Nanometabolomics Elucidated Biological Prospective of Mo4/3B2-x Nanosheets: Toward Metabolic Reprogramming of Amino Acid Metabolism.

Mo4/3B2-x nanosheets are newly developed, and 2D transition metal borides (MBene) were reported in 2021, but there is no report on their further applications and modification; hence, this article sheds light on the significance of potential biological prospects for future biomedical applications. Therefore, elucidation of the biocompatibility, biotoxicology, and bioactivity of Mo4/3B2-x nanosheets has been an urgent need to be fulfilled. Nanometabolomics (also referred as nanomaterials-based metabolomics) was first proposed and utilized in our previous work, which specialized in interpreting nanomaterials-induced metabolic reprogramming through aqueous metabolomics and lipidomics approach. Hence, nanometabolomics could be considered as a novel concept combining nanoscience and metabolomics to provide bioinformation on nanomaterials' biomedical applications. In this work, the safe range of concentration (<50 mg/L) with good biosafety toward human umbilical vein endothelial cells (HUVECs) was discovered. The low concentration (5 mg/L) and high concentration (50 mg/L) of Mo4/3B2-x nanosheets were utilized for the in vitro Mo4/3B2-x-cell interaction. Nanometabolomics has elucidated the biological prospective of Mo4/3B2-x nanosheets via monitoring its biocompatibility and metabolic shift of HUVECs. The results revealed that 50 mg/L Mo4/3B2-x nanosheets could lead to a stronger alteration of amino acid metabolism with disturbance of the corresponding amino acid-related pathways (including amino acid metabolism, amino acid degradation, fatty acid biosynthesis, and lipid biosynthesis and metabolism). These interesting results were closely involved with the oxidative stress and production of excess ROS. This work could be regarded as a pathbreaking study on Mo4/3B2-x nanosheets at a biological level, which also designates their further biochemical, medical, and industrial application and development based on nanometabolomics bioinformation.

A composite scaffold fabricated with an acellular matrix and biodegradable polyurethane for the in vivo regeneration of pig bile duct defects.

Bile duct regeneration is urgently needed to restore the normal function of the damaged biliary system. In this study, an artificial bile duct (ABD) was fabricated for extrahepatic bile duct regeneration based on biodegradable polyurethane (BPU) and ureter acellular matrix (UAM) to endow it with favorable biocompatibility and eliminate bile leakage during in vivo bile duct regeneration. The mechanical properties, in vitro simulation of bile flow and cytocompatibility of BPU-UAM ABD were evaluated in vitro, and surgical implantation in the biliary defect site in minipigs was implemented to reveal the in vivo degradation of BPU-UAM and regeneration of the new bile duct. The results indicated that BPU-UAM ABD with a mechanical strength of 11.9 MPa has excellent cytocompatibility to support 3T3 fibroblast survival and proliferation in extraction medium and on the scaffolds. The in vivo implantation of BPU-UAM ABD revealed the change of collagen content throughout the new bile duct regeneration. Biliary epithelial cells were observed at day 70, and continuous biliary epithelial layer formation was observed after 100 days of implantation. Altogether, the BPU-UAM ABD fabricated in this study possesses excellent properties for application study in the regeneration of bile duct. STATEMENT OF SIGNIFICANCE: Extrahepatic bile duct defects carry considerable morbidity and mortality because they are the only pathway for bile to go down into the intestinal tract. At present, no artificial bile duct can promote biliary regeneration. In this study, BPU-UAM ABD was built based on biodegradable polyurethane and ureter acellular matrix to form a continuous compact layer of polyurethane in the internal wall of UAM and avoid bile leakage and experimental failure during in vivo implantation. Our work verified the effectiveness of the synthesized biodegradable polyurethane emulsion-modified urethral acellular matrix in bile regeneration and continuous biliary epithelial layer formation. This study provided a new approach for the curing of bile duct defects and inducing new bile tissue formation.

Exploring the Biological Effect of Biosynthesized Au-Pd Core-Shell Nanoparticles through an Untargeted Metabolomics Approach.

The biosynthesis of Au-Pd core-shell nanoparticles (NPs) with wild-type Escherichia coli (Au-Pd/E. coli) is an excellent newly established, environmentally friendly synthetic method for the fabrication of nanomaterials compared to traditional chemosynthesis. However, there is insufficient detailed bioinformation on the compatibility, metabolic process, and mechanism of this approach. Metabolomics approaches have provided an excellent alternative to numerous bioinformatics approaches for shedding light on the biological response of an organism exposed to external stimuli at the molecular level. In this study, two different doses (8 and 80 µg/mL) of Au-Pd/E. coli were applied to treat human umbilical vein endothelial cells (HUVECs). Gas chromatography/mass spectrometry coupled with bioinformatics was used to analyze the changes in the HUVEC metabolome after treatment. The results indicated the occurrence of nonsignificant acute cytotoxicity based on cell proliferation and apoptosis analysis, while high concentrations (80 µg/mL) of Au-Pd/E. coli induced dramatic changes in energy metabolism, revealing a notable inhibition of the tricarboxylic acid (TCA) cycle along with the enhancement of glycolysis, the pentose phosphate pathway, fatty acid biosynthesis, and lipid accumulation, which was correlated with mitochondrial dysfunction. The metabolomics results obtained for this novel Au-Pd/E. coli-cell system could broaden our knowledge of the biological effect of Au-Pd/E. coli and possibly reveal material modifications and technological innovations.

[In vitro study of strontium-calcium sulfate compounds as bioactive bone grafted substitute].

This study was aimed to create strontium-calcium sulfate compounds for making a new bioactive material with osteoconductive and osteoinduceable activity for bone repairing. Its mechanics and degradation features were assessed in vitro. Powders of alpha-calcium sulfate hemihydrate (alpha-CSH) and SrCl2 were mixed completely to make Sr-calcium sulfate compounds materials with 6 different concentrations (0%, 0.1%, 0.3%, 0.5%, 1% and 2%) of Sr. Scanning electron microscope was used to observe the configuration of the new materials. The compressive strength of each material was tested. The materials were soaked into simulated body fluid (SBF) to test the features of degradation, which included pH, weight loss, declination of compressive strength and the changes of strontium ion concentration. The crystal appearances were influenced by incorporating of strontium. The compressive strength of non-strontium incorporating calcium sulfate was 36.65 +/- 2.22 MPa. When the concentration of strontium was increasing, the compressive strength measurements of the materials tended to decline. The compressive strength declined to 20.56 +/- 2.64 MPa when the strontium concentration reached to 2%. The pH value of the SBF declined when the time of degradation increased, but both of them were very stable. All of the materials got weight loss after being soaked in SBF for several weeks. The weight loss was slight within 4 weeks and it became dramatic after 4 weeks. When the concentration of strontium was increasing, the weight loss became more rapid and significant (P<0.05). During 0-4 weeks' degradation in SBF, the materials' compressive strength decreased much slower when the strontium concentration was below 0.5%; however, when the decrement of strength became faster, the strontium concentration became higher. The concentration of strontium ion in SBF began to increase faster after 4 weeks' soaking in SBF. As the concentration of strontium was increasing, the strontium ion concentration in SBF became higher (P = 0.000). The new compound materials made by the mixing of alpha-calcium sulfate hemihydrate and SrCl2 can provide efficient compressive strength. The features of degradation of the materials are very stable. The new materials can release lots of bone inducible substance-strontium ions to repair bone defection after 4 weeks of degradation.

[Reconstruction of acetabular defect with wire mesh and impacted bone graft in cemented acetabular revision].

OBJECTIVE: To discuss the method of reconstruction of acetabular bone defect with wire mesh, impaction bone-grafting and a cemented cup in acetabular component revision. METHODS: 21 hips in 21 patients, aged 50.1 (31 - 64), 2 hips being of the acetabular defect type I B, 1 hip of type II A, 4 hips of type II B, and 14 hips of type III according to the American Academy of Orthopaedic Surgeons (AAOS) grading system underwent reconstruction with wire mesh, impacted bone grafts and cemented polyethylene acetabular component, and then were followed up for 47 months (36 - 60 months). RESULTS: The mean Harris hip score improved from the preoperative 55.7 points to 92.9 points at the last time of follow-up. Radiographic incorporation between host the bone and allograft was achieved 11.4 months after the operation on average. The mean change of inclination of acetabular components was 2.2 degrees , in which one acetabular component developed a change of 15.5 degrees . The inclination of acetabular components increased by 1.7 degrees on average 3 months after the operation and 2.0 degrees 6 months after the surgery. The acetabular cup migrated medially and superiorly by 3.93 mm and 4.41 mm respectively, peaking in the sixth month after the operation. One hip developed heterotopic ossification (Brooker grade I). One hip received repeat revision because of the aseptic loosening of the acetabular component 25 months after the revision surgery. CONCLUSION: The changes of the position of acetabular cup mainly occur within six months after the reconstruction of severe acetabular bone defect with wire mesh, impacted bone graft and cemented polyethylene acetabular component. To prevent the displacement of the acetabular cup, it is necessary to keep initial stability of the acetabular cups within six months after the index surgery.

[FABRICATION AND BIOCOMPATIBILITY EVALUATION OF POLYURETHANE- ACELLULAR MATRIX COMPOSITE SCAFFOLD IN VITRO AND IN VIVO].

OBJECTIVE: To prepare a composite scattold using bladder acellular matrix (BACM) and polyurethane (PU) for bladder repair and regeneration, and to evaluate its mechanical properties and biocompatibility. METHODS: Fresh bladder tissues were obtained from New Zealand rabbits and then treated with 1%SDS and 1%Triton X-100 to obtain BACM. The BACM was combined with PU to fabricate PU-BACM composite scaffold. The tensile strength and elongation at break of BACM and PU-BACM scaffolds were tested. Scaffolds and extracts of scaffolds were prepared to evaluate the biocompatibility. For cell-proliferation analysis, cell counting kit 8 method was used at 1, 3, 5, and 7 days after co-culture of human. bladder smooth muscle cell (HBSMC) and scaffolds. The cell cycle was tested by flow cytometry after HBSMC co-cultured with extracts of scaffolds and DMEM culture medium (control group) for 24 hours. Finally, 12 New Zealand rabbits were used to establish the model of bladder repair and regeneration. Incision of 5 mm was made on the bladder, and PU-BACM scaffold was sutured with the incision. The rabbits were sacrificed at 10, 20, 40, and 60 days after surgery to observe the inflammatory cell infiltration, new tissues formation, and regeneration of epithelium by HE staining. RESULTS: The tensile strength of BACM and PU-BACM composite scaffold was (5.78 ± 0.85) N and (11.88 ± 3.21) N, and elongation at break was 14.46% ± 3.21% and 23.14% ± 1.32% respectively, all showing significant diffeence (t = 3.182, P = 0.034; t = 4.332, P = 0.012). The cell-proliferation rates of controls, PU, BACM, and PU-BACM were 36.78% ± 1.21%, 30.49% ± 0.89%, 18.92% ± 0.84%, and 22.42% ± 1.55%, it was significantly higher in PU-BACM than BACM (P < 0.05). In the bladder repair and regeneration experiment, inflammatory cell infiltration was observed at 10 days after operation, and reduced at 20 days after implantation. In the meanwhile, the degradation of scaffolds was observed in vivo. The regeneration of epithelium could be observed after 40 days of implantation. At 60 days after implantation, in situ bladder tissue formed. CONCLUSION: PU-BACM composite scaffold has higher mechanical properties and better biocompatibility than BACM scaffold. PU-BACM composite scaffold will not lead to strong immune response, and new bladder tissue can form in the in vivo rabbit bladder repair experiment. These results can provide research basis and theoretical data for further study.

[Advances and prospective application of stem cell technique in stomatology].

In this paper the background and advances of stem cell technique in stomatology were reviewed, especially the lately research of repair of maxillofacial defects with bone marrow stem cells, repair or reconstitution of teeth with dental pulp stem cells and repair of other tissues such as parotid with embryonic stem cell. Stem cell technique provides a new choice and extensive prospect of application for stomatology, therefore, deserves further research.

[Application of enzyme histochemistry in evaluation of in vitro and in vivo biocompatibility of HA/TCP].

In order to explore the possibility of applying enzyme histochemistry in biocompatibility evaluation, we investigated the effect of biomaterials on the activities of intracellular enzymes in this experiment. It was found that there was no obvious difference in morphology between osteoblasts co-cultured with HA/TCP and with Ti-alloy. However, transient down-regulation of NADH, SDH, LDH and CCO of the osteoblasts co-cultured with HA/TCP was detected by enzyme histochemistry, but these enzymes of osteoblasts the co-cultured with Ti-alloy were not down-regulated. It was indicated that something extracted from HA/TCP injured the co-cultured osteoblasts slightly. Similar early acute inflammatory reactions were observed after HA/TCP and Ti-alloy were separately implanted into the dorsal muscle of rabbit. There was also no obvious difference between the tissue response to HA/TCP and that to Ti-alloy. Activities of enzymes in tissues around implanted materials were down-regulated at the early injury period and recovered gradually within 30 days post-operation. But the mild toxicity of extracts from HA/TCP was demonstrated by the fact that the recovery period of HA/TCP group was longer than that of Ti-alloy group. It was proved that enzyme histochemistry is more sensitive than tissue morphology analysis in detecting the cell or tissue responses to biomaterials. Therefore, it is possible to use enzyme histochemistry in biocompatibility evaluation.

[Visualizing living fibroblast on co-cultured denture base resin by green fluorescent protein marker introduced into the cell].

Visualizing living cells growing on co-cultured biomaterials is ideal for material biocompatibility evaluation in vitro. In this experiment, mouse fibroblasts L929 were labeled by introducing the gene coding enhanced green fluorescent protein (EGFP) marker into the cells. Morphology as well as proliferation of labeled cells surrounding or on the surface of co-cultured denture base resin slides were observed by use of phase-contrast microscope and fluorescent microscope directly. It was found that residual methyl methacrylate (MMA) in the denture base resin exhibited transient cytotoxicity to fibroblasts and this transient cytotoxicity could be eliminated by pre-extracting the resin with ddH2O for a short time. This fact demonstrated that even slight cytotoxicity of materials could be detected through imaging of living cells near material or material touched. And it was suggested that imaging of living cells co-cultured with biomaterial is helpful to understanding biocompatibility of materials more accurately.

[Osteogenesis of HA/TCP biphasic ceramics implanted into muscle: a long-term study].

New bone formation in long-term intramuscle implant of Ca-P biomaterial was investigated in this experiment. After implanting into dog dorsal muscle for 15 months, a thin fibrous membrane that wrapped HA/TCP implant was still observed obviously. Three types of tissues, i.e. mesenchymal tissue, bone and bone marrow, regularly distributed in different pores of implant. Nearly all the pores of implants were occupied by bone. Bone in the pores located in the central region of implant was matured lamellar bone characterized by obvious lacuna and rich bone marrow. However, bone in the peripheral pores was immature woven bone without bone marrow formation. Furthermore, mesenchymal tissues only exist in the peripheral pores and usually were connected with immature woven bone. It was demonstrated that porous HA/TCP has bone inductivity and it could induce new bone formation at non-osseous site. Well-regulated distribution of mesenchymal tissue, bone and bone marrow in the pores suggest bone morphogenesis in the implant must obey a specific space-time program.

Effectiveness of chemical biliary duct embolization for chemical hepatectomy.

BACKGROUND AND AIMS: The high recurrence of hepatolithiasis and high operative trauma of hepatectomy necessitate new therapeutic approaches. Thus, this study was designed to (i) investigate the effectiveness of chemical biliary duct embolization (CBDE) for chemical hepatectomy; and (ii) to determine the mechanism of CBDE. METHODS: The median biliary ducts in rats were injected with phenol or absolute ethanol alone, or in conjunction with cyanoacrylate. The effectiveness of CBDE for chemical hepatectomy was assessed by investigating histology, in situ hybridization for Fas and transforming growth factor (TGF)-beta1, immunohistochemistry for alpha-smooth muscle actin, and reverse transcription-polymerase chain reaction (RT-PCR) for procollagen I mRNA. RESULTS: Histologically, phenol or absolute ethanol plus cyanoacrylate could embolize the targeted bile duct and promote hepatic fibrosis and atrophy in the embolized lobe better than using phenol or ethanol alone. In addition, CBDE accelerated hepatocellular apoptosis via up-regulation of Fas, thereby resulting in the death of hepatocytes, which were replaced by proliferative bile ductules and collagen. Importantly, the hepatocytes disappeared completely in the periphery of the embolized lobe, thus achieving the desired effects of chemical hepatectomy. Further investigation indicated that CBDE initiated progressive fibrogenic processes of chemical hepatectomy via up-regulation of TGF-beta1, which greatly enhanced the synthesis of collagen. Indeed, higher levels of TGF-beta1 and procollagen I mRNA were observed in the phenol embolization group than in any other group. CONCLUSION: Chemical biliary duct embolization, especially using phenol plus cyanoacrylate, might achieve the effects of chemical hepatectomy.

The practical value of applying chemical biliary duct embolization to chemical hepatectomy for treatment of hepatolithiasis.

BACKGROUND: The high recurrence rate of hepatolithiasis, together with the high operative risk of hepatectomy for specifically located stones, has not been effectively settled until now. Thus, the aim of this study was to investigate the feasibility and effectiveness of using chemical biliary duct embolization (CBDE) to achieve chemical hepatectomy in a rabbit model of hepatolithiasis. MATERIALS AND METHODS: The animal model of hepatolithiasis was established using the methods of obstruction plus infection. Seven days later, the left hepatic ducts were embolized using phenol plus cyanoacrylate or absolute ethanol plus cyanoacrylate. Subsequently, the influence of CBDE on bile duct, liver, and stone formation was analyzed by histology, RT-PCR for procollagen, biochemistry, and enzymatic histochemistry for beta-glucuronidase (beta-G). RESULTS: CBDE resulted in the entire ablation of the diseased biliary duct mucosa and the complete occlusion of the diseased biliary duct lumen, thus effectively eradicating chronic proliferative cholangitis and preventing stone formation. More importantly, CBDE also resulted in the complete fibrosis and "self-cut" in the periphery of the embolized lobe, thus achieving chemical hepatectomy. Also of note, the embolized lobe exhibited a much lower level of endogenous beta-G than the nonembolized lobe, indicating an inhibitory effect of CBDE on beta-G. Besides, the mRNA level of procollagen I in the embolized bile duct wall of phenol embolization group was significantly higher than the ethanol embolization group. CONCLUSION: Chemical biliary duct embolization, especially using phenol plus cyanoacrylate, may prevent the recurrence of intrahepatic stone and concurrently achieve the effect of chemical hepatectomy.

[Influence of dosage on cell biocompatibility of hydroxyapatite/tricalcium phosphate].

OBJECTIVE: To investigate the influence of different dose levels of hydroxyapatite/tricalcium phosphate (HA/TCP) on the proliferation and alkaline phosphatase (ALP) activity of rabbit osteoblasts. METHODS: Three different dose levels of HA/TCP (10%, 40%, 70%) were co-cultivated with rabbit osteoblasts respectively. The proliferation and ALP expression capacity of osteoblasts were examined with MTT method and enzyme histochemistry once every 24 hours until 5 days. Three control groups of other materials were treated and examined in the same way: rabbit osteoblasts as normal control; polyvinylchloride as positive control; titanium alloy as negative control. RESULTS: There was remarkable time-effect relationship in the proliferation of osteoblasts. Ten percent HA/TCP did not affect osteoblasts growth while 40% HA/TCP could slow the cell growth rate down though time-effect relationship still existed. The proliferation of osteoblasts stagnated when co-cultivated with 70% HA/TCP. On the other hand, 10% HA/TCP could cause reversible damage on ALP activity of osteoblasts, whereas when the dose was 40%, and the cultivation lasted 6 days the damage was irreversible. Three different dose levels of titanium alloy (10%, 40%, 70%) had no effect on the proliferation or ALP activity of osteoblasts. CONCLUSION: Dosage is an important factor affecting the biocompatibility evaluation of biomaterial. It suggests that dose choosing should be more specified upon each individual biomaterial. It also indicates that ALP may be a good supplementary index of the cell compatibility of material.