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1.
World J Surg Oncol ; 21(1): 372, 2023 Nov 29.
Article in English | MEDLINE | ID: mdl-38031044

ABSTRACT

BACKGROUND: Perineural invasion (PNI) is regarded as a prognostic factor for patients with GC. However, the significance of PNI in patients with stage II GC remains unclear. This study aimed to investigate the clinical implication of PNI in patients with stage II GC undergoing curative resection. METHODS: Patients with stage II GC who underwent curative resection were retrospectively evaluated from January 2010 to July 2019. According to PNI status, all patients were divided into two groups: with or without PNI. The prognostic value of PNI was analyzed by univariate and multivariate Cox proportional hazards regression models. RESULTS: A total of 233 patients were included in this study. There were 100 patients with PNI (42.92%) and 133 patients without PNI (57.08%). The overall survival (OS) and disease-free survival (DFS) rates for patients with PNI were significantly lower than that for patients without PNI (p = 0.019 and p = 0.032, respectively). Multivariate analysis indicated that the presence of PNI was an independent risk factor for OS (hazard ratio (HR): 1.76, 95% confidence interval (CI) 1.02-3.06, p = 0.044) and DFS (HR: 1.70, 95% CI 1.04-2.80, p = 0.035), while adjuvant chemotherapy (AC) was an independent protective factor for OS (HR: 0.51, 95% CI 0.30-0.88, p = 0.016) and DFS (HR: 0.52, 95% CI 0.31-0.86, p = 0.011). Furthermore, among patients with PNI, those who received AC had better OS (p = 0.022) and DFS (p = 0.027) than their counterparts. When patients with PNI received AC, the OS (p = 0.603) and DFS (p = 0.745) appeared to be similar to those without PNI and no AC. CONCLUSION: In patients with stage II GC undergoing curative resection, the presence of PNI was associated with worse survival, which appeared to improve with the treatment of AC, indicating a potential need for more intensive AC.


Subject(s)
Stomach Neoplasms , Humans , Stomach Neoplasms/surgery , Retrospective Studies , Peripheral Nerves , Prognosis , Disease-Free Survival , Neoplasm Invasiveness
3.
Exp Mol Med ; 54(6): 834-847, 2022 06.
Article in English | MEDLINE | ID: mdl-35760875

ABSTRACT

Esophageal squamous cell carcinoma (ESCC) is one of the most life- and health-threatening malignant diseases worldwide, especially in China. Long noncoding RNAs (lncRNAs) have emerged as important regulators of tumorigenesis and tumor progression. However, the roles and mechanisms of lncRNAs in ESCC require further exploration. Here, in combination with a small interfering RNA (siRNA) library targeting specific lncRNAs, we performed MTS and Transwell assays to screen functional lncRNAs that were overexpressed in ESCC. TMPO-AS1 expression was significantly upregulated in ESCC tumor samples, with higher TMPO-AS1 expression positively correlated with shorter overall survival times. In vitro and in vivo functional experiments revealed that TMPO-AS1 promotes the proliferation and metastasis of ESCC cells. Mechanistically, TMPO-AS1 bound to fused in sarcoma (FUS) and recruited p300 to the TMPO promoter, forming biomolecular condensates in situ to activate TMPO transcription in cis by increasing the acetylation of histone H3 lysine 27 (H3K27ac). Targeting TMPO-AS1 led to impaired ESCC tumor growth in a patient-derived xenograft (PDX) model. We found that TMPO-AS1 is required for cell proliferation and metastasis in ESCC by promoting the expression of TMPO, and both TMPO-AS1 and TMPO might be potential biomarkers and therapeutic targets in ESCC.


Subject(s)
Esophageal Neoplasms , Esophageal Squamous Cell Carcinoma , Gene Expression Regulation, Neoplastic , MicroRNAs , RNA, Long Noncoding , RNA-Binding Protein FUS , Thymopoietins , Biomolecular Condensates , Cell Line, Tumor , Cell Proliferation , Disease Progression , Esophageal Neoplasms/genetics , Esophageal Squamous Cell Carcinoma/genetics , Esophageal Squamous Cell Carcinoma/metabolism , Esophageal Squamous Cell Carcinoma/pathology , Humans , MicroRNAs/genetics , Nuclear Proteins/metabolism , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , RNA, Small Interfering , Thymopoietins/genetics , Thymopoietins/metabolism
4.
Cancer Res ; 81(10): 2636-2650, 2021 05 15.
Article in English | MEDLINE | ID: mdl-33782099

ABSTRACT

Long noncoding RNAs (lncRNA) are involved in tumorigenesis and drug resistance. However, the roles and underlying mechanisms of lncRNAs in colorectal cancer are still unknown. In this work, through transcriptomic profiling analysis of 21 paired tumor and normal samples, we identified a novel colorectal cancer-related lncRNA, MNX1-AS1. MNX1-AS1 expression was significantly upregulated in colorectal cancer and associated with poor prognosis. In vitro and in vivo gain- and loss-of-function experiments showed that MNX1-AS1 promotes the proliferation of colorectal cancer cells. MNX1-AS1 bound to and activated Y-box-binding protein 1 (YB1), a multifunctional RNA/DNA-binding protein, and prevented its ubiquitination and degradation. A marked overlap between genes that are differentially expressed in MNX1-AS1 knockdown cells and transcriptional targets of YB1 was observed. YB1 knockdown mimicked the loss of viability phenotype observed upon depletion of MNX1-AS1. In addition, MYC bound the promoter of the MNX1-AS1 locus and activated its transcription. In vivo experiments showed that ASO inhibited MNX1-AS1, which suppressed the proliferation of colorectal cancer cells in both cell-based and patient-derived xenograft models. Collectively, these findings suggest that the MYC-MNX1-AS1-YB1 axis might serve as a potential biomarker and therapeutic target in colorectal cancer. SIGNIFICANCE: This study highlights the discovery of a novel colorectal cancer biomarker and therapeutic target, MNX1-AS1, a long noncoding RNA that drives proliferation via a MYC/MNX1-AS1/YB1 signaling pathway. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/10/2636/F1.large.jpg.


Subject(s)
Colorectal Neoplasms/pathology , Gene Expression Regulation, Neoplastic , Homeodomain Proteins/genetics , Proto-Oncogene Proteins c-myc/metabolism , RNA, Antisense/genetics , RNA, Long Noncoding/genetics , Transcription Factors/genetics , Y-Box-Binding Protein 1/chemistry , Animals , Apoptosis , Cell Proliferation , Colorectal Neoplasms/genetics , Colorectal Neoplasms/metabolism , Disease Progression , Female , Humans , Mice , Mice, Inbred BALB C , Mice, Nude , Prognosis , Proto-Oncogene Proteins c-myc/genetics , Survival Rate , Tumor Cells, Cultured , Xenograft Model Antitumor Assays , Y-Box-Binding Protein 1/genetics , Y-Box-Binding Protein 1/metabolism
5.
Cancer Med ; 10(7): 2423-2441, 2021 04.
Article in English | MEDLINE | ID: mdl-33666372

ABSTRACT

BACKGROUND: Numerous reports on microRNAs have illustrated their role in tumor growth and metastasis. Recently, a new prognostic factor, miR-125b-2-3p, has been identified for predicting chemotherapeutic sensitivity in advanced colorectal cancer (CRC). However, the specific mechanisms and biological functions of miR-125b-2-3p in advanced CRC under chemotherapy have yet to be elucidated. METHODS: MiR-125b-2-3p expression was detected by real-time PCR (RT-PCR) in CRC tissues. The effects of miR-125b-2-3p on the growth, metastasis, and drug sensitivity of CRC cells were tested in vitro and in vivo. Based on multiple databases, the upstream competitive endogenous RNAs (ceRNAs) and the downstream genes for miR-125b-2-3p were predicted by bioinformatic analysis, followed by the experiments including luciferase reporter assays, western blot assays, and so on. RESULTS: MiR-125b-2-3p was significantly lowly expressed in the tissues and cell lines of CRC. Higher expression of miR-125b-2-3p was associated with relatively lower proliferation rates and fewer metastases. Moreover, overexpressed miR-125b-2-3p remarkably improved chemotherapeutic sensitivity of CRC in vivo and in vitro. Mechanistically, miR-125b-2-3p was absorbed by long noncoding RNA (lncRNA) XIST regulating WEE1 G2 checkpoint kinase (WEE1) expression. The upregulation of miR-125b-2-3p inhibited the proliferation and epithelial-mesenchymal transition (EMT) of CRC induced by lncRNA XIST. CONCLUSIONS: Lower miR-125b-2-3p expression resulted in lower sensitivity of CRC to chemotherapy and was correlated with poorer survival of CRC patients. LncRNA XIST promoted CRC metastasis acting as a ceRNA for miR-125b-2-3p to mediate WEE1 expression. LncRNA XIST-miR-125b-2-3p-WEE1 axis not only regulated CRC growth and metastasis but also contributed to chemotherapeutic resistance to CRC.


Subject(s)
Cell Cycle Proteins/metabolism , Colorectal Neoplasms/metabolism , Drug Resistance, Neoplasm , MicroRNAs/metabolism , Protein-Tyrosine Kinases/metabolism , RNA, Long Noncoding/metabolism , Aged , Animals , Antineoplastic Agents/therapeutic use , Cell Cycle Proteins/genetics , Cell Line, Tumor , Cell Proliferation/genetics , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Drug Resistance, Neoplasm/genetics , Epithelial-Mesenchymal Transition/genetics , Female , HCT116 Cells , Humans , Male , Mice , Mice, Inbred BALB C , Mice, Nude , MicroRNAs/genetics , Middle Aged , Neoplasm Metastasis/genetics , Protein-Tyrosine Kinases/genetics , Real-Time Polymerase Chain Reaction , Tumor Stem Cell Assay , Up-Regulation
6.
Trends Mol Med ; 27(5): 482-500, 2021 05.
Article in English | MEDLINE | ID: mdl-33500194

ABSTRACT

Liquid biopsies, in particular, analysis of cell-free DNA (cfDNA), have emerged as a promising noninvasive diagnostic approach in oncology. Abnormal distribution of DNA methylation is one of the hallmarks of many cancers and methylation changes occur early during carcinogenesis. Systemic analysis of cfDNA methylation profiles is being developed for cancer early detection, monitoring for minimal residual disease (MRD), predicting treatment response and prognosis, and tracing the tissue origin. This review highlights the advantages and disadvantages of ctDNA profiling for noninvasive diagnosis of early-stage cancers and explores recent advances in the clinical application of ctDNA methylation assays. We also summarize the technologies for ctDNA methylation analysis and provide a brief overview of the bioinformatic approaches for analyzing DNA methylation sequencing data.


Subject(s)
Biomarkers, Tumor , Circulating Tumor DNA , DNA Methylation , Liquid Biopsy , Neoplasms , Biomarkers, Tumor/blood , Biomarkers, Tumor/genetics , Cell-Free Nucleic Acids/genetics , Circulating Tumor DNA/genetics , Circulating Tumor DNA/isolation & purification , Computational Biology/methods , DNA Fingerprinting/methods , Early Detection of Cancer , Humans , Neoplasms/diagnosis , Neoplasms/genetics , Prognosis
7.
Mol Ther ; 29(2): 587-596, 2021 02 03.
Article in English | MEDLINE | ID: mdl-33333293

ABSTRACT

The therapeutic strategies of stage II/III colorectal cancer (CRC) patients after curative surgery remain controversial. In the clinical decision-making process, oncologists need to answer questions such as whether adjuvant chemotherapy is necessary or which therapeutic regimen should be given to each patient. At present, whether adjuvant chemotherapy should be applied is primarily based on histopathological features and clinical risk factors. However, only a fraction of patients can benefit from it. More rigorous stratifying biomarkers are urgently needed to help further distinguishing these populations of patients. Recent progress in next-generation sequencing and high-throughput technologies has greatly promoted biomarker discovery as well as our understanding of the underlying mechanisms in CRC. Novel genetic and epigenetic biomarkers that are associated with prognosis or therapeutic responses have emerged. In this review, we discuss the strategies of biomarker discovery and summarize the status and assess the utility of previously published biomarkers in CRC.


Subject(s)
Biomarkers, Tumor , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/genetics , Epigenesis, Genetic , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Chemotherapy, Adjuvant , Colorectal Neoplasms/mortality , Genomics/methods , Humans , Neoplasm Staging , Prognosis , Treatment Outcome
8.
Cancer Manag Res ; 11: 4719-4728, 2019.
Article in English | MEDLINE | ID: mdl-31213896

ABSTRACT

Purpose: The inflammatory microenvironment and hemostatic system are involved in several stages of tumor progression. The aim of this study was to assess the prognostic effect of fibrinogen-to-lymphocyte ratio (FLR) in esophageal squamous cell carcinoma (ESCC) patients who underwent radical esophagectomy. Patients and methods: We retrospectively reviewed 673 consecutive patients with ESCC who underwent radical esophagectomy from January 2009 to December 2012 at a major cancer hospital in Guangzhou, southern China. The cutoff points were defined by the X-tile software. The prognostic value of FLR for overall survival (OS), disease-free survival (DFS), and first-year mortality after surgery were analyzed using Cox proportional hazard regression model and logistic regression model. Survival was estimated by the Kaplan-Meier estimator and compared using the log-rank test. Results: The optimal cutoff point of FLR was 3.03. Compared with the FLR-low (≤3.03) group, the FLR-high (>3.03) group included older patients (χ2=7.267, P=0.007), showed higher postoperative overall morbidity (24.7% vs 14.8%, χ2=5.414, P=0.020) and tended to die within one year (23.5% vs 10.9%, χ2=10.871, P=0.001). The FLR-high group showed significant lower 5-year OS rates (41.2% vs 53.7%, log-rank=6.827, P=0.009) and 5-year DFS rates (35.3% vs 48.0%, log-rank=5.954, P=0.015) than the FLR-low group. Multivariate analyses suggested that high FLR was an independent negative predictor of OS (HR: 1.448, 95%CI: 1.073-1.952, P=0.015), DFS (HR: 1.445, 95%CI: 1.084-1.925, P=0.012) and first-year mortality (HR: 2.123, 95%CI: 1.157-3.898, P=0.015). Conclusion: The preoperative FLR level could be used as a simple, noninvasive, inexpensive, and potentially effective indicator to evaluate the prognosis of ESCC patients following radical esophagectomy.

9.
Interact Cardiovasc Thorac Surg ; 29(3): 434-441, 2019 09 01.
Article in English | MEDLINE | ID: mdl-31135037

ABSTRACT

OBJECTIVES: Our goal was to compare short- and long-term outcomes between 3-field lymphadenectomy (3-FL) and modern 2-field lymphadenectomy (2-FL) in patients with thoracic oesophageal squamous cell carcinoma. METHODS: We reviewed clinical outcomes for 298 patients with thoracic oesophageal squamous cell carcinoma who underwent 3-FL or modern 2-FL from March 2008 to December 2013 at a major cancer hospital in Guangzhou, southern China. Propensity score matching was used to balance baseline differences, and 83 pairs of cases were selected. Postoperative complications, recurrence patterns and survival outcomes were compared between the 2 groups. RESULTS: Compared with modern 2-FL, 3-FL led to higher overall operative morbidity rates [78.3% vs 61.4%, odds ratio (OR) 2.266, 95% confidence interval (CI) 1.143-4.490; P = 0.019], with higher recurrent nerve palsy rates (47.0% vs 19.3%, OR 3.712, 95% CI 1.852-7.438; P < 0.0001), more respiratory failures (18.1% vs 6.0%, OR 3.441, 95% CI 1.189-9.963; P = 0.023) and longer postoperative hospital stays (23 vs 17 days, P = 0.002). The 5-year overall survival rate (58.5% vs 59.4%; P = 0.960) and the 5-year disease-free survival rate 50.1% vs 54.5%; P = 0.482) were comparable between the 2 groups. Multivariable analysis showed that additional cervical lymph node dissection was not associated with overall survival [hazard ratio (HR) 1.039, 95% CI 0.637-1.696; P = 0.878] and disease-free survival (HR 0.868, 95% CI 0.548-1.376; P = 0.547). The overall recurrence rate and cervical nodal recurrence rate were not significantly different between the 2 groups. CONCLUSIONS: Additional cervical lymphadenectomy did not lead to added survival benefit when compared with modern 2-FL in patients with thoracic oesophageal squamous cell carcinoma. Recurrence was similar in patients undergoing 3-FL and modern 2-FL. 3-FL resulted in more postoperative complications.


Subject(s)
Esophageal Neoplasms/surgery , Esophageal Squamous Cell Carcinoma/surgery , Esophagectomy/methods , Neck Dissection/methods , Postoperative Complications/epidemiology , Propensity Score , China/epidemiology , Disease-Free Survival , Esophageal Neoplasms/mortality , Esophageal Neoplasms/pathology , Esophageal Squamous Cell Carcinoma/mortality , Esophageal Squamous Cell Carcinoma/secondary , Female , Follow-Up Studies , Humans , Incidence , Lymphatic Metastasis , Male , Middle Aged , Survival Rate/trends , Time Factors
10.
World J Urol ; 37(5): 823-829, 2019 May.
Article in English | MEDLINE | ID: mdl-30191393

ABSTRACT

PURPOSE: To assess the efficacy of intra-arterial chemotherapy (IAC) combined with intravesical chemotherapy (IVC) in T1G3 bladder cancer (Bca) after transurethral resection of bladder tumor (TURBT). METHODS: Our study retrospectively reviewed 200 patients with T1G3 BCa who had all undergone TURBT. The patients' medical records were divided into two groups, one group only had IVC with pirarubicin after surgery, and the other group had IAC (cisplatin and epirubicin) combined with IVC after surgery. The patients were monitored regularly by urine cytology and cystoscopy. Survival and recurrence curves were calculated using the Kaplan-Meier method. Tumor recurrence, progression and tumor-specific death rate were compared with Chi-square test. A multivariate analysis was carried out to find out potential confounders. RESULTS: A total of 200 medical record was analyzed, 131 patients received IVC, 69 IAC + IVC treatment, tumor-specific death rate between the combined IAC and IVC compared to IVC alone was 7.25 and 17.6%, respectively (p < 0.05); the tumor recurrence rate between the two groups was 31.8% (22/69) and 44.3%, respectively (58/131) (p < 0.05), and tumor recurred later in the IAC + IVC group (p < 0.05), tumor progression rate was 18.8% (13/69) and 28.2% (37/131), respectively, with p < 0.05. Overall survival was longer in IAC + IVC group (p < 0.05). Using the multivariable regression model, IAC was significantly related to disease recurrence (p < 0.05) and overall survival (p < 0.05). CONCLUSION: T1G3 BCa post-TURBT surgery patients who underwent IAC combined with IVC had a longer overall survival and increased time interval to first recurrence, lower tumor recurrence rate, progression rate and tumor-specific death rate than compared with those who only underwent IVC alone.


Subject(s)
Antineoplastic Agents/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Carcinoma, Transitional Cell/drug therapy , Cystoscopy , Doxorubicin/analogs & derivatives , Urinary Bladder Neoplasms/drug therapy , Administration, Intravesical , Adult , Aged , Aged, 80 and over , Chemotherapy, Adjuvant , Cisplatin/administration & dosage , Doxorubicin/therapeutic use , Epirubicin/administration & dosage , Female , Humans , Injections, Intra-Arterial , Male , Middle Aged , Neoplasm Recurrence, Local/epidemiology , Organ Sparing Treatments , Retrospective Studies , Treatment Outcome
11.
J Cancer Res Clin Oncol ; 145(2): 487-494, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30539282

ABSTRACT

OBJECTIVE: Comparing intra-arterial chemotherapy combined with intravesical chemotherapy against intravesical chemotherapy alone in the treatment of T1-staged Grade 3 (T1G3) bladder cancer after transurethral resection of bladder tumor (TURBT). MATERIALS AND METHODS: From January 2007 to December 2012, 203 patients diagnosed with NMIBC were randomly assigned into either intra-arterial chemotherapy combined with intravesical chemotherapy group (Group A, n = 68) or intravesical chemotherapy alone group (Group B, n = 135) after TURBT. Four cycles of intra-arterial chemotherapy were administered after initial TURBT with 1-month interval between each. Intravesical chemotherapy was administered in both groups including an immediate 50 mg epirubicin instillation after TURBT and weekly maintenance for 8 weeks, and then followed by monthly maintenance for 1 year. The primary endpoint was recurrence-free survival. RESULTS: Out of 203 patients, 53 were in Group A and 98 in Group B, and they were evaluated for recurrence and progression rate where recurrence rate was 35.8% (19/53) in group A and 41.8% (41/98) in group B with a significant difference (P < 0.05) and progression rate was 20.7% (11/53) in group A and 23.5% (23/98) in group B with a significant difference (P < 0.05). Univariate and multivariate logistic regression analysis suggested that intra-arterial chemotherapy could be an independent risk factors related to both overall survival and time to first recurrence. CONCLUSIONS: Intra-arterial chemotherapy combined with intravesical chemotherapy could reduce the risk of recurrence and progression compared to intravesical chemotherapy alone in T1G3 bladder cancer.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Muscle Neoplasms/drug therapy , Neoplasm Recurrence, Local/drug therapy , Urinary Bladder Neoplasms/drug therapy , Administration, Intravesical , Adult , Aged , Aged, 80 and over , Chemotherapy, Adjuvant , Cisplatin/administration & dosage , Epirubicin/administration & dosage , Female , Follow-Up Studies , Humans , Injections, Intra-Arterial , Male , Middle Aged , Muscle Neoplasms/pathology , Muscle Neoplasms/surgery , Neoplasm Grading , Neoplasm Invasiveness , Neoplasm Recurrence, Local/pathology , Neoplasm Recurrence, Local/surgery , Neoplasm Staging , Survival Rate , Urinary Bladder Neoplasms/pathology , Urinary Bladder Neoplasms/surgery
12.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 41(2): 197-205, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26932219

ABSTRACT

Next generation sequencing (NGS) has developed very rapidly in the last decade. Compared with Sanger sequencing, NGS has the advantages of high sensitivity and high throughput. Movement disorders are a common type of neurological disease. Although traditional linkage analysis has become a standard method to identify the pathogenic genes in diseases, it is getting difficult to find new pathogenic genes in rare Mendelian disorders, such as movement disorders, due to a lack of appropriate families with high penetrance or enough affected individuals. Thus, NGS is an ideal approach to identify the causal alleles for inherited disorders. NGS is used to identify genes in several diseases and new mutant sites in Mendelian movement disorders. This article reviewed the recent progress in NGS and the use of NGS in Mendelian movement disorders from genome sequencing and transcriptome sequencing. A perspective on how NGS could be employed in rare Mendelian disorders is also provided.


Subject(s)
High-Throughput Nucleotide Sequencing/methods , Movement Disorders/diagnosis , Alleles , Genetic Linkage , Humans , Movement Disorders/genetics , Sequence Analysis, DNA , Transcriptome
13.
Am J Physiol Heart Circ Physiol ; 299(6): H1843-53, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20889840

ABSTRACT

Defects in excitation-contraction coupling have been reported in failing hearts, but little is known about the relationship between these defects and the development of heart failure (HF). We compared the early changes in intracellular Ca(2+) cycling to those that underlie overt pump dysfunction and arrhythmogenesis found later in HF. Laser-scanning confocal microscopy was used to measure Ca(2+) transients in myocytes of intact hearts in Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs) at different ages. Early compensatory mechanisms include a positive inotropic effect in SHRs at 7.5-9 mo compared with 6 mo. Ca(2+) transient duration increased at 9 mo in SHRs, indicating changes in Ca(2+) reuptake during decompensation. Cell-to-cell variability in Ca(2+) transient duration increased at 7.5 mo, decreased at 9 mo, and increased again at 22 mo (overt HF), indicating extensive intercellular variability in Ca(2+) transient kinetics during disease progression. Vulnerability to intercellular concordant Ca(2+) alternans increased at 9-22 mo in SHRs and was mirrored by a slowing in Ca(2+) transient restitution, suggesting that repolarization alternans and the resulting repolarization gradients might promote reentrant arrhythmias early in disease development. Intercellular discordant and subcellular Ca(2+) alternans increased as early as 7.5 mo in SHRs and may also promote arrhythmias during the compensated phase. The incidence of spontaneous and triggered Ca(2+) waves was increased in SHRs at all ages, suggesting a higher likelihood of triggered arrhythmias in SHRs compared with WKY rats well before HF develops. Thus serious and progressive defects in Ca(2+) cycling develop in SHRs long before symptoms of HF occur. Defective Ca(2+) cycling develops early and affects a small number of myocytes, and this number grows with age and causes the transition from asymptomatic to overt HF. These defects may also underlie the progressive susceptibility to Ca(2+) alternans and Ca(2+) wave activity, thus increasing the propensity for arrhythmogenesis in HF.


Subject(s)
Arrhythmias, Cardiac/etiology , Calcium Signaling , Heart Failure/etiology , Hypertension/complications , Myocytes, Cardiac/metabolism , Age Factors , Aging , Animals , Arrhythmias, Cardiac/metabolism , Arrhythmias, Cardiac/physiopathology , Cardiac Pacing, Artificial , Disease Models, Animal , Disease Progression , Electrophysiologic Techniques, Cardiac , Excitation Contraction Coupling , Heart Failure/metabolism , Heart Failure/physiopathology , Hypertension/metabolism , Hypertension/physiopathology , Kinetics , Male , Membrane Potentials , Microscopy, Confocal , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Sarcoplasmic Reticulum/metabolism
14.
J Pharmacol Exp Ther ; 331(2): 382-91, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19675298

ABSTRACT

Pathological conditions, including ischemia and heart failure, are associated with altered sodium channel function and increased late sodium current (I(Na,L)), leading to prolonged action potential duration, increased intracellular sodium and calcium concentrations, and arrhythmias. We used anemone toxin (ATX)-II to study the effects of increasing I(Na,L) on intracellular calcium cycling in rat isolated hearts. Cardiac contraction was abolished using paralytic agents. Ranolazine (RAN) was used to inhibit late I(Na). Hearts were loaded with fluo-4-acetoxymethyl ester, and myocyte intracellular calcium transients (CaTs) were measured using laser scanning confocal microscopy. ATX (1 nM) prolonged CaT duration at 50% recovery in hearts paced at a basal rate of 2 Hz and increased the sensitivity of the heart to the development of calcium alternans caused by fast pacing. ATX increased the time required for recovery of CaT amplitude following a previous beat, and ATX induced spontaneous calcium release waves during rapid pacing of the heart. ATX prolonged the duration of repolarization from the initiation of the activation to terminal repolarization in the pseudo-electrocardiogram. All actions of ATX were both reversed and prevented by subsequent or prior exposure, respectively, of hearts to RAN (10 microM). Most importantly, the increased vulnerability of the heart to the development of calcium alternans during rapid pacing was reversed or prevented by 10 microM RAN. These results suggest that enhancement of I(Na,L) alters calcium cycling. Reduction by RAN of I(Na,L)-induced dysregulation of calcium cycling could contribute to the antiarrhythmic actions of this agent in both reentrant and triggered arrhythmias.


Subject(s)
Acetanilides/pharmacology , Calcium Signaling/drug effects , Calcium/metabolism , Enzyme Inhibitors/pharmacology , Heart/drug effects , Piperazines/pharmacology , Sodium Channels/drug effects , Algorithms , Animals , Cardiac Pacing, Artificial , Cnidarian Venoms/pharmacology , Electric Stimulation , Electrophysiology , Female , In Vitro Techniques , Male , Microscopy, Confocal , Myocardium/metabolism , Neurotoxins/pharmacology , Ranolazine , Rats , Rats, Sprague-Dawley
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