Chronic Heart Failure Abolishes Circadian Rhythms in Resting and Chemoreflex Breathing

Xinshubao tablet ameliorates myocardial injury against heart failure via the DCN/PPARα/PGC-1α/P300 pathway

Heart failure (HF) is a complex clinical syndrome with impaired ventricular ability due to structural or functional cardiac disorders. A traditional Chinese formula named Xinshubao tablet (XSB) is reported to protect cardiomyocytes and decrease the risk of HF clinically; however, the underlying mechanism of XSB on decreasing HF risk is not elucidated yet. Therefore, our study aimed to investigate the therapeutic efficacy and underlying mechanism of XSB by using HF model rats and H9c2 cells with oxygen glucose deprivation. Echocardiographic and pathological features of animal experiment showed that XSB treatment effectively improved cardiac function and ameliorated myocardial injury after 4 weeks of treatment. Cellular experiments indicated that XSB pretreatment significantly inhibited apoptosis and increased mitochondrial energy metabolism. Furthermore, in vivo and in vitro experiments both demonstrated that XSB suppressed oxidative stress and inflammatory response. Our results further revealed that the potential protective mechanism of XSB was closely associated with the DCN/PPARα/PGC-1α/P300 signaling pathway. Our findings provide novel mechanistic insights for HF treatment and a pharmacological basis for the therapeutic application of XSB against cardiovascular disorders.

Improving Diuretic Response in Heart Failure by Implementing a Patient-Tailored Variability and Chronotherapy-Guided Algorithm

Heart failure is a major public health problem, which is associated with significant mortality, morbidity, and healthcare expenditures. A substantial amount of the morbidity is attributed to volume overload, for which loop diuretics are a mandatory treatment. However, the variability in response to diuretics and development of diuretic resistance adversely affect the clinical outcomes. Morevoer, there exists a marked intra- and inter-patient variability in response to diuretics that affects the clinical course and related adverse outcomes. In the present article, we review the mechanisms underlying the development of diuretic resistance. The role of the autonomic nervous system and chronobiology in the pathogenesis of congestive heart failure and response to therapy are also discussed. Establishing a novel model for overcoming diuretic resistance is presented based on a patient-tailored variability and chronotherapy-guided machine learning algorithm that comprises clinical, laboratory, and sensor-derived inputs, including inputs from pulmonary artery measurements. Inter- and intra-patient signatures of variabilities, alterations of biological clock, and autonomic nervous system responses are embedded into the algorithm; thus, it may enable a tailored dose regimen in a continuous manner that accommodates the highly dynamic complex system.

Contribution of the Lung to the Genesis of Cheyne-Stokes Respiration in Heart Failure: Plant Gain Beyond Chemoreflex Gain and Circulation Time

Background

The contribution of the lung or the plant gain (PG; ie, change in blood gases per unit change in ventilation) to Cheyne‐Stokes respiration (CSR) in heart failure has only been hypothesized by mathematical models, but never been directly evaluated.

Methods and Results

Twenty patients with systolic heart failure (age, 72.4±6.4 years; left ventricular ejection fraction, 31.5±5.8%), 10 with relevant CSR (24‐hour apnea‐hypopnea index [AHI] ≥10 events/h) and 10 without (AHI <10 events/h) at 24‐hour cardiorespiratory monitoring underwent evaluation of chemoreflex gain (CG) to hypoxia (CGO2) and hypercapnia (CGCO2) by rebreathing technique, lung‐to‐finger circulation time, and PG assessment through a visual system. PG test was feasible and reproducible (intraclass correlation coefficient, 0.98; 95% CI, 0.91–0.99); the best‐fitting curve to express the PG was a hyperbola (R²≥0.98). Patients with CSR showed increased PG, CGCO2 (but not CGO2), and lung‐to‐finger circulation time, compared with patients without CSR (all P<0.05). PG was the only predictor of the daytime AHI (R=0.56, P=0.01) and together with the CGCO2 also predicted the nighttime AHI (R=0.81, P=0.0003) and the 24‐hour AHI (R=0.71, P=0.001). Lung‐to‐finger circulation time was the only predictor of CSR cycle length (R=0.82, P=0.00006).

Conclusions

PG is a powerful contributor of CSR and should be evaluated together with the CG and circulation time to individualize treatments aimed at stabilizing breathing in heart failure.