Intra-epidermal nerve endings progress within keratinocyte cytoplasmic tunnels in normal human skin

Intra-epidermal nerve endings, responsible for cutaneous perception of temperature, pain and itch, are conventionally described as passing freely between keratinocytes, from the basal to the granular layers of the epidermis. However, the recent discovery of keratinocyte contribution to cutaneous nociception implies that their anatomical relationships are much more intimate than what has been described so far. By studying human skin biopsies in confocal laser scanning microscopy, we show that intra-epidermal nerve endings are not only closely apposed to keratinocytes, but can also be enwrapped by keratinocyte cytoplasms over their entire circumference and thus progress within keratinocyte tunnels. As keratinocytes must activate intra-epidermal nerve endings to transduce nociceptive information, these findings may help understanding the interactions between the keratinocytes and nervous system. The discovery of these nerve portions progressing in keratinocyte tunnels is a strong argument to consider that contacts between epidermal keratinocytes and intra-epidermal nerve endings are not incidental and argue for the existence of specific and rapid paracrine communication from keratinocytes to sensory neurons.

Redistribution of Cav2.1 channels and calcium ions in nerve terminals following end-to-side neurorrhaphy: ionic imaging analysis by TOF-SIMS

The P/Q-type voltage-dependent calcium channel (Cav2.1) in the presynaptic membranes of motor nerve terminals plays an important role in regulating Ca²⁺ transport, resulting in transmitter release within the nervous system. The recovery of Ca²⁺-dependent signal transduction on motor end plates (MEPs) and innervated muscle may directly reflect nerve regeneration following peripheral nerve injury. Although the functional significance of calcium channels and the levels of Ca²⁺ signalling in nerve regeneration are well documented, little is known about calcium channel expression and its relation with the dynamic Ca²⁺ ion distribution at regenerating MEPs. In the present study, end-to-side neurorrhaphy (ESN) was performed as an in vivo model of peripheral nerve injury. The distribution of Ca²⁺ at regenerating MEPs following ESN was first detected by time-of-flight secondary ion mass spectrometry, and the specific localization and expression of Cav2.1 channels were examined by confocal microscopy and western blotting. Compared with other fundamental ions, such as Na⁺ and K⁺, dramatic changes in the Ca²⁺ distribution were detected along with the progression of MEP regeneration. The re-establishment of Ca²⁺ distribution and intensity were correlated with the functional recovery of muscle in ESN rats. Furthermore, the re-clustering of Cav2.1 channels after ESN at the nerve terminals corresponded with changes in the Ca²⁺ distribution. These results indicated that renewal of the Cav2.1 distribution within the presynaptic nerve terminals may be necessary for initiating a proper Ca²⁺ influx and shortening the latency of muscle contraction during nerve regeneration.

Secreted herpes simplex virus-2 glycoprotein G modifies NGF-TrkA signaling to attract free nerve endings to the site of infection

Herpes simplex virus type 1 (HSV-1) and HSV-2 are highly prevalent viruses that cause a variety of diseases, from cold sores to encephalitis. Both viruses establish latency in peripheral neurons but the molecular mechanisms facilitating the infection of neurons are not fully understood. Using surface plasmon resonance and crosslinking assays, we show that glycoprotein G (gG) from HSV-2, known to modulate immune mediators (chemokines), also interacts with neurotrophic factors, with high affinity. In our experimental model, HSV-2 secreted gG (SgG2) increases nerve growth factor (NGF)-dependent axonal growth of sympathetic neurons ex vivo, and modifies tropomyosin related kinase (Trk)A-mediated signaling. SgG2 alters TrkA recruitment to lipid rafts and decreases TrkA internalization. We could show, with microfluidic devices, that SgG2 reduced NGF-induced TrkA retrograde transport. In vivo, both HSV-2 infection and SgG2 expression in mouse hindpaw epidermis enhance axonal growth modifying the termination zone of the NGF-dependent peptidergic free nerve endings. This constitutes, to our knowledge, the discovery of the first viral protein that modulates neurotrophins, an activity that may facilitate HSV-2 infection of neurons. This dual function of the chemokine-binding protein SgG2 uncovers a novel strategy developed by HSV-2 to modulate factors from both the immune and nervous systems.

[Case-control study on the relationship of chronic low back pain of facet joint origin with the distribution of nerve endings and neuropeptide: a quantitative histological analysis]

OBJECTIVE

To investigate the density and distribution of nerve endings and neuropeptide Y (NPY) in lumbar facet joints of patients with low back pain.

METHODS

Fifteen patients without low back pain were selected as control group (group A). Facet joint samples in group A were obtained during the operation or lumbar spinal canal tumor they suffered from. Those patients with low back pain were divided into three groups according to their different origins of pain, such as not from facet joint (group B, 15 patients) ,from facet joint only (group C, 20 patients), or from facet joint partially (group D, 20 patients). Different origins were determined by VAS after facet joint block. The density and distribution of nerve ending and neuropeptide in the capsular tissues were analyzed by a modified gold chloride staining and immunochemistry respectively.

RESULTS

Compared with the ones in group A and B, the fact joints in group C and D were more inclined to be degenerated and got more nerve endings. NPY was expressed mainly in the facet joint of patients with low back pain in group C and D. In addition, there was a significant relationship between the distribution of nerve endings and NPY expression,while none of them were related with MRI Fujiwara grade of facet joint.

CONCLUSION

These results suggest that the number of mechanoreceptors, neural sprouting and secreted peptides in the facet joint capsules vary with the change of mechanical or nociceptive stimulation, which may promote the development of low back pain in return.

Molecular mechanism of acrylamide neurotoxicity: lessons learned from organic chemistry

BACKGROUND

Acrylamide (ACR) produces cumulative neurotoxicity in exposed humans and laboratory animals through a direct inhibitory effect on presynaptic function.

OBJECTIVES

In this review, we delineate how knowledge of chemistry provided an unprecedented understanding of the ACR neurotoxic mechanism. We also show how application of the hard and soft, acids and bases (HSAB) theory led to the recognition that the α,β-unsaturated carbonyl structure of ACR is a soft electrophile that preferentially forms covalent bonds with soft nucleophiles.

METHODS

In vivo proteomic and in chemico studies demonstrated that ACR formed covalent adducts with highly nucleophilic cysteine thiolate groups located within active sites of presynaptic proteins. Additional research showed that resulting protein inactivation disrupted nerve terminal processes and impaired neurotransmission.

DISCUSSION

ACR is a type-2 alkene, a chemical class that includes structurally related electrophilic environmental pollutants (e.g., acrolein) and endogenous mediators of cellular oxidative stress (e.g., 4-hydroxy-2-nonenal). Members of this chemical family produce toxicity via a common molecular mechanism. Although individual environmental concentrations might not be toxicologically relevant, exposure to an ambient mixture of type-2 alkene pollutants could pose a significant risk to human health. Furthermore, environmentally derived type-2 alkenes might act synergistically with endogenously generated unsaturated aldehydes to amplify cellular damage and thereby accelerate human disease/injury processes that involve oxidative stress.

CONCLUSIONS

These possibilities have substantial implications for environmental risk assessment and were realized through an understanding of ACR adduct chemistry. The approach delineated here can be broadly applied because many toxicants of different chemical classes are electrophiles that produce toxicity by interacting with cellular proteins.

[Palisade endings of extraocular muscles in eyes with congenital nystagmus]

OBJECTIVE

To evaluate the morphology, distribution and function of palisade endings (PE) in human extraocular muscles (EOM), and observe the alterations in eyes with congenital nystagmus (CN). The etiology and pathogenesis of CN were also investigated.

METHODS

It was a experimental study. The distal myotendinous junctions of the EOM were obtained during operation for CN (CN group) and concomitant strabismus (control group). The samples from patients with similar age and same extraction sites in the two groups were compared. The muscles cut during operation were immediately put into 4% glutaraldehyde fixative solution. And 1-2 transverse bands of tissue were cut every 1 mm from tendon insertion for specimens processing. The ultrastructure of EOM and PE in the two groups was observed by transmission electron microscopy. The distal parts of EOM cut during operation were put into 4% paraformaldehyde promptly. Myotendinous junction region whole mounts were labeled with antibodies against choline acetyltransferase (ChAT). Muscle fibers were counterstained with phalloidin. And longitudinal and transverse cryostat serial sections were cut at 25 µm and analyzed by confocal laser scanning microscopy. The ChAT expression, morphology and distribution of PE were observed. The same fragment of myotendinous junction in the two groups was selected. After the total protein was extracted, ChAT was detected by western blot. The expression level of ChAT was analyzed.

RESULTS

Compared with the controls, the ultrastructure in the CN group had considerable variations. The axon of PE was swelled and deformed partly. The electron density was increased and presented as addicted to osmic acid. In the muscle cells, mitochondria was swelled, and sarcoplasmic reticulum was dilated. All PE exhibited ChAT immunoreactivity in human EOM. In the longitudinal section, nerve fibers extended from the muscle into the tendon, looped back and divided into several terminal arborizations (palisade endings) around the muscle fiber tip. The PE of medial rectus were richest at the location 3 - 4 mm from tendon insertion. In the cross section, the amount of PE in the CN group was higher than the control group (t = -5.613, P < 0.05). The expression level of ChAT in the CN group was higher than the control group (t = -3.730, P < 0.05).

CONCLUSIONS

Palisade endings in myotendinous junction of human EOM are cholinergic nerves, which might innervate the contraction of EOM. Significant changes of palisade endings in the EOM of the CN subjects may affect eye movement.

Apoptosis signal-regulating kinase 1 mediates MPTP toxicity and regulates glial activation

Apoptosis signal-regulating kinase 1 (ASK1), a member of the mitogen-activated protein kinase 3 family, is activated by oxidative stress. The death-signaling pathway mediated by ASK1 is inhibited by DJ-1, which is linked to recessively inherited Parkinson's disease (PD). Considering that DJ-1 deficiency exacerbates the toxicity of the mitochondrial complex I inhibitor 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), we sought to investigate the direct role and mechanism of ASK1 in MPTP-induced dopamine neuron toxicity. In the present study, we found that MPTP administration to wild-type mice activates ASK1 in the midbrain. In ASK1 null mice, MPTP-induced motor impairment was less profound, and striatal dopamine content and nigral dopamine neuron counts were relatively preserved compared to wild-type littermates. Further, microglia and astrocyte activation seen in wild-type mice challenged with MPTP was markedly attenuated in ASK⁻/⁻ mice. These data suggest that ASK1 is a key player in MPTP-induced glial activation linking oxidative stress with neuroinflammation, two well recognized pathogenetic factors in PD. These findings demonstrate that ASK1 is an important effector of MPTP-induced toxicity and suggest that inhibiting this kinase is a plausible therapeutic strategy for protecting dopamine neurons in PD.

[Decreased myocardial uptake of meta-iodobenzylguanidine in an autopsy-confirmed case of corticobasal degeneration with Lewy bodies restricted to the sympathetic ganglia]

We report on an autopsy case of corticobasal degeneration (CBD) with Lewy bodies in only the sympathetic ganglia. A 79-year-old man showed walking disturbance as an initial symptom, and developed dementia and bradykinesia within the next 2 years. Neurological examination revealed parkinsonism-like akinesia and rigidity in the trunk and neck without resting tremor. Brain magnetic resonance imaging showed frontal lobe atrophy predominantly on the right side. Cardiac uptake of meta-iodobenzylguanidine (MIBG) was reduced (H/M ratio: 1.14). A diagnosis of dementia with Lewy bodies (DLB) was made, but L-dopa treatment was not effective. Seven years later he died of pneumonia. On pathological examination, the frontal cortex and white matter were degenerated, predominantly on the right side. Gallyas-Braak silver staining and AT-8 immunostaining revealed neurofibrillary tangles, pretangles, argyrophilic threads, and astrocytic plaques in the cerebral cortex and basal ganglia, confirming the diagnosis of CBD. Lewy bodies, which were not seen in the central nervous system, were seen only in the sympathetic ganglia, and a severe loss of nerve fibers was apparent in the sympathetic nerve endings in the heart. MIBG is currently used to differentiate DLB from other parkinsonisms, such as CBD, multiple system atrophy, and progressive supranuclear palsy, because reduced cardiac uptake of MIBG represents a pathological change in the sympathetic nerve endings in the heart. However, the distribution of Lewy bodies cannot be determined from this finding. Thus, MIBG should not be used alone to confirm a diagnosis of DLB; other neurodegenerative diseases with incidental Lewy body disease, as in the present case, must be also considered.

The characteristics of the mechanoreceptors of the hip with arthrosis

Mechanoreceptors have been extensively studied in different joints and distinct signals that convey proprioceptive information to the cortex. Several clinical reports have established a link between the number of mechanoreceptors and a deficient proprioceptive system; however, little or no literature suggest concentration of mechanoreceptors might be affected by hip arthrosis. The purpose of this study is first to determine the existence of mechanoreceptors and free nerve endings in the hip joint and to distinguish between their conditions: those with arthrosis and without arthrosis. Samples of 45 male hips were analyzed: 30 taken from patients with arthrosis that were submitted to total arthroplasty and 15 taken from male cadavers without arthrosis. The patients' ages ranged from 38 to75 years (average 56.5) and the cadavers' ages ranged from 21 to 50 years (average 35.5). The capsule, labrum, and femoral head ligament tissues were obtained during the arthroplasty procedure from 30 patients with arthrosis and from 15 male cadavers. The tissue was cut into fragments of around 3 mm. Each fragment was then immediately stained with gold chloride 1% solution and divided into sections of 6 μm thickness. The Mann-Whitney test was used for two groups and the ANOVA, Friedman and Kruskal-Wallis tests for more than two groups. Results show the mechanoreceptors (Pacini, Ruffini and Golgi corpuscles) and free nerve endings are present in the capsule, femoral head ligament, and labrum of the hip joint. When all the densities of the nerve endings were examined with regard to those with arthrosis and those without arthrosis, the mechanoreceptors of cadavers without arthrosis were found to be more pronounced and an increase in free nerve endings could be observed (p = 0.0082). Further studies, especially electrophysiological studies, need to be carried out to clarify the functions of the mechanoreceptors in the joints.

SMN requirement for synaptic vesicle, active zone and microtubule postnatal organization in motor nerve terminals

Low levels of the Survival Motor Neuron (SMN) protein produce Spinal Muscular Atrophy (SMA), a severe monogenetic disease in infants characterized by muscle weakness and impaired synaptic transmission. We report here severe structural and functional alterations in the organization of the organelles and the cytoskeleton of motor nerve terminals in a mouse model of SMA. The decrease in SMN levels resulted in the clustering of synaptic vesicles (SVs) and Active Zones (AZs), reduction in the size of the readily releasable pool (RRP), and the recycling pool (RP) of synaptic vesicles, a decrease in active mitochondria and limiting of neurofilament and microtubule maturation. We propose that SMN is essential for the normal postnatal maturation of motor nerve terminals and that SMN deficiency disrupts the presynaptic organization leading to neurodegeneration.

Increased expression of tyrosine hydroxylase and anomalous neurites in catecholaminergic neurons of ATF-2 null mice

ATF-2/CRE-BP1 was originally identified as a cAMP-responsive element (CRE) binding protein abundant in the brain. We previously reported that phosphorylation of ATF-2 increased the expression of tyrosine hydroxylase (TH), which is the rate-limiting enzyme for catecholamine biosynthesis, directly acting on the CRE in the promoter region of the TH gene in PC12D cells (Suzuki et al. [2002] J. Biol. Chem. 277:40768-40774). To examine the role of ATF-2 on transcriptional control of the TH gene in the brain, we investigated the TH expression in ATF-2-/- mice. We found that TH expression was greatly increased in medulla oblongata and locus ceruleus of the ATF-2-deficient embryos. Ectopic expression of TH was observed in the raphe magnus nucleus, where serotonergic neural cell bodies are located. Interestingly, A10 dorsal neurons were lost in the embryos of ATF-2-/- mice. There was no difference in the TH immunoreactivity in the olfactory bulb. The data showed that alteration in TH expression by absence of ATF-2 gradually declined from caudal to rostral part of the brain. We also found anomalous neurite extension in catecholaminergic neurons of ATF-2 null mice, i.e., increased dendritic arborization and shortened axons. These data suggest that ATF-2 plays critical roles for proper expression of the TH gene and for neurite extension of catecholaminergic neurons, possibly through a repressor-like action.

Mid-term results of stapled hemorrhoidopexy for third- and fourth-degree hemorrhoids--correlation with the histological features of the resected tissue

BACKGROUND

Stapled hemorrhoidopexy is used to remove a circumferential strip of mucosa and submucosa about 4 cm above the dentate line, in order to restore the correct anatomical relationships of the anal canal structures. We evaluated the histological features of the resected tissue obtained after stapled hemorrhoidopexy with correlation to the short-term and mid-term results.

METHODS

This retrospective study evaluated 234 cases of stapled hemorrhoidopexy. Data concerning postoperative bleeding, anal pain, incontinence, stenosis, and recurrence of hemorrhoids were collected from hospital and outpatient clinic records. Histologic slides were examined for the type of epithelium, presence of muscle fibers, nerve endings, and degree of vascular ectasia.

RESULTS

Some 52% of the biopsies revealed on the surface a combination of glandular with squamous epithelium, meaning a stapling line at the level of the transitional zone/dentate line. Smooth muscle fibers were more frequent as the stapling line approached the level of the dentate line/transitional zone (p = 0.0028). Internal sphincter fibers were present in 36% of the cases, yet there were no cases of anal incontinence. Inclusion of merely squamous epithelium in the resected tissue correlated with severe postoperative pain persisting one week after surgery (p < 0.0001), whereas the concurrent presence of squamous and glandular epithelium correlated only with severe pain on the first postoperative day (p = 0.018). Nerve endings were more frequent in patients with anal pain one week after surgery (p = 0.02). The rate of recurrence of symptoms was 3%, which did not correlate with any of the histological parameters tested.

CONCLUSIONS

Though stapled hemorrhoidopexy is performed according to well-established technical guidelines, it is too difficult to be standardized.

Free nerve endings and morphological features of the ligamentum capitis femoris in developmental dysplasia of the hip

A conflict exists on whether the ligamentum capitis femoris has the neuro-morphological structures required for nociception or proprioception of the hip joint. Therefore, we investigated the morphological features and the presence of mechanoreceptors in 24 ligamentum capitis femoris biopsies obtained at open reduction in patients with developmental dysplasia of the hip. Of these 24 hips, 16 were completely dislocated and eight were subluxated. The mean age was 33.8 months (range 13-52 months) at the time of surgery. En bloc ligamentum capitis femoris and pulvinar were taken for biopsy specimen. Ligamentum capitis femoris was dissected and the weight of each ligament was determined using a highly sensitive balance. Specimens were stained with hematoxylin and eosin and Masson trichrome for routine histolopathological evaluation and examined immunohistochemically using monoclonal antibody against S-100 protein. All specimens were graded on a four-grade system according to the amount of coarse-thick collagen bundles and hyalinization. The mean number and type of mechanoreceptors of each specimen were recorded. When the mean age, the patient's weight and the ligamentum capitis femoris weight of each group (completely dislocated vs. subluxated) were compared, there were no significant differences. In the ligamentum capitis femoris of the dislocated hips, the cells were irregularly distributed, had different shapes, and appeared to be in different stages of functional activity. The collagen fiber bundles were thicker than in the subluxated hips, distributed and of varied thickness. The elastic fibers of the dislocated hips were thicker and more numerous than those in the subluxated hips. We found a significant difference between the two groups with regard to the grade of collagen and hyalinization of ligamentum capitis femoris (P<0.004). We found type IVa, free nerve endings in 16 of 24 samples of ligamentum capitis femoris. The 66.6% presence of free nerve endings in the ligamentum capitis femoris suggests a role in nociception/proprioception of the hip in developmental dysplasia of the hip. Interestingly, the percentage and the mean numbers of free nerve endings containing ligamentum capitis femoris were similar in completely dislocated hip group and the subluxated group (62.5 vs. 75%, 12.13+/-9.07 vs. 9.37+/-9.24, respectively). We conclude that the morphological features of ligamentum capitis femoris are influenced by the severity of developmental dysplasia of the hip, whereas the distribution of free nerve endings are not influenced.

Deletion of μ- and κ-Opioid Receptors in Mice Changes Epidermal Hypertrophy, Density of Peripheral Nerve Endings, and Itch Behavior

The mu- (MOR) and kappa- (KOR) opioid receptors have been implicated in the regulation of homeostasis of non-neuronal cells, such as keratinocytes, and sensations like pain and chronic pruritus. Therefore, we have studied the phenotype of skin after deletion of MOR and KOR. In addition, we applied a dry skin model in these knockout mice and compared the different mice before and after induction of the dermatitis in terms of epidermal thickness, epidermal peripheral nerve ending distribution, dermal inflammatory infiltrate (mast cells, CD4 positive lymphocytes), and scratching behavior. MOR knockout mice reveal as phenotype a significantly thinner epidermis and a higher density of epidermal fiber staining by protein gene product 9.5 than the wild-type counterparts. Epidermal hypertrophy, induced by the dry skin dermatitis, was significantly less developed in MOR knockout than in wild-type mice. Neither mast cells nor CD4 T(h)-lymphocytes are involved in the changes of epidermal nerve endings and epidermal homeostasis. Finally, behavior experiments revealed that MOR and KOR knockout mice scratch less after induction of dry skin dermatitis than wild-type mice. These results indicate that MOR and KOR are important in skin homeostasis, epidermal nerve fiber regulation, and pathophysiology of itching.

[Analysis of enteral nervous system in children with drug resistant ulcerative colitis]

INTRODUCTION

pathogenesis of inflammatory bowel diseases has been intensively investigated for many years. The role of enteric nervous system (ENS) and neuroprotective transmitters such as galanine (GAL), vasoactive intestinal peptide (VIP) and pituitary adenosine cyclase activating peptide (PACAP) has been underlined recently. Neuroprotective transmitters play a role in the regulation of intestinal contractions, ion transport in the intestinal epithelium and modulation of the proinflammatory cytokine production, which may result in diminuation of inflammation.

AIM OF THE STUDY

was to investigate activity of ENS in children with drug resistant ulcerative colitis measured by the density of GAL, VIP and/or PACAP containing nervous fibres in mucosal membrane in course of pharmacological treatment and 12 months after colectomy.

MATERIAL AND METHODS

16 children were included in the study. Group I consisted of 7 children with drug resistant ulcerative colitis. Mucosal biopsy specimen was taken twice: colonoscopy before colectomy during (12 months earlier on average) and from resected colon. Group II (reference group) consisted of 9 children with excluded inflammatory bowel diseases based on colonoscopy and biopsy mucosal specimen assessment. Histology and immunochemistry of mucosal samples were analysed.

RESULTS

decreased density of GAL, VIP and/or PACAP containing nervous fibres in colon mucosal membrane of children with ulcerative colitis was found: GAL-IR (3.5 +/- 3.15), VIP-IR (19.7 +/- 2.7), PACAP-IR (6.3+/-2.52) as compared to the reference group: GAL-IR (11.2+/-5.58), VIP-IR (36.1 +/- 16.0) and PACAP-IR (15.7 +/- 9.95). Significant diminuation of the density of GAL, VIP and/or PACAP containing nervous fibres was found in the study.

CONCLUSION

1. The density of VIP, PACAP and GAL containing nerve fibres diminishes in the course of ulcerative colitis, which may be a result of progressive degradation of colon mucosal membrane. 2. The hypothesis that absence of chemotaxis inhibition by low levels of neuroprotective transmitters might be a reason for drug resistance in ulcerative colitis.

Virus-specific CD8+ T cells accumulate near sensory nerve endings in genital skin during subclinical HSV-2 reactivation

Cytotoxic CD8⁺ T cells play a critical role in controlling herpes simplex virus (HSV) infection and reactivation. However, little is known about the spatiotemporal dynamics of CD8⁺ T cells during HSV lesion evolution or about their involvement in immune surveillance after lesion resolution. Using quantum dot–conjugated peptide–major histocompatibility complex multimers, we investigated the in vivo localization of HSV-2–specific CD8⁺ T cells in sequential biopsies of human genital skin during acute, resolving, and healed stages of HSV-2 reactivation. Our studies revealed that functionally active CD8⁺ T cells selectively infiltrated to the site of viral reactivation. After lesion healing in concert with complete reepithelialization and loss of HSV DNA from skin biopsies, HSV-2–specific CD8⁺ T cells persisted for more than two months at the dermal–epidermal junction, adjacent to peripheral nerve endings. In two out of the six sequentially studied individuals, HSV-2 DNA reappeared in clinically and histologically normal–appearing skin. Detection of viral DNA was accompanied by increased numbers of both HSV-specific and total CD8⁺ T cells in the dermis. These findings indicate that the frequency and clinical course of HSV-2 reactivation in humans is influenced by virus-specific CD8⁺ T cells that persist in peripheral mucosa and genital skin after resolution of herpes lesions.

Defining a Treatable Cause of Erythromelalgia: Acute Adolescent Autoimmune Small-Fiber Axonopathy

Conditions described as "erythromelalgia" and "erythermalgia" are being formally specified by etiological diagnoses that enable the use of disease-modifying as well as symptomatic treatments. We describe an otherwise healthy 20-year-old man with acute-onset erythromelalgia. Severe bilateral distal limb pain and vasodilation persisted despite the use of many antihyperalgesics. Pathological examination of cutaneous nerve endings revealed severe small-fiber predominant axonopathy. Treatment of his apparent autoimmune polyneuropathy with high dose corticosteroids, 4 days of lidocaine infusion, and a prednisone taper cured him. Similarities to other cases allowed us to tentatively characterize a new treatable cause of erythromelalgia; acute adolescent autoimmune small-fiber axonopathy. In this report we evaluate various options for diagnosis and treatment.

Dopamine quinones activate microglia and induce a neurotoxic gene expression profile: relationship to methamphetamine-induced nerve ending damage

Methamphetamine (METH) intoxication leads to persistent damage of dopamine (DA) nerve endings of the striatum. Recently, we and others have suggested that the neurotoxicity associated with METH is mediated by extensive microglial activation. DA itself has been shown to play an obligatory role in METH neurotoxicity, possibly through the formation of quinone species. We show presently that DA-quinones (DAQ) cause a time-dependent activation of cultured microglial cells. Microarray analysis of the effects of DAQ on microglial gene expression revealed that 101 genes were significantly changed in expression, with 73 genes increasing and 28 genes decreasing in expression. Among those genes differentially regulated by DAQ were those often associated with neurotoxic conditions including inflammation, cytokines, chemokines, and prostaglandins. In addition, microglial genes associated with a neuronally protective phenotype were among those that were downregulated by DAQ. These results implicate DAQ as one species that could cause early activation of microglial cells in METH intoxication, manifested as an alteration in the expression of a broad biomarker panel of genes. These results also link oxidative stress, chemical alterations in DA to its quinone, and microglial activation as part of a cascade of glial-neuronal crosstalk that can amplify METH-induced neurotoxicity.

The Role of Neuron Numbers of the Petrosal Ganglion in the Determination of Blood Pressure: An Experimental Study

BACKGROUND

Baroreceptor reflexes are regulated by nerve terminals of the glossopharyngeal and vagal nerves. The body of pressure-sensitive neurons of these nerves is located in the petrosal ganglion of both nerves. We examined whether there is a relationship between the neuron numbers of the inferior ganglion of the glossopharyngeal nerve and blood pressure values.

METHODS

Petrosal ganglions were examined in 18 male hybrid rabbits divided into three equal groups: Group A normotensive (TA=90-100 mmHg), Group B hypertensive (TA>100 mmHg); and Group C hypotensive (TA<90 mmHg). After examination of blood pressure for one week, all animals were sacrificed, and the petrosal ganglions extracted bilaterally and examined histopathologically using the physical dissector method.

RESULTS

The mean (+/-SD) neuronal density was: Group A 8700+/-200, Group B 7800+/-250 and Group C 9800+/-300, respectively. The difference between the groups B and C as compared to A was significant (p<0.01) while the difference between Groups B and C was highly significant (p<0.001).

CONCLUSIONS

An inverse relationship was noticed between the neuronal density in the petrosal ganglion and blood pressure values with potential implications in the study of the etiology of hypertension.

Cardiac NGF and GDNF expression during Trypanosoma cruzi infection in rats

In rats, autonomic nerve endings are damaged during Trypanosoma cruzi-induced myocarditis. Gradual recovery occurs after the acute phase. The present work shows the cardiac levels of glial cell line-derived neurotrophic factor (GDNF) and nerve growth factor (NGF), and their cellular sources during T. cruzi infection in rats. Atrial and ventricular NGF levels (ELISA) increased significantly at day 20 post inoculation, the time-point of maximal sympathetic denervation. ELISA failed to show significant increase of cardiac GDNF levels. However immunohistochemistry showed a significant increase of anti-GDNF gold particles over atrial granules at day 20. Light microscopy showed stronger NGF immunostaining in atrial cardiomyocytes and several blood capillaries. In situ hybridization showed NGF and GDNF mRNAs in atrial and ventricular myocytes of both infected and uninfected animals. Endothelial cells exhibited NGF mRNA and protein only in infected rats. No evidence of neurotrophic factor expression by the infiltrating mononuclear cells was found. This is the first report on neurotrophic factor expression during T. cruzi infection. Our findings indicate an important role for NGF in the regenerative phenomena subsequent to a myocarditis able to damage sympathetic nerve endings, with preservation of preterminals and nerve trunks. GDNF could have a minor or a more transient participation.

Preserved norepinephrine reuptake but reduced sympathetic nerve endings in hypertrophic volume-overloaded rat hearts

BACKGROUND

In congestive heart failure (CHF), an activation of the cardiac sympathetic nervous system results in depleted cardiac norepinephrine (NE) stores. The underlying regulatory mechanisms are discussed controversially and were investigated in the present study in CHF resulting from volume overload.

METHODS AND RESULTS

Aorto-caval shunt (AVS) was performed in rats. Plasma NE levels were determined by radioenzymatic assay, left ventricular NE by high-performance liquid chromatography, endothelin-1 by enzyme-linked immunosorbent assay. Tyrosine-hydroxylase (TH)- and nerve growth factor (NGF)-mRNA was determined by Northern blot analysis and ribonuclease-assay. Cardiac [3H]-NE uptake was measured in isolated perfused hearts. Glyoxylic acid-induced histofluorescence was used to quantify cardiac sympathetic nerves. Compared with sham-operated animals (SH), AVS rats were characterized by depleted cardiac NE stores and enhanced NE plasma levels. Neither TH-mRNA levels in stellate ganglia, nor cardiac [3H]-NE-uptake were reduced in AVS. The left ventricular density of sympathetic nerves was markedly decreased. Gene expression of myocardial NGF (a positive regulator of NE reuptake and cardiac sympathetic nerve density) and left ventricular endothelin-1 (a negative regulator of NE reuptake and positive regulator of cardiac NGF expression) were unchanged.

CONCLUSION

In volume-overloaded hypertrophic hearts, depletion of cardiac NE stores is caused by a reduction of the sympathetic nerve density, whereas cardiac NE reuptake is preserved.

Ongoing epileptiform activity in the post-ischemic hippocampus is associated with a permanent shift of the excitatory-inhibitory synaptic balance in CA3 pyramidal neurons

Ischemic strokes are often associated with late-onset epilepsy, but the underlying mechanisms are poorly understood. In the hippocampus, which is one of the regions most sensitive to ischemic challenge, global ischemia induces a complete loss of CA1 pyramidal neurons, whereas the resistant CA3 pyramidal neurons display a long-term hyperexcitability several months after the insult. The mechanisms of this long-term hyperexcitability remain unknown despite its clinical implication. Using chronic in vivo EEG recordings and in vitro field recordings in slices, we now report spontaneous interictal epileptiform discharges in the CA3 area of the hippocampus from post-ischemic rats several months after the insult. Whole-cell recordings from CA3 pyramidal neurons, revealed a permanent reduction in the frequency of spontaneous and miniature GABAergic IPSCs and a parallel increase in the frequency of spontaneous and miniature glutamatergic postsynaptic currents. Global ischemia also induced a dramatic loss of GABAergic interneurons and terminals together with an increase in glutamatergic terminals in the CA3 area of the hippocampus. Altogether, our results show a morpho-functional reorganization in the CA3 network several months after global ischemia, resulting in a net shift in the excitatory-inhibitory balance toward excitation that may constitute a substrate for the generation of epileptiform discharges in the post-ischemic hippocampus.

Pulmonary neuroendocrine cells, airway innervation, and smooth muscle are altered in Cftr null mice

The amine- and peptide-producing pulmonary neuroendocrine cells (PNEC) are widely distributed within the airway mucosa of mammalian lung as solitary cells and innervated clusters, neuroepithelial bodies (NEB), which function as airway O2 sensors. These cells express Cftr and hence could play a role in the pathophysiology of cystic fibrosis (CF) lung disease. We performed confocal microscopy and morphometric analysis on lung sections from Cftr-/- (null), Cftr+/+, and Cftr+/- (control) mice at developmental stages E20, P5, P9, and P30 to determine the distribution, frequency, and innervation of PNEC/NEB, innervation and cell mass of airway smooth muscle, and neuromuscular junctions using synaptic vesicle protein 2, smooth muscle actin, and synaptophysin markers, respectively. The mean number of PNEC/NEB in Cftr-/- mice was significantly reduced compared with control mice at E20, whereas comparable or increased numbers were observed postnatally. NEB cells in Cftr null mice showed a significant reduction in intracorpuscular nerve endings compared with control mice, which is consistent with an intrinsic abnormality of the PNEC system. The airways of Cftr-/- mice showed reduced density (approximately 20-30%) of smooth muscle innervation, decreased mean airway smooth muscle mass (approximately 35%), and reduced density (approximately 20%) of nerve endings compared with control mice. We conclude that the airways of Cftr-/- mice exhibit heretofore unappreciated structural alterations affecting cellular and neural components of the PNEC system and airway smooth muscle and its innervation resulting in blunted O2 sensing and reduced airway tonus. Cftr could play a role in the development of the PNEC system, lung innervation, and airway smooth muscle.

[Changes in the number of neuroprotective transmitter containing mucosal nerve fibres in children with ulcerative colitis]

INTRODUCTION

Ulcerative colitis and Crohn's disease are two main disease entities that belong to the group of inflammatory bowel diseases (IBD). Chronic inflammatory process concerning intestinal mucosal membrane causes structural and functional changes of intestinal nervous system. This phenomenon is called the plasticity of the nervous system and is due to the ability of nerve cells to adapt to changing environmental conditions. The resulting alterations of intestinal neurons' chemical code are augmentation, inhibition or initiation of the neurotransmitters' synthesis (synthesis "de novo"). The role of neuroprotective transmitters - galanine (GAL), vasoactive intestinal peptide (VIP) and pituitary adenosine cyclase activating peptide (PACAP) seems to be important in the pathogenesis of inflammatory bowel diseases. They are responsible for the regulation of intestinal contraction and modification of ions' transport in the intestinal epithelium. They also diminuate the inflammation by modulation of the proinflammatory chemokines and cytokines production.

THE AIM

of the study was to analyse the changes in the nerve fibres' containing GAL, VIP and/or PACAP, density in the mucosal membrane of children with ulcerative colitis (UC) with different Clinical activity index.

MATERIAL AND METHODS

the study included 33 children hospitalised due to UC with different activity and 9 children in the control group, after exclusion of IBD. All the studied patients underwent colonoscopic examination with colon mucosa biopsies. Histology and immunochemistry of mucosal samples were analysed. Those studies helped to assess the changes in the number of nerve fibres containing analysed transmitter substances in the mucosal membrane of the colon.

RESULTS

the results showed a statistically significant diminuation of nerve fibres containing analysed neurotransmitters number in colon mucosa samples of children with UC. There were no statistically significant changes in number of nerve fibres dependent on the clinical activity index of UC.

CONCLUSIONS

the process of degradation present in UC is accompanied by the important diminuation on neurotransmitter containing fibres number. However, their density is not dependent of the clinical activity of the disease.

Second application of low-energy shock waves has a cumulative effect on free nerve endings

Some physicians recommend treating tendinopathies with multiple sessions of shock waves. Some evidence, however, suggests shock wave application can induce nerve fiber degeneration. We questioned whether repeated shock wave application provides a cumulative effect on nerve fibers compared with the effect of one application. One thousand shock wave impulses of an energy flux density of 0.08 mJ/mm were applied to the foot pad of 32 rats. After 14 days, 16 rats received a second application. The foot pads were resected on Days 7, 14, 28, and 42. Sections were processed immunohistochemically using antibodies for sensory nerve. We compared the number of epidermal nerve fibers in rats that received one application of shock waves with the fibers in rats that received two applications. During the first 4 weeks, there was nearly complete degeneration of epidermal nerve fibers in both groups. By the end of 6 weeks, reinnervation of the epidermis began in the single-treatment group. Reinnervation occurred slower in the repeated-treatment group. These data show that a second application has a cumulative effect on nerve fibers. Our data suggest multiple applications of low-energy shock waves might a provide longer-lasting antinociceptive effect.