Superior cervical ganglion regenerating axons through peripheral nerve grafts and reversal of behavioral deficits in hemiparkinsonian rats

De novo malignant optic chiasm glioma with initial clinical response to steroids

Malignant optic nerve glioma (MONG) is a rare but uniformly fatal disease that remains poorly understood. We describe a notable case of this rare disease occurring in the optic chiasm. Normal brain imaging and normal ophthalmic examination two years prior to diagnosis provide evidence for de novo genesis of MONG in our patient. Early response to steroids highlights the degree to which MONG can initially mimic inflammatory optic neuropathies and chiasmal syndromes. Our case also demonstrates a poor outcome with MONG even with current advanced therapy for glioblastoma including radiotherapy plus concomitant and adjuvant temozolomide (the EORTC/NCIC regimen) and bevacizumab.

Rare suprasellar glioblastoma: report of two cases and review of the literature

BACKGROUND AND IMPORTANCE

The suprasellar and hypothalamic/chiasmatic regions can harbor a broad range of pathologic conditions, both neoplastic and nonneoplastic; however, malignant gliomas are extremely rare in those regions.

CLINICAL PRESENTATIONS

Patient 1 was a 70 year-old man with weight loss and rapidly progressive visual impairment. A mass centered in the hypothalamus was detected on magnetic resonance (MR) imaging. The second patient, a 45 year-old woman, complained of visual symptoms and headaches. MR imaging revealed a combined intra- and suprasellar mass. In both instances, the preoperative differential diagnosis favored craniopharyngioma. Histological examination confirmed the diagnosis of glioblastoma.

CONCLUSION

We report two rare adult cases of hypothalamic/chiasmatic glioblastoma. The authors review the literature, highlighting the importance of considering this rare entity in the differential diagnosis of suprasellar and hypothalamic lesions.

Tracking extranigral degeneration in animal models of Parkinson's disease: quest for effective therapeutic strategies

Sporadic Parkinson's disease (PD) is now interpreted as a complex nervous system disorder in which the projection neurons are predominantly damaged. Such an interpretation is based on mapping of Lewy body and Lewy neurite pathology. Symptoms of the human disease are much widespread, which span from pre-clinical non-motor symptoms and clinical motor symptoms to cognitive discrepancies often seen in advanced stages. Existing symptomatic treatments further complicate with overt drug-irresponsive symptoms. PD is better understood by assimilation of extranigral degenerative pathways with nigrostriatal degenerative mechanisms. The term 'extranigral' appeared first in the 1990s to more rigorously define the nigral pathology by process of elimination. However, as clinicians progressively identified PD symptoms unresponsive to the gold standard drug l-DOPA, definitions of PD symptoms were redefined. Non-motor symptoms prodromal to motor symptoms just as pre-clinical to clinical, and conjointly emerged the concept of nigral versus extranigral degeneration in PD. While nigrostriatal degeneration is responsible for the neurobiological substrates of extrapyramydal motor features, extranigral degeneration corroborates a vast majority of other changes in discrete central, peripheral, and enteric nervous system nuclei, which together account for global symptoms of the human disease. As an extranigral site, spinal cord degeneration has also been implicated in PD progression. Interconnected to the upper CNS structures with descending and ascending pathways, spinal neurons participate in movement and sensory circuits, controlling movement and reflexes. Several clinical and in vivo studies have demonstrated signs of parkinsonism-related degenerative processes in spinal cord, which led to recent consideration of spinal cord as an area of potential therapeutic target. In a nutshell, this review explores how the existing animal models can actually reflect the human disease in order to facilitate PD research. Evolution of extranigral degeneration studies has been succinctly revisited, followed by a survey on animal models in light of recent findings in clinical PD. Together, it may help to develop effective therapeutic strategies for PD.

Malignant transformation of an optic pathway glioma without prior radiation therapy

Optic pathway gliomas (OPGs) arise from the optic nerves, optic chiasm, and/or hypothalamus and most commonly occur in childhood. Although these tumors can be quite challenging to manage, they are typically low-grade astrocytomas histologically, most commonly pilocytic astrocytomas. The few previously reported cases of malignant degeneration of an OPG occurred after external beam radiation therapy. The authors report the first case in the English literature of an OPG that transformed from a low-grade astrocytoma, with features most consistent with a pilocytic astrocytoma, to a malignant glioma without any exposure to radiation therapy.

Cells of the sympathoadrenal lineage: Biological properties as donor tissue for cell-replacement therapies for Parkinson's disease

Sympathoadrenal (SA) cell lineage encompasses neural crest derivatives such as sympathetic neurons, small intensely fluorescent (SIF) cells of sympathetic ganglia and adrenal medulla, and chromaffin cells of adrenal medulla and extra-adrenal paraganglia. SA autografts have been used for transplantation in Parkinson's disease (PD) for three reasons: (i) as autologous donor tissue avoids graft rejection and the need for immunosuppressant therapy, (ii) SA cells express dopaminotrophic factors such as GNDF and TGFbetas, and (iii) although most of SA cells release noradrenaline, some of them are able to produce and release dopamine. Adrenal chromaffin cells were the first SA transplanted cells in both animal models of PD and PD patients. However, these autografts have met limited success because long-term cell survival is very poor, and this approach is no longer pursued clinically. Sympathetic neurons from the superior cervical ganglion have been also grafted in PD animal models and PD patients. Poor survival into brain parenchyma of grafted tissue is a serious disadvantage for its clinical application. However, cultured sympathetic cell grafts present a better survival rate, and they reduce the need for levodopa medication in PD patients by facilitating the conversion of exogenous levodopa. SA extra-adrenal chromaffin cells are located on paraganglia (i.e., the Zuckerkandl's organ), and have been used for grafting in a rodent model of PD. Preliminary results indicate that long-term survival of these cells is better than for other SA cells, exerting a more prolonged restorative neurotrophic action on denervated host striatum. The ability of SA extra-adrenal cells to respond to hypoxia, differently to SA sympathetic neurons or adrenal medulla cells, could explain their good survival rate after brain transplantation.

Unilateral adult malignant optic nerve glioma

INTRODUCTION

Adult malignant optic nerve gliomas are rare and rapidly fatal visual pathway tumours. They represent a clinical entity different from the more common childhood benign optic nerve gliomas, which are frequently associated with neurofibromatosis I.

CASE REPORT

A 61-year-old woman presented with rapidly progressing right vision loss, lower altitudinal visual field defect and papilloedema. MRI showed intraorbital and intracranial swelling of the right optic nerve. Resection of the intracranial part of the right optic nerve up to the chiasm revealed anaplastic astrocytoma grade III. Within 1 year, the patient died of leptomeningeal metastasis despite radiotherapy. Clinical and MRI evaluation of the left eye and optic nerve were normal at all times.

DISCUSSION

Unilateral adult malignant glioma of the optic nerve is exceptional. The final diagnosis was only confirmed by optic nerve biopsy. In the literature, only one patient has been reported with a unilateral tumour manifestation; he was lost to follow-up 3 months later. All other cases were bilateral. To date, 44 case reports of adult malignant optic nerve glioma have been published, either malignant astrocytoma or glioblastoma. These tumours can mimic optic neuritis in their initial presentation. The diagnosis is seldom made before craniotomy. On MRI images, malignant glioma cannot be distinguished from optic nerve enlargement due to other causes. Although radiotherapy appears to prolong life expectancy, all presently available treatment options (radiation, surgery, radio-chemotherapy) are of limited value. Most patients go blind and die within 1 or 2 years.

Xenografting human T2 sympathetic ganglion from hyperhidrotic patients provides short-term restoration of catecholaminergic functions in hemiparkinsonian athymic rats

Previous studies have suggested that allografting peripheral sympathetic ganglia, such as superior cervical ganglia, partially relieves clinical or behavioral deficits in parkinsonian patients and animals. However, removal of these ganglia can cause Homer's syndrome, which limits the utilization of this approach. Hyperhidrosis, a disease of excessive sweating, is commonly seen in young Orientals. Treatment of hyperhidrosis often involves surgical removal of the second thoracic sympathetic ganglia (T2G), which contain catecholaminergic neurons. The purpose of our study was to investigate behavioral responses and tyrosine hydroxylase (TH) immunoreactivity in hemiparkinsonian rats at different time points after transplantation of human T2G from hyperhidrotic patients. Athymic Fisher 344 rats were injected unilaterally with 6-hydroxydopamine into the medial forebrain bundle to destroy the nigrostriatal dopaminergic (DA) pathway. The effectiveness of lesions was tested by measuring methamphetamine (MA)-induced rotations. These unilaterally lesioned rats were later transplanted with T2G or T2 fiber tract (T2F) obtained from adult hyperhidrotic patients. Animals grafted with T2G showed a reduction in MA-induced rotation by 2 weeks; however, rotation returned to the pregrafting levels by 3 months. Animals receiving T2F grafts did not show any reduction of rotation over a 3-month period. Animals were later sacrificed for TH immunostaining at different time points. Tyrosine hydroxylase-positive [TH(+)] cell bodies and fibers were found in the lesioned striatum 2-4 weeks after T2G grafting, suggesting the survival of transplants. Two to 3 months after grafting, TH(+) fibers were still found in almost all the recipients. However, TH(+) cell bodies were found in only three of seven rats studied. Animals receiving T2F grafting did not show any TH immunoreactivity in the lesioned striatum over the 3-month period. These data indicate that T2G transplants from adult hyperhidrotic patients can survive and provide transient normalization of the motor behavior in the hemiparkinsonian athymic rats. Because of the short-term improvement in behavior after grafting, the use of T2G in human trials should be cautious at the present time. Further laboratory research is required.