Ultrastructural morphometric findings of cardiomyocytes in patients with impaired ventricular function--a comparative clinicopathological study

Identification of myocardial diffuse fibrosis by 11 heartbeat MOLLI T 1 mapping: averaging to improve precision and correlation with collagen volume fraction

OBJECTIVES

Our objectives involved identifying whether repeated averaging in basal and mid left ventricular myocardial levels improves precision and correlation with collagen volume fraction for 11 heartbeat MOLLI T 1 mapping versus assessment at a single ventricular level.

MATERIALS AND METHODS

For assessment of T 1 mapping precision, a cohort of 15 healthy volunteers underwent two CMR scans on separate days using an 11 heartbeat MOLLI with a 5(3)3 beat scheme to measure native T 1 and a 4(1)3(1)2 beat post-contrast scheme to measure post-contrast T 1, allowing calculation of partition coefficient and ECV. To assess correlation of T 1 mapping with collagen volume fraction, a separate cohort of ten aortic stenosis patients scheduled to undergo surgery underwent one CMR scan with this 11 heartbeat MOLLI scheme, followed by intraoperative tru-cut myocardial biopsy. Six models of myocardial diffuse fibrosis assessment were established with incremental inclusion of imaging by averaging of the basal and mid-myocardial left ventricular levels, and each model was assessed for precision and correlation with collagen volume fraction.

RESULTS

A model using 11 heart beat MOLLI imaging of two basal and two mid ventricular level averaged T 1 maps provided improved precision (Intraclass correlation 0.93 vs 0.84) and correlation with histology (R 2 = 0.83 vs 0.36) for diffuse fibrosis compared to a single mid-ventricular level alone. ECV was more precise and correlated better than native T 1 mapping.

CONCLUSION

T 1 mapping sequences with repeated averaging could be considered for applications of 11 heartbeat MOLLI, especially when small changes in native T 1/ECV might affect clinical management.

Extract of Sheng-Mai-San Ameliorates Myocardial Ischemia-Induced Heart Failure by Modulating Ca2+-Calcineurin-Mediated Drp1 Signaling Pathways

Sheng-Mai-San (SMS) is a well-known traditional Chinese medicine (TCM) complex prescription used to treat heart failure (HF) and angina in clinic. However, its potential therapeutic mechanisms remain unclear. The present study evaluated the cardioprotection of extract of SMS (ESMS) on myocardial ischemia (MI)-induced HF, and explored the underlying molecular mechanisms. The results demonstrated that ESMS (728.0 mg/kg) significantly attenuated MI injury-induced HF by improving cardiac function and pathological changes, decreasing lactate dehydrogenase (LDH), creatine kinase (CK) activities, and brain natriuretic peptide (BNP) levels; increasing ATPase activity; and reducing intracellular Ca²⁺ levels in MI-induced HF mice model. It also significantly decreased the apoptotic index. In vitro, ESMS (400 μg/mL) inhibited mitochondrial-dependent myocardial apoptosis by modulating the expression of caspase-3 and the Bcl-2/Bax ratio, and improved mitochondrial function through increasing mitochondrial membrane potential and cellular ATP content. ESMS restored intracellular Ca²⁺ and downregulated the expression of Calcineurin A (CnA), thus inhibiting phosphorylation of dynamin-related protein 1 (Drp1) at Ser616 and increasing phosphorylation of Drp1 at Ser637 to prevent cardiomyocyte mitochondrial fission. Above-mentioned results demonstrated ESMS suppressed mitochondrial-mediated apoptosis in oxygen glucose deprivation (OGD) injured H9c2 cardiomyocytes. These findings suggested that ESMS attenuated MI-induced HF by regulating Ca²⁺ homeostasis and suppressing mitochondrial mediated apoptosis through the modulation of Ca²⁺-calcineurin-mediated Drp1 signaling pathways. Our results provide insight into the mechanism and clinical applications of SMS and suggest a potential therapeutic strategy for HF.