Untreated diabetes mellitus may lead to blindness and kidney failure because the basement membrane of small blood vessels in these organs thickens due to increased production of collagen and laminin.

My questions : why are these organs most susceptible ? Why will collagen and laminin production increase in diabetes mellitus ?


The endothelial cells in small blood vessels take in more glucose (as glucose levels in blood are high due to diabetes.) Thus they form surface glycoproteins which causes the basement membrane to become thicker yet less strong. This leads to blood and protein leakage from the blood stream in other tissues in the space between cells. Blood leakage alters cellular blood supply for all cells.

Less blood means less oxygen and less nutrients. As you probably know nervous tissue gets damaged fastest without oxygen thus explaining diabetic neuropathy. Also retina and kidney contain cells that get easily damaged when there is not enough blood.

Probably the worst complication is neuropathy, because the person suffering from it may suffer a heart attack (caused by the accelerated process of atherosclerosis in diabetes) and feel less pain (http://medlineplus.gov).

Collagen and laminin poduction increases as a result of the fibrosis process that takes place when a tissue gets less nutrients than it needs.

Diabetes affects all blood vessels, even the larger ones. See macroangiopaty.

From http://en.wikipedia.org/wiki/Microangiopathy

  • 3
    $\begingroup$ Plasma glucose can react (non-enzymatically) with the side chains of some amino acids to form Advanced Glycation Endproducts (AGEs). AGEs are pro-inflammtory and can cause signalling via specific receptors for AGE - the RAGE family. This, in large part can drive OP's thickening. Do you have a reference for reduced pain in heart attacks ? $\endgroup$
    – PlaysDice
    Apr 22 '14 at 15:04
  • $\begingroup$ @playsdice Could you please elaborate it in the form of an answer ? $\endgroup$
    – biogirl
    Apr 22 '14 at 16:32
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    $\begingroup$ @biogirl - comments were to suggest tweaks to this answer. You should also search 'complications of diabetes'. Its a fascinating field. $\endgroup$
    – PlaysDice
    Apr 22 '14 at 17:27
  • $\begingroup$ @cornelius could u explain ur first statement ? increase insulin level leads to increase in uptake of glucose in cells. Instead of saying that cells take inglucose EVEN THOUGH insulin level is high u should say that because insulin level is high. $\endgroup$
    – biogirl
    Apr 25 '14 at 14:37
  • 1
    $\begingroup$ @biogirl insulin has nothing to do with the amount of glucose that endothelial cells take in. They simply take in glucose based on its concentration in blood. $\endgroup$
    – Cornelius
    Apr 25 '14 at 14:52

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