Prevention of subarachnoid fibrosis after subarachnoid haemorrhage with urokinase

Novel therapeutics for hydrocephalus: Insights from animal models

Hydrocephalus is a cerebrospinal fluid physiological disorder that causes ventricular dilation with normal or high intracranial pressure. The current regular treatment for hydrocephalus is cerebrospinal fluid shunting, which is frequently related to failure and complications. Meanwhile, considering that the current nonsurgical treatments of hydrocephalus can only relieve the symptoms but cannot eliminate this complication caused by primary brain injuries, the exploration of more effective therapies has become the focus for many researchers. In this article, the current research status and progress of nonsurgical treatment in animal models of hydrocephalus are reviewed to provide new orientations for animal research and clinical practice.

Intraventricular administration of urokinase as a novel therapeutic approach for communicating hydrocephalus

Fibrosis of the subarachnoid space (SAS) after infection, inflammation, or hemorrhage can impair cerebrospinal fluid absorption and circulation, causing diffuse ventricular dilatation. In the present study, we tested the hypothesis that urokinase (also known as urokinase-type plasminogen activator [uPA]), a fibrinolytic agent, attenuates fibrosis and ventriculomegaly in a rat model of kaolin-induced communicating hydrocephalus and thus may have potential as a therapy for these conditions. Thirty microliters of sterile 25% kaolin suspension was injected into the basal cisterns of adult Sprague-Dawley rats to induce hydrocephalus, and 2 intraventricular injections of either uPA or vehicle (saline) were administered immediately and 3 days thereafter. Ventricular volumes were measured by magnetic resonance imaging (MRI) on days 3, 14, and 28 after kaolin injection. Fibrosis and reactive astrogliosis were evaluated on day 28 by immunofluorescence and Western blotting. Neurocognitive features were tested using the Morris water maze from days 23 to 28. MRI analysis demonstrated that kaolin administration successfully induced hydrocephalus in rats and that uPA treatment significantly attenuated ventricular enlargement. In addition, uPA inhibited the deposition of laminin and fibronectin, extracellular matrix molecules, in the SAS, attenuated gliosis, and improved learning and memory in kaolin-treated rats. Therefore, we concluded that uPA prevents the development of kaolin-induced communicating hydrocephalus by preventing the development of subarachnoid fibrosis and by eliciting improvements in neurocognition. The results of this study indicate that uPA may be a novel clinical therapy for communicating hydrocephalus.

CT-guided stereotactic fibrinolysis of spontaneous and hypertensive cerebellar hemorrhage: long-term results

The surgical indication for spontaneous cerebellar hemorrhage is not as controversial as the operative management of intracranial hemorrhage. Timing of the operation is crucial: intervening too early can produce an additional strain on the patient and an increased risk, while waiting too long to evacuate the hematoma can be fatal. This dilemma may be a factor in the relatively high mortality and morbidity rates following both operative and conservative treatment that have been reported in the literature (42.5% and 30%, respectively). In long-term studies on 14 patients, the authors have shown that stereotactic puncture and fibrinolysis for cerebellar hemorrhage is a valuable alternative to treatments used currently. The method consists of computerized tomography (CT)-guided stereotactic puncture and partial evacuation of the hematoma. After fibrinolysis with urokinase, the residual hematoma can be completely evacuated via a catheter introduced into the cavity of the hematoma. Only one of the 14 patients died in the direct postoperative phase; the remaining patients were enjoying a good to very good quality of life 6 months after the acute event. Two patients subsequently died as a result of pneumonia and cerebral infarction, respectively; both conditions were unrelated to the hemorrhage. The authors conclude that the CT-guided stereotactic method is simple, effective, and safe, and can be applied to patients of any age.

Plasticity of the brain in respect of functional restoration after subarachnoid haemorrhage

Subarachnoid haemorrhage caused by aneurysmal rupture constitutes a great impact on the brain and on the intracranial content as a whole, with emphasis on the subarachnoid spaces and arteries. The rupture is followed by a wide range of pathological alterations in the neural function and an outcome varying from neglected signs subsiding in a few days to immediate death. Two main factors seem to influence the different events after subarachnoid bleeding. One is the rupture itself which can be extremely variable in severity and in its immediate as well as late consequences. The other is the ability of all parts of the intracranial content to recover. In order to understand either of both the other should also be looked at and both have to be dealt with if we are to treat patients with an aneurysmal rupture properly. For this reason a grading of rupture will be given in respect of some characteristic events in the light of neural restoration. Clearing of CSF, resolution of brain oedema, restoration of impaired CBF, absorption of cisternal and parenchymal haematoma are all of importance. The majority of lesions which developed after the rupture are not fatal or irreversible and even the neural tissue destroyed by the impact or late ischaemia can be functionally replaced. Possible methods of treatment for attaining this functional restoration will be discussed.

Polarization microscopic investigation of subarachnoid fibrosis after subarachnoid haemorrhage

The author used the polarization microscope and topo-optical reactions such as phenol reaction, collagen-specific sulphation, and picrosirius red F 3 BA staining to investigate the nature of subarachnoid fibrosis after experimental subarachnoid haemorrhage. It is strongly suggested that the subarachnoid fibrotic deposits--which here analysed in a previous study by scanning electronmicroscopy--contain a high amount of collagen as a main component both three weeks and three months after the SAH.

Effect of antifibrinolytic therapy on subarachnoid fibrosis in dogs after experimental subarachnoid haemorrhage

The effect of antifibrinolytic therapy on posthaemorrhagic subarachnoid fibrosis was observed experimentally in dogs with the scanning electron microscope (SEM). The subchronic subjects, given intravenous injections of tranexamic acid (1 mg/day) for 12 days and sacrificed 3 weeks after cisternal blood injection, showed residual clot with thick fibrosis, especially around the haemorrhage. The chronic subjects, to which the same procedure was applied and which were sacrificed three months after cisternal blood injection, showed significant increases in the subarachnoid fibrosis, most remarkably in the parasagittal region. Tranexamic acid is widely used for preventing the recurrence of subarachnoid haemorrhage. However, it was revealed in this study that antifibrinolytic therapy might increase chronic posthaemorrhagic subarachnoid fibrosis, which is considered to be responsible for communicating hydrocephalus by disturbing epicortical CSF flow.