Specific Degradation Products Research Articles

Rapid biotransformation of STW 5 constituents by human gut microbiome from IBS- and non-IBS donors.

STW 5 is an herbal medicinal product with proven clinical efficacy in the treatment of functional gastrointestinal disorders, like functional dyspepsia and irritable bowel syndrome (IBS). The effects of STW 5 on fecal microbial communities and metabolite production effects have been studied in an experimental model with fecal samples from individuals with and without IBS. While only minor taxonomic disparities were noted between IBS- and non-IBS samples and upon treatment with STW 5, rapid metabolic turnover of STW 5 components into specific degradation products with reported anti-inflammatory, cytoprotective, or spasmolytic activities was observed, which may be relevant for the pharmacological activity of STW 5.

Islatravir Dimer: Crystal Form Dependence of a Radiation-Induced Degradation Product.

A rare example of crystal form-dependent, gamma radiation-induced degradation is presented. Islatravir is known to exist in several polymorphic forms, but only one of these forms shows the generation of a specific dimer degradation product under gamma irradiation. Extended gamma irradiation studies demonstrated that only one of the known crystalline forms shows an appreciable rate of dimer formation. Additionally, this dimer is not observed to form under other forced stress conditions. We present the structural elucidation of this dimer impurity and rationalize its form-dependent generation based on the analysis of the underlying crystal structure.

DypB peroxidase for aflatoxin removal: New insights into the toxin degradation process

Aflatoxin B1 (AFB1) is one of the most potent carcinogens and a widespread food and feed contaminant. As for other toxins, many efforts are devoted to find efficient and environmentally-friendly methods to degrade AFB1, such as enzymatic treatments, thus improving the safety of food and feed products. In this regard, the dye decolorizing peroxidase of type B (DypB) can efficiently degrade AFB1. The molecular mechanism, which is required to drive protein optimization in view of the usage of DypB as a mycotoxin reduction agent in large scale application, is unknown. Here, we focused on the role of four DypB residues in the degradation of AFB1 by alanine-scanning (residues 156, 215, 239 and 246), which were identified from biochemical assays to be kinetically relevant for the degradation. As a result of DypB degradation, AFB1 is converted into four products. Interestingly, the relative abundancy of these products depends on the replaced residues. Molecular dynamics simulations were used to investigate the role of these residues in the binding step between protein and manganese, a metal ion which is expected to be involved in the degradation process. We found that the size of the haem pocket as well as conformational changes in the protein structure could play a role in determining the kinetics of AFB1 removal and, consequently, guide the process towards specific degradation products.

The Effect of Biochar Addition on Thermal Stability and Decomposition Mechanism of Poly(butylene succinate) Bionanocomposites.

In the present study, poly(butylene succinate) (PBSu) and its bionanocomposites containing 1, 2.5, and 5 wt.% biochar (MSP700) were prepared via in situ melt polycondensation in order to investigate the thermal stability and decomposition mechanism of the materials. X-ray photoelectron spectroscopy (XPS) measurements were carried out to analyze the surface area of a biochar sample and PBSu/biochar nanocomposites. From XPS, it was found that only physical interactions were taking place between PBSu matrix and biochar nanoadditive. Thermal stability, decomposition kinetics, and the decomposition mechanism of the pristine PBSu and PBSu/biochar nanocomposites were thoroughly studied by thermogravimetric analysis (TGA) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). TGA thermograms depicted that all materials had high thermal stability, since their decomposition started at around 300 °C. However, results indicated a slight reduction in the thermal stability of the PBSu biochar nanocomposites because of the potential catalytic impact of biochar. Py-GC/MS analysis was employed to examine, in more detail, the thermal degradation mechanism of PBSu nanocomposites filled with biochar. From the decomposition products identified by Py-GC/MS after pyrolysis at 450 °C, it was found that the decomposition pathway of the PBSu/biochar nanocomposites took place mainly via β-hydrogen bond scission, which is similar to that which took place for neat PBSu. However, at higher biochar content (5 wt.%), some localized differences in the intensity of the peaks of some specific thermal degradation products could be recognized, indicating that α-hydrogen bond scission was also taking place. A study of the thermal stability and decomposition pathway of PBSu/biochar bionanocomposites is crucial to examine if the new materials fulfill the requirements for further investigation for mulch films in agriculture or in electronics as possible applications.

Identification of polystyrene nanoplastics from natural organic matter in complex environmental matrices by pyrolysis-gas chromatography-mass spectrometry.

Due to the flux of plastic debris entering the environment, it becomes urgent to document and monitor their degradation pathways at different scales. At the colloidal scale, the systematic hetero-association of nanoplastics with the natural organic matter complexifies the ability to detect plastic signatures in the particle collected in the various environments. The current techniques used for microplastics could not discriminate the polymers at the nanoscale from the natural macromolecules, as the plastic mass in the aggregate is within the same order. Only a few methods are available concerning nanoplastics identification in complex matrices, with the coupling of pyrolysis with gas chromatography and mass spectrometry (Py-GC-MS) as one of the most promising due to its mass-based detection. However, natural organic matter in environmental samples interferes with similar pyrolysis products. These interferences are even more critical for polystyrene polymers as this plastic presents no dominant pyrolysis markers, such as polypropylene, that could be identified at trace concentrations. Here, we investigate the ability to detect and quantify polystyrene nanoplastics in a rich phase of natural organic matter proposed based on the relative ratio of pyrolyzates. The use of specific degradation products (styrene dimer and styrene trimer) and the toluene/styrene ratio (RT/S) are explored for these two axes. While the size of the polystyrene nanoplastics biased the pyrolyzates of styrene dimer and trimer, the RT/S was correlated with the nanoplastics mass fraction in the presence of natural organic matter. An empirical model is proposed to evaluate the relative quantity of polystyrene nanoplastics in relevant environmental matrices. The model was applied to real contaminated soil by plastic debris and literature data to demonstrate its potential.

Determination of polyacrylamide based flocculants in sewage sludge by off-line thermochemolysis-GC–MS analysis

This study aimed to develop an offline thermochemolysis method for the determination of cationic polyacrylamide (cPAA) flocculants in environmental samples, using trimethylanilline hydroxide as a thermochemolytic agent. This method induces degradation of cPAA into defined substituted glutarimide derivates, as specific pyrolysis products. These pyrolysis products appeared in typical pattern of homologues allowing not only an unambiguous identification of the polymer but, more important, also a reliable pyrolysis based quantification in environmental concentration levels. Pyrolysis analysis were carried out on pure cPAA and spiked samples for method optimization, as well as on four sewage sludge samples from Germany as proof of applicability. All four specific degradation products were identified in three out of four sewage sludge samples indicating that the developed TMAH-thermochemolysis method is suitable for PAA detection in complex matrices and on environmentally relevant concentration levels. Nevertheless, experiments on sewage sludge samples revealed cPAA contamination in a concentration range between 29 and 76 μg/g. However, it has to be noted that the presence of all four specific degradation products has to be validated in order to have a doubtless cPAA confirmation in environmental samples.

Preparation of 3DG-SnO2 anode for electrochemical oxidation of 2,4,6-trichlorophenol: Theoretical calculation and degradation pathways

Novel three-dimensional graphene and SnO2 (3DG-SnO2) composite anode was prepared by a simple pressing process for electrochemical oxidation of 2,4,6-trichlorophenol (2,4,6-TCP). The 3DG-SnO2 material was studied by SEM, TEM, XRD and FTIR to characterize its morphology, crystal structure and functional group. The cyclic voltammetry and linear scan voltammetry were carried out to evaluate electrochemical performance of 3DG-SnO2 samples. The characterization results reveal that the SnO2 were homogeneously distributed in the 3DG, and the composite of 3DG greatly enhanced the oxygen evolution voltage and active sites of SnO2. Active species trapping experiments indicate that the •OH radicals was the most important oxidant species and the •OH generation rate at 3DG-SnO2 material was 2.60 times higher than that of bare SnO2 anode. Therefore, in electrochemical oxidation of 50 mg/L 2,4,6-TCP process, the 3DG-SnO2 anode displayed higher electrochemical activity with degradation efficiency of 100% and COD degradation efficiency of 75.48% after 120 min of electrolysis, and its average current efficiency is 1.47 times than that of SnO2 anode. A quadratic model was also developed by response surface analysis to predict the 2,4,6-TCP removal efficiency. Under optimized conditions (initial 2,4,6-TCP concentration = 200 mg/L, current density = 23.54 mA/cm2, Na2SO4 concentration = 0.19 mol/L, pH = 8.16), the 2,4,6-TCP removal efficiency reached up to 99.77% after 60 min of electrolysis. Moreover, the preferential attack sites of 2,4,6-TCP by OH radicals were also predicted by theoretical calculations and the specific degradation products were identified by GC-MS. Three plausible degradation pathways were proposed accordingly.

Toward green nano adsorbents and catalysts: Highly active Fe/Mn nanoparticles for enhanced oxidation of oxytetracycline and levofloxacin

The widespread use of antibiotics, such as oxytetracycline (OTC) and levofloxacin (LEV), has led to dangerous levels of environmental contamination. In this study, functionalized iron/manganese nanoparticles (Fe/Mn NPs), which act as both adsorbent and Fenton catalyst, were green-synthesized using a reducing agent derived from a tea extract. The resulting pre-sorption/Fenton-like oxidation system effectively removed both OTC and LEV from the aqueous solution with adsorption capacities of Fe/Mn NPs for OTC and LEV of 58.8 and 192.3 mg·g−1, respectively. In addition, Fe/Mn NPs also showed high catalytic activity, oxidizing more than 99.9 % of both OTC and LEV, while sodium persulfate (PDS) removed only 26.6 and 29.0 % of OTC and LEV, respectively. Mechanisms of PDS activation typically involve either catalyst-initiated or mediated electron transfer reactions. Fe/Mn NPs through heterogeneous catalytic and metal leaching-induced homogeneous Fenton reactions, which generated various reactive oxygen species (ROS) including 1O2, ·OH, SO4-· and ·O2–. Characterization of Fe/Mn NPs before and after reaction, and the identification of specific OTC and LEV degradation products by LC-MS, helped to elucidate a potential degradation pathway, as well as the removal mechanism. Finally, the practicality of using this system for wastewater treatment was demonstrated using real wastewater samples indicating that the system has great potential for simultaneously degrading both OTC and LEV in contaminated wastewater.

5,6-Dihydroxyindole eumelanin content in human skin with varying degrees of constitutive pigmentation.

Human skin contains two distinct components: brown to black, insoluble eumelanin and light colored, alkaline-soluble pheomelanin. Eumelanin consists of 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) moieties, while pheomelanin consists of benzothiazine (BT) and benzothiazole (BZ) moieties. These melanin monomer units can be quantitatively analyzed through specific degradation products by high-performance liquid chromatography (HPLC). Alkaline hydrogen peroxide oxidation (AHPO) of eumelanin gives rise to pyrrole-2,3,5-tricarboxylic acid (PTCA) and pyrrole-2,3-dicarboxylic acid (PDCA) as specific degradation products of the DHICA and DHI moieties, respectively. BZ moiety in pheomelanin can be analyzed as thiazole-2,4,5-tricarboxylic acid (TTCA). By reductive hydrolysis with hydroiodic acid, BT moieties in pheomelanin can be analyzed as 4-amino-3-hydroxyphenylalanine (4-AHP). As a recently improved AHPO-HPLC method enabled a better characterization of PDCA, this prompted us to address the question of DHI to DHICA ratio in human skin samples with varying degrees of constitutive pigmentation ranging from very light to dark. Results showed for the first time the ratio of 4 moieties: DHI 35%, DHICA 41%, BZ 20%, and BT 4%. The ratio is constant regardless of the degree of pigmentation. The high content of DHICA moiety may impart an antioxidant property to the epidermis melanin.

Insight into the mechanochemistry of the Maillard reaction: degradation of Schiff bases via 5-oxazolidinone intermediate

With the emergence of mechanochemistry as a fast and efficient synthetic methodology, we reported earlier that ball milling of glucose with histidine leads to the formation of reaction mixtures rich in Schiff bases. Upon subsequent thermal treatments, these mixtures exhibited enhanced reactivity generating more browning and pyrazine-rich volatiles, compared to non-milled samples. To rationalize these observations, we further investigated the mechanochemistry of the Maillard reaction using glycolaldehyde and histidine or phenylalanine as model systems. The conversion of Schiff bases into reactive 5-oxazolidinone in these model systems was proposed as the basis of the observed enhanced reactivity. Furthermore, the formation of 5-oxazolidinone in the ball-milled samples was verified through direct spectroscopic observation of its characteristic FTIR absorption band between 1780 cm−1 and 1810 cm−1 and through the identification of its specific degradation products. The important role of the carboxylic acid moiety in enabling the formation of reactive 5-oxazolidinone intermediate that facilitates its subsequent decarboxylation and formation of downstream degradation products such as dihydropyrazines and Strecker aldehydes were elucidated.

Association of Diabetic Kidney Disease Markers and Urinary Beta-crossLaps in Type 2 Diabetes

Introduction: Diabetic Kidney Disease (DKD) is a chronic complication in Type 2 diabetes. The Chronic Kidney Disease (CKD273) peptide classifier has been found to predict development of DKD even before microalbuminuria develops. Seventy four percent of peptides in the CKD273 classifier are Collagen degradation fragments. The Beta-CrossLaps (β-CTx) Enzyme Llinked Immunosorbent Assay (ELISA) assay detects the specific collagen degradation product, C terminal telopeptide of Type 1 collagen. In light of the Capillary Electrophoresis/Mass Spectrometry (CE-MS) findings, linking collagen degradation fragments excretion to early detection of DKD, the significance of urinary β-CTx levels as a DKD biomarker needs to be evaluated. Aim: To study the urinary excretion of β-CTx in type 2 diabetes patients and to evaluate its relation to Microalbuminuria status and estimated Glomerular Filtration Rate (eGFR) of the patients. Materials and Methods: This descriptive cross-sectional study was undertaken at a tertiary care hospital, with enrollment of 82 type 2 diabetes patients from the diabetes Out Patient Department (OPD) Participants were divided into groups based on their Urinary Albumin Creatinine Ratio (UACR) and eGFR levels. The study participants were tested for Urinary β-CTx level, UACR and eGFR. Mean or median was calculated for the parameters with normal and non-normal distribution, respectively. All statistical testing was performed on online calculators available at the site; https://www.socscistatistics.com/. Results: The median urinary β-CTx level observed was 100.6 ng/mmol of creatinine. Among the 82 participants, 15 participants had urinary β-CTx level 15pg/mL, the sensitivity of the kit. Among the remaining 67 participants, the minimum Urinary Beta-CrossLaps: Creatinine ratio observed was 2.6 ng/mmol and the maximum value observed was 2071 ng/mmol (i.e., 2.1 μg/mmol). The median urinary β-CTx level was highest (100.6 ng/mmol creatinine) in the patient group with eGFR in the normal range. The urinary β-CTx level was found to decline with decline in eGFR, with median urinary β-CTx 65.5 ng/mmol creatinine in the patient group with mildly decreased eGFR and 7.2 ng/mmol creatinine in the patient group with moderately decreased eGFR. Conclusion: The Urinary β-CTx concentration in type 2 diabetes patients is dispersed over a wide range. The Urinary β-CTx concentration correlates with the eGFR of the patient and is not influenced by age, gender or duration of diabetes. This parameter is a potential early DKD biomarker.

Impact of experimental thermal processing of artificially contaminated pea products on ochratoxin A and phomopsin A

Fungi of Aspergillus and Penicillium genus can infect peas (Pisum sativum), leading to a contamination with the nephrotoxic and carcinogenic ochratoxin A (OTA). Under unfavourable conditions, a fungus primarily found on lupines, Diapothe toxica, may also grow on peas and produce the hepatotoxic phomopsin A (PHOA). To study the effect of processing on OTA and PHOA content, two model products—wheat/rye-mixed bread with pea flour addition and pea pasta—were manufactured at small-business scale from artificially contaminated pea flour. The decrease of OTA and PHOA contents were monitored along the production process as indicators for toxin transformation. Pea bread dough was subjected to proofing for 30–40 min at 32 °C and baked at 250 °C to 230 °C for 40 min. OTA content (LODs < 0.1 μg/kg) showed a reduction in the bread crust (initially 17.0 μg/kg) to 88% and no reduction in the crumb (110%). For PHOA (LODs < 3.6 μg/kg), a decrease to approximately 21% occurred in the bread crust (initially 12.5 μg/kg), whilst for crumb, a less intense decrease to 91% was found. Pea pasta prepared with two toxin levels was extruded at room temperature, dried and cooked for 8 min in boiling water. In pea pasta, OTA was reduced from 29.8 to 13.9 μg/kg by 22% each after cooking, whilst 15% and 10% of the initial toxin amounts were found in the cooking water, respectively. For PHOA, 60% and 78% of initially 14.3 μg/kg and 7.21 μg/kg remained in the cooked pasta. As only the decrease of the initial content was measured and no specific degradation products could be detected, further research is needed to characterise potential transformation products. Heat treatment reduces the initial PHOA content stronger than the OTA content during pasta cooking and bread making. However, significant amounts of both toxins would remain in the final products.

Pre-adsorption and Fenton-like oxidation of mitoxantrone using hybrid green synthesized rGO/Fe nanoparticles

Emerging contaminants such as Mitoxantrone (MTX) are a major environmental concern because they have potential genotoxicity and mutagenesis to both aquatic organisms and humans. In this study, a pre-adsorption/Fenton-like oxidation system was developed which used a reduced graphene oxide/iron nanoparticles hybrid (rGO/Fe NPs) as both the adsorbent and the Fenton catalyst to remove MTX from solution. While the addition of H2O2 alone removed only 11.3% of MTX, the rGO/Fe NPs/H2O2 system was significantly more efficient removing 99.8% of MTX in the same period. This indicated that rGO/Fe NPs had excellent catalytic activity even at pH 7. This efficient removal was attributed to significant production of ·OH mainly by heterogeneous catalysis but supplemented by a homogeneous Fenton reaction, where ·OH had a higher affinity for MTX than SO4−·. The sequential Fenton-like oxidation process best fits a pseudo-second-order kinetic model (R2 ≥ 0.974). Characterizations of rGO/Fe NPs before and after the reaction, together with the identification of specific MTX degradation products, allowed possible degradation pathways to be proposed together with insights into the underlying mechanisms of MTX degradation when using rGO/Fe NPs in a pre-adsorption/Fenton-like oxidation system. Finally, the rGO/Fe NPs developed was successfully applied for the removal of MTX from spiked wastewater with 93.6% removal efficiency, which indicated that the proposed system had significant potential for wastewater treatment applications.

Medication Safety in Intravenous Therapy: A Compatibility Study and Analysis of Reaction Products of Dihydralazine and Metamizole

The pharmacotherapy of critically ill patients is challenging due to the variety of drugs that have to be applied. As the majority of pharmaceuticals must be administered intravenously because of the critical condition of the patients, the compatibility of co-applied intravenous drugs is crucial for a safe and successful infusion therapy. Antihypertensive therapy was reported by health care professionals to be ineffective in association with concomitant application of dihydralazine and metamizole (dipyrone). As both drugs are administered in German intensive care units, we analyzed their compatibility, examined the mechanisms of underlying dihydralazine degradation, and identified reaction products of dihydralazine and metamizole. Binary combinations were prepared at the high and the low end of the nominal administration concentration. Validated high performance liquid chromatography/ultraviolet absorption (HPLC-UV) analysis was conducted to quantify drug amount and high performance liquid chromatography/mass spectrometry (HPLC-MS) was used to analyze degradation products. The combinations of dihydralazine and metamizole proved to be incompatible as dihydralazine concentration decreased immediately and considerably. Metamizole also slightly decreased over time. Specific degradation products of dihydralazine were identified and a degradation pathway was postulated. Our findings demonstrate that the intravenous co-administration of dihydralazine and metamizole should be strictly avoided due to the incompatibility of these two drugs.

Potential role of full-length and nonfull-length progranulin in affecting aortic valve calcification

Inflammation is implicated in the pathogenesis of calcific aortic valve disease (CAVD) which is a major contributor to cardiovascular mortality and lacks non-surgical treatment. The progranulin (PGRN) is an important immunomodulatory factor in a variety of inflammatory diseases, including rheumatoid arthritis, osteoarthritis, inflammatory bowel disease and pneumonia. However, its role in calcification of aortic valve remains unknown.We firstly found that PGRN was increased in calcified human aortic valve (AV) tissues. Interestingly, in addition to full-length PGRN (68KD), a much stronger band of approximately 45 KD was also significantly increased. The band of 45 KD (45-GRN), was present in wild type (WT) mouse MEFs and AV but absent in grn−/−MEFs, indicating that it was a specific degradation product derived from PGRN. 45-GRN was upregulated whereas PGRN was reduced in human valve interstitial cells (hVICs) under calcifying conditions which is induced by osteogenic medium (OM). In primary porcine VICs (pVICs), PGRN downregulated TNF-α and α-SMA which was accompanied by downregulation of RUNX2, OPN, OCN, alkaline phosphatase activity and calcium deposition, effects pointing to reduced inflammation, myofibroblastic and osteoblastic transition under calcifying conditions. We overexpressed a mimic of 45-GRN which contains p-G-F-B-A-C in pVICs. However, 45-GRN overexpression promoted OM-induced calcification through activating the Smad1/5/8, NF-κB and AKT signaling pathways. Inhibition of the three signaling pathways suppressed 45-GRN's effect on VICs phenotype transition. 45-GRN promoted TNF-α and expressed converse pathogenic signatures with PGRN during TNF-α stimulation.Collectively, this study provides new insight into the pathogenesis of CAVD, indicating that PGRN is a stratagem in mitigating valve fibrosis/osteoblastic differentiation, and also presenting 45-GRN as a potential target for the treatment of CAVD.

D-dimer: A Marker of Severity in COVID-19

Introduction: The ever-growing number of COVID-19 patients stresses upon the need to identify effective yet readily available predictors of disease severity to ensure better clinical outcomes. D-dimer is a fibrin specific degradation product derived by enzymatic action of plasmin on factor XIIIa cross-linked fibrin. It serves as an ideal marker for activation of coagulation and fibrinolytic pathways. Identification of coagulopathy as an important complication in COVID-19 patients has brought to focus D-dimer as a possible predictor of clinical severity in patients. Aim: In this study, we analysed the role of D-dimer levels in assessing the clinical severity of the COVID-19 patients. Materials and Methods: We enrolled 217 in-patients of Tirunelveli Medical College in this single centre observational study and classified them into asymptomatic, mild, moderate and severe according to “Clinical Management Protocol: COVID 19”, by the Ministry of Health and Family Welfare and Director General of Health Services. D-dimer was estimated in the separated plasma, using latex based assay using semi-automated coagulation analyser. Data were presented as percentages for categorical variables and median±Inter Quartile Range (IQR) for continuous variables. Chi-square test was used to compare the D-dimer values between symptomatic and asymptomatic groups. A value of p&lt;0.05 was considered statistically significant. Results: Among the 217 cases, 88.9% were asymptomatic cases, 8.8% presented with mild clinical severity and 2.3% had moderate clinical presentation. In our study population, the Mean±SD and Median±IQR of D-dimer values (in ng/mL) were 223.4±230.6 and 157.0±187.7, respectively. The mean D-dimer value was found to increase as the category of our study group ascended from asymptomatic patients to mild and moderate clinical cases. It was noted that 91.1% of the cases who had D-dimer values &lt;500 ng/mL were asymptomatic. Also, the odds of patients with high levels of D-dimer being clinically symptomatic was 5.5 times more than the odds of patients with D-dimer levels &lt;500 ng/mL. Conclusion: Elevation of D-dimer levels associated with the severity of clinical course of patients infected with SARS CoV-2 when compared to patients with mild or asymptomatic clinical presentations.

Specific elastin degradation products are associated with poor outcome in the ECLIPSE COPD cohort

Chronic obstructive pulmonary disease (COPD) is characterized by a slow heterogeneous progression. Therefore, improved biomarkers that can accurately identify patients with the highest likelihood of progression and therefore the ability to benefit from a given treatment, are needed. Elastin is an essential structural protein of the lungs. In this study, we investigated whether elastin degradation products generated by the enzymes proteinase 3, cathepsin G, neutrophil elastase, MMP7 or MMP9/12 were prognostic biomarkers for COPD-related outcomes. The elastin degradome was assessed in a subpopulation (n = 1307) of the Evaluation of COPD Longitudinally to Identify Predictive Surrogate End-points (ECLIPSE) cohort with 3 years of clinical follow-up. Elastin degraded by proteinase 3 could distinguish between COPD participants and non-smoking controls (p = 0.0006). A total of 30 participants (3%) died over the 3 years of observation. After adjusting for confounders, plasma levels of elastin degraded by proteinase 3 and cathepsin G were independently associated with mortality outcome with a hazard ratio per 1 SD of 1.49 (95%CI 1.24–1.80, p < 0.0001) and 1.31 (95%CI 1.10–1.57, p = 0.0029), respectively. Assessing the elastin degradome demonstrated that specific elastin degradation fragments have potential utility as biomarkers identifying subtypes of COPD patients at risk of poor prognosis and supports further exploration in confirmatory studies.

PLASMA DESMOSINE, AN ELASTIN DEGRADATION PRODUCT, PREDICTS OUTCOMES IN AT RISK POPULATIONS

Recent evidence suggest that elastin fragmentation plays a key role in plaque destabilization and rupture. Plasma desmosine is an elastin specific degradation product. We have reviewed the predictive value of plasma desmosine for outcome in a cohort of patient with cardiovascular disease and in 2

Low-femtogram sensitivity analysis of polyaromatic hydrocarbons using GC-APLI-TOF mass spectrometry: Extending the target window for aromatic steroids in early Proterozoic rocks

Reading the molecular record of early life on Earth can be challenging as a consequence of the thermal decomposition of biomarker hydrocarbons during extended and deep sedimentary burial. Biomarkers that appear absent may still exist in concentrations far below the detection limit of regular analytical techniques. Hence thermal maturation and analytical limitations form a major hurdle for the unambiguous reconstruction of Earth’s earliest ecosystems. Specific degradation products of hopanes and steranes might still carry diagnostic value for the reconstruction of past biota when found in mature oils and sediment extracts, but their concentrations are often exceedingly low. We here report on the use of gas chromatography–time-of-flight-mass spectrometry with laser ionization at atmospheric pressure (GC-APLI-TOF-MS) for the identification and quantification of aromatic steroids. GC-APLI-TOF-MS analyses of a reference oil revealed that triaromatic steroids (TAs) can be detected with significantly higher sensitivity and selectivity compared to commonly used electron impact ionization GC-MS in selected ion monitoring mode, while the limit of detection for retene was as low as 25 fg on column. Paleoproterozoic (1.64 Ga) sedimentary rocks of the Barney Creek Formation yield the so far oldest unambiguous aromatic steroids. GC-APLI-TOF-MS applied to these rocks revealed the presence of TAs in even deeper parts of this succession, where they are represented by short chain homologues only. While the TA-I/(TA-I + TA-II) parameter is principally controlled by thermal degradation of longer chain homologues, the complete disappearance of TA-II already at 435–442 °C Tmax, may point towards an uncommon thermal gradient in the Barney Creek Formation or towards other influencing factors. GC-APLI-TOF-MS proves to be a highly promising tool that might extend molecular geobiological approaches to older sedimentary basins that were hitherto precluded from organic geochemical approaches by their elevated thermal maturity.

The Expression of Thrombospondin-4 Correlates with Disease Severity in Osteoarthritic Knee Cartilage.

Osteoarthritis (OA) is a progressive joint disease characterized by a continuous degradation of the cartilage extracellular matrix (ECM). The expression of the extracellular glycoprotein thrombospondin-4 (TSP-4) is known to be increased in injured tissues and involved in matrix remodeling, but its role in articular cartilage and, in particular, in OA remains elusive. In the present study, we analyzed the expression and localization of TSP-4 in healthy and OA knee cartilage by reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry, and immunoblot. We found that TSP-4 protein expression is increased in OA and that expression levels correlate with OA severity. TSP-4 was not regulated at the transcriptional level but we detected changes in the anchorage of TSP-4 in the altered ECM using sequential protein extraction. We were also able to detect pentameric and fragmented TSP-4 in the serum of both healthy controls and OA patients. Here, the total protein amount was not significantly different but we identified specific degradation products that were more abundant in sera of OA patients. Future studies will reveal if these fragments have the potential to serve as OA-specific biomarkers.