Bariatric surgery and the neurohormonal switch: Early insulin resistance recordings after laparoscopic sleeve gastrectomy.

Laparoscopic sleeve gastrectomy (LSG) is a bariatric operation with a safe risk profile. It has been proven to successfully reduce weight, decrease insulin resistance (IR), and ameliorate diabetes mellitus. The aim of this study was to determine if there is an early improvement in IR after LSG and its association with weight loss. This was a prospective observational study of 32 patients who underwent LSG at a single center over a 3-year period. Serum insulin and fasting glucose levels were recorded preoperatively, on day 1 postoperatively, and 3 weeks after LSG. IR levels were calculated using the Homeostasis Model Assessment 2 Version 2.23. IR levels were compared along with the overall weight loss, via body mass index. ß-cell function was the secondary outcome. IR significantly improved the day after surgery with a statistically significant mean difference of 0.89 units (P = .043) and significantly more so 3 weeks postoperatively, with a mean difference of 4.32 units (P < .0005). ß-cell function reduced 3 weeks postoperatively, with a mean difference of 23.95 %ß (P = .025), while body mass index significantly reduced, with a mean difference of 4.32 kg/m2 (P < .0005). Early improvement of IR was observed on postoperative day 1 after LSG before any weight loss. This raises the possibility of an undetermined, underlying neurohormonal switch that improves IR. Further investigation is needed to determine this mechanism, as it may lead to an improvement in the medical management of diabetes mellitus.

Proteomic analysis of low- and high-grade human colon adenocarcinoma tissues and tissue-derived primary cell lines reveals unique biological functions of tumours and new protein biomarker candidates.

BACKGROUND: Colon cancer is the third most common cancer and second highest cause of cancer deaths worldwide. The aim of the study was to find new biomarkers for diagnosis, prognosis and therapeutic drug targets for this disease. METHODS: Four low-grade and four high-grade human colon adenocarcinoma tumours with patient-matched normal colon tissues were analysed. Additionally, tissue-derived primary cell lines were established from each tumour tissue. The cell lines were validated using DNA sequencing to confirm that they are a suitable in vitro model for colon adenocarcinoma based on conserved gene mutations. Label-free quantitation proteomics was performed to compare the proteomes of colon adenocarcinoma samples to normal colon samples, and of colon adenocarcinoma tissues to tissue-derived cell lines to find significantly differentially abundant proteins. The functions enriched within the differentially expressed proteins were assessed using STRING. Proteomics data was validated by Western blotting. RESULTS: A total of 4767 proteins were identified across all tissues, and 4711 across primary tissue-derived cell lines. Of these, 3302 proteins were detected in both the tissues and the cell lines. On average, primary cell lines shared about 70% of proteins with their parent tissue, and they retained mutations to key colon adenocarcinoma-related genes and did not diverge far genetically from their parent tissues. Colon adenocarcinoma tissues displayed upregulation of RNA processing, steroid biosynthesis and detoxification, and downregulation of cytoskeletal organisation and loss of normal muscle function. Tissue-derived cell lines exhibited increased interferon-gamma signalling and aberrant ferroptosis. Overall, 318 proteins were significantly up-regulated and 362 proteins significantly down-regulated by comparisons of high-grade with low-grade tumours and low-grade tumour with normal colon tissues from both sample types. CONCLUSIONS: The differences exhibited between tissues and cell lines highlight the additional information that can be obtained from patient-derived primary cell lines. DNA sequencing and proteomics confirmed that these cell lines can be considered suitable in vitro models of the parent tumours. Various potential biomarkers for colon adenocarcinoma initiation and progression and drug targets were identified and discussed, including seven novel markers: ACSL4, ANK2, AMER3, EXOSC1, EXOSC6, GCLM, and TFRC.

Colon adenocarcinoma-derived cells possessing stem cell function can be modulated using renin-angiotensin system inhibitors.

The cancer stem cell (CSC) concept proposes that cancer recurrence and metastasis are driven by CSCs. In this study, we investigated whether cells from colon adenocarcinoma (CA) with a CSC-like phenotype express renin-angiotensin system (RAS) components, and the effect of RAS inhibitors on CA-derived primary cell lines. Expression of RAS components was interrogated using immunohistochemical and immunofluorescence staining in 6 low-grade CA (LGCA) and 6 high-grade CA (HGCA) tissue samples and patient-matched normal colon samples. Primary cell lines derived from 4 HGCA tissues were treated with RAS inhibitors to investigate their effect on cellular metabolism, tumorsphere formation and transcription of pluripotency genes. Immunohistochemical and immunofluorescence staining showed expression of AT2R, ACE2, PRR, and cathepsins B and D by cells expressing pluripotency markers. ß-blockers and AT2R antagonists reduced cellular metabolism, pluripotency marker expression, and tumorsphere-forming capacity of CA-derived primary cell lines. This study suggests that the RAS is active in CSC-like cells in CA, and further investigation is warranted to determine whether RAS inhibition is a viable method of targeting CSCs.

Colon adenocarcinoma-derived cells that express induced-pluripotent stem cell markers possess stem cell function.

AIMS: Much work has been done to find markers of cancer stem cells (CSCs) that distinguish them from the tumor bulk cells and normal cells. Recent CSC research has applied the induced pluripotent stem cell (iPSC) concept. In this study, we investigated the expression of a panel of iPSC markers in primary colon adenocarcinoma (CA)-derived cell lines. MATERIALS AND METHODS: Expression of iPSC markers by CA-derived primary cell lines was interrogated using immunocytochemistry, western blotting and RT-qPCR. The stem cell function of these cells was then assessed in vitro using differentiation and tumorsphere assays. RESULTS: Expression of iPSC markers OCT4, SOX2, NANOG, KLF4 and c-MYC was more widespread in high-grade CA (HGCA) cell lines than low-grade CA (LGCA) cell lines, as demonstrated by western blotting and RT-qPCR. These cells could be induced to differentiate down the three embryonic lineages. Cells derived from HGCA were more capable of forming tumorspheres than those derived from LGCA. EpCAM sorting revealed that a population enriched for EpCAMHigh cells formed larger tumorspheres than EpCAMLow cells. Pluripotency markers, SSEA4 and TRA-1-60, were co-expressed by a small subpopulation of cells that also co-expressed SOX2 in 75% and OCT4 in 50% of the cell lines. CONCLUSIONS: CA-derived primary cell lines contain tumorsphere-forming cells which express key pluripotency genes and can differentiate down 3 embryonic lineages, suggesting a pluripotent CSC-like phenotype. There appear to be two iPSC-like subpopulations, one with high EpCAM expression which forms larger tumorspheres than another with low EpCAM expression. Furthermore, these cells can be characterized based on iPSC marker expression, as we have previously demonstrated in the original CA tumor tissues.

Cancer stem cell subpopulations in primary colon adenocarcinoma.

AIMS: The cancer stem cell concept proposes that tumor growth and recurrence is driven by a small population of cancer stem cells (CSCs). In this study we investigated the expression of induced-pluripotent stem cell (iPSC) markers and their localization in primary low-grade adenocarcinoma (LGCA) and high-grade adenocarcinoma (HGCA) and their patient-matched normal colon samples. MATERIALS AND METHODS: Transcription and translation of iPSC markers OCT4, SOX2, NANOG, KLF4 and c-MYC were investigated using immunohistochemical (IHC) staining, RT-qPCR and in-situ hybridization (ISH). RESULTS: All five iPSC markers were detected at the transcriptional and translational levels. Protein abundance was found to be correlated with tumor grade. Based on their protein expression within the tumors, two sub-populations of cells were identified: a NANOG+/OCT4- epithelial subpopulation and an OCT4+/NANOG- stromal subpopulation. All cases were accurately graded based on four pieces of iPSC marker-related data. CONCLUSIONS: This study suggests the presence of two putative sub-populations of CSCs: a NANOG+/OCT4- epithelial subpopulation and an OCT4+/NANOG- stromal subpopulation. Normal colon, LGCA and HGCA could be accurately distinguished from one another using iPSC marker expression. Once validated, novel combinations of iPSC markers may provide diagnostic and prognostic value to help guide patient management.

Therapeutic Targeting of Cancer Stem Cells via Modulation of the Renin-Angiotensin System.

Cancer stem cells (CSCs) are proposed to be the cells that initiate tumorigenesis and maintain tumor development due to their self-renewal and multipotency properties. CSCs have been identified in many cancer types and are thought to be responsible for treatment resistance, metastasis, and recurrence. As such, targeting CSCs specifically should result in durable cancer treatment. One potential option for targeting CSCs is by manipulation of the renin-angiotensin system (RAS) and pathways that converge on the RAS with numerous inexpensive medications currently in common clinical use. In addition to its crucial role in cardiovascular and body fluid homeostasis, the RAS is vital for stem cell maintenance and differentiation and plays a role in tumorigenesis and cancer prevention, suggesting that these roles may converge and result in modulation of CSC function by the RAS. In support of this, components of the RAS have been shown to be expressed in many cancer types and have been more recently localized to the CSCs in some tumors. Given these roles of the RAS in tumor development, clinical trials using RAS inhibitors either singly or in combination with other therapies are underway in different cancer types. This review outlines the roles of the RAS, with respect to CSCs, and suggests that the presence of components of the RAS in CSCs could offer an avenue for therapeutic targeting using RAS modulators. Due to the nature of the RAS and its crosstalk with numerous other signaling pathways, a systems approach using traditional RAS inhibitors in combination with inhibitors of bypass loops of the RAS and other signaling pathways that converge on the RAS may offer a novel therapeutic approach to cancer treatment.

Expression and Localization of Cathepsins B, D and G in Cancer Stem Cells in Liver Metastasis From Colon Adenocarcinoma.

AIM: We have previously identified and characterized cancer stem cell (CSC) subpopulations in liver metastasis from colon adenocarcinoma (LMCA). In this study we investigated the expression and localization of cathepsins B, D and G, in relation to these CSCs. METHODS: 3,3-Diaminobenzidine (DAB) immunohistochemical (IHC) staining for cathepsins B, D and G was performed on 4µm-thick formalin-fixed paraffin-embedded LMCA sections from nine patients. Immunofluorescence (IF) IHC staining was performed on three representative samples of LMCA from the original cohort of nine patients, to determine the localization of these cathepsins in relation to the CSC subpopulations. NanoString mRNA analysis and Western Blotting (WB) were used to examine the transcript and protein expression of these cathepsins, respectively. Enzyme activity assays were utilized to determine their functional activity. Data acquired from counting of cells staining positively of the cathepsins on the DAB IHC-stained slides and from Nanostring mRNA analysis were subjected to statistical analyses to determine significance. RESULTS: DAB IHC staining demonstrated expression of cathepsins B, D and G within LMCA. IF IHC staining demonstrated the expression of both cathepsin B and cathepsin D by the OCT4- cells within the tumor nests and the OCT4+ CSC subpopulation within the peritumoral stroma. NanoString mRNA analysis showed significantly greater transcript expression of cathepsin B and cathepsin D, compared to cathepsin G. WB confirmed expression of cathepsin B and cathepsin D proteins, while cathepsin G was below detectable levels. Enzyme activity assays showed functional activity of cathepsin B and cathepsin D. CONCLUSION: Our study demonstrated novel finding of the expression of cathepsin B, cathepsin D, and possibly cathepsin G by the putative CSC subpopulations within LMCA.

Cancer stem cells in colorectal cancer: a review.

Colorectal cancer (CRC) is the second most common cancer in women and the third most common in men. Adenocarcinoma accounts for 90% of CRC cases. There has been accumulating evidence in support of the cancer stem cell (CSC) concept of cancer which proposes that CSCs are central in the initiation of cancer. CSCs have been the focus of study in a range of cancers, including CRC. This has led to the identification and understanding of genes involved in the induction and maintenance of pluripotency of stem cells, and markers for CSCs, including those investigated specifically in CRC. Knowledge of the expression pattern of CSCs in CRC has been increasing in recent years, revealing a heterogeneous population of cells within CRC ranging from pluripotent to differentiated cells, with overlapping and sometimes unique combinations of markers. This review summarises current literature on the understanding of CSCs in CRC, including evidence of the presence of CSC subpopulations, and the stem cell markers currently used to identify and localise these CSC subpopulations. Future research into this field may lead to improved methods for early detection of CRC, novel therapy and monitoring of treatment for CRC and other cancer types.

Characterization of Cancer Stem Cells in Colon Adenocarcinoma Metastasis to the Liver.

BACKGROUND: Fifty percent of colorectal cancer (CRC) patients develop liver metastasis. This study identified and characterized cancer stem cells (CSCs) within colon adenocarcinoma metastasis to the liver (CAML). METHODS: 3,3-Diaminobenzidine immunohistochemical (IHC) staining was performed on nine CAML samples for embryonic stem cell (ESC) markers OCT4, SOX2, NANOG, c-Myc, and KLF4. Immunofluorescence (IF) IHC staining was performed to investigate coexpression of two markers. NanoString mRNA expression analysis and colorimetric in situ hybridization (CISH) were performed on four snap-frozen CAML tissue samples for transcript expression of these ESC markers. Cells stained positively and negatively for each marker by IHC and CISH staining were counted and analyzed. RESULTS: 3,3-Diaminobenzidine IHC staining, and NanoString and CISH mRNA analyses demonstrated the expression of OCT4, SOX2, NANOG, c-Myc, and KLF4 within in all nine CAML samples, except for SOX2 which was below detectable levels on NanoString mRNA analysis. IF IHC staining showed the presence of a SOX2+/NANOG+/KLF4+/c-Myc+/OCT- CSC subpopulation within the tumor nests, and a SOX2+/NANOG+/KLF4+/c-Myc+/OCT4- CSC subpopulation and a SOX2+/NANOG+/KLF4+/c-Myc+/OCT4+ CSC subpopulation within the peritumoral stroma. CONCLUSION: The novel finding of three CSC subpopulations within CAML provides insights into the biology of CRC.

A morbidity/mortality analysis of a tertiary level upper gastrointestinal/hepatopancreaticobiliary surgical unit.

Internationally, regionalisation of major upper gastrointestinal/hepatopancreaticobiliary (UGI/HPB) surgery to a selected number of expert hospital centres has demonstrated that high hospital volume is associated with lower mortality and morbidity. The Wellington UGI/HPB unit compared to international institutions is a low volume unit, however within New Zealand we perform a high number of Upper GI/HPB cases. AIMS: The aim of this study was to evaluate the quality measures of morbidity and mortality of major upper gastrointestinal and hepatopancreatobiliary surgeries performed at the Wellington UGI/HPB unit. METHODS: An analysis was conducted to evaluate the major UGI/HBP surgeries performed at Wellington over a six-year period. Patient demographics, and morbidity and mortality were stratified using the Clavien-Dindo classification of surgical complications. RESULTS: Three hundred and twenty-nine major elective cases were performed at the Wellington UGI/HPB unit over the six-year period. Sixty-five percent of patients experienced no morbidity, 19% of patients experienced mild morbidity, which had little effect on recovery, 14% of patients experienced major morbidity and 0.6% (two cases) progressed to mortality. When major UGI/HPB resections were specifically analysed, there were a total of 184 patients with 42 major morbidity (22.8%) and two mortalities (1.1%). CONCLUSION: Compared with international standards, the Wellington UGI/HPB unit is a low volume centre but has delivered an acceptable quality of care with a low major morbidity and mortality for this type of surgery.

A Low Impact Approach to Infected Pancreatic Necrosis: Review of a Case Series.

BACKGROUND: Infected pancreatic necrosis develops in approximately one third of patients with necrotizing pancreatitis and can lead to significant morbidity and mortality rates. Historically, open necrosectomy has been the mainstay of management for these patients but is in itself a morbid procedure. In recent times, minimally invasive techniques have evolved to allow a less invasive approach to these patients. Percutaneous catheter drainage of infected pancreatic necrosis is a technique that has been demonstrated to be potentially useful in the treatment of this group of patients. PATIENTS AND METHODS: The aim of this study was to review outcomes and define the technique of percutaneous catheter drainage in patients with infected pancreatic necrosis. All patients with infected pancreatic necrosis were exclusively treated with percutaneous drainage over the study period. Acute Physiology and Chronic Health Evaluation (APACHE) II score, number and size of drains, drainage technique and drain management, hospital and intensive care unit (ICU) stay, nutritional requirements, and morbidity and mortality data were evaluated for the patient group. Computed tomography (CT) scans were used to assess the progression of the disease process and the effectiveness of the treatment. RESULTS: There were nine patients with infected pancreatic necrosis in this case series between 2007 and 2012, all of whom were treated with percutaneous catheter drainage alone. The median APACHE II score in the patient group was 11, with a median stay in the ICU of 3 d and median hospital stay of 41 d. On average, nine CT scans were performed per patient during the hospital admission. A median of three drains were inserted per patient, and in the course of the study, it was evident that the larger drain size was the most effective. In eight of the nine patients in the group, complications developed that were both directly and indirectly related to the pancreatitis, but were effectively managed. There were no deaths. CONCLUSION: Percutaneous catheter drainage as a stand-alone intervention is an alternative strategy for infected pancreatic necrosis and can be used with acceptable morbidity and mortality rates in this challenging group of patients.

Experience of imaging following laparoscopic sleeve gastrectomy.

BACKGROUND: We aimed to report our experience with upper gastrointestinal (UGI) contrast studies and computed tomography (CT) swallow studies after laparoscopic sleeve gastrectomy, and comment on the merits of each modality. METHOD: Retrospective review of all patients undergoing laparoscopic sleeve gastrectomy (LSG) in a New Zealand hospital between 2011 and 2014 was conducted. Over this time period, routine UGI was replaced by CT swallow studies. All medical records and radiology were reviewed and pertinent findings reported. RESULTS: Seventy-nine patients underwent LSG over this time period and one patient had to be excluded; 48 (61.5%) had a UGI study and 30 patients (38.5%) had CT swallow. There were no leaks in this study and no leaks became clinically significant. Sixteen of 30 patients (53.3%) undergoing CT swallow had significant incidental findings demonstrated on axial imaging that required follow-up. CONCLUSION: CT swallow can provide the same information as a UGI but has a significant rate of incidental findings. The rate of incidental pathology on CT is higher than that quoted in the general population. In a bariatric population, this may allow early detection and treatment of co-existent pathology.

Primary lymph node gastrinoma: 2 cases and a review of the literature.

INTRODUCTION: Gastrinoma is a rare tumour of the diffuse neuroendocrine system with the primary invariability located within the duodenum or pancreas. Numerous authors have described gastrinoma apparently isolated to peripancreatic lymph nodes, following exhaustive radiological and operative localisation and examination. METHOD: Two cases of apparent primary lymph node gastrinoma seen in our institution are presented, along with a literature review including 58 other presented cases. RESULTS: On prolonged follow-up up to 131 months, 34 patients have remained in remission supporting the diagnosis of primary lymph node gastrinoma. Occult primary disease, usually in the form of microduodenal tumours, have become evident in the remaining 24 cases. CONCLUSION: The existence of primary lymph node gastrinoma is supported by many presented case studies, but long-term follow-up of all patients should occur in the expectation that occult primary disease will become apparent in some.