This study compares the summer atmospheric water cycle,including moisture sources and consumption,in the upstream,midstream,and downstream regions of the Yarlung Zangbo River Basin in the southern Tibetan Plateau.The ...This study compares the summer atmospheric water cycle,including moisture sources and consumption,in the upstream,midstream,and downstream regions of the Yarlung Zangbo River Basin in the southern Tibetan Plateau.The evolutions of moisture properties under the influence of the westerly and summer southerly monsoon are examined using 5-yr multi-source measurements and ERA5 reanalysis data.Note that moisture consumption in this study is associated with clouds,precipitation,and diabatic heating.Compared to the midstream and downstream regions,the upstream region has less moisture,clouds,and precipitation,where the moisture is brought by the westerly.In early August,the vertical wet advection over this region becomes enhanced and generates more high clouds and precipitation.The midstream region has moisture carried by the westerly in June and by the southerly monsoon from July to August.The higher vertical wet advection maximum here forms more high clouds,with a precipitation peak in early July.The downstream region is mainly affected by the southerly-driven wet advection.The rich moisture and strong vertical wet advection here produce the most clouds and precipitation among the three regions,with a precipitation peak in late June.The height of the maximum moisture condensation is different between the midstream region(325 hPa)and the other two regions(375 hPa),due to the higher upward motion maximum in the midstream region.The diabatic heating structures show that stratiform clouds dominate the upstream region,stratiform clouds and deep convection co-exist in the midstream region,and deep convection systems characterize the downstream region.展开更多
Three-dimensional(3D)bioprinting based on traditional 3D printing is an emerging technology that is used to precisely assemble biocompatible materials and cells or bioactive factors into advanced tissue engineering so...Three-dimensional(3D)bioprinting based on traditional 3D printing is an emerging technology that is used to precisely assemble biocompatible materials and cells or bioactive factors into advanced tissue engineering solutions.Similar technology,particularly photo-cured bioprinting strategies,plays an important role in the field of tissue engineering research.The successful implementation of 3D bioprinting is based on the properties of photopolymerized materials.Photocrosslinkable hydrogel is an attractive biomaterial that is polymerized rapidly and enables process control in space and time.Photopolymerization is frequently initiated by ultraviolet(UV)or visible light.However,UV light may cause cell damage and thereby,affect cell viability.Thus,visible light is considered to be more biocompatible than UV light for bioprinting.In this review,we provide an overview of photo curing-based bioprinting technologies,and describe a visible light crosslinkable bioink,including its crosslinking mechanisms,types of visible light initiator,and biomedical applications.We also discuss existing challenges and prospects of visible light-induced 3D bioprinting devices and hydrogels in biomedical areas.展开更多
Articular cartilage(AC)is an avascular and flexible connective tissue located on the bone surface in the diarthrodial joints.AC defects are common in the knees of young and physically active individuals.Because of the...Articular cartilage(AC)is an avascular and flexible connective tissue located on the bone surface in the diarthrodial joints.AC defects are common in the knees of young and physically active individuals.Because of the lack of suitable tissue-engineered artificial matrices,current therapies for AC defects,espe-cially full-thickness AC defects and osteochondral interfaces,fail to replace or regenerate damaged carti-lage adequately.With rapid research and development advancements in AC tissue engineering(ACTE),functionalized hydrogels have emerged as promising cartilage matrix substitutes because of their favor-able biomechanical properties,water content,swelling ability,cytocompatibility,biodegradability,and lubricating behaviors.They can be rationally designed and conveniently tuned to simulate the extracel-lular matrix of cartilage.This article briefly introduces the composition,structure,and function of AC and its defects,followed by a comprehensive review of the exquisite(bio)design and(bio)fabrication of func-tionalized hydrogels for AC repair.Finally,we summarize the challenges encountered in functionalized hydrogel-based strategies for ACTE both in vivo and in vitro and the future directions for clinical translation.展开更多
High energy bone fractures resulting from impact trauma are often accompanied by subcutaneous soft tissue injuries, even if the skin remains intact. There is evidence that such closed soft tissue injuries affect the h...High energy bone fractures resulting from impact trauma are often accompanied by subcutaneous soft tissue injuries, even if the skin remains intact. There is evidence that such closed soft tissue injuries affect the healing of bone fractures, and vice versa. Despite this knowledge, most impact trauma studies in animals have focussed on bone fractures or soft tissue trauma in isolation. However, given the simultaneous impact on both tissues a better understanding of the interaction between these two injuries is necessary to optimise clinical treatment. The aim of this study was therefore to develop a new experimental model and characterise, for the first time, the healing of a complex fracture with concurrent closed soft tissue trauma in sheep. A pendulum impact device was designed to deliver a defined and standardised impact to the distal thigh of sheep, causing a reproducible contusion injury to the subcutaneous soft tissues. In a subsequent procedure, a reproducible femoral butterfly fracture (AO C3-type) was created at the sheep’s femur, which was initially stabilised for 5 days by an external fixator construct to allow for soft tissue swelling to recede, and ultimately in a bridging construct using locking plates. The combined injuries were applied to twelve sheep and the healing observed for four or eight weeks (six animals per group) until sacrifice. The pendulum impact led to a moderate to severe circumferential soft tissue injury with significant bruising, haematomas and partial muscle disruptions. Posttraumatic measurements showed elevated intra-compartmental pressure and circulatory tissue breakdown markers, with recovery to normal, pre-injury values within four days. Clinically, no neurovascular deficiencies were observed. Bi-weekly radiological analysis of the healing fractures showed progressive callus healing over time, with the average number of callus bridges increasing from 0.4 at two weeks to 4.2 at eight weeks. Biomechanical testing after sacrifice showed in- creasing torsional stiffness between four and eight weeks healing time from 10% to 100%, and increasing ultimate torsional strength from 10% to 64% (relative to the contralateral control limb). Our results demonstrate the robust healing of a complex femur fracture in the presence of a severe soft tissue contusion injury in sheep and demonstrate the establishment of a clinically relevant experimental model, for research aimed at improving the treatment of bone fractures accompanied by closed soft tissue injuries.展开更多
Cartilage Decellularized ExtraCellular Matrix(dECM)materials have shown promising cartilage regenera-tion capacity due to their chondrogenic bioactivity.However,the limited retention of ECM components and the reduced ...Cartilage Decellularized ExtraCellular Matrix(dECM)materials have shown promising cartilage regenera-tion capacity due to their chondrogenic bioactivity.However,the limited retention of ECM components and the reduced integrity of functional ECM molecules during traditional decellularization processes im-pair the biomimicry of these materials.The current study aims to fabricate biomimetic materials con-taining decellularized cartilage particles that have an intact molecular structure and native composition as biomaterial inks and hydrogels for cartilage repair.For this,we established a novel two-fraction de-cellularization strategy for the preparation of reconstituted dECM(rdECM)particles by mixing the two-fraction components,as well as a one-fraction decellularization strategy for the preparation of biomimetic dECM(bdECM)particles.Hyaluronic acid-tyramine(THA)hydrogels containing rdECM or bdECM particles were produced and characterized via rheological test,swelling and stability evaluation,and compression test.The results showed that our novel decellularization strategies preserved intact proteoglycans and collagen at a higher retention rate with adequate DNA removal compared to traditional methods of de-cellularization.The addition of rdECM or bdECM particles significantly increased the shear moduli of the THA bioinks while preserving their shear-thinning properties.bdECM particle-embedded THA hydrogels also achieved long-term stability with a swelling ratio of 70%and high retention of glycosaminoglycans and collagen after long-term incubation,while rdECM particle-embedded THA hydrogels showed unsat-isfactory stability as self-standing biomaterials.Compared to pure THA hydrogels,the addition of bdECM particles significantly enhanced the compression moduli.In summary,our decellularization methods are successful in the retention of functional and intact cartilage components with high yield.Both rdECM and bdECM particles can be supplemented in THA bioinks for biomimetic cartilage 3D printing.Hydro-gels with cartilage bdECM particles possess the functional structure and the natural composition of car-tilage ECM,long-term stability,and enhanced mechanical properties,and are promising biomaterials for cartilage repair.展开更多
Osteochondral defects (OCD) are common but difficult to heal due to the low intrinsic repair capacity of cartilage and its complex hierarchical structure. In osteoarthritis (OA), OCD become more challenging to repair ...Osteochondral defects (OCD) are common but difficult to heal due to the low intrinsic repair capacity of cartilage and its complex hierarchical structure. In osteoarthritis (OA), OCD become more challenging to repair as both cartilage and subchondral bone regeneration are further impaired due to the arthritic environment. Numerous biomaterials have been developed and tested in osteochondral defects while ignoring the inflammatory environment. To target this challenging underlying pathophysiology, we designed and fabricated a biphasic porous and degradable scaffold incorporating anti-inflammatory and anabolic molecules by low-temperature rapid prototyping technology, and its effects on promoting osteochondral regeneration were evaluated using our well-established OA-OCD rabbit model. The biphasic porous scaffolds consisted of poly lactic-co-glycolic acid (PLGA) with kartogenin (KGN) for cartilage repair and PLGA and β-calcium phosphate (PLGA/β-TCP) with cinnamaldehyde (CIN) for subchondral bone repair. KGN is a molecule for promoting chondrogenesis and CIN is a phytomolecule for enhancing osteogenesis and alleviating inflammation. The biphasic scaffolds PLGA/KGN-PLGA/β-TCP/CIN (PK/PTC) with bio-mimic structure provided stable mechanical properties and exhibited excellent biocompatibility to support cell adhesion, proliferation, migration, and distribution. Furthermore, KGN and CIN within biphasic scaffolds could be released in a controlled and sustained mode, and the biphasic scaffold degraded slowly in vitro . Evaluating the repair of 16-weeks post-implantation into critically sized OA-OCD rabbit models revealed that the biphasic scaffold could promote subchondral bone and cartilage regeneration, as well as reverse subchondral osteosclerosis caused by inflammation in vivo . These findings support the utilization of the PK/PTC scaffold for osteochondral regeneration and provide a promising potential strategy for clinical application for the treatment of patients with OA-OCD.展开更多
Neutrophils play a pivotal role in orchestrating the immune system response to biomaterials,the onset and resolution of chronic inflammation,and macrophage polarization.However,the neutrophil response to biomaterials ...Neutrophils play a pivotal role in orchestrating the immune system response to biomaterials,the onset and resolution of chronic inflammation,and macrophage polarization.However,the neutrophil response to biomaterials and the consequent impact on tissue engineering approaches is still scarcely understood.Here,we report an in vitro culture model that comprehensively describes the most important neutrophil functions in the light of tissue repair.We isolated human primary neutrophils from peripheral blood and exposed them to a panel of hard,soft,naturally-and synthetically-derived materials.The overall trend showed increased neutrophil survival on naturally derived constructs,together with higher oxidative burst,decreased myeloperoxidase and neutrophil elastase and decreased cytokine secretion compared to neutrophils on synthetic materials.The culture model is a step to better understand the immune modulation elicited by biomaterials.Further studies are needed to correlate the neutrophil response to tissue healing and to elucidate the mechanism triggering the cell response and their consequences in determining inflammation onset and resolution.展开更多
It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of ...It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of life science after cellular and molecular bioscience.Nevertheless,despite decades of rapid de-velopment,tissue-engineered biomaterials have not been widely used clinically.Biomaterials constructed by physical and chemical methods have lots of difficulty in precisely mimicking the macroscopic and mi-croscopic structures of human tissues.The ultimate way to build organoid tissue for regeneration is to enable the cells to take the initiative and build suitable functions.Based on the thoughts of tissue engi-neering,organoid technology holds great potential as a research tool for a wide range of fields,including developmental biology,disease pathology,cell biology,precision medicine,and drug toxicity and efficacy testing.This technology also holds tremendous potential for regenerative medicine,as organoids present the possibility for autologous and allogeneic cell therapy through the replacement of damaged or dis-eased tissues with organoid-propagated tissue or stem cell populations.In this review work,we briefly outlook the development history of organoid technology,summarize the current bottlenecks and the un-derlying reasons,and propose the unified term“function-oriented design in tissue engineering”,a new topic that may provide a solution to overcome these bottlenecks.展开更多
The depletion of chondroitin sulfates(CSs)within the intervertebral disc(IVD)during degenerative disc disease(DDD)results in a decrease in tissue hydration,a loss of fluid movement,cell apoptosis,a loss of nerve growt...The depletion of chondroitin sulfates(CSs)within the intervertebral disc(IVD)during degenerative disc disease(DDD)results in a decrease in tissue hydration,a loss of fluid movement,cell apoptosis,a loss of nerve growth inhibition and ultimately,the loss of disc function.To date,little is known with regards to the structure and content of chondroitin sulfates(CSs)during IVD ageing.The behavior of glycosaminoglycans(GAGs),specifically CSs,as well as xylosyltransferase I(XT-I)and glucuronyltransferase I(GT-I),two key enzymes involved in CS synthesis as a primer of glycosaminoglycan(GAG)chain elongation and GAG synthesis in the nucleus pulposus(NP),respectively,were evaluated in a bovine ageing IVD model.Here,we showed significant changes in the composition of GAGs during the disc ageing process(6-month-old,2-year-old and 8-year-old IVDs representing the immature to mature skeleton).The CS quantity and composition of annulus fibrosus(AF)and NP were determined.The expression of both XT-I and GT-I was detected using immunohistochemistry.A significant decrease in GAGs was observed during the ageing process.CSs are affected at both the structural and quantitative levels with important changes in sulfation observed upon maturity,which correlated with a decrease in the expression of both XT-I and GT-I.A progressive switch of the sulfation profile was noted in both NP and AF tissues from 6 months to 8 years.These changes give an appreciation of the potential impact of CSs on the disc biology and the development of therapeutic approaches for disc regeneration and repair.展开更多
It has been proven that the mechanical microenvironment can impact the differentiation of mesenchymal stem cells(MSCs).However,the effect of mechanical stimuli in biofabricating hydroxyapatite scaffolds on the inflamm...It has been proven that the mechanical microenvironment can impact the differentiation of mesenchymal stem cells(MSCs).However,the effect of mechanical stimuli in biofabricating hydroxyapatite scaffolds on the inflammatory response of MSCs remains unclear.This study aimed to investigate the effect of mechanical loading on the inflammatory response of MSCs seeded on scaffolds.Cyclic mechanical loading was applied to biofabricate the cell-scaffold composite for 15 min/day over 7,14,or 21 days.At the predetermined time points,culture supernatant was collected for inflammatory mediator detection,and gene expression was analyzed by qRT-PCR.The results showed that the expression of inflammatory mediators(IL1B and IL8)was downregulated(p<0.05)and the expression of ALP(p<0.01)and COL1A1(p<0.05)was upregulated under mechanical loading.The cell-scaffold composites biofabricated with or without mechanical loading were freeze-dried to prepare extracellular matrix-based scaffolds(ECM-based scaffolds).Murine macrophages were seeded on the ECM-based scaffolds to evaluate their polarization.The ECM-based scaffolds that were biofabricated with mechanical loading before freeze-drying enhanced the expression of M2 polarization-related biomarkers(Arginase 1 and Mrc1,p<0.05)of macrophages in vitro and increased bone volume/total volume ratio in vivo.Overall,these findings demonstrated that mechanical loading could dually modulate the inflammatory responses and osteogenic differentiation of MSCs.Besides,the ECM-based scaffolds that were biofabricated with mechanical loading before freeze-drying facilitated the M2 polarization of macrophages in vitro and bone regeneration in vivo.Mechanical loading may be a promising biofabrication strategy for bone biomaterials.展开更多
The osteogenic microenvironment of bone-repairing materials plays a key role in accelerating bone regeneration but remains incompletely defined,which significantly limits the application of such bioactive materials.He...The osteogenic microenvironment of bone-repairing materials plays a key role in accelerating bone regeneration but remains incompletely defined,which significantly limits the application of such bioactive materials.Here,the transcriptional landscapes of different osteogenic microenvironments,including three-dimensional(3D)hydroxyapatite(HA)scaffolds and osteogenic medium(OM),for mesenchymal stromal cells(MSCs)in vitro were mapped at single-cell resolution.Our findings suggested that an osteogenic process reminiscent of endochondral ossification occurred in HA scaffolds through sequential activation of osteogenic-related signaling pathways,along with inflammation and angiogenesis,but inhibition of adipogenesis and fibrosis.Moreover,we revealed the mechanism during OM-mediated osteogenesis involves the ZBTB16 and WNT signaling pathways.Heterogeneity of MSCs was also demonstrated.In vitro ossification of LRRC75A+MSCs was shown to have better utilization of WNT-related ossification process,and PCDH10+MSCs with superiority in hydroxyapatite-related osteogenic process.These findings provided further understanding of the cellular activity modulated by OM conditions and HA scaffolds,providing new insights for the improvement of osteogenic biomaterials.This atlas provides a blueprint for research on MSC heterogeneity and the osteogenic microenvironment of HA scaffolds and a database reference for the application of bioactive materials for bone regeneration.展开更多
基金supported by The Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0105)the National Natural Science Foundation of China(91437221,91837204).
文摘This study compares the summer atmospheric water cycle,including moisture sources and consumption,in the upstream,midstream,and downstream regions of the Yarlung Zangbo River Basin in the southern Tibetan Plateau.The evolutions of moisture properties under the influence of the westerly and summer southerly monsoon are examined using 5-yr multi-source measurements and ERA5 reanalysis data.Note that moisture consumption in this study is associated with clouds,precipitation,and diabatic heating.Compared to the midstream and downstream regions,the upstream region has less moisture,clouds,and precipitation,where the moisture is brought by the westerly.In early August,the vertical wet advection over this region becomes enhanced and generates more high clouds and precipitation.The midstream region has moisture carried by the westerly in June and by the southerly monsoon from July to August.The higher vertical wet advection maximum here forms more high clouds,with a precipitation peak in early July.The downstream region is mainly affected by the southerly-driven wet advection.The rich moisture and strong vertical wet advection here produce the most clouds and precipitation among the three regions,with a precipitation peak in late June.The height of the maximum moisture condensation is different between the midstream region(325 hPa)and the other two regions(375 hPa),due to the higher upward motion maximum in the midstream region.The diabatic heating structures show that stratiform clouds dominate the upstream region,stratiform clouds and deep convection co-exist in the midstream region,and deep convection systems characterize the downstream region.
基金supported by the Key-Area Research and Development Program of Guangdong Province(2019B010941001)the Shenzhen Double Chain Project for Innovation and Development Industry supported by the Bureau of Industry and Information Technology of Shenzhen(201908141541)Shenzhen Fundamental Research Foundation(GJHZ20170314154845576 and GJHS20170314161106706).
文摘Three-dimensional(3D)bioprinting based on traditional 3D printing is an emerging technology that is used to precisely assemble biocompatible materials and cells or bioactive factors into advanced tissue engineering solutions.Similar technology,particularly photo-cured bioprinting strategies,plays an important role in the field of tissue engineering research.The successful implementation of 3D bioprinting is based on the properties of photopolymerized materials.Photocrosslinkable hydrogel is an attractive biomaterial that is polymerized rapidly and enables process control in space and time.Photopolymerization is frequently initiated by ultraviolet(UV)or visible light.However,UV light may cause cell damage and thereby,affect cell viability.Thus,visible light is considered to be more biocompatible than UV light for bioprinting.In this review,we provide an overview of photo curing-based bioprinting technologies,and describe a visible light crosslinkable bioink,including its crosslinking mechanisms,types of visible light initiator,and biomedical applications.We also discuss existing challenges and prospects of visible light-induced 3D bioprinting devices and hydrogels in biomedical areas.
基金supported by grants from the AO Foundation (AOOCD Consortium TA1711481)Areas of Excellence Scheme from the University Grant Council of Hong Kong (Ao E/M-402/20)+1 种基金Theme-based Research Scheme from the University Grant Council of Hong Kong (T13-402/17-N)Key-Area Research and Development Program of Guangdong Province (2019B010941001)
文摘Articular cartilage(AC)is an avascular and flexible connective tissue located on the bone surface in the diarthrodial joints.AC defects are common in the knees of young and physically active individuals.Because of the lack of suitable tissue-engineered artificial matrices,current therapies for AC defects,espe-cially full-thickness AC defects and osteochondral interfaces,fail to replace or regenerate damaged carti-lage adequately.With rapid research and development advancements in AC tissue engineering(ACTE),functionalized hydrogels have emerged as promising cartilage matrix substitutes because of their favor-able biomechanical properties,water content,swelling ability,cytocompatibility,biodegradability,and lubricating behaviors.They can be rationally designed and conveniently tuned to simulate the extracel-lular matrix of cartilage.This article briefly introduces the composition,structure,and function of AC and its defects,followed by a comprehensive review of the exquisite(bio)design and(bio)fabrication of func-tionalized hydrogels for AC repair.Finally,we summarize the challenges encountered in functionalized hydrogel-based strategies for ACTE both in vivo and in vitro and the future directions for clinical translation.
文摘High energy bone fractures resulting from impact trauma are often accompanied by subcutaneous soft tissue injuries, even if the skin remains intact. There is evidence that such closed soft tissue injuries affect the healing of bone fractures, and vice versa. Despite this knowledge, most impact trauma studies in animals have focussed on bone fractures or soft tissue trauma in isolation. However, given the simultaneous impact on both tissues a better understanding of the interaction between these two injuries is necessary to optimise clinical treatment. The aim of this study was therefore to develop a new experimental model and characterise, for the first time, the healing of a complex fracture with concurrent closed soft tissue trauma in sheep. A pendulum impact device was designed to deliver a defined and standardised impact to the distal thigh of sheep, causing a reproducible contusion injury to the subcutaneous soft tissues. In a subsequent procedure, a reproducible femoral butterfly fracture (AO C3-type) was created at the sheep’s femur, which was initially stabilised for 5 days by an external fixator construct to allow for soft tissue swelling to recede, and ultimately in a bridging construct using locking plates. The combined injuries were applied to twelve sheep and the healing observed for four or eight weeks (six animals per group) until sacrifice. The pendulum impact led to a moderate to severe circumferential soft tissue injury with significant bruising, haematomas and partial muscle disruptions. Posttraumatic measurements showed elevated intra-compartmental pressure and circulatory tissue breakdown markers, with recovery to normal, pre-injury values within four days. Clinically, no neurovascular deficiencies were observed. Bi-weekly radiological analysis of the healing fractures showed progressive callus healing over time, with the average number of callus bridges increasing from 0.4 at two weeks to 4.2 at eight weeks. Biomechanical testing after sacrifice showed in- creasing torsional stiffness between four and eight weeks healing time from 10% to 100%, and increasing ultimate torsional strength from 10% to 64% (relative to the contralateral control limb). Our results demonstrate the robust healing of a complex femur fracture in the presence of a severe soft tissue contusion injury in sheep and demonstrate the establishment of a clinically relevant experimental model, for research aimed at improving the treatment of bone fractures accompanied by closed soft tissue injuries.
基金AO Foundation and AOSpine Inter-national.Peng Guo and Nan Jiang were funded by Sino Swiss Sci-ence and Technology Cooperation Program(Nos.EG-CN_01-032019 and EG-CN_04-042018)China Scholarship Council.MD and GM gratefully acknowledge funding from the Swiss National Sci-ence Foundation(SNSF,No.310030E_189310).
文摘Cartilage Decellularized ExtraCellular Matrix(dECM)materials have shown promising cartilage regenera-tion capacity due to their chondrogenic bioactivity.However,the limited retention of ECM components and the reduced integrity of functional ECM molecules during traditional decellularization processes im-pair the biomimicry of these materials.The current study aims to fabricate biomimetic materials con-taining decellularized cartilage particles that have an intact molecular structure and native composition as biomaterial inks and hydrogels for cartilage repair.For this,we established a novel two-fraction de-cellularization strategy for the preparation of reconstituted dECM(rdECM)particles by mixing the two-fraction components,as well as a one-fraction decellularization strategy for the preparation of biomimetic dECM(bdECM)particles.Hyaluronic acid-tyramine(THA)hydrogels containing rdECM or bdECM particles were produced and characterized via rheological test,swelling and stability evaluation,and compression test.The results showed that our novel decellularization strategies preserved intact proteoglycans and collagen at a higher retention rate with adequate DNA removal compared to traditional methods of de-cellularization.The addition of rdECM or bdECM particles significantly increased the shear moduli of the THA bioinks while preserving their shear-thinning properties.bdECM particle-embedded THA hydrogels also achieved long-term stability with a swelling ratio of 70%and high retention of glycosaminoglycans and collagen after long-term incubation,while rdECM particle-embedded THA hydrogels showed unsat-isfactory stability as self-standing biomaterials.Compared to pure THA hydrogels,the addition of bdECM particles significantly enhanced the compression moduli.In summary,our decellularization methods are successful in the retention of functional and intact cartilage components with high yield.Both rdECM and bdECM particles can be supplemented in THA bioinks for biomimetic cartilage 3D printing.Hydro-gels with cartilage bdECM particles possess the functional structure and the natural composition of car-tilage ECM,long-term stability,and enhanced mechanical properties,and are promising biomaterials for cartilage repair.
基金supported by the collaborative project from the National Key R&D Program of China and Innovation and Tech-nology Fund Mainland-Hong Kong Joint Funding Scheme(Nos.2021YFE0202300 and MHP/011/20)the Sino-Swiss collaborative project from the Ministry of Science and Technology and the Swiss National Science Foundation under the SSSTC program(Grant Nos.2015DFG32200 and 156362)+2 种基金Shenzhen Collaborative Innovation Plan-International Cooperation Project(Grant No.GJHZ20190821160803823)Development and Reform Commission of Shenzhen Municipality(2019)(No.561)Shenzhen Double Chain Project for Innovation and Development Industry supported by Bureau of Industry and Information Technology of Shenzhen(No.201908141541).
文摘Osteochondral defects (OCD) are common but difficult to heal due to the low intrinsic repair capacity of cartilage and its complex hierarchical structure. In osteoarthritis (OA), OCD become more challenging to repair as both cartilage and subchondral bone regeneration are further impaired due to the arthritic environment. Numerous biomaterials have been developed and tested in osteochondral defects while ignoring the inflammatory environment. To target this challenging underlying pathophysiology, we designed and fabricated a biphasic porous and degradable scaffold incorporating anti-inflammatory and anabolic molecules by low-temperature rapid prototyping technology, and its effects on promoting osteochondral regeneration were evaluated using our well-established OA-OCD rabbit model. The biphasic porous scaffolds consisted of poly lactic-co-glycolic acid (PLGA) with kartogenin (KGN) for cartilage repair and PLGA and β-calcium phosphate (PLGA/β-TCP) with cinnamaldehyde (CIN) for subchondral bone repair. KGN is a molecule for promoting chondrogenesis and CIN is a phytomolecule for enhancing osteogenesis and alleviating inflammation. The biphasic scaffolds PLGA/KGN-PLGA/β-TCP/CIN (PK/PTC) with bio-mimic structure provided stable mechanical properties and exhibited excellent biocompatibility to support cell adhesion, proliferation, migration, and distribution. Furthermore, KGN and CIN within biphasic scaffolds could be released in a controlled and sustained mode, and the biphasic scaffold degraded slowly in vitro . Evaluating the repair of 16-weeks post-implantation into critically sized OA-OCD rabbit models revealed that the biphasic scaffold could promote subchondral bone and cartilage regeneration, as well as reverse subchondral osteosclerosis caused by inflammation in vivo . These findings support the utilization of the PK/PTC scaffold for osteochondral regeneration and provide a promising potential strategy for clinical application for the treatment of patients with OA-OCD.
文摘Neutrophils play a pivotal role in orchestrating the immune system response to biomaterials,the onset and resolution of chronic inflammation,and macrophage polarization.However,the neutrophil response to biomaterials and the consequent impact on tissue engineering approaches is still scarcely understood.Here,we report an in vitro culture model that comprehensively describes the most important neutrophil functions in the light of tissue repair.We isolated human primary neutrophils from peripheral blood and exposed them to a panel of hard,soft,naturally-and synthetically-derived materials.The overall trend showed increased neutrophil survival on naturally derived constructs,together with higher oxidative burst,decreased myeloperoxidase and neutrophil elastase and decreased cytokine secretion compared to neutrophils on synthetic materials.The culture model is a step to better understand the immune modulation elicited by biomaterials.Further studies are needed to correlate the neutrophil response to tissue healing and to elucidate the mechanism triggering the cell response and their consequences in determining inflammation onset and resolution.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.U22A20162,31900583,32071351,81772400,82102604,and 81960395)the Natural Science Foundation of Guangzhou City(No.201807010031)+5 种基金the Foundation of Shenzhen Committee for Science and Technology Innovation(Nos.JCYJ20190809142211354,and GJHZ20180929160004704)the Sanming Project of Medicine in Shenzhen(No.SZSM201911002)the Beijing Municipal Health Commission(Nos.BMHC-2021-6,BMHC-2019-9,BMHC-2018-4,and PXM2020_026275_000002)the AOCMF Translational approaches for bone constructs(No.AOCMF-21-04S)the Sun Yatsen University Clinical Research 5010 Program(No.2019009)the Academic Affairs Office of Sun Yat-sen University(Nos.202211583,and 202211589).
文摘It has always been a dream to construct tissues and even organs for transplantation to replace those with defects caused by diseases or injuries.Tissue engineering is another milestone in the developmental history of life science after cellular and molecular bioscience.Nevertheless,despite decades of rapid de-velopment,tissue-engineered biomaterials have not been widely used clinically.Biomaterials constructed by physical and chemical methods have lots of difficulty in precisely mimicking the macroscopic and mi-croscopic structures of human tissues.The ultimate way to build organoid tissue for regeneration is to enable the cells to take the initiative and build suitable functions.Based on the thoughts of tissue engi-neering,organoid technology holds great potential as a research tool for a wide range of fields,including developmental biology,disease pathology,cell biology,precision medicine,and drug toxicity and efficacy testing.This technology also holds tremendous potential for regenerative medicine,as organoids present the possibility for autologous and allogeneic cell therapy through the replacement of damaged or dis-eased tissues with organoid-propagated tissue or stem cell populations.In this review work,we briefly outlook the development history of organoid technology,summarize the current bottlenecks and the un-derlying reasons,and propose the unified term“function-oriented design in tissue engineering”,a new topic that may provide a solution to overcome these bottlenecks.
基金This publication has emanated from research conducted with the financial support of Science Foundation Ireland(SFI)cofunded under the European Regional Development Fund under Grant Number 13/RC/2073.
文摘The depletion of chondroitin sulfates(CSs)within the intervertebral disc(IVD)during degenerative disc disease(DDD)results in a decrease in tissue hydration,a loss of fluid movement,cell apoptosis,a loss of nerve growth inhibition and ultimately,the loss of disc function.To date,little is known with regards to the structure and content of chondroitin sulfates(CSs)during IVD ageing.The behavior of glycosaminoglycans(GAGs),specifically CSs,as well as xylosyltransferase I(XT-I)and glucuronyltransferase I(GT-I),two key enzymes involved in CS synthesis as a primer of glycosaminoglycan(GAG)chain elongation and GAG synthesis in the nucleus pulposus(NP),respectively,were evaluated in a bovine ageing IVD model.Here,we showed significant changes in the composition of GAGs during the disc ageing process(6-month-old,2-year-old and 8-year-old IVDs representing the immature to mature skeleton).The CS quantity and composition of annulus fibrosus(AF)and NP were determined.The expression of both XT-I and GT-I was detected using immunohistochemistry.A significant decrease in GAGs was observed during the ageing process.CSs are affected at both the structural and quantitative levels with important changes in sulfation observed upon maturity,which correlated with a decrease in the expression of both XT-I and GT-I.A progressive switch of the sulfation profile was noted in both NP and AF tissues from 6 months to 8 years.These changes give an appreciation of the potential impact of CSs on the disc biology and the development of therapeutic approaches for disc regeneration and repair.
基金This research was supported by the National Natural Science Foundation of China(Grant no.32071351,81772400 and 31900583,32071341)the Fundamental Research Funds for the Central Universities(Grant no.19ykzd05)+3 种基金the Committee for Science and Technology Innovation of Shenzhen(Grant no.JCYJ20190809142211354 and GJHZ20180929160004704)the Sanming Project of Medicine in Shenzhen(Grant no.SZSM201911002)the Natural Science Foundation of Guangzhou City(Grant no.201807010031,201704030082)the Beijing Municipal Health Commission(Grant no.BMHC-2019-9,BMHC-2018-4,PXM2020_026275_000002).
文摘It has been proven that the mechanical microenvironment can impact the differentiation of mesenchymal stem cells(MSCs).However,the effect of mechanical stimuli in biofabricating hydroxyapatite scaffolds on the inflammatory response of MSCs remains unclear.This study aimed to investigate the effect of mechanical loading on the inflammatory response of MSCs seeded on scaffolds.Cyclic mechanical loading was applied to biofabricate the cell-scaffold composite for 15 min/day over 7,14,or 21 days.At the predetermined time points,culture supernatant was collected for inflammatory mediator detection,and gene expression was analyzed by qRT-PCR.The results showed that the expression of inflammatory mediators(IL1B and IL8)was downregulated(p<0.05)and the expression of ALP(p<0.01)and COL1A1(p<0.05)was upregulated under mechanical loading.The cell-scaffold composites biofabricated with or without mechanical loading were freeze-dried to prepare extracellular matrix-based scaffolds(ECM-based scaffolds).Murine macrophages were seeded on the ECM-based scaffolds to evaluate their polarization.The ECM-based scaffolds that were biofabricated with mechanical loading before freeze-drying enhanced the expression of M2 polarization-related biomarkers(Arginase 1 and Mrc1,p<0.05)of macrophages in vitro and increased bone volume/total volume ratio in vivo.Overall,these findings demonstrated that mechanical loading could dually modulate the inflammatory responses and osteogenic differentiation of MSCs.Besides,the ECM-based scaffolds that were biofabricated with mechanical loading before freeze-drying facilitated the M2 polarization of macrophages in vitro and bone regeneration in vivo.Mechanical loading may be a promising biofabrication strategy for bone biomaterials.
基金This study was supported by the National Key R&D Program of China(Grant no.2017YFC1105000)the National Natural Science Foundation of China(Grant no.81772400,31900583,31430030)+4 种基金the Fundamental Research Funds for the Central Universities(Grant no.19ykzd05)the Natural Science Foundation of Guangzhou City(Grant no.201704030082,201807010031)the Foundation of Shenzhen Committee for Science and Technology Innovation(Grant no.JCYJ20190809142211354,GJHZ20180929160004704)the Sanming Project of Medicine in Shenzhen(Grant no.SZSM201911002)and the Beijing Municipal Health Commission(Grant no.BMHC-2021-X,BMHC-2019-9,BMHC-2018-4,PXM2020_026275_000002).Special thanks are extended to Dr.Cheng Ruijuan for technical support.
文摘The osteogenic microenvironment of bone-repairing materials plays a key role in accelerating bone regeneration but remains incompletely defined,which significantly limits the application of such bioactive materials.Here,the transcriptional landscapes of different osteogenic microenvironments,including three-dimensional(3D)hydroxyapatite(HA)scaffolds and osteogenic medium(OM),for mesenchymal stromal cells(MSCs)in vitro were mapped at single-cell resolution.Our findings suggested that an osteogenic process reminiscent of endochondral ossification occurred in HA scaffolds through sequential activation of osteogenic-related signaling pathways,along with inflammation and angiogenesis,but inhibition of adipogenesis and fibrosis.Moreover,we revealed the mechanism during OM-mediated osteogenesis involves the ZBTB16 and WNT signaling pathways.Heterogeneity of MSCs was also demonstrated.In vitro ossification of LRRC75A+MSCs was shown to have better utilization of WNT-related ossification process,and PCDH10+MSCs with superiority in hydroxyapatite-related osteogenic process.These findings provided further understanding of the cellular activity modulated by OM conditions and HA scaffolds,providing new insights for the improvement of osteogenic biomaterials.This atlas provides a blueprint for research on MSC heterogeneity and the osteogenic microenvironment of HA scaffolds and a database reference for the application of bioactive materials for bone regeneration.