Cardiac sympathetic activity is associated with inflammation and neurohumoral activation in patients with idiopathic dilated cardiomyopathy

Effectiveness of inspiratory muscle training associated with a cardiac rehabilitation program on sympathetic activity and functional capacity in patients with heart failure: a study protocol for a randomized controlled trial

BACKGROUND

Individuals affected by heart failure (HF) may present fatigue, dyspnea, respiratory muscle weakness, and sympathetic activity hyperstimulation of the myocardium, among other symptoms. Conducting cardiac rehabilitation (CR) programs can be associated with inspiratory muscle training. The aim of this study was to evaluate the efficacy of inspiratory muscular training (IMT) associated with a CR program on modulating myocardial sympathetic activity and maximal functional capacity, submaximal functional capacity, thickness, and mobility of the diaphragm muscle in patients with HF.

METHODS

We will conduct a clinical, controlled, randomized, double-blind trial that will include sedentary men and women who are 21-60 years old and who have diagnosed systolic HF and a left ventricular ejection fraction of less than 45%. Participants will be randomly assigned to one of two groups: experimental and control. The control group will follow the conventional CR protocol, and the experimental group will follow the conventional CR protocol associated with IMT 7 days a week. The two proposed exercise protocols will have a frequency of three times a week for a period of 12 weeks. The sympathetic innervation of the cardiac muscle, the maximum and submaximal functional capacity, diaphragm mobility and thickness, and the quality of life of the participants will be evaluated before and after the intervention protocol.

DISCUSSION

This clinical trial will be the first study to investigate the additional effects of IMT on CR in sympathetic hyperstimulation in the myocardium. The results of this study will contribute to developing therapeutic strategies collaborating to elucidate whether the association of IMT with CR can induce clinical benefits for patients with HF.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02600000. Registered November 9, 2015. Retrospectively registered.

A Comparison of Quantitative T2 Mapping on Cardiovascular Magnetic Resonance Imaging with Metaiodobenzylguanidine Scintigraphy and Left Ventricular Functional Recovery in Dilated Cardiomyopathy: A Retrospective Pilot Study

OBJECTIVE

Metaiodobenzylguanidine (MIBG) scintigraphy is used to assess heart failure (HF) severity and to predict cardiac functional recovery. Cardiovascular magnetic resonance (CMR) imaging has recently been used to diagnosis HF. We evaluated CMR T2 mapping and MIBG scintigraphy in dilated cardiomyopathy (DCM) patients.

METHODS

Consecutively, 22 DCM patients [aged 56.8 ± 13.4 years; 6 women and 16 men; left ventricular ejection fraction (LVEF), 31.9 ± 10.7%] who underwent T2 mapping and MIBG scintigraphy were retrospectively evaluated. Echocardiography results were recorded at baseline and the 6-month follow-up. Patients with an increased LVEF ≥15% between the 2 measures were considered to be responders. We measured each patient's T2 values and MIBG indices [the heart-to-mediastinum ratio (H/M) in the early phase, H/M in the delayed phase, and the washout rate (WOR)] at baseline. We compared these values between the 12 responders and 10 non-responders.

RESULTS

The mean T2 value for all patients was 64.5 ± 6.6 ms. The mean values of early H/M, delayed H/M, and WOR were 2.06 ± 0.25, 1.94 ± 0.35, and 43.5 ± 11.8%, respectively. The T2 values were found to correlate with MIBG indices (p<0.05 for all) and were lower in the responders than non-responders (61.4 vs. 68.1 ms, p=0.013). MIBG indices were not significantly different.

CONCLUSION

Our study shows that the T2 values correlated with the MIBG indices and were increased in non-responders. T2 mapping may be useful in assessing the cardiac function and functional recovery in DCM patients.

The cardiorenal syndrome in heart failure: cardiac? renal? syndrome?

There has been increasing interest on the so-called cardiorenal syndrome (CRS), defined as a complex pathophysiological disorder of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction in the other. In this review, we contend that there is lack of evidence warranting the adoption of a specific clinical construct such as the CRS within the heart failure (HF) syndrome by demonstrating that: (a) the approaches and tools regarding the definition of kidney involvement in HF are suboptimal; (b) development of renal failure in HF is often confounded by age, hypertension, and diabetes; (c) worsening of renal function (WRF) in HF may be largely independent of alterations in cardiac function; (d) the bidirectional association between HF and renal failure is not unique and represents one of the several such associations encountered in HF; and (e) inflammation is a common denominator for HF and associated noncardiac morbidities. Based on these arguments, we believe that dissecting one of the multiple bidirectional associations in HF and constructing the so-called cardiorenal syndrome is not justified pathophysiologically. Fully understanding of all morbid associations and not only the cardiorenal is of great significance for the clinician who is caring for the patient with HF.

The role of G protein coupled receptor kinases in neurocardiovascular pathophysiology

In coronary artery disease the G protein related kinases (GRKs) play a role in desensitization of β-adrenoreceptors (AR) after coronary occlusion. Targeted deletion and lowering of cardiac myocyte GRK-2 decreases the risk of post-ischemic heart failure (HF). Studies carried out in humans confirm the role of GRK-2 as a marker for the progression of HF after myocardial infarction (MI). The level of GRK-2 could be an indicator of β-AR blocker efficacy in patients with acute coronary syndrome. Elevated levels of GRK-2 are an early ubiquitous consequence of myocardial injury. In hypertension an increased level of GRK-2 was reported in both animal models and human studies. The role of GRKs in vagally mediated disorders such as vasovagal syncope and atrial fibrillation remains controversial. The role of GRKs in the pathogenesis of neurocardiological diseases provides an insight into the molecular pathogenesis process, opens potential therapeutic options and suggests new directins for scientific research.

Renal function in advanced heart failure

Despite recent advances with neurohormonal antagonists and devices, the prognosis of patients with advanced heart failure (HF) remains grave. Renal dysfunction is a common comorbid condition in HF and is associated with adverse outcomes. Current evidence indicates that intrinsic renal disease and inflammation in HF makes the kidney susceptible to hemodynamic compromise and congestion and contributes to a great extent to the development of renal dysfunction. Relief of congestion requires combination treatment with diuretics, neurohormonal antagonists, and occasionally vasodilators as well as inotropes. However, high doses of diuretics may accelerate the development of renal dysfunction by increasing neurohumoral activity and inducing renal structural and functional changes. Ultrafiltration should be reserved for patients with true diuretic resistance. Finally, early identification of the "patient at risk" remains a challenging issue and is limited by the currently used conventional parameters of renal function. However, novel biomarkers of acute kidney ischemia and/or injury are emerging and promise to become a diagnostic option for this patient population.

Characterization of Molecular Forms of N-Terminal B-Type Natriuretic Peptide In Vitro

BACKGROUND

The heterogeneity of circulating peptides may influence the interpretation of results from N-terminal profragment of BNP (NT-proBNP) assays. Our objective was to characterize the heterogeneity for better usability of the assays.

METHODS

Endogenous proBNP was purified from patient samples and treated with trifluoromethanesulfonic acid (chemical deglycosylation). The human proBNP gene was introduced into rat hearts by adenoviral transfer. Cell lysates and plasma samples containing proBNP-derived peptides were analyzed by chromatography. The fate of exogenous recombinant NT-proBNP added to fresh whole blood samples was followed by immunoassays and chromatography. The main NT-proBNP components were isolated and identified by mass spectrometry.

RESULTS

Immunoreactive NT-proBNP in human plasma comprised several molecular forms, as did circulating immunoreactive human NT-proBNP after adenoviral transfer of human proBNP cDNA into rat ventricular myocardium. Incubation of recombinant NT-proBNP1–76 in human plasma or serum resulted in multiple components with the 2 major components identified as NT-proBNP1–36 and NT-proBNP1–62/64. Profiling by different antisera and chromatography indicated masking of the non–mid-region epitopes likely due to formation of oligomers. More than 75% of the original immunoreactivity in the mid-region epitope was retained after 3-week storage of plasma samples at room temperature.

CONCLUSIONS

There is marked heterogeneity in immunoreactive NT-proBNP in plasma not related to glycosylation. The mid-region epitope of NT-proBNP is stable even in harsh storage conditions. Careful choice of antibody epitopes can yield extraordinarily robust assays.