Pro-inflammatory cytokines may induce late preconditioning in unstable angina patients

Modification of Ischemia/Reperfusion-Induced Alterations in Subcellular Organelles by Ischemic Preconditioning

It is now well established that ischemia/reperfusion (I/R) injury is associated with the compromised recovery of cardiac contractile function. Such an adverse effect of I/R injury in the heart is attributed to the development of oxidative stress and intracellular Ca²⁺-overload, which are known to induce remodeling of subcellular organelles such as sarcolemma, sarcoplasmic reticulum, mitochondria and myofibrils. However, repeated episodes of brief periods of ischemia followed by reperfusion or ischemic preconditioning (IP) have been shown to improve cardiac function and exert cardioprotective actions against the adverse effects of prolonged I/R injury. This protective action of IP in attenuating myocardial damage and subcellular remodeling is likely to be due to marked reductions in the occurrence of oxidative stress and intracellular Ca²⁺-overload in cardiomyocytes. In addition, the beneficial actions of IP have been attributed to the depression of proteolytic activities and inflammatory levels of cytokines as well as the activation of the nuclear factor erythroid factor 2-mediated signal transduction pathway. Accordingly, this review is intended to describe some of the changes in subcellular organelles, which are induced in cardiomyocytes by I/R for the occurrence of oxidative stress and intracellular Ca²⁺-overload and highlight some of the mechanisms for explaining the cardioprotective effects of IP.

Tefillin use induces remote ischemic preconditioning pathways in healthy men

The present study assessed whether tefillin use (tight, nonocclusive, wrapping of the arm) elicits a remote ischemic preconditioning (RIPC)-like effect in subjects with both acute and chronic use. RIPC, created by short bursts of ischemia-reperfusion, has not been successfully taken to the bedside. Several large population studies have found that Orthodox Jewish men (who wear tefillin almost daily) have decreased cardiovascular mortality compared with non-Orthodox counterparts. We hypothesized that tefillin use is a relevant component in triggering a preconditioning effect. Jewish men ( n = 20) were enrolled; 9 men were daily tefillin users (conditioned) and 11 men were nonusers of tefillin as controls (naïve). Subjects were evaluated for adherence to traditional Jewish practice, had vital signs measured, blood drawn for analysis of circulating cytokines and monocyte function, and underwent brachial flow-mediated dilation to evaluate vascular reactivity at baseline (basal) and after 30 min of using tefillin (acute treatment). Under basal conditions, both groups had similar peak systolic velocity (SV), diameter, and flow volume, although the conditioned group had higher SV at 120 s postdeflation ( P = 0.05). Acute tefillin use augmented artery diameter and flow volume in both groups, with conditioned subjects experiencing higher SV than control subjects at 90 and 120 s postdeflation ( P = 0.03 and P = 0.02, respectively). Conditioned subjects had decreased inflammation, monocyte migration and adhesion, and endothelial activation compared with control subjects at baseline. Acute use of tefillin did not significantly alter monocyte function in either group. In this pilot study, acute tefillin use improves vascular function, whereas chronic tefillin use is associated with an anti-inflammatory RIPC-like phenotype. NEW & NOTEWORTHY We hypothesized that tefillin use among Orthodox Jewish men (who practice a nonocclusive leather banding of their nondominant arm) will induce a remote ischemic preconditioning phenotype. Chronic use of tefillin in Orthodox Jewish men was associated with increased systolic velocity and attenuated inflammation and monocyte chemotaxis and adhesion versus Jewish men who do not wear tefillin. Acute use of tefillin in both populations augmented brachial artery diameter and blood flow but not inflammatory profiles compared with baseline.

A systematic review and meta-analysis of the cardioprotective effects of remote ischaemic preconditioning in open cardiac surgery

OBJECTIVE

To investigate the cardioprotective efficacy of remote ischaemic preconditioning (RIPC) in cardiac surgery.

DESIGN

We have performed a systematic search of MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials to identify randomized controlled trials involving RIPC.

SETTING

Randomized controlled trials of RIPC in open cardiac surgery patients.

MAIN OUTCOME MEASURES

Meta-analysis was performed with the primary outcome the standardized mean difference between intervention and control groups in 12 hour postoperative troponin concentration. Heterogeneity was examined by fixed effects meta-regression.

RESULTS

Ten studies with a total of 693 participants were included in the meta-analysis. RIPC reduced troponin levels 12 hours after surgery compared with control. The fixed and random effects differences were 0.35 (95% CI 0.19 to 0.51) and 0.53 (95% CI 0.18-0.88) respectively. However, important heterogeneity was present. Fixed effects meta-regression partially accounted for heterogeneity based on whether studies had full blinding, comprising blinding of patients, surgeons, anaesthetists and investigators. Studies with incomplete or no blinding demonstrated a larger estimate of effect, 0.74 (95% CI 0.47 to 1.00) compared to those with full blinding, 0.13 (95% CI - 0.07 to 0.33).

CONCLUSIONS

Although our analysis suggests RIPC may result in cardiac protection during cardiac surgery, the effect was most marked in studies without full blinding, with a smaller and statistically non-significant effect in fully blinded studies. We propose that further double blind randomized controlled trials investigating the cardioprotective effects of RIPC in cardiac surgery are required to resolve the current clinical uncertainty.

Association of interleukin-6 gene polymorphism with angina pectoris

In this study, we investigated the role of the -174G>C polymorphism of interleukin-6 (IL-6) as a predisposing factor to angina pectoris. Patients were separated into 2 groups: angina (N = 72) and nonangina (N = 71). There were no statistical differences between groups for all cardiovascular risk factors evaluated. The GG genotype frequency was 18% lower in the angina than in the non-angina group, whereas GC + CC was 18% higher in the angina group (P = .036). The frequency of G allele was 11% lower in the angina than in the nonangina group and C allele was 11% higher in the angina group (P = .043). Patients carrying the C allele showed a 2-fold increased risk for angina pectoris (P = .036). Our study demonstrates a high incidence of the -174G>C polymorphism of the IL-6 gene in patients with angina pectoris compared with those carrying the G allele, reinforcing the contribution of genetic factors to the symptoms of angina pectoris.