New Designed Decellularized Scaffolds for Scaffold-based Gene Therapy from Elastic Cartilages via Supercritical Carbon Dioxide Fluid and Alkaline/Protease Treatments

Blood microbial analyses reveal long-term effects of SARS-CoV-2 infection on patients who recovered from COVID-19

OBJECTIVE

Few symptoms persist for a long time after patients recover from COVID-19, called "long COVID". We explored the potential microbial risk factors for COVID-19 for a deeper understanding and assistance in the follow-up treatment of these sequelae.

METHODS

Microbiome re-annotation was performed using whole blood RNA-Seq data collected from recovered COVID-19 patients and healthy controls at multiple time points. Subsequently, a series of downstream analyses were conducted to reveal the microbial characteristics of patients who recovered from SARS-CoV-2 infection.

RESULTS

The blood microbiome at 12 weeks post-infection was most evidently disturbed, including an increasing ratio of Bacillota/Bacteroidota and a higher microbial alpha diversity. In addition, a group of pathogenic microbes at 12 weeks post-infection were identified, including Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, which were positively associated with host genes involved in immune regulatory and olfactory transduction pathways. Several microbes, such as Streptococcus pneumoniae were associated with infiltrating immune cells, such as M2 macrophages.

CONCLUSION

This study provides insights into the relationship between the blood microbiome and COVID-19 sequelae. Several pathogenic microbes were enriched in recovered COVID-19 patients and thus affected host genes participating in the immune and olfactory transduction pathways, which play critical roles in COVID-19 sequelae.

Thermal and compositional characterization of chicken, beef, and pork cartilage to establish its lifetime

The thermal behavior of commercial chicken, beef, and pork cartilage, were studied using thermal analysis techniques. We use thermogravimetry (TGA) to study their thermal stability between room temperature and 500 °C; differential scanning calorimetry (DSC) in a temperature range between - 50 °C and 300 °C to determine their phase changes associated with endothermic or exothermic processes, and mass spectrometry coupled to TGA to determine the release of elements as they are heated; the results are similar for the three samples. In the thermogravimetric analysis, three different phases were found corresponding to the stages of dehydration (21 °C < T < 100 °C), decomposition (100 °C < T < 300 °C, and degradation (300 °C < T < 500 °C). The DSC study shows two endothermic anomalies corresponding to melting of the aqueous content (-25 °C < T < 25 °C) and evaporation of the aqueous content (27 °C < T < 175 °C), with required enthalpies of 137.30 J/g and 1193 J/g, respectively. Mass spectrometry evidenced the release of molecules such as nitrogen, oxygen, carbon dioxide, and calcium. This study intends to give an approximation to the possible behavior of commercial cartilage that is stored for use in surgery, in no way is it intended to simulate the behavior within the human body, since the biological and physicochemical parameters inside the body are not studied. From the TGA results for different heating rates, we calculated the activation energies required in each of the phases, whose values are 3250,95 J/mol in the dehydration stage, 5130,63 J/mol for decomposition, and 22,677,52 J/mol for degradation. With the activation energies and following the Toops theory (TOOP, 1971) [13], we proceeded to calculate the lifetime in the completion of the three stages or what in thermogravimetric analysis, is known as useful life per stage, finding that a sample of cartilage stored under ambient conditions, after 62 days it loses its initial properties. Which provides an important parameter for the storage of possible synthetic biomaterials with properties similar to cartilage. It is clear that here the useful life or the change of the original properties due to temperature effects is studied, which under the Arrhenius theory is transferred to the kinetic study over time.

Decellularized Extracellular Matrix for Remodeling Bioengineering Organoid's Microenvironment

Over the past decade, stem cell- and tumor-derived organoids are the most promising models in developmental biology and disease modeling, respectively. The matrix is one of three main elements in the construction of an organoid and the most important module of its extracellular microenvironment. However, the source of the currently available commercial matrix, Matrigel, limits the application of organoids in clinical medicine. It is worth investigating whether the original decellularized extracellular matrix (dECM) can be exploited as the matrix of organoids and improving organoid construction are very important. In this review, tissue decellularization protocols and the characteristics of decellularization methods, the mechanical support and biological cues of extraccellular matrix (ECM), methods for construction of multifunctional dECM and responsive dECM hydrogel, and the potential applications of functional dECM are summarized. In addition, some expectations are provided for dECM as the matrix of organoids in clinical applications.