Hepatocyte cell constructs for bioartificial liver applications

Question for literature review: “Hepatocyte cell constructs for bioartificial liver applications”
The following text was given to me by the lecturer who will mark the literature review, briefly discussing the experimentation that will happen for my project plan and what to include in the literature review in the conclusion, as my hypothesis will be made from a research plan depending on this information:
Liver transplant remains the only successful replacement strategy for the failing liver, but many patients die whilst waiting for a donor organ. Experimental strategies include the development of a bioreactor in which hepatocytes are loaded within a matrix and used as part of a dialysis system to bridge patients to recovery or transplant. Within this project you will synthesise macroporous hydrogel biomaterials and investigate the impact of cell growth cues on cultured hepatocyte function for a prototype bioartificial liver application.
Senescence and the bioartificial liver
There currently no alternatives to transplant for patients whose liver fails due to disease or injury. The incidence of liver disease is rising in line with increases in alcohol abuse, obesity and hepatitis C infection. This means that alternatives to the reliance on transplants are necessary. There are acellular and cell-based approaches under development to bridge to transplant or recovery. These include acellular liver dialysis devices such as MARS and PROMETHEUS in addition to cellular, hepatocyte loaded bioartificial liver (BAL) approaches. BAL devices, incorporating a metabolic and detoxification function may be a better approach. However, despite many clinical studies, no clear link to device use and patient survival benefit has been shown. One reason may be the failure of these devices to maintain the metabolic active hepatocytes loaded into the device.
Our lab has been exploring the use of a bioengineering approach based on loading of a multi-layered, alginate and RGD peptide functionalised macroporous polymer with hepatocytes. This prototype (without the cells) has been testing for safety using a bile duct ligation model of liver inflammation and fibrosis in the PhD work of Flavia Bonalumi.
It is known that cell senescence, or the permanent cell cycle arrest of hepatocytes, occurs and contributes to declining liver function in liver disease. In the supervisors PhD we are investigating the hypothesis that senescence induced by BAL prototype exposure to liver toxins may promote altered hepatocyte function and ultimately loss of BAL activity in liver replacement.
Plan of Work
In your project you will be working to:
A. Investigate the impact of liver toxins on HepG2 hepatocyte growth and division using Ki67 and p53 immunocytochemical markers (Look up what Ki67 and p53 are!). This will involve cell culture, seeding of cells onto cover slips, exposure to toxins, fixing of cells, addition of antibodies to Ki67/ p53 followed by counting of positively stained cells by confocal microscopy. Note: EdU marker is a better but more expensive measure for senescence so we use Ki67 and p53 markers to infer changes in cell cycle and senscence
B. Investigate the protective effect of antioxidant chemicals on liver toxin induced cell senescence using the protocol in A but adding antioxidant chemical prior to liver toxin exposure
C. If we have time you will also be shown how to make the cryogel cell matrices, seed hepatocytes onto the matrices and then assess the affect of exposure to liver toxin cocktail on key measures of hepatocyte function such as albumin production and urea. These are done with an ELISA assay.
– There is a word limit of 4000 words for this literature review, and it is due on Monday 7th December at 12PM. Can a word count be included at the end of the work please, before the references list page.
– Can the references included be in Harvard style and minimum 35 please, the more the better, and for the writer to not only describe the papers but to also criticize it as well. Could the references papers be up to date please, not too old.
To make the views included in the literature review always based on the literature from the reference papers, as the science tells us the current truth – so no personal thoughts please, and to draw back to the key issues in the articles/research papers.
Not too many general sentences, can all sentences be backed with data and statistics from the references. Can concise scientific terminology be used, and the sentences clear and simple please however avoid generic sentences please, with use of figures and data.
Please make sure to not make it a listed summary of research in the field of liver disease/treatments, or a chronology of the development of research in the particular area instead a critical analysis of background research relevant topic in order to justify the hypothesis and approach to my research as the literature review will be a foundation for my research project which will be something including the text in the top in italics – as that is what I will be researching.
– Table of contents included please.
– Could the writer please try to make the format/contents of the literature review something along the lines of the subheading below (or whatever they think would be the best structure to get the highest marks please):
– Introduction; include context, justification for the literature review and my research (the information is the text in italics on page 1), why this and why now? Set the scene.
– Subsections, these could be overview of the topic, key issues/studies linked to my research focus and any directly relevant studies. Key element is to make sure to critique and not a description of the reference’s literature. Critical review of concepts relevant to my project. Please could the writer do the work in a way in which the first sentence of each sub heading paragraph tells the reader where the paragraph is going and the final sentence to be a linker to the next subsections paragraphs topic.
– Background information on liver disease/failure and the current treatments there are available. Don’t talk about liver disease as an umbrella, be specific as some are acute and chronic. Any issues within liver disease and the current treatments discuss. Acute and chronic diseases and what these are, e.g. chronic develops over years and deep episodes happen. In acute liver diseases discuss the injury and the treatment, can a bioartificial liver be used or is a transplant the final option? Explain that in the UK, there is no other alternative than transplantation, bioartificial liver is under trail and not yet out, compare this data from Europe. Cellular and non-cellular treatments, as well as other therapeutic strategies for treatment (Please back up each statement with data and references from scientific papers).
So discuss the background, current ongoing work, any gaps in this work/treatment, and unknown and contested issues.
– Discuss hepatocyte treatments, and how they are underdeveloped.
– Bioartificial liver; the number of cells needed to be successful is 9 billion. Discuss in this section issues with cell sources, stem cells, transdifferentiating, the material that is used in the making of bioartificial livers, cryo gels blood diffusion system. Then go onto the matrix of the cells. Any clinical trials, such as dialysis. What causes cells to not maintain liver function in the liver; could lose their phenotype or other factors include please. Talk about senescence, and what it is and how to stop it.
Include information on how as liver disease develops in an individual, hepatocytes start to fail.
– Cell types for use within bioartificial liver
– Cyro cells and their use within treatment
– Ki67 cells and DAPI cells and where they are present. (Ki67 are visible in 2D cells and not in 3D cyro cells, as they are difficult to look at under the microscope). Under a microscope if the Ki67 staining is on the nucleus, then you are able to see green Ki67 positive cells – the greener cells the more liver toxins are exposed. DAPI makes the cells stained blue once seen under microscopes.
– Talk about how Ki67 cells will be beneficial in bioartificial liver application and their success rate.
– Conclusion; summarise the ideas, draw together the knowns and unknowns to justify my project hypothesis. Identify the key gaps/issues that my project will address – therefore what will be the aim of my project? Identify my project hypothesis. Summarise my research plan, so a plan on how I will construct the cells to be used in the bioartificial liver (the experimentation plan of the lab work that I will hopefully do that my lecturer has wrote is on page 1 and 2), and how am I going to address the project aims and the hypothesis.
– For the hypothesis, please make sure to have justified the hypothesis, and ensure how the plan for my work will address the hypothesis. Therefore, make sure to not be too broad in the hypothesis, be specific about clear investigative methods, dependant and independent variables and has explanatory power. Make sure to not be too board in a way in which any results I provide could support it; it needs to be specific so only the actual specific results from the research plan will support it.

Leave a Reply