Effect of viscosity of gelatin methacryloyl-based bioinks on bone cells.

The viscosity of gelatin methacryloyl (GelMA)-based bioinks generates shear stresses throughout the printing process that can affect cell integrity, reduce cell viability, cause morphological changes, and alter cell functionality. This study systematically investigated the impact of the viscosity of GelMA-gelatin bioinks on osteoblast-like cells in 2D and 3D culture conditions. Three bioinks with low, medium, and high viscosity prepared by supplementing a 5% GelMA solution with different concentrations of gelatin were evaluated. Cell responses were studied in a 2D environment after printing and incubation in non-cross-linked bioinks that caused the gelatin and GelMA to dissolve and release cells for attachment to tissue culture plates. The increased viscosity of the bioinks significantly affected cell area and aspect ratio. Cells printed using the bioink with medium viscosity exhibited greater metabolic activity and proliferation rate than those printed using the high viscosity bioink and even the unprinted control cells. Additionally, cells printed using the bioink with high viscosity demonstrated notably elevated expression levels of alkaline phosphatase (ALP) and bone morphogenetic protein-2 (BMP-2) genes. In the 3D condition, the printed cell-laden hydrogels were photo-cross-linked prior to incubation. The medium viscosity bioink supported greater cell proliferation compared to the high viscosity bioink. However, there were no significant differences in the expression of osteogenic markers between the medium and high viscosity bioinks. Therefore, the choice between medium and high viscosity bioinks should be based on the desired outcomes and objectives of the bone tissue engineering application. Furthermore, the bioprinting procedure with the medium viscosity bioink was used as an automated technique for efficiently seeding cells onto 3D printed porous titanium scaffolds for bone tissue engineering purposes.

Nanomaterials: leading immunogenic cell death-based cancer therapies.

The field of oncology has transformed in recent years, with treatments shifting from traditional surgical resection and radiation therapy to more diverse and customized approaches, one of which is immunotherapy. ICD (immunogenic cell death) belongs to a class of regulatory cell death modalities that reactivate the immune response by facilitating the interaction between apoptotic cells and immune cells and releasing specific signaling molecules, and DAMPs (damage-associated molecular patterns). The inducers of ICD can elevate the expression of specific proteins to optimize the TME (tumor microenvironment). The use of nanotechnology has shown its unique potential. Nanomaterials, due to their tunability, targeting, and biocompatibility, have become powerful tools for drug delivery, immunomodulators, etc., and have shown significant efficacy in clinical trials. In particular, these nanomaterials can effectively activate the ICD, trigger a potent anti-tumor immune response, and maintain long-term tumor suppression. Different types of nanomaterials, such as biological cell membrane-modified nanoparticles, self-assembled nanostructures, metallic nanoparticles, mesoporous materials, and hydrogels, play their respective roles in ICD induction due to their unique structures and mechanisms of action. Therefore, this review will explore the latest advances in the application of these common nanomaterials in tumor ICD induction and discuss how they can provide new strategies and tools for cancer therapy. By gaining a deeper understanding of the mechanism of action of these nanomaterials, researchers can develop more precise and effective therapeutic approaches to improve the prognosis and quality of life of cancer patients. Moreover, these strategies hold the promise to overcome resistance to conventional therapies, minimize side effects, and lead to more personalized treatment regimens, ultimately benefiting cancer treatment.

The early outcomes of two separate anastomosis procedures in deceased kidney transplantation with double arteries: A retrospective comparative study.

BACKGROUND: Kidneys with double renal arteries are used on a routine basis nowadays, and separate anastomosis in situ is one of the suitable arterial anastomosis procedures. The commonly used methods are parallel end-to-side anastomoses of double arteries to the external iliac artery, and end-to-end anastomosis to the internal iliac artery combined with end-to-side anastomosis to the external iliac artery. No studies have compared the prognoses of the two procedures in deceased kidney transplantation. METHODS: We retrospectively analyzed 35 consecutive deceased kidney transplantations with double arterial anastomoses in the urology department of China-Japan Friendship Hospital from January 2018 to April 2021. Group I comprised recipients with double parallel end-to-side anastomoses to the external iliac artery; Group II comprised the others. Their prognoses were then compared. RESULTS: There were no significant differences between Group I and II in characteristics of recipients and donors. The mean eGFRs at 1, 3, 6 and 12 months post-transplant in Group I and II were 36.4 vs 54.1 (P = 0.009), 40.4 vs 54.4 (P = 0.02), 40.4 vs 56.9 (P = 0.02) and 39.8 vs 57.9 (P = 0.007) mL/min respectively. There was no difference in early postoperative complications and 1-year survival rates between the two groups (P = 1.00). CONCLUSION: Separate anastomosis is a reliable procedure for deceased kidney transplantation with double arteries. Double separate anastomoses to the external and internal iliac arteries have better graft function compared with double parallel anastomoses to the external iliac artery during the first year after transplantation.

3D Printing and Surface Engineering of Ti6Al4V Scaffolds for Enhanced Osseointegration in an In Vitro Study.

Ti6Al4V superalloy is recognized as a good candidate for bone implants owing to its biocompatibility, corrosion resistance, and high strength-to-weight ratio. While dense metal implants are associated with stress shielding issues due to the difference in densities, stiffness, and modulus of elasticity compared to bone tissues, the surface of the implant/scaffold should mimic the properties of the bone of interest to assure a good integration with a strong interface. In this study, we investigated the additive manufacturing of porous Ti6Al4V scaffolds and coating modification for enhanced osteoconduction using osteoblast cells. The results showed the successful fabrication of porous Ti6Al4V scaffolds with adequate strength. Additionally, the surface treatment with NaOH and Dopamine Hydrochloride (DOPA) promoted the formation of Dopamine Hydrochloride (DOPA) coating with an optimized coating process, providing an environment that supports higher cell viability and growth compared to the uncoated Ti6Al4V scaffolds, as demonstrated by the higher proliferation ratios observed from day 1 to day 29. These findings bring valuable insights into the surface modification of 3D-printed scaffolds for improved osteoconduction through the coating process in solutions.

A novel nomogram for predicting the risk of persistent hyperparathyroidism after kidney transplantation.

PURPOSE: Persistent hyperparathyroidism (PTHPT) in kidney transplant recipients is associated with bone loss, graft dysfunction and cardiovascular mortality. There is no clear consensus on the management of PTHPT. Accurate risk prediction of the disease is needed to support individualized treatment decisions. We aim to develop a useful predictive model to provide early intervention for hyperparathyroidism in these patients. METHODS: We retrospectively analyzed 263 kidney transplantations in the urology department of China-Japan Friendship Hospital from January 2018 to December 2022. The overall cohort was randomly assigned 70% of the patients to the training cohort and 30% to the validation cohort. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for PTHPT and to construct the predictive model. This model was assessed regarding discrimination, consistency, and clinical benefit. RESULTS: The occurrence of PTHPT was 25.9% (68 out of 263 patients) in this study. Dialysis duration, postoperative 3-month intact parathyroid hormone (iPTH), 3-month corrected calcium (cCa), and 3-month phosphorus (P) are independent risk factors for the development of PTHPT. The nomogram showed good discrimination with the area under the curve (AUC) value of 0.926 in the training cohort and 0.903 in the validation cohort. The calibration curve and decision curve also showed that the model was well-evaluated. CONCLUSION: We developed a validated nomogram model to predict PTHPT after kidney transplantation. This can help the clinic prevent and control PTHPT early and improve patients' prognosis.

Natural rubber latex-based biomaterials for drug delivery and regenerative medicine: Trends and directions.

Natural Rubber Latex (NRL) has shown to be a promising biomaterial for use as a drug delivery system to release various bioactive compounds. It is cost-effective, easy to handle, biocompatible, and exhibits pro-angiogenic and pro-healing properties for both soft and hard tissues. NRL releases compounds following burst and sustained release kinetics, exhibiting first-order release kinetics. Moreover, its pore density can be adjusted for tailored kinetics profiles. In addition, biotechnological applications of NRL in amblyopia, smart mattresses, and neovaginoplasty have demonstrated success. This comprehensive review explores NRL's diverse applications in biotechnology and biomedicine, addressing challenges in translating research into clinical practice. Organized into eight sections, the review emphasizes NRL's potential in wound healing, drug delivery, and metallic nanoparticle synthesis. It also addresses the challenges in enhancing NRL's physical properties and discusses its interactions with the human immune system. Furthermore, examines NRL's potential in creating wearable medical devices and biosensors for neurological disorders. To fully explore NRL's potential in addressing important medical conditions, we emphasize throughout this review the importance of interdisciplinary research and collaboration. In conclusion, this review advances our understanding of NRL's role in biomedical and biotechnological applications, offering insights into its diverse applications and promising opportunities for future development.

Recent advances and perspectives on natural latex serum and its fractions for biomedical applications.

Advances and the discovery of new biomaterials have opened new frontiers in regenerative medicine. These biomaterials play a key role in current medicine by improving the life quality or even saving the lives of millions of people. Since the 2000s, Natural Rubber Latex (NRL) has been employed as wound dressings, mechanical barrier for Guided Bone Regeneration (GBR), matrix for drug delivery, and grafting. NRL is a natural polymer that can stimulate cell proliferation, neoangiogenesis, and extracellular matrix (ECM) formation. Furthermore, it is well established that proteins and other biologically active molecules present in the Natural Latex Serum (NLS) are responsible for the biological properties of NRL. NLS can be obtained from NRL by three main methods, namely (i) Centrifugation (fractionation of NRL in distinct fractions), (ii) Coagulation and sedimentation (coagulating NRL to separate the NLS from rubber particles), and (iii) Alternative extraction process (elution from NRL membrane). In this review, the chemical composition, physicochemical properties, toxicity, and other biological information such as osteogenesis, vasculogenesis, adhesion, proliferation, antimicrobial behavior, and antitumoral activity of NLS, as well as some of its medical instruments and devices are discussed. The progress in NLS applications in the biomedical field, more specifically in cell cultures, alternative animals, regular animals, and clinical trials are also discussed. An overview of the challenges and future directions of the applications of NLS and its derivatives in tissue engineering for hard and soft tissue regeneration is also given.

Detection and analysis of MEG signals in occipital region with double-channel OPM sensors.

BACKGROUND: Magnetoencephalography (MEG) has high temporal and spatial resolution and good spatial accuracy in determining the locations of source activity among most non-invasive imaging. The recently developed technology of optically-pumped magnetometer (OPM) has sensitivity comparable to that of the superconducting quantum interference device (SQUID) used in commercial MEG system. NEW METHOD: Double-channel OPM-MEG system detects human photic blocking of alpha rhythm at the occipital region of skull in the magnetically shielded environment via a wearable whole-cortex 3D-printed helmet. RESULTS: The alpha rhythm can be detected by the OPM-MEG system, the MEG signals are undoubtedly caused by photic blocking and similar with the results measured by SQUID magnetometer. COMPARISON WITH EXISTING METHODS: Due to the dependency of current commercial whole-cortex SQUID-MEG system on the liquid helium, the separation from the liquid helium space to the human head is usually at least a few centimeters. The wearable OPM-MEG system, however, can significantly improve the detection efficiency since its sensors can be mounted close to scalp, normally less than 1 cm. CONCLUSIONS: OPM-MEG system successfully detects alpha rhythm blocked by light stimulation and works well in the home-made magnetically shielded environment. OPM-MEG system shows a substitute for the traditional MEG system.

Analysis of sport-injured pattern of anterior cruciate ligament in the reconstruction period of Chinese college students.

BACKGROUND: In this study, we aimed to investigate the college students' injury patterns caused by sport activities in anterior cruciate ligament (ACL) reconstruction stage, and to estimate the association between activities at the time of injury and the odds of simplex ACL injuries. METHODS: A cohort of 2548 college students with primary ACL reconstruction was recruited from Hebei Province, China. Football, basketball, sprint, table tennis and badminton had been chosen as the most prevalent sports activities causing injuries in colleges. The concurrent injury patterns at the time of ACL reconstruction were simplex ACL, meniscus, cartilage, and multi-ligament injuries. RESULTS: Compared with football, college students playing basketball were 4.95 (95% confidence interval [CI], 2.61-8.76) times more likely to have simplex ACL tear, 2.31 (95% CI, 1.73-3.05) times more inclined to have lateral meniscus injury, 2.53 (95% CI, 1.22-3.67) times more likely to have a cartilage injury, and 1.93 (95% CI, 1.22-3.04) times more likely to have a medial meniscus injury. Students playing sprint were 2.04 (95% CI, 1.78-3.38) times more likely to have cartilage injury. CONCLUSIONS: Injury patterns are associated with certain sports. Compared with football, basketball has a greater possibility of leading to simplex ACL tear, as well as medial meniscus, lateral meniscus and cartilage injuries. Additionally, injury patterns observed during surgery may reflect the forces applied to the knee by the given sports performed.