Protein Arginine Methyltransferase 5 Contributes to Paclitaxel-Induced Neuropathic Pain by Activating Transient Receptor Potential Vanilloid 1 Epigenetic Modification in Dorsal Root Ganglion.

BACKGROUND: Paclitaxel (PTX), which is a first-line chemotherapy drug used to treat various types of cancers, exhibits peripheral neuropathy as a common side effect that is difficult to treat. Protein arginine methyltransferase 5 (PRMT 5) is a key regulator of the chemotherapy response, as chemotherapy drugs induce PRMT5 expression. However, little is known about the PRMT5-mediated epigenetic mechanisms involved in PTX-induced neuropathic allodynia. METHODS: Sprague-Dawley rats were intraperitoneally given PTX to induce neuropathic pain. Biochemical analyses were conducted to measure the protein expression levels in the dorsal root ganglion (DRG) of the animals. The von Frey test and hot plate test were used to evaluate nociceptive behaviors. RESULTS: PTX increased the PRMT5 (mean difference [MD]: 0.68, 95% confidence interval [CI], 0.88-0.48; P < .001 for vehicle)-mediated deposition of histone H3R2 dimethyl symmetric (H3R2me2s) at the transient receptor potential vanilloid 1 ( Trpv1 ) promoter in the DRG. PRMT5-induced H3R2me2s recruited WD repeat domain 5 (WDR5) to increase trimethylation of lysine 4 on histone H3 (H3K4me3) at Trpv1 promoters, thus resulting in TRPV1 transcriptional activation (MD: 0.65, 95% CI, 0.82-0.49; P < .001 for vehicle) in DRG in PTX-induced neuropathic pain. Moreover, PTX increased the activity of NADPH oxidase 4 (NOX4) (MD: 0.66, 95% CI, 0.81-0.51; P < .001 for vehicle), PRMT5-induced H3R2me2s, and WDR5-mediated H3K4me3 in the DRG in PTX-induced neuropathic pain. Pharmacological antagonism and the selective knockdown of PRMT5 in DRG neurons completely blocked PRMT5-mediated H3R2me2s, WDR5-mediated H3K4me3, or TRPV1 expression and neuropathic pain development after PTX injection. Remarkably, NOX4 inhibition not only attenuated allodynia behavior and reversed the above-mentioned signaling but also reversed NOX4 upregulation via PTX. CONCLUSIONS: Thus, the NOX4/PRMT5-associated epigenetic mechanism in DRG has a dominant function in the transcriptional activation of TRPV1 in PTX-induced neuropathic pain.

Melatonin Relieves Paclitaxel-Induced Neuropathic Pain by Regulating pNEK2-Dependent Epigenetic Pathways in DRG Neurons.

The neurohormone melatonin (MLT) demonstrates promising potential in ameliorating neuropathic pain induced by paclitaxel (PTX) chemotherapy. However, little is known about its protective effect on dorsal root ganglion (DRG) neurons in neuropathic pain resulting from the chemotherapeutic drug PTX. Here, PTX-treated rats revealed that intrathecal administration of MLT dose-dependently elevated hind paw withdrawal thresholds and latency, indicating that MLT significantly reversed PTX-induced neuropathic pain. Mechanistically, the analgesic effects of MLT were found to be mediated via melatonin receptor 2 (MT2), as pretreatment with an MT2 receptor antagonist inhibited these effects. Moreover, intrathecal MLT injection reversed the pNEK2-dependent epigenetic program induced by PTX. All of the effects caused by MLT were blocked by pretreatment with an MT2 receptor-selective antagonist, 4P-PDOT. Remarkably, multiple MLT administered during PTX treatment (PTX+MLTs) exhibited not only rapid but also lasting reversal of allodynia/hyperalgesia compared to single-bolus MLT administered after PTX treatment (PTX+MLT). In addition, PTX+MLTs exhibited greater efficacy in reversing PTX-induced alterations in pRSK2, pNEK2, JMJD3, H3K27me3, and TRPV1 expression and interaction in DRG neurons than PTX+MLT. These results indicated that MLT administered during PTX treatment reduced the incidence and/or severity of neuropathy and had a better inhibitory effect on the pNEK2-dependent epigenetic program compared to MLT administered after PTX treatment. In conclusion, MLT/MT2 is a promising therapy for the treatment of pNEK2-dependent painful neuropathy resulting from PTX treatment. MLT administered during PTX chemotherapy may be more effective in the prevention or reduction of PTX-induced neuropathy and maintaining quality.

Phosphorylated Upstream Frameshift 1-dependent Nonsense-mediated µ-Opioid Receptor mRNA Decay in the Spinal Cord Contributes to the Development of Neuropathic Allodynia-like Behavior in Rats.

BACKGROUND: Nonsense-mediated messenger RNA (mRNA) decay increases targeted mRNA degradation and has been implicated in the regulation of gene expression in neurons. The authors hypothesized that nonsense-mediated µ-opioid receptor mRNA decay in the spinal cord is involved in the development of neuropathic allodynia-like behavior in rats. METHODS: Adult Sprague-Dawley rats of both sexes received spinal nerve ligation to induce neuropathic allodynia-like behavior. The mRNA and protein expression contents in the dorsal horn of animals were measured by biochemical analyses. Nociceptive behaviors were evaluated by the von Frey test and the burrow test. RESULTS: On Day 7, spinal nerve ligation significantly increased phosphorylated upstream frameshift 1 (UPF1) expression in the dorsal horn (mean ± SD; 0.34 ± 0.19 in the sham ipsilateral group vs. 0.88 ± 0.15 in the nerve ligation ipsilateral group; P < 0.001; data in arbitrary units) and drove allodynia-like behaviors in rats (10.58 ± 1.72 g in the sham ipsilateral group vs. 1.19 ± 0.31 g in the nerve ligation ipsilateral group, P < 0.001). No sex-based differences were found in either Western blotting or behavior tests in rats. Eukaryotic translation initiation factor 4A3 (eIF4A3) triggered SMG1 kinase (0.06 ± 0.02 in the sham group vs. 0.20 ± 0.08 in the nerve ligation group, P = 0.005, data in arbitrary units)-mediated UPF1 phosphorylation, leading to increased nonsense-mediated mRNA decay factor SMG7 binding and µ-opioid receptor mRNA degradation (0.87 ± 0.11-fold in the sham group vs. 0.50 ± 0.11-fold in the nerve ligation group, P = 0.002) in the dorsal horn of the spinal cord after spinal nerve ligation. Pharmacologic or genetic inhibition of this signaling pathway in vivo ameliorated allodynia-like behaviors after spinal nerve ligation. CONCLUSIONS: This study suggests that phosphorylated UPF1-dependent nonsense-mediated µ-opioid receptor mRNA decay is involved in the pathogenesis of neuropathic pain.

Video-Assisted Rigid Endoscopic Laser Ablation for Endobronchial Mucoepidermoid Carcinoma in Pediatrics Without Pulmonary Resections.

INTRODUCTION: Mucoepidermoid carcinoma (MEC) is a rare malignancy of primary endobronchial lesions in children. Early diagnosis is crucial for the disease, but it is often misdiagnosed as asthma or lung infection. Chest computed tomography and bronchoscopy are the most important diagnostic tools. Surgical resection is the current treatment of choice for low-grade MEC. In the past, lobectomy, sleeve lobectomy, or segmental resections were the most standard surgeries. Endoscopic treatment was used for lung preservation and effectual removal of the lesions. METHODS: A retrospective study of pediatric patients with primary endobronchial lesions who underwent rigid bronchoscopic laser ablation since 2010 was conducted. Pre-operative images, endoscopic pictures, post-operative images, histological analyses, and patients' clinical conditions were recorded and illustrated. RESULTS: Four patients were enrolled. Three patients presented initially with cough or hemoptysis. The lesion sites were the bronchus of the left upper lobe, left lower lobe, left main bronchus, and trachea. All patients underwent bronchoscopic laser ablation for tumor excision without anatomical resection. No major surgical complications were encountered. All patients survived without recurrence after a mean postoperative follow-up of 4.5 years (3-6 years). CONCLUSION: Video-assisted rigid endoscopic laser ablation for pediatric low-grade endobronchial MEC is a feasible, effective, and safe method. Close follow-up is essential for lung preservation management. EVIDENCE LEVEL: Level IV. TYPE OF STUDY: Case series with no comparison group.

Phosphate NIMA-Related Kinase 2-Dependent Epigenetic Pathways in Dorsal Root Ganglion Neurons Mediates Paclitaxel-Induced Neuropathic Pain.

BACKGROUND: The microtubule-stabilizing drug paclitaxel (PTX) is an important chemotherapeutic agent for cancer treatment and causes peripheral neuropathy as a common side effect that substantially impacts the functional status and quality of life of patients. The mechanistic role for NIMA-related kinase 2 (NEK2) in the progression of PTX-induced neuropathic pain has not been established. METHODS: Adult male Sprague-Dawley rats intraperitoneally received PTX to induce neuropathic pain. The protein expression levels in the dorsal root ganglion (DRG) of animals were measured by biochemical analyses. Nociceptive behaviors were evaluated by von Frey tests and hot plate tests. RESULTS: PTX increased phosphorylation of the important microtubule dynamics regulator NEK2 in DRG neurons and induced profound neuropathic allodynia. PTX-activated phosphorylated NEK2 (pNEK2) increased jumonji domain-containing 3 (JMJD3) protein, a histone demethylase protein, to specifically catalyze the demethylation of the repressive histone mark H3 lysine 27 trimethylation (H3K27me3) at the Trpv1 gene, thereby enhancing transient receptor potential vanilloid subtype-1 (TRPV1) expression in DRG neurons. Moreover, the pNEK2-dependent PTX response program is regulated by enhancing p90 ribosomal S6 kinase 2 (RSK2) phosphorylation. Conversely, intrathecal injections of kaempferol (a selective RSK2 activation antagonist), NCL 00017509 (a selective NEK2 inhibitor), NEK2-targeted siRNA, GSK-J4 (a selective JMJD3 inhibitor), or capsazepine (an antagonist of TRPV1 receptor) into PTX-treated rats reversed neuropathic allodynia and restored silencing of the Trpv1 gene, suggesting the hierarchy and interaction among phosphorylated RSK2 (pRSK2), pNEK2, JMJD3, H3K27me3, and TRPV1 in the DRG neurons in PTX-induced neuropathic pain. CONCLUSIONS: pRSK2/JMJD3/H3K27me3/TRPV1 signaling in the DRG neurons plays as a key regulator for PTX therapeutic approaches.

MicroRNA-489-3p attenuates neuropathic allodynia by regulating oncoprotein DEK/TET1-dependent epigenetic modification in the dorsal horn.

Originally characterized as an oncoprotein overexpressed in many forms of cancer that participates in numerous cellular pathways, DEK has since been well described regarding the regulation of epigenetic markers and transcription factors in neurons. However, its role in neuropathic allodynia processes remain elusive and intriguingly complex. Here, we show that DEK, which is induced in spinal dorsal horn neurons after spinal nerve ligation (SNL), is regulated by miR-489-3p. Moreover, SNL-induced decrease in miR-489-3p expression increased the expression of DEK, which recruited TET1 to the promoter fragments of the Bdnf, Grm5, and Stat3 genes, thereby enhancing their transcription in the dorsal horn. Remarkably, these effects were also induced by intrathecally administering naïve animals with miR-489-3p inhibitor, which could be inhibited by knockdown of TET1 siRNA or DEK siRNA. Conversely, delivery of intrathecal miR-489-3p-mimic into SNL rats attenuated allodynia behavior and reversed protein expression coupled to the promoter segments in the dorsal horn. Thus, a spinal miR-489-3p/DEK/TET1 transcriptional axis may contribute to neuropathic allodynia. These results may provide a new target for treating neuropathic allodynia.

Hybrid Retroperitoneoscopic Pyeloplasty for Congenital Ureteropelvic Junction Obstruction in Infants Weighing Less than 10 kg.

Introduction: Success rate of laparoscopic pyeloplasty for ureteropelvic junction obstruction (UPJO) in children is comparable with open pyeloplasty. Prolonged ileus and injury to adjacent viscera more often occurred in transperitoneal approach; however, longer operation time is noted in retroperitoneal approach. Purpose: This study presented a hybrid retroperitoneoscopic pyeloplasty (HRP), for congenital UPJO in infants weighing <10 kg. Materials and Methods: From February 2017 to June 2020, 10 HRP procedures were performed in 9 patients by 1 surgeon. Retroperitoneal dissection of the renal pelvis and the upper third ureter was first performed, followed by extracorporeal suturing for pyeloureterostomy. Results: Mean operative age and body weight were 4.23 ± 3.69 months and 6.18 ± 1.57 kg. Operative, CO2 inflation, and extracorporeal suture time were 147.9 ± 39.5, 40.6 ± 11.2, and 62.9 ± 26.1 minutes, respectively. Surgical outcome was confirmed by renal ultrasound and diuretic renogram. Postoperative follow-up duration was 15.2 ± 7.7 months. Three patients had postoperative febrile urinary tract infection and recovered after antibiotic treatment. Conclusion: In infants or smaller children with UPJO, the HRP procedure may be considered as an effective and minimally invasive alternative with shorter learning curve for inexperienced surgeons.

Genistein Suppressing the ROS-Induced Hypersensitivity of Rat Vagal Lung C-Fiber Afferents through an ERα-Mediated Mechanism.

Reactive oxygen species (ROS) may induce hypersensitivity of vagal lung C-fibers (VLCFs) through the interaction of transient receptor potential ankyirn 1 (TRPA1) and P2X receptors. Genistein is a soy-derived isoflavone that exerts antioxidant effects by binding to estrogen receptors (ERs), ERα and ERß. We investigated whether ER activation by genistein can suppress H2O2-mediated VLCF hypersensitivity and identified the types of ERs involved. Results revealed that subcutaneous injection of genistein or 4,4',4"-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT, a selective ERα agonist) can attenuate H2O2-induced VLCF hypersensitivity. The suppressive effects of genistein and PPT were inhibited by an additional treatment with ICI182780 (a nonselective ER antagonist) or 1,3-bis(4- hydroxyphenyl)-4-methyl-5-[4-(2-piperidinylethoxy)phenol]-1H-pyrazole dihydrochloride (MPP, a selective ERα antagonist). Treatment with a combination of PPT, HC030031 (a TRPA1 receptor antagonist), and iso-pyridoxalphosphate-6-azophenyl-2',5'-disulphonate (iso-PPADS, a P2X receptor antagonist) did not further inhibit H2O2-induced VLCF hypersensitivity as compared with combined HC030031 and iso-PPADS treatment. In conclusion, ERα activation by genistein can suppress H2O2- induced VLCF hypersensitivity through its functional interaction with TRPA1 and P2X receptors.

Reconsideration of Laparoscopic Kasai Operation for Biliary Atresia.

INTRODUCTION: Minimal invasive surgery for all kinds of surgical diseases had been practiced for years. The laparoscopic Kasai operation is one of the most challenging procedures and remains controversial for treating biliary atresia (BA). PURPOSE: This work presented the initial experience of our Institute and compared the outcomes of open and laparoscopic Kasai operations for BA. MATERIALS AND METHODS: Patients 18 years old and younger, and were operated in our Institute for BA from January 2011 to August 2017, were included in this study. General and operative data and outcomes from open and laparoscopic groups were retrospectively collected and analyzed. RESULTS: A total of 23 patients (13 for conventional open operation and 10 for the laparoscopic procedure) received Kasai portoenterostomy. The mean operative age and body weight in the open versus laparoscopic groups were 57.15 ± 20.14 days old and 4.03 ± 0.69 kg versus 57.70 ± 43.06 days old and 4.49 ± 1.48 kg, respectively, and no statistical difference was observed. The mean operative times were 209.62 ± 60.40 and 293.50 ± 39.09 minutes in the open and laparoscopic groups, respectively. The mean follow-up durations were 54.62 ± 22.00 and 23.30 ± 11.87 months for the open and laparoscopic patients, correspondingly. No statistically significant differences were observed for hospital stay and outcomes (including early jaundice clearance rate, episodes of cholangitis, and 2-year native liver survival rate) between the open and the laparoscopic Kasai operations. CONCLUSION: Experienced pediatric laparoscopic surgeons may reconsider the laparoscopic Kasai operation for application to BA treatment.

Perioperative parameter analysis of neonates and infants receiving laparoscopic surgery.

BACKGROUND: The field of laparoscopic surgery in neonates or younger infants has benefitted from recent progress. This study aimed to determine the correlation between patient characteristics and perioperative parameters, and to explore the feasibility of laparoscopic surgery in neonates and infants. METHODS: We retrospectively collected and analyzed data on neonates and infants who received laparoscopic surgery at our institute between January 2007 and August 2015. Perioperative data, surgical outcomes, and related complications were analyzed using Spearman rank correlation coefficient. RESULTS: A total of 82 patients (42 male and 40 female) were included in this study. The median operative age and the median operative body weight were 2.2 months and 4.2 kg, respectively. The median operative time was 3.5 hours, and the median insufflation time was 2.0 hours. The mean intraoperative end-tidal carbon dioxide (EtCO2) level was 37.6 mmHg, the median body temperature (BT) was 35.8°C, and the mean peak inspiratory pressure was 23.3 cmH2O. The median follow-up duration was 23.4 months. The intraoperative BT was significantly influenced by the operative age (p < 0.001, rs = 0.52) and body weight (p < 0.001, rs = 0.59). The intraoperative EtCO2 level was higher for longer operative time (p = 0.01, rs = 0.28) and insufflation time (p < 0.001, rs = 0.39); however, all values returned to normal when the CO2 insufflation was stopped. CONCLUSION: Laparoscopic surgery for neonates and infants can be safely performed by experienced surgeons. However, transient hypercarbia may rapidly ameliorate after CO2 insufflation is stopped.

Activation of cannabinoid CB1 receptors suppresses the ROS-induced hypersensitivity of rat vagal lung C-fiber afferents.

BACKGROUND: Reactive oxygen species (ROS), including H2O2, have been shown to induce hypersensitivity of vagal lung C-fibers (VLCFs) mainly through receptor potential ankyrin 1 (TRPA1) and P2X receptors. Cannabinoids (CBs) exert antinociceptive effects by binding to specific CB receptors, designated CB1 and CB2 (type 2) for type 1 and type 2, respectively. We investigated whether activation of CB receptors can suppress ROS-mediated VLCF hypersensitivity and, if so, what type(s) of CB receptors are involved. METHODS: Aerosolized H2O2 (0.05%) was inhaled by anesthetized spontaneously breathing rats (n = 304) to sensitize VLCFs. Airway reflex reactivity to intravenous capsaicin, a VLCF stimulant, was measured. Perivagal pretreatments with various types of agonists and antagonists, a technique that can modulate VLCF sensitivity, were made to delineate the roles of the CB receptors. RESULTS: Aerosolized H2O2 induced an augmented apneic response to capsaicin, which was blocked by bilateral vagotomy or by perivagal capsaicin treatment, suggesting that the response is mediated through VLCFs. Perivagal treatment with HU210 (a nonselective CB agonist) or ACPA (a selective CB1 receptor agonist), but not JWH133 (a CB2 receptor agonist), attenuated this H2O2-induced VLCF hypersensitivity. The suppressive effects of HU210 and ACPA were prevented by an additional treatment with AM251 (a selective CB1 antagonist), but not with AM630 (a selective CB2 antagonist). Perivagal treatment with a combination of ACPA, HC030031 (a TRPA1 receptor antagonist), and iso-PPADS (a P2X receptor antagonist) further attenuated the H2O2-induced VLCF hypersensitivity, as compared with treatment with a combination of HC030031 and iso-PPADS. CONCLUSIONS: Our results suggest that activation of CB1 receptors may suppress the ROS-mediated VLCF hypersensitivity through a mechanism that is at least partly distinct from the function of TRPA1 and P2X receptors.

Chylothorax after left side pneumothorax surgery managed by OK-432 pleurodesis: an effective alternative.

Chylothorax, a relatively rare complication of thoracic surgery, mostly occurs on the right side. We present a 16-year-old male who received thoracoscopic surgery for left spontaneous pneumothorax. Chylothorax developed on the postoperative 2(nd) day and resolved after diet control on the 4(th) day. Unfortunately, chylothorax recurred 2 weeks later. Chest drainage and nil per os with total parental nutrition were given but in vain. Thereafter, chemical pleurodesis with OK-432 was performed. Chylothorax resolved on the next day. The relevant literature is reviewed and possible pathogenesis clarified.

Acute uterine irritation provokes colonic motility via transient receptor potential A(1)-dependent spinal NR2B phosphorylation in rats.

BACKGROUND: Patients with inflammatory gynecological/obstetrical problems often complain of irritable bowel syndrome. The authors examined whether acute uterus irritation reflexively provokes colonic motility in rat preparations. METHODS: A modified colon manometry and striated abdominal muscle electromyogram activity in response to mustard oil (MO) instillation into the uterine horn were continuously recorded in anesthetized rats. The lumbosacral (L6-S1) dorsal horn was dissected to assess the level and the cellular location of phosphorylated NR2B subunit using Western blotting and immunofluorescence analysis, respectively. Finally, the uterine transient receptor potential A1 or spinal NR2B subunit was pharmacologically blocked to elucidate its roles. RESULTS: MO (0.1%, 0.2 ml) injected into the lower uterine horn dramatically provoked colonic hypermotility characterized by rhythmic colonic contractions (about 3-4 contractions per 10 min, n = 7) accompanied by synchronized electromyogram firing in the abdominal muscle (about 4-5 folds of control, n = 7). In addition to provoking colonic hypermotility, MO administration also up-regulated phosphorylated (about 2-3 folds of control, n = 7), but not total, NR2B expression in the dorsal horn neurons. Both intrathecal Ro 25-6981 (a selective NR2B subunit antagonist; 10 µM, 10 µl) and intrauterine HC-030031 (a selective transient receptor potential A1 receptor antagonist; 30 mg/kg, 0.2 ml) injected before the MO instillation attenuated the MO-induced colonic hypermotility and spinal NR2B phosphorylation. CONCLUSION: The comorbidity of gynecological/obstetrical and gastrointestinal problems is not coincidental but rather causal in nature, and clinicians should investigate for gynecological/urological diseases in the setting of bowel problems with no known pathological etiology.

Hybrid combination of small subxiphoid incision and thoracoscopic thymectomy for juvenile myasthenia gravis.

BACKGROUND/PURPOSE: Myasthenia gravis is an autoimmune disease that usually responds positively to treatment with thymectomy. Various approaches via video-assisted thoracic thymectomy as a substitute for conventional sternotomy have been reported. We reported a less invasive technique for thymectomy in pediatric groups. METHODS: Four adolescents with juvenile myasthenia gravis all underwent hybrid combination of small subxiphoid incision and thoracoscopic thymectomy at our institute. Clinical characteristics and surgical outcome were consecutively collected. RESULTS: In these 4 patients, 2 presented with Osserman class III and 2 with class IIb. The mean operative time was 180 minutes. There was no conversion to sternotomy, and there was only minimal blood loss. Follow-up duration was 3 to 64 months. Postoperatively, 1 patient had complete remission and 3 patients had improvement in clinical symptoms. CONCLUSION: Hybrid combination of small subxiphoid incision and thoracoscopic thymectomy may be an effective alternative with low surgical invasiveness for treating juvenile myasthenia gravis.

Endoscopic Treatment of Vesicoureteral Reflux in Children with Dextranomer/Hyaluronic Acid-A Single Surgeon's 6-Year Experience.

Endoscopic treatment for vesicoureteral reflux (VUR) has become an established alternative to long-term antibiotic prophylaxis and ureteral reimplantation. We present the outcome of endoscopic treatment with dextranomer/hyaluronic acid copolymer (Deflux) for VUR in children by a single surgeon at our institute from October 2003 to October 2009. We reviewed the cases of 150 patients (total 239 ureters), 56 girls (37%) and 94 boys (63%), with a mean age of 2.2 years and a median followup of 2.5 years (range 3-68 months). Among the 239 ureters treated, 67.4% (161/239) were cured with a single injection, and a second and third injection raised the cure rate to 86.6% (207/239) and 88.3% (211/239), respectively. None had postoperative ureteral obstruction.

Early repair of acquired tracheoesophageal fistula.

We report early direct repair of a cuff-related tracheoesophageal fistula in a 30-year-old alcoholic man with diabetic ketoacidosis who fell unconscious and was ventilated via an endotracheal tube. He was successfully weaned from the ventilator 1 week after the operation.