Inhomogeneity of collagen organization within the fibrotic scar after myocardial infarction: results in a swine model and in human samples.

We aimed to characterize the organization of collagen within a fibrotic scar in swine and human samples from patients with chronic infarctions. Swine were subjected to occlusion of the left anterior descending artery followed by reperfusion 1 week (acute myocardial infarction group) or 1 month (chronic myocardial infarction group) after infarction. The organization of the collagen fibers (Fast Fourier Transform of samples after picrosirius staining; higher values indicate more disorganization) was studied in 100 swine and 95 human samples. No differences in collagen organization were found between the acute and chronic groups in the core area of the scar in the experimental model. In the chronic group, the endocardium [0.90 (0.84-0.94); median (interquartile range)], epicardium [0.84 (0.79-0.91)] and peripheral area [0.73 (0.63-0.83)] displayed a much more disorganized pattern than the core area of the fibrotic scar [0.56 (0.45-0.64)]. Similarly, in human samples, the collagen fibers were more disorganized in all of the outer areas than in the core of the fibrotic scar (P < 0.0001). Both in a highly controlled experimental model and in patient samples, collagen fibers exhibited an organized pattern in the core of the infarction, whereas the outer areas displayed a high level of inhomogeneity. This finding contributes pathophysiological information regarding the healing process and may lead to a clearer understanding of the genesis and invasive treatment of arrhythmias after acute myocardial infarction.

Serum heat shock protein 60 in acute heart failure: a new biomarker?

Heat shock protein 60 (HSP60) is a mitochondrial protein constitutively expressed in the majority of cells, and its expression is up-regulated by a variety of stressors. In heart failure, HSP60 is released from cardiomyocytes. The authors speculate that increased serum HSP60 (sHSP60) may be related to the severity of heart failure. This investigation sought to assess the association between sHSP60 and the composite end point of death/readmission in patients with acute heart failure (AHF). A total of 132 consecutive patients were admitted for AHF. The independent association between sHSP60 and the end point was assessed with Cox regression. During a median follow-up of 7 months (interquartile range, 3-14), 35 (26.5%) deaths, 40 (30.3%) readmissions, and 65 (49.2%) deaths/readmission were identified. Patients who exhibited the outcome showed higher median sHSP60 values (6.15 ng/mL [8.49] vs 4.71 ng/mL [7.55] P=.010). A monotonic increase in the incidence of the composite end point was observed when moving from lower to higher tertile (4.74, 4.76, and 6.98 per 10 patients-years of follow-up, P for trend <.001). After adjusting for established risk factors, only patients in the upper tertile showed an increased risk of death/readmission (hazard ratio, 2.63; 95% confidence interval, 1.29-5.37; P=.008). In patients with AHF, high sHSP60 was related to a higher risk for subsequent death/readmission for AHF.