Mediation role of DNA methylation in association between handgrip strength and cognitive function in monozygotic twins

Handgrip strength is a crucial indicator to monitor the change of cognitive function over time, but its mechanism still needs to be further explored. We sampled 59 monozygotic twin pairs to explore the potential mediating effect of DNA methylation (DNAm) on the association between handgrip strength and cognitive function. The initial step was the implementation of an epigenome-wide association analysis (EWAS) in the study participants, with the aim of identifying DNAm variations that are associated with handgrip strength. Following that, we conducted an assessment of the mediated effect of DNAm by the use of mediation analysis. In order to do an ontology enrichment study for CpGs, the GREAT program was used. There was a significant positive association between handgrip strength and cognitive function (β = 0.194, P < 0.001). The association between handgrip strength and DNAm of 124 CpGs was found to be statistically significant at a significance level of P < 1 × 10-4. Fifteen differentially methylated regions (DMRs) related to handgrip strength were found in genes such as SNTG2, KLB, CDH11, and PANX2. Of the 124 CpGs, 4 within KRBA1, and TRAK1 mediated the association between handgrip strength and cognitive function: each 1 kg increase in handgrip strength was associated with a potential decrease of 0.050 points in cognitive function scores, mediated by modifications in DNAm. The parallel mediating effect of these 4 CpGs was -0.081. The presence of DNAm variation associated with handgrip strength may play a mediated role in the association between handgrip strength and cognitive function.

Epigenome-wide association study identifies DNA methylation loci associated with handgrip strength in Chinese monozygotic twins

Background: The decline in muscle strength and function with aging is well recognized, but remains poorly characterized at the molecular level. Here, we report the epigenetic relationship between genome-wide DNA methylation and handgrip strength (HGS) among Chinese monozygotic (MZ) twins. Methods: DNA methylation (DNAm) profiling was conducted in whole blood samples through Reduced Representation Bisulfite Sequencing method. Generalized estimating equation was applied to regress the DNAm of each CpG with HGS. The Genomic Regions Enrichment of Annotations Tool was used to perform enrichment analysis. Differentially methylated regions (DMRs) were detected using comb-p. Causal inference was performed using Inference about Causation through Examination of Familial Confounding method. Finally, we validated candidate CpGs in community residents. Results: We identified 25 CpGs reaching genome-wide significance level. These CpGs located in 9 genes, especially FBLN1, RXRA, and ABHD14B. Many enriched terms highlighted calcium channels, neuromuscular junctions, and skeletal muscle organ development. We identified 21 DMRs of HGS, with several DMRs within FBLN1, SLC30A8, CST3, and SOCS3. Causal inference indicated that the DNAm of 16 top CpGs within FBLN1, RXRA, ABHD14B, MFSD6, and TYW1B might influence HGS, while HGS influenced DNAm at two CpGs within FBLN1 and RXRA. In validation analysis, methylation levels of six CpGs mapped to FLBN1 and one CpG mapped to ABHD14B were negatively associated with HGS weakness in community population. Conclusion: Our study identified multiple DNAm variants potentially related to HGS, especially CpGs within FBLN1 and ABHD14B. These findings provide new clues to the epigenetic modification underlying muscle strength decline.

Co-methylation analyses identify CpGs associated with lipid traits in Chinese discordant monozygotic twins

To control genetic background and early life milieu in genome-wide DNA methylation analysis for blood lipids, we recruited Chinese discordant monozygotic twins to explore the relationships between DNA methylations and total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG). 132 monozygotic (MZ) twins were included with discordant lipid levels and completed data. A linear mixed model was conducted in Epigenome-wide association study (EWAS). Generalized estimating equation model was for gene expression analysis. We conducted Weighted correlation network analysis (WGCNA) to build co-methylated interconnected network. Additional Qingdao citizens were recruited for validation. Inference about Causation through Examination of Familial Confounding (ICE FALCON) was used to infer the possible direction of these relationships. A total of 476 top CpGs reached suggestively significant level (P < 10-4), of which, 192 CpGs were significantly associated with TG (FDR < 0.05). They were used to build interconnected network and highlight crucial genes from WGCNA. Finally, four CpGs in GATA4 were validated as risk factors for TC; six CpGs at ITFG2-AS1 were negatively associated with TG; two CpGs in PLXND1 played protective roles in HDL-C. ICE FALCON indicated abnormal TC was regarded as the consequence of DNA methylation in CpGs at GATA4, rather than vice versa. Four CpGs in ITFG2-AS1 were both causes and consequences of modified TG levels. Our results indicated that DNA methylation levels of 12 CpGs in GATA4, ITFG2-AS1, and PLXND1 were relevant to TC, TG, and HDL-C, respectively, which might provide new epigenetic insights into potential clinical treatment of dyslipidemia.

[A sampling survey of intraoperative facial nerve monitoring in China]

Objective: This study aims to investigate the current application and the level of knowledge of intraoperative facial nerve monitoring among medical staff in China. Methods: A comprehensive online questionnaire was conducted among medical professionals across different regions in China from October 2022 to February 2023. The survey exclusively targeted departments specializing in otolaryngology, head and neck surgery, neurosurgery, and oral and maxillofacial surgery. The questionnaire covered various aspects including general information, intraoperative facial nerve monitoring practices, training history, indications for monitoring, parameters used during monitoring procedures, as well as factors influencing its implementation. Results: A total of 417 participants from 31 provincial, municipal, and autonomous regions were included. Intraoperative facial nerve monitoring was found to be implemented in 227 (54.4%,227/417) repondents of 53 institutions (24.9%, 53/213). The top three indications for implementing this technique were acoustic neuroma, parotid gland surgery, and modified middle ear surgery (mastoidectomy). Herein 81.1%(184/227) medical staff involved in intraoperative facial nerve monitoring had received relevant training, 57.3%(130/227)-92.1%(209/227) reported a lack of clear description regarding recording thresholds, stimulation currents/frequencies/wave widths. Conclusion: The majority of the institutions surveyed have not yet adopted intraoperative facial nerve monitoring. Furthermore, significant gaps concerning the procedure exist. It is imperative to establish standards or guidelines to promote its better development and application.

[Bioinformatics analysis of the RNA binding protein DDX39 of Toxoplasma gondii]

OBJECTIVE

To analyze the RNA binding protein of Toxoplasma gondii (TgDDX39) using bioinformatics technology, and to evaluate the immunogenicity of TgDDX39, so as to provide insights into development of toxoplasmosis vaccines.

METHODS

The amino acid sequences of TgDDX39 were retrieved from the ToxoDB database, and the physicochemical properties, transmembrane structure domain, signal peptide sites, post-translational modification sites, coils, secondary and tertiary structures, hydrophobicity, and antigenic epitopes of the TgDDX39 protein were predicted using online bioinformatics tools, incluiding ProtParam, TMHMM 2.0, SignalP 5.0, NetPhos 3.1, COILS, SOPMA, Phyre2, ProtScale, ABCpred, SYFPEITHI and DNA-STAR.

RESULTS

TgDDX39 protein was predicted to be an unstable hydrophilic protein with the molecular formula of C2173H3458N598O661S18, which contained 434 amino acids and had an estimated molecular weight of 49.1 kDa and a theoretical isoelectric point of 5.55. The protein was predicted to have an extremely low possibility of signal peptides, without transmembrane regions, and contain 27 phosphorylation sites. The β turn and random coils accounted for 39.63% of the secondary structure of the TgDDX39 protein, and a coiled helix tended to produce in one site. In addition, the TgDDX39 protein contained multiple B and T cell antigenic epitopes.

CONCLUSIONS

Bioinformatics analyses predict that TgDDX39 protein has high immunogenicity and contains multiple antigenic epitopes. TgDDX39 protein is a potential candidate antigen for vaccine development.

Efficacy and Safety of Local Radiotherapy Combined with Chemotherapy ± Bevacizumab in the Treatment of Patients with Advanced and Recurrent Metastatic Cervical Cancer

PURPOSE/OBJECTIVE(S)

To observe the efficacy and safety of local radiotherapy combined with chemotherapy ± bevacizumab in the treatment of patients with advanced or recurrent metastatic cervical cancer.

MATERIALS/METHODS

A total of 53 patients with advanced and recurrent metastatic cervical cancer who had received local radiotherapy combined with chemotherapy ± bevacizumab in Affiliated Cancer Hospital of Guizhou Medical University from July 2018 to October 2021 were collected. The recurrence types included 21 patients of pelvic recurrence, 7 patients of distant metastasis, 14 patients of complex pelvic recurrence and distant metastasis, and 11 patients of advanced stage (initial diagnosis stage IVB). The primary endpoints were objective response rate (ORR) and disease control rate (DCR). The secondary endpoints were progression-free survival (PFS), overall survival (OS) and incidence of adverse reactions.

RESULTS

(1) Complete response (CR) was achieved in 4 patients (7.5%), partial response (PR) in 34 patients (64.2%), stable disease (SD) in 12 patients (22.6%), and disease progression (PD) in 3 patients (5.7%), ORR was 71.7%, DCR was 94.3%. (2) The follow-up time was 5.3 to 45.7 months, the median OS was 29.3 months, the median PFS was 15.7 months, the one-year and two-year OS were 83.0% and 59.2%, and the 1-year and two-year PFS were 62.2% and 34.4%. (3) Recurrence type, tumor size at the time of recurrence, and efficacy after radiotherapy were significant factors for PFS and OS rates in multivariate analysis. (4) The main adverse reactions were myelosuppression, gastrointestinal reaction and urinary reaction. Grade IV leukopenia occurred at 13.2%, grade IV neutropenia at 11.3%, grade IV thrombocytopenia at 15.1%, and grade IV anemia at 5.7%, all of which were tolerable. The gastrointestinal and urinary reactions were mainly grade I-II, and the incidence of vesical or rectovaginal fistulas was about 7.5% (2 patients had rectovaginal fistulas and 2 patients had vesto-vaginal fistulas).

CONCLUSION

Local radiotherapy combined with chemotherapy ± bevacizumab can improve the efficacy and survival of patients with advanced and recurrent metastatic cervical cancer. Adverse reactions are tolerable and may provide survival benefits in these patients.

Effect of Concurrent Chemoradiotherapy on Regulatory T Cells,CD8/Treg Ratio,PD1 and CTLA-4 in Patients with Cervical Cancer

PURPOSE/OBJECTIVE(S)

To investigate the significance of chemoradiotherapy on regulatory T (Treg) cells, CD8 / Treg ratio, squamous cell carcinoma antigen (SCC), PD1, and CTLA-4 in the peripheral blood of cervical cancer (CC)patients.

MATERIALS/METHODS

A retrospective study was performed 56 cervical cancer patients treated with concurrent chemoradiotherapy from September 06, 2019 to April 19, 2021 were selected, in patients who underwent surgery. Flow cytometry was used to determine the levels of regulatory T cells, CD8 / Treg ratio, squamous cell carcinoma antigen, PD1, and CTLA-4 in the peripheral blood of patients before and after concurrent therapy, Differences in relative level values before and after treatment were calculated using statistical protocols such as the paired samples t-test.

RESULTS

The proportion of CD4+CD25+CD127low Treg in CD4+T cells was (15.96±4.29) % in cervical cancer patients and (9.76±4.21) % in healthy controls, and the difference between the two groups was statistically significant (P < 0.05). In different age groups, Treg, CD8 levels, CD4/CD8 ratio and CD8/Treg ratio before and after radiotherapy and chemotherapy had no significant relationship with age and pathological types (P > 0.05), but CD8/Treg ratio was higher in patients with adenocarcinoma than in patients with squamous cell carcinoma after radiotherapy and chemotherapy, and the difference was statistically significant (Z = -2.076 P = 0.038). For postoperative patients, CD8 levels were lower before and after chemoradiotherapy than after chemoradiotherapy (T = -2.320 P = 0.020). In terms of PD1, regardless of age, pathological type, the level of PD1 after radiotherapy and chemotherapy was higher than that before chemotherapy, and the difference was statistically significant. The level of adenocarcinoma (53.50±10.16) % was significantly higher than that of squamous carcinoma (43.72±11.89) % (T = -2.609 P = 0.011). The PD1 level of patients with cervical cancer radical resection (41.64±13.29) % was lower than that of patients without cervical cancer radical resection (46.84±10.61) %, the difference was statistically significant (T = 2.187 P = 0.031). The PD1 level of patients without pelvic lymph node metastasis (48.84±10.04) was significantly higher than that of patients with pelvic lymph node metastasis (42.96±10.85), and the difference was statistically significant (T = -2.019 P = 0.049), There were no significant differences in vascular positivity, invasion depth, stump positivity, pelvic lymph node positivity and Treg level, CD8 level, CTLA4 level, SCC, CD4/CD8 ratio, CD8/Treg ratio (ALL P > 0.05).

CONCLUSION

The level of Treg cells in patients with cervical cancer is significantly higher than that in healthy people, and it does not decrease immediately after radiotherapy and chemotherapy. Peripheral blood Treg, PD1, CD8 and CD8/Treg can reflect the immune function of the body, which may provide a certain reference for immunotherapy.

Long-Term Outcome of Rectal Cancer Patients Treated by High-Dose Radiotherapy and Concurrent Chemotherapy

PURPOSE/OBJECTIVE(S)

To explore the therapeutic efficacy and adverse effects of high-dose radiotherapy concurrently with chemotherapy in treating patients with non-metastatic rectal cancer.

MATERIALS/METHODS

Patients were enrolled if they were diagnosed with stage I-III rectal adenocarcinoma, refused surgery and received high-dose pelvic radiotherapy and concurrent chemotherapy instead. Their clinical data were retrospectively analyzed for calculating local control and survival rates. Treatment related toxicities was evaluated according to the Common Terminology Criteria for Adverse Events (version 5.0).

RESULTS

Between April 2006 and February 2021, a total of 93 patients in our medical center were eligible for this study, with a median age of 61 (range, 21-84) years. Of those, 86 (92.5%) patients had tumors located within 5 cm of the anal verge. There were 8 (8.6%), 30 (32.3%) and 55 (59.1%) patients diagnosed with stage I, II and III, respectively. All patients received fluorouracil-based chemotherapy (single-agent fluorouracil or FOLFOX regimen). The irradiation techniques included three-dimensional conformal and intensity-modulated radiation therapy. The median total radiation dose for gross tumor volume (GTV) was 80 (range, 60-90) Gy. The 15 (16.1%) patients refusing surgery before treatment received one course of radiation (60-70 Gy/30-35 Fr). And a 2-course radiation (Course 1, 45-50 Gy/25 Fr; Course 2: 24-40 Gy/12-20 Fr) were given to the 78 (83.9%) patients who failed to achieve clinical complete remission (cCR) after neoadjuvant chemoradiotherapy but still refused surgery, with a median interval of 79 (range, 35-195) days. The median follow-up duration was 66 (range, 10-161) months. The 3- and 5-year overall survival (OS) rates for all patients were 90.5% and 72.7%, respectively. The clinical complete remission rate at the end of chemoradiotherapy was 69.9%. Colostomy was performed in the 14 patients whose rectal tumor did not attain cCR or progressed. There was no grade 4/5 severe acute toxicity. No patient suffered from intestinal perforation. Only one patient developed anal stenosis. Because of rectal bleeding, blood transfusion was performed in 7 patients, and one patient underwent an enterostomy.

CONCLUSION

High-dose radiotherapy concurrent with chemotherapy brought encouraging survival outcomes, satisfactory organ preservation and acceptable short- and long-term side effects. It might be a safe and non-invasive alternative to abdominoperineal resection in rectal cancer patients refusing or unsuitable for surgery, especially for those with a low-position tumor.

Silva Classification System for HPV-Related EAC of Stage I ∼ IIIc1p Cervical Adenocarcinoma and Its Effect on Prognosis and Survival

PURPOSE/OBJECTIVE(S)

The proportion of adenocarcinoma in cervical cancer gradually increased and presented a younger trend. The previous pathological classification of cervical adenocarcinoma is difficult to provide reference for clinical treatment. In recent years, Silva classification, a new pathologic system for cervical adenocarcinoma, has been confirmed to be suitable for HPV-associated adenocarcinoma (HPVA), and has shown certain clinical application value in subsequent studies. Therefore, this study will retrospectively analyze the distribution of Silva typing system in patients with HPVA under standard treatment mode and its relationship with prognosis and survival.

MATERIALS/METHODS

From January 2010 to September 2021, 124 cervical adenocarcinoma patients with HPVA were retrospectively included, who underwent radical resection of cervical cancer. The HE staining sections of the patients were divided into SilvaA, SilvaB, and SilvaC types according to the Silva typing system. Kaplan-Meier calculation was used for single-factor analysis, and COX stepwise regression model was used for multi-factor analysis.

RESULTS

Of the 124 patients with HPVA who could be graded according to the Silva system, 16 (12.9%, 16/124) were SilvaA, 27 (21.7%, 27/124) SilvaB, and 81 (65.4%, 81/124) SilvaC. In Silva classification, FIGO staging of Silva A and B was stage I. And FIGO staging of Silva C was more significantly later than the staging of Silva A and B. All lymph node metastases and paruterine infiltrates were found only in Silva C. In addition, the patients with Silva C large mass accounted for a higher proportion (41.7%). SilvaA type cervical adenocarcinoma patients were in a survival state by the end of follow-up. Among Silva B, 3 patients died due to tumor, and the 5-year OS rate were 91.3%. Among SilvaC, 15 patients died due to tumor, and the 5-year OS rate were 76.5%. FIGO stage and lymph node invasion were the influencing factors for survival and prognosis of Silva classification (P <0.05). FIGO stage, tumor size, lymph node invasion, and paralegal invasion were the influencing factors for survival and prognosis of SilvaC patients (P <0.05).

CONCLUSION

Silva model classification system combined with clinicopathological features has certain clinical value for the prognostic guidance of HPVA patients. Among Silva classification, SilvaC had the worst prognosis. Late FIGO stage, lymph node metastasis, and paralegal infiltration are the influencing factors for survival and prognosis of SilvaC type.

[An improved 4-vessel intermittent occlusion method for establishing rat models of global cerebral ischemia-reperfusion injury]

OBJECTIVE

To improve the classical 4-vessel occlusion (4VO) model established by Pulsinelli and Brierley.

METHODS

Thirty-two male SD rats were randomized into sham operation group, I4VO-Con10 group, I4VO-Int10 group and I4VO-Int15 group. The sham surgery group underwent exposure of the bilateral vertebral arteries and carotid arteries without occlusion to block blood flow. The I4VO-Con10 group experienced continuous ischemia by occluding the bilateral vertebral arteries and carotid arteries for 10 minutes followed by reperfusion for 24 hours. The I4VO-Int10 and I4VO-Int15 groups were subjected to intermittent ischemia. The I4VO- Int10 group underwent 5 minutes of ischemia, followed by 5 minutes of reperfusion and another 5 minutes of ischemia, and then reperfusion for 24 hours. The I4VO-Int15 group experienced 5 minutes of ischemia followed by two cycles of 5 minutes of reperfusion and 5 minutes of ischemia, and then reperfusion for 24 hours. The regional cerebral blood flow (rCBF) was monitored with laser Doppler scanning, and survival of the rats was observed. HE staining was used to observe hippocampal pathologies to determine the optimal method for modeling. Another 48 rats were randomized into 6 groups, including a sham operation group and 5 model groups established using the optimal method. The 5 I4VO model groups were further divided based on the reperfusion time points (1, 3, 7, 14, and 28 days) into I4VO-D1, I4VO-D3, I4VO-D7, I4VO- D14, and I4VO- D28 groups. Body weight changes and survival of the rats were recorded. HE staining was used to observe morphological changes in the hippocampal, retinal and optic tract tissues. The Y-maze test and light/dark box test were used to evaluate cognitive and visual functions of the rats in I4VO-D28 group.

RESULTS

Occlusion for 5 min for 3 times at the interval of 5 min was the optimal method for 4VO modeling. In the latter 48 rats, the body weight was significantly lower than that of the sham-operated rats at 1, 3, 7, 14 and 28 days after modeling without significant difference in survival rate among the groups. The rats with intermittent vessel occlusion exhibited progressive deterioration of hippocampal neuronal injury and neuronal loss. Cognitive impairment was observed in the rats in I4VO-D28 group, but no obvious ischemic injury of the retina or the optic tract was detected.

CONCLUSION

The improved 4VO model can successfully mimic the main pathological processes of global cerebral ischemia-reperfusion injury without causing visual impairment in rats.

Identification of key DNA methylation changes on fasting plasma glucose: a genome-wide DNA methylation analysis in Chinese monozygotic twins

BACKGROUND

Elevated fasting plasma glucose (FPG) levels can increase morbidity and mortality even when it is below the diagnostic threshold of type 2 diabetes mellitus (T2DM). We conducted a genome-wide DNA methylation analysis to detect DNA methylation (DNAm) variants potentially related to FPG in Chinese monozygotic twins.

METHODS

Genome-wide DNA methylation profiling in whole blood of twins was performed using Reduced Representation Bisulfite Sequencing (RRBS), yielding 551,447 raw CpGs. Association between DNAm of single CpG and FPG was tested using a generalized estimation equation. Differentially methylated regions (DMRs) were identified using comb-P approach. ICE FALCON method was utilized to perform the causal inference. Candidate CpGs were quantified and validated using Sequenom MassARRAY platform in a community population. Weighted gene co-expression network analysis (WGCNA) was conducted using gene expression data from twins.

RESULTS

The mean age of 52 twin pairs was 52 years (SD: 7). The relationship between DNAm of 142 CpGs and FPG reached the genome-wide significance level. Thirty-two DMRs within 24 genes were identified, including TLCD1, MRPS31P5, CASZ1, and CXADRP3. The causal relationship of top CpGs mapped to TLCD1, MZF1, PTPRN2, SLC6A18, ASTN2, IQCA1, GRIN1, and PDE2A genes with FPG were further identified using ICE FALCON method. Pathways potentially related to FPG were also identified, such as phospholipid-hydroperoxide glutathione peroxidase activity and mitogen-activated protein kinase p38 binding. Three CpGs mapped to SLC6A18 gene were validated in a community population, with a hypermethylated direction in diabetic patients. The expression levels of 18 genes (including SLC6A18 and TLCD1) were positively correlated with FPG levels.

CONCLUSIONS

We detect many DNAm variants that may be associated with FPG in whole blood, particularly the loci within SLC6A18 gene. Our findings provide important reference for the epigenetic regulation of elevated FPG levels and diabetes.

Genetic and Environmental Correlation Analysis of Serum Creatinine Levels in Chinese Twins

Almost all creatinine is excreted by the kidney in individuals. Serum creatinine concentration, a widely used renal function index in clinical practice, can be affected by both genetic and environmental factors, as evidenced by current research exploring the relationship between these factors and kidney function. However, few studies have explored the heritability of serum creatinine in Asian populations. Therefore, we explored the genetic and environmental factors that affect the serum creatinine level in Asian populations. Participants in this study came from the Qingdao Twin Registry in China, and 374 pairs of twins were included, of which 139 pairs were dizygotic twins, whose ages ranged from 40 to 80 years old, and the serum creatinine level ranged from 10 to 126 μmol/L. Structural equation models were constructed using Mx software to calculate heritability, with adjusted covariates being age, sex, and body mass index. The results of heritability analysis showed that ACE was the best fit model. Serum creatinine level is influenced by genetic and environmental factors. The result of heritability was 35.44%, and the influence of shared environmental factors accounted for 52.13%. This study provided the relevant basis for future research on genetic and environmental factors affecting serum creatinine levels in Asian populations.

[Identification and verification of α-11 giardin-interacting protein]

OBJECTIVE

To identify and verify the interacting protein of α-11 giardin, so as provide the experimental evidence for studies on the α-11 giardin function.

METHODS

The yeast two-hybrid cDNA library of the Giardia lambia C2 strain and the bait plasmid of α-11 giardin were constructed. All proteins interacting with α-11 giardin were screened using the yeast two-hybrid system. α-11 giardin and all screened potential interacting protein genes were constructed into pBiFc-Vc-155 and pBiFc-Vn-173 plasmids, and co-transfected into the breast cancer cell line MDA-MB-231. The interactions between α-11 giardin and interacting proteins were verified using bimolecular fluorescence complementation (BiFC).

RESULTS

The yeast two-hybrid G. lambia cDNA library which was quantified at 2.715 × 10⁷ colony-forming units (CFU) and the bait plasmid containing α-11 giardin gene without an autoactivation activity were constructed. Following two-round positive screening with the yeast two-hybrid system, two potential proteins interacting with α-11 giardin were screened, including eukaryotic translation initiation factor 5A (EIF5A), calmodulin-dependent protein kinase (CAMKL) and nicotinamide adenine dinucleotide phosphate-specific glutamate dehydrogenase (NADP-GDH), hypothetical protein 1 (GL50803_95880), hypothetical protein 2 (GL50803_87261) and a protein from Giardia canis virus. The α-11 giardin and EIF5A genes were transfected into the pBiFc-Vc-155 and pBiFc-Vn-173 plasmids using BiFC, and the recombinant plasmids pBiFc-Vc-155-α-11 and pBiFc-Vn-173-EIF5A were co-tranfected into MDA-MB-231 cells, which displayed green fluorescence under a microscope, indicating the interaction between α-11 giardin and EIF5A protein in cells.

CONCLUSIONS

The yeast two-hybrid cDNA library of the G. lambia C2 strain has been successfully constructed, and six potential protein interacting with α-11 giardin have been identified, including EIF5A that interacts with α-11 giardin in cells.

Family history, waist circumference and risk of ischemic stroke: A prospective cohort study among Chinese adults

BACKGROUND AND AIMS

The associations between genetic factors and waist circumference (WC) with stroke risk have been evaluated in Western studies. However, evidence of this association has rarely been reported in the Chinese population. This study aimed to evaluate the association between WC and family history of stroke (FHS) with ischemic stroke (IS) risk among Chinese adults and to further explore the potential interaction of these associations.

METHODS AND RESULTS

The China Kadoorie Biobank (CKB) study recruited 35,508 participants aged 30-79 years from the Qingdao urban area during 2004-2008. A total of 33,355 participants were included in study. Cox regression analysis was used to estimate the multivariable-adjusted hazard ratios (HR) and 95% confidence intervals (CI) for the independent and interactional associations between FHS and WC and IS risk. Participants with FHS had a 29% (HR = 1.29, 95% CI: 1.12-1.50) higher IS risk than those without FHS. Participants with excessive WC (85 cm for males and 80 cm for females) had a 78% (HR = 1.78, 95% CI: 1.51-2.10) higher IS risk than those with normal WC. The combined effect of FHS and excessive WC on IS was statistically significant (HR = 2.29, 95% CI: 1.84-2.86). The present study further found statistically significant multiplicative interactions of FHS and WC with IS risk (Pinteraction < 0.001).

CONCLUSION

The present study indicated that FHS and WC were significantly associated with an increased risk of IS. The association between FHS and IS was associated with excessive WC.

Epigenome-wide association study in Chinese monozygotic twins identifies DNA methylation loci associated with blood pressure

BACKGROUND

Hypertension is a crucial risk factor for developing cardiovascular disease and reducing life expectancy. We aimed to detect DNA methylation (DNAm) variants potentially related to systolic blood pressure (SBP) and diastolic blood pressure (DBP) by conducting epigenome-wide association studies in 60 and 59 Chinese monozygotic twin pairs, respectively.

METHODS

Genome-wide DNA methylation profiling in whole blood of twins was performed using Reduced Representation Bisulfite Sequencing, yielding 551,447 raw CpGs. Association between DNAm of single CpG and blood pressure was tested by applying generalized estimation equation. Differentially methylated regions (DMRs) were identified by comb-P approach. Inference about Causation through Examination of Familial Confounding was utilized to perform the causal inference. Ontology enrichment analysis was performed using Genomic Regions Enrichment of Annotations Tool. Candidate CpGs were quantified using Sequenom MassARRAY platform in a community population. Weighted gene co-expression network analysis (WGCNA) was conducted using gene expression data.

RESULTS

The median age of twins was 52 years (95% range 40, 66). For SBP, 31 top CpGs (p < 1 × 10^-4) and 8 DMRs were identified, with several DMRs within NFATC1, CADM2, IRX1, COL5A1, and LRAT. For DBP, 43 top CpGs (p < 1 × 10^-4) and 12 DMRs were identified, with several DMRs within WNT3A, CNOT10, and DAB2IP. Important pathways, such as Notch signaling pathway, p53 pathway by glucose deprivation, and Wnt signaling pathway, were significantly enriched for SBP and DBP. Causal inference analysis suggested that DNAm at top CpGs within NDE1, MYH11, SRRM1P2, and SMPD4 influenced SBP, while SBP influenced DNAm at CpGs within TNK2. DNAm at top CpGs within WNT3A influenced DBP, while DBP influenced DNAm at CpGs within GNA14. Three CpGs mapped to WNT3A and one CpG mapped to COL5A1 were validated in a community population, with a hypermethylated and hypomethylated direction in hypertension cases, respectively. Gene expression analysis by WGCNA further identified some common genes and enrichment terms.

CONCLUSION

We detect many DNAm variants that may be associated with blood pressure in whole blood, particularly the loci within WNT3A and COL5A1. Our findings provide new clues to the epigenetic modification underlying hypertension pathogenesis.

The association of pulse pressure change with memory decline in middle-aged and older adults

BACKGROUND

Less is known regarding the association of pulse pressure (PP) with memory function. This study aimed to characterize long-term patterns of PP in middle-aged and older adults and explore their impact on subsequent change in memory function.

METHODS

Data from the English Longitudinal Study of Ageing (ELSA, 2004-2018), were analyzed. Totally, 3587 dementia-free participants with three measurements of BP were included. All three visits of PP (2004-2012) were used to characterize longitudinal patterns of PP by group-based trajectory modeling (GBTM). Generalized estimating equation (GEE) models were fitted to explore the impact of PP trajectories on change in memory over a subsequent 6-year period (2012-2018).

RESULTS

Using GBTM, three distinct trajectories of PP were identified: low-stable (38.1%), moderate-stable (48.6%), and elevated-increasing group (13.3%). GEE model suggested that memory declined over a 6-year period in all PP trajectories (all P_time  <0.001). The overall interactions between patterns of PP changes and time with memory were statistically significant (χ² _interaction  = 20.69, p = 0.002). Compared to participants in the low-stable group, those in the moderate-stable and elevated-increasing group exhibited a faster decline in memory.

CONCLUSIONS

Longitudinal patterns of moderate-stable and elevated-increasing PP were associated with an accelerated decrease in memory. Controlling BP instability may be a promising interventional strategy for preventing cognitive decline among older adults.

Association between pneumonia hospitalisation and long-term risk of cardiovascular disease in Chinese adults: A prospective cohort study

BACKGROUND

Lower respiratory tract infections, including pneumonia, have been associated with short-term increased risk of cardiovascular disease (CVD). However, there is only limited evidence about the long-term impact of pneumonia on the cardiovascular system beyond one year.

METHODS

We conducted a prospective matched cohort study based on data from the China Kadoorie Biobank study of 482,017 adults who were enrolled between June 25, 2004, and July 15, 2008, and were free of CVD at baseline and before pneumonia hospitalization. A total of 24,060 patients hospitalised with pneumonia were identified until December 31, 2018, and were matched on age, sex, urban or rural areas, and decile of the frailty index to 223,875 controls. We used the piecewise Cox proportional hazards model to estimate the hazard ratios (HRs) and their 95% confidence intervals (CIs) for pre-specified incident CVD outcomes, including ischaemic heart disease (IHD), arrhythmia, heart failure (HF), ischaemic stroke (IS), and hemorrhagic stroke (HS), at various time intervals through 10 years after pneumonia hospitalization.

FINDINGS

Of the 247,935 pneumonia cases and controls included, the mean age (standard deviation) was 53.5 (10.4), and 40.8% (101,159) were men. During follow-up, 2389 (9.9%) pneumonia cases developed IHD, 489 (2.0%) cases developed arrhythmia, 545 (2.3%) cases developed HF, 1764 (7.3%) cases developed IS, and 348 (1.4%) cases developed HS. After adjustment for sociodemographic characteristics, lifestyle factors, health status and medication, underlying conditions, and family history of CVD, the elevated CVD risk was highest within the first 30 days after pneumonia hospitalisation, with subsequent risk reductions varying by subtypes. The elevated risk remained until the eighth year after pneumonia hospitalisation for IHD, arrhythmia, and HF, with HRs (95% CIs) of 1.48 (1.13-1.93), 2.69 (1.70-4.25), and 4.36 (2.86-6.64), respectively. The risk of stroke associated with pneumonia hospitalisation remained elevated until the seventh year for IS (HR = 1.30; 95% CI: 1.04-1.63), and until the second year for HS (1.39; 1.07-1.80). The above associations were consistently observed across various characteristics of the participants.

INTERPRETATION

In middle-aged and older Chinese adults, pneumonia hospitalisation was associated with short- and long-term CVD risk, with the elevated risk of certain CVD outcomes persisting for up to 8 years.

FUNDING

National Natural Science Foundation of China, the National Key R&D Program of China, the Chinese Ministry of Science and Technology, the Kadoorie Charitable Foundation in Hong Kong, the UK Wellcome Trust.

A quasi-two-dimensional fluid experimental apparatus based on tank-in-tank configuration

The fluid tank is an essential facility for experimental research on fluid mechanics. However, owing to the hydrostatic fluid pressure, a fine uniformity of the narrow channel is difficult to be maintained in a tall narrow-channel tank. To address this issue, we proposed a quasi-two-dimensional fluid experimental apparatus based on a "tank-in-tank" configuration and built with an outer tank and an inner tank. The outer tank was cuboid-shaped and used to load the fluid medium, while the inner tank, consisting of two parallel glass plates, was embedded into the outer tank and served as the experimental channel. The hydrostatic pressure acting on the channel was balanced so that a high level of uniformity was maintained over the whole channel. The available height and width of the channel were 2800 and 1500 mm, respectively, while its gap distance could be adaptive from 0 to 120 mm. Experimental research on motion characteristics of circular disks falling in the quasi-2D channel was implemented to investigate the effects of the falling environment and disk geometry. Four distinct falling types were observed, and the wake flow fields of the falling disks were visualized. The Reynolds numbers of falling disks ranged from 400 to 63 000 presently. Chaotic motion and regular motion were demarcated at Re ≈ 30 000. An analytical model was established to predict the final average falling velocity and Reynolds number. Finally, potential directions for future research and improvements to the apparatus were suggested.

Genetic polymorphisms in MIR1208 and MIR5708 are associated with susceptibility to COPD in the Chinese population

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a complex disease characterized by limited airflow and is influenced by genetic and environmental factors. The purpose of this study was to investigate the effects of gene polymorphisms in MIR5708 and MIR1208 on COPD risk.

METHODS

Four single nucleotide polymorphisms (SNPs) in MIR5708 (rs6473227 and rs16907751) and MIR1208 (rs2608029 and rs13280095) were selected and genotyped among 315 COPD patients and 314 healthy controls using the Agena MassARRAY platform. SPSS 18.0 was used for statistical analysis and data processing. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the association between genetic variants of MIR1208 and MIR5708 and COPD risk.

RESULTS

The results suggested that rs16907751 variants in MIR5708 contributed to an increased susceptibility to COPD in the allelic (P = 0.001), co-dominant (homozygous) (P = 0.001), dominant (P = 0.017), recessive (P = 0.002), and additive (P = 0.002) models. The effects of MIR5708 and MIR1208 gene polymorphisms on the risk of COPD were age-, sex-, smoking status-, and BMI-related. Furthermore, the C-A and G-A haplotypes of rs2608029 and rs13280095 in MIR1208 were identified as risk factors for COPD in the population over 70 years (P = 0.029) and in women (P = 0.049), respectively. Finally, significant associations between rs16907751genotypes with pulse rate and forced expiratory volume in 1 s were found among COPD patients.

CONCLUSION

Genetic polymorphisms in MIR5708 and MIR1208 are associated with increased risk of COPD in China.

Multivariate genome-wide association study of depression, cognition, and memory phenotypes and validation analysis identify 12 cross-ethnic variants

To date, little is known about the pleiotropic genetic variants among depression, cognition, and memory. The current research aimed to identify the potential pleiotropic single nucleotide polymorphisms (SNPs), genes, and pathways of the three phenotypes by conducting a multivariate genome-wide association study and an additional pleiotropy analysis among Chinese individuals and further validate the top variants in the UK Biobank (UKB). In the discovery phase, the participants were 139 pairs of dizygotic twins from the Qingdao Twins Registry. The genome-wide efficient mixed-model analysis identified 164 SNPs reaching suggestive significance (P < 1 × 10-5). Among them, rs3967317 (P = 1.21 × 10-8) exceeded the genome-wide significance level (P < 5 × 10-8) and was also demonstrated to be associated with depression and memory in pleiotropy analysis, followed by rs9863698, rs3967316, and rs9261381 (P = 7.80 × 10-8-5.68 × 10-7), which were associated with all three phenotypes. After imputation, a total of 457 SNPs reached suggestive significance. The top SNP chr6:24597173 was located in the KIAA0319 gene, which had biased expression in brain tissues. Genes and pathways related to metabolism, immunity, and neuronal systems demonstrated nominal significance (P < 0.05) in gene-based and pathway enrichment analyses. In the validation phase, 12 of the abovementioned SNPs reached the nominal significance level (P < 0.05) in the UKB. Among them, three SNPs were located in the KIAA0319 gene, and four SNPs were identified as significant expression quantitative trait loci in brain tissues. These findings may provide evidence for pleiotropic variants among depression, cognition, and memory and clues for further exploring the shared genetic pathogenesis of depression with Alzheimer's disease.

Body mass index increases the recurrence risk of breast cancer: a dose-response meta-analysis from 21 prospective cohort studies

OBJECTIVE

The purpose of this study was to investigate the effect of body mass index (BMI) on the recurrence risk of breast cancer.

STUDY DESIGN

Dose-response meta-analysis.

METHODS

Cohort studies that included BMI and the recurrence of breast cancer were selected through various databases including PubMed, Web of Science, the China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals (VIP), and Wanfang Data Knowledge Service Platform (WanFang) until November 30, 2021. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of literature. A two-stage random-effects meta-analysis was performed to assess the dose-response relationship between BMI and breast cancer recurrence risk. Heterogeneity between studies is assessed using I².

RESULTS

The relative risk (RR) of BMI <25 kg/m² vs BMI ≥25 kg/m², BMI <30 kg/m² vs BMI ≥30 kg/m² were 1.09 (95% CI: 1.00-1.19) and 1.15 (95% CI: 1.04-1.27), suggesting that BMI had a significant effect on the recurrence risk of breast cancer, and there might be a dose-response relationship between them. A total of 21 studies were included in dose-response meta-analysis, which showed that there was a positive linear correlation between BMI and the risk of recurrence (RR = 1.02, 95% CI: 1.01-1.03). For every 1 kg/m² increment of BMI, the risk of recurrence increased by approximately 2%. In subgroup analyses, positive linear dose-response relationships between BMI and recurrence risk were observed among Asian and study period >10 years groups. For every 1 kg/m² increment of BMI, the risk of recurrence increased by 3.41% and 1.87%, respectively.

CONCLUSIONS

The recurrence risk of breast cancer increases with BMI, which is most obvious among Asian women.

[Management of the internal carotid artery during lateral skull base surgery: a series of 41 cases]

Objective: To introduce our experience on dealing with the internal carotid artery (ICA) during the resection of lateral skull base tumors, and to explore the reference values for using radiological findings to make a rational surgical plan. Methods: A retrospective study of patients who underwent resection of lateral skull base tumors involving ICA at Peking Union Medical College Hospital from May 2015 to May 2021 was conducted. The demographic information, preoperative examinations, diagnosis, surgical details and follow-ups were collected. A total of 41 patients were enrolled [24 (58.5%] females, 17 (41.5%) males], with an average age of 47.9 years. According to the preoperative imaging findings, the relationships between the tumors and ICA were divided into four types: adjacency, compression, invasion and ICA aneurysm. Results: The ICA was preserved in 32 (78.0%, 32/41) cases and was reconstructed in nine (22.0%, 9/41) cases. All the 27 (65.9%, 27/41) tumors adjacent to ICA were successfully separated from the artery. Among the 11 tumors compressing the ICA, six were resected with the involved ICA segment and vascular reconstruction was conducted. One (2.4%, 1/41) tumor invading ICA and two (4.9%, 2/41) ICA aneurysms required revascularization. The mean follow-up time was (26.1±2.9) months. There was no recurrence, except one case of adenoid cystic carcinoma which had brain metastases one year after surgery. Conclusions: According to the preoperative imaging, lateral skull base tumors adjacent to ICA can be detached from the vascular surface. Separation should be attempted first for tumors compressing ICA, and revascularization should be followed if separation failed. Vascular reconstruction is usually needed in the removal of tumors invading ICA and ICA aneurysms. Preoperative radiology can provide good references for planning a surgery for lateral skull base tumors.

Nonreproductive effects are more important than reproductive effects in a host feeding parasitoid

When female host feeding parasitoids encounter a potential host, they face a complicated trade-off between either laying an egg for investing in current reproduction or feeding on or killing the host for future reproduction. Few studies have measured these behavioral shift patterns in a given host-parasitoid association thus far. We systematically assessed the behavioral shifts and life history traits of a host feeding parasitoid, Necremnus tutae, on different instars of its host Tuta absoluta. N. tutae females, as idiobiont host feeding parasitoids, can act on the 1st–4th instar larvae of T. absoluta by either host feeding, parasitizing or host killing. Moreover, a significant behavioral shift was observed on different instar hosts. N. tutae preferred to feed on the young hosts (1st and 2nd instars), lay eggs on middle-aged hosts (3rd instars) and kill old hosts (4th instars) by ovipositor-mediated stinging. The offspring of N. tutae showed a significant female-biased sex ratio, with the number of instars of T. absoluta larvae that were parasitized increasing. Specifically, nonreproductive host mortality induced by host feeding and host killing accounted for high percentages of the total mortality (ranging from 70% on 3rd instar hosts to 88% on 1st instar and 4th instar hosts). We hypothesize that N. tutae could be not merely a parasitoid but also a predator. Our results shed light on the nonreproductive abilities of a host feeding parasitoid that should be given further attention, especially when evaluating the efficacy of parasitoids.

[Berberine inhibits erastin-induced ferroptosis of mouse hippocampal neuronal cells possibly by activating the Nrf2-HO-1/GPX4 pathway]

OBJECTIVE

To explore the mechanism by which berberine inhibits ferroptosis of mouse hippocampal neuronal cells (HT22).

METHODS

Cultured HT22 cells were pretreated with 30 or 60 μmol/L berberine for 2 h before exposure to 0.5 μmol/L erastin for 8 h, and the cell proliferation, intracellular ferric iron level, changes in intracellular reactive oxygen species (ROS) and cell apoptosis were detected using CCK-8, Fe²⁺ fluorescent probe, fluorescent dye (DAPI) and fluorescent probe (H2DCFH-DA). RT-qPCR and Western blotting were used to detect the mRNA and protein expressions of Nrf2, HO-1 and GPX4 in the cells. We further tested the effects of treatments with 2 μmol/L ML385 (a Nrf2 inhibitor), 60 μmol/L berberine and erastin in the cells to explore the protective mechanism of berberine against erastin-induced ferroptosis in the neuronal cells.

RESULTS

Treatment with 0.5 μmol/L erastin significantly lowered the viability of HT22 cells (P < 0.05) and increased the production of ROS, cell apoptosis rate and ferric iron level (P < 0.05). Pretreatment with 30 and 60 μmol/L berberine both significantly increased the vitality of erastin-exposed cells (P < 0.05) and lowered the levels of intracellular ROS and ferric iron content (P < 0.05). RT-qPCR and Western blotting showed that berberine obviously promoted the expressions of Nrf2, HO-1 and GPX4 in the cells (P < 0.05), and treatment with ML385 significantly inhibited the Nrf2-HO-1/GPX4 pathway, increased intracellular ROS and ferric iron contents and mitigated the protective effect of berberine against erastin-induced ferroptosis (P < 0.05).

CONCLUSION

Berberine can inhibit erastin-induced ferroptosis in HT22 cells possibly by activating the Nrf2-HO-1/ GPX4 pathway.

The Safety and Efficacy of Flow Diversion versus Conventional Endovascular Treatment for Intracranial Aneurysms: A Meta-analysis of Real-world Cohort Studies from the Past 10 Years

BACKGROUND

Although the flow diverter has advantages in the treatment of intracranial aneurysms, pooled studies that directly compare it with conventional endovascular treatments are rare.

PURPOSE

Our aim was to compare the safety and efficacy of flow-diverter and conventional endovascular treatments in intracranial aneurysms.

DATA SOURCES

We performed a comprehensive search of the literature using PubMed, EMBASE, and the Cochrane Database.

STUDY SELECTION

We included only studies that directly compared the angiographic and clinical outcomes of flow-diverter and conventional endovascular treatments.

DATA ANALYSIS

Random effects or fixed effects meta-analysis was used to pool the cumulative rate of short- and long-term angiographic and clinical outcomes.

DATA SYNTHESIS

Eighteen studies with 1001 patients with flow diverters and 1133 patients with conventional endovascular treatments were included; 1015 and 1201 aneurysm procedures were performed, respectively. The flow-diverter group had aneurysms of a larger size (standard mean difference, 0.22; 95% CI, 0.03-0.41; P = .026). There was a higher risk of complications in the flow-diverter group compared with the conventional endovascular group (OR, 1.4; 95% CI, 1.01-1.96; P = .045) during procedures. The follow-up angiographic results of flow-diverter treatment indicated a higher rate of complete occlusion (OR, 2.55; 95% CI, 1.70-3.83; P < .001) and lower rates of recurrence (OR, 0.24; 95% CI, 0.12-0.46; P < .001) and retreatment (OR, 0.31; 95% CI, 0.21-0.47; P < .001).

LIMITATIONS

Limitations include a retrospective, observational design in some studies, high heterogeneity, and selection bias.

CONCLUSIONS

Compared with the conventional endovascular treatments, the placement of a flow diverter may lead to more procedure-related complications, but there is no difference in safety, and it is more effective in the long term.

Analysis of genetic and environmental correlation between leisure activities and cognitive function in aging Chinese twins

OBJECTIVE

Leisure activity has been shown to be beneficial to mental health and cognitive aging. The biological basis of the correlation is, however, poorly understood. This study aimed at exploring the genetic and environmental impacts on correlation between leisure activities and cognitive function in the Chinese middle- and old-aged twins.

METHODS

Cognition measured using a screening test (Montreal Cognitive Assessment, MoCA) and leisure activities including intellectual and social activity were investigated on 379 complete twin pairs of middle- and old-aged twins. Univariate and bivariate twin models were fitted to estimate the genetic and environmental components in their variance and covariance.

RESULTS

Moderate heritability was estimated for leisure activities and cognition (0.44-0.53) but insignificant for social activity. Common environmental factors accounted for about 0.36 of the total variance to social activity with no significant contribution to leisure activity, intellectual activity and cognition. Unique environmental factors displayed moderate contributions (0.47-0.64) to leisure activities and cognition. Bivariate analysis showed highly and positively genetic correlations between leisure activities and cognition (r_G=0.80-0.96). Besides, intellectual activity and cognition presented low but significant unique environmental correlation (r_E=0.12).

CONCLUSIONS

Genetic factor had the moderate contribution to leisure activities and cognition. Cognitive function was highly genetically related to leisure activities. Intellectual activity and cognitive function may share some unique environmental basis.

Association between dairy consumption and ischemic heart disease among Chinese adults: a prospective study in Qingdao

BACKGROUND

Previous studies linking dairy consumption with ischemic heart disease (IHD) are almost from western countries, with little from China. The present study was to explore the relationship between dairy consumption and IHD among Chinese adults.

METHODS

The data for the present study was from the prospective cohort study of China Kadoorie Biobank in Qingdao, a total of 33,355 participants in the present study. An interviewer-administered laptop-based questionnaire was used to collect information on the consumption frequency of dairy, incident IHD cases were identified through Disease Surveillance Point System and the new national health insurance databases. Cox regression analyses were performed to estimate adjusted hazard ratios (HRs) and confidence interval for the relationship between the incidence of IHD and dairy consumption.

RESULTS

The baseline survey reported that 32.4% of males and 34.6% of females consumed dairy regularly (i.e. ≥ 4 days/week). Over an average of 9.2 years follow-up, 2712 new-onset IHD were documented. Compared with participants who never or rarely consume dairy, the HR of consumed dairy regularly was 0.85(0.73-0.98) for males (P < 0.05), while no significant benefits were identified for females.

CONCLUSIONS

Regular dairy consumption had an inverse association to the onset of IHD among males, with no similar findings for females.

[Etiology, diagnosis and treatment of infraoccluded primary second molars]

Infraocclusion is a phenomenon that the relative occlusal growth of a tooth stops after the period of active eruption and then the tooth becomes depressed below the occlusal plane. Infraocclusion occurred more commonly in children and the mostly affected teeth were the primary mandibular second molars. The occlusal problem caused by infraocclusion may progressively worsen with age. This review summarizes the etiology, diagnosis and treatment of infraoccluded second primary molars, so as to provide reference for the dental clinicians.

Genome-wide DNA methylation analysis of pulmonary function in middle and old-aged Chinese monozygotic twins

BACKGROUND

Previous studies have determined the epigenetic association between DNA methylation and pulmonary function among various ethnics, whereas this association is largely unknown in Chinese adults. Thus, we aimed to explore epigenetic relationships between genome-wide DNA methylation levels and pulmonary function among middle-aged Chinese monozygotic twins.

METHODS

The monozygotic twin sample was drawn from the Qingdao Twin Registry. Pulmonary function was measured by three parameters including forced expiratory volume the first second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio. Linear mixed effect model was used to regress the methylation level of CpG sites on pulmonary function. After that, we applied Genomic Regions Enrichment of Annotations Tool (GREAT) to predict the genomic regions enrichment, and used comb-p python library to detect differentially methylated regions (DMRs). Gene expression analysis was conducted to validate the results of differentially methylated analyses.

RESULTS

We identified 112 CpG sites with the level of P < 1 × 10^-4 which were annotated to 40 genes. We identified 12 common enriched pathways of three pulmonary function parameters. We detected 39 DMRs located at 23 genes, of which PRDM1 was related to decreased pulmonary function, and MPL, LTB4R2, and EPHB3 were related to increased pulmonary function. The gene expression analyses validated DIP2C, ASB2, SLC6A5, and GAS6 related to decreased pulmonary function.

CONCLUSION

Our DNA methylation sequencing analysis on identical twins provides new references for the epigenetic regulation on pulmonary function. Several CpG sites, genes, biological pathways and DMRs are considered as possible crucial to pulmonary function.

Heritability and genome-wide association study of blood pressure in Chinese adult twins

BACKGROUND

Blood pressure (BP) is an independent and important factor for chronic diseases such as cardiovascular diseases and diabetes.

METHODS

We firstly conducted twin modeling analyses to explore the heritability of BP, including systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP) and mean arterial pressure (MAP), and then performed genome-wide association studies to explore the associated genomic loci, genes, and pathways.

RESULTS

A total of 380 Chinese twin pairs were included. The AE model containing additive genetic parameter (A) and unique/non-shared environmental parameter (E) was the best fit model, with A accounting for 53.7%, 50.1%, 48.1%, and 53.3% for SBP, DBP, PP and MAP, respectively. No SNP was found to reach the genome-wide significance level (p < 5 × 10^-8 ), however, three, four, 14 and nine SNPs were found to exceed suggestive significance level (p < 1 × 10^-5 ) for SBP, DBP, PP, and MAP, respectively. And after imputation, 46, 37, 91 and 61 SNPs were found to exceed the suggestive significance level for SBP, DBP, PP, and MAP, respectively. In gene-based analysis, 53 common genes were found among SBP, DBP, PP, and MAP. In pathway enrichment analysis, 672, 706, 701, and 596 biological pathways were associated with SBP, DBP, PP, and MAP, respectively (p < 0.05).

CONCLUSION

Our study suggests that BP is moderately heritable in the Chinese population and could be mediated by a series of genomic loci, genes, and pathways. Future larger-scale studies are needed to confirm our findings.