Diabetes – I is for Injections

It was on January 23rd 1922 that Insulin injections were used for the first time to treat a Diabetic patient.

Before then, Diabetes was a much feared disease that almost certainly resulted in early death. The elevated levels of blood glucose in diabetic patients resulted in gradual failure of the body’s various organs – and in those days the only effective “treatment” was to place these people on very strict diets keeping their sugar intake to a minimum. At best, this sort of therapy might have bought such patients a few extra years of life, but it could never cure them – or allow them to lead “normal” lives.

In May 1921 a Canadian surgeon Frederick Banting and his research assistant medical student Charles Best began a series of experiments on dogs in an attempt to find a treatment for Diabetes. Using the pancreas organs of these experimental animals, they identified a promising extract from the Islet cells of the pancreas which they showed could reduce blood sugar levels. The third member of their team, biochemist James Collip helped to purify the extract and increase its potency.

Banting and Best first tried injecting their extract (which they named Insulin after the Latin word Insula meaning ‘island’) into diabetic dogs – and then, finding that it worked on the animals, they even tried it on themselves! Satisfied that the new extract would work, they finally chose a 14 year old diabetic boy, Leonard Thompson as the first diabetic who would receive Insulin. On January 23rd 1922 they gave him the first injection of Insulin in an attempt to treat his Diabetes.

Banting and Best’s experiment – for that is what this first use of the new drug on a human subject was – succeeded!  The diabetic teenager, who before receiving the injections of Insulin was near death, rapidly regained his strength and appetite. The team now gave the new drug to other volunteer diabetics, who responded equally well.

From that beginning, Insulin has revolutionised the management of Diabetes. Unfortunately, insulin cannot be taken in tablet form, because once it enters the intestine, it is broken down – digested in fact – and becomes ineffective. To function as Insulin, it has to be injected directly into the body tissues. This is why researchers have spent so much effort in trying to identify substances that could be taken in tablet form, because, effective though Insulin is, nobody likes to have to inject themselves every day to keep their blood sugar under control.

Today we have several forms of insulin – some acting rapidly to bring down blood sugar levels and others that are longer lasting, so that taken just once a day they can keep blood glucose levels within the normal range. Which particular form of insulin is best for you is a decision that you and your doctor have to work out.

More recently, in addition to Insulin, we have a new injection that can be used to treat diabetes. Similar to the Incretin based oral medications discussed last month, drugs such as Exanetide (Byetta) and Liraglutide (Victoza) are synthetic forms of glucagon-like peptide (GLP-1). They are similar to insulin in that they cannot be taken by mouth and have to be injected. Research has shown that these GLP-1 mimetics can reduce HbA1C (three monthly average blood sugar levels) by up to 2% – and they have the additional benefit of being associated with weight loss.

Most importantly, they act to reduce blood sugar only in response to excess sugar entering the blood stream from the gut. They are relatively inactive otherwise, so the risk of pushing blood sugar levels too low (hypoglycaemia) is minimal.