Adenosinergic System Involvement in Ischemic Stroke Patients' Lymphocytes

Adenosine modulates many physiological processes through the interaction with adenosine receptors (ARs) named as A(1), A(2A), A(2B,) and A(3)ARs. During ischemic stroke, adenosine mediates neuroprotective and anti-inflammatory effects through ARs activation. One of the dominant pathways generating extracellular adenosine involves the dephosphorylation of ATP by ecto-nucleotidases CD39 and CD73, which efficiently hydrolyze extracellular ATP to adenosine. The aim of the study is to assess the presence of ARs in lymphocytes from ischemic stroke patients compared to healthy subjects and to analyze changes in CD39 and CD73 expression in CD4(+) and CD8(+) lymphocytes. Saturation binding experiments revealed that A(2A)ARs affinity and density were significantly increased in ischemic stroke patients whilst no differences were found in A(1), A(2B,) and A(3)ARs. These results were also confirmed in reverse transcription (RT)-polymerase chain reaction (PCR) assays where A(2A)AR mRNA levels of ischemic stroke patients were higher than in control subjects. In flow cytometry experiments, the percentage of CD73(+) cells was significantly decreased in lymphocytes and in T-lymphocyte subclasses CD4(+) and CD8(+) obtained from ischemic stroke patients in comparison with healthy individuals. These data corroborate the importance of the adenosinergic system in ischemic stroke and could open the way to more targeted therapeutic approaches and biomarker development for ischemic stroke.