Effect of Short PSG Peptides on Inflammatory Markers in Allogeneic Bone Marrow Cell Transplantation in Wistar Rats.

Short linear peptide fragments of placental trophoblastic ß1-glycoprotein (PSG) (YECE, YQCE, YVCS, and YACS) were studied in the context of their immunomodulatory effects at the level of inflammatory markers. The original host-versus-graft model was used in male Wistar rats without prior conditioning of recipient bone marrow. A composition of PSG peptide fragments was injected to animals after allogeneic transplantation of bone marrow cells in a dynamic experiment, inflammatory markers α1-acid glycoprotein (AGP, orosomucoid), α2-macroglobulin (α2M) were assayed by ELISA, and biochemical parameters (total protein, glucose, creatinine, and urea) were measured. The levels of α2M and AGP increased in response to allotransplantation, whereas administration of PSG peptides normalized serum α2M levels by the end of the experiment. The decrease in α2M level coincided with the independent effect of PSG peptide administration. The levels of total protein, glucose, creatinine, and urea in rat serum after allotransplantation were reduced throughout the experiment. Administration of PSG peptides contributed to normalization of serum total protein, creatinine, and urea levels by the end of the experiment. Administration of PSG peptides after allogeneic transplantation of bone marrow suspension contributed to normalization of the levels of α2M, total protein, creatinine, and urea, which can be interpreted as an anti-inflammatory effect of these peptides.

Value of 18F-FDG PET/CT combined with tumor markers ProGRP and NSE in diagnosis and differential diagnosis of stageⅠA small cell lung cancer / 中华核医学与分子影像杂志

Objective:To explore the value of 18F-FDG PET/CT combined with pro-gastrin-releasing peptide (ProGRP) and neuron-specific enolase (NSE) in diagnosis and differential diagnosis of stageⅠA small cell lung cancer (SCLC). Methods:From June 2017 to October 2021, 113 patients (75 males, 38 females; age 32-79 years) with stageⅠA lung cancer (70 with adenocarcinoma, 25 with squamous cell carcinoma, 18 with SCLC; patients with adenocarcinoma and squamous cell carcinoma were combined into non-SCLC (NSCLC) group) and 30 patients with benign pulmonary nodule (21 males, 9 females; age 37-77 years) from the Affiliated Qingdao Central Hospital of Qingdao University were retrospectively analyzed. All patients were examined by 18F-FDG PET/CT and serum tumor markers associated with lung cancer. Differences of the clinical, imaging and tumor markers data among different groups were analyzed by χ2 test, Fisher exact test and Kruskal-Wallis rank sum test. Independent risk factors were analyzed by logistic regression analysis and ROC curve analysis was used to analyze the value of different predictive factors in diagnosis and differential diagnosis of SCLC. Results:There were significant differences in SUV max, lobulation sign, spiculation sign, calcification, pleural traction sign, ProGRP, NSE and carcinoembryonic antigen (CEA) among SCLC, NSCLC and benign nodules groups ( H values: 14.06-20.54, χ2 values: 8.16-14.95, all P<0.05), in which lobulation sign of SCLC was more than that of benign nodules (12/18 vs 26.7%(8/30); χ2=7.41, P=0.007), spiculation sign (2/18 vs 51.6%(49/95); χ2=10.01, P=0.002) and pleural traction sign (1/18 vs 35.8%(34/95); χ2=6.47, P=0.011) were less than those of NSCLC, SUV max was higher than that of benign nodules (7.4(5.8, 9.0) vs 2.3(1.4, 5.1); H=51.82, P<0.001), ProGRP was higher than that of NSCLC and benign nodules (64.0(40.1, 84.8) vs 38.7(26.9, 47.6), 36.7(29.1, 40.5) ng/L; H values: 36.13, 43.96, P values: 0.002, 0.001) and NSE was higher than that of benign nodules (12.4(10.9, 14.5) vs 7.4(5.4, 11.8) μg/L; H=40.53, P=0.001). When differentiated SCLC from NSCLC, spiculation sign (odds ratio ( OR)=0.043, 95% CI: 0.004-0.450, P=0.009) and ProGRP ( OR=1.083, 95% CI: 1.035-1.133, P<0.001) were independent risk factors for SCLC, and the AUC of the two factors combination was 0.875, with the sensitivity and specificity of 14/18 and 84.2%(80/95). When differentiated SCLC from benign nodules, SUV max( OR=2.706, 95% CI: 1.099-6.662, P=0.030), ProGRP ( OR=1.165, 95% CI: 1.009-1.344, P=0.038) and NSE ( OR=1.639, 95% CI: 1.016-2.645, P=0.043) were independent risk factors for SCLC, and the AUC of the three factors combination was 0.985, with the sensitivity and specificity of 17/18 and 96.7%(29/30). Conclusion:18F-FDG PET/CT combined with tumor markers ProGRP and NSE is helpful to improve the diagnosis and differential diagnosis of stage ⅠA SCLC.

Quantification of Parathyroid Hormone and its Fragments in Serum by Liquid Chromatography-High-Resolution Mass Spectrometry.

Parathyroid hormone (PTH), an 84-amino acid peptide hormone, is a major regulator of calcium homeostasis. Quantification of PTH in serum is used clinically to investigate calcium imbalances and for monitoring osteodystrophy in patients with renal failure. In addition to intact PTH, several PTH fragments are found in circulation. Recent studies have shown that accurate quantification of PTH fragments may provide valuable clinical information in certain scenarios. In this chapter, a high-resolution mass spectrometry-based method for quantification of PTH (1-84) and its fragments is described. This method involves immunoaffinity capture of intact PTH and PTH-fragments followed by liquid chromatography-high-resolution mass spectrometry (LC-HRMS).

Circulating Levels of Endotrophin Are Prognostic for Long-Term Mortality after AKI.

Background: AKI involves a rapid decrease in kidney function that may be associated with structural damage. Early markers predicting AKI are emerging, but tools to assess patients' long-term health risks after AKI are still lacking. Endotrophin (ETP) is a bioactive molecule released during the formation of collagen type VI. We evaluated the potential of circulating ETP as a prognostic biomarker of adverse outcomes after AKI. Methods: We measured ETP in plasma samples collected 1 year after an episode of AKI, using the PRO-C6 ELISA in 801 patients (393 patients with AKI and 408 controls) from the prospective AKI Risk in Derby (ARID) study (ISRCTN25405995), who were then followed until year 3. Kidney disease progression was defined as ≥25% decline in eGFR combined with a decline in CKD stage. Results: ETP levels were significantly higher in the AKI group compared with controls (P<0.001). In the AKI group, ETP could discriminate patients with kidney disease progression at year 3 (AUC=0.67, P<0.01), whereas eGFR could not (AUC=0.51, P=0.57). In logistic regression including common risk factors, ETP was independently associated with kidney disease progression in patients with AKI (OR=1.10, P<0.01). ETP could discriminate survivors from nonsurvivors at year 3 (AUC=0.64, P<0.01). In a Cox proportional hazards regression for mortality after AKI that included common risk factors, only ETP (HR=1.05; P<0.001) and age (HR=1.06, P<0.01) were retained in the final model. Conclusions: Patients in the AKI group had higher levels of plasma ETP at year 1 as compared with those who had not had AKI. In the AKI group, ETP levels predict kidney disease progression and mortality. Because ETP is a profibrotic molecule, our findings may indicate that ETP identifies patients with active fibrogenesis after AKI, suggestive of long-term renal remodeling, which is associated with patient outcome.

Specific Peptide from the Novel W-Tau Isoform Inhibits Tau and Amyloid ß Peptide Aggregation In Vitro.

W-Tau, a new tau human-specific splicing isoform generated by intron retention, has been recently described. This isoform contains an 18-residue unique sequence corresponding to the translation of the retained region of intron 12. In this work, we have described that such 18-amino-acid peptide from the retained intron 12 can inhibit tau and ß amyloid peptides aggregation under in vitro conditions. This inhibitory function is also present in smaller fragments of the 18-residue peptide.

Digestive Enzyme Activity and Protein Degradation in Plasma of Heart Failure Patients.

INTRODUCTION: Heart failure is associated with degradation of cell functions and extracellular matrix proteins, but the trigger mechanisms are uncertain. Our recent evidence shows that active digestive enzymes can leak out of the small intestine into the systemic circulation and cause cell dysfunctions and organ failure. METHODS: Accordingly, we investigated in morning fasting plasma of heart failure (HF) patients the presence of pancreatic trypsin, a major enzyme responsible for digestion. RESULTS: Western analysis shows that trypsin in plasma is significantly elevated in HF compared to matched controls and their concentrations correlate with the cardiac dysfunction biomarker BNP and inflammatory biomarkers CRP and TNF-α. The plasma trypsin levels in HF are accompanied by elevated pancreatic lipase concentrations. The trypsin has a significantly elevated activity as determined by substrate cleavage. Mass spectrometry shows that the number of plasma proteins in the HF patients is similar to controls while the number of peptides was increased about 20% in HF patients. The peptides are derived from extracellular and intracellular protein sources and exhibit cleavage sites by trypsin as well as other degrading proteases (data are available via ProteomeXchange with identifier PXD026332).ConnclusionsThese results provide the first evidence that active digestive enzymes leak into the systemic circulation and may participate in myocardial cell dysfunctions and tissue destruction in HF patients. CONCLUSIONS: These results provide the first evidence that active digestive enzymes leak into the systemic circulation and may participate in myocardial cell dysfunctions and tissue destruction in HF patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12195-021-00693-w.

Investigating the antifibrotic potential of N-acetyl seryl-aspartyl-lysyl-proline sequence peptides.

N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is a physiological antifibrotic peptide that is hydrolysed by angiotensin I-converting enzyme (ACE). The beneficial antifibrotic effects of ACE inhibitors have been attributed, in part, to its inhibition of Ac-SDKP cleavage. There is indirect evidence that the SDK fragment of Ac-SDKP is the main component required for its antiproliferative action. However, the exact component of the physiological peptide that is responsible for its antifibrotic effect has yet to be determined. Ac-SDKP-derived analogues that are resistant to ACE degradation may provide a new avenue for fibrosis therapy. We tested the antifibrotic potential of various Ac-SDKP peptide sequences and an analogue resistant to ACE degradation in lung fibroblasts. We investigated the contribution and molecular mechanism of action of the amino acid residues in the Ac-SDKP sequence to its antifibrotic effects, and the effects of Ac-SDKP peptides in the prevention of collagen deposition in cells. The Ac-DKP fragment moderately inhibited endothelin-1 (ET-1) mediated transforming growth factor-ß (TGF- ß) expression, and could be slowly cleaved by ACE, revealing a different sequence requirement for the antifibrotic action of Ac-SDKP. The Ac-SDψKP analogue (where the peptide bond between the aspartate and lysine is reduced) inhibited TGF-ß/small mother against decapentaplegic (Smad)-3 signalling and collagen deposition. The Ac-SDKP peptide, in combination with ACEi, demonstrated a greater inhibition of hydroxyproline as compared to Ac-SDKP alone.

A tale of two tails: Self-assembling properties of A- and B-chain parts of insulin's highly amyloidogenic H-fragment.

Due to the spontaneous transition of native insulin into therapeutically inactive amyloid, prolonged storage decreases effectiveness of the hormone in treatment of diabetes. Various regions of the amino acid sequence have been implicated in insulin aggregation. Here, we focus on smaller fragments of the highly amyloidogenic H-peptide comprising disulfide-bonded N-terminal sections of insulin's A-chain (13 residues) and B-chain (11 residues). Aggregation patterns of N-terminal fragments of A-chain (ACC1-13, ACC1-11, ACC6-13, ACC6-11, all retaining Cys6A-Cys11A disulfide bond) and B-chain (B1-11(7A)) are examined at acidic and neutral pH. ACC1-11 is the smallest fragment found to be amyloidogenic at either pH; removal of the N-terminal GIVEQ section renders this fragment entirely non-amyloidogenic. The self-assembling properties of ACC1-11 contrast with aggregation-resistant behavior of B1-11(7A) and its disulfide-linked homodimer, (B1-11)2 aggregating only at neutral pH. Fibrillar ACC1-11 is similar to insulin amyloid in terms of morphology and infrared features. Secondary nucleation is likely to account for the detected shortening of insulin aggregation lag phase at neutral pH upon cross-seeding with pre-formed fibrils of ACC1-11 or (B1-11)2. An aggregation-enhancing effect of monomeric ACC1-11 on co-dissolved native insulin is also observed. Our findings are discussed in the context of mechanisms of insulin aggregation.

Exploring amyloid oligomers with peptide model systems.

The assembly of amyloidogenic peptides and proteins, such as the ß-amyloid peptide, α-synuclein, huntingtin, tau, and islet amyloid polypeptide, into amyloid fibrils and oligomers is directly linked to amyloid diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases, frontotemporal dementias, and type II diabetes. Although amyloid oligomers have emerged as especially important in amyloid diseases, high-resolution structures of the oligomers formed by full-length amyloidogenic peptides and proteins have remained elusive. Investigations of oligomers assembled from fragments or stabilized ß-hairpin segments of amyloidogenic peptides and proteins have allowed investigators to illuminate some of the structural, biophysical, and biological properties of amyloid oligomers. Here, we summarize recent advances in the application of these peptide model systems to investigate and understand the structures, biological properties, and biophysical properties of amyloid oligomers.

A Retrospective Study of Admission NT-proBNP Levels as a Predictor of Readmission Rate, Length of Stay and Mortality.

Introduction: Serum levels of pro-B-type natriuretic peptide (BNP) and N-terminal (NT) proBNP are measured at admission to assess the likelihood of acutely decompensated heart failure (ADHF). Elevated NT-proBNP levels on initial presentation are a reliable marker of ADHF. However, the prognostic significance of NT-proBNP levels measured on admission remains unknown. With a better understanding of how admitting NT-proBNP levels impacts readmission rates, length of stay and mortality, future prospective studies with specific interventions can be developed to reduce all-cause readmissions, shorten length of stay and reduce mortality. Methods: In this retrospective study, we evaluated heart failure with reduced ejection fraction (HFrEF) admissions from 2017-2018 with a focus on 30-, 60- and 90-day all-cause readmissions, length of stay (LOS) and in-hospital mortality rate that are predicted by NT-proBNP levels measured on admission. Using the HCA Healthcare Enterprise Data Warehouse, adult patients age 18 to 75 were selected using admission ICD-10 codes for HFrEF. Dialysis patients were excluded. Our search of 90 hospitals yielded 21,445 patients who were stratified into quartiles depending on their admission NT-proBNP levels: group 1 (<1669 pg/ml), group 2 (1670-4274 pg/ml), group 3 (4275-10,499 pg/ml) and group 4 (>10,500 pg/ml). Results: Readmission Rates: The 60-day all-cause readmission was significantly (p = 0.047) higher in group 4 compared to group 1 (adjusted odds ratio (OR) = 1.116, p = 0.013) and group 2 (adjusted OR = 1.111, p = 0.014). The 90-day all cause readmission for group 4 was also significantly higher when compared to group 1 (adjusted OR = 1.105, p = 0.021).Length of Stay: Elevated NT-proBNP concentrations were associated with a significantly longer LOS (p <0.0005). Pairwise, comparisons and estimates for adjusted LOS showed a positive linear association between higher NT-proBNP groups and longer LOS.Mortality: Higher inpatient mortality rates were associated with elevated NT-proBNP levels. The mortality rate was 0.9% in group 1 compared to a 4.7% mortality rate in group 4. Adjusted OR for mortality increased with increasing levels of NT-proBNP. Conclusions: Based on the analysis, higher admitting NT-proBNP levels were associated with significantly higher 60-day all-cause readmission, longer LOS and increased mortality. These findings suggest that measuring NT-proBNP levels at admission may provide an indication of patient outcomes. Prospective studies with targeted strategies can be developed to reduce readmissions, shorten LOS and reduce mortality based on admission NT-proBNP levels.

Value of microalbuminuria in the diagnosis of heart failure with preserved ejection fraction.

OBJECTIVE: Elevated microalbuminuria (MAU) levels have been demonstrated in patients with heart failure with reduced ejection fraction (HFrEF). However, nothing is known about MAU levels in patients with heart failure with preserved ejection fraction (HFpEF). Therefore, the aim of our study was to explore the relationship between MAU levels and HFpEF. METHODS: The MAU and N­terminal B­type natriuretic peptide (NT-proBNP) concentrations were examined in 260 participants, including 160 patients with HFpEF and 100 control subjects without HF. Echocardiography was performed on all study participants. The patients with HFpEF were divided into class II, III, or IV according to the New York Heart Association (NYHA) classification. RESULTS: The MAU levels in the HFpEF group were significantly higher than those in the non-HF group (58.97 ± 89.84 vs. 19.56 ± 29.34, p > 0.05). However, there was no significant difference in the levels of MAU among NYHA class II-IV patients in the HFpEF group (p > 0.05). In Pearson linear correlation analysis, MAU levels in the HFpEF group were positively correlated with left atrial diameter (LAD; r = 0.344, p < 0.05), but negatively correlated with hemoglobin (r = - 0.233, p < 0.05). The area under the ROC curve (AUC) of MAU for the diagnosis of HFpEF was 0.83 (95% CI [0.76, 0.90], p < 0.05), the sensitivity was 72.50%, and the specificity was 82.0%. The AUC of NT-proBNP was 0.88 (95% CI [0.83, 0.94], p < 0.05), the sensitivity was 82%, and the specificity was 73.8%. The AUC of MAU combined with NT-proBNP was 0.91 (95% CI [0.86, 0.96], p < 0.05). CONCLUSION: Our results show that MAU can be used as a biomarker for the diagnosis of HFpEF. Combined detection of MAU with NT-proBNP has clinical value in improving the accuracy of diagnosis of HFpEF. However, there is no significant correlation between MAU levels and the severity of HFpEF.

Spatial Structure and Activity of Synthetic Fragments of Lynx1 and of Nicotinic Receptor Loop C Models.

Lynx1, membrane-bound protein co-localized with the nicotinic acetylcholine receptors (nAChRs) and regulates their function, is a three-finger protein (TFP) made of three ß-structural loops, similarly to snake venom α-neurotoxin TFPs. Since the central loop II of α-neurotoxins is involved in binding to nAChRs, we have recently synthesized the fragments of Lynx1 central loop, including those with the disulfide between Cys residues introduced at N- and C-termini, some of them inhibiting muscle-type nAChR similarly to the whole-size water-soluble Lynx1 (ws-Lynx1). Literature shows that the main fragment interacting with TFPs is the C-loop of both nAChRs and acetylcholine binding proteins (AChBPs) while some ligand-binding capacity is preserved by analogs of this loop, for example, by high-affinity peptide HAP. Here we analyzed the structural organization of these peptide models of ligands and receptors and its role in binding. Thus, fragments of Lynx1 loop II, loop C from the Lymnaea stagnalis AChBP and HAP were synthesized in linear and Cys-cyclized forms and structurally (CD and NMR) and functionally (radioligand assay on Torpedo nAChR) characterized. Connecting the C- and N-termini by disulfide in the ws-Lynx1 fragment stabilized its conformation which became similar to the loop II within the 1H-NMR structure of ws-Lynx1, the activity being higher than for starting linear fragment but lower than for peptide with free cysteines. Introduced disulfides did not considerably change the structure of HAP and of loop C fragments, the former preserving high affinity for α-bungarotoxin, while, surprisingly, no binding was detected with loop C and its analogs.

Peptide Extracts from Seven Medicinal Plants Discovered to Inhibit Oomycete Phytophthora infestans, a Causative Agent of Potato Late Blight Disease.

We report the inhibitory effect of peptide extracts obtained from seven medicinal plants against a causative agent of late blight disease Phytophthora infestans. We find that all the extracts possess inhibitory activity toward the zoospores output, zoosporangium germination, and the development of P. infestans on potato disc tubers at different quantitative levels. Based on the biological effects detected, an extract of common horsetail (Equisetum arvense) biomass is recognized as the most effective and is selected for further structural analysis. We perform a combination of amino acid analysis and MALDI-TOF mass spectrometry, which reveal the presence of Asn/Asp- and Gln/Glu-rich short peptides with molecular masses in the range of 500-900 Da and not exceeding 1500 Da as the maximum. Analytical anion-exchange HPLC is successfully applied for separation of the peptide extract from common horsetail (E. arvense). We collect nine dominant components that are combined in two groups with differences in retention times. The N-terminal amino acid sequence of the prevalent compounds after analytical ion-exchange HPLC allows us to identify them as peptide fragments of functionally active proteins associated with photosynthesis, aquatic transport, and chitin binding. The anti-oomycete effects may be associated with the conversion of ribulose-1,5-bisphosphate carboxylase/oxygenase to produce a number of biologically active anionic peptides with possible regulatory functions. These data inform our knowledge regarding biologically active peptide fragments; they are the components of programmed or induced proteolysis of plant proteins and can realize secondary antimicrobial functions.

Aluminium Binding to Modified Amyloid-ß Peptides: Implications for Alzheimer's Disease.

Aluminium (Al) is clearly neurotoxic and considerable evidence exists that Al may play a role in the aetiology or pathogenesis of Alzheimer's disease (AD). Nevertheless, the link between AD pathology and Al is still open to debate. Therefore, we investigated here the interaction of aluminium ions with two Aß peptide fragments and their analogues. First, we synthesised by the Fmoc/tBu solid-phase peptide synthesis (SPPS) strategy using an automated peptide synthesiser two new peptides starting from the Aß(1-16) native peptide fragment. For this purpose, the three histidine residues (H6, H13, and H14) of the Aß(1-16) peptide were replaced by three alanine and three serine residues to form the modified peptides Aß(1-16)A36,13,14 and Aß(1-16)S36,13,14 (primary structures: H-1DAEFRADSGYEVAAQK16-NH2 and H-1DAEFRSDSGYEVSSQK16-NH2). In addition, the Aß(9-16) peptide fragment (H-9GYEVHHQK16-NH2) and its glycine analogues, namely Aß(9-16)G110, (H-9GGEVHHQK16-NH2), Aß(9-16)G213,14 (H-9GYEVGGQK16-NH2), and Aß(9-16)G310,13,14 (H-9GGEVGGQK16-NH2), were manually synthesised in order to study Al binding to more specific amino acid residues. Both the peptides and the corresponding complexes with aluminium were comparatively investigated by mass spectrometry (MS), circular dichroism spectroscopy (CD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). Al-peptide molecular ions and Al-fragment ions were unambiguously identified in the MS and MS/MS spectra. AFM images showed dramatic changes in the film morphology of peptides upon Al binding. Our findings from the investigation of N-terminal 1-16 and even 9-16 normal and modified sequences of Aß peptides suggest that they have the capability to be involved in aluminium ion binding associated with AD.

Exposing the High Heterogeneity of Circulating Pro B-Type Natriuretic Peptide Fragments in Healthy Individuals and Heart Failure Patients.

BACKGROUND: The high molecular complexity of variably O-glycosylated and degraded pro B-type natriuretic peptide (proBNP) derived molecular forms challenges current immunoassays. Antibodies used show pronounced differences in cross-reactivities with these circulating fragments, which still need to be better characterized on a molecular level. To pave the way for advanced quantitative assays in the future, it is critical to fully understand these circulating forms. METHODS: Plasma samples were collected from 8 heart failure (HF) patients and 2 healthy controls. NT-proBNP and proBNP were purified by immunoprecipitation and analyzed by nano-flow liquid chromatography coupled to high-resolution mass spectrometry. Fragments formed during proteolysis in solution digestion were distinguished from naturally occurring peptides by using an 18O stable isotope labeling strategy. RESULTS: We detected 16 previously unknown circulating fragments of proBNP peptides (9 of which are located in the N-terminal and 7 in the C-terminal region), revealing a more advanced state of degradation than previously known. Two of these fragments are indicative of either unidentified processing modes or a far-reaching C-terminal degradation (or a combination thereof) of the precursor proBNP. CONCLUSIONS: Our results further restrict ideal target epitopes for immunoassay antibodies and expand the current thinking of diversity, degradation, and processing of proBNP, as well as the distribution of circulating forms.

Plasma Biomarkers to Predict Cardiovascular Outcome in Patients With Peripheral Artery Disease: A Systematic Review and Meta-Analysis.

OBJECTIVE: Patients with lower extremity peripheral artery disease (PAD) are at increased risk of major adverse cardiovascular events. Numerous plasma biomarkers have been investigated in lower extremity PAD, but none are used for clinical risk assessment. We aimed to provide a comprehensive overview of biomarker testing in PAD as a first step to improve risk stratification. Approach and Results: A systematic literature review in MEDLINE/PubMed, Cochrane, and Embase was performed, identifying all studies investigating plasma biomarkers in association with cardiovascular events and mortality in lower extremity PAD. Forty-seven studies comprising 21 473 PAD patients met our criteria and were included. Effect estimates were provided by the studies based on a minimum follow-up of 1 year. Meta-analyses were performed by pooling studies per biomarker for each end point. Patients with increased high-sensitivity CRP (C-reactive protein) levels had a relative risk of 1.86 (1.48-2.33) for major adverse cardiovascular events and a relative risk of 3.49 (2.35-5.19) for mortality. Increased fibrinogen and d-dimer levels were associated with an increased relative risk of mortality of 2.08 (1.46-2.97) and 2.22 (1.24-3.98), respectively. Additionally, patients with increased NT-proBNP (N-terminal pro-B-type natriuretic peptide) and high-sensitivity cTnT (cardiac troponin T) levels were at an even higher risk of mortality with relative risks of 4.50 (2.98-6.81) and 3.33 (2.70-4.10), respectively. CONCLUSIONS: This systematic review identifies promising biomarkers representing different pathophysiological processes implicated in lower extremity PAD, including high-sensitivity CRP, neutrophil-lymphocyte ratio, fibrinogen, d-dimer, NT-proBNP, and high-sensitivity cTnT. Clinical implementation should be preceded by a management study to test the utility of a combination of these markers for individual risk stratification. Ultimately, this may contribute to tailored treatment and increased effectiveness of current treatment strategies in PAD.

Top-Down Proteomics Applied to Human Cerebrospinal Fluid.

Cerebrospinal fluid (CSF) is the fluid of choice to study pathologies and disorders of the central nervous system (CNS). Its composition, especially its proteins and peptides, holds the promise that it may reflect the pathological state of an individual. Traditionally, proteins and peptides in CSF have been analyzed using bottom-up proteomics technologies in the search of high proteome coverage. However, the limited protein sequence coverage of this technology means that information regarding post-translational modifications (PTMs) and alternative splice variants is lost. As an alternative technology, top-down proteomics offers low to medium proteome coverage, but high protein coverage enabling almost a full characterization of the proteins' primary structure. This allows us to precisely identify distinct molecular forms of proteins (proteoforms) as well as naturally occurring bioactive peptide fragments, which could be of critical biological relevance and would otherwise remain undetected with a classical proteomics approach.Here, we describe various strategies including sample preparation protocols, off-line intact protein prefractionation, and LC-MS/MS methods together with data analysis pipelines to analyze cerebrospinal fluid (CSF) by top-down proteomics. However, there is not a unique or standardized method and the selection of the top-down strategy will depend on the exact goal of the study. Here, we describe various top-down proteomics methods that enable rapid protein characterization and may be an excellent companion analytical workflow in the search for new protein biomarkers in neurodegenerative diseases.

From Synthetic Fragments of Endogenous Three-Finger Proteins to Potential Drugs.

The proteins of the Ly6 family have a three-finger folding as snake venom α-neurotoxins, targeting nicotinic acetylcholine receptors (nAChRs), and some of them, like mammalian secreted Ly6/uPAR protein (SLURP1) and membrane-attached Ly-6/neurotoxin (Lynx1), also interact with distinct nAChR subtypes. We believed that synthetic fragments of these endogenous proteins might open new ways for drug design because nAChRs are well-known targets for developing analgesics and drugs against neurodegenerative diseases. Since interaction with nAChRs was earlier shown for synthetic fragments of the α-neurotoxin central loop II, we synthesized a 15-membered fragment of human Lynx1, its form with two Cys residues added at the N- and C-termini and forming a disulfide, as well as similar forms of human SLURP1, SLURP2, and of Drosophila sleepless protein (SSS). The IC50 values measured in competition with radioiodinated α-bungarotoxin for binding to the membrane-bound Torpedo californica nAChR were 4.9 and 7.4 µM for Lynx1 and SSS fragments, but over 300 µM for SLURP1 or SLURP2 fragments. The affinity of these compounds for the α7 nAChR in the rat pituitary tumor-derived cell line GH4C1 was different: 13.1 and 147 µM for SSS and Lynx1 fragments, respectively. In competition for the ligand-binding domain of the α9 nAChR subunit, SSS and Lynx1 fragments had IC50 values of about 40 µM, which correlates with the value found for the latter with the rat α9α10 nAChR expressed in the Xenopus oocytes. Thus, the activity of these synthetic peptides against muscle-type and α9α10 nAChRs indicates that they may be useful in design of novel myorelaxants and analgesics.

Radial versus femoral access in patients with acute coronary syndrome undergoing invasive management: A prespecified subgroup analysis from VALIDATE-SWEDEHEART.

AIMS: In the Bivalirudin versus Heparin in ST-Segment and Non-ST-Segment Elevation Myocardial Infarction in Patients on Modern Antiplatelet Therapy in the Swedish Web System for Enhancement and Development of Evidence-based Care in Heart Disease Evaluated according to Recommended Therapies Registry Trial (VALIDATE-SWEDEHEART), bivalirudin was not superior to unfractionated heparin in patients with acute coronary syndrome undergoing invasive management. We assessed whether the access site had an impact on the primary endpoint of death, myocardial infarction or major bleeding at 180 days and whether it interacted with bivalirudin/unfractionated heparin. METHODS AND RESULTS: A total of 6006 patients with acute coronary syndrome planned for percutaneous coronary intervention were randomised to either bivalirudin or unfractionated heparin. Arterial access was left to the operator discretion. Overall, 90.5% of patients underwent transradial access and 9.5% transfemoral access. Baseline risk was higher in transfemoral access. The unadjusted hazard ratio for the primary outcome was lower with transradial access (hazard ratio 0.53, 95% confidence interval 0.43-0.67, p<0.001) and remained lower after multivariable adjustment (hazard ratio 0.56, 95% confidence interval 0.52-0.84, p<0.001). Transradial access was associated with lower risk of death (hazard ratio 0.41, 95% confidence interval 0.28-0.60, p<0.001) and major bleeding (hazard ratio 0.57, 95% confidence interval 0.44-0.75, p<0.001). There was no interaction between treatment with bivalirudin and access site for the primary endpoint (p=0.976) or major bleeding (p=0.801). CONCLUSIONS: Transradial access was associated with lower risk of death, myocardial infarction or major bleeding at 180 days. Bivalirudin was not associated with less bleeding, irrespective of access site.

What is the role of peptide fragments of collagen I and IV in health and disease?

Collagen is the most abundant protein in mammalian systems; it can be found in organs such as bones, the liver, kidney, heart, teeth, and skin. Collagen provides the necessary structural framework for tissues in which it is found. However, if there are any alterations in the delicate balance of collagen types in the extracellular matrix (ECM), then problems arise. For example, increasing collagen I:III ratio would provide additional rigidity to tissue structure, whereas decreasing this ratio would provide elasticity and flexibility to the tissue. The proper function of tissues is reliant on this scale not tipping too far in either direction. Major players in the process of ECM remodeling, both normal and adverse, are the fibroblast cells via the secretion of collagen precursors and matrix metalloproteinases, with the latter responsible for ECM degradation. The collagen peptides created by the proteolytic cleavage of these collagen fibrils, while once thought to have an absence of function, have been shown over recent years to potentiate and regulate a variety of cellular processes acting through integrin receptors. Many collagen peptides have been identified from many different collagen types and have been shown to regulate processes such as cell proliferation, migration, apoptosis, and reduce angiogenesis. The collagen peptides of interest are those generated from the primary collagen type of tissue interstitial matrix, collagen type I, and the basement membrane, collagen type IV. Thus, this review looks to highlight some examples of unorthodox functional roles of collagen and its peptides in regulating physiological health and disease.