Effects of calcium phosphate and phosphorus-dissolving bacteria on microbial structure and function during Torreya Grandis branch waste composting.

BACKGROUND BURKHOLDERIA: is a phosphorus solubilizing microorganism discovered in recent years, which can dissolve insoluble phosphorus compounds into soluble phosphorus. To investigate the effects of Burkholderia and calcium phosphate on the composting of Torreya grandis branches and leaves, as well as to explain the nutritional and metabolic markers related to the composting process. METHODS: In this study, we employed amplicon sequencing and untargeted metabolomics analysis to examine the interplay among phosphorus (P) components, microbial communities, and metabolites during T. grandis branch and leaf waste composting that underwent treatment with calcium phosphate and phosphate-solubilizing bacteria (Burkholderia). There were four composting treatments, 10% calcium phosphate (CaP) or 5 ml/kg (1 × 108/ml Burkholderia) microbial inoculum (WJP) or both (CaP + WJP), and the control group (CK). RESULTS: The results indicated that Burkholderia inoculation and calcium phosphate treatment affected the phosphorus composition, pH, EC, and nitrogen content. Furthermore, these treatments significantly affected the diversity and structure of bacterial and fungal communities, altering microbial and metabolite interactions. The differential metabolites associated with lipids and organic acids and derivatives treated with calcium phosphate treatment are twice as high as those treated with Burkholderia in both 21d and 42d. The results suggest that calcium phosphate treatment alters the formation of some biological macromolecules. CONCLUSION: Both Burkholderia inoculation and calcium phosphate treatment affected the phosphorus composition, nitrogen content and metabolites of T. grandis branch and leaf waste compost.These results extend our comprehension of the coupling of matter transformation and community succession in composting with the addition of calcium phosphate and phosphate-solubilizing bacteria.

The impact of the physicochemical properties of calcium phosphate ceramics on biocompatibility and osteogenic differentiation of mesenchymal stem cells.

OBJECTIVE: In this study we have focused on biocompatibility and osteoinductive capacity analysis of self-manufactured single-phase (HAP) and two-phase (HAP and ß-ТСР) bioactive ceramics with various chemical modifications (Fig. 1). RESULTS: We demonstrate a reduction in solubility for all analyzed composite after the treatment with H2O and H2O2, accompanied by an enhancement in adsorption activity. This modification also resulted in an increase in micro- and macroporosity, along with a rise in the open porosity. Adipose-derived mesenchymal stromal cells demonstrated excellent cell adhesion and survival when cultured with these ceramics. Calcium phosphate ceramics (H-500, HT-500, and HT-1 series) stimulated alkaline phosphatase expression, promoted calcium deposition, and enhanced osteopontin expression in ADSCs, independently inducing osteogenesis without additional osteogenic stimuli. These findings underscore the promising potential of HAP-based bioceramics for bone regeneration/reconstruction.

Evaluation of efficacy of oral calcium phosphate as an adjunct to standard-of-care regular phototherapy in cases of neonatal jaundice: a hospital-based double-blind, randomised, placebo-controlled trial.

OBJECTIVE: Neonatal jaundice is the most common cause of neonatal morbidity and rehospitalisation in the first week of life, affecting approximately 60% of term and 80% of preterm neonates, with 10% requiring phototherapy to prevent bilirubin-induced neurological dysfunction. Enterohepatic circulation contributes 10%-20% of the body's bilirubin load, and oral calcium-phosphate can inhibit this process by binding to unconjugated bilirubin and acting as a bilirubin-trapping agent in the gut. This study aimed to evaluate the efficacy of oral calcium phosphate as an adjunct to phototherapy in reducing phototherapy duration, improving bilirubin decline rate and lowering rebound hyperbilirubinaemia incidence. METHODS: This double-blind, placebo-controlled randomised controlled trial with a 1:1 allocation ratio was conducted in the neonatal intensive care unit of a tertiary care hospital in Eastern India. The investigator and the analyst were blinded to the treatment assignments. Eligible neonates with neonatal jaundice requiring phototherapy as per the 'American Academy of Pediatrics or 'National Institute for Health and Care Excellence' guidelines were enrolled and randomly assigned to receive either oral calcium phosphate or placebo. RESULTS: The total duration of phototherapy was significantly lower in the intervention group compared with placebo (18.8±5.63 hours vs 24.3±4.50 hours; mean difference=-5.55 (95% CI -7.82 to -3.28), p<0.001). The rate of fall of bilirubin (mg/dL/hour) was also significantly higher in the intervention group (0.186±0.0137 vs 0.116±0.0088; mean difference=0.0693 (95% CI 0.0642 to 0.0745), p<0.001). The intervention group showed a trend towards a decrease in the incidence of rebound hyperbilirubinaemia, with a relative risk of 0.30 ((95% CI 0.0891 to 1.01), p=0.066). CONCLUSION: The use of oral calcium phosphate results in a statistically significant reduction in phototherapy hours, an improvement in the rate of bilirubin decline and a decrease in rebound hyperbilirubinaemia incidence. This allows for shorter hospital stays and reduces the need for rehospitalisation, resulting in less mother-baby dyad separation, lower hospital resource consumption and reduced financial burden on parents. TRIAL REGISTRATION NUMBER: Clinical-trials-registry-India, Ref No.CTRI/2022/03/041203, dated 21 March 2022https://ctri.nic.in/Clinicaltrials/showallp.php?mid1=57944&EncHid=&userName=Phototherapy.

Potential role of calcium sulfate/ß-tricalcium phosphate/graphene oxide nanocomposite for bone graft application_mechanical and biological analyses.

BACKGROUND: Bone grafts are extensively used for repairing bone defects and voids in orthopedics and dentistry. Moldable bone grafts offer a promising solution for treating irregular bone defects, which are often difficult to fill with traditional rigid grafts. However, practical applications have been limited by insufficient mechanical strength and rapid degradation. METHODS: This study developed a ceramic composite bone graft composed of calcium sulfate (CS), ß-tricalcium phosphate (ß-TCP) with/without graphene oxide (GO) nano-particles. The biomechanical properties, degradation rate, and in-vitro cellular responses were investigated. In addition, the graft was implanted in-vivo in a critical-sized calvarial defect model. RESULTS: The results showed that the compressive strength significantly improved by 135% and the degradation rate slowed by 25.5% in comparison to the control model. The addition of GO nanoparticles also improved cell compatibility and promoted osteogenic differentiation in the in-vitro cell culture study and was found to be effective at promoting bone repair in the in-vivo animal model. CONCLUSIONS: The mixed ceramic composites presented in this study can be considered as a promising alternative for bone graft applications.

New Insights Into Application Relevant Properties of Cu2+-Doped Brushite Cements.

Doping of brushite cements with metal ions can entail many positive effects on biological and physicochemical properties. Cu2+ ions are known to exhibit antibacterial properties and can additionally have different positive effects on cells as trace elements, whereas high Cu2+ concentrations are cytotoxic. For therapeutical applications of bone cement, a combination of good biocompatibility and sufficient mechanical properties is required. Therefore, the aim of this study was to investigate different physicochemical and biological aspects, relevant for application, of a brushite cement with Cu2+-doped ß-tricalcium phosphate, monocalcium phosphate monohydrate and phytic acid as setting retarder. Additionally, the ion release was compared with a cement with citric acid as setting retarder. The investigated cements showed good injectability coefficients, as well as compressive strength values sufficient for application. Furthermore, no antibacterial effects were detected irrespective of the Cu2+ concentration or the bacterial strain. The cell experiments with eluate samples showed that the viability of MC3T3-E1 cells tended to decrease with increasing Cu2+ concentration in the cement. It is suggested that these biological responses are caused by the difference in the Cu2+ release from the hardened cement depending on the solvent medium. Furthermore, the cements showed a steady release of Cu2+ ions to a lesser extent in comparison with a cement with citric acid as setting retarder, where a burst release of Cu2+ was observed. In conclusion, despite the anticipated antibacterial effect of Cu2+-doped cements was lacking and mammalian cell viability was slightly affected, Cu2+-concentrations maintained the physicochemical properties as well as the compressive strength of cements and the slow ion release from cements produced with phytic acid is considered advantageous compared to citric acid-based formulations.

Magnetically responsive micro-clustered calcium phosphate-reinforced cell-laden microbead sodium alginate hydrogel for accelerated osteogenic tissue regeneration.

The rising prevalence of bone injuries has increased the demand for minimally invasive treatments. Microbead hydrogels, renowned for cell encapsulation, provide a versatile substrate for bone tissue regeneration. They deliver bioactive agents, support cell growth, and promote osteogenesis, aiding bone repair and regeneration. In this study, we synthesized superparamagnetic iron oxide nanoparticles (Sp) coated with a calcium phosphate layer (m-Sp), achieving a distinctive flower-like micro-cluster morphology. Subsequently, sodium alginate (SA) microbead hydrogels containing m-Sp (McSa@m-Sp) were fabricated using a dropping gelation strategy. McSa@m-Sp is magnetically targetable, enhance cross-linking, control degradation rates, and provide strong antibacterial activity. Encapsulation studies with MC3T3-E1 cells revealed enhanced viability and proliferation. These studies also indicated significantly elevated alkaline phosphatase (ALP) activity and mineralization in MC3T3-E1 cells, as confirmed by Alizarin Red S (ARS) and Von Kossa staining, along with increased collagen production within the McSa@m-Sp microbead hydrogels. Immunocytochemistry (ICC) and gene expression studies supported the osteoinductive potential of McSa@m-Sp, showing increased expression of osteogenic markers including RUNX-2, collagen-I, osteopontin, and osteocalcin. Thus, McSa@m-Sp microbead hydrogels offer a promising strategy for multifunctional scaffolds in bone tissue engineering.

The efficiency of two different synthetic bone graft materials on alveolar ridge preservation after tooth extraction: a split-mouth study.

BACKGROUND: Alveolar Bone loss occurs frequently during the first six months after tooth extraction. Various studies have proposed different methods to reduce as much as possible the atrophy of the alveolar ridge after tooth extraction. Filling the socket with biomaterials after extraction can reduce the resorption of the alveolar ridge. We compared the height of the alveolar process at the mesial and distal aspects of the extraction site and the resorption rate was calculated after the application of HA/ß-TCP or synthetic co-polymer polyglycolic - polylactic acid PLGA mixed with blood to prevent socket resorption immediately and after tooth extraction. METHODS: The study was conducted on 24 extraction sockets of impacted mandibular third molars bilaterally, vertically, and completely covered, with a thin bony layer. HA/ß-TCP was inserted into 12 of the dental sockets immediately after extraction, and the synthetic polymer PLGA was inserted into 12 of the dental sockets. All sockets were covered completely with a full-thickness envelope flap. Follow-up was performed for one year after extraction, using radiographs and stents for the vertical alveolar ridge measurements. RESULTS: The mean resorption rate in the HA/ß-TCP and PLGA groups was ± 1.23 mm and ± 0.1 mm, respectively. A minimal alveolar bone height reduction of HA/ß-TCP was observed after 9 months, the reduction showed a slight decrease to 0.93 mm, while this rate was 0.04 mm after 9 months in the PLGA group. Moreover, the bone height was maintained after three months, indicating a good HA/ß-TCP graft performance in preserving alveolar bone (1.04 mm) while this rate was (0.04 mm) for PLGA. CONCLUSION: The PLGA graft demonstrated adequate safety and efficacy in dental socket preservation following tooth extraction. However, HA/ß-TCP causes greater resorption at augmented sites than PLGA, which clinicians should consider during treatment planning.

Three-dimensional printed calcium phosphate scaffolds emulate bone microstructure to promote bone regrowth and repair.

The interconnected structures in a 3D scaffold allows the movement of cells and nutrients. Therefore, this study aimed to investigate the in-vivo bioactivity of 3D-printed ß-tricalcium phosphate (ß-TCP) and hydroxyapatite (HAP) scaffolds that replicate biological bone. This study included 24-week-old male New Zealand white rabbits. A cylindrical bone defect with a diameter of 4.5 mm and a depth of 8 mm was created in the lateral aspect of the distal femur. A 3D-printed scaffold was implanted in the right femur (experimental side), whereas the left femur was kept free of implantation (control side). Micro-CT analysis and histological observations of the bone defect site were conducted at 4, 8, and 12 weeks postoperatively to track the bone repair progress. No evidence of new bone tissue formation was found in the medullary cavity of the bone defect on the control side. In contrast, on the experimental side, the 3D scaffold demonstrated sufficient bioactivity, leading to the growth of new bone tissue. Over time, new bone tissue gradually extended from the periphery toward the center, a phenomenon evident in both micro-CT images and biopsy staining. In the current study, we observed that the cells involved in bone metabolism adhered, spread, and proliferated on our newly designed 3D-printed scaffold with a bone microstructure. Therefore, it is suggested that this scaffold has sufficient bioactivity to induce new bone formation and could be expected to be a more useful artificial bone than the existing version.

Brain-targeted intranasal delivery of protein-based gene therapy for treatment of ischemic stroke.

Gene therapy using a protein-based CRISPR system in the brain has practical limitations due to current delivery systems, especially in the presence of arterial occlusion. To overcome these obstacles and improve stability, we designed a system for intranasal administration of gene therapy for the treatment of ischemic stroke. Methods: Nanoparticles containing the protein-based CRISPR/dCas9 system targeting Sirt1 were delivered intranasally to the brain in a mouse model of ischemic stroke. The CRISPR/dCas9 system was encapsulated with calcium phosphate (CaP) nanoparticles to prevent them from being degraded. They were then conjugated with ß-hydroxybutyrates (bHb) to target monocarboxylic acid transporter 1 (MCT1) in nasal epithelial cells to facilitate their transfer into the brain. Results: Human nasal epithelial cells were shown to uptake and transfer nanoparticles to human brain endothelial cells with high efficiency in vitro. The intranasal administration of the dCas9/CaP/PEI-PEG-bHb nanoparticles in mice effectively upregulated the target gene, Sirt1, in the brain, decreased cerebral edema and increased survival after permanent middle cerebral artery occlusion. Additionally, we observed no significant in vivo toxicity associated with intranasal administration of the nanoparticles, highlighting the safety of this approach. Conclusion: This study demonstrates that the proposed protein-based CRISPR-dCas9 system targeting neuroprotective genes in general, and SIRT1 in particular, can be a potential novel therapy for acute ischemic stroke.

Multiparametric influence of 3D-printed organo-mineral scaffolds on bone regeneration.

The development of synthetic bone substitutes that equal or exceed the efficacy of autologous graft remains challenging. In this study, a rat calvarial defect model was used as a reference to investigate the influence of composition and architecture of 3D-printed cement, with or without bioactives, on tissue regeneration. Printable cement pastes were formulated by combining hyaluronic acid and cement precursors. Cementitious scaffolds were printed with 3 different patterns. After 7 weeks of implantation with or without bone marrow, multiparametric qualitative and quantitative assessments were performed using µCT, SEM, and histology. None of the set-up strategies was as efficient as autologous cancellous bone graft to repair calvarial defects. Nonetheless, the presence of scaffold improved the skull vault closure, particularly when the scaffold was soaked in total bone marrow before implantation. No significant effect of scaffold macro-architecture was observed on tissue mineralization. Magnesium phosphate-based scaffolds (MgP) seemed to induce higher bone formation than their calcium-phosphate-based counterparts. They also displayed a quicker biodegradation and sparse remaining material was found after 7 weeks of implantation. Although further improvements are required to reach clinical settings, this study demonstrated the potential of organo-mineral cements for bone regeneration and highlighted the peculiar properties of MgP-based cements.

Morphological study of remineralization of the eroded enamel lesions by tyrosine-rich amelogenin peptide.

BACKGROUND: Tyrosine-rich amelogenin peptide (TRAP) is the main amelogenin digestion product in the developmental enamel matrix. It has been shown to promote remineralization of demineralized enamel in our previous study. However, direct evidence of the effect of TRAP on the morphology and nanostructure of crystal growth on an enamel surface has not been reported. This study aimed to examine the effect of TRAP on the morphology of calcium phosphate crystals grown on early enamel erosion using a pH-cycling model. METHODS: Eroded lesions were produced in human premolars by 30-second immersion in 37% phosphoric acid. Forty-five samples of eroded human premolar enamel blocks were selected and randomly divided into 3 groups: deionized water (DDW, negative control); 100 µg/mL TRAP, and 2 ppm sodium fluoride (NaF, positive control group). For 14 days, the specimens were exposed to a pH-cycling model. Using scanning electron microscopy (SEM) and atomic force microscopy (AFM) methods, the surface morphology, calcium-phosphorus ratio, and enamel surface roughness were examined. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to assess crystal characteristics. RESULTS: After pH-cycling, compared to the two control groups, the surface of the eroded enamel of the peptide TRAP group shows a large number of new, densely arranged rod-like crystals, parallel to each other, regularly arranged, forming an ordered structure, with crystal morphology similar to that of natural enamel. The crystals are mostly hydroxyapatite (HA). CONCLUSION: This study demonstrates that the peptide TRAP modulates the formation of hydroxyapatite in eroded enamel and that the newly formed crystals resemble natural enamel crystals and promote the remineralization of enamel, providing a promising biomaterial for remineralization treatment of enamel lesions.

The Push-Out Bond Strength, Surface Roughness, and Antimicrobial Properties of Endodontic Bioceramic Sealers Supplemented with Silver Nanoparticles.

This study evaluated push-out bond test (POBT), surface roughness, and antimicrobial properties against Enterococcus faecalis of bioceramic sealers supplemented with silver nanoparticles (AgNPs). The sealers tested were CeraSeal®, EndoSequence® BC SealerTM, and Bio-C® Sealer. The POBT was measured with a Universal Testing Machine, and the type of failure was evaluated with a stereomicroscope. The roughness average (Sa) and peak-valley height (Sy) values were evaluated by atomic force microscopy. The bacterial growth inhibition was evaluated using a disk diffusion test, and antimicrobial activity was determined with the plate microdilution method. The POBT showed no significant difference between sealers with and those without NPs in cervical and apical thirds (p > 0.05). In the middle third, the adhesion force was significant for Endosequence BC Sealer® (p < 0.05). The results showed that the Sa and Sy parameters, when AgNPs were added, did not show a statistically significant difference compared to the groups without nanoparticles (p > 0.05). All tested sealers showed bacterial growth inhibition, but no significant difference was found. Their efficacy, in descending order of antibacterial activity when AgNPs were added, is as follows: EndoSequence® BC SealerTM > Bio-C® Sealer > CeraSeal®. The incorporation of AgNPs into bioceramics improves antimicrobial activity without affecting mechanical properties.

Biocompatibility and pro-mineralization effects of premixed calcium silicate-based materials on human dental pulp stem cells: An in vitro and in vivo study.

Premixed calcium silicate-based materials have recently been developed and are recommended for a wide range of endodontic procedures, including vital pulp therapy. This study investigated the in vitro biocompatibility and pro-mineralization effect and in vivo reparative dentin formation of EndoSequence Root Repair Material, EndoSequence BCRRM, Bio-C Repair, and Well-pulp PT. Both fresh and set extracts had no detrimental effect on the growth of human dental pulp stem cells. The fresh extracts had a higher calcium concentration than the set extracts and induced considerably greater mineralized nodule formation. EndoSequence Root Repair Material had the longest setting time, whereas Bio-C Repair had the shortest. When these materials were applied to exposed rat molar pulps, mineralized tissue deposition was found at the exposure sites after 2 weeks. These results indicate that the premixed calcium silicate-based materials tested could have positive benefits for direct pulp capping procedures.

Do Stainless-Steel Pins Coated with Fibroblast Growth Factor-Calcium Phosphatase Composite Layers Have Anti-Infective Effects?

Background: The most problematic complication of external fixation is infection at the pin insertion site. Technology that improves the adhesion of the external fixation pin to the skin, subcutaneous tissue, and bone may prevent infection at the pin site. The purpose of this study is to formulate a calcium phosphate-fibroblast growth factor (Cp-FGF) coating on a stainless-steel external fixation pin and to verify its effectiveness in reducing infection at the pin site and its possible influence on bone fixation in animal experiments. Methods: We compared stainless-steel screws without coating (SS group; n = 32), those with a calcium phosphate coating (Cp group; n = 30), those with a Cp-FGF coating (FGF group; n = 32), and those with a Cp-FGF coating having enhanced biological activity (FGF+ group; n = 32) in male Japanese white domesticated rabbits. Screws were inserted percutaneously into the bilateral proximal tibial diaphysis of the rabbits and implanted for 4 weeks. Screws and periscrew tissue were observed postoperatively for qualitatively assessing infection. Results: Infection assessment by gross findings after 4 weeks (at screw removal) showed no significant differences between the groups. Histopathological evaluation of soft tissue infection and bone tissue infection showed no significant differences between the groups for either soft tissue or bone tissue. Since neither the FGF+ group nor the FGF group showed anti-infective effects, the biological activity of FGF is not the only determining factor. We compared SEM, XRD, coating detaching test, sustained release test, and bioassay to examine physicochemical properties among the coatings but found no sufficient differences. Conclusions: It is suggested that improving the tissue adhesion to and/or biocompatibility of pins is also important to improve the in vivo performance of Cp-FGF-coated external fixation pins.

Effect of the Addition of Inorganic Fillers on the Properties of Degradable Polymeric Blends for Bone Tissue Engineering.

Bone tissue exhibits self-healing properties; however, not all defects can be repaired without surgical intervention. Bone tissue engineering offers artificial scaffolds, which can act as a temporary matrix for bone regeneration. The aim of this study was to manufacture scaffolds made of poly(lactic acid), poly(ε-caprolactone), poly(propylene fumarate), and poly(ethylene glycol) modified with bioglass, beta tricalcium phosphate (TCP), and/or wollastonite (W) particles. The scaffolds were fabricated using a gel-casting method and observed with optical and scanning electron microscopes. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR), differential scanning calorimetry (DSC), thermogravimetry (TG), wettability, and degradation tests were conducted. The highest content of TCP without W in the composition caused the highest hydrophilicity (water contact angle of 61.9 ± 6.3°), the fastest degradation rate (7% mass loss within 28 days), moderate ability to precipitate CaP after incubation in PBS, and no cytotoxicity for L929 cells. The highest content of W without TCP caused the highest hydrophobicity (water contact angle of 83.4 ± 1.7°), the lowest thermal stability, slower degradation (3% mass loss within 28 days), and did not evoke CaP precipitation. Moreover, some signs of cytotoxicity on day 1 were observed. The samples with both TCP and W showed moderate properties and the best cytocompatibility on day 4. Interestingly, they were covered with typical cauliflower-like hydroxyapatite deposits after incubation in phosphate-buffered saline (PBS), which might be a sign of their excellent bioactivity.

Calcium Citrate Amount and Gelatine Source Impact on Hydroxyapatite Formation in Bone Regeneration Material in Simulated Body Fluid.

Bone grafting is crucial for bone regeneration. Recent studies have proposed the use of calcium citrate (CC) as a potential graft material. Notably, citrate does not inhibit hydroxyapatite (HAp) formation at specific calcium-to-citrate molar ratios. Octacalcium phosphate (OCP)/gelatine (Gel) composites, which are commonly produced from porcine Gel, are valued for their biodegradability and bone replacement capability. This study introduces fish Gel as an alternative to porcine Gel because of its wide acceptance and eco-friendliness. This is the first study to examine the interaction effects between two osteogenic materials, OCP/CC, and the influence of different gelatine matrix components on HAp formation in an SBF. Samples with varying CC contents were immersed in an SBF for 7 d and analysed using various techniques, confirming that high CC doses prevent HAp formation, whereas lower doses facilitate it. Notably, small-sized OCP/CC/porcine Gel composites exhibit a high HAp generation rate. Porcine Gel composites form denser HAp clusters, whereas fish Gel composites form larger spherical HAps. This suggests that lower CC doses not only avoid inhibiting HAp formation but also enhance it with the OCP/Gel composite. Compared with porcine Gel, fish Gel composites show less nucleation but an increased crystal growth for HAp.

Adding calcium phosphate agents alongside fluorides may enhance caries prevention and remineralization, although evidence is limited.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Effectiveness of Calcium Phosphate derivative agents on the prevention and remineralization of caries among children- A systematic review & meta-analysis of randomized controlled trials. Singal K, Sharda S, Gupta A, Malik VS, Singh M, Chauhan A, Agarwal A, Pradhan P, Singh M. J Evid Based Dent Pract. 2022; 22(3):101746. SOURCE OF FUNDING: Indian Council of Medical Research. TYPE OF STUDY/DESIGN: Systematic review with meta-analysis.

Species-level characterization of gut microbiota and their metabolic role in kidney stone formation using full-length 16S rRNA sequencing.

The critical role of the human gut microbiota in kidney stone formation remains largely unknown, due to the low taxonomic resolution of previous sequencing technologies. Therefore, this study aimed to explore the gut microbiota using high-throughput sequencing to provide valuable insights and identify potential bacterial species and metabolite roles involved in kidney stone formation. The overall gut bacterial community and its potential functions in healthy participants and patients were examined using PacBio sequencing targeting the full-length 16S rRNA gene, coupled with stone and statistical analyses. Most kidney stones comprised calcium oxalate and calcium phosphate (75%), pure calcium oxalate (20%), and calcium phosphate and magnesium phosphate (5%), with higher content of Ca (130,510.5 ± 108,362.7 ppm) followed by P (18,746.4 ± 23,341.2 ppm). The microbial community structure was found to be weaker in patients' kidney stone samples, followed by patients' stool samples, than in healthy participants' stool samples. The most abundant bacterial species in kidney stone samples was uncultured Morganella, whereas that in patient and healthy participant stool samples was Bacteroides vulgatus. Similarly, Akkermansia muciniphila was significantly enriched in patient stool samples at the species level, whereas Bacteroides plebeius was significantly enriched in kidney stone samples than that in healthy participant stool samples. Three microbial metabolic pathways, TCA cycle, fatty acid oxidation, and urea cycle, were significantly enriched in kidney stone patients compared to healthy participants. Inferring bacteria at the species level revealed key players in kidney stone formation, enhancing the clinical relevance of gut microbiota.

Incorporation of calcium phosphate cement into decellularized extracellular matrix enhances its bone regenerative properties.

Decellularized extracellular matrix (dECM) hydrogels are engineered constructs that are widely-used in the field of regenerative medicine. However, the development of ECM-based hydrogels for bone tissue engineering requires enhancement in its osteogenic properties. For this purpose, we initially employed bone-derived dECM hydrogel (dECM-Hy) in combination with calcium phosphate cement (CPC) paste to improve the biological and structural properties of the dECM hydrogel. A decellularization protocol for bovine bone was developed to prepare dECM-Hy, and the mechanically-tuned dECM/CPC-Hy was built based on both rheological and mechanical characteristics. The dECM/CPC-Hy displayed a double swelling ratio and compressive strength. An interconnected structure with distinct hydroxyapatite crystals was evident in dECM/CPC-Hy. The expression levels of Alp, Runx2 and Ocn genes were upregulated in dECM/CPC-Hy compared to the dECM-Hy. A 14-day follow-up of the rats receiving subcutaneous implanted dECM-Hy, dECM/CPC-Hy and mesenchymal stem cells (MSCs)-embedded (dECM/CPC/MSCs-Hy) showed no toxicity, inflammatory factor expression or pathological changes. Radiography and computed tomography (CT) of the calvarial defects revealed new bone formation and elevated number of osteoblasts-osteocytes and osteons in dECM/CPC-Hy and dECM/CPC/MSCs-Hy compared to the control groups. These findings indicate that the dECM/CPC-Hy has substantial potential for bone tissue engineering.

Acidity-Actuated Polymer/Calcium Phosphate Hybrid Nanomotor (PCaPmotor) for Penetrating Drug Delivery and Synergistic Anticancer Immunotherapy.

Tumor acidity-driven nanomotors may offer robust propulsion for tumor-specific penetrating drug delivery. Herein, an acidity-actuated poly(amino acid) calcium phosphate (CaP) hybrid nanomotor (PCaPmotor) was designed, using a mPEG-PAsp-PPhe@THZ531 micelle (Poly@THZ) for CaP mineralization accompanied by αPD-L1 antibody encapsulation. Dissolution of the CaP layer in an acidic tumor environment gave off heat energy to propel the nanomotor to augment the cellular uptake and penetration into deeply seated cancer cells while facilitating αPD-L1 release. THZ531 delivered by the PCaPmotor inhibited CDK12 and its down-streamed phosphorylation of RNAP-II to increase the cancer immunogenicity events such as the DNA damage, cell apoptosis, immunogenic cell death, lysosomal function disturbance, and MHC-I upregulation. THZ531 and αPD-L1 cosupplied by PCaPmotor significantly increased the frequency of DCs maturation and intratumoral infiltration of CTLs, but the two free drugs did not. Consequently, the PCaP@THZ/αPD-L1 nanomotor resulted in synergistic anticancer immunotherapy in mice. This acid-actuated PCaPmotor represented a new paradigm for penetrating drug delivery.