Elevated bone resorption and diminished bone formation have been recognized as the primary features of glucocorticoid-associated skeletal disorders. However, the direct effects of excess glucocorticoids on bone turnover remain unclear. Here, we explored the outcomes of exogenous glucocorticoid treatment on bone loss and delayed fracture healing in mice and found that reduced bone turnover was a dominant feature, resulting in a net loss of bone mass. The primary effect of glucocorticoids on osteogenic differentiation was not inhibitory; instead, they cooperated with macrophages to facilitate osteogenesis. Impaired local nutrient status — notably, obstructed fatty acid transportation — was a key factor contributing to glucocorticoid-induced impairment of bone turnover in vivo. Furthermore, fatty acid oxidation in macrophages fueled the ability of glucocorticoid-liganded receptors to enter the nucleus and then promoted the expression of BMP2 , a key cytokine that facilitates osteogenesis. Metabolic reprogramming by localized fatty acid delivery partly rescued glucocorticoid-induced pathology by restoring a healthier immune-metabolic milieu. These data provide insights into the multifactorial metabolic mechanisms by which glucocorticoids generate skeletal disorders, thus suggesting possible therapeutic avenues.

With the rapid development of single‐cell sequencing technology, the Langendorff perfusion system has emerged as a common approach to decompose cardiac tissue and obtain living cardiomyocytes to study cardiovascular disease with the mechanism of cardiomyocyte biology. However, the traditional Langendorff perfusion system is difficult to master, and further, the viability and purity of cardiomyocytes are frequently unable to meet sequencing requirements due to complicated devices and manipulate processes. Here, we provide an optimized Langendorff perfusion system with a simplified and standardized operating protocol which utilizes gravity as the perfusion pressure, includes a novel method for bubbles removing and standardizes the criteria for termination of digestion. We obtained stable cardiomyocyte with high viability and purity after multiple natural gravity sedimentation. The combination of the optimized Langendorff perfusion system and the multiple natural gravity sedimentation provides a stable system for isolating adult mouse heart, which will provide higher‐quality cardiomyocytes for further experiments.

Background: Dilated cardiomyopathy (DCM) is one of the most frequent causes of heart failure and heart transplantation (HTx). The genetic basis of DCM among patients undergoing HTx remains to be further studied. This study aimed to characterize the genetic basis of DCM HTx in the Chinese population. Methods: In total, 208 unrelated DCM patients who underwent HTx at Fuwai Hospital between June 2004 and June 2017 were included in this study. Whole-exome sequencing (WES) was performed for all patients. Gene burden analysis, variant classification, and genotype–phenotype correlation analysis were subsequently performed. Results: After completing the bioinformatics analysis, gene burden analysis suggested that titin (TTN), filamin C (FLNC) and lamin A/C (LMNA) were significantly enriched with rare protein-altering variants. The frequencies of TTN and FLNC truncating variants in our cohort were 18.8% and 8.7%, respectively. Among the 165 rare variants in high evidence DCM-related genes, 27 (16.4%) and 59 (35.8%) were interpreted as pathogenic (P) and likely pathogenic (LP), respectively. In addition, 41 (47.7%) and 16 (18.6%) of these 86 P/LP variants are located in TTN and FLNC, respectively. The FLNC group contained more patients with NYHA class IV than the P/LP-negative group (FLNC, 16/18 vs. P/LP-negative, 81/123, P = 0.049). Conclusions: Based on WES, we provided a primary genetic spectrum of DCM patients undergoing HTx in the Chinese population. TTN and FLNC harbour the most P/LP variants. FLNC truncation may lead to severe clinical symptoms in DCM patients.

Persistent truncus arteriosus (PTA) is an uncommon and complex congenital cardiac malformation accounting for about 1.2% of all congenital heart diseases (CHDs), which is caused by a deficiency in the embryonic heart outflow tract’s (OFT) septation and remodeling. PDGFRα and PDGFRβ double knockout (DKO) in cardiac neural crest cells (CNCCs) has been reported to cause PTA, but the underlying mechanisms remain unclear. Here, we constructed a PTA mouse model with PDGFRα and PDGFRβ double knockout in Pax3⁺ CNCCs and described the condensation failure into OFT septum of CNCC-derived cells due to disturbance of cell polarity in the DKO group. In addition, we further explored the mechanism with single-cell RNA sequencing. We found that two main cell differentiation trajectories into vascular smooth muscle cells (VSMCs) from cardiomyocytes (CMs) and mesenchymal cells (MSs), respectively, were interrupted in the DKO group. The process of CM differentiation into VSMC stagnated in a transitional CM I-like state, which contributed to the failure of OFT remodeling and muscular septum formation. On the other hand, a Penk⁺ transitional MS II cluster closely related to cell condensation into the OFT septum disappeared, which led to the OFT’s septation absence directly. In conclusion, the disturbance of CNCC-derived cells caused by PDGFRα and PDGFRβ knockout can lead to the OFT septation disorder and the occurrence of PTA.

Postoperative delirium (POD) is a frequent neuropsychiatric complication after cardiac surgery, yet the biological basis of individual susceptibility remains unclear. In this prospective cohort study, 317 adults undergoing elective on-pump cardiac surgery were enrolled and followed for POD during the first 7 postoperative days. Thirty patients who developed POD were then matched 1:1 with 30 non-POD controls by age, sex, and primary diagnosis for multi-omic analyses. Preoperative fecal samples were collected from the first bowel movement after admission and before prophylactic antibiotic administration, and postoperative fecal samples were collected from the first postoperative bowel movement. Paired fecal samples underwent shotgun metagenomic sequencing, and perioperative serum samples underwent untargeted metabolomic profiling. Preoperatively, α- and β-diversity were comparable between groups, but patients who subsequently developed POD exhibited a less connected and less integrated microbial network structure. Postoperatively, gut microbial composition differed significantly between groups (PERMANOVA R² = 0.053, P < 0.001). Metagenomic profiling identified 35 differentially abundant species and 16 differentially enriched KEGG level 3 pathways, with POD-associated features showing inferred functional shifts toward amino-acid catabolism, including branched-chain amino acid (BCAA)-related pathways. Untargeted metabolomics demonstrated marked perioperative remodeling in both groups, but POD was associated with a 27-metabolite panel characterized predominantly by lower postoperative levels or impaired recovery, with pathway enrichment converging on valine, leucine, and isoleucine metabolism. Integrative analyses further linked POD-associated microbial taxa with amino-acid catabolic pathways and lower levels of BCAA-related serum metabolites. These findings suggest that POD is associated with preoperative alterations in microbial network organization and a postoperative microbiome-metabolome disturbance pattern centered on amino-acid metabolism, particularly the BCAA axis.

Background To understand the relationship between myocardial contractility and external stimuli, detecting ex vivo myocardial contractility is necessary. Methods We elaborated a method for contractility detection of isolated C57 mouse papillary muscle using Myostation-Intact system under different frequencies, voltages, and calcium concentrations. Results The results indicated that the basal contractility of the papillary muscle was 0.27 +/- 0.03 mN at 10 V, 500-ms pulse duration, and 1 Hz. From 0.1 to 1.0 Hz, contractility decreased with an increase in frequency (0.45 +/- 0.11-0.10 +/- 0.02 mN). The voltage-initiated muscle contractility varied from 3 to 6 V, and the contractility gradually increased as the voltage increased from 6 to 10 V (0.14 +/- 0.02-0.28 +/- 0.03 mN). Moreover, the muscle contractility increased when the calcium concentration was increased from 1.5 to 3 mM (0.45 +/- 0.17-1.11 +/- 0.05 mN); however, the contractility stopped increasing even when the concentration was increased to 7.5 mM (1.02 +/- 0.23 mN). Conclusions Our method guaranteed the survivability of papillary muscle ex vivo and provided instructions for Myostation-Intact users for isolated muscle contractility investigations.