The paracrine effect of cobalt chloride on BMSCs during cognitive function rescue in the HIBD rat

Research hotspots and frontiers of preconditioning in cerebral ischemia: A bibliometric analysis

Background

Preconditioning is a promising strategy against ischemic brain injury, and numerous studies in vitro and in vivo have demonstrated its neuroprotective effects. However, at present there is no bibliometric analysis of preconditioning in cerebral ischemia. Therefore, a comprehensive overview of the current status, hot spots, and emerging trends in this research field is necessary.

Materials and methods

Studies on preconditioning in cerebral ischemia from January 1999-December 2022 were retrieved from the Web of Science Core Collection (WOSCC) database. CiteSpace was used for data mining and visual analysis.

Results

A total of 1738 papers on preconditioning in cerebral ischemia were included in the study. The annual publications showed an upwards and then downwards trend but currently remain high in terms of annual publications. The US was the leading country, followed by China, the most active country in recent years. Capital Medical University published the largest number of articles. Perez-Pinzon, Miguel A contributed the most publications, while KITAGAWA K was the most cited author. The focus of the study covered three areas: (1) relevant diseases and experimental models, (2) types of preconditioning and stimuli, and (3) mechanisms of ischemic tolerance. Remote ischemic preconditioning, preconditioning of mesenchymal stem cells (MSCs), and inflammation are the frontiers of research in this field.

Conclusion

Our study provides a visual and scientific overview of research on preconditioning in cerebral ischemia, providing valuable information and new directions for researchers.

Secretome as a Tool to Treat Neurological Conditions: Are We Ready?

Due to their characteristics, mesenchymal stem cells (MSCs) are considered a potential therapy for brain tissue injury or degeneration. Nevertheless, despite the promising results observed, there has been a growing interest in the use of cell-free therapies in regenerative medicine, such as the use of stem cell secretome. This review provides an in-depth compilation of data regarding the secretome composition, protocols used for its preparation, as well as existing information on the impact of secretome administration on various brain conditions, pointing out gaps and highlighting relevant findings. Moreover, due to the ability of MSCs to respond differently depending on their microenvironment, preconditioning of MSCs has been used to modulate their composition and, consequently, their therapeutic potential. The different strategies used to modulate the MSC secretome were also reviewed. Although secretome administration was effective in improving functional impairments, regeneration, neuroprotection, and reducing inflammation in brain tissue, a high variability in secretome preparation and administration was identified, compromising the transposition of preclinical data to clinical studies. Indeed, there are no reports of the use of secretome in clinical trials. Despite the existing limitations and lack of clinical data, secretome administration is a potential tool for the treatment of various diseases that impact the CNS.

Mesenchymal stem cell-seeded porous tantalum-based biomaterial: A promising choice for promoting bone regeneration

Porous tantalum-based biomaterial is a novel tissue engineering material widely used in repairing bone defects due to its corrosion resistance, low elastic modulus, high friction coefficient, and excellent biocompatibility. Bone marrow-derived mesenchymal stem cells (BMSCs), a type of pluripotent stem cell, can travel from their original ecological niche to bone injury sites, where they differentiate into osteoblasts and osteocytes. Multiple factors regulate the proliferation, migration, and differentiation of BMSCs. In recent years, the regulatory effects of porous tantalum on BMSCs have been widely studied. Hence, in this study, we reviewed the characteristics of porous tantalum-based biomaterials and the mechanism of action of their regulatory effects on BMSCs. Further, we discuss the feasibility of seeding BMSCs in porous tantalum-based biomaterials for use in tissue repair.

Mesenchymal Stromal Cells Preconditioning: A New Strategy to Improve Neuroprotective Properties

Neurological diseases represent one of the main causes of disability in human life. Consequently, investigating new strategies capable of improving the quality of life in neurological patients is necessary. For decades, researchers have been working to improve the efficacy and safety of mesenchymal stromal cells (MSCs) therapy based on MSCs’ regenerative and immunomodulatory properties and multilinear differentiation potential. Therefore, strategies such as MSCs preconditioning are useful to improve their application to restore damaged neuronal circuits following neurological insults. This review is focused on preconditioning MSCs therapy as a potential application to major neurological diseases. The aim of our work is to summarize both the in vitro and in vivo studies that demonstrate the efficacy of MSC preconditioning on neuronal regeneration and cell survival as a possible application to neurological damage.

[Effects of lentivirus-mediated RNA interference of HIF-1α and PTEN on oxygen-glucose deprivation injury in primary cultured rat neurons]

OBJECTIVE

To observe the effects of lentivirus-mediated RNA interference (RNAi) of hypoxia-inducible factor 1α (HIF-1α) and phosphatase and tensin homolog on chromosome ten (PTEN) on oxygen-glucose deprivation (OGD) injury in primary cultured rat neurons.

METHODS

Primary cultures of neonatal SD rat neurons were infected by lentiviral vectors carrying short hairpin RNA (shRNA) targeting HIF-1α or PTEN followed 4 days later by hypoxic exposure, and the control neurons were infected with the empty virus only with or without subsequent hypoxic exposure. Twenty-four hours after hypoxia, the interference efficiency was assessed with qRT-PCR, and lactate dehydrogenase (LDH) assay and AnnexinV-FITC/ PI assay were performed to detect neuronal damage and apoptosis. The expressions of the related proteins were determined with Western blotting.

RESULTS

Lentivirus-mediated RNAi effectively silenced the mRNA expression of the target genes. HIF-1α silencing obviously aggravated the hypoxia-induced damage and apoptosis of the neurons, enhanced the expression of PTEN protein and significantly lowered the expressions of p-PTEN, p-AKT, NR2A and VEGFa (P < 0.05). PTEN silencing significantly alleviated hypoxia-induced damage and apoptosis of the neurons and increased the cellular expressions of p-PTEN and p-AKT (P < 0.05) without obviously affecting the expressions of HIF-1α, NR2A or VEGFa (P>0.05).

CONCLUSION

An up-regulated expression of HIF-1α causes down-regulation of PTEN expression to protect primary cultured rat neurons against OGD injury.

Glibenclamide Attenuates Neuroinflammation and Promotes Neurological Recovery After Intracerebral Hemorrhage in Aged Rats

Intracerebral hemorrhage (ICH) is a common disease in the elderly population. Inflammation following ICH plays a detrimental role in secondary brain injury, which is associated with a poor prognosis of patients with ICH, and no efficient pharmacological preventions are available. Here, we investigated the effects of glibenclamide (GLC) on neuroinflammation in an autoblood-induced aged rat (18 months old) model of ICH. Rats were randomized into the sham, vehicle, and GLC groups. First, we investigated the expression level of sulfonylurea receptor 1 (Sur1) surrounding the hematoma after ICH. Then, neurological scores were calculated, and water maze tests, brain water content analysis, western blotting, and immunofluorescence assays were implemented to detect the neuroprotective effect of GLC. The expression of the Sur1-Trpm4 channel was significantly increased in the perihematomal tissue following ICH in aged rats. The GLC administration effectively reduced brain edema and improved neurofunction deficits following ICH. In addition, GLC increased the expression of brain-derived neurotrophic factors and decreased the expression of proinflammatory factors [tumor necrosis factor (TNF)-α,interleukin (IL)-1, and IL-6]. Moreover, GLC markedly reduced Ikappa-B (IκB) kinase (IKK) expression in microglia and nuclear factor (NF)-κB-P65 levels in perihematomal tissue. GLC ameliorated ICH-induced neuroinflammation and improved neurological outcomes in aged rats. In part, GLC may exert these effects by regulating the NF-κB signaling pathway through the Sur1-Trpm4 channel.

The effect of magnetic guiding BMSCs on hypoxic-ischemic brain damage via magnetic resonance imaging evaluation

Hypoxic-ischemic brain damage (HIBD) is a critical disease in pediatric neurosurgery with high mortality rate and frequently leads to neurological sequelae. The role of bone marrow mesenchymal stem cells (BMSCs) in neuroprotection has been recognized. However, using the imaging methods to dynamically assess the neuroprotective effects of BMSCs is rarely reported. In this study, BMSCs were isolated, cultured and identified. Flow cytometry assay had shown the specific surface molecular markers of BMSCs, which indicated that the cultivated cells were purified BMSCs. The results demonstrated that CD29 and CD90 were highly expressed, whilst CD45 and CD11b were negatively expressed. Further, BMSCs were transplanted into Sprague Dawley (SD) rats established HIBD via three ways, including lateral ventricle (LV) injection, tail vein (TV) injection, and LV injection with magnetic guiding. Magnetic resonance imaging (MRI) was used to monitor and assess the treatment effect of super paramagnetic iron oxide (SPIO)-labeled BMSCs. The mean kurtosis (MK) values from diffusion kurtosis imaging (DKI) exhibited the significant differences. It was found that the MK value of HIBD group increased compared with that in Sham. At the meantime, the MK values of LV + HIBD, TV + HIBD and Magnetic+LV + HIBD groups decreased compared with that in HIBD group. Among these, the MK value reduced most significantly in Magnetic+LV + HIBD group. MRI illustrated that the treatment effect of Magnetic+LV + HIBD group was best. In addition, HE staining and TUNEL assay measured the pathological changes and apoptosis of brain tissues, which further verified the MRI results. All data suggest that magnetic guiding BMSCs, a targeted delivery way, is a new strategic theory for HIBD treatment. The DKI technology of MRI can dynamically evaluate the neuroprotective effects of transplanted BMSCs in HIBD.

BMSCs protect against renal ischemia-reperfusion injury by secreting exosomes loaded with miR-199a-5p that target BIP to inhibit endoplasmic reticulum stress at the very early reperfusion stages

Bone marrow-derived mesenchymal stem cells (BMSCs) have been recently reported to play a variety of vital roles in organ and tissue damage repair, mainly via potent paracrine activity, including secreting extracellular vesicles, such as exosomes, that serve as mediators facilitating intercellular communication and reprogramming recipient cells by delivering their contents to target cells. However, the underlying mechanisms are diverse and complex, and the influencing characteristics have rarely been studied. Accordingly, we designed this study to explore the time dependence of the effects of exosomes derived from BMSCs (BMexos) on renal ischemia-reperfusion (I/R) injury and the underlying mechanisms associated with the reperfusion time. Impressively, our study is the first to find that BMexos protected against renal I/R injury in vitro and in vivo at the very early reperfusion stages, especially 4-8 h after reperfusion in vitro and 8-16 h after reperfusion in vivo. Interestingly, we simultaneously found that endoplasmic reticulum (ER) stress was significantly suppressed following the administration of BMexos in vitro and in vivo with a similar time dependence. Additionally, we discovered that miR-199a-5p, which was abundant in the BMSCs, was transferred into renal tubular epithelial cells (NRK-52E) in a time-dependent manner and significantly inhibited I/R-induced ER stress by targeting binding immunoglobulin protein (BIP). Cocultivation with miR-199a-5p-overexpressing BMSCs amplified the suppression of ER stress and further protected against I/R injury. However, coculture with miR-199a-5p-knockdown BMSCs obviously increased ER stress and reversed the BMexos-induced protection, and silencing BIP by small interfering RNA-1098 in NRK-52E inhibited these effects. This study provides evidence that administering BMexos at the very early reperfusion stages significantly protects against renal I/R injury, and ER stress is closely linked to this protection. These results suggest a novel therapeutic strategy during the very early reperfusion stages of renal I/R injury.-Wang, C., Zhu, G., He, W., Yin, H., Lin, F., Gou, X., Li, X. BMSCs protect against renal ischemia-reperfusion injury by secreting exosomes loaded with miR-199a-5p that target BIP to inhibit endoplasmic reticulum stress at the very early reperfusion stages.

HIF-1<alpha> Repression of PTEN Transcription Mediates Protective Effects of BMSCs on Neurons During Hypoxia

Neonatal hypoxic-ischemic brain damage (HIBD) is a cerebral hypoxic-ischemic disease caused by a variety of insults during the perinatal period, leading to varying degrees of cognitive dysfunction. Mesenchymal stem cells play an important role in functional recovery, but the mechanism is not yet clear. It has been reported that HIF-1<alpha> and PTEN are involved in the process of hypoxia-ischemia, but the specific roles that these proteins play remains to be understood. In this study, we performed oxygen glucose deprivation (OGD) or CoCl₂ preconditioning on hippocampal neurons to simulate a hypoxic environment in vitro, and then co-cultured them with BMSCs, to observe the effect of BMSCs and the role of HIF-1<alpha>. In addition, bpV, an inhibitor of PTEN was added to OGD neurons to determine the role of PTEN during hypoxia. We found that the levels of cell damage and apoptosis in OGD neurons decreased significantly after co-culture with BMSCs. Apoptosis was increased when HIF-1<alpha> was inhibited, but neurons remained protected when PTEN was suppressed. We further established that HIF-1<alpha> was enriched at the PTEN promoter both in BMSCs and hippocampal neurons, with increased enrichment under hypoxic conditions, leading to reduced transcription of PTEN. Our findings support the conclusion that CoCl₂ preconditioning of BMSCs can simulate hypoxic conditions and can protect OGD neurons, an effect that is mediated through activation of the HIF-1<alpha> system and repression of PTEN transcription.