Diabetes Mellitus

• Type 1 Diabetes

  • Cause:
  • Immune system attacks β cells in islets of Langerhans
  • Autoimmune disease
  • Genetic or due to viral infection
  • Effect:
  • β cells in pancreas no longer secrete insulin
  • Consequence:
  • After eating blood sugar levels heighten - hyperglycaemia
  • Kidneys can't reabsorb all glucose
  • Too high lead to coma or death
  • Symptoms:
  • Glucose in urine
  • Thirstier
  • Dry mouth
  • Frequent urination
  • Tiredness
  • Unintentional weight loss
  • Treatment:
  • Insulin therapy
  • Inject regularly through day after food
  • Careful control - injecting too much cause dangerous drop
  • Insulin pump
  • Small device, constantly pumps insulin at controlled rate
  • Some have patch sensors monitor blood sugar levels + send pump a message
  • Islet cell transplantation
  • Complete pancreas transplant
  • Potentially stem cells to grow new islets of Langerhans
• Type 2 Diabetes

  • Cause:
  • β cells in islets of Langerhans don’t produce enough insulin or body’s cells respond wrong
  • Due to fat around organs
  • Poor diet, low exercise + age, asian or afro-caribbean origin or family history
  • Effect:
  • Insulin receptors on target cells don’t work properly
  • Cells won't take up enough glucose
  • Consequence:
  • Blood glucose conc higher than normal
  • Symptoms:
  • Urinating more than usual, particularly at night, feeling constant thirst, feeling very tired, losing weight without trying and cut/wounds taking longer to heal
  • Treatment:
  • Lifestyle changes - e.g. balanced diet or regular exercise
  • Glucose-lowering medication
  • Take insulin or pancreas transplant would be ineffective as cells do not respond to insulin
• Insulin Sources

  • Traditionally, insulin from pig pancreas was used, it matches human insulin closely
  • More recently, human insulin produced by genetically modified Escherichia coli bacteria
  • Genetically engineered bacteria; DNA altered + human insulin gene inserted
  • Advantages
  • Exact copy of human insulin; faster acting + more effective
  • Less chance of developing insulin tolerance
  • Less chance of rejection due to immune response
  • Lower infection risk
  • Cheaper to manufacture insulin than extract it from animals
  • Manufacturing process is more adaptable to demand
  • Less moral objections of insulin produced by bacteria than that extracted from animals
  • Stem cells
  • Possible to treat Type 1
  • Inject into pancreas
  • Scientists found precursor cells in adult mice pancreas
  • If similar cells in human pancreas, could be used to make new beta cells
  • Give patient freedom from daily injections