Sex-Related Aspects of Biomarkers in Cardiac Disease

Analytical and clinical performance evaluation of a new NT-proBNP assay

BACKGROUND

The study evaluated the performance of the Mindray N-terminal pro-B-type natriuretic peptide (NT-proBNP) in a healthy population in China, focusing on creating a reference range for future clinical applications adjusted according to different demographics.

METHODS

The study measured NT-proBNP in 2277 healthy individuals. We analyzed age and sex-stratified data, performed precision, accuracy, linearitcvy, and detection limit studies, and evaluated method comparison and consistency between Roche and Mindray assays on 724 serum samples. We used Excel 2010, Medcalc, and GraphPad Prism 9.

RESULTS

In males, the 97.5th centile NT-proBNP concentration at age < 45, 45 to 54, 55 to 64, 65 to 74 and ≧ 75 were 89.4 ng/L, 126 ng/L, 206 ng/L, 386 ng/L and 522 ng/L, respectively. In females, the concentration of NT-proBNP at the same age was 132 ng/L, 229 ng/L, 262 ng/L, 297 ng/L and 807 ng/L, respectively. The repeatability precision coefficient of variation (CV%) for NT-proBNP was between 0.86 and 1.65 in analytical performance. In contrast, the reproducibility precision (CV%) for NT-proBNP was between 1.52 and 3.22, respectively. The study found a bias of accuracy of 3.73% in low-value samples (concentration: 148.69) and 7.31% in high-value samples (concentration: 1939.08). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 125 ng/L were 96.6%, 92.3%, 84.2%, and 98.5%, respectively. In contrast, those of 300 ng/L were 94.0%, 98.2%, 95.7% and 97.5%, respectively.

CONCLUSIONS

The Mindray NT-proBNP assay showed increased levels in both males and females with age, with higher levels in women. It performs well and aligns with manufacturer specifications. We recommend adjusting cutoff values based on demographic factors.

Characteristics and outcomes of patients with symptomatic chronic myocardial injury in a Tanzanian emergency department: A prospective observational study

BACKGROUND

Chronic myocardial injury is a condition defined by stably elevated cardiac biomarkers without acute myocardial ischemia. Although studies from high-income countries have reported that chronic myocardial injury predicts adverse prognosis, there are no published data about the condition in sub-Saharan Africa.

METHODS

Between November 2020 and January 2023, adult patients with chest pain or shortness of breath were recruited from an emergency department in Moshi, Tanzania. Medical history and point-of-care troponin T (cTnT) assays were obtained from participants; those whose initial and three-hour repeat cTnT values were abnormally elevated but within 11% of each other were defined as having chronic myocardial injury. Mortality was assessed thirty days following enrollment.

RESULTS

Of 568 enrolled participants, 81 (14.3%) had chronic myocardial injury, 73 (12.9%) had acute myocardial injury, and 412 (72.5%) had undetectable cTnT values. Of participants with chronic myocardial injury, the mean (± sd) age was 61.5 (± 17.2) years, and the most common comorbidities were CKD (n = 65, 80%) and hypertension (n = 60, 74%). After adjusting for CKD, thirty-day mortality rates (38% vs. 36%, aOR 1.03, 95% CI: 0.52-2.03, p = 0.931) were similar between participants with chronic myocardial injury and those with acute myocardial injury, but significantly greater (38% vs. 13.6%, aOR 3.63, 95% CI: 1.98-6.65, p<0.001) among participants with chronic myocardial injury than those with undetectable cTnT values.

CONCLUSION

In Tanzania, chronic myocardial injury is a poor prognostic indicator associated with high risk of short-term mortality. Clinicians practicing in this region should triage patients with stably elevated cTn levels in light of their increased risk.

Sex Differences in Coronary Artery Disease: Insights From the KoRean wOmen'S chest pain rEgistry (KoROSE)

Interest in sex differences in coronary artery disease (CAD) has been steadily increasing. Concurrently, most of the data on these differences have primarily been Western-oriented. The KoRean wOmen'S chest pain rEgistry (KoROSE), started in 2011, has since published numerous research findings. This review aims to summarize the reported differences between men and women in CAD, integrating data from KoROSE. Cardiovascular risk in postmenopausal women escalates dramatically due to the decrease in estrogen levels, which normally offer cardiovascular protective effects. Lower estrogen levels can lead to abdominal obesity, insulin resistance, increased blood pressure, and endothelial dysfunction in older women. Upon analyzing patients with CAD, women are typically older and exhibit more cardiovascular risk factors than men. Diagnosing CAD in women tends to be delayed due to their symptoms being more atypical than men's. While in-hospital outcome was similar between sexes, bleeding complications after percutaneous coronary intervention occur more frequently in women. The differences in long-term prognosis for CAD patients between men and women are still a subject of ongoing debate. Pregnancy and reproductive factors also play a significant role as risk factors for cardiovascular disease in women. A notable sex disparity exists, with women found to use fewer cardiovascular protective drugs and undergo fewer interventional or surgical procedures than men. Additionally, women participate less frequently than men in clinical research. Through concerted efforts to increase awareness of sex differences and mitigate sex disparity, personalized treatment can be provided. This approach can ultimately improve patient prognosis.

Sex-Related Differences in Heart Failure Diagnosis

PURPOSE OF REVIEW

The literature on the importance of sex in heart failure diagnosis is scarce. This review aims to summarize current knowledge on sex differences regarding the diagnosis of heart failure.

RECENT FINDINGS

Comorbidities are frequent in patients with heart failure, and their prevalence differs between sexes; some differences in symptomatology and diagnostic imaging techniques were also found. Biomarkers also usually show differences between sexes but are not significant enough to establish sex-specific ranges. This article outlines current information related to sex differences in HF diagnosis. Research in this field remains to be done. Maintaining a high diagnostic suspicion, actively searching for the disease, and considering the sex is relevant for early diagnosis and better prognosis. In addition, more studies with equal representation are needed.

Features of the Metabolisms of Cardiac Troponin Molecules-Part 1: The Main Stages of Metabolism, Release Stage

Cardiac troponins (cTns) have long been the most valuable and specific biomarkers for detecting ischemic myocardial cells (MCs) injury, which is one of the key signs of myocardial infarction (MI). Modern methods (highly sensitive and ultra-sensitive immunoassays (hs-cTns)) of detection are an important and indispensable tool for the early diagnosis of MI and the choice of patient management protocols. Timely diagnosis of MI can significantly improve the prognosis of patients. However, in real clinical practice, doctors often face a significant problem when using cTns-the difficulty of differential diagnosis due to frequent and unexplained increases in the concentration of cTns in blood serum. In addition, there is conflicting information that may potentially affect the diagnostic capabilities and value of cTns: the influence of certain biological factors (diurnal rhythm, gender and age) on serum cTns levels; extra-cardiac expression of cTns; the possibilities of non-invasive diagnosis of MI; and other pathological conditions that cause non-ischemic injury to MCs. To solve these problems, it is necessary to concentrate on studying the metabolism of cTns. The review of our current knowledge about cTns metabolism consists of two parts. In this (first) part of the manuscript, the main stages of cTns metabolism are briefly described and the mechanisms of cTns release from MCs are considered in detail.

Ischemic preconditioning protects the heart against ischemia-reperfusion injury in chronic kidney disease in both males and females

BACKGROUND

Uremic cardiomyopathy is a common cardiovascular complication of chronic kidney disease (CKD) characterized by left ventricular hypertrophy (LVH) and fibrosis enhancing the susceptibility of the heart to acute myocardial infarction. In the early stages of CKD, approximately 60% of patients are women. We aimed to investigate the influence of sex on the severity of uremic cardiomyopathy and the infarct size-limiting effect of ischemic preconditioning (IPRE) in experimental CKD.

METHODS

CKD was induced by 5/6 nephrectomy in 9-week-old male and female Wistar rats. Two months later, serum and urine laboratory parameters were measured to verify the development of CKD. Transthoracic echocardiography was performed to assess cardiac function and morphology. Cardiomyocyte hypertrophy and fibrosis were measured by histology. Left ventricular expression of A- and B-type natriuretic peptides (ANP and BNP) were measured by qRT-PCR and circulating BNP level was measured by ELISA. In a subgroup of animals, hearts were perfused according to Langendorff and were subjected to 35 min global ischemia and 120 min reperfusion with or without IPRE (3 × 5 min I/R cycles applied before index ischemia). Then infarct size or phosphorylated and total forms of proteins related to the cardioprotective RISK (AKT, ERK1,2) and SAFE (STAT3) pathways were measured by Western blot.

RESULTS

The severity of CKD was similar in males and females. However, CKD males developed more severe LVH compared to females as assessed by echocardiography. Histology revealed cardiac fibrosis only in males in CKD. LV ANP expression was significantly increased due to CKD in both sexes, however, LV BNP and circulating BNP levels failed to significantly increase in CKD. In both sexes, IPRE significantly decreased the infarct size in both the sham-operated and CKD groups. IPRE significantly increased the phospho-STAT3/STAT3 ratio in sham-operated but not in CKD animals in both sexes. There were no significant differences in phospho-AKT/AKT and phospho-ERK1,2/ERK1,2 ratios between the groups.

CONCLUSION

The infarct size-limiting effect of IPRE was preserved in both sexes in CKD despite the more severe uremic cardiomyopathy in male CKD rats. Further research is needed to identify crucial molecular mechanisms in the cardioprotective effect of IPRE in CKD.

Immunity, Sex Hormones, and Environmental Factors as Determinants of COVID-19 Disparity in Women

The current coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome virus 2 (SARS-CoV-2), has resulted in a major global pandemic, causing extreme morbidity and mortality. Few studies appear to suggest a significant impact of gender in morbidity and mortality, where men are reported at a higher risk than women. The infectivity, transmissibility, and varying degree of disease manifestation (mild, modest, and severe) in population studies reinforce the importance of a number of genetic and epigenetic factors, in the context of immune response and gender. The present review dwells on several contributing factors such as a stronger innate immune response, estrogen, angiotensin-converting enzyme 2 gene, and microbiota, which impart greater resistance to the SARS-CoV-2 infection and disease progression in women. In addition, the underlying importance of associated microbiota and certain environmental factors in gender-based disparity pertaining to the mortality and morbidity due to COVID-19 in women has also been addressed.

MicroRNA-181b Serves as a Circulating Biomarker and Regulates Inflammation in Heart Failure

Heart failure (HF) is the typical terminal stage of cardiac diseases involving inflammatory states. The function of microRNAs (miRNAs) in the progress of HF remains poorly understood. In this study, real-time PCR results showed a decreased expression of miRNA-181b (miR-181b) in HF patients compared with healthy individuals. Besides, miR-181b expressions were negatively correlated with hypersensitive C-reactive protein (hsCRP) levels in the serum of HF patients. Receiver operator characteristic (ROC) curve analysis showed that miR-181b was a diagnostic predictor of HF, and the area under the curve was 0.970 (DCM-induced HF group) and 0.962 (ICM-induced HF group). Strikingly, in HF rats induced by isoproterenol (ISO), the expression of miR-181b of heart tissue was suppressed before tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) increase, as revealed by western blot and real-time PCR. Besides, the overexpression of miR-181b also decreased the expression of TNF-α, IL-1β, and IL-6 in lipopolysaccharide- (LPS-) induced neonatal cardiomyocytes. In conclusion, our results revealed that miR-181b might be a potential biomarker for HF and provided a novel target for anti-inflammatory therapy.

Sex-differences in circulating biomarkers during acute myocardial infarction: An analysis from the SWEDEHEART registry

BACKGROUND

Sex-differences in the pathobiology of myocardial infarction are well established but incompletely understood. Improved knowledge on this topic may help clinicians to improve management of men and women with myocardial infarction.

METHODS

In this registry-based cohort study (SWEDEHEART), we analyzed 175 circulating biomarkers reflecting various pathobiological axes in 856 men and 243 women admitted to Swedish coronary care units because of myocardial infarction. Two multimarker panels were applied (Proximity Extension Assay [Olink Bioscience], Multiple Reaction Monitoring mass spectrometry). Lasso analysis (penalized logistic regression), multiple testing-corrected Mann-Whitney tests and Cox regressions were used to assess sex-differences in the concentrations of these biomarkers and their implications on all-cause mortality and major adverse events (median follow-up up to 6.6 years).

RESULTS

Biomarkers provided a very high discrimination between both sexes, when considered simultaneously (c-statistics 0.972). Compared to women, men had higher concentrations of six biomarkers with the most pronounced differences seen for those reflecting atherogenesis, myocardial necrosis and metabolism. Women had higher concentrations of 14 biomarkers with the most pronounced differences seen for those reflecting activation of the renin-angiotensin-aldosterone axis, inflammation and for adipokines. There were no major variations between sexes in the associations of these biomarkers with outcome.

CONCLUSIONS

Severable sex-differences exist in the expression of biomarkers in patients with myocardial infarction. While these differences had no impact on outcome, our data suggest the presence of various sex-related pathways involved in the development of coronary atherosclerosis, the progression to plaque rupture and acute myocardial damage, with a greater heterogeneity in women.

Crucial considerations: Sex differences in the epidemiology, diagnosis, treatment, and outcomes of acute pulmonary embolism in non-pregnant adult patients

Acute pulmonary embolism (PE) affects over 600,000 Americans per year and is a common diagnostic consideration among emergency department patients. Although there are well-documented differences in the diagnosis, treatment, and outcomes of cardiovascular conditions, such as ischemic heart disease and stroke, the influence of sex and gender on PE remains poorly understood. The overall age-adjusted incidence of PE is similar in women and men, but women have higher relative rates of PE during early and mid-adulthood (ages 20-40 years); whereas, men have higher rates of PE after age 60 years. Women are tested for PE at far higher rates than men, yet women who undergo computed tomography pulmonary angiography are ultimately diagnosed with PE 35%-55% less often than men. Among those diagnosed with PE, women are more likely to have severe clinical features, such as hypotension and signs of right ventricular dysfunction. When controlled for PE severity, women are less likely to receive reperfusion therapies, such as thrombolysis. Finally, women have more bleeding complications for all types of anticoagulation. Further investigation of possible sex-specific diagnostic and treatment algorithms is necessary in order to more accurately detect and treat acute PE in non-pregnant adults.

The impact of sex and gender on heart-brain axis dysfunction: current concepts and novel perspectives

The heart-brain axis (HBA) recapitulates all the circuits that regulate bidirectional flow of communication between heart and brain. Several mechanisms may underlie the interdependent relationship involving heterogeneous tissues at rest and during specific target organ injury such as myocardial infarction, heart failure, arrhythmia, stroke, mood disorders, or dementia. In-depth translational studies of the HBA dysfunction under single-organ injury should include both male and female animals to develop sex- and gender-oriented prevention, diagnosis, and treatment strategies. Indeed, sex and gender are determining factors as females and males exhibit significant differences in terms of susceptibility to risk factors, age of onset, severity of symptoms, and outcome. Despite most studies having focused on the male population, we have conducted a careful appraisal of the literature investigating HBA in females. In particular, we have (i) analyzed sex-related heart and brain illnesses, (ii) recapitulated the most significant studies simultaneously conducted on cardio- and cerebro-vascular systems in female populations, and (iii) hypothesized future perspectives for the development of a gender-based approach to HBA dysfunction. Although sex- and gender-oriented research is at its infancy, the impact of sex on HBA dysfunction is opening unexpected new avenues for managing the health of female subjects exposed to risk of lifestyle multi-organ disease.

Molecular mechanisms of sex bias differences in COVID-19 mortality

More men than women have died from COVID-19. Genes encoded on X chromosomes, and sex hormones may explain the decreased fatality of COVID-19 in women. The angiotensin-converting enzyme 2 gene is located on X chromosomes. Men, with a single X chromosome, may lack the alternative mechanism for cellular protection after exposure to SARS-CoV-2. Some Toll-like receptors encoded on the X chromosomes can sense SARS-CoV-2 nucleic acids, leading to a stronger innate immunity response in women. Both estrogen and estrogen receptor-α contribute to T cell activation. Interventional approaches including estrogen-related compounds and androgen receptor antagonists may be considered in patients with COVID-19.

Sex- and Age-Related Reference Values in Cardiology, with Annotations and Guidelines for Interpretation

The definition of "abnormal" in clinical sciences is often based on so-called reference values which point to a range that experts by some sort of consensus consider as normal when looking at biological variables. Such a level is commonly calculated by taking (twice) the standard deviation from the mean, or considering certain percentiles. The suspicion or even confirmation of a disease is then established by demonstrating that the value measured exceeds the upper or lower reference value. As is often the case, the measurement accuracy may depend on the conditions and specific method employed to collect and analyze data. This implies that, for example, data assessed by 2D echocardiography possibly differ from those obtained by MRI and therefore require modality-specific reference values. In this review we summarize reference values for the electrocardiogram, cardiac compartmental volumes, and arterial vessel size in males and females for various age groups. These values may further depend on other variables such as body size, physical training status, and ethnicity. Additional variables relevant for cardiology such as those referring to the microcirculation and biomarkers are only mentioned with reference to the pertinent literature. In general, the sex- and age-specific differences observed are often remarkable and warrant consideration in clinical practice and basic biomedical sciences.