Impact of ZrO2 Content on the Formation of Sr-Enriched Phosphates in Al2O3/ZrO2 Nanocomposites for Bone Tissue Engineering

This study investigates the profound impact of the ZrO2 inclusion volume on the characteristics of Al2O3/ZrO2 nanocomposites, particularly influencing the formation of calcium phosphates on the surface. This research, aimed at advancing tissue engineering, prepared nanocomposites with 5, 10, and 15 vol% ZrO2, subjecting them to chemical surface treatment for enhanced calcium phosphate deposition sites. Biomimetic coating with Sr-enriched simulated body fluid (SBF) further enhanced the bioactivity of nanocomposites. While the ZrO2 concentration heightened the oxygen availability on nanocomposite surfaces, the quantity of Sr-containing phosphate was comparatively less influenced than the formation of calcium phosphate phases. Notably, the coated nanocomposites exhibited a high cell viability and no toxicity, signifying their potential in bone tissue engineering. Overall, these findings contribute to the development of regenerative biomaterials, holding promise for enhancing bone regeneration therapies.

Adipose and amnion-derived mesenchymal stem cells: Extracellular vesicles characterization and implication for reproductive biotechnology

The stem cell-based research for reproductive biotechnology has been widely studied and shows promise for repairing defective tissue or degenerated cells to treat different diseases. The adipose tissue and amniotic membrane have awakened great interest in regenerative medicine and arises as a promising source of mesenchymal stem cells. Both types, adipose and amniotic derived mesenchymal stem cells (AMSCs) are multipotent cells with an enhanced ability to differentiate into multiple lineages.. We aimed to evaluate the effect of basal supplementation of exosomes in cell cultures with canine amniotic mesenchymal stem cells (MSCs). Mesenchymal stem cells derived from canine amniotic and adipose tissue were isolated and cultured performing cell passages until 80-90% confluence was reached. The growth curve was determined and peak cell growth was observed in the second passage. The cells were then characterized and differentiated into adipogenic, chondrogenic and osteogenic lineages. Extracellular vesicles from amnion were isolated using an ultracentrifugation protocol and characterized by nanosight analysis. To evaluate their ability to improve cellular viability in naturally inefficient passages, exosomes were co-cultures to the MSC cells. The results showed a 15-20% increase in the expansion rate of cultures supplemented with vesicles extracted in the first and second passages when compared to the control group. Statistical analysis using the Dunnett test (p ≤ 0.05) corroborated this result, showing a positive correlation between supplementation and expansion rate. These results indicate not only the importance of exosomes in the cell communication process but also the feasibility of the culture supplementation protocol for therapeutic purposes. The potential of the AMSCs for reproductive biotechnology is undoubted, however, their application to repair reproductive disorders and the involved mechanisms remain elusive. The strategies to enable the Adipose Stem Cells and AMSCs application in reproductive biotechnology and optimize their use for tissue regeneration open new venues using exosomes interactions.

Ozone therapy: protocol for treating canine parvovirus infection

Canine Parvovirus infection is a disease caused by Canine Parvovirus (CPV) that results in hemorrhagic gastroenteritis and secondary infections, mainly in puppies between six weeks and six months old that are not immunized. Since there is no specific treatment for the condition, supportive therapy based on antibiotics, antiemetics, and non-steroidal anti-inflammatory drugs is traditionally used. Ozone therapy is an economical treatment that has bactericidal, fungicidal, and antiviral properties, besides promoting oxygenation and tissue regeneration, as well as anti-inflammatory and analgesic effects, and was used as a complementary therapy in this study. Therefore, four mixed-breed dogs, aged between 2 and 3 months, with no previous immunization against CPV and testing positive for the virus in a rapid test were selected. The animals were randomly distributed into two groups, being 1: the control group (n=2) that received only supportive treatment; and 2: the experimental group (n=2), that in addition to conventional therapy received intravenously 500 mL of ozonized Ringer's Lactate solution. Before treatment and after 24 and 48 hours, the following clinical signs were evaluated: episodes of emesis and diarrhea, weight, hydration, blood glucose level, abdominal pain, and blood count. One control group animal died within the first hours of hospitalization. Both animals in the experimental group presented faster resolution of diarrheal episodes and shorter hospitalization time when compared to the surviving animal that received only supportive treatment. Although further studies are needed, ozone therapy showed promising results for the treatment of canine parvovirus.

HEK293T Cells with TFAM Disruption by CRISPR-Cas9 as a Model for Mitochondrial Regulation

The mitochondrial transcription factor A (TFAM) is considered a key factor in mitochondrial DNA (mtDNA) copy number. Given that the regulation of active copies of mtDNA is still not fully understood, we investigated the effects of CRISPR-Cas9 gene editing of TFAM in human embryonic kidney (HEK) 293T cells on mtDNA copy number. The aim of this study was to generate a new in vitro model by CRISPR-Cas9 system by editing the TFAM locus in HEK293T cells. Among the resulting single-cell clones, seven had high mutation rates (67-96%) and showed a decrease in mtDNA copy number compared to control. Cell staining with Mitotracker Red showed a reduction in fluorescence in the edited cells compared to the non-edited cells. Our findings suggest that the mtDNA copy number is directly related to TFAM control and its disruption results in interference with mitochondrial stability and maintenance.

Isolation and characterization of neural stem cells from fetal canine spinal cord

Neurogenesis in adult mammals occurs mainly in the subventricular and subgranular areas of the brain, but there are also reports of its occurrence in the spinal cord. In a study on rats, neural stem cells and neuroprogenitor cells could be obtained through primary spinal cord culture, but there are no studies on these cells in canine species, to date. Dogs represent an appropriate animal model for studies on neurogenesis and neurological disorders. In addition, they are animals of great affective value, and the therapeutic use of neural stem cells can represent a breakthrough in regenerative veterinary medicine. Therefore, this study aimed to determine a protocol for the isolation, culture, and characterization of neural and neuroprogenitor stem cells derived from the spinal cord of canine fetuses. The cells were isolated from spinal cord fragments and cultured in serum-free culture medium supplemented with EGF and FGF-2 growth factors. These cells were observed daily by optical microscopy to analyze their morphological characteristics. From the third day in vitro, it was possible to observe translucent cell groupings, similar to the neurospheres, which approximately ranged from 50 µm to 200 µm at seven days in vitro. Throughout the culture period, the neurospheres developed ribbons in their periphery that migrated and communicated with other neurospheres. RT-PCR revealed that the cells expressed the characteristic genes SOX2, NESTIN, and GFAP. In addition to gene expression, the cells were phenotypically marked in the immunofluorescence assay for the proteins Nestin, GFAP, and β-tubulin III, characterizing them as neurospheres. Our results suggest that the spinal cord may be a source of neural stem cells and neural progenitor cells in canine fetuses. These cells may be an interesting option for neurogenesis and neuroregenerative therapy studies.

Intense transmission of visceral leishmaniasis in a region of northeastern Brazil: a situation analysis after the discontinuance of a zoonosis control program

In São Luís, Maranhão, northeastern Brazil, the notification of visceral leishmaniasis (VL) cases intensified in 1982, showing endemic and epidemic patterns. In this city, the Center for Zoonoses Control (CZC) was an organization in charge of the control and prevention of the disease. However, technical and political reasons have led to a significant decline in the periodicity of its activities. Therefore, in this study we evaluated the epidemiological scenario of human visceral leishmaniasis (HVL) and the prevalence of the disease in dogs after the cessation of the CZC activities, covering the period of 2007 to 2016. The seroprevalence of canine leishmaniasis was determined based on clinical and serological profiles. HVL cases were notified using data provided by the Municipal Health Department of São Luís. A seropositivity rate of 45.8% (p = 0.0001) was found among dogs, 54% (p = 0.374) of which were asymptomatic. As for human cases, there were 415 notifications, with an increase in the incidence of the zoonosis observed during the aforementioned period. Thus, it can be inferred that after the control and surveillance activities were curtailed, there was an increase in the number of seropositive animals in circulation, acting as reservoirs of infection for dogs and humans.