Single-cell RNA-seq reveals cellular heterogeneity from deep fascia in patients with acute compartment syndrome

Abstract

IntroductionHigh stress in the compartment surrounded by the deep fascia can cause acute compartment syndrome (ACS) that may result in necrosis of the limbs. The study aims to investigate the cellular heterogeneity of the deep fascia in ACS patients by single-cell RNA sequencing (scRNA-seq).MethodsWe collected deep fascia samples from patients with ACS (high-stress group, HG, n=3) and patients receiving thigh amputation due to osteosarcoma (normal-stress group, NG, n=3). We utilized ultrasound and scanning electron microscopy to observe the morphologic change of the deep fascia, used multiplex staining and multispectral imaging to explore immune cell infiltration, and applied scRNA-seq to investigate the cellular heterogeneity of the deep fascia and to identify differentially expressed genes.ResultsNotably, we identified GZMK+interferon-act CD4 central memory T cells as a specific high-stress compartment subcluster expressing interferon-related genes. Additionally, the changes in the proportions of inflammation-related subclusters, such as the increased proportion of M2 macrophages and decreased proportion of M1 macrophages, may play crucial roles in the balance of pro-inflammatory and anti-inflammatory in the development of ACS. Furthermore, we found that heat shock protein genes were highly expressed but metal ion-related genes (S100 family and metallothionein family) were down-regulated in various subpopulations under high stress.ConclusionsWe identified a high stress-specific subcluster and variations in immune cells and fibroblast subclusters, as well as their differentially expressed genes, in ACS patients. Our findings reveal the functions of the deep fascia in the pathophysiology of ACS, providing new approaches for its treatment and prevention.

Olink proteomics analysis uncovers the landscape of inflammation-related proteins in patients with acute compartment syndrome

“…However, the relationship between CCL23 and ACS remains obscure. We only found that the level of CCL23 was significantly higher in the AG than in the FG, which was partially consistent with our previous conclusions that there was a significant variation in monocytes and macrophages in patients with ACS (19). Furthermore, we identified 35.75 pg/ml as the cutoff value of CCL23 for predicting ACS in tibial fracture patients.…”

“…IL6 contributes to the regulation of macrophages toward M1 macrophage polarization, whereas CSF-1 and HGF stimulate macrophages toward M2 macrophage polarization. Our previous single-cell RNA analysis showed that the proportion of macrophages has undergone significant changes, especially M1 macrophages and M2 macrophages, indicating that the balance of M1 macrophages and M2 macrophages may affect the development of ACS (19). We can assume that CSF-1, IL6, and HGF are involved in the development of ACS patients.…”

Proteomics analysis of deep fascia in acute compartment syndrome

“…In our previous study, we found that collagen fibers in the deep fascia were broken in the early stage of ACS, which may be a result of the deep fascia self-regulation and the release of intracompartmental pressure [ 37 ]. In the present study, we found further that the expression of PXDN (promoting the function of fibroblasts [ 38 ]) and CD74 (enhancing the proliferation process of fibroblasts [ 39 ]) were increased in the deep fascia tissue of patients with blister ( p all <0.05).…”

Compartment syndrome – a complex and insidious medical problem

“…In addition, recent studies at the molecular level have identified some differences in immune cells in ACS patients. In the CD4 cell group, the GZMK+IFN-act subtype and high expression of genes responsible for the production of interferon and heat shock proteins were found [34]. This gives hope for the discovery of targeted cell-based treatments for ACS in the future.…”