Trigeminal complications arising after surgery of cranial base meningiomas.

Chronic severe facial pain is a feared sequel of cranial base surgery. This study explores the symptomatology, incidence and impact on the individual of postoperative de novo trigeminal nerve affection as well as the recovery potential. Out of 231 patients operated for cranial base meningiomas at the Karolinska University Hospital during 7 years, 25 complained of de novo trigeminal symptoms at clinical follow-up 3 months after surgery. Six were later lost to follow-up leaving 19 participants in the study, which was conducted using a questionnaire and a structured telephone interview. All patients complained of facial numbness, affecting the V1 branch in 10/19 patients (53%), the V2 branch in 18/19 (95%) and the V3 branch in 9/19 (47%). Surprisingly, only three (16%) suffered from trigeminal pain, which could be adequately managed by pharmacotherapy. However, five patients (26%) demonstrated ocular dysaesthetic problems. Twelve (63%) described their handicap to be mild, while seven (37%) had daily or severe symptoms. Five patients (26%) reported no improvement over time, while nine (47%) showed improvement and four (21%) stated good recovery. Only one patient (5%) claimed complete symptom remission. In the present study, 11% of the patients presented with a de novo postoperative affection of the trigeminal nerve after removal of a cranial base meningioma; 37% of these reported daily/severe symptoms. Only 26% showed good recovery, observed in patients without tumour infiltration of the nerve or intraoperative nerve damage. In spite of frequent complaints of numbness, pain was uncommon (16%) and often manageable by pharmacotherapy, while ocular symptoms turned out to be more frequent and more disabling than expected.

Endoscopically harvested stem cells: a putative method in future autotransplantation.

OBJECTIVE: The discovery of stem cells in the adult human brain and developing stem cell technology open a possible future scenario of autotransplantation, where stem cells are harvested from the patient and propagated in vitro before they are used as transplants. The objectives of this study were: 1) to investigate the feasibility of harvesting tissue containing neural stem cells by endoscopy; 2) to study the possibility of propagating and multiplying stem cells from this tissue efficiently in vitro; and 3) to examine whether the stem cells differentiate into functional neurons. METHODS: In 13 patients with hydrocephalus undergoing routine neurosurgical procedures, we used an endoscope and a 3-mm biopsy forceps (Medtronic) to harvest the small piece of the ventricular wall that is detached by the introduction of the endoscope. Cells were cultured as neurospheres, and after induced differentiation, they were investigated with immunocytochemistry and whole-cell patch-clamp recordings. All cells characterized were propagated under strict clonal conditions. RESULTS: We found it uncomplicated to harvest the part of the lateral ventricular wall that compares with the inner lumen of the endoscope. Single cells, isolated and cultivated in vitro, multiplied to form neurospheres in a serum-free environment. A single stem cell had the potential to give rise to approximately 9 x 10(5) new cells after two passages. The total number of cells produced from a single biopsy was already, after the second passage, far beyond the number required in, for instance, Parkinson's disease. Within 1 week of induced differentiation, cells expressing markers for neurons (beta-III-tubulin or NeuN), oligodendrocytes (RIP or O4), and astrocytes (glial fibrillary acidic protein) appeared. After 3 weeks, cells with a neuronal phenotype showed a firing pattern distinctive of mature neurons, including repetitive, short-lasting, and overshooting action potentials that were blocked by inhibiting voltage-dependent Na+-channels with tetrodotoxin. CONCLUSION: These results indicate that it may be feasible to produce neural tissue for autotransplantation from endoscopically harvested stem cells, but further work is needed in refining culture protocols to control phenotype fate.

Titanium mesh implantation--a method to stabilize the spine and protect the spinal cord following a multilevel laminectomy in the adult rat.

The development of clinically relevant larger spinal cord injury models is in part limited by the possibility of a widened or multilevel laminectomy causing a spinal cord injury from an unstable spine or from compression of the spinal cord by adjacent soft tissues. In the adult rat, we have developed a method to protect the spinal cord and stabilize the spinal column using a titanium mesh implant following a bilateral, multilevel lumbar laminectomy. For this purpose, bilateral and expanded L1-4 laminectomies were performed with or without the use of a titanium mesh to protect the spinal cord and stabilize the spine. Without titanium mesh protection, the rats developed a severe paraparesis or paraplegia, urinary retention, gross anatomical signs of cord compression, and motoneuron loss. In the titanium mesh treatment group, the rats typically maintained a normal gait and lower urinary tract function, normal gross anatomical features of the spinal cord, and normal motoneuron counts. We propose that the use of a titanium mesh implant may assist in the development of clinically relevant larger spinal cord injury and repair models.

Multipotent progenitor cells from the adult human brain: neurophysiological differentiation to mature neurons.

It was long held as an axiom that new neurons are not produced in the adult human brain. More recent studies have identified multipotent cells whose progeny express glial or neuronal markers. This discovery may lead to new therapeutic strategies for CNS disorders, either by stimulating neurogenesis in vivo or by transplanting multipotent progenitor cells (MPCs) that have been propagated and differentiated in vitro. The clinical application of such approaches will be limited by the ability of these cells to develop into functional neurons. To facilitate an understanding of mechanisms regulating neurogenesis in the adult human brain, we characterized the developmental processes MPCs go through when progressing to a neuron. Human tissue was harvested during temporal lobe resections because of epilepsy, and cells were cultured as neurospheres. Our findings demonstrate that at an early stage, these cells often stain with neuronal markers without possessing any functional neuronal properties. Over a period of 4 weeks in culture, cells go through characteristic steps of morphological and electrophysiological development towards functional neurons; they develop a polarized appearance with multiple dendrites, whereas the membrane potential becomes more negative and the input resistance decreases [from -48 +/- 10 mV/557 +/- 85 MOmega (n = 15) between days 7 and 11 to -59 +/- 9 mV/380 +/- 79 MOmega (n = 9) between days 25 and 38, respectively]. Active membrane properties were first observed on day 7 and consisted of a voltage-gated K+-current. Later in the second week the cells developed voltage-gated Ca2+-channels and fired small Ca2+-driven action potentials. Immature Na+-driven action potentials developed from the beginning of the third week, and by the end of the fourth week the cells fired repetitive action potentials with a completely mature waveform generated by the combined action of the voltage-gated ionic channels INa, IA and IK. After 4 weeks, the newly formed neurons also communicated by the use of GABAergic and glutamatergic synapses. The adult human brain thus harbours MPCs, which have the ability to develop into neurons and in doing this follow characteristic steps of neurogenesis as seen in the developing brain.

Development of neuronal networks from single stem cells harvested from the adult human brain.

OBJECTIVE: It was long held as an axiom that new neurons are not produced in the adult human brain. More recent studies, however, have identified multipotent cells whose progeny express glial or neuronal markers. This discovery may lead to new therapeutic strategies against central nervous system disorders by transplanting stem cells that have been propagated in vitro. Still, it is not known whether stem cells from the adult human brain retain the potential to mature into neurons that integrate and communicate in a network. METHODS: We cultured cells from the ventricular wall of the adult human brain as monoclonal neurospheres. After two passages, the neurospheres were dissociated and the cells were allowed to differentiate. After 4 weeks of maturation, the cells were studied by immunocytochemistry, confocal microscopy, and whole-cell patch-clamp. RESULTS: We show that monoclonal stem cells harvested from the ventricular wall of the adult human brain develop into mature neurons with functional glutamate receptors and glutamatergic nerve terminals. By patching pairs of cells simultaneously, we also present direct evidence for synaptic communication between neurons developed from the same monoclonal cell. CONCLUSION: Neural stem cells harvested from the adult human brain retain the potential to mature into fully differentiated neurons that integrate and communicate by synapses. This opens a possible future scenario of autotransplantation, in which stem cells are harvested from small biopsies of the ventricular wall and propagated in vitro before transplantation.

Differential distribution of growth associated protein (GAP-43) in the motor nuclei of the adult rat conus medullaris.

GAP-43 is normally produced by neurons during developmental growth and axonal regeneration, but it is also expressed in specific regions of the normal adult nervous system. We studied the protein expression of GAP-43 within the conus medullaris portion of the spinal cord in adult male rats. Immunohistochemistry for choline acetyltransferase (ChAT) was first performed to identify specific efferent autonomic and motor nuclei in lumbosacral segments of the spinal cord. Adjacent sections were then processed for GAP-43 immunoreactivity (IR). We show GAP-43 IR in the superficial portion of the dorsal horn, the intermediolateral nucleus, and the dorsal commissural tract. We also demonstrate a differential distribution of GAP-43 IR between different motor nuclei of the conus medullaris. Using densitometry, the most prominent GAP-43 IR was detected in the dorsolateral and dorsomedial motor nuclei, which represent the human Onuf's nucleus homologue. Confocal microscopy of double immunofluorescent labeling for ChAT and GAP-43 demonstrate GAP-43 IR in the neuropil of the autonomic and motor nuclei, and many of the GAP-43 IR arbors are in close apposition with the efferent cholinergic neurons. We note that the efferent neurons of both the autonomic and somatic nuclei, which are ultimately responsible for the integrated normal control of the lower urinary tract, bowel and sexual functions, are heavily innervated by GAP-43 enriched projections. We speculate that these functionally related neurons retain a physiological GAP-43-associated synaptic plasticity throughout adult life.

Methylprednisolone treatment does not influence axonal regeneration or degeneration following optic nerve injury in the adult rat.

BACKGROUND: Methylprednisolone (MP) is often used to treat optic nerve injury. However, its effects in experimental crush injury have not been extensively evaluated. METHODS: Adult Sprague-Dawley rats were subjected to a standardized optic nerve crush injury. Animals were treated either with 30 mg/kg MP intravenous bolus followed by subcutaneous injections every 6 hours for 48 hours, or with a drug vehicle alone. RESULTS: The injury resulted in a partial loss of neuronal nuclei-labeled retinal neurons and a corresponding degeneration of axons distal to the injury. EDI-labeled macrophages accumulated at the site of lesion, phagocyting FJ-labeled axonal debris. Regenerative fibers expressing growth associated protein-43 were seen proximal to the lesion, but did not traverse the glial scar. Analysis of optic nerve function using visual evoked potentials showed typical signals in intact animals, which were abolished after injury in MP-treated and untreated animals. CONCLUSIONS: We did not detect any effects of MP on retinal cell survival, macrophage activity at the site of injury, axonal degeneration/regeneration, or visual function. These experimental results provide a physiologic underpinning for the lack of efficacy demonstrated in a large trial of MP treatment of clinical optic nerve injury.

Stem cells from the adult human brain develop into functional neurons in culture.

Recent research communications indicate that the adult human brain contains undifferentiated, multipotent precursors or neural stem cells. It is not known, however, whether these cells can develop into fully functional neurons. We cultured cells from the adult human ventricular wall as neurospheres and passed them at the individual cell level to secondary neurospheres. Following dissociation and plating, the cells developed the antigen profile of the three main cell types in the brain (GFAP, astrocytes; O2, oligodendrocytes; and beta-III-tubulin/NeuN, neurons). More importantly, the cells developed the electrophysiological profiles of neurons and glia. Over a period of 3 weeks, neuron-like cells went through the same phases as neurons do during development in vivo, including up-regulation of inward Na+ -currents, drop in input resistance, shortening of the action potential, and hyperpolarization of the cell membrane. The cells developed overshooting action potentials with a mature configuration. Recordings in voltage-clamp mode displayed both the fast inactivating TTX-sensitive sodium current (INa) underlying the rising phase of the action potential and the two potassium currents terminating the action potential in mature neurons (IA and IK, sensitive to 4-AP and TEA, respectively). We have thus demonstrated that the human ventricular wall contains multipotent cells that can differentiate into functionally mature neurons.

Artificial niches for human adult neural stem cells: possibility for autologous transplantation therapy.

Cellular transplantation therapy is thought to play a central role in the concept of restorative neurosurgery, which aims to restore function to the damaged nervous system. Stem cells represent a potentially renewable source of transplantable cells. However, control of the behavior of these cells, both in the process of clonogenic expansion and post-transplantation, represents formidable challenges. Stem cell behavior is thought to be directed by extracellular signals in their in vivo niches, many of which are protein or peptide based. As only one example, activation of Notch plays an important role in normal development and is the strongest known signal for stem cells to choose glial over neuronal fates. Therefore, artificial extracellular matrix proteins represent a potentially powerful tool to custom design artificial niches to strategically control stem cell behavior. We have developed a family of aECM proteins that incorporate the active domains of the DSL ligands to the Notch receptor into an elastin-based backbone. The development of our DSL-elastin artificial proteins demonstrates the design strategy and methodology for the production of bioactive artificial extracellular matrix proteins aimed at modulating stem cell behavior, and this method can be used to design other bioactive aECM proteins. In addition, we have developed a method for the isolation and characterization of adult human neural stem cells from periventricular tissue harvested from living patients. This paper reviews cellular transplantation therapy from the clinical perspective and summarizes ongoing work aimed at exploring the intriguing possibility of autologous transplantation, whereby neural stem cells can be harvested from adult patients, expanded or modified in vitro in artificial niches, and retransplanted into the original patient.