Blood pressure lowering enhances cerebrospinal fluid efflux to the systemic circulation primarily via the lymphatic vasculature.

BACKGROUND: Inside the incompressible cranium, the volume of cerebrospinal fluid is directly linked to blood volume: a change in either will induce a compensatory change in the other. Vasodilatory lowering of blood pressure has been shown to result in an increase of intracranial pressure, which, in normal circumstances should return to equilibrium by increased fluid efflux. In this study, we investigated the effect of blood pressure lowering on fluorescent cerebrospinal fluid tracer absorption into the systemic blood circulation. METHODS: Blood pressure lowering was performed by an i.v. administration of nitric oxide donor (sodium nitroprusside, 5 µg kg-1 min-1) or the Ca2+-channel blocker (nicardipine hydrochloride, 0.5 µg kg-1 min-1) for 10, and 15 to 40 min, respectively. The effect of blood pressure lowering on cerebrospinal fluid clearance was investigated by measuring the efflux of fluorescent tracers (40 kDa FITC-dextran, 45 kDa Texas Red-conjugated ovalbumin) into blood and deep cervical lymph nodes. The effect of nicardipine on cerebral hemodynamics was investigated by near-infrared spectroscopy. The distribution of cerebrospinal fluid tracers (40 kDa horse radish peroxidase,160 kDa nanogold-conjugated IgG) in exit pathways was also analyzed at an ultrastructural level using electron microscopy. RESULTS: Nicardipine and sodium nitroprusside reduced blood pressure by 32.0 ± 19.6% and 24.0 ± 13.3%, while temporarily elevating intracranial pressure by 14.0 ± 7.0% and 18.2 ± 15.0%, respectively. Blood pressure lowering significantly increased tracer accumulation into dorsal dura, deep cervical lymph nodes and systemic circulation, but reduced perivascular inflow along penetrating arteries in the brain. The enhanced tracer efflux by blood pressure lowering into the systemic circulation was markedly reduced (- 66.7%) by ligation of lymphatic vessels draining into deep cervical lymph nodes. CONCLUSIONS: This is the first study showing that cerebrospinal fluid clearance can be improved with acute hypotensive treatment and that the effect of the treatment is reduced by ligation of a lymphatic drainage pathway. Enhanced cerebrospinal fluid clearance by blood pressure lowering may have therapeutic potential in diseases with dysregulated cerebrospinal fluid  flow.

Altered cerebrovascular-CSF coupling in Alzheimer's Disease measured by functional near-infrared spectroscopy.

In-vivo microscopical studies indicate that brain cerebrospinal fluid (CSF) transport driven by blood vessel pulsations is reduced in the early stages of Alzheimer's disease (AD). We hypothesized that the coupling pattern between cerebrovascular pulsations and CSF is altered in AD, and this can be measured using multi-wavelength functional near-infrared spectroscopy (fNIRS). To study this, we quantified simultaneously cerebral hemo- and CSF hydrodynamics in early AD patients and age-matched healthy controls. Physiological pulsations were analysed in the vasomotor very low frequency (VLF 0.008-0.1 Hz), respiratory (Resp. 0.1-0.6 Hz), and cardiac (Card. 0.6-5 Hz) bands. A sliding time window cross-correlation approach was used to estimate the temporal stability of the cerebrovascular-CSF coupling. We investigated how the lag time series variation of the coupling differs between AD patients and control. The couplings involving deoxyhemoglobin (HbR) and CSF water, along with their first derivative, in the cardiac band demonstrated significant difference between AD patients and controls. Furthermore, the lag time series variation of HbR-CSF in the cardiac band provided a significant relationship, p-value = 0.04 and r2 = 0.16, with the mini-mental state exam (MMSE) score. In conclusion, the coupling pattern between hemodynamics and CSF is reduced in AD and it correlates with MMSE score.

Biomimetic scaffold containing PVDF nanofibers with sustained TGF-ß release in combination with AT-MSCs for bladder tissue engineering.

Since the functional recovery of the reconstructed bladder is related to the bladder wall contraction and existing therapies do not respond to this, tissue engineering could be worth considered promising candidates for developing of conventional treatments in these kinds of ailments. Due to the low mechanical properties of natural scaffolds, biocompatible synthetic scaffolds can play a key role in the stem cells proliferation and differentiation and apply for many tissue-engineering applications. On the other hand, considering the low shelf life of TGFß, encapsulating this growth factor can help maintain its functionality throughout the study period. In this study, poly (vinylidene fluoride) (PVDF) nanofibrous scaffolds were fabricated through electrospinning method with or without chitosan nanoparticles loaded TGFß. All scaffolds characterized morphologically by using SEM, TGFß release profiling as well as biocompatibility by using SEM and MTT assays. Adipose tissue derived mesenchymal stem cells (AT-MSCs) was isolated and characterized immediately and the differentiation of SMC was investigated when cultured on the surface of the scaffolds and tissue culture polystyrene (TCPS) as a control of gene and protein expression levels. Fabricated scaffold possess smooth structure with nanoscale size and long time releasing of sustained profiles. MTT, qRT-PCR and immunocytochemistry results demonstrated that AT-MSCs proliferation rate and SMC differentiation potential were significantly increased when cultured on the PVDF-TGFß scaffold in comparison with PVDF and TCPS. According to the results, PVDF-TGFß as a bio-functional scaffold can provide greater treatment possibilities in bladder tissue engineering applications.

Bone tissue engineering: Adult stem cells in combination with electrospun nanofibrous scaffolds.

Since bone tissue lesions caused by several reasons and has global outbreak without any attentions to the modernity level of the countries. In the other hands treatment of patients with this problem faced to the several limitations, in this because the future of the bone lesions treatments is related to the future of the bone tissue engineering. This review tries to cover the most suitable stem cells and materials from either natural or synthetic sources for bone tissue engineering. These understanding points would help researchers to further uncover the application of different adult stem cell sources in electrospinning scaffolds, promotion of nanofibrous composite construct design and adult stem cell type selection to enhance cell function and bone tissue engineering, and link laboratory investigations to clinical applications.

Collagen-graft mixed cellulose esters membrane maintains undifferentiated morphology and markers of potential pluripotency in feeder-free culture of induced pluripotent stem cells.

Induced pluripotent stem cells (iPSCs) are unique and unlimited clinical sources of stem cell therapy for the regenerative medicine. Feeder layer preparation is an important step for iPSCs production, which is expensive, time-consuming and requires conversance. In the present study, we investigated the maintenance of pluripotency, and stemness of the iPSCs through feeder-free culture on a collagen-grafted Mixed Cellulose Esters membrane (MCE-COL) after three passages during twelve days. Results have demonstrated that the iPSCs cultured on MCE-COL membrane had a fine, typical undifferentiated morphology, increased proliferation rate and significant multi-lineage differentiation potential. Alkaline phosphatase (ALP) staining and pluripotency associated gene markers expression further confirmed that iPSCs cultured on the surface of MCE-COL had more ALP positive colonies and enhanced expression of Oct-4, Nanog, Sox-2 and ALP in comparison with MCE and control groups. Since MCE-COL membrane has three dimensional structure and bioactivity, it has the potential for usage in the feeder-free culture of iPSCs, and could be a suitable candidate to use as a feeder layer in stem cells preparation.

Role of Helicobacter pylori on cancer of human adipose-derived mesenchymal stem cells and metastasis of tumor cells-an in vitro study.

Recent studies have shown that Helicobacter pylori has a special role in tropism of mesenchymal stem cells (MSCs) towards gastric tissues. This study aimed to find the effects of H. pylori on human adipose-derived mesenchymal stem cells (hA-MSCs) transforming toward cancer cells and also metastasis of tumor cells by synergic effects of H. pylori and gastric epithelial cells (AGS) on MSCs. The expressions of p53, bcl-2, MMP-2, and MMP-9 were examined in hA-MSCs by qRT-PCR technique. Our results demonstrated that H. pylori tries to improve the hA-MSCs carcinogenic activities by overexpression of bcl2 gene as an anti-apoptosis agent against the p53 gene expression as main apoptosis agent. In addition, it showed that H. pylori effects in metastatic activities of hA-MSCs by upregulation of related genes in this process. Perhaps, when hA-MSCs are attracted toward H. pylori chronic or ulcer infected tissues for their tissue healing function, they will be trapped under special gastric microenvironment. We demonstrated the direct and synergic effects of H. pylori in hA-MSCs through alteration of related genes involved in carcinogenesis processes. Hence, understanding of H. pylori-induced molecular pathogenesis could be a powerful strategy not only in identifying the origin and initiation of gastric cancer but also in the treatment of related disease and modification of stem cell therapy methods in the future.

Immunomodulatory effects of adipose-derived mesenchymal stem cells on the gene expression of major transcription factors of T cell subsets.

It has been proposed that the immunomodulatory properties of mesenchymal stem cells (MSCs) play a crucial role in establishing and leading T lymphocytes, especially Th cell subsets, toward different functional subsets. To determine the effect of the immunomodulatory and regulatory functions of adipose-derived MSCs (AD-MSCs) on C57BL/6 spleen-isolated mononuclear cells (Spleen-MNCs), the gene expression of well-known effector and regulatory Th cell-related transcription factors, i.e., t-bet, GATA-3, Ror-γt and Foxp3, and their related cytokines, i.e., IFN-γ for Th1 cells, IL-4 for Th2 cells, IL-17 for Th17 cells and IL-10 and TGF-ß for regulatory T cells, was studied using a co-culture condition system. The proliferation index of Spleen-MNCs was analyzed using a cell proliferation assay kit that utilized the CFSE staining method. Our findings indicate that AD-MSCs greatly impact the up-regulation of immunomodulatory cytokines, such as TGF-ß (p<0.001), and the down-regulation of inflammatory cytokines, such as IFN-γ (p<0.005), and transcription factors, such as t-bet (p<0.001). Considering the immunomodulatory effects of MSCs in the differentiation of Th cell subsets, understanding and harnessing this property of MSCs could be a powerful strategy in the treatment of inflammatory autoimmune diseases such as multiple sclerosis.

Bioceramic-collagen scaffolds loaded with human adipose-tissue derived stem cells for bone tissue engineering.

The combination of bioceramics and stem cells has attracted the interest of research community for bone tissue engineering applications. In the present study, a combination of Bio-Oss(®) and type 1 collagen gel as scaffold were loaded with human adipose-tissue derived mesenchymal stem cells (AT-MSCs) after isolation and characterization, and the capacity of them for bone regeneration was investigated in rat critical size defects using digital mammography, multi-slice spiral computed tomography imaging and histological analysis. 8 weeks after implantation, no mortality or sign of inflammation was observed in the site of defect. According to the results of imaging analysis, a higher level of bone regeneration was observed in the rats receiving Bio-Oss(®)-Gel compared to untreated group. In addition, MSC-seeded Bio-Oss-Gel induced the highest bone reconstruction among all groups. Histological staining confirmed these findings and impressive osseointegration was observed in MSC-seeded Bio-Oss-Gel compared with Bio-Oss-Gel. On the whole, it was demonstrated that combination of AT-MSCs, Bio-Oss and Gel synergistically enhanced bone regeneration and reconstruction and also could serve as an appropriate structure to bone regenerative medicine and tissue engineering application.