Week 10

Question 1

Diabetes?

Answer 1

Diabetes is a disorder of carbohydrate metabolism, characterized by high blood sugar (hyperglycemia) and sugar in urine (glycosuria). It occurs when insulin production or use is inadequate, leading to tissue damage.

It’s classified into:
Type 1 (IDDM): Insulin-dependent
Type 2 (NIDDM): Non-insulin-dependent

Prevalence increases with age, and heredity is a factor in both types. Impaired Glucose Tolerance (IGT) is a pre-diabetic condition.

Question 2

What methods are available to measure insulin
sensitivity/resistance? and what is best?

Answer 2

Hyperinsulinaemic euglycaemic clamp - best

Insulin Tolerance Test

Intravenous Glucose Tolerance Test

Homeostatic Model Assessment

Quantitative insulin sensitivity check index

Oral Glucose Tolerance Test

Question 3

Principle of Hyperinsulinaemic Euglycaemic clamp?

Answer 3

Process:
Continuous insulin infusion raises blood insulin levels.

Glucose infusion maintains stable blood sugar (euglycaemia).

Purpose: The amount of glucose needed to maintain normal sugar levels indicates insulin sensitivity.

Key Insight:
High insulin levels suppress liver glucose production.
Infused glucose matches the body’s glucose usage, reflecting how sensitive the body is to insulin.

Question 4

Principle of Oral Glucose Tolerance Test?

Answer 4

Measures how the body handles glucose. After fasting, the patient drinks a glucose solution, and blood glucose levels are tested at intervals (usually 30 minutes, 1 hour, and 2 hours). The body’s ability to clear glucose from the blood helps assess insulin sensitivity and can indicate conditions like prediabetes or diabetes

Question 5

Homeostatic Model Assessment (HOMA)? +/– ?

Answer 5

Purpose: Estimates insulin resistance (HOMA-IR) and beta-cell function (HOMA-B) using fasting blood glucose and insulin levels.

HOMA-IR: Calculated to assess insulin resistance from fasting insulin and glucose levels.

HOMA-B: Measures beta-cell function, indicating how well the pancreas produces insulin.

Advantages: Simple, non-invasive method for estimating insulin resistance and beta-cell function.

Limitations: Provides an estimate rather than a direct measurement.

Question 6

Positive Effects of training on glycaemic control?

Answer 6

Muscle Hypertrophy: Increases insulin target tissue.

Capillary Density: Enhances glucose delivery to muscles.

Insulin Signaling: Improves due to reduced adiposity and altered adipocytokines.

Lower Intramuscular Fat: Decreases inhibition of insulin action.

AMPK Activation: Boosts mitochondrial biogenesis, fat oxidation, and CPT1 activity.

TBC1D4: Increased levels and phosphorylation enhance insulin sensitivity.

GLUT-4 Transporter: Upregulated expression improves glucose uptake.

Enzymes: Enhanced glucose storage and oxidation enzymes support better control.

Question 7

How does insulin resistance contribute to Metabolic Syndrome and cardiovascular risk?

Answer 7

Central Factor: Insulin resistance is key in Metabolic Syndrome, increasing cardiovascular disease (CVD) risk.

Abdominal Obesity: Encourages fat storage in the abdomen, raising CVD risk.

High Blood Pressure: Causes sodium retention, increased sympathetic activity, and vascular dysfunction, leading to hypertension.

Dyslipidemia: Results in elevated triglycerides and low HDL cholesterol, linked to atherosclerosis.

Elevated Fasting Glucose: Impairs glucose clearance, leading to high blood sugar and vascular damage.

These factors create a pro-inflammatory, pro-thrombotic environment, heightening CVD risk.