Treatment of traumatic brain injury in adult rats with intravenous administration of human bone marrow stromal cells

Progenitor cell therapies for traumatic brain injury: barriers and opportunities in translation

Traumatic brain injury (TBI) directly affects nearly 1.5 million new patients per year in the USA, adding to the almost 6 million cases in patients who are permanently affected by the irreversible physical, cognitive and psychosocial deficits from a prior injury. Adult stem cell therapy has shown preliminary promise as an option for treatment, much of which is limited currently to supportive care. Preclinical research focused on cell therapy has grown significantly over the last decade. One of the challenges in the translation of this burgeoning field is interpretation of the promising experimental results obtained from a variety of cell types, injury models and techniques. Although these variables can become barriers to a collective understanding and to evidence-based translation, they provide crucial information that, when correctly placed, offers the opportunity for discovery. Here, we review the preclinical evidence that is currently guiding the translation of adult stem cell therapy for TBI.

Why are MSCs therapeutic? New data: new insight

Adult marrow-derived mesenchymal stem cells (MSCs) are able to differentiate into bone, cartilage, muscle, marrow stroma, tendon-ligament, fat and other connective tissues. The questions can be asked, what do MSCs do naturally and where is the MSC niche? New insight and clinical experience suggest that MSCs are naturally found as perivascular cells, summarily referred to as pericytes, which are released at sites of injury, where they secrete large quantities of bioactive factors that are both immunomodulatory and trophic. The trophic activity inhibits ischaemia-caused apoptosis and scarring while stimulating angiogenesis and the mitosis of tissue intrinsic progenitor cells. The immunomodulation inhibits lymphocyte surveillance of the injured tissue, thus preventing autoimmunity, and allows allogeneic MSCs to be used in a variety of clinical situations. Thus, a new, enlightened era of experimentation and clinical trials has been initiated with xenogenic and allogeneic MSCs.

VEGF expression by mesenchymal stem cells contributes to angiogenesis in pancreatic carcinoma

Little is known about the factors that enable the mobilisation of human mesenchymal stem cells (MSC) from the bone marrow into the blood stream and their recruitment to and retention in the tumour. We found specific migration of MSC towards growth factors present in pancreatic tumours, such as PDGF, EGF, VEGF and specific inhibitors Glivec, Erbitux and Avastin interfered with migration. Within a few hours, MSC migrated into spheroids consisting of pancreatic cancer cells, fibroblasts and endothelial cells as measured by time-lapse microscopy. Supernatant from subconfluent MSC increased sprouting of HUVEC due to VEGF production by MSC itself as demonstrated by RT-PCR and ELISA. Only few MSCs were differentiated into endothelial cells in vitro, whereas in vivo differentiation was not observed. Lentiviral GFP-marked MSCs, injected in nude mice xenografted with orthotopic pancreatic tumours, preferentially migrated into the tumours as observed by FACS analysis of green fluorescent cells. By immunofluorescence and intravital microscopic studies, we found the interaction of MSC with the endothelium of blood vessels. Mesenchymal stem cells supported tumour angiogenesis in vivo, that is CD31⁺ vessel density was increased after the transfer of MSC compared with siVEGF-MSC. Our data demonstrate the migration of MSC toward tumour vessels and suggest a supportive role in angiogenesis.

Transplanted bone marrow stromal cells migrate, differentiate and improve motor function in rats with experimentally induced cerebral stroke

Bone marrow stromal cells are multipotential cells that can be induced to differentiate into osteoblasts, chondrocytes, myocytes and adipocytes in different microenvironments. Recent studies revealed that bone marrow stromal cells could improve neurological deficits of various damages or diseases of the central nervous system such as Parkinson's disease, brain trauma, spinal cord injury and multiple sclerosis, and promote glia-axonal remodeling in animal brain subjected to an experimentally induced stroke. In the present study, bone marrow stromal cells were intracerebrally transplanted into the cerebrum following a transient middle cerebral artery occlusion. Our aim was to find out whether the bone marrow stromal cells could survive and express neural phenotypic proteins and, in addition, whether they could restore the behavioral and functional deficits of the cerebral ischemic rats. Our results demonstrated that transplanted bone marrow stromal cells survived and migrated to areas around the lesion site. Some of them exhibited marker proteins of astrocytes and oligodendrocytes. Bone marrow stromal cell implantation significantly reduced the transient middle cerebral artery occlusion-induced cortical loss and thinning of the white matter and enhanced cortical beta-III-tubulin immunoreactivity. Rats implanted with bone marrow stromal cells showed significant improvement in their performance of elevated body swing test and forelimb footprint analysis and only transient recovery of the adhesive-removal test. Our data support bone marrow stromal cells as a valuable source of autologous or allogenic donor cells for transplantation to improve the outcome following cerebral ischemia.

Gene expression alterations of neurotrophins, their receptors and prohormone convertases in a rat model of spinal cord contusion

We have used a semi-quantitative RT-PCR approach to investigate the alterations in the expression of the main regulators of neuronal survival and death, neurotrophins (NTs), NT receptors, and prohormone convertases (PC), in a rat model of spinal cord contusion. Our results revealed that the expression of the members of NT family (Nerve-Growth Factor (NGF), Brain-Derived Neurotrophic Factor (BDNF), and Neurotrophin-3 (NT-3)) is significantly declined in the injured spinal cord, as early as 6h after the induction of the contusion. The expression was recovered afterward to that of the control levels. Furthermore, the expression of all NTs high-affinity Trk receptors decreased severely after the contusion. While the expression of TrkA and TrkC were completely shut down after 6 and 12h after injury respectively, the expression of TrkB receptor declined at 12h after injury and remained at this low level thereafter. In contrast to the pattern of Trk receptor expression, p75NTR receptor showed a significant upregulation after contusion. The expression of PC members functioning in the constitutive secretory pathway, i.e. furin, PACE4 and PC7, increased after damage, while the expression of PC members acting in regulated secretory pathway, PC1 and PC2, reduced after spinal cord injury. All together, the down-regulation of NTs, their designated Trk receptors and PC1/PC2 enzymes along with an upregulation of p75NTR promote neuronal death after injury. Our results suggest that either overexpression of NTs, Trk receptors and PC1/PC2 or interfering with the expression of p75NTR in host and/or grafted cells before transplantation could increase the success of the transplantation.

Mannitol enhances delivery of marrow stromal cells to the brain after experimental intracerebral hemorrhage

Previous studies show that intravascular injection of human bone marrow stromal cells (hBMSCs) significantly improves neurological functional recovery in a rat model of intracerebral hemorrhage (ICH). In the present study, we tested the hypothesis that mannitol improves the efficiency of intraarterial MSC delivery (i.e., fewer injected cells required for therapeutic efficacy) after ICH. There were four post-ICH groups (N=9): group 1, negative control with only intraarterial injection of 1 million human fibroblasts in phosphate-buffered saline (PBS); group 2, intravenous injection of mannitol alone in PBS (1.5 g/kg); group 3, intraarterial injection of 1 million hBMSCs alone in PBS; and group 4, intravenous injection of mannitol (1.5 g/kg) in PBS followed by intraarterial injection of 1 million hBMSCs in PBS. Group 4 exhibited significantly improved neurological functional outcome as assessed by neurological severity score (NSS) and corner test scores. Immunohistochemical staining of group 4 suggested increased synaptogenesis, proliferating immature neurons, and neuronal migration. The number of hBMSCs recruited to the injured region increased strikingly in group 4. Tissue loss was notably reduced in group 4. In summary, the beneficial effects of intraarterial infusion of MSCs are amplified with intravenous injection of mannitol. Preadministration of mannitol significantly increases the number of hBMSCs located in the ICH region, improves histochemical parameters of neural regeneration, and reduces the anatomical and pathological consequences of ICH.

A combined procedure to deliver autologous mesenchymal stromal cells to patients with traumatic brain injury

BACKGROUND

There is increasing evidence of therapeutic benefits from bone marrow (BM)-derived mesenchymal stromal cells (MSC) in various animal models with neurologic disorders. It is of great interest to apply the approach to clinical patients, i.e. to take the investigations from laboratory bench to the patient's bedside. This clinical trial was performed to assess the safety and feasibility of a combined procedure to deliver autologous MSC to patients with traumatic brain injury.

METHODS

MSC were isolated by BM aspiration and expanded in culture. Seven patients received autologous cell transplantation. A primary administration of 10(7)-10(9) cells was applied directly to the injured area during the cranial operation; a second dose of 10(8)-10(10) cells was infused intravenously. All patients were followed up regularly for 6 months.

RESULTS

There was no immediate or delayed toxicity related to the cell administration within the 6-month follow-up period. Neurologic function was significantly improved at 6 months after cell therapy.

DISCUSSION

The procedure used is safe and feasible at ordinary medical facilities without additional invasive procedures for the patient. The combined cell delivery procedure is expected to enhance the engraftment efficacy of transplanted cells at injured brain tissue, thereby promoting neurologic recover.

Cell therapies for traumatic brain injury

Preliminary discoveries of the efficacy of cell therapy are currently being translated to clinical trials. Whereas a significant amount of work has been focused on cell therapy applications for a wide array of diseases, including cardiac disease, bone disease, hepatic disease, and cancer, there continues to be extraordinary anticipation that stem cells will advance the current therapeutic regimen for acute neurological disease. Traumatic brain injury is a devastating event for which current therapies are limited. In this report the authors discuss the current status of using adult stem cells to treat traumatic brain injury, including the basic cell types and potential mechanisms of action, preclinical data, and the initiation of clinical trials.

Treatment of traumatic brain injury in mice with marrow stromal cells

This study was designed to investigate the potential beneficial effects of bone marrow stromal cell (MSC) treatment of traumatic brain injury (TBI) in mice. Twelve female C57BL/6J mice (weight, 21-26 g) were injured with controlled cortical impact and divided into 2 groups (n=6 each). The experimental group was injected with MSCs (0.3x10(6)) intravenously one day after TBI, whereas the control group was injected with saline. MSCs were harvested from male mice, and male to female transplantation was performed to identify male donor cells within female recipient animals. This was achieved by localizing Y chromosomes within the female mice. Neurological function was assessed using the Morris water maze and foot fault tests. All mice were sacrificed 35 days after TBI. Brain sections were stained using in situ hybridization and immunohistochemistry to identify MSCs as well as to analyze vascular density following MSC treatment. Both modalities of testing demonstrated significant improvement in neurological function in the MSC-treated group compared to the saline-treated control group (p<0.05). Histologically, Y chromosome labeled MSCs were easily identified in the injured brain, localized primarily around the lesion boundary zone. There was also a significant increase in vascular density in the lesion boundary zone and hippocampus of MSC-treated mice compared to control mice. This is the first study to show beneficial effects of MSC treatment after TBI in mice.

Disparate host response and donor survival after the transplantation of mesenchymal or neuroectodermal cells to the intact rodent brain

BACKGROUND

To circumvent ethical and legal complications associated with embryonic cell sources, investigators have proposed the use of nonneural donor sources for use in neural transplantation strategies. Leading candidate sources include autologous marrow stromal cells (MSCs) and fibroblasts, which are mesodermal derivatives. However, we recently reported that MSCs transplanted to the adult brain are rapidly rejected by an inflammatory response. Whether extrinsic variables or intrinsic mesenchymal traits stimulated inflammation and rejection is unknown. To determine the future utility of these cells in neural transplantation, we have now performed a systematic analysis of MSC transplantation to the brain.

METHODS

To examine the effects of extrinsic variables on transplantation, green fluorescent protein (GFP)-expressing rat MSCs, cultured under distinct conditions, were transplanted stereotactically to the normal adult rat striatum, and donor survival and the host response was compared. To examine whether intrinsic donor traits promoted rejection, 50,000 GFP-expressing rat MSCs, fibroblasts, or astrocytes were transplanted stereotactically to the adult rat striatum and graft survival and the host response was compared.

RESULTS

Irrespective of preoperative culture conditions, MSCs elicited an inflammatory response and were rejected by 14 days, indicating acute rejection was not mediated by culture conditions. Comparison of MSC, fibroblast, or astrocyte grafts revealed that mesenchymal derivatives, MSCs and fibroblasts, elicited an inflammatory response and were rapidly rejected, whereas neuroectodermal astrocytes demonstrated robust survival in the absence of inflammation.

CONCLUSIONS

Our findings suggest that intrinsic characteristics of mesenchymal cells may stimulate host inflammation, and thus may not represent an ideal donor source for transplantation to the adult brain.

In vivo bioimaging using photogenic rats: fate of injected bone marrow-derived mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) derived from bone marrow have the capacity for self-renewal and differentiation, and can give rise to cells of a muscle, bone, fat or cartilage lineage. Based on this potential and feasibility, MSCs are expected to be used in cell therapy for human diseases. Intriguingly, MSCs migrate to various in vivo locations, including injury and tumor sites. However, their cellular fate and distribution remain unclear. In this review, we first describe the potential of a photogenic transgenic rat that expresses fluorescent and/or luminescent proteins (e.g., green fluorescent protein and luciferase), and then focus on the characteristic migration of MSCs to injury and tumor sites. In addition, we will discuss an efficient delivery method for targeting the injured site. Synergized with modern advances in optical imaging, the photogenic rat system provides innovative preclinical tools and a new platform on which to further our understanding of matters concerning stem cell biology.

Improved lentiviral transduction of human mesenchymal stem cells for therapeutic intervention in pancreatic cancer

Genetic modification of human bone marrow mesenchymal stem cells (MSC) is highly valuable for their exploitation in basic science and therapeutic applications, for example in cancer. We present here a new, fast and easy-to-use method to enrich a functional population of lentiviral (LV)-transduced MSC expressing enhanced green fluorescent protein (eGFP). We replaced the eGFP gene by a fusion gene of puromycin acetyltransferase and eGFP. Upon LV gene transfer and puromycin selection, we quickly obtained a pure transduced MSC population, in which growth, differentiation capacity and migration preferences were not compromised. Furthermore, we are the first to report the migration velocity of MSC among which 30% were moving and velocity of about 15 mum h(-1) was not altered by LV transduction. Manipulated MSC underwent senescence one passage earlier than non-transduced cells, suggesting the use for therapeutic intervention in early passage numbers. Upon tail vein application in nude mice, the majority of LV-transduced MSC could be detected in human orthotopic pancreatic tumor xenografts and to a minor extent in mouse liver, kidney and lung. Together, LV transduction of genes to MSC followed by puromycin selection is a powerful tool for basic research and improves the therapeutic prospects of MSC as vehicles in gene therapy.

[Evaluation of tongue manifestation of blood stasis syndrome and its relationship with blood rheological disorder in a rat model of transient brain ischemia]

OBJECTIVE

To study the tongue tissue blood oxygen saturation measurement for evaluating tongue manifestation of blood stasis syndrome, and to explore its correlation with blood rheological disorder in a rat model of acute transient brain ischemia.

METHODS

Twenty-eight SD rats were randomly divided into sham-operated group and ischemia group. Middle cerebral artery occlusion was induced by thread in rats of the ischemia group. Tongue tissue blood oxygen saturation, neurological severity score and the changes of blood viscosity, red blood cell deformity, thrombin time and fibrinogen in the rats were measured after 24-hour reperfusion.

RESULTS

Blood viscosity and the content of fibrinogen in the ischemia group were significantly higher than those in the sham-operated group. Red blood cell deformity, thrombin time and tongue tissue blood oxygen saturation in the ischemia group were decreased as compared with the sham-operated group. There was a positive correlation between red blood cell deformity and tongue tissue blood oxygen saturation.

CONCLUSION

Tongue tissue blood oxygen saturation is a good measurement for evaluating blood stasis in a rat model of focal cerebral ischemia, and this model can be used as a rat model of stroke with blood stasis syndrome.

Protection of dopamine neurons by bone marrow stromal cells

Transplantation of bone marrow stromal cells (BMSC) has recently been demonstrated to provide neuroprotection in animal models of brain injuries such as ischemia and trauma. The present study was undertaken to explore whether BMSC can promote the survival of dopamine (DA) neurons in neuronal insult models in vitro. We also examined whether BMSC can increase the survival rate of embryonic DA neurons grafted into the striatum of a rat model of Parkinson's disease (PD). Treatment with conditioned media derived from BMSC cultures was found to significantly prevent the death of DA neurons in in vitro cell injury models such as serum deprivation and exposure to the neurotoxin 6-OHDA. In a transplantation study, we also found that the survival of grafted DA cells was significantly enhanced by treating donor cells with the conditioned media at the steps of both cell dissociation and implantation. The results suggest that BMSC may secrete diffusible factors able to protect DA neurons against neuronal injuries. Indeed, BMSC expressed mRNA encoding brain-derived neurotrophic factor, fibroblast growth factor-2 and glial cell line-derived neurotrophic factor, all of which have previously been shown to exhibit potent neurotrophic effects on DA cells. Enzyme-linked immunosorbent assay revealed that the cells release these growth factors into culture media. The present data indicate that BMSC may be a potential donor source of cell-based regenerative therapy for PD where the progressive loss of the midbrain DA neurons takes place.

Therapeutic time window and effect of intracarotid neural stem cells transplantation for intracerebral hemorrhage

This study investigated the therapeutic effect of neural stem cells transplanted via the carotid artery at different times after intracerebral hemorrhage. A great number of 5-bromo-2-deoxyuridine-positive cells were observed surviving and distributed evenly in the perihematoma areas. Phenotypes of grafted cells depended upon time of transplantation, and the later the cells were transplanted, the larger the percentage of cells that differentiated into neurons. Animals treated at 7 and 14 days after injury exhibited the most significant improvements in behavioral tests. Therefore,intracarotid injection allows efficient delivery of cells to the injured hemisphere, especially during the period 7-14 days after injury, and may potentially be applicable in humans.

Concise review: mesenchymal stem cells: their phenotype, differentiation capacity, immunological features, and potential for homing

MSCs are nonhematopoietic stromal cells that are capable of differentiating into, and contribute to the regeneration of, mesenchymal tissues such as bone, cartilage, muscle, ligament, tendon, and adipose. MSCs are rare in bone marrow, representing approximately 1 in 10,000 nucleated cells. Although not immortal, they have the ability to expand manyfold in culture while retaining their growth and multilineage potential. MSCs are identified by the expression of many molecules including CD105 (SH2) and CD73 (SH3/4) and are negative for the hematopoietic markers CD34, CD45, and CD14. The properties of MSCs make these cells potentially ideal candidates for tissue engineering. It has been shown that MSCs, when transplanted systemically, are able to migrate to sites of injury in animals, suggesting that MSCs possess migratory capacity. However, the mechanisms underlying the migration of these cells remain unclear. Chemokine receptors and their ligands and adhesion molecules play an important role in tissue-specific homing of leukocytes and have also been implicated in trafficking of hematopoietic precursors into and through tissue. Several studies have reported the functional expression of various chemokine receptors and adhesion molecules on human MSCs. Harnessing the migratory potential of MSCs by modulating their chemokine-chemokine receptor interactions may be a powerful way to increase their ability to correct inherited disorders of mesenchymal tissues or facilitate tissue repair in vivo. The current review describes what is known about MSCs and their capacity to home to tissues together with the associated molecular mechanisms involving chemokine receptors and adhesion molecules.

Human umbilical cord blood-derived CD34+ cells cause attenuation of multiorgan dysfunction during experimental heatstroke

Multiorgan dysfunction ensuing from severe heatstroke includes hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. We attempted to assess whether human umbilical cord blood-derived CD34+ cell therapy improves survival during experimental heatstroke by attenuating multiorgan dysfunction. Anesthetized rats, immediately after the onset of heatstroke, were divided into 2 major groups and given CD34- or CD34+ cells (1 x 10(5)-5 x 10(5)/mL/kg body weight) i.v. They were exposed to ambient temperature of 43 degrees C to induce heatstroke. Another group of rats were exposed to room temperature (26 degrees C) and used as normothermic controls. Hypotension, hepatic and renal failure (evidenced by increased serum urea nitrogen, creatinine, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase levels in plasma), hypercoagulable state (evidenced by increased prothrombin time, activated partial thromboplastin time, and D-dimer, and decreased platelet count and protein C in plasma), activated inflammation (evidence by increased TNF-alpha levels in serum), and cerebral dysfunction (evidenced by intracranial hypertension, cerebral hypoperfusion and hypoxia, and cerebral ischemia and injury) were monitored. When the CD34- cell-treated or untreated rats underwent heat stress, their survival time values were found to be 19 to 23 min. Resuscitation with CD34+ cells significantly improved survival time (duration, 63-291 min). As compared with normothermic controls, all CD34- cell-treated heatstroke animals displayed hypotension, hepatic and renal failure, hypercoagulable state, activated inflammation, and cerebral ischemia and injury. However, CD34+ cell therapy significantly caused attenuation of all the above-mentioned heatstroke reactions. In addition, the levels of IL-10 in plasma and glial cell line-derived neurotrophic factors in brain were all significantly increased after CD34+ cell therapy during heatstroke. Our data indicate that CD34+ cell therapy may resuscitate persons who had a heatstroke by reducing multiorgan dysfunction or failure.

Bone marrow-derived mesenchymal stromal cells for the repair of central nervous system injury

Transplantation of bone marrow-derived mesenchymal stromal cells (MSCs) into the injured brain or spinal cord may provide therapeutic benefit. Several models of central nervous system (CNS) injury have been examined, including that of ischemic stroke, traumatic brain injury and traumatic spinal cord injury in rodent, primate and, more recently, human trials. Although it has been suggested that differentiation of MSCs into cells of neural lineage may occur both in vitro and in vivo, this is unlikely to be a major factor in functional recovery after brain or spinal cord injury. Other mechanisms of recovery that may play a role include neuroprotection, creation of a favorable environment for regeneration, expression of growth factors or cytokines, vascular effects or remyelination. These mechanisms are not mutually exclusive, and it is likely that more than one contribute to functional recovery. In light of the uncertainty surrounding the fate and mechanism of action of MSCs transplanted into the CNS, further preclinical studies with appropriate animal models are urgently needed to better inform the design of new clinical trials.

Proprotein convertases 1 and 2 (PC1 and PC2) are expressed in neurally differentiated rat bone marrow stromal stem cells (BMSCs)

Neural-like cells derived from bone marrow stromal stem cells (BMSCs) have potential usefulness in cell therapy of degenerative or traumatic diseases of the central nervous system (CNS). The functional recovery mediated by these cells, however, depends on the secretion of neurotrophins (NTs) and their cognate receptors, as the main regulators of neural survival and death. The function of NTs is further modulated by proprotein convertase (PC) enzymes which function in converting proproteins (including proNTs) into their functional end products. Accordingly, failure in converting proprotein forms of NTs into their mature forms may lead to neuronal cell death. In the present study, we have investigated the expression profile of PCs before and during neural differentiation of rat BMSCs by RT-PCR. Our results show that major members of the PC family functioning in the constitutive secretory pathway (furin, PACE4 and PC7/LPC) are highly expressed in both undifferentiated and neurally differentiated BMSCs. In contrast, while PC1/PC3 and PC2 (specific to neural and endocrine cells) are absent in undifferentiated BMSCs, their expression is initiated upon the induction of differentiation. In conclusion, our results suggest that neurally differentiated BMSCs have acquired the functional machinery to process the precursor forms of proteins in both the constitutive and regulated pathways.

Treatment of traumatic brain injury with a combination therapy of marrow stromal cells and atorvastatin in rats

OBJECTIVE

This study investigated the effects of a combination therapy of marrow stromal cells (MSCs) and statins (atorvastatin) after traumatic brain injury in rats.

METHODS

Thirty-two female Wistar rats were injured by controlled cortical impact and divided into four groups. Group I was injected with MSCs (1 x 10(6)) intravenously 24 hrs after traumatic brain injury. Group II was administered atorvastatin (0.5 mg/kg) orally for 14 days starting 24 hours after traumatic brain injury. Group III received MSCs (1 x 10(6)) combined with atorvastatin (0.5 mg/kg). Group IV (control) was injected with saline. MSCs were harvested from the bone marrow of male rats to identify male donor cells within female recipient animals by localization of Y chromosomes. Functional analysis was performed using modified neurological severity scores and the Morris water maze test. Animals were sacrificed 35 days after injury and brain sections stained with immunohistochemistry.

RESULTS

No functional improvement was seen in animals treated with MSCs or atorvastatin alone (Groups I and II). However, functional improvement was seen with both testing modalities (modified neurological severity scores and Morris water maze) in animals receiving combination therapy (Group III). Microscopic analysis showed that significantly more MSCs were present in animals receiving combination therapy than in those receiving MSCs alone. Also, significantly more endogenous cellular proliferation was seen in the hippocampus and injury boundary zone of the combination therapy group than in the monotherapy or control groups.

CONCLUSION

When administered in combination with MSCs, atorvastatin increases MSC access and/or survival within the injured brain and enhances functional recovery compared with monotherapy.

Bone marrow-derived stem cells in neurological diseases: stones or masons?

In spite of the commonly held belief that ‘the brain does not regenerate’, it is now accepted that postnatal neurogenesis does occur. Thus, one wonders whether cellular-replacement therapy might be used to heal the brain in diseases caused by neuronal cell loss. The existence of neural stem cells has been demonstrated by many scientists and is now generally accepted. The exact role of these cells, how their numbers are regulated and how they participate in CNS and spinal cord regeneration in postnatal life are still not well known. There are many reviews summarizing work on these cells; consequently, I will focus instead on other cells that may participate in postnatal neurogenesis: bone marrow-derived stem cells. The possibility that bone marrow-derived stem cells populate the CNS and differentiate into various neural elements is certainly not universally accepted.

Embryonic stem cells produce neurotrophins in response to cerebral tissue extract: Cell line-dependent differences

In the present study, we compare the capacity of two different embryonic stem (ES) cell lines to secrete neurotrophins in response to cerebral tissue extract derived from healthy or injured rat brains. The intrinsic capacity of the embryonic cell lines BAC7 (feeder cell-dependent cultivation) to release brain-derived neurotrophic factor (BDNF) or neurotrophin-3 (NT-3) exceeded the release of these factors by CGR8 cells (feeder cell-free growth) by factors of 10 and 4, respectively. Nerve growth factor (NGF) was secreted only by BAC7 cells. Conditioning of cell lines with cerebral tissue extract derived from healthy or fluid percussion-injured rat brains resulted in a significant time-dependent increase in BDNF release in both cell lines. The increase in BDNF release by BAC7 cells was more pronounced when cells were incubated with brain extract derived from injured brain. However, differences in neurotrophin release associated with the origin of brain extract were at no time statistically significant. Neutrophin-3 and NGF release was inhibited when cell lines were exposed to cerebral tissue extract. The magnitude of the response to cerebral tissue extract was dependent on the intrinsic capacity of the cell lines to release neurotrophins. Our results clearly demonstrate significant variations in the intrinsic capability of different stem cell lines to produce neurotrophic factors. Furthermore, a significant modulation of neurotrophic factor release was observed following conditioning of cell lines with tissue extract derived from rat brains. A significant modulation of neurotrophin release dependent on the source of cerebral tissue extract used was not observed.

Differential gene expression associated with migration of mesenchymal stem cells to conditioned medium from tumor cells or bone marrow cells

Distinct signals that guide migration of mesenchymal stem cells (MSCs) to specific in vivo targets remain unknown. We have used rat MSCs to investigate the molecular mechanisms involved in such migration. Rat MSCs were shown to migrate to tumor microenvironment in vivo, and an in vitro migration assay was used under defined conditions to permit further mechanistic investigations. We hypothesized that distinct molecular signals are involved in the homing of MSCs to tumor sites and bone marrow. To test this hypothesis, gene expression profiles of MSCs exposed in vitro to conditioned medium (CM) from either tumor cells or bone marrow were compared. Analysis of the microarray gene expression data revealed that 104 transcripts were upregulated in rat MSCs exposed to CM from C85 human colorectal cancer cells for 24 hours versus control medium. A subset of 12 transcripts were found to be upregulated in rat MSCs that were exposed to tumor cell CM but downregulated when MSCs were exposed to bone marrow CM and included CXCL-12 (stromal cell-derived factor-1 [SDF-1]), CXCL-2, CINC-2, endothelial cell specific molecule-1, fibroblast growth factor-7, nuclear factor-kappaB p105, and thrombomodulin. Exposure to tumor cell CM enhanced migration of MSCs and correlated with increased SDF-1 protein production. Moreover, knockdown of SDF-1 expression in MSCs inhibited migration of these cells to CM from tumor cells, but not bone marrow cells, confirming the importance of SDF-1 expression by MSCs in this differential migration. These results suggest that increased SDF-1 production by MSCs acts in an autocrine manner and is required for migratory responses to tumor cells.

Human marrow stromal cell treatment provides long-lasting benefit after traumatic brain injury in rats

OBJECTIVE

This study was designed to investigate the effects of human bone marrow stromal cell (hMSC) administration in rats for 3 months after traumatic brain injury (TBI).

METHODS

Adult male Wistar rats (n = 60) were injured with controlled cortical impact and divided into four groups. The three treatment groups (n = 10 each) were injected with 2 x 10, 4 x 10, and 8 x 10 hMSCs, respectively, intravenously, whereas the control group (n = 30) received phosphate-buffered saline. All injections were performed 1 day after injury into the tail veins of rats. Neurological functional evaluation of animals was performed before and after injury by use of Neurological Severity Scores. Animals were sacrificed 3 months after TBI, and brain sections were stained by immunohistochemistry.

RESULTS

Statistically significant improvement in functional outcome was observed in all three treatment groups compared with control values (P < 0.05). This benefit was visible 14 days after TBI and persisted until 3 months (end of trial). There was no difference in functional outcome among the three treatment groups. Histological analysis showed that hMSCs were present in the lesion boundary zone at 3 months with all three doses tested.

CONCLUSION

hMSCs injected in rats after TBI survive until 3 months and provide long-lasting functional benefit. Functional improvement may be attributed to stimulation of endogenous neurorestorative functions such as neurogenesis and synaptogenesis.

Cell therapy using bone marrow stromal cells in chronic paraplegic rats: Systemic or local administration?

Recent studies showed the therapeutic effect of bone marrow stromal cells (BMSC) after spinal cord injury (SCI). In the present study, we compared the effect of systemic and local administration of BMSC in adult Wistar rats suffering chronic paraplegia as consequence of severe SCI. Adult Wistar rats were subjected to a weight-drop impact causing complete paraplegia, and 3 months later, all the animals remained without signs of functional recovery. At this moment, 3 x 10(6) BMSC were injected intravenously (n: 20) or into traumatic spinal cord cavity (n: 20). Outcome was evaluated until sacrifice of the animals, 6 months later, using the Basso-Beattie-Bresnehan (BBB) score, the cold spray test, and measuring the thigh perimeter. After sacrifice, samples of spinal cord tissue were studied histologically. The results showed that intravenous administration of BMSC achieves some degree of functional recovery when compared to controls. Nevertheless, administration of BMSC into postraumatic spinal cord cavity promotes a clear and progressive functional recovery, significantly superior to the recovery obtained by means of the intravenous administration. This effect is associated to long-term presence of BMSC in the injured spinal cord tissue, with images suggesting neuronal differentiation and spinal cord reconstruction.

Differential gene expression pattern of neurotrophins and their receptors during neuronal differentiation of rat bone marrow stromal cells

Neural-like cells derived from bone marrow stromal cells (BMSC) have potential usefulness in repair of the CNS injuries or diseases. The functional recovery mediated by these cells, however, depends on secretion of specific growth factors and their designated receptors. In the present study, we have investigated the expression profile of neurotrophins NGF, BDNF and NT-3 and their high-affinity (TrkA, TrkB, TrkC) and common low-affinity (p75NTR) receptors before and during neural differentiation of rat BMSCs by RT-PCR. Results indicate that NGF and BDNF but not NT-3 are expressed in both un-differentiated as well as neurally differentiated BMSCs. In contrast, the expression of TrkA and TrkB is restricted to neurally differentiated cells, while TrkC is not expressed in these cells either before or after differentiation. Interestingly, p75NTR expression is absent in un-differentiated cells but is initiated upon the induction of neural differentiation, and then shut off in fully differentiated neuron-like cells.

Long-term recovery after bone marrow stromal cell treatment of traumatic brain injury in rats

OBJECT

This study was designed to follow the effects of bone marrow stromal cell (BMSC) administration in rats after traumatic brain injury (TBI) for a 3-month period.

METHODS

Forty adult female Wistar rats were injured by a controlled cortical impact and, 1 week later, were injected intravenously with one of three different doses of BMSCs (2 x 10(6), 4 x 10(6), or 8 x 10(6) cells per animal) obtained in male rats. Control rats received phosphate-buffered saline (PBS). Neurological function in these rats was studied using a neurological severity scale (NSS). The rats were killed 3 months after injury, and immunohistochemical stains were applied to brain samples to study the distribution of the BMSCs. Additional brain samples were analyzed by quantitative enzyme-linked immunosorbent assays to measure the expression of the growth factors brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Three months after injury, BMSCs were present in the injured brain and their number was significantly greater in animals that received 4 x 10(6) or 8 x 10(6) BMSCs than in animals that received 2 x 10(6) BMSCs. The cells were primarily distributed around the lesion boundary zone. Functional outcome was significantly better in rats that received 4 x 10(6) or 8 x 10(6) BMSCs, compared with control animals, although no improvement was seen in animals that received 2 x 10(6) BMSCs. All doses of BMSCs significantly increased the expression of BDNF but not that of NGF; however, this increase was significantly larger in animals that received 4 x 10(6) or 8 x 10(6) BMSCs than in controls or animals that received 2 x 10(6) BMSCs.

CONCLUSIONS

In summary, when injected in rats after TBI, BMSCs are present in the brain 3 months later and significantly improve functional outcome.

Fat tissue: an underappreciated source of stem cells for biotechnology

Adipose tissue can be harvested in large amounts with minimal morbidity. It contains numerous cells types, including adipocytes, preadipocytes, vascular endothelial cells and vascular smooth muscle cells; it also contains cells that have the ability to differentiate into several lineages, such as fat, bone, cartilage, skeletal, smooth, and cardiac muscle, endothelium, hematopoietic cells, hepatocytes and neuronal cells. Cloning studies have shown that some adipose-derived stem cells (ADSCs) have multilineage differentiation potential. ADSCs are also capable of expressing multiple growth factors, including vascular endothelial growth factor and hepatocyte growth factor. Early, uncontrolled, non-randomized clinical research, applying fresh adipose-derived cells into a cranial defect or undifferentiated ADSCs into fistulas in Crohn's disease, has shown healing and an absence of side effects. The combination of these properties, and the large quantity of cells that can be obtained from fat, suggests that this tissue will be a useful tool in biotechnology.

Effects of intravenous administration of human bone marrow stromal cells after intracerebral hemorrhage in rats

Object

The goal of this study was to investigate whether human bone marrow stromal cells (hBMSCs) administered by intravenous injection have a beneficial effect on outcome after intracerebral hemorrhage (ICH) in rats.

Methods

An ICH was induced in 54 adult male Wistar rats by a stereotactically guided injection of autologous blood into the right striatum. Intravenous infusion of the hBMSCs (3, 5, or 8 million cells) was performed 1 day after ICH, and for each dose group there was a control group that received injections of vehicle. Neurological function, which was evaluated using the Neurological Severity Score (NSS) and the corner turn test, was tested before and at 1, 7, and 14 days after ICH. After 14 days of survival, the area of encephalomalacia was calculated and histochemical labeling was performed.

For all three groups, there were no statistical differences in either the NSS or corner turn tests after 1 day. After 7 and 14 days, however, the three groups that received the hBMSCs showed significant improvement in functional scores compared with the control group. In addition, after 14 days there was significantly more striatal tissue loss in the placebo groups compared with each of the three treatment groups. The region of injury in the treated animals demonstrated a significantly increased presence of hBMSCs, immature neurons, neuronal migration, synaptogenesis, and newly formed DNA.

Conclusions

Intravenous administration of hBMSCs significantly improves neurological function in rats subjected to ICH. This improvement in the treated animals is associated with reduced tissue loss and increased local presence of the hBMSCs, mitotic activity, immature neurons, synaptogenesis, and neuronal migration.

Transplantation of Undifferentiated, Bone Marrow‐Derived Stem Cells

Stem cell research has known an enormous development, and cellular transplantation holds great promise for regenerative medicine. However, some aspects, such as the mechanisms underlying stem cell plasticity (cell fusion vs true transdifferentiation) and the functional improvement after stem cell transplantation, are highly debated. Furthermore, the great variability in methodology used by several groups, sometimes leads to confusing, contradicting results. In this chapter, we review a number of studies in this area with an eye on possible technical and other difficulties in interpretation of the obtained results.

Lumbar Puncture Delivery of Bone Marrow Stromal Cells in Spinal Cord Contusion: A Novel Method for Minimally Invasive Cell Transplantation

Cell transplantation as a treatment for spinal cord injury is a promising therapeutic strategy whose effective clinical application would be facilitated by non-invasive delivery protocols. Cells derived from the bone marrow are particularly attractive because they can be obtained easily, expanded to large numbers and potentially used for autologous as well as allogeneic transplantation. In this study we tested the feasibility of a novel minimally invasive method--lumbar puncture (LP)--for transplanting bone marrow stromal stem cells (MSC) into a clinically relevant spinal cord contusion model. We further sought to determine optimal protocols for performing such minimally invasive cell transplantation. Sprague-Dawley rats received a moderate contusion injury at the midthoracic level followed by LP transplantation of MSC derived from transgenic rats that express the human placental alkaline phosphatase (AP) reporter gene. The recipients were analyzed histologically to evaluate the extent of cell delivery and survival at the injury site. We found that MSC delivered by LP reached the contused spinal cord tissues and exerted a significant beneficial effect by reducing cyst and injury size. Transplantation within 14 days of injury provided significantly greater grafting efficiency than more delayed delivery, and increasing MSC dosage improved cell engraftment. The techniques described here can easily be translated to patients, thus accelerating clinical application of stem cell therapies.

The behavioral effect of human mesenchymal stem cell transplantation in cold brain injured rats

We investigated the effect of stereotaxically transplanted human mesenchymal stem cells (hMSCs) on behavioral change after traumatic cold brain injury in adult rats. Cortical lesions (n= 20) were induced by touching a metal stamp, cooled with liquid nitrogen, to the dura over the forelimb motor cortex of adult rats. The procedure produced a localized lesion, and the animals showed significant motor deficits. hMSCs were freshly isolated from human iliac bone and cultured in tissue culture flasks with 10 ml Dulbecco's modified Eagle's medium. The animals received hMSC grafts (3 x 10(5) hMSCs) 6 days after cold lesion (n = 10). All rats were sacrificed 3 or 7 weeks after cold injury, and immunohistochemical staining was performed on brain sections to identify donor hMSCs. Neurological evaluations were performed with the forepaw adjusting step test and modified neurological scoring. Treatment with 3 x 10(5) hMSCs improved the rat's neurological functions. We also found that the transplanted cells successfully migrated into the injured brain, preferentially localized around the injury site, and expressed the neuronal and astrocyte marker. These data suggest that hMSCs may be a potential therapeutic tool for brain injuries.

Human mesenchymal stem cell subpopulations express a variety of neuro-regulatory molecules and promote neuronal cell survival and neuritogenesis

Mesenchymal stem cells (MSCs) transplanted at sites of nerve injury are thought to promote functional recovery by producing trophic factors that induce survival and regeneration of host neurons. To evaluate this phenomenon further, we quantified in human MSCs neurotrophin expression levels and their effects on neuronal cell survival and neuritogenesis. Screening a human MSC cDNA library revealed expressed transcripts encoding BDNF and beta-NGF but not NT-3 and NT-4. Immunostaining demonstrated that BDNF and beta-NGF proteins were restricted to specific MSC subpopulations, which was confirmed by ELISA analysis of 56 separate subclones. Using a co-culture assay, we also demonstrated that BDNF expression levels correlated with the ability of MSC populations or subclones to induce survival and neurite outgrowth in the SH-SY5Y neuroblastoma cell line. However, these MSC-induced effects were only partially inhibited by a neutralizing anti-BDNF antibody. MSCs were also shown to promote neurite outgrowth within dorsal root ganglion explants despite secreting 25-fold lower level of beta-NGF required exogenously to produce a similar effect. Interrogation of the human MSC transcriptome identified expressed mRNAs encoding various neurite-inducing factors, axon guidance and neural cell adhesion molecules. Moreover, a subset of these transcripts was shown to correlate with BDNF expression in MSC subclones. Collectively, these studies reveal the existence of MSC subpopulations that co-express neurotrophins and other potent neuro-regulatory molecules, which contribute to MSC-induced effects on neuronal cell survival and nerve regeneration. These subpopulations may represent more potent vectors for treating a variety of neurological disorders.

Do bone marrow stromal cells proliferate after transplantation into mice cerebral infarct?—A double labeling study

The present study was aimed to clarify the proliferation capacity of the bone marrow stromal cells (BMSC) transplanted into the brain. The BMSC were harvested from green fluorescence protein (GFP)-transgenic mice, grown to the confluency and passed three times. They were labeled by co-culture with Ferucarbotran, a superparamagnetic iron oxide (SPIO) agent. The proportions of the SPIO-positive cells were evaluated from P3 to P7, using Turnbull blue staining. The GFP-BMSC labeled by Ferucarbotran were transplanted into the ipsilateral striatum of the mice brain subjected to permanent focal ischemia at 7 days after the insult. The distribution and differentiation of GFP- and SPIO-positive cells in the brain were studied 3 months after transplantation, using immunohistochemistry and Turnbull blue staining. As the results, the proportions of the SPIO-positive cells gradually decreased from 93.6% at P3 to 6.5% at P7. Fluorescence immunohistochemistry revealed that the GFP-positive cells were widely distributed around infarct and partially expressed MAP2 and NeuN 3 months after transplantation. However, only a smaller number of SPIO-positive cells could be detected on Turnbull blue staining. The ratio of the SPIO- to GFP-positive cells was approximately 2.7%. The results strongly suggest that the BMSC repeat proliferation many times, migrate into the lesion, and partially express the neuronal phenotype in the host brain during 3 months after transplantation. The double labeling technique would be valuable to prove the proliferation of the transplanted cells in the host tissue because GFP gene and SPIO nanoparticles have different inheritance characteristics.

Evaluation of the effect of transplant-related factors and tissue injury on donor-derived hepatocyte and gastrointestinal epithelial cell repopulation following hematopoietic cell transplantation

The aim of this study was to detect donor-derived hepatocytes and gastrointestinal epithelial cells in recipients of sex-mismatched allogeneic hematopoietic cell transplants, and to assess the effect of tissue injury on the extent of the repopulation. A total of 29 paraffin-embedded biopsy samples were reviewed. Double labeling by immunohistochemistry and fluorescence in situ hybridization was performed. Eighty-nine percent of sex-mismatched samples with histologic evidence of injury demonstrated the presence of donor-derived hepatocytes and gastrointestinal epithelial cells (mean 2.4%). None of the hepatocytes and gastrointestinal epithelial cells in samples obtained from female recipients with female donors showed a Y chromosome signal. The proportion of donor-derived hepatocyte and gastrointestinal epithelial cells in samples with severe graft-versus-host disease was greater than that of samples with mild/moderate graft-versus-host disease (P = 0.09). No relationship between the source of stem cells and the population rate was detected (P > 0.05). We conclude that some recipient hepatocytes and gastrointestinal tract epithelial cells are replaced by donor-derived cells during tissue injury. The severity of tissue injury seems to influence on the extent of this repopulation.

Review: mesenchymal stem cells: cell-based reconstructive therapy in orthopedics

Adult stem cells provide replacement and repair descendants for normal turnover or injured tissues. These cells have been isolated and expanded in culture, and their use for therapeutic strategies requires technologies not yet perfected. In the 1970s, the embryonic chick limb bud mesenchymal cell culture system provided data on the differentiation of cartilage, bone, and muscle. In the 1980s, we used this limb bud cell system as an assay for the purification of inductive factors in bone. In the 1990s, we used the expertise gained with embryonic mesenchymal progenitor cells in culture to develop the technology for isolating, expanding, and preserving the stem cell capacity of adult bone marrow-derived mesenchymal stem cells (MSCs). The 1990s brought us into the new field of tissue engineering, where we used MSCs with site-specific delivery vehicles to repair cartilage, bone, tendon, marrow stroma, muscle, and other connective tissues. In the beginning of the 21st century, we have made substantial advances: the most important is the development of a cell-coating technology, called painting, that allows us to introduce informational proteins to the outer surface of cells. These paints can serve as targeting addresses to specifically dock MSCs or other reparative cells to unique tissue addresses. The scientific and clinical challenge remains: to perfect cell-based tissue-engineering protocols to utilize the body's own rejuvenation capabilities by managing surgical implantations of scaffolds, bioactive factors, and reparative cells to regenerate damaged or diseased skeletal tissues.

Enhanced hippocampal neurogenesis by intraventricular S100B infusion is associated with improved cognitive recovery after traumatic brain injury

Evidence of injury-induced neurogenesis in the adult hippocampus suggests that an endogenous repair mechanism exists for cognitive dysfunction following traumatic brain injury (TBI). One factor that may be associated with this restoration is S100B, a neurotrophic/mitogenic protein produced by astrocytes, which has been shown to improve memory function. Therefore, we examined whether an intraventricular S100B infusion enhances neurogenesis within the hippocampus following experimental TBI and whether the biological response can be associated with a measurable cognitive improvement. Following lateral fluid percussion or sham injury in male rats (n = 60), we infused S100B (50 ng/h) or vehicle into the lateral ventricle for 7 days using an osmotic micro-pump. Cell proliferation was assessed by injecting the mitotic marker bromodeoxyuridine (BrdU) on day 2 postinjury. Quantification of BrdU-immunoreactive cells in the dentate gyrus revealed an S100B-enhanced proliferation as assessed on day 5 post-injury (p < 0.05), persisting up to 5 weeks (p < 0.05). Using cell-specific markers, we determined the relative numbers of these progenitor cells that became neurons or glia and found that S100B profoundly increased hippocampal neurogenesis 5 weeks after TBI (p < 0.05). Furthermore, spatial learning ability, as assessed by the Morris water maze on day 30-34 post-injury, revealed an improved cognitive performance after S100B infusion (p < 0.05). Collectively, our findings indicate that an intraventricular S100B infusion induces neurogenesis within the hippocampus, which can be associated with an enhanced cognitive function following experimental TBI. These observations provide compelling evidence for the therapeutic potential of S100B in improving functional recovery following TBI.

Protective effects of bone marrow stromal cell transplantation in injured rodent brain: synthesis of neurotrophic factors

Several groups have suggested that transplantation of marrow stromal cells (MSCs) promotes functional recovery in animal models of brain trauma. Recent studies indicate that tissue replacement by this method may not be the main source of therapeutic benefit, as transplanted MSCs have only limited ability to replace injured central nervous system (CNS) tissue. To gain insight into the mechanisms responsible for such effects, we systematically investigated the therapeutic potential of MSCs for treatment of brain injury. Using in vitro studies, we detected the synthesis of various growth factors, including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), and neurotrophin-3 (NT-3). Enzyme-linked immunosorbent assay (ELISA) demonstrated that MSCs cultured in Dulbecco's modified Eagle medium (DMEM) produced substantial amounts of NGF for at least 7 weeks, whereas the levels of BDNF, GDNF and NT-3 remained unchanged. In studies in mice, after intraventricular injection of MSCs, NGF levels were increased significantly in cerebrospinal fluid by ELISA, confirming our cell culture results. Further studies showed that treatment of traumatic brain injury with MSCs could attenuate the loss of cholinergic neuronal immunostaining in the medial septum of mice. These studies demonstrate for the first time that by increasing the brain concentration of NGF, intraventricularly transplanted MSCs might play an important role in the treatment of traumatic brain injury.

Spatial and temporal characteristics of neurodegeneration after controlled cortical impact in mice: more than a focal brain injury

The present study examined the neuropathology of the lateral controlled cortical impact (CCI) traumatic brain injury (TBI) model in mice utilizing the de Olmos silver staining method that selectively identifies degenerating neurons and their processes. The time course of ipsilateral and contralateral neurodegeneration was assessed at 6, 24, 48, 72, and 168 h after a severe (1.0 mm, 3.5 M/sec) injury in young adult CF-1 mice. At 6 hrs, neurodegeneration was apparent in all layers of the ipsilateral cortex at the epicenter of the injury. A low level of degeneration was also detected within the outer molecular layer of the underlying hippocampal dentate gyrus and to the mossy fiber projections in the CA3 pyramidal subregions. A time-dependent increase in cortical and hippocampal neurodegeneration was observed between 6 and 72 hrs post-injury. At 24 h, neurodegeneration was apparent in the CA1 and CA3 pyramidal and dentate gyral granule neurons and in the dorsolateral portions of the thalamus. Image analysis disclosed that the overall volume of ipsilateral silver staining was maximal at 48 h. In the case of the hippocampus, staining was generalized at 48 and 72 h, indicative of damage to all of the major afferent pathways: perforant path, mossy fibers and Schaffer collaterals as well as the efferent CA1 pyramidal axons. The hippocampal neurodegeneration was preceded by a significant increase in the levels of calpain-mediated breakdown products of the cytoskeletal protein alpha-spectrin that began at 6 h, and persisted out to 72 h post-injury. Damage to the corpus callosal fibers was observed as early as 24 h. An anterior to posterior examination of neurodegeneration showed that the cortical damage included the visual cortex. At 168 h (7 days), neurodegeneration in the ipsilateral cortex and hippocampus had largely abated except for ongoing staining in the cortical areas surrounding the contusion lesion and in hippocampal mossy fiber projections. Callosal and thalamic neurodegeneration was also very intense. This more complete neuropathological examination of the CCI model shows that the associated damage is much more widespread than previously appreciated. The extent of ipsilateral and contralateral neurodegeneration provides a more complete anatomical correlate for the cognitive and motor dysfunction seen in this paradigm and suggests that visual disturbances are also likely to be involved in the post-CCI neurological deficits.

Alveolar bone marrow as a cell source for regenerative medicine: differences between alveolar and iliac bone marrow stromal cells

We isolated and expanded BMSCs from human alveolar/jaw bone at a high success rate (70%). These cells had potent osteogenic potential in vitro and in vivo, although their chondrogenic and adipogenic potential was less than that of iliac cells.

INTRODUCTION

Human bone marrow stromal cells (BMSCs) have osteogenic, chondrogenic, and adipogenic potential, but marrow aspiration from iliac crest is an invasive procedure. Alveolar BMSCs may be more useful for regenerative medicine, because the marrow can be aspirated from alveolar bone with minimal pain.

MATERIALS AND METHODS

In this study, alveolar bone marrow samples were obtained from 41 patients, 6-66 years of age, during the course of oral surgery. BMSCs were seeded and maintained in culture with 10% FBS and basic fibroblast growth factor. In addition, BMSCs were induced to differentiate into osteoblasts, chondrocytes, or adipocytes in appropriate medium.

RESULTS AND CONCLUSION

From a small volume (0.1-3 ml) of aspirates, alveolar BMSCs expanded at a success ratio of 29/41 (70%). The success rate decreased with increasing donor age, perhaps because of age-dependent decreases in the number and proliferative capacity of BMSCs. The expanded BMSCs differentiated into osteoblasts under osteogenic conditions in 21-28 days: the mRNA levels of osteocalcin, osteopontin, and bone sialoprotein, along with the calcium level, in alveolar BMSC cultures were similar to those in iliac cultures. However, unlike iliac BMSC, alveolar BMSC showed poor chondrogenic or adipogenic potential, and similar differences were observed between canine alveolar and iliac BMSCs. Subsequently, human alveolar BMSCs attached to beta-tricalcium phosphate were transplanted into immunodeficient mice. In transplants, new bone formed with osteoblasts and osteocytes that expressed human vimentin, human osteocalcin, and human GAPDH. These findings suggest that BMSCs have distinctive features depending on their in vivo location and that alveolar BMSCs will be useful in cell therapy for bone diseases.

Detection of 111In-oxine-labeled bone marrow stromal cells after intravenous or intralesional administration in chronic paraplegic rats

Recent studies suggested that bone marrow stromal cells (BMSC) may have a therapeutic role in the treatment of paraplegia secondary to severe spinal cord injury (SCI). For this reason, we have studied the possibility of using nuclear medicine imaging techniques to evaluate the permanency and migration of BMSC after transplantation procedures in chronic paraplegic Wistar rats. After intravenous administration of 111In-oxine-labeled BMSC, gammagraphic images showed that the activity distributed all over the organism, but in the spinal cord only scarce activity was identified. When 111In-oxine-labeled BMSC were injected within the traumatic centromedullary cavity of paraplegic animals, the gammagraphic images showed persistent activity in the lesion zone, without any activity migrating to the rest of the organism, at least during the whole time of the study (10 days after transplantation procedures). Our results show the utility of 111In labeling for to know the permanency and distribution of BMSC after grafting procedures, and suggest the convenience of the intralesional administration of BMSC, instead of the intravenous administration, in the treatment of chronic traumatic paraplegia.

A Review and Rationale for the Use of Cellular Transplantation as a Therapeutic Strategy for Traumatic Brain Injury

Experimental research during the past decade has greatly increased our understanding of the pathophysiology of traumatic brain injury (TBI) and allowed us to develop neuroprotective pharmacological therapies. Encouraging results of experimental pharmacological interventions, however, have not been translated into successful clinical trials, to date. Traumatic brain injury is now believed to be a progressive degenerative disease characterized by cell loss. The limited capacity for self-repair of the brain suggests that functional recovery following TBI is likely to require cellular transplantation of exogenous cells to replace those lost to trauma. Recent advances in central nervous system transplantation techniques involve technical and experimental refinements and the analysis of the feasibility and efficacy of transplantation of a range of stem cells, progenitor cells and postmitotic cells. Cellular transplantation has begun to be evaluated in several models of experimental TBI, with promising results. The following is a compendium of these new and exciting studies, including a critical discussion of the rationale and caveats associated with cellular transplantation techniques in experimental TBI research. Further refinements in future research are likely to improve results from transplantation-based treatments for TBI.

Infusion of Human Umbilical Cord Blood Cells in a Rat Model of Stroke Dose-Dependently Rescues Behavioral Deficits and Reduces Infarct Volume

BACKGROUND AND PURPOSE

Intravenously delivered human umbilical cord blood cells (HUCBC) have been previously shown to improve functional recovery of stroked rats. To extend these findings, we examined the behavioral recovery and stroke infarct volume in the presence of increasing doses of HUCBC after permanent middle cerebral artery occlusion (MCAO).

METHODS

Rats were subjected to MCAO and allowed to recover for 24 hours before intravenous infusion of 10(4) up to 3 to 5x10(7) HUCBC. Behavioral tests (spontaneous activity, step test, elevated body swing test) were performed 1 week before MCAO and at 2 and 4 weeks after HUCBC infusion. On completion of behavioral testing, animals were euthanized and brain infarct volumes quantified. HUCBC were identified by immunofluorescence for human nuclei and by polymerase chain reaction (PCR) using primers specific for human glycerol 3-phosphate dehydrogenase.

RESULTS

At 4 weeks after infusion, there was a significant recovery in behavioral performance when 10(6) or more HUCBC were delivered (p=0.001 to p=0.05). Infarct volume measurements revealed an inverse relationship between HUCBC dose and damage volume, which reached significance at the higher HUCBC doses (10(7) cells, p<0.01; 3 to 5x10(7) cells, p<0.05). Moreover, HUCBC were localized by immunohistochemistry and PCR analysis only in the injured brain hemisphere and spleen.

CONCLUSIONS

These results extend previous observations of HUCBC infusion in the MCAO rat stroke model by demonstrating a dose relationship between HUCBC, behavioral improvement, and neuronal sparing.

Intravenously injected neural progenitor cells of transgenic rats can migrate to the injured spinal cord and differentiate into neurons, astrocytes and oligodendrocytes

Transplantation of neural progenitor cells (NPCs) has been reported recently to promote regeneration of the injured spinal cord. In the majority of these reports, cell transplantation was performed by local injection with a needle. However, direct injection might be too invasive for clinical use; therefore, the authors investigated a new method of delivering NPCs for the treatment of spinal cord injury. In this study, NPCs were obtained from E15 fetal hippocampus of transgenic rats expressing green fluorescent protein and 100,000 cells were transplanted intravenously into each animal 24h after contusion injury. It was found that the injected NPCs migrated to the lesion site widely and demonstrated nestin at an early phase after transplantation. These NPCs differentiated into neurons, astrocytes and oligodendrocytes, and survived at least for 56 days. These results indicated that intravenously injected neural stem cells migrated into the spinal cord lesion while preserving their potential as NPCs, and that this procedure is a potential method of delivering cells into the lesion for the treatment of spinal cord injury.