Marcello Passalacqua

Beneficial effects of systemic administration of recombinant human erythropoietin in rabbits subjected to subarachnoid hemorrhage.

Cerebral vasospasm and ischemic damage are important causes of mortality and morbidity in patients affected by aneurysmal subarachnoid hemorrhage (SAH). Recently, i.p. administration of recombinant human erythropoietin (r-Hu-EPO) has been shown to exert a neuroprotective effect during experimental SAH. The present study was conducted to evaluate further the effect of r-Hu-EPO administration after SAH in rabbits on neurological outcome, degree of basilar artery spasm, and magnitude of neuronal ischemic damage. Experimental animals were divided into six groups: group 1 (n = 8), control; group 2 (n = 8), control plus placebo; group 3 (n = 8), control plus r-Hu-EPO; group 4 (n = 8), SAH; group 5 (n = 8), SAH plus placebo; group 6 (n = 8), SAH plus r-Hu-EPO. r-Hu-EPO, at a dose of 1,000 units/kg, and placebo were injected i.p. starting 5 min after inducing SAH and followed by clinical and pathological assessment 72 h later. Systemic administration of r-Hu-EPO produced significant increases in cerebrospinal fluid EPO concentrations (P < 0.001), and reduced vasoconstriction of the basilar artery (P < 0.05), ischemic neuronal damage (P < 0.001), and subsequent neurological deterioration (P < 0.05). These observations suggest that r-Hu-EPO may provide an effective treatment to reduce the post-SAH morbidity.

Effect of recombinant human erythropoietin on cerebral ischemia following experimental subarachnoid hemorrhage

Erythropoietin exerts a neuroprotective effect during cerebral ischemia. We investigated the effect of systemic administration of recombinant human erythropoietin in a rabbit model of subarachnoid hemorrhage-induced acute cerebral ischemia. The animals were divided into three groups: group 1, subarachnoid hemorrhage; group 2, subarachnoid hemorrhage plus placebo; group 3, subarachnoid hemorrhage plus recombinant human erythropoietin (each group, n=8). Experimental subarachnoid hemorrhage was produced by injecting autologous blood into the cisterna magna. Treatment with recombinant human erythropoietin and placebo was started 5 min after subarachnoid hemorrhage and was continued every 8 h for 24 h. Before the animals were killed, erythropoietin concentration was measured in the cerebrospinal fluid. The rabbits were killed 24 h after subarachnoid hemorrhage and ischemic brain injury was histologically evaluated. In group 3, the concentration of erythropoietin in the cerebrospinal fluid was significantly increased and a significant reduction in cortical necrotic neuron count was also observed. These findings may encourage the use of erythropoietin in the treatment of cerebral ischemia that often occurs in the early stage of subarachnoid hemorrhage.

Erythropoietin and erythropoietin receptor expression after experimental spinal cord injury encourages therapy by exogenous erythropoietin.

OBJECTIVE:Erythropoietin (EPO) is a pleiotropic cytokine originally identified for its role in erythropoiesis. Recent studies have demonstrated that EPO and its receptor (EPO-R) are expressed in the central nervous system, where EPO exerts neuroprotective functions. Because the expression of the EPO and EPO-R network is poorly investigated in the central nervous system, the aim of the present study was to investigate whether the resident EPO and EPO-R network is activated in the injured nervous system. METHODS:A well-standardized model of compressive spinal cord injury in rats was used. EPO and EPO-R expression was determined by immunohistochemical analysis at 8 hours and at 2, 8, and 14 days in the spinal cord of injured and noninjured rats. RESULTS:In noninjured spinal cord, weak immunohistochemical expression of EPO and EPO-R was observed in neuronal and glial cells as well as in endothelial and ependymal cells. In injured rats, a marked increase of expression of EPO and EPO-R was observed in neurons, vascular endothelium, and glial cells at 8 hours after injury, peaking at 8 days, after which it gradually decreased. Two weeks after injury, EPO immunoreactivity was scarcely detected in neurons, whereas glial cells and vascular endothelium expressed strong EPO-R immunoreactivity. CONCLUSION:These observations suggest that the local EPO and EPO-R system is markedly engaged in the early stages after nervous tissue injury. The reduction in EPO immunoexpression and the increase in EPO-R staining strongly support the possible usefulness of a therapeutic approach based on exogenous EPO administration.

Neuroprotective effect of erythropoietin and darbepoetin alfa after experimental intracerebral hemorrhage.

OBJECTIVEIntracerebral hemorrhage (ICH) is a devastating clinical syndrome for which no truly efficacious therapy has yet been identified. In preclinical studies, erythropoietin (EPO) and its long-lasting analog, darbepoetin alfa, have been demonstrated to be neuroprotective in several models of neuronal insult. The objectives of this study were to analyze whether the systemic administration of recombinant human EPO (rHuEPO) and its long-lasting derivative darbepoetin alfa expedited functional recovery and brain damage in a rat model of ICH. METHODSExperimental ICH was induced in rats by injecting autologous blood into the right striatum under stereotactic guidance. Subsequently, animals underwent placebo treatment, daily injections of rHuEPO, or weekly injections of darbepoetin alfa. Animals were killed 14 days after injury. RESULTSBoth rHuEPO and darbepoetin alfa were effective in reducing neurological impairment after injury, as assessed by the neurological tasks performed. rHuEPO- and darbepoetin alfa–treated animals exhibited a restricted brain injury with nearly normal parenchymal architecture. In contrast, the saline-treated group exhibited extensive cerebral cytoarchitectural disruption and edema. The number of surviving NeuN-positive neurons was significantly higher in the rats treated with rHuEPO and darbepoetin alfa compared with those that received saline (P < 0.05). CONCLUSIONThese results demonstrate that weekly administered darbepoetin alfa confers behavioral and histological neuroprotection after ICH in rats similar to that of daily EPO administration. Administration of EPO and its long-lasting recombinant forms affords significant neuroprotection in an ICH model and may hold promise for future clinical applications.

Assessment of human brain water content by cerebral bioelectrical impedance analysis: a new technique and its application to cerebral pathological conditions.

OBJECTIVE Total brain water content changes in several cerebral pathological conditions and the measurement of brain water content are important for the selection of appropriate therapeutic procedures. We present a quantitative, in vivo, bioelectrical impedance analysis (BIA) method and propose its use for the accurate assessment of brain water content among human subjects. METHODS Cerebral BIA is based on the conduction of an applied current in the brain parenchyma. Application of an excitatory current of 800 &mgr;A at 50 kHz, via two electrodes placed on the eyelids with the eyes closed, and detection of the voltage drop with two electrodes placed in the suboccipital region allow brain resistance and reactance to be measured. By means of an equation that considers cranial circumference and resistance, it is possible to quantify the total brain water content, expressed as the bioelectrical volume. Cerebral BIA was performed with a series of healthy volunteers (n = 100), for determination of average brain water content values. The method was then applied to 50 patients with brain tumors (n = 20), intracranial hemorrhage (n = 16), or hydrocephalus (n = 14), for assessment of changes in global brain water contents. Data were compared with those obtained for healthy volunteers. RESULTS Statistically significant differences (P < 0.001) were observed between the two groups. Mean brain water content values (expressed as bioelectrical volume values) were 38.2 ± 3.9 cm2/&OHgr; for healthy volunteers and 67.7 ± 13.1 cm2/&OHgr; for patients with cerebral pathological conditions. Statistically significant differences (P < 0.05) were also observed among patients with cerebral pathological conditions. CONCLUSION The results of this study suggest that BIA, applied to the cerebral parenchyma, is a valid method for the prediction of brain water contents under both normal and pathological conditions. However, further studies are needed to establish whether it is sensitive and reliable enough for future clinical applications.

Antisense Oligonucleotides Therapy in the Treatment of Cerebral Gliomas: A Review

Patients affected by cerebral gliomas, despite classical strategies adopted, show a very poor prognosis. Current treatment consists of regimens that include surgical debulking, radiation therapy, and systemic chemotherapy. However, the median survival after surgery and radiation therapy alone is 9 months, and systemic chemotherapy is minimally effective. Advances in molecular biology have better depicted the mechanisms involved in the genesis of cerebral gliomas and identified specific gene sequences to be targeted in the malignant cell genome. Gene expression can be blocked using various strategies. The concept of antisense-mediated gene inhibition has now emerged as a potentially powerful alternative or adjunct to conventional cancer chemotherapy. This strategy is able to block selectively glioma cells which interfer to gliomagenesis molecular pathways. The antisense molecules, delivered inside the brain, penetrate into glioma cells blocking specific genic functions. Antisense oligonucleotides are complementary to the target mRNA and this bind cause the block and/or the reduction of the encoded protein synthesis. Genes coding for growth factors and their receptors, proto-oncogenes, cellular proteases, kinases, and proteins important in cell cycle control and apoptosis represent ideal target for antisense oligonucleotides treatment. In this study, we report the most relevant findings of antisense oligonucleotides application in gliomas treatment.

Transsphenoidal microsurgical selective removal of multiple (triple) adenomas of the pituitary gland.

Summary This is the first case of multiple (triple) pituitary micro-adenomas documented by magnetic resonance imaging (MRI) in a living patient and treated by a transsphenoidal microsurgical approach. The patient, a 37-year-old woman, complained of a long history of bifrontal headache, weight gain and oligomenorrhea. Physical examination revealed moderate hirsutism and a slight fat pad overlying the vertebrae. Routine laboratory studies and endocrinological biochemical investigations were normal. A gadolinium-enhanced MRI of the pituitary region revealed three intrapituitary micro-adenomas. A transsphenoidal microsurgical approach to the pituitary gland was carried out and micro-adenomas were completely removed one at a time. One year follow-up showed complete resolution of clinical symptoms and signs and normal biochemical parameters of pituitary function.

Spinal Cord Compression by a Metastasizing Thymoma

Thymomas are rare slow growing tumours, which arise from thymic parenchyma and are characterised by local invasiveness. They represent 20% of all malignant mediastinal tumours. Based on the ratio of thymic versus epithelial elements, thymomas have been classi®ed into epithelial, lymphocytic, mixed and spindle cell types [3]. Currently, the Masaoka classi®cation is the most widely used staging system [4]. Approximately one-third of patients with thymoma has Myasthenia Gravis (MG), and one-tenth of patients a ̈ected by MG has a thymoma. The presence of MG adversely a ̈ects survival in some series but not in others. Invasive thymomas with a greater component of epithelial cells and association with MG have a poor prognosis. Only seven cases of metastases to the spinal cord have so far been described in the literature [2].

Landmarks for vertebral artery repositioning in bulbar compression syndrome: anatomic and microsurgical nuances.

OBJECTIVE: The purpose of this study was to better elucidate the anatomic relationship between the vertebral artery (VA) along with its perforating vessels and the brainstem to develop anatomic guidelines that would be helpful when decompressing medulla oblongata compressed by the VA. METHODS: Microanatomy dissection was performed in six formalin-fixed cadaveric heads. The VA, posteroinferior cerebellar artery (PICA), anteroinferior cerebellar artery (AICA), and lower brainstem perforators were examined under magnification using a surgical microscope. The outer diameters of the VA, PICA, and AICA were measured. The distance between the VA, lying within the lateral cerebellomedullary cistern, and the medulla oblongata was quantified. The lower brainstem perforating vessels were examined in relation to their course, outer diameter, and length. RESULTS: In four of six brains, the left VA was dominant, presenting an outer diameter at least 0.8 mm larger than the contralateral VA. The average distance between the VA and the medulla oblongata was 3 mm. The perforating branches presented a mean outer diameter of 0.7 mm. In particular, perforators arising from the VA and PICA (Groups 1 and 2) presented an average outer diameter of 0.2 mm and an average length of 7 mm. Perforating vessels arising from the AICA and vertebrobasilar junction (Groups 3 and 4) presented an average outer diameter of 0.4 mm and an average length of 12 mm. CONCLUSION: This work provides new information that may be useful to minimize the risk of injury of perforators when operating on medulla oblongata compression by the VA.

Non-Traumatic Sphenoidal Intradiploic Arachnoid Cyst as a Cause of Trigeminal Neuralgia A Case Report

Non-traumatic intradiploic arachnoid cyst is a rare condition. We describe a young man with typical trigeminal neuralgia and intradiploic arachnoid cyst at the greater wing of the sphenoid. The patient was successfully treated with medical therapy. To our knowledge, this is the first case report of a possible correlation between trigeminal neuralgia and intraosseous arachnoid cyst. We describe the clinical case, the possible pathogenetic mechanism and briefly review the literature.