Altered Maturation Status and Possible Immune Exhaustion of CD8 T Lymphocytes in the Peripheral Blood of Patients Presenting With Acute Coronary Syndromes.

OBJECTIVE: Inflammation in response to oxidized lipoproteins is thought to play a key role in acute coronary syndromes (ACS), but the pattern of immune activation has not been fully characterized. We sought to perform detailed phenotypic and functional analysis of CD8 T lymphocytes from patients presenting with ACS to determine activation patterns and potential immunologic correlates of ACS. APPROACH AND RESULTS: We used polychromatic flow cytometry to analyze the cytokine production profiles of naïve, effector, and memory CD8 T cells in patients with ACS compared with control subjects with stable coronary artery disease. ACS was associated with an altered distribution of circulating CD8(+) T-cell maturation subsets with reduced proportions of naïve cells and expansion of effector memory cells. ACS was also accompanied by impaired interleukin-2 production by phenotypically naïve CD8 T cells. These results were validated in a second replication cohort. Naïve CD8 cells from patients with ACS also had increased expression of programmed cell death-1, which correlated with interleukin-2 hypoproduction. In vitro, stimulation of CD8 T cells with oxidized low-density lipoprotein was sufficient to cause programmed cell death-1 upregulation and diminished interleukin-2 production by naïve CD8 T cells. CONCLUSIONS: In this exploratory analysis, naïve CD8(+) T cells from patients with ACS show phenotypic and functional characteristics of immune exhaustion: impaired interleukin-2 production and programmed cell death-1 upregulation. Exposure to oxidized low-density lipoprotein recapitulates these features in vitro. These data provide evidence that oxidized low-density lipoprotein could play a role in immune exhaustion, and this immunophenotype may be a biomarker for ACS.

Scaling up the ex vivo expansion of human circulating CD34(+)progenitor cells with upregulation of angiogenic and anti-inflammatory potential.

BACKGROUND AIMS: The therapeutic application of CD34+ circulating progenitor cells (which includes endothelial progenitor cells) has been hampered by the quantity and quality of isolated circulating CD34(+) cells from the patient's peripheral blood. Our group had previously established a suspension culture system for human CD34(+) cells, with increased quantity and quality (QQ) of the angiogenic cell product. We successfully scaled up the expansion process with the use of culture bags because there is the need to move toward a dynamic and fully controlled bioreactor system to meet Good Manufacturing Practice (GMP) standards and attain clinically meaningful cell doses in a time- and cost-effective way. METHODS: CD34(+) cells isolated from mobilized peripheral blood of healthy donors were expanded ex vivo for 7 days in QQ medium (serum-free) in cell culture bags (30 mL) and pre- and post-expansion cells were characterized by means of flow cytometry and quantitative polymerase chain reaction; angiogenic potential was assessed by use of the in vitro tube formation assay. RESULTS: Our data show effective expansion of the cultured population (7-fold) while maintaining the stem/progenitor content and increasing the endothelial population. Moreover, post-expanded cells showed higher tube formation capacity compared with pre-expanded cells. In addition, an upregulation of the anti-inflammatory gene expression and a downregulation of pro-inflammatory genes were observed, which suggests that the increase in angiogenic potential is not paired with an increase in the inflammatory profile. CONCLUSIONS: The QQ expansion method was successfully scaled up to cell culture bags and was able to meet GMP standards, with a higher in vitro angiogenic profile.

Troponin levels after cardiac electrophysiology procedures: review of the literature.

Cardiac-specific Troponins (cTn) I and T have become markers of choice for myocardial injury. We reviewed the literature in order to understand the expected postprocedure cTn rise after electrophysiology procedures. A total of 34 studies and 1,608 patients were included. After external monophasic cardioversion, seven of 442 patients (1.6%) had minimal increase in cTnI (0.1-0.9 ng/mL), and only one of 368 (0.3%) had increase in cTnT (0.11 ng/mL). After internal cardioversion, 17 of 105 (16%) had increase in cTnI (0.7-2.4 ng/mL) but only three (2.9%) were above the cutoff for myocardial infarction (MI) (1.5 ng/mL). During implantable cardioverter-defibrillator (ICD) installation with a mean of 2-7 ICD shocks, 12 of 74 (16%) patients had cTnI >or=1.5 ng/mL (range 1.7-5.5 ng/mL) and 20 of 64 (32%) had cTnT >or=0.1 ng/mL (range 0.26-6.46 ng/mL) considered in the range of clinical MI. Radio frequency ablation (RFA) (n = 496) resulted in significant cTn elevation in 25-100% of patients with ventricular > atrial and linear > focal lesions. Average postprocedure peak cTnI ranged from 0.13 to 6 ng/mL (median: 2.36 ng/mL, max: 15 ng/mL) and cTnT 0.2 to 2.41 ng/mL (median: 0.44 ng/mL, max: 9 ng/mL). Early cTn peak at 2-8 hours was noted after RFA. External cardioversion should not cause a significant increase in cTn; RFA and ICD implantation with shocks often result in an increase in cTn. Interpretation of these markers can be difficult if acute coronary syndrome is suspected in the postprocedure period.