Human Angiotensin I-Converting Enzyme Produced by Different Cells: Classification of the SERS Spectra with Linear Discriminant Analysis.

Angiotensin I-converting enzyme (ACE) is a peptidase widely presented in human tissues and biological fluids. ACE is a glycoprotein containing 17 potential N-glycosylation sites which can be glycosylated in different ways due to post-translational modification of the protein in different cells. For the first time, surface-enhanced Raman scattering (SERS) spectra of human ACE from lungs, mainly produced by endothelial cells, ACE from heart, produced by endothelial heart cells and miofibroblasts, and ACE from seminal fluid, produced by epithelial cells, have been compared with full assignment. The ability to separate ACEs' SERS spectra was demonstrated using the linear discriminant analysis (LDA) method with high accuracy. The intervals in the spectra with maximum contributions of the spectral features were determined and their contribution to the spectrum of each separate ACE was evaluated. Near 25 spectral features forming three intervals were enough for successful separation of the spectra of different ACEs. However, more spectral information could be obtained from analysis of 50 spectral features. Band assignment showed that several features did not correlate with band assignments to amino acids or peptides, which indicated the carbohydrate contribution to the final spectra. Analysis of SERS spectra could be beneficial for the detection of tissue-specific ACEs.

Prognostic Value of Characterizing Myocardial Tissue by Cardiac MRI with T1 Mapping in HFpEF Patients: A Systematic Review and Meta-Analysis.

Objectives: Our study aimed at conducting a systematic review and meta-analysis, with the objective of evaluating the prognostic value of T1 mapping techniques via cardiac magnetic resonance (CMR) in heart failure with preserved ejection fraction (HFpEF) patients. Materials and methods: The protocol was prospectively registered in the international prospective register of systematic reviews PROSPERO (registration number CRD42022300991). We searched PubMed, Google Scholar, and EMBASE for studies examining the prognostic value of characterizing myocardial tissue via CMR imaging with T1 mapping in HFpEF. Hazard ratios (HRs) for uniformly defined predictors were pooled for meta-analysis. Results: In total, 7 studies were retrieved from 351 publications for this systematic review and meta-analysis. A total of 1930 patients (mean age of 69.4 years, mean follow-up duration of 25.6 months) was included in the analysis. The meta-analysis demonstrated that higher extracellular volume (ECV) was associated with an increased risk of death and/or hospitalization with heart failure (HF) (HR:1.12; 95% CI: 1.06−1.18; p < 0.0001). After adjusting for baseline characteristics, the higher extent of ECV remained strongly associated with the risk of death and/or hospitalization with HF (HRadjusted: 1.08; 95% CI: 1.04−1.13; p = 0.0001). However, no significant association of native T1 value with risk of death or adverse cardiovascular events was found (HR:1.01; 95% CI: 1.00−1.02; p = 0.21). Conclusion: Assessment of ECV via CMR has an important prognostic value for outcomes of death and/or hospitalization with HF, and can therefore be used as an effective tool for risk stratification of patients with HFpEF.

Should We Monitor Glucose and Biomarkers in Diabetics over Heart Surgery?

Hyperglycemia is associated with adverse outcomes after coronary artery bypass grafting (CABG). While there is a consensus that blood glucose control may benefit patients undergoing CABG, the role of biomarkers, optimal method, and duration of such monitoring are still unclear. The aim of this study is to define the efficacy of a continuous glucose monitoring system (CGMS) and link it to pro-inflammatory biomarkers while on insulin pump therapy in diabetic patients undergoing CABG. We prospectively assessed CGMS for 72 h in 105 patients including 52 diabetics undergoing isolated CABG. In diabetics, CGMS was connected to an insulin pump for precise glucose control. On top of conventional biomarkers (HbA1C, lipid profile), high sensitive C-reactive protein (hs-CRP), Regulated upon Activation Normal T cell Expressed and presumably Secreted (RANTES), and leptin levels were collected before surgery, 1 h, 12 h, 7 days, and at 1 year after CABG. Overall, CGMS revealed high glucose independently from underlying diabetes during first 48 h following CABG but was higher (p < 0.05) in diabetics. The insulin pump improved glycemic control over early follow-up (72 h) post-CABG. There were no hypoglycemic episodes in patients on insulin pump therapy and those receiving bolus insulin therapy. We revealed a lower rate of postpericardiotomy syndrome (PCTS) in patients on insulin pump therapy compared to patients prescribed bolus insulin therapy in the early postoperative period (p = 0.03). Hs-CRP and RANTES levels were lower in patients with T2DM on insulin pump therapy compared to patients prescribed bolus insulin therapy in the early postoperative period (p < 0.05). It is most likely due to the fact that insulin pump therapy decreases systemic inflammatory response. Further controlled trials should assess whether CGMS improves outcomes after cardiac surgery.

Conformational fingerprint of blood and tissue ACEs: Personalized approach.

BACKGROUND: The pattern of binding of monoclonal antibodies (mAbs) to 18 epitopes on human angiotensin I-converting enzyme (ACE)-"conformational fingerprint of ACE"-is a sensitive marker of subtle conformational changes of ACE due to mutations, different glycosylation in various cells, the presence of ACE inhibitors and specific effectors, etc. METHODOLOGY/PRINCIPAL FINDINGS: We described in detail the methodology of the conformational fingerprinting of human blood and tissue ACEs that allows detecting differences in surface topography of ACE from different tissues, as well detecting inter-individual differences. Besides, we compared the sensitivity of the detection of ACE inhibitors in the patient's plasma using conformational fingerprinting of ACE (with only 2 mAbs to ACE, 1G12 and 9B9) and already accepted kinetic assay and demonstrated that the mAbs-based assay is an order of magnitude more sensitive. This approach is also very effective in detection of known (like bilirubin and lysozyme) and still unknown ACE effectors/inhibitors which nature and set could vary in different tissues or different patients. CONCLUSIONS/SIGNIFICANCE: Phenotyping of ACE (and conformational fingerprinting of ACE as a part of this novel approach for characterization of ACE) in individuals really became informative and clinically relevant. Appreciation (and counting on) of inter-individual differences in ACE conformation and accompanying effectors make the application of this approach for future personalized medicine with ACE inhibitors more accurate. This (or similar) methodology can be applied to any enzyme/protein for which there is a number of mAbs to its different epitopes.

Body Mass Index and Plasma P-Selectin before Coronary Stenting Predict High Residual Platelet Reactivity at 6 Months on Dual Antiplatelet Therapy.

BACKGROUND: High residual platelet reactivity (HRPR) during dual antiplatelet therapy (DAPT) may impact clinical outcomes following percutaneous coronary interventions (PCI). However, whether any biomarkers assessed before PCI at DAPT loading may predict delayed maintenance HRPR is not clear. OBJECTIVE: The aim of this study was to determine whether conventional clinical or laboratory indices at loading before stenting may predict HRPR at 6 months of maintenance DAPT. METHODS: The study was designed on a single-center prospective cohort, and included 94 pre-PCI patients. All patients underwent elective PCI with drug-eluting stent implantation, and received DAPT with aspirin and clopidogrel. Platelet reactivity was assessed with 5 µmol/L of adenosine diphosphate-induced light transmission aggregometry before PCI, but after 24 h of DAPT loading, and repeated at 6 months. Baseline clinical characteristics, CYP2C19 polymorphism, C-reactive protein, soluble P-selectin, CD40L, interleukin-6, PAI-1 levels, and von Willebrand factor activity were analyzed. RESULTS: The incidence (light transmission aggregometry <50%) of prestent HRPR was 16%. By univariate regression, body mass index (BMI; p = 0.02), total cholesterol (p = 0.01), low-density lipoproteins (p = 0.004), CYP2C19*2 allele carriage (p = 0.006), soluble P-selectin (p = 0.009), and von Willebrand factor (p = 0.04) were linked to future HRPR. However, multivariate regression analysis suggested that only BMI and P-selectin were independent predictors of HRPR. CONCLUSIONS: Platelet reactivity before elective stenting is associated with numerous biomarkers; however, only BMI and soluble P-selectin were independent predictors of future HRPR during maintenance-phase DAPT. This may be important for future tailored antiplatelet strategies in patients with metabolic syndrome and diabetics.

ACE phenotyping in human heart.

AIMS: Angiotensin-converting enzyme (ACE), which metabolizes many peptides and plays a key role in blood pressure regulation and vascular remodeling, is expressed as a type-1 membrane glycoprotein on the surface of different cells, including endothelial cells of the heart. We hypothesized that the local conformation and, therefore, the properties of heart ACE could differ from lung ACE due to different microenvironment in these organs. METHODS AND RESULTS: We performed ACE phenotyping (ACE levels, conformation and kinetic characteristics) in the human heart and compared it with that in the lung. ACE activity in heart tissues was 10-15 lower than that in lung. Various ACE effectors, LMW endogenous ACE inhibitors and HMW ACE-binding partners, were shown to be present in both heart and lung tissues. "Conformational fingerprint" of heart ACE (i.e., the pattern of 17 mAbs binding to different epitopes on the ACE surface) significantly differed from that of lung ACE, which reflects differences in the local conformations of these ACEs, likely controlled by different ACE glycosylation in these organs. Substrate specificity and pH-optima of the heart and lung ACEs also differed. Moreover, even within heart the apparent ACE activities, the local ACE conformations, and the content of ACE inhibitors differ in atria and ventricles. CONCLUSIONS: Significant differences in the local conformations and kinetic properties of heart and lung ACEs demonstrate tissue specificity of ACE and provide a structural base for the development of mAbs able to distinguish heart and lung ACEs as a potential blood test for predicting atrial fibrillation risk.

Independent Predictors of Major Adverse Events following Coronary Stenting over 28 Months of Follow-Up.

BACKGROUND: Despite recent advances in stent design and constantly improving protective pharmacological strategies, complications and adverse events following percutaneous coronary interventions (PCI) are still major factors influencing morbidity and mortality. Therefore, predicting secondary vascular occlusions represents an unmet medical need. OBJECTIVE: The aim of our study was to triage clinical and laboratory predictors of major adverse clinical events (MACE) following coronary stenting. METHODS: This was a prospective, case-controlled, single-center study, which included 94 consecutive patients with documented coronary disease who underwent PCI with drug-eluting stent (DES) implantation. All patients received dual antiplatelet therapy with aspirin and clopidogrel. Numerous clinical characteristics and laboratory biomarkers were assessed before stenting and were correlated with poststenting MACE over the mean follow-up of 28 months. MACE included death, nonfatal myocardial infarction, target vessel revascularisation, stroke, stent thrombosis, angina recurrence and instent restenosis. RESULTS: Twenty-three patients experienced MACE. Independent MACE predictors after PCI with DES implantation were antecedent diabetes mellitus (RR = 0.45; 95% CI 0.20-0.97; p = 0.045), prior thrombolytic therapy (RR = 0.42; 95% CI 0.27-0.83; p = 0.039), baseline plasminogen activator inhibitor -1 (PAI-1; p = 0.008) and plasma von Willebrand factor (vWF) activity (p = 0.007). Other clinical characteristics and laboratory indices showed no correlation with MACE. CONCLUSIONS: Background diabetes mellitus, prior thrombolytic therapy, PAI-1 and vWF prestenting activity may be useful for MACE prediction over 28 months of follow-up.

Clopidogrel response variability: impact of genetic polymorphism and platelet biomarkers for predicting adverse outcomes poststenting.

The aim of this study was to triage platelet reactivity and adverse vascular outcomes after dual antiplatelet therapy due to percutaneous coronary intervention (PCI) dependent on CYP2C19*2 and CYP2C19*3 genotypes in patients with coronary artery disease. Fifty-five patients with coronary artery disease were studied serially pre-PCI and post-PCI. Platelet reactivity was assessed by conventional light transmission aggregometry, VerifyNow Analyzer, and thromboelastography with platelet mapping. Genetic testing was performed with allele-specific real-time polymerase chain reaction. Adverse events included vascular death, acute myocardial infarction, repeated PCI, definite stent thrombosis, and angina recurrence. The common genotype (GG) was found in 39 patients, heterozygous polymorphism CYP2C19 (GA) G681A allele was detected in 14 patients, and the rare homozygous polymorphism CYP2C19 (AA) G681A allele was exhibited in 2 patients. There were no CYP2C19*3 (Trp212Ter) carriers among index patients. The platelet reactivity was higher in patients with heterozygous and homozygous carriers compared with GG genotype. The largest differences were observed among GG, GA, and AA genotypes, which correlated with the average values of platelet aggregation (P = 0.02). There was a significant link between adverse events and high platelet reactivity assessed by light transmission aggregometry (P = 0.002). We found a trend between different genotype and VerifyNow readings (P = 0.057); moreover, their cumulative impact on adverse events was significant (P = 0.041). Platelet reactivity is higher in patients with heterozygous and homozygous carriers of CYP2C19*2 versus common genotype and may predict an increased risk of clopidogrel response variability and/or experiencing adverse cardiac events.