Rationale: The COVID-19 cases increased very fast in January and February 2020. The mortality among critically ill patients, especially the elder ones, is relatively high. Considering many patients died of severe inflammation response, it is urgent to develop effective therapeutic strategies for these patients. The human umbilical cord mesenchymal stem cells (hUCMSCs) have shown good capabilities to modulate the immune response and repair the injured tissue. Therefore, investigating the potential of hUCMSCs to the treatment of COVID-19 critically ill patients is necessary. Patient concerns: A 65-year-old woman felt fatigued and had a fever with body temperature of 38.2^°C, coughed up white foaming sputum. After 1 day, she had chest tightness with SPO₂ of 81%, and blood pressure of 160/91 mm Hg. Diagnose: According to the guideline for the diagnosis and treatment of 2019 novel coronavirus infected pneumonia (Trial 4th Edition), COVID-19 was diagnosed, based on the real-time RT-PCR test of SARS-CoV-2. Interventions: After regular treatment for 12 days, the inflammation symptom of the patient was still very severe and the potential side effects of corticosteroid were observed. Then, allogenic hUCMSCs were given 3 times (5 × 10⁷ cells each time) with a 3-day interval, together with thymosin α1 and antibiotics daily injection. Outcomes: After these treatments, most of the laboratory indexes and CT images showed remission of the inflammation symptom. The patient was subsequently transferred out of ICU, and the throat swabs test reported negative 4 days later. Lessons: These results indicated the clinical outcome and good tolerance of allogenic hUCMSCs transfer.

Background: The transfer of mitochondria from healthy mesenchymal stem cells (MSCs) to injured MSCs has been shown to have potential therapeutic benefits for neural cell post-ischemic stroke. Specifically, functional mitochondria can perform their normal functions after being internalized by stressed cells, leading to host cell survival. However, while this approach shows promise, there is still a lack of understanding regarding which neural cells can internalize functional mitochondria and the regulatory mechanisms involved. To address this gap, we investigated the ability of different neural cells to internalize exogenous functional mitochondria extracted from MSCs.Methods: Functional mitochondria (F-Mito) isolated from umbilical cord derived-MSCs (UCMSCs) were labeled with lentivirus of HBLV-mito-dsred-Null-PURO vector. The ability of stressed cells to internalize F-Mito was analyzed using a mouse (C57BL/6 J) middle cerebral artery occlusion (MCAO) model and an oxygen-glucose deprivation/reoxygenation (OGD/R) cell model. The cell viability was measured by CCK-8 kit. Time-course of intracellular ROS levels in stressed cells were analyzed by DCFH-DA staining after OGD/R and F-Mito treatment. MitoSOX, Mitotracker and WGA labeling were used to assess the relationship between ROS levels and the uptake of F-Mito at the single-cell level. Pharmacological modulation of ROS was performed using acetylcysteine (ROS inhibitor).Results: Our findings demonstrate that neurons and endothelial cells are more effective at internalizing mitochondria than astrocytes, both in vitro and in vivo, using an ischemia-reperfusion model. Additionally, internalized F-Mito decreases host cell reactive oxygen species (ROS) levels and rescues survival. Importantly, we found that the ROS response in stressed cells after ischemia is a crucial determinant in positively mediating the internalization of F-Mito by host cells, and inhibiting the generation of ROS chemicals in host cells may decrease the internalization of F-Mito. These results offer insight into how exogenous mitochondria rescue neural cells via ROS response in an ischemic stroke model. Overall, our study provides solid evidence for the translational application of MSC-derived mitochondria as a promising treatment for ischemic stroke.

Bone damage is a condition that affects the quality of life of patients. Mesenchymal stem cells (MSCs) are important for bone repair. Osteoking is a natural compound in traditional Chinese Medicine used to treat bone diseases; however, the effect of Osteoking on the differentiation of MSCs has not been reported. In this study, we aimed to investigate the effect of Osteoking on the osteogenic and adipogenic differentiation potential of rat bone marrow mesenchymal stem cells (rbMSCs). The effects of Osteoking on the proliferation and differentiation of rbMSCs were investigated. Different concentrations of Osteoking were prepared, and its cytotoxicity was evaluated by CCK-8 assay. The expression of osteogenic and adipogenic genes were determined, and several staining methods were used to reveal the osteogenic and adipogenic differentiation potential of rbMSCs. Our results show that appropriate concentrations of Osteoking can enhance osteogenic differentiation of rbMSCs and reduce adipogenic differentiation without any effect on proliferation. This may be related to the changes in related gene expression. Osteoking enhances osteogenic differentiation and inhibits adipogenic differentiation of rbMSCs. Therefore, Osteoking may have a therapeutic potential for treating bone disease caused by changes in differentiation function of MSCs.

Osteoporosis (OP) treatment has always been challenging for elderly menopausal females. An animal model with a closer genetic association to human OP is essential for treatment research. Given its close genetic association to primates, the tree shrew is a suitable candidate for meeting the requirements for such an animal model. In the present study, a tree shrew OP model induced by ovariectomy (OVX), was established. Evaluation by multiple analysis methods, including blood biochemical indicators, uterus coefficients, micro‑computed tomography analysis, histochemical analysis and scanning electron microscopic observation indicated that OVX was an appropriate method to establish the OP model in tree shrews. In addition, the biomolecular characteristics of OVX‑induced osteoporosis were also assessed by transcriptome sequencing and bioinformatics analysis. The present study provides the methods used to confirm the successful establishment of the OP model in tree shrew, and suggests that the OP model is appropriate for human OP research.

Bone diseases profoundly affect patients, particularly the elderly, leading to severe health complications and disabilities. Osteoblasts play a crucial role in bone formation and are ideal candidates for treating bone diseases and engineering living materials. However, the stem and progenitor cells that give rise to osteoblasts, as well as osteoblasts themselves, exhibit dysfunction with aging. Although chemical reprogramming of fibroblasts into osteoblasts has been achieved, effective cell-based therapies or living materials have not been established in clinical practice. Here, we present a method to engineer fibroblasts through small molecule reprogramming and spheronization, achieving functional osteoblastic materials across all age groups. By primarily targeting the WNT signaling pathway and modularizing small molecules based on their effects on stage-specific genes, we optimized the temporal regulation of small molecules during reprogramming, acquiring a large number of healthy induced osteoblasts (iOBs). These iOBs with traits of functional native osteoblasts are ideal for forming transplantable tissue spheroids. As innovative living materials, the iOB spheroids (iOB-Sps) have demonstrated improved survival, significant self-bone formation, reduced ROS levels in the defect microenvironment, and accelerated endogenous osteogenesis and angiogenesis in vivo, promoting effective healing of bone defects. These material-free iOB-Sps function as self-scaffolding building blocks for biofunctional constructs, offering a promising avenue for clinical autologous bone defect repair, especially for the elderly.

Idiopathic pulmonary fibrosis (IPF) is an age-related disease severely affecting life quality with its prevalence rising as the population ages, yet there is still no effective treatment available. Cell therapy has emerged as a promising option for IPF, however, the absence of mature and stable animal models for IPF immunodeficiency hampers preclinical evaluations of human cell therapies, primarily due to rapid immune clearance of administered cells. This study aims to establish a reliable pulmonary fibrosis (PF) model in immunodeficient mice that supports autologous cell therapy and to investigate underlying mechanism. We utilized thirty 5-week-old male NOD/SCID mice, categorizing them into three age groups: 12weeks, 32 weeks and 43 weeks, with 6 mice euthanized randomly from each cohort for lung tissue analysis. We assessed fibrosis using HE staining, Masson’s trichrome staining, α-SMA immunohistochemistry and hydroxyproline content measurement. Further, β-galactosidase staining and gene expression analysis of MMP9, TGF-β1, TNF-α, IL-1β, IL-6, IL-8, SOD1, SOD2, NRF2, SIRT1, and SIRT3 were performed. ELISA was employed to quantify protein levels of TNF-α, TGF-β1, and IL-8. When comparing lung tissues from 32-week-old and 43-week-old mice to those from 12-week-old mice, we noted a marked increase in inflammatory infiltration, fibrosis severity, and hydroxyproline content, alongside elevated expression levels of α-SMA and MMP9. Notably, the degree of fibrosis intensified with age. Additionally, β-galactosidase staining became more pronounced in older mice. Quantitative PCR analyses revealed age-related, increases in the expression of senescence markers (GLB1, P16, P21), and proinflammatory genes (TGF-β1, TNF-α, IL-1β, IL-6, and IL-8). Conversely, the expression of anti-oxidative stress-related genes (SOD1, SOD2, NRF2, SIRT1, and SIRT3) declined, showing statistically significant differences (*P < 0.05, **P < 0.01, ***P < 0.001). ELISA results corroborated these findings, indicating a progressive rise in the protein levels of TGF-β1, TNF-α, and IL-8 as the mice aged. The findings suggest that NOD/SCID mice aged 32 weeks and 43 weeks effectively model pulmonary fibrosis in an elderly context, with the disease pathogenesis likely driven by age-associated inflammation and oxidative stress.