[Extracellular matrix of the heart and its changes in myocardial fibrosis]

Matrisome Transcriptome Dynamics during Tissue Aging

The extracellular matrix (ECM) is a complex three-dimensional network of macromolecules that provides structural support for the cells and plays a significant role in tissue homeostasis and repair. Growing evidence indicates that dysregulation of ECM remodeling contributes to various pathological conditions in the body, including age-associated diseases. In this work, gene expression data of normal human tissues obtained from the Genotype-Tissue Expression project, as well as data from MatrisomeDB 2.0, the ECM-protein knowledge database, are used to estimate the age-dependent matrisome transcriptome dynamics in the blood, heart, brain, liver, kidneys, lungs, and muscle. Differential gene expression (DE) analysis revealed dozens of matrisome genes encoding both structural elements of the ECM and ECM-associated proteins, which had a tissue-specific expression profile with age. Among common DE genes that changed expression with age in at least three tissues, COL18A1, MFAP1, IGFBP7, AEBP1, LTBP2, LTBP4, LG14, EFEMP1, PRELP, BGN, FAM20B, CTSC, CTSS, and CLEC2B were observed. The findings of the study also reveal that there are sex-specific alterations during aging in the matrisome gene expression. Taken together, the results obtained in this work may help in understanding the role of the ECM in tissue aging and might prove valuable for the future development of the field of ECM research in general.

Apigenin inhibits isoproterenol‐induced myocardial fibrosis and Smad pathway in mice by regulating oxidative stress and miR‐122‐5p/155‐5p expressions

Apigenin, a flavonoid isolated from Apium graveolens, is an effective natural active ingredient that inhibits transforming growth factor-β1 (TGF-β1)-induced cardiac fibroblasts (CFs) differentiation and collagen synthesis. However, its effects on isoproterenol-induced myocardial fibrosis in mice remain unknown. This study aimed to examine the effect of apigenin in the prevention of myocardial fibrosis. A mouse model of myocardial fibrosis induced by isoproterenol was established, and the mice were given apigenin 75-300 mg/kg orally for 40 days. The results showed that the heart weight coefficient, myocardial hydroxyproline, collagen accumulation, and malondialdehyde levels in the apigenin-treated groups were significantly reduced. In contrast, the activity of myocardial superoxide dismutase and glutathione peroxidase were significantly enhanced. The results of real-time quantitative polymerase chain reaction and western blot assays showed that apigenin could significantly upregulate the expressions of myocardial microRNA-122-5p (miR-122-5p), c-Ski, and Smad7 and downregulate the expressions of myocardial miR-155-5p, α-smooth muscle actin, collagen I/III, NF-κB, TGF-β1, hypoxia-inducible factor-1α (HIF-1α), Smad2/3, and p-Smad2/3. In vitro, the differentiation and extracellular matrix production, as well as TGF-β1/Smads axis, were further reduced after treatment of miR-122-5p mimic or miR-155-5p inhibitor-transfected and TGF-β1-stimulated CFs with apigenin. These results suggested that apigenin increased the expression of miR-122-5p and decreased the expression of miR-155-5p, which subsequently downregulated and upregulated the target genes HIF-1α and c-Ski, respectively. Furthermore, apigenin administration downregulated TGF-β1-induced Smad2/3 and upregulated Smad7. In addition, it reduced the NF-κB/TGF-β1 signaling pathway axis by increasing antioxidant ability to exert the antifibrotic effects.

Transforming Growth Factor β1 and Myocardial Remodeling in Patients with Chronic Heart Failure of Ischemic Genesis

Aim. To study the presence and nature of correlations between the level of transforming growth factor β1 (TFR-β1) and structural and functional parameters of the heart in the development of myocardial remodeling and fibrosis in patients with chronic heart failure (CHF) of ischemic origin.

Material and methods. The study included 120 men with class II-IV CHF who have history of myocardial infarction, which are divided into 3 groups depending on the CHF class. The control group included 25 healthy men. Assessment of left ventricular (LV) structural-functional state was carried out by echocardiography. Investigation of TFR-β1 and N-terminal precursor indices of cerebral natriuretic peptide (NT-pro BNP) was performed by enzyme immunoassay.

Results. Patients with class II-IV CHF were hyperexpression of ТФР-β1, the levels of which increased significantly as NYHA class increased and CHF progressed. The most significant structural-geometric rearrangement of LV and hyperactivation ТФР-β1 recorded in patients with class IV CHF (77.2±6.33 ng/ml with class IV CHF versus 46.7±3.74 ng/ml and 58.9±4.75 ng/ml with class II and III CHF; р< 0.05). In patients of class III-IV CHF, correlation relationships between ТФР-β1 level and echocardiographic parameters (LV myocardial mass index are established: r = 0.56, p = 0.05; end systolic volume index: r = 0.52, p = 0.05; value of LV ejection fraction: r = -0.48, p=0,05). Significant direct relationships are established in patients with class III-IV CHF between ТФР-β1 level and NT-rgo BNP levels (r=0,44; р=0,05).

Conclusion. The intensity of myocardial remodeling and fibrosis processes in patients with a progressive course of CHF is related to ТФР-β1 hyperexpression and is associated with a high level of activity of natriuretic peptides.