diabetes

Question 1

define diabetes

Answer 1

Diabetes mellitus is a chronic condition affecting the body’s ability to regulate blood glucose levels. There are two main types, though both are characterized by high blood glucose levels (hyperglycaemia), which reflects insufficient action of the hormone insulin

Question 2

what are common symptoms of diabetes

Answer 2

Common symptoms are excessive secretion of urine (polyuria), excessive thirst (polydipsia), weight loss and tiredness. However, in type 2 diabetes it may be that the patient is asymptomatic for some time and the disease is diagnosed several years later, by which time complications are already present.

Question 3

what is type 1 diabetes

Answer 3

In type 1 diabetes, the β-cells in the pancreas are unable to produce enough insulin, and in some cases are not able to produce any at all.

Question 4

how is type 1 diabetes an autoimmune disease

Answer 4

Type 1 diabetes arises as a result of the body’s immune system attacking the person’s own β-cells, having recognised their self-antigens as foreign. This is autoimmunity.

Question 5

what may be a cause of developing type 1 diabetes

Answer 5

It may be that this is triggered by the person acquiring a viral infection in which the viral antigens are similar to those specific to the β-cells in the islet of langerhams, and so the immune response is to destroy these cells as if they were a pathogen.

Question 6

why does the attack on the beta cells cause diabetic symptoms in type 1 diabetes

Answer 6

As the β-cells are those responsible for producing insulin, the body is not able to effectively control blood glucose levels with the loss of β-cells. When blood glucose levels increase, for example after a meal, the body can’t produce enough insulin, which is responsible for stimulating the uptake of glucose into cells so that the blood-glucose levels are able to fall back to the base level. This results in hyperglycaemia.

Question 7

what percentage of cases of diabetes does type 2 account for

Answer 7

type 2 accounts for around 90% of all cases of diabetes.

Question 8

what plays a major role in the onset of type 2 diabetes, and what factors are associated with it

Answer 8

Insulin resistance plays a major role in the onset of type 2 diabetes, which is often associated with obesity and poor diet.

Question 9

what does insulin resistance happen

Answer 9

Insulin resistance happens when the β-cells secrete the correct amount of insulin but the tissues of the body do not respond to it properly. This results in the blood glucose levels of the body rising, which causes the β-cells to produce even more insulin as a homeostatic response. Eventually the β-cells start to lose their ability to produce insulin at such high rates to keep up with the high blood glucose levels, and so the affected person’s blood glucose concentration increases substantially.

Question 10

what are many of the symptoms of diabetes a result of

Answer 10

Many of the symptoms of diabetes are caused by the kidney not being able to reabsorb the high concentrations of glucose in the blood, and so glucose is excreted in the urine. The presence of glucose in the urine increases the osmolarity of the urine, which causes more water to be lost via the kidney into the urine. Symptoms such as polyuria and polydipsia result from this. Tiredness and dry skin are also caused by long-term dehydration.

Question 11

how has the number of people diagnosed with diabetes in the UK changed in the last 20 years, and what does this parallel

Answer 11

In the past twenty years, the number of people diagnosed with diabetes in the UK has more than doubled. This great increase parallels the increasing incidence of obesity in the UK, which is the leading cause in the majority of preventable cases of type 2 diabetes.

Question 12

what has been the percentage increase in adult obesity in 20 years

Answer 12

In 20 years, the UK has seen a 380% increase in adult obesity, from only 8% in 1980 to around 33% in 2010.

Question 13

what proportion of type 2 diabetes cases could be prevented or delayed by a change in lifestyle

Answer 13

Three in five cases of type 2 diabetes could be prevented or delayed by a change in lifestyle towards healthier eating and more physical activity.

Question 14

how many people is it estimated to have a significant increased risk of developing type 2 diabetes, and how could this be reduced

Answer 14

It is estimated that in the UK there are around 12.3 million people who have a significant increased risk of developing type 2 diabetes.
By making people aware of their own risk and how it can be reduced, and by ensuring an early diagnosis for people who are known to have a high risk of developing the condition, the number of preventable cases should decrease.

Question 15

who uses insulin injections as a treatment

Answer 15

People with type 1 diabetes must take insulin (often in the form of injections or a pump) in order to control their blood glucose levels. Some cases of type 2 diabetes may also be treated with insulin injections as well. Approximately 90% of those with type 1 diabetes in the UK inject insulin in the form of multiple daily injections

Question 16

what is the most common way of treating diabetes with insulin injections

Answer 16

The great majority of people treating their diabetes with insulin injections follow a basal-bogus regime, which involves taking two types of insulin in multiple daily injections. A long-acting form of insulin is taken once or twice a day to maintain stable blood glucose levels when the person is not eating. A rapid-acting form of insulin is also taken before each meal to prevent rises in blood glucose concentrations following the intake of carbohydrates. This normally totals to taking 4-8 injections a day.

Question 17

give history of insulin treatments

Answer 17

Insulin was first commercialised over almost 100 years ago, in the form of cow insulin.

Question 18

describe the early changes to insulin treatments and why they happened

Answer 18

As three of the 51 amino acids in insulin are different in cow insulin compared to that of humans, the action of cow insulin differed slightly to human insulin and caused some patients to have allergic reactions. Pig insulin soon started to be marketed, and as there is only one amino acid that is different between pig and human insulin, it acted as a much better replacement and lead to fewer allergic reactions.

Question 19

how has insulin been made long-acting as an improvement

Answer 19

The use of insulin as a treatment as since been improved, for example by delaying the absorption and prolonging the action of the insulin by mixing it with a basic protein called protamine, forming a long-acting insulin formula.

Question 20

when was human insulin first produced in a lab

Answer 20

In 1978, human insulin was first produced in a laboratory using recombinant DNA technology.

Question 21

outline the process of producing human insulin in a laboratory using recombinant DNA technology.

Answer 21

The single mammalian gene that causes the synthesis of proinsulin is transfected into a plasmid (a loop of bacterial DNA), which is inserted back into bacteria that are grown in fermentation tanks and the insulin that they produce is harvested and purified for use as a medicine.

Question 22

apart from insulin what other medications can treat diabetes

Answer 22

For decades, the only injectable diabetes medication was insulin. However, since 2005, several more have come onto the market, including a class of medications known as incretin mimetics, which are used for the treatment of type 2 diabetes.

Question 23

how do incretin mimetics work

Answer 23

These medications work by increasing the levels of incretins inside the body.[9] Incretins are hormones that are released by endocrine cells in the epithelium of the small intestine, when the presence of food in the lumen is detected.[10] One of their many physiological roles is to regulate the amount of insulin that is secreted after eating. One of the roles of incretins is to regulate the amount of insulin that is secreted after insulin, and this insulin secretory response of incretins accounts for at least 50% of the total insulin secreted after oral glucose. Despite a lack of secretion or an increase in the deactivation of incretins not playing a role in the pathogenesis of diabetes, however in type 2 diabetes, one of the two incretins, GIP, is found to no longer modulate glucose-dependent insulin secretion. The other incretin, GLP-1, is still insulinotropic (i.e. induces insulin secretion) in type 2 diabetes, and this has lead to the development of medications act to improve insulin secretion by activating the GLP-1 receptor. Drugs based on incretin action include incretin mimetics (agonists of the GLP-1 receptor) and incretin enhancers (which inhibit DPP4 – the enzyme that rapidly deactivates incretins in the typical physiological response). [11]

Question 24

what are other treatments that are being developed to treat diabetes

Answer 24

Other treatments, such as stem cell therapies and islet cell transplants are being developed. As a means to ‘reset’ the immune system so that the β-cells are no longer under attack from the body, stem cells derived from the patient’s bone marrow are collected from the blood while they undergo chemotherapy to party destroy the patient’s own bone marrow cells.

Question 25

what was the outcome of the trial of using chemotherapy to treat diabetes

Answer 25

This is a procedure that is usually used to treat patients with diseases of the blood, such as leukaemia. The volunteers in this study were able to go an average of two and a half years without the multiple daily injections they previously needed to manage their condition. However, in the treatment and follow-up of the study, two volunteers developed bilateral pneumonia and after more than a year three patients had developed problems with endocrine function (mainly thyroid problems). Nine of the volunteers developed extremely low sperm counts, becoming ‘sub-fertile’. [12]

Question 26

describe the development of islet transplants to treat diabetes

Answer 26

The UK launched the world’s first government-funded islet transplant programme in 2008, and the transplants are now available on the NHS. Healthy islet cells are extracted from the pancreas of a deceased donor and are transplanted into the liver of a type 1 diabetes patient. It is a minor procedure that can be carries minimal risk using a needle with the recipient under local anaesthetic. [13] The healthy beta cells are injected into a vein that carries blood to the liver, where they begin to make and release insulin in the patient’s body. The islet transplantations can greatly decrease the incidence of severe hypoglycaemic episodes, and mean that the recipient has less or no need for daily insulin injections. However, the recipient has to take immunosuppressants to reduce the likelihood of their body attacking and destroying the transplanted islet cells.