Purification, identification and Cryo-EM structure of prostatic acid phosphatase in human semen.

Prostatic acid phosphatase (PAP) is a glycoprotein that plays a crucial role in the hydrolysis of phosphate ester present in prostatic exudates. It is a well-established indicator for prostate cancer due to its elevated serum levels in disease progression. Despite its abundance in semen, PAP's influence on male fertility has not been extensively studied. In our study, we report a significantly optimized method for purifying human endogenous PAP, achieving remarkably high efficiency and active protein recovery rate. This achievement allowed us to better analyze and understand the PAP protein. We determined the cryo-electron microscopic (Cryo-EM) structure of prostatic acid phosphatase in its physiological state for the first time. Our structural and gel filtration analysis confirmed the formation of a tight homodimer structure of human PAP. This functional homodimer displayed an elongated conformation in the cryo-EM structure compared to the previously reported crystal structure. Additionally, there was a notable 5-degree rotation in the angle between the α domain and α/ß domain of each monomer. Through structural analysis, we revealed three potential glycosylation sites: Asn94, Asn220, and Asn333. These sites contained varying numbers and forms of glycosyl units, suggesting sugar moieties influence PAP function. Furthermore, we found that the active sites of PAP, His44 and Asp290, are located between the two protein domains. Overall, our study not only provide an optimized approach for PAP purification, but also offer crucial insights into its structural characteristics. These findings lay the groundwork for further investigations into the physiological function and potential therapeutic applications of this important protein.

The gut microbiome dysbiosis and regulation by fecal microbiota transplantation: umbrella review.

Background: Gut microbiome dysbiosis has been implicated in various gastrointestinal and extra-gastrointestinal diseases, but evidence on the efficacy and safety of fecal microbiota transplantation (FMT) for therapeutic indications remains unclear. Methods: The gutMDisorder database was used to summarize the associations between gut microbiome dysbiosis and diseases. We performed an umbrella review of published meta-analyses to determine the evidence synthesis on the efficacy and safety of FMT in treating various diseases. Our study was registered in PROSPERO (CRD42022301226). Results: Gut microbiome dysbiosis was associated with 117 gastrointestinal and extra-gastrointestinal. Colorectal cancer was associated with 92 dysbiosis. Dysbiosis involving Firmicutes (phylum) was associated with 34 diseases. We identified 62 published meta-analyses of FMT. FMT was found to be effective for 13 diseases, with a 95.56% cure rate (95% CI: 93.88-97.05%) for recurrent Chloridoids difficile infection (rCDI). Evidence was high quality for rCDI and moderate to high quality for ulcerative colitis and Crohn's disease but low to very low quality for other diseases. Conclusion: Gut microbiome dysbiosis may be implicated in numerous diseases. Substantial evidence suggests FMT improves clinical outcomes for certain indications, but evidence quality varies greatly depending on the specific indication, route of administration, frequency of instillation, fecal preparation, and donor type. This variability should inform clinical, policy, and implementation decisions regarding FMT.

Supine transfer test-induced changes in cardiac index predict fluid responsiveness in patients without intra-abdominal hypertension.

BACKGROUND: The reversible maneuver that mimics the fluid challenge is a widely used test for evaluating volume responsiveness. However, passive leg raising (PLR) does have certain limitations. The aim of the study is to determine whether the supine transfer test could predict fluid responsiveness in adult patients with acute circulatory failure who do not have intra-abdominal hypertension, by measuring changes in cardiac index (CI). METHODS: Single-center, prospective clinical study in a 25-bed surgery intensive care unit at the Fudan University Shanghai Cancer Center. Thirty-four patients who presented with acute circulatory failure and were scheduled for fluid therapy. Every patient underwent supine transfer test and fluid challenge with 500 mL saline for 15-30 min. There were four sequential steps in the protocol: (1) baseline-1: a semi-recumbent position with the head of the bed raised to 45°; (2) supine transfer test: patients were transferred from the 45° semi-recumbent position to the strict supine position; (3) baseline-2: return to baseline-1 position; and (4) fluid challenge: administration of 500 mL saline for 15-30 min. Hemodynamic parameters were recorded at each step with arterial pulse contour analysis (ProAQT/Pulsioflex). A fluid responder was defined as an increase in CI ≥ 15% after fluid challenge. The receiver operating characteristic curve and gray zone were defined for CI. RESULTS: Seventeen patients were fluid challenge. The r value of the linear correlations was 0.73 between the supine transfer test- and fluid challenge-induced relative CI changes. The relative changes in CI induced by supine transfer in predicting fluid responsiveness had an area under the receiver operating characteristic curve of 0.88 (95% confidence interval 0.72-0.97) and predicted a fluid responder with 76.5% (95% confidence interval 50.1-93.2) sensitivity and 88.2% (95% confidence interval 63.6-98.5) specificity, at a best threshold of 5.5%. Nineteen (55%) patients were in the gray zone (CI ranging from -3 and 8 L/min/m2). CONCLUSION: The supine transfer test can potentially assist in detecting fluid responsiveness in patients with acute circulatory failure without intra-abdominal hypertension. Nevertheless, the small threshold and the 55% gray zone were noteworthy limitation. TRIAL REGISTRATION: Predicting fluid responsiveness with supine transition test (ChiCTR2200058264). Registered 2022-04-04 and last refreshed on 2023-03-26, https://www.chictr.org.cn/showproj.html?proj=166175 .

Identification of a novel bile marker clusterin and a public online prediction platform based on deep learning for cholangiocarcinoma.

BACKGROUND: Cholangiocarcinoma (CCA) is a highly aggressive malignant tumor, and its diagnosis is still a challenge. This study aimed to identify a novel bile marker for CCA diagnosis based on proteomics and establish a diagnostic model with deep learning. METHODS: A total of 644 subjects (236 CCA and 408 non-CCA) from two independent centers were divided into discovery, cross-validation, and external validation sets for the study. Candidate bile markers were identified by three proteomics data and validated on 635 clinical humoral specimens and 121 tissue specimens. A diagnostic multi-analyte model containing bile and serum biomarkers was established in cross-validation set by deep learning and validated in an independent external cohort. RESULTS: The results of proteomics analysis and clinical specimen verification showed that bile clusterin (CLU) was significantly higher in CCA body fluids. Based on 376 subjects in the cross-validation set, ROC analysis indicated that bile CLU had a satisfactory diagnostic power (AUC: 0.852, sensitivity: 73.6%, specificity: 90.1%). Building on bile CLU and 63 serum markers, deep learning established a diagnostic model incorporating seven factors (CLU, CA19-9, IBIL, GGT, LDL-C, TG, and TBA), which showed a high diagnostic utility (AUC: 0.947, sensitivity: 90.3%, specificity: 84.9%). External validation in an independent cohort (n = 259) resulted in a similar accuracy for the detection of CCA. Finally, for the convenience of operation, a user-friendly prediction platform was built online for CCA. CONCLUSIONS: This is the largest and most comprehensive study combining bile and serum biomarkers to differentiate CCA. This diagnostic model may potentially be used to detect CCA.

Phenotypic Heterogeneity Analysis of APC-Mutant Colon Cancer by Proteomics and Phosphoproteomics Identifies RAI14 as a Key Prognostic Determinant in East Asians and Westerners.

Adenomatous polyposis coli (APC) is an important tumor suppressor and is mostly linked to the regulation of the Wnt/ß-catenin signaling pathway. APC mutation has been identified as an early event in more than 80% of sporadic colorectal cancers (CRCs). Moreover, prognostic differences are observed in CRC patients with APC mutations. Although previous genomics studies have investigated the roles of concomitant gene mutations in determining the phenotypic heterogeneity of APC-mutant tumors, valuable prognostic determinants for APC-mutant CRC patients are still lacking. Based on the proteome and phosphoproteome data, we classified APC-mutant colon cancer patients and revealed genomic, proteomic, and phosphoproteomic heterogeneity in APC-mutant tumors. More importantly, we identified RAI14 as a key prognostic determinant for APC-mutant but not APC-wildtype colon cancer patients. The heterogeneity and the significance of prognostic biomarkers in APC-mutant tumors were further validated in the Clinical Proteomic Tumor Analysis Consortium (CPTAC) colon cancer cohort. In addition, we found that colon cancer patients with high expression of RAI14 were less responsive to chemotherapy. Knockdown of RAI14 in cell lines led to reduced cell migration and changes in epithelial-mesenchymal transition (EMT)-related markers. Mechanistically, knockdown of RAI14 remodeled the phosphoproteome associated with cell adhesion, which might affect EMT marker expression and promote F-actin degradation. Collectively, this work describes the phenotypic heterogeneity of APC-mutant tumors and identifies RAI14 as an important prognostic determinant for APC-mutant colon cancer patients. The prognostic utility of RAI14 in APC-mutant colon cancer will provide early warning and increase the chance of successful treatment.

Characterization of immunomodulatory factors and cells in bronchoalveolar lavage fluid for immune checkpoint inhibitor-related pneumonitis.

As immune checkpoint inhibitors (ICIs) are widely used, a series of immune-related adverse events (irAEs) have been reported, including immune checkpoint inhibitor-related pneumonitis (ICI-pneumonitis). The incidence of ICI-pneumonitis is higher in reality than in clinical trials. The diagnosis is challenging, mainly based on clinical and imaging features, and requires the exclusion of other causes. The data on the biological mechanisms of ICI-pneumonitis are scarce, resulting in little knowledge of the best treatment for ICI-pneumonitis. Bronchoalveolar lavage (BAL) may be helpful to identify the biological differences or find predictive biomarkers, and may in turn help to develop phenotype-specific targeted drugs to treat ICI-pneumonitis. Herein, we outline the characterization of immunomodulatory factors and cells in bronchoalveolar lavage fluid for ICI-pneumonitis. Through careful sorting and literature review, we find crosstalk between pathogenic Th17/Th1 cells (i.e., Th17.1) and pro-inflammatory monocytes, and activation of Th17(/Th1)/IL-17A (/IFN-γ) pathways may play a key role in the pathogenesis of ICI-pneumonitis. Disruption of the interaction between pathogenic Th17/Th1 cells and pro-inflammatory monocytes (such as, anti-IL-23) may be a potential treatment for ICI-pneumonitis. We first describe the possible pathophysiological mechanisms of ICI-pneumonitis, hoping to contribute to the optimization of diagnosis and treatment, as well as provide readers with research inspiration.

Loss of RBPMS in ovarian cancer compromises the efficacy of EGFR inhibitor gefitinib through activating HER2/AKT/mTOR/P70S6K signaling.

RBPMS may be a tumor suppressor in cancer, but its impact in modulation of drug sensitivity is unclear. This study aimed to investigate the regulatory role of RBPMS in cellular response to EGFR inhibitor gefitinib in ovarian cancer (OC). By western blotting assay, we revealed RBPMS was down-regulated in epithelial ovarian cancer tissues compared to normal control ovarian epithelial tissues. Overexpression of RBPMS inhibited cell viability and proliferation, and conferred gefitinib sensitivity, accompanied by reduced expression of p-EGFR, and vice versa. Proteomic analysis and flow cytometry experiments showed that RBPMS induced S-stage cell cycle arrest in gefitinib-treated OC cells. Co-IP assay suggested that HER2 was a downstream target of RBPMS, and RBPMS negatively regulated HER2 expression. HER2 counteracted the stimulation of RBPMS to cell growth blocking, gefitinib sensitivity and cell cycle arrest. We further demonstrated that RBPMS overexpression suppressed the activation of p-AKT, p-mTOR and p-P70S6K, which was rescued by up-regulation of HER2. The combination of AKT inhibitor MK2206 and gefitinib had a synergistic effect on OC cells with high level of RBPMS. In conclusion, through the direct inhibition of HER2/AKT/mTOR/P70S6K pathway, RBPMS may be a potential therapeutic target for improving gefitinib sensitivity in OC.

Case Report: Treatment for steroid-refractory immune-related myocarditis with tofacitinib.

Introduction: Immune therapy has ushered in a new era of tumor treatment, at the expense of immune-related adverse events, including rare but fatal adverse cardiovascular events, such as myocarditis. Steroids remain the cornerstone of therapy for immune-related myocarditis, with no clear consensus on additional immunosuppressive treatment for steroid-refractory cases yet. Case report: Here, we report a patient with stage IV nasopharyngeal carcinoma who developed immune-related myocarditis in the fourth course of therapy with immune checkpoint inhibitors. The patient presented with precordial discomfort with elevation of cardiac enzymes and interleukin-6, atypical electrocardiographic abnormalities, and reduced left ventricular ejection fraction. Coronary computed tomography angiography excluded the possibility of acute coronary syndrome. The therapy with tofacitinib targeting the Janus kinase-signal transducer and activator of transcription signal pathway was successfully conducted, since there was no significant improvement in troponin under high-dose steroid and intravenous immunoglobulin treatment. The patient recovered without major adverse cardiac events during hospitalization. Discussion: The safety and efficacy of tofacitinib in a patient with steroid-refractory immune-related myocarditis were investigated, hoping to provide a basis for prospective therapeutic strategies. Tofacitinib led to remarkable remissions in primary autoimmune disease by blocking the inflammatory cascade, indicating its potential therapeutic use in immune-related adverse events.

Phosphoproteomics reveals that cinobufotalin promotes intrahepatic cholangiocarcinoma cell apoptosis by activating the ATM/CHK2/p53 signaling pathway.

Intrahepatic cholangiocarcinoma (ICC) is a malignant tumor that originates from bile duct's epithelial cells and is usually characterized by insidious symptoms and poor prognosis. Cinobufotalin (CB), an active ingredient obtained from the Traditional Chinese Medicine ChanSu, is purported to exhibit a wide range of antitumorigenic activities. However, the mechanism by which it achieves such pharmacological effects remains elusive. Here, we disclosed the mechanism of action by which CB inhibits ICC cells. Initial experiments revealed that the proliferation of RBE and HCCC-9810 cells was significantly inhibited by CB with IC50 values of 0.342 µM and 0.421 µM respectively. CB induced the expression of caspase-3 subsequently leading to the apoptosis of ICC cells. Phosphoproteomics revealed that the phosphorylation of many proteins associated with DNA damage response increased. Kinase-substrate enrichment analysis revealed that ATM was activated after CB treatment, while CDK1 was inactivated. Activated ATM increased p-CHK2-T68 and p-p53-S15, which promoted the expression of FAS, DR4 and DR5 and triggered cell apoptosis. In summary, this work reveals the role of CB in inducing DNA damage and cell apoptosis involved in the activation of the ATM/CHK2/p53 signaling pathway, and indicates that CB may serve as a chemotherapeutic drug candidate for ICC treatment.

The diagnostic value of endoplasmic reticulum stress-related specific proteins GRP78 and CHOP in patients with sepsis: a diagnostic cohort study.

Background: Sepsis is a life-threatening disease with high mortality. Early diagnosis is critical as early treatment improves outcomes. The protein levels of glucose regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP), markers of endoplasmic reticulum stress (ERS) activation, were reported increasing rapidly and continuously in the serum of patients with sepsis. Therefore, they might serve as a potential biomarker for sepsis diagnosis. This study aimed to analyze the role of GRP78 and CHOP in the diagnosis of patients with sepsis. Methods: This study enrolled a total of 92 infected patients with or without sepsis who were admitted to the intensive care unit (ICU) from February 1, 2018 to September 30, 2018. According to 2016 SCCM/ESICM Sepsis 3.0 diagnostic criteria, patients with sepsis were allocated into group I (sepsis infected group) and patients without sepsis were allocated into group II (non-sepsis infected group). Serum samples were collected on days 1, 2, 3, and 7 after admission to ICU, and the concentrations of GRP78 and CHOP in the serum were analyzed by enzyme-linked immunosorbent assay (ELISA). The diagnostic ability of GRP78, CHOP, and other traditional inflammatory markers was assessed with receiver operating characteristic (ROC)/area under the ROC curves (AUC) analysis. Patients were shortly follow-up for the 28-day mortality. Results: Serum GRP78 and CHOP levels in group I patients were higher than that in group II patients (P=0.021, P=0.00, respectively). When GRP78 was used to diagnose sepsis, the maximum area under the ROC curve (AUC) was 0.771 (95% CI: 0.662-0.880) and the optimal threshold was 157.29 ng/L (sensitivity, 75.0%; specificity, 73.1%) on day 2. When CHOP was used for the diagnosis of sepsis, the maximum AUC was 0.813(95% CI: 0.721-0.906) and the optimal threshold was 4.915 ng/L (sensitivity, 57.7%; specificity, 96.2%) on day 2. Conclusions: Compared with traditional inflammatory markers, ERS-related specific proteins GRP78 and CHOP have better sensitivity and specificity in the diagnosis of sepsis, which is helpful for clinicians in the diagnosis of sepsis.

Changes in the Cardiac Index Induced by Unilateral Passive Leg Raising in Spontaneously Breathing Patients: A Novel Way to Assess Fluid Responsiveness.

Background: Evaluation of fluid responsiveness in intensive care unit (ICU) patients is crucial. This study was to determine whether changes in the cardiac index (CI) induced by a unilateral passive leg raising (PLR) test in spontaneously breathing patients can estimate fluid responsiveness. Methods: This was a prospective study, and 40 patients with spontaneous breathing activity who were considered for volume expansion (VE) were included. CI data were obtained in a semirecumbent position, during unilateral PLR, bilateral PLR, and immediately after VE. If the CI increased more than 15% in response to the expansion in volume, patients were defined as responders. Results: The results showed that a unilateral PLR-triggered CI increment of ≥7.5% forecasted a fluid-triggered CI increment of ≥15% with 77.3% sensitivity and 83.3% specificity with and an area under the receiver operating characteristic (ROC) curve of 0.82 [P < 0.001]. Compared with that for bilateral PLR, the area under the ROC curve constructed for unilateral PLR-triggered changes in CI (ΔCI) was not significantly different (p = 0.1544). Conclusion: ΔCI >7.5% induced by unilateral PLR may be able to predict fluid responsiveness in spontaneously breathing patients and is not inferior to that induced by bilateral PLR. Trial Registration: Unilateral passive leg raising test to assess patient volume responsiveness: Single-Center Clinical Study, ChiCTR2100046762. Registered May 28, 2021.

The stress hyperglycemia ratio, a novel index of relative hyperglycemia, predicts short-term mortality in critically ill patients after esophagectomy.

Background: Postoperative mortality and severe complications are associated with both long-term blood glucose management and the severity of stress hyperglycemia. The purpose of this study was to assess the predictive value of a novel index, the stress hyperglycemia ratio (SHR), for short-term mortality in critically ill patients following esophagectomy. Methods: A total of 356 patients who underwent esophagectomy for esophageal squamous cell carcinoma (ESCC) and were admitted to the intensive care unit (ICU) were included in this retrospective study. Based on the SHR values, patients were divided into low (SHR <1.14) or high (SHR ≥1.14) groups in the overall and diabetic populations. The major outcomes of this study were the 30- and 90-day all-cause mortalities. We used Cox proportional hazard regression, Kaplan-Meier survival analysis, and competing risk regression models to analyze the relationships between risk factors and outcomes. Results: The 30- and 90-day mortality in the high-SHR group were significantly higher compared to the low-SHR group in the total population (30-day: 1.3% vs. 10.5%, P<0.001; 90-day: 5.8% vs. 20.0%, P<0.001) and the diabetic population (30-day: 2.6% vs. 17.3%, P=0.026; 90-day: 5.1% vs. 36.5%, P<0.001). After adjusting for covariables, the risk of the 30-day mortality [1.770 (1.442, 3.170)] and 90-day mortality [1.869 (1.289, 3.409)] remained significant (P=0.035, P=0.045) in the total population. A similar result was observed in patients with diabetes [30-day: 1.642 (1.131, 2.710), P=0.015; 90-day: 2.136 (1.254, 3.946), P=0.005]. The Kaplan-Meier survival estimates for the 30-/90-day mortality also showed comparable results. The multivariable logistic regression analysis, including all glucose-related indices and the Acute Physiology and Chronic Health Evaluation (APACHE) II score, showed that SHR was independently correlated with the 30- and 90-day mortality; each 0.1-increase was related to a 3-4% elevation in the 30-/90-day mortality [odds ratio (OR), 1.044; 95% confidence interval (CI), 1.036-1.069; OR, 1.036; 95% CI, 1.021-1.051]. Conclusions: In this study, we found that a relative increase in blood glucose, as quantified by the SHR ≥1.14, was independently related to the higher 30-/90-day mortality in patients admitted to the ICU with severe complications following esophagectomy, while absolute hyperglycemia was not.

Strain parameters for predicting the prognosis of non-ischemic dilated cardiomyopathy using cardiovascular magnetic resonance tissue feature tracking.

BACKGROUND: A considerable number of non-ischemic dilated cardiomyopathy (NDCM) patients had been found to have normalized left ventricular (LV) size and systolic function with tailored medical treatments. Accordingly, we aimed to evaluate if strain parameters assessed by cardiovascular magnetic resonance (CMR) feature tracking (FT) analysis could predict the NDCM recovery. METHODS: 79 newly diagnosed NDCM patients who underwent baseline and follow-up CMR scans were enrolled. Recovery was defined as a current normalized LV size and systolic function evaluated by CMR. RESULTS: Among 79 patients, 21 (27%) were confirmed recovered at a median follow-up of 36 months. Recovered patients presented with faster heart rates (HR) and larger body surface area (BSA) at baseline (P < 0.05). Compared to unrecovered patients, recovered pateints had a higher LV apical radial strain divided by basal radial strain (RSapi/bas) and a lower standard deviation of time to peak radial strain in 16 segments of the LV (SD16-TTPRS). According to a multivariate logistic regression model, RSapi/bas (P = 0.035) and SD16-TTPRS (P = 0.012) resulted as significant predictors for differentiation of recovered from unrecovered patients. The sensitivity and specificity of RSapi/bas and SD16-TTPRS for predicting recovered conditions were 76%, 67%, and 91%, 59%, with the area under the curve of 0.75 and 0.76, respectively. Further, Kaplan Meier survival analysis showed that patients with RSapi/bas ≥ 0.95% and SD16-FTPRS ≤ 111 ms had the highest recovery rate (65%, P = 0.027). CONCLUSIONS: RSapi/bas and CMR SD16-TTPRS may be used as non-invasive parameters for predicting LV recovery in NDCM. This finding may be beneficial for subsequent treatments and prognosis of NDCM patients. Registration number: ChiCTR-POC-17012586.

Tratamiento endovascular de aneurisma gigante de aorta abdominal / Endovascular exclusion for giant abdominal aortic aneurysm

No disponible

Evaluation of elevated left ventricular end diastolic pressure in patients with preserved ejection fraction using cardiac magnetic resonance.

OBJECTIVES: This study aims to validate the reliability of cardiac magnetic resonance (CMR) parameters for estimating left ventricular end diastolic pressure (LVEDP) in heart failure patients with preserved ejection fraction (HFpEF) and compare their accuracy to conventional echocardiographic ones, with reference to left heart catheterisation. METHODS: Sixty patients with exertional dyspnoea (New York Heart Association function class II to III) were consecutively enrolled. CMR-derived time-volume curve and deformation parameters, conventional echocardiographic diastolic indices as well as LVEDP evaluated by left heart catheterisation were collected and analysed. RESULTS: Fifty-one patients, who accomplished all three examinations, were divided into HFpEF group and non-HFpEF group based on LVEDP measurements. Compared to the non-HFpEF group, CMR-derived time-volume curve showed lower peak filling rate adjusted for end diastolic volume (PFR/EDV, p = 0.027), longer time to peak filling rate (T-PFR, p < 0.001), and increased T-PFR in one cardiac cycle (%T-PFR, p < 0.001) in HFpEF group. In multivariable linear regression analysis, %T-PFR (ß = 0.372, p = 0.024), left ventricular global peak longitudinal diastolic strain rate (LDSR, ß = -0.471, p = 0.006), and E/e' (ß = 0.547, p = 0.001) were independently associated with invasively measured LVEDP. The sensitivity and specificity of E/e' and LDSR for predicting the elevated LVEDP were 76%, 92% and 76%, 89%, respectively. CONCLUSIONS: These findings suggest that CMR-derived time-volume curve and strain indices could predict HFpEF patients. Not only E/e' assessed by echocardiography but also the CMR-derived %T-PFR and LDSR correlated well with LVEDP. These non-invasive parameters were validated to evaluate the left ventricular diastolic function. KEY POINTS: • The abnormal time-volume curve revealed insufficient early diastole in HFpEF patients. • Non-invasive parameters including E/e', %T-PFR, and LDSR correlated well with LVEDP.

Quercetin inhibits human sperm functions by reducing sperm [Ca2+]i and tyrosine phosphorylation.

Quercetin is widely known as potent natural antioxidant and scavenger of reactive oxygen species (ROS) and nitric oxide both in vitro and in vivo. Quercetin has a wide range of biological functions and health-promoting effects. There are more and more interests in the addition of this flavonol to various traditional food products. However, the in vitro toxicity of quercetin to mature human sperm remains unknown. In this study, we investigated the in vitro effects of quercetin on human sperm functions. The results showed that the total sperm motility were significantly inhibited compared to the controls following exposure to 100, 200 and 400µM quercetin for 6 and 12h; quercetin did not affect human sperm viability. The acrosome reaction and capacitation induced by progesterone were dose-dependently inhibited by quercetin. Furthermore, quercetin induced a significantly decrease of human sperm [Ca2+]i after 2 min above 50 µM, and dose-dependently decreased the protein-tyrosine phosphorylation of human sperm. Our results indicated that quercetin may decrease sperm [Ca2+]i, suppresse tyrosine phosphorylation, and subsequently inhibit sperm functions.