The Role of Adenosine and Its Degradation Enzymes – Adenosinedeaminase and Adenosinekinase in Pathogenesis of Vasovagal Syncope

Published:September 05, 2022DOI:


      • Adenosinergic system may play a role in the pathogenesis of vasovagal syncope.
      • Patients with tilt-induced VVS have higher serum adenosine than negative controls.
      • Adenosine is probably implicated predominantly in vasodepressoric type of VVS.
      • Patients with tilt-induced VVS have lower activity of adenosinedeaminase than controls.



      Adenosine is mediator regulating physiological and pathological processes in organism. It probably plays a role in pathogenesis of vasovagal syncopes (VVS), too. Adenosine, its receptors and degradation enzymes– adenosinedeaminase (ADA) and adenosinekinase (ADK), are called the adenosinergic system.


      We aimed to evaluate serum levels of adenosine, ADA and ADK in patients with tilt-induced VVS and compare them to tlit-negative controls. Secondary aim was to compare the levels between the types of VVS and correlate them with hemodynamic parameters.

      Subjects and methods

      Altogether 132 individuals were involved in this study (age 39,88±15,64 years, 51 males). All patients underwent head up tilt test (HUTT) in differential diagnosis of syncope. Blood sampling was performed before and after HUTT. Baseline and stimulated serum levels of adenosine, ADA and ADK were evaluated by ELISA method.


      HUTT was positive in 91 patients (HUTT+), 41 individuals were negative (HUTT-). HUTT+ patients had higher baseline and stimulated adenosine levels, when compared to HUTT- population. The rise in adenosine was higher in HUTT+ group. On the other hand, the increase of ADA was significantly higher in HUTT- subjects. Among HUTT+ group, the highest adenosine was found during vasodepressoric VVS.


      Adenosinergic system may play role in pathogenesis of VVS. Patients with VVS have higher adenosine levels, that may be caused by attenuated degradation. Adenosine seems to be involved predominantly in vasodepressoric type of VVS. Further research evaluating complex function of adenosinergic system in these patients is needed.


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