Comparison of high-sensitivity cardiac troponin I and T for the prediction of cardiac complications after non-cardiac surgery.

BACKGROUND: We aimed to directly compare preoperative high-sensitivity cardiac troponin (hs-cTn) I and T concentration for the prediction of major cardiac complications after non-cardiac surgery. METHODS: We measured hs-cTnI and hs-cTnT preoperatively in a blinded fashion in 1022 patients undergoing non-cardiac surgery. The primary endpoint was a composite of major cardiac complications including cardiac death, cardiac arrest, myocardial infarction, clinically relevant arrhythmias, and acute heart failure within 30 days. We hypothesized that the type of surgery may impact on the predictive accuracy of hs-cTnI/T and stratified all analyses according to the type of surgery. RESULTS: Major cardiac complications occurred in 108 (11%) patients, 58/243 (24%) patients undergoing vascular surgery and 50/779 (6%, P < .001) patients undergoing non-vascular surgery. Using regulatory-approved 99th percentile cut-off concentrations, preoperative hs-cTnI elevations were less than one-fifth as common as preoperative hs-cTnT elevations (P < .001). Among patients undergoing vascular surgery, preoperative hs-cTnI concentrations, but not hs-cTnT, was an independent predictor of cardiac complications (adjusted odds ratio (aOR) 1.5, 95% confidence interval (95% CI) 1.0-2.1). The area under the receiver-operating characteristics curve (AUC) was 0.67 (95% CI, 0.59-0.75) for hs-cTnI versus 0.59 (95% CI 0.51-0.67, P = .012) for hs-cTnT. In contrast, among patients undergoing non-vascular surgery both preoperative hs-cTnI and hs-cTnT were independent predictors of the primary endpoint (aOR 1.6, 95% CI 1.3-2.0, and aOR 3.0, 95% CI 2.0-4.6, respectively) and showed higher predictive accuracy (AUC 0.77, 95% CI, 0.71-0.83, and 0.79, 95% CI 0.73-0.85, P = ns). CONCLUSIONS: Preoperative hs-cTnI and hs-cTnT concentrations predict major cardiac complications after non-vascular surgery, while, in patients undergoing vascular surgery, hs-cTnI may have better accuracy.

Adhesion and protease activity in cell lines from human salivary gland tumors are regulated by the laminin-derived peptide AG73, syndecan-1 and beta1 integrin.

We studied the induction of protease activity by the laminin alpha1-derived peptide AG73 in cells from adenoid cystic carcinoma (CAC2) and myoepithelioma (M1), respectively a malignant and a benign salivary gland tumors. Laminin alpha1 chain and MMP9 were immunolocalized in adenoid cystic carcinoma and myoepithelioma in vivo and in vitro. Cells grown inside AG73-enriched laminin-111 exhibited large spaces in the extracellular matrix, suggestive of remodeling. The broad spectrum MMP inhibitor GM6001 decreased spaces induced by AG73 in CAC2 and M1 cells. This result strongly suggests that AG73-mediated matrix remodeling involves matrix metalloproteinases. CAC2 and M1 cells cultured on AG73 showed a dose-dependent increase of MMP9 secretion, as detected by zymography. Furthermore, siRNA silencing of MMP9 decreased remodeling in 3D cultures. We searched for AG73 receptors regulating MMP9 activity in our cell lines. CAC2 and M1 cells grown on AG73 exhibited colocalization of syndecan-1 and beta1 integrin. siRNA knockdown of syndecan-1 expression in these cells resulted in decreased adhesion to AG73 and reduced protease and remodeling activity. We investigated syndecan-1 co-receptors in both cell lines. Silencing beta1 integrin inhibited adhesion to AG73, matrix remodeling and protease activity. Double-knockdown experiments were carried out to further explore syndecan-1 and beta1 integrin cooperation. CAC2 cells transfected with both syndecan-1 and beta1 integrin siRNA oligos showed significant decrease in adhesion to AG73. Simultaneous silencing of receptors also induced a decrease in protease activity. Our results suggest that syndecan-1 and beta1 integrin signaling downstream of AG73 regulate adhesion and MMP production by CAC2 and M1 cells.

Endotoxin tolerance: selective alterations in gene expression and protection against lymphocyte death.

Extensive lymphocyte apoptosis may be an important cause of immune suppression in sepsis. Here we investigated the effect of LPS tolerance on lymphocyte apoptosis in an experimental model of polymicrobial infection. Tolerance was induced by the injection of lipopolysaccharide (1.0mg/kg/subcutaneously) once a day for 5 days. Macroarray analysis of mRNA isolated from T-(CD4) lymphocytes was used to identify genes that are differentially expressed during LPS tolerance. In addition, assessment of the expression of apoptosis-associated lymphocyte gene products and apoptotic events was performed on the 8th day; 6h after the terminal challenge with polymicrobial infection or high-dose LPS administration. Survival studies with polymicrobial infection were also conducted. LPS tolerance induced a broad reprogramming of cell death pathways, including a suppression of receptor-mediated and mitochondrial apoptotic pathways, inflammatory caspases, alternate apoptotic pathways, as well as reduced expression of genes involved in necrosis. These alterations led to a marked resistance of lymphocytes against cell death during the subsequent period of sepsis. In addition, LPS tolerance produced an increased differentiation of T-lymphocytes to T(H)1 and T(H)2, with a T(H)1 differentiation predominance. Thus, in the current study we provide an evidence for a marked reprogramming of gene expression of multiple cell death pathways during LPS tolerance. These alterations may play a significant role in the observed protection of the animals from a subsequent lethal polymicrobial sepsis challenge.