Tissue engineering. Part C, Methods最新文献

Glioblastoma (GBM) is a highly aggressive and recurrent brain cancer characterized by diffuse metastasis at the tumor margins. Radiation therapy is a standard component of current treatment and offers potential for improved patient outcomes. While radiation therapy targets GBM cells in the tumor margins, it may also significantly damage adjacent noncancerous tissues, leading to reduced quality of life and potentially creating a tumor-supportive microenvironment. The perivascular niche (PVN) in the tumor margins is believed to play a significant role in regulating the glioblastoma stem cell subpopulation as well as serving as a site for cancer recurrence and migration. Understanding the impact of radiation on the PVN can better inform radiation schemes and improve our understanding of GBM recurrence, but is difficult in vivo. Here, we adapt a previously developed three-dimensional hydrogel model of the brain PVN to investigate the impact of radiation dosage and delivery rate on PVN properties in vitro. Effects of radiation on vessel architecture can be measured in this hydrogel-based model, suggesting an approach that can provide insight into the effects of radiation on a shorter time scale relative to in vivo experiments.

Based on various research, different cells are effective for improving the symptoms and paraclinical indicators of patients with chronic spinal cord injury (SCI). A big gap in front of researchers and doctors is to know the source, the number of cells required for injection, the delivery method, and the required complementary treatments. We extracted the desired data (number of cells, autologous or allogeneic source of cell extraction, delivery method, and complementary treatments) from 40 clinical trials, which checked and recorded 17 scores of symptoms and paraclinical indicators in at least two studies. The most common cells for improving 11 scores were bone marrow hematopoietic stem cell and bone marrow mesenchymal stem cell. The mean effect was more in bone marrow mesenchymal stem cell with plasma as the complementary treatment. Then the highest mean effect was in bone marrow hematopoietic stem cell therapy, with the complementary treatment being methylprednisolone. The cell number (10⁶/kg), the source (autologous), and the delivery method (intrathecal) were similar in both cell types. No life-threatening consequences or death were recorded. This guideline helps researchers and doctors choose the appropriate cell therapy method for chronic SCI.

Decellularization does not completely remove the matrix-bound α-Gal epitopes in porcine acellular dermal matrix (pADM), and the presence of residual α-Gal epitopes could elicit adverse immunological reactions and cause potential early failure of xenografts. The present study had evaluated the effectiveness of decellularization and α-galactosidase treatment to eliminate the matrix-bound α-Gal epitopes in pADM, as well as the effect of tissue form (intact pADM vs. microparticle). Decellularization eliminated ∼80% of α-Gal epitopes in porcine dermis, and pADM retained ∼20% of the matrix-bound α-Gal epitopes. While Aspergillus α-galactosidase and Coffea α-galactosidase both hydrolyzed the terminal alpha-galactosyl moiety from oligosaccharides, only Coffea α-galactosidase was effective in eliminating the matrix-bound α-Gal epitopes in intact pADM. Aspergillus α-galactosidase did not work for intact pADM, even at an enzyme activity more than an order of magnitude higher than that of Coffea α-galactosidase used. The different efficacy between Aspergillus α-galactosidase and Coffea α-galactosidase was associated to the accessibility to the matrix-bound α-Gal epitopes in intact pADM. When intact pADM was micronized into fine microparticles, Aspergillus α-galactosidase and Coffea α-galactosidase eliminated the matrix-bound α-Gal epitopes equally well. Thus, the tissue form had significant influence on the efficacy of enzymic cleavage. The findings of the study offer valuable insight for enzyme selection and process development for efficient α-Gal antigen reduction in xenogeneic grafts or tissue scaffolds.

Cell membrane isolation is essential for diverse biological investigations, ranging from fundamental research to advanced therapeutic applications. This study compared two methods-differential centrifugation and discontinuous sucrose density gradient ultracentrifugation-for isolating cell membranes from the human natural killer (NK) cell line (KHYG-1). The aim was to identify the method that minimizes contamination from nuclear, mitochondrial, and cytosolic components. Differential centrifugation yielded approximately 8 mg of cell membrane, whereas sucrose density gradient ultracentrifugation produced about 5 mg. Despite the lower yield, the latter method exhibited superior performance due to significantly reduced contamination. This protocol is adaptable to various cell types, offering a reliable approach for producing cell membrane-coated mimics for therapeutic use. The increasing demand for isolated cell membranes in biomedical applications highlights the importance of optimizing isolation techniques.

Experimental analyses of knee joint contractures have traditionally utilized a 6-month rabbit model as the gold standard. However, this model is time-intensive and costly. The purpose of this study was to develop an abbreviated rabbit model of knee contractures and compare it to the well-established longer model. Twenty female New Zealand White rabbits were divided into two equal groups and prospectively studied to assess knee passive extension angles (PEA), contracture angles (CA), and terminal posterior capsular stiffness. Experimental knees were immobilized for either 4 weeks (n = 10) with an 8-week remobilization period in the abbreviated model (i.e., 3 months) or for 8 weeks (n = 10) with a 16-week remobilization period in the standard model (i.e., 6 months). PEAs were assessed at remobilization and several time points using differing vertical forces. At sacrifice, terminal biomechanical data were collected to assess posterior capsular stiffness. Analysis of PEAs in live animals at each torque value and time point demonstrated increased PEAs and decreased CAs in the 3-month abbreviated model as compared to the 6-month standard model. At sacrifice, biomechanical analysis demonstrated that the posterior capsules of the 3-month experimental limbs were significantly more stiff than the contralateral limb (2.4 vs. 0.05 Ncm/°, p < 0.0001), but significantly less stiff compared to the 6-month experimental limbs (2.4 vs. 4.7 Ncm/°, p < 0.0001). Our study suggests that the 6-month standard rabbit knee model of arthrofibrosis should continue to be used in the laboratory assessment of arthrofibrosis. However, the abbreviated model may be beneficial under selected experimental conditions.

To investigate the histomorphometric performance of two-stage maxillary sinus floor elevation (TMSFE) with various bone substitutes in the treatment of atrophic posterior maxilla. Four databases (PubMed, Embase, Web of Science, and The Cochrane Library) were searched from the beginning of database establishment to August 8, 2023. The included articles were limited to the English language. A systematic search was performed to identify randomized controlled trials assessing the histological performance of various biomaterials in TMSFE with a follow-up of 5-8 months. The main outcome was an area of new bone, and an additional outcome was residual graft material. Extracted data were analyzed by using a Bayesian approach (the Markov chain Monte Carlo) to establish ranks of various biomaterials in R language. Finally, the search identified 22 studies that reported 22 trials on bone area (17 kinds of biomaterials) and 12 studies on residual graft materials (12 kinds of biomaterials) after the exclusion of one study disconnected from the network plot. No local inconsistency could be found in studies regarding bone formation, while no closed loop was detected in residual graft material. The top 3 probabilities of biomaterials in terms of bone formation were Allograft + Xenograft (AG + X) (87.14%), X + Polymer (75.69%), and Autogenous Bone + Bioactive Glass (AB + BG) (71.44%). AG + X had the highest probability (87.14%) of being the most optimal treatment for bone formation. Biphasic calcium phosphate + Fibrin sealant (BCP + FS) was ranked as the slowest absorbing biomaterial (78.27%) in TMSFE. Within the limitations of the current network meta-analysis, AG + X may represent an optimal biomaterial for bone formation in TMSFE. The use of X in combination with other biomaterials demonstrates superior osteogenic effects in TMSFE. BCP + FS exhibited strong mechanical properties during a short-term observational period. The present findings suggest that AB is not the only feasible standard for bone grafts.

Stem cells play a critical role in the regeneration process by proliferating and differentiating to form new bone tissue. However, stem cells tend to lose their stemness and pluripotency during in vitro expansion, resulting in reduced bone regeneration capacity after osteogenic induction. Our aim is to enhance the osteogenic impact of human umbilical cord-derived mesenchymal stromal cells (hUC-MSCs) through spontaneous spheroid in vitro. The pluripotency and osteogenesis-related genes up-regulated in hUC-MSCs can be enhanced in spontaneous spheroids in vitro. For in vivo testing, spontaneous spheroids were transplanted into mice using beta-tricalcium phosphate as a scaffold. Transplant samples were stained using hematoxylin and eosin (HE), immunohistochemistry, and TRAP staining. The samples showed new bone formation, upregulated SP7 and OCN expression, and more vigorous bone metabolism in the Sph-OI group than the other groups. However, new bone formation was mainly immature bone. Overall, our findings demonstrate that hUC-MSC spheroids possess remarkable pluripotency, with the spontaneous spheroids formed following osteogenic induction exhibiting enhanced osteogenic differentiation potential and bone regeneration capacity. However, optimizing the osteogenic differentiation process and elucidating the underlying mechanisms of bone regeneration are critical scientific issues that urgently need to be addressed to enable its application in bone regeneration.