Browsing by Author "Lin, Jiunn-Lee"

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Altered expression of FHL1, CARP, TSC-22 and P311 provide insights into complex transcriptional regulation in pacing-induced atrial fibrillation
(2007-03-01)
Chen, Chien-Lung
;
Lin, Jiunn-Lee
;
Lai, Ling-Ping
;
Pan, Chun-Hsu
;
Huang, Shoei K. Stephen
Atrial fibrillation (AF) is the most common progressive disease in patients with cardiac arrhythmia. AF is accompanied by complex atrial remodeling and changes in gene expression, but only a limited number of transcriptional regulators have been identified. Using a low-density cDNA array, we identified 31 genes involved in transcriptional regulation, signal transduction or structural components, which were either significantly upregulated or downregulated in porcine atria with fibrillation (induced by rapid atrial pacing at a rate of 400-600 bpm for 4 weeks that was then maintained without pacing for 2 weeks). The genes for four and a half LIM domains protein-1 (FHL1), transforming growth factor-beta (TGF-beta)-stimulated clone 22 (TSC-22), and cardiac ankyrin repeat protein (CARP) were significantly upregulated, and chromosome 5 open reading frame gene 13 (P311) was downregulated in the fibrillating atria. FHL1 and CARP play important regulatory roles in cardiac remodeling by transcriptional regulation and myofilament assembly. Induced mRNA expression of both FHL1 and CARP was also observed when cardiac H9c2 cells were treated with an adrenergic agonist. Increasing TSC-22 and marked P311 deficiency could enhance the activity of TGF-beta signaling and the upregulated TGF-beta 1 and -beta 2 expressions were identified in the fibrillating atria. These results implicate that observed alterations of underlying molecular events were involved in the rapid-pacing induced AF, possibly via activation of the beta-adrenergic and TGF-beta signaling. (c) 2006 Elsevier B.V. All rights reserved.
Anti-Hyperglycemic Agents and New-Onset Acute Myocardial Infarction in Diabetic Patients with End-Stage Renal Disease Undergoing Dialysis
(2016-08-11)
Lin, Ting-Tse
;
Wu, Chih-Chen
;
Yang, Yao-Hsu
;
Lin, Lian-Yu
;
Lin, Jiunn-Lee
Background Diabetes and chronic kidney disease (CKD) are a high-stakes combination for cardiovascular disease. Patients with decreased kidney function and end-stage renal disease ( ESRD) have increased risk of hypoglycemia when attaining better glycemic control, leading to higher risk of myocardial infarction (MI). For these patients, which kinds of anti-hyperglycemic agents would be associated with higher risk of MI is not clear. Methods We identified patients from a nation-wide database called Registry for Catastrophic Illness, which encompassed almost 100% of the patients receiving dialysis therapy in Taiwan from 1995 to 2008. Patients with diabetes and ESRD were selected as the study cohort. Propensity score adjustment and Cox's proportional hazards regression model were used to estimate the hazard ratios (HRs) for new-onset MI. Results Among 15,161 patients, 39% received insulin, 40% received sulfonylureas, 18% received meglitinides and 3% received thiazolidinedione (TZD). After a median follow-up of 1,357 days, the incidence of MI was significant increase in patients taking sulfonylureas (HR =1.523, 95% confidence interval [CI]=1.331-1.744), meglitinides ( HR=1.251, 95% CI=1.048-1.494) and TZD (HR=1.515, 95% CI=1.071-2.145) by using patients receiving insulin therapy as the reference group. The risk of MI remains higher in other three groups in subgroup analyses. Conclusions In conclusion, among diabetic patients with ESRD undergoing dialysis, the use of sulfonylureas, meglitinides and TZD are associated with higher risk of new-onset MI as compared with insulin.
Downregulation of angiotensin converting enzyme II is associated with pacing-induced sustained atrial fibrillation
(2007-02-06)
Pan, Chun-Hsu
;
Lin, Jiunn-Lee
;
Lai, Ling-Ping
;
Chen, Chien-Lung
;
Huang, Shoei K. Stephen
Atrial fibrillation (AF), the most common cardiac arrhythmia, is frequently accompanied by atrial interstitial fibrosis. Angiotensin II (Ang II) dependent signaling pathways have been implicated in interstitial fibrosis during the development of AF. However, Ang II could be further degraded by angiotensin converting enzyme II (ACE2). We examined expression of ACE2 in the fibrillating atria of pigs and its involvement in fibrotic pathogenesis during AF. Nine adult pigs underwent continuous rapid atrial pacing to induce sustained AF and six pigs were sham controls (i.e., sinus rhythm; SR). In the histological examinations, extensive accumulation of extracellular matrix in the interstitial space of the atria, as evidenced by Masson's trichrome stain, were found in fibrillating atria. The relative amount of collagen type I in the atria with AF was significantly increased as compared with that in the SR. Local ACE activity in the fibrillating atria was also markedly higher than that in the SR subjects. ACE2 gene and protein expression in the AF subjects were significantly decreased compared with those in the SR subjects, whereas expression of mitogen-activated/ERK kinase 1/2 (MEK1/2), extracellular signal-regulated protein kinase 2 (ERK2), and activated ERK2 were significantly greater in the AF subjects. We propose that decreasing ACE2 expression during AF may affect the Ang II-dependent signaling pathway. In addition, our results suggest that atrial fibrosis in AF may be induced by antagonistic regulation between ACE and ACE2 expression. (c) 2007 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.
Increased expression of extracellular matrix proteins in rapid atrial pacing-induced atrial fibrillation
(2007-07-01)
Lin, Chih-Sheng
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Lai, Ling-Ping
;
Lin, Jiunn-Lee
;
Sun, Yu-Ling
;
Hsu, Chih-Wei
BACKGROUND: Atria[ fibrillation (AF) is characterized by structural remodeling of the extracellular matrix (ECM) in cardiac atrium. OBJECTIVE: The purpose of this study was to gain further insight into atrial ECM remodeling at the molecular Level and to test whether altered expression of ECM proteins was associated with the disease. METHODS: Sustained AF was induced in nine adult pigs after 3-4 weeks of continuous rapid atrial pacing at a rate of 600 bpm. Histologic studies and immunohistochemical stain were performed to identify the potential pathologic substrate underlying abnormalities in atrial tissues with sustained AF. RESULTS: In the pathologic findings, the fraction of myocardial ECM (ECM%) was measured, with a significantly greater ECM% found in the AF group compared with the sham operated group (n = 6; i.e., pigs with normal sinus rhythm [SR]). A set of 9,182 genes was screened with cDNA microarray analysis. In AF animals, expression of 121 genes increased and 24 genes decreased by >= 1.75-fold compared with SR animals. Significant up-regulation of fibronectin-1 (4.9-fold), fibrillin-1 (3.1-fold), and fibromodulin (1.9-fold) in the fibrillating atria was confirmed by quantitative real-time reverse transcriptase-polymerase chain reaction. Western blot analysis revealed significantly increased atrial fibronectin-1, fibrillin-1, and fibromodulin in the AF group compared with the SR group (1.5-, 2.7-, and 2.1-fold, respectively). Immunohistochemical staining of AF tissue displayed increased accumulation of fibronectin-1 and fibrillin-1 in the atrial interstitial space. CONCLUSION: Increased expression of ECM proteins in fibrillating atria supports the hypothesis that ECM metabolism contributes to the development of AF.
Left Ventricular Extracellular Matrix Remodeling in Dogs with Right Ventricular Apical Pacing
(2010-10-01)
Lin, Jih-Min
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Lai, Ling-Ping
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Lin, Chih-Sheng
;
Chou, Nai-Kuan
;
Chiu, Chih-Yuan
Methods and Results: Dogs with pacemakers underwent AV nodal ablation. After 12 weeks of atria-sensed obligatory RV pacing, LVs were separated into septum and lateral wall for analysis. Zymographic activity, including matrix metalloproteinase-2 (MMP-2), MMP-9, tissue inhibitors of metalloproteinase-1 (TIMP-1), TIMP-3, collagen transcript expression, and histology were examined in opposite portions of the LV to identify possible ECM remodeling changes by RV apical pacing. Compared with sham-operated dogs, increased interstitial fibrosis and fragmentation of myofibrils was found in the LV lateral wall in the pacing group. Collagen type II mRNA showed a significant 2-fold increase in the LV lateral wall in the pacing group. Although collagen type I mRNA was increased, the difference was not significant. Zymography demonstrated MMP-9 activity was enhanced in both the LV lateral wall and septum in the pacing group, but MMP-2 activity was enhanced in the LV lateral wall. Immunfluorescence stain confirmed the activation of MMP-2 and MMP-9 in the LV lateral wall in the pacing group. Protein expression of TIMP-1 and TIMP-3 showed regional differences in the pacing group and both proteins were increased in the LV lateral wall. Conclusion: LV dyssynchrony by RV apical pacing elicits heterogeneous ECM remodeling in the LV. These findings assist in the elucidation of the pathophysiology of LV desynchronization. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1142-1149).
Left Ventricular Extracellular Matrix Remodeling in Dogs with Right Ventricular Apical Pacing
(2010-10-01)
Lin, Jih-Min
;
Lai, Ling-Ping
;
Lin, Chih-Sheng
;
Chou, Nai-Kuan
;
Chiu, Chih-Yuan
Methods and Results: Dogs with pacemakers underwent AV nodal ablation. After 12 weeks of atria-sensed obligatory RV pacing, LVs were separated into septum and lateral wall for analysis. Zymographic activity, including matrix metalloproteinase-2 (MMP-2), MMP-9, tissue inhibitors of metalloproteinase-1 (TIMP-1), TIMP-3, collagen transcript expression, and histology were examined in opposite portions of the LV to identify possible ECM remodeling changes by RV apical pacing. Compared with sham-operated dogs, increased interstitial fibrosis and fragmentation of myofibrils was found in the LV lateral wall in the pacing group. Collagen type II mRNA showed a significant 2-fold increase in the LV lateral wall in the pacing group. Although collagen type I mRNA was increased, the difference was not significant. Zymography demonstrated MMP-9 activity was enhanced in both the LV lateral wall and septum in the pacing group, but MMP-2 activity was enhanced in the LV lateral wall. Immunfluorescence stain confirmed the activation of MMP-2 and MMP-9 in the LV lateral wall in the pacing group. Protein expression of TIMP-1 and TIMP-3 showed regional differences in the pacing group and both proteins were increased in the LV lateral wall. Conclusion: LV dyssynchrony by RV apical pacing elicits heterogeneous ECM remodeling in the LV. These findings assist in the elucidation of the pathophysiology of LV desynchronization. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1142-1149).
Membrane translocation of small GTPase Rac1 and activation of STAT1 and STAT3 in pacing-induced sustained atrial fibrillation
(2008-09-01)
Tsai, Chia-Ti
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Lin, Jiunn-Lee
;
Lai, Ling-Ping
;
Lin, Chih-Sheng
;
Huang, Sheoi K. Stephen
BACKGROUND Angiotensin II and its downstream mitogen-activated protein kinase signaling pathways are involved in the pathogenesis of AF. Pro-inflammatory JAK/STAT is another downstream signaling pathway of Angiotensin II, and its status in AF remains unknown. OBJECTIVE The aim of this study was to characterize the status of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways in pacing-induced sustained atrial fibrillation (AF). METHODS AF was induced by atrial pacing at 600/min in 10 adult pigs (AF group), while 10 sham-operated pigs served as the control group. RESULTS Significant structural and inflammatory changes were noted in the AF group. Atrial tissue angiotensin II level was elevated and STAT1 and STAT3 were activated in the AF group. Nuclear translocation of activated STAT3 and binding to STAT3 consensus DNA sequence were also increased in the AF group. Rac1, the molecular target of statin, which mediates the activation of STAT3 by angiotensin II, was also activated in the AF group. The tissue levels of interteukin-6, leukemia inhibitory factor (LIF) and cardiotrophin-1 (CT-1), which are known to activate STATs through membrane gp130 and JAKs, were not increased in the AF group. Membrane gp130 and JAKs were also not activated in the AF group. CONCLUSION Activated angiotensin II/Rac1/STAT may be associated with or perhaps contribute to the structural and inflammatory changes in pacing-induced sustained trial fibrillation. It may further imply the therapeutic option of combination of angiotensin receptor blocker and statin.
Upregulation of matrix metalloproteinase-9 and tissue inhibitors of metalloproteinases in rapid atrial pacing-induced atrial fibrillation
(2008-12-01)
Chen, Chien-Lung
;
Huang, Shoei K. Stephen
;
Lin, Jiunn-Lee
;
Lai, Ling-Ping
;
Lai, Shao-Chuan
Remodeling of atrial extracellular matrix (ECM) in atrial fibrillation (AF) involves changes in the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs). The contributions of MMPs and TIMPs to the pathogenesis of AF development have not been clearly defined. This study evaluated the in situ activity and expression of gelatinases (MMP-2 and MMP-9) and their relationship with TIMP-1 or TIMP-3 in atria undergoing rapid atrial pacing for the induction of AF (4 weeks' pacing followed by 2 weeks of maintained AF) in pigs. In AF atria, in situ gelatinase activity was mainly localized in the interstitium of atrial myocardium, and was significantly larger than that of sinus rhythm control (i.e., sham control). The significant increase of MMP-9 in its pro-form and mRNA level, but not MMP-2, was shown to be responsible for the increased gelatinase activity in atria with AF. The inhibitory activities of glycosylated TIMP-1 and TIMP-3, but not TIMP-2, in AF tissues were markedly elevated and also localized in the atrial interstitium. TIMP-1 was found to be mostly colocalized with gelatinase activity over the AF tissues, implying the coexistence of gelatinase activity and TIMP-1, but TIMP-3 appeared only partially colocalized and discontinued the gelatinase activity surrounding the cardiomyocytes. TIMP-1 and TIMP-3 may play differential roles in the inhibition of gelatinase activity in vivo. Together with the survey of several MMPs transcripts and the level of transforming growth factor-beta 1 (TGF-beta 1), we proposed that the increased activity of gelatinase (i.e., MMP-9), TIMP-I and TIMP-3 and their interaction may contribute to atrial ECM remodeling of AF. (C) 2008 Elsevier Inc. All rights reserved.