scholarly journals Sympathetic Nerve Innervation and Metabolism in Ischemic Myocardium in Response To Remote Ischemic Conditioning

2021 ◽  
Author(s):  
Attila Kiss ◽  
Xia Lu ◽  
Michaela Schlederer ◽  
Patrick M Pilz ◽  
Petra Lujza Szabo ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Sympathetic Nerve ◽  
Left Ventricular ◽  
Coronary Artery Ligation ◽  
Cardiac Sympathetic Nerve ◽  
Long Term Outcome ◽  
Remote Ischemic Conditioning ◽  
Ischemic Conditioning ◽  
Radionuclide Distribution ◽  
Significant Difference

Abstract Background Multiple potential interventions have been tested to protect the heart against myocardial ischemia/reperfusion (MIR) injury. Remote ischemic conditioning (RIC), an endogenous cardioprotective approach, could markedly improve cardiac function post-myocardial ischemia injury. In this study, we aimed to assess the effects of RIC on cardiac sympathetic nerve innervation and metabolism in the association with Chondroitin sulfate proteoglycans (GSPG). Methods Transient myocardial ischemia (30 min) is induced by ligature of the left anterior descending coronary artery ligation (LAD) in male Sprague Dawley rats (250-350 g), in vivo cardiac [11C]mHED and 2-[18F]FDG PET scans were performed at 14 days after ischemia. Remote ischemic preconditioning (RIPerc) was induced by three cycles of five-minute-long unilateral hind limb ischemia and intermittent five minutes of reperfusion during LAD occlusion period. The quantitative parameters were quantified in parametric polar maps. This standardized format facilitates the regional radioactive quantification of parameters in deficit regions to remote areas. The ex vivo radionuclide distribution was additionally identified using autoradiography. Myocardial neuron density and GSPG expression were assessed by immunohistochemistry. Results There was no significant difference in the metabolism-defected to the remote activity ratio (44.6±4.8% vs. 45.4±4.4%) between control rats (MIR) and treated (MIR+RIPerc) rats (P>0.05). Additionally, the mean nervous activity of denervated myocardium activity was significantly elevated in rats with RIPerc coupled with reduced denervated myocardium size compared to the rats MIR group (35.9±7.1% vs. 28.9±2.3% of the left ventricular (LV) remote area (P<0.05). These findings were associated with preserved LV systolic function and a significant reduction in GSPG expression in the myocardium. Conclusion RIPerc presented the effect on cardiac sympathetic nerve innervation following ischemia, but there is no significant effect on myocardial metabolism. A long-term outcome study is warranted.

scholarly journals N-11C-Methyl-Dopamine PET Imaging of Sympathetic Nerve Injury in a Swine Model of Acute Myocardial Ischemia: A Comparison with13N-Ammonia PET

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Weina Zhou ◽  
Xiangcheng Wang ◽  
Yulin He ◽  
Yongzhen Nie ◽  
Guojian Zhang ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Nerve Injury ◽  
Sympathetic Nerve ◽  
Blood Perfusion ◽  
Left Ventricular ◽  
Acute Myocardial Ischemia ◽  
Biological Information ◽  
Swine Model ◽  
Cardiac Sympathetic Nerve ◽  
Defect Volume

Objective. Using a swine model of acute myocardial ischemia, we sought to validateN-11C-methyl-dopamine (11C-MDA) as an agent capable of imaging cardiac sympathetic nerve injury.Methods. Acute myocardial ischemia was surgically generated in Chinese minipigs. ECG and serum enzyme levels were used to detect the presence of myocardial ischemia. Paired11C-MDA PET and13N-ammonia PET scans were performed at baseline, 1 day, and 1, 3, and 6 months after surgery to relate cardiac sympathetic nerve injury to blood perfusion.Results. Seven survived the surgical procedure. The ECG-ST segment was depressed, and levels of the serum enzymes increased. Cardiac uptake of tracer was quantified as the defect volume. Both before and immediately after surgery, the images obtained with11C-MDA and13N-ammonia were similar. At 1 to 6 months after surgery, however,11C-MDA postsurgical left ventricular myocardial defect volume was significantly greater compared to13N-ammonia.Conclusions. In the Chinese minipig model of acute myocardial ischemia, the extent of the myocardial defect as visualized by11C-MDA is much greater than would be suggested by blood perfusion images, and the recovery from myocardial sympathetic nerve injury is much slower than the restoration of blood perfusion.11C-MDA PET may provide additional biological information during recovery from ischemic heart disease.

Morphologic and functional analysis of myocardial status in pulmonary atresia with intact ventricular septum—an angiographic, histologic and morphometric study

1992 ◽  
Vol 2 (4) ◽  
pp. 361-366 ◽  
Author(s):  
Luciano Daliento ◽  
Roldano Scognamiglio ◽  
Gaetano Thiene ◽  
Anita Hegerty ◽  
Siew Yen Ho ◽  
...  
Keyword(s):  
Myocardial Ischemia ◽  
Pulmonary Atresia ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Ventricular Septum ◽  
Morphometric Study ◽  
Control Group ◽  
Intact Ventricular Septum ◽  
Significant Difference ◽  
Percentage Area

SummaryWe studied 11 patients with pulmonary atresia and intact ventricular septum who died at ages ranging from one day to three years. All but two neonates died after surgery. Pre-surgical catheterization with left and right cineventriculography was performed in nine patients, and quantitative parameters were calculated. By histologic examination of transverse transmural sections, the incidence and extent of myocardial ischemia or infarction were determined, as well as the percentage area per field occupied by vessels, myocytes orientated longitudinally or transversely, interstitial space, and disarrayed fibers. Comparable sections were obtained from six normal neonates to constitute a control group. Myocardial ischemia or infarction were frequent complications. Morphometric analysis demonstrated a significant difference between the control group and the patients with regard to the percentage of myocytes (longitudinal and transverse), the percentage of area occupied by myocardial disarray, and the presence of fibrosis. The highest values for the proportion of disarray were seen in those patients with small right ventricles. The percentage of myocytes varied, but the highest degree of disarray always correlated with the lowest percentage of myocytes. The highest percentage value of left ventricular disarray was associated with the lowest ratio of left ventricular mass to end diastolic volume (inadequate hypertrophy). The lowest indices of contractility and left ventricular pump function were associated with myocytes less than 55% of normal. A linear correlation was found between the percentage area of fibrosis and the ratio of systolic pressure to end systolic volume in the left ventricle, arid between fibrosis and ejection fraction. Values for fibrosis exceeding 15% were associated with decreased functional indices. Disarray, therefore, seems to express a primary inability of myocardium to respond to anomalous overload with adequate hypertrophy and/or hyperplasia.

Cardiac sympathetic afferent stimulation augments the arterial chemoreceptor reflex in anesthetized rats

2007 ◽  
Vol 102 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Lie Gao ◽  
Yan-Xia Pan ◽  
Wei-Zhong Wang ◽  
Yu-Long Li ◽  
Harold D. Schultz ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Sympathetic Nerve ◽  
Potassium Cyanide ◽  
Left Ventricular ◽  
Cardiac Sympathetic Nerve ◽  
Renal Sympathetic Nerve Activity ◽  
Pressor Responses ◽  
Cardiac Sympathetic Afferent Reflex ◽  
Arterial Chemoreceptor ◽  
Stimulation Of

Chronic heart failure (CHF) is well known to be associated with both an enhanced chemoreceptor reflex and an augmented cardiac “sympathetic afferent reflex” (CSAR). The augmentation of the CSAR may play an important role in the enhanced chemoreceptor reflex in the CHF state because the same central areas are involved in the sympathetic outputs of both reflexes. We determined whether chemical and electrical stimulation of the CSAR augments chemoreceptor reflex function in normal rats. Under anesthesia, renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded. The chemoreceptor reflex was tested by unilateral intra-carotid artery bolus injection of potassium cyanide (KCN) and nicotine. We found that 1) left ventricular epicardial application of capsaicin increased the pressor responses and the RSNA responses to chemoreflex activation induced by both KCN and nicotine; 2) when the central end of the left cardiac sympathetic nerve was electrically stimulated, both the pressor and the RSNA responses to chemoreflex activation induced by KCN were increased; 3) pretreatment with intracerebroventricular injection of losartan (500 nmol) completely prevented the enhanced chemoreceptor reflex induced by electrical stimulation of the cardiac sympathetic nerve; and 4) bilateral microinjection of losartan (250 pmol) into the nucleus tractus solitarii (NTS) completely abolished the enhanced chemoreceptor reflex by epicardial application of capsaicin. These results suggest that both the chemical and electrical stimulation of the CSAR augments chemoreceptor reflex and that central ANG II, specially located in the NTS, plays a major role in these reflex interactions.

scholarly journals Relationship between myocardial edema and left ventricular wall thickness in acute myocardial ischemia: A Magnetic Resonance Imaging study

2014 ◽  
Vol 1 (2) ◽  
pp. 23
Author(s):  
Yoko Mikami ◽  
Andreas Kumar ◽  
Hassan Abdel-Aty ◽  
Matthias G. Friedrich
Keyword(s):  
Magnetic Resonance ◽  
Myocardial Ischemia ◽  
Wall Thickness ◽  
Myocardial Injury ◽  
Myocardial Edema ◽  
Left Ventricular ◽  
Acute Myocardial Ischemia ◽  
Ischemia And Reperfusion ◽  
Significant Difference ◽  
T2 Weighted Images

Purpose: We sought to assess the relationship between left ventricular regional end-diastolic myocardial wall thickness (EDWT) and myocardial edema defined using T2-weighted Cardiovascular Magnetic Resonance (CMR) after acute myocardial ischemia and reperfusion. Methods: T2-weighted and cine CMR images for 7 dogs at baseline, during coronary occlusion (mean 33 ± 4 minutes) and after reperfusion were studied. The EDWT was measured in segments with high signal intensity (SI) on T2-weighted images, adjacent segments and remote segments according to a 16-segment model. Results: The EDWT after reperfusion in segments with high SI on T2-weighted images was significantly increased compared to baseline (6.28 ± 1.06 mm and 5.51 ± 1.40 mm, p < 0.05), whereas EDWT after the reperfusion in adjacent and remote segments did not show significant difference compared to baseline (adjacent: 6.48 ± 1.55 mm and 6.38 ± 1.26 mm, p = N.S., remote: 6.41 ± 1.11mm and 6.42 ± 1.27mm, p = N.S.). The % increase in EDWT after reperfusion from baseline in segments with high SI on T2-weighted images was higher than those in adjacent and remote segments (19 ± 30%, 1.3 ± 15% and 1.5 ± 16%, respectively, p < 0.05). Conclusions: After a brief period of ischemia and reperfusion, edema as defined by high SI on T2-weighted CMR is related to an increase in EDWT. This increase however is too small to be clinically relevant to be used for the detection of acute myocardial injury. Edema imaging is more sensitive and is an essential part of the reliable assessment of acute ischemic myocardial injury.

Abstract 19783: The Impact of Cardiac Sympathetic Nerve Activity Evaluated by Cardiac I-123 Metaiodobenzylguanidine Scintigraphy on the Chronotropic Incompetence

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Toshihiko Goto ◽  
Kazuaki Wakami ◽  
Kento Mori ◽  
Kenta Hachiya ◽  
Noriyuki Ikehara ◽  
...  
Keyword(s):  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Washout Rate ◽  
Mibg Scintigraphy ◽  
Cardiac Sympathetic Nerve ◽  
Chronotropic Incompetence ◽  
Nerve Activity ◽  
Cardiac Sympathetic Nerve Activity

Introduction: Chronotropic incompetence (CI), defined as the inability of the heart to increase its rate commensurate with increased activity, produces exercise intolerance, and is an independent predictor of overall mortality. Cardiac sympathetic nerve (SNS) activity has been suggested to have a relation to CI. However, the mechanisms for CI have not been fully elucidated. Thus, we investigated the cardiac SNS activity in patients with CI using cardiac I-123 metaiodobenzylguanidine (MIBG) scintigraphy. Methods: Sixteen patients with CI and 17 subjects who served as controls were enrolled in this study (age 77.5±9.2years; male 57.6%). Patients with CI were defined as who were implanted with pacemaker due to sick sinus syndrome. Results: There were no significant differences in age, sex, or left ventricular ejection fraction (66.3±14.3 vs 58.3±22.2%, ns) between patients with CI and controls. Plasma BNP level was also similar between two groups (79.0[IQR, 41.0-175.3] vs 90.9[IQR, 35.5-185.3]pg/mL, ns). The delayed heart/mediastinum (H/M) ratio was significantly higher in patients with CI than in controls (2.3±0.3 vs 2.0±0.4%, p=0.04). The early H/M ratio did not differ between two groups. The washout rate (WR) was significantly lower in patients with CI compared with that in controls (20.2±11.2 vs 33.3±14.1%, p=0.006). Conclusions: Decreased cardiac sympathetic nerve activity was associated with CI, and I-123 MIBG scintigraphy may be a useful modality for understanding the mechanism for CI.

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