Adrenomedullin 2/Intermedin in the Hypothalamo–Pituitary–Adrenal Axis

Adrenomedullin 2/intermedin (AM2/IMD) is a new member of the calcitonin/calcitonin gene-related peptide (CGRP) family. CGRP, adrenomedullin (AM), and AM2/IMD share the receptor system consisting of calcitonin receptor-like receptor (CRLR) and receptor activity-modifying proteins (RAMP). The CRLR/RAMP2 or CRLR/RAMP3 complex forms the AM receptor, whereas the CRLR/RAMP1 forms the CGRP receptor. AM2/IMD binds non-selectively to all three CRLR/RAMP complexes. AM2/IMD has various actions, such as a potent vasodilator action and a protective action against oxidative stress, like AM and CGRP. When administered intracerebroventricularly, AM2/IMD stimulates the sympathetic nervous system and increases blood pressure. In human hypothalamus, AM2/IMD is expressed in the paraventricular and supraoptic nuclei and colocalized with arginine vasopressin. Anterior pituitary cells were diffusely immunostained for AM2/IMD. AM2/IMD stimulates the release of ACTH, prolactin, and oxytocin, but suppresses GH release. Some of these pituitary actions of AM2/IMD have been supposed to be mediated by an unidentified unique receptor for AM2/IMD. In the adrenal gland, immunoreactive (IR)-AM2/IMD and IR-AM were detected in the medulla, while the degree of IR-AM2/IMD and IR-AM in the cortex was relatively weak or undetectable. Furthermore, AM2/IMD and AM were expressed in adrenocortical tumors, such as aldosterone-secreting adenomas, and pheochromocytomas. CRLR and RAMPs are expressed in the hypothalamus, pituitaries, adrenal glands, and adrenal tumors. Thus, AM2/IMD is expressed in every endocrine organ of the hypothalamo–pituitary–adrenal axis together with its receptor. AM2/IMD may act as a neurotransmitter or modulator in the brain and as a paracrine/autocrine regulator in the hypothalamo–pituitary–adrenal axis.     

SARS-CoV-2–associated Guillain–Barre syndrome requires extensive pre- and post-mortem examinations

Journal of NeuroVirology -     

Vincristine exacerbates asymptomatic Charcot–Marie–Tooth disease with a novel EGR2 mutation

Neurotoxicity is a common side effect of vincristine (VCR) treatment. Severe exacerbations of neuropathy have been reported in patients with Charcot–Marie–Tooth disease (CMT) 1A with duplication of the peripheral myelin protein 22 (PMP22) gene. However, whether or not VCR exacerbates neuropathies through mutations in other CMT-associated genes besides PMP22 duplication has not been well studied. The purpose of this study was to identify mutations in any CMT-associated genes in a patient with hypersensitivity to VCR. We performed clinical, electrophysiological, and genetic examinations of a 23-year-old woman, who was hypersensitive to low-dose VCR, and her healthy mother. DNA analysis was performed using our specially designed resequencing array that simultaneously screens for 28 CMT-associated genes. Electrophysiological studies revealed that the patient and her healthy mother had demyelinating polyneuropathy. Furthermore, they showed the same novel mutation in the early growth response 2 (EGR2) gene. Recognizing pre-existing asymptomatic CMT by electrophysiological studies and genetic analysis before VCR treatment allowed us to prevent severe VCR-induced neuropathy.     

Adenine nucleotide translocase is involved in a mitochondrial coupling defect in MFN2-related Charcot–Marie–Tooth type 2A disease

Charcot–Marie–Tooth type 2A disease (CMT2A), a dominantly inherited peripheral neuropathy, is caused by mutations in MFN2, a mitochondrial fusion protein. Having previously demonstrated a mitochondrial coupling defect in CMT2A patients’ fibroblasts, we here investigate mitochondrial oxygen consumption and the expression of adenine nucleotide translocase (ANT) and uncoupling proteins from eight other patients with the disease. The mitochondrial uncoupling was associated with a higher respiratory rate, essentially involving complex II proteins. Furthermore, a twofold increase in the expression of ANT led to the reduced efficiency of oxidative phosphorylation in CMT2A cells, suggesting that MFN2 plays a role in controlling ATP/ADP exchanges.     

5HT–2C receptor polymorphism in suicide victims

Abstract. Sustainable observations suggest that suicidal behaviour by itself may have biological correlates, among which those related to the serotonergic synapse hold the key position. Based on the association of suicide and serotonergic dysfunction, it was proposed that genetic mechanisms affecting suicidal behaviour could be related to the alterations of the genes encoding the elements of 5HT synapse. The present study tested the association of the polymorphism in the serotonin 2C (5HT-2C) receptor coding region (Cys23Ser) with suicide commitment. Study was based on two independent samples, one of German (284 suicide victims versus 297 controls) and other of Slavic/Croatian (118 suicide victims versus 275 controls) ethnicity. No significant differences in allele or genotype frequencies between victims and controls were demonstrated. Results did not provide supporting evidence for the potential involvement of the investigated variants of 5HT-2C receptor in the susceptibility to suicide.     

Rigid variety occiput/C1–C2–C3 internal fixation in pediatric population

Purpose

The purpose of this study was to review our experience of rigid internal fixation of craniovertebral junction in pediatric population. A new technique of reduction of basilar invagination with atlantoaxial dislocation is described. To the best of our knowledge and available scientific literature, this technique has not yet been described in younger patients.

Methods

We have managed 27 children by rigid variety of occiput/C1–C2–C3 internal fixation of various craniovertebral junction pathologies. All patients were subjected to thin cuts of computed tomography with 3D reconstruction for selecting appropriate rigid construct. Eight children had occiput-C2, 3 had occiput-C2–C3, and 16 had C1-C2 hardware constuct. One patient of C1–C2-plate fixation had section of C2 nerve root ganglia. Basilar invagination with atlantoaxial dislocation was reduced by new distraction/compression techniques.

Results

Improvement in clinical features and correction of deformity with solid hardware construct were seen in all patients. Follow-up period ranged from 5–72 months. One patient was lost to follow-up, and one case died of compression of vertebral artery at C1 lateral mass. Patients of myelopathy had recovery rate of 90.9 %. Hardware failure was seen in one patient, and wound infection was observed in two cases.

Conclusions

Rigid variety of occiput/C1–C2 internal fixation is a safe and effective method in the management of variety of craniovertebral pathologies in pediatric population. This new technique of reduction of basilar invagination with atlantoaxilal dislocation from posterior approach may alleviate the need of high morbity associated with surgical procedure like transoral odontoidectomy in younger patients.     

Glatiramer acetate induces pro–apoptotic mechanisms involving Bcl–2, Bax and Cyt–c in peripheral lymphocytes from multiple sclerosis patients

Apoptotic deletion of autoreactive T-cells is defective in patients with multiple sclerosis (MS). Glatiramer acetate (GA) treatment seems to restore apoptosis of detrimental T-cells. We analyzed the mitochondria membrane pro- (Bax) and anti-apoptotic (Bcl- 2) and cytosolic pro-apoptotic (Cyt-c, APAF-1) proteins expression in peripheral lymphocytes from relapsing-remitting (RR) MS patients during GA treatment. Blood samples were collected from 8 healthy controls (HCs) and from 8 RR MS patients prior to and every three months during the 9 months of GA treatment. Peripheral blood mononuclear cells (PBMNCs) Bcl-2, Bax, Cyt-c and APAF-1 were quantified by western blot followed by densitometric scanning and Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios were calculated. T-cells were in vitro tested for oxygen consumption by a respirometric analysis. Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios in untreated MS patients were significantly (p < 0.05) lower than in HCs. Bax/Bcl-2 ratio increased (p = 0.03) and Cyt-c/Bcl-2 ratio showed a trend to increase during the 9 months of GA treatment in MS patients. A reduction of 58% and 59% in oxygen consumption by PBMNCs was evident after GA treatment in vitro or when GA treated patients' cells were compared with those from HCs, respectively. Our findings suggest that GA exerts a regulatory effect on peripheral T lymphocytes through pro-apoptosis mechanisms involving mitochondria and cytosolic proteins.     

The modulation of the excitability of primary sensory neurons by Ca2+–CaM–CaMKII pathway

Ca(2+)-calmodulin (CaM) dependent protein kinase II (CaMKII) is an important intracellular signal transduction pathway. CaMKII is rich in the primary sensory neurons and specifically presents in the small- and medium-sized neurons. It remains unclear about the modulation on the excitability of primary sensory neurons by Ca(2+)-CaM-CaMKII pathway. By current clamp recording, we found that the excitability of capsaicin-sensitive small and medium trigeminal ganglion (TG) neurons was significantly reduced by a CaM specific antagonist (W-7) and a CaMKII antagonist (KN-93). The inhibition is represented as the reduction of numbers of action potential (AP), decrease of the amplitude of AP, increase of threshold, and prolongation of duration of AP. Consistently, by voltage clamp recording, we found that both voltage-gated sodium channels (VGSCs) and voltage-gated potassium channels (VGPCs) were inhibited by W-7 and KN-93 in the order of total sodium (Na(+)) current (INa-T)?>?sustained potassium (K(+)) current (IK)?>?A-type K(+) current (IA). In addition, AIP (a selective CaMKII peptide inhibitor) and KN-93 caused a similar inhibition of INa-T and IK. Those evidences show that the excitability of capsaicin sensitive small and medium TG neurons can be regulated by Ca(2+)-CaM-CaMKII pathway through modulating VGSCs and VGPCs. Considering the specific distribution of CaMKII and its susceptibility to many analgesic stimuli, Ca(2+)-CaM-CaMKII pathway may play an important role in the peripheral sensory transduction, especially in nociception.     

Clinical effects of COX–2 inhibitors on cognition in schizophrenia

An activation of pro–inflammatory cytokines in the central nervous system is associated with cognitive disturbances. This process is mediated by prostaglandins and cyclo–oxygenase–2 (COX–2). COX–2 inhibitors have been suggested to show beneficial effects in disorders associated with cognitive disturbance, although clinical effects on cognition have not been shown until today. Data from a schizophrenia study were reevaluated under the aspect whether an effect on the positive and negative syndrome scale (PANSS) factor cognition can be observed during therapy with the COX–2 inhibitor celecoxib add on to risperidone in comparison to riperidone alone. Beside the effect on the PANSS total score, the effect on the cognition factor was the most pronounced using the analysis of covariance compared to all other factors of the PANSS (p <0.06). Although suggestions of basic research led to an expected therapeutic effect of COX–2 inhibitors on cognition, this effect could not yet be shown clinically. In schizophrenia, the effect on cognition contributes to the therapeutic effect of COX–2 inhibitors.     

T2–T4 sympathectomy versus T3–T4 sympathicotomy for palmar and axillary hyperhidrosis

Objective  

To evaluate and compare the immediate and long-term outcomes of videothoracoscopic T2–T4 sympathectomy and T3–T4 sympathicotomy for the treatment of palmar and axillary hyperhidrosis.     

The expression of angiotensin-converting enzyme 2–angiotensin-(1–7)–Mas receptor axis are upregulated after acute cerebral ischemic stroke in rats

There is now unequivocal evidence that the angiotensin-converting enzyme 2(ACE2)–Ang-(1–7)–Mas axis is a key component of the renin–angiotensin system (RAS) cascade, which is closely correlated with ischemic insult occurrence. Our previous studies demonstrated that the Ang-(1–7), was an active member of the brain RAS. However, the ACE2–Ang-(1–7)–Mas axis expression after cerebral ischemic injury are currently unclear. In the present study, we investigated the time course of ACE2–Ang-(1–7) and Mas receptor expression in the acute stage of cerebral ischemic stroke. The content of Ang-(1–7) in ischemic tissues and blood serum was measured by specific EIA kits. Real-time PCR and western blot were used to determine messenger RNA (mRNA) and protein levels of the ACE2 and Mas. The cerebral ischemic lesion resulted in a significant increase of regional cerebral and circulating Ang-(1–7) at 6–48 h compared with sham operation group following focal ischemic stroke (12 h: 7.276 ± 0.320 ng/ml vs. 2.466 ± 0.410 ng/ml, serum; 1.024 ± 0.056 ng/mg vs. 0.499 ± 0.032, brain) (P < 0.05). Both ACE2 and Mas expression were markedly enhanced compared to the control in the ischemic tissues (P < 0.05). Mas immunopositive neurons were also seen stronger expression in the ischemic cortex (19.167 ± 2.858 vs. 7.833 ± 2.483) (P < 0.05). The evidence collected in our present study will indicate that, ACE2–Ang-(1–7)–Mas axis are upregulated after acute ischemic stroke and would play a pivotal role in the regulation of acute neuron injury in ischemic cerebrovascular diseases.     

Silencing thioredoxin1 exacerbates damage of astrocytes exposed to OGD/R by aggravating apoptosis through the Actin–Ras2–cAMP–PKA pathway

Purpose of the study: Induction of endogenous antioxidants is one of the key molecular mechanisms of cell resistance to hypoxia/ischemia. Thioredoxin1 (Trx1) is a small multifunctional ubiquitous antioxidant with redox-active dithiol and plays an important role in cell apoptosis through mitochondrial apoptosis pathways. The specific role of Trx1 in ischemia-reperfusion induced astrocyte apoptosis, however, remains unclear.

Materials and methods: In this study, we investigated the effect of Trx1 on apoptosis of astrocyte using an in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) model which mimics ischemic/reperfusion conditions in vivo. The astrocytes prepared from newborn Sprague-Dawley rats were exposed to OGD for 4 h followed by reoxygenation for 24 h. Next, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to assess cell viability while cell damage was assessed by lactate dehydrogenase (LDH).

Results: We found that OGD/R increased cell death as well as the expression of Trx1 and that the interference of Trx1 further aggravated astrocyte damage under OGD/R condition. Furthermore, we detected an increase in the intracellular expressions of Ras2, cAMP, and PKA under OGD/R condition, which paralleled cell injury.

Conclusions: Notably, the deletion of Trx1 exacerbated astrocyte apoptosis via the Ras2-cAMP-PKA signaling pathway. We concluded that Trx1 protects astrocytes against apoptotic injury induced by OGD/R, and this protective effect may be partly related to the Ras2-cAMP-PKA signaling pathway.     

The α2C-adrenoceptor deletion322–325 variant and cold-induced vasoconstriction

Objectives  Cold-induced vasoconstriction is mediated in part by selective enhancement of local α_2C-adrenoceptor (α_2C-AR) activity. A common insertion–deletion variant in the α_2C-AR gene (ADRA2C del322–325) results in an approximately 85% reduction of agonist-mediated function in vitro. We tested the hypothesis that individuals with the ADRA2C del322–325 variant have attenuated vasoconstriction in response to cold. Methods  Cutaneous digital blood flow (flux) was measured by laser Doppler flowmetry in a controlled environment at room temperature and during two cycles of graduated local heat and cold exposure in 31 subjects. Temperature–response curves were analyzed to estimate the following measures: E _min (minimal flux during cooling), and ET₅₀ and ET₉₀ (the local temperature at which flux decreased by 50 and 90%, respectively). Results  We found no significant genotypic differences in E _min (24.3 ± 19.5, 30.0 ± 20.5, and 21.5 ± 25.9 AU for ins/ins, ins/del, and del/del genotypes, respectively; P = 0.48), ET₅₀ (25.5 ± 6.0, 25.1 ± 6.7, and 25.1 ± 7.1°C; P = 0.99), or ET₉₀ (20.5 ± 4.7, 22.1 ± 4.0, and 20.8 ± 6.7°C; P = 0.77) in either the first or second heating and cooling cycle (cycle 1 values presented). Interpretation  The ADRA2C del322–325 variant did not affect vascular sensitivity to local cold exposure.     

Dynamic expression of Slit1–3 and Robo1–2 in the mouse peripheral nervous system after injury

The Slit family of axon guidance cues act as repulsive molecules for precise axon pathfinding and neuronal migration during nervous system development through interactions with specific Robo receptors.Although we previously reported that Slit1–3 and their receptors Robo1 and Robo2 are highly expressed in the adult mouse peripheral nervous system,how this expression changes after injury has not been well studied.Herein,we constructed a peripheral nerve injury mouse model by transecting the right sciatic nerve.At 14 days after injury,quantitative real-time polymerase chain reaction was used to detect mRNA expression of Slit1–3 and Robo1–2 in L4–5 spinal cord and dorsal root ganglia,as well as the sciatic nerve.Immunohistochemical analysis was performed to examine Slit1–3,Robo1–2,neurofilament heavy chain,F4/80,and vimentin in L4–5 spinal cord,L4 dorsal root ganglia,and the sciatic nerve.Co-expression of Slit1–3 and Robo1–2 in L4 dorsal root ganglia was detected by in situ hybridization.In addition,Slit1–3 and Robo1–2 protein expression in L4–5 spinal cord,L4 dorsal root ganglia,and sciatic nerve were detected by western blot assay.The results showed no significant changes of Slit1–3 or Robo1–2 mRNA expression in the spinal cord within 14 days after injury.In the dorsal root ganglion,Slit1–3 and Robo1–2 mRNA expression were initially downregulated within 4 days after injury;however,Robo1–2 mRNA expression returned to the control level,while Slit1–3 mRNA expression remained upregulated during regeneration from 4–14 days after injury.In the sciatic nerve,Slit1–3 and their receptors Robo1–2 were all expressed in the proximal nerve stump;however,Slit1,Slit2,and Robo2 were barely detectable in the nerve bridge and distal nerve stump within 14 days after injury.Slit3 was highly ex-pressed in macrophages surrounding the nerve bridge and slightly downregulated in the distal nerve stump within 14 days after injury.Robo1 was upregulated in vimentin-positive cells and migrating Schwann cells inside the nerve bridge.Robo1 was also upregulated in Schwann cells of the distal nerve stump within 14 days after injury.Our findings indicate that Slit3 is the major ligand expressed in the nerve bridge and distal nerve stump during peripheral nerve regeneration,and Slit3/Robo signaling could play a key role in peripheral nerve repair after injury.This study was approved by Plymouth University Animal Welfare Ethical Review Board (approval No.30/3203) on April 12,2014.     

Lateral C1–C2 dislocation complicating a type II odontoid fracture

We describe a unique C1–C2 lateral dislocation complicating a displaced type II odontoid fracture. We report a 63-year-old female pedestrian involved in a motor vehicle accident who required posterior open reduction and segmental C1–C2 instrumentation and fusion. Radiological examination of the cervical spine demonstrated a lateral dislocation of the atlantoaxial joint with a displaced type II fracture of the odontoid, fracture of the right lateral mass of C1 and left superior articular facet of C2. Neurological examination revealed the patient to be myelopathic and closed halo traction failed to achieve reduction. Due to the irreducible nature of the dislocation, posterior open reduction and segmental C1–C2 instrumentation and fusion was performed. The dislocated C1–C2 articulation was successfully reduced surgically with subsequent bony fusion and resolution of all neurological symptoms and signs at final follow-up. To our knowledge, this the first report of this type of injury. We also review the related literature on this unique injury pattern.     

PEN–2 gene mutation in a familial Alzheimer’s disease case

Genetic evidence indicates a central role of cerebral accumulation of β–amyloid (Aβ) in the pathogenesis of Alzheimer’s disease (AD). Beside presenilin 1 and 2, three other recently discovered proteins (Aph 1, PEN 2 and nicastrin) are associated with γ–secretase activity, the enzymatic complex generating Aβ. Alterations in genes encoding these proteins were candidates for a role in AD. The PEN 2 gene was examined for unknown mutations and polymorphisms in sporadic and familial Alzheimer patients. Samples from age–matched controls (n = 253), sporadic AD (SAD, n = 256) and familial AD (FAD, n = 140) were screened with DHPLC methodology followed by sequencing. Scanning the gene identified for the first time a missense mutation (D90N) in a patient with FAD. Three intronic polymorphisms were also identified, one of which had a higher presence of the mutated allele in AD subjects carrying the allele ε4 of apolipoprotein E than controls. The pathogenic role of the PEN–2 D90N mutation in AD is not clear, but the findings might lead to new studies on its functional and genetic role.*These two authors contributed equally to the paper.     

Saccades and Eye–Head Coordination in Ataxia with Oculomotor Apraxia Type 2

Ataxia with oculomotor apraxia type 2 (AOA2) is one of the most frequent autosomal recessive cerebellar ataxias. Oculomotor apraxia refers to horizontal gaze failure due to deficits in voluntary/reactive eye movements. These deficits can manifest as increased latency and/or hypometria of saccades with a staircase pattern and are frequently associated with compensatory head thrust movements. Oculomotor disturbances associated with AOA2 have been poorly studied mainly because the diagnosis of oculomotor apraxia was based on the presence of compensatory head thrusts. The aim of this study was to characterise the nature of horizontal gaze failure in patients with AOA2 and to demonstrate oculomotor apraxia even in the absence of head thrusts. Five patients with AOA2, without head thrusts, were tested in saccadic tasks with the head restrained or free to move and their performance was compared to a group of six healthy participants. The most salient deficit of the patients was saccadic hypometria with a typical staircase pattern. Saccade latency in the patients was longer than controls only for memory-guided saccades. In the head-free condition, head movements were delayed relative to the eye and their amplitude and velocity were strongly reduced compared to controls. Our study emphasises that in AOA2, hypometric saccades with a staircase pattern are a more reliable sign of oculomotor apraxia than head thrust movements. In addition, the variety of eye and head movements’ deficits suggests that, although the main neural degeneration in AOA2 affects the cerebellum, this disease affects other structures.