Marina Quartu

Neuropeptides and morphological changes in cisplatin-induced dorsal root ganglion neuronopathy.

Dorsal root ganglia (DRG) neuronopathy was induced in rats by chronic treatment (2 mg/kg twice a week for nine injections) with the antineoplastic drug cisplatin. Morphological alterations and changes in peptide [calcitonin gene-related peptide (CGRP), substance P, galanin (Gal), and somatostatin] concentration were studied in the DRG, the spinal cord, and the sciatic nerve. Peptide concentration was increased in DRG neurons, with CGRP and Gal showing the highest increase. Conversely, in the sciatic nerve there was a general decrease in peptide content. In DRG a reduction in the nuclear, cytoplasmic, and nucleolar areas of primary sensory neurons was evident and was accompanied by clear-cut aspects of nucleolar structural damage. In peripheral nerves only extensive morphometric determinations could evidence a reduction in nerve conduction velocities and impairment in pain detection and coordination. Some of the nerve fibers presented axonal and adaxonal accumulations, suggesting the presence of an axonopathy. These results confirm that DRG cells are the primary target of cisplatin-induced neurotoxicity. Milder alterations can be detected in peripheral nerves. The increase in peptide concentration in DRG is probably due to cisplatin-related damage to the axonal transport system rather than to an increased synthesis.

Calcitonin gene-related peptide in the human trigeminal sensory system at developmental and adult life stages: immunohistochemistry, neuronal morphometry and coexistence with substance P.

The distribution of calcitonin gene-related peptide (CGRP) has been examined by the indirect immunofluorescence technique in the Gasserian ganglion and spinal nucleus of the human trigeminal nerve. In the ganglion CGRP is present in almost 50% of primary sensory neurons, in varicose and non-varicose nerve fibres and in pericellular basket-like plexuses around non-immunoreactive ganglionic perikarya. Morphometric analysis reveals that the CGRP-positive neuronal population is heterogeneous in cell size. Observation of specimens from subjects at fetal, perinatal and adult life stages reveals that the percentage of CGRP-immunoreactive cells reaches a maximum at perinatal stages and then remains constant, declining only in old age. Pericellular basket-like nerve fibres are detectable only in fetal and pre-term and full-term newborn tissue. Coexistence between CGRP and substance P (SP) occurs, SP being present in about one quarter of the CGRP-immunoreactive neurons and CGRP being localized in a little more than half of the SP-immunoreactive neurons. However, perikarya, nerve fibres and pericellular fibres containing only one or other peptide are also present. Bundles of immunoreactive fibres and dot-like nerve terminals occur in the spinal tract and superficial and deep regions of the spinal trigeminal nucleus. A particularly dense plexus is present in the peripheral nuclear layers. Double immunostaining shows a similar regional distribution for SP. However, in inner substantia gelatinosa the density of CGRP-immunoreactive fibres is much higher than that of SP-immunoreactive ones. The results obtained add information to our knowledge of the organization of neurochemically identified neurons in the human trigeminal sensory system.

Bortezomib-induced painful peripheral neuropathy: an electrophysiological, behavioral, morphological and mechanistic study in the mouse

Bortezomib is the first proteasome inhibitor with significant antineoplastic activity for the treatment of relapsed/refractory multiple myeloma as well as other hematological and solid neoplasms. Peripheral neurological complications manifesting with paresthesias, burning sensations, dysesthesias, numbness, sensory loss, reduced proprioception and vibratory sensitivity are among the major limiting side effects associated with bortezomib therapy. Although bortezomib-induced painful peripheral neuropathy is clinically easy to diagnose and reliable models are available, its pathophysiology remains partly unclear. In this study we used well-characterized immune-competent and immune-compromised mouse models of bortezomib-induced painful peripheral neuropathy. To characterize the drug-induced pathological changes in the peripheral nervous system, we examined the involvement of spinal cord neuronal function in the development of neuropathic pain and investigated the relevance of the immune response in painful peripheral neuropathy induced by bortezomib. We found that bortezomib treatment induced morphological changes in the spinal cord, dorsal roots, dorsal root ganglia (DRG) and peripheral nerves. Neurophysiological abnormalities and specific functional alterations in Aδ and C fibers were also observed in peripheral nerve fibers. Mice developed mechanical allodynia and functional abnormalities of wide dynamic range neurons in the dorsal horn of spinal cord. Bortezomib induced increased expression of the neuronal stress marker activating transcription factor-3 in most DRG. Moreover, the immunodeficient animals treated with bortezomib developed a painful peripheral neuropathy with the same features observed in the immunocompetent mice. In conclusion, this study extends the knowledge of the sites of damage induced in the nervous system by bortezomib administration. Moreover, a selective functional vulnerability of peripheral nerve fiber subpopulations was found as well as a change in the electrical activity of wide dynamic range neurons of dorsal horn of spinal cord. Finally, the immune response is not a key factor in the development of morphological and functional damage induced by bortezomib in the peripheral nervous system.

Tissue distribution of Ret, GFRalpha-1, GFRalpha-2 and GFRalpha-3 receptors in the human brainstem at fetal, neonatal and adult age

Occurrence and localization of receptor components of the glial cell line-derived neurotrophic factor (GDNF) family ligands, the Ret receptor tyrosine kinase and the GDNF family receptor (GFR) alpha-1 to -3, were examined by immunohistochemistry in the normal human brainstem at fetal, neonatal, and adult age. Immunoreactive elements were detectable at all examined ages with uneven distribution and consistent pattern for each receptor. As a rule, the GFRalpha-1 and GFRalpha-2 antisera produced the most abundant and diffuse tissue labelling. Immunoreactive perikarya were observed within sensory and motor nuclei of cranial nerves, dorsal column nuclei, olivary nuclear complex, reticular formation, pontine nuclei, locus caeruleus, raphe nuclei, substantia nigra, and quadrigeminal plate. Nerve fibers occurred within gracile and cuneate fasciculi, trigeminal spinal tract and nucleus, facial, trigeminal, vestibular and oculomotor nerves, solitary tract, medial longitudinal fasciculus, medial lemniscus, and inferior and superior cerebellar peduncles. Occasionally, glial cells were stained. Age changes were appreciable in the distribution pattern of each receptor. On the whole, in the grey matter, labelled perikarya were more frequently observed in pre- and perinatal than in adult specimens; on the other hand, in discrete regions, nerve fibers and terminals were abundant and showed a plexiform arrangement only in adult tissue; finally, distinct fiber systems in the white matter were immunolabelled only at pre- and perinatal ages. The results obtained suggest the involvement of Ret and GFRalpha receptors signalling in processes subserving both the organization of discrete brainstem neuronal systems during development and their functional activity and maintenance in adult life.

Neurotrophin-like immunoreactivity in the human hippocampal formation

The immunohistochemical occurrence and localisation of the neurotrophins nerve growth factor, brain-derived neurotrophic factor (BDNF), neurotrophin-4, and neurotrophin-3 is described in the human post-mortem hippocampal formation from subjects aged 23 weeks of gestation to 68 years. Labeled neuronal cell bodies and processes were detectable for each neurotrophin at all examined ages with age-related changes in their distribution pattern. As a general rule, a higher number of immunoreactive perikarya was found in subjects at pre- and perinatal ages than in adults. At variance with the other neurotrophins, the BDNF antiserum labelled also extensive nerve fibre systems, whose occurrence and distribution widened with age. The results obtained provide a morphological ground in support to the concept that the neurotrophins play a functional role in the human hippocampal circuitry throughout life.

Topographical localization of glial cell line-derived neurotrophic factor in the human brain stem: an immunohistochemical study of prenatal, neonatal and adult brains

As a step towards the identification of the neuronal populations responsive to glial cell line-derived neurotrophic factor (GDNF) in the human nervous system and their changes with age, this study reports on the immunohistochemical localization of the protein GDNF in the autoptic normal human brain stem of pre- and full-term newborns and adult subjects. Two different anti-GDNF polyclonal antibodies were used. Western blot analysis on homogenates of human and rat brain and recombinant human GDNF resulted in differential detection of monomeric and dimeric forms of the proteins. The ABC immunohistochemical technique on cryostat tissue sections showed an uneven distribution of GDNF-like immunoreactive nerve fibers and terminals and neuronal cell bodies. Immunoreactive elements were mainly localized to the spinal trigeminal, cuneate, solitary, vestibular, and cochlear sensory nuclei, dorsal motor nucleus of the vagus nerve, ventral grey column, hypoglossal nucleus, dorsal and ventrolateral medullary reticular formation, pontine subventricular grey and locus coeruleus, lateral regions of the rostral pontine tegmentum, tectal plate, trochlear nucleus, dorsal and median raphe nuclei, caudal and rostral linear nuclei, cuneiform nucleus, and substantia nigra. Comparison between pre- and full-term newborns and adult subjects revealed changes with age in density of positive innervation and frequency of immunoreactive perikarya. The results obtained provide detailed information on the occurrence of GDNF-like immunoreactive neurons in the human brain stem and suggest that the protein is present in a variety of neuronal systems, which subserve different functional activities, at developmental ages and in adult brains.

Neurotrophin-like immunoreactivity in the human trigeminal ganglion.

THE localization of the neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4), and neurotrophin-3 (NT-3) was demonstrated immunohistochemically in discrete neuronal subsets of the human trigeminal ganglion at ages ranging from 23 weeks of gestation to adulthood. Neurotrophin-containing subpopulations partially overlapped with each other and with those immunoreactive for the relevant trk receptor. Glial elements could also be immunostained, labelled satellite cells being particularly abundant in NT-3 stained sections. These results suggest that the neurotrophins are of functional significance for the human trigeminal primary sensory neurones throughout life. Their localization in the ganglion cellular components supports their function as target-derived trophic factors and as molecules effective in autocrine/paracrine interactions.

Effect of acute administration of Pistacia lentiscus L. essential oil on rat cerebral cortex following transient bilateral common carotid artery occlusion

BackgroundIschemia/reperfusion leads to inflammation and oxidative stress which damages membrane highly polyunsaturated fatty acids (HPUFAs) and eventually induces neuronal death. This study evaluates the effect of the administration of Pistacia lentiscus L. essential oil (E.O.), a mixture of terpenes and sesquiterpenes, on modifications of fatty acid profile and endocannabinoid (eCB) congener concentrations induced by transient bilateral common carotid artery occlusion (BCCAO) in the rat frontal cortex and plasma.MethodsAdult Wistar rats underwent BCCAO for 20 min followed by 30 min reperfusion (BCCAO/R). 6 hours before surgery, rats, randomly assigned to four groups, were gavaged either with E.O. (200 mg/0.45 ml of sunflower oil as vehicle) or with the vehicle alone.ResultsBCCAO/R triggered in frontal cortex a decrease of docosahexaenoic acid (DHA), the membrane highly polyunsaturated fatty acid most susceptible to oxidation. Pre-treatment with E.O. prevented this change and led further to decreased levels of the enzyme cyclooxygenase-2 (COX-2), as assessed by Western Blot. In plasma, only after BCCAO/R, E.O. administration increased both the ratio of DHA-to-its precursor, eicosapentaenoic acid (EPA), and levels of palmytoylethanolamide (PEA) and oleoylethanolamide (OEA).ConclusionsAcute treatment with E.O. before BCCAO/R elicits changes both in the frontal cortex, where the BCCAO/R-induced decrease of DHA is apparently prevented and COX-2 expression decreases, and in plasma, where PEA and OEA levels and DHA biosynthesis increase. It is suggested that the increase of PEA and OEA plasma levels may induce DHA biosynthesis via peroxisome proliferator-activated receptor (PPAR) alpha activation, protecting brain tissue from ischemia/reperfusion injury.

Somatostatin, galanin and peptide histidine isoleucine in the newborn and adult human trigeminal ganglion and spinal nucleus: immunohistochemistry, neuronal morphometry and colocalization with substance P.

By means of indirect immunofluorescence the neuropeptides somatostatin, galanin and peptide histidine isoleucine were localized in cell bodies, nerve fibres and terminal-like elements in the ganglion and spinal nucleus of the human trigeminal nerve in perinatal and adult ages. No immunoreactivity to vasoactive intestinal polypeptide was observed. In the gasserian ganglion somatostatin-, galanin- and peptide histidine isoleucine-containing neurons and nerve fibres occurred frequently in pre- and full-term newborns, but were scarce to absent in adults. Somatostatin- and galanin-positive pericellular basket-like structures around non-immunoreactive perikarya were observed in newborn specimens. Immunoreactivity to somatostatin, galanin and peptide histidine isoleucine labelled nerve fibers and punctate and felt-like nerve terminals in the pars interpolaris and subnucleus caudalis of the spinal trigeminal nucleus, with immunostaining and distribution patterns characteristic for each peptide. In addition, somatostatin-containing neuronal cell bodies frequently were detected. At variance with those containing somatostatin, the number of galanin- and peptide histidine isoleucine-like immunoreactive elements were dramatically reduced in the adult tissue compared to the newborn one. Double immunostaining revealed that each of the three peptides partially colocalizes with substance P, the degree of coexistence being very low for somatostatin/substance P and high for galanin/substance P and peptide histidine isoleucine/substance P both in the gasserian ganglion and in the spinal nucleus. The results obtained suggest that somatostatin, galanin and peptide histidine isoleucine may play functional roles in primary sensory neurons and at the first synaptic level of the human trigeminal sensory system.

TRPV1, CGRP and SP in scalp arteries of patients suffering from chronic migraine

Objective The transient receptor potential vanilloid type-1 receptor (TRPV1) and the neuropeptides calcitonin gene-related peptide (CGRP) and substance P (SP) appear to be differently involved in migraine pain. A role of neurovascular scalp structures is also suggested by several data. We performed a quantitative study of TRPV1-like immunoreactive (LI), CGRP-LI and SP-LI innervation of scalp arterial samples from patients affected with chronic migraine (CM). Methods Short segments of scalp arteries were collected from 17 participants undergoing vascular surgery for treatment-resistant CM and from 6 controls who underwent neurosurgery for various indications. The immunoreactivity of the arterial innervation to TRPV1, CGRP, SP and to the pan-neuronal marker protein gene product 9.5 (PGP9.5) was examined. Immunoreactive nerve fibres in vessel cross-sections were quantified by computerised image analysis. Results A significant increase of TRPV1-LI nerve fibres was found in the arterial wall from CM compared with control patients (p<0.05), while no significant difference was found for CGRP and SP. Conclusions This study yields the first evidence for the existence of a TRPV1-LI innervation in human scalp arteries and provides the first quantitative assessment of the TRPV1-LI, CGRP-LI and SP-LI innervation of those vessels. The increase of TRPV1-LI periarterial nociceptive fibres of scalp arteries may represent, at least in some participants, a structural condition favouring CM (and possibly migraine), for example, by causing a higher sensitivity to algogenic agents.