Altered trafficking of CD8+ memory T cells after implantation of rapamycin-eluting stents in patients with coronary artery disease

The CD4/CD8 ratio is associated with coronary artery disease (CAD) in elderly Chinese patients

OBJECTIVE

The aim of this study was to investigate the relationship between number of circulating T cells and coronary artery disease (CAD) in an elderly Chinese population.

METHODS

A total of 295 elderly inpatients (age≥60) were included in this cross-sectional study. Their clinical and biochemical characteristics were recorded. Patients were divided to two groups: control patients and CAD patients. The risk factors of CAD were explored by binary logistic regression analysis.

RESULTS

Compared with control patients, the ratio of CD4 to CD8 T cells was significantly increased in CAD patients. There was no difference in the number of CD3, CD4, and CD8 T cells between the two groups. Multiple logistic regression analysis showed that CAD was independently associated with age, gender, body mass index (BMI), systolic blood pressure (SBP), chronic heart failure (CHF) and the CD4/CD8 ratio. In addition, after adjusting for different clinical parameters (including gender, age, CHF, hypertension, arrhythmia, SBP, and BMI), the risk of CAD was significantly increased in patients with a CD4/CD8 ratio>1.5.

CONCLUSIONS

There was a strong and independent association between the ratio of CD4/CD8 and CAD in elderly Chinese population.

Enhanced neointima formation following arterial injury in immune deficient Rag-1-/- mice is attenuated by adoptive transfer of CD8 T cells

T cells modulate neointima formation after arterial injury but the specific T cell population that is activated in response to arterial injury remains unknown. The objective of the study was to identify the T cell populations that are activated and modulate neointimal thickening after arterial injury in mice. Arterial injury in wild type C57Bl6 mice resulted in T cell activation characterized by increased CD4⁺CD44^hi and CD8⁺CD44^hi T cells in the lymph nodes and spleens. Splenic CD8⁺CD25⁺ T cells and CD8⁺CD28⁺ T cells, but not CD4⁺CD25⁺ and CD4⁺CD28⁺ T cells, were also significantly increased. Adoptive cell transfer of CD4⁺ or CD8⁺ T cells from donor CD8−/− or CD4−/− mice, respectively, to immune-deficient Rag-1−/− mice was performed to determine the T cell subtype that inhibits neointima formation after arterial injury. Rag-1−/− mice that received CD8⁺ T cells had significantly reduced neointima formation compared with Rag-1−/− mice without cell transfer. CD4⁺ T cell transfer did not reduce neointima formation. CD8⁺ T cells from CD4−/− mice had cytotoxic activity against syngeneic smooth muscle cells in vitro. The study shows that although both CD8⁺ T cells and CD4⁺ T cells are activated in response to arterial injury, adoptive cell transfer identifies CD8⁺ T cells as the specific and selective cell type involved in inhibiting neointima formation.

Predictive value of preintervention C-reactive protein on clinical outcome after directional coronary atherectomy followed by stent implantation

BACKGROUND

Preprocedural C-reactive protein (CRP) serum levels have been shown to predict the recurrence of angina or major adverse cardiac events after percutaneous coronary intervention. Directional coronary atherectomy (DCA), by reducing residual plaque burden and restenosis, has been shown to improve clinical outcome after coronary stenting. Thus, we assessed the influence of preprocedural CRP serum levels on the recurrence of cardiac events after DCA followed by bare metal stent implantation.

METHODS

We enrolled 40 consecutive patients (34 males; 61+/-10 years old) with single-vessel disease who were undergoing DCA. In all patients, preprocedural CRP serum levels were measured by an ultrasensitive nephelometric method. The endpoint of the study was defined as the composite incidence of death, myocardial infarction, and recurrence of angina requiring repeat revascularization at 6-month follow-up.

RESULTS

CRP serum levels were a significant independent predictor of the composite endpoint at multiple regression analysis [odds ratio=1.69; 95% confidence interval (95% CI)=1.04-2.75; P=.033]. Patients with recurrence of cardiac events had CRP serum levels higher than those of patients not having events on follow-up [3.95 (2.2-5.7) vs. 2 (1.3-3.3); P=.05].

CONCLUSION

In conclusion, our study shows that baseline CRP serum levels predict cardiac events after coronary bare metal stenting despite plaque debulking with directional atherectomy.

Controlling the generation and function of human CD8+ memory T cells in vitro with immunosuppressants

BACKGROUND

Memory T cells play a pivotal role in acute and chronic rejection of transplanted organs. Novel therapies such as alemtuzumab and the identification of heterologous memory have highlighted their importance following transplantation. Unlike naive T cells, the influence of immunosuppressive agents on the de novo generation of memory T cells and on the function of pre-existing memory T cells is poorly understood.

METHOD

CD8 effector memory T cells (Tem, CD45RA, CCR7) were generated by stimulating peripheral blood mononuclear cells for five days with anti-CD3 and anti-CD28 monoclonal antibodies, followed by nine days of rest. The influence of immunosuppression on this was assessed by flow cytometry. Tem that had been naturally formed in vivo were used to study the influence of the same agents on the function (intracellular interferon-gamma production) of Tem cells.

RESULTS

Whereas all the immunosuppressive agents tested inhibited the expansion of CD8 Tem population by influencing their proliferation and apoptosis, the calcineurin inhibitors were better at controlling their function. Furthermore, Tem generated despite the presence of tacrolimus were functional and did not exhibit drug resistance.

CONCLUSIONS

Immunosuppressive agents differ in their ability to control the generation and function of CD8 Tem; the calcineurin inhibitors being the most efficacious. This may be of importance when tailoring immunosuppressants for transplant recipients, particularly in those where there is pre-existing immunological memory or in those receiving T-cell depleting therapies, which skews the immune repertoire towards memory.

Comparison between sirolimus- and paclitaxel-eluting stent in T-cell subsets redistribution

We sought to investigate the effects of 2 different coronary drug-eluting stents on the distribution of central or effector memory T cells circulating in the coronary sinus of patients with coronary artery disease who underwent percutaneous coronary revascularization. We randomly assigned 43 patients (mean age 65.4 +/- 4.3 years; 34 men) presenting with stable coronary disease and angiographically proved stenosis of the left anterior descending artery to treatment with sirolimus- or paclitaxel-eluting stents. Heparinized blood samples were obtained from the coronary sinus before and 20 minutes after stent implantation. Analysis of surface phenotype was performed by 4-color flow cytometry, and data are expressed as the percentage of positive cells. The percentages of CD8+ and CD4+ effector memory T cells, as defined by the CD3+CD45RO+CD27- phenotype, were significantly reduced in patients who received a sirolimus-eluting stent compared with the basal values. Conversely, the percentages of CD8+, but not CD4+, central memory T cells (CD3+CD45RO+CD27+) were increased in the same treatment group after the revascularization procedure. No changes in the percentages of memory T-cell populations in the paclitaxel-eluting stent group were observed. These findings show that sirolimus-eluting stents rapidly induced a redistribution of memory T lymphocytes, with a significant decrease of proinflammatory effector memory T cells circulating within the coronary sinus.