Stem cells and vascular dementia: from basic science to the clinic

The role of the neurovascular unit in vascular cognitive impairment: Current evidence and future perspectives

Vascular cognitive impairment (VCI) is a progressive cognitive impairment caused by cerebrovascular disease or vascular risk factors. It is the second most common type of cognitive impairment after Alzheimer's disease. The pathogenesis of VCI is complex, and neurovascular unit destruction is one of its important mechanisms. The neurovascular unit (NVU) is responsible for combining blood flow with brain activity and includes endothelial cells, pericytes, astrocytes and many regulatory nerve terminals. The concept of an NVU emphasizes that interactions between different types of cells are essential for maintaining brain homeostasis. A stable NVU is the basis of normal brain function. Therefore, understanding the structure and function of the neurovascular unit and its role in VCI development is crucial for gaining insights into its pathogenesis. This article reviews the structure and function of the neurovascular unit and its contribution to VCI, providing valuable information for early diagnosis and prevention.

Transcutaneous Electrical Acupoint Stimulation Ameliorates Cognitive Function through PINK1/Parkin Mediated Mitophagy in VD Rats

In this study, we investigated whether transcutaneous electrical acupoint stimulation (TEAS) could improve cognitive function in VD rats by regulating PINK1/Parkin-mediated mitophagy. VD rat model was prepared by modified 2-vessel occlusion (2-VO) and randomly divided into four groups: Sham group (Sham), Model group (Model), TEAS group (TEAS), and TEAS + 3-MA group (T +3 -MA). In the T +3 -MA group, autophagy inhibitor (3-MA) was injected into the lateral ventricle. After modeling, Y maze (YM), new object recognition test (NORT), Morris water maze (MWM), immunofluorescence, and Western blot were used to observe the effects of TEAS on VD rats. Behavioral experiments revealed that TEAS effectively improved the learning and memory ability of VD rats. Immunofluorescence results showed that TEAS could upregulate LC3 expression. Western blot results showed that TEAS upregulated the expression of PINK1, Parkin, and LC3-II, and downregulated the expression of LC3-I and p62 in VD rats. T +3 -MA group shows the opposite trend to TEAS group. This study demonstrates that TEAS ameliorates cognitive function through PINK1/Parkin-mediated mitophagy in VD rats.

Human ESC-derived immunity- and matrix- regulatory cells ameliorated white matter damage and vascular cognitive impairment in rats subjected to chronic cerebral hypoperfusion

OBJECTIVES

This study investigated the ability of immunity- and matrix- regulatory cells (IMRCs) to improve cognitive function in a rat model of vascular cognitive impairment.

MATERIALS AND METHODS

A chronic cerebral hypoperfusion (CCH) model was established in rats via permanent bilateral occlusion of the common carotid arteries (two-vessel occlusion, 2VO). The rats then received intravenous injections of IMRCs or saline. A single injection of different doses of IMRCs (1 × 106  cells/rat, 2 × 106  cells/rat, or 4 × 106  cells/rat) was administered via tail vein 72 h after establishment of the model. To evaluate functional recovery, the rats were subjected to behavioural tests after 30 days of CCH. Imaging, western blotting, immunofluorescence staining, and quantitative real-time PCR were used to analyse neuroinflammation and white matter injury after 14 and 40 days of CCH. RNA sequencing (RNA-seq) was used to profile gene expression changes in copine 1 (CPNE1) in response to IMRCs treatment.

RESULTS

Intravenous injection of 4 × 106 IMRCs alleviated white matter damage and ameliorated cognitive deficits in rats subjected to CCH. Immunofluorescence staining suggested that activation of microglia and astrocytes was reduced, and RNA sequencing showed that CPNE1 expression was significantly elevated following treatment with IMRCs.

CONCLUSIONS

Intravenous injection of IMRCs protected against CCH-induced white matter injury and cognitive impairment inhibition of microglial activation and regulation of microglia polarization.

Ion channels in stem cells and their roles in stem cell biology and vascular diseases

Stem cell therapy may be a promising option for the treatment of vascular diseases. In recent years, significant progress has been made in stem cell research, especially in the mechanism of stem cell activation, homing and differentiation in vascular repair and reconstruction. Current research on stem cells focuses on protein expression and transcriptional networks. Ion channels are considered to be the basis for the generation of bioelectrical signals, which control the proliferation, differentiation and migration of various cell types. Although heterogeneity of multiple ion channels has been found in different types of stem cells, it is unclear whether the heterogeneous expression of ion channels is related to different cell subpopulations and/or different stages of the cell cycle. There is still a long way to go in clinical treatment by using the regulation of stem cell ion channels. In this review, we reviewed the main ion channels found on stem cells, their expression and function in stem cell proliferation, differentiation and migration, and the research status of stem cells' involvement in vascular diseases.

Genetic Constructs for the Control of Astrocytes' Activity

In the current review, we aim to discuss the principles and the perspectives of using the genetic constructs based on AAV vectors to regulate astrocytes’ activity. Practical applications of optogenetic approaches utilizing different genetically encoded opsins to control astroglia activity were evaluated. The diversity of astrocytic cell-types complicates the rational design of an ideal viral vector for particular experimental goals. Therefore, efficient and sufficient targeting of astrocytes is a multiparametric process that requires a combination of specific AAV serotypes naturally predisposed to transduce astroglia with astrocyte-specific promoters in the AAV cassette. Inadequate combinations may result in off-target neuronal transduction to different degrees. Potentially, these constraints may be bypassed with the latest strategies of generating novel synthetic AAV serotypes with specified properties by rational engineering of AAV capsids or using directed evolution approach by searching within a more specific promoter or its replacement with the unique enhancer sequences characterized using modern molecular techniques (ChIP-seq, scATAC-seq, snATAC-seq) to drive the selective transgene expression in the target population of cells or desired brain regions. Realizing these strategies to restrict expression and to efficiently target astrocytic populations in specific brain regions or across the brain has great potential to enable future studies.

Exploring the Potential of Mesenchymal Stem Cell-Based Therapy in Mouse Models of Vascular Cognitive Impairment

Closely linked to Alzheimer’s disease (AD), the pathological spectrum of vascular cognitive impairment (VCI) is known to be wide and complex. Considering that multiple instead of a single targeting approach is considered a treatment option for such complicated diseases, the multifaceted aspects of mesenchymal stem cells (MSCs) make them a suitable candidate to tackle the heterogeneity of VCI. MSCs were delivered via the intracerebroventricular (ICV) route in mice that were subjected to VCI by carotid artery stenosis. VCI was induced in C57BL6/J mice wild type (C57VCI) mice by applying a combination of ameroid constrictors and microcoils, while ameroid constrictors alone were bilaterally applied to 5xFAD (transgenic AD mouse model) mice (5xVCI). Compared to the controls (minimal essential medium (MEM)-injected C57VCI mice), changes in spatial working memory were not noted in the MSC-injected C57VCI mice, and unexpectedly, the mortality rate was higher. In contrast, compared to the MEM-injected 5xVCI mice, mortality was not observed, and the spatial working memory was also improved in MSC-injected 5xVCI mice. Disease progression of the VCI-induced mice seems to be affected by the method of carotid artery stenosis and due to this heterogeneity, various factors must be considered to maximize the therapeutic benefits exerted by MSCs. Factors, such as the optimal MSC injection time point, cell concentration, sacrifice time point, and immunogenicity of the transplanted cells, must all be adequately addressed so that MSCs can be appropriately and effectively used as a treatment option for VCI.