M2 Macrophage-Derived Small Extracellular Vesicles Ameliorate Pyroptosis and Intervertebral Disc Degeneration.

Intervertebral discs (IVDs) have a limited self-regenerative capacity and current strategies for IVD regeneration are unsatisfactory. Recent studies showed that small extracellular vesicles derived from M2 macrophage cells (M2-sEVs) inhibited inflammation by delivery of various bioactive molecules to recipient cells, which indicated that M2-sEVs may offer a therapeutic strategy for the repair of IVDs. Herein, we investigated the roles and mechanisms of M2-sEVs on IVD regeneration. The in vitro results demonstrated that M2-sEVs inhibited pyroptosis, preserved cellular viability, and promoted migration of nucleus pulposus cells (NPCs). Bioinformatics analysis and verification experiments of microRNA (miR) expression showed that miR-221-3p was highly expressed in M2-sEVs. The mechanism of action was explored and indicated that M2-sEVs inhibited pyroptosis of NPCs through transfer of miR-221-3p, which suppressed the expression levels of phosphatase and tensin homolog and NOD-, LRR-, and pyrin domain-containing protein 3. Moreover, we fabricated decellularized ECM-hydrogel (dECM) for sustained release of M2-sEVs, which exhibited biocompatibility and controlled release properties. The in vivo results revealed that dECM-hydrogel containing M2-sEVs (dECM/M2-sEVs) delayed the degeneration of intervertebral disc degeneration (IDD) models. In addition to demonstrating a promising therapeutic for IDD, this study provided valuable data for furthering the understanding of the roles and mechanisms of M2-sEVs in IVD regeneration.

Elastic porous microspheres/extracellular matrix hydrogel injectable composites releasing dual bio-factors enable tissue regeneration.

Injectable biomaterials have garnered increasing attention for their potential and beneficial applications in minimally invasive surgical procedures and tissue regeneration. Extracellular matrix (ECM) hydrogels and porous synthetic polymer microspheres can be prepared for injectable administration to achieve in situ tissue regeneration. However, the rapid degradation of ECM hydrogels and the poor injectability and biological inertness of most polymeric microspheres limit their pro-regenerative capabilities. Here, we develop a biomaterial system consisting of elastic porous poly(l-lactide-co-ε-caprolactone) (PLCL) microspheres mixed with ECM hydrogels as injectable composites with interleukin-4 (IL-4) and insulin-like growth factor-1 (IGF-1) dual-release functionality. The developed multifunctional composites have favorable injectability and biocompatibility, and regulate the behavior of macrophages and myogenic cells following injection into muscle tissue. The elicited promotive effects on tissue regeneration are evidenced by enhanced neomusle formation, vascularization, and neuralization at 2-months post-implantation in a male rat model of volumetric muscle loss. Our developed system provides a promising strategy for engineering bioactive injectable composites that demonstrates desirable properties for clinical use and holds translational potential for application as a minimally invasive and pro-regenerative implant material in multiple types of surgical procedures.

Micro-nanofiber composite biomimetic conduits promote long-gap peripheral nerve regeneration in canine models.

Peripheral nerve injuries may result in severe long-gap interruptions that are challenging to repair. Autografting is the gold standard surgical approach for repairing long-gap nerve injuries but can result in prominent donor-site complications. Instead, imitating the native neural microarchitecture using synthetic conduits is expected to offer an alternative strategy for improving nerve regeneration. Here, we designed nerve conduits composed of high-resolution anisotropic microfiber grid-cordes with randomly organized nanofiber sheaths to interrogate the positive effects of these biomimetic structures on peripheral nerve regeneration. Anisotropic microfiber-grids demonstrated the capacity to directionally guide Schwann cells and neurites. Nanofiber sheaths conveyed adequate elasticity and permeability, whilst exhibiting a barrier function against the infiltration of fibroblasts. We then used the composite nerve conduits bridge 30-mm long sciatic nerve defects in canine models. At 12 months post-implant, the morphometric and histological recovery, gait recovery, electrophysiological function, and degree of muscle atrophy were assessed. The newly regenerated nerve tissue that formed within the composite nerve conduits showed restored neurological functions that were superior compared to sheaths-only scaffolds and Neurolac nerve conduit controls. Our findings demonstrate the feasibility of using synthetic biophysical cues to effectively bridge long-gap peripheral nerve injuries and indicates the promising clinical application prospects of biomimetic composite nerve conduits.

M2 Macrophage-Derived sEV Regulate Pro-Inflammatory CCR2+ Macrophage Subpopulations to Favor Post-AMI Cardiac Repair.

Tissue-resident cardiac macrophage subsets mediate cardiac tissue inflammation and repair after acute myocardial infarction (AMI). CC chemokine receptor 2 (CCR2)-expressing macrophages have phenotypical similarities to M1-polarized macrophages, are pro-inflammatory, and recruit CCR2+ circulating monocytes to infarcted myocardium. Small extracellular vesicles (sEV) from CCR2̶ macrophages, which phenotypically resemble M2-polarized macrophages, promote anti-inflammatory activity and cardiac repair. Here, the authors harvested M2 macrophage-derived sEV (M2EV ) from M2-polarized bone-marrow-derived macrophages for intramyocardial injection and recapitulation of sEV-mediated anti-inflammatory activity in ischemic-reperfusion (I/R) injured hearts. Rats and pigs received sham surgery; I/R without treatment; or I/R with autologous M2EV treatment. M2EV rescued cardiac function and attenuated injury markers, infarct size, and scar size. M2EV inhibited CCR2+ macrophage numbers, reduced monocyte-derived CCR2+ macrophage recruitment to infarct sites, induced M1-to-M2 macrophage switching and promoted neovascularization. Analysis of M2EV microRNA content revealed abundant miR-181b-5p, which regulated macrophage glucose uptake, glycolysis, and mitigated mitochondrial reactive oxygen species generation. Functional blockade of miR-181b-5p is detrimental to beneficial M2EV actions and resulted in failure to inhibit CCR2+ macrophage numbers and infarct size. Taken together, this investigation showed that M2EV rescued myocardial function, improved myocardial repair, and regulated CCR2+ macrophages via miR-181b-5p-dependent mechanisms, indicating an option for cell-free therapy for AMI.

Reciprocal interaction between vascular niche and sweat gland promotes sweat gland regeneration.

The incorporation of vasculature is known to be effective in tissue or organ functional regeneration. However, a vague understanding of the interaction between epidermal appendages and their vascular niches is a foremost obstacle to obtaining sweat gland (SG)-specific vasculature units. Here, we map their precise anatomical connections and report that the interplay between SG cells (SGCs) and the surrounding vascular niche is key for glandular development and homeostasis maintenance. To replicate this interplay in vitro, we used three-dimensional (3D) bioprinting to generate reproducible SGC spheroids from differentiated adipose-derived mesenchymal stem cells (ADSCs). With dermal microvascular endothelial cells (DMECs), sacrificial templates made from poly (ε-caprolactone) (PCL) were fabricated to pattern the vascular niche. This interplay model promoted physiologically relevant vascularized glandular morphogenesis in vitro and in vivo. We identified a reciprocal regulatory mechanism for promoting SGs regeneration via contact-independent cell communication and direct cell-cell interactions between SGs and the vasculature. We envision the successful use of our approach for vascularized organ regeneration in the near future.

Immunomodulatory hybrid micro-nanofiber scaffolds enhance vascular regeneration.

The inertness of synthetic polymer materials and the insufficient mechanical strength of reprocessed decellularized extracellular matrix (dECM) limited their promotive efforts on tissue regeneration. Here, we prepared a hybrid scaffold composed of PCL microfibers and human placental extracellular matrix (pECM) nanofibers by co-electrospinning, which was grafted with heparin and further absorbed with IL-4. The hybrid scaffold with improved hemocompatibility firstly switched macrophages to anti-inflammatory phenotype (increased by 18.1%) and then promoted migration, NO production, tube formation of endothelial cells (ECs), and migration and maturation of vascular smooth muscle cells (VSMCs), and ECM deposition in vitro and in vivo. ECs coverage rate increased by 8.6% and the thickness of the smooth muscle layer was 1.8 times more than PCL grafts at 12 wks. Our study realized the complementary advantages of synthetic polymer materials and dECM materials, and opened intriguing perspectives for the design and construction of small-diameter vascular grafts (SDVGs) and immune-regulated materials for other tissue regeneration.

Progress in methods for evaluating Schwann cell myelination and axonal growth in peripheral nerve regeneration via scaffolds.

Peripheral nerve injury (PNI) is a neurological disorder caused by trauma that is frequently induced by accidents, war, and surgical complications, which is of global significance. The severity of the injury determines the potential for lifelong disability in patients. Artificial nerve scaffolds have been investigated as a powerful tool for promoting optimal regeneration of nerve defects. Over the past few decades, bionic scaffolds have been successfully developed to provide guidance and biological cues to facilitate Schwann cell myelination and orientated axonal growth. Numerous assessment techniques have been employed to investigate the therapeutic efficacy of nerve scaffolds in promoting the growth of Schwann cells and axons upon the bioactivities of distinct scaffolds, which have encouraged a greater understanding of the biological mechanisms involved in peripheral nerve development and regeneration. However, it is still difficult to compare the results from different labs due to the diversity of protocols and the availability of innovative technologies when evaluating the effectiveness of novel artificial scaffolds. Meanwhile, due to the complicated process of peripheral nerve regeneration, several evaluation methods are usually combined in studies on peripheral nerve repair. Herein, we have provided an overview of the evaluation methods used to study the outcomes of scaffold-based therapies for PNI in experimental animal models and especially focus on Schwann cell functions and axonal growth within the regenerated nerve.

Association of Gut Microbiota Composition in Pregnant Women Colonized with Group B Streptococcus with Maternal Blood Routine and Neonatal Blood-Gas Analysis.

Group B Streptococcus (GBS) colonizes the vaginal and rectal mucosa in a substantial proportion of healthy women, and GBS is a risk factor for GBS-associated adverse birth outcomes, such as bacterial infection, in neonates. Whether changes in the gut microbiota of GBS-infected pregnant women are associated with maternal complete blood cell count (CBC) and neonatal blood-gas analysis is unknown. To explore the relationship between the intestinal microecological composition of pregnant women and maternal blood routine and neonatal blood-gas analysis, we collected intestinal microecology samples of 26 pregnant women in clinic. They were divided into a positive group(GBS positive,GBS +) and a negative group (GBS negative, GBS-), with 12 in the positive group and 14 in the negative group. 16S rRNA gene sequencing was used to examine the gut microbiota profile from a fecal sample of pregnant women. CBC was carried out in enrolled pregnant women and umbilical arterial blood-gas analysis (UABGA)was conducted for analysis of intestinal microbiota composition, maternal blood routine and neonatal blood gas. Our results showed significant differences in the total number of organisms and microbial diversity of intestinal microbiota between healthy pregnant women and GBS-positive pregnant women. Particularly, abundances of Lentisphaerae, Chlorobi, Parcubacteria, Chloroflexi, Gemmatimonadetes, Acidobacteria, Fusobacteria and Fibrobacteres were only detected in participants with GBS colonization. Blood-gas analysis revealed that neonates born to mothers with GBS colonization had significantly higher fractions of carboxyhemoglobin (FCOHb) and lower methemoglobin (FMetHb), and abundances of OTU80, OTU122, OTU518 and OTU375 were associated with blood-gas indicators, such as carboxyhemoglobin, methemoglobin, PCO2, PH and ABE. Interestingly, there were significant correlations between OTU levels and inflammatory indexes in pregnant women with GBS infection. Together, this study revealed for the first time that altered gut microbiota compositions are related to the inflammatory state in GBS-positive pregnant women and neonatal blood-gas indicators. GBS colonization may lead to significant changes in the gut microbiome, which might be involved in the pathogenesis of the maternal inflammatory state and neonatal blood gas abnormalities.

Fabrication of high-strength, flexible, porous collagen-based scaffolds to promote tissue regeneration.

Collagen-based scaffolds lack mechanical strength, flexibility, and tunable pore structure, affecting tissue repair outcomes and restricting their wide clinical application. Here, two kinds of scaffolds were prepared by a combination of vacuum homogenization, natural air drying, water soaking, lyophilization, and crosslinking. Compared with the scaffolds made of collagen molecules (Col-M), the scaffolds made of collagen aggregates (Col-A) exhibited higher mechanical strength (ultimate tensile strength: 1.38 â€‹± â€‹0.26 â€‹MPa vs 15.46 â€‹± â€‹1.55 â€‹MPa), stronger flexibility, advanced cell adhesion, survival, and proliferation. Subcutaneous implantation in rats showed that Col-A scaffolds promoted cell infiltration, macrophage polarization, and vascularization. Furthermore, the Col-A scaffolds inhibited abdominal bulges due to their adequate mechanical support, and they also promoted vascularized muscle regeneration in a rat abdominal hernia defect model. Our study provides a novel strategy for generating high-strength, flexible, porous collagen-based scaffolds, which can be applied to tissue repair with mechanical strength requirements. It broadens their application range in the field of regenerative medicine.

Fabrication of channeled scaffolds through polyelectrolyte complex (PEC) printed sacrificial templates for tissue formation.

One of the pivotal factors that limit the clinical translation of tissue engineering is the inability to create large volume and complex three-dimensional (3D) tissues, mainly due to the lack of long-range mass transport with many current scaffolds. Here we present a simple yet robust sacrificial strategy to create hierarchical and perfusable microchannel networks within versatile scaffolds via the combination of embedded 3D printing (EB3DP), tunable polyelectrolyte complexes (PEC), and casting methods. The sacrificial templates of PEC filaments (diameter from 120 to 500 µm) with arbitrary 3D configurations were fabricated by EB3DP and then incorporated into various castable matrices (e.g., hydrogels, organic solutions, meltable polymers, etc.). Rapid dissolution of PEC templates within a 2.00 M potassium bromide aqueous solution led to the high fidelity formation of interconnected channels for free mass exchange. The efficacy of such channeled scaffolds for in vitro tissue formation was demonstrated with mouse fibroblasts, showing continuous cell proliferation and ECM deposition. Subcutaneous implantation of channeled silk fibroin (SF) scaffolds with a porosity of 76% could lead to tissue ingrowth as high as 53% in contrast to 5% for those non-channeled controls after 4 weeks. Both histological and immunofluorescence analyses demonstrated that such channeled scaffolds promoted cellularization, vascularization, and host integration along with immunoregulation.

Tri-Layered Vascular Grafts Guide Vascular Cells' Native-like Arrangement.

Bionic grafts hold great promise for directing tissue regeneration. In vascular tissue engineering, although a large number of synthetic grafts have been constructed, these substitutes only partially recapitulated the tri-layered structure of native arteries. Synthetic polymers such as poly(l-lactide-co-ε-caprolactone) (PLCL) possess good biocompatibility, controllable degradation, remarkable processability, and sufficient mechanical strength. These properties of PLCL show great promise for fabricating synthetic vascular substitutes. Here, tri-layered PLCL vascular grafts (TVGs) composed of a smooth inner layer, circumferentially aligned fibrous middle layer, and randomly distributed fibrous outer layer were prepared by sequentially using ink printing, wet spinning, and electrospinning techniques. TVGs possessed kink resistance and sufficient mechanical properties (tensile strength, elastic modulus, suture retention strength, and burst pressure) equivalent to the gold standard conduits of clinical application, i.e., human saphenous veins and human internal mammary arteries. The stratified structure of TVGs exhibited a visible guiding effect on specific vascular cells including enhancing endothelial cell (EC) monolayer formation, favoring vascular smooth muscle cells' (VSMCs) arrangement and elongation, and facilitating fibroblasts' proliferation and junction establishment. Our research provides a new avenue for designing synthetic vascular grafts with polymers.

Mechanically reinforced biotubes for arterial replacement and arteriovenous grafting inspired by architectural engineering.

There is a lack in clinically-suitable vascular grafts. Biotubes, prepared using in vivo tissue engineering, show potential for vascular regeneration. However, their mechanical strength is typically poor. Inspired by architectural design of steel fiber reinforcement of concrete for tunnel construction, poly(ε-caprolactone) (PCL) fiber skeletons (PSs) were fabricated by melt-spinning and heat treatment. The PSs were subcutaneously embedded to induce the assembly of host cells and extracellular matrix to obtain PS-reinforced biotubes (PBs). Heat-treated medium-fiber-angle PB (hMPB) demonstrated superior performance when evaluated by in vitro mechanical testing and following implantation in rat abdominal artery replacement models. hMPBs were further evaluated in canine peripheral arterial replacement and sheep arteriovenous graft models. Overall, hMPB demonstrated appropriate mechanics, puncture resistance, rapid hemostasis, vascular regeneration, and long-term patency, without incidence of luminal expansion or intimal hyperplasia. These optimized hMPB properties show promise as an alternatives to autologous vessels in clinical applications.

Microchannelled alkylated chitosan sponge to treat noncompressible hemorrhages and facilitate wound healing.

Developing an anti-infective shape-memory hemostatic sponge able to guide in situ tissue regeneration for noncompressible hemorrhages in civilian and battlefield settings remains a challenge. Here we engineer hemostatic chitosan sponges with highly interconnective microchannels by combining 3D printed microfiber leaching, freeze-drying, and superficial active modification. We demonstrate that the microchannelled alkylated chitosan sponge (MACS) exhibits the capacity for water and blood absorption, as well as rapid shape recovery. We show that compared to clinically used gauze, gelatin sponge, CELOX™, and CELOX™-gauze, the MACS provides higher pro-coagulant and hemostatic capacities in lethally normal and heparinized rat and pig liver perforation wound models. We demonstrate its anti-infective activity against S. aureus and E. coli and its promotion of liver parenchymal cell infiltration, vascularization, and tissue integration in a rat liver defect model. Overall, the MACS demonstrates promising clinical translational potential in treating lethal noncompressible hemorrhage and facilitating wound healing.

Construction of chitosan scaffolds with controllable microchannel for tissue engineering and regenerative medicine.

Microchannels are effective means of enabling the functional performance of tissue engineering scaffolds. Chitosan, a partial deacetylation derivative of chitin, exhibiting excellent biocompatibility, has been widely used in clinical practice. However, development of chitosan scaffolds with controllable microchannels architecture remains an engineering challenge. Here, we generated chitosan scaffolds with adjustable microchannel by combining a 3D printing microfiber templates-leaching method and a freeze-drying method. We can precisely control the arrangement, diameter and density of microchannel within chitosan scaffolds. Moreover, the integrated bilayer scaffolds with the desired structural parameters in each layer were fabricated and exhibited no delamination. The flow rate and volume of the simulated fluid can be modulated by diverse channels architecture. Additionally, the microchannel structure promoted cell survival, proliferation and distribution in vitro, and improved cell and tissue ingrowth and vascular formation in vivo. This study opens a new road for constructing chitosan scaffolds, and can further extend their application scope across tissue engineering and regenerative medicine.

Highly interconnected inverse opal extracellular matrix scaffolds enhance stem cell therapy in limb ischemia.

The therapeutic effectiveness of cell transplantation in treatment of diseases and injuries is often limited by low cell retention, survivability, and engraftment. Extracellular matrix (ECM)-derived scaffolds are capable of controlling cell responses, thereby offering potential solutions to current challenges associated with cell therapy. However, it remains a technical challenge to produce ECM scaffolds with highly interconnected porous structure specifically required for cell transplantation. Here, we developed inverse opal porous extracellular matrix (ioECM) scaffolds through subcutaneous implantation of sacrificial templates assembled from polymer microspheres, followed by removal of the microsphere template and cellular content. Such highly interconnected porous ioECM scaffolds supported the anchorage, survival, viability, anti-apoptotic and paracrine activities of rat bone marrow mesenchymal stem cells (BMSCs), which further promoted endothelial cell migration and tube formation and viability. Upon transplantation into nude mouse critical limb ischemic model, ioECM promoted the engraftment of laden BMSCs, facilitated interconnected vascular network formation with accelerated recovery of blood perfusion and inhibited muscle atrophy and fibrosis. Our study demonstrates a unique strategy to engineer highly porous yet well-interconnected ECM scaffolds specifically for cell transplantation with marked improvement of survivability and vascularization, which offers an essential step toward the success of cell therapy and regenerative medicine. STATEMENT OF SIGNIFICANCE: Cell-based therapy has a good developing foreground applied in a variety of tissue regeneration. Extracellular matrix (ECM) scaffolds is an optimal choice for cell delivery duo to its superior biocompatibility and favorable immune responses. However, the current ECM scaffolds lacking of the controllable pore structure restrict the cell delivery efficiency and therapeutic outcome. Here, we fabricated highly interconnected inverse opal extracellular matrix (ioECM) scaffolds, which can enhance the effect of stem cell therapy in limb ischemic model by improving the survival, viability, and paracrine activities of stem cells. Our study provides reference value for the design and fabrication of ECM based biomaterials for cell transplantation.

Aligned microfiber-induced macrophage polarization to guide schwann-cell-enabled peripheral nerve regeneration.

Mechanistic understanding of the topological cues delivered by biomaterials in promotion of oriented tissue regeneration (e.g., peripheral nerve regrowth) remains largely elusive. Here, we engineered nerve conduits composed of oriented microfiber-bundle cores and randomly organized nanofiber sheaths to particularly interrogate the regulatory mechanism of microfiber orientation on promoted peripheral nerve regeneration. With comprehensive yet systematic analyses, we were able to elucidate the intricate cascade of biological responses associated with conduit-assisted nerve regrowth, i.e., oriented microfibers facilitated macrophage recruitment and subsequent polarization toward a pro-healing phenotype, which in turn promoted Schwann cell (SC) migration, myelinization and axonal extension. Pronounced improvement of nerve regeneration in rat sciatic nerve injury was evidenced with enhanced electrophysiologic function, sciatic functional index and alleviated muscle atrophy 3 months post-implantation. The obtained results offer essential insights on the topological regulation of biomaterials in functional nerve tissue regeneration via immune modulation.

Targeted Repair of Vascular Injury by Adipose-Derived Stem Cells Modified with P-Selectin Binding Peptide.

Percutaneous coronary intervention for coronary artery disease treatment often results in pathological vascular injury, characterized by P-selectin overexpression. Adipose-derived stem cells (ADSCs) therapeutic efficacy remains elusive due to poor ADSCs targeting and retention in injured vessels. Here, conjugated P-selectin binding peptide (PBP) to polyethylene glycol-conjugated phospholipid derivative (DMPE-PEG) linkers (DMPE-PEG-PBP; DPP) are used to facilitate the modification of PBP onto ADSCs cell surfaces via hydrophobic interactions between DMPE-PEG and the phospholipid bilayer. DPP modification neither has influence on ADSCs proliferation nor apoptosis/paracrine factor gene expression. A total of 5 × 10-6 m DPP-modified ADSCs (DPP-ADSCs) strongly binds to P-selectin-displaying activated platelets and endothelial cells (ECs) in vitro and to wire-injured rat femoral arteries when administered by intra-arterial injection. Targeted binding of ADSCs shields injury sites from platelet and leukocyte adhesion, thereby decreasing inflammation at injury sites. Furthermore, targeted binding of ADSCs recovers injured ECs functionality and reduces platelet-initiated vascular smooth muscle cells (VSMCs) chemotactic migration. Targeted binding of DPP-human ADSCs to balloon-injured human femoral arteries is also demonstrated in ex vivo experiments. Overall, DPP-ADSCs promote vascular repair, inhibit neointimal hyperplasia, increase endothelium functionality, and maintain normal VSMCs alignment, supporting preclinical noninvasive utilization of DPP-ADSCs for vascular injury.

Construction of vascular graft with circumferentially oriented microchannels for improving artery regeneration.

Design and fabrication of scaffolds with three-dimensional (3D) topological cues inducing regeneration of the neo-tissue comparable to native one remains a major challenge in both scientific and clinical fields. Here, we developed a well-designed vascular graft with 3D highly interconnected and circumferentially oriented microchannels by using the sacrificial sugar microfiber leaching method. The microchannels structure was capable of promoting the migration, oriented arrangement, elongation, and the contractile phenotype expression of vascular smooth muscle cells (VSMCs) in vitro. After implantation into the rat aorta defect model, the microchannels in vascular grafts simultaneously improved the infiltration and aligned arrangement of VSMCs and the oriented deposition of extracellular matrix (ECM), as well as the recruitment and polarization of macrophages. These positive results also provided protection and support for ECs growth, and ultimately accelerated the endothelialization. Our research provides a new strategy for the fabrication of grafts with the capability of inducing arterial regeneration, which could be further extended to apply in preparing other kinds of oriented scaffolds aiming to guide oriented tissue in situ regeneration.

Role of the Calcified Cartilage Layer of an Integrated Trilayered Silk Fibroin Scaffold Used to Regenerate Osteochondral Defects in Rabbit Knees.

The repair of osteochondral defects remains challenging, given the complexity of native osteochondral tissue and the limited self-repair capacity of cartilage. Osteochondral tissue engineering is a promising strategy. Here, we fabricated a biomimetic osteochondral scaffold using silk fibroin and hydroxyapatite, including a calcified cartilage layer (CCL). We studied the role played by the CCL in terms of cell viability in vivo. We established osteochondral defects in rabbit knees to investigate the effects of CCL-containing scaffolds with or without adipose tissue-derived stem cells (ADSCs). We evaluated osteochondral tissue regeneration by calculating gross observational scores, via histological and immunohistochemical assessments, by performing quantitative biochemical and biomechanical analyses of new osteochondral tissue, and via microcomputed tomography of new bone at 4, 8, and 12 weeks after surgery. In terms of surface roughness and integrity, the CCL + ADSCs group was better than the CCL and the non-CCL + ADSCs groups at all time points tested; the glycosaminoglycan and collagen type II levels of the CCL + ADSCs group were highest, reflecting the important role played by the CCL in cartilage tissue repair. Subchondral bone smoothness was better in the CCL + ADSCs group than in the non-CCL + ADSCs and CCL groups. The CCL promoted smooth subchondral bone regeneration but did not obviously affect bone strength or quality. In conclusion, a biomimetic osteochondral scaffold with a CCL, combined with autologous ADSCs, satisfactorily regenerated a rabbit osteochondral defect. The CCL enhances cartilage and subchondral bone regeneration.

Behavioral and dietary risk factors of recurrent urinary tract infection in Chinese postmenopausal women: a case-control study.

OBJECTIVE: The present study aimed to examine the behavioral and dietary risk factors of recurrent urinary tract infection (RUTI) in postmenopausal patients in China. METHODS: We performed a population-based case-control study with 193 postmenopausal women with RUTI and 193 age-matched healthy female controls with no history of RUTI. The study was conducted between January 2016 and June 2018 in Changzhou, China. Data were collected using an interviewer-based questionnaire, including information on demographics, lifestyle behavior, and habitual diet. Conditional logistic regression analysis was conducted to examine the risk factors associated with RUTI. RESULTS: Wiping from back to front after toilet use, sedentary behavior >6 hours/day, delayed voiding, and chronic constipation were associated with an increased risk of RUTI. Drinking more than three cups of green tea per month showed an inverse association with RUTI. However, there was no evidence of dose dependency for overall consumption. Additionally, the three-cup association involved a small proportion of cases and may reflect statistical artifact. CONCLUSIONS: Wiping from back to front after toilet use, sedentary behavior, delayed voiding, and chronic constipation are associated with an increased risk of RUTI in postmenopausal women.