Background: Acute stress-induced (takotsubo) cardiomyopathy can result in a heart failure phenotype with a prognosis comparable with that of myocardial infarction. In this study, we hypothesized that inflammation is central to the pathophysiology and natural history of takotsubo cardiomyopathy. Methods: In a multicenter study, we prospectively recruited 55 patients with takotsubo cardiomyopathy and 51 age-, sex-, and comorbidity-matched control subjects. During the index event and at the 5-month follow-up, patients with takotsubo cardiomyopathy underwent multiparametric cardiac magnetic resonance imaging, including ultrasmall superparamagnetic particles of iron oxide (USPIO) enhancement for detection of inflammatory macrophages in the myocardium. Blood monocyte subpopulations and serum cytokines were assessed as measures of systemic inflammation. Matched control subjects underwent investigation at a single time point. Results: Subjects were predominantly middle-aged (64±14 years) women (90%). Compared with control subjects, patients with takotsubo cardiomyopathy had greater USPIO enhancement (expressed as the difference between pre-USPIO and post-USPIO T2*) in both ballooning (14.3±0.6 milliseconds versus 10.5±0.9 milliseconds; P <0.001) and nonballooning (12.9±0.6 milliseconds versus 10.5±0.9 milliseconds; P =0.02) left ventricular myocardial segments. Serum interleukin-6 (23.1±4.5 pg/mL versus 6.5±5.8 pg/mL; P <0.001) and chemokine (C-X-C motif) ligand 1 (1903±168 pg/mL versus 1272±177 pg/mL; P =0.01) concentrations and classic CD14 ⁺⁺ CD16 ^- monocytes (90±0.5% versus 87±0.9%; P =0.01) were also increased whereas intermediate CD14 ⁺⁺ CD16 ⁺ (5.4±0.3% versus 6.9±0.6%; P =0.01) and nonclassic CD14 ⁺ CD16 ⁺⁺ (2.7±0.3% versus 4.2±0.5%; P =0.006) monocytes were reduced in patients with takotsubo cardiomyopathy. At 5 months, USPIO enhancement was no longer detectable in the left ventricular myocardium, although persistent elevations in serum interleukin-6 concentrations ( P =0.009) and reductions in intermediate CD14 ⁺⁺ CD16 ⁺ monocytes (5.6±0.4% versus 6.9±0.6%; P =0.01) remained. Conclusions: We demonstrate for the first time that takotsubo cardiomyopathy is characterized by a myocardial macrophage inflammatory infiltrate, changes in the distribution of monocyte subsets, and an increase in systemic proinflammatory cytokines. Many of these changes persisted for at least 5 months, suggesting a low-grade chronic inflammatory state. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02897739.

Background: Takotsubo cardiomyopathy is an increasingly recognized acute heart failure syndrome precipitated by intense emotional stress. Although there is an apparent rapid and spontaneous recovery of left ventricular ejection fraction, the long-term clinical and functional consequences of takotsubo cardiomyopathy are ill-defined. Methods: In an observational case-control study, we recruited 37 patients with prior (>12-month) takotsubo cardiomyopathy, and 37 age-, sex-, and comorbidity-matched control subjects. Patients completed the Minnesota Living with Heart Failure Questionnaire. All participants underwent detailed clinical phenotypic characterization, including serum biomarker analysis, cardiopulmonary exercise testing, echocardiography, and cardiac magnetic resonance including cardiac ³¹ P-spectroscopy. Results: Participants were predominantly middle-age (64±11 years) women (97%). Although takotsubo cardiomyopathy occurred 20 (range 13–39) months before the study, the majority (88%) of patients had persisting symptoms compatible with heart failure (median of 13 [range 0–76] in the Minnesota Living with Heart Failure Questionnaire) and cardiac limitation on exercise testing (reduced peak oxygen consumption, 24±1.3 versus 31±1.3 mL/kg/min, P <0.001; increased VE/V co ₂ slope, 31±1 versus 26±1, P =0.002). Despite normal left ventricular ejection fraction and serum biomarkers, patients with prior takotsubo cardiomyopathy had impaired cardiac deformation indices (reduced apical circumferential strain, −16±1.0 versus −23±1.5%, P <0.001; global longitudinal strain, −17±1 versus −20±1%, P =0.006), increased native T1 mapping values (1264±10 versus 1184±10 ms, P <0.001), and impaired cardiac energetic status (phosphocreatine/γ-adenosine triphosphate ratio, 1.3±0.1 versus 1.9±0.1, P <0.001). Conclusions: In contrast to previous perceptions, takotsubo cardiomyopathy has long-lasting clinical consequences, including demonstrable symptomatic and functional impairment associated with persistent subclinical cardiac dysfunction. Taken together our findings demonstrate that after takotsubo cardiomyopathy, patients develop a persistent, long-term heart failure phenotype. Clinical Trial Registration: URL: https://clinicaltrials.gov . Unique identifier: NCT02989454.

Macrophages become activated by their environment and develop polarized functions: classically activated (M1) macrophages eliminate pathogens but can cause tissue injury, whereas alternatively activated (M2) macrophages promote healing and repair. Mechanisms directing polarized activation, especially in vivo, are not understood completely, and here, we examined the role of SOCS proteins. M2 macrophages activated in vitro or elicited by implanting mice i.p. with the parasitic nematode Brugia malayi display a selective and IL-4-dependent up-regulation of SOCS1 but not SOCS3. Using siRNA-targeted knockdown in BMDM, we reveal that the enhanced SOCS1 is crucial for IL-4-induced M2 characteristics, including a high arginase I:iNOS activity ratio, suppression of T cell proliferation, attenuated responses to IFN-γ/LPS, and curtailed SOCS3 expression. Importantly, SOCS1 was essential in sustaining the enhanced PI3K activity that drives M2 activation, defining a new regulatory mechanism by which SOCS1 controls M2 polarization. By contrast, for M1 macrophages, SOCS1 was not only an important regulator of proinflammatory mediators (IL-6, IL-12, MHC class II, NO), but critically, for M1, we show that SOCS1 also restricted IL-10 secretion and arginase I activity, which otherwise would limit the efficiency of M1 macrophage proinflammatory responses. Together, our results uncover SOCS1, not only as a feedback inhibitor of inflammation but also as a critical molecular switch that tunes key signaling pathways to effectively program different sides of the macrophage balance.

Significance: Diabetic patients often suffer from impaired wound healing, which can develop into nonhealing diabetic ulcers, facilitate bacterial infections, and necessitate amputation. Current strategies for treatment have failed to achieve the anticipated efficacy and do not address the fundamental molecular abnormalities that prevent efficient wound closure. In this work, we introduce a previously unidentified approach to treating diabetic wound healing by using topically delivered spherical nucleic acids to effect the knockdown of ganglioside-monosialic acid 3 (GM3) synthase, a mediator of impaired wound healing, in type 2 diabetic mice. In addition to laying the groundwork for developing a therapy for a debilitating condition, this work also validates the critical role of GM3 in diabetic wound healing.

SOCS Proteins in Macrophage Polarization and Function

Summary: Macrophages respond to their microenvironment and develop polarized functions critical for orchestrating appropriate inflammatory responses. Classical (M1) activation eliminates pathogens while alternative (M2) activation promotes regulation and repair. M1 macrophage activation is strongly associated with suppressor of cytokine signalling 3 (SOCS3) expression in vitro, but the functional consequences of this are unclear and the role of SOCS3 in M1‐macrophage polarization in vivo remains controversial. To address these questions, we defined the characteristics and function of SOCS3‐expressing macrophages in vivo and identified potential mechanisms of SOCS3 action. Macrophages infiltrating inflamed glomeruli in a model of acute nephritis show significant up‐regulation of SOCS3 that co‐localizes with the M1‐activation marker, inducible nitric oxide synthase. Numbers of SOCS3^hi‐expressing, but not SOCS1^hi‐expressing, macrophages correlate strongly with the severity of renal injury, supporting their inflammatory role in vivo. Adoptive transfer of SOCS3‐short interfering RNA‐silenced macrophages into a peritonitis model demonstrated the importance of SOCS3 in driving production of pro‐inflammatory IL‐6 and nitric oxide, while curtailing expression of anti‐inflammatory IL‐10 and SOCS1. SOCS3‐induced pro‐inflammatory effects were due, at least in part, to its role in controlling activation and nuclear accumulation of nuclear factor‐κB and activity of phosphatidylinositol 3‐kinase. We show for the first time that SOCS3 also directs the functions of human monocyte‐derived macrophages, including efficient M1‐induced cytokine production (IL‐1β, IL‐6, IL‐23, IL‐12), attenuated signal transducer and activator of transcription 3 activity and ability of antigen‐loaded macrophages to drive T‐cell responses. Hence, M1‐associated SOCS3 was a positive regulator of pro‐inflammatory responses in our rodent models and up‐regulated SOCS3 is essential for effective M1‐macrophage activation and function in human macrophages.