Beta 2-Microglobulin and the Severity of Coronary Stenosis in Patients With Acute Coronary Syndrome

'Evaluation of beta-2-microglobulin and neuron-specific enolase as prognostic factors in patients over 65 years of age with frailty syndrome hospitalized for acute coronary syndrome'

BACKGROUND

The aim of the study is to assess the value of beta-2-microglobulin (B2M) and neuron-specific enolase (NSE) as prognostic factors in the population of patients over 65 years of age with frailty hospitalized due to acute coronary syndrome (ACS).

METHODS

Patients aged ≥65 years with ACS were included. Assessment of frailty was carried out using the FRAIL scale. The measurement of NSE and B2M was carried out three times during hospitalization: (1) at the time of admission, (2) on the second day of hospitalization, (3) on the seventh day of hospitalization, or the day of discharge if it was before the seventh day. The primary endpoint was all-cause mortality, and the secondary endpoint was unscheduled rehospitalization.

RESULTS

Of the 127 patients, frailty was identified in 39.3%. Multivariate analysis of variance showed significantly higher levels of NSE ( P  = 0.012) and B2M ( P  < 0.001) in patients with frailty compared to the nonfrail group and significant changes in marker levels during hospitalization - decreased NSE ( P  < 0.001) and increased B2M levels ( P  < 0.001). Elevated B2M-1 level was an independent marker of the occurrence of frailty [odds ratio (OR), 1.98 (1.09-4.00); P  = 0.044], and the optimal cutoff point for the diagnosis of frailty was 2.85 mg/l [area under the curve (AUC), 0.718 (0.632-0.795)] with sensitivity 52% and specificity 84.4% ( P  < 0.001). Elevated NSE-3 level was associated with all-cause mortality, and each 1 ng/ml increase in NSE-3 increased the risk of death by 1.07-fold [OR, 1.07 (1.03-1.10]). Meanwhile, elevated B2M-3 level was associated with unscheduled rehospitalization, and each 1 mg/l increase in B2M-3 increased the risk of unscheduled rehospitalization by 1.21-fold [OR, 1.21 (1.03-1.42)]. The Harrell's C-index for all-cause mortality was higher for NSE-3 [0.820 (95% confidence interval {CI}, 0.706-0.934)] compared to frailty assessed by the FRAIL scale [0.715 (95% CI, 0.580-0.850)], which means that additional NSE-3 assessment may improve the prediction of all-cause mortality. However, Uno's C-Statistic analysis showed that the difference was not statistically significant (Pr>chi-square 0.556). Harrell's C-index for unscheduled rehospitalization was higher for frailty assessed by the FRAIL scale compared to B2M-3.

CONCLUSION

Monitoring NSE and B2M marker levels in patients over 65 years of age with frailty and ACS does not provide additional benefits in terms of prognostic ability compared to tests assessing frailty. B2M, assessed upon hospital admission and monitoring NSE and B2M levels during hospitalization may be considered in the diagnosis of frailty and risk stratification in a group of patients for whom currently available frailty diagnostic tools cannot be used.

Lifting the Veil: Characteristics, Clinical Significance, and Application of β-2-Microglobulin as Biomarkers and Its Detection with Biosensors

Because β-2-microglobulin (β₂M) is a surface protein that is present on most nucleated cells, it plays a key role in the human immune system and the kidney glomeruli to regulate homeostasis. The primary clinical significance of β₂M is in dialysis-related amyloidosis, a complication of end-stage renal disease caused by a gradual accumulation of β₂M in the blood. Therefore, the function of β₂M in kidney-related diseases has been extensively studied to evaluate its glomerular and tubular functions. Because increased β₂M shedding due to rapid cell turnover may indicate other underlying medical conditions, the possibility to use β₂M as a versatile biomarker rose in prominence across multiple disciplines for various applications. Therefore, this work has reviewed the recent use of β₂M to detect various diseases and its progress as a biomarker. While the use of state-of-the-art β₂M detection requires sophisticated tools, high maintenance, and labor cost, this work also has reported the use of biosensor to quantify β₂M over the past decade. It is hoped that a portable and highly efficient β₂M biosensor device will soon be incorporated in point-of-care testing to provide safe, rapid, and reliable test results.

Association of Beta-2-Microglobulin With Coronary Heart Disease and All-Cause Mortality in the United States General Population

Few prospective studies explored the association of beta-2-microglobulin (B2M) with coronary heart disease (CHD) mortality. The primary objective of this study was to examine the association of serum B2M with CHD and all-cause mortality. This is a prospective cohort study of a nationally representative sample of 4,885 adults, aged 40–85 years, who participated in the National Health and Nutrition Examination Survey (NHANES III) from 1988 to 1994. The relationships between B2M and CHD and all-cause mortality were estimated using Cox proportional hazards regression models. During a median follow-up of 15.5 years, 845 CHD and 3,388 all-cause deaths occurred among 4,885 participants [2,568 women (55.7%); mean (S.D.) age, 66.4 (12.5) years], respectively. In the unadjusted model, B2M concentration was strongly linearly associated with CHD and all-cause mortality (p-trend < 0.001). After adjusting multivariable factors, a positive linear association between B2M and all-cause mortality was still observed (H.R. for Q4 vs. Q1 5.90; 95% CI: 5.31–6.57; p-trend < 0.001). In the multivariable adjustment model, B2M was significantly associated with an increased risk of CHD mortality (H.R. for Q4 vs. Q1 2.72; 95% CI: 2.07–3.57; p-trend < 0.001). In the stratified analyses, the associations of B2M with CHD and all-cause mortality varied by risk factors, such as age, smoking status, and history of hypertension. The findings suggest a significant relationship between the higher serum B2M concentration and increased risk for CHD and all-cause mortality. Further large-scale follow-up studies are also needed to validate this association.

A New Score for Determining Thrombus Burden in STEMI Patients: The MAPH Score

Aim

to investigate whether the MAPH score, which is a new score that combines blood viscosity biomarkers such as mean platelet volume (MPV), total protein and hematocrit, can be used to predict thrombus burden in ST-segment elevation myocardial infarction (STEMI) patients.

Methods

A total of 473 consecutive patients with STEMI were included in the study. Intracoronary tirofiban/abciximab infusion was applied to patients with thrombus load ≥3 and these patients (n = 71) were defined as the patient group with high thrombus load. MPV, age, hematocrit and total protein values of the patients were recorded. High shear rate (HSR) and low shear rate (LSR) were calculated from total protein and hematocrit values. Cut-off values were determined for high thrombus load by using Youden index, and score was determined as 0 or 1 according to cut-offs. The sum of the scores was calculated as the MAPH score.

Results

The mean age of the patients included in the study was 59.6 ± 12.6 (n = 354 male, 74.8%). There was no difference between the groups in terms of gender, HT and DM (P = .127, P = .402 and P = .576, respectively). In the group with high thrombus load; total protein, MPV and hematocrit values were higher (P < .001, P = .001 and P = .03, respectively). Comparison of receiver operating characteristic (ROC) curve analysis revealed that the MAPH score had better performance in predicting higher thrombus load than both other self-containing parameters and HSR and LSR.

Conclusion

The MAPH score may be a new score that can be used to determine thrombus burden in STEMI patients.

Contradictions between DAPT and PRECISE-DAPT scores with the severity of coronary lesion in acute coronary syndrome

This study aimed to identify the correlation of contradiction between DAPT score and PRECISE-DAPT score with the severity of coronary lesion in acute coronary syndromes (ACS).In total, 458 patients with ACS after a percutaneous coronary intervention (PCI) who had tolerated 1-year uneventful dual antiplatelet therapy (DAPT) were enrolled and divided into groups based on the Gensini score, number of stenosed vessels, and left main (LM) disease. Both DAPT score and PRECISE-DAPT score were calculated and the proportion of patients receiving conflicting recommendations from each score was compared among the groups.DAPT score as well as the proportion of patients with DAPT score ≥2 were associated with the Gensini score and the number of stenosed vessels. Similarly, PRECISE-DAPT score as well as the proportion of patients with PRECISE-DAPT score ≥25 were associated with the Gensini score and the number of stenosed vessels. The proportion of patients with DAPT score ≥2 along with PRECISE-DAPT score ≥25 were associated with Gensini score, but they had no significant association with the number of stenosed vessels (P = .006 and P = .075, respectively). None of those aforementioned items were associated with LM disease.The inconsistencies of DAPT scores and PRECISE-DAPT scores are frequent and associated with the severity of coronary disease, represented by the Gensini score. Appropriate clinical decisions should be individualized.

Regenerative Capacity of Endogenous Factor: Growth Differentiation Factor 11; a New Approach of the Management of Age-Related Cardiovascular Events

Aging is a complicated pathophysiological process accompanied by a wide array of biological adaptations. The physiological deterioration correlates with the reduced regenerative capacity of tissues. The rejuvenation of tissue regeneration in aging organisms has also been observed after heterochronic parabiosis. With this model, it has been shown that exposure to young blood can rejuvenate the regenerative capacity of peripheral tissues and brain in aged animals. An endogenous compound called growth differentiation factor 11 (GDF11) is a circulating negative regulator of cardiac hypertrophy, suggesting that raising GDF11 levels could potentially treat or prevent cardiac diseases. The protein GDF11 is found in humans as well as animals. The existence of endogenous regulators of regenerative capacity, such as GDF11, in peripheral tissues and brain has now been demonstrated. It will be important to investigate the mechanisms with therapeutic promise that induce the regenerative effects of GDF11 for a variety of age-related diseases.

Correlations of DAPT score and PRECISE-DAPT score with the extent of coronary stenosis in acute coronary syndrome

Dual antiplatelet therapy (DAPT) score and PRECISE-DAPT score were recommended for decision making of optimal DAPT in discriminating the risk of thrombosis and bleeding. But the relationships between 2 scoring tools with the extent of coronary stenosis have not been established.We retrospectively enrolled 359 patients of acute coronary syndrome (ACS) who received percutaneous coronary intervention. Both DAPT score and PRECISE-DAPT score were calculated, and patients were divided by their recommended cut-offs. Gensini score and triple-vessel disease (3-VD) were chosen to evaluate the severity of coronary stenosis.Overall, 54.9% and 10.0% of the patients had higher DAPT score (≥2) or PRECISE-DAPT score (≥25). Patients with higher DAPT score had increased stent counts, total length of stents, Gensini score, and proportion of 3-VD, but decreased minimum diameter of stent. But these differences were not found in PRECISE-DAPT subgroups. When divided into quartiles of both scoring systems, the highest Gensini score and proportions of 3-VD were found in the fourth quartile of both DAPT score and PRECISE-DAPT score. Moreover, both DAPT score and PRECISE-DAPT score were independent risk factors of Gensini score after adjustment (P < .001 and P = .047). Furthermore, an increase of 1 point of DAPT score and 5 points of PRECISE-DAPT score resulted by 51% (odds ratios [OR]: 1.51, 95% confidence interval [CI]:1.19-1.91, P = .001) and 34% (OR: 1.34, 95% CI: 1.11-1.62, P = .003) increase in risk of 3-VD after adjustment.Both DAPT score and PRECISE-DAPT score were independently associated with the degree of coronary stenosis in patients with ACS.

Mechanical stresses induce paracrine β-2 microglobulin from cardiomyocytes to activate cardiac fibroblasts through epidermal growth factor receptor

By employing a proteomic analysis on supernatant of mechanically stretched cardiomyocytes, we found that stretch induced a significantly high level of β-2 microglobulin (β2M), a non-glycosylated protein, which is related to inflammatory diseases but rarely known in cardiovascular diseases. The present data showed that serum β2M level was increased in patients with hypertension and further increased in patients with chronic heart failure (HF) as compared with control group, and the high level of serum β2M level correlated to cardiac dysfunction in these patients. In pressure overload mice model by transverse aortic constriction (TAC), β2M levels in serum and heart tissue increased progressively in a time-dependent manner. Exogenous β2M showed pro-fibrotic effects in cultured cardiac fibroblasts but few effects in cardiomyocytes. Adeno-associated virus 9 (AAV9)-mediated knockdown of β2M significantly reduced cardiac β2M level and inhibited myocardial fibrosis and cardiac dysfunction but not cardiac hypertrophy at 4 weeks after TAC. In vitro, mechanical stretch induced the rapid secretion of β2M mainly from cardiomyocytes by activation of extracellular-regulated protein kinase (ERK). Conditional medium (CM) from mechanically stretched cardiomyocytes activated cultured cardiac fibroblasts, and the effect was partly abolished by CM from β2M-knockdown cardiomyocytes. In vivo, knockdown of β2M inhibited the increase in phosphorylation of epidermal growth factor receptor (EGFR) induced by TAC. In cultured cardiac fibroblasts, inhibition of EGFR significantly attenuated the β2M-induced the activation of EGFR and pro-fibrotic responses. The present study suggests that β2M is a paracrine pro-fibrotic mediator and associated with cardiac dysfunction in response to pressure overload.