Lisiane Bernardi

Nanofiber Scaffolds Support Bone Regeneration Associated with Pulp Stem Cells

Currently, there are a number of alternatives for bone grafting, though when used correctly they present physical, chemical or biological limitations, which justifies the pursuit for new alternatives for bone regeneration. This study gives a report on the potential for bone regeneration in the use of biodegradable nanofibers from poly (lactic-co-glycolic acid) (PLGA) in association with human mesenchymal stem cells from dental pulp of deciduous teeth (SCDT). Five samples of SCDT were seeded with scaffolds (test) or without scaffolds (control) for cell adhesion and viability assay. To evaluate the ability of the association in promoting bone formation, critical defects were made in the calvarium of rats (n=20), which were then divided into the following groups: I--sham group; II--implant of scaffolds; III--scaffolds/ SCDT; and IV--scaffolds/SCDT. They were kept for 13 days in osteogenic media. After 60 days, the histomorphometric analysis was performed. It was observed that the adherence and viability of SCDT in the control and test group were similar throughout the experiment (p>0.05). The association of scaffolds/SCDT maintained in osteogenic media, showed greater bone formation than the other groups (p<0.05). The study demonstrated that the association of SCDT seeded in biodegradable PLGA scaffolds has the ability to promote bone regeneration in rats, which is a promising alternative for application in regenerative medicine.

Low Doses of Curcuma longa Modulates Cell Migration and Cell–Cell Adhesion

Cell invasion and metastasis are involved in clinical failures in cancer treatment, and both events require the acquisition of a migratory behavior by tumor cells. Curcumin is a promising natural product with anti‐proliferative activity, but its effects on cell migration are still unclear. We evaluated the effects of curcumin on the proliferation, apoptosis, migration, and cell–cell adhesion of keratinocyte, oral squamous cell carcinoma (OSCC), and fibroblast cell lines, as well as in a xenograft model of OSCC. Curcumin (2 μM) decreased cell proliferation in cell lines with mesenchymal characteristics, while cell death was detected only at 50 μM. We observed that highly migratory cells showed a decrease on migration speed and directionality when treated with 2 or 5 μM of curcumin (50% and 40%, respectively, p < 0.05). Using spheroids, we observed that curcumin dose dependently decreased cell–cell adhesion, especially on tumor‐derived spheroids. Also, in a xenograft model with patient‐derived OSCC cells, the administration of curcumin decreased tumor growth and aggressiveness when compared with untreated tumors, indicating the potential antitumor effect in oral cancer. These results suggest that lower doses of curcumin can influence several steps involved in tumorigenesis, including migration properties, suggesting a possible use in cancer therapy. Copyright

Aging process alters hippocampal and cortical secretase activities of Wistar rats

HighlightsAged brains have an imbalance between amyloidogenic and non‐amyloidogenic pathways.Lower cortical TACE activity was linked to aging‐induced aversive memory impairment.Treadmill exercise was unable to alter hippocampal and cortical secretase activities. ABSTRACT A growing body of evidence has demonstrated amyloid plaques in aged brain; however, little attention has been given to amyloid precursor protein (APP) processing machinery during the healthy aging process. The amyloidogenic and non‐amyloidogenic pathways, represented respectively by &bgr;‐ and &agr;‐secretases (BACE and TACE), are responsible for APP cleavage. Our working hypothesis is that the normal aging process could imbalance amyloidogenic and non‐amyloidogenic pathways specifically BACE and TACE activities. Besides, although it has been showed that exercise can modulate secretase activities in Alzheimer Disease models the relationship between exercise effects and APP processing during healthy aging process is rarely studied. Our aim was to investigate the aging process and the exercise effects on cortical and hippocampal BACE and TACE activities and aversive memory performance. Young adult and aged Wistar rats were subjected to an exercise protocol (20 min/day for 2 weeks) and to inhibitory avoidance task. Biochemical parameters were evaluated 1 h and 18 h after the last exercise session in order to verify transitory and delayed exercise effects. Aged rats exhibited impaired aversive memory and diminished cortical TACE activity. Moreover, an imbalance between TACE and BACE activities in favor of BACE activity was observed in aged brain. Moderate treadmill exercise was unable to alter secretase activities in any brain areas or time points evaluated. Our results suggest that aging‐related aversive memory decline is partly linked to decreased cortical TACE activity. Additionally, an imbalance between secretase activities can be related to the higher vulnerability to neurodegenerative diseases induced by aging.

Intracardiac Injection of Dental Pulp Stem Cells After Neonatal Hypoxia-Ischemia Prevents Cognitive Deficits in Rats

Neonatal hypoxia-ischemia (HI) is associated to cognitive and motor impairments and until the moment there is no proven treatment. The underlying neuroprotective mechanisms of stem cells are partially understood and include decrease in excitotoxicity, apoptosis and inflammation suppression. This study was conducted in order to test the effects of intracardiac transplantation of human dental pulp stem cells (hDPSCs) for treating HI damage. Seven-day-old Wistar rats were divided into four groups: sham-saline, sham-hDPSCs, HI-saline, and HI-hDPSCs. Motor and cognitive tasks were performed from postnatal day 30. HI-induced cognitive deficits in the novel-object recognition test and in spatial reference memory impairment which were prevented by hDPSCs. No motor impairments were observed in HI animals. Immunofluorescence analysis showed human-positive nuclei in hDPSC-treated animals closely associated with anti-GFAP staining in the lesion scar tissue, suggesting that these cells were able to migrate to the injury site and could be providing support to CNS cells. Our study evidence novel evidence that hDPSC can contribute to the recovery following hypoxia-ischemia and highlight the need of further investigation in order to better understand the exact mechanisms underlying its neuroprotective effects.

Effects of Diabetes and Hypertension on Oral Mucosa and TGFβ1 Salivary Levels

The aim of this study was to investigate salivary levels of TGFβ1 and proliferation/ maturation of epithelial mucosa cells in diabetic and hypertensive patients. DESIGN in this cross-sectional study, whole stimulated saliva and oral mucosa exfoliative cytology specimens were collected from 39 patients that were healthy (control, n=10) or presented history of arterial hypertension (HAS, n=9), diabetes mellitus (DM, n=10) or both (DM+HAS, n=10). Salivary flow rate (SFR), TGFβ1 level in saliva, AgNORs and the epithelial maturation were evaluated. Non-parametric Kruskal-Wallis test, followed by Dunns multiple comparison post-test and the Spearman test correlation analysis were used. SFR showed a significant decreased in DM and DM+HAS (0.47±0.11 and 0.64±0.43 mL/min) when compared to control (1.4±0.38 mL/min). DM+HAS presented the highest value of TGFβ1 concentration (24.72±5.89 pg/mL). It was observed a positive correlation between TGFβ1 and glycaemia (R=0.6371; p<0.001) and a negative correlation between TGFβ1 and saliva (R=-0.6162; p<0.001) and glycaemia and SFR (R=-0.5654; P=0.001). AgNORs number and status of maturation of mucosa cells were similar for all conditions. DM and DM+HAS presented the lowest SFR, which correlated with increased TGFβ1 levels. Despite the higher TGFβ1 secretion it was not observed changes in the morphology or proliferation of epithelial cells when diabetes or hypertension was present.

NADPH-oxidase-derived ROS alters cell migration by modulating adhesions dynamics: NADPH-oxidase-derived ROS affects cell adhesion

Cell migration requires the coordinated activation of structural and signalling molecules, such as the RhoGTPase Rac1. It is known that the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex assembly, which generates reactive oxygen species (ROS) at the cell membrane, also relies on Rac1 activation, indicating a possible effect of ROS during cell migration. In this study, we evaluated the effect of NADPH‐oxidase‐derived ROS on the migration process.

Long- and short-term diabetes mellitus type 1 modify young and elder rat salivary glands morphology

OBJECTIVE In this study we performed a temporal analysis of the effects of Diabetes Mellitus on morphology and laminin deposition in salivary glands of young (2 months-old) and aging (12 months-old) male Wistar rats, using immunohistochemistry. MATERIALS AND METHODS The animals were divided in control and diabetic (Streptozotocin induced) groups and euthanized after short and long-term diabetes induction. RESULTS Short-term induction led to vacuolization of parotid acinar cells and increased laminin deposition in both animal ages. In young rats, no difference was observed between short or long-term diabetes regarding laminin deposition, but parotid acinar cells vacuolization was more discrete after long-term diabetes. A slight decrease of submandibular gland convoluted granular ducts was observed in young and elder diabetic animal ages. In diabetic aging rats was observed an increase of laminin content only in the parotid gland. CONCLUSIONS These results suggest that some Diabetes Mellitus effects on salivary glands are not progressive over time, possibly due to the existence of adaptive mechanisms in response to chronic hyperglycemia. They also show that the duration of the disease was more relevant to the morphological effects than the age, although it is known that aging per se affects salivary gland morphology and function.

X-ray irradiation alters the actin cytoskeleton in murine lacrimal glands

Abstract Objective. The aim of this study was to evaluate the effects of X radiation on the distribution of filamentous actin (F-actin) in the mouse exorbital lacrimal gland. Materials and methods. Mice were divided into groups that received no radiation (n = 6) or one single exposure of 36 mGy of X radiation (n = 12). The animals were sacrificed after 4, 8 or 24 h. The lacrimal glands were stained with Hematoxylin/Eosin or Rhodamine-phalloidin and the filamentous actin arrangement was analyzed by confocal microscopy. Results. After 4 h of X-ray exposure there was an apparent increase in acini area and a decrease in the cortical F-actin content in secretory cells. This effect decreased gradually over time, returning to values close to the control after 24 h. Conclusion. This study shows that a 36mGy diagnostic X-ray dose affected reversibly the mouse exorbital lacrimal gland, suggesting that radiation used in diagnosis may induce changes on cell morphology due to actin remodeling.