Team:Slovenia/ImplementationHepatitisC

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<h1>Hepatitis C</h1>
<h1>Hepatitis C</h1>
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<p>We designed a device for the therapy of hepatitis C, composed of microencapsulated mammalian cells that include a genetic bistable toggle switch with a positive feedback loop, where in one state the cells produce interferon alpha (IFN-α) as the antiviral effector and in the second state they produce <b>hepatocyte growth factor (HGF)</h> to promote liver regeneration.</p>
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<p>We designed a device for the therapy of hepatitis C, composed of microencapsulated mammalian cells that include a genetic bistable toggle switch with a positive feedback loop, where in one state the cells produce interferon alpha (IFN-α) as the antiviral effector and in the second state they produce hepatocyte growth factor (HGF) to promote liver regeneration.</p>
<p>A pharmacokinetic model demonstrated that if the device is implanted into the liver it results in higher levels of IFN-α within the liver than systemically. More importantly, this type of application avoids the spikes of high IFN-α concentration that occur in treatment with IFN-α injections. This should decrease the severity of side effects of IFN-α experienced by a high percentage of patients.</p>
<p>A pharmacokinetic model demonstrated that if the device is implanted into the liver it results in higher levels of IFN-α within the liver than systemically. More importantly, this type of application avoids the spikes of high IFN-α concentration that occur in treatment with IFN-α injections. This should decrease the severity of side effects of IFN-α experienced by a high percentage of patients.</p>
<p>We estimated, based on the detection of IFN-α produced by HEK293 cells, that sufficient quantities of the therapeutic protein could be produced by the amount of microencapsulated cells feasible in a real therapeutic application.</p>
<p>We estimated, based on the detection of IFN-α produced by HEK293 cells, that sufficient quantities of the therapeutic protein could be produced by the amount of microencapsulated cells feasible in a real therapeutic application.</p>
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<h3>Implementation of the microencapsulated synthetic cellular device for the therapy of hepatitis C</h3>
<h3>Implementation of the microencapsulated synthetic cellular device for the therapy of hepatitis C</h3>
<p>With our biological delivery system we aim to overcome some of the adverse effects of the IFN therapy and make the therapy more efficient and affordable. Because of the local (intrahepatic/intraperitoneal) production of IFN-α from the cell-delivery system, a lower systemic concentration is expected, which could diminish systemic side effects. Furthermore, because repetitive subcutaneous application would no longer be needed, the quality of life of patients would improve as well as compliance to the therapy.</p>
<p>With our biological delivery system we aim to overcome some of the adverse effects of the IFN therapy and make the therapy more efficient and affordable. Because of the local (intrahepatic/intraperitoneal) production of IFN-α from the cell-delivery system, a lower systemic concentration is expected, which could diminish systemic side effects. Furthermore, because repetitive subcutaneous application would no longer be needed, the quality of life of patients would improve as well as compliance to the therapy.</p>
-
<p>In addition to antiviral activity the design of our system allows us to include additional effector proteins in the therapy. Since the advanced stages of hepatitis seriously damage the liver, we decided to include a therapeutic drug to improve liver regeneration. Hepatocyte growth factor (HGF) is a paracrine cellular growth, motility and morphogenic factor secreted by mesenchymal cells. It targets and acts primarily upon epithelial and endothelial cells, but also acts on haemopoietic progenitor cells. It has been shown to have a major role in adult organ regeneration and in wound healing. HGF induces proliferation and regeneration of hepatocytes, and its application by gene therapy in several preclinical studies has <b>inhibited fibrogenesis and hepatocyte apoptosis and produced the complete resolution of fibrosis in the cirrhotic liver</b> (Ueki et al., 1999). The inclusion of HGF to the interferon therapy of hepatitis C could improve liver regeneration as HGF also promotes differentiation of stem cells into hepatocytes (Oyagi et al., 2006, Nakamure ate al., 2011).</p>
+
<p>In addition to antiviral activity the design of our system allows us to include additional effector proteins in the therapy. Since the advanced stages of hepatitis seriously damage the liver, we decided to include a therapeutic drug to improve liver regeneration. <b>Hepatocyte growth factor (HGF)</b> is a paracrine cellular growth, motility and morphogenic factor secreted by mesenchymal cells. It targets and acts primarily upon epithelial and endothelial cells, but also acts on haemopoietic progenitor cells. It has been shown to have a major role in adult organ regeneration and in wound healing. HGF induces proliferation and regeneration of hepatocytes, and its application by gene therapy in several preclinical studies has <b>inhibited fibrogenesis and hepatocyte apoptosis and produced the complete resolution of fibrosis in the cirrhotic liver</b> (Ueki et al., 1999). The inclusion of HGF to the interferon therapy of hepatitis C could improve liver regeneration as HGF also promotes differentiation of stem cells into hepatocytes (Oyagi et al., 2006, Nakamure ate al., 2011).</p>
<p>We adapted our therapeutic device for the therapy of HCV infection to include the coding regions for IFN-alpha2 and HGF coupled via a t2a peptide sequence to the activators TALA and TALB of our bistable toggle switch with a positive feedback loop. This arrangement allows the initial production of IFN-α to treat the viral infection, and an induced switch to the second state after the virus has been cleared allows improved liver regeneration with HGF production.</p>
<p>We adapted our therapeutic device for the therapy of HCV infection to include the coding regions for IFN-alpha2 and HGF coupled via a t2a peptide sequence to the activators TALA and TALB of our bistable toggle switch with a positive feedback loop. This arrangement allows the initial production of IFN-α to treat the viral infection, and an induced switch to the second state after the virus has been cleared allows improved liver regeneration with HGF production.</p>
<h2>Pharmacokinetic modeling of the distribution of IFN-α in the therapy</h2>
<h2>Pharmacokinetic modeling of the distribution of IFN-α in the therapy</h2>

Revision as of 11:57, 26 September 2012


Hepatitis C

We designed a device for the therapy of hepatitis C, composed of microencapsulated mammalian cells that include a genetic bistable toggle switch with a positive feedback loop, where in one state the cells produce interferon alpha (IFN-α) as the antiviral effector and in the second state they produce hepatocyte growth factor (HGF) to promote liver regeneration.

A pharmacokinetic model demonstrated that if the device is implanted into the liver it results in higher levels of IFN-α within the liver than systemically. More importantly, this type of application avoids the spikes of high IFN-α concentration that occur in treatment with IFN-α injections. This should decrease the severity of side effects of IFN-α experienced by a high percentage of patients.

We estimated, based on the detection of IFN-α produced by HEK293 cells, that sufficient quantities of the therapeutic protein could be produced by the amount of microencapsulated cells feasible in a real therapeutic application.

Figure 1. Therapy of hepatitis C by microencapsulated cells which can be regulated to produce and release therapeutic proteins into the liver tissue.

Figure 2. Scheme of the constructs for the regulated therapy of hepatitis C with interferon alpha (IFN-α) and hepatocyte growth factor (HGF). Each of the therapeutic effector is released in equimolar amount to the autoactivator.

Hepatitis C virus infection

Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) which primarily infects the liver. Hepatitis C is a serious worldwide health problem with a prevalence of 3% in the world’s population. According to WHO, 170 million individuals are infected with an incidence of 3 to 4 million new cases per year. More than 350,000 people die yearly from hepatitis C-related diseases. In the US the HCV has surpassed HIV as a cause of death. Medical care costs associated with treatment of HCV infection are estimated to be more than $600 million per year just in the USA.

Figure 3. Hepatitis C prevalence (http://en.wikipedia.org/wiki/File:HCV_prevalence_1999.png).

HCV accounts for 20% of all cases of acute hepatitis which is usually asymptomatic. In approximately 75% – 85% of patients, HCV persists as a chronic infection, placing infected persons at risk for developing chronic liver disease. The risk of liver cirrhosis after 20 years of persistent hepatitis C infection is approximately 10-15% for men and 1-5% for women. Once cirrhosis is established, the rate of developing liver cancer is 1 to 4% per year (Pawlotsky, 2004). It is the most common indication for orthotopic liver transplantation in the United States.

Hepatitis C virus is a small, spherical, enveloped, single-stranded RNA virus, a member of the Flaviviridae family. Because the HCV RNA-dependent RNA polymerase lacks proofreading capabilities, it generates a large number of mutant viruses known as quasispecies when the virus replication takes place. These HCV quasispecies represent a major challenge to immune-mediated control of HCV and may explain the difficulties in vaccine development.

Current therapy

Patients with acute hepatitis C virus infection which has not resolved after 2-4 months are treated with standard interferon (IFN) therapy for 6 months. Treatment of chronic HCV infection has 2 goals: sustained eradication of HCV and prevention of chronic complications. IFN-α has been used since the 1980s in the treatment of chronic hepatitis and still represents an important part of the management of chronic hepatitis C infection. Initial studies used IFN-α monotherapy, but current treatments are a combination therapy consisting of ribavirin and IFN-alpha (Feld and Hoofnagle, 2005). Side effects of treatment are very common, with half of the patients suffering from flu like symptoms and a third experiencing emotional problems. Anxiety, sleep disorders and irritability are frequently observered and can in some cases lead to severe behavioral or psychological disorders. This can in turn lead to the discontinuation of therapy.

Implementation of the microencapsulated synthetic cellular device for the therapy of hepatitis C

With our biological delivery system we aim to overcome some of the adverse effects of the IFN therapy and make the therapy more efficient and affordable. Because of the local (intrahepatic/intraperitoneal) production of IFN-α from the cell-delivery system, a lower systemic concentration is expected, which could diminish systemic side effects. Furthermore, because repetitive subcutaneous application would no longer be needed, the quality of life of patients would improve as well as compliance to the therapy.

In addition to antiviral activity the design of our system allows us to include additional effector proteins in the therapy. Since the advanced stages of hepatitis seriously damage the liver, we decided to include a therapeutic drug to improve liver regeneration. Hepatocyte growth factor (HGF) is a paracrine cellular growth, motility and morphogenic factor secreted by mesenchymal cells. It targets and acts primarily upon epithelial and endothelial cells, but also acts on haemopoietic progenitor cells. It has been shown to have a major role in adult organ regeneration and in wound healing. HGF induces proliferation and regeneration of hepatocytes, and its application by gene therapy in several preclinical studies has inhibited fibrogenesis and hepatocyte apoptosis and produced the complete resolution of fibrosis in the cirrhotic liver (Ueki et al., 1999). The inclusion of HGF to the interferon therapy of hepatitis C could improve liver regeneration as HGF also promotes differentiation of stem cells into hepatocytes (Oyagi et al., 2006, Nakamure ate al., 2011).

We adapted our therapeutic device for the therapy of HCV infection to include the coding regions for IFN-alpha2 and HGF coupled via a t2a peptide sequence to the activators TALA and TALB of our bistable toggle switch with a positive feedback loop. This arrangement allows the initial production of IFN-α to treat the viral infection, and an induced switch to the second state after the virus has been cleared allows improved liver regeneration with HGF production.

Pharmacokinetic modeling of the distribution of IFN-α in the therapy

Consultation with Peter Popovič, MD, Msc, an interventional radiologist, suggested that microcapsules could be applied to the liver artery via a catheter to distribute production of IFN-α and later HGH throughout the liver.

References

Banfi, A., von Degenfeld, G., Gianni-Barrera, R., Reginato, S., Merchant, M.J., McDonald, D.M., and Blau, H.M. (2012) Therapeutic angiogenesis due to balanced single-vector delivery of VEGF and PDGF-BB. FASEB J. 26, 2486-2497.

Ortiz, L.A., Dutreil, M., Fattman, C., Pandey, A.C., Torres, G., Go, K., and Phinney, D.G. (2007) Interleukin 1 receptor antagonist mediates the antiinflammatory and antifibrotic effect of mesenchymal stem cells during lung injury. Proc. Natl. Acad. Sci. U S A 104, 11002-11007.

Szymczak, A.L., Workman, C.J., Wang, Y., Vignali, K.M., Dilioglou, S., Vanin, E.F., Vignali D.A. (2004) Correction of multi-gene deficiency in vivo using a single 'self-cleaving' 2A peptide-based retroviral vector. Nat. Biotechnol. 22, 589-94.


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