Heart of a Diabetic
Bělobrádková J.1, Filipenský B.2
1Diabetologické centrum, Interní gastroenterologická klinika Lékařské fakulty MU a FN Brno, pracoviště Bohunice, přednosta prof. MUDr. Petr Dítě, DrSc. 2Interní oddělení Nemocnice Milosrdných bratří, Brno, přednosta prim. MUDr. Bohumil Filipenský |
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Summary:
Macrovascular complications in diabetics create a high risk for cardiovascular disease (CVD).
Generally, the main risk factors for CVD include age, men´s sex, elevated LDL-cholesterol and
reduced HDL-cholesterol, elevated fibrinogen, hypertension, smoking, and diabetes mellitus. Clinical
manifestation of coronary disease is determined by number, area, and severity of coronary
stenoses, myocardial function, and presence of induced ischemia. Routine pharmacological treatment
of ISHD concentrates on risk factors and hasn´t been yet focused on changes in energy
metabolism during ischemic situation which are important factors contributing to ischemic damage.
Substances able to optimise energy metabolism of heart muscle offer a very tempting way
both for ISHD treatment and for treatment of following cardiovascular complications. Optimal
use of energy source in heart muscle can favour heart activity so that comparable amount of
contractile work requires less oxygen. The most beneficial way of getting energy for myocardium
while low consumption of oxygen is oxidation of glucose. Because of a large amount of free fatty
acids (FFAs) in diabetics a more demanding way of oxidation takes place in them, the oxidation of
FFAs. Therefore myocardium of a diabetic needs under normal perfusion conditions more oxygen
to provide energy. Besides increase in demand of oxygen, FFAs separate glycolysis from glucose
oxidation and increase undesirable production of lactate and protons. An ischemic myocardium
of a diabetic has primarily bigger demand of oxygen then myocardium of a non-diabetic. Development
of cell ischemia, with all the known consequences in forms of lactate acidosis, calcium
overload, and depletion of ATP, leads to considerable contractile disorder. Unfavourable position
of metabolic activities in myocardium of diabetics and faster and more serious progression of
atherosclerosis result in a big risk of CVD in diabetics. Incidence of coronary events in diabetics
without history of ISHD is as big as in non-diabetics with history of coronary events.
Key words:
Diabetes mellitus – Macrovascular complications – Free fatty acids - Ischemic heart
disease
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