Prognostic impact of hypochromic erythrocytes in patients with pulmonary arterial hypertension

No genetic causal association between iron status and pulmonary artery hypertension: Insights from a two-sample Mendelian randomization

To explore the genetic causal association between pulmonary artery hypertension (PAH) and iron status through Mendelian randomization (MR), we conducted MR analysis using publicly available genome-wide association study (GWAS) summary data. Five indicators related to iron status (serum iron, ferritin, total iron binding capacity (TIBC), soluble transferrin receptor (sTfR), and transferrin saturation) served as exposures, while PAH was the outcome. The genetic causal association between these iron status indicators and PAH was assessed using the inverse variance weighted (IVW) method. Cochran's Q statistic was employed to evaluate heterogeneity. We assessed pleiotropy using MR-Egger regression and MR-Presso test. Additionally, we validated our results using the Weighted median, Simple mode, and Weighted mode methods. Based on the IVW method, we found no causal association between iron status (serum iron, ferritin, TIBC, sTfR, and transferrin saturation) and PAH (p β > 0.05). The Weighted median, Simple mode, and Weighted mode methods showed no potential genetic causal association (p β > 0.05 in the three analyses). Additionally, no heterogeneity or horizontal pleiotropy was detected in any of the analyses. Our results show that there are no genetic causal association between iron status and PAH.

Low-frequency ultrasound for pulmonary hypertension therapy

BACKGROUND

Currently, there are no reliable clinical tools that allow non-invasive therapeutic support for patients with pulmonary arterial hypertension. This study aims to propose a low-frequency ultrasound device for pulmonary hypertension therapy and to demonstrate its potential.

METHODS

A novel low-frequency ultrasound transducer has been developed. Due to its structural properties, it is excited by higher vibrational modes, which generate a signal capable of deeply penetrating biological tissues. A methodology for the artificial induction of pulmonary hypertension in sheep and for the assessment of lung physiological parameters such as blood oxygen concentration, pulse rate, and pulmonary blood pressure has been proposed.

RESULTS

The results showed that exposure of the lungs to low-frequency ultrasound changed physiological parameters such as blood oxygen concentration, pulse rate and blood pressure. These parameters are most closely related to indicators of pulmonary hypertension (PH). The ultrasound exposure increased blood oxygen concentration over a 7-min period, while pulse rate and pulmonary blood pressure decreased over the same period. In anaesthetised sheep exposed to low-frequency ultrasound, a 10% increase in SpO2, a 10% decrease in pulse rate and an approximate 13% decrease in blood pressure were observed within 7 min.

CONCLUSIONS

The research findings demonstrate the therapeutic efficiency of low-frequency ultrasound on hypertensive lungs, while also revealing insights into the physiological aspects of gas exchange within the pulmonary system.

Iron deficiency in pulmonary vascular disease: pathophysiological and clinical implications

AIMS

Iron deficiency is common in pulmonary hypertension, but its clinical significance and optimal definition remain unclear.

METHODS AND RESULTS

Phenotypic data for 1028 patients enrolled in the Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics study were analyzed. Iron deficiency was defined using the conventional heart failure definition and also based upon optimal cut-points associated with impaired peak oxygen consumption (peakVO2), 6-min walk test distance, and 36-Item Short Form Survey (SF-36) scores. The relationships between iron deficiency and cardiac and pulmonary vascular function and structure and outcomes were assessed. The heart failure definition of iron deficiency endorsed by pulmonary hypertension guidelines did not identify patients with reduced peakVO2, 6-min walk test, and SF-36 (P > 0.208 for all), but defining iron deficiency as transferrin saturation (TSAT) <21% did. Compared to those with TSAT ≥21%, patients with TSAT <21% demonstrated lower peakVO2 [absolute difference: -1.89 (-2.73 to -1.04) mL/kg/min], 6-min walk test distance [absolute difference: -34 (-51 to -17) m], and SF-36 physical component score [absolute difference: -2.5 (-1.3 to -3.8)] after adjusting for age, sex, and hemoglobin (all P < 0.001). Patients with a TSAT <21% had more right ventricular remodeling on cardiac magnetic resonance but similar pulmonary vascular resistance on catheterization. Transferrin saturation <21% was also associated with increased mortality risk (hazard ratio 1.63, 95% confidence interval 1.13-2.34; P = 0.009) after adjusting for sex, age, hemoglobin, and N-terminal pro-B-type natriuretic peptide.

CONCLUSION

The definition of iron deficiency in the 2022 European Society of Cardiology (ESC)/European Respiratory Society (ERS) pulmonary hypertension guidelines does not identify patients with lower exercise capacity or functional status, while a definition of TSAT <21% identifies patients with lower exercise capacity, worse functional status, right heart remodeling, and adverse clinical outcomes.

Hypochromic red cells as a prognostic indicator of survival among patients with systemic sclerosis screened for pulmonary hypertension

BACKGROUND

Patients with systemic sclerosis (SSc) are frequently affected by iron deficiency, particularly those with pulmonary hypertension (PH). The first data indicate the prognostic importance of hypochromic red cells (% HRC) > 2% among patients with PH. Hence, the objective of our study was to investigate the prognostic value of % HRC in SSc patients screened for PH.

METHODS

In this retrospective, single-center cohort study, SSc patients with a screening for PH were enrolled. Clinical characteristics and laboratory and pulmonary functional parameters associated with the prognosis of SSc were analyzed using uni- and multivariable analysis.

RESULTS

From 280 SSc patients screened, 171 could be included in the analysis having available data of iron metabolism (81% female, 60 ± 13 years of age, 77% limited cutaneous SSc, 65 manifest PH, and 73 pulmonary fibrosis). The patients were followed for 2.4 ± 1.8 (median 2.4) years. HRC > 2% at baseline was significantly associated with worse survival in the uni- (p = 0.018) and multivariable (p = 0.031) analysis independent from the presence of PH or pulmonary parenchymal manifestations. The combination of HRC > 2% and low diffusion capacity for carbon monoxide (DLCO) ≤ 65% predicted was significantly associated with survival (p < 0.0001).

CONCLUSION

This is the first study reporting that HRC > 2% is an independent prognostic predictor of mortality and can possibly be used as a biomarker among SSc patients. The combination of HRC > 2% and DLCO ≤ 65% predicted could serve in the risk stratification of SSc patients. Larger studies are required to confirm these findings.

The role of iron in chronic inflammatory diseases: from mechanisms to treatment options in anemia of inflammation

Anemia of inflammation (AI) is a highly prevalent comorbidity in patients affected by chronic inflammatory disorders, such as chronic kidney disease, inflammatory bowel disease, or cancer, that negatively affect disease outcome and quality of life. The pathophysiology of AI is multifactorial, with inflammatory hypoferremia and iron-restricted erythropoiesis playing a major role in the context of disease-specific factors. Here, we review the recent progress in our understanding of the molecular mechanisms contributing to iron dysregulation in AI, the impact of hypoferremia and anemia on the course of the underlying disease, and (novel) therapeutic strategies applied to treat AI.