SIRT1 confers protection against ischemia/reperfusion injury in cardiomyocytes via regulation of uncoupling protein 2 expression.

The development of a novel targeted therapy for acute myocardial infarction (AMI) remains a major hurdle in the treatment of cardiovascular disease. Previous studies indicate that mitochondrial uncoupling protein 2 (UCP­2) is involved in the progression of AMI. The present study uses lentivirus knockdown of Sirtuin 1 (SIRT1) in H9c2 cells under hypoxia conditions, and revealed that levels of SIRT1 are accompanied by the expression of UCP­2. Therefore, it was hypothesized that SIRT1 might be important in the development of myocardial infarction. The present study demonstrated that: i) exogenous expression of SIRT1 in vitro induced resistance to hypoxic injury in H9c2 cells, coinciding with a reduction in expression of UCP­2; ii) knockdown of UCP­2 conferred resistance to hypoxic injury in H9c2; iii) intraperitoneal injection of resveratrol and the resultant increase in SIRT1 levels may protect against ischemia/reperfusion injury in vivo, concomitant with decreased expression of UCP­2. These findings provide direct evidence that the SIRT1/UCP­2 axis might be important in myocardial infarction, and suggest that this axis may be a novel therapeutic target for the treatment of cardiovascular disease.

Two cases of non-intervention-related vascular intense spasm following stent implantation in the coronary artery.

The clinical occurrence of non-intervention-related vascular spasm following coronary stenting is rare. In the present study, 2 cases are reported. One patient developed continuous spasms in the proximal segment of the left anterior descending (LAD) and left circumflex (LCX) arteries following LAD artery stenting. The second patient developed an intense spasm in the right coronary artery (RCA) following LAD artery stenting. Clinical course and prognosis are dangerous. The main treatment for this condition is a combination of repeated injections of nitroglycerin into the coronary artery and the administration of calcium antagonists. In the clinic, intervention-related vascular spasms are common in percutaneous coronary intervention (PCI) due to the mechanical stimulation caused by balloon dilatation or stent expansion. Injections of a vasodilator into the coronary artery are able to mitigate the spasms and the consequent prognosis is good.

Repeated intracoronary infusion of peripheral blood stem cells with G-CSF in patients with refractory ischemic heart failure--a pilot study.

BACKGROUND: Recent investigations have suggested the clinical efficacy of granulocyte colony-stimulating factor (G-CSF) infusion alone or in combination with a single dose delivery of peripheral blood stem cells (PBSC) infusion in patients with myocardial infarction (MI) and congestive heart failure (HF). The current study tested the feasibility and effect of repeated intracoronary infusions PBSC and the mobilization of G-CSF in patients with refractory HF after MI. METHODS AND RESULTS: Patients with recent large MI and a lower left ventricular ejection fraction (LVEF) were enrolled into one of the following 3 groups: Group R (n=15) received repeated intracoronary infusion of PBSC and one-dose of G-CSF; Group S (n=15) received a single infusion of PBSC and a G-CSF dose; and Group C (n=15) received neither PBSC nor a G-CSF dose. Cardiac performance was evaluated by echocardiography and single photon-emission computed tomography (SPECT). All the patients underwent 12-month follow-up. LVEF in Group R (47.00±4.90%) was significantly higher than that in Group S (44.40±3.87%, P<0.01) and Group C (40.80±3.41%, P<0.01). Similarly, the improvement of myocardial perfusion assessed by SPECT in Group R was more than that in Group S (P=0.012) and Group C (P<0.01). Neither death nor new MI occurred. CONCLUSIONS: Repeated intracoronary infusions of PBSC plus mobilization of G-CSF might be an optional effective strategy for treating patients with refractory HF after recent large MI.

[Evaluation of neointimal coverage and thrombosis at 3 months and 2 years post sirolimus-eluting stent implantation by optical coherence tomography].

OBJECTIVE: To evaluate the short- and long-term prevalence of persistent uncovered struts and in-stent thrombus after sirolimus-eluting stent (SES) implantation by optical coherence tomography (OCT). METHODS: OCT was performed for 31 SES in 21 patients at 3 months and for 30 SES in 21 patients at 2 years post SES implantation. Thickness of new intima inside each strut was measured and thickness equal to 0 microm was defined as an uncovered strut. Existence of in-stent thrombus was also evaluated. RESULTS: A total of 4545 struts and 3707 struts were evaluated at 3 months and at 2 years post SES implantation, respectively. New intima at 2 years was significantly thicker than that at 3 months [(71 +/- 93) microm vs. (29 +/- 41) microm, P < 0.01]. Percent of uncovered struts at 2 years was significantly lower than that at 3 months (5% vs. 15%, P < 0.01). Prevalence of uncovered struts was similar at 2 years and at 3 months (81% vs.95%, P > 0.05). Subclinical thrombus was recognized in 14% patients at 3 months and 2 years post SES implantation. CONCLUSIONS: Neointimal coverage inside the SES is a continuous process and the number of uncovered struts decreased from 3 months to 2 years after SES implantation. Few uncovered struts could still be visualized in the majority of patients at 2 years post SES implantation.

[Finite element analysis of stress changes of posterior spinal pedicle screw infixation].

OBJECTIVE: To evaluate the mechanical response of L3-L4 segment after posterior interfixation with a transpedicle screw system. METHODS: Spiral CT machine was used to conduct continuous parallel scan on the L3-L4 section of a 40-year-old healthy male Chinese. The image data thus obtained were introduced into MIMICS software to reconstruct the 2-D data into volume data and obtain 3-D models of every element.. Pro/3-D model construction software system was used to simulate the 3-D entity of L3-L4 fixed by screw robs through spinal pedicle via posterior approach that was introduced into the finite element software ABAQUS to construct a 3-D finite element model. The stress changes on the vertebrae and screw under the axial pressure of 0.5 mPa was analyzed. RESULTS: Under the evenly distributed pressure the displacement of the L4 model was 0.00125815 mm, with an error of only 0.8167% from the datum displacement. The convergence of the model was good. The stress of the fixed vertebral body, intervertebral disc, and internal fixators changed significantly. The stress concentration zone of the intervertebral disc turned from the posterolateral side to anterolateral side. The stress produced by the fixed vertebral bodies decreased significantly. Obvious stress concentration existed in the upper and lower sides of the base of screw and the fixed screw at the upper vertebral body bore greater stress than the lower vertebral body. CONCLUSIONS: Integration of computer aided device and finite element analysis can successfully stimulate the internal fixation of L3-IA visa posterior approach and observe the mechanic changes in the vertebral column more directly.