Chronic hypoxemia increases ventricular brain natriuretic peptide precursors in neonatal swine

Efficacy of continuous positive airway pressure on NT-pro-BNP in obstructive sleep apnea patients: a meta-analysis

BACKGROUND

N-terminal probrain natriuretic peptide (NT-pro-BNP) and BNP are well-known markers for the diagnosis and prognostic of heart failure. Until now, it was not clear whether BNP levels are influenced by events occurring within Obstructive sleep apnea-hypopnea syndrome (OSAHS) with continuous positive airway pressure (CPAP).

METHODS

A thorough search in PubMed, EMBASE, Google Scholar, and Web of Science databases up to October 24, 2022, and a meta-analysis aimed to explore further accurate estimates of the effects of BNP on OSAHS after CPAP treatment to assess the strength of the evidence.

RESULTS

The forest plot outcome indicated that CPAP therapy did not change the BNP level in patients with OSAHS, with a weighted mean difference (WMD) of -0.47 (95% CI: -1.67 to 2.62; P = 0.53] based on the random effect model because of high significant heterogeneity (I² = 80%) among the studies. Subgroup analysis also explored the changes in BNP levels in patients with OSAHS. Begg's test (P = 0.835) and Egger's test (P = 0.245) suggested significant negative publication bias.

CONCLUSION

Our meta-analysis suggests that CPAP therapy does not change the BNP level in patients with OSAHS; therefore, it is not accurate to use BNP level as an index to evaluate heart function in patients with OSAHS, but more related research should be conducted.

Subclinical elevated B-type Natriuretic Peptide (BNP) indicates endothelial dysfunction contributing to hypoxia susceptibility in healthy individuals

Aims

Baseline elevated B-type Natriuretic Peptide (BNP) has been found in high altitude pulmonary edema susceptible population. Exaggerated pulmonary vascular response to hypoxia may be related to endothelial dysfunction in hypoxia susceptible. We hypothesize that baseline BNP levels can predict hypoxia susceptibility in healthy individuals.

Main methods

The pulmonary vascular response to hypoxia was compared in 35 male healthy individuals divided into two groups based on BNP levels (Group 1 ≤ 15 and Group 2 > 15 pg/ml). Acute normobaric hypoxia was administered to both the groups, to confirm hypoxia susceptibility in Group 2.

Key findings

Unlike Group 1, Group 2 had elevated post hypoxia BNP levels (26 vs 33.5 pg/ml, p = 0.002) while pulmonary artery pressure was comparable. A negative correlation with tissue oxygen consumption (delta pO₂) and compartmental fluid shift was seen in Group 1 only. Endothelial dysfunction in Group 2 resulted in reduced vascular compliance leading to elevation of mean blood pressure on acute hypoxia exposure. BNP showed a positive correlation with endothelial dysfunction in Group 2 and has been linked to pre-diabetic disorder (HbA1c 6 ± 0.44%) and may additionally represent a lower cross-sectional area of vascular bed related to vascular remodeling mediated by chronic hypoxia.

Significance

Hypoxia susceptibility in healthy individuals may be related to endothelial dysfunction that limits vascular compliance during hypoxic stress. BNP level showed positive correlation with HbA1c (r = 0.49, p = 0.04) and negative correlation with delta pO₂ (r = −0.52, p = 0.04) can predict reduced microvascular compliance due to endothelial dysfunction contributing to hypoxia susceptibility in healthy individuals. BNP levels≤15 pg/ml at sea level is indicative of hypoxia resistance.

Circulating chromogranin B levels in patients with acute respiratory failure: data from the FINNALI Study

PURPOSE

Circulating chromogranin B (CgB) levels are increased in situations characterized by systemic and myocardial stress, but whether CgB provides prognostic information in patients with acute respiratory failure (ARF) is unknown.

METHODS

We included 584 patients with ARF, defined as ventilatory support >6 h, and with blood samples available on Intensive Care Unit (ICU) admission and day 3 (n = 479). CgB levels were measured by radioimmunoassay and follow-up was 90 days.

RESULTS

One-hundred-sixty-nine patients (29%) died during follow-up. Admission CgB levels separated non-survivors from survivors: median 1234 (Q1-3 989-1742) vs. 917 (753-1224) pmol/L, respectively, p < 0.001. CgB levels on ICU admission (logarithmically transformed) were associated with time to death after adjustment for established risk indices available on ICU admission, including N-terminal pro-B-type natriuretic levels: HR 2.62 (95%C.I. 1.82-3.77), p < 0.001. Admission CgB levels also improved prognostication on top of SOFA and SAPS II scores as assessed by Cox regression analyses and the category-free net reclassification index. The area under the curve (AUC) for admission CgB levels to separate survivors and non-survivors was 0.72 (95%CI 0.67-0.76), while the AUC on day 3 was 0.60 (0.54-0.66).

CONCLUSIONS

CgB levels measured on ICU admission provided additional prognostic information to established risk indices in ARF patients.

Prognostic Value of Secretoneurin in Patients with Acute Respiratory Failure: Data from the FINNALI Study

BACKGROUND

We examined whether secretoneurin (SN), a biomarker associated with cardiomyocyte Ca2+ handling, provides prognostic information in patients with acute respiratory failure (ARF).

METHODS

We included 490 patients with ARF, defined as ventilatory support &gt;6 h, with blood samples available on admission to the intensive care unit (ICU). SN concentrations were measured by RIA.

RESULTS

A total of 209 patients (43%) were hospitalized with cardiovascular (CV)-related ARF, and 90-day mortality rates were comparable between CV- and non–CV-related ARF (n = 281): 31% vs 24%, P = 0.11. Admission SN concentrations were higher in nonsurvivors than in survivors in both CV-related (median 148 [quartile 1–3, 117–203] vs 108 [87–143] pmol/L, P &lt; 0.001) and non–CV-related ARF (139 [115–184] vs 113 [91–139] pmol/L, P &lt; 0.001). In patients with CV-related ARF, SN concentrations on ICU admission were associated with 90-day mortality [odds ratio (OR) 1.97 (95% CI, 1.04–3.73, P = 0.04)] after adjusting for established risk indices, including N-terminal-pro-B-type natriuretic peptide (NT-proBNP) concentrations. SN also improved patient classification in CV-related ARF as assessed by the net reclassification index: 0.32 (95% CI, 0.04–0.59), P = 0.03. The area under the curve (AUC) of SN to predict mortality in patients with CV-related ARF was 0.72 (95% CI, 0.65–0.79), and the AUC of NT-proBNP was 0.64 (0.56–0.73). In contrast, SN concentrations on ICU admission did not provide incremental prognostic value to established risk indices in patients with non–CV-related ARF, and the AUC was 0.67 (0.60–0.75).

CONCLUSIONS

SN concentrations measured on ICU admission provided incremental prognostic information to established risk indices in patients with CV-related ARF, but not in patients with non–CV-related ARF.

Impaired transcriptional response of the murine heart to cigarette smoke in the setting of high fat diet and obesity

Smoking and obesity are each well-established risk factors for cardiovascular heart disease, which together impose earlier onset and greater severity of disease. To identify early signaling events in the response of the heart to cigarette smoke exposure within the setting of obesity, we exposed normal weight and high fat diet-induced obese (DIO) C57BL/6 mice to repeated inhaled doses of mainstream (MS) or sidestream (SS) cigarette smoke administered over a two week period, monitoring effects on both cardiac and pulmonary transcriptomes. MS smoke (250 μg wet total particulate matter (WTPM)/L, 5 h/day) exposures elicited robust cellular and molecular inflammatory responses in the lung with 1466 differentially expressed pulmonary genes (p < 0.01) in normal weight animals and a much-attenuated response (463 genes) in the hearts of the same animals. In contrast, exposures to SS smoke (85 μg WTPM/L) with a CO concentration equivalent to that of MS smoke (~250 CO ppm) induced a weak pulmonary response (328 genes) but an extensive cardiac response (1590 genes). SS smoke and to a lesser extent MS smoke preferentially elicited hypoxia- and stress-responsive genes as well as genes predicting early changes of vascular smooth muscle and endothelium, precursors of cardiovascular disease. The most sensitive smoke-induced cardiac transcriptional changes of normal weight mice were largely absent in DIO mice after smoke exposure, while genes involved in fatty acid utilization were unaffected. At the same time, smoke exposure suppressed multiple proteome maintenance genes induced in the hearts of DIO mice. Together, these results underscore the sensitivity of the heart to SS smoke and reveal adaptive responses in healthy individuals that are absent in the setting of high fat diet and obesity.

Persistent pulmonary hypertension results in reduced tetralinoleoyl-cardiolipin and mitochondrial complex II + III during the development of right ventricular hypertrophy in the neonatal pig heart

Persistent pulmonary hypertension of the newborn (PPHN) results in right ventricular (RV) hypertrophy followed by right heart failure and an associated mitochondrial dysfunction. The phospholipid cardiolipin plays a key role in maintaining mitochondrial respiratory and cardiac function via modulation of the activities of enzymes involved in oxidative phosphorylation. In this study, changes in cardiolipin and cardiolipin metabolism were investigated during the development of right heart failure. Newborn piglets (<24 h old) were exposed to a hypoxic (10% O(2)) environment for 3 days, resulting in the induction of PPHN. Two sets of control piglets were used: 1) newborn or 2) exposed to a normoxic (21% O(2)) environment for 3 days. Cardiolipin biosynthetic and remodeling enzymes, mitochondrial complex II + III activity, incorporation of [1-(14)C]linoleoyl-CoA into cardiolipin precursors, and the tetralinoleoyl-cardiolipin pool size were determined in both the RV and left ventricle (LV). PPHN resulted in an increased heart-to-body weight ratio, RV-to-LV plus septum weight ratio, and expression of brain naturetic peptide in RV. In addition, PPHN reduced cardiolipin biosynthesis and remodeling in the RV and LV, which resulted in decreased tetralinoleoyl-cardiolipin levels and reduced complex II + III activity and protein levels of mitochondrial complexes II, III, and IV in the RV. This is the first study to examine the pattern of cardiolipin metabolism during the early development of both the RV and LV of the newborn piglet and to demonstrate that PPHN-induced alterations in cardiolipin biosynthetic and remodeling enzymes contribute to reduced tetralinoleoyl-cardiolipin and mitochondrial respiratory chain function during the development of RV hypertrophy. These defects in cardiolipin may play an important role in the rapid development of RV dysfunction and right heart failure in PPHN.

N-terminal-pro-BNP in critically ill patients with acute respiratory failure: a prospective cohort study

BACKGROUND

The aim of this study was to evaluate the prognostic value of plasma N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) in unselected critically ill patients with acute respiratory failure (ARF).

METHODS

Prospective, observational cohort study in 25 intensive care units in Finland. This study included a total of 602 patients with laboratory samples from 958 consecutive patients with ARF treated either with invasive or with non-invasive ventilatory support (the FINNALI study). Plasma NT-pro-BNP samples were drawn after the onset of ventilatory support (day 0) and on the morning of the second day.

RESULTS

The median [interquartile ranges (IQR)] NT-pro-BNP-values were significantly higher at baseline in 90-day non-survivors than the survivors, 4378 pg/ml (1400-13,943 pg/ml) vs. 1052 pg/ml (232-4076 pg/ml), respectively. The median (IQR) NT-pro-BNP values were significantly higher in patients with chronic cardiac disease or cardiac surgery than in non-cardiac patients, 1947 pg/ml (801-4687 pg/ml) vs. 417 pg/ml (153-1735 pg/ml), respectively, if renal function was normal. With deteriorating renal function, the NT-pro-BNP values showed a significant increase. The area under curve for baseline NT-pro-BNP predicting 90-day mortality was moderate: 0.718 (95% confidence interval 0.674-0.761). Baseline NT-pro-BNP over 1765 pg/ml was independently associated with 90-day mortality by logistic regression analysis (P<0.001).

CONCLUSIONS

NT-pro-BNP on admission is commonly elevated and independently associated with 90-day mortality in critically ill ARF patients. However, the routine use of NT-pro-BNP for prognostic purpose does not seem to add value to clinical data in ARF patients.

Practical application of natriuretic peptides in paediatric cardiology

It is still uncertain if cardiac natriuretic peptides are useful biomarkers in paediatric cardiology. In this review we identify four clinical scenarios in paediatric cardiology, where clinical decision-making can be difficult, and where we feel the paediatric cardiologists need additional diagnostic tools. Natriuretic peptide measurements could be that extra tool. We discuss and suggest N-terminal pro-B-type natriuretic peptide and B-type natriuretic peptide reference intervals for children without cardiovascular disease and cut-off points for the four specific paediatric heart conditions. We conclude that in premature neonates with persistent arterial ducts; in teenagers with tetralogy of Fallot and pulmonary regurgitation; and in children with heart transplants and potential allograft rejection cardiac peptides can provide the clinician with additional information, but in children with atrial septal defects the peptides are not helpful in guiding treatment or follow-up.

Natriuretic peptides in hormonal regulation of hypoxia responses

The possibility that natriuretic peptides' effects are important in hypoxia responses of vertebrates is reviewed. Both the transcription and release of natriuretic peptides are affected by oxygen tension. Furthermore, many of the effects observed in hypoxia, such as diuresis and a reduction of plasma volume, are also caused by treatment of the animal with natriuretic peptides. Also, several clinical observations about changes in natriuretic peptide levels in, e.g., sleep apnea and cyanotic congenital heart disease, are consistent with the idea that hypoxia is involved in the etiology of conditions, in which natriuretic peptide levels increase. Virtually all published information on the relationship between oxygen and natriuretic peptides is based on human studies. Because hypoxic conditions are more common in aquatic than terrestrial environments, future studies about the possible role of natriuretic peptides in hypoxia, as well as the role of hypoxia in the evolution of natriuretic peptides, including the different subtypes, should increasingly involve also aquatic organisms.

The accuracy of natriuretic peptides (brain natriuretic peptide and N-terminal pro-brain natriuretic) in the differentiation between transfusion-related acute lung injury and transfusion-related circulatory overload in the critically ill

BACKGROUND

The diagnostic workup of transfusion-related acute lung injury (TRALI) requires an exclusion of transfusion-associated circulatory overload (TACO). Brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic (NT-pro-BNP) accurately diagnosed TACO in preliminary studies that did not include patients with TRALI.

STUDY DESIGN AND METHODS

In this prospective cohort study, two critical care experts blinded to serum levels of BNP and NT-pro-BNP determined the diagnosis of TRALI, TACO, and possible TRALI based on the consensus conference definitions. The accuracy of BNP and NT-pro-BNP was assessed based on the area under the receiver operating curve (AUC).

RESULTS

Of 115 patients who developed acute pulmonary edema after transfusion, 34 were identified with TRALI, 31 with possible TRALI, and 50 with TACO. Median BNP was 375 pg per mL (interquartile range [IQR], 123 to 781 pg/mL) in TRALI, 446 pg per mL (IQR, 128 to 743 pg/mL) in possible TRALI, and 559 pg per mL (IQR, 288 to 1348 pg/mL) in TACO patients (p = 0.038). The NT-pro-BNP levels among patients with TRALI, possible TRALI, and TACO differed significantly with a median value of 1559 pg per mL (IQR, 629 to 5114 pg/mL), 2349 pg/mL (IQR, 919 to 4610 pg/mL), and 5197 pg/mL (IQR, 1695 to 15,714 pg/mL; p = 0.004), respectively. The accuracy of BNP and NT-pro-BNP to diagnose TACO was moderate with an AUC of 0.63 (95% confidence interval [CI], 0.51-0.74) and 0.70 (95% CI, 0.59 to 0.80).

CONCLUSIONS

Natriuretic peptides are of limited diagnostic value in a differential diagnosis of pulmonary edema after transfusion in the critically ill patients.