Fetal Spinal Cord Grafts Research Articles

Characteristics of human fetal spinal cord grafts in the adult rat spinal cord: influences of lesion and grafting conditions.

The present study evaluated the growth potential and differentiation of human fetal spinal cord (FSC) tissue in the injured adult rat spinal cord under different lesion and grafting conditions. Donor tissue at 6-9 weeks of gestational age was obtained through elective abortions and transplanted either immediately into acute resection (solid grafts) or into chronic contusion (suspension and solid grafts) lesions (i.e., 14-40 days after injury) in the thoracic spinal cord. The xenografts were then examined either histologically in plastic sections or immunocytochemically 1-3 months postgrafting. Intraspinal grafts in acute lesions demonstrated an 83% survival rate and developed as well-circumscribed nodules that were predominantly composed of immature astrocytes. Solid-piece grafts in chronic contusion lesions exhibited a 92% survival rate and also developed as nodular masses. These grafts, however, contained many immature neurons 2 months postgrafting. Suspension grafts in chronic contusion lesions had an 85% survival rate and expanded in a nonrestrictive, diffuse pattern. These transplants demonstrated large neuronally rich areas of neural parenchyma. Extensive neuritic outgrowth could also be seen extending from these grafts into the surrounding host spinal cord. These findings show that human FSC tissue reliably survives and differentiates in both acute and chronic lesions. However, both the lesion environment and the grafting techniques can greatly influence the pattern of differentiation and degree of host-graft integration achieved.

Minor immunoreactivity in GDNF-, BDNF-, or NT-3-treated substantia nigra allografts.

Glial-cell-line-derived neurotrophic factor (GDNF) stimulates the survival of dopaminergic neurons. Little is known, however, about the possible immune sequelae of GDNF exposure or of exposure to other putative trophic factors. To address these questions, pieces of mesencephalic tissue, substantia nigra, from 15-day-old donor embryos were transplanted into the anterior chamber of the eye of adult male Sprague- Dawley recipient rats. At 5-day intervals, an aliquot (0.5 μg) of GDNF, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), or cytochrome-C (CC) was injected into the anterior chamber of the eye of the recipients, and the sizes of the transplants were measured. GDNF increased transplant survival and growth. On day 42, all rats were sacrificed, and the grafts were evaluated by cresyl-violet staining and by immunohistochemistry using antibodies raised against neurofilament (NF), tyrosine hydroxylase, or glial fibrillary acidic protein (GFAP), as well as the following monoclonai antibodies: OX-38 anti-CD4, OX-8 anti-CD8, OX-18 anti-MHC class I, OX-6 anti- MHC class II, OX-42 anti-CD11b, R-73 anti-α and anti-β T-cell receptor, and EDI raised against monocytes/macrophages. BDNF-treated grafts showed only weak immunoreactivity, and even weaker reactions were seen in grafts treated with NT-3, GDNF, or CC. No single immune system marker was significantly elevated in grafts from any treatment group. We used OX-42 and EDI to study possible alterations of microglial components. Ramified microglial cells were found in GDNF-treated grafts and to a lesser extent in NT-3 and BDNF-treated grafts. EDl-labeled reactive microglial components were found in NT-3- and BDNF-treated grafts. Additionally, large and rounded OX-42-positive phagocytic cells were found in NT-3-treated grafts. Together with our previous finding that GDNF treatment of spinal cord transplants activates immune responses and leads to microglial activation, our data dempnstrate that although treatment with GDNF and to some degree with BDNF can enhance immune responses to immunogenic grafts, such as fetal spinal cord grafts, but the trophic factors per se do not elicit any marked response in non-immunogenic grafts like substantia nigra.

Comparison of the Growth and Fate of Fetal Spinal Iso- and Allografts in the Adult Rat Injured Spinal Cord

Most studies investigating early fetal CNS graft–host interactions and host immune responses have been performed using intracerebral transplantation paradigms. The purpose of this study was to establish the early developmental dynamics of fetal graft integration with the injured host spinal cord and to determine whether fetal allografts in this environment are subject to rejection. ACI rat fetal spinal cord (FSC) tissue was grafted into acute lesion cavities of adult WF rat spinal cords. Graft development and/or rejection was followed from 1 to 45 days posttransplantation with morphometric, histological, and immunocytochemical methods. We determined that all FSC grafts in acute resection lesions of the adult rat spinal cord undergo an early substantial cellular attrition, but following favorable attachment to healthy host tissue margins, they rebound and grow to fill the lesion cavity by approximately 45 days. We also determined that FSC allografts into nonimmunosuppressed adult recipients are consistently rejected, but only after an early period of growth and maturation. The onset of rejection is characterized by extensive cellular infiltration coincidental with graft and host MHC antigen expression. The implications of delayed graft development and graft–host integration are discussed relative to interconnectivity and long-term potential for graft-derived benefits. The observed rejection response was characteristic of first-order allograft rejection and underscores a lack of immunological privilege in the microenvironment of the injured spinal cord.

Fetal neural grafts and repair of the injured spinal cord.

Solid or suspension grafts of fetal spinal cord (FSC), caudal brainstem (FBSt), neocortex (FNCx) or a combination of either FSC/FNCx or FSC/FBSt were placed into cavities produced by static loading (i.e., compression) of the spinal cord of adult cats two to 30 weeks after injury. Extensively vascularized, viable graft tissue was found in all animals with the exception of two cats which showed active rejection of their transplants. Surviving grafts showed many immature characteristics 6-9 weeks after transplantation. However, by 20-30 weeks, FSC and FBSt grafts were more mature. Grafts integrated with the host gray and white matter and neuritic processes from both host and graft were seen crossing the host-graft interface. Host calcitonin gene related peptide (CGRP)-like immunoreactive axons could be traced into FSC and FBSt grafts. A more restricted ingrowth of host serotonin (5-HT)-like immunoreactive fibers was seen in FSC grafts. Our results suggest that the capacity of homotypic transplants to promote recovery of function is greater than heterotypic transplants. Additionally, it appears that the functional capacity of the graft depends upon graft survival, the time interval between injury and transplantation, and whether or not the lesion cavity was debrided prior to grafting.

Migrated fetal astrocytes modulate nerve growth factor expression in host nucleus gracilis of the medulla after grafting in third cervical hindlimb dorsal columns of the spinal cord.

Nerve growth factor (NGF) immunoreactivity in the nucleus gracilis of the medulla was quantitated for 90 days after aspiration of the C3 spinal hindlimb dorsal columns of 36 adult rats. Half the lesioned animals were a lesion-only group. The remaining lesioned animals received an immediate graft of two 1.0-mm pieces of 14 day gestation fetal rat cervical spinal cord (prelabeled with Phaseolus vulgaris leucoagglutinin) into the aspiration pocket (graft group). There were 3 normal controls. Groups of animals were analyzed at 7, 14, 21, 30, 60, and 90 days. At 90 days, NGF immunoreactivity was significantly elevated in the nucleus gracilis of lesion-only animals. This increase in NGF immunoreactivity was augmented in glial end-feet surrounding neurons and was also observed in the cytoplasm of astrocytes and some neurons. Previous experiments have shown that the cluster neurons of the nucleus gracilis undergo atrophy at this time with a concomitant decrease in hindlimb placement. NGF immunoreactivity (90 days) in grafted animals, however, was significantly less than in lesion-only animals (P < 0.05) but remained significantly elevated above control animals (P < 0.05). Unlike in lesion-only animals, there were no NGF positive neurons in the nucleus gracilis of grafted animals. Previous experiments have shown that astrocytes from fetal spinal cord grafts migrate to the nucleus gracilis, maintain cluster neuron cell size, and improve hindlimb placement at 90 days. The present data indicate that modulation of detrimental increases in NGF appeared to be a mechanism by which migrated fetal astrocytes can be used as a system for cell therapy.

Chemical and cellular mediators in spinal cord injury.

Journal of NeurotraumaVol. 9, No. 2 Chemical and Cellular Mediators in Spinal Cord InjuryDOUGLAS K. ANDERSONDOUGLAS K. ANDERSONSearch for more papers by this authorPublished Online:26 Mar 2009https://doi.org/10.1089/neu.1992.9.143AboutSectionsPDF/EPUB ToolsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail FiguresReferencesRelatedDetailsCited ByPredictors of intramedullary lesion expansion rate on MR images of patients with subaxial spinal cord injuryJournal of Neurosurgery: Spine, Vol. 22, No. 6Quercetin attenuates inflammatory processes after spinal cord injury in an animal model4 May 2010 | Spinal Cord, Vol. 48, No. 12Trauma3 January 2013Surgical Approaches for the Operative Management of Cervical Spine FracturesInvestigation of the dose-dependent neuroprotective effects of agmatine in experimental spinal cord injury: a prospective randomized and placebo–control trialJournal of Neurosurgery: Spine, Vol. 4, No. 5Spine Cord Injury: An UpdateSeminars in Spine Surgery, Vol. 17, No. 2Does early decompression improve neurological outcome of spinal cord injured patients? Appraisal of the literature using a meta-analytical approach6 July 2004 | Spinal Cord, Vol. 42, No. 9Management of Missile Head WoundsNeurosurgery Quarterly, Vol. 13, No. 2Non-surgical management of spinal cord injury24 February 2005 | Expert Opinion on Investigational Drugs, Vol. 11, No. 4Current developments in spinal cord injury researchThe Spine Journal, Vol. 2, No. 2Coadministration of Methylprednisolone with Hypertonic Saline Solution Improves Overall Neurological Function and Survival Rates in a Chronic Model of Spinal Cord InjuryNeurosurgery, Vol. 49, No. 6Tonicity of Resuscitative Fluids Influences Outcome after Spinal Cord InjuryNeurosurgery, Vol. 48, No. 1Chemokine antagonist infusion attenuates cellular infiltration following spinal cord contusion injury in ratJournal of Neuroscience Research, Vol. 59, No. 1Chemokine antagonist infusion attenuates cellular infiltration following spinal cord contusion injury in ratJournal of Neuroscience Research, Vol. 59, No. 1Characteristics of Human Fetal Spinal Cord Grafts in the Adult Rat Spinal Cord: Influences of Lesion and Grafting ConditionsExperimental Neurology, Vol. 148, No. 2The effects of taxol, methylprednisolone, and 4-aminopyridine in compressive spinal cord injury: A qualitative experimental studySurgical Neurology, Vol. 46, No. 4Traumatismos medulares experimentales: Revisión de la literatura y descripción de un modelo mediante compresión mantenida en la rataNeurocirugía, Vol. 7, No. 3Effect of a spinal cord photolesion injury on catalase16 December 1999 | International Journal of Developmental Neuroscience, Vol. 13, No. 6Treatment of Acute Injury of the Cervical SpineThe Journal of Bone & Joint Surgery, Vol. 76, No. 12Methylprednisolone and membrane properties of primary cultures of mouse spinal cordBrain Research, Vol. 637, No. 1-2An Experimental Model Combining Microdialysis with Electrophysiology, Histology, and Neurochemistry for Exploring Mechanisms of Secondary Damage in Spinal Cord Injury: Effects of Potassium DANXIA LIU and DAVID J. McADOO26 March 2009 | Journal of Neurotrauma, Vol. 10, No. 3 Volume 9Issue 2Jan 1992 To cite this article:DOUGLAS K. ANDERSON.Chemical and Cellular Mediators in Spinal Cord Injury.Journal of Neurotrauma.Jan 1992.143-146.http://doi.org/10.1089/neu.1992.9.143Published in Volume: 9 Issue 2: March 26, 2009PDF download

Grafted fetal astrocyte migration can prevent host neuronal atrophy: comparison of astrocytes from cultures and whole piece donors

In a 'double blind' study, 2 series of adult rats were trained to traverse a narrow bar or a horizontal ladder for a water reward. Hindlimb placement (measured as hindlimb foot slips) of the subjects trained on the narrow platform was ranked. The subjects traversing the ladder were videotaped and the number of hindlimb slips counted. After reaching criterion (10 complete traverses on each of 2 consecutive days), all animals had the fasciculus gracilis (FG) of the third cervical spinal cord segment (C3) aspirated to sever hindlimb dorsal column afferents. After aspiration of C3FG the subjects were randomly placed in an aspiration-only (controls) or aspiration + graft group. All grafts were prelabeled with the plant lectin Phaseolus vulgaris leucoagglutinin (PHAL) as a graft-derived cell marker. The grafts were either unoriented whole pieces of E14 fetal spinal cord or 105 purified, cultured, E14 fetal spinal cord astrocytes. Subjects were tested at intervals over 90 days. Aspiration of C3FG and a graft of whole pieces of E14 fetal spinal cord resulted in a statistically significant improvement in hindlimb placement at 21 and 90 days (P < 0.05) when compared to controls. In contrast, animals with cultured, purified, E14 fetal spinal cord astrocyte grafts had significantly worse (P < 0.05) hindlimb placement than controls. Immunohistochemical double staining for PHAL and glial fibrillary acidic protein in the same cell showed that astrocytes from both types of grafts migrated to the nucleus gracilis (NG) of the medulla of the host. The grafted fetal astrocytes from the whole piece grafts prevented denervation atrophy of the host NG neurons, whereas cultured grafted fetal astrocytes did not demonstrate this effect. After grafting donor tissue that contained astrocytes into the injured spinal cord there were two accompanying classes of astrocytes. One class derived from whole piece, E14, fetal spinal cord grafts migrated to the NG of the host, prevented atrophy of host NG cluster and interneurons, and improved hindlimb placement. The other class, derived from cultures of E14 fetal spinal cord astrocytes, migrated to the NG of the host, failed to maintain the size of cluster neurons and interneurons of the host NG, and resulted in a greater hindlimb placement deficit when compared to controls. These data suggest that improvement of hindlimb placement due to graft-derived fetal astrocytes in injured host spinal cord was due to the ability of the astrocytes to maintain host neurons and neuronal networks.

Differentiation of substantia gelatinosa-like regions in intraspinal and intracerebral transplants of embryonic spinal cord tissue in the rat

The differentiation of intracerebral and intraspinal transplants of fetal (E 14–E 15) rat spinal cord was studied to determine the extent to which myelin-free zones in these embryonic grafts exhibit cytological features and immunocytochemical characteristics of the substantia gelatinosa (SG) of the normal spinal cord. Immunocytochemical staining with antiserum to myelin basic protein (MBP) revealed myelin-free areas of varying proportions within fetal spinal cord grafts. These regions were identified in both newborn and adult recipients regardless of whether donor tissue was grafted to heterotopic (intracerebral) or homotopic (intraspinal) sites. As in the SG of the intact spinal cord, the myelin-free regions consisted mainly of small (7–15 μm) diameter neurons. At the ultrastructural level, these cells were surrounded by a neuropil composed of numerous small caliber, unmyelinated axons and intermediate-sized dendrites. Synaptic terminals in these areas were primarily characterized by the presence of clear, round vesicles, although granular vesicles were occasionally found within these terminals. Immunocytochemical staining demonstrated met- and leu-enkephalin-, neurotensin-, substance P-, and somatostatin-like immunoreactive elements within these myelin-free areas. Thus, regions within embryonic spinal cord grafts undergo some topographical differentiation which parallels that of the normal superficial dorsal horn. The presence of SG-like regions illustrates the potential capacity of fetal spinal cord transplants for replacing some intraspinal neuronal populations at the site of a spinal cord injury in neonatal and adult animals. These graft regions may serve as a source of intersegmental projection neurons or establish an extensive intrinsic circuitry similar to that seen in the normal SG. In addition, the definition of these areas provides a useful model to study the innervation patterns of host axons that typically project to the substantia gelatinosa of the normal spinal cord.

Fetal spinal cord homografts ameliorate the severity of lesion-induced hind limb behavioral deficits

Fetal spinal cord grafts survive for long periods in host spinal cord. We explored the ability of such grafts into a lesion in C3 fasciculus gracilis to influence the expected deterioration of hind limb performance following this lesion. Ten adult Sprague-Dawley rats were placed on a schedule of 23 h off and 1 h on water. These subjects were then trained to traverse a narrow platform for a water reward. Criterion was established as 10 trials/day completed in 15 s a trial for 2 consecutive days. Animals were ranked for hind limb and forelimb performance utilizing slips, recovery, and manner of traversing the platform. In a triple-blind experimental design, the animals' identification was coded and laminectomy performed at C3. The fasciculus gracilis was bilaterally transected at the rostral and caudal borders of the segment and aspirated. Five subjects were chosen at random immediately after the lesion was made for the implantation of two 1-mm segments of E14 spinal cord from fetuses of timed pregnant Sprague-Dawley dams at the time of the lesion. Coded lesion and lesion-transplant animals were then tested after 21, 30, 45, 60, and 90 days until criterion or for 4 days. Hind limb performance of the lesion-only (ANOVA χ 2 = 13.04, df 5; P < 0.05) and lesion-transplant groups (ANOVA χ 2 = 11.82, df 5; P < 0.05) showed that the C3 fetal transplants significantly decreased ( P < 0.05) the severity of hind limb deficit at 21 days postlesion and significantly ( P < 0.05) decreased the expected foot slips and limb recovery to the platform that was expected and did develop in lesion-only animals at 90 days. There were no significant differences in forelimb performance (ANOVAs P > 0.05). There were few small-caliber nerve fibers in the fasciculus gracilis at the level of C1 indicating that reinnervation was not a major factor in the reduction of the deficit.

Transplantation of cultured fetal spinal cord grafts, grown on a histocompatible substrate, into adult spinal cord

Cell suspensions from 14-day gestation rat spinal cord can be successfully cultured on collagen gels containing laminin. After 7 and 14 days in culture the gels were removed from the dish and slices of gel with cultured cells were transplanted into the dorsal column of adult rats. Thirty days later there was no evidence of the gel. However, grafted neurons with well-developed organelles, axons, dendrites, axosomatic and axodendritic synapses were observed in the white matter of the host dorsal columns. Oligodendrocytes and astrocytes were also observed in the graft. This histocompatible substrate for culturing fetal CNS is a mechanism for transplanting cultured CNS cells as grafts of known maturity and synaptic organization into adult host CNS.