The use of biotechnology within medicine; diabetes and development of insulin using recombinant DNA technologies
Proteins act as a catalyst for metabolic reactions and responsible for inter and intracellular reactions and signalling events essential for life(Ferrer-Miralles, et al., 2009) Diabetes mellitus is a metabolic disorder with numerous aetiologies; it can be defined by chronic hyperglycaemia which will cause an effect on the metabolism of carbohydrates, fats and proteins. This detrimental effect is from the lack of insulin action, insulin secretion or a combination of them both. Diabetes causes long term damage, dysfunction and failure of a range of major organs. (Consulation, 1999) Through the use of clinical administration missing proteins can be sourced from external sources to reach normal concentrations within the tissular or systemic level. As a number of important studies have all confirmed the importance of the use of strengthened insulin treatment for the reduction and minimisation of long term diabetic complications; it is of great importance and pharmaceutical value that human proteins can be sourced (Lindholm, 2002) Through the use of biochemical and genetic knowledge the production of insulin has become available and this industrial scale of therapeutic protein production is the first true application of recombinant DNA technology. (Swartz, 2001, Walsh, 2003) E.coli can be considered as the first microorganism for the production of proteins and is primarily used for genetic modification, cloning and small-scale production for research purposes. Many historical developments within molecular genetics and microbial physiology have been based within this species which has results in a collection of both information and molecular tools. (Ferrer-Miralles, et al., 2009)
Proteins act as a catalyst for metabolic reactions and responsible for inter and intracellular reactions and signalling events essential for life; consequently , a deficiency in the production of polypeptides or production of non-functional of relevant proteins will derive in pathologies which can range from mild to severe (Ferrer-Miralles, et al., 2009).
Diabetes mellitus is a metabolic disorder with numerous aetiologies; it can be defined by chronic hyperglycaemia which will cause an effect on the metabolism of carbohydrates, fats and proteins. This detrimental effect is from the lack of insulin action, insulin secretion or a combination of them both. Diabetes causes long term damage, dysfunction and failure of a range of major organs. The characteristics presented with diabetes are weight loss, polyuria, blurring of vision and thirst; the more severe cases will cause ketoacidosis or a non-ketotic hypersmolar state which will lead onto comas, stupor and left untreated death. As the symptoms are often not severe and go undetected for long periods of time, hyperglycaemia can cause pathological and functional changes before a diagnosis can be made. Diabetes causes a multitude of long term affects which include, but not limited to; the failure of the renal system, a two to four times increased risk of cardiovascular disease and potential blindness. There are a number of pathogenetic processes which can be involved in the development of diabetes; these will include the processes which destroy the insulin creating beta cells within the pancreas and the creation of a resistance to insulin action ( Alberti, et al., 2006, Consulation, 1999)
A combination of metabolic disorders known as metabolic syndrome (MetS) is the combination of hyperglycaemia, hypertension and gout and other cardiovascular risk factors which predict a high risk of developing diabetes. People who have MetS are of the highest risk of the development of type 2 diabetes as it is present up to five times higher within people with this syndrome; this is due to the fact that glucose dysregulation is already present (Alberti, et al., 2006). Type 2 diabetes and atherosclerotic cardiovascular disease can be seen to be of similar ascendants. Inflammation markers have been associated with the development of type 2 diabetes in adults; although this may be part of the autoimmune response they will also reflect the pathogenesis (Schmidt, et al., 1999)
Abnormal metabolism of proteins, fats and carbohydrates is caused by the deficient insulin action on target tissues due to the insensitivity or lack of insulin. (Consulation, 1999) Through the use of clinical administration missing proteins can be sourced from external sources to reach normal concentrations within the tissular or systemic level. As a number of important studies have all confirmed the importance of the use of strengthened insulin treatment for the reduction and minimisation of long term diabetic complications; with human insulin being the first line of treatment; it is of great importance and pharmaceutical value that human proteins can be sourced, as this is difficult to do from natural sources (Lindholm, 2002) . We are far past the times of animal sourced insulin’s and we are reaching the turning point in the use of recombinant DNA technologies; which were developed during the late 70’s and uses E.coli as a biological framework for the production of proteins of interest through relatively inexpensive procedures. Recombinant DNA technology not only offers the ability to create straightforward proteins but also provides the tools to produce protein molecules with alternative and modified features. (Mariusz, 2011) There are several obstacles in the production of proteins through the use of E.coli however, as it lacks the ability to make post-translational modifications (PTMs) present within the majority of eukaryotic proteins (Ferrer-Miralles, et al., 2009). Recombinant DNA insulin’s are, therefore, gradually being replaced by the more highly efficient insulin analogues (Bell, 2007, Ferrer-Miralles, et al., 2009).
Clinically, insulin analogues have been used since the late 1990s, the reason behind insulin modification for subcutaneous injection is to produce absorption properties that better suit the rate of supply from the injection to the physiological need. (Jonassen, et al., 2012) Insulin analogues have the properties of being able to be either rapid acting such as glusine, aspart or lispro or be a long lasting molecule such as glargine and detemir, these can also be used in combination with protamine, these premixed insulin’s provide a more sustained action (Bell, 2007).
The combination of biotechnology and the pharmaceutical industry is a product of an evolution within technology and product innovation; which has become a result in advances within science and business practices. The biotechnology based products are thought of as intelligent pharmaceuticals as they often provide new modes and mechanisms in the action and approach to disease control with improved success rate and better patient care. (Evens & Kaitin, 2014) Through the use of biochemical and genetic knowledge the production of insulin has become available and this industrial scale of therapeutic protein production is the first true application of recombinant DNA technology. (Swartz, 2001, Walsh, 2003) Although, as insulin is required in such high volumes the product yields of the vast amount of the currently available secretory systems are not currently sufficient enough to make it fully competitive. The current ideas and strategies being used to help improve the efficiency and productivity of secretion are numerous. (Schmidt, 2004)
Cultivation of insulin can be done conveniently within microbial cells such as bacteria and yeast. During the 80’s the FDA approved the use of human insulin produced from recombinant E.coli for the treatment of diabetes, this was the first recombinant protein pharmaceutical to enter the market. Thanks to the versatility and possibilities created through the use of recombinant protein production a large sector of opportunities for pharmaceutical companies opened up. (Ferrer-Miralles, et al., 2009) Since the approval of insulin in 1982 there are now currently more than 200 biotech products available commercially and research has expanded this to over 900 products being tested within clinical trials. Pharmaceuticals are engaged within the development of these products substantially as well as their commercialisation (Evens & Kaitin, 2014). This acknowledges the fact that although the microbial systems lack the post translational modifications they are able to efficiently and conveniently produce functional mammalian recombinant proteins. Specific strains of many microbial species have now been created and adapted towards protein production; and the incorporation of yeasts and eukaryotic systems is now in place for protein production. (Ferrer-Miralles, et al., 2009).
The use of E.coli expression system is the preferable choice for production of therapeutic proteins, amongst the 151 pharmaceuticals licensed in January 2009 30% where obtained in E.coli, this is due its ability to allow for efficient and economical production of proteins on both a lab scale and within industry (Mariusz, 2011, Swartz, 2001). During insulin production within E.coli the gene is fused with a synthetic fragment encoding for two IgG binding domains which have been derived from staphylococcal protein A. This product is then secreted into the growth medium of E.coli and purified using the IgG affinity. (Moks, et al., 1987)
E.coli can be considered as the first microorganism for the production of proteins and is primarily used for genetic modification, cloning and small-scale production for research purposes. Many historical developments within molecular genetics and microbial physiology have been based within this species which has results in a collection of both information and molecular tools. (Ferrer-Miralles, et al., 2009) E.coli flourishes at a temperature of 37°C but the proteins are in insoluble form. Fusion protein technology has been able to increase the solubility of over expressed proteins, through the modification of selected amino acid residues allowing for the collection of soluble proteins (Zhang, et al., 1998).
Due to the lack of the mechanisms to enable PTMs in bacterial cells protein maturation and disulfide bridges can be, to an extent overcome through the use of protein engineering (Mariusz, 2011). PTMs are crucial in protein folding, stability, processing and activity; therefore, proteins lacking the PMTs may be unstable, insoluble or inactive. However it is possible to synthetically bind PTMs to products, and through genetic engineering of DNA, the amino acid sequence of the polysaccharide can be changed to alter its properties this has been observed within insulin. (Ferrer-Miralles, et al., 2009) For more sophisticated modifications the genetic fusion of two proteins is required (Mariusz, 2011) An increase number of proteins being produced are engineered and tailored to display altered pharmacokinetic profiles and reduce immunogenicity. (Walsh, 2003)
Even with the pharmaceutical market progressively producing more protein drugs from non-microbial systems; cell-free protein synthesis and oxidative cytoplasmic folding offers alternatives to the standard recombinant production techniques, it has not effect or impaired the development and progression of products developed within microbial systems proving the robustness of the microbial systems. (Ferrer-Miralles, et al., 2009, Swartz, 2001)
In the future Radio Frequency Identification technology will play an important role; however there are some barriers in place for the pharmaceutical supply chain, as there have been concerns raised concerning the potential detrimental effect on the proteins due to the electromagnetic exposure. Alterations have been detected after the RFID however the effect and damages to the protein remain unknown (Acierno, et al., 2010)
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