Bone collagen hydrolysates(peptides)derived from byproduct of animal product processing have been used to produce commercially valuable products due to their potential antioxidant activity.Maillard glycosylated reacti...Bone collagen hydrolysates(peptides)derived from byproduct of animal product processing have been used to produce commercially valuable products due to their potential antioxidant activity.Maillard glycosylated reaction is considered as a promising method to enhance the antioxidant activity of peptides.Hence,this research aims at investigating the Maillard glycosylation activity and antioxidant activity of bone collagen hydrolysates from different sources.In this study,3 glycosylated bone collagen hydrolysates were prepared and characterized,and cytotoxicity and antioxidant activity were analyzed and evaluated.The free amino groups loss,browning intensity,and fluorescence intensity of G-Cbcp(glycosylated chicken bone collagen hydrolysates(peptides))were the heaviest,followed by G-Pbcp(glycosylated porcine bone collagen hydrolysates(peptides))and G-Bbcp(glycosylated bovine bone collagen hydrolysates(peptides)).The results of amino acid analysis showed that amino acid composition of different bone collagen hydrolysates was significantly different and the amino acid decreased to different degrees after Maillard glycosylated reaction,which may lead to differences in Maillard glycosylated reaction activity.Furthermore,the 3 glycosylated hydrolysates showed no significant cytotoxicity.The results showed that glycosylation process significantly increased the antioxidant activity of bone collagen hydrolysates,and G-Cbcp showed the strongest antioxidant activity,followed by G-Pbcp and G-Bbcp.Therefore,compared with the bone collagen hydrolysates,3 glycosylated hydrolysates showed significant characteristic and structural changes,and higher antioxidant activity.展开更多
This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instan...This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.展开更多
Age and diabetes have long been known to induce an oxidative reaction between glucose and collagen,leading to the accumulation of advanced glycation end-products(AGEs)cross-links in collagenous tissues.More recently,A...Age and diabetes have long been known to induce an oxidative reaction between glucose and collagen,leading to the accumulation of advanced glycation end-products(AGEs)cross-links in collagenous tissues.More recently,AGEs content has been related to loss of bone quality,independent of bone mass,and increased fracture risk with aging and diabetes.Loss of bone quality is mostly attributed to changes in material properties,structural organization,or cellular remodeling.Though all these factors play a role in bone fragility disease,some common recurring patterns can be found between diabetic and age-related bone fragility.The main pattern we will discuss in this viewpoint is the increase of fibrillar collagen stiffness and loss of collagen-induced plasticity with AGE accumulation.This study focused on recent related experimental studies and discusses the correlation between fluorescent AGEs content at the molecular and fibrillar scales,collagen deformation mechanisms at the nanoscale,and resistance to bone fracture at the macroscale.展开更多
In this study, yak bone collagen hydrolysate(YBCH)was produced by mixed proteases and provided to standard-diet mice at a different dose(low dose(LD), medium dose(MD), and high dose(HD))to investigate its effects on t...In this study, yak bone collagen hydrolysate(YBCH)was produced by mixed proteases and provided to standard-diet mice at a different dose(low dose(LD), medium dose(MD), and high dose(HD))to investigate its effects on the composition of gut microbiota and short-chain fatty acids(SCFA)production. It was found that YBCH was mainly composed of small molecular peptides whose molecular weight below 2 000 Da. Notably, supplementation with different doses of YBCH could significantly downregulate the ratio of Firmicutes to Bacteroidetes in the fecal microbiota. At the family level, the Lachnospiraceae abundance was significantly reduced in the YBCH gavage groups(mean reduction ratio 41.7 %, 35.2%, and 36.4% for LD, MD, and HD group, respectively). The predicted functions of gut microbes in the MD group were significantly increased at “lipid metabolism” and “glycan biosynthesis and metabolism”. Moreover, the SCFA production in the YBCH groups was elevated. Especially, the concentration of acetic acid, propionic acid, and butyric acid in the MD group was separately increased 79.7%, 89.2%, and 78.8% than that in the NC group. These results indicated that YBCH might be applied in the development of functional food for intestinal microecological regulation.展开更多
This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. ...This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. Fifty-four （54） rats were studied. A circular bony defect （8 mm diameter） was formed in the centre of the calvaria using a trephine bur. The CFB-HAP membrane was prepared by thermally induced phase separation. In the experimental group （n= 18）, the CFB-HAP membrane was used to cover the bony defect, and in the control group （n= 18）, a resorbable collagen membrane （Bio-Gide） was used. In the negative control group （n= 18）, no membrane was used. In each group, six animals were euthanized at 2, 4 and 8 weeks after surgery. The specimens were then analysed using micro-CT. There were significant differences in bone volume （BV） and bone mineral density （BMD） （P〈O.05） between the negative control group and the membrane groups. However, there were no significant differences between the CFB-HAP group and the collagen group. We concluded that the CFB-HAP membrane has significant potential as a guided bone regeneration （GBR） membrane.展开更多
Ovine bones are the major by-products after slaughtered. The present study was conducted to extract and characterize acid soluble collagens （ASC） and pepsin soluble collagens （PSC） from ovine bones （Ujumuqin shee...Ovine bones are the major by-products after slaughtered. The present study was conducted to extract and characterize acid soluble collagens （ASC） and pepsin soluble collagens （PSC） from ovine bones （Ujumuqin sheep）. Ovine bones collagen were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE） and liquid chromatography-tan- dem mass spectrometry （LC-MS/MS） as type I collagen. The results of Fourier transform infrared （FTIR） spectra analysis testified the existence of triple superhelical structure in both ASC and PSC, showing pepsin did not disrupt the triple helical structure of ovine bones collagen. Glycine, accounting for one-third of total amino acids, was the major amino acid for ovine bones collagen. Higher imino acid content was responsible for higher thermal denaturation temperature of ovine bones collagen compared to fish collagens. The isoelectric point of ASC was lower than PSC due to the higher content of acidic amino acids. Therefore, this study provides the potential reference for collagen extraction and application of ovine bones by-procduct.展开更多
Combinations of biomaterials and cells can effectively target delivery of cells or other therapeutic factors to the brain to rebuild damaged nerve pathways after brain injury.Porous collagen-chitosan scaffolds were pr...Combinations of biomaterials and cells can effectively target delivery of cells or other therapeutic factors to the brain to rebuild damaged nerve pathways after brain injury.Porous collagen-chitosan scaffolds were prepared by a freeze-drying method based on brain tissue engineering.The scaffolds were impregnated with rat bone marrow mesenchymal stem cells.A traumatic brain injury rat model was established using the 300 g weight free fall impact method.Bone marrow mesenchymal stem cells/collagen-chitosan scaffolds were implanted into the injured brain.Modified neurological severity scores were used to assess the recovery of neurological function.The Morris water maze was employed to determine spatial learning and memory abilities.Hematoxylin-eosin staining was performed to measure pathological changes in brain tissue.Immunohistochemistry was performed for vascular endothelial growth factor and for 5-bromo-2-deoxyuridine(BrdU)/neuron specific enolase and BrdU/glial fibrillary acidic protein.Our results demonstrated that the transplantation of bone marrow mesenchymal stem cells and collagen-chitosan scaffolds to traumatic brain injury rats remarkably reduced modified neurological severity scores,shortened the average latency of the Morris water maze,increased the number of platform crossings,diminished the degeneration of damaged brain tissue,and increased the positive reaction of vascular endothelial growth factor in the transplantation and surrounding areas.At 14 days after transplantation,increased BrdU/glial fibrillary acidic protein expression and decreased BrdU/neuron specific enolase expression were observed in bone marrow mesenchymal stem cells in the injured area.The therapeutic effect of bone marrow mesenchymal stem cells and collagen-chitosan scaffolds was superior to stereotactic injection of bone marrow mesenchymal stem cells alone.To test the biocompatibility and immunogenicity of bone marrow mesenchymal stem cells and collagen-chitosan scaffolds,immunosuppressive cyclosporine was intravenously injected 12 hours before transplantation and 1-5 days after transplantation.The above indicators were similar to those of rats treated with bone marrow mesenchymal stem cells and collagen-chitosan scaffolds only.These findings indicate that transplantation of bone marrow mesenchymal stem cells in a collagen-chitosan scaffold can promote the recovery of neuropathological injury in rats with traumatic brain injury.This approach has the potential to be developed as a treatment for traumatic brain injury in humans.All experimental procedures were approved by the Institutional Animal Investigation Committee of Capital Medical University,China(approval No.AEEI-2015-035)in December 2015.展开更多
The aim of the present real time in vivo micro-computed tomography （pCT） and histologic experiment was to assess the efficacy of guided bone regeneration （GBR） around standardized calvarial critical size defects ...The aim of the present real time in vivo micro-computed tomography （pCT） and histologic experiment was to assess the efficacy of guided bone regeneration （GBR） around standardized calvarial critical size defects （CSD） using bone marrow-derived mesenchymal stem cells （BMSCs）, and collagen membrane （CM） with and without tricalcium phosphate （TCP） graft material. In the calvaria of nine female Sprague-Dawley rats, full-thickness CSD （diameter 4.6 mm） were created under general anesthesia. Treatment-wise, rats were divided into three groups. In group 1, CSD was covered with a resorbable CM; in group 2, BMSCs were filled in CSD and covered with CM; and in group 3, TCP soaked in BMSCs was placed in CSD and covered with CM. All defects were closed using resorbable sutures. Bone volume and bone mineral density of newly formed bone （NFB） and remaining TCP particles and rate of new bone formation was determined at baseline, 2, 4, 6, and 10 weeks using in vivo pCT. At the lOth week, the rats were killed and calvarial segments were assessed histologically. The results showed that the hardness of NFB was similar to that of the native bone in groups I and 2 as compared to the NFB in group 3. Likewise, values for the modulus of elasticity were also significantly higher in group 3 compared to groups 1 and 2. This suggests that TCP when used in combination with BMSCs and without CM was unable to form bone of significant strength that could possibly provide mechanical ＂lock＂ between the natural bone and NFB. The use of BMSCs as adjuncts to conventional GBR initiated new bone formation as early as 2 weeks of treatment compared to when GBR is attempted without adiunct BMSC therapy.展开更多
In this study, we successfully constructed a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffold in vitro, transplanted either the composite or bone marrow mesenchymal stem cells alone int...In this study, we successfully constructed a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffold in vitro, transplanted either the composite or bone marrow mesenchymal stem cells alone into the ischemic area in animal models, and compared their effects. At 14 days after co-transplantation of bone marrow mesenchymal stem cells and the hi- tosan-collagen scaffold, neurological function recovered noticeably. Vascular endothelial growth factor expression and nestin-labeled neural precursor cells were detected in the iscbemic area, surrounding tissue, hippocampal dentate gyrus and subventricular zone. Simultaneously, a high level of expression of glial fibrillary acidic protein and a low level of expression of neuron-spe- cific enolase were visible in BrdU-labeled bone marrow mesenchymal stem cells. These findings suggest that transplantation of a composite of bone marrow mesenchymal stem cells and a chi- tosan-collagen scaffold has a neuroprotective effect following ischemic stroke.展开更多
BACKGROUND Collagen is one of the most commonly used natural biomaterials for tendon tissue engineering.One of the possible practical ways to further enhance tendon repair is to combine a porous collagen sponge scaffo...BACKGROUND Collagen is one of the most commonly used natural biomaterials for tendon tissue engineering.One of the possible practical ways to further enhance tendon repair is to combine a porous collagen sponge scaffold with a suitable growth factor or cytokine that has an inherent ability to promote the recruitment,proliferation,and tenogenic differentiation of cells.However,there is an incomplete understanding of which growth factors are sufficient and optimal for the tenogenic differentiation of rat bone marrow mesenchymal stem cells(BMSCs)in a collagen sponge-based 3D culture system.AIM To identify one or more ideal growth factors that benefit the proliferation and tenogenic differentiation of rat BMSCs in a porous collagen sponge scaffold.METHODS We constructed a 3D culture system based on a type I collagen sponge scaffold.The surface topography of the collagen sponge scaffold was observed by scanning electron microscopy.Primary BMSCs were isolated from Sprague-Dawley rats.Cell survival on the surfaces of the scaffolds with different growth factors was assessed by live/dead assay and CCK-8 assay.The mRNA and protein expression levels were confirmed by quantitative real-time polymerase chain reaction and Western blot,respectively.The deposited collagen was assessed by Sirius Red staining.RESULTS Transforming growth factorβ1(TGF-β1)showed great promise in the tenogenic differentiation of BMSCs compared to growth differentiation factor 7(GDF-7)and insulin-like growth factor 1(IGF-1)in both the 2D and 3D cultures,and the 3D culture enhanced the differentiation of BMSCs into tenocytes well beyond the level of induction in the 2D culture after TGF-β1 treatment.In the 2D culture,the proliferation of the BMSCs showed no significant changes compared to the control group after TGF-β1,IGF-1,or GDF-7 treatment.However,TGF-β1 and GDF-7 could increase the cell proliferation in the 3D culture.Strangely,we also found more dead cells in the BMSC-collagen sponge constructs that were treated with TGF-β1.Moreover,TGF-β1 promoted more collagen deposition in both the 2D and 3D cultures.CONCLUSION Collagen sponge-based 3D culture with TGF-β1 enhances the responsiveness of the proliferation and tenogenic differentiation of rat BMSCs.展开更多
BACKGROUND Intracranial and extracranial artery stenosis is associated with cerebral infarction.Vascular calcification and atherosclerosis are the main causes of stenosis and major risk factors for cardiovascular and ...BACKGROUND Intracranial and extracranial artery stenosis is associated with cerebral infarction.Vascular calcification and atherosclerosis are the main causes of stenosis and major risk factors for cardiovascular and cerebrovascular events in patients with type 2 diabetes mellitus(T2DM).Bone turnover biomarkers(BTMs)are associated with vascular calcification,atherosclerosis,glucose,and lipid metabolism.AIM To investigate the association of circulating BTM levels with severe intracranial and extracranial artery stenosis in patients with T2DM.METHODS For this cross-sectional study including 257 T2DM patients,levels of the BTMs serum osteocalcin(OC),C-terminal cross-linked telopeptide of type I collagen(CTX),and procollagen type I N-peptide were measured by electrical chemiluminescent immunoassay,and artery stenosis was assessed by color Doppler and transcranial Doppler.Patients were grouped according to the existence and location(intracranial vs.extracranial)of artery stenosis.Correlations between BTM levels,previous stroke,stenosis location,and glucose and lipid metabolism were analyzed.RESULTS T2DM patients with severe artery stenosis had a higher frequency of previous stroke and levels of all three tested BTMs(all P<0.05)than patients without.Some differences in OC and CTX levels were observed according to the location of artery stenosis.Significant associations were also observed between BTM levels and some glucose and lipid homeostasis parameters.On multivariate logistic regression analysis,all BTMs were significant predictors of artery stenosis in T2DM patients with and without adjustment for confounding factors(all P<0.001),and receiver operating characteristic curve analysis demonstrated the ability of BTM levels to predict artery stenosis in T2DM patients.CONCLUSION BTM levels were found to be independent risk factors for severe intracranial and extracranial artery stenosis and were differentially associated with glucose and lipid metabolism in patients with T2DM.Therefore,BTMs may be promising biomarkers and potential therapeutic targets for artery stenosis.展开更多
A synthetizing material blended with two distinct proteins (collagen and casein) and mineral mixture, was developed in order to evaluate their properties suitable for possible applications in the biomedical such as in...A synthetizing material blended with two distinct proteins (collagen and casein) and mineral mixture, was developed in order to evaluate their properties suitable for possible applications in the biomedical such as inducing the regeneration of damaged bone, either due to an accident or illness. Samples were evaluated by 1) Mechanical properties tests under the bending, 2) Scanning electronic microscopy and 3) Infrared spectroscopy were carried out. The results showed that the developed material has breaking strength and structure characteristics associated with the protein used in their composition. This fact suggests that the used protein determines the resistance of the material, in such a way according to the required use, being able to choose appropriate strength and duration either short or long time. The material composition for specific use, in order to find the most suitable mixture for bone replacement, or induce bone recovery, according to the required properties similar to those of damaged living tissue.展开更多
An insight into the interaction of collagen type I with apatite in bone tissue was performed by using differential scanning calorimetry, Fourier transform infrared spectroscopy, and molecular modeling. Scanning electr...An insight into the interaction of collagen type I with apatite in bone tissue was performed by using differential scanning calorimetry, Fourier transform infrared spectroscopy, and molecular modeling. Scanning electron microscopy shows that bone organic content incinerate gradually through the different temperatures studied. We suggest that the amide regions of the type I collagen molecule (mainly C=O groups of the peptide bonds) will be important in the control of the interactions with the apatite from bone. The amide I infrared bands of the collagen type I change when interacting to apatite, what might confirm our assumption. Bone tissue results in a loss of thermal stability compared to the collagen studied apart, as a consequence of the degradation and further combustion of the collagen in contact with the apatite microcrystals in bone. The thermal behavior of bone is very distinctive. Its main typical combustion temperature is at 360°C with a shoulder at 550°C compared to the thermal behavior of collagen, with the mean combustion peak at ca. 500°C. Our studies with molecular mechanics (MM+ force field) showed different interaction energies of the collagen-like molecule and different models of the apatite crystal planes. We used models of the apatite (100) and (001) planes;additional two planes (001) were explored with phosphate-rich and calcium-rich faces;an energetic preference was found in the latter case. We preliminary conclude that the peptide bond of collagen type I is modified when the molecule interacts with the apatite, producing a decrease in the main peak from ca. 500°C in collagen, up to 350°C in bone. The combustion might be related to collagen type I, as the ΔH energies present only small variations between mineralized and non-mineralized samples. The data obtained here give a molecular perspective into the structural properties of bone and the change in collagen properties caused by the interaction with the apatite. Our study can be useful to understand the biological synthesis of minerals as well as the organic-inorganic interaction and the synthesis of apatite implant materials.展开更多
基金supported by the National Natural Science Foundation of China(32101883)Fellowship China Postdoctoral Science Foundation(2021M693902)National Agricultural Science and Technology Innovation Project(CAAS-ASTIP-2022)。
文摘Bone collagen hydrolysates(peptides)derived from byproduct of animal product processing have been used to produce commercially valuable products due to their potential antioxidant activity.Maillard glycosylated reaction is considered as a promising method to enhance the antioxidant activity of peptides.Hence,this research aims at investigating the Maillard glycosylation activity and antioxidant activity of bone collagen hydrolysates from different sources.In this study,3 glycosylated bone collagen hydrolysates were prepared and characterized,and cytotoxicity and antioxidant activity were analyzed and evaluated.The free amino groups loss,browning intensity,and fluorescence intensity of G-Cbcp(glycosylated chicken bone collagen hydrolysates(peptides))were the heaviest,followed by G-Pbcp(glycosylated porcine bone collagen hydrolysates(peptides))and G-Bbcp(glycosylated bovine bone collagen hydrolysates(peptides)).The results of amino acid analysis showed that amino acid composition of different bone collagen hydrolysates was significantly different and the amino acid decreased to different degrees after Maillard glycosylated reaction,which may lead to differences in Maillard glycosylated reaction activity.Furthermore,the 3 glycosylated hydrolysates showed no significant cytotoxicity.The results showed that glycosylation process significantly increased the antioxidant activity of bone collagen hydrolysates,and G-Cbcp showed the strongest antioxidant activity,followed by G-Pbcp and G-Bbcp.Therefore,compared with the bone collagen hydrolysates,3 glycosylated hydrolysates showed significant characteristic and structural changes,and higher antioxidant activity.
基金granted by the National Key R&D Program of China (2021YFD21001005)National Natural Science Foundation of China (31972102,32101980)+1 种基金Special key project of Chongqing technology innovation and application development (cstc2021jscx-cylhX0014)Chongqing Technology Innovation and Application Development Special Project (cstc2021jscx-tpyzxX0014)。
文摘This study aimed to characterize and identify calcium-chelating peptides from rabbit bone collagen and explore the underlying chelating mechanism.Collagen peptides and calcium were extracted from rabbit bone by instant ejection steam explosion(ICSE)combined with enzymatic hydrolysis,followed by chelation reaction to prepare rabbit bone peptide-calcium chelate(RBCP-Ca).The chelating sites were further analyzed by liquid chromatography-tandem mass(LC-MS/MS)spectrometry while the chelating mechanism and binding modes were investigated.The structural characterization revealed that RBCP successfully chelated with calcium ions.Furthermore,LC-MS/MS analysis indicated that the binding sites included both acidic amino acids(Asp and Glu)and basic amino acids(Lys and Arg),Interestingly,three binding modes,namely Inter-Linking,Loop-Linking and Mono-Linking were for the first time found,while Inter-Linking mode accounted for the highest proportion(75.1%),suggesting that chelation of calcium ions frequently occurred between two peptides.Overall,this study provides a theoretical basis for the elucidation of chelation mechanism of calcium-chelating peptides.
基金supported by the National Institutes of Health under Award Number 1R21AR077881.
文摘Age and diabetes have long been known to induce an oxidative reaction between glucose and collagen,leading to the accumulation of advanced glycation end-products(AGEs)cross-links in collagenous tissues.More recently,AGEs content has been related to loss of bone quality,independent of bone mass,and increased fracture risk with aging and diabetes.Loss of bone quality is mostly attributed to changes in material properties,structural organization,or cellular remodeling.Though all these factors play a role in bone fragility disease,some common recurring patterns can be found between diabetic and age-related bone fragility.The main pattern we will discuss in this viewpoint is the increase of fibrillar collagen stiffness and loss of collagen-induced plasticity with AGE accumulation.This study focused on recent related experimental studies and discusses the correlation between fluorescent AGEs content at the molecular and fibrillar scales,collagen deformation mechanisms at the nanoscale,and resistance to bone fracture at the macroscale.
基金support from the staff of the National Engineering Research Center for Functional Food,Jiangnan Universitysupported by the Postdoctoral Research Funding of Jiangsu Province (2021K269B)National Key Research & Developmental Program of China (2018YFA0900300)。
文摘In this study, yak bone collagen hydrolysate(YBCH)was produced by mixed proteases and provided to standard-diet mice at a different dose(low dose(LD), medium dose(MD), and high dose(HD))to investigate its effects on the composition of gut microbiota and short-chain fatty acids(SCFA)production. It was found that YBCH was mainly composed of small molecular peptides whose molecular weight below 2 000 Da. Notably, supplementation with different doses of YBCH could significantly downregulate the ratio of Firmicutes to Bacteroidetes in the fecal microbiota. At the family level, the Lachnospiraceae abundance was significantly reduced in the YBCH gavage groups(mean reduction ratio 41.7 %, 35.2%, and 36.4% for LD, MD, and HD group, respectively). The predicted functions of gut microbes in the MD group were significantly increased at “lipid metabolism” and “glycan biosynthesis and metabolism”. Moreover, the SCFA production in the YBCH groups was elevated. Especially, the concentration of acetic acid, propionic acid, and butyric acid in the MD group was separately increased 79.7%, 89.2%, and 78.8% than that in the NC group. These results indicated that YBCH might be applied in the development of functional food for intestinal microecological regulation.
文摘This study aimed to utilize micro-computed tomography （micro-CT） analysis to compare new bone formation in rat calvarial defects using chitosan/fibroin-hydroxyapatite （CFB-HAP） or collagen （Bio-Gide） membranes. Fifty-four （54） rats were studied. A circular bony defect （8 mm diameter） was formed in the centre of the calvaria using a trephine bur. The CFB-HAP membrane was prepared by thermally induced phase separation. In the experimental group （n= 18）, the CFB-HAP membrane was used to cover the bony defect, and in the control group （n= 18）, a resorbable collagen membrane （Bio-Gide） was used. In the negative control group （n= 18）, no membrane was used. In each group, six animals were euthanized at 2, 4 and 8 weeks after surgery. The specimens were then analysed using micro-CT. There were significant differences in bone volume （BV） and bone mineral density （BMD） （P〈O.05） between the negative control group and the membrane groups. However, there were no significant differences between the CFB-HAP group and the collagen group. We concluded that the CFB-HAP membrane has significant potential as a guided bone regeneration （GBR） membrane.
基金funded by the emarked fund for China Agriculture Research System (CARS-39)the National Agricultural Science and Technology Innovation Program
文摘Ovine bones are the major by-products after slaughtered. The present study was conducted to extract and characterize acid soluble collagens （ASC） and pepsin soluble collagens （PSC） from ovine bones （Ujumuqin sheep）. Ovine bones collagen were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE） and liquid chromatography-tan- dem mass spectrometry （LC-MS/MS） as type I collagen. The results of Fourier transform infrared （FTIR） spectra analysis testified the existence of triple superhelical structure in both ASC and PSC, showing pepsin did not disrupt the triple helical structure of ovine bones collagen. Glycine, accounting for one-third of total amino acids, was the major amino acid for ovine bones collagen. Higher imino acid content was responsible for higher thermal denaturation temperature of ovine bones collagen compared to fish collagens. The isoelectric point of ASC was lower than PSC due to the higher content of acidic amino acids. Therefore, this study provides the potential reference for collagen extraction and application of ovine bones by-procduct.
基金financially supported by the Postdoctoral Research Foundation of Beijing of China,No.2017-ZZ-120(to FY)the Natural Science Foundation of Beijing of China,No.2164073(to ML)the Beijing Municipal Administration of Hospitals’ Youth Plan of China,No.QML20180804(to ML)
文摘Combinations of biomaterials and cells can effectively target delivery of cells or other therapeutic factors to the brain to rebuild damaged nerve pathways after brain injury.Porous collagen-chitosan scaffolds were prepared by a freeze-drying method based on brain tissue engineering.The scaffolds were impregnated with rat bone marrow mesenchymal stem cells.A traumatic brain injury rat model was established using the 300 g weight free fall impact method.Bone marrow mesenchymal stem cells/collagen-chitosan scaffolds were implanted into the injured brain.Modified neurological severity scores were used to assess the recovery of neurological function.The Morris water maze was employed to determine spatial learning and memory abilities.Hematoxylin-eosin staining was performed to measure pathological changes in brain tissue.Immunohistochemistry was performed for vascular endothelial growth factor and for 5-bromo-2-deoxyuridine(BrdU)/neuron specific enolase and BrdU/glial fibrillary acidic protein.Our results demonstrated that the transplantation of bone marrow mesenchymal stem cells and collagen-chitosan scaffolds to traumatic brain injury rats remarkably reduced modified neurological severity scores,shortened the average latency of the Morris water maze,increased the number of platform crossings,diminished the degeneration of damaged brain tissue,and increased the positive reaction of vascular endothelial growth factor in the transplantation and surrounding areas.At 14 days after transplantation,increased BrdU/glial fibrillary acidic protein expression and decreased BrdU/neuron specific enolase expression were observed in bone marrow mesenchymal stem cells in the injured area.The therapeutic effect of bone marrow mesenchymal stem cells and collagen-chitosan scaffolds was superior to stereotactic injection of bone marrow mesenchymal stem cells alone.To test the biocompatibility and immunogenicity of bone marrow mesenchymal stem cells and collagen-chitosan scaffolds,immunosuppressive cyclosporine was intravenously injected 12 hours before transplantation and 1-5 days after transplantation.The above indicators were similar to those of rats treated with bone marrow mesenchymal stem cells and collagen-chitosan scaffolds only.These findings indicate that transplantation of bone marrow mesenchymal stem cells in a collagen-chitosan scaffold can promote the recovery of neuropathological injury in rats with traumatic brain injury.This approach has the potential to be developed as a treatment for traumatic brain injury in humans.All experimental procedures were approved by the Institutional Animal Investigation Committee of Capital Medical University,China(approval No.AEEI-2015-035)in December 2015.
基金King Saud University,through Vice Deanship of Research Chairs
文摘The aim of the present real time in vivo micro-computed tomography （pCT） and histologic experiment was to assess the efficacy of guided bone regeneration （GBR） around standardized calvarial critical size defects （CSD） using bone marrow-derived mesenchymal stem cells （BMSCs）, and collagen membrane （CM） with and without tricalcium phosphate （TCP） graft material. In the calvaria of nine female Sprague-Dawley rats, full-thickness CSD （diameter 4.6 mm） were created under general anesthesia. Treatment-wise, rats were divided into three groups. In group 1, CSD was covered with a resorbable CM; in group 2, BMSCs were filled in CSD and covered with CM; and in group 3, TCP soaked in BMSCs was placed in CSD and covered with CM. All defects were closed using resorbable sutures. Bone volume and bone mineral density of newly formed bone （NFB） and remaining TCP particles and rate of new bone formation was determined at baseline, 2, 4, 6, and 10 weeks using in vivo pCT. At the lOth week, the rats were killed and calvarial segments were assessed histologically. The results showed that the hardness of NFB was similar to that of the native bone in groups I and 2 as compared to the NFB in group 3. Likewise, values for the modulus of elasticity were also significantly higher in group 3 compared to groups 1 and 2. This suggests that TCP when used in combination with BMSCs and without CM was unable to form bone of significant strength that could possibly provide mechanical ＂lock＂ between the natural bone and NFB. The use of BMSCs as adjuncts to conventional GBR initiated new bone formation as early as 2 weeks of treatment compared to when GBR is attempted without adiunct BMSC therapy.
基金funded by a grant from Shaanxi Provincial Support Project of Scientific Research Development Plan of China,No.2012KCT-16
文摘In this study, we successfully constructed a composite of bone marrow mesenchymal stem cells and a chitosan-collagen scaffold in vitro, transplanted either the composite or bone marrow mesenchymal stem cells alone into the ischemic area in animal models, and compared their effects. At 14 days after co-transplantation of bone marrow mesenchymal stem cells and the hi- tosan-collagen scaffold, neurological function recovered noticeably. Vascular endothelial growth factor expression and nestin-labeled neural precursor cells were detected in the iscbemic area, surrounding tissue, hippocampal dentate gyrus and subventricular zone. Simultaneously, a high level of expression of glial fibrillary acidic protein and a low level of expression of neuron-spe- cific enolase were visible in BrdU-labeled bone marrow mesenchymal stem cells. These findings suggest that transplantation of a composite of bone marrow mesenchymal stem cells and a chi- tosan-collagen scaffold has a neuroprotective effect following ischemic stroke.
基金Supported by Natural National Science Foundation of China,No.31700810 and No.11772073Science and Technology Research Program of Chongqing Municipal Education Commission,No.KJQN201800601+1 种基金Natural Science Foundation of Chongqing,China,No.cstc2020jcyj-msxmX0760Visiting Scholar Foundation of Key Laboratory of Biorheological Science and Technology(Chongqing University),Ministry of Education,No.CQKLBST-2018-007.
文摘BACKGROUND Collagen is one of the most commonly used natural biomaterials for tendon tissue engineering.One of the possible practical ways to further enhance tendon repair is to combine a porous collagen sponge scaffold with a suitable growth factor or cytokine that has an inherent ability to promote the recruitment,proliferation,and tenogenic differentiation of cells.However,there is an incomplete understanding of which growth factors are sufficient and optimal for the tenogenic differentiation of rat bone marrow mesenchymal stem cells(BMSCs)in a collagen sponge-based 3D culture system.AIM To identify one or more ideal growth factors that benefit the proliferation and tenogenic differentiation of rat BMSCs in a porous collagen sponge scaffold.METHODS We constructed a 3D culture system based on a type I collagen sponge scaffold.The surface topography of the collagen sponge scaffold was observed by scanning electron microscopy.Primary BMSCs were isolated from Sprague-Dawley rats.Cell survival on the surfaces of the scaffolds with different growth factors was assessed by live/dead assay and CCK-8 assay.The mRNA and protein expression levels were confirmed by quantitative real-time polymerase chain reaction and Western blot,respectively.The deposited collagen was assessed by Sirius Red staining.RESULTS Transforming growth factorβ1(TGF-β1)showed great promise in the tenogenic differentiation of BMSCs compared to growth differentiation factor 7(GDF-7)and insulin-like growth factor 1(IGF-1)in both the 2D and 3D cultures,and the 3D culture enhanced the differentiation of BMSCs into tenocytes well beyond the level of induction in the 2D culture after TGF-β1 treatment.In the 2D culture,the proliferation of the BMSCs showed no significant changes compared to the control group after TGF-β1,IGF-1,or GDF-7 treatment.However,TGF-β1 and GDF-7 could increase the cell proliferation in the 3D culture.Strangely,we also found more dead cells in the BMSC-collagen sponge constructs that were treated with TGF-β1.Moreover,TGF-β1 promoted more collagen deposition in both the 2D and 3D cultures.CONCLUSION Collagen sponge-based 3D culture with TGF-β1 enhances the responsiveness of the proliferation and tenogenic differentiation of rat BMSCs.
基金Supported by Beijing Municipal Hospital Management Center“Cultivation Plan”,No.PX2022032.
文摘BACKGROUND Intracranial and extracranial artery stenosis is associated with cerebral infarction.Vascular calcification and atherosclerosis are the main causes of stenosis and major risk factors for cardiovascular and cerebrovascular events in patients with type 2 diabetes mellitus(T2DM).Bone turnover biomarkers(BTMs)are associated with vascular calcification,atherosclerosis,glucose,and lipid metabolism.AIM To investigate the association of circulating BTM levels with severe intracranial and extracranial artery stenosis in patients with T2DM.METHODS For this cross-sectional study including 257 T2DM patients,levels of the BTMs serum osteocalcin(OC),C-terminal cross-linked telopeptide of type I collagen(CTX),and procollagen type I N-peptide were measured by electrical chemiluminescent immunoassay,and artery stenosis was assessed by color Doppler and transcranial Doppler.Patients were grouped according to the existence and location(intracranial vs.extracranial)of artery stenosis.Correlations between BTM levels,previous stroke,stenosis location,and glucose and lipid metabolism were analyzed.RESULTS T2DM patients with severe artery stenosis had a higher frequency of previous stroke and levels of all three tested BTMs(all P<0.05)than patients without.Some differences in OC and CTX levels were observed according to the location of artery stenosis.Significant associations were also observed between BTM levels and some glucose and lipid homeostasis parameters.On multivariate logistic regression analysis,all BTMs were significant predictors of artery stenosis in T2DM patients with and without adjustment for confounding factors(all P<0.001),and receiver operating characteristic curve analysis demonstrated the ability of BTM levels to predict artery stenosis in T2DM patients.CONCLUSION BTM levels were found to be independent risk factors for severe intracranial and extracranial artery stenosis and were differentially associated with glucose and lipid metabolism in patients with T2DM.Therefore,BTMs may be promising biomarkers and potential therapeutic targets for artery stenosis.
文摘A synthetizing material blended with two distinct proteins (collagen and casein) and mineral mixture, was developed in order to evaluate their properties suitable for possible applications in the biomedical such as inducing the regeneration of damaged bone, either due to an accident or illness. Samples were evaluated by 1) Mechanical properties tests under the bending, 2) Scanning electronic microscopy and 3) Infrared spectroscopy were carried out. The results showed that the developed material has breaking strength and structure characteristics associated with the protein used in their composition. This fact suggests that the used protein determines the resistance of the material, in such a way according to the required use, being able to choose appropriate strength and duration either short or long time. The material composition for specific use, in order to find the most suitable mixture for bone replacement, or induce bone recovery, according to the required properties similar to those of damaged living tissue.
基金the National Autonomous University of Mexico for financial support(grant DGAPA-IN100303)A.H.thanks the National Council of Science and Technology of Mexico(CONACyT)and DAAD for scholarships
文摘An insight into the interaction of collagen type I with apatite in bone tissue was performed by using differential scanning calorimetry, Fourier transform infrared spectroscopy, and molecular modeling. Scanning electron microscopy shows that bone organic content incinerate gradually through the different temperatures studied. We suggest that the amide regions of the type I collagen molecule (mainly C=O groups of the peptide bonds) will be important in the control of the interactions with the apatite from bone. The amide I infrared bands of the collagen type I change when interacting to apatite, what might confirm our assumption. Bone tissue results in a loss of thermal stability compared to the collagen studied apart, as a consequence of the degradation and further combustion of the collagen in contact with the apatite microcrystals in bone. The thermal behavior of bone is very distinctive. Its main typical combustion temperature is at 360°C with a shoulder at 550°C compared to the thermal behavior of collagen, with the mean combustion peak at ca. 500°C. Our studies with molecular mechanics (MM+ force field) showed different interaction energies of the collagen-like molecule and different models of the apatite crystal planes. We used models of the apatite (100) and (001) planes;additional two planes (001) were explored with phosphate-rich and calcium-rich faces;an energetic preference was found in the latter case. We preliminary conclude that the peptide bond of collagen type I is modified when the molecule interacts with the apatite, producing a decrease in the main peak from ca. 500°C in collagen, up to 350°C in bone. The combustion might be related to collagen type I, as the ΔH energies present only small variations between mineralized and non-mineralized samples. The data obtained here give a molecular perspective into the structural properties of bone and the change in collagen properties caused by the interaction with the apatite. Our study can be useful to understand the biological synthesis of minerals as well as the organic-inorganic interaction and the synthesis of apatite implant materials.
