Bernie Tuch, Brisbane Times.

Diabetes affects 140,000 young Australians, who would die unless they received multiple insulin injections each day of their lives. The cause is the self-destruction of the insulin-producing cells within the pancreas.

Attempts have been made recently to replace these cells with surrogates, allowing recipients to cease injecting insulin. The source of the replacement cells is a pancreas donated after death. But organ supply is limited, with as few as 200 donors in Australia a year.

Stem cells are a potential alternative source of insulin-producing cells. The stem cells come from embryos, cord blood or from adults, for example from the nose. At present, none of these cells can be differentiated into insulin-producing cells that are the same as those found in a normal pancreas.

It is a quest of many to produce such cells in the numbers required to allow people with diabetes to cease insulin injections.

In travelling this road, it is important to leave no stone unturned, but at the same time provide realistic hope to those waiting to receive a benefit. Life for many people with insulin-dependent diabetes is incapacitating. Blood glucose levels should not rise into the coma range but also should not become too low such that unconsciousness ensues.

Possible therapies being trialled are just that, possible. Last month a publication from Brazil showed a benefit when adult stem cells derived from blood were given to certain newly diagnosed people with diabetes, who were also given drugs to block their immune system. The trial lacked biological controls, so it is uncertain whether the benefit was due to the stem cells, the immunosuppressant drugs, natural recovery of the person's own insulin-producing cells or a combination of these factors. It is misleading to hold out this promising area of research as "momentous" at this early stage when the risk to the recipient, from infection, is quite high.

Embryonic stem cells hold out great hope as a therapy for insulin-dependent diabetes because of the potential of these cells to develop into any cell type. Adult stem cells, by definition, have slightly less potential, since they are more developed, but can still be converted into many but not all cell types. Research is a slow process, often taking several decades to produce outcomes. Thus, the first person to cease insulin on receiving donor human insulin-producing cells did so after 15 years of solid research. It took a further 10 years of research before success rates with this treatment improved. Research into converting human embryonic and adult stem cells into insulin-producing cells has been occurring for less than a decade. It is unrealistic to expect clinical outcomes so soon.