosis, which has not been described in the literature so far. CASE PRESENTATION: This report presents a 49-year-old white British man with relapsed testicular non-seminomatous germ cell tumour 22 years after initial treatment with orchidectomy only. He relapsed with a prostatic mass, haematospermia and back pain. His prostate specific antigen levels were within normal range. Alpha feto-protein and lactate dehydrogenase levels were elevated, and his human chorionic gonadotrophin levels were normal. A biopsy confirmed undifferentiated malignant tumour, shown immunohistochemically to be a yolk sac tumour. The patient was initially treated with bleomycin, etoposide and cisplatin chemotherapy, but developed bleomycin-related pulmonary side effects after two cycles. His treatment was changed and he completed four cycles of chemotherapy by receiving two cycles of etoposide, ifosfamide, and cisplatin. Post treatment blood tumour markers were normal, but a follow up computed tomography showed a mass in the base of the prostate, the trigone and the left distal ureter which was surgically resected. The histology from the surgical resection was of necrotic tissue. The patient is now in follow up at 3 years after treatment with no evidence of residual disease on computed tomography. His Alpha feto-protein, beta human chorionic gonadotrophin and lactate dehydrogenase levels are normal. CONCLUSIONS: Very late relapse in stage I non-seminomatous germ cell tumours is extremely rare and the prostate is a highly unusual site of relapsed disease. For diagnosis of late relapse, this case confirms the value of serum biomarkers in germ cell tumours, in particular non-seminomatous germ cell tumours.