Causes and Stages of Development of Diabetes Mellitus Type 1 and Type 2

Diabetes Type 1 | Diabetes Type 2 | How does diabetes develop? | Deficiency and Lack of insulin | Receptor insensitivity


In the case when insulin-dependent cells are “closed” to glucose molecules, its excess continues to circulate in the blood (hyperglycemia). Typically, this occurs for two reasons: insulin deficiency due to a decrease or cessation of its formation in the pancreas – type 1 diabetes mellitus, or loss of sensitivity of cell receptors to insulin – type 2 diabetes mellitus.

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Diabetes Type 1

Type 1 diabetes accounts for about 10% of all cases of diabetes. In the vast majority of cases, it is associated with damage to the pancreatic β-cells with their own antibodies (an autoimmune disease in which the body’s own protective cells (antibodies) mistakenly destroy other cells of the body, taking them for foreign). In order for this mechanism to “turn on”, the genes for predisposition to this disease and the trigger factor — one or another “trigger” are necessary. The trigger factor may be a viral infection (rubella, mumps, chickenpox, viral hepatitis, etc.), chemicals (for example, some anticancer drugs). In addition, the risk of developing diabetes is much higher for those with a hereditary predisposition.

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Diabetes Type 2

Type 2 diabetes mellitus is associated with a loss of sensitivity of cells to insulin, while the ability of the pancreas to produce this hormone in the early stages of the disease remains. This form of diabetes is the most common, it occurs in more than 90% of patients. A hereditary predisposition also plays a role in the development of type 2 diabetes mellitus, and in addition, factors such as obesity (especially the abdominal type, that is, with a predominance of fat in the abdomen), age (40 years and older), physical inactivity (while physical loads contribute to the rapid “burning” of glucose and weight loss) and diabetogenic nutrition (excess fatty foods).

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How does diabetes develop?

Despite the fact that with both types of diabetes mellitus, symptoms and complications are associated with the same factor – excessive blood glucose (hyperglycemia), their development occurs in different scenarios.

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Type 1 diabetes mellitus (deficiency and lack of insulin)

  • The disease can develop at any age.
  • From the moment of exposure to the trigger factor (virus, toxic substance, etc.) until the onset of symptoms, months, and more often years, pass.
  • The first signs appear when antibodies destroy 90% or more of the pancreatic β-cells.
  • For the first time, symptoms (and the need to inject insulin) most often appear after the action of a provoking factor, usually stress (trauma, illness). The release of hormones from the adrenal cortex (adrenaline, norepinephrine) leads to a decrease in the sensitivity of cells to insulin, which makes the problem of insulin deficiency obvious.
  • If you eliminate the factor that caused the stress, the sensitivity of the receptors is restored. The remaining β-cells continue to produce insulin in the amount necessary to cover the needs of the body in a state of rest. This period lasts from several weeks to several months and is called the “diabetes honeymoon”. When β-cells are completely destroyed, the formation of the hormone stops: from now on, its deficiency can be compensated for only by insulin injection.

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Type 2 diabetes mellitus (receptor insensitivity)

  • The disease usually develops in people over 40 years old.
  • As a rule, about 7 years elapse from the moment the first problems with insulin sensitivity of cells to the appearance of the first symptoms appear.
  • In order to overcome insulin resistance (insensitivity), pancreatic β-cells have to produce large doses of insulin. Gradually, this leads to the depletion and death of pancreatic cells. The situation is exacerbated by the high sensitivity of pancreatic cells to the toxic effects of glucose itself, which appears in excess in the blood.
  • Over time, β-cells cease to function, which leads to the need for the introduction of insulin (therefore, the use of the term “insulin-independent” in the characterization of type 2 diabetes is considered incorrect).
  • Along with disorders of carbohydrate metabolism, as the disease progresses, a profound disruption of lipid metabolism occurs: the content of “bad” fats (very low density lipoproteins that activate the formation of atherosclerotic plaques) in the blood increases and the concentration of “good” fats (high density lipoproteins that protect blood vessels from atherosclerosis) )
  • In contrast to type 1 diabetes mellitus, which occurs regardless of lifestyle, the development of type 2 diabetes can be significantly slowed by reducing weight, increasing physical activity and adjusting nutrition. Also, an effective method of preventing the disease, slowing the progression, and preventing complications are hypoglycemic agents.