scholarly journals How Abnormal Sympatho-Activation Can Potentially Develop Heart Failure: A Mini Review

Author(s):  
Ioannis Patrikios ◽  
Ioannis Patrikios ◽  
Mohammadali Badri

Cardiac sympathetic afferent that signal the sensation of cardiac pain, ostensibly, has more underlying mechanisms than what scientists have ever been led to believe. Cardiac sympathetic afferent reflex, also known as (CSAR), has been shown to be responsive to a variety of stimuli. Many of which scientists observed in increased levels during ischemia hydrogen ion, oxygen radicals, potassium, lactate, ATP, prostaglandins bradykinin, substance p and, finally and most importantly, endogenous substances (neurohormones) such as norepinephrine (NE). In the outset of chronic heart failure (HF), it has been known for a long time, that there are abnormalities in arterial baroreceptor input which depress its sensitivity, and arterial chemoreceptors seem augmented. Therefore, they tend to not only initiate sympathetic outflow but also to sensitise cardiac afferents which are appearing to do the same thing where there are abnormalities in vagus mechano-reflexes as well. Some of these receptors are in the spinal reticulate tract and interestingly these a third pathways give off neurons to the brainstem some in the hypothalamus and trance translate through the thalamus and then ultimately up into the cortex where we have sensation of pain. Here in this essay, we aim to discuss important aspects of cardiac failure in relation to abnormal sympatho-activators through evaluation of different available studies and animal models.

The prevalence of heart failure is markedly increased in individuals with diabetes mellitus. Numerous observational studies suggest that this increased risk for heart failure can be attributed to exacerbated vascular complications and the presence of increased risk factors in diabetic subjects. In addition, experimental studies revealed the presence of a number of distinct molecular alterations in the myocardium that occur independently of vascular disease and hypertension. Many of these molecular alterations are similarly observed in failing hearts of nondiabetic patients and have thus been proposed to contribute to the increased risk for heart failure in diabetes. The interest in understanding the underlying mechanisms of impaired cardio- vascular outcomes in diabetic individuals has much increased since the demonstration of cardioprotective effects of SGLT-2 inhibitors and GLP-1 receptor agonists in recent clinical trials. The current review therefore summarizes the distinct mechanisms that have been proposed to increase the risk for heart failure in diabetes mellitus.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
Y Hsiao ◽  
I Shimizu ◽  
T Wakasugi ◽  
S Jiao ◽  
T Watanabe ◽  
...  

Abstract Background/Introduction Mitochondria are dynamic regulators of cellular metabolism and homeostasis. The dysfunction of mitochondria has long been considered a major contributor to aging and age-related diseases. The prognosis of severe heart failure is still unacceptably poor and it is urgent to establish new therapies for this critical condition. Some patients with heart failure do not respond to established multidisciplinary treatment and they are classified as “non-responders”. The outcome is especially poor for non-responders, and underlying mechanisms are largely unknown. Purpose Studies indicate mitochondrial dysfunction has causal roles for metabolic remodeling in the failing heart, but underlying mechanisms remain to be explored. This study tried to elucidate the role of Mitofusin-1 in a failing heart. Methods We examined twenty-two heart failure patients who underwent endomyocardial biopsy of intraventricular septum. Patients were classified as non-responders when their left-ventricular (LV) ejection fraction did not show more than 10% improvement at remote phase after biopsy. Fourteen patients were classified as responders, and eight as non-responders. Electron microscopy, quantitative PCR, and immunofluorescence studies were performed to explore the biological processes or molecules involved in failure to respond. In addition to studies with cardiac tissue specific knockout mice, we also conducted functional in-vitro studies with neonatal rat ventricular myocytes. Results Twenty-two patients with IDCM who underwent endomyocardial biopsy were enrolled in this study, including 14 responders and 8 non-responders. Transmission electron microscopy (EM) showed a significant reduction in mitochondrial size in cardiomyocytes of non-responders compared to responders. Quantitative PCR revealed that transcript of mitochondrial fusion protein, Mitofusin-1, was significantly reduced in non-responders. Studies with neonatal rat ventricular myocytes (NRVMs) indicated that the beta-1 adrenergic receptor-mediated signaling pathway negatively regulates Mitofusin-1 expression. Suppression of Mitofusin-1 resulted in a significant reduction in mitochondrial respiration of NRVMs. We generated left ventricular pressure overload model with thoracic aortic constriction (TAC) in cardiac specific Mitofusin-1 knockout model (c-Mfn1 KO). Systolic function was reduced in c-Mfn1 KO mice, and EM study showed an increase in dysfunctional mitochondria in the KO group subjected to TAC. Conclusions Mitofusin-1 becomes a biomarker for non-responders with heart failure. In addition, our results suggest that therapies targeting mitochondrial dynamics and homeostasis would become next generation therapy for severe heart failure patients. Funding Acknowledgement Type of funding source: None


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin Luo ◽  
Jun Yin ◽  
Denise Dwyer ◽  
Tracy Yamawaki ◽  
Hong Zhou ◽  
...  

AbstractHeart failure with reduced ejection fraction (HFrEF) constitutes 50% of HF hospitalizations and is characterized by high rates of mortality. To explore the underlying mechanisms of HFrEF etiology and progression, we studied the molecular and cellular differences in four chambers of non-failing (NF, n = 10) and HFrEF (n = 12) human hearts. We identified 333 genes enriched within NF heart subregions and often associated with cardiovascular disease GWAS variants. Expression analysis of HFrEF tissues revealed extensive disease-associated transcriptional and signaling alterations in left atrium (LA) and left ventricle (LV). Common left heart HFrEF pathologies included mitochondrial dysfunction, cardiac hypertrophy and fibrosis. Oxidative stress and cardiac necrosis pathways were prominent within LV, whereas TGF-beta signaling was evident within LA. Cell type composition was estimated by deconvolution and revealed that HFrEF samples had smaller percentage of cardiomyocytes within the left heart, higher representation of fibroblasts within LA and perivascular cells within the left heart relative to NF samples. We identified essential modules associated with HFrEF pathology and linked transcriptome discoveries with human genetics findings. This study contributes to a growing body of knowledge describing chamber-specific transcriptomics and revealed genes and pathways that are associated with heart failure pathophysiology, which may aid in therapeutic target discovery.


2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Changwon Kho ◽  
Ahyoung Lee ◽  
Dongtak Jeong ◽  
Jae Gyun Oh ◽  
Antoine Chaanine ◽  
...  

Background: The cardiac calcium ATPase, SERCA2a, is a critical pump responsible for Ca2+ re-uptake during excitation-contraction coupling. Impaired Ca2+ uptake resulting from decreased expression and reduced activity of SERCA2a is a hallmark of heart failure. Accordingly, restoration of SERCA2a expression by gene transfer has proved to be effective in improving cardiac function in heart-failure patients, as well as in animal models. However, the underlying mechanisms of SERCA2a’s dysfunction remain incompletely understood. Methods and Results: In this study, we show that SERCA2a is modified by SUMO1 at lysine sites 480 and 585 and that this SUMOylation is essential for preserving SERCA2a ATPase activity and stability in mouse and human cells. SUMO1 and SERCA2a SUMOylation levels were both decreased in mouse and pig models of heart failure and failing human left ventricles. To determine whether reduced SUMO1 levels are responsible for reduced SERCA2a protein levels and reduced cardiac function, we used an adenovirus associated virus-mediated gene delivery approach to up-regulate SUMO1 in trans aortic constriction-induced mouse model of heart failure. We found that increasing SUMO1 levels led to a restoration of SERCA2a levels, improved hemodynamic performance, and reduced mouse mortality. By contrast, down-regulation of SUMO1 using small hairpin RNA accelerated cardiac functional deterioration and was accompanied by decreased SERCA2a function. Conclusion: In this study, we study a new mechanism for modulation of SERCA2a activity and beneficial effects of SUMO1 in the setting of heart failure. It suggests that changes in post-translational modifications of SERCA2a could negatively affect cardiac function in heart failure. Our data may provide a new platform for the design of therapeutic strategies for heart failure.


2021 ◽  
Author(s):  
Susanne Bauer ◽  
Christina Strack ◽  
Ekrem Ücer ◽  
Stefan Wallner ◽  
Ute Hubauer ◽  
...  

Aim: We assessed the 10-year prognostic role of 11 biomarkers with different pathophysiological backgrounds. Materials & methods/results: Blood samples from 144 patients with heart failure were analyzed. After 10 years of follow-up (median follow-up was 104 months), data regarding all-cause mortality were acquired. Regarding Kaplan–Meier analysis, all markers, except TIMP-1 and GDF-15, were significant predictors for all-cause mortality. We created a multimarker model with nt-proBNP, hsTnT and IGF-BP7 and found that patients in whom all three markers were elevated had a significantly worse long-time-prognosis than patients without elevated markers. Conclusion: In a 10-year follow-up, a combination of three biomarkers (NT-proBNP, hs-TnT, IGF-BP7) identified patients with a high risk of mortality.


2012 ◽  
Vol 7 (1) ◽  
pp. 35-38
Author(s):  
Mohammad Salman ◽  
Syed Allahsan ◽  
Manzoor Mahmood ◽  
Md Khairul Anam ◽  
Shahed Mohammad Anwar ◽  
...  

Acute heart failure is a major health problem responsible for several million hospitalizations worldwide each year. Standard therapy has not changed for long time and includes diuretics and variable use of vasodilators or inotropes. Recently Nesiritide and Levosimendan are two drugs for the treatment of acute heart failure which have been approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMEA), respectively. There was little concern that Nesiritide can worsen the renal failure but recent trials had abolished this concern. DOI: http://dx.doi.org/10.3329/uhj.v7i1.10208 UHJ 2011; 7(1): 35-38


2019 ◽  
Vol 316 (2) ◽  
pp. R110-R120 ◽  
Author(s):  
Yiming Shen ◽  
Jin Bong Park ◽  
So Yeong Lee ◽  
Seong Kyu Han ◽  
Pan Dong Ryu

Exercise training (ExT) normalizes elevated sympathetic nerve activity in heart failure (HF), but the underlying mechanisms are not well understood. In this study, we examined the effects of 3 wk of ExT on the electrical activity of the hypothalamic presympathetic neurons in the brain slice of HF rats. HF rats were prepared by ligating the left descending coronary artery. The electrophysiological properties of paraventricular nucleus neurons projecting to the rostral ventrolateral medulla (PVN-RVLM) were examined using the slice patch-clamp technique. The neuronal firing rate was elevated in HF rats, and ExT induced a reduction in the firing rate ( P < 0.01). This ExT-induced decrease in the firing rate was associated with an increased frequency of spontaneous and miniature inhibitory postsynaptic current (IPSCs; P < 0.05). There was no significant change in excitatory postsynaptic current. Replacing Ca2+ with Mg2+ in the recording solution reduced the elevated IPSC frequency in HF rats with ExT ( P < 0.01) but not in those without ExT, indicating an increase in the probability of GABA release. In contrast, ExT did not restore the reduced GABAA receptor-mediated tonic inhibitory current in HF rats. A GABAA receptor blocker (bicuculline, 20 μM) increased the firing rate in HF rats with ExT ( P < 0.01) but not in those without ExT. Collectively, these results show that ExT normalized the elevated firing activity by increasing synaptic GABA release in PVN-RVLM neurons in HF rats. Our findings provide a brain mechanism underlying the beneficial effects of ExT in HF, which may shed light on the pathophysiology of other diseases accompanied by sympathetic hyperactivation.


2008 ◽  
Vol 364 (1516) ◽  
pp. 511-517 ◽  
Author(s):  
Nina Stobbe ◽  
Marina Dimitrova ◽  
Sami Merilaita ◽  
H. Martin Schaefer

A large variety of predatory species rely on their visual abilities to locate their prey. However, the search for prey may be hampered by prey camouflage. The most prominent example of concealing coloration is background-matching prey coloration characterized by a strong visual resemblance of prey to the background. Even though this principle of camouflage was recognized to efficiently work in predator avoidance a long time ago, the underlying mechanisms are not very well known. In this study, we assessed whether blue tits ( Cyanistes caeruleus ) use chromatic cues in the search for prey. We used two prey types that were achromatically identical but differed in chromatic properties in the UV/blue range and presented them on two achromatically identical backgrounds. The backgrounds had either the same chromatic properties as the prey items (matching combination) or differed in their chromatic properties (mismatching combination). Our results show that birds use chromatic cues in the search for mismatching prey, whereupon chromatic contrast leads to a ‘pop-out’ of the prey item from the background. When prey was presented on a matching background, search times were significantly higher. Interestingly, search for more chromatic prey on the matching background was easier than search for less chromatic prey on the matching background. Our results indicate that birds use both achromatic and chromatic cues when searching for prey, and that the combination of both cues might be helpful in the search task.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Lili Wang ◽  
Qianhui Zhang ◽  
Kexin Yuan ◽  
Jing Yuan

The incidence rate of cardiovascular disease (CVD) has been increasing year by year and has become the main cause for the increase of mortality. Mitochondrial DNA (mtDNA) plays a crucial role in the pathogenesis of CVD, especially in heart failure and ischemic heart diseases. With the deepening of research, more and more evidence showed that mtDNA is related to the occurrence and development of CVD. Current studies mainly focus on how mtDNA copy number, an indirect biomarker of mitochondrial function, contributes to CVD and its underlying mechanisms including mtDNA autophagy, the effect of mtDNA on cardiac inflammation, and related metabolic functions. However, no relevant studies have been conducted yet. In this paper, we combed the current research status of the mechanism related to the influence of mtDNA on the occurrence, development, and prognosis of CVD, so as to find whether these mechanisms have something in common, or is there a correlation between each mechanism for the development of CVD?


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