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The Journal of Chemical Physics Mar 2023Pressure-induced perturbation of a protein structure leading to its folding-unfolding mechanism is an important yet not fully understood phenomenon. The key point here...
Correlation between protein conformations and water structure and thermodynamics at high pressure: A molecular dynamics study of the Bovine Pancreatic Trypsin Inhibitor (BPTI) protein.
Pressure-induced perturbation of a protein structure leading to its folding-unfolding mechanism is an important yet not fully understood phenomenon. The key point here is the role of water and its coupling with protein conformations as a function of pressure. In the current work, using extensive molecular dynamics simulation at 298 K, we systematically examine the coupling between protein conformations and water structures of pressures of 0.001, 5, 10, 15, 20 kbar, starting from (partially) unfolded structures of the protein Bovine Pancreatic Trypsin Inhibitor (BPTI). We also calculate localized thermodynamics at those pressures as a function of protein-water distance. Our findings show that both protein-specific and generic effects of pressure are operating. In particular, we found that (1) the amount of increase in water density near the protein depends on the protein structural heterogeneity; (2) the intra-protein hydrogen bond decreases with pressure, while the water-water hydrogen bond per water in the first solvation shell (FSS) increases; protein-water hydrogen bonds also found to increase with pressure, (3) with pressure hydrogen bonds of waters in the FSS getting twisted; and (4) water's tetrahedrality in the FSS decreases with pressure, but it is dependent on the local environment. Thermodynamically, at higher pressure, the structural perturbation of BPTI is due to the pressure-volume work, while the entropy decreases with the increase of pressure due to the higher translational and rotational rigidity of waters in the FSS. The local and subtle effects of pressure, found in this work, are likely to be typical of pressure-induced protein structure perturbation.
Topics: Animals; Cattle; Aprotinin; Water; Molecular Dynamics Simulation; Protein Conformation; Thermodynamics
PubMed: 36889972
DOI: 10.1063/5.0124837 -
Advances in Therapy Apr 2023The European Medicines Agency restored aprotinin (APR) use for preventing blood loss in patients undergoing isolated coronary artery bypass graft (iCABG) in 2016 but...
INTRODUCTION
The European Medicines Agency restored aprotinin (APR) use for preventing blood loss in patients undergoing isolated coronary artery bypass graft (iCABG) in 2016 but requested the collection of patient and surgery data in a registry (NAPaR). The aim of this analysis was to evaluate the impact of APR reintroduction in France on the main hospital costs (operating room, transfusion and intensive unit stay) compared to the current use of tranexamic acid (TXA), which was the only antifibrinolytic available before APR reinstatement.
METHODS
A multicenter before-after post-hoc analysis to compare APR and TXA was carried out in four French university hospitals. APR use followed the ARCOTHOVA (French Association of Cardiothoracic and Vascular Anesthetists) protocol, which had framed three main indications in 2018. Data from 236 APR patients were retrieved from the NAPaR (N = 874); 223 TXA patients were retrospectively retrieved from each center database and matched to APR patients upon indication classes. Budget impact was evaluated using both direct costs associated with antifibrinolytics and transfusion products (within the first 48 h) and other costs such as surgery duration and ICU stay.
RESULTS
The 459 collected patients were distributed as: 17% on-label; 83% off-label. Mean cost per patient until ICU discharge tended to be lower in the APR group versus the TXA group, which resulted in an estimated gross saving of €3136 per patient. These savings concerned operating room and transfusion costs but were mainly driven by reduced ICU stays. When extrapolated to the whole French NAPaR population, the total savings of the therapeutic switch was estimated at around €3 million.
CONCLUSION
The budget impact projected that using APR according to ARCOTHOVA protocol resulted in decreased requirement for transfusion and complications related to surgery. Both were associated with substantial cost savings from the hospital's perspective compared with exclusive use of TXA.
Topics: Humans; Aprotinin; Blood Loss, Surgical; Retrospective Studies; Cardiac Surgical Procedures; Antifibrinolytic Agents; Tranexamic Acid; Costs and Cost Analysis
PubMed: 36867329
DOI: 10.1007/s12325-023-02464-7 -
Medicine Mar 2023Significant blood loss is still one of the most frequent issues in spinal surgery. There were different hemostatic methods to prevent blood loss during spinal surgery.... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Significant blood loss is still one of the most frequent issues in spinal surgery. There were different hemostatic methods to prevent blood loss during spinal surgery. However, the optimal hemostatic therapy for spinal surgery is controversial. The purpose of this study was to assess the efficacy and safety of different hemostatic therapies in spinal surgery.
METHODS
Two independent reviewers conducted electronic literature searches in 3 electronic databases (PubMed, Embase, and Cochrane library database) as well as a manual search to identify eligible clinical studies from inception to Nov 2022. Studies that including different hemostatic therapy (tranexamic acid [TXA], epsilon-acetyl aminocaproic acid [EACA], and aprotinin [AP]) for spinal surgery were included. The Bayesian network meta-analysis was performed with a random effects model. The surface under the cumulative ranking curve (SUCRA) analysis was performed to determine the ranking order. All analyses were performed by R software and Stata software. P value less than .05 was identified as statistically significant.
RESULTS
Finally, a total of 34 randomized controlled trials met the inclusion criteria and finally included in this network meta-analysis. The SUCRA shows that TXA ranked first (SUCRA, 88.4%), AP ranked second (SUCRA, 71.6%), EACA ranked third (SUCRA, 39.9%), and placebo ranked the last (SUCRA, 0.3%) as for total blood loss. The SUCRA shows that TXA ranked first (SUCRA, 97.7%), AP ranked second (SUCRA, 55.8%), EACA ranked third (SUCRA, 46.2%), and placebo ranked the last (SUCRA, 0.2%) for need for transfusion.
CONCLUSIONS
TXA appears optimal in the reduction of perioperative bleeding and blood transfusion during spinal surgery. However, considering the limitations in this study, more large-scale, well-designed randomized controlled trials are needed to confirm these findings.
Topics: Humans; Hemostatics; Bayes Theorem; Network Meta-Analysis; Tranexamic Acid; Aminocaproic Acid
PubMed: 36862901
DOI: 10.1097/MD.0000000000032923 -
Regenerative Biomaterials 2023Inflammation manipulation and extracellular matrix (ECM) remodeling for healthy tissue regeneration are critical requirements for tissue engineering scaffolds. To this...
Inflammation manipulation and extracellular matrix (ECM) remodeling for healthy tissue regeneration are critical requirements for tissue engineering scaffolds. To this end, the bioactive polycaprolactone (PCL)-based scaffolds are fabricated to release aprotinin and thymosin β4 (Tβ4) in a programmable manner. The core part of the fiber is composed of hyaluronic acid and Tβ4, and the shell is PCL, which is further coated with heparin/gelatin/aprotinin to enhance biocompatibility. The assay demonstrates that the controlled release of aprotinin prevents initial excessive inflammation. The subsequent release of Tβ4 after 3 days induces the transition of macrophages from M1 into M2 polarization. The manipulation of inflammatory response further controls the expression of transforming growth factor-β and fibroblast activation, which oversee the quantity and quality of ECM remodeling. In addition, the gradual degradation of the scaffold allows cells to proliferate within the platform. implant evaluation convinces that PCL-based scaffolds possess the high capability to control the inflammatory response and restore the ECM to normal conditions. Hence, our work paves a new way to develop tissue engineering scaffolds for inflammation manipulation and ECM remodeling with peptide-mediated reactions.
PubMed: 36852398
DOI: 10.1093/rb/rbad010 -
The Cochrane Database of Systematic... Feb 2023Vascular surgery may be followed by internal bleeding due to inadequate surgical haemostasis, abnormal clotting, or surgical complications. Bleeding ranges from minor,... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Vascular surgery may be followed by internal bleeding due to inadequate surgical haemostasis, abnormal clotting, or surgical complications. Bleeding ranges from minor, with no transfusion requirement, to massive, requiring multiple blood product transfusions. There are a number of drugs, given systemically or applied locally, which may reduce the need for blood transfusion.
OBJECTIVES
To assess the effectiveness and safety of anti-fibrinolytic and haemostatic drugs and agents in reducing bleeding and the need for blood transfusion in people undergoing major vascular surgery or vascular procedures with a risk of moderate or severe (> 500 mL) blood loss.
SEARCH METHODS
We searched: Cochrane Central Register of Controlled Trials; MEDLINE; Embase; CINAHL, and Transfusion Evidence Library. We also searched the WHO ICTRP and ClinicalTrials.gov trial registries for ongoing and unpublished trials. Searches used a combination of MeSH and free text terms from database inception to 31 March 2022, without restriction on language or publication status.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) in adults of drug treatments to reduce bleeding due to major vascular surgery or vascular procedures with a risk of moderate or severe blood loss, which used placebo, usual care or another drug regimen as control.
DATA COLLECTION AND ANALYSIS
We used standard Cochrane methods. Our primary outcomes were units of red cells transfused and all-cause mortality. Our secondary outcomes included risk of receiving an allogeneic blood product, risk of reoperation or repeat procedure due to bleeding, risk of a thromboembolic event, risk of a serious adverse event and length of hospital stay. We used GRADE to assess certainty of evidence.
MAIN RESULTS
We included 22 RCTs with 3393 participants analysed, of which one RCT with 69 participants was reported only in abstract form, with no usable data. Seven RCTs evaluated systemic drug treatments (three aprotinin, two desmopressin, two tranexamic acid) and 15 RCTs evaluated topical drug treatments (drug-containing bioabsorbable dressings or glues), including fibrin, thrombin, collagen, gelatin, synthetic sealants and one investigational new agent. Most trials were conducted in high-income countries and the majority of the trials only included participants undergoing elective surgery. We also identified two ongoing RCTs. We were unable to perform the planned network meta-analysis due to the sparse reporting of outcomes relevant to this review. Systemic drug treatments We identified seven trials of three systemic drugs: aprotinin, desmopressin and tranexamic acid, all with placebo controls. The trials of aprotinin and desmopressin were small with very low-certainty evidence for all of our outcomes. Tranexamic acid versus placebo was the systemic drug comparison with the largest number of participants (2 trials; 1460 participants), both at low risk of bias. The largest of these included a total of 9535 individuals undergoing a number of different higher risk surgeries and reported limited information on the vascular subgroup (1399 participants). Neither trial reported the number of units of red cells transfused per participant up to 30 days. Three outcomes were associated with very low-certainty evidence due to the very wide confidence intervals (CIs) resulting from small study sizes and low number of events. These were: all-cause mortality up to 30 days; number of participants requiring an allogeneic blood transfusion up to 30 days; and risk of requiring a repeat procedure or operation due to bleeding. Tranexamic acid may have no effect on the risk of thromboembolic events up to 30 days (risk ratio (RR) 1.10, 95% CI 0.88 to 1.36; 1 trial, 1360 participants; low-certainty evidence due to imprecision). There is one large ongoing trial (8320 participants) comparing tranexamic acid versus placebo in people undergoing non-cardiac surgery who are at high risk of requiring a red cell transfusion. This aims to complete recruitment in April 2023. This trial has primary outcomes of proportion of participants transfused with red blood cells and incidence of venous thromboembolism (DVT or PE). Topical drug treatments Most trials of topical drug treatments were at high risk of bias due to their open-label design (compared with usual care, or liquids were compared with sponges). All of the trials were small, most were very small, and few reported clinically relevant outcomes in the postoperative period. Fibrin sealant versus usual care was the topical drug comparison with the largest number of participants (5 trials, 784 participants). The five trials that compared fibrin sealant with usual care were all at high risk of bias, due to the open-label trial design with no measures put in place to minimise reporting bias. All of the trials were funded by pharmaceutical companies. None of the five trials reported the number of red cells transfused per participant up to 30 days or the number of participants requiring an allogeneic blood transfusion up to 30 days. The other three outcomes were associated with very low-certainty evidence with wide confidence intervals due to small sample sizes and the low number of events, these were: all-cause mortality up to 30 days; risk of requiring a repeat procedure due to bleeding; and risk of thromboembolic disease up to 30 days. We identified one large trial (500 participants) comparing fibrin sealant versus usual care in participants undergoing abdominal aortic aneurysm repair, which has not yet started recruitment. This trial lists death due to arterial disease and reintervention rates as primary outcomes.
AUTHORS' CONCLUSIONS
Because of a lack of data, we are uncertain whether any systemic or topical treatments used to reduce bleeding due to major vascular surgery have an effect on: all-cause mortality up to 30 days; risk of requiring a repeat procedure or operation due to bleeding; number of red cells transfused per participant up to 30 days or the number of participants requiring an allogeneic blood transfusion up to 30 days. There may be no effect of tranexamic acid on the risk of thromboembolic events up to 30 days, this is important as there has been concern that this risk may be increased. Trials with sample size targets of thousands of participants and clinically relevant outcomes are needed, and we look forward to seeing the results of the ongoing trials in the future.
Topics: Adult; Humans; Aprotinin; Blood Transfusion; Deamino Arginine Vasopressin; Fibrin Tissue Adhesive; Hemorrhage; Network Meta-Analysis; Tranexamic Acid
PubMed: 36800489
DOI: 10.1002/14651858.CD013649.pub2 -
Journal of the American Chemical Society Jan 2023Peptides are steadily gaining importance as pharmaceutical targets, and efficient, green methods for their preparation are critically needed. A key deficiency in the...
Peptides are steadily gaining importance as pharmaceutical targets, and efficient, green methods for their preparation are critically needed. A key deficiency in the synthetic toolbox is the lack of an industrially viable peptide desulfurization method. Without this tool, the powerful native chemical ligation reaction typically used to assemble polypeptides and proteins remains out of reach for industrial preparation of drug targets. Current desulfurization methods require very large excesses of phosphine reagents and thiol additives or low-abundance metal catalysts. Here, we report a phosphine-only photodesulfurization (POP) using near-UV light that is clean, high-yielding, and requires as little as 1.2 equiv phosphine. The user-friendly reaction gives complete control to the chemist, allowing solvent and reagent selection based on starting material and phosphine solubility. It can be conducted in a range of solvents, including water or buffers, on protected or unprotected peptides, in low or high dilution and on gram scale. Oxidation-prone amino acids, π-bonds, aromatic rings, thio-aminal linkages, thioesters, and glycans are all stable to the POP reaction. We highlight the utility of this approach for desulfurization of industrially relevant targets including cyclic peptides and glucagon-like peptide 1 (GLP-1(7-36)). The method is also compatible with NCL buffer, and we highlight the robustness of the approach through the one-pot disulfide reduction/multidesulfurization of linaclotide, aprotinin, and wheat protein.
Topics: Sulfhydryl Compounds; Ultraviolet Rays; Peptides; Proteins
PubMed: 36602440
DOI: 10.1021/jacs.2c10625 -
Surgical Neurology International 2022Data exist of the benefits of antifibrinolytics such as tranexamic acid (TXA) in general spine surgery. However, there are limited data of its use in oncological spine... (Review)
Review
BACKGROUND
Data exist of the benefits of antifibrinolytics such as tranexamic acid (TXA) in general spine surgery. However, there are limited data of its use in oncological spine patients.
METHODS
A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Cochrane, OVID, and Embase databases were searched. Search terms: ", "," "," "," "," and "." Included studies were full text publications written in English with patients treated with either agent or who had surgery for oncological spine disease (OSD).
RESULTS
Seven hundred results were reviewed form the different databases, seven were selected. A total of 408 patients underwent spine surgery for OSD and received antifibrinolytics. There was a male predominance (55.2%) and mean age ranged from 43 to 62 years. The most common tumor operated was metastatic renal cancer, followed by breast and lung. Most studies administered TXA as a bolus followed by an infusion during surgery. Median blood loss was of 667 mL (253.3-1480 mL). Patients with TXA required 1-2 units less of transfusion and had 56-63 mL less of postoperative drainage versus no TXA. The median incidence of deep venous thrombosis (DVT) was 2.95% (0-7.9%) and for pulmonary embolism (PE) was 4.25% (0-14.3%). The use of TXA reduced intraoperative blood loss, transfusions and reduced postoperative surgical drainage output compared to no TXA use in patients with OSD.
CONCLUSION
In this review, we found that TXA may diminish intraoperative blood loss, the need for transfusion and postoperative drainage from surgical drains when used in OSD without major increase in rates of DVT or PE.
PubMed: 36600747
DOI: 10.25259/SNI_837_2022 -
Hormone and Metabolic Research =... Jan 2023Bleeding is a major complication in coronary artery bypass graft surgery. Antifibrinolytic agents like serine protease inhibitor aprotinin can decrease postoperative...
Bleeding is a major complication in coronary artery bypass graft surgery. Antifibrinolytic agents like serine protease inhibitor aprotinin can decrease postoperative bleeding and complications of cardiac surgery. However, the effects of aprotinin on vascular function are not completely elucidated. We compared the ex vivo vascular function of left internal mammary arteries from patients undergoing coronary artery bypass graft surgery with and without intraoperative application of aprotinin using a Mulvany Myograph. Human internal mammary arteries were treated with aprotinin ex vivo and tested for changes in vascular function. We analyzed the impact of aprotinin on vascular function in rat aortic rings. Finally, impact of aprotinin on expression and activity of endothelial nitric oxide synthase was tested in human endothelial cells. Intraoperative application of aprotinin did not impair ex vivo vascular function of internal mammary arteries of patients undergoing coronary artery bypass graft surgery. Endothelium-dependent and -independent relaxations were not different in patients with or without aprotinin after nitric oxide synthase blockade. A maximum vasorelaxation of 94.5%±11.4vs. 96.1%±5.5% indicated a similar vascular smooth muscle function in both patient groups (n=13 each). Long-term application of aprotinin under physiological condition preserved vascular function of the rat aorta. In vitro application of increasing concentrations of aprotinin on human endothelial cells resulted in a similar expression and activity of endothelial nitric oxide synthase. In conclusion, intraoperative and ex vivo application of aprotinin does not impair the endothelial function in human internal mammary arteries and experimental models.
Topics: Humans; Rats; Animals; Aprotinin; Nitric Oxide Synthase Type III; Endothelial Cells; Coronary Artery Bypass; Serine Proteinase Inhibitors
PubMed: 36599358
DOI: 10.1055/a-1984-0255 -
Microcirculation (New York, N.Y. : 1994) Jan 2023Post-hepatectomy liver failure (PHLF) is the main limitation of extended liver resection. The molecular mechanism and the role of leukocytes in the development of PHLF...
OBJECTIVE
Post-hepatectomy liver failure (PHLF) is the main limitation of extended liver resection. The molecular mechanism and the role of leukocytes in the development of PHLF remain to be unveiled. We aimed to address the impact of serine proteases (SPs) on the acute phase after liver resection by intravitally analyzing leukocyte recruitment and changes in hemodynamics and microcirculation of the liver.
METHODS
C57BL/6 mice undergoing 60% partial hepatectomy were treated with aprotinin (broad-spectrum SP inhibitor), tranexamic acid (plasmin inhibitor), or vehicle. Sham-operated animals served as controls. In vivo fluorescence microscopy was used to quantify leukocyte-endothelial interactions immediately after, as well as 120 min after partial hepatectomy in postsinusoidal venules, along with measurement of sinusoidal perfusion rate and postsinusoidal shear rate. Recruitment of leukocytes, neutrophils, T cells, and parameters of liver injury were assessed in tissue/blood samples.
RESULTS
Leukocyte recruitment, sinusoidal perfusion failure rate, and shear rate were significantly increased in mice after 60% partial hepatectomy compared to sham-operated animals. The inhibition of SPs or plasmin significantly attenuated leukocyte recruitment and improved the perfusion rate in the remnant liver. ICAM-1 expression and neutrophil recruitment significantly increased after 60% partial hepatectomy and were strongly reduced by plasmin inhibition.
CONCLUSIONS
Endothelial activation and leukocyte recruitment in the liver in response to the increment of sinusoidal shear rate were hallmarks in the acute phase after liver resection. SPs mediated leukocyte recruitment and contributed to the impairment of sinusoidal perfusion in an ICAM-1-dependent manner in the acute phase after liver resection.
Topics: Mice; Animals; Hepatectomy; Intercellular Adhesion Molecule-1; Serine Proteases; Fibrinolysin; Mice, Inbred C57BL; Liver; Leukocytes; Microcirculation
PubMed: 36577737
DOI: 10.1111/micc.12796 -
International Journal of Molecular... Nov 2022Characterization of the hydrated state of a protein is crucial for understanding its structural stability and function. In the present study, we have investigated the 3D...
Characterization of the hydrated state of a protein is crucial for understanding its structural stability and function. In the present study, we have investigated the 3D hydration structure of the protein BPTI (bovine pancreatic trypsin inhibitor) by molecular dynamics (MD) and the integral equation method in the three-dimensional reference interaction site model (3D-RISM) approach. Both methods have found a well-defined hydration layer around the protein and revealed the localization of BPTI buried water molecules corresponding to the X-ray crystallography data. Moreover, under 3D-RISM calculations, the obtained positions of waters bound firmly to the BPTI sites are in reasonable agreement with the experimental results mentioned above for the BPTI crystal form. The analysis of the 3D hydration structure (thickness of hydration shell and hydration numbers) was performed for the entire protein and its polar and non-polar parts using various cut-off distances taken from the literature as well as by a straightforward procedure proposed here for determining the thickness of the hydration layer. Using the thickness of the hydration shell from this procedure allows for calculating the total hydration number of biomolecules properly under both methods. Following this approach, we have obtained the thickness of the BPTI hydration layer of 3.6 Å with 369 water molecules in the case of MD simulation and 3.9 Å with 333 water molecules in the case of the 3D-RISM approach. The above procedure was also applied for a more detailed description of the BPTI hydration structure near the polar charged and uncharged radicals as well as non-polar radicals. The results presented for the BPTI as an example bring new knowledge to the understanding of protein hydration.
Topics: Cattle; Animals; Aprotinin; Proteins; Crystallography, X-Ray; Water; Molecular Dynamics Simulation; Protein Conformation; Trypsin
PubMed: 36499117
DOI: 10.3390/ijms232314785