cognitive-function-upper-limb-rehabilitation-training-post-stroke

Cognitive Function and Upper Limb Rehabilitation Training Post-Stroke Using a Digital Occupational Training System

Stroke rehabilitation often requires frequent and intensive therapy to improve functional recovery. Virtual reality (VR) technology has shown the ...

enhancing-upper-limb-function-motor-skills-post-stroke-through-an

Enhancing Upper Limb Function and Motor Skills Post-Stroke Through an Upper Limb Rehabilitation Robot

Cerebrovascular accidents, commonly known as strokes, represent a prevalent neurological event leading to significant upper limb disabilities, thereby ...

Wenzhou Medical University

Taizhou Hospital Affiliated to Wenzhou Medical University

Serum testosterone (TS) levels decrease with aging in both humans and rodents. Using the rat as a model system, it was found that age-related reductions in serum TS were not due to loss of Leydig cells, but rather to the reduced ability of the Leydig cells to produce TS in response to luteinizing hormone (LH). Detailed analyses of the steroidogenic pathway have suggested that two defects along the pathway, LH-stimulated cAMP production and cholesterol transport to and into the mitochondria, are of particular importance in age-related reductions in TS production. Although the mechanisms involved in these defects are far from certain, increasing oxidative stress appears to play a particularly important role. Interestingly, increased oxidative stress also appears to be involved in the suppressive effects of endocrine disruptors on Leydig cell TS production.

Steroidogenesis in Leydig cells: effects of aging and environmental factors.

Perfluorooctane sulfonate (PFOS) possibly delays male sexual development. However, its effects on pubertal Leydig cell development are unclear. The objective of the present study was to investigate the effects of in vivo PFOS exposure on rat Leydig cell development during puberty. Immature male Sprague Dawley rats were gavaged 5 or 10 mg/kg PFOS on postnatal day 35 for 21 days. Compared to the control (0 mg/kg), PFOS lowered serum testosterone levels without altering luteinizing hormone and follicle-stimulating hormone levels on postnatal day 56. PFOS in vivo downregulated mRNA or protein levels of Leydig cells (Lhcgr, Cyp11a1, and Cyp17a1). PFOS in vitro inhibited androgen secretion in immature Leydig cells at ≥ 50 nM, most possibly via downregulating Hsd17b3 mRNA level. At ≥ 500 nM, PFOS downregulated Lhcgr, inhibited BCL-2 and increased BAX levels to cause Leydig cell apoptosis. In conclusion, PFOS at a lower dose directly inhibited pubertal development of Leydig cells.

Perfluorooctane sulfonate impairs rat Leydig cell development during puberty.

The inability of cultured primary Leydig cells to maintain luteinizing hormone (LH)-responsive testosterone formation in vitro for more than 3-5 days has presented a major challenge in testing trophic effects of regulatory factors or environmental toxicants. Our primary objective was to establish culture conditions sufficient to maintain LH-responsive testosterone formation by Leydig cells for at least a month. When isolated rat adult Leydig cells were cultured in DMEM/F12 and M199 culture medium containing insulin (10μg/ml), PDGFAA (10 ng/ml), lipoprotein (0.25 mg/ml), horse serum (1%) and a submaximal concentration of LH (0.2 ng/ml), the cells retained the ability to produce testosterone in vitro for at least 4 weeks. By using the longer-term culture conditions of this system, we were able to detect suppressive effects on testosterone production by low levels of the toxicant MEHP (mono-(2-ethylhexyl) phthalate), an active metabolite of the plasticizer DEHP, that were not detected by short-term culture.

Long-term maintenance of luteinizing hormone-responsive testosterone formation by primary rat Leydig cells in vitro.

We reported that FGIN-1-27 (N,N-dihexyl-2-(4-fluorophenyl)indole-3-acetamide, FGIN), a synthetic ligand for translocator protein (TSPO, 18 kDa), increased serum testosterone levels in young and aged Brown Norway rats after its administration daily for 10 days. It is not known, however, how soon after treatment with FGIN serum testosterone rises, how long levels remain elevated after cessation of treatment, or whether the drug acts solely through TSPO. Adult Sprague-Dawley male rats received a single ip dose of FGIN (1 mg/kg BW). Serial blood samples were collected, and serum testosterone and luteinizing hormone (LH) were assessed hourly throughout 24 h. Testosterone concentration was maximal by 3 h, remained significantly higher than the controls at 10 h, and returned to the control level by 24 h. Consistent with the in vivo study, culturing isolated Leydig cells with either FGIN (40 μM) or LH (0.1 ng/ml) resulted in significantly increased testosterone production by 30 min, and the stimulatory effects persisted through 48 h. At a very early (15 min) treatment time, however, FGIN significantly increased testosterone production but LH had not yet done so. Surprisingly, in vivo treatment with FGIN not only increased serum testosterone but also serum LH concentration, raising the possibility that FGIN may increase serum testosterone concentration by dual mechanisms.

Acute effects of the translocator protein drug ligand FGIN-1-27 on serum testosterone and luteinizing hormone levels in male Sprague-Dawley rats†.

We reported previously that stem Leydig cells (SLC) on the surfaces of rat testicular seminiferous tubules are able to differentiate into Leydig cells. The proliferation and differentiation of SLCs seem likely to be regulated by niche cells, including nearby germ and Sertoli cells. Due to the cyclical nature of spermatogenesis, we hypothesized that the changes in the germ cell composition of the seminiferous tubules as spermatogenesis proceeds may affect tubule-associated SLC functions. To test this hypothesis, we compared the ability of SLCs associated with tubules at different stages of the cycle to differentiate into Leydig cells in vitro. SLCs associated with stages IX-XI were more active in proliferation and differentiation than SLCs associated with stages VII-VIII. However, when the SLCs were isolated from each of the two groups of tubules and cultured in vitro, no differences were seen in their ability to proliferate or differentiate. These results suggested that the stage-dependent local factors, not the SLCs themselves, explain the stage-dependent differences in SLC function. TGFB, produced in stage-specific fashion by Sertoli cells, is among the factors shown in previous studies to affect SLC function in vitro. When TGFB inhibitors were included in the cultures of stages IX-XI and VII-VIII tubules, stage-dependent differences in SLC development were reduced, suggesting that TGFB may be among the paracrine factors involved in the stage-dependent differences in SLC function. Taken together, the findings suggest that there is dynamic interaction between SLCs and germ/Sertoli cells within the seminiferous tubules that may affect SLC proliferation and differentiation.

Effects of spermatogenic cycle on Stem Leydig cell proliferation and differentiation.

It was reported previously that adult mouse stem Leydig cells (SLCs) express CD51 (integrin α-chain V). However, it is still unclear whether all CD51 cells are SLCs. In the present study, we found that CD51 cells can be classified into two sub-groups, a weakly-staining group (CD51) and a strongly-staining group (CD51). The CD51 cells expressed common SLC marker genes, including Nestin, Pdgfra and Coup-tf2, while CD51 cells did not express these genes. Instead, they expressed macrophage markers, such as F4/80, Cd115 and Tnfa. When these cells were induced to differentiate in vitro, the CD51 cells, but not CD51 cells, formed Leydig cells. Overall, our results showed that although SLCs expressed CD51, not all CD51-expressing cells are SLCs. The cells that expressed high levels of CD51 are actually macrophages.

Characterization and differentiation of CD51 Stem Leydig cells in adult mouse testes.

Adult testicular Leydig cells arise from stem cells in the neonatal and adult testis. The nature of these stem Leydig cells (SLCs) have not been well characterized. We have found previously that a group cells expressing CD90, a cell surface glycoprotein that may play roles in cell-cell and cell-matrix interactions and associated with the seminiferous tubule surface, have the ability to form Leydig cells. As yet, the relationship between this CD90+ cell population and SLCs reported previously by other groups is still unknown. In the present study, we systematically characterized these CD90+ cells by their ability to express multiple potential SLC markers and to proliferate and differentiate into Leydig cells in vitro. First, we have found by qPCR and immunohistochemical staining that the CD90+ cells do not express any of the markers of the common seminiferous tubular cells, including myoid, Sertoli, germ and Leydig cells, as well as macrophages. Moreover, when the CD90+ cells were isolated by fluorescent-sorting, the cells expressed high levels of all the potential SLC marker genes, including Nestin, Cd51, Coup-tf2, Arx, Pdgfra and Tcf21. Also, CD90-positive, but not -negative, cells were able to form Leydig cells in vitro with the proper inducing medium. Overall, the results indicated that the tubule-associated CD90+ cells represent a population of SLC in adult testis.

Characterization of stem cells associated with seminiferous tubule of adult rat testis for their potential to form Leydig cells.

Studies have shown that phthalates are capable of affecting the development and functions of male reproductive system. The effect of phthalates on Leydig cell functions is well documented. However, little is known about their potential effects on the functions of stem Leydig cells (SLC). In the present study, we have examined the effects of mono-(2-ethylhexyl) phthalate (MEHP) on SLC functions in vitro by culturing seminiferous tubules and isolated SLCs. The results indicate that MEHP can significantly inhibit the proliferation and differentiation of SLCs in both the organ and cell culture systems. Interestingly, the minimal effective concentration that is able to affect SLC function was lower in the tubule culture system (1 μM) than in the isolated cells (10 μM), suggesting a possible involvement of the niche cells. Also, MEHP appeared to affect both the efficiency of SLCs to form Leydig cells and a selected group of Leydig cell-specific genes, including Lhcgr, Scarb1, Hsd3b1, Cyp17a1, Star, Srd5a1, Akr1c14, Insl3, Hao2 and Pah. Since SLCs are multipotent, we also tested the effect of MEHP on the differentiation of SLCs to adipocytes. Though MEHP by itself can not specify SLCs into adipocyte lineage, it indeed significantly increased the adipogenic activity of SLCs if used with an adipocyte inducing medium by up-regulation of multiple adipogenic-related genes, including Pparg and Cebpa. Overall, the results indicate that MEHP inhibits SLCs differentiating into Leydig lineage while stimulates the differentiating potential of SLCs to adipocytes.

Phthalate inhibits Leydig cell differentiation and promotes adipocyte differentiation.

Peritubular stem Leydig cells (SLCs) have been identified from rat testicular seminiferous tubules. However, no stem cells for peritubular myoid cells have been reported in the adult testis so far. In the present study, we tested the hypothesis that the peritubular SLCs are multipotent and able to form either Leydig or myoid cells. Using cultured tubules, we show that in the presence of PDGFAA and luteinizing hormone, SLCs became testosterone-producing Leydig cells, while in the presence of PDGFBB and TGFB, the cells formed α-smooth muscle actin-expressing myoid cells. This multipotency was also confirmed by culture of isolated CD90 SLCs. These results suggest that these stem cells outside the myoid layer are multipotent and give rise to either Leydig or myoid cells, depending on the inducing factors. These cells may serve as a common precursor population for maintaining homeostasis of both Leydig and myoid cell populations in the adult testis.

Differentiation of seminiferous tubule-associated stem cells into leydig cell and myoid cell lineages.

Stem Leydig cells (SLCs) play a critical role in the development and maintenance of the adult Leydig cell (ALC) population. SLCs also are present in the adult testis. Their identification, characteristics, and regulation in the adult testis remain uncertain. Using single-cell RNA-seq, we found that the mesenchymal stromal population may be involved in ALC regeneration. Upon ALC elimination, a fraction of stromal cells begins to proliferate while a different fraction begins to differentiate to ALCs. Transcriptomic analysis identified five stromal clusters that can be classified into two major groups representing proliferation and differentiation populations. The proliferating group represents stem cells expressing high levels of CD90, Nes, Lum, Fn and Gap43. The differentiating group represents a progenitor stage that is ready to form ALCs, and specifically expresses Vtn, Rasl11a, Id1 and Egr2. The observation that the actively dividing cells after ALC loss were not those that formed ALCs suggests that stem cell proliferation and differentiation are regulated separately, and that the maintenance of the stromal stem cell pool occurs at the population level. The study also identified specific markers for the major interstitial cell groups and potential paracrine factors involved in the regulation of SLCs. Our data suggest a new theory about SLC identity, proliferation, differentiation, and regulation.

Identification of Rat Testicular Leydig Precursor Cells by Single-Cell-RNA-Sequence Analysis.

: To examine the associations of dietary patterns with frailty and whether metabolic signatures (MSs) mediate these associations. : We used UK Biobank data to examine (1) the associations of four dietary patterns (, alternate Mediterranean diet [aMED], Recommended Food Score [RFS], Dietary Approaches to Stop Hypertension [DASH] and Mediterranean-DASH Intervention for Neurodegenerative Delay [MIND] diet) with frailty (measured by the frailty phenotype and the frailty index) using multivariable logistic regression (analytic sample 1:  = 124 261; mean age = 57.7 years), and (2) the mediating role of MSs (weighted sums of the metabolites selected from 168 plasma metabolites using the LASSO algorithm) in the above associations  mediation analysis (analytic sample 2:  = 26 270; mean age = 57.7 years). : Four dietary patterns were independently associated with frailty (all  < 0.001). For instance, compared to participants in the lowest tertile for RFS, those in the intermediate (odds ratio [OR]: 0.81; 95% confidence interval [CI]: 0.74, 0.89) and highest (OR: 0.62; 95% CI: 0.56, 0.68) tertiles had a lower risk of frailty. We found that 98, 68, 123 and 75 metabolites were associated with aMED, RFS, DASH and MIND, respectively, including 16 common metabolites (, fatty acids, lipoproteins, acetate and glycoprotein acetyls). The MSs based on these metabolites partially mediated the association of the four dietary patterns with frailty, with the mediation proportion ranging from 26.52% to 45.83%. The results were robust when using another frailty measure, the frailty index. : The four dietary patterns were associated with frailty, and these associations were partially mediated by MSs. Adherence to healthy dietary patterns may potentially reduce frailty development by modulating metabolites.

Dietary patterns, metabolomics and frailty in a large cohort of 120 000 participants.

To investigate the associations between dynapenic obesity and the risk of dementia, and the modifying effects of age, sex, and the APOE gene, using a large population-based cohort.

ArticleTotal : 2	Year
Publication title	2023
Publication title	2024

Article	Year
Steroidogenesis in Leydig cells: effects of aging and environmental factors. Reproduction (Cambridge, England)\| PubMed ID: 28747539	2017
Perfluorooctane sulfonate impairs rat Leydig cell development during puberty. Chemosphere\| PubMed ID: 28985536	2018
Long-term maintenance of luteinizing hormone-responsive testosterone formation by primary rat Leydig cells in vitro. Molecular and cellular endocrinology\| PubMed ID: 29702242	2018
Acute effects of the translocator protein drug ligand FGIN-1-27 on serum testosterone and luteinizing hormone levels in male Sprague-Dawley rats†. Biology of reproduction\| PubMed ID: 30299464	2019
Effects of spermatogenic cycle on Stem Leydig cell proliferation and differentiation. Molecular and cellular endocrinology\| PubMed ID: 30476560	2019
Characterization and differentiation of CD51 Stem Leydig cells in adult mouse testes. Molecular and cellular endocrinology\| PubMed ID: 31102608	2019
Characterization of stem cells associated with seminiferous tubule of adult rat testis for their potential to form Leydig cells. Stem cell research\| PubMed ID: 31704538	2019
Phthalate inhibits Leydig cell differentiation and promotes adipocyte differentiation. Chemosphere\| PubMed ID: 32799149	2021
Differentiation of seminiferous tubule-associated stem cells into leydig cell and myoid cell lineages. Molecular and cellular endocrinology\| PubMed ID: 33515640	2021
Identification of Rat Testicular Leydig Precursor Cells by Single-Cell-RNA-Sequence Analysis. Frontiers in cell and developmental biology\| PubMed ID: 35242757	2022
Dietary patterns, metabolomics and frailty in a large cohort of 120 000 participants. Food & function\| PubMed ID: 38441259	2024
Age, sex, and APOE gene-specific associations between dynapenic obesity and dementia in a large cohort. The journal of nutrition, health & aging\| PubMed ID: 38986174	2024

Fenfen Chen

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