55. Pathobiochemical mechanisms of diabetes mellitus. Types of diabetes. Metabolic disorders, symptoms and complications of type I and II diabetes. Pathobiochemical mechanisms of complications in hyperglycemia – oxidative stress, sorbitol pathway, spontaneous non-enzymatic glycation of proteins – AGE and RAGE, activation of the DAG/PKC cascade.

Diabetes Mellitus: Metabolic Changes in Type I and Type II

Overview of Diabetes Mellitus:

Diabetes mellitus is a group of metabolic disorders characterized by high blood sugar (glucose) levels over a prolonged period. It is mainly classified into two types: Type I and Type II diabetes.

Type I Diabetes (T1D):

Cause: Type I diabetes is an autoimmune disease where the body's immune system attacks and destroys the insulin-producing beta cells in the pancreas.

Metabolic Changes:

• Insulin Deficiency: Leads to decreased glucose uptake by cells.
• Hyperglycemia: High blood sugar levels due to lack of insulin.
• Ketosis: Increased breakdown of fats into ketone bodies, which can lead to diabetic ketoacidosis (DKA), a life-threatening condition.
• Protein Breakdown: Increased protein catabolism leading to muscle wasting and weight loss.

Type II Diabetes (T2D):

Cause: Type II diabetes is primarily associated with insulin resistance (where cells do not respond properly to insulin) and relative insulin deficiency. It is often linked to obesity, sedentary lifestyle, and genetic factors.

Metabolic Changes:

• Insulin Resistance: Cells fail to respond to insulin effectively.
• Hyperinsulinemia: Initially, the pancreas compensates by producing more insulin.
• Hyperglycemia: Eventually, insulin production cannot keep up with demand, leading to high blood sugar levels.
• Dyslipidemia: Abnormal lipid levels due to altered metabolism of fats.