Diabetes and Blood Glucose Regulation

Blood Glucose and Insulin Levels

• Blood glucose levels fluctuate throughout the day, peaking after meals.
• Insulin levels are also altered, with higher levels following meals to regulate glucose.
• Starch-rich foods cause a more pronounced increase in blood glucose compared to sucrose-rich foods.
• The graph demonstrates the different responses of glucose and insulin levels to meals (breakfast, lunch, and dinner) over a 24-hour period.

Oral Glucose Tolerance Test

• The oral glucose tolerance test compares blood glucose responses in normal and diabetic individuals.
• The diabetic subject has a much higher increase in glucose from baseline compared to a normal subject.
• The diabetic response takes a greater amount of time to return to baseline.

Diabetes Criteria

• The 2017 ADA Guidelines for diabetes diagnosis do not differentiate between types 1 and 2.
• Criteria include:
  • Hemoglobin A1c greater than 6.5%
  • Fasting glucose greater than 126 mg/dL
  • Two-hour postprandial glucose in an oral glucose tolerance test ≥200 mg/dL
  • Random plasma glucose ≥200 mg/dL in a patient with classic symptoms of hyperglycemia or hyperglycemic crisis.

Hemoglobin A1c

• Hemoglobin A1c is used to diagnose and monitor diabetes.
• Glycated hemoglobin shows the average blood glucose levels over the past three months.
• A hemoglobin A1c of 6.5% or above signifies type 2 diabetes.

Type 1 Diabetes

• Over 90% of recently diagnosed type 1 diabetics have measurable antibodies against specific beta-cell proteins.
• Symptoms of diabetes are not always immediately apparent with one auto-antibody.
• Two or more autoantibodies significantly increase the risk of developing type 1 diabetes before age 18.

Development of Type 1 Diabetes

• The development of the disease is linked to the presentation of beta-cell peptides by antigen-presenting cells (APCs).
• Autoreactive CD8+ T cells activated by these interactions lyse beta cells.
• Proinflammatory cytokines and reactive oxygen species exacerbate beta-cell destruction.
• Regulatory T lymphocytes fail to effectively suppress.

Diabetic Ketoacidosis (DKA)

• DKA results from overproduction of ketone bodies due to insulin deficiency or resistance
• Symptoms of DKA include dehydration, confusion, nausea, vomiting, abdominal pain, and rapid deep breathing to compensate for the acidosis.
• Insulin therapy is used to resolve DKA.

Pathophysiology Map

• A pathophysiology map illustrates how insulin deficiency due to beta-cell destruction leads to various metabolic abnormalities, including ketoacidosis, hyperglycemia, and polyuria.
• The map visually represents the relationship between various physiological pathways.

Insulin for Treating Type 1 Diabetes

• Different types of insulin vary in their onset, peak, and duration of action, impacting when and how they are administered.
• Rapid-acting insulins have a quick onset and are used immediately before meals
• Regular insulins are utilized before meals.
• Long-acting insulins have a delayed but sustained effect. They are usually used once a day.

Insulin for Treating Type 1 Diabetes (Continued)

• Intensive insulin therapy involves multiple daily injections or an insulin pump which may use continuous glucose monitoring (CGM).
• Basal insulin supports continuous levels in the body, while meal-time or bolus doses manage carbohydrate intake in meals.

Type 2 Diabetes Drugs

• Metformin reduces sugar production and improves insulin sensitivity.
• Insulin-releasing pills (secretagogues), such as sulfonylureas, increase insulin release from the pancreas.
• SGLT2 inhibitors slow glucose absorption in the kidneys.
• Other medications like incretin based therapies and Amylin analogs, adjust glucose production and/or absorption, influencing glucose levels.

Insulin Secretagogues

• Insulin secretagogues are medications used to treat type 2 diabetes by stimulating insulin release when beta cells can no longer adapt to higher glucose levels.
• Sulfonylureas, a common type of secretagogue, can cause hyperinsulinemia and thus increase the risk of hypoglycemia.

SGLT2 Inhibitors

• SGLT2 inhibitors are medications that promote glucose excretion in the urine by blocking glucose reabsorption in the kidneys.
• These medications effectively lower blood glucose but have side effects like genital infections and DKA.

Incretins (GLP1)

• Incretins, such as GLP-1, are hormones released by the gut in response to nutrient ingestion.
• GLP-1 activates the GLP-1 receptor to increase insulin secretion, decrease glucagon secretion, and enhance beta-cell function.
• GLP-1 also reduces gastric emptying, slowing digestion, and lowering appetite.
• Drugs that inhibit the DPP4 enzyme that breaks down GLP-1 lead to more time for its function, enhancing it.

Amylin Analogs

• Amylin, a co-secreted peptide with insulin, slows gastric emptying, thereby delaying the appearance of glucose from a meal into the bloodstream.
• It inhibits postprandial glucagon secretion and promotes satiety, helping manage blood glucose levels.

Weight Regain

• Weight loss interventions often lead to rapid weight loss followed by a plateau phase and then regain of lost weight over time.
• Dieting frequently leads to adaptations in the body's metabolism that stimulate overeating and increased appetite to regain lost weight.

Explore the complex relationship between blood glucose and insulin levels, including the effects of different types of foods. This quiz covers key concepts like the Oral Glucose Tolerance Test and diabetes diagnosis criteria as per the 2017 ADA Guidelines. Test your knowledge on the fluctuations of sugar levels in healthy and diabetic individuals.