Artificial cells containing cells

The first artificial cells containing intact biological cells were reported in 1964 based on a drop method (Chang, 1964), and it was proposed that "protected from immunological process, encapsulated endocrine cells might survive and maintain an effective supply of hormone" (1965, Chang et al., 1966) (Fig. 2.5).

Chang asked Conaught Laboratory of insulin fame to develop this for use in islet transplantation for diabetes. Later, Sun and his collaborator from Conaught Laboratory developed Chang's original drop method (Chang, 1964,1965,1972a; Chang et al., 1966), using alginate-polylysine-alginate (APA) for the artificial cell membranes (Lim and Sun, 1980). They showed that after implantation, the insulin secreting islets inside the artificial cells indeed remained viable and continued to secrete insulin to control the glucose levels of diabetic rats (Lim and Sun, 1980).

We have been studying the use of artificial cells containing liver cells (hepatocytes) for liver support. Implanting these increases the

Fig. 2.5. Upper: Problems related to injection of free cells. Middle: Cells inside larger artificial cells no longer have these problems when injected. Lower: Artificial cells containing biological cells. Priniciple has been extended and used by many groups for bioencapsulation of islets, cells, genetically-engineered cells and stem cells (Chang, Nature Rev. Drug Discovery, 2005).

Fig. 2.5. Upper: Problems related to injection of free cells. Middle: Cells inside larger artificial cells no longer have these problems when injected. Lower: Artificial cells containing biological cells. Priniciple has been extended and used by many groups for bioencapsulation of islets, cells, genetically-engineered cells and stem cells (Chang, Nature Rev. Drug Discovery, 2005).

survival of acute liver failure rats (Wong and Chang 1986); lowers the high bilirubin level in congenital Gunn rats (Bruni and Chang, 1989); and prevents xenograft rejection (Wong and Chang, 1988). We developed a two-step cell encapsulation method to improve the APA method, resulting in improved survival of implanted cells (Wong and Chang, 1991a). Cell bioencapsulation for cell therapy has been extensively developed by many other groups especially using artificial cells containing endocrine tissues, hepatocytes, genetically-engineered cells and stem cells (Orive etal., 2002; Chang, 2005). This is a very broad area that will be described in much more detail in the later chapters. Below is a brief introduction to the use of this principle for stem cells and genetically-engineered cells.

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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