Metal Ion-Containing Hydrogels: Synthesis, Properties, and Applications in Bone Tissue Engineering.

Hydrogel, as a unique scaffold material, features a three-dimensional network system that provides conducive conditions for the growth of cells and tissues in bone tissue engineering (BTE). In recent years, it has been discovered that metal ion-containing hybridized hydrogels, synthesized with metal particles as the foundation, exhibit excellent physicochemical properties, osteoinductivity, and osteogenic potential. They offer a wide range of research prospects in the field of BTE. This review provides an overview of the current state and recent advancements in research concerning metal ion-containing hydrogels in the field of BTE. Within materials science, it covers topics such as the binding mechanisms of metal ions within hydrogel networks, the types and fabrication methods of various metal ion-containing hydrogels, and the influence of metal ions on the properties of hydrogels. In the context of BTE, the review delves into the osteogenic mechanisms of various metal ions, the applications of metal ion-containing hydrogels in BTE, and relevant experimental studies in vitro and in vivo. Furthermore, future improvements in bone repair can be anticipated through advancements in bone bionics, exploring interactions between metal ions and the development of a wider range of metal ions and hydrogel types.

Spatially explicit estimation of freshwater fish stock biomass with limited data: A case study of an endangered endemic fish on the Tibetan Plateau, China.

Accurate evaluation of fish stock biomass is essential for effective conservation management and targeted species enhancement efforts. However, this remains challenging owing to limited data availability. Therefore, we present an integrated modeling framework combining catch per unit effort with ensemble species distribution modeling called CPUESDM, which explicitly assesses and validates the spatial distribution of stock biomass for freshwater fish species with limited data, applied to Herzensteinia microcephalus. The core algorithm incorporates the Leslie regression model, ensemble species distribution modeling, and exploratory spatial interpolation techniques. We found that H. microcephalus biomass in the Yangtze River source area yielded an initial estimate of 113.52 tons. Our validation results demonstrate high accuracy with a Cohen's kappa coefficient of 0.78 and root mean square error of 0.05. Furthermore, our spatially-explicit, global, absolute biomass density map effectively identified areas with high and low concentrations of biomass distribution centers. Additionally, this study offers access to the source code, example raw data, and a step-by-step instruction manual for other researchers using field data to explore the application of this model. Our findings can help inform for future conservation efforts around fish stock biomass estimation, especially for endangered species.

A New Biomaterial Derived from Aloe vera-Acemannan from Basic Studies to Clinical Application.

Aloe vera is a kind of herb rich in polysaccharides. Acemannan (AC) is considered to be a natural polysaccharide with good biodegradability and biocompatibility extracted from Aloe vera and has a wide range of applications in the biomedical field due to excellent immunomodulatory, antiviral, antitumor, and tissue regeneration effects. In recent years, clinical case reports on the application of AC as a novel biomedical material in tissue regenerative medicine have emerged; it is mainly used in bone tissue engineering, pulp-dentin complex regeneration engineering, and soft tissue repair, among other operations. In addition, multiple studies have proved that the new composite products formed by the combination of AC and other compounds have excellent biological and physical properties and have broader research prospects. This paper introduces the preparation process, surface structure, and application forms of AC; summarizes the influence of acetyl functional group content in AC on its functions; and provides a detailed review of the functional properties, laboratory studies, clinical cutting-edge applications, and combined applications of AC. Finally, the current application status of AC from basic research to clinical treatment is analyzed and its prospects are discussed.

Research progress of functional motifs based on growth factors in cartilage tissue engineering: A review.

Osteoarthritis is a chronic degenerative joint disease that exerts significant impacts on personal life quality, and cartilage tissue engineering is a practical treatment in clinical. Various growth factors are involved in cartilage regeneration and play important roles therein, which is the focus of current cartilage repair strategy. To compensate for the purification difficulty, high cost, poor metabolic stability, and circulating dilution of natural growth factors, the concept of functional motifs (also known as mimetic peptides) from original growth factor was introduced in recent studies. Here, we reviewed the selection mechanisms, biological functions, carrier scaffolds, and modification methods of growth factor-related functional motifs, and evaluated the repair performance in cartilage tissue engineering. Finally, the prospects of functional motifs in researches and clinical application were discussed.

Surface Modification of Multiple Bioactive Peptides to Improve Endothelialization of Vascular Grafts.

Endothelialization is an effective approach to prevent thrombus formation and enhance vascular graft survival. Surface modification of biomolecules has been proved to be effective in regulating endothelial cell behaviors. In this study, several peptides including YIGSR, RGD, and REDV sequences are covalently immobilized on the surface of electrospun silk fibroin scaffolds and the effects of combined application of these peptides on cell behaviors are studied. The results show that, compared with the scaffolds modified with single peptides, the scaffolds modified with dual peptides (YIGSR+RGD) could significantly enhance the proliferation of human umbilical vein endothelial cells (HUVECs). However, the combination of REDV+RGD or YIGSR+REDV does not promote the adhesion or proliferation of HUVECs. Notably, YIGSR-modified scaffolds improved HUVEC migration significantly in comparison to REDV- or RGD-modified groups. Moreover, its combination with either of these two peptides also presents excellent effect on cell migration. Thus, all the data suggest that the combined application of peptides might be a promising method to enhance the endothelialization of small-diameter vascular grafts.

Enhancing neural differentiation of induced pluripotent stem cells by conductive graphene/silk fibroin films.

Nerve regeneration and function recovery remain challenges for tissue engineering. The application of suitable scaffold in tissue engineering has been demonstrated to be able to enhance nerve regeneration and differentiation. However, a desired scaffold must meet the requirements of good cytocompatibility and high electrical conductivity simultaneously. In this study, a conductive film composed of SF and graphene was successfully fabricated, which was applied to evaluate its effect on the neural differentiation of iPSCs. The conductive film was found to enhance the differentiation of iPSCs toward neurons. In addition, the differentiation was enhanced with graphene contents and highest value was obtained at graphene content of 4%. Thus, the results in this study suggested that 4% G/SF film might be a suitable biomaterial scaffold for application in neural regeneration. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2973-2983, 2018.

Regulating Coupling Efficiency of REDV by Controlling Silk Fibroin Structure for Vascularization.

Controlled and rapid vascularization of engineered tissues remains one of the main challenges for tissue engineering. The immobilization of peptides and other bioactive molecules on the scaffolds has been demonstrated to be able to improve vascularization. However, the density of peptides modified on the scaffold surface is an important factor influencing vascularization. Thus, regulating the coupling efficiency of peptides may be an effective way to adjust vascularization. In this study, two-dimensional (2D) silk fibroin (SF) films and three-dimensional (3D) porous SF scaffolds with different secondary structure were prepared and coupled with Arg-Glu-Asp-Val (REDV) peptide. Compared with the high crystalline scaffolds, more peptides were bound on the scaffolds with low crystalline both in 2D and 3D forms with the result that more endothelial cells adhered on the low crystalline SF scaffolds. In addition, the in vivo angiogenic assays demonstrated that the low crystalline scaffolds showed higher blood vessel density after 28 days of implantation, which was 1.4-times as much as that of the high crystalline group. The results indicated that the peptide density could be controlled by SF structure and that the low crystalline SF scaffolds modified with REDV peptide could be a potential candidate for inducing angiogenesis in tissue engineering applications.

Retroperitoneal fibrosis: a clinical and outcome analysis of 58 cases and review of literature.

The purpose of the study was to investigate the clinical features and outcomes of retroperitoneal fibrosis (RPF). Fifty-eight RPF treatment cases in the First Affiliated Hospital of China Medical University were retrospectively analyzed, including clinical characteristics and laboratory data. RPF was found predominantly in elderly men with atypical clinical manifestations of back pain, abdominal pain, and lower limb edemas. In laboratory examinations, the acute-phase reactants such as erythrocyte sedimentation rate and C-reactive protein levels increased significantly. Renal function failure was frequently found in patients with urethral obstruction. All patients had retroperitoneal soft tissue shadows or urethral obstructions on computed tomography (CT) or magnetic resonance imaging (MRI), seven of which had histological diagnosis of idiopathic RPF. Forty-two patients received surgical interventions; 29 patients received medication treatment alone including corticosteroids, immunosuppressants, and tamoxifen; 17 patients received corticosteroids after surgical intervention. Surgery followed by medication was most effective for RPF. CT and MRI help to exclude secondary causes, but biopsy remains the gold standard for diagnosis. Long-term low-dose corticosteroids and immunosuppressants may prevent relapse of RPF.

Identification of novel genomic aberrations in AML-M5 in a level of array CGH.

To assess the possible existence of unbalanced chromosomal abnormalities and delineate the characterization of copy number alterations (CNAs) of acute myeloid leukemia-M5 (AML-M5), R-banding karyotype, oligonucelotide array CGH and FISH were performed in 24 patients with AML-M5. A total of 117 CNAs with size ranging from 0.004 to 146.263 Mb was recognized in 12 of 24 cases, involving all chromosomes other than chromosome 1, 4, X and Y. Cryptic CNAs with size less than 5 Mb accounted for 59.8% of all the CNAs. 12 recurrent chromosomal alterations were mapped. Seven out of them were described in the previous AML studies and five were new candidate AML-M5 associated CNAs, including gains of 3q26.2-qter and 13q31.3 as well as losses of 2q24.2, 8p12 and 14q32. Amplication of 3q26.2-qter was the sole large recurrent chromosomal anomaly and the pathogenic mechanism in AML-M5 was possibly different from the classical recurrent 3q21q26 abnormality in AML. As a tumor suppressor gene, FOXN3, was singled out from the small recurrent CNA of 14q32, however, it is proved that deletion of FOXN3 is a common marker of myeloid leukemia rather than a specific marker for AML-M5 subtype. Moreover, the concurrent amplication of MLL and deletion of CDKN2A were noted and it might be associated with AML-M5. The number of CNA did not show a significant association with clinico-biological parameters and CR number of the 22 patients received chemotherapy. This study provided the evidence that array CGH served as a complementary platform for routine cytogenetic analysis to identify those cryptic alterations in the patients with AML-M5. As a subtype of AML, AML-M5 carries both common recurrent CNAs and unique CNAs, which may harbor novel oncogenes or tumor suppressor genes. Clarifying the role of these genes will contribute to the understanding of leukemogenic network of AML-M5.

[Expression of death-associated protein kinase gene and methylation status of promoter region in acute leukemia].

This study was purpose to investigate the expression of death-associated protein kinase (DAPK) gene in acute leukemia (AL) patients and the methylation status of its promoter region through experiments of DAPK methylation and expression, and to analyze the relation between them. The expression of DAPK gene in leukemia cells and normal bone marrow cells was detected by RT-PCR; the methylation status of DAPK gene promoter region in cells from AL patients and leukemia cell lines HL-60 and U937 was detected by nested methylation specific PCR (n-MSP); 2 randomly primers selected from randomly amplified products of second round nMS-PCR were cloned and sequenced in professional company. The results showed that the DAPK gene expressed in bone marrow specimens of all 10 normal controls, with average value of expression 0.92 ± 0.18, while the average value of DAPK expression in bone marrow specimens of AL patients was 0.61 ± 0.40 which was lower than that in normal controls (P < 0.05). The low or deletion of DAPK mRNA expression were found in bone marrow specimens of 9/17 (52.94%) cases of ALL and 42/102 (41.18%) cases of AML. The cell line U937 showed normal expression of DAPK gene, while cell line HL-60 showed the expression detection of DAPK gene. The methylation of DAPK promoter region existed in 33 out of bone marrow specimens of 102 AML patients and in 8 out of bone marrow specimens of 17 ALL patients, the methylation rates were 32.4% (33/102) and 47% respectively. The DAPK promoter region in bone marrow of 7 normal controls was unmethylated, while DAPK promoter region in U937 cells and HL-60 cells were unmethylated and methylated respectively. The DAPK mRNA expression in ALL and AML patients significantly negatively correlated with the methylation of its promoter region (r = -0.855, P < 0.05, in AML patients and r = -0.343, P < 0.05, in AML patients) suggesting the close relationship between them. It is concluded that the methylation of DAPK gene promoter region relates with abnormal expression or detection of DAPK mRNA in AL patients.