ABSTRACT
BACKGROUND: To determine whether a decrease in serum (1,3)-ß-D-glucan (BDG) was associated with reduced mortality and to investigate the performance of BDG downslope in predicting clinical outcome in invasive candidiasis. METHODS: Observational cohort study in ICU patients over a ten-year period (2012-2022) in Italy. Proven invasive candidiasis with at least 2 BDG determinations were considered. RESULTS: In the study population of 103 patients (age 47 [35-62] years, SAPS II score 67 [52-77]) 68 bloodstream and 35 intrabdominal infections were recorded. Serial measurements showed that in 54 patients BDG decreased over time (BDG downslope group) while in 49 did not (N-BDG downslope group). Candida albicans was the pathogen most frequently isolated (61%) followed by C. parapsilosis (17%) and C. glabrata (12%), in absence of any inter-group difference. Invasive candidiasis related mortality was lower in BDG downslope than in N-BDG downslope group (17% vs 53%, p < 0.01). The multivariate Cox regression analysis showed the association of septic shock at infection occurrence and chronic liver disease with invasive candidiasis mortality (HR [95% CI] 3.24 [1.25-8.44] p = 0.02 and 7.27 [2.33-22.66] p < 0.01, respectively) while a BDG downslope was the only predictor of survival (HR [95% CI] 0.19 [0.09-0.43] p < 0.01). The area under the receiver operator characteristic curve for the performance of BDG downslope as predictor of good clinical outcome was 0.74 (p = 0.02) and our model showed that a BDG downslope > 70% predicted survival with both specificity and positive predictive value of 100%. CONCLUSIONS: A decrease in serum BDG was associated with reduced mortality and a steep downslope predicted survival with high specificity in invasive candidiasis.
Subject(s)
Candidiasis, Invasive , Intensive Care Units , beta-Glucans , Humans , Middle Aged , Male , Candidiasis, Invasive/blood , Candidiasis, Invasive/mortality , Candidiasis, Invasive/diagnosis , Female , Intensive Care Units/statistics & numerical data , Intensive Care Units/organization & administration , beta-Glucans/blood , beta-Glucans/analysis , Prognosis , Adult , Cohort Studies , Italy/epidemiology , Biomarkers/blood , Biomarkers/analysis , Proteoglycans/blood , Proteoglycans/analysis , Predictive Value of TestsABSTRACT
BACKGROUND: Strategies for articular cartilage repair need to take into account topographical differences in tissue composition and architecture to achieve durable functional outcome. These have not yet been investigated in the equine stifle. OBJECTIVES: To analyse the biochemical composition and architecture of three differently loaded areas of the equine stifle. We hypothesise that site differences correlate with the biomechanical characteristics of the cartilage. STUDY DESIGN: Ex vivo study. METHODS: Thirty osteochondral plugs per location were harvested from the lateral trochlear ridge (LTR), the distal intertrochlear groove (DITG) and the medial femoral condyle (MFC). These underwent biochemical, biomechanical and structural analysis. A linear mixed model with location as a fixed factor and horse as a random factor was applied, followed by pair-wise comparisons of estimated means with false discovery rate correction, to test for differences between locations. Correlations between biochemical and biomechanical parameters were tested using Spearman's correlation coefficient. RESULTS: Glycosaminoglycan content was different between all sites (estimated mean [95% confidence interval (CI)] for LTR 75.4 [64.5, 88.2], for intercondylar notch (ICN) 37.3 [31.9, 43.6], for MFC 93.7 [80.1109.6] µg/mg dry weight), as were equilibrium modulus (LTR2.20 [1.96, 2.46], ICN0.48 [0.37, 0.6], MFC1.36 [1.17, 1.56] MPa), dynamic modulus (LTR7.33 [6.54, 8.17], ICN4.38 [3.77, 5.03], MFC5.62 [4.93, 6.36] MPa) and viscosity (LTR7.49 [6.76, 8.26], ICN16.99 [15.88, 18.14], MFC8.7 [7.91,9.5]°). The two weightbearing areas (LTR and MCF) and the non-weightbearing area (ICN) differed in collagen content (LTR 139 [127, 152], ICN176[162, 191], MFC 127[115, 139] µg/mg dry weight), parallelism index and angle of collagen fibres. The strongest correlations were between proteoglycan content and equilibrium modulus (r: 0.642; p: 0.001), dynamic modulus (r: 0.554; p < 0.001) and phase shift (r: -0.675; p < 0.001), and between collagen orientation angle and equilibrium modulus (r: -0.612; p < 0.001), dynamic modulus (r: -0.424; p < 0.001) and phase shift (r: 0.609; p < 0.001). MAIN LIMITATIONS: Only a single sample per location was analysed. CONCLUSIONS: There were significant differences in cartilage biochemical composition, biomechanics and architecture between the three differently loaded sites. The biochemical and structural composition correlated with the mechanical characteristics. These differences need to be acknowledged by designing cartilage repair strategies.
INTRODUCTION/CONTEXTE: Les stratégies de réparation du cartilage articulaire doivent tenir compte des différences topographiques en ce qui a trait à la composition et l'architecture des tissues, afin d'obtenir un résultat durable et fonctionnel. Cellesci n'ont pas encore été étudiées chez le grasset équin. OBJECTIFS: Analyser la composition biochimique et l'architecture de trois régions du grasset portant une quantité de poids différente. Nous émettons l'hypothèse que les différences entre régions seront corrélées aux caractéristiques biomécaniques du cartilage. TYPE D'ÉTUDE: Étude ex vivo. MÉTHODES: Trente échantillons ostéochondraux par site ont été récoltés à partir de la lèvre latérale de la trochlée fémorale (LTR), le sillon intertrochléaire distal (DITG) et le condyle fémoral médial (MFC). Ceuxci ont été soumis à des tests biochimiques, biomécaniques et une analyse structurelle. Un modèle linéaire mixte avec localisation comme facteur fixe et cheval comme facteur randomisé a été appliqué. Puis, ont suivi des comparaisons par paires de moyennes estimées avec contrôle du taux de fausses découvertes, pour tester les différences entre les divers sites. Les corrélations entre les paramètres biochimiques et biomécaniques ont été testé par le coefficient de corrélation Spearman. RÉSULTATS: Le contenu en glycosaminoglycans était différent à chacun des sites (moyenne estimée [95% CI] pour LTR 75.4 [64.5, 88.2], pour ICN 37.3 [31.9, 43.6], pour MFC 93.7[80.1109.6]µg/mg matière sèche), tout comme le module d'équilibre (LTR2.20 [1.96, 2.46], ICN0.48 [0.37, 0.6], MFC1.36 [1.17, 1.56] MPa), le module dynamique (LTR7.33 [6.54, 8.17], ICN4.38[3.77, 5.03], MFC5.62[4.93, 6.36] MPa) et la viscosité (LTR7.49[6.76, 8.26], ICN16.99 [15.88, 18.14], MFC8.7 [7.91, 9.5]°). Les deux régions portant du poids (LTR et MFC) et la région ne supportant pas de poids (ICN) diffèrent par rapport à leur contenu en collagène (LTR 139 [127152], ICN176 [162191], MFC 127 [115139] µg/mg matière sèche), à l'index de parallélisle et à l'angle des fibres de collagène. Les corrélations les plus fortes étaient entre le contenu en protéoglycans et le module d'équilibre (r: 0.642; p: 0.001), le module dynamique (r: 0.554; p < 0.001) et le changement de phase (r:−0.675; p < 0.001), et entre l'angle d'orientation du collagène et le module d'équilibre (r:−0.612; p < 0.001), le module dynamique (r:−0.424; p < 0.001) et le changement de phase (r: 0.609;p:<0.001). LIMITES PRINCIPALES: Seulement un échantillon par site a été soumis aux analyses. CONCLUSIONS: Il existe des différences significatives dans la composition biochimique, biomécanique et l'architecture du cartilage entre les trois sites échantillonnés. La composition biochimique et structurelle corrèle avec les caractéristiques mécaniques. Ces différences doivent être prises en compte lors de la création de stratégies de réparation du cartilage.
Subject(s)
Cartilage, Articular , Animals , Horses , Cartilage, Articular/chemistry , Stifle/chemistry , Proteoglycans/analysis , Glycosaminoglycans/analysis , Collagen/analysis , Biomechanical PhenomenaABSTRACT
INTRODUCTION: Aberrant gait variability has been observed after anterior cruciate ligament reconstruction (ACLR), yet it remains unknown if gait variability is associated with early changes in cartilage composition linked to osteoarthritis development. Our purpose was to determine the association between femoral articular cartilage T1ρ magnetic resonance imaging relaxation times and gait variability. METHODS: T1ρ magnetic resonance imaging and gait kinematics were collected in 22 ACLR participants (13 women; 21 ± 4 yr old; 7.52 ± 1.43 months post-ACLR). Femoral articular cartilage from the ACLR and uninjured limbs were segmented into anterior, central, and posterior regions from the weight-bearing portions of the medial and lateral condyles. Mean T1ρ relaxation times were extracted from each region and interlimb ratios (ILR) were calculated (i.e., ACLR/uninjured limb). Greater T1ρ ILR values were interpreted as less proteoglycan density (worse cartilage composition) in the injured limb compared with the uninjured limb. Knee kinematics were collected at a self-selected comfortable walking speed on a treadmill with an eight-camera three-dimensional motion capture system. Frontal and sagittal plane kinematics were extracted, and sample entropy was used to calculate kinematic variability structure (KV structure ). Pearson's product-moment correlations were conducted to determine the associations between T1ρ and KV structure variables. RESULTS: Lesser frontal plane KV structure was associated with greater mean T1ρ ILR in the anterior lateral ( r = - 0.44, P = 0.04) and anterior medial condyles ( r = - 0.47, P = 0 .03). Lesser sagittal plane KV structure was associated with greater mean T1ρ ILR in the anterior lateral condyle ( r = - 0.47, P = 0.03). CONCLUSIONS: The association between less KV structure and worse femoral articular cartilage proteoglycan density suggests a link between less variable knee kinematics and deleterious changes joint tissue changes. The findings suggest that less knee kinematic variability structure is a mechanism linking aberrant gait to early osteoarthritis development.
Subject(s)
Anterior Cruciate Ligament Injuries , Cartilage, Articular , Osteoarthritis, Knee , Humans , Female , Anterior Cruciate Ligament Injuries/surgery , Gait , Knee Joint , Cartilage, Articular/chemistry , Osteoarthritis, Knee/pathology , Magnetic Resonance Imaging/methods , Proteoglycans/analysis , Biomechanical PhenomenaABSTRACT
Intervertebral disc degeneration (IDD) is closely related to changes in the intervertebral disc (IVD) composition and the resulting viscoelastic properties. IDD is a severe condition because it decreases the disc's ability to resist mechanical loads. Our research aims to understand IDD at the cellular level, specifically the changes in the viscoelastic properties of the nucleus pulposus (NP), which are poorly understood. This study employed a system integrating nanoindentation with Raman spectrometry to correlate biomechanics with subtle changes in the biochemical makeup of the NP. The characterization was, in turn, correlated with the degenerative severity of IVD as assessed using magnetic resonance imaging (MRI) of different patients with spinal stenosis, degenerative spondylolisthesis, and degenerative scoliosis. It is shown that there is an increase in the crosslinking ratio in collagen, a reduction in proteoglycan, and a build-up of minerals upon the rise in the severity level of the disc damage in the NP. Assessment of mechanical characteristics reveals that the increasing disc degeneration makes the NP lose its elasticity, becoming more viscous. This shows that the tissue undergoes abnormalities in weight-bearing ability, which contributes to spinal instability. The correlation of the individual discs shows that grades III and IV have similarities in the changes of Amide I and III toward the storage modulus. In contrast, grades IV and V correlate with mineralization toward the storage modulus. Reduction of proteoglycan has the highest impact on the changes of the storage modulus in all grades of IDD. Connecting compositional alterations to IVD micromechanics at various degrees of degeneration expands our understanding of tissue behavior and provides critical insight into clinical diagnostics, treatment, and tissue engineering.
Subject(s)
Intervertebral Disc Degeneration , Intervertebral Disc , Nucleus Pulposus , Humans , Nucleus Pulposus/pathology , Intervertebral Disc Degeneration/pathology , Intervertebral Disc/pathology , Magnetic Resonance Imaging/methods , Proteoglycans/analysisABSTRACT
Fibrillar collagen-integrin interactions in the extracellular matrix (ECM) regulate a multitude of cellular processes and cell signalling. Collagen I fibrils serve as the molecular scaffolding for connective tissues throughout the human body and are the most abundant protein building blocks in the ECM. The ECM environment is diverse, made up of several ECM proteins, enzymes, and proteoglycans. In particular, glycosaminoglycans (GAGs), anionic polysaccharides that decorate proteoglycans, become depleted in the ECM with natural aging and their mis-regulation has been linked to cancers and other diseases. The impact of GAG depletion in the ECM environment on collagen I protein interactions and on mechanical properties is not well understood. Here, we integrate ELISA protein binding assays with liquid high-resolution atomic force microscopy (AFM) to assess the effects of GAG depletion on the interaction of collagen I fibrils with the integrin α2I domain using separate rat tails. ELISA binding assays demonstrate that α2I preferentially binds to GAG-depleted collagen I fibrils in comparison to native fibrils. By amplitude modulated AFM in air and in solution, we find that GAG-depleted collagen I fibrils retain structural features of the native fibrils, including their characteristic D-banding pattern, a key structural motif. AFM fast force mapping in solution shows that GAG depletion reduces the stiffness of individual fibrils, lowering the indentation modulus by half compared to native fibrils. Together these results shed new light on how GAGs influence collagen I fibril-integrin interactions and may aid in strategies to treat diseases that result from GAG mis-regulation.
Subject(s)
Extracellular Matrix , Glycosaminoglycans , Rats , Humans , Animals , Glycosaminoglycans/analysis , Glycosaminoglycans/chemistry , Glycosaminoglycans/metabolism , Extracellular Matrix/chemistry , Proteoglycans/analysis , Proteoglycans/metabolism , Microscopy, Atomic Force , Collagen/chemistryABSTRACT
AIMS: (a) The aim of this study was to investigate both the formation of dense connective tissue within the dental pulp, and its association with pulpal inflammation in teeth with advanced carious lesions; and (b) to investigate in vitro whether inflammation affects the expression of markers related to chondrogenesis/osteogenesis in pulp cells. MATERIALS AND METHODS: Radiology and Histology: Forty-six teeth with advanced carious lesions were radiographically investigated for intra-pulpal radiodense structures. Specimens were processed for histology and stained with haematoxylin/eosin and proteoglycan-specific stains. The intra-pulpal connective tissue was scored as pulp stones or ectopic connective tissue. Cell culture: pulpal cells from human third molars (n = 5) were cultured in chondrogenic medium +/- TLR2/4 agonists. Expression of the genes IL6, TLR2/4, SOX9, COL1A1, COL2A1, TGFB1, RUNX2 and ALPL was assessed by qPCR. Proteoglycan content within cultures was assessed spectrophotometrically. RESULTS: Radiodense structures were discovered in about half of all pulps. They were associated with ectopic connective tissue (χ2 = 8.932, p = .004, OR = 6.80, 95% CI: [1.84, 25.19]) and with pulp stones (χ2 = 12.274, df = 1, p < .001, OR = 22.167, 95% CI: [2.57, 200.00]). The morphology of the ectopic tissue resembled cartilage and was associated with inflammatory infiltration of the pulp (χ2 = 10.148, p = .002, OR = 17.77, 95% CI: [2.05, 154.21]). After continuous stimulation of cultured cells with TLR2/4 agonists, the expression of two inflammatory markers increased: IL6 at Days 7 (p = .020) and 14 (p = .008); TLR2 at Days 7 (p = .023) and 14 (p = .009). Similarly, expression of chondrogenic markers decreased: SOX9 at Day 14 (p = .035) and TGFB1 at Day 7 (p = .004), and the osteogenic marker COL1A1 at Day 7 (p = .007). Proteoglycan content did not differ between unstimulated and stimulated cells. CONCLUSIONS: Ectopic connective tissue resembling cartilage can form in teeth affected by advanced carious lesions. This tissue type is radiographically visible and is associated with inflammatory infiltration of the pulp. Although TLR2/4 agonists led to an inflammatory response in cell culture of pulp cells, the effect on the expression of osteogenic/chondrogenic markers was limited, suggesting that immune cells are needed for connective tissue formation in vivo.
Subject(s)
Dental Caries , Dental Pulp Calcification , Ossification, Heterotopic , Biomarkers/metabolism , Chondrogenesis , Connective Tissue/pathology , Core Binding Factor Alpha 1 Subunit/metabolism , Dental Caries/metabolism , Dental Pulp , Eosine Yellowish-(YS)/analysis , Eosine Yellowish-(YS)/metabolism , Humans , Inflammation/metabolism , Interleukin-6/metabolism , Ossification, Heterotopic/metabolism , Ossification, Heterotopic/pathology , Proteoglycans/analysis , Proteoglycans/metabolism , Toll-Like Receptor 2/analysis , Toll-Like Receptor 2/metabolismABSTRACT
Proinflammatory cytokines target vascular endothelial cells during COVID-19 infections. In particular, the endothelial glycocalyx (eGC), a proteoglycan-rich layer on top of endothelial cells, was identified as a vulnerable, vasoprotective structure during infections. Thus, eGC damage can be seen as a hallmark in the development of endothelial dysfunction and inflammatory processes. Using sera derived from patients suffering from COVID-19, we could demonstrate that the eGC became progressively worse in relation to disease severity (mild vs severe course) and in correlation to IL-6 levels. This could be prevented by administering low doses of spironolactone, a well-known and highly specific aldosterone receptor antagonist. Our results confirm that SARS-CoV-2 infections cause eGC damage and endothelial dysfunction and we outline the underlying mechanisms and suggest potential therapeutic options.
Subject(s)
COVID-19 Drug Treatment , COVID-19 , Glycocalyx , Mineralocorticoid Receptor Antagonists , SARS-CoV-2 , Spironolactone , COVID-19/blood , COVID-19/pathology , Cytokines/pharmacology , Endothelial Cells/drug effects , Endothelial Cells/pathology , Glycocalyx/drug effects , Glycocalyx/pathology , Humans , Interleukin-6/blood , Mineralocorticoid Receptor Antagonists/pharmacology , Mineralocorticoid Receptor Antagonists/therapeutic use , Proteoglycans/analysis , Proteoglycans/blood , Spironolactone/pharmacology , Spironolactone/therapeutic useABSTRACT
Proteoglycans are heterogeneous macromolecular glycoconjugates that orchestrate many important cellular processes. While much attention has focused on the poly-sulfated glycosaminoglycan chains that decorate proteoglycans, other important elements of their architecture, such as core proteins and membrane localization, have garnered less emphasis. Hence, comprehensive structure-function relationships that consider the replete proteoglycan architecture as glycoconjugates are limited. Here we present an extensive approach to study proteoglycan structure and biology by fabricating defined semisynthetic modular proteoglycans that can be tailored for cell surface display. The expression of proteoglycan core proteins with unnatural amino acids permits bioorthogonal click chemistry with functionalized glycosaminoglycans for methodical dissection of the parameters required for optimal binding and function of various proteoglycan-binding proteins. We demonstrate that these sophisticated materials can recapitulate the functions of native proteoglycan ectodomains in mouse embryonic stem cell differentiation and cancer cell spreading while permitting the analysis of the contributing architectural elements toward function.
Subject(s)
Proteoglycans , Animals , Cell Membrane/metabolism , Mice , Proteoglycans/analysis , Proteoglycans/metabolismABSTRACT
Antiplatelet and anticoagulant drugs are classified antithrombotic agents with the purpose to reduce blood clot formation. For a successful treatment of many known complex cardiovascular diseases driven by platelet and/or coagulation activity, the need of more than one antithrombotic agent is inevitable. However, combining drugs with different mechanisms of action enhances risk of bleeding. Dual anticoagulant and antiplatelet (APAC), a novel semisynthetic antithrombotic molecule, provides both anticoagulant and antiplatelet properties in preclinical studies. APAC is entering clinical studies with this new exciting approach to manage cardiovascular diseases. For a better understanding of the biological function of APAC, comprehensive knowledge of its structure is essential. In this study, atomic force microscopy (AFM) was used to characterize APAC according to its structure and to investigate the molecular interaction of APAC with von Willebrand factor (VWF), since specific binding of APAC to VWF could reduce platelet accumulation at vascular injury sites. By the optimization of drop-casting experiments, we were able to determine the volume of an individual APAC molecule at around 600 nm3, and confirm that APAC forms multimers, especially dimers and trimers under the experimental conditions. By studying the drop-casting behavior of APAC and VWF individually, we depictured their interaction by using an indirect approach. Moreover, in vitro and in vivo conducted experiments in pigs supported the AFM results further. Finally, the successful adsorption of APAC to a flat gold surface was confirmed by using photothermal-induced resonance, whereby attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) served as a reference method.
Subject(s)
Anticoagulants/analysis , Heparin/analogs & derivatives , Microscopy, Atomic Force/methods , Platelet Aggregation Inhibitors/analysis , Proteoglycans/analysis , Heparin/analysis , Humans , Spectroscopy, Fourier Transform Infrared/methodsABSTRACT
OBJECTIVE: Spectroscopic techniques, such as near-infrared (NIR) spectroscopy, are gaining significant research interest for characterizing connective tissues, particularly articular cartilage, because there is still a largely unmet need for rapid, accurate and objective methods for assessing tissue integrity in real-time during arthroscopic surgery. This study aims to identify the NIR spectral range that is optimal for characterizing cartilage integrity by (a) identifying the contribution of its major constituents (collagen and proteoglycans) to its overall spectrum using proxy constituent models and (b) determining constituent-specific spectral contributions that can be used for assessment of cartilage in its physiological state. DESIGN: The NIR spectra of cartilage matrix constituent models were measured and compared with specific molecular components of organic compounds in the NIR spectral range in order to identify their bands and molecular assignments. To verify the identified bands, spectra of the model compounds were compared with those of native cartilage. Since water obscures some bands in the NIR range, spectral measurements of the native cartilage were conducted under conditions of decreasing water content to amplify features of the solid matrix components. The identified spectral bands were then compared and examined in the resulting spectra of the intact cartilage samples. RESULTS: As water was progressively eliminated from cartilage, the specific contribution of the different matrix components was observed to correspond with those identified from the proxy cartilage component models. CONCLUSION: Spectral peaks in the regions 5500 to 6250 cm-1 and 8100 to 8600 cm-1 were identified to be effective for characterizing cartilage proteoglycan and collagen contents, respectively.
Subject(s)
Cartilage, Articular , Arthroscopy , Cartilage, Articular/chemistry , Cartilage, Articular/diagnostic imaging , Collagen , Proteoglycans/analysis , Spectroscopy, Near-Infrared/methodsABSTRACT
Meniscal tears are a common orthopedic injury, yet their healing is difficult to assess post-operatively. This impedes clinical decisions as the healing status of the meniscus cannot be accurately determined non-invasively. Thus, the objectives of this study were to explore the utility of a goat model and to use quantitative magnetic resonance imaging (MRI) techniques, histology, and biomechanical testing to assess the healing status of surgically induced meniscal tears. Adiabatic T1ρ, T2, and T2* relaxation times were quantified for both operated and control menisci ex vivo. Histology was used to assign healing status, assess compositional elements, and associate healing status with compositional elements. Biomechanical testing determined the failure load of healing lesions. Adiabatic T1ρ, T2, and T2* were able to quantitatively identify different healing states. Histology showed evidence of diminished proteoglycans and increased vascularity in both healed and non-healed menisci with surgically induced tears. Biomechanical results revealed that increased healing (as assessed histologically and on MRI) was associated with greater failure load. Our findings indicate increased healing is associated with greater meniscal strength and decreased signal differences (relative to contralateral controls) on MRI. This indicates that quantitative MRI may be a viable method to assess meniscal tears post-operatively.
Subject(s)
Disease Models, Animal , Goats , Knee Injuries/pathology , Meniscus/pathology , Animals , Biomechanical Phenomena , Collagen/analysis , Goats/anatomy & histology , Humans , Knee Injuries/diagnostic imaging , Magnetic Resonance Imaging , Meniscus/diagnostic imaging , Pilot Projects , Proteoglycans/analysis , Wound HealingABSTRACT
This study compared the performance of near-infrared spectroscopy (NIRS) models on fresh and freeze-dried beef muscle samples to predict intramuscular connective tissue (IMCT) components and to determine whether the accuracy of the models differed among different muscles from beef cattle. The hypothesis was that the water content of muscle samples would negatively influence the accuracy of the models, which would differ among muscles. Fresh and freeze-dried samples (n = 171) of four muscles were used to develop NIRS models to predict the contents IMCT. For the total collagen content, the standard error of cross validation (SECV) for model using freeze-dried samples (0.75 mg OH-prol/g DM) was lower than that for model using fresh samples (0.84 mg OH-prol/g DM). For cross-links and proteoglycans, the SECV for models using fresh sample spectra was lower than that for models using freeze-dried sample spectra. The accuracy of the prediction of the models also differed among predicted muscle types.
Subject(s)
Connective Tissue , Red Meat/analysis , Animals , Cattle , Collagen/analysis , Freeze Drying , Muscle, Skeletal/chemistry , Proteoglycans/analysis , Spectroscopy, Near-Infrared/methods , Spectroscopy, Near-Infrared/veterinary , WaterABSTRACT
Cutaneous leishmaniasis (CL) is one of the illnesses caused by Leishmania parasite infection, which can be asymptomatic or severe according to the infecting Leishmania strain. CL is commonly diagnosed by directly detecting the parasites or their DNA in tissue samples. New diagnostic methodologies target specific proteins (biomarkers) secreted by the parasite during the infection process. However, specific bioreceptors for the in vivo or in vitro detection of these novel biomarkers are rather limited in terms of sensitivity and specificity. For this reason, we here introduce three novel peptides as bioreceptors for the highly sensitive and selective identification of acid phosphatase (sAP) and proteophosphoglycan (PPG), which have a crucial role in leishmaniasis infection. These high-affinity peptides have been designed from the conservative domains of the lectin family, holding the ability to interact with the biological target and produce the same effect than the original protein. The synthetic peptides have been characterized and the affinity and kinetic constants for their interaction with the targets (sAP and PPG) have been determined by a surface plasmon resonance biosensor. Values obtained for KD are in the nanomolar range, which is comparable to high-affinity antibodies, with the additional advantage of a high biochemical stability and simpler production. Pep2854 exhibited a high affinity for sAP (KD = 1.48 nM) while Pep2856 had a good affinity for PPG (KD 1.76 nM). This study evidences that these peptidomimetics represent a novel alternative tool to the use of high molecular weight proteins for biorecognition in the diagnostic test and biosensor devices for CL.
Subject(s)
Acid Phosphatase/analysis , Leishmania/isolation & purification , Leishmaniasis, Cutaneous/parasitology , Membrane Proteins/analysis , Peptides/chemistry , Proteoglycans/analysis , Protozoan Proteins/analysis , Surface Plasmon Resonance/methods , Binding Sites , Humans , Leishmania/enzymology , Leishmaniasis, Cutaneous/diagnosis , Models, Molecular , Peptides/chemical synthesis , Peptidomimetics/chemical synthesis , Peptidomimetics/chemistryABSTRACT
Cranial cruciate ligament disease and rupture (CCLD/R) is one of the most common orthopaedic conditions in dogs, eventually leading to osteoarthritis of the stifle joint. Certain dog breeds such as the Staffordshire bull terrier have an increased risk of developing CCLD/R. Previous studies into CCLD/R have found that glycosaminoglycan levels were elevated in cranial cruciate ligament (CCL) tissue from high-risk breeds when compared to the CCL from a low-risk breed to CCLD/R. Our objective was to determine specific proteoglycans/glycosaminoglycans in the CCL and to see whether their content was altered in dog breeds with differing predispositions to CCLD/R. Disease-free CCLs from Staffordshire bull terriers (moderate/high-risk to CCLD/R) and Greyhounds (low-risk to CCLD/R) were collected and key proteoglycan/glycosaminoglycans were determined by semi-quantitative Western blotting, quantitative biochemistry, quantitative reverse transcription polymerase chain reaction, and immunohistochemistry. Gene expression of fibromodulin (P = 0.03), aggrecan (P = 0.0003), and chondroitin-6-sulphate stubs (P = 0.01) were significantly increased, and for fibromodulin this correlated with an increase in protein content in Staffordshire bull terriers compared to Greyhound CCLs (P = 0.02). Decorin (P = 0.03) and ADAMTS-4 (P = 0.04) gene expression were significantly increased in Greyhounds compared to Staffordshire bull terrier CCLs. The increase of specific proteoglycans and glycosaminoglycans within the Staffordshire bull terrier CCLs may indicate a response to higher compressive loads, potentially altering their risk to traumatic injury. The higher decorin content in the Greyhound CCLs is essential for maintaining collagen fibril strength, while the increase of ADAMTS-4 indicates a higher rate of turnover helping to regulate normal CCL homeostasis in Greyhounds.
Subject(s)
Anterior Cruciate Ligament/chemistry , Dog Diseases/genetics , Genetic Predisposition to Disease/genetics , Joint Diseases/veterinary , Proteoglycans/analysis , ADAMTS4 Protein/analysis , ADAMTS4 Protein/genetics , Aggrecans/analysis , Aggrecans/genetics , Animals , Chondroitin Sulfates/analysis , Chondroitin Sulfates/genetics , Dogs , Fibromodulin/analysis , Fibromodulin/genetics , Gene Expression , Joint Diseases/genetics , Proteoglycans/genetics , Rupture, Spontaneous/genetics , Rupture, Spontaneous/veterinary , Species Specificity , StifleABSTRACT
Oligodendrocyte precursor cells (OPCs) are a fourth resident glial cell population in the mammalian central nervous system. They are evenly distributed throughout the gray and white matter and continue to proliferate and generate new oligodendrocytes (OLs) throughout life. They were understudied until a few decades ago when immunolabeling for NG2 and platelet-derived growth factor receptor alpha revealed cells that are distinct from mature OLs, astrocytes, neurons, and microglia. In this review, we provide a summary of the known properties of OPCs with some historical background, followed by highlights from recent studies that suggest new roles for OPCs in certain pathological conditions.
Subject(s)
Oligodendrocyte Precursor Cells/pathology , Oligodendrocyte Precursor Cells/physiology , Animals , Antigens/analysis , Antigens/metabolism , Cell Differentiation/physiology , Cell Proliferation/physiology , Glioma/genetics , Humans , Microscopy, Electron , Neurons , Oligodendrocyte Precursor Cells/metabolism , Oligodendrocyte Precursor Cells/ultrastructure , Oligodendroglia/physiology , Proteoglycans/analysis , Proteoglycans/metabolism , Signal Transduction/genetics , Signal Transduction/physiologyABSTRACT
AIMS: Severe reduction in nephron numbers that are characteristic of renal hypodysplasia (RHD) are one of the cause of childhood chronic kidney disease (CKD). Glomerular hyperfiltration, glomerular hypertrophy, progressive glomerular scarring, and interstitial fibrosis due to reduced nephron number are risk factors for CKD. In recent years, studies on specific markers for early diagnosis of renal failure and mortality have been carried out. The objectives of this study were to identify serum and urinary endocan levels that are expressed in glomerular endothelial cells and tubular epithelial cells in RHD. MATERIALS AND METHODS: 29 children with RHD were compared to 26 healthy controls in terms of serum and urinary endocan levels. RESULTS: The mean serum endocan level in the RHD group and the control group was 700.72 ± 323.19 and 426.86 ± 233.14 pg/mL, respectively. The mean serum endocan level was significantly higher (p = 0.003) in the RHD group. The mean urinary endocan level in the RHD group was 63.62 ± 92.46 pg/mL, and in the control group it was 80.26 ± 142.49 pg/mL. The mean urinary endocan level did not change between groups (p = 0.95). There was also a significant correlation between serum endocan level and uric acid level in the study group (r = 0.325, p = 0.028). CONCLUSION: To our knowledge, this was the first study that evaluated serum and urinary endocan levels in children with RHD. Although serum endocan level was found to be significantly higher in patients with RHD, further studies are needed to validate whether endocan could serve as a marker of poor renal prognosis in RHD.
Subject(s)
Kidney/abnormalities , Proteoglycans/analysis , Adolescent , Biomarkers/blood , Child , Female , Humans , Male , Proteoglycans/blood , Proteoglycans/urine , Renal Insufficiency, Chronic/etiologyABSTRACT
OBJECTIVE: The clinical success of focal metallic resurfacing implants depends largely on the friction between implant and opposing cartilage. Therefore, the present study determines the lubricating ability of the synovial fluid components hyaluronic acid (HA), proteoglycan 4 (PRG4) and a surface-active phospholipid (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, POPC), on the articulation between cartilage and a Cobalt Chromium Molybdenum (CoCrMo) implant surface, compared with two cartilage surfaces. METHODS: A ring-on-disk geometry was used to perform repeated friction measurements at physiologically relevant velocities (6 and 60 mm/s) using lubricants with an increasing number of components present. Shear measurements were performed in order to evaluate the viscosity. To ensure that it is clinically relevant to explore the effect of these components, the presence of PRG4 in synovial fluid obtained from primary and revision knee and hip implant surgeries was examined. RESULTS: PRG4 in the presence of HA was found to significantly reduce the coefficient of friction for both cartilage-cartilage and cartilage-CoCrMo interface. This is relevant, as it was also demonstrated that PRG4 is still present at the time of revision surgeries. The addition of POPC had no effect for either configurations. HA increased the viscosity of the lubricating fluid by one order of magnitude, while PRG4 and POPC had no effect. CONCLUSION: The present study demonstrates the importance of selecting the appropriate lubrication solution to evaluate implant materials with biotribology tests. Because PRG4 is a key component for reducing friction between cartilage and an opposing surface, developing coatings which bind PRG4 is recommended for cartilage resurfacing implants.
Subject(s)
Cartilage, Articular/physiology , Friction , Hip Prosthesis , Knee Prosthesis , Proteoglycans/analysis , Proteoglycans/physiology , Synovial Fluid/chemistry , Animals , Biomechanical Phenomena , CattleABSTRACT
BACKGROUND: Endothelial dysfunction and injury is a major pathophysiologic feature of sepsis. Sepsis is also the most frequent cause of acute kidney injury (AKI) in critically ill patients. Though most studies of AKI in sepsis have focused on tubular epithelial injury, the role of endothelial dysfunction and injury is less well studied. The goal of this study was first to investigate whether endothelial dysfunction and injury biomarkers were associated with severe AKI in sepsis patients. The second goal was to determine the best performing biomarker for severe AKI and whether this biomarker was associated with severe AKI across different etiologies of sepsis and clinical outcomes. METHODS: We studied adults with severe sepsis and acute respiratory failure (ARF) enrolled in the prospective observational Validating Acute Lung Injury markers for Diagnosis (VALID) study. Plasma endothelial dysfunction and injury biomarkers, including angiopoietin-2, soluble vascular endothelial cadherin (sVE-cadherin), endocan and syndecan-1, were measured at study enrollment. Primary analysis focused on the association between endothelial biomarker levels with severe AKI (defined as Kidney Disease: Improving Global Outcomes [KDIGO] AKI stage 2 or 3), other organ dysfunctions (defined by Brussels organ failure scores), and comparison of pulmonary versus non-pulmonary sepsis. RESULTS: Among 228 sepsis patients enrolled, 141 developed severe AKI. Plasma levels of angiopoietin-2, endocan, sVE-cadherin, and syndecan-1 were significantly higher in sepsis patients with severe AKI compared to those without severe AKI. Among four endothelial biomarkers, only angiopoietin-2 was independently associated with severe AKI (odds ratio 6.07 per log increase, 95% CI 2.34-15.78, p < 0.001). Plasma angiopoietin-2 levels by quartile were significantly higher in sepsis patients with hepatic, coagulation, and circulatory failure. Plasma angiopoietin-2 levels were also significantly higher in patients with non-pulmonary sepsis compared to subjects with pulmonary sepsis. CONCLUSION: Among four biomarkers of endothelial dysfunction and injury, angiopoietin-2 had the most robust independent association with development of severe AKI in patients with severe sepsis and ARF. Plasma angiopoietin-2 levels were also associated with other organ dysfunctions, non-pulmonary sepsis, and death. These findings highlight the importance of early endothelial dysfunction and injury in the pathogenesis of sepsis-induced AKI.
Subject(s)
Acute Kidney Injury/etiology , Angiopoietin-2/analysis , Sepsis/complications , Acute Kidney Injury/blood , Adult , Aged , Angiopoietin-2/blood , Biomarkers/analysis , Biomarkers/blood , Cadherins/analysis , Cadherins/blood , Chi-Square Distribution , Endothelium/physiopathology , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Male , Middle Aged , Neoplasm Proteins/analysis , Neoplasm Proteins/blood , Odds Ratio , Organ Dysfunction Scores , Prospective Studies , Proteoglycans/analysis , Proteoglycans/blood , Respiratory Insufficiency/blood , Respiratory Insufficiency/complications , Sepsis/blood , Statistics, Nonparametric , Syndecan-1/analysis , Syndecan-1/bloodABSTRACT
BACKGROUND: Environmental conditions strongly influence the healing capacity of connective tissues. Well-vascularized extrasynovial tendons typically undergo a robust wound-healing process following transection and repair. In contrast, avascular intrasynovial tendons do not mount an effective repair response. The current study tests the hypothesis that flexor tendons, as a function of their synovial environment, exhibit unique inflammatory, angiogenic, and metabolic responses to injury and repair. METHODS: Flexor tendons present a distinct opportunity to test the study hypothesis, as they have proximal regions that are extrasynovial and distal regions that are intrasynovial. In an internally controlled study design, the second and fifth forepaw flexor tendons were transected and repaired in either the extrasynovial or the intrasynovial anatomical region. Histological, gene expression, and proteomics analyses were performed at 3 and 7 days to define the early biological events that drive synovial environment-dependent healing responses. RESULTS: Uninjured intrasynovial tendons were avascular, contained high levels of proteoglycans, and expressed inflammatory factors, complement proteins, and glycolytic enzymes. In contrast, extrasynovial tendons were well vascularized, contained low levels of proteoglycans, and were enriched in inflammation inhibitors and oxidative phosphorylation enzymes. The response to injury and repair was markedly different between the 2 tendon regions. Extrasynovial tendons displayed a robust and rapid neovascularization response, increased expression levels of complement proteins, and an acute shift in metabolism to glycolysis, whereas intrasynovial tendons showed minimal vascularity and muted inflammatory and metabolic responses. CONCLUSIONS: The regional molecular profiles of intact and healing flexor tendons revealed extensive early differences in innate immune response, metabolism, vascularization, and expression of extracellular matrix as a function of the synovial environment. These differences reveal mechanisms through which extrasynovial tendons heal more effectively than do intrasynovial tendons. CLINICAL RELEVANCE: To improve outcomes after operative repair, future treatment strategies should promote features of extrasynovial healing, such as enhanced vascularization and modulation of the complement system and/or glucose metabolism.
Subject(s)
Tendon Injuries , Tendons/physiology , Wound Healing/physiology , Animals , Complement System Proteins/analysis , Dogs , Extracellular Matrix Proteins/analysis , Female , Forelimb , Gene Expression Profiling , Glycolysis , Inflammation Mediators/analysis , Models, Animal , Neovascularization, Physiologic , Oxidative Phosphorylation , Proteoglycans/analysis , Random Allocation , Synovial Membrane , Tendon Injuries/genetics , Tendon Injuries/metabolism , Tendon Injuries/pathology , Tendon Injuries/surgery , Tendons/blood supply , Tendons/metabolism , Tendons/pathology , Time FactorsABSTRACT
Protein tyrosine phosphatase receptor σ (PTPσ) is highly expressed by murine and human hematopoietic stem cells (HSCs) and negatively regulates HSC self-renewal and regeneration. Previous studies of the nervous system suggest that heparan sulfate proteoglycans can inactivate PTPσ by clustering PTPσ receptors on neurons, but this finding has yet to be visually verified with adequate resolution. Here, we sought to visualize and quantify how heparan sulfate proteoglycans regulate the organization and activation of PTPσ in hematopoietic stem/progenitor cells (HSPCs). Our study illustrates that syndecan-2 promotes PTPσ clustering, which sustains phospho-tyrosine and phospho-ezrin levels in association with augmentation of hematopoietic colony formation. Strategies that promote clustering of PTPσ on HSPCs may serve to powerfully augment hematopoietic function.