Effect of Cardiac Resynchronization Therapy on Inflammation in Congestive Heart Failure: A Review

Left bundle branch pacing and cardiac remodeling in HF patients with type 2 diabetes mellitus: epigenetic pathways and clinical outcomes

Background

Left bundle branch (LBB) pacing could achieve cardiac resynchronization therapy (CRT) in patients who cannot be resynchronized via the placement of the left ventricle (LV) lead into the coronary sinus. LBB pacing could improve cardiovascular outcomes in heart failure (HF) patients with LBB block who are affected by type 2 diabetes mellitus (T2DM).

Study hypothesis

LBB pacing could increase the number of CRT responders and lead to the best clinical outcomes in HF patients with T2DM, inducing cardiac remodeling and improving left ventricle ejection fraction (LVEF) via microRNA (miR) modulation.

Methods

In a multicenter observational study, we enrolled 334 HF patients with LBB block and an indication to receive LBB pacing for CRT. In these patients, we evaluated the CRT responder rate, clinical outcomes, and miR expression at 1 year of follow-up.

Results

At 1 year of follow-up, we had 223 responders (66.8%), 132 hospitalizations for HF (39.5%), 24 cardiac deaths (7.2%), and 37 all-cause deaths (11.1%), with a higher rate of HF hospitalizations (77 (69.4%) vs 55 (24.7%), p < 0.05), and cardiac deaths (13 (11.7% vs 11 (4.9%), p < 0.05) in non-responders vs responders. At the end of follow-up, we found the lowest expression of miR-26, miR-29, miR-30, miR-92, and miR-145 in LBB-pacing non-responders vs responders (p < 0.05), and a direct correlation between miR-30 (0.340, [0.833-1.915]; p 0.001), the 6-minute-walking test (6MWT; 0.168, [0.008-0.060]; p 0.011), angiotensin-receptor-neprilysin inhibitors (ARNI; 0.157, [0.183-4.877]; p 0.035), sodium-glucose-transporter-2 inhibitors (0.245, [2.242-7.283]; p 0.001), and LVEF improvements. C reactive protein (CRP) inversely correlated with LVEF improvement (-0.220, [-(0.066-0.263)]; p 0.001). ARNI (1.373, CI 95% [1.007-1.872], p 0.045), miR-30 (2.713, CI 95% [1.543-4.769], p 0.001), and 6MWT (1.288, CI 95% [1.084-1.998], p 0.001) were predictors of LBB pacing responders at 1 year of follow-up.

Conclusion

LBB-pacing responders evidenced miR modulation, which was linked to significant improvement of the cardiac pump. Specifically, miR-30 was linked to cardiac pump improvement and predicted responders at 1 year of follow-up in patients with T2DM.

Interaction between cardiac resynchronization therapy and cytokines in heart failure patients

Congestive heart failure (CHF) is a complex multistage syndrome that has a great financial burden on human societies. It was known that the damaged myocardium sends a signal to stimulate the immune system and proliferation of leukocytes. In continuous, cytokine storm can be initiated and causes the probability of CHF. Persistent inflammation by increasing the levels of pro-inflammatory cytokines, plays an important role in the pathogenesis of CHF and causes remodeling, which is a progressive processs. Although treatment by drugs can reduce mortality and partially control the symptoms of heart failure patients, but complications and mortality are still high. Therefore, other treatment options such as Cardiac Resynchronization Therapy (CRT) are necessary. Today, it is known that CRT can be an effective treatment for many patients with heart failure. CRT is novel, non-pharmacological, and device-based therapy that would be beneficial to know more about its performance in the management of heart failure. In this study, we have reviewed the immunological processes involved in heart failure and the effect of CRT in controlling of the cytokine storm.

Reduced numbers of regulatory T cells in chronic heart failure seems not to be restored by cardiac resynchronization therapy

BACKGROUND

T cells have been implicated in the development and progression of inflammatory processes in chronic heart failure (CHF). Cardiac resynchronization therapy (CRT) has beneficial effects on symptoms and cardiac remodeling in CHF. However, its impact on the inflammatory immune response remains controversial. We aimed to study the impact of CRT on T cells in heart failure (HF) patients.

METHODS

Thirty-nine HF patients were evaluated before CRT (T0) and six months later (T6). Quantification of T cells, their subsets, and their functional characterization, after in vitro stimulation, were evaluated by flow cytometry.

RESULTS

T regulatory (Treg) cells were decreased in CHF patients (healthy group (HG): 1.08 ± 0.50 versus (heart failure patients (HFP)-T0: 0.69 ± 0.40, P = 0.022) and remaining diminished after CRT (HFP-T6: 0.61 ± 0.29, P = 0.003). Responders (R) to CRT presented a higher frequency of T cytotoxic (Tc) cells producing IL-2 at T0 compared with non-responders (NR) (R: 36.52 ± 12.55 versus NR: 24.71 ± 11.66, P = 0.006). After CRT, HF patients presented a higher percentage of Tc cells expressing TNF-α and IFN-γ (HG: 44.50 ± 16.62 versus R: 61.47 ± 20.54, P = 0.014; and HG: 40.62 ± 15.36 versus R: 52.39 ± 18.66, P = 0.049, respectively).

CONCLUSION

The dynamic of different functional T cell subpopulations is significantly altered in CHF, which results in an exacerbated pro-inflammatory response. Even after CRT, it seems that the inflammatory condition underlying CHF continues to evolve with the progression of the disease. This could be due, at least in part, to the inability to restore Treg cells levels.

TRIAL REGISTRATION

Observational and prospective study with no trial registration.

PACAP-38 and PAC1 Receptor Alterations in Plasma and Cardiac Tissue Samples of Heart Failure Patients

Pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) is a multifunctional neuropeptide, which may play a role in cardioprotection. However, little is known about the presence of PACAP-38 in heart failure (HF) patients. The aim of our study was to measure the alterations of PACAP-38 like immunoreactivity (LI) in acute (n = 13) and chronic HF (n = 33) and to examine potential correlations between PACAP-38 and HF predictors (cytokines, NT-proBNP). Tissue PACAP-38 LI and PAC1 receptor levels were also investigated in heart tissue samples of patients with HF. Significantly higher plasma PACAP-38 LI was detected in patients with acute HF, while in chronic HF patients, a lower level of immunoreactivity was observed compared to healthy controls (n = 13). Strong negative correlation was identified between plasma PACAP-38 and NT-proBNP levels in chronic HF, as opposed to the positive connection seen in the acute HF group. Plasma IL-1 β, IL-2 and IL-4 levels were significantly lower in chronic HF, and IL-10 was significantly higher in patients with acute HF. PACAP-38 levels of myocardial tissues were lower in all end-stage HF patients and lower PAC1 receptor levels were detected in the primary dilated cardiomyopathy group compared to the controls. We conclude that PACAP-38 and PAC1 expression correlates with some biomarkers of acute and chronic HF; therefore, further studies are necessary to explore whether PACAP could be a suitable prognostic biomarker in HF patients.

Cardiac resynchronization therapy reduces expression of inflammation-promoting genes related to interleukin-1β in heart failure

AIMS

In light of recent data regarding inflammatory signalling pathways in cardiovascular disease and the recently demonstrated impact of pharmacologic inhibition of interleukin-1β (IL-1β) in heart failure, the primary aim was to assess the physiologic effects of cardiac resynchronization therapy (CRT) on the expression of systemic inflammatory, immune-modulatory, metabolic, and apoptotic genes in peripheral blood mononuclear cells (PBMCs) of patients with heart failure.

METHODS AND RESULTS

We used RNA sequencing (RNA-Seq) and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) to identify gene expression changes in PBMCs in response to CRT. In total, 27 patients were analysed: 12 with heart failure undergoing CRT, 6 with heart failure undergoing standard implanted cardioverter defibrillators, and 9 with coronary artery disease but not heart failure. In CRT patients (median age 65.5 years, interquartile range 63.0-66.8 years, 33% female), RNA-Seq analysis identified 40 genes, including multiple genes associated with the IL-1β pathway, with significant correlations (false discovery rate < 0.05) with four key CRT response measures. CRT was associated with suppression of PBMC expression of IL-1β (1.80-fold decrease, P = 0.047), FOS proto-oncogene (FOS) (3.25-fold decrease, P = 0.01), dual specificity phosphatase 1 (DUSP1) (2.05-fold decrease, P = 0.001), and early growth response 1 (EGR1) (7.38-fold decrease, P = 0.03), and suppression was greater in responders vs. non-responders (P = 0.03 for IL-1β, P = 0.02 for FOS, P = 0.02 for DUSP1, and P = 0.11 for EGR1). Baseline FOS and DUSP-1 levels were greater in responders vs. non-responders (6.15-fold higher, FOS, P = 0.002; 2.60-fold higher, DUSP1, P = 0.0001). CRT responders but not non-responders showed higher baseline gene expression of FOS (P = 0.04) and DUSP1 (P = 0.06) compared with control patients without heart failure. Baseline serum high-sensitivity C-reactive protein levels were 3.47-fold higher in CRT responders vs. non-responders (P = 0.008).

CONCLUSION

Treatment of heart failure with CRT resulted in decreased PBMC expression of genes linked to inflammation. Moreover, CRT responders had higher expression of these inflammatory genes prior to CRT and greater suppression of these genes after CRT compared with non-responders.

Impact of cardiac resynchronization therapy on circulating IL-17 producing cells in patients with advanced heart failure

PURPOSE

IL-17-producing T cells have been implicated in the inflammatory milieu of chronic heart failure (CHF), which implies a dismal prognosis in affected patients. The aim of this study was to evaluate the impact of cardiac resynchronization therapy (CRT) on the frequency and functional activity of Th17 and Tc17 cells, as well as, on IL-17 mRNA expression in patients with CHF.

METHODS

Twenty-eight patients with CHF, analyzed before CRT (T0) and 6 months later (T6), and 15 healthy controls (HC) were enrolled in this study. Circulating Th17 and Tc17 cells were evaluated by flow cytometry. The quantification of IL-17A mRNA expression was performed by real-time PCR.

RESULTS

Circulating Tc17 cells tended to be higher in CHF patients submitted to CRT than in HC (0.92% (0.24-3.32) versus 0.60% (0.09-3.68), although not reaching statistical significance. The frequency of Tc17 cells in CHF patients significantly decreases after CRT reaching levels similar to those of HC (0.92% (0.24-3.32) at T0 versus 0.56% (0.21-4.20) at T6, P < 0.05), mainly due to responders to CRT. Additionally, the expression of IL-17 mRNA was detected in a few number of responder patients at T0 (27%) and only detected in one responder at T6 (7%). Conversely, in non-responders, the proportion of patients exhibiting IL-17 mRNA expression increases from baseline (17%) to T6 (42%). No significant differences were observed in Th17 cells between HC, CHF patients in T0 and patients in T6.

CONCLUSION

The inflammatory response mediated by circulating IL-17 producing cells seems to be suppressed by CRT, particularly in responders.

The Effect of Wenxin Keli on the mRNA Expression Profile of Rabbits with Myocardial Infarction

Aims. The molecular mechanisms of Chinese traditional medicine Wenxin Keli (WXKL) were unknown. This study was aimed at exploring the effects of WXKL on the gene expression profile and pathological alteration of rabbits with myocardial infarction. Methods. Twenty male adult rabbits were randomly divided into 4 groups: sham, model, WXKL, and captopril groups. Model, WXKL, and captopril groups underwent the ligation of the left anterior descending coronary artery while sham group went through an identical procedure without ligation. WXKL (817 mg/kg/d), captopril (8 mg/kg/d), and distilled water (to model and sham groups) were administered orally to each group. After 4 weeks, the rabbits were examined with echocardiography and the hearts were taken for expression chip and pathological staining (H&E, Masson, and Tunel) studies. Results. The data revealed that WXKL downregulated genes associated with inflammation (CX3CR1, MRC1, and FPR1), apoptosis (CTSC and TTC5), and neurohumoral system (ACE and EDN1) and upregulated angiogenesis promoting genes such as RSPO3. Moreover, the results also showed that WXKL improved cardiac function and prevented histopathological injury and apoptosis. Conclusion. The present study demonstrated that WXKL might play an important role in inhibiting inflammation, renin-angiotensin system, and apoptosis. It might be a promising Chinese medicine in the treatment of patients with myocardial infarction.