OPN is almost exclusively produced by galectin-3CD206 macrophages, which specifically appear in the infarct myocardium after MI. The IL-10-STAT3-galectin-3 axis is essential for OPN-producing reparative macrophage polarization after myocardial infarction, and these macrophages contribute to tissue repair by promoting fibrosis and clearance of apoptotic cells. These results suggest that galectin-3 may contribute to reparative fibrosis in the infarct myocardium by controlling OPN levels.

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Background Although 30‐day readmission is thought to be an important quality indicator in patients with hospitalized heart failure, its prognostic impact and comparison of patients who were readmitted beyond 30 days has not been investigated. We assessed early (0–30 days) versus midrange (31–90 days) readmission in terms of incidence and distribution, and elucidated whether the timing of readmission could have a different prognostic significance. Methods and Results We examined patients with hospitalized heart failure registered in the WET ‐ HF (West Tokyo Heart Failure) registry. The primary outcomes analyzed were all‐cause death and HF readmission. Data of 3592 consecutive patients with hospitalized heart failure (median follow‐up, 2.0 years [interquartile range, 0.8–3.1 years]; 39.6% women, mean age 73.9±13.3 years) were analyzed. Within 90 days after discharge, HF readmissions occurred in 11.1% patients. Of them, patients readmitted within 30 and 31 to 90 days after discharge accounted for 43.1% and 56.9%, respectively. Independent predictors of 30‐ and 90‐day readmission were almost identical, and after adjustment, readmission for HF within 90 days (including both early and midrange readmission) was an independent predictor of subsequent all‐cause death (hazard ratio, 2.36; P <0.001). Among 90‐day readmitted patients, the time interval from discharge to readmission was not significantly associated with subsequent all‐cause death. Conclusions Among patients readmitted within 90 days after index hospitalization discharge, ≈60% of readmission events occurred beyond 30 days. Patients readmitted within 90 days had a higher risk of long‐term mortality, regardless of the temporal proximity of readmission to the index hospitalization.

Doxorubicin (DOX) is the most widely used anthracycline anticancer agent; however, its cardiotoxicity limits its clinical efficacy. Numerous studies have elucidated the mechanisms underlying DOX-induced cardiotoxicity, wherein apoptosis has been reported as the most common final step leading to cardiomyocyte death. However, in the past two years, the involvement of ferroptosis, a novel programmed cell death, has been proposed. The purpose of this review is to summarize the historical background that led to each form of cell death, focusing on DOX-induced cardiotoxicity and the molecular mechanisms that trigger each form of cell death. Furthermore, based on this understanding, possible therapeutic strategies to prevent DOX cardiotoxicity are outlined. DNA damage, oxidative stress, intracellular signaling, transcription factors, epigenetic regulators, autophagy, and metabolic inflammation are important factors in the molecular mechanisms of DOX-induced cardiomyocyte apoptosis. Conversely, the accumulation of lipid peroxides, iron ion accumulation, and decreased expression of glutathione and glutathione peroxidase 4 are important in ferroptosis. In both cascades, the mitochondria are an important site of DOX cardiotoxicity. The last part of this review focuses on the significance of the disruption of mitochondrial homeostasis in DOX cardiotoxicity.

Background We previously reported that osteopontin plays an essential role in accelerating both reparative fibrosis and clearance of dead cells (efferocytosis) during tissue repair after myocardial infarction (MI) and galectin‐3 hi CD206 + macrophages is the main source of osteopontin in post‐MI heart. Interleukin‐10– STAT3 (signal transducer and activator of transcription 3)–galectin‐3 axis is essential for Spp1 (encoding osteopontin) transcriptional activation in cardiac macrophages after MI. Here, we investigated the more detailed mechanism responsible for functional maturation of osteopontin‐producing macrophages. Methods and Results In post‐MI hearts, Spp1 transcriptional activation occurred almost exclusively in MerTK (Mer tyrosine kinase) + galectin‐3 hi macrophages. The induction of MerTK on galectin‐3 hi macrophages is essential for their functional maturation including efferocytosis and Spp1 transcriptional activity. MerTK + galectin‐3 hi macrophages showed a strong activation of both STAT3 and ERK (extracellular signal‐regulated kinase). STAT3 inhibition suppressed the differentiation of osteopontin‐producing MerTK + galectin‐3 hi macrophages, however, STAT3 activation was insufficient at inducing Spp1 transcriptional activity. ERK inhibition suppressed Spp1 transcriptional activation without affecting MerTK or galectin‐3 expression. Concomitant activation of ERK is required for transcriptional activation of Spp1 . In Il‐10 knockout enhanced green fluorescent protein– Spp1 knock‐in mice subjected to MI, osteopontin‐producing macrophages decreased but did not disappear entirely. Interleukin‐10 and macrophage colony‐stimulating factor synergistically activated STAT3 and ERK and promoted the differentiation of osteopontin‐producing MerTK + galectin‐3 hi macrophages in bone marrow–derived macrophages. Coadministration of anti‐interleukin‐10 plus anti–macrophage colony‐stimulating factor antibodies substantially reduced the number of osteopontin‐producing macrophages by more than anti–interleukin‐10 antibody alone in post‐MI hearts. Conclusions Interleukin‐10 and macrophage colony‐stimulating factor act synergistically to activate STAT3 and ERK in cardiac macrophages, which in turn upregulate the expression of galectin‐3 and MerTK, leading to the functional maturation of osteopontin‐producing macrophages.

BACKGROUND: A variant of c.14429G>A (p.Arg4810Lys, rs112735431) in the ring finger protein 213 gene (RNF213; NM_001256071.2) has been recently identified as a risk allele for pulmonary arterial hypertension (PAH). PAH can be added as a new member of RNF213-associated vascular diseases, which include Moyamoya disease and peripheral pulmonary stenosis. Our aim was to identify the clinical features and outcomes of PAH patients with this variant. METHODS: Whole-exome sequencing was performed in 139 idiopathic (or possibly heritable) PAH patients. RESULTS: The RNF213 p.Arg4810Lys variant was identified in a heterozygous state in 11 patients (7.9%). Time-course changes in hemodynamics after combination therapy in the patients with the RNF213 p.Arg4810Lys variant were significantly poorer compared with those carrying the bone morphogenic protein receptor type 2 (BMPR2) mutation (n = 36) (comparison of changes in mean pulmonary arterial pressure, p = 0.007). The event-free rate of death or lung transplantation was significantly poorer in RNF213 p.Arg4810Lys variant carriers than in BMPR2 mutation carriers (5-year event-free rate since the introduction of prostaglandin I 2 infusion, 0% vs 93%, respectively; p < 0.001).

To extend life expectancy and ensure healthy aging, it is crucial to prevent and minimize age‐induced skeletal muscle atrophy, also known as sarcopenia. However, the disease's molecular mechanism remains unclear. The age‐related Wnt/β‐catenin signaling pathway has been recently shown to be activated by the (pro)renin receptor ((P)RR). We report here that (P)RR expression was increased in the atrophied skeletal muscles of aged mice and humans. Therefore, we developed a gain‐of‐function model of age‐related sarcopenia via transgenic expression of (P)RR under control of the CAG promoter. Consistent with our hypothesis, (P)RR‐Tg mice died early and exhibited muscle atrophy with histological features of sarcopenia. Moreover, Wnt/β‐catenin signaling was activated and the regenerative capacity of muscle progenitor cells after cardiotoxin injury was impaired due to cell fusion failure in (P)RR‐Tg mice. In vitro forced expression of (P)RR protein in C2C12 myoblast cells suppressed myotube formation by activating Wnt/β‐catenin signaling. Administration of Dickkopf‐related protein 1, an inhibitor of Wnt/β‐catenin signaling, and anti‐(P)RR neutralizing antibody, which inhibits binding of (P)RR to the Wnt receptor, significantly improved sarcopenia in (P)RR‐Tg mice. Furthermore, the use of anti‐(P)RR neutralizing antibodies significantly improved the regenerative ability of skeletal muscle in aged mice. Finally, we show that Yes‐associated protein (YAP) signaling, which is coordinately regulated by Wnt/β‐catenin, contributed to the development of (P)RR‐induced sarcopenia. The present study demonstrates the use of (P)RR‐Tg mice as a novel sarcopenia model, and shows that (P)RR‐Wnt‐YAP signaling plays a pivotal role in the pathogenesis of this disease.