Bogdan Jakiela

The additive antiplatelet action of clopidogrel in patients with coronary artery disease treated with aspirin

We searched for additional anti-platelet effects of clopidogrel in coronary artery disease (CAD) patients treated with aspirin. Response to clopidogrel was also stratified according to aspirin resistance. Out of 76 screened aspirin-treated CAD male patients, five were aspirin-resistant based on arachidonic acid (AA) and ADP aggregometry. These five patients and 15 aspirin-sensitive patients entered the proper study. Platelet function was assessed at baseline and after one week of additional clopidogrel treatment using aggregometry, flow cytometry (ADP, TRAP-6) and platelet reactivity index (PRI) based on VASP (vasodilatorstimulated phosphoprotein) expression. We evaluated the same markers in 15 healthy men after aspirin treatment. In healthy subjects aspirin did not affect resting or ADP-induced activated GPIIb/IIIa and P-selectin expression. The P-selectin expression on ADP-activated platelets was increased (p < 0.01) in aspirin treated ASA-resistant CAD patients as compared to ASA-sensitive group or aspirin-treated healthy subjects. Clopidogrel significantly decreased ADP and AA-induced platelet aggregation and overcame aspirin resistance in four of five patients. Expression of ADP-induced activation markers was significantly lowered after clopidogrel in all patients. Out of 20 patients, five did not respond to clopidogrel (<10% inhibition of ADP aggregation), and this group showed no change in expression of ADP-induced activation markers after clopidogrel. Clopidogrel treatment significantly reduced PRI only in the clopidogrel-sensitive group. In conclusion, the addition of clopidogrel to aspirin provides greater inhibition of platelets and can overcome aspirin resistance. Flow cytometric analysis of platelets is useful for monitoring of clopidogrel therapy.

Imbalance between Th17 and regulatory T-cells in systemic lupus erythematosus.

Impaired function of regulatory T-cells (Treg) leads to a failure in immune tolerance and triggers autoimmunity. We analyzed whether the deficiency in Treg in systemic lupus erythematosus (SLE) is accompanied by an increase in effector T-cell responses. We studied the frequencies of IL-17A (Th17) and IFNg (Th1) producing CD4(+) T-cells by flow cytometric detection of intracellular cytokines in PMA/ionomycin stimulated blood lymphocytes from seven patients with active SLE, eight with SLE in remission, and 11 healthy controls. Circulating Treg were evaluated as CD4(+)CD25(+) lymphocytes expressing FoxP3. There was no difference in the percentage of Treg cells between the groups, but their absolute counts were decreased in active SLE (5 [1-7] cells/μL) compared to inactive SLE (11 [6-15]; p = 0.05) and healthy controls (16 [10-20]; p 〈 0.01). Both the frequency and numbers of Th1 cells were decreased in SLE compared to controls. No difference was observed in the number of Th17 cells, which resulted in a decreased Th1/Th17 ratio. In parallel, a higher Treg/Th17 ratio in healthy controls (2.2 [1.8-3.6]) compared to active SLE (1.1 [1.0-2.1]; p 〈 0.05) was observed. There was a correlation between the number of Treg cells and disease activity status (SLEDAI, r = -0.59). SLE patients in the active phase of the disease are characterized by a deficiency in Treg cells and decreased Treg/Th17 ratio. This suggests that the imbalance between major T-cells subsets might be responsible for an increased proinflammatory response in the exacerbation of SLE.

Regulation of bronchial epithelial barrier integrity by type 2 cytokines and histone deacetylases in asthmatic patients

Background: Tight junctions (TJs) form a barrier on the apical side of neighboring epithelial cells in the bronchial mucosa. Changes in their integrity might play a role in asthma pathogenesis by enabling the paracellular influx of allergens, toxins, and microbes to the submucosal tissue. Objective: The regulation of bronchial epithelial TJs by TH2 cells and their cytokines and their involvement in epigenetic regulation of barrier function were investigated. Methods: The expression, regulation, and function of TJs were determined in air‐liquid interface (ALI) cultures of control and asthmatic primary human bronchial epithelial cells (HBECs) by means of analysis of transepithelial electrical resistance, paracellular flux, mRNA expression, Western blotting, and immunofluorescence staining. Results: HBECs from asthmatic patients showed a significantly low TJ integrity in ALI cultures compared with HBECs from healthy subjects. TH2 cell numbers and levels of their cytokines, IL‐4 and IL‐13, decreased barrier integrity in ALI cultures of HBECs from control subjects but not in HBECs from asthmatic patients. They induced a physical separation of the TJs of adjacent cells in immunofluorescence staining of the TJ molecules occludin and zonula occludens‐1. We observed that expression of histone deacetylases (HDACs) 1 and 9, and Silent information regulator genes (sirtuins [SIRTs]) 6 and 7 were significantly high in HBECs from asthmatic patients. IL‐4 and IL‐13 significantly increased the expression of HDACs and SIRTs. The role of HDAC activation on epithelial barrier leakiness was confirmed by HDAC inhibition, which improved barrier integrity through increased synthesis of TJ molecules in epithelium from asthmatic patients to the level seen in HBECs from control subjects. Conclusion: Our data demonstrate that barrier leakiness in asthmatic patients is induced by TH2 cells, IL‐4, and IL‐13 and HDAC activity. The inhibition of endogenous HDAC activity reconstitutes defective barrier by increasing TJ expression.

Cutting Edge Issues in the Churg–Strauss Syndrome

Churg–Strauss syndrome (CSS) is a rare systemic small-vessel vasculitis that develops in the background of bronchial asthma, which is characterized by eosinophilia and eosinophilic infiltration of various tissues. It belongs to the group of antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides. The triggering factors and pathogenesis of CSS are still unknown. The possible role of eotaxin-3 and CCR4-related chemokines in selective recruitment of eosinophils to the target tissues in CSS has been recently suggested, but the role of eosinophilic inflammation in the development of vasculitic lesions is not completely understood. From the clinical view, two distinct phenotypes of the disease are slowly emerging depending on the ANCA-positivity status. Glucocorticoids are still the mainstay of treatment; however, data are accumulating regarding the beneficial role of novel immunosuppressants and biologic compounds, especially in patients with poorer prognosis.

Anti-thrombotic action of clopidogrel and PlA1/A2 polymorphism of ß3 integrin in patients with coronary artery disease not being treated with aspirin

Individual variability in response to clopidogrel is known but its mechanism is poorly understood. We examined the relationship between glycoprotein IIIa polymorphism P1(A1/A2) and anti-thrombotic actions of clopidogrel. Clopidogrel (75 mg/d; 2 weeks) was administered to 48 normolipemic patients with coronary artery disease. Bleeding time, thrombin generation at the site of microvascular injury, platelet function under high shear, using PFA-100 with ADP cartridge, and platelet surface activation markers (P-selectin and fibrinogen binding sites on GPIIb/IIIa complex detected by PAC-1 antibody), were studied both before and after clopidogrel treatment. Both unstimulated and low-dose (0.02 microM and 1 microM) in vitro ADP-stimulated platelets were examined. GP IIIa polymorphism was assessed by polymerase chain reaction and restriction fragment length polymorphism analysis. We identified 32 P1(A1/A1) homozygotes, 15 P1(A1/A2 heterozygotes and one P1(A2/A2) homozygote. Clopidogrel significantly prolonged bleeding time in all subjects, but this effect was greater in P1(A2 carriers (p < 0.01). Furthermore, clopidogrel only depressed thrombin generation at the site of microvascular injury (p < 0.01) in P1(A2) patients and prolonged closure time measured in vitro by PFA-100 (p < 0.05). At baseline spontaneous expression of PAC-1 and P-selectin was higher in P1(A2) subjects as compared to P1(A1) homozygotes (p < 0.05 for both antigens). Clopidogrel lowered the expression of both markers affecting more P1(A2) carriers, so that the difference in binding PAC-1 antibody between platelets from P1(A1) and P1(A2) carriers disappeared, while the difference in P-selectin expression slightly diminished. Anti-thrombotic effects of clopidogrel are more pronounced in CAD patients carrying the P1(A2) allele than in P1(A1) homozygotes.

Th2-Type Cytokine–Induced Mucus Metaplasia Decreases Susceptibility of Human Bronchial Epithelium to Rhinovirus Infection

Human rhinoviruses (RVs) are a major cause of exacerbations in asthma and other chronic airway diseases. A characteristic feature of asthmatic epithelium is goblet cell metaplasia and mucus hypersecretion. Bronchial epithelium is also an important source of lipid mediators, including pro- and antiinflammatory eicosanoids. By using air-liquid interface cultures of airway epithelium from patients with asthma and nonasthmatic control subjects, we compared RV16 replication-induced changes in mRNA expression of asthma candidate genes and eicosanoid production in the epithelium with or without IL-13-induced mucus metaplasia. Mucus metaplastic epithelium was characterized by a 20-fold less effective replication of RV16 and blunted changes in gene expression; this effect was seen to the same extent in patients with asthma and control subjects. We identified ciliary cells as the main target for RV16 by immunofluorescence imaging and demonstrated that the numbers of ciliary cells decreased in RV16-infected epithelium. RV16 infection of mucociliary epithelium resulted in overexpression of genes associated with bronchial remodeling (e.g., MUC5AC, FGF2, and HBEGF), induction of cyclooxygenase-2, and increased secretion of prostaglandins. These responses were similar in both studied groups. These data indicate that structural changes associated with mucus metaplasia renders airway epithelium less susceptible to RV infection. Thus, exacerbations of the lung disease caused by RV may result from severe impairment in mucociliary clearance or activation of immune defense rather than from preferential infection of mucus metaplastic epithelium. Repeated rhinoviral infections of compromised epithelium may contribute to the remodeling of the airways.

Intrinsic pathway of apoptosis in peripheral blood eosinophils of Churg–Strauss syndrome

OBJECTIVES Churg-Strauss syndrome (CSS) is a rare necrotizing vasculitis associated with asthma, blood and tissue eosinophilia and granuloma formation. We wondered whether eosinophil accumulation in CSS results from the defect of intrinsic apoptosis pathway in blood eosinophils, leading to their prolonged survival. METHODS We analysed immunophenotype (flow cytometry), expression of apoptosis-related genes (real-time PCR) and spontaneous apoptosis in blood eosinophils isolated from nine patients in exacerbation (active CSS), seven patients in remission (inactive CSS) and 14 matched healthy subjects. Serum IL-5 levels were also measured. RESULTS In active CSS, blood eosinophils were characterized by small (<2-fold) decrease in expression of a few genes, primarily proapoptotic (e.g. BCL2L13, CASP2, CARD4) or involved in regulation of NF-kappaB (IKBKB, REL), but they did not differ in the rate of spontaneous apoptosis, when compared with other groups. Only selected genes were positively (BNIPL, PYCARD, CASP8, CRADD, BCAP31), or negatively (IKBKE) correlated with disease activity. In active CSS, eosinophils expressed activation markers (CD69, CD25), especially in subjects with most severe disease and elevated serum IL-5. CONCLUSIONS High susceptibility of peripheral blood eosinophils to spontaneous apoptosis in vitro, and minor changes in expression of apoptotic-related genes in transcriptome analysis, do not support the hypothesis on intrinsic defect in apoptosis, as the cause of eosinophil accumulation in CSS.

Lithium Attenuates TGF-β1-Induced Fibroblasts to Myofibroblasts Transition in Bronchial Fibroblasts Derived from Asthmatic Patients

Bronchial asthma is a chronic disorder accompanied by phenotypic transitions of bronchial epithelial cells, smooth muscle cells, and fibroblasts. Human bronchial fibroblasts (HBFs) derived from patients with diagnosed asthma display predestination towards TGF-β-induced phenotypic switches. Since the interference between TGF-β and GSK-3β signaling contributes to pathophysiology of chronic lung diseases, we investigated the effect of lithium, a nonspecific GSK-3β inhibitor, on TGF-β 1-induced fibroblast to myofibroblast transition (FMT) in HBF and found that the inhibition of GSK-3β attenuates TGF-β 1-induced FMT in HBF populations derived from asthmatic but not healthy donors. Cytoplasmically sequestrated β-catenin, abundant in TGF-β 1/LiCl-stimulated asthmatic HBFs, most likely interacts with and inhibits the nuclear accumulation and signal transduction of Smad proteins. These data indicate that the specific cellular context determines FMT-related responses of HBFs to factors interfering with the TGF-β signaling pathway. They may also provide a mechanistic explanation for epidemiological data revealing coincidental remission of asthmatic syndromes and their recurrence upon the discontinuation of lithium therapy in certain psychiatric diseases.

Elevated cerebrospinal fluid interleukin-17A and interferon-γ levels in early asymptomatic neurosyphilis.

Background The mechanisms underlying the process of Treponema pallidum clearance from the central nervous system have not yet been established. Considering that neurosyphilis is associated with mild cerebrospinal fluid (CSF) pleocytosis with a lymphocytic predominance, it has been suggested that cells involved in the adaptive immune response may play a role in this process. In the current study, we assessed the cytokine production profile of T-helper cells in the serum and CSF of patients with early syphilis, with and without CSF abnormalities. Methods Cerebrospinal fluid and blood samples were collected from 33 patients with secondary and early latent syphilis. Five patients (15%) had a reactive CSF Venereal Disease Research Laboratory test without any accompanying neurological symptoms. According to the Centers of Disease Control and Prevention classification, they were diagnosed with asymptomatic neurosyphilis. Serum and CSF levels of interferon-&ggr; (IFN-&ggr;; Th1-type cytokine), interleukin-4 (IL-4; Th2-type cytokine), and interleukin-17A (IL-17A; Th17-type cytokine) were determined by enzyme-linked immunosorbent assay. Results Patients with asymptomatic neurosyphilis had significantly higher levels of IL-17A (8-fold) and IFN-&ggr; (7.8-fold) in the CSF compared with patients in the no-neurosyphilis group. Six individuals had CSF pleocytosis but a negative CSF Venereal Disease Research Laboratory test result (presumptive neurosyphilis group). In this group, CSF IFN-&ggr; and CSF IL-17A levels were also significantly elevated when compared with no-neurosyphilis group. There was no correlation between serum and CSF concentrations of IL-17A. However, CSF pleocytosis correlated positively with both CSF IL-17A (r = 0.4, P = 0.01) and IFN-&ggr; (r = 0.42, P = 0.01). Conclusions Increased CSF levels of IFN-&ggr; and IL-17A in syphilitic patients with CSF abnormalities suggest that cells of adaptive immunity (probably T-helper cells producing IFN-&ggr; and IL-17) may contribute to the inflammatory response associated with neurosyphilis. In addition, the lack of correlation between serum and CSF IL-17A levels suggests intrathecal production of this cytokine. Further studies are needed to establish the exact nature of the immune response accompanying neurosyphilis and its clinical significance.

Skewing toward Treg and Th2 responses is a characteristic feature of sustained remission in ANCA-positive granulomatosis with polyangiitis

The objective of our study was to evaluate the T‐helper (Th) and regulatory T (Treg) cell profile in ANCA‐positive granulomatosis with polyangiitis (GPA) and its relation to disease activity. In a prospective study, we studied two groups of GPA patients: (i) disease flare (active‐GPA, BVAS>6, n = 19), (ii) sustained remission (≥ 1‐year prior enrollment, inactive‐GPA, BVAS = 0, n = 18). 24 age‐sex matched healthy subjects served as controls. Active‐GPA patients were followed for 6 months and reevaluated during remission (early remission; n = 13). We analyzed subsets of Th‐cells (flow cytometry), production of signature cytokines by in vitro stimulated lymphocytes, and broad spectrum of serum cytokines (Luminex). In all GPA patients we observed expansion of effector Th17 cells, and increased production of IL‐17A by in vitro stimulated T cells, as compared to controls. Disease flare was characterized by marked reduction in Treg cells, whereas in sustained remission we showed expansion of both Treg and Th2 subset. Finally, analyzing the cytokine profile, we identified CCL23 and LIGHT, as potential biomarkers of active disease. We conclude that in GPA, expansion of Treg and Th2 lymphocytes in parallel to increased Th17 response is a characteristic feature of sustained remission. In contrast, Treg cells are markedly decreased in disease flare.