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Global Translational Medicine ECM receptor pathway in endotheliocytes after MI

fatality . Advances in MI treatment have resulted in a state of cells amidst pathological changes. In contrast,
[1]
decline in early mortality rates among patients. However, primary cells derived from animal models or patient
the impact of MI-induced cardiac fibrosis on patients’ samples offer a more faithful depiction of changes in
quality of life and long-term prognosis remains profound, cell state, cell phenotype, and specific protein expression
emerging as a crucial factor in cardiac remodeling and during pathological processes. However, the acquisition of
eventual progression to heart failure . The fibrotic process primary cells presents challenges, requiring larger sample
[2]
subsequent to MI unfolds in two stages. Early replacement sizes and more complex procedures. These challenges
fibrosis typically transpires within 1 – 2 weeks after MI, pose a critical hurdle in the current study. Fortunately,
characterized by the excessive deposition of extracellular this study successfully isolated primary ECs from mouse
matrix (ECM) following myocardial ischemia and necrosis. hearts, presenting valuable real-time samples for disease
This fibrotic process leads to the formation of scar tissue, research. The MI model was established by ligating the
serving as a protective shield for the heart’s integrity and left anterior descending branch of the coronary artery in
averting the risk of cardiac rupture [3,4] . In the majority mice, resulting in reactive fibrosis evident 14 days post-MI.
of cases, the necrosis and loss of myocardial cells do not Following successful modeling, primary ECs were isolated
precipitate heart failure directly. Instead, the occurrence of from mouse hearts for proteomic comparative analysis.
reactive fibrosis during the middle and late stages emerges This analysis aimed to explore the differences in cell
as the primary factor contributing to diminished cardiac phenotype and protein expression between the MI group
compliance, ventricular wall stiffness, cardiac dysfunction, and the sham group, identify potential signaling pathways
and, ultimately, heart failure [5,6] . The complexity of the impacting cardiac fibrosis, validate the findings, and assess
fibrosis mechanism, coupled with its contrasting early whether targeted interventions in these pathways could
protective effects and long-term development, poses reverse the fibrotic process. These findings may serve as a
significant challenges in devising effective treatment plausible target for future treatment strategies.
strategies .
[5]
At present, the predominant focus of research on the 2. Materials and methods
pathological progression and treatment of cardiac fibrosis 2.1. Establishment of an MI model, induction of
post-MI focuses on the involvement of immune cells, cardiac fibrosis, and isolation and purity validation
fibroblasts, and myofibroblasts in the development of of primary cardiac ECs
cardiac fibrosis. Activated fibroblasts, cardiomyocytes, and Male C57 mice, aged 8 weeks and weighing between 20 g
diverse immune cells release cytokines to polarize resident and 25 g, were procured from Weitong Lihua Experimental
macrophages and release chemokines to recruit additional Animal Center and maintained under SPF-grade animal
monocytes from the circulation [7,8] . Notably, various care conditions. An MI model was created by ligating
fibroblast factors, such as transforming growth factor-β, the left anterior descending coronary artery in the mice.
Ang II, and ET-1, have been identified as promoters of Following intubation, the mice were connected to a
the activation and proliferation of cardiac fibroblasts and ventilator, and a thoracic incision was made to expose
myofibroblasts, thereby leading to cardiac fibrosis [9,10] . This their hearts. The bottom edge of the left atrial appendage
process involves neurohumoral factors, the inflammatory was ligated using an 8-0 suture thread. The mice were
response, and oxidative stress, each assuming an important randomly allocated to two groups – the sham operation
role . Recent studies have revealed that endothelial cells group and the MI group – each consisting of 30 members.
[11]
(ECs) also contribute to cardiac fibrosis by secreting The sham operation group underwent identical surgical
these factors. In addition, ECs can undergo endothelial- procedures as the MI group, excluding the ligation of
mesenchymal transition, transforming into stromal cells the left anterior descending artery. Twenty-four hours
and subsequently transforming into fibroblasts, thereby post-surgery, six mice from each group were euthanized
exacerbating the development of cardiac fibrosis. However, under deep anesthesia and administered ice-cold PBS by
the specific mechanism governing this transformation gavage. Heart sections were then obtained and incubated
remains elusive. A recent study has demonstrated that a with a 1 – 2% 2,3,5-triphenyl-tetrazolium chloride (TTC)
majority of fibroblasts involved in the fibrotic process solution at 37℃ for 20 min. Fourteen days following the
originate from ECs . Consequently, further investigation MI, paraffinized heart sections from six mice in each group
[12]
into the role of ECs in cardiac fibrosis post-MI is warranted. were stained using Sirius Red. The remaining mice were
Previous studies on ECs have mainly used cultured dissected into pieces and treated with collagenase type II
endothelial cell lines to investigate changes in protein (prepared in Hank’s solution, concentration 1 – 2 mg/ml,
expression and phenotypic variations. However, cells at 37℃ for 30 – 45 min). Primary cardiac endothelial
cultured in vitro may not faithfully represent the authentic cells were subsequently isolated using CD31 magnetic

Volume 2 Issue 4 (2023) 2 https://doi.org/10.36922/gtm.2217