[Analytical value of histological research and application of RNAscope technology in liver diseases]

RNAscope is a new generation of in situ hybridization technology and with the advantage of new probe design, it is now being gradually applied to a wide range of research fields, and its research scope is constantly expanding. Our country has large number of liver disease patients, so there is a great demand for histological testing and research evaluation based upon biological information. This technology has unique specificity and sensitivity in situ level, which makes up for the technical defects of immunohistochemistry and traditional in situ hybridization. Realizing the multiplicity and monomolecular level detection, the qualitative and quantitative analysis of nucleic acid level can be carried out in many aspects of the field of liver disease, and the visual evaluation can be achieved by combining it with tissue in situ to highlight the value of "gold standard". This article summarizes the recent year's application of RNAscope technology carried out in liver histology field.

[Research progress of the application of regional citrate anticoagulation in artificial liver to treat liver failure]

Liver failure is a rapidly progressive condition with a high mortality rate. Artificial liver treatment is one of the most important treatments for liver failure. In order to ensure the smooth functioning of in vitro circulation device, anticoagulants such as heparin or low-molecular-weight heparin are often used in clinical practice. However, it induces hemorrhage, thrombocytopenia and other adverse reactions, thereby threatening the life safety of liver failure patients. Regional citrate anticoagulation does not affect the coagulation mechanism in vivo, nor does it effects platelets, so in vitro circulating anticoagulants has become the first choice anticoagulant treatment method for continuous renal replacement therapy. Combined with the current research condition at home and abroad, the research progress of the application of regional citrate anticoagulation in artificial liver to treat liver failure is discussed, covering its principle content, application status and application prospect.

Hypomethylation of Notch1 DNA is associated with the occurrence of uveitis

Uveitis is a serious intra-ocular inflammatory disease that can lead to visual impairment even blindness worldwide. Notch signaling can regulate the differentiation of naive CD4⁺ T cells, influencing the development of uveitis. DNA methylation is closely related to the autoimmune diseases. In this study, we measured the Notch1 DNA methylation level, determined the Notch1 and related DNA methylases mRNA expression and evaluated the ratio of T helper type 17 regulatory T cell (Th17/T_reg ) in peripheral blood mononuclear cells (PBMCs) from uveitis patients and normal control subjects; we also tested the levels of relevant inflammatory cytokines in serum from the participants. Results indicated that compared with those in normal control individuals, the expression of ten-eleven translocation 2 (TET2) and Notch1 mRNA is elevated in uveitis patients, whereas the methylation level in Notch1 DNA promotor region [-842 ~ -646 base pairs (bp)] is down-regulated, and is unrelated to anatomical location. Moreover, the Th17/T_reg ratio is up-regulated in PBMCs from uveitis patients, accompanied by the elevated levels of proinflammatory cytokines [e.g. interleukin (IL)-2, IL-6, IL-17 and interferon (IFN)-γ] in serum from uveitis patients. These findings suggest that the over-expression of TET2 DNA demethylase may lead to hypomethylation of Notch1, activate the Notch1 signaling, induce naive CD4⁺ T cells to differentiate theTh17 subset and thus disturb the balance of the Th17/T_reg ratio in uveitis patients. Overall, hypomethylation of Notch1 DNA is closely associated with the occurrence of uveitis. Our study preliminarily reveals the underlying mechanism for the occurrence of uveitis related to the hypomethylation of Notch1 DNA, providing a novel therapeutic strategy against uveitis in clinical practice.

Grazing mediates soil microbial activity and litter decomposition in salt marshes

Salt marshes contribute to climate change mitigation because of their great capacity to store organic matter (OM) in soils. Most of the research regarding OM turnover in salt marshes in times of global change focuses on effects of rising temperature and accelerated sea-level rise, while effects of land-use change have gained little attention. The present work investigates the mechanisms by which livestock grazing can affect OM decomposition in salt marsh soils. In a grazing exclusion experiment at the mouth of the Yangtze estuary, China, we assessed soil microbial exo-enzyme activity (EEA) to gain insight into the microbial carbon (C) and nitrogen (N) demand. Additionally, we studied the decomposition of plant litter in soil using the Tea Bag Index (TBI), a widely used standardized litter bag assay to fingerprint soil decomposition dynamics. Based on EEAs, grazing markedly reduced microbial C acquisition, whereas microbial N acquisition was strongly increased. These opposing grazing effects were also evident in the decomposition of standardized plant litter: The decomposition rate constant (k) and the stabilization (S) of litter were not inversely related, as would be expected, but instead both were reduced by livestock grazing. Our data suggest that gazing effects on EEAs and litter decomposition can just partly be explained by grazing-driven soil compaction and resulting lower oxygen availability, which has previously been hypothesized as a main pathway by which grazing can reduce microbial activity in wetland soils. Instead, grazing effects on microbial nutrient demand occurs to be an at least equally important control on soil decomposition processes.

FRI0508 MALIGNANCY AND IGG4-RELATED DISEASE: THE INCIDENCE, RELATED FACTORS AND PROGNOSIS FROM A PROSPECTIVE COHORT STUDY IN CHINA

Background:

The association between IgG4-related disease (IgG4-RD) and malignancies is unclear. No epidemiological data for malignancies in Chinese IgG4-RD patients is available. It is also important to know the risk factors and prognosis for IgG4-RD patients harboring malignancies.

Objectives:

To investigate the incidence, related factors and prognosis of IgG4-related disease (IgG4-RD) with malignancies in the Chinese cohort.

Table 1.

Baseline characteristic of IgG4-RD patients with malignancy

PatientSexAgeAge at diagnosis of IgG4-RDAge at diagnosis of malignancySerum IgG4(g/L)Organs involvements of IgG4-RD(*Organ with biopsy)Sites of malignancyP1F5958541499Parotid gland*, salivary glandBreast cancerP2M74666810402Pancreas, bile duct, retroperitoneal fibrosis, kidney, prostate, lymph nodesRectal cancerP3M4642402630Lacrimal gland, parotid glandLipoblastomaP4M7068645780Pancreas, bile duct, lung, prostate, lymph nodesThyroid carcinomaP5F62616111600Pancreas, bile duct, salivary gland*, periaortitis, lymph nodes, pituitaryThyroid carcinomaP6M7268683490Pancreas, bile duct, lymph nodesRectal cancerP7M6058582410Pancreas, bile duct, lymph nodesRenal cancerP8M6863683520Pancreas, bile duct, retroperitoneal fibrosis, lung, kidney, artery, lymph nodesRectal cancerP9M36303512400Pancreas, bile ductSkin cancerP10M52495210000Pancreas, parotid gland*, lacrimal gland, lung, prostate, lymph nodesThyroid carcinomaP11F70686917300Parotid gland, lacrimal gland, salivary gland, sinusLung cancerP12M82797958000Pancreas, lacrimal gland*Colon cancerP13F50494514300Uterus*, ovaryOvarian carcinomaP14F52465010000Parotid gland*, lacrimal glandBreast cancerP15F60555712500Pancreas, parotid gland, lacrimal gland, lymph nodes, sinusLymphomaP16M4237407490Lung*, lymph nodesRenal cancerP17M716869415Pancreas*, bile ductProstate cancerTable 2.

Related factors for malignancies in patients with IgG4-RD

VariablesUnivariate analysisMultivariate analysisUnivariate OR (95%Cl)P-valueMultivariate OR (95%Cl)P-valueHead and Neck involvement0.304 (0.097- 0.952)0.0410.604 (0.152-2.401)0.474Autoimmune pancreatitis5.359 (1.651-17.393)0.0056.230 (1.559-24.907)0.010Eosinophilia0.117 (0.014-0.966)0.0460.094 (0.010-0.883)0.039Figure 1.

Standardized incidence ratios of malignancies in patients with IgG4-RD from different studies.

Methods:

We prospectively analyzed the IgG4-RD patients recruited in Peking Union Medical College Hospital from January 2011 to August 2018 and identified patients diagnosed with IgG4-RD complicating malignancies. Data regarding demographics, clinical features, treatment and prognosis of IgG4-RD patients complicating malignancies were collected and compared to those of age- and sex-matched controls.

Results:

Among the 587 Chinese patients with IgG4-RD, 17 malignancies were identified. Ten of them developed malignancy after the diagnosis of IgG4-RD, given a standard incidence ratio (SIR) of 2.78 (95%CI 1.33-5.12). Multivariate logistic analysis indicated that autoimmune pancreatitis (OR= 6.230, 95%CI 1.559-24.907, p=0.010) was positively associated with malignancy, whereas eosinophilia (OR= 0.094, 95%CI 0.010-0.883, p=0.039) was negatively related with malignancies. During a median follow-up period of 61.4±26.4 months, all patients with IgG4-RD and malignancies survived.

Conclusion:

An increased incidence of malignancy was found in Chinese IgG4-RD cohort. Autoimmune pancreatitis is a potential risk factor, whereas eosinophilia is a possible protective factor for complicating malignancies.

References:

[1] Wallace, Z. S.,et al. Association of IgG4-Related Disease With History of Malignancy. Arthritis Rheumatol 68, 2283–2289 (2016).

[2] Hirano, K. et al. Incidence of malignancies in patients with IgG4-related disease. Intern. Med. 53, 171–176 (2014).

Disclosure of Interests:

None declared

Clinical potential of ctDNA-based TMB in small cell lung cancer recieving chemoradiotherapy

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Background: Small cell lung cancer (SCLC) is an aggressive tumor with poor prognosis. Chemotherapy and / or radiotherapy is the main choice of SCLC treatment. Circulating tumor DNA (ctDNA) has received substantial attention in recent years owing to the potential of patient stratification and monitoring. Here, we assessed the value of prediction and prognosis using ctDNA in SCLC. Methods: SCLC patients (pts) with limited-stage disease (LD) receiving chemoradiotherapy and extensive-stage disease (ED) receiving chemotherapy were enrolled. Baseline plasma samples were collected for NGS using a 1021-gene-panel. Mutational features and blood-based tumor mutation burden (bTMB) were analyzed using ctDNA. pyClone software was used to cluster the mutations. The mutations in the cluster with the highest cancer cell fraction (CCF) were defined as clonal mutations. Progression-free survival (PFS) was followed. Results: 58 SCLC pts (35 LD and 23 ED) and 58 plasma samples were enrolled. Smoking pts accounted for 84% (49/58). In all samples, recurrent genes were TP53 (86%), RB1 (57%), LRP1B (34%), CREBBP (26%), and MLL3 (22%). The median of bTMB and clone count were 7.9 [0-26] and 7 [0-25]. Significant higher bTMB and clone count were observed in ED pts compared with LD (Mann Whitney test, p = 0.019 and p = 0.041, respectively). Mutated CREBBP (10/23 ED versus 5/35 LD) was enriched in ED (Fisher exact test, p = 0.017 and OR = 0.223). Mutations in NOTCH signaling pathway were enriched in ED (l6/23 ED versus 13/35 LD, p = 0.031, OR = 0.265). In LD group, there were trend toward prolonged PFS in pts with higher bTMB(p = 0.065), and pts with higher clonal bTMB (cbTMB) exhibited significant longer PFS (p = 0.016, HR 0.37, 95% CI [0.12-1.11]). Patients with alteration in PIK3CA showed shorter PFS than wild type (p < 0.001, HR 0.11, 95% CI [0-2.86]). There were no significant difference in median PFS in LD stage pts with any detectable pathway alterations. Whereas, LD pts whose ctDNA contained RTK-RAS signaling pathway alterations exhibited shorter PFS than pts without those alterations (p = 0.135). In ED pts, NOTCH1 gene wild type displayed longer PFS than mutant type (p = 0.036, HR 0.38, 95% CI [0.1-1.53]). There were no difference in PFS between pts with higher and lower bTMB and cbTMB. Conclusions: ctDNA can characterize the mutational feature of SCLC. There are differences in the molecular characteristics between ED and LD pts. Clonal bTMB is a potential prognostic biomarker for LD SCLC chemoradiotherapy. The prognostic marker of ED chemotherapy is different from LD.

[Pre- and post-treatment changes of gingvitis-associated peptidomic profiles in the saliva and gingival crevicular fluid by mass spectrometry]

Objective: To explore peptidomic changes of peptides in saliva and gingival crevicular fluid (GCF) before and after treatment of gingivitis. Methods: From January 2017 to September 2017, seventeen participants at the age of 24-62 (6 males and 11 females) at Department of Preventive Dentistry, Peking University School and Hospital of Stomatology with gingivitis were recruited in the present study. Their clinical parameters were measured and recorded. Saliva and GCF samples were collected from each of the participants at the baseline and 7 days after ultrasonic supragingival scaling, respectively. Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) was employed to detect the changes of peptidomic profiles, while ano-liquid chromatography-electrospray ionization-tandem mass spectrometry (nano-LC/ESI-MS/MS) was performed to identify the possible proteins from which the peptides might derive. Results: Initially, four peptide peaks [mass-to-charge ratio (m/z) values: 1 030.6, 1 043.4, 1 053.4 and 1 064.6] were screened out exhibiting a decreasing trend after treatment (P<0.05). Besides, five peptide peaks from gingival crevicular fluid (P<0.05) exhibited differential expression, among which 1 055.5 and 1 168.3 demonstrating a decrease after treatment, while 3 363.7, 3 480.9 and 3 489.5 increased overtime. Certain positive correlations were detected between some peptides and clinical parameters. Principle component analysis using the above mentioned peptide peaks showed a distinct distribution before and after treatment and peptides from GCF showed a slightly better capacity to discriminate patients before and after treatment. The peptides with m/z values of 1 055.5 in GCF and 1 064.6 in saliva were identified to be segments of serum albumin and complement C3, respectively. Conclusions: Several differentially expressed peptides were detected in saliva and GCF by MALDI-TOF MS, exhibiting the potentiality to act as biomarkers in gingivitis patients.

MicroRNA-15a-5p down-regulation inhibits cervical cancer by targeting TP53INP1 in vitro

OBJECTIVE

An increasing number of reports have shown that microRNAs (miRNAs) play a vital role in the occurrence and development of cancer by acting as tumor inhibitors or oncogenes. The purpose of this research was to explore whether the expression level of microRNA-15a-5p (miR-15a-5p) was related to TP53 regulated inhibitor of apoptosis 1 (TP53INP1) in cervical cancer, and to explore the role of miR-15a-5p in cervical cancer in vitro.

PATIENTS AND METHODS

Human cervical cancer tissues and adjacent normal tissues were obtained from 30 cervical cancer patients. Firstly, we carried out the quantitative Real Time-PCR (qRT-PCR) assay to evaluate the level of miR-15a-5p in cervical cancer tissues and cell lines. The TargetScan and the Dual-Luciferase Reporter Assay were used to confirm the relationship between TP53INP1 and miR-15a-5p. Besides, the Cell Counting Kit-8 (CCK-8) and the flow cytometry analysis were performed to detect the effect of miR-15a-5p on cell proliferation and apoptosis in cervical cancer cells.

RESULTS

Our results showed that the expression of miR-15a-5p was enhanced in cervical cancer tissues and cells lines. The data from the Dual-Luciferase Reporter Assay demonstrated that TP53INP1 was a direct target of miR-15a-5p. We also found that TP53INP1 was down-regulated in the cervical cancer tissues and cell lines compared with the adjacent normal tissues and normal cervical cells. Besides, the down-regulation of miR-15a-5p depressed cervical cancer cell proliferation and enhanced cell apoptosis. Our results clearly suggested that the down-regulation of TP53INP1 successfully impaired the tumor-inhibition effects of miR-15a-5p inhibitor in cervical cancer cells.

CONCLUSIONS

Our findings indicated that miR-15a-5p functioned as a tumor-promoting gene in cervical cancer by directly targeting TP53INP1, indicating that miR-15a-5p might be a potential treatment target for cervical cancer patients.

[Research progress of hepatitis B and C virus co-infection]

Hepatitis B virus (HBV)/hepatitis C virus (HCV) co-infection shares the same transmission routes, and thereby it is not rare in regions where the prevalence of HBV and HCV is high. However, the co-infection rates of HBV/HCV reported in different regions of the world are relatively dissimilar, and the co-infection rates of HBV/HCV in the population are unidentified due to the presence of silent HBV infection. Thus, the phenomenon of underestimation exists. HCV may have an inhibitory effect on HBV replication when HBV/HCV is co-infected, and the effect of HBV on HCV replication remains to be certain by more studies. Furthermore, the mechanism of interaction may include the direct effect of viral proteins and the indirect effect of immune mediated host response. HBV/HCV co-infection can cause more serious chronic liver diseases and cirrhosis, and can increase the risk of liver cancer. The efficacy of peginterferon plus ribavirin in patients with HBV/HCV co-infection is same as HCV monotherapy. There are few studies on the efficacy of direct-acting antiviral drugs. Patients with HBV/HCV co-infection have the risk of HBV reactivation regardless of anti-HCV treatment with peginterferon plus ribavirin or direct-acting antiviral drugs, but the probability of HBV reactivation and how to assess and prevent it needs more studies to interpret.

Impact of sites versus number of metastases on survival of patients with organ metastasis from newly diagnosed cervical cancer

Objective

The aim of this study was to investigate the potential associations of the sites and the number of specific metastases with survival in patients newly diagnosed with cervical cancer.

Methods

Medical records of patients with organ metastases of newly diagnosed cervical cancer at Zhejiang Cancer Hospital from October 2006 to December 2016 were reviewed retrospectively. Survival times were compared using the Kaplan-Meier method. Variables associated with survival were identified using univariate and multivariate Cox proportional hazards models.

Results

A total of 99 patients with newly diagnosed organ metastatic cervical cancer were identified. Median follow-up was 11.6 months (range, 0.5–114.7 months). Median overall survival (OS) time was 11.7 months from diagnosis, with 1, 2, and 5-year OS rates of 48.2%, 22.8%, and 12.6%, respectively. The most common site of organ metastasis was bone (36.8%), followed by lung (32.8%) and liver (24%). In univariate analysis, OS rates were better for bone metastasis than visceral metastasis (P=0.013), oligometastasis than non-oligometastasis (P=0.003) and single organ metastasis than multiple organ metastases (P=0.016), while that for liver metastasis was poorer than non-liver metastases (P<0.001). In multivariate analysis, liver metastasis (hazard ratio [HR] =4.02; 95% confidence interval [CI], 1.15-14.05, P=0.029) was significantly and independently related to poor overall survival.

Conclusion

Our data revealed the site of metastasis is associated with overall survival of patients with newly diagnosed organ metastatic cervical cancer, with liver metastasis signifying particularly poor overall survival. Individualized treatments should be administered to patients depending on the specific metastatic sites.

Wheat-dependent exercise-induced anaphylaxis in Chinese people: a clinical research on 33 cases with antigenic analysis of wheat proteins

BACKGROUND

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a severe allergic condition in which wheat ingestion together followed by physical exercise induces anaphylaxis. For patients with WDEIA, omega-5 gliadin is considered to be one of the major allergens.

AIM

To analyse the clinical features and allergen spectrum of WDEIA and to investigate the relationship between WDEIA and serum levels of platelet-activating factor (PAF), interleukin (IL)-9 and IL-33.

METHODS

Medical histories and conditions of WDEIA cases were collected and summarized, with allergen tests of wheat proteins measured at the same visit. Of the 33 patients enrolled, 13 also had serum levels of PAF, IL-9 and IL-33 measured. The healthy control (HC) group consisted of 13 healthy individuals, who also underwent both the wheat-protein allergen tests and the inflammatory-mediator tests.

RESULTS

All patients experienced severe allergic reaction during exercise after wheat ingestion. Manifestations of WDEIA included facial oedema, generalized urticaria and respiratory symptoms. Unconsciousness was also observed in 21 cases. In the patient group, 57.6% were confirmed as hypersensitive to glyceraldehyde-3-phosphate dehydrogenase (GAPDH), while 54.5% were allergic to omega-5 gliadin. PAF concentration was significantly higher in patients with WDEIA compared with HCs, whereas there was no significant difference in IL-9 or IL-33 between the two groups.

CONCLUSIONS

WDEIA is a rare type of anaphylaxis. GAPDH and omega-5 gliadin may be the most common allergy-causing wheat proteins for Chinese people. PAF may be associated with the onset and development of WDEIA.

Urinary mitochondrial DNA copy number identifies renal mitochondrial injury in renovascular hypertensive patients undergoing renal revascularization: A Pilot Study

AIMS

Patients with renovascular hypertension (RVH) exhibit elevated urinary mtDNA copy numbers, considered to constitute surrogate markers of renal mitochondrial injury. The modest success of percutaneous transluminal renal angioplasty (PTRA) in restoring renal function in RVH has been postulated to be partly attributable to acute reperfusion injury. We hypothesized that mitoprotection during revascularization would ameliorate PTRA-induced renal mitochondrial injury, reflected in elevated urinary mtDNA copy numbers and improve blood pressure and functional outcomes 3 months later.

METHODS

We prospectively measured urinary copy number of the mtDNA genes COX3 and ND1 using qPCR in RVH patients before and 24 hrs after PTRA, performed during IV infusion of vehicle (n = 8) or the mitoprotective drug elamipretide (ELAM, 0.05 mg/kg/h, n = 6). Five healthy volunteers (HV) served as controls. Urinary mtDNA levels were also assessed in RVH and normal pigs (n = 7 each), in which renal mitochondrial structure and density were studied ex-vivo.

RESULTS

Baseline urinary mtDNA levels were elevated in all RVH patients vs HV and directly correlated with serum creatinine levels. An increase in urinary mtDNA 24 hours after PTRA was blunted in PTRA+ELAM vs PTRA+Placebo. Furthermore, 3-months after PTRA, systolic blood pressure decreased and estimated glomerular filtration rate increased only in ELAM-treated subjects. In RVH pigs, mitochondrial damage was observed using electron microscopy in tubular cells and elevated urinary mtDNA levels correlated inversely with renal mitochondrial density.

CONCLUSIONS

PTRA leads to an acute rise in urinary mtDNA, reflecting renal mitochondrial injury that in turn inhibits renal recovery. Mitoprotection might minimize PTRA-associated mitochondrial injury and improve renal outcomes after revascularization.

Choice of immobilization of stereotactic body radiotherapy in lung tumor patient by BMI

BACKGROUND

An accurate, reproducible, and comfortable immobilization device is essential for stereotactic radiotherapy (SBRT) in patients with lung cancer. This study compared thermoplastic masks (TMP) and vacuum cushion (VCS) system to assess the differences in interfraction and intrafraction setup accuracy and the impact of body mass index (BMI) with respect to the immobilization choice.

METHODS

This retrospective study was conducted on patients treated with lung SBRT between 2012 and 2015 at the Zhejiang cancer hospital. The treatment setup accuracy was analyzed in 121 patients. A total of 687 cone beam computed tomography (CBCT) scans before treatment and 126 scans after treatment were recorded to determine the uncertainties, and plan target volume margins. Data were further stratified and analyzed by immobilization methods and patients' BMI. The t-test (Welch) was used to assess the differences between the two immobilization systems when stratified by the patients' BMI.

RESULTS

For patients with BMI ≥ 24, the mean displacements for the TMP and VCS systems were 1.4 ± 1.2 vs. 2.4 ± 2.0 mm at medial-lateral (ML) direction (p < 0.001); 2.0 ± 1.9 vs. 2.0 ± 1.9 mm at cranial-caudal (CC) direction (p = 0.917); and 2.4 ± 1.4 vs. 2.6 ± 2.1 mm at anterior-posterior (AP) direction, (p = 0.546). The rate of acceptable errors increased dramatically when immobilized by TMP. In the case of patients with BMI < 24, the mean displacements for the TMP and VCS systems were 1.8 ± 1.4 vs. 2.1 ± 1.8 mm at ML direction (p = 0.098); 2.9 ± 2.3 vs. 2.2 ± 2.2 mm at CC direction (p = 0.001); and 1.8 ± 1.8 vs. 2.3 ± 2.0 mm at CC direction, (p = 0.006). The proportion of acceptable errors increased after immobilization by VCS. No difference was detected in the intrafraction setup error by different immobilization methods.

CONCLUSIONS

The immobilization choice of SBRT for lung tumors depends on the BMI of the patients. For patients with BMI ≥ 24, TMP offers a better reproducibility with significantly less interfractional setup displacement than VCS, resulting in fewer CBCT scans. However, VCS may be preferred over TMP for the patients with BMI < 24. Therefore, an optimal immobilization system needs to be considered in different BMI groups for lung SBRT.

A Novel SCN9A Mutation (F826Y) in Primary Erythromelalgia Alters the Excitability of Nav1.7

BACKGROUND

Primary erythromelalgia (PE) is a dominant inherited disorder characterized by recurrent pain, redness, and warmth of the extremities that is caused by gain-of-function mutations in Nav1.7 encoding gene SCN9A. Most of the PE-causing mutations of Nav1.7 have been shown to be able to render Nav1.7-expressing cells hyperexcitable, however in most PE cases the symptoms are refractory to treatment with sodium channel blockers and the mechanism underlying the intractability has not been clearly clarified.

OBJECTIVE

To identify the mutation of SCN9A in a Chinese Han family with typical symptoms of PE and study the electrophysiological effect of the identified mutation.

METHODS

A Chinese Han family with typical symptoms of PE was collected and the proband's response to treatment was recorded. All the exons and flanking intronic sequences of SCN9A were amplified with PCR and sequenced. Several online programs were used to predict the damaging effect of variants. The functional effect of variants was studied by voltage-clamp analysis in CHO-K1 cells.

RESULTS

The PE symptoms of the proband are refractory to all kinds of reported medications. Sequence analysis of SCN9A showed that a novel c.2477T>A (p. F826Y) mutation co-segregated with the disease phenotype. Several online programs predicted that the F826Y mutation has a deleterious effect on the gene product. Voltage-clamp analysis showed that while compared with the wild-type channel, activation of the F826Y mutant channel was shifted by 7.7 mV in a hyperpolarizing direction, whereas steadystate inactivation was shifted by 4.3 mV in a depolarizing direction.

CONCLUSION

A novel disease-causing SCN9A Mutation (F826Y) was identified in a Chinese family with typical PE symptoms refractory to treatment. F826Y of Nav1.7 could render DRG neurons hyperexcitable, contributing to the pathogenesis of PE.