Prolargin and matrix metalloproteinase-2 in heart failure after heart transplantation and their association with haemodynamics

CXCR7 promotes pulmonary vascular remodeling via targeting p38/MMP2 pathway in pulmonary arterial hypertension

Background

A hallmark feature of pulmonary arterial hypertension (PAH) is the excessive proliferation of pulmonary artery smooth muscle cells (PASMCs) in the pulmonary arteries. The exact role of C-X-C motif chemokine ligand 12 (CXCL12)/chemokine receptor type 7 (CXCR7) in the PASMCs remains unknown. This study was conducted to investigate CXCR7's role in p38/MMP2 pathway and its effect on PASMCs.

Methods

In this study, we examined the expression profile of CXCL12/CXCR7 in both hypoxic rats and PASMCs. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to measure the level of proliferation in PASMCs. Enzyme-linked immunosorbent assay (ELISA) and western blotting assays were applied to investigate the protein expression of the related molecules.

Results

We found that a high level of CXCR7 was correlated with remodeled pulmonary arterioles in hypoxic rats. Moreover, CXCR7 protein levels were significantly increased by the induction of CXCL12, indicating that the CXCL12-CXCR7 axis participates in PAH. During hypoxia-PAH, CXCR7 inhibition reduces right ventricular systolic pressure (RVSP), the Fulton index, and pulmonary arteriosclerosis remodeling. Further study indicated inhibition CXCR7 reduced PASMCs by downregulating MMP2, via p38 MAPK pathway. It was additionally found that CXCL12/CXCR7 stimulated the phosphorylation of the p38 MAPK pathway, which was a contributing factor to the decrease in MMP2 expression following preconditioning with SB203580, which inhibited p38 MAPK.

Conclusions

In summary, these findings suggest that CXCL12/CXCR7 plays a critical role in PAH, the therapy of which can be developed further by targeting its potential targets.

Innovative therapeutic strategies for cardiovascular disease

As a significant non-communicable disease, cardiovascular disease is the leading cause of death for both men and women, comprises almost twenty percent of deaths in most racial and ethnic groups, can affect greater than twenty-five million individuals worldwide over the age of twenty, and impacts global economies with far-reaching financial challenges. Multiple factors can affect the onset of cardiovascular disease that include high serum cholesterol levels, elevated blood pressure, tobacco consumption and secondhand smoke exposure, poor nutrition, physical inactivity, obesity, and concurrent diabetes mellitus. Yet, addressing any of these factors cannot completely eliminate the onset or progression of cardiovascular disorders. Novel strategies are necessary to target underlying cardiovascular disease mechanisms. The silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), a histone deacetylase, can limit cardiovascular injury, assist with stem cell development, oversee metabolic homeostasis through nicotinamide adenine dinucleotide (NAD+) pathways, foster trophic factor protection, and control cell senescence through the modulation of telomere function. Intimately tied to SIRT1 pathways are mammalian forkhead transcription factors (FoxOs) which can modulate cardiac disease to reduce oxidative stress, repair microcirculation disturbances, and reduce atherogenesis through pathways of autophagy, apoptosis, and ferroptosis. AMP activated protein kinase (AMPK) also is critical among these pathways for the oversight of cardiac cellular metabolism, insulin sensitivity, mitochondrial function, inflammation, and the susceptibility to viral infections such as severe acute respiratory syndrome coronavirus that can impact cardiovascular disease. Yet, the relationship among these pathways is both intricate and complex and requires detailed insight to successfully translate these pathways into clinical care for cardiovascular disorders.

Single-cell genomics illustrates heterogeneous phenotypes of myocardial fibroblasts under ischemic insults

Myocardial regenerative strategies are promising where the choice of ideal cell population is crucial for successful translational applications. Herein, we explored the regenerative/repair responses of infarct zone cardiac fibroblast(s) (CF) by unveiling their phenotype heterogeneity at single-cell resolution. CF were isolated from the infarct zone of Yucatan miniswine that suffered myocardial infarction, cultured under simulated ischemic and reperfusion, and grouped into control, ischemia, and ischemia/reperfusion. The single-cell RNA sequencing analysis revealed 19 unique cell clusters suggesting distinct subpopulations. The status of gene expression (log2 fold change (log2 FC) > 2 and log2 FC < -2) was used to define the characteristics of each cluster unveiling with diverse features, including the pro-survival/cardioprotective (Clusters 1, 3, 5, 9, and 18), vasculoprotective (Clusters 2 and 5), anti-inflammatory (Clusters 4 and 17), proliferative (Clusters 4 and 5), nonproliferative (Clusters 6, 8, 11, 16, 17, and 18), proinflammatory (Cluster 6), profibrotic/pathologic (Clusters 8 and 19), antihypertrophic (Clusters 8 and 10), extracellular matrix restorative (Clusters 9 and 12), angiogenic (Cluster 16), and normal (Clusters 7 and 15) phenotypes. Further understanding of these unique phenotypes of CF will provide significant translational opportunities for myocardial regeneration and cardiac management.

Elevated plasma WIF-1 levels are associated with worse prognosis in heart failure with pulmonary hypertension

AIMS

Heart failure (HF) is a progressive condition that is becoming more prevalent in the ageing population. Pulmonary hypertension is a common complicating factor in HF and negatively impacts survival. Plasma biomarkers are a potential method for determining the prognosis of patients with left heart failure with pulmonary hypertension (LHF-PH). We aimed to analyse the prognostic capability of 33 proteins related to, among other pathways, inflammation, coagulation, and Wnt signalling in LHF-PH.

METHODS

Plasma levels of 33 proteins were analysed using proximity extension assay from the plasma of 20 controls and 67 LHF-PH patients, whereof 19 underwent heart transplantation (HT). Haemodynamics in the patients were assessed using right heart catheterization.

RESULTS

Eleven proteins had elevated plasma levels in LHF-PH compared with controls (P < 0.01), which decreased towards the controls' levels after HT (P < 0.01). Survival analysis of these proteins showed that elevated plasma levels of growth hormone, programmed cell death 1 ligand 2, tissue factor pathway inhibitor 2, and Wnt inhibitory factor 1 (WIF-1) were associated with worse transplantation-free survival in LHF-PH (P < 0.05). When adjusted for age, sex and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels using multivariable cox regressions, only WIF-1 remained prognostic [hazard ratio (95% confidence interval)] [1.013 (1.001-1.024)]. WIF-1 levels in LHF-PH patients also correlated with the mean right atrial pressure (r_s  = 0.42; P < 0.01), stroke volume index (r_s  = 0.41; P < 0.01), cardiac index (r_s  = -0.42; P < 0.01), left ventricular stroke work index (r_s  = -0.41; P < 0.01), and NT-proBNP (r_s  = 0.63; P < 0.01).

CONCLUSIONS

The present study demonstrated that LHF-PH patients have higher plasma WIF-1 levels than healthy controls, suggesting that plasma WIF-1 may be a potential future prognostic biomarker in LHF-PH. Its prognostic capability could be further refined by including it in a multi-marker panel. Further studies are needed to establish the potential role of WIF-1 in LHF-PH pathophysiology in larger cohorts to determine its clinical applicability.

Plasma proteoglycan prolargin in diagnosis and differentiation of pulmonary arterial hypertension

Aims

Right ventricular dysfunction may arise because of pulmonary arterial hypertension (PAH). Development of new diagnostic methods able to identify PAH and allow for earlier treatment initiation, before the development of vascular remodelling and manifest right heart failure (HF), could potentially improve prognosis. Proteoglycans and inflammatory proteins are involved in vascular remodelling. We aimed to investigate their potential as biomarkers to differentiate PAH in a dyspnoeic population.

Methods and results

Plasma from 152 patients with PAH (n = 48), chronic thrombo‐embolic pulmonary hypertension (n = 20), pulmonary hypertension due to HF with reduced (n = 36) or preserved (n = 33) ejection fraction, and HF without pulmonary hypertension (n = 15) and 20 healthy controls were analysed with proximity extension assays. Haemodynamics were assessed in the patients with right heart catheterization. Plasma prolargin levels in PAH were lower compared with all the other studied disease groups (P < 0.001) but higher than the controls' levels (P = 0.003). Receiver operating characteristic curve of prolargin as a PAH‐differentiating marker in a pooled population, encompassing all the other studied disease groups, had a sensitivity of 74% and a specificity of 83.3% (area under the curve = 0.84, P < 0.001). Prolargin correlated with the mean right atrial pressure (r_s = 0.65, P < 0.001), N‐terminal pro‐brain natriuretic peptide (r_s = 0.64, P < 0.001), cardiac index (r_s = −0.31, P = 0.029), stroke volume index (r_s = −0.41, P = 0.004), right ventricular stroke work index (r_s = −0.31, P = 0.032), six‐minute walking distance (r_s = −0.41, P = 0.005), and mixed venous blood oxygen saturation (r_s = −0.42, P = 0.003).

Conclusions

Plasma prolargin levels differentiate PAH patients from controls and the other investigated dyspnoea groups including HF. Its potential in PAH differentiation may be enhanced by inclusion in a multi‐marker panel. Larger studies are needed to evaluate its discriminative ability of PAH in relation to other dyspnoea aetiologies and its potential role in PAH risk stratification and pathobiology.

Elevated plasma endocan and BOC in heart failure patients decrease after heart transplantation in association with improved hemodynamics

BACKGROUND

The prevalence of heart failure (HF) is rising with ageing population and constitutes a major health problem globally. A common complication of HF is pulmonary hypertension (PH) which negatively impacts survival. A pathophysiological association between HF and PH with tumorigenic processes has been suggested. We aimed to identify the plasma levels of, and the association between tumour-related proteins and hemodynamic improvements in patients with HF and PH due to left heart disease (LHD) before and 1-year after heart transplantation (HT).

METHODS

Forty-eight tumour-related proteins were measured with proximity extension assay in plasma from 20 controls and 26 HF patients before and 1-year after HT. Patients' hemodynamics were measured with right heart catheterization.

RESULTS

Out of 48 proteins, specifically, plasma levels of endocan and brother of CDO (BOC) were elevated in end-stage HF patients compared to controls (p < 0.001), but decreased after HT (p < 0.01), towards controls' levels. The decrease of endocan levels after HT correlated with improved mean pulmonary arterial pressure (rs = 0.80, p < 0.0001), pulmonary arterial wedge pressure (rs = 0.63, p = 0.0012), and pulmonary vascular resistance (rs = 0.70, p < 0.001). The decrease and normalization of BOC after HT correlated with decreased mean right atrial pressure (rs = 0.61 p = 0.0015) and NT-proBNP (rs = 0.57, p = 0.0022), as well as increased cardiac index (rs = - 0.51, p = 0.0086) and left-ventricular stroke work index (rs = - 0.57, p = 0.0039).

CONCLUSION

Our results suggest that (i) plasma endocan in HF may reflect the state of pulmonary vascular congestion and PH-LHD, whereas (ii) plasma BOC may reflect the cardiac function and the hemodynamic overload in HF. The exact role of these proteins and their clinical applicability as biomarkers in HF and PH-LHD ought to be investigated in larger cohorts.

Elevated plasma sRAGE and IGFBP7 in heart failure decrease after heart transplantation in association with haemodynamics

Aims

Metabolic derangement is implicated in the pathophysiology of heart failure (HF) and pulmonary hypertension (PH). We aimed to identify the dynamics of metabolic plasma proteins linked to end‐stage HF and associated PH in relation to haemodynamics, before and after heart transplantation (HT).

Methods and results

Twenty‐one metabolic plasma proteins were analysed with proximity extension assay in 20 controls and 26 patients before and 1 year after HT. Right heart catheterizations were performed in the HF patients pre‐operatively and 1 year after HT. Plasma levels of soluble receptor for advanced glycation end products (sRAGE) and insulin‐like growth factor‐binding protein 7 (IGFBP7) were higher in HF patients compared with controls (P < 0.0001) and decreased after HT (P < 0.0001), matching controls' levels. The decrease in sRAGE after HT correlated with improved mean pulmonary arterial pressure (r_s = 0.7; P < 0.0001), pulmonary arterial wedge pressure (r_s = 0.73; P < 0.0001), pulmonary vascular resistance (r_s = 0.65; P = 0.00062), and pulmonary arterial compliance (r_s = −0.52; P = 0.0074). The change in plasma IGFBP7 after HT correlated with improved mean right atrial pressure (r_s = 0.71; P = 0.00011) and N‐terminal pro‐brain natriuretic peptide (r_s = 0.71; P < 0.0001).

Conclusions

Our results indicate that plasma sRAGE may reflect passive pulmonary vascular congestion and the ‘mechanical’ state of the pulmonary vasculature in HF patients with or without related PH. Furthermore, sRAGE and IGFBP7 may provide additional insight into the pathophysiological mechanisms in HF and associated PH. Their potential clinical and therapeutic relevance in HF and associated PH need further investigation.

Elevated plasma tyrosine kinases VEGF-D and HER4 in heart failure patients decrease after heart transplantation in association with improved haemodynamics

Receptor tyrosine kinases (RTKs) are implicated in cardiovascular growth and remodelling. We aimed to identify the plasma levels of RTKs and related proteins and their association with haemodynamic alterations in heart failure (HF) and related pulmonary hypertension (PH) following heart transplantation (HT). Using proximity extension assay, 28 RTKs and related proteins were analysed in plasma from 20 healthy controls and 26 HF patients before and 1-year after HT. In end-stage HF, out of 28 RTKs, plasma vascular endothelial growth factor-D (VEGF-D) and human epidermal growth factor-4 (HER4) were elevated compared to controls (p < 0.001), but decreased (p < 0.0001) and normalised after HT. Following HT, plasma changes (Δ) of VEGF-D correlated with Δmean pulmonary artery pressure (rs = 0.65, p = 0.00049), Δpulmonary artery wedge pressure (rs = 0.72, p < 0.0001), Δpulmonary arterial compliance (PAC) (rs = - 0.52, p = 0.0083) and Δpulmonary vascular resistance (PVR) (rs = 0.58, p = 0.0032). ΔHER4 correlated with Δmean right atrial pressure (rs = 0.51, p = 0.012), ΔNT-proBNP (rs = 0.48, p = 0.016) and Δcardiac index (rs = - 0.56, p = 0.0044). In HF patients following HT, normalisation of VEGF-D reflected reversal of passive pulmonary congestion and restored PAC and PVR; whereas the normalisation of HER4 reflected decreased volume overload and improved cardiac function. The precise function of these proteins, their potential clinical use and pathophysiological relation in HF and related PH remain to be elucidated.

Prolargin and matrix metalloproteinase-2 in heart failure after heart transplantation and their association with haemodynamics

Aims

Remodelling of the extracellular matrix (ECM) is a key mechanism involved in the development and progression of heart failure (HF) but also functional in associated pulmonary hypertension (PH). Our aim was to identify plasma ECM proteins associated to end‐stage HF and secondary PH in relation to haemodynamics, before and after heart transplantation (HT).

Methods and results

Twenty ECM plasma proteins were analysed with proximity extension assay in 20 controls and 26 HF patients pre‐HT and 1 year post‐HT. Right heart catherization haemodynamics were assessed in the patients during the preoperative evaluation and at the 1 year follow‐up post‐HT. Plasma levels of prolargin and matrix metalloproteinase‐2 (MMP‐2) were elevated (P < 0.0001) in HF patients compared with controls and decreased (P < 0.0001) post‐HT towards controls' levels. The decrease in prolargin post‐HT correlated with improved mean right atrial pressure (r_s = 0.63; P = 0.00091), stroke volume index (r_s = −0.73; P < 0.0001), cardiac index (r_s = −0.64; P = 0.00057), left ventricular stroke work index (r_s = −0.49; P = 0.015), and N‐terminal pro brain natriuretic peptide (r_s = 0.7; P < 0.0001). The decrease in MMP‐2 post‐HT correlated with improved mean pulmonary artery pressure (r_s = 0.58; P = 0.0025), mean right atrial pressure (r_s = 0.56; P = 0.0046), pulmonary artery wedge pressure (r_s = 0.48; P = 0.016), and N‐terminal pro brain natriuretic peptide (r_s = 0.56; P = 0.0029).

Conclusions

The normalization pattern in HF patients of plasma prolargin and MMP‐2 post‐HT towards controls' levels and their associations with improved haemodynamics indicate that prolargin and MMP‐2 may reflect, in part, the aberrant ECM remodelling involved in the pathophysiology of HF and associated PH. Their potential clinical use as biomarkers or targets for future therapy in HF and related PH remains to be investigated.