Search tips
Search criteria

Results 1-8 (8)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Intravenous Multipotent Adult Progenitor Cell Therapy Attenuates Activated Microglial/Macrophage Response and Improves Spatial Learning After Traumatic Brain Injury 
Stem Cells Translational Medicine  2013;2(12):953-960.
It was hypothesized that the intravenous injection of multipotent adult progenitor cells (MAPCs) after traumatic brain injury (TBI) attenuates the inflammatory response and improves performance at motor tasks and spatial learning. MAPCs were administered intravenously to rodents 2 and 24 hours after a cortical contusion injury. It was found that intravenous MAPC treatment offers long-term improvements in cognitive behavior after TBI.
We previously demonstrated that the intravenous delivery of multipotent adult progenitor cells (MAPCs) after traumatic brain injury (TBI) in rodents provides neuroprotection by preserving the blood-brain barrier and systemically attenuating inflammation in the acute time frame following cell treatment; however, the long-term behavioral and anti-inflammatory effects of MAPC administration after TBI have yet to be explored. We hypothesized that the intravenous injection of MAPCs after TBI attenuates the inflammatory response (as measured by microglial morphology) and improves performance at motor tasks and spatial learning (Morris water maze [MWM]). MAPCs were administered intravenously 2 and 24 hours after a cortical contusion injury (CCI). We tested four groups at 120 days after TBI: sham (uninjured), injured but not treated (CCI), and injured and treated with one of two concentrations of MAPCs, either 2 million cells per kilogram (CCI-2) or 10 million cells per kilogram (CCI-10). CCI-10 rats showed significant improvement in left hind limb deficit on the balance beam. On the fifth day of MWM trials, CCI-10 animals showed a significant decrease in both latency to platform and distance traveled compared with CCI. Probe trials revealed a significant decrease in proximity measure in CCI-10 compared with CCI, suggesting improved memory retrieval. Neuroinflammation was quantified by enumerating activated microglia in the ipsilateral hippocampus. We observed a significant decrease in the number of activated microglia in the dentate gyrus in CCI-10 compared with CCI. Our results demonstrate that intravenous MAPC treatment after TBI in a rodent model offers long-term improvements in spatial learning as well as attenuation of neuroinflammation.
PMCID: PMC3841090  PMID: 24191266
Adult stem cells; Neuroimmune; Rat model; Stem/progenitor cell
2.  Intravenous multipotent adult progenitor cell therapy for traumatic brain injury: Preserving the blood brain barrier via an interaction with splenocytes 
Experimental neurology  2010;225(2):341-352.
Recent investigation has shown an interaction between transplanted progenitor cells and resident splenocytes leading to modulation of the immunologic response in neurological injury. We hypothesize that the intravenous injection of multipotent adult progenitor cells (MAPC) confers neurovascular protection after traumatic brain injury through an interaction with resident splenocytes, subsequently leading to preservation of the blood brain barrier.
Four groups of rats underwent controlled cortical impact injury (3 groups) or sham injury (1 group). MAPC were injected via the tail vein at two doses (2*106 MAPC/kg or 10*106 MAPC/kg) 2 and 24 hours after injury. Blood brain barrier permeability was assessed by measuring Evans blue dye extravasation (n=6/group). Additionally, splenic mass was measured (n=12/group) followed by splenocyte characterization (n=9/group) including: cell cycle analysis (n=6/group), apoptosis index (n=6/group), cell proliferation (n=6/group), and inflammatory cytokine measurements (n=6/group). Vascular architecture was determined by immunohistochemistry (n=3/group).
Traumatic brain injury results in a decrease in splenic mass and increased blood brain barrier permeability. Intravenous infusion of MAPC preserved splenic mass and returned blood brain barrier permeability towards control sham injured levels. Splenocyte characterization indicated an increase in the number and proliferative rate of CD4+ T cells as well as an increase in IL-4 and IL-10 production in stimulated splenocytes isolated from the MAPC treatment groups. Immunohistochemistry demonstrated stabilization of the vascular architecture in the peri-lesion area
Traumatic brain injury causes a reduction in splenic mass that correlates with an increase in circulating immune cells leading to increased blood brain barrier permeability. The intravenous injection of MAPC preserves splenic mass and the integrity of the blood brain barrier. Furthermore, the co-localization of transplanted MAPC and resident CD4+ splenocytes is associated with a global increase in IL-4 and IL-10 production and stabilization of the cerebral microvasculature tight junction proteins.
PMCID: PMC3774549  PMID: 20637752
Multipotent adult progenitor cells; traumatic brain injury; stem cells; splenocytes; blood brain barrier
3.  Multipotent Adult Progenitor Cells Prevent Macrophage-Mediated Axonal Dieback and Promote Regrowth after Spinal Cord Injury 
Macrophage-mediated axonal dieback presents an additional challenge to regenerating axons after spinal cord injury. Adult adherent stem cells are known to have immunomodulatory capabilities, but their potential to ameliorate this detrimental inflammation-related process has not been investigated. Using an in vitro model of axonal dieback as well as an adult rat dorsal column crush model of spinal cord injury, we found that multipotent adult progenitor cells (MAPCs) can affect both macrophages and dystrophic neurons simultaneously. MAPCs significantly decrease MMP-9 (matrix metalloproteinase-9) release from macrophages, effectively preventing induction of axonal dieback. MAPCs also induce a shift in macrophages from an M1, or “classically activated” proinflammatory state, to an M2, or “alternatively activated” antiinflammatory state. In addition to these effects on macrophages, MAPCs promote sensory neurite outgrowth, induce sprouting, and further enable axons to overcome the negative effects of macrophages as well as inhibitory proteoglycans in their environment by increasing their intrinsic growth capacity. Our results demonstrate that MAPCs have therapeutic benefits after spinal cord injury and provide specific evidence that adult stem cells exert positive immunomodulatory and neurotrophic influences.
PMCID: PMC3560969  PMID: 21248119
4.  Intravenous multipotent adult progenitor cell therapy after traumatic brain injury: modulation of the resident microglia population 
We have demonstrated previously that the intravenous delivery of multipotent adult progenitor cells (MAPC) after traumatic brain injury affords neuroprotection via interaction with splenocytes, leading to an increase in systemic anti-inflammatory cytokines. We hypothesize that the observed modulation of the systemic inflammatory milieu is related to T regulatory cells and a subsequent increase in the locoregional neuroprotective M2 macrophage population.
C57B6 mice were injected with intravenous MAPC 2 and 24 hours after controlled cortical impact injury. Animals were euthanized 24, 48, 72, and 120 hours after injury. In vivo, the proportion of CD4+/CD25+/FOXP3+ T-regulatory cells were measured in the splenocyte population and plasma. In addition, the brain CD86+ M1 and CD206+ M2 macrophage populations were quantified. A series of in vitro co-cultures were completed to investigate the need for direct MAPC:splenocyte contact as well as the effect of MAPC therapy on M1 and M2 macrophage subtype apoptosis and proliferation.
Significant increases in the splenocyte and plasma T regulatory cell populations were observed with MAPC therapy at 24 and 48 hours, respectively. In addition, MAPC therapy was associated with an increase in the brain M2/M1 macrophage ratio at 24, 48 and 120 hours after cortical injury. In vitro cultures of activated microglia with supernatant derived from MAPC:splenocyte co-cultures also demonstrated an increase in the M2/M1 ratio. The observed changes were secondary to an increase in M1 macrophage apoptosis.
The data show that the intravenous delivery of MAPC after cortical injury results in increases in T regulatory cells in splenocytes and plasma with a concordant increase in the locoregional M2/M1 macrophage ratio. Direct contact between the MAPC and splenocytes is required to modulate activated microglia, adding further evidence to the central role of the spleen in MAPC-mediated neuroprotection.
PMCID: PMC3546881  PMID: 23020860
Multipotent adult progenitor cells; Traumatic brain injury; Stem cells; Splenocytes; Blood brain barrier; Microglia
5.  Update On Stem Cell Therapy For Cerebral Palsy 
Due to the publicity about stem cell transplantation for the treatment of cerebral palsy, many families seek information on treatment, and many travel overseas for cell transplantation. Even so, there is little scientific confirmation of benefit, and therefore existing knowledge in the field must be summarized.
Areas covered
This paper addresses the clinical protocols examining the problem, types of stem cells available for transplant, experimental models used to test the benefit of the cells, possible mechanisms of action, potential complications of cell treatment, and what is needed in the field to help accelerate cell-based therapies.
Expert Opinion
While stem cells may be beneficial in acute injuries of the central nervous system, the biology of stem cells is not well enough understood in chronic injuries or disorders such as cerebral palsy. More work is required at the basic level of stem cell biology, in the development of animal models, and finally in well-conceived clinical trials.
PMCID: PMC3057381  PMID: 21299445
Animal models; cerebral palsy; embryonic stem cells; induced pluripotent stem cells; mesenchymal cells; multipotent adult progenitor cells; stem cells; transplantation
6.  Intravenous grafts recapitulate the neurorestoration afforded by intracerebrally delivered multipotent adult progenitor cells in neonatal hypoxic–ischemic rats 
Once hypoxic–ischemic (HI) injury ensues in the human neonate at birth, the resulting brain damage lasts throughout the individual’s lifetime, as no ameliorative treatments are currently available. We have recently shown that intracerebral transplantation of multipotent adult progenitor cells (MAPCs) results in behavioral improvement and reduction in ischemic cell loss in neonatal rat HI-injury model. In an attempt to advance this cellular therapy to the clinic, we explored the more practical and less invasive intravenous administration of MAPCs. Seven-day-old Sprague–Dawley rats were initially subjected to unilateral HI injury, then 7 days later received intracerebral or intravenous injections of allogeneic rat MAPCs. On post-transplantation days 7 and 14, the animals that received MAPCs via the intracerebral or intravenous route exhibited improved motor and neurologic scores compared with those that received vehicle infusion alone. Immunohistochemical evaluations at day 14 after transplantation revealed that both intracerebrally and intravenously transplanted MAPCs were detected in the ischemic hippocampal area. The degree of hippocampal cell preservation was almost the same in the two treatment groups and greater than that in the vehicle group. These results show that intravenous delivery of MAPCs is a feasible and efficacious cell therapy with potential for clinical use.
PMCID: PMC2587070  PMID: 18594556
transplantation; stem cells; neural progenitors; cell migration; animal behavior
7.  Identification of a Novel Extracellular Cation-sensing G-protein-coupled Receptor* 
The Journal of biological chemistry  2005;280(48):40201-40209.
The C family G-protein-coupled receptors contain members that sense amino acid and extracellular cations, of which calcium-sensing receptor (CASR) is the prototypic extracellular calcium-sensing receptor. Some cells, such as osteoblasts in bone, retain responsiveness to extracellular calcium in CASR-deficient mice, consistent with the existence of another calcium-sensing receptor. We examined the calcium-sensing properties of GPRC6A, a newly identified member of this family. Alignment of GPRC6A with CASR revealed conservation of both calcium and calcimimetic binding sites. In addition, calcium, magnesium, strontium, aluminum, gadolinium, and the calcimimetic NPS 568 resulted in a dose-dependent stimulation of GPRC6A overexpressed in human embryonic kidney cells 293 cells. Also, osteocalcin, a calcium-binding protein highly expressed in bone, dose-dependently stimulated GPRC6A activity in the presence of calcium but inhibited the calcium-dependent activation of CASR. Coexpression of β-arrestins 1 and 2, regulators of G-protein signaling RGS2 or RGS4, the RhoA inhibitor C3 toxin, the dominant negative Gαq-(305–359) minigene, and pretreatment with pertussis toxin inhibited activation of GPRC6A by extracellular cations. Reverse transcription-PCR analyses showed that mouse GPRC6A is widely expressed in mouse tissues, including bone, calvaria, and the osteoblastic cell line MC3T3-E1. These data suggest that in addition to sensing amino acids, GPRC6A is a cation-, calcimimetic-, and osteocalcin-sensing receptor and a candidate for mediating extracellular calcium-sensing responses in osteoblasts and possibly other tissues.
PMCID: PMC1435382  PMID: 16199532
8.  Human Artificial Chromosomes with Alpha Satellite-Based De Novo Centromeres Show Increased Frequency of Nondisjunction and Anaphase Lag 
Molecular and Cellular Biology  2003;23(21):7689-7697.
Human artificial chromosomes have been used to model requirements for human chromosome segregation and to explore the nature of sequences competent for centromere function. Normal human centromeres require specialized chromatin that consists of alpha satellite DNA complexed with epigenetically modified histones and centromere-specific proteins. While several types of alpha satellite DNA have been used to assemble de novo centromeres in artificial chromosome assays, the extent to which they fully recapitulate normal centromere function has not been explored. Here, we have used two kinds of alpha satellite DNA, DXZ1 (from the X chromosome) and D17Z1 (from chromosome 17), to generate human artificial chromosomes. Although artificial chromosomes are mitotically stable over many months in culture, when we examined their segregation in individual cell divisions using an anaphase assay, artificial chromosomes exhibited more segregation errors than natural human chromosomes (P < 0.001). Naturally occurring, but abnormal small ring chromosomes derived from chromosome 17 and the X chromosome also missegregate more than normal chromosomes, implicating overall chromosome size and/or structure in the fidelity of chromosome segregation. As different artificial chromosomes missegregate over a fivefold range, the data suggest that variable centromeric DNA content and/or epigenetic assembly can influence the mitotic behavior of artificial chromosomes.
PMCID: PMC207596  PMID: 14560014

Results 1-8 (8)