Melatonin secretion in normal pressure hydrocephalus after cerebral aneurysm rupture--investigation before and after ventriculoperitoneal shunt

Melatonin ameliorates blood-brain barrier permeability, glutathione, and nitric oxide levels in the choroid plexus of the infantile rats with kaolin-induced hydrocephalus

Hydrocephalus is a disabling disease for children, but current data concerning the effects of melatonin on ventricular enlargement are still limited. We have investigated the changes in the choroid plexuses (CPs) of ventricles and blood-brain barrier (BBB) of hydrocephalic rats. Forty-five Swiss Albino rats at age 2 weeks were divided into three equal groups: control, hydrocephalus, and melatonin-treated hydrocephalus groups. Hydrocephalus was induced by kaolin injection into the cisterna magna of all pups except control group and melatonin was given at a daily dose of 0.5 mg/100 g body weight for 4 weeks. At the end of the study, one animal from each group was examined using a gamma camera to study the disruption of BBB due to hydrocephalus. All animals were then killed for assay of glutathione (GSH) and nitric oxide (NO), as well as histological study of the CPs during the hydrocephalus. We observed an increased BBB activity was found in hydrocephalus group, while melatonin reversed these changes. It was found that NO concentration was elevated in hydrocephalus group and melatonin partly abolished the increased levels of NO. In contrast, GSH levels were significantly decreased in hydrocephalus group, while melatonin increased the tissue GSH level (p<0.01). Histologically, there was a significant alteration in the CPs of the ventricles of hydrocephalic animals, but it was regressed after melatonin treatment in consistent with the gross morphological changes related to hydrocephalus. In conclusion, our results clearly demonstrated for the first time the neuroprotective effects of melatonin upon hydrocephalus-induced CP changes in infantile rats, but further studies are needed to suggest melatonin as a candidate protective drug in children.

Ventricular cerebrospinal fluid melatonin concentrations investigated with an endoscopic technique

The role of melatonin in humans still remains unclear. Uncertainties persist about its effects on neurophysiology regarding its levels in human cerebrospinal fluid (CSF), as the bulk of knowledge on this subject mainly derives from studies conducted on animals. In this study, CSF was micro-sampled with a simple, new method from each cerebral ventricle of patients undergoing neuroendoscopy for hydrocephalus. Our purpose was to measure CSF melatonin levels and determine possible differences in its concentration among various significant areas in the cerebral ventricles (e.g. pineal recess, pituitary recess, lateral ventricle, fourth ventricle) and lumbar cistern. From 2002 to 2004, 10 hydrocephalic patients were operated on using a neuroendoscopic technique. The CSF specimens were investigated for melatonin concentrations (free plus protein-bound) after deproteinization; the measurement technique was high-performance liquid chromatography. The preliminary data obtained with this endoscopic micro-sampling technique (applied to humans for the first time) suggest that melatonin is more concentrated within the ventricles and its highest concentration is found in the third ventricle (IIIv), although the difference detected between the CSF of the IIIv and that of the pineal recess was not significant.

Biomarkers in chronic adult hydrocephalus

Awareness of the importance of chronic adult hydrocephalus has been raised again with the recent emergence of epidemiological studies. It is estimated that between 5 and 10% of patients suffering from dementia might, in fact, have chronic hydrocephalus. Although, surgical diversion of the cerebrospinal fluid (CSF) represents the only known procedure able to treat the symptoms of this condition, the selection of surgical patients has always been problematic. In the last 40 years, we have become wiser in using appropriate diagnostic tests for the selection of these patients; however, the area of biological markers has so far been overlooked in this condition, in contrast to that for other neurodegenerative disorders and dementias. Biomarkers are biological substances that may be used to indicate either the onset or the presence, and the progression of a clinical condition, being closely linked to its pathophysiology. In such a setting they might assist in the more appropriate selection of patients for shunt surgery. In this article, we have reviewed research carried out in the last 25 years regarding the identification of serum and CSF biomarkers for chronic hydrocephalus, discussed the potential for each one, and finally discussed the limitations for use, as well as future directions and possibilities in this field. It is concluded that tumour-necrosis factor, tau protein, lactate, sulfatide and neurofilament triple protein are the most promising CSF markers for chronic hydrocephalus. At present however, none of these meet the criteria required to justify a change clinical practice. In the future, collaborative multi-centre projects will be needed to obtain more substantial data that overcome the problems that arise from small individual and uncoordinated studies.

Melatonin: a clinical perspective

Over the last several decades the pineal gland has emerged as an active neuroendocrine transducer of important environmental information. However, the current understanding of the function of its major hormone, melatonin, in humans remains ill defined and based exclusively on correlative observations. In a similar manner, the multitude of phenomenological descriptions of the effects of exogenous melatonin is contrasted by the limited understanding of the underlying mechanisms and the lack of firmly established clinical applications for the hormone. Future randomized, double-blind, placebo-controlled clinical studies will be necessary to determine the precise indications, treatment regimens, and safety of melatonin in clinical practice. The recent rapid progress in the area of melatonin research should lead to a better understanding of its role in human health and disease.