Tissue Bioengineering with Fibrin Scaffolds and Deproteinized Bone Matrix Associated or Not with the Transoperative Laser Photobiomodulation Protocol.

Extending the range of use of the heterologous fibrin biopolymer, this pre-clinical study showed a new proportionality of its components directed to the formation of scaffold with a lower density of the resulting mesh to facilitate the infiltration of bone cells, and combined with therapy by laser photobiomodulation, in order to accelerate the repair process and decrease the morphofunctional recovery time. Thus, a transoperative protocol of laser photobiomodulation (L) was evaluated in critical bone defects filled with deproteinized bovine bone particles (P) associated with heterologous fibrin biopolymer (HF). The groups were: BCL (blood clot + laser); HF; HFL; PHF (P+HF); PHFL (P+HF+L). Microtomographically, bone volume (BV) at 14 days, was higher in the PHF and PHFL groups (10.45 ± 3.31 mm3 and 9.94 ± 1.51 mm3), significantly increasing in the BCL, HFL and PHFL groups. Histologically, in all experimental groups, the defects were not reestablished either in the external cortical bone or in the epidural, occurring only in partial bone repair. At 42 days, the bone area (BA) increased in all groups, being significantly higher in the laser-treated groups. The quantification of bone collagen fibers showed that the percentage of collagen fibers in the bone tissue was similar between the groups for each experimental period, but significantly higher at 42 days (35.71 ± 6.89%) compared to 14 days (18.94 ± 6.86%). It can be concluded that the results of the present study denote potential effects of laser radiation capable of inducing functional bone regeneration, through the synergistic combination of biomaterials and the new ratio of heterologous fibrin biopolymer components (1:1:1) was able to make the resulting fibrin mesh less dense and susceptible to cellular permeability. Thus, the best fibrinogen concentration should be evaluated to find the ideal heterologous fibrin scaffold.

Therapeutic Effects of Citrus Flavonoids Neohesperidin, Hesperidin and Its Aglycone, Hesperetin on Bone Health.

Flavonoids are natural phytochemicals that have therapeutic effects and act in the prevention of several pathologies. These phytochemicals can be found in seeds, grains, tea, coffee, wine, chocolate, cocoa, vegetables and, mainly, in citrus fruits. Neohesperidin, hesperidin and hesperetin are citrus flavonoids from the flavanones subclass that have anti-inflammatory and antioxidant potential. Neohesperidin, in the form of neohesperidin dihydrochalcone (NHDC), also has dietary properties as a sweetener. In general, these flavanones have been investigated as a strategy to control bone diseases, such as osteoporosis and osteoarthritis. In this literature review, we compiled studies that investigated the effects of neohesperidin, hesperidin and its aglycone, hesperetin, on bone health. In vitro studies showed that these flavanones exerted an antiosteoclastic and anti- inflammatory effects, inhibiting the expression of osteoclastic markers and reducing the levels of reactive oxygen species, proinflammatory cytokines and matrix metalloproteinase levels. Similarly, such studies favored the osteogenic potential of preosteoblastic cells and induced the overexpression of osteogenic markers. In vivo, these flavanones favored the regeneration of bone defects and minimized inflammation in arthritis- and periodontitis-induced models. Additionally, they exerted a significant anticatabolic effect in ovariectomy models, reducing trabecular bone loss and increasing bone mineral density. Although research should advance to the clinical field, these flavanones may have therapeutic potential for controlling the progression of metabolic, autoimmune or inflammatory bone diseases.

Potential of Fibrin Glue and Mesenchymal Stem Cells (MSCs) to Regenerate Nerve Injuries: A Systematic Review.

Cell-based therapy is a promising treatment to favor tissue healing through less invasive strategies. Mesenchymal stem cells (MSCs) highlighted as potential candidates due to their angiogenic, anti-apoptotic and immunomodulatory properties, in addition to their ability to differentiate into several specialized cell lines. Cells can be carried through a biological delivery system, such as fibrin glue, which acts as a temporary matrix that favors cell-matrix interactions and allows local and paracrine functions of MSCs. Thus, the aim of this systematic review was to evaluate the potential of fibrin glue combined with MSCs in nerve regeneration. The bibliographic search was performed in the PubMed/MEDLINE, Web of Science and Embase databases, using the descriptors ("fibrin sealant" OR "fibrin glue") AND "stem cells" AND "nerve regeneration", considering articles published until 2021. To compose this review, 13 in vivo studies were selected, according to the eligibility criteria. MSCs favored axonal regeneration, remyelination of nerve fibers, as well as promoted an increase in the number of myelinated fibers, myelin sheath thickness, number of axons and expression of growth factors, with significant improvement in motor function recovery. This systematic review showed clear evidence that fibrin glue combined with MSCs has the potential to regenerate nervous system lesions.

Effects of isotretinoin on the metabolism of triglyceride-rich lipoproteins and on the lipid profile in patients with acne.

Isotretinoin treatment alters the plasma lipid levels but the mechanisms and the effects on the metabolism of triglyceride-rich lipoproteins such as chylomicrons and very-low-density lipoproteins remain unclear. We investigated the effect of isotretinoin on the plasma kinetics of emulsion models of triglyceride-rich lipoproteins and the lipid profile. Ten patients with acne were treated with 0.8 mg/kg of isotretinoin over 4 weeks for comparison with non-treated acne patients. In both groups the plasma kinetic study of a triglyceride-rich emulsion double-labeled with 14C-cholesterol oleate and 3H-triolein was performed after intravenous injection of the emulsion and radioactive counting in plasma samples collected over 60 min. Patients using isotretinoin showed decreased removal from the plasma of the 3H-triglyceride (median 0.019 min-1 TG) compared with controls (median 0.044 min-1, P=0.007), and the removal of the emulsion 14C-cholesterol oleate also tended to be decreased (treatment: 0.011 min-1; controls: 0.024 min-1, P=0.06). The values of total and LDL cholesterol and triglycerides were increased post-treatment (P<0.03). In conclusion, while increasing the fasting plasma concentration of VLDL and LDL, which are traditional risk factors for atherosclerosis, isotretinoin treatment also slows down the metabolism of triglyceride-rich lipoproteins such as chylomicrons, as tested by the emulsion model, an effect that is also increasingly recognized as atherogenic.