Preconditioning of Hypoxic Culture Increases The Therapeutic Potential of Adipose Derived Mesenchymal Stem Cells

Various in vitro preconditioning strategies have been implemented to increase the regenerative capacity of MSCs. Among them are modulation of culture atmosphere (hypoxia or anoxia), three-dimensional culture (3D), addition of trophic factors (in the form of growth factors, cytokines or hormones), lipopolysaccharides, and pharmacological agents. Preconditioning mesenchymal stem cells by culturing them in a hypoxic environment, which resembles the natural oxygen environment of the tissues (1% –7%) and not with standard culture conditions (21%), increases the survival of these cells via Hypoxia Inducible Factor-1α (HIF-1a) and via Akt-dependent mechanisms. In addition, the hypoxic precondition stimulates the secretion of pro-angiogenic growth factors, increases the expression of chemokines SDF-1 (stromal cell-derived factor-1) and its receptor CXCR4 (chemokine receptor type 4) - CXCR7 (chemokine receptor type 7) and increases engraftment of stem cell. This review aims to provide an overview of the preconditioned hypoxic treatment to increase the therapeutic potential of adipose-derived mesenchymal stem cells.

Enhancement of Chondrogenesis in Hypoxic Precondition Culture: A Systematic Review

BACKGROUND: Cartilage tear has begun to be treated with stem cells. However, stem cell oxygen level culture has not been evaluated for the best environment to enhance chondrogenesis. AIM: The purpose of this review is to focus on the hypoxic oxygen level of stem cells culture as a treatment for cartilage tear. METHODS: A literature search was systemically conducted on PubMed (MEDLINE), OVID, EMBASE, the Cochrane Library, Scopus, Web of Science, Science Direct, Wiley Online Library, Google Scholar, and bibliography of selected articles with the terms (“culture”) AND (“stem cell” OR “mesenchymal stem cell” OR “MSC”) AND (“hypoxic” OR “hypoxia”) AND (“cartilage” OR “chondro*”) as the main keywords. A total of 438 articles were reviewed. Thirty-six articles were considered relevant for this systematic review. RESULTS: The result of this review supports stimulation effects of hypoxic oxygen level stem cell culture in chondrogenesis process. Most studies used 5% oxygen concentration for culture, both of in vivo and in vitro studies. Due to the heterogeneity nature of the included studies, meta-analysis was unable to be conducted. CONCLUSION: Hypoxia state seems to play an important role in chondrocytes proliferation, differentiation, and matrix production.

Topical application of adipose tissue-derived mesenchymal stem cells (ADMSCs) reduced cerebral edema in experimental traumatic brain injury (TBI)—a preliminary study

Background Our previous studies showed that topical application of mesenchymal stem cells (MSCs) improved functional recovery in rat traumatic brain injury (TBI) model, and hypoxic precondition further enhanced the therapeutic effects of MSCs. There was no previous study on the attenuation of cerebral edema by MSCs. We investigated whether topical application of normoxic and hypoxic MSCs could reduce cerebral edema in an experimental TBI model. Methods Two million normoxic (N = 24) and hypoxic (N = 24) MSCs were applied topically to exposed the cerebral cortex in a controlled cortical impact (CCI) model. The MSCs were fixed in position with fibrin glue. No treatment was given to control animals (TBI only: n = 24). After surgery, four animals in each group were sacrificed daily (day 1 to day 6) for edema evaluation. Normal animals without TBI were used as reference (n = 4). The expressions of GFAP, AQP4, and MMP9 were also investigated by immunofluorescence staining and RT-PCR at day 3. Results The edema peaked within 3 days after TBI. Compared with the control, hypoxic MSCs reduced brain water content significantly (p < 0.05). Both hypoxic and normoxic MSCs downregulated the expression of MMP9 and normalized AQP4 distribution to astrocyte end feet. Conclusion Our preliminary study showed that topical application of hypoxic MSCs suppressed both vasogenic and cytotoxic edema formation.

Topical application of adipose tissue derived mesenchymal stem cells (ADMSCs) reduced cerebral edema in experimental traumatic brain injury (TBI)- a preliminary study

Background:Our previous studies showed that topical application of mesenchymal stem cells (MSCs) improved functional recovery in rat traumatic brain injury (TBI) model, and hypoxic precondition further enhanced the therapeutic effects of MSCs. There was no previous study on the attenuation of cerebral edema by MSCs.Objective:We investigated whether topical application of normoxic and hypoxic MSCs could reduce cerebral edema in an experimental TBI model.Methods:2 million normoxic (N=24) and hypoxic (N=24) MSCs were applied topically to exposed cerebral cortex in a controlled cortical impact (CCI) model. The MSCs were fixed in position with fibrin glue. No treatment was given to control animals (TBI only: n=24). After surgery, four animals in each group were sacrificed daily (day 1 to day 6) for edema evaluation. Normal animals without TBI were used as reference (n=4). The expressions of GFAP, AQP4 and MMP9 were also investigated by immunofluorescence staining and RT-PCR at day 3. Results:The edema peaked within 3 days after TBI. Compared with the control, hypoxic MSCs reduced brain water content significantly (p<0.05). Both hypoxic and normoxic MSCs downregulated the expression of MMP9 and normalized AQP4 distribution to astrocytes end feet.Conclusion:Our preliminary study showed that topical application of hypoxic MSCs suppressed both vasogenic and cytotoxic edema formation.

Topical application of adipose tissue derived mesenchymal stem cells (ADMSCs) reduced cerebral edema in experimental traumatic brain injury (TBI)- a preliminary study

Background: Our previous studies showed that topical application of mesenchymal stem cells (MSCs) improved functional recovery in rat traumatic brain injury (TBI) model, and hypoxic precondition further enhanced the therapeutic effects of MSCs. There was no previous study on the attenuation of cerebral edema by MSCs. Objective: We investigated whether topical application of normoxic and hypoxic MSCs could reduce cerebral edema in an experimental TBI model. Methods: 2 million normoxic (N=24) and hypoxic (N=24) MSCs were applied topically to exposed cerebral cortex in a controlled cortical impact (CCI) model. The MSCs were fixed in position with fibrin glue. No treatment was given to control animals (TBI only: n=24). After surgery, four animals in each group were sacrificed daily (day 1 to day 6) for edema evaluation. Normal animals without TBI were used as reference (n=4). The expressions of GFAP, AQP4 and MMP9 were also investigated by immunofluorescence staining and RT-PCR at day 3. Results: The edema peaked within 3 days after TBI. Compared with the control, hypoxic MSCs reduced brain water content significantly (p<0.05). Both hypoxic and normoxic MSCs downregulated the expression of MMP9 and normalized AQP4 distribution to astrocytes end feet. Conclusion: Our preliminary study showed that topical application of hypoxic MSCs suppressed both vasogenic and cytotoxic edema formation.

Topical application of adipose tissue derived mesenchymal stem cells (ADMSCs) reduced cerebral edema in experimental traumatic brain injury (TBI)- a preliminary study

Background: Our previous studies showed that topical application of mesenchymal stem cells (MSCs) improved functional recovery in rat traumatic brain injury (TBI) model, and hypoxic precondition further enhanced the therapeutic effects of MSCs. There was no previous study on the attenuation of cerebral edema by MSCs. Objective: We investigated whether topical application of normoxic and hypoxic MSCs could reduce cerebral edema in an experimental TBI model. Methods: 2 million normoxic (N=24) and hypoxic (N=24) MSCs were applied topically to exposed cerebral cortex in a controlled cortical impact (CCI) model. The MSCs were fixed in position with fibrin glue. No treatment was given to control animals (TBI only: n=24). After surgery, four animals in each group were sacrificed daily (day 1 to day 6) for edema evaluation. Normal animals without TBI were used as reference (n=4). The expressions of GFAP, AQP4 and MMP9 were also investigated by immunofluorescence staining and RT-PCR at day 3. Results: The edema peaked within 3 days after TBI. Compared with the control, hypoxic MSCs reduced brain water content significantly (p<0.05). Both hypoxic and normoxic MSCs downregulated the expression of MMP9 and normalized AQP4 distribution to astrocytes end feet. Conclusion: Our preliminary study showed that topical application of hypoxic MSCs suppressed both vasogenic and cytotoxic edema formation. Keywords: topical, MSCs, cerebral edema, TBI

The Hypoxic Preconditioning Effect On Senescence Cell Process In Cultured Adipose-Derived Mesenchymal Stem Cells (AMSCs)

Introduction : Stem cell therapy for myocardial regeneration is expected to increase cardiomyocyte proliferation and trigger neovascularization to improve cardiomyocytes. Mesenchymal Stem Cells (MSCs) are ideal candidates for regenerative medicine and immunotherapy. But low viability of MSCs is a major challenge in this alternative therapy. Therefore, a cytoprotective strategy is needed, one of them is hypoxic preconditioning which can significantly increase survival stem cells after being transplanted. MSCs are known to have a limited life span, after experiencing several splits MSC will enter the senescence process. It is known that hypoxia can also increase cell proliferation and differentiation potential in vitro and in vivo through the role of Octamer-4 (Oct-4) as a regulator of the pluripotency gene. Methods : Experimental laboratory studies (in vitro studies) using human-AMSCs which were given hypoxic preconditioning, observed as a immunocytochemistry. Results : The results showed that hypoxic precondition (1% O2) inhibited the senescence process. It can be seen in the lower expression of senescence in hypoxic conditions at P6, P7, P8, P9, P10 compared to normoxic ((p=0,004, p=0,001, p=0,009, p=0,013, p=0,024. There is a significant difference in the senescence expression of each passage in hypoxic and normoxic conditions with the highest expression at P10. In addition, we also observed AMSCs differentiation through the Oct-4 expression. It is showed that Oct-4 expression were higher in hypoxia compared to normoxia on P7, P8, P9, P10 (p=0,009, p=0,009, p=0,030, p=0,0001). Conclusions : Hypoxic preconditioning have the effect of inhibiting the senescence process on Adipose-derived MSCs (AMSCs) or prolonging their life span. The longer life span of AMSCs is also seen by higher cell differentiation potential from increased expression of Oct-4. However, the mechanism of inhibiting the senescence process in hypoxia in stem cells is still remain unknown. Keywords: human-Adipose derived Mesenchymal Stem Cell Cultures (h-AMSCs), Hypoxic Preconditioning, Senescence cell, Oct-4.

Xerostomia Therapy Due to Ionized Radiation Using Preconditioned Bone Marrow-Derived Mesenchymal Stem Cells

Objectives The aim of this study was to describe the process of regeneration of damaged salivary glands due to ionizing radiations by bone marrow mesenchymal stem cells (BM-MSCs) transplantation that have been given hypoxic preconditioning with 1% O2 concentration. Materials and Methods Stem cell culture was performed under normoxic (O2: 21%) and hypoxic conditions by incubating the cells for 48 hours in a low oxygen tension chamber consisting of 95% N2, 5% CO2, and 1% O2. Thirty male Wistar rats were divided into four groups: two groups of control and two groups of treatment. A single dose of 15 Gy radiation was provided to the ventral region of the neck in all treatment groups, damaging the salivary glands. BM-MSCs transplantation was performed in the treatment groups for normoxia and hypoxia 24-hour postradiation. Statistical Analysis Statistical analysis was done using normality test, followed by MANOVA test (p < 0.05). Results There was a significant difference in the expression of binding SDF1-CXCR4, Bcl-2 (p < 0.05) and also the activity of the enzyme α-amylase in all groups of hypoxia. Conclusion BM-MSCs transplantation with hypoxic precondition increases the expression of binding SDF1-CXCR4, Bcl-2 that contributes to cell migration, cell survival, and cell differentiation.