Single-Cell Transcriptomic Analysis Reveals Myocardial Fibrosis Mechanism of Doxorubicin-Induced Cardiotoxicity.

Myocardial fibrosis is a pathological feature of doxorubicin-induced chronic cardiotoxicity that severely affects the prognosis of oncology patients. However, the specific cellular and molecular mediators driving doxorubicin-induced cardiac fibrosis, and the relative impact of different cell populations on cardiac fibrosis, remain unclear.This study aimed to explore the mechanism of doxorubicin-induced cardiotoxicity and myocardial fibrosis and to find potential therapeutic targets. Single-cell RNA sequencing was used to analyze the transcriptome of non-cardiomyocytes from normal and doxorubicin-induced chronic cardiotoxicity in mouse model heart tissue.We established a mouse model of doxorubicin-induced cardiotoxicity with a well-defined fibrotic phenotype. Analysis of single-cell sequencing results showed that fibroblasts were the major origin of extracellular matrix in doxorubicin-induced myocardial fibrosis. Further resolution of fibroblast subclusters showed that resting fibroblasts were converted to matrifibrocytes and then to myofibroblasts to participate in the myocardial remodeling process in response to doxorubicin treatment. Ctsb expression was significantly upregulated in fibroblasts after doxorubicin-induced.This study provides a comprehensive map of the non-cardiomyocyte landscape at high resolution, reveals multiple cell populations contributing to pathological remodeling of the cardiac extracellular matrix, and identifies major cellular sources of myofibroblasts and dynamic gene-expression changes in fibroblast activation. Finally, we used this strategy to detect potential therapeutic targets and identified Ctsb as a specific target for fibroblasts in doxorubicin-induced myocardial fibrosis.

Pulmonary endarterectomy in patients with occlusive isolated pulmonary vasculitis.

BACKGROUND: Isolated pulmonary vasculitis (IPV) is a rare, insidious, and localized inflammatory disease affecting the pulmonary arteries, often leading to severe luminal obstruction. The prognosis for patients with occlusive IPV is poor, and there is currently a lack of effective treatments. The objective of this study was to evaluate the performance of pulmonary endarterectomy (PEA) as a treatment for occlusive IPV. METHODS: This single-center retrospective analysis included patients who received PEA for occlusive IPV between January 2018 and June 2022. Clinical characteristics and hemodynamic parameters were evaluated at baseline and follow-up. RESULTS: Among 114 consecutive patients who underwent PEA, occlusive IPV was identified in 7 patients. Two patients underwent bilateral PEA for the involvement of both pulmonary arteries. Patch angioplasty was performed to treat four severe constrictions. One patient died from residual pulmonary hypertension after limited PEA of a transmural vascular lesion. In addition, no obvious surgical complications were observed. Three months after PEA, a substantial relief in symptoms was achieved. Also, there is a decrease in the mean pulmonary artery pressure (median 33 [20-48] mmHg before versus median 21 [16-26] mmHg after; P < 0.018) and pulmonary arterial resistance (median 234 [131-843] dyn.s.cm-5 versus median 180 [150-372] dyn.s.cm-5; P = 0.310). Three patients experienced a relapse of restenosis of the treated arteries within a 6-month follow-up period, despite daily oral prednisolone administration. They were treated with balloon pulmonary angioplasty of both the main pulmonary arteries and branches. CONCLUSIONS: PEA is a valuable choice for treating occlusive IPV, with notable hemodynamic and clinical advantages. To increase long-term vascular patency, complete management should be optimized.

Single-Cell Transcriptome Sequencing Reveals Molecular Mechanisms of Renal Injury in Essential Hypertension.

INTRODUCTION: Hypertensive nephropathy is characterized by glomerular and tubulointerstitial damage, but we know little about changes in cell-specific gene expression in the early stages of hypertensive kidney injury, which usually has no obvious pathological changes. METHODS: We performed unbiased single-cell RNA sequencing of rat kidney samples from hypertensive kidney injury to generate 10,602 single-cell transcriptomes from 2 control and 2 early stage hypertensive kidney injury samples. RESULTS: All major cell types of the kidney were represented in the final dataset. Side-by-side comparisons showed that cell type-specific changes in gene expression are critical for functional impairment of glomeruli and tubules and activation of immune cells. In particular, we found a significantly reduced gene expression profile of maintaining vascular integrity in glomerular cells of hypertensive kidney injury. Meanwhile, the expression of genes associated with oxidative stress injury and fibrosis in the renal tubules and collecting ducts was elevated, but the degree of tubular cells response to injury differed between parts. We also found a signature of immune cell infiltration in hypertensive kidney injury. CONCLUSION: Exploring the changes of gene expression in hypertension-injured kidneys may be helpful to identify the early biomarkers and signal pathways of this disease. Our data provide rich resources for understanding the pathogenesis of hypertensive renal injury and formulating effective treatment strategies.

Application of Homograft Valved Conduit in Cardiac Surgery.

Valved conduits often correct the blood flow of congenital heart disease by connecting the right ventricle to the pulmonary artery (RV-PA). The homograft valved conduit was invented in the 1960s, but its wide application is limited due to the lack of effective sterilization and preservation methods. Modern cryopreservation prolongs the preservation time of homograft valved conduit, which makes it become the most important treatment at present, and is widely used in Ross and other operations. However, homograft valved conduit has limited biocompatibility and durability and lacks any additional growth capacity. Therefore, decellularized valved conduit has been proposed as an effective improved method, which can reduce immune response and calcification, and has potential growth ability. In addition, as a possible substitute, commercial xenograft valved conduit has certain advantages in clinical application, and tissue engineering artificial valved conduit needs to be further studied.

Pilot Study of the Biological Properties and Vascularization of 3D Printed Bilayer Skin Grafts.

The skin is the largest human organ, and defects in the skin with a diameter greater than 4 cm do not heal without treatment. Allogeneic skin transplantation has been used to allow wound healing, but many grafts do not survive after implantation, due to multiple complications in the procedure. In the present study, the vascularization of three-dimensional (3D) printed full-thickness skin grafts was investigated. Dermal-epithelial grafts were transplanted into a nude mouse model to evaluate integration with the host tissue and the extent of wound healing. To create microvessels in the skin grafts, a bilayer structure consisting of human dermal fibroblasts, keratinocytes, and microvascular endothelial cells was designed and fabricated using an extruded 3D printer. Human dermal fibroblasts and human microvascular endothelial cells were mixed with gelatin-sodium alginate composite hydrogel as the dermis, and human keratinocytes were mixed with gel as the epithelium. Confocal imaging allowed visualization of the location of the cells in the double-layer skin grafts. A full-thickness wound was created on the backs of nude mice and then covered with a double-layer skin graft. Various groups of mice were tested. Animals were euthanized and tissue samples collected after specified time points. Compared with the control group, wound contraction improved by approximately 10%. Histological analysis demonstrated that the new skin had an appearance similar to that of normal skin and with a significant degree of angiogenesis. The results of the immunohistochemical analysis demonstrated that the transplanted cells survived and participated in the healing process.