Cardiac FGF23: a new player in myocardial infarction

Baseline fibroblast growth factor 23 is associated with long-term mortality in ST-elevation myocardial infarction-results from the augsburg myocardial infarction registry

Background

The aim of this study was to investigate the association between inflammatory plasma protein concentrations and long-term mortality in patients with ST-elevation myocardial infarction (STEMI).

Methods

For 343 STEMI patients recorded between 2009 and 2013 by the population-based Myocardial Infarction Registry Augsburg, 92 inflammatory plasma proteins were measured at the index event using the OLINK inflammation panel. In multivariable-adjusted Cox regression models, the association between each plasma protein and all-cause long-term mortality was investigated. Median follow-up time was 7.6 (IQR: 2.4) years. For plasma protein that showed a strong association with long-term mortality, a 5-year survival ROC analysis was performed.

Results

One plasma protein, namely Fibroblast Growth Factor 23 (FGF-23), was particularly well associated with long-term mortality in the multivariable-adjusted Cox model with an FDR-adjusted p-value of <0.001 and a Hazard Ratio (HR) of 1.57 [95% CI: 1.29-1.91]. In the 5-years ROC analysis, an AUC of 0.6903 [95% CI: 0.594-0.781] was estimated for FGF-23. All other plasma protein didńt show strong associations, each marker with FDR-adjusted p-values >0.05 in the multivariable-adjusted Cox models.

Conclusions

FGF-23 is independently associated with long-term mortality after STEMI and might play an important role in the response to myocardial injury. The results suggest FGF-23 to be a useful marker in the long-term treatment of STEMI patients and a potential target for drug development.

Bone marrow sinusoidal endothelium controls terminal erythroid differentiation and reticulocyte maturation

Within the bone marrow microenvironment, endothelial cells (EC) exert important functions. Arterial EC support hematopoiesis while H-type capillaries induce bone formation. Here, we show that BM sinusoidal EC (BM-SEC) actively control erythropoiesis. Mice with stabilized β-catenin in BM-SEC (Ctnnb1^OE-SEC) generated by using a BM-SEC-restricted Cre mouse line (Stab2-iCreF3) develop fatal anemia. While activation of Wnt-signaling in BM-SEC causes an increase in erythroblast subsets (PII-PIV), mature erythroid cells (PV) are reduced indicating impairment of terminal erythroid differentiation/reticulocyte maturation. Transplantation of Ctnnb1^OE-SEC hematopoietic stem cells into wildtype recipients confirms lethal anemia to be caused by cell-extrinsic, endothelial-mediated effects. Ctnnb1^OE-SEC BM-SEC reveal aberrant sinusoidal differentiation with altered EC gene expression and perisinusoidal ECM deposition and angiocrine dysregulation with de novo endothelial expression of FGF23 and DKK2, elevated in anemia and involved in vascular stabilization, respectively. Our study demonstrates that BM-SEC play an important role in the bone marrow microenvironment in health and disease.

Predicting outcome in acute myocardial infarction: an analysis investigating 175 circulating biomarkers

AIMS 

There is a paucity of studies comprehensively comparing the prognostic value of larger arrays of biomarkers indicative of different pathobiological axes in acute myocardial infarction (MI).

METHODS AND RESULTS 

In this explorative investigation, we simultaneously analysed 175 circulating biomarkers reflecting different inflammatory traits, coagulation activity, endothelial dysfunction, atherogenesis, myocardial dysfunction and damage, apoptosis, kidney function, glucose-, and lipid metabolism. Measurements were performed in samples from 1099 MI patients (SWEDEHEART registry) applying two newer multimarker panels [Proximity Extension Assay (Olink Bioscience), Multiple Reaction Monitoring mass spectrometry]. The prognostic value of biomarkers regarding all-cause mortality, recurrent MI, and heart failure hospitalizations (median follow-up ≤6.6 years) was studied using Lasso analysis, a penalized logistic regression model that considers all biomarkers simultaneously while minimizing the risk for spurious findings. Tumour necrosis factor-related apoptosis-inducing ligand receptor 2 (TRAIL-R2), ovarian cancer-related tumour marker CA 125 (CA-125), and fibroblast growth factor 23 (FGF-23) consistently predicted all-cause mortality in crude and age/sex-adjusted analyses. Growth-differentiation factor 15 (GDF-15) was strongly predictive in the crude model. TRAIL-R2 and B-type natriuretic peptide (BNP) consistently predicted heart failure hospitalizations. No biomarker predicted recurrent MI. The prognostic value of all biomarkers was abrogated following additional adjustment for clinical variables owing to our rigorous statistical approach.

CONCLUSION 

Apart from biomarkers with established prognostic value (i.e. BNP and to some extent GDF-15), several 'novel' biomarkers (i.e. TRAIL-R2, CA-125, FGF-23) emerged as risk predictors in patients with MI. Our data warrant further investigation regarding the utility of these biomarkers for clinical decision-making in acute MI.

Inhibition of macrophage migration inhibitory factor (MIF) as a therapeutic target in bleomycin-induced pulmonary fibrosis rats

Macrophage migration inhibitory factor (MIF) inhibition can attenuate pulmonary fibrosis, but the antifibrotic mechanism is unclear. Here we investigated the antifibrotic effect of MIF knockdown in rats with bleomycin (BLM)-induced pulmonary fibrosis. The results showed that MIF inhibition attenuated lung injury and extracellular matrix deposition; significantly reduced the levels of cytokines including transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), hydroxyproline (hyp), fibroblast growth factor 23 (FGF23), and secreted phosphoprotein 1 (Spp1); and inhibited the expression of CD68, F4/80, and α-smooth muscle actin (α-SMA) protein. MIF inhibition is associated with reduction of proinflammatory mediators and macrophage infiltration in lungs. In addition, MIF knockdown in the day 14 group was significantly better than MIF knockdown in day 1 group in terms of the above mentioned cytokines TGF-β1, IL-17, TNF-α. MIF knockdown in day 14 group showed a better trend than MIF knockdown in day 1 group in inhibition of hyp and α-SMA formation. Furthermore, MIF inhibition downregulated the FGF23, Spp1, anti-integrin alpha 10 (Itga10), laminin subunit alpha 1 (Lama1), thrombospondin 2 (THBS2), and Serpin family B member 5 (SERPINB5) mRNA levels and the p-Smad2/3 protein level. MIF knockdown may inhibit fibrosis through the TGF-β1/Smads signaling pathway. In addition, MIF inhibition protects against vascular remodeling via Thbs2 and Serpinb5 signaling. In summary, our study showed that knockdown of MIF can significantly inhibit lung inflammation and fibrosis in rats with BLM-induced pulmonary fibrosis. The future development of inhibitors targeting MIF may contribute to the treatment of pulmonary fibrosis.

The Protective Role of Klotho in CKD-Associated Cardiovascular Disease

Background

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality in advanced CKD. The major pathological changes of CKD-associated CVD are severe vascular media calcification, aberrant cardiac remodeling such as hypertrophy and fibrosis, as well as accelerated atherosclerosis. α-Klotho is proposed as an anti-aging gene, which is primarily expressed in the kidney. Recent studies reveal that α-Klotho deficiency is associated with profound cardiovascular dysfunction. Of note, CKD represents extremely declined α-Klotho levels, hinting that α-Klotho deficiency may be implicated in the pathogenesis of CKD-associated CVD.

Summary

Based on the pathogenic mechanism of α-Klotho deficiency and decreased Klotho levels in the circulation even early in stage 1 of CKD, α-Klotho serves as a sensitive biomarker for renal insufficiency and also a novel predictor of risk of overall mortality of CVD events in CKD. Meanwhile, loss of Klotho resulted from kidney dysfunction markedly contributes to the progressive development of CKD and CVD. By contrast, prevention of Klotho decline using exogenous supplementation or genetically activated ways by several mechanisms can dramatically mitigate cardiac dysfunction, prevent vascular calcification, and retard the progression of CKD-accelerated atherosclerosis.

Key Messages

Klotho deficiency is proposed as a novel predictive biomarker as well as a pathogenic contributor to CVD events in CKD. In the future, Klotho may be a crucial potential therapeutic strategy to decrease the burden of CVD comorbidity with CKD in clinics.