Analysis of clinical features of heart failure in children with cardiomyopathy and improved ejection fraction

Background

The prognosis of children with heart failure varies considerably. After treatment, left ventricular ejection fraction (LVEF) can be improved in some children. The aim of this study was to analyze the clinical features of children with heart failure accompanied by cardiomyopathy and recovered ejection fraction [heart failure with recovered ejection fraction (HFrecEF)] and to identify the predictors of improved LVEF.

Methods

Children diagnosed with heart failure in Beijing Anzhen Hospital Affiliated to Capital Medical University from 2018 to 2021 were retrospectively enrolled. According to the baseline and change of LVEF, the patients were divided into two groups: a reduced ejection fraction (HFrEF) group and an HFrecEF group. The t-test was used to evaluate the difference between the two groups. The predictive factors of ejection fraction improvement were analyzed with a logistic regression model.

Results

A total of 72 children were included in this study, including 31 (43.1%) in the HFrEF group and 41 (56.9%) in the HFrecEF group. Compared with children in the HFrEF group, children in the HFrecEF group were younger and had faster resting heart rates, lower creatinine, lower suppression of tumorigenicity 2 (ST2) expression, a lower platelet-to-lymphocyte (PLT:LYM) ratio, and smaller left atrial diameter. After a mean follow-up of 35.87 months, 26 cases returned to normal ejection fraction. In the HFrEF group, sudden cardiac death occurred in two cases, and four cases received heart transplantation. Logistic analysis showed that virus infection [odds ratio (OR) =1.279; 95% confidence interval (CI): 0.374-4.379; P=0.007], low ST2 expression (cutoff value =1.89 ng/mL: OR =1.042; 95% CI: 1.007-1.082; P=0.032), and treatment with intravenous immunoglobulin (IVIG) (OR =5.077; 95% CI: 1.458-17.684; P=0.011) were predictors of improvement in LVEF in patients with heart failure after treatment.

Conclusions

In some patients with HFrecEF, LVEF eventually returned to normal. The combination of viral infection, low ST2 expression, and the application of IVIG therapy were found to be independent predictors of LVEF improvement in patients with heart failure after treatment.

Interleukin-33 Exacerbates IgA Glomerulonephritis in Transgenic Mice Overexpressing B Cell Activating Factor

BACKGROUND

The cytokine IL-33 is an activator of innate lymphoid cells 2 (ILC2s) in innate immunity and allergic inflammation. B cell activating factor (BAFF) plays a central role in B cell proliferation and differentiation, and high levels of this protein cause excess antibody production, including IgA. BAFF-transgenic mice overexpress BAFF and spontaneously develop glomerulonephritis that resembles human IgA nephropathy.

METHODS

We administered IL-33 or PBS to wild-type and BAFF-transgenic mice. After treating Rag1-deficient mice with IL-33, with or without anti-CD90.2 to preferentially deplete ILC2s, we isolated splenocytes, which were adoptively transferred into BAFF-transgenic mice.

RESULTS

BAFF-transgenic mice treated with IL-33 developed more severe kidney dysfunction and proteinuria, glomerular sclerosis, tubulointerstitial damage, and glomerular deposition of IgA and C3. Compared with wild-type mice, BAFF-transgenic mice exhibited increases of CD19⁺ B cells in spleen and kidney and ILC2s in kidney and intestine, which were further increased by administration of IL-33. Administering IL-33 to wild-type mice had no effect on kidney function or histology, nor did it alter the number of ILC2s in spleen, kidney, or intestine. To understand the role of ILC2s, splenocytes were transferred from IL-33-treated Rag1-deficient mice into BAFF-transgenic mice. Glomerulonephritis and IgA deposition were exacerbated by transfer of IL-33-stimulated Rag1-deficient splenocytes, but not by ILC2 (anti-CD90.2)-depleted splenocytes. Wild-type mice infused with IL-33-treated Rag1-deficient splenocytes showed no change in kidney function or ILC2 numbers or distribution.

CONCLUSIONS

IL-33-expanded ILC2s exacerbated IgA glomerulonephritis in a mouse model. These findings indicate that IL-33 and ILC2s warrant evaluation as possible mediators of human IgA nephropathy.

IL-33/ST2 Axis Plays a Protective Effect in Streptococcus pyogenes Infection through Strengthening of the Innate Immunity

Group A Streptococcus (GAS) causes invasive human diseases with the cytokine storm. Interleukin-33 (IL-33)/suppression of tumorigenicity 2 (ST2) axis is known to drive TH2 response, while its effect on GAS infection is unclear. We used an air pouch model to examine the effect of the IL-33/ST2 axis on GAS-induced necrotizing fasciitis. GAS infection induced IL-33 expression in wild-type (WT) C57BL/6 mice, whereas the IL-33- and ST2-knockout mice had higher mortality rates, more severe skin lesions and higher bacterial loads in the air pouches than those of WT mice after infection. Surveys of infiltrating cells in the air pouch of GAS-infected mice at the early stage found that the number and cell viability of infiltrating cells in both gene knockout mice were lower than those of WT mice. The predominant effector cells in GAS-infected air pouches were neutrophils. Absence of the IL-33/ST2 axis enhanced the expression of inflammatory cytokines, but not TH1 or TH2 cytokines, in the air pouch after infection. Using in vitro assays, we found that the IL-33/ST2 axis not only enhanced neutrophil migration but also strengthened the bactericidal activity of both sera and neutrophils. These results suggest that the IL-33/ST2 axis provided the protective effect on GAS infection through enhancing the innate immunity.

Estimating systemic fibrosis by combining galectin-3 and ST2 provides powerful risk stratification value for patients after acute decompensated heart failure

BACKGROUND

Two fibrosis biomarkers, galectin-3 (Gal-3) and suppression of tumorigenicity 2 (ST2), provide prognostic value additive to natriuretic peptides and traditional risk factors in patients with heart failure (HF). However, it is to be investigated whether their combined measurement before discharge provides incremental risk stratification for patients after acute HF.

METHODS

A total of 344 patients with acute HF were analyzed with Gal-3, and ST2 measured. Patients were prospectively followed for 3.7 ± 1.3 years for deaths, and composite events (death/HF-related re-hospitalizations).

RESULTS

The levels of Gal-3 and ST2 were only slightly related (r = 0.20, p < 0.001). The medians of Gal-3 and ST2 were 18 ng/mL and 32.4 ng/mL, respectively. These biomarkers compensated each other and characterized patients with different risk factors. According to the cutoff at median values, patients were separated into four subgroups based on high and low Gal-3 (HG and LG, respectively) and ST2 levels (HS and LS, respectively). Kaplan-Meier survival curves showed that HGHS powerfully identified patients at risk of mortality (Log rank = 21.27, p < 0.001). In multivariable analysis, combined log(Gal-3) and log(ST2) was an in-dependent predictor. For composite events, Kaplan-Meier survival curves showed a lower event- -free survival rate in the HGHS subgroup compared to others (Log rank = 34.62, p < 0.001; HGHS vs. HGLS, Log rank = 4.00, p = 0.045). In multivariable analysis, combined log(Gal-3) and log(ST2) was also an independent predictor.

CONCLUSIONS

Combination of biomarkers involving heterogeneous fibrosis pathways may identify patients with high systemic fibrosis, providing powerful risk stratification value.