[Early experience with mechanical hemodynamic support for catheter ablation of malignant ventricular tachycardia]

Objective: To explore the role of mechanical hemodynamic support (MHS) in mapping and catheter ablation of patients with hemodynamically unstable ventricular tachycardia (VT), report single-center experience in a cohort of consecutive patients receiving VT ablation during MHS therapy, and provide evidence-based medical evidence for clinical practice. Methods: This was a retrospective cohort study. Patients with hemodynamically unstable VT who underwent catheter ablation with MHS at Beijing Anzhen Hospital, Capital Medical University between August 2021 and December 2023 were included. Patients were divided into rescue group and preventive group according to the purpose of treatment. Their demographic data, periprocedural details, and clinical outcomes were collected and analyzed. Results: A total of 15 patients with hemodynamically unstable VT were included (8 patients in the rescue group and 7 patients in the preventive group). The acute procedure was successful in all patients. One patient in the rescue group had surgical left ventricular assist device (LVAD) implantation, remaining 14 patients received extracorporeal membrane oxygenation (ECMO) for circulation support. ECMO decannulation was performed in 12 patients due to clinical and hemodynamic stability, of which 6 patients were decannulation immediately after surgery and the remaining patients were decannulation at 2.0 (2.5) d after surgery. Two patients in the rescue group died during the index admission due to refractory heart failure and cerebral hemorrhage. During a median follow-up of 30 d (1 d to 12 months), one patient with LVAD had one episode of ventricular fibrillation at 6 months after discharge, and no further episodes of ventricular fibrillation and/or VT occurred after treatment with antiarrhythmic drugs. No malignant ventricular arrhythmia occurred in the remaining 12 patients who were followed up. Conclusions: MHS contributes to the successful completion of mapping and catheter ablation in patients with hemodynamically unstable VT, providing desirable hemodynamic status for emergency and elective conditions.

[Analysis of dyslipidemia management status in atrial fibrillation patients with very high and high risk of atherosclerotic cardiovascular disease]

Objective: To analyze the status of statins use and low-density lipoprotein cholesterol (LDL-C) management in patients with atrial fibrillation (AF) and very high/high risk of atherosclerotic cardiovascular disease (ASCVD) from Chinese Atrial Fibrillation Registry (CAFR). Methods: A total of 9 119 patients with AF were recruited in CAFR between January 1, 2015 to December 31, 2018, patients at very high and high risk of ASCVD were included in this study. Demographics, medical history, cardiovascular risk factors, and laboratory test results were collected. In patients with very high-risk, a threshold of 1.8 mmol/L was used as LDL-C management target and in patients with high risk, a threshold of 2.6 mmol/L was used as LDL-C management target. Statins use and LDL-C compliance rate were analyzed, multiple regression analysis was performed to explore the influencing factors of statins use. Results: 3 833 patients were selected (1 912 (21.0%) in very high risk of ASCVD group and 1 921 (21.1%) in high risk of ASCVD group). The proportion of patients with very high and high risk of ASCVD taking statins was 60.2% (1 151/1 912) and 38.6% (741/1 921), respectively. Attainment rate of LDL-C management target in patients with very high and high risk were 26.7% (511/1 912) and 36.4% (700/1 921), respectively. Conclusion: The proportion of statins use and attainment rate of LDL-C management target are low in AF patients with very high and high risk of ASCVD in this cohort. The comprehensive management in AF patients should be further strengthened, especially the primary prevention of cardiovascular disease in AF patients with very high and high risk of ASCVD.

[The timing of pericardial drainage catheter removal and restart of the anticoagulation in patients suffered from perioperative pericardial tamponade during atrial fibrillation catheter ablation and uninterrupted dabigatran: Experiences from 20 cases]

Objective: To investigate the timing of pericardial drainage catheter removal and restart of the anticoagulation in patients with atrial fibrillation (AF) suffered from perioperative pericardial tamponade during atrial fibrillation catheter ablation and uninterrupted dabigatran. Methods: A total of 20 patients with pericardial tamponade, who underwent AF catheter ablation with uninterrupted dabigatran in Beijing Anzhen Hospital from January 2019 to August 2021, were included in this retrospective analysis. The clinical characteristics of enrolled patients, information of catheter ablation procedures, pericardial tamponade management, perioperative complications, the timing of pericardial drainage catheter removal and restart of anticoagulation were analyzed. Results: All patients underwent pericardiocentesis and pericardial effusion drainage was successful in all patients. The average drainage volume was (427.8±527.4) ml. Seven cases were treated with idarucizumab, of which 1 patient received surgical repair. The average timing of pericardial drainage catheter removal and restart of anticoagulation in 19 patients without surgical repair was (1.4±0.7) and (0.8±0.4) days, respectively. No new bleeding, embolism and death were reported during hospitalization and within 30 days following hospital discharge. Time of removal of pericardial drainage catheter, restart of anticoagulation and hospital stay were similar between patients treated with idarucizumab or not. Conclusion: It is safe and reasonable to remove pericardial drainage catheter and restart anticoagulation as soon as possible during catheter ablation of atrial fibrillation with uninterrupted dabigatran independent of the idarucizumab use or not in case of confirmed hemostasis.

Radiation Therapy Decision Making Process and Operations for COVID-19 Positive Patients

Purpose/Objective(s)

A challenging clinical dilemma during the COVID-19 pandemic is management of cancer patients who test positive for COVID. Given the need to balance the risk of disease progression with the risk of transmission to other patients and staff, radiation therapy for these patients requires careful consideration and modification of standard workflows. It is also critical to develop processes to mitigate radiation treatment interruption, which can affect patient outcomes. The objective of this study was to report the clinical operations and outcomes for COVID positive patients receiving radiation therapy during the pandemic at a tertiary cancer center including 2 network locations.

Materials/Methods

During March 2020 to March 2022, the Radiation Oncology COVID committee (RO COVID) developed an integrated process to triage patients, provide treatment recommendations, and implement infection control procedures to safely deliver radiation therapy to COVID positive patients. Policies were created for each center with multidisciplinary input from infectious disease, radiation oncology, radiation therapy, and nursing. All COVID positive patients were presented to the RO COVID group and evaluated for clinical urgency, benefit with radiation, and life expectancy. If deemed necessary, a limited planned break or hypofractionated regimen was recommended to minimize staff exposure. We conducted a retrospective review of COVID positive patients with different primary malignancies treated through the COVID positive pathway.

Results

A total of 68 COVID positive patients were treated with the COVID positive pathway (HN 15, Breast 9, CNS 8, GU 8, GYN, 7, Thoracic 6, GI 5, HEME 5, PED 3, SARC 2). The median age was 57.1 years (IQR 45.8-63.4) and 47% were female. There were 39 patients (57%) who were asymptomatic and were tested for routine pre-radiation screening or due to concerns of COVID exposure. Twenty-three (34%) patients were treated with palliative intent and 8 (12%) were treated for an emergent indication (i.e., spinal cord compression, bleeding). Thirteen (19%) patients were receiving radiation treatment, had a treatment break (7-21 days), and then resumed their radiation course. All treatments were successfully completed without known nosocomial spread of COVID to staff or other patients. Among this heterogenous group of patients, 58 (85%) were alive with a median follow up of 2 months (IQR 0.5-7.5). COVID infection may have contributed to 3 out of 10 deaths (4% of total cohort). The remaining deaths were due to progression of disease or other non-COVID causes.

Conclusion

In this study, COVID positive patients were safely treated with radiation therapy through a comprehensive decision making and clinical operations pathway taking into account evolving COVID guidelines for three different variant surges. Although limited in follow up, patient outcomes are promising with few COVID-related deaths and low overall mortality rates, even with hypofractionated regimens.

[A comparison of CAS risk model and CHA2DS2-VASc risk model in guiding anticoagulation treatment in Chinese patients with non-valvular atrial fibrillation]

Objective: To compare the differences between CAS risk model and CHA₂DS₂-VASc risk score in predicting all cause death, thromboembolic events, major bleeding events and composite endpoint in patients with nonvalvular atrial fibrillation. Methods: This is a retrospective cohort study. From the China Atrial Fibrillation Registry cohort study, the patients with atrial fibrillation who were>18 years old were randomly divided into CAS risk score group and CHA₂DS₂-VASc risk score group respectively. According to the anticoagulant status at baseline and follow-up, patients in the 2 groups who complied with the scoring specifications for anticoagulation were selected for inclusion in this study. Baseline information such as age and gender in the two groups were collected and compared. Follow-up was performed periodically to collect information on anticoagulant therapy and endpoints. The endpoints were all-cause death, thromboembolism events and major bleeding, the composite endpoint events were all-cause death and thromboembolism events. The incidence of endpoints in CAS group and CHA₂DS₂-VASc group was analyzed, and multivariate Cox proportional risk model was used to analyze whether the incidence of the endpoints was statistically different between the two groups. Results: A total of 5 206 patients with AF were enrolled, average aged (63.6±12.2) years, and 2092 (40.2%) women. There were 2 447 cases (47.0%) in CAS risk score group and 2 759 cases (53.0%) in CHA₂DS₂-VASc risk score group. In the clinical baseline data of the two groups, the proportion of left ventricular ejection fraction<55%, non-paroxysmal atrial fibrillation, oral warfarin and HAS BLED score in the CAS group were lower than those in the CHA₂DS₂-VASc group, while the proportion of previous diabetes history and history of antiplatelet drugs in the CAS group was higher than that in the CHA₂DS₂-VASc group, and there was no statistical difference in other baseline data. Patients were followed up for (82.8±40.8) months. In CAS risk score group, 225(9.2%) had all-cause death, 186 (7.6%) had thromboembolic events, 81(3.3%) had major bleeding, and 368 (15.0%) had composite endpoint. In CHA₂DS₂-VASc risk score group, 261(9.5%) had all-cause death 209(7.6%) had thromboembolic events, 112(4.1%) had major bleeding, and 424 (15.4%) had composite endpoint. There were no significant differences in the occurrence of all-cause death, thromboembolic events, major bleeding and composite endpoint between anticoagulation in CAS risk score group and anticoagulation in CHA₂DS₂-VASc risk score group (log-rank P =0.643, 0.904, 0.126, 0.599, respectively). Compared with CAS risk score, multivariable Cox proportional hazards regression models showed no significant differences for all-cause death, thromboembolic events, major bleeding and composite endpoint between the two groups with HR(95%CI) 0.95(0.80-1.14), 1.00(0.82-1.22), 0.83(0.62-1.10), 0.96(0.84-1.11), respectively. All P>0.05. Conclusions: There were no significant differences between CAS risk model and CHA₂DS₂-VASc risk score in predicting all-cause death, thromboembolic events, and major bleeding events in Chinese patients with non-valvular atrial fibrillation.

[Efficacy and safety of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation and hypertrophic cardiomyopathy]

Objective: To evaluate the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOAC) in patients with atrial fibrillation (AF) and hypertrophic cardiomyopathy (HCM). Methods: This study was a prospective cohort study. The data of this study were based on the Chinese Atrial Fibrillation Registry (CAFR) Study, which was a prospective, multicenter registry study. The CAFR Study enrolled inpatients and outpatients with AF from 31 hospitals. Patients with AF and HCM were selected from August 2011 to December 2018. The patients were divided into NOAC-treated group and warfarin-treated group. General clinical data, echocardiographic results and treatment options were collected and compared between the two groups. Patients were followed up every 6 months; outcome events included effective endpoint events(thromboembolism)and safety endpoint events(major bleeding). The incidence of endpoint events in both groups was calculated and compared. Cox proportional hazards regression models and Kaplan-Meier survival analysis were performed to determine the association between NOAC use and endpoint events. Results: A total of 393 patients were included (average age: (60.5±11.8) years, 252 men (64.1%)). There were 133 (34.0%) patients in the NOAC-treated group and 260 (66.0%) patients in the warfarin-treated group. Compared with the warfarin-treated group, the patients in the NOAC-treated group had a higher proportion of paroxysmal AF, catheter ablation of AF, a lower proportion of hypertension, ischemic stroke/transient ischemic attack (TIA), lower heart rate, lower usage rate of angiotensin-converting enzyme inhibitors(ACEI)/angiotensin receptor blockers(ARB), β-blockers, non-dihydropyridine calcium channel blockers(NDH-CCB)(P<0.05). There were no significant differences on the echocardiographic results, including interventricular septal thickness, left ventricular posterior wall thickness, left ventricular end-diastolic diameter, left atrial diameter, left ventricular ejection fraction(P>0.05). After a follow-up of 42 (24, 60)months, the incidence rates of thromboembolism were 1.63 and 2.10 events per 100 person-years for NOAC-and warfarin-treated group, and those of major bleeding were 0.66 and 1.03 events per 100 person-years. Kaplan-Meier survival analysis showed survival rates free from endpoint events were similar between NOAC-treated group and warfarin-treated group(thromboembolism-free survival comparison, P=0.476; major bleeding-free survival comparison, P=0.855). Cox multivariate regression analysis revealed that there was no significant difference on risk of thromboembolism(HR=1.21, 95%CI: 0.42-3.50, P=0.720) and major bleeding(HR=1.50, 95%CI: 0.27-8.41, P=0.642) between NOAC-treated and warfarin-treated group. Conclusion: Patients with AF and HCM can be safely and effectively treated with NOAC.

[Effectiveness and safety of idarucizumab in the management of perioperative complications of atrial fibrillation catheter ablation in atrial fibrillation patients under dabigatran therapy]

Objective: To investigate the efficacy and safety of idarucizumab in the treatment of perioperative cardiac tamponade and thromboembolic events during catheter ablation in atrial fibrillation (AF) patients under dabigatran therapy. Methods: This study was a retrospective analysis enrolling patients under dabigatran therapy, who underwent catheter ablation for AF at Beijing Anzhen Hospital from January 2019 to December 2020 and developed perioperative cardiac tamponade or acute ischemic stroke (AIS) and received idarucizumab to reverse the anticoagulant effect of dabigatran. Patients' age, sex, renal function, coagulation test and safety events at 30 d after idarucizumab administration were collected and analyzed. The clinical presentation and prognosis were also analyzed. Results: A total of 7 patients were included, 2 (2/7) were male, mean age was (66.3±11.2) years, serum creatinine level was (66.3±13.6) μmol/L, estimated glomerular filtration rate was (89.4±11.2) ml·min-1·1.73 m-2, CHA2DS2-VASc and HAS-BLED scores were (3.2±1.9) and (1.3±1.3), respectively. Five patients (5/7) developed cardiac tamponade during the perioperative period and the time interval to the last dose of dabigatran was (6.3±2.6) h. Idarucizumab was given at (36.4±16.7) min after the definitive diagnosis of cardiac tamponade. A significant decrease of activated partial thromboplastin time was achieved after idarucizumab administration in all five cases. Pericardial puncture and drainage were applied to all patients (5/5) with cardiac tamponade, the drainage volume was (1 037.0±846.9) ml, the retention time of pericardial drainage catheter was (27.9±13.9) h, and the recovery time of anticoagulation was (28.4±13.2) h. One patient (1/5) underwent thoracotomy for hemostasis due to excessive blood loss with the aim of ensuring complete hemostasis. Bleeding occurred in 1 patient (1/5) after the first restart of anticoagulation. AIS occurred in 2 patients (2/7) after operation. One case (1/2) received intravenous thrombolysis after receiving 5.0 g idarucizumab, no hemorrhagic transformation was observed, and the recovery process was satisfactory. Another patient in this group experienced significantly prolonged onset time and 5.0 g idarucizumab was applied before intravascular thrombectomy, there was no bleeding complication in this patient after thrombectomy. At the time of discharge, the consciousness was not significantly improved, and the muscle strength of the right lower limb was recovered somehow compared with that before operation. No hypersensitivity reactions or thrombotic events occurred in these patients within 30 days of the administration of idarucizumab. Conclusion: In AF catheter ablation-associated cardiac tamponade and AIS, idarucizumab is safe and effective in rapidly reversing the anticoagulant effect of dabigatran, use of thrombectomy saves valuable time for timely hemostasis and improvement of cerebral blood circulation.

Circ_CHFR expedites cell growth, migration and inflammation in ox-LDL-treated human vascular smooth muscle cells via the miR-214-3p/Wnt3/β-catenin pathway

OBJECTIVE

Atherosclerosis (AS) is a representative inflammatory vascular disease. This study explored the molecular pathogenesis of AS based on circular RNA (circRNA), the checkpoint with forkhead-associated and ring-finger domains (circ_CHFR).

PATIENTS AND METHODS

The cell model of AS in vitro was established by stimulating human vascular smooth muscle cells (VSMCs) with oxidized low-density lipoprotein (ox-LDL). The RNA expression was measured by quantitative Real-time polymerase chain reaction (qRT-PCR). Cell viability and colony formation ability were separately evaluated using 3-(4, 5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) and colony formation assay. Cell migration was assessed via the transwell assay. The inflammation injury was analyzed by enzyme-linked immunosorbent assay (ELISA). Associated proteins were determined through Western blot. The combination of hypothetic targets was ascertained using Dual-Luciferase reporter assay.

RESULTS

Circ_CHFR was up-regulated in AS serums and ox-LDL-stimulated VSMCs. Circ_CHFR depletion weakened the ox-LDL-induced promotion of cell growth, migration and inflammation in VSMCs. Circ_CHFR positively regulated Wnt3 expression and the downregulation of Wnt3 abrogated the ox-LDL-triggered injuries in VSMCs. Circ_CHFR functioned as the sponge of microRNA-214-3p (miR-214-3p) and miR-214-3p targeted Wnt3. Circ_CHFR regulated cell growth, migration and inflammation via regulating the expression of Wnt3 as a competitive endogenous RNA (ceRNA) of miR-214 in ox-LDL-treated VSMCs. Circ_CHFR/miR-214-3p axis mediated the Wnt3/β-catenin signal pathway.

CONCLUSIONS

Circ_CHFR contributed to the progression of AS through the miR-214-3p/Wnt3/β-catenin signals, which illuminated the molecular mechanism of AS and suggested circ_CHFR might be an index for AS treatment.

Serum soluble ST2 is a potential long-term prognostic biomarker for transient ischaemic attack and ischaemic stroke

BACKGROUND AND PURPOSE

Soluble ST2 (sST2) is a promising biomarker in inflammation, atherosclerosis and cardiovascular diseases. We investigated the association between serum sST2 and poor outcome in patients with transient ischaemic attack (TIA)/ischaemic stroke.

METHODS

Patients within 24 h after onset and with measured serum sST2 were prospectively enrolled in this study. Poor outcome was a combination of a new stroke event (ischaemic or haemorrhagic) and all-cause death within 90 days and 1 year. The associations of serum sST2 with poor outcome were analysed by Cox proportional hazards.

RESULTS

Among the 430 patients included, the median (interquartile range) sST2 was 17.72 (9.31-28.84) ng/mL. A total of 19 (4.4%) and 38 (8.8%) patients experienced poor outcome within 90 days and 1 year, respectively. Compared with the lowest sST2 tertile, hazard ratios (HRs) [95% confidence intervals (CI)] for the highest tertile were 5.14 (1.43-18.51) for poor outcome within 90 days and 3.00 (1.29-6.97) at 1 year after multivariate adjustments. Adding sST2 to a prediction model significantly improved risk stratification of poor outcome in TIA/ischaemic stroke, as observed by the continuous net reclassification improvement of 60.98% (95% CI, 15.37-106.6%, P = 0.009) and integrated discrimination improvement of 2.63% (95% CI, 0.08-5.18%, P = 0.043) at 90 days and the continuous net reclassification improvement of 41.68% (95% CI, 8.74-74.61%, P = 0.013) at 1 year.

CONCLUSIONS

Increased serum sST2 levels in TIA/ischaemic stroke were associated with increased risks of poor outcome within 90 days and 1 year, suggesting that serum sST2 may be a potential long-term prognostic biomarker for TIA/ischaemic stroke.

[Clinical characteristics of left atrial appendage thrombus in patients with hypertrophic cardiomyopathy and non-valvular atrial fibrillation]

Objective: To investigate the incidence and clinical characteristics of left atrial appendage (LAA) thrombus in patients with hypertrophic cardiomyopathy (HCM) and non-valvular atrial fibrillation (AF) . Methods: Data from 10 440 patients with AF who had undergone transesophageal echocardiography (TEE) before cardioversion or catheter ablation at Beijing Anzhen Hospital from April 2006 to December 2018 were retrospectively screened. Two hundred and five HCM patients were included, 820 AF patients with the same CHA(2)DS(2)-VASc score over the same period were selected as the control group. HCM patients were divided into two subgroups based on presence or absence of LAA thrombus/sludge. The baseline of clinical information, transthoracic echocardiographic and TEE measures were compared among all the groups. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of left atrial diameter (LAD) for LAA thrombus/sludge. Multivariate logistic regression analysis was applied to analyze the correlative factors of LAA thrombus/sludge in HCM patients. Results: The incidences of LAA thrombus or sludge were higher in HCM group than in control group (10.7% (22/205) vs. 0.7% (6/820); 8.8% (18/205) vs.7.0% (57/820), P<0.001) . In HCM patients, LAD was significantly larger in LAA thrombus/sludge subjects than in those without thrombus/sludge ((48.9±5.1)mm vs. (45.2±6.1) mm, P<0.001). CHA(2)DS(2)-VASc score was similar between the two subgroups ((2.0±1.4) vs. (1.8±1.4), P>0.05). There was no difference in the rate of patients with a CHA(2)DS(2)-VASc scores ≥2 between the subgroups(62.5% (25/40) vs. 57.0% (94/165), P=0.525). The incidences of LAA thrombus in HCM and AF patients with CHA(2)DS(2)-VASc scores of 0, 1 and 2 were 8.8% (3/34) , 9.6% (5/52) , 11.8% (11/119) , respectively; and the rate of LAA sludge were 8.8% (3/52) , 7.7% (4/52) , 9.2% (11/119) , respectively. The cut off value of LAD for the diagnosis of LAA thrombus/sludge was 44.5 mm. Multivariate logistic regression analysis showed that LAD≥44.5 mm (OR=5.134, 95%CI 1.862-14.156, P=0.002) , non-paroxysmal AF (OR=2.782, 95%CI 1.238-6.252, P=0.013) , previous thromboembolism or stroke (OR=1.820, 95%CI 0.774-4.227, P=0.017) were independent determinants of LAA thrombus/sludge. Conclusions: The incidence of LAA thrombus/sludge is higher in patients with HCM and AF than in AF patients without HCM. The CHA(2)DS(2)-VASc score is similar between HCM and AF patients with LAA thrombus/sludge and those without thrombus/sludge. Patients with CHA(2)DS(2)-VASc score 0-1 are also likely to suffer LAA thrombus/sludge. Left atrial enlargement is associated with LAA thrombus/sludge.

Roles of UGT2B7 C802T gene polymorphism on the efficacy of morphine treatment on cancer pain among the Chinese han population

Background

Morphine is a common analgesic often used to manage chronic pain, especially for patients with pain due to malignancies. Since UGT2B7 plays an important role in the metabolism of morphine, UGT2B7 gene mutation may influence the efficacy of morphine in patients with cancer being treated by this medication.

Aims

The aim of this study is to investigate the relationship between the polymorphisms of UGT2B7 and the efficacy of morphine treatment on cancer pain among the Chinese Han population.

Materials and Methods

A total of 120 patients with cancer pain were enrolled in this study. Morphine was administrated through patient-controlled analgesia infusion pump, and the visual analog score (VAS) was used for pain assessment at 0.5, 4, 6, 12, 24, 48, and 72-h post morphine treatment, respectively. The plasma concentration of morphine and genetic polymorphism of UGT2B7 C802T and G221T was analyzed, respectively.

Results

The frequencies of UGT2B7 C802T were CC: 13.33%, CT: 45% and TT: 41.67%, and the frequencies of UGT2B7 G221T were GG: 76.67%, GT: 22.5% and TT: 0.83%. Moreover, the VAS score of patients with either C802T CT or TT was significantly higher than that in patients with C802T CC. However, no difference of VAS scores was observed between patients carrying G221T GG and patients carrying G221T GT. The plasma concentration of morphine for patients with the C802T CC was significantly lower than that in patients carrying C802T CT or TT, while there was no significant difference in the level of morphine between patients with G221T GG and G221T GT.

Conclusion

The polymorphism of UGT2B7 C802T, but not UGT2B7 G221T, has been associated with the efficacy of morphine treatment on cancer pain among Chinese Han population.

A C-type lectin with a single carbohydrate-recognition domain involved in the innate immune response of Tribolium castaneum

C-type lectins are one of the pattern-recognition proteins involved in innate immunity in invertebrates. Although there are 16 C-type lectin genes that have been identified in the genome of Tribolium castaneum, their functions and mechanisms in innate immunity remain unknown. Here, we identified one C-type lectin orthologue, TcCTL6 (TC003708), by sequencing random clones from the cDNA library of the coleopteran beetle, T. castaneum. TcCTL6 contains a 654 bp open reading frame encoding a protein of 217 amino acids that includes a single carbohydrate-recognition domain. The expression of TcCTL6 was significantly induced by Escherichia coli, Staphylococcus aureus and stimulation with carbohydrates, including lipopolysaccharide and peptidoglycan. A binding assay suggested that the recombinant TcCTL6 not only bound to lipopolysaccharide and peptidoglycan but also bound to Gram-positive (S. aureus, Bacillus subtilis and Bacillus thuringiensis) and Gram-negative bacteria (E. coli and Pseudomonas aeruginosa) in the presence of calcium ions. Furthermore, when TcCTL6 was knocked down by RNA interference, four antimicrobial peptides (attacin1, attacin2, coleoptericin1 and coleoptericin2) were significantly decreased. These results demonstrate that TcCTL6 plays a vital role in the immune response towards pathogen infection by influencing the expression of antimicrobial peptides and the agglutination of bacteria in the presence of calcium ions in T. castaneum.