Celiac and superior mesenteric ganglia removal improves glucose tolerance and reduces pancreas islet size.

The sympathetic nervous system is crucial for the regulation of visceral organ function. For instance, the activation of the sympathetic nervous system promotes glycogenolysis in the liver and modulates glucagon and insulin release from the pancreas, thereby raising blood glucose levels. A decrease in sympathetic nerve activity has the opposite effect. Although such acute effects of sympathetic activity changes have been studied, their long-term outcomes have not been previously examined. In this study, we removed the celiac/superior mesenteric ganglia, where sympathetic postganglionic neurons innervating pancreas and liver locate, and examined its effects on glucose homeostasis and islet size several weeks after surgery. Consistent with the reduction in gluconeogenesis, glucose tolerance improved in gangliectomized mice. However, contrary to our expectation that the inhibition of pancreatic function by sympathetic nerves would be relieved with gangliectomy, insulin or C-peptide release did not increase. Examining the size distribution of pancreatic islets, we identified that the gangliectomy led to a size reduction in large islets and a decrease in the proportion of α and ß cells within each islet, as analyzed by immunostaining for insulin and glucagon, respectively. These results indicate that the absence of sympathetic nerve activity reduces the size of the pancreatic islets within a few weeks to reinstate the homeostatic mechanism of blood glucose levels.

Motor innervation directs the correct development of the mouse sympathetic nervous system.

The sympathetic nervous system controls bodily functions including vascular tone, cardiac rhythm, and the "fight-or-flight response". Sympathetic chain ganglia develop in parallel with preganglionic motor nerves extending from the neural tube, raising the question of whether axon targeting contributes to sympathetic chain formation. Using nerve-selective genetic ablations and lineage tracing in mouse, we reveal that motor nerve-associated Schwann cell precursors (SCPs) contribute sympathetic neurons and satellite glia after the initial seeding of sympathetic ganglia by neural crest. Motor nerve ablation causes mispositioning of SCP-derived sympathoblasts as well as sympathetic chain hypoplasia and fragmentation. Sympathetic neurons in motor-ablated embryos project precociously and abnormally towards dorsal root ganglia, eventually resulting in fusion of sympathetic and sensory ganglia. Cell interaction analysis identifies semaphorins as potential motor nerve-derived signaling molecules regulating sympathoblast positioning and outgrowth. Overall, central innervation functions both as infrastructure and regulatory niche to ensure the integrity of peripheral ganglia morphogenesis.

Surgical Lumbar Sympathectomy in Mice.

Peripheral nerve injuries are common, and full functional recovery after injury is achieved in only 10% of patients. The sympathetic nervous system plays many critical roles in maintaining bodily homeostasis, but it has rarely been studied in the context of peripheral nerve injury. The extent of postganglionic sympathetic neuronal functions in distal targets in the periphery is currently unclear. To better explore the role of sympathetic innervation of peripheral targets, a surgical "knock-out" model provides an alternative approach. Although this can be achieved chemically, chemical destruction of postganglionic sympathetic neurons can be nonspecific and dose-dependent. The use of a surgical lumbar sympathectomy in mice, once thought to be "virtually not practicable" in small animals, allows for specific targeting of postganglionic sympathetic neurons that innervate the hind limbs. This manuscript describes how to surgically remove the L2-L5 lumbar sympathetic ganglia from a mouse as a survival surgery, which reliably decreases the hind paw sweat response and the number of sympathetic axons in the sciatic nerve.

Effect duration of lumbar sympathetic ganglion neurolysis in patients with complex regional pain syndrome: a prospective observational study.

Lumbar sympathetic ganglion neurolysis (LSGN) has been used for long-term pain relief in patients with complex regional pain syndrome (CRPS). However, the actual effect duration of LSGN has not been accurately measured. This prospective observational study measured the effect duration of LSGN in CRPS patients and investigated the relationship between temperature change and pain relief. After performing LSGN, the skin temperatures of both the maximum pain site and the plantar area in the affected and unaffected limbs were measured by infrared thermography, and pain intensity was assessed before and at 2 weeks, 1 month, and 3 months. The median time to return to baseline temperature was calculated using survival analysis. The skin temperature increased significantly at all-time points relative to baseline in both regions (maximum pain site: 1.4 °C ± 1.0 °C, plantar region: 1.28 °C ± 0.8 °C, all P < 0.001). The median time to return to baseline temperature was 12 weeks (95% confidence interval [CI] 7.7-16.3) at the maximum pain site and 12 weeks (95% CI 9.4-14.6) at the plantar area. Pain intensity decreased significantly relative to baseline, at all-time points after LSGN. In conclusion, the median duration of the LSGN is estimated to be 12 weeks.

Neural crest origin of sympathetic neurons at the dawn of vertebrates.

The neural crest is an embryonic stem cell population unique to vertebrates1 whose expansion and diversification are thought to have promoted vertebrate evolution by enabling emergence of new cell types and structures such as jaws and peripheral ganglia2. Although jawless vertebrates have sensory ganglia, convention has it that trunk sympathetic chain ganglia arose only in jawed vertebrates3-8. Here, by contrast, we report the presence of trunk sympathetic neurons in the sea lamprey, Petromyzon marinus, an extant jawless vertebrate. These neurons arise from sympathoblasts near the dorsal aorta that undergo noradrenergic specification through a transcriptional program homologous to that described in gnathostomes. Lamprey sympathoblasts populate the extracardiac space and extend along the length of the trunk in bilateral streams, expressing the catecholamine biosynthetic pathway enzymes tyrosine hydroxylase and dopamine ß-hydroxylase. CM-DiI lineage tracing analysis further confirmed that these cells derive from the trunk neural crest. RNA sequencing of isolated ammocoete trunk sympathoblasts revealed gene profiles characteristic of sympathetic neuron function. Our findings challenge the prevailing dogma that posits that sympathetic ganglia are a gnathostome innovation, instead suggesting that a late-developing rudimentary sympathetic nervous system may have been characteristic of the earliest vertebrates.

Protocol for the isolation of the mouse sympathetic splanchnic-celiac-superior mesenteric ganglion complex.

Neurons that originate from pre-vertebral sympathetic ganglia, the splanchnic-celiac-superior mesenteric ganglion complex (SCSMG) in mouse, have important roles in control of organs of the upper abdomen. Here, we present a protocol for the isolation of the mouse sympathetic SCSMG. We describe steps for surgical incision, ganglia isolation, ganglia fine dissection, and whole-mount SCSMG after clearing-enhanced 3D (Ce3D) clearing method and immunohistochemistry. Given the importance of mice in studies of that control, this protocol aims to assist biomedical researchers in the dissection of the mouse SCSMG.

Neuron parvum fluorescens, un Término con Influencia Anglo-Greco-Latina. Propuesta a Terminologia Neuroanatomica y Terminologia Histologica / Neuron Parvum Fluorescens, a Term with Anglo-Greco-Latin Influence. A Proposal to Terminologia Neuroanatomica and Terminologia Histologica

Las terminologías son utilizadas como instrumento lingüístico que permite la transmisión de conocimiento de manera precisa y sin ambigüedades en el ámbito de las ciencias. Los lineamientos de la Federative International Programme for Anatomical Terminology (FIPAT) refieren que la denominación de nombres estructurales debe ser descriptivos e informativos. Este estudio analiza las raíces lingüísticas que componen el término Neuron parvum valde fluorescens vigente en Terminologia Histologica y el término Neuron parvum fluorescens vigente en Terminologia Neuroanatomica. Las células pequeñas intensamente fluorescentes son neuronas que se encuentran en el sistema nervioso autónomo, distribuidas en los ganglios simpáticos. Estas células presentan sinapsis aferentes con terminales nerviosas simpáticas preganglionares y sinapsis eferentes con las dendritas de las neuronas posganglionares. Su función es regular la transmisión ganglionar, actuando como interneuronas con señalización paracrina y endocrina. Además, se caracterizan por ser células fluorescentes, que expresan catecolaminas; serotonina, noradrenalina y dopamina. Se realizó una búsqueda en Terminologia Histologica y Terminologia Neuroanatomica, con una traducción de los términos al español. Además, la búsqueda se complementó en un diccionario etimológico en inglés para los términos correspondientes. Esta investigación encontró diferencia entre la traducción del latín al español del término fluorescens, quien posee un origen etimológico muy diferente a su significado en español. El término Neuron parvum valde fluorescens en Terminologia Histologica y el término Neuron parvum fluorescens en Terminologia Neuroanatomica, identifican a la misma estructura. Se sugiere reemplazar ambos términos por Cateconeuron ganglionare, entregando así una correcta descripción de este tipo de neurona, considerando su ubicación y función. Además, de esta manera ser un término concordante en latín para su incorporación en Terminologia Neuroanatomica y Terminologia Histologica.

SUMMARY: Terminologies are used as a linguistic tool to convey knowledge in a precise and unambiguous manner in science. The guidelines of the Federative International Programme for Anatomical Terminology (FIPAT) state that the names given to structures should be both descriptive and informative. This study analyses the linguistic roots of the term Neuron parvum valde fluorescens in Terminologia Histologica and the term Neuron parvum fluorescens in Terminologia Neuroanatomica. Small intensely fluorescent cells are neurons found in the autonomic nervous system, distributed in the sympathetic ganglia, they have afferent synapses with preganglionic sympathetic nerve terminals and efferent synapses with the dendrites of postganglionic neurons, whose function is to regulate ganglionic transmission, acting as interneurons with paracrine and endocrine signalling. They are also characterized as fluorescent cells, producing the catecholamines: serotonin, noradrenaline and dopamine. A search was carried out in Terminologia Histologica and Terminologia Neuroanatomica, with a translation of the terms into Spanish. This was complemented by a search in an English etymological dictionary for the corresponding terms. This research found a difference between the Latin to English translation of the term fluorescens, which has a very different etymological origin to its English meaning. The term Neuron parvum valde fluorescens in Terminologia Histologica and the term Neuron parvum fluorescens in Terminologia Neuroanatomica identify the same structure. The proposal is to replace both terms with Cateconeuron ganglionare, thus affording an accurate description of this type of neuron, considering its location and function. Moreover, it would also be a concordant term in Latin for its incorporation into the Terminologia Neuroanatomica and Terminologia Histologica.

The differences in the anatomy of the thoracolumbar and sacral autonomic outflow are quantitative.

PURPOSE: We have re-evaluated the anatomical arguments that underlie the division of the spinal visceral outflow into sympathetic and parasympathetic divisions. METHODOLOGY: Using a systematic literature search, we mapped the location of catecholaminergic neurons throughout the mammalian peripheral nervous system. Subsequently, a narrative method was employed to characterize segment-dependent differences in the location of preganglionic cell bodies and the composition of white and gray rami communicantes. RESULTS AND CONCLUSION: One hundred seventy studies were included in the systematic review, providing information on 389 anatomical structures. Catecholaminergic nerve fibers are present in most spinal and all cranial nerves and ganglia, including those that are known for their parasympathetic function. Along the entire spinal autonomic outflow pathways, proximal and distal catecholaminergic cell bodies are common in the head, thoracic, and abdominal and pelvic region, which invalidates the "short-versus-long preganglionic neuron" argument. Contrary to the classically confined outflow levels T1-L2 and S2-S4, preganglionic neurons have been found in the resulting lumbar gap. Preganglionic cell bodies that are located in the intermediolateral zone of the thoracolumbar spinal cord gradually nest more ventrally within the ventral motor nuclei at the lumbar and sacral levels, and their fibers bypass the white ramus communicans and sympathetic trunk to emerge directly from the spinal roots. Bypassing the sympathetic trunk, therefore, is not exclusive for the sacral outflow. We conclude that the autonomic outflow displays a conserved architecture along the entire spinal axis, and that the perceived differences in the anatomy of the autonomic thoracolumbar and sacral outflow are quantitative.

Changes in the expression of satellite glial cell-specific markers during postnatal development of rat sympathetic ganglia.

The sympathetic ganglia represent a final motor pathway that mediates homeostatic "fight and flight" responses in the visceral organs. Satellite glial cells (SGCs) form a thin envelope close to the neuronal cell body and synapses in the sympathetic ganglia. This unique morphological feature suggests that neurons and SGCs form functional units for regulation of sympathetic output. In the present study, we addressed whether SGC-specific markers undergo age-dependent changes in the postnatal development of rat sympathetic ganglia. We found that fatty acid-binding protein 7 (FABP7) is an early SGC marker, whereas the S100B calcium-binding protein, inwardly rectifying potassium channel, Kir4.1 and small conductance calcium-activated potassium channel, SK3 are late SGC markers in the postnatal development of sympathetic ganglia. Unlike in sensory ganglia, FABP7 + SGC was barely detectable in adult sympathetic ganglia. The expression of connexin 43, a gap junction channel gradually increased with age, although it was detected in both SGCs and neurons in sympathetic ganglia. Glutamine synthetase was expressed in sensory, but not sympathetic SGCs. Unexpectedly, the sympathetic SGCs expressed a water-selective channel, aquaporin 1 instead of aquaporin 4, a pan-glial marker. However, aquaporin 1 was not detected in the SGCs encircling large neurons. Nerve injury and inflammation induced the upregulation of glial fibrillary acidic protein, suggesting that this protein is a hall marker of glial activation in the sympathetic ganglia. In conclusion, our findings provide basic information on the in vivo profiles of specific markers for identifying sympathetic SGCs at different stages of postnatal development in both healthy and diseased states.

Immunohistochemical phenotype of sensory neurons associated with sympathetic plexuses in the trigeminal ganglia of adult nerve growth factor transgenic mice.

Following peripheral nerve injury, postganglionic sympathetic axons sprout into the affected sensory ganglia and form perineuronal sympathetic plexuses with somata of sensory neurons. This sympathosensory coupling contributes to the onset and persistence of injury-induced chronic pain. We have documented the presence of similar sympathetic plexuses in the trigeminal ganglia of adult mice that ectopically overexpress nerve growth factor (NGF), in the absence of nerve injury. In this study, we sought to further define the phenotype(s) of these trigeminal sensory neurons having sympathetic plexuses in our transgenic mice. Using quantitative immunofluorescence staining analyses, we show that the invading sympathetic axons specifically target sensory somata immunopositive for several biomarkers: NGF high-affinity receptor tyrosine kinase A (trkA), calcitonin gene-related peptide (CGRP), neurofilament heavy chain (NFH), and P2X purinoceptor 3 (P2X3). Based on these phenotypic characteristics, the majority of the sensory somata surrounded by sympathetic plexuses are likely to be NGF-responsive nociceptors (i.e., trkA expressing) that are peptidergic (i.e., CGRP expressing), myelinated (i.e., NFH expressing), and ATP sensitive (i.e., P2X3 expressing). Our data also show that very few sympathetic plexuses surround sensory somata expressing other nociceptive (pain) biomarkers, including substance P and acid-sensing ion channel 3. No sympathetic plexuses are associated with sensory somata that display isolectin B4 binding. Though the cellular mechanisms that trigger the formation of sympathetic plexus (with and without nerve injury) remain unknown, our new observations yield an unexpected specificity with which invading sympathetic axons appear to target a precise subtype of nociceptors. This selectivity likely contributes to pain development and maintenance associated with sympathosensory coupling.

Targeted ablation of the left middle cervical ganglion prevents ventricular arrhythmias and cardiac injury induced by AMI.

Cardiac sympathetic overactivation is a critical driver in the progression of acute myocardial infarction (AMI). The left middle cervical ganglion (LMCG) is an important extracardiac sympathetic ganglion. However, the regulatory effects of LMCG on AMI have not yet been fully documented. In the present study, we detected that the LMCG was innervated by abundant sympathetic components and exerted an excitatory effect on the cardiac sympathetic nervous system in response to stimulation. In canine models of AMI, targeted ablation of LMCG reduced the sympathetic indexes of heart rate variability and serum norepinephrine, resulting in suppressed cardiac sympathetic activity. Moreover, LMCG ablation could improve ventricular electrophysiological stability, evidenced by the prolonged ventricular effective refractory period, elevated action potential duration, increased ventricular fibrillation threshold, and enhanced connexin43 expression, consequently showing antiarrhythmic effects. Additionally, compared with the control group, myocardial infarction size, circulating cardiac troponin I, and myocardial apoptosis were significantly reduced, accompanied by preserved cardiac function in canines subjected to LMCG ablation. Finally, we performed the left stellate ganglion (LSG) ablation and compared its effects with LMCG destruction. The results indicated that LMCG ablation prevented ventricular electrophysiological instability, cardiac sympathetic activation, and AMI-induced ventricular arrhythmias with similar efficiency as LSG denervation. In conclusion, this study demonstrated that LMCG ablation suppressed cardiac sympathetic activity, stabilized ventricular electrophysiological properties and mitigated cardiomyocyte death, resultantly preventing ischemia-induced ventricular arrhythmias, myocardial injury, and cardiac dysfunction. Neuromodulation therapy targeting LMCG represented a promising strategy for the treatment of AMI.

Computed tomographic manifestations of celiac ganglia between hypertensive and non-hypertensive population.

The celiac ganglion (CG) is associated with the sympathetic nervous system (SNS) and plays an important role in the pathogenesis of hypertension. The characteristics of the CG in patients with hypertension remain unknown. The aim of our study was to explore the differences in celiac ganglia (CGs) characteristics between hypertensive and non-hypertensive populations using computed tomography (CT). CGs manifestations on multidetector row CT in 1003 patients with and without hypertension were retrospectively analyzed. The morphological characteristics and CT values of the left CGs were recorded. The CT values of the ipsilateral adrenal gland (AG) and crus of the diaphragm (CD) were also measured. The left CG was located between the left AG and CD, and most CGs were long strips. The frequency of visualization of the left CGs was higher in the hypertension group than in the non-hypertension group (p < .05). There were no significant differences in the maximum diameter, size, and shape ratio of the left CGs between the two groups (p > .05). Except for the left CG in the arterial phase, the CT values of the left CG and AG in the non-hypertensive group were higher than those in the hypertension group (p < .05). The venous phase enhancement of the left CG in the non-hypertension group was significantly higher than that in the hypertension group (p < .05). Our findings reveal that CGs have characteristic manifestations in the hypertensive population. As important targets of the SNS, CGs have the potential to regulate blood pressure.

Reference gene recommendations and PACAP receptor expression in murine sympathetic ganglia of the autonomic nervous system that innervate adipose tissues after chronic cold exposure.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is an important regulator of the stress response in mammals, influencing both the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS). PACAP has been reported to influence energy homeostasis, including adaptive thermogenesis, an energy burning process in adipose tissue regulated by the SNS in response to cold stress and overfeeding. While research suggests PACAP acts centrally at the level of the hypothalamus, knowledge of PACAP's role within the sympathetic nerves innervating adipose tissues in response to metabolic stressors is limited. This work shows, for the first time, gene expression of PACAP receptors in stellate ganglia and highlights some differential expression with housing temperature. Additionally, we present our dissection protocol, analysis of tyrosine hydroxylase gene expression as a molecular biomarker for catecholamine producing tissue and recommend three stable reference genes for the normalization of quantitative real time-polymerase chain reaction (qRT-PCR) data when working with this tissue. This study adds to information about neuropeptide receptor expression in peripheral ganglia of the sympathetic nervous system innervating adipose tissue and provides insight into PACAP's role in the regulation of energy metabolism.

Downregulation of Bmal1 Expression in Celiac Ganglia Protects against Hepatic Ischemia-Reperfusion Injury.

Hepatic ischemia-reperfusion injury (HIRI) significantly contributes to liver dysfunction following liver transplantation and hepatectomy. However, the role of the celiac ganglion (CG) in HIRI remains unclear. Adeno-associated virus was used to silence Bmal1 expression in the CG of twelve beagles that were randomly assigned to the Bmal1 knockdown group (KO-Bmal1) and the control group. After four weeks, a canine HIRI model was established, and CG, liver tissue, and serum samples were collected for analysis. The virus significantly downregulated Bmal1 expression in the CG. Immunofluorescence staining confirmed a lower proportion of c-fos+ and NGF+ neurons in TH+ cells in the KO-Bmal1 group than in the control group. The KO-Bmal1 group exhibited lower Suzuki scores and serum ALT and AST levels than the control group. Bmal1 knockdown significantly reduced liver fat reserve, hepatocyte apoptosis, and liver fibrosis, and it increased liver glycogen accumulation. We also observed that Bmal1 downregulation inhibited the hepatic neurotransmitter norepinephrine, neuropeptide Y levels, and sympathetic nerve activity in HIRI. Finally, we confirmed that decreased Bmal1 expression in CG reduces TNF-α, IL-1ß, and MDA levels and increases GSH levels in the liver. The downregulation of Bmal1 expression in CG suppresses neural activity and improves hepatocyte injury in the beagle model after HIRI.

Celiac ganglia neurolysis suppresses high blood pressure in rats.

The efficacy of renal denervation in the treatment of resistant hypertension has been controversial, and new strategies for its therapy are urgently needed. We performed the celiac ganglia neurolysis (CGN) or sham surgery on both spontaneously hypertensive rat (SHR) and Dahl salt-sensitive rat models of hypertension. Following CGN surgery in both strains, systolic blood pressure, diastolic blood pressure and mean arterial pressure were all lower than the levels in the respective sham surgery rats, which were maintained until the end of the study, 18 weeks postoperatively in SHRs and 12 weeks postoperatively in Dahl rats. CGN therapy destroyed ganglion cell structure and significantly inhibited celiac ganglia nerve viability. Four and twelve weeks after CGN, the plasma renin, angiotensin II and aldosterone levels were markedly attenuated, and the nitric oxide content was significantly increased in the CGN group compared with the respective sham surgery rats. However, CGN did not result in statistical difference in malondialdehyde levels compared with sham surgery in both strains. The CGN has efficacy in reducing high blood pressure and may be an alternative for resistant hypertension. Minimally invasive endoscopic ultrasound-guided celiac ganglia neurolysis (EUS-CGN) and percutaneous CGN are safe and convenient treatment approaches. Moreover, for hypertensive patients who need surgery due to abdominal disease or pain relief from pancreatic cancer, intraoperative CGN or EUS-CGN will be a good choice for hypertension therapy. The graphical abstract of antihypertensive effect of CGN.

Anatomical variations of the thoracic sympathetic ganglions and their effects on sympathicotomy for primary palmar hyperhidrosis.

PURPOSE: The results and side effects of sympathicotomy for primary palmar hyperhidrosis (PPH) can vary due to anatomical variations of the sympathetic ganglions. The aim of our study was to clarify anatomical variations of the sympathetic ganglions by near-infrared (NIR) thoracoscopy and determine their effects on sympathicotomy for PPH. METHODS: The cases of 695 consecutive patients with PPH treated with either R3 or R4 sympathicotomy either by normal thoracoscopy or by NIR fluorescent thoracoscopy between March 2015 and June 2021 were retrospectively reviewed and followed up. RESULTS: The variation rate of third and fourth ganglions was 14.7% and 13.3% on the right side and 8.3% and 11.1% on the left side. Real T3 sympathicotomy (RTS3) was more effective than real T4 sympathicotomy (RTS4) in the short-term and long-term follow-up (p < 0.001 and p < 0.001, respectively). RTS3 was more satisfactory than RTS4 in the long-term follow-up (p = 0.03), but no significant difference was found in the short-term follow-up (p = 0.24). The incidence and severity of compensatory hyperhidrosis (CH) in the areas of the chest and back in the RTS4 group were significantly lower than those in the RTS3 group according to both the short-term results (12.92% vs. 26.19%, p < 0.001; 17.97% vs. 33.33%, p = 0.002, respectively) and the long-term results (19.66% vs. 28.57%, p = 0.017; 21.35% vs. 34.52%, p < 0.001, respectively). CONCLUSIONS: RTS3 may be more effective than RTS4 for PPH. However, RTS4 appears to be associated with a lower incidence and severity of CH in the areas of the chest and back than RTS3. NIR intraoperative imaging of thoracic sympathetic ganglions may improve the quality of sympathicotomy surgeries.

Follow-up of at least 3 years after ganglion impar block for control of chronic coccygodynia.

INTRODUCTION: Although it is well known that ganglion impar block (GIB) reduces pain in the short term in patients with chronic coccygodynia, there are insufficient data on long-term treatment outcomes. The aim of this study was to examine the long-term outcomes of patients who underwent GIB for chronic coccygodynia and possible factors that might affect these outcomes. METHODS: The pre-treatment, 1st-hour, and 3rd-week numeric rating scale (NRS) scores of patients who underwent GIB 36-119 (min-max) months ago (between November 2011 and October 2018) due to coccygodynia were obtained from the medical records. Final NRS scores and presence of factors that may affect success such as accompanying low back pain (LBP) were questioned via telephone interviews. Treatment success was defined as a 50% or more reduction in final NRS scores compared with pre-treatment NRS scores. RESULTS: Telephone interviews were made with 70 patients. Treatment success was achieved in 55.7% of the patients. The patients were divided into two groups as those who achieved treatment success (group A) and those who could not (group B) and were compared. The NRS scores at the 3rd week and the number of patients with LBP in the group B were significantly higher than the group A. No serious complications developed in any patients. CONCLUSION: In patients with chronic coccygodynia, GIB is an effective and safe treatment option for pain reduction in the long term. Accompanying LBP and high pain scores in the 3rd week after injection should be considered as parameters that negatively affect long-term treatment success.

Epigenetic Up-Regulation of ADAMTS4 in Sympathetic Ganglia is Involved in the Maintenance of Neuropathic Pain Following Nerve Injury.

Sympathetic axonal sprouting into dorsal root ganglia is a major phenomenon implicated in neuropathic pain, and sympathetic ganglia blockage may relieve some intractable chronic pain in animal pain models and clinical conditions. These suggest that sympathetic ganglia participated in the maintenance of chronic pain. However, the molecular mechanism underlying sympathetic ganglia-mediated chronic pain is not clear. Here, we found that spared nerve injury treatment upregulated the expression of ADAMTS4 and AP-2α protein and mRNA in the noradrenergic neurons of sympathetic ganglia during neuropathic pain maintenance. Knockdown the ADAMTS4 or AP-2α by injecting specific retro scAAV-TH (Tyrosine Hydroxylase)-shRNA ameliorated the mechanical allodynia induced by spared nerve injury on day 21 and 28. Furthermore, chromatin immunoprecipitation and coimmunoprecipitation assays found that spared nerve injury increased the recruitment of AP-2α to the ADAMTS4 gene promoter, the interaction between AP-2α and histone acetyltransferase p300 and the histone H4 acetylation on day 28. Finally, knockdown the AP-2α reduced the acetylation of H4 on the promoter region of ADAMTS4 gene and suppressed the increase of ADAMTS4 expression induced by spared nerve injury. Together, these results suggested that the enhanced interaction between AP-2α and p300 mediated the epigenetic upregulation of ADAMTS4 in sympathetic ganglia noradrenergic neurons, which contributed to the maintenance of spared nerve injury induced neuropathic pain.