Myocardial infarction (MI) results in cardiomyocyte necrosis and conductive system damage, leading to sudden cardiac death and heart failure. Studies have shown that conductive biomaterials can restore cardiac conduction, but cannot facilitate tissue regeneration. This study aims to add regenerative capabilities to the conductive biomaterial by incorporating human endometrial mesenchymal stem cell (hEMSC)‐derived exosomes (hEMSC‐Exo) into poly‐pyrrole‐chitosan (PPY‐CHI), to yield an injectable hydrogel that can effectively treat MI. In vitro, PPY‐CHI/hEMSC‐Exo, compared to untreated controls, PPY‐CHI, or hEMSC‐Exo alone, alleviates H₂O₂‐induced apoptosis and promotes tubule formation, while in vivo, PPY‐CHI/hEMSC‐Exo improves post‐MI cardiac functioning, along with counteracting against ventricular remodeling and fibrosis. All these activities are facilitated via increased epidermal growth factor (EGF)/phosphoinositide 3‐kinase (PI3K)/AKT signaling. Furthermore, the conductive properties of PPY‐CHI/hEMSC‐Exo are able to resynchronize cardiac electrical transmission to alleviate arrythmia. Overall, PPY‐CHI/hEMSC‐Exo synergistically combines the cardiac regenerative capabilities of hEMSC‐Exo with the conductive properties of PPY‐CHI to improve cardiac functioning, via promoting angiogenesis and inhibiting apoptosis, as well as resynchronizing electrical conduction, to ultimately enable more effective MI treatment. Therefore, incorporating exosomes into a conductive hydrogel provides dual benefits in terms of maintaining conductivity, along with facilitating long‐term exosome release and sustained application of their beneficial effects.

The therapeutic potential of autologous stem cell transplantation for heart repair diminishes in the elderly due to stem cell aging. Rejuvenating aged stem cells to enhance their protective effects on injured cardiomyocytes is crucial for aging patients with heart failure. In this study, we aimed to investigate whether NDNF over-expression improves the protective effect of aged stem cells for injured cardiomyocytes and explore the underlying mechanism. Human bone marrow was collected from both young and old patients, and BMSCs were cultured. Lentivirus expression vectors carrying NDNF genes were used to transfect aged BMSCs. Fatal hypoxia-induced injury in H9C2 cells served as an in vitro ischemia model. The conditioned medium from different BMSC groups was applied to assess the beneficial effects on hypoxia-induced damage in myocardial H9C2 cells. Results revealed that the conditioned medium of NDNF over-expressed old BMSCs increased H9C2 cell viability and reduced oxidative stress and apoptosis levels under fatal hypoxia. NDNF over-expressed old BMSCs exhibited an anti-apoptotic role by up-regulating the anti-apoptotic gene Bcl-2 and down-regulating the pro-apoptotic genes Bax. Additionally, the protective effects were mediated through the elevation of phosphorylated AKT. Our data support the promise of NDNF as a potential target to enhance the protective effects of autologous aged BMSCs on ischemic cardiomyocytes and then improve the curative effects of stem cell for ischemic heart injury in aged patients.

Objectives. The aim of this study was to evaluate the effects of bone marrow stromal stem cells (BMSCs) on renal ischemia-reperfusion injury (RIRI) and dynamically monitor engrafted BMSCs in vivo for the early prediction of their therapeutic effects in a rat model. Methods. A rat model of RIRI was prepared by clamping the left renal artery for 45 min. One week after renal artery clamping, 2 × 10⁶ superparamagnetic iron oxide- (SPIO-) labeled BMSCs were injected into the renal artery. Next, MR imaging of the kidneys was performed on days 1, 7, 14, and 21 after cell transplantation. On day 21, after transplantation, serum creatinine (Scr) and urea nitrogen (BUN) levels were assessed, and HE staining and TUNEL assay were also performed. Results. The body weight growth rates in the SPIO-BMSC group were significantly higher than those in the PBS group (P < 0.05), and the Scr and BUN levels were also significantly lower than those in the PBS group (P < 0.05). HE staining showed that the degree of degeneration and vacuole-like changes in the renal tubular epithelial cells in the SPIO-BMSC group was significantly better than that observed in the PBS group. The TUNEL assay showed that the number of apoptotic renal tubular epithelial cells in the SPIO-BMSC group was significantly lower than that in the PBS group. The T2 value of the renal lesion was the highest on day 1 after cell transplantation, and it gradually decreased with time in both the PBS and SPIO-BMSC groups but was always the lowest in the SPIO-BMSC group. Conclusion. SPIO-labeled BMSC transplantation can significantly promote the recovery of RIRI and noninvasive dynamic monitoring of engrafted cells and can also be performed simultaneously with MRI in vivo for the early prediction of therapeutic effects.

To investigate the value of applying habitat imaging (HI) radiomics on venous-phase computed tomography (CT) images from laryngeal squamous cell carcinoma (LSCC) patients, as part of a nomogram to predict Ki-67 positivity, an indicator of poorer LSCC prognoses. Clinical and CT imaging data from 128 LSCC patients, divided into training (89) and testing (39) groups, were analyzed. Conventional and HI radiomics features were extracted from enhanced venous phase images, either from the entire tumor (conventional) or 3 sub-regions (HI). Radiomics models were established, based on 5 machine learning algorithms, while clinical characteristics were analyzed by both uni- and multi-variate logistic regression analyses for their associations with Ki-67 positivity. Afterwards, a predictive nomogram was constructed by combining clinical characteristics, conventional radiomics, and HI radiomics. The only clinical characteristic strongly predictive for Ki-67-positivity is the degree of differentiation (low/medium vs. high). Additionally, HI radiomics was significantly more accurate than conventional for predicting Ki-67-positivity. The most accurate model, though, was the predictive nomogram, with areas under the curve of 0.945 (training) and 0.871 (testing), which was significantly higher than for clinical characteristics, conventional radiomics and HI radiomics models alone; it also had the highest net benefit, and thus greatest clinical utility under decision curve analysis. HI radiomics features were more accurate for predicting Ki-67-positivity in LSCC than conventional radiomics. However, the combination of those features with conventional radiomics and the degree of differentiation in a predictive nomogram yields the most accurate model for Ki-67-positivity.