Novel SCN9A missense mutations contribute to congenital insensitivity to pain: Unexpected correlation between electrophysiological characterization and clinical phenotype.

Congenital insensitivity to pain (OMIM 243000) is an extremely rare disorder caused by loss-of-function mutations in SCN9A encoding Nav1.7. Although the SCN9A mutations and phenotypes of painlessness and anosmia/hyposmia in patients are previously well documented, the complex relationship between genotype and phenotype of congenital insensitivity to pain remains unclear. Here, we report a congenital insensitivity to pain patient with novel SCN9A mutations. Functional significance of novel SCN9A mutations was assessed in HEK293 cells expressing Nav1.7, the results showed that p.Arg99His significantly decreased current density and reduced total Nav1.7 protein levels, whereas p.Trp917Gly almost abolished Nav1.7 sodium current without affecting its protein expression. These revealed that mutations in Nav1.7 in this congenital insensitivity to pain patient still retained partial channel function, but the patient showed completely painlessness, the unexpected genotypic-phenotypic relationship of SCN9A mutations in our patient may challenge the previous findings "Nav1.7 total loss-of-function leads to painlessness." Additionally, these findings are helpful for understanding the critical amino acid for maintaining function of Nav1.7, thus contributing to the development of Nav1.7-targeted analgesics.

Increased Nav1.7 expression in the dorsal root ganglion contributes to pain hypersensitivity after plantar incision in rats.

Postoperative pain remains a complex problem that is difficult to manage in the clinical context, seriously affecting rehabilitation and the quality of life of patients after surgery. Nociceptors, of which the cell bodies are located in the dorsal root ganglion, are crucial for initiating and conducting the pain signal. The peripheral voltage-gated sodium channels, including Nav1.7, which is mainly expressed in the dorsal root ganglion, are key to understanding the mechanism underlying postoperative pain. Nav1.7, in particular, of which mutations in the encoding gene ( SCN9A) can determine whether pain occurs, has aroused most attention. Previous studies have shown that Nav1.7 in dorsal root ganglion is critical for the development of inflammatory pain and some neuropathic pain. However, the expression of Nav1.7 in the dorsal root ganglion after surgery and its role in postoperative pain hypersensitivity remain unclear. Therefore, in this study, in order to gain a better understanding of the role of dorsal root ganglion Nav1.7 in pain hypersensitivity following operation, we dynamically examined the pain-related behavior and expression of Nav1.7 in L4-L6 dorsal root ganglion before and after plantar incision in rats (an acute postoperative pain model). After plantar incision, the mechanical and thermal pain threshold decreased significantly, the cumulative pain score was increased significantly, meanwhile quantitative polymerase chain reaction and Western blotting results showed that expression of Nav1.7 in L4-L6 dorsal root ganglion was enhanced significantly. After pretreatment using SCN9A-RNAi-LV delivered via an intrathecal tube, immunohistochemistry showed that increased expression of Nav1.7 in L4-L6 dorsal root ganglion after plantar incision was inhibited, as also confirmed by quantitative polymerase chain reaction and Western blotting. Moreover, pain hypersensitivity was alleviated. These results suggested that Nav1.7 of L4-L6 dorsal root ganglion plays an important role in the development of pain hypersensitivity after plantar incision.

A variant in the SCN10A enhancer may affect human mechanical pain sensitivity.

Expression of Nav1.8, encoded by SCN10A, can affect pain transmission and thus mediate the human pain phenotype. In the current study, we assessed whether the variant rs6801957, located in the SCN10A enhancer region, may have the potential to affect human pain. Through dual-luciferase reporter assays in 293T cells, we found that the SCN10A enhancer A (Enh-A) increased the activity of the SCN10A promoter ( P < 0.05). Additionally, in a cohort of 309 healthy women, mutant rs6801957 A/A was found to have a significant association with decreased human experimental mechanical pain sensitivity ( P < 0.05). We then found that mutant genotype A/A suppressed the increased effect of Enh-A compared with wild-type G/G ( P < 0.05). The association between rs6801957 and human experimental mechanical pain sensitivity was further validated in a larger cohort of 1005 women ( P < 0.05). In conclusion, these results demonstrated that the variant rs6801957 and Enh-A may affect SCN10A gene expression and play an important role in human mechanical pain sensitivity.

Cerebral oxygen desaturation occurs frequently in patients with hypertension undergoing major abdominal surgery.

Hypertensive patients are more likely to experience latent cerebral ischemia causing regional cerebral oxygen saturation (rSO2) decrease during general anesthesia. The aim of this prospective observational study was to assess the incidence of decreased rSO2 in hypertensive patients undergoing major abdominal surgery and the perioperative factors affecting this change in rSO2. A total of 41 hypertensive patients were enrolled and stratified according to their hypertension as controlled and uncontrolled. The intraoperative rSO2 and physiological data were routinely collected. The Mini-Mental State Exam (MMSE) was used to test cognitive function before surgery and after 4 days. Cerebral desaturation was defined as a decrease in rSO2 of more than 20% of the baseline value. There were 20 patients (49%) suffering intraoperative cerebral desaturation classified into cerebral desaturation group (group D) and those 21 without intraoperative desaturation classified into normal group (group N). The area under the curve below 90 and 80% of baseline (AUCrSO2 <90% of baseline and AUCrSO2 <80% of baseline) was lower in patients of group N (2752.4 ± 1453.3 min% and 0.0 min%) than in patients of group D (6264.9 ± 1832.3 min% and 4486.5 ± 1664.9 min%, P < 0.001). Comparing the two groups, the number of uncontrolled hypertensive individuals in group D (12/20) was significantly more than group N (4/21) (P = 0.007). A significant correlation was observed between relative decrease in MAP and relative decrease in rSO2 (r2 = 0.495, P < 0.001). Moreover, nine patients (45%) in group D occurred early postoperative cognitive function decline were more than three patients (14.3%) in group N (P = 0.031). This pilot study showed a large proportion of hypertensive patient experienced cerebral desaturation during major abdominal surgery and uncontrolled hypertension predisposed to this desaturation. NCT02147275 (registered at http://www.clinicaltrials.gov ).

Efficacy and safety of patient-controlled intravenous analgesia after APS team standardized postoperative pain management: A 6-year experience of an acute pain service in 107802 Chinese patients.

There are few studies on the impact of postoperative pain management (such as Acute Pain Service, APS) on the prognosis of patients, especially the research on large samples, even less data on Chinese patients. It is reported that only 25.12 % of hospitals in China have established APS or similar teams, and less than 10 % of them are responsible for the whole process of postoperative analgesia services. Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology has established a professional APS team led by anesthesiologists (TJ-APS), and has a standardized workflow and management system. Based on the TJ-APS standardized postoperative pain management, the incidence and adverse effects of postoperative pain in different types of surgical patients were analyzed. In total, 107,802 patients receiving intravenous PCA from the Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology were selected between January 2016 and December 2021, which were under TJ-APS standardized postoperative analgesia process, postoperative analgesia strategy based on the principle of "low opioid, multimodal, specialization and individualization", as well as regular ward rounds and 24-h on call on-duty system. We assessed the incidence and adverse effects of postoperative pain in different types of surgical patients. Based on the TJ-APS standardized postoperative pain management, the incidence of poor postoperative analgesia in patients with intravenous PCA is significantly lower than that reported in the current literature (20 %), and mainly occurs in biliary-pancreatic surgery, extrahepatic surgery and gastrointestinal surgery. The overall incidence of adverse effects was 5.52 %, of which nausea and vomiting was the highest, especially among gynecological tumors and gynecological patients, which were 10.75 % and 8.68 % respectively, but both were lower than the level reported in the current literature (20 %). This APS multimodal management and analgesia process can provide reference and guidance for PCA management of postoperative acute pain.

Transcriptomics reveals the effects of NTRK1 on endoplasmic reticulum stress response-associated genes in human neuronal cell lines.

Background: NTRK1 gene, encoding TrkA, is essential for the nervous system and drives a variety of biological processes, including pain. Given the unsatisfied analgesic effects of some new drugs targeting NTRK1 in clinic, a deeper understanding for the mechanism of NTRK1 in neurons is crucial. Methods: We assessed the transcriptional responses in SH-SY5Y cells with NTRK1 overexpression using bioinformatics analysis. GO and KEGG analyses were performed, PPI networks were constructed, and the functional modules and top 10 genes were screened. Subsequently, hub genes were validated using RT-qPCR. Results: A total of 419 DEGs were identified, including 193 upregulated and 226 downregulated genes. GO showed that upregulated genes were mainly enriched in response to endoplasmic reticulum (ER) stress, protein folding in ER, etc., and downregulated genes were highly enriched in a series of cellular parts and cellular processes. KEGG showed DEGs were enriched in protein processing in ER and pathways associated with cell proliferation and migration. The finest module was dramatically enriched in the ER stress response-related biological process. The verified seven hub genes consisted of five upregulated genes (COL1A1, P4HB, HSPA5, THBS1, and XBP1) and two downregulated genes (CCND1 and COL3A1), and almost all were correlated with response to ER stress. Conclusion: Our data demonstrated that NTRK1 significantly influenced the gene transcription of ER stress response in SH-SY5Y cells. It indicated that ER stress response could contribute to various functions of NTRK1-dependent neurons, and therefore, ER stress response-associated genes need further study for neurological dysfunction implicated in NTRK1.

Pivotal role of the gut microbiota in congenital insensitivity to pain with anhidrosis.

BACKGROUND: Increasing evidence has shown that the occurrence and development of various human diseases are closely related to the gut microbiota. We compared the gut microbial communities of human subjects with congenital insensitivity to pain with anhidrosis (CIPA) and healthy controls (HCs) to assess whether fecal microbiota transplantation (FMT) into germ-free mice and mice in acute pain influenced the behaviors of the host. METHODS: We utilized 16 s rRNA analysis to compare the gut microbial communities of CIPA subjects and HCs and assessed whether FMT into germ-free mice and mice in acute pain influenced the behaviors of the host. RESULTS: In a 16 s RNA analysis, the CIPA group had significant decreases in the relative abundance of 11 bacteria, whereas 7 bacteria were significantly increased. In further animal experiments, the transplantation of fecal samples from CIPA patients to healthy mice significantly increased their scores on both the mechanical withdrawal test and the tail flick test; in an acute plantar incision model, scores were also significantly increased on the mechanical withdrawal test at 4 and 5 days after the operation. Moreover, pseudo-germ-free mice receiving fecal bacteria from patients with CIPA took significantly longer to escape and had a significantly longer path length on training days 1, 2, and 5 and also had fewer platform crossings and spent less time in the target quadrant in the probe trial. CONCLUSIONS: Our results suggest that the gut microbiota in CIPA subjects plays a key role in behaviors. Therapeutic strategies for improving the gut microbiota might alleviate CIPA symptoms.

Heterogeneity of clinical features and mutation analysis of NTRK1 in Han Chinese patients with congenital insensitivity to pain with anhidrosis.

PURPOSE: Congenital insensitivity to pain with anhidrosis (CIPA) is a rare inherited disorder whose core clinical features consist of no response to noxious stimuli and inability to sweat under any conditions. Our goal was to characterize the details of phenotypic and genotypic features in Chinese CIPA patients. PATIENTS AND METHODS: Personal data and clinical information were investigated by interview and physical examination. DNA was extracted from blood samples of patients and their available familial members and subjected to genetic analysis. RESULTS: A total of 41 Han Chinese CIPA patients from 35 unrelated families were recruited. The distribution of patients was mainly in the central and southern regions of China, with a male to female ratio of 3:1 and a mortality rate of 7.3%. Heterogeneity of clinical features, including pain insensitivity, temperature sensation, and complications, were cataloged. Interestingly, some patients had "visceral pain" sensation, and there was a significant difference in temperature perception and thermal pain between individuals. The incidence of bone and joint fractures was 49%. The characteristics of 19 mutations of NTRK1 in 41 patients, with five novel mutations, were identified. More than 63% of patients had the splice mutation, c.851-33 T>A, which strongly suggests that it may be a common pathogenic site in Han Chinese patients. CONCLUSION: Current findings expand our knowledge about the spectrum of phenotypic features and the racial characteristics of NTRK1 mutations of CIPA patients in the Han Chinese population.

Phenotypic and genotypic features of a pair of Chinese identical twins with congenital insensitivity to pain and anhidrosis: A case report.

RATIONALE: Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive genetic disorder characterized by insensitivity to noxious stimulus and the absence of sweating. Fractures and joint destruction are common complications, but detailed studies on mineral and skeletal homeostasis are not available. Mental retardation is often reported, but detailed observations during childhood are lacking. PATIENT CONCERNS: A pair of 46-month-old Chinese identical twin brothers was presented at our hospital. The brothers had the typical manifestations of insensitivity to noxious stimulus, inability to sweat, and recurrent episodes of unexplained fever. Fortunately, they did not present common complications such as self-mutilation, trauma, bruise, and repeated bone fractures. DIAGNOSES: Two novel compound heterozygous variants of NTRK1 (c.632T > A and c.1253_1254delTC) were identified. INTERVENTIONS: The patients were subjected to routine and specialist clinical examinations. Daily care and symptomatic treatment were given. OUTCOME: X-ray films of proband 2 showed a fracture in the first metatarsal. Decreased bone mineral density (BMD) and mild-to-moderate retardation of the Gesell developmental schedules (GDS), especially language and adaptability, were observed. Evaluation results for BMD and GDS in proband 2 were worse than those in his brother. LESSONS: The current findings expand our knowledge about the spectrum of phenotypic and genotypic features of CIPA, which will help facilitate future genotype-phenotype association studies. Daily care by parents promotes favorable outcomes in patients.

Associations between single-nucleotide polymorphisms in the NTRK1 gene and basal pain sensitivity in young Han Chinese women.

OBJECTIVES: The NTRK1 gene plays an important role in sensory and sympathetic neuronal survival. Mutations in this gene cause a rare hereditary disease known as congenital insensitivity to pain with anhidrosis. The aim of this study was to explore possible associations between single-nucleotide polymorphisms (SNPs) in NTRK1 and pain perception in a selected population. METHODS: A total of 309 healthy Han Chinese female undergraduates were recruited. Responses to quantitative sensory testing of pressure pain (dull, sharp, and acupuncture) were assessed, and genotyping of 13 tag-SNPs of NTRK1 was performed in the undergraduates recruited. Association analyses were performed via logistic regression analysis after adjusting for covariates such as age and body mass index. Promising associations were replicated in 197 patients scheduled to undergo gynecological surgery. RESULTS: The results showed that nine tag-SNPs of NTRK1 were significantly associated with pressure pain thresholds (P<0.05), leading to either hypersensitivity or hyposensitivity. More specifically, four tag-SNPs, rs1800880, rs6334, rs2644604 and rs943552, revealed a highly significant (P=0.008, 0.02, 0.01, 0.01, respectively) association with lower mechanical pain sensitivity of sharp pressure pain. Individuals who carried the haplotype CTCC were hyposensitive to sharp pressure pain compared with other haplotypes. CONCLUSION: These results suggest that polymorphisms in NTRK1 play an important role in pain sensitivity in young Han Chinese women.

Anesthetic management during adenotonsillectomy for twins with congenital insensitivity to pain with anhidrosis: two case reports.

BACKGROUND: Congenital insensitivity to pain with anhidrosis is a rare autosomal recessive disorder characterized by hyperpyrexia, anhidrosis, pain insensitivity, self-inflicted injuries, and intellectual disability. The anesthetic management of these patients is challenging owing to the high risk of perioperative complications resulting from their autonomic dysfunction, such as hyperthermia, hypotension, and bradycardia, which result from autonomic nervous system dysfunction. CASE PRESENTATION: Two 3-year-old Han Chinese identical male twins (weighing 13.5 kg and measuring 93 cm tall) were previously diagnosed as having congenital insensitivity to pain with anhidrosis based on clinical features and genetic screening. According to the presence of loud snoring and heavy breathing during sleep and neck radiograph findings, they were diagnosed as having tonsil and adenoid hypertrophy and needed adenotonsillectomy. Because of innate analgesia, some reports suggested that patients with congenital insensitivity to pain with anhidrosis do not require perioperative pain control. Accordingly, our patients did not receive opiates. We describe the general anesthetic management of these patients using sevoflurane and propofol, but without opiates, for adenotonsillectomy. Remarkable tachycardia and hypertension occurred during airway manipulation and when the surgical stimuli increased, and their temperatures increased from 36 °C and 36.8 °C to 37.8 °C and 38.5 °C, respectively. Patients with congenital insensitivity to pain with anhidrosis lack pain sensation, but they may have tactile hyperesthesia. Surgical noxious stimuli may therefore produce a stress response and unpleasant sensations, leading to hemodynamic fluctuation and temperature increase. CONCLUSIONS: On the basis of these findings, we suggest that careful intraoperative opiate titration may be justified to blunt the surgical stress response and promote hemodynamic and temperature stability in similar patients; we also recommend the preparation of warming and cooling devices and continuous temperature monitoring in these patients. Since anesthetic management of these patients is not simple, careful attention is required.

SCN11A variants may influence postoperative pain sensitivity after gynecological surgery in Chinese Han female patients.

Nav1.9, encoded by sodium voltage-gated channel alpha subunit 11 (SCN11A), is one of the main sodium channels involved in pain transmission. Dysfunction of Nav1.9 alters pain sensitivity, resulting in insensitivity to pain or familial episodic pain. Our purpose was to explore the effects of SCN11A single-nucleotide polymorphisms (SNPs) on postoperative pain sensitivity in Chinese Han female patients after gynecological surgery.Here, we combined the methods of tag SNPs and candidate SNPs. The associations between eleven SCN11A SNPs and basic pain sensitivity in female healthy volunteers were analyzed using the Plink software. The SNPs associated with basic pain sensitivity were termed positive SCN11A SNPs. The effect of these positive SNPs on postoperative pain sensitivity was explored in patients undergoing elective gynecological laparoscopic surgery and receiving postoperative patient-controlled analgesia (PCA). We assessed pain intensity using the numeric pain rating scale (NRS) and recorded PCA consumption.Our results suggested that 5 SNPs (rs33985936, rs13080116, rs11720988, rs11709492, and rs11720013) in 11 tag and candidate SNPs were associated with basic pain sensitivity (P < .05). No evident association was found between the 5 positive SNPs and NRS (P > .05). However, among these positive SNPs, the minor alleles of rs33985936 and rs13080116 were significantly associated with increased PCA consumption (P < .01).To our knowledge, this is the first study to report that SCN11A SNPs affect postoperative pain sensitivity in Chinese Han women after gynecological surgery. The SNP rs33985936 and rs13080116 may serve as novel predictors for postoperative pain.