Transplantation of bone-marrow-derived mesenchymal stem cells into a murine model of immune thrombocytopenia

Magnetic resonance imaging study of normal cranial bone marrow conversion at high altitude

BACKGROUND

To use conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) to investigate the effects of long-term hypoxia on cranial bone marrow conversion in healthy people at high altitudes.

METHODS

A total of 1,130 individuals were selected from altitudinal areas of 2,000-3,000, 3,100-4,000, and >4,100 m. Each altitude range was divided into 5 age groups: 0-5, 6-14, 15-29, 30-49, and ≥50 years. Firstly, cranial bone marrow typing of the participants in each altitude range was performed on sagittal T1-weighted images (T1WI) according to the average diploe thickness and signal intensity of the normal skull, and the relationship between bone marrow conversion and age was analyzed. Secondly, the apparent diffusion coefficient (ADC) values of the frontal bone, parietal bone, occipital bone, and temporal bone were measured in the DWI post-processing workstation and statistical methods were used to analyze whether different altitudinal gradients and long-term hypoxic environment had any effect on cranial bone marrow conversion.

RESULTS

There was a positive correlation between bone marrow type and age in the healthy populations at all 3 levels of altitude (P<0.05). The average thickness of the cranial diploe also positively correlated with age (P<0.05); in the age ranges of 30-49 and ≥50 years, the ADC values of the occipital and temporal bone marrow positively correlated with increasing altitude (P<0.05).

CONCLUSIONS

The cranial bone marrow of normal people at high altitudes changes from Type I to Type IV with increasing age and under the influence of long-term chronic hypoxia. The bone marrow of the occipital and temporal bones of healthy people aged 30-49 and ≥50 years showed erythromedularization during the process of Type III and IV bone marrow conversion.

The Mechanistic Effects and Clinical Applications of Various Derived Mesenchymal Stem Cells in Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by persistent thrombocytopenia resulting from increased platelet destruction and a loss of autoimmune tolerance. The pathogenesis of ITP is highly complex. Although ITP may be effectively controlled with currently available medications in some patients, a subset of cases remain refractory. The application of mesenchymal stem cells (MSCs) for human hematopoietic stem cell transplantation has increasingly demonstrated that MSCs modulate innate or adaptive immunity, thus resulting in a tolerant microenvironment. Functional defects and immunomodulatory disorders have been observed after the use of bone marrow mesenchymal stem cells (BM-MSCs) from patients with ITP. Here, we summarize the underlying mechanisms and clinical applications of various derived MSCs for ITP treatment, focusing on the main mechanisms underlying the functional defects and immune dysfunction of BM-MSCs from patients with ITP. Functional effects associated with the activation of the p53 pathway include decreased activity of the phosphatidylinositol 3 kinase/Akt pathway and activation of the TNFAIP3/NF-κB/SMAD7 pathway. Immune dysfunction appears to be associated with an impaired ability of BM-MSCs to induce various types of immune cells in ITP. At present, research focusing on MSCs in ITP remains in preliminary stages. The application of autologous or exogenous MSCs in the clinical treatment of ITP has been attempted in only a small case study and must be validated in larger-scale clinical trials.

The mechanism of TDP-43 gene expression on inflammatory factors and the JNK and p38 MAPK signalling pathways in ischaemic hypoxic stress dependence

In this study, the mechanism of TDP-43 gene expression on inflammatory factors and Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) signalling pathways in ischaemic hypoxic stress dependence was investigated. Sixty SD rats were selected and divided into the control group, the osteoarthritis (OA) model group, and the TDP-43-mMSCs+OA group. In the OA model group and the TDP-43-mMSCs+OA group, OA was established by collagenase injection. Western blotting assays were used to detect the expression of TDP-43 in cartilage tissues of each rat. The secretion of tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the serum of rats was determined by enzyme-linked immunosorbent assay (ELISA). The formation of cytoplasmic stress granules (SGs) and the expression of receptor for activated c-kinase 1 (RACK1) were detected by Western blotting assays in each group of rats. The expression of MTK1 and MAPKKK phosphorylation and changes in the JNK and p38 MAPK signalling pathways were detected by Western blotting assays. Compared with the control group, the expression of TDP-43 in the cartilage tissue of rats in the OA model group was significantly decreased. The expression of TDP-43 in the cartilage tissue of rats in the TDP-43-mMSCs+OA group was significantly higher than that of the control group and the OA model group, which indicates that TDP-43-mMSC transplantation was successful. Enzyme-linked immunosorbent assay results showed that the plasma TNF-α and IL-1β levels in the OA model group were significantly increased (P < 0.01) when compared with the control group. However, the secretion of TNF-α and IL-1β in the serum of the TDP-43-mMSCs+OA group was significantly lower than that of the model group (P < 0.01) but still higher than the control group. This indicates that overexpression of TDP-43 reduces the inflammatory response induced by OA. Western blotting assays showed that the amount of cytoplasmic SGs in the cartilage tissue of rats in the OA model group was significantly decreased when compared with the control group. The amount of SGs in the cartilage of rats in the TDP-43-mMSCs+OA group was significantly higher than that of the model group. The expression of RACK1 in the cartilage tissue of rats in the OA model group was significantly higher than that of the control group. Overexpression of the TDP-43 gene can interfere with the secretion of inflammatory factors and inhibit the activation of the JNK and p38 MAPK signalling pathways by ischaemic hypoxia stress. Thus, the molecular mechanism of chondrocytopathic lesions was reversed, which provided a new theoretical basis for the treatment of OA.