Erythrocytes as model cells for biocompatibility assessment, cytotoxicity screening of xenobiotics and drug delivery.

Erythrocytes (RBCs) represent the main cell component in circulation and recently have become a topic of intensive scientific interest. The relevance of erythrocytes as a model for cytotoxicity screening of xenobiotics is under the spotlight of this review. Erythrocytes constitute a fundamental cellular model to study potential interactions with blood components of manifold novel polymer or biomaterials. Morphological changes, subsequent disruption of RBC membrane integrity, and hemolysis could be used to determine the cytotoxicity of various compounds. Erythrocytes undergo a programmed death (eryptosis) which could serve as a good model for evaluating certain mechanisms which correspond to apoptosis taking place in nucleated cells. Importantly, erythrocytes can be successfully used as a valuable cellular model in examination of oxidative stress generated by certain diseases or multiple xenobiotics since red cells are subjected to permanent oxidative stress. Additionally, the antioxidant capacity of erythrocytes, and the activity of anti-oxidative enzymes could reflect reactive oxygen species (ROS) generating properties of various substances and allow to determine their effects on tissues. The last part of this review presents the latest findings on the possible application of RBCs as drug delivery systems (DDS). In conclusion, all these findings make erythrocytes highly valuable cells for in vitro biocompatibility assessment, cytotoxicity screening of a wide variety of substances as well as drug delivery.

Assessment of the relationship between platelet reactivity, vascular risk factors and gender in cerebral ischaemia patients.

AIM: Excessive activation and platelet aggregation play important roles in the aetiopathogenesis of cerebral ischaemia. The aim of this study was to assess the relationship between platelet reactivity, gender and vascular risk factors in cerebral ischaemia patients. CLINICAL RATIONALE FOR THE STUDY: The research is useful because we found high risk groups of inefficient aspirin treatment in cerebral ischaemia patients. MATERIAL AND METHODS: The study involved 101 patients, including 69 patients with ischaemic stroke and 32 patients with transient ischaemic attack. The assessment of platelet reactivity was made within 24 hours of the disease onset using two aggregometric methods: impedance and optical. RESULTS: Resistance to acetylsalicylic acid among people with cerebral ischaemia was estimated at 30.69% using impedance aggregometry and 9.2% using optical aggregometry. There were no differences in platelet reactivity or ASA resistance between the groups of patients with stroke and TIA in either method. In the whole group of patients (p = 0.04), and in the group of patients with stroke (p = 0.0143), higher reactivity of platelets was observed by impedance aggregometry in men than in women. In the whole group of patients (p = 0.0229), and in the subgroup with stroke (p = 0.0123), it was shown that aspirin resistance is significantly more common in the subgroup of men than in women. In patients suffering from nicotine addiction, significantly higher platelet reactivity was found in the whole group of patients (p = 0.004), as well as in the subgroup of patients with stroke (p = 0.0135). CONCLUSIONS: There are no differences between platelet reactivity and the incidence of aspirin resistance in patients with stroke and TIA. Male gender and smoking are associated with greater reactivity of platelets and more frequent occurrence of acetylsalicylic acid resistance in patients with cerebral ischaemia. CLINICAL IMPLICATIONS: Dual antiplatelet therapy or clopidogrel treatment should be considered in smoking males with cerebral ischaemia due to the high risk of aspirin inefficiency.