Non-collagenous Proteins Research Articles

Sensitivity of the amide I band to matrix manipulation in bone: a Raman micro-spectroscopy and spatially offset Raman spectroscopy study.

The fracture resistance of bone arises from the hierarchical arrangement of minerals, collagen fibrils (i.e., cross-linked triple helices of α1 and α2 collagen I chains), non-collagenous proteins, and water. Raman spectroscopy (RS) is not only sensitive to the relative fractions of these constituents, but also to the secondary structure of bone proteins. To assess the ability of RS to detect differences in the protein structure, we quantified the effect of sequentially autoclaving (AC) human cortical bone at 100 °C (∼34.47 kPa) and then at 120 °C (∼117.21 kPa) on the amide I band using a commercial Raman micro-spectroscopy (μRS) instrument and custom spatially offset RS (SORS) instrument in which rings of collection fiber optics are offset from the central excitation fiber optics within a hand-held, cylindrical probe. Being clinically viable, measurements by SORS involved collecting Raman spectra of cadaveric femur mid-shafts (5 male & 5 female donors) through layers of a tissue mimic. Otherwise, μRS and SORS measurements were acquired directly from each bone. AC-related changes in the helical status of collagen I were assessed using amide I sub-peak ratios (intensity, I, at ∼1670 cm-1 relative to intensities at ∼1610 cm-1 and ∼1640 cm-1). The autoclaving manipulation significantly decreased the selected amide I sub-peak ratios as well as shifted peaks at ∼1605 cm-1 (μRS), ∼1636 cm-1 (SORS) and ∼1667 cm-1 in both μRS and SORS. Compared to μRS, SORS detected more significant differences in the amide I sub-peak ratios when the fiber optic probe was directly applied to bone. SORS also detected AC-related decreases in I1670/I1610 and I1670/I1640 when spectra were acquired through layers of the tissue mimic with a thickness ≤2 mm by the 7 mm offset ring, but not with the 5 mm or 6 mm offset ring. Overall, the SORS instrument was more sensitive than the conventional μRS instrument to pressure- and temperature-related changes in the organic matrix that affect the fracture resistance of bone, but SORS analysis of the amide I band is limited to an overlying thickness layer of 2 mm.

Proteins and Our Past: An Exploration of Human Bone Protein from the Eighteenth-Century Fortress of Louisbourg, Nova Scotia, and Its Potential Applications in Bioarchaeological Research

Bioarchaeologists can further investigate human bone metabolism at the biomolecular level by incorporating biochemical methods into their research. Recently, there has been a focus on osteocalcin, an abundant non-collagenous bone protein, because of its clinically identified relationship with biological factors (i.e., age and sex), activity, and pathological conditions (i.e., disease). For this study, osteocalcin was extracted and quantified from the femora of 27 individuals from the Fortress of Louisbourg (1713–1758) skeletal collection to explore if the clinical relationship between osteocalcin and sex, age, activity, and pathological conditions can also be established in archaeological bone. However, no significant relationships between osteocalcin concentrations and biological factors (i.e., age and sex), activity, or pathological conditions were identified. This is the first study to quantify osteocalcin from archaeological human skeletal remains from a Canadian context and provides another example of how this method may be used to study stress in bioarchaeological populations.

Editorial introductions.

Editorial introductions.

Combined Application of Dentin Noncollagenous Proteins and Odontogenic Biphasic Calcium Phosphate in Rabbit Maxillary Sinus Lifting.

Teeth can be used as a raw material for preparing bone substitutes due to their similar chemical composition to bone. The objective of our study was to evaluate the effect of odontogenic biphasic calcium phosphate (BCP) incorporating dentin noncollagenous proteins (DNCPs) on osteogenesis and stability in maxillary sinus augmentation. The composition, structure and morphology of the odontogenic BCP were tested by X-ray powder diffraction (XRD), Brunauer-Emmett-Teller, and scanning electron microscopy methods. The biocompatibility and osteoinduction of DNCPs and materials were examined in vitro and their bone regeneration capacity was verified in vivo. The results showed that the cells adhered and proliferated well on the DNCP-loaded BCP scaffold. The odontogenic BCP and DNCPs promoted osteogenic differentiation of cells, The new bone formation in the BCP groups and DNCP subgroups was significantly higher than the new bone formation in the control, and the new bone quality was better. The bone regeneration effect of odontogenic BCP was similar to the effect of deproteinized bovine bone mineral, but β-TCP did not maintain the height and volume of bone reconstruction. In conclusion, the combined application of DNCPs and odontogenic BCP is an effective strategy for tissue engineering osteogenesis in the maxillary sinus region. The biomimetic strategy could provide a new approach for patients requiring maxillary sinus lifting.

Npp1 prevents external tooth root resorption by regulation of cervical cementum integrity

Tooth roots embedded in the alveolar bone do not typically undergo resorption while the bone continues remodeling in its physiological state. In this study, we analyzed genetically modified mice with the functional inactivation of nucleotide pyrophosphatase 1 (Npp1), encoded by ectonucleotide pyrophosphatase/phosphodiesterase 1 (Enpp1). This mutation leads to the formation of ectopic cervical cementum vulnerable to external tooth root resorption. Cementoblasts with the inactivation of Enpp1 extensively expressed non-collagenous matrix proteins enriched with bone sialoprotein (Bsp), dentin matrix protein 1 (Dmp1), and osteopontin (Opn), which have roles in mineralization through nucleation and in cell adhesion through the Arg-Gly-Asp (RGD) motif. In cementoblasts with the inactivation of Enpp1, β-catenin was significantly activated and induced the expression of these non-collagenous matrix proteins. In addition, adenosine triphosphate (ATP), which is the most preferred substrate of Npp1, accumulated extracellularly and autocrinally induced the expression of the receptor activator of nuclear factor κB ligand (Rankl) in cementoblasts with inactivated Npp1. Consequently, these results strongly suggest that functional Npp1 preserves cervical cementum integrity and supports the anti-resorptive properties of tooth roots through ATP homeostasis in the physiological state of cervical cementum.

The clinical significance of osteopontin on the cardiovascular outcomes in patients with stable coronary artery disease

Osteopontin (OPN) is a noncollagenous matricellular protein which is mainly present in bone matrix. A high OPN level has been associated with heart failure and acute coronary syndrome, however data on patients with chronic coronary syndrome (CCS) are lacking. The present study aimed to evaluate the association between OPN and the prognosis of Taiwanese patients with CCS. We enrolled participants from the Biosignature Registry, a nationwide prospective cohort study conducted at nine different medical centers throughout Taiwan. The inclusion criteria were participants who had received successful percutaneous coronary intervention at least once previously, and stable under medical therapy for at least 1 month before enrollment. They were followed for at least 72 months. Logistic regression and Cox proportional hazard model were used to investigate the association between OPN and clinical outcomes. The outcomes of this study were the first occurrence of hard cardiovascular events and composite cardiovascular outcomes including cardiovascular mortality, revascularization, hospitalization for acute myocardial infarction (AMI) or heart failure. A total of 666 patients with both hs-CRP and osteopontin measurements were enrolled and followed for 72 months. OPN was correlated positively with AMI-related hospitalization, where the highest tertile (Tertile 3) of baseline OPN had the highest risk of AMI-related hospitalization, which remained significant after multivariate adjustments (HR 3.20, p=0.017). In contrast, combining OPN and hs-CRP did not improve the prediction of CV outcomes. OPN may be a potentially valuable biomarker in predicting CV outcomes. During 6 years of follow-up period, an OPN level >4810pg/ml was associated with a significantly higher incidence of AMI-related hospitalization in CCS patients who received successful PCI before the enrollment.

Albumin-Coated Polycaprolactone (PCL)-Decellularized Extracellular Matrix (dECM) Scaffold for Bone Regeneration.

With the emphasis on collagen and hydroxyapatite, the main structural components of bone tissue, synthetic grafts fall short of matching the clinical efficacy of autologous bone grafts. Excluded non-collagenous protein (NCPs) and carbohydrates also participate in critical cell signaling cascades and guide mineral deposition during intermediate stages of bone healing. By mimicking the native fracture repair process, polymeric scaffolds that incorporate calcium-binding moieties present in fibrocartilage can potentially enhance their bioactivity, mineralization, and bone growth. Likewise, coating polymeric fibers with serum albumin is an additional strategy that can impart collagen-like biofunctionality and further increase mineral deposition on the fibrous surface. Here, a combination of electrospun polycaprolactone (PCL) fibers with chondrocyte-derived decellularized extracellular matrix (dECM) and albumin coating were investigated as a fibrocartilage-mimetic scaffold that can serve as a woven bone precursor for bone regeneration. PCL fibrous constructs coated with dECM and albumin are shown to synergistically increase calcium concentration and calcium phosphate (CaP) deposition in a simulated body fluid biomineralization assay. Albumin/dECM coating increased osteoblast proliferation and mineral deposition in culture. In contrast, CaP coating transformed osteoblast bone lining morphology into cuboidal phenotype and arrested their proliferation. Cell sheets of osteoblasts cultured on dECM/albumin/CaP-coated constructs exhibited an increase in calcium deposition and secretion of collagen, osteopontin, osteocalcin, and bone morphogenetic protein. These results highlight the potential of biomolecular coatings to enhance bone-mimetic properties of synthetic nanofibrous scaffolds, stimulate critical protein and mineral deposition, and augment the bone's capacity to heal. Thus, mimicking the intermediate stages of bone regeneration by incorporating calcium-binding moieties may prove to be a useful strategy for improving the clinical outcomes of synthetic bone grafts.

Suffruticosol B Is an Osteogenic Inducer through Osteoblast Differentiation, Autophagy, Adhesion, and Migration.

Suffruticosol B (Suf-B) is a stilbene found in Paeonia suffruticosa ANDR., which has been traditionally used in medicine. Stilbenes and their derivatives possess various pharmacological effects, such as anticancer, anti-inflammatory, and anti-osteoporotic activities. This study aimed to explore the bone-forming activities and mechanisms of Suf-B in pre-osteoblasts. Herein, >99.9% pure Suf-B was isolated from P. suffruticosa methanolic extracts. High concentrations of Suf-B were cytotoxic, whereas low concentrations did not affect cytotoxicity in pre-osteoblasts. Under zero levels of cytotoxicity, Suf-B exhibited bone-forming abilities by enhancing alkaline phosphatase enzyme activities, bone matrix calcification, and expression levels with non-collagenous proteins. Suf-B induces intracellular signal transduction, leading to nuclear RUNX2 expression. Suf-B-stimulated differentiation showed increases in autophagy proteins and autophagosomes, as well as enhancement of osteoblast adhesion and transmigration on the ECM. These results indicate that Suf-B has osteogenic qualities related to differentiation, autophagy, adhesion, and migration. This also suggests that Suf-B could have a therapeutic effect as a phytomedicine in skeletal disorders.

Characterization of bioactive substances involved in the induction of bone augmentation using demineralized bone sheets

PurposeTo investigate the bone augmentation ability of demineralized bone sheets mixed with allogeneic bone with protein fractions containing bioactive substances and the interaction between coexisting bioactive substances and proteins.MethodsFour types of demineralized bone sheets mixed with allogeneic bone in the presence or absence of bone proteins were created. Transplantation experiments using each demineralized bone sheet were performed in rats, and their ability to induce bone augmentation was analysed by microcomputed tomography images. Bioactive substances in bone proteins were isolated by heparin affinity chromatography and detected by the measurement of alkaline phosphatase activity in human periodontal ligament cells and dual luciferase assays. Noncollagenous proteins (NCPs) coexisting with the bioactive substances were identified by mass spectrometry, and their interaction with bioactive substances was investigated by in vitro binding experiments.ResultsDemineralized bone sheets containing bone proteins possessed the ability to induce bone augmentation. Bone proteins were isolated into five fractions by heparin affinity chromatography, and transforming growth factor-beta (TGF-β) was detected in the third fraction (Hep-c). Dentin matrix protein 1 (DMP1), matrix extracellular phosphoglycoprotein (MEPE), and biglycan (BGN) also coexisted in Hep-c, and the binding of these proteins to TGF-β increased TGF-β activity by approximately 14.7% to 32.7%.ConclusionsDemineralized bone sheets are capable of inducing bone augmentation, and this ability is mainly due to TGF-β in the bone protein mixed with the sheets. The activity of TGF-β is maintained when binding to bone NCPs such as DMP1, MEPE, and BGN in the sheets.

Water flow through bone: Neutron tomography reveals differences in water permeability between osteocytic and anosteocytic bone material

Vertebrate bones are made of a nanocomposite consisting of water, mineral and organics. Water helps bone material withstand mechanical stress and participates in sensation of external loads. Water diffusion across vertebrae of medaka (bone material lacking osteocytes) and zebrafish (bone material containing osteocytes) was compared using neutron tomography. Samples were measured both wet and following immersion in deuterated-water (D2O). By quantifying H+ exchange and mutual alignment with X-ray µCT scans, the amount of water expelled from complete vertebra was determined. The findings revealed that anosteocytic bone material is almost twice as amenable to D2O diffusion and H2O exchange, and that unexpectedly, far more water is retained in osteocytic zebrafish bone. Diffusion in osteocytic bones (only 33 % – 39 % water expelled) is therefore restricted as compared to anosteocytic bone (∼ 60 % of water expelled), presumably because water flow is confined to the lacunar-canalicular network (LCN) open-pore system. Histology and Raman spectroscopy showed that anosteocytic bone contains less proteoglycans than osteocytic bone. These findings identify a previously unknown functional difference between the two bone materials. Therefore, this study proposes that osteocytic bone retains water, aided by non-collagenous proteins, which contribute to its poroelastic mechano-transduction of water flow confined inside the LCN porosity.

Nuclear Magnetic Resonance and Metadynamics Simulations Reveal the Atomistic Binding of l-Serine and O-Phospho-l-Serine at Disordered Calcium Phosphate Surfaces of Biocements

Interactions between biomolecules and structurally disordered calcium phosphate (CaP) surfaces are crucial for the regulation of bone mineralization by noncollagenous proteins, the organization of complexes of casein and amorphous calcium phosphate (ACP) in milk, as well as for structure–function relationships of hybrid organic/inorganic interfaces in biomaterials. By a combination of advanced solid-state NMR experiments and metadynamics simulations, we examine the detailed binding of O-phospho-l-serine (Pser) and l-serine (Ser) with ACP in bone-adhesive CaP cements, whose capacity of gluing fractured bone together stems from the close integration of the organic molecules with ACP over a subnanometer scale. The proximity of each carboxy, aliphatic, and amino group of Pser/Ser to the Ca2+ and phosphate species of ACP observed from the metadynamics-derived models agreed well with results from heteronuclear solid-state NMR experiments that are sensitive to the 13C–31P and 15N–31P distances. The inorganic/organic contacts in Pser-doped cements are also contrasted with experimental and modeled data on the Pser binding at nanocrystalline HA particles grown from a Pser-bearing aqueous solution. The molecular adsorption is driven mainly by electrostatic interactions between the negatively charged carboxy/phosphate groups and Ca2+ cations of ACP, along with H bonds to either protonated or nonprotonated inorganic phosphate groups. The Pser and Ser molecules anchor at their phosphate/amino and carboxy/amino moieties, respectively, leading to an extended molecular conformation across the surface, as opposed to an “upright standing” molecule that would result from the binding of one sole functional group.

The Correlation between Total Alkaline Phosphatase and Osteocalcin Levels in Systemic Lupus Erythematosus Patients

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune inflammatory disease with various complications, including osteoporosis. However, Bone Mineral Density (BMD) examination, a gold standard for diagnosing and monitoring osteoporosis, is static. Alkaline phosphatase (ALP) is a membrane-bound glycoprotein that catalysis the hydrolysis of monoester phosphate. Osteocalcin (OC) is a non-collagenic bone protein that binds calcium and phosphate, which are both dynamic bone formation activity markers. This study analyzes the correlation between total ALP and OC serum levels in SLE patients. A cross-sectional observational analytic study was conducted in the Clinical Pathology Installation of Dr. Moewardi Hospital Surakarta in June 2020. The subjects were SLE patients receiving Methylprednisolone (MEP) therapy ≥1 year. Data distribution normality test by Saphiro-Wilk, comparative analysis with unpaired T-test, degree of correlation strength between research variables by Pearson correlation test. There were 41 female subjects, and comparative analysis of total ALP and serum OC levels were not significantly different in inactive and active SLE (ALP p=0.373, serum OC p=0.700). Total ALP and serum OC was found to have a weak positive correlation in all SLE patients (r=0.337; p=0.031), a moderate positive correlation in active SLE (r=0.426; p=0.043), while in inactive SLE there was no significant correlation (r=0.247; p=0.324). There is a significant moderate positive correlation between total ALP and serum OC in SLE patients. Total ALP and serum OC examinations are necessary for osteoporosis screening in SLE patients with > 1-year glucocorticoid (GC) therapy.

Dentin Sialoprotein/Phosphophoryn (DSP/PP) as Bio-Inductive Materials for Direct Pulp Capping.

Conventional direct pulp capping, such as calcium hydroxide (Ca(OH)2) or silicate products, usually induces an inflammatory reaction to provoke pulp regeneration. Phosphophoryn (PP) and dentin sialoprotein (DSP), the two most abundant non-collagenous proteins in the dentin matrix, are responsible for dentin mineralization, pulp cell migration, and differentiation. Here we examined the PP and combined DSP/PP as bio-inductive pulp capping materials by in vitro and in vivo tests. Firstly, the effects of the PP dose on pulp cell migration and matrix protein expression were examined by an agarose bead test. Secondly, the role of recombinant DSP (recDSP) and recDSP/PP on stimulating DSP-PP transcript expression was examined by RT-PCR. DSPP mRNA was also knocked down by RNA interference (RNAi) to examine their functions on dentin matrix mineralization. Finally, we used ferret animal models to test PP and recDSP/PP acting as capping agents on in vivo pulp responses and reparative dentin formation. The result showed that intermediate-dose PP was the most effective to enhance cell migration and differentiation. RecDSP/PP strongly enhanced the DSP-PP transcript expression, while inhibition of DSPP mRNA expression by siRNAs partially or completely affected dental pulp cell mineralization. The in vivo results showed that intermediate-dose PP and recDSP/PP proteins induced less pulp inflammation and promoted reparative dentin formation. Contrarily, conventional calcium hydroxide induced severe pulp inflammation. With these findings, DSP and PP could serve as capping agents for pulp capping therapy.

Insight on the Role of Poly(acrylic acid) for Directing Calcium Phosphate Mineralization of Synthetic Polymer Bone Scaffolds.

Bone is a complex tissue with robust mechanical and biological properties originating from its nanoscale composite structure. Although much research has been conducted on designing bioinspired artificial bone, the role of biological macromolecules such as noncollagenous proteins (NCPs) in influencing the formation of biominerals is not fully understood. In this work, we have designed nanofiber shish-kebab (NFSK) structures that can template mineral location by recruiting calcium cations from an ion-rich mineralization solution. Poly(acrylic acid) (PAA) is used as the NCP analogue to understand the role of polyelectrolytes in scaffold mineralization. We demonstrate that the addition of PAA in the mineralization solution suppresses the development of extrafibrillar minerals as well as slows down the accumulation and development of mineral phases within NFSKs. We probe the mechanism behind this effect by monitoring the free calcium ion concentration, investigating the PAA molecular weight effect, and conducting mineralization in membrane-partitioned solutions. Our results suggest the 2-fold effect of PAA as a solution stabilizer and physical barrier on the NFSK surface. This work could shed light on the understanding of the NCP effect in biomineralization.

Effects of Different Acetic Acid Immersion Time on the Properties of Collagen from Pangasius Skin

Highlight Research Experimental use of pre-treated pangasius skin as collagen raw material using different acetic acid immersion time Effects of immersion time on the yield of collagen from pangasius skin Effects of immersion time on the proximate content of collagen from pangasius skin Presenting SDS-Page profile of collagen from pangasius skin Abstract Pangasius sp. production in Indonesia has reached 384,310 tons in 2019. One of the main waste in pangasius fillet industry is the skin, which reached to 6% of body mass. Fish skins are alternative for making collagen because it has no restrictions for certain religions and ethnicities. Collagen is a protein biomaterial which acts as the main component of connective tissue. Extracting collagen using organic acids such as acetic acid is the most common extraction method. Herein, we report the effects of different immersion time of acetic acid to collagen properties from pangasius skin. In this study, pangasius skin was treated using 10% alcohol with the ratio 1:10 (w/v) for defatting and 0.1M NaOH with the ratio 1:10 (w/v) for eliminating non-collagenous protein. The immersion of 0.5M acetic acid was carried out on pangasius skin with the ratio of 1:20 (w/v), for 24, 48, and 72h at temperature less than 15oC. The sample was salted-out for 24 hours with NaCl until the concentration reached 2.5M, then the sample was freeze-dried at -40oC. This study investigated that longer immersion time affected the properties of pangasius skin collagen. Different immersion time significantly affected the yield of collagen from pangasius skin (p<0.05). Pangasius skin has a potential to be used as collagen raw material, and 72h of immersion time (P3) is suggested to produce pangasius skin collagen with the highest yield and protein content (6.15 % and 9.26 %). Production of collagen from the fish skin will contribute to increase pangasius waste valorization in pharmaceutical industry.

Bioinspired Silk Fibroin Mineralization for Advanced In Vitro Bone Remodeling Models

AbstractHuman in vitro bone models can create the possibility for investigation of physiological bone remodeling while addressing the principle of replacement, reduction and refinement of animal experiments (3R). Current in vitro models lack cell–matrix interactions and their spatiotemporal complexity. To facilitate these analyses, a bone‐mimetic template is developed in this study, inspired by bone's extracellular matrix composition and organization. Silk fibroin (SF) is used as an organic matrix, poly‐aspartic acid (pAsp) is used to mimic the functionality of noncollagenous proteins, and 10× simulated body fluid serves as mineralization solution. By using pAsp in the mineralization solution, minerals are guided toward the SF material resulting in mineralization inside and as a coating on top of the SF. After cytocompatibility testing, remodeling experiments are performed in which mineralized scaffold remodeling by osteoclasts and osteoblasts is tracked with nondestructive microcomputed tomography and medium analyses over a period of 42 d. The mineralized scaffolds support osteoclastic resorption and osteoblastic mineralization, in the physiological bone remodeling specific sequence. This model could therefore facilitate the investigation of cell–matrix interactions and may thus reduce animal experiments and advance in vitro drug testing for bone remodeling pathologies like osteoporosis, where cell–matrix interactions need to be targeted.

Characterization of SIBLING Proteins in the Mineralized Tissues.

The SIBLING proteins are a family of non-collagenous proteins (NCPs) previously thought to be expressed only in dentin but have been demonstrated in other mineralized and non-mineralized tissues. They are believed to play vital roles in both osteogenesis and dentinogenesis. Since they are tightly regulated lifelong processes and involve a peak of mineralization, three different age groups were investigated. Fifteen wild-type (WT) mice were euthanized at ages 1, 3, and 6 months. Hematoxylin and eosin staining (H&E) was performed to localize various microscopic structures in the mice mandibles and tibias. The immunostaining pattern was compared using antibodies for dentin sialoprotein (DSP), dentin matrix protein 1 (DMP1), bone sialoprotein (BSP), and osteopontin (OPN). Immunostaining of DSP in tibia showed its most noticeable staining in the 3-month age group. DSP was expressed in alveolar bone, cellular cementum, and PDL. A similar expression of DMP1 was seen in the tibia and dentin. BSP was most noticeably detected in the tibia and acellular cementum. OPN was mainly expressed in the bone. A lower level of OPN was observed at all age groups in the teeth. The immunostaining intensity was the least detected for all proteins in the 6-month tibia sample. The expression patterns of the four SIBLING proteins showed variations in their staining intensity and temporospatial patterning concordant with skeletal and dental maturity. These findings suggest some role in this tightly regulated mineralization process.

The role of osteocalcin in regulation of glycolipid metabolism and muscle function in children with osteogenesis imperfecta.

ObjectiveOsteoblasts are discovered to secrete hormones with endocrine effects on metabolism, and osteocalcin (OC) is the most abundant non-collagenous protein in bone. We investigate the relationship between serum OC levels and glycolipid metabolism and muscle function in children with osteogenesis imperfecta (OI).MethodsA total of 225 children with OI and 80 healthy controls matched in age and gender were included in this single center study. Serum levels of fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), low- and high-density lipoprotein cholesterol (LDL-C, HDL-C) were measured by automated analyzers. Serum levels of fasting insulin (FINS) were measured using an automated electrochemiluminescence system. Serum levels of OC and undercarboxylated osteocalcin (ucOC) were measured by enzyme-linked immunosorbent assay. Grip strength and timed-up-and-go (TUG) test were measured. Bone mineral density (BMD) and body composition were measured using dual-energy X-ray absorptiometry.ResultsOI patients had significantly higher body mass index (BMI), FBG, and HOMA-IR, but lower HDL-C levels, lower grip strength and longer TUG than control group (all P<0.05). Serum OC, ucOC levels, and ucOC/OC in OI type III patients were significantly lower than those in OI patients with type I and IV. Serum levels of OC, ucOC, and ucOC/OC were negatively correlated to BMI, FBG, insulin levels, and HOMA-IR (all P<0.05). The ratio of ucOC/OC was positively correlated to grip strength (r=0.512, P=0.036), lean mass percentage (%LM) of the total body and limbs, and negatively correlated to fat mass percentage (%FM) of the total body, %FM and fat mass index (FMI) of the trunk (all P<0.05).ConclusionsObesity, glucolipid metabolic abnormalities, and reduced grip strength were common in children with OI. Circulating osteocalcin and ucOC may play an important role in the regulation of glucose metabolism, as well as the muscle function of children with OI.

Tenogenic induction of human adipose-derived stem cells by soluble tendon extracellular matrix: composition and transcriptomic analyses

BackgroundTendon healing is clinically challenging largely due to its inferior regenerative capacity. We have previously prepared a soluble, DNA-free, urea-extracted bovine tendon-derived extracellular matrix (tECM) that exhibits strong pro-tenogenic bioactivity on human adipose-derived stem cells (hASCs). In this study, we aimed to elucidate the mechanism of tECM bioactivity via characterization of tECM protein composition and comparison of transcriptomic profiles of hASC cultures treated with tECM versus collagen type I (Col1) as a control ECM component.MethodsThe protein composition of tECM was characterized by SDS-PAGE, hydroxyproline assay, and proteomics analysis. To investigate tECM pro-tenogenic bioactivity and mechanism of action, differentiation of tECM-treated hASC cultures was compared to serum control medium or Col1-treated groups, as assessed via immunofluorescence for tenogenic markers and RNA Sequencing (RNA-Seq).ResultsUrea-extracted tECM yielded consistent protein composition, including collagens (20% w/w) and at least 17 non-collagenous proteins (< 100 kDa) based on MS analysis. Compared to current literature, tECM included key tendon ECM components that are functionally involved in tendon regeneration, as well as those that are involved in similar principal Gene Ontology (GO) functions (ECM-receptor interaction and collagen formation) and signaling pathways (ECM-receptor interaction and focal adhesion). When used as a cell culture supplement, tECM enhanced hASC proliferation and tenogenic differentiation compared to the Col1 and FBS treatment groups based on immunostaining of tenogenesis-associated markers. Furthermore, RNA-Seq analysis revealed a total of 584 genes differentially expressed among the three culture groups. Specifically, Col1-treated hASCs predominantly exhibited expression of genes and pathways related to ECM-associated processes, while tECM-treated hASCs expressed a mixture of ECM- and cell activity-associated processes, which may explain in part the enhanced proliferation and tenogenic differentiation of tECM-treated hASCs.ConclusionsOur findings showed that urea-extracted tECM contained 20% w/w collagens and is significantly enriched with other non-collagenous tendon ECM components. Compared to Col1 treatment, tECM supplementation enhanced hASC proliferation and tenogenic differentiation as well as induced distinct gene expression profiles. These findings provide insights into the potential mechanism of the pro-tenogenic bioactivity of tECM and support the development of future tECM-based approaches for tendon repair.

IR-SPECTROSCOPIC ANALYSIS OF HARD TISSUES OF LOWER WISDOM TEETH AT THE STAGE OF CONNECTIVE TISSUE DYSPLASIA

We carry out the spectral analysis of enamel, enamel-dentin junction, and dentin of human teeth at the stage of connective tissue dysplasia and without it. It is established that in the case of connective tissue dysplasia in the hard tissues of teeth there is a clear heterogeneity of spectra. In the group with connective tissue dysplasia the maximum changes of IR spectra are observed in collagen and non-collagen proteins of the organic matrix of enamel and dentin. For the group without connective tissue dysplasia the greater uniformity is observed in dentin. The biochemical abnormalities detected in the dentin of the lower “wisdom” teeth can be explained by dysplastic collagen formation disorders in the dental hard tissues, which leads to marked shifts in the enamel layer under the aggressive action of the oral fluid. In the group without connective tissue dysplasia the imbalance in the structure of the protein matrix of tooth enamel is related only to the mineralizing effect of the oral fluid on it.