Neural Regenerative Potential of Stem Cells Derived from the Tooth Apical Papilla

The regenerative effects of stem cells derived from dental tissues have been previously investigated. This study assessed the potential of human tooth stem cells from apical papilla (SCAP) on nerve regeneration. The SCAP collected from nine individuals were characterized and polarized by exposure to interferon-γ (IFN-γ). IFN-γ increased kynurenine and interleukin-6 (IL-6) production by SCAP, without affecting the cell viability. IFN-γ-primed SCAP exhibited a decrease of brain-derived neurotrophic factor (BDNF) mRNA levels, followed by an upregulation of glial cell-derived neurotrophic factor mRNA. Ex vivo, the co-culture of SCAP with neurons isolated from the rat dorsal root ganglion induced neurite outgrowth, accompanied by increased BDNF secretion, irrespective of IFN-γ priming. In vivo, the local application of SCAP reduced the mechanical and thermal hypersensitivity in Wistar rats that had been submitted to sciatic chronic constriction injury. The SCAP also reduced the pain scores, according to the evaluation of the Grimace scale, partially restoring the myelin damage and BDNF immunopositivity secondary to nerve lesion. Altogether, our results provide novel evidence about the regenerative effects of human SCAP, indicating their potential to handle nerve injury-related complications.

Nociceptin/orphanin FQ receptor modulates painful and fatigue symptoms in a mouse model of fibromyalgia

Generalized pain and fatigue are both hallmarks of fibromyalgia, a syndrome with an indefinite etiology. The treatment options for fibromyalgia are currently limited, probably because of its intricate pathophysiology. Thus, further basic and clinical research on this condition is currently needed. This study investigated the effects of nociceptin/orphanin FQ (N/OFQ) receptor (NOPr) ligands and the modulation of the NOP system in the preclinical mouse model of reserpine-induced fibromyalgia. The effects of administration of the natural agonist N/OFQ and the selective NOPr antagonists (UFP-101 and SB-612111) were evaluated in fibromyalgia-related symptoms in reserpine-treated mice. The expression of prepronociceptin/orphanin FQ and NOPr was assessed in central and peripheral sites at different time points after reserpine administration. Nociceptin/orphanin FQ displayed dual effects in the behavioral changes in the reserpine-elicited fibromyalgia model. The peptide NOPr antagonist UFP-101 produced analgesic and antifatigue effects, by preventing alterations in brain activity and skeletal muscle metabolism, secondary to fibromyalgia induction. The nonpeptide NOPr antagonist SB-612111 mirrored the favorable effects of UFP-101 in painful and fatigue alterations induced by reserpine. A time-related up- or downregulation of prepronociceptin/orphanin FQ and NOPr was observed in supraspinal, spinal, and peripheral sites of reserpine-treated mice. Our data shed new lights on the mechanisms underlying the fibromyalgia pathogenesis, supporting a role for N/OFQ-NOP receptor system in this syndrome.

Design and optimization of biocompatible polycaprolactone/poly (l-lactic-co-glycolic acid) scaffolds with and without microgrooves for tissue engineering applications

This study investigated the effects of smooth and microgrooved membrane blends, with different polycaprolactone (PCL)/ poly(lactic-co-glycolic acid) (PLGA) ratios on the viability, proliferation, and adhesion of different mammalian cell types. The polymer matrices with and without microgrooves, obtained by solvent casting, were characterized by field-emission scanning electron microscopy, atomic force microscopy, contact angle and Young's modulus. Blend characterization showed an increase in roughness and stiffness of membranes with 30% PLGA, without any effect on the contact angle value. Pure PCL significantly decreased the viability of Vero, HaCaT, RAW 264.7, and human fetal lung and gingival fibroblast cells, whereas addition of increasing concentrations of PLGA led to a reduced cytotoxicity. Increased proliferation rates were observed for all cell lines. Fibroblasts adhered efficiently to smooth membranes of the PCL70/PLGA30 blend and pure PLGA, compared to pure PCL and silicone. Microgrooved membranes promoted similar cell adhesion for all groups. Microstructured membranes (15 and 20-μm wide grooves) promoted suitable orientation of fibroblasts in both PCL70/PLGA30 and pure PLGA, as compared to pure PCL. Neuronal cells of the dorsal root ganglion exhibited an oriented adhesion to all the tested microgrooved membranes. Data suggest a satisfactory safety profile for the microgrooved PCL70/PLGA30 blend, pointing out this polymer combination as a promising biomaterial for peripheral nerve regeneration when cell orientation is required. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1522-1534, 2018.

Bio-electrospraying of human mesenchymal stem cells: An alternative for tissue engineering

Bio-electrospraying (BES) is a technique used for the processing of cells and can be applied to tissue engineering. The association of BES with scaffold production techniques has been shown to be an interesting strategy for the production of biomaterials with cells homogeneously distributed in the entire structure. Various studies have evaluated the effects of BES on different cell types. However, until the present moment, no studies have evaluated the impact of BES time on mesenchymal stem cells (MSC). Therefore, the aim of this work was to standardise the different parameters of BES (voltage, flow rate, and distance of the needle from the collecting plate) in relation to cell viability and then to evaluate the impact of BES time in relation to viability, proliferation, DNA damage, maintenance of plasticity and the immunophenotypic profile of MSC. Using 15 kV voltage, 0.46 ml/h flow rate and 4 cm distance, it was possible to form a stable and continuous jet of BES without causing a significant reduction in cell viability. Time periods between 15 and 60 min of BES did not cause alterations of viability, proliferation, plasticity, and immunophenotypic profile of the MSC. Time periods above 30 min of BES resulted in DNA damage; however, the DNA was able to repair itself within five hours. These results indicate that bio-electrospraying is an adequate technique for processing MSC which can be safely applied to tissue engineering and regenerative medicine.

Role of autologous mesenchymal stem cells associated with platelet-rich plasma on healing of cutaneous wounds in diabetic mice

BACKGROUND

Chronic cutaneous lesions affect 15% of human patients with diabetes, and the associated risk of limb amputations is 15-46 times greater than that of people with normal glycaemia. It is estimated that half of these limb amputations could be avoided by opportune treatment with somatic stem cells or platelet-rich plasma (PRP).

METHODS

We evaluated the effects of autologous transplant of mesenchymal stem cells (MSCs) with or without combination with autologous PRP in the re-epithelialization of cutaneous lesions induced in diabetic mice.

RESULTS

Animals treated with MSCs alone showed a similar level of re-epithelialization of cutaneous lesions to those treated with MSC plus PRP, and no significant difference was found between the two treatments.

CONCLUSION

Both treatments gave better results than daily cleaning of the cutaneous lesions with saline or covering of the lesions with semipermeable adherent bandage.

Methodology, biology and clinical applications of human mesenchymal stem cells

Stem cells are known by their capacity of self-renewal and differentiation into at least one specialized cell type. Mesenchymal stem cells (MSCs) were isolated initially from bone marrow but are now known to exist in any vascularized organ or tissue in adults. MSCs have a great therapeutic potential, due to their ability to migrate to sites of tissue injury and secrete trophic factors that hasten endogenous repair. They have also been shown to present immunosuppressive properties that may be used in the treatment of autoimmune or graft-versus-host diseases. Clinical trials employing MSCs show that the therapy is safe, but the efficiency needs to be in tested in phase III and IV studies. We describe here protocols for the isolation of human MSCs from human bone marrow and adipose tissue. The safe use of these cells demand a thorough in vitro characterization, as described in protocols of immunophenotyping by flow cytometry and analysis of their capacity to differentiate into adipogenic, osteogenic, and chondrogenic lineages.

Co-transplantation of mesenchymal stem cells maintains islet organisation and morphology in mice

AIMS/HYPOTHESIS

Recent studies have shown that mesenchymal stem cells (MSCs) secrete several factors that improve survival and function of transplanted islets. Implantation of islets beneath the kidney capsule results in morphological changes, due to interactions of the graft with the host, thus impairing islet function. We co-transplanted MSCs with islets to determine their effects on the remodelling process and studied graft function in a mouse model of minimal islet mass.

METHODS

Islets were syngeneically transplanted, either alone or with kidney-derived MSCs, underneath the kidney capsule of streptozotocin-induced diabetic C57Bl/6 mice. Blood glucose levels were monitored and intraperitoneal glucose tolerance tests carried out. Hormone contents of grafts and pancreas were assessed by radioimmunoassay. Graft morphology and vascularisation were evaluated by immunohistochemistry.

RESULTS

MSCs improved the capacity of islet grafts to reverse hyperglycaemia, with 92% of mice co-transplanted with MSCs reverting to normoglycaemia, compared with 42% of those transplanted with islets alone. Average blood glucose concentrations were lower throughout the 1 month monitoring period in MSC co-transplanted mice. MSCs did not alter graft hormone content. Islets co-transplanted with MSCs maintained a morphology that more closely resembled that of islets in the endogenous pancreas, both in terms of size, and of endocrine and endothelial cell distribution. Vascular engraftment was superior in MSC co-transplanted mice, as shown by increased endothelial cell numbers within the endocrine tissue.

CONCLUSIONS/INTERPRETATION

Co-transplantation of islets with MSCs had a profound impact on the remodelling process, maintaining islet organisation and improving islet revascularisation. MSCs also improved the capacity of islets to reverse hyperglycaemia.

Association between the 1858T allele of the protein tyrosine phosphatase nonreceptor type 22 and type 1 diabetes in a Brazilian population

The 1858T allele of the protein tyrosine phosphatase nonreceptor 22 (PTPN22) gene has been associated to diabetes in different populations. We investigated a possible relationship between this polymorphism and type 1 diabetes in a cohort of Brazilian patients. A significantly higher frequency of the 1858T allele was observed in diabetic patients (n = 211) than in control individuals (n = 241). Additionally, the heterozygote genotype was also increased in the diabetic group. No association was observed between the PTPN22 T allele and gender, or between T carriers and age of onset of T1D. This work describes for the first time a strong association of the 1858T allele with type 1 diabetes in a Brazilian population, reinforcing the role of this variant as an important susceptibility factor for this disease.

Mesenchymal stem cells reside in virtually all post-natal organs and tissues

Mesenchymal stem cells (MSCs) are multipotent cells which can give rise to mesenchymal and non-mesenchymal tissues in vitro and in vivo. Whereas in vitro properties such as (trans)differentiation capabilities are well known, there is little information regarding natural distribution and biology in the living organism. To investigate the subject further, we generated long-term cultures of cells with mesenchymal stem cell characteristics from different organs and tissues from adult mice. These populations have morphology, immunophenotype and growth properties similar to bone marrow-derived MSCs. The differentiation potential was related to the tissue of origin. The results indicate that (1) cells with mesenchymal stem characteristics can be derived and propagated in vitro from different organs and tissues (brain, spleen, liver, kidney, lung, bone marrow, muscle, thymus, pancreas); (2) MSC long-term cultures can be generated from large blood vessels such as the aorta artery and the vena cava, as well as from small vessels such as those from kidney glomeruli; (3) MSCs are not detected in peripheral blood. Taken together, these results suggest that the distribution of MSCs throughout the post-natal organism is related to their existence in a perivascular niche. These findings have implications for understanding MSC biology, and for clinical and pharmacological purposes.