Trifluoperazine-Induced Suicidal Erythrocyte Death and S-Nitrosylation Inhibition, Reversed by the Nitric Oxide Donor Sodium Nitroprusside.

BACKGROUND AND PURPOSE: The high potency antipsychotic drug trifluoperazine (10-[3-(4-methyl-1-piperazinyl)-propyl]-2-(trifluoromethyl)-(10)H-phenothiazine dihydrochloride; TFP) may either counteract or promote suicidal cell death or apoptosis. Similar to apoptosis, erythrocytes may enter eryptosis, characterized by phosphatidylserine exposure at the cell surface and cell shrinkage. Eryptosis can be stimulated by an increase in cytoplasmic Ca2+ concentration ([Ca2+]i) and inhibited by nitric oxide (NO). We explored whether TFP treatment of erythrocytes induces phosphatidylserine exposure, cell shrinkage, and calcium influx, whether it impairs S-nitrosylation and whether these effects are inhibited by NO. METHODS: Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, and protein nitrosylation from fluorescence switch of the Bodipy-TMR/Sypro Ruby signal. RESULTS: Exposure of human erythrocytes to TFP significantly enhanced the percentage of annexin-V-binding cells, raised [Ca2+]i, and decreased S-nitrosylation. The effect of TFP on annexin-V-binding was not affected by removal of extracellular Ca2+ alone, but was significantly inhibited by pre-treatment with sodium nitroprusside (SNP), an effect significantly augmented by additional removal of extracellular Ca2+. A 3 hours treatment with 0.1 µM Ca2+ ionophore ionomycin triggered annexin-V-binding and cell shrinkage, effects fully reversed by removal of extracellular Ca2+. CONCLUSIONS: TFP induces eryptosis and decreases protein S-nitrosylation, effects blunted by nitroprusside. The effect of nitroprusside is attenuated in the presence of extracellular Ca2+.

How Satisfied Are Patients with Arthroscopic Bankart Repair? A 2-Year Follow-up on Quality-of-Life Outcome.

PURPOSE: To report general life and health satisfaction after arthroscopic Bankart repair in patients with post-traumatic recurrent anterior glenohumeral instability and to investigate postoperative time lost to return to work at 2-year follow-up. METHODS: Between 2011 and 2013 patients treated with arthroscopic Bankart repair in the beach chair position for acute shoulder instability were included in this study. Questions on Life Satisfaction Modules (FLZM) and the Short Form 12 (SF-12) were used as quality-of-life outcome scales. Oxford Instability Score (OIS), Quick Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH), and self-reported American Shoulder and Elbow Surgeons (ASES) shoulder index were used as functional outcome scales. Return to work (months) was monitored and analyzed depending on physical workload. Data were assessed the day before surgery and prospectively monitored until 24 months postoperatively. Quality-of-life outcome was correlated with functional shoulder outcome and compared with normative age-adjusted data. Paired t-test, Wilcoxon test, Mann-Whitney U-Test, and Spearman's correlation coefficient were used for statistical analysis. RESULTS: Fifty-three patients were prospectively included. The mean age at surgery was 29.4 years. Satisfaction with general life and satisfaction with health (FLZM) as well as physical component scale (SF-12) improved significantly to values above normative data within 6 to 12 months after surgery (each P < .001). OIS, QuickDASH, and ASES improved significantly from baseline until 24 months after surgery (each P < .001). For ASES, improvement above minimal clinically important difference was shown. There was a positive correlation between quality of life and functional outcome scores (P < .05; rho, 0.3-0.4). Mean time to return to work was 2 months (range, 0-10; standard deviation, 1.9), with significantly longer time intervals observed in patients with heavy physical workload (3.1 months; range, 0 to 10; standard deviation, 2.4; P = .002). CONCLUSIONS: Following arthroscopic Bankart repair, quality of life was impaired during early course after surgery and increased significantly above preoperative levels within 6 to 12 months after the procedure. A steady state of excellent quality-of-life and functional outcomes was noted after 12 months of follow-up. Quality-of-life outcome scales correlated significantly with the functional outcome. Heavy physical workload must be considered as a risk factor for prolonged time lost to return to work. LEVEL OF EVIDENCE: Level III, prospective noncomparative therapeutic case series.

Ritonavir-Induced Suicidal Death of Human Erythrocytes.

The antiviral drug ritonavir has been shown to trigger suicidal death or apoptosis of tumour cells and has thus been considered for the treatment of malignancy. In analogy to apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include Ca(2+) entry with increase in cytosolic Ca(2+) activity ([Ca(2+) ]i ), oxidative stress and ceramide. The present study explored whether and how ritonavir induces eryptosis. To this end, flow cytometry was employed to estimate cell volume from forward scatter, phosphatidylserine exposure at the cell surface from Annexin-V binding, [Ca(2+) ]i from Fluo3 fluorescence, abundance of reactive oxygen species (ROS) from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence and ceramide abundance utilizing specific antibodies. As a result, a 48-hr exposure of human erythrocytes to ritonavir significantly increased the percentage of Annexin-V-binding cells (≥5 µg/ml), significantly decreased forward scatter (≥5 µg/ml), significantly increased Fluo3 fluorescence (20 µg/ml), slightly, but significantly increased DCFDA fluorescence (20 µg/ml) and slightly, but significantly increased ceramide abundance (20 µg/ml). The effect of ritonavir on Annexin-V binding was significantly blunted, but not fully abolished by the removal of extracellular Ca(2+) . In conclusion, ritonavir triggers erythrocyte shrinkage and phosphatidylserine translocation at the erythrocyte cell membrane, an effect in part due to the stimulation of Ca(2+) entry, oxidative stress and ceramide.

Enhanced Eryptosis Following Exposure to Lopinavir.

BACKGROUND/AIMS: The protease inhibitor lopinavir, used for the treatment of HIV infections, triggers suicidal death or apoptosis of nucleated cells. Side effects of lopinavir include anemia, which could in theory result from stimulation of suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and by phospholipid scrambling of the cell membrane leading to phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include oxidative stress, increase of cytosolic Ca2+ activity ([Ca2+]i), and ceramide. The present study explored, whether lopinavir induces eryptosis. METHODS: Flow cytometry was employed to estimate phosphatidylserine exposure at the cell surface from annexin-V-binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, reactive oxygen species (ROS) abundance from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence, reduced glutathione (GSH) from mercury orange fluorescence and ceramide abundance utilizing labelled specific antibodies. Hemolysis was estimated from haemoglobin concentration of the supernatant. RESULTS: A 48 hours exposure of human erythrocytes to lopinavir significantly increased the percentage of annexin-V-binding cells (≥ 10 µg/ml), significantly decreased forward scatter (≥15 µg/ml), significantly increased hemolysis (≥ 15 µg/ml), significantly increased Fluo3-fluorescence (20 µg/ml), and significantly increased DCFDA fluorescence (20 µg/ml) but did not significantly modify ceramide abundance. The effect of lopinavir on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca2+. CONCLUSION: Lopinavir treatment of erythrocytes from healthy volunteers is followed by cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part due to stimulation of ROS formation and Ca2+ entry.

Efavirenz Induced Suicidal Death of Human Erythrocytes.

BACKGROUND/AIMS: The reverse transcriptase inhibitor efavirenz utilized for the treatment of human immunodeficiency virus (HIV)-1 infection, triggers suicidal cell death or apoptosis, an effect in part due to interference with mitochondrial potential. Side effects of efavirenz include anemia. Causes of anemia include accelerated clearance of circulating erythrocytes. Even though lacking mitochondria, erythrocytes may enter suicidal erythrocyte death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include Ca2+ entry and increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress, ceramide, as well as activation of p38 kinase, casein kinase 1α and/or cyclooxygenase. The present study explored, whether and how efavirenz induces eryptosis. METHODS: Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing selective antibodies. RESULTS: A 48 hours exposure of human erythrocytes to efavirenz (≥ 2 µg/ml) significantly increased the percentage of annexin-V-binding cells, significantly decreased forward scatter (2 µg/ml), significantly increased Fluo3-fluorescence (≥ 2 µg/ml), but did not significantly modify DCFDA fluorescence or ceramide abundance. The effect of efavirenz on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca2+. The effect of efavirenz on annexin-V-binding was further significantly blunted by p38 kinase inhibitor SB203580 (2 µM) and casein kinase 1α inhibitor D4476 (10 µM), but not by cyclooxygenase inhibitor aspirin (50 µM). CONCLUSIONS: Efavirenz triggers cell shrinkage and phosphatidylserine translocation to the erythrocyte surface, an effect in part due to stimulation of Ca2+ entry as well as activation of p38 kinase and casein kinase 1α.

Saquinavir Induced Suicidal Death of Human Erythrocytes.

BACKGROUND/AIMS: The antiretroviral protease inhibitor saquinavir is used for the treatment of HIV infections. Effects of saquinavir include induction of apoptosis, the suicidal death of nucleated cells. Saquinavir treatment may further lead to anemia. In theory, anemia could result from accelerated erythrocyte loss by enhanced suicidal erythrocyte death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include Ca2+ entry with increase of cytosolic Ca2+ activity ([Ca2+]i), oxidative stress with increase of reactive oxygen species (ROS) and ceramide. The present study explored, whether and how saquinavir induces eryptosis. METHODS: To this end, flow cytometry was employed to estimate erythrocyte volume from forward scatter, phosphatidylserine exposure at the cell surface from annexin-V-binding, [Ca2+]i from Fluo3-fluorescence, ROS abundance from DCFDA fluorescence and ceramide abundance utilizing specific antibodies. RESULTS: A 48 hours exposure of human erythrocytes to saquinavir significantly decreased forward scatter (≥ 5 µg/ml), significantly increased the percentage of annexin-V-binding cells (≥ 10 µg/ml), significantly increased Fluo3-fluorescence (15 µg/ml), significantly increased DCFDA fluorescence (15 µg/ml), but did not significantly modify ceramide abundance. The effect of saquinavir on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca2+. CONCLUSIONS: Saquinavir triggers cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane, an effect in part due to stimulation of ROS formation and Ca2+ entry.

Induction of suicidal erythrocyte death by nelfinavir.

The HIV protease inhibitor, nelfinavir, primarily used for the treatment of HIV infections, has later been shown to be effective in various infectious diseases including malaria. Nelfinavir may trigger mitochondria-independent cell death. Erythrocytes may undergo eryptosis, a mitochondria-independent suicidal cell death characterized by cell shrinkage and phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include oxidative stress and increase of cytosolic Ca2+-activity ([Ca2+]i). During malaria, accelerated death of infected erythrocytes may decrease parasitemia and thus favorably influence the clinical course of the disease. In the present study, phosphatidylserine abundance at the cell surface was estimated from annexin V binding, cell volume from forward scatter, reactive oxidant species (ROS) from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence, and [Ca2+]i from Fluo3-fluorescence. A 48 h treatment of human erythrocytes with nelfinavir significantly increased the percentage of annexin-V-binding cells (≥5µg/mL), significantly decreased forward scatter (≥2.5µg/mL), significantly increased ROS abundance (10 µg/mL), and significantly increased [Ca2+]i (≥5 µg/mL). The up-regulation of annexin-V-binding following nelfinavir treatment was significantly blunted, but not abolished by either addition of the antioxidant N-acetylcysteine (1 mM) or removal of extracellular Ca2+. In conclusion, exposure of erythrocytes to nelfinavir induces oxidative stress and Ca2+ entry, thus leading to suicidal erythrocyte death characterized by erythrocyte shrinkage and erythrocyte membrane scrambling.