What role does the stress response have in congestive heart failure?

Risk factors for short-term mortality in elderly hip fracture patients with complicated heart failure in the ICU: A MIMIC-IV database analysis using nomogram

BACKGROUND

Hip fracture is a prevalent and hazardous injury among the elderly population that often results in intensive care unit (ICU) admission due to various complications, despite advanced medical science. One common complication experienced in the ICU by elderly hip fracture patients is heart failure, which significantly impacts short-term survival rates. Currently, there is a deficit of adequate predictive models to forecast the short-term risk of death following heart failure for elderly hip fracture patients in the ICU. This study aims to identify independent risk factors for all-cause mortality within 30 days for elderly patients with hip fractures and heart failure while in the ICU in order to develop a predictive model.

METHOD

A total of 641 elderly patients with hip fractures combined with heart failure were recruited from the Medical Information Mart for Intensive Care IV dataset and randomized to the training and validation sets. The primary outcome was all-cause mortality within 30 days. The least absolute shrinkage and selection operator regression was used to reduce data dimensionality and select features. Multivariate logistic regression was used to build predictive models. Consistency index (C-index), receiver operating characteristic curve, and decision curve analysis (DCA) were used to measure the predictive performance of the nomogram.

RESULT

Our results showed that these variables including MCH, MCV, INR, monocyte percentage, neutrophils percentage, creatinine, and combined sepsis were independent factors for death within 30 days in elderly patients with hip fracture combined with heart failure in the ICU. The C-index was 0.869 (95% CI 0.823-0.916) and 0.824 (95% CI 0.749-0.900) for the training and validation sets, respectively. The results of the area under the curve and decision curve analysis (DCA) confirmed that the nomogram performed well in predicting elderly patients with hip fractures combined with heart failure in the ICU.

CONCLUSION

We developed a new nomogram model for predicting 30-day all-cause mortality in elderly patients with hip fractures combined with heart failure in the ICU, which could be a valid and useful clinical tool for clinicians for targeted treatment and prognosis prediction.

Screening and identification of effective components from modified Taohong Siwu decoction for protecting H9c2 cells from damage

We found that modified Taohong Siwu decoction (MTHSWD) had cardioprotective effects after myocardial ischemia-reperfusion injury. This study was to screen the effective components of MTHSWD that have protective effects on H9c2 cell injury through H₂O₂ injury model. Fifty-three active components were screened by CCK8 assay to detect cell viability. The anti-oxidative stress ability was evaluated by detecting the levels of total superoxide dismutase (SOD) and malondialdehyde (MDA) in cells. The anti-apoptotic effect was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL). Finally, the phosphorylation levels of ERK, AKT, and P38MAPK were detected by WB (Western blot) to study the protective mechanism of effective monomers against H9c2 cell injury. Among the 53 active ingredients of MTHSWD, ginsenoside Rb3, levistilide A, ursolic acid, tanshinone I, danshensu, dihydrotanshinone I, and astragaloside I could significantly increase the viability of H9c2 cells. The results of SOD and MDA showed that ginsenoside Rb3, tanshinone I, danshensu, dihydrotanshinone I, and tanshinone IIA could significantly reduce the content of lipid peroxide in cells. TUNEL results showed that ginsenoside Rb3, tanshinone I, danshensu, dihydrotanshinone I, and tanshinone IIA reduced apoptosis to varying degrees. The tanshinone IIA, ginsenoside Rb3, dihydrotanshinone I, and tanshinone I reduced the phosphorylation levels of P38MAPK and ERK in H9c2 cells induced by H₂O₂, and the phosphorylation level of ERK was also significantly reduced by danshensu. At the same time, tanshinone IIA, ginsenoside Rb3, dihydrotanshinone I, tanshinone I, and danshensu significantly increased AKT phosphorylation level in H9c2 cells. In conclusion, the effective ingredients in MTHSWD provide basic basis and experimental reference for the prevention and treatment of cardiovascular diseases.

Early-onset dietary restriction maintains mitochondrial health, autophagy and ER function in the left ventricle during aging

Dietary restriction (DR) exerts healthy benefits, including heart functions. However, the cardioprotective role of DR is till controversial among researchers due to the variation of DR conditions. The present study focuses on the protective effect of early-onset DR on cardiac injury using mitochondrial structure and expression of protein associated with mitochondrial homeostasis, autophagy and endoplasmic reticulum (ER) function as measures.

METHODS

Two-month-old mice were fed with a breeding diet ad libitum (AL) or DR (60% of AL) for 3 (Young) or 20 (Aged) months.

RESULTS

Body weight increased with aging, whereas DR treatment kept body weight consistent. DR mice exhibited a higher relative heart weight than AL mice. DR mice displayed lower plasma glucose levels, compared with AL groups. Furthermore, Aged-AL, but not Aged-DR mice, had increased collagen content and morphological distortions in the left ventricle (LV). Aged-DR mice had a higher ATP and lower TBARS in the LV than Aged-AL mice. Mitochondrial morphology was detected by electron microscopy; Aged-AL mice had increased abnormal morphology of mitochondria. Treatment with DR reduced abnormal mitochondrial accumulation. Aging elevated the protein expressions of mitochondrial functions and ER-induced apoptosis. Aging downregulated autophagy-related proteins and chaperones in the heart. Dietary restriction reversed those protein expressions.

CONCLUSIONS

The present study demonstrated a beneficial effect of early onset DR on cardiac aging. The age-dependent mitochondrial dysfunction and protein quality control dysregulation was significantly reversed by long-term DR, demonstrating a concordance with the beneficial effect in the heart.

MicroRNA‑138‑5p drives the progression of heart failure via inhibiting sirtuin 1 signaling

The present study aimed to investigate the regulatory effects of microRNA-138-5p (miR-138-5p) and sirtuin 1 (SIRT1) on the progression of heart failure (HF). The binding association between miR-138-5p and SIRT1 was assessed by the dual-luciferase reporter assay. By conducting reverse transcription-quantitative polymerase chain reaction and Western blotting, relative levels of SIRT1 and p53 regulated by miR-138-5p were detected. In vitro HF models were generated by hydrogen peroxide (H₂O₂) induction in AC-16 and human cardiomyocyte (HCM) cells, followed by detection of the regulatory effects of SIRT1 on cell apoptosis and p53 expression. MiR-138-5p was negatively correlated with the SIRT1 level in cardiomyocytes. By recognizing and specifically targeting SIRT1 3′-untranslated region (3′-UTR), miR-138-5p decreased the translational level of SIRT1 and inhibited its enzyme activity, thereby decreasing the deacetylation level of p53. Through downregulating SIRT1 and activating p53 signaling, miR-138-5p induced apoptosis in H₂O₂-induced AC-16 and HCM cells. By contrast, knockdown of miR-138-5p in the in vitro HF models significantly protected the cardiomyocytes. SIRT1 contributed toward alleviate HF by inhibiting cardiomyocyte apoptosis via enhancing the deacetylation level of p53. MiR-138-5p decreases the enzyme activity of SIRT1 by specifically targeting its 3′-UTR and activates p53 signaling, followed by triggering cardiomyocyte apoptosis during the process of HF. It is considered that miR-138-5p and SIRT1 may be potential diagnostic biomarkers and therapeutic targets for HF.

Endoplasmic reticulum stress-mediated mitochondrial dysfunction in aged hearts

Aging impairs the mitochondrial electron transport chain (ETC), especially in interfibrillar mitochondria (IFM). Mitochondria are in close contact with the endoplasmic reticulum (ER). Induction of ER stress leads to ETC injury in adult heart mitochondria. We asked if ER stress contributes to the mitochondrial dysfunction during aging. Subsarcolemmal mitochondria (SSM) and IFM were isolated from 3, 18, and 24 mo. C57Bl/6 mouse hearts. ER stress progressively increased with age, especially in 24 mo. mice that manifest mitochondrial dysfunction. OXPHOS was decreased in 24 mo. IFM oxidizing complex I and complex IV substrates. Proteomic analysis showed that the content of multiple complex I subunits was decreased in IFM from 24 mo. hearts, but remained unchanged in in 18 mo. IFM without a decrease in OXPHOS. Feeding 24 mo. old mice with 4-phenylbutyrate (4-PBA) for two weeks attenuated the ER stress and improved mitochondrial function. These results indicate that ER stress contributes to the mitochondrial dysfunction in aged hearts. Attenuation of ER stress is a potential approach to improve mitochondrial function in aged hearts.

Targeting mitochondrial fusion and fission proteins for cardioprotection

New treatments are needed to protect the myocardium against the detrimental effects of acute ischaemia/reperfusion (IR) injury following an acute myocardial infarction (AMI), in order to limit myocardial infarct (MI) size, preserve cardiac function and prevent the onset of heart failure (HF). Given the critical role of mitochondria in energy production for cardiac contractile function, prevention of mitochondrial dysfunction during acute myocardial IRI may provide novel cardioprotective strategies. In this regard, the mitochondrial fusion and fissions proteins, which regulate changes in mitochondrial morphology, are known to impact on mitochondrial quality control by modulating mitochondrial biogenesis, mitophagy and the mitochondrial unfolded protein response. In this article, we review how targeting these inter-related processes may provide novel treatment targets and new therapeutic strategies for reducing MI size, preventing the onset of HF following AMI.

PRMT1 suppresses ATF4-mediated endoplasmic reticulum response in cardiomyocytes

Endoplasmic reticulum (ER) stress signaling plays a critical role in the control of cell survival or death. Persistent ER stress activates proapoptotic pathway involving the ATF4/CHOP axis. Although accumulating evidences support its important contribution to cardiovascular diseases, but its mechanism is not well characterized. Here, we demonstrate a critical role for PRMT1 in the control of ER stress in cardiomyocytes. The inhibition of PRMT1 augments tunicamycin (TN)-triggered ER stress response in cardiomyocytes while PRMT1 overexpression attenuates it. Consistently, PRMT1 null hearts show exacerbated ER stress and cell death in response to TN treatment. Interestingly, ATF4 depletion attenuates the ER stress response induced by PRMT1 inhibition. The methylation-deficient mutant of ATF4 with the switch of arginine 239 to lysine exacerbates ER stress accompanied by enhanced levels of proapoptotic cleaved Caspase3 and phosphorylated-γH2AX in response to TN. The mechanistic study shows that PRMT1 modulates the protein stability of ATF4 through methylation. Taken together, our data suggest that ATF4 methylation on arginine 239 by PRMT1 is a novel regulatory mechanism for protection of cardiomyocytes from ER stress-induced cell death.

MicroRNA-183-3p up-regulated by vagus nerve stimulation mitigates chronic systolic heart failure via the reduction of BNIP3L-mediated autophagy

Chronic systolic heart failure (CSHF) was a complex syndrome. Recently, vagus nerve stimulation (VNS), a novel treatment method, has emerged for the treatment of CSHF. therefore the aim of this study was to explore the possible mechanism of VNS treatment alleviating CSHF in rats. Firstly, we found after VNS treatment for 72 h, the level of B-type natriuretic peptide in VNS group was lower than that in CSHF group. In addition, VNS treatment induced the elevated left ventricular ejection fraction level, reduced left ventricular end diastolic volume and left ventricular end systolic volume level in VNS group, suggesting a mitigation of CSHF by VNS. Then we found the level of miR-183-3p in CSHF group was much lower than that in VNS group by High-throughput sequencing. The further results indicated that Bcl-2 interacting protein 3 like (BNIP3L) was identified as the target gene of miR-183-3p, and the expression of BNIP3L was notably reduced in rats of VNS group compared with CSHF group. Moreover, the down-regulated expression of miR-183-3p increased BNIP3L-mediated autophagy in rats of CSHF group compared with VNS group. Further mechanism findings demonstrated that up-regulation of miR-183-3p reduced the expression of BNIP3L, while down-regulation of miR-183-3p facilitated the expression of BNIP3L in H9c2 cells. miR-183-3p could also regulate autophagy by targeting BNIP3L in vitro, which was manifested by overexpression of miR-183-3p to inhibit BNIP3L-mediated autophagy. Our data demonstrated that VNS treatment benefited CSHF via the up-regulation of miRNA-183-3p, which reduced the BNIP3L-mediated autophagy, providing a new therapeutic direction for CSHF.

MiR-147b inhibits cell viability and promotes apoptosis of rat H9c2 cardiomyocytes via down-regulating KLF13 expression

Recently, microRNAs (miRNAs) have been shown to involve in the process of heart failure. This study aims to investigate the functional role of miR-147b in rat H9c2 cardiomyocytes and explore the underlying molecular mechanisms. Cell viability of H9c2 cells was detected by MTT assay. Cell apoptosis was detected by flow cytometry. Expression of miR-147b and KLF13 mRNA was detected by quantitative real-time PCR. The relationship between miR-147b and KLF13 was verified by dual-luciferase reporter assay. Protein levels were detected by western blot analysis. It was found that H2O2 inhibited cell viability and promoted cell apoptosis of H9c2 cells in a concentration-dependent manner. MiR-147b overexpression suppressed cell viability and increased apoptosis in H9c2 cells, while knock-down of miR-147b increased cell viability and reduced apoptosis in H2O2-treated H9c2 cells. Luciferase reporter assay and in vitro functional assay showed that KLF13 was a downstream target of miR-147b, and KLF13 knock-down suppressed cell viability and induced apoptosis in H9c2 cells. Enforced expression of KLF13 restored the effects of miR-147b overexpression on cell viability and apoptosis in H9c2 cells. MiR-147b modulated the expression levels of apoptosis-related proteins, and the effects of miR-147b overexpression on apoptosis-related proteins levels were prevented by enforced expression of KLF13 in H9c2 cells. The in vivo experiments showed that miR-147b was up-regulated, and KLF13 was down-regulated in the myocardial tissues from rats with chronic heart failure. Collectively, miR-147b inhibits viability and promotes cell apoptosis by targeting KLF13 in H9c2 cells, which may be associated with the pathogenesis of heart failure.